Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/27/12
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1012 PM EST THU JAN 26 2012
.SYNOPSIS...
LOW PRESSURE WILL PUSH ACROSS THE REGION TONIGHT INTO TOMORROW
BRING RAIN ACROSS THE COASTAL REGIONS...AND MIXED PRECIP TO THE
INTERIOR. WEAK HIGH PRESSURE SHOULD BRING COOL BUT SEASONABLE
WEATHER DURING SATURDAY. TWO AREAS OF LOW PRESSURE PASS NORTH OF
SOUTHERN NEW ENGLAND SATURDAY NIGHT AND SUNDAY NIGHT. THE SUNDAY
NIGHT LOW PRESSURE WILL BE MORE SUBSTANTIAL AND BRING A CHANCE OF
RAIN AND SNOW SHOWERS TO OUR AREA. DRY AND SEASONABLY MILD WEATHER
RETURNS DURING NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
10AM UPDATE...
MINOR ADJUSTMENTS TO THE FORECAST TO ACCOUNT FOR CURRENT TRENDS.
NOSE OF THE WAA IS CURRENT LOCATED OVER CENTRAL MASS...WHICH
LOOKING AT RADAR IMAGERY AND OBSERVATION IS THE REGION WHERE THE
MIX PRECIP LINE IS LOCATED. EXPECT THESE SITES TO BEGIN THE
TRANSITIONS TO RAIN BY NEXT UPDATE. ACROSS NEW HAMPSHIRE...A MIX
OF FREEZING RAIN AND SNOW IS STILL BEING REPORTED. EXPECT SNOW TO
TRANSITION TO FREEZING RAIN WITHIN THE NEXT FEW HOURS. FREEZING
RAIN SHOULD REMAIN PERSISTENT ACROSS NEW HAMPSHIRE THROUGH THE
MORNING HOURS. SOUTH OF THE MASS PIKE AND ACROSS THE
COAST...EXPECT ALL RAIN TO CONTINUE WITH A T TO 0.10 INCHES
MEASURED ALREADY. PRECIP SWATH WILL CONTINUE AS LOW PRESSURE MOVES
CLOSER TO NEW ENGLAND. PLAN ON CONTINUING THE ADVISORY AREA WIDE AS
TEMPS ARE STILL CLOSE TO FREEZING ACROSS CT AND WESTERN MASS SOUTH
OF THE MASS PIKE.
7 PM UPDATE...
PRECIP HAS STARTED OVER MOST OF THE FORECAST AREA. OBSERVATIONS
REPORT PTYPE AS RAIN SOUTH OF THE MASS PIKE WITH SNOW TO THE
NORTH. CEF REPORTED SLEET AT 6 PM. PVD INITIATED WITH LIGHT SLEET
BUT QUICKLY CHANGED TO LIGHT RAIN.
PCPN THAT BEGAN AS SNOW IN THE SPRINGFIELD AREA CHANGED TO RAIN
AFTER 3 HOURS. WITH WARM AIR MOVING NORTH OVERNIGHT WE EXPECT THIS
CHANGEOVER TO SHIFT NORTH WITH TIME. THE AFTERNOON MODELS SHOWED A
30-40 KNOT AGEOSTROPIC DRAINAGE WIND INTO SOUTHWEST NH AND
NORTHWEST MASS...SO DIGGING OUT THE COLD SURFACE AIR WILL BE A
CHORE OVERNIGHT AND EARLY FRIDAY.
THE UPDATE INCLUDES ADJUSTMENTS TO TEMPS AND DEWPOINTS BASED ON
OBSERVATION. WE HAVE ALSO LOADED THE HRRR WINDS THROUGH 06Z AS
THESE BEST REFLECTED THE WIND DIRECTION CHANGE AT BOS.
PREVIOUS DISCUSSION...
NEW TEMP COLUMN DATA STILL SUPPORTS INITIAL MIX OF SN/PL/FZRA
ACROSS THE INTERIOR AS ISENTROPIC LIFT STRENGTHENS WITH THE WARM
FROPA. LLVL WARM AIR WILL BE QUICKEST TO REACH AREAS S OF THE MA
PIKE AS WELL AS WITHIN THE I-495 CORRIDOR. EXPECTING THESE
AREAS...AFTER A BRIEF PERIOD OF PL/SN/RA...TO QUICKLY TRANSITION
TO ALL RAIN ESPECIALLY AFTER MIDNIGHT. OUTSIDE OF THESE AREAS /N
CENTRAL AND WRN MA...N CENTRAL CT...AND SRN NH/ A PERIOD OF EVAP
COOLING AND NORMAL DIURNAL COOLING WILL ALLOW SOME PL/SN TO START
PRECIP THIS EVENING. GIVEN THESE COOLING FACTORS...2M TEMPS WILL
BE SLOW TO RISE OVERNIGHT...SO AS LOW TO MID LVLS OF THE COLUMN
RAPIDLY WARM WITH THE FRONT ALOFT...RAIN WILL BEGIN TO FALL ONTO A
NEAR 0C SURFACE. THEREFORE...SOME ICE ACCUMULATION REMAINS LIKELY
IN THESE AREAS. QPF VALUES OVERNIGHT RANGE 0.25 TO 0.5 INCHES.
GIVEN TEMPS ICE ACCUMULATIONS OF A QUARTER TO EVEN A THIRD OF AN
INCH ARE POSSIBLE...WITH THE HIGHEST AMOUNTS IN SRN NH...WHICH
WILL REMAIN NEAR FREEZING FOR THE LONGEST PERIOD OF TIME. IT
SHOULD BE NOTED THAT EXACT TIMING OF TRANSITION IS SOMEWHAT
UNCERTAIN AS IT WILL DEPEND STRONGLY ON THE QUICKNESS OF THE WARM
AIR AND THE ROBUSTNESS OF THE INITIAL COOLING/SNOWFALL. LATEST
GUIDANCE 2M TEMPS ARE ALSO A BIT WARMER THAN PREVIOUS FORECAST.
PLEASE STAY TUNED TO WINTER WEATHER ADVISORY UPDATES AS THEY COME
OUT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
LLVL WARM FRONT WILL BE PUSHING N OF THE MA PIKE THROUGH THE
MORNING HOURS BASED ON LATEST GUIDANCE TIMING. THEREFORE...ANY
AREAS OF SOUTHERN NEW ENGLAND S OF THE MASS PIKE AND IMMEDIATELY
TO THE N SHOULD BE TRANSITIONING TO ALL RAIN. BEFORE PRECIP
BECOMES ALL RAIN...A BIT MORE ICE ACCUMULATION IS POSSIBLE IN THE
AFOREMENTIONED AREAS SINCE A FEW HOURS OF FZRA ARE POSSIBLE
THROUGH AT LEAST THE MID MORNING HOURS...ESPECIALLY IN SRN NH. THE
DEEPENING LOW PRES ASSOCIATED WITH THE FRONT WILL BE MOVING ALMOST
DIRECTLY OVER THE AREA FROM SW TO NE DURING THE AFTERNOON HOURS.
THEREFORE...ONCE THE LOW SHIFTS E AND CAA COMMENCES ON THE BACK
SIDE LATE IN THE DAY...ALL PRECIP SHOULD BE GRADUALLY COMING TO AN
END FROM W TO E. H92 TEMPS WITHIN THE WARM LAYER REACH AROUND +12C
ALONG SRN PORTIONS OF THE FA...SO TEMPS REACHING INTO THE 50S ARE
LIKELY WHILE NRN AREAS REMAIN IN THE 40S.
GIVEN THE RAPIDLY DEEPENING LOW WITH PRES CHANGES OF 1 TO 2MB PER
HOUR...ISALLOBARIC FLOW WILL BE QUITE STRONG BOTH JUST AHEAD AND
QUITE STRONG WITH EQUAL RISES BEHIND THE EXITING LOW. BOTH NAM/GFS
SHOW A NEAR 60 KT H92 LLJ CLIPPING THE SRN TIER DURING THE 12Z-
18Z PERIOD. HOWEVER...DESPITE THESE DYNAMIC FACTORS...A STRONG
INVERSION WILL BE IN PLACE GIVEN THAT UPPER LVL WARM FRONT MOVES
WELL AHEAD OF THE LLVL FRONT. SO ATTM...NOT EXPECTING MUCH MIXING
WITH THIS INITIAL JET. HOWEVER...STRONG SFC PRES CHANGES DO
SUGGEST THAT SUSTAINED WINDS MAY COME CLOSE TO THE 27 KT ADVISORY
THRESHOLD OVER THE CAPE/ISLANDS/S COAST BOTH DURING THE MORNING
JET PASSAGE AND MUCH LATER IN THE EVENING AS THE LOW MOVES E AND
CAA COMMENCES...AND A *FEW* RAW MODEL OUTPUTS SUPPORT THIS. GIVEN
THE STRONG MITIGATING FACTORS /STRONG INVERSION/ AND PRES RISES NOT
EXCEEDING THE 2MB PER HOUR THAT MOST OFTEN ACCOMPANIES STRONG
WINDS...HAVE HELD OFF ON WIND HEADLINES FOR THIS UPDATE.
HOWEVER...THIS WILL NEED TO BE MONITORED DURING FUTURE UPDATES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
BIG PICTURE...
HUDSON BAY UPPER LOW CARVES A BROAD UPPER TROUGH OVER THE EASTERN
USA DURING THE WEEKEND AND EARLY NEXT WEEK. THE FLOW THEN BECOMES
MORE ZONAL FOR MIDWEEK. THUS EXPECT A COOLING TREND OVER THE
WEEKEND FOLLOWED BY A TREND BACK TO SEASONABLY MILD TEMPS DURING
NEXT WEEK.
ONE SHORTWAVE PASSES ACROSS CANADA SATURDAY NIGHT WITH MOST OF THE
SUPPORT AND MOISTURE REMAINING NORTH OF US. ANOTHER RUNS THROUGH
THE BASE OF THE UPPER TROUGH SUNDAY NIGHT. A THIRD WAVE PASSES
NORTH OF US ON WEDNESDAY...ALTHOUGH WITH A ZONAL FLOW THE TIMING ON
THIS PASSAGE IS LOW CONFIDENCE.
THE WEEKEND FORECAST DRAWS FROM A MIX OF MOS DATA. THE LONGER TERM
FORECAST DRAWS FROM THE 12Z ECMWF AND HPC GRIDDED VALUES.
FRIDAY NIGHT...
PRESSURE RISES TRAILING THE GULF OF MAINE SURFACE LOW WILL BE 1-2
MB/HOUR. THIS SHOULD SUPPORT A BLUSTERY NW WIND OVERNIGHT. THE NAM
SHOWS SUFFICIENT COOLING ALOFT TO SUPPORT 30 KNOT GUSTS. THE GFS
SHOWS 50-60 KNOT WINDS AT 900-950 MB...BUT LAPSE RATES LESS THAN
5C/KM AND SO MORE QUESTIONABLE MIXING. THE BEST CHANCE FOR MIXING
STRONG WINDS TO THE SURFACE WOULD BE OVER THE CAPE AND ISLANDS...AND
POSSIBLY ACROSS THE HILLTOPS. FOR NOW WE HAVE GONE WITH LAND GUSTS
25-30 KNOTS. WINDS SHOULD DIMINISH OVERNIGHT AS THE SURFACE LOW
MOVES FARTHER AWAY.
SATURDAY...
WEAK OFFSHORE HIGH BUILDS OVER THE FORECAST AREA AND THEN OFF TO THE
EAST IN THE AFTERNOON. LOW PRESSURE MOVING ACROSS CANADA SWINGS A
FRONT THROUGH THE REGION SATURDAY EVENING. LIMITED MOISTURE WITH
THIS SYSTEM...WITH MODELS INDICATING MOST OF THE MOISTURE OVER US
WILL BE AT MID LEVELS. BEST CHANCE OF PCPN WILL BE IN NORTHERN NEW
ENGLAND CLOSER TO THE TRACK OF THE LOW. EXPECT INCREASING CLOUDS
AFTERNOON AND EVENING AS THE FRONT APPROACHES...THEN CLEARING
SATURDAY NIGHT...AND NO POPS.
SUNDAY...
ANOTHER SHORTWAVE APPROACHES SIMILAR TO SATURDAY. THIS ONE IS
PROJECTED TO HAVE MORE MOISTURE ALOFT...AND A MORE SOUTHERLY TRACK
THAT WILL DRAW THE SURFACE LOW SOUTH TO THE COAST OF MAINE. IT WILL
ALSO BE SUPPORTED BY A STRONGER UPPER JET...FORECAST AT 170 KNOTS.
WITH BETTER MOISTURE AND DYNAMICS IN SUPPORT...WE EXPECT A CHANCE OF
SNOW SHOWERS WITH THE FRONT.
MONDAY AND TUESDAY...
HIGH PRESSURE BUILDS OVER THE REGION. THE HIGH THEN MOVES EAST ON
TUESDAY. MILDER AIR MOVES IN ALOFT ON TUESDAY...WHICH SHOULD
SUPPORT INCREASING CLOUDS. THE BEST LIFT WILL BE IN NORTHERN NEW
ENGLAND ON TUESDAY...EXPECT THE BEST CHANCE OF SHOWERS THERE WITH
NEAR NIL POPS HERE IN THE SOUTH.
WEDNESDAY AND THURSDAY...
ANOTHER SURFACE LOW MOVES ACROSS QUEBEC ON WEDNESDAY. SUFFICIENT
MOISTURE IS FORECAST ALOFT TO SUPPORT CLOUDS AND SHOWERS...WITH
TEMPS NORTH OF THE MASS PIKE COLD ENOUGH TO SUPPORT SNOW SHOWERS.
WE WENT WITH CHANCE POPS. THE LOW MOVES OFF THROUGH THE MARITIMES
THURSDAY MAKING ROOM FOR DRY WEATHER. ANOTHER SYSTEM MAY APPROACH
FROM THE WEST TOWARD FRIDAY MORNING...WHICH WILL MEAN INCREASING
CLOUDS THURSDAY NIGHT. AS NOTED ABOVE...A WAVY ZONAL FLOW DOES NOT
INSTIL GREAT CONFIDENCE IN THE TIMING ASSOCIATED WITH THE
WEDNESDAY-THURSDAY FORECAST.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT...
CONDITIONS STARTED THE EVENING WITH MVFR CEILINGS AND MVFR/IFR
VSBYS IN WESTERN AND NORTHERN SECTIONS WITH VFR IN EASTERN MASS
AND RI. THIS IS TRENDING EAST AND NORTHEAST...SO EXPECT CONDITIONS
TO LOWER THROUGH THE NIGHT WITH IFR CEILINGS AFTER MIDNIGHT.
SNOW NORTH OF THE MASS PIKE WILL MIX/CHANGE TO SLEET/FREEZING RAIN
OVERNIGHT. ICE ACCUMULATION POSSIBLE IN FZRA OVER TERMINALS IN TO
THE NW OF THESE HIGHWAYS. LOWER CONFIDENCE IN EXACT TIMING OF IFR
CONDITIONS AND EXACT PLACEMENT OF RAIN/WINTRY MIX LINE. MODERATE
CONFIDENCE.
FRIDAY...
MODERATE CONFIDENCE. MVFR/IFR CONDITIONS PERSIST AS LOW PRES MOVES
OVER THE REGION AND SHIFTS INTO THE GULF OF MAINE. A FEW HOURS OF
FZRA IN NW MA AND SRN NH AFTER 12Z...BUT PRECIP SHOULD BE TRENDING
TOWARD ALL RAIN IN THESE AREAS AS WELL. PRECIP WILL GRADUALLY END
LATE IN THE DAY AND EVENING HOURS WITH CONDITIONS TRANSITIONING TO
VFR LATE. WINDS SHIFTING THE W WITH GUSTS 25 TO 30 KT
POSSIBLE...AND HIGHER GUSTS POSSIBLE OVER THE CAPE AND ISLANDS.
LLWS POSSIBLE DURING THE MORNING.
KBOS TERMINAL...
MODERATE CONFIDENCE. VFR CONTINUES INTO THE EVENING HOURS. AFTER
WHICH EXPECT TREND TO MVFR THEN IFR TONIGHT AS LOW CIGS AND PRECIP
OVERSPREADS THE TERMINAL. MAY BE A BRIEF PERIOD OF MIXED SN/PL
DURING PRECIP ONSET TONIGHT...BUT THIS WILL TRANSITION TO ALL RAIN
AND REMAIN RAIN INTO THE DAY FRI. IFR/MVFR CONDITIONS PERSIST INTO
FRIDAY...BY EVENING PRECIP SHOULD BE COMING TO AN END AND
CONDITIONS LIFT TO VFR. E WINDS TODAY SHIFT TO S TOWARD
MORNING...THEN BECOMING W DURING THE DAY FRI WITH A FEW GUSTS 25
TO 30 KT POSSIBLE DURING THE AFTERNOON AND EVENING.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT...
ANY LINGERING MVFR/IFR SHOULD MOVE OFF TO THE NORTHEAST EARLY...SO
MAINLY VFR CONDITIONS. GUSTY NORTHWEST WINDS WITH POTENTIAL FOR 30
KNOTS. SOME FORECAST INFORMATION SUGGESTS 50-60 KNOT NORTHWESTERS
AT 2000 FEET. IF THIS VERIFIES...IT WOULD MEAN LOW LEVEL WIND SHEAR
FOR THE FIRST PART OF THE NIGHT. HIGH CONFIDENCE ON VFR...MODERATE
CONFIDENCE ON WINDS.
SATURDAY-SUNDAY...
VFR. HIGH CONFIDENCE.
SUNDAY NIGHT-MONDAY...
LOW PRESSURE PASSES ACROSS NORTHERN NEW ENGLAND. THIS WILL BRING
RAIN-SNOW SHOWERS WITH POTENTIAL FOR BRIEF MVFR/IFR CONDITIONS. LOW
TO MODERATE CONFIDENCE.
TUESDAY...
VFR. MODERATE CONFIDENCE.
&&
.MARINE...
TONIGHT...LOW PRESSURE APPROACHES SOUTHERN NEW ENGLAND AND WINDS
AND SEAS WILL INCREASE IN RESPONSE. THIS LOW PRESSURE WILL BRING A
GOOD AMOUNT OF RAIN TO THE AREA DECREASING VISIBILITIES. SMALL
CRAFT ADVISORIES FOR INCREASING SWELL AND GUSTY WINDS AFTER
MIDNIGHT.
FRIDAY...LOW PRES AND SURFACE COLD FRONT WILL MOVE ACROSS THE
WATERS SWITCHING THE SOUTHERLY WINDS TO THE NORTHWEST. PRECIP
SHOULD BE ENDING LATE IN THE DAY. DURING THE DAY GUSTS SHOULD
REMAIN BELOW GALE FORCE. HOWEVER...A FEW GUSTS MAY REACH 34 KT
DURING THE EARLY AFTERNOON. THE BETTER CHANCE FOR GALES WILL BE IN
THE W WINDS LATE IN THE DAY AND OVERNIGHT. GALE WATCH HAS BEEN
ISSUED FOR THIS POTENTIAL. OTHERWISE SMALL CRAFT ADVISORIES STAND
DURING THE DAY TOMORROW.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT...
AS LOW PRESSURE MOVES AWAY FROM NEW ENGLAND...STRONG PRESSURE RISES
WILL BRING INCREASED NORTHWEST WINDS. ENOUGH COLDER AIR WILL MOVE
ACROSS THE WATERS TO BRING WIND GUSTS TO 35 KNOTS. SOME FORECAST
INFORMATION SUGGESTS EVEN STRONGER WINDS AROUND 2000 FEET OFF THE
SURFACE...WHICH COULD BRING WIND GUSTS ABOVE 40 KNOTS. AFTER
CONSIDERING ALL OF THIS...WE HAVE ISSUED A GALE WATCH FOR MOST OF
THE WATERS WITH SMALL CRAFT ADVISORIES FOR ALL REMAINING WATERS.
WINDS SHOULD DIMINISH LATE AT NIGHT.
SATURDAY...
DIMINISHING WINDS AND SEAS AS WEAK HIGH PRESSURE MOVES OVERHEAD.
SEAS OF 5 FEET OR HIGHER SHOULD LINGER OVER SOME OF THE SOUTHERN
WATERS.
SATURDAY NIGHT-SUNDAY...
INCREASING SEAS AND WEST WINDS SATURDAY NIGHT AS LOW PRESSURE PASSES
WELL TO THE NORTH. WINDS AND SEAS SHOULD REACH SMALL CRAFT ADVISORY
CONDITIONS OVER MOST OF THE WATERS FOR A FEW HOURS. WINDS AND SEAS
WILL THEN DIMINISH DURING SUNDAY.
SUNDAY NIGHT-MONDAY...
WINDS INCREASE FROM THE NORTHWEST SUNDAY NIGHT WITH BUILDING SEAS AS
WELL. SMALL CRAFT CONDITIONS ON ALL WATERS POSSIBLE LATE SUNDAY
NIGHT AND MUCH OF MONDAY.
&&
.HYDROLOGY...
A RAPIDLY DEEPENING LOW PRESSURE CENTER WILL APPROACH TONIGHT AND
MOVE DIRECTLY OVER SOUTHERN NEW ENGLAND DURING THE DAY TOMORROW.
INITIALLY PRECIP TYPE WILL BE A WINTERY MIX...WITH ALL AREAS
TRANSITIONING TO ALL RAIN THROUGH THE NIGHT AND INTO THE DAY
TOMORROW. TOTAL QPF VALUES ARE ON THE ORDER OF AN INCH TO A HALF
INCH IN SPOTS. WHILE MOST FFG AND AVAILABLE ENSEMBLE DATA SUGGESTS
THAT FLOODING SHOULD NOT BE AN ISSUE GIVEN THE EXPECTED QPF...THE
FACT THAT THERE IS FROZEN GROUND AND A LITTLE BIT OF REMNANT
SNOWFALL LEFT IN NRN AND WRN PORTIONS OF THE AREA COULD MEAN
BETTER RUNOFF AND ADDITIONAL WATER. HAVE HELD OFF ON A FLOOD WATCH
AT THIS TIME...AS MOST STREAMS/RIVERS SHOULD BE ABLE TO HANDLE
THIS PRECIP. HOWEVER...SOME MINOR NUISANCE FLOODING CAN/T BE RULED
OUT ESPECIALLY EARLY IN THE DAY FRIDAY AS THE HEAVIEST RAINFALL
MOVES THROUGH AND BEST MELTING BEGINS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR CTZ002.
MA...WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR MAZ002>004-
008>011-026.
NH...WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR NHZ011-012-
015.
RI...NONE.
MARINE...GALE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
ANZ231>233-235-237-250-254>256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ231>233-235-
237-250-254>256.
SMALL CRAFT ADVISORY FROM 7 PM FRIDAY TO 7 AM EST SATURDAY FOR
ANZ230-236.
SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR ANZ234-251.
&&
$$
SYNOPSIS...WTB/DOODY
NEAR TERM...DOODY/DUNTEN
SHORT TERM...DOODY
LONG TERM...WTB
AVIATION...WTB/DOODY
MARINE...WTB/DOODY
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
720 PM EST THU JAN 26 2012
.SYNOPSIS...
LOW PRESSURE WILL PUSH ACROSS THE REGION TONIGHT INTO TOMORROW
BRING RAIN ACROSS THE COASTAL REGIONS...AND MIXED PRECIP TO THE
INTERIOR. WEAK HIGH PRESSURE SHOULD BRING COOL BUT SEASONABLE
WEATHER DURING SATURDAY. TWO AREAS OF LOW PRESSURE PASS NORTH OF
SOUTHERN NEW ENGLAND SATURDAY NIGHT AND SUNDAY NIGHT. THE SUNDAY
NIGHT LOW PRESSURE WILL BE MORE SUBSTANTIAL AND BRING A CHANCE OF
RAIN AND SNOW SHOWERS TO OUR AREA. DRY AND SEASONABLY MILD WEATHER
RETURNS DURING NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
7 PM UPDATE...
PRECIP HAS STARTED OVER MOST OF THE FORECAST AREA. OBSERVATIONS
REPORT PTYPE AS RAIN SOUTH OF THE MASS PIKE WITH SNOW TO THE
NORTH. CEF REPORTED SLEET AT 6 PM. PVD INITIATED WITH LIGHT SLEET
BUT QUICKLY CHANGED TO LIGHT RAIN.
PCPN THAT BEGAN AS SNOW IN THE SPRINGFIELD AREA CHANGED TO RAIN
AFTER 3 HOURS. WITH WARM AIR MOVING NORTH OVERNIGHT WE EXPECT THIS
CHANGEOVER TO SHIFT NORTH WITH TIME. THE AFTERNOON MODELS SHOWED A
30-40 KNOT AGEOSTROPIC DRAINAGE WIND INTO SOUTHWEST NH AND
NORTHWEST MASS...SO DIGGING OUT THE COLD SURFACE AIR WILL BE A
CHORE OVERNIGHT AND EARLY FRIDAY.
THE UPDATE INCLUDES ADJUSTMENTS TO TEMPS AND DEWPOINTS BASED ON
OBSERVATION. WE HAVE ALSO LOADED THE HRRR WINDS THROUGH 06Z AS
THESE BEST REFLECTED THE WIND DIRECTION CHANGE AT BOS.
PREVIOUS DISCUSSION...
NEW TEMP COLUMN DATA STILL SUPPORTS INITIAL MIX OF SN/PL/FZRA
ACROSS THE INTERIOR AS ISENTROPIC LIFT STRENGTHENS WITH THE WARM
FROPA. LLVL WARM AIR WILL BE QUICKEST TO REACH AREAS S OF THE MA
PIKE AS WELL AS WITHIN THE I-495 CORRIDOR. EXPECTING THESE
AREAS...AFTER A BRIEF PERIOD OF PL/SN/RA...TO QUICKLY TRANSITION
TO ALL RAIN ESPECIALLY AFTER MIDNIGHT. OUTSIDE OF THESE AREAS /N
CENTRAL AND WRN MA...N CENTRAL CT...AND SRN NH/ A PERIOD OF EVAP
COOLING AND NORMAL DIURNAL COOLING WILL ALLOW SOME PL/SN TO START
PRECIP THIS EVENING. GIVEN THESE COOLING FACTORS...2M TEMPS WILL
BE SLOW TO RISE OVERNIGHT...SO AS LOW TO MID LVLS OF THE COLUMN
RAPIDLY WARM WITH THE FRONT ALOFT...RAIN WILL BEGIN TO FALL ONTO A
NEAR 0C SURFACE. THEREFORE...SOME ICE ACCUMULATION REMAINS LIKELY
IN THESE AREAS. QPF VALUES OVERNIGHT RANGE 0.25 TO 0.5 INCHES.
GIVEN TEMPS ICE ACCUMULATIONS OF A QUARTER TO EVEN A THIRD OF AN
INCH ARE POSSIBLE...WITH THE HIGHEST AMOUNTS IN SRN NH...WHICH
WILL REMAIN NEAR FREEZING FOR THE LONGEST PERIOD OF TIME. IT
SHOULD BE NOTED THAT EXACT TIMING OF TRANSITION IS SOMEWHAT
UNCERTAIN AS IT WILL DEPEND STRONGLY ON THE QUICKNESS OF THE WARM
AIR AND THE ROBUSTNESS OF THE INITIAL COOLING/SNOWFALL. LATEST
GUIDANCE 2M TEMPS ARE ALSO A BIT WARMER THAN PREVIOUS FORECAST.
PLEASE STAY TUNED TO WINTER WEATHER ADVISORY UPDATES AS THEY COME
OUT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
LLVL WARM FRONT WILL BE PUSHING N OF THE MA PIKE THROUGH THE
MORNING HOURS BASED ON LATEST GUIDANCE TIMING. THEREFORE...ANY
AREAS OF SOUTHERN NEW ENGLAND S OF THE MASS PIKE AND IMMEDIATELY
TO THE N SHOULD BE TRANSITIONING TO ALL RAIN. BEFORE PRECIP
BECOMES ALL RAIN...A BIT MORE ICE ACCUMULATION IS POSSIBLE IN THE
AFOREMENTIONED AREAS SINCE A FEW HOURS OF FZRA ARE POSSIBLE
THROUGH AT LEAST THE MID MORNING HOURS...ESPECIALLY IN SRN NH. THE
DEEPENING LOW PRES ASSOCIATED WITH THE FRONT WILL BE MOVING ALMOST
DIRECTLY OVER THE AREA FROM SW TO NE DURING THE AFTERNOON HOURS.
THEREFORE...ONCE THE LOW SHIFTS E AND CAA COMMENCES ON THE BACK
SIDE LATE IN THE DAY...ALL PRECIP SHOULD BE GRADUALLY COMING TO AN
END FROM W TO E. H92 TEMPS WITHIN THE WARM LAYER REACH AROUND +12C
ALONG SRN PORTIONS OF THE FA...SO TEMPS REACHING INTO THE 50S ARE
LIKELY WHILE NRN AREAS REMAIN IN THE 40S.
GIVEN THE RAPIDLY DEEPENING LOW WITH PRES CHANGES OF 1 TO 2MB PER
HOUR...ISALLOBARIC FLOW WILL BE QUITE STRONG BOTH JUST AHEAD AND
QUITE STRONG WITH EQUAL RISES BEHIND THE EXITING LOW. BOTH NAM/GFS
SHOW A NEAR 60 KT H92 LLJ CLIPPING THE SRN TIER DURING THE 12Z-
18Z PERIOD. HOWEVER...DESPITE THESE DYNAMIC FACTORS...A STRONG
INVERSION WILL BE IN PLACE GIVEN THAT UPPER LVL WARM FRONT MOVES
WELL AHEAD OF THE LLVL FRONT. SO ATTM...NOT EXPECTING MUCH MIXING
WITH THIS INITIAL JET. HOWEVER...STRONG SFC PRES CHANGES DO
SUGGEST THAT SUSTAINED WINDS MAY COME CLOSE TO THE 27 KT ADVISORY
THRESHOLD OVER THE CAPE/ISLANDS/S COAST BOTH DURING THE MORNING
JET PASSAGE AND MUCH LATER IN THE EVENING AS THE LOW MOVES E AND
CAA COMMENCES...AND A *FEW* RAW MODEL OUTPUTS SUPPORT THIS. GIVEN
THE STRONG MITIGATING FACTORS /STRONG INVERSION/ AND PRES RISES NOT
EXCEEDING THE 2MB PER HOUR THAT MOST OFTEN ACCOMPANIES STRONG
WINDS...HAVE HELD OFF ON WIND HEADLINES FOR THIS UPDATE.
HOWEVER...THIS WILL NEED TO BE MONITORED DURING FUTURE UPDATES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
BIG PICTURE...
HUDSON BAY UPPER LOW CARVES A BROAD UPPER TROUGH OVER THE EASTERN
USA DURING THE WEEKEND AND EARLY NEXT WEEK. THE FLOW THEN BECOMES
MORE ZONAL FOR MIDWEEK. THUS EXPECT A COOLING TREND OVER THE
WEEKEND FOLLOWED BY A TREND BACK TO SEASONABLY MILD TEMPS DURING
NEXT WEEK.
ONE SHORTWAVE PASSES ACROSS CANADA SATURDAY NIGHT WITH MOST OF THE
SUPPORT AND MOISTURE REMAINING NORTH OF US. ANOTHER RUNS THROUGH
THE BASE OF THE UPPER TROUGH SUNDAY NIGHT. A THIRD WAVE PASSES
NORTH OF US ON WEDNESDAY...ALTHOUGH WITH A ZONAL FLOW THE TIMING ON
THIS PASSAGE IS LOW CONFIDENCE.
THE WEEKEND FORECAST DRAWS FROM A MIX OF MOS DATA. THE LONGER TERM
FORECAST DRAWS FROM THE 12Z ECMWF AND HPC GRIDDED VALUES.
FRIDAY NIGHT...
PRESSURE RISES TRAILING THE GULF OF MAINE SURFACE LOW WILL BE 1-2
MB/HOUR. THIS SHOULD SUPPORT A BLUSTERY NW WIND OVERNIGHT. THE NAM
SHOWS SUFFICIENT COOLING ALOFT TO SUPPORT 30 KNOT GUSTS. THE GFS
SHOWS 50-60 KNOT WINDS AT 900-950 MB...BUT LAPSE RATES LESS THAN
5C/KM AND SO MORE QUESTIONABLE MIXING. THE BEST CHANCE FOR MIXING
STRONG WINDS TO THE SURFACE WOULD BE OVER THE CAPE AND ISLANDS...AND
POSSIBLY ACROSS THE HILLTOPS. FOR NOW WE HAVE GONE WITH LAND GUSTS
25-30 KNOTS. WINDS SHOULD DIMINISH OVERNIGHT AS THE SURFACE LOW
MOVES FARTHER AWAY.
SATURDAY...
WEAK OFFSHORE HIGH BUILDS OVER THE FORECAST AREA AND THEN OFF TO THE
EAST IN THE AFTERNOON. LOW PRESSURE MOVING ACROSS CANADA SWINGS A
FRONT THROUGH THE REGION SATURDAY EVENING. LIMITED MOISTURE WITH
THIS SYSTEM...WITH MODELS INDICATING MOST OF THE MOISTURE OVER US
WILL BE AT MID LEVELS. BEST CHANCE OF PCPN WILL BE IN NORTHERN NEW
ENGLAND CLOSER TO THE TRACK OF THE LOW. EXPECT INCREASING CLOUDS
AFTERNOON AND EVENING AS THE FRONT APPROACHES...THEN CLEARING
SATURDAY NIGHT...AND NO POPS.
SUNDAY...
ANOTHER SHORTWAVE APPROACHES SIMILAR TO SATURDAY. THIS ONE IS
PROJECTED TO HAVE MORE MOISTURE ALOFT...AND A MORE SOUTHERLY TRACK
THAT WILL DRAW THE SURFACE LOW SOUTH TO THE COAST OF MAINE. IT WILL
ALSO BE SUPPORTED BY A STRONGER UPPER JET...FORECAST AT 170 KNOTS.
WITH BETTER MOISTURE AND DYNAMICS IN SUPPORT...WE EXPECT A CHANCE OF
SNOW SHOWERS WITH THE FRONT.
MONDAY AND TUESDAY...
HIGH PRESSURE BUILDS OVER THE REGION. THE HIGH THEN MOVES EAST ON
TUESDAY. MILDER AIR MOVES IN ALOFT ON TUESDAY...WHICH SHOULD
SUPPORT INCREASING CLOUDS. THE BEST LIFT WILL BE IN NORTHERN NEW
ENGLAND ON TUESDAY...EXPECT THE BEST CHANCE OF SHOWERS THERE WITH
NEAR NIL POPS HERE IN THE SOUTH.
WEDNESDAY AND THURSDAY...
ANOTHER SURFACE LOW MOVES ACROSS QUEBEC ON WEDNESDAY. SUFFICIENT
MOISTURE IS FORECAST ALOFT TO SUPPORT CLOUDS AND SHOWERS...WITH
TEMPS NORTH OF THE MASS PIKE COLD ENOUGH TO SUPPORT SNOW SHOWERS.
WE WENT WITH CHANCE POPS. THE LOW MOVES OFF THROUGH THE MARITIMES
THURSDAY MAKING ROOM FOR DRY WEATHER. ANOTHER SYSTEM MAY APPROACH
FROM THE WEST TOWARD FRIDAY MORNING...WHICH WILL MEAN INCREASING
CLOUDS THURSDAY NIGHT. AS NOTED ABOVE...A WAVY ZONAL FLOW DOES NOT
INSTIL GREAT CONFIDENCE IN THE TIMING ASSOCIATED WITH THE
WEDNESDAY-THURSDAY FORECAST.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT...
CONDITIONS STARTED THE EVENING WITH MVFR CEILINGS AND MVFR/IFR
VSBYS IN WESTERN AND NORTHERN SECTIONS WITH VFR IN EASTERN MASS
AND RI. THIS IS TRENDING EAST AND NORTHEAST...SO EXPECT CONDITIONS
TO LOWER THROUGH THE NIGHT WITH IFR CEILINGS AFTER MIDNIGHT.
SNOW NORTH OF THE MASS PIKE WILL MIX/CHANGE TO SLEET/FREEZING RAIN
OVERNIGHT. ICE ACCUMULATION POSSIBLE IN FZRA OVER TERMINALS IN TO
THE NW OF THESE HIGHWAYS. LOWER CONFIDENCE IN EXACT TIMING OF IFR
CONDITIONS AND EXACT PLACEMENT OF RAIN/WINTRY MIX LINE. MODERATE
CONFIDENCE.
FRIDAY...
MODERATE CONFIDENCE. MVFR/IFR CONDITIONS PERSIST AS LOW PRES MOVES
OVER THE REGION AND SHIFTS INTO THE GULF OF MAINE. A FEW HOURS OF
FZRA IN NW MA AND SRN NH AFTER 12Z...BUT PRECIP SHOULD BE TRENDING
TOWARD ALL RAIN IN THESE AREAS AS WELL. PRECIP WILL GRADUALLY END
LATE IN THE DAY AND EVENING HOURS WITH CONDITIONS TRANSITIONING TO
VFR LATE. WINDS SHIFTING THE W WITH GUSTS 25 TO 30 KT
POSSIBLE...AND HIGHER GUSTS POSSIBLE OVER THE CAPE AND ISLANDS.
LLWS POSSIBLE DURING THE MORNING.
KBOS TERMINAL...
MODERATE CONFIDENCE. VFR CONTINUES INTO THE EVENING HOURS. AFTER
WHICH EXPECT TREND TO MVFR THEN IFR TONIGHT AS LOW CIGS AND PRECIP
OVERSPREADS THE TERMINAL. MAY BE A BRIEF PERIOD OF MIXED SN/PL
DURING PRECIP ONSET TONIGHT...BUT THIS WILL TRANSITION TO ALL RAIN
AND REMAIN RAIN INTO THE DAY FRI. IFR/MVFR CONDITIONS PERSIST INTO
FRIDAY...BY EVENING PRECIP SHOULD BE COMING TO AN END AND
CONDITIONS LIFT TO VFR. E WINDS TODAY SHIFT TO S TOWARD
MORNING...THEN BECOMING W DURING THE DAY FRI WITH A FEW GUSTS 25
TO 30 KT POSSIBLE DURING THE AFTERNOON AND EVENING.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT...
ANY LINGERING MVFR/IFR SHOULD MOVE OFF TO THE NORTHEAST EARLY...SO
MAINLY VFR CONDITIONS. GUSTY NORTHWEST WINDS WITH POTENTIAL FOR 30
KNOTS. SOME FORECAST INFORMATION SUGGESTS 50-60 KNOT NORTHWESTERS
AT 2000 FEET. IF THIS VERIFIES...IT WOULD MEAN LOW LEVEL WIND SHEAR
FOR THE FIRST PART OF THE NIGHT. HIGH CONFIDENCE ON VFR...MODERATE
CONFIDENCE ON WINDS.
SATURDAY-SUNDAY...
VFR. HIGH CONFIDENCE.
SUNDAY NIGHT-MONDAY...
LOW PRESSURE PASSES ACROSS NORTHERN NEW ENGLAND. THIS WILL BRING
RAIN-SNOW SHOWERS WITH POTENTIAL FOR BRIEF MVFR/IFR CONDITIONS. LOW
TO MODERATE CONFIDENCE.
TUESDAY...
VFR. MODERATE CONFIDENCE.
&&
.MARINE...
TONIGHT...LOW PRESSURE APPROACHES SOUTHERN NEW ENGLAND AND WINDS
AND SEAS WILL INCREASE IN RESPONSE. THIS LOW PRESSURE WILL BRING A
GOOD AMOUNT OF RAIN TO THE AREA DECREASING VISIBILITIES. SMALL
CRAFT ADVISORIES FOR INCREASING SWELL AND GUSTY WINDS AFTER
MIDNIGHT.
FRIDAY...LOW PRES AND SURFACE COLD FRONT WILL MOVE ACROSS THE
WATERS SWITCHING THE SOUTHERLY WINDS TO THE NORTHWEST. PRECIP
SHOULD BE ENDING LATE IN THE DAY. DURING THE DAY GUSTS SHOULD
REMAIN BELOW GALE FORCE. HOWEVER...A FEW GUSTS MAY REACH 34 KT
DURING THE EARLY AFTERNOON. THE BETTER CHANCE FOR GALES WILL BE IN
THE W WINDS LATE IN THE DAY AND OVERNIGHT. GALE WATCH HAS BEEN
ISSUED FOR THIS POTENTIAL. OTHERWISE SMALL CRAFT ADVISORIES STAND
DURING THE DAY TOMORROW.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT...
AS LOW PRESSURE MOVES AWAY FROM NEW ENGLAND...STRONG PRESSURE RISES
WILL BRING INCREASED NORTHWEST WINDS. ENOUGH COLDER AIR WILL MOVE
ACROSS THE WATERS TO BRING WIND GUSTS TO 35 KNOTS. SOME FORECAST
INFORMATION SUGGESTS EVEN STRONGER WINDS AROUND 2000 FEET OFF THE
SURFACE...WHICH COULD BRING WIND GUSTS ABOVE 40 KNOTS. AFTER
CONSIDERING ALL OF THIS...WE HAVE ISSUED A GALE WATCH FOR MOST OF
THE WATERS WITH SMALL CRAFT ADVISORIES FOR ALL REMAINING WATERS.
WINDS SHOULD DIMINISH LATE AT NIGHT.
SATURDAY...
DIMINISHING WINDS AND SEAS AS WEAK HIGH PRESSURE MOVES OVERHEAD.
SEAS OF 5 FEET OR HIGHER SHOULD LINGER OVER SOME OF THE SOUTHERN
WATERS.
SATURDAY NIGHT-SUNDAY...
INCREASING SEAS AND WEST WINDS SATURDAY NIGHT AS LOW PRESSURE PASSES
WELL TO THE NORTH. WINDS AND SEAS SHOULD REACH SMALL CRAFT ADVISORY
CONDITIONS OVER MOST OF THE WATERS FOR A FEW HOURS. WINDS AND SEAS
WILL THEN DIMINISH DURING SUNDAY.
SUNDAY NIGHT-MONDAY...
WINDS INCREASE FROM THE NORTHWEST SUNDAY NIGHT WITH BUILDING SEAS AS
WELL. SMALL CRAFT CONDITIONS ON ALL WATERS POSSIBLE LATE SUNDAY
NIGHT AND MUCH OF MONDAY.
&&
.HYDROLOGY...
A RAPIDLY DEEPENING LOW PRESSURE CENTER WILL APPROACH TONIGHT AND
MOVE DIRECTLY OVER SOUTHERN NEW ENGLAND DURING THE DAY TOMORROW.
INITIALLY PRECIP TYPE WILL BE A WINTERY MIX...WITH ALL AREAS
TRANSITIONING TO ALL RAIN THROUGH THE NIGHT AND INTO THE DAY
TOMORROW. TOTAL QPF VALUES ARE ON THE ORDER OF AN INCH TO A HALF
INCH IN SPOTS. WHILE MOST FFG AND AVAILABLE ENSEMBLE DATA SUGGESTS
THAT FLOODING SHOULD NOT BE AN ISSUE GIVEN THE EXPECTED QPF...THE
FACT THAT THERE IS FROZEN GROUND AND A LITTLE BIT OF REMNANT
SNOWFALL LEFT IN NRN AND WRN PORTIONS OF THE AREA COULD MEAN
BETTER RUNOFF AND ADDITIONAL WATER. HAVE HELD OFF ON A FLOOD WATCH
AT THIS TIME...AS MOST STREAMS/RIVERS SHOULD BE ABLE TO HANDLE
THIS PRECIP. HOWEVER...SOME MINOR NUISANCE FLOODING CAN/T BE RULED
OUT ESPECIALLY EARLY IN THE DAY FRIDAY AS THE HEAVIEST RAINFALL
MOVES THROUGH AND BEST MELTING BEGINS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR CTZ002.
MA...WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR MAZ002>004-
008>011-026.
NH...WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR NHZ011-012-
015.
RI...NONE.
MARINE...GALE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
ANZ231>233-235-237-250-254>256.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 PM EST FRIDAY FOR
ANZ231>233-235-237-250-254>256.
SMALL CRAFT ADVISORY FROM 7 PM FRIDAY TO 7 AM EST SATURDAY FOR
ANZ230-236.
SMALL CRAFT ADVISORY FROM 1 AM FRIDAY TO 7 AM EST SATURDAY FOR
ANZ234-251.
&&
$$
SYNOPSIS...WTB/DOODY
NEAR TERM...DOODY
SHORT TERM...DOODY
LONG TERM...WTB
AVIATION...WTB/DOODY
MARINE...WTB/DOODY
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
634 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE CURRENTLY ACROSS THE REGION WILL MOVE OFF THE COAST
THIS EVENING. A WARM FRONT LIFT NORTH ACROSS THE AREA TONIGHT...
BRINGING INCREASING MOISTURE. A LOW PRESSURE SYSTEM WILL AFFECT
THE AREA THURSDAY INTO FRIDAY. DRY HIGH PRESSURE WILL TAKE CONTROL
FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINGERING LOW LEVEL MOISTURE HAS ALLOWED AREAS OF FOG TO DEVELOP
ACROSS THE MIDLANDS THIS MORNING. THE AREA OF FOG/STRATUS HAS
MOVED INTO THE CENTRAL MIDLANDS. HAVE CANCELLED THE DENSE FOG
ADVISORY FOR THE NORTHERN MIDLANDS.
THE RUC AND NAM20 MODELS INDICATE THE LOW LEVEL MOISTURE TO
LINGER THROUGH THE 12Z-14Z TIME-FRAME. HOWEVER..BOTH MODELS SHOW
A LOW LEVEL JET WHICH PROMOTE MIXING.
HIGH PRESSURE CENTERED OVER THE OH RIVER VALLEY WILL MOVE EAST TO
THE MID ATLANTIC COAST THROUGH THE EVENING. WEAK UPPER LEVEL
RIDGING WILL ALSO BUILD ACROSS THE SOUTHEASTERN STATES. WE WILL
SEE PARTLY TO MOSTLY SUNNY SKIES TODAY WITH HIGHS IN THE MID 60S
NORTH TO AROUND 70 SOUTH. MORE CLOUDINESS IS EXPECTED TONIGHT AS
THE UPPER LEVEL RIDGE MOVES OFF THE EAST COAST AND A WARM FRONT
CROSSES THE AREA FROM THE SOUTH. INCREASING CLOUDS WILL HELP TO
HOLD TEMPERATURES UP OVERNIGHT...WITH LOWS IN THE MID 40S TO LOWER
50S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AN UPSTREAM UPPER LEVEL CUTOFF LOW CURRENTLY OVER NEW MEXICO WILL
SLOWLY PUSH EASTWARD ACROSS THE SOUTHERN PART OF THE COUNTRY
THURSDAY...THEN OPEN UP AND LIFT ACROSS THE SOUTHEASTERN STATES
FRIDAY.
WEAK ISENTROPIC LIFTING DEVELOPS IN WARM ADVECTION DURING THE DAY
THURSDAY. KEPT A MENTION OF SLIGHT CHANCE POPS FOR THURSDAY...MAINLY
ACROSS THE WESTERN HALF OF THE FORECAST AREA.
THE ECMWF IS THE MOST PROGRESSIVE WITH THE NAM BEING SLIGHTLY LOWER
AND THE GFS BEING THE SLOWEST OF ALL GUIDANCE. DISCOUNTED THE GFS
SOLUTION AT THIS TIME GIVEN ITS LARGE CHANGE FROM PREVIOUS RUNS
AND AS IT IS AN OUTLIER AMONG ALL GUIDANCE AND LEANING TOWARDS THE
NAM TIMING. KEPT INCREASING POPS THURSDAY NIGHT WITH CATEGORICAL
POPS EARLY FRIDAY...AND DIMINISHING POPS ON FRIDAY AFTERNOON.
THUNDER IS POSSIBLE GIVEN MARGINAL INSTABILITY. RAINFALL AMOUNTS
ARE EXPECTED TO RANGE BETWEEN 0.25 AND 0.50 INCH.
TEMPERATURES ON THURSDAY WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE
70S AND OVERNIGHT LOWS IN THE UPPER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED FORECAST FEATURES DRY WEATHER WITH NEAR TO SLIGHTLY
BELOW NORMAL TEMPERATURES OVER THE WEEKEND...FOLLOWED BY A WEAK
WARMING TREND ON TUESDAY.
ANOTHER UPPER TROUGH AND ACCOMPANYING SURFACE COLD FRONT WILL PUSH
THROUGH THE OH/TN VALLEYS ON SATURDAY AND SHIFT OFF THE COAST BY
SUNDAY. THERE WILL BE LITTLE MOISTURE AVAILABLE FOR THE QUICK
MOVING TROUGH TO WORK WITH AS PRECIPITABLE WATER VALUES WILL BE
AROUND A HALF INCH SATURDAY AND FALL BELOW A QUARTER INCH ON SUNDAY.
A QUICK REINFORCING SHOT OF COLD AIR WILL ARRIVE FOR SUNDAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE AS THE UPPER TROUGH AXIS PASSES
OVERHEAD.
TEMPERATURES ON SATURDAY WILL RANGE FROM THE UPPER 50S NORTHERN
MIDLANDS TO LOWER 60S IN THE EASTERN MIDLANDS AND CSRA. SATURDAY
NIGHT UNDER COLD ADVECTION OVERNIGHT LOWS WILL FALL INTO THE LOWER
AND MID 30S AS HIGH PRESSURE BUILDS INTO THE REGION. SUNDAY LOOKS
TO BE THE COLDEST DAY DESPITE PLENTY OF SUNSHINE WITH HIGHS SLIGHTLY
BELOW NORMAL IN THE 50S AND A COLD NIGHT IS EXPECTED SUNDAY NIGHT
WITH HIGH PRESSURE CENTERED OVER THE FORECAST AREA. SUNDAY NIGHT
LOWS SHOULD FALL INTO THE 20S.
EARLY NEXT WEEK THE MID LEVEL FLOW BECOMES MORE ZONAL AND A
DAMPENING TROUGH MOVING THROUGH THE FLOW WILL PASS OVER THE AREA ON
TUESDAY. WILL KEEP A DRY FORECAST AT THIS TIME GIVEN UNCERTAINTY ON
DAY 7...BUT TEMPERATURES WILL REBOUND AND WARM AS SOUTHERLY FLOW
RETURNS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
INITIAL SHORT WAVE DEPICTED IN THE VORTICITY FIELD OVER GEORGIA WILL
CROSS THE REGION THIS MORNING. HIGH PRESSURE WILL RETREAT
NORTHEAST AHEAD OF IT ALLOWING A FLOW OF MORE MOIST AIR FROM THE
SOUTHWEST TO FLOW ACROSS THE AREA BEHIND THE SHORT WAVE. PATCHY
LOW STRATUS AND FOG SHOULD DISSIPATE EARLY THIS MORNING WITH VFR
CONDITIONS RETURNING...BUT AS THAT SHORTWAVE MOVES NORTHEAST OF THE
AREA...CLOUDINESS WILL INCREASE DURING THE DAY AND CEILINGS WILL
LOWER AGAIN AS THE MOISTURE BUILDS INTO THE LOWER LEVELS. ALL
MODEL GUIDANCE IS SIMILAR IN INCREASING CLOUDINESS AND DROPPING
THE CEILINGS AND VISIBILITY LATER TONIGHT. IFR CONDITIONS ARE
POSSIBLE ACROSS THE AREA BY THURSDAY MORNING...BUT CONFIDENCE IS
TOO LOW TO INCLUDE IT IN THE TERMINAL FORECASTS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...IFR CONDITIONS ARE POSSIBLE FROM THURSDAY
MORNING THROUGH FRIDAY MORNING AS A STORM SYSTEM CURRENTLY OVER
NORTHERN MEXICO MOVES TOWARD THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
632 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA TODAY WILL MOVE OFF THE COAST TONIGHT.
A LOW PRESSURE SYSTEM WILL AFFECT THE AREA THURSDAY INTO FRIDAY.
DRY HIGH PRESSURE WILL TAKE CONTROL FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINGERING LOW LEVEL MOISTURE HAS ALLOWED AREAS OF FOG TO DEVELOP
ACROSS THE MIDLANDS EARLY THIS MORNING. IT APPEARS THE LARGEST
AREA IS AFFECTING THE NORTH MIDLANDS. THE RUC AND NAM20 MODELS
INDICATE THE LOW LEVEL MOISTURE TO LINGER THROUGH THE 12Z-14Z
TIME-FRAME. HOWEVER..BOTH MODELS SHOW A LOW LEVEL JET WHICH PROMOTE
MIXING. SO...NOT WE ARE NOT EXPECTING THE FOG TO BE AS
WIDESPREAD AS TUESDAY MORNING. WILL CONTINUE THE DENSE FOG
ADVISORY FOR LANCASTER AND CHESTERFIELD COUNTIES THROUGH 7 AM...
AND ADD AREAS OF FOG TO OTHER SECTIONS OF THE MIDLANDS. THE FOG
HIGH PRESSURE CENTERED OVER THE OH RIVER VALLEY WILL MOVE EAST TO
THE MID ATLANTIC COAST THROUGH THE EVENING. WEAK UPPER LEVEL
RIDGING WILL ALSO BUILD ACROSS THE SOUTHEASTERN STATES. WE WILL
SEE PARTLY TO MOSTLY SUNNY SKIES TODAY WITH HIGHS IN THE MID 60S
NORTH TO AROUND 70 SOUTH. MORE CLOUDINESS IS EXPECTED TONIGHT AS
THE UPPER LEVEL RIDGE MOVES OFF THE EAST COAST AND A SOUTHWEST
FLOW ALOFT BRINGS IN MORE MOISTURE. CLOUDS WILL HELP TO HOLD
TEMPERATURES UP OVERNIGHT...WITH LOWS IN THE MID 40S TO LOWER 50S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AN UPSTREAM UPPER LEVEL CUTOFF LOW CURRENTLY OVER NEW MEXICO WILL
SLOWLY PUSH EASTWARD ACROSS THE SOUTHERN PART OF THE COUNTRY
THURSDAY...THEN OPEN UP AND LIFT ACROSS THE SOUTHEASTERN STATES
FRIDAY.
WEAK ISENTROPIC LIFTING DEVELOPS IN WARM ADVECTION DURING THE DAY
THURSDAY. KEPT A MENTION OF SLIGHT CHANCE POPS FOR THURSDAY...MAINLY
ACROSS THE WESTERN HALF OF THE FORECAST AREA.
THE ECMWF IS THE MOST PROGRESSIVE WITH THE NAM BEING A BIT SLOWER
AND THE GFS BEING THE SLOWEST OF ALL GUIDANCE. DISCOUNTED THE GFS
SOLUTION AT THIS TIME GIVEN ITS LARGE CHANGE FROM PREVIOUS RUNS
AND AS IT IS AN OUTLIER AMONG ALL GUIDANCE AND LEANING TOWARDS THE
NAM TIMING. KEPT INCREASING POPS THURSDAY NIGHT WITH CATEGORICAL
POPS EARLY FRIDAY...AND DIMINISHING POPS ON FRIDAY AFTERNOON.
THUNDER IS POSSIBLE GIVEN MARGINAL INSTABILITY.
TEMPERATURES ON THURSDAY WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE
70S AND OVERNIGHT LOWS IN THE UPPER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED FORECAST FEATURES DRY WEATHER WITH NEAR TO SLIGHTLY
BELOW NORMAL TEMPERATURES OVER THE WEEKEND...FOLLOWED BY A WEAK
WARMING TREND ON TUESDAY.
ANOTHER UPPER TROUGH AND ACCOMPANYING SURFACE COLD FRONT WILL PUSH
THROUGH THE OH/TN VALLEYS ON SATURDAY AND SHIFT OFF THE COAST BY
SUNDAY. THERE WILL BE LITTLE MOISTURE AVAILABLE FOR THE QUICK
MOVING TROUGH TO WORK WITH AS PRECIPITABLE WATER VALUES WILL BE
AROUND A HALF INCH SATURDAY AND FALL BELOW A QUARTER INCH ON SUNDAY.
A QUICK REINFORCING SHOT OF COLD AIR WILL ARRIVE FOR SUNDAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE AS THE UPPER TROUGH AXIS PASSES
OVERHEAD.
TEMPERATURES ON SATURDAY WILL RANGE FROM THE UPPER 50S NORTHERN
MIDLANDS TO LOWER 60S IN THE EASTERN MIDLANDS AND CSRA. SATURDAY
NIGHT UNDER COLD ADVECTION OVERNIGHT LOWS WILL FALL INTO THE LOWER
AND MID 30S AS HIGH PRESSURE BUILDS INTO THE REGION. SUNDAY LOOKS
TO BE THE COLDEST DAY DESPITE PLENTY OF SUNSHINE WITH HIGHS SLIGHTLY
BELOW NORMAL IN THE 50S AND A COLD NIGHT IS EXPECTED SUNDAY NIGHT
WITH HIGH PRESSURE CENTERED OVER THE FORECAST AREA. SUNDAY NIGHT
LOWS SHOULD FALL INTO THE 20S.
EARLY NEXT WEEK THE MID LEVEL FLOW BECOMES MORE ZONAL AND A
DAMPENING TROUGH MOVING THROUGH THE FLOW WILL PASS OVER THE AREA ON
TUESDAY. WILL KEEP A DRY FORECAST AT THIS TIME GIVEN UNCERTAINTY ON
DAY 7...BUT TEMPERATURES WILL REBOUND AND WARM AS SOUTHERLY FLOW
RETURNS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
INITIAL SHORT WAVE DEPICTED IN THE VORTICITY FIELD OVER GEORGIA WILL
CROSS THE REGION THIS MORNING. HIGH PRESSURE WILL RETREAT
NORTHEAST AHEAD OF IT ALLOWING A FLOW OF MORE MOIST AIR FROM THE
SOUTHWEST TO FLOW ACROSS THE AREA BEHIND THE SHORT WAVE. PATCHY
LOW STRATUS AND FOG SHOULD DISSIPATE EARLY THIS MORNING WITH VFR
CONDITIONS RETURNING...BUT AS THAT SHORTWAVE MOVES NORTHEAST OF THE
AREA...CLOUDINESS WILL INCREASE DURING THE DAY AND CEILINGS WILL
LOWER AGAIN AS THE MOISTURE BUILDS INTO THE LOWER LEVELS. ALL
MODEL GUIDANCE IS SIMILAR IN INCREASING CLOUDINESS AND DROPPING
THE CEILINGS AND VISIBILITY LATER TONIGHT. IFR CONDITIONS ARE
POSSIBLE ACROSS THE AREA BY THURSDAY MORNING...BUT CONFIDENCE IS
TOO LOW TO INCLUDE IT IN THE TERMINAL FORECASTS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...IFR CONDITIONS ARE POSSIBLE FROM THURSDAY
MORNING THROUGH FRIDAY MORNING AS A STORM SYSTEM CURRENTLY OVER
NORTHERN MEXICO MOVES TOWARD THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
359 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA TODAY WILL MOVE OFF THE COAST TONIGHT.
A LOW PRESSURE SYSTEM WILL AFFECT THE AREA THURSDAY INTO FRIDAY.
DRY HIGH PRESSURE WILL TAKE CONTROL FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINGERING LOW LEVEL MOISTURE HAS ALLOWED AREAS OF FOG TO DEVELOP
ACROSS THE MIDLANDS EARLY THIS MORNING. IT APPEARS THE LARGEST
AREA IS AFFECTING THE NORTH MIDLANDS. THE RUC AND NAM20 MODELS
INDICATE THE LOW LEVEL MOISTURE TO LINGER THROUGH THE 12Z-14Z
TIME-FRAME. HOWEVER..BOTH MODELS SHOW A LOW LEVEL JET WHICH PROMOTE
MIXING. SO...NOT WE ARE NOT EXPECTING THE FOG TO BE AS
WIDESPREAD AS TUESDAY MORNING. WILL CONTINUE THE DENSE FOG
ADVISORY FOR LANCASTER AND CHESTERFIELD COUNTIES THROUGH 7 AM...
AND ADD AREAS OF FOG TO OTHER SECTIONS OF THE MIDLANDS. THE FOG
HIGH PRESSURE CENTERED OVER THE OH RIVER VALLEY WILL MOVE EAST TO
THE MID ATLANTIC COAST THROUGH THE EVENING. WEAK UPPER LEVEL
RIDGING WILL ALSO BUILD ACROSS THE SOUTHEASTERN STATES. WE WILL
SEE PARTLY TO MOSTLY SUNNY SKIES TODAY WITH HIGHS IN THE MID 60S
NORTH TO AROUND 70 SOUTH. MORE CLOUDINESS IS EXPECTED TONIGHT AS
THE UPPER LEVEL RIDGE MOVES OFF THE EAST COAST AND A SOUTHWEST
FLOW ALOFT BRINGS IN MORE MOISTURE. CLOUDS WILL HELP TO HOLD
TEMPERATURES UP OVERNIGHT...WITH LOWS IN THE MID 40S TO LOWER 50S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AN UPSTREAM UPPER LEVEL CUTOFF LOW CURRENTLY OVER NEW MEXICO WILL
SLOWLY PUSH EASTWARD ACROSS THE SOUTHERN PART OF THE COUNTRY
THURSDAY...THEN OPEN UP AND LIFT ACROSS THE SOUTHEASTERN STATES
FRIDAY.
WEAK ISENTROPIC LIFTING DEVELOPS IN WARM ADVECTION DURING THE DAY
THURSDAY. KEPT A MENTION OF SLIGHT CHANCE POPS FOR THURSDAY...MAINLY
ACROSS THE WESTERN HALF OF THE FORECAST AREA.
THE ECMWF IS THE MOST PROGRESSIVE WITH THE NAM BEING A BIT SLOWER
AND THE GFS BEING THE SLOWEST OF ALL GUIDANCE. DISCOUNTED THE GFS
SOLUTION AT THIS TIME GIVEN ITS LARGE CHANGE FROM PREVIOUS RUNS
AND AS IT IS AN OUTLIER AMONG ALL GUIDANCE AND LEANING TOWARDS THE
NAM TIMING. KEPT INCREASING POPS THURSDAY NIGHT WITH CATEGORICAL
POPS EARLY FRIDAY...AND DIMINISHING POPS ON FRIDAY AFTERNOON.
THUNDER IS POSSIBLE GIVEN MARGINAL INSTABILITY.
TEMPERATURES ON THURSDAY WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE
70S AND OVERNIGHT LOWS IN THE UPPER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED FORECAST FEATURES DRY WEATHER WITH NEAR TO SLIGHTLY
BELOW NORMAL TEMPERATURES OVER THE WEEKEND...FOLLOWED BY A WEAK
WARMING TREND ON TUESDAY.
ANOTHER UPPER TROUGH AND ACCOMPANYING SURFACE COLD FRONT WILL PUSH
THROUGH THE OH/TN VALLEYS ON SATURDAY AND SHIFT OFF THE COAST BY
SUNDAY. THERE WILL BE LITTLE MOISTURE AVAILABLE FOR THE QUICK
MOVING TROUGH TO WORK WITH AS PRECIPITABLE WATER VALUES WILL BE
AROUND A HALF INCH SATURDAY AND FALL BELOW A QUARTER INCH ON SUNDAY.
A QUICK REINFORCING SHOT OF COLD AIR WILL ARRIVE FOR SUNDAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE AS THE UPPER TROUGH AXIS PASSES
OVERHEAD.
TEMPERATURES ON SATURDAY WILL RANGE FROM THE UPPER 50S NORTHERN
MIDLANDS TO LOWER 60S IN THE EASTERN MIDLANDS AND CSRA. SATURDAY
NIGHT UNDER COLD ADVECTION OVERNIGHT LOWS WILL FALL INTO THE LOWER
AND MID 30S AS HIGH PRESSURE BUILDS INTO THE REGION. SUNDAY LOOKS
TO BE THE COLDEST DAY DESPITE PLENTY OF SUNSHINE WITH HIGHS SLIGHTLY
BELOW NORMAL IN THE 50S AND A COLD NIGHT IS EXPECTED SUNDAY NIGHT
WITH HIGH PRESSURE CENTERED OVER THE FORECAST AREA. SUNDAY NIGHT
LOWS SHOULD FALL INTO THE 20S.
EARLY NEXT WEEK THE MID LEVEL FLOW BECOMES MORE ZONAL AND A
DAMPENING TROUGH MOVING THROUGH THE FLOW WILL PASS OVER THE AREA ON
TUESDAY. WILL KEEP A DRY FORECAST AT THIS TIME GIVEN UNCERTAINTY ON
DAY 7...BUT TEMPERATURES WILL REBOUND AND WARM AS SOUTHERLY FLOW
RETURNS.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
PATCHY DENSE FOG HAS DEVELOPED OVER AUGUSTA BUSH FIELD AND AT
ORANGEBURG AIRPORTS THIS MORNING. DURATION OF FOG IS SHORT WITH
VISIBILITY IMPROVING AS FAST AS IT DETERIORATES. THIS IS DUE
PRIMARILY TO LOCAL EFFECT...EXCEPT PATCHES OF FOG OVER NORTHEAST
AND EAST CENTRAL SOUTH CAROLINA ARE INFLUENCING THE VISIBILITY AT
ORANGEBURG. ADDED TEMPO IFR VISIBILITY AT BOTH LOCATIONS. OTHER
TERMINALS SHOULD REMAIN FREE OF FOG THIS MORNING.
VFR CONDITIONS WILL RETURN ACROSS ALL LOCATIONS LATER THIS
MORNING AND REMAIN FOR THE REST OF WEDNESDAY. HOWEVER APPROACHING
STORM SYSTEM WILL SPREAD CLOUDS ACROSS THE REGION LATER THIS
AFTERNOON...WITH CEILINGS LOWERING INTO 6Z THURSDAY. VISIBILITY
WILL ALSO BE AFFECTED AS WELL. THIS IS INDICATED IN THE TERMINAL
FORECASTS...WITH MVFR VISIBILITY POSSIBLE BY 6Z AT ALL LOCATIONS.
EXTENDED AVIATION OUTLOOK...IFR CONDITIONS MAY OCCUR EARLY THURSDAY
MORNING THROUGH FRIDAY MORNING AS THE STORM SYSTEM MOVES ACROSS
THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR SCZ015-016.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1052 PM EST THU JAN 26 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
PRECIPITATION WILL COME TO AN END TONIGHT AS LOW PRESSURE AND A
FRONTAL BOUNDARY MOVE EAST AWAY FROM THE OHIO VALLEY. AFTER A DRY
DAY FRIDAY...A QUICK MOVING ALBERTA CLIPPER WILL TRACK THROUGH THE
LOWER GREAT LAKES FRIDAY NIGHT WITH THE CHANCE FOR LIGHT SNOW FOR
CENTRAL INDIANA. AN ADDITIONAL CLIPPER MAY BRING FLURRIES OR LIGHT
SNOW AGAIN FOR SUNDAY MORNING. DRY WEATHER RETURNS TO END THE
WEEKEND AS HIGH PRESSURE SPREADS ACROSS THE AREA. TEMPERATURES WILL
WARM FOR EARLY NEXT WEEK WITH THE NEXT CHANCE FOR RAIN COMING
TUESDAY AND WEDNESDAY AS A FRONT MOVES THROUGH THE OHIO VALLEY.
&&
.NEAR TERM /REST OF TONIGHT/...
MAIN ADJUSTMENTS OVERNIGHT WILL BE TO SLOW DOWN ENDING OF
PRECIPITATION A LITTLE...DOWN PLAY SNOW AND ADD PATCHY FOG TO MOST
AREAS BASED ON CURRENT CONDITIONS UPSTREAM. RADAR AT 0230Z STILL
SHOWS AN EXTENSIVE AREA OF LIGHT RAIN SHOWERS ACROSS MOST OF OUR
FORECAST AREA AND RUC STILL SHOWS ACCUMULATIONS OVER MOST OF OUR
AREA THROUGH 09Z AND ACROSS THE EAST HALF THROUGH 12Z.
SO FAR NO AREAS OF SNOW HAVE DEVELOPED YET UPSTREAM AND RUC AND 18Z
GFS HAVE BACKED OFF CONSIDERABLY ON SNOWFALL LATE TONIGHT. 1000-850
MB THICKNESSES DROP BELOW 1300 METERS ALL BUT FAR SOUTHEAST BY 12Z.
BUT MOST OF THIS HAPPENS BETWEEN 09Z-12Z. WITH TEMPERATURES AND LOW
LEVEL THICKNESS MORE IFFY WILL MENTION A MIXTURE ALL BUT FAR SOUTH
AND SOUTHEAST LATE TONIGHT.
THERE HAVE BEEN AREAS OF FOG ACROSS CENTRAL ILLINOIS AND WILL ADD
MENTION OF PATCHY FOG MOST AREAS LATER TONIGHT. BUT WITH WINDS
INCREASING OVERNIGHT...I DO NOT EXPECT FOG TO BE A SIGNIFICANT
CONCERN.
AS FAR AS TEMPERATURES ARE CONCERNED...WILL RAISE LOWS A LITTLE MOST
AREAS OVERNIGHT DUE TO CLOUDS AND MILD TEMPERATURES UPSTREAM.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
SLOWED DOWN CLEARING A LITTLE ON FRIDAY AS SATELLITE SHOWS CLOUDS
EXTENDING BACK INTO EASTERN IOWA. OTHERWISE NO OTHER CHANGES MADE TO
GRIDS AFTER TONIGHT. PREVIOUS SHORT TERM DISCUSSION FOLLOWS...
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR ANOTHER QUICK SHOT OF
LIGHT SNOW FRIDAY NIGHT/EARLY SATURDAY AS A CLIPPER SYSTEM SWINGS
THROUGH THE LOWER GREAT LAKES.
FIRST CHALLENGE FOR FRIDAY FOCUSES ON THE CLOUD COVER WHICH APPEARS
INCREASINGLY LIKELY TO LINGER WELL INTO THE MORNING...ESPECIALLY
OVER THE EASTERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS SHOWING
A LEFTOVER INVERSION PRESENT WITH MOISTURE TRAPPED BENEATH IT. HAVE
THEREFORE BUMPED UP CLOUD COVER THROUGH MIDDAY...WITH DIMINISHING
LOW CLOUDS THEREAFTER AS THE INVERSION RELAXES. SUNSHINE THOUGH MAY
BE BRIEF AS MID AND HIGH LEVEL CLOUDS AHEAD OF THE APPROACHING
CLIPPER WILL ALREADY BE SPREADING INTO THE REGION FROM THE WEST BY
THE AFTERNOON THICKENING UP BY EARLY EVENING.
MODEL GUIDANCE HAS COME IN WITH A SHARPER CLIPPER SYSTEM FOR FRIDAY
NIGHT AND ALTHOUGH THE BULK OF THE DEEPER FORCING WILL REMAIN
CONFINED TO THE NORTH OF THE REGION CLOSER TO THE TRACK OF THE
LOW...SYSTEM WILL HAVE A GREATER IMPACT ON CENTRAL INDIANA AND
PARTICULARLY OVER THE NORTHERN HALF OF THE FORECAST AREA LATE FRIDAY
NIGHT. SYSTEM APPEARS TO BE A BIT STRONGER THAN PREVIOUS RUNS
INDICATED AND THERE IS MORE AMPLE MOISTURE AVAILABLE AS MID LEVEL
ENERGY DIVES OUT OF THE NORTHERN PLAINS AND HELPS AMPLIFY THE
SHORTWAVE ALOFT. DIV Q VALUES ALSO APPEAR QUITE FAVORABLE FOR A
SEVERAL HOUR PERIOD OF LIGHT TO OCCASIONALLY MODERATE SNOWFALL TO
ENCOMPASS THE NORTHERN HALF OF THE FORECAST AREA AS THE CLIPPER
PASSES THROUGH THE LOWER GREAT LAKES.
OTHER THAN A FEW FLURRIES...ANTICIPATE MUCH OF THE FORECAST AREA
REMAINS DRY UNTIL LATE EVENING AS LOWER LEVELS MOISTEN UP AND
SATURATE. AREA OF SNOW WILL THEN PROGRESS ACROSS THE FORECAST AREA
FOR THE REST OF THE NIGHT THROUGH A BOUT 12Z SATURDAY. TEMPS WILL
REMAIN NEAR IF NOT JUST ABOVE FREEZING FRIDAY EVENING AND INTO THE
OVERNIGHT BEFORE FALLING BACK INTO THE UPPER 20S/LOWER 30S WITH THE
ONSET OF SNOWFALL. GROWING CONFIDENCE IN LIGHT ACCUMULATIONS FOR
LOCATIONS NORTH OF A TERRE HAUTE-BLOOMINGTON-RUSHVILLE LINE RANGING
FROM A FEW TENTHS NEAR THOSE CITIES TO AROUND AN INCH ALONG THE I-70
CORRIDOR AND INCLUDING THE INDY METRO. OVER NORTHERN FORECAST AREA
WHERE FORCING ALOFT IS MORE ABUNDANT...FEEL 1.5 TO 2 INCHES MAY BE
ACHIEVABLE BY SATURDAY MORNING. OVER FAR SOUTHERN COUNTIES...LOWER
CONFIDENCE IN ANY SNOW ACCUMULATIONS AS BOUNDARY LAYER CONDITIONS
WILL BE MARGINAL TO SUPPORT AT BEST AND MAY SEE RA/SN MIX FOR THE
DURATION OF THE EVENT. WILL BE ISSUING AN SPS TO FURTHER HIGHLIGHT
SNOW POTENTIAL WITH THIS SYSTEM.
MUCH DRIER AIR AND A SHOT OF SUBSIDENCE ALOFT WILL SERVE TO DRY OUT
THE REGION QUICKLY SATURDAY MORNING...SETTING THE STAGE FOR A BREEZY
CHILLY DAY. STRONG HIGH PRESSURE WILL DRIFT BY TO THE SOUTH OF THE
REGION THROUGH THE COURSE OF THE DAY AND EVENING...WITH CLOUDS ONCE
AGAIN INCREASING LATE SATURDAY NIGHT AS ANOTHER CLIPPER MOVES INTO
THE WESTERN GREAT LAKES. WITH MODEL SOUNDINGS INDICATING AN
ABUNDANCE OF DRY AIR IN THE LOWER LEVELS SATURDAY NIGHT...ONLY
ANTICIPATING A FEW FLURRIES NORTH OF I-70 AT THIS TIME PRIOR TO
DAYBREAK SUNDAY.
TEMPS...WITH THE ANTICIPATED LATER DEPARTURE OF THE LOW CLOUDS
FRIDAY...LOWERED HIGHS BY A FEW DEGREES FROM PREVIOUS FORECAST. WENT
ABOVE GUIDANCE FOR LOWS FRIDAY NIGHT...THEN UNDERCUT BY SEVERAL
DEGREES SATURDAY AS COLD ADVECTION WILL KEEP TEMPS FROM RISING
MORE THAN 5 TO 8 DEGREES FROM MORNING LOWS. NEAR GUIDANCE ON LOWS
SATURDAY NIGHT FALLING INTO THE LOWER AND MID 20S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MAIN FORECAST CONCERNS WILL BE SNOWFALL CHANCES ASSOCIATED WITH
CLIPPER SYSTEM DURING THE DAY ON SUNDAY AND PRECIP WITH DEVELOPING
LOW PRESSURE SYSTEM TUESDAY AFTERNOON INTO WEDNESDAY. WITH THE FIRST
SYSTEM... THE GFS IS MORE PROGRESSIVE THAN THE ECMWF IN BRINGING THE
CLIPPER SYSTEM AND ASSOCIATED PRECIP CHANCES INTO THE NORTHEASTERN
PART OF THE FORECAST AREA. BOTH MODELS...HOWEVER...HAVE A HUNDREDTH
OR TWO OF QPF BETWEEN THE 12Z SUNDAY AND 00Z MONDAY WINDOW SO BLEND
OF GUIDANCE LOOKS REASONABLE. COLUMN TEMPS LOOK TO SUPPORT SNOW AS
THE PRECIP TYPE. WHILE PROGGED POSITIVE VORTICITY ADVECTION AND
UPPER LEVEL JET DYNAMICS FAVOR LIFT ACROSS THE NORTHEASTERN PORTION
OF THE AREA... THE SPEED OF THE SYSTEM AND LIMITED MOISTURE WILL
LIKELY KEEP SNOW TOTALS DOWN TO ONLY A TENTH OF AN INCH OR SO IN THE
NORTHEAST.
TEMPS SHOULD BOUNCE BACK TO ABOVE NORMAL STARTING MONDAY AS ZONAL
FLOW ALOFT AND SOUTHERLY SURFACE FLOW IMPACT THE AREA. CONDITIONS
SHOULD REMAIN DRY AND PARTLY CLOUDY UNTIL TUESDAY... WHEN A
DEVELOPING LOW PRESSURE SYSTEM ACROSS THE CENTRAL PLAINS LOOKS TO
APPROACH THE AREA FROM THE WEST. THE CENTER OF THE LOW IS CURRENTLY
PROGGED TO PASS NORTH OF THE AREA... PLACING THE AREA WITHIN THE
WARM SECTOR FROM NEAR 12Z TUESDAY UNTIL THE ASSOCIATED COLD FRONT
EXITS THE AREA BY 00Z THURSDAY. THE 295K ISENTROPIC ANALYSIS
SUPPORTS RAINFALL CHANCES AHEAD OF THE COLD FRONT... SO WILL KEEP
CHANCE OF RAIN THRU THE AFOREMENTIONED PERIOD. WILL LEAVE THURSDAY
DRY WITH SUBSIDENCE BEHIND THE DEPARTING SYSTEM.
&&
.AVIATION /DISCUSSION FOR 270600Z KIND TAF ISSUANCE/...
IFR CEILINGS AT THE SITES WITH SOME RAIN STILL LINGERING OVER KBMG
AND KIND THAT WILL MOVE OUT BY 8Z IF NOT BEFORE. AT KHUF AND KLAF
PRECIPITATION SHOULD BE EAST OF THE SITES BY ISSUANCE TIME WITH THE
POSSIBLE EXCEPTION OF SOME DRIZZLE AT KHUF. WHILE GUIDANCE DOESN/T
INDICATE THIS...UPSTREAM OBS SHOW THAT VISIBILITIES COULD DROP ONCE
THE PRECIPITATION MOVES OUT. WILL PROBABLY KEEP THEM AT IFR LEVELS
UNTIL DAYBREAK. CEILINGS WILL STAY IFR OR DROP TO LIFR THROUGH THE
NIGHT. SHORTLY AFTER DAYBREAK THEY SHOULD RAISE TO MVFR AND THEN VFR
AT KLAF AND KHUF. KBMG AND KIND WILL LINGER IN THE LOW CLOUDS UNTIL
MIDDAY WITH THE INVERSION TAKING LONGER TO MIX OUT THERE. AFTER 18Z
THE SITES SHOULD BE VFR. IN THE EVENING A CLIPPER SYSTEM WILL
APPROACH THAT SHOULD BRING SNOW IN NEAR THE END OF THE PERIOD. THE
SOUTHWARD EXTENT OF THIS IS FAIRLY UNCERTAIN SO WILL LEAVE OUT OF
KBMG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN/JH
LONG TERM....AB/RYAN
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
945 PM EST THU JAN 26 2012
.UPDATE...
NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
PRECIPITATION WILL COME TO AN END TONIGHT AS LOW PRESSURE AND A
FRONTAL BOUNDARY MOVE EAST AWAY FROM THE OHIO VALLEY. AFTER A DRY
DAY FRIDAY...A QUICK MOVING ALBERTA CLIPPER WILL TRACK THROUGH THE
LOWER GREAT LAKES FRIDAY NIGHT WITH THE CHANCE FOR LIGHT SNOW FOR
CENTRAL INDIANA. AN ADDITIONAL CLIPPER MAY BRING FLURRIES OR LIGHT
SNOW AGAIN FOR SUNDAY MORNING. DRY WEATHER RETURNS TO END THE
WEEKEND AS HIGH PRESSURE SPREADS ACROSS THE AREA. TEMPERATURES WILL
WARM FOR EARLY NEXT WEEK WITH THE NEXT CHANCE FOR RAIN COMING
TUESDAY AND WEDNESDAY AS A FRONT MOVES THROUGH THE OHIO VALLEY.
&&
.NEAR TERM /REST OF TONIGHT/...
MAIN ADJUSTMENTS OVERNIGHT WILL BE TO SLOW DOWN ENDING OF
PRECIPITATION A LITTLE...DOWN PLAY SNOW AND ADD PATCHY FOG TO MOST
AREAS BASED ON CURRENT CONDITIONS UPSTREAM. RADAR AT 0230Z STILL
SHOWS AN EXTENSIVE AREA OF LIGHT RAIN SHOWERS ACROSS MOST OF OUR
FORECAST AREA AND RUC STILL SHOWS ACCUMULATIONS OVER MOST OF OUR
AREA THROUGH 09Z AND ACROSS THE EAST HALF THROUGH 12Z.
SO FAR NO AREAS OF SNOW HAVE DEVELOPED YET UPSTREAM AND RUC AND 18Z
GFS HAVE BACKED OFF CONSIDERABLY ON SNOWFALL LATE TONIGHT. 1000-850
MB THICKNESSES DROP BELOW 1300 METERS ALL BUT FAR SOUTHEAST BY 12Z.
BUT MOST OF THIS HAPPENS BETWEEN 09Z-12Z. WITH TEMPERATURES AND LOW
LEVEL THICKNESS MORE IFFY WILL MENTION A MIXTURE ALL BUT FAR SOUTH
AND SOUTHEAST LATE TONIGHT.
THERE HAVE BEEN AREAS OF FOG ACROSS CENTRAL ILLINOIS AND WILL ADD
MENTION OF PATCHY FOG MOST AREAS LATER TONIGHT. BUT WITH WINDS
INCREASING OVERNIGHT...I DO NOT EXPECT FOG TO BE A SIGNIFICANT
CONCERN.
AS FAR AS TEMPERATURES ARE CONCERNED...WILL RAISE LOWS A LITTLE MOST
AREAS OVERNIGHT DUE TO CLOUDS AND MILD TEMPERATURES UPSTREAM.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
SLOWED DOWN CLEARING A LITTLE ON FRIDAY AS SATELLITE SHOWS CLOUDS
EXTENDING BACK INTO EASTERN IOWA. OTHERWISE NO OTHER CHANGES MADE TO
GRIDS AFTER TONIGHT. PREVIOUS SHORT TERM DISCUSSION FOLLOWS...
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR ANOTHER QUICK SHOT OF
LIGHT SNOW FRIDAY NIGHT/EARLY SATURDAY AS A CLIPPER SYSTEM SWINGS
THROUGH THE LOWER GREAT LAKES.
FIRST CHALLENGE FOR FRIDAY FOCUSES ON THE CLOUD COVER WHICH APPEARS
INCREASINGLY LIKELY TO LINGER WELL INTO THE MORNING...ESPECIALLY
OVER THE EASTERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS SHOWING
A LEFTOVER INVERSION PRESENT WITH MOISTURE TRAPPED BENEATH IT. HAVE
THEREFORE BUMPED UP CLOUD COVER THROUGH MIDDAY...WITH DIMINISHING
LOW CLOUDS THEREAFTER AS THE INVERSION RELAXES. SUNSHINE THOUGH MAY
BE BRIEF AS MID AND HIGH LEVEL CLOUDS AHEAD OF THE APPROACHING
CLIPPER WILL ALREADY BE SPREADING INTO THE REGION FROM THE WEST BY
THE AFTERNOON THICKENING UP BY EARLY EVENING.
MODEL GUIDANCE HAS COME IN WITH A SHARPER CLIPPER SYSTEM FOR FRIDAY
NIGHT AND ALTHOUGH THE BULK OF THE DEEPER FORCING WILL REMAIN
CONFINED TO THE NORTH OF THE REGION CLOSER TO THE TRACK OF THE
LOW...SYSTEM WILL HAVE A GREATER IMPACT ON CENTRAL INDIANA AND
PARTICULARLY OVER THE NORTHERN HALF OF THE FORECAST AREA LATE FRIDAY
NIGHT. SYSTEM APPEARS TO BE A BIT STRONGER THAN PREVIOUS RUNS
INDICATED AND THERE IS MORE AMPLE MOISTURE AVAILABLE AS MID LEVEL
ENERGY DIVES OUT OF THE NORTHERN PLAINS AND HELPS AMPLIFY THE
SHORTWAVE ALOFT. DIV Q VALUES ALSO APPEAR QUITE FAVORABLE FOR A
SEVERAL HOUR PERIOD OF LIGHT TO OCCASIONALLY MODERATE SNOWFALL TO
ENCOMPASS THE NORTHERN HALF OF THE FORECAST AREA AS THE CLIPPER
PASSES THROUGH THE LOWER GREAT LAKES.
OTHER THAN A FEW FLURRIES...ANTICIPATE MUCH OF THE FORECAST AREA
REMAINS DRY UNTIL LATE EVENING AS LOWER LEVELS MOISTEN UP AND
SATURATE. AREA OF SNOW WILL THEN PROGRESS ACROSS THE FORECAST AREA
FOR THE REST OF THE NIGHT THROUGH A BOUT 12Z SATURDAY. TEMPS WILL
REMAIN NEAR IF NOT JUST ABOVE FREEZING FRIDAY EVENING AND INTO THE
OVERNIGHT BEFORE FALLING BACK INTO THE UPPER 20S/LOWER 30S WITH THE
ONSET OF SNOWFALL. GROWING CONFIDENCE IN LIGHT ACCUMULATIONS FOR
LOCATIONS NORTH OF A TERRE HAUTE-BLOOMINGTON-RUSHVILLE LINE RANGING
FROM A FEW TENTHS NEAR THOSE CITIES TO AROUND AN INCH ALONG THE I-70
CORRIDOR AND INCLUDING THE INDY METRO. OVER NORTHERN FORECAST AREA
WHERE FORCING ALOFT IS MORE ABUNDANT...FEEL 1.5 TO 2 INCHES MAY BE
ACHIEVABLE BY SATURDAY MORNING. OVER FAR SOUTHERN COUNTIES...LOWER
CONFIDENCE IN ANY SNOW ACCUMULATIONS AS BOUNDARY LAYER CONDITIONS
WILL BE MARGINAL TO SUPPORT AT BEST AND MAY SEE RA/SN MIX FOR THE
DURATION OF THE EVENT. WILL BE ISSUING AN SPS TO FURTHER HIGHLIGHT
SNOW POTENTIAL WITH THIS SYSTEM.
MUCH DRIER AIR AND A SHOT OF SUBSIDENCE ALOFT WILL SERVE TO DRY OUT
THE REGION QUICKLY SATURDAY MORNING...SETTING THE STAGE FOR A BREEZY
CHILLY DAY. STRONG HIGH PRESSURE WILL DRIFT BY TO THE SOUTH OF THE
REGION THROUGH THE COURSE OF THE DAY AND EVENING...WITH CLOUDS ONCE
AGAIN INCREASING LATE SATURDAY NIGHT AS ANOTHER CLIPPER MOVES INTO
THE WESTERN GREAT LAKES. WITH MODEL SOUNDINGS INDICATING AN
ABUNDANCE OF DRY AIR IN THE LOWER LEVELS SATURDAY NIGHT...ONLY
ANTICIPATING A FEW FLURRIES NORTH OF I-70 AT THIS TIME PRIOR TO
DAYBREAK SUNDAY.
TEMPS...WITH THE ANTICIPATED LATER DEPARTURE OF THE LOW CLOUDS
FRIDAY...LOWERED HIGHS BY A FEW DEGREES FROM PREVIOUS FORECAST. WENT
ABOVE GUIDANCE FOR LOWS FRIDAY NIGHT...THEN UNDERCUT BY SEVERAL
DEGREES SATURDAY AS COLD ADVECTION WILL KEEP TEMPS FROM RISING
MORE THAN 5 TO 8 DEGREES FROM MORNING LOWS. NEAR GUIDANCE ON LOWS
SATURDAY NIGHT FALLING INTO THE LOWER AND MID 20S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MAIN FORECAST CONCERNS WILL BE SNOWFALL CHANCES ASSOCIATED WITH
CLIPPER SYSTEM DURING THE DAY ON SUNDAY AND PRECIP WITH DEVELOPING
LOW PRESSURE SYSTEM TUESDAY AFTERNOON INTO WEDNESDAY. WITH THE FIRST
SYSTEM... THE GFS IS MORE PROGRESSIVE THAN THE ECMWF IN BRINGING THE
CLIPPER SYSTEM AND ASSOCIATED PRECIP CHANCES INTO THE NORTHEASTERN
PART OF THE FORECAST AREA. BOTH MODELS...HOWEVER...HAVE A HUNDREDTH
OR TWO OF QPF BETWEEN THE 12Z SUNDAY AND 00Z MONDAY WINDOW SO BLEND
OF GUIDANCE LOOKS REASONABLE. COLUMN TEMPS LOOK TO SUPPORT SNOW AS
THE PRECIP TYPE. WHILE PROGGED POSITIVE VORTICITY ADVECTION AND
UPPER LEVEL JET DYNAMICS FAVOR LIFT ACROSS THE NORTHEASTERN PORTION
OF THE AREA... THE SPEED OF THE SYSTEM AND LIMITED MOISTURE WILL
LIKELY KEEP SNOW TOTALS DOWN TO ONLY A TENTH OF AN INCH OR SO IN THE
NORTHEAST.
TEMPS SHOULD BOUNCE BACK TO ABOVE NORMAL STARTING MONDAY AS ZONAL
FLOW ALOFT AND SOUTHERLY SURFACE FLOW IMPACT THE AREA. CONDITIONS
SHOULD REMAIN DRY AND PARTLY CLOUDY UNTIL TUESDAY... WHEN A
DEVELOPING LOW PRESSURE SYSTEM ACROSS THE CENTRAL PLAINS LOOKS TO
APPROACH THE AREA FROM THE WEST. THE CENTER OF THE LOW IS CURRENTLY
PROGGED TO PASS NORTH OF THE AREA... PLACING THE AREA WITHIN THE
WARM SECTOR FROM NEAR 12Z TUESDAY UNTIL THE ASSOCIATED COLD FRONT
EXITS THE AREA BY 00Z THURSDAY. THE 295K ISENTROPIC ANALYSIS
SUPPORTS RAINFALL CHANCES AHEAD OF THE COLD FRONT... SO WILL KEEP
CHANCE OF RAIN THRU THE AFOREMENTIONED PERIOD. WILL LEAVE THURSDAY
DRY WITH SUBSIDENCE BEHIND THE DEPARTING SYSTEM.
&&
.AVIATION /DISCUSSION FOR 270300Z KIND TAF ISSUANCE/...
ONLY CHANGE WAS TO TWEAK CURRENT CONDITIONS. PREVIOUS DISCUSSION
FOLLOWS...
IFR/LIFR CEILINGS CONTINUE ACROSS THE SITES AND NO IMPROVEMENT
EXPECTED UNTIL AT LEAST 12Z. ANOTHER SURFACE WAVE IS BRINGING RAIN
BACK INTO THE SITES. SURFACE TEMPERATURES ARE EXPECTED TO REMAIN
ABOVE FREEZING UNTIL AFTER THE PRECIPITATION HAS MOVED OUT OF THE
AREA. RAIN WILL BE THE PREDOMINANT PRECIP TYPE THROUGH 3Z AT ALL THE
SITES. BETWEEN 3 AND 6Z A CHANGEOVER TO A RAIN/SNOW MIX IS POSSIBLE
FIRST AT KLAF AND THEN AT KIND. FORECAST SOUNDINGS FOR KHUF LOOK
MORE LIKE RAIN WILL STOP THERE AROUND 4-6Z AND DRIZZLE MAY TAKE ITS
PLACE FOR A FEW HOURS BEFORE PRECIP ENDS. PRECIPITATION SHOULD BE
CLEAR OF ALL SITES BY 10Z OR SO AS THE SURFACE WAVE MOVES NORTHEAST
AWAY FROM THE AREA. CEILINGS SHOULD BEGIN TO IMPROVE AT KLAF AND
KHUF AROUND 12Z...BUT LOW CEILINGS MAY LINGER LONGER AT KBMG AND
KIND WITH A STRONGER INVERSION THERE THAT DOESN/T MIX OUT UNTIL
16-18Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN/JH
LONG TERM....AB/RYAN
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
330 PM EST WED JAN 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST ALONG A WARM FRONT INTO THE
OHIO VALLEY TONIGHT. A STRONGER UPPER LOW WILL THEN PASS THROUGH
THE TENNESSEE VALLEY ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW
PRESSURE ALOFT. AS THIS UPPER SYSTEM DEPARTS ON THURSDAY
NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF INDIANA WILL
PUSH EAST AS A COLD FRONT. AFTERWARD DRY...NORTHWEST FLOW OF
CANADIAN AIR WILL BEGIN ACROSS CENTRAL INDIANA. HIGH PRESSURE WILL
RETURN TO THE STATE ON FRIDAY BRINGING DRY WEATHER BACK TO THE
STATE FOR THE WEEKEND AND INTO EARLY NEXT WEEK. THE NEXT SYSTEM TO
IMPACT THE REGION WILL ARRIVE NEXT TUESDAY INTO TUESDAY NIGHT.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SURFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BY THE START OF THE EXTENDED PERIOD ENSEMBLES HAVE THE REGION
ESTABLISHED IN ZONAL FLOW WHICH LASTS THROUGH EARLY NEXT WEEK. A
WEAK UPPER TROUGH SHIFTS THROUGH THE GREAT LAKES REGION SUNDAY INTO
SUNDAY NIGHT BUT THIS FEATURE APPEARS TO STAY FAR NORTHWARD SO AS
NOT TO AFFECT CENTRAL INDIANA. THE FORECAST AREA WILL THEREFORE
REMAIN DRY FOR THE MAJORITY OF THE PERIOD...AND TEMPERATURES WILL
MODERATE BACK TO ABOVE NORMAL BY EARLY NEXT WEEK. ENSEMBLES SUGGEST
THE NEXT UPPER SYSTEM WILL NOT ARRIVE UNTIL TUESDAY INTO TUESDAY
NIGHT...WHICH THEY HAVE BEEN DEPICTING THESE PAST FEW MODEL RUNS.
BUMPED UP CHANCE POPS SLIGHTLY DURING THIS PERIOD TO ACCOUNT FOR
GOOD CONTINUITY AND CONSENSUS THUS FAR. PRECIPITATION TYPE AT THIS
TIME LOOKS TO BE ALL RAIN.
&&
.AVIATION /DISCUSSION FOR THE 252100Z TAFS/...
1945Z UPDATE...ADDED SLEET TO KIND TAF BASED ON REPORTS UPSTREAM.
THIS IS A VERY TRICKY FORECAST SO OPTED TO USE -RAPL FOR NOW UNTIL
03Z. THIS SHOULD NOT HAVE AN IMMEDIATE IMPACT UPON FLIGHT
CATEGORY...HOWEVER THAT SHOULD CHANGE IN A COUPLE OF HOURS.
PREVIOUS DISCUSSION FOLLOWS...
1900Z UPDATE...ADDED -RASN TO KHUF TAF BASED ON OBSERVATIONS
UPSTREAM. THIS SHOULD NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AT
THIS TIME BUT WILL CONTINUE TO MONITOR FOR FUTURE UPDATES.
PREVIOUS DISCUSSION FOLLOWS...
VERY TRICKY PUBLIC AND AVIATION FORECAST SHAPING UP FOR THE REST
OF TODAY AND TONIGHT. AS TEMPERATURES HOVER AROUND THE FREEZING
MARK THIS HOUR...RAIN IS TRYING TO SPREAD INTO CENTRAL INDIANA
FROM THE SW. AS EXPECTED...CEILINGS ARE GRADUALLY LOWERING AND
WILL CONTINUE THIS TREND UNTIL THEY ARE AT MFVR THIS EVENING WITH
THE CHANCE FOR -RA. WITH SURFACE TEMPS RIGHT AROUND THE FREEZING
MARK...FREEZING RAIN AND EVEN SLEET CANNOT BE RULED OUT AT TIMES
ACROSS THE AREA. BUT FOR NOW BASED ON WARMER TEMP TRENDS (AND
MODEL THICKNESSES) OPTED TO GO WITH JUST -RA THE ENTIRE PERIOD.
DEEPER MOISTURE MOVES INTO THE AREA TONIGHT INTO THURSDAY AND A
PROLONGED PERIOD OF IFR CAN BE EXPECTED AT ALL OF THE TERMINALS
BEGINNING BETWEEN 04-08Z AND LASTING THROUGH ALL OF THU MORNING.
FLIGHT CONDITIONS ARE NOT SET TO IMPROVE AT THE END OF THE TAF
PERIOD...AT BEST ONLY TO LOW END MFVR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...SMF
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....SMF
AVIATION...SMF/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
248 PM EST WED JAN 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST ALONG A WARM FRONT INTO THE
OHIO VALLEY TONIGHT. A STRONGER UPPER LOW WILL THEN PASS THROUGH
THE TENNESSEE VALLEY ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW
PRESSURE ALOFT. AS THIS UPPER SYSTEM DEPARTS ON THURSDAY
NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF INDIANA WILL
PUSH EAST AS A COLD FRONT. AFTERWARD DRY...NORTHWEST FLOW OF
CANADIAN AIR WILL BEGIN ACROSS CENTRAL INDIANA. HIGH PRESSURE WILL
RETURN TO THE STATE ON FRIDAY BRINGING DRY WEATHER BACK TO THE
STATE FOR THE WEEKEND AND INTO EARLY NEXT WEEK. THE NEXT SYSTEM TO
IMPACT THE REGION WILL ARRIVE NEXT TUESDAY INTO TUESDAY NIGHT.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SURFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BY THE START OF THE EXTENDED PERIOD ENSEMBLES HAVE THE REGION
ESTABLISHED IN ZONAL FLOW WHICH LASTS THROUGH EARLY NEXT WEEK. A
WEAK UPPER TROUGH SHIFTS THROUGH THE GREAT LAKES REGION SUNDAY INTO
SUNDAY NIGHT BUT THIS FEATURE APPEARS TO STAY FAR NORTHWARD SO AS
NOT TO AFFECT CENTRAL INDIANA. THE FORECAST AREA WILL THEREFORE
REMAIN DRY FOR THE MAJORITY OF THE PERIOD...AND TEMPERATURES WILL
MODERATE BACK TO ABOVE NORMAL BY EARLY NEXT WEEK. ENSEMBLES SUGGEST
THE NEXT UPPER SYSTEM WILL NOT ARRIVE UNTIL TUESDAY INTO TUESDAY
NIGHT...WHICH THEY HAVE BEEN DEPICTING THESE PAST FEW MODEL RUNS.
BUMPED UP CHANCE POPS SLIGHTLY DURING THIS PERIOD TO ACCOUNT FOR
GOOD CONTINUITY AND CONSENSUS THUS FAR. PRECIPITATION TYPE AT THIS
TIME LOOKS TO BE ALL RAIN.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAFS/...
1945Z UPDATE...ADDED SLEET TO KIND TAF BASED ON REPORTS UPSTREAM.
THIS IS A VERY TRICKY FORECAST SO OPTED TO USE -RAPL FOR NOW UNTIL
03Z. THIS SHOULD NOT HAVE AN IMMEDIATE IMPACT UPON FLIGHT
CATEGORY...HOWEVER THAT SHOULD CHANGE IN A COUPLE OF HOURS.
PREVIOUS DISCUSSION FOLLOWS...
1900Z UPDATE...ADDED -RASN TO KHUF TAF BASED ON OBSERVATIONS
UPSTREAM. THIS SHOULD NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AT
THIS TIME BUT WILL CONTINUE TO MONITOR FOR FUTURE UPDATES.
PREVIOUS DISCUSSION FOLLOWS...
VERY TRICKY PUBLIC AND AVIATION FORECAST SHAPING UP FOR THE REST
OF TODAY AND TONIGHT. AS TEMPERATURES HOVER AROUND THE FREEZING
MARK THIS HOUR...RAIN IS TRYING TO SPREAD INTO CENTRAL INDIANA
FROM THE SW. AS EXPECTED...CEILINGS ARE GRADUALLY LOWERING AND
WILL CONTINUE THIS TREND UNTIL THEY ARE AT MFVR THIS EVENING WITH
THE CHANCE FOR -RA. WITH SURFACE TEMPS RIGHT AROUND THE FREEZING
MARK...FREEZING RAIN AND EVEN SLEET CANNOT BE RULED OUT AT TIMES
ACROSS THE AREA. BUT FOR NOW BASED ON WARMER TEMP TRENDS (AND
MODEL THICKNESSES) OPTED TO GO WITH JUST -RA THE ENTIRE PERIOD.
DEEPER MOISTURE MOVES INTO THE AREA TONIGHT INTO THURSDAY AND A
PROLONGED PERIOD OF IFR CAN BE EXPECTED AT ALL OF THE TERMINALS
BEGINNING BETWEEN 04-08Z AND LASTING THROUGH ALL OF THU MORNING.
FLIGHT CONDITIONS ARE NOT SET TO IMPROVE AT THE END OF THE TAF
PERIOD...AT BEST ONLY TO LOW END MFVR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...SMF
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
238 PM EST WED JAN 25 2012
.UPDATE...
THE SYNOPSIS SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST ALONG A WARM FRONT INTO THE
OHIO VALLEY TONIGHT. A STRONGER UPPER LOW WILL THEN PASS THROUGH
THE TENNESSEE VALLEY ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW
PRESSURE ALOFT. AS THIS UPPER SYSTEM DEPARTS ON THURSDAY
NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF INDIANA WILL
PUSH EAST AS A COLD FRONT. AFTERWARD DRY...NORTHWEST FLOW OF
CANADIAN AIR WILL BEGIN ACROSS CENTRAL INDIANA. HIGH PRESSURE WILL
RETURN TO THE STATE ON FRIDAY BRINGING DRY WEATHER BACK TO THE
STATE FOR THE WEEKEND AND INTO EARLY NEXT WEEK. THE NEXT SYSTEM TO
IMPACT THE REGION WILL ARRIVE NEXT TUESDAY INTO TUESDAY NIGHT.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SURFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BY THE START OF THE EXTENDED PERIOD ENSEMBLES HAVE THE REGION
ESTABLISHED IN ZONAL FLOW WHICH LASTS THROUGH EARLY NEXT WEEK. A
WEAK UPPER TROUGH SHIFTS THROUGH THE GREAT LAKES REGION SUNDAY INTO
SUNDAY NIGHT BUT THIS FEATURE APPEARS TO STAY FAR NORTHWARD SO AS
NOT TO AFFECT CENTRAL INDIANA. THE FORECAST AREA WILL THEREFORE
REMAIN DRY FOR THE MAJORITY OF THE PERIOD...AND TEMPERATURES WILL
MODERATE BACK TO ABOVE NORMAL BY EARLY NEXT WEEK. ENSEMBLES SUGGEST
THE NEXT UPPER SYSTEM WILL NOT ARRIVE UNTIL TUESDAY INTO TUESDAY
NIGHT...WHICH THEY HAVE BEEN DEPICTING THESE PAST FEW MODEL RUNS.
BUMPED UP CHANCE POPS SLIGHTLY DURING THIS PERIOD TO ACCOUNT FOR
GOOD CONTINUITY AND CONSENSUS THUS FAR. PRECIPITATION TYPE AT THIS
TIME LOOKS TO BE ALL RAIN.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAFS/...
19Z UPDATE...ADDED -RASN TO KHUF TAF BASED ON OBSERVATIONS
UPSTREAM. THIS SHOULD NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AT
THIS TIME BUT WILL CONTINUE TO MONITOR FOR FUTURE UPDATES.
PREVIOUS DISCUSSION FOLLOWS...
VERY TRICKY PUBLIC AND AVIATION FORECAST SHAPING UP FOR THE REST
OF TODAY AND TONIGHT. AS TEMPERATURES HOVER AROUND THE FREEZING
MARK THIS HOUR...RAIN IS TRYING TO SPREAD INTO CENTRAL INDIANA
FROM THE SW. AS EXPECTED...CEILINGS ARE GRADUALLY LOWERING AND
WILL CONTINUE THIS TREND UNTIL THEY ARE AT MFVR THIS EVENING WITH
THE CHANCE FOR -RA. WITH SURFACE TEMPS RIGHT AROUND THE FREEZING
MARK...FREEZING RAIN AND EVEN SLEET CANNOT BE RULED OUT AT TIMES
ACROSS THE AREA. BUT FOR NOW BASED ON WARMER TEMP TRENDS (AND
MODEL THICKNESSES) OPTED TO GO WITH JUST -RA THE ENTIRE PERIOD.
DEEPER MOISTURE MOVES INTO THE AREA TONIGHT INTO THURSDAY AND A
PROLONGED PERIOD OF IFR CAN BE EXPECTED AT ALL OF THE TERMINALS
BEGINNING BETWEEN 04-08Z AND LASTING THROUGH ALL OF THU MORNING.
FLIGHT CONDITIONS ARE NOT SET TO IMPROVE AT THE END OF THE TAF
PERIOD...AT BEST ONLY TO LOW END MFVR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...SMF
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
214 PM EST WED JAN 25 2012
.UPDATE...
THE LONG TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WAS FOUND ACROSS CENTRAL INDIANA EARLY
THIS MORNING. THE HIGH WILL DRIFT EAST OF INDIANA TODAY AS LOW
PRESSURE DEVELOPS IN THE SOUTHERN PLAINS. THE LOW WILL TRACK
NORTHEAST ALONG A WARM FRONT INTO THE OHIO VALLEY
TONIGHT...SPREADING RAIN SHOWERS.
A STRONGER UPPER LOW WILL THEN PASS THROUGH THE TENNESSEE VALLEY
ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW PRESSURE ALOFT. THIS
WILL RESULT IN A WET THURSDAY. AS THIS UPPER SYSTEM DEPARTS ON
THURSDAY NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF
INDIANA WILL PUSH EAST AS WELL AS A COLD FRONT AND A
DRY...NORTHWEST FLOW OF CANADIAN AIR WILL BEGIN ACROSS CENTRAL
INDIANA.
HIGH PRESSURE WILL THEN RETURN TO THE STATE ON FRIDAY BRINGING DRY
WEATHER BACK TO THE STATE FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SUFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BY THE START OF THE EXTENDED PERIOD ENSEMBLES HAVE THE REGION
ESTABLISHED IN ZONAL FLOW WHICH LASTS THROUGH EARLY NEXT WEEK. A
WEAK UPPER TROUGH SHIFTS THROUGH THE GREAT LAKES REGION SUNDAY INTO
SUNDAY NIGHT BUT THIS FEATURE APPEARS TO STAY FAR NORTHWARD SO AS
NOT TO AFFECT CENTRAL INDIANA. THE FORECAST AREA WILL THEREFORE
REMAIN DRY FOR THE MAJORITY OF THE PERIOD...AND TEMPERATURES WILL
MODERATE BACK TO ABOVE NORMAL BY EARLY NEXT WEEK. ENSEMBLES SUGGEST
THE NEXT UPPER SYSTEM WILL NOT ARRIVE UNTIL TUESDAY INTO TUESDAY
NIGHT...WHICH THEY HAVE BEEN DEPICTING THESE PAST FEW MODEL RUNS.
BUMPED UP CHANCE POPS SLIGHTLY DURING THIS PERIOD TO ACCOUNT FOR
GOOD CONTINUITY AND CONSENSUS THUS FAR. PRECIPITATION TYPE AT THIS
TIME LOOKS TO BE ALL RAIN.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAFS/...
19Z UPDATE...ADDED -RASN TO KHUF TAF BASED ON OBSERVATIONS
UPSTREAM. THIS SHOULD NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AT
THIS TIME BUT WILL CONTINUE TO MONITOR FOR FUTURE UPDATES.
PREVIOUS DISCUSSION FOLLOWS...
VERY TRICKY PUBLIC AND AVIATION FORECAST SHAPING UP FOR THE REST
OF TODAY AND TONIGHT. AS TEMPERATURES HOVER AROUND THE FREEZING
MARK THIS HOUR...RAIN IS TRYING TO SPREAD INTO CENTRAL INDIANA
FROM THE SW. AS EXPECTED...CEILINGS ARE GRADUALLY LOWERING AND
WILL CONTINUE THIS TREND UNTIL THEY ARE AT MFVR THIS EVENING WITH
THE CHANCE FOR -RA. WITH SURFACE TEMPS RIGHT AROUND THE FREEZING
MARK...FREEZING RAIN AND EVEN SLEET CANNOT BE RULED OUT AT TIMES
ACROSS THE AREA. BUT FOR NOW BASED ON WARMER TEMP TRENDS (AND
MODEL THICKNESSES) OPTED TO GO WITH JUST -RA THE ENTIRE PERIOD.
DEEPER MOISTURE MOVES INTO THE AREA TONIGHT INTO THURSDAY AND A
PROLONGED PERIOD OF IFR CAN BE EXPECTED AT ALL OF THE TERMINALS
BEGINNING BETWEEN 04-08Z AND LASTING THROUGH ALL OF THU MORNING.
FLIGHT CONDITIONS ARE NOT SET TO IMPROVE AT THE END OF THE TAF
PERIOD...AT BEST ONLY TO LOW END MFVR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1233 PM EST WED JAN 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WAS FOUND ACROSS CENTRAL INDIANA EARLY
THIS MORNING. THE HIGH WILL DRIFT EAST OF INDIANA TODAY AS LOW
PRESSURE DEVELOPS IN THE SOUTHERN PLAINS. THE LOW WILL TRACK
NORTHEAST ALONG A WARM FRONT INTO THE OHIO VALLEY
TONIGHT...SPREADING RAIN SHOWERS.
A STRONGER UPPER LOW WILL THEN PASS THROUGH THE TENNESSEE VALLEY
ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW PRESSURE ALOFT. THIS
WILL RESULT IN A WET THURSDAY. AS THIS UPPER SYSTEM DEPARTS ON
THURSDAY NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF
INDIANA WILL PUSH EAST AS WELL AS A COLD FRONT AND A
DRY...NORTHWEST FLOW OF CANADIAN AIR WILL BEGIN ACROSS CENTRAL
INDIANA.
HIGH PRESSURE WILL THEN RETURN TO THE STATE ON FRIDAY BRINGING DRY
WEATHER BACK TO THE STATE FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SUFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA ARE SUGGESTING BROAD UPPER LEVEL TROUGHING OVER THE
EASTERN PARTS OF THE COUNTRY...WHICH BECOMES MORE ZONAL BY EARLY
NEXT WEEK. LOOKS LIKE A PRETTY QUIET PERIOD...WITH THE ENSEMBLES
SUGGESTING THE NEXT UPPER SYSTEM NOT ARRIVING UNTIL NEXT TUESDAY.
WILL INTRODUCE CHANCE POPS AT THAT TIME. SYSTEM LOOKS TO BE A RAIN
PRODUCER AT THIS TIME WITH ONLY A COUPLE OF MEMBERS INDICATING
SNOW POTENTIAL WITH THIS SYSTEM.
A FEW ENSEMBLES ARE BEGINNING TO INDICATE THE POTENTIAL FOR A
CLIPPER TYPE SYSTEM MOVING THROUGH THE GENERAL AREA OVER THIS
WEEKEND...WITH THE POTENTIAL FOR SOME LIGHT SNOWS. AT THIS
TIME...WILL KEEP THE WEEKEND DRY...BUT MAY NEED TO ADD POPS FOR
LIGHT SNOW AT A LATER TIME.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAFS/...
VERY TRICKY PUBLIC AND AVIATION FORECAST SHAPING UP FOR THE REST
OF TODAY AND TONIGHT. AS TEMPERATURES HOVER AROUND THE FREEZING
MARK THIS HOUR...RAIN IS TRYING TO SPREAD INTO CENTRAL INDIANA
FROM THE SW. AS EXPECTED...CEILINGS ARE GRADUALLY LOWERING AND
WILL CONTINUE THIS TREND UNTIL THEY ARE AT MFVR THIS EVENING WITH
THE CHANCE FOR -RA. WITH SURFACE TEMPS RIGHT AROUND THE FREEZING
MARK...FREEZING RAIN AND EVEN SLEET CANNOT BE RULED OUT AT TIMES
ACROSS THE AREA. BUT FOR NOW BASED ON WARMER TEMP TRENDS (AND
MODEL THICKNESSES) OPTED TO GO WITH JUST -RA THE ENTIRE PERIOD.
DEEPER MOISTURE MOVES INTO THE AREA TONIGHT INTO THURSDAY AND A
PROLONGED PERIOD OF IFR CAN BE EXPECTED AT ALL OF THE TERMINALS
BEGINNING BETWEEN 04-08Z AND LASTING THROUGH ALL OF THU MORNING.
FLIGHT CONDITIONS ARE NOT SET TO IMPROVE AT THE END OF THE TAF
PERIOD...AT BEST ONLY TO LOW END MFVR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 AM EST WED JAN 25 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WAS FOUND ACROSS CENTRAL INDIANA EARLY
THIS MORNING. THE HIGH WILL DRIFT EAST OF INDIANA TODAY AS LOW
PRESSURE DEVELOPS IN THE SOUTHERN PLAINS. THE LOW WILL TRACK
NORTHEAST ALONG A WARM FRONT INTO THE OHIO VALLEY
TONIGHT...SPREADING RAIN SHOWERS.
A STRONGER UPPER LOW WILL THEN PASS THROUGH THE TENNESSEE VALLEY
ON THURSDAY ACCOMPANIED BY A TROUGH OF LOW PRESSURE ALOFT. THIS
WILL RESULT IN A WET THURSDAY. AS THIS UPPER SYSTEM DEPARTS ON
THURSDAY NIGHT...THE FRONTAL BOUNDARY TO THE SOUTH AND EAST OF
INDIANA WILL PUSH EAST AS WELL AS A COLD FRONT AND A
DRY...NORTHWEST FLOW OF CANADIAN AIR WILL BEGIN ACROSS CENTRAL
INDIANA.
HIGH PRESSURE WILL THEN RETURN TO THE STATE ON FRIDAY BRINGING DRY
WEATHER BACK TO THE STATE FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN FORECAST CONCERN TODAY IS PRECIPITATION AND TEMPERATURE
TREND... MOREOVER WHAT PRECIP TYPES WILL IMPACT THE AREA WITH
APPROACHING SURFACE LOW TO THE SOUTHWEST. UPON A COMPARISON WITH
CURRENT OBSERVATIONS... THE NAM HAS A GOOD HANDLE ON SURFACE
FEATURES AND BOTH NAM AND RUC HAVE THE BEST HANDLE ON SURFACE TEMPS
SO FAR. SHORT RANGE ENSEMBLE GUIDANCE GOES A BIT WARM KEEPING NEARLY
ALL OF THE FORECAST AREA ABOVE FREEZING WHEN THE PRECIPITATION
OCCURS. CURRENT THINKING WEIGHS IN MORE ON THE NAM AND RUC WITH
KEEPING NEAR TO SLIGHTLY BELOW FREEZING TEMPS ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA.
THE NORTHERN MAJORITY OF THE AREA HAS BEEN TRENDING A FEW DEGREES
ABOVE PREVIOUS FORECAST... HOWEVER CONSIDERING EVAPORATIONAL COOLING
WITH ONSET OF PRECIP... THE TEMPS WILL LIKELY STAY STEADY OR ONLY
INCREASE BY A FEW DEGREES. THIS WILL KEEP THE NORTHERN HALF OF THE
FORECAST AREA AT 31 TO 33 DEGREES THRU 00Z. MAX TEMPS IN THE SOUTH
WILL LIKELY GET TO THE MID 30S.
FOR PRECIP TIMING AND AMOUNT... SHORT RANGE GUIDANCE IS IN GOOD
AGREEMENT WITH ONSET OF PRECIP OCCURRING FROM THE SOUTHWEST STARTING
NEAR 18Z AND SPREADING NORTHEASTWARD ACROSS THE MAJORITY OF THE
FORECAST AREA BY 00Z. QPF LOOKS TO BE LIGHT WITH A FEW HUNDREDTHS IN
THE NORTH TO NEAR A TENTH OF AN INCH IN THE SOUTHWEST... WHERE MORE
RAIN SHOWERS WILL HAVE OCCURRED.
CONSIDERING THE ABOVE ALONG WITH FORECAST SOUNDING DATA AND THE
DEPTH OF THE WARM NOSE IN THE SATURATED COLUMN... PRECIP MAY START
OUT AS A BRIEF PERIOD OF LIGHT SLEET OR FREEZING DRIZZLE... BUT THEN
LIKELY TRANSITION TO LIGHT RAIN SHOWERS AND DRIZZLE AS WARM
ADVECTION AHEAD OF THE APPROACHING LOW BATTLES AGAINST THE LOW LEVEL
INVERSION.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
WARM FRONT WILL BE SET UP ALONG THE OHIO RIVER TONIGHT AS PREVIOUSLY
DISCUSSED ISENTROPIC LIFT AND MOISTURE CONTINUES. UPPER SUPPORT
REMAINS QUITE FAVORABLE TONIGHT AS A SHORT WAVE IS EXPECTED TOWARD
INDIANA FROM THE MAIN LOW. FURTHERMORE IN THE LOWER LEVELS MILD
AND MOIST GULF AIR CONTINUES TO STREAM INTO THE OHIO VALLEY. RAIN IS
EXPECTED TO REMAIN ACROSS THE AREA INTO THE EVENING HOURS. TIME
HEIGHTS AND FORECAST SOUNDINGS INDICATE SATURATION INTO THE
EVENINGS HOURS AS WELL. THUS WILL AGAIN USE WETTER POPS TONIGHT.
GIVEN THE EXPECTED CLOUDS AND RAIN WILL TREND TONIGHTS LOWS
WARMER THAN MAVMOS. SOME COOLER AIR AT THE SUFACE ACROSS THE
NORTHERN PARTS OF THE FORECAST AREA...LAFAYETTE...KOKOMO...MAY
RESULT IN SOME SNOW BEING MIXED IN AT THOSE LOCATIONS. ALTHOUGH
ACCUMULATIONS WOULD BE MINIMAL TO NONE.
MORE RAIN WILL BE EXPECTED ON THURSDAY AS THE UPPER LOW OVER THE
SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE ALOFT PUSH ACROSS THE
REGION PROVIDING AMPLE LIFT. FORECAST SOUNDINGS CONTINUE TO
INDICATE DEEP SATURATION AND KEEP THE LOWEST LEVELS OF THE
ATMOSPHERE ABOVE FREEZING. AGAIN WILL TREND HIGHER THAN MAVMOS
POPS ON THURSDAY AND COOLER ON HIGH TEMPERATURES GIVEN THE
EXPECTED RAIN.
UPPER SUPPORT FINALLY EXITS THE AREA TO THE EAST ON THURSDAY
NIGHT INTO FRIDAY MORNING AS A COOLER NORTHWEST FLOW BEGINS TO
TAKE SHAPE. FORECAST SOUNDINGS SHOW SIGNIFICANT DRYING AFTER 00Z
FRIDAY AS STRONG SUBSIDENCE TAKES SHAPE. 850MB SURFACE SHOWS
STRONG COLD AIR ADVECTION ACROSS THE AREA AS THEY FALL TO THE NEAR
-2C BY 12Z FRI. FORECAST SOUNDINGS ALSO DO NOT HINT AT LINGERING
STRATOCU AS STRONG SURFACE RIDGING BUILDS ACROSS THE AREA ON
THURSDAY NIGHT. THUS WILL TREND TOWARD BECOMING CLEAR ALONG WITH
LOWS ON THURSDAY NIGHT COOLER THAN MAVMOS.
DRY WEATHER IS EXPECTED ON FRIDAY AS THE SURFACE RIDGE MOVES
ACROSS THE AREA. THE QUICK NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME
PASSING CLOUDS...BUT FOR NOW PTCLDY WILL WORK FIND ALONG WITH
TEMPS COOLER THAN MAVMOS GIVEN THE 850MB TEMPS.
A WEAK CLIPPER IS THEN EXPECTED TO PUSH THROUGH THE AREA ON FRIDAY
NIGHT. HOWEVER MOISTURE WILL REMAIN A PROBLEM WITH THIS WEAK SYSTEM
AS IT WILL ONLY HAVE PACIFIC MOISTURE TO WORK WITH AND ONLY
MARGINAL SUPPORT ALOFT. FOR NOW WILL TREND TOWARD JUST A MOSTLY
CLOUDY SKY...WITH LOWS COOLER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA ARE SUGGESTING BROAD UPPER LEVEL TROUGHING OVER THE
EASTERN PARTS OF THE COUNTRY...WHICH BECOMES MORE ZONAL BY EARLY
NEXT WEEK. LOOKS LIKE A PRETTY QUIET PERIOD...WITH THE ENSEMBLES
SUGGESTING THE NEXT UPPER SYSTEM NOT ARRIVING UNTIL NEXT TUESDAY.
WILL INTRODUCE CHANCE POPS AT THAT TIME. SYSTEM LOOKS TO BE A RAIN
PRODUCER AT THIS TIME WITH ONLY A COUPLE OF MEMBERS INDICATING
SNOW POTENTIAL WITH THIS SYSTEM.
A FEW ENSEMBLES ARE BEGINNING TO INDICATE THE POTENTIAL FOR A
CLIPPER TYPE SYSTEM MOVING THROUGH THE GENERAL AREA OVER THIS
WEEKEND...WITH THE POTENTIAL FOR SOME LIGHT SNOWS. AT THIS
TIME...WILL KEEP THE WEEKEND DRY...BUT MAY NEED TO ADD POPS FOR
LIGHT SNOW AT A LATER TIME.
&&
.AVIATION /DISCUSSION FOR THE 251200Z TAFS/...
1430Z UPDATE...MOISTURE IS MAKING IT/S WAY MUCH FASTER INTO
CENTRAL INDIANA ATTM. HAVE UPDATED MOST OF THE TERMINALS TO DEPICT
A QUICKER TIMING OF LOWERING OF CLOUD BASES AND INTRODUCE RAIN.
ATTM...FREEZING RAIN CANNOT BE RULED OUT AS TEMP HOVER AOB THE
FREEZING MARK AT THE SURFACE...BUT THESE SHOULD WARM A FEW DEGREES
IN THE NEXT FEW HOURS BEFORE THE BULK OF THE PRECIP ARRIVES SO
HAVE THEREFORE OMITTED ANY MENTION OF FZRA FOR NOW. PREVIOUS
DISCUSSION FOLLOWS.
EXPECTING CEILINGS GENERALLY ABOVE 050 FOR THE MOST PART
TODAY...UNTIL THE LATE AFTERNOON HOURS...WHEN DEEPER MOISTURE/LIFT
FROM THE SOUTHERN PLAINS BEGINS MOVING INTO THE AREA. CEILINGS
EXPECTED TO FALL INTO THE 040-050 RANGE BY THEN OVER THE SOUTHERN
TAF SITES. APPEARS SOME LIGHT PRECIPITATION MAY BEGIN AFFECTING
KHUF/KBMG/KIND AFTER ABOUT 252000Z. THICKNESSES SUGGEST
RAIN...HOWEVER THERE IS SOME POTENTIAL FOR SURFACE TEMPERATURES TO
COOL TO FREEZING AT SOME POINT AFTER THE ONSET OF PRECIPITATION...ESPECIALLY
AF KHUF/KIND WHERE PROGGED SURFACE WET BULB TEMPERATURES ARE AT OR
VERY CLOSE TO FREEZING. THIS MAY LEAD TO A PERIOD OF FREEZING RAIN.
SURFACE WINDS UNDER 10 KTS EXPECTED AT THE TAF SITES THROUGH 260000Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...AB/JK
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1133 PM CST TUE JAN 24 2012
.AVIATION...
GENERALLY VFR CONDITIONS WITH PERIODS OF MVFR CONDITIONS DUE TO
GROUND FOG BETWEEN 06-14Z TONIGHT. SCATTERED TO BROKEN COVERAGE OF
MID TO HIGH CLOUDS TO STREAM ACROSS THE AREA INTO EARLY AFTERNOON
ON WEDNESDAY FROM SOUTH PLAINS DISTURBANCE. WINDS TO BE LIGHT TO
CALM UNTIL 14Z THAT SUPPORTS SOME TERMINALS VISIBILITIES TO DROP
TO 2-5 MILES IN FOG. VEIL OF HIGH CLOUDS SUGGESTS DENSE FOG IS NOT
LIKELY BY NOT ALLOWING FOR GOOD RADIATIONAL COOLING. VISIBILITIES
TO IMPROVE BY MID TO LATE MORNING IF NOT ALREADY 7 MILES TO 7 PLUS
MILES AS SE TO E WINDS OF 5-10 MPH OCCUR. ..NICHOLS..
&&
.PREV DISCUSSION... /ISSUED 310 PM CST MON JAN 24 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN OCCLUDED EXTRATROPICAL CYCLONE OVER JAMES BAY
WITH AN 850MB COLD FRONT INTO THE OHIO VALLEY AND BACK INTO NORTHERN
MISSOURI. A RESPECTABLE SHORTWAVE WAS MOVING EAST OUT OF THE CENTRAL
ROCKIES WHILE ANOTHER STRONG STORM SYSTEM ORGANIZES OVER NEW MEXICO.
SATELLITE TRENDS THROUGH MID AFTERNOON SHOW CLEARING BEHIND A
DEPARTING SHORTWAVE ACROSS THE WESTERN GREAT LAKES WHILE MOISTURE
REMAINS TRAPPED UNDER THE INVERSION ACROSS IOWA. HIGH AND MID CLOUDS
WERE STREAMING EAST FROM THE PLAINS IN ADVANCE OF THE SYSTEMS IN THE
CENTRAL AND SOUTHERN ROCKIES.
18Z SFC ANALYSIS HAS HIGH PRESSURE FROM MINNESOTA THROUGH CENTRAL
IOWA AND THEN INTO THE LOWER MISSISSIPPI VALLEY. A WEAK LOW WAS
NORTH OF KVTN WITH TROFS EXTENDING NORTH AND SOUTH OF IT. THE
SOUTHERN STREAM STORM SYSTEM WAS IN THE BIG BEND OF TEXAS. DEW
POINTS WERE IN THE TEENS AND 20S ACROSS MUCH OF THE MIDWEST AND
PLAINS WITH 30S AND HIGH DEW POINTS FROM THE OHIO VALLEY WEST INTO
THE SOUTHERN PLAINS.
SHORT TERM...TONIGHT AND WEDNESDAY...
BASED ON SATELLITE CLOUDS TRENDS...THOSE AREAS THAT ARE STILL CLOUDY
WILL LIKELY REMAIN SO THROUGH SUNSET. THE PROXIMITY OF THE SFC RIDGE
COMBINED WITH THE ARRIVAL OF HIGH CLOUDS SHOULD KEEP THOSE CLOUDS IN
PLACE THROUGH SUNSET.
UNFORTUNATELY...THE STRAIGHT FORWARD FCST OF DRY CONDITIONS FOR
TONIGHT/WEDNESDAY HAS BECOME MORE COMPLICATED.
STRONG WAA FROM THE SFC TO 850MB IS OCCURRING IN THE PLAINS FROM A
LLJ WHICH IS RESULTING IN CONVERGENCE ACROSS NORTHERN KS/SOUTHERN NE
WHICH IS AIDING IN CLOUD DEVELOPMENT. RUC TRENDS IN WHICH THE
WRF/GFS AGREE SHOWS 850-700MB AND EVENTUALLY 1000-850MB CONDENSATION
PRESSURE DEFICITS LOWERING LATER THIS AFTERNOON DUE TO STRONG
FRONTOGENETICAL FORCING INDICATING PRECIPITATION. TRENDS FROM THE
RUC AND OTHER MODELS ARE TO MOVE THIS WING OF WAA PRECIPITATION INTO
IOWA THIS EVENING WITH A NORTHEAST MOVEMENT OVERNIGHT. THE HEAVY
RAIN AND LIFT TOOLS SHOW A SIMILAR SIGNAL. IF SUCH A SCENARIO WAS
OCCURRING ROUGHLY 5 MONTHS FROM NOW THESE SIGNALS WOULD POINT TO AN
MCS DEVELOPING IN THE PLAINS AND MOVING NORTHEAST.
THE WRF/GFS SHOW THE LOWEST 850-700MB CONDENSATION PRESSURE DEFICITS
JUST MISSING THE CWFA VERY LATE TONIGHT AND WEDNESDAY MORNING. THE
1000-850MB CONDENSATION PRESSURE DEFICITS ARE HIGHER SUGGESTING
ENOUGH DRY AIR WOULD BE IN PLACE TO PREVENT ANY PRECIPITATION FROM
HAPPENING. HOWEVER...SINCE THE MODELS ARE NOT HANDLING THE CURRENT
LOW CLOUDS ONE MUST BE CAUTIOUS ON THIS ASSUMPTION. GIVEN THE TRENDS
OF THE 18Z WRF RUN...WILL GO WITH THE IDEA THAT THE CWFA WILL REMAIN
DRY TONIGHT. HOWEVER...I WOULD NOT BE SURPRISED IF FLURRIES
DEVELOPED FROM HWY 20 ON NORTH AFTER 3 AM.
TEMPERATURES SHOULD QUICKLY DROP WITH SUNSET IN THE CLEAR AREAS THIS
EVENING. AS THE HIGH AND MID LEVEL CLOUDS ARRIVE THE DROP OFF SHOULD
LEVEL OFF AND MAY EVEN BEGIN A SLOW RISE THROUGH SUNRISE.
WEDNESDAY...FLURRIES MAY OR MAY NOT BE OCCURRING ALONG/NORTH OF HWY
20 DURING THE MORNING HOURS. OTHERWISE...DRY CONDITIONS WILL BE SEEN
THROUGH THE MORNING WITH PLENTY OF CLOUDS. WEDNESDAY AFTERNOON...THE
PRECIPITATION SHIELD FROM THE SOUTHERN STREAM SYSTEM WILL APPROACH
THE CWFA. CONDENSATION PRESSURE DEFICITS AND THE OVERALL FORCING
SUGGESTS THE NORTHERN LIMIT OF PRECIPITATION SHOULD BE FROM JUST
SOUTH OF KUIN TO ABOUT KAAA IN CENTRAL ILLINOIS. THUS DRY CONDITIONS
ARE EXPECTED ACROSS THE AREA DURING THE AFTERNOON HOURS.
08..
LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...FORECAST FOCUS
ON A SERIES OF SHORT WAVES MOVING THROUGH THE NORTHWEST FLOW BUT NO
SIGNIFICANT PRECIPITATION EXPECTED AT THIS TIME. TEMPERATURES TO
REMAIN A BIT ABOVE NORMAL BUT A SHOT OF COLDER AIR THIS WEEKEND.
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...SPLIT FLOW INITIALLY KEEPS
SOUTHERN STORM SYSTEM SOUTH OF THE DVN CWA AT MID WEEK.
ECM/GFS/NAM/GEM/UKMET ALL KEEP THE PRECIPITATION ASSOCIATED WITH
THIS SYSTEM SOUTH AND EAST OF THE CWA. PHASING TAKES PLACE CRANKING
UP A DECENT CYCLONE MOVING THROUGH THE OHIO VALLEY AND INTO NEW
ENGLAND LATE THIS WEEK. IN THE WAKE OF THIS SYSTEM NORTHWEST FLOW
TAKES OVER WITH A STRONG TROUGH DIVING INTO THE REGION FRIDAY AND
FRIDAY NIGHT. MOISTURE WILL BE LIMITED BUT ECM/NAM PAINTS THE
POTENTIAL FOR UP TO AN INCH OF SNOWFALL IN OUR SOUTHERN CWA. THE
GFS/GEM ARE MUCH DRIER. HOWEVER THE LOCATION OF THE AXIS OF THIS
SNOWFALL MAY CHANGE DEPENDING ON THE TRACK AND INTENSITY OF A STRONG
VORT MAX EXPECTED TO TRACK ACROSS THE AREA. MAX TEMPERATURES DURING
THIS TIME FRAME SHOULD BE IN THE 30S TO AROUND 40.
THIS WEEKEND...FOLLOWING THE PASSAGE OF THIS TROUGH COLDER AIR DUMPS
INTO THE MIDWEST. WILL BE BRISK ON SATURDAY WITH NORTHWEST WINDS
GUSTING TO 30 MPH PUTTING A BITE IN THE AIR. ANOTHER STRONG TROUGH
AND VORT MAX ARRIVES SATURDAY NIGHT BUT MOISTURE WILL BE EVEN MORE
LIMITED. HOWEVER SCATTERED FLURRIES ARE POSSIBLE DUE TO THE STRENGTH
OF THE SYSTEM BUT FOR NOW WILL NOT MENTION IN THE GRIDS WITH LOW
CONFIDENCE. MIN TEMPS SATURDAY NIGHT WILL DIP TO AROUND 10 ABOVE AT
INDEPENDENCE WITH MOST LOCATIONS IN THE TEENS. COLD ON SUNDAY WITH
MAX TEMPS ONLY IN THE 20S...BUT LOWER 30S IN OUR FAR SOUTH.
EARLY NEXT WEEK...ZONAL FLOW RETURNS WITH MILDER TEMPERATURES
REACHING INTO THE MID 30S NORTH TO MID 40S SOUTH. WAVE IN THE FLOW
TUESDAY INTO TUESDAY NIGHT MAY BRING A ROUND OF LIGHT RAIN TO THE
CWA...POSSIBLY CHANGING TO LIGHT SNOW AT THE TAIL END. THIS IS A
WEEK AWAY SO CONFIDENCE IN THE INTENSITY/TIMING AND QPF IS LOW.
HAASE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1133 AM CST WED JAN 25 2012
.AVIATION...
FOR THE 18Z TAF ISSUANCE...
WITH THE EXCEPTION OF A FEW HIGH CLOUDS...MOSTLY CLEAR SKIES AND
DRY CONDITIONS WILL PREVAIL THIS AFTERNOON THROUGH TOMORROW.
WINDS WILL GENERALLY BE FROM THE NORTH NORTHWEST AROUND 10 KNOTS
INCREASING TO 10 TO 15 KNOTS BEFORE SUNRISE. THE INCREASE IN WIND
IS DUE TO A WEAK COLD FRONT MOVING THROUGH THE AREA.
&&
.PREV DISCUSSION... /ISSUED 536 AM CST WED JAN 25 2012/
SHORT TERM...
AT 00Z WEDNESDAY A 500MB UPPER LOW WAS LOCATED NEAR EL PASO
TEXAS. NORTH OF THIS UPPER LOW A 700MB BAROCLINIC ZONE EXTENDED
ACROSS EASTERN COLORADO. AS OF 6Z THE RUC AND NAM INDICATED THAT THIS
700MB BAROCLINIC WAS CURRENTLY MOVING EAST ACROSS WESTERN KANSAS
WITH SATELLITE LOOP INDICATING WARMING CLOUD TOPS AS THIS
BAROCLINIC ZONE PASSES. CLEAR SKIES HAD ALREADY DEVELOPED WEST OF
THE 500MB DEFORMATION ZONE WHICH AT 06Z WAS STARTING TO CROSS INTO
WESTERN KANSAS. THE LIGHT PRECIPITATION THAT HAD DEVELOPED OVER
PORTIONS OF SOUTH CENTRAL KANSAS EARLIER TONIGHT WILL SLOWLY SHIFT
SOUTHEAST THROUGH THE REMAINDER OF THE MORNING AS THE MID LEVEL
BAROCLINIC ZONE CROSSES INTO SOUTH CENTRAL KANSAS BETWEEN 09Z AND 12Z
WEDNESDAY. CLOUD COVER WILL ALSO GRADUALLY GIVE WAY TO CLEAR SKIES
BY MID DAY IN THE SOUTHEAST AS THE 500MB DEFORMATION EXITS THE
AREA BASED ON 00Z NAM AND 06Z RUC.
THE NAM AND GFS MODEL SOUNDINGS AT 00Z THURSDAY, AS WELL AS ECMWF
6HOUR MAX TEMPERATURE FORECAST WERE ALL SUGGESTING THAT HIGHS
TODAY WILL REBOUND BACK INTO THE LOWER 50S ACROSS WESTERN KANSAS.
IN THE EAST WHERE CLOUDS WILL BE SLOWER TO ERODE THE HIGHS ARE
EXPECTED TO CLIMB TO AROUND 50 BUT IF SKIES CLEAR SOONER IT COULD
BE SEVERAL DEGREES WARMER BASED ON THE 875MB MIX DOWN TEMPERATURE.
TONIGHT A WEAK FRONT WILL MOVE INTO WESTERN KANSAS AS AN UPPER
LEVEL SHORT WAVE TROUGH WHICH WAS ASSOCIATED WITH THE LEFT EXIT
REGION OF A 250MB JET STREAK THAT LOCATED ACROSS WASHINGTON STATE
AT 00Z WEDNESDAY QUICKLY CROSSES THE NORTHERN PLAINS. THE
925-850MB 24HR TEMPERATURE CHANGE FROM 00Z THURSDAY TO 00Z FRIDAY
WAS ONLY A FEW DEGREES OF EACH OTHER SO GIVEN LIMITED CLOUD COVER
EXPECTED THURSDAY AFTERNOON WILL FAVOR HIGHS VERY SIMILAR THOSE
TODAY IN THE WEST. EAST/SOUTHEAST OF DODGE CITY HOWEVER GIVEN MORE
SUN AND BETTER MIXING POTENTIAL THE HIGH SHOULD BE A LITTLE WARMER
BASED ON THE FORECAST 00Z FRIDAY MODEL SOUNDINGS.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
FRIDAY WILL BE BREEZY AT LEAST AND PROBABLY WINDY AS A COLD FRONT
SWEEPS THROUGH THE AREA IN THE MORNING. NORTHWEST FLOW ALOFT WILL BE
INCREASING WITH TIME AS WELL AS THE UPPER JET FROM THE WEST COAST
RIDGE MOVES INTO THE CENTRAL HIGH PLAINS. THE FAST MOVING FRONT
SHOULD BRING A COOLER AIRMASS SOUTHWARD ALONG WITH WEAK FRONTOGENESIS
BUT THE MOISTURE APPEARS RATHER LIMITED. THE BEST QPF FIELDS IN THE
NUMERICAL MODELS LOOK TO BE BETTER ASSOCIATED WITH THE UPPER JET`S
LEFT FRONT EXIT REGION ACROSS THE MISSOURI VALLEY, AND THE BETTER
UPSLOPE FLOW/HIGHER TERRAIN OF EASTERN COLORADO. THEREFORE WE ARE
NOT IMPRESSED WITH PRECIPITATION CHANCES, AND WILL LEAVE THE 20
PERCENT CHANCES FOR RAIN OF FRIDAY ACROSS PORTIONS OF THE FORECAST
AREA. SURFACE HIGH PRESSURE SHOULD THEN DRIFT INTO NORTHERN TEXAS
AND OKLAHOMA ON SATURDAY , WHICH WOULD PRODUCE A LIGHT WESTERLY WIND
FIELD OVER SOUTHWEST KANSAS, AND SIMILAR TEMPERATURES ON BOTH DAYS
IN THE 40S. DUE TO THE LACK OF MOISTURE, THERE DOESN`T APPEAR TO BE
SIGNIFICANT CLOUD COVER DURING THIS PERIOD, BUT WITH THE UPPER JET
BUCKLED ACROSS THE PLAINS, SOME CS MIGHT BE EXPECTED. OVERNIGHT
TEMPERATURES WILL EASILY FALL BELOW FREEZING GIVEN THE COLD 850 MB
TEMPERATURE FIELDS AND THE RELATIVELY LIGHT WINDS. THE SYNOPTIC
PATTERN WILL CHANGE HEADING INTO THE LATER PART OF THE WEEKEND AS
THE UPPER WEST COAST RIDGE PUSHES FARTHER EAST AND THE LEAD UPPER
JET DIVES INTO THE MISSOURI VALLEY. THAT WILL DRAW WARMER AIR FROM
THE HIGHER TERRAIN OF NEW MEXICO AND COLORADO SUNDAY NIGHT AND INTO
MONDAY AND ALLOW TEMPERATURES TO WARM BY ABOUT 10-20 DEGREES DURING
THE DAYTIME HEADING INTO MONDAY AFTERNOON AND ESPECIALLY TUESDAY.
BOTH MODELS PRODUCE A SHORTWAVE TROUGH MOVING THROUGH THE AREA ON
MONDAY, IN A DRY AND STABLE ATMOSPHERE WHICH WILL MAINLY BRING ABOUT
A SURFACE WIND SHIFT DURING THE DAY FROM SOUTHEAST TO NORTHWEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 52 28 45 / 0 0 0 10
GCK 26 51 28 45 / 0 0 0 10
EHA 31 51 28 45 / 0 0 0 10
LBL 28 53 27 48 / 0 0 0 10
HYS 26 52 28 42 / 0 0 10 20
P28 30 55 28 48 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN12/42/42
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
536 AM CST WED JAN 25 2012
.UPDATE...
.AVIATION..../FOR THE 12Z TAF ISSUANCE/
INFRARED SATELLITE IMAGERY AND REGIONAL METAR OBSERVATIONS INDICATE
MAINLY CLEAR SKY CONDITIONS PREVAILING ACROSS THE FORECAST AREA
(INCLUDING HYS,DDC AND GCK) THIS MORNING. THIS IS A RESULT OF AN
EASTWARD EXITING MID LEVEL WAVE FROM THE SOUTHERN PLAINS AND
INCREASING HIGH PRESSURE AT THE SURFACE FROM THE HIGH PLAINS OF
COLORADO. THE DRY WEAK NORTHWEST SURFACE FLOW PATTERN IS EXPECTED TO
PERSIST THROUGH THIS TAF PERIOD. A SLIGHT INCREASE IN WIND SPEEDS TO
ABOVE 12 KNOTS IS EXPECTED BY AROUND 09 UTC THURSDAY AS MOMENTUM
TRANSFER INCREASES SLIGHTLY FROM INCREASED DEEP LAYER FLOW OVER THE
NORTHERN HIGH PLAINS. THIS IS SUPPORTED BY MUCH OF THE VARIOUS MODEL
OUTPUT AND LOCAL GFS MOS GUIDANCE.
&&
.PREV DISCUSSION... /ISSUED 251 AM CST WED JAN 25 2012/
DISCUSSION...
SHORT TERM...
AT 00Z WEDNESDAY A 500MB UPPER LOW WAS LOCATED NEAR EL PASO
TEXAS. NORTH OF THIS UPPER LOW A 700MB BAROCLINIC ZONE EXTENDED
ACROSS EASTERN COLORADO. AS OF 6Z THE RUC AND NAM INDICATED THAT THIS
700MB BAROCLINIC WAS CURRENTLY MOVING EAST ACROSS WESTERN KANSAS
WITH SATELLITE LOOP INDICATING WARMING CLOUD TOPS AS THIS
BAROCLINIC ZONE PASSES. CLEAR SKIES HAD ALREADY DEVELOPED WEST OF
THE 500MB DEFORMATION ZONE WHICH AT 06Z WAS STARTING TO CROSS INTO
WESTERN KANSAS. THE LIGHT PRECIPITATION THAT HAD DEVELOPED OVER
PORTIONS OF SOUTH CENTRAL KANSAS EARLIER TONIGHT WILL SLOWLY SHIFT
SOUTHEAST THROUGH THE REMAINDER OF THE MORNING AS THE MID LEVEL
BAROCLINIC ZONE CROSSES INTO SOUTH CENTRAL KANSAS BETWEEN 09Z AND 12Z
WEDNESDAY. CLOUD COVER WILL ALSO GRADUALLY GIVE WAY TO CLEAR SKIES
BY MID DAY IN THE SOUTHEAST AS THE 500MB DEFORMATION EXITS THE
AREA BASED ON 00Z NAM AND 06Z RUC.
THE NAM AND GFS MODEL SOUNDINGS AT 00Z THURSDAY, AS WELL AS ECMWF
6HOUR MAX TEMPERATURE FORECAST WERE ALL SUGGESTING THAT HIGHS
TODAY WILL REBOUND BACK INTO THE LOWER 50S ACROSS WESTERN KANSAS.
IN THE EAST WHERE CLOUDS WILL BE SLOWER TO ERODE THE HIGHS ARE
EXPECTED TO CLIMB TO AROUND 50 BUT IF SKIES CLEAR SOONER IT COULD
BE SEVERAL DEGREES WARMER BASED ON THE 875MB MIX DOWN TEMPERATURE.
TONIGHT A WEAK FRONT WILL MOVE INTO WESTERN KANSAS AS AN UPPER
LEVEL SHORT WAVE TROUGH WHICH WAS ASSOCIATED WITH THE LEFT EXIT
REGION OF A 250MB JET STREAK THAT LOCATED ACROSS WASHINGTON STATE
AT 00Z WEDNESDAY QUICKLY CROSSES THE NORTHERN PLAINS. THE
925-850MB 24HR TEMPERATURE CHANGE FROM 00Z THURSDAY TO 00Z FRIDAY
WAS ONLY A FEW DEGREES OF EACH OTHER SO GIVEN LIMITED CLOUD COVER
EXPECTED THURSDAY AFTERNOON WILL FAVOR HIGHS VERY SIMILAR THOSE
TODAY IN THE WEST. EAST/SOUTHEAST OF DODGE CITY HOWEVER GIVEN MORE
SUN AND BETTER MIXING POTENTIAL THE HIGH SHOULD BE A LITTLE WARMER
BASED ON THE FORECAST 00Z FRIDAY MODEL SOUNDINGS.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
FRIDAY WILL BE BREEZY AT LEAST AND PROBABLY WINDY AS A COLD FRONT
SWEEPS THROUGH THE AREA IN THE MORNING. NORTHWEST FLOW ALOFT WILL BE
INCREASING WITH TIME AS WELL AS THE UPPER JET FROM THE WEST COAST
RIDGE MOVES INTO THE CENTRAL HIGH PLAINS. THE FAST MOVING FRONT
SHOULD BRING A COOLER AIRMASS SOUTHWARD ALONG WITH WEAK FRONTOGENESIS
BUT THE MOISTURE APPEARS RATHER LIMITED. THE BEST QPF FIELDS IN THE
NUMERICAL MODELS LOOK TO BE BETTER ASSOCIATED WITH THE UPPER JET`S
LEFT FRONT EXIT REGION ACROSS THE MISSOURI VALLEY, AND THE BETTER
UPSLOPE FLOW/HIGHER TERRAIN OF EASTERN COLORADO. THEREFORE WE ARE
NOT IMPRESSED WITH PRECIPITATION CHANCES, AND WILL LEAVE THE 20
PERCENT CHANCES FOR RAIN OF FRIDAY ACROSS PORTIONS OF THE FORECAST
AREA. SURFACE HIGH PRESSURE SHOULD THEN DRIFT INTO NORTHERN TEXAS
AND OKLAHOMA ON SATURDAY , WHICH WOULD PRODUCE A LIGHT WESTERLY WIND
FIELD OVER SOUTHWEST KANSAS, AND SIMILAR TEMPERATURES ON BOTH DAYS
IN THE 40S. DUE TO THE LACK OF MOISTURE, THERE DOESN`T APPEAR TO BE
SIGNIFICANT CLOUD COVER DURING THIS PERIOD, BUT WITH THE UPPER JET
BUCKLED ACROSS THE PLAINS, SOME CS MIGHT BE EXPECTED. OVERNIGHT
TEMPERATURES WILL EASILY FALL BELOW FREEZING GIVEN THE COLD 850 MB
TEMPERATURE FIELDS AND THE RELATIVELY LIGHT WINDS. THE SYNOPTIC
PATTERN WILL CHANGE HEADING INTO THE LATER PART OF THE WEEKEND AS
THE UPPER WEST COAST RIDGE PUSHES FARTHER EAST AND THE LEAD UPPER
JET DIVES INTO THE MISSOURI VALLEY. THAT WILL DRAW WARMER AIR FROM
THE HIGHER TERRAIN OF NEW MEXICO AND COLORADO SUNDAY NIGHT AND INTO
MONDAY AND ALLOW TEMPERATURES TO WARM BY ABOUT 10-20 DEGREES DURING
THE DAYTIME HEADING INTO MONDAY AFTERNOON AND ESPECIALLY TUESDAY.
BOTH MODELS PRODUCE A SHORTWAVE TROUGH MOVING THROUGH THE AREA ON
MONDAY, IN A DRY AND STABLE ATMOSPHERE WHICH WILL MAINLY BRING ABOUT
A SURFACE WIND SHIFT DURING THE DAY FROM SOUTHEAST TO NORTHWEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 27 52 28 / 0 0 0 0
GCK 52 26 51 28 / 0 0 0 0
EHA 52 31 51 29 / 0 0 0 0
LBL 53 28 53 27 / 0 0 0 0
HYS 50 26 52 28 / 0 0 0 10
P28 51 30 55 28 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
251 AM CST WED JAN 25 2012
.DISCUSSION...
.SHORT TERM...
AT 00Z WEDNESDAY A 500MB UPPER LOW WAS LOCATED NEAR EL PASO
TEXAS. NORTH OF THIS UPPER LOW A 700MB BAROCLINIC ZONE EXTENDED
ACROSS EASTERN COLORADO. AS OF 6Z THE RUC AND NAM INDICATED THAT THIS
700MB BAROCLINIC WAS CURRENTLY MOVING EAST ACROSS WESTERN KANSAS
WITH SATELLITE LOOP INDICATING WARMING CLOUD TOPS AS THIS
BAROCLINIC ZONE PASSES. CLEAR SKIES HAD ALREADY DEVELOPED WEST OF
THE 500MB DEFORMATION ZONE WHICH AT 06Z WAS STARTING TO CROSS INTO
WESTERN KANSAS. THE LIGHT PRECIPITATION THAT HAD DEVELOPED OVER
PORTIONS OF SOUTH CENTRAL KANSAS EARLIER TONIGHT WILL SLOWLY SHIFT
SOUTHEAST THROUGH THE REMAINDER OF THE MORNING AS THE MID LEVEL
BAROCLINIC ZONE CROSSES INTO SOUTH CENTRAL KANSAS BETWEEN 09Z AND 12Z
WEDNESDAY. CLOUD COVER WILL ALSO GRADUALLY GIVE WAY TO CLEAR SKIES
BY MID DAY IN THE SOUTHEAST AS THE 500MB DEFORMATION EXITS THE
AREA BASED ON 00Z NAM AND 06Z RUC.
THE NAM AND GFS MODEL SOUNDINGS AT 00Z THURSDAY, AS WELL AS ECMWF
6HOUR MAX TEMPERATURE FORECAST WERE ALL SUGGESTING THAT HIGHS
TODAY WILL REBOUND BACK INTO THE LOWER 50S ACROSS WESTERN KANSAS.
IN THE EAST WHERE CLOUDS WILL BE SLOWER TO ERODE THE HIGHS ARE
EXPECTED TO CLIMB TO AROUND 50 BUT IF SKIES CLEAR SOONER IT COULD
BE SEVERAL DEGREES WARMER BASED ON THE 875MB MIX DOWN TEMPERATURE.
TONIGHT A WEAK FRONT WILL MOVE INTO WESTERN KANSAS AS AN UPPER
LEVEL SHORT WAVE TROUGH WHICH WAS ASSOCIATED WITH THE LEFT EXIT
REGION OF A 250MB JET STREAK THAT LOCATED ACROSS WASHINGTON STATE
AT 00Z WEDNESDAY QUICKLY CROSSES THE NORTHERN PLAINS. THE
925-850MB 24HR TEMPERATURE CHANGE FROM 00Z THURSDAY TO 00Z FRIDAY
WAS ONLY A FEW DEGREES OF EACH OTHER SO GIVEN LIMITED CLOUD COVER
EXPECTED THURSDAY AFTERNOON WILL FAVOR HIGHS VERY SIMILAR THOSE
TODAY IN THE WEST. EAST/SOUTHEAST OF DODGE CITY HOWEVER GIVEN MORE
SUN AND BETTER MIXING POTENTIAL THE HIGH SHOULD BE A LITTLE WARMER
BASED ON THE FORECAST 00Z FRIDAY MODEL SOUNDINGS.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/
FRIDAY WILL BE BREEZY AT LEAST AND PROBABLY WINDY AS A COLD FRONT
SWEEPS THROUGH THE AREA IN THE MORNING. NORTHWEST FLOW ALOFT WILL BE
INCREASING WITH TIME AS WELL AS THE UPPER JET FROM THE WEST COAST
RIDGE MOVES INTO THE CENTRAL HIGH PLAINS. THE FAST MOVING FRONT
SHOULD BRING A COOLER AIRMASS SOUTHWARD ALONG WITH WEAK FRONTOGENESIS
BUT THE MOISTURE APPEARS RATHER LIMITED. THE BEST QPF FIELDS IN THE
NUMERICAL MODELS LOOK TO BE BETTER ASSOCIATED WITH THE UPPER JET`S
LEFT FRONT EXIT REGION ACROSS THE MISSOURI VALLEY, AND THE BETTER
UPSLOPE FLOW/HIGHER TERRAIN OF EASTERN COLORADO. THEREFORE WE ARE
NOT IMPRESSED WITH PRECIPITATION CHANCES, AND WILL LEAVE THE 20
PERCENT CHANCES FOR RAIN OF FRIDAY ACROSS PORTIONS OF THE FORECAST
AREA. SURFACE HIGH PRESSURE SHOULD THEN DRIFT INTO NORTHERN TEXAS
AND OKLAHOMA ON SATURDAY , WHICH WOULD PRODUCE A LIGHT WESTERLY WIND
FIELD OVER SOUTHWEST KANSAS, AND SIMILAR TEMPERATURES ON BOTH DAYS
IN THE 40S. DUE TO THE LACK OF MOISTURE, THERE DOESN`T APPEAR TO BE
SIGNIFICANT CLOUD COVER DURING THIS PERIOD, BUT WITH THE UPPER JET
BUCKLED ACROSS THE PLAINS, SOME CS MIGHT BE EXPECTED. OVERNIGHT
TEMPERATURES WILL EASILY FALL BELOW FREEZING GIVEN THE COLD 850 MB
TEMPERATURE FIELDS AND THE RELATIVELY LIGHT WINDS. THE SYNOPTIC
PATTERN WILL CHANGE HEADING INTO THE LATER PART OF THE WEEKEND AS
THE UPPER WEST COAST RIDGE PUSHES FARTHER EAST AND THE LEAD UPPER
JET DIVES INTO THE MISSOURI VALLEY. THAT WILL DRAW WARMER AIR FROM
THE HIGHER TERRAIN OF NEW MEXICO AND COLORADO SUNDAY NIGHT AND INTO
MONDAY AND ALLOW TEMPERATURES TO WARM BY ABOUT 10-20 DEGREES DURING
THE DAYTIME HEADING INTO MONDAY AFTERNOON AND ESPECIALLY TUESDAY.
BOTH MODELS PRODUCE A SHORTWAVE TROUGH MOVING THROUGH THE AREA ON
MONDAY, IN A DRY AND STABLE ATMOSPHERE WHICH WILL MAINLY BRING ABOUT
A SURFACE WIND SHIFT DURING THE DAY FROM SOUTHEAST TO NORTHWEST.
&&
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
VFR CEILINGS WILL PERSIST THROUGH THE LATE NIGHT HOURS BUT SHOULD BE
MOVING EAST OF THE TAF SITES BY 12Z. LIGHT RAIN SHOULD REMAIN SOUTHEAST
OF DODGE CITY THROUGH THE NEXT FEW HOURS ALTHOUGH A FEW SPRINKLES
COULD OCCUR. NORTH WINDS WILL BE GUSTY AT TIMES TO 20-25 KNOTS BUT
SHOULD ALSO BE DECREASING BY 12Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 27 52 28 / 0 0 0 0
GCK 51 26 51 28 / 0 0 0 0
EHA 51 31 51 29 / 0 0 0 0
LBL 51 28 53 27 / 0 0 0 0
HYS 50 26 52 28 / 0 0 0 10
P28 50 30 54 28 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN18/33/02
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
633 PM EST THU JAN 26 2012
.SYNOPSIS...
RAIN TONIGHT, AS LOW PRESSURE SLOWLY MOVES THROUGH THE UPPER OHIO
VALLEY. THE RISK FOR SHOWERS WILL CONTINUE ON FRIDAY. PORTIONS OF
THE AREA MAY SEE THE RAIN SHOWERS END AS SNOW SHOWERS AS COLDER
AIR WRAPS IN BEHIND THE EXITING LOW.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
RAIN IS AGAIN OVERSPREADING THE AREA. THIS NEXT BATCH IS
DEVELOPING ALONG THE NORTHERN EDGE OF AN UPPER LEVEL WAVE, AND
ALONG A TIGHT WARM FRONT. CURRENTLY, LARGE DIFFERENCES IN SFC
TEMPS, WITH THE NORTHERN REACHES OF MY AREA REPORTING TEMPS IN THE
MID 30S, WHILE THE SOUTH IS SEEING TEMPS IN THE MID 50S. EXPECT
THIS PUSH OF WARMER AIR TO CONTINUE OVERNIGHT, WHICH WILL MEAN
SLOWLY RISING TEMPS ACROSS THE NORTH AND NEARLY STEADY TEMPS
ACROSS THE SOUTH.
RAIN WILL CONTINUE TO FILL IN FROM THE SOUTHWEST AS A DEEPENING
SURFACE LOW MOVES OVER W PA BY MIDNIGHT. PLENTY OF LOW AND MID
LEVEL MOISTURE IS BEING PUMPED INTO THE SYSTEM, WITH STRONG
SOUTHWESTERLY 85H JET. IN ADDITION TO THE STRONG JET, MODELS ARE
ALSO SHOWING ENHANCED LOW/MID LEVEL CONVERGENCE ALONG THE FRONTAL
BOUNDARY. THERE STILL REMAIN SOME DIFFERENCES ON THE PLACEMENT OF
THE AXIS OF HEAVY RAIN. CURRENT HIRES MODEL DATA IS SHOWING THE
AXIS OVER FAR WESTERN COUNTIES EXTENDING NORTHWARD INTO NW PA.
THIS LINES UP PRETTY WELL WITH THE 18Z NAM SOLUTION. THIS MAKES
SENSE WITH THE STRONG WARM SURGE PUSHING THE WARM FRONTAL BOUNDARY
FURTHER NORTH.
USING LATEST MODEL DATA, WOULD EXPECT A GENERAL .50 TO .75 INCHES
OF RAIN FOR THE REMAINDER OF THE NIGHT, WITH UP TO AN INCH POSSIBLE
IN THE WEST AND NORTH. THERE IS A WRENCH IN THE SETUP, WHICH IS
CURRENTLY MOVING NORTHWARD ACROSS TN AND KY. A LARGE DRY SLOT IS
DEVELOPING ON THE SOUTHERN EDGES OF THE SFC LOW. 18Z NAM IS
PICKING UP THIS FEATURE PRETTY WELL, MOVING IT THROUGH THE AREA
AFTER 06Z. THE LATEST HRRR IS ALSO HINTING AT THIS, WITH A
DECREASE IN RAINFALL COVERAGE AND INTENSITY AFTER 06Z. IF THIS DRY
SLOT HOLDS TOGETHER, IT WILL LOWER RAINFALL AMOUNTS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
SFC WAVE WILL PICK UP SPEED FRIDAY MORNING AND MOVE INTO NY STATE.
THIS WILL BE IN CORRELATION WITH THE UL TROUGH DIGGING INTO W OHIO.
THE EXITING LOW WILL BRING AN END TO THE SHOWER ACTIVITY FRIDAY
MORNING. HOWEVER, THIS WILL BE SHORT LIVED, AS THE TROUGH WILL
SWING THROUGH BY EARLY AFTERNOON. EXPECT ANOTHER AREA OF SHOWERS
TO DEVELOP WITH THE UL WAVE. NOT A GREAT DEAL OF COLD AIR
ASSOCIATED WITH THE TROUGH, AND IT TAKES SOME TIME FOR THE LOWEST
LEVELS TO COOL. SO THINK MOST LOCATIONS WILL SEE MAINLY RAIN
SHOWERS, THAT WILL AT TIMES MIX WITH SNOW SHOWERS. A COMPLETE
CHANGE OVER WILL LIKELY OCCUR ON THE BACKSIDE OF THE TROUGH.
THE UL WAVE WILL SHIFT INTO E PA BY LATE AFTERNOON.
TEMPS WILL BE TRICKY. EXPECT MORNING HIGHS WITH TEMPS SLOWLY
FALLING THROUGHOUT THE DAY.
RIDGING WILL BRIEFLY MOVE IN FRIDAY NIGHT...BUT WILL BE PUSHED
OUT BY LOW PRESSURE OVER LAKE HURON ON SATURDAY. HAVE BUMPED UP
POPS A BIT MORE FOR THIS PERIOD. THE SAME THING SHOULD HAPPEN
SATURDAY NIGHT AND SUNDAY...WITH A BRIEF PERIOD OF RIDGING
FOLLOWED BY A CHANCE OF SHOWERS. ON SUNDAY...MOISTURE IS SLIGHTLY
DEEPER...SO HAVE ADDED SOME LIKELY POPS NORTH OF INTERSTATE 80.
PRECIP SHOULD FALL AS A MIX OF RAIN AND SNOW IN SOME LOCATIONS.
TEMPERATURES SHOULD BE A FEW DEGREES COLDER ON SUNDAY THAN
SATURDAY...BUT STILL CLOSE TO NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
GFS ENSEMBLE/ECMWF ARE IN AGREEMENT THAT AN UPPER LEVEL TROUGH WILL
SWING ACROSS THE AREA SUNDAY NIGHT WITH A NORTHWESTERLY FLOW ON
MONDAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTHWEST. MODEL
THICKNESSES ARE LOW ENOUGH FOR ALL SNOW SHOWERS SUNDAY NIGHT WHICH
ARE FORECAST TO DIMINISH BY MONDAY MORNING. HIGH PRESSURE PASSING
SOUTH OF THE AREA WILL KEEP THE FORECAST DRY MOST OF MONDAY INTO
EARLY TUESDAY. TEMPERATURES ON MONDAY WILL BE NEAR NORMAL SEASONAL
VALUES.
A FRONTAL BOUNDARY WILL APPROACH THE AREA FROM THE NORTHWEST ON
TUESDAY AND CROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY. THIS WILL
BRING A MIX OF RAIN AND SNOW SHOWERS, CHANGING OVER TO ALL RAIN ON
WEDNESDAY. AFTER WEDNESDAY, THERE IS UNCERTAINTY WITH AN APPROACHING
AMPLIFIED TROUGH FROM THE WEST WEDNESDAY NIGHT INTO THURSDAY. THUS,
A SCHC OF RAIN/SNOW SHOWERS IS FORECAST. TEMPERATURES WILL BE 5 TO
10 DEGREES ABOVE NORMAL FOR TUESDAY INTO THURSDAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LOW PRESSURE CROSSING ALONG/JUST N OF THE OH RIVER TNGT WL CONT TO
SPREAD RA OVR THE REGION. WARM FRONT EXTENDING FM THAT ADVNG LOW
SHIFTED TO A ZZV...PIT...IDI LINE AS OF LATE AFTN AND LIFTED
CIGS/OVRALL CONDITIONS TO VFR/TEMPO MVFR STATUS. AREA OF RA MOVG
ALNG THAT BOUNDARY WL MAINTAIN THE POTENTIAL FOR MVFR AT PORTS ALNG
S OF THAT LINE THROUGH THE EVE...
AS THE LOW DVLPS NWD IN THE PROGRESSING NGT...EXPECT RAIN TO CONT
WITH A REDETERIORATION TO IFR...AND A WIND SHIFT TO THE SW WITH
PASSAGE OF THE LOW DURING THE PREDAWN HRS. THE LOW IS PROJECTED
WELL TO THE NE ON FRIDAY...AND SHRA WL TURN TO SHSN WITH PASSAGE OF
THE SYSTEMS CDFNT. IFR CIGS ARE EXPECTED TO IMPROVE TO MVFR BY FRI
AFTN...BUT SFC WND WL BE AN INCREASING ISSUE AS GUSTS OF 20 TO 25
KTS DVLP WITH A STEEPENING LLVL LAPSE RATE IN THE WAKE OF THE FRONT.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
HIGH PRES IS FORECAST TO BLD BRIEFLY FOR A BREAK FM SHSN ON FRIDAY
NGT AND AND EARLY SATURDAY. CIG RESTRICTIONS SHOULD CONT THRU THE
WEEKEND AS A SERIES OF UPR DISTURBANCES GENERATE SHRA/SHSN FOR MOST
TERMINALS. VFR CONDITIONS ARE THEN ANTICIPATED WITH EARLY WEEK HIGH
PRES.
&&
.HYDROLOGY...
LOW PRESSURE MOVING NORTHEASTWARD ALONG THE OHIO RIVER TONIGHT
WILL PRODUCE LIGHT...TO OCCASIONALLY MODERATE RAIN ACROSS THE
UPPER OHIO VALLEY REGION. RAINFALL AMOUNTS UP TO AN ADDITIONAL
0.75 TO 1.00 INCH ARE EXPECTED OVER EAST CENTRAL OHIO. SMALL STREAM
FLOODING IS POSSIBLE FOR THESE AREAS TONIGHT AND EARLY FRIDAY.
RIVER FLOODING IS ALSO POSSIBLE ALONG THE MUSKINGUM RIVER IN THE
VICINITY OF COSHOCTON BY FRIDAY AFTERNOON.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FLOOD WATCH UNTIL 4 AM EST FRIDAY FOR OHZ039>041-048>050-
057>059-068-069.
PA...FLOOD WATCH UNTIL 4 AM EST FRIDAY FOR PAZ020-021-029-031.
WV...FLOOD WATCH UNTIL 4 AM EST FRIDAY FOR WVZ001>004-012-021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
958 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING QUIET WEATHER TODAY AS CLOUDS SLOWLY
DECREASE. A STORM SYSTEM WILL MOVE NORTHEAST FROM THE GULF COAST
FOR WEDNESDAY NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WITH 10AM UPDATE...HAVE PRIMARILY TWEAKED SKY AND TEMPERATURE
TRENDS. HAVE NOTICED THAT RECENT RUNS OF THE HRRR KEEP OVERCAST
SKIES ALL DAYS...WHICH WOULD RESULT IN LOWER HIGH TEMPERATURES
ACROSS THE REGION. IF THIS OCCURS...THERE WOULD BE A GREATER
CHANCE FOR FREEZING RAIN LATE TONIGHT. PREVIOUS DISCUSSION
FOLLOWS.
AREA OF LOW CLOUDS WILL REMAIN ACROSS REGION THROUGH THE MORNING
BUT SHOULD BEGIN TO MIX OUT MIDDAY. THESE WILL BE REPLACED BY MID
DECK LATER THIS AFTERNOON AS HIGH LEVEL MOISTURE AHEAD OF GULF
COAST SYSTEM STREAM NORTH.
TONIGHT STORM SYSTEM WILL MOVE FROM TEXAS TOWARD THE OHIO VALLEY
WHILE NORTHERN STREAM SHORTWAVE AND FRONT SLIDE NORTH OF REGION.
USED A GENERAL BLEND OF ECMWF AND NAM MODELS. APPEARS THERE WILL
BE ENOUGH COLD AIR IN PLACE FOR A POSSIBLE MIX OF FREEZING RAIN
FROM PITTSBURGH NORTH AND IN THE RIDGES AS PRECIP BEGINS. SOME
SLEET ALSO POSSIBLE I-80 CORRIDOR. STILL DOUBT ON ARRIVAL TIME OF
PRECIP, AND QPF OVERNIGHT WILL BE ON THE LIGHT SIDE. IF ARRIVAL OF
PRECIP DELAYED AS PER GFS MODEL LITTLE IF ANY FREEZING OR FROZEN
PRECIP WILL OCCUR. WILL MENTION IN HWO THAT A BRIEF PERIOD OF
FREEZING RAIN POSSIBLE OVERNIGHT. NOT ENOUGH CONFIDENCE IN ANY
SOLUTION FOR ANY HEADLINES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS LOW PRESSURE PUSHES NORTHEAST DURING THE DAY THURSDAY WARM
ADVECTION WILL WARM TEMPERATURES INTO THE 40S WITH RAIN
OVERSPREADING THE AREA AND CONTINUING INTO THURSDAY NIGHT. MODELS
STILL HAVE DIFFERENCES IN PLACEMENT OF HIGHEST QPF BUT BELIEVE A
HALF TO ONE INCH RAINFALL LIKELY SOUTHERN 2/3RDS OF CWA. WENT WITH
A CHANGEOVER TO SNOW AS PRECIP DIMINISHES LATER THURSDAY NIGHT BUT
LITTLE IF ANY ACCUMULATION EXPECTED AS DEEP MOISTURE WILL BE
EXITING BEFORE COLDER THICKNESS CAN ARRIVE. KEPT POPS IN FOR
FRIDAY WITH LEFTOVER MOISTURE IN WEST TO NORTHWEST FLOW BEHIND
SURFACE LOW.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
BLEND OF ECMWF AND NAEFS MODEL OUTPUT SHOW PACIFIC COAST RIDGING IN
THE UPPER LEVEL JETSTREAM CAUSING TROUGHING ACROSS THE CANADIAN
PLAINS THIS WEEKEND. SO EXPECT UPPER OHIO VALLEY TEMPERATURES TO GO
COLDER THAN NORMAL SUNDAY IN THE WAKE OF THE PLAINS-BRED COLD
FRONTAL PASSAGE SATURDAY. SO THE COLD FRONTAL PASSAGE SATURDAY WILL
BE ACCOMPANIED BY BOTH RAIN AND SNOW SHOWERS, BUT THEN FOLLOWED BY
SCATTERED SNOW SHOWERS SUNDAY.
EARLY NEXT WEEK, THE MODELS SHOW THE SOUTHERN JETSTREAM BRANCH
GAINING MORE INFLUENCE, AND THIS IS REFLECTED IN UPPER OHIO VALLEY
TEMPERATURES MODERATING TUESDAY AHEAD OF AN INCOMING OKLAHOMA-BRED
LOW PRESSURE SYSTEM. HENCE THE SYSTEM`S WARM FRONTAL PASSAGE TUESDAY
MAY BE ACCOMPANIED BY MIXED PRECIPITATION.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
MVFR STRATOCUMULUS CLOUDS WILL CONTINUE TO PREVAIL ACROSS THE
TERMINALS THROUGH THE EARLY AFTERNOON HOURS. SREF/LAMP GUIDANCE
SUPPORT MVFR CLOUDS ERODING FROM THE SOUTH AFTER 18Z AND REACHING
KFKL AND KDUJ BY 21Z. HIGH CIRRUS WILL THEN FILTER ACROSS THE
TERMINALS WITH VFR CONDITIONS PREVAILING EARLY TONIGHT.
CEILINGS WILL RETURN AND LOWER TO MVFR AFTER 06Z THURSDAY AS SHOWERS
PUSH INTO THE TERMINALS WELL AHEAD OF A FRONTAL BOUNDARY ACROSS THE
TENNESSEE VALLEY. FORECAST CONSISTS OF ALL RAIN AT THIS POINT,
ALTHOUGH THERE IS LOW CONFIDENCE THAT A BRIEF PERIOD OF FREEZING
RAIN WILL BE POSSIBLE NEAR DAWN, ESPECIALLY NORTH OF A KAGC-KLBE
LINE.
WINDS WILL GENERALLY REMAIN LIGHT...TO ABOUT 5-8KTS UNDER HIGH
PRESSURE...GRADUALLY BECOMING EASTERLY AT THE SURFACE.
OUTLOOK...THURSDAY THROUGH SUNDAY...
RAIN SHOWERS WILL CROSS THE REGION OUT AHEAD OF THE APPROACHING
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW ON THURSDAY. MIXED
PRECIPITATION AND WIDESPREAD RESTRICTIONS ARE EXPECTED FOR THURSDAY
NIGHT AND FRIDAY AS THAT TROUGH MOVES E/NEWD. MORE RESTRICTIONS ARE
POSSIBLE FOR THE WEEKEND AS THE SYSTEMS COLD FRONT GENERATES SHRA
AND SHSN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
614 PM EST THU JAN 26 2012
.SHORT TERM...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A SHOTRWAVE OVER THE NRN
PLAINS POISED TO MOVE ACROSS THE AREA TONIGHT. RADAR RETURNS SHOW A
NARROW BAND OF PCPN IN FORM OF LIGHT SNOW ASSOC WITH THIS FEATURE
OVER WRN LAKE SUPERIOR AND NW WI. ANOTHER SHORTWAVE NOW OVER THE NRN
ROCKIES IS PROGGED TO MOVE INTO THE UPR MS VALLEY AND WRN GREAT
LAKES LATE FRIDAY BRINGING ANOTHER CHC FOR LIGHT SNOW FRI AFTERNOON
AND FRI NIGHT.
800-700 MB FGEN AND MODERATE MID-LVL Q-VECT CONV ALONG FRONTAL
BOUNDARY HAS RESULTED IN BAND OF LIGHT SNOW OVER WRN LAKE SUPERIOR
AND NW WI. MODELS INDICATE FGEN FORCING AND Q-VECT CONV WILL WEAKEN
SOME ALONG THE FRONTAL PASSAGE BUT THEN STRENGTH A BIT OVER THE ERN
FCST LATER THIS EVENING AND OVERNIGHT. THUS...KEPT ONLY SLIGHT CHC
POPS FOR SNOW OVER THE WRN HALF OF THE FCST AREA THIS EVENING AND
KEPT IN 30 PCT POPS OVER THE ERN COUNTIES. CLEARING LATER THIS
EVENING AND OVERNIGHT WILL ALLOW TEMPS TO FALL INTO THE TEENS OVER
THE WRN INTERIOR WHERE TEMPS ELSEWHERE SHOULD BE MAINLY IN THE LOWER
TO MID 20S. 850 MB TEMPS BEHIND THE FRONT ARE ONLY EXPECTED TO DROP
TO -8 TO -9C WHICH SHOULD NOT BE COLD ENOUGH FOR ANY LES IN WNW FLOW
BEHIND FRONT.
RDGG MOVING OVER THE AREA WILL KEEP MUCH OF THE CWA DRY ON FRIDAY.
THE ONLY EXCEPTION WILL BE FAR WRN COUNTIES FRI AFTERNOON WHERE
SHORTWAVE APPROACHING FM THE NRN ROCKIES WILL BRING ANOTHER CHC OF
SNOW LATE IN THE DAY.
.LONG TERM DISCUSSION /FRIDAY NIGHT THROUGH THURSDAY/...
FRIDAY NIGHT THROUGH SUNDAY...
LARGE SHORTWAVE OVER JAMES BAY WILL KEEP TROUGH ACROSS THE UPPER
GREAT LAKES THROUGH SUNDAY...WITH SEVERAL WEAK AND FAST MOVING
SHORTWAVES DEVELOPING ALONG THE DESCENDING BRANCH OF THE TROUGH OVER
THE FORECAST PERIOD. THE FIRST OF THESE SHORTWAVES WILL REACH THE
CWA SATURDAY MORNING...MERGING WITH A SECONDARY SHORTWAVE TO OUR
SOUTH...WITH THE ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND PRECIP
IMPACTING THE AREA BEGINNING FRIDAY NIGHT CONTINUING DURING THE DAY
ON SATURDAY. ALL MODELS ARE PERSISTENT ON THIS IDEA...HOWEVER THERE
SEEMS TO BE SOME DISAGREEMENT BETWEEN THE NAM AND OTHER MODELS AS
FAR AS THE PLACEMENT OF THE SURFACE LOW...AND RESULTING PRECIP.
BASED ON SREF DATA ALSO TRENDING AWAY FROM GENERAL NAM
SOLUTION...HAVE DECIDED TO GO WITH CONSENSUS OF OTHER MODELS WHICH
WILL KEEP SURFACE LOW AND MAIN QVECTOR CONV TO THE SOUTH...KEEPING
MAIN PRECIP ALONG THE SOUTHERN HALF OF THE CWA...WITH SOME CHANCES
POSSIBLE ACROSS THE REMAINING CWA.
AS SYSTEM PULLS OUT SATURDAY AFTERNOON...WINDS WILL TRANSITION TO A
WNW DIRECTION AND THEN EVENTUALLY TO A MORE W DIRECTION BY SATURDAY
NIGHT...BEFORE FINALLY VEERING BACK TO THE NW BY SUNDAY MORNING
AHEAD OF NEXT APPROACHING SHORTWAVE. FALLING H850 TEMPS TO AROUND
-14C BEHIND THE ASSOCIATED COLD FRONT AND AHEAD OF A DESCENDING
POLAR JET WILL INDUCE LAKE EFFECT SNOW IN WNW FAVORED REGIONS DURING
THE DAY SATURDAY...AND THEN INTENSIFY IN AREAS FAVORED BY A NW WIND
DIRECTION DURING THE DAY SUNDAY AS H850 TEMPS BOTTOM OUT TO AROUND
-18C. POTENTIAL FOR HEAVY ACCUMULATIONS IN AFFECTED AREAS IS
POSSIBLE THROUGH THIS PERIOD/SATURDAY AFTERNOON THROUGH SUNDAY
EVENING...AS INVERSION HEIGHTS RANGE BETWEEN 5K-10K FT WITH DEEP
MOISTURE AVAILABLE AT TIMES IN THE SNOW GROWTH ZONE.
SUNDAY NIGHT THROUGH THURSDAY...
STRONG RIDGE AMPLIFICATION OVER THE WESTERN U.S. WILL ALLOW LARGE
SHORTWAVE TO REMAIN STATIONARY ACROSS HUDSON BAY...WITH A RESULTING
TROUGHING PATTERN ACROSS THE GREAT LAKES REGION. THIS SHARP TROUGH
WILL ALLOW THE POLAR JET TO DIP DOWN AS FAR SOUTH AS KENTUCKY SUNDAY
NIGHT...WHICH WILL TRANSLATE TO THE RETURN OF MUCH COLDER
TEMPERATURES TO THE REGION. H850 TEMPS OF -18C OVER THE LAKE WILL
KEEP SOME LINGERING CHANCES OF LES IN AREAS FAVORED BY NW
WINDS...QUICKLY DIMINISHING AS WAA ADVECTION COMES IN TO PLAY AND
WINDS BACK TO A MORE SW DIRECTION. AT THIS POINT/SUNDAY NIGHT/ THE
POLAR JET WILL MERGE WITH THE SUBTROPICAL JET AND MOVE
EASTWARD...WHICH WILL SLOWLY LIFT THE STATIONARY TROUGH TO THE
NORTHEAST AND RETURN MUCH OF THE US TO A MORE ZONAL FLOW BY MONDAY
NIGHT. WEAK SURFACE DISTURBANCE WILL FORM ALONG THE DESCENDING
BRANCH OF THIS SHORTWAVE...BRINGING A CHANCE FOR SYNOPTIC SNOWFALL
MONDAY...BEFORE QUICKLY MOVING OFF TO THE EAST FOLLOWING THE GENERAL
UPR LEVEL FLOW. SOME MODEL DISAGREEMENTS ON TIMING AND STRENGTH OF
THIS SHORTWAVE...WITH GFS BEING MORE PROGRESSIVE AND ECMWF BEING
SLOWER YET STRONGER...SO HAVE GONE WITH A GENERAL CONSENSUS.
THE NEXT SHORTWAVE WILL TRACK ACROSS THE AREA SOMETIME
TUESDAY/TUESDAY NIGHT NIGHT...WITH SAME DISAGREEMENT AND LOW
CONFIDENCE BETWEEN THE MODELS ON THE EXACT LOCATION AND STRENGTH.
ECMWF AND GEM ARE MORE PROGRESSIVE WITH THE ARRIVAL OF THE
SHORTWAVE...HAVING IT AMPLIFYING IT OVER THE GREAT LAKES REGION BY
TUESDAY MORNING...GFS ON THE OTHER HAND KEEPS THE LOW FARTHER TO OUR
SOUTH...PASSING ACROSS LAKE MI BY LATE TUESDAY NIGHT. DESPITE
DISAGREEMENTS ON PLACEMENT...STRONG MOISTURE AVAILABILITY/PWAT
VALUES 200 PCT ABOVE NORMAL/ AND WAA WILL BE ENOUGH TO KEEP CHANCES
OF PRECIP IN BOTH TUESDAY AND WEDNESDAY...ESPECIALLY EAST HALF OF
THE CWA. THIS AMPLIFIED TROUGH WILL ONCE AGAIN BRING SOME COLDER
TEMPERATURES IN DURING THE OVERNIGHT HOURS TUESDAY NIGHT. UPPER
GREAT LAKES SHOULD THEN TRANSITION TO A RIDGING PATTERN WITH
RELATIVELY QUIET WEATHER THROUGH THE REMAINDER OF THE FORECAST
PERIOD.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
EXPECT MVFR CIGS THIS EVENING AT KIWD WITH SOME IFR CIGS AT KSAW AND
KCMX. COLD FRONT MOVING THROUGH THIS EVENING AND ASSOC MIXING AND
DRIER AIR SHOULD ALLOW MVFR CIGS TO LIFT AND VFR CONDITIONS TO
PREVAIL BY LATE EVENING/OVERNIGHT AT ALL SITES AND THIS SHOULD
CONTINUE THROUGH THE REST OF THE FORECAST PERIOD.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT GUSTY SW WINDS TO 25 KTS INTO EARLY THIS EVENING AHEAD OF
APPROACHING TROUGH. AFTER THE TROUGH PASSES...W/WNW WINDS WILL
INCREASE TO 30 KTS...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR
THIS EVENING INTO FRI MORNING. THERE COULD BE A FEW GALE FORCE GUSTS
TO 35 KTS BUT PREVAILING WIND SPD SHOULD STAY BLO GALES. A SERIES OF
TROUGHS WILL THEN PASS THROUGH FRIDAY NIGHT THROUGH SUNDAY BEFORE
HIGH PRESSURE MOVES OVERHEAD SUN NIGHT AND MONDAY. EACH OF THESE
TROUGHS WILL BRING INCREASED WINDS...WITH A POSSIBLE PERIOD OF GALES
SAT AFTERNOON INTO SAT EVENING...MAINLY OVER THE ERN HALF OF THE
LAKE WHERE A GALE WATCH HAS BEEN ISSUED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR
LSZ265>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JMW
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
347 PM CST WED JAN 25 2012
.DISCUSSION...
TONIGHT AND THURSDAY...SFC LOW OVER SRN SASKATCHEWAN WILL CONTINUE
TO TRAVERSE EWD OVER LOWER CANADA...BEING USHERED ALONG BY AN
UPPER TROUGH EVENTUALLY BECOMING NEGATIVELY TILTED. A CDFNT
HANGING S FROM THE SFC LOW WILL PUSH THRU THE AREA ARND DAYBREAK
THU MORNING. THE MAIN EFFECTS WILL BE MAINTAINING CLOUD COVER OVER
THE AREA ALONG WITH AN INCREASE IN WIND SPEEDS DUE TO A TIGHTENED
PRESSURE GRADIENT AND ENHANCED LOW- AND MID- LEVEL JETTING.
MOISTURE IS QUITE MEAGER WITH THE FRONT IN SRN MN AND WI /BETTER
MOISTURE OVER NRN MN INTO THE UPPER GREAT LAKES/ SO AM NOT
EXPECTING ANYTHING MORE THAN POSSIBLY FLURRIES SO WILL KEEP THE
FCST DRY OVERNIGHT THRU THU. THERE IS ALSO THE POTENTIAL FOR FOG
IN FAR SRN MN THIS EVENING INTO THE EARLY MRNG HOURS...BUT
ELEVATED WINDS LOOK TO MITIGATE THOSE PROSPECTS. WINDS WILL SHIFT
TO NW BY MIDDAY TMRW AND AS THE FRONT EXITS...SFC HIGH PRES OVER
THE CENTRAL PLAINS WILL NUDGE NWD BY LATE IN THE DAY. THIS WILL
ALLOW FOR PARTIAL CLEARING LATE BUT NOT ENOUGH TO PUSH HIGHS THU
OUT OF THE MID 30S.
THURSDAY NIGHT THROUGH SATURDAY...PROGRESSIVE NWLY FLOW THU NIGHT
INTO FRI WILL DRAG A DEVELOPING COMPACT LOW PRES SYSTEM FROM THE
NRN ROCKIES ACRS THE DAKOTAS AND INTO NRN IA THU NIGHT INTO FRI
MRNG. A SWATH OF DEEPER MOISTURE WILL ACCOMPANY THE SYSTEM AND
INTENSIFY AS IT MEETS UP WITH A REGION OF ENHANCED PV. DEEP COLD
AIR WILL MAKE FOR ANY PRECIP TO BE ALL SNOW...AND WITH GOOD MODEL
AGREEMENT THAT THE PRECIP BANDS WILL BE OVER SRN MN...HAVE NUDGED
UP POPS INTO THE HIGH-END CHC AND LOW-END LIKELY CATEGORY FOR FAR
SRN MN...TRENDING TO SLGT CHC IN CENTRAL MN AND WESTERN WI. QPF/S
APPROACHING A TENTH OF AN INCH WILL PRODUCE 1-2 INCHES OF SNOW
DURING THE DAY ON FRI...PARTICULARLY FRI MORNING AND EARLY
AFTN...OVER SRN MN WITH AMOUNTS TRENDING DOWN GOING N. THE SYSTEM
QUICKLY EXITS TO THE E BY LATE DAY FRI...ALLOWING HIGH PRESSURE TO
MOVE IN FOR FRI NIGHT INTO SAT. THE PATTERN THEN STARTS TO GET A
LITTLE MESSY AS MORE DEVELOPED NW FLOW WILL WILL BRING DOWN WEAK
UPPER LEVEL DISTURBANCES STARTING MIDDAY SAT WHICH MAY BRING
FLURRIES OR LIGHT SNOW SHOWERS TO MAINLY WRN WI AND ERN MN FOR
MID-TO-LATE DAY SATURDAY. POPS ARE ONLY IN THE SLGT CHC RANGE
ATTM. WITH THE STRONGER NW FLOW WILL BE ANOTHER MODEST SURGE OF
ARCTIC AIR TO THE REGION WHICH WILL BUMP HIGHS BACK DOWN TO THE
20S AND LOWS TO THE TEENS AND UPPER SINGLE DIGITS.
SUNDAY THROUGH WEDNESDAY...THE LONGWAVE UPPER TROUGH RESPONSIBLE
FOR THE PRONOUNCED NWLY FLOW OVER THE UPPER MISSISSIPPI RIVER
VALLEY WILL SHIFT E...ALLOWING WESTERN CONUS RIDGING TO MOVE INTO
THE REGION. THIS WILL INITIALLY RESULT IN A WARMING TREND FOR THE
START OF NEXT WEEK...INCLUDING HIGHS REACHING ABOVE FREEZING FOR A
COUPLE OF PERIODS. HOWEVER...AS THE RIDGE FLATTENS...ADDITIONAL
WEAK UPPER DISTURBANCES WILL MOVE IN FROM THE WESTERN STATES. NO
ORGANIZED SYSTEMS ARE APPARENT IN ANY OF THE MODELS ATTM...SO POPS
ARE NO HIGHER THAN 20 PERCENT FOR ANY PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
SEVERAL FACTORS THIS AFTN/EVENING WILL CAUSE EITHER CIGS TO
LOWER...OR REMAIN THE SAME AS THE STRONG INVERSION CONTINUES THIS
AFTN/EVENING ACROSS ALL OF THE FA.
MAIN FORECAST CONCERN DEALS WITH ONGOING MVFR/IFR/LIFR CIGS ACROSS
WESTERN MN...AND IF THEY ADV EASTWARD THIS EVENING.
BASED ON CURRENT LOW LEVEL FLOW BLW 90H...BELIEVE MOST OF THE
LOWER CIGS ACROSS THE WEST WILL REMAIN WEST THRU 00Z...OR UNTIL
THE WNDS BECOME MORE SSW/SW OVERNIGHT WHICH WILL BRING THE LOWER
CIGS ACROSS EASTERN MN/WESTERN WI. AM LEANING TOWARD A MORE
OPTIMISTIC FORECAST FOR MSP/RNH/EAU THIS AFTN...WITH LOWER CIGS
NOT MOVING INTO THIS AREA UNTIL AFT 2Z. CONFIDENCE IS LOW ON ANY
ONE SCENARIO...ESPECIALLY SINCE WE HAVE SOME MELTING OF THE SNOW
ACROSS SC MN THIS AFTN...WHICH WILL LEAD TO A VERY MOISTURE
BOUNDARY LAYER. LATER SHIFTS WILL NEED TO EVALUATE THE EXTENT OF
THE LOWER CIGS TO THE WEST AND IF MORE CIGS DEVELOP THIS
AFTN/EVENING. ONCE THE TROUGH/FRONTAL BOUNDARY MOVES ACROSS THE
AREA LATE TONIGHT/THURSDAY MORNING...EXPECT THE CIGS TO LIFT TO
VFR WITH WNDS BECOMING MORE WNW AND GUSTY BY LATE MORNING.
MSP...VFR CIGS/VSBYS SHOULD CONT THRU 00Z...WITH SOME PROBLEMS
DEVELOPING AFT 00Z...ESPECIALLY DURING THE EVENING AS THE BOUNDARY
LAYER BECOMES VERY MOIST. BASED ON RUC TRENDS AND ANTICIPATED
MOISTURE ADV AND CIGS TO THE WEST...HAVE LOWER CIGS TO MVFR BY
2Z...AND CONTINUING THESE CIGS THRU 9Z OR AS WNDS BECOME MORE
SW/WSW. WNDS WILL LIKELY BECOME GUSTY BY LATE MORNING/AFTN FROM
THE WNW.
FRI...MVFR/IFR CIGS/VSBYS POSSIBLE IN -SN.
SAT...MVFR/IFR CIGS/VSBYS POSSIBLE IN -SN.
SUN/MON...VFR.
TUE...MVFR/IFR CIGS/VSBYS POSSIBLE. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1127 AM CST WED JAN 25 2012
.DISCUSSION...
LIGHT SNOW CONTINUES TO SPREAD NORTH AND EAST ACROSS THE CWA EARLY
THIS MORNING...AHEAD OF A SHORT WAVE OVER SOUTHWEST MN. WRF
GUIDANCE SUGGESTS THE SNOW WILL END ACROSS THE FA TOWARDS NOON.
SNOW AMOUNTS OF A HALF INCH TO ONE INCH LIKELY IN THE HIGHER DBZ
BANDING. ALTHOUGH STRONG DRYING IS INDICATED THIS AFTERNOON
ALOFT...LOW LEVEL MOISTURE REMAINS HIGH AND HELD ON TO PLENTY OF
CLOUD COVER. THIS...ALONG SOME NEW SNOW...RESULTED IN TRIMMING THE
HIGHS TODAY BY A FEW DEGREES.
PRETTY GOOD CONTINUITY REMAINS IN THE FORECAST AHEAD AGAIN
TONIGHT WITH A FLURRY OF SHORT WAVE ACTION INTO EARLY NEXT WEEK.
THE WAVE ATTRACTING THE MOST ATTENTION RIGHT NOW IS ONE ON
FRIDAY. SNOW ASSOCIATED WITH THIS FEATURE HAS MIGRATED NORTH AND
SOUTH OVER THE PAST FEW NIGHTS. IT IS NOW BACK NORTH AND ACROSS
MUCH OF SOUTHERN MN FOR FRIDAY. THE ECMWF IS VERY BULLISH ON QPF
AND SNOWFALL. IT WAS QUITE CORRECT MONDAY NIGHT ABOUT THE FORECAST
FOR THIS MORNING...SO MORE WEIGHT OF THE ECMWF WAS USED IN THE
FORECAST FOR FRIDAY. THE NEIGHBORS AGREED AND WE NOW HAVE CHANCE
POPS ALONG AND SOUTH OF THE MN RIVER. THALER QG FROM THE NAM/GFS
FAVOR THE SOUTHERN THIRD OF MN.
COLDER AIR IS STILL ON TAP FOR THE WEEKEND AND SOME LIGHT SNOW
CAN NOT BE RULED OUT ACROSS THE CWA ON SATURDAY. SOME
DISCREPANCIES DO EXIST BETWEEN THE MODELS ON MOISTURE AND TIMING...
WITH THE EASTERN CWA HAVING SOME CHANCE FOR LIGHT SNOW RIGHT NOW.
AREAL COVERAGE AND POPS MAY NEED TO BE EXPANDING WITH TIME.
THE COLD IS SHORT LIVED WITH WAA SETTING IN SUNDAY NIGHT FROM THE
WEST. AGAIN...THERE LOOKS TO BE A PRETTY GOOD CHANCE FOR SNOW
ACROSS NORTHERN MN AND WI AS THE NEXT WAVE MOVES THROUGH.
HENCE...CHANCES FOR SNOW CONTINUE IN THE GRIDS FOR SUNDAY NIGHT
AND MONDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
SEVERAL FACTORS THIS AFTN/EVENING WILL CAUSE EITHER CIGS TO
LOWER...OR REMAIN THE SAME AS THE STRONG INVERSION CONTINUES THIS
AFTN/EVENING ACROSS ALL OF THE FA.
MAIN FORECAST CONCERN DEALS WITH ONGOING MVFR/IFR/LIFR CIGS ACROSS
WESTERN MN...AND IF THEY ADV EASTWARD THIS EVENING.
BASED ON CURRENT LOW LEVEL FLOW BLW 90H...BELIEVE MOST OF THE
LOWER CIGS ACROSS THE WEST WILL REMAIN WEST THRU 00Z...OR UNTIL
THE WNDS BECOME MORE SSW/SW OVERNIGHT WHICH WILL BRING THE LOWER
CIGS ACROSS EASTERN MN/WESTERN WI. AM LEANING TOWARD A MORE
OPTIMISTIC FORECAST FOR MSP/RNH/EAU THIS AFTN...WITH LOWER CIGS
NOT MOVING INTO THIS AREA UNTIL AFT 2Z. CONFIDENCE IS LOW ON ANY
ONE SCENARIO...ESPECIALLY SINCE WE HAVE SOME MELTING OF THE SNOW
ACROSS SC MN THIS AFTN...WHICH WILL LEAD TO A VERY MOISTURE
BOUNDARY LAYER. LATER SHIFTS WILL NEED TO EVALUATE THE EXTENT OF
THE LOWER CIGS TO THE WEST AND IF MORE CIGS DEVELOP THIS
AFTN/EVENING. ONCE THE TROUGH/FRONTAL BOUNDARY MOVES ACROSS THE
AREA LATE TONIGHT/THURSDAY MORNING...EXPECT THE CIGS TO LIFT TO
VFR WITH WNDS BECOMING MORE WNW AND GUSTY BY LATE MORNING.
MSP...VFR CIGS/VSBYS SHOULD CONT THRU 00Z...WITH SOME PROBLEMS
DEVELOPING AFT 00Z...ESPECIALLY DURING THE EVENING AS THE BOUNDARY
LAYER BECOMES VERY MOIST. BASED ON RUC TRENDS AND ANTICIPATED
MOISTURE ADV AND CIGS TO THE WEST...HAVE LOWER CIGS TO MVFR BY
2Z...AND CONTINUING THESE CIGS THRU 9Z OR AS WNDS BECOME MORE
SW/WSW. WNDS WILL LIKELY BECOME GUSTY BY LATE MORNING/AFTN FROM
THE WNW.
FRI...MVFR/IFR CIGS/VSBYS POSSIBLE IN -SN.
SAT...MVFR/IFR CIGS/VSBYS POSSIBLE IN -SN.
SUN/MON...VFR.
TUE...MVFR/IFR CIGS/VSBYS POSSIBLE. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JLT
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1055 PM CST TUE JAN 24 2012
.AVIATION.../06Z TAF ISSUANCE/
-SN HAS BECOME MORE WIDESPREAD THAN EARLIER EXPECTED AHEAD OF UPPER
TROF NOW MOVING INTO E SODAK INTO NC NEB. MPX AND SURROUNDING
RADARS ALSO SHOW PCPN BLOSSOMING. SOME CONCERN OF A PERIOD SLEET OR
-FZRA AS PCPN BEGINS...BUT THIS SHOULD REMAIN SOUTH OF ANY TAF
SITES. ANY -SN AT AXN SHUD BE BEFORE 08Z. EXPCT A PERIOD OF IFR
VSBYS IN SNOW AT STC/RWF/MSP/RNH OVRNITE WITH THESE CONDS AT RWF/STC
GNRLY BFR 09Z. CIGS SHUD GNRLY LOWER TO MVFR WITHIN AN HOUR OR SO
OF BEGINNING OF -SN. SATELLITE IMAGERY SHOWING A FAIRLY EXPANSIVE
AREA OF MVFR TO IFR CIGS BEHIND THE UPPER TROF...ACROSS E AN CNTRL
SODAK INTO NEB. 925MB RN ON 00Z NAM SEEMS TO HANDLE THIS FAIRLY
WELL WHICH WOULD KEEP MVFR CIGS ACRS MUCH OF AREA WELL INTO
WEDNESDAY.
KMSP...MPX RADAR HAS BEEN SHOWING -SN BLOSSOMING ARND AREA AND
EXPECT THAT MVFR VSBYS IN -SN SHUD BEGIN NEAR 06Z TAF TIME. HAVE A
WINDOW OF VSBYS 2SM FROM 08Z-12Z. AFTER SNOW ENDS BY 13Z OR
SO...SHUD MAINTAIN MVFR CIGS INTO MID AFTN.
&&
.DISCUSSION...ISSUED 240 PM CST
OVERALL THE LARGE SCALE PATTERN IS FAIRLY BENIGN WITH RESPECT TO
ITS IMPACT ON SENSIBLE WEATHER IN OUR AREA OVER THE UPCOMING WEEK.
WEST TO NORTHWEST UPPER FLOW WILL PREDOMINATE... BRINGING PERIODIC
MOISTURE DEFICIENT SHORTWAVES THROUGH OUR AREA WHICH WILL
GENERALLY AMPLIFY ONCE THEY GET EAST OF OUR LONGITUDE.
TEMPERATURES LOOK TO BE A BIT ABOVE NORMAL FOR THE MOST PART...
WITH THE COLDEST PERIOD AND PERHAPS SOME BELOW NORMAL READINGS IN
STORE FOR SATURDAY INTO MONDAY. LATEST SATELLITE IMAGERY AND RADAR
DATA SHOW CLOUDS STREAMING IN FROM THE WEST AT THE CURRENT TIME...
AHEAD OF A SHORTWAVE TROUGH WHICH CAN BE SEEN ON WATER VAPOR
MOVING INTO THE DAKOTAS. THERE HAVE BEEN A FEW OBSERVATIONS OF
LIGHT RAIN AND SNOW AHEAD OF THIS FEATURE... ALTHOUGH MUCH OF THE
ACTIVITY IS STILL ALOFT AT THE CURRENT TIME. GIVEN THE LACK OF
GOOD MOISTURE RETURN AHEAD OF THIS FEATURE... THE 12Z GUIDANCE
FROM THE GFS AND NAM ARE UNDERSTANDABLY UNDERWHELMING IN THEIR
PRODUCTION OF PCPN AS THIS SYSTEM MOVES THROUGH THE AREA TONIGHT
INTO WEDNESDAY MORNING... ALTHOUGH ALL MANAGE TO SQUEEZE OUT A
LITTLE BIT OF PCPN GIVEN THE COMBINATION OF SOME DECENT ISENTROPIC
LIFT AND DPVA AHEAD OF THE TROUGH. THE HIGH RESOLUTION
SOLUTIONS... INCLUDING THE HRRR... ALSO SUGGEST A PERIOD OF SOME
LIGHT PCPN TONIGHT INTO MONDAY MORNING... WITH A BETTER CO-LOCATION
OF SATURATION AND FORCING OVER THE SOUTHERN PART OF THE CWFA.
RAISED POPS SOME WITH THIS SYSTEM... BUT KEPT THEM IN THE CHANCE
RANGE SINCE ALTHOUGH IT SEEMS LIKELY THAT IT WILL PRECIPITATE IT
IS STILL QUESTIONABLE AS TO WHETHER OR NOT IT WILL MEASURE.
ANOTHER SMALL CONCERN AS THE SYSTEM MOVES THOUGH TONIGHT IS
WHETHER THE ELEVATED WARM NOSE... WHICH LOOKS LIKE IT WILL BE
AROUND 900-925MB... WILL BE SUFFICIENT TO CAUSE MELTING OF
HYDROMETEORS AS THEY DESCEND TO THE SURFACE. THE NAM IS THE MOST
BULLISH IN WARMING TEMPERATURES ALOFT... WHILE THE GFS AND RUC ARE
NOT AS STRONG WITH THE WARMING. THE UPSTREAM 12Z SOUNDING AT OMAHA
DEFINITELY SHOWED AN ABOVE FREEZING LAYER... SO THE QUESTION WILL
BE WHETHER IT IS ABLE TO COOL MUCH TOWARD THE WET BULB GIVEN THE
DRYNESS IN THE LAYER... OR IF MOISTURE ADVECTION OVERWHELMS THINGS
AND WE SIMPLY SEE THE WARM NOSE SATURATE WITH LITTLE CHANGE IN
TEMPERATURE. LOOKING AT THE UPSTREAM MIXING RATIOS IN THE
SOUTHWEST-NORTHEAST ORIENTED AXIS AHEAD OF THE TROUGH... FEEL
THERE SHOULD BE A TENDENCY TO MOISTEN IN THAT LAYER QUITE A BIT...
SO THINK THERE WILL BE POTENTIAL FOR AN ABOVE FREEZING WARM LAYER
FOR A TIME TONIGHT AS THE PCPN MOVES THROUGH... PARTICULARLY ALONG
AND SOUTH OF I-90. WITH THAT IN MIND... INCLUDING A MENTION OF
SOME IP ALONG WITH SN OVER THE SOUTHERN PART OF THE AREA FOR TONIGHT.
ONCE TONIGHT/S SYSTEM GETS OUT OF OUR HAIR... THINGS LOOK TO BE
FAIR AND DRY THROUGH THURSDAY... WITH THE NEXT CHANCE FOR ANY
MEANINGFUL PCPN HOLDING OFF UNTIL FRIDAY. WARM ADVECTION WILL
INCREASE ACROSS THE AREA TOMORROW AFTERNOON INTO TOMORROW
EVENING... WITH A FRONTAL SLIDING ACROSS THE STATE TOMORROW NIGHT.
THIS FRONT IS THE ONE POTENTIAL PCPN PRODUCER PRIOR TO FRIDAY...
BUT AT THIS TIME IT LOOKS LIKE WE WILL BE HARD PRESSED TO SEE
SUFFICIENT MOISTURE WORK INTO THE AREA PRIOR TO ITS PASSAGE TO
WRING OUT ANY PCPN. IT/S POSSIBLE THAT LATER FORECASTS WILL NEED
TO INCLUDE SOME FLURRIES OVER THE NORTHERN PART OF THE CWFA FOR
TOMORROW NIGHT... BUT FOR NOW THE MOST LIKELY SCENARIO STILL LOOKS
TO BE A DRY FROPA. A BRIEF COOL DOWN IS EXPECTED THURSDAY THROUGH
THURSDAY NIGHT AS HIGH PRESSURE DROPS SOUTHEAST INTO THE CENTRAL
PLAINS AND NORTHWEST FLOW BRINGS A QUICK SHOT OF SOME MODIFIED
ARCTIC AIR INTO THE REGION. A SHORTWAVE THEN LOOKS TO SWING
THROUGH THE AREA ON FRIDAY... WITH THE ECMWF AND GFS AND
REASONABLE AGREEMENT... ALTHOUGH THE ECMWF SOLUTION IS A BIT MORE
AMPLIFIED AND THEREFORE SLOWER AND ACCOMPANIED BY MORE IN THE WAY
OF PCPN. IN EITHER CASE... THERE LOOKS TO BE ENOUGH FORCING AND
DEEP LAYER SATURATION TO SUPPORT A MENTION OF POPS. UNFORTUNATELY
THE DIFFERENCES IN TIMING AND UNCERTAINTY REQUIRE BLANKETING A
LONGER PERIOD OF TIME WITH POPS THAN WHAT WILL EVENTUALLY OCCUR IN
REALITY... SO INCLUDED SOME CHANCE POPS FOR SNOW FROM FRIDAY INTO
SATURDAY FROM WEST TO EAST ACROSS THE AREA. LATER FORECASTS SHOULD
CERTAINLY BE ABLE TO NARROW AND FOCUS THIS TEMPORAL WINDOW ONCE
THINGS COME INTO BETTER AGREEMENT.
A DECENT SLUG OF COLD AIR LOOKS TO DROP INTO THE REGION AFTER
SATURDAY/S SYSTEM MOVES BY... BUT IT WILL BE SHORT-LIVED AS THE
GFS... ECMWF... AND THEIR RESPECTIVE ENSEMBLE ALL SUPPORT THE IDEA
OF A SUBSTANTIAL RIDGE BUILDING TO OUR WEST BY THE SUNDAY-MONDAY
TIME FRAME. RETURN FLOW WILL START TO BRING IN WARMER TEMPERATURES
ASSOCIATED WITH THIS RIDGE BY THE SUNDAY NIGHT INTO MONDAY TIME
FRAME... WITH SOME PCPN POSSIBLY DEVELOPING IN THE AREA OF
ISENTROPIC ASCENT DURING THAT TIME FRAME. A SOMEWHAT UNSETTLED
PATTERN THEN LOOKS TO PERSIST INTO TUESDAY AS THE NEXT SHORTWAVE
AND ASSOCIATED COLD FRONT WORK TOWARD THE AREA. ALL OF THIS WINDS
UP LEADING TO THE INCLUSION OF SOME CHANCE POPS FOR MUCH OF THE
PERIOD FROM SUNDAY NIGHT INTO TUESDAY... PARTICULARLY OVER THE
NORTHERN AND EASTERN PART OF THE CWFA WHERE BETTER SATURATION
ALONG THE SLOPED FRONTAL ZONE IS MORE LIKELY TO TAKE PLACE. IN
ADDITION... THINGS COULD CERTAINLY WARM ENOUGH BY MONDAY NIGHT OR
TUESDAY FOR SOME PTYPE ISSUES... SO INCLUDED SOME RN/SN MENTION BY
TUESDAY TO HIGHLIGHT THAT POSSIBILITY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/BAP
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1033 AM EST WED JAN 25 2012
.SYNOPSIS...
LINGERING LIGHT SNOW SHOWERS AND FLURRIES WILL END ACROSS THE
NORTHERN MOUNTAINS LATE TODAY AS CLOUDS SLOWLY THIN OVER TIME AND
WEAK HIGH PRESSURE BUILDS INTO THE REGION. EXPECT GENERALLY FAIR
AND DRY WEATHER TONIGHT INTO THURSDAY...BEFORE MIXED PRECIPITATION
ARRIVES THURSDAY NIGHT INTO FRIDAY MORNING. TEMPERATURES WILL COOL
TO NEAR SEASONAL LATE JANUARY NORMALS TODAY INTO THURSDAY...THEN
TREND ABOVE NORMAL BY FRIDAY INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1032 AM EST WEDNESDAY...VISIBLE SATELLITE LOOP SHOWING LOW
CLOUD COVER HANGING IN ACROSS THE REGION THIS MORNING. 12Z ALBANY
RAOB SOUNDING SHOWING THIS LOW LEVEL MOISTURE IN THE 1000-850 MB
LAYER. THIS SOUNDING ALSO SHOWS A STRONG TEMPERATURE INVERSION
ABOVE THIS LAYER...SO EXPECTING CLOUD COVER TO HANG IN THROUGH THE
REMAINDER OF TODAY. HAVE LOWERED POPS FOR THE REMAINDER OF
TODAY...BUT HAVE KEPT IN A MENTION OF SNOW FLURRIES ACROSS THE
ADIRONDACKS AND THE GREEN MOUNTAINS AND NORTHEAST VERMONT. MAX
TEMPERATURES HAVE OCCURRED EARLIER TODAY...SO EXPECTING
TEMPERATURES TO REMAIN NEARLY STEADY OR FALL SLIGHT THROUGH THE
REST OF TODAY.
AS OF 628 AM EST WEDNESDAY...MINOR UPDATE TO MATCH CURRENT T/TD
OBSERVATIONAL DATA AND BLEND INTO LATEST LAMP DATA THIS AFTERNOON.
ALSO OPTED TO KEEP CLOUD COVER IN A LITTLE LONGER TODAY PER
STRONGER INVERSION EVIDENT OFF 10Z RUC SOUNDING PROGS. HIGHS
SHOULD OCCUR THIS MORNING AS MID LVL TEMPS CONTINUE TO COOL
TODAY...BUT NOT A SHARP DROP EXPECTED...JUST A GRADUAL COOL DOWN
OF 3-6 DEG OVER THE COURSE OF THE DAY IN MOST AREAS. REST OF
FORECAST UNCHANGED.
PRIOR DISCUSSION...
GENERALLY QUIET WEATHER ON TAP TODAY
UNDER MODEST WEST TO NORTHWEST FLOW ON THE BACK SIDE OF DEPARTING
UPPER TROUGH. ANY LINGERING LIGHT SHSN/FLURRIES TO END ACROSS THE
NORTHERN MOUNTAINS BY THIS AFTERNOON AS CLOUDS THIN BY LATE
AFTERNOON/EARLY EVENING AND WEAK HIGH PRESSURE BUILDS EAST.
MODEST CAA IN THE LOWER LEVELS AND ABUNDANT CLOUD COVER THROUGH
MUCH OF THE DAY SHOULD KEEP TEMPERATURES FAIRLY STEADY THROUGH
LATE AFTERNOON...GENERALLY IN THE 20S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
AS OF 215 AM EST WEDNESDAY...THEN CLEAR TO PTLY CLOUDY SKIES
THROUGH THE NIGHTTIME HOURS ALONG WITH LIGHT WINDS AS BROAD AND
ELONGATED HIGH PRESSURE FROM THE GREAT LAKES INTO THE MID
ATLANTIC REGION APPROACHES. DECENT RADIATIONAL COOLING NIGHT ON
TAP...BUT WITH GENERAL LACK OF SNOW AND/OR FRESH SNOW COVER IN
MOST AREAS ONLY NEAR SEASONAL LOWS EXPECTED IN THE 5 TO 15 DEGREE
RANGE TO NEAR 20 SOUTH.
SFC HIGH TO THEN BUILD ATOP AND EAST OF THE REGION DURING
THURSDAY AS FLOW TRENDS TO LIGHT EAST/SOUTHEASTERLY BY DAYS END.
DRY WEATHER IS EXPECTED THOUGH A BROAD INCREASE IN MID TO UPPER
LEVEL CLOUD COVER WILL OCCUR FROM THE SOUTHWEST LATER IN THE DAY
AS WAA ALOFT SPREADS NORTHEAST IN ADVANCE OF APPROACHING SOUTHERN
STREAM SHORTWAVE. 925 HPA THERMAL PROFILES FROM THIS MORNING`S
NEAR TERM GUIDANCE SUPPORTS MOS HIGHS IN THE LOWER TO MID 30S
AREA WIDE WITH CUSTOMARY ADJUSTMENTS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AS OF 330 AM EST WEDNESDAY...SOME DIFFERENCES REMAIN BETWEEN THE
GFS AND ECMWF FROM THURSDAY NIGHT ONWARD. LOW PRESSURE SYSTEM
APPROACHES FROM OHIO VALLEY REGION ON THURSDAY NIGHT...SPREADING
PRECIP ACROSS OUR FORECAST AREA FROM SOUTH TO NORTH. ECMWF IS A
BIT FASTER WITH THIS SYSTEM BY ABOUT 6 HOURS. THEN GFS KEEPS LOW
TRACKING NORTHEAST AND OFF THE COAST OF NEW ENGLAND. ECMWF BRINGS
THE SYSTEM INLAND AND CUTS THROUGH NEW ENGLAND. PLACEMENT OF LOW
WILL DETERMINE AMOUNT AND TYPE OF PRECIP...THEREFORE STILL SOME
UNCERTAINTY WITH REGARDS TO THIS PART OF THE FORECAST. AT THIS
TIME MAINLY HAVE MENTIONED SLEET AND SNOW. LOW WILL PASS EAST ON
FRIDAY AND PRECIP CHANGES OVER TO UPSLOPE SNOW SHOWERS FRIDAY
NIGHT AND ENDS BY EARLY SATURDAY MORNING. WEATHER WILL REMAIN
FAIRLY QUIET AFTER THIS SYSTEM DEPARTS...BUT WITH A SLOW MOVING
LOW PRESSURE SYSTEM TO OUR NORTH HAVE MENTION OF CHANCE SNOW
SHOWERS FROM LATE SATURDAY NIGHT THROUGH MONDAY EVENING. DRY
WEATHER THEN RETURNS THROUGH THE END OF THE PERIOD. ABOVE NORMAL
TEMPERATURES...WITH A COUPLE PERIODS NEAR NORMAL...CONTINUES
THROUGH THE EXTENDED.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...BKN/OVC MAINLY VFR CIGS EXPECTED THROUGH 18Z
UNDER MODEST AND OCCNLY GUSTY WEST/NORTHWESTERLY WINDS. EXCEPTION
WILL BE LINGERING MVFR CIGS AND PERHAPS A STRAY FLURRY AT
KSLK/KMPV THROUGH 16Z OR SO. AFTER 18Z...VFR EXPECTED AT ALL
TERMINALS UNDER SLOWLY ABATING WINDS. SOME BKN MID LEVEL CLOUD
COVER FROM FL120-200 POSSIBLE FROM 18-22Z AND ONWARD INTO THE
OVERNIGHT HOURS.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY THROUGH 00Z FRIDAY...VFR WITH WEAK HIGH PRESSURE.
BKN/OVC MID TO HIGH LVL CIGS POSSIBLE AFTER 18Z.
00Z FRIDAY THROUGH 18Z FRIDAY...MVFR/IFC IN LIGHT SNOW/MIXED PCPN
WITH LOW PRESSURE PASSING SOUTH OF REGION.
18Z FRIDAY THROUGH 12Z SUNDAY...MAINLY VFR WITH WEAK HIGH
PRESSURE.
12Z SUNDAY ONWARD...MVFR/OCCNLY IFR IN SHSN WITH FRONTAL PASSAGE.
&&
.EQUIPMENT...
AS OF 1032 AM EST WEDNESDAY...THE TEMPERATURE AND DEW POINT
SENSORS ARE OUT OF SERVICE AT THIS TIME AT THE AUTOMATED SURFACE
WEATHER OBSERVING SYSTEM (ASOS) AT MASSENA INTERNATIONAL
AIRPORT/RICHARDS FIELD (KMSS) IN MASSENA NEW YORK. PARTS ARE ON
BACK ORDER TO REPAIR THESE SENSORS. PER OUR ELECTRONICS
TECHNICIAN...THESE SENSORS MAY POTENTIALLY BE OUT OF SERVICE FOR
SEVERAL DAYS...UNTIL REPLACEMENT PARTS ARRIVE.
ALSO...ON THURSDAY...JANUARY 26TH...NOAA WEATHER RADIO STATION KIG60
...ATOP OF MOUNT MANSFIELD IN NORTHWEST VERMONT...OPERATING ON A
FREQUENCY OF 162.400 MEGAHERTZ...WILL BE PERIODICALLY OFF THE AIR
OR EXPERIENCING DEGRADATION IN AUDIO QUALITY DUE TO MAINTENANCE.
THE MAINTENANCE IS TO REPLACE AN OLD NOAA WEATHER RADIO
TRANSMITTER WITH A NEW TRANSMITTER THAT SHOULD IMPROVE BROADCAST
QUALITY FOR THOSE THAT RELY ON NOAA WEATHER RADIO FOR WEATHER
FORECASTS AND LIFE-SAVING WARNINGS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/WGH
SHORT TERM...JMG
LONG TERM...NEILES
AVIATION...JMG
EQUIPMENT...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
628 AM EST WED JAN 25 2012
.SYNOPSIS...
LINGERING LIGHT SNOW SHOWERS AND FLURRIES WILL END ACROSS THE
NORTHERN MOUNTAINS TODAY AS CLOUDS SLOWLY THIN OVER TIME AND WEAK
HIGH PRESSURE BUILDS INTO THE REGION. EXPECT GENERALLY FAIR AND
DRY WEATHER TONIGHT INTO THURSDAY...BEFORE MIXED PRECIPITATION
ARRIVES THURSDAY NIGHT INTO FRIDAY MORNING. TEMPERATURES WILL
COOL TO NEAR SEASONAL LATE JANUARY NORMALS TODAY INTO
THURSDAY...THEN TREND ABOVE NORMAL BY FRIDAY INTO THE UPCOMING
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 628 AM EST WEDNESDAY...MINOR UPDATE TO MATCH CURRENT T/TD
OBSERVATIONAL DATA AND BLEND INTO LATEST LAMP DATA THIS AFTERNOON.
ALSO OPTED TO KEEP CLOUD COVER IN A LITTLE LONGER TODAY PER
STRONGER INVERSION EVIDENT OFF 10Z RUC SOUNDING PROGS. HIGHS
SHOULD OCCUR THIS MORNING AS MID LVL TEMPS CONTINUE TO COOL
TODAY...BUT NOT A SHARP DROP EXPECTED...JUST A GRADUAL COOL DOWN
OF 3-6 DEG OVER THE COURSE OF THE DAY IN MOST AREAS. REST OF
FORECAST UNCHANGED.
PRIOR DISCUSSION...
GENERALLY QUIET WEATHER ON TAP TODAY
UNDER MODEST WEST TO NORTHWEST FLOW ON THE BACK SIDE OF DEPARTING
UPPER TROUGH. ANY LINGERING LIGHT SHSN/FLURRIES TO END ACROSS THE
NORTHERN MOUNTAINS BY THIS AFTERNOON AS CLOUDS THIN BY LATE
AFTERNOON/EARLY EVENING AND WEAK HIGH PRESSURE BUILDS EAST.
MODEST CAA IN THE LOWER LEVELS AND ABUNDANT CLOUD COVER THROUGH
MUCH OF THE DAY SHOULD KEEP TEMPERATURES FAIRLY STEADY THROUGH
LATE AFTERNOON...GENERALLY IN THE 20S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
AS OF 215 AM EST WEDNESDAY...THEN CLEAR TO PTLY CLOUDY SKIES
THROUGH THE NIGHTTIME HOURS ALONG WITH LIGHT WINDS AS BROAD AND
ELONGATED HIGH PRESSURE FROM THE GREAT LAKES INTO THE MID
ATLANTIC REGION APPROACHES. DECENT RADIATIONAL COOLING NIGHT ON
TAP...BUT WITH GENERAL LACK OF SNOW AND/OR FRESH SNOW COVER IN
MOST AREAS ONLY NEAR SEASONAL LOWS EXPECTED IN THE 5 TO 15 DEGREE
RANGE TO NEAR 20 SOUTH.
SFC HIGH TO THEN BUILD ATOP AND EAST OF THE REGION DURING
THURSDAY AS FLOW TRENDS TO LIGHT EAST/SOUTHEASTERLY BY DAYS END.
DRY WEATHER IS EXPECTED THOUGH A BROAD INCREASE IN MID TO UPPER
LEVEL CLOUD COVER WILL OCCUR FROM THE SOUTHWEST LATER IN THE DAY
AS WAA ALOFT SPREADS NORTHEAST IN ADVANCE OF APPROACHING SOUTHERN
STREAM SHORTWAVE. 925 HPA THERMAL PROFILES FROM THIS MORNING`S
NEAR TERM GUIDANCE SUPPORTS MOS HIGHS IN THE LOWER TO MID 30S
AREA WIDE WITH CUSTOMARY ADJUSTMENTS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AS OF 330 AM EST WEDNESDAY...SOME DIFFERENCES REMAIN BETWEEN THE
GFS AND ECMWF FROM THURSDAY NIGHT ONWARD. LOW PRESSURE SYSTEM
APPROACHES FROM OHIO VALLEY REGION ON THURSDAY NIGHT...SPREADING
PRECIP ACROSS OUR FORECAST AREA FROM SOUTH TO NORTH. ECMWF IS A
BIT FASTER WITH THIS SYSTEM BY ABOUT 6 HOURS. THEN GFS KEEPS LOW
TRACKING NORTHEAST AND OFF THE COAST OF NEW ENGLAND. ECMWF BRINGS
THE SYSTEM INLAND AND CUTS THROUGH NEW ENGLAND. PLACEMENT OF LOW
WILL DETERMINE AMOUNT AND TYPE OF PRECIP...THEREFORE STILL SOME
UNCERTAINTY WITH REGARDS TO THIS PART OF THE FORECAST. AT THIS
TIME MAINLY HAVE MENTIONED SLEET AND SNOW. LOW WILL PASS EAST ON
FRIDAY AND PRECIP CHANGES OVER TO UPSLOPE SNOW SHOWERS FRIDAY
NIGHT AND ENDS BY EARLY SATURDAY MORNING. WEATHER WILL REMAIN
FAIRLY QUIET AFTER THIS SYSTEM DEPARTS...BUT WITH A SLOW MOVING
LOW PRESSURE SYSTEM TO OUR NORTH HAVE MENTION OF CHANCE SNOW
SHOWERS FROM LATE SATURDAY NIGHT THROUGH MONDAY EVENING. DRY
WEATHER THEN RETURNS THROUGH THE END OF THE PERIOD. ABOVE NORMAL
TEMPERATURES...WITH A COUPLE PERIODS NEAR NORMAL...CONTINUES
THROUGH THE EXTENDED.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...BKN/OVC MAINLY VFR CIGS EXPECTED THROUGH 18Z
UNDER MODEST AND OCCNLY GUSTY WEST/NORTHWESTERLY WINDS. EXCEPTION
WILL BE LINGERING MVFR CIGS AND PERHAPS A STRAY FLURRY AT
KSLK/KMPV THROUGH 16Z OR SO. AFTER 18Z...VFR EXPECTED AT ALL
TERMINALS UNDER SLOWLY ABATING WINDS. SOME BKN MID LEVEL CLOUD
COVER FROM FL120-200 POSSIBLE FROM 18-22Z AND ONWARD INTO THE
OVERNIGHT HOURS.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY THROUGH 00Z FRIDAY...VFR WITH WEAK HIGH PRESSURE.
BKN/OVC MID TO HIGH LVL CIGS POSSIBLE AFTER 18Z.
00Z FRIDAY THROUGH 18Z FRIDAY...MVFR/IFC IN LIGHT SNOW/MIXED PCPN
WITH LOW PRESSURE PASSING SOUTH OF REGION.
18Z FRIDAY THROUGH 12Z SUNDAY...MAINLY VFR WITH WEAK HIGH
PRESSURE.
12Z SUNDAY ONWARD...MVFR/OCCNLY IFR IN SHSN WITH FRONTAL PASSAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...NEILES
AVIATION...JMG
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1044 PM EST THU JAN 26 2012
.SYNOPSIS...
A PHASED UPPER LEVEL TROUGH WILL ASSUME NEGATIVE TILT AND SWEEP AN
ATTENDING SURFACE FRONTAL ZONE THROUGH THE CAROLINAS THROUGH EARLY
FRIDAY. HIGH PRESSURE WILL FOLLOW LATER FRIDAY AND FRIDAY NIGHT. A
COUPLE OF REINFORCING...DRY COLD FRONTS WILL CROSS OUR REGION LATE
SATURDAY AND AGAIN SUNDAY NIGHT.
&&
.NEAR TERM /TODAY THROUGH FRIDAY/...
AS OF 1030 PM THURSDAY...
TONIGHT: A HIGH SHEAR AND LOW -- BUT HIGHER THAN RECENT NON-EVENTS
CAPE -- SEVERE WEATHER THREAT REMAINS FOR LATE TONIGHT INTO EARLY
FRIDAY.
AT 10 PM...A DEEPENING...SUB-1000 MB SURFACE CYCLONE WAS LOCATED
OVER CENTRAL KY...WITH A TRAILING COLD FRONT THAT STRETCHED SOUTH
SOUTHWESTWARD THROUGH CENTRAL AL. A SEPARATE FRONTAL ZONE STRETCHED
ALONG THE IMMEDIATE LEE OF THE APPALACHIANS FROM GA TO VA...WHICH IS
BEING ENHANCED BY A LONG-LIVED AND NOW SUB-SEVERE PRE-FRONTAL SQUALL
LINE THAT STRETCHED FROM THE WESTERN CAROLINAS...TO EAST-CENTRAL
GA...TO THE EASTERN GOM...WELL AHEAD OF THE PRIMARY SURFACE COLD.
MEANWHILE ALOFT...WV IMAGERY AND RAOB DATA INDICATE THE FORMER
CLOSED MID-UPPER LOW HAS OPENED OVER THE WESTERN TN VALLEY AND
BECOME EMBEDDED IN A PHASED FULL-LATITUDE UPPER TROUGH THAT SPANNED
THE LOWER 48 FROM ONTARIO TO MEXICO. THIS WAVE WILL ACCELERATE WEST
OF THE APPALACHIANS WITHIN AN OBSERVED 130 KT SOUTHWESTERLY UPPER
JET TONIGHT...WHILE A NORTHERN STREAM WAVE AND ASSOCIATED MID LEVEL
COLD POOL/CAA WILL CONTINUE TO AMPLIFY SHARPLY INTO CENTRAL MS/AL
BEFORE IT TOO ACCELERATES NORTHEASTWARD...ACROSS THE CAROLINAS EARLY
FRI. LARGE SCALE FORCING FOR ASCENT...CHARACTERIZED BY 00Z OBSERVED
MID-UPPER HEIGHT FALLS AROUND 150 METERS FROM KBNA TO KJAN...WILL
ACCORDINGLY STEADILY INCREASE EAST OF THE APPALACHIANS THROUGH THE
LATE-MORNING HOURS ON FRI. A SIGNIFICANT LOW LEVEL ACCELERATION WILL
ACCOMPANY THE STRONG MID-UPPER FORCING...AND RESULT IN THE FORECAST
DEVELOPMENT OF A 50-60 KT 925 MB JET THROUGH THE CENTRAL AND EASTERN
CAROLINAS AFTER 06Z...WHICH WILL FURTHER ENHANCE ALREADY ADEQUATE
LOW LEVEL SHEAR AND PROMOTE INCREASINGLY BREEZY CONDITIONS OVER THE
CAROLINAS. INDEED...UPSTREAM VWP DATA FROM KCAE AND KGSP INDICATE A
100 PERCENT INCREASE IN THIS LLJ...FROM 20 KTS JUST A FEW HOURS AGO
TO 40-50 KTS AT 10 PM.
SINCE LARGE-SCALE FORCING AND LOW-DEEP SHEAR WILL BE PLENTIFUL...THE
TWO WILDCARDS ARE 1) HOW THE PRE-FRONTAL SQUALL LINE MAY ALTER
VERTICAL MOTION ON THE MESOSCALE OVER OUR REGION...AND 2) HOW MUCH
(BOUNDARY LAYER-BASED) INSTABILITY MATERIALIZES - THE LATTER OF
WHICH SEEMS MORE STRAIGHTFORWARD. NAM/WRF AND RUC SOLUTIONS INDICATE
THE DEVELOPMENT OF 300-500 J/KG AFTER 4 AM...AND THIS LOOKS
REASONABLE GIVEN CURRENT SURFACE OBSERVATIONAL DATA THAT INDICATES
TEMPERATURES WILL HOLD STEADY OR RISE SLIGHTLY THROUGH THE LOWER TO
MIDDLE 60S...WITH DEWPOINTS FOLLOWING A SIMILAR TENDENCY AND ABOUT
2-4 DEGREES LOWER. THE GFS ON THE OTHER HAND IS TOO COOL AND DRY IN
THE BOUNDARY LAYER AND ACCORDINGLY DEPICTS LITTLE TO NO CAPE. HOW
THE SQUALL LINE AFFECTS THE DOWNSTREAM ENVIRONMENT REMAINS MORE
PROBLEMATIC AND MAY NOT BECOME FULLY EVIDENT UNTIL A POSSIBLE SEVERE
WEATHER EVENT IS UPON US...BUT THE MAGNITUDE OF APPROACHING
LARGER-SCALE FORCING MAY RENDER ANY PRECEDING MESOSCALE EFFECTS
MOOT.
WE ACCORDINGLY EXPECT AN UPSWING IN CONVECTIVE INTENSITY LATE
TONIGHT...PERHAPS IN TWO ROUNDS WITH FIRST THE PRE-FRONTAL SQUALL
LINE...FOLLOWED BY PROBABLY STRONGER DEVELOPMENT UPSTREAM OVER AL/GA
THAT IS FOCUSED BENEATH THE MORE CONCENTRATED FORCING AND CAA ALOFT.
THE COMBINATION OF SHEAR (AND SOUTHWESTERLY DEEP SHEAR VECTORS) AND
ALBEIT WEAK INSTABILITY WILL SUPPORT A CONDITIONAL PROBABILITY OF A
FEW LOW-TOPPED SUPERCELLS AND BOWS WITH AN ATTENDING THREAT OF
DAMAGING WINDS AND ISOLATED TORNADOES...MAINLY BETWEEN 4 AND 10 AM.
WHILE THIS THREAT WILL EXIST ACROSS ALL OF CENTRAL NC...THERE MAY BE
A RELATIVE MAXIMUM TORNADIC THREAT OVER THE FOOTHILLS AND WESTERN
PIEDMONT...INVOF THE AFOREMENTIONED LEE OF THE APPALACHIANS FRONTAL
ZONE. INTERESTINGLY...RECENT HRRR RUNS INDICATE VERY LITTLE UPSTREAM
DEVELOPMENT...AND INSTEAD A RE-INVIGORATION OF THE PRE-FRONTAL
CONVECTION OVER THE EASTERN TWO THIRDS OF THE CWFA. -MWS
FRI AFTERNOON AND EVENING: THE 12Z RUN ALSO SHOWS SOME POTENTIAL FOR
A LINE OF SHORT-LIVED LIGHT SHOWERS TO DEVELOP IN THE EARLY EVENING
HOURS. WINDS ARE EXPECTED TO BE SUSTAINED AT 15-20 KTS...GUSTING TO
BETWEEN 25 AND 30 KTS. HIGHS TOMORROW ARE EXPECTED TO BE IN THE LOW
60S ACROSS THE NORTHWEST TO NEAR 70 IN THE SOUTHEAST. -KMC
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM THURSDAY...
MODIFIED SOUTHERN STREAM SFC HIGH OVER THE GULF COAST STATES WILL
BRIEFLY BUILD INTO THE AREA FRIDAY NIGHT THROUGH EARLY SATURDAY.
A PAIR OF MOISTURE-DEPRIVED CLIPPER LIKE DISTURBANCES WILL THEN
DRIVE A SERIES OF DRY COLD FRONTAL PASSAGES SOUTHEASTWARD THROUGH
THE AREA LATE SATURDAY AFTERNOON AND THEN AGAIN SUNDAY
AFTERNOON/EVENING. EACH PASSING FRONT WILL BRING MARGINALLY COOLER
AIR INTO THE REGION.
THUS..EXPECT ANOTHER MILD DAY ON SATURDAY FEATURING HIGHS IN THE
UPPER 50S TO LOWER 60S...WITH HIGHS TEMPERATURES BRIEFLY FALLING
BACK TO MORE SEASONABLE READINGS OF UPPER 40S TO LOWER 50S SUNDAY
AND MONDAY. LOWS FRIDAY NIGHT IN THE MID TO UPPER 30S...WITH NEAR
FREEZING MINS SATURDAY NIGHT AND NEAR 30 READINGS SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM WEDNESDAY...
UNSEASONABLY MILD TEMPERATURES TO CONTINUE NEXT WEEK.
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT THAT THE LARGE SCALE FLOW
OVER THE CONUS WILL QUICKLY FLATTEN/ZONAL OUT TO START THE WORK WEEK
WITH TEMPERATURES MODERATING AS SURFACE HIGH SHIFTS OFF THE
SOUTHEAST COAST. THE RESULTANT SOUTHERLY RETURN FLOW WILL MAKE 60
DEGREE READINGS PAR FOR THE COURSE BY WEDNESDAY WITH MIN
TEMPERATURES ONLY GETTING DOWN INTO THE 40S.
THERE REMAINS LITTLE RUN-TO-RUN CONSISTENCY WRT TO THE
DEVELOPMENT/AMPLITUDE OF A LOW AMPLITUDE SHORTWAVE TROUGH BY THE MID
TO LATE WEEK TIME FRAME. GIVEN THE ZONAL FLOW ALOFT THERE REMAINS
QUESTIONS IF THERE WILL BE ENOUGH MOISTURE TRANSPORT...AND THUS WILL
CARRY ONLY A SLIGHT CHANCE POP FOR NOW.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 740 PM THURSDAY...
24-HR TAF PERIOD:
A STRONG COLD FRONT WILL APPROACH THE AREA THIS EVENING AND CROSS
CENTRAL NC FRIDAY MORNING. EXPECT WINDS TO INCREASE OUT OF THE SOUTH
TO SOUTHWEST LATER THIS EVENING INTO THE EARLY MORNING HOURS OF
FRIDAY... WITH SUSTAINED WINDS OF AROUND 15 TO 20 MPH... WITH GUSTS
AS HIGH AS 30 TO 35 MPH. IF WINDS DO NOT INCREASE OVER THE NEXT
SEVERAL HOURS... A SMALL WINDOW FOR LLWS WILL BE POSSIBLE AS WINDS
JUST OFF THE SURFACE STRENGTHEN WITH THE APPROACHING SYSTEM.
HOWEVER... THINK THIS THREAT SHOULD BE SHORT LIVED AS WINDS WILL
INCREASE AFTER MIDNIGHT AT LEAST AS THE MSLP GRADIENT TIGHTENS. A
BROKEN BAND OF SHOWERS AND ISOLATED STORMS ARE EXPECTED ALONG AND
AHEAD OF THE FRONT AS WELL... WITH STRONG GUSTY WINDS POSSIBLE WITH
ANY STRONG SHOWERS OR STORMS. EXPECT THE BEST CHANCE FOR SHOWERS AND
STORMS WILL BE FROM MIDNIGHT IN THE WEST TO MID MORNING IN THE EAST.
IN ADDITION TO THREAT OF PRECIP... EXPECT CIGS AND VISBYS WILL
GENERALLY DROP INTO THE MVFR/IFR RANGE AS THE FRONT APPROACHES AND
PRECIP MOVES INTO THE AREA... WITH POSSIBLY SOME MVFR VISBYS AND
CIGS THIS EVENING ALONG WITH SOME ISOLATED SHOWERS.
EXPECT THE FRONT AND ANY LINGERING PRECIP TO BE TO THE EAST OF THE
AREA BY FRIDAY AFTERNOON... WITH A RETURN TO VFR CONDITIONS.
HOWEVER... GUSTY WNW TO NW WINDS WILL FOLLOW THE FRONT... WITH
SUSTAIN WIND IN THE 15 TO 20 MPH RANGE... WITH GUSTS OF UP TO 25 TO
30 MPH.
LOOKING AHEAD:
WINDS WILL QUICKLY WEAKEN AND BECOME LIGHT/VARIABLE BY OR SHORTLY
AFTER SUNSET FRIDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM
THE WEST. THERE IS RELATIVELY HIGH CONFIDENCE THAT DRY/VFR
CONDITIONS WILL RULE FRIDAY NIGHT THROUGH EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/KC
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 PM EST THU JAN 26 2012
.SYNOPSIS...
A PHASED UPPER LEVEL TROUGH WILL ASSUME NEGATIVE TILT AND SWEEP AN
ATTENDING SURFACE FRONTAL ZONE THROUGH THE CAROLINAS THROUGH EARLY
FRIDAY. HIGH PRESSURE WILL FOLLOW LATER FRIDAY AND FRIDAY NIGHT. A
COUPLE OF REINFORCING...DRY COLD FRONTS WILL CROSS OUR REGION LATE
SATURDAY AND AGAIN SUNDAY NIGHT.
&&
.NEAR TERM /TODAY THROUGH FRIDAY/...
AS OF 1030 PM THURSDAY...
TONIGHT: A HIGH SHEAR AND LOW -- BUT HIGHER THAN RECENT NON-EVENTS
CAPE -- SEVERE WEATHER THREAT REMAINS FOR LATE TONIGHT INTO EARLY
FRIDAY.
AT 10 PM...A DEEPENING...SUB-1000 MB SURFACE CYCLONE WAS LOCATED
OVER CENTRAL KY...WITH A TRAILING COLD FRONT THAT STRETCHED SOUTH
SOUTHWESTWARD THROUGH CENTRAL AL. A SEPARATE FRONTAL ZONE STRETCHED
ALONG THE IMMEDIATE LEE OF THE APPALACHIANS FROM GA TO VA...WHICH IS
BEING ENHANCED BY A LONG-LIVED AND NOW SUB-SEVERE PRE-FRONTAL SQUALL
LINE THAT STRETCHED FROM THE WESTERN CAROLINAS...TO EAST-CENTRAL
GA...TO THE EASTERN GOM...WELL AHEAD OF THE PRIMARY SURFACE COLD.
MEANWHILE ALOFT...WV IMAGERY AND RAOB DATA INDICATE THE FORMER
CLOSED MID-UPPER LOW HAS OPENED OVER THE WESTERN TN VALLEY AND
BECOME EMBEDDED IN A PHASED FULL-LATITUDE UPPER TROUGH THAT SPANNED
THE LOWER 48 FROM ONTARIO TO MEXICO. THIS WAVE WILL ACCELERATE WEST
OF THE APPALACHIANS WITHIN AN OBSERVED 130 KT SOUTHWESTERLY UPPER
JET TONIGHT...WHILE A NORTHERN STREAM WAVE AND ASSOCIATED MID LEVEL
COLD POOL/CAA WILL CONTINUE TO AMPLIFY SHARPLY INTO CENTRAL MS/AL
BEFORE IT TOO ACCELERATES NORTHEASTWARD...ACROSS THE CAROLINAS EARLY
FRI. LARGE SCALE FORCING FOR ASCENT...CHARACTERIZED BY 00Z OBSERVED
MID-UPPER HEIGHT FALLS AROUND 150 METERS FROM KBNA TO KJAN...WILL
ACCORDINGLY STEADILY INCREASE EAST OF THE APPALACHIANS THROUGH THE
LATE-MORNING HOURS ON FRI. A SIGNIFICANT LOW LEVEL ACCELERATION WILL
ACCOMPANY THE STRONG MID-UPPER FORCING...AND RESULT IN THE FORECAST
DEVELOPMENT OF A 50-60 KT 925 MB JET THROUGH THE CENTRAL AND EASTERN
CAROLINAS AFTER 06Z...WHICH WILL FURTHER ENHANCE ALREADY ADEQUATE
LOW LEVEL SHEAR AND PROMOTE INCREASINGLY BREEZY CONDITIONS OVER THE
CAROLINAS. INDEED...UPSTREAM VWP DATA FROM KCAE AND KGSP INDICATE A
100 PERCENT INCREASE IN THIS LLJ...FROM 20 KTS JUST A FEW HOURS AGO
TO 40-50 KTS AT 10 PM.
SINCE LARGE-SCALE FORCING AND LOW-DEEP SHEAR WILL BE PLENTIFUL...THE
TWO WILDCARDS ARE 1) HOW THE PRE-FRONTAL SQUALL LINE MAY ALTER
VERTICAL MOTION ON THE MESOSCALE OVER OUR REGION...AND 2) HOW MUCH
(BOUNDARY LAYER-BASED) INSTABILITY MATERIALIZES - THE LATTER OF
WHICH SEEMS MORE STRAIGHTFORWARD. NAM/WRF AND RUC SOLUTIONS INDICATE
THE DEVELOPMENT OF 300-500 J/KG AFTER 4 AM...AND THIS LOOKS
REASONABLE GIVEN CURRENT SURFACE OBSERVATIONAL DATA THAT INDICATES
TEMPERATURES WILL HOLD STEADY OR RISE SLIGHTLY THROUGH THE LOWER TO
MIDDLE 60S...WITH DEWPOINTS FOLLOWING A SIMILAR TENDENCY AND ABOUT
2-4 DEGREES LOWER. THE GFS ON THE OTHER HAND IS TOO COOL AND DRY IN
THE BOUNDARY LAYER AND ACCORDINGLY DEPICTS LITTLE TO NO CAPE. HOW
THE SQUALL LINE AFFECTS THE DOWNSTREAM ENVIRONMENT REMAINS MORE
PROBLEMATIC AND MAY NOT BECOME FULLY EVIDENT UNTIL A POSSIBLE SEVERE
WEATHER EVENT IS UPON US...BUT THE MAGNITUDE OF APPROACHING
LARGER-SCALE FORCING MAY RENDER ANY PRECEDING MESOSCALE EFFECTS
MOOT.
WE ACCORDINGLY EXPECT AN UPSWING IN CONVECTIVE INTENSITY LATE
TONIGHT...PERHAPS IN TWO ROUNDS WITH FIRST THE PRE-FRONTAL SQUALL
LINE...FOLLOWED BY PROBABLY STRONGER DEVELOPMENT UPSTREAM OVER AL/GA
THAT IS FOCUSED BENEATH THE MORE CONCENTRATED FORCING AND CAA ALOFT.
THE COMBINATION OF SHEAR (AND SOUTHWESTERLY DEEP SHEAR VECTORS) AND
ALBEIT WEAK INSTABILITY WILL SUPPORT A CONDITIONAL PROBABILITY OF A
FEW LOW-TOPPED SUPERCELLS AND BOWS WITH AN ATTENDING THREAT OF
DAMAGING WINDS AND ISOLATED TORNADOES...MAINLY BETWEEN 4 AND 10 AM.
WHILE THIS THREAT WILL EXIST ACROSS ALL OF CENTRAL NC...THERE MAY BE
A RELATIVE MAXIMUM TORNADIC THREAT OVER THE FOOTHILLS AND WESTERN
PIEDMONT...INVOF THE AFOREMENTIONED LEE OF THE APPALACHIANS FRONTAL
ZONE. -MWS
FRI AFTERNOON AND EVENING: THE 12Z RUN ALSO SHOWS SOME POTENTIAL FOR
A LINE OF SHORT-LIVED LIGHT SHOWERS TO DEVELOP IN THE EARLY EVENING
HOURS. WINDS ARE EXPECTED TO BE SUSTAINED AT 15-20 KTS...GUSTING TO
BETWEEN 25 AND 30 KTS. HIGHS TOMORROW ARE EXPECTED TO BE IN THE LOW
60S ACROSS THE NORTHWEST TO NEAR 70 IN THE SOUTHEAST. -KMC
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM THURSDAY...
MODIFIED SOUTHERN STREAM SFC HIGH OVER THE GULF COAST STATES WILL
BRIEFLY BUILD INTO THE AREA FRIDAY NIGHT THROUGH EARLY SATURDAY.
A PAIR OF MOISTURE-DEPRIVED CLIPPER LIKE DISTURBANCES WILL THEN
DRIVE A SERIES OF DRY COLD FRONTAL PASSAGES SOUTHEASTWARD THROUGH
THE AREA LATE SATURDAY AFTERNOON AND THEN AGAIN SUNDAY
AFTERNOON/EVENING. EACH PASSING FRONT WILL BRING MARGINALLY COOLER
AIR INTO THE REGION.
THUS..EXPECT ANOTHER MILD DAY ON SATURDAY FEATURING HIGHS IN THE
UPPER 50S TO LOWER 60S...WITH HIGHS TEMPERATURES BRIEFLY FALLING
BACK TO MORE SEASONABLE READINGS OF UPPER 40S TO LOWER 50S SUNDAY
AND MONDAY. LOWS FRIDAY NIGHT IN THE MID TO UPPER 30S...WITH NEAR
FREEZING MINS SATURDAY NIGHT AND NEAR 30 READINGS SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM WEDNESDAY...
UNSEASONABLY MILD TEMPERATURES TO CONTINUE NEXT WEEK.
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT THAT THE LARGE SCALE FLOW
OVER THE CONUS WILL QUICKLY FLATTEN/ZONAL OUT TO START THE WORK WEEK
WITH TEMPERATURES MODERATING AS SURFACE HIGH SHIFTS OFF THE
SOUTHEAST COAST. THE RESULTANT SOUTHERLY RETURN FLOW WILL MAKE 60
DEGREE READINGS PAR FOR THE COURSE BY WEDNESDAY WITH MIN
TEMPERATURES ONLY GETTING DOWN INTO THE 40S.
THERE REMAINS LITTLE RUN-TO-RUN CONSISTENCY WRT TO THE
DEVELOPMENT/AMPLITUDE OF A LOW AMPLITUDE SHORTWAVE TROUGH BY THE MID
TO LATE WEEK TIME FRAME. GIVEN THE ZONAL FLOW ALOFT THERE REMAINS
QUESTIONS IF THERE WILL BE ENOUGH MOISTURE TRANSPORT...AND THUS WILL
CARRY ONLY A SLIGHT CHANCE POP FOR NOW.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 740 PM THURSDAY...
24-HR TAF PERIOD:
A STRONG COLD FRONT WILL APPROACH THE AREA THIS EVENING AND CROSS
CENTRAL NC FRIDAY MORNING. EXPECT WINDS TO INCREASE OUT OF THE SOUTH
TO SOUTHWEST LATER THIS EVENING INTO THE EARLY MORNING HOURS OF
FRIDAY... WITH SUSTAINED WINDS OF AROUND 15 TO 20 MPH... WITH GUSTS
AS HIGH AS 30 TO 35 MPH. IF WINDS DO NOT INCREASE OVER THE NEXT
SEVERAL HOURS... A SMALL WINDOW FOR LLWS WILL BE POSSIBLE AS WINDS
JUST OFF THE SURFACE STRENGTHEN WITH THE APPROACHING SYSTEM.
HOWEVER... THINK THIS THREAT SHOULD BE SHORT LIVED AS WINDS WILL
INCREASE AFTER MIDNIGHT AT LEAST AS THE MSLP GRADIENT TIGHTENS. A
BROKEN BAND OF SHOWERS AND ISOLATED STORMS ARE EXPECTED ALONG AND
AHEAD OF THE FRONT AS WELL... WITH STRONG GUSTY WINDS POSSIBLE WITH
ANY STRONG SHOWERS OR STORMS. EXPECT THE BEST CHANCE FOR SHOWERS AND
STORMS WILL BE FROM MIDNIGHT IN THE WEST TO MID MORNING IN THE EAST.
IN ADDITION TO THREAT OF PRECIP... EXPECT CIGS AND VISBYS WILL
GENERALLY DROP INTO THE MVFR/IFR RANGE AS THE FRONT APPROACHES AND
PRECIP MOVES INTO THE AREA... WITH POSSIBLY SOME MVFR VISBYS AND
CIGS THIS EVENING ALONG WITH SOME ISOLATED SHOWERS.
EXPECT THE FRONT AND ANY LINGERING PRECIP TO BE TO THE EAST OF THE
AREA BY FRIDAY AFTERNOON... WITH A RETURN TO VFR CONDITIONS.
HOWEVER... GUSTY WNW TO NW WINDS WILL FOLLOW THE FRONT... WITH
SUSTAIN WIND IN THE 15 TO 20 MPH RANGE... WITH GUSTS OF UP TO 25 TO
30 MPH.
LOOKING AHEAD:
WINDS WILL QUICKLY WEAKEN AND BECOME LIGHT/VARIABLE BY OR SHORTLY
AFTER SUNSET FRIDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM
THE WEST. THERE IS RELATIVELY HIGH CONFIDENCE THAT DRY/VFR
CONDITIONS WILL RULE FRIDAY NIGHT THROUGH EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/KC
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1252 PM EST WED JAN 25 2012
.SYNOPSIS...
A COLD FRONT AND LOW PRESSURE WILL APPROACH THE CAROLINAS FROM THE
WEST ON THURSDAY AND PUSH EAST OF THE AREA ON FRIDAY. WEAK HIGH
PRESSURE WILL BUILD IN OVER THE WEEKEND. ANOTHER FRONT WILL BRING
MUCH COOLER AIR TO THE REGION FOR THE FIRST PART OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1245 PM WEDNESDAY... EARLY AFTERNOON UPDATE CONTINUES TRANQUIL
WEATHER FOR THIS AFTERNOON AND TREND OF MORE CLOUDS TONIGHT WITH
INCREASING CHANCE OF SHOWERS IN THE WEST TONIGHT AND ACROSS THE AREA
THURSDAY.
AT 930 AM WEDNESDAY... CLOUDS AND FOG THAT AFFECTED SOUTHERN EDGE OF
CWA EARLIER HAVE JUST ABOUT DISSIPATED. OTHERWISE... THE DAY WILL
CONTINUE AS ADVERTISED IN EARLIER DISCUSSION. THERE WILL BE QUITE A
BIT OF SUNSHINE... BUT THE GRADUAL INCREASE IN CLOUDS WILL OCCUR AS
MOISTURE SPREADS NORTHWARD AND EASTWARD FROM LOW IN THE TX/LA AREA.
AS OF 635 AM WEDNESDAY...AN AREA OF LOW CLOUDS AND FOG CONTINUE TO
SKIRT THE SE PERIPHERY OF THE FORECAST AREA THIS MORNING. HOPEFULLY
IT WILL CONTINUE MOVING SE...BUT THE RUC BNDRY LAYER RH/S IMPLY THAT
IT COULD SPREAD A LITTLE FATHER WEST. WE/LL KEEP AN EYE ON IT.
AS OF 355 AM WEDNESDAY...THE AREA OF DENSE FOG AND LOW CLOUDS HAS
INDEED BEEN PUSHING SLOWLY SOUTHWARD ACROSS THE FA. ACTUALLY...THE
GRIDS HAVE DONE A PRETTY GOOD JOB CAPTURING THIS TREND...AT LEAST
BASED ON WHAT I CAN DISCERN ON THE FOG PRODUCT. THE REST OF THE NEAR
TERM LOOKS GOOD AND ONLY A FEW TWEAKS WERE MADE.
PREVIOUS DISCUSSION...
A BACK DOOR COLD FRONT WILL PUSH ACROSS THE FA EARLY THIS MORNING.
JUST ALONG AND AHEAD OF THE FRONT...AREAS OF FOG AND STRATUS HAVE
DEVELOPED OVER THE SRN NC PIEDMONT AND OVER THE NW PIEDMONT OF SOUTH
CAROLINA. HOWEVER...BUFKIT SOUNDINGS IMPLY THAT DRIER AIR SHOULD MIX
OUT THE FOG AND STRATUS OVER THE NC PIEDMONT IN SHORT ORDER...AND
PUSH IT GRADUALLY SOUTHWARD OVER THE ERN SC UPSTATE. I DON/T THINK
ANY LOW CLOUDS WILL LAST PAST ABOUT 6 AM...AND THEY MAY EVEN MIX OUT
BEFORE THAT. OTHERWISE HIGH CLOUDS WILL GRADUALLY THICKEN AND LOWER
DURING THE COURSE OF THE DAY AS AN UPPER LOW BEGINS TO LIFT OUT
ACROSS THE SRN PLAINS. THERE IS A WELL DEFINED WARM FRONTAL BNDRY
DOWN ALONG THE GULF COAST...AND AS THIS STARTS TO LIFT NORTH IN
RESPONSE TO THE APPROACHING TROUGH...LOW CLOUDS SHOULD SPREAD ACROSS
THE FA LATER TONIGHT. PATCHY AREAS OF RAIN SHOULD ALSO BEGIN TO
DEVELOP...PARTICULARLY ALONG THE SRN AND ERN SLOPES OF THE BLUE
RIDGE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 AM WEDNESDAY...LOW LEVEL FLOW WILL CONTINUE TO INCREASE
DURING THE DAY THURSDAY...RESULTING IN GRADUAL INCREASE OF MOISTURE
LEVELS...AS WELL AS IN INCREASE IN ISENTROPIC UPGLIDE AND ESPECIALLY
MECHANICAL/UPSLOPE-INDUCED LIFT. THIS WILL RESULT IN GRADUAL
INCREASE IN POPS THROUGHOUT THE DAY...WITH LIKELY POPS ACROSS THE
SOUTHWEST NC MTNS BY AFTERNOON...EXPANDING TO THE REMAINDER OF THE
NC MTNS BY 00Z FRIDAY...AS DEEP MOISTURE PUSHES INTO THE REGION IN
ADVANCE OF FRONTAL ZONE. THE VERY MOIST FRONTAL ZONE WILL SWEEP
ACROSS THE AREA THURSDAY NIGHT...WARRANTING CATEGORICAL POPS IN ALL
AREAS BY 12Z FRIDAY. PROGGED CAPE VALUES ARE VERY LOW...BUT NON-ZERO
THROUGHOUT THE EVENT...ENOUGH TO WARRANT A SLIGHT CHANCE THUNDER
MENTION IN SOME AREAS. CONSIDERING THE VERY STRONG DEEP-LAYER
SHEAR...A LOW-END SEVERE WEATHER THREAT WILL EXIST...WITH THE
POSSIBILITY OF A DISCRETE CELL OR TWO AHEAD OF THE FRONT THURSDAY
AFTERNOON/EVENING...THEN WITH A POTENTIAL SHALLOW QLCS ALONG THE
FRONT THURSDAY NIGHT.
WEAK LOW PRESSURE DEVELOPING THE FRONT TO OUR SOUTHWEST IS EXPECTED
TO RESULT IN THE BOUNDARY SLOWING DOWN A BIT AS IT PUSHES EAST OF
THE REGION EARLY FRIDAY...SO POPS WILL BE RETAINED ACROSS THE
EASTERN AND SOUTHERN ZONES DURING THE MORNING. OTHERWISE...STRONG
COLD ADVECTION WILL RESULT IN TEMPS FALLING THROUGH THE DAY ACROSS
THE MTNS. NEVERTHELESS...THE POST-FRONTAL AIR MASS IS STILL OF
PACIFIC ORIGINS...SO TEMPS THROUGH THE REMAINDER OF THE SHORT TERM
WILL REMAIN A LITTLE ABOVE NORMAL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 235 AM WEDNESDAY...THE MEDIUM RANGE BEGINS WITH A VERY BROAD
TROUGH OVER THE EASTERN HALF OF THE COUNTRY. HOWEVER...A STRONG
SHORT WAVE TROUGH DIVING OUT OF THE UPPER MIDWEST SATURDAY NIGHT
WILL SHARPEN THE LONG WAVE PATTERN...BRINGING A COLD FRONT WILL
SIGNIFICANTLY COLDER AIR INTO THE AREA ON SUNDAY. WITH WEAK RIDGING
DOMINATING THE LOW LEVELS ACROSS THE REGION...MOISTURE WILL BE NON
EXISTENT AHEAD OF THIS FRONT...BUT SMALL POPS WILL BE CARRIED ALONG
THE TENN BORDER FOR NW FLOW MOISTURE BEHIND THE FRONT. THE MOST
OBVIOUS IMPACT OF THE FRONT WILL BE TO BRING TEMPERATURES BELOW
CLIMO FOR A COUPLE OF DAYS.
THE LATTER HALF OF THE EXTENDED WILL SEE MODERATING TEMPS...AS THE
EASTERN TROUGH PROGRESSES QUICKLY OFF THE EAST COAST...LEAVING
BEHIND A LOW AMPLITUDE/QUASI-ZONAL FLOW REGIME ACROSS MUCH OF THE
CONUS THROUGH MID-WEEK. THE WEATHER SHOULD ALSO BE DRY FOR A
CHANGE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...CEILING UNLIMITED AND VISIBILITY UNRESTRICTED. VARIABLE
WIND LESS THAN 5 KT WILL FAVOR A SOUTHEAST DIRECTION. AFTER 00Z
BROKEN CEILING NEAR 12K FT LOWERING TO NEAR 4K FT AFTER 06Z AND TO
NEAR 15 HND FT BY 12Z. VISIBILITY NEAR 6 MILES IN HAZE AND FOG
AROUND 12Z.
ELSEWHERE...SCATTERED TO BROKEN MID CLOUDS THIS EVENING WILL LOWER
FROM WEST TO EAST REACHING HEIGHTS 3K TO 5K FT BY 06Z. VISIBILITY
UNRESTRICTED EXCEPT 3 TO 5 MILES IN FOG AND HAZE AROUND 10Z AND RAIN
SHOWERS VICINITY KAVL...KAND...KGSP... AND KGMU BEFORE END OF PERIOD.
OUTLOOK... CONDITIONS SHOULD IMPROVE DURING THE DAY ON
FRIDAY...THOUGH THERE IS A CHANCE THAT CONDITIONS WON/T IMPROVE
UNTIL FRIDAY NIGHT. VFR IS THEN EXPECTED SAT AND SUN.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LGL
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
935 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH TODAY. A COLD FRONT AND
LOW PRESSURE WILL APPROACH THE CAROLINAS FROM THE WEST ON THURSDAY
AND PUSH EAST OF THE AREA ON FRIDAY. WEAK HIGH PRESSURE WILL BUILD
IN FROM THE WEST FRIDAY AND SATURDAY...BEFORE ANOTHER FRONT BRINGS
MUCH COOLER AIR TO THE REGION SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 930 AM WEDNESDAY... CLOUDS AND FOG THAT AFFECTED SOUTHERN EDGE OF
CWA EARLIER HAVE JUST ABOUT DISSIPATED. OTHERWISE... THE DAY WILL
CONTINUE AS ADVERTISED IN EARLIER DISCUSSION. THERE WILL BE QUITE A
BIT OF SUNSHINE... BUT THE GRADUAL INCREASE IN CLOUDS WILL OCCUR AS
MOISTURE SPREADS NORTHWARD AND EASTWARD FROM LOW IN THE TX/LA AREA.
AS OF 635 AM WEDNESDAY...AN AREA OF LOW CLOUDS AND FOG CONTINUE TO
SKIRT THE SE PERIPHERY OF THE FORECAST AREA THIS MORNING. HOPEFULLY
IT WILL CONTINUE MOVING SE...BUT THE RUC BNDRY LAYER RH/S IMPLY THAT
IT COULD SPREAD A LITTLE FATHER WEST. WE/LL KEEP AN EYE ON IT.
AS OF 355 AM WEDNESDAY...THE AREA OF DENSE FOG AND LOW CLOUDS HAS
INDEED BEEN PUSHING SLOWLY SOUTHWARD ACROSS THE FA. ACTUALLY...THE
GRIDS HAVE DONE A PRETTY GOOD JOB CAPTURING THIS TREND...AT LEAST
BASED ON WHAT I CAN DISCERN ON THE FOG PRODUCT. THE REST OF THE NEAR
TERM LOOKS GOOD AND ONLY A FEW TWEAKS WERE MADE.
PREVIOUS DISCUSSION...
A BACK DOOR COLD FRONT WILL PUSH ACROSS THE FA EARLY THIS MORNING.
JUST ALONG AND AHEAD OF THE FRONT...AREAS OF FOG AND STRATUS HAVE
DEVELOPED OVER THE SRN NC PIEDMONT AND OVER THE NW PIEDMONT OF SOUTH
CAROLINA. HOWEVER...BUFKIT SOUNDINGS IMPLY THAT DRIER AIR SHOULD MIX
OUT THE FOG AND STRATUS OVER THE NC PIEDMONT IN SHORT ORDER...AND
PUSH IT GRADUALLY SOUTHWARD OVER THE ERN SC UPSTATE. I DON/T THINK
ANY LOW CLOUDS WILL LAST PAST ABOUT 6 AM...AND THEY MAY EVEN MIX OUT
BEFORE THAT. OTHERWISE HIGH CLOUDS WILL GRADUALLY THICKEN AND LOWER
DURING THE COURSE OF THE DAY AS AN UPPER LOW BEGINS TO LIFT OUT
ACROSS THE SRN PLAINS. THERE IS A WELL DEFINED WARM FRONTAL BNDRY
DOWN ALONG THE GULF COAST...AND AS THIS STARTS TO LIFT NORTH IN
RESPONSE TO THE APPROACHING TROUGH...LOW CLOUDS SHOULD SPREAD ACROSS
THE FA LATER TONIGHT. PATCHY AREAS OF RAIN SHOULD ALSO BEGIN TO
DEVELOP...PARTICULARLY ALONG THE SRN AND ERN SLOPES OF THE BLUE
RIDGE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 AM WEDNESDAY...LOW LEVEL FLOW WILL CONTINUE TO INCREASE
DURING THE DAY THURSDAY...RESULTING IN GRADUAL INCREASE OF MOISTURE
LEVELS...AS WELL AS IN INCREASE IN ISENTROPIC UPGLIDE AND ESPECIALLY
MECHANICAL/UPSLOPE-INDUCED LIFT. THIS WILL RESULT IN GRADUAL
INCREASE IN POPS THROUGHOUT THE DAY...WITH LIKELY POPS ACROSS THE
SOUTHWEST NC MTNS BY AFTERNOON...EXPANDING TO THE REMAINDER OF THE
NC MTNS BY 00Z FRIDAY...AS DEEP MOISTURE PUSHES INTO THE REGION IN
ADVANCE OF FRONTAL ZONE. THE VERY MOIST FRONTAL ZONE WILL SWEEP
ACROSS THE AREA THURSDAY NIGHT...WARRANTING CATEGORICAL POPS IN ALL
AREAS BY 12Z FRIDAY. PROGGED CAPE VALUES ARE VERY LOW...BUT NON-ZERO
THROUGHOUT THE EVENT...ENOUGH TO WARRANT A SLIGHT CHANCE THUNDER
MENTION IN SOME AREAS. CONSIDERING THE VERY STRONG DEEP-LAYER
SHEAR...A LOW-END SEVERE WEATHER THREAT WILL EXIST...WITH THE
POSSIBILITY OF A DISCRETE CELL OR TWO AHEAD OF THE FRONT THURSDAY
AFTERNOON/EVENING...THEN WITH A POTENTIAL SHALLOW QLCS ALONG THE
FRONT THURSDAY NIGHT.
WEAK LOW PRESSURE DEVELOPING THE FRONT TO OUR SOUTHWEST IS EXPECTED
TO RESULT IN THE BOUNDARY SLOWING DOWN A BIT AS IT PUSHES EAST OF
THE REGION EARLY FRIDAY...SO POPS WILL BE RETAINED ACROSS THE
EASTERN AND SOUTHERN ZONES DURING THE MORNING. OTHERWISE...STRONG
COLD ADVECTION WILL RESULT IN TEMPS FALLING THROUGH THE DAY ACROSS
THE MTNS. NEVERTHELESS...THE POST-FRONTAL AIR MASS IS STILL OF
PACIFIC ORIGINS...SO TEMPS THROUGH THE REMAINDER OF THE SHORT TERM
WILL REMAIN A LITTLE ABOVE NORMAL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 235 AM WEDNESDAY...THE MEDIUM RANGE BEGINS WITH A VERY BROAD
TROUGH OVER THE EASTERN HALF OF THE COUNTRY. HOWEVER...A STRONG
SHORT WAVE TROUGH DIVING OUT OF THE UPPER MIDWEST SATURDAY NIGHT
WILL SHARPEN THE LONG WAVE PATTERN...BRINGING A COLD FRONT WILL
SIGNIFICANTLY COLDER AIR INTO THE AREA ON SUNDAY. WITH WEAK RIDGING
DOMINATING THE LOW LEVELS ACROSS THE REGION...MOISTURE WILL BE NON
EXISTENT AHEAD OF THIS FRONT...BUT SMALL POPS WILL BE CARRIED ALONG
THE TENN BORDER FOR NW FLOW MOISTURE BEHIND THE FRONT. THE MOST
OBVIOUS IMPACT OF THE FRONT WILL BE TO BRING TEMPERATURES BELOW
CLIMO FOR A COUPLE OF DAYS.
THE LATTER HALF OF THE EXTENDED WILL SEE MODERATING TEMPS...AS THE
EASTERN TROUGH PROGRESSES QUICKLY OFF THE EAST COAST...LEAVING
BEHIND A LOW AMPLITUDE/QUASI-ZONAL FLOW REGIME ACROSS MUCH OF THE
CONUS THROUGH MID-WEEK. THE WEATHER SHOULD ALSO BE DRY FOR A
CHANGE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...MID MORNING TAF UPDATE REQUIRES NO MAJOR CHANGES. OTHER
THAN SOME HIGH CLOUDS... THE WEATHER WILL BE FAIR THROUGH THE DAY.
THE NEARLY CALM WIND SHOULD BECOME LIGHT NE THIS MORNING...AND THEN
VEER TO ESE DURING THE AFTN. A WARM FRONT WILL APPROACH THE REGION
FROM THE SOUTH TONIGHT...WITH MVFR CIGS EXPECTED TOWARD THE END OF
THE TAF PERIOD.
ELSEWHERE...WINDS WILL GENERALLY BE OUT OF THE N TO NE THIS
MORNING...WITH LIGHT EASTERLY WINDS THIS AFTN OVER THE UPSTATE...AND
SOUTH AT KAVL/KHKY. A WARM FRONT WILL SPREAD CLOUDS AND FEW SHRA
BACK ACROSS THE REGION TONIGHT. CIGS SHOULD FALL THROUGH THE MVFR
RANGE LATE TONIGHT. THE MODEL GUIDANCE TAKES CIGS DOWN INTO THE
LIFR/VLIFR RANGE BETWEEN 12 AND 15 UTC AT MANY SITES...WHICH IS JUST
OUTSIDE THE VALID PERIOD OF THE TAF. HOPEFULLY A COUPLE DAYS WITH
ABOVE NORMAL TEMPS WILL DRY OUT AND WARM UP THE GROUND ENUF THAT IFR
OR LOWER CIGS WILL HOLD OFF UNTIL PCPN RATES PICK UP LATER ON FRIDAY.
OUTLOOK... AN APPROACHING LOW PRESSURE SYSTEM THURSDAY WILL PRODUCE
CEILING AND VISIBILITY RESTRICTIONS IN PRECIPITATION AND LOW CIGS
THROUGH THURSDAY NIGHT. CONDITIONS SHOULD IMPROVE DURING THE DAY ON
FRIDAY...THOUGH THERE IS A CHANCE THAT CONDITIONS WON/T IMPROVE
UNTIL FRIDAY NIGHT. FAIR WEATHER IS THEN EXPECTED SAT AND SUN.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LGL/MCAVOY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...LGL/MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
635 AM EST WED JAN 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH TODAY. A COLD FRONT AND
LOW PRESSURE WILL APPROACH THE CAROLINAS FROM THE WEST ON THURSDAY
AND PUSH EAST OF THE AREA ON FRIDAY. WEAK HIGH PRESSURE WILL BUILD
IN FROM THE WEST FRIDAY AND SATURDAY...BEFORE ANOTHER FRONT BRINGS
MUCH COOLER AIR TO THE REGION SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 635 AM WEDNESDAY...AN AREA OF LOW CLOUDS AND FOG CONTINUE TO
SKIRT THE SE PERIPHERY OF THE FORECAST AREA THIS MORNING. HOPEFULLY
IT WILL CONTINUE MOVING SE...BUT THE RUC BNDRY LAYER RH/S IMPLY THAT
IT COULD SPREAD A LITTLE FATHER WEST. WE/LL KEEP AN EYE ON IT.
AS OF 355 AM WEDNESDAY...THE AREA OF DENSE FOG AND LOW CLOUDS HAS
INDEED BEEN PUSHING SLOWLY SOUTHWARD ACROSS THE FA. ACTUALLY...THE
GRIDS HAVE DONE A PRETTY GOOD JOB CAPTURING THIS TREND...AT LEAST
BASED ON WHAT I CAN DISCERN ON THE FOG PRODUCT. THE REST OF THE NEAR
TERM LOOKS GOOD AND ONLY A FEW TWEAKS WERE MADE.
PREVIOUS DISCUSSION...
A BACK DOOR COLD FRONT WILL PUSH ACROSS THE FA EARLY THIS MORNING.
JUST ALONG AND AHEAD OF THE FRONT...AREAS OF FOG AND STRATUS HAVE
DEVELOPED OVER THE SRN NC PIEDMONT AND OVER THE NW PIEDMONT OF SOUTH
CAROLINA. HOWEVER...BUFKIT SOUNDINGS IMPLY THAT DRIER AIR SHOULD MIX
OUT THE FOG AND STRATUS OVER THE NC PIEDMONT IN SHORT ORDER...AND
PUSH IT GRADUALLY SOUTHWARD OVER THE ERN SC UPSTATE. I DON/T THINK
ANY LOW CLOUDS WILL LAST PAST ABOUT 6 AM...AND THEY MAY EVEN MIX OUT
BEFORE THAT. OTHERWISE HIGH CLOUDS WILL GRADUALLY THICKEN AND LOWER
DURING THE COURSE OF THE DAY AS AN UPPER LOW BEGINS TO LIFT OUT
ACROSS THE SRN PLAINS. THERE IS A WELL DEFINED WARM FRONTAL BNDRY
DOWN ALONG THE GULF COAST...AND AS THIS STARTS TO LIFT NORTH IN
RESPONSE TO THE APPROACHING TROUGH...LOW CLOUDS SHOULD SPREAD ACROSS
THE FA LATER TONIGHT. PATCHY AREAS OF RAIN SHOULD ALSO BEGIN TO
DEVELOP...PARTICULARLY ALONG THE SRN AND ERN SLOPES OF THE BLUE
RIDGE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 AM WEDNESDAY...LOW LEVEL FLOW WILL CONTINUE TO INCREASE
DURING THE DAY THURSDAY...RESULTING IN GRADUAL INCREASE OF MOISTURE
LEVELS...AS WELL AS IN INCREASE IN ISENTROPIC UPGLIDE AND ESPECIALLY
MECHANICAL/UPSLOPE-INDUCED LIFT. THIS WILL RESULT IN GRADUAL
INCREASE IN POPS THROUGHOUT THE DAY...WITH LIKELY POPS ACROSS THE
SOUTHWEST NC MTNS BY AFTERNOON...EXPANDING TO THE REMAINDER OF THE
NC MTNS BY 00Z FRIDAY...AS DEEP MOISTURE PUSHES INTO THE REGION IN
ADVANCE OF FRONTAL ZONE. THE VERY MOIST FRONTAL ZONE WILL SWEEP
ACROSS THE AREA THURSDAY NIGHT...WARRANTING CATEGORICAL POPS IN ALL
AREAS BY 12Z FRIDAY. PROGGED CAPE VALUES ARE VERY LOW...BUT NON-ZERO
THROUGHOUT THE EVENT...ENOUGH TO WARRANT A SLIGHT CHANCE THUNDER
MENTION IN SOME AREAS. CONSIDERING THE VERY STRONG DEEP-LAYER
SHEAR...A LOW-END SEVERE WEATHER THREAT WILL EXIST...WITH THE
POSSIBILITY OF A DISCRETE CELL OR TWO AHEAD OF THE FRONT THURSDAY
AFTERNOON/EVENING...THEN WITH A POTENTIAL SHALLOW QLCS ALONG THE
FRONT THURSDAY NIGHT.
WEAK LOW PRESSURE DEVELOPING THE FRONT TO OUR SOUTHWEST IS EXPECTED
TO RESULT IN THE BOUNDARY SLOWING DOWN A BIT AS IT PUSHES EAST OF
THE REGION EARLY FRIDAY...SO POPS WILL BE RETAINED ACROSS THE
EASTERN AND SOUTHERN ZONES DURING THE MORNING. OTHERWISE...STRONG
COLD ADVECTION WILL RESULT IN TEMPS FALLING THROUGH THE DAY ACROSS
THE MTNS. NEVERTHELESS...THE POST-FRONTAL AIR MASS IS STILL OF
PACIFIC ORIGINS...SO TEMPS THROUGH THE REMAINDER OF THE SHORT TERM
WILL REMAIN A LITTLE ABOVE NORMAL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 235 AM WEDNESDAY...THE MEDIUM RANGE BEGINS WITH A VERY BROAD
TROUGH OVER THE EASTERN HALF OF THE COUNTRY. HOWEVER...A STRONG
SHORT WAVE TROUGH DIVING OUT OF THE UPPER MIDWEST SATURDAY NIGHT
WILL SHARPEN THE LONG WAVE PATTERN...BRINGING A COLD FRONT WILL
SIGNIFICANTLY COLDER AIR INTO THE AREA ON SUNDAY. WITH WEAK RIDGING
DOMINATING THE LOW LEVELS ACROSS THE REGION...MOISTURE WILL BE NON
EXISTENT AHEAD OF THIS FRONT...BUT SMALL POPS WILL BE CARRIED ALONG
THE TENN BORDER FOR NW FLOW MOISTURE BEHIND THE FRONT. THE MOST
OBVIOUS IMPACT OF THE FRONT WILL BE TO BRING TEMPERATURES BELOW
CLIMO FOR A COUPLE OF DAYS.
THE LATTER HALF OF THE EXTENDED WILL SEE MODERATING TEMPS...AS THE
EASTERN TROUGH PROGRESSES QUICKLY OFF THE EAST COAST...LEAVING
BEHIND A LOW AMPLITUDE/QUASI-ZONAL FLOW REGIME ACROSS MUCH OF THE
CONUS THROUGH MID-WEEK. THE WEATHER SHOULD ALSO BE DRY FOR A
CHANGE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...OTHER THAN SOME HIGH CLOUDS...THE WEATHER WILL BE FAIR
THROUGH THE DAY. WINDS WILL BE LIGHT NE THIS MORNING...AND THEY
SHOULD VEER TO ESE BY THIS AFTN. A WARM FRONT WILL APPROACH THE
REGION FROM THE SOUTH TONIGHT...WITH MVFR CIGS EXPECTED TOWARD THE
END OF THE TAF PERIOD.
ELSEWHERE...WINDS WILL GENERALLY BE OUT OF THE N TO NE THIS
MORNING...WITH LIGHT EASTERLY WINDS THIS AFTN OVER THE UPSTATE...AND
SOUTH AT KAVL/KHKY. A WARM FRONT WILL SPREAD CLOUDS AND FEW SHRA
BACK ACROSS THE REGION TONIGHT. CIGS SHOULD FALL THROUGH THE MVFR
RANGE LATE TONIGHT. THE MODEL GUIDANCE TAKES CIGS DOWN INTO THE
LIFR/VLIFR RANGE BETWEEN 12 AND 15 UTC AT MANY SITES...WHICH IS JUST
OUTSIDE THE VALID PERIOD OF THE TAF. HOPEFULLY A COUPLE DAYS WITH
ABOVE NORMAL TEMPS WILL DRY OUT AND WARM UP THE GROUND ENUF THAT IFR
OR LOWER CIGS WILL HOLD OFF UNTIL PCPN RATES PICK UP LATER ON FRIDAY.
OUTLOOK... AN APPROACHING LOW PRESSURE SYSTEM THURSDAY WILL PRODUCE
CEILING AND VISIBILITY RESTRICTIONS IN PRECIPITATION AND LOW CIGS
THROUGH THURSDAY NIGHT. CONDITIONS SHOULD IMPROVE DURING THE DAY ON
FRIDAY...THOUGH THERE IS A CHANCE THAT CONDITIONS WON/T IMPROVE
UNTIL FRIDAY NIGHT. FAIR WEATHER IS THEN EXPECTED SAT AND SUN.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JDL
NEAR TERM...MCAVOY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1153 AM CST WED JAN 25 2012
.PREV DISCUSSION... /ISSUED 944 AM CST WED JAN 25 2012/
UPDATE...
SHOWERS ARE MOVING ACROSS NORTHEASTERN ARKANSAS...THE MISSOURI
BOOTHEEL...AND WESTERN TENNESSEE. MODELS ARE SHOWING ADDITIONAL
SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHERN MISSISSIPPI AND
SOUTHERN ARKANSAS LATER THIS MORNING AND INTO THE AFTERNOON HOURS.
A LARGE AREA OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED AHEAD OF A
COLD FRONT AND LOW PRESSURE SYSTEM OVER TEXAS AND WILL CONTINUE
MOVING EAST. FORECAST LOOKS GOOD AT THIS TIME AND NO UPDATE IS NEEDED
TO GRIDS.
RRH
&&
.PREV DISCUSSION... /ISSUED 719 AM CST WED JAN 25 2012/
UPDATE...WARM FRONT LOCATED ALONG THE GULF COAST THIS MORNING IS
BEGINNING TO SHOW SIGNS OF MOVING NORTH...AND TOWARDS THE MID
SOUTH LATER TODAY. BASED ON LATEST CONVECTIVE TRENDS AND
THE RUC INDICATING INCREASING ELEVATED INSTABILITY ACROSS THE
FORECAST AREA...INCREASED MENTION OF ELEVATED THUNDER IN THE
FORECAST FOR THE REMAINDER OF THE DAY.
UPDATED GRIDS ALREADY PUBLISHED.
CJC
&&
.PREV DISCUSSION... /ISSUED 456 AM CST WED JAN 25 2012/
DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER TRENDS THIS
MORNING PLACE AN UPPER LEVEL LOW NEAR EL PASO TEXAS WITH A SURFACE
LOW CENTERED JUST SOUTHWEST OF SAN ANTONIO TEXAS. A WARM FRONT
EXTENDS FROM THIS SURFACE LOW UP TO WACO TEXAS AND THEN BACK
TOWARDS THE LOUISIANA/ALABAMA COAST AND FLORIDA PANHANDLE. CLOUDY
SKIES AND RAIN ENCOMPASS MUCH OF THE MID SOUTH AS OF THIS
MORNING/S FORECAST ISSUANCE. AS OF 4 AM CST...TEMPERATURES RANGE
FROM THE UPPER 30S TO LOWER 40S ACROSS THE NORTHERN THIRD OF THE
MID SOUTH AND MIDDLE 40S TO AROUND 50 DEGREES ACROSS AREAS SOUTH
OF I-40. THE POTENTIAL FOR A STRONG THUNDERSTORM OR TWO ACROSS
NORTHEAST MISSISSIPPI THURSDAY MORNING INTO EARLY THURSDAY
AFTERNOON IS THE PRIMARY CONCERN IN THIS MORNING/S FORECAST.
SHORT TERM...(TODAY THROUGH THURSDAY)...RAIN HAS FINALLY
ARRIVED OVERNIGHT ACROSS THE MID SOUTH COURTESY OF ISENTROPIC
ASCENT LIFTING GULF OF MEXICO MOISTURE AND PRODUCING OVERRUNNING
RAIN NORTH OF THE WARM FRONT...CURRENTLY SITUATED ALONG THE
LOUISIANA/ALABAMA COAST THIS MORNING. MODELS ARE IN DECENT
AGREEMENT WITH THIS OVERRUNNING RAIN OCCURRING THIS MORNING ACROSS
THE ENTIRE MID SOUTH. THE ABOVE MENTIONED WARM FRONT WILL BEGIN
LIFTING NORTH TODAY...AND REACHING AS FAR NORTH AS PORTIONS OF
NORTHEAST MISSISSIPPI AS EARLY AS LATE AFTERNOON/EARLY THIS
EVENING AS THE UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW BEGIN TO
LIFT NORTHEAST INTO THE LOWER MISSISSIPPI VALLEY. KEPT LOWER POPS
ACROSS NORTHEAST MISSISSIPPI THIS AFTERNOON AS BEST COVERAGE BY
FAR WILL REMAIN NORTH OF THE WARM FRONT. OVERALL INSTABILITY WILL
REMAIN LOW THROUGHOUT THE DAY. HOWEVER...DID ADD ISOLATED THUNDER
FOR THE SOUTHERN TIER OR TWO OF COUNTIES ACROSS NORTH MISSISSIPPI
FOR LATE AFTERNOON AS THE WARM FRONT APPROACHES. HIGH TEMPERATURES
TODAY WILL RANGE FROM THE LOWER TO MIDDLE 40S ACROSS NORTHEAST
ARKANSAS TO FAR NORTHWEST TENNESSEE...AND UPPER 50S TO LOWER 60S
IN CLOSER PROXIMITY TO THE APPROACHING WARM FRONT.
THE WARM FRONT WILL BISECT THE MID SOUTH FROM SOUTHWEST TO
NORTHEAST TONIGHT AS A SURFACE AND UPPER LEVEL LOW MOVE JUST TO
THE SOUTH OF THE FORECAST AREA INTO THURSDAY. SHOWERS AND A FEW
THUNDERSTORMS ARE EXPECTED ACROSS THE MID SOUTH TONIGHT INTO
THURSDAY. DESPITE FAVORABLE UPPER LEVEL DIVERGENCE /LIFT/ AND
SHEAR...NOT OVERLY IMPRESSED WITH QUALITY OF INSTABILITY FORECAST
ACROSS THE MID SOUTH. BEST INSTABILITY AXIS WILL REMAIN JUST TO
THE SOUTH OF THE AREA AND WIDESPREAD RAIN SHOWERS/EXTENSIVE CLOUD
COVER HAVE RESULTED IN LOW CONFIDENCE ON STRONG/SEVERE
THUNDERSTORM THREAT DURING THIS TIME FRAME. NONETHELESS...DAY/EVENING
SHIFTS WILL CONTINUE TO MONITOR TRENDS AND ADJUST FORECAST AS NECESSARY
IF THIS INSTABILITY AXIS CREEPS FURTHER NORTH THAN CURRENTLY
INDICATED BY THE LATEST SHORT TERM MODELS.
LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)...
RAIN SHOWERS WILL GRADUALLY COME TO AN END THURSDAY NIGHT AS COOL HIGH
PRESSURE BUILDS BACK INTO THE MID SOUTH BY FRIDAY MORNING. MODELS
INDICATE ANOTHER COLD FRONT WILL MOVE INTO THE AREA FRIDAY NIGHT.
HOWEVER...ANALYSIS OF MODEL SOUNDINGS INDICATES LOW LEVEL
PRECIPITATION WILL REMAIN NEARLY NON-EXISTENT AND WILL RESULT IN
SOME MID/HIGH LEVEL CLOUDS PUSHING ACROSS THE AREA FRIDAY NIGHT
INTO SATURDAY MORNING. 00Z GFS/ECMWF LONG TERM MODELS INDICATE
SURFACE HIGH PRESSURE WILL BUILD BACK IN AGAIN ACROSS THE LOWER
MISSISSIPPI VALLEY SATURDAY THROUGH MONDAY WITH CYCLONIC FLOW
ALOFT. CHANCES FOR RAIN SHOWERS WILL RETURN BY NEXT TUESDAY AS
HIGH PRESSURE MOVES EAST AND ANOTHER COLD FRONT BEGINS TO MOVE
FROM THE CENTRAL/SOUTHERN PLAINS INTO THE MIDDLE/LOWER MISSISSIPPI
VALLEYS BY THE MIDDLE OF NEXT WEEK.
CJC
&&
.AVIATION...
18Z TAF CYCLE
RAIN HAS PUSHED NORTH AND IS NOW CONFINED TO NORTHWEST TENNESSEE
AND NORTHERN ARKANSAS. CLEARING HAS TAKEN PLACE ACROSS NORTHEAST
MISSISSIPPI WITH VARYING CONDITIONS BETWEEN VFR AND MVFR IN
CLOUD PATCHES. THINK THE CURRENT TREND WILL CONTINUE FOR THE REST
OF THE AFTERNOON. BY THIS EVENING...CLOUDS SHOULD FILL IN AND LOWER
AGAIN WITH RAIN REDEVELOPING AREAWIDE. A FEW THUNDERSTORMS ARE
ALSO POSSIBLE...PARTICULARLY ALONG AND SOUTH OF I-40. IFR
CONDITIONS OR LIFR CONDITIONS SHOULD OVERSPREAD PARTS OF THE AREA
LATE TONIGHT AND THURSDAY MORNING.
WINDS WILL BE SOUTHERLY SOUTH OF I-40...AND EASTERLY OR NORTHEASTERLY
ALONG AND NORTH. AS THE LOW BISECTS THE AREA THURSDAY MORNING...WINDS
WILL BACK NORTH.
BORGHOFF
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 55 53 60 39 / 90 100 100 50
MKL 52 49 59 38 / 100 90 100 50
JBR 46 44 49 35 / 100 100 100 30
TUP 62 57 69 42 / 70 80 100 70
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
944 AM CST WED JAN 25 2012
.UPDATE...
SHOWERS ARE MOVING ACROSS NORTHEASTERN ARKANSAS...THE MISSOURI
BOOTHEEL...AND WESTERN TENNESSEE. MODELS ARE SHOWING ADDITIONAL
SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHERN MISSISSIPPI AND
SOUTHERN ARKANSAS LATER THIS MORNING AND INTO THE AFTERNOON HOURS.
A LARGE AREA OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED AHEAD OF A
COLD FRONT AND LOW PRESSURE SYSTEM OVER TEXAS AND WILL CONTINUE
MOVING EAST. FORECAST LOOKS GOOD AT THIS TIME AND NO UPDATE IS NEEDED
TO GRIDS.
RRH
&&
.PREV DISCUSSION... /ISSUED 719 AM CST WED JAN 25 2012/
UPDATE...WARM FRONT LOCATED ALONG THE GULF COAST THIS MORNING IS
BEGINNING TO SHOW SIGNS OF MOVING NORTH...AND TOWARDS THE MID
SOUTH LATER TODAY. BASED ON LATEST CONVECTIVE TRENDS AND
THE RUC INDICATING INCREASING ELEVATED INSTABILITY ACROSS THE
FORECAST AREA...INCREASED MENTION OF ELEVATED THUNDER IN THE
FORECAST FOR THE REMAINDER OF THE DAY.
UPDATED GRIDS ALREADY PUBLISHED.
CJC
PREV DISCUSSION... /ISSUED 456 AM CST WED JAN 25 2012/
DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER TRENDS THIS
MORNING PLACE AN UPPER LEVEL LOW NEAR EL PASO TEXAS WITH A SURFACE
LOW CENTERED JUST SOUTHWEST OF SAN ANTONIO TEXAS. A WARM FRONT
EXTENDS FROM THIS SURFACE LOW UP TO WACO TEXAS AND THEN BACK
TOWARDS THE LOUISIANA/ALABAMA COAST AND FLORIDA PANHANDLE. CLOUDY
SKIES AND RAIN ENCOMPASS MUCH OF THE MID SOUTH AS OF THIS
MORNING/S FORECAST ISSUANCE. AS OF 4 AM CST...TEMPERATURES RANGE
FROM THE UPPER 30S TO LOWER 40S ACROSS THE NORTHERN THIRD OF THE
MID SOUTH AND MIDDLE 40S TO AROUND 50 DEGREES ACROSS AREAS SOUTH
OF I-40. THE POTENTIAL FOR A STRONG THUNDERSTORM OR TWO ACROSS
NORTHEAST MISSISSIPPI THURSDAY MORNING INTO EARLY THURSDAY
AFTERNOON IS THE PRIMARY CONCERN IN THIS MORNING/S FORECAST.
SHORT TERM...(TODAY THROUGH THURSDAY)...RAIN HAS FINALLY
ARRIVED OVERNIGHT ACROSS THE MID SOUTH COURTESY OF ISENTROPIC
ASCENT LIFTING GULF OF MEXICO MOISTURE AND PRODUCING OVERRUNNING
RAIN NORTH OF THE WARM FRONT...CURRENTLY SITUATED ALONG THE
LOUISIANA/ALABAMA COAST THIS MORNING. MODELS ARE IN DECENT
AGREEMENT WITH THIS OVERRUNNING RAIN OCCURRING THIS MORNING ACROSS
THE ENTIRE MID SOUTH. THE ABOVE MENTIONED WARM FRONT WILL BEGIN
LIFTING NORTH TODAY...AND REACHING AS FAR NORTH AS PORTIONS OF
NORTHEAST MISSISSIPPI AS EARLY AS LATE AFTERNOON/EARLY THIS
EVENING AS THE UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW BEGIN TO
LIFT NORTHEAST INTO THE LOWER MISSISSIPPI VALLEY. KEPT LOWER POPS
ACROSS NORTHEAST MISSISSIPPI THIS AFTERNOON AS BEST COVERAGE BY
FAR WILL REMAIN NORTH OF THE WARM FRONT. OVERALL INSTABILITY WILL
REMAIN LOW THROUGHOUT THE DAY. HOWEVER...DID ADD ISOLATED THUNDER
FOR THE SOUTHERN TIER OR TWO OF COUNTIES ACROSS NORTH MISSISSIPPI
FOR LATE AFTERNOON AS THE WARM FRONT APPROACHES. HIGH TEMPERATURES
TODAY WILL RANGE FROM THE LOWER TO MIDDLE 40S ACROSS NORTHEAST
ARKANSAS TO FAR NORTHWEST TENNESSEE...AND UPPER 50S TO LOWER 60S
IN CLOSER PROXIMITY TO THE APPROACHING WARM FRONT.
THE WARM FRONT WILL BISECT THE MID SOUTH FROM SOUTHWEST TO
NORTHEAST TONIGHT AS A SURFACE AND UPPER LEVEL LOW MOVE JUST TO
THE SOUTH OF THE FORECAST AREA INTO THURSDAY. SHOWERS AND A FEW
THUNDERSTORMS ARE EXPECTED ACROSS THE MID SOUTH TONIGHT INTO
THURSDAY. DESPITE FAVORABLE UPPER LEVEL DIVERGENCE /LIFT/ AND
SHEAR...NOT OVERLY IMPRESSED WITH QUALITY OF INSTABILITY FORECAST
ACROSS THE MID SOUTH. BEST INSTABILITY AXIS WILL REMAIN JUST TO
THE SOUTH OF THE AREA AND WIDESPREAD RAIN SHOWERS/EXTENSIVE CLOUD
COVER HAVE RESULTED IN LOW CONFIDENCE ON STRONG/SEVERE
THUNDERSTORM THREAT DURING THIS TIMEFRAME. NONETHELESS...DAY/EVENING
SHIFTS WILL CONTINUE TO MONITOR TRENDS AND ADJUST FORECAST AS NECESSARY
IF THIS INSTABILITY AXIS CREEPS FURTHER NORTH THAN CURRENTLY
INDICATED BY THE LATEST SHORT TERM MODELS.
LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)...
RAIN SHOWERS WILL GRADUALLY COME TO AN END THURSDAY NIGHT AS COOL HIGH
PRESSURE BUILDS BACK INTO THE MID SOUTH BY FRIDAY MORNING. MODELS
INDICATE ANOTHER COLD FRONT WILL MOVE INTO THE AREA FRIDAY NIGHT.
HOWEVER...ANALYSIS OF MODEL SOUNDINGS INDICATES LOW LEVEL
PRECIPITATION WILL REMAIN NEARLY NON-EXISTENT AND WILL RESULT IN
SOME MID/HIGH LEVEL CLOUDS PUSHING ACROSS THE AREA FRIDAY NIGHT
INTO SATURDAY MORNING. 00Z GFS/ECMWF LONG TERM MODELS INDICATE
SURFACE HIGH PRESSURE WILL BUILD BACK IN AGAIN ACROSS THE LOWER
MISSISSIPPI VALLEY SATURDAY THROUGH MONDAY WITH CYCLONIC FLOW
ALOFT. CHANCES FOR RAIN SHOWERS WILL RETURN BY NEXT TUESDAY AS
HIGH PRESSURE MOVES EAST AND ANOTHER COLD FRONT BEGINS TO MOVE
FROM THE CENTRAL/SOUTHERN PLAINS INTO THE MIDDLE/LOWER MISSISSIPPI
VALLEYS BY THE MIDDLE OF NEXT WEEK.
CJC
&&
.AVIATION...
12Z TAF CYCLE
LIGHT RAIN IS FALLING OUT OF FAIRLY A FAIRLY HIGH CLOUD
DECK...RANGING FROM NEARLY 10000 FEET AT MKL TO 5000 FEET AT MEM.
CIGS WILL GRADUALLY LOWER DURING THE DAY AND RAIN WILL BECOME
HEAVIER. EXPECT MVFR CIGS TO PREVAIL AT ALL SITES TODAY WITH MVFR
TO VFR VIS. AFTER SUNSET...IFR CIGS ARE EXPECTED WITH POSSIBLE
LIFR CIGS TOWARD MORNING. INCLUDED TEMPO 400 FT CIGS AT JBR AND
MEM PRIOR TO SUNRISE LATE TONIGHT. WINDS WILL REMAIN GENERALLY
FROM THE EAST AS A SURFACE LOW DEVELOPS OVER EAST TEXAS.
JDS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 55 53 60 39 / 90 100 100 50
MKL 52 49 59 38 / 100 90 100 50
JBR 46 44 49 35 / 100 100 100 30
TUP 62 57 69 42 / 70 80 100 70
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
719 AM CST WED JAN 25 2012
.UPDATE...WARM FRONT LOCATED ALONG THE GULF COAST THIS MORNING IS
BEGINNING TO SHOW SIGNS OF MOVING NORTH...AND TOWARDS THE MID
SOUTH LATER TODAY. BASED ON LATEST CONVECTIVE TRENDS AND
THE RUC INDICATING INCREASING ELEVATED INSTABILITY ACROSS THE
FORECAST AREA...INCREASED MENTION OF ELEVATED THUNDER IN THE
FORECAST FOR THE REMAINDER OF THE DAY.
UPDATED GRIDS ALREADY PUBLISHED.
CJC
&&
.PREV DISCUSSION... /ISSUED 534 AM CST WED JAN 25 2012/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 456 AM CST WED JAN 25 2012/
DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER TRENDS THIS
MORNING PLACE AN UPPER LEVEL LOW NEAR EL PASO TEXAS WITH A SURFACE
LOW CENTERED JUST SOUTHWEST OF SAN ANTONIO TEXAS. A WARM FRONT
EXTENDS FROM THIS SURFACE LOW UP TO WACO TEXAS AND THEN BACK
TOWARDS THE LOUISIANA/ALABAMA COAST AND FLORIDA PANHANDLE. CLOUDY
SKIES AND RAIN ENCOMPASS MUCH OF THE MID SOUTH AS OF THIS
MORNING/S FORECAST ISSUANCE. AS OF 4 AM CST...TEMPERATURES RANGE
FROM THE UPPER 30S TO LOWER 40S ACROSS THE NORTHERN THIRD OF THE
MID SOUTH AND MIDDLE 40S TO AROUND 50 DEGREES ACROSS AREAS SOUTH
OF I-40. THE POTENTIAL FOR A STRONG THUNDERSTORM OR TWO ACROSS
NORTHEAST MISSISSIPPI THURSDAY MORNING INTO EARLY THURSDAY
AFTERNOON IS THE PRIMARY CONCERN IN THIS MORNING/S FORECAST.
SHORT TERM...(TODAY THROUGH THURSDAY)...RAIN HAS FINALLY
ARRIVED OVERNIGHT ACROSS THE MID SOUTH COURTESY OF ISENTROPIC
ASCENT LIFTING GULF OF MEXICO MOISTURE AND PRODUCING OVERRUNNING
RAIN NORTH OF THE WARM FRONT...CURRENTLY SITUATED ALONG THE
LOUISIANA/ALABAMA COAST THIS MORNING. MODELS ARE IN DECENT
AGREEMENT WITH THIS OVERRUNNING RAIN OCCURRING THIS MORNING ACROSS
THE ENTIRE MID SOUTH. THE ABOVE MENTIONED WARM FRONT WILL BEGIN
LIFTING NORTH TODAY...AND REACHING AS FAR NORTH AS PORTIONS OF
NORTHEAST MISSISSIPPI AS EARLY AS LATE AFTERNOON/EARLY THIS
EVENING AS THE UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW BEGIN TO
LIFT NORTHEAST INTO THE LOWER MISSISSIPPI VALLEY. KEPT LOWER POPS
ACROSS NORTHEAST MISSISSIPPI THIS AFTERNOON AS BEST COVERAGE BY
FAR WILL REMAIN NORTH OF THE WARM FRONT. OVERALL INSTABILITY WILL
REMAIN LOW THROUGHOUT THE DAY. HOWEVER...DID ADD ISOLATED THUNDER
FOR THE SOUTHERN TIER OR TWO OF COUNTIES ACROSS NORTH MISSISSIPPI
FOR LATE AFTERNOON AS THE WARM FRONT APPROACHES. HIGH TEMPERATURES
TODAY WILL RANGE FROM THE LOWER TO MIDDLE 40S ACROSS NORTHEAST
ARKANSAS TO FAR NORTHWEST TENNESSEE...AND UPPER 50S TO LOWER 60S
IN CLOSER PROXIMITY TO THE APPROACHING WARM FRONT.
THE WARM FRONT WILL BISECT THE MID SOUTH FROM SOUTHWEST TO
NORTHEAST TONIGHT AS A SURFACE AND UPPER LEVEL LOW MOVE JUST TO
THE SOUTH OF THE FORECAST AREA INTO THURSDAY. SHOWERS AND A FEW
THUNDERSTORMS ARE EXPECTED ACROSS THE MID SOUTH TONIGHT INTO
THURSDAY. DESPITE FAVORABLE UPPER LEVEL DIVERGENCE /LIFT/ AND
SHEAR...NOT OVERLY IMPRESSED WITH QUALITY OF INSTABILITY FORECAST
ACROSS THE MID SOUTH. BEST INSTABILITY AXIS WILL REMAIN JUST TO
THE SOUTH OF THE AREA AND WIDESPREAD RAIN SHOWERS/EXTENSIVE CLOUD
COVER HAVE RESULTED IN LOW CONFIDENCE ON STRONG/SEVERE
THUNDERSTORM THREAT DURING THIS TIMEFRAME. NONETHELESS...DAY/EVENING
SHIFTS WILL CONTINUE TO MONITOR TRENDS AND ADJUST FORECAST AS NECESSARY
IF THIS INSTABILITY AXIS CREEPS FURTHER NORTH THAN CURRENTLY
INDICATED BY THE LATEST SHORT TERM MODELS.
LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)...
RAIN SHOWERS WILL GRADUALLY COME TO AN END THURSDAY NIGHT AS COOL HIGH
PRESSURE BUILDS BACK INTO THE MID SOUTH BY FRIDAY MORNING. MODELS
INDICATE ANOTHER COLD FRONT WILL MOVE INTO THE AREA FRIDAY NIGHT.
HOWEVER...ANALYSIS OF MODEL SOUNDINGS INDICATES LOW LEVEL
PRECIPITATION WILL REMAIN NEARLY NON-EXISTENT AND WILL RESULT IN
SOME MID/HIGH LEVEL CLOUDS PUSHING ACROSS THE AREA FRIDAY NIGHT
INTO SATURDAY MORNING. 00Z GFS/ECMWF LONG TERM MODELS INDICATE
SURFACE HIGH PRESSURE WILL BUILD BACK IN AGAIN ACROSS THE LOWER
MISSISSIPPI VALLEY SATURDAY THROUGH MONDAY WITH CYCLONIC FLOW
ALOFT. CHANCES FOR RAIN SHOWERS WILL RETURN BY NEXT TUESDAY AS
HIGH PRESSURE MOVES EAST AND ANOTHER COLD FRONT BEGINS TO MOVE
FROM THE CENTRAL/SOUTHERN PLAINS INTO THE MIDDLE/LOWER MISSISSIPPI
VALLEYS BY THE MIDDLE OF NEXT WEEK.
CJC
&&
.AVIATION...
12Z TAF CYCLE
LIGHT RAIN IS FALLING OUT OF FAIRLY A FAIRLY HIGH CLOUD
DECK...RANGING FROM NEARLY 10000 FEET AT MKL TO 5000 FEET AT MEM.
CIGS WILL GRADUALLY LOWER DURING THE DAY AND RAIN WILL BECOME
HEAVIER. EXPECT MVFR CIGS TO PREVAIL AT ALL SITES TODAY WITH MVFR
TO VFR VIS. AFTER SUNSET...IFR CIGS ARE EXPECTED WITH POSSIBLE
LIFR CIGS TOWARD MORNING. INCLUDED TEMPO 400 FT CIGS AT JBR AND
MEM PRIOR TO SUNRISE LATE TONIGHT. WINDS WILL REMAIN GENERALLY
FROM THE EAST AS A SURFACE LOW DEVELOPS OVER EAST TEXAS.
JDS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 55 53 60 39 / 90 100 100 50
MKL 52 49 59 38 / 100 90 100 50
JBR 46 44 49 35 / 100 100 100 30
TUP 62 57 69 42 / 70 80 100 70
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1147 AM CST WED JAN 25 2012
.DISCUSSION...
LINE OF THUNDERSTORMS FROM NEAR LFK TO IAH TO SGR TO FREEPORT
MOVING EAST AT 25-35 KNOTS WITH INDIVIDUAL STORMS MOVING
NORTHEAST. LLJ AHEAD OF THE BOUNDARY AIDING SE SFC WINDS
15-25KTS. STORMS WILL USHER IN WINDS OF 15 TO 40 KNOTS STRONGER IN
EMBEDDED BOWS AND NOTCHES. BACK EDGE OF STORM CLEARING CLL ATTM
AND SHOULD CLEAR ALL THE SITES BUT GLS BY 20Z. WINDS IN THE WAKE
OF THE STORMS SWINGING TO THE NW BUT WINDS LOOK TO BE LIGHTER THAN
WITH THE PASSAGE OF THE MESOL-LOW EARLIER THIS AM. CIGS DROPPING
TO AROUND 1000-2000 FT BKN/OVC WITH WRAP AROUND. VCSH POSSIBLE
LATE TONIGHT EARLY AM WITH THE UPPER TROUGH PASSAGE BUT MOISTURE
MAY BE LACKING AND MAY JUST BE MID LEVEL CLOUDS AND VIRGA.
WESTERLY WINDS TOMORROW WITH CIGS IMPROVING TO VFR.
45
&&
.PREV DISCUSSION... /ISSUED 1049 AM CST WED JAN 25 2012/
DISCUSSION...
DID A QUICK UPDATE TO CANCEL THE TORNADO WATCH OUT WEST AND EXTEND IT
UNTIL 2 PM OUT EAST. BASED ON CURRENT RADAR TRENDS...RAISED GRID RAINFALL
TOTALS. 42
PREV DISCUSSION... /ISSUED 1001 AM CST WED JAN 25 2012/
DISCUSSION...
LINE OF STRONG/SEVERE THUNDERSTORMS MAKING PROGRESS MOVING EASTWARD
ACROSS SOUTHEAST TEXAS THIS MORNING WITH A TORNADO WATCH IN EFFECT
UNTIL 11 AM. NORTHERN HALF OF THE LINE (ROUGHLY NORTH OF I-10) IS
MOVING FASTER THAN THE SOUTHERN HALF OF THE LINE. WE WILL PROBABLY
BE ISSUING ADDITIONAL FLOOD ADVISORIES TO COVER THE POTENTIAL FOR
WIDESPREAD 1 TO 3 INCH RAINFALL TOTALS ACROSS THE SOUTHERN HALF OF
THIS STORM COMPLEX...AND THIS AREA WILL ALSO BE CLOSELY MONITORED FOR
THE POTENTIAL FOR SEVERE STORM DEVELOPMENT. HIGHER RAINFALL TOTALS
CANNOT BE RULED OUT.
UPDATED THE MORNING FORECAST WITH HIGHER RAIN CHANCES EAST AND COOLER
TEMPERATURES WEST. 42
PREV DISCUSSION... /ISSUED 738 AM CST WED JAN 25 2012/
UPDATE...
EXTENDED THE TORNADO WATCH INTO CHAMBERS...LIBERTY...SAN JACINTO
COUNTIES...AND GALVESTON BAY.
PREV DISCUSSION... /ISSUED 634 AM CST WED JAN 25 2012/
AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES (MVFR) AND WIND GUSTS THAT COULD EXCEED 35 KTS WITHIN STRONGEST
STORMS. IN THE MEANTIME...A 50 KT LL JET HAS SHORT TERM WIND SHEAR
IN CURRENT PACKAGE...OR BEFORE THUNDERSTORMS ARRIVE. TIMING HAS THE
BULK OF CONVECTION OVER THE GREATER HOUSTON TERMINALS DURING THE
16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH AN EMBEDDED
STORM BOOK-ENDING THOSE TIMES. PRECIP BEGINNING TO FILL IN NICELY
AHEAD OF ONE-OF-TWO MAIN SQUALL LINES MOVING NE FROM SOUTH CENTRAL
TEXAS. THIS 50 KT LOW LEVEL JET AND AMPLE INFLOW INTO THE APPROACHING
MID-SURFACE LOW (NEAR KSAT) WILL AID IN KEEPING THE MAJORITY OF
THE DECKS AT IFR OR MVFR LEVELS...MORNING 20-25 SUSTAINED WINDS.
LINGERING -SHRA THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP
AROUND -RA THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER
OF PERIOD UNDER WESTERLY FLOW. 31
PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 48 60 42 63 / 100 30 30 10 10
HOUSTON (IAH) 72 52 63 45 65 / 100 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 100 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1049 AM CST WED JAN 25 2012
.DISCUSSION...
DID A QUICK UPDATE TO CANCEL THE TORNADO WATCH OUT WEST AND EXTEND IT
UNTIL 2 PM OUT EAST. BASED ON CURRENT RADAR TRENDS...RAISED GRID RAINFALL
TOTALS. 42
&&
.PREV DISCUSSION... /ISSUED 1001 AM CST WED JAN 25 2012/
DISCUSSION...
LINE OF STRONG/SEVERE THUNDERSTORMS MAKING PROGRESS MOVING EASTWARD
ACROSS SOUTHEAST TEXAS THIS MORNING WITH A TORNADO WATCH IN EFFECT
UNTIL 11 AM. NORTHERN HALF OF THE LINE (ROUGHLY NORTH OF I-10) IS
MOVING FASTER THAN THE SOUTHERN HALF OF THE LINE. WE WILL PROBABLY
BE ISSUING ADDITIONAL FLOOD ADVISORIES TO COVER THE POTENTIAL FOR
WIDESPREAD 1 TO 3 INCH RAINFALL TOTALS ACROSS THE SOUTHERN HALF OF
THIS STORM COMPLEX...AND THIS AREA WILL ALSO BE CLOSELY MONITORED FOR
THE POTENTIAL FOR SEVERE STORM DEVELOPMENT. HIGHER RAINFALL TOTALS
CANNOT BE RULED OUT.
UPDATED THE MORNING FORECAST WITH HIGHER RAIN CHANCES EAST AND COOLER
TEMPERATURES WEST. 42
PREV DISCUSSION... /ISSUED 738 AM CST WED JAN 25 2012/
UPDATE...
EXTENDED THE TORNADO WATCH INTO CHAMBERS...LIBERTY...SAN JACINTO
COUNTIES...AND GALVESTON BAY.
PREV DISCUSSION... /ISSUED 634 AM CST WED JAN 25 2012/
AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES (MVFR) AND WIND GUSTS THAT COULD EXCEED 35 KTS WITHIN STRONGEST
STORMS. IN THE MEANTIME...A 50 KT LL JET HAS SHORT TERM WIND SHEAR
IN CURRENT PACKAGE...OR BEFORE THUNDERSTORMS ARRIVE. TIMING HAS THE
BULK OF CONVECTION OVER THE GREATER HOUSTON TERMINALS DURING THE
16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH AN EMBEDDED
STORM BOOK-ENDING THOSE TIMES. PRECIP BEGINNING TO FILL IN NICELY
AHEAD OF ONE-OF-TWO MAIN SQUALL LINES MOVING NE FROM SOUTH CENTRAL
TEXAS. THIS 50 KT LOW LEVEL JET AND AMPLE INFLOW INTO THE APPROACHING
MID-SURFACE LOW (NEAR KSAT) WILL AID IN KEEPING THE MAJORITY OF
THE DECKS AT IFR OR MVFR LEVELS...MORNING 20-25 SUSTAINED WINDS.
LINGERING -SHRA THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP
AROUND -RA THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER
OF PERIOD UNDER WESTERLY FLOW. 31
PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 48 60 42 63 / 100 30 30 10 10
HOUSTON (IAH) 72 52 63 45 65 / 100 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 100 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1001 AM CST WED JAN 25 2012
.DISCUSSION...
LINE OF STRONG/SEVERE THUNDERSTORMS MAKING PROGRESS MOVING EASTWARD
ACROSS SOUTHEAST TEXAS THIS MORNING WITH A TORNADO WATCH IN EFFECT
UNTIL 11 AM. NORTHERN HALF OF THE LINE (ROUGHLY NORTH OF I-10) IS
MOVING FASTER THAN THE SOUTHERN HALF OF THE LINE. WE WILL PROBABLY
BE ISSUING ADDITIONAL FLOOD ADVISORIES TO COVER THE POTENTIAL FOR
WIDESPREAD 1 TO 3 INCH RAINFALL TOTALS ACROSS THE SOUTHERN HALF OF
THIS STORM COMPLEX...AND THIS AREA WILL ALSO BE CLOSELY MONITORED FOR
THE POTENTIAL FOR SEVERE STORM DEVELOPMENT. HIGHER RAINFALL TOTALS
CANNOT BE RULED OUT.
UPDATED THE MORNING FORECAST WITH HIGHER RAIN CHANCES EAST AND COOLER
TEMPERATURES WEST. 42
&&
.PREV DISCUSSION... /ISSUED 738 AM CST WED JAN 25 2012/
UPDATE...
EXTENDED THE TORNADO WATCH INTO CHAMBERS...LIBERTY...SAN JACINTO
COUNTIES...AND GALVESTON BAY.
PREV DISCUSSION... /ISSUED 634 AM CST WED JAN 25 2012/
AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES (MVFR) AND WIND GUSTS THAT COULD EXCEED 35 KTS WITHIN STRONGEST
STORMS. IN THE MEANTIME...A 50 KT LL JET HAS SHORT TERM WIND SHEAR
IN CURRENT PACKAGE...OR BEFORE THUNDERSTORMS ARRIVE. TIMING HAS THE
BULK OF CONVECTION OVER THE GREATER HOUSTON TERMINALS DURING THE
16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH AN EMBEDDED
STORM BOOK-ENDING THOSE TIMES. PRECIP BEGINNING TO FILL IN NICELY
AHEAD OF ONE-OF-TWO MAIN SQUALL LINES MOVING NE FROM SOUTH CENTRAL
TEXAS. THIS 50 KT LOW LEVEL JET AND AMPLE INFLOW INTO THE APPROACHING
MID-SURFACE LOW (NEAR KSAT) WILL AID IN KEEPING THE MAJORITY OF
THE DECKS AT IFR OR MVFR LEVELS...MORNING 20-25 SUSTAINED WINDS.
LINGERING -SHRA THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP
AROUND -RA THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER
OF PERIOD UNDER WESTERLY FLOW. 31
PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 48 60 42 63 / 100 30 30 10 10
HOUSTON (IAH) 72 52 63 45 65 / 100 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 100 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
738 AM CST WED JAN 25 2012
.UPDATE...
EXTENDED THE TORNADO WATCH INTO CHAMBERS...LIBERTY...SAN JACINTO
COUNTIES...AND GALVESTON BAY.
&&
.PREV DISCUSSION... /ISSUED 634 AM CST WED JAN 25 2012/
AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES (MVFR) AND WIND GUSTS THAT COULD EXCEED 35 KTS WITHIN STRONGEST
STORMS. IN THE MEANTIME...A 50 KT LL JET HAS SHORT TERM WIND SHEAR
IN CURRENT PACKAGE...OR BEFORE THUNDERSTORMS ARRIVE. TIMING HAS THE
BULK OF CONVECTION OVER THE GREATER HOUSTON TERMINALS DURING THE
16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH AN EMBEDDED
STORM BOOK-ENDING THOSE TIMES. PRECIP BEGINNING TO FILL IN NICELY
AHEAD OF ONE-OF-TWO MAIN SQUALL LINES MOVING NE FROM SOUTH CENTRAL
TEXAS. THIS 50 KT LOW LEVEL JET AND AMPLE INFLOW INTO THE APPROACHING
MID-SURFACE LOW (NEAR KSAT) WILL AID IN KEEPING THE MAJORITY OF
THE DECKS AT IFR OR MVFR LEVELS...MORNING 20-25 SUSTAINED WINDS.
LINGERING -SHRA THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP
AROUND -RA THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER
OF PERIOD UNDER WESTERLY FLOW. 31
&&
PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
40
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
40
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 68 48 60 42 63 / 90 30 30 10 10
HOUSTON (IAH) 74 52 63 45 65 / 80 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 80 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
634 AM CST WED JAN 25 2012
AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES (MVFR) AND WIND GUSTS THAT COULD EXCEED 35 KTS WITHIN STRONGEST
STORMS. IN THE MEANTIME...A 50 KT LL JET HAS SHORT TERM WIND SHEAR
IN CURRENT PACKAGE...OR BEFORE THUNDERSTORMS ARRIVE. TIMING HAS THE
BULK OF CONVECTION OVER THE GREATER HOUSTON TERMINALS DURING THE
16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH AN EMBEDDED
STORM BOOK-ENDING THOSE TIMES. PRECIP BEGINNING TO FILL IN NICELY
AHEAD OF ONE-OF-TWO MAIN SQUALL LINES MOVING NE FROM SOUTH CENTRAL
TEXAS. THIS 50 KT LOW LEVEL JET AND AMPLE INFLOW INTO THE APPROACHING
MID-SURFACE LOW (NEAR KSAT) WILL AID IN KEEPING THE MAJORITY OF
THE DECKS AT IFR OR MVFR LEVELS...MORNING 20-25 SUSTAINED WINDS.
LINGERING -SHRA THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP
AROUND -RA THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER
OF PERIOD UNDER WESTERLY FLOW. 31
&&
PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
40
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
40
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 68 48 60 42 63 / 90 30 30 10 10
HOUSTON (IAH) 74 52 63 45 65 / 80 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 80 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
556 AM CST WED JAN 25 2012
.AVIATION...
MAIN AVIATION CONCERN WILL BE PERIODS OF HEAVY RAINFALL LIMITING
VISBIES INTO MVFR...WIND GUSTS THAT COULD EXCEED 30-35 KTS IN
STRONGEST STORMS. TIMING HAS THE BULK OF CONVECTION ACROSS METRO
DURING THE 16-20Z TIME FRAME...PERIODS OF SCATTERED SHOWERS WITH
AN EMBEDDED STORM BOOKENDING THOSE TIMES. PRECIP BEGINNING TO FILL
IN NICELY AHEAD OF ONE-OF-TWO MAIN SQUALL LINES PASSING OUT OF
SOUTH CENTRAL TEXAS THIS HOUR. A STRONG LOW LEVEL 45-50 KT JET AND
AMPLE INFLOW INTO THE APPROACHING MID-SURFACE LOW WILL AID IN KEEPING
THE MAJORITY OF THE DECKS AT IFR OR MVFR LEVELS. LINGERING -SHRA
THROUGH EVENING AS THE SURFACE LOW PASSES EAST...WRAP AROUND PRECIP
THROUGH LATE EVENING WITH OVERCAST DECKS THROUGH REMAINDER OF PERIOD
UNDER WESTERLY FLOW. 31
&&
.PREV DISCUSSION... /ISSUED 540 AM CST WED JAN 25 2012/
UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
40
PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
40
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 68 48 60 42 63 / 90 30 30 10 10
HOUSTON (IAH) 74 52 63 45 65 / 80 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 80 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
540 AM CST WED JAN 25 2012
.UPDATE...
UPDATE FOR STRONGER WINDS THAN EARLIER EXPECTED. SUSTAINED 20 TO
25 MPH HAVE DEVELOPED AHEAD OF THE STORMS MOVING TOWARD THE
WESTERN COUNTIES OF THE FORECAST AREA. 09Z RUC INITIALIZED WELL
WITH THE WINDS. THE STRONGER WINDS WILL DIMINISH BY MIDDAY. WIND
ADVISORY OUT THROUGH NOON.
40
&&
.PREV DISCUSSION... /ISSUED 422 AM CST WED JAN 25 2012/
DISCUSSION...
SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND ISOLATED
TORNADOES ARE A THREAT TODAY AS A STRONG STRONG STORM SYSTEM MOVES
ACROSS THE STATE. AT 3 AM THE UPPER LOW WAS LOCATED NEAR THE BIG
BEND AND A LARGE AREA OF THUNDERSTORMS WAS ALREADY AFFECTING THE
HILL COUNTRY. SE TX WAS UNDER THE STRONG INFLOW INTO THE SYSTEM
AND THE AIR MASS OVERHEAD WILL CONTINUE TO DESTABILIZE THIS
MORNING. THE STORM PREDICTION CENTER HAS ALREADY ISSUED A TORNADO
WATCH FOR MOST OF THE FORECAST AREA THROUGH 11 AM. AM EXPECTING
THAT THUNDERSTORMS WILL BEGIN AFFECTING LOCATIONS ALONG AND WEST
OF A LINE FROM COLLEGE STATION TO COLUMBUS BETWEEN 4 AND 6 AM...
AND THEN THE REMAINING AREAS ALONG AND WEST OF INTERSTATE 45 BY
MID MORNING.
THE MODELS WERE SIMILAR IN HOW THEY HANDLED THE MOVEMENT OF THE
UPPER LOW AND SURFACE FEATURES. EXPECT THE UPPER LOW TO SWING
EASTWARD THROUGH THE BIG BEND AREA THIS MORNING BEFORE HEADING TO
THE NORTHEAST THROUGH CENTRAL TEXAS TONIGHT. THE SURFACE FRONT
WILL BE RATHER SLOW TO MOVE EASTWARD AND LOCALLY HEAVY RAINFALL
IS LIKELY. THE PW/S REACH TO 1.7 INCHES...THE MAXIMUM HISTORICALLY
FOR THE END OF JANUARY AND ABOVE 2 STANDARD DEVIATIONS FROM
NORMAL. WILL WATCH THE MOVEMENT OF THE AREA OF THUNDERSTORMS
PUSHING EAST OF INTERSTATE 35 TO SEE IF ANY TRAINING OF STORMS
DEVELOP. MAY CONSIDER A FLOOD WATCH LATER THIS MORNING FOR THE
WESTERN COUNTIES OF THE FORECAST AREA IF THE LINE DOES NOT BEGIN
TO MOVE FASTER TO THE EAST.
THE COLD FRONT WILL BE A BIT SLOWER TO EXIT THROUGH SE TX THAN
EARLIER THOUGHT. THE CHANCES FOR STRONGER THUNDERSTORMS WITH
LOCALLY HEAVY RAINFALL WILL LINGER INTO THE MID AND LATE AFTERNOON
FOR LOCATIONS EAST OF INTERSTATE 45. WRAP AROUND MOISTURE WILL
THEN AFFECT THE FORECAST AREA TONIGHT AND THURSDAY AS THE UPPER
LOW MOVES ACROSS CENTRAL AND NORTH TEXAS.
FAIR AND COOLER WEATHER IS THEN IN STORE FOR THE REST OF THE
PERIOD. ANOTHER WEAK FRONT MOVES THROUGH ON SUNDAY BUT IT APPEARS
TO BE DRY FOR NOW AND WILL JUST REINFORCE THE COOL AND DRY AIR
OVERHEAD.
40
MARINE...
SMALL CRAFT ADVISORY IN EFFECT FOR ALL WATERS AS AN APPROACHING
STORM SYSTEM WILL INTRODUCE SOUTH-TO-NORTH MOVING BANDS OF HEAVY
RAINFALL AND STRONG THUNDERSTORMS WITHIN POCKETS OF RAIN SHOWERS.
ROBUST ONSHORE WINDS JUST UPSTREAM OF THE SURFACE TROUGH...WEAKENING
AS THE TROUGH NEARS AND PASSES EAST...THEN TURNING MODERATE OFFSHORE
LATTER THURSDAY WITHIN A TIGHT BACKSIDE GRADIENT. LOCAL BAY WATERS
WILL BE CHURNED UP WITH NEARSHORE 4 TO 5 FOOT SEA HEIGHTS...AS HIGH
AS 7 TO 8 FEET (WITH A SHORTER PERIOD) FURTHER OFFSHORE. IN THE
MEANTIME...MARINERS SHOULD CLOSELY MONITOR THE RADAR AND CURRENT
OBSERVATIONS THROUGH THE DAY AS WEATHER COULD QUICKLY TURN ROUGH
WITH ANY PASSING MARITIME STORM. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 68 48 60 42 63 / 90 30 30 10 10
HOUSTON (IAH) 74 52 63 45 65 / 80 40 20 10 10
GALVESTON (GLS) 72 55 64 50 62 / 80 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES:
AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...SAN
JACINTO...WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS SPOKANE WA
608 PM PST Thu Jan 26 2012
.SYNOPSIS...Relatively dry northwest flow will remain over the
region through the first half of the weekend. This flow pattern
will bring cooler than normal temperatures but no significant
chance of precipitation. Wetter and snowier weather will return by
Sunday with weak storms expected to impact the Inland Northwest
through much of next week.
&&
.DISCUSSION...Updated to add mention of blowing snow in some of
the lowland locations east of the cascade crest based on incoming
spotter reports...especially near Mazama and points east along
highway 20 into the Methow Valley. The resulting snow drifts are
causing some difficulties on the roads. /Pelatti
&&
.AVIATION...
00Z TAFS: VFR conditions expected at all sites through most of the
forecast period due to a drying air mass associated with a
transition to nw flow aloft. Any showers in this flow this evening
will generally remain fixed over extreme NE WA and N ID and away
from the TAF sites. The biggest question for this forecast is fog
and low cloud chances. NAM solution suggests low clouds will form
over the Palouse and nr KPUW late tonight and then drift N aft
12z...possibly impacting KGEG-KSFF-KCOE. Confidence is not great
about any of this occurring and impacting the airports...but of all
sites...it seems PUW has the best chance based on precipitation in
that area earlier today and some agreement with MOS and HRRR model
data. FX
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 16 31 19 34 25 37 / 0 0 10 10 10 30
Coeur d`Alene 19 33 18 34 24 39 / 0 10 10 10 20 40
Pullman 20 35 23 37 29 43 / 10 10 0 10 10 40
Lewiston 26 39 25 41 32 45 / 10 0 0 10 10 20
Colville 9 32 14 33 22 38 / 0 10 10 20 30 40
Sandpoint 18 34 18 33 23 37 / 10 10 20 20 30 40
Kellogg 20 31 19 32 23 37 / 40 10 10 10 20 50
Moses Lake 15 32 14 33 21 36 / 0 0 0 10 10 20
Wenatchee 20 31 16 33 21 36 / 0 0 0 10 10 20
Omak 11 28 11 31 19 36 / 0 0 10 10 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
254 PM PST Thu Jan 26 2012
.SYNOPSIS...Relatively dry northwest flow will remain over the
region through the first half of the weekend. This flow pattern
will bring cooler than normal temperatures but no significant
chance of precipitation. Wetter and snowier weather will return by
Sunday with weak storms expected to impact the Inland Northwest
through much of next week.
&&
.DISCUSSION...
tonight...Unstable northwest flow will prolong the threat of showers
at least through the first half of the night over the Idaho Panhandle
and near the Cascade Crest. Model soundings are consistent in
depicting a layer of elevated instability extending from the near
the surface to roughly 650 mbs over the central Idaho
Panhandle...with much shallower instability north of Sandpoint and
near the Cascades. The trend overnight will be to see increasing
stability and thus fewer showers. Most of the activity will only
contain light snow as the dendritic layer continues to dry through
the evening.
Aside from the threat of showers...the main weather story tonight
will be the cool overnight low temperatures. Skies will generally
clear over the entire forecast area...with nary any high or mid-
level clouds seen in the upstream flow (northwest). Winds will
also decouple and weaken quickly over night. These two ingredients
often lead to very chilly temperature especially when there is a
significant snow pack in place and late afternoon dewpoints are in
the teens. This is the certainly the case...especially over the
northern third of Washington...so single digit lows seem quite
plausible. Fog should be minimal initially...but the NAM model
does hint at shallow fog forming late over the valleys near the
Canadian border. There are also hints of a low cloud deck forming
over the Palouse late tonight and expanding northward into the
Spokane area around sunrise. fx
Friday through Monday: The region will get a well deserved
break in the wet weather Friday into Saturday courtesy of a ridge
of high pressure. This break will be short-lived as the next round
of precipitation arrives late Saturday lingering into Monday
associated with energy crossing the Pacific Basin nearing 150W
this afternoon. Models are in general agreement with the overall
pattern with the biggest differences noted with the strength of
the parent midlevel trough crossing the region Monday.
We start the period off on the eastern periphery of a building
upper-level ridge. The ridge axis will be centered along 130W
Friday aftn then shift inland crossing the Cascades late Saturday
afternoon. Dry, cooler northwest flow Friday aftn will gradually
switch to the w/sw. While we will be lacking moisture in the mid
and upper-levels however lingering boundary layer moisture from
fog and stratus over the lowlands will be lifted up the higher
terrain of northern mountains. Additionally, the tail end of a
warm front will clip the area. Consequently, we have maintained a
slight chance for light snow showers near the Canadian Border but
all other zones will experience dry conditions and seasonal
temperatures.
The ridge axis will shift east into western Montana Saturday night
and weak impulses will continue to track through southern BC.
This will continue to flatten midlevel flow and allow a rich
moisture fetch previously aimed into sw BC to lay into the region.
The combination of strong warm advection and increasing moisture
influx will lead to thickening clouds region-wide with light
stratiform pcpn materializing across the north and slowly
expanding southward through the day Sunday and Monday. Persistent
and breezy southwesterly flow at 85H will focus the heaviest
showers along the Cascade Crest, NE Mtns, and Northern ID
Panhandle with some rain shadowing in the lee of the Cascades for
much of Sunday. A short-wave trough and associated cold front will
push through Sunday night and Monday and this will bring the best
chance for pcpn in most valley locations along with deeper mixing
and threat for breezy winds. The combination of orographic flow
and lift along the frontal boundary will bring the potential for
moderate to heavy snow accumulations in the eastern mountains and
along the Cascade Crest. Pcpn amounts could also be fairly high
across portions of Eastern WA including the Palouse, Blue Mtns,
and even Spokane area pending which model you trust on the
strength of the incoming front. Needless to say, the moisture
content of the incoming air mass will be quite high and snow
levels are expected to climb near 4-5K ft near the WA/OR border
and 1500-2K Ft along the Canadian Border. This would indicate rain
as the dominate p-type south of highway 2 but I will not be
surprised for the possibility of mixed wintry pcpn along and north
of highway 2 as well as the lee of the Cascades and details will
become fine tuned in the coming days when confidence is higher on
thermal fields setting up Saturday night. Winter headlines appear
very possible for the mountain locations of N Idaho and possibly
NE WA. /sb
Monday night through Thursday...The large-scale weather pattern
will be progressive flow with a series of shortwave impulses
riding through the region. Model solution spread is considerable
concerning the timing of these impulses. Confidence is too low to
stray far from climo pops but it is reasonable to trend on the wet
side of climo for the higher elevations favorable to westerly
upslope flow. There is not a lot of evidence supporting any
particularly strong systems for the extended forecast period. The
12z GFS has a decent warm front prog`ed to affect the region
Wednesday night into Thursday while the ECMWF has a weaker system
directed to our south. Until model consensus improves,
temperatures will also remain close to seasonal averages. /Kelch
&&
.AVIATION...
00Z TAFS: VFR conditions expected at all sites through most of the
forecast period due to a drying air mass associated with a
transition to nw flow aloft. Any showers in this flow this evening
will generally remain fixed over extreme NE WA and N ID and away
from the TAF sites. The biggest question for this forecast is fog
and low cloud chances. NAM solution suggests low clouds will form
over the Palouse and nr KPUW late tonight and then drift N aft
12z...possibly impacting KGEG-KSFF-KCOE. Confidence is not great
about any of this occurring and impacting the airports...but of all
sites...it seems PUW has the best chance based on precipitation in
that area earlier today and some agreement with MOS and HRRR model
data. FX
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 16 31 19 34 25 37 / 0 0 10 10 10 30
Coeur d`Alene 19 33 18 34 24 39 / 0 10 10 10 20 40
Pullman 20 35 23 37 29 43 / 10 10 0 10 10 40
Lewiston 26 39 25 41 32 45 / 10 0 0 10 10 20
Colville 9 32 14 33 22 38 / 0 10 10 20 30 40
Sandpoint 18 34 18 33 23 37 / 10 10 20 20 30 40
Kellogg 20 31 19 32 23 37 / 40 10 10 10 20 50
Moses Lake 15 32 14 33 21 36 / 0 0 0 10 10 20
Wenatchee 20 31 16 33 21 36 / 0 0 0 10 10 20
Omak 11 28 11 31 19 36 / 0 0 10 10 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 AM CST WED JAN 25 2012
.SHORT TERM...TODAY THROUGH FRIDAY
318 AM CST WED JAN 25 2012
MAIN FORECAST CONCERNS INCLUDE SNOW CHANCES TODAY...AND THEN
TEMPERATURES THROUGH THE SHORT TERM.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID-LEVEL TROUGH
EXTENDING FROM EASTERN ND THROUGH NEBRASKA. ISENTROPIC LIFT AHEAD OF
THIS TROUGH WAS PRODUCING AREAS OF LIGHT SNOW ACROSS PORTIONS OF
SOUTHERN MN INTO WEST-CENTRAL AND NORTHWEST WI PER THE RADAR
MOSAIC/SURFACE OBSERVATIONS. MOST OF THIS WAS VERY LIGHT SNOW WITH
VISIBILITIES IN THE 7-10SM RANGE...BUT THERE WERE POCKETS OF 1-2SM
-SN WHERE THERE WAS MORE VIGOROUS SATURATION OF THE COLUMN.
OTHERWISE...WITH CLOUDS AND WEAK SOUTHERLY SURFACE FLOW...
TEMPERATURES AT 3 AM WERE IN THE UPPER TEENS TO LOWER 20S.
25.00Z NAM/GFS AS WELL AS THE 25.03Z SREF ALL IN GOOD AGREEMENT WITH
OVERALL UPPER LEVEL/SURFACE FEATURES THROUGH THE SHORT TERM.
FOR TODAY...MODELS CONTINUE TO SHOW ISENTROPIC LIFT THROUGH THIS
MORNING ALONG AND NORTH OF I-90 THROUGH THIS MORNING...THEN SHIFTS
NORTH OUT OF THE AREA BY THIS AFTERNOON AS THE MID-LEVEL TROUGH
BEGINS TO FILL/WEAKEN AS IT MOVES THROUGH. AS SUCH...WILL CONTINUE
-SN CHANCES MAINLY ALONG/NORTH OF I-90 THIS MORNING...THEN WILL GO
DRY THIS AFTERNOON. ANY SNOWFALL EXPECTED TO BE MINIMAL WITH PERHAPS
A TENTH OF AN INCH OR TWO TENTHS AT MOST. MOSTLY CLOUDY CONDITIONS
EXPECTED THROUGH THE REMAINDER OF THE DAY WITH PERHAPS SOME CLEARING
ACROSS THE SOUTH LATE IN THE AFTERNOON. OTHERWISE...AFTER A
RELATIVELY WARMER START THIS MORNING...HIGHS TODAY SHOULD TOP OF IN
THE LOWER 30S.
MILDER TEMPERATURES EXPECTED THROUGH THURSDAY IN WARM AIR ADVECTION
AHEAD OF A DEEP LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA.
NAM INDICATING 925MB TEMPERATURES WARMING TO 0-5C THROUGH MIDDAY
THURSDAY. A COLD FRONT WILL THEN BE MOVING INTO THE AREA BY
MIDDAY...BUT BULK OF THE COLD AIR ADVECTION LOOKS LIKE IT WILL
FOLLOW NORMAL MID-LATE AFTERNOON DIURNAL T-CURVE DOWNSWING. SO
EXPECTING HIGHS THROUGH ABOUT MIDDAY...THEN FALLING THROUGH THE
AFTERNOON. BOTTOM LINE...LOOKS LIKE HIGHS THURSDAY SHOULD TOP OFF IN
THE MID-UPPER 30S.
SKIES EXPECTED TO CLEAR THROUGH MIDNIGHT ACROSS THE AREA THROUGH
THURSDAY EVENING WITH JUST A BRIEF SHOT OF COLD AIR ADVECTION MAINLY
EAST OF THE MISSISSIPPI RIVER. AFTER 06Z THURSDAY...BUFKIT SOUNDINGS
SHOW INCREASING MID/HIGH LEVEL CLOUDS MOVING IN MAINLY WEST OF THE
MISSISSIPPI RIVER IN ADVANCE OF A WEAK MID-LEVEL TROUGH/SURFACE LOW
PRESSURE MOVING ACROSS THE NORTHERN PLAINS.
ON FRIDAY...WILL CONTINUE TO SEE THAT WEAK MID-LEVEL TROUGH/SURFACE
LOW RIPPLE SOUTHEAST ACROSS IA INTO NORTHERN IL. BUFKIT COMPARISONS
OF THE GFS/NAM SHOW DIFFERING OPINIONS ON DEGREE OF COLUMN
SATURATION. THE GFS AT THIS POINT IS A BIT DRIER IN THE LOWER LEVELS
WHEREAS THE NAM WANTS TO SATURATE/PRECIPITATE MAINLY ALONG AND SOUTH
OF I-94. FOR NOW WILL CARRY 30 POPS FOR THIS AREA.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
318 AM CST WED JAN 25 2012
25.00Z GFS/ECMWF BOTH SHOW COLD AIR ADVECTION WITH DEEPENING MID-
LEVEL TROUGH DROPPING INTO THE REGION FRIDAY NIGHT THROUGH SATURDAY
FOR A CHANCE OF -SN. HIGHS SATURDAY EXPECTED TO FALL BACK TO NEAR
NORMAL LEVELS IN THE MID/UPPER 20S. SURFACE RIDGE OF HIGH PRESSURE
SLIDES ACROSS THE AREA ON SUNDAY FOR MOSTLY SUNNY SKIES...BUT HIGHS
ONLY EXPECTED TO TOP OFF IN THE TEENS TO LOWER 20S. MODERATING
TEMPERATURES THEN EXPECTED MONDAY AS A WEAK LOW AND WARM FRONT PUSH
OUT OF THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGION.
ISENTROPIC LIFT AHEAD OF THE LOW AND WARM FRONT WILL PRODUCE A
SLIGHT CHANCE OF -SN. OTHERWISE...LOOKING FOR HIGHS PUSHING INTO THE
MID 20S TO LOWER 30S. ON TUESDAY...THE WARM FRONT LOOKS TO LINGER
ACROSS THE AREA FOR A CHANCE OF RAIN OR SNOW AS HIGHS TOP OFF IN THE
30S.
&&
.AVIATION...
520 AM CST WED JAN 25 2012
LIGHT SN ACROSS THE REGION IN RESPONSE TO AN UPPER LEVEL SHORTWAVE
TROUGH MOVING EAST ACROSS THE REGION. SATURATION IS A BIG ISSUE FOR
-SN CHANCES AND DRY AIR TO THE SOUTH PROGGED TO ADVANCE NORTH AS THE
MORNING WEARS ON. EXPECT AREAS OF -SN TO DIMINISH AS A RESULT...AND
CIGS SHOULD BE KEPT VFR AT KRST/KLSE. WILL KEEP ANY -SN OUT OF THE
TAFS.
SOUTH WINDS WILL BE ON THE INCREASE TONIGHT...AND SOME CONCERN THAT
THIS WILL ADVECT IN SOME LOWER SATURATION AND LOW CIGS. SNOW PACK TO
THE SOUTH...AND SNOW TEMPS...SUGGEST THAT A STRONG SOUTHERLY FETCH
COULD LEAD TO NEAR SFC SATURATION AND THE POTENTIAL FOR LOW STRATUS.
CONFIDENCE NOT HIGH ENOUGH TO ADD MENTION TO THE TAFS AT THIS
TIME...BUT THIS POTENTIAL WILL HAVE TO BE MONITORED.
ANOTHER SHORTWAVE TROUGH WILL SWEEP MORE CLOUDS INTO THE REGION BY
THU MORNING...BUT ANY CEILINGS LOOK TO BE VFR AT THIS TIME. WINDS
WILL STAY BLUSTERY AND POTENTIALLY GUSTY...ESPECIALLY IN A 06-18Z
THU TIME FRAME. LOOK FOR A SWING TO WEST/NORTHWEST THU MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
318 AM CST WED JAN 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... DAS
LONG TERM.... DAS
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 AM CST WED JAN 25 2012
.SHORT TERM...TODAY THROUGH FRIDAY
318 AM CST WED JAN 25 2012
MAIN FORECAST CONCERNS INCLUDE SNOW CHANCES TODAY...AND THEN
TEMPERATURES THROUGH THE SHORT TERM.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID-LEVEL TROUGH
EXTENDING FROM EASTERN ND THROUGH NEBRASKA. ISENTROPIC LIFT AHEAD OF
THIS TROUGH WAS PRODUCING AREAS OF LIGHT SNOW ACROSS PORTIONS OF
SOUTHERN MN INTO WEST-CENTRAL AND NORTHWEST WI PER THE RADAR
MOSAIC/SURFACE OBSERVATIONS. MOST OF THIS WAS VERY LIGHT SNOW WITH
VISIBILITIES IN THE 7-10SM RANGE...BUT THERE WERE POCKETS OF 1-2SM
-SN WHERE THERE WAS MORE VIGOROUS SATURATION OF THE COLUMN.
OTHERWISE...WITH CLOUDS AND WEAK SOUTHERLY SURFACE FLOW...
TEMPERATURES AT 3 AM WERE IN THE UPPER TEENS TO LOWER 20S.
25.00Z NAM/GFS AS WELL AS THE 25.03Z SREF ALL IN GOOD AGREEMENT WITH
OVERALL UPPER LEVEL/SURFACE FEATURES THROUGH THE SHORT TERM.
FOR TODAY...MODELS CONTINUE TO SHOW ISENTROPIC LIFT THROUGH THIS
MORNING ALONG AND NORTH OF I-90 THROUGH THIS MORNING...THEN SHIFTS
NORTH OUT OF THE AREA BY THIS AFTERNOON AS THE MID-LEVEL TROUGH
BEGINS TO FILL/WEAKEN AS IT MOVES THROUGH. AS SUCH...WILL CONTINUE
-SN CHANCES MAINLY ALONG/NORTH OF I-90 THIS MORNING...THEN WILL GO
DRY THIS AFTERNOON. ANY SNOWFALL EXPECTED TO BE MINIMAL WITH PERHAPS
A TENTH OF AN INCH OR TWO TENTHS AT MOST. MOSTLY CLOUDY CONDITIONS
EXPECTED THROUGH THE REMAINDER OF THE DAY WITH PERHAPS SOME CLEARING
ACROSS THE SOUTH LATE IN THE AFTERNOON. OTHERWISE...AFTER A RELATIVELY
WARMER START THIS MORNING...HIGHS TODAY SHOULD TOP OF IN THE LOWER
30S.
MILDER TEMPERATURES EXPECTED THROUGH THURSDAY IN WARM AIR ADVECTION
AHEAD OF A DEEP LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA.
NAM INDICATING 925MB TEMPERATURES WARMING TO 0-5C THROUGH MIDDAY
THURSDAY. A COLD FRONT WILL THEN BE MOVING INTO THE AREA BY
MIDDAY...BUT BULK OF THE COLD AIR ADVECTION LOOKS LIKE IT WILL
FOLLOW NORMAL MID-LATE AFTERNOON DIURNAL T-CURVE DOWNSWING. SO
EXPECTING HIGHS THROUGH ABOUT MIDDAY...THEN FALLING THROUGH THE
AFTERNOON. BOTTOM LINE...LOOKS LIKE HIGHS THURSDAY SHOULD TOP OFF IN
THE MID-UPPER 30S.
SKIES EXPECTED TO CLEAR THROUGH MIDNIGHT ACROSS THE AREA THROUGH
THURSDAY EVENING WITH JUST A BRIEF SHOT OF COLD AIR ADVECTION MAINLY
EAST OF THE MISSISSIPPI RIVER. AFTER 06Z THURSDAY...BUFKIT SOUNDINGS
SHOW INCREASING MID/HIGH LEVEL CLOUDS MOVING IN MAINLY WEST OF THE
MISSISSIPPI RIVER IN ADVANCE OF A WEAK MID-LEVEL TROUGH/SURFACE LOW
PRESSURE MOVING ACROSS THE NORTHERN PLAINS.
ON FRIDAY...WILL CONTINUE TO SEE THAT WEAK MID-LEVEL TROUGH/SURFACE
LOW RIPPLE SOUTHEAST ACROSS IA INTO NORTHERN IL. BUFKIT COMPARISONS
OF THE GFS/NAM SHOW DIFFERING OPINIONS ON DEGREE OF COLUMN
SATURATION. THE GFS AT THIS POINT IS A BIT DRIER IN THE LOWER LEVELS
WHEREAS THE NAM WANTS TO SATURATE/PRECIPITATE MAINLY ALONG AND SOUTH
OF I-94. FOR NOW WILL CARRY 30 POPS FOR THIS AREA.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
318 AM CST WED JAN 25 2012
25.00Z GFS/ECMWF BOTH SHOW COLD AIR ADVECTION WITH DEEPENING MID-
LEVEL TROUGH DROPPING INTO THE REGION FRIDAY NIGHT THROUGH SATURDAY
FOR A CHANCE OF -SN. HIGHS SATURDAY EXPECTED TO FALL BACK TO NEAR
NORMAL LEVELS IN THE MID/UPPER 20S. SURFACE RIDGE OF HIGH PRESSURE
SLIDES ACROSS THE AREA ON SUNDAY FOR MOSTLY SUNNY SKIES...BUT HIGHS
ONLY EXPECTED TO TOP OFF IN THE TEENS TO LOWER 20S. MODERATING
TEMPERATURES THEN EXPECTED MONDAY AS A WEAK LOW AND WARM FRONT PUSH
OUT OF THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGION.
ISENTROPIC LIFT AHEAD OF THE LOW AND WARM FRONT WILL PRODUCE A
SLIGHT CHANCE OF -SN. OTHERWISE...LOOKING FOR HIGHS PUSHING INTO THE
MID 20S TO LOWER 30S. ON TUESDAY...THE WARM FRONT LOOKS TO LINGER
ACROSS THE AREA FOR A CHANCE OF RAIN OR SNOW AS HIGHS TOP OFF IN THE
30S.
&&
.AVIATION...THROUGH 06Z THURSDAY
1126 PM CST TUE JAN 24 2012
MVFR/IFR STRATUS DECK THAT WAS OVER SOUTHERN MINNESOTA...NORTHERN
IOWA AND PORTIONS OF SOUTHWEST WISCONSIN HAS COMPLETELY
DISSIPATED...LIKELY DUE TO AN INFLUX OF LOW LEVEL DRY AIR FROM
SOUTHEAST IOWA. IN ADDITION...MUCH OF THE MVFR BR HAS DISSIPATED.
WITH THE LACK OF STRATUS AND 900-925MB WINDS PROMOTING DRY AIR TO
KEEP ADVECTING OUT OF EASTERN IOWA THROUGH THE DAY THURSDAY...HAVE
WENT WITH A MUCH MORE OPTIMISTIC TAF FORECAST FOR BOTH SITES. THIS
IS EVEN IN SPITE OF SOME PRECIPITATION OVER NORTHWEST IOWA AND
SOUTHWEST MINNESOTA POSSIBLY COMING ACROSS...THOUGH EVEN THIS
PRECIPITATION IS FALLING APART. KEPT A -SN MENTION IN THE TAFS FOR
THE MORNING IN CASE IT OCCURS...BUT NO RESTRICTION IN VISIBILITY.
IF SNOW DOES OCCUR...LITTLE IF ANY ACCUMULATION IS EXPECTED. TAF
FORECAST IS NOW VFR THROUGH 06Z PERIOD. ONLY OTHER ITEM OF NOTE IS
A COLD FRONT MOVING INTO WESTERN MINNESOTA AT 06Z THURSDAY. AN
INCREASING PRESSURE GRADIENT AHEAD OF THIS FRONT WILL HELP TO
INCREASE SOUTHERLY WINDS AT BOTH TAF SITES...ESPECIALLY KRST WHERE
UP TO 15 KT SUSTAINED SPEEDS ARE FORECAST. NO CONCERN FOR LOW
LEVEL WIND SHEAR AT THIS TIME...THOUGH THERE IS A CONCERN ABOUT
MOISTURE COMING UP WITH THE WINDS FOR THE EVENING. RIGHT NOW
THINK THE MIXING FROM THE WIND...WARMING AND MOISTURE WILL BALANCE
OUT SUCH THAT NO STRATUS OR BR OCCURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
318 AM CST WED JAN 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1126 PM CST TUE JAN 24 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
300 PM CST TUE JAN 24 2012
MAIN FORECAST CONCERN IS ON SNOW CHANCES LATE TONIGHT INTO WEDNESDAY
MORNING AND THE POSSIBILITY OF SOME MIXED PRECIPITATION...THEN
MAINLY CLOUDS AND TEMPERATURES.
18Z SURFACE ANALYSIS SHOWS HIGH PRESSURE EXTENDING FROM SOUTHERN
ILLINOIS...NORTHWARD INTO SOUTHERN AND CENTRAL MINNESOTA. ONE BAND
OF STATUS MOVED EAST OF THE AREA THIS MORNING...BUT VISIBLE
SATELLITE IMAGERY AND SURFACE REPORTS SHOW ANOTHER AREA OF STRATUS
OVER SOUTHEAST MINNESOTA AND NORTHERN IOWA AS THE MOISTURE IS
TRAPPED UNDER THE SUBSIDENCE INVERSION.
24.12Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. THERE ARE
SOME MINOR DIFFERENCES...ESPECIALLY IN THE LATER PERIODS WITH THE
STRENGTH OF THE 500MB LOW THAT MOVES ACROSS SOUTHERN CANADA.
DIFFERENCES SUBTLE ENOUGH TO USE A BLEND APPROACH. OVERALL...MAINLY
ZONAL LOW INITIALLY WILL SLOWLY TRANSITIONS TO A MORE NORTHWESTERLY
FLOW BY THURSDAY AND FRIDAY AS UPPER LOW TRANSLATES ACROSS
SOUTHERN CANADA.
IN THE NEAR TERM...ANY BREAK IN THE CLOUDS WILL BE SHORT LIVED
TONIGHT AS SHORTWAVE TROUGH CROSSES THE PLAINS. THIS WILL SPREAD
CLOUDS BACK INTO THE AREA THIS EVENING. MODELS HAVE BEEN
CONSISTENT IN A WEAK AREA OF ISENTROPIC LIFT ACROSS THE WEST AND
NORTH LATE TONIGHT/EARLY WEDNESDAY. VERY WEAK QG
CONVERGENCE...MAINLY ABOVE 700MB AFFECTS THE AREA WITH THE WAVE.
MODELS HAVE BEEN PAINTING SOME VERY LIGHT QPF FROM SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN. BUFKIT SOUNDINGS ALSO
SHOWING A 925MB-875MB WARM NOSE PUSHING INTO SOUTHEAST MINNESOTA
AFTER 09Z. NAM A BIT MORE AGGRESSIVE WITH +1 TO +2 CELSIUS
TEMPERATURES IN THE WARM LAYER...AND GFS CLOSER TO 0 TO +1
CELSIUS. HOWEVER..24.18Z RUC COOLS LAYER BEFORE PRECIPITATING AND
THUS KEEPS IT ALL SNOW. THIS COULD POSE A PRECIPITATION TYPE
PROBLEM...HOWEVER THE PRESENCE OF DRY AIR WILL LIKELY COOL COLUMN
ONCE PRECIPITATION BEGINS PER THE RUC...AND THUS HAVE LEFT IT ALL
SNOW. EVENING SHIFT WILL HAVE TO MONITOR THOUGH FOR THE
POSSIBILITY OF SOME SLEET WITH THE SNOW LATE TONIGHT. DID RAISE
PROBABILITIES A LITTLE TONIGHT...THINKING IT WILL BE MAINLY A NON
ACCUMULATING EVENT...SO ONLY WENT WITH CHANCE PROBABILITIES.
WEDNESDAY THROUGH THURSDAY LOOK QUIET WITH JUST SOME MID CLOUDS
FROM TIME TO TIME. WITH A STRONGER SOUTHWEST LOW LEVEL FLOW AND
925MB TEMPERATURES WARMING TO +1 TO +2 CELSIUS...TEMPERATURES LOOK
TO BE ON THE MILDER SIDE WITH READINGS BACK ABOVE NORMAL. WINDS DO
BECOME MORE WESTERLY THURSDAY AS A TROUGH ROTATES THROUGH THE
AREA...BUT LITTLE IN THE WAY OF COOLING BEHIND IT AND THUS EXPECT
TEMPERATURES TO REMAIN MILD. GIVEN THE SNOW COVER DID NOT GO AS
WARM AS GUIDANCE...BUT WILL SEE READINGS IN THE LOWER TO MIDDLE
30S EACH DAY AND MIDDLE 20S OVERNIGHT.
BY FRIDAY AND FRIDAY NIGHT...A SHORTWAVE ROTATES AROUND THE SOUTHERN
CANADA UPPER LOW WITH AN ASSOCIATED COLD FRONT. BOTH THE GFS AND
ECMWF IS SHOWING SOME WEAK FORCING ACROSS THE AREA AND DID GO WITH
SOME LOWER END SNOW PROBABILITIES.
.LONG TERM...SATURDAY THROUGH TUESDAY
300 PM CST TUE JAN 24 2012
LONGWAVE TROUGH GETS CARVED OUT OF THE FLOW AS 500MB LOW DEEPENS
ACROSS SOUTHERN CANADA SATURDAY AND SUNDAY. THIS WILL ALLOW COLDER
AIR TO FILTER INTO THE AREA...WITH TEMPERATURES FALLING BACK TO
BELOW NORMAL READINGS FOR A BRIEF PERIOD OF TIME. A SHORTWAVE
ROTATING THROUGH THE FLOW MAY BRING SOME LIGHT SNOW CHANCES IN AREAS
NORTH OF INTERSTATE 94 SATURDAY...WITH THE REMAINDER OF THE AREA
REMAINING DRY. TROUGH DOES BEGIN TO PUSH EAST SUNDAY...WITH HEIGHTS
BEGINNING TO RISE ON MONDAY AND TUESDAY. TEMPERATURES WILL MODERATE
MONDAY AND TUESDAY...WITH A DISTURBANCE RIDING DOWN THE FLOW
TUESDAY BRING A CHANCE OF RAIN OR SNOW...AS TEMPERATURES REBOUND
INTO THE MIDDLE 30S.
&&
.AVIATION...THROUGH 06Z THURSDAY
1126 PM CST TUE JAN 24 2012
MVFR/IFR STRATUS DECK THAT WAS OVER SOUTHERN MINNESOTA...NORTHERN
IOWA AND PORTIONS OF SOUTHWEST WISCONSIN HAS COMPLETELY
DISSIPATED...LIKELY DUE TO AN INFLUX OF LOW LEVEL DRY AIR FROM
SOUTHEAST IOWA. IN ADDITION...MUCH OF THE MVFR BR HAS DISSIPATED.
WITH THE LACK OF STRATUS AND 900-925MB WINDS PROMOTING DRY AIR TO
KEEP ADVECTING OUT OF EASTERN IOWA THROUGH THE DAY THURSDAY...HAVE
WENT WITH A MUCH MORE OPTOMISTIC TAF FORECAST FOR BOTH SITES. THIS
IS EVEN IN SPITE OF SOME PRECIPITATION OVER NORTHWEST IOWA AND
SOUTHWEST MINNESOTA POSSIBLY COMING ACROSS...THOUGH EVEN THIS
PRECIPITATION IS FALLING APART. KEPT A -SN MENTION IN THE TAFS FOR
THE MORNING IN CASE IT OCCURS...BUT NO RESTRICTION IN VISIBILITY.
IF SNOW DOES OCCUR...LITTLE IF ANY ACCUMULATION IS EXPECTED. TAF
FORECAST IS NOW VFR THROUGH 06Z PERIOD. ONLY OTHER ITEM OF NOTE IS
A COLD FRONT MOVING INTO WESTERN MINNESOTA AT 06Z THURSDAY. AN
INCREASING PRESSURE GRADIENT AHEAD OF THIS FRONT WILL HELP TO
INCREASE SOUTHERLY WINDS AT BOTH TAF SITES...ESPECIALLY KRST WHERE
UP TO 15 KT SUSTAINED SPEEDS ARE FORECAST. NO CONCERN FOR LOW
LEVEL WIND SHEAR AT THIS TIME...THOUGH THERE IS A CONCERN ABOUT
MOISTURE COMING UP WITH THE WINDS FOR THE EVENING. RIGHT NOW
THINK THE MIXING FROM THE WIND...WARMING AND MOISTURE WILL BALANCE
OUT SUCH THAT NO STRATUS OR BR OCCURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CST TUE JAN 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
333 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* LOW CEILINGS GRADUALLY DEPARTING FROM NORTHWEST TO SOUTHEAST BY
OR SOON AFTER DAYBREAK.
* LOW VISIBILITY GRADUALLY IMPROVING.
* CHANCES FOR SNOW FRIDAY EVENING/NIGHT.
//DISCUSSION...UPDATED 06Z...
A SLOW MOVING COLD FRONT IS MOVING ACROSS THE MISSISSIPPI RIVER THIS
EVENING WITH CONDITIONS QUICKLY IMPROVING TO VFR BEHIND THE FRONT.
AHEAD OF THE FRONT...WIDESPREAD IFR/LIFR CONDITIONS PERSIST MAINLY
DUE TO LOW CIGS...WITH VARIABLE VSBY. VSBY SHOULD SHOW A GRADUAL
IMPROVING TREND OVER NEXT COUPLE HOURS AS WIND SPEEDS PICK UP
AHEAD OF THE FRONT TONIGHT...BUT CIGS WILL HOLD STEADY OR MAY FALL
SOME AS WEAK PRESSURE FALLS CONTINUE TO OVERSPREAD THE AREA. SKIES
SHOULD QUICKLY CLEAR IN THE EARLY MORNING HOURS...~06Z AT RFD AND
09-10Z FOR THE CHICAGO AREA TERMINALS...AS ANTICYCLONIC FLOW
MOVES ACROSS THE REGION BEHIND THE COLD FRONT.
MOST OF FRIDAY WILL HAVE RELATIVELY QUIET WEATHER CONDITIONS WITH
WESTERLY WINDS GRADUALLY BACKING TO THE SOUTHWEST THROUGH THE DAY AS
ANOTHER CLIPPER SYSTEM PUSHES EAST ACROSS THE NORTHERN PLAINS. THIS
SYSTEM WILL BEGIN TO AFFECT THE ROCKFORD/CHICAGO TERMINALS DURING
THE EVENING HOURS AS CIGS BEGIN TO COME DOWN AND SNOWFALL STARTING
LATE IN THE EVENING. EXPECT LIGHT ACCUMULATIONS WITH THIS SYSTEM...
AN INCH OR TWO...WITH IFR OR LOW END MVFR CONDITIONS RETURNING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE IN EXACT DEPARTURE TIME OF MVFR CLOUDS...BUT
HIGH CONFIDENCE THEY WILL BE OUT OF THE AREA BY 13Z.
* MEDIUM CONFIDENCE IN VISIBILITY REMAINING 5SM OR HIGHER THE
REMAINDER OF THE NIGHT.
* MEDIUM CONFIDENCE ON SNOW TIMING FRIDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...MVFR POSSIBLE. GUSTS TO AROUND 30KT POSSIBLE.
SUNDAY...SLIGHT CHANCE OF SNOW...ELSE VFR.
MONDAY...VFR.
TUESDAY...MVFR WITH CHANCE OF RAIN.
WEDNESDAY...MVFR.
BMD/MTF
&&
.MARINE...
245 PM CST
RATHER BENIGN WEATHER FOR THIS AFTERNOON ACROSS LAKE
MICHIGAN...WITH MINIMAL WIND. ACROSS THE FAR NORTHERN TIER OF LAKE
MICHIGAN THE PRESSURE GRADIENT WAS SLIGHTLY STRONGER...RESULTING
IN WINDS BETWEEN 10 TO 20 KT. FURTHER SOUTH OVER THE SOUTHERN
THIRD OF THE LAKE...WINDS HAVE REMAINED LGT AND VRB LESS THAN
10KT. BASED ON LATEST HI-RES GUIDANCE...IT APPEARS WINDS WILL
CONTINUE TO BE LGT AND VRB THRU MIDNIGHT. MEANWHILE TWO LOW
PRESSURE SYSTEMS WILL BEGIN TO INFLUENCE THE WEATHER FOR LAKE
MICHIGAN. ONE SYSTEM CURRENTLY OVER SOUTHERN MANITOBA...WILL
DEEPEN AND LIFT NORTHEAST TOWARDS HUDSON BAY FRIDAY EVENING/EARLY
SATURDAY. WHILE A SOUTHERN STREAM LOW PRESSURE SYSTEM WILL DEVELOP
OVER THE TENNESSEE VALLEY...AND IS EXPECTED TO STRENGTHEN AND
LIFT NORTHEAST TOWARDS THE EASTERN GREAT LAKES REGION SATURDAY. THE
LOW PRESSURE OVER HUDSON BAY WILL HAVE A TRAILING FRONTAL BOUNDARY
THAT WILL PUSH EAST ACROSS LAKE MICHIGAN SATURDAY...WITH AN
INCREASING PRESSURE GRADIENT BEHIND IT. LATEST GUIDANCE HAS
CONTINUED TO TREND UPWARD THAT BY SATURDAY MIDDAY/AFTERNOON
OCCASIONAL GALE FORCE GUSTS WILL BE POSSIBLE TO 35KT. AT THIS TIME
HAVE OPTED TO REFRAIN FROM HOISTING ANY HEADLINES...AS CURRENTLY
ONLY COMING UP WITH MARGINAL CRITERIA.
A LULL IN THE WEATHER WILL OCCUR FOR LATE SAT EVE/EARLY SUN...BEFORE
YET ANOTHER LOW PRESSURE IS PROGGED TO DEVELOP OVER THE DAKOTAS AND
APPROACH THE WESTERN GREAT LAKES MIDDAY SUN. THEN HIGH PRESSURE WILL
RELAX THE GRADIENT FOR SUN NGT INTO EARLY MON...BEFORE THE ACTIVE
PATTERN CONTINUES EARLY NEXT WEEK.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ745...7 AM FRIDAY TO 2 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
208 PM EST THU JAN 26 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
PRECIPITATION WILL COME TO AN END TONIGHT AS LOW PRESSURE AND A
FRONTAL BOUNDARY MOVE EAST AWAY FROM THE OHIO VALLEY. AFTER A DRY
DAY FRIDAY...A QUICK MOVING ALBERTA CLIPPER WILL TRACK THROUGH THE
LOWER GREAT LAKES FRIDAY NIGHT WITH THE CHANCE FOR LIGHT SNOW FOR
CENTRAL INDIANA. AN ADDITIONAL CLIPPER MAY BRING FLURRIES OR LIGHT
SNOW AGAIN FOR SUNDAY MORNING. DRY WEATHER RETURNS TO END THE
WEEKEND AS HIGH PRESSURE SPREADS ACROSS THE AREA. TEMPERATURES WILL
WARM FOR EARLY NEXT WEEK WITH THE NEXT CHANCE FOR RAIN COMING
TUESDAY AND WEDNESDAY AS A FRONT MOVES THROUGH THE OHIO VALLEY.
&&
.NEAR TERM /REST OF TONIGHT/...
MAIN ADJUSTMENTS OVERNIGHT WILL BE TO SLOW DOWN ENDING OF
PRECIPITATION A LITTLE...DOWN PLAY SNOW AND ADD PATCHY FOG TO MOST
AREAS BASED ON CURRENT CONDITIONS UPSTREAM. RADAR AT 0230Z STILL
SHOWS AN EXTENSIVE AREA OF LIGHT RAIN SHOWERS ACROSS MOST OF OUR
FORECAST AREA AND RUC STILL SHOWS ACCUMULATIONS OVER MOST OF OUR
AREA THROUGH 09Z AND ACROSS THE EAST HALF THROUGH 12Z.
SO FAR NO AREAS OF SNOW HAVE DEVELOPED YET UPSTREAM AND RUC AND 18Z
GFS HAVE BACKED OFF CONSIDERABLY ON SNOWFALL LATE TONIGHT. 1000-850
MB THICKNESSES DROP BELOW 1300 METERS ALL BUT FAR SOUTHEAST BY 12Z.
BUT MOST OF THIS HAPPENS BETWEEN 09Z-12Z. WITH TEMPERATURES AND LOW
LEVEL THICKNESS MORE IFFY WILL MENTION A MIXTURE ALL BUT FAR SOUTH
AND SOUTHEAST LATE TONIGHT.
THERE HAVE BEEN AREAS OF FOG ACROSS CENTRAL ILLINOIS AND WILL ADD
MENTION OF PATCHY FOG MOST AREAS LATER TONIGHT. BUT WITH WINDS
INCREASING OVERNIGHT...I DO NOT EXPECT FOG TO BE A SIGNIFICANT
CONCERN.
AS FAR AS TEMPERATURES ARE CONCERNED...WILL RAISE LOWS A LITTLE MOST
AREAS OVERNIGHT DUE TO CLOUDS AND MILD TEMPERATURES UPSTREAM.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
SLOWED DOWN CLEARING A LITTLE ON FRIDAY AS SATELLITE SHOWS CLOUDS
EXTENDING BACK INTO EASTERN IOWA. OTHERWISE NO OTHER CHANGES MADE TO
GRIDS AFTER TONIGHT. PREVIOUS SHORT TERM DISCUSSION FOLLOWS...
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR ANOTHER QUICK SHOT OF
LIGHT SNOW FRIDAY NIGHT/EARLY SATURDAY AS A CLIPPER SYSTEM SWINGS
THROUGH THE LOWER GREAT LAKES.
FIRST CHALLENGE FOR FRIDAY FOCUSES ON THE CLOUD COVER WHICH APPEARS
INCREASINGLY LIKELY TO LINGER WELL INTO THE MORNING...ESPECIALLY
OVER THE EASTERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS SHOWING
A LEFTOVER INVERSION PRESENT WITH MOISTURE TRAPPED BENEATH IT. HAVE
THEREFORE BUMPED UP CLOUD COVER THROUGH MIDDAY...WITH DIMINISHING
LOW CLOUDS THEREAFTER AS THE INVERSION RELAXES. SUNSHINE THOUGH MAY
BE BRIEF AS MID AND HIGH LEVEL CLOUDS AHEAD OF THE APPROACHING
CLIPPER WILL ALREADY BE SPREADING INTO THE REGION FROM THE WEST BY
THE AFTERNOON THICKENING UP BY EARLY EVENING.
MODEL GUIDANCE HAS COME IN WITH A SHARPER CLIPPER SYSTEM FOR FRIDAY
NIGHT AND ALTHOUGH THE BULK OF THE DEEPER FORCING WILL REMAIN
CONFINED TO THE NORTH OF THE REGION CLOSER TO THE TRACK OF THE
LOW...SYSTEM WILL HAVE A GREATER IMPACT ON CENTRAL INDIANA AND
PARTICULARLY OVER THE NORTHERN HALF OF THE FORECAST AREA LATE FRIDAY
NIGHT. SYSTEM APPEARS TO BE A BIT STRONGER THAN PREVIOUS RUNS
INDICATED AND THERE IS MORE AMPLE MOISTURE AVAILABLE AS MID LEVEL
ENERGY DIVES OUT OF THE NORTHERN PLAINS AND HELPS AMPLIFY THE
SHORTWAVE ALOFT. DIV Q VALUES ALSO APPEAR QUITE FAVORABLE FOR A
SEVERAL HOUR PERIOD OF LIGHT TO OCCASIONALLY MODERATE SNOWFALL TO
ENCOMPASS THE NORTHERN HALF OF THE FORECAST AREA AS THE CLIPPER
PASSES THROUGH THE LOWER GREAT LAKES.
OTHER THAN A FEW FLURRIES...ANTICIPATE MUCH OF THE FORECAST AREA
REMAINS DRY UNTIL LATE EVENING AS LOWER LEVELS MOISTEN UP AND
SATURATE. AREA OF SNOW WILL THEN PROGRESS ACROSS THE FORECAST AREA
FOR THE REST OF THE NIGHT THROUGH A BOUT 12Z SATURDAY. TEMPS WILL
REMAIN NEAR IF NOT JUST ABOVE FREEZING FRIDAY EVENING AND INTO THE
OVERNIGHT BEFORE FALLING BACK INTO THE UPPER 20S/LOWER 30S WITH THE
ONSET OF SNOWFALL. GROWING CONFIDENCE IN LIGHT ACCUMULATIONS FOR
LOCATIONS NORTH OF A TERRE HAUTE-BLOOMINGTON-RUSHVILLE LINE RANGING
FROM A FEW TENTHS NEAR THOSE CITIES TO AROUND AN INCH ALONG THE I-70
CORRIDOR AND INCLUDING THE INDY METRO. OVER NORTHERN FORECAST AREA
WHERE FORCING ALOFT IS MORE ABUNDANT...FEEL 1.5 TO 2 INCHES MAY BE
ACHIEVABLE BY SATURDAY MORNING. OVER FAR SOUTHERN COUNTIES...LOWER
CONFIDENCE IN ANY SNOW ACCUMULATIONS AS BOUNDARY LAYER CONDITIONS
WILL BE MARGINAL TO SUPPORT AT BEST AND MAY SEE RA/SN MIX FOR THE
DURATION OF THE EVENT. WILL BE ISSUING AN SPS TO FURTHER HIGHLIGHT
SNOW POTENTIAL WITH THIS SYSTEM.
MUCH DRIER AIR AND A SHOT OF SUBSIDENCE ALOFT WILL SERVE TO DRY OUT
THE REGION QUICKLY SATURDAY MORNING...SETTING THE STAGE FOR A BREEZY
CHILLY DAY. STRONG HIGH PRESSURE WILL DRIFT BY TO THE SOUTH OF THE
REGION THROUGH THE COURSE OF THE DAY AND EVENING...WITH CLOUDS ONCE
AGAIN INCREASING LATE SATURDAY NIGHT AS ANOTHER CLIPPER MOVES INTO
THE WESTERN GREAT LAKES. WITH MODEL SOUNDINGS INDICATING AN
ABUNDANCE OF DRY AIR IN THE LOWER LEVELS SATURDAY NIGHT...ONLY
ANTICIPATING A FEW FLURRIES NORTH OF I-70 AT THIS TIME PRIOR TO
DAYBREAK SUNDAY.
TEMPS...WITH THE ANTICIPATED LATER DEPARTURE OF THE LOW CLOUDS
FRIDAY...LOWERED HIGHS BY A FEW DEGREES FROM PREVIOUS FORECAST. WENT
ABOVE GUIDANCE FOR LOWS FRIDAY NIGHT...THEN UNDERCUT BY SEVERAL
DEGREES SATURDAY AS COLD ADVECTION WILL KEEP TEMPS FROM RISING
MORE THAN 5 TO 8 DEGREES FROM MORNING LOWS. NEAR GUIDANCE ON LOWS
SATURDAY NIGHT FALLING INTO THE LOWER AND MID 20S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LONG RANGE MODELS HAVING SOME TIMING DIFFERENCES WITH SYNOPTIC
DETAILS AS WELL AS QPF...SO DID NOT FEEL COMFORTABLE CHANGING THE
CENTRAL REGION EXPENTED. ONE FRONTAL SYSTEM IS EXPECTED TO BRING A
CHANCE OF RAIN IN BY TUESDAY AND LINGER INTO OUR SOUTHEAST ON
WEDNESDAY MORNING. THEN...ANOTHER SYSTEM WILL BRING RAIN CHANCES
INTO THE SOUTHWEST WEDNESDAY NIGHT AND ACROSS ALL OF CENTRAL INDIANA
THURSDAY. COULD SEE A MIX OF RAIN AND SNOW OVERNIGHT WEDNESDAY
NIGHT...OTHERWISE...MILD TREND TO CONTINUE AS HAS BEEN THE CASE MOST
OF THE WINTER WITH QUASI-ZONAL FLOW ALOFT KEEPING THE COLDER
CANADIAN AIR NORTH OF THE OHIO VALLEY. DAYTIME HIGHS IN THE 40S
ANTICIPATED WITH 50S ACROSS PARTS OF SOUTH CENTRAL INDIANA TUESDAY
THROUGH WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR 270600Z KIND TAF ISSUANCE/...
IFR CEILINGS AT THE SITES WITH SOME RAIN STILL LINGERING OVER KBMG
AND KIND THAT WILL MOVE OUT BY 8Z IF NOT BEFORE. AT KHUF AND KLAF
PRECIPITATION SHOULD BE EAST OF THE SITES BY ISSUANCE TIME WITH THE
POSSIBLE EXCEPTION OF SOME DRIZZLE AT KHUF. WHILE GUIDANCE DOESN/T
INDICATE THIS...UPSTREAM OBS SHOW THAT VISIBILITIES COULD DROP ONCE
THE PRECIPITATION MOVES OUT. WILL PROBABLY KEEP THEM AT IFR LEVELS
UNTIL DAYBREAK. CEILINGS WILL STAY IFR OR DROP TO LIFR THROUGH THE
NIGHT. SHORTLY AFTER DAYBREAK THEY SHOULD RAISE TO MVFR AND THEN VFR
AT KLAF AND KHUF. KBMG AND KIND WILL LINGER IN THE LOW CLOUDS UNTIL
MIDDAY WITH THE INVERSION TAKING LONGER TO MIX OUT THERE. AFTER 18Z
THE SITES SHOULD BE VFR. IN THE EVENING A CLIPPER SYSTEM WILL
APPROACH THAT SHOULD BRING SNOW IN NEAR THE END OF THE PERIOD. THE
SOUTHWARD EXTENT OF THIS IS FAIRLY UNCERTAIN SO WILL LEAVE OUT OF
KBMG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN/JH
LONG TERM....MK
AVIATION...CP
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
312 AM CST FRI JAN 27 2012
.SYNOPSIS...
06Z SFC ANALYSIS HAS A STORM SYSTEM OVER THE EASTERN GREAT LAKES
MOVING INTO NEW ENGLAND. WEAK LOWS WERE LOCATED NEAR KBIS AND
KPHP. A WARM FRONT RAN FROM THE KPHP LOW TO NEAR KYKN AND THEN
SOUTH INTO EASTERN NEBRASKA. DEW POINTS WERE GENERALLY IN THE 20S
AND 30S ACROSS THE MIDWEST WITH A POCKET OF TEENS IN THE PLAINS.
SATELLITE TRENDS SHOW HIGH CLOUDS MOVING EAST TOWARD THE
MISSISSIPPI RIVER WITH MID AND SOME LOW CLOUDS IN THE PLAINS.
RADAR HAS VERY LIGHT PRECIPITATION OCCURRING IN THE CENTRAL AND
NORTHERN PLAINS.
&&
.SHORT TERM...TODAY AND TONIGHT...
THE KEY TO EVERYTHING LATER TODAY AND TONIGHT WILL BE WHEN DOES
SATURATION OCCUR. VERIFICATION OF THE MODELS THROUGH 06Z SHOW THEY
ARE WAY OVERDONE ON THE AMOUNT OF QPF. ADDITIONALLY...THEY ALL
INITIALIZED TOO MOIST IN THE LOW LEVELS AND HAD THE STRENGTH OF THE
PLAINS SFC RIDGE TOO STRONG. ALL THIS PLAYS SIGNIFICANTLY INTO
PRECIPITATION AMOUNTS IN THE NEXT 24 HRS.
OVERALL FORCING AND 850-700MB CONDENSATION PRESSURE DEFICITS FROM
THE RUC HAVE BEEN QUITE USEFUL IN DEPICTING WHERE PRECIPITATION
HAS BEEN OCCURRING IN THE PLAINS SO FAR. HOWEVER...IT TOO IS A BIT
OVERLY MOIST ON ITS INITIALIZATION AT 06Z.
THE MORNING HOURS WILL BE DRY WITH INCREASING CLOUDS. DURING THIS
TIME TEMPERATURES WILL RESPOND REASONABLE WELL TO THE WAA THAT
WILL BE OCCURRING AND ALLOW TEMPERATURES TO GET ABOVE NORMAL.
CAREFUL EXTRAPOLATION OF THE 12 HR RUC FCST SUGGESTS PRECIPITATION
ADVECTING OR DEVELOPING ROUGHLY WEST OF A DUBUQUE TO KEOKUK LINE
DURING THE FIRST HALF OF THE AFTERNOON. FCST SOUNDINGS FROM THE
RUC AND OTHER MODELS SUGGEST THAT MUCH OF THE FORCING WILL GO INTO
SATURATION. THE WARM TEMPERATURES INDICATE THAT THE PRECIPITATION
SHOULD INITIALLY START OUT AS RAIN. HOWEVER...EVAPORATIVE COOLING
WILL QUICKLY DROP THE LOWER ATMOSPHERE BELOW FREEZING. SO THE
PRECIPITATION WILL START OUT AS RAIN AND QUICKLY CHANGE TO SNOW
WITH A BRIEF PERIOD OF A MIX.
BY 00Z...6 PM...A WAA WING OF PRECIPITATION SHOULD COVER ALL BUT
THE FAR EASTERN REACHES OF THE CWFA. SNOW AMOUNTS BY EARLY EVENING
WILL RANGE FROM ZERO TO A DUSTING.
BASED ON THE OVERALL MOVEMENT OF THE FORCING...PRECIPITATION
SHOULD LAST ABOUT 6-9 HRS AT ANY ONE LOCATION ONCE IT BEGINS.
PRECIPITATION SHOULD BE WIDESPREAD ACROSS THE CWFA DURING THE
EARLY EVENING WITH IT ENDING FROM WEST TO EAST AFTER 9 PM.
PRECIPITATION SHOULD LINGER PAST MIDNIGHT OVER ROUGHLY THE EASTERN
HALF OF THE CWFA BEFORE ENDING BY SUNRISE SATURDAY.
OVERALL SNOW AMOUNTS FOR THIS EVENT SHOULD RANGE FROM A DUSTING TO
JUST OVER ONE HALF INCH.
..08..
.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
NORTHWEST FLOW PATTERN WILL DOMINATE INTO MON. CLIPPER SYSTEM TO PASS
MAINLY TO OUR NORTH SAT NGT WITH SMALL CHC OF -SN WITH WARM
ADVECTION WING FAR N/NE COUNTIES. BETTER CHCS WILL RESIDE
FARTHER NORTH ACROSS PORTIONS OF MN AND WI ALONG AND LEFT OF THE
TRACK IN THE COLDER AIR. AS IT PASSES TO OUR N/E SAT NGT IT WILL SEND
COLD FRONT DOWN THROUGH REGION RESULTING IN COLDER TEMPS (NEAR TO
A LITTLE BELOW NORMAL) ON SUNDAY. NEXT WEAK CLIPPER SYSTEM
AND ATTENDANT WARM ADVECTION WING LOOKS TO PASS WELL NORTH OF REGION
SUN NGT INTO MON. STRENGTHENING SOUTHERLY SFC FLOW WILL BRING WELL
ABOVE NORMALS TEMPS BACK INTO REGION. HAVE BUMPED UP HIGHS SEVERAL
DEGS ON MON... BUT IF 00Z GFS AND HI-RES ECMWF VERIFY ON MIXING DEPTH
AND THERMAL FIELDS THEN WOULD NEED TO RAISE FURTHER WITH BOTH
SUPPORTIVE OF M/U 40S IN THE NORTH TO AROUND 57F IN THE FAR SOUTH.
TUE-THU... ZONAL FLOW LOOKS TO DOMINATE ACROSS MUCH OF THE CONUS WITH
TEMPS ABOVE NORMAL IN MP AIRMASS. MODELS STILL VARY ON EVOLUTION
OF PACIFIC SHORTWAVE ON TUE WITH THE ECMWF AND GEM MORE PROGRESSIVE
AND NORTHERLY WHILE THE GFS AND UKMET ARE MUCH SLOWER AND MORE
SOUTHERLY. DPROG/DT OF GFS SHOWS CONSIDERABLE RUN TO RUN VARIANCE WHILE
ECMWF MORE STABLE... AND THUS FAVORED. LOW LEVEL MOISTURE LOOKS
FAIRLY SHALLOW AND TRANSPORT VECTORS VEER IN TIME ON TUE SHUNTING
BETTER LOW LEVEL MOISTURE TO OUR S/E. HAVE THEREFORE TRIMMED BACK POPS
TO MOSTLY SLIGHT CHC. PATTERN LOOKS TO SHIFT BACK TO HIGHLY AMPLIFIED
ONE BY LATE WEEK INTO NEXT WEEKEND WITH RETURN OF COLDER AIR. DURING
THIS TRANSITION THERE WILL BE AT LEAST A COUPLE OF PCPN CHCS (RAIN/SNOW)
THU-SAT. ..05..
&&
.PREV DISCUSSION... /ISSUED 1149 PM CST THU JAN 26 2012/
AVIATION...
COLD FRONTAL PASSAGE THIS AFTERNOON BRINGING DRIER AIR INTO THE
AREA WITH ALL TERMINALS VFR. CLEAR SKIES AND SUBSIDENCE TO PERSIST
UNTIL DAYBREAK. CLEAR SKIES AND VISIBILITY 7+ MILES TO CONTINUE
UNTIL 15Z FRIDAY WITH LIGHT NW WINDS OF 5-10 MPH. INCREASING HIGH
CLOUDS AOA 10K AGL AFTER 15Z WITH CIGS DOWN TO ~6K AGL WITH SNOW
SHOWERS AFTER 26/20Z ALL TERMINALS. SEVERAL HOURS OF MVFR TO
HIGHER END IFR CONDITIONS POSSIBLE UNTIL 27/06Z WITH LIGHT SNOW.
.NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
324 AM CST FRI JAN 27 2012
.SYNOPSIS...
IN APPLYING THE FORECAST FUNNEL, ONE WOULD START WITH THE 27.00Z 300
HPA SYNOPTIC MAP. A 100 KT JET EXTENDED FROM KMFR TO KLBF. THIS JET
WAS WELL UPSTREAM OF A HIGHLY AMPLIFIED MERIDIONAL TROUGH AXIS THAT
EXTENDED FROM ONTARIO INTO THE GULF OF MEXICO. A FASTER 135 TO 140 KT
JET LOCATED EAST OF THIS TROUGH AXIS ACROSS THE EASTERN UNITED STATES.
AT 500 HPA, A SHORTWAVE TROUGH WAS MOVING ACROSS THE NORTHERN ROCKIES.
THIS UPPER LEVEL FEATURE WAS USHERING IN A SURFACE COLD FRONT ACROSS
THE NORTHERN PLAINS AND INTO WYOMING. NOTHING TOO OUT OF THE ORDINARY WAS
OBSERVED AT 700 AND 850 HPA ACROSS THE CENTRAL PLAINS EXCEPT A DRY THERMODYNAMIC
PROFILE. -SUGDEN
&&
.DISCUSSION...
DAYS 1-2...
TODAY:
FORECAST SOUNDINGS FROM THE 27.00Z GFS AND 27.00Z NAM BOTH AGREE ON
RAPID SATURATION BETWEEN 600 AND 400 HPA IN ASSOCIATION WITH MID LEVEL
MOISTURE ADVECTION AHEAD OF AN APPROACHING UPPER LEVEL SHORTWAVE TROUGH
THIS MORNING. BELOW 600 HPA, ALL MODELS SHOW THE ATMOSPHERIC PROFILE
BECOMING MIXED (PARTICULARLY BELOW 800 HPA) AND AS A RESULT IS RELATIVELY
DRY. WITH THE EXCEPTION OF THE 27.00Z GFS, ALL MODELS BASICALLY HAVE
NO QPF ACROSS SOUTHWEST KANSAS TODAY. ALSO CHECKED THE ARW/NMM/HRRR
WHICH PAINT AN ALMOST NEGLIGIBLE QPF SIGNAL. AS A RESULT, HAVE REDUCED
POPS TO BELOW 15 PERCENT. SOME VIRGA IS POSSIBLE THIS MORNING BUT OTHER
THAN THAT, THE FORECAST WILL REMAIN DRY FOR TODAY.
SECOND SENSIBLE WEATHER CONCERN AND RATHER THE MOST SIGNIFICANT IS WINDS.
AS THE ABOVE MENTIONED SHORTWAVE TROUGH MOVES ACROSS KANSAS, THIS FEATURE
WILL PUSH A SURFACE COLD FRONT ACROSS THE REGION THIS MORNING. IN THE
WAKE OF THE FRONT, A TIGHT PRESSURE GRADIENT AND MIXING FROM ON AVERAGE
800 HPA TO THE SURFACE WILL RESULT IN MOMENTUM TRANSFER FROM THE TOP
OF THE BOUNDARY LAYER TO THE GROUND. BUFKIT SOUNDINGS SHOW ABOUT 40
KT AT THE TOP OF THE MIXING LAYER. AS WITH THE PREVIOUS DAY SHIFT, I
HAVE UTILIZED THE MIXED LAYER WIND SMART TOOL WHICH BROUGHT IT REASONABLE
WINDS SPEEDS INTO THE GRIDS. MOS/LAMP GUIDANCE ALSO SUGGESTS SIMILAR
WIND MAGNITUDE AS OUTPUTTED BY TOOL. THE ONGOING NPW LOOKS VERY REASONABLE
ALTHOUGH I DID ADJUST THE START TIME EARLIER AS THE HRRR MODEL IS SUGGESTING
NEAR CRITERIA WIND SPEEDS AT THE END OF THE MODEL RUN (EARLIER). WINDS
AROUND 29-33 KT WITH GUSTS TO 40-45 KT ARE FORECAST TODAY. WINDS WILL
DECREASE SIGNIFICANTLY TOWARDS SUNSET.
TONIGHT:
HIGH PRESSURE WILL SLIDE ACROSS KANSAS TONIGHT AND INTO TOMORROW MORNING.
FORECAST SOUNDINGS SHOW RAPID DRYING IN THE MID LEVELS AFTER 00Z. WITH
CLEARING SKIES AND RELATIVELY LIGHT WINDS, AM EXPECTING COOL OVERNIGHT
LOWS WITH TEENS TO LOW 20S DEG F ACROSS MUCH OF THE REGION. SUBSIDENCE
AND HIGH PRESSURE IN THE WAKE OF THE DEPARTING TROUGH WILL KEEP POPS
AT ZERO BY 06Z TONIGHT.
SATURDAY/SATURDAY NIGHT:
EXTREMELY QUIET WEATHER IS EXPECTED AS NORTHWESTERLY FLOW ALOFT PREVAILS
ACROSS THE SUNFLOWER STATE THROUGH THE BEGINNING OF THE WEEKEND. MUCH
WEAKER WESTERLY TO NORTHWESTERLY WINDS AROUND 10 TO 15 KT ARE EXPECTED
SATURDAY. TEMPERATURES WILL BE FAIRLY SEASONABLE TO SLIGHT ABOVE
WITH MID TO UPPER 40S DEG F EXPECTED. SKIES SHOULD BE FAIRLY
CLEAR. LOWS INTO SUNDAY MORNING ARE EXPECTED TO BE NEAR NORMAL...LOW
20S DEG F. -SUGDEN
DAYS 3-7...
A PROGRESSIVE, ZONAL SYNOPTIC SCALE PATTERN IS EXPECTED TO PREVAIL THROUGH
THE MEDIUM RANGE YIELDING WEAK COLD FRONT PASSAGES AND AN OVERALL CONTINUED
ABOVE-AVERAGE TEMPERATURE FORECAST.
A LEE TROUGH WILL DEVELOP SUNDAY AS AN UPPER LEVEL TROUGH BEGINS TO
ENTER THE PACIFIC NORTHWEST REGION. REMNANT, COOL POLAR AIRMASS OVER
THE CENTRAL CONUS WILL LOSE ITS GRIP WITH INCREASING LOW LEVEL THICKNESSES
AND SUBSEQUENT WARMER TEMPERATURES OVER THE WESTERN PLAINS. HIGHS SUNDAY
SHOULD WARM WELL INTO THE 50S AND HAVE INCREASED THE FORECAST HIGHS
ABOUT 2 TO 3 DEGREES ON AVERAGE ACROSS THE DDC FORECAST AREA.
MONDAY CERTAINLY LOOKS TO BE A WARM DAY WITH THE LEE TROUGH OVER EASTERN
COLORADO AND ADJACENT WESTERN KANSAS DOWN TO ABOUT 1002-1004MB. DEPENDING
ON THE DEGREE OF BOUNDARY LAYER MIXING, A VERY WARM DAY COULD RESULT...ESPECIALLY
ACROSS THE SOUTHWESTERN COUNTIES (HIGHER ELEVATION RESULTING IN BETTER
POTENTIAL FOR DEEPER MIXING). THE ALLBLEND GUIDANCE GIVES HIGHS OF 59-60F
FOR MUCH OF THE FORECAST AREA BUT SOME MID 60S CANNOT BE RULED OUT IN
THIS VERY WARM PATTERN AHEAD OF A LOW AMPLITUDE ZONAL SHORTWAVE TROUGH.
THIS AFOREMENTIONED TROUGH WILL MOVE FAST ACROSS THE CENTRAL PLAINS
MONDAY NIGHT AND TUESDAY SHOULD BE A BIT COOLER...YET STILL QUITE A
BIT ABOVE THE CLIMATOLOGICAL AVERAGE OF LOWER-MID 40S FOR SOUTHWEST
KANSAS TO END THE MONTH OF JANUARY. AFTER THAT...THERE IS SOME UNCERTAINTY
IN HOW THE PATTERN WILL EVOLVE. THE GFS SHOWS AMPLIFICATION TAKING PLACE
QUICKLY OVER THE WESTERN CONUS WITH A RIDGE AXIS OVER THE WEST COAST
AND SUBSEQUENT TROUGH OVER THE CENTRAL CONUS. THIS IS A COOLER PATTERN,
HOWEVER THE NEW ECMWF MODEL SHOWS A MUCH WARMER SCENARIO FOR MID-WEEK
WITH A MUCH LOWER AMPLITUDE RIDGE-TROUGH SETUP OVER THE WESTERN AND
CENTRAL CONUS. THE ECMWF MODEL DOES INDEED AMPLIFY THE SYNOPTIC SCALE
PATTERN RATHER SUBSTANTIALLY BY THURSDAY, RESULTING IN A MEAN TROUGH/LOWER
HEIGHTS OVER THE CENTRAL CONUS...SO THE ABOVE/MUCH ABOVE TEMPERATURES
WE WILL BE SEEING SUNDAY THROUGH WEDNESDAY MAY END BY THURSDAY- FRIDAY
OF NEXT WEEK (FEB 2-3) DEPENDING ON HOW THE AMPLIFICATION OF THE LARGE
SCALE PATTERN EVOLVES OVER THE CONUS. -UMSCHEID
&&
.AVIATION...
FOR THE 06Z TAF ISSUANCE...SOUTH TO SOUTHEAST WINDS AT 8 TO 15 KNOTS
WILL PERSIST AT THE TAF SITES THROUGH ABOUT 10Z. THE WINDS COULD OCCASIONALLY
BE GUSTY TO 20 KNOTS AS WELL. AFTER 10Z THE WINDS WILL DIMINISH AND
SWITCH TO THE SOUTHWEST AS A LOW PRESSURE TROUGH MOVES INTO THE AREA
FROM EASTERN COLORADO. A STRONG COLD FRONT WILL PUSH THROUGH WESTERN
KANSAS BETWEEN 12Z AND 14Z. WINDS BEHIND THE FRONT WILL INCREASE FROM
THE NORTH AT 25 TO 35 KNOTS AND CONTINUE INTO THE EARLY AFTERNOON HOURS
BEFORE DIMINISHING SOMEWHAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 18 49 21 / 10 0 0 0
GCK 45 18 47 20 / 10 0 0 0
EHA 45 19 49 23 / 10 0 0 0
LBL 46 18 49 21 / 10 0 0 0
HYS 47 18 47 20 / 10 0 0 0
P28 53 20 49 23 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 8 AM CST /7 AM MST/ THIS MORNING TO 6 PM CST
/5 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>066-074>081-
084>090.
&&
$$
FN36/25/25
AREA FORECAST DISCUSSION
NWS GRAY ME
139 AM EST FRI JAN 27 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST PROMPTING A COASTAL LOW
TO DEEPEN ALONG THE NEW ENGLAND COAST THIS AFTERNOON. THE LOW
WILL EXIT INTO THE CANADIAN MARITIMES TONIGHT. ANOTHER LOW
WILL TRACK THROUGH SOUTHERN CANADA ON SATURDAY NIGHT WITH A WEAK
COLD FRONT CROSSING NORTHERN NEW ENGLAND. ANOTHER FRONT WILL CROSS
NEW ENGLAND SUNDAY NIGHT WITH COLDER TEMPERATURES BEHIND IT. A
WARM FRONT WILL LIFT NORTHWARD INTO NORTHERN NEW ENGLAND TUESDAY
NIGHT AND LOW PRESSURE WILL TRACK ALONG THE WARM FRONT ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
00Z SOUNDING AT GYX REMAINS VERY DRY IN THE LOWER LEVELS. THIS
COOL/DRY AIR IS ENTRENCHED MORE THAN EVEN THE COLDEST GFS SCENARIO
HAS TO OFFER. THIS HAS KEPT PCPN IN THE FORM OF SNOW FOR A LONGER
PERIOD ACROSS SOUTHERN MAINE AND NEW HAMPSHIRE.
LATEST HRRR RUN PUSHES THE PCPN TO QUICKLY AND AGRESSIVELY INTO
THIS DRY AIR. HOWEVER...ATMOSPHERE WILL SATURDAY OVER THE NEXT
HOUR OR TWO OVER NORTHERN PORTIONS OF THE FORECAST AREA.
MAIN BAND OF STEADY PCPN WILL CONTINUE TO MOVE NORTHWARD OUT OF
SOUTHERN NEW HAMPSHIRE OVER THE NEXT FEW HOURS. PTYPE WILL
TRANSITION FROM ALL SNOW TO SLEET AND FREEZING RAIN OVER
SOUTHERNMOST NH AND FAR SOUTHWEST MAINE OVER THE NEXT HOUR OR TWO
AS WARM AIR ARRIVES BOTH IN THE BOUNDRY LAYER AND ALOFT. PTYPE
WILL SWITCH TO RAIN RIGHT ALONG THE COAST AFTER A QUICK INCH OR
TWO HAS FALLEN.
MADE SOME MINOR ADJUSTMENTS TO THE SNOWFALL MAP FOR THE WEB TO
SMOOTH AND MODIFY SOME OF THE DATA. ALL WARNINGS AND ADVISORIES
WILL REMAIN IN PLACE THROUGH 21Z.
TIMING OF CHANGEOVER AND STEADY PCPN APPEARS TO BE ON TRACK. MADE
ONLY MINOR ADJUSTMENTS TO THE GRIDS. MAY NEED TO ADDRESS THE
MARINE FCST WITH GALES SHORTLY.
FAVORED COOLER MAV TEMPS FOR TODAYS MAXES.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
AFTER SOME PCPN OVER EASTERN AREAS EARLY...CLEARING IS EXPECTED
THIS EVENING AS THE SURFACE LOW PROGRESSES INTO THE CANADIAN
MARITIMES. THIS WILL BE FOLLOWED BY A WEAK RIDGE OF HIGH PRESSURE
LATE TONIGHT. HOWEVER...SOME HIGH...THIN CLOUDINESS WILL ALREADY
BE INVADING THE SKY BY MIDDAY SATURDAY AS A WEAK TROUGH OF LOW
PRESSURE QUICKLY APPROACHES NORTHERN NEW ENGLAND. WITH DRY
ATMOSPHERE IN PLACE IN THE LOWER LEVELS...WE EXPECT ANY PCPN TO
HOLD OFF UNTIL AFTER DARK.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
OVER THE OUTLOOK PERIOD FAST MOVING CLIPPERS WITH VERY LIMITED
MOISTURE WILL BE MOVING THROUGH A RATHER ZONAL WESTERLY FLOW ALLOWING
EXCHANGES IN AIR MASSES ABOUT EVERY 48 HRS. TEMPS WILL GENERALLY
BE AVERAGING ABOVE NORMAL THROUGH MOST OF THE PERIOD.
WITH THAT GENERAL OUTLLOK IN MIND..MORE SPECIFICALLY...A RIDGE OF
HIGH PRESSURE CROSSES THE AREA ON SATURDAY WITH WARMER
TEMPERATURES AND DRY CONDITIONS.
A FAST MOVING CLIPPER MOVES EAST THROUGH ONTARIO AND INTO QUEBEC
LATE SATURDAY INTO SATURDAY NIGHT... SPREADING SCATTERED SNOW
SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND WESTERN MAINE.
A COLD FRONT WILL PUSH THROUGH AS WELL WITH COLDER TEMPERATURES
AND GUSTY WEST WINDS BEHIND IT.
A WEAK RIDGE OF PRES SETTLES OVER THE AREA SUNDAY BUT QUICKLY
FOLLOWED BY ANOTHER FAST MOVING CLIPPER THAT WILL MOVE ACROSS NEW
ENGLAND SUNDAY NIGHT WITH A WEAK SURFACE LOW TRACKING THROUGH
SOUTHERN QUEBEC. A FEW MORE LIGHT SNOW SHOWERS WILL BE POSSIBLE
MAINLY IN THE MOUNTAINS. SEASONABLY COLD AIR WILL MOVE IN FOR
MONDAY.
THE FAST FLOW ALOFT CONTINUES THROUGH THE WEEK WITH WAVE AFTER
WAVE CROSSING THROUGH THE FLOW. ANOTHER WAVE APPROACHES ON TUESDAY
WITH A WARM FRONT LIFTING NORTHWARD INTO CENTRAL PARTS OF NEW
HAMPSHIRE AND MAINE BY TUESDAY NIGHT INTO WEDNESDAY. THIS MAY LEAD
TO SOME LIGHT SNOW BUT OVERALL FORCING LOOKS WEAK UNTIL WEDNESDAY
WHEN SURFACE LOW PRESSURE TRACKS EASTWARD ALONG THE WARM FRONT.
BEST PRECIPITATION CHANCES WILL BE FURTHER TO THE NORTH. WARM AIR
IN PLACE SOUTH OF THE WARM FRONT WILL YIELD MOSTLY RAIN AS
PRECIPITATION TYPE... WHILE NORTH OF THE FRONT SNOW IS MORE
LIKELY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
MAINLY LIFR CONDITIONS...IMPROVING TO VFR THIS EVENING WITH THE
PASSAGE OF THE SURFACE LOW AND A WIND SWITCH TO THE WEST.
LONG TERM...
MOSTLY VFR CONDITIONS EXPECTED. MOST LIKELY TIMES FOR
FLIGHT RESTRICTIONS WILL BE SUNDAY NIGHT AND AGAIN TUESDAY THROUGH
WEDNESDAY.
&&
.MARINE...
SHORT TERM...
WILL LIKELY REQUIRE A GALE WARNING FOR THE OUTER WATERS TONIGHT AS
SURFACE LOW INTENSIFIES...PULLS TO OUR EAST...AND INCREASES THE
GRADIENT AS WELL AS THE COLD AIR ADVECTION.
LONG TERM...
MAY SEE WINDS REACH 30 OR 35 KT BEHIND A COLD FRONT ON
SATURDAY NIGHT. ANOTHER FAST MOVING FRONT WILL CROSS THE WATERS
SUNDAY NIGHT WITH GUSTY WINDS BEHIND IT AS WELL.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ012>014-018>022-026>028.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ005>010-013.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NWS MARQUETTE MI
1107 PM EST THU JAN 26 2012
.SHORT TERM...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A SHOTRWAVE OVER THE NRN
PLAINS POISED TO MOVE ACROSS THE AREA TONIGHT. RADAR RETURNS SHOW A
NARROW BAND OF PCPN IN FORM OF LIGHT SNOW ASSOC WITH THIS FEATURE
OVER WRN LAKE SUPERIOR AND NW WI. ANOTHER SHORTWAVE NOW OVER THE NRN
ROCKIES IS PROGGED TO MOVE INTO THE UPR MS VALLEY AND WRN GREAT
LAKES LATE FRIDAY BRINGING ANOTHER CHC FOR LIGHT SNOW FRI AFTERNOON
AND FRI NIGHT.
800-700 MB FGEN AND MODERATE MID-LVL Q-VECT CONV ALONG FRONTAL
BOUNDARY HAS RESULTED IN BAND OF LIGHT SNOW OVER WRN LAKE SUPERIOR
AND NW WI. MODELS INDICATE FGEN FORCING AND Q-VECT CONV WILL WEAKEN
SOME ALONG THE FRONTAL PASSAGE BUT THEN STRENGTH A BIT OVER THE ERN
FCST LATER THIS EVENING AND OVERNIGHT. THUS...KEPT ONLY SLIGHT CHC
POPS FOR SNOW OVER THE WRN HALF OF THE FCST AREA THIS EVENING AND
KEPT IN 30 PCT POPS OVER THE ERN COUNTIES. CLEARING LATER THIS
EVENING AND OVERNIGHT WILL ALLOW TEMPS TO FALL INTO THE TEENS OVER
THE WRN INTERIOR WHERE TEMPS ELSEWHERE SHOULD BE MAINLY IN THE LOWER
TO MID 20S. 850 MB TEMPS BEHIND THE FRONT ARE ONLY EXPECTED TO DROP
TO -8 TO -9C WHICH SHOULD NOT BE COLD ENOUGH FOR ANY LES IN WNW FLOW
BEHIND FRONT.
RDGG MOVING OVER THE AREA WILL KEEP MUCH OF THE CWA DRY ON FRIDAY.
THE ONLY EXCEPTION WILL BE FAR WRN COUNTIES FRI AFTERNOON WHERE
SHORTWAVE APPROACHING FM THE NRN ROCKIES WILL BRING ANOTHER CHC OF
SNOW LATE IN THE DAY.
.LONG TERM DISCUSSION /FRIDAY NIGHT THROUGH THURSDAY/...
FRIDAY NIGHT THROUGH SUNDAY...
LARGE SHORTWAVE OVER JAMES BAY WILL KEEP TROUGH ACROSS THE UPPER
GREAT LAKES THROUGH SUNDAY...WITH SEVERAL WEAK AND FAST MOVING
SHORTWAVES DEVELOPING ALONG THE DESCENDING BRANCH OF THE TROUGH OVER
THE FORECAST PERIOD. THE FIRST OF THESE SHORTWAVES WILL REACH THE
CWA SATURDAY MORNING...MERGING WITH A SECONDARY SHORTWAVE TO OUR
SOUTH...WITH THE ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND PRECIP
IMPACTING THE AREA BEGINNING FRIDAY NIGHT CONTINUING DURING THE DAY
ON SATURDAY. ALL MODELS ARE PERSISTENT ON THIS IDEA...HOWEVER THERE
SEEMS TO BE SOME DISAGREEMENT BETWEEN THE NAM AND OTHER MODELS AS
FAR AS THE PLACEMENT OF THE SURFACE LOW...AND RESULTING PRECIP.
BASED ON SREF DATA ALSO TRENDING AWAY FROM GENERAL NAM
SOLUTION...HAVE DECIDED TO GO WITH CONSENSUS OF OTHER MODELS WHICH
WILL KEEP SURFACE LOW AND MAIN QVECTOR CONV TO THE SOUTH...KEEPING
MAIN PRECIP ALONG THE SOUTHERN HALF OF THE CWA...WITH SOME CHANCES
POSSIBLE ACROSS THE REMAINING CWA.
AS SYSTEM PULLS OUT SATURDAY AFTERNOON...WINDS WILL TRANSITION TO A
WNW DIRECTION AND THEN EVENTUALLY TO A MORE W DIRECTION BY SATURDAY
NIGHT...BEFORE FINALLY VEERING BACK TO THE NW BY SUNDAY MORNING
AHEAD OF NEXT APPROACHING SHORTWAVE. FALLING H850 TEMPS TO AROUND
-14C BEHIND THE ASSOCIATED COLD FRONT AND AHEAD OF A DESCENDING
POLAR JET WILL INDUCE LAKE EFFECT SNOW IN WNW FAVORED REGIONS DURING
THE DAY SATURDAY...AND THEN INTENSIFY IN AREAS FAVORED BY A NW WIND
DIRECTION DURING THE DAY SUNDAY AS H850 TEMPS BOTTOM OUT TO AROUND
-18C. POTENTIAL FOR HEAVY ACCUMULATIONS IN AFFECTED AREAS IS
POSSIBLE THROUGH THIS PERIOD/SATURDAY AFTERNOON THROUGH SUNDAY
EVENING...AS INVERSION HEIGHTS RANGE BETWEEN 5K-10K FT WITH DEEP
MOISTURE AVAILABLE AT TIMES IN THE SNOW GROWTH ZONE.
SUNDAY NIGHT THROUGH THURSDAY...
STRONG RIDGE AMPLIFICATION OVER THE WESTERN U.S. WILL ALLOW LARGE
SHORTWAVE TO REMAIN STATIONARY ACROSS HUDSON BAY...WITH A RESULTING
TROUGHING PATTERN ACROSS THE GREAT LAKES REGION. THIS SHARP TROUGH
WILL ALLOW THE POLAR JET TO DIP DOWN AS FAR SOUTH AS KENTUCKY SUNDAY
NIGHT...WHICH WILL TRANSLATE TO THE RETURN OF MUCH COLDER
TEMPERATURES TO THE REGION. H850 TEMPS OF -18C OVER THE LAKE WILL
KEEP SOME LINGERING CHANCES OF LES IN AREAS FAVORED BY NW
WINDS...QUICKLY DIMINISHING AS WAA ADVECTION COMES IN TO PLAY AND
WINDS BACK TO A MORE SW DIRECTION. AT THIS POINT/SUNDAY NIGHT/ THE
POLAR JET WILL MERGE WITH THE SUBTROPICAL JET AND MOVE
EASTWARD...WHICH WILL SLOWLY LIFT THE STATIONARY TROUGH TO THE
NORTHEAST AND RETURN MUCH OF THE US TO A MORE ZONAL FLOW BY MONDAY
NIGHT. WEAK SURFACE DISTURBANCE WILL FORM ALONG THE DESCENDING
BRANCH OF THIS SHORTWAVE...BRINGING A CHANCE FOR SYNOPTIC SNOWFALL
MONDAY...BEFORE QUICKLY MOVING OFF TO THE EAST FOLLOWING THE GENERAL
UPR LEVEL FLOW. SOME MODEL DISAGREEMENTS ON TIMING AND STRENGTH OF
THIS SHORTWAVE...WITH GFS BEING MORE PROGRESSIVE AND ECMWF BEING
SLOWER YET STRONGER...SO HAVE GONE WITH A GENERAL CONSENSUS.
THE NEXT SHORTWAVE WILL TRACK ACROSS THE AREA SOMETIME
TUESDAY/TUESDAY NIGHT NIGHT...WITH SAME DISAGREEMENT AND LOW
CONFIDENCE BETWEEN THE MODELS ON THE EXACT LOCATION AND STRENGTH.
ECMWF AND GEM ARE MORE PROGRESSIVE WITH THE ARRIVAL OF THE
SHORTWAVE...HAVING IT AMPLIFYING IT OVER THE GREAT LAKES REGION BY
TUESDAY MORNING...GFS ON THE OTHER HAND KEEPS THE LOW FARTHER TO OUR
SOUTH...PASSING ACROSS LAKE MI BY LATE TUESDAY NIGHT. DESPITE
DISAGREEMENTS ON PLACEMENT...STRONG MOISTURE AVAILABILITY/PWAT
VALUES 200 PCT ABOVE NORMAL/ AND WAA WILL BE ENOUGH TO KEEP CHANCES
OF PRECIP IN BOTH TUESDAY AND WEDNESDAY...ESPECIALLY EAST HALF OF
THE CWA. THIS AMPLIFIED TROUGH WILL ONCE AGAIN BRING SOME COLDER
TEMPERATURES IN DURING THE OVERNIGHT HOURS TUESDAY NIGHT. UPPER
GREAT LAKES SHOULD THEN TRANSITION TO A RIDGING PATTERN WITH
RELATIVELY QUIET WEATHER THROUGH THE REMAINDER OF THE FORECAST
PERIOD.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT MVFR CIGS TO CLEAR OVERNIGHT AT KIWD AND KCMX WITH SOME IFR
CIGS BRIEFLY AT KSAW. A COLD FRONT WILL CONTINUE MOVING THROUGH
OVERNIGHT AND ASSOCIATED MIXING AND DRIER AIR SHOULD ALLOW MVFR CIGS
TO LIFT AND VFR CONDITIONS TO PREVAIL OVERNIGHT THROUGH FRI
AFTERNOON AT ALL SITES. ANOTHER COLD FRONT MOVES THROUGH FRI EVENING
WITH COLDER AIR COMING IN AND CAUSING MVFR CIGS AND VIS AT ALL SITES
WITH SOME LIGHT SNOW.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT GUSTY SW WINDS TO 25 KTS INTO EARLY THIS EVENING AHEAD OF
APPROACHING TROUGH. AFTER THE TROUGH PASSES...W/WNW WINDS WILL
INCREASE TO 30 KTS...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR
THIS EVENING INTO FRI MORNING. THERE COULD BE A FEW GALE FORCE GUSTS
TO 35 KTS BUT PREVAILING WIND SPD SHOULD STAY BLO GALES. A SERIES OF
TROUGHS WILL THEN PASS THROUGH FRIDAY NIGHT THROUGH SUNDAY BEFORE
HIGH PRESSURE MOVES OVERHEAD SUN NIGHT AND MONDAY. EACH OF THESE
TROUGHS WILL BRING INCREASED WINDS...WITH A POSSIBLE PERIOD OF GALES
SAT AFTERNOON INTO SAT EVENING...MAINLY OVER THE ERN HALF OF THE
LAKE WHERE A GALE WATCH HAS BEEN ISSUED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR
LSZ265>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JMW
AVIATION...07
MARINE...VOSS
FORECAST. PREVIOUS FORECAST DISCUSSION FOLLOWS:
LIGHT NORTHWEST FLOW SUN WILL INCREASE TO 15 TO 20 KT SUN NIGHT
WITH ARRIVAL OF COLD SURGE. PERIOD OF INCREASED WINDS IS BRIEF AND
DOES NOT LOOK LIKE HEADLINES WILL BE WARRANTED. SURFACE HIGH
BUILDS INTO FROM THE WEST MON WITH LIGHT NORTHERLY FLOW BECOMING
NORTHEAST DURING THE AFTERNOON. CENTER OF HIGH SHIFTS OFFSHORE
EARLY TUE WITH LIGHT RETURN FLOW DEVELOPING. OTHER THAN WITH THE
COLD SURGE SUN NIGHT WINDS WILL BE 10 KT OR LESS THROUGH THE
PERIOD. SEAS WILL RUN 2 TO 3 FT WITH THE EXCEPTION OF SUN NIGHT
WHEN SEAS NEAR 20 NM MAY APPROACH 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
AMZ254- 256.
SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...III
AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1245 AM EST FRI JAN 27 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWEEP ACROSS THE REGION THIS MORNING. THE
ACCOMPANYING COLD FRONT WILL BE ACCOMPANIED BY A BAND OF SHOWERS AND
ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL FOLLOW THIS AFTERNOON
INTO THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH FRIDAY/...
AS OF 1030 PM THURSDAY...
TONIGHT: A HIGH SHEAR AND LOW -- BUT HIGHER THAN RECENT NON-EVENTS
CAPE -- SEVERE WEATHER THREAT REMAINS FOR LATE TONIGHT INTO EARLY
FRIDAY.
AT 10 PM...A DEEPENING...SUB-1000 MB SURFACE CYCLONE WAS LOCATED
OVER CENTRAL KY...WITH A TRAILING COLD FRONT THAT STRETCHED SOUTH
SOUTHWESTWARD THROUGH CENTRAL AL. A SEPARATE FRONTAL ZONE STRETCHED
ALONG THE IMMEDIATE LEE OF THE APPALACHIANS FROM GA TO VA...WHICH IS
BEING ENHANCED BY A LONG-LIVED AND NOW SUB-SEVERE PRE-FRONTAL SQUALL
LINE THAT STRETCHED FROM THE WESTERN CAROLINAS...TO EAST-CENTRAL
GA...TO THE EASTERN GOM...WELL AHEAD OF THE PRIMARY SURFACE COLD.
MEANWHILE ALOFT...WV IMAGERY AND RAOB DATA INDICATE THE FORMER
CLOSED MID-UPPER LOW HAS OPENED OVER THE WESTERN TN VALLEY AND
BECOME EMBEDDED IN A PHASED FULL-LATITUDE UPPER TROUGH THAT SPANNED
THE LOWER 48 FROM ONTARIO TO MEXICO. THIS WAVE WILL ACCELERATE WEST
OF THE APPALACHIANS WITHIN AN OBSERVED 130 KT SOUTHWESTERLY UPPER
JET TONIGHT...WHILE A NORTHERN STREAM WAVE AND ASSOCIATED MID LEVEL
COLD POOL/CAA WILL CONTINUE TO AMPLIFY SHARPLY INTO CENTRAL MS/AL
BEFORE IT TOO ACCELERATES NORTHEASTWARD...ACROSS THE CAROLINAS EARLY
FRI. LARGE SCALE FORCING FOR ASCENT...CHARACTERIZED BY 00Z OBSERVED
MID-UPPER HEIGHT FALLS AROUND 150 METERS FROM KBNA TO KJAN...WILL
ACCORDINGLY STEADILY INCREASE EAST OF THE APPALACHIANS THROUGH THE
LATE-MORNING HOURS ON FRI. A SIGNIFICANT LOW LEVEL ACCELERATION WILL
ACCOMPANY THE STRONG MID-UPPER FORCING...AND RESULT IN THE FORECAST
DEVELOPMENT OF A 50-60 KT 925 MB JET THROUGH THE CENTRAL AND EASTERN
CAROLINAS AFTER 06Z...WHICH WILL FURTHER ENHANCE ALREADY ADEQUATE
LOW LEVEL SHEAR AND PROMOTE INCREASINGLY BREEZY CONDITIONS OVER THE
CAROLINAS. INDEED...UPSTREAM VWP DATA FROM KCAE AND KGSP INDICATE A
100 PERCENT INCREASE IN THIS LLJ...FROM 20 KTS JUST A FEW HOURS AGO
TO 40-50 KTS AT 10 PM.
SINCE LARGE-SCALE FORCING AND LOW-DEEP SHEAR WILL BE PLENTIFUL...THE
TWO WILDCARDS ARE 1) HOW THE PRE-FRONTAL SQUALL LINE MAY ALTER
VERTICAL MOTION ON THE MESOSCALE OVER OUR REGION...AND 2) HOW MUCH
(BOUNDARY LAYER-BASED) INSTABILITY MATERIALIZES - THE LATTER OF
WHICH SEEMS MORE STRAIGHTFORWARD. NAM/WRF AND RUC SOLUTIONS INDICATE
THE DEVELOPMENT OF 300-500 J/KG AFTER 4 AM...AND THIS LOOKS
REASONABLE GIVEN CURRENT SURFACE OBSERVATIONAL DATA THAT INDICATES
TEMPERATURES WILL HOLD STEADY OR RISE SLIGHTLY THROUGH THE LOWER TO
MIDDLE 60S...WITH DEWPOINTS FOLLOWING A SIMILAR TENDENCY AND ABOUT
2-4 DEGREES LOWER. THE GFS ON THE OTHER HAND IS TOO COOL AND DRY IN
THE BOUNDARY LAYER AND ACCORDINGLY DEPICTS LITTLE TO NO CAPE. HOW
THE SQUALL LINE AFFECTS THE DOWNSTREAM ENVIRONMENT REMAINS MORE
PROBLEMATIC AND MAY NOT BECOME FULLY EVIDENT UNTIL A POSSIBLE SEVERE
WEATHER EVENT IS UPON US...BUT THE MAGNITUDE OF APPROACHING
LARGER-SCALE FORCING MAY RENDER ANY PRECEDING MESOSCALE EFFECTS
MOOT.
WE ACCORDINGLY EXPECT AN UPSWING IN CONVECTIVE INTENSITY LATE
TONIGHT...PERHAPS IN TWO ROUNDS WITH FIRST THE PRE-FRONTAL SQUALL
LINE...FOLLOWED BY PROBABLY STRONGER DEVELOPMENT UPSTREAM OVER AL/GA
THAT IS FOCUSED BENEATH THE MORE CONCENTRATED FORCING AND CAA ALOFT.
THE COMBINATION OF SHEAR (AND SOUTHWESTERLY DEEP SHEAR VECTORS) AND
ALBEIT WEAK INSTABILITY WILL SUPPORT A CONDITIONAL PROBABILITY OF A
FEW LOW-TOPPED SUPERCELLS AND BOWS WITH AN ATTENDING THREAT OF
DAMAGING WINDS AND ISOLATED TORNADOES...MAINLY BETWEEN 4 AND 10 AM.
WHILE THIS THREAT WILL EXIST ACROSS ALL OF CENTRAL NC...THERE MAY BE
A RELATIVE MAXIMUM TORNADIC THREAT OVER THE FOOTHILLS AND WESTERN
PIEDMONT...INVOF THE AFOREMENTIONED LEE OF THE APPALACHIANS FRONTAL
ZONE. INTERESTINGLY...RECENT HRRR RUNS INDICATE VERY LITTLE UPSTREAM
DEVELOPMENT...AND INSTEAD A RE-INVIGORATION OF THE PRE-FRONTAL
CONVECTION OVER THE EASTERN TWO THIRDS OF THE CWFA. -MWS
FRI AFTERNOON AND EVENING: THE 12Z RUN ALSO SHOWS SOME POTENTIAL FOR
A LINE OF SHORT-LIVED LIGHT SHOWERS TO DEVELOP IN THE EARLY EVENING
HOURS. WINDS ARE EXPECTED TO BE SUSTAINED AT 15-20 KTS...GUSTING TO
BETWEEN 25 AND 30 KTS. HIGHS TOMORROW ARE EXPECTED TO BE IN THE LOW
60S ACROSS THE NORTHWEST TO NEAR 70 IN THE SOUTHEAST. -KMC
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM THURSDAY...
MODIFIED SOUTHERN STREAM SFC HIGH OVER THE GULF COAST STATES WILL
BRIEFLY BUILD INTO THE AREA FRIDAY NIGHT THROUGH EARLY SATURDAY.
A PAIR OF MOISTURE-DEPRIVED CLIPPER LIKE DISTURBANCES WILL THEN
DRIVE A SERIES OF DRY COLD FRONTAL PASSAGES SOUTHEASTWARD THROUGH
THE AREA LATE SATURDAY AFTERNOON AND THEN AGAIN SUNDAY
AFTERNOON/EVENING. EACH PASSING FRONT WILL BRING MARGINALLY COOLER
AIR INTO THE REGION.
THUS..EXPECT ANOTHER MILD DAY ON SATURDAY FEATURING HIGHS IN THE
UPPER 50S TO LOWER 60S...WITH HIGHS TEMPERATURES BRIEFLY FALLING
BACK TO MORE SEASONABLE READINGS OF UPPER 40S TO LOWER 50S SUNDAY
AND MONDAY. LOWS FRIDAY NIGHT IN THE MID TO UPPER 30S...WITH NEAR
FREEZING MINS SATURDAY NIGHT AND NEAR 30 READINGS SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM WEDNESDAY...
UNSEASONABLY MILD TEMPERATURES TO CONTINUE NEXT WEEK.
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT THAT THE LARGE SCALE FLOW
OVER THE CONUS WILL QUICKLY FLATTEN/ZONAL OUT TO START THE WORK WEEK
WITH TEMPERATURES MODERATING AS SURFACE HIGH SHIFTS OFF THE
SOUTHEAST COAST. THE RESULTANT SOUTHERLY RETURN FLOW WILL MAKE 60
DEGREE READINGS PAR FOR THE COURSE BY WEDNESDAY WITH MIN
TEMPERATURES ONLY GETTING DOWN INTO THE 40S.
THERE REMAINS LITTLE RUN-TO-RUN CONSISTENCY WRT TO THE
DEVELOPMENT/AMPLITUDE OF A LOW AMPLITUDE SHORTWAVE TROUGH BY THE MID
TO LATE WEEK TIME FRAME. GIVEN THE ZONAL FLOW ALOFT THERE REMAINS
QUESTIONS IF THERE WILL BE ENOUGH MOISTURE TRANSPORT...AND THUS WILL
CARRY ONLY A SLIGHT CHANCE POP FOR NOW.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 1245 AM FRIDAY...
24-HR TAF PERIOD:
A COLD FRONT WILL MOVE THROUGH THE REGION BETWEEN 500 AM AND 900 AM
IN THE WEST... AND 700 AM AND 1000 AM IN THE EAST. GUSTY SSW WINDS
TO 30KT WILL OCCUR OUT AHEAD OF THE FRONT. A BAND OF SHOWERS AND
POTENTIALLY ISOLATED THUNDERSTORMS IS EXPECTED TO AFFECT THE REGION
WITH THE FRONTAL PASSAGE. IFR CIGS CAN GENERALLY BE EXPECTED... WITH
VFR VSBYS EXCEPT DROPPING TO IFR VSBYS WITH THE SHOWERS.
EXPECT THE FRONT AND ANY LINGERING SHOWERS AND ASSOCIATED LOWER
CIGS/VSBYS TO BECOME VFR CIGS/VSBYS BY LATE MORNING OR EARLY
AFTERNOON. WINDS WILL SHIFT TO THE WEST AT 15-25KT BEHIND THE
FRONT... AND CONTINUE THROUGH THE DAY.
LOOKING AHEAD:
WINDS WILL QUICKLY WEAKEN AND BECOME LIGHT/VARIABLE BY OR SHORTLY
AFTER SUNSET FRIDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM
THE WEST. THERE IS RELATIVELY HIGH CONFIDENCE THAT DRY/VFR
CONDITIONS WILL RULE FRIDAY NIGHT THROUGH EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/KC
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...BADGETT/BSD
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
135 AM EST FRI JAN 27 2012
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION THIS MORNING. ANOTHER
LOW PRESSURE SYSTEM COMING OUT OF THE NORTHERN PLAINS AND INTO THE
GREAT LAKES WILL BRING A SECOND COLD FRONT THROUGH THE AREA ON
SATURDAY. HIGH PRESSURE WILL BE OVER THE EASTERN UNITED STATES
SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 116 AM EST FRIDAY...
HAVE TWO MAIN AREAS OF CONCERN. SHOWERS MOVING ALONG THE BLUE
RIDGE ARE BRINGING THE STRONG 8H WINDS DOWN WITH GUSTS OVER 45 MPH
BEING REPORTED WITH SOME OF THE SHOWERS. CONTEMPLATED A WIND
ADVISORY BUT THE TIMING OF THE WINDS WILL BE MAINLY LESS THAN AN
HOUR OR TWO WITH SHOWERS...SO OPTED TO GO WITH SPECIAL WX
STATEMENTS TO COVER THE STRONGER GUSTS. ONE THING OF NOTE IS THE
DEEP CONVECTION IN THE NE GULF OF MEXICO WHICH IS ROBBING THE
MOISTURE INFLOW INTO OUR AREA...WHICH WILL CUT DOWN ON QPF SOME.
WITH THE COLD FRONT/SFC LOW IS ANOTHER STRONGER LINE OF CONVECTION
FORMING AND HAVE AN SPS COVERING THIS AND WILL BE MONITORED FOR
POTENTIAL WARNINGS. THE LATEST RUC SHOWS TWO SPEED MAXES AT
8H...ONE MOVING ACROSS THE BLUE RIDGE AND THE OTHER UP INTO
WV. THIS LOW LVL JET WILL BE EAST OF THE MTNS BEFORE DAWN IN
ADDITION TO THE COLD FRONT. KEPT HIGHEST POPS ALONG AND WEST OF
THE BLUE RIDGE EARLY THEN TRANSITION TO THE EAST THROUGH DAWN. DRY
SLOT ON WV LOOP WORKING INTO THE SMOKYS WILL SURGE INTO OUR MTNS
BY 12Z TODAY AND NAM/CMC SHOWING CLEARING BUT GFS HOLDING ONTO
MORE CLOUDS. LOOKING AT IR SAT...THE CLEARING LINE IS LAGGING BACK
INTO NRN MS/WRN TN.
ON FRIDAY...ONCE THE FRONT GOES THROUGH MODELS WERE SHOWING RAPID
DRYING...PARTLY DUE TO STRONG DOWNSLOPING EAST OF THE BLUE RIDGE.
HOWEVER THE SAME STRONG NORTHWEST SURFACE AND LOW LEVEL WIND WILL
HOLD CLOUDS IN THE MOUNTAINS FOR MUCH OF THE MORNING. HAVE ENDED
SHOWERS A BIT FASTER IN THE EAST AND DIMINISHED THE CHANCE OF
PRECIPITATION IN THE WEST BY THE END OF THE DAY.
MODELS WERE SHOWING +8 TO +10 MB/3HR PRESSURE RISES AND MODEST COLD
AIR ADVECTION BEHIND THE FRONT ON FRIDAY MORNING. ONCE MIXING BEGINS
EXPECT GUSTY WINDS TO CONTINUE THROUGH AT LEAST MID AFTERNOON. NO
ADVISORY PLANNED AT THIS TIME. PEAK GUSTS LOOK TO BE JUST UNDER 45
MPH.
FOR LOWS TONIGHT...SINCE THE SURFACE DEW POINTS CONTINUE TO
RISE...DO NOT EXPECT MUCH OF A FALL IN TEMPERATURES. WILL GO ABOVE
GUIDANCE FOR MINIMUM TEMPERATURE. 850 MB TEMPERATURES BEHIND THE
FRONT DROP IN THE MORNING...SO HOURLY TEMPERATURE TREND WILL
MOSTLY LIKELY BE NON DIURNAL ON FRIDAY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 300 PM EST THURSDAY...
TWO FAST MOVING CLIPPERS WILL THROW CLOUDS AND COLDER WEATHER OUR
WAY FOR SUNDAY. SOME RAIN/SNOW SHOWERS AND SPRINKLES/FLURRIES
WILL BE POSSIBLE WITH BOTH OF THESE...BUT MORE SO WITH THE SECOND
CLIPPER PASSING THROUGH SUNDAY AFTERNOON...WHICH MAY TAKE A MORE
SOUTHERLY TRACK WITH COLDER AIR IN PLACE. DECENT WIND GUSTS WITH
EVAP COOLING WILL ACCOMPANY ANY VIRGA WHICH CROSSES THE RIDGES. THE
DOWNSLOPE WARMING WILL CREATE STEEP LAPSE RATES...NEARLY DRY
ADIABATIC AND DEEP MIXING TO H7 AS SHOWN ON NAM/GFS BUFKIT PROFILES.
MOMENTUM TRANSFER AT THE TOP OF THE MIXED LAYER IS 60 KTS IN THE NEW
RIVER VALLEY NEAR 7P SUNDAY...AND THE NAM IS ACTUALLY A LITTLE BIT
WEAKER. THIS IS PROBABLY BECAUSE THE OP GFS IS THE MOST AMPLIFIED
SOLUTION. NONETHELESS...CAN`T RULE OUT ADVISORY GUSTS WITH THIS
INVERTED V PROFILE ATOP THE RIDGES OF THE WESTERN HALF OF THE CWA.
A QUICK BURST OF SNOW SHOWERS SUNDAY NIGHT COULD PUT DOWN A QUICK
COATING OF SNOW IN WESTERN GREENBRIER COUNTY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM EST THURSDAY...
WILL BE LOOKING AT A SERIES OF WEAK COLD FRONTS PASSING ACROSS OUR
AREA DURING THE EXTENDED PERIOD...BUT DO NOT EXPECT ANY HIGH WEATHER
IMPACTS TO OUR AREA THROUGH THE FIRST FEW DAYS OF FEBRUARY. HIGH
PRESSURE WILL BUILD ACROSS OUR AREA ON MONDAY IN THE WAKE OF A
DEPARTING COLD FRONT...AND WE CAN EXPECT MOSTLY CLEAR SKIES AND
LIGHT NORTHWEST WINDS. BECAUSE THE DOME OF HIGH PRESSURE BUILDING IN
IS MORE PACIFIC IN ORIGIN RATHER THAN CANADIAN...WE CAN EXPECT THE
SEASONABLE TEMPERATURES TO CONTINUE ACROSS OUR AREA...WITH OVERNIGHT
LOWS IN THE UPPER 20S TO LOW 30S...AND MONDAY AFTERNOON HIGHS
RANGING FROM THE UPPER 30S IN THE MOUNTAINS...TO THE MID TO UPPER
40S ACROSS THE PIEDMONT REGION.
HIGH PRESSURE WILL PASS EAST OF OUR AREA ON MONDAY NIGHT AND
TUESDAY...ALLOWING OUR WINDS TO BECOME SOUTHERLY AND FOR
TEMPERATURES TO ENTER A WARMING TREND. EXPECT THAT WE WILL START OUT
THE DAY WITH MOSTLY SUNNY SKIES...BUT THAT CLOUDS WILL INCREASE
DURING THE EVENING AS ANOTHER COLD FRONT APPROACHES FROM THE WEST.
SHOWER ACTIVITY WILL BEGIN TO MAKE ITS WAY INTO OUR SOUTHEAST WEST
VIRGINIA AND MOUNTAIN EMPIRE REGION COUNTIES.
THE COLD FRONT IS EXPECTED TO PUSH THROUGH OUR AREA ON WEDNESDAY
AFTERNOON. WITH LIMITED MOISTURE TO WORK WITH...THIS COLD FRONT IS
EXPECTED TO TRIGGER ONLY SPOTTY LIGHT SHOWER ACTIVITY. HIGH PRESSURE
BUILDS IN QUICKLY BEHIND THE COLD FRONT ON WEDNESDAY AFTERNOON...AND
PASSES JUST AS QUICKLY TO THE EAST OF OUR AREA BY THURSDAY MORNING.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
AS OF 1115 PM EST THURSDAY...
A COLD FRONT CONTINUES TO APPROACH THE REGION FROM EASTERN
KENTUCKY. IN ADVANCE OF IN SOUTHERLY FLOW SOUTH OF A WARM FRONT IS
INCREASING. SHOWERS ARE NUMEROUS ALONG A LINE FROM KUKF TO
KHSP...INCLUDING TAF SITES KBCB AND KROA. EXPECTING COVERAGE TO
CONTINUE TO BE GOOD IN THIS REGION HEADING INTO THE EARLY MORNING
HOURS OF FRIDAY...ALL WHILE THE PRECIPITATION MAKES PROGRESSION
EASTWARD AS WELL. THERE MAY BE AN HOUR OR TWO GAP BETWEEN THIS
PRE-FRONTAL PRECIPITATION AND LOCALLY HEAVIER PRECIPIATION THAT
ARRIVES WHEN THE FRONT MOVES THROUGH BETWEEN 10Z...5AM WEST....AND
14Z...9AM EAST. MOST AREA WILL TREND TO IFR/MVFR CIGS AND THEN
IMRPOVE BEHIND THE FRONT...ESPECIALLY IN THE EAST WHERE WINDS
WILL HAVE A STRONG DOWNSLOPE COMPONENT.
AS OF 640 PM EST THURSDAY...
CONVECTION AND MVFR CIGS HAVE BEEN SLOWER TO FILL IN THAN
PREVIOUSLY ANTICIPATED. AS SUCH...HAVE SLOWED ONSET OF PREVAILING
PRECIPITION AND LOWER CIG THRESHOLDS BY ROUGHLY TWO HOURS ACROSS
THE BOARD. OTHER ASPECTS OF EARLIER FORECAST STILL RELATIVELY ON
TRACK SAVE THE ONSET OF LLWS. THIS TOO HAS BEEN DELAYED BY AROUND
TWO HOURS AT MOST LOCATIONS.
AS OF 108 PM EST THURSDAY...
THERE WILL BE SCATTERED TO ISOLATED THUNDERSTORMS...SOME WITH
VERY GUSTY WINDS ALONG WITH THE BAND OF SHOWERS. LOW CONFIDENCE
THAT ANY INDIVIDUAL TAF SITE WILL GET A THUNDERSTORM. THE MOST
LIKELY LOCATION WOULD BE DAN SO HAVE ADDED CB CLOUD TYPE IN LATE
TONIGHT.
BOTTOM OF THE 55-65 KNOT LOW LEVEL JET JUST REACHES THE 2000 FOOT
CRITERIA FOR LLWS SO HAVE INCLUDED IN THE TAFS AHEAD OF THE FRONT
THROUGH MOST OF THE NIGHT. ONCE MIXING BEGINS IN THE MORNING
BEHIND THE FRONT GUSTS MAY REACH 30 KNOTS DUE TO STRONG PRESSURE
RISES AND MODEST COLD AIR ADVECTION.
THE STRONG NORTHWEST WINDS CLEAR OUT THE CLOUDS BEHIND THE FRONT
FRIDAY EAST OF THE BLUE RIDGE. UPSLOPE CLOUDINESS WILL LINGER IN
SE WV...WITH MVFR CIGS MUCH OF FRIDAY.
COULD SEE SOME MVFR CEILINGS ACROSS THE WV TAF SITES SATURDAY AND
SATURDAY NIGHT WITH A CLIPPER MOVING ACROSS THE REGION. OTHERWISE
SATURDAY AND SUNDAY FLIGHT CONDITIONS WILL BE VFR.
&&
.FIRE WEATHER...
WINDS WILL GUST BEHIND THE FRONT ON FRIDAY WITH GOOD DRYING EAST
OF THE BLUE RIDGE AND GUSTS UP TO 45 MPH AT HIGHER ELEVATIONS.
THERE MAY BE SOME RED FLAG CRITERIA RH AND WIND SUNDAY...HOWEVER THE
GROUND WILL PROBABLY BE STILL TOO MOIST AND FUEL STICK MOISTURES
PROBABLY WILL NOT MAKE CRITERIA. WILL MENTION IN THE FWF DISCUSSION.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...AMS/DS/WP
SHORT TERM...KM
LONG TERM...NF
AVIATION...AMS/DS/WP
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
757 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY. WIND GUSTS TO 30 KTS POSSIBLE
SATURDAY.
RATZER
//DISCUSSION...UPDATED 12Z...
THE DAYTIME PERIOD IS EXPECTED TO BE QUIET AVIATION-WISE
TODAY...BUT SOME CLOUDS PRIOR TO DAYBREAK AND SOME SNOW TONIGHT
ARE THE FORECAST CHALLENGES. THE 020-030 CIGS THIS MORNING WILL
CONTINUE TO DEPART AS A BRIEF AND WEAK HIGH PRESSURE RIDGE AND
DRIER LOW-LEVEL AIR MASS SPREAD INTO THE AREA. WINDS WILL REMAIN
NORTHWEST THIS MORNING BEFORE BACKING TO THE SOUTHWEST FROM 17Z
THROUGH 22Z. AN UPPER LEVEL DISTURBANCE WILL MOVE OVER THE AREA
TONIGHT...LEADING TO SNOWFALL BY MID-EVENING AT ALL TAF SITES. IT
IS POSSIBLE THE START TIME IS SLIGHTLY EARLIER AT EACH AIRPORT
THAN PRESENTLY FORECAST. THE FORCING AND DEEPER MOISTURE FOR SNOW
IS FAIRLY PROGRESSIVE...SO THE WINDOW FOR IFR VISIBILITY AND MVFR
CIGS IN SNOW LOOKS TO BE THREE TO FIVE HOURS. THE CIGS ARE FAVORED
TO LAST SLIGHTLY AFTER THE ACCUMULATING SNOW ENDS...AND SO MIGHT
SOME FLURRIES. TOTAL ACCUMULATION AT AREA TAF SITES IS EXPECTED TO
BE BETWEEN ONE AND TWO INCHES AT THIS TIME...WITH THE SNOW
INITIALLY BEING WET AND THEN BECOMING MORE DRY AS IT WRAPS UP. IN
ADDITION...WINDS WILL BEGIN TO VEER GRADUALLY BACK TOWARDS THE
WEST AND INCREASE IN SPEED ONCE THE SNOW BEGINS THIS EVENING...AND
THEN SHARPLY TO THE NORTHWEST AND BECOME QUITE GUSTY ONCE THE
SYSTEM COLD FRONT PASSES BETWEEN 08Z AND 11Z. SOME SHALLOW BLOWING
SNOW IS LIKELY LATE TONIGHT INTO SATURDAY MORNING. WINDS ARE
FAVORED TO GUST AS HIGH AS 30 KT ON SATURDAY BETWEEN 15Z AND 22Z.
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING. IT MAY NEED TO BE ADJUSTED AN HOUR EARLIER
DEPENDING ON TRENDS TODAY.
* MEDIUM CONFIDENCE IN WIND TRENDS...BUT HIGH CONFIDENCE IN GUSTS
TO 20 KTS LATE TONIGHT AND TO NEAR 30 KTS BY MID MORNING
SATURDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 2 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
527 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CIGS GRADUALLY MOVING OUT FROM NORTH TO SOUTH THROUGH THE EARLY
MORNING.
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY.
//DISCUSSION...UPDATED 12Z...
THE DAYTIME PERIOD IS EXPECTED TO BE QUIET AVIATION-WISE
TODAY...BUT SOME CLOUDS PRIOR TO DAYBREAK AND SOME SNOW TONIGHT
ARE THE FORECAST CHALLENGES. THE 020-030 CIGS THIS MORNING WILL
CONTINUE TO DEPART AS A BRIEF AND WEAK HIGH PRESSURE RIDGE AND
DRIER LOW-LEVEL AIR MASS SPREAD INTO THE AREA. WINDS WILL REMAIN
NORTHWEST THIS MORNING BEFORE BACKING TO THE SOUTHWEST FROM 17Z
THROUGH 22Z. AN UPPER LEVEL DISTURBANCE WILL MOVE OVER THE AREA
TONIGHT...LEADING TO SNOWFALL BY MID-EVENING AT ALL TAF SITES. IT
IS POSSIBLE THE START TIME IS SLIGHTLY EARLIER AT EACH AIRPORT
THAN PRESENTLY FORECAST. THE FORCING AND DEEPER MOISTURE FOR SNOW
IS FAIRLY PROGRESSIVE...SO THE WINDOW FOR IFR VISIBILITY AND MVFR
CIGS IN SNOW LOOKS TO BE THREE TO FIVE HOURS. THE CIGS ARE FAVORED
TO LAST SLIGHTLY AFTER THE ACCUMULATING SNOW ENDS...AND SO MIGHT
SOME FLURRIES. TOTAL ACCUMULATION AT AREA TAF SITES IS EXPECTED TO
BE BETWEEN ONE AND TWO INCHES AT THIS TIME...WITH THE SNOW
INITIALLY BEING WET AND THEN BECOMING MORE DRY AS IT WRAPS UP. IN
ADDITION...WINDS WILL BEGIN TO VEER GRADUALLY BACK TOWARDS THE
WEST AND INCREASE IN SPEED ONCE THE SNOW BEGINS THIS EVENING...AND
THEN SHARPLY TO THE NORTHWEST AND BECOME QUITE GUSTY ONCE THE
SYSTEM COLD FRONT PASSES BETWEEN 08Z AND 11Z. SOME SHALLOW BLOWING
SNOW IS LIKELY LATE TONIGHT INTO SATURDAY MORNING. WINDS ARE
FAVORED TO GUST AS HIGH AS 30 KT ON SATURDAY BETWEEN 15Z AND 22Z.
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN EXACT CLEARING TIME OF MORNING CLOUDS. HIGH
CONFIDENCE THE CLEARING IS PRIOR TO 14Z.
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING. IT MAY NEED TO BE ADJUSTED AN HOUR EARLIER
DEPENDING ON TRENDS TODAY.
* MEDIUM CONFIDENCE IN WIND TRENDS...BUT HIGH CONFIDENCE IN GUSTS
TO 20 KTS LATE TONIGHT AND TO NEAR 30 KTS BY MID MORNING
SATURDAY.
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 2 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
422 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* LOW CEILINGS GRADUALLY DEPARTING FROM NORTHWEST TO SOUTHEAST
SOON AFTER DAYBREAK.
* VISIBILITY GRADUALLY IMPROVING.
* SNOW TONIGHT...MAINLY BETWEEN 03Z AND 08Z.
//DISCUSSION...UPDATED 06Z...
A SLOW MOVING COLD FRONT IS MOVING ACROSS THE MISSISSIPPI RIVER THIS
EVENING WITH CONDITIONS QUICKLY IMPROVING TO VFR BEHIND THE FRONT.
AHEAD OF THE FRONT...WIDESPREAD IFR/LIFR CONDITIONS PERSIST MAINLY
DUE TO LOW CIGS...WITH VARIABLE VSBY. VSBY SHOULD SHOW A GRADUAL
IMPROVING TREND OVER NEXT COUPLE HOURS AS WIND SPEEDS PICK UP
AHEAD OF THE FRONT TONIGHT...BUT CIGS WILL HOLD STEADY OR MAY FALL
SOME AS WEAK PRESSURE FALLS CONTINUE TO OVERSPREAD THE AREA. SKIES
SHOULD QUICKLY CLEAR IN THE EARLY MORNING HOURS...~06Z AT RFD AND
09-10Z FOR THE CHICAGO AREA TERMINALS...AS ANTICYCLONIC FLOW
MOVES ACROSS THE REGION BEHIND THE COLD FRONT.
MOST OF FRIDAY WILL HAVE RELATIVELY QUIET WEATHER CONDITIONS WITH
WESTERLY WINDS GRADUALLY BACKING TO THE SOUTHWEST THROUGH THE DAY AS
ANOTHER CLIPPER SYSTEM PUSHES EAST ACROSS THE NORTHERN PLAINS. THIS
SYSTEM WILL BEGIN TO AFFECT THE ROCKFORD/CHICAGO TERMINALS DURING
THE EVENING HOURS AS CIGS BEGIN TO COME DOWN AND SNOWFALL STARTING
LATE IN THE EVENING. EXPECT LIGHT ACCUMULATIONS WITH THIS SYSTEM...
AN INCH OR TWO...WITH IFR OR LOW END MVFR CONDITIONS RETURNING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* HIGH CONFIDENCE THAT CIGS WILL NOW REMAIN ABOVE 1500 FT INTO
THE DAYLIGHT HOURS.
* MEDIUM CONFIDENCE IN EXACT DEPARTURE TIME OF MORNING CLOUDS...BUT
HIGH CONFIDENCE THEY WILL BE OUT OF THE AREA BY 14Z.
* MEDIUM CONFIDENCE IN VISIBILITY TRENDS THROUGH 14Z.
* MEDIUM CONFIDENCE ON SNOW TIMING TONIGHT. HIGH CONFIDENCE IN AT
LEAST TEMPORARY VISIBILITY UNDER 4SM IN SNOW.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...MVFR POSSIBLE. GUSTS TO AROUND 30KT POSSIBLE.
SUNDAY...SLIGHT CHANCE OF SNOW...ELSE VFR.
MONDAY...VFR.
TUESDAY...MVFR WITH CHANCE OF RAIN.
WEDNESDAY...MVFR.
BMD/MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ745...7 AM FRIDAY TO 2 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* LOW CEILINGS GRADUALLY DEPARTING FROM NORTHWEST TO SOUTHEAST BY
OR SOON AFTER DAYBREAK.
* LOW VISIBILITY GRADUALLY IMPROVING.
* CHANCES FOR SNOW FRIDAY EVENING/NIGHT.
//DISCUSSION...UPDATED 06Z...
A SLOW MOVING COLD FRONT IS MOVING ACROSS THE MISSISSIPPI RIVER THIS
EVENING WITH CONDITIONS QUICKLY IMPROVING TO VFR BEHIND THE FRONT.
AHEAD OF THE FRONT...WIDESPREAD IFR/LIFR CONDITIONS PERSIST MAINLY
DUE TO LOW CIGS...WITH VARIABLE VSBY. VSBY SHOULD SHOW A GRADUAL
IMPROVING TREND OVER NEXT COUPLE HOURS AS WIND SPEEDS PICK UP
AHEAD OF THE FRONT TONIGHT...BUT CIGS WILL HOLD STEADY OR MAY FALL
SOME AS WEAK PRESSURE FALLS CONTINUE TO OVERSPREAD THE AREA. SKIES
SHOULD QUICKLY CLEAR IN THE EARLY MORNING HOURS...~06Z AT RFD AND
09-10Z FOR THE CHICAGO AREA TERMINALS...AS ANTICYCLONIC FLOW
MOVES ACROSS THE REGION BEHIND THE COLD FRONT.
MOST OF FRIDAY WILL HAVE RELATIVELY QUIET WEATHER CONDITIONS WITH
WESTERLY WINDS GRADUALLY BACKING TO THE SOUTHWEST THROUGH THE DAY AS
ANOTHER CLIPPER SYSTEM PUSHES EAST ACROSS THE NORTHERN PLAINS. THIS
SYSTEM WILL BEGIN TO AFFECT THE ROCKFORD/CHICAGO TERMINALS DURING
THE EVENING HOURS AS CIGS BEGIN TO COME DOWN AND SNOWFALL STARTING
LATE IN THE EVENING. EXPECT LIGHT ACCUMULATIONS WITH THIS SYSTEM...
AN INCH OR TWO...WITH IFR OR LOW END MVFR CONDITIONS RETURNING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE IN EXACT DEPARTURE TIME OF MVFR CLOUDS...BUT
HIGH CONFIDENCE THEY WILL BE OUT OF THE AREA BY 13Z.
* MEDIUM CONFIDENCE IN VISIBILITY REMAINING 5SM OR HIGHER THE
REMAINDER OF THE NIGHT.
* MEDIUM CONFIDENCE ON SNOW TIMING FRIDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...MVFR POSSIBLE. GUSTS TO AROUND 30KT POSSIBLE.
SUNDAY...SLIGHT CHANCE OF SNOW...ELSE VFR.
MONDAY...VFR.
TUESDAY...MVFR WITH CHANCE OF RAIN.
WEDNESDAY...MVFR.
BMD/MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN
CITY IN TIL 2 PM FRI.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SAT TO 6 PM SAT.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
536 AM CST FRI JAN 27 2012
.AVIATION...
VFR WX IS EXPECTED THROUGH 20Z/27 WITH HIGH AND MID LEVEL CLOUDS.
AFT 20Z/27 CIGS WILL SLOWLY LOWER TO JUST ABOVE MVFR. TOP DOWN
SATURATION OF THE ATMOSPHERE WILL OCCUR FROM 21Z/27 TO 03Z/28 WITH
PRECIPITATION TURNING TO -SN AS THE LOWER ATMOSPHERE COOLS. ROUGHLY A
6 HR PERIOD OF MVFR CONDITIONS ARE EXPECTED THAT MAY BRIEFLY GO TO
IFR. CONDITIONS SHOULD IMPROVE AGAIN TO VFR 03Z/28 TO 09Z/28.
..08..
&&
.PREV DISCUSSION... /ISSUED 312 AM CST FRI JAN 27 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS A STORM SYSTEM OVER THE EASTERN GREAT LAKES
MOVING INTO NEW ENGLAND. WEAK LOWS WERE LOCATED NEAR KBIS AND
KPHP. A WARM FRONT RAN FROM THE KPHP LOW TO NEAR KYKN AND THEN
SOUTH INTO EASTERN NEBRASKA. DEW POINTS WERE GENERALLY IN THE 20S
AND 30S ACROSS THE MIDWEST WITH A POCKET OF TEENS IN THE PLAINS.
SATELLITE TRENDS SHOW HIGH CLOUDS MOVING EAST TOWARD THE
MISSISSIPPI RIVER WITH MID AND SOME LOW CLOUDS IN THE PLAINS.
RADAR HAS VERY LIGHT PRECIPITATION OCCURRING IN THE CENTRAL AND
NORTHERN PLAINS.
SHORT TERM...TODAY AND TONIGHT...
THE KEY TO EVERYTHING LATER TODAY AND TONIGHT WILL BE WHEN DOES
SATURATION OCCUR. VERIFICATION OF THE MODELS THROUGH 06Z SHOW THEY
ARE WAY OVERDONE ON THE AMOUNT OF QPF. ADDITIONALLY...THEY ALL
INITIALIZED TOO MOIST IN THE LOW LEVELS AND HAD THE STRENGTH OF THE
PLAINS SFC RIDGE TOO STRONG. ALL THIS PLAYS SIGNIFICANTLY INTO
PRECIPITATION AMOUNTS IN THE NEXT 24 HRS.
OVERALL FORCING AND 850-700MB CONDENSATION PRESSURE DEFICITS FROM
THE RUC HAVE BEEN QUITE USEFUL IN DEPICTING WHERE PRECIPITATION
HAS BEEN OCCURRING IN THE PLAINS SO FAR. HOWEVER...IT TOO IS A BIT
OVERLY MOIST ON ITS INITIALIZATION AT 06Z.
THE MORNING HOURS WILL BE DRY WITH INCREASING CLOUDS. DURING THIS
TIME TEMPERATURES WILL RESPOND REASONABLE WELL TO THE WAA THAT
WILL BE OCCURRING AND ALLOW TEMPERATURES TO GET ABOVE NORMAL.
CAREFUL EXTRAPOLATION OF THE 12 HR RUC FCST SUGGESTS PRECIPITATION
ADVECTING OR DEVELOPING ROUGHLY WEST OF A DUBUQUE TO KEOKUK LINE
DURING THE FIRST HALF OF THE AFTERNOON. FCST SOUNDINGS FROM THE
RUC AND OTHER MODELS SUGGEST THAT MUCH OF THE FORCING WILL GO INTO
SATURATION. THE WARM TEMPERATURES INDICATE THAT THE PRECIPITATION
SHOULD INITIALLY START OUT AS RAIN. HOWEVER...EVAPORATIVE COOLING
WILL QUICKLY DROP THE LOWER ATMOSPHERE BELOW FREEZING. SO THE
PRECIPITATION WILL START OUT AS RAIN AND QUICKLY CHANGE TO SNOW
WITH A BRIEF PERIOD OF A MIX.
BY 00Z...6 PM...A WAA WING OF PRECIPITATION SHOULD COVER ALL BUT
THE FAR EASTERN REACHES OF THE CWFA. SNOW AMOUNTS BY EARLY EVENING
WILL RANGE FROM ZERO TO A DUSTING.
BASED ON THE OVERALL MOVEMENT OF THE FORCING...PRECIPITATION
SHOULD LAST ABOUT 6-9 HRS AT ANY ONE LOCATION ONCE IT BEGINS.
PRECIPITATION SHOULD BE WIDESPREAD ACROSS THE CWFA DURING THE
EARLY EVENING WITH IT ENDING FROM WEST TO EAST AFTER 9 PM.
PRECIPITATION SHOULD LINGER PAST MIDNIGHT OVER ROUGHLY THE EASTERN
HALF OF THE CWFA BEFORE ENDING BY SUNRISE SATURDAY.
OVERALL SNOW AMOUNTS FOR THIS EVENT SHOULD RANGE FROM A DUSTING TO
JUST OVER ONE HALF INCH.
.08..
LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
NORTHWEST FLOW PATTERN WILL DOMINATE INTO MON. CLIPPER SYSTEM TO PASS
MAINLY TO OUR NORTH SAT NGT WITH SMALL CHC OF -SN WITH WARM
ADVECTION WING FAR N/NE COUNTIES. BETTER CHCS WILL RESIDE
FARTHER NORTH ACROSS PORTIONS OF MN AND WI ALONG AND LEFT OF THE
TRACK IN THE COLDER AIR. AS IT PASSES TO OUR N/E SAT NGT IT WILL SEND
COLD FRONT DOWN THROUGH REGION RESULTING IN COLDER TEMPS (NEAR TO
A LITTLE BELOW NORMAL) ON SUNDAY. NEXT WEAK CLIPPER SYSTEM
AND ATTENDANT WARM ADVECTION WING LOOKS TO PASS WELL NORTH OF REGION
SUN NGT INTO MON. STRENGTHENING SOUTHERLY SFC FLOW WILL BRING WELL
ABOVE NORMALS TEMPS BACK INTO REGION. HAVE BUMPED UP HIGHS SEVERAL
DEGS ON MON... BUT IF 00Z GFS AND HI-RES ECMWF VERIFY ON MIXING DEPTH
AND THERMAL FIELDS THEN WOULD NEED TO RAISE FURTHER WITH BOTH
SUPPORTIVE OF M/U 40S IN THE NORTH TO AROUND 57F IN THE FAR SOUTH.
TUE-THU... ZONAL FLOW LOOKS TO DOMINATE ACROSS MUCH OF THE CONUS WITH
TEMPS ABOVE NORMAL IN MP AIRMASS. MODELS STILL VARY ON EVOLUTION
OF PACIFIC SHORTWAVE ON TUE WITH THE ECMWF AND GEM MORE PROGRESSIVE
AND NORTHERLY WHILE THE GFS AND UKMET ARE MUCH SLOWER AND MORE
SOUTHERLY. DPROG/DT OF GFS SHOWS CONSIDERABLE RUN TO RUN VARIANCE WHILE
ECMWF MORE STABLE... AND THUS FAVORED. LOW LEVEL MOISTURE LOOKS
FAIRLY SHALLOW AND TRANSPORT VECTORS VEER IN TIME ON TUE SHUNTING
BETTER LOW LEVEL MOISTURE TO OUR S/E. HAVE THEREFORE TRIMMED BACK POPS
TO MOSTLY SLIGHT CHC. PATTERN LOOKS TO SHIFT BACK TO HIGHLY AMPLIFIED
ONE BY LATE WEEK INTO NEXT WEEKEND WITH RETURN OF COLDER AIR. DURING
THIS TRANSITION THERE WILL BE AT LEAST A COUPLE OF PCPN CHCS (RAIN/SNOW)
THU-SAT. ..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
607 AM CST FRI JAN 27 2012
.AVIATION...
FOR THE 12Z TAF ISSUANCE...
VERY STRONG NORTH WINDS WILL AFFECT ALL THREE TERMINALS TODAY
(GCK, DDC, HYS) AS A COLD FRONT MOVES SOUTH ACROSS THE CENTRAL
PLAINS. THE STRONGEST WINDS WILL OCCUR BETWEEN ROUGHLY 17Z AND 21Z
WHICH IS WHEN 30 TO 35 KNOTS SUSTAINED WILL BE OCCURRING. A FEW
WIND GUSTS IN THE 45 TO 50 KNOT RANGE WILL ALSO BE POSSIBLE. VFR
CONDITIONS ARE EXPECTED TO PREVAIL WITH THE PASSAGE OF THE COLD
FRONT ACROSS SOUTHWEST KANSAS. -UMSCHEID
&&
.PREV DISCUSSION... /ISSUED 324 AM CST FRI JAN 27 2012/
SYNOPSIS...
IN APPLYING THE FORECAST FUNNEL, ONE WOULD START WITH THE 27.00Z 300
HPA SYNOPTIC MAP. A 100 KT JET EXTENDED FROM KMFR TO KLBF. THIS JET
WAS WELL UPSTREAM OF A HIGHLY AMPLIFIED MERIDIONAL TROUGH AXIS THAT
EXTENDED FROM ONTARIO INTO THE GULF OF MEXICO. A FASTER 135 TO 140 KT
JET LOCATED EAST OF THIS TROUGH AXIS ACROSS THE EASTERN UNITED STATES.
AT 500 HPA, A SHORTWAVE TROUGH WAS MOVING ACROSS THE NORTHERN ROCKIES.
THIS UPPER LEVEL FEATURE WAS USHERING IN A SURFACE COLD FRONT ACROSS
THE NORTHERN PLAINS AND INTO WYOMING. NOTHING TOO OUT OF THE ORDINARY WAS
OBSERVED AT 700 AND 850 HPA ACROSS THE CENTRAL PLAINS EXCEPT A DRY THERMODYNAMIC
PROFILE. -SUGDEN
DISCUSSION...
DAYS 1-2...
TODAY:
FORECAST SOUNDINGS FROM THE 27.00Z GFS AND 27.00Z NAM BOTH AGREE ON
RAPID SATURATION BETWEEN 600 AND 400 HPA IN ASSOCIATION WITH MID LEVEL
MOISTURE ADVECTION AHEAD OF AN APPROACHING UPPER LEVEL SHORTWAVE TROUGH
THIS MORNING. BELOW 600 HPA, ALL MODELS SHOW THE ATMOSPHERIC PROFILE
BECOMING MIXED (PARTICULARLY BELOW 800 HPA) AND AS A RESULT IS RELATIVELY
DRY. WITH THE EXCEPTION OF THE 27.00Z GFS, ALL MODELS BASICALLY HAVE
NO QPF ACROSS SOUTHWEST KANSAS TODAY. ALSO CHECKED THE ARW/NMM/HRRR
WHICH PAINT AN ALMOST NEGLIGIBLE QPF SIGNAL. AS A RESULT, HAVE REDUCED
POPS TO BELOW 15 PERCENT. SOME VIRGA IS POSSIBLE THIS MORNING BUT OTHER
THAN THAT, THE FORECAST WILL REMAIN DRY FOR TODAY.
SECOND SENSIBLE WEATHER CONCERN AND RATHER THE MOST SIGNIFICANT IS WINDS.
AS THE ABOVE MENTIONED SHORTWAVE TROUGH MOVES ACROSS KANSAS, THIS FEATURE
WILL PUSH A SURFACE COLD FRONT ACROSS THE REGION THIS MORNING. IN THE
WAKE OF THE FRONT, A TIGHT PRESSURE GRADIENT AND MIXING FROM ON AVERAGE
800 HPA TO THE SURFACE WILL RESULT IN MOMENTUM TRANSFER FROM THE TOP
OF THE BOUNDARY LAYER TO THE GROUND. BUFKIT SOUNDINGS SHOW ABOUT 40
KT AT THE TOP OF THE MIXING LAYER. AS WITH THE PREVIOUS DAY SHIFT, I
HAVE UTILIZED THE MIXED LAYER WIND SMART TOOL WHICH BROUGHT IT REASONABLE
WINDS SPEEDS INTO THE GRIDS. MOS/LAMP GUIDANCE ALSO SUGGESTS SIMILAR
WIND MAGNITUDE AS OUTPUTTED BY TOOL. THE ONGOING NPW LOOKS VERY REASONABLE
ALTHOUGH I DID ADJUST THE START TIME EARLIER AS THE HRRR MODEL IS SUGGESTING
NEAR CRITERIA WIND SPEEDS AT THE END OF THE MODEL RUN (EARLIER). WINDS
AROUND 29-33 KT WITH GUSTS TO 40-45 KT ARE FORECAST TODAY. WINDS WILL
DECREASE SIGNIFICANTLY TOWARDS SUNSET.
TONIGHT:
HIGH PRESSURE WILL SLIDE ACROSS KANSAS TONIGHT AND INTO TOMORROW MORNING.
FORECAST SOUNDINGS SHOW RAPID DRYING IN THE MID LEVELS AFTER 00Z. WITH
CLEARING SKIES AND RELATIVELY LIGHT WINDS, AM EXPECTING COOL OVERNIGHT
LOWS WITH TEENS TO LOW 20S DEG F ACROSS MUCH OF THE REGION. SUBSIDENCE
AND HIGH PRESSURE IN THE WAKE OF THE DEPARTING TROUGH WILL KEEP POPS
AT ZERO BY 06Z TONIGHT.
SATURDAY/SATURDAY NIGHT:
EXTREMELY QUIET WEATHER IS EXPECTED AS NORTHWESTERLY FLOW ALOFT PREVAILS
ACROSS THE SUNFLOWER STATE THROUGH THE BEGINNING OF THE WEEKEND. MUCH
WEAKER WESTERLY TO NORTHWESTERLY WINDS AROUND 10 TO 15 KT ARE EXPECTED
SATURDAY. TEMPERATURES WILL BE FAIRLY SEASONABLE TO SLIGHT ABOVE
WITH MID TO UPPER 40S DEG F EXPECTED. SKIES SHOULD BE FAIRLY
CLEAR. LOWS INTO SUNDAY MORNING ARE EXPECTED TO BE NEAR NORMAL...LOW
20S DEG F. -SUGDEN
DAYS 3-7...
A PROGRESSIVE, ZONAL SYNOPTIC SCALE PATTERN IS EXPECTED TO PREVAIL THROUGH
THE MEDIUM RANGE YIELDING WEAK COLD FRONT PASSAGES AND AN OVERALL CONTINUED
ABOVE-AVERAGE TEMPERATURE FORECAST.
A LEE TROUGH WILL DEVELOP SUNDAY AS AN UPPER LEVEL TROUGH BEGINS TO
ENTER THE PACIFIC NORTHWEST REGION. REMNANT, COOL POLAR AIRMASS OVER
THE CENTRAL CONUS WILL LOSE ITS GRIP WITH INCREASING LOW LEVEL THICKNESSES
AND SUBSEQUENT WARMER TEMPERATURES OVER THE WESTERN PLAINS. HIGHS SUNDAY
SHOULD WARM WELL INTO THE 50S AND HAVE INCREASED THE FORECAST HIGHS
ABOUT 2 TO 3 DEGREES ON AVERAGE ACROSS THE DDC FORECAST AREA.
MONDAY CERTAINLY LOOKS TO BE A WARM DAY WITH THE LEE TROUGH OVER EASTERN
COLORADO AND ADJACENT WESTERN KANSAS DOWN TO ABOUT 1002-1004MB. DEPENDING
ON THE DEGREE OF BOUNDARY LAYER MIXING, A VERY WARM DAY COULD RESULT...ESPECIALLY
ACROSS THE SOUTHWESTERN COUNTIES (HIGHER ELEVATION RESULTING IN BETTER
POTENTIAL FOR DEEPER MIXING). THE ALLBLEND GUIDANCE GIVES HIGHS OF 59-60F
FOR MUCH OF THE FORECAST AREA BUT SOME MID 60S CANNOT BE RULED OUT IN
THIS VERY WARM PATTERN AHEAD OF A LOW AMPLITUDE ZONAL SHORTWAVE TROUGH.
THIS AFOREMENTIONED TROUGH WILL MOVE FAST ACROSS THE CENTRAL PLAINS
MONDAY NIGHT AND TUESDAY SHOULD BE A BIT COOLER...YET STILL QUITE A
BIT ABOVE THE CLIMATOLOGICAL AVERAGE OF LOWER-MID 40S FOR SOUTHWEST
KANSAS TO END THE MONTH OF JANUARY. AFTER THAT...THERE IS SOME UNCERTAINTY
IN HOW THE PATTERN WILL EVOLVE. THE GFS SHOWS AMPLIFICATION TAKING PLACE
QUICKLY OVER THE WESTERN CONUS WITH A RIDGE AXIS OVER THE WEST COAST
AND SUBSEQUENT TROUGH OVER THE CENTRAL CONUS. THIS IS A COOLER PATTERN,
HOWEVER THE NEW ECMWF MODEL SHOWS A MUCH WARMER SCENARIO FOR MID-WEEK
WITH A MUCH LOWER AMPLITUDE RIDGE-TROUGH SETUP OVER THE WESTERN AND
CENTRAL CONUS. THE ECMWF MODEL DOES INDEED AMPLIFY THE SYNOPTIC SCALE
PATTERN RATHER SUBSTANTIALLY BY THURSDAY, RESULTING IN A MEAN TROUGH/LOWER
HEIGHTS OVER THE CENTRAL CONUS...SO THE ABOVE/MUCH ABOVE TEMPERATURES
WE WILL BE SEEING SUNDAY THROUGH WEDNESDAY MAY END BY THURSDAY- FRIDAY
OF NEXT WEEK (FEB 2-3) DEPENDING ON HOW THE AMPLIFICATION OF THE LARGE
SCALE PATTERN EVOLVES OVER THE CONUS. -UMSCHEID
AVIATION...
FOR THE 06Z TAF ISSUANCE...SOUTH TO SOUTHEAST WINDS AT 8 TO 15 KNOTS
WILL PERSIST AT THE TAF SITES THROUGH ABOUT 10Z. THE WINDS COULD OCCASIONALLY
BE GUSTY TO 20 KNOTS AS WELL. AFTER 10Z THE WINDS WILL DIMINISH AND
SWITCH TO THE SOUTHWEST AS A LOW PRESSURE TROUGH MOVES INTO THE AREA
FROM EASTERN COLORADO. A STRONG COLD FRONT WILL PUSH THROUGH WESTERN
KANSAS BETWEEN 12Z AND 14Z. WINDS BEHIND THE FRONT WILL INCREASE FROM
THE NORTH AT 25 TO 35 KNOTS AND CONTINUE INTO THE EARLY AFTERNOON HOURS
BEFORE DIMINISHING SOMEWHAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 18 49 21 / 10 0 0 0
GCK 45 18 47 20 / 10 0 0 0
EHA 45 19 49 23 / 10 0 0 0
LBL 46 18 49 21 / 10 0 0 0
HYS 47 18 47 20 / 10 0 0 0
P28 53 20 49 23 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ030-
031-043>046-061>066-074>081-084>090.
&&
$$
FN99/99/25
AREA FORECAST DISCUSSION
NWS GOODLAND KS
446 AM MST FRI JAN 27 2012
.DISCUSSION...
200 AM MST FRI JAN 27 2012
SHORT TERM...TODAY-SUNDAY NIGHT...COLD FRONT AN HOUR OR SO AWAY
FROM ENTERING THE FORECAST AREA. AS PREVIOUS SHIFTS HAVE
MENTIONED ADVISORY CRITERIA WINDS TO MOVE IN FROM WEST TO EAST
WITH SUSTAINED WINDS AROUND 30-35 MPH WITH GUSTS AROUND 50 MPH.
HIGH TEMPERATURES 35 TO 40 WEST OF THE CO/KS BORDER...LOW TO MID
40S EAST WITH WARMEST READINGS IN THE NORTON AND HILL CITY AREAS.
VERY DRY AIR MOVES IN TONIGHT AND AROUND 06Z WINDS MAY REALLY DROP
OFF FOR A FEW HOURS BEFORE INCREASING FROM THE SOUTHWEST WHICH
SHOULD TEND TO STABILIZE TEMPS A BIT. ITS THAT FEW HOURS WHERE THE
COLDEST READINGS EXPECTED WITH LOWS GENERALLY 10-15 DEGREES. DRY
AIR REMAINS OVER THE AREA SATURDAY WITH AFTERNOON HIGHS IN THE MID
40S. SHOULD HAVE NORTHWEST WINDS OF 15-20 MPH WITH HIGHER GUSTS
GENERALLY NORTH OF THE INTERSTATE AS PRESSURE GRADIENT INCREASES.
FOR SUNDAY MILD TEMPERATURES RETURN TO THE AREA AS BROAD UPPER
RIDGING SLOWLY MOVES IN FROM THE WEST. HIGH TEMPERATURES GENERALLY
IN THE MID 50S.
007
LONG TERM...MONDAY THROUGH THURSDAY
AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE TRI-STATE AREA TUESDAY
AND AGAIN ON WEDNESDAY. DUE TO UNCERTAINTIES REGARDING MOISTURE AND
JET SUPPORT WILL GO WITH THE DRY CONSENSUS MODEL OUTPUT.
TEMPERATURES THROUGH THE PERIOD WILL BE ABOVE NORMAL. THE WARMEST
TEMPERATURES FOR THE PERIOD WILL BE MONDAY PRIOR TO A COLD FRONT
MOVING THROUGH THE AREA MONDAY NIGHT.
JTL
&&
.AVIATION...
436 AM MST FRI JAN 27 2012
VFR CONDITIONS EXPECTED FOR THE 12Z TAFS. COLD FRONT CURRENTLY
WORKING ITS WAY THROUGH NORTHEAST COLORADO AND SOUTHWEST NEBRASKA.
AM THINKING THE FRONT WILL MOVE THROUGH THE TAFS SITES DURING THE
12Z TO 15Z TIME FRAME THIS MORNING...MOVING THROUGH KGLD CLOSER TO
12Z AND KMCK CLOSER TO 15Z. NAM SOUNDINGS/CROSS SECTIONS AND EARLIER
HRRR HAVE BEEN INDICATING A PERIOD OF MVFR CEILINGS AS THE FRONT
MOVES THROUGH. LATEST HRRR HAS BACKED OFF THE MVFR
CEILINGS...SHOWING LOW VFR CEILINGS INSTEAD WHICH IS MORE IN LINE
WITH THE LATEST OBSERVATIONS. AS SUCH HAVE LOW VFR CEILINGS
FORECAST AS THE FRONT MOVES THROUGH. BEHIND THE FRONT WINDS WILL
INCREASE QUICKLY AND REMAIN STRONG THROUGH MUCH OF THE AFTERNOON.
THE WINDS WILL BACK OFF AS TEMPERATURES COOL DURING THE EVENING.
JTL
&&
.FIRE WEATHER...
200 AM MST FRI JAN 27 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN POSSIBLE SATURDAY
AFTERNOON. AFTERNOON RH VALUES TO DROP JUST BELOW 20 PERCENT WITH
NORTHWEST WINDS OF 15 TO 20 MPH WITH HIGHER GUSTS. LATER SHIFTS
CAN RE-EVALUATE THE NEED FOR A FIRE WEATHER HIGHLITE.
007
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 8 AM MST /9 AM CST/ THIS MORNING TO 5 PM MST
/6 PM CST/ THIS AFTERNOON FOR KSZ001>004-013>016-027>029-
041-042.
NE...WIND ADVISORY FROM 8 AM MST /9 AM CST/ THIS MORNING TO 5 PM MST
/6 PM CST/ THIS AFTERNOON FOR NEZ079>081.
CO...WIND ADVISORY FROM 8 AM THIS MORNING TO 5 PM MST THIS AFTERNOON
FOR COZ090>092.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1041 AM EST FRI JAN 27 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST PROMPTING A SECONDARY
COASTAL LOW TO DEEPEN ALONG THE NEW ENGLAND COAST THIS
AFTERNOON. THE LOW WILL EXIT INTO THE CANADIAN MARITIMES TONIGHT.
ANOTHER LOW WILL TRACK THROUGH SOUTHERN CANADA SATURDAY NIGHT
WITH A WEAK COLD FRONT CROSSING NORTHERN NEW ENGLAND. ANOTHER
FRONT WILL CROSS NEW ENGLAND SUNDAY NIGHT WITH COLDER TEMPERATURES
BEHIND IT. A WARM FRONT WILL LIFT NORTHWARD INTO NORTHERN NEW
ENGLAND TUESDAY NIGHT AND LOW PRESSURE WILL TRACK ALONG THE WARM
FRONT ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
FREEZING LINE CONTINUES TO CREEP NORTH INTO CENTRAL GRAFTON AND
CARROLL COUNTIES BUT REMAINS MIDWAY THROUGH CUMBERLAND COUNTY AND
SOUTH OF AUGUSTA. WINDS ARE EASTERLY ALONG THE COAST AND ROCKLAND
IS GUSTING TO NEAR 30 MPH. THE BEST PRESSURE FALLS ARE NEAR
BEVERLY MASSACHUSETTS AND IT APPEARS THIS IS WHERE THE SURFACE LOW
WILL REDEVELOP. THIS WILL KEEP THE COLD AIR OVER OUR AREA LONGER.
WILL NEED TO KEEP AN EYE ON THE ENDING TIMES OF THE ADVISORIES AND
WARNINGS. THE HRRR MODEL INDICATES PRECIPITATION WILL BE WINDING
DOWN BY NOON...BUT IF COLD AIR HANGS ON AND LIGHT PRECIPITATION
CONTINUES WE MAY NEED TO EXTEND THE ADVISORY FOR A COUPLE HOURS.
RADAR IMAGERY IS ENCOURAGING WITH A RELATIVELY ECHO-FREE AREA
HEADED OUR WAY. ADJUSTED HIGH TEMPERATURES DOWN A COUPLE OF
DEGREES FOR THIS UPDATE.
$$
PREVIOUS UPDATE... HAVE UPDATED THE FORECASTS AND GRIDS TO
ACCOUNT FOR CURRENT CONDITIONS WITH THE ANTICIPATED CHANGEOVER IN
FULL SWING ACROSS SOUTHERN ZONES. HAVE REMOVED THE COAST FROM THE
WINTER WEATHER ADVISORIES AS TEMPERATURES HAVE CLIMBED TO AT OR
ABOVE FREEZING IN MOST LOCATIONS AS THE ONSHORE EASTERLIES
CONTINUE OFF THE BRINK. OVER SOUTHERN NEW HAMPSHIRE AND INTERIOR
SOUTHWEST MAINE...WARM AIR HAS SUFFICIENTLY ENTERED THE
REGION...BOTH AT THE SURFACE AND ALOFT TO CHANGE THE P TYPE TO
RAIN.
LATEST SURFACE ANALYSIS CONTINUES TO SHOW THE BEST PRESSURE FALLS
ALONG THE MASSACHUSETTS COASTLINE WHILE LOW PRESSURE LINGERS BACK
IN WRN PA. WINDS HAVE BACKED OVER THE LAST HOUR ALONG THE COAST.
THIS TREND WILL BE MONITORED VERY CLOSELY IN THE EVENT THE
SECONDARY LOW DEVELOPS FURTHER SOUTH NEAR MASSACHUSETTS...INSTEAD
OF THE MAINE COASTLINE. THIS WOULD HAVE RAMIFICATIONS TO THE LOW
LEVEL THERMAL PROFILE AND P TYPES FOR TODAY...BRINGING A SLIGHTLY
COLDER SOLUTION TO THIS EVENT OVER CENTRAL AND NORTHERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
AFTER SOME PCPN OVER EASTERN AREAS EARLY...CLEARING IS EXPECTED
THIS EVENING AS THE SURFACE LOW PROGRESSES INTO THE CANADIAN
MARITIMES. THIS WILL BE FOLLOWED BY A WEAK RIDGE OF HIGH PRESSURE
LATE TONIGHT. HOWEVER...SOME HIGH...THIN CLOUDINESS WILL ALREADY
BE INVADING THE SKY BY MIDDAY SATURDAY AS A WEAK TROUGH OF LOW
PRESSURE QUICKLY APPROACHES NORTHERN NEW ENGLAND. WITH DRY
ATMOSPHERE IN PLACE IN THE LOWER LEVELS...WE EXPECT ANY PCPN TO
HOLD OFF UNTIL AFTER DARK.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
OVER THE OUTLOOK PERIOD FAST MOVING CLIPPERS WITH VERY LIMITED
MOISTURE WILL BE MOVING THROUGH A RATHER ZONAL WESTERLY FLOW
ALLOWING EXCHANGES IN AIR MASSES ABOUT EVERY 48 HRS. TEMPS WILL
GENERALLY BE AVERAGING ABOVE NORMAL THROUGH MOST OF THE PERIOD.
WITH THAT GENERAL OUTLOOK IN MIND...MORE SPECIFICALLY...A RIDGE OF
HIGH PRESSURE CROSSES THE AREA ON SATURDAY WITH WARMER
TEMPERATURES AND DRY CONDITIONS.
A FAST MOVING CLIPPER MOVES EAST THROUGH ONTARIO AND INTO QUEBEC
LATE SATURDAY INTO SATURDAY NIGHT...SPREADING SCATTERED SNOW
SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND WESTERN MAINE. A
COLD FRONT WILL PUSH THROUGH AS WELL WITH COLDER TEMPERATURES AND
GUSTY WEST WINDS BEHIND IT.
A WEAK RIDGE OF PRESSURE SETTLES OVER THE AREA SUNDAY BUT IS
QUICKLY FOLLOWED BY ANOTHER FAST MOVING CLIPPER THAT WILL MOVE
ACROSS NEW ENGLAND SUNDAY NIGHT WITH A WEAK SURFACE LOW TRACKING
THROUGH SOUTHERN QUEBEC. A FEW MORE LIGHT SNOW SHOWERS WILL BE
POSSIBLE MAINLY IN THE MOUNTAINS. SEASONABLY COLD AIR WILL MOVE IN
FOR MONDAY.
THE FAST FLOW ALOFT CONTINUES THROUGH THE WEEK WITH WAVE AFTER
WAVE CROSSING THROUGH THE FLOW. ANOTHER WAVE APPROACHES ON TUESDAY
WITH A WARM FRONT LIFTING NORTHWARD INTO CENTRAL PARTS OF NEW
HAMPSHIRE AND MAINE BY TUESDAY NIGHT INTO WEDNESDAY. THIS MAY LEAD
TO SOME LIGHT SNOW BUT OVERALL FORCING LOOKS WEAK UNTIL WEDNESDAY
WHEN SURFACE LOW PRESSURE TRACKS EASTWARD ALONG THE WARM FRONT.
BEST PRECIPITATION CHANCES WILL BE FARTHER TO THE NORTH. WARM AIR
IN PLACE SOUTH OF THE WARM FRONT WILL YIELD MOSTLY RAIN AS
PRECIPITATION TYPE...WHILE NORTH OF THE FRONT SNOW IS MORE
LIKELY.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
MAINLY LIFR CONDITIONS...IMPROVING TO VFR THIS EVENING WITH THE
PASSAGE OF THE SURFACE LOW AND A WIND SWITCH TO THE WEST.
LONG TERM...
MOSTLY VFR CONDITIONS EXPECTED. MOST LIKELY TIMES FOR
FLIGHT RESTRICTIONS WILL BE SUNDAY NIGHT AND AGAIN TUESDAY THROUGH
WEDNESDAY.
&&
.MARINE...
SHORT TERM...
HAVE ISSUED A GALE WARNING FOR THE OUTER WATERS THROUGH TONIGHT AS
SURFACE LOW INTENSIFIES...PULLS TO OUR EAST...AND INCREASES THE
GRADIENT AS WELL AS THE COLD AIR ADVECTION.
LONG TERM...
MAY SEE WINDS REACH 30 OR 35 KT BEHIND A COLD FRONT ON
SATURDAY NIGHT. ANOTHER FAST MOVING FRONT WILL CROSS THE WATERS
SUNDAY NIGHT WITH GUSTY WINDS BEHIND IT AS WELL.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ019>022.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ012>014.
NH...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NHZ005-006.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR ANZ151-153.
GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ150-152-154.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS GRAY ME
720 AM EST FRI JAN 27 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST PROMPTING A SECONDARY COASTAL
LOW TO DEEPEN ALONG THE NEW ENGLAND COAST THIS AFTERNOON. THE LOW
WILL EXIT INTO THE CANADIAN MARITIMES TONIGHT. ANOTHER LOW WILL
TRACK THROUGH SOUTHERN CANADA ON SATURDAY NIGHT WITH A WEAK COLD
FRONT CROSSING NORTHERN NEW ENGLAND. ANOTHER FRONT WILL CROSS NEW
ENGLAND SUNDAY NIGHT WITH COLDER TEMPERATURES BEHIND IT. A WARM
FRONT WILL LIFT NORTHWARD INTO NORTHERN NEW ENGLAND TUESDAY NIGHT
AND LOW PRESSURE WILL TRACK ALONG THE WARM FRONT ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED THE FORECASTS AND GRIDS TO ACCOUNT FOR CURRENT
CONDITIONS WITH THE ANTICIPATED CHANGEOVER IN FULL SWING ACROSS
SOUTHERN ZONES. HAVE REMOVED THE COAST FROM THE WINTER WEATHER
ADVISORIES AS TEMPERATURES HAVE CLIMBED TO AT OR ABOVE FREEZING IN
MOST LOCATIONS AS THE ONSHORE EASTERLIES CONTINUE OFF THE BRINK.
OVER SOUTHERN NEW HAMPSHIRE AND INTERIOR SOUTHWEST
MAINE...WARM AIR HAS SUFFICIENTLY ENTERED THE REGION...BOTH AT THE
SURFACE AND ALOFT TO CHANGE THE PTYPE TO RAIN.
LATEST SURFACE ANALYSIS CONTINUES TO SHOW THE BEST PRESSURE FALLS
ALONG THE MASSACHUSETTS COASTLINE WHILE LOW PRESSURE LINGERS BACK
IN WRN PA. WINDS HAVE BACKED OVER THE LAST HOUR ALONG THE COAST.
THIS TREND WILL BE MONITORED VERY CLOSELY IN THE EVENT THE
SECONDARY LOW DEVELOPS FURTHER SOUTH NEAR MASSACHUSETTS...INSTEAD
OF THE MAINE COASTLINE. THIS WOULD HAVE RAMIFICATIONS TO THE LOW
LEVEL THERMAL PROFILE AND PTYPES FOR TODAY...BRINGING A SLIGHTLY COLDER
SOLUTION TO THIS EVENT OVER CENTRAL AND NORTHERN AREAS.
PREV DISC...
00Z SOUNDING AT GYX REMAINS VERY DRY IN THE LOWER LEVELS.
THIS COOL/DRY AIR IS ENTRENCHED MORE THAN EVEN THE COLDEST GFS
SCENARIO HAS TO OFFER. THIS HAS KEPT PCPN IN THE FORM OF SNOW FOR
A LONGER PERIOD ACROSS SOUTHERN MAINE AND NEW HAMPSHIRE.
LATEST HRRR RUN PUSHES THE PCPN TO QUICKLY AND AGRESSIVELY INTO
THIS DRY AIR. HOWEVER...ATMOSPHERE WILL SATURDAY OVER THE NEXT
HOUR OR TWO OVER NORTHERN PORTIONS OF THE FORECAST AREA.
MAIN BAND OF STEADY PCPN WILL CONTINUE TO MOVE NORTHWARD OUT OF
SOUTHERN NEW HAMPSHIRE OVER THE NEXT FEW HOURS. PTYPE WILL
TRANSITION FROM ALL SNOW TO SLEET AND FREEZING RAIN OVER
SOUTHERNMOST NH AND FAR SOUTHWEST MAINE OVER THE NEXT HOUR OR TWO
AS WARM AIR ARRIVES BOTH IN THE BOUNDRY LAYER AND ALOFT. PTYPE
WILL SWITCH TO RAIN RIGHT ALONG THE COAST AFTER A QUICK INCH OR
TWO HAS FALLEN.
MADE SOME MINOR ADJUSTMENTS TO THE SNOWFALL MAP FOR THE WEB TO
SMOOTH AND MODIFY SOME OF THE DATA. ALL WARNINGS AND ADVISORIES
WILL REMAIN IN PLACE THROUGH 21Z.
TIMING OF CHANGEOVER AND STEADY PCPN APPEARS TO BE ON TRACK. MADE
ONLY MINOR ADJUSTMENTS TO THE GRIDS. MAY NEED TO ADDRESS THE
MARINE FCST WITH GALES SHORTLY.
FAVORED COOLER MAV TEMPS FOR TODAYS MAXES.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AFTER SOME PCPN OVER EASTERN AREAS EARLY...CLEARING IS EXPECTED
THIS EVENING AS THE SURFACE LOW PROGRESSES INTO THE CANADIAN
MARITIMES. THIS WILL BE FOLLOWED BY A WEAK RIDGE OF HIGH PRESSURE
LATE TONIGHT. HOWEVER...SOME HIGH...THIN CLOUDINESS WILL ALREADY
BE INVADING THE SKY BY MIDDAY SATURDAY AS A WEAK TROUGH OF LOW
PRESSURE QUICKLY APPROACHES NORTHERN NEW ENGLAND. WITH DRY
ATMOSPHERE IN PLACE IN THE LOWER LEVELS...WE EXPECT ANY PCPN TO
HOLD OFF UNTIL AFTER DARK.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
OVER THE OUTLOOK PERIOD FAST MOVING CLIPPERS WITH VERY LIMITED
MOISTURE WILL BE MOVING THROUGH A RATHER ZONAL WESTERLY FLOW ALLOWING
EXCHANGES IN AIR MASSES ABOUT EVERY 48 HRS. TEMPS WILL GENERALLY
BE AVERAGING ABOVE NORMAL THROUGH MOST OF THE PERIOD.
WITH THAT GENERAL OUTLLOK IN MIND..MORE SPECIFICALLY...A RIDGE OF
HIGH PRESSURE CROSSES THE AREA ON SATURDAY WITH WARMER
TEMPERATURES AND DRY CONDITIONS.
A FAST MOVING CLIPPER MOVES EAST THROUGH ONTARIO AND INTO QUEBEC
LATE SATURDAY INTO SATURDAY NIGHT... SPREADING SCATTERED SNOW
SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND WESTERN MAINE.
A COLD FRONT WILL PUSH THROUGH AS WELL WITH COLDER TEMPERATURES
AND GUSTY WEST WINDS BEHIND IT.
A WEAK RIDGE OF PRES SETTLES OVER THE AREA SUNDAY BUT QUICKLY
FOLLOWED BY ANOTHER FAST MOVING CLIPPER THAT WILL MOVE ACROSS NEW
ENGLAND SUNDAY NIGHT WITH A WEAK SURFACE LOW TRACKING THROUGH
SOUTHERN QUEBEC. A FEW MORE LIGHT SNOW SHOWERS WILL BE POSSIBLE
MAINLY IN THE MOUNTAINS. SEASONABLY COLD AIR WILL MOVE IN FOR
MONDAY.
THE FAST FLOW ALOFT CONTINUES THROUGH THE WEEK WITH WAVE AFTER
WAVE CROSSING THROUGH THE FLOW. ANOTHER WAVE APPROACHES ON TUESDAY
WITH A WARM FRONT LIFTING NORTHWARD INTO CENTRAL PARTS OF NEW
HAMPSHIRE AND MAINE BY TUESDAY NIGHT INTO WEDNESDAY. THIS MAY LEAD
TO SOME LIGHT SNOW BUT OVERALL FORCING LOOKS WEAK UNTIL WEDNESDAY
WHEN SURFACE LOW PRESSURE TRACKS EASTWARD ALONG THE WARM FRONT.
BEST PRECIPITATION CHANCES WILL BE FURTHER TO THE NORTH. WARM AIR
IN PLACE SOUTH OF THE WARM FRONT WILL YIELD MOSTLY RAIN AS
PRECIPITATION TYPE... WHILE NORTH OF THE FRONT SNOW IS MORE
LIKELY.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
MAINLY LIFR CONDITIONS...IMPROVING TO VFR THIS EVENING WITH THE
PASSAGE OF THE SURFACE LOW AND A WIND SWITCH TO THE WEST.
LONG TERM...
MOSTLY VFR CONDITIONS EXPECTED. MOST LIKELY TIMES FOR
FLIGHT RESTRICTIONS WILL BE SUNDAY NIGHT AND AGAIN TUESDAY THROUGH
WEDNESDAY.
&&
.MARINE...
SHORT TERM...
HAVE ISSUED A GALE WARNING FOR THE OUTER WATERS THROUGH TONIGHT AS
SURFACE LOW INTENSIFIES...PULLS TO OUR EAST...AND INCREASES THE
GRADIENT AS WELL AS THE COLD AIR ADVECTION.
LONG TERM...
MAY SEE WINDS REACH 30 OR 35 KT BEHIND A COLD FRONT ON
SATURDAY NIGHT. ANOTHER FAST MOVING FRONT WILL CROSS THE WATERS
SUNDAY NIGHT WITH GUSTY WINDS BEHIND IT AS WELL.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ019>022.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ012>014.
NH...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NHZ005-006.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR ANZ151-153.
GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ150-152-154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
512 AM EST FRI JAN 27 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST PROMPTING A SECONDARY COASTAL
LOW TO DEEPEN ALONG THE NEW ENGLAND COAST THIS AFTERNOON. THE LOW
WILL EXIT INTO THE CANADIAN MARITIMES TONIGHT. ANOTHER LOW WILL
TRACK THROUGH SOUTHERN CANADA ON SATURDAY NIGHT WITH A WEAK COLD
FRONT CROSSING NORTHERN NEW ENGLAND. ANOTHER FRONT WILL CROSS NEW
ENGLAND SUNDAY NIGHT WITH COLDER TEMPERATURES BEHIND IT. A WARM
FRONT WILL LIFT NORTHWARD INTO NORTHERN NEW ENGLAND TUESDAY NIGHT
AND LOW PRESSURE WILL TRACK ALONG THE WARM FRONT ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...
HAVE UPDATED THE FORECASTS AND GRIDS TO ACCOUNT FOR CURRENT
CONDITIONS WITH THE ANTICIPATED CHANGEOVER IN FULL SWING ACROSS
SOUTHERN ZONES. HAVE REMOVED THE COAST FROM THE WINTER WEATHER
ADVISORIES AS TEMPERATURES HAVE CLIMBED TO AT OR ABOVE FREEZING IN
MOST LOCATIONS AS THE ONSHORE EASTERLIES CONTINUE OFF THE BRINK.
OVER SOUTHERN NEW HAMPSHIRE AND INTERIOR SOUTHWEST
MAINE...WARM AIR HAS SUFFICIENTLY ENTERED THE REGION...BOTH AT THE
SURFACE AND ALOFT TO CHANGE THE PTYPE TO RAIN.
LATEST SURFACE ANALYSIS CONTINUES TO SHOW THE BEST PRESSURE FALLS
ALONG THE MASSACHUSETTS COASTLINE WHILE LOW PRESSURE LINGERS BACK
IN WRN PA. WINDS HAVE BACKED OVER THE LAST HOUR ALONG THE COAST.
THIS TREND WILL BE MONITORED VERY CLOSELY IN THE EVENT THE
SECONDARY LOW DEVELOPS FURTHER SOUTH NEAR MASSACHUSETTS...INSTEAD
OF THE MAINE COASTLINE. THIS WOULD HAVE RAMIFICATIONS TO THE LOW
LEVEL THERMAL PROFILE AND PTYPES FOR TODAY...BRINGING A SLIGHTLY COLDER
SOLUTION TO THIS EVENT OVER CENTRAL AND NORTHERN AREAS.
PREV DISC...
00Z SOUNDING AT GYX REMAINS VERY DRY IN THE LOWER LEVELS.
THIS COOL/DRY AIR IS ENTRENCHED MORE THAN EVEN THE COLDEST GFS
SCENARIO HAS TO OFFER. THIS HAS KEPT PCPN IN THE FORM OF SNOW FOR
A LONGER PERIOD ACROSS SOUTHERN MAINE AND NEW HAMPSHIRE.
LATEST HRRR RUN PUSHES THE PCPN TO QUICKLY AND AGRESSIVELY INTO
THIS DRY AIR. HOWEVER...ATMOSPHERE WILL SATURDAY OVER THE NEXT
HOUR OR TWO OVER NORTHERN PORTIONS OF THE FORECAST AREA.
MAIN BAND OF STEADY PCPN WILL CONTINUE TO MOVE NORTHWARD OUT OF
SOUTHERN NEW HAMPSHIRE OVER THE NEXT FEW HOURS. PTYPE WILL
TRANSITION FROM ALL SNOW TO SLEET AND FREEZING RAIN OVER
SOUTHERNMOST NH AND FAR SOUTHWEST MAINE OVER THE NEXT HOUR OR TWO
AS WARM AIR ARRIVES BOTH IN THE BOUNDRY LAYER AND ALOFT. PTYPE
WILL SWITCH TO RAIN RIGHT ALONG THE COAST AFTER A QUICK INCH OR
TWO HAS FALLEN.
MADE SOME MINOR ADJUSTMENTS TO THE SNOWFALL MAP FOR THE WEB TO
SMOOTH AND MODIFY SOME OF THE DATA. ALL WARNINGS AND ADVISORIES
WILL REMAIN IN PLACE THROUGH 21Z.
TIMING OF CHANGEOVER AND STEADY PCPN APPEARS TO BE ON TRACK. MADE
ONLY MINOR ADJUSTMENTS TO THE GRIDS. MAY NEED TO ADDRESS THE
MARINE FCST WITH GALES SHORTLY.
FAVORED COOLER MAV TEMPS FOR TODAYS MAXES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
AFTER SOME PCPN OVER EASTERN AREAS EARLY...CLEARING IS EXPECTED
THIS EVENING AS THE SURFACE LOW PROGRESSES INTO THE CANADIAN
MARITIMES. THIS WILL BE FOLLOWED BY A WEAK RIDGE OF HIGH PRESSURE
LATE TONIGHT. HOWEVER...SOME HIGH...THIN CLOUDINESS WILL ALREADY
BE INVADING THE SKY BY MIDDAY SATURDAY AS A WEAK TROUGH OF LOW
PRESSURE QUICKLY APPROACHES NORTHERN NEW ENGLAND. WITH DRY
ATMOSPHERE IN PLACE IN THE LOWER LEVELS...WE EXPECT ANY PCPN TO
HOLD OFF UNTIL AFTER DARK.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
OVER THE OUTLOOK PERIOD FAST MOVING CLIPPERS WITH VERY LIMITED
MOISTURE WILL BE MOVING THROUGH A RATHER ZONAL WESTERLY FLOW ALLOWING
EXCHANGES IN AIR MASSES ABOUT EVERY 48 HRS. TEMPS WILL GENERALLY
BE AVERAGING ABOVE NORMAL THROUGH MOST OF THE PERIOD.
WITH THAT GENERAL OUTLLOK IN MIND..MORE SPECIFICALLY...A RIDGE OF
HIGH PRESSURE CROSSES THE AREA ON SATURDAY WITH WARMER
TEMPERATURES AND DRY CONDITIONS.
A FAST MOVING CLIPPER MOVES EAST THROUGH ONTARIO AND INTO QUEBEC
LATE SATURDAY INTO SATURDAY NIGHT... SPREADING SCATTERED SNOW
SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND WESTERN MAINE.
A COLD FRONT WILL PUSH THROUGH AS WELL WITH COLDER TEMPERATURES
AND GUSTY WEST WINDS BEHIND IT.
A WEAK RIDGE OF PRES SETTLES OVER THE AREA SUNDAY BUT QUICKLY
FOLLOWED BY ANOTHER FAST MOVING CLIPPER THAT WILL MOVE ACROSS NEW
ENGLAND SUNDAY NIGHT WITH A WEAK SURFACE LOW TRACKING THROUGH
SOUTHERN QUEBEC. A FEW MORE LIGHT SNOW SHOWERS WILL BE POSSIBLE
MAINLY IN THE MOUNTAINS. SEASONABLY COLD AIR WILL MOVE IN FOR
MONDAY.
THE FAST FLOW ALOFT CONTINUES THROUGH THE WEEK WITH WAVE AFTER
WAVE CROSSING THROUGH THE FLOW. ANOTHER WAVE APPROACHES ON TUESDAY
WITH A WARM FRONT LIFTING NORTHWARD INTO CENTRAL PARTS OF NEW
HAMPSHIRE AND MAINE BY TUESDAY NIGHT INTO WEDNESDAY. THIS MAY LEAD
TO SOME LIGHT SNOW BUT OVERALL FORCING LOOKS WEAK UNTIL WEDNESDAY
WHEN SURFACE LOW PRESSURE TRACKS EASTWARD ALONG THE WARM FRONT.
BEST PRECIPITATION CHANCES WILL BE FURTHER TO THE NORTH. WARM AIR
IN PLACE SOUTH OF THE WARM FRONT WILL YIELD MOSTLY RAIN AS
PRECIPITATION TYPE... WHILE NORTH OF THE FRONT SNOW IS MORE
LIKELY.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
MAINLY LIFR CONDITIONS...IMPROVING TO VFR THIS EVENING WITH THE
PASSAGE OF THE SURFACE LOW AND A WIND SWITCH TO THE WEST.
LONG TERM...
MOSTLY VFR CONDITIONS EXPECTED. MOST LIKELY TIMES FOR
FLIGHT RESTRICTIONS WILL BE SUNDAY NIGHT AND AGAIN TUESDAY THROUGH
WEDNESDAY.
&&
.MARINE...
SHORT TERM...
HAVE ISSUED A GALE WARNING FOR THE OUTER WATERS THROUGH TONIGHT AS
SURFACE LOW INTENSIFIES...PULLS TO OUR EAST...AND INCREASES THE
GRADIENT AS WELL AS THE COLD AIR ADVECTION.
LONG TERM...
MAY SEE WINDS REACH 30 OR 35 KT BEHIND A COLD FRONT ON
SATURDAY NIGHT. ANOTHER FAST MOVING FRONT WILL CROSS THE WATERS
SUNDAY NIGHT WITH GUSTY WINDS BEHIND IT AS WELL.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ019>022.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ012>014.
NH...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NHZ005-006.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR ANZ151-153.
GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ150-152-154.
&&
$$
JC/RAM
AREA FORECAST DISCUSSION
NWS DULUTH MN
934 AM CST FRI JAN 27 2012
.UPDATE...CURRENT RADAR TRENDS MATCH UP WELL WITH THE 11Z HRRR AND
HAVE ADJUSTED THE GRIDS THIS AFTERNOON TO LEAN TOWARDS ITS
SOLUTION. NO CHANGE FOR THE REST OF THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 546 AM CST FRI JAN 27 2012/
AVIATION...12Z TAF ISSUANCE...
A WEATHER SYSTEM WILL MOVE FROM EASTERN ND TO CENTRAL MN THIS
MORNING. EXPECT A PERIOD OF ABOUT 3 TO 5 HOURS OF IFR/MVFR CIGS AT
ALL TAF SITES...BEGINNING AT KBRD/KINL THIS MORNING...AND THEN AT
KHIB/KDLH/KHYR THIS AFTERNOON AS THE SYSTEM PASSES THROUGH
MN. THE PERIOD OF IFR/MVFR CIGS WILL BE ACCOMPANIED BY -SN AND
REDUCED VSBY. KINL SHOULD ESCAPE MOST OF THE SNOW...BUT
KBRD/KHIB/KDLH/KHYR WILL CLOSER TO THE FOCUS OF THE SNOWFALL AND
WILL SEE A PERIOD OF LOW END MVFR VSBYS. THIS WINDS TODAY WILL
GENERALLY BE LIGHT FROM THE WEST TO NORTHWEST...WITH SOME
INCREASING WESTERLY WINDS EARLY THIS EVENING. ONCE THE LOW MVFR
CIGS PASS...EACH TAF SITE SHOULD SEE HIGH BASED CIGS THROUGH
THE REST OF THE AFTERNOON AND INTO TONIGHT. WIND SHEAR MAY BE AN
ISSUE AT KBRD THIS EVENING DUE TO STRONG NORTHWEST WINDS
ALOFT...BUT OTHERWISE WIND SHEAR IS NOT EXPECTED TO BE AN ISSUE
FOR THE OTHER TAF SITES.
PREV DISCUSSION... /ISSUED 306 AM CST FRI JAN 27 2012/
SHORT TERM...THROUGH SATURDAY.
WE MADE SIGNIFICANT CHANGES TO THE FORECAST TODAY...NAMELY
SPREADING MUCH HIGHER POPS NORTH TO NEARLY THE INTERNATIONAL
BORDER.
SURFACE LOW PRESSURE OVER NORTH CENTRAL NORTH DAKOTA WILL MOVE ESE
TODAY...WITH 08Z SURFACE ANALYSIS SHOWING 2.5MB PRESSURE FALLS
JUST TO THE ESE OF THE LOW CENTER. THE GFS CONTINUES TO BE THE
FURTHEST SOUTH WITH THE TRACK OF THIS CLIPPER...AND THE RESULTANT
SNOW. THE 00Z ECMWF HAS SHIFTED THE LOW/PRECIP FURTHER NORTH...THE
NAM CONTINUES TO BE NORTH...AND THE HIGHER RESOLUTION 4KM WRF/3KM
HRRR SUGGEST SNOW WILL FALL FURTHER NORTH AS WELL. NAM ALSO SHOWS A
NICE FGEN SIGNATURE THAT MOVES THROUGH CASS/ITASCA COUNTIES...ESE
INTO WI. THERE WILL BE A NICE BURST OF SNOW THAT FALLS...AND 2 TO
3 INCHES IS EXPECTED IN THE MAIN AREA OF SNOW...WITH 1 TO 2 INCHES
NORTH AND SOUTH...AND EVEN LESS ALONG THE INTERNATIONAL BORDER. A
FEW HIGHER AMOUNTS WILL BE POSSIBLE AS WELL TO 4 INCHES. THE EXACT
LOCATION OF THE HEAVIER SNOW BAND AND THE SPEED OF THE SYSTEM
PRECLUDES US FROM ISSUING AN ADVISORY AT THIS TIME...BUT WE WILL
MONITOR RADAR OVER THE NEXT FEW HOURS AND ISSUE IF CONFIDENCE
INCREASES. AT THIS TIME...WE HAVE THE HIGHEST SNOW TOTALS ACROSS
NORTHERN CASS/SOUTHERN ITASCA COUNTIES INTO THE TWIN PORTS AND
ACROSS NORTHERN WISCONSIN.
SNOW SHOULD START THIS MORNING OVER OUR WESTERN CWA...REACH
THE EASTERN IRON RANGE...TWIN PORTS...INTERSTATE 35 CORRIDOR BY
EARLY AFTERNOON...THEN OUR EASTERN WISCONSIN ZONES BY MID-LATE
AFTERNOON.
THE SNOW WILL END IN OUR WEST THIS AFTERNOON...AND LINGER THROUGH
THE EVENING OVER PORTIONS OF NORTHWEST WISCONSIN.
COLDER AIR MOVES IN BEHIND THE LOW TONIGHT INTO SATURDAY. LOW
LEVEL FLOW IS TOO WESTERLY TO GET ANY SIGNIFICANT LES.
CYCLONIC UPPER LEVEL FLOW AND COLDER AIR MAY LEAD TO SOME LIGHT
SNOW SHOWERS ON SATURDAY OVER PORTIONS OF THE NORTHLAND. A
STRONGER SHORTWAVE WILL DIVE JUST SOUTHWEST OF THE CWA AND KEEP
THE HIGHER CHANCES FOR SNOW OUT OF OUR CWA. HIGHS SATURDAY WILL
RANGE FROM THE UPPER TEENS IN THE ARROWHEAD...TO THE TWENTIES
ELSEWHERE.
LONG TERM...SATURDAY NIGHT - THURSDAY...
SATURDAY NIGHT...THE NORTHLAND WILL BEGIN THE PERIOD IN COLD
NORTHWEST FLOW WITH A PASSING SHORTWAVE AND TROUGH. THERE COULD BE
LIGHT SNOW ACROSS THE SOUTHERN FA RELATED TO THE PASSING
SHORTWAVE...AND LAKE EFFECT SNOW SHOWERS ALONG PARTS OF THE SOUTH
SHORE DUE TO THE COLD NORTHWEST FLOW OVER THE LAKE. THE LATEST
MAV/MET/MEX GUIDANCE WAS INDICATING MUCH OVERNIGHT LOW
TEMPERATURES...SO LOWERED THE FORECAST.
SUNDAY...A RIDGE OF HIGH PRESSURE WILL MOVE INTO THE NORTHLAND
WHICH WILL RELAX THE NORTHWEST WINDS AND CAUSE CLEARING SKIES FROM
WEST TO EAST. THERE COULD BE LINGERING LAKE EFFECT SNOW SHOWERS
ALONG PARTS OF THE SOUTH SHORE...MOSTLY IN THE MORNING BEFORE THE
NORTHWESTERLY WINDS BECOME WESTERLY BY THE AFTERNOON.
SUNDAY NIGHT AND MONDAY...IT LOOKS LIKE A NORTHWEST TO SOUTHEAST
ORIENTATED WARM FRONT WILL MOVE INTO THE WESTERN FA OVERNIGHT AND
THE EASTERN FA MONDAY. THE FRONT COULD BRING LIGHT PCPN TO THE
FA...BUT THE MODELS DISAGREE ON THE TIMING/LOCATION/STRENGTH. BASED
ON SOUNDINGS...IT WOULD APPEAR THE PCPN WOULD INITIALLY FALL AS
LIGHT SNOW...BUT DRYING IN THE MID LEVELS BEHIND THE FRONT COULD
RESULT IN A MIXTURE OF LIGHT SNOW AND FREEZING DRIZZLE/RAIN ON
MONDAY.
MONDAY NIGHT THROUGH THURSDAY...THE MODELS SHOW A WEAK LOW PRESSURE
SYSTEM MOVING THROUGH THE UPPER MIDWEST WHICH COULD BRING LIGHT PCPN
TO THE NORTHLAND SOMETIME MONDAY NIGHT THROUGH TUESDAY NIGHT. BASED
ON SURFACE TEMPERATURES AND SOUNDINGS...IT WOULD APPEAR THERE COULD
BE A MIXTURE OF RAIN AND SNOW ACROSS THE FAR SOUTHERN FA TUESDAY. IT
THEN APPEARS WEAK HIGH PRESSURE WILL KEEP THE NORTHLAND DRY THROUGH
THE REMAINDER OF THE FORECAST.
&&
.POINT TEMPS/POPS...
DLH 30 16 22 2 / 80 10 10 10
INL 28 12 19 -6 / 40 10 30 20
BRD 30 16 24 2 / 80 10 20 20
HYR 32 14 23 2 / 80 50 10 10
ASX 33 17 24 6 / 80 50 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
600 AM CST FRI JAN 27 2012
.AVIATION... /12Z TAF ISSUANCE/
LOW PRESSURE OVER EASTERN ND...WITH A COLD FRONT TRAILING SOUTH...
WILL REACH THE TWIN CITIES AROUND 21Z AND KEAU BY 02Z. CONFIDENCE
ON THE SNOW FORECAST TODAY IS LOW. THIS IS DUE TO THE SYSTEM
BASICALLY BEING IN TWO PARTS...ONE TO OUR NORTH AND THE OTHER TO
OUR SOUTH. REFLECTIVITY TRENDS IN THE VARIOUS WRF MODELS
OVERNIGHT ARE SUGGESTING MORE BANDING TO THE SNOW TODAY. THIS
WOULD MEAN MORE FLUCTUATIONS IN THE CEILING/VISIBILITY RATHER THAN
STEADY LOW CONDITIONS. TIMING REMAINS CONSISTENT WITH THE PREVIOUS
TAF PACKAGE WITH ADJUSTMENTS OF AN HOUR OR SO MADE. THE SNOW
TODAY WILL ONLY LAST FOR A COUPLE OF HOURS. RATHER STRONG
NORTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE LOW...ESPECIALLY
AT KRWF AND KAXN. SPEEDS SUSTAINED IN THE 20 TO 25 KNOT RANGE
LIKELY ALONG WITH GUSTS APPROACHING 35 KNOTS. BRISK NORTHWEST
WINDS TO CONTINUE TONIGHT. THERE ARE SOME INDICATIONS THAT AN AREA
OF MVFR CEILINGS WILL SPREAD SOUTHEAST ACROSS EASTERN MN AND
WESTERN WI LATE TONIGHT AND SATURDAY AND THIS WAS INCLUDED IN
KMSP...KRNH AND KEAU AFTER 09Z.
KMSP...SOME LIGHT SNOW MAY REACH THE AIRFIELD BETWEEN 16Z AND
18Z...BUT THE MAIN SNOW REMAINS IN THE 18Z-21Z TIME FRAME WITH
VISIBILITY NEAR 1SM ALONG WITH CEILINGS DOWN TO VV008. THE SNOW
ENDS BY LATE AFTERNOON ALONG WITH WINDS SHIFTING TO THE NORTHWEST
(290-310) NEAR 15 KNOTS WITH GUSTS TO 25 KNOTS. THE WINDS WILL
CONTINUE THROUGH THE EVENING.
&&
.DISCUSSION... /ISSUED 427 AM CST FRI JAN 27 2012/
LIGHT SNOW EVENT STILL ON COURSE FOR TODAY. SNOW IN THE DAKOTAS
IS ONGOING WITH MOST OF THE AIRPORTS UNDERNEATH THE SNOW SHOWING
BETWEEN 1-2SM VISIBILITY. THE 27.00/06Z NAM/GFS AND 27.00Z EC NOT
DEVIATING TOO FAR FROM THURSDAY`S MODEL GUIDANCE. OVER THE PAST
24-30HR...THE MODEL SOLUTIONS HAVE SHIFTED THE BEST AXIS OF QPF
NORTH WITH TIME. LIKELY A FEW MORE LOCATIONS SEEING 2-4 INCHES
ACROSS NORTHERN PORTIONS OF MINNESOTA...ESPECIALLY GIVEN THE MORE
FAVORABLE PROFILE FOR DENDRITE SNOW GROWTH. THE MODEL GUIDANCE AND
EVEN THE RADAR THIS MORNING SHOWING TWO SEPARATE AREAS OF ENHANCED
SNOW...WITH A RELATIVE WEAKNESS OVER EASTERN SD. THESE TWO AREAS
LINE UP PRETTY WELL WITH THE 700-400MB DIFFERENTIAL VORTICITY
ADVECTION...AND SEEMS TO BE BETTER 850MB TEMPERATURE ADVECTION OFF
THE RUC IN THE VICINITY OF THESE TWO AREAS AS WELL. LOWEST SNOW
TOTALS WILL LIKELY BE IN WEST CENTRAL MN WHERE THE PRECIP SHOULD
LARGELY SPLIT THE AREA AND IT MIGHT ONLY MANAGE A TRACE OF SNOW.
THE TWO AREAS SHOULD FILL IN BY THE TIME THE WAVE MAKES IT INTO
EASTERN MN AND WESTERN WI EARLY THIS AFTERNOON...SO MOST LOCATIONS
WILL AT LEAST SEE A FEW TENTHS OF SNOW. TRIED TO TIME THE POP/WX
FORECAST WITH HOURLY GRIDS THIS MORNING AND WALK A BAND OF 60-90%
POPS ACROSS THE FORECAST AREA LATE THIS MORNING AND AFTERNOON.
PROBABLY COULD BE DONE A LITTLE MORE 80-100% POPS...BUT THE SNOW
WILL BE PRETTY LIGHT. BASED THE HOURLY TREND ON A LOT OF VARIOUS
WRF-NMM AND WRF-ARW SIMULATIONS FROM NCEP/SPC/MPX. MUCH BETTER
ISENTROPIC ADIABATIC OMEGA SLIDING ACROSS THE GRAND FORKS AND
DULUTH FORECAST AREAS. BEST CHANCE FOR 1-2" WILL BE ACROSS
PORTIONS OF CENTRAL MINNESOTA...LIKELY NEAR AND NORTH OF A LINE
FROM FERGUS FALLS...TO LITTLE FALLS...TO RICE LAKE IN WI. SNOW
LARGELY MOVES OUT OF THE FORECAST THIS EVENING.
BEYOND TODAY...THERE ARE A COUPLE OTHER MINOR SNOW EVENTS IN THE
WORKS SATURDAY THROUGH WEDNESDAY. NICE 500MB SHORT WAVE DROPS
SOUTH OUT OF SASKATCHEWAN ON SATURDAY WITH SOME SURFACE RESPONSE
AND A WEAK SURFACE TROUGH. CONVERGENCE ISN`T OVERLY STRONG...BUT
PROBABLY WORTH CHANCE POPS FOR SATURDAY AFTERNOON AND EVENING.
OVERALL THE WEEKEND WILL BE COOLER AFTER TODAY`S SYSTEM...BUT LIKE
SO MANY TIMES THIS WINTER...COLD FRONTS CAN ONLY MANAGE TO COOL AS
DOWN TO NEAR NORMAL. WARM FRONT COMES THROUGH SUNDAY NIGHT...SO
ONCE AGAIN HAVE SMALL POPS IN THE FORECAST DURING THIS TIME FRAME
DUE TO THE ISENTROPIC LIFT. EC IS A LITTLE STRONGER WITH THE UPPER
TROUGH AND SURFACE LOW ON TUESDAY COMPARED TO THE GFS...BUT IT`S
ALSO FARTHER TO THE NORTH. THE SECOND HALF OF NEXT WEEK IS QUITE
WARM IF YOU TRUST THE GFS AND THE PRONOUNCED LONG WAVE RIDGING.
THE EC HOLD THE RIDGE BACK TO THE WEST.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
427 AM CST FRI JAN 27 2012
.DISCUSSION...
LIGHT SNOW EVENT STILL ON COURSE FOR TODAY. SNOW IN THE DAKOTAS IS
ONGOING WITH MOST OF THE AIRPORTS UNDERNEATH THE SNOW SHOWING
BETWEEN 1-2SM VISIBILITY. THE 27.00/06Z NAM/GFS AND 27.00Z EC NOT
DEVIATING TOO FAR FROM THURSDAY`S MODEL GUIDANCE. OVER THE PAST
24-30HR...THE MODEL SOLUTIONS HAVE SHIFTED THE BEST AXIS OF QPF
NORTH WITH TIME. LIKELY A FEW MORE LOCATIONS SEEING 2-4 INCHES
ACROSS NORTHERN PORTIONS OF MINNESOTA...ESPECIALLY GIVEN THE MORE
FAVORABLE PROFILE FOR DENDRITE SNOW GROWTH. THE MODEL GUIDANCE AND
EVEN THE RADAR THIS MORNING SHOWING TWO SEPARATE AREAS OF ENHANCED
SNOW...WITH A RELATIVE WEAKNESS OVER EASTERN SD. THESE TWO AREAS
LINE UP PRETTY WELL WITH THE 700-400MB DIFFERENTIAL VORTICITY
ADVECTION...AND SEEMS TO BE BETTER 850MB TEMPERATURE ADVECTION OFF
THE RUC IN THE VICINITY OF THESE TWO AREAS AS WELL. LOWEST SNOW
TOTALS WILL LIKELY BE IN WEST CENTRAL MN WHERE THE PRECIP SHOULD
LARGELY SPLIT THE AREA AND IT MIGHT ONLY MANAGE A TRACE OF SNOW.
THE TWO AREAS SHOULD FILL IN BY THE TIME THE WAVE MAKES IT INTO
EASTERN MN AND WESTERN WI EARLY THIS AFTERNOON...SO MOST LOCATIONS
WILL AT LEAST SEE A FEW TENTHS OF SNOW. TRIED TO TIME THE POP/WX
FORECAST WITH HOURLY GRIDS THIS MORNING AND WALK A BAND OF 60-90%
POPS ACROSS THE FORECAST AREA LATE THIS MORNING AND AFTERNOON.
PROBABLY COULD BE DONE A LITTLE MORE 80-100% POPS...BUT THE SNOW
WILL BE PRETTY LIGHT. BASED THE HOURLY TREND ON A LOT OF VARIOUS
WRF-NMM AND WRF-ARW SIMULATIONS FROM NCEP/SPC/MPX. MUCH BETTER
ISENTROPIC ADIABATIC OMEGA SLIDING ACROSS THE GRAND FORKS AND
DULUTH FORECAST AREAS. BEST CHANCE FOR 1-2" WILL BE ACROSS
PORTIONS OF CENTRAL MINNESOTA...LIKELY NEAR AND NORTH OF A LINE
FROM FERGUS FALLS...TO LITTLE FALLS...TO RICE LAKE IN WI. SNOW
LARGELY MOVES OUT OF THE FORECAST THIS EVENING.
BEYOND TODAY...THERE ARE A COUPLE OTHER MINOR SNOW EVENTS IN THE
WORKS SATURDAY THROUGH WEDNESDAY. NICE 500MB SHORT WAVE DROPS
SOUTH OUT OF SASKATCHEWAN ON SATURDAY WITH SOME SURFACE RESPONSE
AND A WEAK SURFACE TROUGH. CONVERGENCE ISN`T OVERLY STRONG...BUT
PROBABLY WORTH CHANCE POPS FOR SATURDAY AFTERNOON AND EVENING.
OVERALL THE WEEKEND WILL BE COOLER AFTER TODAY`S SYSTEM...BUT LIKE
SO MANY TIMES THIS WINTER...COLD FRONTS CAN ONLY MANAGE TO COOL AS
DOWN TO NEAR NORMAL. WARM FRONT COMES THROUGH SUNDAY NIGHT...SO
ONCE AGAIN HAVE SMALL POPS IN THE FORECAST DURING THIS TIME FRAME
DUE TO THE ISENTROPIC LIFT. EC IS A LITTLE STRONGER WITH THE UPPER
TROUGH AND SURFACE LOW ON TUESDAY COMPARED TO THE GFS...BUT IT`S
ALSO FARTHER TO THE NORTH. THE SECOND HALF OF NEXT WEEK IS QUITE
WARM IF YOU TRUST THE GFS AND THE PRONOUNCED LONG WAVE RIDGING.
THE EC HOLD THE RIDGE BACK TO THE WEST.
&&
.AVIATION.../06Z TAF ISSUANCE/
STILL A LOW RISK OF MVFR VSBYS IN FOG WEST CENTRAL WI FOR A SHORT
PERIOD OVERNIGHT UNTIL VFR CLOUDS MOVE INT, OTHERWISE LOW
PRESSURE CENTER AND TROUGH ON TARGET TO MOVE ACROSS THE AREA ON
FRIDAY...WITH LOW PRESSURE CENTER TRACKING ACROSS CENTRAL MN
DURING MID DAY. STILL LOOKS LIKE A 2-4 HOUR PERIOD OF SNOW WITH
THE LONGER DURATION OVER EASTERN SECTIONS OF THE FORECAST AREA.
THE GREATER RISK OF IFR VSBYS APPEARS TO BE ACROSS CENTRAL MN INTO
WEST CENTRAL WI AND POSSIBLY THE KMSP AREA. HAVE ADJUSTED THE
BEGINNING TIME A BIT LATER EASTERN AREAS. CIGS SHOULD PRIMARILY BE
MVFR IN THE SNOW BUT AREAS OF 1SM COULD YIELD IFR CIGS AS WELL.
THE LOWER CONDITIONS VCNTY KRWF NOT LIKELY TO LAST MUCH LONGER
THAN 2 HOURS. ACCUMULATIONS MOST AREAS COULD REACH AN INCH BUT UP
TO 2 INCHES CENTRAL AND EASTERN AREAS. A 2 HOUR PERIOD OF MVFR
CIGS COULD PERSIST BEHIND THE WAVE AND THEN SCT ON THE LOW CLOUDS
WEST LATER AFTERNOON AND THEN EASTERN MN FRIDAY EVENING.
THE OTHER ISSUE IS GUSTY NORTHWEST WINDS BEHIND THE TROUGH
ESPECIALLY OVER WEST CENTRAL MN. WILL INCLUDE THE HIGHER GUSTS NEAR
KRWF UP TO 30 KNOTS AND 20 TO 25 KNOTS OVER THE REST OF MN.
KMSP...VFR UNTIL SNOW MOVES IN 15Z-16Z WITH STILL A RISK OF IFR
VSBYS FOR 3 TO 4 HOURS AND DOWN TO 1SM AND CIGS 008. LOW END MVFR
BELOW 017 DOMINANT THOUGH. TIMING ABOUT AS PREV FORECAST BUT
PERHAPS A BIT LATER START. SNOW ACCUMULATION AROUND 1 INCH. HAVE
ADDED SOME CLEARING BEHIND THE WAVE FRIDAY EVENING. NORTHWEST
WINDS WITH GUSTS OF 22 KNOTS POSSIBLE BEHIND THE SYSTEM LATE
FRIDAY AFTERNOON AND CONTINUING INTO EVENING.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/JPR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
752 AM CST FRI JAN 27 2012
AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
BULK OF THE PRECIPITATION HAS MOVED TO THE NORTH OF THE TAF SITES
AND MAY SEE A BRIEF PERIOD OF A MIX OR SPRINKLES THROUGH 16Z AS
THE LIFT CONTINUES TO EXIT EASTERN NEBRASKA. CIGS SHOULD BE MAINLY
VFR. FOCUS THEN TURNS TO THE WINDS WHICH WILL INCREASE FROM THE
AT 18-25KT WITH GUSTS 25 TO 35KT AFTER 17Z. THE STRONG WINDS WILL
LAST INTO THE EARLY EVENING THEN DECREASE TO UNDER 12KTS AFTER
03Z.
&&
.PREV DISCUSSION... /ISSUED 417 AM CST FRI JAN 27 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE HAS BEEN ON PRECIPITATION
AMOUNTS/TYPE...MAINLY THIS MORNING...BUT APPARENTLY WITH MINOR
ACCUMULATIONS. AFTER THAT...WINDS THIS AFTERNOON AND THEN
TEMPERATURES ON MONDAY MAIN HAVE BEEN MAIN FOCUS.
MODEST SHORT WAVE ENERGY DROPPING SE TOWARD NORTHERN NEBRASKA THIS
MORNING WILL PROVIDE A SHOT OF STRONG LIFT TO FORECAST
AREA...ESPECIALLY NORTHERN ZONES. IT APPEARS LIFT WAS MOSTLY FROM
WARM ADVECTION EARLY AS ISENTROPIC UPGLIDE WAS STRONG IN 290-295
K LAYER. 06Z NAM LINGERED THIS LIFT LONGER INTO THIS AFTERNOON
COMPARED TO 00Z GFS...BUT NAM WAS MORE PROGRESSIVE WITH QPF FIELDS
COMPARED TO ITS 06Z RUC COUNTERPART. ALSO BASED ON TELCO/SURFACE
REPORTS THROUGH 09Z...QPF AMOUNTS FROM 06Z NAM APPEARED WAY TOO
HIGH. SO THAT MODEL APPEARED A LITTLE SUSPECT AND THUS LEANED
CLOSER TO GFS. SINCE MEASURABLE PRECIPITATION THROUGH 09Z HAD BEEN
HARD TO COME BY...LOWERED/DROPPED PRECIP MENTION EARLY THIS
MORNING SOUTHERN ZONES WITH SPRINKLES MENTIONED IN 15Z-18Z PD
AS SURFACE TEMPERATURES CLIMB ABOVE FREEZING. WILL COUNT ON LIFT
BEING STRONG ENOUGH TO COOL WARM LAYER ALOFT DOWN NORTHERN ZONES
SO THAT MAIN PRECIP TYPE EARLY WILL BE SNOW TRANSITIONING TO
SPRINKLES/FLURRIES AS BOUNDARY LAYER TEMPERATURES WARM WITH MIXING
LATER THIS MORNING. THAT LEFT A SMALL TRANSITION AREA ALONG PLATTE
RIVER WHERE NAM/GFS SUGGESTED A PERIOD OF FREEZING RAIN
POSSIBLE...ALTHOUGH THAT WILL BE CHANGED TO FREEZING SPRINKLES IN
LEGACY ZFP PRODUCT. TO FURTHER COMPLICATED MATTERS... LATEST RUC
SOUNDINGS KEPT ALL BUT FAR NW ZONES DRY INTO THIS AFTERNOON. AFTER
TROUGH PASSES...INCREASING NORTHWEST SURFACE WINDS COULD APPROACH
WIND ADVISORY CRITERIA W THROUGH NRN ZONES...BUT SPATIAL COVERAGE
AND LENGTH OF TIME WAS TOO UNCERTAIN TO ISSUE WIND ADVISORY WITH
THIS PACKAGE.
MADE LITTLE CHANGES TO TONIGHT THROUGH SUNDAY PERIOD. DECENT
MIXING AND WEAK WARM ADVECTION ON SATURDAY COULD PROVIDE A LITTLE
WARMER TEMPERATURES COMPARED TO TODAY. THEN SECONDARY PUSH OF
COLDER AIR SATURDAY NIGHT/EARLY SUNDAY FOLLOWED BY POSSIBLY MORE
CLOUDS/LESS MIXING LATER IN THE DAY COULD BRING A LITTLE COOLER
READINGS TO MOST AREAS ON SUNDAY. MAIN CHANGE IN TEMPERATURE
FORECAST WAS MADE TO THE MONDAY PERIOD WHERE HIGHS WERE RAISED BY
A CATEGORY OR SO. THERE WAS DECENT AGREEMENT BETWEEN 00Z GFS/ECMWF
IN WARMER H85 AIR ALREADY OVERSPREADING AREA BY 12Z MONDAY WITH
SUNSHINE...SW WINDS AND EVEN A BIT MORE WARM ADVECTION IN THE
AFTERNOON. PAST EVENTS SIMILAR TO THIS HAS PROVIDED 50S OVER SNOW
FREE AREAS. WITH DECENT CONSISTENCY IN MODEL RUNS...HIGHS OUTSIDE
OF EXPECTED SOME SNOW COVERED NORTHERN ZONES WERE RAISED INTO
50S...HIGHEST FAR S AND WEST CENTRAL.
AFTER THAT A SERIES OF FAST MOVING AND HARD-TO-TIME SYSTEMS BUT
OVERALL ABOVE NORMAL TEMPERATURES. FINE TUNING PROBABLY BEST LEFT
TO CLOSER TO ACTUAL TIME AND NO CHANGES WERE MADE TO A BLEND OF
MODEL/PREVIOUS FORECAST.
CHERMOK
AVIATION...
06Z TAFS FOR KOFK...KLNK AND KOMA.
DETERIORATING CONDITIONS ARE EXPECTED OVERNIGHT THROUGH 18Z AS A
STORM SYSTEM BRINGS SNOW TO NORTHEAST NEBRASKA...AND A RAIN SNOW
MIX TO KLNK AND KOMA. MID LEVEL CIGS WILL LOWER TO MVFR AT KOFK BY
10Z WITH OCCASIONAL IFR TO LIFR CIGS/VSBYS IN SNOW THROUGH 16Z.
MVFR CIGS WILL BE THE RULE AFTER 10Z AT KLNK AND KOMA WITH RAIN
AND SNOW LIKELY THROUGH 18Z. BRIEF PERIODS OF IFR VSBYS/CIGS MAY
OCCUR AT KOMA THROUGH THEN. A STRONG COLD FRONT WILL BRING AN END
TO THE PRECIPITATION BY ABOUT 18Z...BUT NORTHWEST WINDS OF 20 TO
30KTS AND BROKEN MVFR CIGS WILL FOLLOW. SKIES SHOULD CLEAR AND
WINDS DIE DOWN TOWARD 15KTS BY SHORTLY AFTER 00Z.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
417 AM CST FRI JAN 27 2012
.DISCUSSION...
MAIN FORECAST CHALLENGE HAS BEEN ON PRECIPITATION
AMOUNTS/TYPE...MAINLY THIS MORNING...BUT APPARENTLY WITH MINOR
ACCUMULATIONS. AFTER THAT...WINDS THIS AFTERNOON AND THEN
TEMPERATURES ON MONDAY MAIN HAVE BEEN MAIN FOCUS.
MODEST SHORT WAVE ENERGY DROPPING SE TOWARD NORTHERN NEBRASKA THIS
MORNING WILL PROVIDE A SHOT OF STRONG LIFT TO FORECAST
AREA...ESPECIALLY NORTHERN ZONES. IT APPEARS LIFT WAS MOSTLY FROM
WARM ADVECTION EARLY AS ISENTROPIC UPGLIDE WAS STRONG IN 290-295
K LAYER. 06Z NAM LINGERED THIS LIFT LONGER INTO THIS AFTERNOON
COMPARED TO 00Z GFS...BUT NAM WAS MORE PROGRESSIVE WITH QPF FIELDS
COMPARED TO ITS 06Z RUC COUNTERPART. ALSO BASED ON TELCO/SURFACE
REPORTS THROUGH 09Z...QPF AMOUNTS FROM 06Z NAM APPEARED WAY TOO
HIGH. SO THAT MODEL APPEARED A LITTLE SUSPECT AND THUS LEANED
CLOSER TO GFS. SINCE MEASURABLE PRECIPITATION THROUGH 09Z HAD BEEN
HARD TO COME BY...LOWERED/DROPPED PRECIP MENTION EARLY THIS
MORNING SOUTHERN ZONES WITH SPRINKLES MENTIONED IN 15Z-18Z PD
AS SURFACE TEMPERATURES CLIMB ABOVE FREEZING. WILL COUNT ON LIFT
BEING STRONG ENOUGH TO COOL WARM LAYER ALOFT DOWN NORTHERN ZONES
SO THAT MAIN PRECIP TYPE EARLY WILL BE SNOW TRANSITIONING TO
SPRINKLES/FLURRIES AS BOUNDARY LAYER TEMPERATURES WARM WITH MIXING
LATER THIS MORNING. THAT LEFT A SMALL TRANSITION AREA ALONG PLATTE
RIVER WHERE NAM/GFS SUGGESTED A PERIOD OF FREEZING RAIN
POSSIBLE...ALTHOUGH THAT WILL BE CHANGED TO FREEZING SPRINKLES IN
LEGACY ZFP PRODUCT. TO FURTHER COMPLICATED MATTERS... LATEST RUC
SOUNDINGS KEPT ALL BUT FAR NW ZONES DRY INTO THIS AFTERNOON. AFTER
TROUGH PASSES...INCREASING NORTHWEST SURFACE WINDS COULD APPROACH
WIND ADVISORY CRITERIA W THROUGH NRN ZONES...BUT SPATIAL COVERAGE
AND LENGTH OF TIME WAS TOO UNCERTAIN TO ISSUE WIND ADVISORY WITH
THIS PACKAGE.
MADE LITTLE CHANGES TO TONIGHT THROUGH SUNDAY PERIOD. DECENT
MIXING AND WEAK WARM ADVECTION ON SATURDAY COULD PROVIDE A LITTLE
WARMER TEMPERATURES COMPARED TO TODAY. THEN SECONDARY PUSH OF
COLDER AIR SATURDAY NIGHT/EARLY SUNDAY FOLLOWED BY POSSIBLY MORE
CLOUDS/LESS MIXING LATER IN THE DAY COULD BRING A LITTLE COOLER
READINGS TO MOST AREAS ON SUNDAY. MAIN CHANGE IN TEMPERATURE
FORECAST WAS MADE TO THE MONDAY PERIOD WHERE HIGHS WERE RAISED BY
A CATEGORY OR SO. THERE WAS DECENT AGREEMENT BETWEEN 00Z GFS/ECMWF
IN WARMER H85 AIR ALREADY OVERSPREADING AREA BY 12Z MONDAY WITH
SUNSHINE...SW WINDS AND EVEN A BIT MORE WARM ADVECTION IN THE
AFTERNOON. PAST EVENTS SIMILAR TO THIS HAS PROVIDED 50S OVER SNOW
FREE AREAS. WITH DECENT CONSISTENCY IN MODEL RUNS...HIGHS OUTSIDE
OF EXPECTED SOME SNOW COVERED NORTHERN ZONES WERE RAISED INTO
50S...HIGHEST FAR S AND WEST CENTRAL.
AFTER THAT A SERIES OF FAST MOVING AND HARD-TO-TIME SYSTEMS BUT
OVERALL ABOVE NORMAL TEMPERATURES. FINE TUNING PROBABLY BEST LEFT
TO CLOSER TO ACTUAL TIME AND NO CHANGES WERE MADE TO A BLEND OF
MODEL/PREVIOUS FORECAST.
CHERMOK
&&
.AVIATION...
06Z TAFS FOR KOFK...KLNK AND KOMA.
DETERIORATING CONDITIONS ARE EXPECTED OVERNIGHT THROUGH 18Z AS A
STORM SYSTEM BRINGS SNOW TO NORTHEAST NEBRASKA...AND A RAIN SNOW
MIX TO KLNK AND KOMA. MID LEVEL CIGS WILL LOWER TO MVFR AT KOFK BY
10Z WITH OCCASIONAL IFR TO LIFR CIGS/VSBYS IN SNOW THROUGH 16Z.
MVFR CIGS WILL BE THE RULE AFTER 10Z AT KLNK AND KOMA WITH RAIN
AND SNOW LIKELY THROUGH 18Z. BRIEF PERIODS OF IFR VSBYS/CIGS MAY
OCCUR AT KOMA THROUGH THEN. A STRONG COLD FRONT WILL BRING AN END
TO THE PRECIPITATION BY ABOUT 18Z...BUT NORTHWEST WINDS OF 20 TO
30KTS AND BROKEN MVFR CIGS WILL FOLLOW. SKIES SHOULD CLEAR AND
WINDS DIE DOWN TOWARD 15KTS BY SHORTLY AFTER 00Z.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
917 AM EST FRI JAN 27 2012
.SYNOPSIS...
A COLD FRONT WILL TRACK ACROSS THE REGION TODAY. FAIR WEATHER
RETURNS BY TONIGHT THROUGH THE WEEKEND AS HIGH PRESSURE SETTLES OVER
THE CAROLINAS.
&&
.NEAR TERM /TODAY THROUGH SATURDAY/...
AS OF 915 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A PREFRONTAL TROUGH MOVING EAST
ACROSS CENTRAL NORTH CAROLINA...WITH A COLD FRONT MOVING INTO THE
FOOTHILLS OF NORTH CAROLINA TOWARD THE YADKIN RIVER. AMDAR SOUNDINGS
FROM 12Z TO 13Z IN VICINITY OF BOTH KGSO AND KRDU SHOWED A
CONDITIONALLY UNSTABLE AIR MASS WITH LAPSE RATES THROUGH 500MB NEAR
THE MOIST ADIABAT. DESPITE STRONG WINDS...NEAR 60KT IN PLACES...ON
THE KRAX AND TRDU RADARS...VERY MODEST INSTABILITY...VERY LOW IF ANY
DOWNDRAFT CAPE...AND THE TIME OF DAY RESULTED IN WIND GUSTS AT THEIR
HIGHEST ON OBSERVATIONS VIEWED TO THIS POINT AT OR JUST ABOVE 40
MPH. THE SPC MESOANALYSIS HAS STARTED TO SHOW INCREASING MIXED-LAYER
CAPE IN THE LOWEST 100MB TOWARD THE COAST...BUT IT APPEARS THE
THREAT OF ANY SEVERE WEATHER SHOULD NOW BE EAST OF CENTRAL NORTH
CAROLINA.
FOR THE REST OF THE DAY...THE CONDITIONALLY UNSTABLE AIR MASS WILL
CONTINUE UNTIL THE FRONT CLEARS DURING THE AFTERNOON. GIVEN THE
AVAILABLE LAPSE RATES AND MOISTURE...AND GOOD SYNOPTIC LIFT WITH THE
FRONT AND THE MID-LEVEL TROUGH...ALONG WITH A 120KT 300MB JET MOVING
EAST...EXPECT AT LEAST SCATTERED SHOWERS ASSOCIATED WITH THE FRONT.
NAM...RUC...AND HRRR WRF GUIDANCE ALL NOTE THIS...BUT SUBSIDENCE
BEHIND THE FRONT SHOULD RESULT IN RAPIDLY FALLING CHANCES FOR
SHOWERS BY ABOUT 21Z TOWARD INTERSTATE 95. BY 00Z...WITH GOOD 850MB
SUBSIDENCE AND PRECIPITABLE WATER VALUES APPROACHING A HALF-INCH OR
LESS...CHANCES FOR SHOWERS BY DUSK ARE BELOW SLIGHT CHANCE. STILL
THE POTENTIAL FOR WIND GUSTS FROM 30 TO 40 MPH THIS AFTERNOON BASED
ON THE BOUNDARY LAYER LAPSE RATES AND WIND FORECAST BY THE 06Z NAM
BUFR SOUNDINGS...WITH WINDS DIMINISHING QUICKLY LATE AS THE GRADIENT
SLACKENS AND NIGHTTIME APPROACHES. WILL REVISIT TEMPERATURES DURING
THE LATE MORNING BASED UPON THE LATEST TRENDS AS THE FRONT PASSES...
WITH THE CURRENT FORECAST ABOVE THE MOS GUIDANCE.
TONIGHT AND SATURDAY...CONDITIONS SHOULD BE MOSTLY CLEAR. CHILLY
TONIGHT WITH LOWS IN THE MID 30S. HIGHS SATURDAY IN THE LOWER TO MID
60S WITH HIGH PRESSURE DOMINATING.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...
THIS TIME FRAME WILL FEATURE A COUPLE UPPER LEVEL DISTURBANCES...THE
FIRST ONE MOVING ACROSS THE REGION LATE SATURDAY AND THE NEXT ONE
LATE SUNDAY. BOTH OF THESE CLIPPER SYSTEMS WILL PUSH COLD FRONTS AND
REINFORCING SHOTS OF COOLER AIR INTO THE AREA. HOWEVER...DUE TO THE
LACK OF MOISTURE WITH BOTH OF THE SYSTEMS...AM EXPECTING THE FRONTAL
PASSAGES TO BE DRY. HIGH TEMPS ON SUNDAY WILL RETURN TO NEAR
SEASONABLE VALUES...GENERALLY UPPER 40S TO LOWER 50S. OVERNIGHT LOWS
ON SATURDAY NIGHT WILL BE IN THE LOW TO MID 30S...WITH SLIGHTLY
COOLER TEMPS EXPECTED BY SUNDAY NIGHT...GENERALLY THE UPPER 20S TO
LOWER 30S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...
A WARMING TREND WILL ENSUE DURING THE LONG TERM PERIOD. MODELS ARE
IN GOOD AGREEMENT THAT ZONAL FLOW WILL ENCOMPASS MUCH OF THE CONUS
BY THE BEGINNING OF THE WORK WEEK...WHILE AT THE SURFACE...HIGH
PRESSURE WILL PROGRESS ACROSS THE SOUTHEAST AND EVENTUALLY MOVE
OFFSHORE BY THE MIDDLE OF THE WEEK. AS A RESULT...SOUTHERLY FLOW
WILL RETURN TO THE REGION BY EARLY TUESDAY. THIS IN TURN WILL ALLOW
OUR TEMPS TO MODERATE AND AFTER NEAR SEASONABLE HIGHS ON MONDAY
(UPPER 40 TO LOW 50S)...MAX TEMPS WILL RISE WELL INTO THE 60S AGAIN
BY WEDNESDAY.
OUR NEXT SYSTEM IS EXPECTED TO IMPACT THE AREA SOMETIME MID TO LATE
WEEK...HOWEVER THERE IS LITTLE RUN TO RUN CONSISTENCY...AS WELL AS
SIGNIFICANT DISCREPANCIES BETWEEN THE MODELS. THEREFORE...WILL
MAINTAIN FORECAST CONSISTENCY AND GO NO HIGHER THAN SLIGHT CHANCE
POPS FOR THE LATE WEDNESDAY/THURSDAY TIME FRAME.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 915 AM FRIDAY...
24-HR TAF PERIOD:
A COLD FRONT WILL MOVE THROUGH THE REGION TODAY. A BAND OF
SHOWERS WITH BRIEF GUSTY WINDS TO 35KT AND HEAVY RAIN FOR 20 TO 30
MINUTES WILL ACCOMPANY THE BAND. EXPECT THE FRONT AND ANY
LINGERING SHOWERS AND ASSOCIATED LOWER CIGS/VSBYS TO BECOME VFR
CIGS/VSBYS BY AFTERNOON...WITH SCATTERED SHOWERS ACCOMPANYING THE
MAIN FRONT. WINDS WILL SHIFT TO THE WEST AT 15-25KT WITH GUSTS TO
30KT BEHIND THE FRONT...AND CONTINUE THROUGH THE DAY...DIMINISHING
QUICKLY LATE TODAY WITH THE THREAT OF SHOWERS ENDING LAST TOWARD
KRWI AROUND 21Z.
LOOKING AHEAD:
WINDS WILL QUICKLY WEAKEN AND BECOME LIGHT/VARIABLE BY OR SHORTLY
AFTER SUNSET FRIDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM
THE WEST. THERE IS RELATIVELY HIGH CONFIDENCE THAT DRY/VFR
CONDITIONS WILL RULE FRIDAY NIGHT THROUGH EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SEC
NEAR TERM...DJF/BADGETT
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...DJF/BADGETT
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
257 PM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY. WIND GUSTS TO 30 KTS POSSIBLE
SATURDAY.
RATZER
//DISCUSSION...UPDATED 18Z...
SURFACE HIGH PRESSURE RIDGE MOVING ACROSS THE FORECAST AREA THIS
AFTERNOON...ALLOWING LIGHT NORTHWEST WINDS TO BACK SOUTHWEST. NEXT
WEATHER SYSTEM QUICKLY APPROACHING HOWEVER...IN THE FORM OF MID
LEVEL DISTURBANCE TRACKING SOUTHEAST OUT OF THE DAKOTAS AND
MISSOURI VALLEY REGION. SNOW ALREADY SPREADING ACROSS WESTERN AND
PARTS OF CENTRAL IOWA AT THIS HOUR...AND WILL CONTINUE TO SPREAD
INTO ILLINOIS THIS EVENING. PREVIOUS FORECAST APPEARS TO HAVE THIS
WELL IN HAND...WITH LITTLE OVERALL CHANGE NOTED IN 12Z MODEL RUNS.
IF ANYTHING...MAY HAVE TO WATCH FOR A LITTLE EARLIER ONSET. SYSTEM
MOVES THROUGH QUICKLY OVERNIGHT...WITH PERHAPS AN INCH OR SO OF
ACCUMULATION AND A BRIEF PERIOD OF IFR VSBY A LITTLE LESS THAN A
MILE. SNOW SHOULD BE EXITING STAGE RIGHT PRIOR TO SUNRISE
SATURDAY...WITH CEILINGS SCATTERING OUT RATHER QUICKLY DURING THE
EARLY MORNING HOURS.
AFTER THE SNOW...WINDS WILL BECOME GUSTY FROM THE WEST-NORTHWEST
SATURDAY MORNING AS COLDER AIR PUSHES INTO THE REGION. BETWEEN A
RELATIVELY TIGHT PRESSURE GRADIENT AND DEEP MIXING DUE TO COLD
ADVECTION...FORECAST SOUNDINGS INDICATE WINDS GUSTING TO 30 KTS BY
LATE MORNING/MIDDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN WIND TRENDS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
257 PM...ACTIVE PATTERN WITH SEVERAL SYSTEMS TO CONTINUE INTO NEXT
WEEK. LOW PRESSURE OVER MN THIS AFTERNOON WILL MOVE EAST AND CROSS
NORTHERN LAKE MICHIGAN LATE TONIGHT INTO EARLY SATURDAY MORNING.
THIS LOW IS RIDING A COLD FRONT TRAILING A MUCH STRONGER LOW NEAR
HUDSON BAY. AS THIS LOW AND ASSOCIATED FRONT APPROACH THE LAKE
THIS EVENING WESTERLY WINDS WILL SHIFT SOUTHWESTERLY AND STEADILY
INCREASE...THEN SHIFT WESTERLY AS THE FRONT ARRIVES BEFORE SUNRISE
SATURDAY. COLDER AIR SPREADING ACROSS THE REGION COMBINED WITH A
TIGHTENING GRADIENT SHOULD ALLOW GALES TO DEVELOP AROUND SUNRISE
ACROSS THE SOUTHERN HALF OR SO OF THE LAKE. WHILE THE GRADIENT
DOES TIGHTEN OVER NORTHERN LAKE MICHIGAN...IT APPEARS WINDS WILL
ONLY INCREASE TO 30 KTS OR SO. THE GRADIENT THEN RELAXES SOME
SATURDAY EVENING...AS ANOTHER WEAK LOW DEVELOPS OVER WI SATURDAY
EVENING. THIS LOW WILL MOVE ACROSS NORTH/CENTRAL LAKE MICHIGAN
EARLY SUNDAY MORNING WITH ANOTHER PERIOD OF STRONGER WINDS...
PERHAPS UP TO 30 KTS ON THE BACK SIDE OF THIS LOW ON SUNDAY.
ANOTHER FAST MOVING RIDGE MOVES ACROSS THE WESTERN LAKES SUNDAY
EVENING...AS ANOTHER STRONG LOW MOVES ACROSS THE UPPER MIDWEST AND
NORTHERN LAKES MONDAY AFTERNOON INTO MONDAY NIGHT. SOUTHERLY WINDS
WILL INCREASE MONDAY...AHEAD OF THIS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...4 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
202 PM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY. WIND GUSTS TO 30 KTS POSSIBLE
SATURDAY.
RATZER
//DISCUSSION...UPDATED 18Z...
SURFACE HIGH PRESSURE RIDGE MOVING ACROSS THE FORECAST AREA THIS
AFTERNOON...ALLOWING LIGHT NORTHWEST WINDS TO BACK SOUTHWEST. NEXT
WEATHER SYSTEM QUICKLY APPROACHING HOWEVER...IN THE FORM OF MID
LEVEL DISTURBANCE TRACKING SOUTHEAST OUT OF THE DAKOTAS AND
MISSOURI VALLEY REGION. SNOW ALREADY SPREADING ACROSS WESTERN AND
PARTS OF CENTRAL IOWA AT THIS HOUR...AND WILL CONTINUE TO SPREAD
INTO ILLINOIS THIS EVENING. PREVIOUS FORECAST APPEARS TO HAVE THIS
WELL IN HAND...WITH LITTLE OVERALL CHANGE NOTED IN 12Z MODEL RUNS.
IF ANYTHING...MAY HAVE TO WATCH FOR A LITTLE EARLIER ONSET. SYSTEM
MOVES THROUGH QUICKLY OVERNIGHT...WITH PERHAPS AN INCH OR SO OF
ACCUMULATION AND A BRIEF PERIOD OF IFR VSBY A LITTLE LESS THAN A
MILE. SNOW SHOULD BE EXITING STAGE RIGHT PRIOR TO SUNRISE
SATURDAY...WITH CEILINGS SCATTERING OUT RATHER QUICKLY DURING THE
EARLY MORNING HOURS.
AFTER THE SNOW...WINDS WILL BECOME GUSTY FROM THE WEST-NORTHWEST
SATURDAY MORNING AS COLDER AIR PUSHES INTO THE REGION. BETWEEN A
RELATIVELY TIGHT PRESSURE GRADIENT AND DEEP MIXING DUE TO COLD
ADVECTION...FORECAST SOUNDINGS INDICATE WINDS GUSTING TO 30 KTS BY
LATE MORNING/MIDDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN WIND TRENDS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 3 PM FRIDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...4 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1117 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY. WIND GUSTS TO 30 KTS POSSIBLE
SATURDAY.
RATZER
//DISCUSSION...UPDATED 18Z...
SURFACE HIGH PRESSURE RIDGE MOVING ACROSS THE FORECAST AREA THIS
AFTERNOON...ALLOWING LIGHT NORTHWEST WINDS TO BACK SOUTHWEST. NEXT
WEATHER SYSTEM QUICKLY APPROACHING HOWEVER...IN THE FORM OF MID
LEVEL DISTURBANCE TRACKING SOUTHEAST OUT OF THE DAKOTAS AND
MISSOURI VALLEY REGION. SNOW ALREADY SPREADING ACROSS WESTERN AND
PARTS OF CENTRAL IOWA AT THIS HOUR...AND WILL CONTINUE TO SPREAD
INTO ILLINOIS THIS EVENING. PREVIOUS FORECAST APPEARS TO HAVE THIS
WELL IN HAND...WITH LITTLE OVERALL CHANGE NOTED IN 12Z MODEL RUNS.
IF ANYTHING...MAY HAVE TO WATCH FOR A LITTLE EARLIER ONSET. SYSTEM
MOVES THROUGH QUICKLY OVERNIGHT...WITH PERHAPS AN INCH OR SO OF
ACCUMULATION AND A BRIEF PERIOD OF IFR VSBY A LITTLE LESS THAN A
MILE. SNOW SHOULD BE EXITING STAGE RIGHT PRIOR TO SUNRISE
SATURDAY...WITH CEILINGS SCATTERING OUT RATHER QUICKLY DURING THE
EARLY MORNING HOURS.
AFTER THE SNOW...WINDS WILL BECOME GUSTY FROM THE WEST-NORTHWEST
SATURDAY MORNING AS COLDER AIR PUSHES INTO THE REGION. BETWEEN A
RELATIVELY TIGHT PRESSURE GRADIENT AND DEEP MIXING DUE TO COLD
ADVECTION...FORECAST SOUNDINGS INDICATE WINDS GUSTING TO 30 KTS BY
LATE MORNING/MIDDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN WIND TRENDS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 3 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1011 AM CST FRI JAN 27 2012
.DISCUSSION...
333 AM CST
FOR TODAY...CLOUDS ON THE BACKSIDE OF THE LOW THAT IS LIFTING OUT OF
THE OHIO VALLEY...WILL CONTINUE TO CHARGE TO THE SOUTHEAST. AIRCRAFT
SOUNDINGS OUT OF ORD SHOW A FAIRLY SHALLOW SATURATED LAYER REMAINING.
UPSTREAM SOUNDINGS AND RUC ANALYSIS SHOW AN OVERALL DRYING TREND
TO CONTINUE AND NOT EXPECTING ANY EXPANSION TO THE CLOUDS EARLY
THIS MORNING. MOST LOCATIONS SHOULD SEE MOSTLY SUNNY AND BLUE
SKIES...WITH THE EXCEPTION OF THE FAR SOUTHEAST WHERE THEY WILL BE
SLUGGISH. BOTH THE RUC AND NARRE-TL GUIDANCE ARE IN AGREEMENT THAT
THE NORTHWEST SHOULD BE CLEAR BY SUNRISE...WITH THE CHICAGO METRO
A FEW HOURS BEYOND. FAST ON THE HEELS OF THE CLEAR SKIES WILL BE
MID LEVEL CLOUDS ARRIVING FROM THE WEST WITH THE NEXT WAVE MOVING
IN...AND THE ENTIRE CWA IS THEN EXPECTED TO BECOME CLOUDY AGAIN
BY THE EARLY TO MID AFTERNOON. WITH NO REAL CHANGE TO THE AIRMASS
TODAY AND TONIGHT...TEMPERATURES ARE EXPECTED TO BE CLOSE TO
CARBON COPIES OF YESTERDAY. FOCUS IN THE EVENING WILL THEN TURN
TOWARDS THE WEST AS A WEAK CLIPPER /THAT IS NOTED ON REGIONAL
RADAR THIS MORNING ACROSS THE NORTHERN DAKOTAS/ AND A WEAK
SOUTHERN STREAM SYSTEM /NEAR THE OKLAHOMA PAN HANDLE THIS MORNING/
SHIFT EAST AND NOT QUITE MERGE...RATHER COMPLICATE THE EVENING
FORECAST. THE GOOD NEWS IS THAT THE TIMING SHOULD BE AS RUSH HOUR
COMES TO A CLOSE FOR THE FAR NORTHWEST...AND HOURS BEYOND THE
CHICAGO METRO RUSH.
THE OVERALL PICTURE HAS BEEN PRETTY CONSISTENT THE LAST FEW DAYS
THAT ANYWHERE FROM AN INCH TO INCH AND A HALF OF SNOW ARE EXPECTED
WITH THIS SYSTEM. THE EARLIER 18/00Z GUIDANCE SEEMED TO BE IN DECENT
AGREEMENT WITH KEEPING THE BEST FORCING NORTH AND HAVING A BIT MORE
OF A UNIFORM TOTAL ACROSS THE AREA...WITH POTENTIALLY HIGHER AMOUNTS
NORTH OF I-80...BUT THE 00Z GFS AND ECMWF BEGAN TO THROW A WRENCH
AND GIVE THE SOUTHERN SECTION A LITTLE MORE GUSTO THAN PREVIOUS
RUNS...MAKING THE SNOW FALL A LITTLE MORE DISJOINTED. WITH DRY AIR
INVADING THE REGION THIS MORNING...IT WILL TAKE SOME TIME TO
SATURATE THE COLUMN BEFORE IT PRECIPITATES TO THE GROUND. THE OTHER
QUESTION WILL BE ON WHAT FORM THE PRECIP WILL BE AT THE ONSET.
FORECAST SOUNDINGS ARE TRYING TO HOLD ONTO SURFACE TEMPERATURES AT
OR SLIGHTLY ABOVE FREEZING THROUGH ROUGHLY 9 TO 10 PM
TONIGHT...CONTINUING TO COOL BEYOND AND INTO THE OVERNIGHT HOURS.
SIMPLE CROSS HAIRS TECHNIQUE SHOWS THE HIGHEST OMEGA VALUES
INTERSECTING THE DGZ IN A 2 OR SO HOUR WINDOW...AND GENERALLY IN THE
3-4-5Z TIME FRAME. IT IS WITHIN THIS WINDOW THAT THE BEST
ACCUMULATION SHOULD HAPPEN...BUT NOT ANTICIPATING MUCH BEYOND A HALF
INCH AN HOUR RATE WHEN THE ATMOSPHERE IS MOST EFFICIENT...AND WILL
LIKELY START AS A HEAVIER/WET SNOW. STILL CONFIDENT THAT THE
TOTALS WILL BE LOW AND IN THE GENERAL INCH TO MAYBE CLOSE TO AN
INCH AND A HALF/TWO INCH RANGE FOR SOME LOCATIONS. THE SYSTEM WILL
BE FAST MOVING AND GENERALLY TO THE EAST BY THE MORNING.
THE COOLING TREND WILL CONTINUE INTO THE WEEKEND UNDER GENERAL
NORTHWEST FLOW. THE NEXT WIGGLE IN THE FLOW WILL COME SHOOTING
ACROSS THE DAKOTAS AND BRING THE CHANCE OF SNOW TO THE ILLINOIS AND
WISCONSIN BORDER OVERNIGHT TOMORROW. MOISTURE IS LACKING WITH THIS
SYSTEM AND GENERALLY ANTICIPATING A DUSTING TO A SMIDGEN MORE FARTHER
NORTH...TYPICALLY NORTH OF THE I-88 DIVISION LINE. WITH FAIRLY FRESH
SNOW...AND ON AND OFF CLOUDS THROUGH THE WEEKEND...ONLY EXPECTING
TEMPERATURES TO DECREASE SLIGHTLY AND NOT NOSEDIVE. SUNDAY HIGHS
WILL GENERALLY RANGE FROM THE LOWER 30S TO MIDDLE 20S...WITH
OVERNIGHT LOWS 10 OR SO DEGREES BELOW THE AFTERNOON HIGHS.
THE EXTENDED FORECAST IS STILL MODERATELY LOW WITH RESPECT TO
OVERALL CONFIDENCE. ANOTHER WEAK CLIPPER WILL SLIDE ACROSS WISCONSIN
MONDAY AND BRUSH THE EXTREME NORTHERN COUNTIES. BUT THERE ARE STILL
CONSIDERABLE DIFFERENCES BETWEEN THE EC AND GFS...WITH THE GFS BEING
A LITTLE MORE BULLISH WITH THE 00Z RUN. THE BIGGEST ISSUE IN
ADJUSTING POPS UP OR DOWN IS THE FACT THAT THE GFS HAS BEEN FLOPPING
EVERY RUN WITH WHERE THE BEST AXIS LINES UP...AND THE ECMWF REMAINS
CONSISTENT AND MOVES THE NEXT SYSTEM THROUGH OUR AREA COMPLETELY
DRY. TRENDS BEYOND INDICATE A DECENT THERMAL RIDGE ALOFT BUILDING
IN FROM THE WEST...BRINGING HIGHS TUESDAY AND INTO WEDNESDAY INTO
THE MIDDLE AND UPPER 40S...TO EVEN LOWER 50S SOUTH. BY THE
EVENING...A SYSTEM WILL IMPACT THE REGION. THE DIFFERENCES AT 120
HOURS OUT ARE FROM DRY /ECMWF/ TO WET /GFS/ AND ENSEMBLE GUIDANCE
LEAVES CONFIDENCE TO GAIN. FOR NOW...WILL LEAVE ONLY CONTINUE WITH
A SLIGHTS MENTION.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* ACCUMULATING SNOW WITH TEMPORARY VISIBILITY UNDER 1SM TONIGHT.
* INCREASING GUSTY WINDS TONIGHT AFTER 03Z FROM THE WEST SOUTHWEST
BECOMING NORTHWEST INTO SATURDAY. WIND GUSTS TO 30 KTS POSSIBLE
SATURDAY.
RATZER
//DISCUSSION...UPDATED 12Z...
THE DAYTIME PERIOD IS EXPECTED TO BE QUIET AVIATION-WISE
TODAY...BUT SOME CLOUDS PRIOR TO DAYBREAK AND SOME SNOW TONIGHT
ARE THE FORECAST CHALLENGES. THE 020-030 CIGS THIS MORNING WILL
CONTINUE TO DEPART AS A BRIEF AND WEAK HIGH PRESSURE RIDGE AND
DRIER LOW-LEVEL AIR MASS SPREAD INTO THE AREA. WINDS WILL REMAIN
NORTHWEST THIS MORNING BEFORE BACKING TO THE SOUTHWEST FROM 17Z
THROUGH 22Z. AN UPPER LEVEL DISTURBANCE WILL MOVE OVER THE AREA
TONIGHT...LEADING TO SNOWFALL BY MID-EVENING AT ALL TAF SITES. IT
IS POSSIBLE THE START TIME IS SLIGHTLY EARLIER AT EACH AIRPORT
THAN PRESENTLY FORECAST. THE FORCING AND DEEPER MOISTURE FOR SNOW
IS FAIRLY PROGRESSIVE...SO THE WINDOW FOR IFR VISIBILITY AND MVFR
CIGS IN SNOW LOOKS TO BE THREE TO FIVE HOURS. THE CIGS ARE FAVORED
TO LAST SLIGHTLY AFTER THE ACCUMULATING SNOW ENDS...AND SO MIGHT
SOME FLURRIES. TOTAL ACCUMULATION AT AREA TAF SITES IS EXPECTED TO
BE BETWEEN ONE AND TWO INCHES AT THIS TIME...WITH THE SNOW
INITIALLY BEING WET AND THEN BECOMING MORE DRY AS IT WRAPS UP. IN
ADDITION...WINDS WILL BEGIN TO VEER GRADUALLY BACK TOWARDS THE
WEST AND INCREASE IN SPEED ONCE THE SNOW BEGINS THIS EVENING...AND
THEN SHARPLY TO THE NORTHWEST AND BECOME QUITE GUSTY ONCE THE
SYSTEM COLD FRONT PASSES BETWEEN 08Z AND 11Z. SOME SHALLOW BLOWING
SNOW IS LIKELY LATE TONIGHT INTO SATURDAY MORNING. WINDS ARE
FAVORED TO GUST AS HIGH AS 30 KT ON SATURDAY BETWEEN 15Z AND 22Z.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN ACCUMULATING SNOW WITH AT LEAST TEMPORARY
VISIBILITY AT OR JUST UNDER ONE MILE TONIGHT. MEDIUM CONFIDENCE
IN EXACT TIMING. IT MAY NEED TO BE ADJUSTED AN HOUR EARLIER
DEPENDING ON TRENDS TODAY.
* MEDIUM CONFIDENCE IN WIND TRENDS...BUT HIGH CONFIDENCE IN GUSTS
TO 20 KTS LATE TONIGHT AND TO NEAR 30 KTS BY MID MORNING
SATURDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF A DUSTING SNOWFALL OVERNIGHT.
MVFR LIKELY.
SUNDAY...MORNING MVFR THEN CLEARING.
MONDAY...VFR,
TUESDAY...SLIGHT CHANCE OF RAIN...POSSIBLY MIXED WITH SNOW EARLY
AND AGAIN LATE AT NIGHT. IFR POSSIBLE.
WEDNESDAY....MVFR POSSIBLE.
THURSDAY...CHANCE OF SNOW. IFR POSSIBLE.
MTF
&&
.MARINE...
420 AM CST
AN ACTIVE PATTERN MEANS MULTIPLE LOWS WILL BE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN STATES. THIS WILL RESULT IN
REPEATED COLD FRONTAL PASSAGES ACROSS LAKE MI OVER THE NEXT
SEVERAL DAYS.
MODERATELY STRONG NW WINDS THIS MORNING WILL DIMINISH AND BACK TO
OUT OF THE SW AS A RIDGE OF HIGH PRESSURE SLIDES E TO THE UPPER
GREAT LAKES AND LOWER OH VALLEY BY THIS EVENING. WINDS WILL
INCREASE TONIGHT AS A LOW AND COLD FRONT MOVE E INTO THE WESTERN
GREAT LAKES OVERNIGHT.
ANOTHER LOW WILL DROP SE OVER NORTHERN MN BY SAT EVENING. AS IT
CONTINUES ON TO LOWER MI BY DAWN SUN...IT WILL SWEEP ANOTHER COLD
FRONT ACROSS LAKE MI. THIS LOW MOVES E TO NEAR LAKE ONTARIO BY
LATE SUN ALLOWING A RIDGE OF HIGH PRES TO SLIDE E TO THE UPPER
MIDWEST AND MID MS VALLEY SUN. IT CONTINUES MOVING ACROSS THE
UPPER GREAT LAKES TO THE LOWER LAKES AND UPPER OH VALLEY BY MON
MORNING.
YET ANOTHER LOW WILL BE MOVING ACROSS NORTHERN MN AND LAKE
SUPERIOR TUE...BRINGING ANOTHER COLD FRONT ACROSS LAKE MI.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 3 PM FRIDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SATURDAY TO 6 PM
SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
100 PM EST FRI JAN 27 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A SERIES OF FRONTS WILL MOVE ACROSS CENTRAL INDIANA DURING THE
UPCOMING WEEK...BRINGING PERIODIC CHANCES FOR PRECIPITATION.
TEMPERATURES WILL START OFF NEAR OR BELOW AVERAGE...BUT WARM TO
ABOVE AVERAGE READINGS BY EARLY NEXT WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
STRATOCU REMAINS STUBBORN AND ONLY GIVING WAY SLOWLY LATE THIS
MORNING...AS BACK EDGE MOVING INTO THE WABASH VALLEY AT THIS TIME.
TEMPS HAVE BEEN HELD IN THE LOWER AND MID 30S ALL MORNING
UNDERNEATH THE THICK STRATOCU DECK.
MAIN CHANGES FOR THIS AFTERNOON FOCUS ON THE LOW CLOUDS AND
SUBSEQUENT IMPACTS TO TEMPS. MOST RECENT RUC DATA SUGGESTIVE THAT
BACK EDGE OF THE CLOUDS WILL LIKELY TAKE A LARGE PART OF THE
AFTERNOON TO MOVE OUT OF MUCH OF THE AREA...AND MAY NOT COMPLETELY
DEPART THE EASTERN COUNTIES BEFORE THE HIGHER CLOUDS AHEAD OF THE
CLIPPER FOR TONIGHT BEGIN ARRIVING FROM THE WEST. HAVE THEREFORE
BEEFED UP CLOUD COVER FOR THE AFTERNOON HOURS AND BUMPED DOWN
TEMPS A DEGREE OR TWO. STILL OPTIMISTIC THAT THE BACK EDGE OF THE
CLOUDS WILL MAKE IT TO THE INDY METRO BY MID AFTERNOON WITH A VERY
BRIEF PERIOD OF FILTERED SUNSHINE AS THE HIGHER CLOUDS MOVE IN
FROM THE WEST.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
FOCUS IS ON CHANCES FOR SNOW THROUGH THE PERIOD. MODELS ARE
SIMILAR ENOUGH THAT A BLEND CAN BE USED FOR MOST FEATURES.
ISENTROPIC LIFT RAMPS UP LATER THIS EVENING AND OVERNIGHT AHEAD OF
AN APPROACHING FRONT. THIS LIFT PLUS AVAILABLE MOISTURE WILL LEAD
TO PRECIPITATION ACROSS MUCH OF THE AREA. THUS WENT ABOVE MOS POPS
AND CONTINUED LIKELY POPS ACROSS THE NORTHERN 2/3 OF THE FORECAST
AREA WITH CHANCE POPS SOUTH.
BASED ON MODEL SOUNDINGS IT LOOKS LIKE THE SOUTHERN FORECAST AREA
COULD SEE A MIX OF RAIN AND SNOW UNTIL LATER TONIGHT WHEN ALL SNOW
CAN BE EXPECTED. ACROSS THE NORTH...SNOW LOOKS TO BE THE
PRECIPITATION TYPE. BASED ON EXPECTED QPF HAVE LOWERED SNOW
AMOUNTS A BIT...WITH AROUND 1 INCH EXPECTED NORTH TO 1/2 TO 1 INCH
CENTRAL TO A FEW TENTHS SOUTH DUE TO MIXING WITH RAIN.
WITH CLOUDS AND PRECIPITATION AROUND...STUCK CLOSER TO THE WARMER
MAV NUMBERS FOR LOWS TONIGHT.
COLDER AIR WILL MOVE INTO THE AREA ON SATURDAY. A DECENT PRESSURE
GRADIENT WILL LEAD TO WINDY CONDITIONS WITH GUSTS NEAR 30KT
POSSIBLE. THE WINDS SHOULD BRING IN ENOUGH DRY AIR FOR PARTLY
CLOUDY SKIES. A MOS BLEND LOOKS GOOD FOR TEMPERATURES GIVEN
EXPECTED CONDITIONS.
YET ANOTHER FRONT WILL APPROACH AND MOVE INTO THE AREA SATURDAY
NIGHT AND SUNDAY WITH A BRIEF SHOT OF COLD AIR BEHIND IT. THERE
WILL BE SOME DECENT LIFT AS SHOWN BY Q-VECTOR CONVERGENCE...BUT
THERE MAY NOT BE AS MUCH MOISTURE WITH THIS SYSTEM AS THE ONE
BEFORE IT. THUS WILL ONLY GO LOW POPS ON SUNDAY. THERMAL PROFILES
SHOW SNOW AS THE PRECIPITATION TYPE. THERE WILL BE GUSTY WINDS
AGAIN ON SUNDAY WITH A CONTINUED TIGHT PRESSURE GRADIENT AROUND.
DRIER AIR WILL QUICKLY MOVE IN FOR SUNDAY NIGHT PROVIDING DRY
CONDITIONS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LONG RANGE MODELS HAVING SOME TIMING DIFFERENCES WITH SYNOPTIC
DETAILS AS WELL AS QPF...SO DID NOT FEEL COMFORTABLE CHANGING THE
CENTRAL REGION EXTENDED. ONE FRONTAL SYSTEM IS EXPECTED TO BRING A
CHANCE OF RAIN IN BY TUESDAY AND LINGER INTO OUR SOUTHEAST ON
WEDNESDAY MORNING. THEN...ANOTHER SYSTEM WILL BRING RAIN CHANCES
INTO THE SOUTHWEST WEDNESDAY NIGHT AND ACROSS ALL OF CENTRAL INDIANA
THURSDAY. COULD SEE A MIX OF RAIN AND SNOW OVERNIGHT WEDNESDAY
NIGHT...OTHERWISE...MILD TREND TO CONTINUE AS HAS BEEN THE CASE MOST
OF THE WINTER WITH QUASI-ZONAL FLOW ALOFT KEEPING THE COLDER
CANADIAN AIR NORTH OF THE OHIO VALLEY. DAYTIME HIGHS IN THE 40S
ANTICIPATED WITH 50S ACROSS PARTS OF SOUTH CENTRAL INDIANA TUESDAY
THROUGH WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR THE 27/18Z TAF ISSUANCE/...
CLEARING LINE OF PERSISTENT CLOUD DECK IS ENTERING KLAF AND WILL
MOVE ACROSS REMAINING TAF SITES OVER THE NEXT FEW HOURS.
ANTICIPATE RETURN TO VFR CONDITIONS AT ALL TAF SITES BY MID
AFTERNOON. HOWEVER...HIGH CLOUDS WILL QUICKLY BUILD INTO THE AREA
AS A QUICK CLIPPER SYSTEM MOVES CLOSER. THIS SYSTEM WILL PRODUCE
SNOW AT KIND AND KLAF...AND MAINLY A RAIN/SNOW MIX AT KHUF AND
KBMG AFTER SAT 06Z CAUSING MVFR/IFR CONDITIONS. THIS
DISTURBANCE WILL EXIT QUICKLY THOUGH...AND PRECIP WILL COME TO
AN END BY DAYBREAK TOMORROW. MVFR CONDITIONS WILL LINGER UNTIL MID
MORNING TOMORROW...AND THEN BACK TO VFR BY LATE MORNING AS CLOUDS
SCATTER OUT.
WEST WINDS WILL INCREASE AROUND DAYBREAK TOMORROW AND WILL BECOME
STRONGER THROUGH THE COURSE OF THE DAY. SUSTAINED SPEEDS WILL
RANGE FROM 15 TO 20 KTS WITH GUSTS UP TO 30 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1114 AM EST FRI JAN 27 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A SERIES OF FRONTS WILL MOVE ACROSS CENTRAL INDIANA DURING THE
UPCOMING WEEK...BRINGING PERIODIC CHANCES FOR PRECIPITATION.
TEMPERATURES WILL START OFF NEAR OR BELOW AVERAGE...BUT WARM TO
ABOVE AVERAGE READINGS BY EARLY NEXT WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
STRATOCU REMAINS STUBBORN AND ONLY GIVING WAY SLOWLY LATE THIS
MORNING...AS BACK EDGE MOVING INTO THE WABASH VALLEY AT THIS TIME.
TEMPS HAVE BEEN HELD IN THE LOWER AND MID 30S ALL MORNING
UNDERNEATH THE THICK STRATOCU DECK.
MAIN CHANGES FOR THIS AFTERNOON FOCUS ON THE LOW CLOUDS AND
SUBSEQUENT IMPACTS TO TEMPS. MOST RECENT RUC DATA SUGGESTIVE THAT
BACK EDGE OF THE CLOUDS WILL LIKELY TAKE A LARGE PART OF THE
AFTERNOON TO MOVE OUT OF MUCH OF THE AREA...AND MAY NOT COMPLETELY
DEPART THE EASTERN COUNTIES BEFORE THE HIGHER CLOUDS AHEAD OF THE
CLIPPER FOR TONIGHT BEGIN ARRIVING FROM THE WEST. HAVE THEREFORE
BEEFED UP CLOUD COVER FOR THE AFTERNOON HOURS AND BUMPED DOWN
TEMPS A DEGREE OR TWO. STILL OPTIMISTIC THAT THE BACK EDGE OF THE
CLOUDS WILL MAKE IT TO THE INDY METRO BY MID AFTERNOON WITH A VERY
BRIEF PERIOD OF FILTERED SUNSHINE AS THE HIGHER CLOUDS MOVE IN
FROM THE WEST.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
FOCUS IS ON CHANCES FOR SNOW THROUGH THE PERIOD. MODELS ARE
SIMILAR ENOUGH THAT A BLEND CAN BE USED FOR MOST FEATURES.
ISENTROPIC LIFT RAMPS UP LATER THIS EVENING AND OVERNIGHT AHEAD OF
AN APPROACHING FRONT. THIS LIFT PLUS AVAILABLE MOISTURE WILL LEAD
TO PRECIPITATION ACROSS MUCH OF THE AREA. THUS WENT ABOVE MOS POPS
AND CONTINUED LIKELY POPS ACROSS THE NORTHERN 2/3 OF THE FORECAST
AREA WITH CHANCE POPS SOUTH.
BASED ON MODEL SOUNDINGS IT LOOKS LIKE THE SOUTHERN FORECAST AREA
COULD SEE A MIX OF RAIN AND SNOW UNTIL LATER TONIGHT WHEN ALL SNOW
CAN BE EXPECTED. ACROSS THE NORTH...SNOW LOOKS TO BE THE
PRECIPITATION TYPE. BASED ON EXPECTED QPF HAVE LOWERED SNOW
AMOUNTS A BIT...WITH AROUND 1 INCH EXPECTED NORTH TO 1/2 TO 1 INCH
CENTRAL TO A FEW TENTHS SOUTH DUE TO MIXING WITH RAIN.
WITH CLOUDS AND PRECIPITATION AROUND...STUCK CLOSER TO THE WARMER
MAV NUMBERS FOR LOWS TONIGHT.
COLDER AIR WILL MOVE INTO THE AREA ON SATURDAY. A DECENT PRESSURE
GRADIENT WILL LEAD TO WINDY CONDITIONS WITH GUSTS NEAR 30KT
POSSIBLE. THE WINDS SHOULD BRING IN ENOUGH DRY AIR FOR PARTLY
CLOUDY SKIES. A MOS BLEND LOOKS GOOD FOR TEMPERATURES GIVEN
EXPECTED CONDITIONS.
YET ANOTHER FRONT WILL APPROACH AND MOVE INTO THE AREA SATURDAY
NIGHT AND SUNDAY WITH A BRIEF SHOT OF COLD AIR BEHIND IT. THERE
WILL BE SOME DECENT LIFT AS SHOWN BY Q-VECTOR CONVERGENCE...BUT
THERE MAY NOT BE AS MUCH MOISTURE WITH THIS SYSTEM AS THE ONE
BEFORE IT. THUS WILL ONLY GO LOW POPS ON SUNDAY. THERMAL PROFILES
SHOW SNOW AS THE PRECIPITATION TYPE. THERE WILL BE GUSTY WINDS
AGAIN ON SUNDAY WITH A CONTINUED TIGHT PRESSURE GRADIENT AROUND.
DRIER AIR WILL QUICKLY MOVE IN FOR SUNDAY NIGHT PROVIDING DRY
CONDITIONS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LONG RANGE MODELS HAVING SOME TIMING DIFFERENCES WITH SYNOPTIC
DETAILS AS WELL AS QPF...SO DID NOT FEEL COMFORTABLE CHANGING THE
CENTRAL REGION EXTENDED. ONE FRONTAL SYSTEM IS EXPECTED TO BRING A
CHANCE OF RAIN IN BY TUESDAY AND LINGER INTO OUR SOUTHEAST ON
WEDNESDAY MORNING. THEN...ANOTHER SYSTEM WILL BRING RAIN CHANCES
INTO THE SOUTHWEST WEDNESDAY NIGHT AND ACROSS ALL OF CENTRAL INDIANA
THURSDAY. COULD SEE A MIX OF RAIN AND SNOW OVERNIGHT WEDNESDAY
NIGHT...OTHERWISE...MILD TREND TO CONTINUE AS HAS BEEN THE CASE MOST
OF THE WINTER WITH QUASI-ZONAL FLOW ALOFT KEEPING THE COLDER
CANADIAN AIR NORTH OF THE OHIO VALLEY. DAYTIME HIGHS IN THE 40S
ANTICIPATED WITH 50S ACROSS PARTS OF SOUTH CENTRAL INDIANA TUESDAY
THROUGH WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR THE 27/15Z TAF UPDATE/...
UPDATE...
CONDITIONS HAVE BEEN SLOW TO IMPROVE. IFR CATEGORY CONDITIONS
CONTINUE TO LINGER AT KIND AND WILL MOST LIKELY DO SO THROUGH
LATE MORNING. ORIGINAL THINKING WAS THAT VFR CONDITIONS WOULD
RETURN BY EARLY AFTERNOON...BUT THAT MAY HAVE BEEN TOO OPTIMISTIC.
ANTICIPATE MVFR CONDITIONS FOR THE FIRST PART OF THE
AFTERNOON...AND THEN VFR LATER TODAY.
PREVIOUS DISCUSSION...
CONDITIONS HAVE IMPROVED TO MVFR AND SHOULD REMAIN SO THIS MORNING.
SHOULD SEE ONLY SCATTERED VFR CU AND A BROKEN AC DECK AFTER 16Z AT
LAF AND HUF AND 18Z AT IND AND BMG AS THE CLEARING LINE ACROSS
EASTERN ILLINOIS PROGRESSES EASTWARD. A COLD FRONT WILL THEN BRING
SOME LIGHT SNOW TO IND AND LAF AND RAIN OR SNOW TO HUF AND BMG AFTER
04Z BRINGING MVFR CEILINGS OR WORSE IN. FINALLY...WINDS WILL SHIFT
FROM NORTHWEST AROUND 10 KNOTS TODAY TO SOUTHWEST LESS THAN 10 KNOTS
TONIGHT AND INCREASE TO WEST AT 15 KNOTS AND GUSTING TO 22 KNOTS AT
FROPA WHICH SHOULD BE AROUND 10Z AT LAF AND HUF TO 12Z AT IND AND
BMG. THE PRECIPITATION SHOULD ALSO END AT FROPA.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...MK/TDUD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1129 AM CST FRI JAN 27 2012
.AVIATION...
FOR THE 18Z TAF ISSUANCE...
A COLD FRONT HAS MOVED ACROSS THE TAF SITES THIS MORNING SHIFTING
THE WINDS TO THE NORTH. SUSTAINED WINDS OF 25 TO 35 KNOTS ARE
ANTICIPATED INTO THE LATE AFTERNOON WITH SOME GUSTS OVER 40 KNOTS.
MID TO HIGH LEVEL CLOUDS HAVE DEVELOPED BEHIND THIS FRONT AND ARE
ANTICIPATED TO CREATE MOSTLY CLOUDY SKIES THROUGH EARLY THIS
EVENING. CLEARING SKIES AND DECREASED WIND SPEEDS ARE EXPECTED
OVERNIGHT TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 607 AM CST FRI JAN 27 2012/
SYNOPSIS...
IN APPLYING THE FORECAST FUNNEL, ONE WOULD START WITH THE 27.00Z 300
HPA SYNOPTIC MAP. A 100 KT JET EXTENDED FROM KMFR TO KLBF. THIS JET
WAS WELL UPSTREAM OF A HIGHLY AMPLIFIED MERIDIONAL TROUGH AXIS THAT
EXTENDED FROM ONTARIO INTO THE GULF OF MEXICO. A FASTER 135 TO 140 KT
JET LOCATED EAST OF THIS TROUGH AXIS ACROSS THE EASTERN UNITED STATES.
AT 500 HPA, A SHORTWAVE TROUGH WAS MOVING ACROSS THE NORTHERN ROCKIES.
THIS UPPER LEVEL FEATURE WAS USHERING IN A SURFACE COLD FRONT ACROSS
THE NORTHERN PLAINS AND INTO WYOMING. NOTHING TOO OUT OF THE ORDINARY WAS
OBSERVED AT 700 AND 850 HPA ACROSS THE CENTRAL PLAINS EXCEPT A DRY THERMODYNAMIC
PROFILE.
DISCUSSION...
DAYS 1-2...
TODAY:
FORECAST SOUNDINGS FROM THE 27.00Z GFS AND 27.00Z NAM BOTH AGREE ON
RAPID SATURATION BETWEEN 600 AND 400 HPA IN ASSOCIATION WITH MID LEVEL
MOISTURE ADVECTION AHEAD OF AN APPROACHING UPPER LEVEL SHORTWAVE TROUGH
THIS MORNING. BELOW 600 HPA, ALL MODELS SHOW THE ATMOSPHERIC PROFILE
BECOMING MIXED (PARTICULARLY BELOW 800 HPA) AND AS A RESULT IS RELATIVELY
DRY. WITH THE EXCEPTION OF THE 27.00Z GFS, ALL MODELS BASICALLY HAVE
NO QPF ACROSS SOUTHWEST KANSAS TODAY. ALSO CHECKED THE ARW/NMM/HRRR
WHICH PAINT AN ALMOST NEGLIGIBLE QPF SIGNAL. AS A RESULT, HAVE REDUCED
POPS TO BELOW 15 PERCENT. SOME VIRGA IS POSSIBLE THIS MORNING BUT OTHER
THAN THAT, THE FORECAST WILL REMAIN DRY FOR TODAY.
SECOND SENSIBLE WEATHER CONCERN AND RATHER THE MOST SIGNIFICANT IS WINDS.
AS THE ABOVE MENTIONED SHORTWAVE TROUGH MOVES ACROSS KANSAS, THIS FEATURE
WILL PUSH A SURFACE COLD FRONT ACROSS THE REGION THIS MORNING. IN THE
WAKE OF THE FRONT, A TIGHT PRESSURE GRADIENT AND MIXING FROM ON AVERAGE
800 HPA TO THE SURFACE WILL RESULT IN MOMENTUM TRANSFER FROM THE TOP
OF THE BOUNDARY LAYER TO THE GROUND. BUFKIT SOUNDINGS SHOW ABOUT 40
KT AT THE TOP OF THE MIXING LAYER. AS WITH THE PREVIOUS DAY SHIFT, I
HAVE UTILIZED THE MIXED LAYER WIND SMART TOOL WHICH BROUGHT IT REASONABLE
WINDS SPEEDS INTO THE GRIDS. MOS/LAMP GUIDANCE ALSO SUGGESTS SIMILAR
WIND MAGNITUDE AS OUTPUTTED BY TOOL. THE ONGOING NPW LOOKS VERY REASONABLE
ALTHOUGH I DID ADJUST THE START TIME EARLIER AS THE HRRR MODEL IS SUGGESTING
NEAR CRITERIA WIND SPEEDS AT THE END OF THE MODEL RUN (EARLIER). WINDS
AROUND 29-33 KT WITH GUSTS TO 40-45 KT ARE FORECAST TODAY. WINDS WILL
DECREASE SIGNIFICANTLY TOWARDS SUNSET.
TONIGHT:
HIGH PRESSURE WILL SLIDE ACROSS KANSAS TONIGHT AND INTO TOMORROW MORNING.
FORECAST SOUNDINGS SHOW RAPID DRYING IN THE MID LEVELS AFTER 00Z. WITH
CLEARING SKIES AND RELATIVELY LIGHT WINDS, AM EXPECTING COOL OVERNIGHT
LOWS WITH TEENS TO LOW 20S DEG F ACROSS MUCH OF THE REGION. SUBSIDENCE
AND HIGH PRESSURE IN THE WAKE OF THE DEPARTING TROUGH WILL KEEP POPS
AT ZERO BY 06Z TONIGHT.
SATURDAY/SATURDAY NIGHT:
EXTREMELY QUIET WEATHER IS EXPECTED AS NORTHWESTERLY FLOW ALOFT PREVAILS
ACROSS THE SUNFLOWER STATE THROUGH THE BEGINNING OF THE WEEKEND. MUCH
WEAKER WESTERLY TO NORTHWESTERLY WINDS AROUND 10 TO 15 KT ARE EXPECTED
SATURDAY. TEMPERATURES WILL BE FAIRLY SEASONABLE TO SLIGHT ABOVE
WITH MID TO UPPER 40S DEG F EXPECTED. SKIES SHOULD BE FAIRLY
CLEAR. LOWS INTO SUNDAY MORNING ARE EXPECTED TO BE NEAR NORMAL...LOW
20S DEG F.
DAYS 3-7...
A PROGRESSIVE, ZONAL SYNOPTIC SCALE PATTERN IS EXPECTED TO PREVAIL THROUGH
THE MEDIUM RANGE YIELDING WEAK COLD FRONT PASSAGES AND AN OVERALL CONTINUED
ABOVE-AVERAGE TEMPERATURE FORECAST.
A LEE TROUGH WILL DEVELOP SUNDAY AS AN UPPER LEVEL TROUGH BEGINS TO
ENTER THE PACIFIC NORTHWEST REGION. REMNANT, COOL POLAR AIRMASS OVER
THE CENTRAL CONUS WILL LOSE ITS GRIP WITH INCREASING LOW LEVEL THICKNESSES
AND SUBSEQUENT WARMER TEMPERATURES OVER THE WESTERN PLAINS. HIGHS SUNDAY
SHOULD WARM WELL INTO THE 50S AND HAVE INCREASED THE FORECAST HIGHS
ABOUT 2 TO 3 DEGREES ON AVERAGE ACROSS THE DDC FORECAST AREA.
MONDAY CERTAINLY LOOKS TO BE A WARM DAY WITH THE LEE TROUGH OVER EASTERN
COLORADO AND ADJACENT WESTERN KANSAS DOWN TO ABOUT 1002-1004MB. DEPENDING
ON THE DEGREE OF BOUNDARY LAYER MIXING, A VERY WARM DAY COULD RESULT...ESPECIALLY
ACROSS THE SOUTHWESTERN COUNTIES (HIGHER ELEVATION RESULTING IN BETTER
POTENTIAL FOR DEEPER MIXING). THE ALLBLEND GUIDANCE GIVES HIGHS OF 59-60F
FOR MUCH OF THE FORECAST AREA BUT SOME MID 60S CANNOT BE RULED OUT IN
THIS VERY WARM PATTERN AHEAD OF A LOW AMPLITUDE ZONAL SHORTWAVE TROUGH.
THIS AFOREMENTIONED TROUGH WILL MOVE FAST ACROSS THE CENTRAL PLAINS
MONDAY NIGHT AND TUESDAY SHOULD BE A BIT COOLER...YET STILL QUITE A
BIT ABOVE THE CLIMATOLOGICAL AVERAGE OF LOWER-MID 40S FOR SOUTHWEST
KANSAS TO END THE MONTH OF JANUARY. AFTER THAT...THERE IS SOME UNCERTAINTY
IN HOW THE PATTERN WILL EVOLVE. THE GFS SHOWS AMPLIFICATION TAKING PLACE
QUICKLY OVER THE WESTERN CONUS WITH A RIDGE AXIS OVER THE WEST COAST
AND SUBSEQUENT TROUGH OVER THE CENTRAL CONUS. THIS IS A COOLER PATTERN,
HOWEVER THE NEW ECMWF MODEL SHOWS A MUCH WARMER SCENARIO FOR MID-WEEK
WITH A MUCH LOWER AMPLITUDE RIDGE-TROUGH SETUP OVER THE WESTERN AND
CENTRAL CONUS. THE ECMWF MODEL DOES INDEED AMPLIFY THE SYNOPTIC SCALE
PATTERN RATHER SUBSTANTIALLY BY THURSDAY, RESULTING IN A MEAN TROUGH/LOWER
HEIGHTS OVER THE CENTRAL CONUS...SO THE ABOVE/MUCH ABOVE TEMPERATURES
WE WILL BE SEEING SUNDAY THROUGH WEDNESDAY MAY END BY THURSDAY- FRIDAY
OF NEXT WEEK (FEB 2-3) DEPENDING ON HOW THE AMPLIFICATION OF THE LARGE
SCALE PATTERN EVOLVES OVER THE CONUS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 49 21 56 / 0 0 0 0
GCK 18 47 20 55 / 0 0 0 0
EHA 19 49 23 59 / 0 0 0 0
LBL 18 49 21 57 / 0 0 0 0
HYS 18 47 20 55 / 0 0 0 0
P28 20 49 23 56 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ030-
031-043>046-061>066-074>081-084>090.
&&
$$
FN12/42/42
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1140 AM EST FRI JAN 27 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST PROMPTING A SECONDARY
COASTAL LOW TO DEEPEN ALONG THE NEW ENGLAND COAST THIS
AFTERNOON. THE LOW WILL EXIT INTO THE CANADIAN MARITIMES TONIGHT.
ANOTHER LOW WILL TRACK THROUGH SOUTHERN CANADA SATURDAY NIGHT
WITH A WEAK COLD FRONT CROSSING NORTHERN NEW ENGLAND. ANOTHER
FRONT WILL CROSS NEW ENGLAND SUNDAY NIGHT WITH COLDER TEMPERATURES
BEHIND IT. A WARM FRONT WILL LIFT NORTHWARD INTO NORTHERN NEW
ENGLAND TUESDAY NIGHT AND LOW PRESSURE WILL TRACK ALONG THE WARM
FRONT ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
JUST A QUICK UPDATE TO ADJUST TEMPERATURES AND DEW POINTS AND
EXTEND ADVISORIES ANOTHER 2-3 HOURS AS COLD AIR REMAINS STUBBORN.
THE WARNINGS IN PLACE FOR COOS...OXFORD...FRANKLIN...AND SOMERSET
WERE EXTENDED UNTIL 7 PM AS SREF PROBABILITIES INDICATE FREEZING
RAIN WILL CONTINUE TO BE LIKELY.
&&
.PREVIOUS UPDATE... FREEZING LINE CONTINUES TO CREEP NORTH INTO
CENTRAL GRAFTON AND CARROLL COUNTIES BUT REMAINS MIDWAY THROUGH
CUMBERLAND COUNTY AND SOUTH OF AUGUSTA. WINDS ARE EASTERLY ALONG
THE COAST AND ROCKLAND IS GUSTING TO NEAR 30 MPH. THE BEST
PRESSURE FALLS ARE NEAR BEVERLY MASSACHUSETTS AND IT APPEARS THIS
IS WHERE THE SURFACE LOW WILL REDEVELOP. THIS WILL KEEP THE COLD
AIR OVER OUR AREA LONGER. WILL NEED TO KEEP AN EYE ON THE ENDING
TIMES OF THE ADVISORIES AND WARNINGS. THE HRRR MODEL INDICATES
PRECIPITATION WILL BE WINDING DOWN BY NOON...BUT IF COLD AIR HANGS
ON AND LIGHT PRECIPITATION CONTINUES WE MAY NEED TO EXTEND THE
ADVISORY FOR A COUPLE HOURS. RADAR IMAGERY IS ENCOURAGING WITH A
RELATIVELY ECHO-FREE AREA HEADED OUR WAY. ADJUSTED HIGH
TEMPERATURES DOWN A COUPLE OF DEGREES FOR THIS UPDATE.
$$
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
AFTER SOME PCPN OVER EASTERN AREAS EARLY...CLEARING IS EXPECTED
THIS EVENING AS THE SURFACE LOW PROGRESSES INTO THE CANADIAN
MARITIMES. THIS WILL BE FOLLOWED BY A WEAK RIDGE OF HIGH PRESSURE
LATE TONIGHT. HOWEVER...SOME HIGH...THIN CLOUDINESS WILL ALREADY
BE INVADING THE SKY BY MIDDAY SATURDAY AS A WEAK TROUGH OF LOW
PRESSURE QUICKLY APPROACHES NORTHERN NEW ENGLAND. WITH DRY
ATMOSPHERE IN PLACE IN THE LOWER LEVELS...WE EXPECT ANY PCPN TO
HOLD OFF UNTIL AFTER DARK.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
OVER THE OUTLOOK PERIOD FAST MOVING CLIPPERS WITH VERY LIMITED
MOISTURE WILL BE MOVING THROUGH A RATHER ZONAL WESTERLY FLOW
ALLOWING EXCHANGES IN AIR MASSES ABOUT EVERY 48 HRS. TEMPS WILL
GENERALLY BE AVERAGING ABOVE NORMAL THROUGH MOST OF THE PERIOD.
WITH THAT GENERAL OUTLOOK IN MIND...MORE SPECIFICALLY...A RIDGE OF
HIGH PRESSURE CROSSES THE AREA ON SATURDAY WITH WARMER
TEMPERATURES AND DRY CONDITIONS.
A FAST MOVING CLIPPER MOVES EAST THROUGH ONTARIO AND INTO QUEBEC
LATE SATURDAY INTO SATURDAY NIGHT...SPREADING SCATTERED SNOW
SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND WESTERN MAINE. A
COLD FRONT WILL PUSH THROUGH AS WELL WITH COLDER TEMPERATURES AND
GUSTY WEST WINDS BEHIND IT.
A WEAK RIDGE OF PRESSURE SETTLES OVER THE AREA SUNDAY BUT IS
QUICKLY FOLLOWED BY ANOTHER FAST MOVING CLIPPER THAT WILL MOVE
ACROSS NEW ENGLAND SUNDAY NIGHT WITH A WEAK SURFACE LOW TRACKING
THROUGH SOUTHERN QUEBEC. A FEW MORE LIGHT SNOW SHOWERS WILL BE
POSSIBLE MAINLY IN THE MOUNTAINS. SEASONABLY COLD AIR WILL MOVE IN
FOR MONDAY.
THE FAST FLOW ALOFT CONTINUES THROUGH THE WEEK WITH WAVE AFTER
WAVE CROSSING THROUGH THE FLOW. ANOTHER WAVE APPROACHES ON TUESDAY
WITH A WARM FRONT LIFTING NORTHWARD INTO CENTRAL PARTS OF NEW
HAMPSHIRE AND MAINE BY TUESDAY NIGHT INTO WEDNESDAY. THIS MAY LEAD
TO SOME LIGHT SNOW BUT OVERALL FORCING LOOKS WEAK UNTIL WEDNESDAY
WHEN SURFACE LOW PRESSURE TRACKS EASTWARD ALONG THE WARM FRONT.
BEST PRECIPITATION CHANCES WILL BE FARTHER TO THE NORTH. WARM AIR
IN PLACE SOUTH OF THE WARM FRONT WILL YIELD MOSTLY RAIN AS
PRECIPITATION TYPE...WHILE NORTH OF THE FRONT SNOW IS MORE
LIKELY.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
MAINLY LIFR CONDITIONS...IMPROVING TO VFR THIS EVENING WITH THE
PASSAGE OF THE SURFACE LOW AND A WIND SWITCH TO THE WEST.
LONG TERM...
MOSTLY VFR CONDITIONS EXPECTED. MOST LIKELY TIMES FOR
FLIGHT RESTRICTIONS WILL BE SUNDAY NIGHT AND AGAIN TUESDAY THROUGH
WEDNESDAY.
&&
.MARINE...
SHORT TERM...
HAVE ISSUED A GALE WARNING FOR THE OUTER WATERS THROUGH TONIGHT AS
SURFACE LOW INTENSIFIES...PULLS TO OUR EAST...AND INCREASES THE
GRADIENT AS WELL AS THE COLD AIR ADVECTION.
LONG TERM...
MAY SEE WINDS REACH 30 OR 35 KT BEHIND A COLD FRONT ON
SATURDAY NIGHT. ANOTHER FAST MOVING FRONT WILL CROSS THE WATERS
SUNDAY NIGHT WITH GUSTY WINDS BEHIND IT AS WELL.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ019>022.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
MEZ007>009.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MEZ012>014.
NH...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NHZ005-006.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
NHZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR ANZ151-153.
GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ150-152-154.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
356 PM EST FRI JAN 27 2012
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE AREA THIS
WEEKEND, BRINGING A MIX OF RAIN AND SNOW SHOWERS. HIGH PRESSURE
BUILDING IN FROM THE SOUTHWEST WILL ALLOW FOR A DRY START TO THE
WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB SHORT WAVE
TROUGH AXIS EXTENDING FROM ONTARIO ACROSS THE EASTERN GREAT
LAKES. VORT ENERGY WITH THIS FEATURE HAS MOSTLY SHIFTED NORTHEAST
OF THE AREA. AT THE SURFACE, A 991MB LOW IS LOCATED IN NORTHERN NY
WITH A COLD FRONT EXTENDING SOUTHWARD OF THIS FEATURE. THE COLD
FRONT HAS PUSHED WELL EAST OF THE AREA AHEAD OF THE MID- LEVEL
TROUGH. LINGERING LIGHT RAIN AND SNOW SHOWERS ARE DIMINISHING AS
FORCING SHIFTS NORTHEAST OF THE AREA.
TONIGHT...A WEAK LOW-LEVEL RIDGE WILL BUILD INTO THE AREA WITH DRY
WEATHER EXPECTED AS HIGH PRESSURE BUILDS IN FROM THE SOUTHWEST.
THE NEXT SHORT WAVE WILL APPROACH FROM THE WEST NEAR DAWN,
RETURNING A SCHC OF SNOW SHOWERS BY DAWN ON SATURDAY FOR AREAS
NORTHWEST OF PITTSBURGH. DESPITE THE COLDER AIR MASS IN PLACE,
CLOUD COVERAGE WILL LIMIT RADIATIONAL COOLING TONIGHT, WITH LOWS A
FEW DEGREES WARMER THAN A MAV/MET BLEND, RANGING FROM THE MID 20S
ACROSS THE EASTERN RIDGES TO THE NEAR 30 ACROSS NORTH-CENTRAL WV
AND EASTERN OHIO.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
THE NAM/GFS/ECMWF SHOW AGREEMENT IN BRINGING A LOW PRESSURE SYSTEM
ACROSS THE NORTHERN GREAT LAKES THAT WILL SWEEP A WEAK COLD FRONT
ACROSS THE UPPER OHIO VALLEY ON SATURDAY. PRECIPITATION WITH THE
FRONT WILL BE GENERALLY LESS THAN A TENTH OF AN INCH WITH A LACK OF
DEEP MOISTURE WITH THIS SYSTEM. FOR PRECIP TYPE, NAM/GFS INDICATE
THE 1000-500MB 5400M LINE SOUTH OF THE AREA THROUGHOUT THE DAY,
ALTHOUGH THE 1000-850MB 1300M LINE WILL CREEP NORTH OF THE
MASON-DIXON LINE AND WILL ALLOW FOR MOSTLY RAIN SHOWERS FOR
LOCATIONS SOUTH OF THE PITTSBURGH METRO AND A MIX OF RAIN AND SNOW
NORTHWARD TO THE I-80 CORRIDOR. CHC POPS BEGIN NORTHWEST OF PITTSBURGH
DURING THE MORNING HOURS WITH POPS INCREASING TO LIKELY AS THE FRONT
CROSSES SATURDAY AFTERNOON. THE BEST CHANCE FOR ANY SNOW
ACCUMULATION WILL BE ALONG THE I-80 CORRIDOR, WITH LESS THAN AN INCH
POSSIBLE THERE. FORECAST HIGH TEMPS ARE A FEW DEGREES COOLER THAN A
MAV/MET BLEND AS ONGOING CLOUD COVERAGE WILL BE A LIMITING FACTOR.
HIGHS WILL RANGE FROM THE MID 30S ACROSS THE I-80 CORRIDOR TO THE
LOWER 40S ACROSS NORTH-CENTRAL WV.
SATURDAY NIGHT...A BREAK IS EXPECTED IN RAIN/SNOW SHOWERS AS HIGH
PRESSURE PASSES SOUTH OF THE AREA AND A DEEP LAYER OF DRY AIR BUILDS
IN THROUGH DAWN ON SUNDAY. COLD AIR ADVECTION IN THE WAKE OF THE
FRONT WILL ALLOW LOW TEMPS TO RANGE FROM NEAR 20 ALONG THE I-80
CORRIDOR AND EASTERN RIDGES TO THE MID 20S ELSEWHERE.
SUNDAY THROUGH MONDAY...THERE IS OPERATIONAL MODEL AGREEMENT THAT A
SHORT WAVE TROUGH WILL SWING INTO THE AREA SUNDAY AFTERNOON.
DECREASING THICKNESSES WILL ALLOW FOR PRECIPITATION TO BE MOSTLY IN
THE FORM OF SNOW SHOWERS WITH THIS DISTURBANCE AS IT CROSS THE UPPER
OHIO VALLEY WITH THE POSSIBILITY OF RAIN MIXING IN DURING THE
AFTERNOON FOR AREAS SOUTH OF THE I-70 CORRIDOR. ANY LIGHT SNOW
ACCUMULATION OF AN INCH OR LESS WILL BE LIMITED TO THE I-80
CORRIDOR AND THE EASTERN RIDGES WITH THIS SYSTEM. HIGH PRESSURE
WILL BUILD BACK IN FROM THE SOUTH FOR SUNDAY NIGHT INTO MONDAY,
WITH A DRY FORECAST RETURNING TO BEGIN NEXT WEEK. TEMPERATURES
WILL BE NEAR SEASONAL NORMALS THROUGH THIS PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE WILL MOVE OFF THE SOUTHEASTERN UNITED STATES COAST
TUESDAY...WITH CONDITIONS REMAINING DRY. MODELS ARE IN GOOD
AGREEMENT SHOWING LOW PRESSURE MOVING ACROSS CANADA AND BRINGING A
COLD FRONT ACROSS THE REGION...ALTHOUGH THERE IS SOME DISAGREEMENT
WITH TIMING. AVERAGE TIMING PUTS FRONTAL PASSAGE AROUND
WEDNESDAY...AND HAVE PUT HIGHEST POPS IN THE FORECAST AT THAT TIME.
12Z GFS/ECMWF ARE MORE AGGRESSIVE THAN THEIR 00Z COUNTERPARTS IN
DEVELOPING A LOW ACROSS THE SOUTHEASTERN UNITED STATES...AND MOVING
IT OFFSHORE OF NEW YORK CITY BY FRIDAY MORNING. THIS BRINGS IN POPS
FOR THE EASTERN HALF OF THE REGION THURSDAY INTO FRIDAY...WITH
SLIGHT CHANCE POPS TO THE WEST. TEMPERATURES WILL BE A FEW DEGREES
ABOVE NORMAL DURING THIS TIME PERIOD.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AS OF MID AFTERNOON...ALL SITES ARE MVFR...EXCEPT FOR FKL AND DUJ.
EXPECT THE TWO NORTHERN SITES TO FINALLY REACH MVFR CONDITIONS BY
EVENING. DURING THE EVENING HOURS...THINK THAT MOST TERMINALS SHOULD
SCATTER OUT TO MID LEVEL CLOUDS. THE EXCEPTION AGAIN WOULD BE FKL
AND DUJ...WHERE LOW LEVEL MOISTURE WOULD REMAIN MORE ENTRENCHED AND
KEEP MVFR CEILINGS IN THE FORECAST. A COLD FRONT WILL APPROACH FROM
THE WEST SATURDAY MORNING. THINK THAT ALL SITES WILL RECEIVE SOME
LIGHT PRECIPITATION...AND HAVE INDICATED THIS AT THE END OF THE TAF
CYCLE FOR SOME SITES. MANY TERMINALS MAY REMAIN VFR WITH PRECIP.
SNOW AT FKL AND DUJ WILL LIKELY RESULT IN AT LEAST MVFR RESTRICTIONS
THERE.
OUTLOOK...SATURDAY THROUGH WEDNESDAY...
POTENTIAL FOR RESTRICTIONS SHOULD CONTINUE THRU THE WEEKEND AS A
SERIES OF UPPER DISTURBANCES GENERATE SHRA/SHSN FOR MOST TERMINALS.
VFR CONDITIONS ARE THEN ANTICIPATED MONDAY AND TUESDAY UNDER HIGH
PRESSURE. A COLD FRONT IS EXPECTED TO BRING ANOTHER ROUND OF SHOWERS
AND RESTRICTIONS ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
100 PM CST FRI JAN 27 2012
.AVIATION... /18Z TAF ISSUANCE/
COLD FRONT STRETCHING FROM KINL TO KAXN TO KMML. FRONTAL
BOUNDARY EXPECTED TO MOVE THROUGH MN TAF SITES BY 00Z AND THROUGH
ALL WI AIRPORTS BY 03Z. INTENSE BAND OF SNOW PRODUCING VSBYS DOWN
TO 1/4SM OVER MUCH OF FAR EAST CENTRAL MN. IFR CIGS AND VSBYS SHOULD
BE EXPECTED AS THIS BAND PASSES YOUR LOCATION. ALL SNOW PER GFS40
290K ISENTROPIC ANAL WILL END THIS REGION BY 22Z...AND OVER KEAU BY
02-03Z. LOOK FOR SURFACE PRESSURE GRADIENT TO CONTINUE TO STRENGTHEN
OVER REGION INTO LATE THIS AFTERNOON...AND REMAIN VIRTUALLY UNCHANGED
INTO 28/18Z. GUSTINESS ASSOCIATED WITH NW FLOW WILL DECOUPLE SHORTLY
AFTER 01Z MOST LOCALES...AND RETURN BY 15Z. CLIPPER SYSTEM WILL PRODUCE
ANOTHER ROUND OF LIGHT TO VERY LIGHT SNOWFALL OVER ENTIRE REGION ON
SATURDAY...AND MAINLY DURING THE AFTN. CONVERGENCE ALOFT PER GFS40
250MB LEVEL PRETTY MUCH GUARANTEEING MAINLY MVFR TO VFR VSBYS...WITH
MVFR CIGS ASSOCIATED WITH SNOWFALL.
KMSP...MFVR...OCCASIONAL VFR CIGS WILL END AT KMSP BY 21Z ASSOCIATED
WITH INTENSE SNOW BAND JUST AHEAD OF FRONTAL BOUNDARY. WEST TO NW
FLOW WILL ENVELOP AIRPORT SITE BY 23Z...WITH GUSTINESS DECOUPLING
AFTER 02Z. CLIPPER SYSTEM WILL PRODUCE ANOTHER ROUND OF LIGHT TO
VERY LIGHT SNOWFALL OVER ENTIRE REGION ON SATURDAY...AND MAINLY
DURING THE AFTN. CONVERGENCE ALOFT PER GFS40 250MB LEVEL PRETTY MUCH
GUARANTEEING MAINLY MVFR TO VFR VSBYS...WITH MVFR CIGS ASSOCIATED
WITH SNOWFALL.
&&
.DISCUSSION... /ISSUED 427 AM CST FRI JAN 27 2012/
LIGHT SNOW EVENT STILL ON COURSE FOR TODAY. SNOW IN THE DAKOTAS
IS ONGOING WITH MOST OF THE AIRPORTS UNDERNEATH THE SNOW SHOWING
BETWEEN 1-2SM VISIBILITY. THE 27.00/06Z NAM/GFS AND 27.00Z EC NOT
DEVIATING TOO FAR FROM THURSDAY`S MODEL GUIDANCE. OVER THE PAST
24-30HR...THE MODEL SOLUTIONS HAVE SHIFTED THE BEST AXIS OF QPF
NORTH WITH TIME. LIKELY A FEW MORE LOCATIONS SEEING 2-4 INCHES
ACROSS NORTHERN PORTIONS OF MINNESOTA...ESPECIALLY GIVEN THE MORE
FAVORABLE PROFILE FOR DENDRITE SNOW GROWTH. THE MODEL GUIDANCE AND
EVEN THE RADAR THIS MORNING SHOWING TWO SEPARATE AREAS OF ENHANCED
SNOW...WITH A RELATIVE WEAKNESS OVER EASTERN SD. THESE TWO AREAS
LINE UP PRETTY WELL WITH THE 700-400MB DIFFERENTIAL VORTICITY
ADVECTION...AND SEEMS TO BE BETTER 850MB TEMPERATURE ADVECTION OFF
THE RUC IN THE VICINITY OF THESE TWO AREAS AS WELL. LOWEST SNOW
TOTALS WILL LIKELY BE IN WEST CENTRAL MN WHERE THE PRECIP SHOULD
LARGELY SPLIT THE AREA AND IT MIGHT ONLY MANAGE A TRACE OF SNOW.
THE TWO AREAS SHOULD FILL IN BY THE TIME THE WAVE MAKES IT INTO
EASTERN MN AND WESTERN WI EARLY THIS AFTERNOON...SO MOST LOCATIONS
WILL AT LEAST SEE A FEW TENTHS OF SNOW. TRIED TO TIME THE POP/WX
FORECAST WITH HOURLY GRIDS THIS MORNING AND WALK A BAND OF 60-90%
POPS ACROSS THE FORECAST AREA LATE THIS MORNING AND AFTERNOON.
PROBABLY COULD BE DONE A LITTLE MORE 80-100% POPS...BUT THE SNOW
WILL BE PRETTY LIGHT. BASED THE HOURLY TREND ON A LOT OF VARIOUS
WRF-NMM AND WRF-ARW SIMULATIONS FROM NCEP/SPC/MPX. MUCH BETTER
ISENTROPIC ADIABATIC OMEGA SLIDING ACROSS THE GRAND FORKS AND
DULUTH FORECAST AREAS. BEST CHANCE FOR 1-2" WILL BE ACROSS
PORTIONS OF CENTRAL MINNESOTA...LIKELY NEAR AND NORTH OF A LINE
FROM FERGUS FALLS...TO LITTLE FALLS...TO RICE LAKE IN WI. SNOW
LARGELY MOVES OUT OF THE FORECAST THIS EVENING.
BEYOND TODAY...THERE ARE A COUPLE OTHER MINOR SNOW EVENTS IN THE
WORKS SATURDAY THROUGH WEDNESDAY. NICE 500MB SHORT WAVE DROPS
SOUTH OUT OF SASKATCHEWAN ON SATURDAY WITH SOME SURFACE RESPONSE
AND A WEAK SURFACE TROUGH. CONVERGENCE ISN`T OVERLY STRONG...BUT
PROBABLY WORTH CHANCE POPS FOR SATURDAY AFTERNOON AND EVENING.
OVERALL THE WEEKEND WILL BE COOLER AFTER TODAY`S SYSTEM...BUT LIKE
SO MANY TIMES THIS WINTER...COLD FRONTS CAN ONLY MANAGE TO COOL AS
DOWN TO NEAR NORMAL. WARM FRONT COMES THROUGH SUNDAY NIGHT...SO
ONCE AGAIN HAVE SMALL POPS IN THE FORECAST DURING THIS TIME FRAME
DUE TO THE ISENTROPIC LIFT. EC IS A LITTLE STRONGER WITH THE UPPER
TROUGH AND SURFACE LOW ON TUESDAY COMPARED TO THE GFS...BUT IT`S
ALSO FARTHER TO THE NORTH. THE SECOND HALF OF NEXT WEEK IS QUITE
WARM IF YOU TRUST THE GFS AND THE PRONOUNCED LONG WAVE RIDGING.
THE EC HOLD THE RIDGE BACK TO THE WEST.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/CLF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1157 AM CST FRI JAN 27 2012
.UPDATE...HEAVIER SNOW BANDS HAVE DEVELOPED FARTHER NORTH THAN
ORIGINALLY THOUGHT. HAVE ADJUSTED POPS/QPF/SNOW AMOUNT
ACCORDINGLY. SNOW IS DIMINISHING ALREADY FROM BRD TO INL.
&&
.PREV DISCUSSION... /ISSUED 1127 AM CST FRI JAN 27 2012/
AVIATION...18Z TAF ISSUANCE...
AREA OF LOW PRESSURE WILL TRACK ACROSS THE SRN HALF OF THE
FORECAST AREA THIS AFTERNOON AND SPREAD SNOW SHOWERS THROUGH THE
REGION. SOME OF THESE SHOWERS COULD REDUCE VSBYS DOWN TO 1/2-1/4SM
AT TIMES...WITH TEMPORARY IFR CIGS AS WELL. THIS SYSTEM WILL BE
FAST MOVING...SO THESE CONDITIONS WILL BE SHORT-LIVED THIS
AFTERNOON. PREVAILING MVFR CIGS WITH POSSIBLE FLURRIES WILL
IMPROVE TO VFR THIS EVENING FOR MOST LOCATIONS...BUT CIGS DROP TO
MVFR AGAIN FOR HIB AND INL AFTER 06Z TONIGHT. DLH AND BRD COULD
SEE SOME LLWS THIS EVENING AND INTO THE OVERNIGHT HOURS...WITH
SPEED SHEAR BEING THE MAIN CONCERN AS SFC- 2000FT WINDS REMAIN
NEARLY UNIDIRECTIONAL. LIGHT LLWS WILL BE POSSIBLE AT ALL OTHER
TERMINALS THIS EVENING...HOWEVER CONFIDENCE IS LIMITED...THEREFORE
LEFT THE MENTION OUT OF 18Z TAFS. ANOTHER SURGE OF LOW LEVEL
MOISTURE MOVES IN FROM THE NW LATE TONIGHT...BUT CONFIDENCE IS LOW
REGARDING THE FORMATION OF LOW-END MVFR CIGS FOR THE SRN
TERMINALS...DLH...BRD AND HYR. SFC WINDS INCREASE FROM THE WNW
LATE SAT MORNING...WITH GUSTS 20-25 KNOTS.
PREV DISCUSSION... /ISSUED 934 AM CST FRI JAN 27 2012/
UPDATE...CURRENT RADAR TRENDS MATCH UP WELL WITH THE 11Z HRRR AND
HAVE ADJUSTED THE GRIDS THIS AFTERNOON TO LEAN TOWARDS ITS
SOLUTION. NO CHANGE FOR THE REST OF THIS MORNING.
PREV DISCUSSION... /ISSUED 546 AM CST FRI JAN 27 2012/
AVIATION...12Z TAF ISSUANCE...
A WEATHER SYSTEM WILL MOVE FROM EASTERN ND TO CENTRAL MN THIS
MORNING. EXPECT A PERIOD OF ABOUT 3 TO 5 HOURS OF IFR/MVFR CIGS AT
ALL TAF SITES...BEGINNING AT KBRD/KINL THIS MORNING...AND THEN AT
KHIB/KDLH/KHYR THIS AFTERNOON AS THE SYSTEM PASSES THROUGH
MN. THE PERIOD OF IFR/MVFR CIGS WILL BE ACCOMPANIED BY -SN AND
REDUCED VSBY. KINL SHOULD ESCAPE MOST OF THE SNOW...BUT
KBRD/KHIB/KDLH/KHYR WILL CLOSER TO THE FOCUS OF THE SNOWFALL AND
WILL SEE A PERIOD OF LOW END MVFR VSBYS. THIS WINDS TODAY WILL
GENERALLY BE LIGHT FROM THE WEST TO NORTHWEST...WITH SOME
INCREASING WESTERLY WINDS EARLY THIS EVENING. ONCE THE LOW MVFR
CIGS PASS...EACH TAF SITE SHOULD SEE HIGH BASED CIGS THROUGH
THE REST OF THE AFTERNOON AND INTO TONIGHT. WIND SHEAR MAY BE AN
ISSUE AT KBRD THIS EVENING DUE TO STRONG NORTHWEST WINDS
ALOFT...BUT OTHERWISE WIND SHEAR IS NOT EXPECTED TO BE AN ISSUE
FOR THE OTHER TAF SITES.
PREV DISCUSSION... /ISSUED 306 AM CST FRI JAN 27 2012/
SHORT TERM...THROUGH SATURDAY.
WE MADE SIGNIFICANT CHANGES TO THE FORECAST TODAY...NAMELY
SPREADING MUCH HIGHER POPS NORTH TO NEARLY THE INTERNATIONAL
BORDER.
SURFACE LOW PRESSURE OVER NORTH CENTRAL NORTH DAKOTA WILL MOVE ESE
TODAY...WITH 08Z SURFACE ANALYSIS SHOWING 2.5MB PRESSURE FALLS
JUST TO THE ESE OF THE LOW CENTER. THE GFS CONTINUES TO BE THE
FURTHEST SOUTH WITH THE TRACK OF THIS CLIPPER...AND THE RESULTANT
SNOW. THE 00Z ECMWF HAS SHIFTED THE LOW/PRECIP FURTHER NORTH...THE
NAM CONTINUES TO BE NORTH...AND THE HIGHER RESOLUTION 4KM WRF/3KM
HRRR SUGGEST SNOW WILL FALL FURTHER NORTH AS WELL. NAM ALSO SHOWS A
NICE FGEN SIGNATURE THAT MOVES THROUGH CASS/ITASCA COUNTIES...ESE
INTO WI. THERE WILL BE A NICE BURST OF SNOW THAT FALLS...AND 2 TO
3 INCHES IS EXPECTED IN THE MAIN AREA OF SNOW...WITH 1 TO 2 INCHES
NORTH AND SOUTH...AND EVEN LESS ALONG THE INTERNATIONAL BORDER. A
FEW HIGHER AMOUNTS WILL BE POSSIBLE AS WELL TO 4 INCHES. THE EXACT
LOCATION OF THE HEAVIER SNOW BAND AND THE SPEED OF THE SYSTEM
PRECLUDES US FROM ISSUING AN ADVISORY AT THIS TIME...BUT WE WILL
MONITOR RADAR OVER THE NEXT FEW HOURS AND ISSUE IF CONFIDENCE
INCREASES. AT THIS TIME...WE HAVE THE HIGHEST SNOW TOTALS ACROSS
NORTHERN CASS/SOUTHERN ITASCA COUNTIES INTO THE TWIN PORTS AND
ACROSS NORTHERN WISCONSIN.
SNOW SHOULD START THIS MORNING OVER OUR WESTERN CWA...REACH
THE EASTERN IRON RANGE...TWIN PORTS...INTERSTATE 35 CORRIDOR BY
EARLY AFTERNOON...THEN OUR EASTERN WISCONSIN ZONES BY MID-LATE
AFTERNOON.
THE SNOW WILL END IN OUR WEST THIS AFTERNOON...AND LINGER THROUGH
THE EVENING OVER PORTIONS OF NORTHWEST WISCONSIN.
COLDER AIR MOVES IN BEHIND THE LOW TONIGHT INTO SATURDAY. LOW
LEVEL FLOW IS TOO WESTERLY TO GET ANY SIGNIFICANT LES.
CYCLONIC UPPER LEVEL FLOW AND COLDER AIR MAY LEAD TO SOME LIGHT
SNOW SHOWERS ON SATURDAY OVER PORTIONS OF THE NORTHLAND. A
STRONGER SHORTWAVE WILL DIVE JUST SOUTHWEST OF THE CWA AND KEEP
THE HIGHER CHANCES FOR SNOW OUT OF OUR CWA. HIGHS SATURDAY WILL
RANGE FROM THE UPPER TEENS IN THE ARROWHEAD...TO THE TWENTIES
ELSEWHERE.
LONG TERM...SATURDAY NIGHT - THURSDAY...
SATURDAY NIGHT...THE NORTHLAND WILL BEGIN THE PERIOD IN COLD
NORTHWEST FLOW WITH A PASSING SHORTWAVE AND TROUGH. THERE COULD BE
LIGHT SNOW ACROSS THE SOUTHERN FA RELATED TO THE PASSING
SHORTWAVE...AND LAKE EFFECT SNOW SHOWERS ALONG PARTS OF THE SOUTH
SHORE DUE TO THE COLD NORTHWEST FLOW OVER THE LAKE. THE LATEST
MAV/MET/MEX GUIDANCE WAS INDICATING MUCH OVERNIGHT LOW
TEMPERATURES...SO LOWERED THE FORECAST.
SUNDAY...A RIDGE OF HIGH PRESSURE WILL MOVE INTO THE NORTHLAND
WHICH WILL RELAX THE NORTHWEST WINDS AND CAUSE CLEARING SKIES FROM
WEST TO EAST. THERE COULD BE LINGERING LAKE EFFECT SNOW SHOWERS
ALONG PARTS OF THE SOUTH SHORE...MOSTLY IN THE MORNING BEFORE THE
NORTHWESTERLY WINDS BECOME WESTERLY BY THE AFTERNOON.
SUNDAY NIGHT AND MONDAY...IT LOOKS LIKE A NORTHWEST TO SOUTHEAST
ORIENTATED WARM FRONT WILL MOVE INTO THE WESTERN FA OVERNIGHT AND
THE EASTERN FA MONDAY. THE FRONT COULD BRING LIGHT PCPN TO THE
FA...BUT THE MODELS DISAGREE ON THE TIMING/LOCATION/STRENGTH. BASED
ON SOUNDINGS...IT WOULD APPEAR THE PCPN WOULD INITIALLY FALL AS
LIGHT SNOW...BUT DRYING IN THE MID LEVELS BEHIND THE FRONT COULD
RESULT IN A MIXTURE OF LIGHT SNOW AND FREEZING DRIZZLE/RAIN ON
MONDAY.
MONDAY NIGHT THROUGH THURSDAY...THE MODELS SHOW A WEAK LOW PRESSURE
SYSTEM MOVING THROUGH THE UPPER MIDWEST WHICH COULD BRING LIGHT PCPN
TO THE NORTHLAND SOMETIME MONDAY NIGHT THROUGH TUESDAY NIGHT. BASED
ON SURFACE TEMPERATURES AND SOUNDINGS...IT WOULD APPEAR THERE COULD
BE A MIXTURE OF RAIN AND SNOW ACROSS THE FAR SOUTHERN FA TUESDAY. IT
THEN APPEARS WEAK HIGH PRESSURE WILL KEEP THE NORTHLAND DRY THROUGH
THE REMAINDER OF THE FORECAST.
&&
.POINT TEMPS/POPS...
DLH 30 16 22 2 / 80 10 10 10
INL 28 12 19 -6 / 40 10 20 10
BRD 30 16 24 2 / 80 10 20 10
HYR 32 14 23 2 / 80 50 10 10
ASX 33 17 24 6 / 80 50 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1127 AM CST FRI JAN 27 2012
.AVIATION...18Z TAF ISSUANCE...
AREA OF LOW PRESSURE WILL TRACK ACROSS THE SRN HALF OF THE
FORECAST AREA THIS AFTERNOON AND SPREAD SNOW SHOWERS THROUGH THE
REGION. SOME OF THESE SHOWERS COULD REDUCE VSBYS DOWN TO 1/2-1/4SM
AT TIMES...WITH TEMPORARY IFR CIGS AS WELL. THIS SYSTEM WILL BE
FAST MOVING...SO THESE CONDITIONS WILL BE SHORT-LIVED THIS
AFTERNOON. PREVAILING MVFR CIGS WITH POSSIBLE FLURRIES WILL
IMPROVE TO VFR THIS EVENING FOR MOST LOCATIONS...BUT CIGS DROP TO
MVFR AGAIN FOR HIB AND INL AFTER 06Z TONIGHT. DLH AND BRD COULD
SEE SOME LLWS THIS EVENING AND INTO THE OVERNIGHT HOURS...WITH
SPEED SHEAR BEING THE MAIN CONCERN AS SFC- 2000FT WINDS REMAIN
NEARLY UNIDIRECTIONAL. LIGHT LLWS WILL BE POSSIBLE AT ALL OTHER
TERMINALS THIS EVENING...HOWEVER CONFIDENCE IS LIMITED...THEREFORE
LEFT THE MENTION OUT OF 18Z TAFS. ANOTHER SURGE OF LOW LEVEL
MOISTURE MOVES IN FROM THE NW LATE TONIGHT...BUT CONFIDENCE IS LOW
REGARDING THE FORMATION OF LOW-END MVFR CIGS FOR THE SRN
TERMINALS...DLH...BRD AND HYR. SFC WINDS INCREASE FROM THE WNW
LATE SAT MORNING...WITH GUSTS 20-25 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 934 AM CST FRI JAN 27 2012/
UPDATE...CURRENT RADAR TRENDS MATCH UP WELL WITH THE 11Z HRRR AND
HAVE ADJUSTED THE GRIDS THIS AFTERNOON TO LEAN TOWARDS ITS
SOLUTION. NO CHANGE FOR THE REST OF THIS MORNING.
PREV DISCUSSION... /ISSUED 546 AM CST FRI JAN 27 2012/
AVIATION...12Z TAF ISSUANCE...
A WEATHER SYSTEM WILL MOVE FROM EASTERN ND TO CENTRAL MN THIS
MORNING. EXPECT A PERIOD OF ABOUT 3 TO 5 HOURS OF IFR/MVFR CIGS AT
ALL TAF SITES...BEGINNING AT KBRD/KINL THIS MORNING...AND THEN AT
KHIB/KDLH/KHYR THIS AFTERNOON AS THE SYSTEM PASSES THROUGH
MN. THE PERIOD OF IFR/MVFR CIGS WILL BE ACCOMPANIED BY -SN AND
REDUCED VSBY. KINL SHOULD ESCAPE MOST OF THE SNOW...BUT
KBRD/KHIB/KDLH/KHYR WILL CLOSER TO THE FOCUS OF THE SNOWFALL AND
WILL SEE A PERIOD OF LOW END MVFR VSBYS. THIS WINDS TODAY WILL
GENERALLY BE LIGHT FROM THE WEST TO NORTHWEST...WITH SOME
INCREASING WESTERLY WINDS EARLY THIS EVENING. ONCE THE LOW MVFR
CIGS PASS...EACH TAF SITE SHOULD SEE HIGH BASED CIGS THROUGH
THE REST OF THE AFTERNOON AND INTO TONIGHT. WIND SHEAR MAY BE AN
ISSUE AT KBRD THIS EVENING DUE TO STRONG NORTHWEST WINDS
ALOFT...BUT OTHERWISE WIND SHEAR IS NOT EXPECTED TO BE AN ISSUE
FOR THE OTHER TAF SITES.
PREV DISCUSSION... /ISSUED 306 AM CST FRI JAN 27 2012/
SHORT TERM...THROUGH SATURDAY.
WE MADE SIGNIFICANT CHANGES TO THE FORECAST TODAY...NAMELY
SPREADING MUCH HIGHER POPS NORTH TO NEARLY THE INTERNATIONAL
BORDER.
SURFACE LOW PRESSURE OVER NORTH CENTRAL NORTH DAKOTA WILL MOVE ESE
TODAY...WITH 08Z SURFACE ANALYSIS SHOWING 2.5MB PRESSURE FALLS
JUST TO THE ESE OF THE LOW CENTER. THE GFS CONTINUES TO BE THE
FURTHEST SOUTH WITH THE TRACK OF THIS CLIPPER...AND THE RESULTANT
SNOW. THE 00Z ECMWF HAS SHIFTED THE LOW/PRECIP FURTHER NORTH...THE
NAM CONTINUES TO BE NORTH...AND THE HIGHER RESOLUTION 4KM WRF/3KM
HRRR SUGGEST SNOW WILL FALL FURTHER NORTH AS WELL. NAM ALSO SHOWS A
NICE FGEN SIGNATURE THAT MOVES THROUGH CASS/ITASCA COUNTIES...ESE
INTO WI. THERE WILL BE A NICE BURST OF SNOW THAT FALLS...AND 2 TO
3 INCHES IS EXPECTED IN THE MAIN AREA OF SNOW...WITH 1 TO 2 INCHES
NORTH AND SOUTH...AND EVEN LESS ALONG THE INTERNATIONAL BORDER. A
FEW HIGHER AMOUNTS WILL BE POSSIBLE AS WELL TO 4 INCHES. THE EXACT
LOCATION OF THE HEAVIER SNOW BAND AND THE SPEED OF THE SYSTEM
PRECLUDES US FROM ISSUING AN ADVISORY AT THIS TIME...BUT WE WILL
MONITOR RADAR OVER THE NEXT FEW HOURS AND ISSUE IF CONFIDENCE
INCREASES. AT THIS TIME...WE HAVE THE HIGHEST SNOW TOTALS ACROSS
NORTHERN CASS/SOUTHERN ITASCA COUNTIES INTO THE TWIN PORTS AND
ACROSS NORTHERN WISCONSIN.
SNOW SHOULD START THIS MORNING OVER OUR WESTERN CWA...REACH
THE EASTERN IRON RANGE...TWIN PORTS...INTERSTATE 35 CORRIDOR BY
EARLY AFTERNOON...THEN OUR EASTERN WISCONSIN ZONES BY MID-LATE
AFTERNOON.
THE SNOW WILL END IN OUR WEST THIS AFTERNOON...AND LINGER THROUGH
THE EVENING OVER PORTIONS OF NORTHWEST WISCONSIN.
COLDER AIR MOVES IN BEHIND THE LOW TONIGHT INTO SATURDAY. LOW
LEVEL FLOW IS TOO WESTERLY TO GET ANY SIGNIFICANT LES.
CYCLONIC UPPER LEVEL FLOW AND COLDER AIR MAY LEAD TO SOME LIGHT
SNOW SHOWERS ON SATURDAY OVER PORTIONS OF THE NORTHLAND. A
STRONGER SHORTWAVE WILL DIVE JUST SOUTHWEST OF THE CWA AND KEEP
THE HIGHER CHANCES FOR SNOW OUT OF OUR CWA. HIGHS SATURDAY WILL
RANGE FROM THE UPPER TEENS IN THE ARROWHEAD...TO THE TWENTIES
ELSEWHERE.
LONG TERM...SATURDAY NIGHT - THURSDAY...
SATURDAY NIGHT...THE NORTHLAND WILL BEGIN THE PERIOD IN COLD
NORTHWEST FLOW WITH A PASSING SHORTWAVE AND TROUGH. THERE COULD BE
LIGHT SNOW ACROSS THE SOUTHERN FA RELATED TO THE PASSING
SHORTWAVE...AND LAKE EFFECT SNOW SHOWERS ALONG PARTS OF THE SOUTH
SHORE DUE TO THE COLD NORTHWEST FLOW OVER THE LAKE. THE LATEST
MAV/MET/MEX GUIDANCE WAS INDICATING MUCH OVERNIGHT LOW
TEMPERATURES...SO LOWERED THE FORECAST.
SUNDAY...A RIDGE OF HIGH PRESSURE WILL MOVE INTO THE NORTHLAND
WHICH WILL RELAX THE NORTHWEST WINDS AND CAUSE CLEARING SKIES FROM
WEST TO EAST. THERE COULD BE LINGERING LAKE EFFECT SNOW SHOWERS
ALONG PARTS OF THE SOUTH SHORE...MOSTLY IN THE MORNING BEFORE THE
NORTHWESTERLY WINDS BECOME WESTERLY BY THE AFTERNOON.
SUNDAY NIGHT AND MONDAY...IT LOOKS LIKE A NORTHWEST TO SOUTHEAST
ORIENTATED WARM FRONT WILL MOVE INTO THE WESTERN FA OVERNIGHT AND
THE EASTERN FA MONDAY. THE FRONT COULD BRING LIGHT PCPN TO THE
FA...BUT THE MODELS DISAGREE ON THE TIMING/LOCATION/STRENGTH. BASED
ON SOUNDINGS...IT WOULD APPEAR THE PCPN WOULD INITIALLY FALL AS
LIGHT SNOW...BUT DRYING IN THE MID LEVELS BEHIND THE FRONT COULD
RESULT IN A MIXTURE OF LIGHT SNOW AND FREEZING DRIZZLE/RAIN ON
MONDAY.
MONDAY NIGHT THROUGH THURSDAY...THE MODELS SHOW A WEAK LOW PRESSURE
SYSTEM MOVING THROUGH THE UPPER MIDWEST WHICH COULD BRING LIGHT PCPN
TO THE NORTHLAND SOMETIME MONDAY NIGHT THROUGH TUESDAY NIGHT. BASED
ON SURFACE TEMPERATURES AND SOUNDINGS...IT WOULD APPEAR THERE COULD
BE A MIXTURE OF RAIN AND SNOW ACROSS THE FAR SOUTHERN FA TUESDAY. IT
THEN APPEARS WEAK HIGH PRESSURE WILL KEEP THE NORTHLAND DRY THROUGH
THE REMAINDER OF THE FORECAST.
&&
.POINT TEMPS/POPS...
DLH 30 16 22 2 / 80 10 10 10
INL 28 12 19 -6 / 40 10 20 20
BRD 30 16 24 2 / 80 10 20 20
HYR 32 14 23 2 / 80 50 10 10
ASX 33 17 24 6 / 80 50 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GSF
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
421 PM CST FRI JAN 27 2012
.SHORT TERM...THROUGH SATURDAY AFTERNOON. PRIMARY CONCERNS ARE
TWO-FOLD...FIRST THE ONGOING WIND ADVISORY THIS AFTERNOON...AND
THEN POTENTIAL/LIKELY FIRE WEATHER ISSUES ON SATURDAY AFTERNOON.
AT 21Z...OBJECTIVE SURFACE ANALYSIS REVEALS A HEALTHY PRESSURE
GRADIENT ACROSS THE AREA...AS A 1022+MB HIGH SETTLES INTO THE
NORTHERN ROCKIES. WITH FORECAST SOUNDINGS INDICATING DEEP MIXING
TO AROUND 800MB...THE WIND ADVISORY FOR ALL BUT THE FAR EASTERN
CWA HAS WORKED OUT FAIRLY WELL...WITH SEVERAL AUTOMATED AIRPORT
SITES RECORDING SUSTAINED SPEEDS NEAR/JUST OVER 30 MPH...ALTHOUGH
PEAK GUSTS HAVE LARGELY TOPPED OUT AROUND 40 MPH...MAKING THIS A
LOW-END WIND ADVISORY OVERALL. ALOFT...AFTERNOON WATER VAPOR AND
SHORT TERM MODEL DATA CONFIRMS A BROAD SHORTWAVE TROUGH SWINGING
ACROSS THE CENTRAL CONUS. WITH PRIMARY ZONE OF SYNOPTIC SCALE LIFT
AND MID LEVEL SATURATION HAS BEEN OFF TO THE EAST FOR SEVERAL
HOURS NOW...WITH NO PRECIPITATION NOTED SO FAR THIS AFTERNOON
WITHIN THE CWA. TEMP WISE...HIGHS THIS AFTERNOON MET OR ONLY SLIGHTLY
EXCEEDED ORIGINAL FORECAST FROM THIS MORNING...RANGING FROM AROUND
40 IN THE NORTH TO UPPER 40S SOUTH.
LATE THIS AFTERNOON/TONIGHT...THE MAIN ISSUE IS THE ONGOING WIND
ADVISORY. WITH NAM FORECAST SOUNDINGS INDICATING A RAPID DIURNAL
DIMINISHMENT IN MIXING AROUND SUNSET...THE 00Z EXPIRATION TIME
LOOKS LIKE ON TARGET. THAT BEING SAID...IT WILL REMAIN RATHER
BREEZY WELL INTO THE EVENING HOURS...WITH SUSTAINED SPEEDS HOLDING
UP IN THE 15-20 MPH RANGE WITH HIGHER GUSTS. BY MIDNIGHT AND
THEREAFTER...SPEEDS SHOULD EASE DOWN INTO THE 5-15 MPH RANGE AND
TRANSITION MORE WESTERLY AS THE CENTER OF THE EXPANSIVE SURFACE
HIGH TO THE WEST SLIDES SOUTH. TURNING TO PRECIPITATION TRENDS
LATE THIS AFTERNOON/TONIGHT...INTRODUCED A MENTION OF
SCATTERED/ISOLATED FLURRIES THROUGH 03Z ACROSS MOST NEB ZONES...TO
ACCOUNT FOR UPSTREAM SNOW SHOWERS NOW EVIDENT OVER WESTERN/NORTH
CENTRAL NEBRASKA. THESE SNOW SHOWERS ARE A CLASSIC CASE OF PARTIAL
SUNSHINE ACTING UPON STEEP LOW LEVEL LAPSE RATES UNDER THE COLD
POCKET ALOFT...WITH THE LATEST SPC RUC MESOANALYSIS INDICATING 0-3KM
LAPSE RATES NOW IN THE 7.5-8.5 C/KM RANGE. SHORT TERM HIGH
RESOLUTION MODELS SUCH AS THE HRRR AND 4KM WRF-NMM HAVE HAD A GOOD
HANDLE ON THIS SNOW SHOWER/FLURRY ACTIVITY ALL DAY NOW...WITH THE
HRRR AND RADAR TRENDS CONFIRMING THAT THE WESTERN 1/2 OF THE CWA
IS MOST AT RISK FOR CATCHING SOME OF THIS FAST-MOVING ACTIVITY.
STRONGLY CONSIDERED ADDING A LOW MEASURABLE POP TO ACCOUNT FOR
POSSIBILITY THAT A FEW SPOTS MAINLY TOWARD DAWSON/VALLEY/SHERMAN
COUNTY AREA COULD MEASURE A QUICK FEW TENTHS OF SNOWFALL...BUT
WITH THE BETTER FOCUS REMAINING JUST NORTHWEST OF THE AREA...FELT
A SCATTERED FLURRY MENTION MIGHT BETTER CAPTURE THE BRIEF NATURE
OF ANY FALLING SNOW. AS LAPSE RATES LESSEN AFTER DARK AND THE
PRIMARY SHORTWAVE AXIS SLIDES EAST...ANY SNOW SHOWERS SHOULD
QUICKLY FADE AWAY...WITH LITTLE IF ANY RISK FOR THIS ACTIVITY
EXPECTED TO REMAIN BEYOND 03Z. TEMPERATURE WISE TONIGHT...THE
HEALTHY EVENING BREEZES SHOULD KEEP THINGS FROM DROPPING OFF VERY
QUICKLY...BUT EVENTUALLY EXPECT LOWS TO DROP INTO THE 17-21 RANGE
ACROSS MOST AREAS AS SKIES CLEAR...EXCEPT FOR SLIGHTLY COLDER READINGS
IN THE FAVORED SPOTS FROM VALLEY TOWARD DAWSON COUNTIES IN THE
WEST.
ON SATURDAY...THE MAIN CONCERN TURNS TO FIRE WEATHER...WHICH IS
COVERED IN THE FIRE WEATHER SECTION BELOW. ON THE LARGER SCALE
ALOFT...SLIGHT MID LEVEL HEIGHT RISES OCCUR AS BROAD RATHER HIGH
AMPLIFIED RIDGING DOMINATES THE WESTERN CONUS...WHILE OFF TO THE
EAST...THE PRIMARY SHORTWAVE PASSING THROUGH THE AREA TODAY WILL
SWING ACROSS THE SOUTHERN GREAT LAKES...WHILE AN UPSTREAM
SHORTWAVE/AREA OF CHANNELED VORTICITY SLIDES OUT OF CANADA INTO
THE EASTERN DAKOTAS. ANY PRECIPITATION ASSOCIATED WITH THIS WAVE
SHOULD REMAIN AT LEAST A FEW HUNDRED MILES OFF TO THE
NORTH/NORTHEAST OF THE CWA DURING THE AFTERNOON. IN THE LOW
LEVELS...IT WILL BE ANOTHER RATHER BREEZY LATE MORNING THROUGH
LATE AFTERNOON...BUT THIS TIME FROM THE WEST. NAM FORECAST
SOUNDINGS INDICATE IMPRESSIVE MIXING TO 800-750MB DURING THE
AFTERNOON. ALTHOUGH NOT ANTICIPATING ADVISORY LEVEL
WINDS...SUSTAINED SPEEDS OF 15-25 MPH WITH GUSTS 30-35 MPH WILL BE
COMMON. ALTHOUGH IT WILL REMAIN RATHER COOL ALOFT WITH 850MB TEMPS
ONLY RISING INTO THE -1 TO -3C RANGE DURING THE AFTERNOON...THE
DOWNSLOPE FLOW ALONG WITH NO WORSE THAN PARTLY CLOUDY SKIES SHOULD
MILK EVERY BIT OF WARMTH OUT OF THE AIRMASS AS POSSIBLE...AND
NUDGED HIGH TEMPERATURES UP SLIGHTLY FROM PREVIOUS FORECAST MOST
AREAS...WITH MOST NEB ZONES ADVERTISED BETWEEN 45-48...AND KS
ZONES 47-49. AS COVERED FURTHER IN THE FIRE WEATHER SECTION
BELOW...DEWPOINTS WERE LOWERED SEVERAL DEGREES FROM PREVIOUS
FORECAST.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THE MAJORITY OF THE
LONG TERM PERIOD WILL FEATURE WEST/NORTHWESTERLY FLOW ALOFT WITH
SEVERAL FAST MOVING WAVES RIPPLING THROUGH THE UPPER FLOW. THE
MEDIUM RANGE MODELS GENERALLY AGREE THAT THE BULK OF THE ENERGY
ASSOCIATED WITH THE WAVES NEVER REALLY TAKES DIRECT AIM AT THE
FORECAST AREA...AND WITH DRY AIR IN THE LOW LEVELS...PRECIPITATION
WILL BE HARD TO GENERATE. NOT TO SAY THERE MAY NOT BE A SMALL
CHANCE OF RAIN OR SNOW AT SOME POINT...BUT WITHOUT ANY DECENT
CHANCES OF PRECIPITATION SHOWN BY THE DETERMINISTIC RUNS...AND WITH
GEFS POPS SO LOW...WILL KEEP IT DRY THROUGH THE PERIOD.
TEMPERATURES THROUGH THE PERIOD SHOULD STAY ON THE WARM SIDE OF
NORMAL. IN FACT...MUCH OF NEXT WEEK SHOULD SEE HIGHS NEARLY 10 TO
15 DEGREES ABOVE SEASONAL AVERAGES. THE WARMEST DAY APPEARS TO BE
MONDAY WITH H85 TEMPERATURES NEAR 10 CELSIUS AND SOME MODEL
SOLUTIONS SUGGESTING HIGHS IN THE LOWER 60S. HAVE NOT GONE QUITE
THAT WARM IN THE GRIDS YET...BUT DO HAVE TEMPERATURES SOLIDLY IN THE
MID 50S TO NEAR 60. THERE SHOULD BE A COOL DOWN TOWARDS THE END OF
NEXT WEEK AS A COLD FRONT MOVES THROUGH THE REGION.
&&
.FIRE WEATHER...A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THE
ENTIRE CWA FROM 18Z-00Z SATURDAY AFTERNOON...AND AN UPGRADE TO A
RED FLAG WARNING IS VERY POSSIBLE FOR AT LEAST WESTERN PORTIONS OF
THE WATCH AREA LATER TONIGHT. WITH DEEP MIXING NEAR/IN EXCESS OF
800MB EXPECTED...AND NEARLY DUE WESTERLY LOW LEVEL WINDS...THIS IS
A CLASSIC SET UP FOR A PRONOUNCED MIX-OUT OF DAYTIME DEW POINTS.
DESPITE SURFACE TEMPERATURES ONLY TOPPING OUT IN THE 40S...THE
ANTICIPATION OF DEWPOINTS FALLING INTO THE SINGLE DIGITS MOST
AREAS YIELDS A LARGE AREA OF AFTERNOON RELATIVE HUMIDITY VALUES
FALLING BETWEEN 15-23 PERCENT...ESPECIALLY FOR LOCATIONS SOUTHWEST
OF A LINE FROM ORD TO SUPERIOR...INCLUDING NORTH CENTRAL KANSAS.
THE LATEST ECMWF/GFS DETERMINISTIC SOLUTIONS EVEN SUGGEST THAT
DEWPOINTS COULD DROP BELOW ZERO ACROSS PARTS OF THE DISTRICT...AND
ALTHOUGH DIDN/T BUY THIS FULLY YET...ITS NOT OUT OF THE QUESTION
IN THIS WESTERLY WIND REGIME. AT ANY RATE...EASTERN PORTIONS OF
THE WATCH ARE OF LOWEST CONFIDENCE TO REACH RED FLAG
WARNING...WITH HIGHEST CONFIDENCE IN THE SOUTHWEST. THE WIND
CRITERIA OF 20 MPH SUSTAINED/GUSTS TO 25 MPH ARE NOT EXPECTED TO
BE A PROBLEM...SO EVERYTHING WILL HINGE ON THE COMBINATION OF
RISING TEMPERATURES/FALLING DEWPOINTS.
&&
.PREV DISCUSSION... /ISSUED 1139 AM CST FRI JAN 27 2012/
AVIATION...18Z KGRI TAF. VFR CEILING AND UNRESTRICTED VISIBILITY
FORECAST THROUGH THE PERIOD. HOWEVER...NORTH-NORTHWEST WINDS WILL
BE RATHER STRONG THIS AFTERNOON...WITH SEVERAL HOURS OF PEAK GUST
POTENTIAL TO AROUND 36KT BEFORE SUBSIDING THIS EVENING AND TURNING
MORE WESTERLY. WINDS WILL AGAIN INCREASE MID-LATE SATURDAY
MORNING FROM THE WEST...BUT WILL NOT BE QUITE AS STRONG AS THIS
AFTERNOON. AS FOR CLOUDS TRENDS...KEPT THINGS VFR...BUT THERE IS A
4-5 HOUR WINDOW THIS AFTERNOON FOR A BROKEN/OVERCAST CEILING IN
LOW-VFR RANGE AROUND 3500 FT AGL WHICH IS COVERED IN A TEMPO GROUP.
THE FINAL 18 HOURS OF THE PERIOD WILL FEATURE VERY LITTLE CLOUD
COVER...AND ONLY OF THE MID-HIGH VARIETY AT THAT. FINALLY...IT IS
NOT OUT OF THE QUESTION THAT A BRIEF PASSING SNOW SHOWER WILL
AFFECT THE AREA LATE THIS AFTERNOON INTO THIS EVENING...BUT WITH
THE BETTER CHANCES FOR THIS FOCUSING JUST OFF TO THE NORTH AND/OR
WEST...WILL OMIT THIS LOW CONFIDENCE SCENARIO FROM THE TAF FOR
NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NEZ039>041-046>049-
060>064-072>077-082>087.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039>041-046>048-
060>063-072>076-082>086.
KS...FIRE WEATHER WATCH SATURDAY AFTERNOON FOR KSZ005>007-017>019.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR KSZ005>007-017>019.
&&
$$
SHORT TERM/AVIATION/FIRE WEATHER...PFANNKUCH
LONG TERM...CK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1150 AM CST FRI JAN 27 2012
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE EXPECTED THRU THE TAF PD. SFC COLD FRONT JUST
MOVING THRU KOFK AT 18Z WILL CONTINUE TO PROGRESS RAPIDLY THRU
KOMA AND KLNK BY 20Z TURNING WINDS TO THE NORTHWEST WITH GUSTS
NEAR 30KTS. THERE IS A LOWER CLOUD DECK ASSOCIATED WITH THE
FRONTAL BOUNDARY THAT IS AROUND 3K FT AGL. WL NEED TO WATCH THIS
CLOSELY IN CASE IT FLUCTUATES LOWER THAN 3K FT AS IT APPROACHES
KLNK AND KOMA. WINDS WILL BEGIN TO DIMINISH BY 03Z AND BECOME MORE
SOUTHWEST BY MORNING.
KERN
&&
.PREV DISCUSSION... /ISSUED 752 AM CST FRI JAN 27 2012/
PREV DISCUSSION... /ISSUED 417 AM CST FRI JAN 27 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE HAS BEEN ON PRECIPITATION
AMOUNTS/TYPE...MAINLY THIS MORNING...BUT APPARENTLY WITH MINOR
ACCUMULATIONS. AFTER THAT...WINDS THIS AFTERNOON AND THEN
TEMPERATURES ON MONDAY MAIN HAVE BEEN MAIN FOCUS.
MODEST SHORT WAVE ENERGY DROPPING SE TOWARD NORTHERN NEBRASKA THIS
MORNING WILL PROVIDE A SHOT OF STRONG LIFT TO FORECAST
AREA...ESPECIALLY NORTHERN ZONES. IT APPEARS LIFT WAS MOSTLY FROM
WARM ADVECTION EARLY AS ISENTROPIC UPGLIDE WAS STRONG IN 290-295
K LAYER. 06Z NAM LINGERED THIS LIFT LONGER INTO THIS AFTERNOON
COMPARED TO 00Z GFS...BUT NAM WAS MORE PROGRESSIVE WITH QPF FIELDS
COMPARED TO ITS 06Z RUC COUNTERPART. ALSO BASED ON TELCO/SURFACE
REPORTS THROUGH 09Z...QPF AMOUNTS FROM 06Z NAM APPEARED WAY TOO
HIGH. SO THAT MODEL APPEARED A LITTLE SUSPECT AND THUS LEANED
CLOSER TO GFS. SINCE MEASURABLE PRECIPITATION THROUGH 09Z HAD BEEN
HARD TO COME BY...LOWERED/DROPPED PRECIP MENTION EARLY THIS
MORNING SOUTHERN ZONES WITH SPRINKLES MENTIONED IN 15Z-18Z PD
AS SURFACE TEMPERATURES CLIMB ABOVE FREEZING. WILL COUNT ON LIFT
BEING STRONG ENOUGH TO COOL WARM LAYER ALOFT DOWN NORTHERN ZONES
SO THAT MAIN PRECIP TYPE EARLY WILL BE SNOW TRANSITIONING TO
SPRINKLES/FLURRIES AS BOUNDARY LAYER TEMPERATURES WARM WITH MIXING
LATER THIS MORNING. THAT LEFT A SMALL TRANSITION AREA ALONG PLATTE
RIVER WHERE NAM/GFS SUGGESTED A PERIOD OF FREEZING RAIN
POSSIBLE...ALTHOUGH THAT WILL BE CHANGED TO FREEZING SPRINKLES IN
LEGACY ZFP PRODUCT. TO FURTHER COMPLICATED MATTERS... LATEST RUC
SOUNDINGS KEPT ALL BUT FAR NW ZONES DRY INTO THIS AFTERNOON. AFTER
TROUGH PASSES...INCREASING NORTHWEST SURFACE WINDS COULD APPROACH
WIND ADVISORY CRITERIA W THROUGH NRN ZONES...BUT SPATIAL COVERAGE
AND LENGTH OF TIME WAS TOO UNCERTAIN TO ISSUE WIND ADVISORY WITH
THIS PACKAGE.
MADE LITTLE CHANGES TO TONIGHT THROUGH SUNDAY PERIOD. DECENT
MIXING AND WEAK WARM ADVECTION ON SATURDAY COULD PROVIDE A LITTLE
WARMER TEMPERATURES COMPARED TO TODAY. THEN SECONDARY PUSH OF
COLDER AIR SATURDAY NIGHT/EARLY SUNDAY FOLLOWED BY POSSIBLY MORE
CLOUDS/LESS MIXING LATER IN THE DAY COULD BRING A LITTLE COOLER
READINGS TO MOST AREAS ON SUNDAY. MAIN CHANGE IN TEMPERATURE
FORECAST WAS MADE TO THE MONDAY PERIOD WHERE HIGHS WERE RAISED BY
A CATEGORY OR SO. THERE WAS DECENT AGREEMENT BETWEEN 00Z GFS/ECMWF
IN WARMER H85 AIR ALREADY OVERSPREADING AREA BY 12Z MONDAY WITH
SUNSHINE...SW WINDS AND EVEN A BIT MORE WARM ADVECTION IN THE
AFTERNOON. PAST EVENTS SIMILAR TO THIS HAS PROVIDED 50S OVER SNOW
FREE AREAS. WITH DECENT CONSISTENCY IN MODEL RUNS...HIGHS OUTSIDE
OF EXPECTED SOME SNOW COVERED NORTHERN ZONES WERE RAISED INTO
50S...HIGHEST FAR S AND WEST CENTRAL.
AFTER THAT A SERIES OF FAST MOVING AND HARD-TO-TIME SYSTEMS BUT
OVERALL ABOVE NORMAL TEMPERATURES. FINE TUNING PROBABLY BEST LEFT
TO CLOSER TO ACTUAL TIME AND NO CHANGES WERE MADE TO A BLEND OF
MODEL/PREVIOUS FORECAST.
CHERMOK
AVIATION...
06Z TAFS FOR KOFK...KLNK AND KOMA.
DETERIORATING CONDITIONS ARE EXPECTED OVERNIGHT THROUGH 18Z AS A
STORM SYSTEM BRINGS SNOW TO NORTHEAST NEBRASKA...AND A RAIN SNOW
MIX TO KLNK AND KOMA. MID LEVEL CIGS WILL LOWER TO MVFR AT KOFK BY
10Z WITH OCCASIONAL IFR TO LIFR CIGS/VSBYS IN SNOW THROUGH 16Z.
MVFR CIGS WILL BE THE RULE AFTER 10Z AT KLNK AND KOMA WITH RAIN
AND SNOW LIKELY THROUGH 18Z. BRIEF PERIODS OF IFR VSBYS/CIGS MAY
OCCUR AT KOMA THROUGH THEN. A STRONG COLD FRONT WILL BRING AN END
TO THE PRECIPITATION BY ABOUT 18Z...BUT NORTHWEST WINDS OF 20 TO
30KTS AND BROKEN MVFR CIGS WILL FOLLOW. SKIES SHOULD CLEAR AND
WINDS DIE DOWN TOWARD 15KTS BY SHORTLY AFTER 00Z.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1139 AM CST FRI JAN 27 2012
.UPDATE...FOR THE MOST PART...FORECAST FOR TODAY REMAINS ON TRACK.
DRY AIR IN THE LOW LEVELS KEPT LEGITIMATE MEASURABLE PRECIPITATION
AT BAY THIS MORNING...WITH ONLY A FEW SNOW GRAINS/LIGHT SLEET
REPORTED IN SOME NORTHERN AREAS. FOR THIS AFTERNOON...PULLED
MEASURABLE SLIGHT CHANCE POP...BUT HAVE A SLIGHT CHANCE OF
FLURRIES/SPRINKLES GOING AFTER 20Z WITH CONTINUED SIGNAL FROM
SHORT TERM MODELS SUCH AS HRRR THAT STEEPENING LOW LEVEL LAPSE
RATES ACROSS WESTERN/NORTH CENTRAL NEB WILL EVENTUALLY SPARK SOME
ISOLATED/SCATTERED SNOW SHOWERS. ALTHOUGH MAIN FOCUS FOR THIS
ACTIVITY SHOULD REMAIN NORTH AND/OR WEST OF THE CWA...CERTAINLY
CANNOT RULE OUT SOME OF THIS ROAMING INTO THE AREA. THIS ACTIVITY
MAY EXTEND INTO THE EVENING HOURS AS WELL...AND MAY ADDRESS THIS
IN AFTERNOON UPDATE. AS FOR WIND ADVISORY...SEEMS TO BE ON TRACK
AND WILL LET RIDE AS IS. HOWEVER...A LOOK AT 12Z NAM FORECAST
SOUNDINGS INDICATES THAT THIS WILL LIKELY BE A MARGINAL
ADVISORY...THANKS TO WINDS AT THE TOP OF THE MIXED LAYER AROUND
800MB ONLY AVERAGING AROUND 40KT. AS A RESULT...ONLY EXPECTING
SUSTAINED SPEEDS AVERAGING AROUND 30 MPH...WITH PEAK GUSTS
GENERALLY 40-45 MPH. FOR TEMPS THIS AFTERNOON...TWEAKED 1-2
DEGREES UP IN A FEW AREAS...AS MANY AREAS ARE BRIEFLY SPIKING UP
AS INITIAL STRONG WINDS/INCREASED MIXING HITS...BUT FOR THE MOST
PART EXPECT NEAR-STEADY TEMPS MOST AREAS THIS AFTERNOON...WITH
HIGHS LOW 40S NORTH TO UPPER 40S SOUTH.
&&
.AVIATION...18Z KGRI TAF. VFR CEILING AND UNRESTRICTED VISIBILITY
FORECAST THROUGH THE PERIOD. HOWEVER...NORTH-NORTHWEST WINDS WILL
BE RATHER STRONG THIS AFTERNOON...WITH SEVERAL HOURS OF PEAK GUST
POTENTIAL TO AROUND 36KT BEFORE SUBSIDING THIS EVENING AND TURNING
MORE WESTERLY. WINDS WILL AGAIN INCREASE MID-LATE SATURDAY
MORNING FROM THE WEST...BUT WILL NOT BE QUITE AS STRONG AS THIS
AFTERNOON. AS FOR CLOUDS TRENDS...KEPT THINGS VFR...BUT THERE IS A
4-5 HOUR WINDOW THIS AFTERNOON FOR A BROKEN/OVERCAST CEILING IN
LOW-VFR RANGE AROUND 3500 FT AGL WHICH IS COVERED IN A TEMPO GROUP.
THE FINAL 18 HOURS OF THE PERIOD WILL FEATURE VERY LITTLE CLOUD
COVER...AND ONLY OF THE MID-HIGH VARIETY AT THAT. FINALLY...IT IS
NOT OUT OF THE QUESTION THAT A BRIEF PASSING SNOW SHOWER WILL
AFFECT THE AREA LATE THIS AFTERNOON INTO THIS EVENING...BUT WITH
THE BETTER CHANCES FOR THIS FOCUSING JUST OFF TO THE NORTH AND/OR
WEST...WILL OMIT THIS LOW CONFIDENCE SCENARIO FROM THE TAF FOR
NOW.
&&
.PREV DISCUSSION... /ISSUED 514 AM CST FRI JAN 27 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT. SOME PRECIPITATION TRYING
TO DEVELOP MAINLY IN THE NORTHERN CWA AS AN OCCLUDING FRONT MOVES
THROUGH. DEW POINT DEPRESSIONS ARE SO LARGE THAT PRECIPITATION
STRUGGLES TO REACH THE SURFACE. CUT BACK ON CHANCES OF PRECIPITATION
BECAUSE OF THIS. FREEZING RAIN LOOKS UNLIKELY AS TEMPERATURES HAVE
BUMPED UP THIS MORNING AT THE SURFACE. WILL BE EVEN MORE DIFFICULT
FOR PRECIPITATION TO MIX DOWN THE FARTHER SOUTH ONE GOES. WIND
ADVISORY IS STILL IN EFFECT FOR LATE MORNING/AFTERNOON WITH WINDS
ALOFT HAVING NO PROBLEM REACHING THE SURFACE WITH INCREASED LAPSE
RATES STEEPENING. THERE COULD BE SOME LIGHT SPRINKLE ACTIVITY...OR
EVEN FLURRY ACTIVITY IF IT OCCURS LATE ENOUGH IN THE AFTERNOON...AS
STEEP LAPSE RATES COMBINE WITH A MID-LEVEL TROUGH AXIS SWINGING
THROUGH IN THE AFTERNOON...SO I HAVE INCLUDED THIS FOR THE AFTERNOON
FOR THIS FORECAST.
TEMPERATURES WILL MODERATE INTO NEXT WEEK AS BROAD RIDGING OCCURS IN
THE WEST AND TROUGH IN THE EAST...WITH THE POLAR VORTEX FAR TO THE
NORTH. THIS TRANSLATES TO MILD AND DRY WEATHER FOR US INTO MONDAY.
LONG TERM...MONDAY THROUGH THURSDAY. MAIN FORECAST CONCERNS WILL BE
TEMPERATURES.
THE MAIN FEATURE DURING THE PERIOD IS A GENERAL NORTHWEST FLOW
ACROSS THE AREA. THERE ARE A FEW UPPER LEVEL WAVES THAT MOVE THROUGH
THE AREA. MODELS HAVE SOME DIFFERENCES IN THE TIMING OF THESE WAVES
AS THEM MOVE THROUGH THE AREA. DESPITE THE TIMING DIFFERENCES ALL
REMAIN DRY THROUGH THE PERIOD. TEMPERATURES THEN BECOME THE MAIN
CONCERN. MONDAY WILL LIKELY BE THE WARMEST DAY AHEAD OF A COLD FRONT
THAT MOVES THROUGH. THE TEMPERATURES BEHIND THE FRONT ARE COOLER BUT
ARE STILL ABOVE SEASONAL NORMALS.
LONG TERM...MONDAY THROUGH THURSDAY. MAIN FORECAST CONCERNS WILL BE
TEMPERATURES.
THE MAIN FEATURE DURING THE PERIOD IS A GENERAL NORTHWEST FLOW
ACROSS THE AREA. THERE ARE A FEW UPPER LEVEL WAVES THAT MOVE THROUGH
THE AREA. MODELS HAVE SOME DIFFERENCES IN THE TIMING OF THESE WAVES
AS THEM MOVE THROUGH THE AREA. DESPITE THE TIMING DIFFERENCES ALL
REMAIN DRY THROUGH THE PERIOD. TEMPERATURES THEN BECOME THE MAIN
CONCERN. MONDAY WILL LIKELY BE THE WARMEST DAY AHEAD OF A COLD FRONT
THAT MOVES THROUGH. THE TEMPERATURES BEHIND THE FRONT ARE COOLER BUT
ARE STILL ABOVE SEASONAL NORMALS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039>041-046>048-
060>063-072>076-082>086.
KS...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR KSZ005>007-017>019.
&&
$$
UPDATE/AVIATION...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
307 PM EST FRI JAN 27 2012
.SYNOPSIS...
DRIER AIR WILL MOVE INTO THE EASTERN CAROLINAS TONIGHT AS HIGH
PRESSURE BUILDS OVERHEAD EARLY SATURDAY. A DRY COLD FRONT WILL
PUSH THROUGH FROM THE WEST SATURDAY NIGHT...FOLLOWED BY CHILLY
TEMPERATURES ON SUNDAY AND MONDAY AS A NEW HIGH MOVES TOWARD THE
CAROLINAS. A WARMING TREND IS EXPECTED MID-WEEK...AND THE NEXT
FRONT WILL BRING A CHANCE OF RAIN THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...DRY AIR WILL CONTINUE TO MAKE ITS WAY IN THIS
AFTERNOON IN GUSTY WESTERLY WINDS. WINDS WILL REMAIN GUSTY AS THEY
CONTINUE TO SHIFT AROUND TO THE W-NW THROUGH LATE THIS AFTERNOON.
LATEST NAM SHOWING SHORTWAVE LIFTING OFF TO THE NORTHEAST WITH MORE
OF A ZONAL FLOW DEVELOPING BEHIND IT THROUGH OVERNIGHT. INITIALLY
WILL SEE DEEPER NORTHWEST FLOW WITH COOLER AND DRIER AIR MAKING ITS
WAY IN BUT BY MORNING WILL SEE FAIRLY NEUTRAL TEMP ADVECTION. 850
TEMPS ACTUALLY DROP THROUGH THIS EVENING 5 OR 6C BEFORE LEVELING OFF
TONIGHT. MAX PCP WATER RIGHT ALONG THE COAST NEAR AN INCH WILL
CONTINUE TO FALL OFF AS DRY AIR CONTINUES TO MOVE IN. PCP WATER
VALUES WILL BE DOWN LESS THAN A HALF INCH BY MORNING. ALTHOUGH THERE
MAY BE SOME RESIDUAL MOISTURE ON THE GROUND IN AREAS WITH PCP THIS
MORNING...EXPECT ENOUGH DRYING TO OCCUR TO KEEP ANY FOG OUT OF
FORECAST.
CLEARING SKIES...LIGHTER WINDS AND SOME CAA WILL ALLOW TEMPS TO
DROP THROUGH THE NIGHT DOWN NEAR 40 OR JUST BELOW FURTHER INLAND.
DRIER AIR MAKING ITS WAY IN WILL PRODUCE A DROP IN DEWPOINT TEMPS
DOWN INTO THE MID 30S IN DIMINISHING NW TO N WINDS OVERNIGHT.
GUSTY WESTERLY WINDS WILL SHIFT TO THE NW AND DIMINISH THROUGH THIS
EVENING AS GRADIENT WEAKENS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...TRANSITORY AND VERY WEAK SURFACE HIGH ACROSS
THE EASTERN CAROLINAS SATURDAY MORNING WILL SLIDE OFFSHORE DURING
THE AFTERNOON. THIS WILL BE FOLLOWED BY AN EQUALLY WEAK SHOT OF
WARM ADVECTION IN THE GAP BETWEEN THE DEPARTING HIGH AND AN
INCOMING DRY ARCTIC COLD FRONT. THIS ARCTIC FRONT WILL SWEEP
SOUTHEAST AND ACROSS THE AREA SATURDAY EVENING...FOLLOWED BY A ~12
HOUR PERIOD OF COLD ADVECTION THAT WILL DROP 850 MB TEMPS FROM +9C
LATE SATURDAY AFTERNOON TO AROUND 0C SUNDAY MORNING. ONLY A STEADY
BREEZE SATURDAY NIGHT INTO SUNDAY MORNING WILL KEEP LOW TEMPERATURES
FROM FALLING BELOW FREEZING ALL THE WAY DOWN TO THE COAST.
PRECIPITABLE WATER WILL REMAIN 0.5 INCHES OR LESS THROUGH THE
WEEKEND. WITH VERY LITTLE IF ANY LOW-LEVEL CLOUD COVER EXPECTED
THIS GIVES US HIGH CONFIDENCE IN A DRY FORECAST THROUGH THE PERIOD.
GFS AND NAM MOS HIGHS/LOWS DON`T LOOK BAD AND WERE VERY CLOSE TO
OUR PREVIOUS FORECAST NUMBERS. THERE IS A RATHER SUBSTANTIAL
DIFFERENCE IN LOW-LEVEL TEMPERATURES ON THE RAW MODELS SUNDAY
NIGHT (NAM WARMER THAN THE GFS BY 5-7 DEGREES F WITHIN THE
300-1500 FT AGL LAYER) BUT THIS HAD LITTLE IMPACT ON MOS LOWS...
PROBABLY DUE TO LIGHTER WIND SPEEDS IN THE NAM VERSUS THE GFS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...A DRY ATMOSPHERE MONDAY AND TUESDAY THROUGH
THE COLUMN AS SUBSIDENCE ALOFT ENSUES IN WAKE OF A DEPARTING UPPER
TROUGH LIFTING NE OVER NEW ENGLAND AND CANADIAN MARITIME PROVINCES.
AT GROUND LEVEL...AN ANTICYCLONE WILL BE EDGING INTO THE FORECAST
AREA DAYBREAK MONDAY...SLIPPING OFFSHORE DURING THE DAY TUESDAY.
GLOBAL MODELS ILLUSTRATING SOLID AGREEMENT MUCH OF NEXT WEEK IN
BRINGING RETURN FLOW...INCREASING LOW-LEVEL MOISTURE...AND MILD
TEMPERATURES FOR THE SEASON BEGINNING WEDNESDAY. LOW PRESSURE
EMERGING FROM THE GULF COAST STATES SHOULD BRING AN INCREASING
CHANCE OF RAIN ACROSS OUR AREA LATE WEDNESDAY AND EVEN MORE-SO BY
THURSDAY...AS THE LOW BECOME ENERGIZED BY A NORTHERN STREAM UPPER
TROUGH DIGGING ITS WAY ACROSS THE MIDDLE MISSISSIPPI VALLEY
THURSDAY INTO FRIDAY.
WHILE MODEL DIVERGENCE INCREASES DAYS 6/7...IT DOES APPEAR THE
IDEA OF AN APPROACHING UPPER TROUGH WILL SEE FRUITION. COUPLING
THIS WITH LOW-LEVEL CONVERGENCE ASSOCIATED WITH SFC LOW PRESSURE
MOVING ACROSS THE CAROLINAS...HAS PROMPTED ELEVATING POP VALUES TO
A CHANCE OF SHOWERS THURSDAY AND FRIDAY. INDICATED DRYING FROM THE
WEST LATE IN THE PERIOD OF DAY 7...BUT OBVIOUSLY WE WILL SEE
TIMING ADJUSTMENTS OR CHANGES WITH ADDITIONAL MODEL RUNS. IF THE
GFS IS CORRECT A COOL AND DRY WEEKEND...WHEREAS IF THE ECMWF HAS
ITS SAY...WE COULD REMAIN UNSETTLED INTO NEXT WEEKEND AS THE UPPER
TROUGH HOLDS WEST OF THE AREA ACROSS THE TENNESSEE VALLEY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...COLD FRONT PUSHING TO THE COAST WITH VFR CONDITIONS AT
ALL TERMINALS. THE HRRR MODEL IS HINTING AT A SMALL BAND OF LIGHT
SHOWERS FORMING BEHIND THE MAIN MOISTURE SOURCE IN THE EARLY PORTION
OF THE AFTERNOON...BUT WITH THE RAPIDLY LOWERING DEWPOINTS...THINK
THIS IS UNLIKELY. GUSTY WEST WINDS WILL DIMINISH BY EARLY
EVENING...WITH LIGHT WINDS EXPECTED AT ALL TERMINALS THROUGH THE
NIGHTTIME HOURS. THERE WILL BE A SLIGHT CHANCE FOR FOG GIVEN THE LOW
LEVEL MOISTURE...HOWEVER THE VERTICAL CHANCE IN HUMIDITY IS NOT
FAVORABLE. SATURDAY...EXCELLENT AVIATION WEATHER WITH SCATTERED
SKIES AND GOOD VISIBILITIES. WINDS WILL BE LIGHT AND VARIABLE WITH
HIGH PRESSURE DIRECTLY OVERHEAD.
EXTENDED OUTLOOK...POTENTIAL MORNING FOG TUESDAY AND
WEDNESDAY...OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...TIGHTENED GRADIENT FLOW WILL PERSIST THROUGH
THIS AFTERNOON WITH SW WINDS AROUND 20 TO 25 KTS WITH HIGHER GUSTS.
AS NORTHERN STREAM SHORTWAVE PUSHES NEXT FRONT ACROSS THE WATERS
LATER TODAY SW-W WINDS WILL SHIFT TO A MORE NW DIRECTION AND SPIKE
UP A BIT BEFORE DIMINISHING THROUGH THE NIGHT.
AS COOLER AND DRIER AIR MAKES ITS WAY IN OVERNIGHT IT WILL PRODUCE
GREATER MIXING AND KEEP GUSTIER WINDS INITIALLY. COOLER SHELF WATERS
KEEPING A MORE STABLE ENVIRONMENT WILL NOT EXPERIENCE THE STRONGER
WIND GUSTS TAKING PLACE OVER THE WARMER GULF STREAM WATERS FURTHER
OFF SHORE. AS WINDS CONTINUE TO VEER AROUND TO THE NORTH THROUGH
MORNING...THE GRADIENT WILL RELAX AND WINDS WILL DIMINISH AS HIGH
PRESSURE MOVES IN FROM THE WEST. WINDS WILL BE DOWN TO 10 TO 15 MPH
OUT OF THE NORTH BY MORNING.
AS WINDS DIMINISH IN AN OFF SHORE FLOW...SEAS WILL DROP OFF QUITE
RAPIDLY OVERNIGHT. EXPECT SEAS UP AROUND 6 TO 8 FT IN OUTER WATERS
THIS AFTERNOON TO DECREASE BELOW 5 FT BY MIDNIGHT AND SEAS WILL BE
DOWN LESS THAN 4 FT BY MORNING.
CLEARING SKIES...LIGHTER WINDS AND SOME CAA WILL ALLOW TEMPS TO
DROP THROUGH THE NIGHT DOWN NEAR 40 OR JUST BELOW FURTHER INLAND.
DRIER AIR MAKING ITS WAY IN WILL PRODUCE A DROP IN DEWPOINT TEMPS
DOWN INTO THE MID 30S IN DIMINISHING NW TO N WINDS OVERNIGHT.
GUSTY WESTERLY WINDS WILL SHIFT TO THE NW AND DIMINISH THROUGH THIS
EVENING AS GRADIENT WEAKENS.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...VERY TRANSITORY HIGH PRESSURE WILL ZIP ACROSS
THE AREA SATURDAY MORNING WITH A PERIOD OF LIGHT AND VARIABLE
WINDS. BEHIND THE DEPARTING HIGH WINDS WILL TURN TO THE SOUTH AND
SOUTHWEST DURING THE AFTERNOON...BUT WILL NOT SUBSTANTIALLY
INCREASE IN STRENGTH UNTIL A DRY ARCTIC FRONT BLASTS ACROSS THE
WATERS AROUND MIDNIGHT SATURDAY NIGHT. STEEPER LOW-LEVEL LAPSE
RATES AND PLUNGING AIR TEMPERATURES WILL PROMOTE WIND GUSTS NEAR
OR ABOVE 25 KNOTS AT TIMES...AND WE MAY NEED A SMALL CRAFT
ADVISORY FOR THIS PERIOD IN LATER FORECASTS. STRONGER WINDS WILL
DIMINISH SUNDAY BY LATE MORNING...BUT A SECONDARY SURGE OF COLD
AIR SUNDAY NIGHT WILL AGAIN INCREASE WIND SPEEDS TO 15-20 KT. WITH
GENERALLY OFFSHORE WIND TRAJECTORIES DURING THE WEEKEND SEAS
SHOULD REMAIN BELOW 4-5 FT WITHIN 20 MILES OF SHORE.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...JUST A TAD FRISKY IN N WINDS EARLY MONDAY AS
THE LEADING EDGE OF HIGH PRESSURE BARGES INTO THE REGION. THIS
COULD RESULT IN 3-4 FOOT SEAS DAYBREAK MONDAY AND PERHAPS NEAR 5
FT AT FRYING PAN SHOALS. FOLLOWING THIS BRIEF SURGE...LOVELY
BOATING CONDITIONS ON TAP LATER MONDAY AND THROUGH TUESDAY...AS
THE HIGH PRESSURE CELL PASSES LAZILY OVER THE COASTAL CAROLINAS.
THE HIGH WILL SLIP OFFSHORE SOMETIME TUESDAY...ALLOWING WINDS TO
VEER TO A LIGHT SW DIRECTION BY TUESDAY AFTERNOON. LOWER PRESSURE
GRADUALLY ORGANIZING OUT OF THE GULF COASTS STATES WILL INTERACT
WITH HIGH PRESSURE OFFSHORE TO INSTIGATE MODERATE SW WINDS OF 10
TO 15 KNOTS ON WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...RGZ
SHORT TERM...TRA
LONG TERM...MJC
AVIATION...DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1221 PM EST FRI JAN 27 2012
.SYNOPSIS...
A COLD FRONT WILL TRACK ACROSS THE REGION TODAY. FAIR WEATHER
RETURNS BY TONIGHT THROUGH THE WEEKEND AS HIGH PRESSURE SETTLES OVER
THE CAROLINAS.
&&
.NEAR TERM /TODAY THROUGH SATURDAY/...
AS OF 915 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A PREFRONTAL TROUGH MOVING EAST
ACROSS CENTRAL NORTH CAROLINA...WITH A COLD FRONT MOVING INTO THE
FOOTHILLS OF NORTH CAROLINA TOWARD THE YADKIN RIVER. AMDAR SOUNDINGS
FROM 12Z TO 13Z IN VICINITY OF BOTH KGSO AND KRDU SHOWED A
CONDITIONALLY UNSTABLE AIR MASS WITH LAPSE RATES THROUGH 500MB NEAR
THE MOIST ADIABAT. DESPITE STRONG WINDS...NEAR 60KT IN PLACES...ON
THE KRAX AND TRDU RADARS...VERY MODEST INSTABILITY...VERY LOW IF ANY
DOWNDRAFT CAPE...AND THE TIME OF DAY RESULTED IN WIND GUSTS AT THEIR
HIGHEST ON OBSERVATIONS VIEWED TO THIS POINT AT OR JUST ABOVE 40
MPH. THE SPC MESOANALYSIS HAS STARTED TO SHOW INCREASING MIXED-LAYER
CAPE IN THE LOWEST 100MB TOWARD THE COAST...BUT IT APPEARS THE
THREAT OF ANY SEVERE WEATHER SHOULD NOW BE EAST OF CENTRAL NORTH
CAROLINA.
FOR THE REST OF THE DAY...THE CONDITIONALLY UNSTABLE AIR MASS WILL
CONTINUE UNTIL THE FRONT CLEARS DURING THE AFTERNOON. GIVEN THE
AVAILABLE LAPSE RATES AND MOISTURE...AND GOOD SYNOPTIC LIFT WITH THE
FRONT AND THE MID-LEVEL TROUGH...ALONG WITH A 120KT 300MB JET MOVING
EAST...EXPECT AT LEAST SCATTERED SHOWERS ASSOCIATED WITH THE FRONT.
NAM...RUC...AND HRRR WRF GUIDANCE ALL NOTE THIS...BUT SUBSIDENCE
BEHIND THE FRONT SHOULD RESULT IN RAPIDLY FALLING CHANCES FOR
SHOWERS BY ABOUT 21Z TOWARD INTERSTATE 95. BY 00Z...WITH GOOD 850MB
SUBSIDENCE AND PRECIPITABLE WATER VALUES APPROACHING A HALF-INCH OR
LESS...CHANCES FOR SHOWERS BY DUSK ARE BELOW SLIGHT CHANCE. STILL
THE POTENTIAL FOR WIND GUSTS FROM 30 TO 40 MPH THIS AFTERNOON BASED
ON THE BOUNDARY LAYER LAPSE RATES AND WIND FORECAST BY THE 06Z NAM
BUFR SOUNDINGS...WITH WINDS DIMINISHING QUICKLY LATE AS THE GRADIENT
SLACKENS AND NIGHTTIME APPROACHES. WILL REVISIT TEMPERATURES DURING
THE LATE MORNING BASED UPON THE LATEST TRENDS AS THE FRONT PASSES...
WITH THE CURRENT FORECAST ABOVE THE MOS GUIDANCE.
TONIGHT AND SATURDAY...CONDITIONS SHOULD BE MOSTLY CLEAR. CHILLY
TONIGHT WITH LOWS IN THE MID 30S. HIGHS SATURDAY IN THE LOWER TO MID
60S WITH HIGH PRESSURE DOMINATING.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...
THIS TIME FRAME WILL FEATURE A COUPLE UPPER LEVEL DISTURBANCES...THE
FIRST ONE MOVING ACROSS THE REGION LATE SATURDAY AND THE NEXT ONE
LATE SUNDAY. BOTH OF THESE CLIPPER SYSTEMS WILL PUSH COLD FRONTS AND
REINFORCING SHOTS OF COOLER AIR INTO THE AREA. HOWEVER...DUE TO THE
LACK OF MOISTURE WITH BOTH OF THE SYSTEMS...AM EXPECTING THE FRONTAL
PASSAGES TO BE DRY. HIGH TEMPS ON SUNDAY WILL RETURN TO NEAR
SEASONABLE VALUES...GENERALLY UPPER 40S TO LOWER 50S. OVERNIGHT LOWS
ON SATURDAY NIGHT WILL BE IN THE LOW TO MID 30S...WITH SLIGHTLY
COOLER TEMPS EXPECTED BY SUNDAY NIGHT...GENERALLY THE UPPER 20S TO
LOWER 30S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...
A WARMING TREND WILL ENSUE DURING THE LONG TERM PERIOD. MODELS ARE
IN GOOD AGREEMENT THAT ZONAL FLOW WILL ENCOMPASS MUCH OF THE CONUS
BY THE BEGINNING OF THE WORK WEEK...WHILE AT THE SURFACE...HIGH
PRESSURE WILL PROGRESS ACROSS THE SOUTHEAST AND EVENTUALLY MOVE
OFFSHORE BY THE MIDDLE OF THE WEEK. AS A RESULT...SOUTHERLY FLOW
WILL RETURN TO THE REGION BY EARLY TUESDAY. THIS IN TURN WILL ALLOW
OUR TEMPS TO MODERATE AND AFTER NEAR SEASONABLE HIGHS ON MONDAY
(UPPER 40 TO LOW 50S)...MAX TEMPS WILL RISE WELL INTO THE 60S AGAIN
BY WEDNESDAY.
OUR NEXT SYSTEM IS EXPECTED TO IMPACT THE AREA SOMETIME MID TO LATE
WEEK...HOWEVER THERE IS LITTLE RUN TO RUN CONSISTENCY...AS WELL AS
SIGNIFICANT DISCREPANCIES BETWEEN THE MODELS. THEREFORE...WILL
MAINTAIN FORECAST CONSISTENCY AND GO NO HIGHER THAN SLIGHT CHANCE
POPS FOR THE LATE WEDNESDAY/THURSDAY TIME FRAME.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1220 PM FRIDAY...
A COLD FRONT MOVING THROUGH CENTRAL NORTH CAROLINA WILL BE EAST OF
INTERSTATE 95 BY AROUND 21Z. LOCAL MVFR CONDITIONS IN SHOWERS WITH
THE FRONT WILL END AS WELL...LEAVING PRIMARY HAZARD BEHIND THE FRONT
THIS AFTERNOON WESTERLY WIND GUSTS TO AROUND 30KT. GRADIENT
DIMINISHES QUICKLY LATE THIS AFTERNOON AND TONIGHT RESULTING IN
LIGHTER WINDS...VEERING QUICKLY TO SOUTH AND SOUTHWEST AROUND
SUNRISE SATURDAY. UNDER VFR CONDITIONS SATURDAY WITH POSSIBLY SOME
CU DEVELOPING FROM ABOUT 3000FT TO 3500FT...EXPECT A FEW SOUTHWEST
WIND GUSTS TO AROUND 15KT WITH MIXING DURING THE MORNING.
BEYOND THE 18Z VALID TAF PERIOD...HIGH PROBABILITY OF VFR CONDITIONS
THROUGH THE WEEKEND...CONTINUING INTO TUESDAY. CHANCES INCREASE
FOR LATE NIGHT AND MORNING LOW CLOUDS TUESDAY NIGHT INTO WEDNESDAY.
CHANCES FOR SHOWERS START TO INCREASE AS HIGH PRESSURE MOVES AWAY
FROM CENTRAL NORTH CAROLINA JUST BEYOND THE END OF THIS OUTLOOK
PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SEC
NEAR TERM...DJF/BADGETT
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 AM CST FRI JAN 27 2012
.SHORT TERM...UPDATE
1041 AM CST FRI JAN 27 2012
A BAND OF LIGHT SNOW CONTINUES TO TRACK EAST ACROSS WESTERN TO
CENTRAL MINNESOTA AND NORTH CENTRAL IOWA THIS MORNING. THERE HAS
BEEN SOME LIGHT RAIN AND SLEET THAT HAS SHOWN UP ACROSS THIS
REGION DUE TO A WARM LAYER AROUND 925MB WHERE TEMPERATURES ARE
AROUND 1 TO 3C. THE 27.14Z RUC SHOWS THIS WARM LAYER COOLING
THROUGH THE AFTERNOON...SO IT DOES NOT APPEAR THAT WE SHOULD SEE A
MIX AROUND HERE THOUGH THE 27.14Z HRRR DOES HINT AT A MIX OCCURRING
IN THE MISSISSIPPI RIVER VALLEY FROM LA CROSSE UP TO WINONA.
SO FAR...THE LOWEST VISIBILITIES DUE TO SNOW HAVE BEEN ACROSS
CENTRAL MINNESOTA NORTHWEST OF THE TWIN CITIES WITH BASICALLY A 1
TO 2SM SNOW OCCURRING THROUGH SOUTHERN MINNESOTA AND NORTHERN IOWA.
BASED ON THESE CURRENT TRENDS AND WHAT THE HRRR AND OTHER
MESOSCALE MODELS ARE SHOWING...THIS WILL BE A QUICK SNOW WITH THE
HEAVIEST RATES LASTING JUST A FEW HOURS BEFORE TAPERING OFF. HAVE
BACKED OFF ON SNOWFALL AMOUNTS A TAD FOR THIS AFTERNOON AND
EVENING WITH THE HEAVIEST SNOW STILL FALLING ACROSS NORTH CENTRAL
WISCONSIN. HAVE GONE WITH A 1 TO 3 INCH BAND THERE WITH AROUND AN
INCH GOING ACROSS THE REST OF THE REGION. BASED ON THE 27.14Z
HRRR...THE BACK EDGE OF THE SNOW AND SURFACE COLD FRONT SHOULD BE
TO THE MISSISSIPPI RIVER AROUND 00Z AND THROUGH WESTERN WISCONSIN
BY 4Z. FOR NOW...HAVE KEPT SOME CHANCES GOING INTO THE OVERNIGHT
HOURS...BUT WE MAY HAVE TO TREND THOSE BACK SOME WITH THE
AFTERNOON FORECAST PACKAGE.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
316 AM CST FRI JAN 27 2012
THE NEXT CHANCE FOR SOME PRECIPITATION WILL COME SUNDAY NIGHT INTO
MONDAY. AN AREA OF LOW PRESSURE WILL BE QUICKLY MOVING ACROSS
SOUTHERN CANADA WITH A WARM FRONT EXPECTED TO LIFT NORTHEAST
THROUGH THE REGION. THE GFS IS SHOWING AROUND 4 UBAR/S OF
ISENTROPIC UP GLIDE ON THE 280K SURFACE AHEAD OF THE WARM FRONT.
NOT A LOT OF OTHER FORCING SO ONLY SOME LIGHT PRECIPITATION
EXPECTED AS THIS COMES THROUGH. FOR NOW HAVE CARRIED THE CHANCES
ALL THE WAY THROUGH MONDAY...BUT THE AFTERNOON COULD END UP DRY.
IF THE PRECIPITATION DOES EXTEND INTO THE AFTERNOON...SOME
PRECIPITATION TYPE CONCERNS WILL COME INTO PLAY AS A WARM NOSE
ALOFT DEVELOPS. SOME ADDITIONAL CHANCES FOR PRECIPITATION COME IN
FOR TUESDAY AND TUESDAY NIGHT...BUT CONFIDENCE IS NOT HIGH AS THE
ECMWF AND 27.00Z GEM SHOW A SURFACE LOW MOVING EAST/SOUTHEAST
ACROSS THE NORTHERN GREAT LAKES WHILE THE GFS BRINGS THE LOW OUT
OF THE SOUTHWEST TOWARD THE GREAT LAKES. FOR NOW HAVE STAYED WITH
THE MODEL CONSENSUS WHICH HAS 20 TO 30 PERCENT CHANCES.
&&
.AVIATION...THROUGH 18Z SATURDAY
1148 AM CST FRI JAN 27 2012
THE MAIN CONCERN AT THE TAF SITES IS WITH THE BAND OF SNOW
CURRENTLY IN CENTRAL MINNESOTA AND NORTHERN IOWA AND WHEN IT WILL
COME THROUGH THE TAF SITES. THE LEADING EDGE OF THE SNOW SHOULD BE
INTO RST BETWEEN 19 TO 20Z AND LSE BETWEEN 21 TO 22Z. VISIBILITIES
HAVE MAINLY BEEN IN THE 1 1/2SM TO 3SM RANGE THOUGH THERE HAVE
BEEN SOME BRIEF 1/4SM TO 3/4SM REPORTS OUT ACROSS SOUTHERN
MINNESOTA AND NORTHERN IOWA. CONFIDENCE WAS NOT HIGH ENOUGH AT
THIS POINT TO PUT THESE LOWER VISIBILITIES INTO THE TAFS FOR A
BRIEF PERIOD...SO HAVE LEFT THEM OUT AT THIS POINT. WITH A DECENT
AMOUNT OF DRY LOW LEVEL AIR IN PLACE...CEILINGS SHOULD REMAIN MVFR
THROUGH THIS EVENING UNTIL THE COLD FRONT COMES THROUGH WHEN THEY
SHOULD CLIMB TO VFR. WINDS WILL BE ANOTHER ISSUE WITH SOUTHWEST
WINDS GUSTING TO 20 TO 25KTS AT RST THIS AFTERNOON AHEAD OF THE
COLD FRONT AND THEN EVEN STRONGER GUSTS UP TO 30KTS OUT OF THE
WEST NORTHWEST EXPECTED AFTER THE FRONT PASSES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 AM CST FRI JAN 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....04
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1041 AM CST FRI JAN 27 2012
.SHORT TERM...UPDATE
1041 AM CST FRI JAN 27 2012
A BAND OF LIGHT SNOW CONTINUES TO TRACK EAST ACROSS WESTERN TO
CENTRAL MINNESOTA AND NORTH CENTRAL IOWA THIS MORNING. THERE HAS
BEEN SOME LIGHT RAIN AND SLEET THAT HAS SHOWN UP ACROSS THIS
REGION DUE TO A WARM LAYER AROUND 925MB WHERE TEMPERATURES ARE
AROUND 1 TO 3C. THE 27.14Z RUC SHOWS THIS WARM LAYER COOLING
THROUGH THE AFTERNOON...SO IT DOES NOT APPEAR THAT WE SHOULD SEE A
MIX AROUND HERE THOUGH THE 27.14Z HRRR DOES HINT AT A MIX OCCURRING
IN THE MISSISSIPPI RIVER VALLEY FROM LA CROSSE UP TO WINONA.
SO FAR...THE LOWEST VISIBILITIES DUE TO SNOW HAVE BEEN ACROSS
CENTRAL MINNESOTA NORTHWEST OF THE TWIN CITIES WITH BASICALLY A 1
TO 2SM SNOW OCCURRING THROUGH SOUTHERN MINNESOTA AND NORTHERN IOWA.
BASED ON THESE CURRENT TRENDS AND WHAT THE HRRR AND OTHER
MESOSCALE MODELS ARE SHOWING...THIS WILL BE A QUICK SNOW WITH THE
HEAVIEST RATES LASTING JUST A FEW HOURS BEFORE TAPERING OFF. HAVE
BACKED OFF ON SNOWFALL AMOUNTS A TAD FOR THIS AFTERNOON AND
EVENING WITH THE HEAVIEST SNOW STILL FALLING ACROSS NORTH CENTRAL
WISCONSIN. HAVE GONE WITH A 1 TO 3 INCH BAND THERE WITH AROUND AN
INCH GOING ACROSS THE REST OF THE REGION. BASED ON THE 27.14Z
HRRR...THE BACK EDGE OF THE SNOW AND SURFACE COLD FRONT SHOULD BE
TO THE MISSISSIPPI RIVER AROUND 00Z AND THROUGH WESTERN WISCONSIN
BY 4Z. FOR NOW...HAVE KEPT SOME CHANCES GOING INTO THE OVERNIGHT
HOURS...BUT WE MAY HAVE TO TREND THOSE BACK SOME WITH THE
AFTERNOON FORECAST PACKAGE.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
316 AM CST FRI JAN 27 2012
THE NEXT CHANCE FOR SOME PRECIPITATION WILL COME SUNDAY NIGHT INTO
MONDAY. AN AREA OF LOW PRESSURE WILL BE QUICKLY MOVING ACROSS
SOUTHERN CANADA WITH A WARM FRONT EXPECTED TO LIFT NORTHEAST
THROUGH THE REGION. THE GFS IS SHOWING AROUND 4 UBAR/S OF
ISENTROPIC UP GLIDE ON THE 280K SURFACE AHEAD OF THE WARM FRONT.
NOT A LOT OF OTHER FORCING SO ONLY SOME LIGHT PRECIPITATION
EXPECTED AS THIS COMES THROUGH. FOR NOW HAVE CARRIED THE CHANCES
ALL THE WAY THROUGH MONDAY...BUT THE AFTERNOON COULD END UP DRY.
IF THE PRECIPITATION DOES EXTEND INTO THE AFTERNOON...SOME
PRECIPITATION TYPE CONCERNS WILL COME INTO PLAY AS A WARM NOSE
ALOFT DEVELOPS. SOME ADDITIONAL CHANCES FOR PRECIPITATION COME IN
FOR TUESDAY AND TUESDAY NIGHT...BUT CONFIDENCE IS NOT HIGH AS THE
ECMWF AND 27.00Z GEM SHOW A SURFACE LOW MOVING EAST/SOUTHEAST
ACROSS THE NORTHERN GREAT LAKES WHILE THE GFS BRINGS THE LOW OUT
OF THE SOUTHWEST TOWARD THE GREAT LAKES. FOR NOW HAVE STAYED WITH
THE MODEL CONSENSUS WHICH HAS 20 TO 30 PERCENT CHANCES.
&&
.AVIATION...TODAY AND TONIGHT
536 AM CST FRI JAN 27 2012
SFC LOW/MID LEVEL SHORTWAVE ENERGY OVER THE DAKOTAS AND UPSTREAM
WILL DIG SOUTHEAST AND EAST ACROSS MN/WI TODAY/THIS EVENING. VFR
CONDITIONS WILL HOLD AT THE TAF SITES THRU THE MORNING WITH AN
INITIAL DRY LOW LEVEL AIRMASS IN PLACE. FORCING/LIFT AHEAD OF THE
LOW/SHORTWAVES IS EXPECTED TO EVENTUALLY SATURATE THE COLUMN OVER
THE AREA...WITH A BAND OF SNOW TO MOVE INTO THE TAF SITES AROUND MID
AFTERNOON AND PERSIST INTO THE EVENING. VSBYS EXPECTED TO QUICKLY
DROP TO IFR ONCE THE SNOW STARTS BUT WITH THE BULK OF THE
FORCING/LIFT ABOVE 850MB AND THE INITIAL DRY AIRMASS...MOST CIGS
LATER THIS AFTERNOON/EVENING EXPECTED TO BE MVFR BUT MAY DROP TO IFR
IN ANY AREAS OF MDT SNOW. FORCING LIFT EXIT EAST OF THE AREA BY
MIDNIGHT WITH THE SNOW DIMINISHING/ENDING. SFC COLD FRONT SWEEPS
THRU DURING THE EVENING WITH WINDS BECOMING WEST/NORTHWEST AND
INCREASING INTO THE 12-18KT RANGE WITH 25-30KT GUSTS. THESE WINDS
MAY PRODUCE SOME DRIFTING/BLOWING OF THE NEW INCH OR SO OF
SNOW...ESPECIALLY AT SITES LIKE KRST. CARRIED A BLSN SNOW MENTION AT
KRST THRU MUCH OF THE EVENING. SHOULD SEE IMPROVEMENT IN CIGS/VSBYS
AFTER 06Z. DID LEAVE CIGS MVFR LATE TONIGHT WITH AREAS
BKN-OVC015-025 SHOWING UP IN ND EARLY THIS MORNING BEHIND THE COLD
FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 AM CST FRI JAN 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....04
AVIATION.....RRS