Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/16/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
941 AM MST TUE FEB 14 2012
.UPDATE...12Z GJT SOUNDING AND CURRENT RADAR/SATELLITE IMAGERY
SHOW A RATHER MOIST AND UNSTABLE AIRMASS OVER WESTERN COLORADO.
THERE IS ENOUGH MID LEVEL INSTABILITY TO WARRANT A SLIGHT CHANCE
OF SNOW SHOWERS SNEAKING ONTO THE NEARBY PLAINS LATE THIS
AFTERNOON SO ADDED A LOW COVERAGE OF SNOW SHOWERS IN/NEAR THE
FOOTHILLS. LATEST HRRR COMPOSITE REFLECTIVITY SHOWS THIS AS WELL.
OTHER THAN THAT...SNOW SHOWERS WILL BECOME MORE WIDESPREAD IN THE
HIGH COUNTRY THROUGH THE AFTERNOON AS ALREADY FORECAST.
&&
.AVIATION...ONLY CHANGE WOULD BE TO ADD A LITTLE MORE MID LEVEL
CLOUDINESS AND PERHAPS A VCSH WITH ISOLATED SNOW SHOWER POSSIBLY
DRIFTING OFF THE FRONT RANGE AFTER 21Z.
&&
.PREV DISCUSSION... /ISSUED 403 AM MST TUE FEB 14 2012/
SHORT TERM...UPPER LEVEL LOW IS CURRENTLY SPINNING OVER SOUTHEAST
NEVADA AND SOUTHWEST UTAH. THIS LOW WILL DROP INTO NORTHERN ARIZONA
TODAY AND THEN MOVE ACROSS NORTHERN NEW MEXICO TONIGHT. MOISTURE
AHEAD OF THIS SYSTEM IS STREAMING OVER WESTERN COLORADO. RADAR
SHOWING SCATTERED SHOWERS OVER WESTERN COLORADO. EXPECT THE SHOWERS
TO CONTINUE THROUGH THE DAY TODAY AND THIS EVENING. MODELS
SHOWING THE BEST PLUME OF MOISTURE STAY NORTH OF I-70. THIS
MOISTURE COMBINED WITH WEAK QG LIFT...OROGRAPHIC LIFT AND MID
LEVEL INSTABILITY...WILL PRODUCE SNOW...MAINLY OVER THE MOUNTAINS.
BEST CHANCE FOR SNOW AND THE HEAVIEST SNOW...WILL BE OVER THE
MOUNTAINS OF JACKSON COUNTY AND NORTHERN GRAND COUNTY. EXPECT SNOW
AMOUNTS TO BE 1-5 INCHES WITH LOCALLY HIGHER AMOUNTS OVER THE
HIGHEST PEAKS OF WESTERN JACKSON COUNTY. TO THE SOUTH OF THIS
AREA...INCLUDING SUMMIT COUNTY AND THE I-70 CORRIDOR...ONLY EXPECT
0-2 INCHES OF SNOW THROUGH TONIGHT.
FOR NORTHEAST COLORADO...CLOUDS WILL INCREASE THIS AFTERNOON AS THIS
SYSTEM NEARS THE REGION. HIGHS TODAY WILL CLIMB ABOVE FREEZING
AGAIN. OVER SOUTHERN FOOTHILLS AND PALMER DIVIDE...WARM AIR
ADVECTION IN ADVANCE OF THE STORM SYSTEM WILL PUSH HIGHS INTO THE
40S. IN THE FORT COLLINS AND GREELEY AREAS...MORE CLOUD COVER AND
NORTHERLY WINDS USHERING COOLER AIR WILL KEEP TEMPERATURES SLIGHTLY
BELOW YESTERDAY`S READINGS (LOWER TO MID 40S). MODELS NOT SHOWING
ANY PRECIPITATION FOR TONIGHT. CAN NOT RULE OUT A FEW WEAK SNOW
SHOWERS...MAINLY THIS EVENING DUE TO WEAK QG ASCENT...MID LEVEL
INSTABILITY AND MID LEVEL MOISTURE.
LONG TERM...MODELS CONTINUE TO SHOW THE MAIN STORM TRACK
REMAINING WELL TO THE SOUTH OF COLORADO DURING THE UPCOMING WEEK.
THE NEXT IN THE SERIES OF UPPER AIR PERTABATIONS IS FORECAST TO
DIVE ALMOST DUE SOUTH OUT OF THE PACIFIC NORTHWEST AND DOWN THE
WEST SIDE OF A BROAD UPPER LEVEL TROUGH OVER THE WESTERN CONUS.
BEFORE THIS HAPPENS...THE SHORTWAVE TROUGH PASSING TO THE SOUTH OF
COLORADO TODAY/TONIGHT WILL MOVE AWAY FROM COLORADO ON WEDNESDAY
RESULTING IN A DECREASE IN SNOW SHOWER COVERAGE IN THE HIGH
COUNTRY AND CLEARING SKIES AT LOWER ELEVATIONS DURING THE
AFTERNOON. THIS BREAK IN PRECIPITATION WILL BE SHORT-LIVED WITH
THE NEXT UPPER AIR SYSTEM MOVING OVER THE LOWER DESERT SOUTHWEST.
00Z AND 06Z MODEL RUNS SHOW THIS LOW DIVING EVEN FARTHER SOUTH
AWAY FROM COLORADO...CONSEQUENTLY HAVING LESS OF AN IMPACT ON
NORTH CENTRAL AND NORTHEAST COLORADO. FOR NOW LEFT IN SCATTERED
POPS IN THE MTN ZONES FOR WEDNESDAY NIGHT AND THURSDAY MORNING TO
ACCOUNT FOR A WEAK SHORTWAVE SWINGING DOWN FROM WYOMING. HOWEVER
DO NOT SEE THIS DISTURBANCE PRODUCING ANY PCPN ON THE PLAINS SINCE
THE LOW LEVEL FLOW IS FORECAST TO REMAIN WEST-NORTHWESTERLY.
CONDITIONS DRY WITH SLIGHT WARMING ON FRIDAY WITH NORTHWEST FLOW
OVER THE AREA. WARMING CONTINUES ON SATURDAY WITH PASSAGE OF A
WEAK SHORTWAVE RIDGE ACCORDING TO THE GFS AND ECMWF. BEYOND
SATURDAY...MODELS BEGIN TO DIFFER. GFS SHOWS A DEEP TROUGH CARVING
OUT OVER THE WESTERN CONUS SUNDAY INTO MONDAY...WHILE THE ECMWF
HANGS ONTO NORTHWEST FLOW AT LEAST THROUGH SUNDAY NIGHT...THEN IT
FORMS AN OPEN WAVE TROUGH OVER THE CENTRAL ROCKY MTN REGION AREA
ON MONDAY. DUE TO THE UNCERTAINTY IN THE MODELS...WILL MAKE ONLY
MINOR CHANGES TO THE FORECAST GRIDS BEYOND SATURDAY. THIS INCLUDES
ADDING A BIT MORE CLOUD COVER AND RAISING POPS SLIGHTLY IN THE
HIGH COUNTRY. LASTLY...SEE LITTLE DAY-TO-DAY CHANGE IN TEMPERATURE
THROUGH THE EXTENDED PERIOD.
AVIATION...LIGHT WINDS...LESS THAN 12 KNOTS...WILL PREVAIL THIS
MORNING AND THIS AFTERNOON. EXPECT WINDS TO BECOME
NORTHERLY...AROUND 21Z...BUT WIND SPEEDS WILL REMAIN LIGHT. MID
AND HIGH CLOUDS WILL INCREASE AFTER 18Z AS NEXT WEATHER SYSTEM
PASSES SOUTH OF COLORADO. A SLIGHT CHANCE WE COULD SEE A SHORT-
LIVED SNOW SHOWER 00-09Z...ANY SNOW ACCUMULATION WILL BE VERY
LIGHT. MODELS SHOWING LOW CLOUDS OVER THE EASTERN PLAINS WEDNESDAY
MORNING AND THERE IS A CHANCE THEY COULD MAKE IT AS FAR WEST AS
KDEN.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
637 AM EST TUE FEB 14 2012
...PATCHES OF LIGHT SLEET FALLING INLAND THIS MORNING...
.SYNOPSIS...
A WEAK WAVE OF LOW PRESSURE WILL MOVE ACROSS THE GULF COAST TODAY.
A COLD FRONT WILL PUSH OFFSHORE TONIGHT. ANOTHER COLD FRONT WILL
MOVE ACROSS THE EAST COAST THURSDAY AND LINGER TO THE SOUTH
THROUGH THE WEEKEND. A LOW PRESSURE SYSTEM COULD DEVELOP
ACROSS THE GULF OF MEXICO AND IMPACT THE FORECAST AREA EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STARTING TO RECEIVE SOME REPORTS OF LIGHT SLEET ACROSS INTERIOR
SOUTHEAST GEORGIA AND THE CSRA. RUC SOUNDINGS STILL SUPPORT
OCCASIONAL PHASE CHANGES TO SLEET WHERE POCKETS OF HEAVIER SHOWERS
ARE ABLE TO MAXIMIZE DIABATIC EFFECTS. REFLECTIVITY RETURNS OF 40+
DBZ APPEARS TO BE THE THRESHOLD FOR SLEET ON THE KCLX RADAR. THE
GREATEST RISK FOR SLEET WILL CONTINUE TO BE CENTERED ACROSS
INTERIOR SOUTHEAST GEORGIA...BUT WOULD NOT BE SURPRISED TO SEE
A FEW SLEET PELLETS MIX IN AS FAR EAST AS WALTERBORO...BEAUFORT
AND SAVANNAH. NO IMPACTS ARE EXPECTED. OTHERWISE...ITS LOOKING
LESS AND LESS LIKELY THAT MEASURABLE RAINS WILL FALL IN THE
CHARLESTON TRI-COUNTY AREA. OPTED NOT TO MODIFY POPS JUST
YET...BUT CURRENT TRENDS ARE CONCERNING. REGIONAL RADARS
CERTAINLY LOOK WORSE THAN WHAT IS OCCURRING AT THE SURFACE.
A BROAD WARM AIR ADVECTION REGIME IS TAKING SHAPE ACROSS THE
SOUTHEAST U.S. THIS MORNING AS WEAK LOW PRESSURE MEANDERS EAST
ALONG THE NORTHERN GULF COAST. INFRARED SATELLITE IMAGERY SHOWS
CLOUD TOPS SLOWLY COOLING ACROSS CENTRAL GEORGIA AS SHORTWAVE
ENERGY APPROACHES THE SOUTHERN APPALACHIANS. RAIN CHANCES WILL
STEADILY INCREASE ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST
GEORGIA AFTER SUNRISE AS THE CORE OF THE STRONGEST WARM AIR
ADVECTION TRAVERSES FROM WEST-EAST THIS MORNING. MODELS ARE IN
FAIR AGREEMENT IN THE PLACEMENT OF THE HIGHEST POPS TODAY WITH
MOST MEMBERS CLUSTERING THE HIGHEST PROBABILITIES ROUGHLY ALONG
THE SAVANNAH RIVER FROM MID-LATE MORNING INTO THE EARLY AFTERNOON
HOURS.
RAINFALL WILL GENERALLY BE LIGHT TODAY WITH FORECAST SOUNDINGS
DEPICTING A RATHER PARCHED SUB-CLOUD LAYER HOLDING FOR MUCH OF
THE DAY. THIS WILL LIMIT POTENTIAL RAINFALL AMOUNTS TO ROUGHLY
1/10TH INCH OR LESS FOR MANY LOCATIONS AND THERE ARE EVEN SOME
INDICATIONS IN THE HIGHER RESOLUTION DATA SETS THAT MUCH OF THE
CHARLESTON TRI-COUNTY COULD RECEIVE LITTLE IF ANY RAINFALL FROM
THIS EVENT. THIS IS UNFORTUNATE GIVEN THE EXPANDING EXCEPTIONAL
DROUGHT CONDITIONS. PLAN TO LIMIT POPS TO 40-60 PERCENT TODAY WITH
THE HIGHEST GRIDDED POPS CONFINED IN A RATHER BROAD CORRIDOR FROM
MILLEN AND METTER EAST TO BEAUFORT...SAVANNAH AND HINESVILLE. THE
LOWEST POPS /40-50 PERCENT/ WILL BE PLACED ACROSS THE CHARLESTON
TRI-COUNTY AREA. SOME ADJUSTMENTS WILL MOST CERTAINLY BE NEEDED AS
THE DAY PROGRESSES.
TEMPERATURES ACROSS THE REGION EARLY THIS MORNING HAVE DROPPED
INTO THE MID-UPPER 30S WITH A FEW LOWER NOTED IN A FEW OF THE
NORMALLY COLDER LOCATIONS. TEMPERATURES WILL LIKELY FLUCTUATE SOME
OVER THE NEXT SEVERAL HOURS AS CLOUD LAYERS THICKEN/LOWER AND
LIGHT PRECIPITATION BEGINS TO INITIATE DIABATIC COOLING. FORECAST
SOUNDINGS ACROSS THE FAR WESTERN ZONES STILL SUGGEST THERE WILL BE
ABOUT A 3-4 HOUR WINDOW FOR SOME LIGHT SLEET TO MIX IN WITH THE
RAIN AT TIMES. HAVE ALREADY SEEN SEVERAL REPORTS OF LIGHT SLEET
ACROSS CENTRAL GEORGIA OVER THE PAST FEW HOURS WITH THE MOST
RECENT REPORT COMING OUT OF THE WARNER ROBBINS AREA. DUAL-POL
DATA FROM THE RECENTLY UPGRADED KFFC RADAR HAS BEEN MOST USEFUL IN
HELPING TO VERIFY P-TYPE TRENDS EARLY THIS MORNING WITH SLEET
REPORTS LINING UP NICELY WITH THE HYBRID HYDROMETER CLASSIFICATION
PRODUCT. WILL CONTINUE TO HIGHLIGHT A CHANCE OF SLEET ROUGHLY
ALONG AND WEST OF A HAMPTON-SPRINGFIELD-CLAXTON-REIDSVILLE LINE
THROUGH MID-MORNING. VERY LITTLE OR NO ACCUMULATION OF SLEET IS
EXPECTED GIVEN THE EXPECTED VERY LIGHT PRECIPITATION
RATES...HOWEVER WE MAY CONSIDER ISSUING A SPECIAL WEATHER
STATEMENT SINCE THE SLEET WILL LIKELY BE FALLING DURING THE
MORNING COMMUTE. ITS IMPORTANT TO STRESS THAT THIS WILL BE A NON-
EVENT.
EXTENSIVE CLOUD COVER COUPLED WITH ONGOING VERY LIGHT RAIN WILL
LIMIT HIGHS TO THE 50S FOR MOST PLACED WITH THE POTENTIAL FOR A
FEW LOWER 60S NEAR THE DARIEN AND LUDOWICI AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RAIN CHANCES WILL GRADUALLY DIMINISH THIS EVENING AS A COLD FRONT
APPROACHES FROM THE WEST AND THE CORRIDOR OF STRONGEST WARM AIR
ADVECTION SHIFTS WELL OFFSHORE. SHOWERS MAY LINGER NEAR THE
ALTAMAHA RIVER THROUGH ABOUT MIDNIGHT...BUT SHOULD STEADILY
DIMINISH THEREAFTER. GUIDANCE AND SOME SREF MEMBERS SUGGEST LOW
CLOUDS WILL FILL IN FROM THE WEST OVERNIGHT WITH MARGINALLY WET
GROUNDS AND LIGHT WINDS IN PLACE. LOW CONFIDENCE ON EXACTLY HOW
THIS SCENARIO WILL PLAY OUT...ESPECIALLY AS LOW-LEVEL WINDS BECOME
MORE DOWNSLOPE DOMINATE IN THE WAKE OF THE FRONT AFTER MIDNIGHT.
WILL SHOW MOSTLY CLOUDY SKIES WITH SOME CLEARING ACROSS THE
WESTERN ZONES LATE...BUT FURTHER ADJUSTMENTS WILL BE NEEDED LATER
TODAY. LOWS WILL RANGE FROM THE UPPER 30 WELL INLAND TO THE UPPER
40S/LOWER 50S AT THE BEACHES.
TRANSIENT SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL
SUPPORT WARMER TEMPERATURES AND DRY CONDITIONS FOR THE DAYTIME AND
EVENING HOURS WEDNESDAY. HIGH TEMPERATURES WILL REACH THE UPPER
60S TO THE LOWER 70S UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
SHORTWAVE ENERGY WILL RAPIDLY APPROACH WEDNESDAY NIGHT AND BREAK
DOWN THE WESTERN PERIPHERY OF THE UPPER RIDGE. A WARM FRONTAL
FEATURE WILL BE LIFTING NORTH ACROSS THE FORECAST AREA AFTER
MIDNIGHT...AHEAD OF THE COLD FRONT SHIFTING INTO THE SOUTHEAST
STATES BY THURSDAY. THICKENING CLOUD COVER WEDNESDAY NIGHT WILL
SUPPORT MILDER LOW TEMPERATURES IN THE UPPER 40S TO LOW 50S.
ENHANCED MOISTURE CONVERGENCE AND ASCENT WITHIN THE WARM
FRONT...AS WELL AS INCREASING UPPER LEVEL SUPPORT...SUGGESTS THAT
ISOLATED SHOWERS COULD OCCUR AFTER MIDNIGHT EARLY THURSDAY MORNING
FOR MAINLY THE WESTERN HALF OF THE FORECAST AREA.
GIVEN DECENT MODEL CONSENSUS THAT THE APPROACHING COLD FRONT WILL
HAVE A SUFFICIENT TAP INTO GULF MOISTURE...WILL MAINTAIN SOLID
RAIN CHANCES IN THE 30 TO 40 PERCENT RANGE DURING THE DAYTIME
HOURS ON THURSDAY. SOUTHERLY FLOW WITHIN THE WARM SECTOR OF THE
SYSTEM WILL ALLOW TEMPERATURES TO RISE WELL ABOVE NORMAL...PEAKING
IN THE THE UPPER 60S INLAND SOUTH CAROLINA TO THE LOWER 70S NEAR
THE ALTAMAHA IN SOUTHEAST GEORGIA. THE COLD FRONT WILL STEADILY
SHIFT THROUGH THE FORECAST AREA THURSDAY EVENING...FOLLOWING THE
SHORTWAVE ENERGY INTO THE ATLANTIC. HAVE THUS INDICATED DECREASING
RAIN CHANCES FROM WEST TO EAST OVERNIGHT. SINCE THE FRONT WILL LIKELY
CROSS THE COASTLINE AS LATE AS DAYBREAK FRIDAY...LOW TEMPERATURES
WILL BE QUITE MILD DUE TO THE INSULATING EFFECTS OF LINGERING
CLOUDS AND MORE PERSISTENT SOUTHERLY FLOW FOR THE MAJORITY OF
THURSDAY NIGHT.
THE COLD FRONT WILL DESCEND SOUTHEAST AND OFFSHORE ON
FRIDAY...BECOMING NEARLY PARALLEL TO ZONAL FLOW ALOFT. SURFACE
HIGH PRESSURE WILL SHIFT ACROSS THE MID ATLANTIC AND SOUTHEAST
STATES...SUPPRESSING MOST OF THE DEEP MOISTURE TO THE SOUTH OF THE
FORECAST AREA WITH THE LINGERING FRONT. WILL THUS KEEP RAIN
CHANCES BELOW 15 PERCENT ON FRIDAY. LITTLE TO NO COLD ADVECTION
BEHIND THE FRONT SUGGESTS ONLY A SLIGHT DECREASE IN TEMPERATURES FOR
FRIDAY...GENERALLY RANGING FROM 68 TO 72 DEGREES DURING THE
AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THERE REMAINS QUITE A BIT OF UNCERTAINTY IN THE EXTENDED
PERIOD...AS MUCH OF THE FORECAST DETAILS WILL BE HIGHLY DEPENDENT
ON THE EVOLUTION OF THE LINGERING COLD FRONT TO THE SOUTH AND A
POTENTIALLY STRONG GULF LOW SYSTEM DEVELOPING LATE IN THE
WEEKEND. LATEST MODEL SOLUTIONS SHOW GENERAL AGREEMENT THAT THE
LINGERING BOUNDARY COULD LIFT NORTHWARD AS A WARM FRONT ON
SATURDAY...WHILE A STRONG SHORTWAVE ASSISTS IN THE DEVELOPMENT OF
A LOW SYSTEM IN THE GULF OF MEXICO. THIS SYSTEM COULD TRACK
EAST/NORTHEAST ACROSS THE GULF COAST STATES AND TOWARD THE
FORECAST AREA LATE SATURDAY INTO SUNDAY...LIFTING INTO THE
ATLANTIC BY MONDAY. SIGNIFICANT MODEL SOLUTION DIFFERENCES IN THE
TRACK AND STRENGTH OF THIS LOW SYSTEM LENDS LITTLE
CONFIDENCE...AND PREFER TO REMAIN RATHER GENERIC WITH POPS AND
TEMPERATURES FOR THE WEEKEND AND INTO EARLY NEXT WEEK.
WILL REINTRODUCE PRECIPITATION FROM THE SOUTH WITH THE LIFTING
WARM FRONT ON SATURDAY...WITH BEST RAIN CHANCES LATER SATURDAY
INTO EARLY SUNDAY WHEN THE SYSTEM COULD BE IMPACTING THE SOUTHEAST
STATES. HAVE THEN INDICATED POPS FALLING BELOW 15 PERCENT LATE
SUNDAY INTO EARLY NEXT WEEK...AS HIGH PRESSURE FOLLOWS IN THE WAKE
OF THE SYSTEM.
TEMPERATURES WILL BE DICTATED BY THE TIMING AND EFFECTS OF THE LOW
PRESSURE SYSTEM AND ASSOCIATED FRONTS THROUGH THE WEEKEND. WILL
MENTION HIGH TEMPERATURES GENERALLY IN THE 60S SUNDAY THROUGH
TUESDAY...HOWEVER THIS FORECAST WILL LIKELY BE MODIFIED QUITE A
BIT DEPENDING ON THE TRACK OF THE SURFACE LOW.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
KCHS...MAINLY VFR THROUGH SUNSET WITH A POTENTIAL FOR IFR OR MVFR
CIGS OVERNIGHT IN THE WAKE OF A COLD FRONT. LIGHT PCPN EXPECTED TO
REMAIN SOUTH OF KCHS CLOSER TO THE KNBC-KSAV-KLHW CORRIDOR.
CONFIDENCE FOR LOW CIGS TONIGHT IS LOW AS FORECAST SOUNDING SHOW
ONLY A THIN RIBBON OF MOISTURE LINGERING AFTER SUNSET. TABULAR
GUIDANCE HINTING AT A WINDOW OF 09-12Z FOR TIME FOR IFR
CONDITIONS. SINCE THIS IS AT THE END OF THE 12Z TAF PERIOD OPTED
TO CAP CIGS AT MVFR FOR NOW.
KSAV...LIGHT RAIN IS EXPECTED TO SPREAD INTO THE TERMINAL SHORTLY.
THE RAIN WILL BE RATHER LIGHT IN INTENSITY BUT MAY PRODUCE A FEW
HOURS OF HIGH-END MVFR CIGS/VSBYS ROUGHLY 16-19Z. A FEW SLEET
PELLETS MAY ALSO MIX IN AT TIMES AT THE ONSET. SHOWER ACTIVITY
EXPECTED TO PUSH SOUTH AND SOUTHEAST OF THE TERMINAL DURING THE
AFTERNOON. THERE IS A POTENTIAL FOR MVFR OR IFR CIGS DEVELOPING
TONIGHT IN THE WAKE OF A COLD FRONT. CONFIDENCE FOR LOW CIGS
TONIGHT IS LOW AS FORECAST SOUNDING SHOW ONLY A THIN RIBBON OF
MOISTURE LINGERING AFTER SUNSET. TABULAR GUIDANCE HINTING AT A
WINDOW OF 06-12Z FOR TIME OF MVFR-IFR CONDITIONS. WILL CAP CIGS AT
MVFR FOR NOW UNTIL CONFIDENCE INCREASES.
EXTENDED AVIATION OUTLOOK...REDUCED CEILINGS/VISIBILITIES ARE
POSSIBLE LATE THURSDAY AS A COLD FRONT MOVES THROUGH THE AREA.
&&
.MARINE...
A VERY LIGHT WIND REGIME WILL DOMINATE ACROSS THE WATERS THROUGH
TONIGHT. SEAS WILL REMAIN GENERALLY 2 FT OR LESS.
WEDNESDAY THROUGH SATURDAY...MARINE CONDITIONS ARE EXPECTED TO
REMAIN BELOW ADVISORY LEVELS THROUGH MID WEEK AS HIGH PRESSURE
MOVES ACROSS THE AREA. A SURGE IN SOUTHERLY FLOW WILL OCCUR AHEAD
OF THE NEXT COLD FRONT CROSSING THE COASTLINE ON THURSDAY.
HOWEVER...THE WARM ADVECTION REGIME ON THURSDAY AND LACK OF STRONG
COLD ADVECTION BEHIND THE SYSTEM SUGGEST THAT CONDITIONS WILL
STILL REMAIN BELOW ADVISORY CRITERIA.
THERE IS A LOT OF FORECAST UNCERTAINTY OVER THE WEEKEND...AS THE
FRONT LINGERS TO THE SOUTH AND A GULF OF MEXICO LOW SYSTEM
DEVELOPS. WILL INDICATE INCREASING NORTH/NORTHEAST FLOW BEHIND THE
COLD FRONT BY SATURDAY...WHILE KEEPING CONDITIONS JUST BELOW
ADVISORY THRESHOLDS AT THIS TIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
824 PM CST WED FEB 15 2012
.DISCUSSION...
823 PM CST
THERE WERE SOME SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST BUT
THE GENERAL THEME OF A WET NIGHT WITH TEMPERATURES DROPPING AT A
SNAILS PACE STILL LOOKS GOOD.
AFTER SOME DRIER AIR ALOFT AND LIMITED FOCUS...RAIN HAS SPREAD
OVER A LARGE PORTION OF THE AREA THIS EVENING. THIS APPEARS TO BE
THANKS IN PART TO A LEAD SHORT WAVE PER WV/PROFILER ANALYSIS AND
ASSOCIATED BETTER 850-700MB CONVERGENCE THAT LINES UP WELL WITH
RADAR RETURNS. GIVEN THE RUC ANALYSIS OF THIS FIELD...TRENDS ON
RADAR...AND HIGH AVAILABLE MOISTURE /BASICALLY 200 PERCENT OF
NORMAL PWATS ON DVN AND ILX RAOBS/...THE RAIN AXIS SHOULD
CONTINUE FOR SEVERAL HOURS WHILE GRADUALLY EXPANDING/EVOLVING
SOUTHEAST AS FORCING FROM THE MAIN UPPER LOW APPROACHES. THIS WAVE
STILL HAS A CLOSED CIRCULATION ON WATER VAPOR AND IS TRIGGERING
CONVECTION ACROSS WESTERN MO. BUT THIS IS FORECAST TO DAMPEN IN
THE MORE CONFLUENT FLOW...LIMITING MORE INTENSE FORCING AND
DYNAMIC COOLING EFFECTS. SO WITH MORE LIMITED FORCING HAVE ADDED
DRIZZLE AND FOG MENTION IN THE FORECAST...ESPECIALLY OVERNIGHT.
THE LOW T/TD SPREADS AND DECREASING FLOW WITH THE BAGGY SURFACE
TROUGH MOVING ACROSS SHOULD FURTHER AID IN SOME AREAS OF LIGHT
FOG.
IT STILL IS POSSIBLE TO HAVE SOME WET NON-ACCUMULATING SNOW
TOWARDS THE NORTHWEST FORECAST AREA LATE TONIGHT AND MAYBE A BRIEF
MIX TOWARDS CHICAGO AS THE SYSTEM DEPARTS THU MORNING. WHILE THE
DVN RAOB DID COME IN AROUND 1-2C COOLER IN THE LOWER PROFILE THAN
THE 00Z RUC AND 18Z NAM...IT STILL DEPICTED NEARLY A 4500 FT THICK
LAYER NEAR OR ABOVE FREEZING. IN THE ABSENCE OF STRONG COLD AIR
ADVECTION...A DECREASING CHANCE FOR SNOW IN THE FORECAST
CONTINUES. AS FOR THUNDER...SOME WEAK POSITIVE INSTABILITY IS
PRESENT ON THE ILX SOUNDING WHEN LIFTING PARCELS FROM 850 MB...BUT
THE BETTER ELEVATED INSTABILITY GRADIENT WHICH LINES UP WITH
ONGOING CONVECTION IN MO LOOKS TO STAY TO OUR SOUTH. POCKETS OF
ISOLATED HEAVIER RAIN HAVE BEEN SEEN PER DUAL-POL ANALYSIS. GOING
QPF FORECAST LOOKS ALRIGHT ON MAGNITUDE...BUT DID SHRINK THE AREAL
COVERAGE OF THE FORECAST ONE QUARTER OF AN INCH AND GREATER.
MTF
&&
.PREV DISCUSSION...
317 PM...PRIMARY FORECAST FOCUS REMAINS APPROACHING SYSTEM WITH
MAINLY RAIN/SHOWERS TONIGHT.
AFTER A BRIEF PERIOD OF SOME SUN THIS MORNING...LOW CLOUDS SPREAD
NORTH AND DEVELOPED ACROSS THE AREA ALONG WITH SOME SHOWERS MIDDAY
WHICH HAVE SINCE MOVED OVER THE LAKE. FAIRLY STRONG UPPER WAVE TO
MOVE ACROSS THE AREA TONIGHT...THOUGH IT SLOWLY WEAKENS WITH TIME.
SCATTERED SHOWERS CURRENTLY DEVELOPING FROM KANSAS INTO SOUTHERN
IOWA AND THIS ACTIVITY WILL CONTINUE NORTHEAST ACROSS THE AREA
THIS EVENING INTO EARLY THURSDAY MORNING. LATEST GUIDANCE
SUGGESTS A TREND OF THE HEAVIEST RAIN...OR THE POTENTIAL FOR THE
HEAVIEST RAIN...FALLING ACROSS THE SOUTHERN CWA AND POINTS SOUTH
AND EAST. SO HAVE BACKED OFF ON QPF AMOUNTS SOME ESPECIALLY NORTH
WITH STRONGER CONVECTION FURTHER SOUTH TAKING SOME OF THE
AVAILABLE MOISTURE/QPF. THOUGH SINCE THERE COULD STILL BE SOME
CONVECTIVE ELEMENTS...LOCALIZED RAINFALL TOTALS OF A HALF TO THREE
QUARTERS OF AN INCH ARE STILL POSSIBLE. THERE IS ALSO SOME SMALL
INSTABILITY ALOFT THAT MAY CAUSE A RUMBLE OR TWO OF THUNDER...
MAINLY ACROSS THE FAR SOUTHERN CWA AND WILL CONTINUE WITH NO
MENTION OF THUNDER.
AS FOR ANY SNOW POTENTIAL...NOT MUCH COLD AIR TO WORK WITH THIS
SYSTEM AND DEW POINTS ALREADY CREEPING UP INTO THE MID 30S ACROSS
NORTHERN IL. ANY SNOW WOULD LIKELY RESULT FROM PRECIP COOLING THE
COLUMN ON THE BACK SIDE OF THE PRECIP LATE TONIGHT INTO EARLY
THURSDAY MORNING...RATHER THAN SHARP COLD AIR ADVECTION. AND BY
THE TIME THERE IS ENOUGH COLD AIR FOR PRECIP TO CHANGEOVER TO
SNOW...IT APPEARS PRECIP WILL BE ENDING. THUS HAVE MAINTAINED A
CHANCE OF SNOW ACROSS THE FAR NORTHWEST CWA OVERNIGHT AND THEN A
CHANCE OF RAIN OR SNOW SHOWERS MIXED THURSDAY MORNING...BUT EVEN
IF PRECIP WERE TO GO OVER TO SNOW...GROUND WOULD LIKELY BE WARM
ENOUGH AND WET ENOUGH THAT LITTLE OR NO ACCUMULATION WOULD RESULT.
AND AS NOTED...HUNG ONTO SLIGHT/CHANCE POPS THURSDAY MORNING BUT
ITS ALSO POSSIBLE THAT PRECIP MAY END BY SUNRISE MOST AREAS. IN
ADDITION...IF HEAVIER RAIN/SHOWERS DO END UP FURTHER SOUTH...
PRECIP MIGHT END UP BEING MORE DRIZZLE.
TEMPERATURES CURRENTLY IN THE LOWER 40S WILL SLOWLY FALL INTO THE
MID/UPPER 30S BUT FOR THE MOST PART WILL BE STEADY...PROBABLY NOT
DROPPING SIGNIFICANTLY UNTIL WIDESPREAD PRECIP BEGINS FALLING.
LOWS ACROSS THE NORTHWEST MAY DIP DOWN TO FREEZING BY MORNING BUT
MOST OF THE CWA LIKELY TO STAY JUST ABOVE FREEZING THROUGH
MORNING. CLOUDS BEGIN CLEARING BY LATE THURSDAY MORNING AND WITH
SOME SUN IN THE AFTERNOON...SHOULD SEE TEMPS WARM INTO THE LOWER
40S THURSDAY.
A RIDGE OF HIGH PRESSURE SLIDES BY THURSDAY NIGHT INTO FRIDAY WITH
SOUTHERLY FLOW RETURNING FRIDAY AFTERNOON. DEPENDING ON THE EXTENT
OF INCREASING CLOUDS FRIDAY AFTERNOON...TEMPS WARMING BACK INTO
THE MID/UPPER 40S SEEMS REASONABLE FROM THIS DISTANCE. MODELS THEN
BRING ACROSS ANOTHER WEAK SURFACE LOW FRIDAY NIGHT. APPEARS THE
BULK OF THE PRECIP WITH THIS SYSTEM WILL REMAIN ON THE NORTH SIDE
OF THIS LOW AND NORTH OF THE CWA...BUT A FEW RAIN OR SNOW SHOWERS
APPEAR POSSIBLE ALONG THE TRAILING COLD FRONT LATE FRIDAY NIGHT
INTO SATURDAY MORNING AND INTRODUCED LOW CHANCE POPS DURING THIS
TIME PERIOD. THIS COLD FRONT USHERS IN SOME COLDER AIR...THOUGH
THE MODELS DIFFER ON THE EXTENT OF JUST HOW COLD THIS AIR WILL
BE. DOESN/T APPEAR TOO COLD BUT HIGHS THIS WEEKEND LIKELY ONLY IN
THE 30S.
NEXT WEEK LOOKING BOTH UNSETTLED AND UNCERTAIN AS A POSSIBLE COLD
FRONT MOVES THROUGH THE AREA TUESDAY WITH A STRONGER SYSTEM
LIFTING NORTHEAST ACROSS THE OHIO VALLEY/SOUTHERN LAKES REGION
TOWARD MIDWEEK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 02Z...
* IFR/LIFR CEILINGS AND VISIBILITIES TONIGHT.
* ENDING TIME OF -RA AND POTENTIAL FOR -DZ OVERNIGHT.
TRS
//DISCUSSION...UPDATED 00Z...
SYSTEM MOVING FROM THE PLAINS OVER THE MIDWEST IS RATHER
DISORGANIZED BASED ON CLOUD TOP TEMPS SEEN IR SATELLITE AND ON
RADAR LOOPS. EVEN THOUGH A WELL DEFINED UPPER LOW IS SEEN OVER
EASTERN KS THERE APPEARS TO BE MULTIPLE SMALLER SCALE IMPULSES
EMBEDDED WITHIN THE OVERALL LARGE SCALE FLOW.
LATEST MODEL GUIDANCE INDICATING THAT MAIN RAIN AREA WILL REMAIN
TO THE SW THROUGH S AND E OF THE LOCAL TERMINALS TONIGHT WHERE
BEST FORCING MAXIMIZED AHEAD OF THE UPPER TROUGH PROGGED TO REACH
THE IL-IN BORDER BY 12Z THU. HOWEVER...STILL EXPECT A PERIOD OR
PERIODS OF RAIN THIS EVENING AND INTO THE OVERNIGHT AS MID AND
UPPER LEVEL ASCENT MOVES OVER THE LOCAL AREA.
AN AREA OF RAIN HAS BEEN GRADUALLY MOVING ENE FROM SE IA TO N
CENTRAL IL OVER THE LAST FEW HOURS THOUGH LEADING EDGE APPEARED
TO BE DISSIPATING THE FURTHER E IT GOT INTO IL. MEASUREMENT OF
MOISTURE FROM AN AIRCRAFT DESCENT INTO MDW AT 2132Z SHOWED A DRY
LAYER FROM 800 TO 700 HPA WHICH WAS LEADING TO THE DELAYED
EASTWARD PROGRESS OF THIS LEADING EDGE AS COMPARED EARLIER
ARRIVAL USING EXTRAPOLATION OF RADAR ECHOES. LATEST FRAMES OF
RADAR LOOP SHOWING THE RAIN RECENTLY MAKING STEADY PROGRESS
ACROSS N CENTRAL IL AS THE DRY LAYER HAS BECOME SATURATED.
MEANWHILE...AS S TO SSE LOW LEVEL FLOW CONTINUED TO ADVECT MID
AND UPPER 30S F DEW POINTS INTO THE AREA CEILINGS JUST S OF MDW
AND ORD HAD FALLEN TO BELOW 010 AND VISIBILITIES TO GENERALLY 3 TO
5 SM. THESE CONDITIONS ARE EXPECTED TO CONTINUE TO SPREAD
NORTHWARDS ACROSS FAR NE IL EARLY THIS EVENING EVEN THOUGH THE LOW
LEVEL FLOW IS PROGGED TO WEAKEN WITH TIME AS A WEAK SURFACE LOW OR
TROUGH MOVES E ACROSS THE MS RIVER DURING THE EARLY AND MID
EVENING.
ANY LARGER SCALE LIFT IS PROGGED TO BE E OF THE LOCAL AREA BY
AROUND 09Z BUT MID AND LOWER LEVELS REMAIN SATURATED UNTIL AROUND
12Z SO ANTICIPATE IFR CEILINGS TO PERSIST THROUGH THE NIGHT WITH
OCCASIONAL DRIZZLE DURING THE LATE NIGHT AND PRE DAWN HOURS. BY
DAYBREAK A DRYING NW LOW LEVEL FLOW IS TO HAVE BECOME ESTABLISHED
IN THE WAKE OF THE SURFACE...MID AND UPPER LEVEL TROUGHS. MODEL
GUIDANCE SHOWS QUICK CLEARING OUT OF THE REMAINING LOW LEVEL
MOISTURE BY MIDDAY THU SO EXPECT A QUICK JUMP FROM IFR CEILINGS
TO PRETTY MUCH SKC THEN.
A FAIRLY STRONG SURFACE RIDGE IS TO BE BUILDING SE ACROSS THE
PLAINS LATE TONIGHT AND DURING THU RESULTING A MODERATELY STRONG
WNW-NW LOW LEVEL FLOW OVER THE LOCAL AREA BY THE TIME THE CLOUDS
CLEAR OUT. WITH SURFACE HEATING MIXED LAYER PROGGED TO DEEPEN TO
1-1.5KM WHICH WOULD ALLOW MOMENTUM TRANSFER OF 20-25KT WINDS AT
THIS LEVEL MIXING DOWN TO THE SURFACE RESULTING IN SOME GUSTINESS
FROM MIDDAY UNTIL SUNSET THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 02Z...
* HIGH CONFIDENCE IN IFR TONIGHT.
* HIGH CONFIDENCE IN LIGHT WINDS THROUGH THE NIGHT.
* MODERATE CONFIDENCE IN ENDING TIME OF -RA AND IN OCCURRENCE OF
-DZ OVERNIGHT INTO PRE-DAWN.
* MODERATE CONFIDENCE IN RAPID IMPROVEMENT FROM IFR DURING LATER
THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR.
SATURDAY...POSSIBLE MVFR CIGS.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...CHANCE RA AND/OR SN WITH MVFR.
TRS
&&
.MARINE...
203 PM CST
MAIN MARINE FORECAST CONCERNS ARE THE POTENTIAL FOR A COUPLE OF
PERIODS OF 20-25 KT WINDS OVER THE NEXT FEW DAYS...THURSDAY INTO
THURSDAY NIGHT AND AGAIN SATURDAY INTO SATURDAY NIGHT.
LOW PRESSURE WAS OVER THE SOUTHERN PLAINS OF OKLAHOMA THIS
AFTERNOON...WITH A WEAKER TROUGH EXTENDING THROUGH THE UPPER MIDWEST
TO ANOTHER LOW OVER ONTARIO. THE PLAINS LOW WILL WEAKEN AS IT MOVES
EAST ACROSS ILLINOIS AND INDIANA INTO SOUTHWESTERN LOWER MICHIGAN BY
THURSDAY MORNING...THEN WILL COMBINE WITH THE ONTARIO LOW AS THEY
MOVE EAST OF THE LAKES...EVENTUALLY DEEPENING OVER SOUTHWEST QUEBEC
BY THURSDAY EVENING. ONCE THE LOW AND TROUGH AXIS MOVE ACROSS LAKE
MICHIGAN TONIGHT...WINDS WILL SHIFT TO THE WEST AND INCREASE INTO
THE 15 TO 25 KT RANGE THURSDAY AS THE LOW DEEPENS OFF TO THE EAST.
WINDS WILL GRADUALLY DIMINISH THURSDAY NIGHT...AS HIGH PRESSURE
SLIDES INTO THE LOWER OHIO VALLEY AND WEAKER RIDGING EXTENDS NORTH
INTO THE WESTERN LAKES FRIDAY MORNING. ANOTHER WEAK LOW WILL FOLLOW
ACROSS LAKE MICHIGAN LATE FRIDAY NIGHT AND SATURDAY...WITH NORTHERLY
WINDS PICKING UP AGAIN INTO THE 15 TO 25 KT RANGE SATURDAY AND
SATURDAY NIGHT AS THE GRADIENT TIGHTENS FOR A TIME BETWEEN THE
DEPARTING LOW TO THE EAST AND HIGH PRESSURE SPREADING ACROSS THE
UPPER MIDWEST. THIS HIGH WILL SLOWLY SPREAD EAST ACROSS THE LOWER
OHIO VALLEY AND WESTERN LAKES BY SUNDAY NIGHT...ALLOWING WINDS TO
DIMINISH AHEAD OF THE RIDGE ON SUNDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
0933 PM EST WED FEB 15 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE OHIO VALLEY TONIGHT...BRINGING
WIDESPREAD RAIN AND PERHAPS A COUPLE THUNDERSTORMS FOR CENTRAL
INDIANA. CHANCES FOR RAIN WILL END BY MIDDAY THURSDAY AS THE LOW
PULLS AWAY TO THE EAST. HIGH PRESSURE WILL EXPAND INTO THE REGION BY
THURSDAY NIGHT...WITH DRY WEATHER AND SEASONABLE TEMPERATURES
EXPECTED THROUGH THE WEEKEND. PRECIP CHANCES WILL RETURN FOR NEXT
TUESDAY AND WEDNESDAY AS A COLD FRONT MOVES THROUGH THE REGION.
&&
.NEAR TERM /TONIGHT/...
LIGHT RAINFALL CONTINUES TO EXPAND ACROSS CENTRAL INDIANA THIS
AFTERNOON AHEAD OF A FRONTAL BOUNDARY MOVING APPROACHING FROM THE
WEST. TEMPS HAD WARMED INTO THE MID 40S OVER EASTERN PORTIONS OF THE
FORECAST AREA WHERE PRECIP WAS JUST BEGINNING TO ARRIVE. FURTHER
WEST AS RAINFALL BEGINS...TEMPS SLIDING BACK A FEW DEGREES INTO THE
LOWER 40S.
FORECAST FOCUS TONIGHT IS ON RAIN CHANCES AS FRONTAL BOUNDARY
ARRIVES AND A SURFACE WAVE TRACKS THROUGH THE REGION. HAVE RELIED
MORE ON THE HRRR FOR RAINFALL COVERAGE INTO THIS EVENING AS BOTH THE
NAM AND OP GFS ALREADY ARE TOO FAR NORTH AND NOT CAPTURING THE
WIDESPREAD NATURE OF THE LIGHT PRECIP PROPERLY.
BROAD SURFACE WAVE CURRENTLY LOCATED OVER OKLAHOMA WILL MOVE
STEADILY NORTHEAST INTO THE OHIO VALLEY OVERNIGHT. WHILE PRECIP WILL
REMAIN LIGHT OVER THE NEXT FEW HOURS...RAINFALL INTENSITY SHOULD
INCREASE DURING THE EVENING AS 35-40KT LOW LEVEL JET PUMPS DEEPER
MOISTURE INTO THE REGION AHEAD OF THE APPROACHING WAVE. BOTH OP GFS
AND NAM INDICATE FAVORABLE PRECIP EFFICIENCY PROGS AFTER MIDNIGHT AS
LOW LEVEL CONVERGENCE BELOW 700MB MAXIMIZES AND COINCIDES WITH AN
AXIS OF PRECIP WATER VALUES APPROACHING 1 INCH. ENHANCED FORCING
ALOFT WILL ALSO CONTRIBUTE TO WIDESPREAD RAINFALL WITH EMBEDDED
CONVECTIVE ELEMENTS OVERNIGHT. HAVE CONTINUED WITH 100 POPS FOR THE
ENTIRE FORECAST AREA...SPECIFICALLY FOCUSED AFTER MIDNIGHT WHEN
FORCING AND MOISTURE ARE GREATEST. MODEL SOUNDINGS SHOWING WEAK
ELEVATED INSTABILITY WHICH MAY BE ENOUGH TO GENERATE A FEW
THUNDERSTORMS OVER THE AREA LATE TONIGHT AS THE BOUNDARY APPROACHES
AND WILL CONTINUE TO CARRY SLIGHT CHANCES FOR THUNDER. QPF VALUES OF
0.40 TO 0.75 INCHES STILL LOOKS QUITE REASONABLE BY DAYBREAK
THURSDAY.
TEMPS...TEMPS NOT LIKELY TO FALL MUCH OVERNIGHT AS COOLER AIR REALLY
DOES NOT START TO WORK INTO THE REGION UNTIL RIGHT NEAR DAYBREAK AS
THE FRONT SWEEPS THROUGH THE AREA. LAMP DATA DOING A MUCH BETTER JOB
THAN MOS CAPTURING THIS THINKING...AND HAVE LEANED MUCH CLOSER TO
ITS NUMBERS WITH LOWS RANGING FROM THE UPPER 30S NORTH TO NEAR 45
DEGREE OVER FAR SOUTHERN COUNTIES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON DEPARTURE OF RAINFALL AND CLOUDS ON
THURSDAY. LINGERING RAINFALL EXPECTED TO END FROM WEST TO EAST
ACROSS THE REGION DURING THE MORNING AS FRONTAL BOUNDARY SHIFTS AWAY
TO THE EAST. HELD ONTO PREVIOUS FORECAST THINKING OF KEEPING ANY
THUNDER MENTION OUT FOR THURSDAY MORNING WITH SOUNDINGS SHOWING NO
ELEVATED INSTABILITY IN WAKE OF THE BOUNDARY. ISSUE DURING THE DAY
WILL BECOME HOW QUICKLY LOW STRATUS DEPARTS WITH HIGH PRESSURE
EXPANDING INTO THE OHIO VALLEY FROM THE WEST. LOW LEVEL RH PROGS AND
MODEL SOUNDINGS BOTH SHOWING SHALLOW MOISTURE BECOMING TRAPPED
UNDERNEATH A FAIRLY SHARP INVERSION. INVERSION GIVES WAY ONLY SLOWLY
DESPITE THE INCREASING SUBSIDENCE AS THE DAY PROGRESSES. HELD OFF ON
FULLY CLEARING SKIES UNTIL LATE AFTERNOON/EARLY EVENING AS THE
INVERSION FINALLY GIVES WAY.
REMAINDER OF THE SHORT TERM LOOKS QUIET AS HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. EXPECT MAINLY CLEAR SKIES THURSDAY NIGHT AND
FRIDAY WITH JUST PERIODS OF CIRRUS FROM TIME TO TIME. LIKELY TO SEE
A BUMP UP IN CLOUD COVERAGE FRIDAY NIGHT AS A SHORTWAVE ALOFT WITH A
WEAK SURFACE WAVE PINWHEELS THROUGH THE LOWER GREAT LAKES. OP GFS
REMAINS ALONE IN CONTINUING TO ADVERTISE INCREASING LOW LEVEL
MOISTURE INTO THE REGION RIGHT AT THE END OF THE PERIOD EARLY
SATURDAY DUE TO ENHANCED PHASING ALOFT BETWEEN THE AFOREMENTIONED
SHORTWAVE AND A DEVELOPING STORM SYSTEM OVER THE NORTHERN GULF OF
MEXICO. PREFER MODEL CONSENSUS WHICH MAINTAINS NO IMPACTS OTHER THAN
SUBTLE INCREASES IN MID AND HIGH LEVEL CLOUD COVERAGE AS PREDOMINANT
NORTHERLY FLOW THROUGH THE BOUNDARY LAYER CUTS OFF ANY ADVECTION OF
GULF MOISTURE INTO THE OHIO VALLEY.
TEMPS...UNDERCUT MOS GUIDANCE FOR TEMPS THURSDAY AS LINGERING LOW
CLOUDS ARE LIKELY TO STUNT TEMP RISES IN COLD ADVECTION REGIME. WENT
FAIRLY CLOSE TO MAVMOS GUIDANCE THROUGH THE REST OF THE PERIOD AS
HIGHS SHOULD RECOVER INTO THE UPPER 40S ON FRIDAY. LOWS RANGING FROM
THE MID 20S TO LOWER 30S ARE ANTICIPATED THURS/FRI NIGHTS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LATEST INITIALIZATION CONTINUES TO FAVOR THE NAM AND CANADIAN IN
REGARD TO POSSIBLE PRECIP ON SATURDAY. ACCORDING TO THOSE
MODELS...IT WILL BE A DRY FORECAST AS 2 DISTURBANCES JUST MISS
CENTRAL INDIANA...ONE TO THE NORTH AND ONE TO THE SOUTH.
HOWEVER...THE EXCEPTION CONTINUES TO BE THE GFS. FOR NOW...WILL
STICK WITH MODEL CONSENSUS AND LEAVE PRECIP OUT OF FORECAST.
BEYOND THAT...ALL MODELS ARE INDICATING RAIN ACROSS FORECAST AREA
EARLY WEDNESDAY MORNING THROUGH THURSDAY MORNING AS THE NEXT LOW
PRESSURE SYSTEM MOVES IN. THERE IS STILL SOME DISCREPANCY IN REGARD
TO TIMING OF SYSTEM...WITH THE GFS BEING SLOWER THAN THE EURO.
CONFIDENCE IS NOT HIGH ENOUGH TO GO ANY HIGHER THAN CHANCE POPS AT
THIS TIME. SO WILL NOT DEVIATE FROM INITIALIZATION NUMBERS. WILL
ALSO STAY WITH MODEL BLEND IN REGARD TO TEMPS THROUGH DURATION OF
LONG TERM.
&&
.AVIATION /DISCUSSION FOR THE 160300Z TAF UPDATES/...
IMPROVED CONDITIONS TO MVFR EXCEPT AT LAF WHERE THE IFR CEILINGS
HAVE HUNG AROUND. ALSO...LOOKS LIKE THE BULK OF THE RAIN WILL BE
OVER IN THE NEXT FEW HOURS...SO ONLY WENT WITH VCSH AND TEMPO GROUPS
AFTER 05Z AT ALL SITES WITH CEILINGS DETERIORATING TO IFR ONCE AGAIN
AFTER 05Z AS WELL. PREVIOUS DISCUSSION FOLLOWS...
TRENDS AND SREF MODEL LOW CEILING PROBABILITIES SUGGESTS THE TAF
SITES WILL START OF IFR OR LIFR. OTHERWISE...RADAR TRENDS AND MODELS
SUGGEST RAIN SHOULD BE OCCURRING MUCH OF THE NIGHT BEFORE ENDING
AFTER 08Z AT LAF AND HUF AND 10Z AT IND AND BMG AS AN OCCLUDED FRONT
MOVES THROUGH FROM THE WEST. THE IFR OR WORSE CEILINGS SHOULD
IMPROVE TO MVFR AND THEN VFR AFTER 20Z WITH CLEARING EXPECTED AFTER
00Z FRIDAY.
SOUTHEAST WINDS LESS THAN 10 KNOTS TONIGHT ARE EXPECTED TO VEER TO
SOUTHWEST AND THEN WEST OR NORTHWEST IN THE WAKE OF THE FRONTAL
SYSTEM. WINDS WILL INCREASE TO 10 KNOTS OR MORE AS WELL BEHIND THE
FRONT WITH BUFKIT SUGGESTING GUSTS TO 18 KNOTS POSSIBLE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
802 PM EST WED FEB 15 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE OHIO VALLEY TONIGHT...BRINGING
WIDESPREAD RAIN AND PERHAPS A COUPLE THUNDERSTORMS FOR CENTRAL
INDIANA. CHANCES FOR RAIN WILL END BY MIDDAY THURSDAY AS THE LOW
PULLS AWAY TO THE EAST. HIGH PRESSURE WILL EXPAND INTO THE REGION BY
THURSDAY NIGHT...WITH DRY WEATHER AND SEASONABLE TEMPERATURES
EXPECTED THROUGH THE WEEKEND. PRECIP CHANCES WILL RETURN FOR NEXT
TUESDAY AND WEDNESDAY AS A COLD FRONT MOVES THROUGH THE REGION.
&&
.NEAR TERM /TONIGHT/...
TEMPERATURES ARE A LITTLE COOLER THAN EXPECTED THIS
EVENING...ESPECIALLY ACROSS THE SOUTH. THUS HAVE LOWERED MIN
TEMPERATURES SOME LOCATIONS...MAINLY ACROSS THE SOUTH HALF OF THE
AREA. ALSO...PUSHED BACK THUNDER MENTION UNTIL AFTER MIDNIGHT
BASED ON EXPECTED TIMING OF INSTABILITY. PREVIOUS DISCUSSION
FOLLOWS...
LIGHT RAINFALL CONTINUES TO EXPAND ACROSS CENTRAL INDIANA THIS
AFTERNOON AHEAD OF A FRONTAL BOUNDARY MOVING APPROACHING FROM THE
WEST. TEMPS HAD WARMED INTO THE MID 40S OVER EASTERN PORTIONS OF THE
FORECAST AREA WHERE PRECIP WAS JUST BEGINNING TO ARRIVE. FURTHER
WEST AS RAINFALL BEGINS...TEMPS SLIDING BACK A FEW DEGREES INTO THE
LOWER 40S.
FORECAST FOCUS TONIGHT IS ON RAIN CHANCES AS FRONTAL BOUNDARY
ARRIVES AND A SURFACE WAVE TRACKS THROUGH THE REGION. HAVE RELIED
MORE ON THE HRRR FOR RAINFALL COVERAGE INTO THIS EVENING AS BOTH THE
NAM AND OP GFS ALREADY ARE TOO FAR NORTH AND NOT CAPTURING THE
WIDESPREAD NATURE OF THE LIGHT PRECIP PROPERLY.
BROAD SURFACE WAVE CURRENTLY LOCATED OVER OKLAHOMA WILL MOVE
STEADILY NORTHEAST INTO THE OHIO VALLEY OVERNIGHT. WHILE PRECIP WILL
REMAIN LIGHT OVER THE NEXT FEW HOURS...RAINFALL INTENSITY SHOULD
INCREASE DURING THE EVENING AS 35-40KT LOW LEVEL JET PUMPS DEEPER
MOISTURE INTO THE REGION AHEAD OF THE APPROACHING WAVE. BOTH OP GFS
AND NAM INDICATE FAVORABLE PRECIP EFFICIENCY PROGS AFTER MIDNIGHT AS
LOW LEVEL CONVERGENCE BELOW 700MB MAXIMIZES AND COINCIDES WITH AN
AXIS OF PRECIP WATER VALUES APPROACHING 1 INCH. ENHANCED FORCING
ALOFT WILL ALSO CONTRIBUTE TO WIDESPREAD RAINFALL WITH EMBEDDED
CONVECTIVE ELEMENTS OVERNIGHT. HAVE CONTINUED WITH 100 POPS FOR THE
ENTIRE FORECAST AREA...SPECIFICALLY FOCUSED AFTER MIDNIGHT WHEN
FORCING AND MOISTURE ARE GREATEST. MODEL SOUNDINGS SHOWING WEAK
ELEVATED INSTABILITY WHICH MAY BE ENOUGH TO GENERATE A FEW
THUNDERSTORMS OVER THE AREA LATE TONIGHT AS THE BOUNDARY APPROACHES
AND WILL CONTINUE TO CARRY SLIGHT CHANCES FOR THUNDER. QPF VALUES OF
0.40 TO 0.75 INCHES STILL LOOKS QUITE REASONABLE BY DAYBREAK
THURSDAY.
TEMPS...TEMPS NOT LIKELY TO FALL MUCH OVERNIGHT AS COOLER AIR REALLY
DOES NOT START TO WORK INTO THE REGION UNTIL RIGHT NEAR DAYBREAK AS
THE FRONT SWEEPS THROUGH THE AREA. LAMP DATA DOING A MUCH BETTER JOB
THAN MOS CAPTURING THIS THINKING...AND HAVE LEANED MUCH CLOSER TO
ITS NUMBERS WITH LOWS RANGING FROM THE UPPER 30S NORTH TO NEAR 45
DEGREE OVER FAR SOUTHERN COUNTIES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON DEPARTURE OF RAINFALL AND CLOUDS ON
THURSDAY. LINGERING RAINFALL EXPECTED TO END FROM WEST TO EAST
ACROSS THE REGION DURING THE MORNING AS FRONTAL BOUNDARY SHIFTS AWAY
TO THE EAST. HELD ONTO PREVIOUS FORECAST THINKING OF KEEPING ANY
THUNDER MENTION OUT FOR THURSDAY MORNING WITH SOUNDINGS SHOWING NO
ELEVATED INSTABILITY IN WAKE OF THE BOUNDARY. ISSUE DURING THE DAY
WILL BECOME HOW QUICKLY LOW STRATUS DEPARTS WITH HIGH PRESSURE
EXPANDING INTO THE OHIO VALLEY FROM THE WEST. LOW LEVEL RH PROGS AND
MODEL SOUNDINGS BOTH SHOWING SHALLOW MOISTURE BECOMING TRAPPED
UNDERNEATH A FAIRLY SHARP INVERSION. INVERSION GIVES WAY ONLY SLOWLY
DESPITE THE INCREASING SUBSIDENCE AS THE DAY PROGRESSES. HELD OFF ON
FULLY CLEARING SKIES UNTIL LATE AFTERNOON/EARLY EVENING AS THE
INVERSION FINALLY GIVES WAY.
REMAINDER OF THE SHORT TERM LOOKS QUIET AS HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. EXPECT MAINLY CLEAR SKIES THURSDAY NIGHT AND
FRIDAY WITH JUST PERIODS OF CIRRUS FROM TIME TO TIME. LIKELY TO SEE
A BUMP UP IN CLOUD COVERAGE FRIDAY NIGHT AS A SHORTWAVE ALOFT WITH A
WEAK SURFACE WAVE PINWHEELS THROUGH THE LOWER GREAT LAKES. OP GFS
REMAINS ALONE IN CONTINUING TO ADVERTISE INCREASING LOW LEVEL
MOISTURE INTO THE REGION RIGHT AT THE END OF THE PERIOD EARLY
SATURDAY DUE TO ENHANCED PHASING ALOFT BETWEEN THE AFOREMENTIONED
SHORTWAVE AND A DEVELOPING STORM SYSTEM OVER THE NORTHERN GULF OF
MEXICO. PREFER MODEL CONSENSUS WHICH MAINTAINS NO IMPACTS OTHER THAN
SUBTLE INCREASES IN MID AND HIGH LEVEL CLOUD COVERAGE AS PREDOMINANT
NORTHERLY FLOW THROUGH THE BOUNDARY LAYER CUTS OFF ANY ADVECTION OF
GULF MOISTURE INTO THE OHIO VALLEY.
TEMPS...UNDERCUT MOS GUIDANCE FOR TEMPS THURSDAY AS LINGERING LOW
CLOUDS ARE LIKELY TO STUNT TEMP RISES IN COLD ADVECTION REGIME. WENT
FAIRLY CLOSE TO MAVMOS GUIDANCE THROUGH THE REST OF THE PERIOD AS
HIGHS SHOULD RECOVER INTO THE UPPER 40S ON FRIDAY. LOWS RANGING FROM
THE MID 20S TO LOWER 30S ARE ANTICIPATED THURS/FRI NIGHTS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LATEST INITIALIZATION CONTINUES TO FAVOR THE NAM AND CANADIAN IN
REGARD TO POSSIBLE PRECIP ON SATURDAY. ACCORDING TO THOSE
MODELS...IT WILL BE A DRY FORECAST AS 2 DISTURBANCES JUST MISS
CENTRAL INDIANA...ONE TO THE NORTH AND ONE TO THE SOUTH.
HOWEVER...THE EXCEPTION CONTINUES TO BE THE GFS. FOR NOW...WILL
STICK WITH MODEL CONSENSUS AND LEAVE PRECIP OUT OF FORECAST.
BEYOND THAT...ALL MODELS ARE INDICATING RAIN ACROSS FORECAST AREA
EARLY WEDNESDAY MORNING THROUGH THURSDAY MORNING AS THE NEXT LOW
PRESSURE SYSTEM MOVES IN. THERE IS STILL SOME DISCREPANCY IN REGARD
TO TIMING OF SYSTEM...WITH THE GFS BEING SLOWER THAN THE EURO.
CONFIDENCE IS NOT HIGH ENOUGH TO GO ANY HIGHER THAN CHANCE POPS AT
THIS TIME. SO WILL NOT DEVIATE FROM INITIALIZATION NUMBERS. WILL
ALSO STAY WITH MODEL BLEND IN REGARD TO TEMPS THROUGH DURATION OF
LONG TERM.
&&
.AVIATION /DISCUSSION FOR THE 160000Z TAF ISSUANCE/...
TRENDS AND SREF MODEL LOW CEILING PROBABILITIES SUGGESTS THE TAF
SITES WILL START OF IFR OR LIFR. OTHERWISE...RADAR TRENDS AND MODELS
SUGGEST RAIN SHOULD BE OCCURRING MUCH OF THE NIGHT BEFORE ENDING
AFTER 08Z AT LAF AND HUF AND 10Z AT IND AND BMG AS AN OCCLUDED FRONT
MOVES THROUGH FROM THE WEST. THE IFR OR WORSE CEILINGS SHOULD
IMPROVE TO MVFR AND THEN VFR AFTER 20Z WITH CLEARING EXPECTED AFTER
00Z FRIDAY.
SOUTHEAST WINDS LESS THAN 10 KNOTS TONIGHT ARE EXPECTED TO VEER TO
SOUTHWEST AND THEN WEST OR NORTHWEST IN THE WAKE OF THE FRONTAL
SYSTEM. WINDS WILL INCREASE TO 10 KNOTS OR MORE AS WELL BEHIND THE
FRONT WITH BUFKIT SUGGESTING GUSTS TO 18 KNOTS POSSIBLE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/50
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
600 PM EST WED FEB 15 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE OHIO VALLEY TONIGHT...BRINGING
WIDESPREAD RAIN AND PERHAPS A COUPLE THUNDERSTORMS FOR CENTRAL
INDIANA. CHANCES FOR RAIN WILL END BY MIDDAY THURSDAY AS THE LOW
PULLS AWAY TO THE EAST. HIGH PRESSURE WILL EXPAND INTO THE REGION BY
THURSDAY NIGHT...WITH DRY WEATHER AND SEASONABLE TEMPERATURES
EXPECTED THROUGH THE WEEKEND. PRECIP CHANCES WILL RETURN FOR NEXT
TUESDAY AND WEDNESDAY AS A COLD FRONT MOVES THROUGH THE REGION.
&&
.NEAR TERM /TONIGHT/...
LIGHT RAINFALL CONTINUES TO EXPAND ACROSS CENTRAL INDIANA THIS
AFTERNOON AHEAD OF A FRONTAL BOUNDARY MOVING APPROACHING FROM THE
WEST. TEMPS HAD WARMED INTO THE MID 40S OVER EASTERN PORTIONS OF THE
FORECAST AREA WHERE PRECIP WAS JUST BEGINNING TO ARRIVE. FURTHER
WEST AS RAINFALL BEGINS...TEMPS SLIDING BACK A FEW DEGREES INTO THE
LOWER 40S.
FORECAST FOCUS TONIGHT IS ON RAIN CHANCES AS FRONTAL BOUNDARY
ARRIVES AND A SURFACE WAVE TRACKS THROUGH THE REGION. HAVE RELIED
MORE ON THE HRRR FOR RAINFALL COVERAGE INTO THIS EVENING AS BOTH THE
NAM AND OP GFS ALREADY ARE TOO FAR NORTH AND NOT CAPTURING THE
WIDESPREAD NATURE OF THE LIGHT PRECIP PROPERLY.
BROAD SURFACE WAVE CURRENTLY LOCATED OVER OKLAHOMA WILL MOVE
STEADILY NORTHEAST INTO THE OHIO VALLEY OVERNIGHT. WHILE PRECIP WILL
REMAIN LIGHT OVER THE NEXT FEW HOURS...RAINFALL INTENSITY SHOULD
INCREASE DURING THE EVENING AS 35-40KT LOW LEVEL JET PUMPS DEEPER
MOISTURE INTO THE REGION AHEAD OF THE APPROACHING WAVE. BOTH OP GFS
AND NAM INDICATE FAVORABLE PRECIP EFFICIENCY PROGS AFTER MIDNIGHT AS
LOW LEVEL CONVERGENCE BELOW 700MB MAXIMIZES AND COINCIDES WITH AN
AXIS OF PRECIP WATER VALUES APPROACHING 1 INCH. ENHANCED FORCING
ALOFT WILL ALSO CONTRIBUTE TO WIDESPREAD RAINFALL WITH EMBEDDED
CONVECTIVE ELEMENTS OVERNIGHT. HAVE CONTINUED WITH 100 POPS FOR THE
ENTIRE FORECAST AREA...SPECIFICALLY FOCUSED AFTER MIDNIGHT WHEN
FORCING AND MOISTURE ARE GREATEST. MODEL SOUNDINGS SHOWING WEAK
ELEVATED INSTABILITY WHICH MAY BE ENOUGH TO GENERATE A FEW
THUNDERSTORMS OVER THE AREA LATE TONIGHT AS THE BOUNDARY APPROACHES
AND WILL CONTINUE TO CARRY SLIGHT CHANCES FOR THUNDER. QPF VALUES OF
0.40 TO 0.75 INCHES STILL LOOKS QUITE REASONABLE BY DAYBREAK
THURSDAY.
TEMPS...TEMPS NOT LIKELY TO FALL MUCH OVERNIGHT AS COOLER AIR REALLY
DOES NOT START TO WORK INTO THE REGION UNTIL RIGHT NEAR DAYBREAK AS
THE FRONT SWEEPS THROUGH THE AREA. LAMP DATA DOING A MUCH BETTER JOB
THAN MOS CAPTURING THIS THINKING...AND HAVE LEANED MUCH CLOSER TO
ITS NUMBERS WITH LOWS RANGING FROM THE UPPER 30S NORTH TO NEAR 45
DEGREE OVER FAR SOUTHERN COUNTIES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON DEPARTURE OF RAINFALL AND CLOUDS ON
THURSDAY. LINGERING RAINFALL EXPECTED TO END FROM WEST TO EAST
ACROSS THE REGION DURING THE MORNING AS FRONTAL BOUNDARY SHIFTS AWAY
TO THE EAST. HELD ONTO PREVIOUS FORECAST THINKING OF KEEPING ANY
THUNDER MENTION OUT FOR THURSDAY MORNING WITH SOUNDINGS SHOWING NO
ELEVATED INSTABILITY IN WAKE OF THE BOUNDARY. ISSUE DURING THE DAY
WILL BECOME HOW QUICKLY LOW STRATUS DEPARTS WITH HIGH PRESSURE
EXPANDING INTO THE OHIO VALLEY FROM THE WEST. LOW LEVEL RH PROGS AND
MODEL SOUNDINGS BOTH SHOWING SHALLOW MOISTURE BECOMING TRAPPED
UNDERNEATH A FAIRLY SHARP INVERSION. INVERSION GIVES WAY ONLY SLOWLY
DESPITE THE INCREASING SUBSIDENCE AS THE DAY PROGRESSES. HELD OFF ON
FULLY CLEARING SKIES UNTIL LATE AFTERNOON/EARLY EVENING AS THE
INVERSION FINALLY GIVES WAY.
REMAINDER OF THE SHORT TERM LOOKS QUIET AS HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. EXPECT MAINLY CLEAR SKIES THURSDAY NIGHT AND
FRIDAY WITH JUST PERIODS OF CIRRUS FROM TIME TO TIME. LIKELY TO SEE
A BUMP UP IN CLOUD COVERAGE FRIDAY NIGHT AS A SHORTWAVE ALOFT WITH A
WEAK SURFACE WAVE PINWHEELS THROUGH THE LOWER GREAT LAKES. OP GFS
REMAINS ALONE IN CONTINUING TO ADVERTISE INCREASING LOW LEVEL
MOISTURE INTO THE REGION RIGHT AT THE END OF THE PERIOD EARLY
SATURDAY DUE TO ENHANCED PHASING ALOFT BETWEEN THE AFOREMENTIONED
SHORTWAVE AND A DEVELOPING STORM SYSTEM OVER THE NORTHERN GULF OF
MEXICO. PREFER MODEL CONSENSUS WHICH MAINTAINS NO IMPACTS OTHER THAN
SUBTLE INCREASES IN MID AND HIGH LEVEL CLOUD COVERAGE AS PREDOMINANT
NORTHERLY FLOW THROUGH THE BOUNDARY LAYER CUTS OFF ANY ADVECTION OF
GULF MOISTURE INTO THE OHIO VALLEY.
TEMPS...UNDERCUT MOS GUIDANCE FOR TEMPS THURSDAY AS LINGERING LOW
CLOUDS ARE LIKELY TO STUNT TEMP RISES IN COLD ADVECTION REGIME. WENT
FAIRLY CLOSE TO MAVMOS GUIDANCE THROUGH THE REST OF THE PERIOD AS
HIGHS SHOULD RECOVER INTO THE UPPER 40S ON FRIDAY. LOWS RANGING FROM
THE MID 20S TO LOWER 30S ARE ANTICIPATED THURS/FRI NIGHTS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LATEST INITIALIZATION CONTINUES TO FAVOR THE NAM AND CANADIAN IN
REGARD TO POSSIBLE PRECIP ON SATURDAY. ACCORDING TO THOSE
MODELS...IT WILL BE A DRY FORECAST AS 2 DISTURBANCES JUST MISS
CENTRAL INDIANA...ONE TO THE NORTH AND ONE TO THE SOUTH.
HOWEVER...THE EXCEPTION CONTINUES TO BE THE GFS. FOR NOW...WILL
STICK WITH MODEL CONSENSUS AND LEAVE PRECIP OUT OF FORECAST.
BEYOND THAT...ALL MODELS ARE INDICATING RAIN ACROSS FORECAST AREA
EARLY WEDNESDAY MORNING THROUGH THURSDAY MORNING AS THE NEXT LOW
PRESSURE SYSTEM MOVES IN. THERE IS STILL SOME DISCREPANCY IN REGARD
TO TIMING OF SYSTEM...WITH THE GFS BEING SLOWER THAN THE EURO.
CONFIDENCE IS NOT HIGH ENOUGH TO GO ANY HIGHER THAN CHANCE POPS AT
THIS TIME. SO WILL NOT DEVIATE FROM INITIALIZATION NUMBERS. WILL
ALSO STAY WITH MODEL BLEND IN REGARD TO TEMPS THROUGH DURATION OF
LONG TERM.
&&
.AVIATION /DISCUSSION FOR THE 160000Z TAF ISSUANCE/...
TRENDS AND SREF MODEL LOW CEILING PROBABILITIES SUGGESTS THE TAF
SITES WILL START OF IFR OR LIFR. OTHERWISE...RADAR TRENDS AND MODELS
SUGGEST RAIN SHOULD BE OCCURRING MUCH OF THE NIGHT BEFORE ENDING
AFTER 08Z AT LAF AND HUF AND 10Z AT IND AND BMG AS AN OCCLUDED FRONT
MOVES THROUGH FROM THE WEST. THE IFR OR WORSE CEILINGS SHOULD
IMPROVE TO MVFR AND THEN VFR AFTER 20Z WITH CLEARING EXPECTED AFTER
00Z FRIDAY.
SOUTHEAST WINDS LESS THAN 10 KNOTS TONIGHT ARE EXPECTED TO VEER TO
SOUTHWEST AND THEN WEST OR NORTHWEST IN THE WAKE OF THE FRONTAL
SYSTEM. WINDS WILL INCREASE TO 10 KNOTS OR MORE AS WELL BEHIND THE
FRONT WITH BUFKIT SUGGESTING GUSTS TO 18 KNOTS POSSIBLE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
542 PM CST WED FEB 15 2012
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 353 PM CST WED FEB 15 2012
TONIGHT:
THE NEAR TERM/MESOSCALE CONCERN FOR TONIGHT WAS WHAT TO DO WITH POPS
FROM THE LATEST KDDC WSR-88D TRENDS. THIS PRECIPITATION IS BEING CAUSED
BY A 700 HPA DEFORMATION AXIS ON THE BACKSIDE OF A SHORTWAVE TROUGH.
RUC AND PARTICULARLY HRRR WERE AGGRESSIVE WITH FORECAST COMPOSITE REFLECTIVITIES
THIS MORNING. IN ADDITION, 700 HPA OMEGA WAS ALSO NOTED IN THE SAME
REGION. THE 700 HPA DEFORMATION ZONE PER SATELLITE OBSERVATIONS IS
BECOMING STRETCHED ALONG AN AXIS OF DILATATION. THEREFORE HAVE TRIMMED
THE POPS EVEN FURTHER FROM AN UPDATE THIS MORNING WITH THE AERIAL COVERAGE
OF SHOWERS DIMINISHING TO NOTHING BY 00Z TONIGHT.
MODELS SHOW THAT AFTER 00Z, LOWER DEWPOINT ADVECTION WILL OCCUR AT THE
SURFACE. FORECAST SOUNDINGS ALSO SHOW A DRYING IN THE LOW TO MID LEVELS.
THEREFORE HAVE A CLEARING TREND IN THE SKY GRIDS. A LIGHT NORTHWESTERLY
TO NORTHERLY WIND IS EXPECTED OVERNIGHT. OVERNIGHT LOWS WILL BE PRIMARILY
IN THE 20S DEG F.
THURSDAY:
A FORECAST CONCERN THAT WAS MENTIONED IN THE TAF SECTION BELOW WAS THE
POTENTIAL FOR FREEZING FOG. MOS GUIDANCE WAS AGGRESSIVE, INCLUDING LAMP
GUIDANCE, IN BRINGING LOW STRATUS AND FOG BACK TO THE REGION TOMORROW.
BUFKIT FORECAST SOUNDINGS SHOW THAT THE LAYER OF SATURATION IS NEAR
THE SURFACE AND DOESN`T EXTEND VERY FAR UP IN THE ATMOSPHERIC COLUMN
FOR CONSIDERABLE DRYING/LARGE DEWPOINT DEPRESSIONS ARE FORECAST. AS
A RESULT, WILL NOT BRING THE MENTION OF FREEZING FOG IN THE FORECAST
FOR NOW. FROST LOOKS MORE LIKELY AT THE SURFACE. EVEN IF FREEZING
FOG DOES OCCUR, IT SHOULD BE VERY PATCHY DUE TO DRY AIR IMMEDIATELY
ABOVE THE SURFACE, INCLUDING WITHIN THE BOUNDARY LAYER.
WINDS TOMORROW MORNING WILL BE LIGHT AND VARIABLE AS A CENTER OF HIGH
PRESSURE MOVES ACROSS KANSAS. SOUTHERLY WINDS WILL DEVELOP BY TOMORROW
AFTERNOON ACROSS THE FA ON THE WEST SIDE OF THE DEPARTING HIGH. HIGHS
TOMORROW SHOULD BE IN THE UPPER 40S AND NEAR 50 DEG F. NO PRECIPITATION
IS EXPECTED IN THE WAKE OF THE DEPARTING UPPER LEVEL SHORTWAVE TROUGH
AND WITH SUBSIDENCE EXPECTED THROUGH THE ATMOSPHERIC COLUMN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 353 PM CST WED FEB 15 2012
A FAIRLY ACTIVE UPPER LEVEL FLOW PATTERN IS FORECAST TO CONTINUE THROUGH
THE EXTENDED PERIOD. AT THE BEGINNING OF THE PERIOD A BROAD TROUGH WILL
BE SITUATED FROM HUDSON BAY INTO THE UPPER MIDWEST AND GREAT LAKES REGION
WITH A SHORTWAVE TROUGH DROPPING SOUTH OUT OF CANADA INTO THE NORTHERN
HIGH PLAINS. A TROUGH/CLOSED LOW WILL BE OVER THE DESERT SOUTHWEST
INTO NORTHWEST MEXICO. THE GFS MODEL SHOWS THE NORTHERN PLAINS SHORTWAVE
PHASING WITH THE SOUTHWEST CONUS SYSTEM WITH THE RESULTANT TROUGH MOVING
INTO THE MISSISSIPPI VALLEY BY LATE IN THE WEEKEND. THIS MODEL ALSO
BREAKS OUT SOME LIGHT PRECIPITATION OVER THE SOUTHERN PART OF THE
FORECAST AREA SATURDAY NIGHT.
THE ECMWF AND CANADIAN MODELS SHOW THE TWO SYSTEMS REMAINING SEPARATE
WITH BOTH SYSTEMS PASSING BY EITHER NORTH OR SOUTH OF THE CENTRAL
HIGH PLAINS. THE GFS HAS STRUGGLED WITH THIS SYSTEM OVER THE PAST
SEVERAL RUNS WHICH LEADS LESS CREDENCE TO THAT MODEL SOLUTION.
WILL GO WITH A DRY FORECAST FOR THAT TIME PERIOD.
WHILE THIS WAVE IS MOVING EAST OF THE CENTRAL CONUS...ANOTHER SYSTEM
WILL BE MOVING INTO THE ROCKIES. BY SUNDAY NIGHT AND MONDAY THE ECMWF
SHOWS A PIECE OF THIS WAVE EJECTING OUT OVER WESTERN KANSAS WITH PRECIPITATION
BREAKING OUT OVER WESTERN KANSAS. THE MODELS HAVE DIFFERING SOLUTIONS
IN HOW THIS WAVE WILL EVOLVE AND WHEN IT WILL MOVE OUT THROUGH THE
CENTRAL CONUS. NOT REAL CONFIDENT IN ANY SOLUTION BUT THE ECMWF
SEEMS TO SHOW A LITTLE MORE CONTINUITY WITH ITS PREVIOUS RUNS. THE
LATEST CR INIT HAS CHANCE/SLIGHT CHANCE POPS ESPECIALLY ACROSS THE
NORTHERN 2/3RDS OFF THE CWA WHICH LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 537 PM CST WED FEB 15 2012
THE UPPER LEVEL WAVE APPEARS TO BE LOSING ITS BAROCLINICITY THIS
EVENING AS THE CLOSED MID LEVEL CIRCULATION BECOMES MORE OF AN OPEN
WAVE AND LIFTS INTO EASTERN KANSAS. THE CURRENT OBSERVATIONS FROM
SATELLITE AND METARS SHOW MUCH DRIER NORTH WINDS SETTLING ACROSS
THE AREA AND RADAR ECHOES HAVE SIGNIFICANTLY DIMINISHED. CEILINGS
HAVE ERODED AT GCK AND SHOULD BECOME SCATTERED AS WELL AT KHYS AND
KDDC WITHIN THE NEXT 2 HOURS. THE OVERNIGHT FORECAST WILL BE A
CHALLENGE AS SOME LOW LEVEL IFR STRATUS IS INDICATED IN THE LOCAL
GFS MOS GUIDANCE AS WELL AND SUPPORTED BY THE LOW LEVEL NAM
RELATIVELY HUMIDITY FIELDS. THE CHALLENGE IS THAT THIS POTENTIAL
STRATUS APPEARS TO BE LIMITED IN AREAL COVERAGE AND MAY OR MAY NOT
AFFECT ANY OF THE TERMINALS, RESULTING IN A LOW CONFIDENCE
FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 48 26 50 / 10 0 0 10
GCK 19 48 24 51 / 10 0 0 0
EHA 21 49 27 53 / 10 0 0 10
LBL 22 51 25 53 / 10 0 0 10
HYS 21 47 26 47 / 10 0 0 0
P28 26 50 27 54 / 10 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM....GERARD
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1128 AM EST TUE FEB 14 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL BRING A MIX OF SNOW AND RAIN SHOWERS THIS
AFTERNOON INTO TONIGHT. HIGH PRESSURE WILL FOLLOW WITH A DRY
WEDNESDAY. A BETTER DEVELOPED LOW PRESSURE SYSTEM, COMING
NORTHEAST FROM NEW MEXICO, WILL BRING ANOTHER ROUND OF RAIN SHOWERS
AND SNOW SHOWERS WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE MADE SMALL ADJUSTMENTS TO WEATHER TYPE AND TEMPERATURES FOR
THIS AFTERNOON AND TONIGHT, BASED ON RECENT RADAR AND SURFACE
DATA, PLUS HRRR AND NAM MODEL OUTPUT.
HAVE OPTED TO CHARACTERIZE THE SPOTTY INCOMING PRECIPITATION AS
SHOWERY. DUE TO THE ADIABATIC STEEPNESS OF THE SURFACE LAYER
TEMPERATURE LAPSE RATE, SURFACE TEMPERATURES MAY HAVE TO GET TO 35
BEFORE A CHANGE FROM SNOW TO RAIN OCCURS. HOWEVER, DUE TO THE
EXPECTED LIGHTNESS OF THE PRECIPITATION AMOUNTS, ONCE GROUND
TEMPERATURES REACH 33, EXPECT LITTLE IF ANY SNOW ACCUMULATION,
PARTICULARLY ON PREVIOUSLY TREATED PAVEMENTS.
POST SYSTEM SHOWERS WILL ALSO BE LIGHT DUE TO WEAKNESS OF SYSTEM,
ALTHOUGH SNOW AMOUNTS NORTH AND MOUNTAINS MAY TOP OUT NEAR 2
INCHES FROM THE ENTIRE EVENT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
SREF MODEL OUTPUT CONTINUES TO SHOW ENSUING HIGH PRESSURE
PROVIDING A DRY BREAK WEDNESDAY INTO WEDNESDAY EVENING. THEN A
SECOND LOW PRESSURE SYSTEM, MORE DEVELOPED THAN TUESDAY`S SYSTEM,
WILL COME NORTHEASTWARD FROM NEW MEXICO, AND PROVIDE ANOTHER BOUT OF
SHOWERS OF SNOW AND RAIN LATE WEDNESDAY NIGHT AND THURSDAY.
THE ONSET OF THE PRECIP WITH THIS SYSTEM WILL BE DIFFICULT AS
WELL. ALL INDICATIONS ARE THAT THERE WILL BE STRONG WAA AHEAD OF
THE SFC LOW, WHICH WILL ALLOW FOR RISING TEMPS WED NIGHT. THE
AREAS THAT WILL NEED TO BE CLOSELY WATCHED, WILL BE ACROSS THE FAR
NORTHEAST AND GARRETT COUNTY. THIS WILL COME MORE INTO FOCUS IN
LATER MODEL RUNS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AN UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL MOVE NORTHEAST INTO
EASTERN CANADA BY FRIDAY. SCATTERED RAIN AND SNOW SHOWERS SHOULD
BEGIN TO TAPER OFF BY FRIDAY MORNING. LINGERING MOISTURE AND
NORTHWEST FLOW SHOULD MAINTAIN A FEW SHOWERS OVER THE FORECAST AREA
ESPECIALLY NORTH OF I-80 FRIDAY AFTERNOON. WEAK SYSTEMS PASSING TO
OUR NORTH COUPLED WITH MOIST NORTHWEST FLOW WILL MAINTAIN CLOUDS AND
ISOLATED SHOWERS OVER THE REGION DURING THE WEEKEND.
SURFACE HIGH PRESSURE WITH DRIER AIR SHOULD PROVIDE MORE SUNSHINE
ON MONDAY.
TEMPERATURES ARE FORECAST TO BE A FEW DEGREES ABOVE NORMAL DURING
THE EXTENDED PERIOD.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
A WEAK UPPER LEVEL DISTURBANCE WILL INITIALLY PUSH LIGHT SNOW
INTO THE TERMINALS THIS MORNING. VISIBILITY RESTRICTIONS WITH
SNOW WILL MOSTLY BE MVFR WITH BRIEF PERIODS OF IFR. LIGHT
PRECIPITATION WILL CONTINUE INTO THE AFTERNOON, REMAINING MOSTLY
SNOW NORTH OF A LINE FROM ZZV-PIT-LBE, WITH A RAIN-SNOW MIX FROM
THOSE LOCATIONS SOUTH. PRECIP MAY BE MOSTLY RAIN AT LEAST DURING
THE DAYTIME TUESDAY AT MGW.
CEILINGS WILL LOWER TO MVFR TODAY. WINDS WILL GENERALLY REMAIN
OUT OF THE SOUTH FROM 5-10KTS.
A MIX OF SNOW AND RAIN SHOWERS WITH MAINLY MVFR RESTRICTIONS WILL
LIKELY DIMINISH TONIGHT AS THE DISTURBANCE PUSHES EAST OF THE AREA.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
HIGH PRESSURE WILL RETURN VFR CONDITIONS FOR WEDNESDAY.
RESTRICTIONS ARE LIKELY AGAIN THURSDAY INTO FRIDAY DUE TO A MIX
OF RAIN AND SNOW SHOWERS ASSOCIATED WITH THE PASSAGE OF A STRONGER
LOW PRESSURE SYSTEM TRACKING NORTHEAST FROM THE PLAINS.
A MOIST NORTHWEST FLOW BEHIND THE DEPARTING LOW PRESSURE SYSTEM
MAY MAINTAIN AREAS OF MVFR CEILINGS OVER THE TERMINALS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 PM EST WED FEB 15 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 425 PM EST WED FEB 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED SPLIT FLOW PATTERN WITH
TROUGHING OVER THE WRN CONUS AND A FLAT RIDGE OVER THE EAST. ONE NRN
STREAM SHORTWAVE TROUGH WAS LOCATED OVER NW MN WITH ANOTHER TRAILING
OVER SRN SASK INTO NW ND. A VIGOROUS SRN STREAM SHRTWV MOVING FROM
THE TX/OK PANHANDLE INTO SE KS. AT THE SFC...A WEAK TROUGH EXTENDED
FROM NW ONTARIO THROUGH WRN MN LEAVING LIGHT SW FLOW OVER THE NRN
GREAT LAKES. AN AREA OF LIGHT SNOW FROM SRN MN INTO WRN WI WAS
SUPPORTED BY 290K-295K ISENTROPIC ASCENT AHEAD OF THE TROUGH.
TONIGHT AND THU...RADAR TRENDS AND NAM ISENTROPIC PROGS SUGGEST THAT
THE INITIAL AREAS OF PCPN WILL LIFT INTO THE SW CWA THIS EVENING.
HOWEVER...WITH LITTLE INCREASE IN INTENSITY EXPECTED...ONLY
MENTIONED CHANCE POPS WITH SNOW ACCUMULATION OF A HALF INCH OR LESS.
AS THE LAGGING SHORTWAVE MOVES TOWARD THE UPPER MS
VALLEY...INCREASING 700-300 MB QVECTOR CONV WITH THE DEEPENING MID
LEVEL TROUGH WILL ALSO PROVIDE ADDITIONAL SUPPORT FOR AREAS OF LIGHT
SNOW. AGAIN WITH ONLY MODERATE FORCING AND MOISTURE INFLOW...KEPT
ONLY CHANCE POPS WITH SNOW ACCUMULATIONS LESS THAN AN INCH.
HOWEVER...OVER THE ERN CWA...SLIGHTLY GREATER MOISTURE ADVECTION AND
ISENTROPIC ASCENT SHOULD BE ENOUGH FOR MORE WIDESPREAD OR SLIGHTLY
HEAVIER PCPN WITH SNOW AMOUNTS TO AROUND AN INCH.
WITH DEWPOINTS REMAINING IN THE MID 20S OVER THE AREA...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL...WITH READINGS ONLY FALLING INTO THE
MID AND UPPER 20S. CLOUDS AND LIGHT PCPN SHOULD LIMIT MAX READINGS
TO THE MID 30S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 PM EST WED FEB 15 2012
WE START THE PERIOD 00Z FRI WITH A 600MB SHORTWAVE TROUGH AXIS OVER
THE ERN CWA...ANOTHER WEAKER SHORTWAVE OVER NRN MN...AND ANOTHER
STRONGER SHORTWAVE JUST N OF MANITOBA. THIS RESULTS IN A
BROAD...WEAK SFC LOW TO OUR NE...AND A WEAK SFC RIDGE OVER MN. WITH
NW TO WNW LOW LEVEL WINDS...850MB TEMPS AROUND -10C...AND DEEP
MOISTURE...EXPECT SOME LIGHT UPSLOPE SNOW OVER THE WRN CWA AND SOME
LIGHT LAKE ENHANCED SNOW OVER THE ERN CWA AT THE START OF THE
PERIOD.
AS THE NRN MN SHORTWAVE MOVES INTO THE AREA LATE THU NIGHT...LES MAY
BECOME A LITTLE MORE ORGANIZED. BY 12Z FRI...850MB TEMPS WILL HAVE
DECREASED TO AROUND -12C WITH LOW LEVEL WINDS FROM THE NW TO WNW.
WILL DECREASE POPS SOME AFTER THE INITIAL SHORTWAVE PASSAGE AT THE
START OF THE PERIOD...THEN INCREASE POPS LATER THU NIGHT. STILL
EXPECT NOTHING MORE THAN LIGHT LES...WITH MINOR ACCUMULATIONS OF
LESS THAN AN INCH THROUGH THU NIGHT.
850MB TEMPS WILL CONTINUE TO STEADILY DECREASE FRI...AND BE DOWN TO
-14C BY 00Z SAT...BUT SUBSIDENCE BEHIND THE THU NIGHT SHORTWAVE AND
DAYTIME MIXING WILL LEAD TO LES NOT REALLY INCREASING MUCH THROUGH
THE DAY. CHANCE POPS LOOK GOOD FOR FRIDAY IN THE NW TO WNW
SNOWBELTS...WITH AROUND AN INCH OF ADDITIONAL SNOWFALL ACCUMULATIONS.
FRI NIGHT AND SAT ARE MORE COMPLEX AND UNCERTAIN AS A STRONGER
SHORTWAVE TROUGH MOVES OVER THE AREA. MODELS HAVE SHOWN BOTH RUN TO
RUN AND MODEL TO MODEL DISAGREEMENT ON THE STRENGTH AND TIMING OF
THE SHORTWAVE...WHICH HAS A BIG IMPACT ON PRECIP TIMING/COVERAGE.
BESIDES THE OBVIOUS TIMING DIFFERENCES...ONE OF THE BIGGER
DIFFERENCES BETWEEN THE MODELS RESULTS FROM THE STRENGTH OF THE
SYSTEM. ALL MODELS BRING A DEEPENING SFC LOW SOMEWHERE S OF THE
CWA...BUT THE EXACT TRACK OF THE LOW IS WHAT IS IN QUESTION. THE
12Z/15 GFS IS THE STRONGEST AND FARTHEST N WITH THE SFC LOW...WHICH
WOULD BRING A COUPLE OF INCHES OF SNOW TO AREAS OF MENOMINEE COUNTY
AND FAR ERN UPPER MI. THE GFS SOLUTION WOULD ALSO BRING LOW LEVEL
WINDS FROM THE NNE...WHEREAS MOST OTHER MODELS SHOW NW TO NNW LOW
LEVEL WINDS...WHICH WOULD MAKES FOR BIG DIFFERENCES IN LES. WILL NOT
USE THE GFS SOLUTION SINCE IT IS MORE OF AN OUTLIER. THUS...WILL
HAVE HIGH CHANCE TO LOW LIKELY POPS IN NNW TO NW WIND SNOWBELTS FRI
NIGHT AND SAT...DIMINISHING LATE SAT AS SFC HIGH PRESSURE MOVES IN.
DAYS 4 THROUGH 7 (SUNDAY THROUGH NEXT WEDNESDAY)...
MODELS COME INTO BRIEF AGREEMENT AGAIN ON MON WITH AN UPPER LEVEL
RIDGE OVER THE CWA. SFC HIGH PRESSURE E AND LOW PRESSURE W RESULTS
IN WAA OVER THE AREA...WHICH WILL ALLOW HIGHS MON TO BE IN THE MID
30S. MODELS THEN DIVERGE SIGNIFICANTLY WITH SOLUTIONS FROM MON NIGHT
THROUGH THE REST OF THE FORECAST PERIOD. MODELS SHOWS A COUPLE OF
TROUGHS MOVING THROUGH...THE FIRST SOMETIME BETWEEN MON NIGHT
THROUGH TUE NIGHT AND THE OTHER POSSIBLY MOVING INTO THE AREA
SOMETIME LATE WED. SIGNIFICANT RUN TO RUN ERRORS AND MODEL
DISAGREEMENT MAKE FOR LOW CONFIDENCE IN MODELS PAST MON. THE PERIOD
SHOULD GENERALLY BE ABOVE NORMAL WITH RESPECT TO TEMPS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 651 PM EST WED FEB 15 2012
PER SATELLITE/RADAR IMAGERY...SHORTWAVE APPROACHING FROM NRN MN WILL
BRING SOME -SN TO KIWD/KCMX/KSAW DURING THE NIGHT. CLOSER TO
SHORTWAVE TRACK...IFR CONDITIONS ARE MORE LIKELY AT KCMX WHILE LIGHT
UPSLOPE SOUTHERLY FLOW AT KSAW MAY ALSO LEAD TO IFR CONDITIONS
THERE. MVFR CONDITIONS SHOULD PREVAIL AT KIWD AS PCPN PASSES THRU
THE AREA. IMPROVEMENT IS EXPECTED THU BEHIND ASSOCIATED COLD
FROPA...THOUGH MVFR CONDITIONS WILL PROBABLY PREVAIL AT ALL SITES
THRU THE AFTN. HOWEVER...DOWNSLOPING WESTERLY FLOW AT KSAW MAY LEAD
TO A BREAK OUT TO VFR CONDITIONS IN THE AFTN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EST WED FEB 15 2012
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 20 TO 30 KT RANGE THU
INTO THU NIGHT IN THE WAKE OF A TROUGH MOVING THROUGH THE REGION.
OTHERWISE...CONDITIONS WILL REMAIN RELATIVELY TRANQUIL THIS WEEK.
LOW PRESSURE WILL CROSS THE GREAT LAKES THROUGH THE WEEKEND...AND
WINDS WILL GENERALLY BE BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
418 PM EST TUE FEB 14 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 418 PM EST TUE FEB 14 2012
WV IMAGERY AND RUC ANALYSIS INDICATED AN UPSTREAM MID/UPPER LEVEL
SHORTWAVE TROUGH FROM THE ERN DAKOTAS INTO SRN MN. AT THE SFC...LOW
PRES WAS LOCATED OVER SE NORTH DAKOTA. SO FAR..ONLY LIGHT SNOW OR
FLURRIES WERE OBSERVED WITH THE SHRTWV OVER THE DAKOTAS. AHEAD OF
THE LOW WEAK SW FLOW PREVAILED WITH ABUNDANT LOW LEVEL MOISTURE FROM
WI INTO UPPER MI KEEPING LOW CLOUDS OVER THE REGION. WITH THE MILD
AIRMASS OVER THE AREA...TEMPS HAD CLIMBED INTO THE LOWER TO MID 30S
DESPITE THE PERSISTENT CLOUD COVER.
TONIGHT INTO WEDNESDAY...MODELS SUGGEST MID LEVEL FGEN ASSOCIATED
WITH THE DAKOTAS SHRTWV WILL SUPPORT AREAS OF LIGHT SNOW INTO NRN WI
AND UPPER MI LATE TONIGHT INTO WED MORNING. THE FCST LEANS TOWARD
THE 12Z/18Z NAM WITH THE GREATER FORCING/POPS INTO THE SW HALF OF
THE CWA. THERE MAY BE SOME POTENTIAL FOR A PERIOD OF BRIEF HEAVIER
SNOW...GIVEN THE STRENGTH OF THE FORCING. HOWEVER...SINCE THERE
STILL SOME UNCERTAINTY IN WHERE ANY STRONGER PCPN BAND MAY
OCCUR...ONLY CHANCE POPS WERE INCLUDED WITH OVERALL SNOWFALL AMOUNTS
OF LESS THAN AN INCH.
LOOK FOR MINS TONIGHT TO RANGE MAINLY IN THE LOWER 20S OVER THE WRN
INTERIOR TO THE MID 20S NEAR THE GREAT LAKES AND EAST. HIGH TEMPS
WILL AGAIN CLIMB ABOVE NORMAL...INTO THE MID AND UPPER 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 418 PM EST TUE FEB 14 2012
STRONG NORTHERN STREAM SHORTWAVE WILL NEAR THE GREAT LAKES WEDNESDAY
NIGHT INTO THURSDAY MORNING...PHASING WITH A SOUTHERN STREAM
SHORTWAVE MOVING NORTHWEST FROM THE PLAINS. PREVIOUS MODEL RUNS WERE
SHOWING SOME UNCERTAINTY IN THE INTENSITY AND LOCATION OF THIS
PHASING...CAUSING DISCREPANCIES IN QPF AMOUNTS AND LOCATION OF THE
SURFACE LOW ASSOCIATED WITH THE SOUTHERN STREAM. MOST RECENT RUNS
OF GFS/NAM/ECMWF/GEM HAVE SEEM TO COME INTO BETTER AGREEMENT...WITH
GENERAL CONSENSUS HAVING THE SURFACE LOW PRESSURE PASSING OVER LOWER
MI BY EARLY AFTERNOON THURSDAY. DEEPEST MOISTURE WILL BE CONFINED
NEAR THE CENTER OF THE LOW...BUT GOOD CONVERGENCE AND DECENT LAPSE
RATES WILL MOVE INTO UPPER MI...ESPECIALLY EAST AS THE SOUTHERN
SHORTWAVE MOVES FROM SOUTHWEST TO NORTHEAST...BRINGING CHANCES FOR
PRECIP BEGINNING WEDNESDAY NIGHT SOUTH CENTRAL AND REMAINING DURING
THE DAY THURSDAY ACROSS THE SOUTHEAST. NORTHERN WAVE ENERGY WILL
KEEP THE LOW SUPPRESSED FAR ENOUGH SOUTH THAT MOST OF THE MOISTURE
AND LIFT WILL BE CONFINED TO SOUTHEAST WI AND LOWER MI WHERE THE
BEST WAA IS LOCATED...THOUGH 0Z GEM BRINGS SOME OF THE ASSOCIATED
HIGHER QPF VALUES FARTHER NORTH ALONG LAKE MI IN UPPER MI AS WELL.
WILL KEEP WITH HIGHEST QPF AND SNOWFALL TOTALS NEAR THE LAKE MI
SHORELINE...BUT GOING WITH CONSENSUS...ONLY EXPECT SNOWFALL AMOUNTS
TO REACH THE 3 TO 5 INCH RANGE IN THIS AREA.
SURFACE LOW PRESSURE WILL QUICKLY MOVE OFF TO THE NORTHEAST BY
THURSDAY EVENING...FOLLOWED SHORTLY THEREAFTER BY THE ASSOCIATED
PHASED SHORTWAVE. DRY AIR WILL THEN INFILTRATE FROM WEST TO
EAST...BRINGING AN END TO PRECIP CHANCES ACROSS THE INLAND AREAS. AS
THIS TAKES PLACE...WINDS WILL SHIFT TO A PREDOMINATE NW DIRECTION
AND STRENGTHEN BEHIND THE SHORTWAVE. COLDER H850 TEMPERATURES WILL
THEN BEGIN FILTERING IN BY THE DAY FRIDAY...ALLOWING INSTABILITY AND
LES CHANCES TO DEVELOP.
DAYS 4 THROUGH 7 /FRIDAY NIGHT THROUGH TUESDAY/...
AS THE GENERAL TROUGH PATTERN CONTINUES OVER THE NORTHEASTERN CONUS
THROUGH THE WEEKEND...EXPECT A SERIES OF SHORTWAVES TO IMPACT THE
UPPER GREAT LAKES DURING THIS TIME PERIOD. MODELS WILL CONTINUE
HAVING VARYING SOLUTIONS ON TIMING AND LOCATION...WITH THE ECMWF
CONTINUING TO BE THE MOST PROGRESSIVE.
LES CHANCES WILL CONTINUE FRIDAY NIGHT AND THEN DURING THE DAY
SATURDAY WITH 0Z ECMWF H850 TEMPS -15C ACROSS LAKE SUPERIOR AND
PREDOMINATE NW WINDS DURING THE DAY. LINGERING LOW LEVEL MOISTURE
WILL HELP KEEP LES EAST OF MUNISING WHERE NW WINDS WILL BE MAXIMIZED
WITH THE FETCH OVER THE LAKE. INVERSION HEIGHTS WILL BE AROUND
6KFT...WITH THE BEST SNOW GROWTH JUST BELOW THIS LAYER. CAPE VALUES
WILL MAX OUT AROUND 18Z SATURDAY...AS WILL THE LES PARAMETER. WITH
LIGHT TO MODERATE WINDS...COULD EXPECT HIGHER END SNOW RATIOS IN THE
UPPER TEENS TO LOW 20S. WILL CONTINUE WITH MIDNIGHT SHIFTS DECISION
TO BUMP UP POPS IN NW WIND FAVORED AREAS DURING THIS TIME PERIOD. AS
NEXT SHORTWAVE PASSES OVER SATURDAY NIGHT...EXPECT WINDS TO THEN
SHIFT TO A MORE WESTERLY DIRECTION AND H850 TEMPS TO BEGIN
INCREASING BY SUNDAY EVENING...THEREBY BRINGING AN END TO ANY
LINGERING LES CHANCES. 0Z ECMWF/GFS THEN HAVE A SHORT LIVED RIDGE
BUILDING IN ON MONDAY KEEPING CONDITIONS DRY DURING THE DAY.
DECREASING CLOUDS DURING THIS TIME PERIOD SHOULD ALLOW HIGH
TEMPERATURES TO RISE BACK INTO THE MID 30S.
AS RIDGE LIES OVER THE UPPER GREAT LAKES ON MONDAY...A SHORTWAVE
WILL BEGIN DEVELOPING OVER THE PLAINS. THIS WILL AMPLIFY THE
RIDGE...WHILE ALSO CAUSING ITS QUICK EXIT TO THE NORTHEAST.
SHORTWAVE WILL THEN REPLACE THE RIDGE AND BRING PRECIP CHANCES BY
MONDAY NIGHT...WITH THE 0Z ECMWF KEEPING THE TRACK OF THIS SHORTWAVE
ACROSS WI AND LOWER MI. WITH INCREASED CLOUD COVER AHEAD OF THIS
SYSTEM...DON/T EXPECT LOW TEMPERATURES TO DROP MUCH...REMAINING IN
THE 20S. ASSOCIATED LOW PRESSURE WILL REACH CROSS UPPER MI BY
TUESDAY AFTERNOON...WITH PRECIP CHANCES CONTINUING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM EST TUE FEB 14 2012
EXTENSIVE LOW LEVEL MOISTURE OVER UPPER MICHIGAN IS EXPECTED TO
PERSIST THIS AFTERNOON INTO THIS EVENING...PER UPSTREAM OBS AND
NAM/RUC 925-850 MB MOISTURE FCST. SO...MAINLY MVFR CIGS SHOULD PREVAIL.
VFR CIGS EARLY THIS AFTERNOON AT KSAW ARE EXPECTED TO GIVE WAY TO
MVFR CIGS FROM THE WEST BY MID AFTERNOON. ANOTHER LOW PRES SYSTEM
APPROACHING FROM THE NRN PLAINS LATE TONIGHT SHOULD CONTINUE TO KEEP
MVFR CIGS ACROSS THE REGION. THERE COULD BE A CHANCE OF SOME LIGHT
SNOW LATE TONIGHT INTO EARLY WED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EST TUE FEB 14 2012
A SERIES OF WEAK LOW PRESSURE TROUGHS MOVING THROUGH THE AREA WILL
KEEP WINDS BELOW 20KTS TONIGHT THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE
THROUGH THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JMW
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1243 PM EST TUE FEB 14 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST TUE FEB 14 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED MID/UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE MID-MISSISSIPPI VALLEY EARLY THIS
MORNING WITH CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON
THE PERIPHERY OF THE DEEP TROUGH OVER ERN CANADA. LATEST RADAR
IMAGERY SHOWED THAT THE NRN EDGE OF THE PCPN SHIELD WITH THIS SYSTEM
HAD ADVANCED INTO SCNTRL AND ERN UPR MI WITH SFC OBS INDICATING LIGHT
SNOW OR FLURRIES. AT THE SFC...A MOIST SRLY FLOW PREVAILED FROM MO/IA
INTO WI AND UPPER MI AHEAD OF A TROUGH OVER THE PLAINS. IR SATELLITE
REVEALED EXTENSIVE LOW TO MID CLOUD COVER ACROSS THE MIDWEST AND
GREAT LAKES REGION ASSOC WITH THE SHORTWAVE.
TODAY...EXPECT LIGHT SNOW OVER SCNTRL AND ERN COUNTIES TO DIMINISH
OR END THROUGH THE MORNING HOURS AS SUPPORTING 700-600 MB FGEN
FORCING WEAKENS AND SHIFTS EAST WITH DEPARTING SHORTWAVE. NAM/GFS
BUFR SNDGS SUGGEST LOW-LVL MOISTURE AND CLOUDS WILL REMAIN THROUGH
THE DAY EVEN AFTER THE SNOW ENDS. HOWEVER...MAX READINGS SHOULD
STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE LINGERING CLOUDS.
TONIGHT...ANOTHER SHORTWAVE NOW OVER THE DAKOTAS IS EXPECTED MOVE
EAST REACHING THE UPPER GREAT LAKES LATE TONIGHT. MODEST 285K
ISENTROPIC ASCENT AND LOWERING OF CONDENSATION PRES DEFICITS ASSOC
WITH THIS FEATURE COULD RESULT IN A LITTLE LIGHT SNOW OR FLURRIES
LATE TONIGHT INTO WED. SINCE RADAR IS ONLY SHOWING ISOLD TO SCT
COVERAGE UPSTREAM WILL ONLY INCLUDE SLIGHT CHC POPS FOR LATE TONIGHT
OVER MAINLY WRN AND CENTRAL PORTIONS OF THE CWA. LOOK FOR MINS
TONIGHT TO RANGE MAINLY IN THE LOWER 20S OVER THE WRN INTERIOR TO
THE MID 20S NEAR THE GREAT LAKES AND EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 458 AM EST TUE FEB 14 2012
WEAK SHORTWAVE WILL BE MOVING THROUGH THE CWA WED MORNING. WITH THE
SHORTWAVE...DECENT H925-700 MOISTURE...AND H850-700
Q-VECTOR CONV THINK THERE IS A POTENTIAL FOR A FEW LIGHT SNOW
SHOWERS MOVING FROM W TO E ACROSS THE CWA IN THE MORNING AND EARLY
AFTN. THUS...ADDED SLIGHT CHANCES INTO THE FORECAST BUT DON/T
REALLY EXPECT MUCH IF ANY ACCUM. AS THE SHORTWAVE MOVES E THROUGH
THE DAY...STRONGER NRN STREAM SHORTWAVE WILL BE MOVING OUT OF THE
DAKOTAS AND INTO MN. BRIEF PERIOD OF DRYING BEHIND THE DISTURBANCE
COULD LEAD TO SOME BREAKS IN THE CLOUDS. THESE BREAKS WILL
LARGELY DEPEND ON IF MOISTURE REMAINS TRAPPED BELOW THE 1.5-3KFT
INVERSION FROM THE WAA AND DRYING ALOFT. THINK IT SHOULD STICK
AROUND AND WILL KEEP SKIES MOSTLY CLOUDY.
LAND AREA WILL LIKELY BE BETWEEN SYSTEMS ON WED EVENING. NRN STREAM
ENERGY SHORTWAVE AND APPROACHING SFC TROUGH FROM LOW IN CNTRL CANADA
WILL LEAD TO A GLANCING BLOW OVER THE NW HALF OF LK SUPERIOR.
MEANWHILE...SRN STREAM ENERGY AND LOW WILL BE PUSHING OUT OF THE
CNTRL PLAINS. DID START TO INCREASE POPS THROUGH THE OVERNIGHT
HOURS...AS SFC TROUGH BEGINS TO SLIDE INTO THE AREA AND H850-500
Q-VECTOR CONV AND MOISTURE INCREASES. BEST CHANCES WILL BE OVER NRN
LK SUPERIOR CLOSER TO THE NRN STREAM SHORTWAVE AND OVER SCNTRL
UPPER MI CLOSER TO THE SFC LOW MOVING INTO THE LOWER GREAT LKS.
MODEL DIFFERENCES REALLY BECOME APPARENT HEADING INTO
THURSDAY...WITH NAM/GFS IN ONE CAMP AND THE ECMWF/UKMET/GEM IN
THE OTHER. THIS IS NORMALLY THE CASE IN PHASING OF NRN/SRN STREAM
SYSTEMS AND LEAVES LOW CONF IN THE FCST. THE NAM/GFS HAVE A MUCH
STRONGER/SHARPER NRN STREAM WAVE AND THUS ENDS UP DOMINATING THE
PHASING AND KEEPS THE LOW ASSOCIATED WITH THE SRN STREAM SUPPRESSED
AND JUST SWEEPS THE SFC TROUGH ACROSS THE AREA. THE 00Z NAM
ACTUALLY DOESN/T BRING ANY PCPN TO THE AREA...WHILE THE 00Z GFS
ONLY BRINGS A FEW HUNDREDTHS. THE OTHER GROUPING HAS A WEAKER NRN
STREAM AND ALLOWS SRN STREAM TO TRACK A MID 1000S SFC LOW FROM THE
CNTRL PLAINS ON WED INTO THE LOWER GREAT LKS BY THURS AFTN. OVERALL
CONSENSUS WITH THESE MODELS IS TO HAVE THE LOW TRACK NEAR
DETROIT...ALTHOUGH THE 00Z GEM HAS SLID THE LOW FARTHER TO THE NW
AND IN CNTRL LOWER MI. 21Z SREF EVEN SHOWING THESE DIFFERENCES
WITH THE ENS MEAN SFC TRACKING THROUGH CNTRL LOWER MI.
LOOKING AT THE INDIVIDUAL MEMBERS...THERE IS A LARGE
CLUSTER OF WRF ARW/NMM MEMBERS HAVING THE LOW IN CNTRL LOWER
MI...WHILE THE ETA/RSM MEMBERS KEEP IT IN THE OHIO RIVER VALLEY.
HPC PREFERS THE WEAKER NRN STREAM SOLN...SO HAVE FOLLOWED THAT FOR
THURS.
WITH THE PREFERENCE TOWARDS THE ECMWF SOLN...EXPECT AREA OF SNOW TO
QUICKLY SLIDE ACROSS THE SE HALF OF THE CWA THURS MORN AND INTO
EARLY AFTN. DECENT H850-700 Q-VECTOR CONV AND MOISTURE OVER THE
AREA...BUT THE BETTER WAA STAYS SE OF THE AREA AND CLOSER TO THE
LOW. DEPENDING ON THE EXACT TRACK OF THE LOW...SNOW AMNTS WILL
FLUCTUATE TO THE NW OR SE BUT CURRENTLY HAVE 1-3IN ALONG THE LK MI
SHORELINE. ALSO ADJUSTED THE EXISTING LIKELYS OVER PORTIONS OF THE
ERN CWA TO LINE UP ALONG THE LK MI SHORELINE AND JUST HAVE CHANCES
ELSEWHERE. WITH THE LOW CONF ON OCCURRENCE AND SUB ADVY
VALUES...WILL LEAVE MENTION OUT OF THE HWO. AS THE ENERGY SLIDES ENE
DURING THE AFTN...SHOULD SEE A DIMINISHING TREND FROM W TO E IN THE
PCPN. COLDER AIR WILL START TO FILTER IN BEHIND THE LOW/TROUGH AND
COULD LEAD TO SOME LK EFFECT PCPN AS H850 TEMPS FALL TOWARDS -10C BY
00Z FRI. LINGERED SOME CHANCES OVER THE FAR WRN CWA TO ACCOUNT FOR
THIS.
H850 TEMPS WILL GRADUALLY FALL TOWARDS -12C THURS NIGHT. WITH WNW
WINDS...HAVE CHANCE LES POPS IN AREAS FAVORED BY THAT WIND
DIRECTION. BUFKIT SOUNDINGS SHOWING WELL MIXED LLVLS WHICH SHOULD
LIMIT INTENSITY OF THE BANDS.
DAYS 4 THROUGH 7 /FRIDAY THROUGH MONDAY/...
NEXT SHORTWAVE MOVING AROUND THE UPPER LOW STATIONED OVER ERN
CANADA WILL IMPACT THE AREA ON FRI. STILL DECENT DIFFERENCES IN THE
INTENSITY/LOCATION OF THE WAVE...BUT IT SHOULD PULL ADDITIONAL
MOISTURE INTO THE AREA AND PROVIDE AN UPTICK IN THE ONGOING LES. NOT
A WHOLE LOT OF AGREEMENT HEADING THE REST OF THE WAY THROUGH THE
EXTENDED FORECAST PERIOD...AS EXTENDED MODELS CONTINUE TO STRUGGLE
WITH THE NRN/SRN STREAMS COMING TOGETHER OVER THE NEW ENGLAND
STATES. LIKELY WILL SEE NW FLOW ALOFT AND THE POTENTIAL FOR
SHORTWAVES TO MOVE ACROSS THE AREA.
CONTINUED LES CHANCES FOR NW WINDS FAVORED LOCATIONS FRI NIGHT INTO
SAT NIGHT. H850 TEMPS PEAK AROUND -15C ON FRI NIGHT INTO SAT MORNING
AND THEN GRADUALLY WARM THROUGH THE REST OF THE WEEKEND. WITH
DECENT LLVL MOISTURE AT THAT TIME AND INVERSION HEIGHTS AROUND
5KFT...EXPECT LIGHT TO MODERATE LES TO CONTINUE FOR NW WIND
FAVORED LOCATIONS. MUCH OF THE LES CLOUD SHOULD BE WITHIN THE
DGZ...SO THE POTENTIAL EXISTS FOR NEAR ADVY CRITERIA SNOW
AMNTS FRI NIGHT INTO SAT. BEST CHANCE WOULD BE E OF MUNISING
WHERE THE LONGER FETCH WILL AID INTENSITY. HAVE BUMPED POPS UP
SIGNIFICANTLY IN THAT AREA TO HIGH END CHANCES. AS H850 TEMPS SLOWLY
WARM AND DRIER AIR STARTS TO ARRIVE...TAPERED POPS DOWN SAT NIGHT
INTO SUN. H850 RIDGE WILL LIKELY MOVE OVER THE CWA HEADING INTO
MON...BRINGING WARMER H850 TEMPS AND DRIER AIR. OVERALL TEMPS LOOK
TO REMAIN NORMAL TO ABOVE NORMAL THROUGH THE FIRST PART OF NEXT
WEEK WITH NO MAJOR SNOW EVENTS ON THE HORIZON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM EST TUE FEB 14 2012
EXTENSIVE LOW LEVEL MOISTURE OVER UPPER MICHIGAN IS EXPECTED TO
PERSIST THIS AFTERNOON INTO THIS EVENING...PER UPSTREAM OBS AND
NAM/RUC 925-850 MB MOISTURE FCST. SO...MAINLY MVFR CIGS SHOULD PREVAIL.
VFR CIGS EARLY THIS AFTERNOON AT KSAW ARE EXPECTED TO GIVE WAY TO
MVFR CIGS FROM THE WEST BY MID AFTERNOON. ANOTHER LOW PRES SYSTEM
APPROACHING FROM THE NRN PLAINS LATE TONIGHT SHOULD CONTINUE TO KEEP
MVFR CIGS ACROSS THE REGION. THERE COULD BE A CHANCE OF SOME LIGHT
SNOW LATE TONIGHT INTO EARLY WED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST TUE FEB 14 2012
A SERIES OF WEAK LOW PRESSURE TROUGHS MOVING THROUGH THE AREA WILL
KEEP WINDS BELOW 20KTS TODAY THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE
THROUGH THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
716 AM EST TUE FEB 14 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST TUE FEB 14 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED MID/UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE MID-MISSISSIPPI VALLEY EARLY THIS
MORNING WITH CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON
THE PERIPHERY OF THE DEEP TROUGH OVER ERN CANADA. LATEST RADAR
IMAGERY SHOWED THAT THE NRN EDGE OF THE PCPN SHIELD WITH THIS SYSTEM
HAD ADVANCED INTO SCNTRL AND ERN UPR MI WITH SFC OBS INDICATING LIGHT
SNOW OR FLURRIES. AT THE SFC...A MOIST SRLY FLOW PREVAILED FROM MO/IA
INTO WI AND UPPER MI AHEAD OF A TROUGH OVER THE PLAINS. IR SATELLITE
REVEALED EXTENSIVE LOW TO MID CLOUD COVER ACROSS THE MIDWEST AND
GREAT LAKES REGION ASSOC WITH THE SHORTWAVE.
TODAY...EXPECT LIGHT SNOW OVER SCNTRL AND ERN COUNTIES TO DIMINISH
OR END THROUGH THE MORNING HOURS AS SUPPORTING 700-600 MB FGEN
FORCING WEAKENS AND SHIFTS EAST WITH DEPARTING SHORTWAVE. NAM/GFS
BUFR SNDGS SUGGEST LOW-LVL MOISTURE AND CLOUDS WILL REMAIN THROUGH
THE DAY EVEN AFTER THE SNOW ENDS. HOWEVER...MAX READINGS SHOULD
STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE LINGERING CLOUDS.
TONIGHT...ANOTHER SHORTWAVE NOW OVER THE DAKOTAS IS EXPECTED MOVE
EAST REACHING THE UPPER GREAT LAKES LATE TONIGHT. MODEST 285K
ISENTROPIC ASCENT AND LOWERING OF CONDENSATION PRES DEFICITS ASSOC
WITH THIS FEATURE COULD RESULT IN A LITTLE LIGHT SNOW OR FLURRIES
LATE TONIGHT INTO WED. SINCE RADAR IS ONLY SHOWING ISOLD TO SCT
COVERAGE UPSTREAM WILL ONLY INCLUDE SLIGHT CHC POPS FOR LATE TONIGHT
OVER MAINLY WRN AND CENTRAL PORTIONS OF THE CWA. LOOK FOR MINS
TONIGHT TO RANGE MAINLY IN THE LOWER 20S OVER THE WRN INTERIOR TO
THE MID 20S NEAR THE GREAT LAKES AND EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 458 AM EST TUE FEB 14 2012
WEAK SHORTWAVE WILL BE MOVING THROUGH THE CWA WED MORNING. WITH THE
SHORTWAVE...DECENT H925-700 MOISTURE...AND H850-700
Q-VECTOR CONV THINK THERE IS A POTENTIAL FOR A FEW LIGHT SNOW
SHOWERS MOVING FROM W TO E ACROSS THE CWA IN THE MORNING AND EARLY
AFTN. THUS...ADDED SLIGHT CHANCES INTO THE FORECAST BUT DON/T
REALLY EXPECT MUCH IF ANY ACCUM. AS THE SHORTWAVE MOVES E THROUGH
THE DAY...STRONGER NRN STREAM SHORTWAVE WILL BE MOVING OUT OF THE
DAKOTAS AND INTO MN. BRIEF PERIOD OF DRYING BEHIND THE DISTURBANCE
COULD LEAD TO SOME BREAKS IN THE CLOUDS. THESE BREAKS WILL
LARGELY DEPEND ON IF MOISTURE REMAINS TRAPPED BELOW THE 1.5-3KFT
INVERSION FROM THE WAA AND DRYING ALOFT. THINK IT SHOULD STICK
AROUND AND WILL KEEP SKIES MOSTLY CLOUDY.
LAND AREA WILL LIKELY BE BETWEEN SYSTEMS ON WED EVENING. NRN STREAM
ENERGY SHORTWAVE AND APPROACHING SFC TROUGH FROM LOW IN CNTRL CANADA
WILL LEAD TO A GLANCING BLOW OVER THE NW HALF OF LK SUPERIOR.
MEANWHILE...SRN STREAM ENERGY AND LOW WILL BE PUSHING OUT OF THE
CNTRL PLAINS. DID START TO INCREASE POPS THROUGH THE OVERNIGHT
HOURS...AS SFC TROUGH BEGINS TO SLIDE INTO THE AREA AND H850-500
Q-VECTOR CONV AND MOISTURE INCREASES. BEST CHANCES WILL BE OVER NRN
LK SUPERIOR CLOSER TO THE NRN STREAM SHORTWAVE AND OVER SCNTRL
UPPER MI CLOSER TO THE SFC LOW MOVING INTO THE LOWER GREAT LKS.
MODEL DIFFERENCES REALLY BECOME APPARENT HEADING INTO
THURSDAY...WITH NAM/GFS IN ONE CAMP AND THE ECMWF/UKMET/GEM IN
THE OTHER. THIS IS NORMALLY THE CASE IN PHASING OF NRN/SRN STREAM
SYSTEMS AND LEAVES LOW CONF IN THE FCST. THE NAM/GFS HAVE A MUCH
STRONGER/SHARPER NRN STREAM WAVE AND THUS ENDS UP DOMINATING THE
PHASING AND KEEPS THE LOW ASSOCIATED WITH THE SRN STREAM SUPPRESSED
AND JUST SWEEPS THE SFC TROUGH ACROSS THE AREA. THE 00Z NAM
ACTUALLY DOESN/T BRING ANY PCPN TO THE AREA...WHILE THE 00Z GFS
ONLY BRINGS A FEW HUNDREDTHS. THE OTHER GROUPING HAS A WEAKER NRN
STREAM AND ALLOWS SRN STREAM TO TRACK A MID 1000S SFC LOW FROM THE
CNTRL PLAINS ON WED INTO THE LOWER GREAT LKS BY THURS AFTN. OVERALL
CONSENSUS WITH THESE MODELS IS TO HAVE THE LOW TRACK NEAR
DETROIT...ALTHOUGH THE 00Z GEM HAS SLID THE LOW FARTHER TO THE NW
AND IN CNTRL LOWER MI. 21Z SREF EVEN SHOWING THESE DIFFERENCES
WITH THE ENS MEAN SFC TRACKING THROUGH CNTRL LOWER MI.
LOOKING AT THE INDIVIDUAL MEMBERS...THERE IS A LARGE
CLUSTER OF WRF ARW/NMM MEMBERS HAVING THE LOW IN CNTRL LOWER
MI...WHILE THE ETA/RSM MEMBERS KEEP IT IN THE OHIO RIVER VALLEY.
HPC PREFERS THE WEAKER NRN STREAM SOLN...SO HAVE FOLLOWED THAT FOR
THURS.
WITH THE PREFERENCE TOWARDS THE ECMWF SOLN...EXPECT AREA OF SNOW TO
QUICKLY SLIDE ACROSS THE SE HALF OF THE CWA THURS MORN AND INTO
EARLY AFTN. DECENT H850-700 Q-VECTOR CONV AND MOISTURE OVER THE
AREA...BUT THE BETTER WAA STAYS SE OF THE AREA AND CLOSER TO THE
LOW. DEPENDING ON THE EXACT TRACK OF THE LOW...SNOW AMNTS WILL
FLUCTUATE TO THE NW OR SE BUT CURRENTLY HAVE 1-3IN ALONG THE LK MI
SHORELINE. ALSO ADJUSTED THE EXISTING LIKELYS OVER PORTIONS OF THE
ERN CWA TO LINE UP ALONG THE LK MI SHORELINE AND JUST HAVE CHANCES
ELSEWHERE. WITH THE LOW CONF ON OCCURRENCE AND SUB ADVY
VALUES...WILL LEAVE MENTION OUT OF THE HWO. AS THE ENERGY SLIDES ENE
DURING THE AFTN...SHOULD SEE A DIMINISHING TREND FROM W TO E IN THE
PCPN. COLDER AIR WILL START TO FILTER IN BEHIND THE LOW/TROUGH AND
COULD LEAD TO SOME LK EFFECT PCPN AS H850 TEMPS FALL TOWARDS -10C BY
00Z FRI. LINGERED SOME CHANCES OVER THE FAR WRN CWA TO ACCOUNT FOR
THIS.
H850 TEMPS WILL GRADUALLY FALL TOWARDS -12C THURS NIGHT. WITH WNW
WINDS...HAVE CHANCE LES POPS IN AREAS FAVORED BY THAT WIND
DIRECTION. BUFKIT SOUNDINGS SHOWING WELL MIXED LLVLS WHICH SHOULD
LIMIT INTENSITY OF THE BANDS.
DAYS 4 THROUGH 7 /FRIDAY THROUGH MONDAY/...
NEXT SHORTWAVE MOVING AROUND THE UPPER LOW STATIONED OVER ERN
CANADA WILL IMPACT THE AREA ON FRI. STILL DECENT DIFFERENCES IN THE
INTENSITY/LOCATION OF THE WAVE...BUT IT SHOULD PULL ADDITIONAL
MOISTURE INTO THE AREA AND PROVIDE AN UPTICK IN THE ONGOING LES. NOT
A WHOLE LOT OF AGREEMENT HEADING THE REST OF THE WAY THROUGH THE
EXTENDED FORECAST PERIOD...AS EXTENDED MODELS CONTINUE TO STRUGGLE
WITH THE NRN/SRN STREAMS COMING TOGETHER OVER THE NEW ENGLAND
STATES. LIKELY WILL SEE NW FLOW ALOFT AND THE POTENTIAL FOR
SHORTWAVES TO MOVE ACROSS THE AREA.
CONTINUED LES CHANCES FOR NW WINDS FAVORED LOCATIONS FRI NIGHT INTO
SAT NIGHT. H850 TEMPS PEAK AROUND -15C ON FRI NIGHT INTO SAT MORNING
AND THEN GRADUALLY WARM THROUGH THE REST OF THE WEEKEND. WITH
DECENT LLVL MOISTURE AT THAT TIME AND INVERSION HEIGHTS AROUND
5KFT...EXPECT LIGHT TO MODERATE LES TO CONTINUE FOR NW WIND
FAVORED LOCATIONS. MUCH OF THE LES CLOUD SHOULD BE WITHIN THE
DGZ...SO THE POTENTIAL EXISTS FOR NEAR ADVY CRITERIA SNOW
AMNTS FRI NIGHT INTO SAT. BEST CHANCE WOULD BE E OF MUNISING
WHERE THE LONGER FETCH WILL AID INTENSITY. HAVE BUMPED POPS UP
SIGNIFICANTLY IN THAT AREA TO HIGH END CHANCES. AS H850 TEMPS SLOWLY
WARM AND DRIER AIR STARTS TO ARRIVE...TAPERED POPS DOWN SAT NIGHT
INTO SUN. H850 RIDGE WILL LIKELY MOVE OVER THE CWA HEADING INTO
MON...BRINGING WARMER H850 TEMPS AND DRIER AIR. OVERALL TEMPS LOOK
TO REMAIN NORMAL TO ABOVE NORMAL THROUGH THE FIRST PART OF NEXT
WEEK WITH NO MAJOR SNOW EVENTS ON THE HORIZON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 716 AM EST TUE FEB 14 2012
EXTENSIVE LOW CLOUD COVER ASSOC WITH THE LOW PRES SYSTEM MOVING
THROUGH THE OHIO VALLEY WILL KEEP MOST OF THE TAF SITES UNDER MVFR
CIGS TODAY. ANOTHER LOW PRES SYSTEM APPROACHING FROM THE NRN PLAINS
LATE TONIGHT SHOULD CONTINUE TO KEEP MVFR CIGS ACROSS THE REGION.
THERE COULD BE A CHANCE OF SOME LIGHT SNOW BTWN 09-12Z AT KCMX AND
KIWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST TUE FEB 14 2012
A SERIES OF WEAK LOW PRESSURE TROUGHS MOVING THROUGH THE AREA WILL
KEEP WINDS BELOW 20KTS TODAY THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE
THROUGH THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION...CORRECTED
NWS MARQUETTE MI
508 AM EST TUE FEB 14 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST TUE FEB 14 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED MID/UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE MID-MISSISSIPPI VALLEY EARLY THIS
MORNING WITH CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON
THE PERIPHERY OF THE DEEP TROUGH OVER ERN CANADA. LATEST RADAR
IMAGERY SHOWED THAT THE NRN EDGE OF THE PCPN SHIELD WITH THIS SYSTEM
HAD ADVANCED INTO SCNTRL AND ERN UPR MI WITH SFC OBS INDICATING LIGHT
SNOW OR FLURRIES. AT THE SFC...A MOIST SRLY FLOW PREVAILED FROM MO/IA
INTO WI AND UPPER MI AHEAD OF A TROUGH OVER THE PLAINS. IR SATELLITE
REVEALED EXTENSIVE LOW TO MID CLOUD COVER ACROSS THE MIDWEST AND
GREAT LAKES REGION ASSOC WITH THE SHORTWAVE.
TODAY...EXPECT LIGHT SNOW OVER SCNTRL AND ERN COUNTIES TO DIMINISH
OR END THROUGH THE MORNING HOURS AS SUPPORTING 700-600 MB FGEN
FORCING WEAKENS AND SHIFTS EAST WITH DEPARTING SHORTWAVE. NAM/GFS
BUFR SNDGS SUGGEST LOW-LVL MOISTURE AND CLOUDS WILL REMAIN THROUGH
THE DAY EVEN AFTER THE SNOW ENDS. HOWEVER...MAX READINGS SHOULD
STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE LINGERING CLOUDS.
TONIGHT...ANOTHER SHORTWAVE NOW OVER THE DAKOTAS IS EXPECTED MOVE
EAST REACHING THE UPPER GREAT LAKES LATE TONIGHT. MODEST 285K
ISENTROPIC ASCENT AND LOWERING OF CONDENSATION PRES DEFICITS ASSOC
WITH THIS FEATURE COULD RESULT IN A LITTLE LIGHT SNOW OR FLURRIES
LATE TONIGHT INTO WED. SINCE RADAR IS ONLY SHOWING ISOLD TO SCT
COVERAGE UPSTREAM WILL ONLY INCLUDE SLIGHT CHC POPS FOR LATE TONIGHT
OVER MAINLY WRN AND CENTRAL PORTIONS OF THE CWA. LOOK FOR MINS
TONIGHT TO RANGE MAINLY IN THE LOWER 20S OVER THE WRN INTERIOR TO
THE MID 20S NEAR THE GREAT LAKES AND EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 458 AM EST TUE FEB 14 2012
WEAK SHORTWAVE WILL BE MOVING THROUGH THE CWA WED MORNING. WITH THE
SHORTWAVE...DECENT H925-700 MOISTURE...AND H850-700
Q-VECTOR CONV THINK THERE IS A POTENTIAL FOR A FEW LIGHT SNOW
SHOWERS MOVING FROM W TO E ACROSS THE CWA IN THE MORNING AND EARLY
AFTN. THUS...ADDED SLIGHT CHANCES INTO THE FORECAST BUT DON/T
REALLY EXPECT MUCH IF ANY ACCUM. AS THE SHORTWAVE MOVES E THROUGH
THE DAY...STRONGER NRN STREAM SHORTWAVE WILL BE MOVING OUT OF THE
DAKOTAS AND INTO MN. BRIEF PERIOD OF DRYING BEHIND THE DISTURBANCE
COULD LEAD TO SOME BREAKS IN THE CLOUDS. THESE BREAKS WILL
LARGELY DEPEND ON IF MOISTURE REMAINS TRAPPED BELOW THE 1.5-3KFT
INVERSION FROM THE WAA AND DRYING ALOFT. THINK IT SHOULD STICK
AROUND AND WILL KEEP SKIES MOSTLY CLOUDY.
LAND AREA WILL LIKELY BE BETWEEN SYSTEMS ON WED EVENING. NRN STREAM
ENERGY SHORTWAVE AND APPROACHING SFC TROUGH FROM LOW IN CNTRL CANADA
WILL LEAD TO A GLANCING BLOW OVER THE NW HALF OF LK SUPERIOR.
MEANWHILE...SRN STREAM ENERGY AND LOW WILL BE PUSHING OUT OF THE
CNTRL PLAINS. DID START TO INCREASE POPS THROUGH THE OVERNIGHT
HOURS...AS SFC TROUGH BEGINS TO SLIDE INTO THE AREA AND H850-500
Q-VECTOR CONV AND MOISTURE INCREASES. BEST CHANCES WILL BE OVER NRN
LK SUPERIOR CLOSER TO THE NRN STREAM SHORTWAVE AND OVER SCNTRL
UPPER MI CLOSER TO THE SFC LOW MOVING INTO THE LOWER GREAT LKS.
MODEL DIFFERENCES REALLY BECOME APPARENT HEADING INTO
THURSDAY...WITH NAM/GFS IN ONE CAMP AND THE ECMWF/UKMET/GEM IN
THE OTHER. THIS IS NORMALLY THE CASE IN PHASING OF NRN/SRN STREAM
SYSTEMS AND LEAVES LOW CONF IN THE FCST. THE NAM/GFS HAVE A MUCH
STRONGER/SHARPER NRN STREAM WAVE AND THUS ENDS UP DOMINATING THE
PHASING AND KEEPS THE LOW ASSOCIATED WITH THE SRN STREAM SUPPRESSED
AND JUST SWEEPS THE SFC TROUGH ACROSS THE AREA. THE 00Z NAM
ACTUALLY DOESN/T BRING ANY PCPN TO THE AREA...WHILE THE 00Z GFS
ONLY BRINGS A FEW HUNDREDTHS. THE OTHER GROUPING HAS A WEAKER NRN
STREAM AND ALLOWS SRN STREAM TO TRACK A MID 1000S SFC LOW FROM THE
CNTRL PLAINS ON WED INTO THE LOWER GREAT LKS BY THURS AFTN. OVERALL
CONSENSUS WITH THESE MODELS IS TO HAVE THE LOW TRACK NEAR
DETROIT...ALTHOUGH THE 00Z GEM HAS SLID THE LOW FARTHER TO THE NW
AND IN CNTRL LOWER MI. 21Z SREF EVEN SHOWING THESE DIFFERENCES
WITH THE ENS MEAN SFC TRACKING THROUGH CNTRL LOWER MI.
LOOKING AT THE INDIVIDUAL MEMBERS...THERE IS A LARGE
CLUSTER OF WRF ARW/NMM MEMBERS HAVING THE LOW IN CNTRL LOWER
MI...WHILE THE ETA/RSM MEMBERS KEEP IT IN THE OHIO RIVER VALLEY.
HPC PREFERS THE WEAKER NRN STREAM SOLN...SO HAVE FOLLOWED THAT FOR
THURS.
WITH THE PREFERENCE TOWARDS THE ECMWF SOLN...EXPECT AREA OF SNOW TO
QUICKLY SLIDE ACROSS THE SE HALF OF THE CWA THURS MORN AND INTO
EARLY AFTN. DECENT H850-700 Q-VECTOR CONV AND MOISTURE OVER THE
AREA...BUT THE BETTER WAA STAYS SE OF THE AREA AND CLOSER TO THE
LOW. DEPENDING ON THE EXACT TRACK OF THE LOW...SNOW AMNTS WILL
FLUCTUATE TO THE NW OR SE BUT CURRENTLY HAVE 1-3IN ALONG THE LK MI
SHORELINE. ALSO ADJUSTED THE EXISTING LIKELYS OVER PORTIONS OF THE
ERN CWA TO LINE UP ALONG THE LK MI SHORELINE AND JUST HAVE CHANCES
ELSEWHERE. WITH THE LOW CONF ON OCCURRENCE AND SUB ADVY
VALUES...WILL LEAVE MENTION OUT OF THE HWO. AS THE ENERGY SLIDES ENE
DURING THE AFTN...SHOULD SEE A DIMINISHING TREND FROM W TO E IN THE
PCPN. COLDER AIR WILL START TO FILTER IN BEHIND THE LOW/TROUGH AND
COULD LEAD TO SOME LK EFFECT PCPN AS H850 TEMPS FALL TOWARDS -10C BY
00Z FRI. LINGERED SOME CHANCES OVER THE FAR WRN CWA TO ACCOUNT FOR
THIS.
H850 TEMPS WILL GRADUALLY FALL TOWARDS -12C THURS NIGHT. WITH WNW
WINDS...HAVE CHANCE LES POPS IN AREAS FAVORED BY THAT WIND
DIRECTION. BUFKIT SOUNDINGS SHOWING WELL MIXED LLVLS WHICH SHOULD
LIMIT INTENSITY OF THE BANDS.
DAYS 4 THROUGH 7 /FRIDAY THROUGH MONDAY/...
NEXT SHORTWAVE MOVING AROUND THE UPPER LOW STATIONED OVER ERN
CANADA WILL IMPACT THE AREA ON FRI. STILL DECENT DIFFERENCES IN THE
INTENSITY/LOCATION OF THE WAVE...BUT IT SHOULD PULL ADDITIONAL
MOISTURE INTO THE AREA AND PROVIDE AN UPTICK IN THE ONGOING LES. NOT
A WHOLE LOT OF AGREEMENT HEADING THE REST OF THE WAY THROUGH THE
EXTENDED FORECAST PERIOD...AS EXTENDED MODELS CONTINUE TO STRUGGLE
WITH THE NRN/SRN STREAMS COMING TOGETHER OVER THE NEW ENGLAND
STATES. LIKELY WILL SEE NW FLOW ALOFT AND THE POTENTIAL FOR
SHORTWAVES TO MOVE ACROSS THE AREA.
CONTINUED LES CHANCES FOR NW WINDS FAVORED LOCATIONS FRI NIGHT INTO
SAT NIGHT. H850 TEMPS PEAK AROUND -15C ON FRI NIGHT INTO SAT MORNING
AND THEN GRADUALLY WARM THROUGH THE REST OF THE WEEKEND. WITH
DECENT LLVL MOISTURE AT THAT TIME AND INVERSION HEIGHTS AROUND
5KFT...EXPECT LIGHT TO MODERATE LES TO CONTINUE FOR NW WIND
FAVORED LOCATIONS. MUCH OF THE LES CLOUD SHOULD BE WITHIN THE
DGZ...SO THE POTENTIAL EXISTS FOR NEAR ADVY CRITERIA SNOW
AMNTS FRI NIGHT INTO SAT. BEST CHANCE WOULD BE E OF MUNISING
WHERE THE LONGER FETCH WILL AID INTENSITY. HAVE BUMPED POPS UP
SIGNIFICANTLY IN THAT AREA TO HIGH END CHANCES. AS H850 TEMPS SLOWLY
WARM AND DRIER AIR STARTS TO ARRIVE...TAPERED POPS DOWN SAT NIGHT
INTO SUN. H850 RIDGE WILL LIKELY MOVE OVER THE CWA HEADING INTO
MON...BRINGING WARMER H850 TEMPS AND DRIER AIR. OVERALL TEMPS LOOK
TO REMAIN NORMAL TO ABOVE NORMAL THROUGH THE FIRST PART OF NEXT
WEEK WITH NO MAJOR SNOW EVENTS ON THE HORIZON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1249 AM EST TUE FEB 14 2012
A DISTURBANCE MOVING FROM THE CNTRAL PLAINS TO THE LOWER GREAT LAKES
WILL CONTINUE TO HAVE THE LOWER CLOUDS LOWER THROUGH THE NIGHT AND
LIKELY BE IN THE MVFR CAT AFTER 09Z AT ALL SITES. ONCE THESE CLOUDS
ARE IN THE MVFR CIG RANGE...THEY WILL STAY THROUGH THE FORECAST
PERIOD AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST TUE FEB 14 2012
A SERIES OF WEAK LOW PRESSURE TROUGHS MOVING THROUGH THE AREA WILL
KEEP WINDS BELOW 20KTS TODAY THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE
THROUGH THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 AM EST TUE FEB 14 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 458 AM EST TUE FEB 14 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED MID/UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE MID-MISSISSIPPI VALLEY EARLY THIS
MORNING WITH CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON
THE PERIPHERY OF THE DEEP TROUGH OVER ERN CANADA. LATEST RADAR
IMAGERY SHOWED THAT THE NRN EDGE OF THE PCPN SHIELD WITH THIS SYSTEM
HAD ADVANCED INTO SCNTRL AND ERN UPR MI WITH SFC OBS INDICATING LIGHT
SNOW OR FLURRIES. AT THE SFC...A MOIST SRLY FLOW PREVAILED FROM MO/IA
INTO WI AND UPPER MI AHEAD OF A TROUGH OVER THE PLAINS. IR SATELLITE
REVEALED EXTENSIVE LOW TO MID CLOUD COVER ACROSS THE MIDWEST AND
GREAT LAKES REGION ASSOC WITH THE SHORTWAVE.
TODAY...EXPECT LIGHT SNOW OVER SCNTRL AND ERN COUNTIES TO DIMINISH
OR END THROUGH THE MORNING HOURS AS SUPPORTING 700-600 MB FGEN
FORCING WEAKENS AND SHIFTS EAST WITH DEPARTING SHORTWAVE. NAM/GFS
BUFR SNDGS SUGGEST LOW-LVL MOISTURE AND CLOUDS WILL REMAIN THROUGH
THE DAY EVEN AFTER THE SNOW ENDS. HOWEVER...MAX READINGS SHOULD
STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE LINGERING CLOUDS.
TONIGHT...ANOTHER SHORTWAVE NOW OVER THE DAKOTAS IS EXPECTED MOVE
EAST REACHING THE UPPER GREAT LAKES LATE TONIGHT. MODEST 285K
ISENTROPIC ASCENT AND LOWERING OF CONDENSATION PRES DEFICITS ASSOC
WITH THIS FEATURE COULD RESULT IN A LITTLE LIGHT SNOW OR FLURRIES
LATE TONIGHT INTO WED. SINCE RADAR IS ONLY SHOWING ISOLD TO SCT
COVERAGE UPSTREAM WILL ONLY INCLUDE SLIGHT CHC POPS FOR LATE TONIGHT
OVER MAINLY WRN AND CENTRAL PORTIONS OF THE CWA. LOOK FOR MINS
TONIGHT TO RANGE MAINLY IN THE LOWER 20S OVER THE WRN INTERIOR TO
THE MID 20S NEAR THE GREAT LAKES AND EAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 458 AM EST TUE FEB 14 2012
WEAK SHORTWAVE WILL BE MOVING THROUGH THE CWA WED MORNING. WITH THE
SHORTWAVE...DECENT H925-700 MOISTURE...AND H850-700
Q-VECTOR CONV THINK THERE IS A POTENTIAL FOR A FEW LIGHT SNOW
SHOWERS MOVING FROM W TO E ACROSS THE CWA IN THE MORNING AND EARLY
AFTN. THUS...ADDED SLIGHT CHANCES INTO THE FORECAST BUT DON/T
REALLY EXPECT MUCH IF ANY ACCUM. AS THE SHORTWAVE MOVES E THROUGH
THE DAY...STRONGER NRN STREAM SHORTWAVE WILL BE MOVING OUT OF THE
DAKOTAS AND INTO MN. BRIEF PERIOD OF DRYING BEHIND THE DISTURBANCE
COULD LEAD TO SOME BREAKS IN THE CLOUDS. THESE BREAKS WILL
LARGELY DEPEND ON IF MOISTURE REMAINS TRAPPED BELOW THE 1.5-3KFT
INVERSION FROM THE WAA AND DRYING ALOFT. THINK IT SHOULD STICK
AROUND AND WILL KEEP SKIES MOSTLY CLOUDY.
LAND AREA WILL LIKELY BE BETWEEN SYSTEMS ON WED EVENING. NRN STREAM
ENERGY SHORTWAVE AND APPROACHING SFC TROUGH FROM LOW IN CNTRL CANADA
WILL LEAD TO A GLANCING BLOW OVER THE NW HALF OF LK SUPERIOR.
MEANWHILE...SRN STREAM ENERGY AND LOW WILL BE PUSHING OUT OF THE
CNTRL PLAINS. DID START TO INCREASE POPS THROUGH THE OVERNIGHT
HOURS...AS SFC TROUGH BEGINS TO SLIDE INTO THE AREA AND H850-500
Q-VECTOR CONV AND MOISTURE INCREASES. BEST CHANCES WILL BE OVER NRN
LK SUPERIOR CLOSER TO THE NRN STREAM SHORTWAVE AND OVER SCNTRL
UPPER MI CLOSER TO THE SFC LOW MOVING INTO THE LOWER GREAT LKS.
MODEL DIFFERENCES REALLY BECOME APPARENT HEADING INTO
THURSDAY...WITH NAM/GFS IN ONE CAMP AND THE ECMWF/UKMET/GEM IN
THE OTHER. THIS IS NORMALLY THE CASE IN PHASING OF NRN/SRN STREAM
SYSTEMS AND LEAVES LOW CONF IN THE FCST. THE NAM/GFS HAVE A MUCH
STRONGER/SHARPER NRN STREAM WAVE AND THUS ENDS UP DOMINATING THE
PHASING AND KEEPS THE LOW ASSOCIATED WITH THE SRN STREAM SUPPRESSED
AND JUST SWEEPS THE SFC TROUGH ACROSS THE AREA. THE 00Z NAM
ACTUALLY DOESN/T BRING ANY PCPN TO THE AREA...WHILE THE 00Z GFS
ONLY BRINGS A FEW HUNDREDTHS. THE OTHER GROUPING HAS A WEAKER NRN
STREAM AND ALLOWS SRN STREAM TO TRACK A MID 1000S SFC LOW FROM THE
CNTRL PLAINS ON WED INTO THE LOWER GREAT LKS BY THURS AFTN. OVERALL
CONSENSUS WITH THESE MODELS IS TO HAVE THE LOW TRACK NEAR
DETROIT...ALTHOUGH THE 00Z GEM HAS SLID THE LOW FARTHER TO THE NW
AND IN CNTRL LOWER MI. 21Z SREF EVEN SHOWING THESE DIFFERENCES
WITH THE ENS MEAN SFC TRACKING THROUGH CNTRL LOWER MI.
LOOKING AT THE INDIVIDUAL MEMBERS...THERE IS A LARGE
CLUSTER OF WRF ARW/NMM MEMBERS HAVING THE LOW IN CNTRL LOWER
MI...WHILE THE ETA/RSM MEMBERS KEEP IT IN THE OHIO RIVER VALLEY.
HPC PREFERS THE WEAKER NRN STREAM SOLN...SO HAVE FOLLOWED THAT FOR
THURS.
WITH THE PREFERENCE TOWARDS THE ECMWF SOLN...EXPECT AREA OF SNOW TO
QUICKLY SLIDE ACROSS THE SE HALF OF THE CWA THURS MORN AND INTO
EARLY AFTN. DECENT H850-700 Q-VECTOR CONV AND MOISTURE OVER THE
AREA...BUT THE BETTER WAA STAYS SE OF THE AREA AND CLOSER TO THE
LOW. DEPENDING ON THE EXACT TRACK OF THE LOW...SNOW AMNTS WILL
FLUCTUATE TO THE NW OR SE BUT CURRENTLY HAVE 1-3IN ALONG THE LK MI
SHORELINE. ALSO ADJUSTED THE EXISTING LIKELYS OVER PORTIONS OF THE
ERN CWA TO LINE UP ALONG THE LK MI SHORELINE AND JUST HAVE CHANCES
ELSEWHERE. WITH THE LOW CONF ON OCCURRENCE AND SUB ADVY
VALUES...WILL LEAVE MENTION OUT OF THE HWO. AS THE ENERGY SLIDES ENE
DURING THE AFTN...SHOULD SEE A DIMINISHING TREND FROM W TO E IN THE
PCPN. COLDER AIR WILL START TO FILTER IN BEHIND THE LOW/TROUGH AND
COULD LEAD TO SOME LK EFFECT PCPN AS H850 TEMPS FALL TOWARDS -10C BY
00Z FRI. LINGERED SOME CHANCES OVER THE FAR WRN CWA TO ACCOUNT FOR
THIS.
H850 TEMPS WILL GRADUALLY FALL TOWARDS -12C THURS NIGHT. WITH WNW
WINDS...HAVE CHANCE LES POPS IN AREAS FAVORED BY THAT WIND
DIRECTION. BUFKIT SOUNDINGS SHOWING WELL MIXED LLVLS WHICH SHOULD
LIMIT INTENSITY OF THE BANDS.
DAYS 4 THROUGH 7 /FRIDAY THROUGH MONDAY/...
NEXT SHORTWAVE MOVING AROUND THE UPPER LOW STATIONED OVER ERN
CANADA WILL IMPACT THE AREA ON FRI. STILL DECENT DIFFERENCES IN THE
INTENSITY/LOCATION OF THE WAVE...BUT IT SHOULD PULL ADDITIONAL
MOISTURE INTO THE AREA AND PROVIDE AN UPTICK IN THE ONGOING LES. NOT
A WHOLE LOT OF AGREEMENT HEADING THE REST OF THE WAY THROUGH THE
EXTENDED FORECAST PERIOD...AS EXTENDED MODELS CONTINUE TO STRUGGLE
WITH THE NRN/SRN STREAMS COMING TOGETHER OVER THE NEW ENGLAND
STATES. LIKELY WILL SEE NW FLOW ALOFT AND THE POTENTIAL FOR
SHORTWAVES TO MOVE ACROSS THE AREA.
CONTINUED LES CHANCES FOR NW WINDS FAVORED LOCATIONS FRI NIGHT INTO
SAT NIGHT. H850 TEMPS PEAK AROUND -15C ON FRI NIGHT INTO SAT MORNING
AND THEN GRADUALLY WARM THROUGH THE REST OF THE WEEKEND. WITH
DECENT LLVL MOISTURE AT THAT TIME AND INVERSION HEIGHTS AROUND
5KFT...EXPECT LIGHT TO MODERATE LES TO CONTINUE FOR NW WIND
FAVORED LOCATIONS. MUCH OF THE LES CLOUD SHOULD BE WITHIN THE
DGZ...SO THE POTENTIAL EXISTS FOR NEAR ADVY CRITERIA SNOW
AMNTS FRI NIGHT INTO SAT. BEST CHANCE WOULD BE E OF MUNISING
WHERE THE LONGER FETCH WILL AID INTENSITY. HAVE BUMPED POPS UP
SIGNIFICANTLY IN THAT AREA TO HIGH END CHANCES. AS H850 TEMPS SLOWLY
WARM AND DRIER AIR STARTS TO ARRIVE...TAPERED POPS DOWN SAT NIGHT
INTO SUN. H850 RIDGE WILL LIKELY MOVE OVER THE CWA HEADING INTO
MON...BRINGING WARMER H850 TEMPS AND DRIER AIR. OVERALL TEMPS LOOK
TO REMAIN NORMAL TO ABOVE NORMAL THROUGH THE FIRST PART OF NEXT
WEEK WITH NO MAJOR SNOW EVENTS ON THE HORIZON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1249 AM EST TUE FEB 14 2012
A DISTURBANCE MOVING FROM THE CNTRAL PLAINS TO THE LOWER GREAT LAKES
WILL CONTINUE TO HAVE THE LOWER CLOUDS LOWER THROUGH THE NIGHT AND
LIKELY BE IN THE MVFR CAT AFTER 09Z AT ALL SITES. ONCE THESE CLOUDS
ARE IN THE MVFR CIG RANGE...THEY WILL STAY THROUGH THE FORECAST
PERIOD AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST TUE FEB 14 2012
A SERIES OF WEAK LOW PRESSURE TROUGHS MOVING THROUGH THE AREA WILL
KEEP WINDS BELOW 20KTS TODAY THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE
THROUGH THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1250 AM EST TUE FEB 14 2012
.UPDATE...
ISSUED AT 1117 PM EST MON FEB 13 2012
JUST A QUICK UPDATE TO PUSH POPS A BIT FURTHER NORTH AS PCPN HAS
GOTTEN FURTHER NORTH THAN PREVIOUS THINKING. IT HAS GOTTEN UP TO
LNL...IMT...ESC AND ISQ NOW. SHOULD NOT GET TOO MUCH FURTHER NORTH
AS IT IS BATTLING SOME DRIER AIR.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 400 PM EST MON FEB 13 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL SHORTWAVE
TROUGH MOVING FROM THE CNTRL PLAINS TOWARD THE MID MS VALLEY AND
CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON THE PERIPHERY OF
THE DEEP TROUGH OVER ERN CANADA. LIGHT SNOW ASSOCIATED WITH THE
SHRTWV HAD ADVANCED INTO SRN WI. AT THE SFC...SRLY FLOW PREVAILED
FROM MO/IA INTO WI UPPER MI AHEAD OF A TROUGH OVER THE PLAINS.
VIS LOOP SHOWED MID CLOUDS HAD SPREAD FROM NRN WI THROUGH THE SW
HALF OF UPPER MI WITH LOW/MID LEVEL MOISTURE ADVECTION AHEAD OF THE
LOW.
TONIGHT INTO TUESDAY...EXPECT CLOUDS TO SPREAD ACROSS THE REST OF
THE CWA LATE THIS AFTERNOON AND PERSIST THROUGH TUESDAY...PER
SATELLITE TRENDS AND NAM/GFS SFC-850 RH FCST. ALTHOUGH THE PCPN OVER
SRN WI CONTINUED TO SPREAD TO THE NORTH...WITH ONLY VERY WEAK FORCING
QVECTOR CONV...FGEN OR ISENTROPIC LIFT...ANY LIGHT SNOW MOVING INTO
THE AREA SHOULD BE VERY LIGHT AND BE CONFINED TO THE FAR SOUTH CWA
(SOUTH OF US-2)...PER GFS/ECMWF AND REGIONAL GEM. CLOUDS WILL HOLD
TEMPS UP TONIGHT WITH MIN READINGS MAINLY IN THE 20S. WITH THE
RELATIVELY MILD AIRMASS LINGERING OVER THE AREA TUESDAY...MAX
READINGS SHOULD STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE
LINGERING CLOUDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 400 PM EST MON FEB 13 2012
WED THRU MON...UNDER SPLIT FLOW REGIME...ARCTIC AIR WILL BE BOTTLED
UP WELL TO THE N INTO NEXT WEEKEND...RESULTING IN TEMPS CONTINUING
TO AVERAGE ABOVE NORMAL. MODELS HINT AT A WEAK SHORTWAVE TO PASS
OVER THE UPPER GREAT LAKES WEDNESDAY. HOWEVER...MID AND UPPER LEVEL
DRY AIR ALONG WITH VERY LITTLE LIFT WILL KEEP MUCH OF UPPER MI
PREDOMINATELY DRY DURING THIS TIME FRAME.
CENTRALIZED SHORTWAVE TRAVERSING CALIFORNIA DURING THE DAY TODAY
WILL SLOWLY MOVE E TO THE CENTRAL PLAINS THROUGH WEDNESDAY...THEN
SHIFT TO A MORE NW DIRECTION...REACHING LAKE MI BY 12Z THURSDAY.
SOME MEDIUM RANGE MODELS ARE ALSO POINTING AT THE POTENTIAL FOR NRN
STREAM ENERGY TO PHASE WITH AND POSSIBLY STRENGTHEN THIS SRN STREAM
SYSTEM AS IT NEARS THE GREAT LAKES REGION. MODEL CONSENSUS KEEPS
MOST OF THE PRECIP CENTERED ALONG EASTERN EDGE OF THE PRESSURE
SYSTEM WHERE THE DEEPEST QVECTOR CONV/LIFT WILL BE LOCATED...AS WELL
AS ALONG THE ADJOINING COLD FRONT TO THE SOUTH. SOME OF THIS DEEP
MOISTURE AND QVECTOR CONV COULD REACH SC AND E UPPER MI DURING THE
DAY THURSDAY...ESPECIALLY AS SYSTEM BECOMES MORE WRAPPED UP. MODELS
HINT AT A TROWEL DEVELOPING...PULLING THE COLD FRONT ACROSS SOUTHERN
MENOMINEE COUNTY AND CENTRAL WI ALONG WITH 0.25 TO 0.5 INCH QPF
VALUES. THIS HAS BEEN CONSISTENT IN THE PREVIOUS TWO RUNS OF THE
GFS/ECMWF/AND NAM...THOUGH LATEST 13/12Z GFS AND GEM SEEMED TO PUSH
PRECIP FARTHER SOUTH. AS A RESULT...HAVE CONTINUED WITH EARLIER
CONSENSUS RUNS AND INCREASED POPS AND QPF ACROSS THE CWA. LATEST
MODEL RUNS ALSO SHOW COLDER 850 TEMPERATURE TRENDS...WHILE SURFACE
TEMPS WILL REMAIN RIGHT AT FREEZING...SO EXPECT SNOW TO BE THE MAIN
PRECIP TYPE. WILL CONTINUE TO MONITOR LATEST MODEL RUNS FOR ANY
CHANGE IN PLACEMENTS/WIND DIRECTIONS AND RESULTING PRECIP
TYPES/LOCATIONS.
MIDLEVEL DRY AIR AHEAD OF APPROACHING RIDGE WILL THEN CUT IN BY
THURSDAY NIGHT AS SHORTWAVE MOVES OFF TO THE NORTHEAST...REDUCING
PRECIP CHANCES FROM WEST TO EAST OVERNIGHT. THE RESULT OF THIS UPPER
LEVEL RIDGING WILL BE TO TURN WINDS MORE NORTHWESTERLY BY FRIDAY
INTO SATURDAY...ALLOWING ARCTIC AIR TO PENETRATE SOUTHWARD ACROSS
THE GREAT LAKES. 13/12Z GFS HAS H850 TEMPS DROPPING TO -17C
SATURDAY. THIS...ALONG WITH LINGERING LOW LEVEL MOISTURE...WILL
CREATE THE CONVERGENCE NEEDED FOR LAKE EFFECT SNOW FRIDAY THROUGH
SATURDAY IN AREAS ALONG LAKE SUPERIOR FAVORED BY NW WINDS. 13/12Z
ECMWF ALSO KEEPS WITH THIS TREND...THOUGH FALLING TEMPERATURES AND
AMOUNT OF CONVERGENCE ARE SLIGHTLY LESS MAGNIFIED. AS A
RESULT...HAVE INCREASED SLIGHT CHANCE TO CHANCE POPS ALONG LAKE
SUPERIOR IN AREAS FAVORED BY A NW WIND DIRECTION...KEEPING WITH
PREVIOUS FORECASTS.
ANY LINGERING LES EAST WILL COME TO AN END LATE SATURDAY...AS WINDS
BECOME MORE SOUTHWESTERLY...AHEAD OF THE NEXT SFC LOW/500MB TROUGH
APPROACHING FROM CENTRAL CANADA AND MN. THERE ARE SIGNIFICANT ENOUGH
TIMING DIFFERENCE TO RESULT IN MODERATE CONFIDENCE IN THE FCST
BEYOND THIS PERIOD. WHILE THE GFS AND ECMWF ARE IN FAIRLY GOOD SHAPE
UP UNTIL THIS POINT...THE 13/06Z RUN OF THE GFS BECOMES ROUGHLY 12
HRS SLOWER THAN THE MORE CONSISTENT ECMWF WITH THE HANDLING OF THIS
WAVE /CENTERED ACROSS THE UPPER GREAT LAKES AT 00Z MONDAY...WHILE
THE ECMWF HAS IT OVER THE LOWER GREAT LAKES/. WHILE THE ECMWF
INDICATES A DRY FRONTAL PASSAGE WITH THE SFC LOW CENTERED OVER
NORTHERN ONTARIO. GIVEN THE SLOWER AND MORE SOUTHERN GFS...A BROAD
SFC LOW WILL LIKELY DEVELOP OVER THE GREAT LAKES...WITH LIGHT PRECIP
AND PLENTY OF CLOUD COVER BEFORE THE SYSTEM EJECTS EASTWARD MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1249 AM EST TUE FEB 14 2012
A DISTURBANCE MOVING FROM THE CNTRAL PLAINS TO THE LOWER GREAT LAKES
WILL CONTINUE TO HAVE THE LOWER CLOUDS LOWER THROUGH THE NIGHT AND
LIKELY BE IN THE MVFR CAT AFTER 09Z AT ALL SITES. ONCE THESE CLOUDS
ARE IN THE MVFR CIG RANGE...THEY WILL STAY THROUGH THE FORECAST
PERIOD AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON FEB 13 2012
A HIGH PRESSURE RIDGE BUILDING OVER THE AREA WILL KEEP WINDS BELOW
20KTS TONIGHT THROUGH WEDNESDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE THROUGH
THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...JMW
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1117 PM EST MON FEB 13 2012
.UPDATE...
ISSUED AT 1117 PM EST MON FEB 13 2012
JUST A QUICK UPDATE TO PUSH POPS A BIT FURTHER NORTH AS PCPN HAS
GOTTEN FURTHER NORTH THAN PREVIOUS THINKING. IT HAS GOTTEN UP TO
LNL...IMT...ESC AND ISQ NOW. SHOULD NOT GET TOO MUCH FURTHER NORTH
AS IT IS BATTLING SOME DRIER AIR.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 400 PM EST MON FEB 13 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL SHORTWAVE
TROUGH MOVING FROM THE CNTRL PLAINS TOWARD THE MID MS VALLEY AND
CONFLUENT FLOW FROM NRN ONTARIO INTO THE NRN LAKES ON THE PERIPHERY OF
THE DEEP TROUGH OVER ERN CANADA. LIGHT SNOW ASSOCIATED WITH THE
SHRTWV HAD ADVANCED INTO SRN WI. AT THE SFC...SRLY FLOW PREVAILED
FROM MO/IA INTO WI UPPER MI AHEAD OF A TROUGH OVER THE PLAINS.
VIS LOOP SHOWED MID CLOUDS HAD SPREAD FROM NRN WI THROUGH THE SW
HALF OF UPPER MI WITH LOW/MID LEVEL MOISTURE ADVECTION AHEAD OF THE
LOW.
TONIGHT INTO TUESDAY...EXPECT CLOUDS TO SPREAD ACROSS THE REST OF
THE CWA LATE THIS AFTERNOON AND PERSIST THROUGH TUESDAY...PER
SATELLITE TRENDS AND NAM/GFS SFC-850 RH FCST. ALTHOUGH THE PCPN OVER
SRN WI CONTINUED TO SPREAD TO THE NORTH...WITH ONLY VERY WEAK FORCING
QVECTOR CONV...FGEN OR ISENTROPIC LIFT...ANY LIGHT SNOW MOVING INTO
THE AREA SHOULD BE VERY LIGHT AND BE CONFINED TO THE FAR SOUTH CWA
(SOUTH OF US-2)...PER GFS/ECMWF AND REGIONAL GEM. CLOUDS WILL HOLD
TEMPS UP TONIGHT WITH MIN READINGS MAINLY IN THE 20S. WITH THE
RELATIVELY MILD AIRMASS LINGERING OVER THE AREA TUESDAY...MAX
READINGS SHOULD STILL CLIMB INTO THE LOWER TO MID 30S...DESPITE THE
LINGERING CLOUDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 400 PM EST MON FEB 13 2012
WED THRU MON...UNDER SPLIT FLOW REGIME...ARCTIC AIR WILL BE BOTTLED
UP WELL TO THE N INTO NEXT WEEKEND...RESULTING IN TEMPS CONTINUING
TO AVERAGE ABOVE NORMAL. MODELS HINT AT A WEAK SHORTWAVE TO PASS
OVER THE UPPER GREAT LAKES WEDNESDAY. HOWEVER...MID AND UPPER LEVEL
DRY AIR ALONG WITH VERY LITTLE LIFT WILL KEEP MUCH OF UPPER MI
PREDOMINATELY DRY DURING THIS TIME FRAME.
CENTRALIZED SHORTWAVE TRAVERSING CALIFORNIA DURING THE DAY TODAY
WILL SLOWLY MOVE E TO THE CENTRAL PLAINS THROUGH WEDNESDAY...THEN
SHIFT TO A MORE NW DIRECTION...REACHING LAKE MI BY 12Z THURSDAY.
SOME MEDIUM RANGE MODELS ARE ALSO POINTING AT THE POTENTIAL FOR NRN
STREAM ENERGY TO PHASE WITH AND POSSIBLY STRENGTHEN THIS SRN STREAM
SYSTEM AS IT NEARS THE GREAT LAKES REGION. MODEL CONSENSUS KEEPS
MOST OF THE PRECIP CENTERED ALONG EASTERN EDGE OF THE PRESSURE
SYSTEM WHERE THE DEEPEST QVECTOR CONV/LIFT WILL BE LOCATED...AS WELL
AS ALONG THE ADJOINING COLD FRONT TO THE SOUTH. SOME OF THIS DEEP
MOISTURE AND QVECTOR CONV COULD REACH SC AND E UPPER MI DURING THE
DAY THURSDAY...ESPECIALLY AS SYSTEM BECOMES MORE WRAPPED UP. MODELS
HINT AT A TROWEL DEVELOPING...PULLING THE COLD FRONT ACROSS SOUTHERN
MENOMINEE COUNTY AND CENTRAL WI ALONG WITH 0.25 TO 0.5 INCH QPF
VALUES. THIS HAS BEEN CONSISTENT IN THE PREVIOUS TWO RUNS OF THE
GFS/ECMWF/AND NAM...THOUGH LATEST 13/12Z GFS AND GEM SEEMED TO PUSH
PRECIP FARTHER SOUTH. AS A RESULT...HAVE CONTINUED WITH EARLIER
CONSENSUS RUNS AND INCREASED POPS AND QPF ACROSS THE CWA. LATEST
MODEL RUNS ALSO SHOW COLDER 850 TEMPERATURE TRENDS...WHILE SURFACE
TEMPS WILL REMAIN RIGHT AT FREEZING...SO EXPECT SNOW TO BE THE MAIN
PRECIP TYPE. WILL CONTINUE TO MONITOR LATEST MODEL RUNS FOR ANY
CHANGE IN PLACEMENTS/WIND DIRECTIONS AND RESULTING PRECIP
TYPES/LOCATIONS.
MIDLEVEL DRY AIR AHEAD OF APPROACHING RIDGE WILL THEN CUT IN BY
THURSDAY NIGHT AS SHORTWAVE MOVES OFF TO THE NORTHEAST...REDUCING
PRECIP CHANCES FROM WEST TO EAST OVERNIGHT. THE RESULT OF THIS UPPER
LEVEL RIDGING WILL BE TO TURN WINDS MORE NORTHWESTERLY BY FRIDAY
INTO SATURDAY...ALLOWING ARCTIC AIR TO PENETRATE SOUTHWARD ACROSS
THE GREAT LAKES. 13/12Z GFS HAS H850 TEMPS DROPPING TO -17C
SATURDAY. THIS...ALONG WITH LINGERING LOW LEVEL MOISTURE...WILL
CREATE THE CONVERGENCE NEEDED FOR LAKE EFFECT SNOW FRIDAY THROUGH
SATURDAY IN AREAS ALONG LAKE SUPERIOR FAVORED BY NW WINDS. 13/12Z
ECMWF ALSO KEEPS WITH THIS TREND...THOUGH FALLING TEMPERATURES AND
AMOUNT OF CONVERGENCE ARE SLIGHTLY LESS MAGNIFIED. AS A
RESULT...HAVE INCREASED SLIGHT CHANCE TO CHANCE POPS ALONG LAKE
SUPERIOR IN AREAS FAVORED BY A NW WIND DIRECTION...KEEPING WITH
PREVIOUS FORECASTS.
ANY LINGERING LES EAST WILL COME TO AN END LATE SATURDAY...AS WINDS
BECOME MORE SOUTHWESTERLY...AHEAD OF THE NEXT SFC LOW/500MB TROUGH
APPROACHING FROM CENTRAL CANADA AND MN. THERE ARE SIGNIFICANT ENOUGH
TIMING DIFFERENCE TO RESULT IN MODERATE CONFIDENCE IN THE FCST
BEYOND THIS PERIOD. WHILE THE GFS AND ECMWF ARE IN FAIRLY GOOD SHAPE
UP UNTIL THIS POINT...THE 13/06Z RUN OF THE GFS BECOMES ROUGHLY 12
HRS SLOWER THAN THE MORE CONSISTENT ECMWF WITH THE HANDLING OF THIS
WAVE /CENTERED ACROSS THE UPPER GREAT LAKES AT 00Z MONDAY...WHILE
THE ECMWF HAS IT OVER THE LOWER GREAT LAKES/. WHILE THE ECMWF
INDICATES A DRY FRONTAL PASSAGE WITH THE SFC LOW CENTERED OVER
NORTHERN ONTARIO. GIVEN THE SLOWER AND MORE SOUTHERN GFS...A BROAD
SFC LOW WILL LIKELY DEVELOP OVER THE GREAT LAKES...WITH LIGHT PRECIP
AND PLENTY OF CLOUD COVER BEFORE THE SYSTEM EJECTS EASTWARD MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 546 PM EST MON FEB 13 2012
A DISTURBANCE MOVING FROM THE CNTRL PLAINS TO THE LOWER GREAT LKS
WILL HAVE THE LOWER TO MID CLOUDS TO LOWER THROUGH THE NIGHT AND
LIKELY BE IN THE MVFR CAT AFTER 06Z.
MODELS WERE HINTING AT PLENTY OF LLVL MOISTENING...WHICH COULD LEAD
TO SOME REDUCED VSBYS FROM BR. WITH LIMITED LLVL LIFT AND SINCE
WINDS WILL BE OUT OF AN UNFAVORABLE SWRLY DIRECTION...WILL KEEP VSBY
REDUCTION OUT AT THIS TIME.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON FEB 13 2012
A HIGH PRESSURE RIDGE BUILDING OVER THE AREA WILL KEEP WINDS BELOW
20KTS TONIGHT THROUGH WEDNESDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS ON WED NIGHT WILL MOVE THROUGH
THE GREAT LAKES REGION FROM THURSDAY INTO FRIDAY. THIS WILL
LEAD TO NW WINDS UP TO 25KTS OVER ERN LK SUPERIOR. HIGH PRESSURE
WILL THEN MOVE OVER THE AREA FOR THE FIRST PART OF THE WEEKEND AND
KEEP WINDS BELOW 20KTS. WITH ABOVE NORMAL TEMPERATURES THROUGH THE
PERIOD...LITTLE TO NO FREEZING SPRAY IS EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...JMW
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1123 PM CST MON FEB 13 2012
.UPDATE...
ISSUED AT 910 PM CST MON FEB 13 2012
REVIEW OF 00Z NAM AND RUC DATA AS WELL AS OBSERVED DATA SHOWS
DRIZZLE THREAT TO BE WITH US FOR A WHILE WITH MUCH OF THE MID AND
HI LEVEL CLOUDS NOW STRIPPED AWAY LEAVING BEHIND EXPANSIVE LO
CLOUD DECK. STILL NEED WEAK LIFT...WHICH WILL BE PROVIDED BY
EITHER WEAK CYCLONIC FLOW OR TROF THAT WILL MOVE THRU LATE TONIGHT
AND EARLY TUESDAY MORNING. TEMPS CURRENTLY AT OR BELOW FREEZING AT
ALL LOCATIONS...AND DESPITE S SFC WNDS...ADVECTION THAT RESULTS IS
NEUTRAL...SO WE SHOULD SEE NEAR STEADY TEMPS OVERNIGHT...TO KEEP
THE DRIZZLE FREEZING ON EXPOSED AND/OR UNTREATED SURFACES.
EXTENDED THE WSW WHICH WAS ALREADY IN EFFECT UNTIL MIDNIGHT...
UNTIL 6AM. MAY NEED TO BE EXTENDED FURTHER BEYOND 12Z TUESDAY FOR
PARTS OF THE ERN FA IF TROF IS SLOWER THAN ANTICIPATED.
TES
&&
.SHORT TERM...
ISSUED AT 300 PM CST MON FEB 13 2012
(TONIGHT)
FOCUS TONIGHT WILL BE THE ONGOING PRECIP ACROSS THE REGION.
UPPER TROF CURRENTLY OVER NEB/KS REGION WILL MOVE THRU THE CWA
TONIGHT BRINGING THE SN TO AN END. AS OF 19Z...FIRST BAND OF HEAVY
PRECIP IS MOVING OUT OF CNTL MO AND INTO THE ERN PORTIONS OF MO AND
IL. THIS IS EXPECTED TO BE THE BULK OF THE SN FOR THE NWRN THIRD OF
THE CWA. MDLS STILL INDICATE ANOTHER S/W LIFTING NEWD LATE THIS
AFTERNOON AND EARLY EVE RESULTING IN ANOTHER BAND OF HEAVIER SN FOR
AREAS ROUGHLY ALONG AND E OF A LINE FROM VIH/STL/3LF.
ONCE THE SN COMES TO AN END...STILL EXPECT PATCHY FZDZ TO LINGER FOR
A COUPLE OF HRS AS THE DEEP CLOUD LAYER IS LOST. A LOT OF
UNCERTAINTY REGARDING HOW LONG THE FZDZ WILL CONTINUE OVERNIGHT.
HAVE KEPT MENTION OF FZDZ OVERNIGHT FOR NOW WITH UPDATES AS NEEDED.
AS FOR TEMPS OVERNIGHT...HAVE A QUICK DROP IN TEMPS SHORTLY AFTER
SUNSET. HOWEVER...EXPECT TEMPS TO REMAIN NEARLY STEADY OVERNIGHT
GIVEN SLY FLOW AND AMPLE CLOUD COVER.
TILLY
&&
.LONG TERM...
ISSUED AT 300 PM CST MON FEB 13 2012
(TUESDAY THROUGH MONDAY)
IN THE WAKE OF TONIGHTS STORM SYSTEM...HEIGHTS WILL RISE ALOFT ON
TUESDAY AND LOW LEVEL WAA WILL GET UNDERWAY IN ERNEST AS THE LOW
LEVEL RIDGE PASSES TO THE EAST. NORMALLY THIS WOULD ALLOW FOR A
SIGNIFICANT WARM-UP AS H85 TEMPS RISE ON THE ORDER OF +6 TO +8
DEGC. HOWEVER SIGNIFICANT LOW CLOUDS ARE EXPECTED TO BLANKET THE
AREA AT THE START OF THE DAY AND THESE WILL GRADUALLY CLEAR WEST
TO EAST. THIS TREND COMBINED WITH LIGHT SNOW COVER SHOULD KEEP
TEMPS IN CHECK AND HAVE FAVORED HIGHS CLOSER TO THE COOLER MET GUIDANCE.
THE NEXT BIG SYSTEM TO IMPACT THE AREA IS ON TRACK FOR WED/WED
NIGHT AND IS CURRENTLY CENTERED IN CALIFORNIA. THE GUIDANCE IS IN
GOOD AGREEMENT THAT THE UPPER TROF MOVING THROUGH THE GULF OF AK
WILL BE THE KICKER AS IT DIGS SSEWD ALONG THE WEST COAST OVER THE
NEXT 48H...EJECTING THE CALIFORNIA TROF THROUGH THE SOUTHERN
ROCKIES AND INTO THE PLAINS ON WEDNESDAY AND THROUGH THE MID MS
VALLEY ON WED NIGHT. THIS UPPER SYSTEM SHOULD WEAKEN AS IT MOVES
THROUGH OUR AREA AS IT ENCOUNTERS INCREASINGLY CONFLUENT FLOW
ALOFT.
AFTER LOSING THE LOW CLOUDS ON TUESDAY...MID/HI CLOUDS WILL BEGIN
TO SPREAD BACK INTO THE AREA ON TUESDAY NIGHT IN ADVANCE OF THE
MIGRATING UPPER TROF. PRECIPITATION SHOULD BEGIN TO EVOLVE LATE
TUESDAY NIGHT ACROSS THE PLAINS IN RESPONSE TO STRENGTHENING LOW
LEVEL WAA AND MOISTURE TRANSPORT. AT THIS TIME I AM THINKING IT
WILL HOLD OFF IN OUR CWA UNTIL AFTER 14-15Z...AT LEAST HOPING SO.
IF IT STARTS EARLIER THERE COULD BE SOME AREAS WITH SUB-FREEZING
SURFACE TEMPERATURES TO CONTEND WITH.
BY AFTERNOON ON WEDNESDAY...THE COVERAGE OF RAIN SHOULD INCREASE
DRAMATICALLY IN RESPONSE TO STRONG LOW LEVEL WAA AND CONTINUE
MOISTURE TRANSPORT INTO THE AREA VIA A SSWLY LLJ...AND INCREASING
LARGE SCALE ASCENT ASSOCIATED WITH THE UPPER TROF. SOUNDINGS AND
MODEL DELTA THETAE PROGS SHOW THE DEVELOPMENT OF ELEVATED INSTABILITY
AS MID LEVEL LAPSE RATES AOA 7 DEGC/KM SPREAD INTO THE AREA IN
ADVANCE OF THE TROF AND OVERSPREAD THE WARMING/MOISTENING LOW
LEVELS. THEREFORE I HAVE ADDED A CHANCE OF THUNDER FROM THE
AFTERNOON INTO THE EVENING HOURS. THE RAIN SHOULD TAPER AFTER
MIDNIGHT AS THE WARM CONVEYOR BELT MOVES EASTWARD IN ASSOCIATION
WITH THE ADVANCING UPPER TROF. THE SPEED OF THIS SYSTEM VARIES IN
SOME IN THE GUIDANCE...BUT ALL SUGGEST THE PRECIPITATION WILL BE
OVER BY THE TIME ANY DEEPER COLD AIR ARRIVES IN ITS WAKE THAT
WOULD SUPPORT SNOWFALL.
THE WHOLE UPPER PATTERN IS SOMEWHAT PROGRESSIVE THURSDAY AND
BEYOND. THE MODELS SHOW A SPLIT REGIME ON FRIDAY WITH A SOUTHERN
STREAM UPPER LOW IN WEST TX AND DEEPER NORTHERN STREAM TROF FROM
HUDSON BAY INTO THE GREAT LAKES. AFTER FRIDAY THE DETERMINISTIC
MODELS AND ENSEMBLES/MEMBERS QUICKLY DIVERGE AND SHOW MUCH SPREAD
SATURDAY THROUGH MONDAY. THIS LEADS LOW CONFIDENCE IN DETAILS...HOWEVER
THE GENERAL TRENDS SHOW NO SIGNFICANT WEATHER SYSTEMS IN THIS TIME
FRAME AND TEMPERATURES AT OR ABOVE AVERAGE.
GLASS
&&
.AVIATION...
ISSUED AT 1113 PM CST MON FEB 13 2012
IFR FLIGHT CONDITIONS IN OCCASIONAL LIGHT FREEZING
DRIZZLE...FOG...AND LOW STRATUS WILL PREVAIL FOR THE REST OF THE
NIGHT. ADDITIONALLY...THE UPPER LEVEL ENERGY ASSOCIATED WITH THIS
STORM SYSTEM WILL RIPPLE ACROSS THE AREA THROUGH 12Z PRODUCING A
BRIEF BURST OF SNOW WHICH WILL REDUCE THE VISIBILITY TO AROUND 1SM
AS IT PASSES. CONDITIONS WILL IMPROVE GRADUALLY AFTER
SUNRISE...THOUGH IT WILL TAKE MOST OF THE MORNING BEFORE CIGS RISE
ABOVE 900FT AGL. SLOW IMPROVEMENT WILL CONTINUE IN THE
AFTERNOON...AND EVENTUALLY CLOUDS SHOULD CLEAR OUT BEFORE SUNSET.
SPECIFICS FOR KSTL...
IFR FLIGHT CONDITIONS WILL CONTINUE TO PREVAIL AT LAMBERT AT LEAST
THROUGH MID MORNING. WILL CONTINUE TO SEE OCCASIONAL LIGHT
FREEZING DRIZZLE AT THE TERMINAL UNTIL AROUND 12Z...AND THERE WILL
BE A BRIEF BURST OF SNOW BETWEEN 07Z-09Z WHICH WILL BRING THE
VISIBILITY DOWN TO AROUND 1SM AS THE UPPER LEVEL ENERGY ASSOCIATED
WITH THIS STORM RIPPLES BY. SHOULD SEE SLOW IMPROVEMENT AFTER
SUNRISE WITH CIGS RISING ABOVE 900FT AGL BY NOON AND SCATTERING
BEFORE 00Z.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN
MO-MADISON MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-REYNOLDS MO-SHELBY MO-ST. CHARLES
MO-ST. FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS MO-STE.
GENEVIEVE MO-WARREN MO-WASHINGTON MO.
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR ADAMS IL-BOND
IL-BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-
JERSEY IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-
MONTGOMERY IL-PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
900 PM MST WED FEB 15 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
UPDATED THE FORECAST TO LOWER THE OVERNIGHT LOWS DOWN ACROSS MOST
OF THE CWA. LOWS ARE ALREADY DROPPING IN TO THE LOWER 20S AND
UPPER TEENS. WITH THE NEW SNOW PACK AND CLEAR SKIES FORECAST FOR
TONIGHT FEEL LIKE THE OVERNIGHT LOWS WERE A LITTLE TO WARM. MODELS
DATA WASN`T MUCH HELP EITHER SINCE THE OBSERVED DATA WAS ALREADY
COLDER THEN WHAT THE MODELS WERE SHOWING FOR OVERNIGHT LOWS.
DECIDED TO USE TH HRRR MODEL OUTPUT AND THEN ADJUST DOWN TO THE
NEAR OBSERVED EVENING DEW POINTS. RSMITH
PREVIOUS DISCUSSION...WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD
SHOWS A SOMEWHAT HALTED AND STAGNANT SPLIT UPPER LEVEL FLOW
REGIME. THE SOUTHERN STREAM CONTINUES TO SHOWCASE A SERIES OF
CLOSED UPPER LOW CENTERS MOVING SOUTHWARD OVER THE CASCADES THEN
TURNING SHARPLY EASTWARD THROUGH THE FOUR CORNERS AREA...SPAWNING
THUNDERSTORMS NEAR THE SOUTHERN MISSISSIPPI RIVER VALLEY. THE
NORTHERN STREAM IS CHARACTERIZED MAINLY BY ALTERNATING SHORT WAVE
UPPER LEVEL TROUGHS AND RIDGES. THE NORTHERN STREAM IS CURRENTLY
INFLUENCING NORTHEAST MONTANA MORE THAN THE SOUTHERN STREAM WITH
NORTHWESTERLY FLOW ALOFT.
SATELLITE IMAGERY WITH CLEARING SKIES TODAY REVEALS THE NEW SNOW
FIELD FROM YESTERDAYS STORM. THE MAJORITY OF THE HEAVY SNOW PACK
SEEMS TO BE LOCATED IN PHILLIPS AND VALLEY COUNTIES. TEMPERATURES
THERE ARE TOPPING OUT NEAR OR JUST BELOW THE THAWING OR FREEZING
MARK. TEMPERATURES FURTHER SOUTH OVER BARE GROUND ARE NEARING 40
DEGREES THIS AFTERNOON.
FORECAST CHALLENGES WILL FOCUS MAINLY ON TEMPERATURES AND SLIGHT
CHANCES FOR SNOW THURSDAY NIGHT THROUGH FRIDAY MORNING. TONIGHT
THROUGH THURSDAY AFTERNOON...NORTHEAST MONTANA FINDS ITSELF
SQUARELY IN BETWEEN RIDGING FROM THE SOUTHWEST AND TROUGHING FROM
THE NORTH AND NORTHEAST. NORTHWEST FLOW ALOFT WILL DOMINATE AND A
RELATIVELY DRY ENVIRONMENT WILL PREVENT ANY SUBSTANTIAL
PRECIPITATION THROUGH THIS MIDDLE PORTION OF THE WEEK.
THURSDAY NIGHT THROUGH FRIDAY MORNING...AN UPPER LEVEL TROUGH
FROM SASKATCHEWAN PROVIDES SOME WEAK LIFT WHICH MAY COOPERATE JUST
ENOUGH WITH THE EXPECTED PACIFIC MOISTURE TO BRING SOME LIGHT SNOW
OVER OUR SOUTHWESTERN ZONES. DO NOT EXPECT MUCH FROM IT. FRIDAY
UPPER LEVEL RIDGING RETURNS AND CUTS OFF THE MOISTURE. THE
TEMPERATURE FORECAST IN THE SHORT TERM WILL BECOME HIGHLY
DEPENDENT ON THE SLOWLY ERODING NEW SNOW PACK OVER CENTRAL AND
NORTHWESTERN PORTIONS OF OUR CWA. COLDER MAX TEMPS OVER THE SNOW
CAN BE EXPECTED OVER THE NEXT FEW DAYS AS THE SNOW PACK MELTS TO
BARE GROUND FROM THE SOUTH. BMICKELSON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
MODELS ARE SHOWING A WEAKENING TREND WITH A DISTURBANCE MOVING
THROUGH THE AREA LATE SUNDAY INTO EARLY NEXT WEEK...SO LOWERED
POPS ACCORDINGLY. OTHERWISE... TEMPS WERE LOWERED A BIT FRIDAY
NIGHT MAINLY ACROSS THE NORTHERN ZONES WITH THE FRESH SNOWCOVER
PRESENTLY IN PLACE. REST OF FORECAST LOOKS GOOD. JAMBA
PREVIOUS DISCUSSION...
LONG TERM FORECAST PERIOD BEGINS WITH AN UPPER LEVEL RIDGE OVER
ALL OF CENTRAL MONTANA. FRIDAY NIGHT INTO SATURDAY AFTERNOON AN
APPROACHING UPPER LEVEL LOW MOVES ONSHORE OVER THE PACIFIC
NORTHWEST PUSHING THE UPPER RIDGE EASTWARD INTO THE NORTHERN
PLAINS. THIS UPPER LOW BECOMES MORE OF AN OPEN WAVE WHICH WILL
SPLIT AND SEND THE MORE ACTIVE PART OF THE SYSTEM OVER THE CENTRAL
ROCKIES. THE NORTHERN PART OF THIS OPEN WAVE WILL CROSS THE
NORTHERN ROCKIES AND IT WILL TRIGGER SOME LIGHT SNOW SHOWERS
ACROSS NEMONT SATURDAY NIGHT THROUGH SUNDAY NIGHT. LOOKS LIKE
ANOTHER INCH OR TWO OF SNOW WILL BE POSSIBLE BUT KEPT POPS IN THE
LOWER CHANCE RANGE FOR NOW.
MODELS TAKE THE SOUTHERN PART OF THIS UPPER WAVE INTO THE CENTRAL
PLAINS BY MONDAY AND IT BECOMES VERTICALLY STACKED. IT LOOKS AS
THOUGH THIS SYSTEM WILL BE TOO FAR TO THE SOUTH TO EFFECT WEATHER
ACROSS EASTERN MONTANA.
GENERALLY THE UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE
REST OF THE EXTENDED AND NORTHEAST MONTANA SEEMS PINNED BETWEEN A
RIDGING INFLUENCE FROM THE SOUTHWEST AND CONTINUED TROUGHING OVER
THE GREAT LAKES. THIS MEANS EASTERN MONTANA WILL BE IN THE NORTHWEST
FLOW WITH DISTURBANCES MOVING THROUGH THIS FLOW FROM MONDAY
THROUGH THURSDAY NIGHT. MODELS ARE ALL DIFFERENT ON TIMING OF
THESE WAVES BUT TUESDAY NIGHT INTO WEDNESDAY LOOKS LIKE A PERIOD
THAT THE MODELS ARE IN SOME AGREEMENT FOR MORE LIGHT SNOWFALL. SO
ADDED SOME SLIGHT CHANCE POPS TO THIS TIME FRAME. RSMITH
&&
.AVIATION...
VFR. MAINLY CLEAR SKIES ARE EXPECTED TONIGHT BUT LOW VFR CLOUDS
WILL DRIFT SOUTHEAST ACROSS THE AREA INTO THURSDAY AS AN UPPER
DISTURBANCE SPINS UP OVER SOUTHERN SASKATCHEWAN. WINDS WILL BE
LIGHT FROM THE NORTHWEST. JAMBA/PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
341 PM MST TUE FEB 14 2012
.SHORT TERM...VALID FOR WED AND THU...
A SHORT WAVE TROUGH CONTINUES MOVING EAST-SOUTHEAST ACROSS MT THIS
AFTERNOON...AND RUC OBJECTIVE ANALYSES SUGGEST THE 1.5 PVU SURFACE
ASSOCIATED WITH THIS FEATURE HAS LOWERED TO 500 HPA. PRECIPITATION
ASSOCIATED WITH THIS WAVE WILL BE THE MAIN FORECAST ISSUE OVER THE
NEXT 6 TO 12 HOURS...BUT THEN OUR CHALLENGE WILL MAINLY TRANSITION
TO ONE OF TEMPERATURES. WE SET THE 12 UTC NAM SOLUTION ASIDE WHILE
DEVELOPING THE SHORT TERM FORECAST SINCE IT IS AN OUTLIER COMPARED
TO THE REST OF THE GUIDANCE IN HOW IT HANDLES SOME KEY FEATURES IN
SPLIT FLOW OVER THE CONUS AND A NORTHWEST 500-HPA PATTERN OVER MT.
WE WILL MAINTAIN SOME 40 TO 60 PERCENT POPS ACROSS SOUTHEASTERN MT
AND SHERIDAN COUNTY WY THROUGH THE EVENING GIVEN FAIRLY WIDESPREAD
SNOW SHOWER ACTIVITY AHEAD OF THE 500-HPA SHORT WAVE. RADAR IMAGES
SUGGEST THIS PRECIPITATION IS LIKELY BEING ENHANCED A BIT IN AREAS
LIKE SOUTHERN BIG HORN COUNTY WHERE LOW-LEVEL UPSLOPE FLOW EXISTS.
IN GENERAL THOUGH...WE WILL SIMPLY TIME THE FORCING CONCOMITANT TO
THE WAVE EAST...WITH ONLY A LOW CHANCE OF SNOW SHOWERS IN ITS WAKE
FOR THE EVENING WHERE LOW-LEVEL INSTABILITY LINGERS IN PLACES LIKE
BILLINGS. THE MULTI-MODEL CONSENSUS SUGGESTS WE WILL MAINLY HAVE A
DRY FORECAST IN PLACE AFTER 06 UTC...WITH ONLY SOME LOW POPS STILL
NEEDED OVER FAR SOUTHEASTERN MT AND IN THE MOUNTAINS. WE WILL ALSO
HAVE LOW POPS OVER THE MOUNTAINS ON WED AND THU WITH THE NORTHWEST
FLOW ALOFT.
ON WED...FORECAST SOUNDINGS SUGGEST MIXING UP TO 800 HPA OVER MOST
OF THE PLAINS...WHICH YIELDS HIGHS CLOSE TO 40 F. WE USED THE MIX-
DOWN NUMBERS BASED ON GFS THERMAL PROFILES TO DERIVE OUR HIGHS. IN
THIS PATTERN WITH LOW-LEVEL WEST-NORTHWEST DOWNSLOPE FLOW AND LACK
OF SNOW COVER ON THE PLAINS...MOS-BASED NUMBERS WILL LIKELY END UP
BEING TOO COLD. CYCLONIC FLOW LINGERS ALOFT AND FORECAST SOUNDINGS
SHOW SOME MID-LEVEL SATURATION AS CONVECTIVE THERMALS GET GOING IN
THE 18 TO 00 UTC TIME FRAME...SO SOME DIURNALLY-DRIVEN SHOWERS MAY
OCCUR...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE THE CHANCE IN
THE FORECAST AT THIS POINT.
FOR THU...WARMER MID-LEVEL TEMPERATURES LOOK TO BE IN PLACE...WITH
DOWNSLOPE LOW-LEVEL FLOW PERHAPS ACCENTUATED THANKS TO THE PASSAGE
OF A WEAK WAVE TO OUR NORTH. WE CAUTIOUSLY MIXED DOWN TEMPERATURES
FROM 850 OR 800 HPA USING 12 UTC GFS AND ECMWF GUIDANCE /WHICH ARE
SHOWING 850-HPA TEMPERATURES OF +1 TO +3 C/ TO CALL FOR HIGHS WELL
INTO THE 40S F. THIS DOES PUT OUR FORECAST ON THE WARM SIDE OF THE
GUIDANCE ENVELOPE...BUT THIS IS WHERE WE WANT TO BE IN A SITUATION
LIKE THIS...WHICH REALISTICALLY COULD HAVE SOME 50 F READINGS WITH
EFFICIENT MIXING. SCHULTZ
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
DIRTY NORTHWEST FLOW ON FRIDAY WILL TRANSITION TO WESTERLY FLOW
SATURDAY AHEAD OF WHAT IS BECOMING A STRONGER SYSTEM FOR SATURDAY
NIGHT INTO SUNDAY. KEPT MENTION OF SLIGHT CHANCE POPS ON FRIDAY
WITH NORTHWEST FLOW OVER THE AREA. SATURDAY LOOKS MAINLY DRY WITH
DOWNSLOPE WINDS BOOSTING TEMPERATURES POSSIBLY INTO THE LOWER 50S
SATURDAY AFTERNOON. COLD FRONT AND PRECIPITATION SHOULD MOVE INTO
THE AREA FROM THE WEST SATURDAY EVENING...WITH TROF OVERHEAD INTO
MONDAY. BEST CHANCES FOR PRECIPITATION WILL BE SATURDAY NIGHT INTO
SUNDAY...WITH LOW POPS LINGERING INTO MONDAY UNDERNEATH THE TROF.
TEMPERATURES SUNDAY AND MONDAY LOOK TO REMAIN MAINLY IN THE 30S.
HEIGHT RISES ADVECT IN FROM THE WEST ON TUESDAY FOR WARMER
DOWNSLOPE PATTERN. MODELS ARE IN PRETTY GOOD AGREEMENT WITH MOST
PARAMETERS THROUGH SATURDAY NIGHT...HOWEVER THE LATEST ECMWF MOVES
THE SYSTEM OUT OF THE AREA FASTER RESULTING IN DRIER CONDITIONS
SUNDAY NIGHT AND MONDAY. CURRENTLY TRENDING A BIT TOWARD THE GFS
FOR CONTINUITY. CHAMBERS
&&
.AVIATION...
RAIN AND SNOW SHOWERS WILL CONTINUE THIS EVENING MAINLY EAST OF
BILLINGS. PERIODS OF HEAVIER SNOW SHOWERS IN THE KSHR AND KMLS
AREAS MAY TEMPORARILY LIMIT FLIGHT CONDITIONS TO
IFR/LIFR/VLIFR...WITH IFR CONDITIONS PREVAILING. GUSTY WINDS ARE
EXPECTED ACROSS MUCH OF THE AREA THROUGH EARLY THIS
EVENING...MAINLY FROM KBIL WEST. MOUNTAIN OBSCURATIONS ARE
EXPECTED THROUGH THIS EVENING...MAINLY IN THE BIG HORN AND
BEARTOOTH MOUNTAINS. OTHERWISE...CONDITIONS WILL CONTINUE TO
IMPROVE FROM WEST TO EAST OVERNIGHT. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 017/041 022/046 030/043 024/047 025/036 020/036 020/042
21/B 00/B 12/W 11/B 53/J 12/J 21/B
LVM 013/035 018/042 023/042 021/046 022/030 015/031 017/039
11/B 00/N 12/J 12/W 53/J 22/J 21/B
HDN 021/041 020/048 029/044 022/048 022/037 017/037 017/042
31/B 00/B 12/W 11/B 43/J 12/J 21/B
MLS 018/040 021/046 026/041 022/046 024/038 020/037 018/041
41/B 00/B 11/B 11/B 23/J 12/J 21/B
4BQ 019/038 020/044 026/040 022/045 024/035 017/035 016/039
50/B 00/B 12/J 11/U 24/J 32/J 22/J
BHK 017/037 019/043 023/038 020/042 024/036 017/035 015/037
51/B 00/B 01/B 11/U 13/J 22/J 21/B
SHR 013/037 017/043 024/040 019/044 020/031 013/034 013/038
61/B 11/B 12/J 21/U 34/J 22/J 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
933 AM MST TUE FEB 14 2012
.SHORT TERM...VALID FOR TDY AND WED...
A VIGOROUS SHORT WAVE TROUGH WITH ITS AXIS FROM GREAT FALLS TOWARD
BOZEMAN AS OF 16 UTC WILL SWEEP EAST-SOUTHEAST ACROSS MT TODAY. IT
LOOKS LIKE QUITE A BIT IN THE WAY OF DYNAMICS WILL BE ACCOMPANYING
THIS FEATURE...WITH THE 1.5 PVU SURFACE LOWERING TO AROUND 520 HPA
BY 00 UTC. HOWEVER...Q-VECTOR CONVERGENCE IS NOT VERY POTENT...AND
THE FAST MOVEMENT OF THE WAVE IS NOT ESPECIALLY FAVORABLE FOR LOTS
OF MOISTURE. NONETHELESS...GIVEN STEEP MID-LEVEL LAPSE RATES ALONG
WITH UPSTREAM TRENDS...WE DID INCREASE POPS INTO THE 40-50 PERCENT
RANGE FROM ROUNDUP SOUTHEAST TO MILES CITY AND BAKER DURING THE 18
TO 00 UTC TIME FRAME...AND LINGERING PAST 00 UTC AROUND BAKER. THE
GFS ENSEMBLE MEMBERS FROM 00 UTC STILL MAKE A GOOD CASE FOR QPF IN
SOUTHEASTERN MT THIS AFTERNOON AND EVENING TOO. SNOW IS ALSO GOING
AS OF 16 UTC IN THE FOOTHILLS AND AROUND JUDITH GAP...SO POPS OVER
THOSE AREAS WILL REMAIN IN THE 70 TO 90 PERCENT RANGE TODAY. THERE
IS STILL LITTLE SUGGESTION IN GUIDANCE OR TRENDS FOR ANYTHING MORE
THAN ABOUT AN INCH OR TWO OF SNOW IN THE LOWER ELEVATIONS WITH THE
WAVE...BUT WE WILL CONTINUE TO MONITOR FOR THAT POSSIBILITY.
ONLY MINOR CHANGES WERE MADE TO THE REST OF THE FORECAST WITH THIS
UPDATE...MAINLY TO INCREASE HIGHS EVER-SO-SLIGHTLY IN PLACES GIVEN
THE WARM START...AND TO SOMEWHAT AMBITIOUSLY ADVERTISE A PERIOD OF
20 TO 30 MPH WINDS DURING THE AFTERNOON OVER SOUTH CENTRAL MT. THE
WINDS ARE PREDICATED ON THE POSSIBILITY OF SUBSIDENCE HELPING PUSH
WINDS TO THE SURFACE IN THE WAKE OF THE STOUT 1.5 PVU LOWERING. WE
ALSO NOTED THAT RUC SOUNDINGS AT BILLINGS HAVE 35 KT WINDS AT THE
TOP OF THE MIXED LAYER FROM 21 TO 00 UTC. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MADE BROADER CHANGES TO THE LATER PERIODS OF THE EXTENDED FORECAST
AS MODELS ARE HINTING AT BETTER CHANCES FOR TROUGHINESS TO
INFLUENCE THE WEATHER FOR SUNDAY AND BEYOND. THURSDAY LOOKS A BIT
DOWNSLOPISH WHICH SHOULD KEEP THE PLAINS DRY AS MOISTURE CONTINUES
TO TRIGGER OROGRAPHIC SHOWERS IN THE MOUNTAINS. NOT A REAL STRONG
DOWNSLOPE SO NOT EXPECTING MUCH OF A WARMUP.
FRIDAY AN UPPER LEVEL RIDGE BUILDS INTO THE PACIFIC NORTHWEST
BRINGING A BIT OF WARM AIR ADVECTION ALOFT. THIS WILL BE LINING UP
WITH A SHOT OF COOLER AIR WHICH SLIDES INTO THE EASTERN END OF THE
STATE. IF THE COLD AIR PUSHES FAR ENOUGH WEST AN OVERRUNNING
PATTERN COULD BE SETUP ESPECIALLY IF SOME UPSLOPE CAN BE
ESTABLISHED ALONG THE FOOTHILLS. PATTERN DOES LOOK WEAK BUT WILL
HAVE TO WATCH FOR THIS LINING UP A BIT BETTER IF THE UPPER FLOW
PATTERN CAN BE MORE AMPLIFIED THAN CURRENTLY PROGGED. RIDGE
CROSSES THE AREA ON SATURDAY WHICH SHOULD BRING A DRY AND STABLE
PERIOD. THIS SHOULD BRING THE BEST CHANCE OF HAVING TEMPERATURES
REACH THE MID 40S.
NEXT SYSTEM MOVES INTO THE REGION BEHIND THE RIDGE AND TAKES ITS
TIME MOVING THROUGH MONTANA AND WYOMING. EXACT DETAILS MAKE IT
DIFFICULT TO SEE WHEN THE BEST CHANCE FOR PRECIPITATION WILL BE
DURING THE SUNDAY THROUGH TUESDAY TIME FRAME BUT IT DOES LOOK LIKE
UNSETTLED AND COOLER SHOULD REIGN. HAVE GONE WITH BETTER CHANCES
FOR PRECIPITATION IN THE LOWER ELEVATIONS DURING THIS PERIOD AND
COOLED TEMPERATURES A BIT. ECMWF DOES TAKE THE UPPER LOW NORTH OF
THE AREA WHICH WOULD BE A DRIER PATTERN SO NOTHING MORE THAN
ISOLATED POPS HAVE BEEN ADDED. BORSUM
&&
.AVIATION...
DISTURBANCE MOVING ACROSS THE AREA TODAY WILL BRING RAIN AND SNOW
SHOWERS. THIS WILL BRING A CHANCE OF MVFR CONDITIONS WITH THE
STRONGER SHOWERS THIS AFTERNOON FOR KBIL...KMLS AND KSHR. GUSTY
WINDS ARE EXPECTED TO DEVELOP ACROSS THE PLAINS FROM KLVM TO KBIL
THIS AFTERNOON...BEFORE DIMINISHING THIS EVENING. EXPECT DECREASING
CLOUDS FROM WEST TO EAST TONIGHT. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 040 017/038 022/040 025/041 024/045 022/038 021/038
3/J 21/B 00/B 12/W 11/B 02/J 22/J
LVM 036 014/035 018/039 021/038 022/042 022/035 019/035
5/J 21/B 00/B 12/W 11/B 12/J 12/J
HDN 040 021/039 020/040 020/041 021/045 020/040 018/040
4/W 21/B 00/B 12/W 11/B 01/B 22/J
MLS 037 017/037 021/039 021/039 021/043 021/038 020/038
5/J 31/B 01/B 11/B 11/B 11/B 22/J
4BQ 039 019/035 020/037 020/040 020/044 020/039 019/039
4/J 32/J 00/B 12/W 11/U 01/B 22/J
BHK 035 016/036 019/037 017/038 018/040 018/037 016/035
4/J 41/B 00/B 01/B 11/U 01/B 12/J
SHR 039 016/036 017/038 018/040 018/043 019/038 016/038
5/J 61/B 11/B 12/W 21/U 12/J 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
828 PM EST WED FEB 15 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA WILL BRING SOME CLEARING TO
THE AREA FOR AWHILE THIS EVENING AND EARLY TONIGHT. CLOUDS WILL
RETURN DURING THE SECOND HALF OF THE NIGHT AS RAIN SPREADS NORTH OF
AN AREA OF LOW PRESSURE THAT WILL BE MOVING OUT OF THE SOUTHERN
PLAINS STATES. THE RAIN WILL SPREAD EAST ACROSS OUR AREA
THURSDAY...THEN TAPER OFF THURSDAY NIGHT WHILE A CHANGEOVER TO SNOW
TAKES PLACE. THE RAIN WILL BE ALSO ACCOMPANIED BY UNSEASONABLY MILD
TEMPERATURES ON THURSDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
THROUGH 830 PM...SATELLITE SHOWS SKIES HAVE CLEARED ACROSS
PORTIONS OF WESTERN NEW YORK...AS LOW CLOUDS HAVE DISSIPATED WEST
OF ROCHESTER AND SYRACUSE. THIS WILL BE SHORT LIVED...AS MID AND
HIGH CLOUDS APPROACH FROM THE SOUTHWEST...BUT THIS SHOULD ALLOW
TEMPERATURES TO DROP THROUGH THIS EVENING. BECAUSE OF THIS...DID
LOWER FORECAST LOWS IN AREAS EXPECTED TO CLEAR.
MEANWHILE...THE 18Z GFS AND LATEST RUNS OF THE HRRR HAVE JOINED
THE EARLIER TIMING OF THE 12Z RGEM. WHILE THE SE FLOW WILL LIKELY
DELAY THE START TIME A BIT DUE TO DOWNSLOPING LIKE THE NAM/SREF
ARE HINTING...DID MOVE UP THE START BY A COUPLE HOURS TO ACCOUNT
FOR THE NEW RUNS WHICH ARE FASTER.
THIS WILL HAVE MODEST IMPLICATIONS ON PRECIPITATION TYPE...AS THE
STARTING TEMPERATURES WILL BE A TAD COLDER DUE TO THIS CLEARING
AND THE SLIGHTLY EARLIER START TIME. FORECAST SOUNDINGS SUGGEST
TEMPERATURES ALOFT WILL ONLY WARM TO NEAR OR JUST ABOVE FREEZING
AT 12Z THURSDAY. ALONG THE LAKE SHORE...EXPECT DOWNSLOPING TO
HELP WARM SURFACE TEMPERATURES ENOUGH FOR ALL RAIN.
HOWEVER...ACROSS HIGHER TERRAIN OF THE SOUTHERN TIER...PRECIPITATION
MAY START OFF MIXED WITH SLEET OR SNOW BEFORE CHANGING OVER TO ALL
RAIN BY MID MORNING. LITTLE IN THE WAY OF ACCUMULATION IS
EXPECTED. WILL ALSO CONTINUE TO WATCH FOR A BRIEF PERIOD OF
FREEZING RAIN AT THE ONSET.
SURFACE TEMPERATURES ARE LIKELY TO REMAIN BELOW FREEZING A LITTLE
LONGER EAST OF LAKE ONTARIO...BUT THE RAIN IS NOT EXPECTED TO
REACH THIS AREA UNTIL AFTER TEMPERATURES HAVE WARMED ABOVE
FREEZING. THE THERMAL PROFILES MAY STAY COLD ENOUGH FOR A MIX OF
RAIN AND SNOW ACROSS THE HIGHER ELEVATIONS OF LEWIS COUNTY.
LOW PRESSURE NEAR OKLAHOMA IS FORECAST TO TRACK TO THE NORTHEAST
OVERNIGHT AND REACH NORTHERN INDIANA BY 12Z THURSDAY. A MODEST LOW
LEVEL JET SURGING AHEAD OF THE LOW WILL ADVECT INCREASING LOW
LEVEL MOISTURE ACROSS THE OHIO VALLEY AND TOWARD THE LOWER LAKES
BY THURSDAY MORNING...BUT THE LATEST SREF GUIDANCE SUGGESTS THAT
THE BULK OF THE RAIN FORMING AHEAD OF THE LOW WILL STAY MAINLY
WEST OF OUR CWA THROUGH 600 AM.
THE SOUTHERLY FLOW AHEAD OF THE LOW AND ITS TRAILING COLD FRONT
WILL ALLOW MOST AREAS TO WARM INTO THE LOWER 40S...WITH THE
COOLEST READINGS (MID 30S) EXPECTED ACROSS THE HIGHER ELEVATIONS
EAST OF LAKE ONTARIO.
IN TERMS OF QPF...AVERAGE BASIN RAINFALL TOTALS ARE EXPECTED TO
REMAIN UNDER 0.25 INCH THROUGH THURSDAY.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
THE SURFACE LOW WILL BE IN THE PROCESS OF LIFTING ACROSS SOUTHERN
ONTARIO/QUEBEC AT THE START OF THE PERIOD. COLDER AIR WORKING INTO
THE REGION ON THE BACK SIDE OF THE LOW WILL BE TRANSITIONING
PRECIPITATION OVER TO SNOW IN THE WEST...WHILE EASTERN SECTIONS
SHOULD STILL BE RAIN. EASTERN SECTIONS SHOULD TRANSITION TO SNOW
OVERNIGHT WITH SOME POTENTIAL FOR UPSLOPE ENHANCEMENT ALONG THE
WESTERN SOUTHERN TIER AND TUG HILL. THE POTENTIAL FOR LAKE EFFECT
SNOW SHOULD INCREASE FRIDAY NIGHT THROUGH SATURDAY AS A CLIPPER TYPE
SHORTWAVE DROPS DOWN ACROSS THE LOWER LAKES. THIS WAVE WILL INCREASE
THE MOISTURE DEPTH ALONG WITH OVER-LAKE INSTABILITY WITH 850 MB
TEMPERATURES COOLING GRADUALLY TO AROUND -12C. BEST CHANCES FOR
MINOR ACCUMULATING SNOWS WILL BE ALONG THE TUG HILL AND ACROSS THE
HIGHER TERRAIN OF THE SOUTHERN TIER.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE FORECAST FOR THE END PART OF THE WEEKEND WILL CENTER AROUND HOW
THE SOUTHERN STREAM SYSTEM EVOLVES AS IT LIFTS OUT OF THE GULF
COASTAL STATES. THERE STILL EXISTS QUITE A BIT OF MODEL SPREAD WITH
HOW THIS SYSTEM WILL INTERACT WITH THE NORTHERN STREAM ENERGY. STILL
A FEW MODEL RUNS OUT BEFORE THIS GETS BETTER RESOLVED. A COMPROMISE
FORECAST FOR NOW SEEMS TO MOST REASONABLE WAY TO GO WITH A FORECAST
TREND TO A MORE SOUTHERN SOLUTIONS MORE IN LINE WITH THE ECMWF. THIS
MORE SOUTHERN SOLUTION WOULD KEEP NEARLY ALL INTERESTING WEATHER
SOUTH OF THE AREA. ONCE THIS SYSTEM EXITS A BROAD RIDGE WILL DEVELOP
ACROSS THE REGION FOR THE EARLY PART OF NEXT WEEK...PROVIDING A
PERIOD OF FAIR WEATHER. NEXT SIGNIFICANT WAVE LOOKS TO CROSS THE
REGION BY THE END OFF THE PERIOD.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL BRIEFLY RIDGE ACROSS THE REGION...FOLLOWED BY
AN AREA OF WEAK LOW PRESSURE WHICH WILL TRACK TO THE WEST ACROSS
THE CENTRAL LAKES REGION.
FOR THE 00Z TAFS...MOST SITES HAVE IMPROVED TO VFR EITHER THROUGH
LIFTING OR SCATTERING CLOUDS. FOLLOWING UPSTREAM TRENDS...JHW WILL
LIKELY IMPROVE SOON...WITH MAINLY VFR CONDITIONS EXPECTED THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE. TREND UP
START TIME SLIGHTLY...BUT MAINTAIN THINKING THAT A SE FLOW AHEAD
OF THE LOW SHOULD HELP KEEP CIGS UP AT BUF/IAG/ROC UNTIL THE WIND
SHIFT AS THE LOW PASSES. THEN EXPECT IFR/MVFR CIGS WITH THE WIND SHIFT.
AT JHW...CIGS SHOULD LOWER QUICKER...WHERE DOWNSLOPING WILL NOT BE
AN ISSUE. THE LATER TIMING FOR ART SHOULD KEEP VFR CONDITIONS
THERE THE LONGEST.
THERE ARE A COUPLE ISSUES TO WATCH ON THURSDAY MORNING.
FIRST...WINDS ALOFT INCREASE TO 35 OR 40 KTS...RESULTING IN
MARGINAL WIND SHEAR. BASED ON FORECAST WIND PROFILES...HAVE ADDED
LLWS TO JHW ONLY...WITH SHEAR A BIT SHY OF CRITERIA AT OTHER
SITES. WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF A BRIEF
PERIOD OF -FZRA OR PL AT JHW AT THE ONSET...DEPENDING ON HOW MUCH
TEMPERATURES DROP AHEAD OF THE RAIN.
OUTLOOK...
THURSDAY NIGHT...MAINLY IFR IMPROVING TO MVFR.
FRIDAY...MAINLY VFR WITH MVFR IN SNOW SHOWERS EAST OF LAKE ONTARIO.
SATURDAY...MVFR IN OCNL -SHSN.
SUNDAY...MAINLY VFR.
MONDAY...VFR.
&&
.MARINE...
HIGH PRESSURE OVER PA WILL SLIDE TO THE EAST COAST TONIGHT WHILE LOW
PRESSURE MOVES OUT OF THE SOUTHERN PLAINS. THE CIRCULATION BETWEEN
THESE TWO SYSTEMS WILL RESULT IN A SOUTHERLY FLOW ACROSS THE LAKES
TONIGHT AND THURSDAY. THE WINDS MAY PICK UP ENOUGH TO PRODUCE SMALL
CRAFT ADVISORY CONDITIONS ALONG THE FAR EASTERN NEARSHORES OF LAKE
ONTARIO LATE IN THE DAY. AS THE LOW CONTINUES TO TRACK SOUTH OF
JAMES BAY THURSDAY NIGHT AND FRIDAY...A WESTERLY FLOW OF COLDER AIR
WILL FOLLOW...RESULTING IN A GOOD CHANCE FOR SMALL CRAFT ADVISORY
CONDITIONS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...APFFEL/TJP
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
910 PM EST WED FEB 15 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST AND OFFSHORE OVERNIGHT. A WEAK
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
REGION THURSDAY AFTERNOON AND EVENING.
&&
.NEAR TERM /TONIGHT/...
AS OF 910 PM WEDNESDAY...
A DRY AIRMASS IS IN PLACE THIS EVENING ACROSS CENTRAL NC
AS A 1026 MB SURFACE HIGH WAS CENTERED OVER THE REGION.
THICKENING WAA MID/UPPER LEVEL CLOUD CANOPY ASSOCIATED WITH
A DAMPENING WAVE OVER MISSOURI HAS ALREADY ADVANCED EASTWARD
ACROSS WESTERN HALF OF THE STATE....AND WILL CONTINUE TO SPREAD EAST
OVERNIGHT AS THE WAVE REACHES THE OHIO VALLEY/LOWER GREAT LAKES BY
THURSDAY MORNING. HOWEVER ANY MEASURABLE RAIN SHOULD HOLD OFF UNTIL
AFTER DAYBREAK AS THE ANTECEDENT DRY LOW-LEVEL AIRMASS(CHARACTERIZED
BY SFC DEWPOINTS IN THE 25 TO 35F RANGE)WILL UNDERGO ONLY SLIGHT
MODERATION AS SURFACE HIGH SHIFTS OFFSHORE LATE.
BASED ON LATEST SATELLITE AND OBSERVATIONS TRENDS...RADIATIONAL
COOLING HAS ALREADY CEASED ACROSS THE WESTERN PIEDMONT...WITH
ANOTHER 2 TO 3 HOURS OF COOLING IN THE EAST BEFORE IT IS MET WITH
THE SAME FATE. FORECAST MINS TONIGHT LOOK A GOOD 4 TO 7 DEGREES TOO
COOL IN THE WEST...2 TO 4 DEGREES TOO WARM ACROSS CENTRAL AREAS.
NORTHERN COASTAL PLAIN COUNTIES COULD STILL POTENTIALLY REACH
PROJECTED LOWS OF UPPER 30S IN THE NEXT COUPLE OF HOUR.
OVERNIGHT LOWS FROM NEAR 50 WEST TO UPPER 30S NORTHEAST.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 215 PM WEDNESDAY...
HIGH CONFIDENCE IN RAIN ON THURSDAY...LOW CONFIDENCE IN AMOUNT.
MODELS ARE IN GOOD OVERALL AGREEMENT IN THE FORECAST OF THE CURRENT
MID-UPPER TROUGH CURRENTLY MOVING OUT OF TEXAS AND OKLAHOMA.
CONVECTION HAS BEEN BLOSSOMING OVER SE TEXAS THIS AFTERNOON. THIS
HAS BEEN HANDLED WELL THUS FAR BY THE 12Z GFS. ALL MODELS GENERALLY
SHOW THE MID-UPPER TROUGH PROGRESSING QUICKLY ENE TOWARD OUR REGION
TONIGHT AND THURSDAY. THE AFOREMENTIONED 12Z/GFS HAS PICKED UP ON
THE CONVECTION FLARING UP ALREADY OVER SE TEXAS... AND HAS THIS
CONVECTION SPREADING ENE ACROSS MS/AL AND GA OVERNIGHT THROUGH
12Z/THU. FROM THERE... MODELS DIVERGE ON POP/QPF OVER NC THURSDAY.
THE LATEST GFS AND NOW THE LATEST EUROPEAN MODELS DEPICT ALMOST
DOUBLE THE QPF OR RAINFALL AMOUNTS ACROSS MUCH OF OUR REGION THAN
THE 12Z/NAM WITH THE EVENT. YET... THE HIGH RESOLUTION MODELS IN
PARTICULAR THE SPC WRF AND THE HRRR DEPICT MINIMAL QPF OVER CENTRAL
NC. THIS LACK OF QPF MAY BE THE WAY TO GO GIVEN THE NCEP MODELS
TYPICAL FAILURE IN CAPTURING GULF COAST CONVECTION AND ITS ROLE IN
DISRUPTING MOISTURE TRANSPORT INTO THE CAROLINAS UPSTREAM.
HOWEVER... THE LATEST EURO SUPPORTS HEAVIER QPF ACROSS CENTRAL NC
WITH THE CONVECTION FALLING APART AS IT SWEEPS ACROSS THE DEEP SOUTH
LATE TONIGHT AND THURSDAY. WITH THIS IN MIND... WE WILL KEEP CURRENT
CATEGORICAL POP IN PLACE... AND CONTINUE TO FORECAST RAINFALL
AMOUNTS OF AROUND 0.25. IF CONVECTION DOES NOT SPREAD EAST ACROSS
GA... AND THE DEEP MOISTURE TRANSPORT (35-45KT SSW FLOW 925-850MB)
IN THE MODELS IS NOT DISRUPTED... THEN QPF OF UP TO A HALF INCH
WOULD BE LIKELY. HIGHS SHOULD SHOW QUITE A RANGE WITH SOME LIGHT
RAIN IN THE WEST EARLY... KEEPING HIGHS IN THE 50-55 RANGE. HIGHS
SHOULD REACH THE LOWER 60S AROUND FAY TO GSB.
THURSDAY NIGHT... SHOWERS WILL QUICKLY MOVE EAST WITH THE TROUGH...
BUT LOW LEVEL MOISTURE WILL LAG PER THE LATEST MODELS. DEPENDING ON
IF THE GROUND GETS WET OR NOT... FOG WILL/WILL NOT BE AN ISSUE. IF
WE SQUEEZE OUT 0.10 OR SO... THEN FOG WILL BE LIKELY. OTHERWISE...
PARTLY CLOUDY WITH LOWS 35-40.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
A DEAMPLIFYING SHORTWAVE PROGRESSING EAST THROUGH THE MID-ATLANTIC
ON THU (AND ITS ATTENDANT SFC LOW DEVELOPING OVER THE CAROLINAS)
WILL MOVE OFFSHORE THU NIGHT. EXPECT CLEAR SKIES EVERYWHERE BY 12Z
FRI MORNING AS DRY HIGH PRESSURE BUILDS INTO THE AREA FROM THE W/NW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE MID-ATLANTIC/CAROLINAS
FROM DURING THE DAY FRI...AND IS PROGGED TO BE CENTERED NEAR THE
MID-ATLANTIC COAST BY 12Z SAT. UNIFORM/FLAT FLOW ALOFT IS EXPECTED
OVER THE CAROLINAS FRI THROUGH FRI NIGHT. WITH THE ABOVE IN MIND...
EXPECT SUNNY SKIES DURING THE DAY FRI. 1000-850 MB THICKNESSES ARE
PROGGED TO RANGE FROM 1335-1345 METERS N-S ON FRIDAY...SUGGESTING
HIGHS RANGING FROM 59-65F OR SO...WARMEST NEAR THE SC BORDER. A LOW
PRESSURE SYSTEM IS EXPECTED TO BEGIN DEVELOPING IN VICINITY OF THE
TX GULF COAST LATE FRI NIGHT AS SHORTWAVE ENERGY CURRENTLY
PROGRESSING SOUTH THROUGH CA/NV AMPLIFIES INTO A CLOSED UPPER LOW
AND STARTS TRACKING EAST TOWARD WESTERN TX. IT IS POSSIBLE THAT SOME
UPPER LEVEL CLOUD COVER COULD MOVE INTO THE CAROLINAS DOWNSTREAM OF
PRECIPITATION EXPECTED ALONG THE GULF COAST STATES LATE FRI NIGHT...
HOWEVER...THE LATEST MODEL GUIDANCE INDICATES THAT MOST OF THE
INCREASE IN MID/UPPER LEVEL CLOUD COVER SHOULD HOLD OFF UNTIL AFTER
SUNRISE SAT (WHEN PRECIP IS EXPECTED TO BLOSSOM OVER THE DEEP
SOUTH)...WITH MINIMAL IMPACT ON LOW TEMPS. WILL FCST LOWS RANGING
FROM THE LOWER/MID 30S TO UPPER 30S SAT MORNING...COLDEST IN THE
TYPICAL SHELTERED/LOW-LYING AREAS...PARTICULARLY IN EAST/NE PORTIONS
OF THE AREA.
SATURDAY THROUGH SUNDAY NIGHT:
SIGNIFICANT UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF THE
AFOREMENTIONED STORM SYSTEM AS IT TRACKS FROM THE TX GULF COAST
THROUGH THE DEEP SOUTH AND INTO THE CAROLINAS/MID-ATLANTIC THIS
WEEKEND. THE OPERATIONAL MODELS ARE HAVING A VERY DIFFICULT TIME
DETERMINING HOW MUCH (IF ANY) PHASING WILL OCCUR BETWEEN THE
SHORTWAVE ENERGY EJECTING EASTWARD FROM TX INTO THE DEEP SOUTH
SAT/SAT NIGHT AND NORTHERN STREAM SHORTWAVE ENERGY DIVING SOUTHEAST
FROM WESTERN CANADA THROUGH THE UPPER MIDWEST/GREAT LAKES INTO THE
TN/OH VALLEYS. EXACTLY HOW THE NORTHERN/SOUTHERN STREAM SHORTWAVE
ENERGY INTERACTS WILL IN LARGE PART DETERMINE THE SUBSEQUENT
EVOLUTION OF THE LOW PRESSURE SYSTEM OVER AND OFFSHORE THE CAROLINAS
THIS WEEKEND. AT THIS TIME...THE ECMWF IS STILL THE PREFERRED MODEL
OF CHOICE GIVEN ITS CONSISTENCY AND BETTER TRACK RECORD...ALTHOUGH
CONSIDERABLE UNCERTAINTY PERSISTS EVEN WITH THE ECMWF DUE TO THE
COMPLEX NATURE OF THE UPPER LEVEL PATTERN AND THAT SOME OF THE KEY
FEATURES WILL NOT BE SAMPLED WELL BY THE RAOB NETWORK UNTIL LATER
THIS WEEK. WITH THE ABOVE IN MIND...ASIDE FROM INTRODUCING PRECIP
CHANCES FROM SW-NE SATURDAY AFTERNOON (A BIT EARLIER THAN PREVIOUSLY
INDICATED)...WILL MAKE FEW CHANGES TO THE CURRENT FORECAST FOR
SATURDAY THROUGH SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY:
THERE IS REASONABLE AGREEMENT AMONG THE LONG TERM MODELS THAT DRY
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS IN THE WAKE OF THE LOW
PRESSURE SYSTEM DEPARTING THE CAROLINA COAST SUN/SUN NIGHT...AND AT
THIS TIME EXPECT DRY CONDITIONS WITH SUNNY SKIES AND HIGHS NEAR
NORMAL IN THE LOWER/MID 50S...WITH LOWS MON NIGHT IN THE LOWER 30S.
UNCERTAINTY GROWS AGAIN BY MID-WEEK IN ADVANCE OF THE NEXT SYSTEM
EXPECTED TO APPROACH THE AREA FROM THE WEST LATE TUE NIGHT INTO WED.
AT THIS TIME...WILL KEEP THE FCST DRY ON TUE WITH HIGH PRESSURE
SLOWLY SHIFTING OFFSHORE THE CAROLINAS. A WARM/MOIST SOUTHERLY
RETURN FLOW IS PROGGED TO DEVELOP BY TUE NIGHT/WED AS HIGH PRESSURE
MOVES OFFSHORE IN ADVANCE OF THE NEXT SYSTEM PROGGED TO APPROACH THE
AREA BY MID-WEEK...AND WILL INTRODUCE A 30% CHANCE FOR SHOWERS ON
WED. -VINCENT
&&
.AVIATION /00Z THURSDAY THROUGH SUNDAY/...
AS OF 645 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH AT LEAST DAYBREAK ON
THURSDAY...HOWEVER MID/HIGH CLOUDS WILL OVERSPREAD THE REGION
THROUGH THE OVERNIGHT HOURS AHEAD OF AN APPROACHING SYSTEM. CLOUDS
WILL THICKEN AND LOWER AS RAIN SPREADS INTO THE FORECAST AREA FROM
WEST TO EAST...LIKELY BEGINNING BETWEEN 12-15Z ACROSS THE WEST (KINT
AND KGSO) AND THEN SPREADING EAST OVER THE NEXT SEVERAL HOURS.
CIGS/VSBYS WILL BECOME IFR/LIFR WITH RAIN AND FOG AND THEN PERSIST
MUCH OF THE DAY THURSDAY. THE PRECIP IS EXPECTED TO COME TO AN END
FROM WEST TO EAST DURING THE LATE AFTERNOON/EVENING HOURS...WITH THE
EASTERN TAF SITES LIKELY STILL EXPERIENCING RAIN BY THE END OF THE
CURRENT TAF PERIOD. NEVERTHELESS...CIGS/VSBYS ARE EXPECTED TO REMAIN
IN THE IFR RANGE AREAWIDE THROUGH AT LEAST THE END OF THE CURRENT
TAF PERIOD (I.E. 00Z FRIDAY).
OUTLOOK: AREAS OF MVFR/IFR VSBYS IN FOG ARE EXPECTED THURSDAY NIGHT
AFTER THE CIGS LIFT DURING THE EVENING. THE FOG IS EXPECTED TO LIFT
EARLY FRIDAY...WITH VFR CONDITIONS RETURNING BY 15Z FRIDAY MORNING.
THERE IS AN INCREASING CHANCE OF WIDESPREAD RAIN WITH IFR CIGS/VSBYS
AS ANOTHER SYSTEM APPROACHES OUR REGION THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...CBL
SHORT TERM...BADGETT
LONG TERM...VINCENT
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
700 PM EST WED FEB 15 2012
.SYNOPSIS...
HIGH PRESSURE WILL BE OVERHEAD TODAY THEN SHIFT EAST TONIGHT. A WEAK
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
REGION THURSDAY AFTERNOON AND EVENING.
&&
.NEAR TERM /TONIGHT/...
AS OF 215 PM WEDNESDAY...
THE SKIES CONTINUED SUNNY THIS AFTERNOON AS HIGH PRESSURE REMAINED
IN CONTROL (CENTERED OVER VA/NC/SC). HIGHS 60-65 THIS AFTERNOON WITH
LIGHT AND VARIABLE WINDS.
IT NOW APPEARS THAT THE SIGNIFICANT CLOUDINESS WILL
DEVELOP/OVERSPREAD OUR REGION LATER TONIGHT. THIS WILL GIVE MOST
AREAS A CHANCE AT EXCELLENT RADIATIONAL COOLING DURING THE EVENING
BEFORE THE CLOUDS BECOME THICK ENOUGH TO SLOW THE COOLING PROCESS.
LOWS SHOULD OCCUR BETWEEN LATE EVENING AND 200 AM TO 400 AM...
BEFORE LEVELING OFF. THE CURRENT PATTERN OF THE SKIES REMAINING
CLEAR LONGER IN THE EAST FAVORS A NON-CLIMATOLOGICAL GEOGRAPHICAL
PRESENTATION OF MINIMUM TEMPERATURES OVERNIGHT... WITH READINGS
30-35 IN THE NE AROUND ROCKY MOUNT AND HALIFAX... TO READINGS AT OR
POSSIBLY ABOVE 40 IN THE YADKIN VALLEY OF THE WESTERN PIEDMONT.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 215 PM WEDNESDAY...
HIGH CONFIDENCE IN RAIN ON THURSDAY...LOW CONFIDENCE IN AMOUNT.
MODELS ARE IN GOOD OVERALL AGREEMENT IN THE FORECAST OF THE CURRENT
MID-UPPER TROUGH CURRENTLY MOVING OUT OF TEXAS AND OKLAHOMA.
CONVECTION HAS BEEN BLOSSOMING OVER SE TEXAS THIS AFTERNOON. THIS
HAS BEEN HANDLED WELL THUS FAR BY THE 12Z GFS. ALL MODELS GENERALLY
SHOW THE MID-UPPER TROUGH PROGRESSING QUICKLY ENE TOWARD OUR REGION
TONIGHT AND THURSDAY. THE AFOREMENTIONED 12Z/GFS HAS PICKED UP ON
THE CONVECTION FLARING UP ALREADY OVER SE TEXAS... AND HAS THIS
CONVECTION SPREADING ENE ACROSS MS/AL AND GA OVERNIGHT THROUGH
12Z/THU. FROM THERE... MODELS DIVERGE ON POP/QPF OVER NC THURSDAY.
THE LATEST GFS AND NOW THE LATEST EUROPEAN MODELS DEPICT ALMOST
DOUBLE THE QPF OR RAINFALL AMOUNTS ACROSS MUCH OF OUR REGION THAN
THE 12Z/NAM WITH THE EVENT. YET... THE HIGH RESOLUTION MODELS IN
PARTICULAR THE SPC WRF AND THE HRRR DEPICT MINIMAL QPF OVER CENTRAL
NC. THIS LACK OF QPF MAY BE THE WAY TO GO GIVEN THE NCEP MODELS
TYPICAL FAILURE IN CAPTURING GULF COAST CONVECTION AND ITS ROLE IN
DISRUPTING MOISTURE TRANSPORT INTO THE CAROLINAS UPSTREAM.
HOWEVER... THE LATEST EURO SUPPORTS HEAVIER QPF ACROSS CENTRAL NC
WITH THE CONVECTION FALLING APART AS IT SWEEPS ACROSS THE DEEP SOUTH
LATE TONIGHT AND THURSDAY. WITH THIS IN MIND... WE WILL KEEP CURRENT
CATEGORICAL POP IN PLACE... AND CONTINUE TO FORECAST RAINFALL
AMOUNTS OF AROUND 0.25. IF CONVECTION DOES NOT SPREAD EAST ACROSS
GA... AND THE DEEP MOISTURE TRANSPORT (35-45KT SSW FLOW 925-850MB)
IN THE MODELS IS NOT DISRUPTED... THEN QPF OF UP TO A HALF INCH
WOULD BE LIKELY. HIGHS SHOULD SHOW QUITE A RANGE WITH SOME LIGHT
RAIN IN THE WEST EARLY... KEEPING HIGHS IN THE 50-55 RANGE. HIGHS
SHOULD REACH THE LOWER 60S AROUND FAY TO GSB.
THURSDAY NIGHT... SHOWERS WILL QUICKLY MOVE EAST WITH THE TROUGH...
BUT LOW LEVEL MOISTURE WILL LAG PER THE LATEST MODELS. DEPENDING ON
IF THE GROUND GETS WET OR NOT... FOG WILL/WILL NOT BE AN ISSUE. IF
WE SQUEEZE OUT 0.10 OR SO... THEN FOG WILL BE LIKELY. OTHERWISE...
PARTLY CLOUDY WITH LOWS 35-40.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
A DEAMPLIFYING SHORTWAVE PROGRESSING EAST THROUGH THE MID-ATLANTIC
ON THU (AND ITS ATTENDANT SFC LOW DEVELOPING OVER THE CAROLINAS)
WILL MOVE OFFSHORE THU NIGHT. EXPECT CLEAR SKIES EVERYWHERE BY 12Z
FRI MORNING AS DRY HIGH PRESSURE BUILDS INTO THE AREA FROM THE W/NW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE MID-ATLANTIC/CAROLINAS
FROM DURING THE DAY FRI...AND IS PROGGED TO BE CENTERED NEAR THE
MID-ATLANTIC COAST BY 12Z SAT. UNIFORM/FLAT FLOW ALOFT IS EXPECTED
OVER THE CAROLINAS FRI THROUGH FRI NIGHT. WITH THE ABOVE IN MIND...
EXPECT SUNNY SKIES DURING THE DAY FRI. 1000-850 MB THICKNESSES ARE
PROGGED TO RANGE FROM 1335-1345 METERS N-S ON FRIDAY...SUGGESTING
HIGHS RANGING FROM 59-65F OR SO...WARMEST NEAR THE SC BORDER. A LOW
PRESSURE SYSTEM IS EXPECTED TO BEGIN DEVELOPING IN VICINITY OF THE
TX GULF COAST LATE FRI NIGHT AS SHORTWAVE ENERGY CURRENTLY
PROGRESSING SOUTH THROUGH CA/NV AMPLIFIES INTO A CLOSED UPPER LOW
AND STARTS TRACKING EAST TOWARD WESTERN TX. IT IS POSSIBLE THAT SOME
UPPER LEVEL CLOUD COVER COULD MOVE INTO THE CAROLINAS DOWNSTREAM OF
PRECIPITATION EXPECTED ALONG THE GULF COAST STATES LATE FRI NIGHT...
HOWEVER...THE LATEST MODEL GUIDANCE INDICATES THAT MOST OF THE
INCREASE IN MID/UPPER LEVEL CLOUD COVER SHOULD HOLD OFF UNTIL AFTER
SUNRISE SAT (WHEN PRECIP IS EXPECTED TO BLOSSOM OVER THE DEEP
SOUTH)...WITH MINIMAL IMPACT ON LOW TEMPS. WILL FCST LOWS RANGING
FROM THE LOWER/MID 30S TO UPPER 30S SAT MORNING...COLDEST IN THE
TYPICAL SHELTERED/LOW-LYING AREAS...PARTICULARLY IN EAST/NE PORTIONS
OF THE AREA.
SATURDAY THROUGH SUNDAY NIGHT:
SIGNIFICANT UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF THE
AFOREMENTIONED STORM SYSTEM AS IT TRACKS FROM THE TX GULF COAST
THROUGH THE DEEP SOUTH AND INTO THE CAROLINAS/MID-ATLANTIC THIS
WEEKEND. THE OPERATIONAL MODELS ARE HAVING A VERY DIFFICULT TIME
DETERMINING HOW MUCH (IF ANY) PHASING WILL OCCUR BETWEEN THE
SHORTWAVE ENERGY EJECTING EASTWARD FROM TX INTO THE DEEP SOUTH
SAT/SAT NIGHT AND NORTHERN STREAM SHORTWAVE ENERGY DIVING SOUTHEAST
FROM WESTERN CANADA THROUGH THE UPPER MIDWEST/GREAT LAKES INTO THE
TN/OH VALLEYS. EXACTLY HOW THE NORTHERN/SOUTHERN STREAM SHORTWAVE
ENERGY INTERACTS WILL IN LARGE PART DETERMINE THE SUBSEQUENT
EVOLUTION OF THE LOW PRESSURE SYSTEM OVER AND OFFSHORE THE CAROLINAS
THIS WEEKEND. AT THIS TIME...THE ECMWF IS STILL THE PREFERRED MODEL
OF CHOICE GIVEN ITS CONSISTENCY AND BETTER TRACK RECORD...ALTHOUGH
CONSIDERABLE UNCERTAINTY PERSISTS EVEN WITH THE ECMWF DUE TO THE
COMPLEX NATURE OF THE UPPER LEVEL PATTERN AND THAT SOME OF THE KEY
FEATURES WILL NOT BE SAMPLED WELL BY THE RAOB NETWORK UNTIL LATER
THIS WEEK. WITH THE ABOVE IN MIND...ASIDE FROM INTRODUCING PRECIP
CHANCES FROM SW-NE SATURDAY AFTERNOON (A BIT EARLIER THAN PREVIOUSLY
INDICATED)...WILL MAKE FEW CHANGES TO THE CURRENT FORECAST FOR
SATURDAY THROUGH SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY:
THERE IS REASONABLE AGREEMENT AMONG THE LONG TERM MODELS THAT DRY
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS IN THE WAKE OF THE LOW
PRESSURE SYSTEM DEPARTING THE CAROLINA COAST SUN/SUN NIGHT...AND AT
THIS TIME EXPECT DRY CONDITIONS WITH SUNNY SKIES AND HIGHS NEAR
NORMAL IN THE LOWER/MID 50S...WITH LOWS MON NIGHT IN THE LOWER 30S.
UNCERTAINTY GROWS AGAIN BY MID-WEEK IN ADVANCE OF THE NEXT SYSTEM
EXPECTED TO APPROACH THE AREA FROM THE WEST LATE TUE NIGHT INTO WED.
AT THIS TIME...WILL KEEP THE FCST DRY ON TUE WITH HIGH PRESSURE
SLOWLY SHIFTING OFFSHORE THE CAROLINAS. A WARM/MOIST SOUTHERLY
RETURN FLOW IS PROGGED TO DEVELOP BY TUE NIGHT/WED AS HIGH PRESSURE
MOVES OFFSHORE IN ADVANCE OF THE NEXT SYSTEM PROGGED TO APPROACH THE
AREA BY MID-WEEK...AND WILL INTRODUCE A 30% CHANCE FOR SHOWERS ON
WED. -VINCENT
&&
.AVIATION /00Z THURSDAY THROUGH SUNDAY/...
AS OF 645 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH AT LEAST DAYBREAK ON
THURSDAY...HOWEVER MID/HIGH CLOUDS WILL OVERSPREAD THE REGION
THROUGH THE OVERNIGHT HOURS AHEAD OF AN APPROACHING SYSTEM. CLOUDS
WILL THICKEN AND LOWER AS RAIN SPREADS INTO THE FORECAST AREA FROM
WEST TO EAST...LIKELY BEGINNING BETWEEN 12-15Z ACROSS THE WEST (KINT
AND KGSO) AND THEN SPREADING EAST OVER THE NEXT SEVERAL HOURS.
CIGS/VSBYS WILL BECOME IFR/LIFR WITH RAIN AND FOG AND THEN PERSIST
MUCH OF THE DAY THURSDAY. THE PRECIP IS EXPECTED TO COME TO AN END
FROM WEST TO EAST DURING THE LATE AFTERNOON/EVENING HOURS...WITH THE
EASTERN TAF SITES LIKELY STILL EXPERIENCING RAIN BY THE END OF THE
CURRENT TAF PERIOD. NEVERTHELESS...CIGS/VSBYS ARE EXPECTED TO REMAIN
IN THE IFR RANGE AREAWIDE THROUGH AT LEAST THE END OF THE CURRENT TAF
PERIOD (I.E. 00Z FRIDAY).
OUTLOOK: AREAS OF MVFR/IFR VSBYS IN FOG ARE EXPECTED THURSDAY NIGHT
AFTER THE CIGS LIFT DURING THE EVENING. THE FOG IS EXPECTED TO LIFT
EARLY FRIDAY...WITH VFR CONDITIONS RETURNING BY 15Z FRIDAY MORNING.
THERE IS AN INCREASING CHANCE OF WIDESPREAD RAIN WITH IFR CIGS/VSBYS
AS ANOTHER SYSTEM APPROACHES OUR REGION THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...VINCENT
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1032 PM EST WED FEB 15 2012
.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT WILL BRING RAIN TO THE REGION LATE
TONIGHT AND THROUGH MID DAY THURSDAY. HIGH PRESSURE WILL THEN
BUILD IN THROUGH FRIDAY. ANOTHER COLD FRONT WILL MOVE THROUGH ON
SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
ONE BAND OF SHOWERS WILL CONTINUE TO AFFECT THE NORTHERN CWA OVER
THE NEXT HOUR OR TWO. ANOTHER AREA OF LIGHT TO MODERATE SHOWERS
IS CURRENTLY DEVELOPING OVER SOUTHERN INDIANA AND NORTHERN
KENTUCKY ON THE NOSE OF A LOW LEVEL JET. LATEST RUC SHOWS THIS
JET INTENSIFYING A BIT AS IT PIVOTS INTO THE SOUTHWESTERN PORTION
OF CWA BY 09Z. IT THEN WEAKENS AS IT MEANDERS NORTHEAST INTO
CENTRAL OHIO BY DAYBREAK. EXPECT SHOWERS TO BECOME STEADIER LATE
TONIGHT AS THE JET DEVELOPS AND MOVES ACROSS THE CWA...AND AS LOW
PRESSURE AND ASSOCIATED COLD FRONT APPROACH FROM THE SOUTHWEST.
MODELS IN GOOD AGREEMENT WITH SHOWERS TAPERING OFF FAIRLY QUICKLY
FROM WEST TO EAST WITH FRONTAL PASSAGE BY LATE THURSDAY MORNING.
ADJUSTED TONIGHT/S TEMPERATURES JUST SLIGHTLY BASED ON CURRENT
TRENDS. WILL SEE SOME RISE IN TEMPS DURING THE AFTERNOON
ESPECIALLY AS CLOUDS START BREAKING UP. BUT WENT SLIGHTLY BELOW
GUIDANCE FOR HIGHS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL MOVE ACROSS THE REGION THROUGH THE PERIOD.
EXPECT LITTLE IN THE WAY OF CLOUD COVER UNTIL POSSIBLY LATE FRIDAY
NIGHT WITH THE APPROACH OF THE NEXT SYSTEM. STAYED CLOSE TO MOS
CONSENSUS FOR LOWS BUT WENT SLIGHTLY COOLER FOR HIGHS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS DISAGREE FOR THE SATURDAY THROUGH SATURDAY NIGHT TIME FRAME.
BOTH THE GFS AND THE ECMWF HAVE A SOUTHERN SYSTEM AND A NORTHERN
SYSTEM. THE ECMWF KEEPS THESE SYSTEMS SEPARATE WHILE THE GFS TRIES
TO PHASE THESE TWO FEATURES AND THEREFORE BRINGS PRECIPITATION INTO
THE AREA. WENT CLOSER TO THE ECMWF SOLUTION HOWEVER DID NOT WANT TO
TOTALLY DISCOUNT THE GFS AT THIS POINT IN TIME. DUE TO
THIS...LIMITED PRECIPITATION CHANCES TO A CHANCE ON SATURDAY AND A
SLIGHT CHANCE SATURDAY NIGHT. PRECIPITATION WILL TAPER OFF SATURDAY
NIGHT.
DRIER AND COOLER CONDITIONS WILL BE PRESENT ACROSS THE FA FOR
SUNDAY. SKIES WILL BE MOSTLY CLEAR SUNDAY NIGHT WITH HIGH PRESSURE
ACROSS THE AREA. WITH LIGHT WINDS AND CLEAR SKIES DROPPED
TEMPERATURES DOWN INTO THE LOWER 20S. SOUTHERLY FLOW WILL ALLOW FOR
TEMPERATURES TO WARM DURING THE DAY ON MONDAY INTO THE 40S.
THE NEXT SYSTEM WILL BEGIN TO BRING RAIN TO THE AREA TUESDAY
AFTERNOON. BETTER RAIN CHANCES WILL OCCUR TUESDAY NIGHT INTO
WEDNESDAY AS THE AREA OF LOW PRESSURE NEARS THE FA.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
INITIAL WAVE OF SHRA PUSHINGH THROUGH THE AREA FROM ISENTROPIC
LIFT AHEAD OF MAIN SHORTWAVE POISED TO PUSH INTO AREA LATER
TONIGHT. I`M STILL CARRYING THIS INITIAL SHOT AS VCSH...AS IT WILL
BE MAINLY IN BANDS OF LIGHT VFR PRECIP. FORCING ASSOC WITH
APPROACHING SHORTWAVE OVERNIGHT IS BEST MOSTLY NORTH OF THE TAF
SITES...WITH KDAY BEING THE POSSIBLE EXCEPTION. HAVE GENERALLY
STUCK WITH MVFR CIGS AND VSBYS ONCE SHOWERS BEGIN...ALTHOUGH THERE
IS SOME POTENTIAL FOR CIGS NEAR 1000 FEET IN THE 11-14Z TIMEFRAME.
AS FRONT PUSHES THROUGH IN THE LATE MORNING...SOME LINGERING
SPOTTY SHOWERS THROUGH ABOUT 18-19Z. MVFR CIGS TO PERSIST IN
LINGERING LL MOISTURE BEHIND THE FRONT. IN THE WEST...PARTIAL
CLEARING AFTER 00Z...BUT AM CONCERNED THAT IF WINDS DIE DOWN
SUFFICIENTLY...THERE COULD BE SOME STRATUS DEVELOPING LATE
THURSDAY NIGHT.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KURZ
SHORT TERM...
LONG TERM...NOVAK
AVIATION...JDR
AREA FORECAST DISCUSSION
NWS NORMAN OK
1140 PM CST MON FEB 13 2012
.AVIATION...
DEVELOPMENT OF FOG AND LOW STRATUS IS WELL UNDERWAY ACROSS MUCH
OF OKLAHOMA AND PARTS OF WESTERN NORTH TEXAS. WHILE CIGS
CONTINUED TO ERODE ACROSS THE NORTHERN HALF OF OKLAHOMA...LIGHT
SOUTHEAST WINDS CAUSED LOW CIGS TO BUILD BACK INTO SOME AREAS.
IFR/LIFR CONDITIONS CAN BE EXPECTED AT MOST TERMINALS...WITH SOME
VSBYS AS LOW AS 1/4 MILE ALREADY BEING REPORTED ACROSS
CENTRAL/SOUTHERN OKLAHOMA. EXPECT TREND TO CONTINUE WITH DENSE
FOG BUILDING INTO MUCH OF OKLAHOMA AND WESTERN NORTH TEXAS. WITH
SLIGHTLY DRIER AIR AND WEST TO NORTHWEST WINDS ACROSS NORTHWEST
OKLAHOMA...KWWR AND KGAG WILL LIKELY REMAIN VFR
OVERNIGHT...THOUGH SOME PATCHY FOG CANNOT BE COMPLETELY RULED OUT
TOWARD SUNRISE. CONDITIONS WILL IMPROVE LATE TUESDAY MORNING AS
TEMPERATURES WARM AND WINDS SHIFT TO SOUTHERLY AHEAD OF AN
APPROACHING STORM SYSTEM.
&&
.PREV DISCUSSION... /ISSUED 946 PM CST MON FEB 13 2012/
UPDATE...
WITH LIGHT AND VARIABLE WINDS... MOSTLY CLEAR SKIES THIS
EVENING... AND MOIST AIR AT THE SURFACE... FOG IS EXPECTED TO
CONTINUE TO DEVELOP OVERNIGHT ACROSS PORTIONS OF THE FA... WITH
THE LEAST LIKELY AREA BEING NORTHWEST OK. DEWPOINT DEPRESSIONS ARE
ALREADY ZERO OR ONE IN MANY LOCATIONS. WITH THE LOW DEWPOINT
DEPRESSIONS AND VISIBILITIES ALREADY LESS THAN A MILE IN SOME
LOCATIONS WENT AHEAD AND ISSUED A DENSE FOG ADVISORY FOR PARTS OF
THE FA THROUGH 10 AM TUESDAY. THE ADVISORY MAY NEED TO BE EXTENDED
FURTHER WEST AND/OR NORTH LATER TONIGHT BUT FOR NOW OUTLINED THE
MOST LIKELY AREA. SOME LOCATIONS MAY ALSO DROP BELOW FREEZING
WHICH COULD CAUSE SOME FREEZING FOG LEAVING A GLAZE OF ICE ON
OBJECTS.
OTHERWISE...MADE SOME ADJUSTMENTS TO HOURLY GRIDS AND LOW
TEMPERATURES. THE FREEZING TEMPS MAY ALSO CAUSE SOME OF THE WET
ROADS TO ICE OVER AGAIN TONIGHT LEADING TO SLIPPERY ROADWAYS. WILL
SEND UPDATED PRODUCTS SHORTLY.
MAXWELL
PREV DISCUSSION... /ISSUED 549 PM CST MON FEB 13 2012/
AVIATION...
UPPER LEVEL SYSTEM THAT BROUGHT WINTRY WEATHER TO ALL TERMINALS
YESTERDAY HAS EXITED TO THE EAST. OVERNIGHT FORECAST IS SOMEWHAT
COMPLEX DUE TO ONGOING LOW CIGS OVER EASTERN OKLAHOMA AND
RESIDUAL SNOW PACK ACROSS MUCH OF CENTRAL AND SOUTHWEST OKLAHOMA.
AS WINDS DECREASE THROUGH 03Z...EXPECT COMBINATION OF SURFACE
MOISTURE AND COOLING TO ALLOW FOR WIDESPREAD FOG DEVELOPMENT.
VEERING SURFACE WINDS ACROSS WESTERN OKLAHOMA MAY INITIALLY LIMIT
LOW STRATUS FORMATION...BUT EXPECT LOW CIGS TO BUILD BACK IN LATE
TONIGHT. MOST TAF SITES WILL SEE MVFR/IFR AND POSSIBLY LIFR
VSBYS/CIGS THROUGH TUESDAY MORNING...EXCEPT KGAG AND KWWR...WHERE
SOME LOW LEVEL DRYING HAS OCCURRED.
PREV DISCUSSION... /ISSUED 307 PM CST MON FEB 13 2012/
DISCUSSION...
ALTHOUGH STILL SOMEWHAT GUSTY THIS AFTERNOON... WINDS WILL BECOME
LIGHT OVERNIGHT. BUT WITH THESE LIGHTER WINDS... THE REDEVELOPMENT
OF A MOIST BOUNDARY LAYER /AND FRESH SNOW IN SOME LOCATIONS/ WILL
LIKELY LEAD TO FOG DEVELOPMENT OVERNIGHT. THE RUC... HRRR AND NAM
ARE VERY AGGRESSIVE WITH FOG DEVELOPMENT OVERNIGHT AND A FOG
ADVISORY OR EVEN A FREEZING FOG ADVISORY MAY BE NEEDED
TONIGHT/TUESDAY MORNING BUT WILL NOT ISSUE WITH THIS PACKAGE YET.
WARMING TEMPERATURES ARE EXPECTED OVER THE NEXT COUPLE OF DAYS.
NEXT STORM SYSTEM WILL MOVE THROUGH THE PLAINS ON WEDNESDAY WITH
PRECIP MOVING EAST FOLLOWED BY GUSTY SOUTHWEST WINDS BEHIND A
DRYLINE. LATER IN THE FORECAST... HAVE ADDED LOW POPS FRIDAY
NIGHT WITH SOME QPF SIGNAL FROM BOTH GFS AND ECMWF... BUT
OTHERWISE NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE EXTENDED
PERIODS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 29 58 41 60 / 0 0 20 50
HOBART OK 28 54 39 61 / 0 0 10 20
WICHITA FALLS TX 34 65 46 69 / 0 0 30 40
GAGE OK 19 57 34 57 / 0 0 10 10
PONCA CITY OK 22 50 40 58 / 0 0 20 60
DURANT OK 35 57 50 70 / 0 0 30 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR OKZ018>020-
023>032-037>048-050>052.
TX...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR TXZ086-089-090.
&&
$$
25/84
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
416 PM CST TUE FEB 14 2012
.DISCUSSION...18Z GUIDANCE AND LATEST HRRR INDICATE LIGHT PRECIP
WILL BE POSSIBLE THIS EVENING AND WITH AREA OBS AND KCRP RADAR
INDICATING PRECIP ALREADY OCCURRING...HAVE ADDED MENTION OF PATCHY
DRIZZLE AND ISOLATED SHOWERS FOR THE EVENING HOURS. ALSO ADJUSTED
HOURLY TEMPERATURE AND HUMIDITY FORECAST FOR THIS EVENING DUE TO
TODAY/S MAX TEMPS BEING SIGNIFICANTLY LOWER THAN PREVIOUSLY
EXPECTED. UPDATED PRODUCTS TO BE SENT SHORTLY. NO CHANGES TO
FORECAST MADE BEYOND MIDNIGHT TONIGHT WITH THIS UPDATE.
&&
.PREV DISCUSSION... /ISSUED 304 PM CST TUE FEB 14 2012/
SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...LOW LEVEL JET WILL
INCREASE TO 30-35KTS TONIGHT WHICH WILL USHER DEEPER LOW LEVEL
MOISTURE INTO S TX. MOS GUIDANCE AND FCST SOUNDINGS ALL SHOW
FOG...POSSIBLY DENSE...TONIGHT/WED MORNING. HOWEVER...GIVEN THE
STRENGTHENING LOW LEVEL JET AND ELEVATED SFC WINDS...THERE IS SOME
UNCERTAINTY AS TO HOW LOW VISIBILITIES WILL DROP. HAVE INTRODUCED A
MENTION OF AREAS OF FOG BUT NO MENTION OF DENSE. PRECIP CHCS WILL BE
ON THE INCREASE BY WED MORNING AS AN UPPER LOW TRACKS TOWARD THE TX
PANHANDLE WITH EMBEDDED ENERGY/STRONG UPPER JET MOVING ACROSS TX. A
COLD FRONT IS PROGD TO MOVE INTO THE W CWA LATE MORNING OR EARLY
AFTERNOON...TRACKING E TO SE AND REACHING THE COAST LATE
AFTERNOON/EARLY EVENING. THE FRONTAL BDRY WILL PROVIDE LOW LEVEL
MOISTURE CONVERGENCE...ESPECIALLY ACROSS THE NE CWA. BEST CHC OF
SHRA`S/TSRA`S WILL BE ACROSS THE NE CWA DUE TO THE PROXIMITY OF THE
UPPER JET...HIGHEST CAPE...LOWEST CIN...DEEPEST MOISTURE. ALTHOUGH
THE UPPER JET WILL PROVIDE UPPER LEVEL SUPPORT FOR TSRA`S...THE JET
CORE/BEST ENERGY WILL BE MUCH FARTHER N...THEREFORE AM NOT EXPECTING
SEVERE TSRA`S AT THIS TIME. A FEW MAY BECOME STRONG ACROSS THE NE
CWA DUE TO A BRIEF WINDOW WHERE CAPE...HELICITY AND LIFT WILL BE IN
PLACE. HAVE SHOWN A TREND WITH THE POPS DECREASING ACROSS THE W AND
INCREASING ACROSS THE COASTAL WATERS AS THE UPPER SYSTEM MOVES E AND
THE FRONTAL BDRY MOVES OFFSHORE. DRIER AND COOLER CONDITIONS WILL
FILTER INTO S TX WED NIGHT BEHIND THE FRONT.
MARINE...PATCHY SEA FOG CAN BE EXPECTED TONIGHT AS DEWPOINTS
INCREASE ACROSS RELATIVELY COOLER WATER. THIS IS DUE TO INCREASING
SLY WINDS DVLPG TONIGHT TO MOD LEVELS...MAINLY ACROSS THE OFFSHORE
WATERS. WINDS WILL RELAX THROUGH WED AFTERNOON AS A COLD FRONT MOVES
INTO S TX. THE CHANCE FOR SHRA`S AND TSRA`S WILL INCREASE WED
AFTERNOON INTO EARLY WED EVENING AHD OF THE COLD FRONT WITH RAIN
CHCS DECREASING WED NIGHT AS THE COLD FRONT PUSHES S AND E OF THE
AREA. A WEAK TO MODERATE OFFSHORE FLOW CAN BE EXPECTED LATE WED
NIGHT/EARLY THU MORNING.
LONG TERM (THURSDAY THROUGH TUESDAY)...MAIN FORECAST CHALLENGE IS
DETERMINE RAIN CHANCES...IF AND WHEN. COLD FRONT IS COMING DOWN ON
THURSDAY...AND MODELS ARE DRYING OUT THE LOWER AND MID LEVELS.
THUS...THINK ANY QPF THAT MODELS ARE GENERATING ARE OVER-DONE.
HOWEVER...BETTER MID LEVEL MOISTURE DOES RETURN LATE THURSDAY NIGHT
SO WILL INCLUDE A SLIGHT CHANCE FOR LIGHT RAIN AFTER MIDNIGHT ON
THURSDAY NIGHT. ISENTROPIC UPGLIDE FRIDAY PROVIDES A CHANCE FOR SOME
LIGHT RAIN...THEN APPROACH OF UPPER TROUGH FRIDAY NIGHT PROVIDES A
GOOD CHANCE FOR RAIN AND POSSIBLE ELEVATED THUNDERSTORMS INTO
SATURDAY MORNING. GFS IS NOW A BIT FASTER THAN ECMWF.. UKMET...AND
CANADIAN. THE GFS TIMING/MOVEMENT WOULD MEAN LOWER POPS WEST
SATURDAY MORNING. DUE TO SLIGHT MODEL CHANGES FROM RUN TO
RUN...GENERALLY HAVE KEPT SIMILAR POPS IN FOR SATURDAY MORNING OUT
EAST AS HAVE ON FRIDAY LATE NIGHT...BUT DECREASED THEM A BIT TO THE
WEST FROM FRIDAY NIGHTS POPS. FRONT COMES DOWN ON SATURDAY AS
SURFACE LOW/COASTAL TROUGH MOVES EAST...WITH DRY CONDITIONS EXPECTED
FOR THE REMAINDER OF THE FORECAST. SINCE RETURN FLOW RESUMES BY
MONDAY...COULD NOT RULE OUT SOME CONVECTION LATE MONDAY
NIGHT/TUESDAY AS NEXT SYSTEM APPROACHES FROM WEST. HOWEVER...THE
IMPACTS FROM THIS SYSTEM IMPACTS MAY BE A BIT TOO FAR NORTH FOR ANY
NOTABLE RAIN CHANCES SO LEFT OFF (MODELS HAVE BEEN FLIP-FLOPPING ON
THAT TOO). SUMMARY FOR TEMPERATURES...GENERALLY ON THE COOL SIDE
THURSDAY AND ESPECIALLY FRIDAY (ISENTROPIC LIFT/RAIN-COOLED
AIR)...CONTINUES ON SATURDAY BEHIND FRONT. GRADUAL WARM UP BY EARLY
NEXT WEEK WITH THE RETURN FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 65 80 57 69 53 / 20 30 10 10 20
VICTORIA 64 77 53 66 48 / 20 50 20 10 10
LAREDO 62 85 57 71 53 / 10 10 10 10 20
ALICE 65 81 55 69 51 / 20 30 10 10 20
ROCKPORT 65 77 57 66 50 / 20 40 20 10 20
COTULLA 60 80 52 68 48 / 10 20 10 10 10
KINGSVILLE 65 81 57 69 50 / 20 20 10 10 20
NAVY CORPUS 66 76 58 68 55 / 20 30 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1133 AM CST TUE FEB 14 2012
.SHORT TERM...TODAY THROUGH THURSDAY
353 AM CST TUE FEB 14 2012
AT 3 AM...KARX RADAR SHOWED A DEFORMATION BAND OF LIGHT SNOW MOVING
EAST ACROSS THE FORECAST AREA. THE WESTERN EDGE WAS LOCATED FROM
MONDOVI WISCONSIN TO CHARLES CITY IOWA. THE LATEST RUC SHOWS THAT
THE 800-700 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL
CONTINUE TO MOVE EAST THIS MORNING AND GRADUALLY WEAKEN. AT THE
SAME TIME...THE SOUNDINGS SHOW THAT THE MOISTURE BELOW 850 MB
WILL GRADUALLY DRY. EVEN THOUGH IT IS DRYING OUT...THERE
CONTINUES TO BE SOME ICE CRYSTALS SEEDING FROM ALOFT TO KEEP THE
PRECIPITATION IN THE FORM OF SNOW. DUE TO THIS JUST WENT WITH SOME
FLURRIES THIS MORNING.
FOR TONIGHT...THE 14.00Z MODELS SUGGEST THAT A PV ANOMALY WILL
MOVE EAST THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN. MODEL
SOUNDINGS SHOW SOME MOISTURE BETWEEN 925 AND 700 MB. IN THIS SAME
LAYER...THERE IS ENOUGH LIFT FOR A BRIEF PERIOD OF LIGHT SNOW ACROSS
NORTH CENTRAL WISCONSIN. THE NAM/WRF...GFS...AND GEM GENERATE SOME
LIGHT PRECIPITATION ACROSS THIS AREA. DUE TO THIS...ADDED A SLIGHT
CHANCE TO THE FORECAST FOR TONIGHT.
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY...THE 14.00Z GFS...ECMWF...
AND NAM/WRF ARE IN GOOD AGREEMENT THAT A SURFACE LOW WILL TRACK
FROM SOUTHWEST MISSOURI NORTHEAST TO SOUTHERN ONTARIO. THIS TRACK
IS VERY SIMILAR TO THE 13.12Z MODELS. THE ONE EXCEPTION TO THIS
WAS THE GEM WHICH SHOWS THE LOW MOVING FROM KANSAS CITY NORTHEAST
TO CHICAGO ILLINOIS. LOOKING AT ITS ENSEMBLE FAMILY...ONLY 3 OF
ITS 16 MEMBERS SUPPORT THIS MORE NORTHERN TRACK...AND IN MANY
CASES THERE IS NO PRECIPITATION AT ALL IN OUR FORECAST AREA. THE
REASON FOR THE MORE SOUTHERN TRACK THAN THE 13.00Z IS HOW THE
NORTHERN STREAM SYSTEM MOVING THROUGH SOUTHERN CANADA INTERACTS WITH
THE SOUTHERN STREAM SYSTEM MOVING THROUGH THE CENTRAL PLAINS AND MID
MISSISSIPPI RIVER VALLEY. THE NORTHERN STREAM IS SYSTEM LESS
AMPLIFIED IN ITS LATEST RUNS /WITH THE EXCEPTION OF THE GEM/...AND
THIS RESULT IN THE SOUTHERN LOW NOT BEING DRAWN NORTHWARD INTO OUR
AREA. DUE TO THIS...TRENDED BOTH WEDNESDAY AFTERNOON AND THURSDAY
DRIER. IF THIS TREND CONTINUES...WILL LIKELY HAVE TO GO DRY FOR BOTH
OF THESE PERIOD. FOR WEDNESDAY NIGHT...THE PRECIPITATION CHANCES
WERE TRENDED FURTHER SOUTHEAST. AT THIS TIME...IT LOOKS LIKE THE
ONLY MEASURABLE SNOW WILL BE ACROSS SOUTHWEST WISCONSIN.
.LONG TERM...THURSDAY NIGHT THROUGH WASHINGTONS BIRTHDAY
342 AM CST TUE FEB 14 2012
ON WASHINGTONS BIRTHDAY...THE 14.00Z CONTINUES TO SHOW THAT
CYCLOGENESIS WILL DEVELOP ACROSS THE DAKOTAS AND THEN MOVE EAST
THROUGH THE FORECAST AREA. LIKE THE PAST COUPLE OF DAYS...THE
PRECIPITATION TYPE FORECAST IS GREATLY COMPLICATED BY DIFFERENCES
IN THE BOUNDARY LAYER TEMPERATURES. FOR THE TIME BEING...JUST WENT
WITH A MENTION OF RAIN AND SNOW WITH THIS SYSTEM.
&&
.AVIATION...THIS AFTERNOON THROUGH WEDNESDAY
1133 AM CST TUE FEB 14 2012
CONFIDENCE ON THE LOW SIDE...AS DETAILS OF MOISTURE/STRATUS TRAPPED
UNDER A SHALLOW BUT STRONG INVERSION THIS TIME OF YEAR INHERENTLY
DIFFICULT. IFR TO MVFR STRATUS OVER THE TAF SITES PROBLEMATIC THRU
THIS AFTERNOON/INTO THIS EVENING AS PLENTIFUL MOISTURE REMAINS
TRAPPED UNDER AN INVERSION NEAR 900MB. SFC OBS/SATELLITE IMAGERY
INDICATE SLOW CLEARING FROM THE WEST THRU THIS MORNING AND DID TREND
KRST TOWARD A BREAKUP OF THE STRATUS DECK DURING THE MID AFTERNOON.
BREAKUP OF THE MVFR STRATUS NOT LIKELY TO REACH KLSE UNTIL AT LEAST
THIS EVENING. NEXT SHORTWAVE WILL SPREAD SOME BKN080-100 CLOUDS
ACROSS THE TAF SITES THRU THIS EVENING...WITH THESE CLOUDS BECOMING
SCT FOR THE LATE EVENING/OVERNIGHT ONCE THE WAVE PASSES. YET ANOTHER
SHORTWAVE WILL SPREAD ANOTHER ROUND OF MAINLY BKN070-100 CLOUDS
ACROSS THE TAF SITES FOR WED. FOR VSBYS...THE STRONG INVERSION NEAR
900MB WILL REMAIN IN PLACE THRU TONIGHT/WED AND LOWER A BIT TOWARD
925- 950MB. THIS WILL CONTINUE TO TRAP ABUNDANT BOUNDARY LAYER
MOISTURE OVER THE AREA. VSBYS WILL CONTINUE TO IMPROVE THIS
AFTERNOON...BUT WITH LIGHT SOUTHWEST/SOUTH WINDS TONIGHT/EARLY WED
AND A DECREASE OF CLOUDS TONIGHT...MVFR VSBYS WITH LCL IFR VSBYS IN
BR EXPECTED TO PREVAIL LATER THIS EVENING THRU AT LEAST MID MORNING
WED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE FEB 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
536 AM CST TUE FEB 14 2012
.SHORT TERM...TODAY THROUGH THURSDAY
353 AM CST TUE FEB 14 2012
AT 3 AM...KARX RADAR SHOWED A DEFORMATION BAND OF LIGHT SNOW MOVING
EAST ACROSS THE FORECAST AREA. THE WESTERN EDGE WAS LOCATED FROM
MONDOVI WISCONSIN TO CHARLES CITY IOWA. THE LATEST RUC SHOWS THAT
THE 800-700 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL
CONTINUE TO MOVE EAST THIS MORNING AND GRADUALLY WEAKEN. AT THE
SAME TIME...THE SOUNDINGS SHOW THAT THE MOISTURE BELOW 850 MB
WILL GRADUALLY DRY. EVEN THOUGH IT IS DRYING OUT...THERE
CONTINUES TO BE SOME ICE CRYSTALS SEEDING FROM ALOFT TO KEEP THE
PRECIPITATION IN THE FORM OF SNOW. DUE TO THIS JUST WENT WITH SOME
FLURRIES THIS MORNING.
FOR TONIGHT...THE 14.00Z MODELS SUGGEST THAT A PV ANOMALY WILL
MOVE EAST THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN. MODEL
SOUNDINGS SHOW SOME MOISTURE BETWEEN 925 AND 700 MB. IN THIS SAME
LAYER...THERE IS ENOUGH LIFT FOR A BRIEF PERIOD OF LIGHT SNOW ACROSS
NORTH CENTRAL WISCONSIN. THE NAM/WRF...GFS...AND GEM GENERATE SOME
LIGHT PRECIPITATION ACROSS THIS AREA. DUE TO THIS...ADDED A SLIGHT
CHANCE TO THE FORECAST FOR TONIGHT.
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY...THE 14.00Z GFS...ECMWF...
AND NAM/WRF ARE IN GOOD AGREEMENT THAT A SURFACE LOW WILL TRACK
FROM SOUTHWEST MISSOURI NORTHEAST TO SOUTHERN ONTARIO. THIS TRACK
IS VERY SIMILAR TO THE 13.12Z MODELS. THE ONE EXCEPTION TO THIS
WAS THE GEM WHICH SHOWS THE LOW MOVING FROM KANSAS CITY NORTHEAST
TO CHICAGO ILLINOIS. LOOKING AT ITS ENSEMBLE FAMILY...ONLY 3 OF
ITS 16 MEMBERS SUPPORT THIS MORE NORTHERN TRACK...AND IN MANY
CASES THERE IS NO PRECIPITATION AT ALL IN OUR FORECAST AREA. THE
REASON FOR THE MORE SOUTHERN TRACK THAN THE 13.00Z IS HOW THE
NORTHERN STREAM SYSTEM MOVING THROUGH SOUTHERN CANADA INTERACTS WITH
THE SOUTHERN STREAM SYSTEM MOVING THROUGH THE CENTRAL PLAINS AND MID
MISSISSIPPI RIVER VALLEY. THE NORTHERN STREAM IS SYSTEM LESS
AMPLIFIED IN ITS LATEST RUNS /WITH THE EXCEPTION OF THE GEM/...AND
THIS RESULT IN THE SOUTHERN LOW NOT BEING DRAWN NORTHWARD INTO OUR
AREA. DUE TO THIS...TRENDED BOTH WEDNESDAY AFTERNOON AND THURSDAY
DRIER. IF THIS TREND CONTINUES...WILL LIKELY HAVE TO GO DRY FOR BOTH
OF THESE PERIOD. FOR WEDNESDAY NIGHT...THE PRECIPITATION CHANCES
WERE TRENDED FURTHER SOUTHEAST. AT THIS TIME...IT LOOKS LIKE THE
ONLY MEASURABLE SNOW WILL BE ACROSS SOUTHWEST WISCONSIN.
.LONG TERM...THURSDAY NIGHT THROUGH WASHINGTONS BIRTHDAY
342 AM CST TUE FEB 14 2012
ON WASHINGTONS BIRTHDAY...THE 14.00Z CONTINUES TO SHOW THAT
CYCLOGENESIS WILL DEVELOP ACROSS THE DAKOTAS AND THEN MOVE EAST
THROUGH THE FORECAST AREA. LIKE THE PAST COUPLE OF DAYS...THE
PRECIPITATION TYPE FORECAST IS GREATLY COMPLICATED BY DIFFERENCES
IN THE BOUNDARY LAYER TEMPERATURES. FOR THE TIME BEING...JUST WENT
WITH A MENTION OF RAIN AND SNOW WITH THIS SYSTEM.
&&
.AVIATION...TODAY AND TONIGHT
536 AM CST TUE FEB 14 2012
IFR TO MVFR STRATUS OVER THE TAF SITES HAS THE POTENTIAL TO LOWER
SLIGHTLY DURING THE NEXT FEW HOURS...TO LIFR AT KRST AND IFR AT
KLSE. THIS LOWERING IS IN RESPONSE TO MID LEVEL CLOUDS ASSOCIATED
WITH -SN MOVING EAST AWAY FROM THE TAF SITES. SOME SITES ACROSS
SOUTH CENTRAL MINNESOTA ARE ALREADY LIFR. THE STRATUS SHOULD THEN
BEGIN TO BREAK UP EARLY IN THE AFTERNOON...DUE TO A COMBINATION OF
DAYTIME HEATING AND AN AREA OF VFR STRATUS OVER DAKOTAS SPREADING
EAST INTO THE TAF SITES. MVFR VISIBILITIES ARE ALSO ANTICIPATED TO
CLIMB TO VFR BY NOON THANKS TO DAYTIME HEATING. BIG CONCERN
TONIGHT IS MONITORING THE CURRENT LIFR/VLIFR STRATUS AND FOG IN
SOUTHERN IOWA AND NORTHERN MISSOURI. IF THIS DOES NOT DISSIPATE
TODAY...THE SOUTHERLY WINDS TONIGHT COULD ADVECT IT BACK NORTH
INTO THE TAF SITES UNDERNEATH THE HIGHER STRATUS ALOFT. IN
ADDITION...VISIBILITIES COULD DROP TO MVFR OR LOWER. BECAUSE
CONFIDENCE IN THIS SCENARIO IS LOW...FOR NOW HAVE CONTINUED WITH
THE PREVIOUS FORECAST IDEA OF MAINTAINING VFR CEILINGS
TONIGHT. HOWEVER...DID INCLUDE AN MVFR VISIBILITY AT KRST TO
ACCOUNT FOR LINGERING LOW LEVEL MOISTURE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE FEB 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION...CORRECTED WED AFTERNOON THROUGH THURSDAY
NWS LA CROSSE WI
353 AM CST TUE FEB 14 2012
.SHORT TERM...TODAY THROUGH THURSDAY
353 AM CST TUE FEB 14 2012
AT 3 AM...KARX RADAR SHOWED A DEFORMATION BAND OF LIGHT SNOW MOVING
EAST ACROSS THE FORECAST AREA. THE WESTERN EDGE WAS LOCATED FROM
MONDOVI WISCONSIN TO CHARLES CITY IOWA. THE LATEST RUC SHOWS THAT
THE 800-700 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL
CONTINUE TO MOVE EAST THIS MORNING AND GRADUALLY WEAKEN. AT THE
SAME TIME...THE SOUNDINGS SHOW THAT THE MOISTURE BELOW 850 MB
WILL GRADUALLY DRY. EVEN THOUGH IT IS DRYING OUT...THERE
CONTINUES TO BE SOME ICE CRYSTALS SEEDING FROM ALOFT TO KEEP THE
PRECIPITATION IN THE FORM OF SNOW. DUE TO THIS JUST WENT WITH SOME
FLURRIES THIS MORNING.
FOR TONIGHT...THE 14.00Z MODELS SUGGEST THAT A PV ANOMALY WILL
MOVE EAST THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN. MODEL
SOUNDINGS SHOW SOME MOISTURE BETWEEN 925 AND 700 MB. IN THIS SAME
LAYER...THERE IS ENOUGH LIFT FOR A BRIEF PERIOD OF LIGHT SNOW ACROSS
NORTH CENTRAL WISCONSIN. THE NAM/WRF...GFS...AND GEM GENERATE SOME
LIGHT PRECIPITATION ACROSS THIS AREA. DUE TO THIS...ADDED A SLIGHT
CHANCE TO THE FORECAST FOR TONIGHT.
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY...THE 14.00Z GFS...ECMWF...
AND NAM/WRF ARE IN GOOD AGREEMENT THAT A SURFACE LOW WILL TRACK
FROM SOUTHWEST MISSOURI NORTHEAST TO SOUTHERN ONTARIO. THIS TRACK
IS VERY SIMILAR TO THE 13.12Z MODELS. THE ONE EXCEPTION TO THIS
WAS THE GEM WHICH SHOWS THE LOW MOVING FROM KANSAS CITY NORTHEAST
TO CHICAGO ILLINOIS. LOOKING AT ITS ENSEMBLE FAMILY...ONLY 3 OF
ITS 16 MEMBERS SUPPORT THIS MORE NORTHERN TRACK...AND IN MANY
CASES THERE IS NO PRECIPITATION AT ALL IN OUR FORECAST AREA. THE
REASON FOR THE MORE SOUTHERN TRACK THAN THE 13.00Z IS HOW THE
NORTHERN STREAM SYSTEM MOVING THROUGH SOUTHERN CANADA INTERACTS WITH
THE SOUTHERN STREAM SYSTEM MOVING THROUGH THE CENTRAL PLAINS AND MID
MISSISSIPPI RIVER VALLEY. THE NORTHERN STREAM IS SYSTEM LESS
AMPLIFIED IN ITS LATEST RUNS /WITH THE EXCEPTION OF THE GEM/...AND
THIS RESULT IN THE SOUTHERN LOW NOT BEING DRAWN NORTHWARD INTO OUR
AREA. DUE TO THIS...TRENDED BOTH WEDNESDAY AFTERNOON AND THURSDAY
DRIER. IF THIS TREND CONTINUES...WILL LIKELY HAVE TO GO DRY FOR BOTH
OF THESE PERIOD. FOR WEDNESDAY NIGHT...THE PRECIPITATION CHANCES
WERE TRENDED FURTHER SOUTHEAST. AT THIS TIME...IT LOOKS LIKE THE
ONLY MEASURABLE SNOW WILL BE ACROSS SOUTHWEST WISCONSIN.
.LONG TERM...THURSDAY NIGHT THROUGH WASHINGTONS BIRTHDAY
342 AM CST TUE FEB 14 2012
ON WASHINGTONS BIRTHDAY...THE 14.00Z CONTINUES TO SHOW THAT
CYCLOGENESIS WILL DEVELOP ACROSS THE DAKOTAS AND THEN MOVE EAST
THROUGH THE FORECAST AREA. LIKE THE PAST COUPLE OF DAYS...THE
PRECIPITATION TYPE FORECAST IS GREATLY COMPLICATED BY DIFFERENCES
IN THE BOUNDARY LAYER TEMPERATURES. FOR THE TIME BEING...JUST WENT
WITH A MENTION OF RAIN AND SNOW WITH THIS SYSTEM.
&&
.AVIATION...
1105 PM CST MON FEB 13 2012
IFR/MVFR CIGS WILL CONTINUE THROUGH THE EARLY MORNING...LOOKING FOR
IMPROVEMENT FROM WEST TO EAST IN THE AFTERNOON. HOW QUICKLY THE CIGS
RISE IS IN QUESTION THOUGH...WITH DIFFERING OPINIONS IN THE MODELS.
CONFIDENCE NOT HIGH...BUT FAIRLY SURE THEY SHOULD HANG THROUGH
18Z...AND WILL TREND CIGS THIS WAY. -SN LOOKS LIKE THE MAIN THREAT
OVERNIGHT...AND WILL REDUCE VSBYS TO 2-3 SM AT TIMES. DON/T EXPECT
MUCH MORE ACCUMULATION...PERHAPS A COUPLE TENTHS OF AN INCH.
ONE POTENTIAL TROUBLE SPOT IS THE POSSIBILITY OF SUB 1SM FG VSBYS AT
KRST AFTER 12Z OR SO. SFC OBS AND SATELLITE TRENDS POINT TO LOW CIGS
AND QUITE A FEW 1/4SM LOCATIONS ON THE FAR WESTERN EDGE OF THE
CLOUDS SHIELD. THIS COULD TRACK ACROSS KRST...BUT SHOULD MODERATE
ENOUGH THAT ANY IMPACT ON KLSE WOULD BE MINIMAL. AGAIN...UNCERTAIN
WITH JUST HOW LOW CIGS/VSBYS WILL BE BY THE TIME THIS REGION GETS TO
KRST. WILL OPT TO KEEP A PERIOD OF 1SM BR FOR KRST FOR NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE FEB 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 AM CST TUE FEB 14 2012
.SHORT TERM...TODAY THROUGH THURSDAY
342 AM CST TUE FEB 14 2012
AT 3 AM...KARX RADAR SHOWED A DEFORMATION BAND OF LIGHT SNOW MOVING
EAST ACROSS THE FORECAST AREA. THE WESTERN EDGE WAS LOCATED FROM
MONDOVI WISCONSIN TO CHARLES CITY IOWA. THE LATEST RUC SHOWS THAT
THE 800-700 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL
CONTINUE TO MOVE EAST THIS MORNING AND GRADUALLY WEAKEN. AT THE
SAME TIME...THE SOUNDINGS SHOW THAT THE MOISTURE BELOW 850 MB
WILL GRADUALLY DRY. EVEN THOUGH IT IS DRYING OUT...THERE
CONTINUES TO BE SOME ICE CRYSTALS SEEDING FROM ALOFT TO KEEP THE
PRECIPITATION IN THE FORM OF SNOW. DUE TO THIS JUST WENT WITH SOME
FLURRIES THIS MORNING.
FOR TONIGHT...THE 14.00Z MODELS SUGGEST THAT A PV ANOMALY WILL
MOVE EAST THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN. MODEL
SOUNDINGS SHOW SOME MOISTURE BETWEEN 925 AND 700 MB. IN THIS SAME
LAYER...THERE IS ENOUGH LIFT FOR A BRIEF PERIOD OF LIGHT SNOW ACROSS
NORTH CENTRAL WISCONSIN. THE NAM/WRF...GFS...AND GEM GENERATE SOME
LIGHT PRECIPITATION ACROSS THIS AREA. DUE TO THIS...ADDED A SLIGHT
CHANCE TO THE FORECAST FOR TONIGHT.
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY...THE 14.00Z GFS...ECMWF...
AND NAM/WRF ARE IN GOOD AGREEMENT THAT A SURFACE LOW WILL TRACK
FROM SOUTHWEST MISSOURI NORTHEAST TO SOUTHERN ONTARIO. THIS TRACK
IS VERY SIMILAR TO THE 13.12Z MODELS. THE ONE EXCEPTION TO THIS
WAS THE GEM WHICH SHOWS THE LOW MOVING FROM KANSAS CITY NORTHEAST
TO CHICAGO ILLINOIS. LOOKING AT ITS ENSEMBLE FAMILY...ONLY 3 OF
ITS 16 MEMBERS SUPPORT THIS MORE NORTHERN TRACK...AND IN MANY
CASES THERE IS NO PRECIPITATION AT ALL IN OUR FORECAST AREA. THE
REASON FOR THE MORE SOUTHERN TRACK THAN THE 13.00Z IS HOW THE
NORTHERN STREAM SYSTEM MOVING THROUGH SOUTHERN CANADA INTERACTS
WITH THE SOUTHERN STREAM MOVING THROUGH THE CENTRAL PLAINS AND
MID MISSISSIPPI RIVER VALLEY. THE NORTHERN STREAM SYSTEM IS
MOVING A BIT FASTER EAST THAT ITS SOUTHERN COUNTERPART. AS A
RESULT...IT IS NOT DRAWN NORTHWARD INTO OUR AREA. DUE TO
THIS...TRENDED BOTH WEDNESDAY AFTERNOON AND THURSDAY DRIER. IF
THIS TREND CONTINUES...WILL LIKELY HAVE TO GO DRY FOR BOTH OF
THESE PERIOD. FOR WEDNESDAY NIGHT...THE PRECIPITATION CHANCES WERE
TRENDED FURTHER SOUTHEAST. AT THIS TIME...IT LOOKS LIKE THE ONLY
MEASURABLE SNOW WILL BE ACROSS SOUTHWEST WISCONSIN.
.LONG TERM...THURSDAY NIGHT THROUGH WASHINGTONS BIRTHDAY
342 AM CST TUE FEB 14 2012
ON WASHINGTONS BIRTHDAY...THE 14.00Z CONTINUES TO SHOW THAT
CYCLOGENESIS WILL DEVELOP ACROSS THE DAKOTAS AND THEN MOVE EAST
THROUGH THE FORECAST AREA. LIKE THE PAST COUPLE OF DAYS...THE
PRECIPITATION TYPE FORECAST IS GREATLY COMPLICATED BY DIFFERENCES
IN THE BOUNDARY LAYER TEMPERATURES. FOR THE TIME BEING...JUST WENT
WITH A MENTION OF RAIN AND SNOW WITH THIS SYSTEM.
&&
.AVIATION...
1105 PM CST MON FEB 13 2012
IFR/MVFR CIGS WILL CONTINUE THROUGH THE EARLY MORNING...LOOKING FOR
IMPROVEMENT FROM WEST TO EAST IN THE AFTERNOON. HOW QUICKLY THE CIGS
RISE IS IN QUESTION THOUGH...WITH DIFFERING OPINIONS IN THE MODELS.
CONFIDENCE NOT HIGH...BUT FAIRLY SURE THEY SHOULD HANG THROUGH
18Z...AND WILL TREND CIGS THIS WAY. -SN LOOKS LIKE THE MAIN THREAT
OVERNIGHT...AND WILL REDUCE VSBYS TO 2-3 SM AT TIMES. DON/T EXPECT
MUCH MORE ACCUMULATION...PERHAPS A COUPLE TENTHS OF AN INCH.
ONE POTENTIAL TROUBLE SPOT IS THE POSSIBILITY OF SUB 1SM FG VSBYS AT
KRST AFTER 12Z OR SO. SFC OBS AND SATELLITE TRENDS POINT TO LOW CIGS
AND QUITE A FEW 1/4SM LOCATIONS ON THE FAR WESTERN EDGE OF THE
CLOUDS SHIELD. THIS COULD TRACK ACROSS KRST...BUT SHOULD MODERATE
ENOUGH THAT ANY IMPACT ON KLSE WOULD BE MINIMAL. AGAIN...UNCERTAIN
WITH JUST HOW LOW CIGS/VSBYS WILL BE BY THE TIME THIS REGION GETS TO
KRST. WILL OPT TO KEEP A PERIOD OF 1SM BR FOR KRST FOR NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE FEB 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
227 AM CST THU FEB 16 2012
.DISCUSSION...
823 PM CST
THERE WERE SOME SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST BUT
THE GENERAL THEME OF A WET NIGHT WITH TEMPERATURES DROPPING AT A
SNAILS PACE STILL LOOKS GOOD.
AFTER SOME DRIER AIR ALOFT AND LIMITED FOCUS...RAIN HAS SPREAD
OVER A LARGE PORTION OF THE AREA THIS EVENING. THIS APPEARS TO BE
THANKS IN PART TO A LEAD SHORT WAVE PER WV/PROFILER ANALYSIS AND
ASSOCIATED BETTER 850-700MB CONVERGENCE THAT LINES UP WELL WITH
RADAR RETURNS. GIVEN THE RUC ANALYSIS OF THIS FIELD...TRENDS ON
RADAR...AND HIGH AVAILABLE MOISTURE /BASICALLY 200 PERCENT OF
NORMAL PWATS ON DVN AND ILX RAOBS/...THE RAIN AXIS SHOULD
CONTINUE FOR SEVERAL HOURS WHILE GRADUALLY EXPANDING/EVOLVING
SOUTHEAST AS FORCING FROM THE MAIN UPPER LOW APPROACHES. THIS WAVE
STILL HAS A CLOSED CIRCULATION ON WATER VAPOR AND IS TRIGGERING
CONVECTION ACROSS WESTERN MO. BUT THIS IS FORECAST TO DAMPEN IN
THE MORE CONFLUENT FLOW...LIMITING MORE INTENSE FORCING AND
DYNAMIC COOLING EFFECTS. SO WITH MORE LIMITED FORCING HAVE ADDED
DRIZZLE AND FOG MENTION IN THE FORECAST...ESPECIALLY OVERNIGHT.
THE LOW T/TD SPREADS AND DECREASING FLOW WITH THE BAGGY SURFACE
TROUGH MOVING ACROSS SHOULD FURTHER AID IN SOME AREAS OF LIGHT
FOG.
IT STILL IS POSSIBLE TO HAVE SOME WET NON-ACCUMULATING SNOW
TOWARDS THE NORTHWEST FORECAST AREA LATE TONIGHT AND MAYBE A BRIEF
MIX TOWARDS CHICAGO AS THE SYSTEM DEPARTS THU MORNING. WHILE THE
DVN RAOB DID COME IN AROUND 1-2C COOLER IN THE LOWER PROFILE THAN
THE 00Z RUC AND 18Z NAM...IT STILL DEPICTED NEARLY A 4500 FT THICK
LAYER NEAR OR ABOVE FREEZING. IN THE ABSENCE OF STRONG COLD AIR
ADVECTION...A DECREASING CHANCE FOR SNOW IN THE FORECAST
CONTINUES. AS FOR THUNDER...SOME WEAK POSITIVE INSTABILITY IS
PRESENT ON THE ILX SOUNDING WHEN LIFTING PARCELS FROM 850 MB...BUT
THE BETTER ELEVATED INSTABILITY GRADIENT WHICH LINES UP WITH
ONGOING CONVECTION IN MO LOOKS TO STAY TO OUR SOUTH. POCKETS OF
ISOLATED HEAVIER RAIN HAVE BEEN SEEN PER DUAL-POL ANALYSIS. GOING
QPF FORECAST LOOKS ALRIGHT ON MAGNITUDE...BUT DID SHRINK THE AREAL
COVERAGE OF THE FORECAST ONE QUARTER OF AN INCH AND GREATER.
MTF
//PREV DISCUSSION...
317 PM...PRIMARY FORECAST FOCUS REMAINS APPROACHING SYSTEM WITH
MAINLY RAIN/SHOWERS TONIGHT.
AFTER A BRIEF PERIOD OF SOME SUN THIS MORNING...LOW CLOUDS SPREAD
NORTH AND DEVELOPED ACROSS THE AREA ALONG WITH SOME SHOWERS MIDDAY
WHICH HAVE SINCE MOVED OVER THE LAKE. FAIRLY STRONG UPPER WAVE TO
MOVE ACROSS THE AREA TONIGHT...THOUGH IT SLOWLY WEAKENS WITH TIME.
SCATTERED SHOWERS CURRENTLY DEVELOPING FROM KANSAS INTO SOUTHERN
IOWA AND THIS ACTIVITY WILL CONTINUE NORTHEAST ACROSS THE AREA
THIS EVENING INTO EARLY THURSDAY MORNING. LATEST GUIDANCE
SUGGESTS A TREND OF THE HEAVIEST RAIN...OR THE POTENTIAL FOR THE
HEAVIEST RAIN...FALLING ACROSS THE SOUTHERN CWA AND POINTS SOUTH
AND EAST. SO HAVE BACKED OFF ON QPF AMOUNTS SOME ESPECIALLY NORTH
WITH STRONGER CONVECTION FURTHER SOUTH TAKING SOME OF THE
AVAILABLE MOISTURE/QPF. THOUGH SINCE THERE COULD STILL BE SOME
CONVECTIVE ELEMENTS...LOCALIZED RAINFALL TOTALS OF A HALF TO THREE
QUARTERS OF AN INCH ARE STILL POSSIBLE. THERE IS ALSO SOME SMALL
INSTABILITY ALOFT THAT MAY CAUSE A RUMBLE OR TWO OF THUNDER...
MAINLY ACROSS THE FAR SOUTHERN CWA AND WILL CONTINUE WITH NO
MENTION OF THUNDER.
AS FOR ANY SNOW POTENTIAL...NOT MUCH COLD AIR TO WORK WITH THIS
SYSTEM AND DEW POINTS ALREADY CREEPING UP INTO THE MID 30S ACROSS
NORTHERN IL. ANY SNOW WOULD LIKELY RESULT FROM PRECIP COOLING THE
COLUMN ON THE BACK SIDE OF THE PRECIP LATE TONIGHT INTO EARLY
THURSDAY MORNING...RATHER THAN SHARP COLD AIR ADVECTION. AND BY
THE TIME THERE IS ENOUGH COLD AIR FOR PRECIP TO CHANGEOVER TO
SNOW...IT APPEARS PRECIP WILL BE ENDING. THUS HAVE MAINTAINED A
CHANCE OF SNOW ACROSS THE FAR NORTHWEST CWA OVERNIGHT AND THEN A
CHANCE OF RAIN OR SNOW SHOWERS MIXED THURSDAY MORNING...BUT EVEN
IF PRECIP WERE TO GO OVER TO SNOW...GROUND WOULD LIKELY BE WARM
ENOUGH AND WET ENOUGH THAT LITTLE OR NO ACCUMULATION WOULD RESULT.
AND AS NOTED...HUNG ONTO SLIGHT/CHANCE POPS THURSDAY MORNING BUT
ITS ALSO POSSIBLE THAT PRECIP MAY END BY SUNRISE MOST AREAS. IN
ADDITION...IF HEAVIER RAIN/SHOWERS DO END UP FURTHER SOUTH...
PRECIP MIGHT END UP BEING MORE DRIZZLE.
TEMPERATURES CURRENTLY IN THE LOWER 40S WILL SLOWLY FALL INTO THE
MID/UPPER 30S BUT FOR THE MOST PART WILL BE STEADY...PROBABLY NOT
DROPPING SIGNIFICANTLY UNTIL WIDESPREAD PRECIP BEGINS FALLING.
LOWS ACROSS THE NORTHWEST MAY DIP DOWN TO FREEZING BY MORNING BUT
MOST OF THE CWA LIKELY TO STAY JUST ABOVE FREEZING THROUGH
MORNING. CLOUDS BEGIN CLEARING BY LATE THURSDAY MORNING AND WITH
SOME SUN IN THE AFTERNOON...SHOULD SEE TEMPS WARM INTO THE LOWER
40S THURSDAY.
A RIDGE OF HIGH PRESSURE SLIDES BY THURSDAY NIGHT INTO FRIDAY WITH
SOUTHERLY FLOW RETURNING FRIDAY AFTERNOON. DEPENDING ON THE EXTENT
OF INCREASING CLOUDS FRIDAY AFTERNOON...TEMPS WARMING BACK INTO
THE MID/UPPER 40S SEEMS REASONABLE FROM THIS DISTANCE. MODELS THEN
BRING ACROSS ANOTHER WEAK SURFACE LOW FRIDAY NIGHT. APPEARS THE
BULK OF THE PRECIP WITH THIS SYSTEM WILL REMAIN ON THE NORTH SIDE
OF THIS LOW AND NORTH OF THE CWA...BUT A FEW RAIN OR SNOW SHOWERS
APPEAR POSSIBLE ALONG THE TRAILING COLD FRONT LATE FRIDAY NIGHT
INTO SATURDAY MORNING AND INTRODUCED LOW CHANCE POPS DURING THIS
TIME PERIOD. THIS COLD FRONT USHERS IN SOME COLDER AIR...THOUGH
THE MODELS DIFFER ON THE EXTENT OF JUST HOW COLD THIS AIR WILL
BE. DOESN/T APPEAR TOO COLD BUT HIGHS THIS WEEKEND LIKELY ONLY IN
THE 30S.
NEXT WEEK LOOKING BOTH UNSETTLED AND UNCERTAIN AS A POSSIBLE COLD
FRONT MOVES THROUGH THE AREA TUESDAY WITH A STRONGER SYSTEM
LIFTING NORTHEAST ACROSS THE OHIO VALLEY/SOUTHERN LAKES REGION
TOWARD MIDWEEK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* IFR/LIFR CIGS TONIGHT... IMPROVING AFTER MID-MORNING.
* IFR VSBY WITH HEAVIER SHRA...MVFR VSBY OTHERWISE OVERNIGHT.
* MAY SEE IFR FOG DEVELOP BEHIND RA.
* GUSTY NW WIND DEVELOPING THU.
JEE
//DISCUSSION...UPDATED 06Z...
SYSTEM MOVING OVER THE MIDWEST IS RATHER DISORGANIZED BASED ON
CLOUD TOP TEMPS SEEN IR SATELLITE AND ON RADAR LOOPS. EVEN THOUGH
A WELL DEFINED UPPER LOW IS STILL SEEN OVER SW MO THERE APPEARS
TO BE MULTIPLE SMALLER SCALE IMPULSES EMBEDDED WITHIN THE OVERALL
LARGE SCALE FLOW.
MID LEVEL TROUGH IS CURRENTLY MOVING OVER SOUTHERN WI AND
NORTHERN IL. TROUGH AXIS AND TRAILING EDGE OF RAIN CURRENTLY OVER
THE AREA EXPECTED TO BE E OF CHI VICINITY BY 07Z BASED ON LATEST
MODEL PROGS AND EXTRAPOLATION OF RECENT RADAR IMAGES.
HOWEVER...ANOTHER AREA OF RAIN CURRENTLY OVER CENTRAL AND NE MO
INTO W CENTRAL IL WITH SOME DEVELOPMENT A BIT FURTHER DOWNSTREAM
TOWARDS N CENTRAL IL AHEAD OF THE UPPER LEVEL TROUGH. APPEARS THAT
MAIN PORTION OF THIS AREA WILL PASS JUST S OF THE ORD AND MDW
THOUGH A COUPLE SHOWERS STILL POSSIBLE TIL AXIS OF UPPER TROUGH
MOVES E AROUND 10Z.
BETWEEN RAINFALL DURING THE EVENING AND CONTINUED WEAK LOW LEVEL
MOISTURE ADVECTION ANTICIPATE IFR CONDITIONS TO PREVAIL EVEN AFTER
THE WEAK SURFACE TROUGH PASSES THROUGH AS HIGHER DEW POINTS LAG A
BIT BEHIND THE TROUGH AND THERE IS ONLY A WEAK PUSH OF THE DRIER
AIR INTO THE AREA OVERNIGHT. MID AND UPPER TROUGHS PASS TO THE E
OVERNIGHT BUT LOWER LEVELS REMAIN SATURATED AND MAY SEE SOME
DRIZZLE DEVELOP DURING THE OVERNIGHT HOURS AS WEAK COLD AIR
ADVECTION IN THE LOWER LEVELS BEGINS.
BY DAYBREAK A DRYING NW LOW LEVEL FLOW IS TO HAVE BECOME MORE
ESTABLISHED IN THE WAKE OF THE SURFACE TROUGH. MODEL GUIDANCE
SHOWS QUICK CLEARING OUT OF THE REMAINING LOW LEVEL MOISTURE BY
MIDDAY THU SO EXPECT A QUICK JUMP FROM IFR CEILINGS TO PRETTY MUCH
SKC THEREAFTER THOUGH MAY A FEW STRATOCU AT LEAS INTO MID
AFTERNOON.
A FAIRLY STRONG SURFACE RIDGE IS TO BE BUILDING SE ACROSS THE
PLAINS LATE TONIGHT AND DURING THU RESULTING A MODERATELY STRONG
WNW-NW LOW LEVEL FLOW OVER THE LOCAL AREA BY THE TIME THE CLOUDS
CLEAR OUT. WITH SURFACE HEATING MIXED LAYER PROGGED TO DEEPEN TO
1-1.5KM WHICH WOULD ALLOW MOMENTUM TRANSFER OF 20-25KT WINDS AT
THIS LEVEL MIXING DOWN TO THE SURFACE RESULTING IN SOME GUSTINESS
FROM MIDDAY UNTIL SUNSET THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE WITH END TIME OF RA/DZ...AND ASSOCIATED VSBY.
* MEDIUM-LOW CONFIDENCE WITH MVFR VSBY THROUGH MORNING...MAY SEE
IFR FOG DEVELOP.
* MEDIUM CONFIDENCE IN TIMING OF CIG IMPROVEMENT TODAY.
* MEDIUM CONFIDENCE IN WIND FORECAST.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR.
SATURDAY...POSSIBLE MVFR CIGS.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...CHANCE RA AND/OR SN WITH MVFR.
TRS
&&
.MARINE...
205 AM CST
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. WINDS WILL REMAIN LIGHT AND VARIABLE FOR THE NEXT SEVERAL
HOURS UNTIL THIS OCCURS. HOWEVER...ONCE IT PASSES OVER THE LAKE
EXPECT WINDS TO BECOME WEST NORTHWESTERLY AND INCREASE TO 20 TO 25
KT BY LATE MORNING AND EARLY AFTERNOON.
THE SURFACE LOW IS EXPECTED TO CONSOLIDATE ACROSS THE UPPER GREAT
LAKES THIS AFTERNOON AND EVENING. MEANWHILE...HIGH PRESSURE ACROSS
THE PLAINS WILL BUILD EASTWARD ACROSS THE MID MISSISSIPPI AND OHIO
VALLEYS. THE COMBINATION OF THESE TWO PRESSURE SYSTEMS WILL
CONTINUE TO PRODUCE A DECENT PRESSURE GRADIENT ACROSS MAKE MICHIGAN
INTO FRIDAY MORNING. THEREFORE WESTERLY WINDS OF 20 TO 25 KT WILL
CONTINUE DURING THIS TIME PERIOD.
THE WINDS WILL ABATE DURING THE DAY ON FRIDAY BEFORE ANOTHER AREA OF
LOW PRESSURE MOVES ACROSS LAKE MICHIGAN FRIDAY NIGHT. ONCE THIS LOW
PASSES BY...WINDS WILL ONCE AGAIN INCREASE...RESULTING IN ANOTHER
EPISODE OF SOME GUSTY NORTHERLY WINDS IN THE 20 TO 30 KT RANGE ON
SATURDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032-ILZ039 UNTIL 9 AM
THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
207 AM CST THU FEB 16 2012
.DISCUSSION...
823 PM CST
THERE WERE SOME SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST BUT
THE GENERAL THEME OF A WET NIGHT WITH TEMPERATURES DROPPING AT A
SNAILS PACE STILL LOOKS GOOD.
AFTER SOME DRIER AIR ALOFT AND LIMITED FOCUS...RAIN HAS SPREAD
OVER A LARGE PORTION OF THE AREA THIS EVENING. THIS APPEARS TO BE
THANKS IN PART TO A LEAD SHORT WAVE PER WV/PROFILER ANALYSIS AND
ASSOCIATED BETTER 850-700MB CONVERGENCE THAT LINES UP WELL WITH
RADAR RETURNS. GIVEN THE RUC ANALYSIS OF THIS FIELD...TRENDS ON
RADAR...AND HIGH AVAILABLE MOISTURE /BASICALLY 200 PERCENT OF
NORMAL PWATS ON DVN AND ILX RAOBS/...THE RAIN AXIS SHOULD
CONTINUE FOR SEVERAL HOURS WHILE GRADUALLY EXPANDING/EVOLVING
SOUTHEAST AS FORCING FROM THE MAIN UPPER LOW APPROACHES. THIS WAVE
STILL HAS A CLOSED CIRCULATION ON WATER VAPOR AND IS TRIGGERING
CONVECTION ACROSS WESTERN MO. BUT THIS IS FORECAST TO DAMPEN IN
THE MORE CONFLUENT FLOW...LIMITING MORE INTENSE FORCING AND
DYNAMIC COOLING EFFECTS. SO WITH MORE LIMITED FORCING HAVE ADDED
DRIZZLE AND FOG MENTION IN THE FORECAST...ESPECIALLY OVERNIGHT.
THE LOW T/TD SPREADS AND DECREASING FLOW WITH THE BAGGY SURFACE
TROUGH MOVING ACROSS SHOULD FURTHER AID IN SOME AREAS OF LIGHT
FOG.
IT STILL IS POSSIBLE TO HAVE SOME WET NON-ACCUMULATING SNOW
TOWARDS THE NORTHWEST FORECAST AREA LATE TONIGHT AND MAYBE A BRIEF
MIX TOWARDS CHICAGO AS THE SYSTEM DEPARTS THU MORNING. WHILE THE
DVN RAOB DID COME IN AROUND 1-2C COOLER IN THE LOWER PROFILE THAN
THE 00Z RUC AND 18Z NAM...IT STILL DEPICTED NEARLY A 4500 FT THICK
LAYER NEAR OR ABOVE FREEZING. IN THE ABSENCE OF STRONG COLD AIR
ADVECTION...A DECREASING CHANCE FOR SNOW IN THE FORECAST
CONTINUES. AS FOR THUNDER...SOME WEAK POSITIVE INSTABILITY IS
PRESENT ON THE ILX SOUNDING WHEN LIFTING PARCELS FROM 850 MB...BUT
THE BETTER ELEVATED INSTABILITY GRADIENT WHICH LINES UP WITH
ONGOING CONVECTION IN MO LOOKS TO STAY TO OUR SOUTH. POCKETS OF
ISOLATED HEAVIER RAIN HAVE BEEN SEEN PER DUAL-POL ANALYSIS. GOING
QPF FORECAST LOOKS ALRIGHT ON MAGNITUDE...BUT DID SHRINK THE AREAL
COVERAGE OF THE FORECAST ONE QUARTER OF AN INCH AND GREATER.
MTF
//PREV DISCUSSION...
317 PM...PRIMARY FORECAST FOCUS REMAINS APPROACHING SYSTEM WITH
MAINLY RAIN/SHOWERS TONIGHT.
AFTER A BRIEF PERIOD OF SOME SUN THIS MORNING...LOW CLOUDS SPREAD
NORTH AND DEVELOPED ACROSS THE AREA ALONG WITH SOME SHOWERS MIDDAY
WHICH HAVE SINCE MOVED OVER THE LAKE. FAIRLY STRONG UPPER WAVE TO
MOVE ACROSS THE AREA TONIGHT...THOUGH IT SLOWLY WEAKENS WITH TIME.
SCATTERED SHOWERS CURRENTLY DEVELOPING FROM KANSAS INTO SOUTHERN
IOWA AND THIS ACTIVITY WILL CONTINUE NORTHEAST ACROSS THE AREA
THIS EVENING INTO EARLY THURSDAY MORNING. LATEST GUIDANCE
SUGGESTS A TREND OF THE HEAVIEST RAIN...OR THE POTENTIAL FOR THE
HEAVIEST RAIN...FALLING ACROSS THE SOUTHERN CWA AND POINTS SOUTH
AND EAST. SO HAVE BACKED OFF ON QPF AMOUNTS SOME ESPECIALLY NORTH
WITH STRONGER CONVECTION FURTHER SOUTH TAKING SOME OF THE
AVAILABLE MOISTURE/QPF. THOUGH SINCE THERE COULD STILL BE SOME
CONVECTIVE ELEMENTS...LOCALIZED RAINFALL TOTALS OF A HALF TO THREE
QUARTERS OF AN INCH ARE STILL POSSIBLE. THERE IS ALSO SOME SMALL
INSTABILITY ALOFT THAT MAY CAUSE A RUMBLE OR TWO OF THUNDER...
MAINLY ACROSS THE FAR SOUTHERN CWA AND WILL CONTINUE WITH NO
MENTION OF THUNDER.
AS FOR ANY SNOW POTENTIAL...NOT MUCH COLD AIR TO WORK WITH THIS
SYSTEM AND DEW POINTS ALREADY CREEPING UP INTO THE MID 30S ACROSS
NORTHERN IL. ANY SNOW WOULD LIKELY RESULT FROM PRECIP COOLING THE
COLUMN ON THE BACK SIDE OF THE PRECIP LATE TONIGHT INTO EARLY
THURSDAY MORNING...RATHER THAN SHARP COLD AIR ADVECTION. AND BY
THE TIME THERE IS ENOUGH COLD AIR FOR PRECIP TO CHANGEOVER TO
SNOW...IT APPEARS PRECIP WILL BE ENDING. THUS HAVE MAINTAINED A
CHANCE OF SNOW ACROSS THE FAR NORTHWEST CWA OVERNIGHT AND THEN A
CHANCE OF RAIN OR SNOW SHOWERS MIXED THURSDAY MORNING...BUT EVEN
IF PRECIP WERE TO GO OVER TO SNOW...GROUND WOULD LIKELY BE WARM
ENOUGH AND WET ENOUGH THAT LITTLE OR NO ACCUMULATION WOULD RESULT.
AND AS NOTED...HUNG ONTO SLIGHT/CHANCE POPS THURSDAY MORNING BUT
ITS ALSO POSSIBLE THAT PRECIP MAY END BY SUNRISE MOST AREAS. IN
ADDITION...IF HEAVIER RAIN/SHOWERS DO END UP FURTHER SOUTH...
PRECIP MIGHT END UP BEING MORE DRIZZLE.
TEMPERATURES CURRENTLY IN THE LOWER 40S WILL SLOWLY FALL INTO THE
MID/UPPER 30S BUT FOR THE MOST PART WILL BE STEADY...PROBABLY NOT
DROPPING SIGNIFICANTLY UNTIL WIDESPREAD PRECIP BEGINS FALLING.
LOWS ACROSS THE NORTHWEST MAY DIP DOWN TO FREEZING BY MORNING BUT
MOST OF THE CWA LIKELY TO STAY JUST ABOVE FREEZING THROUGH
MORNING. CLOUDS BEGIN CLEARING BY LATE THURSDAY MORNING AND WITH
SOME SUN IN THE AFTERNOON...SHOULD SEE TEMPS WARM INTO THE LOWER
40S THURSDAY.
A RIDGE OF HIGH PRESSURE SLIDES BY THURSDAY NIGHT INTO FRIDAY WITH
SOUTHERLY FLOW RETURNING FRIDAY AFTERNOON. DEPENDING ON THE EXTENT
OF INCREASING CLOUDS FRIDAY AFTERNOON...TEMPS WARMING BACK INTO
THE MID/UPPER 40S SEEMS REASONABLE FROM THIS DISTANCE. MODELS THEN
BRING ACROSS ANOTHER WEAK SURFACE LOW FRIDAY NIGHT. APPEARS THE
BULK OF THE PRECIP WITH THIS SYSTEM WILL REMAIN ON THE NORTH SIDE
OF THIS LOW AND NORTH OF THE CWA...BUT A FEW RAIN OR SNOW SHOWERS
APPEAR POSSIBLE ALONG THE TRAILING COLD FRONT LATE FRIDAY NIGHT
INTO SATURDAY MORNING AND INTRODUCED LOW CHANCE POPS DURING THIS
TIME PERIOD. THIS COLD FRONT USHERS IN SOME COLDER AIR...THOUGH
THE MODELS DIFFER ON THE EXTENT OF JUST HOW COLD THIS AIR WILL
BE. DOESN/T APPEAR TOO COLD BUT HIGHS THIS WEEKEND LIKELY ONLY IN
THE 30S.
NEXT WEEK LOOKING BOTH UNSETTLED AND UNCERTAIN AS A POSSIBLE COLD
FRONT MOVES THROUGH THE AREA TUESDAY WITH A STRONGER SYSTEM
LIFTING NORTHEAST ACROSS THE OHIO VALLEY/SOUTHERN LAKES REGION
TOWARD MIDWEEK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* IFR/LIFR CEILINGS AND VISIBILITIES TONIGHT.
* ENDING TIME OF -RA AND POTENTIAL FOR -DZ OVERNIGHT.
* TIMING OF RETURN TO VFR THU.
* GUSTY NW WIND DEVELOPING THU.
TRS
//DISCUSSION...UPDATED 06Z...
SYSTEM MOVING OVER THE MIDWEST IS RATHER DISORGANIZED BASED ON
CLOUD TOP TEMPS SEEN IR SATELLITE AND ON RADAR LOOPS. EVEN THOUGH
A WELL DEFINED UPPER LOW IS STILL SEEN OVER SW MO THERE APPEARS
TO BE MULTIPLE SMALLER SCALE IMPULSES EMBEDDED WITHIN THE OVERALL
LARGE SCALE FLOW.
MID LEVEL TROUGH IS CURRENTLY MOVING OVER SOUTHERN WI AND
NORTHERN IL. TROUGH AXIS AND TRAILING EDGE OF RAIN CURRENTLY OVER
THE AREA EXPECTED TO BE E OF CHI VICINITY BY 07Z BASED ON LATEST
MODEL PROGS AND EXTRAPOLATION OF RECENT RADAR IMAGES.
HOWEVER...ANOTHER AREA OF RAIN CURRENTLY OVER CENTRAL AND NE MO
INTO W CENTRAL IL WITH SOME DEVELOPMENT A BIT FURTHER DOWNSTREAM
TOWARDS N CENTRAL IL AHEAD OF THE UPPER LEVEL TROUGH. APPEARS THAT
MAIN PORTION OF THIS AREA WILL PASS JUST S OF THE ORD AND MDW
THOUGH A COUPLE SHOWERS STILL POSSIBLE TIL AXIS OF UPPER TROUGH
MOVES E AROUND 10Z.
BETWEEN RAINFALL DURING THE EVENING AND CONTINUED WEAK LOW LEVEL
MOISTURE ADVECTION ANTICIPATE IFR CONDITIONS TO PREVAIL EVEN AFTER
THE WEAK SURFACE TROUGH PASSES THROUGH AS HIGHER DEW POINTS LAG A
BIT BEHIND THE TROUGH AND THERE IS ONLY A WEAK PUSH OF THE DRIER
AIR INTO THE AREA OVERNIGHT. MID AND UPPER TROUGHS PASS TO THE E
OVERNIGHT BUT LOWER LEVELS REMAIN SATURATED AND MAY SEE SOME
DRIZZLE DEVELOP DURING THE OVERNIGHT HOURS AS WEAK COLD AIR
ADVECTION IN THE LOWER LEVELS BEGINS.
BY DAYBREAK A DRYING NW LOW LEVEL FLOW IS TO HAVE BECOME MORE
ESTABLISHED IN THE WAKE OF THE SURFACE TROUGH. MODEL GUIDANCE
SHOWS QUICK CLEARING OUT OF THE REMAINING LOW LEVEL MOISTURE BY
MIDDAY THU SO EXPECT A QUICK JUMP FROM IFR CEILINGS TO PRETTY MUCH
SKC THEREAFTER THOUGH MAY A FEW STRATOCU AT LEAS INTO MID
AFTERNOON.
A FAIRLY STRONG SURFACE RIDGE IS TO BE BUILDING SE ACROSS THE
PLAINS LATE TONIGHT AND DURING THU RESULTING A MODERATELY STRONG
WNW-NW LOW LEVEL FLOW OVER THE LOCAL AREA BY THE TIME THE CLOUDS
CLEAR OUT. WITH SURFACE HEATING MIXED LAYER PROGGED TO DEEPEN TO
1-1.5KM WHICH WOULD ALLOW MOMENTUM TRANSFER OF 20-25KT WINDS AT
THIS LEVEL MIXING DOWN TO THE SURFACE RESULTING IN SOME GUSTINESS
FROM MIDDAY UNTIL SUNSET THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CONTINUED IFR REST OF NIGHT.
* HIGH CONFIDENCE IN CONTINUED LIGHT WINDS REST OF NIGHT.
* HIGH CONFIDENCE IN INCREASING NW WINDS DURING THU MORNING.
* MODERATE CONFIDENCE IN ENDING TIME OF -RA.
* MODERATE CONFIDENCE IN OCCURRENCE OF -DZ OVERNIGHT INTO PRE-
DAWN THU.
* MODERATE CONFIDENCE IN RAPID IMPROVEMENT FROM IFR DURING LATER
THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR.
SATURDAY...POSSIBLE MVFR CIGS.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...CHANCE RA AND/OR SN WITH MVFR.
TRS
&&
.MARINE...
205 AM CST
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. WINDS WILL REMAIN LIGHT AND VARIABLE FOR THE NEXT SEVERAL
HOURS UNTIL THIS OCCURS. HOWEVER...ONCE IT PASSES OVER THE LAKE
EXPECT WINDS TO BECOME WEST NORTHWESTERLY AND INCREASE TO 20 TO 25
KT BY LATE MORNING AND EARLY AFTERNOON.
THE SURFACE LOW IS EXPECTED TO CONSOLIDATE ACROSS THE UPPER GREAT
LAKES THIS AFTERNOON AND EVENING. MEANWHILE...HIGH PRESSURE ACROSS
THE PLAINS WILL BUILD EASTWARD ACROSS THE MID MISSISSIPPI AND OHIO
VALLEYS. THE COMBINATION OF THESE TWO PRESSURE SYSTEMS WILL
CONTINUE TO PRODUCE A DECENT PRESSURE GRADIENT ACROSS MAKE MICHIGAN
INTO FRIDAY MORNING. THEREFORE WESTERLY WINDS OF 20 TO 25 KT WILL
CONTINUE DURING THIS TIME PERIOD.
THE WINDS WILL ABATE DURING THE DAY ON FRIDAY BEFORE ANOTHER AREA OF
LOW PRESSURE MOVES ACROSS LAKE MICHIGAN FRIDAY NIGHT. ONCE THIS LOW
PASSES BY...WINDS WILL ONCE AGAIN INCREASE...RESULTING IN ANOTHER
EPISODE OF SOME GUSTY NORTHERLY WINDS IN THE 20 TO 30 KT RANGE ON
SATURDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032-ILZ039 UNTIL 9 AM
THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1109 PM CST WED FEB 15 2012
.DISCUSSION...
823 PM CST
THERE WERE SOME SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST BUT
THE GENERAL THEME OF A WET NIGHT WITH TEMPERATURES DROPPING AT A
SNAILS PACE STILL LOOKS GOOD.
AFTER SOME DRIER AIR ALOFT AND LIMITED FOCUS...RAIN HAS SPREAD
OVER A LARGE PORTION OF THE AREA THIS EVENING. THIS APPEARS TO BE
THANKS IN PART TO A LEAD SHORT WAVE PER WV/PROFILER ANALYSIS AND
ASSOCIATED BETTER 850-700MB CONVERGENCE THAT LINES UP WELL WITH
RADAR RETURNS. GIVEN THE RUC ANALYSIS OF THIS FIELD...TRENDS ON
RADAR...AND HIGH AVAILABLE MOISTURE /BASICALLY 200 PERCENT OF
NORMAL PWATS ON DVN AND ILX RAOBS/...THE RAIN AXIS SHOULD
CONTINUE FOR SEVERAL HOURS WHILE GRADUALLY EXPANDING/EVOLVING
SOUTHEAST AS FORCING FROM THE MAIN UPPER LOW APPROACHES. THIS WAVE
STILL HAS A CLOSED CIRCULATION ON WATER VAPOR AND IS TRIGGERING
CONVECTION ACROSS WESTERN MO. BUT THIS IS FORECAST TO DAMPEN IN
THE MORE CONFLUENT FLOW...LIMITING MORE INTENSE FORCING AND
DYNAMIC COOLING EFFECTS. SO WITH MORE LIMITED FORCING HAVE ADDED
DRIZZLE AND FOG MENTION IN THE FORECAST...ESPECIALLY OVERNIGHT.
THE LOW T/TD SPREADS AND DECREASING FLOW WITH THE BAGGY SURFACE
TROUGH MOVING ACROSS SHOULD FURTHER AID IN SOME AREAS OF LIGHT
FOG.
IT STILL IS POSSIBLE TO HAVE SOME WET NON-ACCUMULATING SNOW
TOWARDS THE NORTHWEST FORECAST AREA LATE TONIGHT AND MAYBE A BRIEF
MIX TOWARDS CHICAGO AS THE SYSTEM DEPARTS THU MORNING. WHILE THE
DVN RAOB DID COME IN AROUND 1-2C COOLER IN THE LOWER PROFILE THAN
THE 00Z RUC AND 18Z NAM...IT STILL DEPICTED NEARLY A 4500 FT THICK
LAYER NEAR OR ABOVE FREEZING. IN THE ABSENCE OF STRONG COLD AIR
ADVECTION...A DECREASING CHANCE FOR SNOW IN THE FORECAST
CONTINUES. AS FOR THUNDER...SOME WEAK POSITIVE INSTABILITY IS
PRESENT ON THE ILX SOUNDING WHEN LIFTING PARCELS FROM 850 MB...BUT
THE BETTER ELEVATED INSTABILITY GRADIENT WHICH LINES UP WITH
ONGOING CONVECTION IN MO LOOKS TO STAY TO OUR SOUTH. POCKETS OF
ISOLATED HEAVIER RAIN HAVE BEEN SEEN PER DUAL-POL ANALYSIS. GOING
QPF FORECAST LOOKS ALRIGHT ON MAGNITUDE...BUT DID SHRINK THE AREAL
COVERAGE OF THE FORECAST ONE QUARTER OF AN INCH AND GREATER.
MTF
//PREV DISCUSSION...
317 PM...PRIMARY FORECAST FOCUS REMAINS APPROACHING SYSTEM WITH
MAINLY RAIN/SHOWERS TONIGHT.
AFTER A BRIEF PERIOD OF SOME SUN THIS MORNING...LOW CLOUDS SPREAD
NORTH AND DEVELOPED ACROSS THE AREA ALONG WITH SOME SHOWERS MIDDAY
WHICH HAVE SINCE MOVED OVER THE LAKE. FAIRLY STRONG UPPER WAVE TO
MOVE ACROSS THE AREA TONIGHT...THOUGH IT SLOWLY WEAKENS WITH TIME.
SCATTERED SHOWERS CURRENTLY DEVELOPING FROM KANSAS INTO SOUTHERN
IOWA AND THIS ACTIVITY WILL CONTINUE NORTHEAST ACROSS THE AREA
THIS EVENING INTO EARLY THURSDAY MORNING. LATEST GUIDANCE
SUGGESTS A TREND OF THE HEAVIEST RAIN...OR THE POTENTIAL FOR THE
HEAVIEST RAIN...FALLING ACROSS THE SOUTHERN CWA AND POINTS SOUTH
AND EAST. SO HAVE BACKED OFF ON QPF AMOUNTS SOME ESPECIALLY NORTH
WITH STRONGER CONVECTION FURTHER SOUTH TAKING SOME OF THE
AVAILABLE MOISTURE/QPF. THOUGH SINCE THERE COULD STILL BE SOME
CONVECTIVE ELEMENTS...LOCALIZED RAINFALL TOTALS OF A HALF TO THREE
QUARTERS OF AN INCH ARE STILL POSSIBLE. THERE IS ALSO SOME SMALL
INSTABILITY ALOFT THAT MAY CAUSE A RUMBLE OR TWO OF THUNDER...
MAINLY ACROSS THE FAR SOUTHERN CWA AND WILL CONTINUE WITH NO
MENTION OF THUNDER.
AS FOR ANY SNOW POTENTIAL...NOT MUCH COLD AIR TO WORK WITH THIS
SYSTEM AND DEW POINTS ALREADY CREEPING UP INTO THE MID 30S ACROSS
NORTHERN IL. ANY SNOW WOULD LIKELY RESULT FROM PRECIP COOLING THE
COLUMN ON THE BACK SIDE OF THE PRECIP LATE TONIGHT INTO EARLY
THURSDAY MORNING...RATHER THAN SHARP COLD AIR ADVECTION. AND BY
THE TIME THERE IS ENOUGH COLD AIR FOR PRECIP TO CHANGEOVER TO
SNOW...IT APPEARS PRECIP WILL BE ENDING. THUS HAVE MAINTAINED A
CHANCE OF SNOW ACROSS THE FAR NORTHWEST CWA OVERNIGHT AND THEN A
CHANCE OF RAIN OR SNOW SHOWERS MIXED THURSDAY MORNING...BUT EVEN
IF PRECIP WERE TO GO OVER TO SNOW...GROUND WOULD LIKELY BE WARM
ENOUGH AND WET ENOUGH THAT LITTLE OR NO ACCUMULATION WOULD RESULT.
AND AS NOTED...HUNG ONTO SLIGHT/CHANCE POPS THURSDAY MORNING BUT
ITS ALSO POSSIBLE THAT PRECIP MAY END BY SUNRISE MOST AREAS. IN
ADDITION...IF HEAVIER RAIN/SHOWERS DO END UP FURTHER SOUTH...
PRECIP MIGHT END UP BEING MORE DRIZZLE.
TEMPERATURES CURRENTLY IN THE LOWER 40S WILL SLOWLY FALL INTO THE
MID/UPPER 30S BUT FOR THE MOST PART WILL BE STEADY...PROBABLY NOT
DROPPING SIGNIFICANTLY UNTIL WIDESPREAD PRECIP BEGINS FALLING.
LOWS ACROSS THE NORTHWEST MAY DIP DOWN TO FREEZING BY MORNING BUT
MOST OF THE CWA LIKELY TO STAY JUST ABOVE FREEZING THROUGH
MORNING. CLOUDS BEGIN CLEARING BY LATE THURSDAY MORNING AND WITH
SOME SUN IN THE AFTERNOON...SHOULD SEE TEMPS WARM INTO THE LOWER
40S THURSDAY.
A RIDGE OF HIGH PRESSURE SLIDES BY THURSDAY NIGHT INTO FRIDAY WITH
SOUTHERLY FLOW RETURNING FRIDAY AFTERNOON. DEPENDING ON THE EXTENT
OF INCREASING CLOUDS FRIDAY AFTERNOON...TEMPS WARMING BACK INTO
THE MID/UPPER 40S SEEMS REASONABLE FROM THIS DISTANCE. MODELS THEN
BRING ACROSS ANOTHER WEAK SURFACE LOW FRIDAY NIGHT. APPEARS THE
BULK OF THE PRECIP WITH THIS SYSTEM WILL REMAIN ON THE NORTH SIDE
OF THIS LOW AND NORTH OF THE CWA...BUT A FEW RAIN OR SNOW SHOWERS
APPEAR POSSIBLE ALONG THE TRAILING COLD FRONT LATE FRIDAY NIGHT
INTO SATURDAY MORNING AND INTRODUCED LOW CHANCE POPS DURING THIS
TIME PERIOD. THIS COLD FRONT USHERS IN SOME COLDER AIR...THOUGH
THE MODELS DIFFER ON THE EXTENT OF JUST HOW COLD THIS AIR WILL
BE. DOESN/T APPEAR TOO COLD BUT HIGHS THIS WEEKEND LIKELY ONLY IN
THE 30S.
NEXT WEEK LOOKING BOTH UNSETTLED AND UNCERTAIN AS A POSSIBLE COLD
FRONT MOVES THROUGH THE AREA TUESDAY WITH A STRONGER SYSTEM
LIFTING NORTHEAST ACROSS THE OHIO VALLEY/SOUTHERN LAKES REGION
TOWARD MIDWEEK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* IFR/LIFR CEILINGS AND VISIBILITIES TONIGHT.
* ENDING TIME OF -RA AND POTENTIAL FOR -DZ OVERNIGHT.
* TIMING OF RETURN TO VFR THU.
* GUSTY NW WIND DEVELOPING THU.
TRS
//DISCUSSION...UPDATED 06Z...
SYSTEM MOVING OVER THE MIDWEST IS RATHER DISORGANIZED BASED ON
CLOUD TOP TEMPS SEEN IR SATELLITE AND ON RADAR LOOPS. EVEN THOUGH
A WELL DEFINED UPPER LOW IS STILL SEEN OVER SW MO THERE APPEARS
TO BE MULTIPLE SMALLER SCALE IMPULSES EMBEDDED WITHIN THE OVERALL
LARGE SCALE FLOW.
MID LEVEL TROUGH IS CURRENTLY MOVING OVER SOUTHERN WI AND
NORTHERN IL. TROUGH AXIS AND TRAILING EDGE OF RAIN CURRENTLY OVER
THE AREA EXPECTED TO BE E OF CHI VICINITY BY 07Z BASED ON LATEST
MODEL PROGS AND EXTRAPOLATION OF RECENT RADAR IMAGES.
HOWEVER...ANOTHER AREA OF RAIN CURRENTLY OVER CENTRAL AND NE MO
INTO W CENTRAL IL WITH SOME DEVELOPMENT A BIT FURTHER DOWNSTREAM
TOWARDS N CENTRAL IL AHEAD OF THE UPPER LEVEL TROUGH. APPEARS THAT
MAIN PORTION OF THIS AREA WILL PASS JUST S OF THE ORD AND MDW
THOUGH A COUPLE SHOWERS STILL POSSIBLE TIL AXIS OF UPPER TROUGH
MOVES E AROUND 10Z.
BETWEEN RAINFALL DURING THE EVENING AND CONTINUED WEAK LOW LEVEL
MOISTURE ADVECTION ANTICIPATE IFR CONDITIONS TO PREVAIL EVEN AFTER
THE WEAK SURFACE TROUGH PASSES THROUGH AS HIGHER DEW POINTS LAG A
BIT BEHIND THE TROUGH AND THERE IS ONLY A WEAK PUSH OF THE DRIER
AIR INTO THE AREA OVERNIGHT. MID AND UPPER TROUGHS PASS TO THE E
OVERNIGHT BUT LOWER LEVELS REMAIN SATURATED AND MAY SEE SOME
DRIZZLE DEVELOP DURING THE OVERNIGHT HOURS AS WEAK COLD AIR
ADVECTION IN THE LOWER LEVELS BEGINS.
BY DAYBREAK A DRYING NW LOW LEVEL FLOW IS TO HAVE BECOME MORE
ESTABLISHED IN THE WAKE OF THE SURFACE TROUGH. MODEL GUIDANCE
SHOWS QUICK CLEARING OUT OF THE REMAINING LOW LEVEL MOISTURE BY
MIDDAY THU SO EXPECT A QUICK JUMP FROM IFR CEILINGS TO PRETTY MUCH
SKC THEREAFTER THOUGH MAY A FEW STRATOCU AT LEAS INTO MID
AFTERNOON.
A FAIRLY STRONG SURFACE RIDGE IS TO BE BUILDING SE ACROSS THE
PLAINS LATE TONIGHT AND DURING THU RESULTING A MODERATELY STRONG
WNW-NW LOW LEVEL FLOW OVER THE LOCAL AREA BY THE TIME THE CLOUDS
CLEAR OUT. WITH SURFACE HEATING MIXED LAYER PROGGED TO DEEPEN TO
1-1.5KM WHICH WOULD ALLOW MOMENTUM TRANSFER OF 20-25KT WINDS AT
THIS LEVEL MIXING DOWN TO THE SURFACE RESULTING IN SOME GUSTINESS
FROM MIDDAY UNTIL SUNSET THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CONTINUED IFR REST OF NIGHT.
* HIGH CONFIDENCE IN CONTINUED LIGHT WINDS REST OF NIGHT.
* HIGH CONFIDENCE IN INCREASING NW WINDS DURING THU MORNING.
* MODERATE CONFIDENCE IN ENDING TIME OF -RA.
* MODERATE CONFIDENCE IN OCCURRENCE OF -DZ OVERNIGHT INTO PRE-
DAWN THU.
* MODERATE CONFIDENCE IN RAPID IMPROVEMENT FROM IFR DURING LATER
THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR.
SATURDAY...POSSIBLE MVFR CIGS.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...CHANCE RA AND/OR SN WITH MVFR.
TRS
&&
.MARINE...
203 PM CST
MAIN MARINE FORECAST CONCERNS ARE THE POTENTIAL FOR A COUPLE OF
PERIODS OF 20-25 KT WINDS OVER THE NEXT FEW DAYS...THURSDAY INTO
THURSDAY NIGHT AND AGAIN SATURDAY INTO SATURDAY NIGHT.
LOW PRESSURE WAS OVER THE SOUTHERN PLAINS OF OKLAHOMA THIS
AFTERNOON...WITH A WEAKER TROUGH EXTENDING THROUGH THE UPPER MIDWEST
TO ANOTHER LOW OVER ONTARIO. THE PLAINS LOW WILL WEAKEN AS IT MOVES
EAST ACROSS ILLINOIS AND INDIANA INTO SOUTHWESTERN LOWER MICHIGAN BY
THURSDAY MORNING...THEN WILL COMBINE WITH THE ONTARIO LOW AS THEY
MOVE EAST OF THE LAKES...EVENTUALLY DEEPENING OVER SOUTHWEST QUEBEC
BY THURSDAY EVENING. ONCE THE LOW AND TROUGH AXIS MOVE ACROSS LAKE
MICHIGAN TONIGHT...WINDS WILL SHIFT TO THE WEST AND INCREASE INTO
THE 15 TO 25 KT RANGE THURSDAY AS THE LOW DEEPENS OFF TO THE EAST.
WINDS WILL GRADUALLY DIMINISH THURSDAY NIGHT...AS HIGH PRESSURE
SLIDES INTO THE LOWER OHIO VALLEY AND WEAKER RIDGING EXTENDS NORTH
INTO THE WESTERN LAKES FRIDAY MORNING. ANOTHER WEAK LOW WILL FOLLOW
ACROSS LAKE MICHIGAN LATE FRIDAY NIGHT AND SATURDAY...WITH NORTHERLY
WINDS PICKING UP AGAIN INTO THE 15 TO 25 KT RANGE SATURDAY AND
SATURDAY NIGHT AS THE GRADIENT TIGHTENS FOR A TIME BETWEEN THE
DEPARTING LOW TO THE EAST AND HIGH PRESSURE SPREADING ACROSS THE
UPPER MIDWEST. THIS HIGH WILL SLOWLY SPREAD EAST ACROSS THE LOWER
OHIO VALLEY AND WESTERN LAKES BY SUNDAY NIGHT...ALLOWING WINDS TO
DIMINISH AHEAD OF THE RIDGE ON SUNDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1015 PM CST WED FEB 15 2012
.DISCUSSION...
823 PM CST
THERE WERE SOME SLIGHT ADJUSTMENTS MADE TO THE GOING FORECAST BUT
THE GENERAL THEME OF A WET NIGHT WITH TEMPERATURES DROPPING AT A
SNAILS PACE STILL LOOKS GOOD.
AFTER SOME DRIER AIR ALOFT AND LIMITED FOCUS...RAIN HAS SPREAD
OVER A LARGE PORTION OF THE AREA THIS EVENING. THIS APPEARS TO BE
THANKS IN PART TO A LEAD SHORT WAVE PER WV/PROFILER ANALYSIS AND
ASSOCIATED BETTER 850-700MB CONVERGENCE THAT LINES UP WELL WITH
RADAR RETURNS. GIVEN THE RUC ANALYSIS OF THIS FIELD...TRENDS ON
RADAR...AND HIGH AVAILABLE MOISTURE /BASICALLY 200 PERCENT OF
NORMAL PWATS ON DVN AND ILX RAOBS/...THE RAIN AXIS SHOULD
CONTINUE FOR SEVERAL HOURS WHILE GRADUALLY EXPANDING/EVOLVING
SOUTHEAST AS FORCING FROM THE MAIN UPPER LOW APPROACHES. THIS WAVE
STILL HAS A CLOSED CIRCULATION ON WATER VAPOR AND IS TRIGGERING
CONVECTION ACROSS WESTERN MO. BUT THIS IS FORECAST TO DAMPEN IN
THE MORE CONFLUENT FLOW...LIMITING MORE INTENSE FORCING AND
DYNAMIC COOLING EFFECTS. SO WITH MORE LIMITED FORCING HAVE ADDED
DRIZZLE AND FOG MENTION IN THE FORECAST...ESPECIALLY OVERNIGHT.
THE LOW T/TD SPREADS AND DECREASING FLOW WITH THE BAGGY SURFACE
TROUGH MOVING ACROSS SHOULD FURTHER AID IN SOME AREAS OF LIGHT
FOG.
IT STILL IS POSSIBLE TO HAVE SOME WET NON-ACCUMULATING SNOW
TOWARDS THE NORTHWEST FORECAST AREA LATE TONIGHT AND MAYBE A BRIEF
MIX TOWARDS CHICAGO AS THE SYSTEM DEPARTS THU MORNING. WHILE THE
DVN RAOB DID COME IN AROUND 1-2C COOLER IN THE LOWER PROFILE THAN
THE 00Z RUC AND 18Z NAM...IT STILL DEPICTED NEARLY A 4500 FT THICK
LAYER NEAR OR ABOVE FREEZING. IN THE ABSENCE OF STRONG COLD AIR
ADVECTION...A DECREASING CHANCE FOR SNOW IN THE FORECAST
CONTINUES. AS FOR THUNDER...SOME WEAK POSITIVE INSTABILITY IS
PRESENT ON THE ILX SOUNDING WHEN LIFTING PARCELS FROM 850 MB...BUT
THE BETTER ELEVATED INSTABILITY GRADIENT WHICH LINES UP WITH
ONGOING CONVECTION IN MO LOOKS TO STAY TO OUR SOUTH. POCKETS OF
ISOLATED HEAVIER RAIN HAVE BEEN SEEN PER DUAL-POL ANALYSIS. GOING
QPF FORECAST LOOKS ALRIGHT ON MAGNITUDE...BUT DID SHRINK THE AREAL
COVERAGE OF THE FORECAST ONE QUARTER OF AN INCH AND GREATER.
MTF
//PREV DISCUSSION...
317 PM...PRIMARY FORECAST FOCUS REMAINS APPROACHING SYSTEM WITH
MAINLY RAIN/SHOWERS TONIGHT.
AFTER A BRIEF PERIOD OF SOME SUN THIS MORNING...LOW CLOUDS SPREAD
NORTH AND DEVELOPED ACROSS THE AREA ALONG WITH SOME SHOWERS MIDDAY
WHICH HAVE SINCE MOVED OVER THE LAKE. FAIRLY STRONG UPPER WAVE TO
MOVE ACROSS THE AREA TONIGHT...THOUGH IT SLOWLY WEAKENS WITH TIME.
SCATTERED SHOWERS CURRENTLY DEVELOPING FROM KANSAS INTO SOUTHERN
IOWA AND THIS ACTIVITY WILL CONTINUE NORTHEAST ACROSS THE AREA
THIS EVENING INTO EARLY THURSDAY MORNING. LATEST GUIDANCE
SUGGESTS A TREND OF THE HEAVIEST RAIN...OR THE POTENTIAL FOR THE
HEAVIEST RAIN...FALLING ACROSS THE SOUTHERN CWA AND POINTS SOUTH
AND EAST. SO HAVE BACKED OFF ON QPF AMOUNTS SOME ESPECIALLY NORTH
WITH STRONGER CONVECTION FURTHER SOUTH TAKING SOME OF THE
AVAILABLE MOISTURE/QPF. THOUGH SINCE THERE COULD STILL BE SOME
CONVECTIVE ELEMENTS...LOCALIZED RAINFALL TOTALS OF A HALF TO THREE
QUARTERS OF AN INCH ARE STILL POSSIBLE. THERE IS ALSO SOME SMALL
INSTABILITY ALOFT THAT MAY CAUSE A RUMBLE OR TWO OF THUNDER...
MAINLY ACROSS THE FAR SOUTHERN CWA AND WILL CONTINUE WITH NO
MENTION OF THUNDER.
AS FOR ANY SNOW POTENTIAL...NOT MUCH COLD AIR TO WORK WITH THIS
SYSTEM AND DEW POINTS ALREADY CREEPING UP INTO THE MID 30S ACROSS
NORTHERN IL. ANY SNOW WOULD LIKELY RESULT FROM PRECIP COOLING THE
COLUMN ON THE BACK SIDE OF THE PRECIP LATE TONIGHT INTO EARLY
THURSDAY MORNING...RATHER THAN SHARP COLD AIR ADVECTION. AND BY
THE TIME THERE IS ENOUGH COLD AIR FOR PRECIP TO CHANGEOVER TO
SNOW...IT APPEARS PRECIP WILL BE ENDING. THUS HAVE MAINTAINED A
CHANCE OF SNOW ACROSS THE FAR NORTHWEST CWA OVERNIGHT AND THEN A
CHANCE OF RAIN OR SNOW SHOWERS MIXED THURSDAY MORNING...BUT EVEN
IF PRECIP WERE TO GO OVER TO SNOW...GROUND WOULD LIKELY BE WARM
ENOUGH AND WET ENOUGH THAT LITTLE OR NO ACCUMULATION WOULD RESULT.
AND AS NOTED...HUNG ONTO SLIGHT/CHANCE POPS THURSDAY MORNING BUT
ITS ALSO POSSIBLE THAT PRECIP MAY END BY SUNRISE MOST AREAS. IN
ADDITION...IF HEAVIER RAIN/SHOWERS DO END UP FURTHER SOUTH...
PRECIP MIGHT END UP BEING MORE DRIZZLE.
TEMPERATURES CURRENTLY IN THE LOWER 40S WILL SLOWLY FALL INTO THE
MID/UPPER 30S BUT FOR THE MOST PART WILL BE STEADY...PROBABLY NOT
DROPPING SIGNIFICANTLY UNTIL WIDESPREAD PRECIP BEGINS FALLING.
LOWS ACROSS THE NORTHWEST MAY DIP DOWN TO FREEZING BY MORNING BUT
MOST OF THE CWA LIKELY TO STAY JUST ABOVE FREEZING THROUGH
MORNING. CLOUDS BEGIN CLEARING BY LATE THURSDAY MORNING AND WITH
SOME SUN IN THE AFTERNOON...SHOULD SEE TEMPS WARM INTO THE LOWER
40S THURSDAY.
A RIDGE OF HIGH PRESSURE SLIDES BY THURSDAY NIGHT INTO FRIDAY WITH
SOUTHERLY FLOW RETURNING FRIDAY AFTERNOON. DEPENDING ON THE EXTENT
OF INCREASING CLOUDS FRIDAY AFTERNOON...TEMPS WARMING BACK INTO
THE MID/UPPER 40S SEEMS REASONABLE FROM THIS DISTANCE. MODELS THEN
BRING ACROSS ANOTHER WEAK SURFACE LOW FRIDAY NIGHT. APPEARS THE
BULK OF THE PRECIP WITH THIS SYSTEM WILL REMAIN ON THE NORTH SIDE
OF THIS LOW AND NORTH OF THE CWA...BUT A FEW RAIN OR SNOW SHOWERS
APPEAR POSSIBLE ALONG THE TRAILING COLD FRONT LATE FRIDAY NIGHT
INTO SATURDAY MORNING AND INTRODUCED LOW CHANCE POPS DURING THIS
TIME PERIOD. THIS COLD FRONT USHERS IN SOME COLDER AIR...THOUGH
THE MODELS DIFFER ON THE EXTENT OF JUST HOW COLD THIS AIR WILL
BE. DOESN/T APPEAR TOO COLD BUT HIGHS THIS WEEKEND LIKELY ONLY IN
THE 30S.
NEXT WEEK LOOKING BOTH UNSETTLED AND UNCERTAIN AS A POSSIBLE COLD
FRONT MOVES THROUGH THE AREA TUESDAY WITH A STRONGER SYSTEM
LIFTING NORTHEAST ACROSS THE OHIO VALLEY/SOUTHERN LAKES REGION
TOWARD MIDWEEK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 04Z...
* IFR/LIFR CEILINGS AND VISIBILITIES TONIGHT.
* ENDING TIME OF -RA AND POTENTIAL FOR -DZ OVERNIGHT.
* TIMING OF RETURN TO VFR THU.
TRS
//DISCUSSION...UPDATED 00Z...
SYSTEM MOVING FROM THE PLAINS OVER THE MIDWEST IS RATHER
DISORGANIZED BASED ON CLOUD TOP TEMPS SEEN IR SATELLITE AND ON
RADAR LOOPS. EVEN THOUGH A WELL DEFINED UPPER LOW IS SEEN OVER
EASTERN KS THERE APPEARS TO BE MULTIPLE SMALLER SCALE IMPULSES
EMBEDDED WITHIN THE OVERALL LARGE SCALE FLOW.
LATEST MODEL GUIDANCE INDICATING THAT MAIN RAIN AREA WILL REMAIN
TO THE SW THROUGH S AND E OF THE LOCAL TERMINALS TONIGHT WHERE
BEST FORCING MAXIMIZED AHEAD OF THE UPPER TROUGH PROGGED TO REACH
THE IL-IN BORDER BY 12Z THU. HOWEVER...STILL EXPECT A PERIOD OR
PERIODS OF RAIN THIS EVENING AND INTO THE OVERNIGHT AS MID AND
UPPER LEVEL ASCENT MOVES OVER THE LOCAL AREA.
AN AREA OF RAIN HAS BEEN GRADUALLY MOVING ENE FROM SE IA TO N
CENTRAL IL OVER THE LAST FEW HOURS THOUGH LEADING EDGE APPEARED
TO BE DISSIPATING THE FURTHER E IT GOT INTO IL. MEASUREMENT OF
MOISTURE FROM AN AIRCRAFT DESCENT INTO MDW AT 2132Z SHOWED A DRY
LAYER FROM 800 TO 700 HPA WHICH WAS LEADING TO THE DELAYED
EASTWARD PROGRESS OF THIS LEADING EDGE AS COMPARED EARLIER
ARRIVAL USING EXTRAPOLATION OF RADAR ECHOES. LATEST FRAMES OF
RADAR LOOP SHOWING THE RAIN RECENTLY MAKING STEADY PROGRESS
ACROSS N CENTRAL IL AS THE DRY LAYER HAS BECOME SATURATED.
MEANWHILE...AS S TO SSE LOW LEVEL FLOW CONTINUED TO ADVECT MID
AND UPPER 30S F DEW POINTS INTO THE AREA CEILINGS JUST S OF MDW
AND ORD HAD FALLEN TO BELOW 010 AND VISIBILITIES TO GENERALLY 3 TO
5 SM. THESE CONDITIONS ARE EXPECTED TO CONTINUE TO SPREAD
NORTHWARDS ACROSS FAR NE IL EARLY THIS EVENING EVEN THOUGH THE LOW
LEVEL FLOW IS PROGGED TO WEAKEN WITH TIME AS A WEAK SURFACE LOW OR
TROUGH MOVES E ACROSS THE MS RIVER DURING THE EARLY AND MID
EVENING.
ANY LARGER SCALE LIFT IS PROGGED TO BE E OF THE LOCAL AREA BY
AROUND 09Z BUT MID AND LOWER LEVELS REMAIN SATURATED UNTIL AROUND
12Z SO ANTICIPATE IFR CEILINGS TO PERSIST THROUGH THE NIGHT WITH
OCCASIONAL DRIZZLE DURING THE LATE NIGHT AND PRE DAWN HOURS. BY
DAYBREAK A DRYING NW LOW LEVEL FLOW IS TO HAVE BECOME ESTABLISHED
IN THE WAKE OF THE SURFACE...MID AND UPPER LEVEL TROUGHS. MODEL
GUIDANCE SHOWS QUICK CLEARING OUT OF THE REMAINING LOW LEVEL
MOISTURE BY MIDDAY THU SO EXPECT A QUICK JUMP FROM IFR CEILINGS
TO PRETTY MUCH SKC THEN.
A FAIRLY STRONG SURFACE RIDGE IS TO BE BUILDING SE ACROSS THE
PLAINS LATE TONIGHT AND DURING THU RESULTING A MODERATELY STRONG
WNW-NW LOW LEVEL FLOW OVER THE LOCAL AREA BY THE TIME THE CLOUDS
CLEAR OUT. WITH SURFACE HEATING MIXED LAYER PROGGED TO DEEPEN TO
1-1.5KM WHICH WOULD ALLOW MOMENTUM TRANSFER OF 20-25KT WINDS AT
THIS LEVEL MIXING DOWN TO THE SURFACE RESULTING IN SOME GUSTINESS
FROM MIDDAY UNTIL SUNSET THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 04Z...
* HIGH CONFIDENCE IN CONTINUED IFR REST OF NIGHT.
* HIGH CONFIDENCE IN CONTINUED LIGHT WINDS REST OF NIGHT.
* HIGH CONFIDENCE IN ENDING TIME OF -RA.
* MODERATE CONFIDENCE IN OCCURRENCE OF -DZ OVERNIGHT INTO PRE-
DAWN THU.
* MODERATE CONFIDENCE IN RAPID IMPROVEMENT FROM IFR DURING LATER
THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR.
SATURDAY...POSSIBLE MVFR CIGS.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...CHANCE RA AND/OR SN WITH MVFR.
TRS
&&
.MARINE...
203 PM CST
MAIN MARINE FORECAST CONCERNS ARE THE POTENTIAL FOR A COUPLE OF
PERIODS OF 20-25 KT WINDS OVER THE NEXT FEW DAYS...THURSDAY INTO
THURSDAY NIGHT AND AGAIN SATURDAY INTO SATURDAY NIGHT.
LOW PRESSURE WAS OVER THE SOUTHERN PLAINS OF OKLAHOMA THIS
AFTERNOON...WITH A WEAKER TROUGH EXTENDING THROUGH THE UPPER MIDWEST
TO ANOTHER LOW OVER ONTARIO. THE PLAINS LOW WILL WEAKEN AS IT MOVES
EAST ACROSS ILLINOIS AND INDIANA INTO SOUTHWESTERN LOWER MICHIGAN BY
THURSDAY MORNING...THEN WILL COMBINE WITH THE ONTARIO LOW AS THEY
MOVE EAST OF THE LAKES...EVENTUALLY DEEPENING OVER SOUTHWEST QUEBEC
BY THURSDAY EVENING. ONCE THE LOW AND TROUGH AXIS MOVE ACROSS LAKE
MICHIGAN TONIGHT...WINDS WILL SHIFT TO THE WEST AND INCREASE INTO
THE 15 TO 25 KT RANGE THURSDAY AS THE LOW DEEPENS OFF TO THE EAST.
WINDS WILL GRADUALLY DIMINISH THURSDAY NIGHT...AS HIGH PRESSURE
SLIDES INTO THE LOWER OHIO VALLEY AND WEAKER RIDGING EXTENDS NORTH
INTO THE WESTERN LAKES FRIDAY MORNING. ANOTHER WEAK LOW WILL FOLLOW
ACROSS LAKE MICHIGAN LATE FRIDAY NIGHT AND SATURDAY...WITH NORTHERLY
WINDS PICKING UP AGAIN INTO THE 15 TO 25 KT RANGE SATURDAY AND
SATURDAY NIGHT AS THE GRADIENT TIGHTENS FOR A TIME BETWEEN THE
DEPARTING LOW TO THE EAST AND HIGH PRESSURE SPREADING ACROSS THE
UPPER MIDWEST. THIS HIGH WILL SLOWLY SPREAD EAST ACROSS THE LOWER
OHIO VALLEY AND WESTERN LAKES BY SUNDAY NIGHT...ALLOWING WINDS TO
DIMINISH AHEAD OF THE RIDGE ON SUNDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1113 PM CST WED FEB 15 2012
...UPDATE TO AVIATION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 353 PM CST WED FEB 15 2012
TONIGHT:
THE NEAR TERM/MESOSCALE CONCERN FOR TONIGHT WAS WHAT TO DO WITH POPS
FROM THE LATEST KDDC WSR-88D TRENDS. THIS PRECIPITATION IS BEING CAUSED
BY A 700 HPA DEFORMATION AXIS ON THE BACKSIDE OF A SHORTWAVE TROUGH.
RUC AND PARTICULARLY HRRR WERE AGGRESSIVE WITH FORECAST COMPOSITE REFLECTIVITIES
THIS MORNING. IN ADDITION, 700 HPA OMEGA WAS ALSO NOTED IN THE SAME
REGION. THE 700 HPA DEFORMATION ZONE PER SATELLITE OBSERVATIONS IS
BECOMING STRETCHED ALONG AN AXIS OF DILATATION. THEREFORE HAVE TRIMMED
THE POPS EVEN FURTHER FROM AN UPDATE THIS MORNING WITH THE AERIAL COVERAGE
OF SHOWERS DIMINISHING TO NOTHING BY 00Z TONIGHT.
MODELS SHOW THAT AFTER 00Z, LOWER DEWPOINT ADVECTION WILL OCCUR AT THE
SURFACE. FORECAST SOUNDINGS ALSO SHOW A DRYING IN THE LOW TO MID LEVELS.
THEREFORE HAVE A CLEARING TREND IN THE SKY GRIDS. A LIGHT NORTHWESTERLY
TO NORTHERLY WIND IS EXPECTED OVERNIGHT. OVERNIGHT LOWS WILL BE PRIMARILY
IN THE 20S DEG F.
THURSDAY:
A FORECAST CONCERN THAT WAS MENTIONED IN THE TAF SECTION BELOW WAS THE
POTENTIAL FOR FREEZING FOG. MOS GUIDANCE WAS AGGRESSIVE, INCLUDING LAMP
GUIDANCE, IN BRINGING LOW STRATUS AND FOG BACK TO THE REGION TOMORROW.
BUFKIT FORECAST SOUNDINGS SHOW THAT THE LAYER OF SATURATION IS NEAR
THE SURFACE AND DOESN`T EXTEND VERY FAR UP IN THE ATMOSPHERIC COLUMN
FOR CONSIDERABLE DRYING/LARGE DEWPOINT DEPRESSIONS ARE FORECAST. AS
A RESULT, WILL NOT BRING THE MENTION OF FREEZING FOG IN THE FORECAST
FOR NOW. FROST LOOKS MORE LIKELY AT THE SURFACE. EVEN IF FREEZING
FOG DOES OCCUR, IT SHOULD BE VERY PATCHY DUE TO DRY AIR IMMEDIATELY
ABOVE THE SURFACE, INCLUDING WITHIN THE BOUNDARY LAYER.
WINDS TOMORROW MORNING WILL BE LIGHT AND VARIABLE AS A CENTER OF HIGH
PRESSURE MOVES ACROSS KANSAS. SOUTHERLY WINDS WILL DEVELOP BY TOMORROW
AFTERNOON ACROSS THE FA ON THE WEST SIDE OF THE DEPARTING HIGH. HIGHS
TOMORROW SHOULD BE IN THE UPPER 40S AND NEAR 50 DEG F. NO PRECIPITATION
IS EXPECTED IN THE WAKE OF THE DEPARTING UPPER LEVEL SHORTWAVE TROUGH
AND WITH SUBSIDENCE EXPECTED THROUGH THE ATMOSPHERIC COLUMN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 353 PM CST WED FEB 15 2012
A FAIRLY ACTIVE UPPER LEVEL FLOW PATTERN IS FORECAST TO CONTINUE THROUGH
THE EXTENDED PERIOD. AT THE BEGINNING OF THE PERIOD A BROAD TROUGH WILL
BE SITUATED FROM HUDSON BAY INTO THE UPPER MIDWEST AND GREAT LAKES REGION
WITH A SHORTWAVE TROUGH DROPPING SOUTH OUT OF CANADA INTO THE NORTHERN
HIGH PLAINS. A TROUGH/CLOSED LOW WILL BE OVER THE DESERT SOUTHWEST
INTO NORTHWEST MEXICO. THE GFS MODEL SHOWS THE NORTHERN PLAINS SHORTWAVE
PHASING WITH THE SOUTHWEST CONUS SYSTEM WITH THE RESULTANT TROUGH MOVING
INTO THE MISSISSIPPI VALLEY BY LATE IN THE WEEKEND. THIS MODEL ALSO
BREAKS OUT SOME LIGHT PRECIPITATION OVER THE SOUTHERN PART OF THE
FORECAST AREA SATURDAY NIGHT.
THE ECMWF AND CANADIAN MODELS SHOW THE TWO SYSTEMS REMAINING SEPARATE
WITH BOTH SYSTEMS PASSING BY EITHER NORTH OR SOUTH OF THE CENTRAL
HIGH PLAINS. THE GFS HAS STRUGGLED WITH THIS SYSTEM OVER THE PAST
SEVERAL RUNS WHICH LEADS LESS CREDENCE TO THAT MODEL SOLUTION.
WILL GO WITH A DRY FORECAST FOR THAT TIME PERIOD.
WHILE THIS WAVE IS MOVING EAST OF THE CENTRAL CONUS...ANOTHER SYSTEM
WILL BE MOVING INTO THE ROCKIES. BY SUNDAY NIGHT AND MONDAY THE ECMWF
SHOWS A PIECE OF THIS WAVE EJECTING OUT OVER WESTERN KANSAS WITH PRECIPITATION
BREAKING OUT OVER WESTERN KANSAS. THE MODELS HAVE DIFFERING SOLUTIONS
IN HOW THIS WAVE WILL EVOLVE AND WHEN IT WILL MOVE OUT THROUGH THE
CENTRAL CONUS. NOT REAL CONFIDENT IN ANY SOLUTION BUT THE ECMWF
SEEMS TO SHOW A LITTLE MORE CONTINUITY WITH ITS PREVIOUS RUNS. THE
LATEST CR INIT HAS CHANCE/SLIGHT CHANCE POPS ESPECIALLY ACROSS THE
NORTHERN 2/3RDS OFF THE CWA WHICH LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM CST WED FEB 15 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES THROUGH
LATE THURSDAY EVENING. AS FOR WINDS, SURFACE HIGH PRESSURE IN
NORTHEASTERN COLORADO WILL DRIFT EAST INTO WESTERN KANSAS EARLY
THIS MORNING THEN PUSH FURTHER EASTWARD ACROSS EASTERN KANSAS INTO
MISSOURI THIS AFTERNOON AND EVENING. THIS WILL RESULT IN LIGHT AND
VARIABLE WINDS ACROSS WESTERN KANSAS THROUGH THURSDAY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 48 26 50 / 10 0 0 10
GCK 19 48 24 51 / 10 0 0 0
EHA 21 49 27 53 / 10 0 0 10
LBL 22 51 25 53 / 10 0 0 10
HYS 21 47 26 47 / 10 0 0 0
P28 26 50 27 54 / 10 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM....GERARD
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1213 AM EST THU FEB 16 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 425 PM EST WED FEB 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED SPLIT FLOW PATTERN WITH
TROUGHING OVER THE WRN CONUS AND A FLAT RIDGE OVER THE EAST. ONE NRN
STREAM SHORTWAVE TROUGH WAS LOCATED OVER NW MN WITH ANOTHER TRAILING
OVER SRN SASK INTO NW ND. A VIGOROUS SRN STREAM SHRTWV MOVING FROM
THE TX/OK PANHANDLE INTO SE KS. AT THE SFC...A WEAK TROUGH EXTENDED
FROM NW ONTARIO THROUGH WRN MN LEAVING LIGHT SW FLOW OVER THE NRN
GREAT LAKES. AN AREA OF LIGHT SNOW FROM SRN MN INTO WRN WI WAS
SUPPORTED BY 290K-295K ISENTROPIC ASCENT AHEAD OF THE TROUGH.
TONIGHT AND THU...RADAR TRENDS AND NAM ISENTROPIC PROGS SUGGEST THAT
THE INITIAL AREAS OF PCPN WILL LIFT INTO THE SW CWA THIS EVENING.
HOWEVER...WITH LITTLE INCREASE IN INTENSITY EXPECTED...ONLY
MENTIONED CHANCE POPS WITH SNOW ACCUMULATION OF A HALF INCH OR LESS.
AS THE LAGGING SHORTWAVE MOVES TOWARD THE UPPER MS
VALLEY...INCREASING 700-300 MB QVECTOR CONV WITH THE DEEPENING MID
LEVEL TROUGH WILL ALSO PROVIDE ADDITIONAL SUPPORT FOR AREAS OF LIGHT
SNOW. AGAIN WITH ONLY MODERATE FORCING AND MOISTURE INFLOW...KEPT
ONLY CHANCE POPS WITH SNOW ACCUMULATIONS LESS THAN AN INCH.
HOWEVER...OVER THE ERN CWA...SLIGHTLY GREATER MOISTURE ADVECTION AND
ISENTROPIC ASCENT SHOULD BE ENOUGH FOR MORE WIDESPREAD OR SLIGHTLY
HEAVIER PCPN WITH SNOW AMOUNTS TO AROUND AN INCH.
WITH DEWPOINTS REMAINING IN THE MID 20S OVER THE AREA...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL...WITH READINGS ONLY FALLING INTO THE
MID AND UPPER 20S. CLOUDS AND LIGHT PCPN SHOULD LIMIT MAX READINGS
TO THE MID 30S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 PM EST WED FEB 15 2012
WE START THE PERIOD 00Z FRI WITH A 600MB SHORTWAVE TROUGH AXIS OVER
THE ERN CWA...ANOTHER WEAKER SHORTWAVE OVER NRN MN...AND ANOTHER
STRONGER SHORTWAVE JUST N OF MANITOBA. THIS RESULTS IN A
BROAD...WEAK SFC LOW TO OUR NE...AND A WEAK SFC RIDGE OVER MN. WITH
NW TO WNW LOW LEVEL WINDS...850MB TEMPS AROUND -10C...AND DEEP
MOISTURE...EXPECT SOME LIGHT UPSLOPE SNOW OVER THE WRN CWA AND SOME
LIGHT LAKE ENHANCED SNOW OVER THE ERN CWA AT THE START OF THE
PERIOD.
AS THE NRN MN SHORTWAVE MOVES INTO THE AREA LATE THU NIGHT...LES MAY
BECOME A LITTLE MORE ORGANIZED. BY 12Z FRI...850MB TEMPS WILL HAVE
DECREASED TO AROUND -12C WITH LOW LEVEL WINDS FROM THE NW TO WNW.
WILL DECREASE POPS SOME AFTER THE INITIAL SHORTWAVE PASSAGE AT THE
START OF THE PERIOD...THEN INCREASE POPS LATER THU NIGHT. STILL
EXPECT NOTHING MORE THAN LIGHT LES...WITH MINOR ACCUMULATIONS OF
LESS THAN AN INCH THROUGH THU NIGHT.
850MB TEMPS WILL CONTINUE TO STEADILY DECREASE FRI...AND BE DOWN TO
-14C BY 00Z SAT...BUT SUBSIDENCE BEHIND THE THU NIGHT SHORTWAVE AND
DAYTIME MIXING WILL LEAD TO LES NOT REALLY INCREASING MUCH THROUGH
THE DAY. CHANCE POPS LOOK GOOD FOR FRIDAY IN THE NW TO WNW
SNOWBELTS...WITH AROUND AN INCH OF ADDITIONAL SNOWFALL ACCUMULATIONS.
FRI NIGHT AND SAT ARE MORE COMPLEX AND UNCERTAIN AS A STRONGER
SHORTWAVE TROUGH MOVES OVER THE AREA. MODELS HAVE SHOWN BOTH RUN TO
RUN AND MODEL TO MODEL DISAGREEMENT ON THE STRENGTH AND TIMING OF
THE SHORTWAVE...WHICH HAS A BIG IMPACT ON PRECIP TIMING/COVERAGE.
BESIDES THE OBVIOUS TIMING DIFFERENCES...ONE OF THE BIGGER
DIFFERENCES BETWEEN THE MODELS RESULTS FROM THE STRENGTH OF THE
SYSTEM. ALL MODELS BRING A DEEPENING SFC LOW SOMEWHERE S OF THE
CWA...BUT THE EXACT TRACK OF THE LOW IS WHAT IS IN QUESTION. THE
12Z/15 GFS IS THE STRONGEST AND FARTHEST N WITH THE SFC LOW...WHICH
WOULD BRING A COUPLE OF INCHES OF SNOW TO AREAS OF MENOMINEE COUNTY
AND FAR ERN UPPER MI. THE GFS SOLUTION WOULD ALSO BRING LOW LEVEL
WINDS FROM THE NNE...WHEREAS MOST OTHER MODELS SHOW NW TO NNW LOW
LEVEL WINDS...WHICH WOULD MAKES FOR BIG DIFFERENCES IN LES. WILL NOT
USE THE GFS SOLUTION SINCE IT IS MORE OF AN OUTLIER. THUS...WILL
HAVE HIGH CHANCE TO LOW LIKELY POPS IN NNW TO NW WIND SNOWBELTS FRI
NIGHT AND SAT...DIMINISHING LATE SAT AS SFC HIGH PRESSURE MOVES IN.
DAYS 4 THROUGH 7 (SUNDAY THROUGH NEXT WEDNESDAY)...
MODELS COME INTO BRIEF AGREEMENT AGAIN ON MON WITH AN UPPER LEVEL
RIDGE OVER THE CWA. SFC HIGH PRESSURE E AND LOW PRESSURE W RESULTS
IN WAA OVER THE AREA...WHICH WILL ALLOW HIGHS MON TO BE IN THE MID
30S. MODELS THEN DIVERGE SIGNIFICANTLY WITH SOLUTIONS FROM MON NIGHT
THROUGH THE REST OF THE FORECAST PERIOD. MODELS SHOWS A COUPLE OF
TROUGHS MOVING THROUGH...THE FIRST SOMETIME BETWEEN MON NIGHT
THROUGH TUE NIGHT AND THE OTHER POSSIBLY MOVING INTO THE AREA
SOMETIME LATE WED. SIGNIFICANT RUN TO RUN ERRORS AND MODEL
DISAGREEMENT MAKE FOR LOW CONFIDENCE IN MODELS PAST MON. THE PERIOD
SHOULD GENERALLY BE ABOVE NORMAL WITH RESPECT TO TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1213 AM EST THU FEB 16 2012
PER SATELLITE IMAGERY...ONE SHORTWAVE LIFTING NE JUST NW OF LAKE
SUPERIOR IS BEING FOLLOWED BY ANOTHER MOVING INTO NRN MN. WITH
LATTER WAVE MOVING INTO THE UPPER LAKES THIS MORNING...MAY SEE A
LITTLE -SN...MAINLY AT KCMX/KSAW. PER UPSTREAM OBS...LOWER CIGS WILL
ARRIVE...MVFR AT KIWD AND PROBABLY IFR AT KCMX...ESPECIALLY ONCE
WINDS TAKE ON AN UPSLOPE WESTERLY COMPONENT. AT KSAW...LIGHT
SOUTHERLY UPSLOPE WINDS AHEAD OF APPROACHING WAVE WILL PROBABLY
BRING IFR CONDITIONS TO KSAW OVER THE NEXT FEW HRS AS OBS SHOW
EXPANDING FOG/STRATUS LIFTING N FROM VCNTY OF LAKE MI. ONCE WINDS
SHIFT WESTERLY WITH PASSAGE OF COLD FRONT...CONDITIONS WILL IMPROVE
TO MVFR AT KSAW. MVFR CONDITIONS SHOULD BE THE RULE AT ALL SITES FOR
THE BULK OF THE DAY...THOUGH CLOUDS MAY LIFT TO VFR LATER IN THE DAY
AT KIWD AND ESPECIALLY AT KSAW WHERE WINDS WILL BE DOWNSLOPING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EST WED FEB 15 2012
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 20 TO 30 KT RANGE THU
INTO THU NIGHT IN THE WAKE OF A TROUGH MOVING THROUGH THE REGION.
OTHERWISE...CONDITIONS WILL REMAIN RELATIVELY TRANQUIL THIS WEEK.
LOW PRESSURE WILL CROSS THE GREAT LAKES THROUGH THE WEEKEND...AND
WINDS WILL GENERALLY BE BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EST THU FEB 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST AND OFFSHORE THIS MORNING. A WEAK
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
REGION THURSDAY AFTERNOON AND EVENING.
&&
.NEAR TERM /TONIGHT/...
AS OF 300 AM THURSDAY...
SURFACE HIGH PRESSURE HAS SHIFTED OFFSHORE THIS MORNING...AND ONCE
CALM WINDS ARE NOW BEGINNING TO STIR OUT OF THE SOUTHEAST. PRECIP
ASSOCIATED WITH A DEAMPLIFYING SHORTWAVE LIFTING INTO THE OHIO
VALLEY IS ALREADY OVER EASTERN TN...EXTENDING SOUTH TO AN AREA
NON-SEVERE CONVECTION MOVING ALONG A SURFACE WARM FRONT NEAR THE
GULF COAST. THIS APPEARS TO BE 2 TO 3 HOURS FASTER THAN MOST HI-RES
WRF MODELS HAVE BEEN FORECASTING. OPERATIONAL MODELS ARE STILL
STRUGGLING TO HANDLE QPF NORTH OF THE CONVECTION ALONG THE GULF
COAST....IN MOST CASES OVER FORECASTING THE ONE TO TWO TENTHS OF AN
INCH OBSERVED OVER NORTHERN AL AND EASTERN TN AT 06Z. THE
AFOREMENTIONED SURFACE WARM FRONT IS FORECAST TO LIFT NORTH INTO SC
AND EVEN COASTAL NC LATER TODAY...AND OPERATIONAL MODELS FOCUS AS
MUCH AS 0.5" TO 0.75" ALONG THE WARM FRONT NEAR THE SC/NC BORDER.
HOWEVER...THERE IS NO SUPPORT FOR THIS FROM HI-RES WRF RUNS...AND
RADAR TRENDS LEAN TOWARD LIGHTER AMOUNTS...WITH THE BULK OF PRECIP
EITHER LIFTING NORTH INTO VA OR REMAINING SUPPRESSED TO GA/SC. WHILE
PRECIP WILL BE LIGHT THIS MORNING...WE HAVE SPED UP POPS TO LIKELY
IN THE WEST BY 15Z AND CATEGORICAL NEARLY EVERYWHERE BY 18Z. WE
WILL KEEP QPF AROUND 0.30" OR LESS. CONCERNING POTENTIAL FOR
THUNDER...MID LEVEL LAPSE RATES WILL BE POOR OVER CENTRAL NC TODAY
AND THE NORTHWARD SURGE OF TRUE WARM SECTOR AIR WILL BE CONFINED TO
THE COAST IF EVEN THAT FAR NORTH. THUS WE WILL LEAVE THUNDER OUT OF
THE FORECAST.
TEMPS THIS MORNING RANGE FROM THE MID AND UPPER 40S SOUTH AND WEST
TO MID AND UPPER 30S IN THE EAST. HEATING TODAY WILL BE HINDERED BY
CLOUD COVER AND PRECIP...MOSTLY IN THE WEST...BUT AIDED BY WARM
ADVECTION IN THE EAST. THUS HIGHS SHOULD VARY WIDELY FROM LOWER 50S
WEST TO LOWER 60S EAST.
TONIGHT...MODELS ARE QUICK TO DRY OUR THE MID LAYERS BY 00Z ALMOST
EVERYWHERE. THUS PRECIP SHOULD COME TO AN END DURING THE EVENING
HOURS. HOWEVER... LOW LEVEL MOISTURE IS MUCH SLOWER TO SCOUR...SO IF
WINDS BECOME LIGHT ENOUGH...THERE COULD BE A SHORT PERIOD OF FOG
OVERNIGHT. STATISTICAL GUIDANCE SHOWS NO SIGNS OF FOG
POTENTIAL...BUT THE SREF DOES GIVE SOME HIGHER PROBABILITIES AFTER
06Z. MOST GUIDANCE LOOKS TOO WARM OVERNIGHT GIVEN THAT SKIES SHOULD
CLEAR AND WINDS WILL BECOME LIGHT NORTHWESTERLY. THE CURRENT
FORECAST IS ALREADY BELOW MOST GUIDANCE...SO WILL LEAVE LOWS AT
27-44.
HIGH PRESSURE WILL BUILD BRIEFLY ACROSS VA ON FRIDAY...BUT MID AND
HIGH CLOUDS SHOULD QUICKLY SPREAD BACK OVERHEAD AS A LOW PRESSURE
SYSTEM BEGINS TO TAKE SHAPE OVER THE GULF COAST. WILL KEEP HIGHS IN
LINE WITH 1000-850MB THICKNESS SCHEMES (1335-1340M)..WHICH YIELDS
LOWER 60S AREAWIDE. WITH THICKENING CLOUDS FRIDAY NIGHT...LOWS
SHOULD RANGE FROM THE UPPER 30S SOUTHWEST TO LOW TO MID 30S
NORTHEAST.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 215 PM WEDNESDAY...
HIGH CONFIDENCE IN RAIN ON THURSDAY...LOW CONFIDENCE IN AMOUNT.
MODELS ARE IN GOOD OVERALL AGREEMENT IN THE FORECAST OF THE CURRENT
MID-UPPER TROUGH CURRENTLY MOVING OUT OF TEXAS AND OKLAHOMA.
CONVECTION HAS BEEN BLOSSOMING OVER SE TEXAS THIS AFTERNOON. THIS
HAS BEEN HANDLED WELL THUS FAR BY THE 12Z GFS. ALL MODELS GENERALLY
SHOW THE MID-UPPER TROUGH PROGRESSING QUICKLY ENE TOWARD OUR REGION
TONIGHT AND THURSDAY. THE AFOREMENTIONED 12Z/GFS HAS PICKED UP ON
THE CONVECTION FLARING UP ALREADY OVER SE TEXAS... AND HAS THIS
CONVECTION SPREADING ENE ACROSS MS/AL AND GA OVERNIGHT THROUGH
12Z/THU. FROM THERE... MODELS DIVERGE ON POP/QPF OVER NC THURSDAY.
THE LATEST GFS AND NOW THE LATEST EUROPEAN MODELS DEPICT ALMOST
DOUBLE THE QPF OR RAINFALL AMOUNTS ACROSS MUCH OF OUR REGION THAN
THE 12Z/NAM WITH THE EVENT. YET... THE HIGH RESOLUTION MODELS IN
PARTICULAR THE SPC WRF AND THE HRRR DEPICT MINIMAL QPF OVER CENTRAL
NC. THIS LACK OF QPF MAY BE THE WAY TO GO GIVEN THE NCEP MODELS
TYPICAL FAILURE IN CAPTURING GULF COAST CONVECTION AND ITS ROLE IN
DISRUPTING MOISTURE TRANSPORT INTO THE CAROLINAS UPSTREAM.
HOWEVER... THE LATEST EURO SUPPORTS HEAVIER QPF ACROSS CENTRAL NC
WITH THE CONVECTION FALLING APART AS IT SWEEPS ACROSS THE DEEP SOUTH
LATE TONIGHT AND THURSDAY. WITH THIS IN MIND... WE WILL KEEP CURRENT
CATEGORICAL POP IN PLACE... AND CONTINUE TO FORECAST RAINFALL
AMOUNTS OF AROUND 0.25. IF CONVECTION DOES NOT SPREAD EAST ACROSS
GA... AND THE DEEP MOISTURE TRANSPORT (35-45KT SSW FLOW 925-850MB)
IN THE MODELS IS NOT DISRUPTED... THEN QPF OF UP TO A HALF INCH
WOULD BE LIKELY. HIGHS SHOULD SHOW QUITE A RANGE WITH SOME LIGHT
RAIN IN THE WEST EARLY... KEEPING HIGHS IN THE 50-55 RANGE. HIGHS
SHOULD REACH THE LOWER 60S AROUND FAY TO GSB.
THURSDAY NIGHT... SHOWERS WILL QUICKLY MOVE EAST WITH THE TROUGH...
BUT LOW LEVEL MOISTURE WILL LAG PER THE LATEST MODELS. DEPENDING ON
IF THE GROUND GETS WET OR NOT... FOG WILL/WILL NOT BE AN ISSUE. IF
WE SQUEEZE OUT 0.10 OR SO... THEN FOG WILL BE LIKELY. OTHERWISE...
PARTLY CLOUDY WITH LOWS 35-40.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
A DEAMPLIFYING SHORTWAVE PROGRESSING EAST THROUGH THE MID-ATLANTIC
ON THU (AND ITS ATTENDANT SFC LOW DEVELOPING OVER THE CAROLINAS)
WILL MOVE OFFSHORE THU NIGHT. EXPECT CLEAR SKIES EVERYWHERE BY 12Z
FRI MORNING AS DRY HIGH PRESSURE BUILDS INTO THE AREA FROM THE W/NW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE MID-ATLANTIC/CAROLINAS
FROM DURING THE DAY FRI...AND IS PROGGED TO BE CENTERED NEAR THE
MID-ATLANTIC COAST BY 12Z SAT. UNIFORM/FLAT FLOW ALOFT IS EXPECTED
OVER THE CAROLINAS FRI THROUGH FRI NIGHT. WITH THE ABOVE IN MIND...
EXPECT SUNNY SKIES DURING THE DAY FRI. 1000-850 MB THICKNESSES ARE
PROGGED TO RANGE FROM 1335-1345 METERS N-S ON FRIDAY...SUGGESTING
HIGHS RANGING FROM 59-65F OR SO...WARMEST NEAR THE SC BORDER. A LOW
PRESSURE SYSTEM IS EXPECTED TO BEGIN DEVELOPING IN VICINITY OF THE
TX GULF COAST LATE FRI NIGHT AS SHORTWAVE ENERGY CURRENTLY
PROGRESSING SOUTH THROUGH CA/NV AMPLIFIES INTO A CLOSED UPPER LOW
AND STARTS TRACKING EAST TOWARD WESTERN TX. IT IS POSSIBLE THAT SOME
UPPER LEVEL CLOUD COVER COULD MOVE INTO THE CAROLINAS DOWNSTREAM OF
PRECIPITATION EXPECTED ALONG THE GULF COAST STATES LATE FRI NIGHT...
HOWEVER...THE LATEST MODEL GUIDANCE INDICATES THAT MOST OF THE
INCREASE IN MID/UPPER LEVEL CLOUD COVER SHOULD HOLD OFF UNTIL AFTER
SUNRISE SAT (WHEN PRECIP IS EXPECTED TO BLOSSOM OVER THE DEEP
SOUTH)...WITH MINIMAL IMPACT ON LOW TEMPS. WILL FCST LOWS RANGING
FROM THE LOWER/MID 30S TO UPPER 30S SAT MORNING...COLDEST IN THE
TYPICAL SHELTERED/LOW-LYING AREAS...PARTICULARLY IN EAST/NE PORTIONS
OF THE AREA.
SATURDAY THROUGH SUNDAY NIGHT:
SIGNIFICANT UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF THE
AFOREMENTIONED STORM SYSTEM AS IT TRACKS FROM THE TX GULF COAST
THROUGH THE DEEP SOUTH AND INTO THE CAROLINAS/MID-ATLANTIC THIS
WEEKEND. THE OPERATIONAL MODELS ARE HAVING A VERY DIFFICULT TIME
DETERMINING HOW MUCH (IF ANY) PHASING WILL OCCUR BETWEEN THE
SHORTWAVE ENERGY EJECTING EASTWARD FROM TX INTO THE DEEP SOUTH
SAT/SAT NIGHT AND NORTHERN STREAM SHORTWAVE ENERGY DIVING SOUTHEAST
FROM WESTERN CANADA THROUGH THE UPPER MIDWEST/GREAT LAKES INTO THE
TN/OH VALLEYS. EXACTLY HOW THE NORTHERN/SOUTHERN STREAM SHORTWAVE
ENERGY INTERACTS WILL IN LARGE PART DETERMINE THE SUBSEQUENT
EVOLUTION OF THE LOW PRESSURE SYSTEM OVER AND OFFSHORE THE CAROLINAS
THIS WEEKEND. AT THIS TIME...THE ECMWF IS STILL THE PREFERRED MODEL
OF CHOICE GIVEN ITS CONSISTENCY AND BETTER TRACK RECORD...ALTHOUGH
CONSIDERABLE UNCERTAINTY PERSISTS EVEN WITH THE ECMWF DUE TO THE
COMPLEX NATURE OF THE UPPER LEVEL PATTERN AND THAT SOME OF THE KEY
FEATURES WILL NOT BE SAMPLED WELL BY THE RAOB NETWORK UNTIL LATER
THIS WEEK. WITH THE ABOVE IN MIND...ASIDE FROM INTRODUCING PRECIP
CHANCES FROM SW-NE SATURDAY AFTERNOON (A BIT EARLIER THAN PREVIOUSLY
INDICATED)...WILL MAKE FEW CHANGES TO THE CURRENT FORECAST FOR
SATURDAY THROUGH SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY:
THERE IS REASONABLE AGREEMENT AMONG THE LONG TERM MODELS THAT DRY
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS IN THE WAKE OF THE LOW
PRESSURE SYSTEM DEPARTING THE CAROLINA COAST SUN/SUN NIGHT...AND AT
THIS TIME EXPECT DRY CONDITIONS WITH SUNNY SKIES AND HIGHS NEAR
NORMAL IN THE LOWER/MID 50S...WITH LOWS MON NIGHT IN THE LOWER 30S.
UNCERTAINTY GROWS AGAIN BY MID-WEEK IN ADVANCE OF THE NEXT SYSTEM
EXPECTED TO APPROACH THE AREA FROM THE WEST LATE TUE NIGHT INTO WED.
AT THIS TIME...WILL KEEP THE FCST DRY ON TUE WITH HIGH PRESSURE
SLOWLY SHIFTING OFFSHORE THE CAROLINAS. A WARM/MOIST SOUTHERLY
RETURN FLOW IS PROGGED TO DEVELOP BY TUE NIGHT/WED AS HIGH PRESSURE
MOVES OFFSHORE IN ADVANCE OF THE NEXT SYSTEM PROGGED TO APPROACH THE
AREA BY MID-WEEK...AND WILL INTRODUCE A 30% CHANCE FOR SHOWERS ON
WED. -VINCENT
&&
.AVIATION /06Z THURSDAY THROUGH SUNDAY/...
AS OF 100 AM THURSDAY...
CURRENT VFR CONDITIONS ACROSS CENTRAL NC WILL DETERIORATE FROM WEST
TO EAST BY MIDDAY AS RAIN SPREADS EAST ACROSS THE AREA. THE
RAIN...AND ASSOCIATED LOW CEILINGS...APPEAR TO BE APPROACHING AS
MUCH AS 2 TO 3 HOURS FASTER THAN IN PREVIOUS FORECASTS. THERE
REMAINS SOME UNCERTAINTY AS TO HOW HEAVY THE RAIN WILL BE EAST OF
THE MOUNTAINS...BUT THERE IS STILL GOOD CONFIDENCE THAT CEILINGS
WILL FALL TO IFR BY 15Z AT KGSO/KINT...AND BY 18Z TO 20Z AT
KRDU/KFAY/KRWI. WHERE RAIN IS HEAVIER...LIFR CEILINGS AND IFR VSBYS
WILL BE POSSIBLE. SOUTHEASTERLY SURFACE WINDS ARE NOT EXPECTED TO
BE VERY STRONG OR GUSTY...BUT IF ANY GUSTS DO DEVELOP IT WOULD BE
MORE LIKELY AT KFAY AS A WARM FRONT LIFTS INTO EASTERN. WINDS WILL
THEN TURN TO WEST-NORTHWESTERLY AFTER 00Z AS DRIER AIR FILTERS INTO
THE AREA AND SKIES BEGIN TO CLEAR. SOME FOG MAY BE POSSIBLE AFTER
06Z FRIDAY.
OUTLOOK...
THE FOG IS EXPECTED TO LIFT EARLY FRIDAY...WITH VFR
CONDITIONS RETURNING BY 15Z FRIDAY MORNING. THERE IS AN INCREASING
CHANCE OF WIDESPREAD RAIN WITH IFR CIGS/VSBYS AS ANOTHER SYSTEM
APPROACHES OUR REGION THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...SMITH
SHORT TERM...BADGETT
LONG TERM...VINCENT
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 AM EST THU FEB 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST AND OFFSHORE THIS MORNING. A WEAK
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
REGION THURSDAY AFTERNOON AND EVENING.
&&
.NEAR TERM /TONIGHT/...
AS OF 910 PM WEDNESDAY...
A DRY AIRMASS IS IN PLACE THIS EVENING ACROSS CENTRAL NC
AS A 1026 MB SURFACE HIGH WAS CENTERED OVER THE REGION.
THICKENING WAA MID/UPPER LEVEL CLOUD CANOPY ASSOCIATED WITH
A DAMPENING WAVE OVER MISSOURI HAS ALREADY ADVANCED EASTWARD
ACROSS WESTERN HALF OF THE STATE....AND WILL CONTINUE TO SPREAD EAST
OVERNIGHT AS THE WAVE REACHES THE OHIO VALLEY/LOWER GREAT LAKES BY
THURSDAY MORNING. HOWEVER ANY MEASURABLE RAIN SHOULD HOLD OFF UNTIL
AFTER DAYBREAK AS THE ANTECEDENT DRY LOW-LEVEL AIRMASS(CHARACTERIZED
BY SFC DEWPOINTS IN THE 25 TO 35F RANGE)WILL UNDERGO ONLY SLIGHT
MODERATION AS SURFACE HIGH SHIFTS OFFSHORE LATE.
BASED ON LATEST SATELLITE AND OBSERVATIONS TRENDS...RADIATIONAL
COOLING HAS ALREADY CEASED ACROSS THE WESTERN PIEDMONT...WITH
ANOTHER 2 TO 3 HOURS OF COOLING IN THE EAST BEFORE IT IS MET WITH
THE SAME FATE. FORECAST MINS TONIGHT LOOK A GOOD 4 TO 7 DEGREES TOO
COOL IN THE WEST...2 TO 4 DEGREES TOO WARM ACROSS CENTRAL AREAS.
NORTHERN COASTAL PLAIN COUNTIES COULD STILL POTENTIALLY REACH
PROJECTED LOWS OF UPPER 30S IN THE NEXT COUPLE OF HOUR.
OVERNIGHT LOWS FROM NEAR 50 WEST TO UPPER 30S NORTHEAST.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 215 PM WEDNESDAY...
HIGH CONFIDENCE IN RAIN ON THURSDAY...LOW CONFIDENCE IN AMOUNT.
MODELS ARE IN GOOD OVERALL AGREEMENT IN THE FORECAST OF THE CURRENT
MID-UPPER TROUGH CURRENTLY MOVING OUT OF TEXAS AND OKLAHOMA.
CONVECTION HAS BEEN BLOSSOMING OVER SE TEXAS THIS AFTERNOON. THIS
HAS BEEN HANDLED WELL THUS FAR BY THE 12Z GFS. ALL MODELS GENERALLY
SHOW THE MID-UPPER TROUGH PROGRESSING QUICKLY ENE TOWARD OUR REGION
TONIGHT AND THURSDAY. THE AFOREMENTIONED 12Z/GFS HAS PICKED UP ON
THE CONVECTION FLARING UP ALREADY OVER SE TEXAS... AND HAS THIS
CONVECTION SPREADING ENE ACROSS MS/AL AND GA OVERNIGHT THROUGH
12Z/THU. FROM THERE... MODELS DIVERGE ON POP/QPF OVER NC THURSDAY.
THE LATEST GFS AND NOW THE LATEST EUROPEAN MODELS DEPICT ALMOST
DOUBLE THE QPF OR RAINFALL AMOUNTS ACROSS MUCH OF OUR REGION THAN
THE 12Z/NAM WITH THE EVENT. YET... THE HIGH RESOLUTION MODELS IN
PARTICULAR THE SPC WRF AND THE HRRR DEPICT MINIMAL QPF OVER CENTRAL
NC. THIS LACK OF QPF MAY BE THE WAY TO GO GIVEN THE NCEP MODELS
TYPICAL FAILURE IN CAPTURING GULF COAST CONVECTION AND ITS ROLE IN
DISRUPTING MOISTURE TRANSPORT INTO THE CAROLINAS UPSTREAM.
HOWEVER... THE LATEST EURO SUPPORTS HEAVIER QPF ACROSS CENTRAL NC
WITH THE CONVECTION FALLING APART AS IT SWEEPS ACROSS THE DEEP SOUTH
LATE TONIGHT AND THURSDAY. WITH THIS IN MIND... WE WILL KEEP CURRENT
CATEGORICAL POP IN PLACE... AND CONTINUE TO FORECAST RAINFALL
AMOUNTS OF AROUND 0.25. IF CONVECTION DOES NOT SPREAD EAST ACROSS
GA... AND THE DEEP MOISTURE TRANSPORT (35-45KT SSW FLOW 925-850MB)
IN THE MODELS IS NOT DISRUPTED... THEN QPF OF UP TO A HALF INCH
WOULD BE LIKELY. HIGHS SHOULD SHOW QUITE A RANGE WITH SOME LIGHT
RAIN IN THE WEST EARLY... KEEPING HIGHS IN THE 50-55 RANGE. HIGHS
SHOULD REACH THE LOWER 60S AROUND FAY TO GSB.
THURSDAY NIGHT... SHOWERS WILL QUICKLY MOVE EAST WITH THE TROUGH...
BUT LOW LEVEL MOISTURE WILL LAG PER THE LATEST MODELS. DEPENDING ON
IF THE GROUND GETS WET OR NOT... FOG WILL/WILL NOT BE AN ISSUE. IF
WE SQUEEZE OUT 0.10 OR SO... THEN FOG WILL BE LIKELY. OTHERWISE...
PARTLY CLOUDY WITH LOWS 35-40.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
A DEAMPLIFYING SHORTWAVE PROGRESSING EAST THROUGH THE MID-ATLANTIC
ON THU (AND ITS ATTENDANT SFC LOW DEVELOPING OVER THE CAROLINAS)
WILL MOVE OFFSHORE THU NIGHT. EXPECT CLEAR SKIES EVERYWHERE BY 12Z
FRI MORNING AS DRY HIGH PRESSURE BUILDS INTO THE AREA FROM THE W/NW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE MID-ATLANTIC/CAROLINAS
FROM DURING THE DAY FRI...AND IS PROGGED TO BE CENTERED NEAR THE
MID-ATLANTIC COAST BY 12Z SAT. UNIFORM/FLAT FLOW ALOFT IS EXPECTED
OVER THE CAROLINAS FRI THROUGH FRI NIGHT. WITH THE ABOVE IN MIND...
EXPECT SUNNY SKIES DURING THE DAY FRI. 1000-850 MB THICKNESSES ARE
PROGGED TO RANGE FROM 1335-1345 METERS N-S ON FRIDAY...SUGGESTING
HIGHS RANGING FROM 59-65F OR SO...WARMEST NEAR THE SC BORDER. A LOW
PRESSURE SYSTEM IS EXPECTED TO BEGIN DEVELOPING IN VICINITY OF THE
TX GULF COAST LATE FRI NIGHT AS SHORTWAVE ENERGY CURRENTLY
PROGRESSING SOUTH THROUGH CA/NV AMPLIFIES INTO A CLOSED UPPER LOW
AND STARTS TRACKING EAST TOWARD WESTERN TX. IT IS POSSIBLE THAT SOME
UPPER LEVEL CLOUD COVER COULD MOVE INTO THE CAROLINAS DOWNSTREAM OF
PRECIPITATION EXPECTED ALONG THE GULF COAST STATES LATE FRI NIGHT...
HOWEVER...THE LATEST MODEL GUIDANCE INDICATES THAT MOST OF THE
INCREASE IN MID/UPPER LEVEL CLOUD COVER SHOULD HOLD OFF UNTIL AFTER
SUNRISE SAT (WHEN PRECIP IS EXPECTED TO BLOSSOM OVER THE DEEP
SOUTH)...WITH MINIMAL IMPACT ON LOW TEMPS. WILL FCST LOWS RANGING
FROM THE LOWER/MID 30S TO UPPER 30S SAT MORNING...COLDEST IN THE
TYPICAL SHELTERED/LOW-LYING AREAS...PARTICULARLY IN EAST/NE PORTIONS
OF THE AREA.
SATURDAY THROUGH SUNDAY NIGHT:
SIGNIFICANT UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF THE
AFOREMENTIONED STORM SYSTEM AS IT TRACKS FROM THE TX GULF COAST
THROUGH THE DEEP SOUTH AND INTO THE CAROLINAS/MID-ATLANTIC THIS
WEEKEND. THE OPERATIONAL MODELS ARE HAVING A VERY DIFFICULT TIME
DETERMINING HOW MUCH (IF ANY) PHASING WILL OCCUR BETWEEN THE
SHORTWAVE ENERGY EJECTING EASTWARD FROM TX INTO THE DEEP SOUTH
SAT/SAT NIGHT AND NORTHERN STREAM SHORTWAVE ENERGY DIVING SOUTHEAST
FROM WESTERN CANADA THROUGH THE UPPER MIDWEST/GREAT LAKES INTO THE
TN/OH VALLEYS. EXACTLY HOW THE NORTHERN/SOUTHERN STREAM SHORTWAVE
ENERGY INTERACTS WILL IN LARGE PART DETERMINE THE SUBSEQUENT
EVOLUTION OF THE LOW PRESSURE SYSTEM OVER AND OFFSHORE THE CAROLINAS
THIS WEEKEND. AT THIS TIME...THE ECMWF IS STILL THE PREFERRED MODEL
OF CHOICE GIVEN ITS CONSISTENCY AND BETTER TRACK RECORD...ALTHOUGH
CONSIDERABLE UNCERTAINTY PERSISTS EVEN WITH THE ECMWF DUE TO THE
COMPLEX NATURE OF THE UPPER LEVEL PATTERN AND THAT SOME OF THE KEY
FEATURES WILL NOT BE SAMPLED WELL BY THE RAOB NETWORK UNTIL LATER
THIS WEEK. WITH THE ABOVE IN MIND...ASIDE FROM INTRODUCING PRECIP
CHANCES FROM SW-NE SATURDAY AFTERNOON (A BIT EARLIER THAN PREVIOUSLY
INDICATED)...WILL MAKE FEW CHANGES TO THE CURRENT FORECAST FOR
SATURDAY THROUGH SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY:
THERE IS REASONABLE AGREEMENT AMONG THE LONG TERM MODELS THAT DRY
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS IN THE WAKE OF THE LOW
PRESSURE SYSTEM DEPARTING THE CAROLINA COAST SUN/SUN NIGHT...AND AT
THIS TIME EXPECT DRY CONDITIONS WITH SUNNY SKIES AND HIGHS NEAR
NORMAL IN THE LOWER/MID 50S...WITH LOWS MON NIGHT IN THE LOWER 30S.
UNCERTAINTY GROWS AGAIN BY MID-WEEK IN ADVANCE OF THE NEXT SYSTEM
EXPECTED TO APPROACH THE AREA FROM THE WEST LATE TUE NIGHT INTO WED.
AT THIS TIME...WILL KEEP THE FCST DRY ON TUE WITH HIGH PRESSURE
SLOWLY SHIFTING OFFSHORE THE CAROLINAS. A WARM/MOIST SOUTHERLY
RETURN FLOW IS PROGGED TO DEVELOP BY TUE NIGHT/WED AS HIGH PRESSURE
MOVES OFFSHORE IN ADVANCE OF THE NEXT SYSTEM PROGGED TO APPROACH THE
AREA BY MID-WEEK...AND WILL INTRODUCE A 30% CHANCE FOR SHOWERS ON
WED. -VINCENT
&&
.AVIATION /06Z THURSDAY THROUGH SUNDAY/...
AS OF 100 AM THURSDAY...
CURRENT VFR CONDITIONS ACROSS CENTRAL NC WILL DETERIORATE FROM WEST
TO EAST BY MIDDAY AS RAIN SPREADS EAST ACROSS THE AREA. THE
RAIN...AND ASSOCIATED LOW CEILINGS...APPEAR TO BE APPROACHING AS
MUCH AS 2 TO 3 HOURS FASTER THAN IN PREVIOUS FORECASTS. THERE
REMAINS SOME UNCERTAINTY AS TO HOW HEAVY THE RAIN WILL BE EAST OF
THE MOUNTAINS...BUT THERE IS STILL GOOD CONFIDENCE THAT CEILINGS
WILL FALL TO IFR BY 15Z AT KGSO/KINT...AND BY 18Z TO 20Z AT
KRDU/KFAY/KRWI. WHERE RAIN IS HEAVIER...LIFR CEILINGS AND IFR VSBYS
WILL BE POSSIBLE. SOUTHEASTERLY SURFACE WINDS ARE NOT EXPECTED TO
BE VERY STRONG OR GUSTY...BUT IF ANY GUSTS DO DEVELOP IT WOULD BE
MORE LIKELY AT KFAY AS A WARM FRONT LIFTS INTO EASTERN. WINDS WILL
THEN TURN TO WEST-NORTHWESTERLY AFTER 00Z AS DRIER AIR FILTERS INTO
THE AREA AND SKIES BEGIN TO CLEAR. SOME FOG MAY BE POSSIBLE AFTER
06Z FRIDAY.
OUTLOOK...
THE FOG IS EXPECTED TO LIFT EARLY FRIDAY...WITH VFR
CONDITIONS RETURNING BY 15Z FRIDAY MORNING. THERE IS AN INCREASING
CHANCE OF WIDESPREAD RAIN WITH IFR CIGS/VSBYS AS ANOTHER SYSTEM
APPROACHES OUR REGION THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...CBL
SHORT TERM...BADGETT
LONG TERM...VINCENT
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
113 AM EST THU FEB 16 2012
.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT WILL BRING RAIN TO THE REGION LATE
TONIGHT AND THROUGH MID DAY THURSDAY. HIGH PRESSURE WILL THEN
BUILD IN THROUGH FRIDAY. ANOTHER COLD FRONT WILL MOVE THROUGH ON
SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
ONE BAND OF SHOWERS WILL CONTINUE TO AFFECT THE NORTHERN CWA OVER
THE NEXT HOUR OR TWO. ANOTHER AREA OF LIGHT TO MODERATE SHOWERS
IS CURRENTLY DEVELOPING OVER SOUTHERN INDIANA AND NORTHERN
KENTUCKY ON THE NOSE OF A LOW LEVEL JET. LATEST RUC SHOWS THIS
JET INTENSIFYING A BIT AS IT PIVOTS INTO THE SOUTHWESTERN PORTION
OF CWA BY 09Z. IT THEN WEAKENS AS IT MEANDERS NORTHEAST INTO
CENTRAL OHIO BY DAYBREAK. EXPECT SHOWERS TO BECOME STEADIER LATE
TONIGHT AS THE JET DEVELOPS AND MOVES ACROSS THE CWA...AND AS LOW
PRESSURE AND ASSOCIATED COLD FRONT APPROACH FROM THE SOUTHWEST.
MODELS IN GOOD AGREEMENT WITH SHOWERS TAPERING OFF FAIRLY QUICKLY
FROM WEST TO EAST WITH FRONTAL PASSAGE BY LATE THURSDAY MORNING.
ADJUSTED TONIGHT/S TEMPERATURES JUST SLIGHTLY BASED ON CURRENT
TRENDS. WILL SEE SOME RISE IN TEMPS DURING THE AFTERNOON
ESPECIALLY AS CLOUDS START BREAKING UP. BUT WENT SLIGHTLY BELOW
GUIDANCE FOR HIGHS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL MOVE ACROSS THE REGION THROUGH THE PERIOD.
EXPECT LITTLE IN THE WAY OF CLOUD COVER UNTIL POSSIBLY LATE FRIDAY
NIGHT WITH THE APPROACH OF THE NEXT SYSTEM. STAYED CLOSE TO MOS
CONSENSUS FOR LOWS BUT WENT SLIGHTLY COOLER FOR HIGHS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS DISAGREE FOR THE SATURDAY THROUGH SATURDAY NIGHT TIME FRAME.
BOTH THE GFS AND THE ECMWF HAVE A SOUTHERN SYSTEM AND A NORTHERN
SYSTEM. THE ECMWF KEEPS THESE SYSTEMS SEPARATE WHILE THE GFS TRIES
TO PHASE THESE TWO FEATURES AND THEREFORE BRINGS PRECIPITATION INTO
THE AREA. WENT CLOSER TO THE ECMWF SOLUTION HOWEVER DID NOT WANT TO
TOTALLY DISCOUNT THE GFS AT THIS POINT IN TIME. DUE TO
THIS...LIMITED PRECIPITATION CHANCES TO A CHANCE ON SATURDAY AND A
SLIGHT CHANCE SATURDAY NIGHT. PRECIPITATION WILL TAPER OFF SATURDAY
NIGHT.
DRIER AND COOLER CONDITIONS WILL BE PRESENT ACROSS THE FA FOR
SUNDAY. SKIES WILL BE MOSTLY CLEAR SUNDAY NIGHT WITH HIGH PRESSURE
ACROSS THE AREA. WITH LIGHT WINDS AND CLEAR SKIES DROPPED
TEMPERATURES DOWN INTO THE LOWER 20S. SOUTHERLY FLOW WILL ALLOW FOR
TEMPERATURES TO WARM DURING THE DAY ON MONDAY INTO THE 40S.
THE NEXT SYSTEM WILL BEGIN TO BRING RAIN TO THE AREA TUESDAY
AFTERNOON. BETTER RAIN CHANCES WILL OCCUR TUESDAY NIGHT INTO
WEDNESDAY AS THE AREA OF LOW PRESSURE NEARS THE FA.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
INITIAL WAVE OF SHRA IS PUSHING THRU THE TAFS ON AREA OF ISENTROPIC
LIFT. CIGS WITH THIS INITIAL SHOT ARE STILL VFR ALONG WITH MOST
OF THE VSBYS. THINK SOME OF THE SHOWERS COULD PRODUCE MVFR VSBYS
SO HAVE A TEMPO 4SM SHRA. THE WAVE PUSHES THRU THE SRN TAFS BY
08Z.
SCT LIGHT SHRA IS DEVELOPING OVER INDIANA AHEAD OF LOW PRESSURE
AREA. CIGS AND VSBYS WILL DROP TO MVFR AS LOW CROSSES THE TAFS
IN THE 11-15Z TIME FRAME. MVFR CIGS TO PERSIST IN LINGERING LOW
LEVEL MOISTURE BEHIND THE FRONT.
LOW CLOUDS WILL SCATTER OUT AROUND 21Z IN THE W. MODEL TIME
SERIES ARE SHOWING POSSIBLE STRATUS DEVELOPMENT AFT 03Z. INCLUDED
IFR ST ALONG WITH MVFR VSBYS.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KURZ
SHORT TERM...
LONG TERM...NOVAK
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
155 AM EST THU FEB 16 2012
.SYNOPSIS...
A FRONTAL SYSTEM MOVING FROM THE OHIO VALLEY THROUGH PENNSYLVANIA
WILL BRING WIDESPREAD LIGHT PRECIPITATION TO THE REGION TODAY. THE
LIGHT PRECIPITATION WILL START AS A WINTRY MIX IN SOME LOCATIONS
BEFORE TRANSITIONING TO RAIN BY THE LATE MORNING AND EARLY
AFTERNOON. HIGH PRESSURE WILL RETURN ON FRIDAY AND PROVIDE A DRY
START TO THE WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
REGIONAL RADAR SHOWS WARM ADV PCPN PUSHING EWD THRU THE UPPER OH
VLY AND APPROACHING NW PA AS OF 06Z. RUC SFC-850MB THERMAL
PROFILES INDICATE A MARGINALLY WARM +1-2C LAYER AT 925MB. P TYPES
COULD GO EITHER WAY DEPENDING ON PCPN RATES/WET BULB EFFECTS AND SUB-
FZG SFC TEMPS. THEREFORE WILL MENTION A MIXED BAG OF WINTRY PCPN
BEFORE SUNRISE MAINLY OVER THE N-CNTRL MTNS. WILL CONTINUE TO
MONITOR FOR POSSIBLE FZRA ADVY.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
A NRN STREAM TROF CROSSING THE UPPER GREAT LAKES SHOULD GRADUALLY
PHASE WITH THE LEAD WAVE IN THE SRN STREAM AS THEY ENTER THE NERN
QUAD OF THE COUNTRY ON THURS...RESULTING IN A PAIR OF WEAK SFC
LOWS INVOF THE GREAT LKS SLOWLY DEEPENING AND CONSOLIDATING INTO
ONE PRIMARY LOW CENTER IN SERN CANADA BY THURS NGT.
MEANWHILE...HEIGHT FALLS SPREADING ACRS THE MID-ATLANTIC REGION
SHOULD INDUCE A SECONDARY LOW NEAR THE CAROLINA COAST ALONG THE
ATTENDANT COLD FRONT TRAILING SWD FROM THE PRIMARY LOW. A SURGE OF
ABOVE NORMAL PWATS AND FAVORABLE JET DYNAMICS WILL ACCOMPANY THIS
SYSTEM AND SUPPORT WIDESPREAD PRECIPITATION ACRS CENTRAL PA THIS
PERIOD.
THE MAIN CONCERN AND GREATEST UNCERTAINTY IN THE SHORT TERM FCST
INVOLVES TRANSITIONING P TYPES...AS RELATIVELY WARM AIR ALOFT
/ABOVE 0C AIR AT 850MB/ IS COOLED FROM THE TOP DOWN DUE TO WET-
BULB EFFECTS AND LLVL MESOSCALE COLD AIR DAMMING PROCESSES KEEP
SFC TEMPS NEAR THE FREEZING MARK. FCST MODEL SOUNDINGS AND PLUME
DIAGRAMS STILL INDICATE THE POTENTIAL FOR A MIXED BAG OF WINTRY
PRECIP BEFORE GOING OVER TO MAINLY RAIN LATER THURS. DESPITE THE
P TYPE UNCERTAINTY...MARGINAL BLYR TEMPS AND TIME OF DAY WILL BE
LIMITING FACTORS FOR SNOW/ICE ACCUMULATIONS.
A SURGE OF COLDER AIR WILL INVADE THE REGION IN THE WAKE OF THE
COLD FROPA LATER THURS NIGHT INTO EARLY FRI...WITH PLENTY OF POST-
FRONTAL LOW CLOUDS/STRATOCU AND OCNL LAKE EFFECT/UPSLOPE SNOW
SHOWERS FOCUSED OVR THE HIGHER TERRAIN OF THE WESTERN ALLEGHENIES.
MAIN CHANGE FROM RECENT DAYS WILL BE THE AMT OF COLD AIR THAT
FOLLOWS THE MAIN SYSTEM LATE THU...WILL ADDITIONAL SYSTEMS
PULL IN A LOT OF COLD AIR AFTER THU...SEE SECTION BELOW.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WAVE EXITING TO THE EAST THU NIGHT WILL CHANGE LINGERING SHOWERS
OVER TO SNOW SHOWERS BEFORE ENDING AS MEAN FLOW AGAIN BECOMES
ZONAL. COLDER AIR...SEASONAL AIR...FILTERS IN BEHIND FOR
FRI AS HIGH PRESSURE SLIDES IN...WITH HIGHS ABOUT 10F LOWER THAN
THU - PUTTING THEM CLOSE TO NORMALS.
A RATHER FLAT...NRN STREAM SHORT WAVE SLIDES BY JUST TO THE NORTH
ON SATURDAY AND MAY TRIGGER A FEW RAIN OR WET SNOW SHOWERS OVR THE
NRN MTNS. THIS FEATURE WILL SHOULD PUSH A SECONDARY COLD FRONT
SEWD ACROSS THE COMMONWEALTH...ALLOWING A REINFORCING/SLIGHTLY
COLDER AIR MASS TO SPREAD INTO THE AREA FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY NEXT WEEK.
LOTS OF DIVERGENCE IN MODEL SOLUTIONS ON SUNDAY...WITH GFS MOST
INTERESTINGLY PRODUCING THE MOST PHASING WITH NORTHERN STREAM
ALONG WITH A DEEPENING LOW OFF THE MID ATLANTIC COAST. OTHER
MODELS AREN/T AS AGGRESSIVE...SHUNTING THE LOW FURTHER SOUTH AND
EAST AS RIDGE OF HIGH PRESSURE EDGES IN FROM THE NW. DID ADJUST
POPS UPWARD 10-20 PERCENT FOR SAT NIGHT/SUNDAY THOUGH...AND WILL
BE INTERESTING TO SEE IF ANY OTHER MODELS ADOPT THE GFS SOLUTION.
RIDGE DOES BECOME THE DOMINANT FEATURE MON INTO TUE WITH COOL
MORNING AND MODERATING MAXES...AS RETURN FLOW KICKS IN ON TUE.
ANOTHER SYSTEM PROGGED FOR WED WITH A MIX OF RAIN/SNOW AS TEMPS
REMAIN ABOVE NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE WILL TRACK EAST ACROSS THE OHIO VALLEY THIS
MORNING...SPREADING LOWERING CLOUDS ACROSS CENTRAL PA. LEADING
EDGE OF SPOTTY...LIGHT PRECIP JUST ENTERING WESTERN PA AT 06Z AND
SHOULD REACH MUCH OF CENTRAL PA BTWN 08Z-12Z. TEMPS WILL LIKELY BE
JUST COLD ENOUGH TO SUPPORT A LIGHT WINTRY MIX ACROSS THE NORTHERN
HALF OF THE STATE WITH THIS FIRST BATCH OF PRECIP...WHILE -SHRA
MOST LIKELY ACROSS THE SOUTH. A DRY LAYER IN THE ATMOSPHERE BLW
3KM /AS EVIDENCED BY 00Z PIT SOUNDING/ WILL LIKELY KEEP CIGS/VSBYS
IN THE VFR RANGE THRU AT LEAST DAWN.
AS LOW PRESSURE APPROACHES...DETERIORATING CIGS/VSBYS EXPECTED
DURING THE DAYLIGHT HOURS. ANY EARLY AM WINTRY MIX OVR NORTHERN PA
SHOULD TURN TO -RA BY MIDDAY...BUT WIDESPREAD IFR CONDS APPEAR
LIKELY BY AFTN OVR THE CENTRAL AND WESTERN MTNS AS STEADIER RAIN
ARRIVES. MARGINALLY HIGHER CIGS/VSBYS ARE POSSIBLE ACROSS THE
LOWER ELEVATIONS OF THE SUSQ VALLEY INCLUDING IPT/MDT/LNS.
RAIN WILL TAPER OFF THIS EVENING. HOWEVER...RESIDUAL LOW LVL
MOISTURE AND A LGT WIND WILL LIKELY RESULT IN AREAS OF FOG. A
DRIER WESTERLY FLOW WILL DEVELOP LATE TONIGHT...AS THE LOW PRES
SYS PASSES EAST OF PA. THIS WILL BRING A RETURN TO VFR CONDS EAST
OF THE MTNS. HOWEVER...UPSLOPING FLOW COULD PRODUCE LINGERING MVFR
CIGS AT BFD/JST.
OUTLOOK...
FRI...AM LOW CIGS POSS W MTNS.
SAT...NO SIG WX EXPECTED.
SUN...SNOW/LOW VSBYS POSSIBLE SOUTHERN PA.
MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN/STEINBUGL
NEAR TERM...DEVOIR/STEINBUGL
SHORT TERM...MARTIN/STEINBUGL
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
119 AM EST THU FEB 16 2012
.SYNOPSIS...
A FRONTAL SYSTEM MOVING FROM THE OHIO VALLEY THROUGH PENNSYLVANIA
WILL BRING WIDESPREAD LIGHT PRECIPITATION TO THE REGION TODAY. THE
LIGHT PRECIPITATION WILL START AS A WINTRY MIX IN SOME LOCATIONS
BEFORE TRANSITIONING TO RAIN BY THE LATE MORNING AND EARLY
AFTERNOON. HIGH PRESSURE WILL RETURN ON FRIDAY AND PROVIDE A DRY
START TO THE WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
REGIONAL RADAR SHOWS WARM ADV PCPN PUSHING EWD THRU THE UPPER OH
VLY AND APPROACHING NW PA AS OF 06Z. RUC SFC-850MB THERMAL
PROFILES INDICATE A MARGINALLY WARM +1-2C LAYER AT 925MB. P TYPES
COULD GO EITHER WAY DEPENDING ON PCPN RATES/WET BULB EFFECTS AND SUB-
FZG SFC TEMPS. THEREFORE WILL MENTION A MIXED BAG OF WINTRY PCPN
BEFORE SUNRISE MAINLY OVER THE N-CNTRL MTNS. WILL CONTINUE TO
MONITOR FOR POSSIBLE FZRA ADVY.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
A NRN STREAM TROF CROSSING THE UPPER GREAT LAKES SHOULD GRADUALLY
PHASE WITH THE LEAD WAVE IN THE SRN STREAM AS THEY ENTER THE NERN
QUAD OF THE COUNTRY ON THURS...RESULTING IN A PAIR OF WEAK SFC
LOWS INVOF THE GREAT LKS SLOWLY DEEPENING AND CONSOLIDATING INTO
ONE PRIMARY LOW CENTER IN SERN CANADA BY THURS NGT.
MEANWHILE...HEIGHT FALLS SPREADING ACRS THE MID-ATLANTIC REGION
SHOULD INDUCE A SECONDARY LOW NEAR THE CAROLINA COAST ALONG THE
ATTENDANT COLD FRONT TRAILING SWD FROM THE PRIMARY LOW. A SURGE OF
ABOVE NORMAL PWATS AND FAVORABLE JET DYNAMICS WILL ACCOMPANY THIS
SYSTEM AND SUPPORT WIDESPREAD PRECIPITATION ACRS CENTRAL PA THIS
PERIOD.
THE MAIN CONCERN AND GREATEST UNCERTAINTY IN THE SHORT TERM FCST
INVOLVES TRANSITIONING P TYPES...AS RELATIVELY WARM AIR ALOFT
/ABOVE 0C AIR AT 850MB/ IS COOLED FROM THE TOP DOWN DUE TO WET-
BULB EFFECTS AND LLVL MESOSCALE COLD AIR DAMMING PROCESSES KEEP
SFC TEMPS NEAR THE FREEZING MARK. FCST MODEL SOUNDINGS AND PLUME
DIAGRAMS STILL INDICATE THE POTENTIAL FOR A MIXED BAG OF WINTRY
PRECIP BEFORE GOING OVER TO MAINLY RAIN LATER THURS. DESPITE THE
P TYPE UNCERTAINTY...MARGINAL BLYR TEMPS AND TIME OF DAY WILL BE
LIMITING FACTORS FOR SNOW/ICE ACCUMULATIONS.
A SURGE OF COLDER AIR WILL INVADE THE REGION IN THE WAKE OF THE
COLD FROPA LATER THURS NIGHT INTO EARLY FRI...WITH PLENTY OF POST-
FRONTAL LOW CLOUDS/STRATOCU AND OCNL LAKE EFFECT/UPSLOPE SNOW
SHOWERS FOCUSED OVR THE HIGHER TERRAIN OF THE WESTERN ALLEGHENIES.
MAIN CHANGE FROM RECENT DAYS WILL BE THE AMT OF COLD AIR THAT
FOLLOWS THE MAIN SYSTEM LATE THU...WILL ADDITIONAL SYSTEMS
PULL IN A LOT OF COLD AIR AFTER THU...SEE SECTION BELOW.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WAVE EXITING TO THE EAST THU NIGHT WILL CHANGE LINGERING SHOWERS
OVER TO SNOW SHOWERS BEFORE ENDING AS MEAN FLOW AGAIN BECOMES
ZONAL. COLDER AIR...SEASONAL AIR...FILTERS IN BEHIND FOR
FRI AS HIGH PRESSURE SLIDES IN...WITH HIGHS ABOUT 10F LOWER THAN
THU - PUTTING THEM CLOSE TO NORMALS.
A RATHER FLAT...NRN STREAM SHORT WAVE SLIDES BY JUST TO THE NORTH
ON SATURDAY AND MAY TRIGGER A FEW RAIN OR WET SNOW SHOWERS OVR THE
NRN MTNS. THIS FEATURE WILL SHOULD PUSH A SECONDARY COLD FRONT
SEWD ACROSS THE COMMONWEALTH...ALLOWING A REINFORCING/SLIGHTLY
COLDER AIR MASS TO SPREAD INTO THE AREA FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY NEXT WEEK.
LOTS OF DIVERGENCE IN MODEL SOLUTIONS ON SUNDAY...WITH GFS MOST
INTERESTINGLY PRODUCING THE MOST PHASING WITH NORTHERN STREAM
ALONG WITH A DEEPENING LOW OFF THE MID ATLANTIC COAST. OTHER
MODELS AREN/T AS AGGRESSIVE...SHUNTING THE LOW FURTHER SOUTH AND
EAST AS RIDGE OF HIGH PRESSURE EDGES IN FROM THE NW. DID ADJUST
POPS UPWARD 10-20 PERCENT FOR SAT NIGHT/SUNDAY THOUGH...AND WILL
BE INTERESTING TO SEE IF ANY OTHER MODELS ADOPT THE GFS SOLUTION.
RIDGE DOES BECOME THE DOMINANT FEATURE MON INTO TUE WITH COOL
MORNING AND MODERATING MAXES...AS RETURN FLOW KICKS IN ON TUE.
ANOTHER SYSTEM PROGGED FOR WED WITH A MIX OF RAIN/SNOW AS TEMPS
REMAIN ABOVE NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
MID AND HIGH CLOUDS CONTINUE TO FLOOD INTO THE REGION. ALL SITES
HAVE GONE VFR WITH THE EXCEPTION OF A BIT OF THIN FOG AT AOO. I
DON`T EXPECT THE FOG TO BECOME A BIG PROBLEM AS THE CLOUDS
CONTINUE TO LOWER AND THICKEN OVERNIGHT...SHUTTING OFF THE RAD
COOLING.
CONDITIONS WILL DETERIORATE AGAIN THURS WITH THE APPROACH OF THE
NEXT SYSTEM. MOST OF THE PCPN WILL MOVE IN AROUND OR SHORTLY
AFTER SUNRISE. TEMPS MAY BE COLD ENOUGH TO SUPPORT SOME FREEZING
RAIN OR WET SNOW EARLY...BUT EXPECT THINGS TO WARM UP FAST AS A
COMPLEX FRONTAL SYSTEM SWEEPS ACROSS THE REGION.
WILL HOLD ONTO THE NO SIG WX OUTLOOK FOR THE WEEKEND...BUT THERE
REMAINS SOME SPREAD IN MODEL SOLUTIONS. NEW OPERATIONAL NAM TAKES
A STRONG LOW OUT JUST SOUTH OF THE REGION WHILE THE 18Z GFS MADE A
SNOW STORM SUNDAY. STAY TUNED.
OUTLOOK...
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN/STEINBUGL
NEAR TERM...DEVOIR/STEINBUGL
SHORT TERM...MARTIN/STEINBUGL
LONG TERM...RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1124 PM CST WED FEB 15 2012
.AVIATION...
TOUGH AVIATION FORECAST TONIGHT REGARDING THE POTENTIAL MVFR/IFR
CIGS REACHING THE METROPLEX. CURRENT SATELLITE SHOWS THE CIGS
OVER OKLAHOMA CITY AND MOVING SOUTH. LATEST SHORT-TERM MODEL
GUIDANCE CONTINUES TO SHOW THIS SOUTHWARD PROGRESSION INTO THE
METRO BUT HAVE SLOWED DOWN THE TIMING A BIT. THE HRRR SEEMS TO
HAVE TROUBLE HANDLING THE DENSE FOG/VLIFR CIGS TO THE EAST AND
BRINGS THEM INTO ALL SITES BY MORNING DESPITE BREEZY NORTHWESTERLY
FLOW. THE RUC/NAM DONT SUPPORT THIS SOLUTION AND THINK THAT IS
BEST. WILL PUSH THE ARRIVAL OF THE MVFR CIGS BACK AN HOUR IN THE
METROPLEX TO 12Z AND WILL CONTINUE TO ONLY MENTION SCT MVFR FOR
WACO AS CONFIDENCE OF THE CLOUD DECK REACHING THAT FAR SOUTH IS
NOT THAT HIGH. OTHERWISE...NORTHWEST WINDS HAVE ENTERED THE METRO
SITES AND ARENT THAT FAR BEHIND FOR WACO. WINDS WILL SLOWLY VEER
TO THE NE BY THE END OF THE PERIOD.
85/NH
&&
.UPDATE...
THE DENSE FOG CONTINUED TO PUSH WEST AND WENT AHEAD AND ADDED THE
EASTERN ROW OF COUNTIES TO THE ADVISORY. UPDATED PRODUCTS HAVE
BEEN SENT.
85/NH
&&
.PREV DISCUSSION... /ISSUED 331 PM CST WED FEB 15 2012/
DRYLINE PUSHING THROUGH THE EASTERN PORTIONS OF THE AREA WITH
ONLY SMALL CHANCE OF PRECIP EAST OF THE DRYLINE OVER THE NEXT
COUPLE OF HOURS. DRYLINE WILL LOSE ITS EASTWARD PUNCH THIS
EVENING AND WILL BE OVERTAKEN TONIGHT BY A COLD FRONT CURRENTLY
LOCATED OVER NW OK/TX. AN AREA OF WRAPAROUND CLOUDS OVER THE TX/OK
PANHANDLES WILL MOVE SOUTHEASTWARD BUT WILL SCATTER OUT AS THEY
MOVE INTO NORTH TEXAS.
WATER VAPOR SHOWS OUR NEXT SYSTEM OVER CA. STILL SOME DISAGREEMENT
IN THE MODELS OVER THE EXACT TRACK AND STRENGTH OF THE SYSTEM BUT
IT DOES APPEAR THAT WE WILL START TO SEE SOME LIFT AHEAD OF THE
SYSTEM FRIDAY AFTERNOON AND NIGHT AS WARM AIR ADVECTION OVERRIDES
A FAIRLY COOL AIRMASS AT THE SURFACE. INSTABILITY WITH THIS SYSTEM
LOOKS TO BE MINIMAL THOUGH SOME THUNDER WILL BE POSSIBLE OVER THE
SOUTHERN ZONES.
UPPER TROF OPENS UP AND PUSHES ACROSS NORTH TEXAS SATURDAY
AFTERNOON EFFECTIVELY ENDING OUR RAIN CHANCES. WITH CLOUDS HANGING AROUND
THROUGH THE DAY THOUGH...IT DOES LOOK TO BE A COOL DAY ACROSS THE
AREA.
UPPER AIR PATTERN REMAINS QUITE PROGRESSIVE AND NEXT SYSTEM WILL
PUSH ACROSS THE SOUTHERN ROCKIES ON TUESDAY. WILL AGAIN SEE A
CHANCE OF RAIN WITH THIS SYSTEM BUT TIMING STILL AN UNCERTAINTY SO
WILL BROAD BUSH WILL LOW POPS FOR NOW. 99
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 41 62 42 59 42 / 0 0 10 20 40
WACO, TX 43 63 44 58 47 / 0 0 10 30 50
PARIS, TX 44 61 40 61 41 / 0 0 10 10 40
DENTON, TX 42 60 40 58 40 / 0 0 10 20 40
MCKINNEY, TX 42 63 41 58 41 / 0 0 10 20 40
DALLAS, TX 41 63 42 60 42 / 0 0 10 20 50
TERRELL, TX 42 63 42 59 40 / 0 0 10 20 50
CORSICANA, TX 44 65 43 61 47 / 0 0 10 20 50
TEMPLE, TX 45 66 45 60 47 / 0 0 10 30 50
MINERAL WELLS, TX 39 58 40 58 41 / 0 0 10 20 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR TXZ094-095-106-
107-122-123-135-148-162.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
412 AM MST THU FEB 16 2012
.SHORT TERM...SKIES HAVE ALREADY BECOME TO CLEAR EAST OF THE
MTNS EARLY THIS MORNING AS THE SHORTWAVE PASSES BY. THE CLEARING
HAS OPEN THE DOOR TO THE POSSIBILITY OF SOME FOG FORMATION ON THE
PLAINS IN THE NEXT HOUR OR SO. HRRR MODEL SHOWS POCKETS OF
SATURATED BNDRY LAYER AIR ALONG THE SOUTH PLATTE AND AROUND
D.I.A.. LATEST OBS FROM D.I.A. INDICATES 5 MILES IN FOG. COULD SEE
VSBYS AT D.I.A. BRIEFLY LOWERING TO 2-3 MILES BEFORE MIXING OUT
AROUND 15Z WITH ARRIVAL OF DRIER SWLY BREEZES. OTHERWISE THE FEW
REMAINING OROGRAPHIC SNOW SHOWERS UP ALONG THE CONTINENTAL DIVIDE
SHOULD BEGIN TO TAPER OFF IN THE NEXT 4 HRS OR SO AND END IN MOST
AREAS BY EARLY THIS AFTERNOON WITH LITTLE IF ANY ACCUMULATION
ANTICIPATED. SHOULD SEE CLEARING THROUGH THE DAY WITH A DRIER
WEST-NORTHWESTERLY FLOW ALOFT IN THE WAKE OF THE UPPER TROUGH.
HIGH TEMPS TODAY ABOUT 8-10F WARMER THAN YESTERDAY WITH WARMEST
READINGS NEAR THE FOOTHILLS. STILL READINGS ABOUT 3-5F BELOW
AVERAGE FOR THE DATE.
.LONG TERM...THE WEATHER PATTERN FOR THE NEXT WEEK WILL HAVE A
SERIES OF GENERALLY WEAK WAVES MOVING ACROSS COLORADO. THE
MOUNTAINS WILL HAVE THE BEST CHANCE OF BENEFITING FROM THESE
WAVES. THIS FIRST ONE WILL MOVE ACROSS COLORADO LATE FRIDAY
AFTERNOON AND NIGHT WITH A CHANCE OF LIGHT SNOW IN THE MOUNTAINS.
THIS LOOKS LIKE A VERY LIGHT SNOWFALL AS OROGRAPHIC FLOW IS QUITE
WEAK...UNDER 10KT WHILE THE MOISTURE QG ASCENT ARE OUT OF PHASE.
EXPECT AMOUNTS AROUND AN INCH OR LESS. AS FOR THE NORTHEAST
PLAINS...THERE WILL BE A WEAK FRONTAL BOUNDARY MOVING IN FRIDAY
AFTERNOON BUT NOT MUCH MOISTURE TO GENERATE ANY PRECIP WITH
GENERALLY A MID LEVEL CLOUD DECK LIKELY.
HIGH PRESSURE RIDGING ALOFT BUILDS IN ON SATURDAY WITH A DRIER
AIRMASS IN PLACE STATEWIDE WITH SLIGHTLY WARMER TEMPERATURES. THE
RIDGE ALOFT SHIFTS EAST INTO THE CENTRAL PLAINS ON SUNDAY IN
RESPONSE TO NEXT INCOMING PACIFIC STORM SYSTEM. THIS SYSTEM LOOKS
STRONGER AND A BIT DEEPER BUT MODEL SOLUTIONS ARE QUITE VARIED IN
THE DEVELOPMENT AND HANDLING OF THE ENERGY. THE GFS SHOWS THE
DEVELOPMENT OF A CLOSED LOW NEAR THE 4 CORNERS ON LATE MONDAY
WHILE THE EUROPEAN SOLUTION IS MORE PROGRESSIVE AND WEAKER AS IT
MOVES ACROSS COLORADO. CURRENT WEATHER GRIDS ALREADY HAVE A CHANCE
OF SNOW OVER MUCH OF THE AREA AND THIS LOOKS FINE FOR NOW UNTIL
DETAILS BECOME A BIT CLEARER.
&&
.AVIATION...CLEARING SKIES HAS ALLOWED FOR POCKETS OF FOG TO FORM
IN AND NEAR D.I.A. IN THE PAST HOUR. SHOULD CONTINUE TO SEE
POCKETS OF FOG FLOATING AROUND D.I.A. AND POINTS TO THE EAST-
NORTHEAST OF THE DENVER FOR THE NEXT 3-5 HOURS. COULD SEE THE
VISIBILITY BRIEF DROP TO 2 MILES OR SO AT D.I.A. BEFORE DRIER AIR
ARRIVES FROM THE SOUTHWEST. WINDS LIGHT AND VARIABLE SHOULD GO
SOUTHWESTERLY AT 4-7KTS AFTER 15Z THIS MORNING. OTHERWISE VFR
CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS AT DENVER AREA
AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....ENTREKIN
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1023 AM EST THU FEB 16 2012
.SYNOPSIS...
LOW PRESSURE WILL BRING SHOWERS ACROSS THE UPPER OHIO VALLEY THIS
AFTERNOON WITH LINGERING PATCHY DRIZZLE POSSIBLE TONIGHT BEHIND A
FRONTAL BOUNDARY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION,
BRINGING DRY WEATHER TO THE AREA THROUGH EARLY SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST RADAR/TEMP TRENDS AND TO ADD THE MENTION OF
DRIZZLE/FZDZ AFTER 03Z.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A WEAK SHORT WAVE
TROUGH LOCATED ALONG THE INDIANA/OHIO BORDER WITH A VORT MAX AT
ITS BASE. THIS FEATURE ALONG WITH A BROAD SURFACE TROUGH ARE
PROVIDING FORCING FOR RAIN AHEAD OF A WEAK COLD FRONT IN INDIANA.
THIS AFTERNOON...THE SURFACE TROUGH WILL MOVE ACROSS THE OHIO
VALLEY INTO WESTERN PENNSYLVANIA. THIS WILL ALLOW FOR A FAIRLY
WIDESPREAD AREA OF RAIN TO CONTINUE TO PUSH ACROSS THE AREA. MID-
LEVEL VORT ENERGY WILL PUSH EAST OF THE AREA, ENDING MORE
WIDESPREAD FORCING FOR ASCENT BY 21Z. AFTERWARD, HRRR SUPPORTS
MORE SCATTERED SHOWERS ARE EXPECTED THROUGH THE EVENING AHEAD OF
THE FRONT. WEAK WARM AIR ADVECTION WILL CONTINUE AHEAD OF THE
FRONT TODAY, WITH TEMPS A FEW DEGREES WARMER THAN LAMP GUIDANCE.
HIGHS WILL RANGE FROM THE LOWER 40S ACROSS THE EASTERN RIDGES AND
I-80 CORRIDOR TO NEAR 50 IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV.
TONIGHT...THE FRONTAL BOUNDARY AND DEEPER MOISTURE WILL SHIFT EAST
OF THE AREA AFTER 00Z, WISH LOW-LEVEL MOISTURE LINGERING IN ITS
WAKE. DESPITE THICKNESSES DECREASING, DRY AIR ALOFT IN THE
DENDRITIC GROWTH ZONE WILL PREVENT SNOW SHOWERS AND ALLOW FOR
PATCHES OF DRIZZLE AND FREEZING DRIZZLE OVERNIGHT. OVERNIGHT LOWS
ARE A MAV/MET BLEND, IN THE UPPER 20S TO LOWER 30S ACROSS MUCH OF
THE AREA.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
SURFACE HIGH PRESSURE WILL BRING DRY AND NEAR SEASONAL
TEMPERATURES INTO EARLY SATURDAY. SHORTWAVE AND WEAK FRONT WILL
SLIDE ACROSS EASTERN LAKES LATER SATURDAY INTO SATURDAY NIGHT WITH
MAINLY AN INCREASE IN CLOUDS AS DEEP MOISTURE WILL BE LACKING.
TEMPERATURES SATURDAY WILL RISE ABOVE NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SPLIT FLOW IN UPPER LEVEL JET STREAM WITH SOUTHERN STREAM SYSTEM
DEVELOPING ACROSS THE GULF COAST STATES WILL SPREAD PRECIPITATION
INTO THE SOUTHEAST RIDGES SUNDAY. ECMWF HAS TRENDED TOWARD GFS
SOLUTION WITH A MORE NORTHERLY TRACK SO RAISED POPS ACROSS THE
SOUTHEAST. LITTLE CHANGE IN REMAINDER OF EXTENDED FORECAST WITH
DRY HIGH PRESSURE MONDAY INTO TUESDAY BEFORE NEXT LOW PRESSURE
SYSTEM BRINGS A CHANCE FOR SHOWERS LATER TUESDAY INTO WEDNESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM APPROACHING THE SOUTHERN GREAT LAKES WILL
BRING RESTRICTIONS TO ALL SITES. RESTRICTIONS WILL GENERALLY REMAIN
IN THE WAY OF MVFR/IFR CIGS. HOWEVER...IFR VSBYS IN FOG ARE
OCCURRING UPSTREAM OVER INDIANA AND OHIO. FOR NOW...MAINTAINED
MAINLY MVFR VISBYS BASED OFF OF THE MOST RECENT LAMP...NAM...AND
SREF GUIDANCE.
SE WINDS WILL VEER TO THE W-SW WITH THE FRONTAL PASSAGE LATE TODAY.
SPEEDS WILL REMAIN AROUND 5-10KTS.
OUTLOOK...FRIDAY THROUGH MONDAY...
CEILING RESTRICTIONS WILL CONTINUE THROUGH EARLY FRIDAY BEFORE
IMPROVEMENT TO VFR IN HIGH PRESSURE FOR THE BEGINNING OF THE
WEEKEND. ANOTHER SYSTEM PASSING TO THE SOUTHEAST MAY BRING
RESTRICTIONS SOUTHEAST OF KPIT WITH SNOW LATE SATURDAY AND SUNDAY.
HIGH PRESSURE WILL RETURN VFR CONDITIONS FOR EARLY NEXT WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1035 AM MST THU FEB 16 2012
.UPDATE...CURRENT FORECASTS STILL ON TRACK. WILL LEAVE A SLIGHT
CHANCE OF SNOW FOR THE HIGHER MOUNTAINS. STILL SOME MOISTURE
TRAPPED IN THE HIGHER AREAS. SO DESPITE THE WEAK OROGRAPHICS AND
LAPSE RATES...MAY SEE SOME FLURRIES THROUGH THE EVENING.
&&
.AVIATION...SOUTHERLY WINDS HAVE INCREASED A BIT AT KDEN WHICH
HELPED FLUSH OUT ANY REMAINING HINTS AT FOG. CURRENT TAF TRENDS
LOOKING REASONABLE...FEW CHANGES NEEDED FOR THIS PACKAGE. SHOULD
BEGIN TO SEE SOME INCREASE IN MID AND HIGH LEVEL MOISTURE SOMETIME
AFTER MIDNIGHT. CURRENT MODEL RUNS SUGGEST FRONT MOVING ACROSS
AREA AIRPORTS AROUND 20Z. POTENTIAL FOR CEILINGS OF AROUND 6000
FEET AGL DEVELOPING BY LATE AFTERNOON...ADDED A TEMPO GROUP AT
KDEN AFTER 20Z.
&&
.PREV DISCUSSION... /ISSUED 412 AM MST THU FEB 16 2012/
SHORT TERM...SKIES HAVE ALREADY BECOME TO CLEAR EAST OF THE
MTNS EARLY THIS MORNING AS THE SHORTWAVE PASSES BY. THE CLEARING
HAS OPEN THE DOOR TO THE POSSIBILITY OF SOME FOG FORMATION ON THE
PLAINS IN THE NEXT HOUR OR SO. HRRR MODEL SHOWS POCKETS OF
SATURATED BNDRY LAYER AIR ALONG THE SOUTH PLATTE AND AROUND
D.I.A.. LATEST OBS FROM D.I.A. INDICATES 5 MILES IN FOG. COULD SEE
VSBYS AT D.I.A. BRIEFLY LOWERING TO 2-3 MILES BEFORE MIXING OUT
AROUND 15Z WITH ARRIVAL OF DRIER SWLY BREEZES. OTHERWISE THE FEW
REMAINING OROGRAPHIC SNOW SHOWERS UP ALONG THE CONTINENTAL DIVIDE
SHOULD BEGIN TO TAPER OFF IN THE NEXT 4 HRS OR SO AND END IN MOST
AREAS BY EARLY THIS AFTERNOON WITH LITTLE IF ANY ACCUMULATION
ANTICIPATED. SHOULD SEE CLEARING THROUGH THE DAY WITH A DRIER
WEST-NORTHWESTERLY FLOW ALOFT IN THE WAKE OF THE UPPER TROUGH.
HIGH TEMPS TODAY ABOUT 8-10F WARMER THAN YESTERDAY WITH WARMEST
READINGS NEAR THE FOOTHILLS. STILL READINGS ABOUT 3-5F BELOW
AVERAGE FOR THE DATE.
LONG TERM...THE WEATHER PATTERN FOR THE NEXT WEEK WILL HAVE A
SERIES OF GENERALLY WEAK WAVES MOVING ACROSS COLORADO. THE
MOUNTAINS WILL HAVE THE BEST CHANCE OF BENEFITING FROM THESE
WAVES. THIS FIRST ONE WILL MOVE ACROSS COLORADO LATE FRIDAY
AFTERNOON AND NIGHT WITH A CHANCE OF LIGHT SNOW IN THE MOUNTAINS.
THIS LOOKS LIKE A VERY LIGHT SNOWFALL AS OROGRAPHIC FLOW IS QUITE
WEAK...UNDER 10KT WHILE THE MOISTURE QG ASCENT ARE OUT OF PHASE.
EXPECT AMOUNTS AROUND AN INCH OR LESS. AS FOR THE NORTHEAST
PLAINS...THERE WILL BE A WEAK FRONTAL BOUNDARY MOVING IN FRIDAY
AFTERNOON BUT NOT MUCH MOISTURE TO GENERATE ANY PRECIP WITH
GENERALLY A MID LEVEL CLOUD DECK LIKELY.
HIGH PRESSURE RIDGING ALOFT BUILDS IN ON SATURDAY WITH A DRIER
AIRMASS IN PLACE STATEWIDE WITH SLIGHTLY WARMER TEMPERATURES. THE
RIDGE ALOFT SHIFTS EAST INTO THE CENTRAL PLAINS ON SUNDAY IN
RESPONSE TO NEXT INCOMING PACIFIC STORM SYSTEM. THIS SYSTEM LOOKS
STRONGER AND A BIT DEEPER BUT MODEL SOLUTIONS ARE QUITE VARIED IN
THE DEVELOPMENT AND HANDLING OF THE ENERGY. THE GFS SHOWS THE
DEVELOPMENT OF A CLOSED LOW NEAR THE 4 CORNERS ON LATE MONDAY
WHILE THE EUROPEAN SOLUTION IS MORE PROGRESSIVE AND WEAKER AS IT
MOVES ACROSS COLORADO. CURRENT WEATHER GRIDS ALREADY HAVE A CHANCE
OF SNOW OVER MUCH OF THE AREA AND THIS LOOKS FINE FOR NOW UNTIL
DETAILS BECOME A BIT CLEARER.
AVIATION...CLEARING SKIES HAS ALLOWED FOR POCKETS OF FOG TO FORM
IN AND NEAR D.I.A. IN THE PAST HOUR. SHOULD CONTINUE TO SEE
POCKETS OF FOG FLOATING AROUND D.I.A. AND POINTS TO THE EAST-
NORTHEAST OF THE DENVER FOR THE NEXT 3-5 HOURS. COULD SEE THE
VISIBILITY BRIEF DROP TO 2 MILES OR SO AT D.I.A. BEFORE DRIER AIR
ARRIVES FROM THE SOUTHWEST. WINDS LIGHT AND VARIABLE SHOULD GO
SOUTHWESTERLY AT 4-7KTS AFTER 15Z THIS MORNING. OTHERWISE VFR
CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS AT DENVER AREA
AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DES MOINES IA
326 PM CST THU FEB 16 2012
.SHORT TERM /TONIGHT/...
LATEST WV IMAGERY WITH H500 RUC ANALYSIS SHOWED CONFLUENT UPPER
LEVEL FLOW ACROSS THE MISSOURI RIVER VALLEY...WITH A WEAK SHORTWAVE
APPROACHING THE MT/ND BORDER. SURFACE ANALYSIS DEPICTED 1025MB HIGH
CENTERED OVER KS/MO BORDER...WITH A NORTH/SOUTH ORIENTED TROUGH
LOCATED OVER THE CENTRAL DAKOTAS IN ASSOCIATION WITH THE
AFOREMENTIONED SHORTWAVE.
AS THE WEAK UPPER LEVEL WAVE MOVES SOUTHEAST ACROSS THE DAKOTAS
OVERNIGHT...AND THE SURFACE HIGH MEANDERS EASTWARD...THE LOW LEVEL
WINDS WILL GRADUALLY BACK FROM THE WEST TOWARD THE SOUTHWEST
OVERNIGHT. THEY SHOULD REMAIN STRONG ENOUGH TO MITIGATE ANY
WIDESPREAD DENSE FOG. HOWEVER...TIME HEIGHT CROSS SECTIONS SHOW SOME
LOW LEVEL MOISTURE DEVELOPING BY MORNING...SO FEEL THAT PATCHY FOG
IS POSSIBLE...ESPECIALLY ACROSS SNOW COVERED AREAS. FOR OVERNIGHT
LOW TEMPS WENT WITH THE BIAS-CORRECTED GUIDANCE.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
FORECAST CHALLENGE THROUGH THE PERIOD REMAINS THE UPPER LEVEL SYSTEM
IMPACTING THE MIDWEST EARLY NEXT WEEK. BEFORE THEN...SHORT WAVE
ENERGY DROPPING SOUTHEAST THROUGH ERN MONTANA/WRN NORTH DAKOTA WILL
PUSH THROUGH FRIDAY MORNING. GOOD KINEMATICS AND A PUSH OF
TEMPERATURE ADVECTION WILL ARRIVE WITH THE SYSTEM. THE SYSTEM WILL
BE LACKING MOISTURE HOWEVER. THAT SAID...IT APPEARS TO BE A SMALL
WINDOW WITH FLURRIES OR WORST CASE SCENARIO A LIGHT SNOW SHOWER TO
MOVE THROUGH INTO MID MORNING. A SFC BOUNDARY WILL MOVE THROUGH
DURING THE DAY ON FRIDAY AS WELL. IT WILL NOT REACH THE SOUTHEAST
UNTIL THE AFTERNOON...THEREFORE A GOOD WARMUP AHEAD OF BOUNDARY IS
POSSIBLE. THE COLD ADVECTION WILL BE FOCUSED NEAR 925 MB WITH THE
SFC IMPACT LAGGING. WITH THIS...MIXING WILL OCCUR AND LIMIT THE SFC
IMPACT ON TEMPERATURES DURING THE DAY. ANOTHER BOUNDARY WILL DROP
SOUTH FRIDAY NIGHT AND WILL LEAD TO A COOLER YET DRY WEEKEND.
STILL A COMPLEX SITUATION EARLY NEXT WEEK WITH AN ACTIVE FLOW AND
NUMEROUS PIECES OF ENERGY MOVING THROUGH THE LONG WAVE TROUGH. THE
FOCUS IS ON THREE OF THE EMBEDDED IMPULSES WITH ONE NORTH INTO
CANADA...ONE IMPACTING THE MIDWEST AND ANOTHER DROPPING WELL TO THE
SOUTH. EACH COULD CERTAINLY IMPACT THE OTHERS REGARDING TIMING AND
PLACEMENT BUT AT THIS TIME...SOME CONSENSUS DEVELOPING REGARDING
EACH. FOCUS FOR PRECIPITATION WILL BE LATE MONDAY THROUGH EARLY
TUESDAY. TRENDS ARE SUGGESTING THE PRECIPITATION COULD BE MOSTLY
SNOW OVER THE NORTH WITH A MIX OR EVEN ALL RAIN TO THE SOUTH. THE
FLOW WILL REMAIN ACTIVE FOR THE REMAINDER OF THE EXTENDED WITH
ADDITIONAL POTENTIAL FOR PRECIPITATION AND TEMPERATURES GENERALLY
NEAR TO ABOVE SEASONAL VALUES.
&&
.AVIATION...16/18Z
VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS. ONLY CAVEAT WILL
BE POTENTIAL FOR SOME PATCHY FOG DURING THE LATE NIGHT/EARLY MORNING
HOURS. HOWEVER...WESTERLY WINDS SHOULD LIMIT THE COVERAGE...SO
CURRENTLY HAVE NO RESTRICTIONS. WIND WILL SHIFT FROM THE WEST TO
SOUTHWEST BY TOMORROW MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEITLICH
LONG TERM...DONAVON
AVIATION...BEITLICH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
337 PM EST THU FEB 16 2012
.SYNOPSIS...
SHOWERS WILL DIMINISH ACROSS THE UPPER OHIO VALLEY THIS EVENING WITH
LINGERING PATCHY DRIZZLE POSSIBLE OVERNIGHT BEHIND A FRONTAL
BOUNDARY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION, BRINGING
DRY WEATHER TO THE AREA THROUGH EARLY SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A WEAK SHORT WAVE
TROUGH LOCATED ACROSS WESTERN PENNSYLVANIA WITH A VORT MAX
SHIFTING ACROSS THE EASTERN RIDGES. A WEAK COLD FRONT IS LOCATED
ACROSS CENTRAL OHIO, WITH STRATUS MOVING ACROSS THE AREA.
TONIGHT...THE FRONTAL BOUNDARY AND DEEPER MOISTURE WILL SHIFT EAST
OF THE AREA WITH LOW-LEVEL MOISTURE LINGERING IN ITS WAKE. DESPITE
THICKNESSES DECREASING, DRY AIR ALOFT IN THE DENDRITIC GROWTH ZONE
WILL PREVENT SNOW SHOWERS AND ALLOW FOR PATCHES OF DRIZZLE AND
FREEZING DRIZZLE OVERNIGHT. OVERNIGHT LOWS ARE A MAV/MET BLEND, IN
THE UPPER 20S TO LOWER 30S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THERE IS STRONG OPERATIONAL MODEL AGREEMENT THAT THE REGION WILL BE
IN A ZONAL FLOW WITH HIGH PRESSURE AND A DEEP LAYER OF DRY AIR ABOVE
850MB MOVING ACROSS THE OHIO VALLEY AND INTO THE AREA ON FRIDAY.
THE FORECAST WILL REMAIN MOSTLY DRY AS THE HIGH SHIFTS EAST OF
REGION ON SATURDAY. THE EXCEPTION IS THE CHC OF SNOW NORTH OF
PITTSBURGH ON SATURDAY AFTERNOON AS A WEAK LOW MOVES ACROSS THE
SOUTHERN GREAT LAKES. TEMPERATURES THROUGH THIS PERIOD WILL BE
AROUND 5 DEGREES ABOVE NORMAL.
SATURDAY NIGHT INTO SUNDAY...A WEEKEND SNOW EVENT FOR THE
SOUTHEAST RIDGES APPEARS TO BE COMING INTO BETTER FOCUS NOW.
NORTHERN AND SOUTHERN STREAM TROUGHS WILL PHASE AS THEY MOVE ACROSS
THE TENNESSEE VALLEY AND MOVE INTO THE CAROLINAS. 12Z NAM/GFS RUNS
HAVE TRENDED FURTHER NORTH WITH THE SURFACE LOW AND THE NORTHERN
EXTENT OF ITS PRECIPITATION SHIELD. FOR SNOW AMOUNTS, THIS EVENT MAY
NEED FUTURE WINTER STORM WATCHES AND WARNINGS, AS DETERMINISTIC
MODELS SHOW THE POTENTIAL FOR 6 TO 12 INCHES OF WET SNOW ACROSS
TUCKER AND GARRETT COUNTIES WITH THE LOWER END OF THE ENVELOPE
POSSIBLE FOR PRESTON COUNTY. WITH THIS IN MIND, HAVE ADDED MENTION
OF THIS TO THE HWO.
FOR THE REMAINDER OF THE FORECAST AREA, THE NORTHERN EXTENT OF
DEEPER MOISTURE WITH SNOW LOOKS TO REMAIN SOUTHEAST OF PITTSBURGH,
WITH ONLY LIGHT ACCUMULATION IF ANY POSSIBLE FOR THESE LOCATIONS.
OTHERWISE, A DRY FORECAST IS IN PLACE AS HIGH PRESSURE APPROACHES
FROM THE UPPER MIDWEST. TEMPERATURES WILL BE A FEW DEGREES BELOW
NORMAL THROUGH THIS PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
STORM SYSTEM MOVING UP THE EAST COAST WILL WRAP UP SUNDAY NIGHT
ALONG THE RIDGES. HIGH PRESSURE WILL THEN BRING DRY CONDITIONS FOR
MONDAY INTO EARLY TUESDAY. MODEL DETAILS BECOME FUZZY BY TUESDAY
NIGHT...BUT MULTIPLE WAVES WILL MOVE ACROSS THE EASTERN UNITED
STATES FOR THE MIDDLE PART OF THE WORK WEEK. THIS UNSETTLED PATTERN
WILL KEEP CHANCE POPS FOR THE REST OF THE FORECAST. DAYTIME
TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL...WITH OVERNIGHT
LOWS COLD ENOUGH TO ALLOW FOR THE POSSIBILITY OF SNOW EACH EVENING.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
RAIN SHOWERS WILL CLEAR ALL TERMINALS BY MID AFTERNOON. PRIMARY
FLIGHT IMPACT THIS AFTERNOON WILL BE WIDESPREAD IFR CIGS...WITH
ISOLATED LIFR CIGS. VISIBILITIES HAVE ALSO BEEN LOW BEHIND THE COLD
FRONT CURRENTLY ACROSS WESTERN/CENTRAL OHIO...AND WINDS WILL SHIFT
TO THE WEST AS THE FRONT MOVES THROUGH THIS AFTERNOON/EVENING.
BEHIND THE FRONT...CLOUDS WILL BE SLOW TO RISE AND SCATTER OUT. HAVE
KEPT RESTRICTIONS IN A BIT LONGER OVERNIGHT THAN MODEL GUIDANCE
SUGGESTS. ON FRIDAY AFTERNOON...WINDS WILL GUST UP TO 20 KTS OUT OF
THE WEST...ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN VFR.
OUTLOOK...FRIDAY THROUGH TUESDAY...
EXPECT VFR CONDITIONS TO CONTINUE FRIDAY NIGHT INTO EARLY SATURDAY
WITH HIGH PRESSURE OVERHEAD. LOW PRESSURE MOVING ACROSS THE EASTERN
GREAT LAKES COULD CLIP NORTHERN TERMINALS WITH RESTRICTIONS SATURDAY
AFTERNOON INTO SATURDAY NIGHT. A DEVELOPING LOW PRESSURE SYSTEM OFF
THE ATLANTIC COAST COULD THEN CLIP SOUTHEASTERN TERMINALS SUCH AS
LBE AND MGW SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL THEN
BRING VFR CONDITIONS FOR SUNDAY NIGHT INTO TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
132 PM EST THU FEB 16 2012
.SYNOPSIS...
SHOWERS WILL DIMINISH ACROSS THE UPPER OHIO VALLEY THIS AFTERNOON
WITH LINGERING PATCHY DRIZZLE POSSIBLE TONIGHT BEHIND A FRONTAL
BOUNDARY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION, BRINGING
DRY WEATHER TO THE AREA THROUGH EARLY SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
BRING WIDESPREAD PRECIPITATION TO AN END EARLIER THIS AFTERNOON
WITH A CHANCE OF SHOWERS BEHIND IT INTO THE EVENING.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A WEAK SHORT WAVE
TROUGH LOCATED ALONG THE OHIO/PENNSYLVANIA BORDER WITH A VORT MAX
AT ITS BASE IN SOUTHERN OHIO. THIS FEATURE ALONG WITH A BROAD SURFACE
TROUGH ARE PROVIDING FORCING FOR RAIN AHEAD OF A WEAK COLD FRONT
IN INDIANA.
THIS AFTERNOON...THE SURFACE TROUGH WILL MOVE ACROSS WESTERN
PENNSYLVANIA. WIDESPREAD RAIN WILL QUICKLY COME TO AN WITH JUST
THE CHANCE FOR SHOWERS AHEAD OF A FRONTAL BOUNDARY. AFTERWARD,
HRRR SUPPORTS MORE SCATTERED SHOWERS THROUGH THE EVENING AHEAD OF
THE FRONT. WEAK WARM AIR ADVECTION WILL CONTINUE AHEAD OF THE
FRONT TODAY, WITH TEMPS A FEW DEGREES WARMER THAN LAMP GUIDANCE.
HIGHS WILL RANGE FROM THE LOWER 40S ACROSS THE EASTERN RIDGES AND
I-80 CORRIDOR TO NEAR 50 IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV.
TONIGHT...THE FRONTAL BOUNDARY AND DEEPER MOISTURE WILL SHIFT EAST
OF THE AREA WITH LOW-LEVEL MOISTURE LINGERING IN ITS WAKE. DESPITE
THICKNESSES DECREASING, DRY AIR ALOFT IN THE DENDRITIC GROWTH ZONE
WILL PREVENT SNOW SHOWERS AND ALLOW FOR PATCHES OF DRIZZLE AND
FREEZING DRIZZLE OVERNIGHT. OVERNIGHT LOWS ARE A MAV/MET BLEND, IN
THE UPPER 20S TO LOWER 30S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
SURFACE HIGH PRESSURE WILL BRING DRY AND NEAR SEASONAL
TEMPERATURES INTO EARLY SATURDAY. SHORTWAVE AND WEAK FRONT WILL
SLIDE ACROSS EASTERN LAKES LATER SATURDAY INTO SATURDAY NIGHT WITH
MAINLY AN INCREASE IN CLOUDS AS DEEP MOISTURE WILL BE LACKING.
TEMPERATURES SATURDAY WILL RISE ABOVE NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SPLIT FLOW IN UPPER LEVEL JET STREAM WITH SOUTHERN STREAM SYSTEM
DEVELOPING ACROSS THE GULF COAST STATES WILL SPREAD PRECIPITATION
INTO THE SOUTHEAST RIDGES SUNDAY. ECMWF HAS TRENDED TOWARD GFS
SOLUTION WITH A MORE NORTHERLY TRACK SO RAISED POPS ACROSS THE
SOUTHEAST. LITTLE CHANGE IN REMAINDER OF EXTENDED FORECAST WITH
DRY HIGH PRESSURE MONDAY INTO TUESDAY BEFORE NEXT LOW PRESSURE
SYSTEM BRINGS A CHANCE FOR SHOWERS LATER TUESDAY INTO WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
RAIN SHOWERS WILL CLEAR ALL TERMINALS BY MID AFTERNOON. PRIMARY
FLIGHT IMPACT THIS AFTERNOON WILL BE WIDESPREAD IFR CIGS...WITH
ISOLATED LIFR CIGS. VISIBILITIES HAVE ALSO BEEN LOW BEHIND THE COLD
FRONT CURRENTLY ACROSS WESTERN/CENTRAL OHIO...AND WINDS WILL SHIFT
TO THE WEST AS THE FRONT MOVES THROUGH THIS AFTERNOON/EVENING.
BEHIND THE FRONT...CLOUDS WILL BE SLOW TO RISE AND SCATTER OUT. HAVE
KEPT RESTRICTIONS IN A BIT LONGER OVERNIGHT THAN MODEL GUIDANCE
SUGGESTS. ON FRIDAY AFTERNOON...WINDS WILL GUST UP TO 20 KTS OUT OF
THE WEST...ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN VFR.
OUTLOOK...FRIDAY THROUGH TUESDAY...
EXPECT VFR CONDITIONS TO CONTINUE FRIDAY NIGHT INTO EARLY SATURDAY
WITH HIGH PRESSURE OVERHEAD. LOW PRESSURE MOVING ACROSS THE EASTERN
GREAT LAKES COULD CLIP NORTHERN TERMINALS WITH RESTRICTIONS SATURDAY
AFTERNOON INTO SATURDAY NIGHT. A DEVELOPING LOW PRESSURE SYSTEM OFF
THE ATLANTIC COAST COULD THEN CLIP SOUTHEASTERN TERMINALS SUCH AS
LBE AND MGW SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL THEN
BRING VFR CONDITIONS FOR SUNDAY NIGHT INTO TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BILLINGS MT
948 AM MST THU FEB 16 2012
.SHORT TERM...VALID FOR TDY AND FRI...
ANOTHER WEAK SHORT WAVE TROUGH IS DROPPING INTO NORTHEASTERN PARTS
OF MT AS OF 16 UTC. THE 12 UTC RAOB DATA AND NOTABLE DRYING IN THE
MID- AND UPPER-LEVELS SHOWN ON MOISTURE CHANNEL IMAGERY SUPPORTS A
90 TO 100 KT 300-HPA JET STREAK ON THE BACK SIDE OF THE SHORT WAVE
OVER OUR AREA TODAY. SOME MODERATE Q-VECTOR CONVERGENCE RESULTS IN
MODEL SIMULATIONS...BUT WE WILL RETAIN THE GOING DRY FORECAST OVER
THE PLAINS GIVEN DRY FORECAST SOUNDING PROFILES. TEMPERATURES WILL
BE THE MAIN CHALLENGE TODAY...ESPECIALLY AS THE MID-LEVELS WARM IN
SOUTH CENTRAL MT WITH DOWNSLOPE FLOW PUSHING 850-HPA READINGS INTO
THE +1 TO +3 C RANGE. MANUAL MIX-DOWN FROM 800 HPA BASED ON 12 UTC
GFS AND RUC THERMAL PROFILES YIELDS HIGHS NEAR WHAT WE ARE ALREADY
ADVERTISING. ADMITTEDLY...WE COULD BE A BIT TOO WARM IN AREAS LIKE
BAKER AND MILES CITY WHERE MID-LEVELS COULD BE COOLER...BUT WE MAY
MAKE UP FOR THAT WITH THE DOWNSLOPE FLOW. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
PROGRESSIVE PATTERN IN THE EARLY PART OF THE EXTENDED AS A SHORT
LIVED RIDGE MOVES THROUGH MONTANA ON SATURDAY...BRINGING A WARMUP
INTO THE MID AND UPPER 40S FOR MOST OF THE AREA. WESTERN ZONES
WILL SEE SOME MOIST DIFFLUENT FLOW BY THE AFTERNOON AND EVENING ON
SATURDAY AND THIS SHOULD ALLOW FOR SHOWER ACTIVITY TO READILY
FORM.
BY SUNDAY MORNING A TROUGH IS WORKING ITS WAY INTO THE WESTERN
HALF OF THE STATE WITH THE MODELS A BIT MORE CONVINCED THAT A WEAK
UPPER LEVEL LOW WILL DEVELOP OVER NORTHERN MONTANA AND SOUTHEAST
ALBERTA DURING THE DAY. NORMALLY THIS IS A DRY SOLUTION BUT THERE
IS A SECOND PIECE OF ENERGY DIGGING INTO UTAH WHICH HAS A
SUBTROPICAL TAP SO THERE IS MOISTURE IN THE TROUGH AXIS OVER
SOUTHERN MONTANA AND NORTH CENTRAL WYOMING. THIS MOISTURE MAY BE
DEEP ENOUGH TO COMPENSATE FOR A LACK OF DYNAMICS TO ALLOW SHOWER
ACTIVITY TO HAVE PRETTY DECENT COVERAGE.
TROUGH AXIS MOVES LITTLE FOR MONDAY SO WITH MOISTURE ALREADY IN
THE REGION EXPECT ADDITIONAL SHOWER ACTIVITY WITH ONE PARTICULAR
AREA TO WATCH FOR BETTER PRECIPITATION. A WAVE SPINNING UP IN THE
LEE OF THE WYOMING/COLORADO ROCKIES HELPS DEEPEN AN INVERTED
SURFACE TROUGH OVER EASTERN WYOMING AND SOUTHEAST MONTANA. THIS
COULD BECOME THE FOCUS FOR A BAND OF STEADY PRECIPITATION WITH
ENOUGH DYNAMIC COOLING TO BECOME AN AREA OF SNOWFALL. GFS IS
WEAKER WITH THIS FEATURE THAN THE ECMWF PARTICULARLY BECAUSE THE
GFS HAS THE TROUGH TAKING ON A MORE POSITIVELY TILT WHICH WEAKENS
THE DYNAMICS. GIVEN A PRETTY QUIET EXTENDED FORECAST THIS FEATURE
MAY BE THE MOST IMPORTANT WEATHER EVENT SO WILL HAVE TO WATCH
SUNDAY NIGHT AND MONDAY CLOSELY.
TUESDAY AND BEYOND...MOIST NORTHWEST FLOW ALOFT WITH SURFACE
PATTERN SUPPORTING MIXING. THIS SHOULD KEEP OVERNIGHT LOW
TEMPERATURES FROM FALLING MUCH BELOW 20 AND THIS ALLOWS DAYTIME
TEMPS TO CONSISTENTLY REACH THE MID 40S. SHOWERS WILL LIKELY CROSS
THE REGION AS DISTURBANCES PASS THROUGH WITH THE MOUNTAINS SEEING
STEADY ACCUMULATING SNOW. BORSUM
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL TODAY...WITH ONLY INCREASING HIGH
CLOUDS THIS AFTERNOON AND EVENING. SW WINDS OF 20 TO 25
KTS WITH GUSTS IN THE 30S WILL CONTINUE AT KLVM...WHILE KBIL AND
AREAS ACROSS EASTERN MONTANA WILL SEE 15 TO 20 KNOT WINDS
BECOMING WNW THIS AFTERNOON. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 047 025/041 021/047 027/039 021/038 023/044 024/043
1/N 32/W 01/B 43/J 22/J 13/J 33/W
LVM 044 023/040 018/046 022/039 017/037 018/040 021/039
1/N 42/J 02/W 53/J 22/J 23/J 33/J
HDN 048 022/042 017/048 025/041 021/041 021/045 024/045
1/N 32/W 01/B 33/J 22/J 12/J 33/J
MLS 045 018/039 017/046 025/041 022/039 022/044 024/043
1/B 22/J 01/B 22/J 22/J 12/J 33/J
4BQ 044 021/038 017/045 025/040 021/039 021/043 023/042
1/N 12/J 11/U 13/J 32/J 12/J 33/J
BHK 042 017/036 014/045 022/041 019/038 019/041 024/039
1/B 12/J 11/U 12/J 22/J 12/J 33/J
SHR 044 020/038 014/046 022/040 018/038 018/041 022/040
1/B 32/J 11/U 34/J 32/J 12/J 34/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS