Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/29/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
323 PM MST MON FEB 27 2012
.SHORT TERM...UPPER TROUGH HEADING TOWARDS THE GREAT BASIN AT THIS
TIME WITH FAIRLY TIGHT SOUTHERLY FLOW ALOFT OVER THE REGION. AT
THE SURFACE...GUSTY SOUTHERLY WINDS CONTINING ACROSS THE
PLAINS MAINLY FROM DENVER EASTWARD. MODELS STILL PERSISTANT WITH
WEAKENING THAT GRADIENT DURING THE EVENING...WITH SURFACE WINDS
DECREASING A RESULT. WILL CONTINUE THIS TREND. SATELLITE SHOWING
MOISTURE CONTINUING TO SPREAD INTO WESTERN COLORADO...WITH RADAR
SHOWING SOME ECHOES ACROSS THE WESTERN MOUNTAINS. NOT ALOT
CURRENTLY HAPPENING OVER THE NORTHERN AND CENTRAL MOUNTAINS...
PERHAPS A FEW ECHOES ACROSS ZONE 31. AS TROUGH MOVES INTO THE
GREAT BASIN THIS EVENING...SHOULD SEE MOISTURE INCREASE AND SNOW
SPREAD ACROSS THE AREA. SOUTHWEST FLOW ALOFT NOT FAVORABLE FOR
GOOD SNOWFALL AND ACCUMULATIONS...BUT WITH INCREASING ASCENT AND
LAPSE RATES...LIKELY POPS SEEM WARRANTED WITH THE HIGHEST POPS FOR
FAVORED ZONE 31. SNOW AMOUNTS TO BE IN THE 1 TO 3 INCH RANGE.
ACROSS PLAINS....SURFACE WINDS TO BECOME SOUTHWEST DURING THE
EVENING AS THE SOUTHWEST GRADIENT INCREASES. MOISTURE TO INCREASE
ACROSS THE AREA BY MIDNIGHT. LOW LEVELS SLOWING MOISTEN OVERNIGHT
AS LOW LEVEL MOISTURE SPREADS NORTHWEST. QUESTION REMAINS HOW MUCH
LOW LEVEL MOISTURE MAKES IT TO THE FOOTHILLS. LATEST RUC AS WELL
AS THE HI RESOLUTION MODELS BRING THE LOW LEVEL MOISTURE INTO
EASTERN ADAMS AND EASTERN ARAPAHOE COUNTIES AROUND 10Z...ENOUGH
PERHAPS FOR PATCHY FOG. THIS ALREADY IN THE GRIDS. PRECIP CHANCES
LOW OVERNIGHT...WITH THE BEST CHANCE ACROSS ZONE 38 WHERE SOME
BANDED PRECIP IS POSSIBLE. MAY BE A RAIN/SNOW MIX FOR A FEW HOURS.
ON TUESDAY...THE TROUGH IS EXPECTED TO MOVE ACROSS THE REGION WITH
THE BEST DYNAMICS OCCURRING DURING THE MORNING. OROGRAPHICS
IMPROVE DURING THE AFTERNOON BUT LIFT IS EAST OF THE MOUNTAINS AND
MOISTURE DEPTH DECREASES. STILL A DECENT SHOT OF SNOW EXPECTED FOR
THE MOUNTAINS...ESPECIALLY FOR THE MORNING HOURS...WITH ANOTHER 2
TO 5 INCHES. ACROSS PLAINS...BEST CHANCE FOR SNOW LOOKS TO BE
DURING THE MORNING WHEN THE DYNAMICS MOVES OVERHEAD. BUT DOWNSLOPE
WINDS WILL OFFSET THE SNOW POTENTIAL. SO ANY ACCUMULATION SHOULD
BE LESS THAN AN INCH....MAINLY ACROSS ZONE 38. SNOW CHANCES
DECREASE DURING THE AFTERNOON AS TROUGH MOVES INTO THE CENTRAL
PLAINS AND DOWNSLOPE INCREASES. LATEST MODELS STILL SHOW SOME
LIGHT ACCUMULATION ACROSS FAR NORTHEAST CORNER DURING THE
AFTERNOON. WILL KEEP CHANCE POPS THERE...BUT AMOUNTS WILL BE
LIGHT. AS FOR PRECIP TYPE...THICKESS PROGS SUGGEST ALL SNOW.
.LONG TERM...A CLOSED UPPER LEVEL LOW MOVING ACROSS THE NORTHERN
PLAINS WILL BRING A NORTHWEST FLOW ALOFT TO COLORADO TUESDAY NIGHT.
AS THIS SYSTEM EXITS THE REGION...MOUNTAIN SNOW WILL COME TO AN END
DURING THE NIGHT. A STABLE LAYER WILL FORM JUST ABOVE RIDGE TOP AND
CREATE A MOUNTAIN WAVE. WINDS AT RIDGE TOP WILL BE AROUND 50 KNOTS.
THE WAVE WILL ACCELERATE THESE WINDS DOWN THE FOOTHILLS RESUTLING IN
WIND GUSTS UP TO 80 MPH. WILL ISSUE A HIGH WIND WATCH FOR THE
FOOTHILLS AND AREAS AT THE BASE OF THE FOOTHILLS FOR TUESDAY NIGHT
AND EARLY WEDNESDAY MORNING.
THE WINDS WILL QUICKLY DIE OFF WEDNESDAY AS AN UPPER LEVEL RIDGE
QUICKLY PASSES OVER THE STATE. THIS WILL BRING MILD AND DRY
CONDITIONS TO NORTHEAST COLORADO.
NEXT STORM SYSTEM WILL DIG SOUTH ACROSS THE PACIFIC NORTHWEST AND
NORTHERN ROCKIES THURSDAY. THIS SYSTEM WILL LIKELY BRING ANOTHER
SHOT OF SNOW TO THE MOUNTAINS...THURSDAY AND FRIDAY. COLD FRONT WILL
PUSH SOUTH ACROSS NORTHEAST COLORADO THURSDAY. WINDS WILL BECOME
NORTHEAST BEHIND THE FRONT...PRODUCING AN UPSLOPE FLOW. WILL HAVE
SCATTERED POPS IN THE FORECAST THURSDAY AFTERNOON THROUGH THURSDAY
NIGHT. THE AREA WILL BE ON THE BACKSIDE OF THIS SYSTEM ON FRIDAY.
AIRMASS WILL BE SOMEWHAT UNSTABLE AND WILL KEEP LOW POPS FOR
NORTHEAST COLORADO IN THE FORECAST. FOR THE MOUNTAINS...THE SLIGHTLY
UNSTABLE FLOW OVER THE MOUNTAINS WILL PRODUCE SNOW SHOWERS...THUS
WILL HAVE HIGHER POPS OVER THE MOUNTAINS.
UPPER LEVEL RIDGE WILL BE ALONG THE WEST COAST SATURDAY. THIS WILL
PRODUCE A DRY AND MILD NORTHWEST FLOW OVER COLORADO. THE RIDGE WILL
SHIFT EAST THROUGH THE WEEKEND AND EARLY NEXT WEEK. THIS WILL ALLOW
TEMPERATURES TO CLIMB ABOVE NORMAL SUNDAY AND MONDAY AS DRY
CONDITIONS CONTINUE. ON MONDAY...SOME 60S WILL BE POSSIBLE OVER
NORTHEAST COLORADO.
&&
.AVIATION..STRONG SOUTHERLY GRADIENT TO SLOWLY WEAKEN ACROSS
PLAINS THIS EVENING...WITH WINDS DECREASING AT DEN AND APA. WINDS
TO BECOME SOUTHWEST AT ALL THE AREA AIRPORTS BY 05Z AS SOUTHWEST
FLOW ALOFT INCREASES. MOISTURE TO GRADUALLY INCREASE THIS
EVENING...WITH CEILINGS OF 5000-6000 FEET AGL PREVAILING. CHANCE
FOR MVFR CEILINGS AT DEN AND APA AFTER 07Z IF LOW LEVEL MOISTURE
INCREASES FROM THE SOUTHEAST. SLIGHT CHANCE OF SNOW SHOWERS AFTER
06Z...POSSIBLY MIXED WITH RAIN. BEST CHANCE FOR SNOW TUESDAY
MORNING...AS TROUGH MOVES OVERHEAD. VFR CONDITIONS TO
PREVAIL...WITH POSSIBLE MVFR CONDITIONS WITH PASSING SNOW
SHOWERS. WINDS TO SHIFT TO THE NORTHWEST AFTER 16Z...CONTINUING
THROUGH THE DAY WITH SOME GUSTS TO 20 KTS POSSIBLE DURING THE
AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING
FOR COZ035-036-038-039.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MIAMI FL
237 PM EST MON FEB 27 2012
.DISCUSSION...
AS THE AFTERNOON PROGRESSES THE CHANCES FOR STRONG ISOLATED
THUNDERSTORMS IS SOLIDIFYING MORE BASED ON RADAR, SATELLITE AND
SURFACE OBSERVATIONS AROUND THE REGION. THE RUC RAPID REFRESH MODEL
INSISTS IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER
INTERIOR SECTIONS OF SOUTH FLORIDA THIS EVENING. THE RUC SHOWS THE
HIGHEST COVERAGE AFTER 4 PM EST. CURRENTLY, THE RADAR IS SHOWING
AN INCREASE IN SHOWERS SOUTHWEST OF THE LAKE. AT THE PRESENT TIME
THE ONLY LIGHTNING IN THE AREA IS ASSOCIATED WITH THE STORMS NORTH
OF THE LAKE OUTSIDE OF OUR CWA. ANOTHER IMPORTANT FACTOR IS THE
WEST COAST SEA BREEZE, WHICH IS CURRENTLY INLAND PASSED NAPLES, IS
FORECAST TO CONTINUE TO MOVE EAST AND COLLIDE WITH THE EAST AND
SOUTHEAST WINDS OVER THE EASTERN TWO THIRDS OF SOUTH FLORIDA.
TEMPERATURE MEASUREMENTS FROM DIFFERENT AIRPLANES ACROSS SOUTH
FLORIDA INDICATE THAT THE CAP BETWEEN 600 TO 700 MB IS STILL
PRESENT WITH SOME HINTS OF SOME CAP EROSION AS FORECAST BY THE RUC
MODEL.
WITH THESE CONDITIONS THERE IS A SLIGHT CHANCE OF THUNDERSTORMS LATE
THIS AFTERNOON INTO THIS EVENING OVER INTERIOR AREAS OF SOUTH
FLORIDA. THE PRIMARY IMPACTS FROM THE STORMS WILL BE LIGHTNING
STRIKES, HAIL, GUSTY WINDS, AND LOCALLY HEAVY RAINFALL. THE
STRONGEST STORMS WILL BE CAPABLE OF PRODUCING HAIL UP TO NICKEL
SIZE HAIL ESPECIALLY AROUND THE LAKE OKEECHOBEE AREA WHERE THE SEA
BREEZE AND LAKE BREEZES COLLIDE LATE THIS AFTERNOON INTO EARLY
THIS EVENING. THE MOST LIKELY TIME PERIOD FOR CONVECTION WILL BE
FROM 4 TO 8 PM SINCE WE STILL NEED MORE TIME FOR THE CAP TO ERODE
FURTHER.
CURRENT SATELLITE IMAGE SHOWS THAT THE CLOUD TOPS OF MOST OF THE
SHOWERS ARE BEGINNING TO BLOW TO THE EAST SOUTHEAST AT AROUND 20000
FEET, WHICH SHOWS THAT SOME OF THESE SHOWERS ARE BEGINNING TO BREAK
THROUGH THE CAP.
AFTER TODAY THE REST OF THE WEEK LOOKS DRY WITH THE EXCEPTION OF A
FEW SHOWERS STILL POSSIBLE FOR TUESDAY ESPECIALLY OVER THE EAST AND
CENTRAL SECTION OF SOUTH FLORIDA. THE NEXT TIME FOR SHOWERS IS
EXPECTED FOR SUNDAY AS A COLD FRONT IS FORECAST TO APPROACH SOUTH
FLORIDA. HOWEVER, THERE IS STILL CONSIDERABLE UNCERTAINTY ABOUT THE
STRENGTH AND TIMING OF THIS FRONT.
&&
.MARINE...
BENIGN MARINE CONDITIONS WILL ESTABLISH ON TUESDAY WITH THE REST OF
THE WEEK HAVING SEAS OF 2 TO 3 FEET.
&&
NO FIRE WEATHER CONCERNS ARE EXPECTED THIS WEEK. A FEW HOURS OF
RELATIVE HUMIDITY VALUES IN THE 40S ARE POSSIBLE THURSDAY AND FRIDAY
OVER GLADES AND HENDRY...OTHERWISE THE NEXT CHANCE FOR LOWER
RELATIVE HUMIDITY VALUES, BUT STILL ABOVE FIRE THRESHOLDS IS FOR
SUNDAY WITH A LOT OF UNCERTAINTY STILL WITH THIS FORECAST.
&&
.AVIATION...(ISSUED AT 1228 PM EST MON FEB 27 2012)
THE EAST AND WEST COAST SEA BREEZES WILL CONTINUE TO DEVELOP AND
PUSH INLAND THIS AFTERNOON. THIS WILL KEEP THE EAST COAST TAF
SITES IN A SOUTHEAST WIND FLOW AT 15 TO 20 KNOTS...WHILE KAPF TAF
SITE BECOMES SOUTHWEST AT 5 TO 10 KNOTS AROUND 19Z THIS AFTERNOON.
THERE COULD BE A FEW SHOWERS AROUND THE TAF SITES OF
KPBI...KFLL...KFXE...AND KAPF THIS AFTERNOON AS THE SEA BREEZES
PUSHES INLAND. THE WINDS WILL THEN DECREASE TO LESS THAN 5 KNOTS
AT ALL OF THE TAF SITES THIS EVENING INTO TONIGHT AND CONTINUE TO
BE EASTERLY. THE WEATHER WILL ALSO REMAIN DRY TONIGHT AT ALL OF
THE TAF SITES. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR
CONDITIONS THIS AFTERNOON INTO TONIGHT AT ALL OF THE TAF SITES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 83 69 82 / 20 10 10 10
FORT LAUDERDALE 73 83 72 82 / 20 10 10 10
MIAMI 72 84 71 83 / 20 10 10 10
NAPLES 66 86 65 85 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1228 PM EST MON FEB 27 2012
.AVIATION...
THE EAST AND WEST COAST SEA BREEZES WILL CONTINUE TO DEVELOP AND
PUSH INLAND THIS AFTERNOON. THIS WILL KEEP THE EAST COAST TAF
SITES IN A SOUTHEAST WIND FLOW AT 15 TO 20 KNOTS...WHILE KAPF TAF
SITE BECOMES SOUTHWEST AT 5 TO 10 KNOTS AROUND 19Z THIS AFTERNOON.
THERE COULD BE A FEW SHOWERS AROUND THE TAF SITES OF
KPBI...KFLL...KFXE...AND KAPF THIS AFTERNOON AS THE SEA BREEZES
PUSHES INLAND.
THE WINDS WILL THEN DECREASE TO LESS THAN 5 KNOTS AT ALL OF THE
TAF SITES THIS EVENING INTO TONIGHT WHILE BE EASTERLY DIRECTION.
THE WEATHER WILL ALSO REMAIN DRY TONIGHT AT ALL OF THE TAF SITES.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS THIS
AFTERNOON INTO TONIGHT AT ALL OF THE TAF SITES.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 947 AM EST MON FEB 27 2012/
UPDATE...
WE ADDED THE POSSIBILITY OF ISOLATED THUNDERSTORMS FOR THE CENTRAL
AND WESTERN SECTIONS OF SOUTH FLORIDA WITH THIS MORNING UPDATE.
THE MAIN PRECLUDING FACTOR FOR THE FORMATION OF ISOLATED
THUNDERSTORMS IS A MID LEVEL CAP AROUND 700 MB. HOWEVER, SOME OF
THE CAP COULD BE ERODED BY THE COMBINATION OF COLD ADVECTION WEST
OF THE TROUGH LINE AND WARM SURFACE TEMPERATURES IN THE MID 80S
COMBINED WITH BOUNDARY COLLISIONS. THE COMBINATION OF THE EAST FLOW WITH THE
FORMATION OF A WEST COAST SEA BREEZE AND LAKE BREEZE WILL ENHANCE
THE THUNDERSTORM POTENTIAL FOR GLADES, HENDRY, CENTRAL-WESTERN
COLLIER, AS WELL AS WESTERN PALM BEACH AND BROWARD COUNTIES.
RELATED TO THIS CHANGE POPS AND SKY WERE ALSO UPDATED. IF ALL THE
CORRECT INGREDIENTS COME TOGETHER SUCH AS SIGNIFICANT EROSION OF
THE CAP, ENHANCED BOUNDARY COLLISIONS, AND STRONGER COLD ADVECTION
ALOFT THAN FORECAST, AS THE MOST IMPORTANT FACTORS...SMALL HAIL
COULD OCCUR IN SOME SPOTS OF THE NORTHERN COUNTIES. HOWEVER, THE
CONFIDENCE FOR HAIL IS LOW AT THIS TIME FOR SOUTH FLORIDA.
&&
PREV DISCUSSION... /ISSUED 515 AM EST MON FEB 27 2012/
AVIATION...LOW PRES IN THE NE GUF OF MEX WL MOV NE OVR N FLA
WHL HIGH PRES MOVS OFF OF THE MID ATLC COAST INTO THE ATLC. THIS
KEEPS THE PRES GRADIENT ACRS S FLA RATHER HIGH. FAST MOVG WDLY SCT
SHRA WL MOV ONSHR FM THE ATLC WITH BRIEF MVFR CIGS AND PSBL MVFR
VSBY BUT DUE TO THE SPEED OF THE SHRA WL ONLY HV VCSH IN AFFECTED
E COAST TAFS. AN XCPTN WL BE KPBI WHR SHRA MAY BCM SCT AFT 18Z.
SCT020-025 LCLLY BKN BKN040-060 WI HIR LYRS. SFC WND E COAST E-ESE
9-13G20+ KTS THRU 28/00Z THEN DCRG 8-12KTS. AT KAPF SCT025
BKN050-070 WITH BRIEF BKN025 BUT NOT IN TAF. SFC WND E 5-8 KTS
BCMG AFT 13Z ESE-SE 10-13G18KTS. AFT 18Z VCSH INVOF KAPF.
&&
PREV DISCUSSION... /ISSUED 245 AM EST MON FEB 27 2012/
DISCUSSION...ZONAL FLOW PERSISTS ACROSS MUCH OF EASTERN NORTH
AMERICA AND THIS IS NOT CONDUCIVE FOR ANY SIGNIFICANT COLD FRONTS
MOVING DOWN THE PENINSULA ANY TIME SOON. EMBEDDED IN THE FLOW IS
A WEAK MID LEVEL TROUGH IN THE NE GOFMEX AND THIS WILL MOVE ACROSS
NORTH AND CENTRAL FL TODAY WITH LITTLE AFFECTS ON OUR CWA. BOTH
MAV AND MET GUIDANCE SHOW LESS THAN 50 PERCENT POPS FOR ANY OF THE
REGION WITH THE MET HAVING THE LOWEST NUMBERS. THE HRRR DOES SHOW
AN INCREASE IN SHRA COVERAGE BY LATE THIS MORNING ACROSS PALM
BEACH COUNTY AND CONSIDERING IT DOES VERY WELL DURING THE WINTER
MONTHS, HAVE ADJUSTED THE POPS BASED ON THIS GUIDANCE AND THIS
DOES SEEM REASONABLE GIVEN THE LOW IMPACT THIS TROUGH WILL HAVE
FOR S FL. A SFC RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHEAST
STATES INTO THE ATLANTIC AND THIS WILL SHIFT SOUTH OVER THE NEXT
FEW DAYS REACHING S FL BY THE END OF THIS WEEK. THIS WILL MAINTAIN
A BREEZY EAST WIND FLOW THIS MORNING AND SLOWLY WEAKENING
THEREAFTER. ONCE THE TROUGH MOVES TO THE NORTHEAST OF THE AREA,
THE SUBTROPICAL RIDGE WILL BUILD BACK NORTH AS SEVERAL STRONG MID
LEVEL TROUGHS MOVE THROUGH THE ZONAL PATTERN ACROSS THE NORTHERN
TIER OF STATES. ALL OF THIS WILL MAINTAIN A QUIET WX PATTERN
ACROSS FL THROUGH THE WEEK.
BY NEXT WEEKEND, ONE OF THE AFOREMENTIONED TROUGHS WILL BEGIN TO
CARVE OUT A LARGE SCALE TROUGH ACROSS THE EASTERN STATES AND BOTH
THE ECMWF AND GFS SHOW A COLD FRONT MOVING INTO S FL SOMETIME SUNDAY
BUT WITH MOST OF THE ENERGY WITH THIS SYSTEM REMAINING WELL NORTH OF
OUR CWA IT APPEARS THAT IT WILL PROVIDE FOR JUST A SLIGHT CHANCE OF
SHRA.
MARINE...THE GRADIENT FLOW WILL WEAKEN THIS MORNING AS THE RIDGE
OF THE RIDGE OF PRESSURE OVER THE SOUTHEAST STATES BEGINS TO SHIFT
SOUTH. STILL, THERE WILL BE A SCEC STATEMENT FOR AT LEAST THE
FIRST FEW HOURS OF THE FCST AS AN EAST WIND WILL CONTINUE AT
AROUND 15-20 KNOTS BEFORE WEAKENING THIS AFTERNOON.
FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 70 83 69 / 30 20 10 10
FORT LAUDERDALE 82 73 83 72 / 30 20 10 10
MIAMI 83 72 84 71 / 20 20 10 10
NAPLES 85 66 86 65 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION
NWS MIAMI FL
947 AM EST MON FEB 27 2012
.UPDATE...
WE ADDED THE POSSIBILITY OF ISOLATED THUNDERSTORMS FOR THE CENTRAL
AND WESTERN SECTIONS OF SOUTH FLORIDA WITH THIS MORNING UPDATE.
THE MAIN PRECLUDING FACTOR FOR THE FORMATION OF ISOLATED
THUNDERSTORMS IS A MID LEVEL CAP AROUND 700 MB. HOWEVER, SOME OF
THE CAP COULD BE ERODED BY THE COMBINATION OF COLD ADVECTION WEST
OF THE TROUGH LINE AND WARM SURFACE TEMPERATURES IN THE MID 80S
COMBINED WITH BOUNDARY COLLISIONS. THE COMBINATION OF THE EAST FLOW WITH THE
FORMATION OF A WEST COAST SEA BREEZE AND LAKE BREEZE WILL ENHANCE
THE THUNDERSTORM POTENTIAL FOR GLADES, HENDRY, CENTRAL-WESTERN
COLLIER, AS WELL AS WESTERN PALM BEACH AND BROWARD COUNTIES.
RELATED TO THIS CHANGE POPS AND SKY WERE ALSO UPDATED. IF ALL THE
CORRECT INGREDIENTS COME TOGETHER SUCH AS SIGNIFICANT EROSION OF
THE CAP, ENHANCED BOUNDARY COLLISIONS, AND STRONGER COLD ADVECTION
ALOFT THAN FORECAST, AS THE MOST IMPORTANT FACTORS...SMALL HAIL
COULD OCCUR IN SOME SPOTS OF THE NORTHERN COUNTIES. HOWEVER, THE
CONFIDENCE FOR HAIL IS LOW AT THIS TIME FOR SOUTH FLORIDA.
&&
.PREV DISCUSSION... /ISSUED 515 AM EST MON FEB 27 2012/
AVIATION...LOW PRES IN THE NE GUF OF MEX WL MOV NE OVR N FLA
WHL HIGH PRES MOVS OFF OF THE MID ATLC COAST INTO THE ATLC. THIS
KEEPS THE PRES GRADIENT ACRS S FLA RATHER HIGH. FAST MOVG WDLY SCT
SHRA WL MOV ONSHR FM THE ATLC WITH BRIEF MVFR CIGS AND PSBL MVFR
VSBY BUT DUE TO THE SPEED OF THE SHRA WL ONLY HV VCSH IN AFFECTED
E COAST TAFS. AN XCPTN WL BE KPBI WHR SHRA MAY BCM SCT AFT 18Z.
SCT020-025 LCLLY BKN BKN040-060 WI HIR LYRS. SFC WND E COAST E-ESE
9-13G20+ KTS THRU 28/00Z THEN DCRG 8-12KTS. AT KAPF SCT025
BKN050-070 WITH BRIEF BKN025 BUT NOT IN TAF. SFC WND E 5-8 KTS
BCMG AFT 13Z ESE-SE 10-13G18KTS. AFT 18Z VCSH INVOF KAPF.
PREV DISCUSSION... /ISSUED 245 AM EST MON FEB 27 2012/
DISCUSSION...ZONAL FLOW PERSISTS ACROSS MUCH OF EASTERN NORTH
AMERICA AND THIS IS NOT CONDUCIVE FOR ANY SIGNIFICANT COLD FRONTS
MOVING DOWN THE PENINSULA ANY TIME SOON. EMBEDDED IN THE FLOW IS
A WEAK MID LEVEL TROUGH IN THE NE GOFMEX AND THIS WILL MOVE ACROSS
NORTH AND CENTRAL FL TODAY WITH LITTLE AFFECTS ON OUR CWA. BOTH
MAV AND MET GUIDANCE SHOW LESS THAN 50 PERCENT POPS FOR ANY OF THE
REGION WITH THE MET HAVING THE LOWEST NUMBERS. THE HRRR DOES SHOW
AN INCREASE IN SHRA COVERAGE BY LATE THIS MORNING ACROSS PALM
BEACH COUNTY AND CONSIDERING IT DOES VERY WELL DURING THE WINTER
MONTHS, HAVE ADJUSTED THE POPS BASED ON THIS GUIDANCE AND THIS
DOES SEEM REASONABLE GIVEN THE LOW IMPACT THIS TROUGH WILL HAVE
FOR S FL. A SFC RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHEAST
STATES INTO THE ATLANTIC AND THIS WILL SHIFT SOUTH OVER THE NEXT
FEW DAYS REACHING S FL BY THE END OF THIS WEEK. THIS WILL MAINTAIN
A BREEZY EAST WIND FLOW THIS MORNING AND SLOWLY WEAKENING
THEREAFTER. ONCE THE TROUGH MOVES TO THE NORTHEAST OF THE AREA,
THE SUBTROPICAL RIDGE WILL BUILD BACK NORTH AS SEVERAL STRONG MID
LEVEL TROUGHS MOVE THROUGH THE ZONAL PATTERN ACROSS THE NORTHERN
TIER OF STATES. ALL OF THIS WILL MAINTAIN A QUIET WX PATTERN
ACROSS FL THROUGH THE WEEK.
BY NEXT WEEKEND, ONE OF THE AFOREMENTIONED TROUGHS WILL BEGIN TO
CARVE OUT A LARGE SCALE TROUGH ACROSS THE EASTERN STATES AND BOTH
THE ECMWF AND GFS SHOW A COLD FRONT MOVING INTO S FL SOMETIME SUNDAY
BUT WITH MOST OF THE ENERGY WITH THIS SYSTEM REMAINING WELL NORTH OF
OUR CWA IT APPEARS THAT IT WILL PROVIDE FOR JUST A SLIGHT CHANCE OF
SHRA.
MARINE...THE GRADIENT FLOW WILL WEAKEN THIS MORNING AS THE RIDGE
OF THE RIDGE OF PRESSURE OVER THE SOUTHEAST STATES BEGINS TO SHIFT
SOUTH. STILL, THERE WILL BE A SCEC STATEMENT FOR AT LEAST THE
FIRST FEW HOURS OF THE FCST AS AN EAST WIND WILL CONTINUE AT
AROUND 15-20 KNOTS BEFORE WEAKENING THIS AFTERNOON.
FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 70 83 69 / 30 20 10 10
FORT LAUDERDALE 82 73 83 72 / 30 20 10 10
MIAMI 83 72 84 71 / 20 20 10 10
NAPLES 85 66 86 65 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS MIAMI FL
515 AM EST MON FEB 27 2012
.AVIATION...LOW PRES IN THE NE GUF OF MEX WL MOV NE OVR N FLA
WHL HIGH PRES MOVS OFF OF THE MID ATLC COAST INTO THE ATLC. THIS
KEEPS THE PRES GRADIENT ACRS S FLA RATHER HIGH. FAST MOVG WDLY SCT
SHRA WL MOV ONSHR FM THE ATLC WITH BRIEF MVFR CIGS AND PSBL MVFR
VSBY BUT DUE TO THE SPEED OF THE SHRA WL ONLY HV VCSH IN AFFECTED
E COAST TAFS. AN XCPTN WL BE KPBI WHR SHRA MAY BCM SCT AFT 18Z.
SCT020-025 LCLLY BKN BKN040-060 WI HIR LYRS. SFC WND E COAST E-ESE
9-13G20+ KTS THRU 28/00Z THEN DCRG 8-12KTS. AT KAPF SCT025
BKN050-070 WITH BRIEF BKN025 BUT NOT IN TAF. SFC WND E 5-8 KTS
BCMG AFT 13Z ESE-SE 10-13G18KTS. AFT 18Z VCSH INVOF KAPF.
&&
.PREV DISCUSSION... /ISSUED 245 AM EST MON FEB 27 2012/
DISCUSSION...ZONAL FLOW PERSISTS ACROSS MUCH OF EASTERN NORTH
AMERICA AND THIS IS NOT CONDUCIVE FOR ANY SIGNIFICANT COLD FRONTS
MOVING DOWN THE PENINSULA ANY TIME SOON. EMBEDDED IN THE FLOW IS
A WEAK MID LEVEL TROUGH IN THE NE GOFMEX AND THIS WILL MOVE ACROSS
NORTH AND CENTRAL FL TODAY WITH LITTLE AFFECTS ON OUR CWA. BOTH
MAV AND MET GUIDANCE SHOW LESS THAN 50 PERCENT POPS FOR ANY OF THE
REGION WITH THE MET HAVING THE LOWEST NUMBERS. THE HRRR DOES SHOW
AN INCREASE IN SHRA COVERAGE BY LATE THIS MORNING ACROSS PALM
BEACH COUNTY AND CONSIDERING IT DOES VERY WELL DURING THE WINTER
MONTHS, HAVE ADJUSTED THE POPS BASED ON THIS GUIDANCE AND THIS
DOES SEEM REASONABLE GIVEN THE LOW IMPACT THIS TROUGH WILL HAVE
FOR S FL. A SFC RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHEAST
STATES INTO THE ATLANTIC AND THIS WILL SHIFT SOUTH OVER THE NEXT
FEW DAYS REACHING S FL BY THE END OF THIS WEEK. THIS WILL MAINTAIN
A BREEZY EAST WIND FLOW THIS MORNING AND SLOWLY WEAKENING
THEREAFTER. ONCE THE TROUGH MOVES TO THE NORTHEAST OF THE AREA,
THE SUBTROPICAL RIDGE WILL BUILD BACK NORTH AS SEVERAL STRONG MID
LEVEL TROUGHS MOVE THROUGH THE ZONAL PATTERN ACROSS THE NORTHERN
TIER OF STATES. ALL OF THIS WILL MAINTAIN A QUIET WX PATTERN
ACROSS FL THROUGH THE WEEK.
BY NEXT WEEKEND, ONE OF THE AFOREMENTIONED TROUGHS WILL BEGIN TO
CARVE OUT A LARGE SCALE TROUGH ACROSS THE EASTERN STATES AND BOTH
THE ECMWF AND GFS SHOW A COLD FRONT MOVING INTO S FL SOMETIME SUNDAY
BUT WITH MOST OF THE ENERGY WITH THIS SYSTEM REMAINING WELL NORTH OF
OUR CWA IT APPEARS THAT IT WILL PROVIDE FOR JUST A SLIGHT CHANCE OF
SHRA.
MARINE...THE GRADIENT FLOW WILL WEAKEN THIS MORNING AS THE RIDGE
OF THE RIDGE OF PRESSURE OVER THE SOUTHEAST STATES BEGINS TO SHIFT
SOUTH. STILL, THERE WILL BE A SCEC STATEMENT FOR AT LEAST THE
FIRST FEW HOURS OF THE FCST AS AN EAST WIND WILL CONTINUE AT
AROUND 15-20 KNOTS BEFORE WEAKENING THIS AFTERNOON.
FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 70 83 69 / 40 20 10 10
FORT LAUDERDALE 82 73 83 72 / 30 20 10 10
MIAMI 83 72 84 71 / 20 20 10 10
NAPLES 85 66 86 65 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION
NWS MIAMI FL
245 AM EST MON FEB 27 2012
.DISCUSSION...ZONAL FLOW PERSISTS ACROSS MUCH OF EASTERN NORTH
AMERICA AND THIS IS NOT CONDUCIVE FOR ANY SIGNIFICANT COLD FRONTS
MOVING DOWN THE PENINSULA ANY TIME SOON. EMBEDDED IN THE FLOW IS
A WEAK MID LEVEL TROUGH IN THE NE GOFMEX AND THIS WILL MOVE ACROSS
NORTH AND CENTRAL FL TODAY WITH LITTLE AFFECTS ON OUR CWA. BOTH
MAV AND MET GUIDANCE SHOW LESS THAN 50 PERCENT POPS FOR ANY OF THE
REGION WITH THE MET HAVING THE LOWEST NUMBERS. THE HRRR DOES SHOW
AN INCREASE IN SHRA COVERAGE BY LATE THIS MORNING ACROSS PALM
BEACH COUNTY AND CONSIDERING IT DOES VERY WELL DURING THE WINTER
MONTHS, HAVE ADJUSTED THE POPS BASED ON THIS GUIDANCE AND THIS
DOES SEEM REASONABLE GIVEN THE LOW IMPACT THIS TROUGH WILL HAVE
FOR S FL. A SFC RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHEAST
STATES INTO THE ATLANTIC AND THIS WILL SHIFT SOUTH OVER THE NEXT
FEW DAYS REACHING S FL BY THE END OF THIS WEEK. THIS WILL MAINTAIN
A BREEZY EAST WIND FLOW THIS MORNING AND SLOWLY WEAKENING
THEREAFTER. ONCE THE TROUGH MOVES TO THE NORTHEAST OF THE AREA,
THE SUBTROPICAL RIDGE WILL BUILD BACK NORTH AS SEVERAL STRONG MID
LEVEL TROUGHS MOVE THROUGH THE ZONAL PATTERN ACROSS THE NORTHERN
TIER OF STATES. ALL OF THIS WILL MAINTAIN A QUIET WX PATTERN
ACROSS FL THROUGH THE WEEK.
BY NEXT WEEKEND, ONE OF THE AFOREMENTIONED TROUGHS WILL BEGIN TO
CARVE OUT A LARGE SCALE TROUGH ACROSS THE EASTERN STATES AND BOTH
THE ECMWF AND GFS SHOW A COLD FRONT MOVING INTO S FL SOMETIME SUNDAY
BUT WITH MOST OF THE ENERGY WITH THIS SYSTEM REMAINING WELL NORTH OF
OUR CWA IT APPEARS THAT IT WILL PROVIDE FOR JUST A SLIGHT CHANCE OF
SHRA.
&&
.MARINE...THE GRADIENT FLOW WILL WEAKEN THIS MORNING AS THE RIDGE
OF THE RIDGE OF PRESSURE OVER THE SOUTHEAST STATES BEGINS TO SHIFT
SOUTH. STILL, THERE WILL BE A SCEC STATEMENT FOR AT LEAST THE
FIRST FEW HOURS OF THE FCST AS AN EAST WIND WILL CONTINUE AT
AROUND 15-20 KNOTS BEFORE WEAKENING THIS AFTERNOON.
&&
.FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 70 83 69 / 40 20 10 10
FORT LAUDERDALE 82 73 83 72 / 30 20 10 10
MIAMI 83 72 84 71 / 20 20 10 10
NAPLES 85 66 86 65 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
1247 PM EST MON FEB 27 2012
.UPDATE...
/ISSUED AT 1004 AM EST MON FEB 27 2012/
BEST MOISTURE AND LIFT EXITING CENTRAL GA WITH PRECIP CHANCES
DIMINISHING OR HAVE ENDED. STILL GOOD MOISTURE IN PLACE ACROSS
CENTRAL GA AND YOU CAN NOT COMPLETELY RULE OUT SPRINKLES...BRIEF
LIGHT RAIN OR DRIZZLE FOR SOME AREAS. FORECAST HIGH TEMPERATURES
RUNNING NEAR TO SLIGHTLY ABOVE NORMAL. BDL
&&
.PREV DISCUSSION... /ISSUED 639 AM EST MON FEB 27 2012/
SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
CURRENT RADAR LOOP SHOWS SOME SCATTERED TO NUMEROUS SHOWERS
MOVING EAST ACROSS SOUTH GA THIS MORNING. THERE IS A WEAK
SHORTWAVE OVER THE NORTHERN GULF THAT WILL MOVE ACROSS NORTH FL
AND INTO THE ATLANTIC BY 18Z TODAY. THE LOCAL WRF AND HRRR MODELS
SHOW SOME SHOWERS MOVING A BIT NE OVER THE NEXT FEW HOURS BEFORE
MOVING INTO THE CAROLINAS THROUGH THIS AFTERNOON. THEY BOTH SHOW
SHOWERS MOVING INTO CENTRAL GA BUT STAYING SOUTH OF THE ATL AREA.
ONCE THE WAVE MOVES OUT INTO THE ATLANTIC...HIGH PRESSURE OVER THE
GREAT LAKES STATES BUILDS SOUTHWARD BRINGING A BIT OF DRIER AIR
INTO THE REGION. THIS DRIER AIRMASS WILL BE SHORT LIVED AS THE
NEXT DEVELOPING WEATHER SYSTEM MOVES INTO THE AREA. BY 12Z TUE...
A CLOSED LOW DEVELOPS OVER CO AND MOVES NE INTO THE WESTERN GREAT
LAKES STATES BY 12Z WED. THIS LOW CONTINUES TO MOVE EAST INTI THE
NEW ENGLAND STATES THROUGH 12Z THU. THIS LOW CENTERS ASSOCIATED
COLD FRONT MOVES INTO THE MS RIVER VALLEY BY 00Z WED AND INTO NW
GA BY 18Z WED. PRECIPITATION BEGINS MOVING INTO THE STATE WELL
AHEAD OF THE FRONT WITH SHRA/TSRA ACROSS NORTH AND CENTRAL GA
BEGINNING TUESDAY AFTERNOON/EVENING. THE BEST INSTABILITY WITH
THIS SYSTEM WILL BE ASSOCIATED WITH THE FRONTAL PASSAGE BUT ONLY
EXPECTING ISOLATED THUNDERSTORMS AT BEST. CAPES GET INTO THE
300-500 J/KG RANGE BETWEEN 18Z WED AND 00Z THU WITH 0-6KM BULK
SHEAR AROUND 50-60. TEMPS WILL BE ABOUT 8-10 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE FRONTAL SYSTEM MENTIONED IN THE SHORT TERM FINALLY MOVES SOUTH
AND EAST OF THE AREA BY 12-18Z THU. THE FRONT LOOKS TO STALL ACROSS
N FL THEN MOVE BACK NORTHWARD AS A WARM FRONT FRI. ANOTHER LOW
PRESSURE CENTER DEVELOPS OVER CO BY 18Z THU AND IT MOVES RAPIDLY NE
INTO THE GREAT LAKE STATES BY 00Z SAT. THIS SECOND LOW CENTER IS
WHAT ALLOWS THE WARM FRONT TO MOVE BACK ACROSS THE AREA. THIS LOW
CENTERS COLD FRONT MOVES INTI GA LATE FRIDAY NIGHT AND SHOULD BE
SOUTH AND EAST OF THE AREA BY 00Z SUN. THERE IS SOME INSTABILITY
WITH THIS FRONT SO HAVE INTRODUCED THUNDER INTO THE FORECAST BUT
JUST TOO FAR OUT TO DETERMINE JUST HOW INTENSE THIS SECOND SYSTEM
WILL BE. TEMPS CONTINUE TO BE 5-10 DEG ABOVE SEASONAL NORMS THROUGH
DAY 7.
&&
.AVIATION...
18Z UPDATE...
VIS SATL AND AREA OBS TRENDING TOWARD VFR BY 19-20Z THIS AFTN IF NOT
SOONER. LATEST SFC ANALYSIS SHOWS A COLD FRONT SLOWLY PUSHING ACROSS
WEST TN. THE SFC RIDGE TO THE EAST WILL BATTLE WITH WEAK SFC TROUGH
MOVING IN FROM THE NW TO RESULT IN LIGHT 3-4KT WINDS VARYING FROM
NNW TO NNE AT TIMES THROUGH THE AFTERNOON. MODELS AGREE ON FRONT
PUSHING ACROSS ATL AROUND 03Z THIS EVENING... SO WIND DIRECTIONS
SHOULD SETTLE AT 4-5KTS NNE BY THEN. NO -RA OR LOW CIGS EXPECTED
WITH THE FRONT AT ATL FOR NOW... BUT BEHIND THE FRONT... WILL HAVE
TO WATCH THE POTENTIAL FOR MVFR CIGS CLOSELY. MID LEVEL CIGS MOVE
INTO THE AREA BY 19-21Z TUE AS MOIST SW MID LEVEL FLOW OVERRUNS AN
EASTERLY SFC FLOW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON VFR TONIGHT.
HIGH ON REMAINING ELEMENTS.
/39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 44 71 53 / 5 0 20 30
ATLANTA 64 50 71 57 / 0 0 20 30
BLAIRSVILLE 63 40 66 50 / 0 0 20 50
CARTERSVILLE 64 42 71 53 / 0 0 20 40
COLUMBUS 66 50 75 58 / 20 5 10 20
GAINESVILLE 63 47 67 54 / 0 0 20 40
MACON 65 47 73 56 / 20 5 10 10
ROME 66 42 72 54 / 0 0 20 50
PEACHTREE CITY 64 42 71 55 / 5 0 20 30
VIDALIA 65 52 73 57 / 30 5 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1004 AM EST MON FEB 27 2012
.UPDATE...
BEST MOISTURE AND LIFT EXITING CENTRAL GA WITH PRECIP CHANCES
DIMINISHING OR HAVE ENDED. STILL GOOD MOISTURE IN PLACE ACROSS
CENTRAL GA AND YOU CAN NOT COMPLETELY RULE OUT SPRINKLES...BRIEF LIGHT
RAIN OR DRIZZLE FOR SOME AREAS. FORECAST HIGH TEMPERATURES RUNNING
NEAR TO SLIGHTLY ABOVE NORMAL. BDL
&&
.PREV DISCUSSION... /ISSUED 639 AM EST MON FEB 27 2012/
SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
CURRENT RADAR LOOP SHOWS SOME SCATTERED TO NUMEROUS SHOWERS
MOVING EAST ACROSS SOUTH GA THIS MORNING. THERE IS A WEAK
SHORTWAVE OVER THE NORTHERN GULF THAT WILL MOVE ACROSS NORTH FL
AND INTO THE ATLANTIC BY 18Z TODAY. THE LOCAL WRF AND HRRR MODELS
SHOW SOME SHOWERS MOVING A BIT NE OVER THE NEXT FEW HOURS BEFORE
MOVING INTO THE CAROLINAS THROUGH THIS AFTERNOON. THEY BOTH SHOW
SHOWERS MOVING INTO CENTRAL GA BUT STAYING SOUTH OF THE ATL AREA.
ONCE THE WAVE MOVES OUT INTO THE ATLANTIC...HIGH PRESSURE OVER THE
GREAT LAKES STATES BUILDS SOUTHWARD BRINGING A BIT OF DRIER AIR
INTO THE REGION. THIS DRIER AIRMASS WILL BE SHORT LIVED AS THE
NEXT DEVELOPING WEATHER SYSTEM MOVES INTO THE AREA. BY 12Z TUE...
A CLOSED LOW DEVELOPS OVER CO AND MOVES NE INTO THE WESTERN GREAT
LAKES STATES BY 12Z WED. THIS LOW CONTINUES TO MOVE EAST INTI THE
NEW ENGLAND STATES THROUGH 12Z THU. THIS LOW CENTERS ASSOCIATED
COLD FRONT MOVES INTO THE MS RIVER VALLEY BY 00Z WED AND INTO NW
GA BY 18Z WED. PRECIPITATION BEGINS MOVING INTO THE STATE WELL
AHEAD OF THE FRONT WITH SHRA/TSRA ACROSS NORTH AND CENTRAL GA
BEGINNING TUESDAY AFTERNOON/EVENING. THE BEST INSTABILITY WITH
THIS SYSTEM WILL BE ASSOCIATED WITH THE FRONTAL PASSAGE BUT ONLY
EXPECTING ISOLATED THUNDERSTORMS AT BEST. CAPES GET INTO THE
300-500 J/KG RANGE BETWEEN 18Z WED AND 00Z THU WITH 0-6KM BULK
SHEAR AROUND 50-60. TEMPS WILL BE ABOUT 8-10 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE FRONTAL SYSTEM MENTIONED IN THE SHORT TERM FINALLY MOVES SOUTH
AND EAST OF THE AREA BY 12-18Z THU. THE FRONT LOOKS TO STALL ACROSS
N FL THEN MOVE BACK NORTHWARD AS A WARM FRONT FRI. ANOTHER LOW
PRESSURE CENTER DEVELOPS OVER CO BY 18Z THU AND IT MOVES RAPIDLY NE
INTO THE GREAT LAKE STATES BY 00Z SAT. THIS SECOND LOW CENTER IS
WHAT ALLOWS THE WARM FRONT TO MOVE BACK ACROSS THE AREA. THIS LOW
CENTERS COLD FRONT MOVES INTI GA LATE FRIDAY NIGHT AND SHOULD BE
SOUTH AND EAST OF THE AREA BY 00Z SUN. THERE IS SOME INSTABILITY WITH
THIS FRONT SO HAVE INTRODUCED THUNDER INTO THE FORECAST BUT JUST TOO
FAR OUT TO DETERMINE JUST HOW INTENSE THIS SECOND SYSTEM WILL BE.
TEMPS CONTINUE TO BE 5-10 DEG ABOVE SEASONAL NORMS THROUGH DAY 7.
AVIATION...
12Z UPDATE...
CIGS HAVE BEEN COMING DOWN ALL NIGHT AS ADVERTISED WITH MOST SITES
IFR...BUT ATL BRIEFLY IN LIFR AT TIMES. FEEL PRESENCE OF DZ AT ATL
WILL LEAD TO ADDITIONAL INSTANCES OF LIFR THROUGH 14Z AND WILL
CARRY IN TEMPO. SLOW IMPROVEMENT FOR ALL SITES THEREAFTER WITH
MVFR BY 18Z. LOCAL MODELS FINALLY COMING AROUND TO INDICATE A
SHIFT TO NW WINDS THIS AFTERNOON AND HAVE INDICATED SUCH IN NEWEST
TAF SET. SHOULD BE BRIEF THOUGH AS A SHIFT BACK TO NE IS IN STORE
FOR THE OVERNIGHT HOURS. SOME INDICATIONS ALREADY OF SOME LOWERING
CIGS FOR TONIGHT INTO TUE MORNING AND WILL BEGIN TO INDICATE A
DETERIORATING TREND.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON CIG IMPROVEMENT AND WIND SHIFT.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 44 71 53 / 5 0 20 30
ATLANTA 64 50 71 57 / 0 0 20 30
BLAIRSVILLE 63 40 66 50 / 0 0 20 50
CARTERSVILLE 64 42 71 53 / 0 0 20 40
COLUMBUS 66 50 75 58 / 20 5 10 20
GAINESVILLE 63 47 67 54 / 0 0 20 40
MACON 65 47 73 56 / 20 5 10 10
ROME 66 42 72 54 / 0 0 20 50
PEACHTREE CITY 64 42 71 55 / 5 0 20 30
VIDALIA 65 52 73 57 / 30 5 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
639 AM EST MON FEB 27 2012
.PREV DISCUSSION... /ISSUED 414 AM EST MON FEB 27 2012/
SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
CURRENT RADAR LOOP SHOWS SOME SCATTERED TO NUMEROUS SHOWERS MOVING
EAST ACROSS SOUTH GA THIS MORNING. THERE IS A WEAK SHORTWAVE OVER
THE NORTHERN GULF THAT WILL MOVE ACROSS NORTH FL AND INTO THE
ATLANTIC BY 18Z TODAY. THE LOCAL WRF AND HRRR MODELS SHOW SOME
SHOWERS MOVING A BIT NE OVER THE NEXT FEW HOURS BEFORE MOVING INTO
THE CAROLINAS THROUGH THIS AFTERNOON. THEY BOTH SHOW SHOWERS MOVING
INTO CENTRAL GA BUT STAYING SOUTH OF THE ATL AREA. ONCE THE WAVE
MOVES OUT INTO THE ATLANTIC...HIGH PRESSURE OVER THE GREAT LAKES
STATES BUILDS SOUTHWARD BRINGING A BIT OF DRIER AIR INTO THE REGION.
THIS DRIER AIRMASS WILL BE SHORT LIVED AS THE NEXT DEVELOPING
WEATHER SYSTEM MOVES INTO THE AREA. BY 12Z TUE... A CLOSED LOW
DEVELOPS OVER CO AND MOVES NE INTO THE WESTERN GREAT LAKES STATES BY
12Z WED. THIS LOW CONTINUES TO MOVE EAST INTI THE NEW ENGLAND STATES
THROUGH 12Z THU. THIS LOW CENTERS ASSOCIATED COLD FRONT MOVES INTO
THE MS RIVER VALLEY BY 00Z WED AND INTO NW GA BY 18Z WED.
PRECIPITATION BEGINS MOVING INTO THE STATE WELL AHEAD OF THE FRONT
WITH SHRA/TSRA ACROSS NORTH AND CENTRAL GA BEGINNING TUESDAY
AFTERNOON/EVENING. THE BEST INSTABILITY WITH THIS SYSTEM WILL BE
ASSOCIATED WITH THE FRONTAL PASSAGE BUT ONLY EXPECTING ISOLATED
THUNDERSTORMS AT BEST. CAPES GET INTO THE 300-500 J/KG RANGE BETWEEN
18Z WED AND 00Z THU WITH 0-6KM BULK SHEAR AROUND 50-60. TEMPS WILL
BE ABOUT 8-10 DEG ABOVE SEASONAL NORMS THROUGH THE SHORT TERM.
LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE FRONTAL SYSTEM MENTIONED IN THE SHORT TERM FINALLY MOVES SOUTH
AND EAST OF THE AREA BY 12-18Z THU. THE FRONT LOOKS TO STALL ACROSS
N FL THEN MOVE BACK NORTHWARD AS A WARM FRONT FRI. ANOTHER LOW
PRESSURE CENTER DEVELOPS OVER CO BY 18Z THU AND IT MOVES RAPIDLY NE
INTO THE GREAT LAKE STATES BY 00Z SAT. THIS SECOND LOW CENTER IS
WHAT ALLOWS THE WARM FRONT TO MOVE BACK ACROSS THE AREA. THIS LOW
CENTERS COLD FRONT MOVES INTI GA LATE FRIDAY NIGHT AND SHOULD BE
SOUTH AND EAST OF THE AREA BY 00Z SUN. THERE IS SOME INSTABILITY WITH
THIS FRONT SO HAVE INTRODUCED THUNDER INTO THE FORECAST BUT JUST TOO
FAR OUT TO DETERMINE JUST HOW INTENSE THIS SECOND SYSTEM WILL BE.
TEMPS CONTINUE TO BE 5-10 DEG ABOVE SEASONAL NORMS THROUGH DAY 7.
&&
.AVIATION...
12Z UPDATE...
CIGS HAVE BEEN COMING DOWN ALL NIGHT AS ADVERTISED WITH MOST SITES
IFR...BUT ATL BRIEFLY IN LIFR AT TIMES. FEEL PRESENCE OF DZ AT ATL
WILL LEAD TO ADDITIONAL INSTANCES OF LIFR THROUGH 14Z AND WILL
CARRY IN TEMPO. SLOW IMPROVEMENT FOR ALL SITES THEREAFTER WITH
MVFR BY 18Z. LOCAL MODELS FINALLY COMING AROUND TO INDICATE A
SHIFT TO NW WINDS THIS AFTERNOON AND HAVE INDICATED SUCH IN NEWEST
TAF SET. SHOULD BE BRIEF THOUGH AS A SHIFT BACK TO NE IS IN STORE
FOR THE OVERNIGHT HOURS. SOME INDICATIONS ALREADY OF SOME LOWERING
CIGS FOR TONIGHT INTO TUE MORNING AND WILL BEGIN TO INDICATE A
DETERIORATING TREND.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON CIG IMPROVEMENT AND WIND SHIFT.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 44 71 53 / 30 0 20 30
ATLANTA 64 50 71 57 / 20 0 20 30
BLAIRSVILLE 63 40 66 50 / 10 0 20 50
CARTERSVILLE 64 42 71 53 / 10 0 20 40
COLUMBUS 66 50 75 58 / 30 5 10 20
GAINESVILLE 63 47 67 54 / 20 0 20 40
MACON 65 47 73 56 / 50 5 10 10
ROME 66 42 72 54 / 5 0 20 50
PEACHTREE CITY 64 42 71 55 / 20 0 20 30
VIDALIA 65 52 73 57 / 80 5 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
414 AM EST MON FEB 27 2012
.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
CURRENT RADAR LOOP SHOWS SOME SCATTERED TO NUMEROUS SHOWERS MOVING
EAST ACROSS SOUTH GA THIS MORNING. THERE IS A WEAK SHORTWAVE OVER
THE NORTHERN GULF THAT WILL MOVE ACROSS NORTH FL AND INTO THE
ATLANTIC BY 18Z TODAY. THE LOCAL WRF AND HRRR MODELS SHOW SOME
SHOWERS MOVING A BIT NE OVER THE NEXT FEW HOURS BEFORE MOVING INTO
THE CAROLINAS THROUGH THIS AFTERNOON. THEY BOTH SHOW SHOWERS MOVING
INTO CENTRAL GA BUT STAYING SOUTH OF THE ATL AREA. ONCE THE WAVE
MOVES OUT INTO THE ATLANTIC...HIGH PRESSURE OVER THE GREAT LAKES
STATES BUILDS SOUTHWARD BRINGING A BIT OF DRIER AIR INTO THE REGION.
THIS DRIER AIRMASS WILL BE SHORT LIVED AS THE NEXT DEVELOPING
WEATHER SYSTEM MOVES INTO THE AREA. BY 12Z TUE... A CLOSED LOW
DEVELOPS OVER CO AND MOVES NE INTO THE WESTERN GREAT LAKES STATES BY
12Z WED. THIS LOW CONTINUES TO MOVE EAST INTI THE NEW ENGLAND STATES
THROUGH 12Z THU. THIS LOW CENTERS ASSOCIATED COLD FRONT MOVES INTO
THE MS RIVER VALLEY BY 00Z WED AND INTO NW GA BY 18Z WED.
PRECIPITATION BEGINS MOVING INTO THE STATE WELL AHEAD OF THE FRONT
WITH SHRA/TSRA ACROSS NORTH AND CENTRAL GA BEGINNING TUESDAY
AFTERNOON/EVENING. THE BEST INSTABILITY WITH THIS SYSTEM WILL BE
ASSOCIATED WITH THE FRONTAL PASSAGE BUT ONLY EXPECTING ISOLATED
THUNDERSTORMS AT BEST. CAPES GET INTO THE 300-500 J/KG RANGE BETWEEN
18Z WED AND 00Z THU WITH 0-6KM BULK SHEAR AROUND 50-60. TEMPS WILL
BE ABOUT 8-10 DEG ABOVE SEASONAL NORMS THROUGH THE SHORT TERM.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE FRONTAL SYSTEM MENTIONED IN THE SHORT TERM FINALLY MOVES SOUTH
AND EAST OF THE AREA BY 12-18Z THU. THE FRONT LOOKS TO STALL ACROSS
N FL THEN MOVE BACK NORTHWARD AS A WARM FRONT FRI. ANOTHER LOW
PRESSURE CENTER DEVELOPS OVER CO BY 18Z THU AND IT MOVES RAPIDLY NE
INTO THE GREAT LAKE STATES BY 00Z SAT. THIS SECOND LOW CENTER IS
WHAT ALLOWS THE WARM FRONT TO MOVE BACK ACROSS THE AREA. THIS LOW
CENTERS COLD FRONT MOVES INTI GA LATE FRIDAY NIGHT AND SHOULD BE
SOUTH AND EAST OF THE AREA BY 00Z SUN. THERE IS SOME INSTABILITY WITH
THIS FRONT SO HAVE INTRODUCED THUNDER INTO THE FORECAST BUT JUST TOO
FAR OUT TO DETERMINE JUST HOW INTENSE THIS SECOND SYSTEM WILL BE.
TEMPS CONTINUE TO BE 5-10 DEG ABOVE SEASONAL NORMS THROUGH DAY 7.
&&
.AVIATION... 06Z UPDATE...
LOWERING CIGS WILL BE THE RULE FOR TODAY AS CLOUD SHIELD HAS
ALREADY INFILTRATED ALL OF THE TAF SITES. EXPECTING MVFR TO
TRANSITION TO IFR FOR ALL SITES THROUGH 12Z WITH DEVELOPING -RA AS
WELL. MAIN QUESTION INVOLVES THE CHANCES OF SEEING LIFR FOR THE
ATL SITES OR EVEN VLIFR FOR CSG AND MCN. AT THIS TIME...BASED ON
DEVELOPING CLOUD DECK AND OBSERVATIONS TO THE SOUTH...WILL KEEP
ATL AT IFR BUT ANY DEVELOPING DZ SHORTLY AFTER DAYBREAK COULD TAKE
CONDITIONS EVEN LOWER. AS FOR WINDS...MOST MODELS ARE TAKING WINDS
TO NW LATER TODAY WITH THE EXCEPTIONS OF THE LOCAL WRF. BASED ON
ITS GOOD PERFORMANCE IN SUCH EVENTS...HAVE ELECTED TO KEEP WINDS E
TO NE FOR THIS TAF CYCLE BUT WILL LOOK AT CLOSER WITH 12Z
ISSUANCE.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON WINDS AND POTENTIAL FOR LIFR.
HIGH ON IFR DEVELOPMENT AND REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 44 71 53 / 30 0 20 30
ATLANTA 64 50 71 57 / 20 0 20 30
BLAIRSVILLE 63 40 66 50 / 10 0 20 50
CARTERSVILLE 64 42 71 53 / 10 0 20 40
COLUMBUS 66 50 75 58 / 30 5 10 20
GAINESVILLE 63 47 67 54 / 20 0 20 40
MACON 65 47 73 56 / 50 5 10 10
ROME 66 42 72 54 / 5 0 20 50
PEACHTREE CITY 64 42 71 55 / 20 0 20 30
VIDALIA 65 52 73 57 / 80 5 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LINCOLN IL
856 PM CST TUE FEB 28 2012
.DISCUSSION...
ISSUED 856 PM CST TUE FEB 28 2012
SHOWERS AND THUNDERSTORMS HAVE MOVED INTO/EXPANDED ACROSS THE
FORECAST AREA AS A WARM FRONTAL ZONE HAS BEEN PUSHING IN FROM THE
SOUTHWEST. EXPECT THIS TREND TO PERSIST FOR AT LEAST THE NEXT FEW
HOURS. THEN...CHANCES WILL INCREASE AGAIN LATER TONIGHT AS A COLD
FRONT PUSHES IN BEHIND THE WARM FRONT. VIGOROUS THUNDERSTORM
DEVELOPMENT IS OCCURRING ACROSS THE COLD FRONT AT THE
MOMENT...THOUGH THERE IS STILL CONSIDERABLE DOUBT ABOUT THE RISK
OF THESE STRONG STORMS MAKING IT THIS FAR EAST. STILL EXPECT A
DOWNWARD TREND IN THE STORMS BEFORE THEY REACH HERE DUE TO THE
LESS FAVORABLE TIME OF DAY. ALSO...BY THE TIME ANY LINGERING
STORMS GET HERE...THEY SHOULD BE INCREASINGLY ELEVATED.
STILL...WILL NEED TO KEEP AN EYE ON THE SEVERE WIND THREAT WITH
MODELS STILL SUGGESTING A 60-70 KT LOW LEVEL JET AT 850 MB JUST
AHEAD OF THE FRONT.
GOING FORECAST IS IN GOOD SHAPE OVERALL. ONLY MINOR TWEAKS ARE
ANTICIPATED FOR THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 557 PM CST TUE FEB 28 2012
A WARM FRONT WILL LIFT THROUGH THE CENTRAL ILLINOIS TERMINALS THIS
EVENING...WITH SOUTHEAST WINDS TRENDING MORE SOUTHERLY. SHOWERS
AND ISOLATED THUNDERSTORMS IN THE VICINITY OF THIS FRONT WILL
IMPACT THE AREA OVER THE NEXT FEW HOURS INTO THE OVERNIGHT HOURS.
CIGS WILL GRADUALLY LOWER INTO THE MVFR OR IFR CATEGORY AS THE
STEADIER RAINS DEVELOP. A COLD FRONT WILL FOLLOW ACROSS THE AREA
LATE TONIGHT OR EARLY WEDNESDAY BRINGING THE PRECIPITATION RISK TO
AN END. HOWEVER...VERY STRONG SOUTHWEST WINDS WILL EXIST BEHIND
THE FRONT FOR MUCH OF WEDNESDAY...WITH GUSTS AROUND 40 KTS AT
TIMES. THE DRIER AIR FILTERING IN BEHIND THE COLD FRONT SHOULD
QUICKLY PUSH CIGS/VSBYS BACK TO VFR.
BAK
&&
.PREV DISCUSSION...
ISSUED 257 PM CST TUE FEB 28 2012
MAIN CHALLENGES WITH THIS FORECAST PACKAGE ARE WITHIN THE
SHORT-TERM...AS TWO SEPARATE STORM SYSTEMS ARE EXPECTED TO IMPACT
CENTRAL ILLINOIS OVER THE NEXT COUPLE OF DAYS.
SHORT TERM...TONIGHT THROUGH FRIDAY
LOW PRESSURE DEVELOPING IN THE LEE OF THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER MIDWEST TONIGHT...SPREADING SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL ILLINOIS. AIRMASS IS INITIALLY
QUITE DRY...AS EVIDENCED BY 20Z SURFACE DEWPOINTS IN THE MIDDLE
TO UPPER 20S...THEREFORE ONSET OF PRECIP WILL LIKELY HOLD OFF
UNTIL MID TO LATE EVENING...WHEN WINDS BEGIN TO VEER TO A MORE
SOUTHERLY DIRECTION AND LOW-LEVELS MOISTEN. ONCE DEEPER MOISTURE
ARRIVES...SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP ACROSS THE
AREA IN ADVANCE OF A WARM FRONT. ALL MODELS PUSH THIS PRECIP
EASTWARD INTO INDIANA OVERNIGHT...AS THE ENTIRE KILX CWA PUNCHES
INTO THE WARM SECTOR OF THE STORM SYSTEM.
NEXT QUESTION WILL BE HOW MUCH CONVECTION WILL DEVELOP ALONG THE
APPROACHING COLD FRONT LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
HIGH-RES MODELS SUCH AS THE HRRR AND 4KM WRF-NMM SUGGEST A BROKEN
LINE OF STORMS FORMING ALONG THE FRONT AND PUSHING INTO ILLINOIS
AFTER 09Z. FORECAST SOUNDINGS REVEAL A HIGH DEGREE OF LOW-LEVEL
WIND-SHEAR NEAR THE WARM FRONT...HOWEVER ELEVATED INSTABILITY
APPEARS TO BE RATHER MINIMAL. DESPITE MODEST INSTABILITY...VIGOROUS
UPPER DYNAMICS AND STRENGTHENING 850MB JET WILL BE MORE THAN ENOUGH
TO TRIGGER THUNDERSTORMS ALONG THE COLD FRONT TOWARD DAWN WEDNESDAY.
SEVERE THREAT WILL BE LIMITED DUE TO STABLE SURFACE-BASED
LAYER...HOWEVER THINK A FEW STORMS WILL BE STRONG ENOUGH TO MIX
HIGHER MOMENTUM AIR DOWN TO THE SURFACE PRODUCING MARGINALLY
SEVERE WIND GUSTS. PRIMARY TIME FRAME FOR SEVERE POTENTIAL WILL BE
BETWEEN 3 AM AND 9 AM.
COLD FRONT WILL PUSH EASTWARD INTO INDIANA BY AROUND MIDDAY...ENDING
ANY THREAT FOR MORNING SHOWERS/STORMS. DUE TO STRONG SOUTHERLY
FLOW AHEAD OF THE BOUNDARY...HIGH TEMPS WILL SURGE WELL INTO THE
60S ACROSS MUCH OF THE AREA...AND MAY EVEN REACH THE 70 DEGREE MARK
ACROSS THE FAR SOUTHEAST CWA. ONCE THE FRONT PASSES...READINGS WILL
LIKELY FALL A FEW DEGREES DURING THE AFTERNOON. BIG STORY ON
WEDNESDAY WILL BE THE VERY STRONG WINDS...AS PRESSURE GRADIENT
TIGHTENS BETWEEN EXITING FRONT AND APPROACHING HIGH PRESSURE.
SUSTAINED WINDS WILL INCREASE INTO THE 20 TO 30 MPH RANGE...WITH
GUSTS POTENTIALLY EXCEEDING 40 MPH.
QUIET WEATHER WILL BE ON TAP FOR THURSDAY...AS HIGH PRESSURE
DRIFTING OVERHEAD BRINGS CLEAR SKIES AND LIGHT WINDS. THE BREAK IN
THE ACTION WILL BE SHORT-LIVED HOWEVER...AS NEXT UPPER TROUGH
QUICKLY DIGS ACROSS THE WESTERN CONUS AND SURFACE LOW PRESSURE
ONCE AGAIN FORMS IN THE LEE OF THE ROCKIES. MODELS HAVE BEEN
STRUGGLING WITH THE TRACK OF THIS SYSTEM FOR THE PAST FEW
DAYS...AND THE 12Z 28 FEB SUITE IS NO EXCEPTION. THE NAM CONTINUES
TO BE THE FURTHEST EAST WITH THE LOW TRACK...TAKING IT FROM
NORTHERN ARKANSAS AT 12Z FRI TO CENTRAL INDIANA BY 18Z FRI.
ON THE OTHER HAND...THE GFS IS FURTHEST WEST...POSITIONING THE LOW
NEAR QUINCY ILLINOIS BY 18Z FRI. MEANWHILE...THE ECMWF REPRESENTS
A COMPROMISE BETWEEN THE TWO TRACKS AND HAS BEEN THE MOST
CONSISTENT SOLUTION OVER THE PAST FEW RUNS. AS A RESULT...HAVE
TRENDED TOWARD THE ECMWF WITH THE LATE WEEK STORM SYSTEM.
WITH LOW PRESSURE TRACKING ACROSS CENTRAL/EAST-CENTRAL ILLINOIS
DURING THE DAY FRIDAY...SHOWERS AND A FEW THUNDERSTORMS WILL BE
LIKELY. GIVEN EXPECTED TRACK...HAVE FOCUSED THUNDER ACROSS THE
EASTERN TWO-THIRDS OF THE CWA...WHILE KEEPING THE ILLINOIS RIVER
VALLEY ON THE COOL SIDE OF THE SYSTEM AND CONVECTION FREE. AS THE
LOW LIFTS INTO THE GREAT LAKES...W/NW WINDS WILL BRING COLDER AIR
INTO THE REGION BY FRIDAY NIGHT. LINGERING RAIN SHOWERS DURING THE
EVENING MAY CHANGE TO SNOW-SHOWERS OVERNIGHT...HOWEVER NO
ACCUMULATION IS ANTICIPATED.
LONG TERM...SATURDAY THROUGH TUESDAY
COOL/TRANQUIL WEATHER IS IN STORE FOR THE WEEKEND...AS UPPER TROUGH
DIGS OVER THE EASTERN CONUS. WEAK SHORT-WAVE WILL SLIDE
SOUTHEASTWARD INTO THE REGION ON SUNDAY...HOWEVER MOISTURE WILL BE
EXTREMELY LIMITED...SO DO NOT ANTICIPATE ANY PRECIP. THE TROUGH
WILL GRADUALLY SHIFT FURTHER EASTWARD EARLY NEXT WEEK...ALLOWING A
WARMING TREND TO GET UNDERWAY BY MONDAY AND TUESDAY. THE NEXT
SIGNIFICANT STORM SYSTEM WILL LIKELY HOLD OFF UNTIL THE MIDDLE OR
END OF NEXT WEEK...SO DRY WEATHER IS EXPECTED THROUGH THE ENTIRE
EXTENDED.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM TO 6 PM CST WEDNESDAY FOR ILZ027>031-
036>038-040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
557 PM CST TUE FEB 28 2012
.DISCUSSION...
ISSUED 257 PM CST TUE FEB 28 2012
MAIN CHALLENGES WITH THIS FORECAST PACKAGE ARE WITHIN THE
SHORT-TERM...AS TWO SEPARATE STORM SYSTEMS ARE EXPECTED TO IMPACT
CENTRAL ILLINOIS OVER THE NEXT COUPLE OF DAYS.
SHORT TERM...TONIGHT THROUGH FRIDAY
LOW PRESSURE DEVELOPING IN THE LEE OF THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER MIDWEST TONIGHT...SPREADING SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL ILLINOIS. AIRMASS IS INITIALLY
QUITE DRY...AS EVIDENCED BY 20Z SURFACE DEWPOINTS IN THE MIDDLE
TO UPPER 20S...THEREFORE ONSET OF PRECIP WILL LIKELY HOLD OFF
UNTIL MID TO LATE EVENING...WHEN WINDS BEGIN TO VEER TO A MORE
SOUTHERLY DIRECTION AND LOW-LEVELS MOISTEN. ONCE DEEPER MOISTURE
ARRIVES...SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP ACROSS THE
AREA IN ADVANCE OF A WARM FRONT. ALL MODELS PUSH THIS PRECIP
EASTWARD INTO INDIANA OVERNIGHT...AS THE ENTIRE KILX CWA PUNCHES
INTO THE WARM SECTOR OF THE STORM SYSTEM.
NEXT QUESTION WILL BE HOW MUCH CONVECTION WILL DEVELOP ALONG THE
APPROACHING COLD FRONT LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
HIGH-RES MODELS SUCH AS THE HRRR AND 4KM WRF-NMM SUGGEST A BROKEN
LINE OF STORMS FORMING ALONG THE FRONT AND PUSHING INTO ILLINOIS
AFTER 09Z. FORECAST SOUNDINGS REVEAL A HIGH DEGREE OF LOW-LEVEL
WIND-SHEAR NEAR THE WARM FRONT...HOWEVER ELEVATED INSTABILITY
APPEARS TO BE RATHER MINIMAL. DESPITE MODEST INSTABILITY...VIGOROUS
UPPER DYNAMICS AND STRENGTHENING 850MB JET WILL BE MORE THAN ENOUGH
TO TRIGGER THUNDERSTORMS ALONG THE COLD FRONT TOWARD DAWN WEDNESDAY.
SEVERE THREAT WILL BE LIMITED DUE TO STABLE SURFACE-BASED
LAYER...HOWEVER THINK A FEW STORMS WILL BE STRONG ENOUGH TO MIX
HIGHER MOMENTUM AIR DOWN TO THE SURFACE PRODUCING MARGINALLY
SEVERE WIND GUSTS. PRIMARY TIME FRAME FOR SEVERE POTENTIAL WILL BE
BETWEEN 3 AM AND 9 AM.
COLD FRONT WILL PUSH EASTWARD INTO INDIANA BY AROUND MIDDAY...ENDING
ANY THREAT FOR MORNING SHOWERS/STORMS. DUE TO STRONG SOUTHERLY
FLOW AHEAD OF THE BOUNDARY...HIGH TEMPS WILL SURGE WELL INTO THE
60S ACROSS MUCH OF THE AREA...AND MAY EVEN REACH THE 70 DEGREE MARK
ACROSS THE FAR SOUTHEAST CWA. ONCE THE FRONT PASSES...READINGS WILL
LIKELY FALL A FEW DEGREES DURING THE AFTERNOON. BIG STORY ON
WEDNESDAY WILL BE THE VERY STRONG WINDS...AS PRESSURE GRADIENT
TIGHTENS BETWEEN EXITING FRONT AND APPROACHING HIGH PRESSURE.
SUSTAINED WINDS WILL INCREASE INTO THE 20 TO 30 MPH RANGE...WITH
GUSTS POTENTIALLY EXCEEDING 40 MPH.
QUIET WEATHER WILL BE ON TAP FOR THURSDAY...AS HIGH PRESSURE
DRIFTING OVERHEAD BRINGS CLEAR SKIES AND LIGHT WINDS. THE BREAK IN
THE ACTION WILL BE SHORT-LIVED HOWEVER...AS NEXT UPPER TROUGH
QUICKLY DIGS ACROSS THE WESTERN CONUS AND SURFACE LOW PRESSURE
ONCE AGAIN FORMS IN THE LEE OF THE ROCKIES. MODELS HAVE BEEN
STRUGGLING WITH THE TRACK OF THIS SYSTEM FOR THE PAST FEW
DAYS...AND THE 12Z 28 FEB SUITE IS NO EXCEPTION. THE NAM CONTINUES
TO BE THE FURTHEST EAST WITH THE LOW TRACK...TAKING IT FROM
NORTHERN ARKANSAS AT 12Z FRI TO CENTRAL INDIANA BY 18Z FRI.
ON THE OTHER HAND...THE GFS IS FURTHEST WEST...POSITIONING THE LOW
NEAR QUINCY ILLINOIS BY 18Z FRI. MEANWHILE...THE ECMWF REPRESENTS
A COMPROMISE BETWEEN THE TWO TRACKS AND HAS BEEN THE MOST
CONSISTENT SOLUTION OVER THE PAST FEW RUNS. AS A RESULT...HAVE
TRENDED TOWARD THE ECMWF WITH THE LATE WEEK STORM SYSTEM.
WITH LOW PRESSURE TRACKING ACROSS CENTRAL/EAST-CENTRAL ILLINOIS
DURING THE DAY FRIDAY...SHOWERS AND A FEW THUNDERSTORMS WILL BE
LIKELY. GIVEN EXPECTED TRACK...HAVE FOCUSED THUNDER ACROSS THE
EASTERN TWO-THIRDS OF THE CWA...WHILE KEEPING THE ILLINOIS RIVER
VALLEY ON THE COOL SIDE OF THE SYSTEM AND CONVECTION FREE. AS THE
LOW LIFTS INTO THE GREAT LAKES...W/NW WINDS WILL BRING COLDER AIR
INTO THE REGION BY FRIDAY NIGHT. LINGERING RAIN SHOWERS DURING THE
EVENING MAY CHANGE TO SNOW-SHOWERS OVERNIGHT...HOWEVER NO
ACCUMULATION IS ANTICIPATED.
LONG TERM...SATURDAY THROUGH TUESDAY
COOL/TRANQUIL WEATHER IS IN STORE FOR THE WEEKEND...AS UPPER TROUGH
DIGS OVER THE EASTERN CONUS. WEAK SHORT-WAVE WILL SLIDE
SOUTHEASTWARD INTO THE REGION ON SUNDAY...HOWEVER MOISTURE WILL BE
EXTREMELY LIMITED...SO DO NOT ANTICIPATE ANY PRECIP. THE TROUGH
WILL GRADUALLY SHIFT FURTHER EASTWARD EARLY NEXT WEEK...ALLOWING A
WARMING TREND TO GET UNDERWAY BY MONDAY AND TUESDAY. THE NEXT
SIGNIFICANT STORM SYSTEM WILL LIKELY HOLD OFF UNTIL THE MIDDLE OR
END OF NEXT WEEK...SO DRY WEATHER IS EXPECTED THROUGH THE ENTIRE
EXTENDED.
BARNES
&&
.AVIATION...
ISSUED 557 PM CST TUE FEB 28 2012
A WARM FRONT WILL LIFT THROUGH THE CENTRAL ILLINOIS TERMINALS THIS
EVENING...WITH SOUTHEAST WINDS TRENDING MORE SOUTHERLY. SHOWERS
AND ISOLATED THUNDERSTORMS IN THE VICINITY OF THIS FRONT WILL
IMPACT THE AREA OVER THE NEXT FEW HOURS INTO THE OVERNIGHT HOURS.
CIGS WILL GRADUALLY LOWER INTO THE MVFR OR IFR CATEGORY AS THE
STEADIER RAINS DEVELOP. A COLD FRONT WILL FOLLOW ACROSS THE AREA
LATE TONIGHT OR EARLY WEDNESDAY BRINGING THE PRECIPITATION RISK TO
AN END. HOWEVER...VERY STRONG SOUTHWEST WINDS WILL EXIST BEHIND
THE FRONT FOR MUCH OF WEDNESDAY...WITH GUSTS AROUND 40 KTS AT
TIMES. THE DRIER AIR FILTERING IN BEHIND THE COLD FRONT SHOULD
QUICKLY PUSH CIGS/VSBYS BACK TO VFR.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM TO 6 PM CST WEDNESDAY FOR ILZ027>031-
036>038-040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CST MON FEB 27 2012
.DISCUSSION...
916 PM CST
SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST WITH A SOMEWHAT
DIFFUSE YET MARKED COLD FRONT NOW MOVING EAST ACROSS THE FORECAST
AREA. WINDS HAD DIMINISHED AHEAD OF THE FRONT WITH LESS MIXING
AFTER SUNDOWN...BUT BEHIND THE FRONT THE WEST NORTHWEST WINDS ARE
AGAIN GUSTING UPSTREAM...INCLUDING EVEN A FEW 25 TO 30 KT GUSTS IN
NORTHEAST IA AND SOUTHWEST WI. NAM AND RUC SOUNDINGS BOTH DO NOT
ADVERTISE THERMAL PROFILES TO HAVE THESE BROUGHT DOWN IN THE
FORECAST AREA BUT BELIEVE BOTH MODELS MAY NOT BE ADEQUATELY
ANALYZING THE COLD AIR ADVECTION PROFILES WITH THE FRONTAL
PASSAGE. SO OCCASIONAL GUSTS BEING QUITE A WAYS HIGHER THAN
GUIDANCE ADVERTISES ARE POSSIBLE THROUGH THE REST OF TONIGHT AFTER
THE FRONT.
A STRONG 130 KT JET SEEN ON WATER VAPOR AND UPPER AIR ANALYSIS IS
DIRECTLY NORTH OF THE AREA OFFERING SOME FAVORABLE BROAD QG FOR
WEAK ASCENT OVER THE AREA. THE MID TO UPPER LEVELS APPEAR TO BE
MOISTENING ON SATELLITE CHANNELS AND STARTING TO SEE THE FIRST
CLOUD OBSERVATIONS AROUND 8K TO 12K FT. THE RUC SEEMS TO HAVE A
GOOD HANDLE ON THE EVOLUTION GIVEN THE PATTERN...AND EXPECT
CLOUDS TO DEVELOP OVER THE SOUTHEAST FORECAST AREA THROUGH EARLY
OVERNIGHT AND SLOWLY SHIFT EAST.
THE CLOUDS AND WIND FIELD AND ASSOCIATED ADVECTION ARE OF COURSE
DIRECTLY IMPACTING THE TEMPERATURES WHICH HAVE BEEN SOMEWHAT
ERRATICALLY DROPPING...EVEN CLIMBING SLIGHTLY AS MIXING RE-ENSUES
BEFORE DROPPING WITHIN THE APPARENT COLD AIR ADVECTION. HAVE DONE
BEST AS ABLE TO ADJUST HOURLY TRENDS...BUT ALL IN ALL GOING
MINIMUM TEMPERATURE FORECAST STILL LOOKS VERY REASONABLE.
//PREV DISCUSSION...
320 PM CST
FOR THE REMAINDER OF THE AFTERNOON AND EVENING...THE MAIN CONCERN
WILL CONTINUE TO FOCUS ON WINDS. WILL LET THE WIND ADVISORY RIDE
UNTIL EXPIRATION. THE ONLY SITE TO REMAIN NEAR ADVISORY CRITERIA IS
PONTIAC WITH GUSTS TO 35KT/40MPH AT 20Z WITH HIGHER GUSTS OBSERVED
FARTHER SOUTH. SINCE THERE WILL STILL BE A COUPLE MORE HOURS WITH
STRONG GUST POTENTIAL...WILL LET THE ADVISORY RIDE RATHER THAN
CANCEL EARLY. OTHERWISE...THE FORECAST IS GENERALLY ON TRACK WITH
MILD CONDITIONS OVER THE REGION. TEMPERATURES OVER THE NORTHWESTERN
PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA...REMAIN A BIT
COOLER THAT THE REST OF THE AREA DUE TO THE RESIDUAL SNOW COVER.
HOWEVER...STRONG WARM ADVECTION AHEAD OF THE STRONG LOW PRESSURE
SYSTEM APPROACHING THE UPPER MISSISSIPPI VALLEY HAS ALLOWED
TEMPERATURES TO REACH WELL INTO THE 50S ELSEWHERE. EXPECT WINDS TO
BEGIN TO DROP OFF EARLY THIS EVENING AS THE FRONTAL TROUGH CROSSES
THE MISSISSIPPI RIVER...RELAXING THE PRESSURE GRADIENT. STILL
EXPECT A WEAK COLD FRONT TO PUSH SEWD THROUGH THE CWA OVERNIGHT
TONIGHT. GIVEN GENERALLY DRY CONDITIONS IN PLACE...DO NOT EXPECT
ANY PCPN WITH THE FROPA...AND ACTUALLY ONLY SOME INCREASING CLOUD
COVER OVER NWRN IL WITH SOME BACKWASH CLOUD WRAPPING AROUND THE SWRN
PERIPHERY OF THE LOW. COOLER AIR AND HIGH PRESSURE WILL BUILD IN
BEHIND THE EXITING LOW AND TEMPS OVERNIGHT TONIGHT SHOULD DROP INTO
THE MIDDLE 20S ALG AND WEST OF THE I-39 CORRIDOR AND THE THE UPPER
20S TO LOWER 30S ELSEWHERE.
FOR THE SHORT TERM FORECAST PERIOD...FROM MONDAY THROUGH
WEDNESDAY...THE PERIOD WILL START OUT QUIET ON MONDAY AS HIGH
PRESSURE PASSES THROUGH THE UPPER MIDWEST AND GREAT LAKES REGIONS.
SKIES WILL GENERALLY BE MOSTLY SUNNY...THOUGH TEMPERATURES WILL BE
NEAR OR SLIGHTLY BELOW NORMAL...RANGING FROM THE UPPER 30S NORTH OF
I-80 AND THE LOWER 40S TO THE SOUTH AND LOWS TUESDAY MORNING WILL
DROP INTO THE 20S. THE NEXT CHANCE FOR PCPN WILL COME ON TUESDAY AS
THE STRONG PACIFIC SYSTEM LIFTS OUT OF THE CENTRAL ROCKIES AND
ACROSS THE UPPER MISSISSIPPI VALLEY. THE LATEST MODEL TRENDS
CONTINUE TO SLOW DOWN THE PROGRESS OF THE SYSTEM SLIGHTLY...WITH THE
MODELS IN GENERALLY GOOD AGREEMENT ON NOT INTRODUCING PCPN INTO THE
WRN PORTIONS OF THE CWA UNTIL LATE TUESDAY MORNING...AND THEN
SPREADING EWD ACROSS THE CWA THROUGH THE DAY. THE STRONGEST SFC AND
UPPER LEVEL FORCING WILL NOT BE IN PLACE UNTIL TUESDAY NIGHT. WHILE
THERE WILL AN INCREASE IN LOW LEVEL MOISTURE AS THE GULF OF MEXICO
OPENS UP IN ADVANCE OF THE SFC LOW...HAVE SOME CONCERN ABOUT THE
THUNDER POTENTIAL WITH THE SYSTEM. FOR ONE THING...THE BEST FORCING
WILL NOT BE IN PLACE UNTIL THE EVENING HOURS AND THE CWA WILL BE
NORTH OF THE ASSOCIATED WARM FRONT. SOME MODEST ISENTROPIC LIFT AND
MODEST ELEVATED INSTABILITY SHOULD BE IN PLACE...BUT GIVEN THE
EXPECTED TRACK OF THE SFC LOW THROUGH THE UPPER MISSISSIPPI VALLEY
AND WISCONSIN...AT THIS POINT...IT DOES NOT LOOK LIKE THE CWA WILL
EVER BE IN A WARM SECTOR ENVIRONMENT. SO...WILL KEEP THE CHANCE
THUNDER IN THE FORECAST FOR TUESDAY EVENING...BUT HAVE TRIMMED BACK
THE TS POTENTIAL FOR THE OVERNIGHT HOURS AS THE COLD FRONT CROSSES
THE AREA AT AN UNFAVORABLE TIME AND THEN A MID LEVEL DRY SLOT PUSHES
IN VERY QUICKLY FOLLOWING THE FROPA. THERE SHOULD BE A BREAK IN THE
PCPN BY WEDNESDAY MORNING AS THE DRY SLOT MOVES OVERHEAD...BUT AS
THE SFC LOW MOVES OFF TO THE EAST...THERE WILL BE A CHANCE OF SOME
LIGHT SNOW OR A RAIN/SNOW MIX ON THE BACKSIDE OF THE EXITING SYSTEM
FOR WEDNESDAY AFTERNOON AND EVENING.
FOR THE LONGER TERM FORECAST PERIOD...FROM THURSDAY THROUGH
SUNDAY...THE MEDIUM RANGE GUIDANCE IS RELATIVELY CONSISTENT IN
INDICATING A FAIRLY PROGRESSIVE PATTERN WITH INCREASING AMPLITUDE.
THE STORM TRACK SHOULD BE A SERIES OF PACIFIC ORIGIN SYSTEMS WITH NO
SIGNIFICANT ARCTIC INFLUENCE. THE TREND THROUGH THE LONGER TERM
WILL BE FOR ABOVE NORMAL TEMPERATURES THROUGH FRIDAY WITH PERIODIC
LOW PCPN CHANCES. THE STRONGEST UPPER LEVEL LOW IS ADVERTISED TO
CROSS THE UPPER MIDWEST BY NEXT WEEKEND...WHICH SHOULD BRING COOLER
CONDITIONS AND PERHAPS A CHANCE FOR SOME LIGHT SNOW...ESPECIALLY FOR
THE NORTHERN PORTIONS OF THE CWA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* LIGHT SW-WSW WIND BECOMING W WITH SPORADIC GUSTS 15-20 KTS
DURING PREDAWN...THEN BECOMING GUSTY 20-25 KTS AFTER SUNRISE
BEFORE DIMINISHING STEADILY IN THE AFTERNOON.
* LOW PROBABILITY FOR A BRIEF FEW HOUR PERIOD OF A BROKEN HIGH MVR
CEILING IN THE 2500-3000 FT AGL RANGE MID-MORNING TO MIDDAY
MONDAY.
TRS
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER FAR NORTHWEST WISCONSIN LATE THIS EVENING...WITH
SURGING COLD FRONT ARCING SOUTH THROUGH LAKE MICHIGAN TO ABOUT
THE IL/IN STATE LINE AT 05Z. WINDS HAVE SHIFTED WEST BEHIND THE
FRONT...THOUGH DIRECTION DOES VARY A BIT 260-280 DEGREES. MODEST
BUT NOTICEABLE PRESSURE RISE BUBBLE SPREADING ACROSS NORTHERN IL
MAY ALLOW SITES TO GUST A LITTLE SPORADICALLY PRIOR TO SUNRISE.
AFTER SUNRISE...DEEPENING OF LOW LEVEL MIXED LAYER AND STRONGER
PUSH OF COLD ADVECTION SHOULD ALLOW MORE UNIFORMLY GUSTY WEST
WINDS WITH GUSTS AROUND 25 KTS DURING THE MORNING. SURFACE LOW
MOVES OFF INTO SOUTHERN ONTARIO BY EARLY AFTERNOON...AND SPRAWLING
AREA OF HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH THE EVENING
WHICH WILL ALLOW WINDS TO DECREASE STEADILY DURING THE AFTERNOON
HOURS. THE SURFACE HIGH PRESSURE RIDGE WILL MOVE ACROSS THE
TERMINALS DURING THE LATE EVENING/OVERNIGHT HOURS...WITH WINDS
LIKELY BECOMING LIGHT/VARIABLE AFTER SUNSET.
WITH FAIRLY DRY MID/LOW LEVELS...ONLY SOME PATCHY SPARSE VFR
MID/HIGH CLOUD TO CONTEND WITH OVERNIGHT. WITH STEEPENING OF LOW
LEVEL LAPSE RATES AFTER SUNRISE MONDAY THERE WILL LIKELY BE SOME
FLAT STRATOCU DEVELOPMENT WITH BASES IN THE 2000-3000 FT AGL
RANGE. THERE IS SOME POTENTIAL THAT THIS WOULD DEVELOP BRIEFLY
INTO AN MVFR CEILING IN THE 2500-3000 FT RANGE LATE MORNING...
THOUGH CONFIDENCE IS LOW ENOUGH AND THE CEILING WOULD LIKELY LAST
A SHORT ENOUGH TIME TO LEAVE IT OUT OF THE TAFS AT THIS TIME. ANY
CU/STRATOCU WOULD LIKELY CLEAR OUT BY MID AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN WIND TRENDS...THOUGH MODERATE CONFIDENCE IN
SPORADIC GUST SPEEDS PRIOR TO SUNRISE.
* HIGH CONFIDENCE IN PREVAILING VFR CONDITIONS THROUGH PERIOD.
* LOW CONFIDENCE IN BRIEF PERIOD OF MVFR 2500-3000 FT BROKEN
STRATOCU DECK MID-MORNING/MIDDAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...CHANCE OF RAIN/SNOW CHANGING TO RAIN BY AFTERNOON. MVFR
POSSIBLE. MORE RAIN AND POSSIBLY A THUNDERSTORM TUESDAY NIGHT.
WEDNESDAY...CHANCE OF RAIN/SNOW WEDNESDAY AFTERNOON THEN A CHANCE
OF SNOW SHOWERS WEDNESDAY NIGHT. MVFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...CHANCE OF RAIN/SNOW...MVFR POSSIBLE.
SATURDAY...CHANCE OF LIGHT SNOW...MVFR POSSIBLE.
RATZER
&&
.MARINE...
227 AM CST
AN ACTIVE WEATHER PATTERN IS EXPECTED OVER THE UPCOMING WEEK. THIS
MORNING...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
CONTINUE TO PUSH EAST WITH A TRAILING COLD FRONT SWEEPING ACROSS
LAKE MICHIGAN. WINDS WITHIN THE FRONTAL TROUGH HAVE WEAKENED...BUT
ARE EXPECTED TO PICK UP AGAIN OUT OF THE WEST-NORTHWEST BEHIND THE
FRONT AS THE PRESSURE GRADIENT ONCE AGAIN TIGHTENS. WINDS TO AROUND
30 KT ARE EXPECTED OVER THE OPEN WATERS. WILL ISSUE A SMALL CRAFT
ADVISORY FOR LATE THIS MORNING THROUGH EARLY THIS EVENING FOR THE
INDIANA AND ILLINOIS NEARSHORE WATERS.
HIGH PRESSURE BUILDS ACROSS THE LAKE LATE TONIGHT AND WILL ALLOW
WINDS TO DIMINISH BRIEFLY. NEXT LOW PRESSURE SYSTEM BEGINS TO
DEEPEN OVER THE PLAINS TUESDAY AND PASSES OVER SOUTHERN LAKE
MICHIGAN WEDNESDAY. THIS SYSTEM MAY BRING A FEW THUNDERSTORMS TO
SOUTHERN LAKE MICHIGAN...WITH SOUTHEAST TO EASTERLY GALES AHEAD OF
THE LOW ON WEDNESDAY. ANOTHER AREA OF LOW PRESSURE WILL PASS OVER
LAKE MICHIGAN LATE FRIDAY INTO SATURDAY. DETAILS OF THIS SYSTEM
ARE STILL UNCERTAIN...BUT THERE IS ONCE AGAIN POTENTIAL FOR GALES
ACROSS THE LAKE. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 AM MONDAY TO 4 PM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
156 AM CST MON FEB 27 2012
.DISCUSSION...
916 PM CST
SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST WITH A SOMEWHAT
DIFFUSE YET MARKED COLD FRONT NOW MOVING EAST ACROSS THE FORECAST
AREA. WINDS HAD DIMINISHED AHEAD OF THE FRONT WITH LESS MIXING
AFTER SUNDOWN...BUT BEHIND THE FRONT THE WEST NORTHWEST WINDS ARE
AGAIN GUSTING UPSTREAM...INCLUDING EVEN A FEW 25 TO 30 KT GUSTS IN
NORTHEAST IA AND SOUTHWEST WI. NAM AND RUC SOUNDINGS BOTH DO NOT
ADVERTISE THERMAL PROFILES TO HAVE THESE BROUGHT DOWN IN THE
FORECAST AREA BUT BELIEVE BOTH MODELS MAY NOT BE ADEQUATELY
ANALYZING THE COLD AIR ADVECTION PROFILES WITH THE FRONTAL
PASSAGE. SO OCCASIONAL GUSTS BEING QUITE A WAYS HIGHER THAN
GUIDANCE ADVERTISES ARE POSSIBLE THROUGH THE REST OF TONIGHT AFTER
THE FRONT.
A STRONG 130 KT JET SEEN ON WATER VAPOR AND UPPER AIR ANALYSIS IS
DIRECTLY NORTH OF THE AREA OFFERING SOME FAVORABLE BROAD QG FOR
WEAK ASCENT OVER THE AREA. THE MID TO UPPER LEVELS APPEAR TO BE
MOISTENING ON SATELLITE CHANNELS AND STARTING TO SEE THE FIRST
CLOUD OBSERVATIONS AROUND 8K TO 12K FT. THE RUC SEEMS TO HAVE A
GOOD HANDLE ON THE EVOLUTION GIVEN THE PATTERN...AND EXPECT
CLOUDS TO DEVELOP OVER THE SOUTHEAST FORECAST AREA THROUGH EARLY
OVERNIGHT AND SLOWLY SHIFT EAST.
THE CLOUDS AND WIND FIELD AND ASSOCIATED ADVECTION ARE OF COURSE
DIRECTLY IMPACTING THE TEMPERATURES WHICH HAVE BEEN SOMEWHAT
ERRATICALLY DROPPING...EVEN CLIMBING SLIGHTLY AS MIXING RE-ENSUES
BEFORE DROPPING WITHIN THE APPARENT COLD AIR ADVECTION. HAVE DONE
BEST AS ABLE TO ADJUST HOURLY TRENDS...BUT ALL IN ALL GOING
MINIMUM TEMPERATURE FORECAST STILL LOOKS VERY REASONABLE.
//PREV DISCUSSION...
320 PM CST
FOR THE REMAINDER OF THE AFTERNOON AND EVENING...THE MAIN CONCERN
WILL CONTINUE TO FOCUS ON WINDS. WILL LET THE WIND ADVISORY RIDE
UNTIL EXPIRATION. THE ONLY SITE TO REMAIN NEAR ADVISORY CRITERIA IS
PONTIAC WITH GUSTS TO 35KT/40MPH AT 20Z WITH HIGHER GUSTS OBSERVED
FARTHER SOUTH. SINCE THERE WILL STILL BE A COUPLE MORE HOURS WITH
STRONG GUST POTENTIAL...WILL LET THE ADVISORY RIDE RATHER THAN
CANCEL EARLY. OTHERWISE...THE FORECAST IS GENERALLY ON TRACK WITH
MILD CONDITIONS OVER THE REGION. TEMPERATURES OVER THE NORTHWESTERN
PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA...REMAIN A BIT
COOLER THAT THE REST OF THE AREA DUE TO THE RESIDUAL SNOW COVER.
HOWEVER...STRONG WARM ADVECTION AHEAD OF THE STRONG LOW PRESSURE
SYSTEM APPROACHING THE UPPER MISSISSIPPI VALLEY HAS ALLOWED
TEMPERATURES TO REACH WELL INTO THE 50S ELSEWHERE. EXPECT WINDS TO
BEGIN TO DROP OFF EARLY THIS EVENING AS THE FRONTAL TROUGH CROSSES
THE MISSISSIPPI RIVER...RELAXING THE PRESSURE GRADIENT. STILL
EXPECT A WEAK COLD FRONT TO PUSH SEWD THROUGH THE CWA OVERNIGHT
TONIGHT. GIVEN GENERALLY DRY CONDITIONS IN PLACE...DO NOT EXPECT
ANY PCPN WITH THE FROPA...AND ACTUALLY ONLY SOME INCREASING CLOUD
COVER OVER NWRN IL WITH SOME BACKWASH CLOUD WRAPPING AROUND THE SWRN
PERIPHERY OF THE LOW. COOLER AIR AND HIGH PRESSURE WILL BUILD IN
BEHIND THE EXITING LOW AND TEMPS OVERNIGHT TONIGHT SHOULD DROP INTO
THE MIDDLE 20S ALG AND WEST OF THE I-39 CORRIDOR AND THE THE UPPER
20S TO LOWER 30S ELSEWHERE.
FOR THE SHORT TERM FORECAST PERIOD...FROM MONDAY THROUGH
WEDNESDAY...THE PERIOD WILL START OUT QUIET ON MONDAY AS HIGH
PRESSURE PASSES THROUGH THE UPPER MIDWEST AND GREAT LAKES REGIONS.
SKIES WILL GENERALLY BE MOSTLY SUNNY...THOUGH TEMPERATURES WILL BE
NEAR OR SLIGHTLY BELOW NORMAL...RANGING FROM THE UPPER 30S NORTH OF
I-80 AND THE LOWER 40S TO THE SOUTH AND LOWS TUESDAY MORNING WILL
DROP INTO THE 20S. THE NEXT CHANCE FOR PCPN WILL COME ON TUESDAY AS
THE STRONG PACIFIC SYSTEM LIFTS OUT OF THE CENTRAL ROCKIES AND
ACROSS THE UPPER MISSISSIPPI VALLEY. THE LATEST MODEL TRENDS
CONTINUE TO SLOW DOWN THE PROGRESS OF THE SYSTEM SLIGHTLY...WITH THE
MODELS IN GENERALLY GOOD AGREEMENT ON NOT INTRODUCING PCPN INTO THE
WRN PORTIONS OF THE CWA UNTIL LATE TUESDAY MORNING...AND THEN
SPREADING EWD ACROSS THE CWA THROUGH THE DAY. THE STRONGEST SFC AND
UPPER LEVEL FORCING WILL NOT BE IN PLACE UNTIL TUESDAY NIGHT. WHILE
THERE WILL AN INCREASE IN LOW LEVEL MOISTURE AS THE GULF OF MEXICO
OPENS UP IN ADVANCE OF THE SFC LOW...HAVE SOME CONCERN ABOUT THE
THUNDER POTENTIAL WITH THE SYSTEM. FOR ONE THING...THE BEST FORCING
WILL NOT BE IN PLACE UNTIL THE EVENING HOURS AND THE CWA WILL BE
NORTH OF THE ASSOCIATED WARM FRONT. SOME MODEST ISENTROPIC LIFT AND
MODEST ELEVATED INSTABILITY SHOULD BE IN PLACE...BUT GIVEN THE
EXPECTED TRACK OF THE SFC LOW THROUGH THE UPPER MISSISSIPPI VALLEY
AND WISCONSIN...AT THIS POINT...IT DOES NOT LOOK LIKE THE CWA WILL
EVER BE IN A WARM SECTOR ENVIRONMENT. SO...WILL KEEP THE CHANCE
THUNDER IN THE FORECAST FOR TUESDAY EVENING...BUT HAVE TRIMMED BACK
THE TS POTENTIAL FOR THE OVERNIGHT HOURS AS THE COLD FRONT CROSSES
THE AREA AT AN UNFAVORABLE TIME AND THEN A MID LEVEL DRY SLOT PUSHES
IN VERY QUICKLY FOLLOWING THE FROPA. THERE SHOULD BE A BREAK IN THE
PCPN BY WEDNESDAY MORNING AS THE DRY SLOT MOVES OVERHEAD...BUT AS
THE SFC LOW MOVES OFF TO THE EAST...THERE WILL BE A CHANCE OF SOME
LIGHT SNOW OR A RAIN/SNOW MIX ON THE BACKSIDE OF THE EXITING SYSTEM
FOR WEDNESDAY AFTERNOON AND EVENING.
FOR THE LONGER TERM FORECAST PERIOD...FROM THURSDAY THROUGH
SUNDAY...THE MEDIUM RANGE GUIDANCE IS RELATIVELY CONSISTENT IN
INDICATING A FAIRLY PROGRESSIVE PATTERN WITH INCREASING AMPLITUDE.
THE STORM TRACK SHOULD BE A SERIES OF PACIFIC ORIGIN SYSTEMS WITH NO
SIGNIFICANT ARCTIC INFLUENCE. THE TREND THROUGH THE LONGER TERM
WILL BE FOR ABOVE NORMAL TEMPERATURES THROUGH FRIDAY WITH PERIODIC
LOW PCPN CHANCES. THE STRONGEST UPPER LEVEL LOW IS ADVERTISED TO
CROSS THE UPPER MIDWEST BY NEXT WEEKEND...WHICH SHOULD BRING COOLER
CONDITIONS AND PERHAPS A CHANCE FOR SOME LIGHT SNOW...ESPECIALLY FOR
THE NORTHERN PORTIONS OF THE CWA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* LIGHT SW-WSW WIND BECOMING W WITH SPORADIC GUSTS 15-20 KTS
DURING PREDAWN...THEN BECOMING GUSTY 20-25 KTS AFTER SUNRISE
BEFORE DIMINISHING STEADILY IN THE AFTERNOON.
* LOW PROBABILITY FOR A BRIEF FEW HOUR PERIOD OF A BROKEN HIGH MVR
CEILING IN THE 2500-3000 FT AGL RANGE MID-MORNING TO MIDDAY
MONDAY.
TRS
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER FAR NORTHWEST WISCONSIN LATE THIS EVENING...WITH
SURGING COLD FRONT ARCING SOUTH THROUGH LAKE MICHIGAN TO ABOUT
THE IL/IN STATE LINE AT 05Z. WINDS HAVE SHIFTED WEST BEHIND THE
FRONT...THOUGH DIRECTION DOES VARY A BIT 260-280 DEGREES. MODEST
BUT NOTICEABLE PRESSURE RISE BUBBLE SPREADING ACROSS NORTHERN IL
MAY ALLOW SITES TO GUST A LITTLE SPORADICALLY PRIOR TO SUNRISE.
AFTER SUNRISE...DEEPENING OF LOW LEVEL MIXED LAYER AND STRONGER
PUSH OF COLD ADVECTION SHOULD ALLOW MORE UNIFORMLY GUSTY WEST
WINDS WITH GUSTS AROUND 25 KTS DURING THE MORNING. SURFACE LOW
MOVES OFF INTO SOUTHERN ONTARIO BY EARLY AFTERNOON...AND SPRAWLING
AREA OF HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH THE EVENING
WHICH WILL ALLOW WINDS TO DECREASE STEADILY DURING THE AFTERNOON
HOURS. THE SURFACE HIGH PRESSURE RIDGE WILL MOVE ACROSS THE
TERMINALS DURING THE LATE EVENING/OVERNIGHT HOURS...WITH WINDS
LIKELY BECOMING LIGHT/VARIABLE AFTER SUNSET.
WITH FAIRLY DRY MID/LOW LEVELS...ONLY SOME PATCHY SPARSE VFR
MID/HIGH CLOUD TO CONTEND WITH OVERNIGHT. WITH STEEPENING OF LOW
LEVEL LAPSE RATES AFTER SUNRISE MONDAY THERE WILL LIKELY BE SOME
FLAT STRATOCU DEVELOPMENT WITH BASES IN THE 2000-3000 FT AGL
RANGE. THERE IS SOME POTENTIAL THAT THIS WOULD DEVELOP BRIEFLY
INTO AN MVFR CEILING IN THE 2500-3000 FT RANGE LATE MORNING...
THOUGH CONFIDENCE IS LOW ENOUGH AND THE CEILING WOULD LIKELY LAST
A SHORT ENOUGH TIME TO LEAVE IT OUT OF THE TAFS AT THIS TIME. ANY
CU/STRATOCU WOULD LIKELY CLEAR OUT BY MID AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN WIND TRENDS...THOUGH MODERATE CONFIDENCE IN
SPORADIC GUST SPEEDS PRIOR TO SUNRISE.
* HIGH CONFIDENCE IN PREVAILING VFR CONDITIONS THROUGH PERIOD.
* LOW CONFIDENCE IN BRIEF PERIOD OF MVFR 2500-3000 FT BROKEN
STRATOCU DECK MID-MORNING/MIDDAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...CHANCE OF RAIN/SNOW CHANGING TO RAIN BY AFTERNOON. MVFR
POSSIBLE. MORE RAIN AND POSSIBLY A THUNDERSTORM TUESDAY NIGHT.
WEDNESDAY...CHANCE OF RAIN/SNOW WEDNESDAY AFTERNOON THEN A CHANCE
OF SNOW SHOWERS WEDNESDAY NIGHT. MVFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...CHANCE OF RAIN/SNOW...MVFR POSSIBLE.
SATURDAY...CHANCE OF LIGHT SNOW...MVFR POSSIBLE.
RATZER
&&
.MARINE...
320 PM CST
WINDS HAVE STRUGGLED TO STRENGTHEN TO GALES TODAY...WITH ONLY A FEW
GALES REPORTED ALONG THE SOUTHERN END OF LAKE MICHIGAN. WILL
CONTINUE THE GALE WARNING AS PLANNED...AND EVEN EXTEND IT BY AN
HOUR. WINDS WILL STAY STRONG AS THE LOW PASSES OVER THE UPPER
PENINSULA OF MICHIGAN TONIGHT...AND THEN DIMINISH BEHIND THE LOW.
WINDS WILL ALSO SHIFT FROM SOUTH TO WEST BEHIND THE COLD FRONT THAT
PASSES OVER THE LAKE AROUND MIDNIGHT.
HIGH PRESSURE MOVES INTO THE NORTHERN GREAT PLAINS MONDAY AFTERNOON
AND MOVES OVER LAKE MICHIGAN MONDAY NIGHT. WINDS VEER FROM
NORTHWEST TO SOUTHEAST AS THE LOW PASSES OVER THE LAKE AND REMAIN
LIGHT THROUGH EARLY TUESDAY MORNING. THE NEXT CHANCE OF GALES
ARRIVES AHEAD OF THE NEXT LOW PRESSURE SYSTEM LATE TUESDAY EVENING.
WINDS BECOME SOUTHWEST AND WEAKEN AS THE LOW PASSES OVER LAKE
MICHIGAN ON WEDNESDAY. MODELS INDICATE EITHER THE LOW WILL
STRENGTHEN SLIGHTLY AS IS MOVES OVERHEAD OR IT WILL ACT LIKE THE
SYSTEM TODAY AND WEAKEN. ALSO KEPT WINDS LOWER THAN GUIDANCE
BECAUSE WARM AIR ADVECTION AHEAD OF THE LOW MAY CREATE A STABLE
LAYER OVER THE LAKE. HOWEVER DUE TO THE INCONSISTENCIES IN MODEL
SOLUTIONS...KEPT WINDS AT LOW GALES.
IN EXTENDED LAND...ANOTHER LOW PRESSURE SYSTEM ARRIVES FROM THE
SOUTHWEST LATE ON FRIDAY. MODELS ARE INCONSISTENT WITH THIS
SYSTEM...THEREFORE WHILE GALES ARE POSSIBLE WITH THIS LOW...KEPT
WINDS AT SUB GALES FOR NOW.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1057 PM CST SUN FEB 26 2012
.DISCUSSION...
916 PM CST
SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST WITH A SOMEWHAT
DIFFUSE YET MARKED COLD FRONT NOW MOVING EAST ACROSS THE FORECAST
AREA. WINDS HAD DIMINISHED AHEAD OF THE FRONT WITH LESS MIXING
AFTER SUNDOWN...BUT BEHIND THE FRONT THE WEST NORTHWEST WINDS ARE
AGAIN GUSTING UPSTREAM...INCLUDING EVEN A FEW 25 TO 30 KT GUSTS IN
NORTHEAST IA AND SOUTHWEST WI. NAM AND RUC SOUNDINGS BOTH DO NOT
ADVERTISE THERMAL PROFILES TO HAVE THESE BROUGHT DOWN IN THE
FORECAST AREA BUT BELIEVE BOTH MODELS MAY NOT BE ADEQUATELY
ANALYZING THE COLD AIR ADVECTION PROFILES WITH THE FRONTAL
PASSAGE. SO OCCASIONAL GUSTS BEING QUITE A WAYS HIGHER THAN
GUIDANCE ADVERTISES ARE POSSIBLE THROUGH THE REST OF TONIGHT AFTER
THE FRONT.
A STRONG 130 KT JET SEEN ON WATER VAPOR AND UPPER AIR ANALYSIS IS
DIRECTLY NORTH OF THE AREA OFFERING SOME FAVORABLE BROAD QG FOR
WEAK ASCENT OVER THE AREA. THE MID TO UPPER LEVELS APPEAR TO BE
MOISTENING ON SATELLITE CHANNELS AND STARTING TO SEE THE FIRST
CLOUD OBSERVATIONS AROUND 8K TO 12K FT. THE RUC SEEMS TO HAVE A
GOOD HANDLE ON THE EVOLUTION GIVEN THE PATTERN...AND EXPECT
CLOUDS TO DEVELOP OVER THE SOUTHEAST FORECAST AREA THROUGH EARLY
OVERNIGHT AND SLOWLY SHIFT EAST.
THE CLOUDS AND WIND FIELD AND ASSOCIATED ADVECTION ARE OF COURSE
DIRECTLY IMPACTING THE TEMPERATURES WHICH HAVE BEEN SOMEWHAT
ERRATICALLY DROPPING...EVEN CLIMBING SLIGHTLY AS MIXING RE-ENSUES
BEFORE DROPPING WITHIN THE APPARENT COLD AIR ADVECTION. HAVE DONE
BEST AS ABLE TO ADJUST HOURLY TRENDS...BUT ALL IN ALL GOING
MINIMUM TEMPERATURE FORECAST STILL LOOKS VERY REASONABLE.
//PREV DISCUSSION...
320 PM CST
FOR THE REMAINDER OF THE AFTERNOON AND EVENING...THE MAIN CONCERN
WILL CONTINUE TO FOCUS ON WINDS. WILL LET THE WIND ADVISORY RIDE
UNTIL EXPIRATION. THE ONLY SITE TO REMAIN NEAR ADVISORY CRITERIA IS
PONTIAC WITH GUSTS TO 35KT/40MPH AT 20Z WITH HIGHER GUSTS OBSERVED
FARTHER SOUTH. SINCE THERE WILL STILL BE A COUPLE MORE HOURS WITH
STRONG GUST POTENTIAL...WILL LET THE ADVISORY RIDE RATHER THAN
CANCEL EARLY. OTHERWISE...THE FORECAST IS GENERALLY ON TRACK WITH
MILD CONDITIONS OVER THE REGION. TEMPERATURES OVER THE NORTHWESTERN
PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA...REMAIN A BIT
COOLER THAT THE REST OF THE AREA DUE TO THE RESIDUAL SNOW COVER.
HOWEVER...STRONG WARM ADVECTION AHEAD OF THE STRONG LOW PRESSURE
SYSTEM APPROACHING THE UPPER MISSISSIPPI VALLEY HAS ALLOWED
TEMPERATURES TO REACH WELL INTO THE 50S ELSEWHERE. EXPECT WINDS TO
BEGIN TO DROP OFF EARLY THIS EVENING AS THE FRONTAL TROUGH CROSSES
THE MISSISSIPPI RIVER...RELAXING THE PRESSURE GRADIENT. STILL
EXPECT A WEAK COLD FRONT TO PUSH SEWD THROUGH THE CWA OVERNIGHT
TONIGHT. GIVEN GENERALLY DRY CONDITIONS IN PLACE...DO NOT EXPECT
ANY PCPN WITH THE FROPA...AND ACTUALLY ONLY SOME INCREASING CLOUD
COVER OVER NWRN IL WITH SOME BACKWASH CLOUD WRAPPING AROUND THE SWRN
PERIPHERY OF THE LOW. COOLER AIR AND HIGH PRESSURE WILL BUILD IN
BEHIND THE EXITING LOW AND TEMPS OVERNIGHT TONIGHT SHOULD DROP INTO
THE MIDDLE 20S ALG AND WEST OF THE I-39 CORRIDOR AND THE THE UPPER
20S TO LOWER 30S ELSEWHERE.
FOR THE SHORT TERM FORECAST PERIOD...FROM MONDAY THROUGH
WEDNESDAY...THE PERIOD WILL START OUT QUIET ON MONDAY AS HIGH
PRESSURE PASSES THROUGH THE UPPER MIDWEST AND GREAT LAKES REGIONS.
SKIES WILL GENERALLY BE MOSTLY SUNNY...THOUGH TEMPERATURES WILL BE
NEAR OR SLIGHTLY BELOW NORMAL...RANGING FROM THE UPPER 30S NORTH OF
I-80 AND THE LOWER 40S TO THE SOUTH AND LOWS TUESDAY MORNING WILL
DROP INTO THE 20S. THE NEXT CHANCE FOR PCPN WILL COME ON TUESDAY AS
THE STRONG PACIFIC SYSTEM LIFTS OUT OF THE CENTRAL ROCKIES AND
ACROSS THE UPPER MISSISSIPPI VALLEY. THE LATEST MODEL TRENDS
CONTINUE TO SLOW DOWN THE PROGRESS OF THE SYSTEM SLIGHTLY...WITH THE
MODELS IN GENERALLY GOOD AGREEMENT ON NOT INTRODUCING PCPN INTO THE
WRN PORTIONS OF THE CWA UNTIL LATE TUESDAY MORNING...AND THEN
SPREADING EWD ACROSS THE CWA THROUGH THE DAY. THE STRONGEST SFC AND
UPPER LEVEL FORCING WILL NOT BE IN PLACE UNTIL TUESDAY NIGHT. WHILE
THERE WILL AN INCREASE IN LOW LEVEL MOISTURE AS THE GULF OF MEXICO
OPENS UP IN ADVANCE OF THE SFC LOW...HAVE SOME CONCERN ABOUT THE
THUNDER POTENTIAL WITH THE SYSTEM. FOR ONE THING...THE BEST FORCING
WILL NOT BE IN PLACE UNTIL THE EVENING HOURS AND THE CWA WILL BE
NORTH OF THE ASSOCIATED WARM FRONT. SOME MODEST ISENTROPIC LIFT AND
MODEST ELEVATED INSTABILITY SHOULD BE IN PLACE...BUT GIVEN THE
EXPECTED TRACK OF THE SFC LOW THROUGH THE UPPER MISSISSIPPI VALLEY
AND WISCONSIN...AT THIS POINT...IT DOES NOT LOOK LIKE THE CWA WILL
EVER BE IN A WARM SECTOR ENVIRONMENT. SO...WILL KEEP THE CHANCE
THUNDER IN THE FORECAST FOR TUESDAY EVENING...BUT HAVE TRIMMED BACK
THE TS POTENTIAL FOR THE OVERNIGHT HOURS AS THE COLD FRONT CROSSES
THE AREA AT AN UNFAVORABLE TIME AND THEN A MID LEVEL DRY SLOT PUSHES
IN VERY QUICKLY FOLLOWING THE FROPA. THERE SHOULD BE A BREAK IN THE
PCPN BY WEDNESDAY MORNING AS THE DRY SLOT MOVES OVERHEAD...BUT AS
THE SFC LOW MOVES OFF TO THE EAST...THERE WILL BE A CHANCE OF SOME
LIGHT SNOW OR A RAIN/SNOW MIX ON THE BACKSIDE OF THE EXITING SYSTEM
FOR WEDNESDAY AFTERNOON AND EVENING.
FOR THE LONGER TERM FORECAST PERIOD...FROM THURSDAY THROUGH
SUNDAY...THE MEDIUM RANGE GUIDANCE IS RELATIVELY CONSISTENT IN
INDICATING A FAIRLY PROGRESSIVE PATTERN WITH INCREASING AMPLITUDE.
THE STORM TRACK SHOULD BE A SERIES OF PACIFIC ORIGIN SYSTEMS WITH NO
SIGNIFICANT ARCTIC INFLUENCE. THE TREND THROUGH THE LONGER TERM
WILL BE FOR ABOVE NORMAL TEMPERATURES THROUGH FRIDAY WITH PERIODIC
LOW PCPN CHANCES. THE STRONGEST UPPER LEVEL LOW IS ADVERTISED TO
CROSS THE UPPER MIDWEST BY NEXT WEEKEND...WHICH SHOULD BRING COOLER
CONDITIONS AND PERHAPS A CHANCE FOR SOME LIGHT SNOW...ESPECIALLY FOR
THE NORTHERN PORTIONS OF THE CWA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WEST WINDS...SPORADIC GUSTS 15-20 KTS POSSIBLE OVERNIGHT
BECOMING MORE GUSTY 20-25 KTS AFTER SUNRISE BEFORE DIMINISHING
STEADILY IN THE AFTERNOON.
* LOW PROBABILITY FOR A BRIEF FEW HOUR PERIOD OF A BROKEN HIGH MVR
CEILING IN THE 2500-3000 FT AGL RANGE MID-MORNING TO MIDDAY
MONDAY.
RATZER
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER FAR NORTHWEST WISCONSIN LATE THIS EVENING...WITH
SURGING COLD FRONT ARCING SOUTH THROUGH LAKE MICHIGAN TO ABOUT
THE IL/IN STATE LINE AT 05Z. WINDS HAVE SHIFTED WEST BEHIND THE
FRONT...THOUGH DIRECTION DOES VARY A BIT 260-280 DEGREES. MODEST
BUT NOTICEABLE PRESSURE RISE BUBBLE SPREADING ACROSS NORTHERN IL
MAY ALLOW SITES TO GUST A LITTLE SPORADICALLY PRIOR TO SUNRISE.
AFTER SUNRISE...DEEPENING OF LOW LEVEL MIXED LAYER AND STRONGER
PUSH OF COLD ADVECTION SHOULD ALLOW MORE UNIFORMLY GUSTY WEST
WINDS WITH GUSTS AROUND 25 KTS DURING THE MORNING. SURFACE LOW
MOVES OFF INTO SOUTHERN ONTARIO BY EARLY AFTERNOON...AND SPRAWLING
AREA OF HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH THE EVENING
WHICH WILL ALLOW WINDS TO DECREASE STEADILY DURING THE AFTERNOON
HOURS. THE SURFACE HIGH PRESSURE RIDGE WILL MOVE ACROSS THE
TERMINALS DURING THE LATE EVENING/OVERNIGHT HOURS...WITH WINDS
LIKELY BECOMING LIGHT/VARIABLE AFTER SUNSET.
WITH FAIRLY DRY MID/LOW LEVELS...ONLY SOME PATCHY SPARSE VFR
MID/HIGH CLOUD TO CONTEND WITH OVERNIGHT. WITH STEEPENING OF LOW
LEVEL LAPSE RATES AFTER SUNRISE MONDAY THERE WILL LIKELY BE SOME
FLAT STRATOCU DEVELOPMENT WITH BASES IN THE 2000-3000 FT AGL
RANGE. THERE IS SOME POTENTIAL THAT THIS WOULD DEVELOP BRIEFLY
INTO AN MVFR CEILING IN THE 2500-3000 FT RANGE LATE MORNING...
THOUGH CONFIDENCE IS LOW ENOUGH AND THE CEILING WOULD LIKELY LAST
A SHORT ENOUGH TIME TO LEAVE IT OUT OF THE TAFS AT THIS TIME. ANY
CU/STRATOCU WOULD LIKELY CLEAR OUT BY MID AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN OVERALL WIND TREND...THOUGH LOW CONFIDENCE IN
SPORADIC GUST SPEEDS PRIOR TO SUNRISE.
* HIGH CONFIDENCE IN PREVAILING VFR CONDITIONS THROUGH PERIOD.
* LOW CONFIDENCE IN BRIEF PERIOD OF MVFR 2500-3000 FT BROKEN
STRATOCU DECK MONDAY MID-MORNING/MIDDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...CHANCE OF RAIN/SNOW CHANGING TO RAIN BY AFTERNOON. MVFR
POSSIBLE. MORE RAIN AND POSSIBLY A THUNDERSTORM TUESDAY NIGHT.
WEDNESDAY...CHANCE OF RAIN/SNOW WEDNESDAY AFTERNOON THEN A CHANCE
OF SNOW SHOWERS WEDNESDAY NIGHT. MVFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...CHANCE OF RAIN/SNOW...MVFR POSSIBLE.
SATURDAY...CHANCE OF LIGHT SNOW...MVFR POSSIBLE.
RATZER
&&
.MARINE...
320 PM CST
WINDS HAVE STRUGGLED TO STRENGTHEN TO GALES TODAY...WITH ONLY A FEW
GALES REPORTED ALONG THE SOUTHERN END OF LAKE MICHIGAN. WILL
CONTINUE THE GALE WARNING AS PLANNED...AND EVEN EXTEND IT BY AN
HOUR. WINDS WILL STAY STRONG AS THE LOW PASSES OVER THE UPPER
PENINSULA OF MICHIGAN TONIGHT...AND THEN DIMINISH BEHIND THE LOW.
WINDS WILL ALSO SHIFT FROM SOUTH TO WEST BEHIND THE COLD FRONT THAT
PASSES OVER THE LAKE AROUND MIDNIGHT.
HIGH PRESSURE MOVES INTO THE NORTHERN GREAT PLAINS MONDAY AFTERNOON
AND MOVES OVER LAKE MICHIGAN MONDAY NIGHT. WINDS VEER FROM
NORTHWEST TO SOUTHEAST AS THE LOW PASSES OVER THE LAKE AND REMAIN
LIGHT THROUGH EARLY TUESDAY MORNING. THE NEXT CHANCE OF GALES
ARRIVES AHEAD OF THE NEXT LOW PRESSURE SYSTEM LATE TUESDAY EVENING.
WINDS BECOME SOUTHWEST AND WEAKEN AS THE LOW PASSES OVER LAKE
MICHIGAN ON WEDNESDAY. MODELS INDICATE EITHER THE LOW WILL
STRENGTHEN SLIGHTLY AS IS MOVES OVERHEAD OR IT WILL ACT LIKE THE
SYSTEM TODAY AND WEAKEN. ALSO KEPT WINDS LOWER THAN GUIDANCE
BECAUSE WARM AIR ADVECTION AHEAD OF THE LOW MAY CREATE A STABLE
LAYER OVER THE LAKE. HOWEVER DUE TO THE INCONSISTENCIES IN MODEL
SOLUTIONS...KEPT WINDS AT LOW GALES.
IN EXTENDED LAND...ANOTHER LOW PRESSURE SYSTEM ARRIVES FROM THE
SOUTHWEST LATE ON FRIDAY. MODELS ARE INCONSISTENT WITH THIS
SYSTEM...THEREFORE WHILE GALES ARE POSSIBLE WITH THIS LOW...KEPT
WINDS AT SUB GALES FOR NOW.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
1137 PM CST SUN FEB 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST - TONIGHT AND MONDAY...
CLEAR SKIES AND W-NW DOWNSLOPE WINDS HAVE ALLOWED SURFACE
TEMPERATURES TO RISE INTO THE UPPER 50S TO MID 60S ACROSS MOST OF
NORTHEAST KANSAS. EXPECT THE WARM AND DRY CONDITIONS TO PERSIST FOR
THE REST OF THE AFTERNOON. SURFACE HIGH PRESSURE WILL BUILD INTO THE
NORTHERN PLAINS AND NOSE INTO THE FORECAST AREA BRINGING CLEAR SKIES
OVERNIGHT WITH CALM WINDS. DO NOT EXPECT MUCH IN THE WAY OF COLD AIR
ADVECTION...BUT RADIATIONAL COOLING WILL ALLOW THE BOUNDARY LAYER TO
COOL TO BELOW FREEZING.
EXPECT SOME COLD AIR ADVECTION TO TRICKLE INTO THE AREA BEHIND THE
VERY LIGHT NORTHERLY FLOW FOR MONDAY. MIXING NOT QUITE AS DEEP ON
MONDAY AS SUNDAY...SO THAT FACTOR IN COMBINATION WITH THE WEAK COLD
AIR ADVECTION WILL KEEP TEMPS ON MONDAY MORE SEASONAL. CLOUDS WILL
BE ON THE INCREASE BY MONDAY AFTERNOON/EVENING AS WARM/MOIST AIR
GETS ADVECTED NORTHWARD. CONDENSATION AS A RESULT OF THE ISENTROPIC
LIFT ASSOCIATED WITH THE WARM AIR ADVECTION WILL LIKELY BEGIN
SHORTLY AFTER NOON...WHICH WILL ALSO AID IN KEEPING TEMPERATURES
FROM RISING MUCH HIGHER THAN THE LOWER 50S.
JL
LEIGHTON
LONG TERM - MONDAY NIGHT THROUGH SUNDAY...
MONDAY NIGHT THROUGH TUESDAY NIGHT...
MODEL AGREEMENT IS NOW FAIRLY GOOD IN THE TRACK OF A POTENT
NEGATIVELY TILTED UPPER LEVEL TROUGH. THE SURFACE LOW WILL TRACK
WELL NORTH OF THE LOCAL FORECAST AREA WITH A SHARP FAST MOVING DRY
LINE CROSSING THE AREA BETWEEN 21Z TUESDAY AND 03Z WEDNESDAY.
WARM MOIST ADVECTION WILL TAKE PLACE ON MONDAY NIGHT AND TUESDAY
MORNING AHEAD OF THE SYSTEM WITH SHOWERS AND A FEW ELEVATED
THUNDERSTORMS EXPECTED TO DEVELOP AND MOVE INTO THE AREA MONDAY
NIGHT. THIS ACTIVITY SHOULD ALL REMAIN BELOW SEVERE LIMITS WITH
SOME LOW END POTENTIAL FOR SMALL HAIL THROUGH NOON ON TUESDAY.
WHILE CLOUD COVER WILL BE ABUNDANT THROUGH THE DAY ON TUESDAY...
TEMPERATURES WILL WARM NICELY WITH AMPLE WARM ADVECTION. THE CLOUD
LAYER WILL ALSO BE RELATIVELY SHALLOW AND LOW BY TUESDAY
AFTERNOON...AND A FEW BREAKS WILL BE POSSIBLE AHEAD OF THE DRY
LINE BY LATE AFTERNOON. SURFACE DEWPOINTS WILL CLIMB INTO THE MID
50S BY LATE TUESDAY ACROSS MUCH OF THE FORECAST AREA WITH TEMPS IN
THE UPPER 50S AND LOW 60S. EXPECT THE DRY LINE TO ENTER THE
FORECAST AREA SOMETIME BETWEEN 21Z AND 00Z...AND PUSH EAST INTO
MISSOURI ONLY 3 TO 4 HOURS LATER. CONVECTION IS EXPECTED TO
DEVELOP IMMEDIATELY ALONG THE DRY LINE BOUNDARY BY LATE AFTERNOON
AND CROSS THE FORECAST AREA...BUT SUBSTANTIAL UNCERTAINTY EXISTS
REGARDING THE POTENTIAL FOR STRONG TO SEVERE STORMS.
CURRENT INDICATIONS ARE THAT 200-500 J/KG OF SURFACE BASED CAPE
WILL BE PRESENT IN A NARROW BAND NEAR THE BOUNDARY. THOSE ARE
MEAGER VALUES BUT THE MAJORITY OF THIS INSTABILITY WILL BE IN THE
LOWEST 15000 FEET OF THE ATMOSPHERE WITH MAX LIFTED INDEX VALUES
IN THAT LAYER APPROACHING -5. THIS WOULD SUGGEST THE POTENTIAL FOR
SOME STRONGER SHALLOW UPDRAFTS. SHEAR THROUGH THE DEPTH OF THE
CONVECTIVE LAYER...ABOUT 0-4 KM...IS 50-60 KTS WHILE 0-1 KM SHEAR
IS 30-40 KTS. THESE VALUES ARE MORE THAN SUFFICIENT TO PRODUCE
ORGANIZED STORMS WITH SOME POTENTIAL FOR LOW TOPPED SUPERCELL
DEVELOPMENT. HOWEVER...THE UNIDIRECTIONAL NATURE OF THE SHEAR MAY
SUGGEST MORE OF A QUASI-LINEAR DEVELOPMENT WITH A BIT MORE
POTENTIAL FOR DAMAGING WINDS AT THE SURFACE. IT WILL BE DIFFICULT
TO GET LARGE HAIL WITH SUCH SHALLOW UPDRAFTS PERHAPS HAVING
TROUBLE CLIMBING ABOVE THE -20C LEVEL...BUT AT LEAST SMALL HAIL
WOULD REMAIN POSSIBLE. TORNADO POTENTIAL IS NON-ZERO...BUT HIGHLY
DEPENDENT UPON DEVELOPMENT OF MORE ROBUST UPDRAFTS...AND STRONG
UPDRAFT POTENTIAL IS THE MOST SIGNIFICANT UNCERTAINTY WITH THIS
FORECAST.
WEDNESDAY THROUGH SUNDAY...
WILL DRY OUT QUICKLY BEHIND THIS SYSTEM AND REMAIN DRY WITH A
SLIGHT COOL DOWN FOR WEDNESDAY AND A QUICK RECOVERY WITH WARM
TEMPS AGAIN ON THURSDAY. A WEAKER STORM SYSTEM WILL THEN CROSS THE
PLAINS THURSDAY NIGHT INTO FRIDAY. THIS SYSTEM DOES NOT HAVE A
PARTICULARLY STRONG PRECIP SIGNAL BUT APPEARS WORTHY OF AT LEAST A
SLIGHT CHANCE OF LIGHT RAIN WITH PERHAPS A MIX TO LIGHT SNOW
THURSDAY NIGHT. IT DOES NOT APPEAR TO BE A HIGH IMPACT EVENT AT
THIS TIME. EXPECT DRY CONDITIONS AND NEAR NORMAL TEMPERATURES FOR
SATURDAY AND SUNDAY.
BARJENBRUCH
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE TERMINAL FCST PERIOD
WITH ONLY SCT HIGH CLOUDS EXPECTED. WILL KEEP WINDS NORTH 6 TO 8 KTS
OVERNIGHT WITH SECOND PUSH OF COOLER AIR. WILL THEN GRADUALLY VEER
TO THE NORTHEAST 6-10KTS BEYOND 12Z...THEN EASTERLY AROUND 10 KTS
ON THE BACKSIDE OF RETREATING SFC HIGH. FOR NOW WILL ONLY INCLUDE
SCT CIRRUS UNTIL 12Z FOLLOWED BY BKN MID LEVEL DECK BY 00Z/28
AROUND 10 KFT...ALTHOUGH LOWER CIGS EXPECTED JUST BEYOND THE END
OF THIS FCST PERIOD.
&&
.FIRE WEATHER...
DEEP MIXING HAS COMMENCED ACROSS ALL OF NORTHEAST KANSAS BRINGING
VERY DRY LOW LEVEL AIR TO THE SURFACE. RUC SOUNDINGS INDICATE THAT
THE ATMOSPHERE HAS MIXED TO APPROXIMATELY 800 MB OR 5600 FEET. W-NW
WINDS AT THE SURFACE CONTAIN QUITE A BIT OF A DOWNSLOPE TRAJECTORY
WHICH HAS AIDED IN WARMING AND DRYING THE AIR. AS A RESULT RELATIVE
HUMIDITY VALUES HAVE DROPPED INTO THE MID TEENS THIS AFTERNOON...AND
WILL LIKELY REMAIN IN THE MIDDLE TEENS THROUGH AT LEAST SUNSET.
WINDS THROUGHOUT THE DAY HAVE BEEN RELATIVELY LIGHT AS OBSERVATIONS
HAVE INDICATED 10 TO 15 MPH W-NW WINDS. DUE TO THE DEEP MIXING SOME
WIND GUSTS OF UP TO 20-25 MPH ARE POSSIBLE...BUT THOSE GUSTS WILL BE
RATHER INFREQUENT. RH VALUES WILL START TO RISE ONCE SURFACE
TEMPERATURES BEGIN TO COOL RIGHT AROUND SUNSET.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
951 PM MST SUN FEB 26 2012
.UPDATE...
ISSUED AT 651 PM MST SUN FEB 26 2012
SFC HIGH NOW SETTLING OVER THE AREA AS WINDS HAVE RAPIDLY
DECREASED. 00Z SOUNDINGS INDICATE DRY AIR MASS IN PLACE AT DNR AND
TO A LESSER EXTENT DDC...WITH LOW LEVEL MIXING RATIOS NOTICEABLY
HIGHER AT KLBF. WITH THESE OBSERVATIONS AND EXPECTED WIND
FIELD...STILL EXPECT A FAIRLY SHARP NORTHEAST TO SOUTHWEST TD
GRADIENT THROUGH THE EVENING...ALTHOUGH THERE WILL BE SOME
RECOVERY WITH LOSS OF DEEP MIXING. WHILE THINGS WILL BE SLIGHTLY
MORE HUMID...MOISTURE PROFILES DO NOT LOOK DEEP ENOUGH TO PREVENT
TEMPS FROM DROPPING SHARPLY GIVEN LIGHT WINDS...DRY AIR AND
MINIMAL HIGH CLOUD COVER. HAVE LOWERED TEMPS 4-5 DEGREES AT
SEVERAL LOCATIONS...ESPECIALLY NORMAL COLD SPOTS LIKE WESTERN
CHEYENNE COUNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 236 PM MST SUN FEB 26 2012
LATEST VISIBLE SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOW AN
UPPER LEVEL TROUGH OVER THE NORTHERN CONUS WITH AN UPPER LEVEL
JET OVER NORTHWEST KANSAS AND SOUTHERN NEBRASKA. SURFACE
OBSERVATIONS REPORT NORTHWEST WINDS GUSTING 35 TO 45 MPH AS THE
STRONGER WINDS ABOVE THE SURFACE MIX DOWN.
THE STRONG WINDS THAT PLAGUED THE NORTHERN PORTIONS OF THE TRI-STATE
AREA WILL COME TO AN END AROUND SUNSET AS TEMPERATURES COOL. DURING
THE NIGHT A SURFACE HIGH PRESSURE WILL MOVE EAST THROUGH
NEBRASKA...CAUSING THE WINDS TO SWING TO THE NORTH. DURING THE
OVERNIGHT HOURS ISENTROPIC ANALYSIS AND RELATIVE HUMIDITY PLOTS
SHOW SOME LIFT AND SATURATED AIR MOVING INTO THE AREA FROM THE
SOUTH...WHICH WILL LEAD INCREASED CLOUD COVER FROM NORTH TO SOUTH.
WITH DRIER AIR IN PLACE AND LIGHT WINDS...TEMPERATURES WILL BE
COOLER THAN LAST NIGHT...RANGING FROM THE UPPER TEENS IN SOUTHWEST
NEBRASKA TO THE LOWER 20S IN WEST CENTRAL KANSAS.
MONDAY THROUGH MONDAY NIGHT...UPPER LOW WILL BE OVER PACIFIC COAST
EARLY MONDAY MORNING...AND WILL STILL BE OVER GREAT BASIN EARLY
MONDAY EVENING. OVERALL TREND WITH GUIDANCE HAS BEEN TO SLOW DOWN
THIS FEATURE. WHILE THERE IS DECENT H7-H5 MOISTURE IN PLACE
BY 18Z MONDAY...WITH LIMITED LIFT AND DRY LAYER BELOW H7...I
DECIDED AGAINST MENTION OF SPRINKLES MONDAY AFTERNOON. I ADJUSTED
TIMING TO KEEP FORECAST DRY THROUGH 03Z...AND TO LIMIT BEST
CHANCES IN THE FAR EASTERN PART OF THE CWA...TRIMMING POPS IN THE
WEST. WAA OVERNIGHT MONDAY WILL RESULT IN TEMPS INCREASING
AFTER MIDNIGHT...WITH LOWS LIKELY LATE MONDAY EVENING. AS A RESULT
PRECIP SHOULD MAINLY FALL AS RAIN...THOUGH A BRIEF RAIN/SNOW MIX
COULDNT BE RULED OUT IN EASTERN COLORADO. WHILE WINDY CONDITIONS
ARE EXPECTED MONDAY...LIMITED MIXING DUE TO CLOUD COVER SHOULD
KEEP CONDITIONS BELOW ADVISORY LEVELS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 236 PM MST SUN FEB 26 2012
TUESDAY...THE UPPER LOW WILL DEEPEN AS IT MOVES OUT OF THE
INTER-MOUNTAIN WEST TOWARDS THE NEBRASKA PANHANDLE BY MIDDAY TUESDAY.
GUIDANCE HAS COME IN GOOD AGREEMENT WITH A NORTHERN TRACK...SPEEDING
UP THE EASTWARD THE UPPER LOW. THIS RESULTS IN A DRY SLOT QUICKLY
PROGRESSING NORTH OVER THE CWA BY 18Z. I ADJUSTED POPS ACCORDINGLY
WITH HIGHEST POPS TUESDAY MORNING...AND THEN DECREASING IN COVERAGE
TUESDAY AFTERNOON. I LEFT ISOLATED THUNDERSTORMS IN FORECAST WITH
GUIDANCE STILL SHOWING INSTABILITY AXIS ACROSS EASTERN HALF OF CWA.
STRONG WINDS ALOFT WILL ALSO LEAD TO STRONG WINDS TUESDAY AS THE
SYSTEM MOVES THROUGH THE REGION...WHICH COULD RESULT IN WARNING
CRITERIA WINDS (GUSTS 60MPH OR GREATER).
WEDNESDAY THROUGH SUNDAY...SHORTWAVE RIDGE WILL BUILD IN THE REGION
WEDNESDAY AND THURSDAY...WITH DRY CONDITIONS AND MILD TEMPS
CONTINUING. A SHORTWAVE TROUGH IS STILL EXPECTED TO PASS OVER THE
REGION THURSDAY NIGHT. MEASURABLE PRECIP CANT BE RULED
OUT...SO SLIGHT CHANCE POPS WERE LEFT IN PLACE. THE REMAINDER OF
THE FORECAST PERIOD IS EXPECTED TO REMAIN DRY. SEASONAL HIGH
TEMPERATURES (MID/UPPER 40S) WILL RETURN FRIDAY AND
SATURDAY...WITH NW FLOW OVER THE CENTRAL HIGH PLAINS. RIDGE WILL
BEGIN TO DEEPEN SUNDAY ACROSS THE WESTERN US...WITH MILD
TEMPERATURES RETURNING TO THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 951 PM MST SUN FEB 26 2012
PREVAILING WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT...BECOMING
SOUTHEASTERLY AFTER SUNRISE. AS DAYTIME MIXING INCREASES...WINDS
WILL INCREASE AND BEGIN GUSTING...TAKING ON MORE OF A SOUTHERLY
COMPONENT BY MIDDAY. CEILINGS WILL DECREASE IN THE LATE AFTERNOON
INTO THE EVENING AHEAD OF AN UPPER LEVEL LOW...LOWERING INTO THE
MVFR RANGE BY LATE IN THE PERIOD. PRECIPITATION WILL ALSO BE
POSSIBLE LATE IN THE PERIOD...BUT CONFIDENCE IS TOO LOW AT THIS
TIME TO PLACE PRECIPITATION AT THE TERMINALS DURING THIS TAF
CYCLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...JTL/DR
LONG TERM....DR
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
952 PM EST TUE FEB 28 2012
.Update...
Update#2
Issued at 945 PM EST Feb 28 2012
A line of thunderstorms has developed across southeast MO and
southern IL. Timing of this line brings it into the western portion
of the forecast area around 05Z. Mesoscale models continue to
develop more convection overnight as the low level jet ramps up.
Have made only minor adjustments to the ongoing forecast.
Update#1
Issued at 630 PM EST Feb 28 2012
The latest runs of the HRRR and the Rapid Refresh are indicating a
bit later start to the precipitation this evening. Currently there
is nothing much on radar close to the forecast area. Will therefore
take out/lower pops before the 05-06Z time frame. Temperatures are
also running quite a bit warmer than hourlies so will update to
bring them in line. Updates will be out soon.
.Short Term (Tonight through Wednesday night)...
Updated at 200 PM EST Feb 28 2012
...Heavy rain/strong storms tonight with potential for severe storms
tomorrow...
The much anticipated storm system that will affect us in the short
term is currently developing over Nebraska, with it`s warm front and
60+ dewpoints slowly filtering northward across the southern CONUS,
and it`s cold front just downstream of the Rockies. Looks like with
the 12z runs of the mesoscale models, think precipitation will come
in two main waves. First, with the warm-air advection/elevated
showers/storms overnight ahead of the warm front. And second, along
of and just ahead of the cold front tomorrow afternoon.
Tonight, clouds and moisture will be on the increase tonight as the
surface low develops and moves towards the Upper Midwest overnight.
This will help draw the warm front from southwest to northeast
across our County Warning Area (CWA), mainly from the 07-13z time
frame. Showers and thunderstorms should develop along the nose of a
65-70 kt low-level jet, which will overspread north of and ahead of
the warm front from SW to NE across the CWA. However, best moisture
convergence seems to be across our northwest CWA after 06z, so think
convection will be rather scattered from 00-06z tonight, and will
blow up ahead of the warm front, mainly hugging the Ohio River and
into north-central Kentucky from 06-12z. At this time, our far
southwestern CWA could see surface-based warm-sector air, but not
sure any of the convection will be that far south to be rooted in
the boundary layer air. Thus, think the severe chances tonight are
fairly slim. However, if storms do lag into central and even
south-central KY in the morning (4-8am CST), these will likely be
surface-based, and a severe threat would be possible, with damaging
winds and possibly an isolated tornado threat but think that is slim
right now. These storms look more like heavy rainers, possibly
hailers, and ample lightning. And again, think the concentration
will mainly be across the central part of the CWA northward or
northwestward.
Then after daybreak, warm-air advection convection should more north
of the CWA, with the entire CWA getting rooted into the boundary
layer/warm-sector air. Not sure we`ll see a break in the low
strato-cu, but it is possible. If breaks occur, much of the
low-level jet winds will mix down, creating ample gusty winds
tomorrow. Think sustained winds of 20-25 mph will be possible with
gusts as high as 40 mph, close to wind advisory criteria. May defer
that to the next forecast tonight. Either way, we`ll be sectored in
the warm, moist, gusty air ahead of the quickly approaching cold
front. Progged soundings show ample deep-layer shear, and strong
speed shear in the low-levels. Deep moisture along the cold front
however will be much lower than the overnight moisture, so think a
few storms will erupt along the cold front, but not a large, thick
line of convection. However, any storm that develops along the cold
front has the potential to become quickly supercellular, with
damaging winds, hail and isolated tornadoes being potential threats.
Best chance for this would be east of I-65 after noon tomorrow.
There will still be a severe weather threat along the cold front
west of I-65 as well, but the best heating and longer time to
recover from morning convection will happen over the eastern CWA.
So overall, looks like the best chance for severe weather will be a
small window over our southwestern CWA after 4am CST late tonight,
but a better chance mainly along and east of I-65 tomorrow
afternoon. Behind the cold frontal passage, winds will veer around
to the west and continue to be gusty until Wednesday night where
they will taper off.
Lowered precipitation in the grids to account for the break between
late night/early morning warm frontal convection and the lesser
amount but more significant strong-severe convection tomorrow
midday-afternoon.
Concerning temps, lows will drop off early tonight and then increase
towards 12z with the warm front pushing northward. Tomorrow, despite
mostly cloudy conditions, temperatures will still be able to rise
into the 60s and even lower 70s over the south/southeast.
.Long Term (Thursday - Tuesday)...
Updated at 315 PM EST Feb 28 2012
...Potential for more strong to severe thunderstorms again Friday
afternoon and night...
Another potent storm system on Friday is the main concern in the
extended forecast. Before that occurs, however, Thursday will be a
tranquil weather day between systems. Surface high pressure over the
Ohio Valley and Southeast will ensure a mostly sunny day, and
temperatures will remain mild with afternoon highs generally in the
lower and mid 60s.
The high will move off to our east quickly Thursday night as a
deepening trough aloft takes shape over the western United States
and begins moving east. The trough will cause CYCLOGENESIS across
the southern high Plains Thursday night. The surface low pressure
center will then deepen quite rapidly as it moves northeast into the
mid
Mississippi Valley Friday and Great Lakes Friday night. Ahead of
this low, low-level moisture should return rapidly. Last night`s and
the newest 12z model runs suggest an area of precipitation will
quickly develop Thursday night over the Tennessee Valley in a warm
advection/isentropic lift zone. Elevated instability returning from
the southern Plains suggests that thunder will be embedded within
the area of rain. This precipitation may make it into south-central
KY by Friday morning, then lift quickly northeast into eastern KY in
the afternoon.
The main concern is Friday afternoon and evening, according to the
latest model timing. Wind fields increase throughout the lower and
mid levels, while actually decent instability is forecast to develop
in the warm sector between the departing warm front and east of a
potent cold front, which will extend south from the low pressure
center. Given cold frontal forcing, wind fields, and instability,
strong to severe storms could develop over parts of the Ohio Valley
extending south into the Tennessee Valley and lower Mississippi
Valley/southeastern United States. This system will need to be
watched closely.
Much cooler weather will move in for the weekend. The strong cyclone
mentioned above will move north of the Great lakes, with possibly a
surface pressure under 980mb. It parent 500mb trough will be
absorbed by a strengthening polar vortex near Hudson`s Bay. By early
Sunday, ridging will strengthen over the Rockies with troughing over
the Great Lakes. Expect a partly cloudy sky Saturday with brisk west
winds developing during the afternoon. Highs Saturday will remain in
the lower to mid 50s. A weak clipper will scoot southeast from the
Upper Missouri Valley Saturday and traverse the Commonwealth on
Sunday. Cloud cover will increase Sunday with just a slight chance
of showers. Highs Sunday will have a hard time reaching 50.
In a slowly progressive pattern, 500mb ridging will move east across
the central plains on Monday. After partly cloudy, cool day Monday
with high pressure nearly overhead, southwest winds will commence
Tuesday, beginning a warmup.
&&
.Aviation (00Z TAF Issuance)...
Updated at 612 PM EST Feb 28 2012
A storm system will approach and cross the area through this TAF
period. A warm front will move north across the state through this
evening. Overnight a low level jet will crank up. This will lead to
storm development across the area around 05-06Z, which will spread
east overnight. Have moved back the timing of precip starting at
SDF and BWG, as it looks to be closer to the 05-06Z time frame. Will
continue to mention LLWS from this time on as well as models show
winds around 50 knots out of the SSW at 2 kft.
There looks to be a possible lull in precipitation for a portion of
the morning hours ahead of the cold front. This front will cross the
area through the late morning and afternoon tomorrow. Storms will
redevelop along this front. Ahead of the front, winds will be gusty
out of the southwest through the day, with gusts as high as 30 knots
at times.
Ceilings and visibilities will be a challenge with the
precipitation. MVFR to IFR conditions will be possible with the
storms. Between the two batches of precipitation, skies should
improve for a bit, though there is some uncertainty as to if VFR
conditions will be possible.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AL
Long Term........JSD
Aviation.........EER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
636 PM EST TUE FEB 28 2012
.Update...
Issued at 630 PM EST Feb 28 2012
The latest runs of the HRRR and the Rapid Refresh are indicating a
bit later start to the precipitation this evening. Currently there
is nothing much on radar close to the forecast area. Will therefore
take out/lower pops before the 05-06Z time frame. Temperatures are
also running quite a bit warmer than hourlies so will update to
bring them in line. Updates will be out soon.
.Short Term (Tonight through Wednesday night)...
Updated at 200 PM EST Feb 28 2012
...Heavy rain/strong storms tonight with potential for severe storms
tomorrow...
The much anticipated storm system that will affect us in the short
term is currently developing over Nebraska, with it`s warm front and
60+ dewpoints slowly filtering northward across the southern CONUS,
and it`s cold front just downstream of the Rockies. Looks like with
the 12z runs of the mesoscale models, think precipitation will come
in two main waves. First, with the warm-air advection/elevated
showers/storms overnight ahead of the warm front. And second, along
of and just ahead of the cold front tomorrow afternoon.
Tonight, clouds and moisture will be on the increase tonight as the
surface low develops and moves towards the Upper Midwest overnight.
This will help draw the warm front from southwest to northeast
across our County Warning Area (CWA), mainly from the 07-13z time
frame. Showers and thunderstorms should develop along the nose of a
65-70 kt low-level jet, which will overspread north of and ahead of
the warm front from SW to NE across the CWA. However, best moisture
convergence seems to be across our northwest CWA after 06z, so think
convection will be rather scattered from 00-06z tonight, and will
blow up ahead of the warm front, mainly hugging the Ohio River and
into north-central Kentucky from 06-12z. At this time, our far
southwestern CWA could see surface-based warm-sector air, but not
sure any of the convection will be that far south to be rooted in
the boundary layer air. Thus, think the severe chances tonight are
fairly slim. However, if storms do lag into central and even
south-central KY in the morning (4-8am CST), these will likely be
surface-based, and a severe threat would be possible, with damaging
winds and possibly an isolated tornado threat but think that is slim
right now. These storms look more like heavy rainers, possibly
hailers, and ample lightning. And again, think the concentration
will mainly be across the central part of the CWA northward or
northwestward.
Then after daybreak, warm-air advection convection should more north
of the CWA, with the entire CWA getting rooted into the boundary
layer/warm-sector air. Not sure we`ll see a break in the low
strato-cu, but it is possible. If breaks occur, much of the
low-level jet winds will mix down, creating ample gusty winds
tomorrow. Think sustained winds of 20-25 mph will be possible with
gusts as high as 40 mph, close to wind advisory criteria. May defer
that to the next forecast tonight. Either way, we`ll be sectored in
the warm, moist, gusty air ahead of the quickly approaching cold
front. Progged soundings show ample deep-layer shear, and strong
speed shear in the low-levels. Deep moisture along the cold front
however will be much lower than the overnight moisture, so think a
few storms will erupt along the cold front, but not a large, thick
line of convection. However, any storm that develops along the cold
front has the potential to become quickly supercellular, with
damaging winds, hail and isolated tornadoes being potential threats.
Best chance for this would be east of I-65 after noon tomorrow.
There will still be a severe weather threat along the cold front
west of I-65 as well, but the best heating and longer time to
recover from morning convection will happen over the eastern CWA.
So overall, looks like the best chance for severe weather will be a
small window over our southwestern CWA after 4am CST late tonight,
but a better chance mainly along and east of I-65 tomorrow
afternoon. Behind the cold frontal passage, winds will veer around
to the west and continue to be gusty until Wednesday night where
they will taper off.
Lowered precipitation in the grids to account for the break between
late night/early morning warm frontal convection and the lesser
amount but more significant strong-severe convection tomorrow
midday-afternoon.
Concerning temps, lows will drop off early tonight and then increase
towards 12z with the warm front pushing northward. Tomorrow, despite
mostly cloudy conditions, temperatures will still be able to rise
into the 60s and even lower 70s over the south/southeast.
.Long Term (Thursday - Tuesday)...
Updated at 315 PM EST Feb 28 2012
...Potential for more strong to severe thunderstorms again Friday
afternoon and night...
Another potent storm system on Friday is the main concern in the
extended forecast. Before that occurs, however, Thursday will be a
tranquil weather day between systems. Surface high pressure over the
Ohio Valley and Southeast will ensure a mostly sunny day, and
temperatures will remain mild with afternoon highs generally in the
lower and mid 60s.
The high will move off to our east quickly Thursday night as a
deepening trough aloft takes shape over the western United States
and begins moving east. The trough will cause CYCLOGENESIS across
the southern high Plains Thursday night. The surface low pressure
center will then deepen quite rapidly as it moves northeast into the
mid
Mississippi Valley Friday and Great Lakes Friday night. Ahead of
this low, low-level moisture should return rapidly. Last night`s and
the newest 12z model runs suggest an area of precipitation will
quickly develop Thursday night over the Tennessee Valley in a warm
advection/isentropic lift zone. Elevated instability returning from
the southern Plains suggests that thunder will be embedded within
the area of rain. This precipitation may make it into south-central
KY by Friday morning, then lift quickly northeast into eastern KY in
the afternoon.
The main concern is Friday afternoon and evening, according to the
latest model timing. Wind fields increase throughout the lower and
mid levels, while actually decent instability is forecast to develop
in the warm sector between the departing warm front and east of a
potent cold front, which will extend south from the low pressure
center. Given cold frontal forcing, wind fields, and instability,
strong to severe storms could develop over parts of the Ohio Valley
extending south into the Tennessee Valley and lower Mississippi
Valley/southeastern United States. This system will need to be
watched closely.
Much cooler weather will move in for the weekend. The strong cyclone
mentioned above will move north of the Great lakes, with possibly a
surface pressure under 980mb. It parent 500mb trough will be
absorbed by a strengthening polar vortex near Hudson`s Bay. By early
Sunday, ridging will strengthen over the Rockies with troughing over
the Great Lakes. Expect a partly cloudy sky Saturday with brisk west
winds developing during the afternoon. Highs Saturday will remain in
the lower to mid 50s. A weak clipper will scoot southeast from the
Upper Missouri Valley Saturday and traverse the Commonwealth on
Sunday. Cloud cover will increase Sunday with just a slight chance
of showers. Highs Sunday will have a hard time reaching 50.
In a slowly progressive pattern, 500mb ridging will move east across
the central plains on Monday. After partly cloudy, cool day Monday
with high pressure nearly overhead, southwest winds will commence
Tuesday, beginning a warmup.
&&
.Aviation (00Z TAF Issuance)...
Updated at 612 PM EST Feb 28 2012
A storm system will approach and cross the area through this TAF
period. A warm front will move north across the state through this
evening. Overnight a low level jet will crank up. This will lead to
storm development across the area around 05-06Z, which will spread
east overnight. Have moved back the timing of precip starting at
SDF and BWG, as it looks to be closer to the 05-06Z time frame. Will
continue to mention LLWS from this time on as well as models show
winds around 50 knots out of the SSW at 2 kft.
There looks to be a possible lull in precipitation for a portion of
the morning hours ahead of the cold front. This front will cross the
area through the late morning and afternoon tomorrow. Storms will
redevelop along this front. Ahead of the front, winds will be gusty
out of the southwest through the day, with gusts as high as 30 knots
at times.
Ceilings and visibilities will be a challenge with the
precipitation. MVFR to IFR conditions will be possible with the
storms. Between the two batches of precipitation, skies should
improve for a bit, though there is some uncertainty as to if VFR
conditions will be possible.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AL
Long Term........JSD
Aviation.........EER
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1036 PM EST TUE FEB 28 2012
.UPDATE...
ISSUED AT 1035 PM EST TUE FEB 28 2012
HAVE UPGRADED SOME COUNTIES IN NORTHERN LOWER MICHIGAN TO A
WARNING.
LOW PRESSURE NOW ADVANCING THROUGH EASTERN IOWA AHEAD OF A VERY
VIGOROUS UPPER LEVEL SHORT WAVE EJECTING NORTHEASTWARD FROM THE
CENTRAL PLAINS. VERY STRONG PULSE OF WARM ADVECTION FORCING/MOISTURE
FEED STARTING TO TAP THE GULF LEADING TO TO A LARGE EXPANDING
SHIELD OF PRECIP FROM ILLINOIS UP ACROSS WISCONSIN/MINNESOTA AND
THE DAKOTAS. STRONG CONVECTION BREAKING OUT IN THE CENTRAL PLAINS.
PRETTY MUCH YOUR TYPICAL STRONG SPRING STORM.
ACROSS THE REGION...A PRETTY HEFTY BATCH OF SNOWFALL HAS ALREADY
BLOSSOMED OVER SRN/ERN WISCONSIN THIS EVENING AND ABOUT TO WORK
INTO THE SW PART OF THIS CWA. BUT THE STRONGEST FORCING IS YET TO
ARRIVE...
OVERNIGHT...LOW PRESSURE SYSTEM WILL OCCLUDE OVER THE
IOWA/MINNESOTA REGION OVER THE NEXT SEVERAL HOURS. AS THIS
OCCURS...VERY STRONG PULSE OF WARM ADVECTION FORCING AND
ASSOCIATED WING OF PRECIP WILL ADVANCE UP THROUGH LOWER MICHIGAN
OVERNIGHT AND UP INTO EASTERN UPPER MICHIGAN WEDNESDAY
MORNING...FOLLOWED BY A SHARP DRY PUNCH OF AIR WORKING THROUGH THE
CWA DURING THE AFTERNOON. PRETTY MUCH INLINE WITH PREVIOUS
FORECAST THINKING.
INITIALLY...WAS SKEPTICAL OF NAM/GFS QPF AMOUNTS APPROACHING ONE
INCH BY WEDNESDAY EVENING WITH THIS STORM...ESPECIALLY GIVEN THAT
BULK OF PRECIP WILL ONLY LAST AROUND 6 HOURS BEFORE TAPERING OFF
SHARPLY TO DRIZZLE/FREEZING DRIZZLE WITHIN THE DRY SLOT DURING THE
AFTERNOON HOURS. HOWEVER...MODEL N-S CROSS SECTIONS ACROSS LOWER
MICHIGAN HAVE CHANGED MY MIND. VERY IMPRESSIVE F-GEN DEVELOPS
ACROSS THE REGION WEDNESDAY MORNING WITHIN THE SHARPLY CYCLONIC
FLOW AND VERY STRONG WIND CORE THAT WORKS UP THROUGH THE REGION.
RESULTING OMEGA BULLSEYE IS IMPRESSIVE...MAXIMIZING IN THE DGZ
RIGHT UP ACROSS NRN LOWER MICHIGAN FOR A TIME WEDNESDAY MORNING.
TERRAIN AND A STRONG SE LOW LEVEL FLOW WILL LIKELY HELP THE CAUSE
OVER NE AND NORTH CENTRAL LOWER MICHIGAN AS WELL.
GIVEN THAT...AND A SLIGHTLY SLOWER TREND IN THE 00Z GUIDANCE SUGGESTING
MORE PRECIP OVER NRN LOWER MICHIGAN...HAVE EXPANDED WARNING DOWN
TWO TIER OF COUNTIES IN NRN LOWER MICHIGAN. HAVE TENTAVELY LEFT
OUT CHARLEVOIX/ANTRIM COUNTIES AS DOWNSLOPING SE FLOW MAY KEEP PRECIP
IN CHECK...WILL SEE. STILL NOT CONVINCED WE SEE AN INCH OF LIQUID
WITH THIS SYSTEM. BUT EVEN IF WE GET CLOSE...ACCUMULATIONS IN THE
4 TO 7 INCH RANGE CERTAINLY VERY POSSIBLE OVER PORTIONS OF NE
LOWER MICHIGAN.
PRECIP TYPE ISSUES REMAIN WITH THIS SYSTEM...AS ABOVE FREEZING
WARM NOSE SURGES UP INTO NRN LOWER MICHIGAN ON WEDNESDAY.
BUT...TIMING IS EVERYTHING...AND BULK OF PRECIP ACROSS THE CWA
WILL BE LARGELY OVER BEFORE THE WARM NOSE ARRIVES. SO AT THIS
POINT...AM NOT TOO CONCERNED ABOUT SIGNIFICANT ICING OR PRECIP
CHANGING TO RAIN...AT LEAST DURING THE HEAVIEST PART OF THE EVENT.
UPDATE ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 732 PM EST TUE FEB 28 2012
MAINLY VFR CIGS ACROSS NRN LOWER MICHIGAN THIS EVENING...SAVE FOR
A NARROW CORRIDOR OF LIGHT SNOW/MVFR CIGS MOVING THROUGH THE PLN
AREA. VFR CONDITIONS WILL HOLD THROUGH THIS EVENING BUT GIVE WAY
TO MVFR CIGS AT TVC/MBL OVERNIGHT AS INITIAL BATCH OF SNOW WORKS
INTO THE REGION.
BIGGEST SURGE OF SNOWFALL AND SOLID IFR CONDITIONS ARRIVE EARLY
WEDNESDAY MORNING...AS OCCLUDING LOW PRESSURE LIFTS INTO THE UPPER
MIDWEST AND ASSOCIATED FRONT ADVANCES INTO LOWER MICHIGAN. EXPECT
A 4 TO 6 HOUR WINDOW OF HEFTIER SNOWFALL AT THE TERMINAL SITES
WEDNESDAY MORNING...TAPERING OFF TO FLURRIES/DRIZZLE/FREEZING
DRIZZLE BY AFTERNOON AS SHARP DRY SLOT ADVANCES UP THROUGH THE
REGION.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST WEDNESDAY FOR
MIZ019>021-025>027-031>036-041-042.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ016>018-022>024-028>030.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY FROM 1 AM TO 11 PM EST WEDNESDAY FOR LHZ349.
GALE WARNING FROM 1 AM TO 11 PM EST WEDNESDAY FOR LHZ345>348.
LM...GALE WARNING FROM 1 AM TO 11 PM EST WEDNESDAY FOR LMZ341-342.
GALE WARNING FROM 1 AM TO 5 PM EST WEDNESDAY FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...BA
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
732 PM EST TUE FEB 28 2012
.UPDATE...
ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 732 PM EST TUE FEB 28 2012
MAINLY VFR CIGS ACROSS NRN LOWER MICHIGAN THIS EVENING...SAVE FOR
A NARROW CORRIDOR OF LIGHT SNOW/MVFR CIGS MOVING THROUGH THE PLN
AREA. VFR CONDITIONS WILL HOLD THROUGH THIS EVENING BUT GIVE WAY
TO MVFR CIGS AT TVC/MBL OVERNIGHT AS INITIAL BATCH OF SNOW WORKS
INTO THE REGION.
BIGGEST SURGE OF SNOWFALL AND SOLID IFR CONDITIONS ARRIVE EARLY
WEDNESDAY MORNING...AS OCCLUDING LOW PRESSURE LIFTS INTO THE UPPER
MIDWEST AND ASSOCIATED FRONT ADVANCES INTO LOWER MICHIGAN. EXPECT
A 4 TO 6 HOUR WINDOW OF HEFTIER SNOWFALL AT THE TERMINAL SITES
WEDNESDAY MORNING...TAPERING OFF TO FLURRIES/DRIZZLE/FREEZING
DRIZZLE BY AFTERNOON AS SHARP DRY SLOT ADVANCES UP THROUGH THE
REGION.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST WEDNESDAY FOR
MIZ019>036-041-042.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ008-015.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ016>018.
LH...SMALL CRAFT ADVISORY FROM 1 AM TO 11 PM EST WEDNESDAY FOR LHZ349.
GALE WARNING FROM 1 AM TO 11 PM EST WEDNESDAY FOR LHZ345>348.
LM...GALE WARNING FROM 1 AM TO 11 PM EST WEDNESDAY FOR LMZ341-342.
GALE WARNING FROM 1 AM TO 5 PM EST WEDNESDAY FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...BA
SYNOPSIS...TL
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
523 PM CST TUE FEB 28 2012
.DISCUSSION...
WHAT A DIFFERENCE ABOUT 125 MILES MAKES... WHICH IS ROUGHLY THE
DIFFERENCE IN WHERE THIS SYSTEM LOOKS TO BE TRACKING VS HOW IT
APPEARED TWO DAYS AGO. OVERALL... THIS MEANS THE FORECAST IS
PRETTY SIMILAR TO WHAT HAS BEEN EXPECTED... EXCEPT EVERYTHING HAS
BEEN SHIFTED BY ABOUT THAT DISTANCE NORTHWARD. THERE WILL BE SOME
ADDITIONAL CHANGES FORTHCOMING IN TERMS OF THE HEADLINES AND
SNOWFALL EXPECTATIONS... AS WELL AS THE NORTHWARD EXTENT OF MIXED
PRECIPITATION. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW OUR SYSTEM FINALLY BEGINNING TO EMERGE FROM THE
SOUTHERN ROCKIES... WITH THE SURFACE LOW LOCATED NEAR THE
INTERSECTION OF COLORADO... NEBRASKA... AND KANSAS. THE GUIDANCE
IS... FINALLY... IN EXCELLENT AGREEMENT ON THE TIMING AND MOVEMENT
OF THIS SYSTEM... TAKING THE SURFACE LOW NORTHEAST INTO SOUTHERN
MINNESOTA BY 12Z WEDNESDAY... THEN VERY NEAR THE TWIN CITIES BY
18Z... BEFORE MOVING OFF TO THE GREAT LAKES WEDNESDAY NIGHT. SOME
DIFFERENCES DO REMAIN IN THE GUIDANCE IN TERMS OF EXACTLY HOW WARM
THE ELEVATED WARM LAYER WILL GET... AS WELL AS THE NEAR SURFACE
TEMPERATURES AND NORTHWARD EXTENT OF THE WARMER TEMPERATURES.
OVERALL... IT NOW LOOKS LIKE WE SHOULD GET SOME DEGREE OF MIXED
PRECIPITATION OVER ALL BUT PERHAPS THE FAR NORTHERN PART OF THE
AREA FOR A TIME TONIGHT. THE SOUTHERN CWFA HAS ALREADY
TRANSITIONED TO SLEET OR RAIN... AND THIS WILL CONTINUE TO PUSH
NORTH THROUGH THE EVENING. BASED THE FORECAST DETAILS ON A BLEND
OF GFS... NAM... AND SREF GUIDANCE... BUT WITH A BIT OF WEIGHT ON
THE RUC DURING THE FIRST 12 HOURS. ALSO LIKE THE GENERAL LOOK OF
THE HRRR PRECIPITATION/REFLECTIVITY FIELDS THROUGH THIS EVENING...
SO TOOK THAT INTO ACCOUNT.
AS MENTIONED... EXPECT TO SEE THE MIXED PRECIPITATION PUSH NORTH
THROUGH THIS EVENING AS THE STRONG LOW LEVEL JET PERSIST AHEAD OF
THE SURFACE LOW. SUFFICIENTLY WARM TEMPERATURES AROUND 850-825MB
LOOK TO GET AS FAR NORTH AS KAXN... BRINGING SOME CHANCE OF AT
LEAST ICE PELLETS INTO THE FAR NORTHERN PART OF THE FORECAST AREA.
A BRIEF WINDOW OF FREEZING RAIN STILL SEEMS POSSIBLE DURING THE
TRANSITION FROM SLEET TO RAIN WHICH WILL OCCUR OVER THE CENTRAL
AND SOUTHERN PART OF THE CWFA... ALTHOUGH OBSERVATIONS AND
FORECAST PROFILES SUGGEST THAT ANY FZRA SHOULD BE SHORT-LIVED WITH
THINGS PRIMARILY GOING FROM SLEET TO RAIN OVER NEARLY THE SOUTHERN
HALF OF THE AREA BY EARLY THIS EVENING. AS THE SYSTEM OCCLUDES
LATER TONIGHT AND WEDNESDAY MORNING AND BEGINS DRIFTING EAST WE
SHOULD SEE THINGS COOL DOWN ONCE AGAIN... WITH THE WARM TONGUE
ERODING FROM 09Z-15Z... CHANGING THE PCPN ASSOCIATED THE UPPER
TROUGH BACK TO SNOW FOR THE DAY ON WEDNESDAY. PRIOR TO THEN... IT
STILL APPEARS THAT WE WILL HAVE HEAVY PCPN TONIGHT... FALLING AS
SNOW AND SLEET OVER THE NORTH... SLEET AND RAIN OVER THE
CENTRAL... AND RAIN OVER THE SOUTH. HOWEVER... THE SOUTHERN PART
OF THE AREA SHOULD ALSO SEE THE DRY SLOT WORK IN... WHICH WILL END
HEAVIER PCPN IN THAT AREA TONIGHT. THERE IS SOME POSSIBILITY FOR
SOME CONVECTION TO DEVELOP IN THE DRY WEDGE... MAINLY TO OUR
SOUTH... BUT SOME ISOLATED THUNDER COULD GET UP INTO THE SOUTHERN
PART OF THE CWFA THIS EVENING INTO THE OVERNIGHT HOURS. IN THE
NORTH... WHERE THE PERSISTENT MODERATE TO HEAVY PCPN IS EXPECTED
TO OCCUR... SIGNIFICANT SNOWFALL ACCUMULATIONS STILL APPEAR
LIKELY... ALTHOUGH THEY MAY BE TEMPERED TO SOME DEGREE BY MIXING
WITH SLEET. STRONG MID-LEVEL FRONTOGENESIS... AND COUPLING WITH
THE UPPER JET CIRCULATION... STILL APPEAR TO BE IN PLACE FOR A
TIME TONIGHT... ALONG WITH NEGATIVE EPV NEAR AND ABOVE THAT LAYER
OF FORCING. OVER THE SOUTHERN PART OF THE AREA... THAT INSTABILITY
IS UPRIGHT GIVEN NEGATIVE DIFFERENTIAL THETA-E WHICH WILL BE IN
PLACE... BUT AS YOU GO NORTH THINGS SUGGEST IT WOULD BE MORE
SYMMETRIC IN NATURE. THAT WOULD SUGGEST MORE OF A CELLULAR PCPN
LOOK ON THE SOUTH END OF THINGS AS THEY PUSH NORTH LATER
TONIGHT... WITH MORE IN THE WAY OF BANDING FARTHER NORTH.
PCPN WILL LINGER THROUGH MUCH OF THE DAY ON WEDNESDAY AS THE UPPER
TROUGH SLOWLY PUSHES ACROSS THE AREA AND ABUNDANT DEEP LAYER
MOISTURE PERSISTS. SOME MIXED PCPN MAY STILL BE POSSIBLE IN THE
MORNING OVER THE SOUTHEAST PORTION OF THE AREA... BUT BY LATE
MORNING ANY REMAINING PCPN SHOULD BE IN THE FORM OF SNOW... WITH
SOME ADDITIONAL ACCUMULATIONS STILL EXPECTED... PARTICULARLY OVER
THE NORTH CENTRAL AND NORTHEAST CWFA. VERY WEAK RIDGING LOOKS TO
WORK INTO THE AREA WEDNESDAY NIGHT... BRINGING AN END THE PCPN...
BUT A WEAK NORTHERN STREAM SHORTWAVE MAY BRING A CHANCE OF SNOW
BACK INTO THE NORTHERN CWFA ON THURSDAY. THE NEXT FEATURE OF ANY
CONCERN STILL LOOKS LIKE IT WILL BE MOVING NEAR THE AREA ON
FRIDAY... BUT THE LATEST GUIDANCE CONTINUES THE IDEA OF KEEPING
THAT SYSTEM OFF TO OUR SOUTHEAST. WITH THE AFOREMENTIONED NORTHERN
STREAM UPPER TROUGH STILL IN THE VICINITY THROUGH FRIDAY... AND
THE SOUTHERN WAVE PASSING BY TO OUR SOUTHEAST... DID CARRY SOME
LOW POPS OVER MUCH OF THE AREA ON FRIDAY... BUT AT THIS POINT IT
DOES NOT APPEAR IT WILL BE MUCH OF AN ISSUE FOR OUR AREA. THE
WEEKEND INTO EARLY NEXT WEEK LOOK TO BE MAINLY DRY... ALTHOUGH
THERE COULD BE SOME FLURRIES AROUND OVER THE WEEKEND WITH CYCLONIC
FLOW AND FAIRLY STEEP BOUNDARY LAYER LAPSE RATES IN PLACE. DIDN/T
INCLUDE MUCH IN THE WAY OF PCPN MENTION AT THIS POINT... BUT
WOULDN/T BE SURPRISED TO EVENTUALLY NEED TO INCLUDE SOME SNOW
SHOWERS AND/OR FLURRIES FOR SATURDAY INTO SUNDAY. THE START OF
NEXT WEEK SHOULD SEE A SIGNIFICANT WARM UP ACROSS THE AREA AS
HEIGHTS BUILD... AND 1000-500MB THICKNESS VALUES CLIMB WELL ABOVE
555DM. INCLUDED HIGHS OF NEAR 50 DEGREES BY TUESDAY... WHICH
CERTAINLY DOESN/T LOOK UNREASONABLE AT THIS POINT SHOULD THINGS
WARM AS SUGGESTED.
&&
.AVIATION.../00Z TAF ISSUANCE/
SIGNIFICANT IMPACTS IN THE AVIATION WX DEPARTMENT WITH A LARGE
AREA OF PRECIPITATION...MIXED WITH SLEET/RAIN MOVES N/NE ACROSS
MPX FA THIS EVENING.
SHORT TERM CONCERNS DEAL WITH CHG OVER TO -RA WHICH WILL LIKELY
HAPPEN AT MSP/RNH/EAU BY 2-4Z...WITH RWF ALREADY -RA. HOWEVER...AT
STC THERE COULD BE A TIME PERIOD WHERE HEAVY SLEET/SNOW WILL
OCCUR...POSSIBLY MIXING WITH FREEZING RAIN THIS EVENING. ALTHOUGH
MOST OF THE ROADWAYS ARE WET...ELEVATED OBJECTS IN SOUTHERN MN
HAVE BEEN FREEZING WHICH MAY ALLOW FOR SOME RUNWAYS TO ICE UP
DURING HIGHER INTENSITY OF PRECIPITATION. SOMETHING TO WATCH OVER
THE NEXT FEW HRS AS THE SUN HAS SET. AXN MAY GET SOME MIXED
PRECIPITATION LATE THIS EVENING...BUT WILL CONTINUE LIFR IN
SN...POSSIBLY +SN AT TIMES OVERNIGHT. WNDS WILL LIKELY CONTINUE
THRU 6Z FROM THE E/ESE AND INCREASE IN SPD. BUT AS THE SFC LOW
MOVES CLOSER...WNDS WILL DECREASE AT RWF/MSP/RNH...THEN VEER TO
THE SE/S THAN NW AS THE SFC LOW MOVES OVERHEAD. IFR CIGS SHOULD BE
THE RULE THRU MOST OF THE TAF PERIOD WITH OCCASIONALLY LIFR IN
PRECIPITATION.
MSP...PERIOD OF MODERATE -RA/SLEET/SNOW THRU 3Z ALONG WITH AN
OUTSIDE CHC OF -FZRA. AFT 3Z...PRECIPITATION SHOULD TAPER OFF A
BIT...BUT ANOTHER ROUND OF HEAVIER PRECIPITATION IS POSSIBLE
OVERNIGHT AS ANOTHER CONVECTIVE BAND FROM NEB...MOVES NE. TIMING
OF -SN SHOULD BE AFT 9Z...WITH A PERIOD OF MODERATE SN POSSIBLE
DURING THE MORNING BEFORE IT TAPERS OFF DURING THE AFTN. WNDS
WILL REMAIN FROM THE E/ESE TONIGHT AND INCREASE TOWARD 6Z...THEN
SLOWLY VEER TO THE SE/S AFT 12Z...THEN AFT 18Z TURN MORE W/NW AS
THE SFC LOW MOVES EAST OF THE AREA.
.WED NIGHT...IFR/MVFR CIGS.
.THU/FRI. MVFR CIGS/VSBYS IN -SN. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR BROWN-
CARVER-DAKOTA-GOODHUE-HENNEPIN-LE SUEUR-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-WASHINGTON-YELLOW
MEDICINE.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR ANOKA-BENTON-
CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MEEKER-MORRISON-
POPE-SHERBURNE-STEARNS-STEVENS-SWIFT-TODD-WRIGHT.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHISAGO-ISANTI-
KANABEC-MILLE LACS.
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR DUNN-EAU
CLAIRE-PEPIN-PIERCE-ST. CROIX.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHIPPEWA.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR BARRON-POLK-
RUSK.
&&
$$
CLF/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
552 AM CST MON FEB 27 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
THIS MORNING...AN UPPER LOW OVER THE UPPER GREAT LAKES WILL
CONTINUE TO MOVE EAST OVER THE NEW ENGLAND STATES BY MIDNIGHT
TONIGHT. A SFC HIGH PRESSURE RIDGE WILL ADVANCE OVER THE WESTERN
GREAT LAKES AND MIDWEST TODAY. SO A QUIET AND COOL DAY TODAY WITH
AFTERNOON HIGH TEMPERATURES IN THE 20S. THE LATEST WATER VAPOR
SATELLITE IMAGERY SHOWED A DEEPENING UPPER LOW OVER THE WEST COAST
WITH A STRONG UPPER LEVEL JET ROUNDING THE BASE OF THE UPPER LOW.
THIS LOW WILL CONTINUE TO STRENGTHEN OVER THE SOUTHERN ROCKIES
TODAY...BEFORE LIFTING INTO THE CENTRAL PLAINS ON TUESDAY.
TUESDAY AND WEDNESDAY TIMEFRAME...MODELS ARE IN GENERAL AGREEMENT
WITH THE POTENTIAL WINTER STORM. THE ONLY CHALLENGE IS DETERMINING
PRECIPITATION TYPES TUESDAY NIGHT. STILL BELIEVE THE BULK OF THE
PRECIPITATION WILL BE MAINLY SNOW FOR MUCH OF OUR AREA. THE LATEST
GEM-NHEM MODEL HAS THE SURFACE LOW OVER SOUTHEAST MN...LITTLE
FURTHER NORTH THAN THE NAM..GFS AND EC MODELS. THUS PREFERRED A
BLEND OF THE EC/GFS/NAM FOR POSITION AND TRACK OF THE SURFACE
LOW. THESE MODELS BRING THE SURFACE LOW ALONG THE IOWA/MINNESOTA
BORDER. THIS WILL PLACE MUCH OF OUR FORECAST IN BULLS-EYE OR CLOSE
IN RECEIVING 8+ INCHES OF SNOW...WITH PARTS OF WEST CENTRAL-
CENTRAL MN AND WESTERN WISCONSIN POSSIBLY OVER A FOOT. MODELS
CONTINUE TO SUPPORT LIQUID PRECIP TOTALS OF ONE TO TWO INCHES OVER
CENTRAL MN. WITH MIXING RATIOS IN THE 3-4 G/KG RANGE AND SNOW
ACCUMULATIONS VARYING 1.0-1.5 INCHES PER HOUR...SIX HOURLY
ACCUMULATION TOTALS COULD EASILY EXCEED OVER 10 INCHES. DUE TO
UNCERTAINTY ON THE TRACK AND PRECIPITATION TYPES DUE THE ENTIRE
EVENT...WILL HOLD OFF FROM UPGRADING THE BLIZZARD WATCH AND WINTER
STORM WATCH TO WARNINGS. DAY SHIFT SHOULD HAVE A FIRM GRASP ON THE
TRACK OF THE STORM.
THE SNOW WILL BEGIN TO DIMINISH OVER WESTERN MN DURING THE AFTERNOON
WEDNESDAY AS THE SURFACE LOW MOVES TOWARD THE LOWER GREAT
LAKES...WHILE MODERATE SNOW IS LIKELY TO CONTINUE OVER THE EASTERN
HALF OF THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL
PLAINS THURSDAY. ECMWF INTENSIFIES THIS LOW PRESSURE SYSTEM AS IT
LIFTS NORTHEAST OVER THE GREAT LAKES FRIDAY NIGHT. THIS SYSTEM
COULD BRING SOME MORE ACCUMULATING SNOWS TO THE EASTERN HALF OF
OUR FORECAST AREA FRIDAY AND FRIDAY NIGHT.
SUNDAY INTO MONDAY...LOOKS DRY AS AN UPPER RIDGE BUILDS OVER THE
NATIONS MIDSECTION.
&&
.AVIATION.../12Z TAF ISSUANCE/
SFC HIGH TO MOVE ACROSS THE TERMINALS...TODAY...RESULTING IN A
RELATIVELY CALM TAF PERIOD...BEFORE A SIGNIFICANT WINTER STORM
IMPACTS THE TERMINALS TUESDAY AFTERNOON INTO WEDNESDAY. BIGGEST
CHALLENGE THIS MORNING DEALS WITH TIMING BACK EDGE OF THE CLOUDS
THROUGH THE TERMINALS. LATEST 11-3.9 SAT IMAGERY SHOWS CLOUDS OVER
WRN MN...AND IN PARTICULAR AROUND RWF ALREADY BREAKING DOWN.
LEANED CLEARING IN TAFS MORE TOWARD THE RUC. LATE IN THE
TAF...WILL JUST SEE MID LEVEL CLOUDS INCREASE AS NEXT STORM SYSTEM
APPROACHES...THOUGH MOST OF THE PRECIP ASSOCIATED WITH IT LOOKS TO
HOLD OFF UNTIL AFTER 18Z TUE. WINDS WILL REMAIN GUSTY FOR THE FIRST
COUPLE HOURS IN THE EAST THIS MORNING...BUT SPEEDS WILL QUICKLY
COME DOWN UNDER 10 KTS AS THE SFC RIDGE MOVES IN. GIVEN THE SPEED
THE RIDGE MOVES THROUGH...WILL SEE WINDS QUICKLY BACK OVER TO THE
SE THIS AFTERNOON/EVENING.
KMSP...BASED ON SURROUNDING OBS...CIGS SHOULD REMAIN ABOVE 017
THIS MORNING...THOUGH A BRIEF PERIOD BELOW THIS LEVEL CAN NOT BE
RULED OUT THROUGH 15Z. BASED ON RUC TIMING...EXPECT CIGS TO CLEAR
BETWEEN 15Z AND 18Z. ARRIVAL OF NEXT SYSTEM CONTINUES TO SLOW IN
THE MODELS...AND SEEING ANY PRECIP EVEN IN THE 15-18Z PERIOD
TUESDAY MAY BE PUSHING IT...BULK OF THE PRECIP LOOKS TO ARRIVE
AFTER 21Z TUE.
//OUTLOOK...TUESDAY THROUGH FRIDAY...
.TUE-WED...CIGS/VSBY BECOMING LIFR. -SN DEV TUESDAY AFTERNOON...
LIKELY TRANSITIONS TO A MIX TUE NIGHT BEFORE GOING BACK TO SN WED
MORNING.
.WED NIGHT-THU...BECOMING VFR.
.FRI...IFR OR LOWER CIGS/VSBY POSSIBLE WITH CHANCE OF -SN.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHISAGO-
DAKOTA-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-
NICOLLET-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-
SIBLEY-STEARNS-STEELE-WASECA-WASHINGTON-WATONWAN-WRIGHT.
BLIZZARD WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-STEVENS-
SWIFT-TODD-YELLOW MEDICINE.
WI...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-
POLK-RUSK-ST. CROIX.
&&
$$
JVM/MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1143 PM CST SUN FEB 26 2012
.AVIATION.../06Z TAF ISSUANCE/
IFR/MVFR CONDITIONS WILL SLOWLY IMPROVE BY DAYBREAK AS THE SNOW
DIMINISHES FROM WEST TO EAST. INCLUDED TEMPO GROUPS AT DLH AND HYR
FOR IFR CEILINGS FROM 06Z TO 10Z. GUSTY NORTHWEST WINDS OVER BRD
WILL CONTINUE THROUGH 10Z. MAINLY MVFR CEILINGS FOR THE FIRST HALF
OF MONDAY BEFORE THE CLOUDS BREAK AND LIFT BY LATE MONDAY
AFTERNOON. WINDS WILL ALSO DECREASE THROUGHOUT THE DAY.
&&
.PREV DISCUSSION... /ISSUED 1033 PM CST SUN FEB 26 2012/
SHORT TERM...
RADAR AND OBSERVATIONS CONTINUE TO SHOW THE SNOW DECREASING IN
INTENSITY...WITH THE EXCEPTION OF OVER THE SOUTH SHORE OF LAKE
SUPERIOR...AND OVER PARTS OF THE ARROWHEAD. THE LOW WAS MOVING
TOWARD UPPER MICHIGAN/LAKE SUPERIOR THIS EVENING AND HAD
WEAKENED TO 1008MB. IF CURRENT TRENDS CONTINUE...WE WILL DROP THE
HEADLINES FOR CARLTON/SOUTHERN SAINT LOUIS AND PERHAPS THE REST OF
NORTHERN AND CENTRAL SAINT LOUIS COUNTIES AS WELL SHORTLY. WE WILL LEAVE
THE HEADLINES GOING FOR THE ARROWHEAD...AND SOUTH SHORE. WE`RE
STILL ON THE FENCE REGARDING PINE COUNTY. KDLH VELOCITY REVEALS
WINDS HAVE COME AROUND TO NORTH-NORTHWEST WITH SPEEDS AROUND 20 KT
IN THE LOWEST COUPLE THOUSAND FEET. NO CLEAR EVIDENCE YET IN RADAR
OF THE GRAVITY WAVE INDUCED AREA OF SNOWFALL...BUT RUC SUGGESTED
IT MAY TAKE A FEW MORE HOURS TO DEVELOP. WE ALSO MAY HAVE TO
INCREASE SNOW TOTALS A BIT ALONG THE SOUTH SHORE AS SPOTTERS HAVE
REPORTED HEAVIER SNOW THERE OVER THE PAST FEW HOURS...IRON BELT
HAD 2 INCHES IN A 3 HOUR PERIOD. NORTHERLY WINDS WITH DELTA-T`S
AROUND 13-15C AND THE LOW PRESSURE WILL CONTINUE TO PRODUCE
MODERATE SNOW SHOWERS ALONG PORTIONS OF THE SOUTH SHORE TONIGHT.
PREV DISCUSSION... /ISSUED 701 PM CST SUN FEB 26 2012/
SHORT TERM...
MODERATE TO HEAVY SNOW CONTINUED TO FALL OVER THE ARROWHEAD/IRON
RANGE...WITH LIGHTER SNOW OVER THE REST OF THE NORTHLAND. THE
SURFACE LOW IN NORTHWEST WISCONSIN WAS FILLING WITH NEAR 5 MB
PRESSURE RISES OVER THE EASTERN DAKOTAS AND 2 MB FALLS OVER THE UP
OF MICHIGAN. AREA RADARS AND OBSERVATIONS REVEAL SNOW INTENSITY
DIMINISHING OVER THE WESTERN CWA WHERE VSBYS HAVE CLIMBED TO 5SM
AT KPWC...3SM AT KXVG...8SM AT KGPZ AND 4SM AT KINL. WE WILL
WAIT A BIT LONGER...BUT WE SHOULD BE ABLE TO CANCEL SOME OF THE
HEADLINES IN THE WEST.
SPOTTERS IN PINE COUNTY REPORTED SOME MIXED SLEET/SNOW/FREEZING
DRIZZLE THIS EVENING. RUC13 SOUNDINGS REVEAL SEVERAL HOURS THIS
EVENING WHERE DRIER AIR WILL BE PRESENT ABOVE A MOIST LAYER THAT
REMAINS AT OR WARMER THAN -13C...SO A MIX WILL CONTINUE TO BE
POSSIBLE. SATELLITE IMAGERY ALSO SHOWS WARMER CLOUD TOPS PRESENT
OVER THAT AREA...INTO NORTHWEST WISCONSIN.
SNOW SHOULD GRADUALLY DIMINISH FROM WEST TO EAST
TONIGHT...REMAINING HEAVIEST IN THE ARROWHEAD. WE`LL ALSO HAVE TO
KEEP AN EYE ON THE SOUTH SHORE AS WINDS BACK AROUND TO THE NORTH
THEN NORTHWEST TONIGHT FOR SOME LAKE EFFECT SNOW SHOWERS. DELTA-T
VALUES ARE NOT ALL THAT HIGH...BUT THE COMBINATION OF LIFT FROM
THE SYSTEM AND THE LAKE WILL KEEP SNOW SHOWERS GOING LATER
TONIGHT. A GRAVITY WAVE INDUCED AREA OF ENHANCED SNOWFALL WILL
ALSO BE POSSIBLE SOUTH THROUGH PORTIONS OF DOUGLAS AND NORTHEAST
PINE COUNTIES LATE THIS EVENING AND OVERNIGHT AS WINDS BECOME
NORTHWEST. FLOW IS NOT ALL THAT STRONG...SO NOT SURE HOW STRONG
A WAVE WILL RESULT.
PREV DISCUSSION... /ISSUED 537 PM CST SUN FEB 26 2012/
AVIATION.../0Z TAF ISSUANCE/
CURRENT LIFR CONDITIONS OVER THE NORTHERN AERODROMES WILL SLIGHTLY
IMPROVE LATER THIS EVENING. SLIGHTLY BETTER CONDITIONS AT BRD AND
HYR WILL PREVAIL THROUGH THE EVENING. EXPECT THE LIGHT SNOW TO
SLOWLY DIMINISH OVERNIGHT WITH WINDS SHIFTING FROM THE NORTHWEST
LATER THIS EVENING. SNOW WILL END MONDAY MORNING WITH CEILINGS
IMPROVING TO LOW END VFR BY MONDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 347 PM CST SUN FEB 26 2012/
WINTER WEATHER ADVISORIES MAY BE CANCELLED EARLY OVER SWRN CWA
WINTER STORM WARNING MAY BE DOWNGRADED TO ADVISORY OVER SRN ST
LOUIS/CARLTON COUNTIES...
SHORT TERM...A GENERAL AREA OF 6 TO 10" HAS OCCURRED FROM NRN CASS
COUNTY ACROSS ITASCA COUNTY AND SCTRL ST LOUIS CO TO TWO HARBORS.
LESSER AMOUNTS ALONG BORDER IN NRN KOOCH CO AND NRN ST LOUIS
COUNTY. MSAS SHOWS MAIN SFC LOW NEAR KJMR TRACKING ENE TOWARDS
PRICE COUNTY AS OF MID AFTERNOON. MAIN FORCING HAS BEEN IN AREA OF
MESOSCALE LIFT ALONG NSHORE AND EXTENDING WEST UNDERNEATH A
DEFORMATION AXIS FROM THE IRON RANGE TO THE LEECH LAKE VICINITY.
85H LOW IS MOVING ACROSS BRD LAKES VICINITY TOWARDS DOUGLAS
COUNTY. 88D RETURNS INCREASING SIGNIFICANTLY IN THE PAST HR OVER
AITKIN COUNTY...AHEAD OF 85H LOW. PATCHY FREEZING DRIZZLE REPORTS
FROM NEAR BRUNO NORTH TO MOOSE LAKE AND INTO ADJACENT WISCONSIN AS
WARM ADVECTION LAYER HAS INCREASED ALOFT AHEAD OF MID LVL LOW. A
SECONDARY MID LVL SHORTWAVE TROF OVER CTRL NDAK HAS KEPT AN
EXTENSIVE AREA OF LIGHT SNOW WELL WEST OF REGION TODAY.
TONIGHT/TOMORROW...85H LOW WILL PASS ACROSS APOSTLE ISLANDS BY MIDNIGHT.
EXPECT BACKING OF BDRY LYR WIND TO AUGMENT SNOW ACROSS TWIN PORTS
AND INTO SOUTH SHORE THROUGH THE EVENING. SECONDARY SHORTWAVE TROF
WILL PASS ACROSS CWA LATE TONIGHT/EARLY TOMORROW. DEFORMATION AXIS
WILL PIVOT SOUTHEAST WITH SNOW DECREASING ACROSS WRN AND NWRN CWA.
SNOW SHOULD CONTINUE THROUGHOUT THE NIGHT OVER ERN HALF OF CWA.
HIGHEST ACCUMULATIONS WILL OCCUR ALONG NSHORE AND INLAND TO IRON
RANGE AND SHIFT MORE TOWARDS SOUTH SHORE BY EARLY MONDAY. PRECIP
SHOULD DIMINISH QUICKLY BY MID MORNING MOST AREAS AS UPPER TROF
MOVES EAST AND SUBSIDENT FLOW ALOFT DEVELOPS.
TOMORROW NIGHT...SFC HIGH WILL MOVE INTO REGION TEMPORARILY UNDER
BUILDING RIDGE ALOFT. MAY STILL HAVE SIGNIFICANT AMOUNT OF CLOUD
COVER ACROSS CWA AS MID/HIGH CLOUDS SNEAK INTO RIDGE ALOFT.
EXTENDED...TUESDAY THROUGH SUNDAY. THE MAJOR FOCUS FOR THE EXTENDED
TIME PERIOD IS THE MAJOR WINTER STORM SHAPING UP FOR TUESDAY THROUGH
WEDNESDAY NIGHT. THE MODELS ARE STARTING TO COME INTO BETTER
AGREEMENT CONCERNING A VERY HEAVY SNOWFALL EVENT. THERE IS SOME
DISAGREEMENT CONCERNING THE SPEED AT WHICH THE PRECIPITATION ARRIVES
ON TUESDAY. THE GFS...UKMET AND NAM QUICKLY BRING QPF ACROSS THE CWA
ON TUESDAY...WHILE THE ECMWF AND GEM ARE SLOWER IN BRINGING SNOW
BACK INTO THE AREA. WILL ISSUE A WINTER STORM WATCH FOR THE ENTIRE
SOUTHERN HALF OF THE CWA STARTING MIDDAY TUESDAY AND CONTINUING
THROUGH WEDNESDAY. THINK THE HEAVIEST SNOW WILL MOVE INTO THE REGION
TUESDAY NIGHT AND CONTINUE INTO WEDNESDAY. HAD A TOUGH TIME DECIDING
ON THE LOCATION OF THE WATCH. THE MODELS ARE IN A BIT BETTER
AGREEMENT CONCERNING HEAVY QPF VALUES IN THE SOUTHERN CWA...BUT THEY
HAVE ALL SHIFTED NORTHWARD OVER THE PAST FEW RUNS. THINK AT SOME
POINT WE MAY NEED TO EXTEND THE WATCH FURTHER NORTHWARD...AND INTO
THE NORTH SHORE AS WELL...BUT THIS SHOULD BE A GOOD START. ALSO
TRIED TO WATCH THE EXTENT OF THE DOUBLE HEADLINES IN THE AREA THAT
WAS SEEING VERY HEAVY SNOWFALL TODAY...FROM THE IRON RANGE INTO THE
ARROWHEAD/NORTH SHORE. THE STRENGTH OF THE SYSTEM...AND THE
AVAILABLE MOISTURE COULD LEAD TO IMPRESSIVE SNOWFALL RATES...VERY
STRONG WINDS AND A GREAT DEAL OF BLOWING AND DRIFTING SNOW. HAVE NOT
RULED OUT THE POSSIBILITY OF BLIZZARD CONDITIONS IN AREAS BORDERING
LAKE SUPERIOR...BUT WILL HOLD OFF FOR NOW ON ANY BLIZZARD WATCH. I
WOULD NOT BE SURPRISED TO SEE AMOUNTS WELL IN EXCESS OF ONE FOOT
SOMEWHERE IN THE NORTHLAND...BUT SPECIFIC AMOUNTS DEFINITELY TOO
TOUGH TO PINPOINT FOR ANY ONE LOCATION AT THIS POINT. THE STORM
SYSTEM MOVES OUT OF THE AREA WEDNESDAY NIGHT...AND SOME UNSETTLED
WEATHER MOVES IN LATER IN THE WEEK AND INTO THE WEEKEND. THE MODELS
ARE ALL OVER THE PLACE CONCERNING SPECIFIC PCPN CHANCES...BUT AT
THIS POINT IT LOOKS LIKE THERE COULD BE SOME MIXED PCPN.
&&
.POINT TEMPS/POPS...
DLH 27 15 23 12 / 100 100 10 10
INL 24 9 19 4 / 100 90 20 10
BRD 27 15 22 16 / 100 70 10 10
HYR 34 20 26 10 / 70 70 10 10
ASX 30 23 26 11 / 70 90 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ038.
WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR MNZ025-033>038.
WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ012-020-021.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ001>004.
WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR WIZ001>004-006>009.
&&
$$
SHORT TERM...MELDE
AVIATION...KK
AREA FORECAST DISCUSSION
NWS DULUTH MN
1033 PM CST SUN FEB 26 2012
.SHORT TERM...
RADAR AND OBSERVATIONS CONTINUE TO SHOW THE SNOW DECREASING IN
INTENSITY...WITH THE EXCEPTION OF OVER THE SOUTH SHORE OF LAKE
SUPERIOR...AND OVER PARTS OF THE ARROWHEAD. THE LOW WAS MOVING
TOWARD UPPER MICHIGAN/LAKE SUPERIOR THIS EVENING AND HAD
WEAKENED TO 1008MB. IF CURRENT TRENDS CONTINUE...WE WILL DROP THE
HEADLINES FOR CARLTON/SOUTHERN SAINT LOUIS AND PERHAPS THE REST OF
NORTHERN AND CENTRAL SAINT LOUIS COUNTIES AS WELL SHORTLY. WE WILL LEAVE
THE HEADLINES GOING FOR THE ARROWHEAD...AND SOUTH SHORE. WE`RE
STILL ON THE FENCE REGARDING PINE COUNTY. KDLH VELOCITY REVEALS
WINDS HAVE COME AROUND TO NORTH-NORTHWEST WITH SPEEDS AROUND 20 KT
IN THE LOWEST COUPLE THOUSAND FEET. NO CLEAR EVIDENCE YET IN RADAR
OF THE GRAVITY WAVE INDUCED AREA OF SNOWFALL...BUT RUC SUGGESTED
IT MAY TAKE A FEW MORE HOURS TO DEVELOP. WE ALSO MAY HAVE TO
INCREASE SNOW TOTALS A BIT ALONG THE SOUTH SHORE AS SPOTTERS HAVE
REPORTED HEAVIER SNOW THERE OVER THE PAST FEW HOURS...IRON BELT
HAD 2 INCHES IN A 3 HOUR PERIOD. NORTHERLY WINDS WITH DELTA-T`S
AROUND 13-15C AND THE LOW PRESSURE WILL CONTINUE TO PRODUCE
MODERATE SNOW SHOWERS ALONG PORTIONS OF THE SOUTH SHORE TONIGHT.
.PREV DISCUSSION... /ISSUED 701 PM CST SUN FEB 26 2012/
SHORT TERM...
MODERATE TO HEAVY SNOW CONTINUED TO FALL OVER THE ARROWHEAD/IRON
RANGE...WITH LIGHTER SNOW OVER THE REST OF THE NORTHLAND. THE
SURFACE LOW IN NORTHWEST WISCONSIN WAS FILLING WITH NEAR 5 MB
PRESSURE RISES OVER THE EASTERN DAKOTAS AND 2 MB FALLS OVER THE UP
OF MICHIGAN. AREA RADARS AND OBSERVATIONS REVEAL SNOW INTENSITY
DIMINISHING OVER THE WESTERN CWA WHERE VSBYS HAVE CLIMBED TO 5SM
AT KPWC...3SM AT KXVG...8SM AT KGPZ AND 4SM AT KINL. WE WILL
WAIT A BIT LONGER...BUT WE SHOULD BE ABLE TO CANCEL SOME OF THE
HEADLINES IN THE WEST.
SPOTTERS IN PINE COUNTY REPORTED SOME MIXED SLEET/SNOW/FREEZING
DRIZZLE THIS EVENING. RUC13 SOUNDINGS REVEAL SEVERAL HOURS THIS
EVENING WHERE DRIER AIR WILL BE PRESENT ABOVE A MOIST LAYER THAT
REMAINS AT OR WARMER THAN -13C...SO A MIX WILL CONTINUE TO BE
POSSIBLE. SATELLITE IMAGERY ALSO SHOWS WARMER CLOUD TOPS PRESENT
OVER THAT AREA...INTO NORTHWEST WISCONSIN.
SNOW SHOULD GRADUALLY DIMINISH FROM WEST TO EAST
TONIGHT...REMAINING HEAVIEST IN THE ARROWHEAD. WE`LL ALSO HAVE TO
KEEP AN EYE ON THE SOUTH SHORE AS WINDS BACK AROUND TO THE NORTH
THEN NORTHWEST TONIGHT FOR SOME LAKE EFFECT SNOW SHOWERS. DELTA-T
VALUES ARE NOT ALL THAT HIGH...BUT THE COMBINATION OF LIFT FROM
THE SYSTEM AND THE LAKE WILL KEEP SNOW SHOWERS GOING LATER
TONIGHT. A GRAVITY WAVE INDUCED AREA OF ENHANCED SNOWFALL WILL
ALSO BE POSSIBLE SOUTH THROUGH PORTIONS OF DOUGLAS AND NORTHEAST
PINE COUNTIES LATE THIS EVENING AND OVERNIGHT AS WINDS BECOME
NORTHWEST. FLOW IS NOT ALL THAT STRONG...SO NOT SURE HOW STRONG
A WAVE WILL RESULT.
PREV DISCUSSION... /ISSUED 537 PM CST SUN FEB 26 2012/
AVIATION.../0Z TAF ISSUANCE/
CURRENT LIFR CONDITIONS OVER THE NORTHERN AERODROMES WILL SLIGHTLY
IMPROVE LATER THIS EVENING. SLIGHTLY BETTER CONDITIONS AT BRD AND
HYR WILL PREVAIL THROUGH THE EVENING. EXPECT THE LIGHT SNOW TO
SLOWLY DIMINISH OVERNIGHT WITH WINDS SHIFTING FROM THE NORTHWEST
LATER THIS EVENING. SNOW WILL END MONDAY MORNING WITH CEILINGS
IMPROVING TO LOW END VFR BY MONDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 347 PM CST SUN FEB 26 2012/
WINTER WEATHER ADVISORIES MAY BE CANCELLED EARLY OVER SWRN CWA
.WINTER STORM WARNING MAY BE DOWNGRADED TO ADVISORY OVER SRN ST
LOUIS/CARLTON COUNTIES...
SHORT TERM...A GENERAL AREA OF 6 TO 10" HAS OCCURRED FROM NRN CASS
COUNTY ACROSS ITASCA COUNTY AND SCTRL ST LOUIS CO TO TWO HARBORS.
LESSER AMOUNTS ALONG BORDER IN NRN KOOCH CO AND NRN ST LOUIS
COUNTY. MSAS SHOWS MAIN SFC LOW NEAR KJMR TRACKING ENE TOWARDS
PRICE COUNTY AS OF MID AFTERNOON. MAIN FORCING HAS BEEN IN AREA OF
MESOSCALE LIFT ALONG NSHORE AND EXTENDING WEST UNDERNEATH A
DEFORMATION AXIS FROM THE IRON RANGE TO THE LEECH LAKE VICINITY.
85H LOW IS MOVING ACROSS BRD LAKES VICINITY TOWARDS DOUGLAS
COUNTY. 88D RETURNS INCREASING SIGNIFICANTLY IN THE PAST HR OVER
AITKIN COUNTY...AHEAD OF 85H LOW. PATCHY FREEZING DRIZZLE REPORTS
FROM NEAR BRUNO NORTH TO MOOSE LAKE AND INTO ADJACENT WISCONSIN AS
WARM ADVECTION LAYER HAS INCREASED ALOFT AHEAD OF MID LVL LOW. A
SECONDARY MID LVL SHORTWAVE TROF OVER CTRL NDAK HAS KEPT AN
EXTENSIVE AREA OF LIGHT SNOW WELL WEST OF REGION TODAY.
TONIGHT/TOMORROW...85H LOW WILL PASS ACROSS APOSTLE ISLANDS BY MIDNIGHT.
EXPECT BACKING OF BDRY LYR WIND TO AUGMENT SNOW ACROSS TWIN PORTS
AND INTO SOUTH SHORE THROUGH THE EVENING. SECONDARY SHORTWAVE TROF
WILL PASS ACROSS CWA LATE TONIGHT/EARLY TOMORROW. DEFORMATION AXIS
WILL PIVOT SOUTHEAST WITH SNOW DECREASING ACROSS WRN AND NWRN CWA.
SNOW SHOULD CONTINUE THROUGHOUT THE NIGHT OVER ERN HALF OF CWA.
HIGHEST ACCUMULATIONS WILL OCCUR ALONG NSHORE AND INLAND TO IRON
RANGE AND SHIFT MORE TOWARDS SOUTH SHORE BY EARLY MONDAY. PRECIP
SHOULD DIMINISH QUICKLY BY MID MORNING MOST AREAS AS UPPER TROF
MOVES EAST AND SUBSIDENT FLOW ALOFT DEVELOPS.
TOMORROW NIGHT...SFC HIGH WILL MOVE INTO REGION TEMPORARILY UNDER
BUILDING RIDGE ALOFT. MAY STILL HAVE SIGNIFICANT AMOUNT OF CLOUD
COVER ACROSS CWA AS MID/HIGH CLOUDS SNEAK INTO RIDGE ALOFT.
EXTENDED...TUESDAY THROUGH SUNDAY. THE MAJOR FOCUS FOR THE EXTENDED
TIME PERIOD IS THE MAJOR WINTER STORM SHAPING UP FOR TUESDAY THROUGH
WEDNESDAY NIGHT. THE MODELS ARE STARTING TO COME INTO BETTER
AGREEMENT CONCERNING A VERY HEAVY SNOWFALL EVENT. THERE IS SOME
DISAGREEMENT CONCERNING THE SPEED AT WHICH THE PRECIPITATION ARRIVES
ON TUESDAY. THE GFS...UKMET AND NAM QUICKLY BRING QPF ACROSS THE CWA
ON TUESDAY...WHILE THE ECMWF AND GEM ARE SLOWER IN BRINGING SNOW
BACK INTO THE AREA. WILL ISSUE A WINTER STORM WATCH FOR THE ENTIRE
SOUTHERN HALF OF THE CWA STARTING MIDDAY TUESDAY AND CONTINUING
THROUGH WEDNESDAY. THINK THE HEAVIEST SNOW WILL MOVE INTO THE REGION
TUESDAY NIGHT AND CONTINUE INTO WEDNESDAY. HAD A TOUGH TIME DECIDING
ON THE LOCATION OF THE WATCH. THE MODELS ARE IN A BIT BETTER
AGREEMENT CONCERNING HEAVY QPF VALUES IN THE SOUTHERN CWA...BUT THEY
HAVE ALL SHIFTED NORTHWARD OVER THE PAST FEW RUNS. THINK AT SOME
POINT WE MAY NEED TO EXTEND THE WATCH FURTHER NORTHWARD...AND INTO
THE NORTH SHORE AS WELL...BUT THIS SHOULD BE A GOOD START. ALSO
TRIED TO WATCH THE EXTENT OF THE DOUBLE HEADLINES IN THE AREA THAT
WAS SEEING VERY HEAVY SNOWFALL TODAY...FROM THE IRON RANGE INTO THE
ARROWHEAD/NORTH SHORE. THE STRENGTH OF THE SYSTEM...AND THE
AVAILABLE MOISTURE COULD LEAD TO IMPRESSIVE SNOWFALL RATES...VERY
STRONG WINDS AND A GREAT DEAL OF BLOWING AND DRIFTING SNOW. HAVE NOT
RULED OUT THE POSSIBILITY OF BLIZZARD CONDITIONS IN AREAS BORDERING
LAKE SUPERIOR...BUT WILL HOLD OFF FOR NOW ON ANY BLIZZARD WATCH. I
WOULD NOT BE SURPRISED TO SEE AMOUNTS WELL IN EXCESS OF ONE FOOT
SOMEWHERE IN THE NORTHLAND...BUT SPECIFIC AMOUNTS DEFINITELY TOO
TOUGH TO PINPOINT FOR ANY ONE LOCATION AT THIS POINT. THE STORM
SYSTEM MOVES OUT OF THE AREA WEDNESDAY NIGHT...AND SOME UNSETTLED
WEATHER MOVES IN LATER IN THE WEEK AND INTO THE WEEKEND. THE MODELS
ARE ALL OVER THE PLACE CONCERNING SPECIFIC PCPN CHANCES...BUT AT
THIS POINT IT LOOKS LIKE THERE COULD BE SOME MIXED PCPN.
AVIATION.../18Z TAF ISSUANCE/
A WINTER STORM WILL CONTINUE TO IMPACT THE NORTHLAND OVER MUCH OF
THE TAF PERIOD. AT THIS POINT...IT APPEARS THAT THE MOST DRAMATIC
VISIBILITY RESTRICTIONS WOULD BE ACROSS THE IRON RANGE AND THE
ARROWHEAD...WHERE A DEFORMATION AXIS WILL SET UP AND ROTATE
THROUGH THAT AREA. AREAS TO THE SOUTH AND FAR NORTH WILL SEE MORE
EPISODIC PERIODS OF HEAVIER SNOW. KHIB LOOKS TO SEE THE MOST
DRAMATIC VSBY RESTRICTIONS. OVERALL...FAIRLY WIDESPREAD MVFR TO
EVEN LIFR CONDITIONS CAN BE EXPECTED. CONDITIONS WILL IMPROVE
LATER TONIGHT AND ON MONDAY MORNING.
&&
.POINT TEMPS/POPS...
DLH 15 23 12 28 / 100 10 10 60
INL 9 19 4 28 / 90 20 10 10
BRD 15 22 16 30 / 70 10 10 70
HYR 18 26 10 32 / 70 10 10 60
ASX 21 26 11 31 / 90 30 10 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ038.
WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR MNZ025-033>038.
WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ011-012-
019>021-037.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ001>004.
WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR WIZ001>004-006>009.
&&
$$
SHORT TERM...MELDE
LONG TERM....DAP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1007 PM EST TUE FEB 28 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND NEW YORK STATE WILL
SLIDE TO THE EAST AS LOW PRESSURE OVER THE MIDWEST MOVES EASTWARD.
THERE WILL BE A MIX OF RAIN...SLEET AND SNOW ACROSS PARTS OF WESTERN
AND CENTRAL NEW YORK ON WEDNESDAY MORNING...THEN MAINLY RAIN AND
SNOW FOR THE AFTERNOON. RAIN WILL CHANGE BACK TO SNOW AND TAPER OFF
WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
THE OVERNIGHT PERIOD WILL BE CLOUDY AND MAINLY DRY. WHILE
COMPOSITE RADAR APPEARS FAIRLY OMINOUS...THE 00Z BUFFALO SOUNDING
SHOWS QUITE DRY AIR BELOW 700 MB. THUS THE MAJORITY OF THE
COMPOSITE RADAR IS ACTUALLY VIRGA. THIS SAID...REFLECTIVITY OF 25
DBZ OR SO SUGGESTS SOME FLURRIES ARE LIKELY REACHING THE GROUND
ACROSS CHAUTAUQUA COUNTY. THIS BAND OF MID-UPPER LEVEL WARM AIR
ADVECTION WILL CONTINUE TO LIFT OFF TO THE NORTH...PERHAPS
BRINGING A FLURRY TO BUFFALO AND FAR WESTERN NEW YORK.
HOWEVER...THIS SHOULD LIFT TO THE NORTH AROUND OR SHORTLY AFTER
MIDNIGHT...WHILE THE MAIN AREA OF PRECIPITATION SHOULD NOT ENTER
THE REGION UNTIL DAYBREAK. THE 18Z GFS/12Z RGEM/00Z HRRR ALL BRING
IN STEADY PRECIPITATION INTO FAR WESTERN PORTIONS OF NEW YORK JUST
SHY OF 12Z (700 AM). WITH CLOUDS IN PLACE ACROSS MOST OF THE
REGION... TEMPERATURES SHOULD DROP VERY LITTLE OVERNIGHT.
A WARM FRONT BETWEEN THE DEPARTING HIGH AND APPROACHING LOW WILL
BRING ABOUT A MIX OF WINTRY PRECIP TO PARTS OF WESTERN AND CENTRAL
NY. THIS WILL BRING A BAND OF WARM AIR ADVECTION IN THE LOWER TO
MID LEVELS...WHICH WILL LIFT FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION ON WEDNESDAY. THERE SHOULD BE A RATHER QUICK CHANGEOVER TO
RAIN IN FAR SOUTHERN SECTIONS...WHERE WINDS SHIFTING TO THE
SOUTHEAST WILL BRING IN WARM AIR ALOFT. FURTHER TO THE NORTH AND
EAST WILL BE FURTHER FROM THE SURFACE LOW AND CLOSER TO COLD HIGH
PRESSURE ANCHORED IN QUEBEC. THIS WILL ALLOW SNOW TO LAST
LONGER INTO WEDNESDAY...WITH LOCATIONS EAST OF LAKE ONTARIO LIKELY
TO STAY SNOW THROUGH SUNSET.
NO CHANGES TO HEADLINES WERE MADE FOR THE EVENING UPDATE. HAVE
SOME CONCERN THAT TEMPERATURES WEDNESDAY MORNING WILL BE SLOW TO
RISE...GIVEN THE INVERSION FORECAST TO DEVELOP BENEATH THE MODEST
SW FLOW ALOFT. THUS DID BUMP DOWN TEMPERATURES A FEW DEGREES ON
WEDNESDAY MORNING. ALSO NUDGED UP SNOW ACCUMULATIONS EAST OF
ROCHESTER. THE 18Z NAM CONTINUES TO BE COLDER THAN THE 18Z GFS AND
MOST OF THE 12Z MODELS...WITH THE SREF TENDING TO SUPPORT THE
WARMER MODEL CAMP AS WELL. A BLEND PROVIDES SIMILAR CHANGEOVER
TIMES TO GOING FORECAST...BUT PERHAPS A TAD MORE QPF BASED ON
LATEST CONSENSUS. EXPECT BETWEEN .25 AND .50 FROM THE BROAD BAND
OF WARM AIR ADVECTION. THIS SHOULD BRING LIGHT ACCUMULATIONS...GENERALLY
2 INCHES OR LESS...WEST OF ROCHESTER...WITH POTENTIAL FOR 2 TO 4
INCHES EAST OF ROCHESTER TO OSWEGO COUNTY THROUGH WEDNESDAY
EVENING.
THE GREATEST POTENTIAL FOR ANY ICE CONTINUES TO BE ACROSS THE
SOUTHERN TIER. WARM AIR ALOFT WILL CROSS QUITE EARLY WEDNESDAY
MORNING...HOWEVER BELOW FREEZING SURFACE TEMPERATURES WILL LIKELY
LINGER WELL INTO THE MORNING. WITH DEW POINTS IN THE UPPER TEENS
AND LOWER 20S...EXPECT SURFACE TEMPERATURES TO DROP EARLY
WEDNESDAY MORNING DUE TO EVAPORATIONAL COOLING. THE ADVISORY
APPEARS TO BE WELL PLACED FOR THIS...WITH A LIGHT GLAZE OF A TENTH
OF AN INCH OR SO OF ICE LIKELY IN THE ADVISORY AREA. IF SURFACE
TEMPERATURES DO LINGER BELOW FREEZING LONGER...IT IS POSSIBLE
ICING TO A QUARTER INCH COULD OCCUR.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A TOUGH FORECASTING SCENARIO FOR WEDNESDAY NIGHT WITH A FAIR AMOUNT
OF UNCERTAINTY ACROSS THE NORTH COUNTRY. THE EVENING STARTS WITH A
WARM FRONT DRAPED ACROSS WESTERN NEW YORK. TEMPERATURES ACROSS MUCH
OF THE FORECAST AREA WILL LIKELY BE ABOVE FREEZING WITH TEMPS
STAYING IN THE MID TO UPPER 30S AND THE ASSOCIATED ISENTROPIC UPLIFT
WILL BRING WIDESPREAD RAINFALL WITH AROUND A TENTH OF AN INCH OF QPF
INT HE WARM SECTOR AS THE PRECIP TAPERS OFF AND THE FOCUS SHIFTS TO
THE NORTH COUNTRY THROUGH THE EVENING HOURS. HEAVIER PRECIP WILL BE
POSSIBLE ACROSS THE NORTH COUNTRY ON THE NOSE OF THE LOW LEVEL JET.
THE BIG QUESTION HERE IS PRECIP TYPE...AS SURFACE TEMPS HERE WILL BE
HOVERING RIGHT AROUND FREEZING. THE NAM KEEPS TEMPERATURES ALOFT MOSTLY
BELOW FREEZING ACROSS THE NORTH COUNTRY FOR THE BULK OF THE
PERIOD...RESULTING IN PRECIP TYPE STAYING MOSTLY SNOW BEFORE
SWITCHING OVER TO RAIN WHEREAS THE GFS BRINGS A MUCH WARMER NOSE
OVER THE AREA SOONER IN THE EVENING...WHICH WOULD RESULT IN A MUCH
GREATER RISK OF FREEZING RAIN AND SLEET. HAVE TRIED TO SHOOT IN THE
MIDDLE FOR NOW WITH A LITTLE BIT OF EVERYTHING AND WILL HOLD OFF ON
AN ADVISORY GIVEN THE UNCERTAINTY REGARDING THE LOCATION/STRENGTH OF
THE WARM NOSE AND THE FACT THAT WE ARE TALKING ABOUT THE THIRD
PERIOD.
COLDER AIR ADVECTS ACROSS THE REGION THURSDAY AS A WEAK COLD FRONT
CROSSES WESTERN NEW YORK. AS THE ASSOCIATED UPPER LOW MOVES OVER THE
AREA...EXPECT RAIN SHOWERS...MIXING WITH SNOW OVER THE HIGHER
ELEVATIONS TO LINGER. TEMPERATURES WILL STAY RELATIVELY MILD WITH
HIGHS IN THE UPPER 30S TO AROUND 40 AS 850MB TEMPS ONLY DROP TO
AROUND -6C. POPS DROP OFF THURSDAY NIGHT AS RIDGING BUILDS OVERHEAD
AND LOWS DROP TO AROUND FREEZING.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE MAIN FOCUS FOR THIS PERIOD WILL BE A POTENTIALLY STRONG STORM
SYSTEM PROGGED TO IMPACT THE REGION THIS WEEKEND. MODEL AGREEMENT IS
FAIRLY DECENT ON THE TIMING OF THE CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS EARLY FRIDAY. THIS LOW MOVES UP INTO THE GREAT LAKES
FRIDAY NIGHT WHILE DEEPENING RAPIDLY COURTESY OF A STRONG UPPER
TROUGH IMMEDIATELY UPSTREAM AND A POWERFUL UPPER JET MOVING ACROSS
THE OHIO VALLEY INTO THE NORTHEASTERN U.S.. A VERY STRONG LOW LEVEL
JET WILL ADVECT AN EXTREMELY WARM AIRMASS INTO THE REGION AHEAD OF THE
APPROACHING LOW WITH 850MB TEMPS POTENTIALLY REACHING
+10C...YIELDING HIGHS THAT COULD EASILY REACH INTO THE 50S ON
FRIDAY. FOR FRIDAY NIGHT...INCREASING INSTABILITY AHEAD OF THE
APPROACHING FRONT GIVEN THE EXTREME WARM ADVECTION AND SHOWALTER
INDICES THAT DROP BELOW ZERO AND THE STRONG DYNAMICS ALOFT...HAVE
OPTED TO INCLUDE A MENTION OF THUNDERSTORMS. IN ADDITION...THE
POTENTIAL STRENGTH OF THE SOUTHERLY LOW LEVEL JET WILL CREATE THE
POTENTIAL FOR VERY STRONG WINDS ACROSS HIGH TERRAIN AND DOWNSLOPING
AREAS ALONG LAKE ERIE.
THE LOW PASSES TO OUR NORTHWEST INTO CENTRAL QUEBEC SATURDAY WHILE
SWEEPING A COLD FRONT ACROSS THE REGION. GIVEN THE VERY STRONG LOW
LEVEL JET AHEAD OF THE FRONT AND SUBSIDENCE BEHIND THE FRONT...SEE
THE POTENTIAL FOR ADVISORY TO LOW END WARNING LEVEL WINDS BEHIND THE
FRONT ON SATURDAY. AS ALWAYS THOUGH...IT IS BEST TO BE CAUTIOUS THIS
FAR OUT AS THERE ARE MANY MORE MODEL RUNS TO FINE TUNE THE DETAILS
OF THIS DEVELOPING STORM SYSTEM.
FOR SUNDAY AND MONDAY...THE LONGWAVE UPPER LEVEL TROUGH TRANSITS THE
REGION WITH COLD AIR SWEEPING ACROSS THE REGION USHERING IN A RETURN
TO WINTER. THE COLD ADVECTION WILL BRING A POTENTIAL FOR LAKES SNOWS
THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
EXPECT ONLY HIGH CLOUDS...WITH VFR CONDITIONS TO LAST THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE ON WEDNESDAY
MORNING. THIS WILL START AS SNOW OR MIXED
PRECIPITATION...EVENTUALLY TRENDING TO ALL RAIN. MIXED PRECIPITATION
AND SNOW WILL LAST LONGER TO THE NE...LASTING LONGER AT ART/ROC
THAN AT BUF/IAG/JHW. INCREASING MOISTURE WILL LIKELY LOWER ALL
SITES TO IFR OR LOWER AT TIMES WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT...MVFR IN RAIN...POSSIBLY SNOW NEAR ART.
THURSDAY...MVFR RAIN AND SNOW SHOWERS LIKELY.
FRIDAY...GENERALLY VFR.
SATURDAY...MVFR IN CHC OF SHOWERS.
SUNDAY...VFR/MVFR SCTD SNOW SHOWERS.
&&
.MARINE...
EASTERLY WINDS PICK UP ON THE LAKES LATER TONIGHT INTO WEDNESDAY
MORNING AS A WARM FRONT LIFTS NORTH ACROSS OHIO. WINDS AND WAVES
WILL INCREASE OVER WESTERN LAKE ONTARIO AND WILL WARRANT A SMALL
CRAFT ADVISORY FROM THE NIAGARA RIVER TO SODUS BAY. WINDS WILL VEER
TO THE SOUTH AND DIMINISH DURING THE AFTERNOON ON LAKE ERIE...WHILE
A MORE PERSISTENT EAST SOUTHEAST FLOW REMAINS IN PLACE ON LAKE
ONTARIO.
&&
.CLIMATE...
FEBRUARY 2012 HAS BEEN A PERSISTENTLY WARM MONTH...THOUGH NOT DAILY RECORD
WARMTH...THERE HAVE BEEN QUITE A NUMBER OF DAYS THIS MONTH THAT
HAVE REACHED OR EXCEEDED THE FREEZING MARK OF 32F. INCLUDING
TODAY`S MAXIMUM TEMPERATURE...BOTH BUFFALO AND ROCHESTER ARE
NEARING A RECORD NUMBER OF DAYS WITH 32F OR ABOVE MAXIMUM
TEMPERATURES THIS MONTH. WITH 2 DAYS REMAINING THIS FEBRUARY BOTH
CITIES MAY CLIMB HIGHER UP THE LIST. BELOW IS A LIST OF THE YEARS
WITH THE MOST AMOUNT OF FEBRUARY DAYS WITH FREEZING OR HIGHER
TEMPERATURES.
BUFFALO
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1998 25
2 2012 23
1884 23
4 1877 22
1890 22
AVG (1871-2012) 14.5
ROCHESTER
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1952 24
1998 24
3 2012 23
1931 23
1932 23
AVG (1871-2012) 15.0
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 5 AM TO NOON EST WEDNESDAY FOR
NYZ012>014-019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
LOZ042-043.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/WCH
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
933 PM EST TUE FEB 28 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS TONIGHT AND MOVE OFF
THE COAST ON WEDNESDAY. A COLD FRONT WILL MOVE INTO THE CAROLINAS
WEDNESDAY NIGHT AND MAY LINGER NEAR OR JUST SOUTH OF AREA BEFORE
MOVING BACK NORTH AS A WARM FRONT ON FRIDAY. ANOTHER STRONGER COLD
FRONT WILL BRING SHOWERS AND THUNDERSTORMS ON SATURDAY. COOLER AND
DRIER HIGH PRESSURE WILL BUILD INTO THE AREA SUNDAY INTO EARLY NEXT
WEEK BRINGING TEMPERATURES BACK TO SEASONABLE NORMS AFTER THE MID
WEEK WARMTH.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...SAT IMAGERY AND SFC OBS INDICATE MID LEVEL
CLOUD DECK CONTINUES JUST ON THE SW DOORSTEPS OF THE ILM CWA. MODEL
SOUNDINGS INDICATE PWS INCREASING FROM 1/2 INCH TO NEARLY 1 1/4
INCHES BY DAYBREAK WEDNESDAY. WHAT THIS SAYS IS THAT THE CLOUDS ON
THE WESTERN FRINGE OF THE ILM CWA WILL FINALLY BE ABLE TO MAKE SOME
FORWARD PROGRESS ACROSS THE ILM CWA. LATEST HRRR MODEL RUNS INDICATE
MUCH OF THE PCPN FALLING APART AS IT APPROACHES THE ILM CWA FROM THE
SW THRU W DURING THE OVERNIGHT. WILL THERE4 RUN WITH THE IDEA OF NO
POPS OVERNIGHT EVENTHOUGH THE PASSAGE OF A DYNAMIC-LESS WARM FRONTAL
BOUNDARY WILL BE ONGOING. WILL EXTRAPOLATE THE AMOUNT OF CLOUDINESS
TO CROSS THE FORECAST AREA FOR THE REMAINDER OF THE OVERNIGHT WITH
THE USE OF SAT IMAGERY TRENDS. PROGGED 8H TEMPS AND 1K-8H THICKNESS
INCREASE DRAMATICALLY BETWEEN 1 AM AND 7 AM WEDNESDAY. COULD BE
ONE OF THOSE NIGHTS WHERE THE LOWS ACTUALLY OCCUR THIS
EVENING...FOLLOWED BY TEMPS HOLDING STEADY OR SLOWLY INCREASING
DURING THE OVERNIGHT. COULD SEE ISOLATED -RA OR -SHRA AHEAD OF THE
WFP...OTHER THEN THAT...NO POPS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A PERIOD OF UNSETTLED WEATHER IS EXPECTED WED
INTO THU. A DEVELOPING WARM FRONT WILL MOVE ACROSS THE AREA WED
MORNING. A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA FROM THE
NW ON THU. AHEAD OF THE TROUGH...A DEEP SW TO WSW FLOW IS EXPECTED
TO DEVELOP. PRECIPITABLE WATER VALUES WILL INCREASE TO NEAR AN INCH
AND A HALF AS SW LOW LEVEL JET INCREASES TO 45 KT. TEMPS ON WED...
EVEN WITH CONSIDERABLE CLOUD COVER SHOULD FIND THEIR WAY INTO THE
70S AS H8 TEMPS CLIMB TO AROUND 13 DEG C. ALONG THE COAST...A
RESULTANT SEABREEZE WILL KEEP THE BEACHES COOLEST...UPPER 60S TO
LOWER 70S.
THE BEST SHORTWAVE ENERGY ASSOCIATED WITH THIS SYSTEM WILL TRAVEL TO
OUR DISTANT NORTH LATE WED NIGHT. HOWEVER...THERE SHOULD BE
SUFFICIENT LIFT IN THE WARM SECTOR...AHEAD OF THE TROUGH...TO BRING
A ROUND OF SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE A LIMITING
FACTOR AND MAINLY ELEVATED GIVEN THE BEST LIFT WILL ARRIVE DURING
THE LATE NIGHT AND EARLY MORNING HOURS. ALSO...A PRONOUNCED LOW
LEVEL INVERSION IS EXPECTED TO DEVELOP AROUND 1000 FT WHICH SHOULD
MAKE IT DIFFICULT FOR HIGHER WINDS ALOFT TO REACH THE SURFACE.
STILL...THE FORECAST AREA REMAINS IN A SLIGHT RISK FOR SEVERE
WEATHER LATE WED NIGHT INTO EARLY THU. STRONG STORMS ARE POSSIBLE
AND IT IS NOT IMPOSSIBLE FOR AN ISOLATED DAMAGING WIND GUST IN THE
STRONGEST STORMS.
TROUGH IS LIKELY TO GET HUNG UP JUST S OF THE FORECAST AREA AS IT
BECOMES PARALLEL TO THE FLOW. THIS WILL KEEP TEMPS WELL ABOVE NORMAL
THROUGH THE PERIOD WITH MORE 70S ON THU...AND AN 80 DEGREE READING
IS NOT OUT OF THE QUESTION AS DRIER AIR WORKS INTO THE AREA ALLOWING
FOR INCREASING SUNSHINE THROUGH THE AFTERNOON. A MORE WESTERLY
COMPONENT TO THE WIND DIRECTION WILL RESULT IN HIGHER TEMPS AT THE
BEACHES THU THAN ON WED. TEMPS BOTH NIGHTS WILL ALSO BE WELL ABOVE
NORMAL WITH WED NIGHT NOT GETTING BELOW THE UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...FOCUS FOR THE EXTENDED REMAINS ON THE FRONT
MOVING ACROSS THE SOUTHEAST SATURDAY THEN A COLDER AIRMASS AND
MINIMUM TEMPERATURES TUESDAY MORNING. HAVE INCREMENTALLY INCREASED
POPS FOR SATURDAY WITH CONFIDENCE A LITTLE HIGHER. STILL LOOKS LIKE
A SLOW TRUDGE ACROSS THE AREA AND WE HAVE POPS FOR SATURDAY AM
THROUGH SUNDAY AM.
BRIEF MID LEVEL TROUGHING MOVES ACROSS QUICKLY SUNDAY THROUGH
TUESDAY WITH A SECONDARY EMBEDDED SHORTWAVE LATE MONDAY INTO EARLY
TUESDAY. THIS FROM THE HPC FAVORED ECMWF. THE LATEST GFS HAS THIS
FEATURE EARLIER. IMPORTANT IMPACT ON LOWER TEMPERATURES TUESDAY
MORNING AS THE BOUNDARY LAYER SHOULD REMAIN WELL MIXED PREVENTING
RADIATIONAL CONDITIONS. ECMWF IS ALSO MORE AGGRESSIVE WITH THE QPF
AND WE MAY HAVE A FEW SPRINKLES/VIRGA TO CONTEND WITH.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...EXPECT VFR THROUGH THE VALID PERIOD...WITH CONDITIONS
POSSIBLY DETERIORATING TO MVFR/IFR DUE TO FOG DEVELOPMENT AND
ADDITIONAL LOW CIGS AFTER MIDNIGHT THROUGH LATE MORNING ON
WEDNESDAY. CURRENT OBS DEPICT AN AREA OF MID TO HIGH LEVEL CLOUDS
SLOWLY INFILTRATING INTO THE SOUTHERN MOST TIP OF OUR AREA IN SC.
ANTICIPATE THESE CLOUDS TO CONTINUE THEIR MIGRATION INTO THE AREA
OVERNIGHT. WITH THE VARYING NATURE OF OPACITY WITH THESE
CLOUDS...THE CONFIDENCE OF TIMING AND OCCURRENCE OF FOG ATTM IS
MODERATE. GENERALLY EAST WINDS OVERNIGHT WILL BE LIGHT. AFTER
DAYBREAK...LOW STRATOCUMULUS CLOUDS WILL LINGER BEFORE CIGS IMPROVE
TO VFR AGAIN BY LATE AFTERNOON...THOUGH EXPECT CLOUD COVER TO BE
BKN/OVC. CANNOT RULE OUT -DZ...HOWEVER HAVE NOT INTRODUCED INTO
CURRENT FORECAST GIVEN LOW CONFIDENCE. WINDS WILL GRADUALLY BECOME
SOUTHERLY...WITH GUSTS NEAR 20 KTS IN THE LATER AFTERNOON AND
SUBSIDING INTO THE EVENING HOURS.
EXTENDED OUTLOOK... A CHANCE FOR PRECIP WEDNESDAY NIGHT INTO
THURSDAY MORNING WITH A COLD FRONT. BECOMING VFR THURSDAY. CHANCE OF
RAIN CONTINUES FOR FRIDAY AND SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...EXPECT NE-E WINDS THIS EVENING...AHEAD
OF THE WARM FRONT. WINDS WILL VEER TO THE SE THEN S AFTER THE
WFP...WITH IT EXITING NORTH OF THE LOCAL WATERS BY DAYBREAK
WEDNESDAY. WIND SPEEDS WILL RANGE BETWEEN 10 TO 15 KT...THEN
INCREASE TO AROUND 15 KT AFTER THE WFP DURING THE LATE PRE-DAWN HRS
OF WEDNESDAY. SEAS WILL HOLD IN THE 2 TO 4 FT RANGE AND BEGIN TO
BUILD DURING THE SHORT TERM.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...EASTERLY WINDS 10 KTS OR LESS WED MORNING
WILL VEER AROUND TO THE SOUTH AND INCREASE THROUGH WED AHEAD OF
APPROACHING TROUGH. SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY
LATE WED EVE INTO THE FIRST HALF OF THU. SW WINDS WILL INCREASE TO
20 TO 25 KTS WED NIGHT AHEAD OF COLD FRONT. THIS WILL BUILD SEAS
TO 6 TO 7 FT WITH SOME 8 FOOTERS OUT NEAR FRYING PAN SHOALS. WINDS
AND SEAS WILL DIMINISH ON THU AND THIS TREND WILL PERSIST THROUGH
THU NIGHT. WINDS ARE EXPECTED TO REMAIN FROM THE SW FOR MOST OF THE
PERIOD...PERHAPS BRIEFLY VEERING TO WSW LATE THU NIGHT.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...LIGHT FLOW INITIALLY WILL QUICKLY RAMP UP LATER
FRIDAY AND CONTINUE THROUGH SATURDAY AS A FRONT MOVES ACROSS THE
SOUTHEAST. EXPECT A SOUTHWESTERLY FLOW OF 20-25 KNOTS AND ALONG WITH
A SMALL CRAFT ADVISORY TO BEGIN EARLY SATURDAY. THE FRONT MOVES
ACROSS THE WATERS EARLY SUNDAY AND WITHOUT A STRONG SURGE OF COLD
AIR IN ITS WAKE...EXPECT A WESTERLY FLOW OF AROUND 15 KNOTS.
REGARDING SEAS...WILL SEE HIGHEST VALUES...WELL OVER SMALL CRAFT
CRITERIA LATE SATURDAY DIMINISHING WITH THE CHANGE IN FETCH SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
942 PM CST TUE FEB 28 2012
.DISCUSSION...
HEAVY SNOW BAND HAS ENTERED THE FAR SOUTHERN CWA DURING THE LAST
FEW HOURS...BUT HAS BEEN VERY SLOW TO DO DO. CUT BACK ON NORTHWARD
PROGRESSION OF HIGH POPS TO FIT RADAR AND OBS TRENDS. THE 00Z NAM
AND HRRR MODELS CONTINUE THE TREND OF TRACKING THE SYSTEM FURTHER
SOUTH...WITH GFK RIGHT ON THE EDGE OF THE SNOW BAND. RADAR SHOWS
THE BAND OVER THE FAR SOUTHERN COUNTIES IS FAIRLY NARROW...BUT
AFTER A BREAK THERE IS A FAIR AMOUNT OF PRECIP FURTHER SOUTH NEAR
SIOUX FALLS. EVEN WITH THE FURTHER SOUTH TRACK OF THE
SYSTEM...THE NAM HAS MID LEVEL FRONTOGENESIS BANDS CONTINUING TO
TRACK INTO THE CWA THROUGH TOMORROW. BACKED OFF ON QPF AND SNOW
AMOUNTS A BIT...BUT WILL CONTINUE TO KEEP THE WARNING GOING.
NORTHERN TIER OF THE WARNING COUNTIES WILL BE ON THE VERY
EDGE...BUT IT COULD BE ANOTHER SITUATION LIKE LAST YEAR WHERE
WARNING AMOUNT SNOWS FALL NEAR THOMPSON WHILE GFK GETS NOT MUCH AT
ALL. DID REMOVE THE NORTHERN TIER OF COUNTIES FROM THE
ADVISORY...AS AREAS NEAR THE INTERNATIONAL BORDER WILL SEE AN INCH
OR LESS.
&&
.AVIATION...
MVFR CEILINGS CONTINUE TO MOVE NORTH...ALTHOUGH NOT AS FAST AS
PREVIOUSLY THOUGHT. IFR AND LOWER CEILINGS AND VIS WILL BE
POSSIBLE LATER TONIGHT AS THE STORM SYSTEM CONTINUES TO MOVE
THROUGH THE AREA. SNOW STILL HAS YET TO MAKE IT TO KFAR BUT SOME
-SN WITH VIS DOWN TO 1-3SM WILL ARRIVE WITHIN THE NEXT HOUR. THINK
THAT KFAR WILL BE THE MOST LIKELY TO GO DOWN TO 1/2SM WITH
MODERATE TO HEAVY SNOW...BUT SITES FURTHER NORTH WILL BE A BIT
BETTER AS FAR AS VIS GOES. CONDITIONS SHOULD BEGIN TO IMPROVE TO
MVFR BY TOMORROW AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 245 PM CST TUE FEB 28 2012/
SHORT TERM...
THE MAIN CHALLENGE WILL BE IMPENDING MAJOR WINTER STORM TO IMPACT
THE REGION TONIGHT AND WEDNESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT OVERALL WITH THIS SYSTEM...AND THE 12Z RUNS HAVE
DECREASED SNOW AMOUNTS QUITE A BIT NORTH OF THE HIGHWAY 2
CORRIDOR...WITH NOT MUCH SNOW NEAR THE CANADIAN BORDER. WILL NOT
BE DEVIATING FROM CURRENT HEADLINES THOUGH WITH RECENT FLIP/FLOPS
IN THE NORTH WITH THIS VERY CHALLENGING SYSTEM. MUCH MORE
CONFIDENT OF HEAVY SNOW AMOUNTS IN THE SOUTHERN FORECAST AREA
THOUGH...WITH SOME QUESTIONS IN THE NORTH STILL.
FOR TONIGHT...THERE WILL BE A RAPID DEVELOPMENT OF HEAVY SNOW IN
THE SOUTHERN FORECAST AREA AROUND OR SHORTLY AFTER 00Z. THERE WILL
BE A WARM LAYER SO SOME FREEZING RAIN IS POSSIBLE IN THE FAR SOUTH
THROUGH 09Z...AND WILL MENTION. EASTERLY WINDS WILL INCREASE AND
GUST UP TO 30 MPH...WHEN COMBINED WITH THE HEAVY SNOW...NEAR ZERO
VSBYS EXPECTED IN OPEN COUNTRY ALONG AND SOUTH OF THE INTERSTATE
94 CORRIDOR. THE SNOW WILL BE FAIRLY HEAVY IN NATURE GIVEN THE
WARM ATMOSPHERE AND HIGH PWATS OVER 0.60 INCHES...SO NOT SURE JUST
HOW GOOD THE SNOW WILL BLOW...BUT THERE WILL STILL BE PLENTY OF
BLOWING AND DRIFTING FOR SURE. WE WILL NEED TO MONITOR FOR
POTENTIAL BLIZZARD UPGRADES IN THE SOUTH IF WINDS INCREASE SOME...
BUT GIVEN WARMER AIR IN THE SOUTH AND MORE OF AN EASTERLY COMPONENT...
FEEL CONFIDENT WITH CURRENT HEADLINES AT THIS POINT AND WILL LEAVE AS
IS.
ON WED...THE LOW WILL SHEAR TO THE EAST AND CONDITIONS WILL
CONTINUE TO IMPROVE. NOT SURE JUST HOW FAR NORTH THE ACCUMULATING
SNOW BAND WILL MAKE IT. THE NORTHERN EXTENT WILL BE AFFECTED BY
THE 850MB WINDS AND MOISTURE TRANSPORT...WITH MODELS SHOWING MORE
OF A CUT OFF OF SNOW TO THE NORTH AND NOT MUCH OF ANY
ACCUMULATION NEAR THE CANADIAN BORDER. THERE SHOULD BE A
DEFORMATION SNOW BAND AND WINDS SHIFTING TO THE NORTH WED
MORNING...SO CONSIDERABLE BLOWING AND DRIFTING SNOW SHOULD PERSIST
THROUGH AT LEAST 18Z IN THE VALLEY. TOTAL SNOW ACCUMULATIONS WILL
VARY GREATLY WITH THE SOUTHERN VALLEY GETTING A FOOT OR
MORE...WITH INTERNATIONAL BORDER AREAS PERHAPS NOT GETTING MUCH AT
ALL. THE BIG QUESTION WILL BE WHERE THE DIVIDING LINE FROM
SIGNIFICANT ACCUMULATIONS TO NOT MUCH ACCUMULATIONS WILL BE...AND
THIS MAY BE WITHIN 30 MILES EITHER SIDE OF THE HIGHWAY 2
CORRIDOR.
FOR THU/FRI...THERE WILL BE ANOTHER SHORTWAVE AND CONTINUED
CHANCES FOR
LONG TERM (FRI NIGHT-TUE)...
REGION LOOKS TO STAY IN NORTHWEST FLOW ALOFT THROUGH THE EARLY PART
OF THE LONG TERM PERIOD AND MODELS ARE PRETTY CONSISTENT WITH THAT.
COULD BE SOME MINOR DISTURBANCES THAT DRIFT DOWN THRU THE FA THAT
COULD BRING SOME LIGHT SNOW CHANCES FRI NIGHT THRU SAT NIGHT. THIS
WOULD NOT BE ANYTHING SIGNIFICANT BUT RATHER JUST THE LIGHT SNOW OR
FLURRY VARIETY. TEMPS LOOK TO REMAIN PRETTY CLOSE TO NORMAL FOR
EARLY MARCH. START TO SEE MORE DIFFERENCES BETWEEN THE MODELS BY
LATER IN THE LONG TERM PERIOD. 12Z OPERATIONAL RUNS BY 00Z TUE
EITHER SHOW A RIDGE OR A TROUGH. ECMWF SHOWS A MUCH SLOWER TROUGH
WHILE THE GFS IS MUCH QUICKER. THEREFORE TEMPS ARE ALL OVER THE
PLACE TOO WITH THE GFS BECOMING COLDER FASTER AND THE ECMWF STAYING
WARM. WILL STAY WITH THE WARMER ROUTE TODAY AND SEE WHAT THE MODELS
BRING WITH FURTHER RUNS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR NDZ024-026>030-
038-039-049-052-053.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR NDZ014>016-
054.
MN...WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR MNZ001>003-
013>017-022>024-027>032-040.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR MNZ007>009.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
332 PM EST MON FEB 27 2012
.SYNOPSIS...
HIGH PRESSURE TO THE WEST WILL QUICKLY BUILD EAST OVER THE AREA
TONIGHT. THE HIGH WILL MOVE TO THE EAST COAST BY LATE TUESDAY.
ANOTHER STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL
GREAT LAKES WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
BIG ISSUE IN THE SHORT TERM WILL BE THE WINDS THIS EVENING IN
RESPONSE TO A RATHER TIGHT GRADIENT BETWEEN LOW PRESSURE OVER THE
NORTHERN GREAT LAKES AND STRONG HIGH PRESSURE OVER THE PLAINS
QUICKLY BUILDING TOWARD THE AREA. HAVE EXPANDED THE WIND ADVISORY
ACROSS EASTERN COUNTIES WITH EXCEPTION FOR THE FAR SOUTH THROUGH
THIS EVENING. HRRR MODEL RUNS HAVE BEEN HANDLING THE WINDS RATHER
WELL THIS AFTERNOON...AND THEY HAVE ADVISORY WIND GUSTS PUSHING
THROUGH NORTHEAST OHIO COUNTIES OVER THE NEXT SEVERAL HOURS. WINDS
SHOULD DIMINISH QUICKLY FROM WEST TO EAST ESPECIALLY AFTER SUNSET
TONIGHT. AFTER MIDNIGHT EXPECTING WINDS TO BE DOWN BELOW 10 MPH.
ASIDE FROM THAT A DRY AND MOSTLY CLEAR NIGHT EXPECTED WITH TEMPS
DROPPING BACK TO THE LOWER TO MID 20S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE OVER THE AREA TUESDAY MORNING...THEN MOVING TO THE
EAST WILL ALLOW FOR A QUIET AND DRY WEATHER DAY WITH SEASONABLE
TEMPERATURES. LATEST MODELS SEEM TO BE DELAYING THE ONSET OF THE
PRECIP ACROSS THE AREA TUESDAY NIGHT. WHILE CLOUDS ARE EXPECTED TO
OVERSPREAD THE REGION EARLY ON...THINKING PERHAPS NOT TOWARD 06Z
ACROSS THE SOUTHWEST AREAS AND NOT UNTIL CLOSE TO 12Z WED FOR
PRECIP ACROSS NW PA. DO BRING UP POPS QUICKLY ACROSS THE AREA
THOUGH AFTER 06Z. STILL SOME QUESTION AS TO PRECIP TYPE AT THE
ONSET ESPECIALLY FROM CLE-CAK NORTHEAST. ACROSS OH THINKING THAT
THERE MAY BE A RAIN/SNOW MIX WITH BEST CONFIDENCE OF ALL SNOW AT
THE ONSET FOR FAR NE OH AND NW PA. MODELS SHOWING LOWER LEVELS
WARMING UP ENOUGH BY 12Z WED THOUGH THAT MANY LOCATIONS WILL
SWITCH OVER TO RAIN.
MODELS LEANING TOWARD A MORE NORTHERN TRACK OF THE LOW CENTER
ALLOWING MUCH OF THE AREA TO GET WARM ON WED. LEFT THE HIGH POPS
AND MENTION OF THUNDER IN THE MORNING...BUT THEN CONCERNED ABOUT
DRY SLOT MOVING ESPECIALLY INTO WESTERN AREAS FOR THE AFTERNOON SO
REDUCED POPS AND CLOUDS A BIT ACROSS THE WEST. TEMPS WILL ALSO BE
TRICKIEST DURING WED SO FOR NOW USED A BLEND OF MAV AND MET
NUMBERS. CONCERNED MOST ABOUT NORTHERN AREAS WHICH MAY GET WARMER
THAN FORECAST. ALSO CONCERNED ABOUT WIND POTENTIAL ON WED
ESPECIALLY ACROSS THE WEST WHERE BETTER MIXING IS POSSIBLE.
LOW PRESSURE NORTH OF THE AREA WEDNESDAY NIGHT AND THROUGH MUCH OF
THURSDAY WILL ALLOW FOR SOME RAIN/SNOW SHOWERS MAINLY ACROSS THE
NORTH WEDNESDAY NIGHT...THEN CONTINUED CHANCES FOR SHOWERS ACROSS
NE OH AND NW PA THROUGH MUCH OF THURSDAY. HIGH PRESSURE RIDGING IN
WILL DRY OUT THE AREA THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
SOUTHERLY WINDS WILL BE ON THE INCREASE ON FRIDAY AS LOW PRESSURE
MOVES FROM THE CENTRAL PLAINS TO THE CENTRAL GREAT LAKES BY FRIDAY
EVENING. THIS WILL PROVIDE WARM CONDITIONS FOR THE REGION WITH HIGHS
INTO THE 50S FOR MOST LOCATIONS. RAIN CHANCES WILL BE ON THE
INCREASE FRIDAY EVENING INTO THE OVERNIGHT. SOME RAIN MAY LINGER
INTO SATURDAY MORNING. COOLER AIR WILL SPILL ACROSS THE LAKE
SATURDAY NIGHT INTO EARLY SUNDAY AND COULD BE JUST COLD ENOUGH TO
PROVIDE A FEW SNOW SHOWERS OFF OF LAKE ERIE. ANOTHER FAST MOVING
STORM SYSTEM MAY AFFECT THE REGION SUNDAY NIGHT AND MAY ENHANCE ANY
SNOW SHOWERS THAT ARE IN THE AREA.
SLIGHTLY COOLER ON SATURDAY WITH HIGHS BACK INTO THE 40S. EVEN
COOLER BY SUNDAY INTO MONDAY WITH HIGHS AT MOST LOCATIONS WITHIN A
COUPLE DEGREES OF 40.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
GUSTY WINDS WILL CONTINUE TO MOVE ACROSS NORTHERN OHIO THROUGH THE
AFTERNOON. EASTERN AREAS WILL SEE THESE STRONGER WINDS ARRIVE AS
THE MIDDLE LEVEL CLOUD COVER GIVES WAY TO CLEAR SKIES. IT APPEARS
AT THIS TIME THAT WESTERLY WINDS WILL GUST IN THE 25 TO NEAR 40
KNOT RANGE. THE STRONGEST GUSTS WILL GENERALLY BE NEAR AND NORTH OF
A LINE FROM FINDLAY TO ERIE.
THE WINDS WILL DECREASE SHORTLY AFTER SUNSET WITH VFR CONDITIONS
ANTICIPATED THROUGH THE NIGHT. WE WILL HAVE TO MONITOR NE OH INTO
NW PA FOR SOME LOWER LEVEL VFR CEILINGS FOR A BRIEF PERIOD AFTER
MIDNIGHT. OTHERWISE EXPECT TO SEE SOME MIDDLE AND HIGH LEVEL CLOUD
COVER RETURN FROM WEST TO EAST TUESDAY MORNING INTO THE EARLY
AFTERNOON.
OUTLOOK...PERIODS OF NON-VFR WILL RETURN TUESDAY NIGHT AND
CONTINUE AT TIMES THROUGH THURSDAY. NON-VFR MAY RETURN BY FRIDAY
NIGHT INTO SATURDAY.
&&
.MARINE...
A COLD FRONT MOVING ACROSS LAKE ERIE THIS AFTERNOON IS RESPONSIBLE
FOR STRONG WESTERLY WINDS OF 20 TO 30 KNOTS. WINDS ARE APPROACHING
GALE FORCE ON THE EAST END OF THE LAKE BUT SHOULD REMAIN JUST BELOW
GIVEN THAT THE COLD ADVECTION BEHIND THE FRONT IS NOT THAT STRONG.
SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL NEARSHORE WATERS AND
WILL COME TO AN END FROM WEST TO EAST OVERNIGHT AS HIGH PRESSURE
BUILDS OVERHEAD AND WINDS/WAVES QUICKLY DECREASE.
EASTERLY WINDS WILL INCREASE ON TUESDAY NIGHT AHEAD OF THE NEXT LOW
PRESSURE SYSTEM TRACKING OUT OF THE PLAINS. WE WILL HAVE TO MONITOR
THE EXACT TRACK AND STRENGTH OF THE SURFACE LOW FROM WEDNESDAY INTO
THURSDAY TO DETERMINE MOST LIKELY WINDOW OF SMALL CRAFT ADVISORY
CONDITIONS. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED ON THE EAST
END OF THE LAKE FOR THURSDAY BUT MAY NEED TO BE EXPANDED TO THE
WEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR OHZ012>014-
021>023-031>033-089.
WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR OHZ003-006>011-
017>020-027>030.
PA...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR PAZ001>003.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LEZ144>149.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LEZ142-
143.
&&
$$
SYNOPSIS...ABE
NEAR TERM...ABE
SHORT TERM...ABE
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...KEC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
644 PM CST TUE FEB 28 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY INDICATES LOW
PRESSURE EMERGING FROM THE ROCKIES INTO WESTERN KANSAS THIS AFTERNOON...WITH
ITS ASSOCIATED WARM FRONT LIFTING NORTH ALONG THE KS/NE BORDER AND
ACROSS MISSOURI. CONVECTION HAS DEVELOPED ALREADY AHEAD OF THE LOW
JUST AHEAD OF A POTENT DRY SLOT PUNCHING INTO NEBRASKA. CLOSER TO
HOME...LEADING EDGE OF RETURN MOISTURE IS NOW PUSHING INTO SOUTHERN
WISCONSIN A TAD AHEAD OF SCHEDULE...AS EVIDENT BY A BAND OF RAIN AND
SNOW. EARLIER MODERATE SNOW OVER N-C WISCONSIN IS HANGING ON ALONG
THE U.P. BORDER WHERE THEY RECEIVED 2-3 INCHES OF SNOW. BUT THE
MAIN PROBLEM FOR THIS FORECAST IS THE LOW OUT WEST AND HEAVY SNOW
POTENTIAL AS IT MOVES ACROSS THE REGION TONIGHT INTO WEDNESDAY.
TONIGHT...LOW PRESSURE OVER THE PLAINS WILL MOVE NORTHEAST AND
OCCLUDE AS IT MOVES INTO SOUTHWEST MINNESOTA BY 12Z WEDNESDAY.
AHEAD OF THE LOW...A 40-50KT LLJ WILL RAMP UP AND SHIFT INTO
NORTHERN ILLINOIS DURING THE OVERNIGHT HOURS. THIS LLJ WILL
TRANSPORT RICH GULF OF MEXICO MOISTURE NORTHEAST WITH PWATS OF
UPWARDS OF 0.75 INCHES REACHING INTO CENTRAL WISCONSIN. THIS IS
OVER 200 PCT OF NORMAL AND 2 STANDARD DEVIATIONS ABOVE NORMAL.
BEFORE THIS OCCURS THOUGH...LEADING EDGE OF THE RETURN MOISTURE ON
THE 285K SURFACE IS CREATING A BAND OF LIGHT RAIN AND SNOW WHICH
SHOULD APPROACH CENTRAL WISCONSIN LATE THIS AFTERNOON AND INTO THE
FOX VALLEY BY EARLY IN THE EVENING. WET BULB TEMPS HAVE BEEN RISING
THIS AFTERNOON...BUT FIGURING SNOW OVER CENTRAL WISCONSIN...AND
RAIN/SNOW MIX OVER EAST-CENTRAL WHERE ONSHORE FLOW WILL CONTINUE.
THE MAIN SURGE OF PRECIPITATION SHOULD NOT ARRIVE UNTIL LATE INTO
THE EVENING AND THE OVERNIGHT HOURS WHEN FORCING VIA LLJ AND
MID-LEVEL FGEN LIFTS INTO THE REGION. WITH MID-LEVEL LAPSE RATES OF
6.5-7 C/KM AND NEGATIVE EPV ABOVE THE FGEN LAYER...CONVECTION IS
DEFINITELY POSSIBLE WITH THE PRECIPITATION OVERNIGHT...AND UPSTREAM
OBS BEAR THIS OUT AS WELL. THERMAL PROFILES VARY WIDELY BETWEEN THE
WARMER GFS AND THE COLDER ECMWF/NAM. ALTHOUGH THERE IS PLENTY OF
WARM AIR TO OUR SOUTH...THE WARM LAYER IS MARGINALLY HIGH AT AROUND
800MB WHICH LEAVES THE POTENTIAL FOR CONVECTION TO WIPE OUT THAT
WARM NOSE...THEREBY KEEPING THE PROFILE NEAR OR JUST BELOW FREEZING
OVER CENTRAL AND EAST-CENTRAL WISCONSIN. AS A RESULT...HAVE BOOSTED
SNOW AMOUNTS OVER CENTRAL WISCONSIN AND THE NORTHERN FOX VALLEY. AM
MOST CONFIDENT OF RAIN/SLEET MIXING IN OVER KEWAUNEE AND MANITOWOC
COUNTIES THANKS TO THE LAKE INFLUENCE. SE WINDS WILL ALSO RAMP UP
OVERNIGHT WHICH COULD CREATE NEAR WHITE OUT VSBYS AT TIMES WITHIN
THE HEAVY SNOW. WILL UPGRADE DOOR COUNTY TO WARNING CRITERIA...AS
THEY DO SURPRISINGLY WELL IN CASES LIKE THIS...WHERE COLDER AIR AT
925MB WILL HANG ON THE LONGEST. OTHERWISE...CURRENT HEADLINES LOOK
GOOD FOR WARNING/ADVISORY CONFIGURATION. THE NEXT SHIFT WILL HAVE
TO MONITOR FOR UPGRADES FOR THE NEXT ROW OF COUNTIES SOUTH OF THE
WARNING IF CONVECTION DOES COOL THE COLUMN ENOUGH FOR A MOSTLY SNOW
PTYPE.
WEDNESDAY...OCCLUDED LOW PRESSURE WILL SLOW AND MOVE FROM SW
MINNESOTA TO WESTERN WISCONSIN OVER THE COURSE OF THE DAY. LOW
LEVEL WARM AIR WILL CONTINUE TO WRAP AROUND THE LOW INTO EASTERN
WISCONSIN DURING THE MORNING...WHILE THE DRY SLOW MOVES IN ALOFT.
MODERATE TO HEAVY SNOW WILL BE WIDESPREAD NORTH AND WEST OF THE DRY
SLOT OVER NORTHERN AND NORTHWEST WISCONSIN FOR MUCH OF THE MORNING.
BUT FARTHER SOUTH...THE DRY SLOT WILL MAKE IT DIFFICULT FOR ICE
CRYSTALS TO GET INTRODUCED INTO THE CLOUD...SO HAVE ADDED THE CHANCE
OF FREEZING DRIZZLE OVER CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
RAIN OR DRIZZLE SHOULD BE MIXING WITH SNOW BY THE TIME OF THE
MORNING COMMUTE OVER THE FOX VALLEY AND LAKESHORE WHICH LOOKS TO BE
A SLOPPY MESS. SHOULD ALSO SEE A PERIOD OF OF JUST RAIN/DRIZZLE AS
WELL...MID-MORNING THROUGH MID-AFTERNOON BEFORE COLDER AIR SURGES
EAST AS IT WRAPS AROUND THE LOW. WITH ALL THIS IN MIND...TOTAL
SNOWFALL ACCUMULATION THROUGH 00Z THU LOOKS LIKE 10-15 INCHES OVER
N-C WISCONSIN...6-10 NORTH OF A MARSHFIELD TO STURGEON BAY
LINE...AND 3-7 INCHES FOR CENTRAL WISCONSIN AND MUCH OF THE FOX
VALLEY. DID END HEADLINES EARLY FOR THE FOX VALLEY AND
LAKESHORE...AS SNOW CHANGING TO RAIN SHOULD CAUSE CONDITIONS TO
RAPIDLY IMPROVE BY 18Z WED.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
PERIOD TO SEE SHIFT FROM OUR SPLIT FLOW PATTERN TO A MORE
CONSOLIDATED FLOW WITH TROF SHIFTING EAST THROUGH THE LAKES REGION
THIS WEEKEND. TEMPS FOR SAT AND SUN EXPECTED TO BE AOB NORMS. RIDGE
TO FOLLOW FOR MUCH OF THE WORK WEEK FOR A DRY AND MILD PERIOD.
WED NIGHT TO THU...STORM TO BE EXITING THE AREA WITH SNOW ENDING
WEST TO EAST. LEFT OUT OF GRIDS AT THIS TIME...THOUGH MODEL
SOUNDINGS INDICATE SOME FREEZING DRIZZLE POSSIBLE OVER THE EAST
BEHIND SYSTEM. WEAK HIGH PRESSURE MOVES THROUGH DURING DAY
THU...SMALL CHANCE OF LAKE EFFECT FAR NW VILAS IN THE MORNING
THOUGH SUPPORT FOR THAT WEAKENS BY AFTERNOON.
THU NIGHT TO FRIDAY...MODELS STILL HAVING DIFFICULTY THIS
PERIOD...THOUGH STARTING TO GEL A BIT. TROF OF LOW
PRESSURE/DEVELOPING COLD FRONT MOVES EAST INTO STATE LATE THU
NIGHT. SIG WAA AHEAD OF SYSTEM AND SOME FGEN SAYS KEEP SMALL
POPS...MAINLY NORTH...UPPER SUPPORT WEAK THOUGH. ALL MODELS WANT TO
DEVELOP WAVE ON FRONT SOUTH OF STATE...BRING IT NE ALONG FRONT.
MOST TO OUR EAST...THOUGH GFS REMAINS CONSISTENT BRINGING LOW
THROUGH STATE. EITHER WAY KEPT CHANCE POPS HIGHEST EAST. SOME
CONCERN WITH PCPN TYPE...WILL GO FOR MIX EAST...THOUGH LATEST EC
BRINGING COLDER AIR FURTHER EAST.
WEEKEND...HINTS AT POSSIBLE CLIPPER SYSTEM SUN...AND POSSIBLE
LAKE EFFECT FAR NORTHWEST CWA WITH NORTHWEST FLOW.
&&
.AVIATION...CONDITIONS WILL FALL TO IFR FROM WEST TO EAST THIS
EVENING AS WINTER STORM APPROACHES FROM THE CENTRAL PLAINS. MOSTLY
SNOW EXPECTED OVERNIGHT NORTH OF A WAUSAU TO STURGEON BAY LINE
WITH A MIXTURE OF SNOW...SLEET AND FREEZING RAIN FURTHER SOUTH.
SNOW ILL CONTINUE WEDNESDAY NORTH OF RHINELANDER WITH SCATTERED
LIGHT RAIN OR DRIZZLE FURTHER SOUTH. CIGS MAY FALL TO NEAR
AIRFIELD MINIMUMS LATE TONIGHT AND WEDNESDAY.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ038>040-
048>050.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ035>037-
045.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ005-010-011-
018>020-030-031.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ012-013-021-
073-074.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS BOISE ID
908 PM MST TUE FEB 28 2012
.DISCUSSION...THE COLD FRONT ALONG THE OREGON COAST HAS BROUGHT
GUSTY PREFRONTAL SW WINDS TO SE OREGON /G25 MPH KREO/ AND BRIEFLY
VERY LIGHT SNOW /0.01 INCHES/ TO BURNS. THUNDERSTORMS OCCURRED
THIS AFTERNOON AND EVENING OFFSHORE /WA-OREGON/ AND OVER THE
COASTAL WATERS OFF BROOKINGS OREGON. LATEST RUC/NAM ARE SLOWER TO
BRING PRECIPITATION ACROSS OUR AREA WITH THE RUC HOLDING OFF TILL
9Z KBNO-KBKE-KMYL WWD. THE NAM DEVELOPS /OROGRAPHIC/ PCPN OVER
CENTRAL IDAHO BY 6Z WITH BUT THE MAIN QPF EVENT IS WITH AND BEHIND
THE FRONT IN THE NAM. THE NAM SEEMS TO BE THE WAY TO GO PER
OBS/TRENDS. THIS IS NOT THE FIRST TIME COASTAL CONVECTION AND
A LOWER/SLOWER INLAND QPF HAVE SEEMED TO GO TOGETHER. DO LIKE THE
IDEA OF OROGRAPHIC FORCING FOLLOWED BY A ROUND OF HEAVIER
PRECIPITATION WITH AND BEHIND THE FRONT ACROSS BURNS/BAKER
10-12Z...BOISE AROUND 14Z...TWF 17-19Z. GUSTY SE TO S WINDS WILL
SHIFT TO WEST WITH THE FRONT WITH BRIEF GUSTS TO 45 MPH. AS THE
UPPER TROUGH CROSSES THE AREA THIS AFTERNOON STEEP LAPSE RATES AND
NEARLY MARCH INSOLATION WILL PROMOTE STRONG SHOWERS WITH SMALL
HAIL OR ICE PELLETS. THUNDERSTORM PARAMETERS ARE WEAK SO WON/T ADD
A MENTION AT THIS POINT...AND SHOW -1C LI AND 50-100 ML CAPE MAINLY
NORTH OF A LINE FROM BURNS TO BOISE TO IDAHO CITY THIS AFTERNOON.
&&
.AVIATION...AFTER 06Z MVFR/IFR CONDITIONS IN SNOW WILL BECOME
WIDESPREAD IN EASTERN OREGON AND THE WEST CENTRAL IDAHO MOUNTAINS...
SPREADING ACROSS SOUTHWEST IDAHO 14Z-18Z ACCOMPANYING AND FOLLOWING
A COLD FRONT. SNOW AND MOUNTAIN OBSCURATION WILL PERSIST THROUGH
WEDNESDAY WITH GRADUAL IMPROVEMENT AFTER 00Z THURSDAY. EAST TO SOUTH
SURFACE WINDS 10-20 KTS WILL INCREASE TO 15-25 KTS AFTER 09Z THEN
SHIFT TO WEST 15-25 KTS AFTER 18Z. WINDS ALOFT WILL BE SOUTHWEST UP
TO 55 KTS AT 10K FEET MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH THURSDAY...LARGE STRONG UPPER LEVEL
SYSTEM MOVING SE TOWARD THE PAC NW THIS AFTERNOON. THIS WILL BRING
WINTER WEATHER TO THE REGION TONIGHT AND TOMORROW. WE HAVE
ADJUSTED THE ADVISORIES THAT WERE ISSUED EARLIER. WE NOW HAVE
WINTER STORM WARNINGS FOR SNOW AND BLOWING SNOW IN EFFECT FOR
BAKER COUNTY AND THE WEST-CENTRAL MOUNTAINS FROM LATE THIS EVENING
INTO TOMORROW MORNING...A WINTER STORM WARNING FOR SNOW FOR THE
WEISER RIVER BASIN FOR THE SAME TIME...A WINTER WEATHER ADVISORY
FOR SNOW FOR THE OWYHEES FOR THE SAME TIME...AND A WINTER WEATHER
ADVISORY FOR THE SOUTHWEST HIGHLANDS FROM 5 AM MST TO 5 PM MST
TOMORROW. THIS SYSTEM IS STRONG BUT RELATIVELY DRY. THEREFORE...
THE MAIN IMPACTS WILL COME FROM WIND-BLOWN SNOW IN BAKER COUNTY
AND IN THE WEST-CENTRAL MOUNTAINS. PEAKS IN THE BOISE MTNS WILL
ALSO BE HEAVILY IMPACTED...BUT AREAS WHERE PEOPLE WILL BE WILL
HAVE MUCH LESS WIND AND THEREFORE NO WARNING WAS ISSUED FOR THE
BOISE MTNS. A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL MOVE
THROUGH THE REGION AS WELL. IT WILL MOVE THROUGH BAKER COUNTY
AROUND 4 AM PST...THROUGH THE REMAINDER OF SE OREGON...THE WEST-
CENTRAL MTNS...AND THE TREASURE VALLEY BETWEEN 6 AM AND 9 AM
MST...AND THROUGH THE BOISE MTNS...SOUTHWEST HIGHLANDS...AND
MAGIC VALLEY BY NOON MST. MOST OF THE PRECIPITATION IN THE HIGHER
ELEVATIONS WILL FALL PRE-FRONTAL DUE TO OROGRAPHIC LIFT. IN THE
LOWER ELEVATIONS...MOST OF THE PRECIPITATION WILL BE ALONG THE
FRONT. IN THE TREASURE VALLEY...THERE WILL BE CONSIDERABLE
SHADOWING BY THE OWYHEES. THIS WILL DRASTICALLY LIMIT SNOWFALL
UNTIL THE FRONT ARRIVES...AND EVEN THEN WE EXPECT JUST A FEW
HUNDREDTHS OF AN INCH OF LIQUID EQUIVALENT. SNOW SHOWERS IN THE
AFTERNOON MAY ADD ANOTHER COUPLE OF HUNDREDTHS...BUT OVERALL VERY
LITTLE IF ANY ACCUMULATION IS EXPECTED IN THE TREASURE VALLEY. IN
THE SOUTHWEST HIGHLANDS...SNOW WILL LINGER IN TO THE AFTERNOON AS
THE FRONT SLOWS AND OROGRAPHIC EFFECTS CONTRIBUTE TO A LONGER
SNOWFALL. TEMPS OVERNIGHT WILL BE MILDER THAN LAST NIGHT DUE TO
CLOUD COVER AND WIND. IN THE TREASURE VALLEY ESPECIALLY... STRONG SE
WINDS WILL KEEP THE TEMPS ABOVE FREEZING...AND THIS WILL MAKE IT
NEARLY IMPOSSIBLE FOR WHAT LITTLE SNOW DOES FALL TO ACCUMULATE ON
THE ROADWAYS IN THE MORNING. HIGHS WED AND THU WILL BE 5 TO 10
DEGREES BELOW NORMAL. SNOW SHOWERS WILL PICK UP AGAIN THU...
ESPECIALLY IN THE SOUTHWEST HIGHLANDS AND IN SOUTHERN TWIN FALLS
COUNTY...AS A SHORT WAVE MOVES THROUGH THE LARGE TROUGH. SNOWFALL
MAY BE ENOUGH FOR NEW ADVISORIES AT THAT TIME.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...MODEL AGREEMENT IS
FAIR THROUGH SUNDAY. THURSDAY NIGHT AND FRIDAY WILL BE CLOUDY AND
SHOWERY AS LOW PRESSURE EXITS TO THE EAST...AND HIGH PRESSURE PUSHES
INLAND TOWARD THE WEST COAST. UPPER LEVEL HEIGHTS WILL BE SLOW TO
BUILD HOWEVER...AND THE AREA WILL REMAIN UNDER UNSETTLED NORTHWEST
FLOW ALOFT THROUGH SATURDAY NIGHT. THIS WILL MAINTAIN A CHANCE OF
PRECIPITATION IN THE CENTRAL MOUNTAINS AS MOISTURE STREAMS IN ATOP
THE RIDGE...WITH CLOUDY CONDITIONS ELSEWHERE. BY SUNDAY ALL AREAS
LOOK TO BE WARM AND DRY...AS THE RIDGE AXIS MOVES OVER THE GREAT
BASIN. BEGINNING MONDAY UNCERTAINTY INCREASES...AND WHILE MODELS ARE
DEPICTING SIMILAR FEATURES...THERE ARE MARKED TIMING AND AMPLITUDE
DIFFERENCES. IT APPEARS THAT A WEAK DISTURBANCE OR COLD FRONT WILL
AFFECT THE AREA SOMETIME EARLY IN THE WEEK...BUT NO OTHER DETAILS
ARE CURRENTLY AVAILABLE. THEREFORE...THIS SYSTEM WILL BE EVALUATED
FURTHER AS WE MOVE CLOSER IN TIME TO THE EVENT. ALL IN ALL...THE
AREA LOOKS TO REMAIN UNDER PROGRESSIVE UPPER LEVEL FLOW...WITH
SYSTEMS MOVING THROUGH EVERY FEW DAYS.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 11 AM MST WEDNESDAY IDZ011-033.
WINTER WEATHER ADVISORY UNTIL 11 AM MST WEDNESDAY IDZ029.
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST WEDNESDAY IDZ015.
OR...WINTER STORM WARNING UNTIL 10 AM PST WEDNESDAY ORZ062.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JT
PREV SHORT TERM...SP
PREV LONG TERM....BB/DD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
340 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIRMASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEWPOINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONGWAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONGWAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* ARRIVAL LOCALLY OF RA AND TS MOVING ENE FM E CENTRAL IA AND W
CENTRAL IL.
* IFR CONDITIONS PERSISTING INTO MID AFTERNOON.
* LLWS TIL MID MORNING.
* STRONG SE WINDS BECOMING SW AND GUSTY BY MID MORNING...INCREASING
TO STRONG WITH G35-45KT LIKELY LATE MORNING WELL INTO AFTERNOON.
TRS
//DISCUSSION...UPDATED 06Z...
A VERY SLOPPY WX PICTURE EVOLVING WITH MULTIPLE WX CONCERNS. A LOW
PRESSURE SYSTEM IS DEEPENING OVER THE UPPER MISSOURI VALLEY WILL
TURN EAST TRACK THROUGH SRN MN/WI TOMORROW. THIS SYSTEM IS DRAWING
MOISTURE NWD FROM THE GLFMEX...AND OVERRUNNING AN ASSOCIATED WARM
FRONT EXTENDING THROUGH SRN IOWA TO SRN IL/IN. WIDESPREAD RAIN HAS
OVERSPREAD THE AREA...WITH THE LATEST RADAR IMAGERY SHOWING MORE
CONVECTIVE ELEMENTS AND SCT TS ALONG AND SOUTH OF THE WARM FRONT.
AT ISSUANCE TIME...CONDITIONS WILL BE APPROACHING MVFR LEVELS AND
EXPECT CIGS/VIS TO DROP TO MVFR BY AROUND MIDNIGHT. THERE WILL BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT ISOLD/EMBEDDED TS...BUT
COVERAGE SHOULD BE SPARSE AND HAVE LITTLE CONFIDENCE ON ANY TIMING
OR DURATION OF TS AT THE TERMINALS. SO...WILL CONTINUE TO LIMIT
THE TS MENTION IN THE TAFS TO JUST VCTS AND CB GROUPS. CONFIDENCE
IS HIGHER ON THE OTHER IMPACTS ON SERVICE IN THE POTENTIAL FOR IFR
CONDITIONS AS THE WARM FRONT LIFTS NWRD THROUGH NRN IL EARLY
TOMORROW MORNING. THERE IS ALSO SOME CONCERN IN THE POSSIBILITY OF
STRONGER...MORE LINEAR TS DEVELOPING WITH THE COLD FRONT PASSAGE.
THE SHORT RANGE MODEL GUIDANCE INDICATES THAT THE COLD FRONT
SHOULD QUICKLY PUSH THROUGH THE AREA TOMORROW MORNING BTWN 12-16Z.
THERE ARE INDICATIONS OF THE POTENTIAL FOR INCREASED SURFACE BASED
INSTABILITY AND A WARM SECTOR ENVIRONMENT PUSHING QUICKLY THROUGH
THE AREA BETWEEN THE TIME THAT THE WARM FRONT LIFTS TO THE NORTH
AND THE COLD FRONT SWEEPS EWD ACROSS IL/IN. THIS WOULD PROVIDE A
BRIEF WINDOW OF OPPORTUNITY FOR STRONGER TS TO DEVELOP...BUT
CONFIDENCE IN TIMING IS LOW. FOLLOWING THE PASSAGE OF THE SFC COLD
FRONT...DRY AIR ALOFT WILL OVERRIDE A MOIST LAYER BLW 5KFT...SO A
PERIOD OF DZ WITH IFR CIGS/VIS IS LIKELY THOUGH ARND 18Z. ALSO
FOLLOWING THE FROPA...WINDS WILL VEER SWLY AND QUICKLY STRENGTHEN
THROUGH THE MORNING...WITH GUSTS OF 35KT...OR POSSIBLY
HIGHER...ARE EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.
BY LATE TOMORROW EVENING...WRAPAROUND MOISTURE AND CYCLONIC FLOW
ALOFT ALONG WILL COOLER AIR FILTERING INTO THE AREA BEHIND THE
EXITING LOW WILL BRING BACK MVFR CIGS AND SOME LIGHT SNOW. WITH
THE COLD CORE UPPER LOW MOVING OVER SRN WI DURG THE
EVENING...THERE MAY BE ENOUGH INSTABILITY FOR SOME HEAVIER SNOW
SHOWERS OR GRAUPEL WITH THE LIGHT SNOW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN LLWS EARLY THIS MORNING.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATER TODAY.
* MEDIUM CONFIDENCE IN CIG/VIS TRENDS.
* MEDIUM CONFIDENCE IN PRECIP BEGINNING AND ENDING TIMES.
* MEDIUM CONFIDENCE TS WILL BE ISOLD OR FEW PREDAWN TO DAWN
ACROSS ORD AND MDW AREA.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR. WX NIL.
FRIDAY...MVFR CIGS/VIS. RAIN OR A RAIN/SNOW MIX LIKELY DURING THE
DAY...CHANCE OF LIGHT SNOW AT NIGHT.
SATURDAY...VFR...SLIGHT CHANCE OF LIGHT SNOW OR FLURRIES EARLY...STRONG
GUSTY GUSTY W WINDS IN THE AFTERNOON.
SUNDAY...VFR. SLIGHT CHANCE LIGHT SNOW EARLY.
MONDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...8 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1159 PM CST TUE FEB 28 2012
.DISCUSSION...
ISSUED 856 PM CST TUE FEB 28 2012
SHOWERS AND THUNDERSTORMS HAVE MOVED INTO/EXPANDED ACROSS THE
FORECAST AREA AS A WARM FRONTAL ZONE HAS BEEN PUSHING IN FROM THE
SOUTHWEST. EXPECT THIS TREND TO PERSIST FOR AT LEAST THE NEXT FEW
HOURS. THEN...CHANCES WILL INCREASE AGAIN LATER TONIGHT AS A COLD
FRONT PUSHES IN BEHIND THE WARM FRONT. VIGOROUS THUNDERSTORM
DEVELOPMENT IS OCCURRING ACROSS THE COLD FRONT AT THE
MOMENT...THOUGH THERE IS STILL CONSIDERABLE DOUBT ABOUT THE RISK
OF THESE STRONG STORMS MAKING IT THIS FAR EAST. STILL EXPECT A
DOWNWARD TREND IN THE STORMS BEFORE THEY REACH HERE DUE TO THE
LESS FAVORABLE TIME OF DAY. ALSO...BY THE TIME ANY LINGERING
STORMS GET HERE...THEY SHOULD BE INCREASINGLY ELEVATED.
STILL...WILL NEED TO KEEP AN EYE ON THE SEVERE WIND THREAT WITH
MODELS STILL SUGGESTING A 60-70 KT LOW LEVEL JET AT 850 MB JUST
AHEAD OF THE FRONT.
GOING FORECAST IS IN GOOD SHAPE OVERALL. ONLY MINOR TWEAKS ARE
ANTICIPATED FOR THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 1159 PM CST TUE FEB 28 2012
INITIAL WAVE OF SHOWERS/STORMS FOR THE CENTRAL ILLINOIS TERMINALS
HAS ENDED FOR THE MOST PART...LEAVING MAINLY MVFR CONDITIONS.
ANOTHER COUPLE HOUR PERIOD OF SHOWERS/STORMS POSSIBLE LATE TONIGHT
ALONG THE COLD FRONT...WHICH COULD PRODUCE IFR CONDITIONS.
THEN...VFR CONDITIONS AND GUSTY SOUTHWEST WINDS EXPECTED BEHIND THE
FRONT FOR WEDNESDAY. WIND GUSTS WILL EXCEED 40 KTS AT TIMES FOR
THE DAYTIME HOURS.
BAK
&&
.PREV DISCUSSION...
ISSUED 257 PM CST TUE FEB 28 2012
MAIN CHALLENGES WITH THIS FORECAST PACKAGE ARE WITHIN THE
SHORT-TERM...AS TWO SEPARATE STORM SYSTEMS ARE EXPECTED TO IMPACT
CENTRAL ILLINOIS OVER THE NEXT COUPLE OF DAYS.
SHORT TERM...TONIGHT THROUGH FRIDAY
LOW PRESSURE DEVELOPING IN THE LEE OF THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER MIDWEST TONIGHT...SPREADING SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL ILLINOIS. AIRMASS IS INITIALLY
QUITE DRY...AS EVIDENCED BY 20Z SURFACE DEWPOINTS IN THE MIDDLE
TO UPPER 20S...THEREFORE ONSET OF PRECIP WILL LIKELY HOLD OFF
UNTIL MID TO LATE EVENING...WHEN WINDS BEGIN TO VEER TO A MORE
SOUTHERLY DIRECTION AND LOW-LEVELS MOISTEN. ONCE DEEPER MOISTURE
ARRIVES...SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP ACROSS THE
AREA IN ADVANCE OF A WARM FRONT. ALL MODELS PUSH THIS PRECIP
EASTWARD INTO INDIANA OVERNIGHT...AS THE ENTIRE KILX CWA PUNCHES
INTO THE WARM SECTOR OF THE STORM SYSTEM.
NEXT QUESTION WILL BE HOW MUCH CONVECTION WILL DEVELOP ALONG THE
APPROACHING COLD FRONT LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
HIGH-RES MODELS SUCH AS THE HRRR AND 4KM WRF-NMM SUGGEST A BROKEN
LINE OF STORMS FORMING ALONG THE FRONT AND PUSHING INTO ILLINOIS
AFTER 09Z. FORECAST SOUNDINGS REVEAL A HIGH DEGREE OF LOW-LEVEL
WIND-SHEAR NEAR THE WARM FRONT...HOWEVER ELEVATED INSTABILITY
APPEARS TO BE RATHER MINIMAL. DESPITE MODEST INSTABILITY...VIGOROUS
UPPER DYNAMICS AND STRENGTHENING 850MB JET WILL BE MORE THAN ENOUGH
TO TRIGGER THUNDERSTORMS ALONG THE COLD FRONT TOWARD DAWN WEDNESDAY.
SEVERE THREAT WILL BE LIMITED DUE TO STABLE SURFACE-BASED
LAYER...HOWEVER THINK A FEW STORMS WILL BE STRONG ENOUGH TO MIX
HIGHER MOMENTUM AIR DOWN TO THE SURFACE PRODUCING MARGINALLY
SEVERE WIND GUSTS. PRIMARY TIME FRAME FOR SEVERE POTENTIAL WILL BE
BETWEEN 3 AM AND 9 AM.
COLD FRONT WILL PUSH EASTWARD INTO INDIANA BY AROUND MIDDAY...ENDING
ANY THREAT FOR MORNING SHOWERS/STORMS. DUE TO STRONG SOUTHERLY
FLOW AHEAD OF THE BOUNDARY...HIGH TEMPS WILL SURGE WELL INTO THE
60S ACROSS MUCH OF THE AREA...AND MAY EVEN REACH THE 70 DEGREE MARK
ACROSS THE FAR SOUTHEAST CWA. ONCE THE FRONT PASSES...READINGS WILL
LIKELY FALL A FEW DEGREES DURING THE AFTERNOON. BIG STORY ON
WEDNESDAY WILL BE THE VERY STRONG WINDS...AS PRESSURE GRADIENT
TIGHTENS BETWEEN EXITING FRONT AND APPROACHING HIGH PRESSURE.
SUSTAINED WINDS WILL INCREASE INTO THE 20 TO 30 MPH RANGE...WITH
GUSTS POTENTIALLY EXCEEDING 40 MPH.
QUIET WEATHER WILL BE ON TAP FOR THURSDAY...AS HIGH PRESSURE
DRIFTING OVERHEAD BRINGS CLEAR SKIES AND LIGHT WINDS. THE BREAK IN
THE ACTION WILL BE SHORT-LIVED HOWEVER...AS NEXT UPPER TROUGH
QUICKLY DIGS ACROSS THE WESTERN CONUS AND SURFACE LOW PRESSURE
ONCE AGAIN FORMS IN THE LEE OF THE ROCKIES. MODELS HAVE BEEN
STRUGGLING WITH THE TRACK OF THIS SYSTEM FOR THE PAST FEW
DAYS...AND THE 12Z 28 FEB SUITE IS NO EXCEPTION. THE NAM CONTINUES
TO BE THE FURTHEST EAST WITH THE LOW TRACK...TAKING IT FROM
NORTHERN ARKANSAS AT 12Z FRI TO CENTRAL INDIANA BY 18Z FRI.
ON THE OTHER HAND...THE GFS IS FURTHEST WEST...POSITIONING THE LOW
NEAR QUINCY ILLINOIS BY 18Z FRI. MEANWHILE...THE ECMWF REPRESENTS
A COMPROMISE BETWEEN THE TWO TRACKS AND HAS BEEN THE MOST
CONSISTENT SOLUTION OVER THE PAST FEW RUNS. AS A RESULT...HAVE
TRENDED TOWARD THE ECMWF WITH THE LATE WEEK STORM SYSTEM.
WITH LOW PRESSURE TRACKING ACROSS CENTRAL/EAST-CENTRAL ILLINOIS
DURING THE DAY FRIDAY...SHOWERS AND A FEW THUNDERSTORMS WILL BE
LIKELY. GIVEN EXPECTED TRACK...HAVE FOCUSED THUNDER ACROSS THE
EASTERN TWO-THIRDS OF THE CWA...WHILE KEEPING THE ILLINOIS RIVER
VALLEY ON THE COOL SIDE OF THE SYSTEM AND CONVECTION FREE. AS THE
LOW LIFTS INTO THE GREAT LAKES...W/NW WINDS WILL BRING COLDER AIR
INTO THE REGION BY FRIDAY NIGHT. LINGERING RAIN SHOWERS DURING THE
EVENING MAY CHANGE TO SNOW-SHOWERS OVERNIGHT...HOWEVER NO
ACCUMULATION IS ANTICIPATED.
LONG TERM...SATURDAY THROUGH TUESDAY
COOL/TRANQUIL WEATHER IS IN STORE FOR THE WEEKEND...AS UPPER TROUGH
DIGS OVER THE EASTERN CONUS. WEAK SHORT-WAVE WILL SLIDE
SOUTHEASTWARD INTO THE REGION ON SUNDAY...HOWEVER MOISTURE WILL BE
EXTREMELY LIMITED...SO DO NOT ANTICIPATE ANY PRECIP. THE TROUGH
WILL GRADUALLY SHIFT FURTHER EASTWARD EARLY NEXT WEEK...ALLOWING A
WARMING TREND TO GET UNDERWAY BY MONDAY AND TUESDAY. THE NEXT
SIGNIFICANT STORM SYSTEM WILL LIKELY HOLD OFF UNTIL THE MIDDLE OR
END OF NEXT WEEK...SO DRY WEATHER IS EXPECTED THROUGH THE ENTIRE
EXTENDED.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM TO 6 PM CST WEDNESDAY FOR ILZ027>031-
036>038-040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
333 AM CST WED FEB 29 2012
.SYNOPSIS...
WATER VAPOR IMAGERY IN CONJUNCTION WITH LATEST RUC PROGS SHOW A
CLOSED H5 LOW OVER SERN SD WITH A NEGATIVELY TILTED TROF EXTENDING
SOUTHEAST THROUGH IA AND CENTRAL IL. AT THE SURFACE DEEP LOW
PRESSURE WAS OVER NW IA WITH AN OCCLUDED FRONT EXTENDING SE
THROUGH CENTRAL IA. A WARM FRONT BRANCHED OFF TO THE EAST INTO IL
AND THE COLD FRONT ARCED SOUTH AND WEST THROUGH MO. THE MAIN AREA
OF TSRA AHEAD OF THE SYSTEM WAS JUST EXITING THE EASTERN CWFA AT
09Z. ANOTHER SHORT LINE OF SHRA/ISOLD TSRA HAD RECENTLY DEVELOPED
NORTH OF THE OCCLUSION IN CENTRAL IA AND WAS LIFTING NORTHEAST
THROUGH THE FAR NW CORNER OF THE CWFA. TEMPERATURES IN THE LOW 50S
WERE AS FAR NORTH AS I80 ALONG AND EAST OF THE MS. READINGS WERE
STILL AROUND 40 OVER THE NORTHERN.
&&
.SHORT TERM...TODAY AND TONIGHT...
THE STACKED SYSTEM WILL TRACK EAST ALONG THE IA/MN BORDER TODAY
AND THEN ON INTO SWRN ONTARIO BY THURSDAY MORNING. HIGH PRESSURE
WILL FILL IN BEHIND THE STORM WITH A SURFACE RIDGE EXPECTED TO
MOVE INTO CENTRAL IA BY THURSDAY MORNING.
FOR TODAY ALL OF THE SHRA/TSRA WILL BE OUT OF THE FORECAST AREA AND
CLEARING VIA THE DRY SLOT SHOULD SPREAD OVER THE SOUTHERN HALF OF
THE CWFA BY 12Z. WITH THE STRONG PRESSURE GRADIENT AROUND THE
SURFACE LOW AND MORNING SUN THE SOUTHERN HALF OF THE AREA SHOULD
BE ABLE TO MIX OUT FAIRLY DEEP...AT LEAST TO 800MB...BEFORE WRAP
AROUND ST SAGS SOUTH OVER THE AREA BY LATE MORNING OR EARLY
AFTERNOON. MODELS SOUNDINGS SHOW THE DEEP MIXING WILL BE ABLE TO
TAP WINDS OF 45 TO 50KTS DURING THE AFTERNOON. WITH LITTLE
DIRECTIONAL CHANGE IN THE MIXED LAYER THERE SHOULD BE EFFICIENT
MOMENTUM TRANSPORT TO THE SURFACE CAUSING WINDS TO GUST 40 TO 50
MPH LATE THIS MORNING AND THIS AFTERNOON. EXPECT AREAS SOUTH OF
I80 TO HAVE THE STRONGEST WINDS. LESS HEATING AND THICKER CLOUD
COVER OVER NORTHEAST SHOULD KEEP GUSTS FROM EXCEEDING ADVISORY
CRITERIA. THEREFORE...NO CHANGES ARE PLANNED FOR THE CURRENT
ADVISORY. IN ADDITION TO THE WIND ISSUES SOME SCATTERED RAIN
AND/OR SNOW SHOWERS WILL REDEVELOP OVER THE NRN HALF OF THE AREA
WITH THE RAIN CLOSE TO HIGHWAY 30 AND THE SNOWSHOWERS ALONG THE
HIGHWAY 20 CORRIDOR. THE PRECIP WILL BE LIGHT AND LITTLE IF ANY
SNOW ACCUMULATION IS EXPECTED. SINCE THE SHOWERS WILL BE TIED TO
INSTABILITY FROM DAYTIME HEATING...THEY SHOULD DISSIPATE BY EARLY
THIS EVENING. TEMPERATURES IN THE NORTH SHOULDN/T RISE MUCH TODAY
WITH CLOUDS OVER AREA THROUGH THE DAY. IN THE SOUTH READINGS
SHOULD REBOUND TO AROUND 50 WITH SOME MORNING SUN AND THE DEEPER
MIXING.
TONIGHT WITH THE STORM MOVING AWAY FROM THE REGION THE LOW LEVEL
CYCLONIC FLOW WILL WEAKEN AND SUBSIDENCE SHOULD BE ABLE TO EAT
AWAY AT THE WRAP AROUND ST OVER THE WESTERN AND SOUTHERN CWFA. THE
NORTHEAST MAY HOLD ON TO CLOUDS THROUGH 12Z. LOWS TONIGHT AROUND
30 LOOK REASONABLE.
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. THURSDAY NIGHT...THE MODELS BRING AN INITIAL
WAVE OF LOW PRESSURE THROUGH THE AREA ALONG A FRONT/BOUNDARY.
INTERESTINGLY...SEVERAL OF THE MODELS ARE BREAKING OUT LIGHT QPF
OVER THE NORTHERN HALF OF THE CWFA. INTERNALLY...FORCING IS
GENERALLY WEAK...MOISTURE IS LACKING...AND CONDENSATION PRESSURE
DEFICITS REMAIN FAIRLY HIGH. MOISTURE/SPEED CONVERGENCE CAN BE
IMPLIED BY THE INVERTED TROF BUT INTERNALLY THE MODELS GENERALLY
HAVE EITHER NO CONVERGENCE OR IT MOVES NORTH/EAST OF THE CWFA.
THE INVERTED TROF IS THE MOST TROUBLING AS THEY ARE NOTORIOUS FOR
SURPRISES. SO...AFTER WEIGHING THE OPTIONS HAVE OPTED TO GO WITH
SCHC POPS OVER ROUGHLY THE NORTHERN THIRD WHICH CONCEPTUALLY IS THE
MOST LIKELY AREA TO SEE ANY PRECIP. PTYPE SHOULD BE SPRINKLES OR A
VERY LIGHT RAIN AS WET BULB TEMPERATURES ARE ABOVE FREEZING AT THE
SFC AND AT 0.5KM.
THE MAIN WAVE OF ENERGY ARRIVES ON FRIDAY. BASED ON THE OVERALL
FORCING THE SOUTHEAST HALF OF THE CWFA HAS THE BETTER CHANCES FOR
PRECIPITATION. WET BULB TEMPERATURES SLOWLY FALL DURING THE DAY SO
THE PRECIPITATION WILL INITIALLY START OUT AS RAIN. BY MID TO LATE
FRIDAY AFTERNOON WET BULB TEMPERATURES DROP ENOUGH AT 0.5KM THAT A
RAIN/SNOW MIX SHOULD DEVELOP OVER THE NORTHWEST THIRD TO HALF OF THE
CWFA. A RAIN/SNOW MIX SHOULD BE SEEN ACROSS MOST OF THE CWFA FRIDAY
EVENING WITH PRECIPITATION ENDING AFTER MIDNIGHT.
SATURDAY ON...
MODEL CONSENSUS GIVE DRY CONDITIONS ON SATURDAY AHEAD OF AN
APPROACHING CLIPPER SYSTEM. SATURDAY NIGHT/SUNDAY THE CONSENSUS GIVE
SCHC POPS OVER THE NORTHEAST THIRD TO HALF OF THE CWFA. RIGHT NOW
THIS LOOKS REASONABLE GIVEN MOISTURE AVAILABILITY AND THE OVERALL
DISAGREEMENT ON TIMING. HOWEVER...GIVEN THE OVERALL SYNOPTIC SETUP
THESE POPS ARE PROBABLY TOO LOW.
MODEL CONSENSUS GIVES DRY CONDITIONS SUNDAY NIGHT THROUGH TUESDAY AS
HEIGHTS BUILD OVER THE MID CONUS AHEAD OF SHORTWAVE ENERGY ARRIVING
IN THE PAC NW. STRONG SOUTHERLY FLOW IS PROGGED TO DEVELOP AHEAD OF
ANOTHER STORM SYSTEM IN THE NORTHERN PLAINS MONDAY AND TUESDAY. THE
MODELS ARE LIKELY UNDER ESTIMATING THE SURGE OF WARM AIR COMING
NORTH BASED ON THE OVERALL SYNOPTIC SET UP. TEMPERATURES TUESDAY
SHOULD BE WELL ABOVE NORMAL AND POTENTIALLY HIGHER THAN WHAT THE
MODELS CURRENTLY SUGGEST.
..08..
&&
.AVIATION ISSUED AT 1138PM CST TUE FEB 28 2012...
A STRONG STORM SYSTEM MOVING INTO SOUTHERN MINNESOTA WILL BRING
RAIN AND SCATTERED THUNDERSTORMS ACROSS THE FORECAST TERMINALS
UNTIL 10Z. GENERALLY MVFR CONDITIONS DUE TO LOW CLOUDS BASES OF
1-3K AGL ARE EXPECTED UNTIL A COLD FRONT PASSES BETWEEN 11-14Z
WHEN VFR CONDITIONS RETURN. THE POTENTIAL FOR THUNDERSTORMS THE
NEXT SEVERAL HOURS IS TOO REMOTE AT ANY GIVEN SITE TO MENTION
BEYOND USE OF CB WORDING. SOUTHEAST WINDS OF 15 TO 25 KTS WILL
SHIFT TO THE WEST SOUTHWEST AND INCREASE TO 25 TO 35 KTS WITH SOME
HIGHER GUSTS TO 40 KTS BETWEEN 15-23Z. LOW CLOUDS WILL RETURN FROM
NORTH TO SOUTH AT ALL TERMINALS BETWEEN 20-24Z WITH SNOW SHOWERS
POSSIBLE AT CID AND DBQ. WINDS WILL SLIGHTLY DECREASE TO 20 TO 30
KTS AFTER SUNSET. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR BENTON-BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-HENRY
IA-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR BUREAU-HANCOCK-HENDERSON-HENRY IL-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-WARREN-WHITESIDE.
MO...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1258 AM EST WED FEB 29 2012
.Update...
Update#2
Issued at 945 PM EST Feb 28 2012
A line of thunderstorms has developed across southeast MO and
southern IL. Timing of this line brings it into the western portion
of the forecast area around 05Z. Mesoscale models continue to
develop more convection overnight as the low level jet ramps up.
Have made only minor adjustments to the ongoing forecast.
Update#1
Issued at 630 PM EST Feb 28 2012
The latest runs of the HRRR and the Rapid Refresh are indicating a
bit later start to the precipitation this evening. Currently there
is nothing much on radar close to the forecast area. Will therefore
take out/lower pops before the 05-06Z time frame. Temperatures are
also running quite a bit warmer than hourlies so will update to
bring them in line. Updates will be out soon.
.Short Term (Tonight through Wednesday night)...
Updated at 200 PM EST Feb 28 2012
...Heavy rain/strong storms tonight with potential for severe storms
tomorrow...
The much anticipated storm system that will affect us in the short
term is currently developing over Nebraska, with it`s warm front and
60+ dewpoints slowly filtering northward across the southern CONUS,
and it`s cold front just downstream of the Rockies. Looks like with
the 12z runs of the mesoscale models, think precipitation will come
in two main waves. First, with the warm-air advection/elevated
showers/storms overnight ahead of the warm front. And second, along
of and just ahead of the cold front tomorrow afternoon.
Tonight, clouds and moisture will be on the increase tonight as the
surface low develops and moves towards the Upper Midwest overnight.
This will help draw the warm front from southwest to northeast
across our County Warning Area (CWA), mainly from the 07-13z time
frame. Showers and thunderstorms should develop along the nose of a
65-70 kt low-level jet, which will overspread north of and ahead of
the warm front from SW to NE across the CWA. However, best moisture
convergence seems to be across our northwest CWA after 06z, so think
convection will be rather scattered from 00-06z tonight, and will
blow up ahead of the warm front, mainly hugging the Ohio River and
into north-central Kentucky from 06-12z. At this time, our far
southwestern CWA could see surface-based warm-sector air, but not
sure any of the convection will be that far south to be rooted in
the boundary layer air. Thus, think the severe chances tonight are
fairly slim. However, if storms do lag into central and even
south-central KY in the morning (4-8am CST), these will likely be
surface-based, and a severe threat would be possible, with damaging
winds and possibly an isolated tornado threat but think that is slim
right now. These storms look more like heavy rainers, possibly
hailers, and ample lightning. And again, think the concentration
will mainly be across the central part of the CWA northward or
northwestward.
Then after daybreak, warm-air advection convection should more north
of the CWA, with the entire CWA getting rooted into the boundary
layer/warm-sector air. Not sure we`ll see a break in the low
strato-cu, but it is possible. If breaks occur, much of the
low-level jet winds will mix down, creating ample gusty winds
tomorrow. Think sustained winds of 20-25 mph will be possible with
gusts as high as 40 mph, close to wind advisory criteria. May defer
that to the next forecast tonight. Either way, we`ll be sectored in
the warm, moist, gusty air ahead of the quickly approaching cold
front. Progged soundings show ample deep-layer shear, and strong
speed shear in the low-levels. Deep moisture along the cold front
however will be much lower than the overnight moisture, so think a
few storms will erupt along the cold front, but not a large, thick
line of convection. However, any storm that develops along the cold
front has the potential to become quickly supercellular, with
damaging winds, hail and isolated tornadoes being potential threats.
Best chance for this would be east of I-65 after noon tomorrow.
There will still be a severe weather threat along the cold front
west of I-65 as well, but the best heating and longer time to
recover from morning convection will happen over the eastern CWA.
So overall, looks like the best chance for severe weather will be a
small window over our southwestern CWA after 4am CST late tonight,
but a better chance mainly along and east of I-65 tomorrow
afternoon. Behind the cold frontal passage, winds will veer around
to the west and continue to be gusty until Wednesday night where
they will taper off.
Lowered precipitation in the grids to account for the break between
late night/early morning warm frontal convection and the lesser
amount but more significant strong-severe convection tomorrow
midday-afternoon.
Concerning temps, lows will drop off early tonight and then increase
towards 12z with the warm front pushing northward. Tomorrow, despite
mostly cloudy conditions, temperatures will still be able to rise
into the 60s and even lower 70s over the south/southeast.
.Long Term (Thursday - Tuesday)...
Updated at 315 PM EST Feb 28 2012
...Potential for more strong to severe thunderstorms again Friday
afternoon and night...
Another potent storm system on Friday is the main concern in the
extended forecast. Before that occurs, however, Thursday will be a
tranquil weather day between systems. Surface high pressure over the
Ohio Valley and Southeast will ensure a mostly sunny day, and
temperatures will remain mild with afternoon highs generally in the
lower and mid 60s.
The high will move off to our east quickly Thursday night as a
deepening trough aloft takes shape over the western United States
and begins moving east. The trough will cause CYCLOGENESIS across
the southern high Plains Thursday night. The surface low pressure
center will then deepen quite rapidly as it moves northeast into the
mid
Mississippi Valley Friday and Great Lakes Friday night. Ahead of
this low, low-level moisture should return rapidly. Last night`s and
the newest 12z model runs suggest an area of precipitation will
quickly develop Thursday night over the Tennessee Valley in a warm
advection/isentropic lift zone. Elevated instability returning from
the southern Plains suggests that thunder will be embedded within
the area of rain. This precipitation may make it into south-central
KY by Friday morning, then lift quickly northeast into eastern KY in
the afternoon.
The main concern is Friday afternoon and evening, according to the
latest model timing. Wind fields increase throughout the lower and
mid levels, while actually decent instability is forecast to develop
in the warm sector between the departing warm front and east of a
potent cold front, which will extend south from the low pressure
center. Given cold frontal forcing, wind fields, and instability,
strong to severe storms could develop over parts of the Ohio Valley
extending south into the Tennessee Valley and lower Mississippi
Valley/southeastern United States. This system will need to be
watched closely.
Much cooler weather will move in for the weekend. The strong cyclone
mentioned above will move north of the Great lakes, with possibly a
surface pressure under 980mb. It parent 500mb trough will be
absorbed by a strengthening polar vortex near Hudson`s Bay. By early
Sunday, ridging will strengthen over the Rockies with troughing over
the Great Lakes. Expect a partly cloudy sky Saturday with brisk west
winds developing during the afternoon. Highs Saturday will remain in
the lower to mid 50s. A weak clipper will scoot southeast from the
Upper Missouri Valley Saturday and traverse the Commonwealth on
Sunday. Cloud cover will increase Sunday with just a slight chance
of showers. Highs Sunday will have a hard time reaching 50.
In a slowly progressive pattern, 500mb ridging will move east across
the central plains on Monday. After partly cloudy, cool day Monday
with high pressure nearly overhead, southwest winds will commence
Tuesday, beginning a warmup.
&&
.Aviation (06Z TAF Issuance)...
Updated at 1225 AM EST Feb 29 2012
Warm front just south of KSDF at this hour. Have some thunderstorms
riding north of that boundary and otherwise look like we have more
airmass type showers that may spark off some thunder as the plenty
of moisture streams in from the southwest. So far the near-surface
air has not been moist enough to produce much in the way of vsby
restrictions, except in the heaviest storms. Have backed off on the
prevailing storm conditions and tried to time the first 6 hours of
this TAF based on radar. After that expect a brief dry period before
another round of storms comes in closer to a cold front later this
morning into the afternoon.
With regard to winds, should have low-level shear through around
daybreak at all of the sites. After daybreak, surface winds will
become gusty from the southwest, with peak gusts of 25-35 kts. May
even get some higher values if we get enough sunshine to mix higher
up.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AL
Long Term........JSD
Aviation.........EER
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1253 AM EST WED FEB 29 2012
.UPDATE...
ISSUED AT 1253 AM EST WED FEB 29 2012
NO MAJOR CHANGES NEEDED AT THIS EARLY HOUR. HAVE SPED UP THE
ARRIVAL TIME OF INITIAL BATCH OF MAINLY LIGHT SNOW PER RADAR
TRENDS...WITH SECONDARY HEAVIER BATCH OF PRECIP EXPECTED TO BEGIN
OVERTAKING THE CWA AFTER 09Z. GIVEN UPSTREAM OBS...HAVE ALSO
INTRODUCED MIXED PRECIP MENTION EARLIER ACROSS THE SOUTHWEST
COUNTIES. UPSTREAM RADAR PICS OVER GREEN BAY HAVE A MIXED
PRECIP/CELLULAR APPEARANCE TO THEM...IN LINE WITH LATEST RUC PROGS
BRINGING IN A PRONOUNCED WARM NOSE UP TO +3C INTO THE SOUTHWEST
COUNTIES ROUGHLY 09-10Z. WILL CUT BACK SNOWFALL TOTALS DOWN THAT
WAY A BIT (MAINLY 1-2 INCHES)...BUT HAVE ALSO RAISED AMOUNTS
ACROSS THE HIGHER TERRAIN AREAS WHERE UPSLOPE COMPONENT SHOULD
KEEP COLDER AIR LOCKED IN LONGER THROUGH MID MORNING. CURRENT
HEADLINES LOOK JUST FINE...BUT WILL HAVE TO WATCH PRECIP TYPE AS
HEAVY AXIS OF QPF ARRIVES THROUGH MID MORNING. IF TYPE REMAINS
ALL SNOW...CAN FORESEE THE NEED TO EXPAND THE WARNING MORE INTO
NORTHWEST LOWER BETWEEN M-72 AND M-32. HOWEVER...CONCERNED THAT
WARM NOSE WILL ARRIVE IN THOSE AREAS QUICKLY AS IS TYPICAL IN
THESE SITUATIONS...CUTTING INTO SNOWFALL AMOUNTS. ALL IN ALL...NO
MATTER THE SPECIFICS...IT WILL BE A MESSY MORNING COMMUTE IN MANY
AREAS SOUTH OF THE BRIDGE.
UPDATE ISSUED AT 1035 PM EST TUE FEB 28 2012
HAVE UPGRADED SOME COUNTIES IN NORTHERN LOWER MICHIGAN TO A
WARNING.
LOW PRESSURE NOW ADVANCING THROUGH EASTERN IOWA AHEAD OF A VERY
VIGOROUS UPPER LEVEL SHORT WAVE EJECTING NORTHEASTWARD FROM THE
CENTRAL PLAINS. VERY STRONG PULSE OF WARM ADVECTION FORCING/MOISTURE
FEED STARTING TO TAP THE GULF LEADING TO TO A LARGE EXPANDING
SHIELD OF PRECIP FROM ILLINOIS UP ACROSS WISCONSIN/MINNESOTA AND
THE DAKOTAS. STRONG CONVECTION BREAKING OUT IN THE CENTRAL PLAINS.
PRETTY MUCH YOUR TYPICAL STRONG SPRING STORM.
ACROSS THE REGION...A PRETTY HEFTY BATCH OF SNOWFALL HAS ALREADY
BLOSSOMED OVER SRN/ERN WISCONSIN THIS EVENING AND ABOUT TO WORK
INTO THE SW PART OF THIS CWA. BUT THE STRONGEST FORCING IS YET TO
ARRIVE...
OVERNIGHT...LOW PRESSURE SYSTEM WILL OCCLUDE OVER THE
IOWA/MINNESOTA REGION OVER THE NEXT SEVERAL HOURS. AS THIS
OCCURS...VERY STRONG PULSE OF WARM ADVECTION FORCING AND
ASSOCIATED WING OF PRECIP WILL ADVANCE UP THROUGH LOWER MICHIGAN
OVERNIGHT AND UP INTO EASTERN UPPER MICHIGAN WEDNESDAY
MORNING...FOLLOWED BY A SHARP DRY PUNCH OF AIR WORKING THROUGH THE
CWA DURING THE AFTERNOON. PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST THINKING.
INITIALLY...WAS SKEPTICAL OF NAM/GFS QPF AMOUNTS APPROACHING ONE
INCH BY WEDNESDAY EVENING WITH THIS STORM...ESPECIALLY GIVEN THAT
BULK OF PRECIP WILL ONLY LAST AROUND 6 HOURS BEFORE TAPERING OFF
SHARPLY TO DRIZZLE/FREEZING DRIZZLE WITHIN THE DRY SLOT DURING THE
AFTERNOON HOURS. HOWEVER...MODEL N-S CROSS SECTIONS ACROSS LOWER
MICHIGAN HAVE CHANGED MY MIND. VERY IMPRESSIVE F-GEN DEVELOPS
ACROSS THE REGION WEDNESDAY MORNING WITHIN THE SHARPLY CYCLONIC
FLOW AND VERY STRONG WIND CORE THAT WORKS UP THROUGH THE REGION.
RESULTING OMEGA BULLSEYE IS IMPRESSIVE...MAXIMIZING IN THE DGZ
RIGHT UP ACROSS NRN LOWER MICHIGAN FOR A TIME WEDNESDAY MORNING.
TERRAIN AND A STRONG SE LOW LEVEL FLOW WILL LIKELY HELP THE CAUSE
OVER NE AND NORTH CENTRAL LOWER MICHIGAN AS WELL.
GIVEN THAT...AND A SLIGHTLY SLOWER TREND IN THE 00Z GUIDANCE SUGGESTING
MORE PRECIP OVER NRN LOWER MICHIGAN...HAVE EXPANDED WARNING DOWN
TWO TIER OF COUNTIES IN NRN LOWER MICHIGAN. HAVE TENTATIVELY LEFT
OUT CHARLEVOIX/ANTRIM COUNTIES AS DOWNSLOPING SE FLOW MAY KEEP PRECIP
IN CHECK...WILL SEE. STILL NOT CONVINCED WE SEE AN INCH OF LIQUID
WITH THIS SYSTEM. BUT EVEN IF WE GET CLOSE...ACCUMULATIONS IN THE
4 TO 7 INCH RANGE CERTAINLY VERY POSSIBLE OVER PORTIONS OF NE
LOWER MICHIGAN.
PRECIP TYPE ISSUES REMAIN WITH THIS SYSTEM...AS ABOVE FREEZING
WARM NOSE SURGES UP INTO NRN LOWER MICHIGAN ON WEDNESDAY.
BUT...TIMING IS EVERYTHING...AND BULK OF PRECIP ACROSS THE CWA
WILL BE LARGELY OVER BEFORE THE WARM NOSE ARRIVES. SO AT THIS
POINT...AM NOT TOO CONCERNED ABOUT SIGNIFICANT ICING OR PRECIP
CHANGING TO RAIN...AT LEAST DURING THE HEAVIEST PART OF THE EVENT.
UPDATE ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1208 AM EST WED FEB 28 2012
LOW PRESSURE OVER THE MIDWEST WILL ADVANCE INTO THE WESTERN GREAT
LAKES ON WEDNESDAY...AND THEN SLOWLY MOVE THROUGH LOWER MICHIGAN
WEDNESDAY NIGHT. AHEAD OF THE LOW...FIRST ROUND OF PRECIP STARTING
TO WORK INTO THE NRN LOWER MICHIGAN AND WILL OVERSPREAD THE
TERMINAL SITES...SOUTH THROUGH NORTH...THROUGHOUT THE OVERNIGHT
HOURS. AS THIS OCCURS...CONDITIONS WILL DETERIORATE TO IFR BY
MORNING (SEE TAFS FOR TIMING DETAILS).
ROUND OF FAIRLY HEAVY PRECIP (MAINLY SNOW) WILL IMPACT NRN LOWER
MICHIGAN WEDNESDAY MORNING BEFORE TAPERING OFF TO LIGHT SNOW/DRIZZLE
OR FREEZING DRIZZLE...SOUTH-NORTH DURING THE AFTERNOON...AS MID
LEVEL DRY SLOT ADVANCES UP THROUGH THE REGION. LOW CIGS/VSBYS WILL
REMAIN HOWEVER.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS THROUGH MUCH OF
THE DAY.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MIZ019>021-025>027-031>036-041-042.
WINTER STORM WARNING FROM 4 AM EARLY THIS MORNING TO 5 AM EST
THURSDAY FOR MIZ016>018-022>024-028>030.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 5 AM EST THURSDAY
FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LHZ349.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LHZ345>348.
LM...GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LMZ341-342.
GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1208 AM EST WED FEB 29 2012
.UPDATE...
ISSUED AT 1035 PM EST TUE FEB 28 2012
HAVE UPGRADED SOME COUNTIES IN NORTHERN LOWER MICHIGAN TO A
WARNING.
LOW PRESSURE NOW ADVANCING THROUGH EASTERN IOWA AHEAD OF A VERY
VIGOROUS UPPER LEVEL SHORT WAVE EJECTING NORTHEASTWARD FROM THE
CENTRAL PLAINS. VERY STRONG PULSE OF WARM ADVECTION FORCING/MOISTURE
FEED STARTING TO TAP THE GULF LEADING TO TO A LARGE EXPANDING
SHIELD OF PRECIP FROM ILLINOIS UP ACROSS WISCONSIN/MINNESOTA AND
THE DAKOTAS. STRONG CONVECTION BREAKING OUT IN THE CENTRAL PLAINS.
PRETTY MUCH YOUR TYPICAL STRONG SPRING STORM.
ACROSS THE REGION...A PRETTY HEFTY BATCH OF SNOWFALL HAS ALREADY
BLOSSOMED OVER SRN/ERN WISCONSIN THIS EVENING AND ABOUT TO WORK
INTO THE SW PART OF THIS CWA. BUT THE STRONGEST FORCING IS YET TO
ARRIVE...
OVERNIGHT...LOW PRESSURE SYSTEM WILL OCCLUDE OVER THE
IOWA/MINNESOTA REGION OVER THE NEXT SEVERAL HOURS. AS THIS
OCCURS...VERY STRONG PULSE OF WARM ADVECTION FORCING AND
ASSOCIATED WING OF PRECIP WILL ADVANCE UP THROUGH LOWER MICHIGAN
OVERNIGHT AND UP INTO EASTERN UPPER MICHIGAN WEDNESDAY
MORNING...FOLLOWED BY A SHARP DRY PUNCH OF AIR WORKING THROUGH THE
CWA DURING THE AFTERNOON. PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST THINKING.
INITIALLY...WAS SKEPTICAL OF NAM/GFS QPF AMOUNTS APPROACHING ONE
INCH BY WEDNESDAY EVENING WITH THIS STORM...ESPECIALLY GIVEN THAT
BULK OF PRECIP WILL ONLY LAST AROUND 6 HOURS BEFORE TAPERING OFF
SHARPLY TO DRIZZLE/FREEZING DRIZZLE WITHIN THE DRY SLOT DURING THE
AFTERNOON HOURS. HOWEVER...MODEL N-S CROSS SECTIONS ACROSS LOWER
MICHIGAN HAVE CHANGED MY MIND. VERY IMPRESSIVE F-GEN DEVELOPS
ACROSS THE REGION WEDNESDAY MORNING WITHIN THE SHARPLY CYCLONIC
FLOW AND VERY STRONG WIND CORE THAT WORKS UP THROUGH THE REGION.
RESULTING OMEGA BULLSEYE IS IMPRESSIVE...MAXIMIZING IN THE DGZ
RIGHT UP ACROSS NRN LOWER MICHIGAN FOR A TIME WEDNESDAY MORNING.
TERRAIN AND A STRONG SE LOW LEVEL FLOW WILL LIKELY HELP THE CAUSE
OVER NE AND NORTH CENTRAL LOWER MICHIGAN AS WELL.
GIVEN THAT...AND A SLIGHTLY SLOWER TREND IN THE 00Z GUIDANCE SUGGESTING
MORE PRECIP OVER NRN LOWER MICHIGAN...HAVE EXPANDED WARNING DOWN
TWO TIER OF COUNTIES IN NRN LOWER MICHIGAN. HAVE TENTATIVELY LEFT
OUT CHARLEVOIX/ANTRIM COUNTIES AS DOWNSLOPING SE FLOW MAY KEEP PRECIP
IN CHECK...WILL SEE. STILL NOT CONVINCED WE SEE AN INCH OF LIQUID
WITH THIS SYSTEM. BUT EVEN IF WE GET CLOSE...ACCUMULATIONS IN THE
4 TO 7 INCH RANGE CERTAINLY VERY POSSIBLE OVER PORTIONS OF NE
LOWER MICHIGAN.
PRECIP TYPE ISSUES REMAIN WITH THIS SYSTEM...AS ABOVE FREEZING
WARM NOSE SURGES UP INTO NRN LOWER MICHIGAN ON WEDNESDAY.
BUT...TIMING IS EVERYTHING...AND BULK OF PRECIP ACROSS THE CWA
WILL BE LARGELY OVER BEFORE THE WARM NOSE ARRIVES. SO AT THIS
POINT...AM NOT TOO CONCERNED ABOUT SIGNIFICANT ICING OR PRECIP
CHANGING TO RAIN...AT LEAST DURING THE HEAVIEST PART OF THE EVENT.
UPDATE ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1208 AM EST WED FEB 28 2012
LOW PRESSURE OVER THE MIDWEST WILL ADVANCE INTO THE WESTERN GREAT
LAKES ON WEDNESDAY...AND THEN SLOWLY MOVE THROUGH LOWER MICHIGAN
WEDNESDAY NIGHT. AHEAD OF THE LOW...FIRST ROUND OF PRECIP STARTING
TO WORK INTO THE NRN LOWER MICHIGAN AND WILL OVERSPREAD THE
TERMINAL SITES...SOUTH THROUGH NORTH...THROUGHOUT THE OVERNIGHT
HOURS. AS THIS OCCURS...CONDITIONS WILL DETERIORATE TO IFR BY
MORNING (SEE TAFS FOR TIMING DETAILS).
ROUND OF FAIRLY HEAVY PRECIP (MAINLY SNOW) WILL IMPACT NRN LOWER
MICHIGAN WEDNESDAY MORNING BEFORE TAPERING OFF TO LIGHT SNOW/DRIZZLE
OR FREEZING DRIZZLE...SOUTH-NORTH DURING THE AFTERNOON...AS MID
LEVEL DRY SLOT ADVANCES UP THROUGH THE REGION. LOW CIGS/VSBYS WILL
REMAIN HOWEVER.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS THROUGH MUCH OF
THE DAY.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ019>021-
025>027-031>036-041-042.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ016>018-022>024-028>030.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR LHZ349.
GALE WARNING UNTIL 11 PM EST WEDNESDAY FOR LHZ345>348.
LM...GALE WARNING UNTIL 11 PM EST WEDNESDAY FOR LMZ341-342.
GALE WARNING UNTIL 5 PM EST WEDNESDAY FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...BA
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1100 PM CST TUE FEB 28 2012
.DISCUSSION...ISSUED 300 PM CST
WHAT A DIFFERENCE ABOUT 125 MILES MAKES... WHICH IS ROUGHLY THE
DIFFERENCE IN WHERE THIS SYSTEM LOOKS TO BE TRACKING VS HOW IT
APPEARED TWO DAYS AGO. OVERALL... THIS MEANS THE FORECAST IS
PRETTY SIMILAR TO WHAT HAS BEEN EXPECTED... EXCEPT EVERYTHING HAS
BEEN SHIFTED BY ABOUT THAT DISTANCE NORTHWARD. THERE WILL BE SOME
ADDITIONAL CHANGES FORTHCOMING IN TERMS OF THE HEADLINES AND
SNOWFALL EXPECTATIONS... AS WELL AS THE NORTHWARD EXTENT OF MIXED
PRECIPITATION. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW OUR SYSTEM FINALLY BEGINNING TO EMERGE FROM THE
SOUTHERN ROCKIES... WITH THE SURFACE LOW LOCATED NEAR THE
INTERSECTION OF COLORADO... NEBRASKA... AND KANSAS. THE GUIDANCE
IS... FINALLY... IN EXCELLENT AGREEMENT ON THE TIMING AND MOVEMENT
OF THIS SYSTEM... TAKING THE SURFACE LOW NORTHEAST INTO SOUTHERN
MINNESOTA BY 12Z WEDNESDAY... THEN VERY NEAR THE TWIN CITIES BY
18Z... BEFORE MOVING OFF TO THE GREAT LAKES WEDNESDAY NIGHT. SOME
DIFFERENCES DO REMAIN IN THE GUIDANCE IN TERMS OF EXACTLY HOW WARM
THE ELEVATED WARM LAYER WILL GET... AS WELL AS THE NEAR SURFACE
TEMPERATURES AND NORTHWARD EXTENT OF THE WARMER TEMPERATURES.
OVERALL... IT NOW LOOKS LIKE WE SHOULD GET SOME DEGREE OF MIXED
PRECIPITATION OVER ALL BUT PERHAPS THE FAR NORTHERN PART OF THE
AREA FOR A TIME TONIGHT. THE SOUTHERN CWFA HAS ALREADY
TRANSITIONED TO SLEET OR RAIN... AND THIS WILL CONTINUE TO PUSH
NORTH THROUGH THE EVENING. BASED THE FORECAST DETAILS ON A BLEND
OF GFS... NAM... AND SREF GUIDANCE... BUT WITH A BIT OF WEIGHT ON
THE RUC DURING THE FIRST 12 HOURS. ALSO LIKE THE GENERAL LOOK OF
THE HRRR PRECIPITATION/REFLECTIVITY FIELDS THROUGH THIS EVENING...
SO TOOK THAT INTO ACCOUNT.
AS MENTIONED... EXPECT TO SEE THE MIXED PRECIPITATION PUSH NORTH
THROUGH THIS EVENING AS THE STRONG LOW LEVEL JET PERSIST AHEAD OF
THE SURFACE LOW. SUFFICIENTLY WARM TEMPERATURES AROUND 850-825MB
LOOK TO GET AS FAR NORTH AS KAXN... BRINGING SOME CHANCE OF AT
LEAST ICE PELLETS INTO THE FAR NORTHERN PART OF THE FORECAST AREA.
A BRIEF WINDOW OF FREEZING RAIN STILL SEEMS POSSIBLE DURING THE
TRANSITION FROM SLEET TO RAIN WHICH WILL OCCUR OVER THE CENTRAL
AND SOUTHERN PART OF THE CWFA... ALTHOUGH OBSERVATIONS AND
FORECAST PROFILES SUGGEST THAT ANY FZRA SHOULD BE SHORT-LIVED WITH
THINGS PRIMARILY GOING FROM SLEET TO RAIN OVER NEARLY THE SOUTHERN
HALF OF THE AREA BY EARLY THIS EVENING. AS THE SYSTEM OCCLUDES
LATER TONIGHT AND WEDNESDAY MORNING AND BEGINS DRIFTING EAST WE
SHOULD SEE THINGS COOL DOWN ONCE AGAIN... WITH THE WARM TONGUE
ERODING FROM 09Z-15Z... CHANGING THE PCPN ASSOCIATED THE UPPER
TROUGH BACK TO SNOW FOR THE DAY ON WEDNESDAY. PRIOR TO THEN... IT
STILL APPEARS THAT WE WILL HAVE HEAVY PCPN TONIGHT... FALLING AS
SNOW AND SLEET OVER THE NORTH... SLEET AND RAIN OVER THE
CENTRAL... AND RAIN OVER THE SOUTH. HOWEVER... THE SOUTHERN PART
OF THE AREA SHOULD ALSO SEE THE DRY SLOT WORK IN... WHICH WILL END
HEAVIER PCPN IN THAT AREA TONIGHT. THERE IS SOME POSSIBILITY FOR
SOME CONVECTION TO DEVELOP IN THE DRY WEDGE... MAINLY TO OUR
SOUTH... BUT SOME ISOLATED THUNDER COULD GET UP INTO THE SOUTHERN
PART OF THE CWFA THIS EVENING INTO THE OVERNIGHT HOURS. IN THE
NORTH... WHERE THE PERSISTENT MODERATE TO HEAVY PCPN IS EXPECTED
TO OCCUR... SIGNIFICANT SNOWFALL ACCUMULATIONS STILL APPEAR
LIKELY... ALTHOUGH THEY MAY BE TEMPERED TO SOME DEGREE BY MIXING
WITH SLEET. STRONG MID-LEVEL FRONTOGENESIS... AND COUPLING WITH
THE UPPER JET CIRCULATION... STILL APPEAR TO BE IN PLACE FOR A
TIME TONIGHT... ALONG WITH NEGATIVE EPV NEAR AND ABOVE THAT LAYER
OF FORCING. OVER THE SOUTHERN PART OF THE AREA... THAT INSTABILITY
IS UPRIGHT GIVEN NEGATIVE DIFFERENTIAL THETA-E WHICH WILL BE IN
PLACE... BUT AS YOU GO NORTH THINGS SUGGEST IT WOULD BE MORE
SYMMETRIC IN NATURE. THAT WOULD SUGGEST MORE OF A CELLULAR PCPN
LOOK ON THE SOUTH END OF THINGS AS THEY PUSH NORTH LATER
TONIGHT... WITH MORE IN THE WAY OF BANDING FARTHER NORTH.
PCPN WILL LINGER THROUGH MUCH OF THE DAY ON WEDNESDAY AS THE UPPER
TROUGH SLOWLY PUSHES ACROSS THE AREA AND ABUNDANT DEEP LAYER
MOISTURE PERSISTS. SOME MIXED PCPN MAY STILL BE POSSIBLE IN THE
MORNING OVER THE SOUTHEAST PORTION OF THE AREA... BUT BY LATE
MORNING ANY REMAINING PCPN SHOULD BE IN THE FORM OF SNOW... WITH
SOME ADDITIONAL ACCUMULATIONS STILL EXPECTED... PARTICULARLY OVER
THE NORTH CENTRAL AND NORTHEAST CWFA. VERY WEAK RIDGING LOOKS TO
WORK INTO THE AREA WEDNESDAY NIGHT... BRINGING AN END THE PCPN...
BUT A WEAK NORTHERN STREAM SHORTWAVE MAY BRING A CHANCE OF SNOW
BACK INTO THE NORTHERN CWFA ON THURSDAY. THE NEXT FEATURE OF ANY
CONCERN STILL LOOKS LIKE IT WILL BE MOVING NEAR THE AREA ON
FRIDAY... BUT THE LATEST GUIDANCE CONTINUES THE IDEA OF KEEPING
THAT SYSTEM OFF TO OUR SOUTHEAST. WITH THE AFOREMENTIONED NORTHERN
STREAM UPPER TROUGH STILL IN THE VICINITY THROUGH FRIDAY... AND
THE SOUTHERN WAVE PASSING BY TO OUR SOUTHEAST... DID CARRY SOME
LOW POPS OVER MUCH OF THE AREA ON FRIDAY... BUT AT THIS POINT IT
DOES NOT APPEAR IT WILL BE MUCH OF AN ISSUE FOR OUR AREA. THE
WEEKEND INTO EARLY NEXT WEEK LOOK TO BE MAINLY DRY... ALTHOUGH
THERE COULD BE SOME FLURRIES AROUND OVER THE WEEKEND WITH CYCLONIC
FLOW AND FAIRLY STEEP BOUNDARY LAYER LAPSE RATES IN PLACE. DIDN/T
INCLUDE MUCH IN THE WAY OF PCPN MENTION AT THIS POINT... BUT
WOULDN/T BE SURPRISED TO EVENTUALLY NEED TO INCLUDE SOME SNOW
SHOWERS AND/OR FLURRIES FOR SATURDAY INTO SUNDAY. THE START OF
NEXT WEEK SHOULD SEE A SIGNIFICANT WARM UP ACROSS THE AREA AS
HEIGHTS BUILD... AND 1000-500MB THICKNESS VALUES CLIMB WELL ABOVE
555DM. INCLUDED HIGHS OF NEAR 50 DEGREES BY TUESDAY... WHICH
CERTAINLY DOESN/T LOOK UNREASONABLE AT THIS POINT SHOULD THINGS
WARM AS SUGGESTED.
&&
.AVIATION.../06Z TAF ISSUANCE/
00Z RUNS OF GFS/NAM NOW TAKE SFC LOW SLIGHTLY FARTHER SOUTH NEXT 24
HOURS...TRACKING JUST SOUTH OF MSP TO S OF EAU. FIRST WAVE OF PCPN
NOW COVERS ABOUT NE 1/2 OF CWA...WITH SOME SNOW TOTALS IN THE 2-4
INCH RANGE SO FAR ACROSS PARTS OF CNTL MN INTO WC WI. SFC TEMPS HAVE
BEEN STUBBORN TO RISE...HOLDING 31 TO 34 RANGE AT SITES WITH MIXED
PCPN MSP/RWF/EAU. PCPN HAS REMAINED ALL SNOW AT AXN/STC.
NEXT WAVE OF PCPN WITH SOME THUNDER IS ADVANCING INTO SW MN AHEAD OF
STRENGTHENING UPPER LOW. WILL HAVE A PERIOD OF THUNDER FOR RWF TIL
09Z. WV IMAGERY SHOWING COOLING CLOUD TOPS COOLING ACROSS SODAK/E
NEB/IA/SW MN AHEAD OF UPPER LOW. NAM IS A BIT MORE AGGRESSIVE ON
COOLING LOWER ATMOS COLUMN OVERNIGHT THAN GFS. METARS TEND TO
SUPPORT COOLER NAM WITH PCPN TRENDING TOWARD MORE SNOW.
STRONG ISENTROPIC LIFT AND PERSISTENT UVV ACROSS CENTRAL MN INTO WC
OVERNIGHT INTO WED MRNG SHUD YIELD PERIODS OF +SN AFFECING MAINLY
STC/AXN. SPED UP THE TRANSISTION TO SNOW A BIT ACROSS REMAINING
TAFS.
MSP...FIRST WAVE OF MIXED PCPN PULLING NE OF MSP WITH NEXT WAVE
RAPIDLY MOVING NE ACROSS SW MN...ARRIVING IN MSP BY 07Z. SFC TEMPS
WILL REMAIN JUST ABOVE FREEZING. METARS HAVE BEEN REPORTING -SN AS
CLOSE AS MIC/GYL. WITH LIFT FROM APPROACHING UPPER LOW SHOULD
CHANGE TO A MIX OF SNPL AROUND 09Z AND ALL SNOW BY 12Z. KEPT THUNDER
CHANCE S OF MSP..BUT COULD BE CLOSE BETWEEN 08Z AND 11Z. EXPECT SNOW
TOTALS AT MSP INTO MID DAY WEDNESDAY AROUND 3 INCHES. SFC WINDS WILL
BE A BIT STRONGER THAN PREVIOUS TAF WITH SFC LOW TRACKING S OF MSP.
.WED NIGHT...IFR/MVFR CIGS.
.THU/FRI. MVFR CIGS/VSBYS IN -SN. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR BROWN-
CARVER-DAKOTA-GOODHUE-HENNEPIN-LE SUEUR-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-WASHINGTON-YELLOW
MEDICINE.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR ANOKA-BENTON-
CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MEEKER-MORRISON-
POPE-SHERBURNE-STEARNS-STEVENS-SWIFT-TODD-WRIGHT.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHISAGO-ISANTI-
KANABEC-MILLE LACS.
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR DUNN-EAU
CLAIRE-PEPIN-PIERCE-ST. CROIX.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHIPPEWA.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR BARRON-POLK-
RUSK.
&&
$$
CLF/BAP
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
220 AM CST WED FEB 29 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
/ISSUED 0215 AM CST WED FEB 29 2012/
A DANGEROUS LINE OF STORMS CONTINUES TO RACE ACROSS SOUTH CENTRAL
MISSOURI AND WILL CONTINUE ACROSS SOUTHERN MISSOURI THROUGH 5 AM.
NUMEROUS REPORTS OF WIND GUSTS IN EXCESS OF 70 MPH...HAIL TO THE
SIZE OF GOLF BALLS AND TORNADOES HAVE BEEN RECEIVED. THE THREAT
FOR SIGNIFICANT SEVERE WEATHER WILL CONTINUE THROUGH THE EASTERN
PORTION OF THE OUTLOOK AREA THROUGH 5 AM.
DIVING INTO VARIOUS MESOSCALE PARAMETERS...SIGNIFICANT O-1KM AND
0-3KM STORM RELATIVE HELICITY VALUES OF OVER 800 M2/S2 ARE
AVAILABLE ALONG AND AHEAD OF THE LINE OF CONVECTION. RUC BUFKIT
SOUNDINGS AHEAD OF THE LINE CONTINUE TO INDICATE STRONG 925MB
WINDS OF NEAR 50 KTS AND 850MB WINDS OF 60 TO 65KTS...WITH THIS
CONTINUING TO SUPPORT OUR STRONG SRH VALUES. SPC MESOANALYSIS PAGE
CONTINUES TO SHOW MLCAPE VALUES OVER 1000 J/KG ACROSS THE REGION.
RUC FORECASTS OF 0-1KM COMPUTED CAPE SHOW VALUES BETWEEN 300 AND
500 J/KG JUST AHEAD OF THE CONVECTIVE LINE...WITH NEAR 1000 J/KG
NOSING INTO THE EASTERN OZARKS. THESE PARAMETERS CONTINUE TO
SUPPORT OUR ELEVATED TORNADO RISK WITH BOWING SEGMENTS MOVING EAST
NORTHEAST ACROSS SOUTH CENTRAL MISSOURI.
WINDS IN EXCESS OF 70 MPH...TORNADOES AND LARGE HAIL WILL REMAIN
AN ELEVATED TO SIGNIFICANT RISK FOR THE REST OF TONIGHT WITH THIS
LINE OF STORMS. THIS IS A DANGEROUS SITUATION.
KURTZ
&&
.AVIATION...
FOR THE 06Z TAF PACKAGE...PRIMARY CONCERN WILL BE THE LINE OF
THUNDERSTORMS MOVING ACROSS THE REGION...EXPECT GUSTS AT BBG TO
PEAK NEAR 50KT OUT OF THE WEST. ONCE THIS LINE CLEARS TO THE
EAST...VFR CONDITIONS ARE EXPECTED...THOUGH GUSTY WEST WINDS WILL
CONTINUE THROUGH THE DAY.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1258 AM CST WED FEB 29 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
/ISSUED 1258 AM CST WED FEB 29 2012/
DANGEROUS LINE OF STORMS WILL RACE THROUGH THE AREA THROUGH 5 AM.
NUMEROUS REPORTS OF WIND GUSTS IN EXCESS OF 70 MPH...HAIL TO THE
SIZE OF GOLF BALLS AND TORNADOES HAVE BEEN RECEIVED. THE THREAT
FOR SIGNIFICANT SEVERE WILL CONTINUE THROUGH THE ENTIRE OUTLOOK
AREA WITH THIS LINE OF THUNDERSTORMS.
REFERENCING SPC/S MESOANALYST PAGE...MLCAPE IS NEAR 1000 J/KG WITH
0-1KM AND 0-3KM STORM RELATIVE HELICITY NEAR 750 M2/S2. GIVEN
925MB WINDS OF 50KT AND 850MB WINDS OF 70KT (AS MEASURED BY THE
04Z SPECIAL KSGF SOUNDING)...THE SRH VALUES PRODUCED ARE LIKELY
REPRESENTATIVE. RUC REPRESENTATION OF LOW LEVEL CAPE ESTIMATES
VALUES ARE 100 J/KG. THIS COMBINED WITH THE HIGH SRH VALUES IN THE
LOW LEVELS WILL MAINTAIN AN ELEVATED TORNADO RISK WITH THE BOW
ECHO SIGNATURE THAT IS MOVING EAST NORTHEAST THROUGH CENTRAL
MISSOURI AS WELL AS ANY OTHER LINE SEGMENTS THAT BECOME FAVORABLY
ORIENTED WITH THE WEST/SOUTHWEST 0-3KM SHEAR VECTORS.
WINDS IN EXCESS OF 70 MPH...TORNADOES AND LARGE HAIL WILL REMAIN
AN ELEVATED TO SIGNIFICANT RISK FOR THE REST OF TONIGHT WITH THIS
LINE OF STORMS. THIS IS A DANGEROUS SITUATION.
GAGAN
&&
.AVIATION...
FOR THE 06Z TAF PACKAGE...PRIMARY CONCERN WILL BE THE LINE OF
THUNDERSTORMS MOVING ACROSS THE REGION...EXPECT GUSTS AT BBG TO
PEAK NEAR 50KT OUT OF THE WEST. ONCE THIS LINE CLEARS TO THE
EAST...VFR CONDITIONS ARE EXPECTED...THOUGH GUSTY WEST WINDS WILL
CONTINUE THROUGH THE DAY.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
347 AM EST WED FEB 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND NEW YORK STATE WILL
SLIDE TO THE EAST AS LOW PRESSURE OVER THE MIDWEST MOVES EASTWARD.
THERE WILL BE A MIX OF RAIN...SLEET AND SNOW ACROSS PARTS OF WESTERN
AND CENTRAL NEW YORK ON WEDNESDAY MORNING...THEN MAINLY RAIN AND
SNOW FOR THE AFTERNOON. RAIN WILL CHANGE BACK TO SNOW AND TAPER OFF
WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE OVERNIGHT PERIOD WILL BE CLOUDY AND MAINLY DRY. WHILE
COMPOSITE RADAR APPEARS FAIRLY OMINOUS...THE 00Z BUFFALO SOUNDING
SHOWS QUITE DRY AIR BELOW 700 MB. THUS THE MAJORITY OF THE
COMPOSITE RADAR IS ACTUALLY VIRGA. THIS SAID...REFLECTIVITY OF 25
DBZ OR SO SUGGESTS SOME FLURRIES ARE LIKELY REACHING THE GROUND
IN SOME SPOTS. THIS BAND OF MID-UPPER LEVEL WARM AIR ADVECTION
WILL CONTINUE TO LIFT OFF TO THE NORTH...PERHAPS BRINGING A FLURRY
TO BUFFALO AND FAR WESTERN NEW YORK. HOWEVER...THIS SHOULD LIFT TO
THE NORTH SHORTLY AFTER MIDNIGHT...WHILE THE MAIN AREA OF
PRECIPITATION SHOULD NOT ENTER THE REGION UNTIL DAYBREAK. THE 18Z
GFS/12Z RGEM/00Z HRRR ALL BRING IN STEADY PRECIPITATION INTO FAR
WESTERN PORTIONS OF NEW YORK JUST SHY OF 12Z (700 AM). WITH CLOUDS
IN PLACE ACROSS MOST OF THE REGION... TEMPERATURES SHOULD DROP
VERY LITTLE OVERNIGHT.
A WARM FRONT BETWEEN THE DEPARTING HIGH AND APPROACHING LOW WILL
BRING ABOUT A MIX OF WINTRY PRECIP TO PARTS OF WESTERN AND CENTRAL
NY. THIS WILL BRING A BAND OF WARM AIR ADVECTION IN THE LOWER TO
MID LEVELS...WHICH WILL LIFT FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION ON WEDNESDAY. THERE SHOULD BE A RATHER QUICK CHANGEOVER TO
RAIN IN FAR SOUTHERN SECTIONS...WHERE WINDS SHIFTING TO THE
SOUTHEAST WILL BRING IN WARM AIR ALOFT. FURTHER TO THE NORTH AND
EAST WILL BE FURTHER FROM THE SURFACE LOW AND CLOSER TO COLD HIGH
PRESSURE ANCHORED IN QUEBEC. THIS WILL ALLOW SNOW TO LAST
LONGER INTO WEDNESDAY...WITH LOCATIONS EAST OF LAKE ONTARIO LIKELY
TO STAY SNOW THROUGH SUNSET.
NO CHANGES TO HEADLINES WERE MADE FOR THE EVENING UPDATE. HAVE
SOME CONCERN THAT TEMPERATURES WEDNESDAY MORNING WILL BE SLOW TO
RISE...GIVEN THE INVERSION FORECAST TO DEVELOP BENEATH THE MODEST
SW FLOW ALOFT. THUS DID BUMP DOWN TEMPERATURES A FEW DEGREES ON
WEDNESDAY MORNING. ALSO NUDGED UP SNOW ACCUMULATIONS EAST OF
ROCHESTER. THE 18Z NAM CONTINUES TO BE COLDER THAN THE 18Z GFS AND
MOST OF THE 12Z MODELS...WITH THE SREF TENDING TO SUPPORT THE
WARMER MODEL CAMP AS WELL. A BLEND PROVIDES SIMILAR CHANGEOVER
TIMES TO GOING FORECAST...BUT PERHAPS A TAD MORE QPF BASED ON
LATEST CONSENSUS. EXPECT BETWEEN .25 AND .50 FROM THE BROAD BAND
OF WARM AIR ADVECTION. THIS SHOULD BRING LIGHT ACCUMULATIONS...GENERALLY
2 INCHES OR LESS...WEST OF ROCHESTER...WITH POTENTIAL FOR 2 TO 4
INCHES EAST OF ROCHESTER TO OSWEGO COUNTY THROUGH WEDNESDAY
EVENING.
THE GREATEST POTENTIAL FOR ANY ICE CONTINUES TO BE ACROSS THE
SOUTHERN TIER. WARM AIR ALOFT WILL CROSS QUITE EARLY WEDNESDAY
MORNING...HOWEVER BELOW FREEZING SURFACE TEMPERATURES WILL LIKELY
LINGER WELL INTO THE MORNING. WITH DEW POINTS IN THE UPPER TEENS
AND LOWER 20S...EXPECT SURFACE TEMPERATURES TO DROP EARLY
WEDNESDAY MORNING DUE TO EVAPORATIONAL COOLING. THE ADVISORY
APPEARS TO BE WELL PLACED FOR THIS...WITH A LIGHT GLAZE OF A TENTH
OF AN INCH OR SO OF ICE LIKELY IN THE ADVISORY AREA. IF SURFACE
TEMPERATURES DO LINGER BELOW FREEZING LONGER...IT IS POSSIBLE
ICING TO A QUARTER INCH COULD OCCUR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
THE WEAKENING/FILLING SURFACE WAVE WILL BE IN THE PROCESS OF
CROSSING THE REGION AT THE START OF THE PERIOD. THIS SYSTEM WILL
CONTINUE THE WIDESPREAD PRECIPITATION. COLDER AIR WILL ARRIVE BEHIND
THE LOW AS THE ASSOCIATED UPPER LOW CROSSES THE REGION ENHANCING
DYNAMIC COOLING. THIS PROCESS WILL ALLOW A CHANGE OVER TO A
RAIN/SNOW MIX WITH NEARLY ALL SNOW OVER HIGHER ELEVATIONS OF THE
SOUTHERN TIER AND ACROSS THE NORTH COUNTY. LITTLE ACCUMULATION
EXPECTED ACROSS THE SOUTHERN TIER...BUT COULD SEE ADDITIONAL
SNOWFALL AMOUNTS OF 2 INCHES ACROSS THE NORTH COUNTRY...IN AREA OF
DEEPER MOISTURE AND CLOSER TO THE MID LEVEL CIRCULATION.
THE PRECIPITATION LOOKS TO END THURSDAY NIGHT WITH A DRY DAY
EXPECTED FRIDAY...AS RIDGING ALOFT AND DRYING DEVELOP AHEAD OF NEXT
UPPER TROUGH DROPPING THROUGH THE ROCKIES. STRONG LOW LEVEL JET WILL
PUSH 850 MB TEMPERATURES TO NEAR +8C WHICH WILL SEND TEMPERATURES
WELL ABOVE NORMAL...ESPECIALLY IF ANY SUNSHINE CAN DEVELOP.
ALTHOUGH UPPER 30S COULD LINGER ACROSS THE NORTH COUNTRY...MOST
AREAS WILL HAVE WELL ABOVE NORMAL TEMPERATURES IN THE UPPER 40S TO
LOWER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MAIN FOCUS FOR THIS PERIOD WILL BE A POTENTIALLY STRONG STORM
SYSTEM PROGGED TO IMPACT THE REGION THIS WEEKEND. MODEL AGREEMENT IS
FAIRLY DECENT ON THE TIMING OF THE CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS EARLY FRIDAY. THIS LOW MOVES UP INTO THE GREAT LAKES
FRIDAY NIGHT WHILE DEEPENING RAPIDLY COURTESY OF A STRONG UPPER
TROUGH IMMEDIATELY UPSTREAM AND A POWERFUL UPPER JET MOVING ACROSS
THE OHIO VALLEY INTO THE NORTHEASTERN U.S.. A VERY STRONG LOW LEVEL
JET WILL ADVECT AN EXTREMELY WARM AIRMASS INTO THE REGION AHEAD OF THE
APPROACHING LOW WITH 850MB TEMPS POTENTIALLY REACHING
+10C...YIELDING HIGHS THAT COULD EASILY REACH INTO THE 50S ON
FRIDAY. FOR FRIDAY NIGHT...INCREASING INSTABILITY AHEAD OF THE
APPROACHING FRONT GIVEN THE EXTREME WARM ADVECTION AND SHOWALTER
INDICES THAT DROP BELOW ZERO AND THE STRONG DYNAMICS ALOFT...HAVE
OPTED TO INCLUDE A MENTION OF THUNDERSTORMS. IN ADDITION...THE
POTENTIAL STRENGTH OF THE SOUTHERLY LOW LEVEL JET WILL CREATE THE
POTENTIAL FOR VERY STRONG WINDS ACROSS HIGH TERRAIN AND DOWNSLOPING
AREAS ALONG LAKE ERIE.
THE LOW PASSES TO OUR NORTHWEST INTO CENTRAL QUEBEC SATURDAY WHILE
SWEEPING A COLD FRONT ACROSS THE REGION. GIVEN THE VERY STRONG LOW
LEVEL JET AHEAD OF THE FRONT AND SUBSIDENCE BEHIND THE FRONT...SEE
THE POTENTIAL FOR ADVISORY TO LOW END WARNING LEVEL WINDS BEHIND THE
FRONT ON SATURDAY. AS ALWAYS THOUGH...IT IS BEST TO BE CAUTIOUS THIS
FAR OUT AS THERE ARE MANY MORE MODEL RUNS TO FINE TUNE THE DETAILS
OF THIS DEVELOPING STORM SYSTEM.
FOR SUNDAY AND MONDAY...THE LONGWAVE UPPER LEVEL TROUGH TRANSITS THE
REGION WITH COLD AIR SWEEPING ACROSS THE REGION USHERING IN A RETURN
TO WINTER. THE COLD ADVECTION WILL BRING A POTENTIAL FOR LAKES SNOWS
THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
EXPECT ONLY HIGH CLOUDS...WITH VFR CONDITIONS TO LAST THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE ON WEDNESDAY
MORNING. THIS WILL START AS SNOW OR MIXED
PRECIPITATION...EVENTUALLY TRENDING TO ALL RAIN. MIXED PRECIPITATION
AND SNOW WILL LAST LONGER TO THE NE...LASTING LONGER AT ART/ROC
THAN AT BUF/IAG/JHW. INCREASING MOISTURE WILL LIKELY LOWER ALL
SITES TO IFR OR LOWER AT TIMES WEDNESDAY. STEADY PRECIPITATION
SHOULD TAPER TO SHOWERS LATE AFTERNOON INTO WEDNESDAY EVENING.
OUTLOOK...
WEDNESDAY NIGHT...MVFR IN RAIN...POSSIBLY SNOW NEAR ART.
THURSDAY...MVFR RAIN AND SNOW SHOWERS LIKELY.
FRIDAY...GENERALLY VFR.
SATURDAY...MVFR IN CHC OF SHOWERS.
SUNDAY...VFR/MVFR SCTD SNOW SHOWERS.
&&
.MARINE...
EASTERLY WINDS PICK UP ON THE LAKES LATER TONIGHT INTO WEDNESDAY
MORNING AS A WARM FRONT LIFTS NORTH ACROSS OHIO. WINDS AND WAVES
WILL INCREASE OVER WESTERN LAKE ONTARIO AND WILL WARRANT A SMALL
CRAFT ADVISORY FROM THE NIAGARA RIVER TO SODUS BAY. WINDS WILL
VEER TO THE SOUTH AND DIMINISH DURING THE AFTERNOON ON LAKE
ERIE...WHILE A MORE PERSISTENT EAST SOUTHEAST FLOW REMAINS IN
PLACE ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 4 PM EST
THURSDAY FOR NYZ006>008.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ012-
019>021-085.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ013-014.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 4 AM EST
THURSDAY FOR LOZ042-043.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...TMA
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1153 PM EST TUE FEB 28 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND NEW YORK STATE WILL
SLIDE TO THE EAST AS LOW PRESSURE OVER THE MIDWEST MOVES EASTWARD.
THERE WILL BE A MIX OF RAIN...SLEET AND SNOW ACROSS PARTS OF WESTERN
AND CENTRAL NEW YORK ON WEDNESDAY MORNING...THEN MAINLY RAIN AND
SNOW FOR THE AFTERNOON. RAIN WILL CHANGE BACK TO SNOW AND TAPER OFF
WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
THE OVERNIGHT PERIOD WILL BE CLOUDY AND MAINLY DRY. WHILE
COMPOSITE RADAR APPEARS FAIRLY OMINOUS...THE 00Z BUFFALO SOUNDING
SHOWS QUITE DRY AIR BELOW 700 MB. THUS THE MAJORITY OF THE
COMPOSITE RADAR IS ACTUALLY VIRGA. THIS SAID...REFLECTIVITY OF 25
DBZ OR SO SUGGESTS SOME FLURRIES ARE LIKELY REACHING THE GROUND
IN SOME SPOTS. THIS BAND OF MID-UPPER LEVEL WARM AIR ADVECTION
WILL CONTINUE TO LIFT OFF TO THE NORTH...PERHAPS BRINGING A FLURRY
TO BUFFALO AND FAR WESTERN NEW YORK. HOWEVER...THIS SHOULD LIFT TO
THE NORTH SHORTLY AFTER MIDNIGHT...WHILE THE MAIN AREA OF
PRECIPITATION SHOULD NOT ENTER THE REGION UNTIL DAYBREAK. THE 18Z
GFS/12Z RGEM/00Z HRRR ALL BRING IN STEADY PRECIPITATION INTO FAR
WESTERN PORTIONS OF NEW YORK JUST SHY OF 12Z (700 AM). WITH CLOUDS
IN PLACE ACROSS MOST OF THE REGION... TEMPERATURES SHOULD DROP
VERY LITTLE OVERNIGHT.
A WARM FRONT BETWEEN THE DEPARTING HIGH AND APPROACHING LOW WILL
BRING ABOUT A MIX OF WINTRY PRECIP TO PARTS OF WESTERN AND CENTRAL
NY. THIS WILL BRING A BAND OF WARM AIR ADVECTION IN THE LOWER TO
MID LEVELS...WHICH WILL LIFT FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION ON WEDNESDAY. THERE SHOULD BE A RATHER QUICK CHANGEOVER TO
RAIN IN FAR SOUTHERN SECTIONS...WHERE WINDS SHIFTING TO THE
SOUTHEAST WILL BRING IN WARM AIR ALOFT. FURTHER TO THE NORTH AND
EAST WILL BE FURTHER FROM THE SURFACE LOW AND CLOSER TO COLD HIGH
PRESSURE ANCHORED IN QUEBEC. THIS WILL ALLOW SNOW TO LAST
LONGER INTO WEDNESDAY...WITH LOCATIONS EAST OF LAKE ONTARIO LIKELY
TO STAY SNOW THROUGH SUNSET.
NO CHANGES TO HEADLINES WERE MADE FOR THE EVENING UPDATE. HAVE
SOME CONCERN THAT TEMPERATURES WEDNESDAY MORNING WILL BE SLOW TO
RISE...GIVEN THE INVERSION FORECAST TO DEVELOP BENEATH THE MODEST
SW FLOW ALOFT. THUS DID BUMP DOWN TEMPERATURES A FEW DEGREES ON
WEDNESDAY MORNING. ALSO NUDGED UP SNOW ACCUMULATIONS EAST OF
ROCHESTER. THE 18Z NAM CONTINUES TO BE COLDER THAN THE 18Z GFS AND
MOST OF THE 12Z MODELS...WITH THE SREF TENDING TO SUPPORT THE
WARMER MODEL CAMP AS WELL. A BLEND PROVIDES SIMILAR CHANGEOVER
TIMES TO GOING FORECAST...BUT PERHAPS A TAD MORE QPF BASED ON
LATEST CONSENSUS. EXPECT BETWEEN .25 AND .50 FROM THE BROAD BAND
OF WARM AIR ADVECTION. THIS SHOULD BRING LIGHT ACCUMULATIONS...GENERALLY
2 INCHES OR LESS...WEST OF ROCHESTER...WITH POTENTIAL FOR 2 TO 4
INCHES EAST OF ROCHESTER TO OSWEGO COUNTY THROUGH WEDNESDAY
EVENING.
THE GREATEST POTENTIAL FOR ANY ICE CONTINUES TO BE ACROSS THE
SOUTHERN TIER. WARM AIR ALOFT WILL CROSS QUITE EARLY WEDNESDAY
MORNING...HOWEVER BELOW FREEZING SURFACE TEMPERATURES WILL LIKELY
LINGER WELL INTO THE MORNING. WITH DEW POINTS IN THE UPPER TEENS
AND LOWER 20S...EXPECT SURFACE TEMPERATURES TO DROP EARLY
WEDNESDAY MORNING DUE TO EVAPORATIONAL COOLING. THE ADVISORY
APPEARS TO BE WELL PLACED FOR THIS...WITH A LIGHT GLAZE OF A TENTH
OF AN INCH OR SO OF ICE LIKELY IN THE ADVISORY AREA. IF SURFACE
TEMPERATURES DO LINGER BELOW FREEZING LONGER...IT IS POSSIBLE
ICING TO A QUARTER INCH COULD OCCUR.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A TOUGH FORECASTING SCENARIO FOR WEDNESDAY NIGHT WITH A FAIR AMOUNT
OF UNCERTAINTY ACROSS THE NORTH COUNTRY. THE EVENING STARTS WITH A
WARM FRONT DRAPED ACROSS WESTERN NEW YORK. TEMPERATURES ACROSS MUCH
OF THE FORECAST AREA WILL LIKELY BE ABOVE FREEZING WITH TEMPS
STAYING IN THE MID TO UPPER 30S AND THE ASSOCIATED ISENTROPIC UPLIFT
WILL BRING WIDESPREAD RAINFALL WITH AROUND A TENTH OF AN INCH OF QPF
INT HE WARM SECTOR AS THE PRECIP TAPERS OFF AND THE FOCUS SHIFTS TO
THE NORTH COUNTRY THROUGH THE EVENING HOURS. HEAVIER PRECIP WILL BE
POSSIBLE ACROSS THE NORTH COUNTRY ON THE NOSE OF THE LOW LEVEL JET.
THE BIG QUESTION HERE IS PRECIP TYPE...AS SURFACE TEMPS HERE WILL BE
HOVERING RIGHT AROUND FREEZING. THE NAM KEEPS TEMPERATURES ALOFT MOSTLY
BELOW FREEZING ACROSS THE NORTH COUNTRY FOR THE BULK OF THE
PERIOD...RESULTING IN PRECIP TYPE STAYING MOSTLY SNOW BEFORE
SWITCHING OVER TO RAIN WHEREAS THE GFS BRINGS A MUCH WARMER NOSE
OVER THE AREA SOONER IN THE EVENING...WHICH WOULD RESULT IN A MUCH
GREATER RISK OF FREEZING RAIN AND SLEET. HAVE TRIED TO SHOOT IN THE
MIDDLE FOR NOW WITH A LITTLE BIT OF EVERYTHING AND WILL HOLD OFF ON
AN ADVISORY GIVEN THE UNCERTAINTY REGARDING THE LOCATION/STRENGTH OF
THE WARM NOSE AND THE FACT THAT WE ARE TALKING ABOUT THE THIRD
PERIOD.
COLDER AIR ADVECTS ACROSS THE REGION THURSDAY AS A WEAK COLD FRONT
CROSSES WESTERN NEW YORK. AS THE ASSOCIATED UPPER LOW MOVES OVER THE
AREA...EXPECT RAIN SHOWERS...MIXING WITH SNOW OVER THE HIGHER
ELEVATIONS TO LINGER. TEMPERATURES WILL STAY RELATIVELY MILD WITH
HIGHS IN THE UPPER 30S TO AROUND 40 AS 850MB TEMPS ONLY DROP TO
AROUND -6C. POPS DROP OFF THURSDAY NIGHT AS RIDGING BUILDS OVERHEAD
AND LOWS DROP TO AROUND FREEZING.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE MAIN FOCUS FOR THIS PERIOD WILL BE A POTENTIALLY STRONG STORM
SYSTEM PROGGED TO IMPACT THE REGION THIS WEEKEND. MODEL AGREEMENT IS
FAIRLY DECENT ON THE TIMING OF THE CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS EARLY FRIDAY. THIS LOW MOVES UP INTO THE GREAT LAKES
FRIDAY NIGHT WHILE DEEPENING RAPIDLY COURTESY OF A STRONG UPPER
TROUGH IMMEDIATELY UPSTREAM AND A POWERFUL UPPER JET MOVING ACROSS
THE OHIO VALLEY INTO THE NORTHEASTERN U.S.. A VERY STRONG LOW LEVEL
JET WILL ADVECT AN EXTREMELY WARM AIRMASS INTO THE REGION AHEAD OF THE
APPROACHING LOW WITH 850MB TEMPS POTENTIALLY REACHING
+10C...YIELDING HIGHS THAT COULD EASILY REACH INTO THE 50S ON
FRIDAY. FOR FRIDAY NIGHT...INCREASING INSTABILITY AHEAD OF THE
APPROACHING FRONT GIVEN THE EXTREME WARM ADVECTION AND SHOWALTER
INDICES THAT DROP BELOW ZERO AND THE STRONG DYNAMICS ALOFT...HAVE
OPTED TO INCLUDE A MENTION OF THUNDERSTORMS. IN ADDITION...THE
POTENTIAL STRENGTH OF THE SOUTHERLY LOW LEVEL JET WILL CREATE THE
POTENTIAL FOR VERY STRONG WINDS ACROSS HIGH TERRAIN AND DOWNSLOPING
AREAS ALONG LAKE ERIE.
THE LOW PASSES TO OUR NORTHWEST INTO CENTRAL QUEBEC SATURDAY WHILE
SWEEPING A COLD FRONT ACROSS THE REGION. GIVEN THE VERY STRONG LOW
LEVEL JET AHEAD OF THE FRONT AND SUBSIDENCE BEHIND THE FRONT...SEE
THE POTENTIAL FOR ADVISORY TO LOW END WARNING LEVEL WINDS BEHIND THE
FRONT ON SATURDAY. AS ALWAYS THOUGH...IT IS BEST TO BE CAUTIOUS THIS
FAR OUT AS THERE ARE MANY MORE MODEL RUNS TO FINE TUNE THE DETAILS
OF THIS DEVELOPING STORM SYSTEM.
FOR SUNDAY AND MONDAY...THE LONGWAVE UPPER LEVEL TROUGH TRANSITS THE
REGION WITH COLD AIR SWEEPING ACROSS THE REGION USHERING IN A RETURN
TO WINTER. THE COLD ADVECTION WILL BRING A POTENTIAL FOR LAKES SNOWS
THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
EXPECT ONLY HIGH CLOUDS...WITH VFR CONDITIONS TO LAST THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE ON WEDNESDAY
MORNING. THIS WILL START AS SNOW OR MIXED
PRECIPITATION...EVENTUALLY TRENDING TO ALL RAIN. MIXED PRECIPITATION
AND SNOW WILL LAST LONGER TO THE NE...LASTING LONGER AT ART/ROC
THAN AT BUF/IAG/JHW. INCREASING MOISTURE WILL LIKELY LOWER ALL
SITES TO IFR OR LOWER AT TIMES WEDNESDAY. STEADY PRECIPITATION
SHOULD TAPER TO SHOWERS LATE AFTERNOON INTO WEDNESDAY EVENING.
OUTLOOK...
WEDNESDAY NIGHT...MVFR IN RAIN...POSSIBLY SNOW NEAR ART.
THURSDAY...MVFR RAIN AND SNOW SHOWERS LIKELY.
FRIDAY...GENERALLY VFR.
SATURDAY...MVFR IN CHC OF SHOWERS.
SUNDAY...VFR/MVFR SCTD SNOW SHOWERS.
&&
.MARINE...
EASTERLY WINDS PICK UP ON THE LAKES LATER TONIGHT INTO WEDNESDAY
MORNING AS A WARM FRONT LIFTS NORTH ACROSS OHIO. WINDS AND WAVES
WILL INCREASE OVER WESTERN LAKE ONTARIO AND WILL WARRANT A SMALL
CRAFT ADVISORY FROM THE NIAGARA RIVER TO SODUS BAY. WINDS WILL VEER
TO THE SOUTH AND DIMINISH DURING THE AFTERNOON ON LAKE ERIE...WHILE
A MORE PERSISTENT EAST SOUTHEAST FLOW REMAINS IN PLACE ON LAKE
ONTARIO.
&&
.CLIMATE...
FEBRUARY 2012 HAS BEEN A PERSISTENTLY WARM MONTH...THOUGH NOT DAILY RECORD
WARMTH...THERE HAVE BEEN QUITE A NUMBER OF DAYS THIS MONTH THAT
HAVE REACHED OR EXCEEDED THE FREEZING MARK OF 32F. INCLUDING
TODAY`S MAXIMUM TEMPERATURE...BOTH BUFFALO AND ROCHESTER ARE
NEARING A RECORD NUMBER OF DAYS WITH 32F OR ABOVE MAXIMUM
TEMPERATURES THIS MONTH. WITH 2 DAYS REMAINING THIS FEBRUARY BOTH
CITIES MAY CLIMB HIGHER UP THE LIST. BELOW IS A LIST OF THE YEARS
WITH THE MOST AMOUNT OF FEBRUARY DAYS WITH FREEZING OR HIGHER
TEMPERATURES.
BUFFALO
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1998 25
2 2012 23
1884 23
4 1877 22
1890 22
AVG (1871-2012) 14.5
ROCHESTER
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1952 24
1998 24
3 2012 23
1931 23
1932 23
AVG (1871-2012) 15.0
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 5 AM TO NOON EST WEDNESDAY FOR
NYZ012>014-019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
LOZ042-043.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/WCH
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1256 AM EST WED FEB 29 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS OVERNIGHT AND MOVE
OFF THE COAST ON WEDNESDAY. A COLD FRONT WILL MOVE INTO THE
CAROLINAS WEDNESDAY NIGHT AND MAY LINGER NEAR OR JUST SOUTH OF
AREA BEFORE MOVING BACK NORTH AS A WARM FRONT ON FRIDAY. ANOTHER
STRONGER COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS ON
SATURDAY. COOLER AND DRIER HIGH PRESSURE WILL BUILD INTO THE AREA
SUNDAY INTO EARLY NEXT WEEK BRINGING TEMPERATURES BACK TO
SEASONABLE NORMS AFTER THE MID WEEK WARMTH.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1:00 AM WEDNESDAY...MID LEVEL DECK INCREASING IN COVERAGE
OVER THE EASTERN CAROLINAS AS EXPECTED. GOING FORECAST LOOKS
FINE...PREVIOUS DISCUSSION FOLLOWS:
SAT IMAGERY AND SFC OBS INDICATE MID LEVEL CLOUD DECK CONTINUES
JUST ON THE SW DOORSTEPS OF THE ILM CWA. MODEL SOUNDINGS INDICATE
PWS INCREASING FROM 1/2 INCH TO NEARLY 1 1/4 INCHES BY DAYBREAK
WEDNESDAY. WHAT THIS SAYS IS THAT THE CLOUDS ON THE WESTERN FRINGE
OF THE ILM CWA WILL FINALLY BE ABLE TO MAKE SOME FORWARD PROGRESS
ACROSS THE ILM CWA. LATEST HRRR MODEL RUNS INDICATE MUCH OF THE
PCPN FALLING APART AS IT APPROACHES THE ILM CWA FROM THE SW THRU W
DURING THE OVERNIGHT. WILL THERE4 RUN WITH THE IDEA OF NO POPS
OVERNIGHT EVEN THOUGH THE PASSAGE OF A DYNAMIC-LESS WARM FRONTAL
BOUNDARY WILL BE ONGOING. WILL EXTRAPOLATE THE AMOUNT OF
CLOUDINESS TO CROSS THE FORECAST AREA FOR THE REMAINDER OF THE
OVERNIGHT WITH THE USE OF SAT IMAGERY TRENDS. PROGGED 8H TEMPS AND
1K-8H THICKNESS INCREASE DRAMATICALLY BETWEEN 1 AM AND 7 AM
WEDNESDAY. COULD BE ONE OF THOSE NIGHTS WHERE THE LOWS ACTUALLY
OCCUR THIS EVENING...FOLLOWED BY TEMPS HOLDING STEADY OR SLOWLY
INCREASING DURING THE OVERNIGHT. COULD SEE ISOLATED -RA OR -SHRA
AHEAD OF THE WFP...OTHER THEN THAT...NO POPS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A PERIOD OF UNSETTLED WEATHER IS EXPECTED WED
INTO THU. A DEVELOPING WARM FRONT WILL MOVE ACROSS THE AREA WED
MORNING. A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA FROM THE
NW ON THU. AHEAD OF THE TROUGH...A DEEP SW TO WSW FLOW IS EXPECTED
TO DEVELOP. PRECIPITABLE WATER VALUES WILL INCREASE TO NEAR AN INCH
AND A HALF AS SW LOW LEVEL JET INCREASES TO 45 KT. TEMPS ON WED...
EVEN WITH CONSIDERABLE CLOUD COVER SHOULD FIND THEIR WAY INTO THE
70S AS H8 TEMPS CLIMB TO AROUND 13 DEG C. ALONG THE COAST...A
RESULTANT SEABREEZE WILL KEEP THE BEACHES COOLEST...UPPER 60S TO
LOWER 70S.
THE BEST SHORTWAVE ENERGY ASSOCIATED WITH THIS SYSTEM WILL TRAVEL TO
OUR DISTANT NORTH LATE WED NIGHT. HOWEVER...THERE SHOULD BE
SUFFICIENT LIFT IN THE WARM SECTOR...AHEAD OF THE TROUGH...TO BRING
A ROUND OF SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE A LIMITING
FACTOR AND MAINLY ELEVATED GIVEN THE BEST LIFT WILL ARRIVE DURING
THE LATE NIGHT AND EARLY MORNING HOURS. ALSO...A PRONOUNCED LOW
LEVEL INVERSION IS EXPECTED TO DEVELOP AROUND 1000 FT WHICH SHOULD
MAKE IT DIFFICULT FOR HIGHER WINDS ALOFT TO REACH THE SURFACE.
STILL...THE FORECAST AREA REMAINS IN A SLIGHT RISK FOR SEVERE
WEATHER LATE WED NIGHT INTO EARLY THU. STRONG STORMS ARE POSSIBLE
AND IT IS NOT IMPOSSIBLE FOR AN ISOLATED DAMAGING WIND GUST IN THE
STRONGEST STORMS.
TROUGH IS LIKELY TO GET HUNG UP JUST S OF THE FORECAST AREA AS IT
BECOMES PARALLEL TO THE FLOW. THIS WILL KEEP TEMPS WELL ABOVE NORMAL
THROUGH THE PERIOD WITH MORE 70S ON THU...AND AN 80 DEGREE READING
IS NOT OUT OF THE QUESTION AS DRIER AIR WORKS INTO THE AREA ALLOWING
FOR INCREASING SUNSHINE THROUGH THE AFTERNOON. A MORE WESTERLY
COMPONENT TO THE WIND DIRECTION WILL RESULT IN HIGHER TEMPS AT THE
BEACHES THU THAN ON WED. TEMPS BOTH NIGHTS WILL ALSO BE WELL ABOVE
NORMAL WITH WED NIGHT NOT GETTING BELOW THE UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...FOCUS FOR THE EXTENDED REMAINS ON THE FRONT
MOVING ACROSS THE SOUTHEAST SATURDAY THEN A COLDER AIRMASS AND
MINIMUM TEMPERATURES TUESDAY MORNING. HAVE INCREMENTALLY INCREASED
POPS FOR SATURDAY WITH CONFIDENCE A LITTLE HIGHER. STILL LOOKS LIKE
A SLOW TRUDGE ACROSS THE AREA AND WE HAVE POPS FOR SATURDAY AM
THROUGH SUNDAY AM.
BRIEF MID LEVEL TROUGHING MOVES ACROSS QUICKLY SUNDAY THROUGH
TUESDAY WITH A SECONDARY EMBEDDED SHORTWAVE LATE MONDAY INTO EARLY
TUESDAY. THIS FROM THE HPC FAVORED ECMWF. THE LATEST GFS HAS THIS
FEATURE EARLIER. IMPORTANT IMPACT ON LOWER TEMPERATURES TUESDAY
MORNING AS THE BOUNDARY LAYER SHOULD REMAIN WELL MIXED PREVENTING
RADIATIONAL CONDITIONS. ECMWF IS ALSO MORE AGGRESSIVE WITH THE QPF
AND WE MAY HAVE A FEW SPRINKLES/VIRGA TO CONTEND WITH.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH THE VALID PERIOD...WITH CONDITIONS
POSSIBLY DETERIORATING TO MVFR BEFORE DAYBREAK DUE TO FOG
DEVELOPMENT...AND ADDITIONALLY LOW CIGS AFTER MIDNIGHT THROUGH LATE
MORNING. CURRENT OBS DEPICT AN AREA OF MID TO HIGH LEVEL CLOUDS
SLOWLY INFILTRATING INTO THE SOUTHERN MOST TIP OF OUR AREA IN SC.
ANTICIPATE THESE CLOUDS TO CONTINUE THEIR MIGRATION INTO THE AREA
OVERNIGHT. WITH THE VARYING NATURE OF OPACITY WITH THESE
CLOUDS...THE CONFIDENCE OF TIMING AND OCCURRENCE OF FOG ATTM IS
MODERATE. FOR NOW...IF FOG DOES DEVELOP...BEST CHANCE WILL BE AT
KCRE/KLBT/KFLO AND WILL REMAIN EITHER 4-5SM AND LAST ONLY A FEW
HOURS. GENERALLY EAST WINDS OVERNIGHT WILL BE LIGHT. AFTER
DAYBREAK...LOW STRATOCUMULUS CLOUDS WILL LINGER BEFORE CIGS IMPROVE
TO VFR AGAIN BY LATE AFTERNOON...THOUGH EXPECT CLOUD COVER TO BE
BKN/OVC. CANNOT RULE OUT -DZ...HOWEVER HAVE NOT INTRODUCED INTO
CURRENT FORECAST GIVEN LOW CONFIDENCE. WINDS WILL GRADUALLY BECOME
SOUTHERLY...WITH GUSTS NEAR 20 KTS IN THE LATER AFTERNOON AND
SUBSIDING INTO THE EVENING HOURS. CIGS WILL LOWER AGAIN TOWARDS THE
END OF THE PERIOD CREATING MVFR/IFR CONDITIONS...AND POTENTIALLY
LIFR. HAVE INTRODUCED ISOLATED AREAS OF FOG WITH ENHANCED AREAS OF
MOISTURE...THOUGH CONFIDENCE IS LOW ATTM.
EXTENDED OUTLOOK... A CHANCE FOR PRECIP WEDNESDAY NIGHT INTO
THURSDAY MORNING WITH A COLD FRONT. BECOMING VFR THURSDAY. CHANCE OF
RAIN CONTINUES FOR FRIDAY AND SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:00 AM WEDNESDAY...LIGHT NE WINDS AND SEAS IN THE 2 TO 4 FT
RANGE CONTINUE ACROSS THE COASTAL WATERS. NO CHANGES TO GOING
FORECAST...PREVIOUS DISCUSSION FOLLOWS:
EXPECT NE-E WINDS THIS EVENING...AHEAD OF THE WARM FRONT. WINDS
WILL VEER TO THE SE THEN S AFTER THE WFP...WITH IT EXITING NORTH
OF THE LOCAL WATERS BY DAYBREAK WEDNESDAY. WIND SPEEDS WILL RANGE
BETWEEN 10 TO 15 KT...THEN INCREASE TO AROUND 15 KT AFTER THE WFP
DURING THE LATE PRE-DAWN HRS OF WEDNESDAY. SEAS WILL HOLD IN THE 2
TO 4 FT RANGE AND BEGIN TO BUILD DURING THE SHORT TERM.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...EASTERLY WINDS 10 KTS OR LESS WED MORNING
WILL VEER AROUND TO THE SOUTH AND INCREASE THROUGH WED AHEAD OF
APPROACHING TROUGH. SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY
LATE WED EVE INTO THE FIRST HALF OF THU. SW WINDS WILL INCREASE TO
20 TO 25 KTS WED NIGHT AHEAD OF COLD FRONT. THIS WILL BUILD SEAS
TO 6 TO 7 FT WITH SOME 8 FOOTERS OUT NEAR FRYING PAN SHOALS. WINDS
AND SEAS WILL DIMINISH ON THU AND THIS TREND WILL PERSIST THROUGH
THU NIGHT. WINDS ARE EXPECTED TO REMAIN FROM THE SW FOR MOST OF THE
PERIOD...PERHAPS BRIEFLY VEERING TO WSW LATE THU NIGHT.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...LIGHT FLOW INITIALLY WILL QUICKLY RAMP UP LATER
FRIDAY AND CONTINUE THROUGH SATURDAY AS A FRONT MOVES ACROSS THE
SOUTHEAST. EXPECT A SOUTHWESTERLY FLOW OF 20-25 KNOTS AND ALONG WITH
A SMALL CRAFT ADVISORY TO BEGIN EARLY SATURDAY. THE FRONT MOVES
ACROSS THE WATERS EARLY SUNDAY AND WITHOUT A STRONG SURGE OF COLD
AIR IN ITS WAKE...EXPECT A WESTERLY FLOW OF AROUND 15 KNOTS.
REGARDING SEAS...WILL SEE HIGHEST VALUES...WELL OVER SMALL CRAFT
CRITERIA LATE SATURDAY DIMINISHING WITH THE CHANGE IN FETCH SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
AVIATION...SGL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1141 PM CST TUE FEB 28 2012
.UPDATE...
ADJUSTED WARNING AREAS...ADDING WESTERN COUNTIES TO THE BLIZZARD
WARNING BASED ON LATEST OBS AND REPORTS FROM HAND COUNTY. ALSO ADDED IN
SOME MIXED PRECIP FOR SOUTHERN TIER COUNTIES FROM SPINK EASTWARD
TO GRANT COUNTY. A SECONDARY BAND OF PRECIP ON THE WARM CONVEYOR
SIDE OF THE STORM IS MAKING ITS WAY NORTH AND BRINGING FREEZING
RAIN...SLEET AND SNOW. LATEST RUC INDICATES THIS MIXED PRECIP WILL
LINGER THROUGH ABOUT 9 OR 10Z. OTHERWISE FROM ABERDEEN WEST ALL AREAS
ARE RECEIVING SNOW. WINDS HAVE SHIFTED AND ARE INCREASING OUT OF
THE NORTHWEST FROM THE MISSOURI RIVER VALLEY WEST. THIS TREND WILL
TRANSLATE EAST OVER THE NEXT 4 TO 5 HOURS.
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
STRONG SURFACE LOW PRESSURE AREA IN SOUTHWEST NEBRASKA MAKING ITS
MOVE LATE THIS AFTERNOON. GOOD AGREEMENT WITH THE MODELS NOW WITH
TAKING THIS SURFACE LOW PRESSURE AREA INTO SOUTHWEST MINNESOTA BY
WEDNESDAY MORNING AND INTENSIFYING IT. RADARS ACROSS THE REGION
NOW SHOWING INCREASING ECHOES AND COVERAGE WITH THE INTENSE LIFT
IN ASSOCIATION WITH THE UPPER AND SURFACE LOW PRESSURE AREAS. HAD
REPORTS OF SNOW...RAIN AND FREEZING RAIN THIS AFTERNOON. THINK ALL
OF THE PRECIPITATION WILL CHANGE OVER TO ALL SNOW THROUGH THE
EVENING HOURS AND AFTER MIDNIGHT ACROSS NORTHEAST SD AND WEST
CENTRAL MN. EXPECT WIDESPREAD SNOW AND BLOWING SNOW OVERNIGHT AND
THROUGH MUCH OF THE DAY WEDNESDAY. WINDS ARE EXPECTED TO BECOME
ALL NORTH THROUGH THE NIGHT AND INCREASE TO 25 TO 35 MPH WITH
WIDESPREAD BLIZZARD CONDITIONS EXPECTED. LEFT ALL WARNINGS AS IS
THROUGH WEDNESDAY AFTERNOON.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
EARLY WEDNESDAY NIGHT SFC LOW IS CONTINUING TO MOVE EAST THROUGH
WISCONSIN WITH STILL A SMALL CHANCE FOR LIGHT SNOW ACROSS THE FAR
EASTERN CWA. THROUGH THE OVERNIGHT HOURS SFC LOW WILL CONTINUE
MOVING EASTWARD TOWARDS THE GREAT LAKES AND WILL BRING AN END TO
THE SNOW CHANCES. WEAK SHORTWAVE TRACKS THROUGH THE DAKOTAS ON
THURSDAY WITH MAJORITY OF SNOWFALL REMAINING ACROSS ND. WILL KEEP
SMALL CHANCES ACROSS NORTHERN SD AS SOUTHERN EDGE OF SYSTEM LOOKS
TO AFFECT THIS AREA...BUT ANY AMOUNTS LOOK TO BE RATHER LIGHT.
ANOTHER SHORTWAVE MOVES THROUGH FRIDAY AND FRIDAY NIGHT AND WILL
LEAVE SMALL POPS IN FOR THIS AS WELL. DRY CONDITIONS AT THIS TIME
FOR THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AREAS SOUTH AND EAST OF KABR ARE CURRENTLY BEING IMPACTED BY A
SECONDARY CONVECTIVE BAND OF PRECIP ON THE WARM CONVEYOR SIDE OF
THE STORM SYSTEM. THIS IS PRODUCING A MIX OF FREEZING RAIN...SLEET
AND SNOW AT KABR AND IS LIKELY TO CONTINUE UNTIL AROUN 09 OR 10Z.
EAST WINDS IN THIS BELT ARE VERY GUSTY AT 25 TO 35 KTS. KMBG/KPIR
WINDS HAVE SHIFTED TO THE NORTHWEST AND ARE GUSTING TO AROUND 30
KTS CREATING LIFR CONDITIONS IN SNOW AND BLOWING SNOW. THESE WINDS
WILL TRANSLATE EASTWARD TONIGHT. EXPECT ALL SITES TO BE IFR UNTIL AROUND
18Z IN THE WEST AND 21Z IN THE EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING UNTIL 6 PM CST /5 PM MST/ WEDNESDAY FOR BROWN-
CAMPBELL-CORSON-DAY-DEWEY-EDMUNDS-FAULK-HUGHES-HYDE-
MARSHALL-MCPHERSON-POTTER-ROBERTS-STANLEY-SULLY-WALWORTH.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR BUFFALO-CLARK-
CODINGTON-DEUEL-GRANT-HAMLIN-HAND-JONES-LYMAN-SPINK.
MN...BLIZZARD WARNING UNTIL 6 PM CST WEDNESDAY FOR BIG STONE-TRAVERSE.
&&
$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...MOHR
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1102 PM CST TUE FEB 28 2012
.DISCUSSION.../ISSUED AT 925 PM CST/
TEMPERATURES AND PRECIPITATION TYPE CONTINUE TO BE THE MAIN FOCUS
THIS EVENING...WITH THE VAST MAJORITY OF THE CWA WITHIN A FEW
DEGREES OF FREEZING. THE INITIAL WARM FRONTAL BAND OF MOISTURE WHICH
PRODUCED HEAVY RAINFALL REGIONWIDE HAS EXITED TO THE NORTH AND WAS
REPLACED BY LINGERING LIGHT RAIN SHOWERS AND DRIZZLE. WITH
TEMPERATURES NEAR FREEZING...ICING OF VEGETATION AND UNTREATED
SURFACES WAS COMMON...ESPECIALLY TO THE NORTH OF I90. THE NEXT
CONVECTIVE BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS HAS LIFTED
NORTHWARD FROM NEBRASKA AND IS TRACKING NORTHEAST INTO THE I29
CORRIDOR. EXPECT THESE THUNDERSTORMS TO CONTINUE INTO NW IA AND SW
MINNESOTA OVER THE NEXT SEVERAL HOURS. HEAVY RAINFALL AND PEA SIZED
HAIL WILL BE ASSOCIATED WITH THIS BAND...WHICH HAS CAUSED A FEW
REPORTS OF DAMAGE TO ICE COVERED TREE BRANCHES. LATEST SHORT RANGE
MODELS ARE POINTING TOWARDS A SLIGHTLY SLOWER ARRIVAL OF THE COLDER
AIR AND RESULTANT CHANGE OVER TO SNOW...IN PARTICULAR INTO THE I29
CORRIDOR...SO HAVE BACKED OFF ON THAT TIMING BY AROUND 2 OR 3 HOURS.
ADDITIONALLY...THINK THAT VERY LITTLE ADDITIONAL WARMING WILL OCCUR
THROUGH MIDNIGHT...SO HAVE ADJUSTED TEMPERATURES THIS EVENING TO
REMAIN FAIRLY STEADY STATE. ALSO SLOWED THE EASTWARD PROGRESSION OF
THE SUB FREEZING TEMPERATURES. EVEN WITH THESE CHANGES...HEADLINES
LOOK IN PRETTY GOOD SHAPE.
&&
.AVIATION.../FOR THE 06Z TAFS/
PRECIP TYPE AND THUNDERSTORMS ARE THE NEAR-TERM CHALLENGES THIS
TAF PERIOD. ELEVATED INSTABILITY AXIS HAD SHIFTED EAST OF THE
INTERSTATE 29 CORRIDOR FROM KFSD TO KSUX BY 05Z. EMBEDDED
THUNDERSTORM POTENTIAL WILL HAVE SUBSIDED FOR THE MOST PART BY
06Z...WHEN THE INSTABILITY WANES NOTABLY. AS FAR AS PRECIPITATION
TYPES GO...HAVE LEANED TOWARD THE RUC AND SREF WHICH DEPICT
SLIGHTLY SLOWER TRANSITIONS TO ALL SNOW FOR KFSD AND KSUX /10Z-
12Z/. WINDS WILL ALSO SHIFT TO THE NORTH/NORTHWEST AROUND THE TIME
THE CHANGEOVER TO SNOW OCCURS...AFTER WHICH SUSTAINED SPEEDS OF 30
MPH WITH GUSTS TO 40 MPH WILL BECOME COMMON...AND PERSIST THROUGH
WEDNESDAY. COULD EVEN SEE PEAK GUSTS TO AROUND 45 MPH ON
WEDNESDAY. VSBY REDUCTIONS WITH THE WIND AND SNOW WILL THEREFORE
BE A CONCERN AS WELL...BUT GENERALLY THINK 1-2SM WILL BE
APPROPRIATE. AS FAR AS CIGS ARE CONCERNED...EXPECTED THE IFR DECK
TO PREVAIL THROUGH WEDNESDAY...ALTHOUGH IMPROVEMENT TO OVC015
/MVFR/ IS POSSIBLE DURING THE AFTERNOON. WINDS BEGIN TO SUBSIDE
AROUND/AFTER 00Z THURSDAY...WITH SCATTERING OF THE LOW CLOUDS
BETWEEN 06Z AND 12Z THURSDAY.
&&
.PREV DISCUSSION.../ISSUED AT 300 PM CST/
MADE VERY FEW CHANGES TO THE EXISTING HEADLINES...OTHER THAN ADDING
IN A WIND ADVISORY FOR MUCH OF THE AREA WEDNESDAY. TEMPERATURES
HOVERING RIGHT AROUND THE FREEZING MARK IS CAUSING SOME FREEZING OF
EXPOSED SURFACES AND SIDEWALKS BUT THE ROADS SO FAR HAVE REMAINED
ONLY SPOTTY ICY. FAIRLY HIGH RAIN RATES WILL CONTINUE INTO THE
EVENING WITH CONVECTION EXPECTED ALONG THE FAR SOUTHERN CWA THROUGH
ABOUT 4Z SO EXPECT THIS WILL AID IN HIGH...AROUND 0.10 INCH PER HOUR
RAIN RATES THROUGH THIS TIME. TEMPERATURES WILL REMAIN STEADY OR
SLOWLY RISE THROUGH THE EARLY PART OF THE NIGHT...THEN FALL AS THE
FRONT PASSES LATER TONIGHT AND COLDER AIR WRAPS IN. THIS IS ALSO
WHEN THE BEST CHANCE FOR SNOW IS AND STILL THINKING ABOUT 4 INCHES
WITHIN THE WARNING AREA THROUGH OUR NW ZONES. IN ADDITION...PRETTY
STRONG WINDS ARE STILL LIKELY...ADMITTEDLY ONLY A MARGINAL WARNING
BUT CLOSE ENOUGH NOT TO SWITCH TO AN ADVISORY. WINDY AND MIXY ON
WEDNESDAY WITH AREAS OF BLOWING SNOW IN THE NORTHERN PART OF THE
CWA. TEMPERATURES SHOULD WARM INTO MAINLY THE LOWER TO MIDDLE 30S.
EXPECT NORTHWEST WINDS BEHIND THIS VERY STRONG LOW OF ABOUT 30 TO 40
MPH THROUGH THE DAY. /08
FURTHER OUT...REALLY NOT A LOT HAPPENING AT THIS POINT. SURFACE
RIDGE BEGINS TO SHIFT EASTWARD THROUGH THE NIGHT ON WEDNESDAY
NIGHT...WHICH MAY STEADY OUT OUR TEMPERATURES AS THE NIGHT
PROGRESSES. THIS IS FOLLOWED BY A DECENT WAVE PASSING BY ON THURSDAY
NOTED BY THE UPPER QG FORCING AND PV. THIS SHORT WAVE IS ON THE
SOUTHEAST SIDE OF A CLOSED LOW IN SOUTHERN SASKATCHEWAN AND LIFTS
NORTHEASTWARD THROUGH THIS AREA. THIS FAR SOUTH IN OUR FORECAST
AREA...MEASURABLE PRECIPITATION WILL VERY LIKELY BE HARD TO FIND DUE
TO DRY AIR BELOW 700MB. THEREFORE OPTED TO GO DRY...BUT WOULD NOT BE
SURPRISED IF A FEW FLURRIES FELL THROUGHOUT OUR NORTHERN ZONES ON
THURSDAY...JUST NOT ENOUGH TO WORRY ABOUT RIGHT NOW. HIGHS ON
THURSDAY WILL BE MILD IN OUR FAR SOUTHERN ZONES...WELL INTO THE
40S...WHERE THICKER CLOUD COVER WILL BE THE LEAST PREVALENT. BUT
ALONG AND NORTH OF I90...CLOUDS WILL LIKELY HOLD TEMPERATURES IN THE
30S.
ON THURSDAY NIGHT AND FRIDAY...ALL MODELS POINT TO THE
AFOREMENTIONED CLOSED UPPER LOW MOVING INTO THE NORTHERN TIER OF THE
U.S. WITH VARYING DEGREES OF TIMING AND STRENGTH. THE NEXT WAVE ALSO
TRAVELS NORTHEASTWARD ON THE SOUTH SIDE OF THE UPPER LOW...BUT NOW
APPEARS TO BE AFFECTING AREAS TO THE SOUTH OF OUR FORECAST AREA. THE
MODELS HAVE BEEN TRENDING TOWARD A MORE SOUTHERLY SOLUTION WITH THIS
FEATURE FOR SEVERAL RUNS NOW...SO DECIDED TO ELIMINATE POPS FOR OUR
SOUTHERN ZONES. BECAUSE OF THE LACK OF PRECIPITATION NOW EXPECTED...
THE SIOUX CITY AND STORM LAKE AREAS MAY WARM TO NEAR 40 NOW...
COOLING OFF HEADING NORTHWARD TO AROUND 30 IN OUR NORTHERN ZONES.
NOT A LOT GOING ON IN THE EXTENDED. THE UPPER LOW MOVES EASTWARD
INTO SOUTHEAST CANADA THROUGH THE WEEKEND WHICH WILL BE FOLLOWED BY
RIDGING THROUGHOUT THE WESTERN U.S.. THIS WILL BE HIGHLIGHTED BY A
WARMUP ACROSS OUR AREA EARLY NEXT WEEK ONCE THE CHILLY SURFACE HIGH
EXITS EASTWARD. RIGHT NOW...THE EXTENDED LOOKS DRY. /MJF
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR IAZ001>003-
012>014-020>022-031-032.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR MNZ071-072-
080-081-097.
WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR MNZ089-090-098.
NE...WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR NEZ013-014.
SD...WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR SDZ040-050-
055>060-063>065.
WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR SDZ061-062-
066>071.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR SDZ038-039-
052>054.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1146 PM CST TUE FEB 28 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...WINTER STORM MOVING ALONG MORE OR LESS AS EARLIER
FORECAST. SURFACE LOW IS A BIT FURTHER SOUTH THAN THE 12Z MODELS
DEPCITED WITH BEST PRESSURE FALLS AT 03Z SUGGESTING IT WILL MOVE
TOWARDS LA CROSSE BY NOON TOMORROW. NAM FORECAST SOUNDINGS
VERIFIED BEST AGAINTS THE 00Z GRB AND MPX RADIOSONDES. IF THESE
FORECAST SOUNDINGS FOR OUR FORECAST AREA ARE ACCURATE THEN OUR
CURRENT ADVISORIES AND WARNINGS ARE WELL PLACED. SOME CONCERN THAT
WOOD, PORTAGE AND WAUPACA COUNTIES COULD GET MORE THAN SIX INCHES
OF SNOW IF IT STAYS SNOW THROUGH MOST OF THE NIGHT BUT ALL OF THE
MODELS BRING AN ELEVATED ABOVE FREEZING LAYER AROUND 850MB ACROSS
THAT AREA BY 06Z OR SO WHICH WOULD CHANGE THE SNOW OVER TO SLEET
OR FREEZING RAIN. DRY AIR NEAR THE LAKE MICHIGAN SHORE IS DELAYING
ARRIVAL OF PRECIPITATION BUT IT WILL GET THERE. SNOW WAS FALLING
OVER ALL OF THE AREA WITH THE EXCEPTION OF SOUTHERN WINNEBAGO
COUNTY WHERE IS WAS RAINING AND PARTS OF CALUMET COUNTY WHERE SOME
LIGHT FREEZING RAIN WAS REPORTED.
RDM
&&
.PREV DISCUSSION...ISSUED AT 644 PM CST TUE FEB 28 2012...
SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY INDICATES LOW
PRESSURE EMERGING FROM THE ROCKIES INTO WESTERN KANSAS THIS AFTERNOON...WITH
ITS ASSOCIATED WARM FRONT LIFTING NORTH ALONG THE KS/NE BORDER AND
ACROSS MISSOURI. CONVECTION HAS DEVELOPED ALREADY AHEAD OF THE LOW
JUST AHEAD OF A POTENT DRY SLOT PUNCHING INTO NEBRASKA. CLOSER TO
HOME...LEADING EDGE OF RETURN MOISTURE IS NOW PUSHING INTO SOUTHERN
WISCONSIN A TAD AHEAD OF SCHEDULE...AS EVIDENT BY A BAND OF RAIN AND
SNOW. EARLIER MODERATE SNOW OVER N-C WISCONSIN IS HANGING ON ALONG
THE U.P. BORDER WHERE THEY RECEIVED 2-3 INCHES OF SNOW. BUT THE
MAIN PROBLEM FOR THIS FORECAST IS THE LOW OUT WEST AND HEAVY SNOW
POTENTIAL AS IT MOVES ACROSS THE REGION TONIGHT INTO WEDNESDAY.
TONIGHT...LOW PRESSURE OVER THE PLAINS WILL MOVE NORTHEAST AND
OCCLUDE AS IT MOVES INTO SOUTHWEST MINNESOTA BY 12Z WEDNESDAY.
AHEAD OF THE LOW...A 40-50KT LLJ WILL RAMP UP AND SHIFT INTO
NORTHERN ILLINOIS DURING THE OVERNIGHT HOURS. THIS LLJ WILL
TRANSPORT RICH GULF OF MEXICO MOISTURE NORTHEAST WITH PWATS OF
UPWARDS OF 0.75 INCHES REACHING INTO CENTRAL WISCONSIN. THIS IS
OVER 200 PCT OF NORMAL AND 2 STANDARD DEVIATIONS ABOVE NORMAL.
BEFORE THIS OCCURS THOUGH...LEADING EDGE OF THE RETURN MOISTURE ON
THE 285K SURFACE IS CREATING A BAND OF LIGHT RAIN AND SNOW WHICH
SHOULD APPROACH CENTRAL WISCONSIN LATE THIS AFTERNOON AND INTO THE
FOX VALLEY BY EARLY IN THE EVENING. WET BULB TEMPS HAVE BEEN RISING
THIS AFTERNOON...BUT FIGURING SNOW OVER CENTRAL WISCONSIN...AND
RAIN/SNOW MIX OVER EAST-CENTRAL WHERE ONSHORE FLOW WILL CONTINUE.
THE MAIN SURGE OF PRECIPITATION SHOULD NOT ARRIVE UNTIL LATE INTO
THE EVENING AND THE OVERNIGHT HOURS WHEN FORCING VIA LLJ AND
MID-LEVEL FGEN LIFTS INTO THE REGION. WITH MID-LEVEL LAPSE RATES OF
6.5-7 C/KM AND NEGATIVE EPV ABOVE THE FGEN LAYER...CONVECTION IS
DEFINITELY POSSIBLE WITH THE PRECIPITATION OVERNIGHT...AND UPSTREAM
OBS BEAR THIS OUT AS WELL. THERMAL PROFILES VARY WIDELY BETWEEN THE
WARMER GFS AND THE COLDER ECMWF/NAM. ALTHOUGH THERE IS PLENTY OF
WARM AIR TO OUR SOUTH...THE WARM LAYER IS MARGINALLY HIGH AT AROUND
800MB WHICH LEAVES THE POTENTIAL FOR CONVECTION TO WIPE OUT THAT
WARM NOSE...THEREBY KEEPING THE PROFILE NEAR OR JUST BELOW FREEZING
OVER CENTRAL AND EAST-CENTRAL WISCONSIN. AS A RESULT...HAVE BOOSTED
SNOW AMOUNTS OVER CENTRAL WISCONSIN AND THE NORTHERN FOX VALLEY. AM
MOST CONFIDENT OF RAIN/SLEET MIXING IN OVER KEWAUNEE AND MANITOWOC
COUNTIES THANKS TO THE LAKE INFLUENCE. SE WINDS WILL ALSO RAMP UP
OVERNIGHT WHICH COULD CREATE NEAR WHITE OUT VSBYS AT TIMES WITHIN
THE HEAVY SNOW. WILL UPGRADE DOOR COUNTY TO WARNING CRITERIA...AS
THEY DO SURPRISINGLY WELL IN CASES LIKE THIS...WHERE COLDER AIR AT
925MB WILL HANG ON THE LONGEST. OTHERWISE...CURRENT HEADLINES LOOK
GOOD FOR WARNING/ADVISORY CONFIGURATION. THE NEXT SHIFT WILL HAVE
TO MONITOR FOR UPGRADES FOR THE NEXT ROW OF COUNTIES SOUTH OF THE
WARNING IF CONVECTION DOES COOL THE COLUMN ENOUGH FOR A MOSTLY SNOW
PTYPE.
WEDNESDAY...OCCLUDED LOW PRESSURE WILL SLOW AND MOVE FROM SW
MINNESOTA TO WESTERN WISCONSIN OVER THE COURSE OF THE DAY. LOW
LEVEL WARM AIR WILL CONTINUE TO WRAP AROUND THE LOW INTO EASTERN
WISCONSIN DURING THE MORNING...WHILE THE DRY SLOW MOVES IN ALOFT.
MODERATE TO HEAVY SNOW WILL BE WIDESPREAD NORTH AND WEST OF THE DRY
SLOT OVER NORTHERN AND NORTHWEST WISCONSIN FOR MUCH OF THE MORNING.
BUT FARTHER SOUTH...THE DRY SLOT WILL MAKE IT DIFFICULT FOR ICE
CRYSTALS TO GET INTRODUCED INTO THE CLOUD...SO HAVE ADDED THE CHANCE
OF FREEZING DRIZZLE OVER CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
RAIN OR DRIZZLE SHOULD BE MIXING WITH SNOW BY THE TIME OF THE
MORNING COMMUTE OVER THE FOX VALLEY AND LAKESHORE WHICH LOOKS TO BE
A SLOPPY MESS. SHOULD ALSO SEE A PERIOD OF OF JUST RAIN/DRIZZLE AS
WELL...MID-MORNING THROUGH MID-AFTERNOON BEFORE COLDER AIR SURGES
EAST AS IT WRAPS AROUND THE LOW. WITH ALL THIS IN MIND...TOTAL
SNOWFALL ACCUMULATION THROUGH 00Z THU LOOKS LIKE 10-15 INCHES OVER
N-C WISCONSIN...6-10 NORTH OF A MARSHFIELD TO STURGEON BAY
LINE...AND 3-7 INCHES FOR CENTRAL WISCONSIN AND MUCH OF THE FOX
VALLEY. DID END HEADLINES EARLY FOR THE FOX VALLEY AND
LAKESHORE...AS SNOW CHANGING TO RAIN SHOULD CAUSE CONDITIONS TO
RAPIDLY IMPROVE BY 18Z WED.
LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
PERIOD TO SEE SHIFT FROM OUR SPLIT FLOW PATTERN TO A MORE
CONSOLIDATED FLOW WITH TROF SHIFTING EAST THROUGH THE LAKES REGION
THIS WEEKEND. TEMPS FOR SAT AND SUN EXPECTED TO BE AOB NORMS. RIDGE
TO FOLLOW FOR MUCH OF THE WORK WEEK FOR A DRY AND MILD PERIOD.
WED NIGHT TO THU...STORM TO BE EXITING THE AREA WITH SNOW ENDING
WEST TO EAST. LEFT OUT OF GRIDS AT THIS TIME...THOUGH MODEL
SOUNDINGS INDICATE SOME FREEZING DRIZZLE POSSIBLE OVER THE EAST
BEHIND SYSTEM. WEAK HIGH PRESSURE MOVES THROUGH DURING DAY
THU...SMALL CHANCE OF LAKE EFFECT FAR NW VILAS IN THE MORNING
THOUGH SUPPORT FOR THAT WEAKENS BY AFTERNOON.
THU NIGHT TO FRIDAY...MODELS STILL HAVING DIFFICULTY THIS
PERIOD...THOUGH STARTING TO GEL A BIT. TROF OF LOW
PRESSURE/DEVELOPING COLD FRONT MOVES EAST INTO STATE LATE THU
NIGHT. SIG WAA AHEAD OF SYSTEM AND SOME FGEN SAYS KEEP SMALL
POPS...MAINLY NORTH...UPPER SUPPORT WEAK THOUGH. ALL MODELS WANT TO
DEVELOP WAVE ON FRONT SOUTH OF STATE...BRING IT NE ALONG FRONT.
MOST TO OUR EAST...THOUGH GFS REMAINS CONSISTENT BRINGING LOW
THROUGH STATE. EITHER WAY KEPT CHANCE POPS HIGHEST EAST. SOME
CONCERN WITH PCPN TYPE...WILL GO FOR MIX EAST...THOUGH LATEST EC
BRINGING COLDER AIR FURTHER EAST.
WEEKEND...HINTS AT POSSIBLE CLIPPER SYSTEM SUN...AND POSSIBLE
LAKE EFFECT FAR NORTHWEST CWA WITH NORTHWEST FLOW.
&&
.AVIATION...MAINLY IFR TO LIFR CONDITIONS DUE TO HEAVY SNOW ACROSS
NORTHERN WISCONSIN TODAY...BEFORE GRADUALLY IMPROVING TO MVFR
CONDITIONS THROUGH. AREAS ROUGHLY SOUTH OF A LINE FROM AUW TO SUE
CAN EXPECT MAINLY MVFR CIGS AND VSBYS DUE TO SNOW/SLEET/FREEZING
RAIN AND RAIN TODAY BEFORE CHANGING BACK TO ALL LIGHT SNOW TONIGHT
WITH MVFR CONDITIONS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ038>040-
048>050.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ035>037-
045.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ005-010>013-
018>021-030-031-073-074.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1003 PM CST TUE FEB 28 2012
.UPDATE...WINTER STORM MOVING ALONG MORE OR LESS AS EARLIER
FORECAST. SURFACE LOW IS A BIT FURTHER SOUTH THAN THE 12Z MODELS
DEPCITED WITH BEST PRESSURE FALLS AT 03Z SUGGESTING IT WILL MOVE
TOWARDS LA CROSSE BY NOON TOMORROW. NAM FORECAST SOUNDINGS
VERIFIED BEST AGAINTS THE 00Z GRB AND MPX RADIOSONDES. IF THESE
FORECAST SOUNDINGS FOR OUR FORECAST AREA ARE ACCURATE THEN OUR
CURRENT ADVISORIES AND WARNINGS ARE WELL PLACED. SOME CONCERN THAT
WOOD, PORTAGE AND WAUPACA COUNTIES COULD GET MORE THAN SIX INCHES
OF SNOW IF IT STAYS SNOW THROUGH MOST OF THE NIGHT BUT ALL OF THE
MODELS BRING AN ELEVATED ABOVE FREEZING LAYER AROUND 850MB ACROSS
THAT AREA BY 06Z OR SO WHICH WOULD CHANGE THE SNOW OVER TO SLEET
OR FREEZING RAIN. DRY AIR NEAR THE LAKE MICHIGAN SHORE IS DELAYING
ARRIVAL OF PRECIPITATION BUT IT WILL GET THERE. SNOW WAS FALLING
OVER ALL OF THE AREA WITH THE EXCEPTION OF SOUTHERN WINNEBAGO
COUNTY WHERE IS WAS RAINING AND PARTS OF CALUMET COUNTY WHERE SOME
LIGHT FREEZING RAIN WAS REPORTED.
RDM
&&
.PREV DISCUSSION...ISSUED AT 644 PM CST TUE FEB 28 2012...
SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY INDICATES LOW
PRESSURE EMERGING FROM THE ROCKIES INTO WESTERN KANSAS THIS AFTERNOON...WITH
ITS ASSOCIATED WARM FRONT LIFTING NORTH ALONG THE KS/NE BORDER AND
ACROSS MISSOURI. CONVECTION HAS DEVELOPED ALREADY AHEAD OF THE LOW
JUST AHEAD OF A POTENT DRY SLOT PUNCHING INTO NEBRASKA. CLOSER TO
HOME...LEADING EDGE OF RETURN MOISTURE IS NOW PUSHING INTO SOUTHERN
WISCONSIN A TAD AHEAD OF SCHEDULE...AS EVIDENT BY A BAND OF RAIN AND
SNOW. EARLIER MODERATE SNOW OVER N-C WISCONSIN IS HANGING ON ALONG
THE U.P. BORDER WHERE THEY RECEIVED 2-3 INCHES OF SNOW. BUT THE
MAIN PROBLEM FOR THIS FORECAST IS THE LOW OUT WEST AND HEAVY SNOW
POTENTIAL AS IT MOVES ACROSS THE REGION TONIGHT INTO WEDNESDAY.
TONIGHT...LOW PRESSURE OVER THE PLAINS WILL MOVE NORTHEAST AND
OCCLUDE AS IT MOVES INTO SOUTHWEST MINNESOTA BY 12Z WEDNESDAY.
AHEAD OF THE LOW...A 40-50KT LLJ WILL RAMP UP AND SHIFT INTO
NORTHERN ILLINOIS DURING THE OVERNIGHT HOURS. THIS LLJ WILL
TRANSPORT RICH GULF OF MEXICO MOISTURE NORTHEAST WITH PWATS OF
UPWARDS OF 0.75 INCHES REACHING INTO CENTRAL WISCONSIN. THIS IS
OVER 200 PCT OF NORMAL AND 2 STANDARD DEVIATIONS ABOVE NORMAL.
BEFORE THIS OCCURS THOUGH...LEADING EDGE OF THE RETURN MOISTURE ON
THE 285K SURFACE IS CREATING A BAND OF LIGHT RAIN AND SNOW WHICH
SHOULD APPROACH CENTRAL WISCONSIN LATE THIS AFTERNOON AND INTO THE
FOX VALLEY BY EARLY IN THE EVENING. WET BULB TEMPS HAVE BEEN RISING
THIS AFTERNOON...BUT FIGURING SNOW OVER CENTRAL WISCONSIN...AND
RAIN/SNOW MIX OVER EAST-CENTRAL WHERE ONSHORE FLOW WILL CONTINUE.
THE MAIN SURGE OF PRECIPITATION SHOULD NOT ARRIVE UNTIL LATE INTO
THE EVENING AND THE OVERNIGHT HOURS WHEN FORCING VIA LLJ AND
MID-LEVEL FGEN LIFTS INTO THE REGION. WITH MID-LEVEL LAPSE RATES OF
6.5-7 C/KM AND NEGATIVE EPV ABOVE THE FGEN LAYER...CONVECTION IS
DEFINITELY POSSIBLE WITH THE PRECIPITATION OVERNIGHT...AND UPSTREAM
OBS BEAR THIS OUT AS WELL. THERMAL PROFILES VARY WIDELY BETWEEN THE
WARMER GFS AND THE COLDER ECMWF/NAM. ALTHOUGH THERE IS PLENTY OF
WARM AIR TO OUR SOUTH...THE WARM LAYER IS MARGINALLY HIGH AT AROUND
800MB WHICH LEAVES THE POTENTIAL FOR CONVECTION TO WIPE OUT THAT
WARM NOSE...THEREBY KEEPING THE PROFILE NEAR OR JUST BELOW FREEZING
OVER CENTRAL AND EAST-CENTRAL WISCONSIN. AS A RESULT...HAVE BOOSTED
SNOW AMOUNTS OVER CENTRAL WISCONSIN AND THE NORTHERN FOX VALLEY. AM
MOST CONFIDENT OF RAIN/SLEET MIXING IN OVER KEWAUNEE AND MANITOWOC
COUNTIES THANKS TO THE LAKE INFLUENCE. SE WINDS WILL ALSO RAMP UP
OVERNIGHT WHICH COULD CREATE NEAR WHITE OUT VSBYS AT TIMES WITHIN
THE HEAVY SNOW. WILL UPGRADE DOOR COUNTY TO WARNING CRITERIA...AS
THEY DO SURPRISINGLY WELL IN CASES LIKE THIS...WHERE COLDER AIR AT
925MB WILL HANG ON THE LONGEST. OTHERWISE...CURRENT HEADLINES LOOK
GOOD FOR WARNING/ADVISORY CONFIGURATION. THE NEXT SHIFT WILL HAVE
TO MONITOR FOR UPGRADES FOR THE NEXT ROW OF COUNTIES SOUTH OF THE
WARNING IF CONVECTION DOES COOL THE COLUMN ENOUGH FOR A MOSTLY SNOW
PTYPE.
WEDNESDAY...OCCLUDED LOW PRESSURE WILL SLOW AND MOVE FROM SW
MINNESOTA TO WESTERN WISCONSIN OVER THE COURSE OF THE DAY. LOW
LEVEL WARM AIR WILL CONTINUE TO WRAP AROUND THE LOW INTO EASTERN
WISCONSIN DURING THE MORNING...WHILE THE DRY SLOW MOVES IN ALOFT.
MODERATE TO HEAVY SNOW WILL BE WIDESPREAD NORTH AND WEST OF THE DRY
SLOT OVER NORTHERN AND NORTHWEST WISCONSIN FOR MUCH OF THE MORNING.
BUT FARTHER SOUTH...THE DRY SLOT WILL MAKE IT DIFFICULT FOR ICE
CRYSTALS TO GET INTRODUCED INTO THE CLOUD...SO HAVE ADDED THE CHANCE
OF FREEZING DRIZZLE OVER CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
RAIN OR DRIZZLE SHOULD BE MIXING WITH SNOW BY THE TIME OF THE
MORNING COMMUTE OVER THE FOX VALLEY AND LAKESHORE WHICH LOOKS TO BE
A SLOPPY MESS. SHOULD ALSO SEE A PERIOD OF OF JUST RAIN/DRIZZLE AS
WELL...MID-MORNING THROUGH MID-AFTERNOON BEFORE COLDER AIR SURGES
EAST AS IT WRAPS AROUND THE LOW. WITH ALL THIS IN MIND...TOTAL
SNOWFALL ACCUMULATION THROUGH 00Z THU LOOKS LIKE 10-15 INCHES OVER
N-C WISCONSIN...6-10 NORTH OF A MARSHFIELD TO STURGEON BAY
LINE...AND 3-7 INCHES FOR CENTRAL WISCONSIN AND MUCH OF THE FOX
VALLEY. DID END HEADLINES EARLY FOR THE FOX VALLEY AND
LAKESHORE...AS SNOW CHANGING TO RAIN SHOULD CAUSE CONDITIONS TO
RAPIDLY IMPROVE BY 18Z WED.
LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
PERIOD TO SEE SHIFT FROM OUR SPLIT FLOW PATTERN TO A MORE
CONSOLIDATED FLOW WITH TROF SHIFTING EAST THROUGH THE LAKES REGION
THIS WEEKEND. TEMPS FOR SAT AND SUN EXPECTED TO BE AOB NORMS. RIDGE
TO FOLLOW FOR MUCH OF THE WORK WEEK FOR A DRY AND MILD PERIOD.
WED NIGHT TO THU...STORM TO BE EXITING THE AREA WITH SNOW ENDING
WEST TO EAST. LEFT OUT OF GRIDS AT THIS TIME...THOUGH MODEL
SOUNDINGS INDICATE SOME FREEZING DRIZZLE POSSIBLE OVER THE EAST
BEHIND SYSTEM. WEAK HIGH PRESSURE MOVES THROUGH DURING DAY
THU...SMALL CHANCE OF LAKE EFFECT FAR NW VILAS IN THE MORNING
THOUGH SUPPORT FOR THAT WEAKENS BY AFTERNOON.
THU NIGHT TO FRIDAY...MODELS STILL HAVING DIFFICULTY THIS
PERIOD...THOUGH STARTING TO GEL A BIT. TROF OF LOW
PRESSURE/DEVELOPING COLD FRONT MOVES EAST INTO STATE LATE THU
NIGHT. SIG WAA AHEAD OF SYSTEM AND SOME FGEN SAYS KEEP SMALL
POPS...MAINLY NORTH...UPPER SUPPORT WEAK THOUGH. ALL MODELS WANT TO
DEVELOP WAVE ON FRONT SOUTH OF STATE...BRING IT NE ALONG FRONT.
MOST TO OUR EAST...THOUGH GFS REMAINS CONSISTENT BRINGING LOW
THROUGH STATE. EITHER WAY KEPT CHANCE POPS HIGHEST EAST. SOME
CONCERN WITH PCPN TYPE...WILL GO FOR MIX EAST...THOUGH LATEST EC
BRINGING COLDER AIR FURTHER EAST.
WEEKEND...HINTS AT POSSIBLE CLIPPER SYSTEM SUN...AND POSSIBLE
LAKE EFFECT FAR NORTHWEST CWA WITH NORTHWEST FLOW.
&&
.AVIATION...CONDITIONS WILL FALL TO IFR FROM WEST TO EAST THIS
EVENING AS WINTER STORM APPROACHES FROM THE CENTRAL PLAINS. MOSTLY
SNOW EXPECTED OVERNIGHT NORTH OF A WAUSAU TO STURGEON BAY LINE
WITH A MIXTURE OF SNOW...SLEET AND FREEZING RAIN FURTHER SOUTH.
SNOW ILL CONTINUE WEDNESDAY NORTH OF RHINELANDER WITH SCATTERED
LIGHT RAIN OR DRIZZLE FURTHER SOUTH. CIGS MAY FALL TO NEAR
AIRFIELD MINIMUMS LATE TONIGHT AND WEDNESDAY.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ038>040-
048>050.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ035>037-
045.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ005-010>013-
018>021-030-031-073-074.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
621 AM CST WED FEB 29 2012
.DISCUSSION...
610 AM CST
TRENDS BECOMING MORE CLEAR IN TERMS OF CLOUDS AND TEMPS OVER THE
NEXT FEW HOURS. HAVE MADE SOME ADJUSTMENTS TO THE NEAR TERM
FORECAST TO ACCOUNT FOR THESE LATEST TRENDS. WARM FRONTAL BOUNDARY
CONTINUES TO LIFT NORTHEASTWARD AND STRETCHES FROM ROUGHLY
PRINCETON TO KANKAKEE TO LAFAYETTE. TEMPS BEHIND IT HAVE QUICKLY
WARMED INTO THE UPPER 50S TO AROUND 60 DEGREES. HAVE WARMED UP
NORTHERN AREAS TO AROUND 50/LOWER 50S AS THEY SHOULD BE IN THE
WARM SECTOR FOR A SHORT TIME IN THE NEXT FEW HOURS. THE FIRST COOL
FRONT IS RIGHT ON THE HEELS OF THE WARM FRONT BRINGING MUCH DRIER
AND MODESTLY COOLER AIR WITH STATIONS IN WEST CENTRAL ILLINOIS AND
SOUTHEAST IOWA HAVING COOLED SEVERAL DEGREES OVER THE LAST HOUR OR
TWO. THE CHALLENGE WILL BE DETERMINING HOW MUCH WARMING MAY OCCUR
AS THE SUN COMES UP AND MIXING DEEPENS THIS MORNING BEHIND THIS
BOUNDARY AND AHEAD OF THE BETTER PUSH OF COOLER AIR THIS
AFTERNOON. SOUTHWESTERN AREAS MAY SEE A PEAK IN TEMPS NOW WITH A
LOSS OF A FEW DEGREES OVER THE NEXT FEW HOURS...WITH A REBOUND IN
TEMPS AS SUNSHINE INCREASES LATE THIS MORNING. SPEAKING OF
SUN...SUNSHINE IS ON THE WAY WITH STRATUS QUICKLY ERODING
NORTHEASTWARD AND MOST OF THE CWA SHOULD SEE SUNSHINE IN THE NEXT
COUPLE HOURS. HAVE TWEAKED AFTERNOON TEMP TRENDS AS WELL TO SHOW A
BIT BETTER DEFINED COOLING LATE BUT HOURLY TEMP TRENDS MAY NEED
ADJUSTMENTS LEADING UP TO THAT TIME.
MDB
&&
.PREV DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* ENDING OF RAIN AROUND 12Z.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 12Z...
RAIN HAS MOVED NE AND ENDED DURING THE PREDAWN AS STRONG MID AND
UPPER DRYING SPREAD INTO THE AREA WITH THE CORE OF A 135KT JET
MAX CROSSING THE MID MS VALLEY. IFR/LIFR PREVAILS ACROSS THE LOCAL
AREA AS THE SURFACE WARM FRONT IS STILL S OF THE TERMINALS...FROM
NE IL SOUTHEASTWARD TO CENTRAL IND AT 11Z.
ANTICIPATE QUICK IMPROVEMENT TO VFR DURING THE EARLY MORNING AS
THE WARM FRONT LIFTS N OF MDW AND ORD. WARM FRONTAL PASSAGE TO
RESULT IN THE WINDS VEERING FROM SE TO S WHILE STRENGTHENING AND
BECOMING QUITE GUSTY FROM THE WSW AFTER THE SYSTEM/S COLD FRONT
MOVES QUICKLY ACROSS THE AREA THIS MORNING.
METARS FROM SITES OF THE WARM FROM SHOW WIDESPREAD 20-25KT GUSTS
AND LOCAL 25-30KT GUSTS. AMDAR DATA FROM EARLY MORNING FLIGHT
INTO AND OUT OF RFD AND ORD SHOW WINDS QUICKLY VEER TO OUT OF THE
SW WITH HEIGHT...AND REACH 50KT WITHIN 3K FT OF THE GROUND...
WHICH IS THE TOP OF THE LOW LEVEL INVERSION IS LOCATED N OF THE
WARM FRONT. RAPID CLEARING OUT OF CLOUDS AS THE WARM FRONT MOVES
N WILL ALLOW GOOD SURFACE HEATING WITH GOOD OVERTURNING IN THE
BOUNDARY LAYER EFFICIENT TRANSFER OF MOMENTUM OF STRONG WINDS
ALOFT DOWN TO THE GROUND AND GUSTS 35-40KT LIKELY BY LATE
MORNING.
THE UPPER LOW CURRENTLY OVER THE EXTREME NW CORNER OF IA WILL MOVE
NORTHEASTWARD TO OVER CENTRAL WI BY LATE AFTERNOON...AND THE E TO
THE CENTRAL GREAT LAKES BY 06Z WED. AS THE SYSTEM MOVES FROM WI
INTO THE WESTERN GREAT LAKES LATE THIS AFTERNOON AND EARLY THIS
EVENING LOW LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE RATES WRAP S
AND SE AROUND IT. THIS WILL BRING MVFR CLOUDS AND SOME -SN/-SHSN
TO THE AREA FOR THE EVENING.
WITH THE CENTER OF THE SYSTEM MOVING FARTHER E ACROSS THE GREAT
LAKES LATER THIS EVENING AND OVERNIGHT THE PRESSURE GRADIENT OVER
THE LOCAL AREA WILL LESSEN SIGNIFICANTLY...WITH WINDS DROPPING OFF
DURING THE EVENING AND ESPECIALLY OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS EARLY THIS MORNING INTO
THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
* HIGH CONFIDENCE IN MVFR CIGS FROM EARLY EVENING THROUGH TONIGHT.
* MEDIUM CONFIDENCE IN PERIOD OF MVFR VISIBILITIES THIS EVENING IN
-SHSN.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. WX NIL.
FRIDAY...MVFR LOWERING TO IFR IN RA. CHANCE OF TS LATER IN THE
DAY. IFR CIGS IMPROVE TO MVFR BY EVENING. CHANCE OF -SN DURING
THE NIGHT.
SATURDAY...VFR. WX NIL
SUNDAY...VFR. CHANCE OF -SN.
MONDAY...VFR. WX NIL.
TUESDAY...VFR. WX NIL.
TRS
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039 UNTIL 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 9
PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
601 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* ENDING OF RAIN AROUND 12Z.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 12Z...
RAIN HAS MOVED NE AND ENDED DURING THE PREDAWN AS STRONG MID AND
UPPER DRYING SPREAD INTO THE AREA WITH THE CORE OF A 135KT JET
MAX CROSSING THE MID MS VALLEY. IFR/LIFR PREVAILS ACROSS THE LOCAL
AREA AS THE SURFACE WARM FRONT IS STILL S OF THE TERMINALS...FROM
NE IL SOUTHEASTWARD TO CENTRAL IND AT 11Z.
ANTICIPATE QUICK IMPROVEMENT TO VFR DURING THE EARLY MORNING AS
THE WARM FRONT LIFTS N OF MDW AND ORD. WARM FRONTAL PASSAGE TO
RESULT IN THE WINDS VEERING FROM SE TO S WHILE STRENGTHENING AND
BECOMING QUITE GUSTY FROM THE WSW AFTER THE SYSTEM/S COLD FRONT
MOVES QUICKLY ACROSS THE AREA THIS MORNING.
METARS FROM SITES OF THE WARM FROM SHOW WIDESPREAD 20-25KT GUSTS
AND LOCAL 25-30KT GUSTS. AMDAR DATA FROM EARLY MORNING FLIGHT
INTO AND OUT OF RFD AND ORD SHOW WINDS QUICKLY VEER TO OUT OF THE
SW WITH HEIGHT...AND REACH 50KT WITHIN 3K FT OF THE GROUND...
WHICH IS THE TOP OF THE LOW LEVEL INVERSION IS LOCATED N OF THE
WARM FRONT. RAPID CLEARING OUT OF CLOUDS AS THE WARM FRONT MOVES
N WILL ALLOW GOOD SURFACE HEATING WITH GOOD OVERTURNING IN THE
BOUNDARY LAYER EFFICIENT TRANSFER OF MOMENTUM OF STRONG WINDS
ALOFT DOWN TO THE GROUND AND GUSTS 35-40KT LIKELY BY LATE
MORNING.
THE UPPER LOW CURRENTLY OVER THE EXTREME NW CORNER OF IA WILL MOVE
NORTHEASTWARD TO OVER CENTRAL WI BY LATE AFTERNOON...AND THE E TO
THE CENTRAL GREAT LAKES BY 06Z WED. AS THE SYSTEM MOVES FROM WI
INTO THE WESTERN GREAT LAKES LATE THIS AFTERNOON AND EARLY THIS
EVENING LOW LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE RATES WRAP S
AND SE AROUND IT. THIS WILL BRING MVFR CLOUDS AND SOME -SN/-SHSN
TO THE AREA FOR THE EVENING.
WITH THE CENTER OF THE SYSTEM MOVING FARTHER E ACROSS THE GREAT
LAKES LATER THIS EVENING AND OVERNIGHT THE PRESSURE GRADIENT OVER
THE LOCAL AREA WILL LESSEN SIGNIFICANTLY...WITH WINDS DROPPING OFF
DURING THE EVENING AND ESPECIALLY OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS EARLY THIS MORNING INTO
THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
* HIGH CONFIDENCE IN MVFR CIGS FROM EARLY EVENING THROUGH TONIGHT.
* MEDIUM CONFIDENCE IN PERIOD OF MVFR VISIBILITIES THIS EVENING IN
-SHSN.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. WX NIL.
FRIDAY...MVFR LOWERING TO IFR IN RA. CHANCE OF TS LATER IN THE
DAY. IFR CIGS IMPROVE TO MVFR BY EVENING. CHANCE OF -SN DURING
THE NIGHT.
SATURDAY...VFR. WX NIL
SUNDAY...VFR. CHANCE OF -SN.
MONDAY...VFR. WX NIL.
TUESDAY...VFR. WX NIL.
TRS
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 9
PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
427 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* ENDING OF RAIN EARLY PREDAWN.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 06Z...
A VERY SLOPPY WX PICTURE EVOLVING WITH MULTIPLE WX CONCERNS. A LOW
PRESSURE SYSTEM IS DEEPENING OVER THE UPPER MISSOURI VALLEY WILL
TURN EAST TRACK THROUGH SRN MN/WI TOMORROW. THIS SYSTEM IS DRAWING
MOISTURE NWD FROM THE GLFMEX...AND OVERRUNNING AN ASSOCIATED WARM
FRONT EXTENDING THROUGH SRN IOWA TO SRN IL/IN. WIDESPREAD RAIN HAS
OVERSPREAD THE AREA...WITH THE LATEST RADAR IMAGERY SHOWING MORE
CONVECTIVE ELEMENTS AND SCT TS ALONG AND SOUTH OF THE WARM FRONT.
AT ISSUANCE TIME...CONDITIONS WILL BE APPROACHING MVFR LEVELS AND
EXPECT CIGS/VIS TO DROP TO MVFR BY AROUND MIDNIGHT. THERE WILL BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT ISOLD/EMBEDDED TS...BUT
COVERAGE SHOULD BE SPARSE AND HAVE LITTLE CONFIDENCE ON ANY TIMING
OR DURATION OF TS AT THE TERMINALS. SO...WILL CONTINUE TO LIMIT
THE TS MENTION IN THE TAFS TO JUST VCTS AND CB GROUPS. CONFIDENCE
IS HIGHER ON THE OTHER IMPACTS ON SERVICE IN THE POTENTIAL FOR IFR
CONDITIONS AS THE WARM FRONT LIFTS NWRD THROUGH NRN IL EARLY
TOMORROW MORNING. THERE IS ALSO SOME CONCERN IN THE POSSIBILITY OF
STRONGER...MORE LINEAR TS DEVELOPING WITH THE COLD FRONT PASSAGE.
THE SHORT RANGE MODEL GUIDANCE INDICATES THAT THE COLD FRONT
SHOULD QUICKLY PUSH THROUGH THE AREA TOMORROW MORNING BTWN 12-16Z.
THERE ARE INDICATIONS OF THE POTENTIAL FOR INCREASED SURFACE BASED
INSTABILITY AND A WARM SECTOR ENVIRONMENT PUSHING QUICKLY THROUGH
THE AREA BETWEEN THE TIME THAT THE WARM FRONT LIFTS TO THE NORTH
AND THE COLD FRONT SWEEPS EWD ACROSS IL/IN. THIS WOULD PROVIDE A
BRIEF WINDOW OF OPPORTUNITY FOR STRONGER TS TO DEVELOP...BUT
CONFIDENCE IN TIMING IS LOW. FOLLOWING THE PASSAGE OF THE SFC COLD
FRONT...DRY AIR ALOFT WILL OVERRIDE A MOIST LAYER BLW 5KFT...SO A
PERIOD OF DZ WITH IFR CIGS/VIS IS LIKELY THOUGH ARND 18Z. ALSO
FOLLOWING THE FROPA...WINDS WILL VEER SWLY AND QUICKLY STRENGTHEN
THROUGH THE MORNING...WITH GUSTS OF 35KT...OR POSSIBLY
HIGHER...ARE EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.
BY LATE TOMORROW EVENING...WRAPAROUND MOISTURE AND CYCLONIC FLOW
ALOFT ALONG WILL COOLER AIR FILTERING INTO THE AREA BEHIND THE
EXITING LOW WILL BRING BACK MVFR CIGS AND SOME LIGHT SNOW. WITH
THE COLD CORE UPPER LOW MOVING OVER SRN WI DURG THE
EVENING...THERE MAY BE ENOUGH INSTABILITY FOR SOME HEAVIER SNOW
SHOWERS OR GRAUPEL WITH THE LIGHT SNOW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS THIS MORNING INTO
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR. WX NIL.
FRIDAY...MVFR CIGS/VIS. RAIN OR A RAIN/SNOW MIX LIKELY DURING THE
DAY...CHANCE OF LIGHT SNOW AT NIGHT.
SATURDAY...VFR...SLIGHT CHANCE OF LIGHT SNOW OR FLURRIES EARLY...STRONG
GUSTY GUSTY W WINDS IN THE AFTERNOON.
SUNDAY...VFR. SLIGHT CHANCE LIGHT SNOW EARLY.
MONDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...8 AM
WEDNESDAY TO 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1050 AM EST WED FEB 29 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 291200Z TAFS/...
1350Z UPDATE...NOT REALLY SEEING THE MFVR MATERIALIZING UPSTREAM
AND THINKING ABOUT REMOVING IT FROM THE TAFS. PREVIOUS DISC FOLLOWS...
LINE OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY PUSHING THROUGH EASTERN ILLINOIS. EXTRAPOLATION OF
FEATURE SUGGESTS IT SHOULD BE EAST OF KHUF/KLAF AROUND ISSUANCE
TIME...AND EAST OF KIND/KBMG BY 291300Z. THINK CONVECTIVE THREAT
WILL REMAIN RATHER HIGH UNTIL THIS FEATURE PASSES...AS SHORT TERM
MODEL DATA SHOW GOOD ELEVATED INSTABILITY AHEAD OF FEATURE ALONG
WITH 60-65 KT LOW LEVEL JET OVERHEAD.
APPEARS BROAD SURFACE FRONT LAGS A FEW HOURS BEHIND UPPER SYSTEM.
AT THIS POINT...DON/T EXPECT TOO MUCH ACTIVITY TO DEVELOP ALONG
ACTUAL FRONT DUE TO WEAK LOW LEVEL CONVERGENCE AND GENERAL
DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM. WILL HOLD ONTO MVFR
CEILINGS UNTIL FRONTAL PASSAGE FROM LATE MORNING UNTIL AROUND
MIDDAY...WITH CEILINGS SCATTERING OUT AFTER THAT.
GOOD POTENTIAL FOR SURFACE WIND GUSTS AROUND 35 KTS FROM 230-250
HEADINGS TO DEVELOP TOWARDS MIDDAY AS MID LEVEL JET MOVES OVERHEAD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/SMF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
951 AM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF WIDESPREAD RAIN IS DIMINISHING FROM THE WEST AS UPPER LEVEL
SHORT WAVE MOVES RAPIDLY EAST ALONG THE WARM FRONT. WILL REDUCE POPS
FOR THE NEXT SEVERAL HOURS IN OHIO AS A RESULT. BLEND OF RECENT
RADAR AND SURFACE DATA COUPLED WITH RECENT HRRR AND WRF- NMM MODEL
OUTPUT SHOW SCATTERED THUNDERSTORMS EMBEDDED IN THIS RAIN SHIELD.
SO A CHANCE OF THUNDERSTORMS WILL BE INCLUDED IN THE ENTIRE FORECAST
AREA FOR THE REMAINDER OF THE DAY.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER, SO INITIALLY THE
THUNDERSTORMS WOULD BE MORE THE ELEVATED KIND, ALTHOUGH LIGHTNING
DATA SHOWS SOME CLOUD TO GROUND STRIKES. HOWEVER, DURING THE AFTERNOON,
THE SURFACE LAYER BECOMES WELL MIXED, SO CONVECTION THEN, BE IT
SHOWERS OR THUNDERSTORMS, CAN GENERATE GUSTY SURFACE WINDS, AND
THIS APPEARS TO BE THE BASIS OF SPC`S SLIGHT RISK OF SEVERE
THUNDERSTORMS TODAY FOR SOUTHERN PARTS OF THE UPPER OHIO VALLEY.
FORECASTED TEMPERATURES CLOSE TO GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
658 AM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR AND SURFACE DATA SHOW LIGHT RAIN, ASSOCIATED WITH THE
INCOMING LOW PRESSURE SYSTEM, SPREADING EASTWARD THROUGH THE UPPER
OHIO VALLEY. SURFACE DATA SHOWS TEMPERATURES ACROSS THE ENTIRE AREA
ARE WARMER THAN FREEZING AND DEW POINTS ARE RISING QUICKLY FROM THE
SOUTHWEST. BECAUSE OF THIS, HAVE CANCELLED THE FREEZING RAIN
ADVISORY.
BLEND OF RECENT RADAR AND SURFACE DATA COUPLED WITH RECENT HRRR
AND WRF-NMM MODEL OUTPUT SHOW SCATTERED THUNDERSTORMS EMBEDDED IN
THIS RAIN SHIELD. SO HAVE ADDED A CHANCE OF THUNDERSTORMS TO BE
SPREADING EASTWARD DURING TODAY. ADJUSTED RAIN AMOUNTS CLOSER TO
HPC AND RFC GUIDANCE.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER, SO INITIALLY THE
THUNDERSTORMS WOULD BE MORE THE ELEVATED KIND, ALTHOUGH LIGHTNING
DATA SHOWS SOME CLOUD TO GROUND STRIKES. HOWEVER, DURING THE AFTERNOON,
THE SURFACE LAYER BECOMES WELL MIXED, SO CONVECTION THEN, BE IT
SHOWERS OR THUNDERSTORMS, CAN GENERATE GUSTY SURFACE WINDS, AND
THIS APPEARS TO BE THE BASIS OF SPC`S SLIGHT RISK OF SEVERE
THUNDERSTORMS TODAY FOR SOUTHERN PARTS OF THE UPPER OHIO VALLEY.
FORECASTED TEMPERATURES CLOSE TO GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
537 AM CST WED FEB 29 2012
.UPDATE...
AVIATION DISCUSSION UPDATED FOR 12Z TAF ISSUANCE BELOW.
ADJUSTED WARNING AREAS...ADDING WESTERN COUNTIES TO THE BLIZZARD
WARNING BASED ON LATEST OBS AND REPORTS FROM HAND COUNTY. ALSO
ADDED IN SOME MIXED PRECIP FOR SOUTHERN TIER COUNTIES FROM SPINK
EASTWARD TO GRANT COUNTY. A SECONDARY BAND OF PRECIP ON THE WARM
CONVEYOR SIDE OF THE STORM IS MAKING ITS WAY NORTH AND BRINGING
FREEZING RAIN...SLEET AND SNOW. LATEST RUC INDICATES THIS MIXED
PRECIP WILL LINGER THROUGH ABOUT 9 OR 10Z. OTHERWISE FROM ABERDEEN
WEST ALL AREAS ARE RECEIVING SNOW. WINDS HAVE SHIFTED AND ARE
INCREASING OUT OF THE NORTHWEST FROM THE MISSOURI RIVER VALLEY
WEST. THIS TREND WILL TRANSLATE EAST OVER THE NEXT 4 TO 5 HOURS.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
THE FORECAST CHALLENGES ARE BECOMING FEWER THIS MORNING...AND
MAINLY INCLUDE SNOW ACCUMULATIONS AND WHERE THE EASTERN FRINGE OF
BLIZZARD CONDITIONS END UP SETTING UP TODAY...ALONG WITH
TEMPERATURES AND MINUSCULE PRECIPITATION CHANCES GLANCING THE
NORTHERN TIER COUNTIES THURSDAY AND FRIDAY.
CURRENTLY...A 987HPA SURFACE LOW PRESSURE CENTER IS PUSHING INTO
SOUTHWESTERN MINNESOTA. THE UPPER LOW CIRCULATION CENTER IS NOTED
IN RADAR AND SATELLITE IMAGERY OVER THE VERY NORTHWEST CORNER OF
IOWA AT THIS TIME. UNDER A CLOUDY SKY AND ONGOING MODERATE TO
HEAVY SNOW...TEMPERATURES HAVE BEEN HOLDING IN THE TEENS AND 20S
ACROSS THE MISSOURI RIVER VALLEY...WITH READINGS IN THE UPPER 20S
TO LOWER 30S ACROSS THE JAMES RIVER VALLEY EASTWARD INTO THE RED
RIVER VALLEY. NORTHWEST WIND SPEEDS HAVE ALSO MARKEDLY INCREASED
ACROSS THE MISSOURI RIVER VALLEY EARLY THIS MORNING INTO THE 15 TO
30 MPH RANGE WITH GUSTS UP TO 40 MPH NOTED SO FAR.
WITH THE PRELIMINARY REPORTS OF SNOWFALL AND BLIZZARD CONDITIONS
ACROSS THE WEST LATE LAST EVENING INTO EARLY THIS MORNING...ALONG
WITH REPORTS OF SNOW AND ICE AND SLEET ACCUMULATION ACROSS
PORTIONS OF THE JAMES RIVER VALLEY UP ONTO THE PRAIRIE COTEAU AND
EAST INTO THE RED RIVER VALLEY...HAVE DECIDED TO MAKE ONLY A
COUPLE OF MODEST ADJUSTMENTS THIS MORNING TO THE WINTER STORM
HEADLINES. THE BLIZZARD WARNING WAS EXTENDED INTO
JONES/LYMAN/BUFFALO AND HAND COUNTIES LATE LAST EVENING...AND
SPINK COUNTY HAS BEEN ADDED TO THE BLIZZARD HEADLINE EARLY THIS
MORNING...GIVEN THE REPORTS OF BLIZZARD CONDITIONS OUT WEST AND
THE EXPECTED SPREAD OF BLIZZARD CONDITIONS OVER INTO THE JAMES
RIVER VALLEY TODAY. EAST OF THE JAMES RIVER...THOUGH...WIND SPEEDS
BECOME A BIT MORE MARGINAL FOR BLIZZARD CONDITIONS...SO OPTED TO
REPLACE THE BLIZZARD WARNING OVER MARSHALL/DAY/ROBERTS/BIG
STONE/TRAVERSE COUNTIES WITH A WINTER STORM WARNING HEADLINE.
THESE COUNTIES WILL SEE WINTER STORM WARNING CRITERIA MET /HEAVY
SNOW ACCUMULATIONS AS WELL AS A MIX OF ICE AND SNOW ACCUMULATIONS/
BEFORE THEY SEE BLIZZARD WARNING CRITERIA MET. SO THE CHANGES WERE
MADE WITH THIS MORNING`S PACKAGE.
WELL...LAST NIGHT`S MODEL SOLUTIONS DID A GOOD JOB OF DEPICTING
THE INITIAL WAA-FORCED BROAD DEFORMATION ZONE BAND OF MODERATE TO
HEAVY THAT SET UP ACROSS THE NORTHERN TIER COUNTIES YESTERDAY
AFTERNOON THROUGH EARLY THIS MORNING...ALONG WITH THE FREEZING
RAIN/SLEET THREAT ACROSS THE SOUTHEASTERN THIRD OF FORECAST ZONES
LAST EVENING THROUGH EARLY THIS MORNING...AND THEY DID
SURPRISINGLY WELL TO DENOTE THE STRONG COLD-AIR INSTABILITY
INFLUENCED POTENTIALLY SIGNIFICANT TROWAL-FORCED SECONDARY BAND OF
SNOW ACROSS EAST CENTRAL INTO NORTHEAST SOUTH DAKOTA AND WEST
CENTRAL MINNESOTA. THAT IS WHAT IS ONGOING PER RADAR AND SATELLITE
IMAGERY THIS MORNING. NICE COMMA HEAD NOTED IN SATELLITE IMAGERY
WHERE COLD/DRY TONGUE DRY SLOT INFLUENCED AIR IS WRAPPING BACK
AROUND ON ITSELF AS IT COLLIDES INTO THE WARM CONVEYOR BELT
/TROWAL/ ON THE NORTH AND EAST SIDE OF THIS LOW PRESSURE SYSTEM.
THERE WILL LIKELY CONTINUE TO BE OCCASIONAL PERIODS OF INCH AN
HOUR SNOW RATES THIS MORNING ACROSS THE EASTERN CWA AS THIS TROWAL
BAND OF SNOW BEGINS TO PIVOT AROUND THE UPPER LOW. SEE WSW FOR
SNOW AMOUNT DETAILS.
THIS SYSTEM IS PULLING AWAY FROM THE REGION BY LATE THIS
AFTERNOON...AND CONDITIONS SHOULD BE IMPROVING MARKEDLY THIS
AFTERNOON OUT WEST INTO THIS EVENING OUT EAST. A FEW MORE RATHER
WEAK S/WS RIPPLE EASTWARD THROUGH THE UPPER FLOW THURSDAY INTO
FRIDAY...BUT FRIDAY LOOKS TO BE THE BEST SHOT AT SOME CAA-FORCED
SNOW SHOWERS OR SNOW FLURRIES. NO OTHER NOTEWORTHY CHANGES MADE TO
TEMPERATURES OR WINDS THROUGH THE SHORT TERM.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM FORECAST
PERIOD. A MAINLY DRY NORTHWEST FLOW ALOFT IS EXPECTED TO TRANSITION
OVER THE AREA FRIDAY NIGHT AND CONTINUE THROUGH THE WEEKEND. A
FAST MOVING CLIPPER TROUGH IS EXPECTED TO SLIDE SEWD IN THE NW FLOW
THROUGH ERN SD SATURDAY AFTERNOON...BUT WITH MOST ATMOSPHERIC
FORCING REMAINING JUST EAST OF THE AREA...ONLY ANTICIPATING AN INCREASE IN
CLOUDS ALONG WITH A COLD FRONTAL PASSAGE/AIRMASS CHANGE. TRENDED
FORECAST TOWARD THE MORE RUN TO RUN CONSISTENT ECMWF AND GEM
SOLUTIONS. ON SUNDAY...THE NW FLOW ALOFT TRANSLATES EASTWARD AND
H5 HEIGHTS RISE RAPIDLY. THE LOW LEVELS WILL BE SLOW TO RESPOND TO
THE INCREASED HEIGHTS/UPPER LEVEL WARMING SUNDAY BUT AS H5 HEIGHTS
CONTINUE TO RISE MONDAY...LOW LEVELS AND SFC RESPOND IN ERNEST.
TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH
SUNDAY...WARMING TO ABOVE AVERAGE LEVELS FOR MONDAY AND TUESDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MAJOR WINTER STORM SYSTEM CONTINUES EARLY THIS MORNING WITH MVFR/IFR
CONDITIONS AT ALL TERMINALS. EXPECT MAINLY IFR CONDITIONS IN LIGHT
TO MODERATE SNOW TO BE THE RULE UNTIL THE EARLY AFTERNOON AT
KPIR/KMBG AND DURING THE EARLY EVENING HOURS AT KABR/KATY. IFR/MVFR
CIGS ARE ANTICIPATED AT KABR/KATY THROUGH THE LATE EVENING HOURS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
BROWN-BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-
HUGHES-HYDE-JONES-LYMAN-MCPHERSON-POTTER-SPINK-STANLEY-
SULLY-WALWORTH.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR CLARK-
CODINGTON-DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS.
MN...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR BIG STONE-
TRAVERSE.
&&
$$
SHORT TERM...DORN
LONG TERM...CHURCH
AVIATION...CHURCH
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
400 AM CST WED FEB 29 2012
.DISCUSSION.../ISSUED AT 359 AM CST/
SURFACE LOW PRESSURE IS CENTERED JUST TO THE SOUTH OF SIOUX FALLS
VERY EARLY THIS MORNING AND CONTINUING TO PUSH TO THE NORTHEAST. DRY
SLOT HAS PUSHED AS FAR NORTH AS THE EASTERN I 90 CORRIDOR...WITH
MIXED PRECIPITATION FALLING TO THE NORTH OF THIS...AND MOST LIKELY
GETTING SOME ICING OVER PORTIONS OF EAST CENTRAL SOUTH DAKOTA INTO
SOUTHWESTERN MINNESOTA WHERE TEMPERATURES ARE HOVERING AROUND
FREEZING. BACK TO THE WEST...LIGHT SNOW IS OCCURRING FROM
NORTHEASTERN SOUTH DAKOTA WRAPPING SOUTHWESTWARD ALL THE WAY BACK
INTO NORTH CENTRAL NEBRASKA IN VICINITY OF DEVELOPING TROWAL...WITH
THIS AREA SLOWLY PROGRESSING EASTWARD AS COLDER AIR FILTERS IN
BEHIND THE LOW. HURON AND MITCHELL HAVE BOTH CHANGED OVER TO SNOW
OVER THE PAST HOUR AND EXPECT THIS EASTWARD TREND TO CONTINUE
THROUGH THE EARLY MORNING HOURS...WITH MOST PLACES CHANGING TO ALL
SNOW BY AROUND 12Z. WILL SEE AN ADDITIONAL 1 TO POSSIBLY 2 INCHES OF
SNOW NORTH OF I 90 TODAY AS THE TROWAL PULLS EAST AND SLOWLY WEAKENS
THROUGH THE DAY...WITH LESSER AMOUNTS TO THE SOUTH. AS
EXPECTED...ALREADY SEEING NORTHWESTERLY WINDS PICK UP ON THE
BACKSIDE OF THE LOW AND WITH THIS TREND ALSO CONTINUING THROUGH THE
DAY WILL HAVE AREAS OF BLOWING SNOW ACROSS OUR WEST AND NORTH INTO
THE AFTERNOON. IN TERMS OF HEADLINES...PRETTY MUCH LEFT THEM AS
IS...THOUGH DID REMOVE HANSON AND HUTCHINSON COUNTIES FROM THE
WINTER WEATHER ADVISORY AS THINKING THAT ANY ADDITIONAL SNOWFALL
WILL BE AN INCH OR LESS IN THAT AREA...THOUGH IN TURN ADDED THEM TO
THE WIND ADVISORY OVER THE SOUTHEASTERN PORTION OF THE CWA. DO THINK
THE WIND ADVISORY IS MARGINAL ALONG THE NORTHERN MOST ROW OF
COUNTIES...ALONG THE I90 CORRIDOR...WHERE 0.5 KM WINDS ARE PROGGED
TO BE IN THE 35 TO 40 KT RANGE. CONFIDENCE IS A LITTLE HIGHER TO THE
SOUTH WITH 0.5 KM WINDS OF 40 TO 45 KTS THROUGH THE MISSOURI RIVER
CORRIDOR INTO NORTHWEST IOWA. ALSO CONSIDERED ALLOWING PORTIONS OF
THE SOUTHWESTERN MINNESOTA WINTER WEATHER ADVISORY TO EXPIRE EARLIER
THAN 18Z AS WE CURRENTLY HAVE IT WITH ADDITIONAL SNOWFALL FORECASTED
TO BE AN INCH OR LESS...BUT WITH MIXED PRECIPITATION AND SOME
PROBABLE ICING THIS MORNING..AND THE POSSIBILITY THAT SOME MIXED
PRECIPITATION COULD BE ONGOING AFTER 12Z...LEFT THE EXPIRATION TIME
AT 18Z. IN REGARD TO HIGH TEMPERATURES TODAY...WITH 925 MB TEMPS OF
-2 TO -4 C ACROSS THE AREA WILL SEE HIGHS IN THE LOWER TO MID 30S.
WINDS WILL DROP OFF BY LATE THIS EVENING AS THE LOW PULLS AWAY AND
THE GRADIENT RELAXES. WITH DECREASING CLOUDS LOWS WILL FALL INTO THE
MID AND UPPER TEENS ACROSS MUCH OF THE AREA...EXCEPT LOWER 20S ALONG
THE MISSOURI RIVER CORRIDOR. MAY SEE TEMPERATURES RISE A BIT IN OUR
WEST LATER AT NIGHT AS SOUTHERLY WINDS PICK UP IN ADVANCE OF AN
APPROACHING SURFACE TROUGH TO THE WEST.
THIS BOUNDARY WILL PUSH ACROSS THE REGION ON THURSDAY AS A MIDLEVEL
SHORTWAVE LIFTS UP OVER OUR EAST. IN SPITE OF THAT...LEFT IT DRY
WITH LOW LEVEL MOISTURE PRETTY SPARSE. WILL BE WARMER ON THURSDAY
WITH WARM AIR ADVECTION IN A SOUTHERLY FLOW OUT AHEAD OF THE
TROUGH...WITH HIGHS CLIMBING INTO THE MID 30S NORTH...TO MID 40S
THROUGH THE SIOUX CITY TO STORM LAKE CORRIDOR. COLDER AIR WILL
FILTER IN BEHIND THIS SYSTEM...LEADING TO A COOLER DAY ON FRIDAY
WITH HIGHS MAINLY IN THE 30S. THREW IN SOME FLURRIES ACROSS OUR
NORTHEAST ON FRIDAY NIGHT WITH MODELS HINTING AT IT AS A SHORTWAVE
DROPS SOUTHWARD ON A NORTHWESTERLY UPPER LEVEL FLOW DURING THAT TIME
FRAME.
NOT MUCH FOCUS PUT INTO THE EXTENDED WITH SHORT TERM ISSUES...BUT
MODELS POINTING TOWARD A BUILDING UPPER LEVEL RIDGE OVER OUR AREA
FOR THE WEEKEND INTO THE BEGINNING OF NEXT WEEK. WITH THAT...WILL
REMAIN PRIMARILY DRY WITH A SLOW WARMING TREND THROUGH THE PERIOD.
CONSENSUS NUMBERS WOULD HAVE US INTO THE 40S AND 50S FOR HIGHS BY
MONDAY AND TUESDAY.
&&
.AVIATION.../FOR THE 06Z TAFS/
PRECIP TYPE AND THUNDERSTORMS ARE THE NEAR-TERM CHALLENGES THIS
TAF PERIOD. ELEVATED INSTABILITY AXIS HAD SHIFTED EAST OF THE
INTERSTATE 29 CORRIDOR FROM KFSD TO KSUX BY 05Z. EMBEDDED
THUNDERSTORM POTENTIAL WILL HAVE SUBSIDED FOR THE MOST PART BY
06Z...WHEN THE INSTABILITY WANES NOTABLY. AS FAR AS PRECIPITATION
TYPES GO...HAVE LEANED TOWARD THE RUC AND SREF WHICH DEPICT
SLIGHTLY SLOWER TRANSITIONS TO ALL SNOW FOR KFSD AND KSUX /10Z-
12Z/. WINDS WILL ALSO SHIFT TO THE NORTH/NORTHWEST AROUND THE TIME
THE CHANGEOVER TO SNOW OCCURS...AFTER WHICH SUSTAINED SPEEDS OF 30
MPH WITH GUSTS TO 40 MPH WILL BECOME COMMON...AND PERSIST THROUGH
WEDNESDAY. COULD EVEN SEE PEAK GUSTS TO AROUND 45 MPH ON
WEDNESDAY. VSBY REDUCTIONS WITH THE WIND AND SNOW WILL THEREFORE
BE A CONCERN AS WELL...BUT GENERALLY THINK 1-2SM WILL BE
APPROPRIATE. AS FAR AS CIGS ARE CONCERNED...EXPECTED THE IFR DECK
TO PREVAIL THROUGH WEDNESDAY...ALTHOUGH IMPROVEMENT TO OVC015
/MVFR/ IS POSSIBLE DURING THE AFTERNOON. WINDS BEGIN TO SUBSIDE
AROUND/AFTER 00Z THURSDAY...WITH SCATTERING OF THE LOW CLOUDS
BETWEEN 06Z AND 12Z THURSDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ001>003-012>014-
020>022-031-032.
MN...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ089-090-098.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ071-072-080-
081-097.
NE...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ013-014.
SD...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ060>062-065>071.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR SDZ040-050-
055>059-063-064.
WINTER STORM WARNING UNTIL NOON CST TODAY FOR SDZ038-039-052>054.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
455 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE WILL PASS WELL WEST OF THE
REGION...RESULTING IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY. COOLER...DRY WEATHER WILL FOLLOW EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW AND MODEL PREFERENCE...
MEDIUM RANGE MODEL SUITE IN PRETTY GOOD AGREEMENT INTO THIS
WEEKEND...THEN SOME DIVERGENCE SEEN BEYOND SUNDAY NAMELY WITH A
POSSIBLE WEAK LOW THAT MAY PASS S OF NEW ENGLAND SUNDAY NIGHT OR
MONDAY TIMEFRAME WITH ANOTHER QUICK BATCH OF LIGHT PRECIP. OVERALL
THOUGH...LOOKS LIKE MOST OP MODELS SHOWING GENERAL AGREEMENT
AND...BETTER STILL AGREEMENT WITH MOST OF THEIR COMPANION ENSEMBLE
MEANS INTO EARLY NEXT WEEK WITH THE SETUP OF RIDGING ALONG THE
EASTERN SEABOARD.
THURSDAY NIGHT...UPPER LEVEL LOW AND ITS SURFACE REFLECTION
WEAKENS AS THEY WORK ACROSS NORTHERN NEW ENGLAND WITH SOME SURFACE
RIDGING BUILDING DOWN THE COAST. MAY SEE LEFTOVER PRECIP LINGER
ALONG THE E COAST WITH ONSHORE FLOW. OTHERWISE...SHOULD SEE
GENERAL IMPROVEMENT OVERNIGHT.
FRIDAY-FRIDAY NIGHT...WEAK HIGH PRES WILL MOVE ACROSS THE REGION
DURING THE DAY. WILL PROBABLY SEE SOME BREAKS IN THE CLOUDS...
THOUGH NEXT SYSTEM QUICKLY WORKING E SO ANY BREAKS WILL BE SHORT
LIVED. WINDS WILL VEER AROUND TO S AND START TO PICK UP ESPECIALLY
FRI NIGHT AS PRECIP APPROACHES. TEMPS WILL HIT THEIR LOWS EARLY
FRI NIGHT...THEN WILL RISE THROUGH THE NIGHT AS PRECIP MOVES IN.
TEMPS MAY BE COLD ENOUGH FOR PRECIP TO START AS MIXED SLEET OR
FREEZING RAIN. HOWEVER...AS S WINDS INCREASES...MILDER AIR WILL
WORK IN AND MOST AREAS SHOULD CHANGE OVER TO RAIN BEFORE SUNRISE.
SATURDAY...MODELS STILL IN VERY GOOD AGREEMENT IN SWINGING A COLD
FRONT TOWARD THE REGION AS ITS ASSOCIATED STRONG LOW PRES MOVES
ACROSS EASTERN ONTARIO AND CENTRAL QUEBEC. VERY STRONG H925 JET
WORKS ACROSS INTO EASTERN MA/RI BY AROUND MIDDAY THROUGH THE
AFTERNOON...UPWARDS TO 65-70 KT. WILL LIKELY SEE WIND GUSTS
INCREASE QUICKLY WITH GUSTS UP TO 25-35 KT...HIGHEST ALONG THE S
COAST AND ISLANDS. SOME OF THE MOS GUIDANCE STARTING TO SHOW MILD
TEMPS ALONG WITH 2M MODEL TEMPS...SO USED THESE FOR MAX READINGS
OF THE LOWER-MID 50S FOR MOST AREAS.
ALSO NOTING GOOD AREA OF INSTABILITY WORKING IN AHEAD OF THE
FRONT...WITH LIFTED INDICES FROM ZERO TO -2...K INDICES IN THE
LOWER 30S AND TOTAL TOTALS IN THE LOWER 50S...AGAIN ACROSS EASTERN
AREAS. HAVE MENTIONED CHANCE OF TSTMS FOR THE LATE MORNING AND
AFTERNOON ACROSS THESE AREAS. WILL NEED TO MONITOR FOR STRONG
GUSTS THAT MAY MIX DOWN WITH ANY CONVECTION.
SATURDAY NIGHT THROUGH MONDAY NIGHT...LOW CONFIDENCE. THE SHOWERS
SHOULD HAVE PRETTY MUCH EXITED THE SOUTHEAST NEW ENGLAND COAST BY
EARLY SAT EVENING...AS THE COLD FRONT WORKS THROUGH THE REGION.
HOWEVER...WE ARE GOING TO HAVE TO WATCH A COUPLE WAVES OF LOW
PRESSURE THAT FORM ON THE FRONT...WHICH WILL BE HUNG UP OFF THE
ATLANTIC COAST. THE LATEST GFS/ECMWF KEEP BOTH WAVES OF
LOW PRESSURE FAR ENOUGH SOUTHEAST OF THE REGION TO KEEP MOST OF THE
PRECIPITATION OFF THE SOUTHEAST NEW ENGLAND COAST. HOWEVER...A FEW
OF THE GFS ENSEMBLES AND THE LATEST GGEM SHOW THE POTENTIAL FOR A
TRACK CLOSER TO THE COAST. LOW CONFIDENCE AT THIS TIME...BUT DID
INCLUDE SOME LOW POPS TO COVER THIS POTENTIAL. IF PRECIPITATION
DOES MAKE IT FAR ENOUGH WEST...IT MAY BE COLD ENOUGH TO SUPPORT SOME
WINTRY PRECIPITATION. ITS A LOW PROBABILITY AT THIS POINT...BUT
CERTAINLY WILL NEED TO BE WATCHED.
TUESDAY AND WEDNESDAY...MODERATE TO HIGH CONFIDENCE.
IT SHOULD START OFF QUITE COLD TUE MORNING WITH HIGH PRESSURE
OVERHEAD. HOWEVER...TEMPERATURES SHOULD MODERATE SIGNIFICANTLY BY
WED AS THE HIGH MOVES OFF THE COAST WITH A RETURN SOUTHWEST FLOW OF
AIR. EXPECT DRY WEATHER OVER THIS PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
THURSDAY NIGHT...MODERATE CONFIDENCE. LEFTOVER PERIODS OF MVFR-IFR
CIGS/VSBYS MAINLY ACROSS EASTERN MA/RI/S NH. MVFR VSBYS MAY LINGER
AFTER MIDNIGHT ALONG E COAST...OTHERWISE MAINLY VFR CONDITIONS
AFTER MIDNIGHT.
FRIDAY...MODERATE CONFIDENCE. MAINLY VFR CONDITIONS THROUGH THE
DAY...THEN WILL LIKELY SEE MVFR CIGS/VSBYS MOVE IN FROM W-E MAINLY
AROUND OR AFTER MIDNIGHT IN MAINLY RAIN...THOUGH MIXED FZRA/PL
ACROSS INLAND AREAS AT THE ONSET. PATCHY FOG DEVELOPING LATE.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PATCHY FOG EARLY. PRECIP CHANGING OVER TO SNOW SAT
NIGHT BUT WILL TAPER OFF FROM W-E. S WIND GUSTS WILL LIKELY REACH
25-35 KT ACROSS E MA/RI...HIGHEST ACROSS S COAST AND THE ISLANDS.
SATURDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. PROBABLY VFR
THE MAJORITY OF THE TIME...BUT A PERIOD OR TWO OF MVFR CONDITIONS
ARE POSSIBLE.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 17 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
THURSDAY NIGHT...WINDS WILL BACK FROM NE TO N AND SLOWLY DIMINISH.
SEAS WILL ALSO SLOWLY SUBSIDE...BUT REMAIN WELL ABOVE 5 FT ON MOST
OF THE WATERS...HIGHEST ON THE EASTERN OUTER WATERS.
FRIDAY...NE WINDS GUSTING UP TO 30 KT EARLY WILL DIMINISH DURING
THE AFTERNOON...THEN VEER TO SE-S FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS WILL REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...STRONG LOW LEVEL JET WILL MOVE ACROSS THE WATERS AHEAD
OF APPROACHING COLD FRONT. EXPECT S-SW WINDS TO GUSTING UP TO GALE
FORCE OVER THE OPEN WATERS SAT AFTERNOON. SEAS WILL BUILD UP TO
10-12 FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SATURDAY NIGHT THROUGH MONDAY...MAY SEE LEFTOVER GALE FORCE GUSTS
EARLY SAT NIGHT ON THE EASTERN OUTER WATERS. OTHERWISE...ENOUGH
COLD AIR ADVECTION SHOULD RESULT IN SCA NORTHWEST WIND GUSTS AND
SEAS ACROSS THE OUTER WATERS FOR A GOOD PORTION OF THE PERIOD.
THERE COULD BE A PERIOD WHERE THE WINDS TURN MORE NORTH NORTHEAST
IF AN OCEAN STORM TRACKS CLOSE ENOUGH TO THE COAST.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING UNTIL 3 AM EST THURSDAY FOR ANZ256.
&&
$$
SYNOPSIS...KJC/FRANK
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...FRANK/EVT
AVIATION...KJC/FRANK/EVT
MARINE...KJC/FRANK/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
401 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING WELL WEST OF THE
REGION WILL RESULT IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY...FOLLOWED BY CHILLIER WEATHER EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON
SATURDAY WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT
MORNING.
* CHILLY TEMPS FOLLOW SUN THROUGH TUE
* MODERATING TEMPS BY WED
DETAILS...
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE
SYSTEM ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID
MORNING. THIS SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS
SOUTHERN NEW ENGLAND. BECAUSE OF THE STRENGTH OF THIS
SYSTEM...PRESSURE GRADIENT IS EXTREMELY TIGHT AND EXPECT WINDY
CONDITIONS AREA WIDE EARLY SATURDAY MORNING THROUGH THE EVENING
HOURS. TEMPERATURES WILL START OUT BELOW FREEZING ESP ACROSS
NORTHERN MASS AND SOUTHERN NEW HAMPSHIRE. AS PRECIP MOVES IN...A MIX
PRECIPITATION WILL OCCUR DURING THE MORNING HOURS. STILL TO MUCH
UNCERTAINTY RIGHT NOW TO PUT AMOUNTS OR EXACT LOCATION WITH THE
RAIN/MIX PRECIP LINE WILL SET UP AS WELL AS TIMING OF THE SWITCHOVER
TO ALL RAIN. SINCE THIS SYSTEM IS DEPENDING AS IT APPROACHES THE
AREA...STRONG WAA WILL MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO
8-10C. THEREFORE EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK
AS TEMPS WILL REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE
TO STRONG SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT
OUT OF THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE
GFS...AND WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT
THUNDER SO HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS
SATURDAY COULD GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE
DAY...MIXED PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS
THE SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY
TUNE AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
SATURDAY NIGHT THROUGH MONDAY NIGHT...LOW CONFIDENCE.
THE SHOWERS SHOULD HAVE PRETTY MUCH EXITED THE SOUTHEAST NEW ENGLAND
COAST BY EARLY SAT EVENING...AS THE COLD FRONT WORKS THROUGH THE
REGION.
HOWEVER...WE ARE GOING TO HAVE TO WATCH A COUPLE WAVES OF LOW
PRESSURE THAT FORM ON THE FRONT...WHICH WILL BE HUNG UP OFF THE
ATLANTIC COAST. THE LATEST GFS/ECMWF KEEP BOTH WAVES OF
LOW PRESSURE FAR ENOUGH SOUTHEAST OF THE REGION TO KEEP MOST OF THE
PRECIPITATION OFF THE SOUTHEAST NEW ENGLAND COAST. HOWEVER...A FEW
OF THE GFS ENSEMBLES AND THE LATEST GGEM SHOW THE POTENTIAL FOR A
TRACK CLOSER TO THE COAST. LOW CONFIDENCE AT THIS TIME...BUT DID
INCLUDE SOME LOW POPS TO COVER THIS POTENTIAL. IF PRECIPITATION
DOES MAKE IT FAR ENOUGH WEST...IT MAY BE COLD ENOUGH TO SUPPORT SOME
WINTRY PRECIPITATION. ITS A LOW PROBABILITY AT THIS POINT...BUT
CERTAINLY WILL NEED TO BE WATCHED.
TUESDAY AND WEDNESDAY...MODERATE TO HIGH CONFIDENCE.
IT SHOULD START OFF QUITE COLD TUE MORNING WITH HIGH PRESSURE
OVERHEAD. HOWEVER...TEMPERATURES SHOULD MODERATE SIGNIFICANTLY BY
WED AS THE HIGH MOVES OFF THE COAST WITH A RETURN SOUTHWEST FLOW OF
AIR. EXPECT DRY WEATHER OVER THIS PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SATURDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. PROBABLY VFR
THE MAJORITY OF THE TIME...BUT A PERIOD OR TWO OF MVFR CONDITIONS
ARE POSSIBLE.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 15 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SATURDAY NIGHT THROUGH MONDAY...
ENOUGH COLD AIR ADVECTION SHOULD RESULT IN SCA NORTHWEST WIND GUSTS
AND SEAS ACROSS THE OUTER-WATERS FOR A GOOD PORTION OF THE PERIOD.
THERE COULD BE A PERIOD WHERE THE WINDS TURN MORE NORTH NORTHEAST IF
AN OCEAN STORM TRACKS CLOSE ENOUGH TO THE COAST.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING FROM 7 PM THIS EVENING TO 3 AM EST THURSDAY FOR
ANZ256.
&&
$$
SYNOPSIS...KJC/FRANK
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...DUNTEN/FRANK
AVIATION...KJC/FRANK
MARINE...KJC/FRANK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
349 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING WELL WEST OF THE
REGION WILL RESULT IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY...FOLLOWED BY DRY CONDITIONS INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURRS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* ACCUMULATING SNOW AND MIXED PRECIP WILL LAST INTO INTO THU NIGHT
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON SATURDAY
WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT MORNING.
CONFIDENCE...
INCREASING CONFIDENCE ON THE SYSTEM MOVING THROUGH ON THURSDAY.
HIGH CONFIDENCE THAT ACCUMULATING SNOW...INCLUDING WARNING
CRITERIA WILL OCCUR ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. FOR THE SATURDAY SYSTEM...HIGH CONFIDENCE THAT PRECIP
WILL OCCUR...MODERATE CONFIDENCE ON TIMING AND PRECIP TYPE.
MODELS...
OVERALL MODEL TRENDS LINE UP WITH THIS SYSTEM WHICH HELPS INCREASE
FORECASTERS CONFIDENCE. DECIDED TO LEAN TOWARDS THE NAM/ECMWF RATHER
THAN THE GFS AS IT DOES NOT HANDLE COLD AIR DAMMING ALL TO WELL.
ALSO THE NAM/ECMWF HAVE BEEN HANDING THIS SYSTEM THE PAST FEW RUNS
WELL AND HAS A GOOD TRACK RECORD FOR SYSTEM THIS MONTH. WHILE THE
NAM IS STILL COLDER IN THE VERTICAL PROFILE BLENDING THE ECMWF AND
CANADIAN WILL HELP CORRECT ANY BIAS THAT THE NAM HAS. FOR QPF DID A
BLEND WITH THE SREF/NAM/ECMWF/GFS. ALL MODELS HAVE SIMILAR OUTPUTS
WITH A FEW BEING MORE THAN OTHERS...SO TRENDED TOWARDS AN AVERAGE.
ONE CONCERN IS THE POTENTIAL FOR MESOSCALE BANDING...HAVE TRIED TO
INCORPORATE THAT INTO THE GRIDS. SURFACE TEMPS WHERE TRENDED TO THE
NAM/PREV FORECAST AS MODELS HAVE BEEN COMING IN COOLER THAN THERE
12Z RUNS. OVERALL GENERAL MODEL AGREEMENT WITH THIS SYSTEM.
DETAILS...
COASTAL LOW WILL DEVELOP ACROSS LONG ISLAND MOVE SOUTH OF ACK DURING
THIS TIME FRAME. THIS LOW WILL KEEP PRECIP GOING ACROSS THE AREA
THROUGH THE DAY AND INTO THE OVERNIGHT HOURS. THIS LOW WILL DEEPEN
AS IT MOVES THROUGH AND CAUSE ENHANCEMENT OVER THE REGION...ALONG
AND NORTH OF THE TURNPIKE. RAIN/SNOW LINE WILL CONTINUE TO MOVE
NORTHWARD AS TEMPS INCREASE ACROSS RI/NORTHERN CT AND THE CAPE AS
THICKNESSES MOVES NORTHWARD. ONCE THING TO NOTE IS THE SURFACE
TROUGHING ACROSS THE 95-CORRIDOR. BELIEVE THIS IS WHERE THE COASTAL
FRONT WILL SET UP AS WARM AIR ACROSS THE WATERS WILL MEET THE COLD
AIR OVER THE LAND...WHICH WILL LEAD TO SOME TRICKY AMOUNTS ACROSS
THE COASTAL REGIONS. WHERE THE COASTAL FRONT SETS UP...AND AS
INDICATED BY THE NAM...GOOD MOISTURE TRANSPORT MOVING ACROSS THE
FRONTAL REGION...COULD SEE HIGHER AMOUNTS. BELIEVE THE HIGHEST
AMOUNTS WILL BE NORTH OF THE I-90 CORRIDOR AS THERE WILL BE SOME
ENHANCEMENT FROM THE COASTAL LOW AS IT IS A SLOWER MOVER. SNOW WILL
BEGIN TO TAPER OFF FROM WEST TO EAST BY THE EVENING AND LAST INTO
THE OVERNIGHT HOURS.
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE SYSTEM
ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID MORNING. THIS
SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS SOUTHERN NEW
ENGLAND. BECAUSE OF THE STRENGTH OF THIS SYSTEM...PRESSURE GRADIENT
IS EXTREMELY TIGHT AND EXPECT WINDY CONDITIONS AREA WIDE EARLY
SATURDAY MORNING THROUGH THE EVENING HOURS. TEMPERATURES WILL START
OUT BELOW FREEZING ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. AS PRECIP MOVES IN...A MIX PRECIPITATION WILL OCCUR
DURING THE MORNING HOURS. STILL TO MUCH UNCERTAINTY RIGHT NOW TO
PUT AMOUNTS OR EXACT LOCATION WITH THE RAIN/MIX PRECIP LINE WILL SET
UP AS WELL AS TIMING OF THE SWITCHOVER TO ALL RAIN. SINCE THIS
SYSTEM IS DEPENDING AS IT APPROACHES THE AREA...STRONG WAA WILL
MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO 8-10C. THEREFORE
EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK AS TEMPS WILL
REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE TO STRONG
SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT OUT OF
THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE GFS...AND
WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT THUNDER SO
HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS SATURDAY COULD
GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE DAY...MIXED
PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY TUNE
AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
EXTENDED: SUNDAY-TUESDAY...MODERATE CONFIDENCE.
MODELS SEEM TO BE IN SOME AGREEMENT FOR THE EXTENDED WITH A UPPER
LEVEL DISTURBANCE MOVING THROUGH SUNDAY NIGHT INTO MONDAY. HIGH
PRESSURE WILL DOMINATE MONDAY NIGHT THROUGH TUESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SUNDAY...MODERATE CONFIDENCE. MVFR CIGS/VSBYS POSSIBLE DURING THE
MORNING ACROSS RI/SE MA...OTHERWISE MAINLY VFR.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 15 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...E-NE WINDS WILL INCREASE...REACHING GALE FORCE AS A
GALE WARNING IS OUT FOR THE EASTERN WATERS. CONDITIONS WILL THEN
DIMINISH TO SMALL CRAFT CRITERIA THROUGH THU NIGHT. SEAS WILL BUILD
UP TO 15 FEET ON THE EASTERN OPEN WATERS AS WELL.
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SUNDAY...WINDS VEER TO W...BUT GUSTS FORECASTED TO REACH SMALL CRAFT
CRITERIA. SEAS REMAIN AOA 5 FT ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING FROM 7 PM THIS EVENING TO 3 AM EST THURSDAY FOR
ANZ256.
&&
$$
SYNOPSIS...KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...DUNTEN
AVIATION...KJC/DUNTEN
MARINE...KJC/DUNTEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
119 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION WEDNESDAY AFTERNOON INTO THURSDAY. FAST MOVING HIGH
PRESSURE WILL BRING DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING
WELL WEST OF THE REGION WILL RESULT IN RAINY AND MILD WEATHER WITH
BLUSTERY WINDS SATURDAY...FOLLOWED BY DRY CONDITIONS INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1 PM UPDATE...
SNOW IS RACING INTO SNE EARLY THIS AFTERNOON AND WILL REACH CAPE
COD DURING THE NEXT HOUR. THE PRECIP MAY BEGIN AS A BRIEF PERIOD
OF RAIN ON THE CAPE BUT QUICKLY CHANGE TO SNOW. MOSTLY RAIN
EXPECTED OVER THE ISLANDS WHERE TEMPS IN THE 40S AND DEWPOINTS
CLOSE TO 30. BASED ON LATEST RADAR TRENDS A PERIOD OF MOD/HVY
SNOW IS LIKELY AND RUC SUPPORTS THIS WITH A DECENT SLUG OF QPF
THROUGH 00Z. WE HAVE INCREASED SNOW AMOUNTS THIS AFTERNOON ACROSS
CENTRAL AND W MA...N CT INTO NW RI WHERE 2-4" POSSIBLE BY
EVENING. 1-2" EXPECTED IN THE COASTAL PLAIN ALTHOUGH ACCUMULATION
HERE MAY BE CONFINED TO THE COLDER SURFACES AND GRASSY AREAS AS
TEMPS HOVER AORUND 33. IT STILL APPEARS DRY SLOT WILL BE MOVING
INTO REGION TOWARD 00Z AS THIS INITIAL SHOT OF WAA PRECIP MOVES
OUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WARMER AIR STARTS TO MOVE OVER SOUTHERN NEW ENGLAND CHANGING THE
SNOW TO MORE OF A WINTRY MIX...MAINLY SOUTH OF I-90 IN MA...CT AND
RI. RAIN SHOULD BE THE DOMINANT TYPE ACROSS CAPE COD AND THE
ISLANDS. WHILE LIGHTER IN INTENSITY...STILL EXPECTING ACCUMULATING
SNOW AND SLEET FOR MOST OF THE REGION.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* ACCUMULATING SNOW AND MIXED PRECIP WILL LAST INTO INTO THU NIGHT
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON SATURDAY
WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT MORNING.
CONFIDENCE...
INCREASING CONFIDENCE ON THE SYSTEM MOVING THROUGH ON THURSDAY.
HIGH CONFIDENCE THAT ACCUMULATING SNOW...INCLUDING WARNING
CRITERIA WILL OCCUR ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. FOR THE SATURDAY SYSTEM...HIGH CONFIDENCE THAT PRECIP
WILL OCCUR...MODERATE CONFIDENCE ON TIMING AND PRECIP TYPE.
THURSDAY...MODERATE CONFIDENCE.
THIS WAS THE MAIN FOCUS FOR THIS FORECAST PACKAGE AS THERE ARE STILL
SOME DETAILS THAT NEED TO BE IRONED OUT FOR THIS UPCOMING SYSTEM.
GENERALLY...A THIRD AREA OF PRECIP WILL MOVE ACROSS THE FORECAST
AREA THURSDAY MORNING AS THE SECONDARY LOW DEVELOPS SOUTH OF
NANTUCKET. THIS LOW WILL SLOWLY MOVE EASTWARD THROUGH THE DAY
THURSDAY AND FINALLY EJECT OVER THE ATLANTIC WATERS BY LATE THURSDAY
AS UPPER LEVEL DISTURBANCE PUSHES IT OUT. THIS SYSTEM WILL BRING A
MIX BAG OF PRECIP ACROSS THE AREA CAUSING FOR A MESSY MORNING
COMMUTE ON THURSDAY.
MODELS...
OVERALL MODEL TRENDS LINE UP WITH THIS SYSTEM WHICH HELPS INCREASE
FORECASTERS CONFIDENCE. DECIDED TO LEAN TOWARDS THE NAM/ECMWF RATHER
THAN THE GFS AS IT DOES NOT HANDLE COLD AIR DAMMING ALL TO WELL.
ALSO THE NAM/ECMWF HAVE BEEN HANDING THIS SYSTEM THE PAST FEW RUNS
WELL AND HAS A GOOD TRACK RECORD FOR SYSTEM THIS MONTH. WHILE THE
NAM IS STILL COLDER IN THE VERTICAL PROFILE BLENDING THE ECMWF AND
CANADIAN WILL HELP CORRECT ANY BIAS THAT THE NAM HAS. FOR QPF DID A
BLEND WITH THE SREF/NAM/ECMWF/GFS. ALL MODELS HAVE SIMILAR OUTPUTS
WITH A FEW BEING MORE THAN OTHERS...SO TRENDED TOWARDS AN AVERAGE.
ONE CONCERN IS THE POTENTIAL FOR MESOSCALE BANDING...HAVE TRIED TO
INCORPORATE THAT INTO THE GRIDS. SURFACE TEMPS WHERE TRENDED TO THE
NAM/PREV FORECAST AS MODELS HAVE BEEN COMING IN COOLER THAN THERE
12Z RUNS. OVERALL GENERAL MODEL AGREEMENT WITH THIS SYSTEM.
DETAILS...
COASTAL LOW WILL DEVELOP ACROSS LONG ISLAND MOVE SOUTH OF ACK DURING
THIS TIME FRAME. THIS LOW WILL KEEP PRECIP GOING ACROSS THE AREA
THROUGH THE DAY AND INTO THE OVERNIGHT HOURS. THIS LOW WILL DEEPEN
AS IT MOVES THROUGH AND CAUSE ENHANCEMENT OVER THE REGION...ALONG
AND NORTH OF THE TURNPIKE. RAIN/SNOW LINE WILL CONTINUE TO MOVE
NORTHWARD AS TEMPS INCREASE ACROSS RI/NORTHERN CT AND THE CAPE AS
THICKNESSES MOVES NORTHWARD. ONCE THING TO NOTE IS THE SURFACE
TROUGHING ACROSS THE 95-CORRIDOR. BELIEVE THIS IS WHERE THE COASTAL
FRONT WILL SET UP AS WARM AIR ACROSS THE WATERS WILL MEET THE COLD
AIR OVER THE LAND...WHICH WILL LEAD TO SOME TRICKY AMOUNTS ACROSS
THE COASTAL REGIONS. WHERE THE COASTAL FRONT SETS UP...AND AS
INDICATED BY THE NAM...GOOD MOISTURE TRANSPORT MOVING ACROSS THE
FRONTAL REGION...COULD SEE HIGHER AMOUNTS. BELIEVE THE HIGHEST
AMOUNTS WILL BE NORTH OF THE I-90 CORRIDOR AS THERE WILL BE SOME
ENHANCEMENT FROM THE COASTAL LOW AS IT IS A SLOWER MOVER. SNOW WILL
BEGIN TO TAPER OFF FROM WEST TO EAST BY THE EVENING AND LAST INTO
THE OVERNIGHT HOURS.
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE SYSTEM
ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID MORNING. THIS
SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS SOUTHERN NEW
ENGLAND. BECAUSE OF THE STRENGTH OF THIS SYSTEM...PRESSURE GRADIENT
IS EXTREMELY TIGHT AND EXPECT WINDY CONDITIONS AREA WIDE EARLY
SATURDAY MORNING THROUGH THE EVENING HOURS. TEMPERATURES WILL START
OUT BELOW FREEZING ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. AS PRECIP MOVES IN...A MIX PRECIPITATION WILL OCCUR
DURING THE MORNING HOURS. STILL TO MUCH UNCERTAINTY RIGHT NOW TO
PUT AMOUNTS OR EXACT LOCATION WITH THE RAIN/MIX PRECIP LINE WILL SET
UP AS WELL AS TIMING OF THE SWITCHOVER TO ALL RAIN. SINCE THIS
SYSTEM IS DEPENDING AS IT APPROACHES THE AREA...STRONG WAA WILL
MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO 8-10C. THEREFORE
EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK AS TEMPS WILL
REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE TO STRONG
SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT OUT OF
THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE GFS...AND
WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT THUNDER SO
HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS SATURDAY COULD
GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE DAY...MIXED
PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY TUNE
AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
EXTENDED: SUNDAY-TUESDAY...MODERATE CONFIDENCE.
MODELS SEEM TO BE IN SOME AGREEMENT FOR THE EXTENDED WITH A UPPER
LEVEL DISTURBANCE MOVING THROUGH SUNDAY NIGHT INTO MONDAY. HIGH
PRESSURE WILL DOMINATE MONDAY NIGHT THROUGH TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN NEAR THE SOUTH COAST. DRY
SLOT MAY RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT
ANOTHER PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY
WIND GUSTS TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SUNDAY...MODERATE CONFIDENCE. MVFR CIGS/VSBYS POSSIBLE DURING THE
MORNING ACROSS RI/SE MA...OTHERWISE MAINLY VFR.
&&
.MARINE...
LIGHT WINDS THROUGH THIS MORNING...THEN EASTERLY WINDS WILL
INCREASE LATER TODAY AND ESPECIALLY TONIGHT AS A LOW-LEVEL JET
MOVES NORTH ACROSS THE WATERS. WIND GUSTS UP TO 40 KT ARE POSSIBLE
TONIGHT...ESPECIALLY ACROSS THE EASTERN COASTAL WATERS.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...E-NE WINDS WILL INCREASE...REACHING GALE FORCE AS A
GALE WARNING IS OUT FOR THE EASTERN WATERS. CONDITIONS WILL THEN
DIMINISH TO SMALL CRAFT CRITERIA THROUGH THU NIGHT. SEAS WILL BUILD
UP TO 15 FEET ON THE EASTERN OPEN WATERS AS WELL.
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SUNDAY...WINDS VEER TO W...BUT GUSTS FORECASTED TO REACH SMALL CRAFT
CRITERIA. SEAS REMAIN AOA 5 FT ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>006-
008>010-012-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ007-
013>016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 3 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ233>237-256.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 7 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
&&
$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...KJC
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...KJC/DUNTEN
MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
112 PM EST WED FEB 29 2012
.PREV DISCUSSION...
UPDATE...
/ISSUED 1141 AM EST WED FEB 29 2012/
CURRENT SATELLITE ANALYSIS SHOWS CLOUDS STARTING TO BREAK UP IN
CENTRAL GEORGIA. TEMPS WERE LOWER THAN FORECAST FOR THE SOUTHEAST
PART OF THE CWA SO DECIDED TO LOWER THE HIGH BY A FEW DEGREES DOWN
THERE. THE FORECAST DEWPOINTS WERE LOWER THAN WHAT WAS
OBSERVED...SO POPULATED THE DEWPOINT GRIDS WITH THE 12Z RUC THAT
SEEMED TO HAVE A BETTER HANDLE ON THE DEWPOINTS.
WITH THE UPGRADE TO A MODERATE RISK OF SEVERE WEATHER OVER
NORTHERN GEORGIA CHANGED GRIDS TO REPRESENT THIS UPGRADE. DECIDED
TO INCLUDE THE SEVERE WORDING FOR MOST OF THE NORTHERN PART OF THE
CWA. RIGHT NOW IT LOOKS LIKE THE BEST CHANCE OF TORNADOES WILL BE
DURING THE EVENING HOURS. AS THE COLD FRONT PUSHES SOUTH INTO THE
STATE...EXPECT THE STORMS TO TRANSITION INTO A LINE AND DAMAGING
WINDS WOULD THEN BECOME THE MAIN THREAT.
ARG
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED 347 AM EST WED FEB 29 2012/
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE GREAT LAKES STATES...DOWN THE MS RIVER VALLEY...ACROSS TX/MX
AND OUT INTO THE PACIFIC. THE PARENT LOW CENTER IS SPINNING AND
DEEPENING ALONG THE NE/IA/SD BORDERS. THIS LOW CENTER IS EXPECTED
TO MOVE NE OVER THE NEXT 36 HOURS BECOMING CENTERED OVER THE NEW
ENGLAND STATES BY 12-18Z THU. ITS TRAILING COLD FRONT WILL ALSO
CONTINUE MOVING EAST...PUSHING INTO NW GA BY 00-06Z THU. WITH THE
WARM FRONT WELL NORTH GA WE WILL BE IN THE WARM SECTOR OF THIS
SYSTEM PRETTY MUCH ALL DAY TODAY. WITH DEWPOINTS IN THE UPPER 50S
AND LOWER 60S ACROSS THE REGION AND TEMPS EXPECTED IN THE 70S
TODAY...BOTH THE GFS AND ECMWF KEEP PRECIP ACROSS THE AREA ALL DAY
TODAY. THE LOCAL WRF MODEL KEEPS PRECIP CONFINED NEAR THE COLD
FRONT AND DOES NOT BRING ANY DECENT SHOWERS OR THUNDERSTORMS INTO
THE STATE UNTIL AFTER 00Z THU. HAVE COMPROMISED BETWEEN THE
3...WILL KEEP PRECIP ACROSS NORTH GA ALL DAY AND MOVE IT SLOWLY
SOUTHWARD THROUGH TONIGHT. INSTABILITIES INDICES INCREASE AFTER
00Z THU WITH THE FRONTAL PASSAGE ALSO. MUCAPES GET INTO THE
300-500 J/KG RANGE WITH 0-6KM BULK SHEAR AROUND 60-70 KT. THERE IS
ALSO A 45-55KT LOW LEVEL JET ASSOCIATED WITH THE FRONTAL PASSAGE.
WILL CONTINUE TO MENTION THUNDER TODAY AS THIS ENVIRONMENT WILL
SUPPORT ROTATING UPDRAFTS...AND AN ISOLATED SEVERE STORM/TORNADO
OR TWO. SPC HAS PUT THE NORTHERN HALF OF THE STATE UNDER A SLIGHT
RISK AREA. THE SYSTEM BEGINS TO LOOSE STRENGTH AFTER 06Z THU AS
THE FRONT CONTINUES TO PUSH SOUTH THROUGH THE AREA. POPS AND
THUNDER CHANCES DIMINISH THROUGH THE DAY THURSDAY BEFORE THE NEXT
SYSTEM FRI INTO SAT. TEMPS WILL REMAIN 10-12 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
LONG TERM /FRIDAY THROUGH TUESDAY/...
THE COLD FRONT MENTIONED ABOVE STALL ACROSS CENTRAL/SOUTH GA THU
BEFORE GETTING PULLED BACK NORTH AS A WARM FRONT THU NIGHT AS NEXT
LOW CENTER DEVELOPS. A CLOSED LOW CENTER DEVELOPS OVER OK FRI
MORNING AND LIFTS NE INTO THE GREAT LAKES STATES AS IT DEEPENS
THROUGH SAT MORNING. THIS LOW CENTER PULLS THE FIRST COLD FRONT
NORTHWARD AS A WARM FRONT FRIDAY WITH A SECOND COLD FRONT PUSHING
INTO OUR AREA SAT MORNING. THIS PATTERN WILL PUT GA IN THE WARM
MOIST SECTOR AGAIN DURING THE PRIME HEATING OF THE DAY FRI.
INSTABILITY INDICES PEAK FRI AFTERNOON WITH MUCAPES AROUND 300-500
J/KG AND 0-6KM BULK SHEAR IN THE 50-60 KT RANGE. THIS IS BEGINNING
TO LOOK LIKE IT WILL BE A REPEAT OF WHAT IS EXPECTED TODAY. THIS IS
WHY SPC HAS PUT NW GA UNDER A SLIGHT RISK FOR FRI. WILL DEFINITELY
SEE SOME THUNDERSTORMS FRI JUST NOT SURE ON THE INTENSITY OF THE
STORMS JUST YET. THE FRONT SWEEPS THROUGH THE STATE SAT MORNING WITH
A LARGE HIGH PRESSURE RIDGE BUILDING IN FROM TX SAT AFTERNOON. THIS
RIDGE SETS UP OVER GA AND KEEPS THE AREA DRY THROUGH THE MIDDLE OF
NEXT WEEK. TEMPS FINALLY GET DOWN TO NEAR SEASONAL NORMS DAYS 4-7.
&&
.AVIATION...
18Z UPDATE...
BULK OF PRECIP SHOULD HOLD OFF UNTIL TONIGHT...HOWEVER THERE IS A
CHANCE FOR SOME PRECIP LATE THIS AFTERNOON...MAINLY AT THE
NORTHERN SITES. GIVEN LOW CHANCES THOUGH...AM NOT ADVERTISING IN
THE TAF EXCEPT FOR CB. DID PUSH BACK TIMING OF TSRA IN TAFS. SOME
BREAKS ON VSBY SATELLITE ACROSS EASTERN ALABAMA SO BETWEEN THIS
AND LIFTING CIGS...MVFR CIGS SHOULD BECOME VFR LATER THIS
AFTERNOON. CLOUDS WILL BUILD BACK IN TONIGHT AS FRONT APPROACHES.
WINDS WILL REMAIN SW AND BECOME W TO NW TOMORROW.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WINDS AND VSBYS. MEDIUM CONFIDENCE ON CIGS. LOW
CONFIDENCE ON TIMING OF PRECIP.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 55 76 56 / 20 70 60 50
ATLANTA 72 57 73 61 / 30 70 50 50
BLAIRSVILLE 66 48 70 48 / 70 100 10 50
CARTERSVILLE 73 52 74 54 / 50 80 40 50
COLUMBUS 76 63 77 63 / 20 50 30 40
GAINESVILLE 67 53 73 56 / 40 80 50 50
MACON 74 63 78 61 / 10 50 30 40
ROME 74 53 76 54 / 70 80 10 50
PEACHTREE CITY 73 57 74 58 / 20 60 50 50
VIDALIA 76 63 79 63 / 10 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1141 AM EST WED FEB 29 2012
.UPDATE...
CURRENT SATELLITE ANALYSIS SHOWS CLOUDS STARTING TO BREAK UP IN
CENTRAL GEORGIA. TEMPS WERE LOWER THAN FORECAST FOR THE SOUTHEAST
PART OF THE CWA SO DECIDED TO LOWER THE HIGH BY A FEW DEGREES DOWN
THERE. THE FORECAST DEWPOINTS WERE LOWER THAN WHAT WAS
OBSERVED...SO POPULATED THE DEWPOINT GRIDS WITH THE 12Z RUC THAT
SEEMED TO HAVE A BETTER HANDLE ON THE DEWPOINTS.
WITH THE UPGRADE TO A MODERATE RISK OF SEVERE WEATHER OVER
NORTHERN GEORGIA CHANGED GRIDS TO REPRESENT THIS UPGRADE. DECIDED
TO INCLUDE THE SEVERE WORDING FOR MOST OF THE NORTHERN PART OF THE
CWA. RIGHT NOW IT LOOKS LIKE THE BEST CHANCE OF TORNADOES WILL BE
DURING THE EVENING HOURS. AS THE COLD FRONT PUSHES SOUTH INTO THE
STATE,,,EXPECT THE STORMS TO TRANSITION INTO A LINE AND DAMAGING
WINDS WOULD THEN BECOME THE MAIN THREAT.
&&
ARG
.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED 347 AM EST WED FEB 29 2012/
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE GREAT LAKES STATES...DOWN THE MS RIVER VALLEY...ACROSS TX/MX
AND OUT INTO THE PACIFIC. THE PARENT LOW CENTER IS SPINNING AND
DEEPENING ALONG THE NE/IA/SD BORDERS. THIS LOW CENTER IS EXPECTED
TO MOVE NE OVER THE NEXT 36 HOURS BECOMING CENTERED OVER THE NEW
ENGLAND STATES BY 12-18Z THU. ITS TRAILING COLD FRONT WILL ALSO
CONTINUE MOVING EAST...PUSHING INTO NW GA BY 00-06Z THU. WITH THE
WARM FRONT WELL NORTH GA WE WILL BE IN THE WARM SECTOR OF THIS
SYSTEM PRETTY MUCH ALL DAY TODAY. WITH DEWPOINTS IN THE UPPER 50S
AND LOWER 60S ACROSS THE REGION AND TEMPS EXPECTED IN THE 70S
TODAY...BOTH THE GFS AND ECMWF KEEP PRECIP ACROSS THE AREA ALL DAY
TODAY. THE LOCAL WRF MODEL KEEPS PRECIP CONFINED NEAR THE COLD
FRONT AND DOES NOT BRING ANY DECENT SHOWERS OR THUNDERSTORMS INTO
THE STATE UNTIL AFTER 00Z THU. HAVE COMPROMISED BETWEEN THE
3...WILL KEEP PRECIP ACROSS NORTH GA ALL DAY AND MOVE IT SLOWLY
SOUTHWARD THROUGH TONIGHT. INSTABILITIES INDICES INCREASE AFTER
00Z THU WITH THE FRONTAL PASSAGE ALSO. MUCAPES GET INTO THE
300-500 J/KG RANGE WITH 0-6KM BULK SHEAR AROUND 60-70 KT. THERE IS
ALSO A 45-55KT LOW LEVEL JET ASSOCIATED WITH THE FRONTAL PASSAGE.
WILL CONTINUE TO MENTION THUNDER TODAY AS THIS ENVIRONMENT WILL
SUPPORT ROTATING UPDRAFTS...AND AN ISOLATED SEVERE STORM/TORNADO
OR TWO. SPC HAS PUT THE NORTHERN HALF OF THE STATE UNDER A SLIGHT
RISK AREA. THE SYSTEM BEGINS TO LOOSE STRENGTH AFTER 06Z THU AS
THE FRONT CONTINUES TO PUSH SOUTH THROUGH THE AREA. POPS AND
THUNDER CHANCES DIMINISH THROUGH THE DAY THURSDAY BEFORE THE NEXT
SYSTEM FRI INTO SAT. TEMPS WILL REMAIN 10-12 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE COLD FRONT MENTIONED ABOVE STALL ACROSS CENTRAL/SOUTH GA THU
BEFORE GETTING PULLED BACK NORTH AS A WARM FRONT THU NIGHT AS NEXT
LOW CENTER DEVELOPS. A CLOSED LOW CENTER DEVELOPS OVER OK FRI
MORNING AND LIFTS NE INTO THE GREAT LAKES STATES AS IT DEEPENS
THROUGH SAT MORNING. THIS LOW CENTER PULLS THE FIRST COLD FRONT
NORTHWARD AS A WARM FRONT FRIDAY WITH A SECOND COLD FRONT PUSHING
INTO OUR AREA SAT MORNING. THIS PATTERN WILL PUT GA IN THE WARM
MOIST SECTOR AGAIN DURING THE PRIME HEATING OF THE DAY FRI.
INSTABILITY INDICES PEAK FRI AFTERNOON WITH MUCAPES AROUND 300-500
J/KG AND 0-6KM BULK SHEAR IN THE 50-60 KT RANGE. THIS IS BEGINNING
TO LOOK LIKE IT WILL BE A REPEAT OF WHAT IS EXPECTED TODAY. THIS IS
WHY SPC HAS PUT NW GA UNDER A SLIGHT RISK FOR FRI. WILL DEFINITELY
SEE SOME THUNDERSTORMS FRI JUST NOT SURE ON THE INTENSITY OF THE
STORMS JUST YET. THE FRONT SWEEPS THROUGH THE STATE SAT MORNING WITH
A LARGE HIGH PRESSURE RIDGE BUILDING IN FROM TX SAT AFTERNOON. THIS
RIDGE SETS UP OVER GA AND KEEPS THE AREA DRY THROUGH THE MIDDLE OF
NEXT WEEK. TEMPS FINALLY GET DOWN TO NEAR SEASONAL NORMS DAYS 4-7.
&&
.AVIATION...
12Z UPDATE...
/ISSUED 703 AM EST WED FEB 29 2012/ MVFR TO CONTINUE FOR THE
BETTER PART OF THE MORNING. SOME DIFFICULTIES IN TIMING OF
CLEARING/LIFTING IN THE AFTERNOON...IN THAT GUIDANCE IS NOT
CONSISTENT WITH DOING THAT ACROSS THE AREA. SPLIT THE DIFFERENCE
AND CLEARED ATL OUT BRIEFLY IN THE AFTERNOON...BUT CONFIDENCE IS
LOW. WINDS WILL BE WESTERLY FOR THE DURATION OF THE PERIOD...WITH
GUSTS UP TO 20KTS AT MAX HEATING. TSRA NOT EXPECTED TO IMPACT
AIRPORTS UNTIL AFTER 21Z.
//ATL CONFIDENCE...
12Z UPDATE...
LOW ON TIMING OF CIGS LIFTING. MEDIUM ON REMAINING ELEMENTS.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 55 76 56 / 20 70 30 50
ATLANTA 72 57 73 61 / 30 70 30 50
BLAIRSVILLE 66 48 70 48 / 70 90 10 50
CARTERSVILLE 73 52 74 54 / 50 80 20 50
COLUMBUS 76 63 77 63 / 20 50 20 40
GAINESVILLE 67 53 73 56 / 40 80 30 50
MACON 77 63 78 61 / 10 50 20 40
ROME 74 53 76 54 / 70 80 10 50
PEACHTREE CITY 73 57 74 58 / 20 60 30 50
VIDALIA 80 63 79 63 / 10 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
354 PM EST WED FEB 29 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
SURFACE AND UPPER LEVEL LOW WILL PUSH THROUGH THE GREAT LAKES
OVERNIGHT...WITH SOME ADDITIONAL CLOUDINESS POSSIBLE OVERNIGHT.
GUSTY WINDS ASSOCIATED WITH THE SYSTEM WILL SUBSIDE OVERNIGHT.
HIGH PRESSURE WILL RETURN QUIET WEATHER TO THE AREA THROUGH
FRIDAY...WHEN ANOTHER LOW PRESSURE SYSTEM PUSHES INTO THE AREA
FRIDAY AND FRIDAY NIGHT...BRINGING THE POTENTIAL FOR THUNDERSTORMS
AND PERHAPS SEVERE WEATHER TO THE AREA.
THE REMAINDER OF THE FORECAST PERIOD WILL GENERALLY BE
QUIET...WITH HIGH PRESSURE IN PLACE.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
FOCUS IS ON WINDS THIS AFTERNOON AND SKY COVER/TEMPS OVERNIGHT.
GUIDANCE IS SIMILAR AND A BLEND IS USED.
HAVE TRIMMED WIND ADVISORY BACK TO JUST THE NORTHWEST CORNER OF
THE FORECAST AREA...AS STRONGER GUSTS HAVE NOT MATERIALIZED ACROSS
MUCH OF THE AREA. HOWEVER...STRONGER GUSTS ARE OCCURRING IN THE
NORTHWEST...AND 40 PLUS KNOT GUSTS ARE OCCURRING JUST TO OUR
NORTHWEST. RUC SOUNDINGS INDICATE THE POTENTIAL FOR THESE TO MAKE
THE NORTHWEST FORECAST AREA LATE THIS AFTERNOON BEFORE GUSTS
SUBSIDE THIS EVENING.
CLOUD COVER ASSOCIATED WITH UPPER LOW WILL BRUSH OUR NORTHERN
THIRD OR SO OF THE FORECAST AREA OVERNIGHT...BUT SOUTHERN PORTIONS
WILL REMAIN CLEAR.
SOME WEAK ISENTROPIC LIFT WILL SKIRT THE NORTHERN PORTIONS OF THE
FORECAST AREA THIS EVENING...AND MAY SEE A COUPLE OF SPRINKLES OR
A BIT OF DRIZZLE...BUT THIS IS RATHER UNCERTAIN SO CHOSE TO
EXCLUDE A MENTION AT THIS TIME.
ON TEMPS...FEEL THAT MOS IS A BIT TOO COOL...ESPECIALLY GIVEN THAT
CONDITIONS WILL GENERALLY REMAIN SOMEWHAT BREEZY OVERNIGHT AND
CLOUD COVER WILL ALSO CONTRIBUTE TO KEEPING THINGS A BIT WARMER
IN SPOTS. HAVE RAISED CONSENSUS A COUPLE OF DEGREES...AND THIS IS
WELL IN LINE WITH UPSTREAM MINS FROM LAST NIGHT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON POTENTIAL FOR THUNDERSTORMS FRIDAY AND FRIDAY
NIGHT...AS WELL AS POSSIBLE SEVERE WEATHER. SIGNIFICANT GUIDANCE
DISCREPANCIES NOTED IN THE STRENGTH AND POSITION OF SYSTEM PUSHING
INTO THE AREA DURING THIS TIME...AND HAVE TEMPERED EXPECTATIONS
TOWARD THE CONSENSUS WHILE NOT COMPLETELY DISCOUNTING THE
SIGNIFICANTLY STRONGER NAM.
HIGH PRESSURE WILL KEEP CONDITIONS DRY THROUGH TOMORROW NIGHT.
ANOTHER LOW PRESSURE SYSTEM APPROACHES FOR FRIDAY AND FRIDAY
NIGHT...AND THIS IS WHERE GUIDANCE DIVERGES. MUCH OF THE AVAILABLE
GUIDANCE LEANS TOWARD A BIT WEAKER AND FURTHER SOUTH
SOLUTION...SIMILAR TO LAST NIGHT AND TODAY...WITH THE COLD FRONT
THROUGH MUCH EARLIER IN THE DAY. NAM IS SIGNIFICANTLY STRONGER AND
MORE WOUND UP WITH THE LOW...AND IF THIS VERIFIES...A SIGNIFICANT
SEVERE WEATHER THREAT WILL BE POSSIBLE ACROSS MUCH OF THE
AREA...WITH ANY AND ALL THREATS POSSIBLE...AS SREF POSTPROCESSED
GUIDANCE INDICATES SIGNIFICANT LOW AND DEEP LAYER SHEAR AND WEAK
TO MODERATE INSTABILITY. OVERALL SHOWERS AND THUNDERSTORMS LOOK TO
BE A GOOD BET FRIDAY AFTERNOON AND EVENING...AND THE SEVERE THREAT
BEARS CLOSE SCRUTINY AS THE DAY APPROACHES.
ON TEMPS...GUIDANCE APPEARS TOO COOL THROUGHOUT...AND HAVE
ADJUSTED CONSENSUS UP MOST PERIODS. DEPENDING ON TIME OF WARM
FRONT ARRIVAL LATE THURSDAY NIGHT OR EARLY FRIDAY...A NON DIURNAL
TEMPERATURE PROGRESSION MAY BE NECESSARY THURSDAY NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
PER THE EMSEMBLES THE EXTENDED PERIOD FOR THE MOST PART SHOULD BE
DRY...WITH A FEW EXCEPTIONS. A SHORTWAVE EMBEDDED IN THE UPPER TROF
PUSHING ACROSS THE SRN GREAT LAKES WILL BRING SOME PRECIP CHANCES TO
THE AREA ON SUNDAY...POSSIBLY MIXING WITH SOME LIGHT SNOW WELL NORTH
OF I-70 AS TEMPS APPEARS COOL ENOUGH. AFTER THAT A RIDGE BUILDS
INTHROUGH THE EARLY PORTION OF THE WEEK AND THEN A VERY STRONG FRONT
WILL APPROACH FROM THE WEST ON TUESDAY...BRINGING WHAT LOOKS LIKE A
GOOD CHANCE FOR SHOWERS TO THE REGION ON WED.
&&
.AVIATION /DISCUSSION FOR THE 29/2100Z TAF UPDATE/...
UPDATE...
NO CHANGES
PREVIOUS DISCUSSION...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>038-043>045-051-052.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
312 PM EST WED FEB 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 29/2100Z TAF UPDATE/...
UPDATE...
NO CHANGES
PREVIOUS DISCUSSION...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1143 AM EST WED FEB 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 291800Z TAFS/...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
124 PM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN BODY OF RAIN ASSOCIATED WITH THE WARM FRONT HAS PUSHED
EAST OF THE DISTRICT. ADDITIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED TO FORM THIS AFTERNOON AHEAD OF THE
APPROACHING COLD FRONT. SOME OF THESE STORMS WILL CONTAIN HEAVY
DOWNPOURS ESPECIALLY IN THE SOUTHERN PORTIONS OF THE WARNING AREA.
A FLASH FLOOD WATCH HAS BEEN ISSUED FOR WEST VIRGINIA SOUTH OF THE
MASON DIXON LINE UNTIL 11PM. AN ADDITIONAL INCH OF RAIN IN THREE HOURS
OR LESS WILL BRING STREAMS AND CREEKS OUT OF THEIR BANKS.
THE SURFACE LAYER WILL BECOME WELL MIXED, THIS AFTERNOON AS CLOUDS BEGIN
TO BREAK. SCATTERED SHOWERS AND THUNDERSTORMS CAN GENERATE GUSTY
SURFACE WINDS. MOST OF EASTERN OHIO AND THE REMAINDER OF THE
FORECAST AREA FROM PITTSBURGH SOUTH REMAINS IN A SLIGHT RISK OF
SEVERE THUNDERSTORMS FOR THIS AFTERNOON INTO THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH UNTIL 11 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...NONE.
WV...FLASH FLOOD WATCH UNTIL 11 PM EST THIS EVENING FOR WVZ012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
115 PM EST WED FEB 29 2012
.SYNOPSIS...
ISSUED AT 700 AM EST WED FEB 29 2012
AFTER DROPPING A FEW INCHES OF SNOW AND SLEET ACROSS NORTHERN LOWER
MICHIGAN...LOW PRESSURE WILL MOVE EAST TODAY WITH ONLY SCATTERED
SHOWERS AND DRIZZLE THIS AFTERNOON. COLDER AIR WILL MOVE IN TONIGHT
WITH SOME SNOW SHOWERS. AFTER A BREAK IN THE ACTION...ANOTHER STORM
WILL MOVE IN ON FRIDAY WITH RAIN CHANGING TO SNOW LATE FRIDAY NIGHT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 113 PM EST WED FEB 29 2012
DROPPED ALL THE ADVISORY BEFORE NOON...AS THE PRECIPITATION WAS
SWEEPING OUT OF THE AREA. DRY SLOT HAS SPREAD ACROSS THE ENTIRE
AREA AS OF 100PM...WITH CLEARING SWEEPING IN FROM THE SOUTHWEST.
ELIMINATED MOST OF THE POPS FOR THE AFTERNOON HOURS...OUTSIDE OF
SOME DRIZZLE POSSIBLE UP ON THE HIGH GROUND OF CENTRAL LOWER AND
SHOWERS TRYING TO PUSH BACK IN WITH THE UPPER LOW TOWARD 00Z.
MAIN FOCUS NOW WILL BE ON HOW FAR NORTH THE CLEARING AND WARMTH COMES.
PUSHED 50S INTO THE I94 ROW OF COUNTIES AND PARTIAL CLEARING ALL
THE WAY TO I96. WILL NEED TO KEEP AN EYE ON THIS THOUGH IS IT MAY
MAKE A RUN FURTHER NORTH INTO THE FORECAST AREAS. MODEL PROGS HOLD
CLOUDS IN FOR AREAS NORTH OF A MKG TO LAN LINE. GIVEN CURRENT
TRENDS ITS HARD NOT TO ENVISION THE CLEARING WORKING NORTH OF THAT
LINE...BUT AM GOING TO GIVE THE FORECAST A CHANCE AT THIS POINT
AND WILL UPDATE AS NECESSARY. WINDS IN THE CLEAR SLOT ARE A
CONCERN AS WELL WITH GUSTS ABOVE 30 KNOTS. LATEST RUC HAS THE
TRIPLE POINT AND WARM NOSE SLIDING ALONG I94...SO WILL LET THE
CURRENT FORECAST HOLD.
PREVIOUS DISCUSSION FOLLOWS...
THE ENTIRE AREA WILL SEE THICKER CLOUDS THEN MOVE IN LATE THIS
AFTERNOON AND EVENING AS THE WRAP AROUND MOISTURE AND COLD AIR
WITH THE MAIN LOW ROTATES ACROSS THE AREA. WE WILL SEE SHOWERS
ASSOCIATED WITH THE UPPER LOW ALSO MOVE IN. THE AIR WILL REMAIN
SUFFICIENTLY WARM ENOUGH UNTIL AROUND 03Z THAT ALL SHOWERS WILL
REMAIN RAIN. THAT WILL TRANSITION OVER TO SNOW FROM W TO E AFTER
03Z. WE COULD SEE A LIGHT ACCUMULATION OF SNOW...ESPECIALLY UP
NORTH CLOSER TO THE LOW AND ACROSS THE HIGHER TERRAIN UP NORTH.
THIS PCPN SHOULD MOVE OUT LATE WED NIGHT. SOME RESIDUAL FORCING
MAY BE LEFT IN THE LOWER ATMOSPHERE AS THE MID AND UPPER LEVEL
MOISTURE MOVES OUT. THIS COULD SET UP THE AREA FOR A CHC OF SOME
LIGHT DRIZZLE OR FREEZING DRIZZLE FOR A SHORT TIME TOWARD DAYBREAK
ON THU. THAT WILL MOVE OUT BY MID MORNING...AND ALLOW FOR A QUIET
DAY AS HIGH PRESSURE MOVES THROUGH THE AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 AM EST WED FEB 29 2012
MAIN EVENT IN THE EXTENDED IS A DEEPENING LOW MOVING ACROSS THE LP
OF MICHIGAN ON FRIDAY. 00Z RUNS OF ECMWF AND GFS ARE IN EXCELLENT
AGREEMENT WITH THE TRACK AND STRENGTH OF THE LOW. LOOKS LIKE RAIN
FRIDAY CHANGING TO SNOW FRIDAY NIGHT WITH ONLY LIGHT ACCUMS IN THE
LAKE ENHANCED WRAP AROUND SNOW.
TWEAKED TEMPS DOWN A BIT OVER THE WEEKEND AS MODELS IN GOOD
AGREEMENT ON MINUS 10 TO 15C AT 850 MB MOVING SATURDAY AND SUNDAY.
MODELS ALSO IN GOOD AGREEMENT ON A CLIPPER MOVING THROUGH
SATURDAY NIGHT INTO SUNDAY...SO WENT ALONG WITH APX AND IWX IN
BUMPING UP POPS FOR SUNDAY. COULD BE SOME ACCUMS WITH THE CLIPPER
AND LAKE ENHANCEMENT IN WEST FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 113 PM EST WED FEB 29 2012
DIFFICULT SET OF TAF FORECASTS AT 18Z...WITH A CLEAR SLOT TRYING
TO MOVE ACROSS THE AREA. ALL SITES ARE LOCKED INTO IFR/LIFR AT
18Z...WITH CLEAR AND VFR NOT FAR OFF ON THE HORIZON. CLEARING HAS
PUSHED THROUGH BEH AND SBN AT 18Z...WITH BIV AND AZO NOT FAR
BEHIND. TRIED TO WORK THE CLEARING ACROSS THE I94 TAF SITES OF
AZO...BTL AND JXN THROUGH THE AFTERNOON...BUT THE NORTHERN SITES
WERE A TOUGHER CALL. THINK MKG WILL CLEAR FOR A WHILE AS
WELL...BUT HELD ON TO BROKEN IFR CLOUDS FOR GRR AND LAN.
CONFIDENCE IS LOW IN THIS THOUGH AND WILL NEED TO BE WATCHED AS
THE CLEARING IS SURGING NORTHEAST. THE COLDER GROUND AND LOW
SLIDING EAST MAY TRY TO KEEP THE CLOUDS IN AT GRR AND LAN WHICH IS
HOW THE FORECAST WAS WRITTEN.
WILL NEED TO KEEP A CLOSE EYE ON THE WINDS SWEEPING IN FROM THE
SOUTHWEST AS WELL AS GUSTS TO 35 KNOTS OR SO ARE OCCURRING BENEATH
THE CLEAR SKIES.
TONIGHT SNOW SHOWERS WILL SWEEP BACK IN WITH MVFR CEILINGS. THE
MVFR CONDITIONS SHOULD PERSIST THROUGH THE MORNING ON THURSDAY.
&&
.MARINE...
ISSUED AT 413 AM EST WED FEB 29 2012
WE WILL HOLD ON TO THE GALE WARNING FOR ALL OF THE NEARSHORE AREA.
WINDS AT THE COASTAL SITES APPEAR TO NOT BE REACHING GALE
CRITERIA. CRITERIA IS LIKELY BEING MET OFFSHORE DUE TO THE ERLY
FLOW. WINDS WILL DIMINISH SOME TODAY AS A FRONT MOVES THROUGH THE
AREA. WINDS WILL PICK UP ONCE AGAIN BEHIND THE FRONT LATE TODAY.
GALES WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF TONIGHT
BEFORE DIMINISHING.
&&
.HYDROLOGY...
ISSUED AT 413 AM EST WED FEB 29 2012
RIVERS ALL REMAIN WITHIN THEIR BANKS THIS MORNING WITH NO FLOOD
HEADLINES OUT FOR NOW. RAINFALL/LIQUID EQUIVALENT SHOULD END UP
WITH UP TO HALF AN INCH. SOME CONTINGENCY FORECASTS BY THE RFC
INDICATE WE COULD START SEEING SOME RIVER POINTS GO ABOVE
ACTION/ADVISORY STAGE. THIS SEEMS MORE LIKELY TO OCCUR AFTER THE
NEXT SYSTEM MOVES THROUGH ON FRIDAY WITH MORE RAINFALL LOOKING
LIKELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 1 AM EST THURSDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ/DUKE
LONG TERM....OSTUNO
AVIATION...DUKE
MARINE...NJJ
HYDROLOGY...NJJ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
548 PM EST WED FEB 29 2012
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS EXIT THE AREA AS A COLD FRONT PUSHES
THROUGH OVERNIGHT BRINGING COOLER AND DRIER AIR FOR TONIGHT AND
THURSDAY. HIGH PRESSURE WILL BUILD INTO THE AREA FOR
THURSDAY...WITH ANOTHER LOW PRESSURE SYSTEM WILL BRING THE
LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE ONLY CONVECTION REMAINING IN AREA IS JUST SOUTH OF FCST AREA.
STILL SOME THREAT FOR TSTMS FOR SOUTHEAST...WITH STORMS FAST
MOVING AND OVERALL MOVEMENT TAKING THEM OUT OF AREA BY 01Z. CLEARING
WORKING THROUGH AREA...WITH WRAP AROUND CLOUDS ASSOC WITH THE UPR
LOW TO SKIRT ACROSS THE NORTH. TIGHTER PRESS GRADIENT ACROSS THE
NORTH WILL KEEP WIND GUSTS UP THROUGH PART OF THE OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE RISING NORTH FROM THE LOWER MS VALLEY WILL PUSH
PRETTY QUICKLY THROUGH AREA ON THURS. ANOTHER VIGOROUS S/WV WILL
DEVELOP OVER THE MID MS VALLEY AND PUSH TOWARD THE LWR GREAT LAKES
ON FRIDAY. SOME TIMING DIFFERENCES BETWEEN THE SLIGHTLY QUICKER
GFS/ECMWF AND THE MORE ENHANCED/SLOWER NAM. AM STICKING WITH A
BLEND OF THE GFS/ECMWF TIMING SOLUTION...WITH PRECIP BEGINNING
NEAR/AFTER NOON ON FRI. STRONG WAA AHEAD OF THE FRONT WILL BRING
ABOVE NORMAL TEMPS ON FRIDAY...WITH MID TO UPR 60S POSSIBLE. WIND
FIELDS MAINLY 18Z FRI-00Z SAT BRING 50-70+ KTS AT 925-950 HEIGHTS.
STORM MOTIONS SHOULD BE VERY MUCH LIKE TODAY WITH DAMAGING WINDS
POSSIBLE. THREAT LINGERS PAST 00Z...DIMINISHING BY 06Z WITH
APPROACHING FROPA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL BE DEPARTING THE AREA ON SATURDAY
MORNING...BRINGING AN END TO RAINFALL BY EARLY IN THE DAY. BEHIND
THE FRONT...COOL NORTHWESTERLY FLOW WILL SETTLE IN ACROSS THE
REGION. A PASSING SURFACE TROUGH WILL BRING IN A CHANCE OF
PRECIPITATION ON SUNDAY INTO SUNDAY NIGHT...WITH A LARGE UPPER
TROUGH CENTERED JUST EAST OF THE REGION AT THE SAME TIME. THIS WILL
BE A MIX OF RAIN AND SNOW...DEPENDING ON THE TIME OF DAY. THERE ARE
MODEL DIFFERENCES IN THE STRENGTH OF THIS TROUGH AND THE AMOUNT OF
MOISTURE IT WILL BE ABLE TO WORK WITH...WITH THE GFS DEPICTING A
DEEPER AND WETTER SOLUTION. THE HIGHER PRECIPITATION CHANCES WILL
LIKELY BE CLOSER TO THE UPPER SUPPORT...IN THE NORTHEASTERN PART OF
THE CWA.
MODELS ARE THEN IN GOOD AGREEMENT ON HIGH PRESSURE MOVING THROUGH
THE REGION AND SETTLING IN NEAR THE EAST COAST BY THE MIDDLE OF THE
WEEK. THIS WILL PUT THE CWA INTO A PERIOD OF DRY WEATHER AND
PROLONGED SOUTHERLY FLOW...WHICH SHOULD AGAIN BRING TEMPERATURES
WELL ABOVE NORMAL. AT THE SAME TIME...THE LONG WAVE PATTERN WILL
FAVOR RIDGING OVER THE EASTERN HALF OF THE US...WHICH HAS BEEN
FAIRLY STABLY RESOLVED BY MULTIPLE RUNS OF THE GFS/GFSE AS WELL AS
THE ECMWF. DIFFERENCES IN THE EVOLUTION OF THE TROUGHING OVER THE
WESTERN HALF OF THE COUNTRY SHOULD REMAIN MOSTLY IRRELEVANT TO THE
LOCAL FORECAST THROUGH AT LEAST TUESDAY NIGHT...WITH WEDNESDAY BEING
THE EARLIEST THAT A DISTURBANCE MIGHT PUSH EAST INTO THE OHIO VALLEY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR
SHORT TERM...JDR
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
403 PM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT PUSHING ACROSS THE AREA THROUGH THIS EVENING WILL
PUSH SHOWERS AND THUNDERSTORMS EAST OF THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD INTO THE AREA FOR THURSDAY...WITH ANOTHER
LOW PRESSURE SYSTEM WILL BRING THE LIKELIHOOD FOR SHOWERS AND
THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF CONVECTION PUSHING RAPIDLY THROUGH AREA. SEVERE THREAT IS
MARGINAL...WITH THE ONLY AREA OF SLIGHT THREAT BEING THE FAR
SOUTHEAST FCST AREA THROUGH ABOUT 22Z. CLEARING WORKING THROUGH
AREA...WITH WRAP AROUND CLOUDS ASSOC WITH THE UPR LOW TO SKIRT
ACROSS THE NORTH. TIGHTER PRESS GRADIENT ACROSS THE NORTH WILL
KEEP WIND GUSTS UP THROUGH PART OF THE OVERNIGHT.
TOR WATCH REMAINS UP IN THE EASTERN FCST AREA THROUGH 02Z...BUT
THREAT IS CONFINED AS MENTIONED ABOVE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE RISING NORTH FROM THE LOWER MS VALLEY WILL PUSH
PRETTY QUICKLY THROUGH AREA ON THURS. ANOTHER VIGOROUS S/WV WILL
DEVELOP OVER THE MID MS VALLEY AND PUSH TOWARD THE LWR GREAT LAKES
ON FRIDAY. SOME TIMING DIFFERENCES BETWEEN THE SLIGHTLY QUICKER
GFS/ECMWF AND THE MORE ENHANCED/SLOWER NAM. AM STICKING WITH A
BLEND OF THE GFS/ECMWF TIMING SOLUTION...WITH PRECIP BEGINNING
NEAR/AFTER NOON ON FRI. STRONG WAA AHEAD OF THE FRONT WILL BRING
ABOVE NORMAL TEMPS ON FRIDAY...WITH MID TO UPR 60S POSSIBLE. WIND
FIELDS MAINLY 18Z FRI-00Z SAT BRING 50-70+ KTS AT 925-950 HEIGHTS.
STORM MOTIONS SHOULD BE VERY MUCH LIKE TODAY WITH DAMAGING WINDS
POSSIBLE. THREAT LINGERS PAST 00Z...DIMINISHING BY 06Z WITH
APPROACHING FROPA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL BE DEPARTING THE AREA ON SATURDAY
MORNING...BRINGING AN END TO RAINFALL BY EARLY IN THE DAY. BEHIND
THE FRONT...COOL NORTHWESTERLY FLOW WILL SETTLE IN ACROSS THE
REGION. A PASSING SURFACE TROUGH WILL BRING IN A CHANCE OF
PRECIPITATION ON SUNDAY INTO SUNDAY NIGHT...WITH A LARGE UPPER
TROUGH CENTERED JUST EAST OF THE REGION AT THE SAME TIME. THIS WILL
BE A MIX OF RAIN AND SNOW...DEPENDING ON THE TIME OF DAY. THERE ARE
MODEL DIFFERENCES IN THE STRENGTH OF THIS TROUGH AND THE AMOUNT OF
MOISTURE IT WILL BE ABLE TO WORK WITH...WITH THE GFS DEPICTING A
DEEPER AND WETTER SOLUTION. THE HIGHER PRECIPITATION CHANCES WILL
LIKELY BE CLOSER TO THE UPPER SUPPORT...IN THE NORTHEASTERN PART OF
THE CWA.
MODELS ARE THEN IN GOOD AGREEMENT ON HIGH PRESSURE MOVING THROUGH
THE REGION AND SETTLING IN NEAR THE EAST COAST BY THE MIDDLE OF THE
WEEK. THIS WILL PUT THE CWA INTO A PERIOD OF DRY WEATHER AND
PROLONGED SOUTHERLY FLOW...WHICH SHOULD AGAIN BRING TEMPERATURES
WELL ABOVE NORMAL. AT THE SAME TIME...THE LONG WAVE PATTERN WILL
FAVOR RIDGING OVER THE EASTERN HALF OF THE US...WHICH HAS BEEN
FAIRLY STABLY RESOLVED BY MULTIPLE RUNS OF THE GFS/GFSE AS WELL AS
THE ECMWF. DIFFERENCES IN THE EVOLUTION OF THE TROUGHING OVER THE
WESTERN HALF OF THE COUNTRY SHOULD REMAIN MOSTLY IRRELEVANT TO THE
LOCAL FORECAST THROUGH AT LEAST TUESDAY NIGHT...WITH WEDNESDAY BEING
THE EARLIEST THAT A DISTURBANCE MIGHT PUSH EAST INTO THE OHIO VALLEY.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR
SHORT TERM...JDR
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
116 PM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT WORK ACROSS THE AREA THIS AFTERNOON AND
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MAINLY
SOUTHERN OHIO AND NORTHERN KENTUCKY. HIGH PRESSURE AND DRY AIR
WILL MOVE IN TONIGHT THROUGH THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL BRING THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIRD ROUND OF CONVECTION IS WORKING ACROSS THE SRN PORTION OF THE
FA ATTM. LATEST RUNS OF THE RUC AND HRRR ARE INDICATING THAT AS
THE CDFNT TO THE W WORKS E THIS AFTN...THAT ADDITIONAL CONVECTION
WILL AFFECT NRN KY INTO SRN OHIO. BACKED OFF THE THE PCPN ACROSS
THE N FOR THIS AFTN BASED ON THESE RUNS.
TOR WATCH REMAINS UP AFTER COORDINATION WITH SPC. THEY WANTED TO
LEAVE IT UP TO COVER THE POSSIBILITY OF REDEVELOPMENT LATE THIS
MORNING INTO AFTN.
KEPT HIGHS INTO THE MID TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A COLD FRONT WILL BE MOVING ACROSS THE AREA EARLY THIS
EVENING...WITH THUNDERSTORMS LIKELY AND DAMAGING WINDS POSSIBLE.
ACTIVITY WILL END BY LATE EVENING AS THE FRONT DEPARTS TO THE
EAST AND HIGH PRESSURE STARTS TO BUILD IN. THE HIGH WILL PROVIDE
DRY CONDITIONS AS IT MOVES ACROSS OHIO THURSDAY AND THURSDAY
NIGHT. THOUGH THERE WILL BE A BRIEF PERIOD OF COLD ADVECTION ON
THURSDAY...TEMPERATURES WILL STAY ABOVE NORMAL WITH HIGHS MAINLY IN
THE 50S.
ANOTHER LOW WILL DRAG A VIGOROUS COLD FRONT TO THE REGION ON
FRIDAY. WIND FIELDS ASSOCIATED WITH THE FAST MOVING COLD FRONT
SUGGEST STORM MOTIONS OF 50 KNOTS WHICH COULD YIELD DAMAGING WIND
GUSTS. STRONG WARM ADVECTION AHEAD OF THE COLD FRONT WILL CAUSE
TEMPERATURES TO BE WELL ABOVE NORMAL...WITH HIGHS REACHING THE
60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE AREA WILL THEN REMAIN UNDER NORTHWESTERLY UPPER LEVEL FLOW
OVER THE WEEKEND. THIS WILL BRING A COUPLE OF WEAK DISTURBANCES
ACROSS OUR AREA WITH CHANCES FOR RAIN/SNOW SHOWERS. TEMPERATURES
OVER THE WEEKEND WILL BE SEASONABLY COOL AS WE REMAIN UNDER THE
WESTERN EDGE OF A LARGE UPPER TROUGH. SURFACE HIGH PRESSURE WILL
BUILD ACROSS THE REGION BY LATE IN THE WEEKEND AND WILL SLOWLY
SLIDE EASTWARD INTO THE BEGINNING OF NEXT WEEK. THIS WILL PRODUCE
A WARMING TREND TO START OFF THE WEEK...WITH ABOVE NORMAL
TEMPERATURES EXPECTED BY MID WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...LATTO
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1138 AM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT WORK ACROSS THE AREA THIS AFTERNOON AND
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MAINLY
SOUTHERN OHIO AND NORTHERN KENTUCKY. HIGH PRESSURE AND DRY AIR
WILL MOVE IN TONIGHT THROUGH THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL BRING THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIRD ROUND OF CONVECTION IS WORKING ACROSS THE SRN PORTION OF THE
FA ATTM. LATEST RUNS OF THE RUC AND HRRR ARE INDICATING THAT AS
THE CDFNT TO THE W WORKS E THIS AFTN...THAT ADDITIONAL CONVECTION
WILL AFFECT NRN KY INTO SRN OHIO. BACKED OFF THE THE PCPN ACROSS
THE N FOR THIS AFTN BASED ON THESE RUNS.
TOR WATCH REMAINS UP AFTER COORDINATION WITH SPC. THEY WANTED TO
LEAVE IT UP TO COVER THE POSSIBILTY OF REDEVELOPEMENT LATE THIS
MORNING INTO AFTN.
KEPT HIGHS INTO THE MID TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A COLD FRONT WILL BE MOVING ACROSS THE AREA EARLY THIS
EVENING...WITH THUNDERSTORMS LIKELY AND DAMAGING WINDS POSSIBLE.
ACTIVITY WILL END BY LATE EVENING AS THE FRONT DEPARTS TO THE
EAST AND HIGH PRESSURE STARTS TO BUILD IN. THE HIGH WILL PROVIDE
DRY CONDITIONS AS IT MOVES ACROSS OHIO THURSDAY AND THURSDAY
NIGHT. THOUGH THERE WILL BE A BRIEF PERIOD OF COLD ADVECTION ON
THURSDAY...TEMPERATURES WILL STAY ABOVE NORMAL WITH HIGHS MAINLY IN
THE 50S.
ANOTHER LOW WILL DRAG A VIGOROUS COLD FRONT TO THE REGION ON
FRIDAY. WIND FIELDS ASSOCIATED WITH THE FAST MOVING COLD FRONT
SUGGEST STORM MOTIONS OF 50 KNOTS WHICH COULD YIELD DAMAGING WIND
GUSTS. STRONG WARM ADVECTION AHEAD OF THE COLD FRONT WILL CAUSE
TEMPERATURES TO BE WELL ABOVE NORMAL...WITH HIGHS REACHING THE
60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE AREA WILL THEN REMAIN UNDER NORTHWESTERLY UPPER LEVEL FLOW
OVER THE WEEKEND. THIS WILL BRING A COUPLE OF WEAK DISTURBANCES
ACROSS OUR AREA WITH CHANCES FOR RAIN/SNOW SHOWERS. TEMPERATURES
OVER THE WEEKEND WILL BE SEASONABLY COOL AS WE REMAIN UNDER THE
WESTERN EDGE OF A LARGE UPPER TROUGH. SURFACE HIGH PRESSURE WILL
BUILD ACROSS THE REGION BY LATE IN THE WEEKEND AND WILL SLOWLY
SLIDE EASTWARD INTO THE BEGINNING OF NEXT WEEK. THIS WILL PRODUCE
A WARMING TREND TO START OFF THE WEEK...WITH ABOVE NORMAL
TEMPERATURES EXPECTED BY MID WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WARM FRONT LIFTING NORTH INTO SRN OHIO ALONG WITH A STRONG
LOW LEVEL JET AND ELEVATED INSTBY HAS LED TO WIDESPREAD SHOWERS
AND EMBEDDED THUNDERSTORMS. CIGS HAVE DROPPED INTO THE MVFR CATEGORY
WITH OCCASIONAL IFR CIGS EXPECTED EARLY THIS MORNING.
THE WARM FRONT TO CONTINUE LIFTING NORTH THRU THE TAF SITES THIS
MORNING WITH ALL TAFS GETTING IN THE WARM SECTOR. THIS SHOULD
ALLOW FOR WIDESPREAD SHOWERS TO TAPER OFF THROUGH MID TO LATE
MORNING WITH SOME IMPROVEMENT IN CIGS LKLY. NUMERICAL MODELS CONTINUE
TO SHOW A NARROW BAND OF INSTBY NOSING UP INTO THE REGION DURG THE
LATE MORNING INTO THE AFTN...AHEAD OF AN APPROACHING COLD FRONT.
NAM SOLN CONTINUES TO BE MORE UNSTBL THAN GFS. HAVE A MENTION OF THUNDER
WITH MVFR CIGS AT ALL TAF SITES INTO MID AFTN.
WINDS WILL VEER TO THE SOUTHWEST THIS AFTN WITH GUSTS AS HIGH AS
28 KTS.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...LATTO
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
336 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND MOVES
OFF TO THE EAST THURSDAY MORNING. ANOTHER COLD FRONT IS EXPECTED TO
AFFECT THE CAROLINAS AND NORTHEAST GEORGIA FRIDAY INTO SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY AND LINGER INTO THE
EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 230 PM EST...LOW STRATUS AND PATCHY DRIZZLE STUBBORNLY HANGING ON
IN NE GA AND THER WESTERN UPSTATE IN THE WEAKLY CONVERGENT LOW
LEVEL FLOW. LIGHT RADAR RETURNS CONTINUE TO DEPICT THE DRIZZLE.
LATEST HRRR INDICATES THAT THIS SHOULD PERSIST FOR ANOTHER COUPLE
HOURS AND WILL CONTINUE TO INCLUDE IN THE WEATHER GRIDS. CLOUD BASES
STILL EXPECTED TO RISE LATE THIS AFTERNOON AS BETTER MIXING DEVELOPS.
12Z MODEL SOUNDINGS INDICATE THAT THE THREAT OF ANY CONVECTION
THIS AFTERNOON IS QUITE LOW DUE TO A CAP...SO HAVE LOWERED POPS FOR
LATE AFTERNOON PERIOD.
A POSSIBLE ROBUST SEVERE THREAT WILL EXIST TONIGHT AS A COLD FRONT
AND ATTENDENT CONVECTION MOVES ACROSS WESTERN CAROLINAS AND NE GA.
SPC HAS A MODERATE RISK EXTENDING INTO FAR WESTERN NC WITH A SLIGHT
RISK ELSEWHERE. LOOKS LIKE A DAMAGING WIND THREAT IS THE GREATEST
RISK...BUT HIGH HELICITIES SUPPORT AN ISOLATED TORNADO THREAT AS
WELL. LOOKS LIKE A BROKEN LINE OF THUNDERSTORMS...SOME POSSIBLY
SEVERE WILL MOVE THROUGH IN THE 00Z TO 06Z TIME FRAME. THE
CONVECTION ENTERING THE MOUNTAINS...WILL PROBABLY TEND TO WEAKEN AS
IT MOVES EASTWARD AS WINDS WILL HAVE A SOMEWHAT DWONSLOPING
COMPONENT...PLUS CAPES WILL BE DIURNALLY TRENDING DOWN AS WELL. WILL
HAVE TO WATCH FOR STRONG TO SEVERE CONVECTION MOVING OUT OF NORTHERN
AL/GA THAT COULD AFFECT THE PIEDMONT AREAS. CONVECTION/FRONT SHOULD
CLEAR THE FORECAST AREA AROUND 06Z WITH PARTIAL CLEARING COMMENCING
LATE TONIGHT.
THURSDAY IS SHAPING UP AS A VERY NICE DAY DAY AS THE FRONT LAYS OUT
TO THE SOUTH OF THE AREA AND HIGH PRESSURE BUILDS OVER THE AREA.
PLENTY SUNSHINE COUPLED WITH DOWNSLOPE FLOW WILL SEND TEMPS INTO THE
MID TO UPPER 70S OUTSIDE THE MOUTNAINS TO AROUND 70 MOUNTAIN
VALLEYS. ALTHOUGH IT WILL BE QUITE WARM...IT WILL NOT REACH RECORD
LEVELS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM WEDNESDAY...THE FIRST PART OF WEEKEND LOOKS ACTIVE. THE
OLD SURFACE FRONT TO OUR SOUTH WILL SPRING BACK TO LIFE THURSDAY
EVENING AS MOISTURE RETURNS FROM THE GULF AND VEERING WIND AT 850 MB
BRINGS RENEWED ISENTROPIC UPGLIDE ON THE 300K SURFACE. THE NEWLY
ACTIVITATED WARM FRONT SHOULD APPROACH FROM THE SOUTH WITH LIGHT
PRECIP BREAKING OUT FROM SOUTH TO NORTH IN THE PREDAWN HOURS...
PERHAPS ONLY WEST OF I-26 WHERE A CHANCE WILL BE CARRIED. THE
UPGLIDE AND WARM ADVECTION CONTINUES THROUGH FRIDAY AS THE WARM
FRONT LIFTS NORTHWARD...SO THE PRECIP CHANCES SPREAD ACROSS THE
REMAINDER OF THE FCST AREA...WITH A LIKELY POP ACROSS THE MTNS WHERE
THE MOST FAVORABLE UPSLOPE FLOW SHOULD BE. THIS FCST IS NOT WITHOUT
ITS POTENTIAL BUST WHERE TEMPS ARE CONCERNED. THE NAM HOLDS ONTO A
STRONGER PARENT HIGH OVER NEW ENGLAND...WHICH CONTRIBUTES TO A COLD
AIR DAMMING WEDGE E OF THE BLUE RIDGE...WHEREAS THE SURFACE HIGH ON
THE GFS IS MUCH WEAKER. AT THIS POINT...THE GFS LOOKS LIKE THE
BETTER CHOICE WITHOUT MUCH SEEN TO ANCHOR A HIGH TO OUR NE ON
FRIDAY. TEMPS WERE NUDGED A DEGREE OR TWO LOWER IN THE USUAL CAD
REGION TO HEDGE OUR BETS...BUT FOR THE MOST PART THE GFS IS
PREFERRED.
THE NEXT UPPER TROF WILL FEATURE AN ELONGATED AND POSTIVELY TILTED
SHORT WAVE ON SATURDAY THAT DIGS MUCH FARTHER S THAN TODAYS SYSTEM.
THE UPPER FORCING WILL GRADUALLY IMPROVE LATE FRIDAY NIGHT AND
SATURDAY MORNING IN ADVANCE OF A STRONG COLD FRONT. PRECIP CHANCES
ARE RAMPED BACK UP TO LIKELY ACROSS THE MTNS BEFORE SUNRISE. THERE
IS SOME UNCERTAINTY WITH THE TIMING OF THE FRONTAL PASSAGE...WHICH
IS MOST LIKELY SATURDAY DURING THE DAY. THE TREND HAS BEEN TO SLOW
THINGS DOWN BY A FEW HOURS. A CONTINUATION OF THIS TREND WILL BE THE
KEY TO DETERMINING OUR SEVERE WEATHER THREAT. THE MODELS MANAGE TO
DEVELOP STRONG MAINLY UNIDIRECTIONAL SHEAR ON SATURDAY AHEAD OF
FROPA...BUT LIMITED BUOYANCY BECAUSE OF THE TIMING. CAPE ON THE NAM
IS MEAGER AT BEST...AND MINIMAL ON THE GFS...FOR NOW. IF THE TIMING
SLIPS FURTHER...WE COULD HAVE A VERY INTERESTING SEVERE WEATHER
THREAT IN THE AFTERNOON EAST OF THE MTNS. PRECIP CHANCES WERE KEPT
TO LIKELY WITH FROPA OVER TIMING UNCERTAINTY...AND ENDED FROM THE
WEST LATE IN THE DAY. THERE IS SOME CARRYOVER INTO SATURDAY EVENING
BASED ON TIMING TREND...BUT THE FRONT SHOULD BE EAST OF THE REGION
BY MID EVENING AT THE LATEST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 PM WEDNESDAY...THE LATEST MEDIUM RANGE MODELS SUGGEST THAT
A COLD FRONT WILL MOVE OFF THE ATLANTIC COAST BY 12Z SUNDAY BEFORE A
WEAK UPPER SHORTWAVE SWINGS ACROSS THE NORTHERN PART OF OUR CWFA BY
SUNDAY AFTERNOON. THEREFORE...CLEARING SKIES CAN BE EXPECTED MAINLY
OVER THE LOWER PIEDMONT WHILE PORTIONS OF NC MOUNTAINS COULD SEE
INCREASING CLOUDINESS WITH LIGHT PRECIP DEVELOPING OVER THE AREA ON
SUNDAY AFTERNOON. PRECIPITATION WILL BE MAINLY LIQUID AS THE TEMPS
REMAIN ABOVE FREEZING IN THE AFTERNOON. AS THE SHORTWAVE MOVES OFF
TO THE EAST...A CANADIAN SURFACE HIGH WILL BUILD INTO THE REGION
LATE SUNDAY AND LINGER INTO EARLY PART OF NEXT WEEK. HENCE...MOSTLY
DRY CONDITIONS WITH MODERATING TEMPERATURES ARE EXPECTED SUNDAY
NIGHT THROUGH TUESDAY. WEDNESDAY...A MOIST SOUTHERLY FLOW WILL
INCREASE OVER OUR AREA IN ADVANCE OF APPROACHING COLD FRONT FROM THE
WEST. PRECIP WILL DEVELOP BY LATE WEDNESDAY IN RESPOND TO ISENTROPIC
LIFTING OVER THE REGION. HOWEVER...I HAVE LIMITED POPS TO SLIGHT
CHANCE LATE WED/THU DUE TO THE UNCERTAINTY. TEMPERATURES WILL REMAIN
3-5 DEGREES BELOW THE SEASONAL AVERAGES SUN/MON AND RISE ABOVE
NORMALS TUE/WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...IFR CONDITIONS CONTINUE AT MID-AFTERNOON. GUIDANCE
CONTINUE TO SUGGEST THAT CIGS WILL GRADUALLY INCREASE INTO THE MVFR
RANGE BY 20Z AND THEN ESSENTIALLY HOLD THERE. AN AREA OF DRIZZLE
ACROSS UPSTATE SC COULD PUT A WRENCH IN THIS THINKING AS VSBYS`S
HAVE CRASHED TO 2 MILES WITHIN IT WITH LIFR CIGS. HOWEVER...WILL BANK ON
IT DISSIPATING AS IT PROGRESSES E. AFTER 00Z...EXPECT A BROKEN LINE
OF THUNDERSTORMS TO APPROACH AND WILL CARRY A PERIOD OF TSRA IN THE
03Z-05Z TIMEFRAME. THE THREAT FOR A SEVERE STORM IS POSSIBLE...BUT
PROB TOO LOW AT THIS POINT TO PUT IN THE TAF. THE CONVECTION WILL
MOVE EAST OF THE AREA BY 06Z...WITH CONDITIONS IMPROVING TO VFR BY
09Z.
ELSEWHERE...PESKY LIFR STILL HANGING IN AT EARLY AFTERNOON. AREA OF
DRIZZLE OVER THE UPSTATE HAS LOWERED CIG/VSBY AT KGSP/KGMU AGAIN.
EXPECT THAT ONCE THIS MOVES EAST SOME RAPID IMPROVEMENT SHOULD
COMMENCE WITH CIGS IMPROVING TO MVFR AND VSBY TO VFR BY 21Z AS
MIXING IMPROVES. AT KAVL...GUIDANCE SUGGESTS THAT CURRENT VFR CONDITIONS
WILL FILL IN WITH MVFR BY 20Z OR SO. AFTER 00Z...A BROKEN LINE OF
THUNDERSTORMS WILL APPROACH FROM THE W-NW AND WILL CARRY A PERIOD OF
THUNDER AT ALL TAF SITES. A SEVERE STORMS ARE POSSIBLE...BUT PROB TOO
LOW TO PUT IN TAFS AT THE MOMENT. ONCE THE FRONT AND ASSOCIATION
CONVECTION MOVES EAST BY 05Z...EXPECT CONDITIONS TO IMPROVE TO VFR.
OUTLOOK...VFR/DRY WEATHER WILL CONTINUE INTO THU NIGHT. HOWEVER...BY
LATE THU NIGHT...MOISTURE WILL INCREASE YET AGAIN AS ANOTHER STORM
SYSTEM APPROACHES THE REGION FROM THE WEST. CHANCES FOR SHOWERS/FLT
RESTRICTIONS WILL PERSIST THROUGH AT LEAST SATURDAY MORNING. DRY
WEATHER SHOULD RETURN BY THE END OF THE WEEKEND.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...JOH
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
252 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND MOVES
OFF TO THE EAST THURSDAY MORNING. ANOTHER COLD FRONT IS EXPECTED TO
AFFECT THE CAROLINAS AND NORTHEAST GEORGIA FRIDAY INTO SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY AND LINGER INTO THE
EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 230 PM EST...LOW STRATUS AND PATCHY DRIZZLE STUBBORNLY HANGING ON
IN NE GA AND THER WESTERN UPSTATE IN THE WEAKLY CONVERGENT LOW
LEVEL FLOW. LIGHT RADAR RETURNS CONTINUE TO DEPICT THE DRIZZLE.
LATEST HRRR INDICATES THAT THIS SHOULD PERSIST FOR ANOTHER COUPLE
HOURS AND WILL CONTINUE TO INCLUDE IN THE WEATHER GRIDS. CLOUD BASES
STILL EXPECTED TO RISE LATE THIS AFTERNOON AS BETTER MIXING DEVELOPS.
12Z MODEL SOUNDINGS INDICATE THAT THE THREAT OF ANY CONVECTION
THIS AFTERNOON IS QUITE LOW DUE TO A CAP...SO HAVE LOWERED POPS FOR
LATE AFTERNOON PERIOD.
A POSSIBLE ROBUST SEVERE THREAT WILL EXIST TONIGHT AS A COLD FRONT
AND ATTENDENT CONVECTION MOVES ACROSS WESTERN CAROLINAS AND NE GA.
SPC HAS A MODERATE RISK EXTENDING INTO FAR WESTERN NC WITH A SLIGHT
RISK ELSEWHERE. LOOKS LIKE A DAMAGING WIND THREAT IS THE GREATEST
RISK...BUT HIGH HELICITIES SUPPORT AN ISOLATED TORNADO THREAT AS
WELL. LOOKS LIKE A BROKEN LINE OF THUNDERSTORMS...SOME POSSIBLY
SEVERE WILL MOVE THROUGH IN THE 00Z TO 06Z TIME FRAME. THE
CONVECTION ENTERING THE MOUNTAINS...WILL PROBABLY TEND TO WEAKEN AS
IT MOVES EASTWARD AS WINDS WILL HAVE A SOMEWHAT DWONSLOPING
COMPONENT...PLUS CAPES WILL BE DIURNALLY TRENDING DOWN AS WELL. WILL
HAVE TO WATCH FOR STRONG TO SEVERE CONVECTION MOVING OUT OF NORTHERN
AL/GA THAT COULD AFFECT THE PIEDMONT AREAS. CONVECTION/FRONT SHOULD
CLEAR THE FORECAST AREA AROUND 06Z WITH PARTIAL CLEARING COMMENCING
LATE TONIGHT.
THURSDAY IS SHAPING UP AS A VERY NICE DAY DAY AS THE FRONT LAYS OUT
TO THE SOUTH OF THE AREA AND HIGH PRESSURE BUILDS OVER THE AREA.
PLENTY SUNSHINE COUPLED WITH DOWNSLOPE FLOW WILL SEND TEMPS INTO THE
MID TO UPPER 70S OUTSIDE THE MOUTNAINS TO AROUND 70 MOUNTAIN
VALLEYS. ALTHOUGH IT WILL BE QUITE WARM...IT WILL NOT REACH RECORD
LEVELS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM WEDNESDAY...THE FIRST PART OF WEEKEND LOOKS ACTIVE. THE
OLD SURFACE FRONT TO OUR SOUTH WILL SPRING BACK TO LIFE THURSDAY
EVENING AS MOISTURE RETURNS FROM THE GULF AND VEERING WIND AT 850 MB
BRINGS RENEWED ISENTROPIC UPGLIDE ON THE 300K SURFACE. THE NEWLY
ACTIVITATED WARM FRONT SHOULD APPROACH FROM THE SOUTH WITH LIGHT
PRECIP BREAKING OUT FROM SOUTH TO NORTH IN THE PREDAWN HOURS...
PERHAPS ONLY WEST OF I-26 WHERE A CHANCE WILL BE CARRIED. THE
UPGLIDE AND WARM ADVECTION CONTINUES THROUGH FRIDAY AS THE WARM
FRONT LIFTS NORTHWARD...SO THE PRECIP CHANCES SPREAD ACROSS THE
REMAINDER OF THE FCST AREA...WITH A LIKELY POP ACROSS THE MTNS WHERE
THE MOST FAVORABLE UPSLOPE FLOW SHOULD BE. THIS FCST IS NOT WITHOUT
ITS POTENTIAL BUST WHERE TEMPS ARE CONCERNED. THE NAM HOLDS ONTO A
STRONGER PARENT HIGH OVER NEW ENGLAND...WHICH CONTRIBUTES TO A COLD
AIR DAMMING WEDGE E OF THE BLUE RIDGE...WHEREAS THE SURFACE HIGH ON
THE GFS IS MUCH WEAKER. AT THIS POINT...THE GFS LOOKS LIKE THE
BETTER CHOICE WITHOUT MUCH SEEN TO ANCHOR A HIGH TO OUR NE ON
FRIDAY. TEMPS WERE NUDGED A DEGREE OR TWO LOWER IN THE USUAL CAD
REGION TO HEDGE OUR BETS...BUT FOR THE MOST PART THE GFS IS
PREFERRED.
THE NEXT UPPER TROF WILL FEATURE AN ELONGATED AND POSTIVELY TILTED
SHORT WAVE ON SATURDAY THAT DIGS MUCH FARTHER S THAN TODAYS SYSTEM.
THE UPPER FORCING WILL GRADUALLY IMPROVE LATE FRIDAY NIGHT AND
SATURDAY MORNING IN ADVANCE OF A STRONG COLD FRONT. PRECIP CHANCES
ARE RAMPED BACK UP TO LIKELY ACROSS THE MTNS BEFORE SUNRISE. THERE
IS SOME UNCERTAINTY WITH THE TIMING OF THE FRONTAL PASSAGE...WHICH
IS MOST LIKELY SATURDAY DURING THE DAY. THE TREND HAS BEEN TO SLOW
THINGS DOWN BY A FEW HOURS. A CONTINUATION OF THIS TREND WILL BE THE
KEY TO DETERMINING OUR SEVERE WEATHER THREAT. THE MODELS MANAGE TO
DEVELOP STRONG MAINLY UNIDIRECTIONAL SHEAR ON SATURDAY AHEAD OF
FROPA...BUT LIMITED BUOYANCY BECAUSE OF THE TIMING. CAPE ON THE NAM
IS MEAGER AT BEST...AND MINIMAL ON THE GFS...FOR NOW. IF THE TIMING
SLIPS FURTHER...WE COULD HAVE A VERY INTERESTING SEVERE WEATHER
THREAT IN THE AFTERNOON EAST OF THE MTNS. PRECIP CHANCES WERE KEPT
TO LIKELY WITH FROPA OVER TIMING UNCERTAINTY...AND ENDED FROM THE
WEST LATE IN THE DAY. THERE IS SOME CARRYOVER INTO SATURDAY EVENING
BASED ON TIMING TREND...BUT THE FRONT SHOULD BE EAST OF THE REGION
BY MID EVENING AT THE LATEST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 PM WEDNESDAY...THE LATEST MEDIUM RANGE MODELS SUGGEST THAT
A COLD FRONT WILL MOVE OFF THE ATLANTIC COAST BY 12Z SUNDAY BEFORE A
WEAK UPPER SHORTWAVE SWINGS ACROSS THE NORTHERN PART OF OUR CWFA BY
SUNDAY AFTERNOON. THEREFORE...CLEARING SKIES CAN BE EXPECTED MAINLY
OVER THE LOWER PIEDMONT WHILE PORTIONS OF NC MOUNTAINS COULD SEE
INCREASING CLOUDINESS WITH LIGHT PRECIP DEVELOPING OVER THE AREA ON
SUNDAY AFTERNOON. PRECIPITATION WILL BE MAINLY LIQUID AS THE TEMPS
REMAIN ABOVE FREEZING IN THE AFTERNOON. AS THE SHORTWAVE MOVES OFF
TO THE EAST...A CANADIAN SURFACE HIGH WILL BUILD INTO THE REGION
LATE SUNDAY AND LINGER INTO EARLY PART OF NEXT WEEK. HENCE...MOSTLY
DRY CONDITIONS WITH MODERATING TEMPERATURES ARE EXPECTED SUNDAY
NIGHT THROUGH TUESDAY. WEDNESDAY...A MOIST SOUTHERLY FLOW WILL
INCREASE OVER OUR AREA IN ADVANCE OF APPROACHING COLD FRONT FROM THE
WEST. PRECIP WILL DEVELOP BY LATE WEDNESDAY IN RESPOND TO ISENTROPIC
LIFTING OVER THE REGION. SO I HAVE KEPT SLIGHT CHANCE POPS LATE
WED/THU. TEMPERATURES WILL REMAIN 5 -10 DEGREES BELOW NORMALS
SUN/MON BEFORE WARMING UP INTO NORMALS TUESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...IFR CONDITIONS CONTINUE AT MID-AFTERNOON. GUIDANCE
CONTINUE TO SUGGEST THAT CIGS WILL GRADUALLY INCREASE INTO THE MVFR
RANGE BY 20Z AND THEN ESSENTIALLY HOLD THERE. AN AREA OF DRIZZLE
ACROSS UPSTATE SC COULD PUT A WRENCH IN THIS THINKING AS VSBYS`S
HAVE CRASHED TO 2 MILES WITHIN IT WITH LIFR CIGS. HOWEVER...WILL BANK ON
IT DISSIPATING AS IT PROGRESSES E. AFTER 00Z...EXPECT A BROKEN LINE
OF THUNDERSTORMS TO APPROACH AND WILL CARRY A PERIOD OF TSRA IN THE
03Z-05Z TIMEFRAME. THE THREAT FOR A SEVERE STORM IS POSSIBLE...BUT
PROB TOO LOW AT THIS POINT TO PUT IN THE TAF. THE CONVECTION WILL
MOVE EAST OF THE AREA BY 06Z...WITH CONDITIONS IMPROVING TO VFR BY
09Z.
ELSEWHERE...PESKY LIFR STILL HANGING IN AT EARLY AFTERNOON. AREA OF
DRIZZLE OVER THE UPSTATE HAS LOWERED CIG/VSBY AT KGSP/KGMU AGAIN.
EXPECT THAT ONCE THIS MOVES EAST SOME RAPID IMPROVEMENT SHOULD
COMMENCE WITH CIGS IMPROVING TO MVFR AND VSBY TO VFR BY 21Z AS
MIXING IMPROVES. AT KAVL...GUIDANCE SUGGESTS THAT CURRENT VFR CONDITIONS
WILL FILL IN WITH MVFR BY 20Z OR SO. AFTER 00Z...A BROKEN LINE OF
THUNDERSTORMS WILL APPROACH FROM THE W-NW AND WILL CARRY A PERIOD OF
THUNDER AT ALL TAF SITES. A SEVERE STORMS ARE POSSIBLE...BUT PROB TOO
LOW TO PUT IN TAFS AT THE MOMENT. ONCE THE FRONT AND ASSOCIATION
CONVECTION MOVES EAST BY 05Z...EXPECT CONDITIONS TO IMPROVE TO VFR.
OUTLOOK...VFR/DRY WEATHER WILL CONTINUE INTO THU NIGHT. HOWEVER...BY
LATE THU NIGHT...MOISTURE WILL INCREASE YET AGAIN AS ANOTHER STORM
SYSTEM APPROACHES THE REGION FROM THE WEST. CHANCES FOR SHOWERS/FLT
RESTRICTIONS WILL PERSIST THROUGH AT LEAST SATURDAY MORNING. DRY
WEATHER SHOULD RETURN BY THE END OF THE WEEKEND.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...JOH
AVIATION...LG
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
350 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND
REACH THE EAST COAST BY LATE THURSDAY. ANOTHER LOW WILL APPROACH
FROM THE CENTRAL AND SOUTHERN PLAINS ON FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 348 PM EST WEDNESDAY...
UPDATED ISC GRIDS AND ZONE TO INCLUDE TORNADO WATCH 52 IN EFFECT
UNTIL 10 PM.
AS OF 320 PM EST WEDNESDAY...
THE WARM FRONT WILL SLOWLY LIFT NORTH THIS EVENING INTO
TONIGHT... AS A COLD FRONT ADVANCES EAST ACROSS THE REGION. THE
ATMOSPHERE IS BEING MORE UNSTABLE ACROSS OUR REGION...WITH THIN OF
CLOUDS/BREAKS ACROSS THE WESTERN MOUNTAINS. THE 7H-5H LAPS RATES
ON THE 19Z SPC MESOSCALE ANALYSIS ARE 7 TO 7.5 ACROSS THE WESTERN
MOUNTAINS. LOW LEVEL WINDS INCREASE TONIGHT AND WITH THE HIGH
SHEAR ENVIRONMENT...ANY BAND OF THUNDERSTORMS MAY PRODUCE STRONG
GUSTY WINDS AND HAIL.
NAM/SREF...WRFARW-RNK AND EVEN THE GFS WERE SHOWING AREAS OF SHOWERS
AND THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT IS FORECAST
TO COME THROUGH THE COUNTY WARNING AREA BY MIDNIGHT TONIGHT. EXPECT
THE MOST INTENSE STORMS AND THE THREAT OF HEAVIEST RAINFALL TO OCCUR
BETWEEN 21Z/4PM AND 03Z/10PM. WITH LOWER FFG CONSIDERED A FLOOD
WATCH FOR SOUTHEAST WEST VIRGINIA...BUT WITH FAST MOVING LINE
FLOODING MAY BE MORE LOCALIZED. WILL HAVE TO MONITOR AS AFTERNOON
PROGRESSES. COLDER AIR COMES IN TONIGHT BEHIND THE COLD FRONT.
USED A BLEND OF THE HRRR AND NAM FOR TEMPERATURES TONIGHT. LOWS WILL
RANGE FROM THE UPPER 30S IN THE NORTHWEST TO THE MID 50S IN THE
SOUTHEAST.
LOOKING AHEAD TO THURSDAY MORNING...THE COLD FRONT WILL BE WELL EAST
OF OUR AREA BY SUNRISE...AND BELIEVE ONLY ISOLATED SHOWERS...IF
ANY...WILL BE ALL THAT REMAIN ACROSS THE PIEDMONT AS HIGH PRESSURE
BUILDS IN FROM THE WEST. HIGH PRESSURE BUILD ACROSS THE MOUNTAINS
BY THURSDAY AFTERNOON. UNDER PLENTY OF SUNSHINE...HIGHS THURSDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE MID 70S IN THE
SOUTHEAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST WEDNESDAY...
HIGH PRESSURE MOVES OVERHEAD THU EVENING THEN EAST TO THE COAST
FRIDAY MORNING. THIS SHOULD BE A PATTERN CONDUCIVE FOR COOLER
VALLEY/PIEDMONT TEMPS WITH SOME WARMING AFTER MIDNIGHT...TOWARD DAWN
WESTERN RIDGES PER INCREASING SE/S FLOW.
MODELS ARE SHOWING AGREEMENT OVERALL IN BRINGING INCREASING MOISTURE
AHEAD OF THE NEXT SYSTEM RAPIDLY NORTHWARD INTO OUR AREA FRIDAY
MORNING...AND WITH RETREATING HIGH...MAY SEE A IN-SITU WEDGE SET
UP...SO LOWERED HIGHS SOME FROM MOS FRIDAY IN THE TYPICAL WEDGE
AREAS. WILL SEE RAIN CHANCES INCREASE FROM SW TO NE BY AFTN WITH
FLOW BECOMING SOUTHERLY. DIFFERENCES DO COME INTO PLAY ON BREAKDOWN
OF THE WEDGE WITH GFS SLOWEST AND NAM FASTEST. ATTM...LEANED TOWARD
A GFS/ECMWF SOLUTION AS THE NAM SEEMS TOO FAST GIVEN POTENTIAL WAVE
FORMING ALONG THE WARM FRONT OFF THE NC COAST FRIDAY AFTN.
MODELS ARE TRYING TO SHOW A LULL BETWEEN THE WARM FRONTAL/WAA PRECIP
FRIDAY AFTN AND THE COLD FRONT PRECIP FRI NIGHT-SAT MORNING. FOR NOW
WILL GO WITH THAT LULL TO BE FRIDAY EVENING BASED ON MODEL/HPC
CONSENSUS BUT STILL WITH MOISTURE STREAMING RAPIDLY NE AHEAD OF THE
COLD FRONT WILL KEEP POPS IN THE CHANCE RANGE...THEN BUMP IT TO
CATEGORICAL IN THE WEST OVERNIGHT FRIDAY AND SWINGING THE FRONT
ACROSS BY SAT AFTN...DRYING FROM WEST TO EAST. THIS WILL BE ANOTHER
ACTIVE FRONT WITH THUNDERSTORMS AND HEAVIER RAINS POSSIBLE.
ATTM...SPC HAS A SLIGHT RISK TO OUR WEST FRI NIGHT AND TIMING OF
THIS LINE AT NIGHT MAY INHIBIT SVR THREAT....ALTHOUGH QLCS LOOKS
LIKE A GOOD BET WITH 50-60 KNOT LOW LVL JET AND POTENTIAL FOR SOME
SPINUPS GIVEN THE GFS FORECAST AND DIRECTIONAL SHEAR AROUND 12Z SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 308 PM EST WEDNESDAY...
SATURDAY EVENING THE BACK EDGE OF AN AREA OF PRECIPITATION
ASSOCIATED WITH SATURDAYS COLD FRONTAL PASSAGE WILL BE EXITING
SOUTHSIDE VIRGINIA...AND NEIGHBORING SECTIONS OF NORTH CAROLINA.
NORTHWEST FLOW BEHIND THE FRONT WILL HELP GENERATE SOME UPSLOPE
RAIN/SNOW SHOWERS ACROSS PARTS OF SE WV...THAT WILL ISOLATED IN
COVERAGE AND LAST THROUGH EARLY SUNDAY MORNING.
SUNDAY THROUGH MONDAY...OUR NEXT NORTHERN STREAM CLIPPER SYSTEM WILL
RACE THROUGH THE OHIO VALLEY AND THEN THE CENTRAL APPALACHIANS.
PRECIPITATION IS EXPECTED TO START AS RAIN SHOWERS ACROSS SE WV ON
SUNDAY AFTERNOON. DURING THE OVERNIGHT HOURS...LOOK FOR COVERAGE TO
SPREAD FARTHER EAST AND BECOME A MIX OF RAIN AND SNOW...THE THE BULK
OF THE SNOW CONFINED TO SE WV...NEIGHBORING COUNTIES OF SW VA...AND
THE NORTHERN MOUNTAINS OF NC. NORTHWEST FLOW ON THE BACK SIDE OF THE
SYSTEM WILL ALLOW FOR A CONTINUATION OF UPSLOPE RAIN/SNOW SHOWERS
ACROSS THE MOUNTAINS ON MONDAY THAT WILL TREND TO ISOLATE RAIN
SHOWERS BY THE AFTERNOON.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BUILD OVER AND THEN EAST
OF THE REGION. THIS WILL ALLOW FOR AN END OF THE PRECIPITATION...AND
TREND TOWARDS MILDER CONDITIONS BY WEDNESDAY WITH SOUTHERLY FLOW
ESTABLISHING ITSELF. CLOUD COVER WILL ALSO INCREASE ON WEDNESDAY AS
LOW LEVEL FLOW GAINS A FETCH OF THE ATLANTIC AND MOISTURE IS
ADVECTED UPSLOPE ALONG THE CREST OF THE BLUE RIDGE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AS OF 1120 AM EST WEDNESDAY...
MVFR EXPECTED WITH POCKETS OF IFR/LIFR THIS AFTERNOON IN CLOUDS
AND CONVECTION. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE
THIS AFTERNOON INTO TONIGHT. THE COLD FRONT WILL APPROACH BLF AND
LWB THIS EVENING AND SHOULD BE EAST OF LYH AND DAN BY 09Z. A BKN
LINE OF SHOWERS AND THUNDERSTORMS LIKELY TO ACCOMPANY THE FRONTAL
PASSAGE...WITH TEMPORARY IFR TO MVFR CONDITIONS. FOLLOWING THE
COLD FRONT EXPECT A RETURN TO VFR WEATHER FOR LATE TONIGHT INTO
THURSDAY.
ANOTHER WARM FRONT WILL AFFECT THE REGION FRIDAY...WITH POSSIBLE
MVFR CIGS. A STRONG COLD FRONT SHOULD ARRIVE IN THE LATE FRIDAY
NIGHT-SAT TIME FRAME RESULTING IN WIDESPREAD MVFR/IFR DUE TO
SHOWERS AND THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...WP
LONG TERM...DS
AVIATION...AMS/KK/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
327 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND
REACH THE EAST COAST BY LATE THURSDAY. ANOTHER LOW WILL APPROACH
FROM THE CENTRAL AND SOUTHERN PLAINS ON FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 320 PM EST WEDNESDAY...
THE WARM FRONT WILL SLOWLY LIFT NORTH THIS EVENING INTO
TONIGHT... AS A COLD FRONT ADVANCES EAST ACROSS THE REGION. THE
ATMOSPHERE IS BEING MORE UNSTABLE ACROSS OUR REGION...WITH THIN OF
CLOUDS/BREAKS ACROSS THE WESTERN MOUNTAINS. THE 7H-5H LAPS RATES
ON THE 19Z SPC MESOSCALE ANALYSIS ARE 7 TO 7.5 ACROSS THE WESTERN
MOUNTAINS. LOW LEVEL WINDS INCREASE TONIGHT AND WITH THE HIGH
SHEAR ENVIRONMENT...ANY BAND OF THUNDERSTORMS MAY PRODUCE STRONG
GUSTY WINDS AND HAIL.
NAM/SREF...WRFARW-RNK AND EVEN THE GFS WERE SHOWING AREAS OF SHOWERS
AND THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT IS FORECAST
TO COME THROUGH THE COUNTY WARNING AREA BY MIDNIGHT TONIGHT. EXPECT
THE MOST INTENSE STORMS AND THE THREAT OF HEAVIEST RAINFALL TO OCCUR
BETWEEN 21Z/4PM AND 03Z/10PM. WITH LOWER FFG CONSIDERED A FLOOD
WATCH FOR SOUTHEAST WEST VIRGINIA...BUT WITH FAST MOVING LINE
FLOODING MAY BE MORE LOCALIZED. WILL HAVE TO MONITOR AS AFTERNOON
PROGRESSES. COLDER AIR COMES IN TONIGHT BEHIND THE COLD FRONT.
USED A BLEND OF THE HRRR AND NAM FOR TEMPERATURES TONIGHT. LOWS WILL
RANGE FROM THE UPPER 30S IN THE NORTHWEST TO THE MID 50S IN THE
SOUTHEAST.
LOOKING AHEAD TO THURSDAY MORNING...THE COLD FRONT WILL BE WELL EAST
OF OUR AREA BY SUNRISE...AND BELIEVE ONLY ISOLATED SHOWERS...IF
ANY...WILL BE ALL THAT REMAIN ACROSS THE PIEDMONT AS HIGH PRESSURE
BUILDS IN FROM THE WEST. HIGH PRESSURE BUILD ACROSS THE MOUNTAINS
BY THURSDAY AFTERNOON. UNDER PLENTY OF SUNSHINE...HIGHS THURSDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE MID 70S IN THE
SOUTHEAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST WEDNESDAY...
HIGH PRESSURE MOVES OVERHEAD THU EVENING THEN EAST TO THE COAST
FRIDAY MORNING. THIS SHOULD BE A PATTERN CONDUCIVE FOR COOLER
VALLEY/PIEDMONT TEMPS WITH SOME WARMING AFTER MIDNIGHT...TOWARD DAWN
WESTERN RIDGES PER INCREASING SE/S FLOW.
MODELS ARE SHOWING AGREEMENT OVERALL IN BRINGING INCREASING MOISTURE
AHEAD OF THE NEXT SYSTEM RAPIDLY NORTHWARD INTO OUR AREA FRIDAY
MORNING...AND WITH RETREATING HIGH...MAY SEE A IN-SITU WEDGE SET
UP...SO LOWERED HIGHS SOME FROM MOS FRIDAY IN THE TYPICAL WEDGE
AREAS. WILL SEE RAIN CHANCES INCREASE FROM SW TO NE BY AFTN WITH
FLOW BECOMING SOUTHERLY. DIFFERENCES DO COME INTO PLAY ON BREAKDOWN
OF THE WEDGE WITH GFS SLOWEST AND NAM FASTEST. ATTM...LEANED TOWARD
A GFS/ECMWF SOLUTION AS THE NAM SEEMS TOO FAST GIVEN POTENTIAL WAVE
FORMING ALONG THE WARM FRONT OFF THE NC COAST FRIDAY AFTN.
MODELS ARE TRYING TO SHOW A LULL BETWEEN THE WARM FRONTAL/WAA PRECIP
FRIDAY AFTN AND THE COLD FRONT PRECIP FRI NIGHT-SAT MORNING. FOR NOW
WILL GO WITH THAT LULL TO BE FRIDAY EVENING BASED ON MODEL/HPC
CONSENSUS BUT STILL WITH MOISTURE STREAMING RAPIDLY NE AHEAD OF THE
COLD FRONT WILL KEEP POPS IN THE CHANCE RANGE...THEN BUMP IT TO
CATEGORICAL IN THE WEST OVERNIGHT FRIDAY AND SWINGING THE FRONT
ACROSS BY SAT AFTN...DRYING FROM WEST TO EAST. THIS WILL BE ANOTHER
ACTIVE FRONT WITH THUNDERSTORMS AND HEAVIER RAINS POSSIBLE.
ATTM...SPC HAS A SLIGHT RISK TO OUR WEST FRI NIGHT AND TIMING OF
THIS LINE AT NIGHT MAY INHIBIT SVR THREAT....ALTHOUGH QLCS LOOKS
LIKE A GOOD BET WITH 50-60 KNOT LOW LVL JET AND POTENTIAL FOR SOME
SPINUPS GIVEN THE GFS FORECAST AND DIRECTIONAL SHEAR AROUND 12Z SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 308 PM EST WEDNESDAY...
SATURDAY EVENING THE BACK EDGE OF AN AREA OF PRECIPITATION
ASSOCIATED WITH SATURDAYS COLD FRONTAL PASSAGE WILL BE EXITING
SOUTHSIDE VIRGINIA...AND NEIGHBORING SECTIONS OF NORTH CAROLINA.
NORTHWEST FLOW BEHIND THE FRONT WILL HELP GENERATE SOME UPSLOPE
RAIN/SNOW SHOWERS ACROSS PARTS OF SE WV...THAT WILL ISOLATED IN
COVERAGE AND LAST THROUGH EARLY SUNDAY MORNING.
SUNDAY THROUGH MONDAY...OUR NEXT NORTHERN STREAM CLIPPER SYSTEM WILL
RACE THROUGH THE OHIO VALLEY AND THEN THE CENTRAL APPALACHIANS.
PRECIPITATION IS EXPECTED TO START AS RAIN SHOWERS ACROSS SE WV ON
SUNDAY AFTERNOON. DURING THE OVERNIGHT HOURS...LOOK FOR COVERAGE TO
SPREAD FARTHER EAST AND BECOME A MIX OF RAIN AND SNOW...THE THE BULK
OF THE SNOW CONFINED TO SE WV...NEIGHBORING COUNTIES OF SW VA...AND
THE NORTHERN MOUNTAINS OF NC. NORTHWEST FLOW ON THE BACK SIDE OF THE
SYSTEM WILL ALLOW FOR A CONTINUATION OF UPSLOPE RAIN/SNOW SHOWERS
ACROSS THE MOUNTAINS ON MONDAY THAT WILL TREND TO ISOLATE RAIN
SHOWERS BY THE AFTERNOON.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BUILD OVER AND THEN EAST
OF THE REGION. THIS WILL ALLOW FOR AN END OF THE PRECIPITATION...AND
TREND TOWARDS MILDER CONDITIONS BY WEDNESDAY WITH SOUTHERLY FLOW
ESTABLISHING ITSELF. CLOUD COVER WILL ALSO INCREASE ON WEDNESDAY AS
LOW LEVEL FLOW GAINS A FETCH OF THE ATLANTIC AND MOISTURE IS
ADVECTED UPSLOPE ALONG THE CREST OF THE BLUE RIDGE.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 1120 AM EST WEDNESDAY...
MVFR EXPECTED WITH POCKETS OF IFR/LIFR THIS AFTERNOON IN CLOUDS
AND CONVECTION. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE
THIS AFTERNOON INTO TONIGHT. THE COLD FRONT WILL APPROACH BLF AND
LWB THIS EVENING AND SHOULD BE EAST OF LYH AND DAN BY 09Z. A BKN
LINE OF SHOWERS AND THUNDERSTORMS LIKELY TO ACCOMPANY THE FRONTAL
PASSAGE...WITH TEMPORARY IFR TO MVFR CONDITIONS. FOLLOWING THE
COLD FRONT EXPECT A RETURN TO VFR WEATHER FOR LATE TONIGHT INTO
THURSDAY.
ANOTHER WARM FRONT WILL AFFECT THE REGION FRIDAY...WITH POSSIBLE
MVFR CIGS. A STRONG COLD FRONT SHOULD ARRIVE IN THE LATE FRIDAY
NIGHT-SAT TIME FRAME RESULTING IN WIDESPREAD MVFR/IFR DUE TO
SHOWERS AND THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/KK
NEAR TERM...AMS/KK
SHORT TERM...WP
LONG TERM...DS
AVIATION...AMS/KK/PM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 PM CST WED FEB 29 2012
.SHORT TERM...LATE THIS AFTERNOON THROUGH SATURDAY NIGHT
314 PM CST WED FEB 29 2012
AT 3 PM...A 913 MB SURFACE LOW WAS LOCATED JUST EAST OF ROCHESTER
MINNESOTA. PRECIPITATION AND WARMER AIR CONTINUES TO ROTATE AROUND
THIS LOW PRESSURE AREA. IN ADDITION TO THE WARM AIR...THE INFRARED
SATELLITE IMAGERY AND MODEL SOUNDINGS ARE SHOWING THAT WE ARE
LOSING OUR ICE CRYSTAL SEEDING. THIS IS GREATLY COMPLICATING THE
PRECIPITATION TYPE FORECASTING. IN AREAS WHERE THE REFLECTIVITIES
ARE GREATER THAN 30 DECIBELS...THE PRECIPITATION IS IN THE FORM OF
SNOW. AT THIS TIME...IT LOOKS LIKE UP TO AN INCH OF ADDITION SNOW
WILL BE POSSIBLE EAST OF AN EAU CLAIRE TO DUBUQUE LINE...AND SOUTH
OF A LINE FROM CHARLES CITY IOWA TO LANCASTER WISCONSIN. DUE TO
THIS SNOW...WILL KEEP THE WINTER WEATHER HEADLINES RUNNING THROUGH
6 PM TONIGHT. ELSEWHERE...THE PRECIPITATION IS MAINLY IN THE FORM
OF RAIN OR DRIZZLE. THERE HAS EVEN BEEN A FEW REPORTS OF FREEZING
DRIZZLE OR RAIN ON THE HIGHER ELEVATIONS OF SOUTHEAST MINNESOTA...
NORTHEAST IOWA...AND IN THE BLUFF AREAS OF WESTERN WISCONSIN. WITH
THIS BEING SO HIT OR MISS JUST HANDLING THIS AS A SPECIAL WEATHER
STATEMENT.
SINCE WE CONTINUE TO SEE SUSTAINED WINDS IN THE 25 TO 35 MPH RANGE
AND OCCASIONAL WIND GUSTS UP TO 45 MPH...WILL LEAVE THE WIND
ADVISORY UP THROUGH 6 PM TODAY ACROSS NORTHEAST IOWA AND SOUTHWEST
WISCONSIN.
ON THURSDAY NIGHT AND FRIDAY...THE 29.12Z NAM/WRF CAME IN MUCH
STRONGER...WETTER...AND FURTHER NORTHWEST THAN THE GFS...ECWMF...AND
UKMET. THE MAIN REASON FOR THIS IS THAT IT PHASES THE NORTHERN AND
SOUTHERN STREAMS TOGETHER. MEANWHILE THE REMAINING MODELS HAVE ONE
SHORT WAVE TROUGH MOVING THROUGH THURSDAY NIGHT...AND TWO OTHER
SHORTS SHIRTING THE AREA /ONE TO THE NORTH AND ANOTHER TO THE
SOUTHEAST/ ON FRIDAY. SINCE THE NAM/WRF HAS BEEN PHASING THE
NORTHERN AND SOUTHERN STREAMS TOO MUCH...THE FORECAST WAS TRENDED
TOWARD THE OTHER MODEL SOLUTIONS. SNOW TOTALS ON THURSDAY
NIGHT...LOOK TO LESS THAN INCH. NOT AS SURE ON FRIDAY DUE TO THE
POTENTIAL OF RAIN POSSIBLY MIXING IN WITH THE SNOW AT TIMES.
FROM FRIDAY NIGHT INTO SATURDAY...A LONG WAVE TROUGH WILL MOVE
EAST ACROSS THIS AREA. THERE APPEARS THAT THERE WILL BE ENOUGH
MOISTURE AND LIFT ASSOCIATED WITH THIS SYSTEM TO MAINTAIN SOME
LIGHT RAIN AND SNOW IN THE FORECAST. AS A RESULT...KEPT THE
PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT RANGE.
.LONG TERM...SUNDAY THROUGH TUESDAY
314 PM CST WED FEB 29 2012
ON TUESDAY...THE 29.12Z MODELS CONTINUE TO SHOW THAT THERE WILL BE
STRONG WARM AIR ADVECTION AHEAD OF THE SYSTEM MOVING OUT OF THE
NORTHERN PLAINS. BOTH THE ECMWF ARE SUGGESTING THAT TEMPERATURES
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR WILL CLIMB INTO THE
50S. WHILE THESE TEMPERATURES LOOK REASONABLE...THERE IS SOME
CONCERN ON HOW WARM TEMPERATURES WILL GET ACROSS THE AREAS WHICH
RECEIVED THE DEEP SNOW PACK LAST NIGHT. THE ALL BLEND AND CONS
BLEND WOULD SUGGEST TEMPERATURES IN THE UPPER 40S. HOWEVER THIS
LOOKS TO BE TOO WARM WITH MUCH SNOW ON THE GROUND...SO COOLED THE
TEMPERATURES DOWN INTO THE LOWER AND MID 40S.
&&
.AVIATION...THROUGH 18Z THURSDAY
1222 PM CST WED FEB 29 2012
LATEST 17Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTH
CENTRAL MINNESOTA WITH THE LATEST METARS SHOWING MVFR TO IFR
CEILINGS ACROSS MUCH OF THE AREA...WITH ISOLATED POCKETS OF LIFR
CONDITIONS. MAIN CONCERN THROUGH TAF PERIOD IS LOW LEVEL STRATUS
DECK WRAPPING AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES. LATEST 29.12Z NAM/GFS AND 29.15Z RUC DO INDICATE SURFACE
LOW TO SLOWLY MOVE EAST INTO WESTERN MICHIGAN BY 06Z THURSDAY.
BUFKIT SOUNDINGS FROM THE DETERMINISTIC MODELS SHOW LOW LEVEL
STRATUS TO WRAP AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES THROUGH TAF PERIOD. HAVE INTRODUCED MVFR/IFR CEILINGS
THROUGH THE TAF FORECAST PERIOD. LATEST MOSAIC RADAR INDICATING
SNOW BAND OVER SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH
VISIBILITIES BEING REDUCED TO ONE MILE TO TWO MILES PER LATEST
METARS. THIS BAND SHOULD LIFT NORTHEAST OF BOTH TAF SITES BY 20Z
WEDNESDAY AND ALLOW FOR VISIBILITIES TO IMPROVE AFTER 20Z.
&&
.HYDROLOGY...
346 AM CST WED FEB 29 2012
A GOOD DEAL OF PRECIPITATION FELL LAST NIGHT AS THE MAIN SURGE OF
MOIST AIR ARRIVED. MORNING PRECIPITATION REPORTS INDICATE BETWEEN A
HALF-INCH AND THREE-QUARTERS OF AN INCH ACROSS NORTHEAST IOWA AND
SOUTHWEST WISCONSIN. SOME MINOR WITHIN BANK RISES ON TRIBUTARY
CREEKS AND RIVERS HAS OCCURRED.
FROM SOUTHEAST MN INTO CENTRAL AND NORTHERN WI...AMOUNTS WERE HIGHER
WITH WIDESPREAD REPORTS BETWEEN 1 AND 1.5 INCHES. SOME SPOTS SAW
JUST OVER 1.75 INCHES OF WATER. THE HIGHEST AMOUNTS WERE SEEN FROM
THE ZUMBRO AND WHITEWATER WATERSHEDS...INTO THE TREMPEALEAU AND
BLACK RIVER BASINS. SIGNIFICANT RISES ARE OCCURING IN THESE RIVER
SYSTEMS...WITH SOME SPOTS GETTING CLOSE TO BANKFULL AND FLOOD STAGE.
CURRENTLY...THE SYSTEM IS SPINNING OVERHEAD...DROPPING MORE SNOW AND
DRIZZLE. THIS SHOULD NOT AMOUNT TO A GREAT DEAL MORE WATER CONTENT.
SO THE FEELING IS WE WILL SEE THE MAJORITY OF RIVERS PEAK AND FALL
TONIGHT...IF THEY HAVE NOT ALREADY DONE SO.
THIS RAINFALL ON THE FROZEN SOIL ALSO LED TO WIDESPREAD PONDING OF
WATER...AS IT COULD NOT SOAK IN.
THE STORM DROPPED OVER 15 INCHES OF SNOW ACROSS THE UPPER BLACK
RIVER BASIN...SO AS THIS MELTS...EXPECT THE BLACK TO CONTINUE
RUNNING HIGHER THAN NORMAL INTO NEXT WEEK.
WE ARE ALSO MONITORING THE NEXT STORM SYSTEM FOR THE END OF THE
WEEK. ANY ADDITIONAL WATER COULD LEAD TO RENEWED RISES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 PM CST WED FEB 29 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ032>034-043-044-054-055-061.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ054-055-061.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ
HYDROLOGY...WELVAERT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
245 PM CST WED FEB 29 2012
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW
PRESSURE NOW ENTERING SOUTHWEST WISCONSIN THIS AFTERNOON.
PRECIPITATION WITH THIS MAIN CIRCULATION HAS BEEN BLOSSOMING ACROSS
CENTRAL AND NORTHEAST WISCONSIN THIS AFTERNOON...WITH VSBYS DROPPING
TO 3/4SM IN LIGHT SNOW FROM WISCONSIN RAPIDS TO WAUSAU.
TEMPERATURES AND DEWPOINTS HAVE WARMED INTO THE MIDDLE AND UPPER 30S
OVER THE FOX VALLEY...BAYSHORE...AND LAKESHORE...WHERE PRECIP HAS
BEEN MAINLY RAIN AND DRIZZLE THIS AFTERNOON. AS THE LOW TRACKS
ACROSS CENTRAL WISCONSIN THIS EVENING...PRECIP TYPE AND
ACCUMULATIONS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE ENE ACROSS CENTRAL
WISCONSIN THIS EVENING. WILL NO LONGER BE FEELING THE EFFECTS OF
THE WARM CONVEYOR BELT...BUT MOISTURE WRAPPING ALL THE WAY AROUND
INTO THE COMMA HEAD WILL LEAD TO WIDESPREAD PRECIPITATION CONTINUING
FOR MUCH OF THE EVENING. THE HEAVIEST PRECIP SHOULD FALL WITHIN AND
ON THE NORTHERN FLANK OF THE CIRCULATION CENTER WHICH SHOULD RUN
FROM ABOUT MARSHFIELD TO DOOR COUNTY. BECAUSE COLDER AIR TO -6C AT
850MB WILL FILTER ACROSS NORTHEAST WISCONSIN...PRECIPITATION TYPE
WILL CHANGE TO ALL SNOW...EVEN NEXT TO THE LAKESHORE. AN ADDITIONAL
INCH OR TWO OF SNOW WILL BE POSSIBLE NORTHWEST OF THE FOX VALLEY AND
BAY SHORE AND OVER THE HIGHER TERRAIN THROUGH THIS EVENING WHERE
TEMPERATURES WILL FALL INTO THE 31-34 DEGREE RANGE. ABOVE FREEZING
TEMPERATURES WILL INITIALLY LIMIT ACCUMS OVER EAST-CENTRAL AND FAR
NORTHEAST WISCONSIN...BUT THOSE LOCATIONS COULD STILL SEE A HALF
INCH TO AN INCH AS TEMPS FALL THIS EVENING. BECAUSE OF THE
POSSIBILITY OF ANOTHER COUPLE INCHES OF SNOW WHICH COULD LEAD TO
RENEWED TRAVEL WOES...WILL LEAVE WINTER WEATHER HEADLINES ALONE.
SNOW WILL BE PUSHING ON TO THE EAST BY LATE IN THE EVENING LEAVING
CLOUDY SKIES PREVAILING ACROSS THE REGION. PLENTY OF FLURRY
ACTIVITY EXISTING ALL THE WAY TO WESTERN MINNESOTA...SO WILL HAVE TO
LEAVE A MENTION THROUGH THE REST OF THE NIGHT. LOW TEMPS RANGING
FROM THE MID 20S WEST TO AROUND 30 EAST.
THURSDAY...LOW PRESSURE WILL CONTINUE EAST TO THE EASTERN GREAT
LAKES. CYCLONIC FLOW WILL HANG AROUND FOR MUCH OF THE MORNING...SO
FIGURE SKY CONDITIONS WILL REMAIN CLOUDY. SOME BREAKS IN THE CLOUDS
ARE LIKELY IN THE AFTERNOON WHEN THE LOW LEVEL MOISTURE THINS OUT
AND THE FLOW BECOMES LIGHT AND WESTERLY. HIGHS IN THE MID 30S TO
AROUND 40F.
.LONG TERM...THU NGT THRU NXT WED. MDLS HAVE COME INTO BETTER
AGREEMENT WITH REGARDS TO A BROAD LONGWAVE TROF PUSHING ACROSS THE
CONUS DURING THE FIRST HALF OF THE EXTENDED PERIOD. STILL WATCHING
A SYSTEM PRECEDING THIS TROF WHICH COULD BRING A MIX OF PCPN TYPES
TO NE WI ON FRI. MEAN FLOW TENDS TO FLATTEN BY EARLY NXT WEEK
ALLOWING FOR MILD PACIFIC AIR TO RUSH ACROSS THE CONUS. DEPENDING
ON THE AMOUNT OF SNOW STILL ON THE GROUND...SOME PARTS OF CNTRL/
E-CNTRL WI COULD PUSH THE 50 DEG MARK BY TUE BEFORE THE NXT CDFNT
ARRIVES WITH THE NXT CHC OF PCPN.
THE LONGWAVE TROF MOVES THRU THE ROCKIES THU NGT AND ENTERS THE
PLAINS TOWARD DAYBREAK. AS THIS OCCURS...A SFC LOW IS FCST TO DVLP
OVER THE CNTRL/SRN PLAINS AND MOVE NE TOWARD THE OZARKS/MO VALLEY
AREA. WAA TO OVERSPREAD WI WITH ENUF MSTR EVIDENT TO BRING PCPN
INTO PARTS OF THE FCST AFTER MIDNGT. TEMPS WOULD BE COLD ENUF SUCH
THAT ANY PCPN WOULD BE SNOW...BUT ANY ACCUMULATIONS WOULD BE VERY
MINOR.
QSTNS REMAIN AS TO THE EXACT TRACK OF THE SFC LOW AS IT HEADS NE
TOWARD SRN SECTIONS OF THE GREAT LKS ON FRI. THE NAM REMAINS A
WESTWARD TRACK OUTLIER PRIMARILY DUE TO TRYING TO PHASE A NRN
PIECE OF SHORTWAVE TROF WITH THE SFC LOW. THE GEM MODEL TRACKS THE
SFC LOW NEWD INTO SW/CNTRL SECTIONS OF LWR MI...WHILE THE GFS/UKMET/
ECMWF NOW ALL PREFER A MORE ERN ROUTE AND TAKE THE LOW PRES TOWARD
NE INDIANA/SE LWR MI. SINCE THIS SYSTEM IS JUST COMING ASHORE TODAY
(WED)...TRACK WL LIKELY WAFFLE A BIT MORE BEFORE SETTLING DOWN...
THUS HAVE LEANED TOWARD THE MORE CONSISTENT GFS/UKMET/ECMWF WHICH
WOULD BRING AN INCH OR TWO OF ACCUMULATION TO NE WI. HAVE RAISED
POPS TO LIKELY FOR ALMOST THE ENTIRE FCST AERA AND GONE MORE SNOW
THAN RAIN FOR ERN WI.
SNOW CHCS TO CONT THRU AT LEAST FRI EVENING BEFORE TAPERING OFF
FROM SOUTH TO NORTH AS THE SFC LOW MOVES INTO SE ONTARIO. COULD
SEE AN ADDL INCH OR TWO OF ACCUMULATION...MAINLY ACROSS THE NRN
WI. SYSTEM CONTS TO LIFT NE TOWARD THE CANADIAN MARITIMES ON SAT
WITH A TRAILING SHORTWAVE TROF/EMBEDDED SHORTWAVES STILL MOVING
THRU WI. WL NEED TO CARRY SOME SNOW SHWR ACTIVITY THRU THE DAY
WITH THE BETTER CHCS ACROSS THE NORTH AS WINDS TURN W-NW WITH SOME
PSBL LK ENHANCEMENT. TEMPS TO CONT A DOWNWARD TREND WITH HI TEMPS
GENERALLY IN THE 30-35 DEG RANGE.
THE LONGWAVE TROF IS THEN EXPECTED TO MVOE THRU THE RGN SAT NGT
INTO SUNDAY WITH VARIOUS PIECES OF SHORTWAVE ENERGY DROPPING SE IN
THE NW FLOW ALOFT. NE WI ALSO RESIDE UNDER THE FAVORABLE LEFT EXIT
RGN OF THE UPR JET FOR ADDED LIFT. EXPECT TO SEE AT LEAST ISOLATED
SNOW SHWRS ACROSS THE FCST AREA BOTH SAT NGT AND SUNDAY WITH A
MINOR ACCUMULATION PSBL WHERE ANY SNOW SHWRS BECOME MORE PRONOUNCED.
SUNDAY ALSO LOOKS TO BE THE COLDEST DAY OF THE EXTENDED FCST WITH
MAX TEMPS MAINLY IN THE 25-30 DEG RANGE. A WEAK AREA OF HI PRES IS
THEN FCST TO BUILD ACROSS THE WRN GREAT LKS RGN SUNDAY NGT AND
RESIDE TO OUR EAST ON MON. ANY LINGERING SNOW SHWRS SHOULD END
RATHER QUICKLY WITH WINDS BACKING TO THE S-SW BY MON ON THE
BACKSIDE OF THE HI PRES. COOL START TO MON WL LIMIT AMOUNT OF
DIURNAL WARMING EVEN AS A SURGE OF WARMER AIR ALOFT PUSHES INTO
THE STATE.
INCREASING S-SW WINDS MON NGT WL SEND A WRMFNT NWD WITH MUCH
MILDER AIR STREAMING INTO NE WI. A NEW...BROAD UPR TROF IS PROGGED
TO MOVE INTO THE CNTRL CONUS ON TUE AND HELP PUSH A CDFNT ACROSS
THE UPR MIDWEST. MOST OF THE FORCING/LIFT APRS TO BE BEHIND THE
FNT...THUS HAVE KEPT TUE DRY AND MILD WITH MAX TEMPS SURPASSING
THE 40 DEG MARK. IF CLOUDS CAN STAY AWAY LONG ENUF...PARTS OF
CNTRL/E-CNTRL WI COULD REACH 50 DEGS. THE CDFNT PUSHES THRU WI TUE
NGT AND THEN THE MDLS DVLP SEVERAL WAVES ALONG THE FNT WHICH WOULD
HELP FOCUS PCPN ACROSS THE FCST AREA ON WED. BASED ON PROJECTED
LOCATION OF THE CDFNT AND SFC WAVES...HAVE GONE WITH A HI CHC POP
FOR THE VAST MAJORITY OF NE WI. ANOTHER PBLM WL BE PCPN TYPE AS
COOLER AIR TO SETTLE OVER THE NW HALF OF WI. HAVE GONE WITH A
RAIN/SNOW MIX FOR N-CNTRL WI...BUT KEPT PCPN AS ALL RAIN IN THE
CENTRAL AND EAST.
&&
.AVIATION...STRONG LOW PRESSURE WILL PASS ACROSS THE STATE THROUGH
THIS EVENING BEFORE DEPARTING TO THE EAST. HEAVY SNOW HAS SHIFTED
INTO THE UPPER PENINSULA...BUT WRAP AROUND SNOW SHOWERS WILL PASS
OVER THE TAF SITES THIS AFTERNOON INTO EARLY THIS EVENING. IFR TO
LIFR VSBYS POSSIBLE IN ANY SNOW SHOWERS. ONCE THE SNOW
ENDS...FLURRIES SHOULD HANG ON THROUGH MUCH OF THE EVENING.
VARIABLE CIGS UPSTREAM SUGGEST HIGH END IFR TO MVFR CIGS THROUGH
THE REST OF THE TAF PERIOD UNDER CYCLONIC FLOW.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>013-018-019-030.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ035-
036.
&&
$$
MPC/AK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CST WED FEB 29 2012
.SHORT TERM...
1116 AM CST WED FEB 29 2012
A BAND OF MODERATE TO HEAVY SNOW ROTATING AROUND SURFACE LOW OVER
SOUTH CENTRAL MINNESOTA WILL PROGRESS EASTWARD INTO NORTHEAST IOWA
AND SOUTHWEST WISCONSIN THIS AFTERNOON. THE COMBINATION OF SNOW
AND BLOWING SNOW WILL REDUCE VISIBILITIES TO LESS THAN A MILE
ACROSS THIS AREA. THEREFORE...WE WILL BE ISSUING A WINTER WEATHER
ADVISORY FOR NORTHEAST IOWA AND SOUTHWEST WISCONSIN THROUGH 6 PM.
.LONG TERM...SATURDAY THROUGH TUESDAY
346 AM CST WED FEB 29 2012
GOOD CONSENSUS AMONG 29.00Z MEDIUM RANGE MODELS FOR THE LONGWAVE
TROUGH TO SLOWLY PROGRESS EAST OF THE AREA SAT/SUN. A COLD LOW LEVEL
AIRMASS SETTLES OVER THE AREA FOR SAT INTO SUN. SFC-500MB FLOW
REMAINS CYCLONIC WITH SURGES OF MOISTURE/WEAK SHORTWAVES RIPPLING
SOUTHEAST THRU THE FLOW PASSING ACROSS THE REGION. SMALL -SN/FLURRY
CHANCES SAT/SUN LOOK REASONABLE AT THIS TIME. MODELS REMAIN IN GOOD
AGREEMENT FOR THE PATTERN TO BE PROGRESSIVE AND STRONG RIDGING ALOFT
AND BROAD LOWER LEVEL WARM ADVECTION TO SPREAD ACROSS THE NORTH
CENTRAL CONUS FOR MON/TUE. TEMPS LOOKING TO CLIMB WELL ABOVE NORMAL
FOR EARLY NEXT WEEK...AND THE WELL TRENDED WITH THE MODEL/ENSEMBLE
CONSENSUS DATA SET. AGAIN STAYED WITH THE MODEL/ENSEMBLE CONSENSUS
IN THE SAT-TUE FCST GRIDS.
&&
.AVIATION...THROUGH 18Z THURSDAY
1222 PM CST WED FEB 29 2012
LATEST 17Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTH
CENTRAL MINNESOTA WITH THE LATEST METARS SHOWING MVFR TO IFR
CEILINGS ACROSS MUCH OF THE AREA...WITH ISOLATED POCKETS OF LIFR
CONDITIONS. MAIN CONCERN THROUGH TAF PERIOD IS LOW LEVEL STRATUS
DECK WRAPPING AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES. LATEST 29.12Z NAM/GFS AND 29.15Z RUC DO INDICATE SURFACE
LOW TO SLOWLY MOVE EAST INTO WESTERN MICHIGAN BY 06Z THURSDAY.
BUFKIT SOUNDINGS FROM THE DETERMINISTIC MODELS SHOW LOW LEVEL
STRATUS TO WRAP AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES THROUGH TAF PERIOD. HAVE INTRODUCED MVFR/IFR CEILINGS
THROUGH THE TAF FORECAST PERIOD. LATEST MOSAIC RADAR INDICATING
SNOW BAND OVER SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH
VISIBILITIES BEING REDUCED TO ONE MILE TO TWO MILES PER LATEST
METARS. THIS BAND SHOULD LIFT NORTHEAST OF BOTH TAF SITES BY 20Z
WEDNESDAY AND ALLOW FOR VISIBILITIES TO IMPROVE AFTER 20Z.
&&
.HYDROLOGY...
346 AM CST WED FEB 29 2012
AS MUCH AS 0.50 TO 1.00 INCH OF RAIN FELL ACROSS THE FCST AREA
LATE TUE/TUE NIGHT. THERE IS NOT MUCH SNOW AROUND CURRENTLY...BUT
THE GROUND REMAINS FROZEN WITH SOME RUN-OFF OCCURRING FROM THESE
RAINS. MINOR RISES ARE OCCURRING ON MANY OF THE THE TRIBUTARY CREEKS
AND STREAMS AROUND THE AREA BUT REMAIN WELL WITHIN BANKFULL EARLY
THIS MORNING. WATER LEVEL TRENDS WILL CONTINUE TO BE MONITORED.
ADDITIONAL RAIN AMOUNTS THRU TODAY WILL MAINLY BE LESS THAN ONE-
QUARTER INCH.
THERE IS STILL SOME ICE IN THE CREEKS AND RIVERS. WHILE LIKELY NOT A
LARGE THREAT AS ICE COVER IS WELL BELOW AVERAGE THIS YEAR...IF
ENOUGH RUNOFF OCCURS...IT IS POSSIBLE THAT A RISE IN THE WATER LEVEL
COULD BREAK UP SOME OF THE ICE...AND SEND IT DOWNSTREAM. UNSAFE ICE
CONDITIONS...AND EVEN SOME ICE JAMS...COULD OCCUR. BLOCKED OR FROZEN
CULVERTS MAY RESULT IN POOR DRAINAGE IN SOME SPOTS...SO THERE COULD
BE SOME LOCALIZED PONDING AS WELL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1116 AM CST WED FEB 29 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ032>034-043-044-054-055-061.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ054-055-061.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...DTJ
LONG TERM....RRS
AVIATION...DTJ