Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/21/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1225 PM MST THU JAN 19 2012
.UPDATE...
&&
.SHORT TERM...ALL HILITES HAVE EITHER BEEN CANCELLED OR EXPIRED.
WILL STILL BE LOOKING AT POSSIBLE HIGH WINDS AGAIN IN THE
FOOTHILLS TONIGHT BUT MAY END UP BEING MORE LOCALIZED. MOISTURE
DEPTH IN THE MOUNTAINS OVER NEXT 24 HOURS LOOKS RATHER SHALLOW SO
WILL LEAN TOWARDS NO HILITES WITH JUST LIGHTER SNOW AMOUNTS. GIVEN
THE INCREASING WINDS OVER THE PASSES MAY STILL NEED AN ADVISORY.
STAY TUNED FOR AFTERNOON UPDATES.
.AVIATION...NO CHANGES PER 18Z TAF WITH AN EASTERLY COMPONENT OF
THE WINDS AT ALL LOCAL TERMINALS. BJC COULD SHOW MORE WESTERLY
TONIGHT AS NEXT MOUNTAIN WAVE DECENDS THE HILL.
&&
.PREV DISCUSSION... /ISSUED 1006 AM MST THU JAN 19 2012/
UPDATE...
SHORT TERM...HAVE ALREADY CANCELLED THE BLIZZARD WARNING FOR THE
MOUNTAINS PER OBSERVATIONS AND WEB CAMS. STILL SOME LIGHT SNOW AND
GUSTY WINDS BUT CERTAINLY NOTHING WIDESPREAD. ALSO CANCELLED THE
HIGH WIND WARNING FOR ZONES 38 AND 39 AS MOUNTAIN WAVE HAS MOVED
BACK UP THE HILL AND SURFACE GRADIENT HAS RELAXED. WIND GUSTS
GENERALLY UNDER 50 MPH. THERE IS SOME MORE POTENTIAL FOR HIGH
WINDS AGAIN TONIGHT IN THE FOOTHILLS AND WILL LOOK AT SOME MORE
DATA BEFORE MAKING A DECISION. WILL MOVE LIKELY LET THE REMAINDER
OF THE HIGH WIND WARNING EXPIRE AT NOON. THE ZONE 31 WINTER STORM
WARNING DOESN`T LOOK GOOD AT THE MOMENT WITH VERY LITTLE SNOW
ONGOING BUT THIS SHOULD CHANGE LATER TODAY AND TONIGHT. HAVE
WORDED THE WSW ACCORDINGLY WITHOUT ACTUALLY CANCELLING IT.
AVIATION...SURFACE WINDS AT LOCAL TERMINALS GENERALLY SOUTHEAST
AND WILL PLAY THE PERSISTENCE FOR MUCH OF THE DAY. BJC MAY SEE
SOME WESTERLIES TONIGHT BUT A LITTLE SURPRISED THEY DIDN`T BLOW
MUCH LAST NIGHT.
PREV DISCUSSION... /ISSUED 352 AM MST THU JAN 19 2012/
SHORT TERM...A STRONG NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER
THE CWFA TODAY AND TONIGHT. STRONG WINDS HAVE NOT BEEN AS
WIDESPREAD THIS MORNING AS THE MDLS HAD SUGGESTED. THE STRONGEST
WINDS APPEARED TO HAVE OCCUR PRIOR TO MIDNIGHT. ALTHOUGH THE JET
MAX HAS SHIFTED TO THE NORTH AND EAST...THE SHEAR APPEARS TO HAVE
LESSENED THE IMPACT OF THE MOUNTAIN WAVE SO FAR THIS MORNING. IF
WE GET ANY MORE STRONG WINDS IT WILL LIKELY OCCUR PRIOR TO 15Z
THIS MORNING. IF IT DOES NOT MATERIALIZE BY THAT TIME...THEN THE DAY
SHIFT CAN CANCEL THE HIGH WIND WARNING. THE SAME CAN BE SAID FOR
THE BLIZZARD WARNING. LGT SNOW HAS DEVELOPED IN THE MOUNTAINS
OVERNIGHT AND STRONG WINDS APPEAR TO BE IMPACTING TRAVEL NEAR THE
EISENHOWER TUNNEL. THE BLIZZARD CONDITIONS WILL BE MORE WIDESPREAD
ABOVE TIMBERLINE. THOSE WINDS ARE STILL EXPECTED TO DECREASE IN
MAGNITUDE BY THIS AFTERNOON. ADDITIONAL HIGHLIGHTS MAY BE
NECESSARY FOR ZONE 33 AND 34 THIS AFTN AND TNGT. WILL LET THE
CURRENT HIGHLIGHT RUN ITS COURSE. NOT SURE THE SNOW WILL BE ENUF
TO WARRANT A WINTER STORM WARNING VS A WINTER WEATHER ADVISORY
FOR SNOW AND BLOWING SNOW. THE MDLS APPEAR TO HIT THE MOUNTAINS
NORTH OF INTERSTATE 70 THE HARDEST. THE WINTER STORM WARNING FOR
ZONE 31 STILL LOOKS ON TRACK AND ZONE 33 WILL GET SOME DECENT
SNOWFALL AS WELL. THE BEST POTENTIAL FOR SNOW WILL BE TONIGHT AS
THE MOISTURE WEST OF THE CONTINENTAL DIVIDE DEEPENS AND THE MID
LEVEL LAPSE RATES IMPROVE. NAM12 SPATIAL CROSS-SECTIONS KEEP AN
80 KTS CROSS- MOUNTAIN COMPONENT OF 80 KTS AROUND 600 MB LATE THIS
AFTN AND TONIGHT. THE WAVE AMPLICATION OVERNIGHT APPEARS FAIRLY
LIMITED SO DO NOT ANTICIPATE HIGH WINDS IN THE FOOTHILLS AS MUCH
TONIGHT. AS FOR THE NORTHEAST PLAINS...IT WILL BE DRY WITH
TEMPERATURES IN THE MID 50S TO LOWER 60S... MILDEST NEAR THE
FOOTHILLS. OVERALL ONLY MINOR ADJUSTMENTS IN THE SHORT TERM.
LONG TERM...STRONG WESTERLY FLOW ALOFT WILL CONTINUE TO TRANSPORT
PACIFIC MOISTURE ACROSS THE WESTERN U.S. THROUGH THE WEEKEND. THE
NEXT WRINKLE IN THE FLOW ALOFT WILL MOVE ACROSS THE STATE TONIGHT
AND FRIDAY. THE MOISTURE EMBEDDED IN THE STRONG WESTERLY FLOW ALOFT
WILL PRODUCE A ROUND OF OROGRAPHIC SNOW. LAPSE RATES WILL BE AROUND
5-6 C/KM...NOT THAT GREAT BUT NOT BAD EITHER. BEST SNOW ON FRIDAY
WILL OCCUR OVER WESTERN JACKSON COUNTY WHERE LOCALLY A FOOT OF NEW
SNOW IS POSSIBLE. LESSER AMOUNTS ARE EXPECTED TO THE SOUTH OVER THE
MOUNTAINS OF GRAND AND JACKSON COUNTIES. THIS SYSTEM IS PRIMARILY AN
OROGRAPHIC SNOW PRODUCER. THE MOUNTAIN VALLEYS WILL SEE A FEW STRAY
SNOW SHOWERS OFF THE MOUNTAINS. FOR THE FRONT RANGE AND EASTERN
PLAINS...DRY AND MILD CONDITIONS WILL PREVAIL.
WILL SEE A BREAK IN THE SNOW FRIDAY NIGHT AND SATURDAY. SLIGHT
RIDGING WILL OCCUR DUE TO THE NEXT SHORT WAVE TROUGH NEARING THE
ROCKIES. THIS NEXT SYSTEM WILL MOVE ACROSS THE STATE SATURDAY
NIGHT...WITH SNOW STARTING OVER NORTH CENTRAL COLORADO LATE SATURDAY
AFTERNOON. THIS WAVE IS STRONGER THAN THURSDAY NIGHT/FRIDAY`S
SYSTEM. IN ADDITION...LAPSE RATES WILL BE 7-8 C/KM SATURDAY NIGHT.
ALL OF THIS WILL PRODUCE A PERIOD OF MODERATE TO HEAVY OROGRAPHIC
SATURDAY NIGHT. WILL LIKELY NEED WINTER WEATHER HIGHLIGHTS AS THIS
SYSTEM NEARS. WOULD EXPECT THE FAVORED OROGRAPHIC SLOPES TO PICK UP
1-2 FEET OF SNOW. MOST OF THE SNOW WILL AGAIN BE OROGRAPHICALLY
DRIVEN. THERE WILL BE A BETTER CHANCE FOR SNOW IN THE MOUNTAINS
VALLEYS DUE TO BETTER INSTABILITY. WILL NOT RULE OUT THE CHANCE OF A
FEW LIGHT SNOW SHOWERS OVER THE PLAINS EITHER. ANY PRECIPITATION
HERE WILL BE LIGHT. AFTER A MILD SATURDAY OVER NORTHEAST COLORADO
WHERE HIGHS WILL BE IN THE 50S...COOLER AIR WILL MOVE IN BEHIND THE
SYSTEM FOR SUNDAY WITH HIGHS IN THE 40S.
PROGRESSIVE WEATHER PATTER WILL CONTINUE THROUGH THE EARLY PART OF
NEXT WEEK. RIDGING ON MONDAY WILL BE FOLLOWED BY A TROUGH ON
TUESDAY. THEN ANOTHER RIDGE TO AFFECT THE AREA LATE WEDNESDAY AND
INTO THURSDAY. WILL KEEP POPS IN THE MOUNTAINS EACH DAY DUE TO THE
SOMEWHAT MOIST WESTERLY FLOW AND ALSO DUE TO TIMING UNCERTAINTIES
WITH THESE SYSTEMS. THE ENERGY WITH THE SYSTEM ON TUESDAY LOOKS LIKE
IT WILL SPLIT AND MOVE AROUND COLORADO. THIS WILL KEEP MOUNTAIN
SNOWFALL AMOUNTS ON THE LIGHTER SIDE. FOR THE PLAINS...OTHER THAN
LOW POPS FOR THE SYSTEM MONDAY NIGHT TUESDAY WILL KEEP THE FORECAST
DRY. HIGHS WILL BE NEAR NORMAL AFTER THE TROUGH PASSAGE
TUESDAY...OTHERWISE ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
NORTHEAST COLORADO.
AVIATION...WIND WILL CONTINUE TO BE AN ISSUE...ESPECIALLY AT KBJC
AND KDEN THIS MORNING. AT KDEN WILL CONTINUE WITH A WESTERLY WIND
THIS MORNING UNTIL AROUND 15Z THEN IT APPEAR TO WEAKEN AND BECOME
MORE SWLY. NONE OF THE MDLS HAVE HANDLED THE WIND PATTERN VERY
WELL THIS MORNING. I WILL BE FOLLOWING THE RUC BOUNDARY LAYER
WINDS THIS MORNING. IF THE SFC TROUGH SITS ALONG THE FRONT RANGE
THIS AFTN...THEN SOME SORT OF ELY WIND COMPONENT IS STILL
POSSIBLE. AS FOR KBJC...WINDS HAVE BEEN SLOW TO MATERIALIZE THIS
MORNING. WILL KEEP THE STRONGER GUSTS IN THE TAF UNTIL 15Z THEN
DECREASE IT THEREAFTER.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....KRIEDERMAN
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1006 AM MST THU JAN 19 2012
.UPDATE...
&&
.SHORT TERM...HAVE ALREADY CANCELLED THE BLIZZARD WARNING FOR THE
MOUNTAINS PER OBSERVATIONS AND WEB CAMS. STILL SOME LIGHT SNOW AND
GUSTY WINDS BUT CERTAINLY NOTHING WIDESPREAD. ALSO CANCELLED THE
HIGH WIND WARNING FOR ZONES 38 AND 39 AS MOUNTAIN WAVE HAS MOVED
BACK UP THE HILL AND SURFACE GRADIENT HAS RELAXED. WIND GUSTS
GENERALLY UNDER 50 MPH. THERE IS SOME MORE POTENTIAL FOR HIGH
WINDS AGAIN TONIGHT IN THE FOOTHILLS AND WILL LOOK AT SOME MORE
DATA BEFORE MAKING A DECISION. WILL MOVE LIKELY LET THE REMAINDER
OF THE HIGH WIND WARNING EXPIRE AT NOON. THE ZONE 31 WINTER STORM
WARNING DOESN`T LOOK GOOD AT THE MOMENT WITH VERY LITTLE SNOW
ONGOING BUT THIS SHOULD CHANGE LATER TODAY AND TONIGHT. HAVE
WORDED THE WSW ACCORDINGLY WITHOUT ACTUALLY CANCELLING IT.
.AVIATION...SURFACE WINDS AT LOCAL TERMINALS GENERALLY SOUTHEAST
AND WILL PLAY THE PERSISTENCE FOR MUCH OF THE DAY. BJC MAY SEE
SOME WESTERLIES TONIGHT BUT A LITTLE SURPRISED THEY DIDN`T BLOW
MUCH LAST NIGHT.
&&
.PREV DISCUSSION... /ISSUED 352 AM MST THU JAN 19 2012/
SHORT TERM...A STRONG NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER
THE CWFA TODAY AND TONIGHT. STRONG WINDS HAVE NOT BEEN AS
WIDESPREAD THIS MORNING AS THE MDLS HAD SUGGESTED. THE STRONGEST
WINDS APPEARED TO HAVE OCCUR PRIOR TO MIDNIGHT. ALTHOUGH THE JET
MAX HAS SHIFTED TO THE NORTH AND EAST...THE SHEAR APPEARS TO HAVE
LESSENED THE IMPACT OF THE MOUNTAIN WAVE SO FAR THIS MORNING. IF
WE GET ANY MORE STRONG WINDS IT WILL LIKELY OCCUR PRIOR TO 15Z
THIS MORNING. IF IT DOES NOT MATERIALIZE BY THAT TIME...THEN THE DAY
SHIFT CAN CANCEL THE HIGH WIND WARNING. THE SAME CAN BE SAID FOR
THE BLIZZARD WARNING. LGT SNOW HAS DEVELOPED IN THE MOUNTAINS
OVERNIGHT AND STRONG WINDS APPEAR TO BE IMPACTING TRAVEL NEAR THE
EISENHOWER TUNNEL. THE BLIZZARD CONDITIONS WILL BE MORE WIDESPREAD
ABOVE TIMBERLINE. THOSE WINDS ARE STILL EXPECTED TO DECREASE IN
MAGNITUDE BY THIS AFTERNOON. ADDITIONAL HIGHLIGHTS MAY BE
NECESSARY FOR ZONE 33 AND 34 THIS AFTN AND TNGT. WILL LET THE
CURRENT HIGHLIGHT RUN ITS COURSE. NOT SURE THE SNOW WILL BE ENUF
TO WARRANT A WINTER STORM WARNING VS A WINTER WEATHER ADVISORY
FOR SNOW AND BLOWING SNOW. THE MDLS APPEAR TO HIT THE MOUNTAINS
NORTH OF INTERSTATE 70 THE HARDEST. THE WINTER STORM WARNING FOR
ZONE 31 STILL LOOKS ON TRACK AND ZONE 33 WILL GET SOME DECENT
SNOWFALL AS WELL. THE BEST POTENTIAL FOR SNOW WILL BE TONIGHT AS
THE MOISTURE WEST OF THE CONTINENTAL DIVIDE DEEPENS AND THE MID
LEVEL LAPSE RATES IMPROVE. NAM12 SPATIAL CROSS-SECTIONS KEEP AN
80 KTS CROSS- MOUNTAIN COMPONENT OF 80 KTS AROUND 600 MB LATE THIS
AFTN AND TONIGHT. THE WAVE AMPLICATION OVERNIGHT APPEARS FAIRLY
LIMITED SO DO NOT ANTICIPATE HIGH WINDS IN THE FOOTHILLS AS MUCH
TONIGHT. AS FOR THE NORTHEAST PLAINS...IT WILL BE DRY WITH
TEMPERATURES IN THE MID 50S TO LOWER 60S... MILDEST NEAR THE
FOOTHILLS. OVERALL ONLY MINOR ADJUSTMENTS IN THE SHORT TERM.
LONG TERM...STRONG WESTERLY FLOW ALOFT WILL CONTINUE TO TRANSPORT
PACIFIC MOISTURE ACROSS THE WESTERN U.S. THROUGH THE WEEKEND. THE
NEXT WRINKLE IN THE FLOW ALOFT WILL MOVE ACROSS THE STATE TONIGHT
AND FRIDAY. THE MOISTURE EMBEDDED IN THE STRONG WESTERLY FLOW ALOFT
WILL PRODUCE A ROUND OF OROGRAPHIC SNOW. LAPSE RATES WILL BE AROUND
5-6 C/KM...NOT THAT GREAT BUT NOT BAD EITHER. BEST SNOW ON FRIDAY
WILL OCCUR OVER WESTERN JACKSON COUNTY WHERE LOCALLY A FOOT OF NEW
SNOW IS POSSIBLE. LESSER AMOUNTS ARE EXPECTED TO THE SOUTH OVER THE
MOUNTAINS OF GRAND AND JACKSON COUNTIES. THIS SYSTEM IS PRIMARILY AN
OROGRAPHIC SNOW PRODUCER. THE MOUNTAIN VALLEYS WILL SEE A FEW STRAY
SNOW SHOWERS OFF THE MOUNTAINS. FOR THE FRONT RANGE AND EASTERN
PLAINS...DRY AND MILD CONDITIONS WILL PREVAIL.
WILL SEE A BREAK IN THE SNOW FRIDAY NIGHT AND SATURDAY. SLIGHT
RIDGING WILL OCCUR DUE TO THE NEXT SHORT WAVE TROUGH NEARING THE
ROCKIES. THIS NEXT SYSTEM WILL MOVE ACROSS THE STATE SATURDAY
NIGHT...WITH SNOW STARTING OVER NORTH CENTRAL COLORADO LATE SATURDAY
AFTERNOON. THIS WAVE IS STRONGER THAN THURSDAY NIGHT/FRIDAY`S
SYSTEM. IN ADDITION...LAPSE RATES WILL BE 7-8 C/KM SATURDAY NIGHT.
ALL OF THIS WILL PRODUCE A PERIOD OF MODERATE TO HEAVY OROGRAPHIC
SATURDAY NIGHT. WILL LIKELY NEED WINTER WEATHER HIGHLIGHTS AS THIS
SYSTEM NEARS. WOULD EXPECT THE FAVORED OROGRAPHIC SLOPES TO PICK UP
1-2 FEET OF SNOW. MOST OF THE SNOW WILL AGAIN BE OROGRAPHICALLY
DRIVEN. THERE WILL BE A BETTER CHANCE FOR SNOW IN THE MOUNTAINS
VALLEYS DUE TO BETTER INSTABILITY. WILL NOT RULE OUT THE CHANCE OF A
FEW LIGHT SNOW SHOWERS OVER THE PLAINS EITHER. ANY PRECIPITATION
HERE WILL BE LIGHT. AFTER A MILD SATURDAY OVER NORTHEAST COLORADO
WHERE HIGHS WILL BE IN THE 50S...COOLER AIR WILL MOVE IN BEHIND THE
SYSTEM FOR SUNDAY WITH HIGHS IN THE 40S.
PROGRESSIVE WEATHER PATTER WILL CONTINUE THROUGH THE EARLY PART OF
NEXT WEEK. RIDGING ON MONDAY WILL BE FOLLOWED BY A TROUGH ON
TUESDAY. THEN ANOTHER RIDGE TO AFFECT THE AREA LATE WEDNESDAY AND
INTO THURSDAY. WILL KEEP POPS IN THE MOUNTAINS EACH DAY DUE TO THE
SOMEWHAT MOIST WESTERLY FLOW AND ALSO DUE TO TIMING UNCERTAINTIES
WITH THESE SYSTEMS. THE ENERGY WITH THE SYSTEM ON TUESDAY LOOKS LIKE
IT WILL SPLIT AND MOVE AROUND COLORADO. THIS WILL KEEP MOUNTAIN
SNOWFALL AMOUNTS ON THE LIGHTER SIDE. FOR THE PLAINS...OTHER THAN
LOW POPS FOR THE SYSTEM MONDAY NIGHT TUESDAY WILL KEEP THE FORECAST
DRY. HIGHS WILL BE NEAR NORMAL AFTER THE TROUGH PASSAGE
TUESDAY...OTHERWISE ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
NORTHEAST COLORADO.
AVIATION...WIND WILL CONTINUE TO BE AN ISSUE...ESPECIALLY AT KBJC
AND KDEN THIS MORNING. AT KDEN WILL CONTINUE WITH A WESTERLY WIND
THIS MORNING UNTIL AROUND 15Z THEN IT APPEAR TO WEAKEN AND BECOME
MORE SWLY. NONE OF THE MDLS HAVE HANDLED THE WIND PATTERN VERY
WELL THIS MORNING. I WILL BE FOLLOWING THE RUC BOUNDARY LAYER
WINDS THIS MORNING. IF THE SFC TROUGH SITS ALONG THE FRONT RANGE
THIS AFTN...THEN SOME SORT OF ELY WIND COMPONENT IS STILL
POSSIBLE. AS FOR KBJC...WINDS HAVE BEEN SLOW TO MATERIALIZE THIS
MORNING. WILL KEEP THE STRONGER GUSTS IN THE TAF UNTIL 15Z THEN
DECREASE IT THEREAFTER.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL NOON MST TODAY FOR COZ035-036.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ031.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....KRIEDERMAN
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER CO
352 AM MST THU JAN 19 2012
.SHORT TERM...A STRONG NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER
THE CWFA TODAY AND TONIGHT. STRONG WINDS HAVE NOT BEEN AS
WIDESPREAD THIS MORNING AS THE MDLS HAD SUGGESTED. THE STRONGEST
WINDS APPEARED TO HAVE OCCUR PRIOR TO MIDNIGHT. ALTHOUGH THE JET
MAX HAS SHIFTED TO THE NORTH AND EAST...THE SHEAR APPEARS TO HAVE
LESSENED THE IMPACT OF THE MOUNTAIN WAVE SO FAR THIS MORNING. IF
WE GET ANY MORE STRONG WINDS IT WILL LIKELY OCCUR PRIOR TO 15Z
THIS MORNING. IF IT DOES NOT MATERIALIZE BY THAT TIME...THEN THE DAY
SHIFT CAN CANCEL THE HIGH WIND WARNING. THE SAME CAN BE SAID FOR
THE BLIZZARD WARNING. LGT SNOW HAS DEVELOPED IN THE MOUNTAINS
OVERNIGHT AND STRONG WINDS APPEAR TO BE IMPACTING TRAVEL NEAR THE
EISENHOWER TUNNEL. THE BLIZZARD CONDITIONS WILL BE MORE WIDESPREAD
ABOVE TIMBERLINE. THOSE WINDS ARE STILL EXPECTED TO DECREASE IN
MAGNITUDE BY THIS AFTERNOON. ADDITIONAL HIGHLIGHTS MAY BE
NECESSARY FOR ZONE 33 AND 34 THIS AFTN AND TNGT. WILL LET THE
CURRENT HIGHLIGHT RUN ITS COURSE. NOT SURE THE SNOW WILL BE ENUF
TO WARRANT A WINTER STORM WARNING VS A WINTER WEATHER ADVISORY
FOR SNOW AND BLOWING SNOW. THE MDLS APPEAR TO HIT THE MOUNTAINS
NORTH OF INTERSTATE 70 THE HARDEST. THE WINTER STORM WARNING FOR
ZONE 31 STILL LOOKS ON TRACK AND ZONE 33 WILL GET SOME DECENT
SNOWFALL AS WELL. THE BEST POTENTIAL FOR SNOW WILL BE TONIGHT AS
THE MOISTURE WEST OF THE CONTINENTAL DIVIDE DEEPENS AND THE MID
LEVEL LAPSE RATES IMPROVE. NAM12 SPATIAL CROSS-SECTIONS KEEP AN
80 KTS CROSS- MOUNTAIN COMPONENT OF 80 KTS AROUND 600 MB LATE THIS
AFTN AND TONIGHT. THE WAVE AMPLICATION OVERNIGHT APPEARS FAIRLY
LIMITED SO DO NOT ANTICIPATE HIGH WINDS IN THE FOOTHILLS AS MUCH
TONIGHT. AS FOR THE NORTHEAST PLAINS...IT WILL BE DRY WITH
TEMPERATURES IN THE MID 50S TO LOWER 60S... MILDEST NEAR THE
FOOTHILLS. OVERALL ONLY MINOR ADJUSTMENTS IN THE SHORT TERM.
.LONG TERM...STRONG WESTERLY FLOW ALOFT WILL CONTINUE TO TRANSPORT
PACIFIC MOISTURE ACROSS THE WESTERN U.S. THROUGH THE WEEKEND. THE
NEXT WRINKLE IN THE FLOW ALOFT WILL MOVE ACROSS THE STATE TONIGHT
AND FRIDAY. THE MOISTURE EMBEDDED IN THE STRONG WESTERLY FLOW ALOFT
WILL PRODUCE A ROUND OF OROGRAPHIC SNOW. LAPSE RATES WILL BE AROUND
5-6 C/KM...NOT THAT GREAT BUT NOT BAD EITHER. BEST SNOW ON FRIDAY
WILL OCCUR OVER WESTERN JACKSON COUNTY WHERE LOCALLY A FOOT OF NEW
SNOW IS POSSIBLE. LESSER AMOUNTS ARE EXPECTED TO THE SOUTH OVER THE
MOUNTAINS OF GRAND AND JACKSON COUNTIES. THIS SYSTEM IS PRIMARILY AN
OROGRAPHIC SNOW PRODUCER. THE MOUNTAIN VALLEYS WILL SEE A FEW STRAY
SNOW SHOWERS OFF THE MOUNTAINS. FOR THE FRONT RANGE AND EASTERN
PLAINS...DRY AND MILD CONDITIONS WILL PREVAIL.
WILL SEE A BREAK IN THE SNOW FRIDAY NIGHT AND SATURDAY. SLIGHT
RIDGING WILL OCCUR DUE TO THE NEXT SHORT WAVE TROUGH NEARING THE
ROCKIES. THIS NEXT SYSTEM WILL MOVE ACROSS THE STATE SATURDAY
NIGHT...WITH SNOW STARTING OVER NORTH CENTRAL COLORADO LATE SATURDAY
AFTERNOON. THIS WAVE IS STRONGER THAN THURSDAY NIGHT/FRIDAY`S
SYSTEM. IN ADDITION...LAPSE RATES WILL BE 7-8 C/KM SATURDAY NIGHT.
ALL OF THIS WILL PRODUCE A PERIOD OF MODERATE TO HEAVY OROGRAPHIC
SATURDAY NIGHT. WILL LIKELY NEED WINTER WEATHER HIGHLIGHTS AS THIS
SYSTEM NEARS. WOULD EXPECT THE FAVORED OROGRAPHIC SLOPES TO PICK UP
1-2 FEET OF SNOW. MOST OF THE SNOW WILL AGAIN BE OROGRAPHICALLY
DRIVEN. THERE WILL BE A BETTER CHANCE FOR SNOW IN THE MOUNTAINS
VALLEYS DUE TO BETTER INSTABILITY. WILL NOT RULE OUT THE CHANCE OF A
FEW LIGHT SNOW SHOWERS OVER THE PLAINS EITHER. ANY PRECIPITATION
HERE WILL BE LIGHT. AFTER A MILD SATURDAY OVER NORTHEAST COLORADO
WHERE HIGHS WILL BE IN THE 50S...COOLER AIR WILL MOVE IN BEHIND THE
SYSTEM FOR SUNDAY WITH HIGHS IN THE 40S.
PROGRESSIVE WEATHER PATTER WILL CONTINUE THROUGH THE EARLY PART OF
NEXT WEEK. RIDGING ON MONDAY WILL BE FOLLOWED BY A TROUGH ON
TUESDAY. THEN ANOTHER RIDGE TO AFFECT THE AREA LATE WEDNESDAY AND
INTO THURSDAY. WILL KEEP POPS IN THE MOUNTAINS EACH DAY DUE TO THE
SOMEWHAT MOIST WESTERLY FLOW AND ALSO DUE TO TIMING UNCERTAINTIES
WITH THESE SYSTEMS. THE ENERGY WITH THE SYSTEM ON TUESDAY LOOKS LIKE
IT WILL SPLIT AND MOVE AROUND COLORADO. THIS WILL KEEP MOUNTAIN
SNOWFALL AMOUNTS ON THE LIGHTER SIDE. FOR THE PLAINS...OTHER THAN
LOW POPS FOR THE SYSTEM MONDAY NIGHT TUESDAY WILL KEEP THE FORECAST
DRY. HIGHS WILL BE NEAR NORMAL AFTER THE TROUGH PASSAGE
TUESDAY...OTHERWISE ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
NORTHEAST COLORADO.
&&
.AVIATION...WIND WILL CONTINUE TO BE AN ISSUE...ESPECIALLY AT KBJC
AND KDEN THIS MORNING. AT KDEN WILL CONTINUE WITH A WESTERLY WIND
THIS MORNING UNTIL AROUND 15Z THEN IT APPEAR TO WEAKEN AND BECOME
MORE SWLY. NONE OF THE MDLS HAVE HANDLED THE WIND PATTERN VERY
WELL THIS MORNING. I WILL BE FOLLOWING THE RUC BOUNDARY LAYER
WINDS THIS MORNING. IF THE SFC TROUGH SITS ALONG THE FRONT RANGE
THIS AFTN...THEN SOME SORT OF ELY WIND COMPONENT IS STILL
POSSIBLE. AS FOR KBJC...WINDS HAVE BEEN SLOW TO MATERIALIZE THIS
MORNING. WILL KEEP THE STRONGER GUSTS IN THE TAF UNTIL 15Z THEN
DECREASE IT THEREAFTER.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL NOON MST TODAY FOR COZ035-036-038-039.
BLIZZARD WARNING UNTIL NOON MST TODAY FOR COZ033-034.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ031.
&&
$$
SHORT TERM...COOPER
LONG TERM....MEIER
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1003 PM MST WED JAN 18 2012
.AVIATION /FOR 06Z TAF ISSUANCE/...
MODERATE TO SEVERE MECHANICAL TURBULENCE IS EXPECTED ACROSS THE
REGION FOR THE NEXT 24 HOURS...ESPECIALLY NEAR THE DIVIDE. EXPECT
IFR CONDITIONS TO DEVELOP ALONG THE NRN DIVIDE AS SNOW INCREASES
ALONG THE PARK AND GORE RANGES OVERNIGHT AND CONTINUES INTO
THURSDAY.
VFR CONDITIONS WILL PERSIST AT ALL TAF SITES. HOWEVER AREAS OF
LIGHT SNOW WILL BE IN THE VICINITY OF KASE AND KEGE. THERE IS A
SLIGHT CHANCE THAT 5SM -SN BRN025 CONDITIONS WILL OCCUR AT THESE
AIRPORTS.
&&
.PREV DISCUSSION /ISSUED 711 PM MST WED JAN 18 2012/...
UPDATE...
THE DEEPER MOISTURE PLUME REMAINS NORTH OF COLORADO BUT EXPECTED
TO SAG SOUTHWARD LATER THIS EVENING. SNOW HAS NOT STARTED OVER THE
WEST SIDE OF THE DIVIDE JUST YET...BUT MODELS INDICATE SNOW WILL
BE EXPANDING SOUTHWARD OVER THE NRN DIVIDE AND NEAR VAIL PASS
BETWEEN 8 PM AND 11 PM THIS EVENING. A LITTLE CONCERNED THAT WEST
SOUTHWEST FLOW AT MOUNTAIN TOP MAY SHELTER VAIL PASS AND SNOW MAY
BE HARD PRESS TO DEVELOP THERE. THE LATEST HRRR MODEL KEPT THE
SNOW EAST OF VAIL PASS. WILL SEE WHAT EVOLVES DURING THE NEXT 3 TO
6 HOURS.
PREV DISCUSSION /ISSUED 323 PM MST WED JAN 18 2012/...
SHORT TERM /TONIGHT THROUGH FRIDAY/...
THE PACIFIC MOISTURE TAP HAS OPENED UP...EXTENDING FROM THE PACIFIC
NORTHWEST BACK TO HAWAII AND BEYOND ON WATER VAPOR SATELLITE IMAGES.
A SERIES OF SHORTWAVE TROUGHS ACROSS THE NORTHERN PACIFIC OCEAN WILL
TAP THIS MOISTURE AS THEY MOVE INLAND ACROSS THE NORTHERN AND CENTRAL
ROCKIES IN THE DAYS AHEAD.
THE FIRST SHORTWAVE WAS MOVING ACROSS OREGON/WASHINGTON BUT WILL GET
STRETCHED AND WEAKEN BY THE TIME IT ZIPS ACROSS THE NORTH TONIGHT.
REGIONAL RADAR SHOWING PRECIP ACROSS SRN ID/NRN NV/NW UT...AND THIS
DEEPER MOISTURE IS EXPECTED TO STEADILY ADVANCE INTO NE UT/WRN CO
TONIGHT CAUSING SNOW TO INCREASE ACROSS THE NORTHERN AND CENTRAL
MTNS. THIS COUPLED WITH STRONG WINDS WILL PRODUCE HAZARDOUS WINTER
CONDITIONS IN THE ELKHEAD/PARK/GORE/FLATTOP/ELK MTNS TONIGHT INTO
THU MORNING. MAIN FORCING LOOKS TO BE WARM ADVECTION AND PERSISTENT
AND MOIST WESTERLY OROGRAPHIC FLOW SLAMMING INTO THE MTNS. MODELS
INDICATE 700 MB /ROUGHLY 10K FEET ELEVATION/ WESTERLY WINDS IN THE
40-55 KT RANGE NORTH OF I-70. LOOKS LIKE A DOWNTURN IN SNOW ACTIVITY
LATER BY THU AFTERNOON IN BETWEEN SHORTWAVES...WITH THE NEXT AND
STRONGER WAVE AFFECTING THE FORECAST AREA THU NIGHT INTO FRI. IF
CURRENT MODELS ARE CORRECT...SNOW COULD LAST LONGER INTO FRI THAN
CURRENT WINTER HIGHLIGHT SUGGEST. BUT...WITH TIMING OFTEN
PROBLEMATIC IN THESE FAST ZONAL FLOW REGIMES...WILL NOT DO ANY
ADJUSTING AT THIS TIME. THE EASTERN UINTA MTNS ARE EXPECTED TO
GENERALLY BE SHADOWED BY THE HIGHER MTNS TO THEIR WEST WITH ONLY
SOME LIGHT ACCUMULATIONS.
ADDED A BLIZZARD WARNING FOR CO ZONE 10 /GORE AND ELK MTNS/ TO
THE MIX OF WINTER HIGHLIGHTS FOR THE NORTHERN CO MTNS TONIGHT AND
THU MORNING. MOST CONCERNED ABOUT VAIL PASS AND SURROUNDING AREAS
WHERE BLOWING SNOW AND STRONG WINDS SHOULD POSE A SIGNIFICANT
DANGER TO TRAVEL OVER I-70 TONIGHT. LOWER AND MORE WESTERN VALLEY
AREAS OF ZONE 10 NOT LIKELY TO BE AS AFFECTED. THANKS FOR THE
COORDINATION WFO BOU AND PUB.
THERE IS OVERLAP OF PRODUCTS AT THIS TIME BUT EXPECT THE WIND
HIGHLIGHTS TO BE CANCELLED AS THE SNOW/BLIZZARD HIGHLIGHTS GO
INTO EFFECT THIS EVENING.
AN AREA THAT BEARS WATCHING IS THE STEAMBOAT VALLEY. NAM FORECAST
SOUNDINGS HAVE THE LOWER ATMOSPHERE BECOMING NEARLY SATURATED AND
ISOTHERMAL IN THE LOWER END OF THE FAVORABLE SNOW GROWTH REGIME FOR
A TIME TONIGHT...OFTEN FAVORABLE FOR ENHANCED SNOW PRODUCTION.
RAISED POPS TO LIKELY TONIGHT AND ADDED A COUPLE INCHES OF
ACCUMULATION FOR THE VALLEY FROM ABOUT HAYDEN EAST TO STEAMBOAT.
STEAMBOAT VALLEY COULD SEE ACCUMULATING SNOW AGAIN THU NIGHT/FRI
MORNING.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
ACTIVE PATTERN WILL CONTINUE AS THE MOIST AND ENERGETIC FLOW OVER
THE REGION PERSISTS THROUGH THE LONG TERM PERIOD. A COUPLE OF
SHORTWAVE TROUGHS WILL MOVE ACROSS THE WESTERN CONUS BEGINNING ON
SATURDAY. EACH WAVE WILL BRING A ROUND OF SNOW...ESPECIALLY FOR
THE MOUNTAINS...AS IT SWEEPS OVER EASTERN UTAH AND WESTERN
COLORADO. THE NORTH WILL GENERALLY BE FAVORED. DUE TO THE FAST
PACIFIC FLOW FEEL THAT MODEL TIMING WILL CONTINUE TO EVOLVE
SOMEWHAT...BUT IN GENERAL MODELS SHOW EXCELLENT AGREEMENT.
THE PERIOD BEGINS IN A LULL AS A FLAT SHORTWAVE RIDGE PASSES
FRIDAY NIGHT. THEN PRECIPITATION WILL SPREAD IN ON SATURDAY AS
THIS PERIOD/S FIRST TROUGH APPROACHES AND MOVES OVERHEAD SAT NIGHT.
THE PATTERN BECOMES MORE AMPLIFIED BUT STILL PROGRESSIVE AS THIS
TROUGH DIGS INTO THE CENTRAL CONUS...AND A RIDGE FOLLOWS ACROSS
THE WEST. SNOW WILL GRADUALLY WIND DOWN ON SUN/SUN NIGHT AS THE
RIDGE AXIS PASSES OVERHEAD. THE NEXT WAVE APPROACHES ON MONDAY
WITH THE TROUGH AXIS REACHING WESTERN COLORADO MONDAY EVENING.
AGAIN MODEL CONSISTENCY QUITE HIGH. AFTER THIS WAVE MODELS
INDICATE A LESS PROGRESSIVE FLOW AS HIGH PRESSURE BUILDS OFF THE
SOUTHERN CALIFORNIA COAST...AND LOW PRESSURE OVER THE GREAT LAKES
TO THE SOUTHERN PLAINS. NORTHWEST FLOW WILL DEVELOP OVER OUR AREA
AND PERSIST THROUGH THE END OF THE PERIOD. EXPECT THAT THE
NORTHERN DIVIDE AREA WILL CONTINUE TO SEE SNOW SHOWERS AT TIMES IN
THIS FAVORABLE NORTHWEST FLOW.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...HIGH WIND WARNING UNTIL NOON MST THURSDAY FOR ZONE 012.
WIND ADVISORY UNTIL NOON MST THURSDAY FOR ZONES 018-019.
WINTER STORM WARNING UNTIL 9 AM MST FRIDAY FOR ZONE 004.
BLIZZARD WARNING UNTIL NOON MST THURSDAY FOR ZONE 010.
WINTER WEATHER ADVISORY UNTIL 9 AM MST FRIDAY FOR ZONE 013.
UT...NONE.
&&
$$
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....PF
AREA FORECAST DISCUSSION
NWS ALBANY NY
442 PM EST THU JAN 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO LINGER OVER THE REGION INTO THE
AFTERNOON...THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL IMPACT OUR
REGION LATE BY THIS EVENING...BRINGING SOME LIGHT SNOW AND SNOW
SHOWERS. A MORE SIGNIFICANT STORM MAY IMPACT OUR REGION LATE FRIDAY
NIGHT THROUGH SATURDAY AS IT MOVES FROM THE TENNESSEE VALLEY ACROSS
THE MIDDLE ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1230 PM...HAD TO BACK OFF THE ARRIVAL OF CLOUDS AND ANY SNOW
PER SURFACE OBS. RADARS INDICATED THE SNOW SHOWERS WERE JUST
ENTERING BUFFALO. THE HRRR EXPERIMENTAL MODEL DOES INDICATE RETURNS
OF NEAR 20 DBZ NOT REACHING ALBANY UNTIL 00Z. PREVIOUS PACKAGE HAD
IT ARRIVING A FEW HOURS. THE AIR IS VERY DRY(AS WAS OUR 12Z RAOB)
AND WILL LIKELY CAUSE THE INITIAL SURGE OF MOISTURE TO EVAPORATE.
NO CHANGE ON HIGH TEMPERATURES BASED ON THIS 12Z RAOB WHICH WHEN
FULLY MIXING THE LOW LEVEL INVERSION GAVE ALBANY A HIGH OF 26. WE
ARE ALREADY 23...SO UPPER 20S LOOKS HERE...LOWER 30S SOUTH AND 20-25
MOST OTHER PLACES...EXCEPT TEENS FAR NORTH AND HIGHEST ELEVATION.
ALL PRECIPITATION SHOULD BE SNOW WITH THIS SYSTEM...BUT FINAL
SNOWFALL AMOUNTS STILL NOT ETCHED IN STONE. FOR NOW...LEFT CURRENT
THINKING FROM TONIGHT ALONE AS WE CONTINUE TO ACCESS ON THE NEW
INCOMING DATA.
FOR THE NEXT SEVERAL HOURS...LOOK FOR SUNSHINE TO BE FOLLOWED BY
RAPID INCREASING CLOUDS FROM THE WEST AND ANY SNOW LIKELY TO HOLD
OFF CERTAINLY FROM THE HUDSON VALLEY EAST...POSSIBLY REACHING OUR
SOUTHERN ADIRONDACKS BY 400 PM.
********PREVIOUS NEAR TERM FORECAST**************
AS OF 950 AM EST...A CLIPPER LOW CONTINUES TO QUICKLY APPROACH
FROM SOUTHEASTERN ONTARIO THIS AFTERNOON. THE HIGH CLOUDS IN
ADVANCE OF A WEAK WARM FRONT CONTINUES TO OVERSPREAD THE REGION.
THE DENSER CANOPY OF CLOUDS IS OVER WRN NY. WE RETOOLED THE CLOUD
TRENDS AND THE POP/WX TRENDS BASED ON THE LATEST NAM/HRRR. THE
WARM ADVECTION LIGHT SNOW/SNOW SHOWERS DOESN/T LOOK LIKE IT WILL
MOVE INTO MOST OF THE REGION UNTIL AFTER 23Z /6 PM/. THE BEST
CHANCE OF SOME SNOW IN THE LATE AFTERNOON IS OVER THE WRN DACKS.
WE INCREASED THE POPS TO LIKELY THERE. THE 12Z KALB SOUNDING IS
VERY DRY...AND IT WILL TAKE A LITTLE TIME TO SATURATE. THINKING
REMAINS FOR THE HIGHEST TOTALS ACROSS THE SRN DACKS...SRN
GREENS...NRN BERKS...AND PARTS OF THE MOHAWK VALLEY WITH 2-4 INCHES.
AN INCH OR TWO IS POSSIBLE FROM THE CAPITAL REGION NORTHWARD INTO THE
LAKE GEORGE REGION AND WEST INTO THE ERN CATSKILLS. AN INCH OR LESS
IS POSSIBLE IN THE MID HUDSON VALLEY...SRN TACONICS SOUTHWARD.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
A BRIEF VISIT BY HIGH PRESSURE ON FRIDAY...THEN ANOTHER FAST MOVING
SYSTEM WILL AFFECT THE REGION LATE FRIDAY NIGHT AND SATURDAY. THIS
LOW PRESSURE SYSTEM IS TRACKING FROM THE TENNESSEE VALLEY AND WILL
HAVE MORE MOISTURE TO WORK WITH. IT IS NEVERTHELESS AN OPEN WAVE
WITH NOT A LOT OF DYNAMICS. FOR ONCE...THIS SYSTEM LOOKS TO BE
PRETTY MUCH ALL SNOW ACROSS OUR REGION. THERE MIGHT BE A LITTLE
SPOTTY FREEZING DRIZZLE AT THE TAIL END OF THE STORM AS THE MODELS
INDICATE THE CLOUDS WILL LOOSE THEIR ICE AT THAT POINT.
THEREFORE WE CONTINUE OUR THINKING THAT THIS WILL NOT BE A MAJOR
STORM BUT LOOKS TO BRING ADVISORY LEVEL SNOW SOUTH OF CAPITAL
DISTRICT.
THE SNOW LOOKS TO SPREAD INTO THE REGION FROM SOUTHWEST TO NORTHEAST
PRIOR TO OR AROUND DAYBREAK ON SATURDAY AS THE SURFACE LOW TRACKS
WELL SOUTH OF THE MASON DIXON LINE. FAIRLY GOOD ISENTROPIC LIFT AND
A DECENT (BUT NOT IMPRESSIVE) FRONTOGENTIC BAND WILL PASS ACROSS OUR
SOUTHERN AREAS. THERE MIGHT BE A PRETTY SHARP CUTOFF IN THE SNOW
WELL NORTH OF THE CAPITAL DISTRICT. FOR NOW...WE HAVE CATEGORICAL
POPS SOUTH OF THE CAPITAL DISTRICT...LIKELY CAPITAL DISTRICT AND
CHANCES NORTH.
SNOW WILL LIKELY BECOME MODERATE FOR A AWHILE FROM JUST SOUTH OF
ALBANY...BUT THIS WILL BE ANOTHER FAST MOVING SYSTEM WHICH WILL HELP
PREVENT HEAVIER AMOUNTS. LIQUID TO SNOW RATIOS LOOK A LITTLE HIGHER
THAN THE CLIMATOLOGICAL 13:1...ESPECIALLY FROM ALBANY NORTHWARD.
THAT SAID...THE 18Z NAM CAME IN WITH SLIGHTLY HIGHER AMOUNTS OF QPF
AGAIN AND WOULD IMPLY ADVISORY LEVELS RIGHT UP TO THE CAPITAL
DISTRICT. FOR NOW THOUGH...WE WILL CONTINUE WITH THE PREVIOUS
THINKING OF A 2-4 INCH SNOWFALL GREATER CAPITAL REGION...MOHAWK
VALLEY...NORTHERN BERKSHIRES AND SOUTHERN VERMONT. FURTHER
SOUTH...4-6 INCHES CAN BE EXPECTED ACROSS THE CATSKILLS...MUCH OF
THE MID HUDSON VALLEY...SOUTHERN BERKSHIRES...AND LITCHFIELD COUNTY.
THE SNOW LOOKS TO WIND DOWN...AGAIN POSSIBLY ENDING AS LITTLE
FREEZING DRIZZLE DURING THE AFTERNOON ON SATURDAY. (WE DID NOT
MENTION ANY FREEZING DRIZZLE IN THE GRIDS SINCE THE CONFIDENCE OF
THIS HAPPENING WAS STILL RATHER LOW).
HIGH TEMPERATURES LOOK TO BE 25-30 MOST PLACES ON SATURDAY...20 TO
25 WELL NORTH OF ALBANY.
HIGH PRESSURE LOOKS TO BUILD BACK FROM EASTERN CANADA SATURDAY NIGHT
INTO SUNDAY. IF WE CLEAR OUT SATURDAY NIGHT AND GET A DECENT
SNOWPACK...TEMPERATURES COULD GET QUITE COLD BY SUNDAY MORNING. WE
FEEL PRETTY CONFIDENT THE SKY WILL CLEAR...AT LEAST NORTH OF ALBANY.
HOWEVER THE SNOW PACK WILL BE LESS IN THAT VICINITY.
FOR NOW...FOLLOWED A BLEND OF THE MET/MAV GUIDANCE WHICH GAVE US
COLD TEMPS UP NORTH WITH LOTS OF SINGLE NUMBERS...TEENS SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AN AREA OF HIGH PRESSURE WILL MOVE FROM JUST NORTH OF THE REGION ON
SUNDAY MORNING TO JUST EAST OF NORTHERN MAINE BY SUNDAY EVENING.
ENOUGH SUBSIDENCE WILL BE IN PLACE OVER OUR REGION TO ALLOW FOR A
DRY DAY ON SUNDAY WITH PARTLY TO MOSTLY SUNNY SKIES AND TEMPS CLOSE
TO SEASONAL AVERAGES /GENERALLY UPPER 20S TO MIDDLE 30S/.
CLOUDS WILL BEGIN TO INCREASE ON SUNDAY EVENING AS A STRONG STORM
SYSTEM DEEPENS OVER THE NORTHERN GREAT LAKES. A SOUTHERLY LOW LEVEL
JET OF 40-50 KTS AROUND 850 HPA WITH BEGIN TO TRANSPORT WARMER AIR
ALOFT INTO THE REGION. SFC TEMPS WON/T DROP OFF MUCH AT ALL. FOR
NOW...WE HAVE TEMPS BASICALLY STEADY OVERNIGHT...ALTHOUGH THE LOW
MAY WIND UP ACTUALLY BEING IN THE LATE EVENING WITH TEMPS RISING
OVERNIGHT. THE SOUTHERLY FLOW WILL ALLOW FOR SOME WEAK ISENTROPIC
LIFT AND MAY ALLOW FOR A PERIOD OF LIGHT PRECIPITATION OVERNIGHT.
WITH SFC TEMPS BELOW FREEZING IN MANY PLACES...THE PRECIP WILL BEGIN
AS A WINTRY MIX. THE LATEST 12 UTC GFS BUFR SOUNDINGS SHOW THAT A
SNOW/SLEET MIX MAY QUICKLY CHANGE TO RAIN OR FREEZING RAIN DEPENDING
ON THE BOUNDARY LAYER TEMPS. THIS FZRA MAY HANG ON FOR A FEW HOURS
EVEN INTO MONDAY MORNING /MAINLY ACROSS THE SOUTHERN GREENS OR
DACKS/ BEFORE TEMPS WARM UP ENOUGH EVERYWHERE FOR JUST PLAIN RAIN
SHOWERS. TEMPS SHOULD WARM UP WELL INTO THE 40S IN MOST PLACES AS
THE STRONG LOW LIFTS INTO SOUTHERN CANADA.
THE STORM/S COLD FRONT SHOULD PASS THROUGH THE REGION DURING THE
EVENING HOURS ON MONDAY. THIS WILL ALLOW TEMPS TO FALL DOWN
SOMEWHAT AND END THE THREAT FOR WIDESPREAD PRECIP. TEMPS WILL BE
COOLER FOR TUESDAY...BUT STILL A LITTLE ABOVE NORMAL...WITH MAX
TEMPS NEAR 40 FOR THE CAPITAL REGION. IT WILL GENERALLY BE DRY FOR
TUESDAY INTO WEDNESDAY AS WEAK HIGH PRESSURE PASSES OVER THE AREA.
TEMPS ON WED WILL CONTINUE TO BE A LITTLE ABOVE NORMAL FOR MOST
AREAS...WITH UPPER 30S IN THE CAPITAL REGION.
THE MODELS DISAGREE SOMEWHAT FOR THURSDAY. THE LATEST 12 UTC ECMWF
SHOWS A WEAK NORTHERN STREAM CLIPPER STORM MOVING ACROSS THE
AREA...WHILE THE 12 UTC GFS SHOWS A LITTLE DEEPER LOW MOVING TO THE
SOUTH OF THE REGION. IN EITHER SCENARIO...WE WOULD HAVE A CHANCE
OF SOME LIGHT SNOWFALL...SO WILL GO WITH CHC POPS FOR LIGHT
SNOW...ALTHOUGH QPF WILL DEPEND ON JUST HOW THE STORM TRACKS. WITH
THIS BEING VERY FAR OUT...IT/S BOUND TO CHANGE SEVERAL TIMES WITH
SUBSEQUENT MODEL RUNS...SO IT/S A LOW CONFIDENCE FORECAST AT THIS
TIME. FOR NOW...WITH THE EXPECTED CLOUDS/PRECIP...WILL FORECAST
TEMPS A LITTLE CLOSER TO SEASONAL NORMALS...WITH LOWER TO MIDDLE 30S
FOR MANY AREAS.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PERSIST INTO THE EVENING HOURS AT ALL OUR TAFS.
LOW PRESSURE NORTH OF THE GREAT LAKES REGION...WILL DRAG A COLD
FRONT THROUGH LATER TONIGHT. THERE MIGHT BE A BURST OF SNOW WITH
THIS FEATURE...BUT IT SHOULD NOT LAST LONG AND IFR CONDITIONS LOOK
TO BE BRIEF IF AT ALL. KGFL HAS THE BEST CHANCE OF EXPERIENCING IFR
BUT EVEN HERE FOR NOW...WE KEPT THEM (AS ALL OF THE OTHER TAFS) MVFR
AS CONFIDENCE REMAINS TOO LOW TO INCLUDE. (UNDER 50 PERCENT).
THIS LOW PRESSURE SYSTEM WILL BE QUICK MOVING...WITH ONLY VCSH
EXPECTED BY 08Z/KALB...09Z/KGFL AND 10Z/KPOU. ANY REMAIN SNOW
SHOWERS WILL BE SHORT LIVED AS SUBSIDENCE BEHIND THE COLD FRONT
ACCOMPANYING THE SYSTEM WILL MOVE OVER THE AREA MID TO LATE
FRIDAY MORNING. THIS SUBSIDENCE WILL ALSO HELP DECREASE CLOUD
COVER.
WINDS WILL BE OUT OF THE SOUTH AT 3-8 KTS...WITH KALB
EXPERIENCING SOME GUSTS TO 18 KTS. OVERNIGHT...WINDS WILL SHIFT
BEHIND THE COLD FRONT FROM SOUTH TO W SOMETIME BETWEEN 08Z AND 10Z
THEN INCREASE IN THE MID TO LATE MORNING AND THROUGH THE DAY.
OUTLOOK...
FRI...VFR...NO SIG WX.
SAT...SUB-VFR...CIG. SNOW..ESPECIALLY FROM ALBANY SOUTH.
SUN...VFR...NO SIG WX.
MON-TUE...SUB-VFR...CIG. CHC -RA/-SN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH THE
WEEKEND AS ANY PRECIPITATION WHICH FALLS WILL BE IN THE FORM OF SNOW.
A CLIPPER TYPE SYSTEM WHICH IS EXPECTED TO BRIEF BURST OF SNOW TO
MANY LOCATIONS TONIGHT. QPF AMOUNTS WILL BE LESS THAN A QUARTER OF
AN INCH AND SINCE IT WILL BE ALL SNOW NO IMPACT ON ANY WATERSHEDS.
A MORE SIGNIFICANT STORM IS EXPECTED TO TRACK FROM THE TENNESSEE
VALLEY TOWARD THE MIDDLE ATLANTIC COAST BRINGING A GENERALLY LIGHT
TO MODERATE SNOWFALL TO THE REGION LATE FRIDAY NIGHT INTO SATURDAY
WITH THE POTENTIAL FOR HEAVIER SNOW ACROSS THE HIGHER TERRAIN SOUTH
AND EAST OF CAPITAL DISTRICT. SINCE AGAIN IT LOOKS TO BE ALL
SNOW...NO IMPACT ON ANY OUR WATERSHEDS.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE END OF THE WEEK AS COLD AIR WILL BE IN PLACE ACROSS
THE REGION.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...HWJIV
SHORT TERM...HWJIV
LONG TERM...FRUGIS
AVIATION...KGM
HYDROLOGY...HWJIV/GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1243 PM EST THU JAN 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO LINGER OVER THE REGION INTO THE
AFTERNOON...THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL IMPACT OUR
REGION LATE BY THIS EVENING...BRINGING SOME LIGHT SNOW AND SNOW
SHOWERS. A MORE SIGNIFICANT STORM MAY IMPACT OUR REGION LATE FRIDAY
NIGHT THROUGH SATURDAY AS IT MOVES FROM THE TENNESSEE VALLEY ACROSS
THE MIDDLE ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM...HAD TO BACK OFF THE ARRIVAL OF CLOUDS AND ANY SNOW
PER SURFACE OBS. RADARS INDICATED THE SNOW SHOWERS WERE JUST
ENTERING BUFFALO. THE HRRR EXPERIMENTAL MODEL DOES INDICATE RETURNS
OF NEAR 20 DBZ NOT REACHING ALBANY UNTIL 00Z. PREVIOUS PACKAGE HAD
IT ARRIVING A FEW HOURS. THE AIR IS VERY DRY(AS WAS OUR 12Z RAOB)
AND WILL LIKELY CAUSE THE INITIAL SURGE OF MOISTURE TO EVAPORATE.
NO CHANGE ON HIGH TEMPERATURES BASED ON THIS 12Z RAOB WHICH WHEN
FULLY MIXING THE LOW LEVEL INVERSION GAVE ALBANY A HIGH OF 26. WE
ARE ALREADY 23...SO UPPER 20S LOOKS HERE...LOWER 30S SOUTH AND 20-25
MOST OTHER PLACES...EXCEPT TEENS FAR NORTH AND HIGHEST ELEVATION.
ALL PRECIPITATION SHOULD BE SNOW WITH THIS SYSTEM...BUT FINAL
SNOWFALL AMOUNTS STILL NOT ETCHED IN STONE. FOR NOW...LEFT CURRENT
THINKING FROM TONIGHT ALONE AS WE CONTINUE TO ACCESS ON THE NEW
INCOMING DATA.
FOR THE NEXT SEVERAL HOURS...LOOK FOR SUNSHINE TO BE FOLLOWED BY
RAPID INCREASING CLOUDS FROM THE WEST AND ANY SNOW LIKELY TO HOLD
OFF CERTAINLY FROM THE HUDSON VALLEY EAST...POSSIBLY REACHING OUR
SOUTHERN ADIRONDACKS BY 400 PM.
********PREVIOUS NEAR TERM FORECAST**************
AS OF 950 AM EST...A CLIPPER LOW CONTINUES TO QUICKLY APPROACH
FROM SOUTHEASTERN ONTARIO THIS AFTERNOON. THE HIGH CLOUDS IN
ADVANCE OF A WEAK WARM FRONT CONTINUES TO OVERSPREAD THE REGION.
THE DENSER CANOPY OF CLOUDS IS OVER WRN NY. WE RETOOLED THE CLOUD
TRENDS AND THE POP/WX TRENDS BASED ON THE LATEST NAM/HRRR. THE
WARM ADVECTION LIGHT SNOW/SNOW SHOWERS DOESN/T LOOK LIKE IT WILL
MOVE INTO MOST OF THE REGION UNTIL AFTER 23Z /6 PM/. THE BEST
CHANCE OF SOME SNOW IN THE LATE AFTERNOON IS OVER THE WRN DACKS.
WE INCREASED THE POPS TO LIKELY THERE. THE 12Z KALB SOUNDING IS
VERY DRY...AND IT WILL TAKE A LITTLE TIME TO SATURATE. THINKING
REMAINS FOR THE HIGHEST TOTALS ACROSS THE SRN DACKS...SRN
GREENS...NRN BERKS...AND PARTS OF THE MOHAWK VALLEY WITH 2-4 INCHES.
AN INCH OR TWO IS POSSIBLE FROM THE CAPITAL REGION NORTHWARD INTO THE
LAKE GEORGE REGION AND WEST INTO THE ERN CATSKILLS. AN INCH OR LESS
IS POSSIBLE IN THE MID HUDSON VALLEY...SRN TACONICS SOUTHWARD.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A BRIEF VISIT BY HIGH PRESSURE ON FRIDAY...THEN ANOTHER FAST MOVING
SYSTEM WILL AFFECT THE REGION LATE FRIDAY NIGHT AND SATURDAY. THIS
LOW PRESSURE SYSTEM WILL BE BETTER ORGANIZED AND ALSO TRACK TO THE
SOUTH OF THE REGION...MOVING OFF THE MID ATLANTIC COAST ON SATURDAY.
HEAVIER SNOW POSSIBLE WITH THIS SYSTEM...BUT NO MAJOR STORM IS
EXPECTED. PRELIMINARY FORECAST SNOWFALL AMOUNTS INDICATE ONE TO FOUR
INCHES OF SNOW POSSIBLE ACROSS THE NORTHERN HALF OF THE FORECAST
AREA...AND 3 TO 7 INCHES OVER THE SOUTH. HOWEVER...WOULD NOT TAKE
MUCH OF A SOUTHWARD SHIFT IN THE TRACK OF THIS LOW PRESSURE SYSTEM
TO REDUCE THESE SNOWFALL AMOUNTS SIGNIFICANTLY.
SOME MODEL DIFFERENCES EXIST IN TERMS OF TIMING OF THIS EVENT.
GFS/ECMWF HAVE SIMILAR TIMING WITH THE SNOW STARTING AROUND OR
SHORTLY AFTER MIDNIGHT FRIDAY NIGHT...AND ENDING BY EARLY AFTERNOON
SATURDAY. THEN NAM STARTS THE SNOW AROUND SUNRISE ON SATURDAY...AND
LINGERS IT INTO EARLY SATURDAY EVENING. FOR NOW HAVE FORECAST CLOSER
TO THE FASTER GFS/ECMWF SOLUTIONS. DESPITE THE TIMING DIFFERENCES...
MODEL FORECASTS OF SNOWFALL AMOUNTS ARE SIMILAR.
STILL COLD THIS PERIOD...HIGHS FRIDAY WILL BE IN THE UPPER TEENS TO
LOWER 30S...LOWS FRIDAY NIGHT IN THE SINGLE NUMBERS AND TEENS...
HIGHS SATURDAY IN THE 20S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
FAST BROAD CYCLONIC FLOW WITH EMBEDDED UPPER IMPULSES WILL CONTINUE
TO AFFECT OUR REGION THROUGH THE PERIOD...WITH A RELATIVELY STRONG
SYSTEM TO AFFECT THE REGION BETWEEN SUNDAY NIGHT AND MONDAY
EVENING. FIRST...SATURDAY NIGHT AND SUNDAY...HIGH PRESSURE WILL
CONTROL THE WEATHER WITH LOWS IN THE TEENS...SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS SUNDAY WITH INCREASING CLOUDS IN THE LOW
TO MID 30S...WITH UPPER 20S IN HIGHER ELEVATIONS.
STRONG UPPER ENERGY APPROACHES SUNDAY NIGHT...WITH INCREASING WARM
ADVECTION AND ISENTROPIC LIFT...AND AREAS OF PRECIPITATION WILL
SPREAD ACROSS THE REGION. LOTS OF UNCERTAINTY ON THE TIMING OF WARM
AIR ALOFT BUT THE GENERAL CONSENSUS FOR SNOW CHANGING TO MIXED
PRECIPITATION VERY LATE SUNDAY NIGHT AND THROUGH MONDAY MORNING.
MIXED PRECIPITATION WOULD INCLUDE SOME POSSIBILITIES FOR FREEZING
RAIN. BY MONDAY AFTERNOON...MOST AREAS OUTSIDE OF THE SOUTHERN
ADIRONDACKS SHOULD SEE A COLD RAIN...WITH SOME MIXED PRECIPITATION
POSSIBLY ALL DAY IN THE SOUTHERN ADIRONDACKS. LOWS SUNDAY NIGHT IN
THE MID 20S TO NEAR 30...SOME TEENS IN THE SOUTHERN ADIRONDACKS.
HIGHS MONDAY IN THE UPPER 30S TO MID 40S...FEW COOLER AREAS IN THE
SOUTHERN ADIRONDACKS.
CONSIDERABLE SPREAD IN GUIDANCE/ENSEMBLES BEYOND MONDAY NIGHT.
SYSTEM MOVES OUT SOME TIME WITHIN THE TIME WINDOW BETWEEN MONDAY
AFTERNOON AND TUESDAY MORNING...WITH COLD ADVECTION BEGINNING.
PRECIPITATION TRANSITIONS TO SNOW SHOWER ACTIVITY. LOWS MONDAY
NIGHT IN THE 20S TO LOWER 30S. DRYING AND CLEARING EITHER LATE
MONDAY NIGHT OR TUESDAY...AND REMAINING DRY THROUGH WEDNESDAY. HIGHS
TUESDAY IN THE 30S TO LOWER 40S. SOME STRONGER COLD ADVECTION
WEDNESDAY WITH HIGHS IN THE MID 30S TO NEAR 40...SOME 20S IN HIGHER
ELEVATIONS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PERSIST THROUGH AT LEAST THE NEXT 6 HOURS AS
HIGH PRESSURE SLIDES EASTWARD TOWARD THE CANADIAN MARITIMES. LOW
PRESSURE NORTH OF THE GREAT LAKES REGION...WITH A COLD FRONT
DRAPING JUST WEST OF THE OHIO RIVER VALLEY...HAS ALREADY STARTED
TO SPREAD MID AND HIGH LEVEL CLOUDS INTO EASTERN NY. CLOUDS WILL
CONTINUE TO INCREASE AND LOWER THROUGHOUT THE DAY...WITH MVFR
CIGS ARRIVING AFTER 00Z/FRIDAY...WHICH WILL BE ACCOMPANIED BY
SNOW. KGFL AND KALB COULD SEE A BRIEF PERIOD OF IFR DURING
SNOWFALL BETWEEN 00Z AND 06Z...BUT CONFIDENCE IS LOW ON TIMING OF
BRIEF IFR CONDITIONS. KGFL AND KALB CAN EXPECT 1 TO 2 INCHES OF
SNOWFALL BY EARLY FRIDAY MORNING. KPOU WILL LIKELY SEE LESS THAN
ONE INCH.
THIS LOW PRESSURE SYSTEM WILL BE QUICK MOVING...WITH ONLY VCSH
EXPECTED BY 08Z/KALB...09Z/KGFL AND 10Z/KPOU. ANY REMAIN SNOW
SHOWERS WILL BE SHORT LIVED AS SUBSIDENCE BEHIND THE COLD FRONT
ACCOMPANYING THE SYSTEM WILL MOVE OVER THE AREA MID TO LATE
FRIDAY MORNING. THIS SUBSIDENCE WILL ALSO HELP DECREASE CLOUD
COVER.
WINDS WILL BE OUT OF THE SOUTH AT 3-8 KTS...WITH KALB
EXPERIENCING SOME GUSTS TO 18 KTS. OVERNIGHT...WINDS WILL SHIFT
BEHIND THE COLD FRONT FROM SOUTH TO SW-W SOMETIME BETWEEN 08Z AND
10Z THEN INCREASE IN THE MID TO LATE MORNING AND THROUGH THE DAY.
OUTLOOK...
FRI...VFR...NO SIG WX.
SAT...MVFR/IFR...SNOW LIKELY.
SUN...VFR...NO SIG WX.
MON-TUE...VFR/MVFR/IFR...CHC -RA/-SN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH THE
WEEKEND AS ANY PRECIPITATION WHICH FALLS WILL BE IN THE FORM OF SNOW.
COLD AND DRY WEATHER WILL PREVAIL THROUGH MOST OF TODAY...FOLLOWED
BY A CLIPPER TYPE SYSTEM WHICH IS EXPECTED TO BRING LIGHT SNOW TO
THE REGION LATE TODAY AND TONIGHT. A MORE SIGNIFICANT STORM IS
EXPECTED TO TRACK FROM THE TENNESSEE VALLEY TOWARD THE MIDDLE
ATLANTIC COAST BRINGING A GENERALLY LIGHT TO MODERATE SNOWFALL TO
THE REGION LATE FRIDAY NIGHT INTO SATURDAY WITH THE POTENTIAL FOR
HEAVIER SNOW ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF CAPITAL
DISTRICT.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE END OF THE WEEK AS COLD AIR WILL BE IN PLACE ACROSS
THE REGION.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...GJM
LONG TERM...NAS
AVIATION...KGM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
347 PM EST THU JAN 19 2012
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT AS A LOW PRESSURE SYSTEM TRACKS
ACROSS SOUTHEASTERN CANADA. ITS ASSOCIATED COLD FRONT WILL SWING
THROUGH OUR AREA LATE TONIGHT. MORE HIGH PRESSURE WILL BUILD INTO
THE MID ATLANTIC FOR FRIDAY. OVER THE WEEKEND, LOW PRESSURE WILL
DELIVER UNSETTLED WEATHER TO THE REGION SATURDAY, FOLLOWED BY HIGH
PRESSURE SETTLING IN FOR SUNDAY. MORE LOW PRESSURE MAY AFFECT OUR
AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE GFS AND WRF-NMM INITIALIZATION LOOKED PRETTY GOOD OFF OF THE 12Z
SOUNDINGS WITH NEITHER MODEL FAVORED. THE ECMWF AND HRRR VERIFIED
THE BEST WITH THE QPF GEOGRAPHICAL EXTENT TO OUR WEST AT 18Z AND THE
FORMER WAS USED TO FINE TUNE THE WX GRIDS FOR TONIGHT. THE MODELS
TRENDED COLDER AND THUS LESS OF A GEOGRAPHICAL MENTION OF RAIN FOR
TONIGHT.
THERE HAS NOT BEEN MUCH OF A MODEL CHANGE WITH RESPECT TO FORCING
AND THE LACK OF MOISTURE WITH WHAT UNDER OTHER CIRCUMSTANCES COULD
HAVE BEEN A MORE DYNAMICAL SYSTEM. THE ACTIVE SNOW AREA TO OUR NW IS
IN THE EXIT REGION OF A 160KT JET WHICH IS FORECAST TO WEAKEN
TONIGHT, BUT STILL WILL PASS ACROSS THE NORTHERN PART OF OUR CWA.
THE ISENTROPIC LIFT (AT 280K) AND THETA E ADVT PART OF THIS EVENT IS
FORECAST TO PASS OFFSHORE BY 00Z. MOST OF THEIR WORK IS TO TRY TO
BRING SOME MSTR INTO OUR CWA, BUT THE SOURCE REGION TO OUR SW IS
QUITE DRY. SO WHEN THE EXIT RGN OF THE JET AND THE FCST DEEP LEVEL
QVEC CONVERGENCE ARRIVE, THE WAA PART OF THE PROGRAM IS OVER. FOR
BETTER OR WORSE THIS DISCONTINUITY GOES A LONG WAY TOWARD GENERATING
THE LOW QPF ALL OF THE MODELS ARE FORECASTING.
NEVERTHELESS GIVEN THE LAST COUPLE OF FEATURES, WE INCREASED POPS
FAR NORTH FOR WATER EQUIVALENTS WHICH WILL PROBABLY BE ONLY SEVERAL
HUNDREDTHS. A QUARTER OF AN INCH OR GREATER SNOW FOLLOWED THE .01
QPF OFF THE ECMWF. THE NEXT SLICE DOWN THROUGH THE I95 CORRIDOR
WE SUGGEST A DUSTING POSSIBLE BY MORNING. FARTHER SE, WARMER
ANTECEDENT SURFACE TEMPS AND LIGHTER INTENSITY MIGHT MIX IN SOME
RAIN, BUT REGARDLESS SHOULD RESULT IN NO EXPECTED DUSTINGS.
THE MODELS TRY TO SHOW A POSSIBLE SECOND QPF MAX ALONG THE NJ COAST
(A COUPLE OF HUNDREDTHS MAYBE) LATE. THIS IS RELATED TO ANOTHER QVEC
CONVERGENCE AREA TRYING TO CATCH UP TO THE PRE FRONTAL ENVIRONMENT.
REASON FOR A POP IN THE POPS TOWARD MORNING THERE.
BECAUSE OF THE SW FLOW AND CLOUDS PRECEDING THE COLD FRONT WE
PREFERRED THE SLIGHTLY HIGHER DATASETS FOR MINS. THE OVERALL
STRENGTH OF THE FCST LLJ IS ABOUT 5-10 KTS LOWER THAN THE 00Z
SOUNDING RUN, SO WE LOWERED LAND BASED GUSTS EAST ABOUT THE SAME AMT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A QUIET AND SEASONABLY COLD DAY IS FORECAST FOR FRIDAY. THE SOUNDING
INVERSION NORTHWEST SINKS RATHER QUICKLY SO WE LIMITED THE MENTION
OF FLURRIES IN THE POCONOS TO EARLY. THE FORECAST CONVECTIVE
TEMPERATURES GET PRETTY HIGH, SO WE ARE NOT EXPECTING MUCH HOME
GROWN CUMULUS CLOUDS. BY THE AFTERNOON WE SHOULD START SEEING THE
CIRRUS CLOUDS ASSOCIATED WITH THE NEXT SYSTEM. BASED ON THE FORECAST
FULL SUN MACROS, THE SLIGHTLY WARMER GFS MOS WAS PREFERRED FOR
TEMPERATURES. THERE MAY BE SOME WIND GUSTS IN THE MORNING, BUT
OVERALL THE WINDS WILL BE CLOSER TO SEASONAL AVERAGE AND NOT AS
ROBUST AS THE PREVIOUS COLD FRONTAL PASSAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
ACTIVE WEATHER WILL START OFF THE LONG TERM PERIOD AS ORGANIZING LOW
PRESSURE TO OUR SOUTHWEST APPROACHES FRIDAY NIGHT AND MOVES OVER THE
REGION DURING SATURDAY. MODEL ANALYSIS AND LOOKING AT FCST SOUNDINGS
CONTINUE TO DEPICT THIS AS A MIXED PRECIPITATION EVENT WITH AMPLE
MOISTURE MOVING OVER THE AREA AND SUFFICIENT COLD AIR IN PLACE AT
THE SURFACE TO START THE EVENT. MOST OF THE FORECAST AREA WILL
LIKELY SEE LIGHT SNOW AT THE ONSET OF PRECIPITATION DURING THE EARLY
MORNING HOURS OF SATURDAY. BUT WITH WARM ADVECTION TAKING PLACE
DURING THE COURSE OF SATURDAY, A TRANSITION TO SLEET OR EVEN
FREEZING RAIN AND THEN TO RAIN APPEARS PROBABLE FROM LATE MORNING TO
AFTERNOON FOR OUR SOUTHERN AND CENTRAL COUNTIES. THE TRANSITION TO
WINTRY MIX MAY REACH THE LEHIGH VALLEY, BUT AREAS IN THE POCONOS AND
NORTHWEST NJ LOOK TO RECEIVE PRIMARILY SNOW FROM THIS EVENT, WITH
SEVERAL INCHES OF ACCUMULATION PROBABLE AT THIS TIME. A WINTER STORM
WATCH HAS BEEN ISSUED WITH THIS FORECAST PACKAGE FOR CARBON AND
MONROE COUNTIES IN PA AND SUSSEX COUNTY IN NJ AS ACCUMULATIONS
RANGING FROM 4 TO 7 INCHES ARE ANTICIPATED AT THIS TIME. THE EURO IS
A BIT SLOWER THAN THE GFS WITH THE PASSAGE OF THIS SYSTEM OVER THE
REGION, WITH PRECIPITATION PROGGED TO LAST LONGER INTO SATURDAY
NIGHT. THE GFS WAS FAVORED A BIT WITH THE FASTER ONSET OF
PRECIPITATION WITH THE EVENT, AND ITS ALSO NOTED THAT THE GFS HAS
TRENDED COLDER.
DURING SUNDAY, STRONG HIGH PRESSURE SPREADS SOUTHWEST FROM EASTERN
CANADA AS THE LOW PRESSURE SYSTEM PUSHES EAST AND OUT TO SEA.
QUIETER CONDITIONS GENERALLY ARE EXPECTED TO RETURN SUNDAY, ALTHOUGH
THE MODELS HINT AT THE POSSIBILITY OF A COLD AIR DAMMING SITUATION
DEVELOPING. THE ODDS ON THIS HAPPENING AS EARLY AS SUNDAY ARE NOT
GREAT, AND THE SUNDAY POPS WITH THIS FORECAST ARE LOW. ANOTHER LOW
PRESSURE SYSTEM IS EXPECTED TO AFFECT OUR FORECAST AREA AS EARLY AS
SUNDAY NIGHT IN THE ACTIVE PATTERN. THIS LOW PRESSURE ORGANIZES OVER
THE CENTRAL PLAINS STATES DURING SUNDAY AND TRACKS NORTHEASTWARD TO
THE GREAT LAKES REGION SUNDAY NIGHT THROUGH MONDAY. ITS ASSOCIATED
FRONTS WILL MOVE THROUGH OUR REGION MONDAY AND MONDAY NIGHT.
TEMPERATURES AND THERMAL FIELDS GENERALLY ARE MILD ENOUGH TO SUPPORT
RAIN WITH THE PASSAGE OF THIS SYSTEM, ALTHOUGH COLD AIR THANKS TO
THE RECEDING HIGH TO THE NORTHEAST MAY GENERATE A PERIOD OF SNOW
CHANGING TO FREEZING RAIN FOR A WHILE NORTH. THE EURO AGAIN IS
SLOWER THAN THE GFS WITH THE PROGRESSION OF THIS SYSTEM THROUGH THE
EASTERN STATES. HOWEVER, AT THIS TIME, IT APPEARS THAT THIS SYSTEM
PUSHES EAST OF OUR AREA OVERNIGHT MONDAY. AFTER THAT, THE MODELS ARE
QUITE DIVERGENT (EVEN WITHIN THEMSELVES FROM RUN TO RUN).
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LATEST 18Z TAFS KEEP A VFR FORECAST GOING, BUT CONFIDENCE IS
LOWEST AT KABE.
A RAPID INCREASE IN MID AND HIGH LEVEL CLOUDINESS WILL CONTINUE THE
REST OF THE AFTERNOON. AS THE HIGH MOVES OFFSHORE, THERE WILL BE A
WINDOW FOR SOME BREEZINESS AND GUSTS FOR AROUND 15 KT WERE
MAINTAINED.
FOR TONIGHT, SNOW SHOWERS AND FLURRIES ASSOCIATED WITH AN
APPROACHING COLD FRONT WILL WORK THEIR WAY INTO THE TERMINALS.
GREATEST CHANCE FOR MVFR AND MAYBE EVEN BRIEFLY VSBY RELATED IFR
RESTRICTIONS IS EXPECTED AT LOCAL AIRPORTS NORTH OF A KRDG-KABE-
KTTN LINE WHERE FCST MOISTURE IS DEEPEST. SO IF WE ARE TOO
OPTIMISTIC ABOUT OUR TERMINALS, KABE IS MOST VULNERABLE. CIGS ARE
FORECAST TO LOWER, BUT REMAIN VFR.
THE COLD FRONT SHOULD CLEAR THE TERMINALS FROM AROUND 09Z TO 11Z FROM
WEST TO EAST AND END ANY SNOW CHANCES. THE GRADIENT BEHIND THE
FRONT IS NOT THAT STRONG AND GUSTS WERE ONLY INCLUDED AT OUR TWO
WINDIEST AIRPORTS, KPHL AND KACY.
VFR CONDITIONS WITH NO CIGS ARE THEN FORECAST TO RETURN DURING
THE DAYLIGHT MORNING.
OUTLOOK...
LOW PRESSURE APPROACHES AND MOVES OVER THE REGION FROM FRIDAY NIGHT
THROUGH SATURDAY, BRINGING THE POTENTIAL FOR MIXED WINTRY
PRECIPITATION TO THE FORECAST AREA. LOWER CEILINGS AND VISIBILITIES
ARE EXPECTED DURING THIS TIMEFRAME. DEPENDING ON HOW QUICKLY THE
SYSTEM EXITS THE REGION, LOWER CONDITIONS MAY EXTEND INTO EARLY
SUNDAY. THE NEXT LOW PRESSURE SYSTEM THAT MAY AFFECT THE AREA,
BRINGING RAIN ALONG WITH LOWERED CEILING AND VISIBILITY VALUES, IS
EXPECTED SUNDAY NIGHT TO MONDAY NIGHT.
&&
.MARINE...
THE SMALL CRAFT ADVISORY WAS EXTENDED INTO FRIDAY MORNING FOR ALL
MARINE AREAS. THE INCREASING SW FLOW SHOULD BRING SMALL CRAFT
CONDITIONS TONIGHT. EVEN THOUGH THE WINDS ARE SOUTHWEST, IN THIS
INSTANCE IT STILL WILL BE COLDER AIR PASSING OVER WARMER WATER.
THERE WILL BE A LULL LATE AS THE COLD FRONT NEARS, BUT THEN COULD BE
A COUPLE OF HOUR WINDOW OF OPPORTUNITY FOR MORE SCA CONDITIONS IN
THE FRESH COLD AIR ADVECTION BEHIND THE COLD FRONT ON FRIDAY
MORNING. AS THE NEXT HIGH PRESSURE SYSTEM THEN NEARS, BOTH WINDS AND
SEAS SHOULD DROP BELOW SMALL CRAFT ADVISORY CRITERIA BY THE
AFTERNOON.
WITH LOW PRESSURE MOVING OVER THE AREA SATURDAY THROUGH SATURDAY
NIGHT, REACHING SMALL CRAFT ADVISORY CRITERIA FOR SEAS IS EXPECTED,
THANKS TO A PERSISTENT EAST TO NORTHEAST FLOW. THE ELEVATED SEAS IN
THE 5 TO 6 FOOT RANGE ON OUR WATERS ARE ANTICIPATED SATURDAY NIGHT
THROUGH SUNDAY, AND THE ELEVATED SEAS MAY EXTEND INTO MONDAY WITH
THE PASSAGE OF ANOTHER WEATHER SYSTEM. WINDS AND GUSTS MAY
OCCASIONALLY REACH ADVISORY LEVELS DURING THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR PAZ054-055.
NJ...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR NJZ001.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
FRIDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...DELISI/KLINE
AVIATION...DELISI/GIGI/KLINE
MARINE...DELISI/GIGI/KLINE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
921 AM EST THU JAN 19 2012
.SYNOPSIS...
AN AREA OF HIGH PRESSURE OVER THE LOWER HUDSON VALLEY IN NEW YORK
STATE WILL MOVE OFF TO THE EAST THROUGH TONIGHT. LOW PRESSURE WILL MOVE
ACROSS ONTARIO AND QUEBEC TODAY AND TONIGHT. IT WILL CAUSE A COLD
FRONT TO MOVE ACROSS OUR REGION. MORE HIGH PRESSURE WILL SETTLE
ACROSS THE AREA FRIDAY AND THEN WITHDRAW EASTWARD FRIDAY NIGHT.
ANOTHER LOW PRESSURE SYSTEM WILL BRING MORE UNSETTLED WEATHER TO
THE AREA SATURDAY. MORE HIGH PRESSURE WILL FOLLOW FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE ESTF UPDATE WAS BASICALLY SOME SMALL POP TWEAKING. TEMPS, DEWS
AND WINDS ARE LOOKING GOOD. THE HRRR WAS VERIFYING THE BEST OF
THE MODELS (RGEM SECOND) AS TO WHERE THE SNOW WAS REACHING THE
GROUND IN THE GREAT LAKES. BASED ON THOSE MODELS AND A QUICK
GLANCE AT THE NEW SREF, WE SLOWED THE ARRIVAL OF THE SNOW SLIGHTLY
FAR NORTHWEST.
AHEAD OF THE SHORT WAVE...SURFACE HIGH PRESSURE WILL CREST OVER THE
REGION THIS MORNING...THEN MOVE OFFSHORE THIS AFTERNOON. 0000 UTC
SOUNDINGS ACROSS THE AREA WHERE BONE DRY (WITH PRECIPITABLE WATER
VALUES NEAR 0.10 INCHES). THE ENTIRE COLUMN IS DRY...AND THE WARM
AIR ADVECTION AHEAD OF THE IMPRESSIVE SHORT WAVE WILL GO INTO
MOISTENING THE COLUMN. THIS WILL MANIFEST ITSELF AS INCREASING HIGH
AND THEN MID LEVEL CLOUDINESS.
THE COLUMN COULD MOISTEN IN THE BETTER WARM AIR ADVECTION ENOUGH
ACROSS THE LEHIGH VALLEY AND THE SOUTHERN POCONOS FOR SOME FLURRIES
LATE...BUT BASED ON HOW DRY THE AIRMASS IS NOW...EVEN THESE
LOCATIONS SHOULD STAY DRY THROUGH DUSK. MODEL SOUNDINGS SUGGEST THAT
MOS VALUES ARE CLOSE FOR HIGHS...AND A BLEND WAS USED FOR TODAY.
AS THE SURFACE HIGH GETS FARTHER EAST THIS MORNING...THE RETURN
FLOW INCREASES THIS AFTERNOON. MODEL SOUNDINGS SHOW THE DEPTH OF
THE MIXED LAYER WILL BE ENOUGH FOR SOUTHERLY WINDS TO GUST TO 20
MPH THIS AFTERNOON...MAINLY NEAR THE COAST AND IN THE HIGHER
TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
THE MAIN FORECAST PROBLEM FOR TONIGHT INCLUDE PRECIPITATION
COVERAGE...SNOW AMOUNTS...AND WHETHER THE LOW LEVEL JET WILL PRODUCE
WIND GUSTS NEAR THE COAST AFTER MIDNIGHT.
THE APPROACHING SHORT WAVE WILL TRY TO INDUCE A LAYER OF MID LEVEL
FRONTOGENETIC FORCING ACROSS CENTRAL AREAS THIS EVENING. THE AIRMASS
WILL STILL BE FAIRLY DRY...AS THE WAA INDUCED LIFT NOW AHEAD OF THE
SHORT WAVE IS MOSTLY DRY. THE FRONTOGENETIC FORCING APPEARS TO BE
MAXIMIZE DURING THE EVENING HOURS ACROSS CENTRAL AND NORTHERN
AREAS. IT WOULD APPEAR AS THOUGH THE SOUTH TO SOUTHWEST CROSS
BARRIER FLOW ACROSS THE HIGHER TERRAIN WILL HELP SQUEEZE OUT THE
AVAILABLE MOISTURE. THE COMBINATION OF LIFT AND SQUEEZING DUE TO
OROGRAPHIC EFFECTS SHOULD ALLOW NORTHERN AREAS SEE LIGHT SNOW
DEVELOP THIS EVENING.
QPF AMOUNTS FOR THIS EVENT ARE RATHER MEAGER...BASED ON WHAT IS
OCCURRING UPSTREAM AND THE GENERAL DRYNESS OF THE AIRMASS IN PLACE.
RIGHT NOW...IT LOOKS LIKE THE HIGHER TERRAIN OF THE SOUTHERN POCONOS
AND NORTHWEST NEW JERSEY. THE BEST DYNAMIC LIFT ASSOCIATED WITH THE
SHORT WAVE SHOULD PASS NORTH OF THE AREA...AND BASED ON THE QPF WE
COULD SEE AN INCH OR TWO IN THE HIGHER TERRAIN.
FURTHER SOUTH...THE SOUTHERN EXTENT OF THE PRECIPITATION BECOMES A
BIT MORE NEBULOUS. THE WARM AIR ADVECTION WILL MOISTEN THE
COLUMN...BUT ONLY TO A POINT. IT WOULD APPEAR THAT AREAS SOUTH OF AN
KMQS-KPHL-KACY LINE MAY BE JUST TOO DRY FOR THE WARM AIR ADVECTION
TO BE OF MUCH HELP. IN BETWEEN THE HIGHER TERRAIN AND THE
ABOVEMENTIONED LINE...PRECIPITATION CHANCES WERE GRADUATED FROM
NORTH TO SOUTH.
THE WARM AIR ADVECTION MAY ALSO PLAY HAVOC WITH LIGHT PRECIPITATION
TYPE. IN PLACES WHERE PRECIPITATION IS STEADY...THE EVAPORATIVE
COOLING SHOULD ALLOW A NEAR ISOTHERMAL PROFILE...AND THE SNOW SHOULD
BE THE MAIN PRECIPITATION TYPE. FOR THE LOWER LEHIGH VALLEY THROUGH
THE DELAWARE VALLEY INTO CENTRAL NEW JERSEY...THE PRECIPITATION TYPE
COULD BE DOMINATED BY PRECIPITATION RATES...AND THE FURTHER SOUTH
ONE GOES INTO THE AIRMASS IN PLACES...A MIX OF RAIN COULD BE MORE
THE DOMINANT TYPE DUE TO CONTINUED WARM AIR ADVECTION.
SINCE TEMPERATURES HAVE BEEN COLD THE PAST DAY OR SO...COLDER
SURFACES MAY BE ABLE TO SUPPORT LIGHT SNOW ACCUMULATIONS OUTSIDE OF
THE TERRAIN. FOR NOW...HOWEVER...SNOWFALL AMOUNTS APPEAR TO BE LESS
THAN AN INCH.
THE MAIN THRUST OF WARM AIR ADVECTION INDUCED PRECIPITATION SHOULD
EXIT THE AREA AHEAD OF THE COLD FRONT ASSOCIATED WITH THE STRONG
SHORT WAVE. AHEAD OF THE FRONT IN THE WARM AIR ADVECTION...MODEL
SOUNDINGS ARE SUGGESTING THAT DELAWARE AND COASTAL NEW JERSEY COULD
SEE MIXING LAYERS DEEP ENOUGH TO SUPPORT WIND GUSTS TO 35 MPH AS A
LOW LEVEL JET CROSSES AREAS LATE THIS EVENING AND OVERNIGHT. AS IS
USUALLY THE CASE WITH WARM AIR ADVECTION AND LOWERING INVERSIONS...
THE GUSTINESS OF THE WINDS APPEAR TO BE PROBLEMATIC. FOR NOW WIND
GUSTS WILL BE KEPT BELOW 35 MPH ALONG THE COAST...AND IN ANY EVENT
DO NOT APPEAR TO SUPPORT WIND ADVISORY CRITERIA.
TEMPERATURES PROBABLY DROP A BIT THIS EVENING...THEN REMAIN MORE OR
LESS STEADY THROUGH THE COLD FRONTAL PASSAGE. SINCE MOS SEEMS TO BE
PICKING UP ON THIS...A BLEND OF MOS NUMBERS WAS USED FOR LOWS.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FAIR WEATHER IS EXPECTED FRI AS HIGH PRESSURE BUILDS BACK ACROSS
THE AREA. A FEW LINGERING NOW SHOWERS MAY CONTINUE EARLY IN THE
DAY ACROSS THE SOUTHERN POCONOS.
THE NEXT SYSTEM WILL BRING MORE CLOUDS AND PRECIPITATION TO THE
AREA SATURDAY INTO SATURDAY NIGHT. IT APPEARS THAT THE NORTHERN
AREAS WILL BE COLD ENOUGH FOR (MOSTLY) SNOW AND MAYBE SOME SLEET
WITH THE LOW. SOME ACCUMULATIONS WILL OCCUR...MAYBE SEVERAL
INCHES...AND WWA FLAGS MAY BE NEEDED IN UPCOMING FCSTS. THE LOW
WILL BRING SOME SNOW TO CENTRAL AREAS OF NJ AND METRO
PHILADELPHIA TOO...BUT TEMPERATURES MAY WARM ENOUGH TO CAUSE A
CHANGE OVER TO RAIN DURING THE DAY...REDUCING THE ACCUMULATIONS.
MOSTLY RAIN IS EXPECTED ACROSS THE DELMARVA. THE SYSTEM MOVES TO
THE EAST SAT NIGHT AND PRECIPITATION SHOULD END BY SUN MORNING.
FAIR WEATHER IS EXPECTED SUN AS HIGH PRESSURE WEDGES DOWN FROM
CANADA. ANOTHER LOW WILL DEEPEN ACROSS THE PLAINS AND SEND MORE
WARM AIR AND RAIN TO THE AREA MON-TUE. THE LATEST EC IS SLOWER
WITH THIS SYSTEM AS COMPARED TO THE GFS...SO WITH THE MODEL
DIFFERENCES...FEW CHANGES WERE MADE IN THE TUE OR WED PERIODS OF
THE FCST.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE IS ABOUT TO CREST OVER THE REGION... WHICH
IS KEEPING A BIT OF A NORTH TO NORTHEAST GRADIENT AHEAD OF THE
HIGH...AND THIS IS IN TURN KEEPING WINDS FROM BECOMING LIGHT AND
VARIABLE. THIS WILL LIKELY HAPPEN BEFORE SUNRISE.
VFR CONDITIONS ARE EXPECTED TODAY...AS HIGH AND MID LEVEL CLOUDINESS
INCREASE AND THICKEN. THE LIGHT NORTH TO NORTHEAST GRADIENT EARLY
THIS MORNING WILL DIMINISH...AND AS THE SURFACE HIGH GETS
OFFSHORE...THE RETURN FLOW INCREASES THIS AFTERNOON. MODEL SOUNDINGS
SUGGEST THAT WIND GUSTS TO ABOUT 18 KNOTS ARE POSSIBLE THIS
AFTERNOON...AND THE WIND DIRECTION LOOKS TO BE 180-190 DEGREES. THIS
MAY HAVE SOME OPERATIONAL IMPACT AT KPHL THIS AFTERNOON...BUT THE
GUSTS ARE EXPECTED TO DIMINISH BY 2300 UTC.
A COLD FRONT APPROACHING THE REGION THIS AFTERNOON AND EVENING WILL
ALLOW LOWER CLOUDS TO DEVELOP AHEAD OF IT. THE COLD FRONT HAS A BAND
OF SNOW WITH AND JUST AHEAD OF IT ACROSS THE WESTERN GREAT LAKES
EARLY THIS MORNING. IT APPEARS AS THOUGH THE FORCING FOR THE SNOW
WILL PASS MAINLY NORTH OF THE AREA TONIGHT...BUT COULD CLIP KABE AND
PERHAPS KRDG WITH LIGHT SNOW. THE 0600 UTC INCLUDES MVFR CONDITIONS
FOR LIGHT SNOW AT KABE AND HINTS AT THE POTENTIAL FOR KRDG.
FURTHER SOUTH...IT IS NOT CLEAR JUST HOW MUCH OF AN IMPACT
PRECIPITATION WILL HAVE. THE AIRMASS WILL WARMER AT THE KPHL METRO
AIRPORTS...SO THE PRECIPITATION COULD FALL AS RAIN OR SNOW. VFR
CONDITIONS WITH THE POSSIBILITY OF LIGHT RAIN AND SNOW IS INDICATED
AT KTTN AND KPNE...BUT NO FURTHER SOUTH AND EAST.
THE FINAL FORECAST ISSUE FOR TONIGHT IS THE POTENTIAL FOR LOW LEVEL
WIND SHEAR. SHORT TERM MODELS SHOW A 40 TO 45 KNOT LOW LEVEL JET
IMPACT THE REGION BETWEEN 0300 AND 0900 UTC FRIDAY. THE INVERSION WILL
LOWER TONIGHT AHEAD OF THE LOW LEVEL JET...AND FOR NOW THE LLWS
REMARK WAS OMITTED FROM THE TERMINAL FORECASTS. THIS WILL BE
REVISITED FOR THE 1200 UTC FORECASTS/
IMPROVED CONDITIONS WILL ARRIVE BEHIND THE DEPARTING SYSTEM ON
FRIDAY WITH VFR EXPECTED FRI MORNING. THIS WILL CARRY INTO THE
EVENING BEFORE THE NEXT SYSTEM APPROACHES FOR SAT MORNING. MORE
WIDESPREAD POOR FLYING WEATHER IS ANTICIPATED FOR SAT AND SAT
NIGHT.
&&
.MARINE...
A SMALL CRAFT ADVISORY WILL BE RAISED WITH THE NEW FORECAST FOR ALL
MARINE ZONES FOR TONIGHT.
THE SURFACE GRADIENT AHEAD OF THE HIGH APPROACHING FROM THE WEST HAS
KEPT THE WINDS BETWEEN 15 AND 20 KNOTS THROUGH THE EARLY MORNING
HOURS. SURFACE STREAMLINES TO THE WEST SUGGEST THIS WILL CHANGE
SOON...AS WINDS DROP OFF...AND VEER TO THE NORTHEAST. AS THE HIGH
GETS OFFSHORE LATER THIS MORNING...THE FLOW WILL VEER TO THE SOUTH
SOUTHWEST.
THE GRADIENT LOOKS AS THOUGH IT CAN SUPPORT GUSTS TO NEAR
20 KNOTS LATE THIS AFTERNOON OVER THE SOUTHERN OCEAN WATERS AND
ACROSS DELAWARE BAY. HOWEVER...MODEL SOUNDINGS MAY BE A BIT TOO
GENEROUS WITH MIXING IN AN INCREASING WARM AIR ADVECTION PATTERN...
AND WINDS AND SEAS WILL BE KEPT BELOW SMALL CRAFT LEVELS THROUGH
DUSK.
AS A COLD FRONT APPROACHES THIS EVENING...THE SURFACE GRADIENT LOOKS
TO BE ABLE TO SUPPORT SMALL CRAFT WINDS ACROSS ALL WATERS...PROBABLY
STARTING IN THE NEIGHBORHOOD OF 0000 UTC. MODELS HAVE BEEN
CONSISTENT SHOWING A LOW LEVEL JET CROSSING THE REGION LATE THIS
EVENING AND DURING THE OVERNIGHT. MODEL SOUNDINGS SHOW A 3 HOUR
WINDOW (CENTERED AROUND 0600 UTC FRIDAY) WHERE 30 TO 35 KNOTS OF
WIND DROP BELOW THE INVERSION.
TYPICALLY...IT IS DIFFICULT TO GET A SOUTHWEST FLOW IN STRONG WARM
AIR ADVECTION TO WORK ITS WAY BELOW A LOWERING INVERSION...AND THIS
LOOKS LIKE A TYPICAL WARM AIR ADVECTION PATTERN. WHILE THE SIGNATURE
IS PRESENT IN BOTH THE NAM AND GFS AT 44009...WILL HOLD OFF ON
ISSUING A GALE WARNING. HOWEVER...30 KNOT GUSTS WILL BE INCLUDED IN
THE FORECAST FOR THE SOUTHERN OCEAN WATERS AND THE LOWER DELAWARE
BAY...WHERE THE LOW LEVEL JET WILL MAKE ITS CLOSEST PASS. IF ANY
PLACES END UP NEEDING A SHORT FUSED GALE WARNING TONIGHT...IT WOULD BE
THE ABOVEMENTIONED LOCATIONS.
THE COLD FRONT IS EXPECTED TO CROSS THE COASTAL WATERS BETWEEN 0800
AND 1200 UTC FRIDAY. THE COLD AIR ADVECTION BEHIND THE COLD FRONT
DOES NOT APPEAR TO BE SUFFICIENT TO KEEP WINDS AT SMALL CRAFT
LEVELS. THEREFORE...THE SMALL CRAFT ADVISORY WILL COVER JUST THE
TONIGHT PERIOD.
MORE SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP ON THE WATERS
WITH THE SYSTEM THAT WILL AFFECT THE WATERS SATURDAY NIGHT AND
SUNDAY. THE ENHANCED SEAS MAY PERSIST INTO MONDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST FRIDAY
FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GIGI/HAYES
SHORT TERM...HAYES
LONG TERM...O`HARA
AVIATION...HAYES/O`HARA
MARINE...HAYES/O`HARA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1221 PM EST THU JAN 19 2012
.AVIATION...VFR CONDITIONS EXPECTED NEXT 24 HRS. SURFACE WINDS
FROM NE AROUND 10 KNOTS SHOULD DECREASE TO AROUND 4-5 KNOTS
OVERNIGHT. SFC HIGH PRESSURE MOVING TO WESTERN ATLANTIC SHOULD
RESULT IN SFC WINDS BECOMING MORE EAST AND INCREASING TO AROUND 10
KTS BY MID MORNING FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 924 AM EST THU JAN 19 2012/
UPDATE...
A WEAK BOUNDARY WAS MOVING THROUGH SOUTH FLORIDA THIS MORNING. THE
ONLY NOTABLE FEATURE IS THE CLOUD COVER ACROSS DEEP SOUTH FLORIDA.
THIS BOUNDARY WILL BECOME EVEN MORE DIFFUSE LATER TODAY...BUT DRIER
AIR WILL CONTINUE TO FILTER INTO THE REGION. SLIGHTLY COOLER
TEMPERATURES ARE EXPECTED THIS AFTERNOON. NO MAJOR UPDATES NEEDED
THIS MORNING.
PREV DISCUSSION... /ISSUED 546 AM EST THU JAN 19 2012/
AVIATION...WEAKENING COLD FRNT APRCHG LK OKEE AREA AND WL MOV
INTO S FLA AND MOV OFF OF THE SE COAST ARND 15Z. MVFR CIGS WITH
LCL IFR OCCURRING AHD OF FRNT. MVFR CIGS PSBL E COAST TERMINALS
11Z-14Z THEN VFR ALL TERMINALS THRU THE END OF THE PD. SFC WNDS
NNW-N < 10 KTS BCMG NNE ALL TERMINALS AFT 18Z AND INCRG 10 TO 15
KTS THEN DCRG < 10 KTS AFT 00Z. POTENTIAL EXISTS THAT AN OFSHR
WND FLOW MAY DVLP LATE TONIGHT BUT NOT IN TAFS ATTM.
PREV DISCUSSION... /ISSUED 324 AM EST THU JAN 19 2012/
DISCUSSION...
LATEST DEW POINT SURFACE ANALYSIS REVEALS LEADING EDGE OF WEAK
FRONTAL BOUNDARY CURRENTLY ACROSS SOUTH CENTRAL FLORIDA BETWEEN
ORLANDO AND LAKE OKEECHOBEE. ANALYSIS OF MODEL GUIDANCE TRACKING THIS
FEATURE INDICATES THE BOUNDARY WILL BE ACROSS SOUTH FLORIDA BY
LATE MORNING AND/OR EARLY AFTERNOON. GLOBAL MODELS IN FACT BRING
IT THROUGH THE AREA BUT THE HIRES MODELS INCLUDING NCEP HIRES NMM
AND ARW AS WELL AS THE LOCAL WRF AND THE RUC INDICATE THE BOUNDARY
WILL SIMPLY DISSIPATE ACROSS THE AREA AS IT MOVES INTO SOUTH
FLORIDA TODAY. EITHER WAY DRIER AIR WILL BE MOVING INTO THE AREA
WITH IT. AHEAD OF IT, RADAR AND SATELLITE INDICATED SOME
CONVECTION EARLIER THIS MORNING MOVING INTO THE GULF WATERS BUT
IT HAS DISSIPATED SINCE THEN AS LOW LEVEL FORCING WITH THE FRONT
WEAKENS AND AS IT MOVES FARTHER AWAY FROM UPPER LEVEL DYNAMICS
WELL REMOVED TO THE NORTH. SO FAR LOOKS LIKE CLOUDS ASSOCIATED
WITH THE APPROACHING BOUNDARY ARE PREVENTING PATCHY FOG FROM
DEVELOPING THIS MORNING ACROSS INTERIOR AREAS OF SOUTH FLORIDA AND
THAT IS LIKELY TO REMAIN LIKE THAT BUT WILL CONTINUE TO MONITOR
JUST IN CASE. FOR THE MOMENT GIVEN TRENDS LEFT THAT OUT OF THE
FORECAST FOR THIS MORNING.
AHEAD OF THE BOUNDARY TODAY THERE WILL BE ONLY A SLIGHT CHANCE OF A
SHOWER, BEST OVER THE COASTAL WATERS, WITH DRIER AIR MASS
GRADUALLY MOVING IN PARTICULARLY BEGINNING AROUND MID TO LATE
MORNING AND INTO THE EARLY AFTERNOON. YET RAIN CHANCES NOT ENOUGH
TO MENTION IN THE FORECAST. AS ALLUDED TO ABOVE, THE BOUNDARY IS
EXPECTED TO STALL AND DISSIPATE BETWEEN MAINLAND SOUTH FLORIDA AND
THE STRAITS THROUGH TONIGHT. TEMPERATURES WILL CONTINUE TO BE WARM
WITH HIGHS IN THE 70S TODAY...AND THEN INTO THE UPPER 70S TO THE
LOWER 80S BY FRIDAY AND INTO THE WEEKEND. WITH THE DRIER AIR AND
EXCELLENT RADIATIONAL COOLING...OVERNIGHT LOWS TONIGHT MAY GET
INTO THE MID 40S ACROSS THE NORTHWEST INTERIOR. ALSO WITH LIGHT
WINDS AND LOW LEVEL FLOW TURNING FROM THE NORTHEAST, IT IS
POSSIBLE THAT PATCHY FOG DEVELOPS INLAND AROUND LAKE OKEECHOBEE
TONIGHT AND AGAIN FRIDAY NIGHT. HOWEVER, CHANCES OF THAT ARE BEST
FRIDAY NIGHT AS BY THEN RETURN FLOW FROM THE ATLANTIC WOULD HAVE
HAD MORE TIME TO MOISTEN UP THE LOW LEVELS A BIT. BUT GIVEN ALL
MOS GUIDANCE DEVELOP IT TONIGHT ALSO, I PUT IT IN THE GRIDS.
OVERALL TONIGHT WILL BE THE COOLEST NIGHT OF THE COMING WEEK. A
CAVEAT HERE IS THAT THE MET GUIDANCE IS SIGNIFICANTLY WARMER THAN
THE MAV FOR NORTHEAST PORTIONS OF THE AREA (PALM BEACH COUNTY). NAM
IS BANKING ON LOT OF CLOUDS RETURNING QUICKLY WITH LOW LEVEL FLOW
SHIFTING FROM THE NE. BUT AT THIS TIME DECIDED TO STICK WITH MAV.
FLOW WILL NOT BE THAT STRONG AND A LAND BREEZE COULD PREVENT THIS
SCENARIO FROM HAPPENING TOO. EKDMOS ENSEMBLE GUIDANCE ALSO SHOWS A
MEAN IN THE MID TO UPPER 50S.
SO WITH THAT SAID, TEMPS TONIGHT WILL STILL BE A COUPLE OF DEGREES
ABOVE NORMAL ACROSS SOUTH FLORIDA WITH A WARMING TREND IN STORE FOR
THE UPCOMING WEEKEND AND INTO THE FIRST PART OF NEXT WEEK WHEN
MODELS GENERALLY AGREE ON HIGH PRESSURE ALOFT BUILDING FROM THE
SOUTHERN GULF OF MEXICO ACROSS CUBA AND INTO THE BAHAMAS, KEEPING
JET STREAM AND STORM TRACKS WELL TO OUR NORTH. GFS IS THE MOST
AGGRESSIVE OF THE MODELS BUILDING THE AFOREMENTIONED HIGH ALOFT BUT
THE MEAN OF THE ENSEMBLE IS STILL CONSISTENT WITH THE SCENARIO AND
SO IS THE ECMWF. BOTTOM LINE, THE ENSUING WARMING TREND WILL RESULT
IN OVERNIGHT LOWS RUNNING CLOSE TO 10 DEGREES ABOVE NORMAL BY LATE
IN THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK ALONG WITH
DAYTIME HIGHS RUNNING AROUND 5 DEGREES ABOVE NORMAL.
IT WILL REMAIN DRY FOR THE MOST PART THROUGH THE WEEKEND WITH A
SLIGHT CHANCE OF SHOWERS MAY BE COMING BACK INTO THE PICTURE BY THE
EARLY TO MIDDLE PART OF NEXT WEEK AS LOW LEVEL MOISTURE SLOWLY
RETURNS FROM THE SOUTH BUT NOT LOOKING TOO PROMISING AT THIS TIME.
MARINE...
A BRIEF SURGE IN WIND OF UP TO 15 TO 20 KNOTS TODAY OFF THE COAST
OF PALM BEACH FROM THE NORTH NORTHEAST WILL RESULT IN A SHORT
LIVED SURGE IN SEAS OF UP TO 6 FEET IN THE GULF STREAM. SO WILL
PUT UP A SMALL CRAFT SHOULD EXERCISE CAUTION FOR THOSE WATERS
TODAY. OTHERWISE WINDS AND SEAS WILL REMAIN BELOW 10 TO 15 KNOTS
AND BELOW 4 FEET INTO THE EARLY PART OF NEXT WEEK.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES TODAY WILL BE BELOW 35 PERCENT IN
AREAS NORTH OF ALLIGATOR ALLEY ACROSS NORTHERN COLLIER, HENDRY,
AND GLADES COUNTIES TODAY FOR CLOSE TO 4 HOURS. HOWEVER ERC VALUES
ACROSS THE AREA REMAIN TOO LOW FOR ANY RED FLAG CONCERNS. AFTER
TODAY, LOW LEVEL MOISTURE WILL BE ON THE INCREASE AND SO NO OTHER
FIRE CONCERNS AT THIS TIME INTO EARLY NEXT WEEK AT THE VERY LEAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 55 76 61 77 / - - - -
FORT LAUDERDALE 61 77 66 78 / - - - -
MIAMI 60 77 65 78 / - - - -
NAPLES 52 78 57 78 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...47/RGH
AREA FORECAST DISCUSSION
NWS MIAMI FL
924 AM EST THU JAN 19 2012
.UPDATE...
A WEAK BOUNDARY WAS MOVING THROUGH SOUTH FLORIDA THIS MORNING. THE
ONLY NOTABLE FEATURE IS THE CLOUD COVER ACROSS DEEP SOUTH FLORIDA.
THIS BOUNDARY WILL BECOME EVEN MORE DIFFUSE LATER TODAY...BUT DRIER
AIR WILL CONTINUE TO FILTER INTO THE REGION. SLIGHTLY COOLER
TEMPERATURES ARE EXPECTED THIS AFTERNOON. NO MAJOR UPDATES NEEDED
THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 546 AM EST THU JAN 19 2012/
AVIATION...WEAKENING COLD FRNT APRCHG LK OKEE AREA AND WL MOV
INTO S FLA AND MOV OFF OF THE SE COAST ARND 15Z. MVFR CIGS WITH
LCL IFR OCCURRING AHD OF FRNT. MVFR CIGS PSBL E COAST TERMINALS
11Z-14Z THEN VFR ALL TERMINALS THRU THE END OF THE PD. SFC WNDS
NNW-N < 10 KTS BCMG NNE ALL TERMINALS AFT 18Z AND INCRG 10 TO 15
KTS THEN DCRG < 10 KTS AFT 00Z. POTENTIAL EXISTS THAT AN OFSHR
WND FLOW MAY DVLP LATE TONIGHT BUT NOT IN TAFS ATTM.
PREV DISCUSSION... /ISSUED 324 AM EST THU JAN 19 2012/
DISCUSSION...
LATEST DEW POINT SURFACE ANALYSIS REVEALS LEADING EDGE OF WEAK
FRONTAL BOUNDARY CURRENTLY ACROSS SOUTH CENTRAL FLORIDA BETWEEN
ORLANDO AND LAKE OKEECHOBEE. ANALYSIS OF MODEL GUIDANCE TRACKING THIS
FEATURE INDICATES THE BOUNDARY WILL BE ACROSS SOUTH FLORIDA BY
LATE MORNING AND/OR EARLY AFTERNOON. GLOBAL MODELS IN FACT BRING
IT THROUGH THE AREA BUT THE HIRES MODELS INCLUDING NCEP HIRES NMM
AND ARW AS WELL AS THE LOCAL WRF AND THE RUC INDICATE THE BOUNDARY
WILL SIMPLY DISSIPATE ACROSS THE AREA AS IT MOVES INTO SOUTH
FLORIDA TODAY. EITHER WAY DRIER AIR WILL BE MOVING INTO THE AREA
WITH IT. AHEAD OF IT, RADAR AND SATELLITE INDICATED SOME
CONVECTION EARLIER THIS MORNING MOVING INTO THE GULF WATERS BUT
IT HAS DISSIPATED SINCE THEN AS LOW LEVEL FORCING WITH THE FRONT
WEAKENS AND AS IT MOVES FARTHER AWAY FROM UPPER LEVEL DYNAMICS
WELL REMOVED TO THE NORTH. SO FAR LOOKS LIKE CLOUDS ASSOCIATED
WITH THE APPROACHING BOUNDARY ARE PREVENTING PATCHY FOG FROM
DEVELOPING THIS MORNING ACROSS INTERIOR AREAS OF SOUTH FLORIDA AND
THAT IS LIKELY TO REMAIN LIKE THAT BUT WILL CONTINUE TO MONITOR
JUST IN CASE. FOR THE MOMENT GIVEN TRENDS LEFT THAT OUT OF THE
FORECAST FOR THIS MORNING.
AHEAD OF THE BOUNDARY TODAY THERE WILL BE ONLY A SLIGHT CHANCE OF A
SHOWER, BEST OVER THE COASTAL WATERS, WITH DRIER AIR MASS
GRADUALLY MOVING IN PARTICULARLY BEGINNING AROUND MID TO LATE
MORNING AND INTO THE EARLY AFTERNOON. YET RAIN CHANCES NOT ENOUGH
TO MENTION IN THE FORECAST. AS ALLUDED TO ABOVE, THE BOUNDARY IS
EXPECTED TO STALL AND DISSIPATE BETWEEN MAINLAND SOUTH FLORIDA AND
THE STRAITS THROUGH TONIGHT. TEMPERATURES WILL CONTINUE TO BE WARM
WITH HIGHS IN THE 70S TODAY...AND THEN INTO THE UPPER 70S TO THE
LOWER 80S BY FRIDAY AND INTO THE WEEKEND. WITH THE DRIER AIR AND
EXCELLENT RADIATIONAL COOLING...OVERNIGHT LOWS TONIGHT MAY GET
INTO THE MID 40S ACROSS THE NORTHWEST INTERIOR. ALSO WITH LIGHT
WINDS AND LOW LEVEL FLOW TURNING FROM THE NORTHEAST, IT IS
POSSIBLE THAT PATCHY FOG DEVELOPS INLAND AROUND LAKE OKEECHOBEE
TONIGHT AND AGAIN FRIDAY NIGHT. HOWEVER, CHANCES OF THAT ARE BEST
FRIDAY NIGHT AS BY THEN RETURN FLOW FROM THE ATLANTIC WOULD HAVE
HAD MORE TIME TO MOISTEN UP THE LOW LEVELS A BIT. BUT GIVEN ALL
MOS GUIDANCE DEVELOP IT TONIGHT ALSO, I PUT IT IN THE GRIDS.
OVERALL TONIGHT WILL BE THE COOLEST NIGHT OF THE COMING WEEK. A
CAVEAT HERE IS THAT THE MET GUIDANCE IS SIGNIFICANTLY WARMER THAN
THE MAV FOR NORTHEAST PORTIONS OF THE AREA (PALM BEACH COUNTY). NAM
IS BANKING ON LOT OF CLOUDS RETURNING QUICKLY WITH LOW LEVEL FLOW
SHIFTING FROM THE NE. BUT AT THIS TIME DECIDED TO STICK WITH MAV.
FLOW WILL NOT BE THAT STRONG AND A LAND BREEZE COULD PREVENT THIS
SCENARIO FROM HAPPENING TOO. EKDMOS ENSEMBLE GUIDANCE ALSO SHOWS A
MEAN IN THE MID TO UPPER 50S.
SO WITH THAT SAID, TEMPS TONIGHT WILL STILL BE A COUPLE OF DEGREES
ABOVE NORMAL ACROSS SOUTH FLORIDA WITH A WARMING TREND IN STORE FOR
THE UPCOMING WEEKEND AND INTO THE FIRST PART OF NEXT WEEK WHEN
MODELS GENERALLY AGREE ON HIGH PRESSURE ALOFT BUILDING FROM THE
SOUTHERN GULF OF MEXICO ACROSS CUBA AND INTO THE BAHAMAS, KEEPING
JET STREAM AND STORM TRACKS WELL TO OUR NORTH. GFS IS THE MOST
AGGRESSIVE OF THE MODELS BUILDING THE AFOREMENTIONED HIGH ALOFT BUT
THE MEAN OF THE ENSEMBLE IS STILL CONSISTENT WITH THE SCENARIO AND
SO IS THE ECMWF. BOTTOM LINE, THE ENSUING WARMING TREND WILL RESULT
IN OVERNIGHT LOWS RUNNING CLOSE TO 10 DEGREES ABOVE NORMAL BY LATE
IN THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK ALONG WITH
DAYTIME HIGHS RUNNING AROUND 5 DEGREES ABOVE NORMAL.
IT WILL REMAIN DRY FOR THE MOST PART THROUGH THE WEEKEND WITH A
SLIGHT CHANCE OF SHOWERS MAY BE COMING BACK INTO THE PICTURE BY THE
EARLY TO MIDDLE PART OF NEXT WEEK AS LOW LEVEL MOISTURE SLOWLY
RETURNS FROM THE SOUTH BUT NOT LOOKING TOO PROMISING AT THIS TIME.
MARINE...
A BRIEF SURGE IN WIND OF UP TO 15 TO 20 KNOTS TODAY OFF THE COAST
OF PALM BEACH FROM THE NORTH NORTHEAST WILL RESULT IN A SHORT
LIVED SURGE IN SEAS OF UP TO 6 FEET IN THE GULF STREAM. SO WILL
PUT UP A SMALL CRAFT SHOULD EXERCISE CAUTION FOR THOSE WATERS
TODAY. OTHERWISE WINDS AND SEAS WILL REMAIN BELOW 10 TO 15 KNOTS
AND BELOW 4 FEET INTO THE EARLY PART OF NEXT WEEK.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES TODAY WILL BE BELOW 35 PERCENT IN
AREAS NORTH OF ALLIGATOR ALLEY ACROSS NORTHERN COLLIER, HENDRY,
AND GLADES COUNTIES TODAY FOR CLOSE TO 4 HOURS. HOWEVER ERC VALUES
ACROSS THE AREA REMAIN TOO LOW FOR ANY RED FLAG CONCERNS. AFTER
TODAY, LOW LEVEL MOISTURE WILL BE ON THE INCREASE AND SO NO OTHER
FIRE CONCERNS AT THIS TIME INTO EARLY NEXT WEEK AT THE VERY LEAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 55 76 61 / - - - -
FORT LAUDERDALE 75 61 77 66 / - - - -
MIAMI 76 60 77 65 / - - - -
NAPLES 73 52 78 57 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...47/RGH
AREA FORECAST DISCUSSION
NWS MIAMI FL
546 AM EST THU JAN 19 2012
.AVIATION...WEAKENING COLD FRNT APRCHG LK OKEE AREA AND WL MOV
INTO S FLA AND MOV OFF OF THE SE COAST ARND 15Z. MVFR CIGS WITH
LCL IFR OCCURRING AHD OF FRNT. MVFR CIGS PSBL E COAST TERMINALS
11Z-14Z THEN VFR ALL TERMINALS THRU THE END OF THE PD. SFC WNDS
NNW-N < 10 KTS BCMG NNE ALL TERMINALS AFT 18Z AND INCRG 10 TO 15
KTS THEN DCRG < 10 KTS AFT 00Z. POTENTIAL EXISTS THAT AN OFSHR
WND FLOW MAY DVLP LATE TONIGHT BUT NOT IN TAFS ATTM.
&&
.PREV DISCUSSION... /ISSUED 324 AM EST THU JAN 19 2012/
DISCUSSION...
LATEST DEW POINT SURFACE ANALYSIS REVEALS LEADING EDGE OF WEAK
FRONTAL BOUNDARY CURRENTLY ACROSS SOUTH CENTRAL FLORIDA BETWEEN
ORLANDO AND LAKE OKEECHOBEE. ANALYSIS OF MODEL GUIDANCE TRACKING THIS
FEATURE INDICATES THE BOUNDARY WILL BE ACROSS SOUTH FLORIDA BY
LATE MORNING AND/OR EARLY AFTERNOON. GLOBAL MODELS IN FACT BRING
IT THROUGH THE AREA BUT THE HIRES MODELS INCLUDING NCEP HIRES NMM
AND ARW AS WELL AS THE LOCAL WRF AND THE RUC INDICATE THE BOUNDARY
WILL SIMPLY DISSIPATE ACROSS THE AREA AS IT MOVES INTO SOUTH
FLORIDA TODAY. EITHER WAY DRIER AIR WILL BE MOVING INTO THE AREA
WITH IT. AHEAD OF IT, RADAR AND SATELLITE INDICATED SOME
CONVECTION EARLIER THIS MORNING MOVING INTO THE GULF WATERS BUT
IT HAS DISSIPATED SINCE THEN AS LOW LEVEL FORCING WITH THE FRONT
WEAKENS AND AS IT MOVES FARTHER AWAY FROM UPPER LEVEL DYNAMICS
WELL REMOVED TO THE NORTH. SO FAR LOOKS LIKE CLOUDS ASSOCIATED
WITH THE APPROACHING BOUNDARY ARE PREVENTING PATCHY FOG FROM
DEVELOPING THIS MORNING ACROSS INTERIOR AREAS OF SOUTH FLORIDA AND
THAT IS LIKELY TO REMAIN LIKE THAT BUT WILL CONTINUE TO MONITOR
JUST IN CASE. FOR THE MOMENT GIVEN TRENDS LEFT THAT OUT OF THE
FORECAST FOR THIS MORNING.
AHEAD OF THE BOUNDARY TODAY THERE WILL BE ONLY A SLIGHT CHANCE OF A
SHOWER, BEST OVER THE COASTAL WATERS, WITH DRIER AIR MASS
GRADUALLY MOVING IN PARTICULARLY BEGINNING AROUND MID TO LATE
MORNING AND INTO THE EARLY AFTERNOON. YET RAIN CHANCES NOT ENOUGH
TO MENTION IN THE FORECAST. AS ALLUDED TO ABOVE, THE BOUNDARY IS
EXPECTED TO STALL AND DISSIPATE BETWEEN MAINLAND SOUTH FLORIDA AND
THE STRAITS THROUGH TONIGHT. TEMPERATURES WILL CONTINUE TO BE WARM
WITH HIGHS IN THE 70S TODAY...AND THEN INTO THE UPPER 70S TO THE
LOWER 80S BY FRIDAY AND INTO THE WEEKEND. WITH THE DRIER AIR AND
EXCELLENT RADIATIONAL COOLING...OVERNIGHT LOWS TONIGHT MAY GET
INTO THE MID 40S ACROSS THE NORTHWEST INTERIOR. ALSO WITH LIGHT
WINDS AND LOW LEVEL FLOW TURNING FROM THE NORTHEAST, IT IS
POSSIBLE THAT PATCHY FOG DEVELOPS INLAND AROUND LAKE OKEECHOBEE
TONIGHT AND AGAIN FRIDAY NIGHT. HOWEVER, CHANCES OF THAT ARE BEST
FRIDAY NIGHT AS BY THEN RETURN FLOW FROM THE ATLANTIC WOULD HAVE
HAD MORE TIME TO MOISTEN UP THE LOW LEVELS A BIT. BUT GIVEN ALL
MOS GUIDANCE DEVELOP IT TONIGHT ALSO, I PUT IT IN THE GRIDS.
OVERALL TONIGHT WILL BE THE COOLEST NIGHT OF THE COMING WEEK. A
CAVEAT HERE IS THAT THE MET GUIDANCE IS SIGNIFICANTLY WARMER THAN
THE MAV FOR NORTHEAST PORTIONS OF THE AREA (PALM BEACH COUNTY). NAM
IS BANKING ON LOT OF CLOUDS RETURNING QUICKLY WITH LOW LEVEL FLOW
SHIFTING FROM THE NE. BUT AT THIS TIME DECIDED TO STICK WITH MAV.
FLOW WILL NOT BE THAT STRONG AND A LAND BREEZE COULD PREVENT THIS
SCENARIO FROM HAPPENING TOO. EKDMOS ENSEMBLE GUIDANCE ALSO SHOWS A
MEAN IN THE MID TO UPPER 50S.
SO WITH THAT SAID, TEMPS TONIGHT WILL STILL BE A COUPLE OF DEGREES
ABOVE NORMAL ACROSS SOUTH FLORIDA WITH A WARMING TREND IN STORE FOR
THE UPCOMING WEEKEND AND INTO THE FIRST PART OF NEXT WEEK WHEN
MODELS GENERALLY AGREE ON HIGH PRESSURE ALOFT BUILDING FROM THE
SOUTHERN GULF OF MEXICO ACROSS CUBA AND INTO THE BAHAMAS, KEEPING
JET STREAM AND STORM TRACKS WELL TO OUR NORTH. GFS IS THE MOST
AGGRESSIVE OF THE MODELS BUILDING THE AFOREMENTIONED HIGH ALOFT BUT
THE MEAN OF THE ENSEMBLE IS STILL CONSISTENT WITH THE SCENARIO AND
SO IS THE ECMWF. BOTTOM LINE, THE ENSUING WARMING TREND WILL RESULT
IN OVERNIGHT LOWS RUNNING CLOSE TO 10 DEGREES ABOVE NORMAL BY LATE
IN THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK ALONG WITH
DAYTIME HIGHS RUNNING AROUND 5 DEGREES ABOVE NORMAL.
IT WILL REMAIN DRY FOR THE MOST PART THROUGH THE WEEKEND WITH A
SLIGHT CHANCE OF SHOWERS MAY BE COMING BACK INTO THE PICTURE BY THE
EARLY TO MIDDLE PART OF NEXT WEEK AS LOW LEVEL MOISTURE SLOWLY
RETURNS FROM THE SOUTH BUT NOT LOOKING TOO PROMISING AT THIS TIME.
MARINE...
A BRIEF SURGE IN WIND OF UP TO 15 TO 20 KNOTS TODAY OFF THE COAST
OF PALM BEACH FROM THE NORTH NORTHEAST WILL RESULT IN A SHORT
LIVED SURGE IN SEAS OF UP TO 6 FEET IN THE GULF STREAM. SO WILL
PUT UP A SMALL CRAFT SHOULD EXERCISE CAUTION FOR THOSE WATERS
TODAY. OTHERWISE WINDS AND SEAS WILL REMAIN BELOW 10 TO 15 KNOTS
AND BELOW 4 FEET INTO THE EARLY PART OF NEXT WEEK.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES TODAY WILL BE BELOW 35 PERCENT IN
AREAS NORTH OF ALLIGATOR ALLEY ACROSS NORTHERN COLLIER, HENDRY,
AND GLADES COUNTIES TODAY FOR CLOSE TO 4 HOURS. HOWEVER ERC VALUES
ACROSS THE AREA REMAIN TOO LOW FOR ANY RED FLAG CONCERNS. AFTER
TODAY, LOW LEVEL MOISTURE WILL BE ON THE INCREASE AND SO NO OTHER
FIRE CONCERNS AT THIS TIME INTO EARLY NEXT WEEK AT THE VERY LEAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 55 76 61 / - - - -
FORT LAUDERDALE 75 61 77 66 / - - - -
MIAMI 76 60 77 65 / - - - -
NAPLES 73 52 78 57 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...52/PS
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION..CORRECTED
NWS MIAMI FL
324 AM EST THU JAN 19 2012
CORRECTION TO THIRD PARAGRAPH.
.DISCUSSION...
LATEST DEW POINT SURFACE ANALYSIS REVEALS LEADING EDGE OF WEAK
FRONTAL BOUNDARY CURRENTLY ACROSS SOUTH CENTRAL FLORIDA BETWEEN
ORLANDO AND LAKE OKEECHOBEE. ANALYSIS OF MODEL GUIDANCE TRACKING THIS
FEATURE INDICATES THE BOUNDARY WILL BE ACROSS SOUTH FLORIDA BY
LATE MORNING AND/OR EARLY AFTERNOON. GLOBAL MODELS IN FACT BRING
IT THROUGH THE AREA BUT THE HIRES MODELS INCLUDING NCEP HIRES NMM
AND ARW AS WELL AS THE LOCAL WRF AND THE RUC INDICATE THE BOUNDARY
WILL SIMPLY DISSIPATE ACROSS THE AREA AS IT MOVES INTO SOUTH
FLORIDA TODAY. EITHER WAY DRIER AIR WILL BE MOVING INTO THE AREA
WITH IT. AHEAD OF IT, RADAR AND SATELLITE INDICATED SOME
CONVECTION EARLIER THIS MORNING MOVING INTO THE GULF WATERS BUT
IT HAS DISSIPATED SINCE THEN AS LOW LEVEL FORCING WITH THE FRONT
WEAKENS AND AS IT MOVES FARTHER AWAY FROM UPPER LEVEL DYNAMICS
WELL REMOVED TO THE NORTH. SO FAR LOOKS LIKE CLOUDS ASSOCIATED
WITH THE APPROACHING BOUNDARY ARE PREVENTING PATCHY FOG FROM
DEVELOPING THIS MORNING ACROSS INTERIOR AREAS OF SOUTH FLORIDA AND
THAT IS LIKELY TO REMAIN LIKE THAT BUT WILL CONTINUE TO MONITOR
JUST IN CASE. FOR THE MOMENT GIVEN TRENDS LEFT THAT OUT OF THE
FORECAST FOR THIS MORNING.
AHEAD OF THE BOUNDARY TODAY THERE WILL BE ONLY A SLIGHT CHANCE OF A
SHOWER, BEST OVER THE COASTAL WATERS, WITH DRIER AIR MASS
GRADUALLY MOVING IN PARTICULARLY BEGINNING AROUND MID TO LATE
MORNING AND INTO THE EARLY AFTERNOON. YET RAIN CHANCES NOT ENOUGH
TO MENTION IN THE FORECAST. AS ALLUDED TO ABOVE, THE BOUNDARY IS
EXPECTED TO STALL AND DISSIPATE BETWEEN MAINLAND SOUTH FLORIDA AND
THE STRAITS THROUGH TONIGHT. TEMPERATURES WILL CONTINUE TO BE WARM
WITH HIGHS IN THE 70S TODAY...AND THEN INTO THE UPPER 70S TO THE
LOWER 80S BY FRIDAY AND INTO THE WEEKEND. WITH THE DRIER AIR AND
EXCELLENT RADIATIONAL COOLING...OVERNIGHT LOWS TONIGHT MAY GET
INTO THE MID 40S ACROSS THE NORTHWEST INTERIOR. ALSO WITH LIGHT
WINDS AND LOW LEVEL FLOW TURNING FROM THE NORTHEAST, IT IS
POSSIBLE THAT PATCHY FOG DEVELOPS INLAND AROUND LAKE OKEECHOBEE
TONIGHT AND AGAIN FRIDAY NIGHT. HOWEVER, CHANCES OF THAT ARE BEST
FRIDAY NIGHT AS BY THEN RETURN FLOW FROM THE ATLANTIC WOULD HAVE
HAD MORE TIME TO MOISTEN UP THE LOW LEVELS A BIT. BUT GIVEN ALL
MOS GUIDANCE DEVELOP IT TONIGHT ALSO, I PUT IT IN THE GRIDS.
OVERALL TONIGHT WILL BE THE COOLEST NIGHT OF THE COMING WEEK. A
CAVEAT HERE IS THAT THE MET GUIDANCE IS SIGNIFICANTLY WARMER THAN
THE MAV FOR NORTHEAST PORTIONS OF THE AREA (PALM BEACH COUNTY). NAM
IS BANKING ON LOT OF CLOUDS RETURNING QUICKLY WITH LOW LEVEL FLOW
SHIFTING FROM THE NE. BUT AT THIS TIME DECIDED TO STICK WITH MAV.
FLOW WILL NOT BE THAT STRONG AND A LAND BREEZE COULD PREVENT THIS
SCENARIO FROM HAPPENING TOO. EKDMOS ENSEMBLE GUIDANCE ALSO SHOWS A
MEAN IN THE MID TO UPPER 50S.
SO WITH THAT SAID, TEMPS TONIGHT WILL STILL BE A COUPLE OF DEGREES
ABOVE NORMAL ACROSS SOUTH FLORIDA WITH A WARMING TREND IN STORE FOR
THE UPCOMING WEEKEND AND INTO THE FIRST PART OF NEXT WEEK WHEN
MODELS GENERALLY AGREE ON HIGH PRESSURE ALOFT BUILDING FROM THE
SOUTHERN GULF OF MEXICO ACROSS CUBA AND INTO THE BAHAMAS, KEEPING
JET STREAM AND STORM TRACKS WELL TO OUR NORTH. GFS IS THE MOST
AGGRESSIVE OF THE MODELS BUILDING THE AFOREMENTIONED HIGH ALOFT BUT
THE MEAN OF THE ENSEMBLE IS STILL CONSISTENT WITH THE SCENARIO AND
SO IS THE ECMWF. BOTTOM LINE, THE ENSUING WARMING TREND WILL RESULT
IN OVERNIGHT LOWS RUNNING CLOSE TO 10 DEGREES ABOVE NORMAL BY LATE
IN THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK ALONG WITH
DAYTIME HIGHS RUNNING AROUND 5 DEGREES ABOVE NORMAL.
IT WILL REMAIN DRY FOR THE MOST PART THROUGH THE WEEKEND WITH A
SLIGHT CHANCE OF SHOWERS MAY BE COMING BACK INTO THE PICTURE BY THE
EARLY TO MIDDLE PART OF NEXT WEEK AS LOW LEVEL MOISTURE SLOWLY
RETURNS FROM THE SOUTH BUT NOT LOOKING TOO PROMISING AT THIS TIME.
&&
.MARINE...
A BRIEF SURGE IN WIND OF UP TO 15 TO 20 KNOTS TODAY OFF THE COAST
OF PALM BEACH FROM THE NORTH NORTHEAST WILL RESULT IN A SHORT
LIVED SURGE IN SEAS OF UP TO 6 FEET IN THE GULF STREAM. SO WILL
PUT UP A SMALL CRAFT SHOULD EXERCISE CAUTION FOR THOSE WATERS
TODAY. OTHERWISE WINDS AND SEAS WILL REMAIN BELOW 10 TO 15 KNOTS
AND BELOW 4 FEET INTO THE EARLY PART OF NEXT WEEK.
&&
.FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES TODAY WILL BE BELOW 35 PERCENT IN
AREAS NORTH OF ALLIGATOR ALLEY ACROSS NORTHERN COLLIER, HENDRY,
AND GLADES COUNTIES TODAY FOR CLOSE TO 4 HOURS. HOWEVER ERC VALUES
ACROSS THE AREA REMAIN TOO LOW FOR ANY RED FLAG CONCERNS. AFTER
TODAY, LOW LEVEL MOISTURE WILL BE ON THE INCREASE AND SO NO OTHER
FIRE CONCERNS AT THIS TIME INTO EARLY NEXT WEEK AT THE VERY LEAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 55 76 61 / - - - -
FORT LAUDERDALE 75 61 77 66 / - - - -
MIAMI 76 60 77 65 / - - - -
NAPLES 73 52 78 57 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...52/PS
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
938 PM CST FRI JAN 20 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
//PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SNOW NEARLY OVER AT 03Z...WITH VFR VSBY AND MVFR CIGS
CONTINUING.
* POTENTIAL FOR LAKE-INDUCED SNOW SHOWERS AT TIMES THROUGH
SATURDAY MORNING.
RATZER
//DISCUSSION...UPDATED 00Z...
SNOW BEGINNING TO WIND DOWN FROM THE WEST/NORTHWEST CURRENTLY...
WITH RADAR INDICATING HIGHER REFLECTIVITY IN HEAVIER SNOW NOW
SOUTH OF KORD. VISIBILITY INCREASING BETTER THAN A MILE GENERALLY
NORTHWEST OF A VYS-DPA-ORD LINE AND THIS SHOULD WORK INTO THE
CHICAGO AREA TERMINALS IN THE NEXT 2-3 HOURS. KMDW AND KGYY STILL
EXPECTED TO SEE SOME 1/2SM TO 1/4SM VIS EARLY...THOUGH MODELS
DEPICT RELATIVELY RAPID LOSS OF STRONGER LIFT BEYOND 00-02Z.
OUTSIDE OF THE HEAVIER SNOW...CEILINGS GENERALLY MVFR...SO SHOULD
SEE FAIRLY RAPID IMPROVEMENT FROM LIFR/IFR CONDITIONS THROUGH
EARLY THIS EVENING.
OTHER CONCERN IS LAKE-INDUCED SNOW SHOWERS WHICH CURRENTLY CAN BE
SEEN ON RADAR IN A LITTLE CONVERGENT BAND OFF KUGN. HIGH RES
MODELS INCLUDING RECENT RUC/HRRR RUNS INDICATE THIS CONVERGENT
BAND WILL EVENTUALLY SPREAD SOUTHEAST INTO THE PWK/ORD/DPA AREAS
DURING THE LATER OVERNIGHT HOURS...AND MAY IMPACT SOME OF THE
CHICAGO TAF SITES WITH SOME LIGHT SNOW THROUGH SATURDAY MORNING
BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE AFTERNOON. FORECAST
SOUNDINGS DEPICT POTENTIAL FOR RELATIVELY SHALLOW LAKE CONVECTION
SO NOT EXPECTING SIGNIFICANT ACCUMULATIONS OR VIS REDUCTIONS...
BUT WILL HAVE TO MONITOR. AND OF COURSE...EXACT PLACEMENT OF
NARROW BAND DIFFICULT AT THIS TIME.
WINDS...GENERALLY NORTHEAST THROUGH MIDDAY SATURDAY THOUGH THERE
MAY BE A LITTLE VARIABILITY BETWEEN ENE AND NNE THIS EVENING WITH
WEAK INVERTED TROUGH ALONG THE WEST SHORE OF LAKE MICHIGAN.
SURFACE HIGH BUILDS ACROSS THE AREA BY EARLY SATURDAY AFTERNOON
RESULTING IN WINDS EVENTUALLY VEERING BACK TO ESE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN ENDING OF SNOW SHORTLY...AND MVFR/PATCHY VFR
CIGS REMAINDER OF EVENING.
* MEDIUM CONFIDENCE IN WIND TRENDS THIS EVENING.
* HIGH CONFIDENCE IN CONTINUED LAKE INDUCED SNOW SHOWERS OVER
NORTHEAST IL LATER TONIGHT/SATURDAY MORNING...BUT LOW CONFIDENCE
ON SPECIFIC TIMING AND PLACEMENT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014 UNTIL
MIDNIGHT SATURDAY.
WINTER WEATHER ADVISORY...ILZ020-ILZ021-ILZ022-ILZ023 UNTIL
MIDNIGHT SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL MIDNIGHT SATURDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
924 PM CST FRI JAN 20 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
&&
.PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MODERATE/HEAVY SNOW DIMINISHING EARLY THIS EVENING.
* MVFR VIS/CIG CONDITIONS IN LINGERING LIGHTER SNOW REMAINDER OF
EVENING HOURS.
* POTENTIAL FOR LAKE-INDUCED SNOW SHOWERS AT TIMES THROUGH
SATURDAY MORNING.
RATZER
//DISCUSSION...UPDATED 00Z...
SNOW BEGINNING TO WIND DOWN FROM THE WEST/NORTHWEST CURRENTLY...
WITH RADAR INDICATING HIGHER REFLECTIVITY IN HEAVIER SNOW NOW
SOUTH OF KORD. VISIBILITY INCREASING BETTER THAN A MILE GENERALLY
NORTHWEST OF A VYS-DPA-ORD LINE AND THIS SHOULD WORK INTO THE
CHICAGO AREA TERMINALS IN THE NEXT 2-3 HOURS. KMDW AND KGYY STILL
EXPECTED TO SEE SOME 1/2SM TO 1/4SM VIS EARLY...THOUGH MODELS
DEPICT RELATIVELY RAPID LOSS OF STRONGER LIFT BEYOND 00-02Z.
OUTSIDE OF THE HEAVIER SNOW...CEILINGS GENERALLY MVFR...SO SHOULD
SEE FAIRLY RAPID IMPROVEMENT FROM LIFR/IFR CONDITIONS THROUGH
EARLY THIS EVENING.
OTHER CONCERN IS LAKE-INDUCED SNOW SHOWERS WHICH CURRENTLY CAN BE
SEEN ON RADAR IN A LITTLE CONVERGENT BAND OFF KUGN. HIGH RES
MODELS INCLUDING RECENT RUC/HRRR RUNS INDICATE THIS CONVERGENT
BAND WILL EVENTUALLY SPREAD SOUTHEAST INTO THE PWK/ORD/DPA AREAS
DURING THE LATER OVERNIGHT HOURS...AND MAY IMPACT SOME OF THE
CHICAGO TAF SITES WITH SOME LIGHT SNOW THROUGH SATURDAY MORNING
BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE AFTERNOON. FORECAST
SOUNDINGS DEPICT POTENTIAL FOR RELATIVELY SHALLOW LAKE CONVECTION
SO NOT EXPECTING SIGNIFICANT ACCUMULATIONS OR VIS REDUCTIONS...
BUT WILL HAVE TO MONITOR. AND OF COURSE...EXACT PLACEMENT OF
NARROW BAND DIFFICULT AT THIS TIME.
WINDS...GENERALLY NORTHEAST THROUGH MIDDAY SATURDAY THOUGH THERE
MAY BE A LITTLE VARIABILITY BETWEEN ENE AND NNE THIS EVENING WITH
WEAK INVERTED TROUGH ALONG THE WEST SHORE OF LAKE MICHIGAN.
SURFACE HIGH BUILDS ACROSS THE AREA BY EARLY SATURDAY AFTERNOON
RESULTING IN WINDS EVENTUALLY VEERING BACK TO ESE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN LOSS OF LIFR/IFR AND IMPROVING TRENDS IN
VIS/CIG THIS EVENING.
* MEDIUM CONFIDENCE IN WIND TRENDS THIS EVENING.
* HIGH CONFIDENCE IN CONTINUED LAKE INDUCED SNOW SHOWERS OVER
NORTHEAST IL LATER TONIGHT/SATURDAY MORNING...BUT LOW CONFIDENCE
ON SPECIFIC TIMING AND PLACEMENT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL MIDNIGHT SATURDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
658 PM CST FRI JAN 20 2012
.DISCUSSION...UPDATED
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MODERATE/HEAVY SNOW DIMINISHING EARLY THIS EVENING.
* MVFR VIS/CIG CONDITIONS IN LINGERING LIGHTER SNOW REMAINDER OF
EVENING HOURS.
* POTENTIAL FOR LAKE-INDUCED SNOW SHOWERS AT TIMES THROUGH
SATURDAY MORNING.
RATZER
//DISCUSSION...UPDATED 00Z...
SNOW BEGINNING TO WIND DOWN FROM THE WEST/NORTHWEST CURRENTLY...
WITH RADAR INDICATING HIGHER REFLECTIVITY IN HEAVIER SNOW NOW
SOUTH OF KORD. VISIBILITY INCREASING BETTER THAN A MILE GENERALLY
NORTHWEST OF A VYS-DPA-ORD LINE AND THIS SHOULD WORK INTO THE
CHICAGO AREA TERMINALS IN THE NEXT 2-3 HOURS. KMDW AND KGYY STILL
EXPECTED TO SEE SOME 1/2SM TO 1/4SM VIS EARLY...THOUGH MODELS
DEPICT RELATIVELY RAPID LOSS OF STRONGER LIFT BEYOND 00-02Z.
OUTSIDE OF THE HEAVIER SNOW...CEILINGS GENERALLY MVFR...SO SHOULD
SEE FAIRLY RAPID IMPROVEMENT FROM LIFR/IFR CONDITIONS THROUGH
EARLY THIS EVENING.
OTHER CONCERN IS LAKE-INDUCED SNOW SHOWERS WHICH CURRENTLY CAN BE
SEEN ON RADAR IN A LITTLE CONVERGENT BAND OFF KUGN. HIGH RES
MODELS INCLUDING RECENT RUC/HRRR RUNS INDICATE THIS CONVERGENT
BAND WILL EVENTUALLY SPREAD SOUTHEAST INTO THE PWK/ORD/DPA AREAS
DURING THE LATER OVERNIGHT HOURS...AND MAY IMPACT SOME OF THE
CHICAGO TAF SITES WITH SOME LIGHT SNOW THROUGH SATURDAY MORNING
BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE AFTERNOON. FORECAST
SOUNDINGS DEPICT POTENTIAL FOR RELATIVELY SHALLOW LAKE CONVECTION
SO NOT EXPECTING SIGNIFICANT ACCUMULATIONS OR VIS REDUCTIONS...
BUT WILL HAVE TO MONITOR. AND OF COURSE...EXACT PLACEMENT OF
NARROW BAND DIFFICULT AT THIS TIME.
WINDS...GENERALLY NORTHEAST THROUGH MIDDAY SATURDAY THOUGH THERE
MAY BE A LITTLE VARIABILITY BETWEEN ENE AND NNE THIS EVENING WITH
WEAK INVERTED TROUGH ALONG THE WEST SHORE OF LAKE MICHIGAN.
SURFACE HIGH BUILDS ACROSS THE AREA BY EARLY SATURDAY AFTERNOON
RESULTING IN WINDS EVENTUALLY VEERING BACK TO ESE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN LOSS OF LIFR/IFR AND IMPROVING TRENDS IN
VIS/CIG THIS EVENING.
* MEDIUM CONFIDENCE IN WIND TRENDS THIS EVENING.
* HIGH CONFIDENCE IN CONTINUED LAKE INDUCED SNOW SHOWERS OVER
NORTHEAST IL LATER TONIGHT/SATURDAY MORNING...BUT LOW CONFIDENCE
ON SPECIFIC TIMING AND PLACEMENT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL
9 PM FRIDAY.
WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014 UNTIL
MIDNIGHT SATURDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023
UNTIL MIDNIGHT SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL MIDNIGHT SATURDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
655 PM CST FRI JAN 20 2012
.DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST..DISCUSSION...
SHEA
.DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
.DISCUSSION FOR SATURDAY THROUGH FRIDAY...
335 PM CST...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
//PREV DISCUSSION...
1059 AM CST
LEVEL FGEN FORCING FARTHER TO THE NORTHEAST...BUT STILL DEALING WITH
SATURATING THE DRIER LOW LEVEL AIR. MAIN CONCERNS WITH THE FORECAST
FOR THIS AFTERNOON WILL BE DEALING WITH A SOUTHWARD TREND IN THE
MODELS FOR AXIS OF HEAVIEST QPF AND COMPLEX PHASING/INTERACTIONS
WITH SOUTHERN LOW PRESSURE SYSTEM. MOST GUIDANCE HAS TRENDED THE
AXIS OF HEAVIEST QPF SLIGHTLY FARTHER SOUTH...INTO PORTIONS OF
NORTHERN WILL COUNTY AND KENDALL COUNTY. GUIDANCE ALSO IN GOOD
AGREEMENT WITH OMEGAS PEAKING MID AFTERNOON INTO EARLY EVENING
WITH RATES OF AN INCH PER HOUR POSSIBLE DURING THIS
PERIOD...PARTICULARLY BETWEEN THE I-90 AND I-80 CORRIDORS. FOR
TOTAL SNOWFALL TODAY...DID MODERATE FORECAST SNOW RATIOS A
BIT...LOOKING AT AN AVERAGE OF 14-15:1 OVER SIX HOUR PERIOD THIS
AFTERNOON...BUT AT LEAST TEMPORARILY WE COULD BE LOOKING AT HIGHER
RATIOS FOR A SHORT WHILE. THIS WILL RESULT IN SNOW TOTALS OF 4 TO
7 INCHES PRETTY MUCH CENTERED DOWN THE I-88 CORRIDOR. WITH NO
MAJOR CHANGES TO GOING FORECAST...WILL NOT MAKE ANY ADJUSTMENTS TO
THE GOING WINTER WEATHER HEADLINES AT THIS TIME BUT DID SLIGHTLY
BUMP UP SNOW TOTALS SOUTH OF THE CURRENT WARNED AREA...EXPECTING
HIGHER END ADVISORY SNOWS ACROSS PORTIONS OF NORTHERN WILL COUNTY
AND KENDALL COUNTY...AS WELL AS LAKE AND PORTER COUNTIES IN
INDIANA. SECONDARY ISSUE WILL BE INTERACTIONS WITH A LOW PRESSURE
SYSTEM MOVING ACROSS THE MID MISSISSIPPI VALLEY LATER THIS
EVENING. GUIDANCE SUGGESTS THAT SOME OF THE STRONGER SYNOPTIC
FORCING AS NOTED BY Q-VECTOR CONVERGENCE WILL SHIFT FARTHER
SOUTH...WITH SOME GUIDANCE EVEN HINTING THAT HEAVIER SNOWS WILL
SHIFT ACROSS THE SOUTHERN PORTION OF THE CWA. BASED ON MODELS POOR
ABILITY TO HANDLE SUCH SITUATIONS...CONFIDENCE IS SOMEWHAT LOW ON
HOW THINGS MAY PLAY OUT THIS EVENING...AND WILL HAVE TO MONITOR
SHORT TERM TRENDS CLOSELY. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MODERATE/HEAVY SNOW DIMINISHING EARLY THIS EVENING.
* MVFR VIS/CIG CONDITIONS IN LINGERING LIGHTER SNOW REMAINDER OF
EVENING HOURS.
* POTENTIAL FOR LAKE-INDUCED SNOW SHOWERS AT TIMES THROUGH
SATURDAY MORNING.
RATZER
//DISCUSSION...UPDATED 00Z...
SNOW BEGINNING TO WIND DOWN FROM THE WEST/NORTHWEST CURRENTLY...
WITH RADAR INDICATING HIGHER REFLECTIVITY IN HEAVIER SNOW NOW
SOUTH OF KORD. VISIBILITY INCREASING BETTER THAN A MILE GENERALLY
NORTHWEST OF A VYS-DPA-ORD LINE AND THIS SHOULD WORK INTO THE
CHICAGO AREA TERMINALS IN THE NEXT 2-3 HOURS. KMDW AND KGYY STILL
EXPECTED TO SEE SOME 1/2SM TO 1/4SM VIS EARLY...THOUGH MODELS
DEPICT RELATIVELY RAPID LOSS OF STRONGER LIFT BEYOND 00-02Z.
OUTSIDE OF THE HEAVIER SNOW...CEILINGS GENERALLY MVFR...SO SHOULD
SEE FAIRLY RAPID IMPROVEMENT FROM LIFR/IFR CONDITIONS THROUGH
EARLY THIS EVENING.
OTHER CONCERN IS LAKE-INDUCED SNOW SHOWERS WHICH CURRENTLY CAN BE
SEEN ON RADAR IN A LITTLE CONVERGENT BAND OFF KUGN. HIGH RES
MODELS INCLUDING RECENT RUC/HRRR RUNS INDICATE THIS CONVERGENT
BAND WILL EVENTUALLY SPREAD SOUTHEAST INTO THE PWK/ORD/DPA AREAS
DURING THE LATER OVERNIGHT HOURS...AND MAY IMPACT SOME OF THE
CHICAGO TAF SITES WITH SOME LIGHT SNOW THROUGH SATURDAY MORNING
BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE AFTERNOON. FORECAST
SOUNDINGS DEPICT POTENTIAL FOR RELATIVELY SHALLOW LAKE CONVECTION
SO NOT EXPECTING SIGNIFICANT ACCUMULATIONS OR VIS REDUCTIONS...
BUT WILL HAVE TO MONITOR. AND OF COURSE...EXACT PLACEMENT OF
NARROW BAND DIFFICULT AT THIS TIME.
WINDS...GENERALLY NORTHEAST THROUGH MIDDAY SATURDAY THOUGH THERE
MAY BE A LITTLE VARIABILITY BETWEEN ENE AND NNE THIS EVENING WITH
WEAK INVERTED TROUGH ALONG THE WEST SHORE OF LAKE MICHIGAN.
SURFACE HIGH BUILDS ACROSS THE AREA BY EARLY SATURDAY AFTERNOON
RESULTING IN WINDS EVENTUALLY VEERING BACK TO ESE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN LOSS OF LIFR/IFR AND IMPROVING TRENDS IN
VIS/CIG THIS EVENING.
* MEDIUM CONFIDENCE IN WIND TRENDS THIS EVENING.
* HIGH CONFIDENCE IN CONTINUED LAKE INDUCED SNOW SHOWERS OVER
NORTHEAST IL LATER TONIGHT/SATURDAY MORNING...BUT LOW CONFIDENCE
ON SPECIFIC TIMING AND PLACEMENT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL
9 PM FRIDAY.
WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014 UNTIL
MIDNIGHT SATURDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023
UNTIL MIDNIGHT SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL MIDNIGHT SATURDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1142 AM CST THU JAN 19 2012
.DISCUSSION...
ISSUED 1023 AM CST THU JAN 19 2012
BAND OF LIGHT SNOW THAT IMPACTED NORTH-CENTRAL ILLINOIS EARLY THIS
MORNING IS QUICKLY PUSHING OFF TO THE EAST. 16Z RADAR IMAGERY/SURFACE
OBS SHOW LIGHT SNOW PERSISTING ACROSS ONLY THE FAR NORTHERN KILX
CWA...WITH MOSTLY CLOUDY AND DRY CONDITIONS ELSEWHERE. BASED ON
TRENDS...HAVE UPDATED THE FORECAST TO REMOVE MENTION OF SNOW
EVERYWHERE EXCEPT ALONG/NORTHEAST OF THE I-74 CORRIDOR WHERE IT
WILL CONTINUE FOR THE NEXT COUPLE OF HOURS. NOT EXPECTING MUCH
ADDITIONAL ACCUMULATION...WITH STORM TOTAL AMOUNTS OF AROUND 1
INCH NORTH OF A GALESBURG TO LEXINGTON LINE. ONCE THE SNOW
ENDS...A MOSTLY CLOUDY AND COLD AFTERNOON WILL TAKE SHAPE ACROSS
THE ENTIRE AREA. TEMPERATURES WILL RISE A FEW MORE DEGREES INTO
THE MIDDLE TO UPPER 30S ALONG/SOUTH OF I-70 BY MIDDAY...THEN
READINGS WILL DROP INTO THE 20S THIS AFTERNOON. ELSEWHERE...TEMPS
WILL REMAIN NEARLY STEADY OR SLOWLY FALL INTO THE TEENS.
&&
.AVIATION...
ISSUED 1142 AM CST THU JAN 19 2012
LIGHT SNOW AND LOW CEILINGS AROUND 2500FT WILL CONTINUE TO IMPACT
BOTH KPIA AND KBMI UNTIL 19/20Z...BEFORE THE PRECIP GRADUALLY
SHIFTS OFF TO THE EAST. MEANWHILE...A MID-LEVEL CLOUD DECK WILL
PREVAIL AT THE REMAINING TERMINALS. SATELLITE IMAGERY SHOWS CLOUD
COVER CLEARING OUT ACROSS CENTRAL IOWA...AND BASED ON TIMING TOOLS
AND NAM RH PROFILES...IT APPEARS SKIES WILL CLEAR FROM WEST TO
EAST ACROSS CENTRAL ILLINOIS BETWEEN 21Z AND 23Z. MOSTLY CLEAR
SKIES WILL THEN PREVAIL THROUGH THE EVENING...BEFORE CLOUDS ONCE
AGAIN BEGIN TO INCREASE LATE TONIGHT INTO FRIDAY MORNING. FORECAST
SOUNDINGS AND TIME-HEIGHT CROSS-SECTIONS SUGGEST CEILINGS
LOWERING TO AROUND 1500FT BETWEEN 15Z AND 17Z. SINCE SOUNDINGS DO
NOT FULLY SATURATE AND LIFT REMAINS WEAK...THINK ANY LIGHT PRECIP
WILL HOLD OFF UNTIL FRIDAY AFTERNOON. WINDS WILL INITIALLY BE FROM
THE N/NW AT 10 TO 15KT TODAY...THEN WILL VEER TO EASTERLY AT
AROUND 10KT BY FRIDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 245 AM CST THU JAN 19 2012
SHARP ARCTIC COLD FRONT IS ABOUT TO MOVE INTO THE NORTHWEST TIP OF
THE CWA AT 08Z...OVERALL EXTENDING FROM EAST CENTRAL WISCONSIN TO
AROUND KANSAS CITY. TEMPERATURES QUICKLY DROP OFF INTO THE SINGLE
DIGITS AS CLOSE AS CENTRAL IOWA. AREA OF LIGHT SNOW SO FAR HAS
MAINLY BEEN BEHIND THE FRONT. UPSTAIRS...VERY TIGHT UPPER FLOW
CONTINUES...WITH EVENING UPPER AIR ANALYSIS SHOWING A SCREAMING
150+ KNOT JET AT 300 MB FROM AROUND SEATTLE SOUTHEAST INTO
MISSOURI.
MAIN FORECAST CHALLENGE WITH THIS PACKAGE IS WITH PRECIPITATION
TYPES FRIDAY AND FRIDAY NIGHT. THE EFFECTS OF THE CURRENT SYSTEM
ARE A SECONDARY CONCERN.
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
LATEST HRRR MODEL SWEEPS THE FRONT ACROSS THE CWA THIS MORNING...
LINGERING THROUGH MIDDAY ACROSS THE FAR SOUTHEAST. BEST LIFT WITH
THIS FRONT IS STILL EXPECTED OVER THE NORTHEAST THIRD OF THE
CWA...WITH 1-2 INCHES OF SNOW EXPECTED NORTH OF A BLOOMINGTON TO
DANVILLE LINE THROUGH EARLY AFTERNOON. SHARP SOUTHERN CUTOFF TO
THE SNOW IS EXPECTED...AND WENT WITH ONLY SLIGHT CHANCES SOUTH OF
A JACKSONVILLE TO TERRE HAUTE LINE. ONLY THE SOUTHEAST CWA IS
EXPECTED TO SEE TEMPERATURES RISE ABOVE FREEZING...WITH MOST OF
THE FORECAST AREA SEEING FALLING DAYTIME TEMPERATURES.
THE FRIDAY STORM SYSTEM CONTINUES TO HAVE SEPARATE CONCERNS...ONE
WITH THE SNOW ACROSS THE NORTH IN THE STRONGER LIFT AND BAROCLINIC
ZONE...AND THE POTENTIAL FOR MIXED PRECIPITATION FURTHER SOUTH
CLOSER TO THE SURFACE FEATURES. SNOW-WISE...BEST LIFT STILL
EXPECTED JUST TO OUR NORTH ACROSS NORTHERN ILLINOIS...BUT 2-3
INCHES IS LIKELY AS FAR SOUTH AS GALESBURG AND PEORIA FRIDAY INTO
FRIDAY EVENING. FURTHER SOUTH...FORECAST SOUNDINGS SHOWING A
WEDGE OF WARM AIR AROUND 900 MB MOVING IN LATER FRIDAY AFTERNOON
AND ESPECIALLY DURING THE EVENING. THE NAM IS MOST PRONOUNCED WITH
THIS AROUND CHAMPAIGN AND MATTOON...WHILE THE GFS IS FURTHER SOUTH
TOWARD LAWRENCEVILLE AND THE LOCAL WRF IN BETWEEN. EVAPORATIVE
COOLING WOULD FAVOR MORE OF A SLEET/SNOW MIXTURE INITIALLY...THEN
SOME FREEZING RAIN AND SLEET IN THE EVENING BEFORE SWITCHING OVER
TO SNOW LATE TONIGHT. WILL INCLUDE SOME LOW ICE ACCUMULATIONS IN
AREAS MAINLY BETWEEN I-72 AND I-70...WITH LOCATIONS FROM MATTOON
TO PARIS WITH THE HIGHEST AMOUNTS OF AROUND 0.05 INCH OR SO. MAY
NEED TO CONSIDER WINTER WEATHER ADVISORIES IN SOME PARTS OF THE
CWA...BUT ENOUGH MODEL VARIABILITY EXISTS TO PRECLUDE ISSUING ONE
AT THIS TIME.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
PRECIPITATION TO BE OUT OF THE AREA BEFORE SUNRISE SATURDAY...WITH
HIGH PRESSURE RESULTING IN DRY WEATHER. FOCUS IN THE LONGER TERM
SHIFTS TO A DIGGING SHORTWAVE WHICH WILL CROSS THE MIDDLE OF THE
NATION SUNDAY NIGHT AND MONDAY. FOLLOWED THE SLOWER ECMWF/CANADIAN
SOLUTIONS...WHICH FAVOR RAIN FOR THE MOST PART AND A CHANGEOVER TO
SNOW AS THE PRECIPITATION ENDS SUNDAY NIGHT. MODEL SOLUTIONS ARE
CLOSER TO EACH OTHER ON THE NEXT WAVE WHICH CROSSES MIDWEEK...WITH
THE NEXT SHOT OF PRECIPITATION.
ASIDE FROM THE COLD START TO THE WEEKEND...TEMPERATURES MUCH OF
THIS PERIOD WILL BE SEVERAL DEGREES ABOVE NORMAL.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1023 AM CST THU JAN 19 2012
.DISCUSSION...
ISSUED 1023 AM CST THU JAN 19 2012
BAND OF LIGHT SNOW THAT IMPACTED NORTH-CENTRAL ILLINOIS EARLY THIS
MORNING IS QUICKLY PUSHING OFF TO THE EAST. 16Z RADAR IMAGERY/SURFACE
OBS SHOW LIGHT SNOW PERSISTING ACROSS ONLY THE FAR NORTHERN KILX
CWA...WITH MOSTLY CLOUDY AND DRY CONDITIONS ELSEWHERE. BASED ON
TRENDS...HAVE UPDATED THE FORECAST TO REMOVE MENTION OF SNOW
EVERYWHERE EXCEPT ALONG/NORTHEAST OF THE I-74 CORRIDOR WHERE IT
WILL CONTINUE FOR THE NEXT COUPLE OF HOURS. NOT EXPECTING MUCH
ADDITIONAL ACCUMULATION...WITH STORM TOTAL AMOUNTS OF AROUND 1
INCH NORTH OF A GALESBURG TO LEXINGTON LINE. ONCE THE SNOW
ENDS...A MOSTLY CLOUDY AND COLD AFTERNOON WILL TAKE SHAPE ACROSS
THE ENTIRE AREA. TEMPERATURES WILL RISE A FEW MORE DEGREES INTO
THE MIDDLE TO UPPER 30S ALONG/SOUTH OF I-70 BY MIDDAY...THEN
READINGS WILL DROP INTO THE 20S THIS AFTERNOON. ELSEWHERE...TEMPS
WILL REMAIN NEARLY STEADY OR SLOWLY FALL INTO THE TEENS.
BARNES
&&
.AVIATION...
ISSUED 543 AM CST THU JAN 19 2012
CONDITIONS WILL BE PRIMARILY VFR AT ALL TAF SITES THROUGH THE
PERIOD. A QUICK MOVING WINTER SYSTEM WILL BRING TEMPO SNOW/MVFR
CIGS/VIS TO PIA/BMI/CMI THIS MORNING THROUGH ABOUT NOON...WHILE
SPI/DEC JUST WILL HAVE VCSH AND SCATTERED AT 2.5KFT. ONCE SYSTEM
PASSES CLOUDS HEIGHTS WILL RISE AGAIN AND WILL BE LEFT WITH JUST
CIRRUS CLOUDS FROM THIS AFTERNOON THROUGH TONIGHT. WINDS WILL BE
SOUTHWEST AHEAD OF THE FRONT BUT QUICKLY SWITCH TO NORTHWEST
BEHIND THE FRONT. EXPECT NORTHERLY WINDS THIS AFTERNOON THROUGH
THIS EVENING...BECOMING NORTHEAST OVERNIGHT. TIGHT TEMP GRADIENT
BEHIND FRONT WILL BRING SOME STRONGER WINDS...BUT GRADIENT WEAKENS
A FEW HOURS BEHIND THE FRONT SO WINDS WILL DECREASE REST OF THE
PERIOD.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 245 AM CST THU JAN 19 2012
SHARP ARCTIC COLD FRONT IS ABOUT TO MOVE INTO THE NORTHWEST TIP OF
THE CWA AT 08Z...OVERALL EXTENDING FROM EAST CENTRAL WISCONSIN TO
AROUND KANSAS CITY. TEMPERATURES QUICKLY DROP OFF INTO THE SINGLE
DIGITS AS CLOSE AS CENTRAL IOWA. AREA OF LIGHT SNOW SO FAR HAS
MAINLY BEEN BEHIND THE FRONT. UPSTAIRS...VERY TIGHT UPPER FLOW
CONTINUES...WITH EVENING UPPER AIR ANALYSIS SHOWING A SCREAMING
150+ KNOT JET AT 300 MB FROM AROUND SEATTLE SOUTHEAST INTO
MISSOURI.
MAIN FORECAST CHALLENGE WITH THIS PACKAGE IS WITH PRECIPITATION
TYPES FRIDAY AND FRIDAY NIGHT. THE EFFECTS OF THE CURRENT SYSTEM
ARE A SECONDARY CONCERN.
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
LATEST HRRR MODEL SWEEPS THE FRONT ACROSS THE CWA THIS MORNING...
LINGERING THROUGH MIDDAY ACROSS THE FAR SOUTHEAST. BEST LIFT WITH
THIS FRONT IS STILL EXPECTED OVER THE NORTHEAST THIRD OF THE
CWA...WITH 1-2 INCHES OF SNOW EXPECTED NORTH OF A BLOOMINGTON TO
DANVILLE LINE THROUGH EARLY AFTERNOON. SHARP SOUTHERN CUTOFF TO
THE SNOW IS EXPECTED...AND WENT WITH ONLY SLIGHT CHANCES SOUTH OF
A JACKSONVILLE TO TERRE HAUTE LINE. ONLY THE SOUTHEAST CWA IS
EXPECTED TO SEE TEMPERATURES RISE ABOVE FREEZING...WITH MOST OF
THE FORECAST AREA SEEING FALLING DAYTIME TEMPERATURES.
THE FRIDAY STORM SYSTEM CONTINUES TO HAVE SEPARATE CONCERNS...ONE
WITH THE SNOW ACROSS THE NORTH IN THE STRONGER LIFT AND BAROCLINIC
ZONE...AND THE POTENTIAL FOR MIXED PRECIPITATION FURTHER SOUTH
CLOSER TO THE SURFACE FEATURES. SNOW-WISE...BEST LIFT STILL
EXPECTED JUST TO OUR NORTH ACROSS NORTHERN ILLINOIS...BUT 2-3
INCHES IS LIKELY AS FAR SOUTH AS GALESBURG AND PEORIA FRIDAY INTO
FRIDAY EVENING. FURTHER SOUTH...FORECAST SOUNDINGS SHOWING A
WEDGE OF WARM AIR AROUND 900 MB MOVING IN LATER FRIDAY AFTERNOON
AND ESPECIALLY DURING THE EVENING. THE NAM IS MOST PRONOUNCED WITH
THIS AROUND CHAMPAIGN AND MATTOON...WHILE THE GFS IS FURTHER SOUTH
TOWARD LAWRENCEVILLE AND THE LOCAL WRF IN BETWEEN. EVAPORATIVE
COOLING WOULD FAVOR MORE OF A SLEET/SNOW MIXTURE INITIALLY...THEN
SOME FREEZING RAIN AND SLEET IN THE EVENING BEFORE SWITCHING OVER
TO SNOW LATE TONIGHT. WILL INCLUDE SOME LOW ICE ACCUMULATIONS IN
AREAS MAINLY BETWEEN I-72 AND I-70...WITH LOCATIONS FROM MATTOON
TO PARIS WITH THE HIGHEST AMOUNTS OF AROUND 0.05 INCH OR SO. MAY
NEED TO CONSIDER WINTER WEATHER ADVISORIES IN SOME PARTS OF THE
CWA...BUT ENOUGH MODEL VARIABILITY EXISTS TO PRECLUDE ISSUING ONE
AT THIS TIME.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
PRECIPITATION TO BE OUT OF THE AREA BEFORE SUNRISE SATURDAY...WITH
HIGH PRESSURE RESULTING IN DRY WEATHER. FOCUS IN THE LONGER TERM
SHIFTS TO A DIGGING SHORTWAVE WHICH WILL CROSS THE MIDDLE OF THE
NATION SUNDAY NIGHT AND MONDAY. FOLLOWED THE SLOWER ECMWF/CANADIAN
SOLUTIONS...WHICH FAVOR RAIN FOR THE MOST PART AND A CHANGEOVER TO
SNOW AS THE PRECIPITATION ENDS SUNDAY NIGHT. MODEL SOLUTIONS ARE
CLOSER TO EACH OTHER ON THE NEXT WAVE WHICH CROSSES MIDWEEK...WITH
THE NEXT SHOT OF PRECIPITATION.
ASIDE FROM THE COLD START TO THE WEEKEND...TEMPERATURES MUCH OF
THIS PERIOD WILL BE SEVERAL DEGREES ABOVE NORMAL.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
543 AM CST THU JAN 19 2012
.DISCUSSION...
ISSUED 245 AM CST THU JAN 19 2012
SHARP ARCTIC COLD FRONT IS ABOUT TO MOVE INTO THE NORTHWEST TIP OF
THE CWA AT 08Z...OVERALL EXTENDING FROM EAST CENTRAL WISCONSIN TO
AROUND KANSAS CITY. TEMPERATURES QUICKLY DROP OFF INTO THE SINGLE
DIGITS AS CLOSE AS CENTRAL IOWA. AREA OF LIGHT SNOW SO FAR HAS
MAINLY BEEN BEHIND THE FRONT. UPSTAIRS...VERY TIGHT UPPER FLOW
CONTINUES...WITH EVENING UPPER AIR ANALYSIS SHOWING A SCREAMING
150+ KNOT JET AT 300 MB FROM AROUND SEATTLE SOUTHEAST INTO
MISSOURI.
MAIN FORECAST CHALLENGE WITH THIS PACKAGE IS WITH PRECIPITATION
TYPES FRIDAY AND FRIDAY NIGHT. THE EFFECTS OF THE CURRENT SYSTEM
ARE A SECONDARY CONCERN.
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
LATEST HRRR MODEL SWEEPS THE FRONT ACROSS THE CWA THIS MORNING...
LINGERING THROUGH MIDDAY ACROSS THE FAR SOUTHEAST. BEST LIFT WITH
THIS FRONT IS STILL EXPECTED OVER THE NORTHEAST THIRD OF THE
CWA...WITH 1-2 INCHES OF SNOW EXPECTED NORTH OF A BLOOMINGTON TO
DANVILLE LINE THROUGH EARLY AFTERNOON. SHARP SOUTHERN CUTOFF TO
THE SNOW IS EXPECTED...AND WENT WITH ONLY SLIGHT CHANCES SOUTH OF
A JACKSONVILLE TO TERRE HAUTE LINE. ONLY THE SOUTHEAST CWA IS
EXPECTED TO SEE TEMPERATURES RISE ABOVE FREEZING...WITH MOST OF
THE FORECAST AREA SEEING FALLING DAYTIME TEMPERATURES.
THE FRIDAY STORM SYSTEM CONTINUES TO HAVE SEPARATE CONCERNS...ONE
WITH THE SNOW ACROSS THE NORTH IN THE STRONGER LIFT AND BAROCLINIC
ZONE...AND THE POTENTIAL FOR MIXED PRECIPITATION FURTHER SOUTH
CLOSER TO THE SURFACE FEATURES. SNOW-WISE...BEST LIFT STILL
EXPECTED JUST TO OUR NORTH ACROSS NORTHERN ILLINOIS...BUT 2-3
INCHES IS LIKELY AS FAR SOUTH AS GALESBURG AND PEORIA FRIDAY INTO
FRIDAY EVENING. FURTHER SOUTH...FORECAST SOUNDINGS SHOWING A
WEDGE OF WARM AIR AROUND 900 MB MOVING IN LATER FRIDAY AFTERNOON
AND ESPECIALLY DURING THE EVENING. THE NAM IS MOST PRONOUNCED WITH
THIS AROUND CHAMPAIGN AND MATTOON...WHILE THE GFS IS FURTHER SOUTH
TOWARD LAWRENCEVILLE AND THE LOCAL WRF IN BETWEEN. EVAPORATIVE
COOLING WOULD FAVOR MORE OF A SLEET/SNOW MIXTURE INITIALLY...THEN
SOME FREEZING RAIN AND SLEET IN THE EVENING BEFORE SWITCHING OVER
TO SNOW LATE TONIGHT. WILL INCLUDE SOME LOW ICE ACCUMULATIONS IN
AREAS MAINLY BETWEEN I-72 AND I-70...WITH LOCATIONS FROM MATTOON
TO PARIS WITH THE HIGHEST AMOUNTS OF AROUND 0.05 INCH OR SO. MAY
NEED TO CONSIDER WINTER WEATHER ADVISORIES IN SOME PARTS OF THE
CWA...BUT ENOUGH MODEL VARIABILITY EXISTS TO PRECLUDE ISSUING ONE
AT THIS TIME.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
PRECIPITATION TO BE OUT OF THE AREA BEFORE SUNRISE SATURDAY...WITH
HIGH PRESSURE RESULTING IN DRY WEATHER. FOCUS IN THE LONGER TERM
SHIFTS TO A DIGGING SHORTWAVE WHICH WILL CROSS THE MIDDLE OF THE
NATION SUNDAY NIGHT AND MONDAY. FOLLOWED THE SLOWER ECMWF/CANADIAN
SOLUTIONS...WHICH FAVOR RAIN FOR THE MOST PART AND A CHANGEOVER TO
SNOW AS THE PRECIPITATION ENDS SUNDAY NIGHT. MODEL SOLUTIONS ARE
CLOSER TO EACH OTHER ON THE NEXT WAVE WHICH CROSSES MIDWEEK...WITH
THE NEXT SHOT OF PRECIPITATION.
ASIDE FROM THE COLD START TO THE WEEKEND...TEMPERATURES MUCH OF
THIS PERIOD WILL BE SEVERAL DEGREES ABOVE NORMAL.
GEELHART
&&
.AVIATION...
ISSUED 543 AM CST THU JAN 19 2012
CONDITIONS WILL BE PRIMARILY VFR AT ALL TAF SITES THROUGH THE
PERIOD. A QUICK MOVING WINTER SYSTEM WILL BRING TEMPO SNOW/MVFR
CIGS/VIS TO PIA/BMI/CMI THIS MORNING THROUGH ABOUT NOON...WHILE
SPI/DEC JUST WILL HAVE VCSH AND SCATTERED AT 2.5KFT. ONCE SYSTEM
PASSES CLOUDS HEIGHTS WILL RISE AGAIN AND WILL BE LEFT WITH JUST
CIRRUS CLOUDS FROM THIS AFTERNOON THROUGH TONIGHT. WINDS WILL BE
SOUTHWEST AHEAD OF THE FRONT BUT QUICKLY SWITCH TO NORTHWEST
BEHIND THE FRONT. EXPECT NORTHERLY WINDS THIS AFTERNOON THROUGH
THIS EVENING...BECOMING NORTHEAST OVERNIGHT. TIGHT TEMP GRADIENT
BEHIND FRONT WILL BRING SOME STRONGER WINDS...BUT GRADIENT WEAKENS
A FEW HOURS BEHIND THE FRONT SO WINDS WILL DECREASE REST OF THE
PERIOD.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
248 AM CST THU JAN 19 2012
.DISCUSSION...
ISSUED 245 AM CST THU JAN 19 2012
SHARP ARCTIC COLD FRONT IS ABOUT TO MOVE INTO THE NORTHWEST TIP OF
THE CWA AT 08Z...OVERALL EXTENDING FROM EAST CENTRAL WISCONSIN TO
AROUND KANSAS CITY. TEMPERATURES QUICKLY DROP OFF INTO THE SINGLE
DIGITS AS CLOSE AS CENTRAL IOWA. AREA OF LIGHT SNOW SO FAR HAS
MAINLY BEEN BEHIND THE FRONT. UPSTAIRS...VERY TIGHT UPPER FLOW
CONTINUES...WITH EVENING UPPER AIR ANALYSIS SHOWING A SCREAMING
150+ KNOT JET AT 300 MB FROM AROUND SEATTLE SOUTHEAST INTO
MISSOURI.
MAIN FORECAST CHALLENGE WITH THIS PACKAGE IS WITH PRECIPITATION
TYPES FRIDAY AND FRIDAY NIGHT. THE EFFECTS OF THE CURRENT SYSTEM
ARE A SECONDARY CONCERN.
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
LATEST HRRR MODEL SWEEPS THE FRONT ACROSS THE CWA THIS MORNING...
LINGERING THROUGH MIDDAY ACROSS THE FAR SOUTHEAST. BEST LIFT WITH
THIS FRONT IS STILL EXPECTED OVER THE NORTHEAST THIRD OF THE
CWA...WITH 1-2 INCHES OF SNOW EXPECTED NORTH OF A BLOOMINGTON TO
DANVILLE LINE THROUGH EARLY AFTERNOON. SHARP SOUTHERN CUTOFF TO
THE SNOW IS EXPECTED...AND WENT WITH ONLY SLIGHT CHANCES SOUTH OF
A JACKSONVILLE TO TERRE HAUTE LINE. ONLY THE SOUTHEAST CWA IS
EXPECTED TO SEE TEMPERATURES RISE ABOVE FREEZING...WITH MOST OF
THE FORECAST AREA SEEING FALLING DAYTIME TEMPERATURES.
THE FRIDAY STORM SYSTEM CONTINUES TO HAVE SEPARATE CONCERNS...ONE
WITH THE SNOW ACROSS THE NORTH IN THE STRONGER LIFT AND BAROCLINIC
ZONE...AND THE POTENTIAL FOR MIXED PRECIPITATION FURTHER SOUTH
CLOSER TO THE SURFACE FEATURES. SNOW-WISE...BEST LIFT STILL
EXPECTED JUST TO OUR NORTH ACROSS NORTHERN ILLINOIS...BUT 2-3
INCHES IS LIKELY AS FAR SOUTH AS GALESBURG AND PEORIA FRIDAY INTO
FRIDAY EVENING. FURTHER SOUTH...FORECAST SOUNDINGS SHOWING A
WEDGE OF WARM AIR AROUND 900 MB MOVING IN LATER FRIDAY AFTERNOON
AND ESPECIALLY DURING THE EVENING. THE NAM IS MOST PRONOUNCED WITH
THIS AROUND CHAMPAIGN AND MATTOON...WHILE THE GFS IS FURTHER SOUTH
TOWARD LAWRENCEVILLE AND THE LOCAL WRF IN BETWEEN. EVAPORATIVE
COOLING WOULD FAVOR MORE OF A SLEET/SNOW MIXTURE INITIALLY...THEN
SOME FREEZING RAIN AND SLEET IN THE EVENING BEFORE SWITCHING OVER
TO SNOW LATE TONIGHT. WILL INCLUDE SOME LOW ICE ACCUMULATIONS IN
AREAS MAINLY BETWEEN I-72 AND I-70...WITH LOCATIONS FROM MATTOON
TO PARIS WITH THE HIGHEST AMOUNTS OF AROUND 0.05 INCH OR SO. MAY
NEED TO CONSIDER WINTER WEATHER ADVISORIES IN SOME PARTS OF THE
CWA...BUT ENOUGH MODEL VARIABILITY EXISTS TO PRECLUDE ISSUING ONE
AT THIS TIME.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
PRECIPITATION TO BE OUT OF THE AREA BEFORE SUNRISE SATURDAY...WITH
HIGH PRESSURE RESULTING IN DRY WEATHER. FOCUS IN THE LONGER TERM
SHIFTS TO A DIGGING SHORTWAVE WHICH WILL CROSS THE MIDDLE OF THE
NATION SUNDAY NIGHT AND MONDAY. FOLLOWED THE SLOWER ECMWF/CANADIAN
SOLUTIONS...WHICH FAVOR RAIN FOR THE MOST PART AND A CHANGEOVER TO
SNOW AS THE PRECIPITATION ENDS SUNDAY NIGHT. MODEL SOLUTIONS ARE
CLOSER TO EACH OTHER ON THE NEXT WAVE WHICH CROSSES MIDWEEK...WITH
THE NEXT SHOT OF PRECIPITATION.
ASIDE FROM THE COLD START TO THE WEEKEND...TEMPERATURES MUCH OF
THIS PERIOD WILL BE SEVERAL DEGREES ABOVE NORMAL.
GEELHART
&&
.AVIATION...
ISSUED 1115 PM CST WED JAN 18 2012
TIMING OF COLD FRONT...LIGHT SNOW AND POSSIBLY MVFR CIGS ACROSS
THE TAF SITES THE MAIN FORECAST CONCERN THIS PERIOD. COLD FRONT
HAS PUSHED INTO EAST CENTRAL IOWA...A BIT QUICKER THAN EARLIER
THOUGHT...AND SHOULD NOW APPROACH THE ILLINOIS RIVER VALLEY
BETWEEN 09Z AND 11Z. HAVE SEEN AN INCREASE IN LIGHT SNOW OVER
THE PAST SEVERAL HOURS OVER PARTS OF NORTHEAST IOWA WITH THE IR
SATELLITE LOOP SHOWING AN INCREASE IN COVERAGE OF COLDER CLOUD
TOPS ASSOCIATED WITH THE NEXT UPPER LEVEL WAVE AND STRONG JET
MAX TO OUR WEST.
IT STILL APPEARS MOST OF THE LOWER CIGS AND ANY SNOW WILL BE
BEHIND THE COLD FRONT FOR ABOUT A 4-6 HOUR PERIOD STARTING THURS
MORNING WITH MOST OF THE LOWER CIGS AND SNOW TO OUR EAST BY
20Z...WITH VFR CONDITIONS PREVAILING INTO THURSDAY NIGHT.
ACCUMULATIONS STILL LOOK TO BE AROUND AN INCH NORTH OF A SPI TO
CMI LINE TOMORROW MORNING. SFC WINDS WILL CONTINUE FROM THE SOUTH
AND SOUTHWEST OVERNIGHT AND SWITCH INTO THE NORTHWEST AFTER FROPA
AROUND 10Z AT PIA...BTWN 11Z AND 12Z AT BMI AND SPI...WITH THE
FRONT TO THE EAST OF CMI BY 15Z.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
646 PM EST FRI JAN 20 2012
.AVIATION...
RADAR TRENDS...OBSERVATIONS AND HIRES MODEL GUIDANCE USED FOR
AVIATION FORECASTS WITH FOCUS ON NEXT SIX HOURS. KSBN WILL REMAIN IN
AREA OF MODERATE TO HEAVY SNOW WITH VIS EXPECTED TO REMAIN AT ONE
HALF MILE WITH DROPS TO ONE QUARTER MILE FOR NEXT TWO TO FOUR HOURS.
HEAVIER SNOW BEGINNING TO DIMINISH NEAR AND JUST WEST OF CHICAGO
AREA SO SHOULD SEE SLOW IMPROVEMENT AFTER 03Z THEN RAPID IMPROVEMENT
AFTER 06Z WITH DRIER AIR MOVING IN. RADAR SHOWING DRY SLOT PUSHING
NORTH TOWARD KFWA AND IT MAY JUST REACH AIRPORT BRIEFLY BEFORE
HIGHER RETURNS TO WEST ROTATE BACK IN. FOR NOW HAVE KEPT THE AIRPORT
SOCKED IN GIVEN SHORT DURATION OF ANY POSSIBLE BREAK THERE. VIS MAY
BRIEFLY DROP BELOW ONE QUARTER MILE BUT FOR NOW HAVE STAYED WITH
RESTRICTIONS AROUND ONE HALF AS THAT LOOKS MOSTLY LIKELY WITH LOWER
VIS TO THE NORTH OF AIRPORT. WILL MONITOR THOUGH AS SOME HIGHER
RETURNS DEVELOPING WEST OF AIRPORT.
&&
.UPDATE...
SNOW EVENT EVOLVING AS EXPECTED SO FAR. UPSTREAM REPORTS IN NORTHERN
IL INDICATE EXPECTED POTENTIAL FOR SOME AMOUNTS NEAR OR JUST ABOVE 6
INCHES. CURRENT ADVISORY HAS THIS WELL IN HAND WITH WORDING SO
CURRENTLY NO PLANS TO UPGRADE HEADLINES UNLESS WE START GETTING
WIDESPREAD REPORTS IN EXCESS OF 6 TO 7 INCHES LATER THIS EVENING
WITH ADDITIONAL SNOWFALL EXPECTED. MOST REPORTS SO FAR IN THE 1 TO 3
INCH RANGE WITH A FEW EXCEPTIONS. VISIBILITIES BEGINNING TO RISE
SLOWLY NEAR AND WEST OF CHICAGO SO EXPECT OUR WESTERN AREAS TO SEE
THIS MODERATE TO BRIEFLY HEAVY SNOW FOR A FEW MORE HOURS BEFORE
SNOWFALL RATES GRADUALLY DECREASE THERE WITH PROGRESSION EAST
THROUGH THE LATE EVENING AND OVERNIGHT HOURS. HIGH RES GUIDANCE ALSO
SHOWING THIS WITH HRRR LOOKING VERY GOOD SO FAR.
&&
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
MAIN FORECAST FOCUS WILL CONTINUE TO CENTER ON SIGNIFICANT SNOW
ACCUMULATIONS TONIGHT. A WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT FOR THE ENTIRE FORECAST AREA THROUGH 12Z SATURDAY.
A ZONE OF STRONG ISENTROPIC UPGLIDE PER RUC/GFS 290K SFC WILL
CONTINUE TO LIFT NORTHEAST ACROSS NORTHERN PORTIONS OF THE FORECAST
AREA. SEVERAL REPORTS NOW OF 1/2 TO 1/4 MILE VSBYS ACROSS NORTHERN
ILLINOIS AND STRONGEST ISENTROPIC ASCENT SHOULD SHIFT EASTWARD
ACROSS NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN IN THE 22Z-03Z
TIMEFRAME. DURING THIS PERIOD OF STRONGER FORCING...STRONGEST UPWARD
VERTICAL MOTION SHOULD BE SOLIDLY ENCOMPASSED IN FAVORABLE DENDRITIC
GROWTH ZONE. THUS...SHOULD SEE A PERIOD EARLY THIS EVENING WHERE
SNOW TO LIQUID RATIOS INCREASE SHARPLY FOR A TIME. ISENTROPIC PROGS
HAVE ALSO SUGGESTED PERHAPS A SLIGHT WEAKENING OF THE ISENTROPIC
LIFT THIS EVENING AS VORT MAX SKIRTING ACROSS SOUTHERN WISCONSIN
THIS AFTERNOON BECOMES MORE SHEARED ACROSS THE SOUTHERN LAKES.
NONETHELESS...A 2 TO 4 PERIOD OF SNOWFALL RATES AROUND AN INCH PER
HOUR APPEARS TO BE POSSIBLE LATE THIS AFTERNOON/EARLY THIS EVENING
FOR AREAS ESPECIALLY ALONG AND NORTH OF THE ROUTE 30 CORRIDOR.
ACCUMULATIONS WILL BE IN SOMEWHAT MORE QUESTION ACROSS THE SOUTH AS
THIS BAND SHOULD PROVIDE GREAT IMPACTS ACROSS THE NORTHERN HALF.
WATER VAPOR IMAGERY CONTINUES TO INDICATE A STRONGER VORT MAX
DROPPING INTO THE CENTRAL PLAINS THAT WILL BEGIN TO SHIFT EASTWARD
INTO THE MID MS RVR VALLEY LATER THIS EVENING. SHOULD START TO SEE A
MORE FRONTALLY FORCED AREA OF SNOW DEVELOP EXTENDING SOUTHWEST FROM
THIS INITIALLY WEST TO EAST ORIENTED BAND THAT WILL AFFECT
CENTRAL/SOUTHERN AREAS LATE THIS EVENING. STILL EXPECTING STORM
TOTAL SNOWFALL AMOUNTS IN THE 4 TO 7 RANGE CENTRAL AND NORTH...WITH
AMOUNTS IN THE 2 TO 4 RANGE FAR SOUTH. GFS/RUC VERTICAL CROSS
SECTIONS ALSO INDICATE INCREASING INSTABILITY ALOFT (NEGATIVE EPV)
LIFTING ACROSS EASTERN SECTIONS OF THE AREA LATE THIS EVENING AS
SOUTHWESTERLY FLOW STRENGTHENS IN ADVANCE OF THIS SECONDARY SHORT
WAVE. THIS INCREASE IN INSTABILITY ALOFT SHOULD CORRESPOND TO THIS
SECONDARY MID LEVEL FORCING MAX WITH THIS SHORT WAVE...SO HAVE
KEPT AMOUNTS MORE SOLIDLY IN THE ADVISORY RANGE IN THE FAR
SOUTHEAST...WITH SLIGHTLY LESSER TOTALS IN THE SOUTHWEST.
CURRENTLY HAVE DRAWN UP TOTAL ACCUMULATIONS JUST BELOW ADVISORY
CRITERIA ACROSS THE SOUTHWEST BUT DUE TO COMPLICATING MESOSCALE
FORCING MECHANISMS MENTIONED...WILL MAINTAIN ALL HEADLINES AT THIS
TIME.
CONDITIONS TO IMPROVE FROM WEST TO EAST OVERNIGHT WITH THE PASSAGE
OF THIS SECONDARY VORT MAX. ORIENTATION OF RIDGE AXIS TO THE WEST
SHOULD SUPPORT ANY LAKE EFFECT SNOW SHOWERS WEST OF THE LOCAL
FORECAST AREA INTO NORTHWEST INDIANA/NORTHEAST ILLINOIS. SATURDAY
SHOULD FEATURE QUIET WEATHER WITH SFC HIGH BEGINNING TO BUILD IN.
WEAK LOW LEVEL EASTERLIES AND NEW SNOW COVER SHOULD PROMOTE WEAK
MIXING AND HAVE UNDERCUT MOST AVAILABLE GUIDANCE FOR HIGH TEMPS.
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY
MID LEVEL FLOW TRANSITION STILL ON TRACK IN THE PERIOD GIVEN THE
RETURN OF ALASKA TROUGHING...WITH MUCH MILDER PAC ORIGIN DOWNSLOPE
FLOW EXPECTED INTO THE REGION BY EARLY NEXT WEEK. A DEEP LONGWAVE
TROUGH IS STILL EXPECTED IN THE SUN NIGHT-MON PERIOD...SUPPORTING
ROBUST LL FLOW FIELDS WITH SIG THETA-E ADVECTION INTO THE AREA.
SPLIT FLOW REGIME WILL FOLLOW WITH STRONG MODEL/ENSEMBLE SUPPORT
CONTINUING. FAST PERTURBED WNW FLOW WILL OFFER LOW CONFIDENCE PER
DISTURBANCE TIMING IN THE LATE PERIODS GIVEN TYPICAL POOR MODEL
PERFORMANCE PER THESE FEATURES. HENCE...NO SIG CHANGE PER PRECIP
CHANCE WED-FRI...WITH PREFERENCE TOWARD 24-36 HOUR FORECAST WINDOWS
PER PRECIP CHANCES GIVEN INHERENT VARIABILITY PER IMPULSE TIMING.
SUN-MON...SIG MID LEVEL TROUGH IS STILL ON TRACK TO DIG INTO THE SW
CONUS AND BEGIN TO EJECT TOWARD THE REGION. ECMWF/GEM/UKMET ARE
PREFERRED GIVEN THEIR HANDLING OF THE DIGGING MID LEVEL TROUGH WITH
NEGATIVE TILT CHARACTERISTICS. CERTAINLY DONT BUY THE NAM/S OUTLIER
NORTH BIAS PER THE SFC CYCLONE AND THE GFS/S WILD VARIABILITY PER
TROUGH DEPTH/TIMING/AND TRACK. CONTINUED MODEL SUPPORT FOR A STRONG
SOUTHERN PERIPHERY UPPER JET STREAK AND NEGATIVE UPPER TROUGH TILT
SUGGESTS A WEST BIAS TO THE SFC LOW TRACK WITH SLOWER SYSTEM ARRIVAL
AND HAVE CONTINUED THIS IN THE GRIDS. SYSTEM INFLUENCE TO THE LOCAL
AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY FLOW
INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC ZONE
IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE EJECTING MID
LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE FALLS...SUPPORTING
RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL THETA-E ADV TO ENSUE
LATE SUNDAY IN THE REGION WITH SIG SFC LAYER DEWPOINT RISES BY
SUNDAY NIGHT. STAUNCH LL FLOW WITH A 60 TO 70 KNOT LLJ PROGGED IN
THE ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT DEEP LAYER THETA-E
RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A SATURATED BL WITH
DRIZZLE AND FOG EXPECTED TO DEVELOP LATE SUNDAY AFTERNOON /AT THE
EARLIEST/ INTO THE EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT.
ECMWF H7-H3 LAYER ANALYSIS CONTINUES TO INDICATE AN INTACT EML WITH
STEEP MID LEVEL LAPSE RATES GIVEN STRONG LOW CENTERED WAA. H85
THETA-E APPROACHES 325K BY LATE SUNDAY NIGHT...WITH SW INDICES
NEGATIVE...INDICATING A GOOD ENVIRONMENT FOR ELEVATED THUNDERSTORMS.
HAVE MAINTAINED A LOW CHANCE THUNDER AT THIS POINT. ALBEIT
SMALL...THERE REMAINS A SMALL CONCERN FOR SEVERE WEATHER GIVEN
INDICATED H5 JETLET IN EXCESS OF 85 KNOTS...WHICH WOULD BE CAPABLE
OF SUPPORTING A QLCS JET DRIVEN THIN LINE. CONCERNS FOR INCREASED
FLOODING CONTINUE GIVEN FULL SNOWPACK MELT WITH THE POTENTIAL FOR
HEAVY RAIN. IN ADDITION...A SLOWER TROUGH ARRIVAL PER NEGATIVE
TROUGH TENDENCIES WOULD SUPPORT HIGHS INTO THE 50S AKIN TO ECMWF
PROGS. CAA WILL DOMINATE MONDAY WITH FALLING TEMPS IN THE DAYTIME
PERIOD LIKELY. LINGERING LIGHT SNOW SHOWERS WILL BE POSSIBLE.
TUE-FRI...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED-THUR PERIOD AND HAVE RETAINED POPS THEN...OPTING
TO KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS. HAVE ALSO
EXTENDED THIS MENTION INTO FRIDAY MAINLY PER COLLAB WITH SURROUNDING
OFFICES...WHICH ALSO FITS THE ACTIVE PATTERN. OTHERWISE...ADJUSTED
TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY ONCE AGAIN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ SATURDAY FOR
INZ003>009-012>018-020-022>027-032>034.
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ077>081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR OHZ001-002-
004-005-015-016-024-025.
LM...NONE.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...LASHLEY
UPDATE...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
410 PM EST THU JAN 19 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
SIGNIFICANT SNOW ACCUMULATIONS FRIDAY/FRIDAY NIGHT WILL BE THE MAIN
CONCERN FOR THE SHORT TERM. A WINTER WEATHER ADVISORY WILL BE ISSUED
FOR LATE MORNING FRIDAY THROUGH FRIDAY NIGHT FOR APPROXIMATELY
NORTHERN TWO THIRDS OF THE FORECAST AREA.
ACCUMULATING LIGHT SNOW THIS AFTERNOON HAS SHIFTED WELL SOUTH OF
ROUTE 30 LATE THIS AFTERNOON...AND WILL CONTINUE TO SAG SOUTHWARD
THROUGH THE REMAINDER OF THE LATE AFTERNOON HOURS AS AXIS OF LOW
LEVEL FRONTOGENESIS PUSHES SOUTH OF THE FORECAST AREA. FURTHER TO
THE NORTH...LAKE EFFECT SNOW SHOWERS HAVE BEEN INCREASING IN
INTENSITY WITH FAIRLY STRONG 850 HPA/LAKE DELTA TEMPS ON THE ORDER
OF 20 TO 23 DEGREES. RUC SOUNDINGS SUGGEST A NEARLY ISOTHERMAL LAYER
FROM 850 TO 700 HPA WHICH IS LIMITING DEPTH OF THIS LAKE GENERATED
INSTABILITY WITH LAKE INDUCED EQUILIBRIUM HEIGHTS ON THE ORDER OF
ABOUT 5K FT. ANOTHER NEGATIVE FACTOR POINTING AGAINST SIGNIFICANT
LAKE EFFECT SNOW ACCUMULATIONS IS MUCH DRIER MID LEVEL AIR THAT WAS
WORKED INTO THE SOUTHERN GREAT LAKES REGION BEHIND THE SYSTEM WHICH
BROUGHT THE ACCUMULATING SNOW TODAY. THIS MARGINAL LAKE EFFECT SETUP
WILL CONTINUE FOR MUCH OF THE EVENING AND INTO THE OVERNIGHT...AND A
FEW LOCATIONS MAY PICK UP A HALF INCH TO AN INCH OF ADDITIONAL
ACCUMULATION BEFORE INVERSION HEIGHTS CRASH MORE SUBSTANTIALLY
DURING THE OVERNIGHT HOURS. AREAS AWAY FROM LAKE EFFECT
CLOUDS/PRECIP SHOULD CLEAR THIS EVENING. A WEAKENING GRADIENT WITH
SFC RIDGE AXIS BUILDING IN COMBINED WITH THIS CLEARING SHOULD
ALLOW FOR VERY COLD TEMPS TONIGHT INTO THE SINGLE DIGITS ABOVE
ZERO. SOME INCREASE IN HIGH CLOUDS IS EXPECTED LATE TONIGHT THAT
MAY LEVEL OUT TEMPERATURES AFTER 09Z.
ATTENTION WILL THEN TURN TO WHAT WILL BE A VERY FAST MOVING UPPER
LEVEL SYSTEM THAT IS APPROACHING THE PACIFIC NORTHWEST COAST AT THIS
TIME. LOW LEVEL WINDS WILL BACK SOUTHWESTERLY ON FRIDAY AHEAD OF
THIS TROUGH WHICH WILL SET UP A PERIOD OF INTENSE ISENTROPIC UPGLIDE
FRIDAY AFTERNOON/EARLY EVENING OVER THE SHALLOW RETREATING ARCTIC
AIR MASS. STRONG FRONTOGENETIC FORCING ALSO TO DEVELOP IN THE
850/700 LAYER AS THIS LOW LEVEL FLOW RAMPS UP. 12Z NAM REMAINS A
SLIGHTLY SLOWER AND FURTHER NORTH OUTLIER IN REGARDS TO THIS
SYSTEM...WITH 09Z SREF GENERALLY LENDING SUPPORT TO THE MORE RUN TO
RUN CONSISTENT GFS/ECMWF. GENERALLY UTILIZED A PREDOMINATELY
SREF/GFS/ECMWF BLEND FOR THIS FORECAST WITH A MUCH SMALLER
WEIGHTING TOWARD NAM. PERIOD OF MOST INTENSE SNOWFALL APPEARS TO
BE SHAPING UP IN THE 21Z-03Z TIMEFRAME WITH BEST COLOCATION OF
STRONGER SYNOPTIC LIFT WITH FAVORABLE DENDRITIC GROWTH ZONE.
MODEL QPF FROM 12Z SUITE OF MODELS STILL TEND TO SUPPORT MAINLY
HIGH END ADVISORY LEVEL SNOW ACCUMULATIONS WHEN CONSIDERING
EXPECTED SNOW TO LIQUID RATIOS ON THE ORDER OF 15:1 ACROSS THE
NORTH.
CONCERN WITH THESE TYPE OF INTENSE LOW/MID LEVEL BAROCLINIC ZONES IS
FOR AREAS OF ENHANCED BANDING WHICH COULD PUSH SOME AREAS INTO LOW
END WARNING ACCUMULATIONS. 12Z GFS MODEL CROSS SECTIONS STILL
INDICATE RELATIVELY HIGH STATIC STABILITY ATOP THIS LOW LEVEL
FRONTOGENESIS FORCING WHICH MAY TEND TO DISCOURAGE SMALLER SCALE
INTENSE BANDING...AND A BROADER RESPONSE IN UPWARD VERTICAL MOTION
FIELDS. SYSTEM ALSO WILL BE VERY PROGRESSIVE WITH SOME INDICATIONS
OF ISENTROPIC UPGLIDE WEAKENING SLIGHTLY FROM WEST TO EAST INTO
NORTHEAST INDIANA BY EVENING. TAKING THE ABOVE FACTORS INTO
CONSIDERATION HAVE OPTED TO GO WITH A HIGH END WINTER WEATHER
ADVISORY FOR SNOW ACCUMULATIONS OF 3 TO 7 INCHES NORTHERN TWO
THIRDS...WITH THE HIGHER ACCUMULATIONS EXPECTED FAR NORTHERN
INDIANA/SOUTHERN LOWER MICHIGAN. WINDS NOT EXPECTED TO BE AN OVERLY
HUGE CONCERN WITH THIS SYSTEM...BUT A BRIEF PERIOD IN THE 21Z-03Z
TIMEFRAME OF 1 TO 2 INCH PER HOUR SNOWFALL RATES APPEARS TO BE A
GOOD POSSIBILITY. IN TRENDING MORE TOWARD GFS...HAVE CONFINED MIXED
PRECIP MENTION TO A CHANCE OF SLEET ACROSS THE SOUTH BUT THIS WILL
NEED TO BE WATCHED IN FUTURE FORECASTS ONCE CONFIDENCE IN LOW LEVEL
THERMAL FIELDS INCREASES. SNOW WILL BEGIN TO WANE LATE FRIDAY NIGHT
WITH INDICATIONS OF FAR SOUTHEAST GETTING INTO SOME ENHANCED
SNOWFALL AS A PIECE OF EASTERN PACIFIC SHORT WAVE DIGS MORE
AGGRESSIVELY INTO THE OHIO RIVER VALLEY.
&&
.LONG TERM...
SUNDAY THROUGH THURSDAY
SIG PATTERN ADJUSTMENT TO OCCUR IN THE LONG TERM PERIOD AS REX BLOCK
RIDGING SHIFTS WEST OVER ALASKA...WITH SUBSTANTIAL UPPER LEVEL
TROUGHING EXPECTED THERE BY THIS WEEKEND. THIS WILL RESULT IN A
SWITCH BACK TO FAST WESTERLY GENERALLY MILD FLOW...WITH EMBEDDED FAST
MOVING IMPULSES PROVIDING PERIODIC CHANCES FOR RAIN/SNOW. THIS WILL
OCCUR AFTER THE ADVECTION OF A POTENT MID LATITUDE CYCLONE EARLY
NEXT WEEK...A SYSTEM WHICH COULD BRING A SUBSTANTIAL AMOUNT OF
RAIN/WIND/AND EVEN THUNDERSTORMS TO THE AREA SUNDAY NIGHT INTO
MONDAY MORNING. ECMWF/GFS/AND GEFS SOLUTIONS CONTINUE TO REMAIN
NEARLY PHASED PER HEIGHT SOLUTIONS IN THE PERIOD...WITH INCREASED
FORECAST CONFIDENCE IN THE PERIOD.
SAT-MON...FRIDAY SYSTEM WILL BE IN THE PROCESSES OF EXITING THE REGION
WITH A LOW CHANCE FOR LINGERING LIGHT SNOW FAR SE SAT AM. WEAK
SUBSIDENT REGIME WITH SFC RIDGING WILL SUPPORT GRADUAL EROSION OF
LINGERING LOW CLOUDS...WITH WINDS VEERING SE THROUGH THE SAT PERIOD.
MEANWHILE...A SIG MID LEVEL TROUGH IS EXPECTED TO DIG INTO THE SW
CONUS AND BEGIN TO EJECT TOWARD THE REGION. SYSTEM INFLUENCE TO THE
LOCAL AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY FLOW
INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC ZONE
IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE EJECTING MID
LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE FALLS...SUPPORTING
RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL THETA-E ADV TO ENSUE
SUNDAY IN THE REGION WITH SIG SFC LAYER DEWPOINT RISES INTO SUNDAY
NIGHT. STAUNCH LL FLOW WITH A 60 TO 70 KNOT LLJ PROGGED IN THE
ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT DEEP LAYER THETA-E
RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A SATURATED BL WITH
DRIZZLE AND FOG EXPECTED TO DEVELOP SUNDAY AFTERNOON INTO THE
EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT. ECMWF H7-H3 LAYER
ANALYSIS REVEALS A RATHER IMPRESSIVE EML WITH STEEP MID LEVEL LAPSE
RATES GIVEN STRONG LOW CENTERED WAA. H85 THETA-E APPROACHES 325K BY
LATE SUNDAY NIGHT...WITH SW INDICES NEGATIVE...INDICATING A GOOD
ENVIRONMENT FOR ELEVATED THUNDERSTORMS. HAVE INTRODUCED A LOW CHANCE
THUNDER AT THIS POINT. ALBEIT SMALL...THERE IS A CONCERN FOR SEVERE
WEATHER GIVEN INDICATED H5 JETLET IN EXCESS OF 90 KNOTS...WHICH
WOULD BE CAPABLE QLCS JET DRIVEN CELLS. PERHAPS THE BIGGEST CONCERN
ATTM IS FOR INCREASED FLOODING CONCERNS GIVEN FULL SNOWPACK MELT
WITH THE POTENTIAL FOR HEAVY RAIN. WILL HIGHLIGHT IN AN ESF.
NEGATIVE TROUGH TILT INDICATED IN FORECAST MODELS SUGGEST A NW TRACK
ADJUSTMENT PER THE SFC LOW...WITH A SLOWER SYSTEM ARRIVAL
POSSIBLE...IN ADDITION TO WARMER THERMAL FIELDS. HENCE DROPPED THE
SNOW MENTION SUN NIGHT/TRIMMED MONDAY SNOW MENTION/AND ADJUSTED
TEMPS UP. CAA WILL DOMINATE MONDAY WITH FALLING TEMPS IN THE DAYTIME
PERIOD LIKELY. LINGERING LIGHT SNOW SHOWERS WILL BE POSSIBLE MAINLY
NW.
TUE-THUR...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED PERIOD AND HAVE RETAINED POPS THEN...OPTING TO
KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS.
OTHERWISE...ADJUSTED TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY
ONCE AGAIN.
&&
.AVIATION...
18Z TAFS...MODERATE SNOW WILL CONTINUE TO AFFECT KFWA THROUGH 20Z
BEFORE DIMINISHING AS AN UPPER LEVEL DISTURBANCE AND ASSOCIATED
LOW LEVEL FRONTAL BOUNDARY SAG SOUTHEAST. PERIODS OF LAKE EFFECT
SNOW SHOWERS WILL ALSO AFFECT KSBN THROUGH AT LEAST EARLY EVENING.
HAVE CARRIED MVFR CONDITIONS TO COVER THIS LAKE EFFECT POTENTIAL
ALTHOUGH SOME SHORT LIVED IFR VSBYS MAY BE ASSOCIATED WITH THE
STRONGER BANDS. NORTHWEST WINDS TO CONTINUE TO DROP OFF IN SPEED
THROUGH THE REMAINDER OF THE NIGHT...EVENTUALLY BECOMING SOUTHEAST
BY FRIDAY MORNING. DID MAINTAIN MVFR CIGS AT TERMINALS THIS
EVENING DUE TO TRAJECTORIES UPWIND OF LAKE MICHIGAN AND WEAKENING
LOW LEVEL FLOW...ALTHOUGH CONFIDENCE IS LOW IN DURATION OF THESE
MVFR CIGS WITH A POSSIBILITY OF VFR CIGS AT KFWA EVEN BY LATER
THIS AFTERNOON. CONDITIONS TO DETERIORATE AGAIN ON
FRIDAY...ESPECIALLY TOWARD THE END OF THIS FORECAST PERIOD AS NEXT
SYSTEM BRINGS A MORE SIGNIFICANT ROUND OF SNOW TO NORTHERN INDIANA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ FRIDAY TO 7 AM
EST /6 AM CST/ SATURDAY FOR INZ003>009-012-014-016>018.
MI...WINTER WEATHER ADVISORY FROM 10 AM FRIDAY TO 7 AM EST SATURDAY
FOR MIZ077>081.
OH...WINTER WEATHER ADVISORY FROM 10 AM FRIDAY TO 7 AM EST SATURDAY
FOR OHZ001-002-004-005-015-016.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1158 AM MST THU JAN 19 2012
.UPDATE...
1158 AM MST THU JAN 19 2012
LATEST SATELLITE IMAGERY SHOWS THAT THE COLD FRONT IS MOVING
EASTWARD AWAY FROM ITS EARLIER POSITION NEAR THE KS/CO BORDER.
TEMPERATURES IN EASTERN CO HAVE WARMED INTO THE 50S...WHILE
TEMPERATURES IN SOUTHWESTERN NE ARE STRUGGLING TO LEAVE THE MID
TEENS. HAVE ADJUSTED HIGH TEMPERATURES TO BE WARMER IN CO AND
COOLER WELL BEHIND THE FRONT.
CJS
&&
.DISCUSSION...
220 AM MST THU JAN 19 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE EASTERN US...WITH W/NW FLOW
EXTENDING ACROSS THE CENTRAL PART OF THE COUNTRY. AT THE SURFACE A
STRONG COLD FRONT HAS SETTLED OVER THE CWA...WITH A 20F SPREAD IN
TEMPS BETWEEN THE SW PART OF THE CWA AND THE NE.
TODAY-SATURDAY...WITH DRY CONDITIONS EXPECTED THE MAIN FORECAST
CONCERN WILL CONTINUE TO BE TEMPERATURES AS THE PREVIOUSLY MENTIONED
FRONT AND ASSOCIATED BAROCLINIC ZONE LINGERS ACROSS PORTIONS OF
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. 30F SPREAD IN HIGH TEMPS
CURRENTLY FORECAST FROM THE EAST TO THE WEST TODAY...WITH AREAS WEST
OF THE FRONT APPROACHING THE MID 50S...AND EAST OF THE FRONT IN THE
MID/UPPER 20S. BETWEEN THESE EXTREMES IT IS DIFFICULT TO PIN DOWN
HIGH TEMPS CONSIDERING THE EXTREME TEMPERATURE GRADIENT THAT
WILL BE IN PLACE...SO HAVE USED A GENERAL BLEND OF PREVIOUS FORECAST
AND LATEST SHORT-RANGE GUIDANCE. TEMPS WILL BEGIN TO MODERATE SOME
ACROSS EASTERN PARTS OF THE AREA FRIDAY...BEFORE A BACKDOOR COLD
FRONT REINFORCES SHALLOW COLD AIR MASS FRIDAY AFTERNOON/EVENING.
SHALLOW COLD AIR MASS BEGINS TO SCOUR OUT WITH TEMPS MODERATING
AHEAD OF SHORTWAVE TROUGH MOVING TOWARDS THE GREAT BASIN...THOUGH
THERE WILL STILL BE A 15-20F GRADIENT FROM EAST TO WEST.
SATURDAY NIGHT...SHORTWAVE TROUGH MOVES TOWARDS THE CENTRAL ROCKIES
SATURDAY NIGHT...WITH INCREASING LARGE SCALE ASCENT OVER THE CWA
AFTER 06Z. NAM/GFS BOTH ARE WEAKER/QUICKER WITH THIS SYSTEM...AND
KEEP CONDITIONS DRY OVER CWA. ECMWF CONTINUES TO SHOW
STRONGER/WETTER SOLUTION. I WAS HESITANT TO JUMP ON THE WET ECMWF
SOLUTION YET...WITH TIMING/STRENGTH STILL IN QUESTION. WITH THE
AMOUNT OF LIFT PRESENT AND LIMITED MOISTURE ADVECTION I COULDNT RULE
OUT SOME FLURRIES IN THE NORTH...BUT WASNT CONFIDENT ENOUGH TO ADD
DURING THIS CYCLE.
DR
FOR THE PERIOD SUNDAY THROUGH WEDNESDAY...RELATIVELY QUIET WEATHER
EXPECTED THROUGH THE ENTIRE PERIOD. A COLD FRONT WILL MOVE THROUGH
THE REGION MONDAY NIGHT AND TUESDAY...HOWEVER PRECIPITATION CHANCES
APPEAR THEY WILL STAY SOUTH AND EAST OF THE LOCAL FORECAST AREA. IT
WILL BRING A PERIOD OF GUSTY NORTH WINDS...PROBABLY TUESDAY
MORNING....AND COOLER TEMPERATURES TUESDAY AND WEDNESDAY...ALBEIT
STILL ABOVE NORMAL.
024
&&
.AVIATION...
1050 AM MST THU JAN 19 2012
FOR THE 18Z TAFS...ARCTIC COLD CURRENTLY LOCATED NEAR THE KS/CO STATE
LINE. THIS FEATURE WILL CREATE SOME UNCERTAINTY AT KGLD WITH RESPECT
TO TIMING OF WIND SHIFTS...BUT A GENERAL VEER FROM EAST/SOUTHEAST TO
THE SOUTH IS EXPECTED DURING THE AFTERNOON HOURS. ALSO OF NOTE ARE LOW
IFR CIGS CURRENTLY LOCATED JUST TO THE NORTH OF KGLD...BUT THESE LOW
CIGS ARE EXPECTED TO REMAIN TO THE NORTH OF THE TERMINAL PER WIND
DIRECTION. OTHERWISE...A GENERAL WIND SHIFT WILL TAKE PLACE FROM
THE EAST TO THE SOUTH/SOUTHWEST AS THE FRONT RETREATS SLOWLY TO THE
EAST...WITH A WIND SHIFT TO THE NORTHWEST NEAR THE END OF THE PERIOD
FRI MID/LATE MORNING.
050
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1050 AM MST THU JAN 19 2012
.DISCUSSION...
220 AM MST THU JAN 19 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE EASTERN US...WITH W/NW FLOW
EXTENDING ACROSS THE CENTRAL PART OF THE COUNTRY. AT THE SURFACE A
STRONG COLD FRONT HAS SETTLED OVER THE CWA...WITH A 20F SPREAD IN
TEMPS BETWEEN THE SW PART OF THE CWA AND THE NE.
TODAY-SATURDAY...WITH DRY CONDITIONS EXPECTED THE MAIN FORECAST
CONCERN WILL CONTINUE TO BE TEMPERATURES AS THE PREVIOUSLY MENTIONED
FRONT AND ASSOCIATED BAROCLINIC ZONE LINGERS ACROSS PORTIONS OF
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. 30F SPREAD IN HIGH TEMPS
CURRENTLY FORECAST FROM THE EAST TO THE WEST TODAY...WITH AREAS WEST
OF THE FRONT APPROACHING THE MID 50S...AND EAST OF THE FRONT IN THE
MID/UPPER 20S. BETWEEN THESE EXTREMES IT IS DIFFICULT TO PIN DOWN
HIGH TEMPS CONSIDERING THE EXTREME TEMPERATURE GRADIENT THAT
WILL BE IN PLACE...SO HAVE USED A GENERAL BLEND OF PREVIOUS FORECAST
AND LATEST SHORT-RANGE GUIDANCE. TEMPS WILL BEGIN TO MODERATE SOME
ACROSS EASTERN PARTS OF THE AREA FRIDAY...BEFORE A BACKDOOR COLD
FRONT REINFORCES SHALLOW COLD AIR MASS FRIDAY AFTERNOON/EVENING.
SHALLOW COLD AIR MASS BEGINS TO SCOUR OUT WITH TEMPS MODERATING
AHEAD OF SHORTWAVE TROUGH MOVING TOWARDS THE GREAT BASIN...THOUGH
THERE WILL STILL BE A 15-20F GRADIENT FROM EAST TO WEST.
SATURDAY NIGHT...SHORTWAVE TROUGH MOVES TOWARDS THE CENTRAL ROCKIES
SATURDAY NIGHT...WITH INCREASING LARGE SCALE ASCENT OVER THE CWA
AFTER 06Z. NAM/GFS BOTH ARE WEAKER/QUICKER WITH THIS SYSTEM...AND
KEEP CONDITIONS DRY OVER CWA. ECMWF CONTINUES TO SHOW
STRONGER/WETTER SOLUTION. I WAS HESITANT TO JUMP ON THE WET ECMWF
SOLUTION YET...WITH TIMING/STRENGTH STILL IN QUESTION. WITH THE
AMOUNT OF LIFT PRESENT AND LIMITED MOISTURE ADVECTION I COULDNT RULE
OUT SOME FLURRIES IN THE NORTH...BUT WASNT CONFIDENT ENOUGH TO ADD
DURING THIS CYCLE.
DR
FOR THE PERIOD SUNDAY THROUGH WEDNESDAY...RELATIVELY QUIET WEATHER
EXPECTED THROUGH THE ENTIRE PERIOD. A COLD FRONT WILL MOVE THROUGH
THE REGION MONDAY NIGHT AND TUESDAY...HOWEVER PRECIPITATION CHANCES
APPEAR THEY WILL STAY SOUTH AND EAST OF THE LOCAL FORECAST AREA. IT
WILL BRING A PERIOD OF GUSTY NORTH WINDS...PROBABLY TUESDAY
MORNING....AND COOLER TEMPERATURES TUESDAY AND WEDNESDAY...ALBEIT
STILL ABOVE NORMAL.
024
&&
.AVIATION...
1050 AM MST THU JAN 19 2012
FOR THE 18Z TAFS...ARCTIC COLD CURRENTLY LOCATED NEAR THE KS/CO STATE
LINE. THIS FEATURE WILL CREATE SOME UNCERTAINTY AT KGLD WITH RESPECT
TO TIMING OF WIND SHIFTS...BUT A GENERAL VEER FROM EAST/SOUTHEAST TO
THE SOUTH IS EXPECTED DURING THE AFTERNOON HOURS. ALSO OF NOTE ARE LOW
IFR CIGS CURRENTLY LOCATED JUST TO THE NORTH OF KGLD...BUT THESE LOW
CIGS ARE EXPECTED TO REMAIN TO THE NORTH OF THE TERMINAL PER WIND
DIRECTION. OTHERWISE...A GENERAL WIND SHIFT WILL TAKE PLACE FROM
THE EAST TO THE SOUTH/SOUTHWEST AS THE FRONT RETREATS SLOWLY TO THE
EAST...WITH A WIND SHIFT TO THE NORTHWEST NEAR THE END OF THE PERIOD
FRI MID/LATE MORNING.
050
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
425 AM MST THU JAN 19 2012
.DISCUSSION...
220 AM MST THU JAN 19 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE EASTERN US...WITH W/NW FLOW
EXTENDING ACROSS THE CENTRAL PART OF THE COUNTRY. AT THE SURFACE A
STRONG COLD FRONT HAS SETTLED OVER THE CWA...WITH A 20F SPREAD IN
TEMPS BETWEEN THE SW PART OF THE CWA AND THE NE.
TODAY-SATURDAY...WITH DRY CONDITIONS EXPECTED THE MAIN FORECAST
CONCERN WILL CONTINUE TO BE TEMPERATURES AS THE PREVIOUSLY MENTIONED
FRONT AND ASSOCIATED BAROCLINIC ZONE LINGERS ACROSS PORTIONS OF
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. 30F SPREAD IN HIGH TEMPS
CURRENTLY FORECAST FROM THE EAST TO THE WEST TODAY...WITH AREAS WEST
OF THE FRONT APPROACHING THE MID 50S...AND EAST OF THE FRONT IN THE
MID/UPPER 20S. BETWEEN THESE EXTREMES IT IS DIFFICULT TO PIN DOWN
HIGH TEMPS CONSIDERING THE EXTREME TEMPERATURE GRADIENT THAT
WILL BE IN PLACE...SO HAVE USED A GENERAL BLEND OF PREVIOUS FORECAST
AND LATEST SHORT-RANGE GUIDANCE. TEMPS WILL BEGIN TO MODERATE SOME
ACROSS EASTERN PARTS OF THE AREA FRIDAY...BEFORE A BACKDOOR COLD
FRONT REINFORCES SHALLOW COLD AIR MASS FRIDAY AFTERNOON/EVENING.
SHALLOW COLD AIR MASS BEGINS TO SCOUR OUT WITH TEMPS MODERATING
AHEAD OF SHORTWAVE TROUGH MOVING TOWARDS THE GREAT BASIN...THOUGH
THERE WILL STILL BE A 15-20F GRADIENT FROM EAST TO WEST.
SATURDAY NIGHT...SHORTWAVE TROUGH MOVES TOWARDS THE CENTRAL ROCKIES
SATURDAY NIGHT...WITH INCREASING LARGE SCALE ASCENT OVER THE CWA
AFTER 06Z. NAM/GFS BOTH ARE WEAKER/QUICKER WITH THIS SYSTEM...AND
KEEP CONDITIONS DRY OVER CWA. ECMWF CONTINUES TO SHOW
STRONGER/WETTER SOLUTION. I WAS HESITANT TO JUMP ON THE WET ECMWF
SOLUTION YET...WITH TIMING/STRENGTH STILL IN QUESTION. WITH THE
AMOUNT OF LIFT PRESENT AND LIMITED MOISTURE ADVECTION I COULDNT RULE
OUT SOME FLURRIES IN THE NORTH...BUT WASNT CONFIDENT ENOUGH TO ADD
DURING THIS CYCLE.
DR
FOR THE PERIOD SUNDAY THROUGH WEDNESDAY...RELATIVELY QUIET WEATHER
EXPECTED THROUGH THE ENTIRE PERIOD. A COLD FRONT WILL MOVE THROUGH
THE REGION MONDAY NIGHT AND TUESDAY...HOWEVER PRECIPITATION CHANCES
APPEAR THEY WILL STAY SOUTH AND EAST OF THE LOCAL FORECAST AREA. IT
WILL BRING A PERIOD OF GUSTY NORTH WINDS...PROBABLY TUESDAY
MORNING....AND COOLER TEMPERATURES TUESDAY AND WEDNESDAY...ALBEIT
STILL ABOVE NORMAL.
024
&&
.AVIATION...
425 AM MST THU JAN 19 2012
FOR THE 12Z TAFS...ARCTIC FRONT CONTINUES TO SETTLE INTO THE AREA
FROM THE NORTHEAST. LIGHT WINDS WILL VEER FROM NORTHEAST TO
SOUTHEAST AT KMCK...AND NORTHEAST TO SOUTHWEST AT KGLD THROUGH THIS
AFTERNOON. SCATTERED TO BROKEN HIGH CLOUDS WILL CONTINUE TO STREAM
OVERHEAD. /024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
509 AM CST THU JAN 19 2012
.AVIATION...
FOR THE 12Z TAF ISSUANCE...
AT 9Z A COLD FRONT EXTENDED ACROSS SOUTHWEST KANSAS WITH THE NAM
AND RUC APPEARING TO BE DOING A DECENT JOB WITH THIS SURFACE FRONT
LOCATION. THEY ALSO APPEAR TO BE HANDLING THE TIGHT PRESSURE
GRADIENT/GUSTY WINDS THAT HAD APPEARED AT A FEW OBSERVATION SITES
IN NORTH CENTRAL KANSAS EARLIER THIS MORNING. WILL THEREFORE
CONTINUE TO FOLLOW THE NAM AND RUC SOLUTIONS ON TIMING OF THIS
FRONT/WIND SHIFT AS IT CROSSES THE REMAINDER OF SOUTHWEST KANSAS.
FOLLOWING THE WIND SHIFT A BRIEF PERIOD OF GUSTY WINDS WILL THEN
DEVELOP BUT THESE WINDS WILL START TO SUBSIDE BY MID MORNING AS AN
AREA OF HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM THE
NORTH. SURFACE WINDS AT 10KTS OR LESS ARE THEN EXPECTED THROUGH
THE REMAINDER OF THE AFTERNOON. THE NORTH/NORTHEAST WINDS WILL
GRADUALLY SHIFT TO THE SOUTHEAST EARLY TONIGHT AS OUR SURFACE HIGH
MOVES NORTHEAST OF THE AREA.
BY 06Z FRIDAY BUFR SOUNDINGS SUGGESTING 45KT WINDS WILL DEVELOP
JUST ABOVE THIS COLD LAYER AND THE 0-0.5KM WIND SHEAR IS FORECAST
TO BE AROUND 40KTS. AS A RESULT WILL INTRODUCE A WIND SHEAR GROUP
INTO THE TAFS AT 06Z.-RB
&&
.PREV DISCUSSION... /ISSUED 328 AM CST THU JAN 19 2012/
SYNOPSIS...
PAST EVENING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY
REVEALS A VERY BROAD TROUGH OVER THE EASTERN HALF OF THE COUNTRY
WHILE AN EQUALLY EXTENSIVE RIDGE EXTENDS OVER THE WEST. EMBEDDED
WITHIN THIS FLOW REGIME IS A 140+ KNOT UPPER JET STREAK THAT EXTENDS
FROM THE PACIFIC NORTHWEST REGION INTO THE DEEP SOUTH. CLOSER TO THE
SURFACE, A LARGE RESERVOIR OF ARCTIC AIR ACROSS CANADA IS INVADING
THE NORTHERN PLAINS WITH 00 UTC 850 HPA PLOTS DISPLAYING A LARGE
POCKET OF -30C AIR OVER NORTH DAKOTA INTO EASTERN MONTANA. RECENT
SUBJECTIVE SURFACE ANALYSIS DISPLAYS THE ARCTIC FRONT SINKING
SOUTHWARD OVER KANSAS WITH TEMPERATURES DROPPING QUICKLY INTO THE
SINGLE DIGITS OVER CENTRAL AND NORTHERN NEBRASKA. DETERMINISTIC
MODEL GUIDANCE INITIALIZED AT 00 UTC BUT VALID AT 06 UTC IS RUNNING
AROUND 5 TO 10 DEGREES TOO WARM BEHIND THE FRONT. THIS STRONGLY
INDICATES ANY BOUNDARY LAYER BASED MODEL THERMAL FIELDS ARE TOO WARM
FOR THIS MORNING TO AFTERNOON AS WELL.
DISCUSSION...
DAYS 1-2...
THE UPPER PATTERN WILL CHANGE LITTLE TODAY INTO THE FIRST HALF OF
TONIGHT AS A TROUGH DOMINATES OVER THE EASTERN HALF OF THE COUNTRY
WHILE A RIDGE PREVAILS OVER THE WEST. WITH THE STRONGEST FORCING
REMAINING WELL NORTH OF KANSAS, DRY CONDITIONS WILL CONTINUE OVER
THE CENTRAL PLAINS. NONETHELESS, AGEOSTROPHIC FLOW ASSOCIATED WITH
THE ENTRANCE REGION OF THE AFOREMENTIONED JET STREAK, WILL ALLOW THE
ARCTIC FRONT TO SLIDE SOUTHWARD INTO FAR NORTHERN OKLAHOMA AND
EXTREME SOUTHWEST KANSAS BY MID MORNING. ALTHOUGH THE AIRMASS WILL
REMAIN RELATIVELY SHALLOW WITH 850 HPA TEMPERATURES STAYING
GENERALLY ABOVE 3C TO 5C...STRONG COLD AIR ADVECTION IN THE LOWER
500 METERS WILL KEEP SURFACE TEMPERATURES RELATIVELY COLD TODAY OVER
MOST OF WESTERN AND CENTRAL KANSAS. HOWEVER, THE MAIN QUESTION IS
WHERE THE FRONT WILL EXTEND OVER EXTREME SOUTHWEST KANSAS AS THE
TEMPERATURE GRADIENT WILL BE TIGHT. LOCATIONS SOUTHWEST OF THE
BOUNDARY WILL EXPERIENCE LIGHT WEST WINDS WITH TEMPERATURES IN THE
MID 50S TO LOWER 60S WHILE LOCATIONS A GOOD 60 MILES AWAY FROM THE
FRONT BUT ON THE COOL SIDE OF THE BOUNDARY WILL SEE TEMPERATURES IN
THE MID 20S TO MID 30S. A NARROW 40 TO 50 MILE CORRIDOR WILL ACT AS
A BUFFER ZONE BETWEEN THESE TWO EXTREMES WITH TEMPERATURES IN THE
UPPER 30S TO 40S EXPECTED...BUT WHERE THIS ZONES SETS UP IS SIMPLY A
GUESS AT THIS POINT. WILL AIM FOR A GARDEN CITY TO COLDWATER LINE
WITH HIGHS VARYING FROM THE MID 20S AROUND HAYS, THE UPPER 30S IN
DODGE, AND NEAR 60 AROUND ELKHART.
LATER TONIGHT INTO FRIDAY NIGHT...A SMALL BUT POTENT UPPER WAVE WILL
UNDERCUT THE RIDGE AXIS AND PLOW INTO THE CENTRAL ROCKIES BY LATE
FRIDAY AFTERNOON. ALTHOUGH THE ATMOSPHERE WILL BE TOO DRY FOR THIS
WAVE TO PRODUCE ANY REAL THREAT FOR PRECIPITATION, IT WILL ALLOW A
REINFORCING SHOT OF ARCTIC AIR TO INVADE WESTERN AND CENTRAL KANSAS
BY LATE MORNING TO EARLY AFTERNOON. HOWEVER, IN ADVANCE OF THIS
FRONT PRESSURE FALLS ALONG THE FRONT RANGE REGION WILL BEGIN TO VEER
WINDS AROUND TO A MORE WESTERLY DIRECTION BY SUNRISE ON FRIDAY. THIS
MAY ALLOW FOR SOME MODEST WARM AIR ADVECTION DURING THE EARLY TO MID
MORNING BEFORE COLDER AIR INVADES WESTERN AND CENTRAL KANSAS YET AGAIN.
THE THINKING AS OF NOW IS THAT DOWNSLOPE WESTERLY WINDS WILL SPREAD
AS FAR EAST AS A SCOTT CITY TO COLDWATER LINE BEFORE COLD AIR
ARRIVES IN THE LATE MORNING TO EARLY AFTERNOON. THIS MAY RESULT IN
TEMPERATURES BRIEFLY SPIKING INTO THE MID 40S TO MID 50S WEST OF THE
ABOVE LINE BUT THEN FALLING DURING THE AFTERNOON HOURS. LOCATIONS
EAST OF THIS LINE SHOULD STAY IN THE 30S. OTHERWISE, A COLD EVENING
TO OVERNIGHT WILL PREVAIL AS COLDER AIR SPILLS OVER THE CENTRAL
PLAINS. ANTICIPATE TEMPERATURES DROPPING INTO A 10 TO 20 DEGREE
RANGE AFTER MIDNIGHT.
DAYS 3-7...
A TIGHT BAROCLINIC ZONE WILL ESTABLISH ITSELF ACROSS PORTIONS OF
WESTERN KANSAS ON SATURDAY BETWEEN THE COLDER AIR THAT WILL INVADE
THE STATE FRIDAY NIGHT AND THE DOWNSLOPE WARMING THAT IS ANTICIPATED
TO SPREAD INTO THE AREA FROM THE WEST BY SATURDAY AFTERNOON. THE
CURRENT FORECAST WITH HIGHS ONLY IN THE MID 30S ACROSS PORTIONS OF
NORTH CENTRAL KANSAS STILL APPEARS ON TRACK GIVEN THE LATEST MODELS
SOUNDINGS. FURTHER WEST 850MB TEMPERATURES INDICATING HIGHS NEAR 60
STILL WILL BE POSSIBLE AS THE 925-850MB TEMPERATURES BEGIN TO WARM.
WILL HOWEVER NEED TO MONITOR THE AMOUNT OF HIGHS CLOUDS DURING THE
DAY AS BOTH THE ECMWF AND GFS 300-200MB RELATIVE HUMIDITIES
INCREASES ACROSS WESTERN KANSAS DURING THE AFTERNOON. THIS CLOUD
COVER WILL PRECEDE AN UPPER LEVEL TROUGH WHICH AT 00Z SUNDAY IS
EXPECTED TO BE LOCATED ACROSS UTAH. THIS NEXT SYSTEM WILL QUICKLY
MOVE EAST INTO THE WEST CENTRAL HIGH PLAINS ON SUNDAY AS MID-HIGH
LEVEL MOISTURE CONTINUES TO INCREASE. THIS INCREASE IN MOISTURE
ALONG WITH IMPROVING MID LEVEL INSTABILITY MAY ALSO GIVE RISE TO
SOME VIRGA, MAYBE EVEN A FEW SPRINKLES NEAR THE INTERSTATE 70
CORRIDOR. AT THIS TIME CONFIDENCE IS NOT HIGH ENOUGH YET TO INSERT
MENTION OF LIGHT PRECIPITATION IN OUR NORTH BUT DID INCREASE CLOUD
COVER AND LOWER TEMPERATURES.
BY EARLY NEXT WEEK A SHORT WAVE RIDGE WILL QUICKLY CROSS THE ROCKIES
AND MOVE OUT INTO THE PLAINS AS OUR NEXT PACIFIC UPPER LEVEL TROUGH
STARTS TO WORK ITS WAY EASTWARD ACROSS THE WESTERN UNITED STATES.
ONCE AGAIN MID LEVEL MOISTURE IMPROVES AS 700-500MB LAPSE RATES
INCREASE. THIS WILL ONCE AGAIN BRING AN INCREASE IN CLOUDS AND
POSSIBLY SOME LIGHT PRECIPITATION ON TUESDAY TO PARTS OF SOUTHWEST
KANSAS IF THE GFS IS CORRECT. AGAIN CONFIDENCE IS NOT HIGH ON
PRECIPITATION CHANCES GIVEN THE HEIGHT OF WHERE THE BETTER MOISTURE
RETURN IS ANTICIPATED. HAVE THEREFORE DECIDED TO LEAVE THE SMALL
15-20PERCENT CHANCE OF RAIN GOING FOR OUR SOUTH/SOUTHEAST BUT DID
NOT EXPAND THE CHANCES ANY FURTHER NORTH.
AVIATION...
FOR THE 06Z TAF ISSUANCE...
THERE ISN`T A GREAT DEAL OF CHANGE IN THINKING FOR THIS TAF
ISSUANCE. THE FRONT IS EXPECTED TO MOVE THROUGH HAYS (HYS) AT
07Z...THEN ROUGHLY 0830Z AT DODGE CITY (DDC) AND FINALLY SHORTLY
THEREAFTER AT GARDEN CITY (GCK) AROUND 09Z. THERE WILL BE SEVERAL
HOURS OF GUSTS IN THE LOW 20S KTS...BUT THE WINDS WILL GRADUALLY
DECREASE DURING THE 15-18Z TIME FRAME...WITH A CONTINUE DECREASE
TO LESS THAN 10 KNOTS FOR SOME TIME MIDDAY THROUGH EARLY
AFTERNOON. THE WINDS WILL THEN CONTINUE TO VEER AROUND TO THE
SOUTHEAST LATE IN THE DAY WITH A GRADUAL INCREASE BACK TO AROUND
12 KNOTS OR SLIGHTLY HIGHER IN RESPONSE TO RENEWED LEESIDE
CYCLOGENESIS OVER EASTERN COLORADO. THE PROBABILITY OF STRATUS
DEVELOPMENT IS VERY LOW GIVEN HOW SHALLOW THE ARCTIC AIRMASS IS
AND HOW DRY THE LOWER ATMOSPHERE IS AS WELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 22 48 18 / 0 0 0 0
GCK 41 23 49 17 / 0 0 0 0
EHA 60 35 56 26 / 0 0 0 0
LBL 54 27 57 20 / 0 0 0 0
HYS 26 16 36 11 / 0 0 0 0
P28 39 24 46 19 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99/99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
220 AM MST THU JAN 19 2012
.DISCUSSION...
220 AM MST THU JAN 19 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE EASTERN US...WITH W/NW FLOW
EXTENDING ACROSS THE CENTRAL PART OF THE COUNTRY. AT THE SURFACE A
STRONG COLD FRONT HAS SETTLED OVER THE CWA...WITH A 20F SPREAD IN
TEMPS BETWEEN THE SW PART OF THE CWA AND THE NE.
TODAY-SATURDAY...WITH DRY CONDITIONS EXPECTED THE MAIN FORECAST
CONCERN WILL CONTINUE TO BE TEMPERATURES AS THE PREVIOUSLY MENTIONED
FRONT AND ASSOCIATED BAROCLINIC ZONE LINGERS ACROSS PORTIONS OF
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. 30F SPREAD IN HIGH TEMPS
CURRENTLY FORECAST FROM THE EAST TO THE WEST TODAY...WITH AREAS WEST
OF THE FRONT APPROACHING THE MID 50S...AND EAST OF THE FRONT IN THE
MID/UPPER 20S. BETWEEN THESE EXTREMES IT IS DIFFICULT TO PIN DOWN
HIGH TEMPS CONSIDERING THE EXTREME TEMPERATURE GRADIENT THAT
WILL BE IN PLACE...SO HAVE USED A GENERAL BLEND OF PREVIOUS FORECAST
AND LATEST SHORT-RANGE GUIDANCE. TEMPS WILL BEGIN TO MODERATE SOME
ACROSS EASTERN PARTS OF THE AREA FRIDAY...BEFORE A BACKDOOR COLD
FRONT REINFORCES SHALLOW COLD AIR MASS FRIDAY AFTERNOON/EVENING.
SHALLOW COLD AIR MASS BEGINS TO SCOUR OUT WITH TEMPS MODERATING
AHEAD OF SHORTWAVE TROUGH MOVING TOWARDS THE GREAT BASIN...THOUGH
THERE WILL STILL BE A 15-20F GRADIENT FROM EAST TO WEST.
SATURDAY NIGHT...SHORTWAVE TROUGH MOVES TOWARDS THE CENTRAL ROCKIES
SATURDAY NIGHT...WITH INCREASING LARGE SCALE ASCENT OVER THE CWA
AFTER 06Z. NAM/GFS BOTH ARE WEAKER/QUICKER WITH THIS SYSTEM...AND
KEEP CONDITIONS DRY OVER CWA. ECMWF CONTINUES TO SHOW
STRONGER/WETTER SOLUTION. I WAS HESITANT TO JUMP ON THE WET ECMWF
SOLUTION YET...WITH TIMING/STRENGTH STILL IN QUESTION. WITH THE
AMOUNT OF LIFT PRESENT AND LIMITED MOISTURE ADVECTION I COULDNT RULE
OUT SOME FLURRIES IN THE NORTH...BUT WASNT CONFIDENT ENOUGH TO ADD
DURING THIS CYCLE.
DR
FOR THE PERIOD SUNDAY THROUGH WEDNESDAY...RELATIVELY QUIET WEATHER
EXPECTED THROUGH THE ENTIRE PERIOD. A COLD FRONT WILL MOVE THROUGH
THE REGION MONDAY NIGHT AND TUESDAY...HOWEVER PRECIPITATION CHANCES
APPEAR THEY WILL STAY SOUTH AND EAST OF THE LOCAL FORECAST AREA. IT
WILL BRING A PERIOD OF GUSTY NORTH WINDS...PROBABLY TUESDAY
MORNING....AND COOLER TEMPERATURES TUESDAY AND WEDNESDAY...ALBEIT
STILL ABOVE NORMAL.
024
&&
.AVIATION...
957 PM MST WED JAN 18 2012
FOR THE 06Z TAFS...COLD FRONT HAS PUSHED THROUGH KMCK WITH WINDS
FROM THE NORTHEAST. FRONT WILL MEANDER BETWEEN KMCK AND KGLD THIS
PERIOD WITH WINDS SOUTHWESTERLY TO SOUTHERLY AT KGLD AND
EASTERLY TO SOUTHEASTERLY AT KMCK. MODELS HAVE COME INTO BETTER
AGREEMENT WITH LACK OF STRATUS BEHIND THE FRONT...SO HAVE REMOVED
FROM KMCK FOR THIS MORNING. EVEN THOUGH CLOUDS WILL BE PLENTIFUL
THROUGH THE PERIOD...CEILING WILL BE AOA 120-150.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
958 PM EST FRI JAN 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL CREST OVER THE REGION TONIGHT AS LOW PRESSURE
APPROACHES NEW ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS
OUT TO SEA WELL SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE
WILL BUILD IN FROM THE NORTHWEST SATURDAY NIGHT AND WILL GRADUALLY
SHIFT INTO THE MARITIMES ON SUNDAY. A WARM FRONT WILL LIFT INTO
SOUTHERN NEW ENGLAND ON MONDAY AND WILL BE QUICKLY FOLLOWED BY A
COLD FRONT MONDAY NIGHT. A TRAILING TROUGH OF LOW PRESSURE WILL
SLOWLY MOVE THROUGH NEW ENGLAND ON TUESDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY..CRESTING OVER
THE AREA ON FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
VERY LITTLE CHANGE TO THE CURRENT PACKAGE. WITH LOW TDS AND A VERY
DRY SOUNDING...TEMPS WILL TAKE A NOSEDIVE LATER THIS EVENING AS
THE GRADIENT COLLAPSES. HIGH CLOUDINESS CONTINUES TO RACE EASTWARD
HOWEVER...WHICH WILL HELP READINGS LEVEL OFF LATER TONIGHT. THIS
MAY REQUIRE MIN TEMPERATURES TO BE NUDGED UPWARDS FOR THE NEXT
PACKAGE UPDATE.
SURFACE ANALYSIS AT 01Z SHOWING A WEAK AND ELONGATED AREA OF LOW
PRESSURE APPROACHING THE WESTERN TENNESSEE BORDER. BEST PRESSURE
FALLS HAVE SHIFTED INTO NORTHERN WEST VIRGINA THIS HOUR...WITH THE
SYSTEM EXPECTED TO SHIFT UNDERNEATH NEW ENGLAND.
LATEST 3 KM HRRR BRINGS SNOW TO THE FAR WESTERN REACHES OF NH BY
08Z...REACHING MAINE BY AROUND 11Z WHICH APPEARS TOO FAST
CONSIDERING OUR DRY/ARCTIC AIR IN PLACE. WILL DELAY THE ONSET OF
LIKELY POPS 2-3 HOURS LATER THAN THIS.
WILL BE INCREASING POPS OVER SOUTH-CENTRAL AREAS INTO THE LOW
LIKELY CATEGORY FOR TOMORROW. THIS WILL BETTER MATCH THE
ACCUMULATING SNOWS (ALBIET LIGHT) THE WE ARE CURRENTLY
FORECASTING...WHICH IS A DUSTING TO AN INCH. OVER SOUTHERNMOST
AREAS...NEAR THE MASS BORDER...EXPECT 1-3 INCHES...WITH POSSIBLY
LOCALLY HIGHER AMOUNTS.
PREV DISC...
CLEAR AND VERY COLD FIRST HALF OF THE NIGHT AS HIGH PRESSURE
CRESTS OVER THE REGION...BUT CLOUDS WILL QUICKLY PUSH BACK INTO
THE REGION AS LOW PRESSURE APPROACHES NEW ENGLAND FROM THE
SOUTHWEST. CLOUDS WILL GRADUALLY LOWER AND THICKEN FROM WEST TO
EAST AND SOME LIGHT SNOW OR SNOW SHOWERS WILL EDGE INTO THE
CONNECTICUT VALLEY AND SOUTHERN NEW HAMPSHIRE TOWARD DAYBREAK. NOT
LOOKING FOR MUCH IN THE WAY OF ACCUMULATION THROUGH 12Z WITH JUST
A DUSTING LIKELY IN FAR SOUTHWEST ZONES. EXPECTING LOWS 5 TO 15
BELOW IN THE NORTH AND 5 BELOW TO 5 ABOVE IN THE SOUTH.
&&
.SHORT TERM /SATURDAY NIGHT/...
LIGHT SNOW WILL PERSIST IN SOUTHERN ZONES MAINLY DURING THE MORNING
HOURS BEFORE TAPERING OFF IN THE AFTERNOON. MODELS NOT PUTTING
OUT MUCH IN THE WAY OF QPF WITH MOST AREAS SEEING A TENTH OF AN INCH
OR LESS BUT A DECENT FLUFF FACTOR MAY PRODUCE UP TO TWO INCHES OF
SNOW IN FAR SOUTHERN NEW HAMPSHIRE. LOOKING FOR AROUND AN INCH OR
LESS ACROSS THE REMAINDER OF THE FORECAST AREA. EXPECT PARTIAL
CLEARING FROM NORTHWEST TO SOUTHEAST LATER IN THE AFTERNOON AS
LOW PRESSURE HEADS OUT TO SEA SOUTH OF NEW ENGLAND. HIGH
TEMPERATURES WON`T GET PAST THE TEENS IN THE NORTH AND MID TEENS
TO LOWER 20S IN THE SOUTH.
COLD HIGH PRESSURE WILL BUILD SOUTHEAST FROM CANADA SATURDAY NIGHT
CLEARING SKIES AND ALLOWING TEMPERATURES TO PLUMMET ONCE AGAIN.
LOOKING FOR LOWS 5 TO 15 BELOW IN THE NORTH AND 5 BELOW TO 10
ABOVE IN THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGH PRES BRINGS FAIR WX SUNDAY. LOW PRES AND A TRAILING CD FRONT
APPROACH FROM THE W SUNDAY NGT AS A WRM FNT EXTENDING E FROM THE
LOW HAS ANOTHER WEAKER LOW FORM ALONG THE COAST. AS THIS SYSTEM
MOVES TOWARD NEW ENGLAND THE COASTAL LOW WILL COMBINE WITH THE
HIGH TO THE NE TO HELP KEEP COLDER AIR IN OVER THE FCST AREA
ESPECIALLY WHEN THE COASTAL FNT FORMS.
GRADUALLY THOUGH THE WRM AIR STREAMING NE IN AN INCREASINGLY
STRONGER S SW FLOW ALOFT EVENTUALLY ERODES THE CD AIR FORCING SN
TO CHANGE TO MIX THEN TO RA FROM SW TO NE ACROSS THE FCST AREA. SN
AMOUNTS MAY BE LIMITED TO MORE NRN AND NE AREAS AND AMOUNTS, IF
ANY, WOULD LIKELY BE MINIMAL. ICING FROM SLEET AND FREEZING RA MAY
BE MORE OF AN ISSUE DEPENDING ON HOW LONG THE CD AIR HOLDS IN AT
LOW LEVELS AND AT THE SFC.
MODELS VARY ON QPF AMOUNTS BUT AN INCH OF QPF THRU THE EVENT
APPEARS VERY PSBL WITH A MAJORITY OF IT LIKELY FALLING AS RA. THE
GFS IS SHOWING EVEN HIGHER QPF WHILE NAM AND ECMWF SHOW
CONSIDERABLY LESS..AT LEAST THRU 00Z TUESDAY.
THE CD FNT SWEEPS THRU MONDAY NGT WITH PRCP ENDING OR AT LEAST
TAPERING OFF FROM SW TO NE. ON TUESDAY COLDER AIR FILTERS IN AND
AN UPR LEVEL TROF ALONG WITH UPSLOPE LOW LVL FLOW WILL HELP
PRODUCE -SHSN ACTIVITY..ESPECIALLY ACROSS THE N/MT ZONES.
HIGH PRES BRINGS FAIR WX WEDNESDAY. A WEAK UPR LVL SHORT WAVE
TROF MOVING THRU IN AN UPR LVL NW FLOW MAY BRING THE CHC OF SOME
-SHSN ON THURSDAY...MAINLY ACROSS MORE NRN AND NE AREAS. HIGH PRES
TRIES TO BUILD IN BRIEFLY FOR FRIDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
THRU SUNDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TONIGHT WITH SOME AREAS OF MVFR CEILINGS/VSBY
DEVELOPING OVER SOUTHERN NEW HAMPSHIRE TOWARD MORNING. MVFR/IFR
CEILINGS AND VSBY MAINLY IN SOUTHERN AREAS ON SATURDAY...IMPROVING
IN THE AFTERNOON. VFR SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...IFR OR LIFR IN MIXED PRCP
DEVELOPING SUNDAY NGT...CONTINUING THRU MONDAY AND ENDING MONDAY
NGT AS IT TRANSITIONS OVER TO RA.
&&
.MARINE...
SHORT TERM...SCA IN EFFECT THROUGH EARLY EVENING. SCA`S WILL LIKELY
BE NEEDED LATE SATURDAY AFTERNOON THROUGH MIDNIGHT SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...WINDS AND SEAS INCREASE ON
MONDAY...REACHING SCA LEVELS WITH WINDS POSSIBLY REACHING GALE
FORCE...AHEAD OF LOW PRES AND A TRAILING CD FNT. CONDITIONS
BRIEFLY LET UP LATE MONDAY NGT AS THE CD FNT MOVES THRU...ONLY TO
INCREASE TO SCA OR GALE FORCE TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
908 PM EST FRI JAN 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL CREST OVER THE REGION TONIGHT AS LOW PRESSURE
APPROACHES NEW ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS
OUT TO SEA WELL SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE
WILL BUILD IN FROM THE NORTHWEST SATURDAY NIGHT AND WILL GRADUALLY
SHIFT INTO THE MARITIMES ON SUNDAY. A WARM FRONT WILL LIFT INTO
SOUTHERN NEW ENGLAND ON MONDAY AND WILL BE QUICKLY FOLLOWED BY A
COLD FRONT MONDAY NIGHT. A TRAILING TROUGH OF LOW PRESSURE WILL
SLOWLY MOVE THROUGH NEW ENGLAND ON TUESDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY..CRESTING OVER
THE AREA ON FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
VERY LITTLE CHANGE TO THE CURRENT PACKAGE. WITH LOW TDS AND A VERY
DRY SOUNDING...TEMPS WILL TAKE A NOSEDIVE LATER THIS EVENING AS
THE GRADIENT COLLAPSES. HIGH CLOUDINESS CONTINUES TO RACE EASTWARD
HOWEVER...WHICH WILL HELP READINGS LEVEL OFF LATER TONIGHT. THIS
MAY REQUIRE MIN TEMPERATURES TO BE NUDGED UPWARDS FOR THE NEXT
PACKAGE UPDATE.
SURFACE ANALYSIS AT 01Z SHOWING A WEAK AND ELONGATED AREA OF LOW
PRESSURE APPROACHING THE WESTERN TENNESSEE BORDER. BEST PRESSURE
FALLS HAVE SHIFTED INTO NORTHERN WEST VIRGINA THIS HOUR...WITH THE
SYSTEM EXPECTED TO SHIFT UNDERNEATH NEW ENGLAND.
LATEST 3 KM HRRR BRINGS SNOW TO THE FAR WESTERN REACHES OF NH BY
08Z...REACHING MAINE BY AROUND 11Z WHICH APPEARS TOO FAST
CONSIDERING OUR DRY/ARCTIC AIR IN PLACE. WILL DELAY THE ONSET OF
LIKELY POPS 2-3 HOURS LATER THAN THIS.
WILL BE INCREASING POPS OVER SOUTH-CENTRAL AREAS INTO THE LOW
LIKELY CATEGORY FOR TOMORROW. THIS WILL BETTER MATCH THE
ACCUMULATING SNOWS (ALBIET LIGHT) THE WE ARE CURRENTLY
FORECASTING...WHICH IS A DUSTING TO AN INCH. OVER SOUTHERNMOST
AREAS...NEAR THE MASS BORDER...EXPECT 1-3 INCHES...WITH POSSIBLY
LOCALLY HIGHER AMOUNTS.
PREV DISC...
CLEAR AND VERY COLD FIRST HALF OF THE NIGHT AS HIGH PRESSURE
CRESTS OVER THE REGION...BUT CLOUDS WILL QUICKLY PUSH BACK INTO
THE REGION AS LOW PRESSURE APPROACHES NEW ENGLAND FROM THE
SOUTHWEST. CLOUDS WILL GRADUALLY LOWER AND THICKEN FROM WEST TO
EAST AND SOME LIGHT SNOW OR SNOW SHOWERS WILL EDGE INTO THE
CONNECTICUT VALLEY AND SOUTHERN NEW HAMPSHIRE TOWARD DAYBREAK. NOT
LOOKING FOR MUCH IN THE WAY OF ACCUMULATION THROUGH 12Z WITH JUST
A DUSTING LIKELY IN FAR SOUTHWEST ZONES. EXPECTING LOWS 5 TO 15
BELOW IN THE NORTH AND 5 BELOW TO 5 ABOVE IN THE SOUTH.
&&
.SHORT TERM /SATURDAY NIGHT/...
LIGHT SNOW WILL PERSIST IN SOUTHERN ZONES MAINLY DURING THE MORNING
HOURS BEFORE TAPERING OFF IN THE AFTERNOON. MODELS NOT PUTTING
OUT MUCH IN THE WAY OF QPF WITH MOST AREAS SEEING A TENTH OF AN INCH
OR LESS BUT A DECENT FLUFF FACTOR MAY PRODUCE UP TO TWO INCHES OF
SNOW IN FAR SOUTHERN NEW HAMPSHIRE. LOOKING FOR AROUND AN INCH OR
LESS ACROSS THE REMAINDER OF THE FORECAST AREA. EXPECT PARTIAL
CLEARING FROM NORTHWEST TO SOUTHEAST LATER IN THE AFTERNOON AS
LOW PRESSURE HEADS OUT TO SEA SOUTH OF NEW ENGLAND. HIGH
TEMPERATURES WON`T GET PAST THE TEENS IN THE NORTH AND MID TEENS
TO LOWER 20S IN THE SOUTH.
COLD HIGH PRESSURE WILL BUILD SOUTHEAST FROM CANADA SATURDAY NIGHT
CLEARING SKIES AND ALLOWING TEMPERATURES TO PLUMMET ONCE AGAIN.
LOOKING FOR LOWS 5 TO 15 BELOW IN THE NORTH AND 5 BELOW TO 10
ABOVE IN THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGH PRES BRINGS FAIR WX SUNDAY. LOW PRES AND A TRAILING CD FRONT
APPROACH FROM THE W SUNDAY NGT AS A WRM FNT EXTENDING E FROM THE
LOW HAS ANOTHER WEAKER LOW FORM ALONG THE COAST. AS THIS SYSTEM
MOVES TOWARD NEW ENGLAND THE COASTAL LOW WILL COMBINE WITH THE
HIGH TO THE NE TO HELP KEEP COLDER AIR IN OVER THE FCST AREA
ESPECIALLY WHEN THE COASTAL FNT FORMS.
GRADUALLY THOUGH THE WRM AIR STREAMING NE IN AN INCREASINGLY
STRONGER S SW FLOW ALOFT EVENTUALLY ERODES THE CD AIR FORCING SN
TO CHANGE TO MIX THEN TO RA FROM SW TO NE ACROSS THE FCST AREA. SN
AMOUNTS MAY BE LIMITED TO MORE NRN AND NE AREAS AND AMOUNTS, IF
ANY, WOULD LIKELY BE MINIMAL. ICING FROM SLEET AND FREEZING RA MAY
BE MORE OF AN ISSUE DEPENDING ON HOW LONG THE CD AIR HOLDS IN AT
LOW LEVELS AND AT THE SFC.
MODELS VARY ON QPF AMOUNTS BUT AN INCH OF QPF THRU THE EVENT
APPEARS VERY PSBL WITH A MAJORITY OF IT LIKELY FALLING AS RA. THE
GFS IS SHOWING EVEN HIGHER QPF WHILE NAM AND ECMWF SHOW
CONSIDERABLY LESS..AT LEAST THRU 00Z TUESDAY.
THE CD FNT SWEEPS THRU MONDAY NGT WITH PRCP ENDING OR AT LEAST
TAPERING OFF FROM SW TO NE. ON TUESDAY COLDER AIR FILTERS IN AND
AN UPR LEVEL TROF ALONG WITH UPSLOPE LOW LVL FLOW WILL HELP
PRODUCE -SHSN ACTIVITY..ESPECIALLY ACROSS THE N/MT ZONES.
HIGH PRES BRINGS FAIR WX WEDNESDAY. A WEAK UPR LVL SHORT WAVE
TROF MOVING THRU IN AN UPR LVL NW FLOW MAY BRING THE CHC OF SOME
-SHSN ON THURSDAY...MAINLY ACROSS MORE NRN AND NE AREAS. HIGH PRES
TRIES TO BUILD IN BRIEFLY FOR FRIDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
THRU SUNDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TONIGHT WITH SOME AREAS OF MVFR CEILINGS/VSBY
DEVELOPING OVER SOUTHERN NEW HAMPSHIRE TOWARD MORNING. MVFR/IFR
CEILINGS AND VSBY MAINLY IN SOUTHERN AREAS ON SATURDAY...IMPROVING
IN THE AFTERNOON. VFR SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...IFR OR LIFR IN MIXED PRCP
DEVELOPING SUNDAY NGT...CONTINUING THRU MONDAY AND ENDING MONDAY
NGT AS IT TRANSITIONS OVER TO RA.
&&
.MARINE...
SHORT TERM...SCA IN EFFECT THROUGH EARLY EVENING. SCA`S WILL LIKELY
BE NEEDED LATE SATURDAY AFTERNOON THROUGH MIDNIGHT SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...WINDS AND SEAS INCREASE ON
MONDAY...REACHING SCA LEVELS WITH WINDS POSSIBLY REACHING GALE
FORCE...AHEAD OF LOW PRES AND A TRAILING CD FNT. CONDITIONS
BRIEFLY LET UP LATE MONDAY NGT AS THE CD FNT MOVES THRU...ONLY TO
INCREASE TO SCA OR GALE FORCE TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
820 PM EST FRI JAN 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL CREST OVER THE REGION TONIGHT AS LOW PRESSURE
APPROACHES NEW ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS
OUT TO SEA WELL SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE
WILL BUILD IN FROM THE NORTHWEST SATURDAY NIGHT AND WILL GRADUALLY
SHIFT INTO THE MARITIMES ON SUNDAY. A WARM FRONT WILL LIFT INTO
SOUTHERN NEW ENGLAND ON MONDAY AND WILL BE QUICKLY FOLLOWED BY A
COLD FRONT MONDAY NIGHT. A TRAILING TROUGH OF LOW PRESSURE WILL
SLOWLY MOVE THROUGH NEW ENGLAND ON TUESDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY..CRESTING OVER
THE AREA ON FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
VERY LITTLE CHANGE TO THE CURRENT PACKAGE. WITH LOW TDS AND A VERY
DRY SOUNDING...TEMPS WILL TAKE A NOSEDIVE LATER THIS EVENING AS
THE GRADIENT COLLAPSES.
LATEST 3 KM HRRR BRINGS SNOW TO THE FAR WESTERN REACHES OF NH BY
08Z...REACHING MAINE BY AROUND 11Z WHICH APPEARS TOO FAST
CONSIDERING OUR DRY/ARCTIC AIR IN PLACE.
WILL BE INCREASING POPS OVER SOUTH-CENTRAL AREAS INTO THE LOW
LIKELY CATEGORY FOR TOMORROW. THIS WILL BETTER MATCH THE
ACCUMULATING SNOWS (ALBIET LIGHT) THE WE ARE CURRENTLY
FORECASTING...WHICH IS A DUSTING TO AN INCH.
PREV DISC...
CLEAR AND VERY COLD FIRST HALF OF THE NIGHT AS HIGH PRESSURE
CRESTS OVER THE REGION...BUT CLOUDS WILL QUICKLY PUSH BACK INTO
THE REGION AS LOW PRESSURE APPROACHES NEW ENGLAND FROM THE
SOUTHWEST. CLOUDS WILL GRADUALLY LOWER AND THICKEN FROM WEST TO
EAST AND SOME LIGHT SNOW OR SNOW SHOWERS WILL EDGE INTO THE
CONNECTICUT VALLEY AND SOUTHERN NEW HAMPSHIRE TOWARD DAYBREAK. NOT
LOOKING FOR MUCH IN THE WAY OF ACCUMULATION THROUGH 12Z WITH JUST
A DUSTING LIKELY IN FAR SOUTHWEST ZONES. EXPECTING LOWS 5 TO 15
BELOW IN THE NORTH AND 5 BELOW TO 5 ABOVE IN THE SOUTH.
&&
.SHORT TERM /SATURDAY NIGHT/...
LIGHT SNOW WILL PERSIST IN SOUTHERN ZONES MAINLY DURING THE MORNING
HOURS BEFORE TAPERING OFF IN THE AFTERNOON. MODELS NOT PUTTING
OUT MUCH IN THE WAY OF QPF WITH MOST AREAS SEEING A TENTH OF AN INCH
OR LESS BUT A DECENT FLUFF FACTOR MAY PRODUCE UP TO TWO INCHES OF
SNOW IN FAR SOUTHERN NEW HAMPSHIRE. LOOKING FOR AROUND AN INCH OR
LESS ACROSS THE REMAINDER OF THE FORECAST AREA. EXPECT PARTIAL
CLEARING FROM NORTHWEST TO SOUTHEAST LATER IN THE AFTERNOON AS
LOW PRESSURE HEADS OUT TO SEA SOUTH OF NEW ENGLAND. HIGH
TEMPERATURES WON`T GET PAST THE TEENS IN THE NORTH AND MID TEENS
TO LOWER 20S IN THE SOUTH.
COLD HIGH PRESSURE WILL BUILD SOUTHEAST FROM CANADA SATURDAY NIGHT
CLEARING SKIES AND ALLOWING TEMPERATURES TO PLUMMET ONCE AGAIN.
LOOKING FOR LOWS 5 TO 15 BELOW IN THE NORTH AND 5 BELOW TO 10
ABOVE IN THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGH PRES BRINGS FAIR WX SUNDAY. LOW PRES AND A TRAILING CD FRONT
APPROACH FROM THE W SUNDAY NGT AS A WRM FNT EXTENDING E FROM THE
LOW HAS ANOTHER WEAKER LOW FORM ALONG THE COAST. AS THIS SYSTEM
MOVES TOWARD NEW ENGLAND THE COASTAL LOW WILL COMBINE WITH THE
HIGH TO THE NE TO HELP KEEP COLDER AIR IN OVER THE FCST AREA
ESPECIALLY WHEN THE COASTAL FNT FORMS.
GRADUALLY THOUGH THE WRM AIR STREAMING NE IN AN INCREASINGLY
STRONGER S SW FLOW ALOFT EVENTUALLY ERODES THE CD AIR FORCING SN
TO CHANGE TO MIX THEN TO RA FROM SW TO NE ACROSS THE FCST AREA. SN
AMOUNTS MAY BE LIMITED TO MORE NRN AND NE AREAS AND AMOUNTS, IF
ANY, WOULD LIKELY BE MINIMAL. ICING FROM SLEET AND FREEZING RA MAY
BE MORE OF AN ISSUE DEPENDING ON HOW LONG THE CD AIR HOLDS IN AT
LOW LEVELS AND AT THE SFC.
MODELS VARY ON QPF AMOUNTS BUT AN INCH OF QPF THRU THE EVENT
APPEARS VERY PSBL WITH A MAJORITY OF IT LIKELY FALLING AS RA. THE
GFS IS SHOWING EVEN HIGHER QPF WHILE NAM AND ECMWF SHOW
CONSIDERABLY LESS..AT LEAST THRU 00Z TUESDAY.
THE CD FNT SWEEPS THRU MONDAY NGT WITH PRCP ENDING OR AT LEAST
TAPERING OFF FROM SW TO NE. ON TUESDAY COLDER AIR FILTERS IN AND
AN UPR LEVEL TROF ALONG WITH UPSLOPE LOW LVL FLOW WILL HELP
PRODUCE -SHSN ACTIVITY..ESPECIALLY ACROSS THE N/MT ZONES.
HIGH PRES BRINGS FAIR WX WEDNESDAY. A WEAK UPR LVL SHORT WAVE
TROF MOVING THRU IN AN UPR LVL NW FLOW MAY BRING THE CHC OF SOME
-SHSN ON THURSDAY...MAINLY ACROSS MORE NRN AND NE AREAS. HIGH PRES
TRIES TO BUILD IN BRIEFLY FOR FRIDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
THRU SUNDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TONIGHT WITH SOME AREAS OF MVFR CEILINGS/VSBY
DEVELOPING OVER SOUTHERN NEW HAMPSHIRE TOWARD MORNING. MVFR/IFR
CEILINGS AND VSBY MAINLY IN SOUTHERN AREAS ON SATURDAY...IMPROVING
IN THE AFTERNOON. VFR SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...IFR OR LIFR IN MIXED PRCP
DEVELOPING SUNDAY NGT...CONTINUING THRU MONDAY AND ENDING MONDAY
NGT AS IT TRANSITIONS OVER TO RA.
&&
.MARINE...
SHORT TERM...SCA IN EFFECT THROUGH EARLY EVENING. SCA`S WILL LIKELY
BE NEEDED LATE SATURDAY AFTERNOON THROUGH MIDNIGHT SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...WINDS AND SEAS INCREASE ON
MONDAY...REACHING SCA LEVELS WITH WINDS POSSIBLY REACHING GALE
FORCE...AHEAD OF LOW PRES AND A TRAILING CD FNT. CONDITIONS
BRIEFLY LET UP LATE MONDAY NGT AS THE CD FNT MOVES THRU...ONLY TO
INCREASE TO SCA OR GALE FORCE TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
501 PM EST THU JAN 19 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE EAST THROUGH NEW ENGLAND AND THE GULF
OF MAINE OVERNIGHT. LOW PRESSURE WILL SHIFT INTO THE MARITIMES ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. HIGH PRESSURE
WILL SHIFT EAST FRIDAY NIGHT AS WEAK LOW PRESSURE APPROACHES NEW
ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS OUT TO SEA
SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE WILL BUILD IN FROM
THE NORTHWEST SATURDAY NIGHT AND SUNDAY. LOW PRESSURE LIFTING
NORTHEAST OUT OF THE NORTHERN GREAT LAKES WILL DRIVE A COLD FRONT
TOWARD NEW ENGLAND ON MONDAY. THE FRONT WILL CROSS THE AREA MONDAY
NIGHT WITH A TRAILING TROUGH OF LOW PRESSURE MOVING THROUGH THE
REGION ON TUESDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST
ON WEDNESDAY. LOW PRESSURE WILL PASS SOUTH OF NEW ENGLAND ON
THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
ALSO...LATEST HRRR MODEL UPDATE HAS A GOOD HANDLE WITH OCEAN
EFFECT SNOW SHOWERS ENTERING ROCKINGHAM AND YORK COUNTIES THIS
HOUR. HAVE UPPED POPS QUITE A BIT FOR THIS AREA TO ACCOUNT FOR
THIS LOCAL PCPN. -SHSN WILL SPREAD NORTHWARD IN THE NEXT HOUR OR
TWO INTO THE PWM AND POSSIBLY THE NHZ AREAS.
HAVE UPDATED GRIDS TO INCREASE CLOUD COVER OVERNIGHT TO OVERCAST
CONDITIONS WITH ADVISORIES IN EFFECT. REST OF THE GRIDS WILL
REMAIN RELATIVELY UNCHANGED WITH ADVISORIES CONTINUING FOR THE ERN
HALF OF THE FORECAST AREA.
PREV DISC...
WEAK LOW PRESSURE APPROACHING FROM THE WEST WILL BRING A
BRIEF ROUND OF LIGHT TO MODERATE SNOW TO THE REGION OVERNIGHT. LOW
PRESSURE STILL FORECAST TO RE-DEVELOP OVER SOUTHERN NEW ENGLAND
AND MOVE INTO THE GULF OF MAINE BUT MODELS NOT AS STRONG WITH THIS
SYSTEM TODAY AND QPF FOR THE EVENT HAS DROPPED OFF SOMEWHAT.
EXPECT SNOW TO PUSH INTO THE CONNECTICUT VALLEY EARLY THIS EVENING
AND QUICKLY OVER-SPREAD THE REMAINDER OF THE FORECAST AREA THROUGH
MIDNIGHT. WILL STILL BE GOING WITH THE CURRENT ADVISORIES FOR
SOUTHERN AND COASTAL MAINE EXCLUDING YORK COUNTY FOR THE OVERNIGHT
HOURS. HAVE NOT CHANGED ACCUMULATIONS MUCH FROM YESTERDAY WITH 2
TO 4 INCHES OF ACCUMULATION EXPECTED ACROSS MUCH OF NEW HAMPSHIRE
AND EXTREME SOUTHWEST MAINE. REMAINDER OF SOUTHERN AND COASTAL
MAINE WILL SEE 3 TO 6 INCHES OF SNOWFALL THROUGH EARLY FRIDAY
MORNING. EXPECT SNOW TO QUICKLY END IN NEW HAMPSHIRE AND SOUTHWEST
MAINE BEFORE DAYBREAK ON FRIDAY. SHOULD BE A MUCH WARMER NIGHT
WITH TEMPS IN THE LOWER TO MID TEENS IN THE NORTH AND MID TEENS TO
LOWER 20S IN THE SOUTH.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRINGING CLEARING
SKIES AND MOSTLY SUNNY WEATHER TO MOST OF THE AREA ON FRIDAY.
SHOULD SEE MORNING CLOUDS CLEARING OUT OF THE MOUNTAINS AND FAR
EASTERN ZONES BY NOON. EXPECT TEMPS TO RANGE THROUGH THE TEENS IN
THE NORTH AND THROUGH THE 20S AND LOWER 30S IN THE SOUTH.
MID HIGH LEVEL CLOUDINESS WILL BE ON THE INCREASE FRIDAY NIGHT AS
WEAK OVER-RUNNING PATTERN SHIFTS INTO THE NORTHEAST AHEAD OF LOW
PRESSURE MOVING INTO THE MID ATLANTIC STATES. WILL INTRODUCE
LOW CHANCE POPS INTO SOUTHERN NEW HAMPSHIRE AFTER MIDNIGHT BUT
EXPECT LITTLE IF ANY ACCUMULATION THROUGH SATURDAY MORNING. LOW
TEMPS WILL RANGE FROM ZERO TO 10 BELOW IN THE NORTH AND 5 TO 15
ABOVE IN THE SOUTH.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MODELS TRACK WEAK SFC LOW OFF THE MID ATLANTIC COAST E AND OUT TO
SEA ON SATURDAY. THIS WILL PRODUCE -SN ACROSS THE FCST AREA WITH
LGT ACCUMULATIONS PSBL. HIGHEST CHC OF SN AND HIGHEST
ACCUMULATIONS OVER MORE SRN AREAS CLOSER TO THE LOW WITH LOWEST
CHC AND ACCUMULATION TO THE N. VERTICAL TEMP PROFILE CD ENOUGH TO
SUPPORT ALL SN FOR THIS EVENT.
THE LOW MOVES OUT TO SEA FAIRLY QUICKLY WITH -SN ENDING FROM W TO E
IN THE AFTERNOON. HIGH PRES FOLLOWS WITH FAIR WX SATURDAY NGT AND
SUNDAY. THE HIGH MOVES OUT TO THE E SUNDAY NGT AS THE UPR LVL
RIDGE CRESTS ALONG THE E COAST. A STRONG UPR LVL CUTOFF SYSTEM
OVER THE UPPER MID WEST CREATES A FAIRLY STRONG SFC LOW OVER THE
GREAT LAKES THAT WILL TRACK SLOWLY E WITH A TRAILING CD FNT
EXTENDING TO THE S. AHEAD OF THIS SYSTEM INCREASING S SW FLOW FROM
SFC TO H5 BRINGS IN MUCH WARMER AIR ALOFT AND EVENTUALLY TO THE
SFC AS PRCP EVENTUALLY MOVES IN LATE SUNDAY NGT AND MONDAY. MAY BE
SOME -SN OR MIXED SN AND ICE TO BEGIN WITH BUT GRADUALLY PRPC
CHANGES OVER TO RA FOR MONDAY AND MONDAY NGT THOUGH SOME -FZRA
STILL PSBL ACROSS THE NRN TIER OF ZONES WHERE IT WILL TAKE THE
LONGEST TO SCOUR OUT THE CD AIR AT THE SFC.
THE CD FNT MOVES THRU BY TUESDAY MORNING WITH COLDER AIR FOLLOWING
THE FNT AS TEMPS LIKELY TO FALL DURING THE DAY AFTER MILD PREDAWN
READINGS. A SECONDARY UPR LVL TROF MOVES THRU WHICH MAY PRODUCE A
FEW -SHSN BUT THE N/MT ZONES HAVE THE BEST CHC OF -SHSN DUE TO
DEVELOPING UPSLOPE FLOW IN THE CD AIR ADVECTION BEHIND THE FNT.
HIGH PRES BRINGS FAIR WX WEDNESDAY FOLLOWED BY A FAST MOVING SFC
LOW THAT WILL TRACK TO OUR S BRINGING THE CHC OF -SN WEDNESDAY NGT
AND THURSDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SATURDAY
THRU SATURDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST...
EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN
TEMPS.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...MVFR/IFR CEILINGS AND VSBY DEVELOPING THIS
EVENING...IMPROVING TO VFR ON FRIDAY. VFR FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...IFR PSBL WITH -SN SATURDAY.
IFR OR LIFR PSBL WITH MIXED PRCP DEVELOPING LATE SUNDAY NGT AND
CONTINUING THRU MONDAY.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY IN EFFECT THIS EVENING THROUGH FRIDAY.
LONG TERM /SATURDAY THROUGH MONDAY/...CONDITIONS BELOW SCA LEVELS
SATURDAY THRU SUNDAY NGT...THEN INCREASE TO SCA LEVELS OR PSBL
GALES MONDAY INTO MONDAY NGT IN STRENGTHEN S SW FLOW AHEAD OF THE
CD FNT. WINDS SHIFT TO THE W AS THE FNT MOVES OUT TO SEA AND CONT AT
SCA OR PSBL GALE LEVELS ON TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
FRIDAY FOR MEZ012>014-019>022-024>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
FRIDAY FOR ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
424 PM EST THU JAN 19 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF ACCUMULATING SNOW
EARLY TONIGHT. HIGH PRESSURE WILL THEN ALLOW FOR A BRIEF BREAK
FROM WINTRY PRECIPITATION EARLY ON FRIDAY. LOW PRESSURE, MOVING
NORTHEAST FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, BRINGING A
WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW AS A TROUGH MOVES ACROSS THE EASTERN GREAT LAKES.
AT THE SURFACE, A 998MB LOW IS LOCATED NORTHEAST OF MICHIGAN. A COLD
FRONT EXTENDS SOUTH OF THIS FEATURE INTO OHIO. AHEAD OF THE
FRONT, AN AREA OF LIGHT SNOW IS PUSHING INTO EASTERN OHIO AND
WESTERN PA. THE SNOW INCREASES IN INTENSITY CLOSER TO THE FRONT,
WITH MODERATE SNOW REPORTED A FEW OBS UPSTREAM IN NORTHWEST OHIO.
THIS EVENING...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST TOWARD THE
AREA, WITH THE RUC/HRRR WIND SHIFT SUPPORTING THE FRONT REACHING A
ZANESVILLE-NEW PHILADELPHIA-FRANKLIN LINE BY 00Z. LIGHT SNOW WILL
INCREASE IN INTENSITY AT TIMES, REDUCING VISIBILITIES THIS
EVENING. A FACTOR IN THE SNOWFALL ACCUMULATION AT LEAST INITIALLY
WILL BE SURFACE TEMPS, WITH AREAS SOUTH OF I-70 IN THE MID TO
UPPER 30S. THIS WILL LIMIT SNOWFALL ACCUMULATION THERE INITIALLY.
THUS FORECAST INTO THE EARLY EVENING IS FOR AROUND AN INCH NORTH
OF I-70 AND FOR A HALF OF AN INCH OR LESS SOUTHWARD.
TONIGHT...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST ACROSS THE
UPPER OHIO VALLEY, PUSHING SOUTHEAST OF THE RIDGES BY 03Z FRI.
THE BEST CHANCE FOR SNOW ACCUMULATION AND POTENTIALLY HAZARDOUS
TRAVEL WILL BE AROUND SUNSET THROUGH MIDNIGHT AS SNOW PUSHES ACROSS THE
AREA. SNOW WILL BEGIN TO TAPER OFF BEHIND THE FRONT WITH JUST A
FEW LINGERING SNOW SHOWERS ALONG THE I-80 CORRIDOR AND EASTERN
RIDGES BY DAWN. MOSTLY AROUND AN ADDITIONAL INCH OF SNOWFALL WILL
BE POSSIBLE TONIGHT, WITH 1 TO 3 POSSIBLE IN LOCALIZED AREAS AND
THE EASTERN RIDGES. STRONG COLD AIR ADVECTION IN THE WAKE OF THE
FRONT WILL ALLOW FOR LOWS RANGING FROM THE TEENS ACROSS NORTH-
CENTRAL WV TO THE LOWER TEENS NORTH OF THE PITTSBURGH METRO.
TOTAL SNOWFALL FOR THIS AFTERNOON THROUGH TONIGHT WILL GENERALLY
BE 1 TO 2 INCHES ACROSS MUCH OF THE AREA. LOCALIZED AREAS OF UP
TO 3 INCHES WILL BE POSSIBLE NORTH OF THE PITTSBURGH METRO AND
ACROSS THE EASTERN RIDGES WITH COOLER TEMPS AT THE ONSET OF THE
SNOW. IN ADDITION, MOST LOWLAND AREAS SOUTH OF I-70 WILL SEE LESS
AN INCH. ALTHOUGH SNOW AMOUNTS FORECAST ARE MOSTLY SUB-ADVISORY
AMOUNTS, WILL CONTINUE THE WINTER WEATHER ADVISORY FOR AREAS NORTH
OF PITTSBURGH DUE TO TIMING OF THE SNOW IMPACTING THE EVENING
COMMUTE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
THERE IS OPERATIONAL MODEL AGREEMENT TO BEGIN THIS PERIOD THAT
HIGH PRESSURE WILL KEEP THE EARLY PORTION OF THE DAY DRY ACROSS
THE AREA. AFTER 18Z, AN INVERTED TROUGH OF LOW PRESSURE EXTENDING
FROM TEXAS INTO THE TENNESSEE VALLEY WILL SERVE TO DRAW MOISTURE
FROM THE GULF INTO THE AREA AS ANOTHER WAVE MOVES ACROSS THE
MIDWEST. THIS WILL CREATE A COMPLICATED MIXED PRECIPITATION
SCENARIO FOR THE UPPER OHIO VALLEY FOR FRIDAY NIGHT INTO EARLY
SATURDAY.
FORECAST CONSISTS OF A BLEND OF THE NAM/ECMWF/SREF WITH THE GFS
CONSIDERED A COLD OUTLIER. SURFACE LOW AND INVERTED TROUGH FROM
THE TN VALLEY WILL MERGE WITH NORTHERN STREAM WAVE AS IT SHIFTS INTO
THE MID-ATLANTIC FRIDAY NIGHT INTO SATURDAY MORNING. NAM/ECMWF
INDICATE THE 1000-850MB 1300M THICKNESS LINE STRADDLING NORTH-
CENTRAL WV AT THE ONSET FRIDAY NIGHT AND THEN SHIFTING NORTHWARD
TO THE PITTSBURGH METRO BY DAWN ON SATURDAY. THUS, FORECAST IS
FOR SNOW ACROSS THE AREA AT THE ONSET OF PRECIPITATION AFTER 00Z
SATURDAY, AND CHANGE TO FZRA AND TO RAIN OVERNIGHT SOUTH OF THE
MASON-DIXON LINE. NORTH OF THE MASON-DIXON LINE TO THE PITTSBURGH
METRO, FORECAST IS FOR AN EXTENDED PERIOD OF A WINTRY MIX WITH ICE
ACCUMULATIONS OF A TENTH TO TWO TENTHS OF AN INCH. NORTH OF THE
PITTSBURGH METRO, PRECIP WILL BE SNOW FOR THE MAJORITY, WITH 3 TO
6 INCHES POSSIBLE FOR THE I-80 CORRIDOR. WITH COLD AIR HANGING
ACROSS THE EASTERN RIDGES, A WINTER STORM WATCH HAS BEEN POSTED
FOR GARRETT COUNTY AND THE WESTMO/FAYETTE RIDGES FOR THE POTENTIAL
OF OVER A QUARTER INCH OF ICE. OTHERWISE, A TENTH TO TWO TENTHS OF
ICE ARE NOT OUT OF THE QUESTION FOR AREAS BETWEEN MASON-DIXON LINE
AND SOUTH OF THE I-80 CORRIDOR AND MAY LEAD TO AN ADVISORY.
SATURDAY...WINTRY MIX OF PRECIPITATION WILL COME TO AN END DURING
THE MORNING HOURS AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE
NORTHWEST.
FOR TEMPS, WITH COLD AIR BUILT IN BEHIND THE FRONT ON FRIDAY, TEMPS
WILL LIKELY REMAIN BELOW FREEZING THROUGHOUT THE DAY, WITH HIGHS
RANGING FROM THE LOWER 20S ACROSS THE I-80 CORRIDOR TO THE LOWER
30S ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV. WARM AIR
ADVECTION WILL TAKE PLACE SOUTH OF THE PITTSBURGH METRO FRIDAY
NIGHT, WITH TEMPS RISING INTO THE MID 30S BY DAWN. TEMPS WILL
REMAIN FAIRLY STEAD NORTH OF THE PITTSBURGH METRO IN THE MID TO
UPPER 20S. TEMPS WILL CONTINUE TO MODERATE ON SATURDAY, CONSISTING
OF A MAV/MET BLEND, RANGING FROM NEAR 30 ACROSS THE I-80 CORRIDOR
TO THE LOWER 40S ACROSS NORTH-CENTRAL WV.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
PER RECENT SREF MODEL OUTPUT, EXPECT DRY CONDITIONS FOR SATURDAY
NIGHT INTO SUNDAY EVENING. THEN BLEND OF RECENT SREF AND ECMWF MODEL
OUTPUT SHOW A COLD FRONT, COMING EAST FRONT THE ROCKIES, WILL BRING
SHOWERS LATE SUNDAY NIGHT INTO MONDAY NIGHT. THERE CAN BE A
SUFFICIENT COLD POOL IN THE WAKE OF THE FRONTAL PASSAGE TO CAUSE A
POSSIBLE CHANGE TO SNOW SHOWERS LATE MONDAY NIGHT AND TUESDAY.
WITH THE UPPER LEVEL JETSTREAM MAINTAINING A WAVY ZONAL PATTERN,
BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS A SECOND COLD
FRONT, COMING EAST FROM THE ROCKIES, CAN PROVIDE SHOWERS WEDNESDAY
NIGHT AND THURSDAY. THE PRECIPITATION TYPE THEN CAN BE RAIN OR SNOW
AS SURFACE TEMPERATURES WILL BE MAINLY IN THE 30S.
REGARDING OTHER ASPECTS OF THE TEMPERATURE FORECAST THIS PERIOD,
ZONAL JETSTREAM PATTERN SHOULD MAINTAIN VALUES GENERALLY WARMER THAN
NORMAL, WITH MONDAY AND THURSDAY HAVING VALUES MORE THAN 10 DEGREES
ABOVE NORMAL. TUESDAY SHOULD BE THE COLDEST DAY, BUT EVEN THEN
VALUES MAY BE NO COLDER THAN NORMAL.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
PER BLEND OF RECENT SURFACE AND RADAR DATA ALONG WITH NAM AND GFS
LAMP MODEL OUTPUT, EXPECT A PREFRONTAL SNOW BAND, WITH IFR
CONDITIONS, TO CONTINUE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY
THROUGH 04Z. PREFRONTAL SURFACE WINDS WILL BE FROM THE SOUTHWEST
WITH GUSTS TO 25 KTS. POSTFRONTAL WINDS WILL BE NORTHWEST AND
DECREASE TO 10 KTS BY LATE TONIGHT.
DURING LATE TONIGHT AND FRIDAY MORNING, EXPECT POST-SYSTEM COLD
POOL STRATOCUMULUS CEILINGS TO LIFT THROUGH MVFR LEVELS TO VFR
LEVELS BY MIDDAY.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
A WINTRY MIX WITH IFR RESTRICTIONS LATE FRIDAY NIGHT AND SATURDAY.
VFR SUNDAY. RAIN SHOWERS WITH POSSIBLE RESTRICTIONS MONDAY AND
MONDAY NIGHT, WITH A POSSIBLE CHANGE TO SNOW SHOWERS TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SATURDAY
MORNING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ007>009-013>016-022-023.
WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SATURDAY
MORNING FOR PAZ074-076.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
134 PM EST THU JAN 19 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF ACCUMULATING SNOW
THIS AFTERNOON INTO EARLY TONIGHT. LOW PRESSURE, MOVING NORTHEAST
FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, TO BRING A WINTRY
MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE POPS EARLY NORTH OF THE I-80 CORRIDOR AS SNOW MOVES IN
EARLY THIS AFTERNOON.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW AS A TROUGH MOVES ACROSS THE EASTERN GREAT LAKES.
AT THE SURFACE, A 999MB LOW IS LOCATED NORTH OF MICHIGAN. A COLD
FRONT EXTENDS SOUTH OF THIS FEATURE ACROSS MICHIGAN AND INTO
NORTHWEST OHIO. AHEAD OF THE FRONT, AN AREA OF LIGHT SNOW IS PUSHING
INTO EASTERN OHIO AND WESTERN PA. THE SNOW INCREASES IN INTENSITY
CLOSER TO THE FRONT, WITH MODERATE SNOW REPORTED A FEW OBS
UPSTREAM IN NORTHWEST OHIO.
THIS AFTERNOON...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST
TOWARD THE AREA, WITH THE RUC/HRRR WIND SHIFT SUPPORTING THE FRONT
REACHING A ZANESVILLE-NEW PHILADELPHIA-FRANKLIN LINE BY 00Z THIS
EVENING. FORECAST CONSISTS OF A BLEND OF THE HRRR/NAM4KM, WITH
LIGHT SNOW REACHING AREAS THE PITTSBURGH METRO AFTER 19Z WITH LIKELY
POPS REACHING THE EASTERN RIDGES OF MD/WV BY 23Z. SNOW WILL
INCREASE IN INTENSITY AT TIMES, REDUCING VISIBILITIES THIS
EVENING. A FACTOR IN THE SNOWFALL ACCUMULATION AT LEAST INITIALLY
WILL BE SURFACE TEMPS, WITH AREAS SOUTH OF I-70 WARMING INTO THE
MID TO UPPER 30S. THIS WILL LIMIT SNOWFALL ACCUMULATION THERE
INITIALLY. THUS FORECAST INTO THE EARLY EVENING IS FOR AROUND AN
INCH NORTH OF I-70 AND FOR A HALF OF AN INCH OR LESS SOUTHWARD.
FOR TEMPS, FORECAST IS A FEW DEGREES WARMER THAN A LAMP/HRRR
BLEND, WITH HIGHS RANGING FROM THE UPPER 30S ACROSS NORTH-CENTRAL
WV TO NEAR 30 ALONG THE I-80 CORRIDOR.
TONIGHT...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST ACROSS THE
UPPER OHIO VALLEY, PUSHING SOUTHEAST OF THE RIDGES BY 03Z FRI.
THE BEST CHANCE FOR SNOW ACCUMULATION AND POTENTIALLY HAZARDOUS
TRAVEL WILL BE AROUND SUNSET THROUGH MIDNIGHT AS SNOW PUSHES ACROSS THE
AREA. SNOW WILL BEGIN TO TAPER OFF BEHIND THE FRONT WITH JUST A
FEW LINGERING SNOW SHOWERS ALONG THE I-80 CORRIDOR AND EASTERN
RIDGES BY DAWN. MOSTLY AROUND AN ADDITIONAL INCH OF SNOWFALL WILL
BE POSSIBLE TONIGHT, WITH 1 TO 3 POSSIBLE IN LOCALIZED AREAS AND
THE EASTERN RIDGES. STRONG COLD AIR ADVECTION IN THE WAKE OF THE
FRONT WILL ALLOW FOR LOWS RANGING FROM NEAR 20 ACROSS NORTH-
CENTRAL WV TO THE MID TO UPPER TEENS ELSEWHERE.
TOTAL SNOWFALL FOR THIS AFTERNOON THROUGH TONIGHT WILL GENERALLY
BE 1 TO 2 INCHES ACROSS MUCH OF THE AREA. LOCALIZED AREAS OF UP
TO 3 INCHES WILL BE POSSIBLE NORTH OF THE PITTSBURGH METRO AND
ACROSS THE EASTERN RIDGES WITH COOLER TEMPS AT THE ONSET OF THE
SNOW. IN ADDITION, MOST LOWLAND AREAS SOUTH OF I-70 WILL SEE LESS
AN INCH. ALTHOUGH SNOW AMOUNTS FORECAST ARE MOSTLY SUB-ADVISORY
AMOUNTS, WILL CONTINUE THE WINTER WEATHER ADVISORY FOR AREAS NORTH
OF PITTSBURGH DUE TO TIMING OF THE SNOW IMPACTING THE EVENING
COMMUTE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
MUCH OF FRIDAY LOOKS TO BE DRY...BUT NEXT SHORTWAVE IN PROGRESSIVE
FLOW IS TIMED TO GENERATE MORE PRECIP BY LATE DAY. LATEST
DETERMINISTIC MODELS DIFFER GREATLY IN TIMING...TEMPERATURE
PROFILES...AND THE RESULTING PRECIP TYPES AND AMOUNTS. FORECAST
IS THUS BASED ON A COMBO OF PERSISTENCE AND NAM/GFS BLEND AND
FEATURES A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY. BEST CHANCE
OF ACCUMULATING SNOW APPEARS FOR NOW TO BE OVER AREAS NORTH OF
PITTSBURGH...BUT ICE ACCUMULATION MAY BE A DEVELOPING HAZARD FOR
THE REMAINDER OF THE AREA. WILL ISSUE A HAZARDOUS WEATHER OUTLOOK
FOR THESE POTENTIALS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
PER BLEND OF RECENT SURFACE AND RADAR DATA ALONG WITH NAM AND GFS
LAMP MODEL OUTPUT, EXPECT A PREFRONTAL SNOW BAND, WITH IFR CONDITIONS, TO
MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 04Z.
PREFRONTAL SURFACE WINDS WILL BE FROM THE SOUTHWEST WITH GUSTS TO
25 KTS. POSTFRONTAL WINDS WILL BE NORTHWEST AND DECREASE TO 10 KTS
BY LATE TONIGHT.
DURING LATE TONIGHT AND FRIDAY MORNING, EXPECT POST-SYSTEM COLD
POOL STRATOCUMULUS CEILINGS TO LIFT THROUGH MVFR LEVELS TO VFR
LEVELS BY MIDDAY.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
A WINTRY MIX WITH RESTRICTIONS LATE FRIDAY NIGHT AND SATURDAY.
VFR SUNDAY. RAIN SHOWERS WITH RESTRICTIONS MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ007>009-013>016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1250 PM EST THU JAN 19 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF ACCUMULATING SNOW
THIS AFTERNOON INTO EARLY TONIGHT. LOW PRESSURE, MOVING NORTHEAST
FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, TO BRING A WINTRY
MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATE MORNING ENHANCED SHORT TERM FORECAST UPDATE HAD BEEN ISSUED
TO SLOW THE ONSET OF SNOW BY A FEW HOURS THIS AFTERNOON.
OTHERWISE, LITTLE CHANGE TO THE GOING FORECAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW AS A TROUGH MOVES ACROSS THE GREAT LAKES. AT THE
SURFACE, A 1000MB LOW IS LOCATED NORTH OF MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST OF THIS FEATURE ACROSS MICHIGAN AND INTO
INDIANA. AHEAD OF THE FRONT, AN AREA OF LIGHT SNOW IS PUSHING INTO THE
NORTHWEST HALF OF OHIO. THE SNOW INCREASES IN INTENSITY CLOSER TO
THE FRONT, WITH MODERATE SNOW REPORTED WITH SEVERAL OBS UPSTREAM
IN INDIANA.
THIS AFTERNOON...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST
TOWARD THE AREA, WITH THE RUC/HRRR WIND SHIFT SUPPORTING THE FRONT
REACHING A ZANESVILLE-NEW PHILADELPHIA-FRANKLIN LINE BY 00Z THIS
EVENING. FORECAST CONSISTS OF A BLEND OF THE HRRR/NAM4KM, WITH
LIGHT SNOW REACHING AREAS NORTH AND WEST OF PITTSBURGH BY 19Z WITH
LIKELY POPS REACHING THE EASTERN RIDGES OF MD/WV BY 23Z. SNOW WILL
INCREASE IN INTENSITY AT TIMES, REDUCING VISIBILITIES THIS
EVENING. A FACTOR IN THE SNOWFALL ACCUMULATION AT LEAST INITIALLY
WILL BE SURFACE TEMPS, WITH AREAS SOUTH OF I-70 WARMING INTO THE
MID TO UPPER 30S. THIS WILL LIMIT SNOWFALL ACCUMULATION THERE
INITIALLY. THUS FORECAST INTO THE EARLY EVENING IS FOR AROUND AN
INCH NORTH OF I-70 AND FOR A HALF OF AN INCH OR LESS SOUTHWARD.
FOR TEMPS, FORECAST IS A FEW DEGREES WARMER THAN A LAMP/HRRR BLEND,
WITH HIGHS RANGING FROM THE UPPER 30S ACROSS NORTH-CENTRAL WV TO
NEAR 30 ALONG THE I-80 CORRIDOR.
TONIGHT...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST ACROSS THE
UPPER OHIO VALLEY, PUSHING SOUTHEAST OF THE RIDGES BY 03Z FRI.
THE BEST CHANCE FOR SNOW ACCUMULATION AND POTENTIALLY HAZARDOUS
TRAVEL WILL BE AFTER SUNSET THROUGH MIDNIGHT AS SNOW PUSHES ACROSS
THE AREA. SNOW WILL BEGIN TO TAPER OFF BEHIND THE FRONT WITH JUST
A FEW LINGERING SNOW SHOWERS ALONG THE I-80 CORRIDOR AND EASTERN
RIDGES BY DAWN. MOSTLY AROUND AN ADDITIONAL INCH OF SNOWFALL WILL BE
POSSIBLE TONIGHT, WITH 1 TO 3 POSSIBLE IN LOCALIZED AREAS AND THE
EASTERN RIDGES. STRONG COLD AIR ADVECTION IN THE WAKE OF THE FRONT
WILL ALLOW FOR LOWS RANGING FROM NEAR 20 ACROSS NORTH-CENTRAL WV TO
THE MID TO UPPER TEENS ELSEWHERE.
TOTAL SNOWFALL FOR THIS AFTERNOON THROUGH TONIGHT WILL GENERALLY
BE 1 TO 2 INCHES ACROSS MUCH OF THE AREA. LOCALIZED AREAS OF UP
TO 3 INCHES WILL BE POSSIBLE NORTH OF THE PITTSBURGH METRO AND
ACROSS THE EASTERN RIDGES WITH COOLER TEMPS AT THE ONSET OF THE
SNOW. IN ADDITION, AREAS SOUTH OF I-70 WILL SEE AROUND AN INCH.
ALTHOUGH SNOW AMOUNTS FORECAST ARE MOSTLY SUB-ADVISORY AMOUNTS,
WILL CONTINUE THE WINTER WEATHER ADVISORY FOR AREAS NORTH OF
PITTSBURGH DUE TO TIMING OF THE SNOW IMPACTING THE EVENING
COMMUTE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
MUCH OF FRIDAY LOOKS TO BE DRY...BUT NEXT SHORTWAVE IN PROGRESSIVE
FLOW IS TIMED TO GENERATE MORE PRECIP BY LATE DAY. LATEST
DETERMINISTIC MODELS DIFFER GREATLY IN TIMING...TEMPERATURE
PROFILES...AND THE RESULTING PRECIP TYPES AND AMOUNTS. FORECAST
IS THUS BASED ON A COMBO OF PERSISTENCE AND NAM/GFS BLEND AND
FEATURES A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY. BEST CHANCE
OF ACCUMULATING SNOW APPEARS FOR NOW TO BE OVER AREAS NORTH OF
PITTSBURGH...BUT ICE ACCUMULATION MAY BE A DEVELOPING HAZARD FOR
THE REMAINDER OF THE AREA. WILL ISSUE A HAZARDOUS WEATHER OUTLOOK
FOR THESE POTENTIALS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
PER BLEND OF RECENT SURFACE AND RADAR DATA ALONG WITH NAM AND GFS
LAMP MODEL OUTPUT, EXPECT A PREFRONTAL SNOW BAND, WITH IFR CONDITIONS, TO
MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 04Z.
PREFRONTAL SURFACE WINDS WILL BE FROM THE SOUTHWEST WITH GUSTS TO
25 KTS. POSTFRONTAL WINDS WILL BE NORTHWEST AND DECREASE TO 10 KTS
BY LATE TONIGHT.
DURING LATE TONIGHT AND FRIDAY MORNING, EXPECT POST-SYSTEM COLD
POOL STRATOCUMULUS CEILINGS TO LIFT THROUGH MVFR LEVELS TO VFR
LEVELS BY MIDDAY.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
A WINTRY MIX WITH RESTRICTIONS LATE FRIDAY NIGHT AND SATURDAY.
VFR SUNDAY. RAIN SHOWERS WITH RESTRICTIONS MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ007>009-013>016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1139 AM EST THU JAN 19 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF ACCUMULATING SNOW
THIS AFTERNOON INTO EARLY TONIGHT. LOW PRESSURE, MOVING NORTHEAST
FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, TO BRING A WINTRY
MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATE MORNING ENHANCED SHORT TERM FORECAST UPDATE HAD BEEN ISSUED
TO SLOW THE ONSET OF SNOW BY A FEW HOURS THIS AFTERNOON.
OTHERWISE, LITTLE CHANGE TO THE GOING FORECAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW AS A TROUGH MOVES ACROSS THE GREAT LAKES. AT THE
SURFACE, A 1000MB LOW IS LOCATED NORTH OF MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST OF THIS FEATURE ACROSS MICHIGAN AND INTO
INDIANA. AHEAD OF THE FRONT, AN AREA OF LIGHT SNOW IS PUSHING INTO THE
NORTHWEST HALF OF OHIO. THE SNOW INCREASES IN INTENSITY CLOSER TO
THE FRONT, WITH MODERATE SNOW REPORTED WITH SEVERAL OBS UPSTREAM
IN INDIANA.
THIS AFTERNOON...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST
TOWARD THE AREA, WITH THE RUC/HRRR WIND SHIFT SUPPORTING THE FRONT
REACHING A ZANESVILLE-NEW PHILADELPHIA-FRANKLIN LINE BY 00Z THIS
EVENING. FORECAST CONSISTS OF A BLEND OF THE HRRR/NAM4KM, WITH
LIGHT SNOW REACHING AREAS NORTH AND WEST OF PITTSBURGH BY 19Z WITH
LIKELY POPS REACHING THE EASTERN RIDGES OF MD/WV BY 23Z. SNOW WILL
INCREASE IN INTENSITY AT TIMES, REDUCING VISIBILITIES THIS
EVENING. A FACTOR IN THE SNOWFALL ACCUMULATION AT LEAST INITIALLY
WILL BE SURFACE TEMPS, WITH AREAS SOUTH OF I-70 WARMING INTO THE
MID TO UPPER 30S. THIS WILL LIMIT SNOWFALL ACCUMULATION THERE
INITIALLY. THUS FORECAST INTO THE EARLY EVENING IS FOR AROUND AN
INCH NORTH OF I-70 AND FOR A HALF OF AN INCH OR LESS SOUTHWARD.
FOR TEMPS, FORECAST IS A FEW DEGREES WARMER THAN A LAMP/HRRR BLEND,
WITH HIGHS RANGING FROM THE UPPER 30S ACROSS NORTH-CENTRAL WV TO
NEAR 30 ALONG THE I-80 CORRIDOR.
TONIGHT...THE COLD FRONT WILL QUICKLY SLIDE SOUTHEAST ACROSS THE
UPPER OHIO VALLEY, PUSHING SOUTHEAST OF THE RIDGES BY 03Z FRI.
THE BEST CHANCE FOR SNOW ACCUMULATION AND POTENTIALLY HAZARDOUS
TRAVEL WILL BE AFTER SUNSET THROUGH MIDNIGHT AS SNOW PUSHES ACROSS
THE AREA. SNOW WILL BEGIN TO TAPER OFF BEHIND THE FRONT WITH JUST
A FEW LINGERING SNOW SHOWERS ALONG THE I-80 CORRIDOR AND EASTERN
RIDGES BY DAWN. MOSTLY AROUND AN ADDITIONAL INCH OF SNOWFALL WILL BE
POSSIBLE TONIGHT, WITH 1 TO 3 POSSIBLE IN LOCALIZED AREAS AND THE
EASTERN RIDGES. STRONG COLD AIR ADVECTION IN THE WAKE OF THE FRONT
WILL ALLOW FOR LOWS RANGING FROM NEAR 20 ACROSS NORTH-CENTRAL WV TO
THE MID TO UPPER TEENS ELSEWHERE.
TOTAL SNOWFALL FOR THIS AFTERNOON THROUGH TONIGHT WILL GENERALLY
BE 1 TO 2 INCHES ACROSS MUCH OF THE AREA. LOCALIZED AREAS OF UP
TO 3 INCHES WILL BE POSSIBLE NORTH OF THE PITTSBURGH METRO AND
ACROSS THE EASTERN RIDGES WITH COOLER TEMPS AT THE ONSET OF THE
SNOW. IN ADDITION, AREAS SOUTH OF I-70 WILL SEE AROUND AN INCH.
ALTHOUGH SNOW AMOUNTS FORECAST ARE MOSTLY SUB-ADVISORY AMOUNTS,
WILL CONTINUE THE WINTER WEATHER ADVISORY FOR AREAS NORTH OF
PITTSBURGH DUE TO TIMING OF THE SNOW IMPACTING THE EVENING
COMMUTE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
MUCH OF FRIDAY LOOKS TO BE DRY...BUT NEXT SHORTWAVE IN PROGRESSIVE
FLOW IS TIMED TO GENERATE MORE PRECIP BY LATE DAY. LATEST
DETERMINISTIC MODELS DIFFER GREATLY IN TIMING...TEMPERATURE
PROFILES...AND THE RESULTING PRECIP TYPES AND AMOUNTS. FORECAST
IS THUS BASED ON A COMBO OF PERSISTENCE AND NAM/GFS BLEND AND
FEATURES A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY. BEST CHANCE
OF ACCUMULATING SNOW APPEARS FOR NOW TO BE OVER AREAS NORTH OF
PITTSBURGH...BUT ICE ACCUMULATION MAY BE A DEVELOPING HAZARD FOR
THE REMAINDER OF THE AREA. WILL ISSUE A HAZARDOUS WEATHER OUTLOOK
FOR THESE POTENTIALS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
VFR FORECAST INTO THE AFTERNOON. AFTER DAWN, THERE WILL BE IN AN
INCREASE IN MID DECK CLOUD COVER AS WELL AS STRENGTHENING SW SFC
WINDS, WITH SOME GUSTS TO 20 KTS BY MIDDAY.
COLD FRONT WILL REACH THE WESTERN EDGE OF THE AREA AROUND 20Z. MVFR
TO IFR RESTRICTIONS WITH SNOW AND LOW CLOUDS EXPECTED AT ALL
PORTS DURING THE AFTERNOON AND EVENING HOURS.
OUTLOOK...TONIGHT NIGHT THROUGH MONDAY...
RESTRICTIONS WITH SNOW AND LOW CLOUDS WILL CONTINUE THROUGH THIS
EVENING. VIS SHOULD QUICKLY IMPROVE AFTER 06Z AS AREA OF SNOW
SHOWERS MOVES SOUTHEAST.
VFR CONDITIONS WILL BRIEFLY RETURN FRIDAY AS A SURFACE HIGH SLIDES
ACROSS THE REGION. A SYSTEM TRACKING SOUTH OF THE AREA WILL BRING A
WINTRY MIX WITH RESTRICTIONS FRIDAY NIGHT AND SATURDAY. AFTER A
PERIOD OF VFR WEATHER SUNDAY, AN APPROACHING FRONT IS PROGGED TO
SPREAD SCATTERED RAIN SHOWERS AND RESTRICTIONS ACROSS THE TERMINALS
MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ007>009-013>016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
819 AM EST THU JAN 19 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF ACCUMULATING SNOW
THIS AFTERNOON INTO EARLY TONIGHT. LOW PRESSURE, COMING NORTHEAST
FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, TO BRING A WINTRY
MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT HRRR MODEL OUTPUT CONTINUES TO SHOW FRONTAL BAND OF SNOW
WILL BEGIN SPREADING SOUTHEASTWARD ACROSS THE UPPER OHIO VALLEY
DURING MIDDAY. TEMPERATURES NORTH WILL LIKELY NOT GET WARMER THAN
FREEZING BEFOREHAND, WHILE TEMPERATURES SOUTH WILL. ONCE PRECIPITATION
BEGINS, ALL TEMPERATURES WILL DROP TO BELOW FREEZING, HENCE THIS
SHOULD BE AN ALL SNOW EVENT.
CONTINUE TO EXPECT SNOW AMOUNTS FOR MOST PLACES TO BE AROUND 2
INCHES, POSSIBLY MORE NORTH. WILL MAINTAIN CURRENT WINTER WEATHER
ADVISORIES NORTH, AND MAY CONSIDER EXPANSION SOUTH, DUE TO POTENTIAL
OF HAZARDOUS IMPACTS WITH TEMPERATURES NEAR FREEZING AND SNOWFALL
CONTINUING PAST THE EVENING COMMUTER RUSH.
HIGH PRESSURE WILL BUILD IN THE WAKE OF THE FRONT TONIGHT AND
GRADUALLY END THE SNOW. TEMPERATURES WERE FORECAST A FEW DEGREES
UNDER THE SEASONAL AVERAGES USING TWEAKED NAMDNG5 NMBRS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
MUCH OF FRIDAY LOOKS TO BE DRY...BUT NEXT SHORTWAVE IN PROGRESSIVE
FLOW IS TIMED TO GENERATE MORE PRECIP BY LATE DAY. LATEST
DETERMINISTIC MODELS DIFFER GREATLY IN TIMING...TEMPERATURE
PROFILES...AND THE RESULTING PRECIP TYPES AND AMOUNTS. FORECAST
IS THUS BASED ON A COMBO OF PERSISTENCE AND NAM/GFS BLEND AND
FEATURES A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY. BEST CHANCE
OF ACCUMULATING SNOW APPEARS FOR NOW TO BE OVER AREAS NORTH OF
PITTSBURGH...BUT ICE ACCUMULATION MAY BE A DEVELOPING HAZARD FOR
THE REMAINDER OF THE AREA. WILL ISSUE A HAZARDOUS WEATHER OUTLOOK
FOR THESE POTENTIALS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
VFR FORECAST INTO THE AFTERNOON. AFTER DAWN, THERE WILL BE IN AN
INCREASE IN MID DECK CLOUD COVER AS WELL AS STRENGTHENING SW SFC
WINDS, WITH SOME GUSTS TO 20 KTS BY MIDDAY.
COLD FRONT WILL REACH THE WESTERN EDGE OF THE AREA AROUND 20Z. MVFR
TO IFR RESTRICTIONS WITH SNOW AND LOW CLOUDS EXPECTED AT ALL
PORTS DURING THE AFTERNOON AND EVENING HOURS.
OUTLOOK...TONIGHT NIGHT THROUGH MONDAY...
RESTRICTIONS WITH SNOW AND LOW CLOUDS WILL CONTINUE THROUGH THIS
EVENING. VIS SHOULD QUICKLY IMPROVE AFTER 06Z AS AREA OF SNOW
SHOWERS MOVES SOUTHEAST.
VFR CONDITIONS WILL BRIEFLY RETURN FRIDAY AS A SURFACE HIGH SLIDES
ACROSS THE REGION. A SYSTEM TRACKING SOUTH OF THE AREA WILL BRING A
WINTRY MIX WITH RESTRICTIONS FRIDAY NIGHT AND SATURDAY. AFTER A
PERIOD OF VFR WEATHER SUNDAY, AN APPROACHING FRONT IS PROGGED TO
SPREAD SCATTERED RAIN SHOWERS AND RESTRICTIONS ACROSS THE TERMINALS
MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR PAZ007>009-013>016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
808 AM EST THU JAN 19 2012
.SYNOPSIS...
ACCUMULATING SNOW SHOWERS CAN BE EXPECTED TODAY AS A FAST MOVING
COLD FRONT CROSSES THE UPPER OHIO VALLEY REGION. LOW PRESSURE,
COMING NORTHEAST FROM TEXAS, WILL CROSS JUST SOUTH OF THE AREA, TO BRING
A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT HRRR MODEL OUTPUT CONTINUES TO SHOW FRONTAL BAND OF SNOW
SHOWERS WILL BEGIN SPREADING SOUTHEASTWARD ACROSS THE UPPER OHIO
VALLEY DURING MIDDAY. TEMPERATURES NORTH WILL LIKELY NOT GET
WARMER THAN FREEZING, WHILE TEMPERATURES SOUTH WILL. ONCE
PRECIPITATION BEGINS, ALL TEMPERATURES WILL DROP TO BELOW
FREEZING, HENCE THIS SHOULD BE AN ALL SNOW EVENT.
CONTINUE TO EXPECT SNOW AMOUNTS FOR MOST PLACES TO BE AROUND 2
INCHES, POSSIBLY MORE NORTH. WILL MAINTAIN CURRENT WINTER WEATHER
ADVISORIES NORTH, AND MAY CONSIDER EXPANSION SOUTH, CONTINUING POTENTIAL
OF HAZARDOUS IMPACTS WITH TEMPERATURES NEAR FREEZING AND SNOWFALL
CONTINUING PAST THE EVENING COMMUTER RUSH.
HIGH PRESSURE WILL BUILD IN THE WAKE OF THE FRONT TONIGHT AND
GRADUALLY END THE SNOW. TEMPERATURES WERE FORECAST A FEW DEGREES
UNDER THE SEASONAL AVERAGES USING TWEAKED NAMDNG5 NMBRS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
MUCH OF FRIDAY LOOKS TO BE DRY...BUT NEXT SHORTWAVE IN PROGRESSIVE
FLOW IS TIMED TO GENERATE MORE PRECIP BY LATE DAY. LATEST
DETERMINISTIC MODELS DIFFER GREATLY IN TIMING...TEMPERATURE
PROFILES...AND THE RESULTING PRECIP TYPES AND AMOUNTS. FORECAST
IS THUS BASED ON A COMBO OF PERSISTENCE AND NAM/GFS BLEND AND
FEATURES A WINTRY MIX FOR FRIDAY NIGHT AND SATURDAY. BEST CHANCE
OF ACCUMULATING SNOW APPEARS FOR NOW TO BE OVER AREAS NORTH OF
PITTSBURGH...BUT ICE ACCUMULATION MAY BE A DEVELOPING HAZARD FOR
THE REMAINDER OF THE AREA. WILL ISSUE A HAZARDOUS WEATHER OUTLOOK
FOR THESE POTENTIALS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
VFR FORECAST INTO THE AFTERNOON. AFTER DAWN, THERE WILL BE IN AN
INCREASE IN MID DECK CLOUD COVER AS WELL AS STRENGTHENING SW SFC
WINDS, WITH SOME GUSTS TO 20 KTS BY MIDDAY.
COLD FRONT WILL REACH THE WESTERN EDGE OF THE AREA AROUND 20Z. MVFR
TO IFR RESTRICTIONS WITH SNOW SHOWERS AND LOW CLOUDS EXPECTED AT ALL
PORTS DURING THE AFTERNOON AND EVENING HOURS.
OUTLOOK...TONIGHT NIGHT THROUGH MONDAY...
RESTRICTIONS WITH SNOW AND LOW CLOUDS WILL CONTINUE THROUGH THIS
EVENING. VIS SHOULD QUICKLY IMPROVE AFTER 06Z AS AREA OF SNOW
SHOWERS MOVES SOUTHEAST.
VFR CONDITIONS WILL BRIEFLY RETURN FRIDAY AS A SURFACE HIGH SLIDES
ACROSS THE REGION. A SYSTEM TRACKING SOUTH OF THE AREA WILL BRING A
WINTRY MIX WITH RESTRICTIONS FRIDAY NIGHT AND SATURDAY. AFTER A
PERIOD OF VFR WEATHER SUNDAY, AN APPROACHING FRONT IS PROGGED TO
SPREAD SCATTERED RAIN SHOWERS AND RESTRICTIONS ACROSS THE TERMINALS
MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR PAZ007>009-013>016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1226 AM EST THU JAN 19 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WEAK SHRTWV RDGING
IMPACTING THE UPR GRT LKS WITHIN LO AMPLITUDE TROFFING OVER CENTRAL
NAMERICA TO THE S OF CLOSED LO OVER HUDSON BAY. AS OF EARLY THIS
AFTN...THE SUBSIDENCE ASSOCIATED WITH THE SHRTWV RDG HAS ENDED PCPN
EVERYWHERE EXCEPT OVER THE N HALF OF THE KEWEENAW PENINSULA...WHERE
A LO PRES TROF LINGERS TO THE N OF SFC HI PRES IN THE OH RIVER
VALLEY. BUT AS THE FLOW CONTINUES TO BACK TO THE SW BTWN THE
DEPARTING HI TO THE SE AND ANOTHER SHRTWV MOVING E THRU THE NRN
PLAINS...THESE SHSN ARE TENDING TO DRIFT NEWD INTO LK SUP. THE
DISTURBANCE TO THE W IS A POTENT ONE WITH SUPPORTING H5/H3 JET MAX
AND WIND SPEEDS OF 100KT/150KT DIGGING ESEWD THRU THE NW PLAINS.
HOWEVER...SINCE UPSTREAM AIRMASS IS FAIRLY DRY...THE BULK OF THE
PCPN IS FALLING TO THE N OF WARM FNT AND ON THE COLD SIDE OF COLD
FNT ATTENDANT TO SFC LO IN WCNTRL MN. GUSTY NW WINDS UP TO 35-40KTS
ARE DRIVING VERY COLD AIR SEWD INTO THE NRN PLAINS BEHIND THIS LO
AND AHEAD OF VIGOROUS PRES RISE CENTER IN THE DAKOTAS. THE 12Z H85
TEMP AT GREAT FALLS MT WAS -31C.
&&
.SHORT TERM DISCUSSION /TNGT AND THU/...
TNGT...SHRTWV TO THE W IS FCST TO SLIDE ESEWD THRU NRN WI AND INTO
NRN LWR MI BY 12Z THU WHILE SFC LO CENTER SHIFTS ENEWD ACRS THE
KEWEENAW AND INTO ERN LK SUP BY 12Z THU. STRONG SLY FLOW OF H85
TEMPS ARND -12C OFF THE 4C WARM WATERS OF LK MI AHEAD OF THIS
FEATURE INDICATE THERE WL BE ENUF INSTABILITY TO GENERATE LES...
WITH SOME ENHANCEMENT AS DEEP LYR QVECTOR CNVGC/MSTR ASSOCIATED WITH
APRCHG SHRTWV ARRIVE OVHD. 12Z NAM/CNDN MODELS SHOW QPF OF 0.20-0.30
INCH NEAR ERY. CONSIDERING FVRBL OMEGA PROFILE WITHIN DGZ...EXPECT
HI SN/WATER RATIO ARND 25:1 AND UP TO 6 INCHES OF SN E OF ERY. THE
WINDOW OF OPPORTUNITY WL BE RATHER NARROW AS THE FLOW IS PROGGED TO
VEER MORE TO THE WSW OVERNGT...SHIFTING THE HEAVIER SHSN TO THE E.
ISSUED LES ADVY EARLIER TDAY FOR THIS EXPECTED SN. FARTHER
W...FAIRLY DRY ENVIRONMENT AHEAD OF THE COLD FNT AS OBSVD THIS AFTN
SUG THERE WL BE LTL IN THE WAY OF SN UNTIL THE COLD FROPA...ABOUT
03Z OVER THE FAR W AT IWD TO ARND 12Z AT ERY. WITH SHARP THERMAL
GRADIENT/FGEN...SUSPECT THERE WL BE A PERIOD OF SN WITH THE
FROPA...ESPECIALLY NEAR LK SUP WHERE THERE WL BE EXTRA
MOISTENING/UPSLOPE FLOW. OVER THE SCNTRL... EXPECT ONLY SCT -SHSN
WITH MORE DOWNSLOPE FLOW. ALTHOUGH THE SYNOPTIC SN WL CUT OFF
QUICKLY WITH FAST ARRIVAL OF DEEP LYR QVECTOR DVGC/SUBSIDENCE...LES
WL DVLP IN THE STRENGTHENING NW FLOW OF ARCTIC AIR LEFT IN THE WAKE
OF DEPARTING LO. H85 TEMPS ARE PROGGED TO PLUMMET TO ARND -25C AT
IWD BY 12Z THU. ANOTHER SGNFT FEATURE TNGT WL BE STRENGTHENING NW
FLOW ASSOCIATED WITH STRONG CAD/IN ADVANCE OF APRCHG PRES RISE
CENTER THAT IS FCST TO REACH THE W TOWARD 12Z. PREFER THE STRONGER
H925 WINDS UP TO 40-45KTS SHOWN BY THE 12Z GFS/LOCAL WRF-ARW RUNS
GIVEN THE STRENGTH OF THIS DISTURBANCE...AND THESE WINDS WL MIX
EFFICIENTLY TO THE SFC WITH VIGOROUS CAD. THE COMBINATION OF THE
STRONG WINDS AND FALLING TEMPS WL PUSH WIND CHILLS AS LO AS -20 TO
-25F OVER GOGEBIC COUNTY.
THU...GUSTY NW WINDS/VIGOROUS CAD WITH H85 TEMPS FALLING TO ARND
-25C AND STRONG SUBSIDENCE/DEEP LYR QVECTOR DVGC WL BE IN PLACE
BEHIND THE DEPARTING SFC LO/UPR DISTURBANCE AT DAYBREAK. EXPECT THE
WINDS TO DIMINISH THU AFTN FOLLOWING PASSAGE OF PRES RISE CENTER TO
THE E AFT 18Z. WITH THE SLOW APRCH OF HI PRES FM THE W...MODEL FCST
SDNGS SHOW THE INVRN BASE AT IWD SINKING TO AOB 3K FT AGL BY LATE IN
THE DAY AS WINDS BACK MORE TO THE W...DIMINISHING THE PCPN IN THAT
AREA. THIS FLOW WL REMAIN FAVORABLE FOR AREAS FARTHER TO THE N THRU
THE KEWEENAW...MAINTAINING HIER INVRN HGTS. EXPECT LES TO INTENSIFY
OVER THE E WITH ENHANCED LLVL CNVGC PERSISTING AT THE END OF LONG NW
FETCH OVER THE OPEN WATERS OF LK SUP. WITH INVRN BASE FCST ARND 5K
FT AGL OVER THE KEWEENAW AND OVER THE E...LES CHART SUGS UP TO 6
INCHES OF SN PER 12 HR PERIOD. ALTHOUGH THESE AMOUNTS MAY NOT EASILY
EXCEED WARNING THRESHOLDS...THE ARRIVAL OF MUCH COLDER AIR THAT
DROPS H85 TEMPS TO ARND -25C AND THE DGZ ALMOST TO THE SFC OVER THE
W AS WELL AS THE GUSTY WINDS WL HAMPER SN GROWTH...LEADING TO
SMALLER SN FLAKES. WITH GUSTY WINDS...EXPECT EFFICIENT REDUCTION IN
VSBY THAT JUSTIFIES GOING WITH WRNGS IN MOST COUNTIES EXCEPT FOR
GOGEBIC COUNTY...WHICH WL NOT BE AS EXPOSED TO THE STRONG WINDS.
WITH THE INFLUX OF COLD AIR...TEMPS WL BE STEADY OR SLOWLY FALLING
THRU THE DAY.
.LONG TERM /00Z FRI THROUGH NEXT WED/...
THURSDAY NIGHT INTO FRI...NW LES WILL BE ONGOING AT THE START OF THE
PERIOD...BUT INTENSITY SHOULD BE LIGHTER THAN THU MORNING AS DRY AIR
AND SUBSIDENCE ALOFT LOWERS INVERSION HEIGHTS TOWARDS 4-5KFT.
A SECONDARY SURGE OF LLVL MOISTURE WILL ARRIVE TOWARDS MIDNIGHT AS
MID LVL RIDGING SLIDES TO THE E OF THE AREA. THIS ADDITIONAL
MOISTURE BOOSTS THE INVERSION HEIGHTS TO 5-6KFT BY 06Z. AS THE HIGH
MOVES FARTHER SE AND A WEAK TROUGH SLIDES OVER NRN LAKE
SUPERIOR...LOW LEVEL FLOW WILL BECOME MORE FROM THE WSW. 850MB TEMPS
WILL WARM SOME TO AROUND -22C...WHICH PLACES MORE OF THE DGZ IN THE
BEST LIFT. THIS IS ALSO NOTED BY THE LAKE EFFECT SNOW PARAMETER
INCREASING TO AROUND 0.75 OVER THE KEWEENAW BY 03Z FRI. THE BACKING
WINDS WILL TEND TO FAVOR A STRONGER LES BAND FOCUSING SOMEWHERE OVER
NWRN UPPER MI FROM NEAR ONTONAGON INTO THE KEWEENAW...AND SHOULD
MOVE N THROUGH THE DAY AS WINDS BECOME MORE SWLY. LIKELY POPS FROM
THE PREVIOUS FORECAST LOOK GOOD...SO WILL MAKE MINOR TREAKS TO THOSE
GRIDS. ONGOING MULTI BANDED LES OVER ERN UPPER MI WILL MOVE OFFSHORE
BY 18Z FRI AS WINDS BECOME SWLY...BUT THERE MAY BE A PERIOD OF
STRONGER SNOW DUE TO CONVERGENCE AS WINDS BACK...BUT THAT MAY STAY
JUST OFFSHORE AS WELL.
WENT WITH THE LOW END OF GUIDANCE FOR TEMPS THU NIGHT. COLD...DRY
AIR AND DECREASING WINDS WILL BRING LOW TEMPS DOWN TO NEAR -20 OVER
THE INTERIOR WEST. WINDS WILL BE LIGHT AT AROUND 5KTS...BUT WIND
CHILLS WILL STILL FALL TO AROUND -30. CONTINUED TO HIGHLIGHT THIS
THREAT IN THE HWO. HIGHS WILL BE IN THE TEENS FRI.
AN UPPER SHORTWAVE MOVES TO OUR S FRI AFTERNOON...LEADING TO SOME
PRECIP SKIRTING THE SRN CWA. AT THIS TIME...THE MENOMINEE AREA LOOKS
TO GET THE MOST SNOW FROM THIS SYSTEM...BUT WOULD BE AN INCH AT
MOST. IF THE SYSTEM ENDS UP MOVING FARTHER N...SNOWFALL TOTALS WOULD
BE HIGHER.
SATURDAY...MODELS START TO DIVERGE ON SOLUTIONS AT THIS
POINT...ALTHOUGH NOT DRASTICALLY...YET. MAIN DIFFERENCES COME FROM
THE TIMING OF SFC RIDGING MOVING THROUGH. THE GFS IS ON THE SLOWER
END OF GUIDANCE...WITH THE RIDGE AXIS OF THE CWA AT 18Z SAT. THE
ECMWF IS FASTER...WITH THE AXIS OVER THE CWA AT 12Z SAT. THE BIG
DIFFERENCE FROM THIS IS WITH WIND DIRECTIONS. AHEAD OF THE RIDGE
AXIS...WINDS LOOK TO BE MORE NWLY...WHICH WOULD BRING SOME LIGHT LES
NEAR LAKE SUPERIOR E OF MUNISING. WILL GO WITH A MORE BLENDED
SOLUTION RIGHT NOW...WITH THE GREATEST POPS IN NW FLOW AREAS LATE
FRI NIGHT/SAT MORN. HIGHS WILL BE IN THE TEENS TO LOW 20S SAT.
SAT NIGHT THROUGH WED...A SERIES OF UPPER LEVEL DISTURBANCES
MOVES THROUGH DURING THIS TIME...BUT MODELS ARE HAVING A HARD TIME
HANDLING THESE SYSTEMS. NOT ONLY IS MODEL AGREEMENT POOR...RUN TO
RUN DISCONTINUITY IS ALSO A PROBLEM DURING THIS TIME. THESE FACTORS
LEAD TO WELL BELOW NORMAL CONFIDENCE IN THIS PART OF THE FORECAST.
OVERALL...STUCK WITH CONSENSUS MODEL BLENDS FOR THIS PERIOD.
THE GENERAL FEEL FROM THE MODELS IS THAT A LOW PRESSURE SYSTEM WILL
MOVE INTO THE NRN PLAINS SAT NIGHT INTO SUN. THIS LEADS TO
INCREASING TEMPS IN THE SW FLOW WAA REGIME AHEAD OF THE SYSTEM. THE
BEST CHANCE FOR PRECIP CURRENLTY LOOKS TO BE SAT NIGHT INTO
SUN...BUT AS STATED BEFORE CONFIDENCE IS LIMITED.
A PERIOD OF DRIER WEATHER WILL PROBABLY RESULT LATE MON OR TUE AS
UPPER LEVEL RIDGING MOVES OVER THE CWA. MODELS THEN SHOW A SHARP
UPPER TROUGH MOVING TO THE CENTRAL CONUS WED...WHICH WOULD RESULT IN
PRECIP OVER PARTS OF THE REGION.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
BEHIND AN ARCTIC COLD FRONT OVERNIGHT...NORTHWEST WINDS WILL
INCREASE AT ALL THREE SITES...FAVORING MDT/HVY LES AT IWD AND CMX.
THE COMBINATION OF HEAVY LES AND STRONGER WINDS WILL SIGNIFICANTLY
REDUCE VIS AT CMX DURING THE OVERNIGHT HOURS. LES SHOULD BEGIN TO
EASE SLIGHTLY AROUND 18Z ON THURSDAY AS WINDS BEGIN TO BACK TO THE
WEST AND DRIER AIR MOVES INTO THE AREA. EXPECT CONDITIONS TO IMPROVE
TO VFR BY LATE AFTERNOON AT KSAW/KIWD AS A RIDGE BUILDS INTO THE
AREA AND WINDS BACK WSW. HOWEVER...A MORE FAVORABLE TRAJECTORY
ACROSS LAKE SUPERIOR WILL LIKELY BRING HEAVIER LAKE EFFECT SNOW
SHOWERS BACK INTO KCMX DURING THE EVENING.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GOING S GALES UP TO 35 KTS OVER ERN LK SUP THIS EVNG STILL APPEAR ON
TRACK WITH SHARPENING PRES GRADIENT/AREA OF PRES FALLS PASSING TO
THE N. AS THE SFC LO PASSES W-E LATE TNGT INTO THU...EXPECT SHARP
WSHFT TO THE NW. INFLUX OF BITTERLY COLD AIR WILL ENHANCE MIXING OF
WINDS UP TO 40-45 KTS JUST ABOVE THE SURFACE...GALES WILL DEVELOP IN
MOST AREAS. WITH HI WAVES AS WELL...EXPECT HEAVY FREEZING SPRAY OVER
THE ENTIRE LAKE. THE STRONGEST WINDS WILL TEND TO DIMINISH ON THU
AFTERNOON. HIGH PRESSURE WILL BRIEFLY MOVE THROUGH THURSDAY NIGHT
BEFORE A WEAK LOW PRESSURE SYSTEM MOVES OVER LAKE SUPERIOR ON FRIDAY.
HIGH PRESSURE WILL RETURN ON SATURDAY...THEN WILL MOVE EAST SATURDAY
NIGHT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS LOW PRESSURE
SYSTEM LOOKS TO MOVE INTO THE AREA SUNDAY NIGHT INTO MONDAY BEFORE
MOVING EAST MONDAY NIGHT. THERE IS STILL A LARGE AMOUNT OF
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084.
LAKE EFFECT SNOW WARNING FROM 7 AM THIS MORNING TO 1 AM EST
FRIDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST FRIDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST THURSDAY FOR MIZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 AM THIS MORNING TO 7 AM EST
FRIDAY FOR LSZ243>251-264>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ266-267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ249>251-264-265.
GALE WARNING UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR LSZ162-
263.
GALE WARNING FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON
FOR LSZ242>245-248.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ FRIDAY
FOR LSZ162-240>242-263.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ240-
241.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
LMZ221-248-250.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
842 PM MST FRI JAN 20 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
NO APPARENT PRECIPITATION UPSTREAM AND THE HRRR MODEL KEEPS OUR
AREA DRY TONIGHT...SO REMOVED POPS FROM MOST OF THE AREA...EXCEPT A
SLIGHT CHANCE STRIP ALONG THE INTERNATIONAL BORDER. HOWEVER
TEMPERATURES UPSTREAM HAVE WARMED CONSIDERABLY. THE NAM12 MODEL
WAS USED FOR THE DIURNAL TRENDS FOR TONIGHT AND SATURDAY DUE TO
EXPECTED RISING TEMPERATURES FROM THE SW. BLENDED THE HRRR WINDS
INTO THE GRIDS TO INCREASE WINDS IN FAVORED AREAS FOR SE
DIRECTION. THE 00Z SOUNDING REVEALED 850MB WARMING WITH
TEMPERATURES ABOVE 0*C. THIS LOOKS GOOD FOR LIGHT FREEZING
PRECIPITATION SATURDAY MORNING. THE GRIDS ALREADY MENTION THIS. SCT
PREVIOUS DISCUSSION...
WARMER CONDITIONS ARE EXPECTED THIS TERM WITH ABOVE NORMAL
READINGS EXPECTED FOR THE FIRST TIME SINCE SUNDAY.
A STRONG PACIFIC SYSTEM HAS PUSHED ONSHORE IN THE PACIFIC NW WITH A
WARM FRONT NOW MOVING NE THROUGH SW MONTANA. THIS FRONT IS EXPECTED
TO CONTINUE NE ALLOWING TEMPS TO RISE TONIGHT. 850 MB TEMPS RISE
SIGNIFICANTLY AS THE REMAINING ARCTIC AIR-MASS GETS NUDGED TO OUR
NE...WITH READINGS OVER GLASGOW RISING FROM ABOUT -12*C THIS
AFTERNOON TO +3*C SATURDAY MORNING. LOW PRESSURE WILL BEGIN TO
DEVELOP OVER SOUTHERN ALBERTA SATURDAY AS THE UPPER TROUGH MOVES IN.
THE MODELS THEN TAKE THIS LOW EAST NEAR THE INTERNATIONAL
BORDER...FAR ENOUGH NORTH FOR THE MILD PACIFIC AIR-MASS TO FLOOD INTO
THE AREA SATURDAY. OF COURSE SNOW-COVER WILL TEMPER THIS WITH
FURTHER COOLING IN THE NORTHERN ZONES DUE TO LACK OF MIXING.
MOISTURE AHEAD OF THIS SYSTEM LOOKS MINIMAL SO SLIGHT CHANCE POPS
LOOK GOOD FOR NOW. MODELS SEEM TO PUT A FINGER THOUGH ON SOME
DEVELOPMENT SATURDAY AFTERNOON IN THE SOUTHEAST ZONES. THIS AREA
QUICKLY MOVES EAST TO CREATE A HEADACHE FOR AREAS THERE.
THE UPPER TROUGH LATE SATURDAY INTO SUNDAY WRAPS UP A
BIT...ESPECIALLY ON THE GFS. THIS MODEL HAS BEEN CONSISTENT AND
KNOCKS TEMPS BACK DOWN ACROSS THE AREA...AND MIXING NW WINDS TO
THE SURFACE AS WELL. SOME SNOW-SHOWER ACTIVITY CAN BE EXPECTED
TOO...SPREADING FROM NW TO SE DURING THE MORNING. SNOWFALL LOOKS
TO BE LESS THAN AN INCH. JAMBA
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
NOT TOO MANY CHANGES TO THE LONG TERM...WITH THE MAIN FOCUS BEING
THE RETURN OF THE POSSIBILITY OF ABOVE AVERAGE TEMPERATURES NEXT WEEK.
BRIEF RIDGING STILL LOOKS TO MOVE IN EARLY IN THE WORK
WEEK...FOLLOWED BY A SERIES OF SHORTWAVE TROUGHS.
DECIDED TO RAISE TEMPS A BIT FOR NEXT WEEK DUE TO THE MAJORITY OF
MODEL GUIDANCE HINTING TOWARDS WARMER TEMPERATURES COMPARED TO
PREVIOUS RUNS. THE CHALLENGE WILL STILL BE FIGURING OUT JUST HOW WARM
WE WILL GET...ESPECIALLY WITH A FEW BRIEF SHOTS OF COLD AIR WITH
THE PASSING SHORTWAVES AND CORRESPONDING COLD FRONTS. ALTHOUGH
WINDS STILL LOOK TO BE STRONG LATER IN THE PERIOD...THE AMOUNT OF
MIXING STILL MAY PREVENT US FROM BRINGING THE WARMER AIR DOWN TO
THE SURFACE. FORECASTED HIGHS ARE STILL A BIT BELOW MOST MODEL
SOLUTIONS.
WEDNESDAY STILL LOOKS TO BE THE WARMEST DAY NEXT WEEK...WITH THE
GFS BRINGING 850 TEMPS AROUND 4C TO 8C OVER THE CWA. HOWEVER...THE
12Z ECMWF SUGGESTS THAT WEDNESDAY AND THURSDAY LOOK TO BE
WARM...WITH THURSDAY BEING THE WARMER OF THE TWO DAYS. 850 TEMPS
ARE JUST A BIT HIGHER ON THURSDAY ACCORDING TO THE ECMWF BY ABOUT
2C TO 4C COMPARED TO WEDNESDAY. EITHER WAY...NEXT WEEK STILL LOOKS
TO BE A WELCOMED RETURN TO WARMER TEMPERATURES. BARNWELL
PREVIOUS LONG TERM DISCUSSION...PATTERN RETURNS TO WHAT HAS BEEN
COMMON THIS WINTER...ZONAL FLOW OFF THE PACIFIC WITH A SERIES OF
WEAK RIDGES AND TROF...AND ARCTIC AIRMASS STAYING WELL TO THE
NORTH. MODEL TIMING OF THE FEATURES NOT TOO FAR OFF FROM EACH
OTHER...ALTHOUGH THIS DOES SLIP TOWARD THE END OF THE FORECAST
PERIOD.
UPPER TROF EXITING THE REGION SUNDAY NIGHT WITH RIDGE SLIDING
ACROSS THE STATE ON MONDAY WITH ANOTHER TROF PUSHING THROUGH THE
PACIFIC NORTHWEST. COLD FRONT IS PUSHED INTO THE STATE MONDAY
NIGHT AS UPPER TROF TRACKS ALONG THE CANADIAN BORDER.
JET PUNCHES INTO WESTERN CANADA BEHIND THE TROF ON TUESDAY
NIGHT..DEVELOPING INTO A STRONG CHINOOK ACROSS MONTANA ON
WEDNESDAY. AS JET DIVES INTO THE NORTHERN PLAINS...COLD FRONT
DROPS THROUGH MONTANA...AND ENOUGH DYNAMICS AND MOISTURE FOR A
LITTLE PRECIPITATION ON WEDNESDAY. PATTERN REPEATS FOR THURSDAY
INTO THURSDAY NIGHT...ALTHOUGH AIRMASS SLIGHTLY COLDER BEHIND THIS
SECOND COLD FRONT.
POTENTIAL FOR WINDY CONDITIONS WILL BE INCREASING ALTHOUGH MIXING
WILL CONTINUE TO BE A PROBLEM...ESPECIALLY WITH INCREASED SNOW
COVER IN CONTRAST TO EARLIER IN THE MONTH. EBERT
&&
.AVIATION...
THERE WILL BE A SCATTERED TO BROKEN LAYER AROUND 2K FT AGL OVER
PARTS OF THE FORECAST AREA TONIGHT...OTHERWISE MAINLY VFR WITH
BROKEN TO OVERCAST LAYERS ABOVE 8K FT AGL. E WINDS 10 TO 15 KT AT
GGW. SLIGHT CHANCE OF A LITTLE LIGHT FREEZING RAIN LATE TONIGHT AND
SATURDAY MORNING. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
510 PM CST FRI JAN 20 2012
.AVIATION...00Z KGRI TAF. CEILINGS ARE GOING TO BE A TOUGH CALL
THIS EVENING. SOME STRATUS ARE HEADING TOWARD THE TERMINAL FROM
THE NORTH...BUT ISENTROPIC DOWNGLIDE WILL BE COMPETING AGAINST
THE STRATUS HOLDING TOGETHER FOR LONG. LOOKING AT THE LATEST
SATELLITE DATA AND SPEED TOOLS...IT APPEARS THAT THE STRATUS
SHOULD ARRIVE A BIT OVER AN HOUR AFTER THIS FORECAST IF
VALID...BUT WITH ISENTROPIC DOWNGLIDE...WILL LIKELY ONLY HOLD
TOGETHER THROUGH THE EVENING AND THEN SCATTER BY THE EARLY
OVERNIGHT. WIND WILL SWITCH FROM THE NORTH TO THE SOUTH OVERNIGHT
AS A SURFACE HIGH SLIDES EAST. SOUTH WIND CAN GET A BIT GUSTY BY
SATURDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT INCREASES.
&&
.PREV DISCUSSION... /ISSUED 318 PM CST FRI JAN 20 2012/
SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...HEINLEIN
SHORT TERM...BRYANT
LONG TERM...KING
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1249 PM CST THU JAN 19 2012
.UPDATE...
ARCTIC HIGH PRESSURE CONTINUES TO DOMINATE THE REGION. TEMPS HAVE
BEEN SLOW TO RISE THIS MORNING...AND HAVE DROPPED HIGHS AND
HOURLY TEMPS FOR TODAY. FOLLOWED CLOSE TO RUC GUIDANCE...WHICH
HAS THE BEST CURRENT POSITION BASED ON LATEST OBS.
&&
.AVIATION...
VFR CONDITIONS TODAY AS ARCTIC HIGH PRESSURE DOMINATES THE
PLAINS. WARM AIR WILL LIFT NORTHEAST AS CENTER OF HIGH SLIDES TO
THE SOUTHEAST OVERNIGHT. MODELS INCREASE LL RH VALUES LATE
TONIGHT...WITH MOS GUIDANCE SHOWING MVFR/IFR CIGS DEVELOPING OVER
NORTHERN AND CENTRAL NEBRASKA. HIGHER CONFIDENCE WILL SEE AN
IMPACT AT KVTN...HOWEVER MODELS ARE FASTER THAT ACTUALLY
HAPPENING WITH RETREATING THE COLD AIR. THIS MAY RESULT IN
STRATUS IMPACTING PARTS OF SW NEBRASKA...AND THE KLBF TERMINAL.
WILL MONITOR FOR POSSIBLE ADDITION TO LBF TAF. ANY STRATUS THAT
DOES DEVELOP WILL BE SLOW TO LIFT TOMORROW MORNING AND EARLY
AFTERNOON.
&&
.PREV DISCUSSION.../ISSUED 341 AM CST THU JAN 19 2012/
SYNOPSIS... HAND ANALYSIS OF THE 19.00Z H25 AND H5 LEVELS REVEALS
NORTHWESTERLY FLOW ACROSS THE NORTHERN AND CENTRAL HIGH
PLAINS...WITH STRONG UPPER LEVEL JET SUPPORT OF GREATER THAN 150
KTS EDGING FROM THE EASTERN CASCADES TOWARD THE BLACK HILLS REGION
OF SOUTH DAKOTA. A SHORTWAVE TROUGH WAS ANALYZED IN THE MID LEVELS
NEAR LAKE SUPERIOR...WITH ANOTHER WAVE CLOSING IN ON THE PACIFIC
NORTHWEST. AT THE SURFACE...COLD ARCTIC AIR HAS ONCE AGAIN
FILTERED ACROSS THE SAND HILLS REGION OF NEBRASKA...WITH SUB ZERO
TEMPERATURES ALONG THE NIOBRARA RIVER VALLEY EARLY THIS MORNING.
FURTHER SOUTH...SINGLE DIGIT READINGS ARE THE NORM. REGIONAL
RADARS ARE INTERROGATING A BAND OF LIGHT SNOW ACROSS WESTERN SOUTH
DAKOTA...BUT GENERALLY VOID OF PRECIPITATION ELSEWHERE.
DISCUSSION...
ANOTHER TRICKY TEMPERATURE FORECAST IS IN STORE FOR THIS AFTERNOON
AS THE ARCTIC FRONT RETREATS NORTH AND EAST...AND SOUTHERLY FLOW
RETURNS OVER SOUTHERN AND WESTERN NEBRASKA. THE MODELS INDICATE
WARMING ALOFT...AS THE CONSENSUS SUGGESTS H85 TEMPERATURES GENERALLY
RANGING FROM 8C ACROSS SOUTHWEST NEBRASKA TO -8C OVER NORTH CENTRAL
NEBRASKA BY 00Z FRIDAY. HOWEVER CLOSER TO THE SURFACE...H925
TEMPERATURES REMAIN BELOW 0C ACROSS MUCH OF THE CWA THROUGH 00Z
FRIDAY...WITH -2 AT LBF AND -12C AT ONL. THE 00Z UNR SOUNDING
INDICATES ABOUT 2-3K FT DEPTH OF THE COLDER AIR...SO ITS GONNA TAKE
SOME MIXING TO SCOUR OUT THE LAYER...BUT UNFORTUNATELY WITH SOUTH TO
SOUTHEASTERLY FLOW...MIXING WILL BE RATHER LIMITED TODAY. SO ONLY
THE FAR WESTERN PORTIONS OF THE CWA MAY SEE TEMPERATURES ABOVE 0C
THIS AFTERNOON...ELSEWHERE TEMPERATURES WILL RANGE FROM THE LOW
TEENS OVER NORTH CENTRAL NEBRASKA TO THE LOW 30S AT LBF. FOR
TONIGHT...AGAIN WARMING ALOFT WILL OCCUR...BUT WITH THE SHALLOW
ARCTIC AIR MASS IN PLACE...STILL LOOKING FOR BELOW AVERAGE LOWS OVER
MUCH OF THE CWA...WITH LOWS RANGING FROM THE SINGLE DIGITS ACROSS
NORTH CENTRAL NEBRASKA...TO POSSIBLY LOW TO MID 20S ACROSS SOUTHWEST
NEBRASKA. MODELS CONTINUE TO INDICATE A CHANCE OF PRECIPITATION
ALONG NORTHERN NEBRASKA OVERNIGHT TONIGHT AS WELL. BEST FORCING AND
SUPPORT FOR THE PRECIPITATION HAS TRENDED NORTH INTO SOUTH DAKOTA
THE PAST COUPLE MODEL RUNS...WITH FAVORABLE SATURATION PRESSURE
DEFICITS NORTH OF THE CWA. BUT FAVORABLE UPPER LEVEL JET SUPPORT
WILL BE IN THE REGION...AND MODEL SOUNDINGS INDICATE SUFFICIENT
SATURATION OVER NORTHERN NEBRASKA...SO NOT READY TO PULL THE PLUG ON
PRECIPITATION CHANCES YET. WILL LEAVE POPS AT CHANCE TO LOW END
LIKELY ACROSS NORTH CENTRAL NEBRASKA FOR NOW...BUT QPF AMOUNTS LOOK
LIGHT AT BEST. MODEL SOUNDINGS ALSO INDICATE THE POTENTIAL FOR A
MIXED BAG OF PRECIPITATION...WITH POSSIBLY SOME IP OR ZR AS WAA
PUSHES TEMPERATURES ALOFT ABOVE 0C ACROSS NORTHERN NEBRASKA...THIS
WILL NEED TO BE RE-EVALUATED WITH THE NEWEST MODEL GUIDANCE AND FOR
NOW WILL LEAVE AS -SN AS TEMPERATURE CONFIDENCE IS LOW. ARCTIC
FRONT PLUNGES SOUTH ONCE AGAIN ON FRIDAY...AND AGAIN A DIFFICULT
HIGH TEMPERATURE FORECAST IS IN STORE. WHAT IS CERTAIN IS NORTHERN
NEBRASKA WILL BE BELOW AVERAGE...WITH HIGHS IN THE TEENS...SOUTH OF
INTERSTATE 80...AND OVER THE HIGHER TERRAIN OF THE WEST...40S MAY BE
POSSIBLE. THE ARCTIC AIR MASS MODIFIES AND BUILDS EAST AGAIN ON
SATURDAY...AS SOUTHERLY FLOW RETURNS TO THE PLAINS. H925
TEMPERATURES BY LATE SATURDAY AFTERNOON SHOULD PUSH WELL ABOVE 0C
FOR MUCH OF THE CWA...WITH THE EXCEPTION OF OUR FAR EASTERN
ZONES...SO HIGHS SHOULD RANGE FROM THE LOW 30S OVER THE EAST...TO
NEAR 50 ACROSS THE FAR WEST. SUNDAY MAY BE INTERESTING...THE MODELS
HAVE BEEN ADVERTISING A RAPIDLY ADVANCING MID TO UPPER TROUGH
PASSAGE OVER THE LAST FEW RUNS. THE EUROPEAN SOLUTION THIS EVENING
IS NOW INDICATING A DEEPER AND POTENTIALLY MORE SIGNIFICANT PASSAGE
FOR THE CWA. THIS NEW SOLUTION WOULD GIVE THE CWA WIDESPREAD
ACCUMULATING QPF...NOT SIGNIFICANT AMOUNTS...BUT WITH THE DRY WINTER
THUS FAR...ANY ACCUMULATIONS WOULD BE APPRECIATED. GFS AND NAM
CONTINUE TO TARGET NORTH OF THE CWA. THE EURO PRECIP FIELD MAY BE
OVERDONE...BUT WORTHY OF AT LEAST A SLIGHT CHANCE MENTION FOR NOW.
AS FOR PTYPE...TEMPERATURES AT THIS POINT IN TIME LOOK TO BE WARM
ENOUGH FOR ALL RAIN OVER MUCH OF THE CWA...BUT GIVEN IT/S
JANUARY...WILL GO WITH RAIN OR SNOW FOR NOW. FOR THE START IF THE
WORK WEEK...SLIGHTLY WARMER AIR SHOULD RETURN EARLY NEXT WEEK WITH
HIGHS AT OR SLIGHTLY ABOVE CLIMO. ANOTHER QUICK MOVING TROUGH WILL
CROSS THE NORTHERN PLAINS ON TUESDAY...BRINGING ANOTHER
SHOT...ALBEIT SLIGHT CHANCE AT THIS POINT IN TIME...OF
PRECIPITATION...MADE ON MINOR ADJUSTMENTS TO THE EXTENDED BEYOND
SUNDAY AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE/AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1123 AM CST THU JAN 19 2012
.AVIATION...18Z TAF. ARCTIC HIGH PRESSURE WILL SLIDE TO THE EAST
TODAY INTO TONIGHT. THIS WILL ALLOW RETURN FLOW...AND WARMER AIR
TO RETURN TO THE AREA. AS THE WARMER AIR RETURNS...THERE ARE SOME
SIGNS STRATUS COULD TRY TO DEVELOP OVERNIGHT...BUT THE 12Z NAM IS
NOW SLOWER IN BRINGING THE LOW CLOUDS TO KGRI. IN FACT...IT GENERALLY
SUGGESTS THAT MID AND HIGH LEVEL CLOUDS WILL DOMINATE UNDER THE
H85 WARM AIR ADVECTION...HOWEVER ONCE THE ARCTIC AIR MOVES SOUTH
AGAIN ON FRIDAY...STRATUS COULD COME WITH IT. WILL HOLD ONTO A VFR
FORECAST THROUGH TONIGHT...BUT WILL CARRY SCATTERED CLOUDS AROUND
2500FT IN ORDER TO SUGGEST THERE IS SOME CHANCE LOWER CLOUDS COULD
TRY TO DEVELOP OVERNIGHT. WILL GO WITH AN MVFR CEILING LATE IN THE
PERIOD...WHICH IS IN LINE WITH THE NAM...AS THE ARCTIC AIR AGAIN
INVADES THE AREA. WINDS WILL START OUT LIGHT AND VARIABLE...BUT
SHOULD TURN SOUTHERLY THIS AFTERNOON AS THE HIGH SLIDES EAST.
WINDS WILL BECOME NORTHERLY AGAIN LATE IN THE PERIOD AS ANOTHER
COLD FRONT DROPS SOUTH ACROSS THE TERMINAL LOCATION.
&&
.PREV DISCUSSION... /ISSUED 1027 AM CST THU JAN 19 2012/
UPDATE...SENT A QUICK UPDATE TO ADJUST THE HOURLY TEMPERATURE
CURVE TO BETTER REFLECT REALITY...OTHERWISE THE REMAINDER OF THE
FORECAST LOOKS ON TRACK FOR TODAY.
PREV DISCUSSION... /ISSUED 639 AM CST THU JAN 19 2012/
UPDATE...JUST RAN A QUICK UPDATE TO TABULAR AFM/PFM PRODUCTS AND
WEB-BASED PRODUCTS TO BRING NEXT SEVERAL HOURS OF TEMP/DEWPOINT
TRENDS MORE IN LINE WITH CURRENT OBS...AS COLDER AND DRIER AIR HAS
PUSHED MORE AGGRESSIVELY SOUTHWARD INTO SOUTHERN PORTIONS OF THE
CWA THAN EXPECTED EVEN A FEW HOURS AGO. ONLY MODEL/GUIDANCE REALLY
PROVING USEFUL FOR THESE VERY SHORT TERM TRENDS IS GFS LAMP
GUIDANCE. WIND CHILLS BETWEEN -10 AND -15 WILL BE WIDESPREAD
ACROSS MOST ALL NEB ZONES FOR THE NEXT FEW HOURS...WITH KS ZONES
MORE SO -5 TO -10. ALTHOUGH NO CHANGES WERE MADE TO AFTERNOON HIGH
TEMPS AT THIS TIME...INTERESTING TO NOTE THAT BOTH THE 09Z RUC AND
HRRR SUGGEST THAT THE TRI-CITIES WILL RECOVER ENOUGH TO POSSIBLY
REACH 20 THIS AFTERNOON...BUT THIS SEEMS TOO OPTIMISTIC AT THIS
TIME AND WILL STICK WITH GOING FORECAST.
PREV DISCUSSION... /ISSUED 451 AM CST THU JAN 19 2012/
SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS CONTINUES TO BE TEMPERATURE TRENDS...WITH THE NEXT
REGIONAL SNOW EVENT FROM THURSDAY NIGHT INTO FRIDAY STILL PROGGED
TO MISS MOST...IF NOT ALL OF THE CWA TO THE NORTHEAST...FOCUSING
ALONG AN AXIS FROM SD THROUGH NORTHEAST NEB/NORTHERN IA. THAT
BEING SAID...ALTHOUGH NOT OVERLY CONCERNED AT THIS POINT...WILL
NEED TO MONITOR LOW LEVEL MOISTURE TRENDS CLOSELY LATE THURS NIGHT
INTO FRIDAY MORNING TO MAKE SURE THAT NO LIGHT FREEZING DRIZZLE
TRIES TO SNEAK UP ON US.
09Z OBJECTIVE SURFACE ANALYSIS REVEALS THAT THE WELL ADVERTISED
ARCTIC COLD FRONT HAS MADE STEADY PROGRESS SOUTHWARD ACROSS THE
CWA THROUGH THE NIGHT...PUSHED ALONG BY A BROAD 1024MB HIGH
CENTERED FROM MT TO NORTHERN SD. TEMPERATURES AT 09Z RANGED FROM 2
AT ORD...TO 18 AT BELOIT. ADDING TO THE INVADING BITTERNESS ARE
STEADY NORTH-NORTHEAST BREEZES OF 10-20 MPH...YIELDING WIND CHILL
VALUES RANGING FROM -10 TO -15 NORTH OF I-80...TO NEAR ZERO IN THE
SOUTH. DESPITE PLENTIFUL MID LEVEL RADAR RETURNS EARLIER THE NIGHT
ACROSS THE NORTHEAST...IT IS LIKELY THAT FLURRY ACTIVITY DID NOT
MATERIALIZE ACROSS THE NORTHEAST. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA FEATURE VERY FAST NORTHWEST FLOW BISECTING
THE CONUS FROM NORTHWEST TO SOUTHEAST...HIGHLIGHTED BY A 140+KT
300MB JET STREAK CUTTING ACROSS EASTERN NEB. ALTHOUGH THE PRIMARY
MID LEVEL SHORTWAVE/500MB VORT MAX OF NOTE IS ALREADY WELL
NORTHEAST INTO THE GREAT LAKES...LIFT ASSOCIATED WITH THE UPPER
JET STREAK HAS GENERATED PLENTIFUL CIRRUS OVER MAINLY NEB ZONES
OVERNIGHT...BUT KEEPING PRIMARY ZONE OF MID LEVEL
SATURATION/POSSIBLE LIGHT SNOW PRODUCTION OFF TO THE NORTH AND
EAST.
TODAY...THE AFOREMENTIONED STRONG UPPER JET AXIS DRIFTS
NORTHEAST...WITH ITS CENTER ALONG AN AXIS FROM CENTRAL ND TO
NORTHERN IL BY 00Z THIS EVENING. AS A RESULT...THE EXTENSIVE HIGH
LEVEL CLOUD COVER ACROSS MOST OF THE CWA SHOULD GRADUALLY SCATTER
OUT AND/OR LIFT NORTHEAST AS WELL...WITH AT LEAST PARTLY CLOUDY
SKIES ANTICIPATED MOST AREAS FOR THIS AFTERNOON. EVEN IF THE SUN
IS OUT...IT WON/T DO A WHOLE LOT TO MASK WHAT IS ALMOST CERTAINLY
TO BE THE OVERALL COLDEST DAY OF THE WINTER SO FAR FOR MOST OF THE
CWA. AS THE DAY WEARS ON...THE CENTER OF THE SURFACE HIGH WILL
MIGRATE INTO MN/IA...ALLOWING BREEZES TO GRADUALLY DIMINISH INTO
THE 5-10 MPH RANGE FOR THIS AFTERNOON AS THEY GRADUALLY SHIFT FROM
MORE NORTHERLY TO MORE EASTERLY/SOUTHEASTERLY BY LATE IN THE DAY.
AS FOR TEMPS...YET AGAIN OPTED TO LOWER HIGHS BY 2-5 DEGREES FROM
PREVIOUS FORECAST IN MOST AREAS...LEANING TOWARD THE COLDER MAV
GUIDANCE. THIS YIELDS HIGHS RANGING FROM ONLY 10-13 DEGREES IN THE
NORTHEAST CWA...TO MID 20S FAR SOUTH AND WEST WHERE THE SOUTHEAST
FLOW AROUND THE HIGH SHOULD HELP MODERATE THINGS SOMEWHAT. AS FOR
WIND CHILLS THIS MORNING...VALUES WILL CONTINUE TO RANGE BETWEEN
-10 AND -17 ACROSS MUCH OF THE NORTHEAST 1/2 OF THE CWA THROUGH AT
LEAST MID-MORNING...WHICH WILL BE ABOVE ADVISORY CRITERIA OF -20
BUT NOT BY MUCH. ITS CLOSE ENOUGH THAT WILL PUT A MENTION IN THE
HAZARDOUS WEATHER OUTLOOK.
TONIGHT...THE NEXT BATCH OF BROAD...LOW AMPLITUDE SHORTWAVE ENERGY
QUICKLY APPROACHES THE CENTRAL CONUS FROM THE NORTHWEST. WITHIN
THE ENTRANCE REGION OF THE PRIMARY UPPER JET AXIS MIGRATING ACROSS
THE UPPER MISS VALLEY/GREAT LAKES...AN IMPRESSIVE ZONE OF
ISENTROPIC LIFT/MID LEVEL CONVERGENCE WILL SET UP ALONG AND NORTH OF
THE PRIMARY LOW-MID LEVEL TEMPERATURE GRADIENT CENTERED FROM SD
INTO NORTHEAST NEB/IA. THIS WILL BE THE OBVIOUS FOCUS FOR THE
START OF A MEASURABLE SNOW EVENT FOR THOSE AREAS. ALTHOUGH IT IS
SEEMING MORE AND MORE LIKELY THAT THE CWA WILL MISS OUT ON THIS
ACTION...PREVIOUS FORECAST HAD SOME LOW POPS ACROSS THE
NORTHEAST...AND WILL CONTINUE THIS MENTION AFTER MIDNIGHT FOR
MAINLY THE NORTHEAST 1/5 OF THE CWA JUST IN CASE THE FAR SOUTHERN
EDGE OF THIS ACTIVITY SLIPS IN. ANY ACCUMULATIONS...IF ANY...WOULD
NOT AMOUNT TO MORE THAN A FEW TENTHS. INTERESTINGLY...IF ANYTHING
DOES HAPPEN TO FALL IN THE FAR NORTH TONIGHT...IT MIGHT ACTUALLY
FAVOR THE FORM OF LIGHT SLEET BASED ON FORECAST SOUNDINGS...BUT
WILL LEAVE IT AS SNOW MENTION FOR NOW. HAVE ALSO BEEN GROWING A
BIT LEARY OF POSSIBLE LIGHT FREEZING DRIZZLE ACROSS NORTHERN
PORTIONS OF THE AREA GIVEN THE GOOD LOW LEVEL WARM ADVECTION...BUT
THINKING AT THIS POINT IS THAT ANY POTENTIAL STRATUS LAYER WOULD
BE TOO SHALLOW TO SUPPORT THIS. SOMETHING TO WATCH. AS FOR LOW
TEMPS...CHANGED THEM LITTLE...ALTHOUGH CONFIDENCE IN HOURLY TRENDS
IS QUITE LOW AS TEMPS COULD EASILY DISPLAY STEADY/SLOWLY RISING
CHARACTERISTICS AS BREEZES TURN SOUTHERLY. KEPT IT SIMPLE FOR NOW
THOUGH...INDICATING MOST AREAS BOTTOMING OUT BETWEEN 9 AND 15
DEGREES...ALTHOUGH THIS MIGHT END UP BEING EARLIER IN THE NIGHT
VERSUS LATER FOR SOME PLACES.
FRIDAY...THE MAIN BATCH OF SHORTWAVE ENERGY PASSES THROUGH THE
CENTRAL PLAINS...ALTHOUGH THE UPPER JET FORCING CONTINUES TO
DIRECT THE MAIN PRECIP EVENT FROM EASTERN SD INTO NORTHERN
IA/SOUTHERN MN AND POINTS EAST. THUS LEFT PRECIP MENTION OUT OF
THE FORECAST...ALTHOUGH ONCE AGAIN WILL HAVE TO MONITOR DEPTH OF
POSSIBLE STRATUS LAYER CLOSELY FOR OUTSIDE CHANCE OF SNEAKY LIGHT
FREEZING DRIZZLE THREAT...BUT JUST SEEMS RATHER UNLIKELY AT THIS
JUNCTURE. AS FOR HIGH TEMPS...THE SOUTHERN EDGE OF THE ARCTIC COLD
FRONT WILL PLAY A BIG ROLE AS IT IS PROGGED TO DROP RIGHT BACK
SOUTH ACROSS THE CWA OVER THE COURSE OF THE DAY...ALTHOUGH THE GFS
IS MUCH MORE AGGRESSIVE THAN THE LATEST ECMWF/NAM REGARDING WITH
THIS COLD PUSH. CONSENSUS OF SEVERAL MODELS/GUIDANCE WAS TO...YOU
GUESSED IT...LOWER TEMPS SEVERAL DEGREES...AND BUMPED DOWN 3-5
DEGREES MOST AREAS...NOW ADVERTISING MID 20S NORTHEAST TO UPPER
30S SOUTHWEST. INTERESTING TO NOTE THAT THIS DAY HAS NOW TRENDED
15+ DEGREES COLDER THAN FORECASTS ISSUED JUST 2-3 DAYS AGO.
FRIDAY NIGHT...IT REMAINS DRY AS A SURFACE RIDGE AXIS SLIDES
ACROSS THE CENTRAL PLAINS...AND A BRIEF BIT OF SHORTWAVE RIDGING
SETS IN ALOFT. ASSUMING LIMITED CLOUD COVER...TEMPS COULD TAKE A
DECENT TUMBLE...AND LOWERED LOWS 5 DEGREES MOST AREAS WITH SINGLE
DIGITS ABOVE ZERO NOW IN PLACE FOR MUCH OF THE CWA.
SATURDAY...THE NEXT...MORE VIGOROUS MID LEVEL WAVE STARTS MAKING
ITS WAY ACROSS THE CENTRAL/SOUTHERN ROCKIES...INDUCING SURFACE
PRESSURE FALLS AND RAMPING UP SOUTH-SOUTHEAST BREEZES INTO AT
LEAST THE 15-20 MPH SUSTAINED RANGE. DESPITE THIS SOUTHERLY
WIND...THE DIRECTION IS NOT OVERLY CONDUCIVE FOR SIGNIFICANT
WARMING...AND HAVE ONLY INDICATED A MODEST WARM-UP OVER
FRIDAY...WITH HIGHS RANGING FROM LOW 30S FAR EAST TO LOW 40S FAR
WEST.
SATURDAY NIGHT...LEFT THIS PERIOD DRY...AT LEAST FOR NOW...AS THE
INCOMING SHORTWAVE CONTINUES TO AMPLIFY/STRENGTHEN AS A 100+KT
UPPER JET STARTS TO ROUND THE BASE INTO THE CENTRAL PLAINS. ONLY
THING KEEPING POPS FROM BEING INSERTED AT THIS POINT IS SUGGESTION
THAT A MID LEVEL DRY SLOT WILL BE IN PLACE ACROSS THE CWA...WITH
MAIN FORCING/MID LEVEL DEFORMATION AXIS HOLDING JUST OFF TO THE
NORTH/WEST...THUS HOLDING OFF BETTER PRECIP CHANCES UNTIL SUNDAY
AS DISCUSSED BELOW.
LONG TERM...SUNDAY THROUGH WEDNESDAY. PATTERN REMAINS
PROGRESSIVE THROUGH THE EXTENDED PERIODS WITH CHALLENGE OF TRYING
TO TIME WAVES. BEGINNING ON SUNDAY...A 100+KT JET NOSES EAST FM
THE FOUR CORNERS REGION AND LIFTS NORTHEAST ACROSS THE CENTRAL
PLAINS DEEPENING THE MID/UPPER TROUGH ACROSS THE CENTRAL PLAINS.
THE 00Z ECMWF IS THE STRONGEST/SLOWEST WITH THE SYSTEM ON SUNDAY
AND CLOSES OFF THE H7 LOW...WHEREAS OTHER EXTENDED MODELS SUGGEST
A MORE PROGRESSIVE OPEN WAVE. IN GENERAL...THERE IS CONSENSUS
AMONG MODELS THAT OUR REGION WILL BE UNDER THE INFLUENCE OF A
TROUGH THRU AT LEAST THE FIRST HALF OF THE DAY...OR LONGER IF
SLOWER ECWMF VERIFIES. COOL FRONTAL BOUNDARY WILL SWEEP ACROSS OUR
REGION IN MORNING WITH AN AREA OF LOW CLOUDS/PCPN ACCOMPANYING
SYSTEM AIDED BY ENHANCED UPPER DYNAMICS IN LFQ OF JET. HOW LONG
PCPN/LOW CLOUDS LINGERS IS DEPENDENT ON STRENGTH OF SYSTEM AND IF
SYSTEM MOVES THRU FASTER...CLEARING SKIES/DOWNSLOPE CONDITIONS MAY
AID IN SOME WARMING FOR THE AFTN. IN ADDITION TO THE PCPN
POTENTIAL...MODELS ALSO SUGGEST STRONG WIND POTENTIAL SUNDAY WITH
NAM INDICATING 3HR PRESSURE RISES OF 6MB BEHIND THE FRONT IN
TIGHTENING SFC GRADIENT...WHILE A CORRIDOR OF 50 TO 60KT MID
LEVEL WINDS CROSS OUR REGION. WILL NEED TO MONITOR MODEL TRENDS OF
THIS AS WELL. FOR PCPN TYPE ON SUNDAY...HAVE WENT WITH R/S IN THE
MORNING TRANSITIONING TO RAIN IN AFTN AS TEMPS LOOK TO RISE ABOVE
FREEZING.
HEADING INTO SUNDAY NIGHT...THE TROUGH AXIS DEPARTS AND CONDITIONS
DRY WITH RISING HEIGHTS BEHIND THE EXITING SYSTEM. MODELS ARE STILL
LOOKING DRY MONDAY IN BETWEEN SYSTEMS...AND THEN NEXT WAVE IS PROGGED
TO EMERGE ONTO THE PLAINS ON TUESDAY. THERE IS STILL SOME
UNCERTAINTY ON DEGREE OF MOISTURE WITH THIS NEXT SYSTEM BUT SMALL
CHCS FOR PCPN STILL WARRANTED AS CURRENTLY FORECAST. MILD AIRMASS IN PLACE
SHLD MAINTAIN LIQUID CHCS INITIALLY WITH POTENTIAL FOR CHANGE TO
SNOW IN COOLER AIR WITH FROPA TUESDAY NIGHT.
THE AIRMASS IN GENERAL DURING THE EXTENDED IS NOT OVERLY COLD AND
TEMPS LOOK TO BE MORE DEPENDENT ON CLOUDS/PCPN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1027 AM CST THU JAN 19 2012
.UPDATE...SENT A QUICK UPDATE TO ADJUST THE HOURLY TEMPERATURE
CURVE TO BETTER REFLECT REALITY...OTHERWISE THE REMAINDER OF THE
FORECAST LOOKS ON TRACK FOR TODAY.
&&
.PREV DISCUSSION... /ISSUED 639 AM CST THU JAN 19 2012/
UPDATE...JUST RAN A QUICK UPDATE TO TABULAR AFM/PFM PRODUCTS AND
WEB-BASED PRODUCTS TO BRING NEXT SEVERAL HOURS OF TEMP/DEWPOINT
TRENDS MORE IN LINE WITH CURRENT OBS...AS COLDER AND DRIER AIR HAS
PUSHED MORE AGGRESSIVELY SOUTHWARD INTO SOUTHERN PORTIONS OF THE
CWA THAN EXPECTED EVEN A FEW HOURS AGO. ONLY MODEL/GUIDANCE REALLY
PROVING USEFUL FOR THESE VERY SHORT TERM TRENDS IS GFS LAMP
GUIDANCE. WIND CHILLS BETWEEN -10 AND -15 WILL BE WIDESPREAD
ACROSS MOST ALL NEB ZONES FOR THE NEXT FEW HOURS...WITH KS ZONES
MORE SO -5 TO -10. ALTHOUGH NO CHANGES WERE MADE TO AFTERNOON HIGH
TEMPS AT THIS TIME...INTERESTING TO NOTE THAT BOTH THE 09Z RUC AND
HRRR SUGGEST THAT THE TRI-CITIES WILL RECOVER ENOUGH TO POSSIBLY
REACH 20 THIS AFTERNOON...BUT THIS SEEMS TOO OPTIMISTIC AT THIS
TIME AND WILL STICK WITH GOING FORECAST.
PREV DISCUSSION... /ISSUED 600 AM CST THU JAN 19 2012/
AVIATION...12Z TAF. ARCTIC HIGH PRESSURE WILL SHIFT INTO NORTHERN
IOWA TODAY. NORTHEASTERLY WINDS THIS MORNING WILL BECOME VARIABLE
FOR A FEW HOURS AROUND MIDDAY BEFORE TRANSITIONING TO THE
SOUTHEAST. CLOUD COVER LOOKS TO BE LIMITED TO THE MID AND HIGH
LEVELS FOR MUCH OF THE DAY WITH SOME MVFR TO VFR CIGS POSSIBLE
LATER TONIGHT OR TOWARD FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 451 AM CST THU JAN 19 2012/
SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS CONTINUES TO BE TEMPERATURE TRENDS...WITH THE NEXT
REGIONAL SNOW EVENT FROM THURSDAY NIGHT INTO FRIDAY STILL PROGGED
TO MISS MOST...IF NOT ALL OF THE CWA TO THE NORTHEAST...FOCUSING
ALONG AN AXIS FROM SD THROUGH NORTHEAST NEB/NORTHERN IA. THAT
BEING SAID...ALTHOUGH NOT OVERLY CONCERNED AT THIS POINT...WILL
NEED TO MONITOR LOW LEVEL MOISTURE TRENDS CLOSELY LATE THURS NIGHT
INTO FRIDAY MORNING TO MAKE SURE THAT NO LIGHT FREEZING DRIZZLE
TRIES TO SNEAK UP ON US.
09Z OBJECTIVE SURFACE ANALYSIS REVEALS THAT THE WELL ADVERTISED
ARCTIC COLD FRONT HAS MADE STEADY PROGRESS SOUTHWARD ACROSS THE
CWA THROUGH THE NIGHT...PUSHED ALONG BY A BROAD 1024MB HIGH
CENTERED FROM MT TO NORTHERN SD. TEMPERATURES AT 09Z RANGED FROM 2
AT ORD...TO 18 AT BELOIT. ADDING TO THE INVADING BITTERNESS ARE
STEADY NORTH-NORTHEAST BREEZES OF 10-20 MPH...YIELDING WIND CHILL
VALUES RANGING FROM -10 TO -15 NORTH OF I-80...TO NEAR ZERO IN THE
SOUTH. DESPITE PLENTIFUL MID LEVEL RADAR RETURNS EARLIER THE NIGHT
ACROSS THE NORTHEAST...IT IS LIKELY THAT FLURRY ACTIVITY DID NOT
MATERIALIZE ACROSS THE NORTHEAST. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA FEATURE VERY FAST NORTHWEST FLOW BISECTING
THE CONUS FROM NORTHWEST TO SOUTHEAST...HIGHLIGHTED BY A 140+KT
300MB JET STREAK CUTTING ACROSS EASTERN NEB. ALTHOUGH THE PRIMARY
MID LEVEL SHORTWAVE/500MB VORT MAX OF NOTE IS ALREADY WELL
NORTHEAST INTO THE GREAT LAKES...LIFT ASSOCIATED WITH THE UPPER
JET STREAK HAS GENERATED PLENTIFUL CIRRUS OVER MAINLY NEB ZONES
OVERNIGHT...BUT KEEPING PRIMARY ZONE OF MID LEVEL
SATURATION/POSSIBLE LIGHT SNOW PRODUCTION OFF TO THE NORTH AND
EAST.
TODAY...THE AFOREMENTIONED STRONG UPPER JET AXIS DRIFTS
NORTHEAST...WITH ITS CENTER ALONG AN AXIS FROM CENTRAL ND TO
NORTHERN IL BY 00Z THIS EVENING. AS A RESULT...THE EXTENSIVE HIGH
LEVEL CLOUD COVER ACROSS MOST OF THE CWA SHOULD GRADUALLY SCATTER
OUT AND/OR LIFT NORTHEAST AS WELL...WITH AT LEAST PARTLY CLOUDY
SKIES ANTICIPATED MOST AREAS FOR THIS AFTERNOON. EVEN IF THE SUN
IS OUT...IT WON/T DO A WHOLE LOT TO MASK WHAT IS ALMOST CERTAINLY
TO BE THE OVERALL COLDEST DAY OF THE WINTER SO FAR FOR MOST OF THE
CWA. AS THE DAY WEARS ON...THE CENTER OF THE SURFACE HIGH WILL
MIGRATE INTO MN/IA...ALLOWING BREEZES TO GRADUALLY DIMINISH INTO
THE 5-10 MPH RANGE FOR THIS AFTERNOON AS THEY GRADUALLY SHIFT FROM
MORE NORTHERLY TO MORE EASTERLY/SOUTHEASTERLY BY LATE IN THE DAY.
AS FOR TEMPS...YET AGAIN OPTED TO LOWER HIGHS BY 2-5 DEGREES FROM
PREVIOUS FORECAST IN MOST AREAS...LEANING TOWARD THE COLDER MAV
GUIDANCE. THIS YIELDS HIGHS RANGING FROM ONLY 10-13 DEGREES IN THE
NORTHEAST CWA...TO MID 20S FAR SOUTH AND WEST WHERE THE SOUTHEAST
FLOW AROUND THE HIGH SHOULD HELP MODERATE THINGS SOMEWHAT. AS FOR
WIND CHILLS THIS MORNING...VALUES WILL CONTINUE TO RANGE BETWEEN
-10 AND -17 ACROSS MUCH OF THE NORTHEAST 1/2 OF THE CWA THROUGH AT
LEAST MID-MORNING...WHICH WILL BE ABOVE ADVISORY CRITERIA OF -20
BUT NOT BY MUCH. ITS CLOSE ENOUGH THAT WILL PUT A MENTION IN THE
HAZARDOUS WEATHER OUTLOOK.
TONIGHT...THE NEXT BATCH OF BROAD...LOW AMPLITUDE SHORTWAVE ENERGY
QUICKLY APPROACHES THE CENTRAL CONUS FROM THE NORTHWEST. WITHIN
THE ENTRANCE REGION OF THE PRIMARY UPPER JET AXIS MIGRATING ACROSS
THE UPPER MISS VALLEY/GREAT LAKES...AN IMPRESSIVE ZONE OF
ISENTROPIC LIFT/MID LEVEL CONVERGENCE WILL SET UP ALONG AND NORTH OF
THE PRIMARY LOW-MID LEVEL TEMPERATURE GRADIENT CENTERED FROM SD
INTO NORTHEAST NEB/IA. THIS WILL BE THE OBVIOUS FOCUS FOR THE
START OF A MEASURABLE SNOW EVENT FOR THOSE AREAS. ALTHOUGH IT IS
SEEMING MORE AND MORE LIKELY THAT THE CWA WILL MISS OUT ON THIS
ACTION...PREVIOUS FORECAST HAD SOME LOW POPS ACROSS THE
NORTHEAST...AND WILL CONTINUE THIS MENTION AFTER MIDNIGHT FOR
MAINLY THE NORTHEAST 1/5 OF THE CWA JUST IN CASE THE FAR SOUTHERN
EDGE OF THIS ACTIVITY SLIPS IN. ANY ACCUMULATIONS...IF ANY...WOULD
NOT AMOUNT TO MORE THAN A FEW TENTHS. INTERESTINGLY...IF ANYTHING
DOES HAPPEN TO FALL IN THE FAR NORTH TONIGHT...IT MIGHT ACTUALLY
FAVOR THE FORM OF LIGHT SLEET BASED ON FORECAST SOUNDINGS...BUT
WILL LEAVE IT AS SNOW MENTION FOR NOW. HAVE ALSO BEEN GROWING A
BIT LEARY OF POSSIBLE LIGHT FREEZING DRIZZLE ACROSS NORTHERN
PORTIONS OF THE AREA GIVEN THE GOOD LOW LEVEL WARM ADVECTION...BUT
THINKING AT THIS POINT IS THAT ANY POTENTIAL STRATUS LAYER WOULD
BE TOO SHALLOW TO SUPPORT THIS. SOMETHING TO WATCH. AS FOR LOW
TEMPS...CHANGED THEM LITTLE...ALTHOUGH CONFIDENCE IN HOURLY TRENDS
IS QUITE LOW AS TEMPS COULD EASILY DISPLAY STEADY/SLOWLY RISING
CHARACTERISTICS AS BREEZES TURN SOUTHERLY. KEPT IT SIMPLE FOR NOW
THOUGH...INDICATING MOST AREAS BOTTOMING OUT BETWEEN 9 AND 15
DEGREES...ALTHOUGH THIS MIGHT END UP BEING EARLIER IN THE NIGHT
VERSUS LATER FOR SOME PLACES.
FRIDAY...THE MAIN BATCH OF SHORTWAVE ENERGY PASSES THROUGH THE
CENTRAL PLAINS...ALTHOUGH THE UPPER JET FORCING CONTINUES TO
DIRECT THE MAIN PRECIP EVENT FROM EASTERN SD INTO NORTHERN
IA/SOUTHERN MN AND POINTS EAST. THUS LEFT PRECIP MENTION OUT OF
THE FORECAST...ALTHOUGH ONCE AGAIN WILL HAVE TO MONITOR DEPTH OF
POSSIBLE STRATUS LAYER CLOSELY FOR OUTSIDE CHANCE OF SNEAKY LIGHT
FREEZING DRIZZLE THREAT...BUT JUST SEEMS RATHER UNLIKELY AT THIS
JUNCTURE. AS FOR HIGH TEMPS...THE SOUTHERN EDGE OF THE ARCTIC COLD
FRONT WILL PLAY A BIG ROLE AS IT IS PROGGED TO DROP RIGHT BACK
SOUTH ACROSS THE CWA OVER THE COURSE OF THE DAY...ALTHOUGH THE GFS
IS MUCH MORE AGGRESSIVE THAN THE LATEST ECMWF/NAM REGARDING WITH
THIS COLD PUSH. CONSENSUS OF SEVERAL MODELS/GUIDANCE WAS TO...YOU
GUESSED IT...LOWER TEMPS SEVERAL DEGREES...AND BUMPED DOWN 3-5
DEGREES MOST AREAS...NOW ADVERTISING MID 20S NORTHEAST TO UPPER
30S SOUTHWEST. INTERESTING TO NOTE THAT THIS DAY HAS NOW TRENDED
15+ DEGREES COLDER THAN FORECASTS ISSUED JUST 2-3 DAYS AGO.
FRIDAY NIGHT...IT REMAINS DRY AS A SURFACE RIDGE AXIS SLIDES
ACROSS THE CENTRAL PLAINS...AND A BRIEF BIT OF SHORTWAVE RIDGING
SETS IN ALOFT. ASSUMING LIMITED CLOUD COVER...TEMPS COULD TAKE A
DECENT TUMBLE...AND LOWERED LOWS 5 DEGREES MOST AREAS WITH SINGLE
DIGITS ABOVE ZERO NOW IN PLACE FOR MUCH OF THE CWA.
SATURDAY...THE NEXT...MORE VIGOROUS MID LEVEL WAVE STARTS MAKING
ITS WAY ACROSS THE CENTRAL/SOUTHERN ROCKIES...INDUCING SURFACE
PRESSURE FALLS AND RAMPING UP SOUTH-SOUTHEAST BREEZES INTO AT
LEAST THE 15-20 MPH SUSTAINED RANGE. DESPITE THIS SOUTHERLY
WIND...THE DIRECTION IS NOT OVERLY CONDUCIVE FOR SIGNIFICANT
WARMING...AND HAVE ONLY INDICATED A MODEST WARM-UP OVER
FRIDAY...WITH HIGHS RANGING FROM LOW 30S FAR EAST TO LOW 40S FAR
WEST.
SATURDAY NIGHT...LEFT THIS PERIOD DRY...AT LEAST FOR NOW...AS THE
INCOMING SHORTWAVE CONTINUES TO AMPLIFY/STRENGTHEN AS A 100+KT
UPPER JET STARTS TO ROUND THE BASE INTO THE CENTRAL PLAINS. ONLY
THING KEEPING POPS FROM BEING INSERTED AT THIS POINT IS SUGGESTION
THAT A MID LEVEL DRY SLOT WILL BE IN PLACE ACROSS THE CWA...WITH
MAIN FORCING/MID LEVEL DEFORMATION AXIS HOLDING JUST OFF TO THE
NORTH/WEST...THUS HOLDING OFF BETTER PRECIP CHANCES UNTIL SUNDAY
AS DISCUSSED BELOW.
LONG TERM...SUNDAY THROUGH WEDNESDAY. PATTERN REMAINS
PROGRESSIVE THROUGH THE EXTENDED PERIODS WITH CHALLENGE OF TRYING
TO TIME WAVES. BEGINNING ON SUNDAY...A 100+KT JET NOSES EAST FM
THE FOUR CORNERS REGION AND LIFTS NORTHEAST ACROSS THE CENTRAL
PLAINS DEEPENING THE MID/UPPER TROUGH ACROSS THE CENTRAL PLAINS.
THE 00Z ECMWF IS THE STRONGEST/SLOWEST WITH THE SYSTEM ON SUNDAY
AND CLOSES OFF THE H7 LOW...WHEREAS OTHER EXTENDED MODELS SUGGEST
A MORE PROGRESSIVE OPEN WAVE. IN GENERAL...THERE IS CONSENSUS
AMONG MODELS THAT OUR REGION WILL BE UNDER THE INFLUENCE OF A
TROUGH THRU AT LEAST THE FIRST HALF OF THE DAY...OR LONGER IF
SLOWER ECWMF VERIFIES. COOL FRONTAL BOUNDARY WILL SWEEP ACROSS OUR
REGION IN MORNING WITH AN AREA OF LOW CLOUDS/PCPN ACCOMPANYING
SYSTEM AIDED BY ENHANCED UPPER DYNAMICS IN LFQ OF JET. HOW LONG
PCPN/LOW CLOUDS LINGERS IS DEPENDENT ON STRENGTH OF SYSTEM AND IF
SYSTEM MOVES THRU FASTER...CLEARING SKIES/DOWNSLOPE CONDITIONS MAY
AID IN SOME WARMING FOR THE AFTN. IN ADDITION TO THE PCPN
POTENTIAL...MODELS ALSO SUGGEST STRONG WIND POTENTIAL SUNDAY WITH
NAM INDICATING 3HR PRESSURE RISES OF 6MB BEHIND THE FRONT IN
TIGHTENING SFC GRADIENT...WHILE A CORRIDOR OF 50 TO 60KT MID
LEVEL WINDS CROSS OUR REGION. WILL NEED TO MONITOR MODEL TRENDS OF
THIS AS WELL. FOR PCPN TYPE ON SUNDAY...HAVE WENT WITH R/S IN THE
MORNING TRANSITIONING TO RAIN IN AFTN AS TEMPS LOOK TO RISE ABOVE
FREEZING.
HEADING INTO SUNDAY NIGHT...THE TROUGH AXIS DEPARTS AND CONDITIONS
DRY WITH RISING HEIGHTS BEHIND THE EXITING SYSTEM. MODELS ARE STILL
LOOKING DRY MONDAY IN BETWEEN SYSTEMS...AND THEN NEXT WAVE IS PROGGED
TO EMERGE ONTO THE PLAINS ON TUESDAY. THERE IS STILL SOME
UNCERTAINTY ON DEGREE OF MOISTURE WITH THIS NEXT SYSTEM BUT SMALL
CHCS FOR PCPN STILL WARRANTED AS CURRENTLY FORECAST. MILD AIRMASS IN PLACE
SHLD MAINTAIN LIQUID CHCS INITIALLY WITH POTENTIAL FOR CHANGE TO
SNOW IN COOLER AIR WITH FROPA TUESDAY NIGHT.
THE AIRMASS IN GENERAL DURING THE EXTENDED IS NOT OVERLY COLD AND
TEMPS LOOK TO BE MORE DEPENDENT ON CLOUDS/PCPN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
639 AM CST THU JAN 19 2012
.UPDATE...JUST RAN A QUICK UPDATE TO TABULAR AFM/PFM PRODUCTS AND
WEB-BASED PRODUCTS TO BRING NEXT SEVERAL HOURS OF TEMP/DEWPOINT
TRENDS MORE IN LINE WITH CURRENT OBS...AS COLDER AND DRIER AIR HAS
PUSHED MORE AGGRESSIVELY SOUTHWARD INTO SOUTHERN PORTIONS OF THE
CWA THAN EXPECTED EVEN A FEW HOURS AGO. ONLY MODEL/GUIDANCE REALLY
PROVING USEFUL FOR THESE VERY SHORT TERM TRENDS IS GFS LAMP
GUIDANCE. WIND CHILLS BETWEEN -10 AND -15 WILL BE WIDESPREAD
ACROSS MOST ALL NEB ZONES FOR THE NEXT FEW HOURS...WITH KS ZONES
MORE SO -5 TO -10. ALTHOUGH NO CHANGES WERE MADE TO AFTERNOON HIGH
TEMPS AT THIS TIME...INTERESTING TO NOTE THAT BOTH THE 09Z RUC AND
HRRR SUGGEST THAT THE TRI-CITIES WILL RECOVER ENOUGH TO POSSIBLY
REACH 20 THIS AFTERNOON...BUT THIS SEEMS TOO OPTIMISTIC AT THIS
TIME AND WILL STICK WITH GOING FORECAST.
&&
.PREV DISCUSSION... /ISSUED 600 AM CST THU JAN 19 2012/
AVIATION...12Z TAF. ARCTIC HIGH PRESSURE WILL SHIFT INTO NORTHERN
IOWA TODAY. NORTHEASTERLY WINDS THIS MORNING WILL BECOME VARIABLE
FOR A FEW HOURS AROUND MIDDAY BEFORE TRANSITIONING TO THE
SOUTHEAST. CLOUD COVER LOOKS TO BE LIMITED TO THE MID AND HIGH
LEVELS FOR MUCH OF THE DAY WITH SOME MVFR TO VFR CIGS POSSIBLE
LATER TONIGHT OR TOWARD FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 451 AM CST THU JAN 19 2012/
SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS CONTINUES TO BE TEMPERATURE TRENDS...WITH THE NEXT
REGIONAL SNOW EVENT FROM THURSDAY NIGHT INTO FRIDAY STILL PROGGED
TO MISS MOST...IF NOT ALL OF THE CWA TO THE NORTHEAST...FOCUSING
ALONG AN AXIS FROM SD THROUGH NORTHEAST NEB/NORTHERN IA. THAT
BEING SAID...ALTHOUGH NOT OVERLY CONCERNED AT THIS POINT...WILL
NEED TO MONITOR LOW LEVEL MOISTURE TRENDS CLOSELY LATE THURS NIGHT
INTO FRIDAY MORNING TO MAKE SURE THAT NO LIGHT FREEZING DRIZZLE
TRIES TO SNEAK UP ON US.
09Z OBJECTIVE SURFACE ANALYSIS REVEALS THAT THE WELL ADVERTISED
ARCTIC COLD FRONT HAS MADE STEADY PROGRESS SOUTHWARD ACROSS THE
CWA THROUGH THE NIGHT...PUSHED ALONG BY A BROAD 1024MB HIGH
CENTERED FROM MT TO NORTHERN SD. TEMPERATURES AT 09Z RANGED FROM 2
AT ORD...TO 18 AT BELOIT. ADDING TO THE INVADING BITTERNESS ARE
STEADY NORTH-NORTHEAST BREEZES OF 10-20 MPH...YIELDING WIND CHILL
VALUES RANGING FROM -10 TO -15 NORTH OF I-80...TO NEAR ZERO IN THE
SOUTH. DESPITE PLENTIFUL MID LEVEL RADAR RETURNS EARLIER THE NIGHT
ACROSS THE NORTHEAST...IT IS LIKELY THAT FLURRY ACTIVITY DID NOT
MATERIALIZE ACROSS THE NORTHEAST. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA FEATURE VERY FAST NORTHWEST FLOW BISECTING
THE CONUS FROM NORTHWEST TO SOUTHEAST...HIGHLIGHTED BY A 140+KT
300MB JET STREAK CUTTING ACROSS EASTERN NEB. ALTHOUGH THE PRIMARY
MID LEVEL SHORTWAVE/500MB VORT MAX OF NOTE IS ALREADY WELL
NORTHEAST INTO THE GREAT LAKES...LIFT ASSOCIATED WITH THE UPPER
JET STREAK HAS GENERATED PLENTIFUL CIRRUS OVER MAINLY NEB ZONES
OVERNIGHT...BUT KEEPING PRIMARY ZONE OF MID LEVEL
SATURATION/POSSIBLE LIGHT SNOW PRODUCTION OFF TO THE NORTH AND
EAST.
TODAY...THE AFOREMENTIONED STRONG UPPER JET AXIS DRIFTS
NORTHEAST...WITH ITS CENTER ALONG AN AXIS FROM CENTRAL ND TO
NORTHERN IL BY 00Z THIS EVENING. AS A RESULT...THE EXTENSIVE HIGH
LEVEL CLOUD COVER ACROSS MOST OF THE CWA SHOULD GRADUALLY SCATTER
OUT AND/OR LIFT NORTHEAST AS WELL...WITH AT LEAST PARTLY CLOUDY
SKIES ANTICIPATED MOST AREAS FOR THIS AFTERNOON. EVEN IF THE SUN
IS OUT...IT WON/T DO A WHOLE LOT TO MASK WHAT IS ALMOST CERTAINLY
TO BE THE OVERALL COLDEST DAY OF THE WINTER SO FAR FOR MOST OF THE
CWA. AS THE DAY WEARS ON...THE CENTER OF THE SURFACE HIGH WILL
MIGRATE INTO MN/IA...ALLOWING BREEZES TO GRADUALLY DIMINISH INTO
THE 5-10 MPH RANGE FOR THIS AFTERNOON AS THEY GRADUALLY SHIFT FROM
MORE NORTHERLY TO MORE EASTERLY/SOUTHEASTERLY BY LATE IN THE DAY.
AS FOR TEMPS...YET AGAIN OPTED TO LOWER HIGHS BY 2-5 DEGREES FROM
PREVIOUS FORECAST IN MOST AREAS...LEANING TOWARD THE COLDER MAV
GUIDANCE. THIS YIELDS HIGHS RANGING FROM ONLY 10-13 DEGREES IN THE
NORTHEAST CWA...TO MID 20S FAR SOUTH AND WEST WHERE THE SOUTHEAST
FLOW AROUND THE HIGH SHOULD HELP MODERATE THINGS SOMEWHAT. AS FOR
WIND CHILLS THIS MORNING...VALUES WILL CONTINUE TO RANGE BETWEEN
-10 AND -17 ACROSS MUCH OF THE NORTHEAST 1/2 OF THE CWA THROUGH AT
LEAST MID-MORNING...WHICH WILL BE ABOVE ADVISORY CRITERIA OF -20
BUT NOT BY MUCH. ITS CLOSE ENOUGH THAT WILL PUT A MENTION IN THE
HAZARDOUS WEATHER OUTLOOK.
TONIGHT...THE NEXT BATCH OF BROAD...LOW AMPLITUDE SHORTWAVE ENERGY
QUICKLY APPROACHES THE CENTRAL CONUS FROM THE NORTHWEST. WITHIN
THE ENTRANCE REGION OF THE PRIMARY UPPER JET AXIS MIGRATING ACROSS
THE UPPER MISS VALLEY/GREAT LAKES...AN IMPRESSIVE ZONE OF
ISENTROPIC LIFT/MID LEVEL CONVERGENCE WILL SET UP ALONG AND NORTH OF
THE PRIMARY LOW-MID LEVEL TEMPERATURE GRADIENT CENTERED FROM SD
INTO NORTHEAST NEB/IA. THIS WILL BE THE OBVIOUS FOCUS FOR THE
START OF A MEASURABLE SNOW EVENT FOR THOSE AREAS. ALTHOUGH IT IS
SEEMING MORE AND MORE LIKELY THAT THE CWA WILL MISS OUT ON THIS
ACTION...PREVIOUS FORECAST HAD SOME LOW POPS ACROSS THE
NORTHEAST...AND WILL CONTINUE THIS MENTION AFTER MIDNIGHT FOR
MAINLY THE NORTHEAST 1/5 OF THE CWA JUST IN CASE THE FAR SOUTHERN
EDGE OF THIS ACTIVITY SLIPS IN. ANY ACCUMULATIONS...IF ANY...WOULD
NOT AMOUNT TO MORE THAN A FEW TENTHS. INTERESTINGLY...IF ANYTHING
DOES HAPPEN TO FALL IN THE FAR NORTH TONIGHT...IT MIGHT ACTUALLY
FAVOR THE FORM OF LIGHT SLEET BASED ON FORECAST SOUNDINGS...BUT
WILL LEAVE IT AS SNOW MENTION FOR NOW. HAVE ALSO BEEN GROWING A
BIT LEARY OF POSSIBLE LIGHT FREEZING DRIZZLE ACROSS NORTHERN
PORTIONS OF THE AREA GIVEN THE GOOD LOW LEVEL WARM ADVECTION...BUT
THINKING AT THIS POINT IS THAT ANY POTENTIAL STRATUS LAYER WOULD
BE TOO SHALLOW TO SUPPORT THIS. SOMETHING TO WATCH. AS FOR LOW
TEMPS...CHANGED THEM LITTLE...ALTHOUGH CONFIDENCE IN HOURLY TRENDS
IS QUITE LOW AS TEMPS COULD EASILY DISPLAY STEADY/SLOWLY RISING
CHARACTERISTICS AS BREEZES TURN SOUTHERLY. KEPT IT SIMPLE FOR NOW
THOUGH...INDICATING MOST AREAS BOTTOMING OUT BETWEEN 9 AND 15
DEGREES...ALTHOUGH THIS MIGHT END UP BEING EARLIER IN THE NIGHT
VERSUS LATER FOR SOME PLACES.
FRIDAY...THE MAIN BATCH OF SHORTWAVE ENERGY PASSES THROUGH THE
CENTRAL PLAINS...ALTHOUGH THE UPPER JET FORCING CONTINUES TO
DIRECT THE MAIN PRECIP EVENT FROM EASTERN SD INTO NORTHERN
IA/SOUTHERN MN AND POINTS EAST. THUS LEFT PRECIP MENTION OUT OF
THE FORECAST...ALTHOUGH ONCE AGAIN WILL HAVE TO MONITOR DEPTH OF
POSSIBLE STRATUS LAYER CLOSELY FOR OUTSIDE CHANCE OF SNEAKY LIGHT
FREEZING DRIZZLE THREAT...BUT JUST SEEMS RATHER UNLIKELY AT THIS
JUNCTURE. AS FOR HIGH TEMPS...THE SOUTHERN EDGE OF THE ARCTIC COLD
FRONT WILL PLAY A BIG ROLE AS IT IS PROGGED TO DROP RIGHT BACK
SOUTH ACROSS THE CWA OVER THE COURSE OF THE DAY...ALTHOUGH THE GFS
IS MUCH MORE AGGRESSIVE THAN THE LATEST ECMWF/NAM REGARDING WITH
THIS COLD PUSH. CONSENSUS OF SEVERAL MODELS/GUIDANCE WAS TO...YOU
GUESSED IT...LOWER TEMPS SEVERAL DEGREES...AND BUMPED DOWN 3-5
DEGREES MOST AREAS...NOW ADVERTISING MID 20S NORTHEAST TO UPPER
30S SOUTHWEST. INTERESTING TO NOTE THAT THIS DAY HAS NOW TRENDED
15+ DEGREES COLDER THAN FORECASTS ISSUED JUST 2-3 DAYS AGO.
FRIDAY NIGHT...IT REMAINS DRY AS A SURFACE RIDGE AXIS SLIDES
ACROSS THE CENTRAL PLAINS...AND A BRIEF BIT OF SHORTWAVE RIDGING
SETS IN ALOFT. ASSUMING LIMITED CLOUD COVER...TEMPS COULD TAKE A
DECENT TUMBLE...AND LOWERED LOWS 5 DEGREES MOST AREAS WITH SINGLE
DIGITS ABOVE ZERO NOW IN PLACE FOR MUCH OF THE CWA.
SATURDAY...THE NEXT...MORE VIGOROUS MID LEVEL WAVE STARTS MAKING
ITS WAY ACROSS THE CENTRAL/SOUTHERN ROCKIES...INDUCING SURFACE
PRESSURE FALLS AND RAMPING UP SOUTH-SOUTHEAST BREEZES INTO AT
LEAST THE 15-20 MPH SUSTAINED RANGE. DESPITE THIS SOUTHERLY
WIND...THE DIRECTION IS NOT OVERLY CONDUCIVE FOR SIGNIFICANT
WARMING...AND HAVE ONLY INDICATED A MODEST WARM-UP OVER
FRIDAY...WITH HIGHS RANGING FROM LOW 30S FAR EAST TO LOW 40S FAR
WEST.
SATURDAY NIGHT...LEFT THIS PERIOD DRY...AT LEAST FOR NOW...AS THE
INCOMING SHORTWAVE CONTINUES TO AMPLIFY/STRENGTHEN AS A 100+KT
UPPER JET STARTS TO ROUND THE BASE INTO THE CENTRAL PLAINS. ONLY
THING KEEPING POPS FROM BEING INSERTED AT THIS POINT IS SUGGESTION
THAT A MID LEVEL DRY SLOT WILL BE IN PLACE ACROSS THE CWA...WITH
MAIN FORCING/MID LEVEL DEFORMATION AXIS HOLDING JUST OFF TO THE
NORTH/WEST...THUS HOLDING OFF BETTER PRECIP CHANCES UNTIL SUNDAY
AS DISCUSSED BELOW.
LONG TERM...SUNDAY THROUGH WEDNESDAY. PATTERN REMAINS
PROGRESSIVE THROUGH THE EXTENDED PERIODS WITH CHALLENGE OF TRYING
TO TIME WAVES. BEGINNING ON SUNDAY...A 100+KT JET NOSES EAST FM
THE FOUR CORNERS REGION AND LIFTS NORTHEAST ACROSS THE CENTRAL
PLAINS DEEPENING THE MID/UPPER TROUGH ACROSS THE CENTRAL PLAINS.
THE 00Z ECMWF IS THE STRONGEST/SLOWEST WITH THE SYSTEM ON SUNDAY
AND CLOSES OFF THE H7 LOW...WHEREAS OTHER EXTENDED MODELS SUGGEST
A MORE PROGRESSIVE OPEN WAVE. IN GENERAL...THERE IS CONSENSUS
AMONG MODELS THAT OUR REGION WILL BE UNDER THE INFLUENCE OF A
TROUGH THRU AT LEAST THE FIRST HALF OF THE DAY...OR LONGER IF
SLOWER ECWMF VERIFIES. COOL FRONTAL BOUNDARY WILL SWEEP ACROSS OUR
REGION IN MORNING WITH AN AREA OF LOW CLOUDS/PCPN ACCOMPANYING
SYSTEM AIDED BY ENHANCED UPPER DYNAMICS IN LFQ OF JET. HOW LONG
PCPN/LOW CLOUDS LINGERS IS DEPENDENT ON STRENGTH OF SYSTEM AND IF
SYSTEM MOVES THRU FASTER...CLEARING SKIES/DOWNSLOPE CONDITIONS MAY
AID IN SOME WARMING FOR THE AFTN. IN ADDITION TO THE PCPN
POTENTIAL...MODELS ALSO SUGGEST STRONG WIND POTENTIAL SUNDAY WITH
NAM INDICATING 3HR PRESSURE RISES OF 6MB BEHIND THE FRONT IN
TIGHTENING SFC GRADIENT...WHILE A CORRIDOR OF 50 TO 60KT MID
LEVEL WINDS CROSS OUR REGION. WILL NEED TO MONITOR MODEL TRENDS OF
THIS AS WELL. FOR PCPN TYPE ON SUNDAY...HAVE WENT WITH R/S IN THE
MORNING TRANSITIONING TO RAIN IN AFTN AS TEMPS LOOK TO RISE ABOVE
FREEZING.
HEADING INTO SUNDAY NIGHT...THE TROUGH AXIS DEPARTS AND CONDITIONS
DRY WITH RISING HEIGHTS BEHIND THE EXITING SYSTEM. MODELS ARE STILL
LOOKING DRY MONDAY IN BETWEEN SYSTEMS...AND THEN NEXT WAVE IS PROGGED
TO EMERGE ONTO THE PLAINS ON TUESDAY. THERE IS STILL SOME
UNCERTAINTY ON DEGREE OF MOISTURE WITH THIS NEXT SYSTEM BUT SMALL
CHCS FOR PCPN STILL WARRANTED AS CURRENTLY FORECAST. MILD AIRMASS IN PLACE
SHLD MAINTAIN LIQUID CHCS INITIALLY WITH POTENTIAL FOR CHANGE TO
SNOW IN COOLER AIR WITH FROPA TUESDAY NIGHT.
THE AIRMASS IN GENERAL DURING THE EXTENDED IS NOT OVERLY COLD AND
TEMPS LOOK TO BE MORE DEPENDENT ON CLOUDS/PCPN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...CF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
310 PM EST THU JAN 19 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC. THIS STORM WILL BRING MODERATE SNOW TO
THE SOUTHERN TIER OF NY, CATSKILLS, AND NORTHEASTERN PA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HGTS BLD SUN NGT WITH MID AND LL WAA AHD OF A WRN LAKES LOW. LGT
PCPN SEEM PSBL WITH MUCH UNCERTAINTY ABT THE TEMP PROFILE. MIXED
PCPN SEEMS LIKELY WITH SFC TEMPS NEAR OR BLO FRZG...SO SOME FRZG
RAIN PSBL. LOW MVES SLWLY EAST AS AN OCCLUDED FNT RACES EWRD THRU
THE OH VLY AND WRN NY. TIMING PUSHES THE FNT THRU THE AREA MON
EVE...BUT WITH MODIFIED COLD AIR PUSHING IN FROM THE SW...DO NOT
XPCT A DRAMATIC TEMP DROP LATE MON INTO TUE. UPR LOW LIFTS NORTH
TUE AS THE TROF AXIS PASSES. AIR IS JUST NOT THAT COLD WITH H8
TEMPS FCSTD IN THE -6C TO -8C RANGE. XPCT SOME MOISTURE WITH THE
UPR TROF AND SOME MRGNL LE SNOW SHWRS INTO WED. LATE WED A SFC HI
OVER THE OH VLY BLDS IN BUT WITH ZONAL FLOW OVER THE FCST
AREA...TEMPS RATHER NEUTRAL AND WITH A WEAK SFC TROF AND APRCHG
WC...JUST SOME LGT PCPN IN THE AREA FOR THE END OF THE PD.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
COLD FNT WILL PASS THRU THE AREA ARND 00Z BRINGING SNOW SHWRS AND
MVFR/IFR CONDS. PCPN SHD BE BRIEF INVOF THE FNT...HWVR...CAA BHD
THE FNT WILL TRIGGER LE SNOWS AND PROLONGED LWR CONDS AT RME. AS
THE FLOW BECOMES MORE NWLY...LE WILL BREAK AWAY FROM THE ALKE AND
BRING SOME OCNL MVFR CONDS TO STATIONS IN CNTRL NY THRU THE END OF
THE PD. GUSTY SLY WINDS AHD OF THE FNT WILL BECOME WLY AND GUSTY
BHD THE FNT EARLY THIS EVE.
.OUTLOOK...
FRI AFTN...MVFR BECOMING VFR AS LE SNOW WINDS DOWN.
SAT...MVFR/IFR IN SNOW.
SUN...MAINLY VFR.
MON..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 11 AM EST FRIDAY FOR NYZ018-036-
037.
WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP
SHORT TERM...DJP
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
254 PM EST THU JAN 19 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC. THIS STORM WILL BRING MODERATE SNOW TO
THE SOUTHERN TIER OF NY, CATSKILLS, AND NORTHEASTERN PA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
PATTERN OF A GENERAL SOUTHWEST FLOW WITH OCCASIONAL WAVES...WILL ALTERNATE
US ON EITHER SIDE OF THE 540 DECAMETER LINE IN REGARDS TO
1000-500MB THICKNESS. REGARDLESS OF PRECIPITATION TYPE DURING THE
PERIOD...IT WILL BE A WARMER THAN NORMAL PATTERN FOR LATE
JANUARY...A THEME THAT HAS DOMINATED MOST OF THIS WINTER SO FAR.
WE BEGIN SATURDAY NIGHT THROUGH SUNDAY MORNING...BETWEEN WAVES
WITH SEASONABLY COLD LOWS AND MAINLY DRY WEATHER. AN EXTENSION OF
A SOUTHERN STREAM UPPER WAVE MAY SKIM US LATE SUNDAY INTO MONDAY
MORNING. IF PRECIPITATION MANAGES TO REACH US...GENERAL SET UP AND
GFS MODEL SOUNDINGS SUGGEST THERE IS SOME PROSPECT FOR A LIGHT
WINTRY MIX INITIALLY BEFORE PLAIN RAIN. GFS/ECWMF AGREE BETTER
THOUGH...ON A NORTHERN STREAM TROUGH THEN SWINGING THROUGH LATE
MONDAY OR MONDAY NIGHT. THE COLD AIR BEHIND THAT SYSTEM LOOKS
PRETTY MEAGER...SO UNLESS BETTER PENETRATION OF COLDER AIR
OCCURS...THE RESULTING LAKE RESPONSE ON TUESDAY ALSO LOOKS
MEDIOCRE. WE MAY END UP JUST HAVING SCATTERED SNOW SHOWERS SIMPLY
FROM SYNOPTIC WRAP AROUND/COMMA HEAD OF SYSTEM...WITH NOT A WHOLE
LOT OF ASSISTANCE FROM THE LAKES. THE DOMINANT SOUTHWEST FLOW
QUICKLY BRINGS IN WARMER AIR AND SURFACE HIGH PRESSURE INTO
WEDNESDAY...AND TEMPERATURES LOOK TO BE ROUGHLY 10 DEGREES ABOVE
NORMAL AT THAT TIME. NORTH ATLANTIC OSCILLATION INDEX IS POSITIVE
NOW...AND IS FORECAST TO REMAIN POSITIVE THIS WEEK...SUPPORTING
THE WARMER THAN NORMAL PATTERN.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
COLD FNT WILL PASS THRU THE AREA ARND 00Z BRINGING SNOW SHWRS AND
MVFR/IFR CONDS. PCPN SHD BE BRIEF INVOF THE FNT...HWVR...CAA BHD
THE FNT WILL TRIGGER LE SNOWS AND PROLONGED LWR CONDS AT RME. AS
THE FLOW BECOMES MORE NWLY...LE WILL BREAK AWAY FROM THE ALKE AND
BRING SOME OCNL MVFR CONDS TO STATIONS IN CNTRL NY THRU THE END OF
THE PD. GUSTY SLY WINDS AHD OF THE FNT WILL BECOME WLY AND GUSTY
BHD THE FNT EARLY THIS EVE.
.OUTLOOK...
FRI AFTN...MVFR BECOMING VFR AS LE SNOW WINDS DOWN.
SAT...MVFR/IFR IN SNOW.
SUN...MAINLY VFR.
MON..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 11 AM EST
FRIDAY FOR NYZ018-036-037.
WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP
SHORT TERM...DJP
LONG TERM...MDP
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1240 PM EST THU JAN 19 2012
.SYNOPSIS...
MUCH OF TODAY WILL FEATURE DRY WEATHER...AND SEASONABLY CHILLY
TEMPERATURES. A COLD FRONT WILL CROSS THE AREA THIS EVENING...ACCOMPANIED
BY SNOW SHOWERS...AND A FEW SQUALLS. BEHIND THE FRONT...A BRIEF
PERIOD OF LAKE EFFECT SNOW SHOULD IMPACT UPSTATE NEW YORK LATE
TONIGHT AND EARLY FRIDAY...BEFORE DIMINISHING IN THE AFTERNOON. A
FAST MOVING STORM SYSTEM SHOULD TRACK INTO THE MID-ATLANTIC STATES
BY SATURDAY...PERHAPS BRINGING A PERIOD OF SNOW OR MIXED
PRECIPITATION TO START THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM UPDATE...LATEST HRRR REFLECTIVITY SUGGESTS IF THERE IS A
SQUALL, IT WILL ARRIVE WELL AFTER SUNSET. WE WILL CONTINUE TO
WATCH THE MESOSCALE MODEL TRENDS AND THE OBS/SAT FOR CLUES AS TO
TIMING AND INTENSITY OF SNOW SHOWERS.
CURRENT GRIDS HAVE BEEN TWEAKED FOR TEMPS. OTHERWISE THE FORECAST
LOOKS TO BE IN GOOD SHAPE.
7 AM UPDATE... JUST MINOR TWEAKS TO TEMP/SKY GRIDS.
INITIAL BAND OF HIGH-LVL CLDS IS ERODING ATTM...SO WE ADJUSTED TO
GO FOR A SUNNIER AM PD...BEFORE THICKER CLDS COME IN FROM THE W
TWDS MIDDAY.
OTHWS...NO SIG CHANGES.
PREV DISC... 5 AM UPDATE...ALL IS QUIET EARLY THIS MRNG...AND
SHOULD REMAIN SO FOR MUCH OF THE DAY...WITH JUST AN INCREASE IN
MAINLY MID AND HIGH-LVL CLDS FROM MIDDAY ON. TEMPS SHOULD REBOUND
INTO THE UPPER 20S OR LOWER 30S FOR MANY LOCALES THIS AFTN...WITH
A FAIRLY ROBUST SRLY FLOW DVLPG (HILLTOP SXNS GUSTING TO NEAR 30
MPH AFTER 18Z).
A SHARP COLD FRNT WAS CROSSING CNTRL MI AND THE CHICAGO AREA JUST
PRIOR TO SUNRISE. THE FRNT WAS MAKING STEADY EWD PROGRESS...AND
ALL NEAR-TERM GUIDANCE IS IN AGREEMENT THAT THIS SYSTEM WILL STRETCH
ACRS WRN NY BY 21Z. AS MOIST AND FORCING BEGIN TO INCREASE IN
ADVANCE OF THIS SYSTEM...SCTD SHSN AND FLRYS SHOULD DEVELOP IN OUR
NRN/WRN ZNS BY LATE IN THE DAY...SPCLY THE SRN TUG HILL
RGN...WHERE SRLY UPSLOPE FLOW WILL BE WELL ESTABLISHED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
530 AM UPDATE... THE ABV MENTIONED COLD FRNT WILL CROSS THE FA
THIS EVE...GENERALLY IN THE 00-04Z TIME FRAME...LIKELY ACCOMPANIED
BY A FEW SQUALLS...SPCLY N AND W OF KBGM. ALTHOUGH LOW-LVL LR`S
SEEM TO BE A BIT SHORT OF WHAT WE`D NORMALLY SEE IN A FRNTL
SQUALL/WINDEX SITN...THEY ARE STILL IN THE 7-8C/KM RANGE IN THE
LOWEST 3 KM AGL. THE SUPPORTING UPPER-LVL TROUGH IS ALSO FAIRLY
DYNAMIC IN NATURE...AND GOOD LOW-LVL CAA FOLLOWS BEHIND THE SFC
FRNT. THUS...WE FEEL SOME AREAS WILL SEE A QUICK INCH OR SO OF
ACCUM THIS EVE...MOSTLY CNY.
AFTER A 3-5 HOUR PERIOD OF MOSTLY DRY WX...OR PERHAPS A FEW FLRYS/-SHSN...
FOR THE LATE EVE/OVERNIGHT TIME FRAME...THE LES MACHINE SHOULD
KICK INTO GEAR E AND SE OF LK ONT IN THE PRE-DAWN HRS (06-09Z).
NWP AGREEMENT (NAM12/LOCAL WRF/GFS40) IS PRETTY GOOD THAT A SINGLE
BAND WILL FIRST IMPACT OSWEGO/LEWIS CNTYS...BEFORE DROPPING INTO
NRN ONEIDA BY 08-09Z. FOR A RELATIVELY SHORT PD EARLY FRI...A
MULTI-LK INFLUENCE WITH GEO BAY LOOKS PSBL...WHICH WOULD HELP TO
ENHANCE MOIST DEPTHS/DZ FAVORABILITY. DUE TO THE COMBO OF 1-3"
EARLIER THU EVE WITH THE FRNT...AND THEN AN ADDITIONAL SEVERAL
INCHES OF LAKE EFF ACCUM EARLY FRI...A WINTER WX ADVSY HAS BEEN
POSTED FOR NRN ONEIDA.
PRESENT INDICATIONS ARE THAT THE MAIN LES BAND WILL GRADUALLY
WEAKEN AFTER 12Z FRI...AS IT DROPS SWD THROUGH
ONONDAGA/MADISON/SRN ONEIDA CNTYS...AND INTO
CORTLAND/CHENANGO/OTSEGO CNTYS. A LOWERING INVERSION...COMPROMISED
DENDRITE PRODUCTION...AND INCREASED DIR SHEAR...SHOULD ALL TAKE
THEIR TOLL...LIKELY CAUSING ACCUMS TO DROP OFF WITH TIME. OUR SRN
ZNS SHOULD ONLY SEE A FEW FLRYS AT WORST...WITH PROBABLE BREAKS OF
SUNSHINE BY AFTN.
AFTER A BRIEF LULL EARLY FRI EVE...THE NEXT SYNOPTIC SYSTEM IS
SLATED TO QUICKLY ARRIVE. MODEL EVOLUTION IS ALL PRETTY SIMILAR AT
THIS PT...TAKING A FAST MOVING SFC WAVE FROM THE OH/TN VLYS LATE
FRI NGT...TO THE DELMARVA RGN ON SAT. ALTHOUGH A STG WAA PATN
BECOMES ESTABLISHED THIS PD ACRS NE PA/CNY...ALG WITH A DEEPENING
MOIST SUPPLY...THE MAIN UPPER-LVL WAVE IS RATHER FLAT AND FAST
MOVG...AND THIS RAPID SYSTEM MOVEMENT COULD WELL KEEP PCPN AMTS
DOWN. MY GUT FEELING IS THAT MODEL QPF`S OF 0.3-0.5" LIQUID ARE A
BIT OVERDONE...BUT EVEN IF THEY ARE...SEVERAL INCHES OF SNOW ARE
STILL PSBL. WE`LL ALSO HAVE TO WATCH FOR THE PSBLTY THAT AN
ELEVATED WARM LYR BECOMES INCORPORATED...WHICH COULD POTENTIALLY
CREATE A WINTRY MIX SITN FOR PTNS OF THE FA. WE`LL BE MONITORING
THIS SYSTEM CLOSELY OVER THE NEXT COUPLE OF DAYS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
PATTERN OF A GENERAL SOUTHWEST FLOW WITH OCCASIONAL WAVES...WILL
ALTERNATE US ON EITHER SIDE OF THE 540 DECAMETER LINE IN REGARDS
TO 1000-500MB THICKNESS. REGARDLESS OF PRECIPITATION TYPE DURING
THE PERIOD...IT WILL BE A WARMER THAN NORMAL PATTERN FOR LATE
JANUARY...A THEME THAT HAS DOMINATED MOST OF THIS WINTER SO FAR.
WE BEGIN SATURDAY NIGHT THROUGH SUNDAY MORNING...BETWEEN WAVES
WITH SEASONABLY COLD LOWS AND MAINLY DRY WEATHER. AN EXTENSION OF
A SOUTHERN STREAM UPPER WAVE MAY SKIM US LATE SUNDAY INTO MONDAY
MORNING. IF PRECIPITATION MANAGES TO REACH US...GENERAL SET UP AND
GFS MODEL SOUNDINGS SUGGEST THERE IS SOME PROSPECT FOR A LIGHT
WINTRY MIX INITIALLY BEFORE PLAIN RAIN. GFS/ECWMF AGREE BETTER
THOUGH...ON A NORTHERN STREAM TROUGH THEN SWINGING THROUGH LATE
MONDAY OR MONDAY NIGHT. THE COLD AIR BEHIND THAT SYSTEM LOOKS
PRETTY MEAGER...SO UNLESS BETTER PENETRATION OF COLDER AIR
OCCURS...THE RESULTING LAKE RESPONSE ON TUESDAY ALSO LOOKS
MEDIOCRE. WE MAY END UP JUST HAVING SCATTERED SNOW SHOWERS SIMPLY
FROM SYNOPTIC WRAP AROUND/COMMA HEAD OF SYSTEM...WITH NOT A WHOLE
LOT OF ASSISTANCE FROM THE LAKES. THE DOMINANT SOUTHWEST FLOW
QUICKLY BRINGS IN WARMER AIR AND SURFACE HIGH PRESSURE INTO
WEDNESDAY...AND TEMPERATURES LOOK TO BE ROUGHLY 10 DEGREES ABOVE
NORMAL AT THAT TIME. NORTH ATLANTIC OSCILLATION INDEX IS POSITIVE
NOW...AND IS FORECAST TO REMAIN POSITIVE THIS WEEK...SUPPORTING
THE WARMER THAN NORMAL PATTERN.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
COLD FNT WILL PASS THRU THE AREA ARND 00Z BRINGING SNOW SHWRS AND
MVFR/IFR CONDS. PCPN SHD BE BRIEF INVOF THE FNT...HWVR...CAA BHD
THE FNT WILL TRIGGER LE SNOWS AND PROLONGED LWR CONDS AT RME. AS
THE FLOW BECOMES MORE NWLY...LE WILL BREAK AWAY FROM THE ALKE AND
BRING SOME OCNL MVFR CONDS TO STATIONS IN CNTRL NY THRU THE END OF
THE PD. GUSTY SLY WINDS AHD OF THE FNT WILL BECOME WLY AND GUSTY
BHD THE FNT EARLY THIS EVE.
.OUTLOOK...
FRI AFTN...MVFR BECOMING VFR AS LE SNOW WINDS DOWN.
SAT...MVFR/IFR IN SNOW.
SUN...MAINLY VFR.
MON..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 9 AM EST
FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...MDP
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
932 AM EST THU JAN 19 2012
.SYNOPSIS...
MUCH OF TODAY WILL FEATURE DRY WEATHER...AND SEASONABLY CHILLY
TEMPERATURES. A COLD FRONT WILL CROSS THE AREA THIS EVENING...ACCOMPANIED
BY SNOW SHOWERS...AND A FEW SQUALLS. BEHIND THE FRONT...A BRIEF
PERIOD OF LAKE EFFECT SNOW SHOULD IMPACT UPSTATE NEW YORK LATE
TONIGHT AND EARLY FRIDAY...BEFORE DIMINISHING IN THE AFTERNOON. A
FAST MOVING STORM SYSTEM SHOULD TRACK INTO THE MID-ATLANTIC STATES
BY SATURDAY...PERHAPS BRINGING A PERIOD OF SNOW OR MIXED
PRECIPITATION TO START THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM UPDATE...LATEST HRRR REFLECTIVITY SUGGESTS IF THERE IS A
SQUALL, IT WILL ARRIVE WELL AFTER SUNSET. WE WILL CONTINUE TO
WATCH THE MESOSCALE MODEL TRENDS AND THE OBS/SAT FOR CLUES AS TO
TIMING AND INTENSITY OF SNOW SHOWERS.
CURRENT GRIDS HAVE BEEN TWEAKED FOR TEMPS. OTHERWISE THE FORECAST
LOOKS TO BE IN GOOD SHAPE.
7 AM UPDATE... JUST MINOR TWEAKS TO TEMP/SKY GRIDS.
INITIAL BAND OF HIGH-LVL CLDS IS ERODING ATTM...SO WE ADJUSTED TO
GO FOR A SUNNIER AM PD...BEFORE THICKER CLDS COME IN FROM THE W
TWDS MIDDAY.
OTHWS...NO SIG CHANGES.
PREV DISC... 5 AM UPDATE...ALL IS QUIET EARLY THIS MRNG...AND
SHOULD REMAIN SO FOR MUCH OF THE DAY...WITH JUST AN INCREASE IN
MAINLY MID AND HIGH-LVL CLDS FROM MIDDAY ON. TEMPS SHOULD REBOUND
INTO THE UPPER 20S OR LOWER 30S FOR MANY LOCALES THIS AFTN...WITH
A FAIRLY ROBUST SRLY FLOW DVLPG (HILLTOP SXNS GUSTING TO NEAR 30
MPH AFTER 18Z).
A SHARP COLD FRNT WAS CROSSING CNTRL MI AND THE CHICAGO AREA JUST
PRIOR TO SUNRISE. THE FRNT WAS MAKING STEADY EWD PROGRESS...AND
ALL NEAR-TERM GUIDANCE IS IN AGREEMENT THAT THIS SYSTEM WILL STRETCH
ACRS WRN NY BY 21Z. AS MOIST AND FORCING BEGIN TO INCREASE IN
ADVANCE OF THIS SYSTEM...SCTD SHSN AND FLRYS SHOULD DEVELOP IN OUR
NRN/WRN ZNS BY LATE IN THE DAY...SPCLY THE SRN TUG HILL
RGN...WHERE SRLY UPSLOPE FLOW WILL BE WELL ESTABLISHED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
530 AM UPDATE... THE ABV MENTIONED COLD FRNT WILL CROSS THE FA
THIS EVE...GENERALLY IN THE 00-04Z TIME FRAME...LIKELY ACCOMPANIED
BY A FEW SQUALLS...SPCLY N AND W OF KBGM. ALTHOUGH LOW-LVL LR`S
SEEM TO BE A BIT SHORT OF WHAT WE`D NORMALLY SEE IN A FRNTL
SQUALL/WINDEX SITN...THEY ARE STILL IN THE 7-8C/KM RANGE IN THE
LOWEST 3 KM AGL. THE SUPPORTING UPPER-LVL TROUGH IS ALSO FAIRLY
DYNAMIC IN NATURE...AND GOOD LOW-LVL CAA FOLLOWS BEHIND THE SFC
FRNT. THUS...WE FEEL SOME AREAS WILL SEE A QUICK INCH OR SO OF
ACCUM THIS EVE...MOSTLY CNY.
AFTER A 3-5 HOUR PERIOD OF MOSTLY DRY WX...OR PERHAPS A FEW FLRYS/-SHSN...
FOR THE LATE EVE/OVERNIGHT TIME FRAME...THE LES MACHINE SHOULD
KICK INTO GEAR E AND SE OF LK ONT IN THE PRE-DAWN HRS (06-09Z).
NWP AGREEMENT (NAM12/LOCAL WRF/GFS40) IS PRETTY GOOD THAT A SINGLE
BAND WILL FIRST IMPACT OSWEGO/LEWIS CNTYS...BEFORE DROPPING INTO
NRN ONEIDA BY 08-09Z. FOR A RELATIVELY SHORT PD EARLY FRI...A
MULTI-LK INFLUENCE WITH GEO BAY LOOKS PSBL...WHICH WOULD HELP TO
ENHANCE MOIST DEPTHS/DZ FAVORABILITY. DUE TO THE COMBO OF 1-3"
EARLIER THU EVE WITH THE FRNT...AND THEN AN ADDITIONAL SEVERAL
INCHES OF LAKE EFF ACCUM EARLY FRI...A WINTER WX ADVSY HAS BEEN
POSTED FOR NRN ONEIDA.
PRESENT INDICATIONS ARE THAT THE MAIN LES BAND WILL GRADUALLY
WEAKEN AFTER 12Z FRI...AS IT DROPS SWD THROUGH
ONONDAGA/MADISON/SRN ONEIDA CNTYS...AND INTO
CORTLAND/CHENANGO/OTSEGO CNTYS. A LOWERING INVERSION...COMPROMISED
DENDRITE PRODUCTION...AND INCREASED DIR SHEAR...SHOULD ALL TAKE
THEIR TOLL...LIKELY CAUSING ACCUMS TO DROP OFF WITH TIME. OUR SRN
ZNS SHOULD ONLY SEE A FEW FLRYS AT WORST...WITH PROBABLE BREAKS OF
SUNSHINE BY AFTN.
AFTER A BRIEF LULL EARLY FRI EVE...THE NEXT SYNOPTIC SYSTEM IS
SLATED TO QUICKLY ARRIVE. MODEL EVOLUTION IS ALL PRETTY SIMILAR AT
THIS PT...TAKING A FAST MOVING SFC WAVE FROM THE OH/TN VLYS LATE
FRI NGT...TO THE DELMARVA RGN ON SAT. ALTHOUGH A STG WAA PATN
BECOMES ESTABLISHED THIS PD ACRS NE PA/CNY...ALG WITH A DEEPENING
MOIST SUPPLY...THE MAIN UPPER-LVL WAVE IS RATHER FLAT AND FAST
MOVG...AND THIS RAPID SYSTEM MOVEMENT COULD WELL KEEP PCPN AMTS
DOWN. MY GUT FEELING IS THAT MODEL QPF`S OF 0.3-0.5" LIQUID ARE A
BIT OVERDONE...BUT EVEN IF THEY ARE...SEVERAL INCHES OF SNOW ARE
STILL PSBL. WE`LL ALSO HAVE TO WATCH FOR THE PSBLTY THAT AN
ELEVATED WARM LYR BECOMES INCORPORATED...WHICH COULD POTENTIALLY
CREATE A WINTRY MIX SITN FOR PTNS OF THE FA. WE`LL BE MONITORING
THIS SYSTEM CLOSELY OVER THE NEXT COUPLE OF DAYS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
PATTERN OF A GENERAL SOUTHWEST FLOW WITH OCCASIONAL WAVES...WILL
ALTERNATE US ON EITHER SIDE OF THE 540 DECAMETER LINE IN REGARDS
TO 1000-500MB THICKNESS. REGARDLESS OF PRECIPITATION TYPE DURING
THE PERIOD...IT WILL BE A WARMER THAN NORMAL PATTERN FOR LATE
JANUARY...A THEME THAT HAS DOMINATED MOST OF THIS WINTER SO FAR.
WE BEGIN SATURDAY NIGHT THROUGH SUNDAY MORNING...BETWEEN WAVES
WITH SEASONABLY COLD LOWS AND MAINLY DRY WEATHER. AN EXTENSION OF
A SOUTHERN STREAM UPPER WAVE MAY SKIM US LATE SUNDAY INTO MONDAY
MORNING. IF PRECIPITATION MANAGES TO REACH US...GENERAL SET UP AND
GFS MODEL SOUNDINGS SUGGEST THERE IS SOME PROSPECT FOR A LIGHT
WINTRY MIX INITIALLY BEFORE PLAIN RAIN. GFS/ECWMF AGREE BETTER
THOUGH...ON A NORTHERN STREAM TROUGH THEN SWINGING THROUGH LATE
MONDAY OR MONDAY NIGHT. THE COLD AIR BEHIND THAT SYSTEM LOOKS
PRETTY MEAGER...SO UNLESS BETTER PENETRATION OF COLDER AIR
OCCURS...THE RESULTING LAKE RESPONSE ON TUESDAY ALSO LOOKS
MEDIOCRE. WE MAY END UP JUST HAVING SCATTERED SNOW SHOWERS SIMPLY
FROM SYNOPTIC WRAP AROUND/COMMA HEAD OF SYSTEM...WITH NOT A WHOLE
LOT OF ASSISTANCE FROM THE LAKES. THE DOMINANT SOUTHWEST FLOW
QUICKLY BRINGS IN WARMER AIR AND SURFACE HIGH PRESSURE INTO
WEDNESDAY...AND TEMPERATURES LOOK TO BE ROUGHLY 10 DEGREES ABOVE
NORMAL AT THAT TIME. NORTH ATLANTIC OSCILLATION INDEX IS POSITIVE
NOW...AND IS FORECAST TO REMAIN POSITIVE THIS WEEK...SUPPORTING
THE WARMER THAN NORMAL PATTERN.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL WEAKEN TODAY AS A LOW PRESSURE SYSTEM
APPROACHES THE REGION FROM THE WEST. HIGH CLOUDS WILL MOVE IN
LATER THIS MORNING. VFR CONDITIONS WILL LAST UNDER A HIGH TO MID
DECK OF CLOUDS UNTIL THE VERY LATE AFTERNOON OR EARLY EVENING.
THEN CIGS WILL DROP TO MVFR AND LIGHT SNOW SHOWERS WILL BEGIN TO
MOVE IN. A COLD FRONT WILL THEN CROSS THE AREA TONIGHT, AROUND
MIDNIGHT. A AREA OF HEAVIER SNOW IS EXPECTED ALONG WITH THE FRONT,
WHICH MAY BRING A PERIOD OF IFR CIGS AND VSBYS TO MOST TAF SITES,
ESPECIALLY FURTHER NORTH, SUCH AS SYR AND RME. CONDITIONS SHOULD
BEGIN TO IMPROVE IN THE PREDAWN HOURS TOMORROW MORNING BEHIND THE
FRONT, WITH THE EXCEPTION OF RME AND SYR, WHERE LAKE EFFECT SNOW
IS EXPECTED TO DEVELOP ONCE AGAIN.
WINDS WILL PICK UP OUT OF THE SOUTH THIS MORNING BETWEEN 5 AND 10
KTS. AS THE PRESSURE GRADIENT INCREASES, WITH THE LOW APPROACHING,
WINDS WILL INCREASE TO AROUND 15KTS WITH GUSTS TO AROUND 25 KTS.
THE GUSTS WILL LAST UNTIL THE FRONTAL PASSAGE AND WILL AFFECT
VSBYS WITH BLSN. BEHIND THE FRONT, WINDS WILL TURN WNW BETWEEN 5
AND 10 KTS.
.OUTLOOK...
LATE THURSDAY TO FRIDAY...MVFR. LIGHT SNOW CHANGING TO LAKE
EFFECT SNOW IN NY BY FRIDAY.
SATURDAY...MVFR IN SNOW SHOWERS.
SUNDAY...MAINLY VFR.
MONDAY..MVFR POSSIBLE IN RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 9 AM EST
FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...MDP
AVIATION...SLI
AREA FORECAST DISCUSSION
NWS RALEIGH NC
925 PM EST FRI JAN 20 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING
UNSETTLED WEATHER TO THE CAROLINAS AND SOUTHERN VIRGINIA THROUGH
SATURDAY NIGHT. AN AREA OF HIGH PRESSURE WILL BUILD SOUTH INTO OUR
REGION SUNDAY...BRINGING DAMP AND CHILLY CONDITIONS. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 925 PM FRIDAY...
LIGHT RAIN AND A WEDGE LIKE AIRMASS HAVE DEVELOPED FROM CENTRAL NC
TO NORTHERN GA THIS EVENING...WHILE A WARM FRONT IS STARTING TO LIFT
THROUGH AL AS A WEAK LOW PRESSURE DEVELOPS OVER AR. THE LIGHT
RAIN...SUPPORTED BY ISENTROPIC LIFT ALONG AND NORTH OF THE WEDGE
FRONT/WEAK 850MB WARM FRONT AND DIFFLUENT FLOW IN THE EXIT OF A WEAK
300MB JET AXIS STRETCHED ACROSS THE LOWER MS VALLEY...CONTINUES TO
BLOSSOM TO OUR SOUTHWEST AND SPREAD ACROSS CENTRAL NC. THE ONGOING
RAINFALL IS LIGHT AND RAINFALL TOTALS HAVE BEEN BELOW A TENTH OF AN
INCH. RUC ISENTROPIC LIFT FORECASTS SHOW STRONG LIFT CONTINUING IN
THE 290-300K LAYER THROUGH 09Z BEFORE SOME DRIER AIR ALOFT..NOTED AT
700MB...ADVECTS IN FROM THE SOUTHWEST AHEAD OF THE TROUGH AXIS TO
APPROACH LATER IN THE DAY SATURDAY. THUS..RAIN IS LIKELY TO TURN TO
DRIZZLE FROM WEST TO EAST AFTER 09Z..BUT CATEGORICAL POPS SEEM
NECESSARY EVERYWHERE FOR THE BALANCE OF THE NIGHT.
WITH A 5K FT WEDGE AIRMASS (PER 00Z KGSO RAOB) LOCKING IN...THE
CURRENT FORECAST OF TEMPS IN THE LOW TO MID 40S WILL REMAINING
NEARLY STEADY OR RISING SLIGHTLY LOOKS GOOD. -SMITH
THE WARM ADVECTION DRIVEN PRECIP SHOULD COME TO AN END FROM WEST TO
EAST BY EARLY SATURDAY MORNING. HOWEVER...THE LULL IN PRECIP WILL BE
SHORT LIVED AS A COLD FRONT ADVANCES TOWARDS THE AREA DURING THE DAY
ON SATURDAY. SOUTHWESTERLY FLOW AHEAD OF THE FRONT WILL PUMP WARM
AND MOIST AIR INTO THE REGION...WITH MAX TEMPS EXPECTED TO RISE INTO
THE 60S AREAWIDE (MAYBE EVEN PUSHING 70 DEGREES ACROSS THE
SOUTHEAST). ALTHOUGH SOME DIURNAL DESTABILIZATION IS EXPECTED TO
OCCUR ACROSS THE EASTERN HALF OF THE FORECAST AREA...DEWPOINTS ARE
ONLY EXPECTED TO REACH INTO THE LOW TO MID 50S...THUS LIMITING THE
AMOUNT OF INSTABILITY. NAM FORECAST SOUNDINGS SHOW AT BEST CAPE
VALUES OF LESS THAN 500 J/KG...WHILE THE GFS FORECAST SOUNDINGS SHOW
NO INSTABILITY AT ALL. NEVERTHELESS...DECENT SHEAR WILL BE IN PLACE
OVER THE REGION AND IF WE ARE ABLE TO REALIZE SOME OF THE
INSTABILITY THE NAM INDICATES...AN ISOLATED THUNDERSTORM OR TWO
CANNOT BE RULED OUT SATURDAY AFTERNOON. HOWEVER...FOR NOW WILL LEAVE
ANY MENTION OF THUNDER OUT OF THE FORECAST DUE TO THE UNCERTAINTY.
OVERALL...AFTER THE BRIEF LULL IN PRECIP SATURDAY MORNING...AM
EXPECTING A LINE OF SHOWERS TO PROGRESS FROM NORTHWEST TO SOUTHEAST
SATURDAY AFTERNOON/EVENING.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 250 PM FRIDAY...
ON SATURDAY EVENING...SHOWERS WILL BE ONGOING AS THE UPPER TROUGH
AND ASSOCIATED COLD FRONT PUSHES ACROSS THE REGION. THE EC AND NAM
HAVE TRENDED FASTER WITH DROPPING THE SFC COLD FRONT SOUTH THROUGH
THE AREA SHORTLY AFTER MIDNIGHT SATURDAY NIGHT WITH SHOWERS
TRANSITIONING TO RAIN AND THEN DRIZZLE FROM NW TO SE ACROSS CENTRAL
NC AS WE LOSS MID AND UPPER LEVEL SATURATION AS DRYING AND
SUBSIDENCE ALOFT SPREAD INTO THE AREA BEHIND THE EXITING SHORTWAVE
TROUGH.
A STRENGTHENING +1030MB SURFACE COLD AIR HIGH OVER NEW ENGLAND
WILL ADVECT COLDER AND DRIER AIR INTO CENTRAL NC DURING THE PREDAWN
HOURS...AND THIS WILL SET THE STAGE FOR A SHORT-LIVED HYBRID DAMMING
EVENT ON SUNDAY AS CONTINUED SWLY FLOW ALOFT WILL SUPPORT WEAK
OVERRUNNING ACROSS CENTRAL NC AS THE NEXT PACIFIC TROUGH PUSHES EAST
INTO THE CENTRAL US. WITH MOIST COLUMN NOT EXTENDING MUCH BEYOND
700MB...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE EXPECTED WITH
PERIODS OF DRIZZLE THROUGHOUT THE DAY...WITH THE POTENTIAL THAT
THE NORTHWEST PIEDMONT COULD SEE A BRIEF PERIOD OF FREEZING DRIZZLE
EARLY SUNDAY MORNING AS MODEL SOUNDINGS DRIVE SFC TEMPERATURES
SUNDAY MORNING INTO THE LOWER TO MID 30S WITH WET BULB-FREEZING LINE
DEPICTED IN THE SAME CLIMATOLOGICALLY FAVORED AREA AS WELL.
FURTHERMORE A HANDFUL OF SREF MEMBERS ALSO INDICATE A BRIEF
CHANGEOVER OF FREEZING DRIZZLE WITH LITTLE TO NO ACCUMULATION( A
COUPLE OF HUNDREDTHS OR LESS). SFC WET-BULBS ARE EXPECTED
TO REBOUND INTO THE MID 30S THROUGH THE MORNING WITH MINIMAL
RECOVERY THROUGHOUT THE DAY. AFTER MORNING LOWS IN THE MID TO UPPER
30S NORTH TO MID 40S SOUTH...EXPECT A NET INCREASE OF ONLY 3 TO 5
DEGREES ACROSS THE AREA.
STALLED FRONTAL ZONE SOUTH OF THE AREA BEGINS TO RETREAT NORTHWARD
AS A WARM FRONT SUNDAY NIGHT...WITH THE SOUTHERN RETURN FLOW
OVERTAKING THE SHALLOW CAD AIRMASS ALONG THE SOUTHERN AND EASTERN
FLANKS...WHILE REMAINING LOCKED IN OVER THE NW PIEDMONT REGION. THIS
WILL FAVOR NEAR STEADY TEMPERATURES OVERNIGHT ACROSS THE NW WITH
TEMPERATES SLIGHTLY RISING ACROSS THE SANDHILLS AND COASTAL
COUNTIES.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 250 PM FRIDAY...
MONDAY AND MONDAY NIGHT: LINGERING WEDGE REGIME SHOULD UNDERGO A
RELATIVELY QUICK DEMISE OWING TO SURFACE DIVERGENCE AS PROGRESSIVE
SURFACE HIGH OVER NEW ENGLAND PULLS OUT TO SEA...AND STRONG
SHEAR-INDUCED MIXING VIA STRENGTHENING SWLY FLOW OF 35 TO 40KTS AS
THE UPPER TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST.
TEMPERATURES BREAK OUT IN THE LOWER TO UPPER 60S ON MONDAY AFTERNOON
WITH BREEZY SWLY WINDS WITH A LULL IN PRECIP MONDAY MORNING...BEFORE
RAIN CHANCES RAMP BACK UP BY THE AFTERNOON WITH THE TRAILING SURFACE
COLD FRONT MOVING THROUGH THE AREA BETWEEN MONDAY 18Z TO 06Z.
INSTABILITY IS EXPECTED TO BE LIMITED BY WIDESPREAD
CLOUDS...ESPECIALLY IF THE FASTER GFS VERIFIES...BUT GIVEN STRONG
DEEP LAYER SHEAR...SOME STRONG STORMS ARE POSSIBLE. TOO EARLY TO
INCLUDE A MENTION OF THUNDER AT THIS TIME...BUT WILL CONTINUE TO
MONITOR.
TEMPERATURES WILL REMAIN ABOVE NORMAL WITH DRY CONDITIONS TUESDAY
THROUGH WEDNESDAY AS AS WE WAIT FOR THE NEXT PACIFIC SHORTWAVE
TROUGH TO TAKE A MORE SOUTHERN ROUTE THROUGH THE SOUTHERN US. NWP
MODEL GUIDANCE DIVERGE BY THURSDAY...WITH HIGH UNCERTAINTY REGARDING
WHETHER TO PHASE THE SOUTHERN STREAM STORM SYSTEM WITH NORTHERN
STREAM ENERGY AND EVOLVE IT INTO AN OPEN WAVE OR TO KEEP THE
SOUTHERN STORM SYSTEM CUT-OFF FROM THE MAIN BELT OF
WESTERLIES...WHILE HOLDING IT BACK ACROSS THE TEXAS/SOUTHERN PLAINS.
GIVEN LOW CONFIDENCE...WILL REMAIN CONSERVATIVE WITH POPS...WITH
SLIGHT TO SMALL CHANCE POPS FROM WEDNESDAY NIGHT ON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 713 PM FRIDAY...
CONDITIONS WILL GRADUALLY DETERIORATE TO MVFR/IFR CONDITIONS THROUGH
2 AM AS AREAS OF LIGHT RAIN SLOWLY SATURATE THE LOWER LAYERS OF THE
ATMOSPHERE. WIDESPREAD LIGHT RAIN WILL PERSIST ACROSS CENTRAL NC
THROUGH 3 AM...AFTERWHICH THE RAIN WILL GRADUALLY DIMINISH TO SPOTTY
DRIZZLE AND SOME FOG. BY 9-11 AM SATURDAY...CEILINGS MAY TEMPORARILY
LIFT INTO THE LOW END VFR CATEGORY AS SURFACE WINDS WILL BECOME SLY
AND INCREASE TO 10-15KTS WITH GUSTS 20-25 KTS. AN AREA OF SHOWERS
SHOULD OVERSPREAD CENTRAL NC LATE SATURDAY AND SATURDAY NIGHT AS A
COLD FRONT CROSSES THE REGION. BEHIND THE FRONT...THE SHOWERS WILL
END THOUGH CEILINGS WILL BE IN THE 800-2000FT RANGE SUNDAY INTO
SUNDAY NIGHT. AREAS OF FOG MAY BE PROBABLE BY SUNDAY NIGHT AS SLY
WINDS JUST ABOVE THE SURFACE ADVECT WARMER AIR OVER THE COOLER
STABLE AIR NEAR THE SURFACE.
MONDAY...CEILINGS EXPECTED TO REMAIN IFR/MVFR AS ANOTHER COLD FRONT
CROSSES THE REGION WITH SHOWERS OCCURRING AHEAD OF THE FRONT. THE
SHOWERS ARE MOST LIKELY TO OCCUR MONDAY AFTERNOON. THE FRONT WILL
EXIT THE REGION MONDAY NIGHT. NW FLOW BEHIND THE FRONT WILL USHER
DRIER MORE STABLE AIR INTO THE REGION...ENDING THE SHOWERS AND
DISSIPATING CLOUD COVERAGE. VFR CONDITIONS CURRENTLY ANTICIPATED FOR
TUESDAY AND WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...KRR/SMITH
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
706 PM EST FRI JAN 20 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT AND
REACH THE CAROLINAS SATURDAY. HIGH PRESSURE WILL RETURN FOR THE
SECOND HALF OF THE WEEKEND. A FRONT WILL MOVE ACROSS THE REGION
MONDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
ONLY MADE A FEW TWEAKS TO HOURLY TEMPS THE NEXT COUPLE OF HOURS.
OTHERWISE ALL REMAINS ON TRACK WITH A SOLID ADVISORY CRITERIA
SNOWFALL. THE SNOW WILL CONTINUE TO SPREAD EAST RAPIDLY THIS
EVENING. THE RUC MODEL IS A LITTLE SLOW IN SPREADING THE
SNOW...THIS MAY BE TOO SLOW. THE LOW LEVELS ARE DRY...SO AS SOON
AS IT MOISTENS UP THE VISIBILITY IN SNOW WILL DROP QUICKLY. ON THE
EDGE ABOUT WHETHER ANY AREAS NEED TO BE UPGRADED TO A WARNING. AT
THIS TIME GOING MORE WITH THE GFS/SREF/ECMWF TRACK OF THE LOW...
WHICH WILL KEEP IT MAINLY SNOW AND SHOULD HAVE THE HEAVIEST
AMOUNTS SOUTH OF THE FORECAST AREA. WILL ADD A CHANCE OF SLEET AND
FREEZING RAIN TO A FEW OF THE SOUTHERN COUNTIES AS THE 850 MB
TEMPERATURE WARMS. THE AREAS THAT COULD GET OVER 6 INCHES COULD BE
THE LAKESHORE AREAS AS THE FLOW BECOMES NORTHEAST FOR A FEW HOURS
LATE TONIGHT AND WE GET SOME ENHANCEMENT. THE OTHER AREAS WOULD BE
A WEST TO EAST BAND OF HEAVY SNOW FROM FDY TO MFD TO THE
YOUNGSTOWN AREA. THE OMEGA AND SNOW GROWTH IS NOT THAT IMPRESSIVE.
THE SNOW COULD BE A LITTLE FLUFFY FOR A WHILE WITH THE COLD
TEMPERATURES AT FIRST. AFTER CAREFUL CONSIDERATION WILL NOT
UPGRADE. WILL DEFINITELY HAVE SOME GRIDS WITH A THREAT OF HEAVY
SNOW IN THEM. TEMPERATURES WILL RISE SOME AND THEN HOLD STEADY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
SOME LEFT OVER SNOW IN THE AM...MAINLY EARLY. THE AIRMASS DRIES OUT
QUICKLY SATURDAY AM. THE BUFKIT NAM IS TRYING TO INDICATE SOME
FREEZING DRIZZLE SATURDAY MORNING...AT THIS TIME WILL NOT FORECAST
IT AS THE AIRMASS SHOULD DRY OUT RAPIDLY AND THE CLOUDS DECREASE. ON
THE EDGE ABOUT THE LOWS SATURDAY NIGHT WITH MOSTLY CLEAR
SKIES...SOME CIRRUS...A LITTLE WIND AND WARMING ALOFT. IF HIGH
PRESSURE WAS OVER THE AREA IT WOULD BE VERY COLD BECAUSE OF THE SNOW
COVER. DID GO ON THE COLDER SIDE OF THE GFS MOS.
INCREASING CLOUDS IN THE WARM ADVECTION SUNDAY. A THREAT OF SHOWERS
IN THE WEST BY LATE AFTERNOON. OTHERWISE AN INCREASING THREAT OF
SHOWERS SUNDAY NIGHT AND THEN AS THE COLDER AIR COMES IN MONDAY THE
RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS. NO THUNDER ATTM BUT THIS
WILL HAVE TO BE WATCHED. THE ONLY TIMING WAS TO MENTION THAT IT
WOULD BE IN THE AFTERNOON...IT COULD BE LATE AFTERNOON OVER THE
EASTERN COUNTIES. SOME LAKE ENHANCED SNOW SHOWERS MAY OCCUR MONDAY
NIGHT IN THE SNOW BELT...THE LAKE AND 850 MB TEMPERATURE
DIFFERENCE WILL BE NEAR 12C.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THERE MAY BE SOME LINGERING SNOW SHOWERS INTO EARLY TUESDAY
AFTERNOON. HIGH PRESSURE WILL THEN GAIN CONTROL OF THE REGION
TUESDAY NIGHT AND CONTINUE INTO WEDNESDAY. THE NEXT STORM SYSTEM
LOOKS LIKE IT WILL APPROACH FROM THE SOUTHERN PLAINS WEDNESDAY NIGHT
INTO THURSDAY AS A CLIPPER TYPE SYSTEM MOVES THROUGH THE NORTHERN
JET STREAM. THIS WILL BE A SIMILAR EVENT TO WHAT IS OCCURRING
TONIGHT BUT THE REGION WILL BE SLIGHTLY WARMER. THIS MAY END UP
PRODUCING A WINTRY MIX BEFORE CHANGING OVER TO RAIN. MODELS DIFFER
ON THE THE TIMING WITH THIS STORM SYSTEM SO ONLY WENT WITH CHANCE
POPS AT THIS TIME.
AFTER HIGHS IN THE MIDDLE 30S ON TUESDAY IT APPEARS THAT HIGHS WILL
WARM TO AROUND 40 WEDNESDAY INTO THURSDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE SNOW AND IFR CONDITIONS WILL MOVE QUICKLY EAST EARLY TONIGHT
REACHING NORTHWEST PENNSYLVANIA BY 03Z OR SO. THE SNOW WILL BE
MODERATE TO HEAVY FOR 4-5 HOURS WITH LIFR CONDITIONS POSSIBLE
DURING THIS TIME. THE SNOW WILL END FROM WEST TO EAST SATURDAY
MORNING 08Z-13Z. VISIBILITIES WILL IMPROVE TO VFR WHEN THE SNOW
STOPS BUT MVFR CEILINGS WILL LINGER FOR A WHILE. VFR CEILINGS
(035BKN) WILL DEVELOP SATURDAY AFTERNOON WITH CLEARING SOON AFTER.
VFR AND CLEAR SAILING SATURDAY NIGHT.
.OUTLOOK...NON VFR CONDITIONS WILL REDEVELOP MONDAY IN RAIN
SHOWERS...RAIN WILL TURN TO SNOW MONDAY NIGHT...SNOW WILL LINGER
INTO TUESDAY ACROSS NE OH/NW PA.
&&
.MARINE...
NORTHEAST WINDS OF 10-20 KNOTS WILL DEVELOP OVERNIGHT AS LOW
PRESSURE TRACKS THROUGH THE LOWER OHIO VALLEY. WAVES IN THE
NEARSHORE WATERS WILL BUILD NEAR THE ISLANDS...POSSIBLY
APPROACHING 4 FEET FOR A BRIEF WINDOW SATURDAY MORNING. AT THIS TIME
IT LOOKS TOO MARGINAL...ESPECIALLY WITH SOME ICE DEVELOPING ALONG
THE SHORELINE FOR A SMALL CRAFT ADVISORY. WE WILL TAKE ANOTHER LOOK
AT HOW WINDS DO OVERNIGHT BEFORE MAKING THE FINAL CALL. THIS SYSTEM
WILL QUICKLY PASS TO THE EAST ON SATURDAY AS HIGH PRESSURE BUILDS
OVER THE CENTRAL GREAT LAKES.
THE NEXT LOW PRESSURE SYSTEM TO WATCH WILL EVOLVE OUT OF THE PLAINS
AND APPROACH THE WESTERN AND UPPER GREAT LAKES ON MONDAY. THIS WILL
RESULT IN INCREASING SOUTHERLY WINDS...VEERING TO SOUTHWEST BEHIND A
COLD FRONT LATE IN THE DAY. SMALL CRAFT ADVISORIES MAY BE NEEDED EARLY
NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 9 AM EST SATURDAY FOR OHZ010>014-
020>023-029>033-037-038-047-089.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SATURDAY FOR OHZ003-
006>009-017>019-027-028-036.
PA...WINTER WEATHER ADVISORY UNTIL 9 AM EST SATURDAY FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA/OUDEMAN
SHORT TERM...KIELTYKA
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...KEC
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1113 PM CST WED JAN 18 2012
.AVIATION...
LOW CONFIDENCE ON WIND GUSTS REACHING 40 KNOTS OR HIGHER AT THE
AMARILLO TAF SITE TONIGHT. IT APPEARS THAT THE STRONGEST WINDS WILL
REMAIN WEST OF THE AMARILLO TAF SITE. THEREFORE...WILL CARRY WESTERLY
WINDS 15 TO 25 OR 30 KNOTS WITH HIGHER GUSTS BRIEFLY UNTIL AROUND 08Z
TO 10Z THURSDAY AT AMARILLO. OTHERWISE...SOUTHWESTERLY TO WESTERLY
WINDS 10 TO 20 KNOTS TONIGHT. WEAK BACKDOOR COLD FRONT WILL AFFECT
THE GUYMON TAF SITE THURSDAY CAUSING THE WINDS TO BECOME
SOUTHEASTERLY TO NORTHEASTERLY 5 TO 15 KNOTS AFTER 15Z THURSDAY. AT
THE DALHART AND AMARILLO TAF SITES...WINDS WILL BECOME MORE SOUTHERLY
OR SOUTHWESTERLY 5 TO 15 KNOTS AFTER 16Z TO 20Z THURSDAY.
CONSIDERABLE HIGH LEVEL CLOUDINESS WILL ALLOW VFR CONDITIONS TO PREVAIL.
SCHNEIDER
&&
.PREV DISCUSSION... /ISSUED 1005 PM CST WED JAN 18 2012/
UPDATE...
MAIN CHANGE WAS TO LOWER WIND SPEEDS TONIGHT...MAINLY ACROSS THE
WESTERN AND SOUTHWESTERN TEXAS PANHANDLE.
DISCUSSION...
STILL A LOW CONFIDENCE FORECAST WITH RESPECT TO WIND SPEEDS
OVERNIGHT. TUCUMCARI WIND PROFILER DATA INDICATES 0-1 KM FLOW HAS
INCREASED SUBSTANTIALLY OVER THE LAST FEW HOURS IN RESPONSE TO
STRENGTHENING LOW-LEVEL JET. SOME OF THIS HIGHER MOMENTUM AIR
IS BEING MIXED TO THE GROUND AS EVIDENCED BY RECENT OBSERVATIONS AT
KTCC. IT APPEARS THAT THE LOW-LEVEL JET IS BEGINNING TO EXPAND
EASTWARD AS HEREFORD HAS RECENTLY REPORTED GUSTS UP TO 26 MPH.
LATEST NAM...HRRR...AND RUC GUIDANCE CONTINUE TO SUGGEST THE
STRONGEST WINDS WILL REMAIN SOUTH AND WEST OF A LINE FROM DALHART TO
CLARENDON. BOTH THE RUC AND NAM SHOW THE 0-1 KM FLOW WILL BE 30-40
KT ACROSS THESE AREAS THROUGH 3 AM. HOWEVER...THE RUC REMAINS THE
MOST AGGRESSIVE WITH THE WIND POTENTIAL OVERNIGHT...MAINLY DUE TO
KEEPING THE NEAR-GROUND LAYER MIXED AND ALLOWING THE HIGHER MOMENTUM
AIR TO BE TRANSPORTED DOWNWARD. THE NAM LARGELY KEEPS THE BOUNDARY
LAYER DECOUPLED AND IS MUCH WEAKER WITH 0-1 KM LAPSE RATES. AM
SOMEWHAT CONCERNED THAT SURFACE TEMPERATURES ACROSS EASTERN NEW
MEXICO AND PARTS OF OLDHAM AND DEAF SMITH COUNTIES HAVE INCREASED
WITHIN THE LAST HOUR. THIS SUGGESTS THAT THE NEAR-GROUND LAYER IS
REMAINING MIXED AND THE RUC COULD BE ONTO SOMETHING. IF THE RUC
VERIFIES...COULD SEE WINDS 25-35 MPH WITH GUSTS TO 45 MPH ACROSS THE
SOUTHWESTERN TEXAS PANHANDLE. HOWEVER...BOTH THE NAM AND HRRR SUGGEST
VERY LITTLE MIXING OVERNIGHT...WHICH SHOULD KEEP WINDS 20-25 MPH WITH
GUSTS UP TO 35 MPH. ADDITIONALLY...LATEST MET GUIDANCE...WHICH HAD
PREVIOUSLY BEEN AGGRESSIVE WITH THE WINDS...HAS BACKED OFF
SIGNIFICANTLY. LEANED MORE HEAVILY TOWARDS THE NAM...HRRR...AND
LATEST MET GUIDANCE...SO WE LOWERED WIND SPEEDS. STILL NOT EXPECTING
WINDS TO BE STRONG ENOUGH TO REACH ADVISORY CRITERIA...BUT IT COULD
STILL BE BREEZY TO WINDY AT TIMES THROUGH 3 AM. UPDATED PRODUCTS
HAVE BEEN SENT.
JACKSON
PREV DISCUSSION... /ISSUED 540 PM CST WED JAN 18 2012/
AVIATION...
BIGGEST AVIATION CONCERN WILL BE WIND SPEEDS TONIGHT...MAINLY BETWEEN
03Z AND 09Z THURSDAY. WINDS JUST ABOVE THE SURFACE EXPECTED TO
INCREASE FROM THE WEST TO AROUND 40 TO 50 KNOTS BETWEEN 03Z AND 09Z
THURSDAY...AND THE TUCUMCARI PROFILER SHOWED A 10 KNOT JUMP IN WIND
SPEEDS BETWEEN 22Z AND 23Z WEDNESDAY AROUND THE THIRD AND FOURTH
GATES. THE MAIN CONCERN WILL BE THE AMARILLO TAF WHERE SOME 40 KNOT
OR HIGHER GUST MAY OCCUR JUST PRIOR TO 06Z THURSDAY...AND JUST AFTER
06Z THURSDAY. MAY NEED AN AVIATION WEATHER ADVISORY FOR THE AMARILLO
AIRPORT TONIGHT FOR A BRIEF WINDOW...HOWEVER CONFIDENCE JUST A BIT
TOO LOW AT THE MOMENT TO ISSUE. WILL CONTINUE TO MONITOR CLOSELY.
OTHERWISE...VFR CONDITIONS WITH HIGH LEVEL CLOUDINESS THROUGH 00Z
FRIDAY. WESTERLY TO SOUTHWESTERLY AND SOUTHERLY WINDS 10 TO 20
KNOTS WITH SOME HIGHER GUSTS POSSIBLE...THE EXCEPTION BEING BETWEEN
03Z AND 09Z THURSDAY AT THE AMARILLO TAF SITE.
SCHNEIDER
PREV DISCUSSION... /ISSUED 359 PM CST WED JAN 18 2012/
DISCUSSION...
FOCUS OF THIS FORECAST REMAINS ON TEMPERATURES THROUGH THE
WEEKEND...THEN SHIFTS TO PRECIPITATION PROSPECTS EARLY NEXT WEEK.
A STRONG UPPER JET STRETCHED FROM THE PAC NW SOUTHEAST ACROSS THE
NORTHERN ROCKIES INTO THE CENTRAL PLAINS THIS AFTERNOON. LEE ENHANCED
CIRRUS ON THE SOUTH SIDE OF THE JET HAS PRODUCED A CIRRUS CANOPY
ACROSS THE PANHANDLES TODAY...WHICH HAS BEEN FAIRLY THICK AT TIMES.
THIS HAS DELAYED THE WARMUP TO SOME DEGREE TODAY...BUT A STEADY CLIMB
THROUGH THE DAY HAS ALLOWED TEMPS TO REACH THE MID 50S TO LOWER 60S
LATE THIS AFTERNOON. WEST/SOUTHWEST DOWNSLOPE WINDS TO THE EAST OF A
LEE SURFACE TROUGH OVER EASTERN CO/NM HAVE AIDED THE WARMUP.
A BREEZY TO WINDY AND RATHER MILD NIGHT FOR JANUARY IS EXPECTED FOR
THE PANHANDLES TONIGHT. THE SURFACE TROUGH WILL ADVANCE EAST ACROSS
THE AREA TONIGHT...SETTING UP A DECENT PRESSURE GRADIENT ACROSS
WESTERN AND CENTRAL PORTIONS OF THE CWA. A WESTERLY 50 KT LLJ IS ALSO
PROGGED TONIGHT. THUS...EXPECT BREEZY TO WINDY CONDITIONS THIS
EVENING AND OVERNIGHT ACROSS WESTERN AND CENTRAL AREAS...WHICH WILL
KEEP TEMPS UP. HAVE THUS GONE SEVERAL DEGREES ABOVE MOS GUIDANCE WITH
FORECAST LOWS. CIRRUS MAY ALSO HOLD TEMPS UP A TAD...ALTHOUGH IT IS
EXPECTED TO THIN LATER TONIGHT. WINDS WILL BE LIGHTER AND TEMPS
COOLER ACROSS EASTERN AREAS MORE WITHIN THE SURFACE TROUGH AXIS.
A COLD FRONT WILL BACK ITS WAY INTO THE AREA ON THURSDAY...SETTING UP
A FAIRLY STRONG SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT OF ABOUT
20 DEGREES ACROSS THE CWA. THE PRESSURE GRADIENT WILL ALSO RELAX WITH
THIS BOUNDARY PUSHING INTO THE AREA. WINDS MAY BE BREEZY ACROSS THE
WEST/SOUTHWEST IN THE MORNING...BUT SHOULD DISSIPATE IN THE
AFTERNOON.
A ZONAL FLOW ALOFT WILL BE IN PLACE ACROSS THE CONUS ON FRIDAY. A
FAST-MOVING MID/UPPER-LEVEL SHORTWAVE WILL MOVE EAST ACROSS THE
CENTRAL PLAINS AND CLIP THE PANHANDLES FRIDAY AFTERNOON AND
EVENING...SENDING A WEAK COLD FRONT SOUTH DURING THIS TIME AS WELL.
STILL SOME SUBTLE TIMING DIFFERENCES WITH THE SHORTWAVE AND
FRONT...WHICH ISN/T SURPRISING CONSIDERING THE FAST ZONAL FLOW. WILL
SEE BREEZY TO WINDY WEST WINDS SOUTH OF THE FRONT...WITH WINDS
DECREASING AND TURNING TO THE NORTH IN ITS WAKE. FRONTAL TIMING MAKES
FOR A TRICKY TEMPERATURE FORECAST...BUT WILL AIM FOR LOWER 50S
NORTHEAST TO AROUND 70F IN THE FAR SOUTH FOR NOW. LOW-LEVELS APPEAR
WAY TOO DRY FOR THE SHORTWAVE TO SQUEEZE OUT ANY PRECIP.
LEE TROUGHING WILL QUICKLY RE-DEVELOP ON SATURDAY BENEATH A CONTINUED
ZONAL FLOW ALOFT. SOUTH/SOUTHWEST WINDS WILL RETURN IN RESPONSE...AND
UNSEASONABLY WARM CONDITIONS WILL CONTINUE. ANOTHER SHORTWAVE WILL
MOVE ACROSS SATURDAY NIGHT/SUNDAY...SENDING ANOTHER WEAK COLD FRONT
THROUGH. AGAIN...THIS WAVE LOOKS TO BE MOISTURE STARVED AND THE FRONT
WILL HAVE LITTLE EFFECT ON TEMPERATURES. WARM...DRY CONDITIONS TO
PERSIST THROUGH MONDAY AHEAD OF THE NEXT UPPER TROUGH WORKING ACROSS
THE WEST.
THERE REMAINS QUITE A BIT OF UNCERTAINTY REGARDING THE POTENTIAL
SYSTEM FOR EARLY TO MID NEXT WEEK. MODEL SOLUTIONS CONTINUE TO WAVER
BETWEEN A CLOSED LOW AND A PROGRESSIVE OPEN WAVE AFFECTING THE
PANHANDLES CENTERED ON THE TUESDAY TIMEFRAME. LATEST 12Z RUNS OF THE
GFS AND ECMWF ARE BOTH NOW ADVERTISING AN OPEN WAVE AND ONLY MINIMAL
PRECIPITATION CHANCES. WILL MAINTAIN SOME SMALL POPS TUESDAY
ATTM...AND SEE HOW LATER RUNS TREND. DID WARM TEMPS SLIGHTLY ON
TUESDAY AND TRIMMED THE RAIN/SNOW MIX BACK TO THE NORTHWEST. DRY BUT
COOLER CONDITIONS THEN EXPECTED WEDNESDAY BEHIND THE DEPARTING UPPER
TROUGH/LOW.
KB
FIRE WEATHER...
A COLD FRONT WILL BACK INTO THE EASTERN OKLAHOMA PANHANDLE AND
NORTHEAST TEXAS PANHANDLE ON THURSDAY...SETTING UP A SOUTHWEST TO
NORTHEAST TEMPERATURE GRADIENT ACROSS THE AREA. THIS FRONT WILL ALSO
KEEP WINDS LIGHTER...WITH SPEEDS EXPECTED TO REMAIN BELOW 15 MPH.
THUS...ELEVATED FIRE WEATHER CONDITIONS ARE NOT EXPECTED DESPITE
AFTERNOON RELATIVE HUMIDITIES FALLING TO 15 TO 20 PERCENT ACROSS THE
SOUTHWEST HALF OF THE PANHANDLES. UNSEASONABLY WARM TEMPERATURES WILL
CONTINUE INTO FRIDAY. WESTERLY WINDS WILL INCREASE AHEAD OF THE NEXT
COLD FRONT...WHICH IS EXPECTED TO MOVE THROUGH DURING THE AFTERNOON
OR EVENING HOURS. ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE
ACROSS THE SOUTHWEST HALF OF THE AREA...WITH CRITICAL CONDITIONS
POSSIBLE ACROSS THE SOUTHWEST AND SOUTH CENTRAL TEXAS PANHANDLE WHERE
WESTERLY WINDS WILL INCREASE TO 20 TO 30 MPH WITH HIGHER GUSTS AND
MINIMUM RELATIVE HUMIDITIES WILL FALL TO 15 TO 20 PERCENT. A FIRE
WEATHER WATCH HAS BEEN ISSUED FOR THESE AREAS. THERE IS STILL SOME
UNCERTAINTY REGARDING TIMING OF THE COLD FRONT...AND A FASTER ARRIVAL
COULD POTENTIALLY EASE FIRE WEATHER CONCERNS WHILE A SLOWER ARRIVAL
MAY ALLOW CRITICAL CONDITIONS TO DEVELOP OVER A LARGER AREA.
UNSEASONABLY WARM CONDITIONS WILL CONTINUE OVER THE WEEKEND INTO
MONDAY. COMBINED WITH BREEZY CONDITIONS...ELEVATED FIRE WEATHER
CONDITIONS WILL BE POSSIBLE SATURDAY THROUGH MONDAY ACROSS WESTERN
AND CENTRAL PORTIONS OF THE AREA.
KB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING
FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...DEAF SMITH...
OLDHAM...POTTER...RANDALL.
OK...NONE.
&&
$$
11/13
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1005 PM CST WED JAN 18 2012
.UPDATE...
MAIN CHANGE WAS TO LOWER WIND SPEEDS TONIGHT...MAINLY ACROSS THE
WESTERN AND SOUTHWESTERN TEXAS PANHANDLE.
&&
.DISCUSSION...
STILL A LOW CONFIDENCE FORECAST WITH RESPECT TO WIND SPEEDS
OVERNIGHT. TUCUMCARI WIND PROFILER DATA INDICATES 0-1 KM FLOW HAS
INCREASED SUBSTANTIALLY OVER THE LAST FEW HOURS IN RESPONSE TO
STRENGTHENING LOW-LEVEL JET. SOME OF THIS HIGHER MOMENTUM AIR
IS BEING MIXED TO THE GROUND AS EVIDENCED BY RECENT OBSERVATIONS AT
KTCC. IT APPEARS THAT THE LOW-LEVEL JET IS BEGINNING TO EXPAND
EASTWARD AS HEREFORD HAS RECENTLY REPORTED GUSTS UP TO 26 MPH.
LATEST NAM...HRRR...AND RUC GUIDANCE CONTINUE TO SUGGEST THE
STRONGEST WINDS WILL REMAIN SOUTH AND WEST OF A LINE FROM DALHART TO
CLARENDON. BOTH THE RUC AND NAM SHOW THE 0-1 KM FLOW WILL BE 30-40
KT ACROSS THESE AREAS THROUGH 3 AM. HOWEVER...THE RUC REMAINS THE
MOST AGGRESSIVE WITH THE WIND POTENTIAL OVERNIGHT...MAINLY DUE TO
KEEPING THE NEAR-GROUND LAYER MIXED AND ALLOWING THE HIGHER MOMENTUM
AIR TO BE TRANSPORTED DOWNWARD. THE NAM LARGELY KEEPS THE BOUNDARY
LAYER DECOUPLED AND IS MUCH WEAKER WITH 0-1 KM LAPSE RATES. AM
SOMEWHAT CONCERNED THAT SURFACE TEMPERATURES ACROSS EASTERN NEW
MEXICO AND PARTS OF OLDHAM AND DEAF SMITH COUNTIES HAVE INCREASED
WITHIN THE LAST HOUR. THIS SUGGESTS THAT THE NEAR-GROUND LAYER IS
REMAINING MIXED AND THE RUC COULD BE ONTO SOMETHING. IF THE RUC
VERIFIES...COULD SEE WINDS 25-35 MPH WITH GUSTS TO 45 MPH ACROSS THE
SOUTHWESTERN TEXAS PANHANDLE. HOWEVER...BOTH THE NAM AND HRRR SUGGEST
VERY LITTLE MIXING OVERNIGHT...WHICH SHOULD KEEP WINDS 20-25 MPH WITH
GUSTS UP TO 35 MPH. ADDITIONALLY...LATEST MET GUIDANCE...WHICH HAD
PREVIOUSLY BEEN AGGRESSIVE WITH THE WINDS...HAS BACKED OFF
SIGNIFICANTLY. LEANED MORE HEAVILY TOWARDS THE NAM...HRRR...AND
LATEST MET GUIDANCE...SO WE LOWERED WIND SPEEDS. STILL NOT EXPECTING
WINDS TO BE STRONG ENOUGH TO REACH ADVISORY CRITERIA...BUT IT COULD
STILL BE BREEZY TO WINDY AT TIMES THROUGH 3 AM. UPDATED PRODUCTS
HAVE BEEN SENT.
JACKSON
&&
.PREV DISCUSSION... /ISSUED 540 PM CST WED JAN 18 2012/
AVIATION...
BIGGEST AVIATION CONCERN WILL BE WIND SPEEDS TONIGHT...MAINLY BETWEEN
03Z AND 09Z THURSDAY. WINDS JUST ABOVE THE SURFACE EXPECTED TO
INCREASE FROM THE WEST TO AROUND 40 TO 50 KNOTS BETWEEN 03Z AND 09Z
THURSDAY...AND THE TUCUMCARI PROFILER SHOWED A 10 KNOT JUMP IN WIND
SPEEDS BETWEEN 22Z AND 23Z WEDNESDAY AROUND THE THIRD AND FOURTH
GATES. THE MAIN CONCERN WILL BE THE AMARILLO TAF WHERE SOME 40 KNOT
OR HIGHER GUST MAY OCCUR JUST PRIOR TO 06Z THURSDAY...AND JUST AFTER
06Z THURSDAY. MAY NEED AN AVIATION WEATHER ADVISORY FOR THE AMARILLO
AIRPORT TONIGHT FOR A BRIEF WINDOW...HOWEVER CONFIDENCE JUST A BIT
TOO LOW AT THE MOMENT TO ISSUE. WILL CONTINUE TO MONITOR CLOSELY.
OTHERWISE...VFR CONDITIONS WITH HIGH LEVEL CLOUDINESS THROUGH 00Z
FRIDAY. WESTERLY TO SOUTHWESTERLY AND SOUTHERLY WINDS 10 TO 20
KNOTS WITH SOME HIGHER GUSTS POSSIBLE...THE EXCEPTION BEING BETWEEN
03Z AND 09Z THURSDAY AT THE AMARILLO TAF SITE.
SCHNEIDER
PREV DISCUSSION... /ISSUED 359 PM CST WED JAN 18 2012/
DISCUSSION...
FOCUS OF THIS FORECAST REMAINS ON TEMPERATURES THROUGH THE
WEEKEND...THEN SHIFTS TO PRECIPITATION PROSPECTS EARLY NEXT WEEK.
A STRONG UPPER JET STRETCHED FROM THE PAC NW SOUTHEAST ACROSS THE
NORTHERN ROCKIES INTO THE CENTRAL PLAINS THIS AFTERNOON. LEE ENHANCED
CIRRUS ON THE SOUTH SIDE OF THE JET HAS PRODUCED A CIRRUS CANOPY
ACROSS THE PANHANDLES TODAY...WHICH HAS BEEN FAIRLY THICK AT TIMES.
THIS HAS DELAYED THE WARMUP TO SOME DEGREE TODAY...BUT A STEADY CLIMB
THROUGH THE DAY HAS ALLOWED TEMPS TO REACH THE MID 50S TO LOWER 60S
LATE THIS AFTERNOON. WEST/SOUTHWEST DOWNSLOPE WINDS TO THE EAST OF A
LEE SURFACE TROUGH OVER EASTERN CO/NM HAVE AIDED THE WARMUP.
A BREEZY TO WINDY AND RATHER MILD NIGHT FOR JANUARY IS EXPECTED FOR
THE PANHANDLES TONIGHT. THE SURFACE TROUGH WILL ADVANCE EAST ACROSS
THE AREA TONIGHT...SETTING UP A DECENT PRESSURE GRADIENT ACROSS
WESTERN AND CENTRAL PORTIONS OF THE CWA. A WESTERLY 50 KT LLJ IS ALSO
PROGGED TONIGHT. THUS...EXPECT BREEZY TO WINDY CONDITIONS THIS
EVENING AND OVERNIGHT ACROSS WESTERN AND CENTRAL AREAS...WHICH WILL
KEEP TEMPS UP. HAVE THUS GONE SEVERAL DEGREES ABOVE MOS GUIDANCE WITH
FORECAST LOWS. CIRRUS MAY ALSO HOLD TEMPS UP A TAD...ALTHOUGH IT IS
EXPECTED TO THIN LATER TONIGHT. WINDS WILL BE LIGHTER AND TEMPS
COOLER ACROSS EASTERN AREAS MORE WITHIN THE SURFACE TROUGH AXIS.
A COLD FRONT WILL BACK ITS WAY INTO THE AREA ON THURSDAY...SETTING UP
A FAIRLY STRONG SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT OF ABOUT
20 DEGREES ACROSS THE CWA. THE PRESSURE GRADIENT WILL ALSO RELAX WITH
THIS BOUNDARY PUSHING INTO THE AREA. WINDS MAY BE BREEZY ACROSS THE
WEST/SOUTHWEST IN THE MORNING...BUT SHOULD DISSIPATE IN THE
AFTERNOON.
A ZONAL FLOW ALOFT WILL BE IN PLACE ACROSS THE CONUS ON FRIDAY. A
FAST-MOVING MID/UPPER-LEVEL SHORTWAVE WILL MOVE EAST ACROSS THE
CENTRAL PLAINS AND CLIP THE PANHANDLES FRIDAY AFTERNOON AND
EVENING...SENDING A WEAK COLD FRONT SOUTH DURING THIS TIME AS WELL.
STILL SOME SUBTLE TIMING DIFFERENCES WITH THE SHORTWAVE AND
FRONT...WHICH ISN/T SURPRISING CONSIDERING THE FAST ZONAL FLOW. WILL
SEE BREEZY TO WINDY WEST WINDS SOUTH OF THE FRONT...WITH WINDS
DECREASING AND TURNING TO THE NORTH IN ITS WAKE. FRONTAL TIMING MAKES
FOR A TRICKY TEMPERATURE FORECAST...BUT WILL AIM FOR LOWER 50S
NORTHEAST TO AROUND 70F IN THE FAR SOUTH FOR NOW. LOW-LEVELS APPEAR
WAY TOO DRY FOR THE SHORTWAVE TO SQUEEZE OUT ANY PRECIP.
LEE TROUGHING WILL QUICKLY RE-DEVELOP ON SATURDAY BENEATH A CONTINUED
ZONAL FLOW ALOFT. SOUTH/SOUTHWEST WINDS WILL RETURN IN RESPONSE...AND
UNSEASONABLY WARM CONDITIONS WILL CONTINUE. ANOTHER SHORTWAVE WILL
MOVE ACROSS SATURDAY NIGHT/SUNDAY...SENDING ANOTHER WEAK COLD FRONT
THROUGH. AGAIN...THIS WAVE LOOKS TO BE MOISTURE STARVED AND THE FRONT
WILL HAVE LITTLE EFFECT ON TEMPERATURES. WARM...DRY CONDITIONS TO
PERSIST THROUGH MONDAY AHEAD OF THE NEXT UPPER TROUGH WORKING ACROSS
THE WEST.
THERE REMAINS QUITE A BIT OF UNCERTAINTY REGARDING THE POTENTIAL
SYSTEM FOR EARLY TO MID NEXT WEEK. MODEL SOLUTIONS CONTINUE TO WAVER
BETWEEN A CLOSED LOW AND A PROGRESSIVE OPEN WAVE AFFECTING THE
PANHANDLES CENTERED ON THE TUESDAY TIMEFRAME. LATEST 12Z RUNS OF THE
GFS AND ECMWF ARE BOTH NOW ADVERTISING AN OPEN WAVE AND ONLY MINIMAL
PRECIPITATION CHANCES. WILL MAINTAIN SOME SMALL POPS TUESDAY
ATTM...AND SEE HOW LATER RUNS TREND. DID WARM TEMPS SLIGHTLY ON
TUESDAY AND TRIMMED THE RAIN/SNOW MIX BACK TO THE NORTHWEST. DRY BUT
COOLER CONDITIONS THEN EXPECTED WEDNESDAY BEHIND THE DEPARTING UPPER
TROUGH/LOW.
KB
FIRE WEATHER...
A COLD FRONT WILL BACK INTO THE EASTERN OKLAHOMA PANHANDLE AND
NORTHEAST TEXAS PANHANDLE ON THURSDAY...SETTING UP A SOUTHWEST TO
NORTHEAST TEMPERATURE GRADIENT ACROSS THE AREA. THIS FRONT WILL ALSO
KEEP WINDS LIGHTER...WITH SPEEDS EXPECTED TO REMAIN BELOW 15 MPH.
THUS...ELEVATED FIRE WEATHER CONDITIONS ARE NOT EXPECTED DESPITE
AFTERNOON RELATIVE HUMIDITIES FALLING TO 15 TO 20 PERCENT ACROSS THE
SOUTHWEST HALF OF THE PANHANDLES. UNSEASONABLY WARM TEMPERATURES WILL
CONTINUE INTO FRIDAY. WESTERLY WINDS WILL INCREASE AHEAD OF THE NEXT
COLD FRONT...WHICH IS EXPECTED TO MOVE THROUGH DURING THE AFTERNOON
OR EVENING HOURS. ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE
ACROSS THE SOUTHWEST HALF OF THE AREA...WITH CRITICAL CONDITIONS
POSSIBLE ACROSS THE SOUTHWEST AND SOUTH CENTRAL TEXAS PANHANDLE WHERE
WESTERLY WINDS WILL INCREASE TO 20 TO 30 MPH WITH HIGHER GUSTS AND
MINIMUM RELATIVE HUMIDITIES WILL FALL TO 15 TO 20 PERCENT. A FIRE
WEATHER WATCH HAS BEEN ISSUED FOR THESE AREAS. THERE IS STILL SOME
UNCERTAINTY REGARDING TIMING OF THE COLD FRONT...AND A FASTER ARRIVAL
COULD POTENTIALLY EASE FIRE WEATHER CONCERNS WHILE A SLOWER ARRIVAL
MAY ALLOW CRITICAL CONDITIONS TO DEVELOP OVER A LARGER AREA.
UNSEASONABLY WARM CONDITIONS WILL CONTINUE OVER THE WEEKEND INTO
MONDAY. COMBINED WITH BREEZY CONDITIONS...ELEVATED FIRE WEATHER
CONDITIONS WILL BE POSSIBLE SATURDAY THROUGH MONDAY ACROSS WESTERN
AND CENTRAL PORTIONS OF THE AREA.
KB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING
FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...DEAF SMITH...
OLDHAM...POTTER...RANDALL.
OK...NONE.
&&
$$
KS/JJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
916 PM CST FRI JAN 20 2012
.UPDATE...
LAKE EFFECT SNOW BAND HAS SET UP RIGHT ALONG RACINE/MILWAUKEE
COUNTY LINE. DELTA T VALUES ARE ABOUT 16. VAD WIND FROM KMKE TDWR
HAS NORTHEAST 925 MB WIND AT 15 KNOTS...BUT MOST GUIDANCE SHOWS 25
KNOTS OVER CENTRAL LAKE MICHIGAN. NICE CONVERGENCE SHOWN IN
SURFACE OBSERVATIONS WITH NORTHWEST WIND AND 12F AT KMKE WITH 23F
AND EAST WIND AT KRAC.
WRF NMM 4KM FROM NCEP SHOWS 0.45" OF LIQUID OVER EASTERN RACINE
COUNTY FROM 06Z TO 18Z SATURDAY. DECIDED TO GO WITH AMOUNTS
ROUGHLY HALF THAT AND COMPROMISE BETWEEN LOCAL 4KM WRF AND HRRR SO
ROUGHLY 2 TO 4 INCHES IN EASTERN RACINE AND KENOSHA COUNTIES AND
AN INCH OR TWO IN FAR SOUTHEAST MILWAUKEE COUNTY NEAR OAK CREEK
BEFORE THE BAND SHIFTS SLOWLY SOUTH ALONG THE LAKE SHORE. MAY HAVE
TO ADD MILWAUKEE COUNTY IF BAND DOES NOT SHIFT BUT FEEL THAT CITY
OF MILWAUKEE PROBABLY SAFE FROM ACCUMULATING SNOW.
&&
.AVIATION/06Z TAFS/...
LAKE EFFECT SNOW BAND HAS SET UP BETWEEN KMKE AND KENW TAF SITES.
SHOULD STAY SOUTH OF KMKE BUT CEILINGS ARE NOW IFR AND MAY PERSIST
FOR A WHILE UNTIL BAND SHIFTS FARTHER SOUTH. IFR VISIBILITIES IN
SNOW SHOWERS ALSO LIKELY EVENTUALLY AT KENW AS BAND SHIFTS SOUTH.
ELSEWHERE MVFR CEILINGS AT KUES SHOULD EVENTUALLY IMPROVE AND VFR
CEILINGS AT KMSN.
WINDS SHOULD BE LIGHT BUT MAY COME UP LATER SATURDAY NIGHT AND
THERE IS POTENTIAL FOR ADVECTION STRATUS BUT A BIT TOO LOW TO
MENTION IN TAFS AT THIS POINT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST SATURDAY FOR WIZ071-072.
LM...NONE.
&&
$$
UPDATE...CRAVEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 PM CST THU JAN 19 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
320 PM CST THU JAN 19 2012
MAIN FORECAST CONCERNS ARE ON THE ACCUMULATING SNOW EVENT FOR LATE
TONIGHT INTO FRIDAY...AS WELL AS A MIXED PRECIPITATION EVENT FOR
SUNDAY.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A WEST-NORTHWEST FLOW FROM THE PACIFIC NORTHWEST INTO THE
OHIO VALLEY WITH A TROUGH OVER THE WESTERN GREAT LAKES REGION.
ALSO NOTED ON WATER VAPOR IS A SHORTWAVE TROUGH JUST OFF THE COAST
OF OREGON. FAST JET STREAM IN THE WEST-NORTHWEST FLOW...WITH THE
RUC TROPOPAUSE WIND SPEEDS SHOWING 130-160KT FROM FAR SOUTHERN
SASKATCHEWAN INTO FAR WESTERN KENTUCKY. WITH THE FORECAST AREA ON
THE NORTHEAST/SUBSIDENT SIDE OF THE UPPER JET AND ON THE BACK SIDE
OF THE WESTERN GREAT LAKES TROUGH...HIGH PRESSURE IS FAVORED AT
THE SURFACE. THIS HIGH IS CENTERED OVER SOUTHERN MINNESOTA AND
IOWA. ARCTIC AIR REMAINS IN PLACE...NOTED BY SURFACE TEMPERATURES
ONLY JUST ABOVE ZERO...DESPITE PLENTY OF SUN. 12Z SOUNDING PLOT OF
850MB TEMPERATURES REFLECTIVE OF BOTH THE ARCTIC AIR AND THE FAST
UPPER JET...WITH READINGS OF -21 TO -25C AT ABR...MPX AND GRB
WHILE ONLY -9C AT OAX AND -12C AT DVN. A SIMILAR DRAMATIC
DIFFERENCE CAN BE SEEN IN PRECIPITABLE WATER PLOTS. ABR...MPX AND
GRB HAD READINGS OF 0.05 TO 0.1 INCHES OR 20-30 PERCENT OF
NORMAL...WHILE DVN AND OAX REPORTED 0.26 INCHES OR ALMOST 100
PERCENT OF NORMAL. LAST ITEM OF NOTE IS A FRONTOGENETIC BAND OF
SNOW OVER CENTRAL MONTANA. THIS AREA OF FRONTOGENESIS IS ALONG THE
WESTERN EXTENT OF THE AFOREMENTIONED SHARP CONTRAST IN
MOISTURE/850MB TEMPS.
TONIGHT AND FRIDAY...UPPER LEVEL FLOW IS PROGGED TO TURN MORE
WESTERLY/ZONAL DURING THE NEXT 24 HOURS...MOSTLY IN RESPONSE TO THE
TROUGH OFF THE OREGON COAST RAPIDLY MOVING INLAND. THIS TROUGH IS
VERY IMPORTANT TO THE FORECAST AND SPECIFICALLY HOW AMPLIFIED IT IS
AS IT MOVES THROUGH THE CENTRAL PLAINS ON FRIDAY. THE REASON IS THAT
AS THE DPVA AND WARM ADVECTION APPROACHES AHEAD OF THE TROUGH...THE
SHARP CONTRAST IN TEMPERATURES AND MOISTURE NOTED IN THE CURRENT
DISCUSSION WILL LIGHT UP WITH SNOW. ANOTHER FEATURE HELPING TO
PRODUCE THE SNOW WILL END UP BEING A RIGHT ENTRANCE REGION OF THE
CURRENT STRONG UPPER JET...WHICH LIFTS NORTHEAST TONIGHT AND FRIDAY
WITH THE CHANGE IN UPPER FLOW. THEREFORE...WHERE THIS SNOW BAND SETS
UP AND HOW STRONG DEPENDS ON THE AMPLITUDE OF THE TROUGH. RUN TO RUN
THE NAM HAS BEEN THE MOST POTENT WITH THIS TROUGH...THOUGH IT HAS
SPED UP SOME TO COME IN CLOSER WITH THE CONSENSUS WITH THE 19.12Z
RUN. THE CANADIAN HAS BEEN CONSISTENTLY SHOWING A LESS POTENT
TROUGH...KEEPING THE HEAVIER BAND MOSTLY SOUTH OF THE FORECAST
AREA...THOUGH THE LATEST 19.12Z RUN SHOWED A SLIGHT NORTHWARD DRIFT.
THE GFS REMAINS A CONSISTENT COMPROMISE APPROACH BETWEEN THE
CANADIAN AND NAM. ANOTHER ISSUE TO DEAL WITH REMAINS SNOW RATIOS. A
FLATTER SOLUTION ALLOWS FOR A SLOWER EXIT OF THE CURRENT ARCTIC
AIR...SETTING THE STAGE FOR A DEEPER DENDRTIC SNOW GROWTH LAYER.
THIS IS ESPECIALLY TRUE FOR ABOUT THE NORTHERN TWO THIRDS OF THE
FORECAST AREA...WHERE 20 TO 1 SNOW RATIOS ARE LIKELY...NO MATTER
WHAT SOLUTION IS FOLLOWED. ON THE OTHER HAND...THE MORE AMPLIFIED
SOLUTION LIKE THE NAM ADVECTS WARMER MID LEVEL AIR INTO THE
SOUTHERN THIRD OF THE FORECAST AREA...DECREASING THE DENDRITIC
GROWTH ZONE. AROUND 15 TO 1 RATIOS WOULD BE MORE REASONABLE IN
THIS ZONE. IN TERMS OF TIMING...GOOD CONSENSUS FOR THE SNOW TO
MOVE INTO AREAS WEST OF THE MISSISSIPPI RIVER BETWEEN
09-12Z...OVERSPREAD MUCH OF THE AREA FOR 12-18Z WHICH ALSO LOOKS
TO BE THE HEAVIEST SNOW TIME...THEN BEGIN TO EXIT WEST TO EAST
BETWEEN 18-00Z. TRICKY DETERMINING THE HAZARD SCENARIO WITH
QUESTIONS ON THE SNOW TO WATER RATIO AS WELL AS PLACEMENT OF THE
HEAVIER BAND. HIGH CERTAINTY THAT LOCATIONS ALONG AND SOUTH OF
I-90 WILL SEE ADVISORY CRITERIA. NOT ENOUGH CERTAINTY EXISTS TO
PLACE ANY WARNINGS...THOUGH...WITH THE UNCERTAINTY ON MAX QPF
PLACEMENT...FORCING AND SNOW TO WATER RATIOS. 19.15Z SREF PLUMES
ALSO SHOWS A LARGE AMOUNT OF UNCERTAINTY REGARDING AMOUNTS. FUTURE
SHIFTS MAY UPGRADE TO WARNINGS IF THE ZONE OF HEAVIEST QPF CAN BE
NARROWED DOWN. QUICKLY REGARDING TEMPERATURES...SHOULD SEE LOWS
THIS EVENING THEN READINGS RISE AFTER MIDNIGHT TONIGHT INTO FRIDAY
WITH THE CLOUDS/WARM ADVECTION MOVING IN.
FRIDAY NIGHT AND SATURDAY...SHORTWAVE TROUGH THAT MOVED INTO THE
CENTRAL PLAINS FRIDAY CONTINUES HEADING RAPIDLY OFF TO THE EAST
FRIDAY NIGHT...ALLOWING HIGH PRESSURE TO BUILD OVER THE ENTIRE
AREA BY SATURDAY MORNING. SKIES LOOK TO CLEAR AS THE HIGH MOVES
IN...THEREFORE...WITH THE FRESH SNOW WENT TOWARDS THE LOW END OF
GUIDANCE FOR LOWS. FOR SATURDAY...MODELS ARE IN GOOD AGREEMENT
BRINGING A DEEP TROUGH INTO THE WESTERN U.S. AS THIS OCCURS...
HEIGHTS BUILD DOWNSTREAM OVER THE FORECAST AREA...RESULTING IN
FAIRLY STRONG WARM ADVECTION BY THE END OF THE DAY. 850MB TEMPS
CLIMB FROM -8 TO -12C AT 12Z SATURDAY TO -2 TO -6C BY 00Z SUNDAY.
NOT ANTICIPATING ANY PRECIPITATION ON SATURDAY...DUE TO THE DRY
HIGH PRESSURE AREA STILL IN PLACE...THOUGH AN INCREASE OF MID AND
HIGH CLOUD COVER IS LIKELY AS THE DAY GOES ON. GENERALLY FOLLOWED
A BLEND OF GUIDANCE FOR HIGHS.
SATURDAY NIGHT AND SUNDAY...FOCUS OF ATTENTION IS ON THAT NEXT DEEP
TROUGH IN THE WESTERN U.S. AT 00Z SUNDAY. DPROG/DT OF ALL MODELS
SHOWS THIS TROUGH TRENDING RAPIDLY DEEPER AND SLOWING SOMEWHAT.
RIGHT NOW MOST MODELS ARE IN AGREEMENT OF THE TROUGH MOVING INTO THE
PLAINS ON SUNDAY. ALSO OF NOTE IS THAT A POTENT SHORTWAVE IS
INDICATED AT THE BOTTOM OF THE TROUGH...WHICH MAY TURN NEGATIVE TILT
AS IT LIFTS UP THE EAST SIDE OF THE TROUGH TOWARDS THE FORECAST AREA
LATE SUNDAY AND INTO SUNDAY NIGHT. THIS MEANS THE WEATHER IS GOING
TO BE ACTIVE AGAIN...BUT THIS TIME THE TROUGH HAS A SURGE OF WARM
AND MORE MOIST AIR FROM THE GULF OF MEXICO...RESULTING IN ISSUES
WITH PRECIPITATION TYPE. FIRST FOR SATURDAY NIGHT...WARM ADVECTION
DOWNSTREAM SHOULD ALLOW TEMPERATURES TO CLIMB THROUGH THE NIGHT.
ANY PRECIPITATION ASSOCIATED WITH THE WARM ADVECTION LOOKS TO STAY
OFF TO OUR NORTHWEST...MAINLY OVER WESTERN AND NORTHERN MINNESOTA.
BETTER SHOT FOR PRECIPITATION EXISTS ON SUNDAY...ESPECIALLY IN THE
AFTERNOON...AS HEIGHT FALLS FROM THE UPPER TROUGH AND ISENTROPIC
LIFT AHEAD OF THE TROUGH MOVES INTO THE AREA. WITH THE PERSISTENT
WARM ADVECTION...2 METER TEMPERATURES ARE LIKELY TO CLIMB ABOVE
FREEZING FOR MOST OF THE AREA...RESULTING IN POTENTIAL FOR A
MIX/CHANGE TO RAIN AND SNOW. WITH GROUND AND SNOW TEMPERATURES
PROBABLY STAYING BELOW FREEZING...THIS RAIN COULD TURN TO ICE ON
UNTREATED ROADS...THUS THE INTRODUCTION OF FREEZING RAIN TOO INTO
THE FORECAST. NOTE...THERE IS A MID LEVEL DRY AIR LAYER NOTED IN
SOUNDINGS...THOUGH IT DOES NOT LOOK TO BE DEEP ENOUGH OR DRY ENOUGH
AT THIS TIME TO PREVENT ICE FROM ALOFT REACHING DOWN TO THE SURFACE.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
320 PM CST THU JAN 19 2012
UPPER TROUGH OVER THE PLAINS LOOKS TO LIFT NORTHEAST THROUGH THE
AREA SUNDAY NIGHT AND AWAY FROM THE AREA ON MONDAY. CERTAINLY THIS
BEARS WATCHING FOR TIMING GIVEN THE TREND FOR THIS TROUGH TO BE
AMPLIFIED AND SLOWER. IN FACT THE NEW 19.12Z ECMWF SLOWED DOWN THE
TROUGH A BIT MORE. SHOULD SEE ANY RAIN/FREEZING RAIN CHANGE OVER TO
SNOW THROUGH THE NIGHT SUNDAY NIGHT...WITH ALL SNOW MONDAY...THOUGH
AGAIN THE PRECIPITATION SHOULD BE WINDING DOWN MONDAY. MAY HAVE TO
WATCH FOR POTENTIAL ADVISORY SNOW SUNDAY NIGHT...AND POSSIBLY INTO
MONDAY IF THE NEW ECMWF IS CORRECT.
REST OF NEXT WEEK CONTINUES TO SHOW A SOMEWHAT ACTIVE PATTERN...WITH
MODELS IN VERY GOOD AGREEMENT SHOWING SHORTWAVE TROUGHS MOVING
THROUGH TUESDAY NIGHT INTO WEDNESDAY...AS WELL AS ON THURSDAY.
HOWEVER...NONE OF THESE TROUGHS LOOK TO HAVE A LOT OF MOISTURE WITH
THEM...LIKELY SHUNTED OFF BY THE DEEPER SUNDAY NIGHT/MONDAY TROUGH.
FOLLOWED A CONSENSUS APPROACH GIVEN THE GOOD AGREEMENT...RESULTING
IN MOSTLY 20-40 PERCENT CHANCES FOR THESE TROUGHS. TEMPERATURES WILL
BE WARMER NEXT WEEK THAN THIS WEEK...THANKS TO THE MAIN POLAR
WESTERLIES SHIFTING WELL NORTH INTO CANADA. IT DOES NOT APPEAR THAT
ENOUGH WARM AIR ENTERS ANY OF THE TROUGHS TO RESULT IN LIQUID
PRECIPITATION...THOUGH.
&&
.AVIATION...THROUGH 18Z FRIDAY
1134 AM CST THU JAN 19 2012
SHORT WAVE TROUGH COMING ON TO THE PACIFIC NORTHWEST COAST WILL
QUICKLY MOVE ACROSS THE ROCKIES AND INTO THE MIDWEST BY LATE
TONIGHT. THE 19.12Z NAM AND GFS ARE BOTH IN AGREEMENT THAT THE
WAVE WILL BE MOVING RAPIDLY WITH LITTLE CHANCE FOR AMPLIFICATION
AS IT COMES THROUGH WITH A POSITIVE TILT. THIS WILL BRING A NARROW
AND QUICK SHOT OF 12 TO 16 PVU/S OF PV ADVECTION IN THE 500-300 MB
LAYER FRIDAY MORNING. THERE WILL BE SOME WEAK TO MODERATE
FRONTOGENESIS THAT SETS UP IN THE 850-500 MB LAYER FOR FRIDAY
MORNING AND COMBINED WITH 2 TO 4 UBAR/S OF UP GLIDE ON THE 280
THROUGH 290K ISENTROPIC SURFACES...THERE WILL BE ENOUGH FORCING
TO PRODUCE A PERIOD OF SNOW FOR BOTH TAF SITES. VFR CONDITIONS
WILL PREVAIL UNTIL THE SNOW STARTS AND SHOULD THEN SEE AN ABRUPT
DROP TO IFR FOR BOTH THE VISIBILITY AND CEILINGS. FORCING COULD BE
STRONG ENOUGH TO PRODUCE A 3 TO 4 HOUR PERIOD OF VISIBILITIES DOWN
TO ABOUT A MILE WITH SUB 1000 FOOT CEILINGS. EXPECTING THE SNOW
TO START IN THE 10 TO 12Z TIME FRAME WITH THE WORST CONDITIONS
EXPECTED A COUPLE OF HOURS AFTER THE SNOW INITIALLY BEGINS.
APPEARS AS FAST THE SNOW COMES IN...IT WILL ALSO END...BUT THIS IS
NOT EXPECTED TO OCCUR UNTIL AFTER 18Z FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 PM CST THU JAN 19 2012
WI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR
WIZ041>044-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
MNZ086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 AM CST SAT JAN 21 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
//PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS LINGERING THROUGH THE MORNING.
* POTENTIAL FOR LIGHT LAKE EFFECT SNOW SHOWERS AFT 10Z FOR A FEW
HOURS.
* IMPROVEMENT TO VFR EXPECTED THIS AFTERNOON.
* NORTH-NORTHEAST WINDS BECOMING EAST-SOUTHEAST THIS
AFTERNOON.
MDB
//DISCUSSION...UPDATED 09Z...
CONTINUING TO WATCH BAND OF LIGHT LAKE EFFECT SNOW MOVE SOUTHWARD
INTO LAKE COUNTY ILLINOIS. HAVE NOT SEEN MUCH IN THE WAY OF VSBY
REDUCTION SO FAR AND EXPECT ANY REDUCTION TO BE SHORT LIVED.
CONVERGENCE ALONG THE IL SHORE CONTINUES TO PLAY A BIT OF HAVOC
WITH WINDS. SEEING FLUCTUATIONS BETWEEN NORTH AND NORTHEAST WITH
SPEEDS UP AROUND 10 KT THOUGH A FEW GUSTS INTO THE 16-20 KT RANGE
HAVE OCCURRED. THINK THAT WINDOW FOR GUSTS WILL BE CONFINED TO THE
NEXT FEW HOURS BEFORE SPEEDS DIMINISH SLIGHTLY AS HIGH PRESSURE
ARRIVES AND CONVERGENCE ALONG THE LAKE WEAKENS.
MDB
FROM 06Z...
MID-LEVEL DISTURBANCE RESPONSIBLE FOR FRIDAYS SNOW IS MOVING
ACROSS THE FORECAST AREA AT ISSUANCE TIME...WITH SNOW ALREADY
HAVING ENDED RAPIDLY FROM WEST TO EAST ACROSS THE TERMINALS.
PATCHY MVFR CEILINGS REMAIN HOWEVER...GENERALLY IN THE 1200-1800
FOOT RANGE ACROSS NORTHERN IL AT 04Z. A PLACES HAVE SCATTERED OUT
TO VFR BRIEFLY...BUT LOW LEVEL NORTH/NORTHEAST WINDS OFF THE LAKE
AND SOUTHEAST WISCONSIN SHOULD HELP TO MAINTAIN A PREVAILING MVFR
CIG THROUGH THE NIGHT. WITH SNOW ASSOCIATED WITH LARGE SCALE
SYSTEM MOVING OFF TO THE EAST...RADAR IS NOW ABLE TO BETTER DEPICT
WEAK BAND OF LIGHT LAKE EFFECT SNOW WHICH HAS BEEN PERSISTENT
ALONG CONVERGENCE ZONE/TROUGH IN LOW LEVEL WINDS. THIS LIGHT SNOW
IS CURRENTLY AFFECTING MAINLY FAR SOUTHEAST WI FROM MKE SOUTH TO
RAC/ENW...BUT HIGH RES MODELS CONTINUE TO INDICATE THAT THIS WILL
SHIFT SOUTH ACROSS LAKE/COOK COUNTIES LATER TONIGHT AND LINGER
SATURDAY MORNING BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE
AFTERNOON. FORECAST SOUNDINGS DEPICT FAIRLY HEALTHY INVERSION ALOFT
WHICH LOOKS TO PREVENT MUCH IN THE WAY OF DEEP LAKE-INDUCED
CONVECTION FROM DEVELOPING...BUT A PERIOD OF PESKY LIGHT SNOW/SNOW
SHOWERS APPEARS LIKELY DURING THE ROUGHLY 10-15Z PERIOD INTO ORD.
ONCE LOW LEVEL FLOW BECOMES MORE EASTERLY/SOUTHEASTERLY SATURDAY
AFTERNOON...MVFR CIGS SHOULD CONTINUE TO RISE AND SCATTER...WITH
VFR CONDITIONS EXPECTED DURING THE LATE AFTERNOON/EARLY EVENING.
MODELS SUGGEST MVFR CIG AROUND 2500 FT MAY DEVELOP LATER SATURDAY
EVENING AS WARM ADVECTION DEVELOPS AHEAD OF THE NEXT APPROACHING
UPPER TROUGH.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIG TRENDS THROUGH THE MORNING.
* MEDIUM CONFIDENCE IN LAKE EFFECT SNOW SHOWERS...THOUGH LOW
CONFIDENCE IN EXACT PLACEMENT OF NARROW BAND AND DETAILS OF
RELATED CIG/VIS.
* MEDIUM-HIGH CONFIDENCE IN WIND TREND.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
252 AM CST
HIGH PRESSURE WILL SPREAD ACROSS LAKE MICHIGAN TODAY BUT THE WEAK
LARGER SCALE FLOW WILL CONTINUE TO SUPPORT LAKE INFLUENCED
WINDS...ESPECIALLY ACROSS THE SOUTHERN PART OF THE LAKE. AN
AREA OF CONVERGENCE CONTINUES TO MOVE DOWN THE WESTERN SHORE
TOWARD THE IL/WI BORDER WITH NORTHWEST WINDS TO THE WEST AND EAST
TO NORTHEAST WINDS TO THE EAST OF THIS BOUNDARY. SPEEDS ARE
GENERALLY IN THE 10-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE BUT
SHOULD FALL OFF AS THE CONVERGENCE WEAKENS THROUGH LATE
MORNING/EARLY AFTERNOON. OTHERWISE WINDS WILL BECOME VARIABLE
ACROSS MUCH OF THE LAKE THIS AFTERNOON AS THE HIGH ARRIVES. WINDS
WILL THEN TURN SOUTHERLY INTO THIS EVENING WITH SPEEDS STEADILY
PICKING UP FROM SOUTH TO NORTH. IT APPEARS THAT LOW END GALES WILL
BE POSSIBLE LATE TONIGHT AND CONTINUE THROUGH MUCH OF SUNDAY.
SURFACE LOW PRESSURE NOW BUILDING INTO THE HIGH PLAINS WILL
CONSOLIDATE TO THE WEST OR SOUTHWEST AND THEN MOVE NORTH-
NORTHEASTWARD UP LAKE MICHIGAN SUNDAY NIGHT AND MONDAY MORNING.
THIS MAY RESULT IN A BRIEF EASING OF THE WINDS SUNDAY EVENING BUT
THIS TIMING IS SUBJECT TO CHANGE BASED ON THE SPEED OF THE LOW.
WINDS WILL THEN SHIFT TO THE SOUTHWEST AND WEST MONDAY WITH GALES
RETURNING...ESPECIALLY SOUTH...THAT IS IF SPEEDS EASE BELOW GALES
AS THE LOW MOVES OVER THE LAKE. WILL KEEP THE GALE WATCH GOING
THROUGH SUNDAY EVENING BUT IT MAY NEED TO BE EXTENDED RIGHT
THROUGH MONDAY AND MONDAY NIGHT. HIGH PRESSURE WILL BUILD BACK
ACROSS THE LAKE TUESDAY ALLOWING WINDS TO DIMINISH. THE REST OF
THE WEEK LOOKS ACTIVE WITH A SERIES OF LOWS EXPECTED TO PASS NORTH
OF THE LAKE RESULTING IN PERIODIC WIND SHIFTS AS EACH ASSOCIATED
TROUGH AXIS PASSES WITH AN INCREASE IN WINDS SPEED AS THIS OCCURS
AS WELL. TOO EARLY TO TELL IF SHORT PERIODS OF GALES WILL
MATERIALIZE BUT IT IS A POSSIBILITY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1048 PM CST FRI JAN 20 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
//PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS LINGERING OVERNIGHT AND SATURDAY MORNING.
* POTENTIAL FOR LIGHT LAKE EFFECT SNOW SHOWERS TOWARD MORNING.
* IMPROVEMENT TO VFR EXPECTED SATURDAY AFTERNOON.
* NORTH-NORTHEAST WINDS BECOMING EAST-SOUTHEAST SATURDAY
AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
MID-LEVEL DISTURBANCE RESPONSIBLE FOR FRIDAYS SNOW IS MOVING
ACROSS THE FORECAST AREA AT ISSUANCE TIME...WITH SNOW ALREADY
HAVING ENDED RAPIDLY FROM WEST TO EAST ACROSS THE TERMINALS.
PATCHY MVFR CEILINGS REMAIN HOWEVER...GENERALLY IN THE 1200-1800
FOOT RANGE ACROSS NORTHERN IL AT 04Z. A PLACES HAVE SCATTERED OUT
TO VFR BRIEFLY...BUT LOW LEVEL NORTH/NORTHEAST WINDS OFF THE LAKE
AND SOUTHEAST WISCONSIN SHOULD HELP TO MAINTAIN A PREVAILING MVFR
CIG THROUGH THE NIGHT. WITH SNOW ASSOCIATED WITH LARGE SCALE
SYSTEM MOVING OFF TO THE EAST...RADAR IS NOW ABLE TO BETTER DEPICT
WEAK BAND OF LIGHT LAKE EFFECT SNOW WHICH HAS BEEN PERSISTENT
ALONG CONVERGENCE ZONE/TROUGH IN LOW LEVEL WINDS. THIS LIGHT SNOW
IS CURRENTLY AFFECTING MAINLY FAR SOUTHEAST WI FROM MKE SOUTH TO
RAC/ENW...BUT HIGH RES MODELS CONTINUE TO INDICATE THAT THIS WILL
SHIFT SOUTH ACROSS LAKE/COOK COUNTIES LATER TONIGHT AND LINGER
SATURDAY MORNING BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE
AFTERNOON. FORECAST SOUNDINGS DEPICT FAIRLY HEALTHY INVERSION ALOFT
WHICH LOOKS TO PREVENT MUCH IN THE WAY OF DEEP LAKE-INDUCED
CONVECTION FROM DEVELOPING...BUT A PERIOD OF PESKY LIGHT SNOW/SNOW
SHOWERS APPEARS LIKELY DURING THE ROUGHLY 10-15Z PERIOD INTO ORD.
ONCE LOW LEVEL FLOW BECOMES MORE EASTERLY/SOUTHEASTERLY SATURDAY
AFTERNOON...MVFR CIGS SHOULD CONTINUE TO RISE AND SCATTER...WITH
VFR CONDITIONS EXPECTED DURING THE LATE AFTERNOON/EARLY EVENING.
MODELS SUGGEST MVFR CIG AROUND 2500 FT MAY DEVELOP LATER SATURDAY
EVENING AS WARM ADVECTION DEVELOPS AHEAD OF THE NEXT APPROACHING
UPPER TROUGH.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIG TRENDS THROUGH SATURDAY
MORNING.
* MEDIUM CONFIDENCE IN LAKE EFFECT SNOW SHOWERS...THOUGH LOW
CONFIDENCE IN EXACT PLACEMENT OF NARROW BAND AND DETAILS OF
RELATED CIG/VIS.
* MEDIUM-HIGH CONFIDENCE IN WIND TREND.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1228 AM EST SAT JAN 21 2012
.AVIATION...
BACK EDGE OF AREA OF SNOW MOVG EAST ACROSS NRN INDIANA ATTM AND SHOULD
CLEAR FWA IN NEXT COUPLE OF HOURS WITH VFR CONDITIONS UPSTREAM
OVER SW MI/NW INDIANA FOLLOWING THE END OF THE SNOW OVERNIGHT. VFR
CONDITIONS SHOULD PERSIST DURING THE DAY AND INTO TONIGHT AS HIGH
PRESSURE RIDGE MOVES ACROSS THE AREA.
&&
.PREV DISCUSSION...
UPDATE...
SNOW EVENT EVOLVING AS EXPECTED SO FAR. UPSTREAM REPORTS IN NORTHERN
IL INDICATE EXPECTED POTENTIAL FOR SOME AMOUNTS NEAR OR JUST ABOVE 6
INCHES. CURRENT ADVISORY HAS THIS WELL IN HAND WITH WORDING SO
CURRENTLY NO PLANS TO UPGRADE HEADLINES UNLESS WE START GETTING
WIDESPREAD REPORTS IN EXCESS OF 6 TO 7 INCHES LATER THIS EVENING
WITH ADDITIONAL SNOWFALL EXPECTED. MOST REPORTS SO FAR IN THE 1 TO 3
INCH RANGE WITH A FEW EXCEPTIONS. VISIBILITIES BEGINNING TO RISE
SLOWLY NEAR AND WEST OF CHICAGO SO EXPECT OUR WESTERN AREAS TO SEE
THIS MODERATE TO BRIEFLY HEAVY SNOW FOR A FEW MORE HOURS BEFORE
SNOWFALL RATES GRADUALLY DECREASE THERE WITH PROGRESSION EAST
THROUGH THE LATE EVENING AND OVERNIGHT HOURS. HIGH RES GUIDANCE ALSO
SHOWING THIS WITH HRRR LOOKING VERY GOOD SO FAR.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
MAIN FORECAST FOCUS WILL CONTINUE TO CENTER ON SIGNIFICANT SNOW
ACCUMULATIONS TONIGHT. A WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT FOR THE ENTIRE FORECAST AREA THROUGH 12Z SATURDAY.
A ZONE OF STRONG ISENTROPIC UPGLIDE PER RUC/GFS 290K SFC WILL
CONTINUE TO LIFT NORTHEAST ACROSS NORTHERN PORTIONS OF THE FORECAST
AREA. SEVERAL REPORTS NOW OF 1/2 TO 1/4 MILE VSBYS ACROSS NORTHERN
ILLINOIS AND STRONGEST ISENTROPIC ASCENT SHOULD SHIFT EASTWARD
ACROSS NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN IN THE 22Z-03Z
TIMEFRAME. DURING THIS PERIOD OF STRONGER FORCING...STRONGEST UPWARD
VERTICAL MOTION SHOULD BE SOLIDLY ENCOMPASSED IN FAVORABLE DENDRITIC
GROWTH ZONE. THUS...SHOULD SEE A PERIOD EARLY THIS EVENING WHERE
SNOW TO LIQUID RATIOS INCREASE SHARPLY FOR A TIME. ISENTROPIC PROGS
HAVE ALSO SUGGESTED PERHAPS A SLIGHT WEAKENING OF THE ISENTROPIC
LIFT THIS EVENING AS VORT MAX SKIRTING ACROSS SOUTHERN WISCONSIN
THIS AFTERNOON BECOMES MORE SHEARED ACROSS THE SOUTHERN LAKES.
NONETHELESS...A 2 TO 4 PERIOD OF SNOWFALL RATES AROUND AN INCH PER
HOUR APPEARS TO BE POSSIBLE LATE THIS AFTERNOON/EARLY THIS EVENING
FOR AREAS ESPECIALLY ALONG AND NORTH OF THE ROUTE 30 CORRIDOR.
ACCUMULATIONS WILL BE IN SOMEWHAT MORE QUESTION ACROSS THE SOUTH AS
THIS BAND SHOULD PROVIDE GREAT IMPACTS ACROSS THE NORTHERN HALF.
WATER VAPOR IMAGERY CONTINUES TO INDICATE A STRONGER VORT MAX
DROPPING INTO THE CENTRAL PLAINS THAT WILL BEGIN TO SHIFT EASTWARD
INTO THE MID MS RVR VALLEY LATER THIS EVENING. SHOULD START TO SEE A
MORE FRONTALLY FORCED AREA OF SNOW DEVELOP EXTENDING SOUTHWEST FROM
THIS INITIALLY WEST TO EAST ORIENTED BAND THAT WILL AFFECT
CENTRAL/SOUTHERN AREAS LATE THIS EVENING. STILL EXPECTING STORM
TOTAL SNOWFALL AMOUNTS IN THE 4 TO 7 RANGE CENTRAL AND NORTH...WITH
AMOUNTS IN THE 2 TO 4 RANGE FAR SOUTH. GFS/RUC VERTICAL CROSS
SECTIONS ALSO INDICATE INCREASING INSTABILITY ALOFT (NEGATIVE EPV)
LIFTING ACROSS EASTERN SECTIONS OF THE AREA LATE THIS EVENING AS
SOUTHWESTERLY FLOW STRENGTHENS IN ADVANCE OF THIS SECONDARY SHORT
WAVE. THIS INCREASE IN INSTABILITY ALOFT SHOULD CORRESPOND TO THIS
SECONDARY MID LEVEL FORCING MAX WITH THIS SHORT WAVE...SO HAVE
KEPT AMOUNTS MORE SOLIDLY IN THE ADVISORY RANGE IN THE FAR
SOUTHEAST...WITH SLIGHTLY LESSER TOTALS IN THE SOUTHWEST.
CURRENTLY HAVE DRAWN UP TOTAL ACCUMULATIONS JUST BELOW ADVISORY
CRITERIA ACROSS THE SOUTHWEST BUT DUE TO COMPLICATING MESOSCALE
FORCING MECHANISMS MENTIONED...WILL MAINTAIN ALL HEADLINES AT THIS
TIME.
CONDITIONS TO IMPROVE FROM WEST TO EAST OVERNIGHT WITH THE PASSAGE
OF THIS SECONDARY VORT MAX. ORIENTATION OF RIDGE AXIS TO THE WEST
SHOULD SUPPORT ANY LAKE EFFECT SNOW SHOWERS WEST OF THE LOCAL
FORECAST AREA INTO NORTHWEST INDIANA/NORTHEAST ILLINOIS. SATURDAY
SHOULD FEATURE QUIET WEATHER WITH SFC HIGH BEGINNING TO BUILD IN.
WEAK LOW LEVEL EASTERLIES AND NEW SNOW COVER SHOULD PROMOTE WEAK
MIXING AND HAVE UNDERCUT MOST AVAILABLE GUIDANCE FOR HIGH TEMPS.
LONG TERM...
SUNDAY THROUGH FRIDAY
MID LEVEL FLOW TRANSITION STILL ON TRACK IN THE PERIOD GIVEN THE
RETURN OF ALASKA TROUGHING...WITH MUCH MILDER PAC ORIGIN DOWNSLOPE
FLOW EXPECTED INTO THE REGION BY EARLY NEXT WEEK. A DEEP LONGWAVE
TROUGH IS STILL EXPECTED IN THE SUN NIGHT-MON PERIOD...SUPPORTING
ROBUST LL FLOW FIELDS WITH SIG THETA-E ADVECTION INTO THE AREA.
SPLIT FLOW REGIME WILL FOLLOW WITH STRONG MODEL/ENSEMBLE SUPPORT
CONTINUING. FAST PERTURBED WNW FLOW WILL OFFER LOW CONFIDENCE PER
DISTURBANCE TIMING IN THE LATE PERIODS GIVEN TYPICAL POOR MODEL
PERFORMANCE PER THESE FEATURES. HENCE...NO SIG CHANGE PER PRECIP
CHANCE WED-FRI...WITH PREFERENCE TOWARD 24-36 HOUR FORECAST WINDOWS
PER PRECIP CHANCES GIVEN INHERENT VARIABILITY PER IMPULSE TIMING.
SUN-MON...SIG MID LEVEL TROUGH IS STILL ON TRACK TO DIG INTO THE SW
CONUS AND BEGIN TO EJECT TOWARD THE REGION. ECMWF/GEM/UKMET ARE
PREFERRED GIVEN THEIR HANDLING OF THE DIGGING MID LEVEL TROUGH WITH
NEGATIVE TILT CHARACTERISTICS. CERTAINLY DONT BUY THE NAM/S OUTLIER
NORTH BIAS PER THE SFC CYCLONE AND THE GFS/S WILD VARIABILITY PER
TROUGH DEPTH/TIMING/AND TRACK. CONTINUED MODEL SUPPORT FOR A STRONG
SOUTHERN PERIPHERY UPPER JET STREAK AND NEGATIVE UPPER TROUGH TILT
SUGGESTS A WEST BIAS TO THE SFC LOW TRACK WITH SLOWER SYSTEM ARRIVAL
AND HAVE CONTINUED THIS IN THE GRIDS. SYSTEM INFLUENCE TO THE LOCAL
AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY FLOW
INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC ZONE
IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE EJECTING MID
LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE FALLS...SUPPORTING
RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL THETA-E ADV TO ENSUE
LATE SUNDAY IN THE REGION WITH SIG SFC LAYER DEWPOINT RISES BY
SUNDAY NIGHT. STAUNCH LL FLOW WITH A 60 TO 70 KNOT LLJ PROGGED IN
THE ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT DEEP LAYER THETA-E
RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A SATURATED BL WITH
DRIZZLE AND FOG EXPECTED TO DEVELOP LATE SUNDAY AFTERNOON /AT THE
EARLIEST/ INTO THE EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT.
ECMWF H7-H3 LAYER ANALYSIS CONTINUES TO INDICATE AN INTACT EML WITH
STEEP MID LEVEL LAPSE RATES GIVEN STRONG LOW CENTERED WAA. H85
THETA-E APPROACHES 325K BY LATE SUNDAY NIGHT...WITH SW INDICES
NEGATIVE...INDICATING A GOOD ENVIRONMENT FOR ELEVATED THUNDERSTORMS.
HAVE MAINTAINED A LOW CHANCE THUNDER AT THIS POINT. ALBEIT
SMALL...THERE REMAINS A SMALL CONCERN FOR SEVERE WEATHER GIVEN
INDICATED H5 JETLET IN EXCESS OF 85 KNOTS...WHICH WOULD BE CAPABLE
OF SUPPORTING A QLCS JET DRIVEN THIN LINE. CONCERNS FOR INCREASED
FLOODING CONTINUE GIVEN FULL SNOWPACK MELT WITH THE POTENTIAL FOR
HEAVY RAIN. IN ADDITION...A SLOWER TROUGH ARRIVAL PER NEGATIVE
TROUGH TENDENCIES WOULD SUPPORT HIGHS INTO THE 50S AKIN TO ECMWF
PROGS. CAA WILL DOMINATE MONDAY WITH FALLING TEMPS IN THE DAYTIME
PERIOD LIKELY. LINGERING LIGHT SNOW SHOWERS WILL BE POSSIBLE.
TUE-FRI...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED-THUR PERIOD AND HAVE RETAINED POPS THEN...OPTING
TO KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS. HAVE ALSO
EXTENDED THIS MENTION INTO FRIDAY MAINLY PER COLLAB WITH SURROUNDING
OFFICES...WHICH ALSO FITS THE ACTIVE PATTERN. OTHERWISE...ADJUSTED
TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY ONCE AGAIN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING
FOR INZ003>009-012>018-020-022>027-032>034.
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR
MIZ077>081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR OHZ001-
002-004-005-015-016-024-025.
LM...NONE.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...JT
UPDATE...LASHLEY
AREA FORECAST DISCUSSION
NWS TOPEKA KS
321 AM CST SAT JAN 21 2012
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
SATELLITE SHOWS AREA OF STRATUS OVER SOUTHWESTERN IA MAKING STEADY
PROGRESS TO THE SOUTH. THE LATEST RUC AND NAM DO NOT HAVE THE
GREATEST HANDEL ON THIS IN THEIR RH PROGS. SO THINK BASED ON
ADVECTION ONLY THAT THE STRATUS WILL MAKE A RUN AT TOP AND FOE. AM A
LITTLE CONCERNED WITH THE 925 WINDS PROGGED TO VEER TO THE EAST THAT
THE STRATUS MAY BE STUBBORN TO MIX OUT UNTIL THE SFC RIDGE AXIS
PASSES TO THE EAST. INITIALLY THE CIGS MAY COME IN AT 2500 FT BUT
BASED ON OBS UPSTREAM THINK THIS WILL BE TEMPORARY WITH CIGS LIFTING
TO 3 KFT OR BETTER. DO NOT HAVE ENOUGH CONFIDENCE IN THEM MAKING IT
TO MHK TO INCLUDE IT THERE AT THIS TIME. THE SFC RIDGE AXIS SHOULD
PASS TO THE EAST AROUND 18Z WITH VFR CONDITIONS EXPECTED TO PERSIST
AND A SOUTHEASTERLY WIND FRESHENING.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1052 PM CST FRI JAN 20 2012
...AVIATION UPDATE...
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
SATELLITE SHOWS AREA OF STRATUS OVER SOUTHWESTERN IA MAKING STEADY
PROGRESS TO THE SOUTH. THE LATEST RUC AND NAM DO NOT HAVE THE
GREATEST HANDEL ON THIS IN THEIR RH PROGS. SO THINK BASED ON
ADVECTION ONLY THAT THE STRATUS WILL MAKE A RUN AT TOP AND FOE. AM A
LITTLE CONCERNED WITH THE 925 WINDS PROGGED TO VEER TO THE EAST THAT
THE STRATUS MAY BE STUBBORN TO MIX OUT UNTIL THE SFC RIDGE AXIS
PASSES TO THE EAST. INITIALLY THE CIGS MAY COME IN AT 2500 FT BUT
BASED ON OBS UPSTREAM THINK THIS WILL BE TEMPORARY WITH CIGS LIFTING
TO 3 KFT OR BETTER. DO NOT HAVE ENOUGH CONFIDENCE IN THEM MAKING IT
TO MHK TO INCLUDE IT THERE AT THIS TIME. THE SFC RIDGE AXIS SHOULD
PASS TO THE EAST AROUND 18Z WITH VFR CONDITIONS EXPECTED TO PERSIST
AND A SOUTHEASTERLY WIND FRESHENING.
WOLTERS
&&
.PREV DISCUSSION... /330 PM CST FRI JAN 20 2012/
THROUGH SATURDAY...AN UPPER LEVEL DISTURBANCE WAS CROSSING THE
NORTHERN PLAINS INTO THE GREAT LAKES REGION THIS AFTERNOON WITH SNOW
WELL NORTH OF THE FORECAST AREA. SURFACE LOW PRESSURE WAS SITUATED
IN THE RED RIVER VALLEY WITH BROAD ISENTROPIC UPSLOPE FLOW PRODUCING
A LOW STRATUS CLOUD DECK FROM NORTHEAST OKLAHOMA INTO EASTERN KANSAS
AND POINTS EAST. THESE LOW CLOUDS COMBINED WITH WIDESPREAD HIGH
CLOUDS... SURFACE COLD ADVECTION AND SNOW COVER IN PARTS OF THE AREA
TO KEEP HIGH TEMPS IN THE UPPER 20S AND LOWER 30S TODAY.
HIGH PRESSURE WILL BUILD IN TO NORTHERN KANSAS BY MORNING WITH WINDS
DECREASING FROM NORTHWEST TO SOUTHEAST AFTER MIDNIGHT. SKIES WILL
ALSO CLEAR OUT AND TEMPERATURES WILL FALL QUICKLY AS SOON AS THE
WINDS DIMINISH. EXPECT THE COLDEST TEMPS TO BE IN AREAS WITH SNOW
COVER WHERE LOWS COULD APPROACH 0 DEGREES WHILE EAST CENTRAL KANSAS
WILL PROBABLY REMAIN IN THE TEENS AS WINDS ARE EXPECTED TO KEEP
THINGS MIXED THROUGH SUNRISE.
THE NEXT UPPER LEVEL SYSTEM WILL MOVE OUT INTO THE ROCKIES BY LATE
SATURDAY WITH LEE CYCLOGENESIS IN EASTERN COLORADO. SOUTHERLY RETURN
FLOW WILL KICK UP ACROSS KANSAS WITH A BIT OF WARM ADVECTION AS
WELL. TEMPS WILL WARM TO NEAR FREEZING OR A BIT WARMER IN ANY AREAS
FREE OF SNOW COVER BUT IT WILL STILL FEEL CHILLY WITH THE BREEZE.
BARJENBRUCH
SUNDAY THROUGH FRIDAY...STRONG WARM AIR ADVECTION STARTS UP ON
SUNDAY AS SOUTHERLY FLOW IN RESPONSE TO A DEEPENING SURFACE TROUGH
MOVES INTO THE AREA. EXPECT A FAIRLY SIGNIFICANT JUMP IN
TEMPERATURES FROM SATURDAY TO SUNDAY...AS HIGHS ON SUNDAY COULD
REACH INTO THE LOWER 50S...ESPECIALLY SOUTH AND EAST OF THE
TURNPIKE. AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY REACH
INTO THE MID TO UPPER 40S. ALTHOUGH THERE WILL BE SOME ISENTROPIC
LIFT ASSOCIATED WITH THE STRONG WARM AIR ADVECTION MARGINAL MOISTURE
RETURN AS INDICATED BY CONDENSATION PRESSURE DEFICITS WELL ABOVE 100
MB ON ALL ANALYZED ISENTROPIC SURFACES WILL PRECLUDE WARM AIR
ADVECTION SHOWERS ON SUNDAY MORNING. AS THE PARENT UPPER TROUGH DIGS
SOUTHWARD ENOUGH FORCING FOR ASCENT WILL BE PRESENT ALONG THE
LEADING 500 MB VORTICITY MAXIMUM THAT PRECIPITATION SHOULD COMMENCE
ACROSS THE AREA AROUND 18Z ON SUNDAY...MAINLY IN NORTH CENTRAL
KANSAS. PRECIP WILL SPREAD EASTWARD THROUGHOUT THE REST OF THE
AFTERNOON ON SUNDAY...STARTING MAINLY AS RAIN...THEN SWITCHING OVER
TO A RAIN/SNOW MIXTURE. THERMAL PROFILES INDICATE THAT NORTHEAST
KANSAS COULD SEE A BRIEF WINDOW WHERE SNOWFALL COULD OCCUR...HOWEVER
GIVEN THE MARGINAL SIGNALS FOR SNOW IN THE FORECAST SOUNDINGS WILL
CARRY A MIXTURE OF RAIN/SNOW MIX IN THE FORECAST FOR SUNDAY EVENING.
COLDER AIR MORE CONDUCIVE TO PURE SNOW FORMATION WILL MOVE INTO FAR
NORTHEAST KANSAS BY SUNDAY NIGHT LIKELY BRINGING A PERIOD OF PURE
SNOW TO AREAS NORTH OF INTERSTATE 70 ON WEDNESDAY NIGHT. EXPECT THE
UPPER TROUGH TO MOVE OUT OF THE AREA BY MONDAY MORNING WHICH WILL
CAUSE PRECIP TO COME TO AN END BY EARLY MONDAY MORNING.
EXPECT MILD CONDITIONS TO PERSIST AFTER THE RAIN/SNOW ENDS ON
SUNDAY...AS SHORTWAVE RIDGING MOVES INTO THE AREA FOR THE BEGINNING
TO MIDDLE PART OF THE WORK WEEK. THE NEXT CHANCE FOR PRECIP LOOKS TO
TAKE SHAPE TUESDAY NIGHT INTO WEDNESDAY MORNING AS STRONG WARM/MOIST
AIR ADVECTION PUSHES INTO THE AREA AHEAD OF THE NEXT UPPER TROUGH.
INTRODUCED PRECIP FOR LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
LASTING ROUGHLY THROUGH WEDNESDAY AFTERNOON. ONCE AGAIN THERMAL
PROFILES INDICATE A MARGINAL PRECIP TYPE EVENT...MEANING A RAIN/SNOW
MIXTURE IS EXPECTED FROM THIS EVENT ON TUESDAY/WEDNESDAY. EVEN
THOUGH PRECIP IS EXPECTED THROUGH TUESDAY AND WEDNESDAY EXPECT HIGHS
ALL WEEK TO REACH THE MID 40S TO POSSIBLY EVEN LOWER 50S.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1049 PM MST FRI JAN 20 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
NO APPARENT PRECIPITATION UPSTREAM AND THE HRRR MODEL KEEPS OUR
AREA DRY TONIGHT...SO REMOVED POPS FROM MOST OF THE AREA...EXCEPT A
SLIGHT CHANCE STRIP ALONG THE INTERNATIONAL BORDER. HOWEVER
TEMPERATURES UPSTREAM HAVE WARMED CONSIDERABLY. THE NAM12 MODEL
WAS USED FOR THE DIURNAL TRENDS FOR TONIGHT AND SATURDAY DUE TO
EXPECTED RISING TEMPERATURES FROM THE SW. BLENDED THE HRRR WINDS
INTO THE GRIDS TO INCREASE WINDS IN FAVORED AREAS FOR SE
DIRECTION. SCT
PREVIOUS DISCUSSION...
WARMER CONDITIONS ARE EXPECTED THIS TERM WITH ABOVE NORMAL
READINGS EXPECTED FOR THE FIRST TIME SINCE SUNDAY.
A STRONG PACIFIC SYSTEM HAS PUSHED ONSHORE IN THE PACIFIC NW WITH A
WARM FRONT NOW MOVING NE THROUGH SW MONTANA. THIS FRONT IS EXPECTED
TO CONTINUE NE ALLOWING TEMPS TO RISE TONIGHT. 850 MB TEMPS RISE
SIGNIFICANTLY AS THE REMAINING ARCTIC AIR-MASS GETS NUDGED TO OUR
NE...WITH READINGS OVER GLASGOW RISING FROM ABOUT -12*C THIS
AFTERNOON TO +3*C SATURDAY MORNING. LOW PRESSURE WILL BEGIN TO
DEVELOP OVER SOUTHERN ALBERTA SATURDAY AS THE UPPER TROUGH MOVES IN.
THE MODELS THEN TAKE THIS LOW EAST NEAR THE INTERNATIONAL
BORDER...FAR ENOUGH NORTH FOR THE MILD PACIFIC AIR-MASS TO FLOOD INTO
THE AREA SATURDAY. OF COURSE SNOW-COVER WILL TEMPER THIS WITH
FURTHER COOLING IN THE NORTHERN ZONES DUE TO LACK OF MIXING.
MOISTURE AHEAD OF THIS SYSTEM LOOKS MINIMAL SO SLIGHT CHANCE POPS
LOOK GOOD FOR NOW. MODELS SEEM TO PUT A FINGER THOUGH ON SOME
DEVELOPMENT SATURDAY AFTERNOON IN THE SOUTHEAST ZONES. THIS AREA
QUICKLY MOVES EAST TO CREATE A HEADACHE FOR AREAS THERE.
THE UPPER TROUGH LATE SATURDAY INTO SUNDAY WRAPS UP A
BIT...ESPECIALLY ON THE GFS. THIS MODEL HAS BEEN CONSISTENT AND
KNOCKS TEMPS BACK DOWN ACROSS THE AREA...AND MIXING NW WINDS TO
THE SURFACE AS WELL. SOME SNOW-SHOWER ACTIVITY CAN BE EXPECTED
TOO...SPREADING FROM NW TO SE DURING THE MORNING. SNOWFALL LOOKS
TO BE LESS THAN AN INCH. JAMBA
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
NOT TOO MANY CHANGES TO THE LONG TERM...WITH THE MAIN FOCUS BEING
THE RETURN OF THE POSSIBILITY OF ABOVE AVERAGE TEMPERATURES NEXT WEEK.
BRIEF RIDGING STILL LOOKS TO MOVE IN EARLY IN THE WORK
WEEK...FOLLOWED BY A SERIES OF SHORTWAVE TROUGHS.
DECIDED TO RAISE TEMPS A BIT FOR NEXT WEEK DUE TO THE MAJORITY OF
MODEL GUIDANCE HINTING TOWARDS WARMER TEMPERATURES COMPARED TO
PREVIOUS RUNS. THE CHALLENGE WILL STILL BE FIGURING OUT JUST HOW WARM
WE WILL GET...ESPECIALLY WITH A FEW BRIEF SHOTS OF COLD AIR WITH
THE PASSING SHORTWAVES AND CORRESPONDING COLD FRONTS. ALTHOUGH
WINDS STILL LOOK TO BE STRONG LATER IN THE PERIOD...THE AMOUNT OF
MIXING STILL MAY PREVENT US FROM BRINGING THE WARMER AIR DOWN TO
THE SURFACE. FORECASTED HIGHS ARE STILL A BIT BELOW MOST MODEL
SOLUTIONS.
WEDNESDAY STILL LOOKS TO BE THE WARMEST DAY NEXT WEEK...WITH THE
GFS BRINGING 850 TEMPS AROUND 4C TO 8C OVER THE CWA. HOWEVER...THE
12Z ECMWF SUGGESTS THAT WEDNESDAY AND THURSDAY LOOK TO BE
WARM...WITH THURSDAY BEING THE WARMER OF THE TWO DAYS. 850 TEMPS
ARE JUST A BIT HIGHER ON THURSDAY ACCORDING TO THE ECMWF BY ABOUT
2C TO 4C COMPARED TO WEDNESDAY. EITHER WAY...NEXT WEEK STILL LOOKS
TO BE A WELCOMED RETURN TO WARMER TEMPERATURES. BARNWELL
PREVIOUS LONG TERM DISCUSSION...PATTERN RETURNS TO WHAT HAS BEEN
COMMON THIS WINTER...ZONAL FLOW OFF THE PACIFIC WITH A SERIES OF
WEAK RIDGES AND TROF...AND ARCTIC AIRMASS STAYING WELL TO THE
NORTH. MODEL TIMING OF THE FEATURES NOT TOO FAR OFF FROM EACH
OTHER...ALTHOUGH THIS DOES SLIP TOWARD THE END OF THE FORECAST
PERIOD.
UPPER TROF EXITING THE REGION SUNDAY NIGHT WITH RIDGE SLIDING
ACROSS THE STATE ON MONDAY WITH ANOTHER TROF PUSHING THROUGH THE
PACIFIC NORTHWEST. COLD FRONT IS PUSHED INTO THE STATE MONDAY
NIGHT AS UPPER TROF TRACKS ALONG THE CANADIAN BORDER.
JET PUNCHES INTO WESTERN CANADA BEHIND THE TROF ON TUESDAY
NIGHT..DEVELOPING INTO A STRONG CHINOOK ACROSS MONTANA ON
WEDNESDAY. AS JET DIVES INTO THE NORTHERN PLAINS...COLD FRONT
DROPS THROUGH MONTANA...AND ENOUGH DYNAMICS AND MOISTURE FOR A
LITTLE PRECIPITATION ON WEDNESDAY. PATTERN REPEATS FOR THURSDAY
INTO THURSDAY NIGHT...ALTHOUGH AIRMASS SLIGHTLY COLDER BEHIND THIS
SECOND COLD FRONT.
POTENTIAL FOR WINDY CONDITIONS WILL BE INCREASING ALTHOUGH MIXING
WILL CONTINUE TO BE A PROBLEM...ESPECIALLY WITH INCREASED SNOW
COVER IN CONTRAST TO EARLIER IN THE MONTH. EBERT
&&
.AVIATION...
THERE WILL BE A SCATTERED TO BROKEN LAYER AROUND 2K FT AGL OVER
PARTS OF THE FORECAST AREA TONIGHT...OTHERWISE MAINLY VFR WITH
BROKEN TO OVERCAST LAYERS ABOVE 8K FT AGL. E WINDS 10 TO 15 KT AT
GGW. SLIGHT CHANCE OF A LITTLE LIGHT FREEZING RAIN LATE TONIGHT AND
SATURDAY MORNING. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1109 PM CST FRI JAN 20 2012
.AVIATION...06Z TAF. DRY CONDITIONS EXPECTED FOR THIS TAF
PERIOD...WITH MAIN CONCERNS LYING WITH CLOUD COVER EARLY ON...THEN
A SWITCH IN WINDS. CURRENTLY SEEING A SMALL AREA OF LOW LEVEL
STRATUS LINGERING OVER THE TERMINAL AREA...RESULTING IN MVFR CIGS.
COULD SEE THIS CONTINUE FOR A FEW MORE HOURS...BUT IS EXPECTED TO
DIMINISH WITH VFR CONDITIONS RETURNING. THROUGH THE REST OF THE
TAF PERIOD ANY CLOUD COVER IS EXPECTED TO REMAIN CONFINED TO THE
MID/UPPER LEVELS. AS FAR AS WINDS GO...SPEEDS CONTINUE TO DIMINISH
AS SURFACE HIGH PRESSURE DRIFTS EAST THROUGH THE AREA. LATER THIS
MORNING WINDS WILL GRADUALLY SWITCH TO THE SOUTH ON THE BACKSIDE
OF THE SFC HIGH...AND WILL REMAIN SOUTHERLY THROUGH THE REMAINDER
OF THE TAF PERIOD. A TIGHTENING PRESSURE GRADIENT DEVELOPING
ACROSS THE AREA WILL BRING INCREASING SPEEDS THROUGH THE DAYTIME
HOURS...WITH SPEEDS THIS AFTERNOON REACHING NEAR 20 TO 25 MPH WITH
HIGHER GUSTS.
&&
.PREV DISCUSSION... /ISSUED 1023 PM CST FRI JAN 20 2012/
UPDATE...SOME STRATUS IS MAKING ITS WAY FROM THE NORTH BUT SHOULD
EVENTUALLY HAVE A HARD TIME HOLDING TOGETHER DURING THE
OVERNIGHT...BUT HAVE INCREASED SKY COVER FOR THE NEXT SEVERAL
HOURS. ALSO RAISED TEMPERATURES A BIT...ESPECIALLY IN THE
SOUTHWESTERN CWA FOR LOWS TONIGHT.
PREV DISCUSSION... /ISSUED 318 PM CST FRI JAN 20 2012/
SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
UPDATE...HEINLEIN
SHORT...BRYANT
LONG...KING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1023 PM CST FRI JAN 20 2012
.UPDATE...SOME STRATUS IS MAKING ITS WAY FROM THE NORTH BUT SHOULD
EVENTUALLY HAVE A HARD TIME HOLDING TOGETHER DURING THE
OVERNIGHT...BUT HAVE INCREASED SKY COVER FOR THE NEXT SEVERAL
HOURS. ALSO RAISED TEMPERATURES A BIT...ESPECIALLY IN THE
SOUTHWESTERN CWA FOR LOWS TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 510 PM CST FRI JAN 20 2012/
AVIATION...00Z KGRI TAF. CEILINGS ARE GOING TO BE A TOUGH CALL
THIS EVENING. SOME STRATUS ARE HEADING TOWARD THE TERMINAL FROM
THE NORTH...BUT ISENTROPIC DOWNGLIDE WILL BE COMPETING AGAINST
THE STRATUS HOLDING TOGETHER FOR LONG. LOOKING AT THE LATEST
SATELLITE DATA AND SPEED TOOLS...IT APPEARS THAT THE STRATUS
SHOULD ARRIVE A BIT OVER AN HOUR AFTER THIS FORECAST IF
VALID...BUT WITH ISENTROPIC DOWNGLIDE...WILL LIKELY ONLY HOLD
TOGETHER THROUGH THE EVENING AND THEN SCATTER BY THE EARLY
OVERNIGHT. WIND WILL SWITCH FROM THE NORTH TO THE SOUTH OVERNIGHT
AS A SURFACE HIGH SLIDES EAST. SOUTH WIND CAN GET A BIT GUSTY BY
SATURDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT INCREASES.
PREV DISCUSSION... /ISSUED 318 PM CST FRI JAN 20 2012/
SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/UPDATE...HEINLEIN
SHORT TERM...BRYANT
LONG TERM...KING
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EST SAT JAN 21 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING
UNSETTLED WEATHER TO THE CAROLINAS AND SOUTHERN VIRGINIA THROUGH
TONIGHT. AN AREA OF HIGH PRESSURE WILL BUILD SOUTH INTO OUR
REGION SUNDAY...BRINGING DAMP AND CHILLY CONDITIONS. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 925 PM FRIDAY...
THROUGH SATURDAY NIGHT: LIGHT RAIN AND A WEDGE LIKE AIR MASS HAVE
DEVELOPED FROM CENTRAL NORTH CAROLINA TO NORTHERN GA THIS
EVENING...WHILE A WARM FRONT IS STARTING TO LIFT THROUGH AL AS A
WEAK LOW PRESSURE DEVELOPS OVER ARKANSAS. THE LIGHT RAIN...SUPPORTED
BY ISENTROPIC LIFT ALONG AND NORTH OF THE WEDGE FRONT/WEAK 850
MILLIBAR WARM FRONT AND DIFFLUENT FLOW IN THE EXIT OF A WEAK 300MB
JET AXIS STRETCHED ACROSS THE LOWER MISSISSIPPI VALLEY...CONTINUES
TO BLOSSOM TO OUR SOUTHWEST AND SPREAD ACROSS CENTRAL NORTH
CAROLINA. THE ONGOING RAINFALL IS LIGHT AND RAINFALL TOTALS HAVE
BEEN BELOW A TENTH OF AN INCH. RUC ISENTROPIC LIFT FORECASTS SHOW
STRONG LIFT CONTINUING IN THE 290 TO 300 KELVIN LAYER THROUGH 09Z
BEFORE SOME DRIER AIR ALOFT..NOTED AT 700MB...ADVECTS IN FROM THE
SOUTHWEST AHEAD OF THE TROUGH AXIS TO APPROACH LATER IN THE DAY
SATURDAY. THUS..RAIN IS LIKELY TO TURN TO DRIZZLE FROM WEST TO EAST
AFTER 09Z..BUT CATEGORICAL POPS SEEM NECESSARY EVERYWHERE FOR THE
BALANCE OF THE NIGHT.
WITH A 5000 FOOT WEDGE AIR MASS (PER 00Z KGSO RAOB) LOCKING
IN...THE CURRENT FORECAST OF TEMPERATURES IN THE LOW TO MID 40S
WILL REMAINING NEARLY STEADY OR RISING SLIGHTLY LOOKS GOOD. -SMITH
THE WARM ADVECTION DRIVEN PRECIPITATION SHOULD COME TO AN END FROM
WEST TO EAST BY EARLY SATURDAY MORNING. HOWEVER...THE LULL IN
PRECIPITATION WILL BE SHORT LIVED AS A COLD FRONT ADVANCES TOWARDS
THE AREA DURING THE DAY ON SATURDAY. SOUTHWESTERLY FLOW AHEAD OF
THE FRONT WILL PUMP WARM AND MOIST AIR INTO THE REGION...WITH MAX
TEMPERATURES EXPECTED TO RISE INTO THE 60S AREAWIDE (MAYBE EVEN
PUSHING 70 DEGREES ACROSS THE SOUTHEAST). ALTHOUGH SOME DIURNAL
DESTABILIZATION IS EXPECTED TO OCCUR ACROSS THE EASTERN HALF OF
THE FORECAST AREA...DEWPOINTS ARE ONLY EXPECTED TO REACH INTO THE
LOW TO MID 50S...THUS LIMITING THE AMOUNT OF INSTABILITY. NAM
FORECAST SOUNDINGS SHOW AT BEST CAPE VALUES OF LESS THAN 500
J/KG...WHILE THE GFS FORECAST SOUNDINGS SHOW NO INSTABILITY AT
ALL. NEVERTHELESS...DECENT SHEAR WILL BE IN PLACE OVER THE REGION
AND IF WE ARE ABLE TO REALIZE SOME OF THE INSTABILITY THE NAM
INDICATES...AN ISOLATED THUNDERSTORM OR TWO CANNOT BE RULED OUT
SATURDAY AFTERNOON. HOWEVER...FOR NOW WILL LEAVE ANY MENTION OF
THUNDER OUT OF THE FORECAST DUE TO THE UNCERTAINTY.
OVERALL...AFTER THE BRIEF LULL IN PRECIPITATION SATURDAY
MORNING...AM EXPECTING A LINE OF SHOWERS TO PROGRESS FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON/EVENING.
SUN AND SUN NIGHT: A STRENGTHENING 1030 MILLIBAR PLUS SURFACE COLD
AIR HIGH OVER NEW ENGLAND WILL ADVECT COLDER AND DRIER AIR INTO
CENTRAL NORTH CAROLINA DURING THE PREDAWN HOURS...AND THIS WILL SET
THE STAGE FOR A SHORT LIVED HYBRID DAMMING EVENT ON SUNDAY AS
CONTINUED SOUTHWEST FLOW ALOFT WILL SUPPORT WEAK OVERRUNNING ACROSS
CENTRAL NORTH CAROLINA AS THE NEXT PACIFIC TROUGH PUSHES EAST INTO
THE CENTRAL UNITED STATES. WITH MOIST COLUMN NOT EXTENDING MUCH
BEYOND 700 MILLIBAR...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE
EXPECTED WITH PERIODS OF DRIZZLE THROUGHOUT THE DAY...WITH THE
POTENTIAL THAT THE NORTHWEST PIEDMONT COULD SEE A BRIEF PERIOD OF
FREEZING DRIZZLE EARLY SUNDAY MORNING AS MODEL SOUNDINGS DRIVE
SURFACE TEMPERATURES SUNDAY MORNING INTO THE LOWER TO MID 30S WITH
WET BULB FREEZING LINE DEPICTED IN THE SAME CLIMATOLOGICALLY FAVORED
AREA AS WELL. FURTHERMORE A HANDFUL OF SREF MEMBERS ALSO INDICATE A
BRIEF CHANGEOVER OF FREEZING DRIZZLE WITH LITTLE TO NO ACCUMULATION(
A COUPLE OF HUNDREDTHS OR LESS). SURFACE WET BULBS ARE EXPECTED TO
REBOUND INTO THE MID 30S THROUGH THE MORNING WITH MINIMAL RECOVERY
THROUGHOUT THE DAY. AFTER MORNING LOWS IN THE MID TO UPPER 30S NORTH
TO MID 40S SOUTH...EXPECT A NET INCREASE OF ONLY 3 TO 5 DEGREES
ACROSS THE AREA.
STALLED FRONTAL ZONE SOUTH OF THE AREA BEGINS TO RETREAT NORTHWARD
AS A WARM FRONT SUNDAY NIGHT...WITH THE SOUTHERN RETURN FLOW
OVERTAKING THE SHALLOW COLD AIR DAMMING AIR MASS ALONG THE
SOUTHERN AND EASTERN FLANKS...WHILE REMAINING LOCKED IN OVER THE
NORTHWEST PIEDMONT REGION. THIS WILL FAVOR NEAR STEADY
TEMPERATURES OVERNIGHT ACROSS THE NORTHWEST WITH TEMPERATURES
SLIGHTLY RISING ACROSS THE SANDHILLS AND COASTAL COUNTIES.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 250 AM SATURDAY...
MON AND MON NIGHT: A TRANSITION FROM A FORMIDABLE CAD REGIME -- BY
THIS TIME AN IN-SITU ONE OWING TO THE QUICK DEPARTURE OF THE
PROGRESSIVE PARENT HIGH -- TO BRIEF WARM SECTOR OVER AT LEAST
SIZABLE PORTION OF CENTRAL NC...TO A COLD FRONTAL PASSAGE...WILL ALL
OCCUR IN LESS THAN 24 HOURS THIS PERIOD. THE WEDGE IS EXPECTED TO
QUICKLY ERODE ALONG THE EDGES WHERE THE CHARACTERISTIC STABILITY AND
DEPTH ARE LOWER THROUGH MIDDAY...BUT HOLD STUBBORNLY IN THE HEART OF
THE WEDGE OVER THE NW PIEDMONT INTO THE EARLY AFTERNOON HOURS...BEST
REPRESENTED BY THE 00Z ECMWF AND NAM/WRF (DESPITE THE NAM/WRF
DISCOUNTED SOLUTION OF A MUCH FARTHER NORTHWARD-DISPLACED SURFACE
LOW IN SOUTHERN CANADA...AS OPPOSED TO THE CONSENSUS OF OTHER
GUIDANCE WHICH HAS THE LOW IN THE UPPER MIDWEST). AS
SUCH...TEMPERATURES SHOULD WARM INTO THE UPPER 60S-LOWER 70S IN WAA
AND A FEW BINOVC OVER EASTERN NC...INCLUDING THE RAH COASTAL
PLAIN...WHILE THE NW PIEDMONT IS APT TO STRUGGLE THROUGH THE 40S FOR
MUCH OF THE DAY...AND TOP OUT ONLY IN THE MID-UPPER 50S FOR A COUPLE
OF HOURS VERY LATE IN THE AFTERNOON. NWP GUIDANCE INDICATES ONLY A
BRIEF PERIOD OF DEEP MOISTENING AND MID LEVEL CAP EROSION
IMMEDIATELY AHEAD OF THE FRONT...AND EVEN THEN LAPSE RATES ARE
PROJECTED TO REMAIN PSEUDO-MOIST ADIABATIC OWING TO THE PASSAGE OF
THE PARENT NEGATIVELY-TILTED S/W TROUGH AND ACCOMPANYING CAA ALOFT
TO THE NW OF THE WARM SECTOR OVER CENTRAL AND EASTERN NC. AS
SUCH...THUNDER POTENTIAL IS QUITE LOW...AND THE PROBABILITY OF
SHOWERS WILL BE HELD IN THE 30-60 PERCENT RANGE...HIGHEST NORTH AND
NORTHWEST IN CLOSER PROXIMITY TO BOTH THE S/W TROUGH ALOFT AND THE
RETREATING/ERODING WEDGE FRONT. TIMING DIFFERENCES REMAIN WRT THE
FRONTAL PASSAGE AND FOLLOWING CAA MON NIGHT...SO ONLY MINOR
MODIFICATION TO LOWS IN THE UPPER 30S TO MID-UPPER 40S WAS
JUSTIFIED.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...
TUE THROUGH FRI: MILD POST-FRONTAL HIGH PRESSURE WILL FOLLOW FOR THE
MIDDLE OF THE WEEK...WITH TEMPERATURES RANGING FROM THE UPPER 50S TO
MIDDLE 60S FOR HIGHS...WARMEST THU. NWP GUIDANCE CONTINUES TO
INDICATE THE FRONTAL ZONE FORECAST TO CROSS OUR REGION MON NIGHT
WILL STALL OVER THE GULF COAST...BUT SOLUTIONS VARY WILDLY WRT TO
HOW QUICKLY AND PHASED WITH THE NORTHERN STREAM (IF AT ALL) A
SOUTHERN STREAM UPPER LOW WILL PROGRESS EASTWARD AND ACTIVATE THE
STALLED FRONTAL ZONE WITH OUR ENSUING NEXT CHANCE OF RAIN. WILL
ACCORDINGLY MAINTAIN FORECAST CONTINUITY FROM PREVIOUS
SHIFTS...WHICH DEPICTS SLIGHT TO LOW CHANCE PROBABILITIES WED NIGHT
ONWARD AND ACCOUNTS FOR THE INHERENT FORECAST UNCERTAINTY.
HOWEVER...REALISTICALLY THERE WILL BE ONLY A COUPLE OF RELATIVELY
BRIEF BOUTS...ON THE ORDER OF SIX HOURS AT A TIME...OF RAINFALL
DURING THE ENTIRE PERIOD - ONE WITH THE NORTHWARD RETREAT OF THE
FRONTAL ZONE AHEAD OF THE INEVITABLE SURFACE LOW ATTENDING THE
SOUTHERN STREAM...AND ANOTHER WITH THE TRAILING COLD FRONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 120 AM...
MOSTLY LIFR CEILINGS NORTHWEST PIEDMONT WITH IFR TO MVFR
ELSEWHERE. MOSTLY MVFR VISIBILITIES IN AREAS OF RAIN. SOME
IMPROVEMENT IN CEILINGS AFTER SUNRISE... ESPECIALLY LATE AFTERNOON
INTO EARLY EVENING AS CHARACTER OF PRECIPITATION CHANGES FROM
RAIN TO SHOWERS. CONDITIONS DETERIORATE IN THE EARLY EVENING TO
IFR TO MVFR CEILINGS WITH MVFR VISIBILITIES IN PRECIPITATION.
SUB VFR CONDITIONS DOMINATE INTO MONDAY MORNING. THEN VFR INTO
WEDNESDAY EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NEAR TERM...SMITH/KRR
SHORT TERM...MWS
LONG TERM...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
121 AM EST SAT JAN 21 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING
UNSETTLED WEATHER TO THE CAROLINAS AND SOUTHERN VIRGINIA THROUGH
TONIGHT. AN AREA OF HIGH PRESSURE WILL BUILD SOUTH INTO OUR
REGION SUNDAY...BRINGING DAMP AND CHILLY CONDITIONS. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 925 PM FRIDAY...
THROUGH SATURDAY NIGHT: LIGHT RAIN AND A WEDGE LIKE AIR MASS HAVE
DEVELOPED FROM CENTRAL NORTH CAROLINA TO NORTHERN GA THIS
EVENING...WHILE A WARM FRONT IS STARTING TO LIFT THROUGH AL AS A
WEAK LOW PRESSURE DEVELOPS OVER ARKANSAS. THE LIGHT RAIN...SUPPORTED
BY ISENTROPIC LIFT ALONG AND NORTH OF THE WEDGE FRONT/WEAK 850
MILLIBAR WARM FRONT AND DIFFLUENT FLOW IN THE EXIT OF A WEAK 300MB
JET AXIS STRETCHED ACROSS THE LOWER MISSISSIPPI VALLEY...CONTINUES
TO BLOSSOM TO OUR SOUTHWEST AND SPREAD ACROSS CENTRAL NORTH
CAROLINA. THE ONGOING RAINFALL IS LIGHT AND RAINFALL TOTALS HAVE
BEEN BELOW A TENTH OF AN INCH. RUC ISENTROPIC LIFT FORECASTS SHOW
STRONG LIFT CONTINUING IN THE 290 TO 300 KELVIN LAYER THROUGH 09Z
BEFORE SOME DRIER AIR ALOFT..NOTED AT 700MB...ADVECTS IN FROM THE
SOUTHWEST AHEAD OF THE TROUGH AXIS TO APPROACH LATER IN THE DAY
SATURDAY. THUS..RAIN IS LIKELY TO TURN TO DRIZZLE FROM WEST TO EAST
AFTER 09Z..BUT CATEGORICAL POPS SEEM NECESSARY EVERYWHERE FOR THE
BALANCE OF THE NIGHT.
WITH A 5000 FOOT WEDGE AIR MASS (PER 00Z KGSO RAOB) LOCKING
IN...THE CURRENT FORECAST OF TEMPERATURES IN THE LOW TO MID 40S
WILL REMAINING NEARLY STEADY OR RISING SLIGHTLY LOOKS GOOD. -SMITH
THE WARM ADVECTION DRIVEN PRECIPITATION SHOULD COME TO AN END FROM
WEST TO EAST BY EARLY SATURDAY MORNING. HOWEVER...THE LULL IN
PRECIPITATION WILL BE SHORT LIVED AS A COLD FRONT ADVANCES TOWARDS
THE AREA DURING THE DAY ON SATURDAY. SOUTHWESTERLY FLOW AHEAD OF
THE FRONT WILL PUMP WARM AND MOIST AIR INTO THE REGION...WITH MAX
TEMPERATURES EXPECTED TO RISE INTO THE 60S AREAWIDE (MAYBE EVEN
PUSHING 70 DEGREES ACROSS THE SOUTHEAST). ALTHOUGH SOME DIURNAL
DESTABILIZATION IS EXPECTED TO OCCUR ACROSS THE EASTERN HALF OF
THE FORECAST AREA...DEWPOINTS ARE ONLY EXPECTED TO REACH INTO THE
LOW TO MID 50S...THUS LIMITING THE AMOUNT OF INSTABILITY. NAM
FORECAST SOUNDINGS SHOW AT BEST CAPE VALUES OF LESS THAN 500
J/KG...WHILE THE GFS FORECAST SOUNDINGS SHOW NO INSTABILITY AT
ALL. NEVERTHELESS...DECENT SHEAR WILL BE IN PLACE OVER THE REGION
AND IF WE ARE ABLE TO REALIZE SOME OF THE INSTABILITY THE NAM
INDICATES...AN ISOLATED THUNDERSTORM OR TWO CANNOT BE RULED OUT
SATURDAY AFTERNOON. HOWEVER...FOR NOW WILL LEAVE ANY MENTION OF
THUNDER OUT OF THE FORECAST DUE TO THE UNCERTAINTY.
OVERALL...AFTER THE BRIEF LULL IN PRECIPITATION SATURDAY
MORNING...AM EXPECTING A LINE OF SHOWERS TO PROGRESS FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON/EVENING.
SUN AND SUN NIGHT: A STRENGTHENING 1030 MILLIBAR PLUS SURFACE COLD
AIR HIGH OVER NEW ENGLAND WILL ADVECT COLDER AND DRIER AIR INTO
CENTRAL NORTH CAROLINA DURING THE PREDAWN HOURS...AND THIS WILL SET
THE STAGE FOR A SHORT LIVED HYBRID DAMMING EVENT ON SUNDAY AS
CONTINUED SOUTHWEST FLOW ALOFT WILL SUPPORT WEAK OVERRUNNING ACROSS
CENTRAL NORTH CAROLINA AS THE NEXT PACIFIC TROUGH PUSHES EAST INTO
THE CENTRAL UNITED STATES. WITH MOIST COLUMN NOT EXTENDING MUCH
BEYOND 700 MILLIBAR...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE
EXPECTED WITH PERIODS OF DRIZZLE THROUGHOUT THE DAY...WITH THE
POTENTIAL THAT THE NORTHWEST PIEDMONT COULD SEE A BRIEF PERIOD OF
FREEZING DRIZZLE EARLY SUNDAY MORNING AS MODEL SOUNDINGS DRIVE
SURFACE TEMPERATURES SUNDAY MORNING INTO THE LOWER TO MID 30S WITH
WET BULB FREEZING LINE DEPICTED IN THE SAME CLIMATOLOGICALLY FAVORED
AREA AS WELL. FURTHERMORE A HANDFUL OF SREF MEMBERS ALSO INDICATE A
BRIEF CHANGEOVER OF FREEZING DRIZZLE WITH LITTLE TO NO ACCUMULATION(
A COUPLE OF HUNDREDTHS OR LESS). SURFACE WET BULBS ARE EXPECTED TO
REBOUND INTO THE MID 30S THROUGH THE MORNING WITH MINIMAL RECOVERY
THROUGHOUT THE DAY. AFTER MORNING LOWS IN THE MID TO UPPER 30S NORTH
TO MID 40S SOUTH...EXPECT A NET INCREASE OF ONLY 3 TO 5 DEGREES
ACROSS THE AREA.
STALLED FRONTAL ZONE SOUTH OF THE AREA BEGINS TO RETREAT NORTHWARD
AS A WARM FRONT SUNDAY NIGHT...WITH THE SOUTHERN RETURN FLOW
OVERTAKING THE SHALLOW COLD AIR DAMMING AIR MASS ALONG THE
SOUTHERN AND EASTERN FLANKS...WHILE REMAINING LOCKED IN OVER THE
NORTHWEST PIEDMONT REGION. THIS WILL FAVOR NEAR STEADY
TEMPERATURES OVERNIGHT ACROSS THE NORTHWEST WITH TEMPERATURES
SLIGHTLY RISING ACROSS THE SANDHILLS AND COASTAL COUNTIES.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 250 AM SATURDAY...
MON AND MON NIGHT: A TRANSITION FROM A FORMIDABLE CAD REGIME -- BY
THIS TIME AN IN-SITU ONE OWING TO THE QUICK DEPARTURE OF THE
PROGRESSIVE PARENT HIGH -- TO BRIEF WARM SECTOR OVER AT LEAST
SIZABLE PORTION OF CENTRAL NC...TO A COLD FRONTAL PASSAGE...WILL ALL
OCCUR IN LESS THAN 24 HOURS THIS PERIOD. THE WEDGE IS EXPECTED TO
QUICKLY ERODE ALONG THE EDGES WHERE THE CHARACTERISTIC STABILITY AND
DEPTH ARE LOWER THROUGH MIDDAY...BUT HOLD STUBBORNLY IN THE HEART OF
THE WEDGE OVER THE NW PIEDMONT INTO THE EARLY AFTERNOON HOURS...BEST
REPRESENTED BY THE 00Z ECMWF AND NAM/WRF (DESPITE THE NAM/WRF
DISCOUNTED SOLUTION OF A MUCH FARTHER NORTHWARD-DISPLACED SURFACE
LOW IN SOUTHERN CANADA...AS OPPOSED TO THE CONSENSUS OF OTHER
GUIDANCE WHICH HAS THE LOW IN THE UPPER MIDWEST). AS
SUCH...TEMPERATURES SHOULD WARM INTO THE UPPER 60S-LOWER 70S IN WAA
AND A FEW BINOVC OVER EASTERN NC...INCLUDING THE RAH COASTAL
PLAIN...WHILE THE NW PIEDMONT IS APT TO STRUGGLE THROUGH THE 40S FOR
MUCH OF THE DAY...AND TOP OUT ONLY IN THE MID-UPPER 50S FOR A COUPLE
OF HOURS VERY LATE IN THE AFTERNOON. NWP GUIDANCE INDICATES ONLY A
BRIEF PERIOD OF DEEP MOISTENING AND MID LEVEL CAP EROSION
IMMEDIATELY AHEAD OF THE FRONT...AND EVEN THEN LAPSE RATES ARE
PROJECTED TO REMAIN PSEUDO-MOIST ADIABATIC OWING TO THE PASSAGE OF
THE PARENT NEGATIVELY-TILTED S/W TROUGH AND ACCOMPANYING CAA ALOFT
TO THE NW OF THE WARM SECTOR OVER CENTRAL AND EASTERN NC. AS
SUCH...THUNDER POTENTIAL IS QUITE LOW...AND THE PROBABILITY OF
SHOWERS WILL BE HELD IN THE 30-60 PERCENT RANGE...HIGHEST NORTH AND
NORTHWEST IN CLOSER PROXIMITY TO BOTH THE S/W TROUGH ALOFT AND THE
RETREATING/ERODING WEDGE FRONT. TIMING DIFFERENCES REMAIN WRT THE
FRONTAL PASSAGE AND FOLLOWING CAA MON NIGHT...SO ONLY MINOR
MODIFICATION TO LOWS IN THE UPPER 30S TO MID-UPPER 40S WAS
JUSTIFIED.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...
TUE THROUGH FRI: MILD POST-FRONTAL HIGH PRESSURE WILL FOLLOW FOR THE
MIDDLE OF THE WEEK...WITH TEMPERATURES RANGING FROM THE UPPER 50S TO
MIDDLE 60S FOR HIGHS...WARMEST THU. WHILE NWP GUIDANCE CONTINUES TO
INDICATE THE FRONTAL ZONE FORECAST TO CROSS OUR REGION MON NIGHT
WILL STALL OVER THE GULF COAST...BUT SOLUTIONS VARY WILDLY WRT TO
HOW QUICKLY AND PHASED WITH THE NORTHERN STREAM (IF AT ALL) A
SOUTHERN STREAM UPPER LOW WILL PROGRESS EASTWARD AND ACTIVATE THE
STALLED FRONTAL ZONE WITH OUR ENSUING NEXT CHANCE OF RAIN. WILL
ACCORDINGLY MAINTAIN FORECAST CONTINUITY FROM PREVIOUS
SHIFTS...WHICH DEPICTS SLIGHT TO LOW CHANCE PROBABILITIES WED NIGHT
ONWARD AND ACCOUNTS FOR THE INHERENT FORECAST UNCERTAINTY.
HOWEVER... REALISTICALLY THERE WILL BE ONLY A COUPLE OF RELATIVELY
BRIEF BOUTS...ON THE ORDER OF SIX HOURS AT A TIME...OF RAINFALL
DURING THE ENTIRE PERIOD - ONE WITH THE NORTHWARD RETREAT OF THE
FRONTAL ZONE AHEAD OF THE INEVITABLE SURFACE LOW ATTENDING THE
SOUTHERN STREAM...AND ANOTHER WITH THE TRAILING COLD FRONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 120 AM...
MOSTLY LIFR CEILINGS NORTHWEST PIEDMONT WITH IFR TO MVFR
ELSEWHERE. MOSTLY MVFR VISIBILITIES IN AREAS OF RAIN. SOME
IMPROVEMENT IN CEILINGS AFTER SUNRISE... ESPECIALLY LATE AFTERNOON
INTO EARLY EVENING AS CHARACTER OF PRECIPITATION CHANGES FROM
RAIN TO SHOWERS. CONDITIONS DETERIORATE IN THE EARLY EVENING TO
IFR TO MVFR CEILINGS WITH MVFR VISIBILITIES IN PRECIPITATION.
SUB VFR CONDITIONS DOMINATE INTO MONDAY MORNING. THEN VFR INTO
WEDNESDAY EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NEAR TERM...SMITH/KRR
SHORT TERM...MWS
LONG TERM...MWS
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
310 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 300 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
LAST OF MAINLY OVER FAR SOUTHEAST SOUTH DAKOTA SHOULD EXIT OVER
FIRST FEW HOURS OF TAF PERIOD. VISIBILITIES ARE MORE TRICKY...WITH
POTENTIAL FOR SPOTTY MVFR CONDITIONS THROUGH THE PERIOD. FIRST WILL
BE LATE TONIGHT...AS LIGHT WINDS/CLEAR SKIES/FRESH SNOW COVER ALLOW
FOR STRONG RADIATIVE COOLING. COULD SEE AREAS OF ICE CRYSTALS
DEVELOP IN THE SURFACE RIDGE AXIS...AND HAVE ADDED A FEW HOURS OF
MVFR VISIBILITY TO ALL TAFS DURING PERIOD OF CALM WINDS OVERNIGHT.
SECOND...INCREASING SOUTHERLY WINDS AFTER 15Z-16Z SATURDAY WITH
FREQUENT GUSTS OF 25-30KTS LIKELY...WHICH MAY PRODUCE BLOWING AND
DRIFTING OF THE RELATIVELY FLUFFY FRESH SNOWCOVER. BLOWING SNOW
COULD RESULT IN AREAS OF MVFR OR EVEN SPOTTY IFR VISIBILITY IN OPEN
AREAS DURING THE LATE MORNING/AFTERNOON SATURDAY...AND HAVE MENTION
OF MVFR VISIBILITY IN ALL TAFS DURING PERIOD OF EXPECTED STRONGEST
WIND GUSTS...WHICH COULD APPROACH 35KTS 19Z-23Z. /JH
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
317 AM CST SAT JAN 21 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEAR LAKE MICHIGAN THE MAIN ISSUE WILL BE HANDLING LAKE EFFECT
TRENDS. NORTHEAST WINDS IN SHALLOW LAYER FROM 975 MB TO 900 MB.
LAPSE RATES ARE NOT TO STEEP WITH AROUND 3 C/KM AT MILWAUKEE BUT
NEAR 6C/KM NEAR KENOSHA AT 09Z BUT LAPSE RATES INCREASE TO NEAR
9C/KM AT 18Z WITH INVERSION HEIGHT AROUND 3 THSD FT. LOW LEVEL FLOW
WEAKENS AND BECOMES MORE EAST. THEREFORE EXPECT THE SNOW BAND NEAR
KENOSHA TO CONTINUE TO WEAKEN AND THEN EVENTUALLY BECOME MORE
DIFFUSE WITH GENERAL LIGHT SNOW/FLURRIES NEAR THE LAKE. HRRR SHOWS
THE LAKE BAND PUSHING SOUTH THEN WEAKENING BUT INCREASING IN
COVERAGE. NAM SHOWS SOMETHING SIMILAR.
ELSEWHERE MOISTURE TRAPPED BLOW DEVELOPING INVERSION AROUND
3 THSD FT SHOULD SLOW ANY CLEARING FROM THE WEST. FORECAST
SOUNDINGS SHOW SOME CLEARING POTENTIAL OVER THE FRINGES OF THE
STRATUS SHIELD BUT THEN WITH THE EAST FLOW...LOW LEVELS MOISTEN SO
STRATUS/STRATOCUMULUS COULD EXPAND AGAIN.
MID LEVEL SHORTWAVE OVER THE EASTERN GREAT LAKES EXITS TO THE EAST
WITH MID LEVEL DRYING.
STRONG SHORTWAVE OVER THE PACIFIC NORTHWEST WILL REACH THE ROCKIES
TONIGHT. LOW/MID LEVEL WARM AIR ADVECTION BEGINS BUT THE 850 TO 700
MB LAYER IS FAIRLY DRY SO NOT EXPECTING ANY PRECIPITATION. BY
MIDNIGHT SOUNDINGS SHOW TEMPERATURES AROUND 800 MB ALREADY WARMING
ABOVE 0 CELSIUS OVER MUCH OF THE FORECAST AREA...AND ABOVE 0 C BY
SUNRISE. NAM SHOWS SATURATION BELOW 925 MB BUT DOES NOT APPEAR DEEP
ENOUGH MOIST LAYER FOR FREEZING DRIZZLE.
.SUNDAY AND MONDAY...FORECAST CONFIDENCE...MEDIUM
MODELS SLOWLY COMING INTO BETTER AGREEMENT FOR THE SUNDAY/MONDAY LOW
PRESSURE SYSTEM. THE GFS HAS TRENDED TOWARD THE SLOWER ECMWF AND
CANADIAN SOLUTIONS...WHILE THE NAM REMAINS THE QUICKEST. LEANED
FORECAST PRETTY HEAVILY TOWARD CONSISTENT ECMWF.
OVERALL...LOOKS LIKE A CHANCE FOR WARM ADVECTION PRECIP ON SUNDAY.
MID LEVELS ARE QUITE DRY IN SOUNDINGS...WITH VERY LITTLE ICE
EXPECTED. WITH SFC TEMPS BELOW FREEZING TO START THE DAY...KEPT
MENTION OF FREEZING RAIN. MENTIONED RAIN A CHANCE FOR RAIN AS WELL
IN THE AFTERNOON AS TEMPS WARM ABOVE FREEZING. ONLY REASON SNOW WAS
LEFT IN FOR SUNDAY IS THAT SOME MODELS DO SHOW SOME ICE CRYSTAL
POTENTIAL ABOVE THE DRY LAYER. DRY LAYER LOOKS LIKE IT WILL
GENERALLY DRY UP ANY ICE...BUT POTENTIAL FOR SEEDING IS THERE IF DRY
LAYER IS OVERDONE IN MODELS.
PRECIP AMOUNTS EXPECTED TO BE LIGHT DURING THE DAY SUNDAY...SO ANY
ICING WOULD BE FAIRLY LIMITED.
SFC LOW EXPECTED TO MOVE THROUGH SUNDAY NIGHT...ALONG WITH BEST SHOT
FOR PRECIP FROM THIS STORM. ENOUGH OVERLAP BETWEEN MODELS TO BUMP
POPS UP TO CATEGORICAL. LOOKS LIKE MAINLY RAIN EAST...MIXING WITH
SNOW WEST. MAY SEE EVENTUAL CHANGE OVER TO SNOW WEST TO EAST
BEGINNING LATE SUNDAY NIGHT OR MONDAY MORNING...WITH SOME LIGHT
ACCUMULATIONS POSSIBLE.
WITH DEWPOINTS EXPECTED TO GET INTO THE MID 30S OVER THE
SNOWPACK...AND THE SFC LOW COMING RIGHT OVERHEAD...MENTIONED PATCHY
FOG IN THE EAST SUN NIGHT AND MON MORNING.
.TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS FAIRLY QUIET TUESDAY THROUGH THE REMAINDER OF THE WORK WEEK.
MODELS DEPICTING A SERIES OF WEAK SHORTWAVES TO ROLL THROUGH DURING
THIS PERIOD...POSSIBLY BRINGING SOME FLURRIES OR LIGHT SNOW AT
TIMES. NEAR NORMAL TEMPS TUESDAY EXPECTED TO WARM TO A FEW DEGREES
ABOVE NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION/12Z TAFS/...
MAINLY MVFR CIGS OVER FAR SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN. LAKE BAND PUSHING SOUTH BUT STRONGEST RADAR RETURNS HAVE
BEEN STAYING OFF SHORE. AS LOW LEVEL FLOW BECOMES MORE EAST LAKE
EFFECT WILL EXPAND IN COVERAGE BUT SHOULD BE FAIRLY LIGHT...ALTHOUGH
SOME AREAS COULD SEE SOME VERY LIGHT ACCUMULATIONS. CIGS/VSBYS WILL
BE MAINLY MVFR.
THE LOW CLOUD SHIELD MAY ERODE SOMEWHAT FROM THE WEST...BUT THEN
WOULD TEND TO EXPAND AGAIN AS EAST FLOW INCREASES THE LOW LEVEL
MOISTURE.
IFR POTENTIAL LATER TONIGHT AS EAST/SOUTHEAST FLOW INCREASES.
&&
.MARINE...
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED LATE TONIGHT THROUGH
MONDAY NIGHT AS LOW PRESSURE MOVES EAST AND EXITS THE NORTHERN
PLAINS. BRISK SOUTH WINDS AND HIGH WAVES WILL PREVAIL SATURDAY
NIGHT INTO SUNDAY NIGHT. A COLD FRONT WILL THEN SHIFT THE WINDS TO
THE WEST FOR LATE SUNDAY NIGHT AND INTO MONDAY NIGHT. THE WINDS
WILL CONTINUE TO BE BRISK AND GUSTY AND SMALL CRAFT CONDITIONS
WILL LIKELY PERSIST FOR THIS TIME PERIOD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SUNDAY THROUGH FRIDAY...DDV
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1042 PM CST FRI JAN 20 2012
.UPDATE...
LAKE EFFECT SNOW BAND HAS NOT SHIFTED SOUTH YET AND IN FACT IS
DRIFTING NORTH. ADDED MILWAUKEE COUNTY BUT EXPECT BAND TO STAY
SOUTH OF THE CITY OF MILWAUKEE. LOOKS LIKE SNOWFALL RATES PER KMKX
DOPPLER RADAR ARE ON THE ORDER OF 0.50" PER HOUR.
LATEST HRRR HAS BAND STARTING TO SHIFT SOUTH IN ABOUT 5 HOURS SO
COULD END UP WITH 3-4 INCHES NEAR SOUTH MILWAUKEE AND OAK CREEK
BEFORE IT DOES SO.
NATURALLY WITH LAKE EFFECT UNCERTAINTY IS ALWAYS PRETTY HIGH AND
THE LATEST GUIDANCE ALL HAS A GENERAL HANDLE ON THE LOCATION AND
TIMING BUT EACH IS ABOUT A COUNTY OFF. MOST OF THE CURRENT
GUIDANCE SUGGESTS THAT THE BAND SHOULD BE OFFSHORE. 00Z NAM HOLDS
THE BAND IN MILWAUKEE COUNTY FOR A WHILE BEFORE SHIFTING SOUTH.
SINCE HRRR AND LOCAL 4KM RUN ARE SIMILAR...WILL GO WITH THAT
SCENARIO FOR NOW.
AT THIS POINT KENOSHA COUNTY ADVISORY MAY BE OVERDONE BUT THE BAND
SEEMS LIKELY TO SHIFT SOUTH EVENTUALLY AND KMKE TDWR HAS SHOWN
FLOW AT 925 MB GRADUALLY BACK TO MORE NORTHERLY WITH TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST SATURDAY FOR WIZ066-071-
072.
LM...NONE.
&&
$$
UPDATE...CRAVEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
1000 AM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
PREVIOUS...
CURRENTLY -SN HAS OVER SPREAD MOST OF NY FCA EXCPT N ADIRONDACKS
AND W NEW ENG...WHERE SNOW WILL BEGIN SHORTLY. OTHER THAN SOME
MINOR ADJUSTMENTS TO POPS/WX FCST REMAINS ON TRACK.
SURFACE WAVE MOVES FROM TN VLY TO NJ COAST TODAY. ISENTROPIC LIFT
IS MAIN MECHANISM PRODUCING UVM FOR SNOW TODAY. ALTHOUGH 500HPA
TROF AND ITS VORT MAX PASSING ACROSS US/CAN BORDER RGN SUPPORT
SOME UVM IN N PTNS OF FCA. OVERALL SNOW WILL BE GENERALLY LIGHT
ON ORDER OF 1-3 INCHES...EXCEPT IN SOUTHERN MOST AREAS WHERE
MODERATE AMOUNTS ARE EXPECTED (3-6IN) CLOSEST TO THE BEST
ISENTROPIC LIFT AND UVM.
MODELS (GEM/NAM/GFS/ECMWF) IN GOOD AGREEMENT FOR THIS PERIOD. QPF
A BLEND OF CURRENT FCST...HPC AND ALL 00UTC MODELS. GIVEN CONTRAST
ACROSS THERMAL RIBBON USED SNOW/LIQ RATIO OF 13. AS OF 230AM -SN
HAS REACHED A RME-BGM LINE. THIS WILL CONTINUE TO ADVANCE REACHING
HUD VLY BY 5-6AM.
SNOW WILL PERSIST INTO THE EARLY AFTN THEN END RAPIDLY FM NW TO SE
AS 500HPA TROF AND SFC LOW MOVES OFFSHORE CUTTING OFF ISENTROPIC
LIFT. OVERNIGHT 500HPA RIDGE BUILDS INTO NE USA..AND SFC HIGH
BUILDS OVER NEW ENG AND NY IN RESPONSE TO DIF ACVA. SKIES WILL
CLEAR DURING THE LATE AFTN AND ERLY EVENING...WITH CLR CONDS AND
FRESH SNOW IN MOST AREAS. SHOULD ALLOW FOR GOOD RAD COOLING AND
TEMPS TO PLUNGE TO NR NORMAL.
WINDS SHOULD BE LIGHT NE DURING THIS PERIOD EXCEPT ARND 10KTS IN S
PTNS OF FCA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS/VSBY IN -SN EXIST OVER MOST OF FCA. OVER NEXT FEW HRS MOST
AREAS FM ADIRONDACKS SOUTH WILL LOWER TO MVFR/IFR CIGS AND VSBY IN
-SN. IFR CONDS WILL BE MORE WIDESPREAD SOUTH. CONDS WILL IMPV DURING
THE AFTN BCMG MVFR FM NW TO SE...AND VFR BY EVENING. WINDS WILL BE
NORTH-NORTHEAST AROUND 5-10 KT TODAY.
OUTLOOK...
SAT NIGHT-SUN...VFR. NO SIG WX.
SUN NIGHT-MON MRNG...BCMG MVFR/IFR LATE. CHC -RA/-SN/-PL/-FZRA.
MON AFTN...MVFR/IFR. RA LIKELY.
MON NIGHT-TUE...VFR. SLIGHT CHC -SHRASN AND MVFR.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SNYDER/SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...SNYDER
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
938 AM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
MOISTURE WILL BE ON THE INCREASE IN THE SOUTH FLOW AHEAD OF THE
COLD FRONT. A MID-LEVEL SHORTWAVE TROUGH WILL ALSO BRING AN
INCREASE IN MOISTURE AND INSTABILITY. BELIEVE SHOWER COVERAGE WILL
INCREASE. THIS MORNING/S 88D VAD WIND PROFILE INDICATED WINDS OF
50 KNOTS AT 3000 FEET. THE LATEST RUC SHOWS THE SHEAR CONTINUING
DURING THE AFTERNOON. ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE
THUNDERSTORMS. THE NAM SHOWS SURFACE-BASED LI/S LOWERING TO AROUND
-2. THE THREAT TIMING APPEARS TO BE MAINLY BETWEEN 200 PM AND 800
PM BASED ON THE LATEST RUC MOISTURE CONVERGENCE PATTERN AND H85
JET. THE SHEAR APPEARS UNI-DIRECTIONAL SUPPORTING MAINLY A
STRAIGHT-LINE WIND THREAT...EXCEPT THERE COULD POSSIBLY BE MORE
DIRECTIONAL SHEAR ALONG A LINGERING BOUNDARY IN THE NORTH PART OF
THE FORECAST AREA. REPORTS UPSTREAM ALSO SUPPORT A HAIL THREAT.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE COLD FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT.
MOISTURE WILL BECOME SHALLOW BEHIND THE FRONT ON SUNDAY...BUT
ISENTROPIC LIFT MAY LEAD TO AREAS OF RAIN. MODELS CONTINUE TO
INDICATE THAT A LOW-LEVEL WEDGE PATTERN WILL SETUP SUNDAY AND
SUNDAY NIGHT. WITH SOME ISENTROPIC FLOW OVER THE WEDGE
POSSIBLE...CAN EXPECT TO HAVE SOME LIGHT RAIN AND DRIZZLE
THROUGHOUT THE DAY SUNDAY. THE TEMPERATURE GUIDANCE REMAINS TOO
WARM SUNDAY BECAUSE OF THE EXPECTED WEDGE PATTERN...AND THUS
CONTINUE TO UNDERCUT THE NUMBERS.
THE GFS SHOWED THE WEDGE FRONT TRYING TO LIFT NORTH OF THE
FORECAST AREA SUNDAY NIGHT. WEDGES SEEM TO STICK AROUND A LITTLE
LONGER THAN WHAT MODELS TYPICALLY FORECAST...SO WOULD EXPECT THE
WEDGE TO REMAIN SUNDAY NIGHT INTO MONDAY MORNING. EXPECTING A
CHANCE OF SHOWERS AND SOME POSSIBLE DRIZZLE SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ONLY MINOR CHANGES MADE TO THE LONG TERM THIS PACKAGE. ON MONDAY
THE WEDGE SHOULD ERODE IN ADVANCE OF THE NEXT APPROACHING COLD
FRONT. FORECASTED A CHANCE OF SHOWERS ASSOCIATED WITH THIS FRONT.
DRYING BEHIND THE FRONT APPEARED TO DOMINATE TUESDAY INTO
WEDNESDAY. KEPT A SMALL POP IN THE FORECAST BECAUSE OF TIMING
UNCERTAINTY ASSOCIATED WITH THE WARM ADVECTION PATTERN AHEAD OF
THE NEXT SYSTEM. THE GFS ENSEMBLES HAVE SHOWN A HIGH SPREAD IN THE
FAST FLOW. KEPT CHANCE POPS DURING THE REST OF THE EXTENDED
PERIOD. THE GFS SHOWED THE APPROACHING COLD FRONT REACHING THE
FORECAST AREA FRIDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
WARM FRONT MOVING NORTHWARD ACROSS THE CENTRAL SC MIDLANDS EARLY
THIS MORNING. ISENTROPIC LIFT OVER REGION LEADING TO LIGHT RAIN OR
LIGHT SHOWERS ACROSS THE REGION. SOME BRIEF MVFR CONDITIONS POSSIBLE
IN HEAVIER SHOWERS BEFORE 14Z THIS MORNING. AS THE WARM FRONT
CONTINUES TO MOVE NORTHWARD...LOW LEVEL WINDS INCREASE 1-2 KFT TO
220 AT 40 KNOTS AND LOW LEVEL WIND SHEAR IS POSSIBLE FROM 12Z-14Z
EARLY THIS MORNING. COMPOSITE REGIONAL RADAR INDICATING MORE SHOWERS
DEVELOPING OVER NORTHERN GA WHICH WILL MOVE INTO SC LATER THIS
MORNING. AFTER AROUND 18Z...WARM AIR ADVECTION IS EXPECTED TO ALLOW
STRONGER WINDS TO REACH THE SURFACE WITH GUSTY SOUTHWEST WINDS 15-25
KNOTS THUS DECREASING THE EFFECTIVE WIND SHEAR BUT INCREASING THE
POSSIBILITY OF LOW LEVEL TURBULENCE. SOME IFR-MVFR CONDITIONS ARE
POSSIBLE LATER DURING THE AFTERNOON AS A COLD FRONT APPROACHES AND
THE CHANCES FOR TSTMS INCREASE. A LINE OF THUNDERSTORMS OR POSSIBLY
A SQUALL LINE MAY DEVELOP BY LATE AFTERNOON/EARLY EVENING. SPC HAS
CAE FA OUTLOOKED FOR A SLIGHT RISK OF SEVERE STORMS TODAY WITH THE
MAIN THREAT BEING DAMAGING WINDS. CONVECTIVE ACTIVITY SHOULD
DIMINISH DURING THE EVENING HOURS. WINDS WILL BECOME MORE VARIABLE
AFTER 06Z SUNDAY AS THE COLD FRONT MOVES EAST OF OUR AREA AND HIGH
PRESSURE BEGINS TO BUILD IN FROM THE NORTH. MAINLY MVFR CONDITIONS
EXPECTED AFTER 06Z AS DRIZZLE ALONG WITH SOME PATCHY FOG DEVELOP
AFTER 06Z SUNDAY. CANNOT RULE OUT SOME IFR CONDITIONS AFTER 06Z BUT
CONFIDENCE IS LOW TO MENTION AT THIS TIME.
EXTENDED AVIATION OUTLOOK...FRONT TO SLOWLY PASS EARLY SUNDAY
MORNING...WITH APPEARANCE OF WEAK WEDGE BUILDING DOWN BEHIND IT ON
SUNDAY. THIS WILL PROVIDE POTENTIAL FOR LOW CLOUDINESS...POSSIBLY
IFR...EARLY SUNDAY MORNING...INTO SUNDAY NIGHT. THE NEXT FRONT WILL
MOVE THROUGH MONDAY PROVIDING A CHANCE OF SHOWERS...AND ASSOCIATED
RESTRICTIONS. NO SIGNIFICANT IMPACTS TO AVIATION ARE EXPECTED LATE
MONDAY INTO WEDNESDAY...AS HIGH PRESSURE BUILDS IN.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
556 AM CST SAT JAN 21 2012
.DISCUSSION...
ISSUED 330 AM CST SAT JAN 21 2012
WILL ALLOW THE WINTER WEATHER ADVISORY EXPIRE BY 4 AM SE OF LINCOLN.
MIXED PRECIPITATION HAS PASSED SE OF IL WITH 1008 MB LOW PRESSURE
OVER EASTERN KY. FORECAST CONCERN IS IF ANY CLEARING OCCURS THIS
AFTERNOON. THEN LOOKING AS A FAIRLY STRONG WX SYSTEM TO IMPACT THE
REGION SUNDAY NIGHT WITH SPC HAVE SLIGHT RISK NEAR SOUTHERN PARTS
OF RICHLAND AND LAWRENCE COUNTIES. NCEP FAVORED THE 00Z GFS MODEL
WITH THIS WEATHER SYSTEM WITH ABOVE AVERAGE CONFIDENCE AND WILL
FOLLOW SUITE. LEANED TOWARD THE 00Z ECMWF MODEL WITH MID/LATE WEEK
SYSTEM NEXT WEEK WITH SPLIT UPPER LEVEL FLOW PREVAILING THEN.
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
TRENDED CLOUDIER AND COOLER TODAY WITH FORECAST DUE TO EXTENSIVE
LOW CLOUD COVER ACROSS IL...MO INTO SE HALF OF IA AND LOW LEVEL
MOISTURE TRAPPED IN AN INVERSION. COULD BE A FEW PATCHES OF LIGHT
FREEZING DRIZZLE INTO MID MORNING OVER CENTRAL IL THOUGH HAVE NOT
SCENE ANY REPORTED NEARBY PAST FEW HOURS. TEMPS CURRENTLY RANGE
FROM THE MID TEENS FROM PEORIA NW TO THE MID 20S SE OF I-70. NORTH
WINDS 8 TO 16 MPH. 1027 MB HIGH PRESSURE OVER THE UPPER MS VALLEY
NEAR THE WI/IA/MN BORDER TO DRIFT EAST ACROSS LOWER MI THIS
AFTERNOON AND RIDGING INTO IL. THIS TO DECREASE LOW CLOUDS
OVER NORTHERN AREAS WHERE SKIES BECOME PARTLY SUNNY...WHILE SE IL
STAYS IN THE LOW CLOUDS TODAY. HIGHS MOSTLY IN THE 20S TODAY OVER
CENTRAL IL AND LOWER 30S IN SE IL.
SOUTHERLY FLOW TO SET UP TONIGHT AS HIGH PRESSURE STRENGTHENS TO
1033 MB AS IT MOVES INTO NEW ENGLAND AND MID ATLANTIC STATES BY
DAWN SUNDAY. LOWS PROBABLY REACHED THIS EVENING THEN MAY SNEAK UP
A FEW DEGREES OVERNIGHT AS LOW CLOUDS SPREAD BACK TO THE NORTH. A
FAIRLY STRONG STORM SYSTEM MOVING EAST INTO THE ROCKIES WILL HAVE
A DEEPENING STRONG LOW PRESSURE MOVING INTO THE UPPER MIDWEST
SUNDAY NIGHT AND SWEEP A COLD FRONT EAST THROUGH IL SUNDAY EVENING.
MILDER HIGHS IN THE 40S SUNDAY WITH LOWER 50S IN SE IL. HAVE
SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON...EXCEPT 30% CHANCE NW
OF THE IL RIVER. LIKELY CHANCES OF SHOWERS SUNDAY NIGHT AND EVEN
THUNDERSTORMS FROM I-55 EAST SUNDAY EVENING. WILL NEED TO WATCH SE
IL WITH SLIGHT RISK INTO SOUTHERN PARTS OF RICHLAND AND LAWRENCE
COUNTIES SUNDAY EVENING. VERY STRONG UPPER LEVEL DYNAMICS AND WIND
FIELDS AND DEEP MOISTURE WITH STORM. TEMPS COULD RISE A BIT AHEAD
OF THE COLD FRONT SUNDAY EVENING THEN FALL OVERNIGHT INTO MON
MORNING. MODELS HAVE TRENDED FURTHER NE WITH LIGHT MIXED
PRECIPITATION MONDAY WITH 1025 MB HIGH PRESSURE MOVING INTO THE TN
VALLEY BY SUNSET MONDAY AND HAVE ADJUST FORECAST ACCORDINGLY. FAIR
WEATHER EXPECTED MONDAY NIGHT THROUGH TUE NIGHT WITH NEARBY HIGH
PRESSURE.
LONG TERM...WEDNESDAY THROUGH FRIDAY NIGHT
EXTENDED MODELS SHOW A SPLIT UPPER LEVEL FLOW DURING MID AND LATE
WEEK OF NEXT WEEK AND HAVE TRENDED DRIER ON WED. STRONGER SOUTHERN
STREAM SYSTEM WITH CUTOFF LOW OVER NORTHERN MEXICO INTO TX WED-THU
KEEPS MOST OF ITS HEAVIER PRECIP SOUTH CENTRAL IL WHILE WEAKER
NORTHERN STREAM SHORT WAVE MOVES EAST ACROSS THE NORTHERN TIER STATES.
BEST CHANCE OF LIGHT PRECIPITATION APPEARS TO BE OVER SE IL WED
NIGHT AND SHOULD BE WARM ENOUGH FOR RAIN THERE. BEST CHANCES OF
PRECIPITATION APPEARS TO SHIFT EAST OF IL LATE NEXT WEEK AND TRENDED
TOWARD A DRIER FORECAST. GFS AND ECMWF MODEL BOTH HAVE TRENDED
DRIER DURING THIS TIME. TEMPS TO STAY ABOVE NORMAL DURING THIS
TIME FRAME.
HUETTL
&&
.AVIATION...
ISSUED 556 AM CST SAT JAN 21 2012...FOR THE 12Z TAFS
IFR STRATUS WILL CONTINUE THROUGH MID MORNING...WHEN THE CLOUD
LAYER SHOULD LIFT TO MVFR. PIREPS ARE SHOWING THE CLOUD LAYER AS
ABOUT 2K FT THICK...SO SOME CLEARING MAY DEVELOP AS MIXING DEEPENS
INTO THE DRY LAYER ABOVE 3K FT. THE NORTHWEST EDGE OF THE STRATUS
IS NOT PROGRESSING TO THE ESE AS YOU MIGHT EXPECT BEHIND A LOW
PRESSURE SYSTEM. SO CLEARING IS A TOUGH CALL. RUC AND HRRR MODELS
ARE SHOWING SOME DRYING WORKING INTO OUR AREA FROM THE
NORTHEAST...AS SURFACE WINDS INCREASE FROM THE NORTHEAST. SO CMI
AND DEC MAY BE THE EARLY TERMINAL SITES TO CLEAR OUT TO VFR THIS
AFTERNOON. PIA/BMI/SPI MAY BE DELAYED BY A FEW HOURS TO 20-21Z.
NOT HIGHLY CONFIDENT ON THE CLEARING SCENARIO...BUT WILL INCLUDE
SOME VFR FROM LATE AFTERNOON THROUGH MID EVENING...WHEN MVFR
CLOUDS RETURN ON SOUTHEAST WINDS.
WILL KEEP WINDS IN THE 9-13KT RANGE FOR MOST OF THE NEXT 24
HOURS. SOUTHEAST WIND SPEEDS WILL INCREASE TONIGHT AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE NEXT WEATHER SYSTEM.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
559 AM CST SAT JAN 21 2012
...UPDATE TO AVIATION...
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
SCT TO BKN MVFR CEILINGS WITH BASES OF 2200 FT TO 2800 FT WILL
CONTINUE ACROSS THE TAF SITE THIS MORNING. WEAK ISENTROPIC LIFT
ACROSS EASTERN KS THIS MORNING WILL SLOWLY DIMINISH AFTER 16Z
ALLOWING SKIES TO BECOME CLEAR. NORTHEAST WINDS OF 5 TO 10 KTS THIS
MORNING SWITCH TO THE SOUTHEAST AND SOUTH THROUGH THE AFTERNOON HOURS.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
420 AM MST SAT JAN 21 2012
.DISCUSSION...
420 AM MST SAT JAN 21 2012
MAIN FORECAST PROBLEM WILL BE THE WINDS THROUGH SUNDAY BUT MANY
OTHER CONCERNS ARE JUST BELOW THE WINDS. SATELLITE SHOWING AN
ACTIVE/PROGRESSIVE WAVE TRAIN FROM THE PACIFIC INTO THE WESTERN
ATLANTIC. BROAD UPPER TROUGH REMAINS IN PLACE OVER THE PACIFIC WITH
A STRONG SHORTWAVE TROUGH APPROACHING THE WEST COAST. ALSO BIG LOW
LEVEL TEMPERATURE GRADIENT SLIDING BACK AND FORTH ACROSS THE AREA.
AT JET LEVEL...EXTREMELY STRONG JET OVER THE EASTERN PACIFIC BEHIND
INCOMING TROUGH. BASED ON WHAT OBSERVATIONS ARE OUT THERE...THE
MODELS ARE UNDERDOING THE STRENGTH OF THE NEAR 200 KNOT JET. BASED
ON AVAILABLE DATA...THE GFS AND NAM LOOK TO HAVE THE BEST STRENGTH
BUT THE NAM/CANADIAN HAVE BEST ORIENTATION. OVER THE COUNTRY...THE
NAM AND CANADIAN HAVE THE BEST HANDLE ON THE JET THAT STARTED NEAR
OUR AREA LAST NIGHT. THE OTHER MODELS TENDED TO BE TOO FAR EAST.
SATELLITE AND UPPER AIR WOULD SUPPORT THE ECMWF/CANADIAN BEING THE
BEST AT MID LEVELS. MODELS TENDED TO BE TOO MOIST AT MID LEVELS
WITH THE CANADIAN AND UKMET DOING THE BEST. MODELS CONTINUING TO
HAVE TROUBLE WITH THE LOW LEVEL THERMAL FIELD. OVERALL THE UKMET AND
CANADIAN WAS DOING A LITTLE BETTER THAN THE GFS...ESPECIALLY WITH
THE POSITION OF THE COLD POOL TO OUR NORTH AND EAST.
TODAY/TONIGHT...NEWER GUIDANCE HAS COME IN A LITTLE STRONGER WITH
THE WINDS. MODELS SHOW LITTLE TO NO MIXING TODAY WITH LOUSY LOW
LEVEL LAPSE RATES. WHICH AM NOT ENTIRELY SURE ABOUT. INITIAL
QUESTION TO HELP WITH THAT WILL BE HOW MUCH CLOUD COVER WILL MOVE IN
TODAY. IMPRESSIVE CLOUD SHIELD OUT TO OUR WEST. THE BETTER MODELS IN
REGARDS TO THIS MOISTURE WOULD SAY THAT THE CLOUDS REALLY DO NOT
THICKEN UP UNTIL THIS AFTERNOON. HOWEVER...DESPITE THE LACK OF
MIXING WHAT MAY BE THE MAIN DRIVING FORCE BEHIND THESE WINDS COULD
THE TIGHTENING PRESSURE GRADIENT AND PRETTY HIGH 3 HOUR PRESSURE
FALLS THROUGH THE AFTERNOON. GOING BY WHAT LIMITED MIXING BUFKIT
SHOWS...WINDS LOOK TO REACH ADVISORY CRITERIA. IT WILL BE CLOSE BUT
CHOSE TO ISSUE A WIND ADVISORY FOR ALL BUT THE FAR EASTERN TWO
COUNTIES. ADVISORY MAY BE MARGINAL FOR THOSE EASTERN COUNTIES BUT
WILL BE PLAYING THIS ON THE SAFE SIDE.
MODELS HAVE HAD A HORRIBLE TIME WITH TEMPERATURE GRADIENT ACROSS THE
AREA. THICKENING CLOUD COVER WILL MAKE THIS EVEN MORE PROBLEMATIC.
LOW LEVEL THERMAL PROFILES CLUSTER AROUND A LITTLE WARMER
TEMPERATURES THAN WHAT IS IN THERE. CANADIAN SURFACE TEMPERATURE
MATCHES UP WELL WITH WHAT THE HRRR IS SHOWING. SO WARMED UP
TEMPERATURES SOME IN LINE WITH THOSE MODELS.
STRONG INCOMING SYSTEM BEGINS TO AFFECT THE AREA LATE TONIGHT.
DEEPER MOISTURE AND LIFT ALONG WITH DECENT LAPSE RATES COME INTO
THE WEST LATE. MORE MODEL QPF SHOWING QPF IN THIS AREA AND SEEMS
REASONABLE CONSIDERING THE LIFT AND INSTABILITY. QUESTION THEN
BECOMES PHASE. LOW LEVEL THERMAL GUIDANCE AND SOUNDING SHOW VERY
MILD OVERNIGHT TEMPERATURES IN ADVANCE OF THE SYSTEM. THE ONLY
PLACE THAT LOOKS TO BE NEAR FREEZING IS IN THE EAST WHERE
PRECIPITATION IS NOT EXPECTED AT THIS TIME. RAISED MINS ACROSS THE
REMAINDER OF THE AREA. CONSIDERING THE POSSIBILITY OF A LITTLE MORE
INTENSE PRECIPITATION AND BEING A LITTLE WARM...DID A RAIN AND SNOW
MIX IN THE FAR WEST WITH SPRINKLES TO THE EAST OF THERE.
SUNDAY/SUNDAY NIGHT...LEFT FRONT QUADRANT OF THE JET STARTS OUT OVER
THE EASTERN HALF OF THE AREA AT 12Z AND THEN IT QUICKLY MOVES EAST.
STRONG UPPER TROUGH MOVES THROUGH DURING THE DAY. BASED ON
SATELLITE...STRONG JET ASSOCIATED WITH THE SYSTEM...AND STRONG PV
ANOMALY INDICATED...BELIEVE THE MODELS ARE UNDERDOING THE STRENGTH OF
THE SYSTEM. COMBINATION OF STRONG LIFT/PV ANOMALY AND FAVORABLE
THETA-E LAPSE RATES...WILL BRING A GOOD CHANCE OF A LIGHT MEASURABLE
PRECIPITATION EVENT TO THE AREA. BASED ON THE PREVIOUS REASONING...
GEFS PROBABILITIES...AND LOCAL POP PROGRAM...RAISED POPS OVER THE
ENTIRE FORECAST AREA...ESPECIALLY IN THE EAST. DAY SHIFT WILL HAVE
TO LOOK AT RAISING THESE POPS EVEN MORE. PHASE REMAINS A PROBLEM.
MODELS DO NOT SHOW A LOT OF COLD AIR. IT IS POSSIBLE WITH THE MOST
INTENSE PRECIPITATION SNOW COULD MIX WITH THE RAIN IN THE MORNING.
AT THIS TIME KEPT THE MIXED PHASE IN THE MORNING WITH ALL RAIN IN
THE AFTERNOON.
HOWEVER...WHAT LOOKS TO BE THE MAIN STORY WILL ONCE AGAIN BE THE
WINDS. STRONG SUBSIDENCE BEHIND THE WAVE/EXITING PRECIPITATION
COMBINED WITH VERY GOOD LAPSE RATES AND 3 HOUR PRESSURE RISES
SHOULD BRING A HIGH END WIND ADVISORY EVENT TO THE ENTIRE AREA.
HOWEVER...STRONGEST 3 HOUR PRESSURE RISES ARE OUT AHEAD OF THE MAIN
SUBSIDENCE. WHAT IS CONCERNING IS THAT IF PARAMETERS CAN COME
TOGETHER A LITTLE BETTER...IT IS POSSIBLE THAT WARNING CRITERIA
COULD BE MET. DAY SHIFT WILL HAVE TO LOOK AT THIS AGAIN...AND CHOOSE
THE APPROPRIATE HIGHLIGHT. CHOSE TO GO SLIGHTLY BELOW THE GUIDANCE
WHICH WAS IN PRETTY CLOSE AGREEMENT. PRECIPITATION SHOULD BE DONE BY
THE NIGHT AND WILL PROBABLY COOL BELOW GUIDANCE.
MONDAY/MONDAY NIGHT...QUESTION WILL BE HOW MUCH TO WARM
TEMPERATURES. WILL HAVE A COLD START PLUS EXITING SURFACE HIGH AND
DEVELOPING LEE TROUGH WILL CAUSE THE WINDS TO BE MORE FROM AN
UPSLOPE DIRECTION. SO TRENDED SLIGHTLY COOLER THAN THAN GUIDANCE.
NEXT FRONT STARTS MOVING THROUGH DURING THE NIGHT AND MADE NO
CHANGES TO THE TONIGHT PERIOD.
BULLER
TUESDAY THROUGH FRIDAY...SHORTWAVE RIDGE BREAKS DOWN AS TROUGH OVER
GREAT BASIN SHIFTS EAST ACROSS THE INTERMOUNTAIN WEST. GUIDANCE IN
GENERAL AGREEMENT ON H5 CLOSED LOW DEVELOPING OVER NEW MEXICO
TUESDAY MORNING...WITH SHORTWAVE TROUGH KICKING EAST ACROSS THE CWA
BY 18Z TUESDAY. MOISTURE ISNT VERY IMPRESSIVE WITH THIS SYSTEM...
WITH CLOSED LOW KEEPING GULF MOISTURE MUCH FURTHER SOUTH. HOWEVER
THERE IS A NARROW WINDOW WHERE LARGE SCALE ASCENT AND LIMITED
MOISTURE ADVECT IS PRESENT OVER PARTS OF THE CWA. FOR NOW HAVE KEPT
SLIGHT CHANCE POPS ACROSS WESTERN LOCATIONS DURING THE DAY TUESDAY...
AND IN THE FAR EASTERN DURING THE EVENING. SHORTWAVE RIDGE DEVELOPS
ACROSS THE SW US WEDNESDAY AND THURSDAY AS TROUGH SHIFTS EAST...WITH
NW FLOW JUST NORTH OF THIS FEATURE OVER THE CWA. LEE TROUGH DEVELOPS
THURSDAY BENEATH THIS PATTERN WITH S/SW FLOW AT THE SURFACE
SUPPORTING A BRIEF RETURN TO TEMPS IN THE 50S/NEAR 60 THURSDAY
AFTERNOON. NW FLOW PERSISTS THROUGH FRIDAY...WITH SHORTWAVE
TROUGH PUSHING EAST TOWARDS THE PLAINS FRIDAY NIGHT. GUIDANCE IS ALL
OVER THE PLACE ON THE EXACT TRACK OF THIS FEATURE...SO NOT ENOUGH
CONFIDENCE TO ADD PRECIP AT THIS POINT.
DR
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
420 AM MST SAT JAN 21 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT
BOTH KGLD AND KMCK TERMINALS. SOUTHERLY WINDS WILL INCREASE THROUGH
THE MORNING AT BOTH TERMINALS AS LEE TROUGH STRENGTHENS THROUGH THE
DAY. AFTERNOON GUSTS UP TO 40KT ARE POSSIBLE AT KGLD...WITH GUSTS
AROUND 30KT AT KMCK. WHILE WINDS SHOULD DECREASE AT BOTH TERMINALS
AFTER 00Z...I STILL EXPECT GUSTY CONDITIONS TO CONTINUE THROUGH MOST
OF THE EVENING AT KGLD. WINDS WILL SHIFT TO THE WEST AROUND 09-10Z
AT BOTH TERMINALS AS SURFACE TROUGH SHIFTS EAST.
DR
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 10 AM MST /11 AM CST/ THIS MORNING TO 6 PM
MST /7 PM CST/ THIS EVENING FOR KSZ001>003-013>015-027>029-
041-042.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ013-027-041.
NE...WIND ADVISORY FROM 10 AM MST /11 AM CST/ THIS MORNING TO 6 PM
MST /7 PM CST/ THIS EVENING FOR NEZ079>081.
CO...WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM MST THIS EVENING
FOR COZ090>092.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ252>254.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
931 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE GULF OF MAINE TODAY. HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION SUNDAY AND MOVE EAST OF
THE AREA EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: HRRR MODEL STILL INDICATING NORTHERN EDGE OF SNOW WILL MOVE
ACROSS DOWNEAST THIS AFTERNOON WITH A PERIOD OF LIGHT SNOW SO WILL
KEEP POPS GOING FOR DOWNEAST TODAY. ANY SNOW ACCUMULATION WILL BE
LESS THAN AN INCH.
PREV DISC: LOW PRESSURE WILL TRACK SOUTH OF NEW ENGLAND TODAY. THE
PRECIPITATION FROM THIS SYSTEM IS ONLY EXPECTED TO EFFECT THE
SOUTH. HAVE USED A BLEND OF THE NAM12...GFS40 AND SREF FOR POPS.
WILL ADJUST THIS BLEND MANUALLY TO KEEP LOWER POPS FURTHER SOUTH.
HAVE USE A BLEND OF NAM12 AND GFS40 FOR WIND. HIGH PRESSURE WILL
BUILD IN FROM THE NORTHWEST SUNDAY. FOR TEMPERATURE AND DEW POINT
WILL USE GMOS AND ADJUST LOW TEMPERATURE LOWER SUNDAY MORNING TO
ACCOUNT FOR RADIATIONAL COOLING. FOR QPF HAVE BLENDED THE NAM12
AND GFS40.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A THAW LOOKS TO BE IN ORDER COME MONDAY W/LOW PRES MOVING THROUGH
THE WESTERN QUEBEC PROVINCE.
A NICE DAY IS IN STORE FOR SUNDAY W/A A GOOD DEAL OF SUNSHINE AS
HIGH PRES SETTLES RIGHT ACROSS THE STATE. TEMPERATURES WILL BE
WARMER THAN THEY WERE SATURDAY HITTING THE MID/UPPER TEENS NORTH
AND LOW TO MID 20S ACROSS THE CENTRAL AND DOWNEAST REGION. HIGH
PRES WILL SLIDE E SUNDAY NIGHT W/A RETURN FLOW FROM THE ESE
BEGINNING TO SETUP. HIGH CLOUDINESS IS SHOWN BY THE GFS AND THE
NAM TO MOVE ACROSS THE REGION SUNDAY NIGHT AS WAA BEGINS TO SET
UP. TEMPERATURES WILL DROP BACK IN THE EVENING AND THEN ARE SHOWN
TO LEVEL OFF BEFORE RISING EARLY MONDAY MORNING. ATTM, STAYED
CLOSE TO THE DAYCREW/S ASSESSMENT OF SINGLE NUMBERS ACROSS THE
NORTHERN AND WESTERN SECTIONS AND LOW TO MID TEENS FOR THE CENTRAL
AND DOWNEAST REGIONS. THIS WILL NEED TO BE LOOKED AT AGAIN AS ANY
PROLONGED CLEARING WILL ALLOW FOR TEMPERATURES TO FALL OFF MORE
BEFORE LEVELING OFF.
INCREASING CLOUDS FOR MONDAY W/A SSE FLOW SETTING UP AND MOISTURE
GETTING PULLED NORTHWARD. STRATUS LOOKS LIKE IT COULD ADVECT IN
W/THIS SETUP. ECMWF HOLDS ON TO LLVL COLD AIR LONGER W/DAMMING
ACROSS THE ENE SECTIONS OF THE CWA. THE NAM AND THE CANADIAN
HEMISPHERIC INDICATE THIS TO BE THE CASE AS WELL. THE GFS BREAKS
DOWN THE DAMMING QUICKER. THEREFORE, DECIDED TO CUT BACK MAXES ON
MONDAY W/THE SETUP PLUS WARMING TENDS TO HOLD BACK A BIT W/A SE
FLOW GETTING STARTED(HISTORICALLY SPEAKING). PRECIP CHANCES WERE
HELD BACK SOME W/RIDGE HOLDING IN LONGER. LOOKS LIKE SOME MIX OF
RAIN/SNOW AND SLEET INITIALLY LATE MONDAY ACROSS THE NORTH AND
WEST W/RAIN OVER THE DOWNEAST AND POINTS SOUTH. TEMPERATURES WILL
CONTINUE TO SLOWLY RISE MONDAY NIGHT AND THIS WILL BE ADDRESSED
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE MAIN CHALLENGE THIS TERM WILL BE TEMPERATURES AND PRECIP TYPE
EARLY IN THE TERM.
OCCLUSION IS SHOWN BY THE LONG RANGE GUIDANCE INCLUDING THE
CANADIAN HEMISPHERIC TO LIFT NORTHWARD MONDAY NIGHT AND SWING
ACROSS THE REGION ON TUESDAY. THE NAM/ECMWF SHOW A WEAK LOW
DEVELOPING ON THE OCCLUSION AND MOVING ACROSS EASTERN MAINE. THIS
COULD ENHANCE PRECIP AND POSSIBLY CUT OFF SIGNIFICANT WARMING
WHILE THE CANADIAN HEMISPHERIC HINTS AT SOMETHING SIMILAR BUT IS
FURTHER WEST WHICH WOULD ALLOW FOR MORE WARMER AIR TO BE PULLED
NORTHWARD. THE GFS AND ITS ENSEMBLE MEAN KEEP THE OCCLUSION
SWEEPING THROUGH THE REGION ON TUESDAY. DAYCREWS POPS LOOKED GOOD
AND MODIFICATIONS MADE ONLY FOR PLACEMENT AND BROUGHT THE VALUES
UP SOME BUT STILL IN THE LIKELY TO CATEGORICAL RANGE. SOME SLEET
AND RAIN POSSIBLE ACROSS THE FAR NORTH EARLY MONDAY EVENING BUT
THE COLUMN SHOULD BE WARM ENOUGH TO ALLOW FOR RAIN. AN INTERESTING
NOTE IS THAT THE HEMISPHERIC GUIDANCE SHOWS 40S AND 50S TUESDAY
AFTERNOON. THIS IS THE ONLY GUIDANCE THAT IS SHOWING THIS TO BE
THE CASE. A BLEND OF THE GMOS AND GFS WAS USED FOR THE TEMPERATURES
WHICH INDICATE A WARMER SCENARIO FOR TUESDAY W/TEMPERATURES
HITTING THE MID AND UPPER 30S NORTH AND WEST AND 40S CENTRAL AND
DOWNEAST. THE FRONT CLEARS THE REGION BY TUESDAY EVENING W/THE
GRADUAL COOL DOWN AND WHATEVER PRECIP IS LEFTOVER TRANSITIONING TO
SNOW SHOWERS MAINLY NORTH & WEST. HELD BACK THE COOLING FOR ABOUT
6 HRS AS PAST EVENTS SIMILAR TO THIS SHOW MODELS TO BE TOO FAST
W/BRINGING THE COLDER AIR BACK IN BEHIND THE OCCLUSION. UPPER TROF
WILL NEED TO MOVE THROUGH FOR THAT TO HAPPEN. GMOS/GFS TEMPERATURES
WERE BLENDED FOR TUESDAY NIGHT AS WELL.
THE ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA ON
WEDNESDAY W/MUCH COLDER TEMPERATURES FOR MID TO LATE WEEK AS
ADVERTISED BY THE GFS AND ECMWF. GMOS WAS USED FROM WEDNESDAY
ONWARD BUT PULLED BACK POPS TO BELOW 20% THURSDAY INTO FRIDAY
W/HIGH PRES BUILDING ACROSS THE REGION. ECMWF BRINGS A LOW ACROSS
THE GULF OF MAINE LATE NEXT FRIDAY W/AN INVERTED TROF HANGING BACK
ACROSS THE REGION SIMILAR TO THIS PASS EVENT YESTERDAY(FRIDAY1/20).
THIS WOULD MEAN POTENTIAL SNOW FOR THE CWA. THE ECMWF IS THE ONLY
GUIDANCE SHOWING THIS AS THE GFS AND ITS ENSEMBLES SHOW THE LOW TO
DEVELOP WELL SOUTH OF THE CWA. STILL PLENTY OF TIME TO LOOK AT
THIS AS THIS IS DAY 7!.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MAINLY VFR CONDITIONS TODAY AND TONIGHT EXCEPT FOR A
PERIOD OF MVFR IN LIGHT SNOW ACROSS DOWNEAST TERMINALS LATE
MORNING INTO EARLY AFTERNOON.
SHORT TERM: VFR FOR SUNDAY AND THEN POTENTIAL FOR MVFR/IFR ON
MONDAY W/SSE FLOW SETTING UP W/MOISTURE GETTING PULLED IN FROM THE
ATLC OCEAN. MONDAY NIGHT INTO TUESDAY LOOK TO BE IFR AND EVEN LIFR
AT LEAST EARLY IN THE DAY. LLWS ALSO A POSSIBILITY EARLY TUESDAY.
&&
.MARINE...
NEAR TERM: AS LOW PRESSURE MOVES SOUTHEAST OF THE WATERS, MAY
HAVE A PERIOD OF SCA WINDS ON THE BACK SIDE OF THE LOW PRESSURE
TONIGHT MAINLY OVER OUR OUTER WATERS.
SHORT TERM: SCA CONDITIONS BY MONDAY W/POTENTIAL FOR A BRIEF
PERIOD OF GALES EARLY TUESDAY W/THE OCCLUSION. USED THE NAM12 AND
GFS THROUGH EARLY TUESDAY WHICH SUPPORTS GUSTS HITTING 35+ KTS
FROM 12-18Z TUESDAY AS LLVL JET OF 50 KTS IS SHOWN TO PASS OVER
THE WATERS. HELD ONTO THE DAYCREWS WAVE HEIGHTS OF INCREASING SEAS
TO 10-13FT BY TUESDAY W/SSE FLOW. FOLLOWED WNAWAVE FROM TUESDAY
NIGHT INTO WEDNESDAY SHOWING A DECREASING TREND IN SEAS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...FOSTER/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...FOSTER/MIGNONE
MARINE...FOSTER/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
951 AM EST SAT JAN 21 2012
.SYNOPSIS...
WHATS LEFT OF THE WINTRY MIX WILL END BY NOONTIME AS LOW PRESSURE
EXITS EAST PAST THE WEST VIRGINIA MOUNTAINS. HIGH PRESSURE, COMING
EAST FROM WISCONSIN, WILL PROVIDE A DRY BREAK THIS AFTERNOON INTO
SUNDAY EVENING. A COLD FRONT, COMING EAST FROM THE ROCKIES, WILL
THEN BRING RAIN SHOWERS LATE SUNDAY NIGHT AND MONDAY, FOLLOWED
SCATTERED SNOW SHOWERS LATE MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PER RECENT SURFACE AND RADAR DATA HAVE FORECASTED A SLIGHTLY
FASTER END OF THE WINTRY MIX. HENCE HAVE DROPPED ADDITIONAL
COUNTIES FROM WINTER WEATHER HEADLINES, ONLY LEAVING THE MOUNTAINS
WITH HEADLINES UNTIL 12 PM.
PER RECENT SATELLITE DATA AND HRRR MODEL OUTPUT, HAVE FORECASTED
THINNING CLOUDS IN WAKE OF EXITING LOW PRESSURE SYSTEM. HAVE
MAINTAINED A SLOW DECREASE IN CLOUD COVERAGE AS NAM MODEL PROFILES
SUGGEST STRATOCUMULUS CAN REMAIN IN A THIN SATURATED LAYER BENEATH
A STRENGTHENING SUBSIDENCE INVERSION NEAR 4 KFT AGL.
HAVE CUT TEMPERATURE INCREASE THIS AFTERNOON, INFLUENCED BY RECENT
HRRR AND GFS LAMP MODEL OUTPUT, TO PRETTY MUCH MAINTAIN STEADY
TEMPERATURES THIS AFTERNOON. PART OF THIS IS DUE TO COLD ADVECTION
AND LINGERING CLOUDS, AND PART DUE TO REFRIGERATING, REFLECTIVE
EFFECTS OF FRESH SNOW AND ICE COVER.
FOR TONIGHT, EXPECT CLOUDS TO DECREASE. HAVE LOWERED LOW
TEMPERATURES DUE TO EXPECTED INCREASE IN RADIATIVE COOLING ABOVE
FRESH SNOW AND ICE COVER.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW HIGH PRESSURE, COMING
EAST FROM THE PLAINS, WILL PROVIDE A DRY BREAK INTO SUNDAY
EVENING. THEN EXPECT LOW PRESSURE, MOVING EAST ACROSS SOUTHERN
CANADA, TO DRIVE A COLD FRONT THROUGH THE UPPER OHIO VALLEY MONDAY
AFTERNOON. THE FRONTAL BAND OF SHOWERS SHOULD SPREAD EASTWARD
THROUGH THE AREA, STARTING LATE SUNDAY NIGHT.
FORECASTED TEMPERATURES, USING BLEND OF NAM AND GFS MOS, TO WARM
ABOVE FREEZING SUNDAY AND STAY ABOVE FREEZING INTO LATE MONDAY.
HIGHS MONDAY CAN BE 10 DEGREES WARMER THAN NORMAL.
PREFRONTAL SOUTHEAST WINDS MAY GUST OVER 30 MPH DOWNWIND FROM THE
MOUNTAINS SUNDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A LOW PRESSURE SYSTEM WILL EXIT THE GREAT LAKES REGION AND MOVE INTO
SOUTHERN QUEBEC BY TUESDAY. SHOWERS WILL TAPER OFF TUESDAY AND COULD
CHANGE OVER TO SCATTERED SNOW SHOWERS BEFORE ENDING IN THE
AFTERNOON. A RIDGE OF HIGH PRESSURE SHOULD PROVIDE DRY WEATHER ON
WEDNESDAY.
MEDIUM RANGE MODELS SHOW A NORTHERN BRANCH SHORT WAVE TROUGH MOVING
EAST INTO THE GREAT LAKES REGION BY THURSDAY. MEANWHILE...A SOUTHERN
BRANCH CLOSED LOW MEANDERS GENERALLY EASTWARD ACROSS TX AND INTO THE
LOWER MS VALLEY LATE IN THE WEEK. MODELS DIFFER ON EVOLUTION AND
TRACK OF ASSOCIATED SURFACE LOWS THURSDAY INTO FRIDAY. OUR PLAN IS
TO STICK WITH HPC GUIDANCE WITH CHANCE POPS BEGINNING WEDNESDAY
NIGHT AND CONTINUING INTO FRIDAY.
TEMPERATURES ARE FORECAST TO REMAIN GENERALLY BETWEEN 5 AND 10
DEGREES ABOVE NORMAL DURING THE EXTENDED PERIOD.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
VISIBILITIES HAVE IMPROVED TO MVFR IN LIGHT FOG IN WAKE OF ENDING
PRECIPITATION, AND WILL BECOME UNRESTRICTED THIS AFTERNOON.
POST SYSTEM COOLING, COMBINED WITH SUBSIDENCE ALOFT, WILL MAINTAIN
A STRATOCUMULUS DECK INTO EARLY EVENING. CEILINGS WILL SLOWLY LIFT
FROM IFR LEVELS TO MVFR LEVELS THIS AFTERNOON.
SURFACE WINDS WILL BE FROM THE NORTH NEAR 10 KTS THIS AFTERNOON,
THEN BECOME NORTHEAST NEAR 5 KTS TONIGHT.
EXPECT VFR LATE TONIGHT, BUT NAM MODEL PROFILES SHOW STRONG
SURFACE INVERSION DUE TO RADIATIVE EFFECTS OVER FRESH SNOW AND ICE
COVER. SO HAVE SOME CONCERN OF EARLY MORNING FOG WITH RESTRICTIONS
DEVELOPING, BUT NOT CONFIDENT TO INCLUDE IN TAF FORECAST.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
VFR INTO EARLY SUNDAY NIGHT. COLD FRONTAL BANDS OF RAIN SHOWERS
WITH LIKELY RESTRICTIONS LATE SUNDAY NIGHT INTO MONDAY NIGHT. POST
FRONTAL SCATTERED SNOW SHOWERS MAY CAUSE LINGERING RESTRICTIONS
INTO TUESDAY. VFR WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL NOON EST TODAY FOR MDZ001.
OH...NONE.
PA...WINTER STORM WARNING UNTIL NOON EST TODAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
713 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE CENTERED OVER THE TENNESSEE VALLEY WILL TRACK EAST
TODAY AND MOVE VERY SLOW THROUGH THE MID ATLANTIC REGION. THE
ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST LATE THIS AFTERNOON AND
EVENING AS STRONG HIGH PRESSURE BUILDS SOUTH FROM NEW ENGLAND
OVERNIGHT INTO SUNDAY. A STRONGER COLD FRONT WILL AFFECT THE AREA
ON MONDAY...FOLLOWED BY HIGH PRESSURE BUILDING OVER THE SOUTHEAST
STATES TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FCST TO ADD WINTER WX ADSY FOR SOME OF THE NW
COUNTIES...AS AREA OF MODERATE PRECIPITATION IS OVERSPREADING THIS
AREA...AND SHOULD COINCIDE WITH TEMPS 32 F OR COLDER FOR ABOUT 3
HRS. USING LATEST RUC SFC- WET BULB TEMPERATURES SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT OBS...LOW LEVEL COLD AIR IS VERY SHALLOW...SUCH
THAT EVEN 1000-850 MB THICKNESSES ARE VERIFYING TOO WARM.
OTHERWISE...AREAS FARTHER TO THE SE OF THE ADVSY SHOULD ENCOUNTER
JUST RAIN FOR THE REST OF THE DAY...6 AM OBS SHOW DEW PT AT 34 F
AT RIC...SO THAT EVAPORATIVE COLUMN COOLING WILL NOT LOWER THE
TEMPS AS THEY DID LAST EVENING...SOME SPOTTY -FZRA MAY BE
POSSIBLE OVER EXTREME NW PORTIONS OF THE COUNTIES BORDERING THE
ADSY BUT ANY ACCUMULATION IS NOT LIKELY...AS SFC TEMPS SHOULD BE
ABOVE FREEZING SHORTLY.
LATER TODAY...RA/SHRA SHOULD COVER ALL AREAS BY LATE MORNING OR EARLY
AFTN. SOUTH OF THE BOUNDARY...ADDED ISO TSTMS FOR THE AFTN IN SE
VA/NE NC WHERE TEMPS RISE INTO THE UPR 50S TO MID 60S W/ DEW PTS
IN THE 50S. CURRENT AREA OF CONVECTION OVER KY/TN WILL LIKELY
BREAK APART WHEN IT INTERACTS W/ THE MTNS BUT MAY RE- GENERATE
THIS AFTN. ONLY MINIMAL INSTABILITY BUT THERE IS DECENT SHEAR SO
AN ISO STRONGER STORM IS POSSIBLE/MAIN THREAT BEING STRONG WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...MODELS AGREE THAT N/NE FLOW WILL OVERSPREAD THE ENTIRE
CWA BY 00Z...AS SFC LOW PUSHES OFF THE NC COAST. STILL LOTS OF LOW
LEVEL MOISTURE...BUT MID LEVEL DRYING FROM THE NORTH SHOULD BRING
AN END TO MOST OF THE PRECIP BETWEEN 00-03Z EXCEPT IN NE NC WHERE
IT LINGERS A FEW HRS LONGER. WV SATELLITE SUGGEST STRONG AREA OF
MID-UPPER CONFLUENCE OVER HUDSON BAY WILL SLIDE SE...ALLOWING WITH
A 1035 MB SFC HIGH TO BUILDING INTO ERN NY STATE/NEW ENGLAND. COLD
AIR FILTERS SOUTH ONCE AGAIN...BUT PRETTY GOOD CONSENSUS THAT
THIS WILL HOLD OFF UNTIL AFTER BULK OF PRECIP ENDS...I.E. PRECIP
ENDS BEFORE PTYPE CONCERNS BECOME A MAJOR ISSUE. FOR NOW WILL
MENTION POTENTIAL FOR FREEZING DRIZZLE ACRS NRN ZONES BEGINNING
AFTER ABOUT 03Z. LOWS IN THE UPR 20S NORTH...UPR 30S S.
SUN/SUN NIGHT...LOOKS TO BE A COLD DAY ON SUNDAY WITH NE FLOW. ONLY
CONCERN WOULD BE FOR FREEZING DRIZZLE IN THE MORNING OVER CENTRAL
VA...INCLUDING METRO RICHMOND AND AREAS ON NW AS LOW LEVELS REMAIN
BELOW CRITICAL THRESHOLDS FOR FROZEN PRECIP. VERY DRY ALOFT
HOWEVER...SO THIS WOULD BE NOTHING MORE THAN FREEZING DRIZZLE...WILL
MAKE AN HWO MENTION FOR NOW. SHOULD BE WARM ENOUGH FOR JUST -RADZ
BY AFTN (EXCEPT COULD BE CLOSE IN THE COLDER FAR NW ZONES. DOUBT
WE`LL SEE ANY BREAKS IN THE CLOUD COVER AS LOW LEVEL INVERSION
WILL BE DIFFICULT TO MIX OUT...PERHAPS A FEW PEEKS OF SUN IN THE
MORNING OVER THE FAR NORTH CLOSEST TO THE SFC HIGH. BREEZY
CONDITIONS ALONG THE COAST. FAVOR THE COLDER MET NUMBERS FOR
HIGHS...BASED ON LIMITED MIXING AND A LOW OVC...HIGHS RANGING FROM
THE UPPER 40S FAR SE VA/NE NC...MID- UPPER 30S NW ZONES. TEMPS
RISE OVERNIGHT SUNDAY NIGHT...AS SFC HIGH OVER NEW ENGLAND
RETREATS OFF TO THE NE...FOLLOWED BY SIGNIFICANT WARM-UP ON MON
AHEAD OF THE NEXT SYSTEM. FAVOR THE WARMER MAV VALUES ON MON W/
SSW FLOW BY LATE MORNING AFTN...HIGHS GENLY IN THE UPR 50S NW
(WHERE PRECIP COMES IN EARLIER) TO THE MID- UPR 60S SE. CHC TO
LIKELY POPS FOR SHOWERS ALL AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A SERIES OF WAVES WILL PASS NORTH OF THE FA DURING THE LONG TERM
PERIOD DRAGGING COLD FRONTS AND PERIODS PRECIP THROUGH THE AREA.
RAIN WILL BEGIN TO IMPACT THE AREA MONDAY AS AN UPPER LEVEL WAVE
PASSES OVER NORTHERN MICHIGAN. THE ASSOCIATED COLD FRONT CROSSES THE
AREA BRINGING A PERIOD OF RAIN AND A WIND SHIFT FROM THE S TO N. THE
MODELS VARY A BIT WITH THE STRENGTH OF THE SYSTEM...AND HAVE LEANED
TOWARD THE WEAKER ECMWF. BUT...IF THE GFS VERIFIES THERE COULD BE A
COUPLE TSTMS THAT DEVELOP IN NE NC AND SE VA. BENIGN WX PREVAILS AS
HIGH PRESSURE BUILDS OVER THE AREA TUESDAY NIGHT AND SLIDES OFF THE
COAST BY THURSDAY EVENING. THE NEXT SYSTEM LOOKS TO IMPACT THE AREA
FRIDAY MORNING AS A WARM FRONT BRINGS RAIN INTO THE AREA...FOLLOWED
BY A COLD FRONT THAT WILL BRING ANOTHER ROUND OF RAIN LATE FRI/EARLY
SAT. AGAIN THERE IS A BIT OF DISAGREEMENT WITH THE MODEL TIMING OF
THIS EVENT. THE ECMWF PROGRESSES THE UPPER LEVEL SYSTEM EAST MUCH
MORE QUICKLY THAN THE GFS. BEING THIS FAR OUT IN THE FORECAST...JUST
TRIED TO BLEND THE TIMING OF THE SCENARIOS TOGETHER.
EXPECT A BIT OF A ROLLER COASTER AS FAR AS TEMPS GO DURING THE
PERIOD. WITH THE APPROACH THE SYSTEM MONDAY...EXPECT HIGHS IN THE
MID 60S NORTH TO UPPER 60S SOUTH. AS THE FRONT CLEARS THE AREA
MILDER TEMPS WILL PREVAIL WITH HIGHS IN THE MID 50S TO 60 FOR TUES
AND WED. A WARMER DAY FOLLOWS ON THUR AS WINDS TURN SOUTH AHEAD OF
THE NEXT FRONT. LOWS WILL BE IN THE LOW 40S TUES...FALLING TO THE
LOW AND MID 30S FOR WED AND THUR...WARMING INTO THE MID 40S FOR FRI
AND SAT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
ONGOING LIGHT TO MOD PCPN THIS MORNING IN ASSOCIATION WITH WEAK
ISENTROPIC LIFT. MVFR/TEMPO IFR CONDS ACROSS ALL BUT FAR SE
TERMINALS AS OF 7A. CONDITIONS DETERIORATING AS EXPECTED OVER FAR
NORTHERN ZONES...WITH IFR CONDS EXPECTED AT NORTHERN TERMINALS THROUGHOUT
THE DAY. PCPN REMAINS IN FORM OF VERY LIGHT FZRA N OF
KRIC/KSBY...AND WL NEED TO KEEP AN EYE ON TRENDS AS THE MORNING
PROGRESSES. HV ACCOUNTED FOR PERIODS OF RA/DZ ACROSS SITES THIS
MORNING...WITH DETERIORATING CONDS AS NEXT SLUG OF OVERRUNNING
MOISTURE ARRIVES FROM THE WEST.
S/SE WINDS VEER TOWARDS THE W/SW LATER THIS MORNING AS A WARM
FRONT LIFTS ACROSS THE AREA, BEFORE TURNING BACK TO THE NORTH LATE
THIS AFTN AS LOW PRESSURE TRACKS TO OUR WEST/NORTHWEST, PUSHING A
COLD FRONT THROUGH THE AREA TONIGHT.
OUTLOOK: ALTHOUGH PCPN IS EXPECTED TO END TONIGHT...WIDESPREAD
IFR IS FCST TO CONTINUE SUNDAY AND INTO MONDAY. A CHANCE FOR RAIN
RETURNS WITH THE NEXT COLD FRONT PASSAGE ON MONDAY WITH IMPROVING
CONDITIONS BEHIND THE FRONTAL PASSAGE FOR TUESDAY THROUGH MIDWEEK.
&&
.MARINE...
HV UPDATED SCA IN BAY TO BEGIN WITH 7AM ISSUANCE. WINDS TO
MARGINAL/LOW END SCA FOR A FEW HOURS THIS MORNING BEFORE
DIMINISHING BRIEFLY AS WINDS BECOME W/SW. WINDS RAMP BACK UPWARDS
BEHIND FRONTAL PASSAGE THIS AFTN.
PREV DISCUSSION...
LATEST WX ANALYSIS/OBSERVATIONS SHOWS WARM FRONT DRAPED JUST SOUTH
OF THE WATERS THIS MORNING...RESULTING IN E-SE WINDS AS OF 12Z.
WINDS WILL CONTINUE TO VEER TOWARDS THE S-SW THIS MORNING AS WARM
FRONT PUSHES NORTH (WHILE INCREASING IN SPEED (TO AVG 15-20 KT))
THROUGH MIDDAY. WARM FRONT WILL PUSH NORTH OF THE WATERS THIS
MORNING AND MEANDER JUST NORTH OF THE WATERS EARLY THIS AFTN...BEFORE
BEING SHUNTED BACK S ACROSS THE WATERS LATE THIS AFTN INTO
TONIGHT AS SFC LOW PRES MOVING ACROSS NC PUSHES OFFSHORE. RESULTANT
WIND DIRECTION WILL VEER AROUND TO THE N-NE BEHIND THE FRONTAL
PASSAGE. PRESSURE GRADIENT WILL TIGHTEN SIGNIFICANTLY AS SFC HIGH
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SLIDES ACROSS NORTHEAST
US. THIS WILL RESULT IN WINDS RAMPING UPWARDS INTO SCA CRIT RANGE
(20 TO 25 KT)...WITH HIGHEST WINDS EXPECTED AFTER 00Z/7PM TONIGHT
THROUGH SUN MRNG. WINDS BEGIN TO DIMINISH AS GRADIENT SLACKENS SUN
AFTN...THOUGH RMN FM THE NE.
ONLY MINOR CHANGE TO SCA WAS TO RUN THROUGH SUN AFTN OVER THE BAY,
AND THROUGH LATE SUNDAY NIGHT OVER THE COASTAL WATERS.
WINDS BECOME LIGHT SUNDAY NIGHT INTO EARLY MONDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVERHEAD, BUT RAMP UPWARDS GRADUALLY MONDAY AFTN
AHEAD OF THE NEXT FRONTAL SYSTEM WHICH APPROACHES FROM THE W MONDAY.
WINDS WL INITIALLY BE HIGHER OVER LAND MONDAY AFTN, BUT EVENTUALLY
EXPECT ANOTHER ROUND OF SCA CONDITIONS BY MONDAY NIGHT. CONDITIONS
IMPROVE BACK BELOW SCA CRITERIA ON TUE AS HIGH RPESSURE REBUILDS
INTO THE REGION FROM THE WEST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
VAZ048-049-062>064.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST SUNDAY FOR ANZ630>632-634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 3 PM EST SUNDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...LKB
LONG TERM...DAP
AVIATION...MAM
MARINE...MAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
602 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE CENTERED OVER THE TENNESSEE VALLEY WILL TRACK EAST
TODAY AND MOVE VERY SLOW THROUGH THE MID ATLANTIC REGION. THE
ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST LATE THIS AFTERNOON AND
EVENING AS STRONG HIGH PRESSURE BUILDS SOUTH FROM NEW ENGLAND
OVERNIGHT INTO SUNDAY. A STRONGER COLD FRONT WILL AFFECT THE AREA
ON MONDAY...FOLLOWED BY HIGH PRESSURE BUILDING OVER THE SOUTHEAST
STATES TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FCST TO ADD WINTER WX ADSY FOR SOME OF THE NW
COUNTIES...AS AREA OF MODERATE PRECIPITATION IS OVERSPREADING THIS
AREA...AND SHOULD COINCIDE WITH TEMPS 32 F OR COLDER FOR ABOUT 3
HRS. USING LATEST RUC SFC- WET BULB TEMPERATURES SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT OBS...LOW LEVEL COLD AIR IS VERY SHALLOW...SUCH
THAT EVEN 1000-850 MB THICKNESSES ARE VERIFYING TOO WARM.
OTHERWISE...AREAS FARTHER TO THE SE OF THE ADVSY SHOULD ENCOUNTER
JUST RAIN FOR THE REST OF THE DAY...6 AM OBS SHOW DEW PT AT 34 F
AT RIC...SO THAT EVAPORATIVE COLUMN COOLING WILL NOT LOWER THE
TEMPS AS THEY DID LAST EVENING...SOME SPOTTY -FZRA MAY BE
POSSIBLE OVER EXTREME NW PORTIONS OF THE COUNTIES BORDERING THE
ADSY BUT ANY ACCUMULATION IS NOT LIKELY...AS SFC TEMPS SHOULD BE
ABOVE FREEZING SHORTLY.
LATER TODAY...RA/SHRA SHOULD COVER ALL AREAS BY LATE MORNING OR EARLY
AFTN. SOUTH OF THE BOUNDARY...ADDED ISO TSTMS FOR THE AFTN IN SE
VA/NE NC WHERE TEMPS RISE INTO THE UPR 50S TO MID 60S W/ DEW PTS
IN THE 50S. CURRENT AREA OF CONVECTION OVER KY/TN WILL LIKELY
BREAK APART WHEN IT INTERACTS W/ THE MTNS BUT MAY RE- GENERATE
THIS AFTN. ONLY MINIMAL INSTABILITY BUT THERE IS DECENT SHEAR SO
AN ISO STRONGER STORM IS POSSIBLE/MAIN THREAT BEING STRONG WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...MODELS AGREE THAT N/NE FLOW WILL OVERSPREAD THE ENTIRE
CWA BY 00Z...AS SFC LOW PUSHES OFF THE NC COAST. STILL LOTS OF LOW
LEVEL MOISTURE...BUT MID LEVEL DRYING FROM THE NORTH SHOULD BRING
AN END TO MOST OF THE PRECIP BETWEEN 00-03Z EXCEPT IN NE NC WHERE
IT LINGERS A FEW HRS LONGER. WV SATELLITE SUGGEST STRONG AREA OF
MID-UPPER CONFLUENCE OVER HUDSON BAY WILL SLIDE SE...ALLOWING WITH
A 1035 MB SFC HIGH TO BUILDING INTO ERN NY STATE/NEW ENGLAND. COLD
AIR FILTERS SOUTH ONCE AGAIN...BUT PRETTY GOOD CONSENSUS THAT
THIS WILL HOLD OFF UNTIL AFTER BULK OF PRECIP ENDS...I.E. PRECIP
ENDS BEFORE PTYPE CONCERNS BECOME A MAJOR ISSUE. FOR NOW WILL
MENTION POTENTIAL FOR FREEZING DRIZZLE ACRS NRN ZONES BEGINNING
AFTER ABOUT 03Z. LOWS IN THE UPR 20S NORTH...UPR 30S S.
SUN/SUN NIGHT...LOOKS TO BE A COLD DAY ON SUNDAY WITH NE FLOW. ONLY
CONCERN WOULD BE FOR FREEZING DRIZZLE IN THE MORNING OVER CENTRAL
VA...INCLUDING METRO RICHMOND AND AREAS ON NW AS LOW LEVELS REMAIN
BELOW CRITICAL THRESHOLDS FOR FROZEN PRECIP. VERY DRY ALOFT
HOWEVER...SO THIS WOULD BE NOTHING MORE THAN FREEZING DRIZZLE...WILL
MAKE AN HWO MENTION FOR NOW. SHOULD BE WARM ENOUGH FOR JUST -RADZ
BY AFTN (EXCEPT COULD BE CLOSE IN THE COLDER FAR NW ZONES. DOUBT
WE`LL SEE ANY BREAKS IN THE CLOUD COVER AS LOW LEVEL INVERSION
WILL BE DIFFICULT TO MIX OUT...PERHAPS A FEW PEEKS OF SUN IN THE
MORNING OVER THE FAR NORTH CLOSEST TO THE SFC HIGH. BREEZY
CONDITIONS ALONG THE COAST. FAVOR THE COLDER MET NUMBERS FOR
HIGHS...BASED ON LIMITED MIXING AND A LOW OVC...HIGHS RANGING FROM
THE UPPER 40S FAR SE VA/NE NC...MID- UPPER 30S NW ZONES. TEMPS
RISE OVERNIGHT SUNDAY NIGHT...AS SFC HIGH OVER NEW ENGLAND
RETREATS OFF TO THE NE...FOLLOWED BY SIGNIFICANT WARM-UP ON MON
AHEAD OF THE NEXT SYSTEM. FAVOR THE WARMER MAV VALUES ON MON W/
SSW FLOW BY LATE MORNING AFTN...HIGHS GENLY IN THE UPR 50S NW
(WHERE PRECIP COMES IN EARLIER) TO THE MID- UPR 60S SE. CHC TO
LIKELY POPS FOR SHOWERS ALL AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A SERIES OF WAVES WILL PASS NORTH OF THE FA DURING THE LONG TERM
PERIOD DRAGGING COLD FRONTS AND PERIODS PRECIP THROUGH THE AREA.
RAIN WILL BEGIN TO IMPACT THE AREA MONDAY AS AN UPPER LEVEL WAVE
PASSES OVER NORTHERN MICHIGAN. THE ASSOCIATED COLD FRONT CROSSES THE
AREA BRINGING A PERIOD OF RAIN AND A WIND SHIFT FROM THE S TO N. THE
MODELS VARY A BIT WITH THE STRENGTH OF THE SYSTEM...AND HAVE LEANED
TOWARD THE WEAKER ECMWF. BUT...IF THE GFS VERIFIES THERE COULD BE A
COUPLE TSTMS THAT DEVELOP IN NE NC AND SE VA. BENIGN WX PREVAILS AS
HIGH PRESSURE BUILDS OVER THE AREA TUESDAY NIGHT AND SLIDES OFF THE
COAST BY THURSDAY EVENING. THE NEXT SYSTEM LOOKS TO IMPACT THE AREA
FRIDAY MORNING AS A WARM FRONT BRINGS RAIN INTO THE AREA...FOLLOWED
BY A COLD FRONT THAT WILL BRING ANOTHER ROUND OF RAIN LATE FRI/EARLY
SAT. AGAIN THERE IS A BIT OF DISAGREEMENT WITH THE MODEL TIMING OF
THIS EVENT. THE ECMWF PROGRESSES THE UPPER LEVEL SYSTEM EAST MUCH
MORE QUICKLY THAN THE GFS. BEING THIS FAR OUT IN THE FORECAST...JUST
TRIED TO BLEND THE TIMING OF THE SCENARIOS TOGETHER.
EXPECT A BIT OF A ROLLER COASTER AS FAR AS TEMPS GO DURING THE
PERIOD. WITH THE APPROACH THE SYSTEM MONDAY...EXPECT HIGHS IN THE
MID 60S NORTH TO UPPER 60S SOUTH. AS THE FRONT CLEARS THE AREA
MILDER TEMPS WILL PREVAIL WITH HIGHS IN THE MID 50S TO 60 FOR TUES
AND WED. A WARMER DAY FOLLOWS ON THUR AS WINDS TURN SOUTH AHEAD OF
THE NEXT FRONT. LOWS WILL BE IN THE LOW 40S TUES...FALLING TO THE
LOW AND MID 30S FOR WED AND THUR...WARMING INTO THE MID 40S FOR FRI
AND SAT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
ONGOING LIGHT TO MOD PCPN THIS MORNING IN ASSOCIATION WITH WEAK
ISENTROPIC LIFT. MVFR/TEMPO IFR CONDS ACROSS ALL BUT FAR SE
TERMINALS AS OF 06Z/1A...WITH CONDITIONS EXPECTED TO DETERIORATE TO
IFR BY 12Z/SAT AT NORTHERN TERMINALS AND CONTINUE THROUGHOUT THE
DAY. PCPN REMAINS IN FORM OF VERY LIGHT FZRA AT RIC AND HAS BEGUN AS
LGT SNOW AT SBY BUT CHANGE TO RAIN AT ALL TERMINALS IS EXPECTED BY
10Z.
NE/E WINDS FRIDAY EVENING VEER TO THE S/SW LATER THIS MORNING AS A
WARM FRONT LIFTS ACROSS THE AREA, BEFORE TURNING BACK TO THE NORTH
LATE SATURDAY AFTN AS LOW PRESSURE TRACKS TO OUR WEST/NORTHWEST,
PUSHING A COLD FRONT THROUGH THE AREA SAT AFTN/NIGHT.
OUTLOOK: ALTHOUGH PCPN IS EXPECTED TO END SAT NIGHT...WIDESPREAD IFR
IS FCST TO CONTINUE THROUGH SUNDAY AND PROBABLY MONDAY. A CHANCE FOR
RAIN RETURNS WITH THE NEXT COLD FRONT PASSAGE ON MONDAY WITH
IMPROVING CONDITIONS BEHIND THE FRONTAL PASSAGE FOR TUESDAY THROUGH
MIDWEEK.
&&
.MARINE...
LATEST WX ANALYSIS/OBSERVATIONS SHOWS WARM FRONT DRAPED JUST SOUTH
OF THE WATERS THIS MORNING...RESULTING IN E-SE WINDS AS OF 09Z.
WINDS WILL CONTINUE TO VEER TOWARDS THE S-SW THIS MORNING AS WARM
FRONT PUSHES NORTH (WHILE INCREASING IN SPEED (TO AVG 15-20 KT))
THROUGH MIDDAY. WARM FRONT WILL MEANDER JUST NORTH OF THE WATERS
LATE THIS MORNING INTO THE AFTN...BEFORE BEING SHUNTED BACK S ACROSS
THE WATERS THIS AFTN INTO TONIGHT AS SFC LO PRES MOVING ACROSS NC
PUSHES OFFSHORE. RESULTANT WIND DIRECTION WILL VEER AROUND TO THE
N-NE BEHIND THE FRONTAL PASSAGE. PRESSURE GRADIENT WILL TIGHTEN
SIGNIFICANTLY AS SFC HIGH PRESSURE CURRENTLY OVER THE UPPER MIDWEST
SLIDES ACROSS NORTHEAST US. THIS WILL RESULT IN WINDS RAMPING
UPWARDS INTO SCA CRIT RANGE (20 TO 25 KT)...WITH HIGHEST WINDS
EXPECTED AFTER 00Z/7PM TONIGHT THROUGH SUN MRNG. WINDS BEGIN TO
DIMINISH AS GRADIENT SLACKENS SUN AFTN...THOUGH RMN FM THE NE.
ONLY MINOR CHANGE TO SCA WAS TO RUN THROUGH SUN AFTN OVER THE BAY,
AND THROUGH LATE SUNDAY NIGHT OVER THE COASTAL WATERS.
WINDS BECOME LIGHT SUNDAY NIGHT INTO EARLY MONDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVERHEAD, BUT RAMP UPWARDS GRADUALLY MONDAY AFTN
AHEAD OF THE NEXT FRONTAL SYSTEM WHICH APPROACHES FROM THE W MONDAY.
WINDS WL INITIALLY BE HIGHER OVER LAND MONDAY AFTN, BUT EVENTUALLY
EXPECT ANOTHER ROUND OF SCA CONDITIONS BY MONDAY NIGHT. CONDITIONS
IMPROVE BACK BELOW SCA CRITERIA ON TUE AS HIGH RPESSURE REBUILDS
INTO THE REGION FROM THE WEST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
VAZ048-049-062>064.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 3 PM EST SUNDAY
FOR ANZ634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 3 PM EST SUNDAY FOR
ANZ630>633.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...LKB
LONG TERM...DAP
AVIATION...MAM
MARINE...MAM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1038 AM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTICELLULAR STORM TYPE...AND ML LAPSE RATES IMPROVE
ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES. 0-3 KM
SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY INCREASING
UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN AREAS WITH
LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE REFLECTIVITY AS A
GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE EARLY AFTN...WITH
PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN 3P-4P...AND EXITING
OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF GUSTY WINDS FROM WX
GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT. OF COURSE...CANNOT
RULE OUT AN ISOLATED DAMAGING WIND GUST...ESPECIALLY WITHIN ANY
BOWING SEGMENTS/STRUCTURES WITHIN THE LINE...BUT PRIMARY THREATS
WILL BE SUB-SEVERE WIND AND SMALL HAIL. WILL OF COURSE MONITOR...IF
MORE SUNSHINE BREAKS OUT THAN ANTICIPATED...THIS COULD ENHANCE THE
SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...LIGHT RAIN NEAR LBT TO ILM WILL COME TO AN END SHORTLY
AFTER 12Z LEAVING ALL TERMINALS UNDER VFR CONDITIONS. BROKEN TO
OVERCAST CLOUD VFR CLOUD COVER WILL PERSIST THROUGH MUCH OF THE DAY.
SOUTH-SOUTHWEST TO SOUTHWEST WINDS WINDS WITH GUSTS TO 25-28 KNOTS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. FORECAST WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DEVELOPS IT WILL REMAIN EAST OF
THE CRE/MYR TERMINALS.
A LINE OF CONVECTIVE SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS
WILL PRECEDE THE COLD FRONT AND AFFECT THE FLO/LBT TERMINALS 20-22Z
AND THE COASTAL TERMINALS BY 00-02Z. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS. TEMPO MVFR LIKELY WITH THE
SHOWERS...WITH ANY IFR TOO SHORT LIVED TO MENTION IN TAFS ATTM.
SHOWERS/MVFR CONDITIONS BECOME LIKELY AS THE COLD FRONT APPROACHES
THIS EVENING. POST FRONTAL IFR CEILINGS AND VISIBILITIES IN LIGHT
RAIN AND DRIZZLE LIKELY MID TO LATE EVENING...EXCEPT SHORTLY AFTER
MIDNIGHT AT MYR/CRE.
EXTENDED OUTLOOK...POTENTIAL MVFR CIGS/ISOLATED IFR CIGS SUNDAY.
ANTICIPATE VFR MONDAY THROUGH EXTENDED PERIOD WITH EXCEPTION OF
POSSIBLE MVFR EARLY MONDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 5 PM EST
THIS AFTERNOON FOR AMZ254-256.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR AMZ250-252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
940 AM CST SAT JAN 21 2012
.DISCUSSION...FORECAST CHALLENGE CONCERNS WIND AND TEMPERATURES.
WARM ADVECTION AND STIFF SE WINDS TO CONTINUE TODAY. RUC SOUNDINGS
INDICATING 30-40KTS AT 925MB HOWEVER MIXED LAYER VERY SHALLOW SO NOT
CONFIDENT STRONGER WINDS WILL MIX DOWN. WILL BE WINDY BUT FEELING
NOW IS WINDS WILL STAY BLO ADVISORY CRITERIA. OTHERWISE CANADIAN
RADARS INDICATING -SN BREAKING OUT ACROSS SOUTHERN PRAIRIE PROVINCES
ON LEADING EDGE OF WARM ADVECTION. MOST LOOKS WELL NORTH OF BORDER
BUT WILL NOT HURT TO MAINTAIN SLIVER OF LOW POPS ALONG BORDER.
TEMPERATURES CLIMBING A LITTLE AHEAD OF SCHEDULE BUT WITH MORE
CLOUDS THAN SUN TODAY FEEL MAXIMUM VALUES IN LINE. WILL MAKE SOME
MINOR ADJUSTMENTS BUT OVERALL CURRENT FORECAST LOOKS GOOD.
&&
.AVIATION...
VFR CEILINGS WILL PERSIST THROUGH AT LEAST 21 UTC...AND THEN
SLOWLY BEGIN TO FALL LATE THIS AFTERNOON AND EVENING AS A LOW
PRESSURE SYSTEM MOVES INTO THE REGION. A SNOW/SLEET/FREEZING RAIN MIX
IS POSSIBLE FOR AIRFIELDS ALONG AND WEST OF THE VALLEY AFTER 00
UTC...BUT ALL PRECIPITATION SHOULD CHANGE OVER TO SNOW AROUND
SUNRISE. EXACT PRECIPITATION TIMING...PHASE AND COVERAGE IS STILL
UNCERTAIN...SO MULTIPLE TAF UPDATES ARE POSSIBLE OVER THE NEXT 24
HOURS. STRONG SOUTHERLY WIND WILL DEVELOP THIS MORNING WITH
AFTERNOON GUSTS UP TO 30 KTS. PATCH OF MVFR CIGS ACROSS EASTERN SD
AND WILL NEED TO MONITOR NORTHWARD MOVEMENT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
725 AM CST SAT JAN 21 2012
.UPDATE...
MINOR UPDATE THIS MORNING TO INCREASE CLOUD COVER FOR TODAY. LOW
STRATUS DECK ADVECTING NORTHWARD ALONG THE I-29 CORRIDOR QUITE
RAPIDLY THIS MORNING. 06Z RUC ALSO EXPANDS THIS AREA OF CLOUDS
NORTHWESTWARD DURING THE MORNING HOURS.
UPDATED 12Z AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...THROUGH MONDAY
WINTER CONTINUES. WITH WIDESPREAD TEMPERATURES AROUND/BELOW ZERO
THIS AM...WARM ADVECTION ALOFT WILL RESULT IN A STRONG INVERSION
JUST OFF THE SURFACE. THIS...ALONG WITH A LESS THAN FAVORABLE
MIXING DIRECTION WILL TRANSLATE THE 50KT LOW LEVEL JET OVER THE
EASTERN CWA INTO MERELY BREEZY CONDITIONS AT THE SURFACE. GIVEN
THE LIGHT POWDER...SHOULD SEE SOME BLOWING SNOW THOUGH IT IS
UNLIKELY TO RESULT IN WIDESPREAD REDUCTIONS TO VISIBILITY. WARM
ADVECTION AHEAD OF A CLIPPER SYSTEM WILL ONLY MAKE CONDITIONS MORE
HAZARDOUS AS ANY LIGHT PRECIPITATION WITHIN THE SYSTEMS WARM
SECTOR WILL RESULT IN SLEET OR FREEZING RAIN. EVEN WHERE
TEMPERATURES WARM ABOVE ZERO TODAY...THE GROUND SHOULD REMAIN VERY
COLD AND RESULT IN SOME ICING CONDITIONS. AS THE SYSTEM SLOWLY
PROGRESSES EAST...BUFKIT PROFILES INITIALLY SHOWING INTERMITTENT
LIFT/SATURATION IN THE DENDRITIC GROWTH ZONE WITH DRY/MILD LOW
LEVEL AIR MAKING PTYPE DIFFICULT TO INTERPRET TRANSITIONS TO
PROFILES CONDUCIVE FOR ALL SNOW. THE COLD ADVECTION RESPONSIBLE
FOR THIS CHANGE OVER WILL ALSO LEAD TO STRONG WINDS WITH H85 WINDS
TOPPING 60KTS...RESULT IN IN CONTINUED WINTER WEATHER IMPACTS.
GOOD MIXING INITIALLY MEANS HIGHS SUNDAY ABOVE FREEZING...WITH
TEMPERATURES FALLING THROUGH THE REST OF THE DAY.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
FORECAST PERIOD BEGINS WITH AN ELONGATED NORTH TO SOUTH SURFACE
HIGH PRESSURE OVER THE CWA MONDAY NIGHT. THIS SFC HIGH IS PROGGED
TO GRADUALLY SLIDE SEWD ON TUESDAY. GLOBAL MODELS THEN DROP A WEAK
CLIPPER SHORT- WAVE TROUGH SEWD THROUGH ERN ND WEDNESDAY. ANOTHER
CLIPPER WAVE IS THEN FORECAST TO MOVE EWD THROUGH CENTRAL ND
THURSDAY. LATEST MODEL RUNS ARE DRY WITH BOTH OF THE UPPER TROUGH
AND ASSOCIATED WEAK COLD FRONTAL PASSAGES...KEEPING SNOW CHANCES
IN NORTH DAKOTA. ALL IN ALL A DRY WEEK APPEARS IN STORE FOR THE
CWA WITH TEMPERATURES ABOUT 10 DEGREES ABOVE SEASONAL AVERAGES FOR
LATE JANUARY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN AREA OF MVFR CIGS WILL CONTINUE TO MOVE NORTH ALONG THE I-29
CORRIDOR THIS MORNING...IMPACTING KATY. THE CIGS WILL ALSO EXPAND
NORTHWESTWARD DURING THE MORNING HOURS. SOUTH WINDS WILL BE ON THE
INCREASE AROUND MID-MORNING WITH WINDS GUSTING TO ABOUT 30 KTS AT
ALL TAF SITES. LOW LEVEL WIND SHEAR IS EXPECTED AT KABR AND KATY
FROM APPROXIMATELY MID MORNING THROUGH THE AFTERNOON. THE STRONG
SOUTH WINDS WILL SUBSIDE DURING THE EVENING. AS AN UPPER LEVEL
TROUGH AND SFC COLD FRONT APPROACH THE REGION TONIGHT...A MIXED BAG OF
PRECIPITATION IS EXPECTED OVERNIGHT WITH -FZDZ/-PL/-SN ALONG WITH
WDSPRD IFR/LIFR CIGS AND MVFR VSBYS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ SUNDAY NIGHT FOR BROWN-CAMPBELL-
CORSON-DEWEY-EDMUNDS-FAULK-MCPHERSON-POTTER-WALWORTH.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR CLARK-CODINGTON-DAY-DEUEL-GRANT-HAMLIN-
MARSHALL-ROBERTS-SPINK.
MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR BIG STONE-TRAVERSE.
&&
$$
UPDATE...CHURCH
SHORT TERM...CONNELLY
LONG TERM...CHURCH
AVIATION...CHURCH
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
521 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 300 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AREA OF MVFR CIGS ACROSS SOUTHEAST SOUTH DAKOTA WILL MOVE ENE THIS
MORNING AS SW WINDS DEVELOP ABOVE THE SURFACE. BASED UPON CURRENT
MOVEMENT...LOW CLOUDS SHOULD MOVE EAST OF KHON AND KFSD BY 14Z AND
KSUX BY 15Z. OTHERWISE...WINDS EXPECTED TO REALLY INCREASE THIS
MORNING WITH WINDS GUSTING OVER 30 KTS EXPECTED IN MOST AREAS BY
EARLY THIS AFTERNOON. WITH FRESH SNOW COVER EXPECT SOME BLOWING SNOW
BUT THE BOUNDARY LAYER IS RELATIVELY STABLE WITH THE WARM AIR
ADVECTION DEVELOPING SO THAT REALLY SHOULD LIMIT THE REDUCED
VISIBILITIES TO ONLY A COUPLE OF HOURS THIS AFTERNOON WHEN WINDS
ARE MOST LIKELY TO GUST OVER 30 KTS. WINDS WILL DECREASE A LITTLE
TONIGHT AND THE MID AND UPPER CLOUDS WILL MOVE OVER. WITH A STRONG
PV ANOMALY MOVING OVER THE 850 MB BOUNDARY IN CENTRAL SD LATE
TONIGHT...DID BRING MVFR CIGS BACK INTO HURON LATE TONIGHT. THERE IS
A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 09Z BUT THE PROBABILITY
IS LOW ENOUGH THAT DID NOT INCLUDE IN TAF AT THIS TIME.
HOWEVER...SNOW...POSSIBLY MIXED WITH FREEZING RAIN...ARE MORE LIKELY
LATE SUNDAY MORNING AND SUNDAY AFTERNOON ACROSS MOST OF SE SD AND
WILL LIKELY IMPACT CIGS AND VSBYS./SCHUMACHER
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
225 PM EST SAT JAN 21 2012
.SYNOPSIS...
A HIGH PRESSURE SYSTEM WILL BUILD INTO THE NORTHEAST TONIGHT AND
SUNDAY...BRINGING FAIR BUT COLD WEATHER. ON MONDAY...A POWERFUL
STORM WILL MOVE FROM THE UPPER GREAT LAKES REGION INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM...SNOW HAS ENDED OR BECOME VERY LIGHT ACROSS THE
ADVISORY AREA (ULSTER...DUTCHESS...LITCHFIELD COUNTIES)...SO
CANCELLED THE ADVISORY JUST AFTER 200 PM. ONLY DECREASING CHANCE
POPS FORECAST FOR THE REST OF THE AFTERNOON. TEMPS HAVE ALSO BEEN
ADJUSTED DOWNWARD SINCE IT APPEARS THAT ANY CLEARING THAT OCCURS
WILL LIKELY ARRIVE TO LATE FOR THE SUN TO HAVE ANY IMPACT ON TEMPS.
****PREVIOUS DISCUSSION****
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SNOW WAS PRETTY MUCH ENDED AT KALB. KGFL WAS EXPERIENCING A PLUME
OF LIKELY WIND CONVERGENCE -SN/-SHSN EMANATING FROM THE TUG HILL
AREA. HAVE GONE WITH JUST A ONE-HOUR TAF ONSET TEMPO GROUP THERE
FOR IFR VSBY IN -SN AS THIS FEATURE WILL WEAKEN AS A HIGH PRESSURE
RIDGE BUILDS IN THROUGH THIS EVENING. OTRW...BOTH KGFL AND KALB
WILL HANG ONTO MVFR CLOUDS FOR AWHILE. AT KPOU...TIMING OF ACTIVITY
PULLOUT IS SOMEWHAT UNCERTAIN. HAVE IT ENDING AT 22Z. LIKE KGFL...
HAVE GIVEN THEM A ONE-HOUR ONSET TEMPO OF IFR VSBY IN -SN TO REFLECT
MOST RECENT SCENARIO...BUT UNLIKE KGFL...A DIFFERENT MECHANISM.
SUBSIDENCE HIGH PRESSURE ENHANCES OVER THE AIRPORTS THIS EVENING.
DEPARTING LOW IS NOT EXPECTED TO STRENGTHEN AS THIS OCCURS...SO
GRADUAL CLEARING OF ALL THE LOW AND MID LEVEL CLOUDS IS EXPECTED
THROUGH THE NIGHT WHILE WINDS DIMINISH. HIGH CLOUDINESS IS EXPECTED
TO MOVE IN WELL AHEAD OF THE NEXT SYSTEM...BUT SHOULD REMAIN THIN.
GIVEN THIS SCENARIO...WINDS WILL NOT BE OF GREAT CONCERN...WITH
NEARLY CALM SURFACE CONDITIONS EXPECTED ON SUNDAY. SOME LOW- TO
MID-LEVEL WIND ENHANCEMENT WILL OCCUR...BUT THIS WILL FALL WELL
SHORT OF PRODUCING ANY WIND SHEAR ISSUES. TEMPERATURES OF GROUND
AND DRY AIR REMAINING QUITE COLD OVERNIGHT WILL KEEP FOG CLEAN OUT
OF THE PICTURE.
OUTLOOK...
SUN PM...VFR...NO SIG WX.
MON AM...MAINLY VFR...CHC -FZDZ.
MON AFTN-EVENING...MVFR/IFR RA LIKELY
MON NGT-WED...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/SNYDER/SND
NEAR TERM...GJM/SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1252 PM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SNOW WAS PRETTY MUCH ENDED AT KALB. KGFL WAS EXPERIENCING A PLUME
OF LIKELY WIND CONVERGENCE -SN/-SHSN EMANATING FROM THE TUG HILL
AREA. HAVE GONE WITH JUST A ONE-HOUR TAF ONSET TEMPO GROUP THERE
FOR IFR VSBY IN -SN AS THIS FEATURE WILL WEAKEN AS A HIGH PRESSURE
RIDGE BUILDS IN THROUGH THIS EVENING. OTRW...BOTH KGFL AND KALB
WILL HANG ONTO MVFR CLOUDS FOR AWHILE. AT KPOU...TIMING OF ACTIVITY
PULLOUT IS SOMEWHAT UNCERTAIN. HAVE IT ENDING AT 22Z. LIKE KGFL...
HAVE GIVEN THEM A ONE-HOUR ONSET TEMPO OF IFR VSBY IN -SN TO REFLECT
MOST RECENT SCENARIO...BUT UNLIKE KGFL...A DIFFERENT MECHANISM.
SUBSIDENCE HIGH PRESSURE ENHANCES OVER THE AIRPORTS THIS EVENING.
DEPARTING LOW IS NOT EXPECTED TO STRENGTHEN AS THIS OCCURS...SO
GRADUAL CLEARING OF ALL THE LOW AND MID LEVEL CLOUDS IS EXPECTED
THROUGH THE NIGHT WHILE WINDS DIMINISH. HIGH CLOUDINESS IS EXPECTED
TO MOVE IN WELL AHEAD OF THE NEXT SYSTEM...BUT SHOULD REMAIN THIN.
GIVEN THIS SCENARIO...WINDS WILL NOT BE OF GREAT CONCERN...WITH
NEARLY CALM SURFACE CONDITIONS EXPECTED ON SUNDAY. SOME LOW- TO
MID-LEVEL WIND ENHANCEMENT WILL OCCUR...BUT THIS WILL FALL WELL
SHORT OF PRODUCING ANY WIND SHEAR ISSUES. TEMPERATURES OF GROUND
AND DRY AIR REMAINING QUITE COLD OVERNIGHT WILL KEEP FOG CLEAN OUT
OF THE PICTURE.
OUTLOOK...
SUN PM...VFR...NO SIG WX.
MON AM...MAINLY VFR...CHC -FZDZ.
MON AFTN-EVENING...MVFR/IFR RA LIKELY
MON NGT-WED...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1213 PM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS/VSBY IN -SN EXIST OVER MOST OF FCA. OVER NEXT FEW HRS MOST
AREAS FM ADIRONDACKS SOUTH WILL LOWER TO MVFR/IFR CIGS AND VSBY IN
-SN. IFR CONDS WILL BE MORE WIDESPREAD SOUTH. CONDS WILL IMPV DURING
THE AFTN BCMG MVFR FM NW TO SE...AND VFR BY EVENING. WINDS WILL BE
NORTH-NORTHEAST AROUND 5-10 KT TODAY.
OUTLOOK...
SAT NIGHT-SUN...VFR. NO SIG WX.
SUN NIGHT-MON MRNG...BCMG MVFR/IFR LATE. CHC -RA/-SN/-PL/-FZRA.
MON AFTN...MVFR/IFR. RA LIKELY.
MON NIGHT-TUE...VFR. SLIGHT CHC -SHRASN AND MVFR.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...SNYDER
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
226 PM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 800 PM...WIDESPREAD SHOWERS WERE OCCURRING AHEAD OF THE
COLD FRONT. THE SOUTH LOW-LEVEL FLOW PLUS A MOISTURE AND
INSTABILITY INCREASE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH WILL SUPPORT A FEW THUNDERSTORMS. THE EARLY AFTERNOON 88D
VAD WIND PROFILE INDICATED WINDS OF 45 KNOTS AT 3000 FEET. THE
LATEST RUC SHOWS THE SHEAR CONTINUING THROUGH THE REST OF THE
AFTERNOON. ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE
THUNDERSTORMS. THE EARLY AFTERNOON ANALYSIS SHOWED LI/S RANGING
FROM 4 IN THE NORTH TO AROUND ZERO IN THE SOUTH APART OF THE
FORECAST AREA. UPSTREAM INSTABILITY SUPPORT THE NAM/S FORECAST OF
LI/S LOWERING TO AROUND -2 OVER THE SOUTH PART. SEVERE
THUNDERSTORMS APPEARS POSSIBLE IN THE SOUTH PART BASED ON THIS
INSTABILITY AND SHEAR.
AFTER 800 PM...
THE COLD FRONT WILL SINK SOUTH OF THE FORECAST AREA TONIGHT. THE GFS
AND NAM SHOW THE H85 JET LIFTING NORTHEAST OF THE FORECAST AREA
EARLY WITH MOISTURE BECOMING SHALLOW BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. THE GFS AND NAM MOS INDICATE LOW POPS. FORECASTED CHANCE
POPS MAINLY ASSOCIATED WITH LINGERING CONVERGENCE NEAR THE FRONT.
USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE NAM AND GFS KEEP THE FRONT SOUTH OF THE AREA SUNDAY. THE MODELS
KEEP MOISTURE SHALLOW BUT SHOULD ISENTROPIC LIFT DEVELOPING. THIS
LIFT MAY SUPPORT LIGHT RAIN OR DRIZZLE. THE TEMPERATURE GUIDANCE
APPEARS TOO WARM BECAUSE OF THE WEDGE PATTERN. EXPECT THE WEDGE
PATTERN WILL REMAIN IN PLACE FOR MUCH OF SUNDAY NIGHT. THE MODELS
SHOW ANOTHER COLD FRONT MONDAY WITH INCREASED MOISTURE AND
CONVERGENCE. THE DEEPER MOISTURE APPEARS TO OCCUR DURING THE
MORNING. THE WARMER TEMPERATURE GUIDANCE APPEARED BETTER SUNDAY
NIGHT BECAUSE OF CLOUDINESS AND MIXING ASSOCIATED WITH THE
APPROACHING FRONT. THE TEMPERATURE GUIDANCE WAS CLOSE MONDAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
DRY RIDGING BEHIND THE COLD FRONT SHOULD DOMINATE TUESDAY. THE GFS
AND ECMWF SUPPORT THIS DRY PATTERN. THE GFS AND ECMWF HAVE BEEN
INCONSISTENT WITH THE TIMING AND MOISTURE DURING THE REST OF THE
EXTENDED PERIOD. THE ECMWF HAS BEEN GENERALLY FASTER MOVING A WARM
ADVECTION AND HIGH MOISTURE BACK INTO THE FORECAST AREA. THE GFS
ENSEMBLE MEANS SUPPORT POPS LESS THAN 20 PERCENT WEDNESDAY...AND
CHANCE POPS DURING THE REST OF THE EXTENDED PERIOD.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD SHOWERS WILL CONTINUE AHEAD OF THE COLD FRONT. THERE
WILL ALSO BE A FEW THUNDERSTORMS...BUT THESE WERE NOT INCLUDED IN
THE FORECAST EXPLICITLY BECAUSE OF TIMING UNCERTAINTY. STRONG
WINDS ALOFT MAY MIX DOWN TO THE SURFACE WITH SOME OF THE STRONGER
SHOWERS. GENERALLY EXPECT MVFR CONDITIONS IN THE WARM SECTOR AHEAD
OF THE FRONT WITH LOWER CONDITIONS AT TIMES IN HEAVIER SHOWERS.
THE COLD FRONT WILL SINK SOUTH OF THE AREA IN THE 04Z TO 08Z TIME
FRAME. IFR CEILINGS WILL OCCUR IN THE MOIST NORTH FLOW BEHIND THE
FRONT.
EXTENDED AVIATION OUTLOOK...WIDESPREAD IFR CEILINGS WILL LIKELY
OCCUR DURING THE REST OF SUNDAY AND SUNDAY NIGHT ASSOCIATED WITH A
WARM FRONT. A COLD FRONT BE BE IN THE AREA MONDAY WITH CONTINUED
RESTRICTIONS FOR MUCH OF MONDAY. WIDESPREAD IFR CONDITION MAY
OCCUR WEDNESDAY NIGHT THROUGH THURSDAY ASSOCIATED WITH ANOTHER
FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
105 PM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 800 PM...WIDESPREAD SHOWERS WERE OCCURRING AHEAD OF THE
COLD FRONT. THE SOUTH LOW-LEVEL FLOW PLUS A MOISTURE AND
INSTABILITY INCREASE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH WILL SUPPORT THUNDERSTORMS. THE EARLY AFTERNOON 88D VD
WIND PROFILE INDICATED WINDS OF 45 KNOTS AT 3000 FEET. THE LATEST
RUC SHOWS THE SHEAR CONTINUING THROUGH THE REST OF THE AFTERNOON.
ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE THUNDERSTORMS. THE EARLY
AFTERNOON ANALYSIS SHOWED LI/S RANGING FROM 4 IN THE NORTH TO
AROUND ZERO IN THE SOUTH APART OF THE FORECAST AREA. UPSTREAM
INSTABILITY SUPPORT THE NAM/S FORECAST OF LI/S LOWERING TO AROUND
-2 OVER MUCH OF THE AREA DURING THE AFTERNOON. THE THREAT OF
SEVERE WEATHER APPEARS TO BE UNTIL AROUND 800 PM BASED ON THE
LATEST RUC MOISTURE CONVERGENCE PATTERN AND H85 JET.
AFTER 800 PM...
THE COLD FRONT WILL SINK SOUTH OF THE FORECAST AREA TONIGHT. THE GFS
AND NAM SHOW THE H85 JET LIFTING NORTHEAST OF THE FORECAST AREA
EARLY WITH MOISTURE BECOMING SHALLOW BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. THE GFS AND NAM MOS INDICATE LOW POPS. FORECASTED CHANCE
POPS MAINLY ASSOCIATED WITH LINGERING CONVERGENCE NEAR THE FRONT.
USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
THE NAM AND GFS KEEP THE FRONT SOUTH OF THE AREA SUNDAY. THE MODELS
KEEP MOISTURE SHALLOW BUT SHOULD ISENTROPIC LIFT DEVELOPING. THIS
LIFT MAY SUPPORT LIGHT RAIN OR DRIZZLE. THE TEMPERATURE GUIDANCE
APPEARS TOO WARM BECAUSE OF THE WEDGE PATTERN. EXPECT THE WEDGE
PATTERN WILL REMAIN IN PLACE FOR MUCH OF SUNDAY NIGHT. THE MODELS
SHOW ANOTHER COLD FRONT MONDAY WITH INCREASED MOISTURE AND
CONVERGENCE. THE DEEPER MOISTURE APPEARS TO OCCUR DURING THE
MORNING. THE WARMER TEMPERATURE GUIDANCE APPEARED BETTER SUNDAY
NIGHT BECAUSE OF CLOUDINESS AND MIXING ASSOCIATED WITH THE
APPROACHING FRONT. THE TEMPERATURE GUIDANCE WAS CLOSE MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DRY RIDGING BEHIND THE COLD FRONT SHOULD DOMINATE TUESDAY. THE GFS
AND ECMWF SUPPORT THIS DRY PATTERN. THE GFS AND ECMWF HAVE BEEN
INCONSISTENT WITH THE TIMING AND MOISTURE DURING THE REST OF THE
EXTENDED PERIOD. THE ECMWF HAS BEEN GENERALLY FASTER MOVING A WARM
ADVECTION AND HIGH MOISTURE BACK INTO THE FORECAST AREA. THE GFS
ENSEMBLE MEANS SUPPORT POPS LESS THAN 20 PERCENT WEDNESDAY...AND
CHANCE POPS DURING THE REST OF THE EXTENDED PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD SHOWERS WILL CONTINUE AHEAD OF THE COLD FRONT. THERE
WILL ALSO BE A FEW THUNDERSTORMS...BUT THESE WERE NOT INCLUDED IN
THE FORECAST EXPLICITLY BECAUSE OF TIMING UNCERTAINTY. STRONG
WINDS ALOFT MAY MIX DOWN TO THE SURFACE WITH SOME OF THE STRONGER
SHOWERS. GENERALLY EXPECT MVFR CONDITIONS IN THE WARM SECTOR AHEAD
OF THE FRONT WITH LOWER CONDITIONS AT TIMES IN HEAVIER SHOWERS.
THE COLD FRONT WILL SINK SOUTH OF THE AREA IN THE 04Z TO 08Z TIME
FRAME. IFR CEILINGS WILL OCCUR IN THE MOIST NORTH FLOW BEHIND THE
FRONT.
EXTENDED AVIATION OUTLOOK...WIDESPREAD IFR CEILINGS WILL LIKELY
OCCUR DURING THE REST OF SUNDAY AND SUNDAY NIGHT ASSOCIATED WITH A
WARM FRONT. A COLD FRONT BE BE IN THE AREA MONDAY WITH CONTINUED
RESTRICTIONS FOR MUCH OF MONDAY. WIDESPREAD IFR CONDITION MAY
OCCUR WEDNESDAY NIGHT THROUGH THURSDAY ASSOCIATED WITH ANOTHER
FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1011 AM CST SAT JAN 21 2012
.DISCUSSION...
ISSUED 1011 AM CST SAT JAN 21 2012
DESPITE RIDGE OF HIGH PRESSURE EXTENDING FROM THE NORTHERN GREAT
LAKES INTO THE PLAINS...LOW CLOUDS CONTINUE TO BLANKET NEARLY ALL
OF CENTRAL ILLINOIS THIS MORNING. THE EXCEPTION IS ACROSS THE FAR
NORTHEAST KILX CWA AROUND KCMI AND KDNV...WHERE AN INTRUSION OF DRY
AIR FROM THE NORTHEAST HAS RESULTED IN A LARGE BREAK IN THE
OVERCAST. LOW-LEVEL PROFILERS ARE CURRENTLY SHOWING NORTHEASTERLY
WINDS...HOWEVER THESE WILL VEER MORE EASTERLY THIS AFTERNOON AS
THE HIGH PRESSURE CENTER SHIFTS INTO MICHIGAN. THIS SHOULD PUSH
THE CLEARING SLOWLY WESTWARD AS THE DAY PROGRESSES...WITH MOSTLY
SUNNY SKIES EXPECTED IN THE BLOOMINGTON-NORMAL AND SPRINGFIELD
AREAS BY EARLY AFTERNOON. MEANWHILE...SKIES WILL REMAIN MOSTLY
CLOUDY ALONG AND WEST OF THE ILLINOIS RIVER AND ALONG/SOUTH OF
I-70. DUE TO A NORTHEASTERLY FETCH OFF LAKE MICHIGAN...THE
NORTHWEST KILX CWA MAY EVEN SEE A FEW SNOW FLURRIES FROM TIME TO
TIME. ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 556 AM CST SAT JAN 21 2012...FOR THE 12Z TAFS
IFR STRATUS WILL CONTINUE THROUGH MID MORNING...WHEN THE CLOUD
LAYER SHOULD LIFT TO MVFR. PIREPS ARE SHOWING THE CLOUD LAYER AS
ABOUT 2K FT THICK...SO SOME CLEARING MAY DEVELOP AS MIXING DEEPENS
INTO THE DRY LAYER ABOVE 3K FT. THE NORTHWEST EDGE OF THE STRATUS
IS NOT PROGRESSING TO THE ESE AS YOU MIGHT EXPECT BEHIND A LOW
PRESSURE SYSTEM. SO CLEARING IS A TOUGH CALL. RUC AND HRRR MODELS
ARE SHOWING SOME DRYING WORKING INTO OUR AREA FROM THE
NORTHEAST...AS SURFACE WINDS INCREASE FROM THE NORTHEAST. SO CMI
AND DEC MAY BE THE EARLY TERMINAL SITES TO CLEAR OUT TO VFR THIS
AFTERNOON. PIA/BMI/SPI MAY BE DELAYED BY A FEW HOURS TO 20-21Z.
NOT HIGHLY CONFIDENT ON THE CLEARING SCENARIO...BUT WILL INCLUDE
SOME VFR FROM LATE AFTERNOON THROUGH MID EVENING...WHEN MVFR
CLOUDS RETURN ON SOUTHEAST WINDS.
WILL KEEP WINDS IN THE 9-13KT RANGE FOR MOST OF THE NEXT 24
HOURS. SOUTHEAST WIND SPEEDS WILL INCREASE TONIGHT AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE NEXT WEATHER SYSTEM.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 330 AM CST SAT JAN 21 2012
WILL ALLOW THE WINTER WEATHER ADVISORY EXPIRE BY 4 AM SE OF LINCOLN.
MIXED PRECIPITATION HAS PASSED SE OF IL WITH 1008 MB LOW PRESSURE
OVER EASTERN KY. FORECAST CONCERN IS IF ANY CLEARING OCCURS THIS
AFTERNOON. THEN LOOKING AS A FAIRLY STRONG WX SYSTEM TO IMPACT THE
REGION SUNDAY NIGHT WITH SPC HAVE SLIGHT RISK NEAR SOUTHERN PARTS
OF RICHLAND AND LAWRENCE COUNTIES. NCEP FAVORED THE 00Z GFS MODEL
WITH THIS WEATHER SYSTEM WITH ABOVE AVERAGE CONFIDENCE AND WILL
FOLLOW SUITE. LEANED TOWARD THE 00Z ECMWF MODEL WITH MID/LATE WEEK
SYSTEM NEXT WEEK WITH SPLIT UPPER LEVEL FLOW PREVAILING THEN.
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
TRENDED CLOUDIER AND COOLER TODAY WITH FORECAST DUE TO EXTENSIVE
LOW CLOUD COVER ACROSS IL...MO INTO SE HALF OF IA AND LOW LEVEL
MOISTURE TRAPPED IN AN INVERSION. COULD BE A FEW PATCHES OF LIGHT
FREEZING DRIZZLE INTO MID MORNING OVER CENTRAL IL THOUGH HAVE NOT
SCENE ANY REPORTED NEARBY PAST FEW HOURS. TEMPS CURRENTLY RANGE
FROM THE MID TEENS FROM PEORIA NW TO THE MID 20S SE OF I-70. NORTH
WINDS 8 TO 16 MPH. 1027 MB HIGH PRESSURE OVER THE UPPER MS VALLEY
NEAR THE WI/IA/MN BORDER TO DRIFT EAST ACROSS LOWER MI THIS
AFTERNOON AND RIDGING INTO IL. THIS TO DECREASE LOW CLOUDS
OVER NORTHERN AREAS WHERE SKIES BECOME PARTLY SUNNY...WHILE SE IL
STAYS IN THE LOW CLOUDS TODAY. HIGHS MOSTLY IN THE 20S TODAY OVER
CENTRAL IL AND LOWER 30S IN SE IL.
SOUTHERLY FLOW TO SET UP TONIGHT AS HIGH PRESSURE STRENGTHENS TO
1033 MB AS IT MOVES INTO NEW ENGLAND AND MID ATLANTIC STATES BY
DAWN SUNDAY. LOWS PROBABLY REACHED THIS EVENING THEN MAY SNEAK UP
A FEW DEGREES OVERNIGHT AS LOW CLOUDS SPREAD BACK TO THE NORTH. A
FAIRLY STRONG STORM SYSTEM MOVING EAST INTO THE ROCKIES WILL HAVE
A DEEPENING STRONG LOW PRESSURE MOVING INTO THE UPPER MIDWEST
SUNDAY NIGHT AND SWEEP A COLD FRONT EAST THROUGH IL SUNDAY EVENING.
MILDER HIGHS IN THE 40S SUNDAY WITH LOWER 50S IN SE IL. HAVE
SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON...EXCEPT 30% CHANCE NW
OF THE IL RIVER. LIKELY CHANCES OF SHOWERS SUNDAY NIGHT AND EVEN
THUNDERSTORMS FROM I-55 EAST SUNDAY EVENING. WILL NEED TO WATCH SE
IL WITH SLIGHT RISK INTO SOUTHERN PARTS OF RICHLAND AND LAWRENCE
COUNTIES SUNDAY EVENING. VERY STRONG UPPER LEVEL DYNAMICS AND WIND
FIELDS AND DEEP MOISTURE WITH STORM. TEMPS COULD RISE A BIT AHEAD
OF THE COLD FRONT SUNDAY EVENING THEN FALL OVERNIGHT INTO MON
MORNING. MODELS HAVE TRENDED FURTHER NE WITH LIGHT MIXED
PRECIPITATION MONDAY WITH 1025 MB HIGH PRESSURE MOVING INTO THE TN
VALLEY BY SUNSET MONDAY AND HAVE ADJUST FORECAST ACCORDINGLY. FAIR
WEATHER EXPECTED MONDAY NIGHT THROUGH TUE NIGHT WITH NEARBY HIGH
PRESSURE.
LONG TERM...WEDNESDAY THROUGH FRIDAY NIGHT
EXTENDED MODELS SHOW A SPLIT UPPER LEVEL FLOW DURING MID AND LATE
WEEK OF NEXT WEEK AND HAVE TRENDED DRIER ON WED. STRONGER SOUTHERN
STREAM SYSTEM WITH CUTOFF LOW OVER NORTHERN MEXICO INTO TX WED-THU
KEEPS MOST OF ITS HEAVIER PRECIP SOUTH CENTRAL IL WHILE WEAKER
NORTHERN STREAM SHORT WAVE MOVES EAST ACROSS THE NORTHERN TIER STATES.
BEST CHANCE OF LIGHT PRECIPITATION APPEARS TO BE OVER SE IL WED
NIGHT AND SHOULD BE WARM ENOUGH FOR RAIN THERE. BEST CHANCES OF
PRECIPITATION APPEARS TO SHIFT EAST OF IL LATE NEXT WEEK AND TRENDED
TOWARD A DRIER FORECAST. GFS AND ECMWF MODEL BOTH HAVE TRENDED
DRIER DURING THIS TIME. TEMPS TO STAY ABOVE NORMAL DURING THIS
TIME FRAME.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 AM EST SAT JAN 21 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...LOW PRESSURE ACROSS EASTERN KENTUCKY AND TENNESSEE WILL
MOVE ON TO THE EAST AS HIGH PRESSURE OVER WISCONSIN MOVES EAST
ACROSS THE GREAT LAKES LATER TODAY. AN UPPER TROUGH OVER THE WEST
COAST WILL MOVE INTO THE MID MISSISSIPPI VALLEY BY SUNDAY NIGHT AND
ACROSS THE GREAT LAKES MONDAY AND MONDAY NIGHT. IN THE EXTENDED
MODELS INDICATE A ZONAL FLOW OVER THE CENTRAL AND NORTHERN U.S.
WHICH KEEPS THE ARCTIC AIR BOTTLED UP WELL TO THE NORTH AND CAUSES
OUR TEMPERATURES TO BE QUITE MILD FOR THIS TIME OF THE YEAR. AN
UPPER TROUGH IN THE SOUTHERN STREAM WILL BRING A CHANCE OF RAIN NEXT
WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /REST OF TODAY/...
CURRENT SATELLITE DEPICTS CLEARING MOVING INTO THE NW COUNTIES A
LITTLE QUICKER THAN EXPECTED. THE RUC 925-850 MB RELATIVE HUMIDITY
FIELD APPEARS TO HAVE A GOOD HANDLE ON THIS WITH A GRADUAL
CLEARING/DECREASE IN CLOUDS ACROSS THE ENTIRE CWA THROUGHOUT THE
AFTERNOON. MODEL SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
INVERSION ACROSS THE SOUTHEASTERN CWA THROUGH AT LEAST 18Z THEN
EXTENSIVE DRYING OF THE COLUMN THIS AFTERNOON. THEREFORE...CUT SKY
GRIDS SIGNIFICANTLY ACROSS THE NORTHWEST FOR LATE THIS MORNING
WITH THE TREND SHIFTING SOUTHEAST THROUGHOUT THE AFTERNOON.
OTHER THAN THAT...CURRENT FORECAST IN GREAT SHAPE WITH ONLY MINOR
TWEAKS TO HOURLY TEMPERATURES AND WINDS TO MATCH UP WITH CURRENT
TRENDS. UPDATED GRIDS AND ZONES ALREADY SENT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST FOCUS WILL BE ON SKY COVER NEXT FEW DAYS AND RAIN CHANCES
TOWARDS THE END OF THE WEEKEND AS THE NEXT UPPER TROUGH APPROACHES.
MODELS BEGIN INCREASING LOW LEVEL MOISTURE LATER TODAY AS LOW LEVEL
FLOW BECOMES MORE SOUTHEAST AND THEN SOUTHERLY BY SUNDAY. THIS
WILL CAUSE CLOUDS TO INCREASE AGAIN BY SUNDAY. SOME CLEARING COULD
OCCUR ACROSS OUR NORTH FOR A WHILE TONIGHT AND IF IT DOES THE BOTTOM
COULD DROP ON THE TEMPERATURES WITH SNOW COVER. OTHERWISE...WILL GO
NEAR OR SLIGHTLY ABOVE MOS NUMBERS TONIGHT.
MODELS INDICATE AN INCREASING SOUTHERLY FLOW ON SUNDAY AND THIS WILL
OFTEN BREAK THE LOW LEVEL INVERSION. IF IT DOES TEMPERATURES MAY
BECOME BE A LITTLE WARMER SUNDAY. HOWEVER WITH CLOUDS BEING THE
RULE WILL GO WITH A MOS BLEND ON TEMPERATURES. WILL CONTINUE A 20
PERCENT CHANCE OF SHOWERS LATE SUNDAY AND THEN HIGH POPS ALL AREAS
SUNDAY NIGHT AS COLD FRONT APPROACHES BY MONDAY MORNING. HOURLY
TEMPERATURES MAY RISE SUNDAY NIGHT AND THEN FALL MONDAY AFTER COLD
FRONT MOVES THROUGH.
SPC HAS US IN A GENERAL RISK OF THUNDERSTORMS SUNDAY NIGHT AND EVEN
A SLIGHT RISK UP TO OUR FAR SOUTHWEST. CAPES ARE VERY
MARGINAL...BUT THERE IS A STRONG LOW LEVEL FLOW. WILL MENTION
SCATTERED THUNDERSTORMS SOUTH AND ISOLATED THUNDERSTORMS ELSEWHERE
SUNDAY NIGHT.
PRECIPITATION GRADUALLY ENDING MONDAY AFTER COLD FRONT MOVES
THROUGH. MODELS THICKNESS INDICATE A BRIEF PERIOD OF MIXED PRECIP
COULD OCCUR NORTH AND CENTRAL SECTIONS MONDAY. FINALLY DRY WEATHER
WILL BE THE RULE MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ENSEMBLES ARE SUGGESTING AN ACTIVE SPLIT FLOW TYPE PATTERN
DEVELOPING IN THE EXTENDED. APPEARS THE MAIN ITEM OF INTEREST WILL
BE WHAT HAPPENS TO A CUTOFF LOW THAT DEVELOPS OVER THE SOUTHWEST
PARTS OF THE COUNTRY EARLY NEXT WEEK AND HOW IT MAY INTERACT WITH
THE NORTHERN STREAM. THERE IS CONSIDERABLE SPREAD AMONG THE
INDIVIDUAL MEMBERS AS TO WHEN OR EVEN IF THIS SYSTEM GETS PICKED UP
BY THE NORTHERN STREAM. AT THIS POINT...ENSEMBLE DATA INDICATE AT
LEAST SOME THREAT FOR PRECIPITATION FROM ABOUT WEDNESDAY ON. WILL GO
WITH CHANCE POPS FOR THE WEDNESDAY THROUGH FRIDAY PERIODS. AT THIS
TIME...THERE ARE STILL ONLY A COUPLE OF MEMBERS INDICATING POTENTIAL
FOR SNOW...SO WILL CONTINUE TO KEEP MAJORITY OF PRECIPITATION TYPE
AS RAIN.
&&
.AVIATION /DISCUSSION FOR THE 211800Z TAFS/...
MVFR THIS AFTERNOON...VFR THIS EVENING...THEN MVFR OVERNIGHT INTO
SUNDAY.
STUBBORN MVFR CLOUDS LOOK TO GRADUALLY ERODE FROM THE NORTHEAST
DURING THE AFTERNOON HOURS. THERE IS STILL A CHANCE THAT THEY COULD
GET TRAPPED BELOW AN INVERSION AND HANG ON INTO THE EVENING...BUT
NOT CONFIDENT OF THAT SCENARIO.
IT NOW APPEARS THAT LOW LEVEL MOISTURE WILL RETURN TO THE AREA
OVERNIGHT AS WINDS BECOME SOUTHEAST. WINDS ALOFT WILL INCREASE FROM
THE SOUTH ALSO BRINGING A RETURN OF MOISTURE. WILL BRING BACK MVFR
CEILINGS BELOW BKN020 AFTER 08Z OR SO FROM SOUTH TO NORTH.
WITH THE WARM AIR RETURNING OVER THE COLD GROUND CANNOT RULE OUT
SOME FOG OR EVEN FREEZING DRIZZLE LATE TONIGHT INTO SUNDAY
MORNING...BUT CONFIDENCE NOT HIGH ENOUGH TO PUT IN TAF YET.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...HOMANN/MK
SHORT TERM...JH
LONG TERM...JS
AVIATION...50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1107 AM EST SAT JAN 21 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...LOW PRESSURE ACROSS EASTERN KENTUCKY AND TENNESSEE WILL
MOVE ON TO THE EAST AS HIGH PRESSURE OVER WISCONSIN MOVES EAST
ACROSS THE GREAT LAKES LATER TODAY. AN UPPER TROUGH OVER THE WEST
COAST WILL MOVE INTO THE MID MISSISSIPPI VALLEY BY SUNDAY NIGHT AND
ACROSS THE GREAT LAKES MONDAY AND MONDAY NIGHT. IN THE EXTENDED
MODELS INDICATE A ZONAL FLOW OVER THE CENTRAL AND NORTHERN U.S.
WHICH KEEPS THE ARCTIC AIR BOTTLED UP WELL TO THE NORTH AND CAUSES
OUR TEMPERATURES TO BE QUITE MILD FOR THIS TIME OF THE YEAR. AN
UPPER TROUGH IN THE SOUTHERN STREAM WILL BRING A CHANCE OF RAIN NEXT
WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /REST OF TODAY/...
CURRENT SATELLITE DEPICTS CLEARING MOVING INTO THE NW COUNTIES A
LITTLE QUICKER THAN EXPECTED. THE RUC 925-850 MB RELATIVE HUMIDITY
FIELD APPEARS TO HAVE A GOOD HANDLE ON THIS WITH A GRADUAL
CLEARING/DECREASE IN CLOUDS ACROSS THE ENTIRE CWA THROUGHOUT THE
AFTERNOON. MODEL SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
INVERSION ACROSS THE SOUTHEASTERN CWA THROUGH AT LEAST 18Z THEN
EXTENSIVE DRYING OF THE COLUMN THIS AFTERNOON. THEREFORE...CUT SKY
GRIDS SIGNIFICANTLY ACROSS THE NORTHWEST FOR LATE THIS MORNING
WITH THE TREND SHIFTING SOUTHEAST THROUGHOUT THE AFTERNOON.
OTHER THAN THAT...CURRENT FORECAST IN GREAT SHAPE WITH ONLY MINOR
TWEAKS TO HOURLY TEMPERATURES AND WINDS TO MATCH UP WITH CURRENT
TRENDS. UPDATED GRIDS AND ZONES ALREADY SENT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST FOCUS WILL BE ON SKY COVER NEXT FEW DAYS AND RAIN CHANCES
TOWARDS THE END OF THE WEEKEND AS THE NEXT UPPER TROUGH APPROACHES.
MODELS BEGIN INCREASING LOW LEVEL MOISTURE LATER TODAY AS LOW LEVEL
FLOW BECOMES MORE SOUTHEAST AND THEN SOUTHERLY BY SUNDAY. THIS
WILL CAUSE CLOUDS TO INCREASE AGAIN BY SUNDAY. SOME CLEARING COULD
OCCUR ACROSS OUR NORTH FOR A WHILE TONIGHT AND IF IT DOES THE BOTTOM
COULD DROP ON THE TEMPERATURES WITH SNOW COVER. OTHERWISE...WILL GO
NEAR OR SLIGHTLY ABOVE MOS NUMBERS TONIGHT.
MODELS INDICATE AN INCREASING SOUTHERLY FLOW ON SUNDAY AND THIS WILL
OFTEN BREAK THE LOW LEVEL INVERSION. IF IT DOES TEMPERATURES MAY
BECOME BE A LITTLE WARMER SUNDAY. HOWEVER WITH CLOUDS BEING THE
RULE WILL GO WITH A MOS BLEND ON TEMPERATURES. WILL CONTINUE A 20
PERCENT CHANCE OF SHOWERS LATE SUNDAY AND THEN HIGH POPS ALL AREAS
SUNDAY NIGHT AS COLD FRONT APPROACHES BY MONDAY MORNING. HOURLY
TEMPERATURES MAY RISE SUNDAY NIGHT AND THEN FALL MONDAY AFTER COLD
FRONT MOVES THROUGH.
SPC HAS US IN A GENERAL RISK OF THUNDERSTORMS SUNDAY NIGHT AND EVEN
A SLIGHT RISK UP TO OUR FAR SOUTHWEST. CAPES ARE VERY
MARGINAL...BUT THERE IS A STRONG LOW LEVEL FLOW. WILL MENTION
SCATTERED THUNDERSTORMS SOUTH AND ISOLATED THUNDERSTORMS ELSEWHERE
SUNDAY NIGHT.
PRECIPITATION GRADUALLY ENDING MONDAY AFTER COLD FRONT MOVES
THROUGH. MODELS THICKNESS INDICATE A BRIEF PERIOD OF MIXED PRECIP
COULD OCCUR NORTH AND CENTRAL SECTIONS MONDAY. FINALLY DRY WEATHER
WILL BE THE RULE MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ENSEMBLES ARE SUGGESTING AN ACTIVE SPLIT FLOW TYPE PATTERN
DEVELOPING IN THE EXTENDED. APPEARS THE MAIN ITEM OF INTEREST WILL
BE WHAT HAPPENS TO A CUTOFF LOW THAT DEVELOPS OVER THE SOUTHWEST
PARTS OF THE COUNTRY EARLY NEXT WEEK AND HOW IT MAY INTERACT WITH
THE NORTHERN STREAM. THERE IS CONSIDERABLE SPREAD AMONG THE
INDIVIDUAL MEMBERS AS TO WHEN OR EVEN IF THIS SYSTEM GETS PICKED UP
BY THE NORTHERN STREAM. AT THIS POINT...ENSEMBLE DATA INDICATE AT
LEAST SOME THREAT FOR PRECIPITATION FROM ABOUT WEDNESDAY ON. WILL GO
WITH CHANCE POPS FOR THE WEDNESDAY THROUGH FRIDAY PERIODS. AT THIS
TIME...THERE ARE STILL ONLY A COUPLE OF MEMBERS INDICATING POTENTIAL
FOR SNOW...SO WILL CONTINUE TO KEEP MAJORITY OF PRECIPITATION TYPE
AS RAIN.
&&
.AVIATION /DISCUSSION FOR THE 211430Z TAF UPDATE/...
UPDATE...AREA OF MVFR CEILINGS ACROSS OH HAS WORKED SOUTHWEST INTO
CENTRAL INDIANA. THESE CLOUDS LOOK TO PERSIST FOR AT LEAST A FEW
HOURS BEFORE BREAKING UP/MOVING OUT. THUS HAVE KEPT MVFR CEILINGS
LONGER AT KIND.
PREVIOUS DISCUSSION...
BACK EDGE OF VFR CEILINGS AROUND 050 PROGRESSING SOUTH ACROSS
NORTHERN INDIANA. MODEL DATA SUGGEST DRIER AIR WILL BE WORKING IN
FROM THE NORTH TODAY...SO EXPECT THIS TREND TO CONTINUE...WITH
CEILINGS SCATTERING OUT FROM NORTH TO SOUTH FROM LATE THIS MORNING
INTO THE AFTERNOON HOURS. STILL SOME POCKETS OF MVFR CEILINGS
AROUND 020...SO THESE LOWER CEILINGS WILL PROBABLY IMPACT THE TAF
SITES FROM TIME TO TIME THROUGH LATE THIS MORNING.
MAY SEE OCCASIONAL SURFACE WIND GUSTS 15-18KTS FROM 010-030 HEADINGS
THROUGH MIDDAY AS PRESSURE RISE MAX MOVES THROUGH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...HOMANN/MK
SHORT TERM...JH
LONG TERM...JS
AVIATION...JAS/50
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1212 PM CST SAT JAN 21 2012
.AVIATION...
CLOUD TRENDS BIGGEST CHALLENGE WITH 18Z TAFS. STRATUS WITH
MVFR CIGS CONTINUES TO BLANKET THE REGION EARLY THIS AFTN. THE
CLEARING THAT HAD WORKED INTO KDBQ FROM THE NORTH HAS SINCE
STALLED AND RETREATED BACK NWD WITH ONSET OF LLVL WARM
ADVECTION AND E/SE WINDS SFC-925 MB. SATL SHOWS WEDGE OF
CLEARING INTO CENTRAL IL WITH REGION OF DRY AIR AT 925 MB.
AS THE FLOW CONTINUES TO VEER TO E/SE THERE IS POTENTIAL
FOR THIS DRIER AIR AND CLEARING TO OVERSPREAD THE
TERMINALS... MAINLY KBRL AND POSSIBLY KMLI AND KDBQ... LATE
AFTN THROUGH THIS EVE. LATEST HRRR MODEL CAPTURES CURRENT
CLEARING TRENDS FAIRLY WELL AND DEPICTS CLEARING INTO PORTIONS OF
EASTERN IA... AND SO HAVE INTRODUCED AT KBRL WHERE CONFIDENCE
IS GREATEST AND TEMPO AT KMLI THIS EVE... BUT LEFT OUT AT KDBQ.
WILL JUST HAVE TO WATCH CLOUD TRENDS AND AMEND AS TRENDS BECOME
BETTER IDENTIFIED. ANY CLEARING LIKELY TO BE SOMEWHAT SHORTLIVED
WITH LOW CLOUDS AND MAINLY MVFR CIGS REDEVELOPING OVRNGT INTO
SUN AM WITH STRENGTHENING LOW LEVEL WARM...MOIST ADVECTION. THERE
IS WINDOW OF LLWS POTENTIAL LATE EVE INTO EARLY OVRNGT AND HAVE
ADDED MENTION IN TAFS... AS WINDS AROUND 2000 FT AGL INCREASE FROM
S/SE TO 40-45 KTS WHILE SFC WINDS GENERALLY E/SE 10-15KTS WITH
SOME GUSTS POSSIBLE. FEW FLURRIES EXPECTED BENEATH STRATUS WITH
ANY LINGERING PCPN LIKELY TRANSITIONING TO FREEZING DRIZZLE AS TEMPS
WARM JUST ABOVE AND LOSE ICE INTRODUCTION. LOW CONFIDENCE ON
COVERAGE PRECLUDES MENTION ATTIM.
&&
.PREV DISCUSSION... /ISSUED 330 AM CST SAT JAN 21 2012/
SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING HIGH PRESSURE COMPLEX OCCUPYING
MUCH OF THE UPPER MS RVR VALLEY...DOWN INTO THE CENTRAL PLAINS
WITH LARGE PRESSURE RISES NOTED TO THE LEE OF IT ACRS SOUTHEAST WI
INTO EASTERN OK ATTM. LLVL STRATUS DECK ON ITS EASTERN AND SOUTHERN
FLANK SHOWING LITTLE SIGNS OF WANTING TO BUDGE SOUTHWARD. ALOFT...
WATER VAPOR IMAGERY AND 00Z UA ANALYSIS WERE INDICATING THAT WHILE
L/W TROFFINESS WAS STARTING TO EXIT THE REGION TO THE EAST...BROAD
UPPER RIDGING WAS SLIDING ACRS THE PLAINS. FURTHER UPSTREAM...W/V
IMAGERY WAS INDICATING YET ANOTHER LARGE SLUG OF UPPER WAVE ENERGY
PUMMELING ITS WAY INTO THE WEST COAST.
SHORT TERM...TODAY AND TONIGHT...
TODAY...BACKING ELEVATED FLOW TO WARM AIR ADVECT BIG TIME TODAY
IN THE H8-H7 MB LAYER THROUGH THIS EVENING. THE SFC RIDGE CENTER
MENTIONED ABOVE WILL LOOK TO MIGRATE TO EASTERN LOWER MI BY LATE
AFTERNOON WITH SFC WINDS VEERING TO AN EAST TO SOUTHEASTERLY SFC
COMPONENT AS THE DAY PROGRESSES. SFC WINDS OF 5 TO 8 MPH PRODUCING
NEAR ADVISORY LEVEL WIND CHILLS IN THE EXTREME NORTHWEST PORTION OF
THE DVN CWA ATTM IN AREA OF SOME CLEARING...BUT NOT WIDESPREAD
ENOUGH OR TO LAST LONG ENOUGH TO WARRANT AN ADVISORY WITH THE
LIGHTER WIND REGIME IN VCNTY OF IN-BUILDING RIDGE. FEEL THE SHORT
RANGE MODELS NOT HANDLING THE LLVL STRATUS ALL THAT WELL AND THAT IT
MAY REMAIN TRAPPED UNDER THE BUILDING INVERSION FOR MUCH OF THE DAY
ESPECIALLY ACRS THE SOUTHERN HALF TO TWO THIRDS OF THE DVN CWA.
WILL SLOW THE CLEARING AN MAY KEEP MUCH OF THE CWA MOSTLY CLOUDY
INTO AT LEAST EARLY AFTERNOON. AREAS NORTH OF I80 SHOULD HAVE THE
BEST CHANCE OF CLEARING THIS AFTERNOON WITH SOME DIURNAL MIXING IN
THINNER CLOUD LAYER. WITH THE CLOUDS...WILL LEAN TOWARD THE COLDER
SIDE OF GUIDANCE HIGHS AS THE WARMING MORE REALIZED ALOFT. SOME
AREAS NOT RECOVERING MUCH WARMER THAN WHERE THEY ARE AT NOW. AREAS
THAT HAVE THE BEST CHANCE OF CLEARING ALSO HAVE THE DEEPER SNOW
COVER THUS COULD LIMIT THE HIGHS EVEN IN THOSE AREAS.
TONIGHT...EVEN IF CLOUDS CLEAR OUT IN MUCH OF THE CWA FOR A PERIOD
LATE THIS AFTERNOON AND INTO THE EVENING...EXPECT INCREASING RETURN
FLOW/WAA REGIME TO SLOSH BACK LOW CLOUDS UNDER THE INVERSION OR SET
UP A SITUATION WHERE THE LOW DECK WILL REFORM AS THE NIGHT PROGRESSES.
FCST SOUNDINGS SHOW A POTENTIAL DRIZZLE SCENARIO IN AT LEAST THE
SOUTH HALF OF THE DVN CWA AFTER 08Z SUNDAY AS BOUNDARY LAYER
MOISTURE TRAPPED UNDER THE INVERSION IN A TEMP PROFILE OF 0 TO -5C
INCREASES ENOUGH TO A DEPTH TO SUPPORT VERY LIGHT PRECIP AND THE
DRY MILDER LAYER ALOFT REMAINS AT DEEP ENOUGH WEDGE TO PREVENT
SEEDER FEEDERS. POS OMEGAS/LIFT THROUGH PART OF THE COLUMN ENOUGH
TO INDUCE SOME LIGHT PRECIP TO ALSO COMMENCE LATE TONIGHT FROM
THE WEST. ALTHOUGH EXPECT NIGHT TIME LOWS TO OCCUR DURING THE MID
EVENING WITH STEADY TO SLOWLY RISING TEMPS AFTER THAT INTO SUNDAY
MORNING...SFC TEMPS PROBABLY NOT TO RECOVER ABOVE FREEZING WHERE
THE DRIZZLE BREAKS OUT SO WILL ADD PATCHY FREEZING DRIZZLE FOR NOW
ALONG AND SOUTH OF THE I80 CORRIDOR. THINK MIXING SOUTHEAST SFC
WINDS WILL BE STRONG ENOUGH AFTER MIDNIGHT OF 10-15+ KTS...AS WELL
AS SFC DPTS NOT HIGH ENOUGH TO FOSTER WIDESPREAD DENSE FOG
DEVELOPMENT AND WILL KEEP OUT MENTION FOR NOW. ..12..
LONG TERM...SUNDAY THROUGH FRIDAY...
THE MODEL SOLUTIONS ARE COMING INTO BETTER AGREEMENT WITH THE LATE
WEEKEND SYSTEM. A POTENT S/W JUST OFF THE NORTHERN CA COAST EARLY
THIS MORNING WILL MOVE THROUGH THE WESTERN U.S. TODAY AND TONIGHT
THEN SWING NORTHEAST REACHING THE WESTERN GREAT LAKES BY LATE MONDAY.
THERE WILL BE A GOOD FEED OF GULF MOISTURE AHEAD OF THE SYSTEM...BUT
MODEL SOLUTIONS SHOW THE BULK OF THE LOW LEVEL MOIST FEED BEING
DEFLECTED TO OUR EAST AND NORTH. THE ECMWF WITH IT/S DEEPER AND
SLOWER SOLUTION PULLS SOME OF THE MOISTURE/PRECIP BACK INTO THE
EASTERN HALF OF THE CWFA. SUNDAY NIGHT AND MONDAY MORNING.
FOR SUNDAY AND SUNDAY NIGHT SOUTHERLY LOW LEVEL FLOW OVER THE NEW
SNOWPACK RAISES THE POTENTIAL FOR STRATUS/DRIZZLE...ESPECIALLY
WITH THE MID LEVELS REMAIN DRY MOST OF THE SUNDAY. INTRODUCED SOME
PATCHY DRIZZLE FOR THE LATE MORNING AND AFTERNOON HOURS OVER MUCH
OF THE AREA. TEMPERATURES OVER THE NORTHERN THIRD OF THE FORECAST
AREA...WHERE THE DEEPER SNOW IS...WILL LIKELY STAY BELOW FREEZING
UNTIL SUNDAY AFTERNOON...SO MENTIONED PATCHY FREEZING DRIZZLE IN
THE NORTH SUNDAY MORNING. CHANCE WEST TO LIKELY POPS EAST WERE
MAINTAINED FOR SUNDAY NIGHT WITH THE UPPER TROF AXIS LIFTING
THROUGH AND DEEPER MOISTURE MOVING IN. THIS SHOULD BE A RAIN
CHANGING TO SNOW SCENARIO FOR SUNDAY NIGHT AS COLDER AIR MOVES IN.
PTYPE BY LATE SUNDAY NIGHT SHOULD BE SNOW. DUE TO THE MIXED NATURE
OF THE PRECIPITATION DURING THE FIRST PART OF THE EVENT...HAVE
KEPT SNOWFALL AMOUNTS TO LESS THAN AN INCH...AND THAT SHOULD BE
OVER THE NWRN CWFA. THERE IS ALSO A LOW THREAT OF SOME FREEZING
RAIN DURING THE TRANSITION PERIOD SUNDAY EVENING ESPECIALLY IN EAST
CENTRAL IOWA.
AFTER MONDAY THE MID LEVEL FLOW BECOMES MORE ZONAL OVER THE
NORTHERN U.S. ANOTHER TROF MOVES THROUGH THE REGION TUESDAY NIGHT
AND WEDNESDAY. SO FAR THIS FEATURE APPEARS TO BE MOISTURE STARVED
AND ONLY WARRANTS LOW CHANCE POPS FOR A RAIN/SNOW MIX.
THE PREDOMINANT WEST TO EAST FLOW MID TO LATE WEEK SHOULD PREVENT
ANY INTRUSION OF THE COLD AIR OVER CANADA...RESULTING IN NEAR TO
ABOVE NORMAL TEMPERATURES. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 PM CST SAT JAN 21 2012
.AVIATION...
FOR THE 00Z TAF ISSUANCE...MAIN CONCERN IN THE AVIATION WORLD IS
WINDS. FOLLOWED RECENT HRRR GUIDANCE WHICH KEEPS SOUTHERLY WINDS 15
TO 20 KT THROUGH THE OVERNIGHT. MEANWHILE, AN APPROACHING COLD FRONT
IS EXPECTED TO TRAVERSE ACROSS THE REGION BY TOMORROW MORNING. SO
WINDS WILL VEER TO THE SW THEN FINALLY TO THE NW AFTER THE FRONT
PASSES THROUGH. ALL GUIDANCE SUPPORTS STRONG WINDS SO HAVE
INCREASED WINDS IN THE 26-32KT RANGE WITH GUSTS TO 35-40KT BY AND
AFTER 15Z TOMORROW. OTHERWISE, VFR CIGS WILL PREVAIL. -SUGDEN
&&
.PREV DISCUSSION... /ISSUED 303 PM CST SAT JAN 21 2012/
DISCUSSION...
DAYS 1-2...
THE MAIN FORECAST FOCUS WILL ON THE CHANCE FOR PRECIP DURING THE
PERIOD AND TEMPERATURES.
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE A WEAK UPPER LEVEL
RIDGE OF HIGH PRESSURE TRANSITIONING EAST ACROSS THE CENTRAL PLAINS.
MEANWHILE, AN UPPER LEVEL TROUGH OF LOW PRESSURE IS PUSHING ASHORE
IN NORTHERN CALIFORNIA. NEAR THE SURFACE, A LEE SIDE TROUGH OF LOW
PRESSURE PREVAILS ACROSS EASTERN COLORADO.
SHORT RANGE MODELS INDICATE THE UPPER LEVEL TROUGH PUSHING EAST
ACROSS THE FOUR CORNERS REGION TONIGHT AND INTO THE WESTERN HIGH
PLAINS SUNDAY BRINGING THE POSSIBILITY FOR PRECIP TO PORTIONS OF
WESTERN AND CENTRAL KANSAS BY SUNDAY AFTERNOON. A STRONG H5 VORT
MAX IS PROGGED TO PASS THROUGH WESTERN KANSAS BY 18Z IN CONJUNCTION
WITH A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH AXIS. HOWEVER
THE STRONG JET CORE ASSOCIATED WITH THE SYSTEM WILL REMAIN JUST
OFF TO OUR SOUTH ACROSS WEST TEXAS. ADDITIONALLY, LOW LEVEL
MOISTURE WILL BE LACKING WITH H85 DEWPOINTS PROJECTED TO REMAIN
WELL BELOW 0C, NOT TO MENTION A LACK OF MID LEVEL INSTABILITY.
STILL, THE NAM, GFS, AND ECMWF SHOW INCREASED MOISTURE ADVECTION
IN THE MID LEVELS ALONG WITH A POST FRONTAL H7 BAROCLINIC ZONE
PASSING ACROSS WESTERN KANSAS SUNDAY AFTERNOON. CANNOT RULE OUT A
FEW PASSING SPRINKLES OR AN ISOLATED SHOWER OR TWO ACROSS WESTERN
AND CENTRAL KANSAS. AT THE VERY LEAST INCREASED CLOUDINESS WITH
VIRGA WILL BE POSSIBLE CONSIDERING THE DRIER LOW LEVELS. WILL
LOWER POPS DOWN TO SLIGHT CATEGORY ACROSS SOUTH CENTRAL AND
EXTREME SOUTHWEST KANSAS WHILE LEAVING LOW END CHANCE CATEGORY
POPS IN NEAR THE I-70 CORRIDOR.
TEMPERATURES WILL BE MUCH WARMER TONIGHT AS LEE SIDE TROUGHING
STRENGTHENS OVERNIGHT. THIS WILL ENHANCE WARM AIR ADVECTION INTO
WESTERN KANSAS WITHIN A LOW LEVEL SOUTHWESTERLY FLOW RAISING H85
TEMPERATURES UP TO AROUND 10C TO 12C. ADDITIONALLY, MOISTURE
ADVECTION WILL INCREASE SURFACE DEWPOINTS UP INTO THE 20S(F)
ACROSS SOUTH CENTRAL AND SOUTHWEST KANSAS. LOOK FOR LOWS MAINLY
DOWN INTO THE 30S(F) WITH THE WARMER TEMPERATURES ACROSS OUR EXTREME
SOUTHWEST WHERE DOWNSLOPING WILL BE MORE OF A FACTOR TOWARD 12Z.
FOR SUNDAY, A COLD FRONT WILL QUICKLY PUSH EAST ACROSS WESTERN
KANSAS BY LATE MORNING TURNING WINDS NORTHWESTERLY. EVEN SO,
DOWNSLOPING COMBINED WITH THE INITIAL MIXING OF WARMER AIR JUST
OFF THE DECK (H85 TEMPERATURES AROUND 10C) AS THE FRONT MOVES
THROUGH, WILL ALLOW TEMPERATURES TO CLIMB WELL UP INTO THE 40S(F)
WITH SOME LOWER TO MID 50S(F) POSSIBLE BY EARLY AFTERNOON. LOW
TEMPERATURES ARE EXPECTED TO FALL BACK BELOW FREEZING SUNDAY NIGHT
AS DECREASING WINDS AND CLOUDS ACCOMPANY A SMALL AREA OF SURFACE
HIGH PRESSURE MOVING EAST ACROSS SOUTHWEST KANSAS. AS FOR MONDAY,
LEE SIDE TROUGHING WILL QUICKLY DEVELOP ACROSS EASTERN COLORADO
HELPING TO RETURN SOUTHERLY WINDS TO WESTERN KANSAS BY MONDAY
AFTERNOON. THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING
FROM JUST ABOVE 0C ACROSS CENTRAL KANSAS TO NEAR 5C ALONG THE
COLORADO BORDER. ALONG WITH PLENTY OF SUNSHINE, LOOK FOR HIGHS UP
INTO THE 50S(F) MONDAY.
WINDS WILL BE FAIRLY STRONG OUT OF THE NORTHWEST LATE SUNDAY MORNING
AND AFTERNOON. ALL MODELS SHOW H85-H7 WINDS AROUND 40 TO 50KT JUST
BEHIND THE FRONT. WITH SOME MIXING EXPECTED AS THE FRONT MOVES
THROUGH, WIND ADVISORY WINDS ARE EXPECTED TO BE MET. HOWEVER,
LESS CERTAINTY REMAINS AS TO WHERE A BRIEF HIGH WIND GUST MAY
OCCUR TO WARRANT A HIGH WIND WARNING. WILL DEFER TO THE NEXT SHIFT
WITH A HIGH WIND WATCH ALREADY ALERTING THE PUBLIC TO THE POTENTIAL
OF STRONGER WINDS.
DAYS 3-7...
FOR TUESDAY AN UPPER LEVEL SHORTWAVE TROUGH WILL BE GOING THROUGH
THE NORTHERN PLAINS WHILE AN UPPER CLOSED LOW CONTINUES TO DIG INTO
SOUTHERN NEW MEXICO. KANSAS WILL BE IN BETWEEN THESE TWO SYSTEMS
WITH ONLY SOME HIGH LEVEL CLOUDINESS EXPECTED. LOWS ON TUESDAY
MORNING WILL RANGE FROM THE MID TO UPPER 20S. HIGHS WILL BE IN THE
MID TO UPPER 40S, TO AROUND 50 SOUTHEAST FA AROUND MEDICINE LODGE.
FOR WEDNESDAY ANOTHER NORTHERN BRANCH WAVE MOVES ACROSS THE PLAINS
WITH WINDS SHIFTING NORTHERLY WHILE THE SOUTHERN UPPER LOW GETS
CUTOFF IN NORTHERN MEXICO. NEAR THE WIND SHIFT IN THE SOUTHEAST
AROUND MEDICINE LODGE THE DEWPOINTS RISE INTO THE MID 30S WITH A
SLIGHT CHANCE FOR RAIN EARLY WEDNESDAY MORNING. NOT MUCH CHANGE IN
THE TEMPERATURES FOR WEDNESDAY WITH MORNING LOWS IN THE UPPER 20S
NORTH TO MID 3OS SOUTHEAST. HIGHS WILL BE AROUND 50. ON THURSDAY DRY
NORTHWESTERLY FLOW CONTINUES WITH A LEE TROUGH DEVELOPING. LOWS WILL
BE AROUND 30 WITH WARMER HIGHS IN THE MID 50S. FOR FRIDAY A STRONGER
NORTHERN BRANCH SHORTWAVE TROUGH MOVE INTO THE NORTHERN AND CENTRAL
PLAINS WITH COOLER HIGH PRESSURE MOVING INTO THE PLAINS. MORNING
LOWS WILL BE IN THE LOW TO MID 30S WITH HIGH TEMPS A BIT COOLER AND
AROUND 50. ON SATURDAY THE EC MODEL HAS A DEEPER TROUGH MOVING
THROUGH THE UPPER MIDWEST IN THE MORNING, WHILE THE GFS IS FLATTER
WITH A MORE ZONAL FLOW. LOWS LOOK TO BE IN THE MID 20S NORTH TO
AROUND 30 SOUTH WITH COOLER HIGHS IN THE MID 40S.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 30 50 22 53 / 0 30 0 0
GCK 32 50 20 52 / 0 30 0 0
EHA 37 52 23 53 / 0 20 0 0
LBL 35 53 20 55 / 0 20 0 0
HYS 28 48 20 50 / 0 30 0 0
P28 28 55 25 55 / 0 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CST /9 AM MST/ TO 4 PM CST /3 PM MST/
SUNDAY FOR KSZ030-031-045-046-061-064>066-074-078>081-084-
088>090.
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ043-
044-061>063-074>077-084>087.
HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR
KSZ043-044-062-063-075>077-085>087.
&&
$$
FN99/99/36
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1039 AM MST SAT JAN 21 2012
.DISCUSSION...
420 AM MST SAT JAN 21 2012
MAIN FORECAST PROBLEM WILL BE THE WINDS THROUGH SUNDAY BUT MANY
OTHER CONCERNS ARE JUST BELOW THE WINDS. SATELLITE SHOWING AN
ACTIVE/PROGRESSIVE WAVE TRAIN FROM THE PACIFIC INTO THE WESTERN
ATLANTIC. BROAD UPPER TROUGH REMAINS IN PLACE OVER THE PACIFIC WITH
A STRONG SHORTWAVE TROUGH APPROACHING THE WEST COAST. ALSO BIG LOW
LEVEL TEMPERATURE GRADIENT SLIDING BACK AND FORTH ACROSS THE AREA.
AT JET LEVEL...EXTREMELY STRONG JET OVER THE EASTERN PACIFIC BEHIND
INCOMING TROUGH. BASED ON WHAT OBSERVATIONS ARE OUT THERE...THE
MODELS ARE UNDERDOING THE STRENGTH OF THE NEAR 200 KNOT JET. BASED
ON AVAILABLE DATA...THE GFS AND NAM LOOK TO HAVE THE BEST STRENGTH
BUT THE NAM/CANADIAN HAVE BEST ORIENTATION. OVER THE COUNTRY...THE
NAM AND CANADIAN HAVE THE BEST HANDLE ON THE JET THAT STARTED NEAR
OUR AREA LAST NIGHT. THE OTHER MODELS TENDED TO BE TOO FAR EAST.
SATELLITE AND UPPER AIR WOULD SUPPORT THE ECMWF/CANADIAN BEING THE
BEST AT MID LEVELS. MODELS TENDED TO BE TOO MOIST AT MID LEVELS
WITH THE CANADIAN AND UKMET DOING THE BEST. MODELS CONTINUING TO
HAVE TROUBLE WITH THE LOW LEVEL THERMAL FIELD. OVERALL THE UKMET AND
CANADIAN WAS DOING A LITTLE BETTER THAN THE GFS...ESPECIALLY WITH
THE POSITION OF THE COLD POOL TO OUR NORTH AND EAST.
TODAY/TONIGHT...NEWER GUIDANCE HAS COME IN A LITTLE STRONGER WITH
THE WINDS. MODELS SHOW LITTLE TO NO MIXING TODAY WITH LOUSY LOW
LEVEL LAPSE RATES. WHICH AM NOT ENTIRELY SURE ABOUT. INITIAL
QUESTION TO HELP WITH THAT WILL BE HOW MUCH CLOUD COVER WILL MOVE IN
TODAY. IMPRESSIVE CLOUD SHIELD OUT TO OUR WEST. THE BETTER MODELS IN
REGARDS TO THIS MOISTURE WOULD SAY THAT THE CLOUDS REALLY DO NOT
THICKEN UP UNTIL THIS AFTERNOON. HOWEVER...DESPITE THE LACK OF
MIXING WHAT MAY BE THE MAIN DRIVING FORCE BEHIND THESE WINDS COULD
THE TIGHTENING PRESSURE GRADIENT AND PRETTY HIGH 3 HOUR PRESSURE
FALLS THROUGH THE AFTERNOON. GOING BY WHAT LIMITED MIXING BUFKIT
SHOWS...WINDS LOOK TO REACH ADVISORY CRITERIA. IT WILL BE CLOSE BUT
CHOSE TO ISSUE A WIND ADVISORY FOR ALL BUT THE FAR EASTERN TWO
COUNTIES. ADVISORY MAY BE MARGINAL FOR THOSE EASTERN COUNTIES BUT
WILL BE PLAYING THIS ON THE SAFE SIDE.
MODELS HAVE HAD A HORRIBLE TIME WITH TEMPERATURE GRADIENT ACROSS THE
AREA. THICKENING CLOUD COVER WILL MAKE THIS EVEN MORE PROBLEMATIC.
LOW LEVEL THERMAL PROFILES CLUSTER AROUND A LITTLE WARMER
TEMPERATURES THAN WHAT IS IN THERE. CANADIAN SURFACE TEMPERATURE
MATCHES UP WELL WITH WHAT THE HRRR IS SHOWING. SO WARMED UP
TEMPERATURES SOME IN LINE WITH THOSE MODELS.
STRONG INCOMING SYSTEM BEGINS TO AFFECT THE AREA LATE TONIGHT.
DEEPER MOISTURE AND LIFT ALONG WITH DECENT LAPSE RATES COME INTO
THE WEST LATE. MORE MODEL QPF SHOWING QPF IN THIS AREA AND SEEMS
REASONABLE CONSIDERING THE LIFT AND INSTABILITY. QUESTION THEN
BECOMES PHASE. LOW LEVEL THERMAL GUIDANCE AND SOUNDING SHOW VERY
MILD OVERNIGHT TEMPERATURES IN ADVANCE OF THE SYSTEM. THE ONLY
PLACE THAT LOOKS TO BE NEAR FREEZING IS IN THE EAST WHERE
PRECIPITATION IS NOT EXPECTED AT THIS TIME. RAISED MINS ACROSS THE
REMAINDER OF THE AREA. CONSIDERING THE POSSIBILITY OF A LITTLE MORE
INTENSE PRECIPITATION AND BEING A LITTLE WARM...DID A RAIN AND SNOW
MIX IN THE FAR WEST WITH SPRINKLES TO THE EAST OF THERE.
SUNDAY/SUNDAY NIGHT...LEFT FRONT QUADRANT OF THE JET STARTS OUT OVER
THE EASTERN HALF OF THE AREA AT 12Z AND THEN IT QUICKLY MOVES EAST.
STRONG UPPER TROUGH MOVES THROUGH DURING THE DAY. BASED ON
SATELLITE...STRONG JET ASSOCIATED WITH THE SYSTEM...AND STRONG PV
ANOMALY INDICATED...BELIEVE THE MODELS ARE UNDERDOING THE STRENGTH OF
THE SYSTEM. COMBINATION OF STRONG LIFT/PV ANOMALY AND FAVORABLE
THETA-E LAPSE RATES...WILL BRING A GOOD CHANCE OF A LIGHT MEASURABLE
PRECIPITATION EVENT TO THE AREA. BASED ON THE PREVIOUS REASONING...
GEFS PROBABILITIES...AND LOCAL POP PROGRAM...RAISED POPS OVER THE
ENTIRE FORECAST AREA...ESPECIALLY IN THE EAST. DAY SHIFT WILL HAVE
TO LOOK AT RAISING THESE POPS EVEN MORE. PHASE REMAINS A PROBLEM.
MODELS DO NOT SHOW A LOT OF COLD AIR. IT IS POSSIBLE WITH THE MOST
INTENSE PRECIPITATION SNOW COULD MIX WITH THE RAIN IN THE MORNING.
AT THIS TIME KEPT THE MIXED PHASE IN THE MORNING WITH ALL RAIN IN
THE AFTERNOON.
HOWEVER...WHAT LOOKS TO BE THE MAIN STORY WILL ONCE AGAIN BE THE
WINDS. STRONG SUBSIDENCE BEHIND THE WAVE/EXITING PRECIPITATION
COMBINED WITH VERY GOOD LAPSE RATES AND 3 HOUR PRESSURE RISES
SHOULD BRING A HIGH END WIND ADVISORY EVENT TO THE ENTIRE AREA.
HOWEVER...STRONGEST 3 HOUR PRESSURE RISES ARE OUT AHEAD OF THE MAIN
SUBSIDENCE. WHAT IS CONCERNING IS THAT IF PARAMETERS CAN COME
TOGETHER A LITTLE BETTER...IT IS POSSIBLE THAT WARNING CRITERIA
COULD BE MET. DAY SHIFT WILL HAVE TO LOOK AT THIS AGAIN...AND CHOOSE
THE APPROPRIATE HIGHLIGHT. CHOSE TO GO SLIGHTLY BELOW THE GUIDANCE
WHICH WAS IN PRETTY CLOSE AGREEMENT. PRECIPITATION SHOULD BE DONE BY
THE NIGHT AND WILL PROBABLY COOL BELOW GUIDANCE.
MONDAY/MONDAY NIGHT...QUESTION WILL BE HOW MUCH TO WARM
TEMPERATURES. WILL HAVE A COLD START PLUS EXITING SURFACE HIGH AND
DEVELOPING LEE TROUGH WILL CAUSE THE WINDS TO BE MORE FROM AN
UPSLOPE DIRECTION. SO TRENDED SLIGHTLY COOLER THAN THAN GUIDANCE.
NEXT FRONT STARTS MOVING THROUGH DURING THE NIGHT AND MADE NO
CHANGES TO THE TONIGHT PERIOD.
BULLER
TUESDAY THROUGH FRIDAY...SHORTWAVE RIDGE BREAKS DOWN AS TROUGH OVER
GREAT BASIN SHIFTS EAST ACROSS THE INTERMOUNTAIN WEST. GUIDANCE IN
GENERAL AGREEMENT ON H5 CLOSED LOW DEVELOPING OVER NEW MEXICO
TUESDAY MORNING...WITH SHORTWAVE TROUGH KICKING EAST ACROSS THE CWA
BY 18Z TUESDAY. MOISTURE ISNT VERY IMPRESSIVE WITH THIS SYSTEM...
WITH CLOSED LOW KEEPING GULF MOISTURE MUCH FURTHER SOUTH. HOWEVER
THERE IS A NARROW WINDOW WHERE LARGE SCALE ASCENT AND LIMITED
MOISTURE ADVECT IS PRESENT OVER PARTS OF THE CWA. FOR NOW HAVE KEPT
SLIGHT CHANCE POPS ACROSS WESTERN LOCATIONS DURING THE DAY TUESDAY...
AND IN THE FAR EASTERN DURING THE EVENING. SHORTWAVE RIDGE DEVELOPS
ACROSS THE SW US WEDNESDAY AND THURSDAY AS TROUGH SHIFTS EAST...WITH
NW FLOW JUST NORTH OF THIS FEATURE OVER THE CWA. LEE TROUGH DEVELOPS
THURSDAY BENEATH THIS PATTERN WITH S/SW FLOW AT THE SURFACE
SUPPORTING A BRIEF RETURN TO TEMPS IN THE 50S/NEAR 60 THURSDAY
AFTERNOON. NW FLOW PERSISTS THROUGH FRIDAY...WITH SHORTWAVE
TROUGH PUSHING EAST TOWARDS THE PLAINS FRIDAY NIGHT. GUIDANCE IS ALL
OVER THE PLACE ON THE EXACT TRACK OF THIS FEATURE...SO NOT ENOUGH
CONFIDENCE TO ADD PRECIP AT THIS POINT.
DR
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
1039 AM MST SAT JAN 21 2012
FOR THE 18Z TAFS...GUSTY WINDS WILL IMPACT THE TERMINALS TODAY AND
TOMORROW...AND THERE IS ALSO THE POSSIBILITY OF PRECIPITATION
TOMORROW. FOR TODAY...GIVEN THE POSITION OF KGLD RELATIVE TO THE LEE
TROUGH...HAVE INCLUDED STRONGER WINDS AT KGLD COMPARED TO KMCK.
WINDS WILL WEAKEN TONIGHT...BUT GUSTS ARE EXPECTED TO CONTINUE FOR A
FEW HOURS TONIGHT AT KGLD AS THE LEE TROUGH WEAKENS. AS AN UPPER
TROUGH MOVES OVER THE AREA...WINDS WILL SHIFT TO NORTHWESTERLY AND
INCREASE DURING THE MID MORNING. THE TROUGH WILL ALSO BRING THE
POSSIBILITY OF A LIGHT RAIN/SNOW MIX TO THE TERMINALS. CONFIDENCE
ABOUT PRECIP IS HIGHER AT KMCK...AND WHILE NAM SOUNDINGS ALSO
SUPPORT MVFR CEILINGS AT KMCK...IT IS MORE LIKELY THAT CEILINGS WILL
REMAIN IN THE LOW VFR RANGE. THE WIND COULD CAUSE VISIBILITIES LOWER
THAN VFR WHEN COMBINED WITH LIGHT PRECIP...ESPECIALLY IF SNOW ENDS
UP DOMINATING...BUT CONFIDENCE TOO LOW AT THIS TIME TO INCLUDE
SUB-VFR CONDITIONS.
CJS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
KSZ001>003-013>015-027>029-041-042.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ013-027-041.
NE...WIND ADVISORY UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
NEZ079>081.
CO...WIND ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ090>092.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ252>254.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 AM CST SAT JAN 21 2012
...UPDATE TO AVIATION...
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
MVFR STRATUS DECK HAS BEGUN TO VERY SLOWLY ERODE ON THE WESTERN
FRINGES AND EXPECT THE CIGS TO SCATTER OUT FIRST AT MHK AND THEN
AT TOP/FOE THIS AFTERNOON. EXACT TIMING IS UNCERTAIN BUT
HIGHLIGHTED MOST LIKELY TIMING WITH A TEMPO GROUP. EXPECT A PERIOD
OF VFR CONDITIONS FROM THAT POINT THROUGH 09Z-11Z WHEN LOW STRATUS
IS AGAIN EXPECTED TO DEVELOP ALONG WITH SOME MINOR VIS RESTRICTIONS.
HIGHER CONFIDENCE IN CIGS AT TOP/FOE THAN MHK BUT POTENTIAL EXISTS
FOR MVFR...TO PERHAPS IFR CIGS BY SUNRISE SUNDAY MORNING. THIS
SHOULD THEN LAST THROUGH THE END OF THE TAF PERIOD.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1201 PM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE GULF OF MAINE TODAY. HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION SUNDAY AND MOVE EAST OF
THE AREA EARLY MONDAY.
&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE2: WITH SNOW JUST WEST OF OUR FORECAST AREA, WILL INCREASE POPS TO
LIKELY ALONG THE COAST FOR THE REMAINDER OF THIS AFTERNOON. ANY
SNOW ACCUMULATION STILL APPEARS TO BE LESS THAN AN INCH.
UPDATE1: HRRR MODEL STILL INDICATING NORTHERN EDGE OF SNOW WILL
MOVE ACROSS DOWNEAST THIS AFTERNOON WITH A PERIOD OF LIGHT SNOW SO
WILL KEEP POPS GOING FOR DOWNEAST TODAY. ANY SNOW ACCUMULATION
WILL BE LESS THAN AN INCH.
PREV DISC: LOW PRESSURE WILL TRACK SOUTH OF NEW ENGLAND TODAY. THE
PRECIPITATION FROM THIS SYSTEM IS ONLY EXPECTED TO EFFECT THE
SOUTH. HAVE USED A BLEND OF THE NAM12...GFS40 AND SREF FOR POPS.
WILL ADJUST THIS BLEND MANUALLY TO KEEP LOWER POPS FURTHER SOUTH.
HAVE USE A BLEND OF NAM12 AND GFS40 FOR WIND. HIGH PRESSURE WILL
BUILD IN FROM THE NORTHWEST SUNDAY. FOR TEMPERATURE AND DEW POINT
WILL USE GMOS AND ADJUST LOW TEMPERATURE LOWER SUNDAY MORNING TO
ACCOUNT FOR RADIATIONAL COOLING. FOR QPF HAVE BLENDED THE NAM12
AND GFS40.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A THAW LOOKS TO BE IN ORDER COME MONDAY W/LOW PRES MOVING THROUGH
THE WESTERN QUEBEC PROVINCE.
A NICE DAY IS IN STORE FOR SUNDAY W/A A GOOD DEAL OF SUNSHINE AS
HIGH PRES SETTLES RIGHT ACROSS THE STATE. TEMPERATURES WILL BE
WARMER THAN THEY WERE SATURDAY HITTING THE MID/UPPER TEENS NORTH
AND LOW TO MID 20S ACROSS THE CENTRAL AND DOWNEAST REGION. HIGH
PRES WILL SLIDE E SUNDAY NIGHT W/A RETURN FLOW FROM THE ESE
BEGINNING TO SETUP. HIGH CLOUDINESS IS SHOWN BY THE GFS AND THE
NAM TO MOVE ACROSS THE REGION SUNDAY NIGHT AS WAA BEGINS TO SET
UP. TEMPERATURES WILL DROP BACK IN THE EVENING AND THEN ARE SHOWN
TO LEVEL OFF BEFORE RISING EARLY MONDAY MORNING. ATTM, STAYED
CLOSE TO THE DAYCREW/S ASSESSMENT OF SINGLE NUMBERS ACROSS THE
NORTHERN AND WESTERN SECTIONS AND LOW TO MID TEENS FOR THE CENTRAL
AND DOWNEAST REGIONS. THIS WILL NEED TO BE LOOKED AT AGAIN AS ANY
PROLONGED CLEARING WILL ALLOW FOR TEMPERATURES TO FALL OFF MORE
BEFORE LEVELING OFF.
INCREASING CLOUDS FOR MONDAY W/A SSE FLOW SETTING UP AND MOISTURE
GETTING PULLED NORTHWARD. STRATUS LOOKS LIKE IT COULD ADVECT IN
W/THIS SETUP. ECMWF HOLDS ON TO LLVL COLD AIR LONGER W/DAMMING
ACROSS THE ENE SECTIONS OF THE CWA. THE NAM AND THE CANADIAN
HEMISPHERIC INDICATE THIS TO BE THE CASE AS WELL. THE GFS BREAKS
DOWN THE DAMMING QUICKER. THEREFORE, DECIDED TO CUT BACK MAXES ON
MONDAY W/THE SETUP PLUS WARMING TENDS TO HOLD BACK A BIT W/A SE
FLOW GETTING STARTED(HISTORICALLY SPEAKING). PRECIP CHANCES WERE
HELD BACK SOME W/RIDGE HOLDING IN LONGER. LOOKS LIKE SOME MIX OF
RAIN/SNOW AND SLEET INITIALLY LATE MONDAY ACROSS THE NORTH AND
WEST W/RAIN OVER THE DOWNEAST AND POINTS SOUTH. TEMPERATURES WILL
CONTINUE TO SLOWLY RISE MONDAY NIGHT AND THIS WILL BE ADDRESSED
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE MAIN CHALLENGE THIS TERM WILL BE TEMPERATURES AND PRECIP TYPE
EARLY IN THE TERM.
OCCLUSION IS SHOWN BY THE LONG RANGE GUIDANCE INCLUDING THE
CANADIAN HEMISPHERIC TO LIFT NORTHWARD MONDAY NIGHT AND SWING
ACROSS THE REGION ON TUESDAY. THE NAM/ECMWF SHOW A WEAK LOW
DEVELOPING ON THE OCCLUSION AND MOVING ACROSS EASTERN MAINE. THIS
COULD ENHANCE PRECIP AND POSSIBLY CUT OFF SIGNIFICANT WARMING
WHILE THE CANADIAN HEMISPHERIC HINTS AT SOMETHING SIMILAR BUT IS
FURTHER WEST WHICH WOULD ALLOW FOR MORE WARMER AIR TO BE PULLED
NORTHWARD. THE GFS AND ITS ENSEMBLE MEAN KEEP THE OCCLUSION
SWEEPING THROUGH THE REGION ON TUESDAY. DAYCREWS POPS LOOKED GOOD
AND MODIFICATIONS MADE ONLY FOR PLACEMENT AND BROUGHT THE VALUES
UP SOME BUT STILL IN THE LIKELY TO CATEGORICAL RANGE. SOME SLEET
AND RAIN POSSIBLE ACROSS THE FAR NORTH EARLY MONDAY EVENING BUT
THE COLUMN SHOULD BE WARM ENOUGH TO ALLOW FOR RAIN. AN INTERESTING
NOTE IS THAT THE HEMISPHERIC GUIDANCE SHOWS 40S AND 50S TUESDAY
AFTERNOON. THIS IS THE ONLY GUIDANCE THAT IS SHOWING THIS TO BE
THE CASE. A BLEND OF THE GMOS AND GFS WAS USED FOR THE TEMPERATURES
WHICH INDICATE A WARMER SCENARIO FOR TUESDAY W/TEMPERATURES
HITTING THE MID AND UPPER 30S NORTH AND WEST AND 40S CENTRAL AND
DOWNEAST. THE FRONT CLEARS THE REGION BY TUESDAY EVENING W/THE
GRADUAL COOL DOWN AND WHATEVER PRECIP IS LEFTOVER TRANSITIONING TO
SNOW SHOWERS MAINLY NORTH & WEST. HELD BACK THE COOLING FOR ABOUT
6 HRS AS PAST EVENTS SIMILAR TO THIS SHOW MODELS TO BE TOO FAST
W/BRINGING THE COLDER AIR BACK IN BEHIND THE OCCLUSION. UPPER TROF
WILL NEED TO MOVE THROUGH FOR THAT TO HAPPEN. GMOS/GFS TEMPERATURES
WERE BLENDED FOR TUESDAY NIGHT AS WELL.
THE ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA ON
WEDNESDAY W/MUCH COLDER TEMPERATURES FOR MID TO LATE WEEK AS
ADVERTISED BY THE GFS AND ECMWF. GMOS WAS USED FROM WEDNESDAY
ONWARD BUT PULLED BACK POPS TO BELOW 20% THURSDAY INTO FRIDAY
W/HIGH PRES BUILDING ACROSS THE REGION. ECMWF BRINGS A LOW ACROSS
THE GULF OF MAINE LATE NEXT FRIDAY W/AN INVERTED TROF HANGING BACK
ACROSS THE REGION SIMILAR TO THIS PASS EVENT YESTERDAY(FRIDAY1/20).
THIS WOULD MEAN POTENTIAL SNOW FOR THE CWA. THE ECMWF IS THE ONLY
GUIDANCE SHOWING THIS AS THE GFS AND ITS ENSEMBLES SHOW THE LOW TO
DEVELOP WELL SOUTH OF THE CWA. STILL PLENTY OF TIME TO LOOK AT
THIS AS THIS IS DAY 7!.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MAINLY VFR CONDITIONS TODAY AND TONIGHT EXCEPT FOR A
PERIOD OF MVFR IN LIGHT SNOW ACROSS DOWNEAST TERMINALS LATE
MORNING INTO EARLY AFTERNOON.
SHORT TERM: VFR FOR SUNDAY AND THEN POTENTIAL FOR MVFR/IFR ON
MONDAY W/SSE FLOW SETTING UP W/MOISTURE GETTING PULLED IN FROM THE
ATLC OCEAN. MONDAY NIGHT INTO TUESDAY LOOK TO BE IFR AND EVEN LIFR
AT LEAST EARLY IN THE DAY. LLWS ALSO A POSSIBILITY EARLY TUESDAY.
&&
.MARINE...
NEAR TERM: AS LOW PRESSURE MOVES SOUTHEAST OF THE WATERS, MAY
HAVE A PERIOD OF SCA WINDS ON THE BACK SIDE OF THE LOW PRESSURE
TONIGHT MAINLY OVER OUR OUTER WATERS.
SHORT TERM: SCA CONDITIONS BY MONDAY W/POTENTIAL FOR A BRIEF
PERIOD OF GALES EARLY TUESDAY W/THE OCCLUSION. USED THE NAM12 AND
GFS THROUGH EARLY TUESDAY WHICH SUPPORTS GUSTS HITTING 35+ KTS
FROM 12-18Z TUESDAY AS LLVL JET OF 50 KTS IS SHOWN TO PASS OVER
THE WATERS. HELD ONTO THE DAYCREWS WAVE HEIGHTS OF INCREASING SEAS
TO 10-13FT BY TUESDAY W/SSE FLOW. FOLLOWED WNAWAVE FROM TUESDAY
NIGHT INTO WEDNESDAY SHOWING A DECREASING TREND IN SEAS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...FOSTER/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...FOSTER/MIGNONE
MARINE...FOSTER/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 PM EST SAT JAN 21 2012
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN ARCTIC VORTEX CEMTERED OVER HUDSON BAY ASSOCIATED
WITH RECENT INTENSE CHILL AND PROGRESSIVE UPR RDG SHIFTING E THRU
THE NRN PLAINS. SFC/H85 RDG AXIS HAS BROUGHT RELATIVELY TRANQUIL WX
TO THE FA TDAY WITH MID LVL DRY AIR SHOWN ON THE 12Z GRB RAOB. TEMPS
HAVE RISEN STEADILY FM MRNG LOWS ARND -25F OVER THE INTERIOR W. SOME
LES LINGERS EARLY THIS AFTN OVER THE KEWEENAW AND IN AREAS WELL E OF
MQT WITH H85 TEMPS STILL AOB -15C...BUT BACKING LLVL FLOW TO THE SW
THAT SIGNALS A RETREAT OF THE ARCTIC AIR IS CAUSING THE SHSN TO
DRIFT TO THE NE. IN FACT...WAD MID CLD BEST DEPICTED BY THE RH SHOWN
ON THE 12Z NAM 290-295K ISENTROPIC SFCS/H6-7/ AND WELL IN ADVANCE OF
SHARP H85 WARM FNT PUSHING THRU THE NRN PLAINS IS ALREADY MOVING FM
NRN MN INTO THE WRN CWA. BUT GENERALY DRYNESS OF THE 12Z INL RAOB IS
PREVENTING ANY PCPN. SOME -SN IS SHOWING UP NEAR LK WINNIPEG. TO THE
S...THERE IS QUITE A BIT OF LO CLD S OF THE HI CENTER IN WI...AND
THIS ST/SC IS STARTING TO STREAM NWD INTO SW MN. FARTHER W...12Z H85
TEMPS WERE UP TO 6C IN THE LEE OF THE ROCKIES BEHIND THE WARM FNT. A
VIGOROUS SHRTWV IS DIGGING SEWD INTO THE SW STATES. THERE HAVE BEEN
A FEW LTG STRIKES NEAR THE TRACK OF THIS FEATURE...AND NEARBY PIREPS
INDICATE H3 WIND SPEEDS UP TO 175KT WITHIN SUPPORTING UPR JET THAT
IS WELL DEFINED ON WV IMAGERY.
&&
.SHORT TERM DISCUSSION /TNGT AND SUN/...
MAIN FCST CONCERNS IN THIS PERIOD ARE IMPACT OF RETURNING WARM AIR
IN VIGOROUS WAD PATTERN THAT WL SET UP IN RETURN SLY FLOW BTWN
DEPARTING HI PRES RDG TO THE E AND DVLPG LO PRES IN THE PLAINS
ASSOCIATED WITH VIGOROUS HGT FALLS IN ADVANCE OF SHRTWV NOW MOVING
INTO THE SW STATES.
TNGT...WITH STRENGTHENING LLVL SLY FLOW...EXPECT ANY LES NEAR LK SUP
TO DRIFT OFFSHORE BY LATE IN THE AFTN. SINCE THE AIRMASS WL STILL BE
COLD ENUF FOR LES EARLY WITH H85 TEMPS ARND -12C...GOING FCST OF
SOME LK CLD/SHSN OFF LK MI INTO THE FM ISQ-ERY STILL LOOKS ON TRACK.
BUT THIS PCPN SHOULD DIMINISH AS TEMPS RISE THRU THE NGT. IN FACT...
H85 WIND INCRSG UP TO 50KTS TOWARD WRN LK SUP BY 12Z SUN ARE FCST TO
PUSH H85 TEMPS NEAR 0C IN THAT AREA TOWARD DAYBREAK. THIS
STRENGTHENING SSW FLOW WL ALSO DRAW THE LO CLD NOW WELL TO THE S
INTO THE WRN AND CNTRL CWA. BUT DOWNSLOPE NATURE OF THE FLOW OVER
THE W AND NCNTRL SHOULD RESULT IN SOME DISSIPATION OF THIS CLD
COVER. TO THE NW...THE AREA OF SN NOW NEAR LK WINNIPEG WL LIKELY
SHIFT NEAR ISLE ROYALE WITH PERSISTENT ISENTROPIC ASCENT SHOWN ON
THE 290-295K SFCS...MORE SATURATED PROFILE DOWN TO THE SFC...AND
INCRSG UPR DVGC IN RRQ OF H3 JET MAX IN ONTARIO AND IN EXIT REGION
OF ANOTHER UPR JET EMERGING ON THE E SIDE OF DEEPENING UPR TROF IN
THE PLAINS. WITH 5-6K FT DEEP DRY WEDGE SHOWN ON FCST SDNGS FOR
CMX...SUSPECT THE BULK OF THIS PCPN WL REMAIN TO THE NW OF THE
KEWEENAW. SO CUT POPS INTO THE CHC CATEGORY FOR THAT AREA WITH HIER
POPS TO THE N. EXPECT THE LOWEST TEMPS EARLY TNGT...WITH THE MERCURY
RISING LATER AS INCRSG S WIND ADVECTS MORE LLVL MSTR INTO THE AREA.
TENDED TO LOWER EARLY EVNG TEMPS OVER THE INTERIOR CNTRL BEFORE
ARRIVAL OF THICKER CLD COVER/ONSET OF STRONGER WINDS CAUSES TEMPS TO
RISE OVERNGT.
SUN...THE WX WL BE DOMINATED BY THE ARRIVAL OF INCRSG LLVL MSTR IN
STEADY SSE WIND BTWN DEPARTING HI PRES RDG AND DVLPG LO IN THE
PLAINS. ALTHOUGH CONTINUED WAD WL TEND TO RESULT IN INCRSG MID LVL
MSTR AS WELL...MODEL GUIDANCE INDICATES A PERSISTENT DRY WEDGE
CENTERED ARND H85 THRU THE DAY BTWN THE LLVL AND HIER LVL
MOISTENING. MAINTAINED MAINLY SCHC POPS FOR LARGER SCALE PCPN...HIER
TO THE NW. ANY PCPN WL LIKELY BE SN AND PSBLY SLEET WITH WARM
WEDGE/H85 TEMPS POTENTIALLY UP TO 5C IN THE DRY LYR THAT MIGHT MELT
SN FLAKES ABV RESIDUAL COLD AIR JUST ABV THE SFC...WHERE TEMPS ARE
FCST TO REMAIN AS LO AS -6C TO -8C. ALSO INCLUDED MENTION OF FZDZ
MAINLY OVER THE SCNTRL WHERE GUIDANCE SHOWS INCRSG SFC DEWPTS IN
AREA OF UPLSOPE SSE FLOW. LIMITING FACTOR WL BE FAIRLY HI SFC DEWPT
DEPRESSIONS NOW OBSVD TO THE S/STRONG WINDS THAT MIGHT MAINTAIN A
SLIGHT INVERTED V LLVL THERMAL/MSTR PROFILE.
.LONG TERM /SUNDAY NIGHT THROUGH NEXT SATURDAY/...
DEEPENING LOW PRESSURE OVER THE UPPER LAKES AND MIXED PRECIPITATION
ISSUES IS THE MAIN CONCERN OF THE LONG TERM.
BY SUNDAY EVENING...SHORTWAVE TROUGH WITH AT LEAST TWO EMBEDDED
SHORTWAVES/PV ANOMALIES WILL BE OVER THE CNTRL PLAINS. MAJORITY OF
MODELS AGREE IN THIS IDEA. 12Z NAM IS ON ITS OWN SHOWING STRONGER
PIECE OF ENERGY SHOOTING NORTH INTO MN. ALL OTHER GUIDANCE...SAVE THE
SREF WHICH HAS MANY NAM MEMBERS WITHIN IT...KEEPS STRONGEST ENERGY
MORE OVR SOUTHERN PLAINS. BASED ON POSITION OF UPPER JET AHEAD OF
TROUGH...THINK NAM IS TOO STRONG WITH SHORTWAVE OVR MN. THIS LEADS
TO A MUCH FARTHER NORTH TRACK TO SFC LOW ON MONDAY (NORTHERN LK
SUPERIOR MONDAY MORNING INSTEAD OF OVR SOUTHERN LK MICHIGAN). SO AS
MUCH AS WOULD HAVE LIKED TO HAVE THE HIGHER RESOLUTION NAM THERMAL
PROFILES TO USE IN THIS FCST...HAVE TO DISCOUNT THE NAM AT THIS
TIME. SHOULD NOTE THAT IT APPEARS THE 12Z NAM IS TRENDING TOWARD
MAJORITY OF OTHER MODELS...SO MAYBE IT WILL BE MORE USEFUL IN 24
HRS. MOVING ON THAT LEAVES THE ECMWF AND UKMET IDEA (WHICH HAVE BEEN
CONSISTENT AND PREFERRED WITH THIS SYSTEM FOR SOME TIME NOW) AS WELL
AS THE GFS WHICH BEGAN TRENDING TOWARD ECMWF/UKMET IDEA WITH THE 18Z
RUN ON 1/20. CANADIAN ALSO PRETTY MUCH IN LINE NOW AS WELL...THOUGH
RUN-TO-RUN CONSISTENCY WITH SFC LOW TRACK ON MONDAY STILL NOT THE
GREATEST. SHOULD NOTE...12Z GFS DID TREND A BIT TOWARD NAM IDEA AND
WAS NOT PREFERRED BY HPC. 12Z ECMWF/CANADIAN/UKMET REMAIN CONSISTENT
WITH PREVIOUS MODEL RUNS.
APPEARS THAT THOUGH THERE IS SOME INTERACTION WITH NORTHERN STREAM
LATER MONDAY AND MONDAY NIGHT...THIS SYSTEM WILL BE MAINLY SOUTHERN
STREAM ORIGIN. WITH THAT WILL COME GOOD TAP OF GULF MOISTURE WITH
PWATS OVR 250 PCT OF NORMAL BY 12Z MONDAY OVR MOST OF THE CWA.
POSITION OF H85 TROUGH AND SRLY H85 WINDS PUT STRONGEST H85 THETA-E
ADVECTION OVER EAST HALF OF CWA BTWN 09Z-15Z MONDAY. HEAVIEST QPF IS
FCST OVR CNTRL AND EAST CWA. RUN TOTAL QPF THROUGH 00Z TUESDAY (WHEN
DEEPER MOISTURE/HIGHER PWATS SHIFT TO THE NORTHEAST INTO
ONTARIO/QUEBEC) RANGE FROM 0.50-0.90 OF AN INCH WITH CANADIAN UP OVR
1 INCH...HEAVIEST CNTRL CWA DUE TO DEFORMATION ON BACK EDGE OF
H85-H7 LOWS AND IT IS ALSO WHERE THERE IS A HINT OF A TROWAL HANGING
BACK OVR THE AREA AS H85-H7 LOWS MAINTAIN STEADY STRENGTH WHILE
HEADING INTO ONTARIO.
LOW-LEVEL THERMAL PROFILES WILL BE CRITICAL COMPONENT WITH THIS
SYSTEM...ESPECIALLY THROUGH NOON ON MONDAY. BASED ON 0C H85
LINE...RAIN WILL BE MAIN PTYPE EAST OF MARQUETTE AND DICKINSON
COUNTIES...WITH SNOW TO THE WEST. TROUBLE IS THAT SFC-BLYR TEMPS
WILL BE VERY CLOSE TO FREEZING AS THE RAIN ARRIVES FM THE SOUTH LATE
SUNDAY NIGHT. COULD EVEN BE SLEET OR SNOW RIGHT AT THE ONSET OF
PRECIPITATION SUNDAY NIGHT AS WELL AS COLD AIR ALOFT SLOWLY EVADES.
BELIEVE FREEZING RAIN WILL BE BIGGEST CONCERN TOWARD DAYBREAK MONDAY
AND THROUGH ABOUT MID MORNING...THEN BLYR WARMING IN THE EAST SHOULD
CHANGE PTYPE TO JUST RAIN. DUE TO COLD SPELL LATELY...WARMING OF
GROUND SFC TEMPS WILL LAG THE AIR TEMPS...SO MAY BE SITUATION WHERE
TEMPS AT OBSERVATION PLATFORMS (ASOS/AWOS/RAWS) ARE IN THE MID 30S
BUT THERE IS STILL ICING OCCURRING ON COLDER UNTREATED SURFACES.
UNFORTUNATELY...THESE THERMAL QUESTIONS ABOUND THE FIRST PART OF
MONDAY WHEN BULK OF HEAVIER QPF IS FCST WITH WARM AIR ADVECTION
ALOFT AT ITS PEAK. DO THINK THERE IS A GREATER THAN 50 PCT CHANCE
OF SIGNIFICANT ICING LATE SUNDAY NIGHT AND MONDAY MORNING...
ESPECIALLY AWAY FM THE IMMEDIATE SHORELINES OF LK SUPERIOR AND LK
MICHIGAN.
EVENTUALLY...BLYR WARMING WILL RESULT IN MOSTLY RAIN BY LATE MORNING
EAST OF MUNISING TO MENOMINEE AS SFC LOW IS FCST TO DEEPEN AND MOVE
FM SOUTHEAST WI TO SCNTRL UPR MI AND EVENTUALLY OUT OVR SOUTHEAST LK
SUPERIOR BY MONDAY EVENING. SITUATION COULD BECOME VERY FAVORABLE
FOR HEAVIER SNOW OVR CNTRL CWA THOUGH...MAINLY OVR HIGHER TERRAIN
JUST WEST OF MARQUETTE INTO PORTIONS OF KEWEENAW AND AS FAR SOUTH
AS WI BORDER...EVENTUALLY SPREADING INTO ALGER AND DELTA COUNTIES BY
LATE AFTN. PRIMARYDRIVER FOR POTENTIALLY HEAVIER SNOW IS VERY TIGHT
H85 TEMPERATURE GRADIENT OVR CNTRL CWA/INCREASING DEFORMATION ON
WEST SIDE OF CLOSED OFF H85-H7 LOWS AND LINGERING TROWAL REGION MOST
NOTED 950-750MB. NORTHERN STREAM WAVE DIGGING INTO THE SOUTHERN STREAM
SYSTEM WILL ALSO LEAD TO STRONGER DEFORMATION PRECIP REGION.
HEADLINES...GIVEN THIS SYSTEM WILL BE AFFECTING THE AREA ON A MONDAY
WHEN THERE IS LOT OF TRAVEL WITH WORK/SCHOOL/ETC AND SINCE THIS
SYSTEM HAS POTENTIAL TO BE HIGHER IMPACT DUE TO AMOUNT OF MOISTURE
AVAILABLE...THINK GOING WITH A WATCH RIGHT NOW IS A GOOD IDEA. MAIN
ISSUE FOR ALGER AND DELTA COUNTY EASTWARD IS THE INITIAL ICE THREAT
LATER SUNDAY NIGHT INTO MONDAY MORNING. A MIXED BAG OF ICE AND SNOW
AND SOME SLEET IS MAIN ISSUE FOR AREAS OVR CNTRL UPR MI...BASICALLY
MARQUETTE AND DICKINSON/MENOMINEE COUNTIES. FARTHER WEST...IT WOULD
BE GENERALLY A SNOW EVENT. ONLY PLACE WHERE WINTER STORM WATCH WILL
NOT BE ISSUED IS FAR WEST CWA AS MODELS ARE VERY INSISTENT IN SHOWING
THEM BEING MISSED BY INITIAL WARM AIR ADVECTION PRECIPITATION LATE
SUNDAY NIGHT/MONDAY MORNING AND GENERALLY KEEPING THE PRIMARY
DEFORMATION AXIS TO THE EAST OF THOSE AREAS ON MONDAY AFTN/MONDAY
EVENING. WATCHES WILL RUN FM LATE SUNDAY NIGHT THROUGH MONDAY
EVENING FOR MARQUETTE AND DICKINSON COUNTIES WESTWARD BUT WILL KEEP
ENDING TIME SHORTER FARTHER EAST AS MOST PTYPE BY AFTN WILL BE
RAIN/DRIZZLE AND SNOW SHOULD NOT BE SIGNIFICANT...ESPECIALLY IN FAR
EAST TOWARD KERY.
LK EFFECT...POSSIBLY ENHANCED BY DEPARTING SYSTEM WILL TARGET NW
FLOW AREAS LATER MONDAY NIGHT INTO TUESDAY MORNING. GUSTY NW WINDS
WILL LEAD TO BLSN ISSUES AS WELL. WILL GO AHEAD AND RUN WATCHES
THROUGH 12Z WHERE LK EFFECT/BLSN WILL BE HAZARD LATER MONDAY NIGHT.
COORD WITH DLH...GRB...APX AND ALSO HPC ON THIS SYSTEM.
FOR THE EXTENDED /TUESDAY NIGHT THROUGH SATURDAY/...
A SLIGHTLY AMPLIFIED FLOW WITH A BROAD EASTERLY TROUGH AND WEAK
WESTERN RIDGE WILL DEVELOP AND LEAD TO A GENERALLY SUSTAINED WNW/NW
FLOW OVER THE UPPER GREAT LAKES THROUGH MOST OF THE PERIOD. A SERIES
OF SHORTWAVE TROUGHS AND RIDGES WILL PROGRESS ALONG THE WESTERN SIDE
OF THE EASTERN TROUGH AND ALLOW FOR PERSISTENT BUT SMALL PRECIP
CHANCES. HOWEVER...THERE IS DISAGREEMENT IN THE GUIDANCE WITH THE
TIMING OF EACH OF THESE PULSES.
CAA ON THE BACKSIDE OF MONDAYS DEPARTING LOW WILL CEASE TUESDAY
EVENING AS SFC/850MB WINDS BACK TO THE WEST WITH THE PASSAGE OF A
SHARP MID LEVEL RIDGE. SOME LES WILL REMAIN EARLY IN THE EVENING
ACROSS EASTERN PARTS OF THE CWA...AND THROUGHOUT THE EVENING IN THE
KEWEENAW PENINSULA. THERE WILL BE A BRIEF BREAK AFTER THE RIDGE
PASSES BEFORE THE FIRST IMPULSE DIGS SOUTHEAST OUT OF SOUTH CENTRAL
CANADA WEDNESDAY NIGHT THROUGH THURSDAY. THE GFS AND ECMWF WERE IN
DECENT AGREEMENT WITH THE STRENGTH OF THIS WAVE...BUT THE 12Z GFS
HAS TRENDED STRONGER. AT THE SAME TIME...THE GEM HAS NEARLY ZONAL
FLOW WEDNESDAY BEFORE DEVELOPING A WEAK SHORTWAVE THURSDAY
AFTERNOON. ALL THREE MODELS DO KEEPS MUCH OF THE PRECIPITATION OVER
LAKE SUPERIOR AND THE EASTERN HALF OF THE CWA...SO WILL KEEP CHANCES
IN THE FORECAST FOR WEDNESDAY NIGHT. ONLY A VERY SHORT PERIOD OF
LES...6 TO 12 HOURS...IS POSSIBLE FOR WNW FAVORED WIND BELTS
THURSDAY AS BOTH THE GFS AND ECMWF ARE VERY AGGRESSIVE IN BRINGING
DRY AIR AND A SHARP LOW LEVEL RIDGE ACROSS LAKE SUPERIOR THURSDAY
EVENING. EVEN MORE...RAPIDLY LOWERING INVERSION HEIGHTS TO BELOW
3KFT AND TEMPERATURES BELOW THE INVERSION GENERALLY >-12C WILL LOWER
GOOD LES CHANCES.
MORE DISAGREEMENT RESIDES WITH THE NEXT WAVE PROGGED TO PASS TO THE
NORTH OF THE CWA ON FRIDAY. THE 00Z ECMWF SHOWS AN OPEN WAVE AT
500MB OVER WESTERN ONTARIO 18Z FRIDAY...WHEREAS THE GFS HAS A CLOSED
500MB LOW OVER NORTHERN MANITOBA. THE GFS HAS BEEN RATHER CONSISTENT
WITH THIS FEATURE FOR THE LAST DAY WHILE THE ECMWF PULLED THE TROUGH
FURTHER SOUTH. ATTM...THE GFS SEEMS TO BE THE BETTER CHOICE...THOUGH
BOTH HAVE A COLD FRONT MOVING ACROSS CWA DURING THE DAY FRIDAY. AS
THIS OCCURS...THE SURFACE LOW WILL BE TRACKING JUST AHEAD OF THE
MIDLEVEL LOW ALONG THE SOUTHWEST SHORE OF HUDSON BAY. NEAR THE CWA
THE FORCING WILL BE PURELY FRONTAL...WITH THE STRONGEST BAND OF
FRONTOGENESIS NORTH OF LAKE SUPERIOR BETWEEN 500 AND 700MB.
THERE IS ALSO CONCERN ABOUT THE LACK OF MOISTURE WITH THIS FRONTAL
PASSAGE AS AIR AHEAD OF THE FRONT WILL BE PULLED FROM DRY
CONTINENTAL AIR IN THE LEE OF THE NORTHERN ROCKIES.
AIR BEHIND THE COLD FRONT ON FRIDAY WILL BE OF WARMER PACIFIC
ORIGIN...WITH INVERSION HEIGHTS DROPPING INTO THE EVENING. NW FLOW
LES WILL STILL BE A POSSIBILITY...BUT WILL BE GREATLY SUPPRESSED BY
LOW INVERSIONS AND HIGH 850/925MB TEMPERATURES. AIR OF MORE ARCTIC
ORIGIN COMES IN BEHIND A SECONDARY COLD FRONT ON SATURDAY
MORNING...THOUGH MOISTURE IS LACKING WITH THIS FRONT AS WELL. WILL
STAY GENERALLY DRY IN TERMS ON POTENTIAL FRONTAL AND LES PRECIP
EXCEPT ALONG THE KEWEENAW PENINSULA.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
ALTHOUGH SOME LO CLDS/MVFR CIGS MAY LINGER AT CMX EARLY IN THIS TAF
PERIOD...EXPECT THIS LO CLD TO LIFT AWAY TO THE N SOON AFTER TAF
ISSUANCE WITH STRENGTHENING S WIND. OTRW...VFR CONDITIONS WILL
PREVAIL INTO TNGT. THEN STEADY S WIND WILL ADVECT ABUNDANT LLVL
MSTR/LO CLD NOW SHOWING UP WELL TO THE S INTO UPR MI LATE TNGT THRU
SUN MRNG. EXPECT DOWNSLOPING WIND COMPONENT AT IWD/CMX TO BREAK UP
THE BULK OF THIS CLD IN THOSE LOCATIONS...WITH BETTER CHC OF MVFR
CIG IMPACTING THE SAW LOCATION WITH MORE OF AN UPSLOPE WIND
COMPONENT THERE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
OPTED TO UPGRADE GALE WATCH TO A WARNING OVER THE E PART OF LK SUP
FOR LATE TONIGHT THRU SUN WITH STRENGTHENING SLY FLOW UNDER
SHARPENING PRES GRADIENT BETWEEN DEPARTING HI PRES RIDGE TO THE E
AND DEVELOPING LO IN THE PLAINS. A NNW GALE IS LOOKING MORE LIKELY
FOR MON NIGHT/TUE AS DEEPENING LO PRES TRACKING JUST TO THE E MOVES
INTO SE CANADA. THE WINDS WILL DIMINISH BY TUE NIGHT WITH APPROACH
OF HI PRES RIDGE. ALTHOUGH ANOTHER LO PRES MAY IMPACT THE LAKE ON
THU...NO GALES APPEAR LIKELY ATTM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
FOR MIZ001-003-004.
WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT FOR MIZ005-006-011>014-085.
WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY
AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 7 PM EST SUNDAY FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
EXTENDED...TK
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
255 PM CST SAT JAN 21 2012
.DISCUSSION...
Pesky strato-cu layer finally beginning to erode from the south and
west as warmer air aloft and increased mixing eat away at the
shallow saturated zone around H9. Only RUC H9 condensation pressure
deficit forecasts have accurately depicted this cloud deck today,
and show the layer finally giving way just before sunset. Still
expecting temperatures to go nowhere this evening, then actually
begin a slow climb after midnight with waa and mixing. New stratus
layer currently over NE TX/SE OK will advect north with the leading
edge of the moisture tongue, and could potentially see some fog and
drizzle in this band. However, believe forecast soundings and
numerical guidance are underestimating soil temperatures and tend to
favor more light fog/haze with dew deposition versus reduced
visibilities/drizzle in a well mixed boundary layer. Have introduced
a patchy drizzle mention later in the morning as soundings begin to
look a bit more favorable (in addition to model qpf output), but not
expecting a persistent or widespread drizzle.
Rather potent shortwave now crossing the Sierra Nevada will eject
into the central plains Sunday afternoon allowing a nice surge of
warm, moist air throughout the forecast area. Surprisingly with
better raob sampling at 12Z, there are still discrepancies among
operational models, though the general trend is for a weaker system
ejecting and lifting out further to the northwest (roughly a
KMHK-KDSM-KMSN line). Still prefer a somewhat slower and further
south timing and position per consistent ECMWF solutions given the
jet streak remaining on the south and west side of the trough base.
This should keep the majority, if not all of the cwa in the warm
sector through most of the day, and have correspondingly went
towards the warmer guidance numbers for high temps. Some locations
could spike even warmer if more than a few peaks of sun are
realized, and would not be surprised if some locations pushed above
60F.
For the most part, warm sector rainfall and convection should remain
relegated to the middle and lower Mississippi River valley Sunday
evening, with weak frontogenesis/deformation trailing through
central Kansas. Much of the local area will be dealing with the
dryslot and downslope westerly component Sunday evening, only seeing
meager wrap around moisture and precipitation potential with the
wave lifting to the northwest. Have generally cut pops and qpf
amounts given model trends, and would not expect much more than a
dusting or few tenths of rain/snow mix over northwest and north
central Missouri by Monday morning.
Virtually no cold air exists behind this system for early next week,
such that post frontal lows Monday morning will remain above average
in a well mixed boundary layer. Dry weather can be expect Monday
with the only real concern revolving around the potential of an
elevated fire danger given dry westerly downslope sfc wind, lowering
relative humidity values, and warmer than average temperatures.
21
Medium range (Tuesday through Saturday)...
For the later half of the forecast, medium range models continue to
show a fair amount of agreement on the large scale features for next
week`s forecast. A quasi-zonal flow regime is advertised to persist
across the continent as the flow across the eastern Pacific remains
rather flat. This will continue to allow fast moving shortwaves to
jet across the nation, with a few expected to periodically
cutting-off over the Desert Southwest. This would indicate that
temperatures should remain above average over the last half of the
forecast as the majority of the cold air remains sequestered to our
north, allowing afternoon highs to range from the 40s into the 50s,
with overnight lows in the mid 20s to mid 30s.
Looking closer at the forecast specifics, mid-range models of late
have begun to settle on a solution which cuts-off a low across the
Desert Southwest early in the coming work week as energy gets dumped
from the Pacific jet into a 500mb weakness noted across northern
Mexico. This is counter to other recent solutions which advertised a
more progressive track for the shortwave energy, ultimately hinting
at precipitation chances across Kansas and Missouri in the Tuesday
to Wednesday time frame. However, with the growing consensus that
the cutoff low will develop and eject through the southern Plains,
the needed moisture and lift for any precipitation looks like it
will pass to our south, thus have only kept a silent 20% POP in for
Tuesday night.
Cutter
&&
.AVIATION...
Very low confidence throughout the 18Z taf period as models are
still struggling with mvfr cigs blanketing the area this morning;
and have significant disagreement regarding return moisture surging
north tomorrow morning. Have utilized a persistence forecast along
with RUC 925 mb condensation pressure deficits in determining the
longevity and areal extent of mvfr cigs this afternoon. Feel erosion
will take longer than models indicate, but then become rapid as
mixing within the cloud layer increases towards sunset.
Have introduced a LLWS mention overnight as a sly LLJ strengthens
with pressure falls to the west. Moisture should begin to surge
north over cooler ground leading to lower cigs overspreading the
terminals. Timing remains very uncertain and have trended towards a
period after forecast soundings would suggest, but before most
numerical guidance. Kept heights in the lower mvfr category, but
could easily see heights come in the ifr or lifr category based on
some forecast sounding data.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1145 AM CST SAT JAN 21 2012
...UPDATED AVIATION...
.DISCUSSION...
Early this morning, moisture trapped under a steep low level
inversion in the form of stratus continues to advect southeast into
the CWA. This stratus may prevent temperatures from falling into the
single digits, but also poses a significant problem for high
temperatures. The main forecast concerns are focused on precipitation
chances on Sunday and Sunday night, and on temperatures throughout
the upcoming week.
For today: weak shortwave energy moving over Missouri this morning
will quickly shift into the Ohio River valley today. Stratus is
expected to hang around for a good portion of the day as low-level
ridging axis does not slide through the area until early afternoon.
Temperatures will remain in the 20s over northern Missouri with lower
30s possible in central Missouri and eastern Kansas.
Tonight-Sunday: Our attention turns to a strong but very progressive
upper trough moving over the Pacific coastline this morning. This
upper trough is expected to pass through the region Sunday and end up
in the Great Lakes by Monday. Ahead of the wave, northward theta-e
advection will commence in earnest this evening with condensation
pressure deficit plots indicating rapid stratus development. This
stratus combined with increasing low-level warm advection should lead
to a reversal of falling overnight temperatures with readings
climbing after midnight. By 18z Sunday, surface troughing is expected
to remain just west of the CWA. With pronounced meridional flow and
an increasing surface pressure gradient, a very tricky temperature
forecast will develop. Should stratus not be as thick as anticipated,
or low- level cold advection develop later than currently forecast,
temperatures could shoot well into 50s over a large chunk of the
forecast area. Regarding the chance for precipitation, given the
progressive nature of this wave and lack of downstream blocking there
will not be enough time for deep moisture from the GOM to reach the
area, with low level trajectories pushing higher quality moisture
towards the lower Mississippi river valley. Thus, soundings reveal
only minor saturation in the lowest levels which given isentropic
lift and dynamic forcing aloft may be enough to produce light
showers ahead of the surface front Sunday afternoon. On the backside
of the upper wave there may be enough moisture to produce a fast
moving band of mixed precipitation mainly over the northwestern and
western grids before this system rotates into the Great Lakes Monday
morning.
Monday-Friday: Behind this system, little change in the overall
weather pattern is anticipated with very progressive quasi-zonal flow
continuing through the week. There remains little signal of any
organized precipitation events in the local area. Temperatures will
continue the trend of running above normal through the week.
Dux
&&
.AVIATION...
Very low confidence throughout the 18Z taf period as models are
still struggling with mvfr cigs blanketing the area this morning;
and have significant disagreement regarding return moisture surging
north tomorrow morning. Have utilized a persistence forecast along
with RUC 925 mb condensation pressure deficits in determining the
longevity and areal extent of mvfr cigs this afternoon. Feel erosion
will take longer than models indicate, but then become rapid as
mixing within the cloud layer increases towards sunset.
Have introduced a LLWS mention overnight as a sly LLJ strengthens
with pressure falls to the west. Moisture should begin to surge
north over cooler ground leading to lower cigs overspreading the
terminals. Timing remains very uncertain and have trended towards a
period after forecast soundings would suggest, but before most
numerical guidance. Kept heights in the lower mvfr category, but
could easily see heights come in the ifr or lifr category based on
some forecast sounding data.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
249 PM CST SAT JAN 21 2012
.DISCUSSION...
THE RUC CONTINUES TO INDICATE WIND ADVISORY CONDITIONS DEVELOPING
ACROSS NCNTL NEB THIS AFTERNOON AS LOW PRESSURE DEEPENS ACROSS THE
HIGH PLAINS. WIND SPEEDS SHOULD PEAK DURING THE LATE AFTERNOON AND
THEN FALL OFF WITH THE LOSS OF DAYTIME HEATING.
SOUTH WINDS CONTINUE OVERNIGHT AS A STRONG PACIFIC COLD FRONT
APPROACHES THE PLAINS. THIS FRONT WILL SWEEP THROUGH THE FCST AREA
SUNDAY MORNING AND LOW PRESSURE WILL CONSOLIDATE ACROSS THE
MIDWEST. STRONG NORTHWEST WINDS WILL DEVELOP BEHIND THE SFC LOW
ASSOCIATED WITH PACIFIC HIGH PRESSURE. A BLEND OF MAV AND MET
GUIDANCE PRODUCED HIGH END WIND ADVISORY CONDITIONS. DEUEL COUNTY
COULD PERHAPS REACH HIGH WIND CATEGORY BUT THAT IS LIKELY A RESULT
OF WEIGHTING FACTORS ASSOCIATED WITH THE DATA FROM KSNY. THE NAM
INDICATED GUSTS TO 55 MPH BUT ONLY ACROSS A SMALL PART OF CHERRY
COUNTY. WINDS ARE EXPECTED TO STAY UP EAST OF HIGHWAY 83 SUNDAY
EVENING FOR A FEW HOURS AS WRAP AROUND STRATUS PRODUCES A SHALLOW
MIXED LAYER. WIND SPEEDS SHOULD DECLINE BETWEEN 03Z AND 06Z AS THE
SFC LOW WILL PRESUMABLY BE FAR ENOUGH EAST FOR THE WINDS TO RELAX.
ELSEWHERE WINDS SHOULD DROP OFF QUICKLY AS A CLEARING LINE MOVES
EAST TO NEAR HIGHWAY 83 BY 00Z MONDAY.
A BLEND OF ECMWF...GEM REGIONAL...NAM AND GFS WAS USED FOR QPF
AMOUNTS WHICH ARE GENERALLY 1/10 OF INCH OR LESS. NOTE THE QPF IS
POST FRONTAL AND THE PTYPE IS SNOW. WITH THE H700MB LOW TRACKING
THROUGH THE NRN PLAINS...SNOW SHOWERS WOULD APPEAR TO BE THE
DOMINANT STORM MODE BUT WE MAY BE DEALING WITH A MIXED MODE AT TIMES.
THE NAM AND GFS ALSO KEEP THE FCST AREA MOSTLY DRY SO POPS ARE CHC
CATEGORY. HPC FAVORED THE GEM MODEL AND THE UKMET. THE ECMWF
APPEARED TO BE THE WETTER SOLN. THE GEM REGIONAL DEVELOPS A WEDGE
OF WARP AROUND QPF ACROSS THE ERN ZONES AMOUNTING TO 1/3 OF AN
INCH. GIVEN THE STRONG WINDS...SIGNIFICANT BLOWING SNOW WOULD
DEVELOP IF THAT WERE TO VERIFY.
HIGH PRESSURE SETTLES OVER THE FCST AREA MONDAY MORNING THROUGH TUESDAY.
A SPLIT IN THE WESTERLIES DEVELOPS SENDING A LARGE UPPER LEVEL CUTOFF
LOW THROUGH THE SRN PLAINS TUESDAY THROUGH FRIDAY. THIS SYSTEM
WILL HAVE LITTLE OR NO EFFECT ON THE SENSIBLE WEATHER ACROSS THE FCST
AREA EXCEPT TO HOLD PACIFIC HIGH PRESSURE IN PLACE. DEEP LOW PRESSURE
CIRCULATING THROUGH CNTL AND SRN CANADA WILL ALSO DRAW PACIFIC
HIGH PRESSURE THROUGH THE CNTL PLAINS WEDNESDAY AND THURSDAY
BEFORE ANOTHER STRONG PACIFIC COLD FRONT DROPS THROUGH THURSDAY
NIGHT OR FRIDAY.
THE FCST IS DRY MONDAY THROUGH SUNDAY. THE GFS IS AMPLIFYING A
DISTURBANCE THRU THE FCST AREA SATURDAY BUT IT APPEARS TO BE TOO
FAST. THE ECMWF HOLDS THAT FEATURE OFFSHORE IN THE PACIFIC.
&&
.AVIATION...
WINDS WILL DECREASE TONIGHT AS THE PRESSURE GRADIENT EASES. THEN...A
COLD FRONT WILL MOVE EAST ACROSS NEBRASKA TONIGHT...BRINGING A WIND
SHIFT TO THE NORTHWEST BY 12Z AT BOTH KVTN AND KLBF. THE WIND SPEEDS
WILL INCREASE THROUGH THE DAY...WITH GUSTS UPWARDS OF 35 TO 40KTS BY
LATE MORNING AS COLD AIR ADVECTION AIDES IN STRONGER WINDS ALOFT
BEING ABLE TO BE MIXED TO THE SURFACE. IN ADDITION...THERE DOES LOOK
TO BE SOME PRECIPITATION BEHIND THE FRONT...WHICH MAY MOVE INTO THE
KVTN TERMINAL IN THE MORNING HOURS. HAVE TRENDED THE FORECAST TO
INCLUDE A CEILING DROPPING TO MVFR...ALONG WITH DECREASED
VISIBILITIES DUE TO -SN IN THE LATE MORNING. TIMING MAY NEED TO BE
ADJUSTED IN FOLLOWING FORECASTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FROM 6 AM CST
/5 AM MST/ TO 6 PM CST /5 PM MST/ SUNDAY FOR
NEZ004-005-022>025-035>037-056>059-069>071-094.
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
NEZ005>010-094.
WIND ADVISORY FROM 9 AM TO 9 PM CST SUNDAY FOR NEZ006>010-
026>029-038.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1138 AM CST SAT JAN 21 2012
.AVIATION... /FOR THE 18Z TAF ISSUANCE/
THE NEXT 24 HOURS WILL BE BUSY FOR AVIATION CONCERNS. STRONG
SOUTHERLY WINDS WILL BE OBSERVED THROUGH THE REMAINDER OF THE
AFTERNOON AS A TIGHT PRESSURE GRADIENT HAS SET UP ACROSS THE AREA
AHEAD OF A STATIONARY FRONT OVER THE EASTERN PARTS OF WYOMING AND
COLORADO. WINDS AT 850MB AT THE MRRN1 PROFILER IN NORTHWEST
CHERRY COUNTY WERE 50KTS AT 15Z...WITH LESSER SPEEDS GOING SOUTH.
ASSUMING THERE WILL BE SOME MIXING THIS AFTERNOON...PLAN ON
SUSTAINED WINDS RANGING FROM AROUND 20 KT IN SOUTHWEST NEBRASKA TO
28KTS IN NORTHERN NEBRASKA...WITH GUSTS OF 25 TO 35KTS.
THE FRONT TO THE WEST WILL MOVE EAST ACROSS NEBRASKA
TONIGHT...ALLEVIATING THE PRESSURE GRADIENT AND ALLOWING WINDS TO
DECREASE A BIT OVERNIGHT. BEHIND THE FRONT...WINDS WILL SHIFT TO
THE NORTHWEST AND INCREASE. THE WIND SHIFT SHOULD REACH BOTH KVTN
AND KLBF BY 12Z...WITH AN INCREASING TREND THROUGH THE MORNING. BY
LATE MORNING COULD SEE GUSTS UPWARDS OF 35 TO 40KTS AS COLD AIR
ADVECTION AIDES IN STRONGER WINDS ALOFT BEING ABLE TO BE MIXED TO
THE SURFACE. IN ADDITION...THERE DOES LOOK TO BE SOME
PRECIPITATION BEHIND THE FRONT...WHICH MAY MOVE INTO THE KVTN
TERMINAL IN THE MORNING HOURS. HAVE TRENDED THE FORECAST TO
INCLUDE A CEILING DROPPING TO IFR...ALONG WITH DECREASED
VISIBILITIES WITH -SN IN THE LATTER PARTS OF THE FORECAST PERIOD.
TIMING MAY NEED TO BE ADJUSTED IN FOLLOWING FORECASTS.
&&
.PREV DISCUSSION... /ISSUED 1043 AM CST SAT JAN 21 2012/
UPDATE...
SFC WINDS ARE ON THE WAY UP THIS MORNING WITH LOW PRESSURE DEEPENING
ACROSS THE HIGH PLAINS. MERRIMAN PROFILER SHOWING 50KT AT THE
LOWEST GATE. THE RUC SHOWS THIS BANK OF STRONG WINDS SHIFTING EAST
AND MIXING DOWN THIS AFTERNOON SO A WIND ADVISORY IS IN PLACE FROM
WRN CHERRY EAST. KICR GUSTED TO 40KT AT 1546UTC AND THIS APPEARS
TO BE A SIGN OF THINGS TO COME.
PREV DISCUSSION... /ISSUED 400 AM CST SAT JAN 21 2012/
SYNOPSIS...
ARCTIC 1026 MB HIGH PRESSURE CENTERED OVER MINNESOTA THIS
MORNING...AND SLIDING SOUTHEAST. WINDS HAVE BECOME SOUTH TO
SOUTHWEST OVER THE CWA...WITH TEMPS IN THE LOWER TEENS. SATELLITE
SHOWING SOME LOW STRATUS OVER PARTS OF CENTRAL AND EASTERN
NEBRASKA. WATER VAPOR IMAGERY SHOW SPLIT FLOW CONTINUING WITH
WESTERN CONUS SYSTEM SPLITTING.
DISCUSSION...
WITH THE HIGH FINALLY MOVING TO THE SOUTHEAST...AND RETURN
SOUTHERLY FLOW...SHOULD BE ABLE TO WARM MOST OF THE CWA UP TODAY.
GUIDANCE IN GOOD AGREEMENT WITH 40S OVER WESTERN ZONES...30S
EAST. HOWEVER WITH THE WARMER TEMPS WILL COME GUSTY WINDS. TIGHT
PRESSURE GRADIENT...WITH 3 HR PRESSURE FALLS AROUND 6 MB. MOS AND
RAW MODEL DATA KEEPS WINDS BELOW GUIDANCE...AND FORECAST
FOLLOWS...HOWEVER WILL NEED TO MONITOR. HIGHEST WINDS AT 850 MB
APPROACH 60 KTS OVER NORTH CENTRAL...HOWEVER DO NOT EXPECT TO
FULL MIX WHERE THE STRONGEST WINDS ALOFT ARE.
TONIGHT THE NEXT LOW PRESSURE SYSTEM WILL CROSS THE NORTHERN
ROCKIES...AND PUSH ONTO THE PLAINS. LOWER LEVELS ON THE DRY SIDE
INITIALLY AND WILL NEED TO SATURATE TOP DOWN. THIS WILL LIKELY
LIMIT THE AMOUNT OF QPF TO REACH THE GROUND. MIXING WILL KEEP
TEMPS UP AND HAVE KEEP A MIX OF PRECIP BEFORE 06Z. AFTER 00Z COLD
FRONT SHOULD BE CROSS THE AREA...WITH A CHANGE OVER TO SNOW. LIFT
IS FOCUSED MORE TO THE NORTH...WITH ONLY VERY LIGHT ACCUMULATIONS
EXPECTED...AT BEST. WITH THE CLOUDS EXPECT LOWS TO REMAIN
MILD...IN THE 20S.
SUNDAY COLD FRONT SHOULD PUSH ACROSS THE AREA EARLY. STRONG NW
WINDS DEVELOP BEHIND THE FRONT...ALONG WITH THE CONTINUE SLIGHT
CHANCE FOR PRECIP. WET BULB EFFECT...PER MODEL SOUNDING
ANALYSIS...SHOULD RESULT IN ANY PRECIP IN THE FORM AS
SNOW...HOWEVER WITH TEMPS WELL INTO THE 30S...POSSIBLY 40 FOR
SUNDAY...COULD BRIEFLY SEE A MIX. MORE OF A CONCERN IS THE STRONG
WINDS. WIND ADVISORY IS PROBABLE...HOWEVER WITH THE CHANCE FOR
PRECIP...WILL HOLD OFF ON ANY HEADLINE AS MAY NEED TO INCORPORATE
LIGHT SNOW INTO THE HEADLINE.
ACTIVE PATTERN FOR NEXT WEEK...HOWEVER LIMITED MOISTURE TO WORK
WITH OVER THE CWA. SEVERAL WAVES TO PUSH ACROSS THE PLAINS...WITH
A STRONG WAVE TO PUSH ACROSS THE SOUTHERN PLAINS MONDAY NIGHT
THROUGH TUESDAY. ARCTIC AIR TO RETREAT NORTH WITH SEASONAL
CONDITIONS EXPECTED THROUGH MUCH OF THE WEEK. HIGHS IN THE 40S
WITH POSSIBLY 50S FOR THURSDAY AHEAD OF THE NEXT COLD FRONT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST /5
PM MST/ THIS EVENING FOR NEZ005>010-094.
&&
$$
SHORT TERM/EXTENDED...99
AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1043 AM CST SAT JAN 21 2012
.UPDATE...
SFC WINDS ARE ON THE WAY UP THIS MORNING WITH LOW PRESSURE DEEPENING
ACROSS THE HIGH PLAINS. MERRIMAN PROFILER SHOWING 50KT AT THE
LOWEST GATE. THE RUC SHOWS THIS BANK OF STRONG WINDS SHIFTING EAST
AND MIXING DOWN THIS AFTERNOON SO A WIND ADVISORY IS IN PLACE FROM
WRN CHERRY EAST. KICR GUSTED TO 40KT AT 1546UTC AND THIS APPEARS
TO BE A SIGN OF THINGS TO COME.
&&
.PREV DISCUSSION... /ISSUED 549 AM CST SAT JAN 21 2012/
AVIATION...
UNRESTRICTED CEILING AND VISIBILITY IS LIKELY IN CENTRAL AND
WESTERN NEBRASKA THROUGH THE NIGHT TONIGHT AND INTO EARLY SUNDAY.
AFTER ABOUT 15Z WIND OVER CENTRAL AND WESTERN NEBRASKA WILL
INCREASE AND BECOME 170-200 AND WINDY. WIND SPEEDS IN THE NORTH WILL
BE 18-21G27-31KT AND IN THE NORTH 16-18G24-28KT.
LOOKING BEYOND 12Z SUNDAY...WIND IS LIKELY TO BE EVEN STRONGER
AND OUT OF THE NORTH TO NORTHWEST OVER THE AREA LATE MORNING THROUGH
EARLY AFTERNOON.
PREV DISCUSSION... /ISSUED 400 AM CST SAT JAN 21 2012/
SYNOPSIS...
ARCTIC 1026 MB HIGH PRESSURE CENTERED OVER MINNESOTA THIS
MORNING...AND SLIDING SOUTHEAST. WINDS HAVE BECOME SOUTH TO
SOUTHWEST OVER THE CWA...WITH TEMPS IN THE LOWER TEENS. SATELLITE
SHOWING SOME LOW STRATUS OVER PARTS OF CENTRAL AND EASTERN
NEBRASKA. WATER VAPOR IMAGERY SHOW SPLIT FLOW CONTINUING WITH
WESTERN CONUS SYSTEM SPLITTING.
DISCUSSION...
WITH THE HIGH FINALLY MOVING TO THE SOUTHEAST...AND RETURN
SOUTHERLY FLOW...SHOULD BE ABLE TO WARM MOST OF THE CWA UP TODAY.
GUIDANCE IN GOOD AGREEMENT WITH 40S OVER WESTERN ZONES...30S
EAST. HOWEVER WITH THE WARMER TEMPS WILL COME GUSTY WINDS. TIGHT
PRESSURE GRADIENT...WITH 3 HR PRESSURE FALLS AROUND 6 MB. MOS AND
RAW MODEL DATA KEEPS WINDS BELOW GUIDANCE...AND FORECAST
FOLLOWS...HOWEVER WILL NEED TO MONITOR. HIGHEST WINDS AT 850 MB
APPROACH 60 KTS OVER NORTH CENTRAL...HOWEVER DO NOT EXPECT TO
FULL MIX WHERE THE STRONGEST WINDS ALOFT ARE.
TONIGHT THE NEXT LOW PRESSURE SYSTEM WILL CROSS THE NORTHERN
ROCKIES...AND PUSH ONTO THE PLAINS. LOWER LEVELS ON THE DRY SIDE
INITIALLY AND WILL NEED TO SATURATE TOP DOWN. THIS WILL LIKELY
LIMIT THE AMOUNT OF QPF TO REACH THE GROUND. MIXING WILL KEEP
TEMPS UP AND HAVE KEEP A MIX OF PRECIP BEFORE 06Z. AFTER 00Z COLD
FRONT SHOULD BE CROSS THE AREA...WITH A CHANGE OVER TO SNOW. LIFT
IS FOCUSED MORE TO THE NORTH...WITH ONLY VERY LIGHT ACCUMULATIONS
EXPECTED...AT BEST. WITH THE CLOUDS EXPECT LOWS TO REMAIN
MILD...IN THE 20S.
SUNDAY COLD FRONT SHOULD PUSH ACROSS THE AREA EARLY. STRONG NW
WINDS DEVELOP BEHIND THE FRONT...ALONG WITH THE CONTINUE SLIGHT
CHANCE FOR PRECIP. WET BULB EFFECT...PER MODEL SOUNDING
ANALYSIS...SHOULD RESULT IN ANY PRECIP IN THE FORM AS
SNOW...HOWEVER WITH TEMPS WELL INTO THE 30S...POSSIBLY 40 FOR
SUNDAY...COULD BRIEFLY SEE A MIX. MORE OF A CONCERN IS THE STRONG
WINDS. WIND ADVISORY IS PROBABLE...HOWEVER WITH THE CHANCE FOR
PRECIP...WILL HOLD OFF ON ANY HEADLINE AS MAY NEED TO INCORPORATE
LIGHT SNOW INTO THE HEADLINE.
ACTIVE PATTERN FOR NEXT WEEK...HOWEVER LIMITED MOISTURE TO WORK
WITH OVER THE CWA. SEVERAL WAVES TO PUSH ACROSS THE PLAINS...WITH
A STRONG WAVE TO PUSH ACROSS THE SOUTHERN PLAINS MONDAY NIGHT
THROUGH TUESDAY. ARCTIC AIR TO RETREAT NORTH WITH SEASONAL
CONDITIONS EXPECTED THROUGH MUCH OF THE WEEK. HIGHS IN THE 40S
WITH POSSIBLY 50S FOR THURSDAY AHEAD OF THE NEXT COLD FRONT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST
/5 PM MST/ THIS EVENING FOR NEZ005>010-094.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
310 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SATURDAY...POTENT SHORTWAVE CLEARLY EVIDENT ON WV
IMAGERY PUSHING ACROSS NORTH GEORGIA ATTM WILL PIVOT THROUGH THE
AREA TONIGHT. ADDITIONALLY...COLD FRONT MOVING EAST THROUGH UPSTATE
SC WILL BECOME MORE E-W ORIENTED AND DROP SOUTHWARD OVERNIGHT. THESE
TWO WILL WORK TOGETHER TO CONTINUE THUNDERSTORMS THROUGH TONIGHT.
LATEST REGIONAL MOSAIC SHOWS A LINE OF STRONGER THUNDERSTORMS FROM
APPROXIMATELY COLUMBIA, SC SOUTHWEST TO MACON, GA. THE STRONGEST
STORMS ARE COLLOCATED WITH ENHANCED LIFT FROM THE PUNCH OF THE S/W
TROUGH...AND EXPECT THE DEEPEST CONVECTION WILL PERSIST IN THIS
MANNER. ALTHOUGH THE SHORTWAVE IS PROGGED TO WEAKEN AS IT MOVES
NORTHEAST TONIGHT...IT APPEARS TO BE SLIGHTLY STRONGER THAN GUIDANCE
HAD SUGGESTED WHICH MAY PERMIT CONVECTION TO CONTINUE LONGER. LATEST
RUC AND HRRR ENSEMBLE REFLECTIVITY HAVE A GOOD HANDLE ON ONGOING
SITUATION...SO HAVE USED A BLEND OF THESE FOR TIMING OF CONVECTION.
VERY LITTLE INSTABILITY...LI`S GREATER THAN 0...AND WINDS ON THE LTX
VWP OF ONLY 30 KTS AT 2 KFT ALL PROMOTE THE CONTINUED IDEA OF ONLY
LIMITED SEVERE POTENTIAL DURING THE NEXT SEVERAL HOURS...EVEN THOUGH
THE SOUTHERN HALF OF THE CWA REMAINS IN A SLIGHT RISK.
STILL...FORECAST GUIDANCE DEVELOPS SOME 7 C/KM ML LAPSE RATES...LI`S
TO -2...AND 0-6 KM SHEAR SUPPORTIVE OF MULTICELL STRUCTURES. HAVE
KEPT SCT TSTMS IN WX GRIDS WITH CATEGORICAL POP FROM WEST TO EAST
THROUGH 10 PM. CANNOT RULE OUT ONE OR TWO WARNINGS TONIGHT...BUT
EXPECT PRIMARILY SUB-SEVERE WIND AND ISOLATED SMALL HAIL.
FROPA OCCURS OVERNIGHT...AND HAVE ADJUSTED MIN TEMPS DOWNWARD A FEW
DEGREES TO ACCOUNT FOR SLIGHTLY FASTER PROGRESSION. WINDS WILL TURN
TO THE NORTH AT LBT BY 10PM...WILMINGTON AROUND MIDNIGHT...AND
GEORGETOWN BY MORNING. VERY LITTLE DRYING BEHIND THE FRONT DUE TO
MOISTURE BECOMING TRAPPED BENEATH THE FRONTAL INVERSION...SO VERY
LIGHT RAIN SHOWERS AND DRIZZLE WILL PERSIST THROUGH MORNING. MINS
TONIGHT WILL RANGE FROM THE LOWER 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE FAR SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...COOL...CLOUDY AND MOIST DAY IN STORE FOR
SUNDAY AS A SHORT-LIVED COLD AIR DAMMING SITUATION SETS UP. STEADY
NE FLOW AT THE SURFACE AND EXTENSIVE CLOUD COVER WILL KEEP
AFTERNOON TEMPERATURES A DEGREE OR SO EITHER SIDE OF 50 MOST
LOCATIONS. AS IS TYPICAL FOR THIS TYPE OF PATTERN...EXPECT PATCHY
DRIZZLE OR LIGHT RAIN TO MAKE APPEARANCES AT TIMES...WITH MINIMAL
QPF DUE TO WEAK FORCING AND SHALLOW NATURE OF MOISTURE. THERE WILL
BE A LIMITED DIURNAL RANGE OF TEMPERATURES...WITH LOWS MAINLY IN
THE 40S OVERNIGHT.
WEDGE PATTERN WILL ERODE EARLY ON MONDAY AS A COLD FRONT AND
ASSOCIATED UPPER TROUGH APPROACH FROM THE WEST. FLOW WILL TURN TO
THE SOUTH AND THEN SW MONDAY AFTERNOON...ALLOWING FOR A BIG WARM
UP FROM THE PREVIOUS DAY. EXPECT HIGHS IN THE UPPER 60S TO AROUND
70...ABOUT 20 DEGREES HIGHER THAN ON SUNDAY. FRONT WILL MOVE
ACROSS THE EASTERN CAROLINAS MONDAY EVENING AND OVERNIGHT AND WILL
BE OFFSHORE BY AROUND DAYBREAK ON TUESDAY. MOISTURE WILL BE
LIMITED WITH THIS SYSTEM AND BEST UPPER SUPPORT WILL PASS WELL TO
THE NORTH...SO EXPECT ONLY ISOLATED TO SCATTERED CONVECTION TO
ACCOMPANY FROPA. NOT MUCH IN THE WAY OF COLD ADVECTION WITH THIS
FRONT...SO EXPECT LOWS WILL RANGE FROM THE MID 40S INLAND TO
AROUND 50 AT THE COAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 2:30 PM SATURDAY...MAIN FEATURE FOR THE EXTENDED CONTINUES
TO BE THE CUTOFF MEANDERING ABOUT THE SOUTHWEST AND WHEN IT GETS
KICKED OUT. THE LATEST OPERATIONAL RUN OF THE GFS HAS TRENDED MUCH
SLOWER WHILE PREVIOUS RUNS MAINTAINED MORE OF A ZONAL FLOW. HPC
CONTINUES TO FAVOR THE ECMWF SUITE OF PRODUCTS BASED ON MORE
CONSISTENCY. THESE ARE A BIT SLOWER WITH THE SYSTEM BUT OVERALL
ARE SIMILAR TO THIS TIME YESTERDAY. THE ONLY FORECAST CHANGES WITH
THIS PACKAGE WERE TO DELAY THE POPS SLIGHTLY MAINTAINING THE SAME
STRATEGY AS YESTERDAY WITH INCREASING VALUES FROM LATE THURSDAY
THROUGH THE NEW DAY SATURDAY. ONLY MINOR TWEAKS TO TEMPERATURES
WITH A SLIGHT INCREASE ACROSS THE BOARD TO MATCH HPC NUMBERS AND
ADJACENT OFFICES.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SATURDAY...WINDS AND SEAS ARE FINALLY INCREASING SO
SMALL CRAFT ADVISORY WILL CONTINUE THROUGH TONIGHT. SEAS HAVE ONLY
REACHED 6 FT AT FRYING PAN SHOALS SO FAR TODAY...MOSTLY BECAUSE THE
COLD SHELF WATERS HAVE INHIBITED THE STRONGEST WINDS FROM MIXING
DOWN TO THE SURFACE. WINDS HAVE BUMPED TO 20 KTS AT 41110 LAST HOUR
WITH SEAS APPROACHING 5 FT. SWAN AND WNAWAVE BOTH STILL EXPECTING
5-7 FT SEAS ACROSS AMZ250 AND AMZ252...WITH 4-6 FT IN THE SOUTHERN
WATERS. WITH WIND INCREASE...FEEL THIS IS PRUDENT...AND WILL KEEP
SCA AS IS. SMALL CRAFT CONDITIONS WILL IMPROVE RATHER QUICKLY
TONIGHT...BECOMING ONLY AROUND 10 KTS AND VEERING TO THE NORTH THEN
NORTHEAST BY SUNDAY MORNING. CONSEQUENTLY...SEAS FALL TO 3-4
FT...WITH A CONFUSED WAVE SPECTRUM DUE TO CHANGING WINDS.
SCATTERED SHOWERS AND THUNDERSTORMS WILL CROSS THE WATERS LATE
TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...NELY FLOW OVER THE WATERS ON SUNDAY WILL
TURN SWLY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST.
WINDS WILL RANGE FROM 15 TO 20 KTS EARLY ON SUNDAY BEFORE BECOMING
LIGHT AND VEERING TO THE SE OVERNIGHT WITH THE APPROACH OF THE
COLD FRONT. WINDS WILL PICK UP AGAIN MONDAY AFTERNOON BACK IN THE
15 TO 20 KT RANGE FROM THE SW. COLD FRONT MAY MOVE OFFSHORE BY
AROUND DAYBREAK ON TUESDAY. SEAS WILL RANGE FROM 3 TO 5 FT FOR
MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 2:30 PM SATURDAY...WESTERLY FLOW INITIALLY IN THE WAKE OF THE
COLD FRONT. A SECONDARY PUSH OCCURS LATE TUESDAY INTO WEDNESDAY
WHICH WILL TURN WINDS TO THE NORTHEAST. FINALLY RETURN FLOW SETS UP
THURSDAY AS A SYSTEM TAKES SHAPE WELL TO THE SOUTHWEST. OVERALL WIND
SPEEDS SHOULD REMAIN MODEST WITH THE POSSIBLE EXCEPTION OF LATE INT
HE PERIOD WHEN THE SOUTHWEST FLOW SURGES. SEAS WILL REFLECT THE
MODEST WINDS WITH AROUND TWO FEET FOR TUESDAY AND WEDNESDAY
INCREASING SLIGHTLY THURSDAY.
&&
.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 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...MRR
MARINE...REK/JDW/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
238 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...MINOR UPDATES TO INCREASE POP ACROSS THE
AREA WHERE RAIN HAS OVERSPREAD MUCH OF THE CWA. HAVE ALSO TRENDED
TEMPS DOWN SEVERAL DEGREES INLAND DUE TO RAIN-COOLING OF THE AIR
MASS. HAVE ADJUSTED THE TEMP CURVE TO ATTEMPT TO ACCOUNT FOR
RAINFALL AS IT HEADS EAST...WITH NO MORE HEATING EXPECTED TODAY.
HAVE NOTICED A SLIGHT SLOWING OF PRECIP IN HRRR...AND WITH LATEST
TORNADO WATCH (TOA 4) STILL 1 TIER OF COUNTIES WEST OF THE ILM
CWA...STILL BELIEVE ONLY A LIMITED SEVERE THREAT WILL EXIST TODAY
ACROSS WESTERN PORTIONS OF THE AREA. OTRW...PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES
IMPROVE ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES.
0-3 KM SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY
INCREASING UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN
AREAS WITH LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE
REFLECTIVITY AS A GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE
EARLY AFTN...WITH PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN
3P-4P...AND EXITING OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF
GUSTY WINDS FROM WX GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT.
OF COURSE...CANNOT RULE OUT AN ISOLATED DAMAGING WIND
GUST...ESPECIALLY WITHIN ANY BOWING SEGMENTS/STRUCTURES WITHIN THE
LINE...BUT PRIMARY THREATS WILL BE SUB-SEVERE WIND AND SMALL HAIL.
WILL OF COURSE MONITOR...IF MORE SUNSHINE BREAKS OUT THAN
ANTICIPATED...THIS COULD ENHANCE THE SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...COOL...CLOUDY AND MOIST DAY IN STORE FOR
SUNDAY AS A SHORT-LIVED COLD AIR DAMMING SITUATION SETS UP. STEADY
NE FLOW AT THE SURFACE AND EXTENSIVE CLOUD COVER WILL KEEP
AFTERNOON TEMPERATURES A DEGREE OR SO EITHER SIDE OF 50 MOST
LOCATIONS. AS IS TYPICAL FOR THIS TYPE OF PATTERN...EXPECT PATCHY
DRIZZLE OR LIGHT RAIN TO MAKE APPEARANCES AT TIMES...WITH MINIMAL
QPF DUE TO WEAK FORCING AND SHALLOW NATURE OF MOISTURE. THERE WILL
BE A LIMITED DIURNAL RANGE OF TEMPERATURES...WITH LOWS MAINLY IN
THE 40S OVERNIGHT.
WEDGE PATTERN WILL ERODE EARLY ON MONDAY AS A COLD FRONT AND
ASSOCIATED UPPER TROUGH APPROACH FROM THE WEST. FLOW WILL TURN TO
THE SOUTH AND THEN SW MONDAY AFTERNOON...ALLOWING FOR A BIG WARM
UP FROM THE PREVIOUS DAY. EXPECT HIGHS IN THE UPPER 60S TO AROUND
70...ABOUT 20 DEGREES HIGHER THAN ON SUNDAY. FRONT WILL MOVE
ACROSS THE EASTERN CAROLINAS MONDAY EVENING AND OVERNIGHT AND WILL
BE OFFSHORE BY AROUND DAYBREAK ON TUESDAY. MOISTURE WILL BE
LIMITED WITH THIS SYSTEM AND BEST UPPER SUPPORT WILL PASS WELL TO
THE NORTH...SO EXPECT ONLY ISOLATED TO SCATTERED CONVECTION TO
ACCOMPANY FROPA. NOT MUCH IN THE WAY OF COLD ADVECTION WITH THIS
FRONT...SO EXPECT LOWS WILL RANGE FROM THE MID 40S INLAND TO
AROUND 50 AT THE COAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 2:30 PM SATURDAY...MAIN FEATURE FOR THE EXTENDED CONTINUES
TO BE THE CUTOFF MEANDERING ABOUT THE SOUTHWEST AND WHEN IT GETS
KICKED OUT. THE LATEST OPERATIONAL RUN OF THE GFS HAS TRENDED MUCH
SLOWER WHILE PREVIOUS RUNS MAINTAINED MORE OF A ZONAL FLOW. HPC
CONTINUES TO FAVOR THE ECMWF SUITE OF PRODUCTS BASED ON MORE
CONSISTENCY. THESE ARE A BIT SLOWER WITH THE SYSTEM BUT OVERALL
ARE SIMILAR TO THIS TIME YESTERDAY. THE ONLY FORECAST CHANGES WITH
THIS PACKAGE WERE TO DELAY THE POPS SLIGHTLY MAINTAINING THE SAME
STRATEGY AS YESTERDAY WITH INCREASING VALUES FROM LATE THURSDAY
THROUGH THE NEW DAY SATURDAY. ONLY MINOR TWEAKS TO TEMPERATURES
WITH A SLIGHT INCREASE ACROSS THE BOARD TO MATCH HPC NUMBERS AND
ADJACENT OFFICES.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...NO MAJOR CHANGES FOR THIS UPDATE. SEAS HAVE
BEGUN TO INCREASE ACROSS THE SHELF WATERS WITH 41110 REPORTING 4.6
FT AT 12 PM. LATEST SWAN RUN KEEPS SCA SEAS BEYOND 00Z SO WILL
CONSIDER EXTENDING SCA WITH THE 3PM PACKAGE. PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...NELY FLOW OVER THE WATERS ON SUNDAY WILL
TURN SWLY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST.
WINDS WILL RANGE FROM 15 TO 20 KTS EARLY ON SUNDAY BEFORE BECOMING
LIGHT AND VEERING TO THE SE OVERNIGHT WITH THE APPROACH OF THE
COLD FRONT. WINDS WILL PICK UP AGAIN MONDAY AFTERNOON BACK IN THE
15 TO 20 KT RANGE FROM THE SW. COLD FRONT MAY MOVE OFFSHORE BY
AROUND DAYBREAK ON TUESDAY. SEAS WILL RANGE FROM 3 TO 5 FT FOR
MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 2:30 PM SATURDAY...WESTERLY FLOW INITIALLY IN THE WAKE OF THE COLD
FRONT. A SECONDARY PUSH OCCURS LATE TUESDAY INTO WEDNESDAY WHICH
WILL TURN WINDS TO THE NORTHEAST. FINALLY RETURN FLOW SETS UP
THURSDAY AS A SYSTEM TAKES SHAPE WELL TO THE SOUTHWEST. OVERALL WIND
SPEEDS SHOULD REMAIN MODEST WITH THE POSSIBLE EXCEPTION OF LATE INT
HE PERIOD WHEN THE SOUTHWEST FLOW SURGES. SEAS WILL REFLECT THE
MODEST WINDS WITH AROUND TWO FEET FOR TUESDAY AND WEDNESDAY
INCREASING SLIGHTLY THURSDAY.
&&
.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 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...MRR
MARINE...REK/JDW/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1250 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...MINOR UPDATES TO INCREASE POP ACROSS THE
AREA WHERE RAIN HAS OVERSPREAD MUCH OF THE CWA. HAVE ALSO TRENDED
TEMPS DOWN SEVERAL DEGREES INLAND DUE TO RAIN-COOLING OF THE AIR
MASS. HAVE ADJUSTED THE TEMP CURVE TO ATTEMPT TO ACCOUNT FOR
RAINFALL AS IT HEADS EAST...WITH NO MORE HEATING EXPECTED TODAY.
HAVE NOTICED A SLIGHT SLOWING OF PRECIP IN HRRR...AND WITH LATEST
TORNADO WATCH (TOA 4) STILL 1 TIER OF COUNTIES WEST OF THE ILM
CWA...STILL BELIEVE ONLY A LIMITED SEVERE THREAT WILL EXIST TODAY
ACROSS WESTERN PORTIONS OF THE AREA. OTRW...PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES
IMPROVE ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES.
0-3 KM SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY
INCREASING UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN
AREAS WITH LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE
REFLECTIVITY AS A GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE
EARLY AFTN...WITH PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN
3P-4P...AND EXITING OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF
GUSTY WINDS FROM WX GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT.
OF COURSE...CANNOT RULE OUT AN ISOLATED DAMAGING WIND
GUST...ESPECIALLY WITHIN ANY BOWING SEGMENTS/STRUCTURES WITHIN THE
LINE...BUT PRIMARY THREATS WILL BE SUB-SEVERE WIND AND SMALL HAIL.
WILL OF COURSE MONITOR...IF MORE SUNSHINE BREAKS OUT THAN
ANTICIPATED...THIS COULD ENHANCE THE SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...NO MAJOR CHANGES FOR THIS UPDATE. SEAS HAVE
BEGUN TO INCREASE ACROSS THE SHELF WATERS WITH 41110 REPORTING 4.6
FT AT 12 PM. LATEST SWAN RUN KEEPS SCA SEAS BEYOND 00Z SO WILL
CONSIDER EXTENDING SCA WITH THE 3PM PACKAGE. PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.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 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1219 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES IMPROVE
ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES. 0-3 KM
SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY INCREASING
UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN AREAS WITH
LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE REFLECTIVITY AS A
GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE EARLY AFTN...WITH
PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN 3P-4P...AND EXITING
OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF GUSTY WINDS FROM WX
GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT. OF COURSE...CANNOT
RULE OUT AN ISOLATED DAMAGING WIND GUST...ESPECIALLY WITHIN ANY
BOWING SEGMENTS/STRUCTURES WITHIN THE LINE...BUT PRIMARY THREATS
WILL BE SUB-SEVERE WIND AND SMALL HAIL. WILL OF COURSE MONITOR...IF
MORE SUNSHINE BREAKS OUT THAN ANTICIPATED...THIS COULD ENHANCE THE
SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND TRAJECTORIES
...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN THE LOW
50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT AND
REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING LATE
SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO DEVELOP MONDAY
WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.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 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
151 PM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 1100 AM CST/
NUMEROUS UPDATES TO THE FORECAST THIS MORNING. FIRST WAS UNEXPECTED
AREA OF PRECIPITATION WHICH BLOSSOMED EARLY THIS MORNING ACROSS FAR
EASTERN SOUTH DAKOTA...MUCH OF NORTHWEST IOWA...AND SOUTHWEST
MINNESOTA. APPARANT SOURCE OF THE SUDDEN DEVELOPMENT OF SNOWFALL
WAS SEEDER FEEDER AS BLOB OF MID LEVEL CLOUDS PUSHED ACROSS THE
AREA. LOWER CLOUDS WERE LIMITED TO A VERY DENDRITIC DEPTH OF
1500 TO 2500 FT THICKNESS BASED ON RUC/NAM MOISTURE PROFILES AND
OBSERVED CEILINGS. FURTHER SUPPORT IS THE AREA OF MID LEVEL RETURNS
NORTH OF THE CWA WHICH ARE BASED AROUND 8000-9000 FEET. AS FAST AS
PRECIPITATION DEVELOPED...THIS IS ALSO ENDING JUST AS QUICKLY AROUND
THE IMMEDIATE KFSD AREA. HOWEVER..AM WATCHING A COUPLE OF CLOUD
LAYERS ON SATELLITE MOVING DIFFERENT DIRECTION...WITH THE LAST AREA
OF MID CLOUDS IN THE JAMES VALLEY SLIDING EASTWARD. MAY GET A LITTLE
BACK EDGE RESURGENCE IN SNOWFALL AS THIS AREA OF MID CLOUDS GOES
PAST...BUT GENERALLY HAVE COVERAGE OF PRECIP SHIFTING EAST AND
OVERALL INTENSITY OF PRECIPITATION DROPPING OFF AS WELL.
LOWER CLOUDS ARE HOPELESSLY TRAPPED BELOW THE INVERSION AND CLOUD
BEARING WINDS ARE NOT SUPPORTIVE OF ANY AGGRESSIVE EASTWARD PUSH.
THEREFORE...UNLESS THE MOISTURE IS PRECIPITATED OUT OF THE LAYER...
LIKELY THAT THERE WILL BE QUITE A FEW LOW CLOUDS FOR QUITE A BIT
LONGER. RAISED THE SKYCOVER CONSIDERABLY ALONG AND EAST OF
INTERSTATE 29 THIS AFTERNOON...AND TO THE WEST HIGHER CLOUDS WILL BE
EVENING THE PLAYING FIELD WITH TIME AS WELL.
FINALLY...ISSUED A WIND ADVISORY FOR THE HIGHER ELEVATION LOCATIONS
OF SOUTH CENTRAL SD FOR REST OF THIS MORNING AND AFTERNOON...WHERE A
FEW WIND GUSTS OVER 45 MPH ARE MOST LIKELY. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
NUMEROUS AVIATION CONCERNS THIS GO AROUND. WIDESPREAD MVFR CEILINGS
PERSIST ALONG AND EAST OF THE JAMES VALLEY. WITH MOISTURE TRAPPED
BELOW A STRONG INVERSION AND A SOUTH/SOUTHEAST WIND ADVERTISED IN
THE CLOUD BEARING LEVELS...EXPECT VERY LITTLE TO CHANGE OTHER THAN
THE TYPICAL GRADUAL LOWERING OF CEILINGS AS INVERSION SHARPENS.
WINDS WILL ALSO REMAIN STRONG WITH GUSTS OF 30 TO 35 KTS...
ESPECIALLY WEST OF INTERSTATE 29...AND THESE WINDS WILL RESULT IN
SOME AREAS OF BLOWING SNOW...BUT FAR FROM A WIDESPREAD RISK AS SOUTH
GRADIENT IS A MORE STABLE AIRFLOW. ELEVATED LOCATIONS WOULD PROBABLY
FARE THE WORST IN THIS SETUP... WHICH IS NOT WHERE TYPICAL AIRFIELDS
LOCATED. A DISTURBANCE IS EXPECTED TO SPREAD NORTHEAST ACROSS THE
BETTER LOWER TO MID LEVEL BOUNDARY LATER TONIGHT THROUGH SUNDAY
MORNING ACROSS CENTRAL SOUTH DAKOTA...SO LARGEST IMPACT FOR
PRECIPITATION DEVELOPMENT WILL LIKELY BE FOR KHON/KMHE AREAS...
PERHAPS REACHING AS FAR EAST AS INTERSTATE 29 AREA AFTER 16Z. THERE
IS A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 10Z AS INITIAL PV
ADVECTION OCCURS...BUT THE PROBABILITY IS LOW ENOUGH THAT DID NOT
INCLUDE IN TAF AT THIS TIME. HOWEVER...DID MENTION RISK OF FREEZING
RAIN OR SLEET BY MID MORNING...BUT SHOULD BE A FAIRLY NARROW WINDOW
WITH CHANGEOVER TO SNOW THROUGH COOLING OF ATMOSPHERE BY 17Z AT
KHON. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 1030 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY THROUGH 5 PM CST FOR SDZ050-057-063.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1100 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 1100 AM CST/
NUMEROUS UPDATES TO THE FORECAST THIS MORNING. FIRST WAS UNEXPECTED
AREA OF PRECIPITATION WHICH BLOSSOMED EARLY THIS MORNING ACROSS FAR
EASTERN SOUTH DAKOTA...MUCH OF NORTHWEST IOWA...AND SOUTHWEST
MINNESOTA. APPARANT SOURCE OF THE SUDDEN DEVELOPMENT OF SNOWFALL
WAS SEEDER FEEDER AS BLOB OF MID LEVEL CLOUDS PUSHED ACROSS THE
AREA. LOWER CLOUDS WERE LIMITED TO A VERY DENDRITIC DEPTH OF
1500 TO 2500 FT THICKNESS BASED ON RUC/NAM MOISTURE PROFILES AND
OBSERVED CEILINGS. FURTHER SUPPORT IS THE AREA OF MID LEVEL RETURNS
NORTH OF THE CWA WHICH ARE BASED AROUND 8000-9000 FEET. AS FAST AS
PRECIPITATION DEVELOPED...THIS IS ALSO ENDING JUST AS QUICKLY AROUND
THE IMMEDIATE KFSD AREA. HOWEVER..AM WATCHING A COUPLE OF CLOUD
LAYERS ON SATELLITE MOVING DIFFERENT DIRECTION...WITH THE LAST AREA
OF MID CLOUDS IN THE JAMES VALLEY SLIDING EASTWARD. MAY GET A LITTLE
BACK EDGE RESURGENCE IN SNOWFALL AS THIS AREA OF MID CLOUDS GOES
PAST...BUT GENERALLY HAVE COVERAGE OF PRECIP SHIFTING EAST AND
OVERALL INTENSITY OF PRECIPITATION DROPPING OFF AS WELL.
LOWER CLOUDS ARE HOPELESSLY TRAPPED BELOW THE INVERSION AND CLOUD
BEARING WINDS ARE NOT SUPPORTIVE OF ANY AGGRESSIVE EASTWARD PUSH.
THEREFORE...UNLESS THE MOISTURE IS PRECIPITATED OUT OF THE LAYER...
LIKELY THAT THERE WILL BE QUITE A FEW LOW CLOUDS FOR QUITE A BIT
LONGER. RAISED THE SKYCOVER CONSIDERABLY ALONG AND EAST OF
INTERSTATE 29 THIS AFTERNOON...AND TO THE WEST HIGHER CLOUDS WILL BE
EVENING THE PLAYING FIELD WITH TIME AS WELL.
FINALLY...ISSUED A WIND ADVISORY FOR THE HIGHER ELEVATION LOCATIONS
OF SOUTH CENTRAL SD FOR REST OF THIS MORNING AND AFTERNOON...WHERE A
FEW WIND GUSTS OVER 45 MPH ARE MOST LIKELY. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AREA OF MVFR CIGS ACROSS SOUTHEAST SOUTH DAKOTA WILL MOVE ENE THIS
MORNING AS SW WINDS DEVELOP ABOVE THE SURFACE. BASED UPON CURRENT
MOVEMENT...LOW CLOUDS SHOULD MOVE EAST OF KHON AND KFSD BY 14Z AND
KSUX BY 15Z. OTHERWISE...WINDS EXPECTED TO REALLY INCREASE THIS
MORNING WITH WINDS GUSTING OVER 30 KTS EXPECTED IN MOST AREAS BY
EARLY THIS AFTERNOON. WITH FRESH SNOW COVER EXPECT SOME BLOWING SNOW
BUT THE BOUNDARY LAYER IS RELATIVELY STABLE WITH THE WARM AIR
ADVECTION DEVELOPING SO THAT REALLY SHOULD LIMIT THE REDUCED
VISIBILITIES TO ONLY A COUPLE OF HOURS THIS AFTERNOON WHEN WINDS
ARE MOST LIKELY TO GUST OVER 30 KTS. WINDS WILL DECREASE A LITTLE
TONIGHT AND THE MID AND UPPER CLOUDS WILL MOVE OVER. WITH A STRONG
PV ANOMALY MOVING OVER THE 850 MB BOUNDARY IN CENTRAL SD LATE
TONIGHT...DID BRING MVFR CIGS BACK INTO HURON LATE TONIGHT. THERE IS
A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 09Z BUT THE PROBABILITY
IS LOW ENOUGH THAT DID NOT INCLUDE IN TAF AT THIS TIME.
HOWEVER...SNOW...POSSIBLY MIXED WITH FREEZING RAIN...ARE MORE LIKELY
LATE SUNDAY MORNING AND SUNDAY AFTERNOON ACROSS MOST OF SE SD AND
WILL LIKELY IMPACT CIGS AND VSBYS./SCHUMACHER
&&
.PREV DISCUSSION.../ISSUED AT 1030 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY THROUGH 5 PM CST FOR SDZ050-057-063.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1155 AM CST SAT JAN 21 2012
.DISCUSSION...UPDATED FOR 18Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...VARIETY OF FLIGHT RULES XPCTD NEXT 24 HRS. WEAK FRONT
HAS STALLED ACROSS S TX WITH KVCT/KALI REMAINING UNDER STRATUS
DECK WITH IFR CIGS...KCRP IS OVERCAST WITH MVFR...AND KLRD IS AT
VFR. AM XPCTING CLD DECK TO ERODE SOME THIS AFTN WITH VFR/MVFR
DEVELOPING AT TIMES AT KCRP/KVCT/KALI AND VFR PREVAILING AT KLRD.
STRATUS DECK LIKELY TO REDEVELOP AFTER THIS EVENING WITH ALL
TERMINALS XPCTD TO TRANSITION TO MVR/IFR OVERNIGHT AND EVEN LIFR
AT TIMES DUE TO LOW CIGS AND VSBYS. FOG WILL BE POSSIBLE AGAIN BUT
GREATER UNCERTAINTY EXISTS REGARDING TONIGHT/S FOG POTENTIAL AS
COMPARED TO PREVIOUS NIGHTS AND LATER TAF FCSTS MAY NEED TO LOWER
VSBYS FOR AREA TERMINALS. IFR CIGS/VSBYS LIKELY TO PERSIST INTO
SUN MRNG ALL TERMINALS. LIGHT WINDS THIS AFTN FROM N AND E BCMGING
MORE SERLY TONIGHT AND SUN MRNG BUT STILL LIGHT.
&&
.PREV DISCUSSION... /ISSUED 1046 AM CST SAT JAN 21 2012/
DISCUSSION...HAVE LET DENSE FOG ADVISORY EXPIRE AS VISIBILITIES
HAVE IMPROVED. WEAK FRONT AS OF WRITING HAS MOVED THROUGH MOST OF
THE AREA BUT HAS YET TO PUSH ACROSS COASTAL COUNTIES AS MARINE
INFLUENCE IS HELPING STALL PROGRESSION. DRIER AIRMASS HAS FILTERED
INTO NORTHERN ZONES BUT LATEST NAM AND RUC INDICATE SIGNIFICANTLY
DRIER AIR WILL NOT REACH SOUTHERN COUNTIES. HAVE UPDATED SKY
CONDITIONS FOR THIS AFTERNOON AND ALTERED WIND AND TEMPERATURE
DATA TO REFLECT LATEST RUC AND NAM. FORECAST HIGHS ACROSS
NORTHEAST COUNTIES MAY BE A LITTLE GENEROUS BUT WITH CLEARING
SKIES AND DRY AIR WORKING IN TEMPS SHOULD BEGIN TO RISE SOON.
WILL ALSO CONTINUE TO MONITOR MARINE CONDITIONS THROUGH THE DAY
WHERE SEA FOG MAY DEVELOP AT TIMES...POSSIBLY BECOMING LOCALLY
DENSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 75 58 79 55 71 / 10 10 10 10 10
VICTORIA 70 53 76 50 71 / 10 10 10 10 10
LAREDO 79 61 83 54 77 / 0 0 10 10 10
ALICE 78 58 82 55 74 / 0 10 10 10 10
ROCKPORT 69 58 75 56 66 / 10 10 10 10 10
COTULLA 76 53 81 48 74 / 0 0 10 10 10
KINGSVILLE 79 58 81 56 73 / 0 10 10 10 10
NAVY CORPUS 72 58 75 58 67 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AVIATION...HART/79
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1046 AM CST SAT JAN 21 2012
.DISCUSSION...HAVE LET DENSE FOG ADVISORY EXPIRE AS VISIBILITIES
HAVE IMPROVED. WEAK FRONT AS OF WRITING HAS MOVED THROUGH MOST OF
THE AREA BUT HAS YET TO PUSH ACROSS COASTAL COUNTIES AS MARINE
INFLUENCE IS HELPING STALL PROGRESSION. DRIER AIRMASS HAS FILTERED
INTO NORTHERN ZONES BUT LATEST NAM AND RUC INDICATE SIGNIFICANTLY
DRIER AIR WILL NOT REACH SOUTHERN COUNTIES. HAVE UPDATED SKY
CONDITIONS FOR THIS AFTERNOON AND ALTERED WIND AND TEMPERATURE
DATA TO REFLECT LATEST RUC AND NAM. FORECAST HIGHS ACROSS
NORTHEAST COUNTIES MAY BE A LITTLE GENEROUS BUT WITH CLEARING
SKIES AND DRY AIR WORKING IN TEMPS SHOULD BEGIN TO RISE SOON.
WILL ALSO CONTINUE TO MONITOR MARINE CONDITIONS THROUGH THE DAY
WHERE SEA FOG MAY DEVELOP AT TIMES...POSSIBLY BECOMING LOCALLY
DENSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 75 58 79 55 71 / 10 10 10 10 10
VICTORIA 70 53 76 50 71 / 10 10 10 10 10
LAREDO 79 61 83 54 77 / 0 0 10 10 10
ALICE 78 58 82 55 74 / 0 10 10 10 10
ROCKPORT 69 58 75 56 66 / 10 10 10 10 10
COTULLA 76 53 81 48 74 / 0 0 10 10 10
KINGSVILLE 79 58 81 56 73 / 0 10 10 10 10
NAVY CORPUS 72 58 75 58 67 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
319 PM CST SAT JAN 21 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
319 PM CST SAT JAN 21 2012
MAIN FOCUS IS ON A VARIETY OF PRECIPITATION TYPES FOR LATER TONIGHT
THROUGH MONDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING OVER THE WESTERN U.S....RIDGING ACROSS MUCH OF THE
PLAINS...AND TROUGHING OVER SOUTHEAST CANADA. 500MB HEIGHT FALLS IN
12 HOURS ARE AS MUCH AS 170 METERS WITH THE WESTERN TROUGH ACCORDING
TO THE RUC...CENTERED OVER EASTERN NEVADA. THE FORECAST AREA RESIDES
ON THE EAST SIDE OF THE RIDGING...FAVORING HIGH PRESSURE AT THE
SURFACE. THIS HIGH WAS CENTERED OVER LAKE MICHIGAN...AFTER BEING
OVER THE FORECAST AREA EARLY THIS MORNING WHICH ALLOWED FOR THE 10
TO 20 BELOW ZERO READINGS. SOUTHERLY FLOW IS INCREASING ON THE BACK
SIDE OF THE HIGH...ESPECIALLY ACROSS THE PLAINS AHEAD OF A LEE
TROUGH. 850MB PROFILER AND RUC WIND DATA SHOWED SOUTHWEST WINDS OF
35-50 KT FROM KANSAS INTO THE EASTERN DAKOTAS AND WESTERN MINNESOTA.
SOUNDINGS SHOW SOME STRONG WARMING AT 850MB AS A RESULT OF THE
INCREASING WINDS. BETWEEN 00Z AND 12Z...850MB TEMPS ROSE FROM -11C
TO -2C AT OAX...-11C TO +2C AT LBF AND -14C TO +6C AT UNR. THE
SOUTHERLY FLOW IS ALSO ADVECTING STRATUS THAT WAS JUST SOUTH OF THE
FORECAST AREA THIS MORNING BACK TO THE NORTHWEST. THE STRATUS DECK
NOW COVERS MUCH OF IOWA AND THE WESTERN HALF OF MINNESOTA. LAST ITEM
OF NOTE IS A LARGE AREA OF STRATUS ALONG THE GULF COAST...AS WELL AS
HIGHER SURFACE DEWPOINTS. THIS MOISTURE IS IMPORTANT FOR TOMORROW.
MODEL ANALYSIS...MODELS ARE STILL HAVING SOME ISSUES WITH THE
TROUGHING OVER THE WESTERN U.S. AS IT TRACKS INTO THE PLAINS ON
SUNDAY. THE GFS/ECMWF/CANADIAN ARE BY FAR THE DEEPEST... ESPECIALLY
WHEN IT COMES TO THE SHORTWAVE AT THE BASE OF THE TROUGH WHICH
CROSSES THE SOUTHERN PLAINS. THE ECMWF HAS BEEN EXTREMELY CONSISTENT
WITH THE GFS AND CANADIAN TRENDING RAPIDLY TOWARDS THE ECMWF. AS
SUCH...THESE MODELS ALLOW FOR THAT SHORTWAVE TO TURN NEGATIVE TILT
AND LIFT INTO ILLINOIS SUNDAY NIGHT. IMMEDIATELY AHEAD OF THIS
SHORTWAVE THERE IS A DEEPENING SURFACE LOW...WHICH ENDS UP TRACKING
FROM OKLAHOMA ON SUNDAY TO NEAR MILWAUKEE AT 12Z MONDAY. THE 21.12Z
NAM CONTINUES TO SUGGEST A LITTLE MORE PROGRESSIVE TROUGH AND LESS
FOCUS ON THE NEGATIVELY TILT SHORTWAVE...RESULTING IN THE SURFACE
LOW TRACKING FROM SOUTH DAKOTA ON SUNDAY TO THUNDER BAY ONTARIO BY
12Z MONDAY. BASED ON HOW POTENT THE TROUGH LOOKS CROSSING NEVADA
THIS AFTERNOON...NOTED TOO BY THE LIGHTNING ASSOCIATED WITH IT...
THINK THE DEEPER GFS/ECMWF SCENARIOS ARE MORE LIKELY TO OCCUR.
TONIGHT...LOW LEVEL SOUTHERLY FLOW WILL INCREASE TONIGHT AS THE
WESTERN U.S. TROUGH BEGINS TO MOVE INTO THE WESTERN SIDE OF THE
PLAINS. AS THIS SOUTHERLY FLOW INCREASES...THE STRATUS TO OUR SOUTH
AND WEST WILL GRADUALLY OVERSPREAD THE FORECAST AREA...TAKING THE
LONGEST OVER WISCONSIN. IN ADDITION...TEMPERATURES AND DEWPOINTS
SHOULD RISE AS THE WARMER READINGS TO THE SOUTH ADVECT NORTHWARD.
A BIG CONCERN IS SOME OF THE FLURRY ACTIVITY THAT HAS ALREADY
OCCURRED IN THE STRATUS DECK. THERE ARE INDICATIONS THAT THE LIFT
PRODUCING THESE FLURRIES WILL OCCUR AT LEAST OVER NORTHWEST SECTIONS
OF THE FORECAST AREA AFTER MIDNIGHT...AND PERHAPS WESTERN SECTIONS
TOO. HOWEVER...AS THE TEMPERATURES IN THE STRATUS DECK
WARM...WORRIED THAT WE MAY LOSE ICE PRODUCTION...RESULTING IN
FREEZING DRIZZLE. PLACED BOTH A MENTION OF FLURRIES AND PATCHY
FREEZING DRIZZLE AFTER MIDNIGHT OVER NORTHWEST SECTIONS.
SUNDAY...STRONG SOUTHERLY FLOW LOOKS TO CONTINUE WITH THE AREA STILL
AHEAD OF THE UPPER TROUGH MOVING INTO THE PLAINS...AS WELL AS THE
ASSOCIATED SURFACE TROUGH/LOW. THIS SOUTH FLOW SHOULD BRING THE
WARMER AND MORE MOIST AIR ALONG THE GULF COAST NORTHWARD INTO THE
FORECAST AREA. AS A RESULT...THE STRATUS DECK OVER THE FORECAST AREA
SHOULD DEEPEN THROUGH THE DAY. WITH THE STRATUS DECK WARMER THAN
-10C OVER MUCH OF THE AREA THROUGH THE ENTIRE DAY...ENVISIONING ONLY
DRIZZLE. THERE ARE INDICATIONS OF MID AND UPPER LEVEL CLOUDS COMING
ACROSS...WITH LIFT THERE TOO TO PRODUCE ICE...BUT THE DRY LAYER
BETWEEN THESE CLOUDS AND THE LOW STRATUS IS DEEPER AND DRIER THAN
PROGGED TWO DAYS AGO. THEREFORE...ANY ICE PRODUCED ALOFT SHOULD
EVAPORATE BEFORE REACHING THE STRATUS. EVEN IF IT DID REACH THE
STRATUS...THE DRY LAYER HAS TEMPERATURES PROGGED AT 3-6C WHICH WOULD
TEND TO MELT THE ICE. LIFT WITHIN THE STRATUS DECK IS PROGGED TO
INCREASE TOO THROUGH THE DAY...NOTED ON 280-285K SURFACES...WHICH
MAY RESULT IN A CHANGE FROM DRIZZLE TO RAIN. HOWEVER...NONE OF THE
LIFT IS ALL THAT STRONG...SO KEPT THINGS SIMPLE AND STATED DRIZZLE
ALL DAY. QPF/ICE AMOUNTS LIKELY TO BE ONE TO THREE HUNDREDTHS. WHERE
FREEZING DRIZZLE AND DRIZZLE OCCURS WILL BE DICTATED BY SURFACE
TEMPERATURE...TO SOME DEGREE. ONE ISSUE IS THAT WE HAVE HAD A LOT OF
COLD TEMPERATURES RECENTLY...SO EVEN WHERE TEMPERATURES CLIMB ABOVE
FREEZING...UNTREATED SURFACES MAY ICE UP. KEPT PRECIPITATION CHANCES
LOW SINCE THERE STILL IS UNCERTAINTY ON HOW MUCH DRIZZLE WILL FALL.
MOS GUIDANCE QUITE LOW ON NUMBERS...THOUGH 21.15Z SREF DOES INDICATE
60-70 PERCENT OF MEMBERS PRODUCING A 0.01 OR MORE OF QPF. WITH
PRECIPITATION CHANCES RIGHT NOW FORECAST AT BELOW 60 PERCENT...AND
PER COLLABORATION WITH SURROUNDING OFFICES...HELD OFF ON ANY
FREEZING RAIN ADVISORY FOR NOW. DO FEEL THAT AN ADVISORY WILL BE
NEEDED.
SUNDAY NIGHT INTO MONDAY...AS THE LOW DEEPENS AND LIFTS OFF TO THE
NORTHEAST SUNDAY NIGHT...COLDER AIR WILL GRADUALLY FILTER SOUTHEAST
INTO THE FORECAST AREA FROM THE NORTHERN PLAINS. HOW FAST THIS
OCCURS DEPENDS ON THE EXACT TRACK OF THE LOW...WHICH IS STILL FAR
FROM CERTAIN. THEREFORE...POTENTIAL REMAINS FOR DRIZZLE/FREEZING
RAIN UNTIL THE LOW PASSES. EVEN THEN...DEPENDING ON THE LOW
TRACK...THERE COULD STILL BE A WARM LAYER ALOFT THAT HAS TO COOL..
RESULTING IN MIXED PRECIPITATION TYPES. FOR NOW...JUST STUCK WITH A
DRIZZLE/FREEZING DRIZZLE EVENING CHANGING OVER TO RAIN/SNOW AFTER
MIDNIGHT. NEEDLESS TO SAY MORE MODIFICATION WILL BE NEEDED FOR
SUNDAY NIGHT...POSSIBLY INTO EARLY MONDAY AS WELL. SNOW SHOULD
SLOWLY TAPER OFF SOUTHWEST TO NORTHEAST MONDAY AS THE LOW PULLS AWAY
FROM THE AREA. DID RAISE PRECIPITATION CHANCES MONDAY
MORNING...THOUGH...WITH GOOD CONSENSUS OF WRAP AROUND PRECIPITATION
IN THE AREA. SHOULD SEE TEMPERATURES CLIMB SOME SUNDAY NIGHT AS THE
LOW APPROACHES...THEN SLOWLY FALL ON MONDAY AS THE LOW MOVES AWAY.
WINDS SHOULD PICK UP TOO ON MONDAY...ESPECIALLY OVER THE WIND
FAVORED AREAS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. LOOKS LIKE
WINDS SHOULD STAY WELL BELOW ADVISORY...THOUGH.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
319 PM CST SAT JAN 21 2012
AFTER AN ACTIVE SHORT TERM PERIOD...LONG TERM FORECAST AT LEAST AT
THIS TIME LOOKS FAIRLY BENIGN. IN THE MEAN...ALL MODELS ARE IN
AGREEMENT OF A FAST WEST-NORTHWEST PATTERN FROM THE PACIFIC
NORTHWEST INTO OUR REGION...WHICH MAY BECOME A LITTLE MORE
NORTHWESTERLY ON SATURDAY WITH INDICATIONS OF A SHORTWAVE TROUGH
DIGGING DOWN INTO THE FORECAST AREA. THIS PATTERN WILL SUPPORT A
FLOW OF MILD PACIFIC AIR INTO THE FORECAST AREA...NOTED BY 850MB
TEMPS THAT STRUGGLE TO GET COLDER THAN -6C FOR THE MOST PART UNTIL
SATURDAY. THERE ARE A FEW SHORTWAVE TROUGHS PROGGED TO MOVE THROUGH
THE AREA...ONE TUESDAY NIGHT AND WEDNESDAY...AND ANOTHER ON
THURSDAY. NEITHER OF THESE FEATURES PRODUCE MUCH QPF IN MODEL
OUTPUT...PRIMARILY BECAUSE THEY DO NOT HAVE MUCH MOISTURE TO WORK
WITH. THE SYSTEM IN THE SHORT TERM PERIOD PRETTY MUCH SHUNTS ALL
MOISTURE SOUTH AND EAST OF THE AREA. THEREFORE...ONLY SOME SLIGHT
CHANCES REMAIN FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
PRECIPITATION TYPE MAY HAVE TO BE WATCHED FOR THIS TIME
PERIOD...GIVEN THE MILDER 850MB TEMPS. WOULD NOT BE SURPRISED TO SEE
EITHER MIXES WITH RAIN...OR WORSE A LOSS OF ICE RESULTING IN
RAIN/FREEZING RAIN VERSUS SNOW. KEPT PRECIPITATION TYPES AS SNOW
SINCE BOTH DETAILS ARE VERY UNCERTAIN AT THIS TIME.
FOR MUCH OF THE LONG TERM PERIOD...FOLLOWED A CONSENSUS BLEND OF
GUIDANCE FOR BOTH TEMPERATURES AND PRECIPITATION THROUGHOUT THE
LONG TERM PERIOD.
&&
.AVIATION...THROUGH 18Z SUNDAY
1137 AM CST SAT JAN 21 2012
FIRST ISSUE TO CONTEND WITH IS THE LOW CLOUDS ON THE EDGE OF THE
SURFACE RIDGE AXIS AND HOW FAST THEY POSSIBLY RETURN TO THE AREA.
BOTH THE 21.12Z NAM AND 21.15Z RUC SHOW THIS LOW LEVEL MOISTURE
SURGING NORTH INTO WESTERN AND CENTRAL MINNESOTA DURING THE
EVENING. AT THE SAME TIME...A POCKET OF DRY AIR...CURRENTLY OVER
NORTHERN INDIANA AND EASTERN ILLINOIS...GETS PULLED NORTH INTO
WISCONSIN. BOTH MODELS ARE REMARKABLY SIMILAR IN SHOWING THE
MOISTURE AND LOW CLOUDS RETURNING TO KRST THIS EVENING AROUND 03Z
WITH THE DRY AIR HOLDING ON AT KLSE WELL INTO THE NIGHT. THUS DID
NOT RETURN THE LOW CLOUDS TO KLSE UNTIL 08Z. THE NEXT ISSUE IS
WHEN AND IF THERE WILL BE ANY PRECIPITATION ONCE THE LOW CLOUDS
MOVE IN. AGAIN THE NAM AND RUC ARE IN GOOD AGREEMENT IN SHOWING
THE WARM AIR ADVECTION AND OMEGA IN THE 0-2KM LAYER TO BE
MAXIMIZED TONIGHT NORTH OF BOTH TAF SITES SO DID NOT INITIALLY ADD
ANY PRECIPITATION WITH THE RETURN OF THE LOW CLOUDS. LOOKING AT
THE BUFKIT SOUNDINGS...IT LOOKS LIKE IT WILL TAKE UNTIL SUNDAY
MORNING BEFORE THE DEPTH OF THE SATURATED LAYER AND THE OMEGA
THROUGH IT BECOME SUFFICIENT TO SUPPORT ANY PRECIPITATION. ONCE
THIS OCCURS...THE PRECIPITATION SHOULD BE FREEZING DRIZZLE AS THE
DEPTH OF SATURATION IS NOT ENOUGH TO SUPPORT ANY ICE IN THE
CLOUDS. HAVE THUS ADDED THIS TO BOTH TAF SITES IN THE 14 TO 15Z
TIME FRAME. THE FINAL THING TO CONTEND WITH IS THE POSSIBILITY OF
LOW LEVEL WIND SHEAR OVERNIGHT. AS THE LOW LEVEL RIDGE AXIS MOVES
OFF TONIGHT AND STRONG LOW LEVEL LOW PRESSURE BEGINS TO TAKE SHAPE
EAST OF THE ROCKIES...THE LOW LEVEL WINDS ARE EXPECTED TO INCREASE
RAPIDLY ABOVE THE SURFACE INVERSION. WINDS AT 2000 FEET ARE
EXPECTED TO INCREASE TO THE 35 TO 45 KNOT RANGE THIS EVENING AND
EVEN POSSIBLY INCREASE SOME OVERNIGHT. THIS WILL CREATE ABOUT A 25
KNOT DIFFERENCE IN SPEEDS WITH SOME SLIGHT CHANGE IN WIND DIRECTION
AND HAVE INCLUDED WIND SHEAR AT BOTH TAF SITES UNTIL THE INVERSION
IS EXPECTED TO START WEAKENING SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CST SAT JAN 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 AM CST SAT JAN 21 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
230 AM CST SAT JAN 21 2012
PROBLEMATIC FORECAST FOR SUNDAY-SUNDAY NIGHT AS A COMPLEX SCENARIO
BRINGS THE THREAT FOR A WINTERY MIX.
A 500 MB TROUGH STILL SET TO MOVE EAST OUT OF THE ROCKIES...THEN
NORTHEAST ACROSS THE GREAT LAKES BY 12Z MON. MODEL DIFFERENCES
CONTINUE...WITH THE 21.00Z NAM REMAINING THE QUICKER MODEL. IT MOVES
ITS ASSOCIATED SFC LOW OVER LAKE SUPERIOR BY 06Z MON WHILE THE GFS
WOULD SLIDE ITS LOW OVER SOUTHERN WI BY THIS TIME. MEANWHILE...THE
EC CONTINUES TO BE THE SLOWER MODEL...HOLDING ITS SFC LOW BACK OVER
NORTHERN MO...NOT MOVING IT INTO SOUTHEAST WI UNTIL 12Z MON. THE
21.00Z GEM IS CLOSE TO THE EC...WITH THE GFS SEEMING TO BE TRENDING
MORE TOWARD THIS SLOWER SOLUTION. THE NAM IS THE ODD MODEL OUT AND
WILL CRAFT THE FORECAST TOWARD A GFS/EC BLEND.
WHILE THE BRUNT OF THE UPPER LEVEL FORCING WON/T SHIFT ACROSS THE
REGION UNTIL SUNDAY NIGHT...THERE IS SOME LOW LEVEL WARM AIR
ADVECTION AND A BIT OF ISENTROPIC UPGLIDE TO CONTEND WITH.
NORTHWEST-SOUTHEAST RUNNING X-SECTIONS/BUFKIT SOUNDINGS SHOW AN
INCREASE IN THE NEAR SFC SATURATION...BUT ONLY TO ABOUT 850 MB BY
THE AFTERNOON. WITH A GOOD AMOUNT OF WARMING IN THE 925-850 MB
LAYER...THERE WILL BE NO ICE IN THE CLOUD...AND ANY PCPN GENERATED
FROM THE THERMODYNAMICS WOULD BE LIQUID/FREEZING - DEPENDING ON SFC
TEMPS. PROBABLY MORE A DRIZZLE THREAT IN THE MORNING...AND DEEPENING
SATURATION IN THE AFTERNOON MAKING RAIN A BIT MORE LIKELY...IF
ANYTHING WOULD OCCUR. TO MAKE IT LESS COMPLEX...WILL STAY WITH
RAIN/FREEZING RAIN WORDING FOR NOW. THE GFS AND GEM BOTH PRODUCE
SOME LIGHT QPF ON SUNDAY...AND IF THIS MANIFESTS...SOME ICY SPOTS
WOULD DEVELOP WHERE SFC TEMPS ALLOWED. ON THE PLUS SIDE...IT DOES
LOOK LIKE A GOOD PORTION OF THE FORECAST AREA WOULD WARM ABOVE
FREEZING SUNDAY AFTERNOON. THAT SAID...EXPOSED SFCS COULD STILL
ALLOW FOR FREEZING THANKS TO THE RECENT BOUT OF COLD DAYS.
THE SATURATION DEEPENS SUN EVENING...AND THAT WILL RESULT IN A
CHANGE OVER TO SNOW AS ICE IS INTRODUCED INTO THE CLOUD. THIS CHANGE
OVER WILL COINCIDE WITH THE SHORTWAVE MOVING IN...ALONG WITH
STRONGER 700-300 MB QG CONVERGENCE AND SOME FRONTOGENETIC FORCING IN
THE 700-500 MB LAYER. MUCH OF THE EVENING COULD STILL SEE MORE OF A
RAIN/FREEZING RAIN THREAT THOUGH.
THE LOW PRESSURE SYSTEM WILL EXIT INTO SOUTHEAST CANADA MON
EVENING...AND DROP A COUPLE INCHES OF SNOW ACCUMULATION TO NORTHERN
PORTIONS OF THE FORECAST BY THE TIME IT EXITS. ALL IN ALL
THOUGH...THE MIXED PCPN AND THREAT FOR FREEZING RAIN/FREEZING
DRIZZLE APPEARS TO BE THE MAIN CONCERN WITH THIS WEATHER SYSTEM. ITS
EVOLUTION WILL BE MONITORED CLOSELY.
ASIDE FROM THE MIXED BAG OF WINTER WEATHER...THE LOW WILL ALSO USHER
IN A COUPLE WINDY DAYS. SOUTH WINDS WILL PICK UP TONIGHT AND PERSIST
FOR THE EARLY PART OF SUNDAY...AND WILL BE RATHER BLUSTERY AT TIMES.
INCREASING PRESSURE GRADIENT ON THE BACKSIDE OF THE DEPARTING LOW
WILL RESULT IN BLUSTERY NORTHWEST WINDS FOR MONDAY. WHILE WARMER AIR
RETURNS WITH THE SOUTHERLY FETCH...COLD AIR WILL FOLLOW WITH THE
NORTHWEST WINDS...AND HIGHS MONDAY WILL LIKELY OCCUR EARLY IN THE
DAY - STEADY TO SLOWLY FALLING FOR THE REST OF THE DAY.
.LONG TERM...TUESDAY THROUGH FRIDAY
230 AM CST SAT JAN 21 2012
THE GFS AND EC FAVOR SLIDING A SHORTWAVE TROUGH THROUGH A SFC HIGH
TUE NIGHT...BUT ACROSS NORTHERN PORTIONS OF THE REGION. CURRENT
TRACK WOULD APPEAR TO HAVE MINIMAL IMPACT ON THE LOCAL AREA. THE EC
THEN BRINGS A SHARPER/STRONGER UPPER LEVEL TROUGH OVER THE UPPER
MISSISSIPPI RIVER VALLEY FOR WED NIGHT/THU. IT WILL HAVE TO BRING
ITS OWN MOISTURE AND CURRENT QPF VIA THE EC KEEPS THE BETTER PCPN
CHANCES OVER NORTHERN/EASTERN WI. MEANWHILE...THE GFS IS BASICALLY
DRY AS IT HAS ONLY A RIPPLE MOVING NORTH OF THE REGION. THE GEM IS
MORE LIKE THE EC...WHILE THE EC HAS BEEN A BIT MORE CONSISTENT
WITHIN ITSELF COMPARED TO THE GFS. WILL LEAN ON THE
EC/GEM/CONSENSUS FOR DETAILS IN THIS PERIOD. THE MOSTLY ZONAL FLOW
A LOFT LOOKS FAIRLY ACTIVE NEXT WEEK WITH THE MODELS THEN SUGGESTING
ANOTHER SHORTWAVE TROUGH ON EITHER THU-FRI...DEPENDING ON WHICH
MODEL YOU PREFER. THE GFS IS QUICKER THAN THE EC...AND WILL AGAIN
SIDE WITH EC/CONSENSUS FOR NOW. STILL...IT LOOKS LIKE THE
BETTER PCPN CHANCES MAY HOLD NORTH OF THE FORECAST AREA.
&&
.AVIATION...THROUGH 18Z SUNDAY
1137 AM CST SAT JAN 21 2012
FIRST ISSUE TO CONTEND WITH IS THE LOW CLOUDS ON THE EDGE OF THE
SURFACE RIDGE AXIS AND HOW FAST THEY POSSIBLY RETURN TO THE AREA.
BOTH THE 21.12Z NAM AND 21.15Z RUC SHOW THIS LOW LEVEL MOISTURE
SURGING NORTH INTO WESTERN AND CENTRAL MINNESOTA DURING THE
EVENING. AT THE SAME TIME...A POCKET OF DRY AIR...CURRENTLY OVER
NORTHERN INDIANA AND EASTERN ILLINOIS...GETS PULLED NORTH INTO
WISCONSIN. BOTH MODELS ARE REMARKABLY SIMILAR IN SHOWING THE
MOISTURE AND LOW CLOUDS RETURNING TO KRST THIS EVENING AROUND 03Z
WITH THE DRY AIR HOLDING ON AT KLSE WELL INTO THE NIGHT. THUS DID
NOT RETURN THE LOW CLOUDS TO KLSE UNTIL 08Z. THE NEXT ISSUE IS
WHEN AND IF THERE WILL BE ANY PRECIPITATION ONCE THE LOW CLOUDS
MOVE IN. AGAIN THE NAM AND RUC ARE IN GOOD AGREEMENT IN SHOWING
THE WARM AIR ADVECTION AND OMEGA IN THE 0-2KM LAYER TO BE
MAXIMIZED TONIGHT NORTH OF BOTH TAF SITES SO DID NOT INITIALLY ADD
ANY PRECIPITATION WITH THE RETURN OF THE LOW CLOUDS. LOOKING AT
THE BUFKIT SOUNDINGS...IT LOOKS LIKE IT WILL TAKE UNTIL SUNDAY
MORNING BEFORE THE DEPTH OF THE SATURATED LAYER AND THE OMEGA
THROUGH IT BECOME SUFFICIENT TO SUPPORT ANY PRECIPITATION. ONCE
THIS OCCURS...THE PRECIPITATION SHOULD BE FREEZING DRIZZLE AS THE
DEPTH OF SATURATION IS NOT ENOUGH TO SUPPORT ANY ICE IN THE
CLOUDS. HAVE THUS ADDED THIS TO BOTH TAF SITES IN THE 14 TO 15Z
TIME FRAME. THE FINAL THING TO CONTEND WITH IS THE POSSIBILITY OF
LOW LEVEL WIND SHEAR OVERNIGHT. AS THE LOW LEVEL RIDGE AXIS MOVES
OFF TONIGHT AND STRONG LOW LEVEL LOW PRESSURE BEGINS TO TAKE SHAPE
EAST OF THE ROCKIES...THE LOW LEVEL WINDS ARE EXPECTED TO INCREASE
RAPIDLY ABOVE THE SURFACE INVERSION. WINDS AT 2000 FEET ARE
EXPECTED TO INCREASE TO THE 35 TO 45 KNOT RANGE THIS EVENING AND
EVEN POSSIBLY INCREASE SOME OVERNIGHT. THIS WILL CREATE ABOUT A 25
KNOT DIFFERENCE IN SPEEDS WITH SOME SLIGHT CHANGE IN WIND DIRECTION
AND HAVE INCLUDED WIND SHEAR AT BOTH TAF SITES UNTIL THE INVERSION
IS EXPECTED TO START WEAKENING SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 AM CST SAT JAN 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1116 AM CST SAT JAN 21 2012
.AVIATION/18Z TAFS/...VFR SKC FOR MUCH OF THE CWA INTO THE EVENING
HOURS. ONLY CONCERN AREA IS FROM NEAR KMKE SOUTH TO KENW WHERE
LAKE EFFECT MVFR CLOUDS WILL SKIRT THIS AREA. LOW LEVEL RH PROGS
HAVE A PRETTY GOOD HANDLE ON LOCATION OF STRATUS FIELD TO OUR
SOUTH AND SOUTHWEST. THIS WILL START COMING BACK LATER TONIGHT
INTO SUNDAY AS FLOW TURNS MORE SOUTHERLY. BUFKIT SOUNDINGS SHOW
CONSIDERABLE MOISTENING IN THE LOW LAYERS...SO WHILE THE INCREASE
WILL INITIALLY BE MVFR...AS MOISTURE INCREASES...WILL SEE IFR AND
SOME LIFR TAKING SHAPE AS WELL. WILL HOLD OFF ON ANY MENTION OF
DZ/FZDZ IN THE TAFS THROUGH 18Z. BETTER POTENTIAL AFTER 18Z...BUT
CONFIDENCE LOW AT THIS POINT. TEMPS PROGGD IN MANY AREAS TO RISE
ABOVE FREEZING MARK BY ONSET TIME...ESPECIALLY IN EASTERN WI.
PC
&&
.PREV DISCUSSION... /ISSUED 317 AM CST SAT JAN 21 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEAR LAKE MICHIGAN THE MAIN ISSUE WILL BE HANDLING LAKE EFFECT
TRENDS. NORTHEAST WINDS IN SHALLOW LAYER FROM 975 MB TO 900 MB.
LAPSE RATES ARE NOT TO STEEP WITH AROUND 3 C/KM AT MILWAUKEE BUT
NEAR 6C/KM NEAR KENOSHA AT 09Z BUT LAPSE RATES INCREASE TO NEAR
9C/KM AT 18Z WITH INVERSION HEIGHT AROUND 3 THSD FT. LOW LEVEL FLOW
WEAKENS AND BECOMES MORE EAST. THEREFORE EXPECT THE SNOW BAND NEAR
KENOSHA TO CONTINUE TO WEAKEN AND THEN EVENTUALLY BECOME MORE
DIFFUSE WITH GENERAL LIGHT SNOW/FLURRIES NEAR THE LAKE. HRRR SHOWS
THE LAKE BAND PUSHING SOUTH THEN WEAKENING BUT INCREASING IN
COVERAGE. NAM SHOWS SOMETHING SIMILAR.
ELSEWHERE MOISTURE TRAPPED BLOW DEVELOPING INVERSION AROUND
3 THSD FT SHOULD SLOW ANY CLEARING FROM THE WEST. FORECAST
SOUNDINGS SHOW SOME CLEARING POTENTIAL OVER THE FRINGES OF THE
STRATUS SHIELD BUT THEN WITH THE EAST FLOW...LOW LEVELS MOISTEN SO
STRATUS/STRATOCUMULUS COULD EXPAND AGAIN.
MID LEVEL SHORTWAVE OVER THE EASTERN GREAT LAKES EXITS TO THE EAST
WITH MID LEVEL DRYING.
STRONG SHORTWAVE OVER THE PACIFIC NORTHWEST WILL REACH THE ROCKIES
TONIGHT. LOW/MID LEVEL WARM AIR ADVECTION BEGINS BUT THE 850 TO 700
MB LAYER IS FAIRLY DRY SO NOT EXPECTING ANY PRECIPITATION. BY
MIDNIGHT SOUNDINGS SHOW TEMPERATURES AROUND 800 MB ALREADY WARMING
ABOVE 0 CELSIUS OVER MUCH OF THE FORECAST AREA...AND ABOVE 0 C BY
SUNRISE. NAM SHOWS SATURATION BELOW 925 MB BUT DOES NOT APPEAR DEEP
ENOUGH MOIST LAYER FOR FREEZING DRIZZLE.
SUNDAY AND MONDAY...FORECAST CONFIDENCE...MEDIUM
MODELS SLOWLY COMING INTO BETTER AGREEMENT FOR THE SUNDAY/MONDAY LOW
PRESSURE SYSTEM. THE GFS HAS TRENDED TOWARD THE SLOWER ECMWF AND
CANADIAN SOLUTIONS...WHILE THE NAM REMAINS THE QUICKEST. LEANED
FORECAST PRETTY HEAVILY TOWARD CONSISTENT ECMWF.
OVERALL...LOOKS LIKE A CHANCE FOR WARM ADVECTION PRECIP ON SUNDAY.
MID LEVELS ARE QUITE DRY IN SOUNDINGS...WITH VERY LITTLE ICE
EXPECTED. WITH SFC TEMPS BELOW FREEZING TO START THE DAY...KEPT
MENTION OF FREEZING RAIN. MENTIONED RAIN A CHANCE FOR RAIN AS WELL
IN THE AFTERNOON AS TEMPS WARM ABOVE FREEZING. ONLY REASON SNOW WAS
LEFT IN FOR SUNDAY IS THAT SOME MODELS DO SHOW SOME ICE CRYSTAL
POTENTIAL ABOVE THE DRY LAYER. DRY LAYER LOOKS LIKE IT WILL
GENERALLY DRY UP ANY ICE...BUT POTENTIAL FOR SEEDING IS THERE IF DRY
LAYER IS OVERDONE IN MODELS.
PRECIP AMOUNTS EXPECTED TO BE LIGHT DURING THE DAY SUNDAY...SO ANY
ICING WOULD BE FAIRLY LIMITED.
SFC LOW EXPECTED TO MOVE THROUGH SUNDAY NIGHT...ALONG WITH BEST SHOT
FOR PRECIP FROM THIS STORM. ENOUGH OVERLAP BETWEEN MODELS TO BUMP
POPS UP TO CATEGORICAL. LOOKS LIKE MAINLY RAIN EAST...MIXING WITH
SNOW WEST. MAY SEE EVENTUAL CHANGE OVER TO SNOW WEST TO EAST
BEGINNING LATE SUNDAY NIGHT OR MONDAY MORNING...WITH SOME LIGHT
ACCUMULATIONS POSSIBLE.
WITH DEWPOINTS EXPECTED TO GET INTO THE MID 30S OVER THE
SNOWPACK...AND THE SFC LOW COMING RIGHT OVERHEAD...MENTIONED PATCHY
FOG IN THE EAST SUN NIGHT AND MON MORNING.
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS FAIRLY QUIET TUESDAY THROUGH THE REMAINDER OF THE WORK WEEK.
MODELS DEPICTING A SERIES OF WEAK SHORTWAVES TO ROLL THROUGH DURING
THIS PERIOD...POSSIBLY BRINGING SOME FLURRIES OR LIGHT SNOW AT
TIMES. NEAR NORMAL TEMPS TUESDAY EXPECTED TO WARM TO A FEW DEGREES
ABOVE NORMAL FOR WEDNESDAY THROUGH FRIDAY.
AVIATION/12Z TAFS/...
MAINLY MVFR CIGS OVER FAR SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN. LAKE BAND PUSHING SOUTH BUT STRONGEST RADAR RETURNS HAVE
BEEN STAYING OFF SHORE. AS LOW LEVEL FLOW BECOMES MORE EAST LAKE
EFFECT WILL EXPAND IN COVERAGE BUT SHOULD BE FAIRLY LIGHT...ALTHOUGH
SOME AREAS COULD SEE SOME VERY LIGHT ACCUMULATIONS. CIGS/VSBYS WILL
BE MAINLY MVFR.
THE LOW CLOUD SHIELD MAY ERODE SOMEWHAT FROM THE WEST...BUT THEN
WOULD TEND TO EXPAND AGAIN AS EAST FLOW INCREASES THE LOW LEVEL
MOISTURE.
IFR POTENTIAL LATER TONIGHT AS EAST/SOUTHEAST FLOW INCREASES.
MARINE...
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED LATE TONIGHT THROUGH
MONDAY NIGHT AS LOW PRESSURE MOVES EAST AND EXITS THE NORTHERN
PLAINS. BRISK SOUTH WINDS AND HIGH WAVES WILL PREVAIL SATURDAY
NIGHT INTO SUNDAY NIGHT. A COLD FRONT WILL THEN SHIFT THE WINDS TO
THE WEST FOR LATE SUNDAY NIGHT AND INTO MONDAY NIGHT. THE WINDS
WILL CONTINUE TO BE BRISK AND GUSTY AND SMALL CRAFT CONDITIONS
WILL LIKELY PERSIST FOR THIS TIME PERIOD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SUNDAY THROUGH FRIDAY...DDV