Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/16/11
AREA FORECAST DISCUSSION
NWS DENVER CO
1045 AM MST WED DEC 14 2011
.UPDATE...
&&
.SHORT TERM...NO CHANGES OF NOTES TO THE ZONES...MAY TWEAK SOME
WINDS FOR TODAY IN THE GRIDS. WEAK SURGE CAME ACROSS PLAINS THIS
MORNING BEHIND SYSTEM MOVING WELL TO OUR EAST BUT WIND DIRECTIONS
QUITE TRICKY NEAR THE FRONT RANGE WITH THE NW FLOW MAINLY FARTHER
OUT ON THE PLAINS AND IN AND NEAR THE FOOTHILLS RIGHT NOW. BUT
ENOUGH SUN AND MIXING TO GEET MOST TEMPERATURES INTO THE 40S THIS
AFTERNOON. A WEAK WAVE MOVING ACROSS WYOMING RIGHT NOW BUT THIS IS
WEAKENING WITH TIME AND LOOKS LIKE THE MAIN THING WITH THIS COULD
BE SOME INCREASE IN SNOW SHOWERS IN THE MOUNTAINS TONIGHT SO WILL
ASSESS THIS. PERSISTENCE THOUGH WOULD SUGGEST NOT A LOT WITH THIS
WAVE UNFORTUNATELY AND PLAINS LOOK DRY.
.AVIATION...TRICKY PART IS WINDS. AT DIA QUITE UNCERTAIN ABOUT
THEM EVER GOING NW AND INSTEAD BASED ON HRRR AND WRF SHORT RANGE
MODEL RUNS BROUGHT A WEAKISH NORTHERLY TO NE SHIFT IN THIS
AFTERNOON. THEN COMES AROUND TO SE THIS EVENING BEFORE DRAINAGE
SETS IN. APPEARS TO BE GOOD CHANCE OF A DENVER CYCLONE THURSDAY
AND PLAYED WINDS THAT WAY. BJC COULD HOWEVER SEE SOME W TO NW FLOW
INCREASE ALTHOUGH FOR NOW STAYING NEAR THE FOOTHILLS SO TRICKY
THERE AS WELL.
&&
.PREV DISCUSSION... /ISSUED 318 AM MST WED DEC 14 2011/
SHORT TERM...UPPER TROUGH AXIS CURRENTLY OVER WESTERN COLORADO AS
DEPICTED IN SATELLITE AND RADAR. SNOW IS INCREASING OVER THE HIGH
COUNTRY AS UPPER FLOW TRANSITIONS FROM SOUTHWEST TO NORTHWEST AND
LIFT INCREASES. NOT TOO MUCH MOISTURE LEFT WITH THIS SYSTEM THEN A
SHORTWAVE CURRENTLY OVER IDAHO WILL MOVE SOUTHEAST TO BRING A
LITTLE MORE SNOW THROUGH THE DAY AND TONIGHT. ALL TOGETHER
THOUGH...ONLY A FEW INCHES AT MOST THROUGH THE DAY. TEMPERATURES
TODAY WILL BE ABOUT 10 DEGREES LESS THAN YESTERDAY AS COLDER AIR
SPREADS OVER COLORADO BEHIND THE UPPER TROUGH. WESTERLY SURFACE
WINDS WILL ALSO BE INCREASING BEHIND THE TROUGH THROUGH THE DAY AS
THE LOW PRESSURE MOVES EAST. WILL SEE GUSTY WINDS IN THE FOOTHILLS
THIS AFTERNOON WITH SPEEDS OF 20 TO 35 MPH WITH GUSTS TO 45 MPH
POSSIBLE.
THE FOG OVER THE PLAINS CONTINUES TO PUSH SLIGHTLY EAST AS DRIER AIR
MOVES IN FROM THE WEST. KEEPING IN THE SLIGHT CHANCE OF LIGHT SNOW
OVER THE FAR EASTERN PLAINS AS THE AREA OF LIFT PASSES OVERHEAD THIS
MORNING. AS THE SYSTEM PUSHES EAST AND CLOUDS CLEAR...SOME SUN AND
THE MIXING FROM THE APPROACHING COLDER AIR FROM THE NORTH WILL ALLOW
ANY INVERSIONS OVER THE PLAINS TO BREAK AND ALLOW TEMPERATURES TO
WARM OVER YESTERDAYS READINGS. THE GUSTY WEST WINDS NEAR THE
FOOTHILLS WILL LET TEMPERATURES WARM A LITTLE MORE THERE...ALREADY
THIS MORNING THE NCAR MESA LAB HAS WARMED INTO THE UPPER 30S WITH
WEST WINDS WHILE JUST A SHORT DISTANCE AWAY TO ERIE ITS IN THE MID
TEENS. WEST TO NORTHWEST SURFACE WINDS ARE EXPECTED TO SPREAD OVER
THE PLAINS TODAY WITH CLEARING SKIES. WILL LIKELY SEE COLDER MINIMUM
TEMPERATURES TONIGHT WITH THE CLEAR SKIES AND COLDER AIRMASS FROM
THE NORTH.
LONG TERM...UPPER LEVEL RIDGE WILL BUILD OVER COLORADO ON THURSDAY
AS NEXT UPPER LEVEL LOW DRIVES SOUTHWARD ALONG THE WEST COAST. THIS
WILL RESULT IN MOSTLY SUNNY SKIES. HOWEVER...LACK OF DOWNSLOPE FLOW
ALONG WITH REMAINING SNOW COVER SHOULD KEEP HIGH TEMPS A COUPLE
DEGREES BELOW NORMAL.
ON FRIDAY...A SHORT WAVE MOVING ACROSS THE NORTHERN PLAINS STATES
WILL PUSH ANOTHER WEAK COLD FRONT ACROSS NORTHEAST COLORADO. THIS
SHOULD DROP TEMPS A COUPLE DEGREES FROM THURSDAYS HIGHS. NO
PRECIPITATION IS EXPECTED EVEN IN THE MOUNTAINS AS A GENERALLY DRY
AND SUBSIDENT AIRMASS WILL PREVAIL IN BETWEEN THE NORTHERN PLAINS
SHORT WAVE AND THE STRONGER UPPER LOW SPINNING NEAR THE COLORADO
RIVER DELTA/NORTHERN BAJA. IN FACT...IT SHOULD BE ANOTHER MOSTLY
SUNNY DAY.
LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED SATURDAY INTO EARLY
SUNDAY. HOWEVER...TEMPERATURES WILL TURN WARMER WITH SOME
MODERATION IN THE AIRMASS.
BY LATE SUNDAY AND MONDAY THE UPPER LOW OVER THE FAR SOUTHWEST IS
EXPECTED TO GRADUALLY KICK EAST/NORTHEAST AS A WEAK UPSTREAM KICKER
MOVES INTO THE PACIFIC NORTHWEST. THE CHANCE OF ANY PRECIPITATION
AT THIS POINT LOOKS QUITE SLIM WITH THE MAIN TROUGH BEING TOO FAR
SOUTH. THE NORTHERN SYSTEM WILL ALSO BE QUITE WEAK...SO ANY MENTION
OF SNOW IN THE FORECAST WILL BE LIMITED TO THE MOUNTAINS FOR NOW.
AVIATION...VFR CONDITIONS TO PREVAIL THROUGH THURSDAY MORNING. LOW
CLOUDS AND FOG ARE EXPECTED TO REMAIN EAST OF THE DENVER AREA
AIRPORTS. LIGHT DRAINAGE WINDS WILL CONTINUE EARLY THIS MORNING
TRANSITIONING TO WEST AND NORTHWEST WINDS MIDMORNING...INCREASING
AFTER 15Z AS DOWNSLOPE WINDS PREVAIL. CEILINGS TO REMAIN ABOVE 10000
FEET AGL THROUGH THE DAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SZOKE
LONG TERM....99
AVIATION...SZOKE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
238 PM CST WED DEC 14 2011
.DISCUSSION...
ISSUED 238 PM CST WED DEC 14 2011
SPRING-LIKE STORM SYSTEM BRINGING SHOWERS AND SCATTERED
THUNDERSTORMS TO THE CENTRAL/NORTHERN CWA TODAY IN BROAD...WARM
SOUTHWEST FLOW. HEAVIEST RAINS OF 1.5-2.5 INCHES HAVE FALLEN NORTH
OF A BEARDSTOWN TO BLOOMINGTON LINE. MODERATE RAINFALL RATES AND
UNFROZEN GROUND HAVE PRODUCED LITTLE IN THE WAY OF WATER PROBLEMS.
UPPER LEVEL DYNAMICS HELPING DRIVE THIS ACTIVITY AS SFC LOW AND
FRONT ANALYZED AT 19Z ACROSS EASTERN NEB/NRN KS. EVEN WITH THICK
CLOUDS AND RAIN...EARLY AFTERNOON TEMPS WERE RUNNING 15-20 DEGREES
ABOVE NORMAL. SHORT TERM FORECAST ISSUE IS ENDING OF RAIN WITH
COLD FRONTAL PASSAGE LATE TONIGHT AND RETURN TO SEASONABLE TEMPS.
BEYOND...NEXT MAJOR SYSTEM LOOKS TO IMPACT REGION EARLY NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY
UNSEASONABLY HIGH P/W VALUES AROUND 1.25 INCHES AND STRONG FORCING
ALOFT WILL CONTINUE TO DRIVE MODERATE RAIN AND EMBEDDED
THUNDERSTORMS THIS EVENING. LATEST HIGH RES NAM AND HRRR RUNS SHOW
ROUNDS OF CONVECTION TRANSLATING EAST ACROSS THE CWA THROUGH LATE
EVENING. PLENTY OF ELEVATED INSTABILITY FOR THUNDER...AND VERY
STRONG LLJ OVERHEAD /1 KM AGL WINDS 50 KTS/ BUT DUE TO STRONG LOW
LEVEL INVERSION DO NOT EXPECT ANY OF THIS TO MAKE IT DOWN TO THE
SURFACE. MAIN BATCH OF RAIN ASSOCIATED WITH PRE-FRONTAL TROUGH
LOOKS TO PUSH INTO INDIANA AFTER MIDNIGHT...WHEN THE ACTUAL COLD
FRONT ENTERS THE NW CWA. EXPECT A LINE OF SCATTERED SHOWERS
ALONG/AHEAD OF THE FRONT...WHICH WILL EXIT THE SE CWA AROUND 15Z
THU. BRISK WEST WINDS GUSTING TO 20-25 MPH WILL MOVE IN BEHIND THE
FRONT...BRINGING IN COOLER AND DRIER AIR.
CLOUD FORECAST FOR THURSDAY IS PROBLEMATIC WITH DRY AIR ADVECTING
IN...BUT FCST SOUNDINGS SHOW A SHALLOW LAYER OF MOISTURE TRAPPED
BENEATH A SHARP SUBSIDENCE INVERSION AROUND 925 MB. THIS COMBINED
WITH CYCLONIC FLOW ALOFT AND WEAK SUN ANGLE MAKES A LOW STRATUS
DECK LOOK LIKELY TO HOLD AT LEAST INTO MID AFTERNOON. TEMPERATURES
MAY HOLD STEADY FOR A FEW HOURS IN THE MORNING...THEN SLOWLY FALL
THROUGH THE AFTERNOON WHEN STRONGER CAA KICKS IN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
QUIET AND SEASONABLE WEATHER IS ON TAP FOR THE FRIDAY INTO SUNDAY
PERIOD. ZONAL/WNW FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL
BE RESPONSIBLE FOR THE TRANQUIL CONDITIONS. AS THE HIGH SHIFTS OFF
TO THE SOUTHEAST LATE IN THE WEEKEND SOUTHERLY FLOW DEVELOPS AHEAD
OF THE NEXT SYSTEM IN THE SW.
CURRENT INDICATIONS SHOW THIS EVENT MAY BE SIMILAR TO THE STORM
THAT IS CURRENTLY IMPACTING THE AREA. THE 12Z ECMWF AND CANADIAN GEM
ARE SIMILAR IN TRACKING A STRONG LOW FROM THE TX PANHANDLE REGION
MONDAY MORNING...INTO THE LOWER GREAT LAKES BY TUESDAY EVENING.
12Z GFS IS MUCH SLOWER AND FARTHER SOUTH AND WAS NOT FOLLOWED FOR
THIS FORECAST. EVENTUAL LOW TRACK WILL DETERMINE EXACT PRECIP TYPE
AND AMOUNTS...BUT CURRENT SOLUTION WOULD POINT TO PRIMARILY
ANOTHER MODERATE RAIN EVENT FOR THE CWA FOR SUNDAY NIGHT INTO TUESDAY.
LATER MODEL RUNS WILL NEED TO BE MONITORED...AS ECMWF DIGS A
NORTHERN STREAM WAVE INTO THE MIDWEST FOR A MORE PHASED SYSTEM AND
POTENTIAL SNOW BAND ON THE NW SIDE OF THE STORM. AFTER A BRIEF
SHOT OF COLDER AIR BEHIND THIS LOW...ZONAL FLOW LOOKS TO MODERATE
TEMPS FOR MID WEEK.
25
&&
.AVIATION...
ISSUED 1150 AM CST WED DEC 14 2011
CEILINGS BELOW 1K FT ALONG I-74 TAF SITES OF PIA...BMI AND CMI MAY
LIFT FOR A TIME THIS AFTERNOON TO MVFR ESPECIALLY AT CMI WHILE
MVFR CEILINGS EXPECTED AT SPI AND DEC WITH DEC CURRENTLY DOWN TO
1K FT BROKEN CEILING. CONTINUED RAIN SHOWERS ACROSS THE CENTRAL IL
TERMINALS THIS AFTERNOON AND EVENING WITH ISOLATED THUNDERSTORMS
POSSIBLE BUT TOO TOUGH TO PIN POINT DOWN EXACT LOCATION AND TIME.
VISIBILITIES OF 1 TO 3 MILES AT PIA AND BMI WITH RAIN AND FOG COULD
LIFT TO MVFR FOR A TIME THIS AFTERNOON. MEANWHILE CMI WILL HAVE
MVFR VSBYS AND POSSIBLY VFR AT TIMES WHILE DEC AND SPI TO SEE MVFR
VSBYS RETURN DURING THE AFTERNOON WITH RETURN OF MORE RAIN
SHOWERS FROM THE SW. 1007 MB LOW PRESSURE OVER NORTHCENTRAL KS TO
DEEPEN NE TO 1002 MB OVER EAST CENTRAL WI BY MIDNIGHT AND TO 992
MB OVER SW QUEBEC BY 18Z/NOON THU. THIS TO SWING A COLD FRONT SE
THROUGH CENTRAL IL LATER TONIGHT...REACHING PIA BY 09Z AND CMI BY
12Z. SHOWERS END AFTER FRONTAL PASSAGE AS STRONG SOUTH WINDS WITH
GUSTS INCREASING TO 23-28 KTS DURING THIS AFTERNOON...TURN W/NW
BEHIND THE FRONT LATE TONIGHT AND THU MORNING. CONTINUE BROKEN TO
OVERCAST CEILINGS OF 1-2K FT BEHIND THE COLD FRONT THU MORNING AS
VFR VISBILITIES ARRIVE WITH FOG LIFTING.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
418 PM EST WED DEC 14 2011
.SHORT TERM...
TONIGHT THROUGH THURSDAY NIGHT...
KIWX RADAR DEPICTING BAND OF MOD/HVY RAIN ALONG/AHEAD OF WARM FRONT
LIFTING NORTH THROUGH THE AREA THIS AFTERNOON. THIS IS IN
ASSOCIATION WITH DEVELOPING SFC LOW IN CENTRAL PLAINS. WATER VAPOR
IMAGERY AND LATEST RUC ANALYSIS SHOWING LEAD SHORT WAVE EJECTING OUT
OF FOUR CORNERS AND WILL COMBINE WITH COUPLED JET STRUCTURE FROM
NORTHERN GREAT LAKES DOWN INTO THE CENTRAL PLAINS TO DEEPEN SFC LOW
AND DRIVE IT INTO WESTERN GREAT LAKES THIS EVENING. THIS WILL
PLACE THE FCST AREA IN ENHANCED MOIST SOUTHERLY FLOW IN THE WARM
SECTOR AND SUPPORT ANOTHER ROUND OF PRECIPITATION TONIGHT. COLD
FRONT WILL MOVE THROUGH THE AREA ON THURSDAY AND BRING AN END TO
RAIN BY 18Z. SIGNIFICANT DRYING BEHIND THE FRONT ALONG WITH MARGINAL
DELTA T WILL PROVIDE LITTLE SUPPORT FOR LES IN THE WAKE OF THIS
SYSTEM SO FAVOR CURRENT GRIDS IN KEEPING JUST A MENTION OF FLURRIES
ATTM. FIRST TWO PERIODS OF FCST WILL FEATURE NON-DIURNAL TEMP
PATTERN AS WARM FRONT LIFTING NORTH OF THE AREA TONIGHT WILL KEEP
TEMPS STEADY/SLOWLY RISING...THEN CAA BEHIND PASSAGE OF COLD FRONT
THURSDAY WILL SEE HIGHS REACHED IN THE MORNING FOLLOWED BY FALLING
TEMPS IN THE AFTERNOON. COOLER BUT SEASONABLE TEMPS THURSDAY NIGHT
WITH LOWS IN THE MID-UPPER 20S.
&&
.LONG TERM...
FRIDAY THROUGH WEDNESDAY
ACTIVE NORTHERN STREAM WILL INFLUENCE LOWER HEIGHTS INTO THE REGION
THIS WEEKEND WITH COLDER/DRIER AIR PUSHING INTO THE GREAT LAKES...AS
PERIPHERY DISTURBANCES ADVECT THROUGH THE FLOW. A SERIES OF THESE
WEAK INFLUENCES MAY INFLUENCE ENOUGH LIFT AND COLUMN SATURATION TO
SUPPORT LIGHT SNOW OR FLURRIES ACROSS THE NORTH...ALONG WITH A WEAK
LAKE RESPONSE. OTHERWISE...MODELS AND ENSEMBLES CONTINUE TO SUPPORT
THE EJECTION OF A SW CONUS DISTURBANCE INTO THE REGION BY EARLY NEXT
WEEK...WITH SOME RATHER SIG DISCREPANCIES AMONG DETERMINISTIC
SOLUTIONS. WILL STAY THE COURSE WITH PERSISTENCE...FAVORING THE
WARMER ECMWF AND GEM. THIS WILL ESP BE TRUE IF FLOW PHASING IS
REALIZED...WHICH IS CERTAINLY POSSIBLE GIVEN THE PATTERN. SMALL
ADJUSTMENT MADE TO THE PREVIOUS FORECAST...GENERALLY TO POPS/WX.
FRI-SUN...OVERALL DRY/SLIGHTLY DISTURBED FLOW WILL REMAIN IN THE
GREAT LAKES REGION. CONTINUED TO OPT NOT TO INCLUDE A LAKE EFFECT
SNOW SHOWER MENTION FRI-SAT FAR NW GIVEN MARGINAL SUPPORT FOR LAKE
INDUCE CONVECTION...WITH ONLY A FLURRY MENTION ATTM...SPREAD OVER
THE ENTIRE NORTH TO COVER THE POTENTIAL FOR LIGHT SNOW WITH ANY OF
THE WEAK DISTURBANCES. PROFILES INDICATE SIG DRYING IN THE SFC TO H8
LAYER WITH MARGINAL DELTA T/S PRESENT. CANNOT RULE OUT A FEW
FLURRIES OR LIGHT LAKE EFFECT SNOW SHOWERS IF COLDER PROFILES
VERIFY...COUPLED WITH A WEAK NORTHERN STREAM DISTURBANCE PROGGED
INTO THE REGION...WHICH COULD GENERATE ENOUGH INVERSION HEIGHT
UNDULATION TO SUPPORT PERHAPS A FEW SNOW SHOWERS/FLURRIES IN SHORT
FETCH WESTERLY FLOW. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN AROUND
NORMAL TO SLIGHTLY ABOVE IN THE PERIOD...WITH LAKE EFFECT CLOUDS
ACROSS NORTHERN AREAS LINGERING THROUGH SAT.
MON-WED...CHANCES FOR A DECENT STORM SYSTEM CONTINUE...AS AN ACTIVE
NORTHERN STREAM IMPULSE LIKELY INTERACTS WITH ANOTHER SW CONUS
UPPER LOW. ADVECTION TIMING/THERMAL FIELDS/AND HEIGHT FALL DEPTH
INTO THE REGION IS STILL MUCH UNCERTAIN...BUT GIVEN THE GFS/S
TENDENCY TOWARD PROGRESSIVE FLOW...LIKELY BIASING THE NAEFS
SOLUTIONS...HAVE CONTINUED TO SIDE TOWARD THE MORE RELIABLE ECMWF. A
TREND TO A DEEPER H5 SOLUTION WOULD CERTAINLY BE NEEDED...ESP IF
WAVE PHASING RESULTS...WITH COUPLED JET DYNAMICS LIKELY SHIFTING THE
SFC LOW TRACK NW OF THE FA...AS SEEN IN THE GEM. RETAINED A
RAIN/SNOW MENTION IN MOST PERIODS...MAINLY TO COVER
UNCERTAINTY...BUT IT CERTAINLY LOOKS LIKE RAIN WILL BE THE DOMINATE
WEATHER TYPE IN THE PERIOD...ESP SE HALF. CONTINUE TO EXPECT MORE
ADJUSTMENT IN THIS PERIOD.
&&
.AVIATION.../18Z TAFS/
KIWX RADAR INDICATING BAND OF MODERATE TO HEAVY RAIN IMPACTING KSBN
ATTM AND IS EXPECTED TO ARRIVE AT KFWA BETWEEN 19-20Z THIS AFTERNOON
KEEPING IFR CONDITIONS OVER THE AREA THROUGH MUCH OF THE TAF PERIOD.
LOW PRESSURE WILL TRACK UP INTO THE WESTERN GREAT LAKES THIS EVENING
KEEPING GUSTY S/SW FLOW AND LLWS AT BOTH TAF SITES INTO THE EARLY
MORNING HOURS THURSDAY. COLD FRONT WILL MOVE THROUGH THURSDAY
MORNING AND BRING AN END TO THE RAIN BUT LOW LEVEL MOISTURE WILL
KEEP IFR/MFVR CIGS OVER THE AREA THROUGH THE END OF THE TAF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH THROUGH THURSDAY EVENING FOR LMZ043-046.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JC
AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1143 AM EST WED DEC 14 2011
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
RAIN SHOWERS WILL IMPACT THE REGION THROUGH EARLY THURSDAY AS FIRST
A WARM FRONT THEN A COLD FRONT PASS THROUGH THE OHIO VALLEY. IN THE
WAKE OF THIS FRONT...HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH
THE WEEKEND. A LOW PRESSURE SYSTEM MAY APPROACH THE AREA FROM THE
SOUTHWEST EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
FORECAST CHALLENGES FOR THIS AFTERNOON INCLUDE TEMPERATURES AND
HOW TO HANDLE POPS. A DECENT STRATUS LAYER HAS LINGERED ACROSS
THE REGION HINDERING AN INCREASE IN TEMPERATURES...MAINLY ACROSS
THE NORTHERN HALF. THEREFORE...DECREASED HIGHS 2-3 DEGREES ACROSS
THIS AREA SINCE IT WILL ALSO BE THE FOCUS FOR ANY AFTERNOON
SHOWERS WHICH WILL CONTINUE TO INHIBIT WARMING. TEMPERATURES
ACROSS THE SOUTH APPEAR TO BE ON TRACK AND RISING AS EXPECTED SO
DID NOT MESS WITH THE PREVIOUS FORECAST.
SIGNIFICANTLY CUT POPS ACROSS THE CENTRAL PORTION OF THE FORECAST
AREA AND COMPLETELY REMOVED ANY PRECIPITATION MENTION FOR THE SOUTH
AND EAST BEFORE 21Z. THE LATEST RUC AND HRRR DATA DEPICT RAINFALL
SHOULD REMAIN OUT OF THIS AREA FOR MOST OF THE NEAR TERM. ON THE
OTHER HAND...CONTINUED LIKELY POPS ACROSS THE EXTREME NORTHWEST AS
CURRENT RADAR TRENDS INDICATE THE MAIN PRECIPITATION SHIELD MOVING
INTO THE NORTHWEST QUADRANT OF THE STATE. REGARDING THUNDER
MENTION...WITHOUT ANY REAL INSTABILITY...LEFT ANY MENTION OUT OF
THE GRIDS PRIOR TO 21Z. LEFT SLIGHT CHANCE WORDING IN THE
NORTHWEST AS LATEST MODELS SOUNDINGS INDICATE SOME ELEVATED
CONVECTION CANNOT BE COMPLETELY RULED OUT.
LASTLY...DECREASED WINDS THROUGHOUT THE NEAR TERM. EVEN WITH A
DECENT PRESSURE GRADIENT ACROSS THE AREA...OBSERVATIONS AND
LATEST GUIDANCE INDICATE WINDS WILL BE MORE IN THE 10-15 KT RANGE
THIS AFTERNOON AS COMPARED TO 15-20 KTS...OR HIGHER...AS INDICATED
PREVIOUSLY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
BREAK IN RAIN WILL BE SHORT LIVED AS THE AFFECTS OF THE APPROACHING
EJECTING LOW AND SURFACE COLD FRONT BEGIN MOVING INTO THE NORTHWEST
ZONES LATER THIS AFTERNOON AND THROUGH EVENING. MODELS REMAIN IN
GOOD AGREEMENT WITH THIS FEATURE AND ARE ACTUALLY EVEN MORE
PROGRESSIVE THAN PREVIOUS MODEL RUNS. 850 MB JET LOOKS EVEN STRONGER
THIS RUN AROUND 60 KTS ACROSS CENTRAL INDIANA BY 06Z. LOOK FOR GUSTY
WINDS AROUND 35 TO 40 MPH. WILL CONTINUE TO GO WITH 100% POPS...AND
A CHANCE FOR THUNDERSTORMS TO ACCOUNT FOR THE ELEVATED INSTABILITY.
WE ARE NOT IN A RISK FOR SEVERE WX.
AS JUST MENTIONED...MODELS ARE MORE PROGRESSIVE WITH THE
FRONT...BASICALLY CLEARING IT OF THE FORECAST ARE BY LATE THU MORN.
THINK THIS MIGHT BE A LITTLE TOO FAST BASED ON PAST EVENTS...SO WENT
WITH A SLIGHTLY SLOWER FROPA TIMING...REDUCING CHANCES FROM NW TO SE
THROUGHOUT THE DAY THU. IT DOES APPEAR THAT THE BULK OF THE RAIN
WILL BE OVER BY LATE THU MORNING FOR LOCATIONS NORTH OF I-70...WITH
THE REST TO THE AREA TO FOLLOW SHORTLY THEREAFTER.
TEMPERATURE FORECAST IS OF COURSE TRICKY...DEPENDING ON THE EXACT
POSITION OF THE FRONT. SINCE THIS MODELS WERE MORE PROGRESSIVE THIS
ROUND...DROPPED HIGHS ACROSS THE NW COUNTIES SLIGHTLY DURING THE DAY
THU.
HIGH PRESSURE BUILDS IN POST FROPA. LOOK FOR A RETURN TO COOLER AND
DRY WX.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FAIRLY WIDE DISCREPANCY IN GUIDANCE WITH HANDLING OF NEXT
SIGNIFICANT WEATHER MAKER IN THE LONG TERM PERIOD...LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. HOWEVER...THERE REMAINS A GENERAL
CONSENSUS IN FORMATION OF A LOW PRESSURE SYSTEM TO OUR
WEST/SOUTHWEST LATE IN THE WEEKEND WHICH THEN PUSHES INTO THE
REGION LATE SUNDAY NIGHT THROUGH TUESDAY NIGHT...AND ALLBLEND POPS
REFLECT THIS WELL.
GIVEN ANTICIPATED UPPER LEVEL PATTERN...TEMPS LOOK REASONABLE AS
WELL. SEE NO REASON TO DEVIATE FROM ALLBLEND WITH SIGNIFICANT
DISCREPANCIES IN GUIDANCE.
&&
.AVIATION /UPDATE FOR 141530Z TAFS/...
PREVIOUS DISCUSSION SUMMARIZES SITUATION WELL. AS IT INDICATES...
FREQUENT UPDATING WILL BE NEEDED TODAY. THE PREVIOUS DISCUSSION
FOLLOWS.
POOR FLYING CONDITIONS THROUGH THE PERIOD AS AMPLE LOW LEVEL
MOISTURE STREAMS ACROSS THE AREA AHEAD OF DEVELOPING LOW PRESSURE TO
THE WEST.
ALL SITES IFR IN ONE MANNER OR ANOTHER...MOST WITH BOTH CEILINGS AND
VISIBILITIES. SHOULD SEE SOME IMPROVEMENT DURING THE COURSE OF THE
DAY...MORE LIKELY AT IND/BMG AS IT APPEARS THESE SITES WILL BE A BIT
NEARER THE EDGE OF THE WIDESPREAD IFR TO OUR WEST.
THAT SAID...FLUCTUATIONS ARE LIKELY AND CONFIDENCE IS LOW IN THE
EXACT DETAILS OF THE FORECAST...ALTHOUGH RELATIVELY HIGH IN SOME
MANNER OF RESTRICTION THROUGH MUCH OF THE PERIOD.
WILL BE A LULL IN PRECIP THROUGH MUCH OF TODAY WITH ADDITIONAL RAIN
MOVING IN THIS EVENING. THUNDER CANNOT BE RULED OUT...BUT REMAINS
LOW PROBABILITY AND WILL BE LEFT OUT AT THIS TIME.
WINDS WILL INCREASE TO AROUND 15KT LATER TODAY AND REMAIN RELATIVELY
STRONG THROUGHOUT. A FEW GUSTS CANNOT BE RULED OUT THIS
AFTERNOON...BUT FEEL THAT CLOUD COVER WILL HELP TO SUPPRESS THIS
SOMEWHAT. GUSTS WOULD ONLY BE TO AROUND 20-25KT.
LATER TONIGHT...A STRONG LOW LEVEL JET /50-60KT/ WILL ACCOMPANY THE
COLD FRONT AS IT APPROACHES. WILL INCLUDE LOW LEVEL WIND SHEAR AS
MOMENTUM TRANSFER PROGS INDICATE LITTLE GUSTINESS OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...HOMANN/CP
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...JK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
554 PM CST THU DEC 15 2011
.AVIATION...
CURRENTLY....VFR CEILINGS AROUND 3200FT AT ALL TAF SITES. HIGH
PRESSURE DROPPING SOUTHWARD WILL BRING COLD AND DRIER INTO THE
REGION HELPING TO SCOUR OUT THE STRATUS WITH ALL TAF SITES IN VFR
WITH NO CLOUDS BY 06 UTC. THERE IS A RISK BEFORE THE CLOUDS CLEAR
THAT THEY WILL DROP TO MVFR FOR A COUPLE OF HOURS. THE SITE MOST
LIKELY TO DO THIS IS KDBQ. ANOTHER STORM SYSTEM PASSES TO THE
NORTH OF THE REGION ON FRIDAY AFTERNOON WITH VFR CEILINGS MOVING
INTO THE REGION AFTER 2000 UTC. DC/LE
&&
.PREV DISCUSSION... /ISSUED 244 PM CST THU DEC 15 2011/
SYNOPSIS...
12Z UA ANALYSIS HAS A LLJ RUNNING FROM OKLAHOMA INTO NEW ENGLAND.
SEVERAL TROFS RAN FROM THE WESTERN GREAT LAKES INTO THE NORTHERN
PLAINS WHERE ANOTHER LLJ WAS LOCATED. SATELLITE TRENDS THROUGH EARLY
AFTERNOON SHOW THE CLOUDS BEGINNING TO BREAK UP AS STRONG SUBSIDENCE
DEVELOPS ACROSS THE PLAINS AND UPPER MISSISSIPPI VALLEY.
18Z SFC ANALYSIS HAS THE COLD FRONT FROM LAKE HURON INTO EASTERN
TEXAS WITH HIGH PRESSURE IN THE PLAINS. SEVERAL TROFS RAN FROM THE
WESTERN LAKES INTO THE UPPER MISSISSIPPI VALLEY. DEW POINTS AHEAD OF
THE FRONT WERE IN THE 50S AND 60S WITH 30S AND 40S IMMEDIATELY
BEHIND THE FRONT. DEW POINTS IN THE TEENS AND 20S WERE IN THE PLAINS
AND PARTS OF THE MIDWEST.
SHORT TERM...TONIGHT AND FRIDAY...
QUIET WX WITH SEASONABLE TEMPERATURES WILL BE SEEN TONIGHT AND
FRIDAY. WINDS WILL CONTINUE TO DECREASE LATE THIS AFTERNOON AND
EVENING AS THE STRONGEST ISALLOBARIC CHANGE CONTINUES TO MOVE EAST
OF THE AREA. RUC TRENDS INDICATE THAT STRONG SUBSIDENCE IS
DEVELOPING BEHIND THE DEPARTING SHORTWAVE AND SATELLITE DOES SHOW
MORE BREAKS BEGINNING TO DEVELOP IN THE CLOUD SHIELD.
BASED ON CURRENT SATELLITE AND RUC TRENDS...CLOUDS WILL CONTINUE TO
SLOWLY BREAK UP FOR THE REMAINDER OF THE AFTERNOON WITH CLEARING
DEVELOPING ACROSS THE CWFA LATE THIS AFTERNOON OR EVENING.
.08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
A WEAK CLIPPER SHOULD SLIDE SOUTHEAST FRIDAY EVENING...BRINGING SOME
MID CLOUDS TO THE CWA...AND AN OUTSIDE CHANCE FOR A SNOW
SHOWER...BUT MORE LIKELY FLURRIES IN THE NORTH. THIS VERY MINOR
EVENT PASSES QUICKLY FRIDAY NIGHT AND LEAVES SATURDAY AND SUNDAY
WITH VERY PLEASANT LATE FALL WEATHER. HIGHS IN THE MID TO UPPER 30S
SATURDAY AND LOWER TO MID 40S SUNDAY. THIS ENDS THE PERIOD OF HIGH
CONFIDENCE IN THE EXTENDED.
THE MODELS ARE IN TWO CAMPS NOW WITH RESPECT TO THE MONDAY THROUGH
WEDNESDAY STORM. THE GEM...UKMET...AND GFS RUNS SINCE 00Z LAST NIGHT
HAVE GONE FARTHER NORTH...AND BRING A SIMILAR STORM TO THE MIDWEST
THAN WAS SEEN IN THE PAST 2 DAYS. HOWEVER...THE ECMWF HAS TRENDED
SOUTH...AND CLIPS THE CWA WITH LIGHT SNOW ON TUESDAY/TUESDAY NIGHT.
THE MAJOR DIFFERENCE BETWEEN THESE MODELS BOILS DOWN TO HOW THEY
HANDLE A SEPARATE SHORT WAVE THAT ENTERS THE PACIFIC NORTHWEST
SATURDAY. THE GEM/UK/GFS ALL BRING THAT STORM INTO THE WA/OR
COAST...AND PHASE THAT WAVE/KICK THE CLOSED LOW NORTHEASTWARD AND
THEREFORE DEVELOP A SIGNIFICANT MIDWEST STORM. THE ECMWF BRINGS THIS
WAVE INTO CENTRAL BRITISH COLUMBIA...AND AS IT MOVES IT EAST...IT
OVER TOPS THE RIDGE ON THE WEST COAST VS KICKING THE LOW OUT WITH
IT. AFTER OVERTOPPING...IT SWEEPS HIGH PRESSURE AND COLD AIR DOWN
INTO THE MIDWEST FOR EARLY WEEK AND THEREFORE SUPPRESSES THE STORM
SYSTEM SOUTH. SUCH A SMALL DIFFERENCE...RESULTS IN A MAJOR
DIFFERENCES IN OUR WEATHER. THIS WAVE IN QUESTION IS REAL...BUT
FOUND OVER THE NORTH CENTRAL PACIFIC OCEAN AS OF NOW...AND IS WITHIN
A FAST BAND OF WESTERLY FLOW SOUTH OF A MAJOR ALEUTIAN LOW.
THUS...GLOBAL MODELS WILL NO LIKELY LOCK CORRECTLY ONTO ITS POSITION
AND STRENGTH FOR SOME DAYS. PREDICTING THE WEATHER IS A
CHALLENGE...BUT THIS ONE WILL TAKE TIME TO BE WORKED OUT. UNTIL WE
KNOW FOR SURE WHAT LATITUDE THIS WAVE MAKES LANDFALL IN THE PAC
NORTHWEST...WE WILL NO KNOW WHETHER IT OVERTOPS OR PHASES/KICKS OUT
OUR CLOSED LOW IN THE SOUTHWEST. TIME WILL CERTAINLY TELL.
OUR FORECAST REMAINS WET TO START...AND SNOWY TO END THIS
STORM...POPS ARE LOW...BUT SHOULD THE NORTHERN TRACK BY CORRECT...WE
NEED MUCH HIGHER POPS FOR THIS EVENT.
WEDNESDAY AND THURSDAY...ALL GLOBAL MODELS SHOW THE PATTERN
RELOADING FOR ANOTHER CUT OFF LOW IN THE SOUTHWEST. THIS SHOULD
PROVIDE ANOTHER DAY OR TWO OF QUIET WEATHER BEFORE ANOTHER POTENTIAL
EVENT.
.ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
319 PM CST WED DEC 14 2011
.SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB WARM FRONT FROM SOUTH DAKOTA INTO
SOUTHERN WISCONSIN. A LLJ RAN FROM THE WESTERN GREAT LAKES TO NORTH
TEXAS WITH THE STRONG CORE OF 50-55 KNOTS FROM EASTERN KANSAS INTO
NORTH TEXAS. A STRONG MOISTURE FEED RAN FROM THE GULF COAST INTO THE
WESTERN GREAT LAKES. RADAR TRENDS SHOW THE CONVECTION AND
THUNDERSTORMS HAVE SHIFTED INTO EASTERN ILLINOIS WITH PRECIPITATION
INTENSITY DECREASING ACROSS IOWA AND MISSOURI.
18Z SFC ANALYSIS HAD A WEAK LOW NEAR KLNK WITH A WARM FRONT ALONG
THE IA/MO BORDER INTO CENTRAL ILLINOIS. A COLD FRONT RAN FROM THE
LOW BACK INTO SOUTHEAST COLORADO. DEW POINTS SOUTH OF THE WARM FRONT
WERE IN THE 50S AND 60S.
&&
.SHORT TERM...TONIGHT AND THURSDAY...
THE RUC HAS BEEN DOING A REASONABLE JOB OF HANDLING THE IMMEDIATE
SHORT TERM AND THE TRENDS OF THE RUC WERE FOLLOWED FOR INPUT TONIGHT.
THE LIFT TOOL INDICATES THE THREAT OF THUNDER IS NOW OVER WITH THE
PASSAGE OF A STRONG VORT MAX. OVERALL PRECIPITATION INTENSITY WILL
NOW BE LIGHT DURING THE EVENING HOURS WITH EVERYTHING TRANSITIONING
TO MORE DRIZZLE WITH TIME. THUS DRIZZLE WITH SOME RAIN WILL BE SEEN
DURING THE EVENING HOURS ALONG WITH PATCHY FOG. AFTER MIDNIGHT...
CONDENSATION PRESSURE DEFICITS SLOWLY RISE IN THE WEST WITH THE
BETTER FORCING SHIFTING EAST OF THE MISSISSIPPI. THE RUC DOES SHOW
ANOTHER ROUND OF FORCING ARRIVING AROUND MIDNIGHT IN THE WESTERN
CWFA. THUS WILL CONTINUE THE DRIZZLE WITH OVERALL LOWER CHANCES OF
RAIN. PATCHY FOG WILL STILL BE AN ISSUE AFTER MIDNIGHT.
THE OVERALL DENSE FOG IS PATCHY IN NATURE AND GENERALLY CONFINED TO
THE HWY 20 CORRIDOR. THE MORE WIDESPREAD AND LIKELY DENSE FOG SHOULD
BE SEEN ACROSS WISCONSIN AND MINNESOTA WHERE THE SFC LOW TRACKS.
THE COLD FRONT WILL MOVE THROUGH THE CWFA AFTER MIDNIGHT. WINDS
SHOULD REMAIN UP WHICH WILL KEEP THE FOG FROM GETTING TOO DENSE AS
THE OVERALL ATMOSPHERIC COLUMN COOLS. LOW TEMPERATURES SHOULD OCCUR
BETWEEN 7 AND 9 AM THURSDAY MORNING.
THURSDAY...THERE MAY OR MAY NOT BE SOME LINGERING DRIZZLE ACROSS THE
EASTERN CWFA EARLY IN THE MORNING. CONDENSATION PRESSURE DEFICITS
CONTINUE TO RISE AND NO FORCING IS PRESENT. HOWEVER...FORECAST
SOUNDINGS DO SHOW CONSIDERABLE DRYING ABOVE THE LOW CLOUDS SO SOME
DRIZZLE MAY BE POSSIBLE. CLEARING WILL BE SLOW TO OCCUR DURING THE
MORNING. AS HIGH PRESSURE BEGINS BUILDING IN BY MID DAY A GENERAL
CLEARING OF SKIES SHOULD BE SEEN FROM WEST TO EAST DURING THE
AFTERNOON. MAX TEMPERATURES WILL OCCUR BETWEEN 7 AND 9 AM THURSDAY
MORNING WITH TEMPERATURES SLOWLY FALLING THROUGH THE DAY.
..08..
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...THE LONG TERM
BEGINS WITH A BRIEF COOL DOWN IN THE WAKE OF OUR CURRENT
STORM...THEN AFTER ABOUT 48 HOURS OF NORTHWEST FLOW...WE BEGIN TO
TREND TOWARD ANOTHER POTENTIAL SIGNIFICANT STORM SYSTEM FOR SUNDAY
NIGHT THROUGH TUESDAY.
MOISTURE WILL BE STARVED...BUT SOME POSSIBLE FLURRIES OR BRIEF LIGHT
SNOW COULD OCCUR SATURDAY AFTERNOON IN THE FAR NORTH AS SHEARED OUT
SHORT WAVE ARRIVES FROM THE NORTHWEST. THIS LOOKS TO MAIN PRODUCE
MID CLOUDS DURING THE AFTERNOON AND EVENING HOURS SATURDAY.
TEMPERATURES WILL BE COOL...BUT NOT COLD. WITH LOWS IN THE LOWER TO
MID 20S...AND HIGHS GENERALLY IN THE LOWER TO UPPER 30S.
SUNDAY...THERE BEGINS TO BE ANOTHER CHANGE TOWARD AN ACTIVE STORM
SYSTEM. THERE ARE MAJOR DIFFERENCES IN THE POSITION OF A NORTHWEST
FLOW WAVE THAT MAKES LANDFALL ON EITHER THE SOUTHWEST CANADIAN
COAST/BRITISH COLUMBIA...OR NORTHWESTERN CONUS. THIS SMALL
DIFFERENCE IN MODELS GREATLY INFLUENCED THE AMOUNT OF PHASING OF THE
UPPER LOW WHICH SHOULD BE CUT OFF IN THE SOUTHWEST CONUS AT THAT
TIME. THE UKMET...GEM...AND ECMWF CONTINUE TO SHOW THE NORTHWEST
FLOW WAVE HITTING THE WA/OR COASTLINE THEN DRAWING THE CUT OFF LOW
NORTHEAST SUNDAY NIGHT. THE GFS MAKES A MORE NORTHERLY ENTRY INTO
CENTRAL BRITISH COLUMBIA WITH THE NORTHWESTERN SHORT
WAVE...THUS...IT IS DELAYED BY 24 HOURS ON PHASING WITH THE LOW IN
THE SOUTHWEST...AND LESS SO AT THAT. THUS...FOR THAT REASON
ALONE...THE GFS REMAINS FAR SOUTH OF OTHER GLOBAL MODELS...AS WELL
AS SLOWER. THE CURRENT STORM OVERHEAD WAS ALSO FORECAST BY THE GFS
TO BE FARTHER SOUTH WHEN IT WAS OUT IN THIS DAY 6 PERIOD FOR SIMILAR
REASONS...AND THEREFORE WHEN COMBINED WITH THE FACT THAT THERE IS
LITTLE OR NO SNOW COVER IN THE MIDWEST AND THERE IS NO ARCTIC AIR IN
PLACE TO KEEP A SYSTEM SOUTH...I BELIEVE IN A MORE PHASED NORTHERLY
SOLUTION. THIS POTENTIAL STORM LOOKS TO HAVE ANOTHER OPEN GULF...AND
MODEST TO STRONG UPPER FORCING. THUS...SHOULD IT OCCUR...ANOTHER
ROUND OF MODERATE RAIN IS LIKELY.
SNOW MAY OCCUR ON THE BACKSIDE PENDING THE SPEED OF THE SYSTEM AND
ABILITY TO DYNAMICALLY COOL THE ATMOSPHERE. THERE IS LITTLE
CONFIDENCE IN THAT PROCESS AT THIS TIME...BUT ENOUGH TO WARRANT
INCLUDING A RAIN OR SNOW FORECAST FOR THE NORTHWEST HALF MONDAY
NIGHT. TUESDAY MAY SEE SNOW...BUT THAT WILL DEPEND GREATLY ON THIS
SYSTEM REMAINING CLOSED AT MID LEVELS. WEDNESDAY OF NEXT WEEK
APPEARS DRY AND SEASONALLY COOL.
..ERVIN..
&&
.AVIATION...
IFR TO LIFR CONDITIONS WILL CONTINUE THROUGH 12Z/15. THE PASSAGE OF
A SHORTWAVE ALOFT HAS ENDED THE TS THREAT FOR KMLI/KBRL. WINDS
SHOULD REMAIN UP TO PREVENT VSBYS FROM DROPPING BLO 3SM BUT BRIEF
INCURSIONS BLO 3SM WILL BE POSSIBLE. OVERALL CONDITIONS WILL IMPROVE
TO MVFR AFT 12Z/15 WITH CONDITIONS IMPROVING TO VFR AFT 18Z/15.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
955 PM EST THU DEC 15 2011
...Forecast Update...
The cold front has pushed east of our area and cold air is rushing
in behind it. The 23Z HRRR seems to have the best handle on the
cold air intrusion this evening so have nudged the going forecast in
that direction resulting in low temperatures a few degrees cooler
than previously forecast.
As for precipitation, the upper level trough over New Mexico
continues to kick up moisture from TX to KY. The moisture over KY
is battling the intrusion of a much drier air mass behind the front,
thus, precip has mostly been in the form of drizzle with isolated
light rain near the KY/TN border. Have updated the forecast to
mention drizzle mainly before 2 AM EST. Overnight, south central
KY should moisten up as the trough gets closer resulting in mostly
light rain toward sunrise.
&&
.Short Term (Tonight and Friday)...
Cold front is working its way south and east across southern
Indiana, with the radar fine line and wind shift having gone through
Seymour and Jasper as of 19Z. Precip is now along and south of the
Parkways in Kentucky, and has become quite light. Upper-level
shortwave trof has ejected out of the broader low over the Desert
Southwest, and will open up and move quickly ENE.
Front should cross the Ohio River shortly before sunset, then
continue to work its way across Kentucky this evening. Cannot rule
out a brief spit of rain with the front, but expect dry weather
behind the front. Strong cold advection will allow temps to
free-fall tonight, with the progression of the front as the main
determining factor in how cold Fri morning lows will be. Skies will
remain mostly cloudy if not overcast, due to plenty of post-frontal
stratus, and the approaching upper-level impulse that will deepen
the clouds over southern Kentucky.
The upper disturbance will shear out as it crosses the Tennessee
Valley Friday, but will have just enough isentropic lift and
moisture to generate precip over southern Kentucky. Went with likely
POPs across the southern tier, as it looks like a high-probability,
low-QPF event there. Areas north of the Parkways will remain dry,
but mostly cloudy and chilly. Temperatures will struggle into the
lower to mid 40s Friday afternoon, and GFS/NAM guidance numbers are
in uncanny agreement. If the precip is heavier than anticipated, the
coolest temperatures may be found along the Tennessee border.
.Long Term (Friday Night - Thursday)...
Surface high pressure will build across the region with northwest
flow aloft through the weekend. Expect dry conditions and slowly
warming temperatures as surface winds transition to southwesterly by
Sunday. Highs Saturday in the low to mid 40s will give way to mid
and upper 40s Sunday. Overnight lows will be rather cold under
clear/mostly clear skies, with readings in the mid and upper 20s
expected.
Temperatures will continue to warm as we head into the new work week
with the development of a southern Plains surface low. Highs on
Monday and Tuesday should warm into the upper 40s and low 50s, with
lows each night in the upper 30s and low 40s. This is in response to
a cut-off upper-level low finally ejecting out of the desert
southwest. At the same time, surface low associated with a northern
stream wave will drag a cold front across the lower Great Lakes to
to the eastern Plains. The return of southerly flow will begin to
allow deeper moisture to pool along the stalled boundary with
isentropic lift the main focus for precipitation across southern
Indiana and north central Kentucky Monday afternoon and night. The
best chances for rain will not arrive until Tuesday and Tuesday
night as the southern stream system rides northeast along the
stalled frontal boundary with the surface reflection looking to pass
just northwest of the CWA.
Expect likely to categorical POPs will be needed with subsequent
forecast packages, although models are still having trouble
resolving timing differences so will keep high chance until more
confidence in specific timing can be gained. Continued the trend of
a slower solution, most consistently represented by the 15/12Z
GFS/GEM. The ECMWF continues to be inconsistent and has been the
extreme on the fast and slow sides of the guidance envelope with the
past two 00z runs. The latest 12Z run appears to have come more in
line with GFS/GEM timing.
Trough axis and low level moisture should be exiting quickly to the
east on Wednesday with only slight chances for precipitation. Will
have to watch and see how quickly cold air makes it in behind the
system although at this point continue to only call for rain. A dry
forecast returns for Thursday as surface high pressure and weak
ridging aloft take back over.
&&
.Aviation (00Z TAF Issuance)...
The cold front making its way across the region today had made it
through SDF and FFT and was sitting on the doorsteps of BWG and LEX
as of 23Z. Expect winds to shift to the NW at BWG/LEX within the
next hour. As the front passes, MVFR clouds should fill back in at
SDF/LEX according to the 18Z NAM12 H925 field. BWG will likely keep
VFR CIGS through the rest of the evening until rains arrive during
the early morning hours. Winds will continue to veer overnight
reaching a more northerly direction just before sunrise.
An upper level impulse and isentropic lift were producing rains from
TX to west TN this evening. This complex will continue to push NE
just north of the sfc frontal boundary. This will result in rain
arriving at BWG during the overnight hours with MVFR CIGS returning.
Rains should stick around BWG through the afternoon hours
Friday. Think that SDF should stay south of this system with LEX
on the fringes. Therefore did input VCSH at LEX starting at 15Z but
this may need to be adjusted depending on radar trends tonight.
MVFR CIGS will improve to VFR during the early morning hours at
SDF/LEX (around 8-10Z). MVFR CIGS will stick around at BWG through
much of the day Friday but improve as the rains move out.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......RAS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1015 PM EST THU DEC 15 2011
.SYNOPSIS...
THE UNSEASONABLE WARM TEMPERATURES WILL COME TO AN END AS COLDER
AIR FILTERS IN BEHIND THE FRONT EXITING THE REGION OVERNIGHT. A
FEW RAIN AND SNOW SHOWERS MAY DEVELOP ALONG THE RIDGES AND OVER
NORTHWEST PENNSYLVANIA BEFORE HIGH PRESSURE BUILDS IN FOR THE REST
OF FRIDAY. ANOTHER SYSTEM MAY BRING THE CHANCE FOR SCATTERED SNOW
SHOWERS SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
COLD FRONT HAS ALMOST COMPLETELY EXITED THE CWA AS OF THE 03Z
UPDATE. MADE ADJUSTMENTS TO POPS TO REFLECT THIS AND KEPT CHANCE
POPS OVER THE RIDGES AND NORTHWEST PA FOR A FEW HOURS OVERNIGHT AS
THE SECONDARY COLD FRONT/SHORTWAVE ALOFT PUSHES ACROSS THE GREAT
LAKES. SINCE LOW LEVEL MOISTURE IS LIMITED, NOT MUCH IN THE WAY OF
AN ACCUMULATION IN SNOW IS EXPECTED AND SHOWERS SHOULD END AROUND
12Z. ONLY OTHER CHANGES TO FORECAST WERE TO QUICKEN THE DOWNWARD
TREND IN TEMPERATURES THROUGH THE OVERNIGHT AS RECENT RUNS OF THE
HRRR, RUC, AND NAM SEEM TO BEST DEPICT CURRENT TEMPERATURES.
LOOKING AT THE CURRENT OBSERVATIONS UPSTREAM AND BUFKIT
PROFILES, WINDS WILL REMAIN GUSTY OVERNIGHT AND GRADUALLY BACK OFF
ON FRIDAY. TEMPERATURES WILL GENERALLY REMAIN CLOSE TO NORMAL
LEVEL FRIDAY AS HIGH PRESSURE BUILDS OVER THE REGION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A FAST MOVING SHORTWAVE AND LOW PRESSURE CENTER MOVING ALONG MID
ATLANTIC FRIDAY NIGHT INTO EARLY SATURDAY WILL SPREAD CLOUDS INTO
THE SOUTHEAST RIDGES BUT APPEARS PRECIP WILL REMAIN SOUTH.
AS FOR THE REST OF THE AREA, HIGH PRESSURE WILL ALLOW FOR DRY
WEATHER FRIDAY NIGHT BEFORE A SHORT WAVE TROUGH WILL BEGIN TO DIVE
FROM THE GREAT LAKES SOUTHEASTWARD INTO THE AREA. THIS WILL RETURN
THE CHANCE OF SNOW SHOWERS, ESPECIALLY NORTH OF PITTSBURGH
SATURDAY MORNING, SPREADING SOUTH ACROSS THE REGION BY THE
EVENING. 850MB TEMPERATURES PROGGED TO FALL TO -10 C DURING DAY
AND THIS WILL COMBINE WITH SHORTWAVE TO BRING LIGHT ACCUMULATIONS
TO THE RIDGES AND I-80 CORRIDOR SATURDAY NIGHT TO EARLY SUNDAY.
TEMPERATURES WILL BE NEAR NORMAL TO A BIT BELOW.
ON SUNDAY LOWER AND MID LEVEL FLOW WILL BEGIN TO TURN WESTERLY
AND SNOW SHOWERS WILL DIMINISH WITH TEMPERATURES AGAIN AROUND
NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE MODELS SHOW CLOSED UPPER LOW OVER THE SOUTHERN PLAINS
MONDAY...GRADUALLY WEAKENING AS IT TRACKS NORTHEAST THROUGH MIDWEEK.
ASSOCIATED SURFACE LOW IS FORECAST TO TRACK FROM THE SOUTHERN PLAINS
INTO THE MID MS VALLEY BY WEDNESDAY...AND OFF THE MID ATLANTIC COAST
THURSDAY.
WENT CLOSE TO HPC GUIDANCE KEEPING THE FORECAST AREA DRY (POPS LESS
THAN 25 PERCENT) THROUGH LATE MONDAY...THEN CHANCE POPS TUESDAY AND
WEDNESDAY. LIMITED SCATTERED SHOWERS TO EASTERN SECTIONS THURSDAY AS
SYSTEM EXITS.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
PER RECENT SURFACE AND SATELLITE DATA PLUS HRRR AND NAM MODEL
OUTPUT, EXPECT BRISK WESTERLY LOWLEVEL WINDS TO PRODUCE SCATTERED TO
BROKEN STRATOCUMULUS AT MAINLY VFR LEVELS. NAM MODEL PROFILES SHOW
SURFACE WINDS CAN GUST TO 30 KTS AT TIMES UNTIL 08Z-12Z, THEN
SLACKEN TO MAINLY 10-15 KTS DAYTIME FRIDAY.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
SURFACE RIDGE SHOULD PROVIDE GENERALLY VFR CONDITIONS FRIDAY NIGHT
INTO EARLY SATURDAY. A SHORT WAVE TROUGH AND ASSOCIATED WEAK SURFACE
FRONT, MOVING ACROSS THE GREAT LAKES, WILL BRING SCATTERED SNOW
SHOWERS AND THE POTENTIAL FOR RESTRICTIONS SATURDAY AFTERNOON INTO
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
729 PM EST THU DEC 15 2011
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS EVENING WITH SHOWERS AND
GUSTY WINDS. COLDER AIR BEHIND THE FRONT WILL BRING A FEW SNOW SHOWERS
TO THE RIDGES AND NORTHWEST PENNSYLVANIA LATER TONIGHT. DRY AND
SEASONABLE FRIDAY FOLLOWED BY SCATTERED SNOW SHOWERS SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
FOR THE EVENING UPDATE, ADJUSTED POPS AS THE BULK OF THE
PRECIPITATION IS QUICKLY PROGRESSING TOWARDS THE EASTERN PORTION
OF THE CWA. ONLY OTHER ADJUSTMENTS WERE MADE TO THE OVERNIGHT
TEMPS, DEWPOINTS, AND WINDS TO BETTER MATCH CURRENT OBSERVATIONS
AND RECENT MODEL TRENDS. THE MOST RECENT RUC AND HRR SEEM TO
HANDLE THE TEMPERATURE DROP BEHIND THE FRONT THE BEST SO WENT VERY
CLOSE TO THOSE NUMBERS, TWEAKED WITH NAM GUIDANCE. BUFKIT SOUNDINGS ARE
KEEPING THE WINDS GUSTY THROUGH THE OVERNIGHT HOURS BEFORE BACKING
OFF FRIDAY.
COLD FRONT CHUGGING ALONG INTO CENTRAL OHIO BY 20Z WITH A BAND OF
SHOWERS ALONG FRONT AND SCATTERED SHOWERS AHEAD OF IT. AFTER FRONT
PASSES TEMPERATURES WILL GRADUALLY FALL OVERNIGHT WITH NORTHWEST
FLOW ACROSS LAKES BRINGING A BRIEF PERIOD OF SNOW SHOWERS LATER
TONIGHT INTO EARLY FRIDAY. WHILE 850MB TEMPERATURES WILL BE NEAR
-8 C BY DAYBREAK INVERSION HEIGHTS WILL BE LOW AND LOWERING WITH A
LACK OF DEEP MOISTURE. SO LITTLE IF ANY ACCUMULATION.
AS DAY GOES ON FRIDAY, HIGH PRESSURE WILL WORK INTO REGION WITH
NEAR NORMAL TEMPS AND A MIX OF CLOUDS AND SUNSHINE. TIGHT SFC
PRESS GRADIENT WILL KEEP WINDS GUSTY FIRST HAVE OF TONIGHT WITH
FROPA THEN DIMINISHING AFTER MIDNIGHT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A FAST MOVING SHORTWAVE AND LOW PRESSURE CENTER MOVING ALONG MID
ATLANTIC FRIDAY NIGHT INTO EARLY SATURDAY WILL SPREAD CLOUDS INTO
THE SOUTHEAST RIDGES BUT APPEARS PRECIP WILL REMAIN SOUTH.
AS FOR THE REST OF THE AREA, HIGH PRESSURE WILL ALLOW FOR DRY
WEATHER FRIDAY NIGHT BEFORE A SHORT WAVE TROUGH WILL BEGIN TO DIVE
FROM THE GREAT LAKES SOUTHEASTWARD INTO THE AREA. THIS WILL RETURN
THE CHANCE OF SNOW SHOWERS, ESPECIALLY NORTH OF PITTSBURGH
SATURDAY MORNING, SPREADING SOUTH ACROSS THE REGION BY THE
EVENING. 850MB TEMPERATURES PROGGED TO FALL TO -10 C DURING DAY
AND THIS WILL COMBINE WITH SHORTWAVE TO BRING LIGHT ACCUMULATIONS
TO THE RIDGES AND I-80 CORRIDOR SATURDAY NIGHT TO EARLY SUNDAY.
TEMPERATURES WILL BE NEAR NORMAL TO A BIT BELOW.
ON SUNDAY LOWER AND MID LEVEL FLOW WILL BEGIN TO TURN WESTERLY
AND SNOW SHOWERS WILL DIMINISH WITH TEMPERATURES AGAIN AROUND
NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE MODELS SHOW CLOSED UPPER LOW OVER THE SOUTHERN PLAINS
MONDAY...GRADUALLY WEAKENING AS IT TRACKS NORTHEAST THROUGH MIDWEEK.
ASSOCIATED SURFACE LOW IS FORECAST TO TRACK FROM THE SOUTHERN PLAINS
INTO THE MID MS VALLEY BY WEDNESDAY...AND OFF THE MID ATLANTIC COAST
THURSDAY.
WENT CLOSE TO HPC GUIDANCE KEEPING THE FORECAST AREA DRY (POPS LESS
THAN 25 PERCENT) THROUGH LATE MONDAY...THEN CHANCE POPS TUESDAY AND
WEDNESDAY. LIMITED SCATTERED SHOWERS TO EASTERN SECTIONS THURSDAY AS
SYSTEM EXITS.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
PER RECENT SURFACE AND RADAR DATA PLUS HRRR AND NAM MODEL OUTPUT,
EXPECT COLD FRONTAL BAND OF SHOWERS TO PRODUCE BRIEF IFR CONDITIONS
AND WIND GUSTS TO ABOUT 30 KTS.
FRONTAL SHOWERS WILL MOVE PAST KMGW AND KLBE BY 00Z. POST FRONTAL
DRYING WILL PROMOTE MAINLY MVFR STRATOCUMULUS OVERNIGHT INTO MIDDAY
FRIDAY. NAM MODEL PROFILES SUGGEST WESTERLY WINDS CAN STILL GUST TO
30 KTS AT TIMES UNTIL 08Z-12Z.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
SURFACE RIDGE SHOULD PROVIDE GENERALLY VFR CONDITIONS FRIDAY NIGHT
INTO EARLY SATURDAY. A SHORT WAVE TROUGH AND ASSOCIATED WEAK SURFACE
FRONT MOVING ACROSS THE GREAT LAKES WILL BRING SCATTERED SNOW
SHOWERS AND THE POTENTIAL FOR RESTRICTIONS SATURDAY AFTERNOON INTO
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
506 PM EST WED DEC 14 2011
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH OF THE AREA THIS EVENING, WITH A BREAK
IN PRECIPITATION EXPECTED EARLY TONIGHT. SHOWERS WILL BE MORE
PERSISTENT THURSDAY WHEN A COLD FRONT CROSSES THE REGION. IN THE
WAKE OF THE FRONT, SNOW SHOWERS WILL BE POSSIBLE EARLY FRIDAY
ALONG THE I-80 CORRIDOR AND EASTERN RIDGES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES WEAK RIDGING MOVING
ACROSS THE UPPER OHIO VALLEY. AT THE SURFACE, A 1006MB LOW IS
CENTERED ACROSS THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING
ACROSS THE MISSOURI AND LOWER OHIO VALLEYS. WELL UPSTREAM, A COLD
FRONT EXTENDS SOUTH OF THE LOW INTO THE SOUTHERN PLAINS. AHEAD OF THE
WARM FRONT, LIFT FROM OVERRUNNING IS ALLOWING FOR SCATTERED
SHOWERS TO PUSH NORTHEAST OF THE AREA. A LAYER OF 850-500MB DRY
AIR IN THE WARM SECTOR IS ALLOWING FOR CLEARING ACROSS PORTIONS OF
EASTERN OHIO.
TONIGHT...THE WARM FRONT WILL LIFT NORTH OF THE AREA. WITH LIFT
FROM OVERRUNNING PUSHING NORTH OF THE AREA, EXPECT MOST OF THE
FORECAST AREA TO BE DRY FROM 00Z THROUGH 06Z. AFTER 06Z, NAM12 AND
WRF-NMM SUPPORT DEEPER MOISTURE ASSOCIATED AHEAD OF THE COLD FRONT
IN ILLINOIS BEGINNING TO PUSH INTO EASTERN OHIO. THUS, THIS WILL
ALLOW FOR AN AREA OF MORE PERSISTENT SHOWERS TO BEGIN TO SHIFT
INTO THE AREA. CHC POPS IN OHIO WILL INCREASE TO CATEGORICAL POPS
ACROSS WESTERN PA AND EASTERN OHIO BY DAWN ON THURSDAY.
STRONG WARM AIR ADVECTION OVERNIGHT WILL ALLOW FOR NEAR STEADY TEMPS
INITIALLY THAT WILL BEGIN TO INCREASE DURING THE PRE-DAWN HOURS.
TEMPS OVERNIGHT WILL RANGE FROM THE MID 40S ACROSS THE EASTERN
RIDGES TO THE LOWER 50S IN EASTERN OHIO.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
GFS/NAM/CANADIAN ARE IN REASONABLE AGREEMENT IN THE TIMING AND QPF
WITH THE COLD FRONT AS IT PUSHES ACROSS THE OHIO VALLEY AND INTO THE
AREA BY THURSDAY EVENING. CATEGORICAL POPS ARE FORECAST AHEAD OF THE
FRONT WITH AROUND A HALF OF AN INCH OF RAIN EXPECTED ON THURSDAY.
WARM AIR ADVECTION WILL BE ONGOING IN A SOUTHWESTERLY LOW-LEVEL FLOW
IN THE WARM SECTOR. FORCING ALONG AND AHEAD OF THE FRONT ALONG WITH
WEAK INSTABILITY AND STRONG SHEAR MAY BE JUST ENOUGH FOR A FEW
THUNDERSTORMS EARLY THURSDAY AFTERNOON IN EASTERN OHIO. THUS, HAVE
INCLUDED A SCHC FOR THUNDER THERE. IN ADDITION, A TIGHTENING
PRESSURE GRADIENT AHEAD OF THE FRONTAL TROUGH WILL ALLOW FOR WIND
GUSTS OF UP TO 25 TO 30 MPH THURSDAY AFTERNOON.
MAV/MET GUIDANCE SEEM TO BE RESOLVING WARM AIR ADVECTION FAIRLY WELL
AHEAD OF THE FRONT, SO FORECAST IS A MOS BLEND. THIS WILL ALLOW HIGHS
ON THURSDAY TO BE 15-20 DEGREES ABOVE NORMAL. LOCATIONS IN
NORTH-CENTRAL WV AND PORTIONS OF EASTERN OHIO HAVE A GOOD SHOT OF
HITTING 60 TOMORROW.
THURSDAY NIGHT...THE COLD FRONT IS PROGGED TO PUSH EAST OF
PITTSBURGH AFTER 00Z FRIDAY WITH PRECIPITATION QUICKLY CUTTING OFF
IN THE WAKE OF THE FRONT. WINDS WILL SHIFT TO NORTHWESTERLY BEHIND
THE FRONT WITH COLD AIR ADVECTION ENSUING ACROSS LAKE ERIE. THE
TEMP DIFFERENTIAL BETWEEN 850 TEMPS AND LAKE ERIE SHOULD BE ENOUGH
TO INSTIGATE SOME LAKE EFFECT SNOW SHOWERS FOR THE I-80 CORRIDOR
BY THE PRE-DAWN HOURS FRIDAY AND UPSLOPING SNOW SHOWERS BY DAWN
FOR THE EASTERN RIDGES. COLD AIR ADVECTION WILL ALLOW FOR LOW
TEMPS TO DROP OFF SHARPLY OVERNIGHT WITH LOWS IN THE LOWER 30S
ACROSS MUCH OF THE AREA.
FRIDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST WITH A
COOL NORTHWESTERLY FLOW OFF THE GREAT LAKES CONTINUING. SNOW
SHOWERS FOR THE I-80 CORRIDOR AND EASTERN RIDGES WILL DIMINISH BY
THE AFTERNOON AS 850 TEMPS WARM AND WIND COMPONENT BECOMES MORE
WESTERLY. ACCUMULATIONS WILL BE LIGHT, GENERALLY LESS THAN AN INCH
WITH THE SNOW SHOWERS BEHIND THE FRONT. THE NORTHWESTERLY FLOW WILL
ALSO SERVE TO KEEP THE AREA CLOUDY ON FRIDAY. WITH THE ARCTIC AIR
MASS WORKING INTO THE AREA, TEMPERATURES WILL BE SLOW TO RECOVER
THROUGHOUT THE DAY. HIGHS WILL RANGE FROM THE MID 30S ACROSS THE
EASTERN RIDGES AND I-80 CORRIDOR TO THE LOWER 40S NORTH-CENTRAL WV.
FRIDAY NIGHT AND SATURDAY...HIGH PRESSURE WILL ALLOW FOR MOSTLY
DRY WEATHER FRIDAY NIGHT AND MOST OF THE DAY SATURDAY. LATE IN THE
DAY, A SHORT WAVE TROUGH WILL BEGIN TO DIVE FROM THE GREAT LAKES
SOUTHEASTWARD INTO THE AREA. THIS WILL RETURN THE CHANCE OF SNOW
SHOWERS, ESPECIALLY NORTH OF PITTSBURGH, BY THE EVENING.
TEMPERATURES WILL BE NEAR NORMAL SEASONAL VALUES.
&&
.LONG TERM /SATURDAY NIGHT NIGHT THROUGH WEDNESDAY/...
STILL VARYING MODEL SOLUTIONS THIS PERIOD REGARDING HOW MUCH ENERGY
THE NORTHERN BRANCH OF THE UPPER LEVEL JET, COMING EAST FROM
SOUTHERN CANADA, INPUTS INTO THE SOUTHERN JET STREAM BRANCH
EMANATING FROM CALIFORNIA. DEFERRING TO HPC OPINION, FAVORED NAEFS
SOLUTION OVER ECENS MODEL OUTPUT, WHICH SHOWED THE NORTHERN BRANCH
HAVING GREATER INFLUENCE.
THE EFFECT THIS HAS ON THE UPPER OHIO VALLEY WILL BE INITIALLY A
COLDER AIRFLOW ACROSS THE GREAT LAKES, WHICH WILL SUBSEQUENTLY
PROVIDE A LARGER COVERAGE OF LAKE ENHANCED CLOUDS AND LIGHT SNOW
SHOWERS SUNDAY.
IT ALSO MEANS A SLOWER-MOVING AND MORE DEVELOPED LOW PRESSURE SYSTEM
COMING NORTHEAST FROM TEXAS EARLY NEXT WEEK. PER GFS MOS AND NAEFS
MEDIAN VALUES, DAYTIME TEMPERATURES WILL BE NEAR SEASONABLE VALUES.
ASSOCIATED CLOUDS CAN CAUSE NIGHTTIME TEMPERATURES TO BE WARMER
THAN NORMAL, BUT NO WARMER THAN FREEZING FOR MOST LOCATIONS. SO
HAVE FORECASTED MIXED PRECIPITATION LATE MONDAY INTO WEDNESDAY.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
PER RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED WITH RECENT
HRRR, GFS LAMP AND NAM MODEL OUTPUT, EXPECT POST-WARM FRONTAL BAND
OF IFR STRATUS TO BEGIN TO DISSIPATE THIS EVENING.
THIS SCENARIO IS TYPICALLY NOT FAVORED FROM A DIURNAL CLIMATOLOGICAL
VIEWPOINT. HOWEVER THERE APPEARS TO INCREASING LOW LEVEL DRYING IN
THE WARM SECTOR THAT CONDITIONS IMPROVE TO AT LEAST MVFR.
NAM MODEL PROFILES CONTINUE TO SHOW A LOW LEVEL JET, WITH
SOUTHWEST WINDS NEAR 40KT AT 2KFT AGL, DEVELOPING AFTER 03Z. HENCE
HAVE ADDED LOW LEVEL WIND SHEAR /LLWS/ TO ALL SITES 03Z-10Z.
NAM MODEL PROFILES THEN SHOW PASSAGE OF A COLD FRONTAL BAND OF
MODERATE SHOWERS LATE TONIGHT INTO MIDDAY THURSDAY, THAT SHOULD
LOWER FLIGHT CONDITIONS BACK INTO THE IFR RANGE. THE COLD FRONTAL
SHOWER BAND WILL PROVIDE SUFFICIENT VERTICAL MIXING TO COUPLE SOME
FASTER WINDS TO THE SURFACE AND SO END THE LLWS THREAT. NEAR THE
RIDGES, SURFACE SOUTHERLY WINDS CAN GUST TO 20-25 KTS. POST COLD
FRONTAL VERTICAL MIXING CAN INDUCE SOUTHWEST WIND GUSTS TO 25-30 KTS
FOR ALL SITES THROUGH THURSDAY AFTERNOON. AS SHOWER INTENSITY
DECREASES, THE VERTICAL MIXING SHOULD IMPROVE FLIGHT CONDITIONS TO
MVFR AS THE DAY WEARS ON.
OUTLOOK... THURSDAY NIGHT THROUGH MONDAY...
FOR THURSDAY NIGHT, FORESEE POSSIBLE LINGERING COLD POOL MVFR
STRATOCUMULUS AREAWIDE. FOR FRIDAY INTO SUNDAY, LINGERING MVFR
STRATOCUMULUS WILL BE POSSIBLE MAINLY NORTH AND MOUNTAINS. FOR
MONDAY, INCOMING WARM FRONTAL SHOWERS MAY PRODUCE RESTRICTIONS LATE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
118 PM EST WED DEC 14 2011
.SYNOPSIS...
A WARM FRONT WILL LIFT THROUGH THE UPPER OHIO VALLEY THIS
AFTERNOON, BRINGING SHOWERS TO THE AREA. SHOWERS WILL BE MORE
PERSISTENT THURSDAY WHEN A COLD FRONT CROSSES THE REGION. IN THE
WAKE OF THE FRONT, SNOW SHOWERS WILL BE POSSIBLE EARLY FRIDAY
ALONG THE I-80 CORRIDOR AND EASTERN RIDGES.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST RADAR TRENDS AS OVERRUNNING PRECIP HAS DECREASED
SIGNIFICANTLY IN COVERAGE.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES WEAK RIDGING MOVING
ACROSS THE UPPER OHIO VALLEY. AT THE SURFACE, A 1006MB LOW IS
CENTERED ACROSS THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING
ACROSS THE MISSOURI AND LOWER OHIO VALLEYS. WELL UPSTREAM, A COLD
FRONT EXTENDS SOUTH OF THE FEATURE ACROSS THE SOUTHERN PLAINS. AHEAD
OF THE WARM FRONT, LIFT FROM OVERRUNNING IS ALLOWING FOR SCATTERED
SHOWERS TO PUSH ACROSS THE AREA. A LAYER OF 850-500MB DRY AIR IN THE
WARM SECTOR IS ALLOWING FOR CLEARING ACROSS SOUTHERN WEST VIRGINIA.
THIS AFTERNOON...THE WARM FRONT WILL CONTINUE TO PUSH NORTHWARD
CLOSER TO THE AREA WITH THE BEST LIFT WILL SHIFTING NORTH OF THE
AREA. THUS, SHOWERS WILL DECREASE IN COVERAGE ACROSS THE AREA AND
COME TO AN END SOUTH OF PITTSBURGH. SOME CLOUD BREAKS ARE EXPECTED
SOUTH OF PITTSBURGH AS THE LAYER OF DRY AIR MOVES INTO THE AREA ALONG
WITH THE WARM SECTOR. HIGHS WILL BE AROUND 10 DEGREES ABOVE
NORMAL, RANGING FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND
EASTERN RIDGES TO THE LOWER 50S IN NORTH-CENTRAL WV AND EASTERN
OHIO.
TONIGHT...THE WARM FRONT WILL LIFT NORTH OF THE AREA. WITH LIFT
FROM OVERRUNNING PUSHING NORTH OF THE AREA, EXPECT MOST OF THE
FORECAST AREA TO BE DRY FROM 00Z THROUGH 06Z. AFTER 06Z, NAM12 AND
WRF-NMM SUPPORT DEEPER MOISTURE ASSOCIATED AHEAD OF THE COLD FRONT
IN ILLINOIS BEGINNING TO PUSH INTO EASTERN OHIO. THUS, THIS WILL
ALLOW FOR AN AREA OF MORE PERSISTENT SHOWERS TO BEGIN TO SHIFT
INTO THE AREA. CHC POPS IN OHIO WILL INCREASE TO CATEGORICAL POPS
ACROSS WESTERN PA AND EASTERN OHIO BY DAWN ON THURSDAY.
STRONG WARM AIR ADVECTION OVERNIGHT WILL ALLOW FOR NEAR STEADY TEMPS
INITIALLY AND BEGINNING TO INCREASE DURING THE PRE-DAWN HOURS. THUS,
TEMPS OVERNIGHT WILL RANGE FROM THE MID 40S ACROSS THE EASTERN
RIDGES TO THE LOWER 50S IN EASTERN OHIO.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
THE MODELS ARE IN REASONABLE AGREEMENT THAT AN AREA OF DRY AIR WILL
PUSH INTO THE AREA WITH WAA IN THE WARM SECTOR AS A COLD FRONT
APPROACHES FROM THE WEST TONIGHT. WITH A BREAK IN PRECIP EXPECTED,
DRY OR SCHC POPS ARE FORECAST ACROSS MOST OF THE AREA. FORCING
FROM A COLD FRONT WILL SUPPORT PRECIP FOR THE AREA WITH
CATEGORICAL POPS REACHING THE PITTSBURGH METRO BY DAWN ON
THURSDAY. MORE PERSISTENT RAINFALL IS EXPECTED THROUGH MUCH OF THE
DAY THURSDAY AS THE FRONT SLOWLY PROGRESSES ACROSS THE OHIO
VALLEY. ONGOING WARM AIR ADVECTION WILL ALLOW FOR TEMPS TO BE 15
TO 20 DEGREES ABOVE NORMAL.
THE FRONT WILL CROSS THE AREA THURSDAY NIGHT WITH A LOW-LEVEL
NORTHWESTERLY FLOW AND HIGH PRESSURE BUILDING IN FROM THE WEST IN
ITS WAKE. 850MB AND LAKE ERIE TEMP DIFFERENTIAL WILL BE SUFFICIENT
TO SUPPORT A FEW LAKE EFFECT SNOW SHOWERS IN THE WAKE OF THIS
SYSTEM ON FRIDAY. TEMPS ON FRIDAY WILL BE SLIGHTLY BELOW NORMAL
UNDER CAA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
EXPECT A MAINLY DRY WEEKEND WITH NEAR TO BELOW NORMAL TEMPS.
STILL A GOOD DEAL OF UNCERTAINTY FOR EARLY NEXT WEEK. DIFFERENCES
IN MEDIUM RANGE MODELS WILL PROMOTE VERY LITTLE CHANGES TO LONG
TERM FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED WITH RECENT
HRRR, GFS LAMP AND NAM MODEL OUTPUT, EXPECT POST-WARM FRONTAL BAND
OF IFR STRATUS AND DRIZZLE TO SPREAD NORTHEASTWARD THROUGH MUCH OF
THE UPPER OHIO VALLEY THIS AFTERNOON. HRRR FLIGHT RULE FORECASTS AND
NAM MODEL PROFILES, IN PARTICULAR, SHOW THE IFR CONDITIONS CAN
LINGER INTO EVENING. ITS POSSIBLE WITH LOWLEVEL SOUTHEAST WINDS THAT
LOCATIONS, SUCH AS KLBE, MAY DETERIORATE TO MAINLY JUST MVFR
CONDITIONS DUE TO DOWNSLOPING EFFECTS.
ALTHOUGH NOT FAVORED FROM A DIURNAL CLIMATOLOGICAL VIEWPOINT, THERE
MAY BE SUFFICIENT LOW LEVEL DRYING IN THE WARM SECTOR THAT
CONDITIONS IMPROVE TO MVFR. NAM MODEL PROFILES CONTINUE TO SHOW A
LOW LEVEL JET, WITH SOUTHWEST WINDS NEAR 40KT AT 2KFT AGL,
DEVELOPING AFTER 03Z. HENCE HAVE ADDED LOW LEVEL WIND SHEAR /LLWS/
TO ALL SITES 03Z-10Z.
NAM MODEL PROFILES THEN SHOW PASSAGE OF A COLD FRONTAL BAND OF
MODERATE SHOWERS THAT SHOULD LOWER FLIGHT CONDITIONS INTO THE IFR
RANGE. THE COLD FRONTAL SHOWER BAND WILL PROVIDE SUFFICIENT VERTICAL
MIXING TO COUPLE SOME FASTER WINDS TO THE SURFACE AND SO END THE
LLWS THREAT. NEAR THE RIDGES, SURFACE SOUTHERLY WINDS CAN GUST TO
20-25 KTS. POST COLD FRONTAL VERTICAL MIXING CAN INDUCE SOUTHWEST
WIND GUSTS TO 25-30 KTS FOR ALL SITES THROUGH THURSDAY AFTERNOON.
AS SHOWERS INTENSITY DECREASES, THIS VERTICAL MIXING SHOULD THEN
IMPROVE FLIGHT CONDITIONS TO MVFR.
OUTLOOK... THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT AND FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL MVFR
STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, LINGERING MVFR
STRATOCUMULUS POSSIBLE MAINLY NORTH AND MOUNTAINS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1100 PM EST THU DEC 15 2011
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(340 PM EST THU DEC 15 2011)
A COLDER AIRMASS CONTINUES TO FILTER INTO SOUTHWEST LOWER MICHIGAN
IN THE WAKE OF A THURSDAY MORNING COLD FRONTAL PASSAGE. WEST TO
NORTHWEST WINDS WILL DROP LOWS INTO THE 20S IN MOST LOCATIONS
TONIGHT. IT WILL BE WINDY THIS EVENING BEFORE WINDS SUBSIDE
CONSIDERABLY OVERNIGHT. LAKE EFFECT SNOW SHOWERS ARE EXPECTED THIS
EVENING AND AGAIN FRIDAY NIGHT INTO SATURDAY. ACCUMULATIONS WILL BE
LIGHT TONIGHT ON THE ORDER OF A DUSTING TO POSSIBLY A HALF INCH IN A
FEW SPOTS. LOCALIZED ACCUMULATIONS FRIDAY NIGHT INTO SATURDAY MAY
REACH AN INCH OR TWO...BUT MOST LOCATIONS WILL SEE VERY LITTLE
ACCUMULATION. EVEN WITH THE COOL DOWN...TEMPERATURES WILL REMAIN
SLIGHTLY ABOVE NORMAL INTO THE WEEKEND.
&&
.SHORT TERM...(1100 PM EST THU DEC 15 2011)
(TONIGHT THROUGH SATURDAY NIGHT)
WE ARE ALLOWING THE WIND ADVISORY HEADLINE FOR OUR LAKESHORE COUNTIES
TO EXPIRE AT 11 PM. AT 04Z SFC OBS INDICATE WIND SPEEDS ARE STARTING
TO DECREASE SOMEWHAT AND THE DIMINISHING TREND OF WINDS WILL
CONTINUE OVERNIGHT.
REMAINDER OF PREVIOUS SHORT TERM FCST DISCUSSION FOLLOWS...AS FOR
LAKE EFFECT SNOW CHANCES...THERE ARE TWO TIME FRAMES OF
POTENTIAL. THE FIRST BEING THIS EVENING...WHERE DEEPER MOISTURE
INTERACTS WITH INCREASING INSTABILITY. THE DEEPER MOISTURE IS ONLY
IN PLACE THROUGH THE 03Z TO 06Z TIME FRAME THOUGH AFTER WHICH TIME
IT DWINDLES TO 4000-5000FT OR LESS. THIS EVENING...EXPECT SNOW
SHOWER ACTIVITY WITH LIGHT ACCUMULATIONS (INCH OR LESS) ACROSS
CENTRAL LOWER MICHIGAN AND POSSIBLY ALONG THE HIGHWAY 131 CORRIDOR
(GIVEN THE STIFF WESTERLY WINDS DISPLACING BANDS INLAND A BIT). A
WET WARM GROUND WILL COUNTERACT THE SNOW SHOWERS SOME.
RELATIVE HUMIDITY IS QUITE LACKING IN THE OVERNIGHT THROUGH FRIDAY
EVENING TIME FRAME AND THEREFORE NOT EXPECTING MUCH IN THE WAY OF
SNOW SHOWERS DESPITE DELTA T/S IN THE MIDDLE TEENS C.
A COUPLE OF SHORTWAVE TROUGHS ROTATE THROUGH THE REGION FRIDAY NIGHT
INTO SATURDAY WHICH SHOULD GIVE A BOOST TO LAKE EFFECT CLOUDS AND
SNOW SHOWERS. SOME MINOR ACCUMULATIONS ARE POSSIBLE ALONG AND WEST
OF HIGHWAY 131. ENVISION DUSTING TO HALF INCH ACCUMS IN MOST
AREAS...BUT SOME LOCALIZED ACCUMS OF AN INCH OR TWO WILL BE
POSSIBLE.
&&
.LONG TERM...(340 PM EST THU DEC 15 2011)
(SUNDAY THROUGH THURSDAY)
SUNDAY LOOKS DRY AS A SFC HIGH AND NW FLOW ALOFT PRODUCES SOME
SUNSHINE ACROSS THE GREAT LAKES.
MODELS CONTINUE TO BE ON DIFFERENT PAGES WRT THE SRN STREAM LOW
MONDAY AND TUESDAY. BOTH THE ECMWF/GFS SHOW A SRN STREAM SHORT WAVE
BEING KICKED NEWD BY A NRN STREAM WAVE. THE ECMWF HOWEVER TAKES THE
LOW MORE EWD THROUGH THE OHIO VALLEY VS THE GFS THAT TAKES THE LOW
OVER LWR MI. BASED ON THE UPPER WAVE TRACK I TEND TO BUY THE GFS
TRACK MORE. THIS TRACK WOULD ALSO BRING WARMER AIR INTO THE CWA.
THUS WE/LL KEEP THE RAIN/SNOW MIX MON-TUE NIGHT. LIGHT SNOW POSSIBLE
ON THE BACK SIDE OF THE SYSTEM WEDNESDAY AS H8 TEMPS FALL TO -5C IN
NW FLOW. TEMPS WILL CONTINUE TO BE A FEW DEGREES WARMER THAN NORMAL
THROUGH THE PERIOD.
&&
.AVIATION...(640 PM EST THU DEC 15 2011)
WINDS WILL BE AN ISSUE THIS EVENING WITH MANY SITES GUSTING OVER 25
KNOTS. THESE STRONG WIND GUSTS COMBINED WITH COLD AIR ADVECTION
WILL LEAD TO TURBULENT MIXING. THE WINDS WILL SETTLE DOWN MAINLY
AFTER 03Z. MVFR CONDITIONS WILL PREVAIL THROUGH THE EVENING...BUT
IMPROVEMENT TO VFR IS EXPECTED AS DRIER AIR MOVES IN FROM THE WEST
BY NOON FRIDAY. A FEW RAIN SHOWERS ARE EXPECTED THIS EVENING...AND
SOME OF IT WILL BE SNOW UP TOWARD KRQB AND KHTL.
&&
.MARINE...(340 PM EST THU DEC 15 2011)
WILL MAINTAIN THE GALE WARNING THROUGH THIS EVENING AS THE CORE OF
THE WIND LOOKS TO COME THROUGH BETWEEN 400PM AND 1000PM. WE WILL
EXTEND THE GALE SLIGHTLY TO GIVE A LITTLE BIT OF A BUFFER ON THE
BACK END...THROUGH 100 AM. RUC OVERVIEW/S ALONG THE
COAST ARE SHOWING 40 KNOTS OF WIND DOWN TO AROUND 1000FT...WHICH
SHOULD TRANSLATE INTO FREQUENT GALE FORCE GUSTS AT THE COASTAL
SITES. WINDS WILL DROP BELOW GALE FORCE AFTER MIDNIGHT AND WE WILL
NEED A SMALL CRAFT ADVISORY THAT WILL STRETCH INTO THE DAYLIGHT
HOURS OF FRIDAY. SUB SMALL CRAFT ADVISORIES CONDITIONS ARE EXPECTED
FROM FRIDAY EVENING INTO SUNDAY.
&&
.HYDROLOGY...(340 PM EST THU DEC 15 2011)
ONE RIVER FLOOD WARNING (VICKSBURG) AND THREE RIVER FLOOD ADVISORIES
(IONIA...BURLINGTON AND HOLT) ARE CURRENTLY IN EFFECT. WE ARE NOT
EXPECTING MUCH IN THE WAY OF CHANGES TO RIVER HEADLINES AT THIS
POINT GIVEN THE RAINFALL HAS OCCURRED AND IS MAKING IT/S WAY INTO
THE RIVERS. RAINFALL TOTALS RANGED FROM A HALF INCH TO SLIGHTLY OVER
ONE INCH FOR THE LAST 24 HOURS OR SO. COLDER AIR IS NOW SURGING INTO
THE AREA AND THIS WILL ACT TO SLIGHTLY SUPPRESS RUN OFF SLIGHTLY.
SO...BOTTOM LINE RISES WILL CONTINUE THE NEXT COUPLE OF DAYS WITH
MOST SITES IN THE AREA REMAINING UNDER BANKFULL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING ENTIRE NEARSHORE AREA THROUGH 100 AM.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE/LAURENS
LONG TERM: 93
AVIATION: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
640 PM EST THU DEC 15 2011
LATEST UPDATE...AVIATION...
.SYNOPSIS...(340 PM EST THU DEC 15 2011)
A COLDER AIRMASS CONTINUES TO FILTER INTO SOUTHWEST LOWER MICHIGAN
IN THE WAKE OF A THURSDAY MORNING COLD FRONTAL PASSAGE. WEST TO
NORTHWEST WINDS WILL DROP LOWS INTO THE 20S IN MOST LOCATIONS
TONIGHT. IT WILL BE WINDY THIS EVENING BEFORE WINDS SUBSIDE
CONSIDERABLY OVERNIGHT. LAKE EFFECT SNOW SHOWERS ARE EXPECTED THIS
EVENING AND AGAIN FRIDAY NIGHT INTO SATURDAY. ACCUMULATIONS WILL BE
LIGHT TONIGHT ON THE ORDER OF A DUSTING TO POSSIBLY A HALF INCH IN A
FEW SPOTS. LOCALIZED ACCUMULATIONS FRIDAY NIGHT INTO SATURDAY MAY
REACH AN INCH OR TWO...BUT MOST LOCATIONS WILL SEE VERY LITTLE
ACCUMULATION. EVEN WITH THE COOL DOWN...TEMPERATURES WILL REMAIN
SLIGHTLY ABOVE NORMAL INTO THE WEEKEND.
&&
.SHORT TERM...(340 PM EST THU DEC 15 2011)
(TONIGHT THROUGH SATURDAY NIGHT)
MAIN FOCUS OF THE SHORT TERM REVOLVES AROUND THE WIND THIS EVENING
AND THEN CHANCES FOR LAKE EFFECT SNOW THROUGH THE PERIOD.
MAINTAINED THE WIND ADVISORY WITH THE CORE OF THE WIND STILL SET TO
COME THROUGH. MAIN CONCERN ARE A FEW GUSTS INTO THE 45 TO 50 MPH
RANGE BETWEEN 400 PM AND 1000 PM OR SO. LOCATIONS NEAR LAKE MICHIGAN
STAND THE BEST CHANCE OF SEEING GUSTS TO THIS SPEED. THE WIND SHOULD
GRADUALLY SUBSIDE FROM MIDNIGHT INTO FRIDAY MORNING.
AS FOR LAKE EFFECT SNOW CHANCES...THERE ARE TWO TIME FRAMES OF
POTENTIAL. THE FIRST BEING THIS EVENING...WHERE DEEPER MOISTURE
INTERACTS WITH INCREASING INSTABILITY. THE DEEPER MOISTURE IS ONLY
IN PLACE THROUGH THE 03Z TO 06Z TIME FRAME THOUGH AFTER WHICH TIME
IT DWINDLES TO 4000-5000FT OR LESS. THIS EVENING...EXPECT SNOW
SHOWER ACTIVITY WITH LIGHT ACCUMULATIONS (INCH OR LESS) ACROSS
CENTRAL LOWER MICHIGAN AND POSSIBLY ALONG THE HIGHWAY 131 CORRIDOR
(GIVEN THE STIFF WESTERLY WINDS DISPLACING BANDS INLAND A BIT). A
WET WARM GROUND WILL COUNTERACT THE SNOW SHOWERS SOME.
RELATIVE HUMIDITY IS QUITE LACKING IN THE OVERNIGHT THROUGH FRIDAY
EVENING TIME FRAME AND THEREFORE NOT EXPECTING MUCH IN THE WAY OF
SNOW SHOWERS DESPITE DELTA T/S IN THE MIDDLE TEENS C.
A COUPLE OF SHORTWAVE TROUGHS ROTATE THROUGH THE REGION FRIDAY NIGHT
INTO SATURDAY WHICH SHOULD GIVE A BOOST TO LAKE EFFECT CLOUDS AND
SNOW SHOWERS. SOME MINOR ACCUMULATIONS ARE POSSIBLE ALONG AND WEST
OF HIGHWAY 131. ENVISION DUSTING TO HALF INCH ACCUMS IN MOST
AREAS...BUT SOME LOCALIZED ACCUMS OF AN INCH OR TWO WILL BE
POSSIBLE.
&&
.LONG TERM...(340 PM EST THU DEC 15 2011)
(SUNDAY THROUGH THURSDAY)
SUNDAY LOOKS DRY AS A SFC HIGH AND NW FLOW ALOFT PRODUCES SOME
SUNSHINE ACROSS THE GREAT LAKES.
MODELS CONTINUE TO BE ON DIFFERENT PAGES WRT THE SRN STREAM LOW
MONDAY AND TUESDAY. BOTH THE ECMWF/GFS SHOW A SRN STREAM SHORT WAVE
BEING KICKED NEWD BY A NRN STREAM WAVE. THE ECMWF HOWEVER TAKES THE
LOW MORE EWD THROUGH THE OHIO VALLEY VS THE GFS THAT TAKES THE LOW
OVER LWR MI. BASED ON THE UPPER WAVE TRACK I TEND TO BUY THE GFS
TRACK MORE. THIS TRACK WOULD ALSO BRING WARMER AIR INTO THE CWA.
THUS WE/LL KEEP THE RAIN/SNOW MIX MON-TUE NIGHT. LIGHT SNOW POSSIBLE
ON THE BACK SIDE OF THE SYSTEM WEDNESDAY AS H8 TEMPS FALL TO -5C IN
NW FLOW. TEMPS WILL CONTINUE TO BE A FEW DEGREES WARMER THAN NORMAL
THROUGH THE PERIOD.
&&
.AVIATION...(640 PM EST THU DEC 15 2011)
WINDS WILL BE AN ISSUE THIS EVENING WITH MANY SITES GUSTING OVER 25
KNOTS. THESE STRONG WIND GUSTS COMBINED WITH COLD AIR ADVECTION
WILL LEAD TO TURBULENT MIXING. THE WINDS WILL SETTLE DOWN MAINLY
AFTER 03Z. MVFR CONDITIONS WILL PREVAIL THROUGH THE EVENING...BUT
IMPROVEMENT TO VFR IS EXPECTED AS DRIER AIR MOVES IN FROM THE WEST
BY NOON FRIDAY. A FEW RAIN SHOWERS ARE EXPECTED THIS EVENING...AND
SOME OF IT WILL BE SNOW UP TOWARD KRQB AND KHTL.
&&
.MARINE...(340 PM EST THU DEC 15 2011)
WILL MAINTAIN THE GALE WARNING THROUGH THIS EVENING AS THE CORE OF
THE WIND LOOKS TO COME THROUGH BETWEEN 400PM AND 1000PM. WE WILL
EXTEND THE GALE SLIGHTLY TO GIVE A LITTLE BIT OF A BUFFER ON THE
BACK END...THROUGH 100 AM. RUC OVERVIEW/S ALONG THE
COAST ARE SHOWING 40 KNOTS OF WIND DOWN TO AROUND 1000FT...WHICH
SHOULD TRANSLATE INTO FREQUENT GALE FORCE GUSTS AT THE COASTAL
SITES. WINDS WILL DROP BELOW GALE FORCE AFTER MIDNIGHT AND WE WILL
NEED A SMALL CRAFT ADVISORY THAT WILL STRETCH INTO THE DAYLIGHT
HOURS OF FRIDAY. SUB SMALL CRAFT ADVISORIES CONDITIONS ARE EXPECTED
FROM FRIDAY EVENING INTO SUNDAY.
&&
.HYDROLOGY...(340 PM EST THU DEC 15 2011)
ONE RIVER FLOOD WARNING (VICKSBURG) AND THREE RIVER FLOOD ADVISORIES
(IONIA...BURLINGTON AND HOLT) ARE CURRENTLY IN EFFECT. WE ARE NOT
EXPECTING MUCH IN THE WAY OF CHANGES TO RIVER HEADLINES AT THIS
POINT GIVEN THE RAINFALL HAS OCCURRED AND IS MAKING IT/S WAY INTO
THE RIVERS. RAINFALL TOTALS RANGED FROM A HALF INCH TO SLIGHTLY OVER
ONE INCH FOR THE LAST 24 HOURS OR SO. COLDER AIR IS NOW SURGING INTO
THE AREA AND THIS WILL ACT TO SLIGHTLY SUPPRESS RUN OFF SLIGHTLY.
SO...BOTTOM LINE RISES WILL CONTINUE THE NEXT COUPLE OF DAYS WITH
MOST SITES IN THE AREA REMAINING UNDER BANKFULL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY LAKESHORE COUNTIES THROUGH 1100 PM.
LM...GALE WARNING ENTIRE NEARSHORE AREA THROUGH 100 AM.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: 93
AVIATION: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EST WED DEC 14 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS
AND A RIDGE OVER THE SE WITH MAINLY ZONAL FLOW FROM THE NRN PLAINS
TO NEW ENGLAND. A VIGOROUS SHORTWAVE TROUGH WAS MOVING THROUGH AZ
WHILE A WEAKER UPSTREAM SHRTWV WAS MOVING INTO SRN SD. AT THE
SFC...A RIDGE EXTENDED FROM NORTHERN QUEBEC TO LAKE SUPERIOR
RESULTING IN WEAK ACYC FLOW OVER THE CWA WITH NO PCPN INDICATED BY
RADAR. WITH THE MILD/MOIST AIRMASS IN PLACE...PATCHY FOG LINGERED
OVER LOCATIONS NEAR THE WI BORDER.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY
TONIGHT...AS THE HIGH SLIDES OFF TO THE SE...SRLY LOW LEVEL FLOW
WILL INCREASE WEAK UPSLOPE FLOW INTO PORTIONS OF WEST AND CENTRAL
UPPER MI MAY BE ENOUGH TO SUPPORT SOME PATCHY -DZ/-FZDZ AFT 06Z EVEN
THOUGH OVERALL LOW LEVEL (925-850 MB) LIFT IS VERY WEAK...PER
NAM/RUC...280K ISENTROPIC PROGS. OTHERWISE...WITH LITTLE DIURNAL
TEMP CHANGE IS EXPECTED OVER THE AREA. AREAS OF FOG...SOME LCLY
DENSE...MAY ALSO THICKEN WITH SLIGHT INCREASE IN MOISTURE ADVECTION.
WEDNESDAY...AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND MOVES
TOWARD THE UPPER MS VALLEY...LOW/MID LEVEL WAA AND MOISTURE
ADVECTION WILL INCREASE. THIS SHOULD BRING AN AREA OF LIGHT PCPN
OVER THE ENTIRE CWA BY AFTERNOON...PER NAM/GFS 290K-295K ISENTROPIC
PROGS. NAM WET-BULB ZERO HEIGHTS SUGGEST THAT THE PCPN SHOULD BE
MAINLY RAIN. HOWEVER...GIVEN LOW LEVEL TEMP PROFILES NEAR 0C OVER
THE INTERIOR WEST...CANNOT RULE OUT SOME SNOW. ANY ACCUMULATIONS
WOULD BE MINIMAL. EVEN THOUGH TEMPS WILL BE ABOVE FREEZING WHEN THE
RAIN ARRIVES...SOME UNTREATED ROADS MAY STILL BE COLD ENOUGH TO
CREATE PATCHY ICY SPOTS.
.LONG TERM /WED NIGHT THROUGH NEXT TUESDAY/...
SHORTWAVE CURRENTLY ROUNDING THE UPPER TROUGH OFF THE COAST OF SRN
CA WILL MOVE TOWARDS THE AREA LATE WED AFTN AND MOVE ACROSS THE AREA
WED EVENING. MODELS FAIRLY CONSISTENT ON THE MAIN ENERGY FROM THE
SHORTWAVE MOVING ACROSS CNTRL/ERN UPPER MI...WHICH WILL GRADUALLY
INTENSIFY THE LOW MOVING FROM IOWA AT 00Z THURS TO SE ONTARIO AT 12Z
THURS. OTHER THAN THE FAST AND NW OUTLIER 12Z NAM...MAIN DIFFERENCES
BETWEEN THE MODELS IS IN THE INTENSITY OF THE LOW. 06-12Z GFS RUNS
ON THE STRONG SIDE AND 00Z ECMWF ON WEAKER SIDE. WILL FOLLOW A BLEND
OF THE TWO SINCE TRACKS ARE SIMILAR AND ONLY MINOR DIFF IN THE
THERMAL PROFILES.
DURING THE EVENING...06 AND 12Z GFS SHOWING STRONG FGEN FROM
H800-400 ACROSS THE CWA. THINK THE BEST FORCING WILL BE ALONG THE
H800-600 FGEN AREA...WHERE THERE IS ABUNDANT MOISTURE AND STRONG
AGEOSTROPHIC UPWARD CIRCULATION. FARTHER NW...APPEARS TO BE A DECENT
H700-500 DRY AIR LAYER...AND DOWNWARD CIRCULATION MAY LIMIT PCPN
FARTHER NW TOWARDS A KIWD TO KCMX LINE. OVER THE E...EXPECT A STRONG
AREA OF H850-700 WAA AND 285-300K SFC ISENTROPIC ASCENT DURING THE
EVENING. THINK THE EXISTING 100 POPS LOOK GOOD AND WILL LEAVE THEM
AS IS. THEN HAVE A GRADUAL LOWERING HEADING OVER THE WEST TOWARDS
HIGH END LIKELY. COULD BE A SHARP CUTOFF TO THE WEST EXTENT OF THE
PCPN OVER THE WRN HALF OF LK SUPERIOR WITH THE FGEN CIRCULATION...SO
TRIED TO SHOW THAT POTENTIAL.
P-TYPE FOR THE WED NIGHT PERIOD IS WHERE THINGS GET TRICKY. BUFKIT
SOUNDINGS FROM THE GFS SHOW AN ISOTHERMAL PROFILE FROM SFC TO
5-6KFT. WITH THAT TYPE OF SITUATION...IT WILL LIKELY BE SNOW WHERE
LAYER IS NEAR 0C AND THEN RA/SN AROUND 1C AND ALL RA AROUND 2-3C.
KCMX MAY BE FAR ENOUGH N AND AWAY FROM THE WARM SURGE TO KEEP PCPN A
RA/SN MIX OR POSSIBLY EVEN ALL SNOW. THEN HEADING S AND E ACROSS THE
CWA...EXPECT A TRANSITION TO ALL RAIN. BIGGEST CONCERN IS GETTING
THAT RA/SN AREA PINNED DOWN AND STILL DON/T HAVE A GREAT FEEL...BUT
IT SHOULD BE OVER THE NW THIRD. FORTUNATELY...THE HEAVIEST QPF WILL
LIKELY BE TO THE SE OF THE UNCERTAIN AREA FOR RA/SN...SO IT SHOULD
LIMIT THE IMPACT IF IT DOES END UP ALL SNOW.
LAST COUPLE OF RUNS OF THE GFS HAVE REALLY BUMPED UP THE QPF IN THE
FGEN LOCATION MOVING ACROSS CNTRL UPPER MI...WITH LIQUID AMOUNTS
EXCEEDING 0.75IN...BUT IT IS LIKELY DUE TO THE MORE WRAPPED UP LOW
SOLN. WILL NOT GO THAT HIGH...BUT WILL NEED TO BE MONITORED IF
STRONGER LOW SOLN PANS OUT. OTHERWISE...EXPECT 0.25 TO 0.4 OF LIQUID
ACROSS THE SE HALF OF THE CWA...MAINLY DURING THE EVENING.
MAIN ENERGY AND DEEPER H700-500 MOISTURE PULLS OUT OVERNIGHT WED AND
HAVE DIMINISHING POPS TO ACCOUNT FOR THAT. P-TYPE IS AGAIN A CONCERN
HEADING INTO THE OVERNIGHT...SINCE THE DEEPER MOISTURE PULLS OUT
BEFORE THE COLDER AIR ARRIVES LATE WED NIGHT INTO THURS. THIS WILL
CUT THE POTENTIAL FOR ICE CRYSTALS IN THE CLOUD WAY DOWN AND LIMIT
THE POTENTIAL FOR SNOW. WITH TEMPERATURES DROPPING TOWARDS FREEZING
OVER THE WEST TOWARDS 12Z THURS...DID KEEP A MENTION OF -FZRA IN THE
FORECAST LATE...BUT POTENTIAL SEEMS LIMITED DURING THE OVERNIGHT
HOURS WITH THE SHORT PERIOD OF AT OR BELOW FREEZING TIME.
OTHERWISE...WILL ONLY MENTION A LOW CHANCE FOR SNOW OVER THE WEST
OVERNIGHT DUE TO LIMITED ICE CRYSTAL PRESENCE AND RAIN OVER THE
CENTRAL AND EAST. THINK THE BIGGEST HAZARD IS MORE LIKELY TO BE THE
WET ROADS ICING UP ON THURS...AS TEMPS FALL BELOW FREEZING THROUGH
THE DAY.
NRN STREAM UPPER TROUGH WILL SWEEP THROUGH THE CWA ON THURS. STILL
DIFFERENCES IN THE SPEED/INTENSITY IN THE MODELS WITH THIS
WAVE...BUT ALL HAVE THE GENERAL IDEA OF IT MOVING THROUGH THE UPPER
GREAT LKS ON THURS. THIS WAVE WILL DROP H850 TEMPS THROUGH THE DAY
TO -12C OVER THE W BY 00Z FRI. THESE COLDER TEMPS WILL STAY OVER THE
AREA THROUGH THE DAY FRI...ANOTHER WEAKER SHORTWAVE DROPS ACROSS THE
AREA. WITH TEMPS ALOFT PUTTING THE CLOUD LAYER BACK INTO THE ICE
CRYSTAL AREA ON THURS...EXPECT TO CHANCES FOR SNOW AS THE P-TYPE TO
BE ON THE INCREASE FROM WEST TO EAST. SHORTWAVE ENERGY WILL HELP
ENHANCE THE DEVELOPING LES THROUGH THE DAY. WILL CONTINUE TREND OF
HIGHER POPS OVER THE WEST IN THE MORNING WITH LES DEVELOPING AND
SHORTWAVE ARRIVING...THEN INCREASE LES POPS OVER THE E UNDER NW
WINDS IN THE AFTN INTO THURS NIGHT. IN ADDITION...WITH THE LOW
INTENSIFYING TO THE NE OF THE AREA...EXPECT A BREEZY DAY ON THURS
ACROSS THE AREA. THE HIGHEST WINDS SHOULD BE OVER THE E NEAR LK
SUPERIOR...WHERE WINDS COULD GUST TO 40-45MPH LATE IN THE AFTERNOON.
SFC RIDGE QUICKLY MOVES FROM W TO E OVER THE CWA ON THURS NIGHT INTO
FRI. MODELS SHOWING VERY PRONOUNCED H925-700 DRYING WITH THE ARRIVAL
OF THE RIDGE...SO HAVE TRENDED BACK LES POPS...ESPECIALLY OVER THE
WEST WHERE BUFKIT SOUNDINGS SHOWING INVERSION HEIGHTS FALLING
TOWARDS 3KFT. DID KEEP LIKELY/S OVER THE NW WIND FAVORED E LOCATIONS
THURS NIGHT INTO FRI MORNING...BUT DROPPED TO CHANCES IN THE AFTN AS
THE DRY AIR LIMITS POTENTIAL.
DAYS 4 THROUGH 7 /FRI NIGHT THROUGH NEXT TUESDAY/...
WEAK SHORTWAVE MOVING ACROSS THE AREA FRI NIGHT WILL BRING A LITTLE
MORE MOISTURE TO THE AREA AND KEEP COLDER AIR IN PLACE. EXPECT
ONGOING LES TO CONTINUE OVER THE E...WITH WINDS GRADUALLY SHIFTING
MORE WRLY. LES MAY TRY TO REDEVELOP OVER THE W WITH THE ARRIVAL OF
THE SHORTWAVE AND ADDITIONAL LLVL MOISTURE. WILL GO WITH LOW CHANCES
OVER THE KEWEENAW WITH THE MORE WRLY WINDS AND THEN LOW END LIKELY/S
OVER THE EAST.
UPPER TROUGH SHIFTS E ON SAT AND DRAGS A SFC TROUGH OVER NRN LK
SUPERIOR AND SRN ONTARIO THROUGH THE DAY AND INTO SAT NIGHT. THERE
HAS BEEN A STRONGER TREND WITH THE SFC FEATURES AND UPPER FORCING
OVER THE LAST DAY FOR THE SAT AND SAT NIGHT PERIOD...SO HAVE BUMPED
POPS UP TO SLIGHTS OVER THE NRN U.P. AND CHANCES OVER THE LAKE.
SOME DIFFERENCES APPEAR IN THE EXTENDED MODELS ON SUN INTO MON WITH
THE HANDLING OF A POTENTIAL RIDGE IN THE NRN STREAM AND A CLOSED LOW
OVER THE SW CONUS. LATEST 12Z RUN OF THE GFS HAS TRENDED SLOWER WITH
THE EXIT OF THE UPPER LOW OVER THE SW CONUS SUN INTO MON...AND MORE
IN LINE WITH THE 00Z ECMWF...SO HAVE FOLLOWED THAT FOR THE REST OF
THE EXTENDED. SFC RIDGE WILL MOVE ACROSS THE CWA ON SUN INTO SUN
NIGHT. NRN STREAM SHORTWAVE WILL APPROACH THE AREA MON INTO
TUES...BRINGING ANOTHER LOW CHANCE OF PCPN. HAS BEEN A GOOD AMOUNT
OF FLUCTUATION IN H850 TEMPS AFTER SUN...SO HAVE LIMITED CONFIDENCE
IN VALUES...BUT APPEARS THAT TEMPS WILL SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
LOW-LEVELS WILL REMAIN MOIST THROUGH THE TAF PERIOD AS A LOW
PRESSURE SYSTEM OVER THE CENTRAL PLAINS LIFTS NORTH INTO THE UPPER
GREAT LAKES ON WEDNESDAY. LIMITED MIXING TONIGHT...MOIST LOW-LVLS
AND LIGHT UPSLOPE SE FLOW SHOULD LEAD TO LIFR TO VLIFR CONDITIONS IN
STRATUS/FOG AT KSAW. TRICKIER FCST IN STORE FOR KCMX AND KIWD
OVERNIGHT AS SE FLOW IS MORE DOWNSLOPE FOR THESE LOCATIONS WHICH
COULD MITIGATE STRATUS/FOG. LOOK FOR ONLY IFR CONDITIONS AT KCMX AND
VFR TO POSSIBLY MVFR CIGS AT KIWD.
IN GENERAL...SIGNIFICANT IMPROVEMENT IS NOT ANTICIPATED THROUGH
WEDNESDAY MORNING AT ANY OF THE TAF SITES. RAIN IS EXPECTED BY WED
AFTERNOON AS SYSTEM APPROACHES FROM THE CENTRAL PLAINS. THIS
ADDITIONAL MOISTURE FROM THE RAIN COMBINED WITH A SHIFT TO MORE
WESTERLY UPSLOPE WINDS BEHIND THE LOW PRES SYSTEM WILL LIKELY LOWER
CONDITIONS TO LIFR OR VLIFR AT BOTH KCMX AND KIWD BY WED EVENING. AT
KSAW...EXPECT LIFR CONDITIONS TO LOWER TO VLIFR BY LATE WED
AFTERNOON IN CONTINUED MOIST UPSLOPE FLOW. ONLY CHANCE FOR MARGINAL
IMPROVEMENT WOULD BE A SHIFT TO WRLY WINDS LATE EVENING BEHIND THE
SYSTEM/S COLD FRONT.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LIGHT SOUTHERLY WINDS WILL INCREASE INTO THE 15 TO 25 KT RANGE OVER
THE CENTRAL AND EAST PORTIONS OF THE LAKE WED AHEAD OF LOW PRESSURE
DEVELOPING IN THE PLAINS. THE LOW IS FCST TO DEEPEN AS IT LIFTS
ACROSS THE UPPER LAKES BY THURSDAY MORNING. STRONGEST WINDS THIS
WEEK WILL OCCUR JUST IN THE WAKE OF THE LOW THURSDAY MORNING THROUGH
MIDNIGHT THURSDAY NIGHT. CONFIDENCE THAT 35-40 KT GALES WILL OCCUR
IS HIGH SO THE WATCH CONTINUES FOR MUCH OF LK SUPERIOR. STRONG WINDS
WILL DIMINISH ON FRI WITH THE SLOW APPROACH OF A HIGH PRESSURE
RIDGE. A STRONGER SW FLOW WILL REDEVELOP ON SAT AFTER THIS HIGH
SHIFTS TO THE SE WITH WINDS TO AROUND 30 KT OVER WEST AND CENTRAL
PORTIONS OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
LSZ264>267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...VOSS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1235 PM CST WED DEC 14 2011
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING
THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN
AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND
WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW
LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE
ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT
THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING
OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE
MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE.
FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW
MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE.
MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN.
THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE
SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING
BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING
THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY
TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB
HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN
INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL
WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE
IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT
OF NORMAL THROUGH THE CENTRAL PLAINS.
BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD
ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME
AREAS.
THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS
WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT
CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO
EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT
SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE
SOUTHWEST..EAST OF THE BUFFALO RIDGE.
ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID
WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE
TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE
SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE
WITH THIS ONE.
&&
.AVIATION.../18Z TAF ISSUANCE/
DEEP UPPER TROUGH OVER THE THE CENTRAL CONUS SENDING A SWARM OF
SHORTWAVES OUR DIRECTION AND WILL CONTINUE TO KEEP SIMPLY UGLY
CONDITIONS IN PLACE...WITH WIDESPREAD LIFR/IFR CONDITIONS EXPECTED
TO PERSIST AT ALL LOCATION THROUGH AT LEAST 06Z. THROUGH TONIGHT...
A RWF TO SIREN...WI LINE WILL BE A GOOD SEPARATION OF EXPECTED
WEATHER. NW OF THIS LINE...DENSE FOG HAS BEEN IN PLACE ALL
MORNING. GFSLAMP FROM BOTH AXN/STC KEEP 1/2SM OR LESS VSBY IN
PLACE THROUGH 6Z. DID NOT KEEP VIS THAT LOW FOR THAT LONG IN
THESE TAFS...AS WAVE MOVING ACROSS THE CENTRAL DAKOTAS HAS BE
SPREADING DZ/SN/RA EAST. THIS PRECIP SHOULD REACH CENTRAL/WRN MN
AROUND 00Z WITH THE HOPE THAT AS IT DOES SO...THE PRECIP WILL HELP
MIX THINGS ENOUGH TO GET THE VSBYS ABOVE 1/2SM. SE OF THE
AFOREMENTIONED LINE...RA AND DZ WILL DOMINATE THE WEATHER THROUGH
06Z. CIGS SHOULD REMAIN AT OR BELOW 005 DURING THIS TIME...BUT THE
FALLING RAIN WILL HELP HOLD VSBYS UP TO BETWEEN 2SM AND 4SM.
P-TYPE WITH THIS LOOKS TO REMAIN MOSTLY RAIN...BUT BETWEEN 3Z AND
6Z A TRANSITION TO SNOW WILL BE POSSIBLE...BUT BY THEN THE PRECIP
WILL BE MOVING OUT. ESTABLISHMENT OF W/NW WINDS AFTER 00Z FROM
WEST TO EAST WILL HELP CLEAN OUT THE FG AND RAIN TONIGHT...BUT IFR
CIGS LOOK TO REMAIN IN PLACE MOST OF THE NIGHT. GOING INTO
THURSDAY MORNING...STRONG CAA MOVING IN FROM THE NW DURING THE
MORNING WILL ALSO BRING ALONG A REINFORCING SHOT OF
STRATUS...THOUGH BY THEN CIGS SHOULD IMPROVE TO MVFR LEVELS.
KMSP...LOOKING AT LATEST RADAR TRENDS...-RA LOOKS TO BE THE
PREDOMINATE PLAYER FOR THE NEXT FEW HOURS. MPXWRF/HRRR
REFLECTIVITY FORECASTS BOTH HANDLING THIS PRECIP WELL...WITH THE
BULK OF IT MOVING EAST OF MSP AFTER 04Z. FORECAST SOUNDINGS OFF THE
RUC/GFS SHOW IT BECOMING COLD ENOUGH OF SN BETWEEN 3Z AND
6Z...BUT BY THEN MAJORITY OF PRECIP LOOKS TO BE EAST OF FIELD...SO
ONLY HAVE A VCSH MENTION FOR NOW...BUT THERE COULD BE A BRIEF 2 OR
3 HOUR PERIOD WHERE -SN IS OBSERVED. RH PROFILE OFF THE NAM KEEPS
IFR CIGS IN PLACE THROUGH 12Z...AND GIVEN EXTENT OF CLOUDS TO THE
WEST...FAVORED A SLOWER SOLUTION FOR IMPROVING THINGS TO MVFR. CAA
DURING THE COURSE OF THE DAY THURSDAY SHOULD KEEP AT LEAST MVFR
CIGS IN PLACE INTO THE AFTERNOON...BUT HOPEFULLY WE WILL GET TO
SEE SOME SUN LATE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
647 AM CST WED DEC 14 2011
.UPDATE...
UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING
THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN
AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND
WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW
LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE
ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT
THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING
OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE
MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE.
FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW
MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE.
MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN.
THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE
SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING
BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING
THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY
TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB
HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN
INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL
WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE
IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT
OF NORMAL THROUGH THE CENTRAL PLAINS.
BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD
ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME
AREAS.
THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS
WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT
CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO
EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT
SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE
SOUTHWEST..EAST OF THE BUFFALO RIDGE.
ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID
WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE
TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE
SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE
WITH THIS ONE.
&&
.AVIATION.../12Z TAF ISSUANCE/
WITH LIFR CEILINGS ALMOST EVERYWHERE...THE CLOUD BASE FORECAST IS
ACTUALLY NOT ALL THAT CHALLENGING FOR THE FIRST 6 HOURS. WITH THE
BROAD SURFACE TROF SETTLING IN AND A NICE FETCH OF MOISTURE FROM
THE SOUTHEAST...THESE CEILINGS AREN`T GOING ANYWHERE FOR MOST FOR
THE DAY. ITS POSSIBLE SOME SPOTS SEE THE DECK LIFT 200-400FT BY THIS
AFTERNOON...BUT SHOULD STILL REMAIN IFR. THE VISIBILITY FORECAST
IS MORE CHALLENGING GIVEN THE AREAS OF FOG AND DRIZZLE MIXED WITH
SCATTERED LIGHT RAIN SHOWERS. EVEN THOUGH IT FLIES IN THE FACE OF
CLIMATOLOGY...WORRIED THAT THE VISIBILITY MAY ACTUALLY GET WORSE
DURING A FEW HOUR WINDOW LATE THIS MORNING/THIS
AFTERNOON...ESPECIALLY IF THE RAIN HANGS TO OUR SOUTH FOR A WHILE.
WINDS SHOULD DECREASE UNDER THE TROF AND MAY GO CALM. PLENTY OF
1/4SM AND 1/2SM VISIBILITIES IN EASTERN SD AND WESTERN MN THIS
MORNING. BETTER CHANCES FOR LIGHT RAIN IN SOUTHEAST MN AND WESTERN
WI TODAY...WITH THE CHANGE OVER TO SNOW HAPPENING SOMETIME LATE
THIS EVENING.
KMSP...VISIBILITIES BELOW 2SM AND CEILINGS UNDER 500FT ARE NOT
GOING ANYWHERE FOR THE NEXT 6 HOURS. IN FACT...HAVE INCLUDED A
TEMPO GROUP FOR 1/2SM FOG EARLY THIS AFTERNOON WHEN WINDS DECREASE
AND MAY GO CALM FOR A TIME BEFORE TURNING TO THE WEST/NORTHWEST
LATE THIS EVENING. DON`T HAVE SUPREME CONFIDENCE WE`LL BUCK
CLIMATOLOGY AND SEE VISBYS DECREASE IN THE AFTERNOON...BUT THESE
ARE THE TYPES OF SITUATIONS WHEN IT DOES INDEED HAPPEN. THE WILD
CARD IS THE RAIN SHOWERS...WHICH WHEN PRESENT WOULD ACTUALLY KEEP
THE VISBYS FROM DROPPING TOO LOW. RIGHT NOW THE CHANGE OVER TO
SNOW TO ANY REMAINING PRECIPITATION WILL LIKELY SOMETIME AROUND
MIDNIGHT...WITH THE SURFACE AIR TEMPERATURE FALLING BELOW FREEZING
3-4 HOURS LATER.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
402 AM CST WED DEC 14 2011
.DISCUSSION...
A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING
THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN
AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND
WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW
LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE
ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT
THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING
OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE
MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE.
FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW
MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE.
MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN.
THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE
SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING
BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING
THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY
TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB
HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN
INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL
WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE
IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT
OF NORMAL THROUGH THE CENTRAL PLAINS.
BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD
ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME
AREAS.
THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS
WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT
CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO
EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT
SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE
SOUTHWEST..EAST OF THE BUFFALO RIDGE.
ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID
WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE
TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE
SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE
WITH THIS ONE.
&&
.AVIATION... /06Z TAF ISSUANCE/
VFR CONDITIONS OVER EASTERN AREAS WILL GRADUALLY GIVE WAY TO IFR
CONDITIONS OVER THE NEXT FEW HOURS AS LIGHT RAIN GRADUALLY SATURATES
LOWER LEVELS OF THE ATMOSPHERE. LIGHT RAIN/DRIZZLE TO CONTINUE INTO
THE EARLY MORNING BEFORE TAPERING AS INITIAL SURGE OF FORCING MOVES
THROUGH. WILL SEE INCREASING THREAT LIGHT RAIN DEVELOPING WED
AFTERNOON AS SURFACE FRONT AND UPPER TROUGH MOVES THROUGH. THIS
SLIDES EAST BY EARLY EVENING WITH PERHAPS SOME RAIN/SNOW CHANGING TO
SNOW OVER EASTERN AREAS THROUGH 06Z THU. WILL GRADUALLY LIFT
CEILINGS AND END PRECIPITATION FROM WEST TO EAST DURING THE NIGHT.
LIGHT SOUTHEAST WIND FLOW AHEAD OF FRONT...BECOMING NORTHWEST WITH
FROPA.
KMSP...VFR CIGS GRADUALLY LOWERING TO IFR THROUGH THE EARLY MORNING.
LIGHT RAIN SHOULD TAPER OR END AS DRIZZLE EARLY MORNING. AS UPPER
TROUGH AND SURFACE FRONT APPROACHES...INCREASING CHANCE OF LIGHT
RAIN DEVELOPING IN THE AFTERNOON/EARLY EVENING....PERHAPS ENDING AS
A LIGHT RAIN/SNOW MIX BEFORE 06Z THU.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/DWE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
720 AM CST WED DEC 14 2011
.UPDATE...DID A QUICK UPDATE TO DECREASE SKY COVER A TAD FOR LATE
MORNING/THIS AFTERNOON. LATEST RUC GUIDANCE INITIALIZED VERY WELL
BASED ON THE 12Z JAN RAOB...WITH THIS SAME GUIDANCE NOW MORE
SUGGESTIVE OF THE CLOUDS TRYING TO BREAK UP AFTER 1 PM. HIGH TEMPS
STILL LOOK GOOD THOUGH AND HAVENT MADE ANY ADJUSTMENTS...BUT THIS MAY
VERY WELL CHANGE ONCE THE EXTENT OF THE CLOUD COVER IS BETTER KNOWN
LATER THIS MORNING. /BK/
&&
.PREV DISCUSSION... /ISSUED 400 AM CST WED DEC 14 2011/
..DENSE FOG OCCURRING OVER PORTIONS OF THE ARKLAMISS THIS MORNING...
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...WIDESPREAD STRATUS
CONTINUES TO BLANKET THE ARKLAMISS THIS MORNING AS GENTLE MOIST
UPGLIDE OCCURS FROM THE SOUTHEAST. VISIBILITY RESTRICTIONS HAVE BEEN
A BIT EASIER TO COME BY TONIGHT AS OPPOSED TO LAST NIGHT...
ESPECIALLY ACROSS AREAS EAST OF I-55 AND ALONG THE HIGHWAY 82
CORRIDOR AND INTO SOUTHEAST AR. SURFACE OBSERVATIONS ACROSS THESE
AREAS SHOW FAIRLY WIDESPREAD RESTRICTIONS OF 1/2MI OR LESS AND WILL
GO WITH A DENSE FOG ADVISORY ACCORDINGLY...WHICH MEANT AN EXPANSION
OF THE CURRENT ADVISORY TO THE SOUTHEAST. LOOKING AT OBSERVATIONS
FROM YESTERDAY MORNING AND CLIMATOLOGY IT LOOKS LIKE THE VIS SHOULD
START COMING UP AFTER 9AM AND WILL END THE ADVISORY AT THAT TIME. A
SLOWLY INCREASING PRESSURE GRADIENT ACROSS SOUTHWESTERN ZONES
APPEARS TO BE LIMITING FOG POTENTIAL IN THIS AREA AS LATEST OBS FROM
HEZ/TVR/MCB/MLU INDICATE 5MI OR BETTER VIS. THE DENSE FOG ADVISORY
THAT WAS IN EFFECT FOR PORTIONS OF THIS AREA HAS BEEN CANCELLED AS A
RESULT. WILL KEEP A CLOSE ON THE FOG SITUATION THIS MORNING SO STAY
TUNED FOR UPDATES. WE MAY NEED TO EXPAND THE ADVISORY INTO THE
JACKSON METRO AT SOME POINT.
FOCUS THEN SHIFTS TO CLOUD COVER POTENTIAL THIS AFTERNOON AND HOW
THAT WILL IMPACT AFTERNOON HIGHS. LATEST RUC GUIDANCE IS NOT
CONFIDENT WE WILL SEE MUCH SUN THIS AFTERNOON AS LOW LEVEL MOISTURE
FIELDS REMAIN SATURATED FOR ALL BUT FAR EASTERN AREAS WHERE SOME
THINNING OF THE CLOUDS IS POSSIBLE. LATEST NAM/SREF INDICATE SOME
THINNING POSSIBLE NORTH OF I-20 THIS AFTERNOON REMAINING SOCKED IN
ELSEWHERE. OVERALL I LIKE WHAT THE RUC IS SHOWING AND HAVE
GENERALLY STUCK WITH CLOUDY SKIES TODAY FOR ALL AREAS...SHOWING A
FEW PEAKS OF SUN IN THE EAST THIS AFTERNOON. I DO HOWEVER THINK
THERE IS SOME POTENTIAL FOR A FEW BREAKS IN THE CLOUDS ACROSS THE
SOUTHWEST LATER ON AS THE LOW LEVEL FLOW PICKS UP IN RESPONSE TO A
PRESSURE GRADIENT THAT CONTINUES TO TIGHTEN. SO...WITH CLOUD COVER
REMAINING FAIRLY SOLID TODAY I HAVE GONE WITH THE LOWEST MEMBER OF
THE GFS MOS SUITE(MID TO UPPER 60S) FOR TEMPS TODAY...WHICH MIGHT
STILL BE TOO HIGH AS I THINK WE MIGHT STRUGGLE TO GET TO THE LOW 60S
ACROSS A BIG PORTION OF THE AREA.
TONIGHT INTO THURSDAY...A COLD FRONT WILL BE MOVING INTO SOUTH
CENTRAL AR LATE TONIGHT ATTENDANT TO A S/WV LIFTING ACROSS THE
CENTRAL PLAINS AND INTO THE GREAT LAKES REGION. LIGHT RAIN CHANCES
WILL BE ON THE INCREASE LATE TONIGHT/EARLY TOMORROW MORNING ACROSS
THE DELTA AS THIS FEATURE APPROACHES...WITH A FEW LIGHT NORTHWARD
MOVING SHOWERS AHEAD OF THE FRONT POSSIBLE ALONG/WEST OF THE MS
RIVER. THE FRONT WILL LIMP INTO MS LATE THURSDAY PUSHING SHOWER
CHANCES FURTHER SOUTHEAST AS IT ADVANCES. INSTABILITY IS RATHER WEAK
WITH THIS SYSTEM THANKS TO WARM MID/UPPER LEVEL TEMPS AND ASSOCIATED
WEAK LAPSE RATES. FORCING IS REAL WEAK AS WE REMAIN UNDER THE
INFLUENCE OF UPPER RIDGING ALOFT...ALL COMBINED I THINK THE
POTENTIAL FOR ANY STRONG TO SEVERE STORMS IS LOW THURSDAY. BUT...IF
THE INSTABILITY COMES IN A BIT HIGHER THAN FORECAST THERE COULD BE A
MARGINAL RISK OF 50MPH WIND GUSTS ACROSS THE FAR NORTHWEST EARLY TO
MID DAY THURSDAY. WILL GO AHEAD AND KEEP THAT MENTION IN THE HWO FOR
NOW. THE FRONT WILL STALL ACROSS CENTRAL PORTIONS OF THE FA THURSDAY
EVENING AS ANOTHER S/WV IN SOUTHWESTERLY FLOW LIFTS ACROSS THE
SOUTHERN PLAINS AND INTO THE MID MS VALLEY EARLY FRI. AS THIS BETTER
FORCING INTERACTS WITH THE FRONT WE COULD SEE A PERIOD OF MODERATE
RAIN THURSDAY NIGHT AS THE WAVE PASSES.
AS FOR TEMPS...LOWERED HIGHS FOR THURSDAY FOR MOST SITES AS CLOUD
COVER/RAIN POTENTIAL KEEP US FROM CLIMBING MUCH ABOVE
70...ESPECIALLY ACROSS THE DELTA WHERE WE PROBABLY WONT EVEN GET TO
70. OVERNIGHT LOWS SEEMED REASONABLE THIS PERIOD. /BK/
LONG TERM...FRIDAY THROUGH WEDNESDAY...TWO PERIODS OF RAIN ARE
EXPECTED IN THE LONG TERM. THIS FIRST IS FRIDAY AND THE SECOND IS
MONDAY NIGHT. COME FRIDAY MORNING A NEARLY STATIONARY COLD FRONT IS
EXPECTED TO BE ACROSS THE SOUTHEAST PORTION OF OUR CWA. THE NAM IS A
LITTLE FARTHER NORTH...BUT MODEL CONSENSUS PLACES THE FRONT FROM
SOUTH OF NATCHEZ TO JUST NORTH OF MERIDIAN AT SUNRISE. THERE IS
EXPECTED TO BE PLENTY OF POST FRONTAL PRECIPITATION ACROSS OUR CWA
AS A CLOSED LOW OVER THE DESERT SOUTHWEST DRAWS PACIFIC MOISTURE
ACROSS THE SOUTHERN PLAINS AND OUR REGION ON SOUTHWEST WINDS ALOFT.
A COUPLE OF NORTHERN STREAM SHORTWAVES WILL MOVE ACROSS THE PLAINS
FRIDAY AND SATURDAY AND HELP A +1030MB SURFACE HIGH DROP SOUTH TO
THE ARKLATEX REGION BY SATURDAY AFTERNOON. AS THIS HIGH DROPS SOUTH
THE NEARLY STATIONARY FRONT WILL BE PUSHED SOUTH OF OUR CWA AND THE
ASSOCIATED RAIN WILL END. THE BULK OF THE RAIN SHOULD END FROM THE
NORTH FRIDAY EVENING BUT A SLIGHT CHANCE OF RAIN WILL CONTINUE IN
THE SOUTH INTO SATURDAY MORNING. GUIDANCE POPS CAME IN A LITTLE HIGH
AND TOO FAR NORTH. HAVE CUT GUIDANCE POPS ACROSS OUR CWA SATURDAY
THROUGH SUNDAY. TEMPERATURES WILL BE WELL ABOVE NORMAL FRIDAY SOUTH
OF THE FRONT AND NEAR NORMAL NORTH OF THE FRONT. COOLER...BUT NEAR
NORMAL TEMPERATURES ARE EXPECTED SATURDAY. THE SURFACE HIGH WILL
BECOME CENTERED OVER OUR CWA SUNDAY MORNING AND CONTINUE SHIFTING
EAST DURING THE DAY. INDUCED RIDGING ALOFT WILL STRENGTHEN OVERHEAD
DUE TO THE CLOSED LOW MOVING JUST SOUTH OF THE FOUR CORNERS REGION.
THIS RIDGING SURFACE AND ALOFT SHOULD ALLOW TEMPERATURES TO RECOVER
NICELY SUNDAY AND TOP OUT ABOVE NORMAL AGAIN. HIGHS WILL BE IN THE
LOW TO MID 60S. RIDGING SURFACE AND ALOFT WILL SHIFT EAST MONDAY AS
THE CLOSED LOW MOVES TO THE SOUTHERN PLAINS. WAA WILL STRENGTHEN
OVER OUR CWA AHEAD OF THE APPROACHING SYSTEM LEADING TO RAIN CHANCES
INCREASING FROM THE WEST MONDAY. THE GFS AND ECMWF DISAGREE ON THE
PROGRESSION OF THE LOW MONDAY AND TUESDAY. THE GFS MAINTAINS THE
CLOSED LOW AND LIFTS THE BOTH THE UPPER LEVEL LOW AND SURFACE LOW
SLOWLY ACROSS THE OZARKS MONDAY NIGHT AND OVER THE TENNESSEE VALLEY
BY TUESDAY MORNING. THE MORE PROGRESSIVE ECMWF OPENS UP THE CLOSED
LOW AND MOVES BOTH THE UPPER LEVEL TROUGH AND SURFACE LOW TO THE
UPPER GREAT LAKES REGION BY TUESDAY MORNING. BOTH SCENARIOS BRING A
COLD FRONT WITH WIDESPREAD RAIN TO OUR CWA MONDAY NIGHT INTO TUESDAY
BUT THE GFS PARAMETERS SUGGEST THE POSSIBILITY FOR SEVERE WEATHER
MONDAY NIGHT FOR OUR CWA. WITH SUCH MODEL DISCREPANCIES WL HOLD OFF
INTRODUCING MENTION OF SEVERE WEATHER POTENTIAL IN THE HWO BUT LOOK
TO FUTURE RUNS FOR SOME CONTINUITY AND A MORE LIKELY CONSENSUS.
WEDNESDAY CURRENTLY LOOKS TO BE COOLER AND DRY FOR OUR REGION. /22/
&&
.AVIATION...
WDSPRD IFR CIG ARE PLAGUING THE REGION THIS
MORNING...ACCOMPANIED BY VRBL VSBYS RANGING FROM 1/4 TO 6SM. CIG
WILL LIKELY VARY BETWEEN 100 AND 800 FT UNTIL 17Z AT MOST SITES.
CLIMATOLOGY SUGGESTS CIG WILL TREND MVFR BY 18-19Z ALTHOUGH
CONFIDENCE IS LOW IN THIS BEING WDSPRD AS WE STRUGGLED TO LIFT MVFR
YESTERDAY. BEST CHANCE OF SEEING ANY SCT LOW CLOUDS WILL BE AT
MEI/HEZ THIS AFTN BUT THIS WILL PROB BE SHORT IF IT OCCURS AS IFR
CIG RETURN THIS EVENING. VIS WILL TREND MVFR 13-14Z BUT A TREND BACK
TOWARD IFR VSBY IS LIKELY TONIGHT. SFC WINDS WILL BE OUT OF THE SE
TODAY BECMG SRLY TONIGHT. /BK/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 68 59 72 57 / 0 13 48 82
MERIDIAN 70 54 74 59 / 0 10 37 74
VICKSBURG 69 60 71 52 / 1 22 69 84
HATTIESBURG 69 57 76 58 / 4 10 25 49
NATCHEZ 70 63 74 55 / 1 16 63 83
GREENVILLE 66 59 67 48 / 3 43 78 81
GREENWOOD 67 62 69 51 / 1 31 75 80
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ018-019-
025>039-044>046-050>052-056>058-065-066-073-074.
LA...NONE.
AR...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ARZ074-075.
&&
$$
BK/22
AREA FORECAST DISCUSSION
NWS JACKSON MS
400 AM CST WED DEC 14 2011
...DENSE FOG OCCURRING OVER PORTIONS OF THE ARKLAMISS THIS MORNING...
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...WIDESPREAD STRATUS
CONTINUES TO BLANKET THE ARKLAMISS THIS MORNING AS GENTLE MOIST
UPGLIDE OCCURS FROM THE SOUTHEAST. VISIBILITY RESTRICTIONS HAVE BEEN
A BIT EASIER TO COME BY TONIGHT AS OPPOSED TO LAST NIGHT...
ESPECIALLY ACROSS AREAS EAST OF I-55 AND ALONG THE HIGHWAY 82
CORRIDOR AND INTO SOUTHEAST AR. SURFACE OBSERVATIONS ACROSS THESE
AREAS SHOW FAIRLY WIDESPREAD RESTRICTIONS OF 1/2MI OR LESS AND WILL
GO WITH A DENSE FOG ADVISORY ACCORDINGLY...WHICH MEANT AN EXPANSION
OF THE CURRENT ADVISORY TO THE SOUTHEAST. LOOKING AT OBSERVATIONS
FROM YESTERDAY MORNING AND CLIMATOLOGY IT LOOKS LIKE THE VIS SHOULD
START COMING UP AFTER 9AM AND WILL END THE ADVISORY AT THAT TIME. A
SLOWLY INCREASING PRESSURE GRADIENT ACROSS SOUTHWESTERN ZONES
APPEARS TO BE LIMITING FOG POTENTIAL IN THIS AREA AS LATEST OBS FROM
HEZ/TVR/MCB/MLU INDICATE 5MI OR BETTER VIS. THE DENSE FOG ADVISORY
THAT WAS IN EFFECT FOR PORTIONS OF THIS AREA HAS BEEN CANCELLED AS A
RESULT. WILL KEEP A CLOSE ON THE FOG SITUATION THIS MORNING SO STAY
TUNED FOR UPDATES. WE MAY NEED TO EXPAND THE ADVISORY INTO THE
JACKSON METRO AT SOME POINT.
FOCUS THEN SHIFTS TO CLOUD COVER POTENTIAL THIS AFTERNOON AND HOW
THAT WILL IMPACT AFTERNOON HIGHS. LATEST RUC GUIDANCE IS NOT
CONFIDENT WE WILL SEE MUCH SUN THIS AFTERNOON AS LOW LEVEL MOISTURE
FIELDS REMAIN SATURATED FOR ALL BUT FAR EASTERN AREAS WHERE SOME
THINNING OF THE CLOUDS IS POSSIBLE. LATEST NAM/SREF INDICATE SOME
THINNING POSSIBLE NORTH OF I-20 THIS AFTERNOON REMAINING SOCKED IN
ELSEWHERE. OVERALL I LIKE WHAT THE RUC IS SHOWING AND HAVE
GENERALLY STUCK WITH CLOUDY SKIES TODAY FOR ALL AREAS...SHOWING A
FEW PEAKS OF SUN IN THE EAST THIS AFTERNOON. I DO HOWEVER THINK
THERE IS SOME POTENTIAL FOR A FEW BREAKS IN THE CLOUDS ACROSS THE
SOUTHWEST LATER ON AS THE LOW LEVEL FLOW PICKS UP IN RESPONSE TO A
PRESSURE GRADIENT THAT CONTINUES TO TIGHTEN. SO...WITH CLOUD COVER
REMAINING FAIRLY SOLID TODAY I HAVE GONE WITH THE LOWEST MEMBER OF
THE GFS MOS SUITE(MID TO UPPER 60S) FOR TEMPS TODAY...WHICH MIGHT
STILL BE TOO HIGH AS I THINK WE MIGHT STRUGGLE TO GET TO THE LOW 60S
ACROSS A BIG PORTION OF THE AREA.
TONIGHT INTO THURSDAY...A COLD FRONT WILL BE MOVING INTO SOUTH
CENTRAL AR LATE TONIGHT ATTENDANT TO A S/WV LIFTING ACROSS THE
CENTRAL PLAINS AND INTO THE GREAT LAKES REGION. LIGHT RAIN CHANCES
WILL BE ON THE INCREASE LATE TONIGHT/EARLY TOMORROW MORNING ACROSS
THE DELTA AS THIS FEATURE APPROACHES...WITH A FEW LIGHT NORTHWARD
MOVING SHOWERS AHEAD OF THE FRONT POSSIBLE ALONG/WEST OF THE MS
RIVER. THE FRONT WILL LIMP INTO MS LATE THURSDAY PUSHING SHOWER
CHANCES FURTHER SOUTHEAST AS IT ADVANCES. INSTABILITY IS RATHER WEAK
WITH THIS SYSTEM THANKS TO WARM MID/UPPER LEVEL TEMPS AND ASSOCIATED
WEAK LAPSE RATES. FORCING IS REAL WEAK AS WE REMAIN UNDER THE
INFLUENCE OF UPPER RIDGING ALOFT...ALL COMBINED I THINK THE
POTENTIAL FOR ANY STRONG TO SEVERE STORMS IS LOW THURSDAY. BUT...IF
THE INSTABILITY COMES IN A BIT HIGHER THAN FORECAST THERE COULD BE A
MARGINAL RISK OF 50MPH WIND GUSTS ACROSS THE FAR NORTHWEST EARLY TO
MID DAY THURSDAY. WILL GO AHEAD AND KEEP THAT MENTION IN THE HWO FOR
NOW. THE FRONT WILL STALL ACROSS CENTRAL PORTIONS OF THE FA THURSDAY
EVENING AS ANOTHER S/WV IN SOUTHWESTERLY FLOW LIFTS ACROSS THE
SOUTHERN PLAINS AND INTO THE MID MS VALLEY EARLY FRI. AS THIS BETTER
FORCING INTERACTS WITH THE FRONT WE COULD SEE A PERIOD OF MODERATE
RAIN THURSDAY NIGHT AS THE WAVE PASSES.
AS FOR TEMPS...LOWERED HIGHS FOR THURSDAY FOR MOST SITES AS CLOUD
COVER/RAIN POTENTIAL KEEP US FROM CLIMBING MUCH ABOVE
70...ESPECIALLY ACROSS THE DELTA WHERE WE PROBABLY WONT EVEN GET TO
70. OVERNIGHT LOWS SEEMED REASONABLE THIS PERIOD. /BK/
.LONG TERM...FRIDAY THROUGH WEDNESDAY...TWO PERIODS OF RAIN ARE
EXPECTED IN THE LONG TERM. THIS FIRST IS FRIDAY AND THE SECOND IS
MONDAY NIGHT. COME FRIDAY MORNING A NEARLY STATIONARY COLD FRONT IS
EXPECTED TO BE ACROSS THE SOUTHEAST PORTION OF OUR CWA. THE NAM IS A
LITTLE FARTHER NORTH...BUT MODEL CONSENSUS PLACES THE FRONT FROM
SOUTH OF NATCHEZ TO JUST NORTH OF MERIDIAN AT SUNRISE. THERE IS
EXPECTED TO BE PLENTY OF POST FRONTAL PRECIPITATION ACROSS OUR CWA
AS A CLOSED LOW OVER THE DESERT SOUTHWEST DRAWS PACIFIC MOISTURE
ACROSS THE SOUTHERN PLAINS AND OUR REGION ON SOUTHWEST WINDS ALOFT.
A COUPLE OF NORTHERN STREAM SHORTWAVES WILL MOVE ACROSS THE PLAINS
FRIDAY AND SATURDAY AND HELP A +1030MB SURFACE HIGH DROP SOUTH TO
THE ARKLATEX REGION BY SATURDAY AFTERNOON. AS THIS HIGH DROPS SOUTH
THE NEARLY STATIONARY FRONT WILL BE PUSHED SOUTH OF OUR CWA AND THE
ASSOCIATED RAIN WILL END. THE BULK OF THE RAIN SHOULD END FROM THE
NORTH FRIDAY EVENING BUT A SLIGHT CHANCE OF RAIN WILL CONTINUE IN
THE SOUTH INTO SATURDAY MORNING. GUIDANCE POPS CAME IN A LITTLE HIGH
AND TOO FAR NORTH. HAVE CUT GUIDANCE POPS ACROSS OUR CWA SATURDAY
THROUGH SUNDAY. TEMPERATURES WILL BE WELL ABOVE NORMAL FRIDAY SOUTH
OF THE FRONT AND NEAR NORMAL NORTH OF THE FRONT. COOLER...BUT NEAR
NORMAL TEMPERATURES ARE EXPECTED SATURDAY. THE SURFACE HIGH WILL
BECOME CENTERED OVER OUR CWA SUNDAY MORNING AND CONTINUE SHIFTING
EAST DURING THE DAY. INDUCED RIDGING ALOFT WILL STRENGTHEN OVERHEAD
DUE TO THE CLOSED LOW MOVING JUST SOUTH OF THE FOUR CORNERS REGION.
THIS RIDGING SURFACE AND ALOFT SHOULD ALLOW TEMPERATURES TO RECOVER
NICELY SUNDAY AND TOP OUT ABOVE NORMAL AGAIN. HIGHS WILL BE IN THE
LOW TO MID 60S. RIDGING SURFACE AND ALOFT WILL SHIFT EAST MONDAY AS
THE CLOSED LOW MOVES TO THE SOUTHERN PLAINS. WAA WILL STRENGTHEN
OVER OUR CWA AHEAD OF THE APPROACHING SYSTEM LEADING TO RAIN CHANCES
INCREASING FROM THE WEST MONDAY. THE GFS AND ECMWF DISAGREE ON THE
PROGRESSION OF THE LOW MONDAY AND TUESDAY. THE GFS MAINTAINS THE
CLOSED LOW AND LIFTS THE BOTH THE UPPER LEVEL LOW AND SURFACE LOW
SLOWLY ACROSS THE OZARKS MONDAY NIGHT AND OVER THE TENNESSEE VALLEY
BY TUESDAY MORNING. THE MORE PROGRESSIVE ECMWF OPENS UP THE CLOSED
LOW AND MOVES BOTH THE UPPER LEVEL TROUGH AND SURFACE LOW TO THE
UPPER GREAT LAKES REGION BY TUESDAY MORNING. BOTH SCENARIOS BRING A
COLD FRONT WITH WIDESPREAD RAIN TO OUR CWA MONDAY NIGHT INTO TUESDAY
BUT THE GFS PARAMETERS SUGGEST THE POSSIBILITY FOR SEVERE WEATHER
MONDAY NIGHT FOR OUR CWA. WITH SUCH MODEL DISCREPANCIES WL HOLD OFF
INTRODUCING MENTION OF SEVERE WEATHER POTENTIAL IN THE HWO BUT LOOK
TO FUTURE RUNS FOR SOME CONTINUITY AND A MORE LIKELY CONSENSUS.
WEDNESDAY CURRENTLY LOOKS TO BE COOLER AND DRY FOR OUR REGION. /22/
&&
.AVIATION...WDSPRD IFR CIG ARE PLAGUING THE REGION THIS
MORNING...ACCOMPANIED BY VRBL VSBYS RANGING FROM 1/4 TO 6SM. CIG
WILL LIKELY VARY BETWEEN 100 AND 800 FT UNTIL 17Z AT MOST SITES.
CLIMATOLOGY SUGGESTS CIG WILL TREND MVFR BY 18-19Z ALTHOUGH
CONFIDENCE IS LOW IN THIS BEING WDSPRD AS WE STRUGGLED TO LIFT MVFR
YESTERDAY. BEST CHANCE OF SEEING ANY SCT LOW CLOUDS WILL BE AT
MEI/HEZ THIS AFTN BUT THIS WILL PROB BE SHORT IF IT OCCURS AS IFR
CIG RETURN THIS EVENING. VIS WILL TREND MVFR 13-14Z BUT A TREND BACK
TOWARD IFR VSBY IS LIKELY TONIGHT. SFC WINDS WILL BE OUT OF THE SE
TODAY BECMG SRLY TONIGHT. /BK/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 68 59 72 57 / 0 13 48 82
MERIDIAN 70 54 74 59 / 0 10 37 74
VICKSBURG 69 60 71 52 / 1 22 69 84
HATTIESBURG 69 57 76 58 / 4 10 25 49
NATCHEZ 70 63 74 55 / 1 16 63 83
GREENVILLE 66 59 67 48 / 3 43 78 81
GREENWOOD 67 62 69 51 / 1 31 75 80
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ018-019-
025>039-044>046-050>052-056>058-065-066-073-074.
LA...NONE.
AR...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ARZ074-075.
&&
$$
BK/22/BK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
934 AM EST WED DEC 14 2011
.SYNOPSIS...
A WEAK WARM FRONT LIFTS TO OUR NORTH TODAY. A COLD FRONT CROSSES
THURSDAY EVENING. DEEPER MOISTURE MAY KINK BACK NORTH AND BRUSH
AREA ON FRIDAY. DRY WITH HIGH PRESSURE FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
BASED ON LATEST RADAR TRENDS AND THE HRRR MODEL...HAVE UPDATED
POPS. MEASURABLE PRECIPITATION WAS MUCH FARTHER SOUTH THAN
PREVIOUSLY EXPECTED. HOWEVER...HRRR MODEL INDICATES THE AREA OF
SHOWERS SHOULD PUSH NORTH OF AREA THIS AFTERNOON.
WILL LIKELY TWEAK SKY GRIDS DOWNWARD AS VISIBLE IMAGERY SHOWS
ABUNDANT SUNSHINE TO OUR SOUTHWEST. CURRENT TEMPS ARE COOLER THAN
FORECASTED...SO WILL TWEAK DOWNWARD DOWNWARD. HOWEVER...STILL FEEL
FORECASTED HIGHS ARE REACHABLE...AND WILL NOT CHANGE.
PREVIOUS DISCUSSION...
ILL-DEFINED WARM FRONT SOMEWHERE NEAR THE JUNCTION OF THE
MISSISSIPPI AND OHIO RIVERS EARLY THIS MORNING MOVES NE THROUGH
THE FORECAST AREA THIS AFTERNOON. WARM ADVECTION RAIN OUT AHEAD OF
THE FRONT ENCOMPASSING MUCH OF THE OHIO VALLEY NORTH OF THE RIVER
EARLY THIS MORNING WILL STAY MAINLY ON THAT SIDE OF THE RIVER AS
IT IMPACTS OUR SE OHO COUNTIES...BLEEDING INTO NORTHERN WV BEFORE
LIFTING N THIS AFTERNOON.
AREA WILL THEN BE ENTIRELY IN WARM SECTOR BY LATE TODAY AND REMAIN
SO THROUGH TONIGHT. TIGHTENING GRADIENT SPELLS INCREASING WINDS
TONIGHT ESPECIALLY ON THE RIDGES. MODELS IN GOOD AGREEMENT ON
TIMING OF COLD FRONT APPROACHING FROM THE W...WITH SHOWERS AHEAD OF
THE FRONT REACHING NEAR THE OHIO RIVER BY 12Z THU.
HIGHS TODAY LOOKED GOOD...CLOSE TO ADJMETBC.,,WITH LITTLE CHANGE
NEEDED. BLENDED IN ADJMET FOR LOWS TONIGHT WHICH ALSO ENTAILED ONLY
SMALL CHANGES. DID WARM THE RIDGE AND HILLTOPS A BIT OVERNIGHT AS
SW WINDS INCREASE THERE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
NO MAJOR CHANGES NEEDED TO THE SHORT TERM PERIOD. COLD FRONT WILL
MOVE INTO THE CWA AT THE BEGINNING OF THE PERIOD...SPREADING SHOWERS
FROM WEST TO EAST WITH IT. THIS IS A RATHER MOIST SYSTEM...WITH PW
VALUES EXPECTED TO CLIMB INTO THE 1.1 TO 1.3 RANGE...AIDED BY 50+KT
LLJ. STILL NOT EXPECTING ANY WATER ISSUES WITH THIS SYSTEM HOWEVER
DUE TO ITS OVERALL PROGRESSIVE NATURE...AND STILL FIGURING GENERALLY
ABOUT 0.5 TO 0.75 INCHES QPF. WITH THE GOOD SOUTHERLY FLOW EXPECTED
OUT AHEAD OF THE APPROACHING COLD FRONT...MAX TEMPERATURES ON
THURSDAY ARE EXPECTED TO CLIMB WELL ABOVE NORMAL...WITH ALL OF THE
CWA EXPECTED TO CLIMB INTO THE 50S TO LOWER 60S. WITH THE WARM AIR
IN PLACE...SHOULD SEE A MAINLY RAIN EVENT...EXCEPT FOR THE
POSSIBILITY OF SOME LIGHT RAIN/SNOW OR SNOW SHOWERS IN THE NORTHERN
MOUNTAIN ZONES FRIDAY MORNING BEHIND THE FRONT. HOWEVER...THIS WILL
DEPEND ON A VARIETY OF FACTORS INCLUDING AMOUNT OF ATMOSPHERIC
MOISTURE REMAINING AND HOW MUCH COLD AIR IS ACTUALLY IN PLACE.
REGARDLESS...ACCUMULATIONS DO NOT LOOK FAVORABLE.
FRONTAL BOUNDARY WILL EXIT TO THE SOUTH ON FRIDAY WITH ANOTHER WAVE
RIDING ALONG THE FRONT FROM THE SOUTH FRIDAY THROUGH FRIDAY NIGHT.
THIS WILL MAINLY AFFECT THE SOUTHERN AND EASTERN ZONES. RECENT RUN
OF THE NAM APPEARS TO KEEP MOISTURE ASSOCIATED WITH THIS FEATURE
FARTHER TO THE SOUTH THAN THE GFS OR ECMWF...AND IF THIS SCENARIO
TURNS OUT...WILL MAINLY AFFECT SOUTHWEST VA AND EXTREME SOUTHERN
COAL FIELDS. GFS AND ECMWF OVERSPREAD MOISTURE FARTHER NORTH INTO
THE AREA...AS FAR NORTH AS CRW. FOR NOW...KEPT ONLY CHANCE TO SLIGHT
CHANCE POPS TO THE NORTH...WITH LIKELY OVER SOUTHWEST VA AND
SOUTHERN COAL FIELDS DUE TO UNCERTAINTY. IF MOISTURE IS ABLE TO
SPREAD FARTHER NORTH...AND DEPENDING ON THE EXACT TRACK OF THE
WAVE...COULD SEE SOME LIGHT SNOW IN THE NORTHERN MOUNTAIN ZONES
FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SFC HIGH BUILDS IN OVER THE WEEKEND TO PROVIDE FOR DRY AND
SEASONABLE CONDITIONS...ALBEIT ON THE COLD SIDE FOR LOW TEMPS. NEXT
SYS SLATED FOR MON NIGHT AND TUES AS SW LOW EJECTS NE TOWARD THE
AREA...INCREASING THE CHANCES FOR RAIN.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
WARM FRONT WILL BE THE MAIN WEATHER MAKER THIS PERIOD...WITH ITS
PASSAGE DURING THE DAY ON WED.
PATCHY MVFR STRATOCU MAINLY NEAR OHIO RIVER AS THE WARM FRONT
APPROACHES. LIGHT RAIN ASSOCIATED WITH THE FRONT AFFECTING EASTERN
OHIO INTO NORTHERN WV THIS MORNING WITH NO APPRECIABLE VSBY
RESTRICTIONS. THE RAIN WHICH WILL MOVE N OF THE AREA THROUGH LATE
MORNING.
CIGS WILL LIFT FROM S TO N...FOLLOWED BY CLEARING...AS THE FRONT
MOVES N THROUGH THE AREA THIS AFTERNOON. EXPECT VFR AREA WIDE BY
THIS EVENING IN THE WARM SECTOR. SHOWERS ASSOCIATED WITH A COLD
FRONT APPROACHING FROM THE W WILL REACH THE OHIO RIVER AROUND 12Z
THU. MVFR AND WORSE CONDITIONS SHOULD HOLD OFF UNTIL AFTER 12Z.
LIGHT AND VARIABLE WINDS THIS MORNING WILL STRENGTHEN A BIT FROM THE
S DURING THE DAY TODAY...AND MAY NOT DIMINISH MUCH TONIGHT. WINDS
TONIGHT WILL ACTUALLY STRENGTHEN ON THE RIDGES...AS LIGHT W WINDS
ALOFT THIS MORNING BACK TO SW BY WED EVENING AND BECOME STRONG THIS
EVENING AND REMAIN STRONG OVERNIGHT. WIND SHEAR TOWARD THU MORNING
COULD APPROACH LLWS CRITERIA OF 20KTS/200FT WITHIN 2KFT AGL.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF THE MVFR CIGS THIS MORNING
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY M H H H H H H H H H H H
HTS CONSISTENCY M H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY H H M L H H H H H H H H
AFTER 12Z THURSDAY...
IFR POSSIBLE IN RAIN SHOWERS WITH COLD FRONT THURSDAY INTO THURSDAY
NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...JSH/TRM
SHORT TERM...SL
LONG TERM...30
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
331 PM CST WED DEC 14 2011
.DISCUSSION...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS NORTH
TEXAS THIS AFTERNOON AS A PACIFIC COLD FRONT MOVES EAST. THE UPPER
LEVEL SYSTEM RESPONSIBLE FOR DEEP LAYER ASCENT IS SHEARING OUT
ACROSS THE SOUTHERN PLAINS AND WILL MOVE NORTHEAST THIS EVENING
ALLOWING THE FRONTAL BOUNDARY TO SLOW DOWN AS IT MOVES EAST.
LATEST RUC SOUNDINGS AND LOCALLY DERIVED CONVECTIVE PARAMETERS
INDICATE THAT 700MB WARM NOSE HAS MOSTLY ERODED WITH ONLY WEAK
INHIBITION PRESENT IN VICINITY OF THE FRONT. ANYWHERE FROM
500-700J/KG OF INSTABILITY REMAINS PRESENT AND WILL SUPPORT
THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING INTO TONIGHT.
OVERALL SEVERE WEATHER THREAT IS LOW BUT SOME HAIL WILL REMAIN
POSSIBLE. FRONT WILL DRIFT SOUTH AND EAST LATER TONIGHT WITH
PRECIP TAPERING FROM WEST TO EAST.
ALTHOUGH SURFACE FRONT WILL BE SOUTH OF THE AREA ON THURSDAY AMPLE
MOISTURE WILL RIDE ATOP THE SHALLOW COOLER AIR. REMNANTS OF THE
UPPER LOW OVER THE SOUTHWEST IS EXPECTED TO EJECT NORTHEAST DURING
THE DAY TOMORROW. THIS SYSTEM SHOULD PROVIDE SUFFICIENT FORCING TO
LIFT MOISTURE IN THE 850-700MB LAYER. ELEVATED INSTABILITY WILL BE
WEAK ALTHOUGH IT SHOULD BE SUFFICIENT FOR SHOWERY TYPE PRECIP TO
DEVELOP EVEN THOUGH THE NEAR SURFACE LAYER WILL BE DRY. MODEL
GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION AND HAVE RAISED
POPS FOR THU/THU NIGHT ACROSS NORTH TEXAS.
FRIDAY AND SATURDAY STILL LOOK LIKE THE QUIETEST DAYS THROUGH THE
NEXT SEVERAL WITH MOST AREAS STAYING DRY. THE NEXT STRONG SYSTEM
IS EXPECTED TO MOVE OUT OF THE SOUTHWEST US BY SUNDAY. MOISTURE
WILL SURGE NORTHWARD AHEAD OF THIS UPPER LOW...WHICH IS FORECAST
TO REMAIN CLOSED AS IT MOVES ACROSS NORTH TEXAS. THIS SYSTEM
CONTINUES TO LOOK MORE POTENT AND AGAIN WE MAY SEE SOME
SIGNIFICANT RAINFALL AS IT MOVES THROUGH. WILL HAVE TO MONITOR FOR
SEVERE WEATHER POTENTIAL AS WE GET CLOSER TO THE EVENT.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 54 56 40 54 38 / 60 50 70 10 10
WACO, TX 58 58 42 53 42 / 90 60 70 20 20
PARIS, TX 55 57 39 51 37 / 90 40 70 20 10
DENTON, TX 51 54 38 51 33 / 40 40 70 10 10
MCKINNEY, TX 54 56 41 52 36 / 70 40 70 20 10
DALLAS, TX 55 58 41 54 41 / 70 50 70 20 10
TERRELL, TX 57 59 42 52 40 / 90 50 70 20 10
CORSICANA, TX 59 62 45 54 42 / 90 60 70 30 20
TEMPLE, TX 59 59 42 53 43 / 80 70 70 20 20
MINERAL WELLS, TX 48 52 37 50 35 / 10 40 60 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1119 AM CST WED DEC 14 2011
.AVIATION...
IFR CONDITIONS REMAIN FAIRLY EXTENSIVE ACROSS NORTH TEXAS LATE
THIS MORNING. LOCAL AIRPORTS ALONG THE I 35 CORRIDOR CONTINUE TO
REPORT CIGS AT OR BELOW 010 AND FEEL THIS WILL CONTINUE THROUGH
THE MID AFTERNOON HOURS. CONDITIONS SHOULD THEN IMPROVE SOME AS
TEMPERATURES APPROACH 70 AND WINDS BEGIN TO VEER AHEAD OF THE
PACIFIC FRONT TO THE WEST.
INSTABILITY SHOULD NOT BE OVERLY IMPRESSIVE AS INITIAL SHORTWAVE
MOVES ACROSS THE AREA THIS AFTERNOON. HOWEVER...CONVERGENCE ALONG THE
SURFACE BOUNDARY COMBINED WITH SB CAPES BETWEEN 500 AND 1000 J/KG
SHOULD BE SUFFICIENT FOR THE DEVELOPMENT OF THUNDERSTORMS. WILL
TIME THE ONSET OF OCCASIONAL TS IN THE METROPLEX SIMILAR TO THE
12Z LOCAL WRF SOLUTION...WHICH WOULD BEGIN AROUND 22Z. WINDS WILL
VEER TO THE SW BEHIND THE LEADING EDGE OF THE HEAVIER PRECIP. MAIN
PUSH OF COOLER DRIER AIR AT THE SURFACE WOULD BE LATE TONIGHT AND
WILL CONTINUE WITH THE NORTHWEST WINDS PRIOR TO SUNRISE TOMORROW.
IT LOOKS LIKE THE FRONT MAY HANG UP JUST SOUTH OF THE FORECAST
AREA TOMORROW. OVERRUNNING PRECIP WILL THEN BECOME A POSSIBILITY
BY TOMORROW AFTERNOON AS THE NEXT SHORTWAVE PROPAGATES EASTWARD
INTO THE AREA.
30
&&
.UPDATE...
ELONGATED TROF AXIS PERSISTS FROM THE CENTRAL PLAINS BACK INTO THE
SOUTHWEST US WITH ONE SIGNIFICANT PIECE OF ENERGY EJECTING
NORTHEAST THIS MORNING. THIS S/W WILL HELP PUSH A PACIFIC FRONT
THROUGH THE REGION THIS AFTERNOON. REGIONAL RADAR IMAGERY ALREADY
SHOWS A BROKEN LINE OF PRIMARILY SHOWERS DEVELOPING TO THE
NORTHWEST OF THE CWA. THIS IS EXPECTED TO GRADUALLY FILL IN AND
MOVE EAST THROUGH THE DAY AS THE FRONT GAINS MOMENTUM. ALL OF THE
HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THAT A LINE OF
CONVECTION WILL MOVE THROUGH NORTH TEXAS THROUGH THIS AFTERNOON
ALONG THE FRONT...HOWEVER THERE IS SOME DISCREPANCY AS TO HOW
INTENSE IT WILL BE. LATEST NAM IS MOST AGGRESSIVE WITH INSTABILITY
AND STILL INDICATES AN AXIS OF 700-1000J/KG OF OF CAPE ACROSS
NORTH TEXAS AND WEAKENS THE CAPPING AROUND 700MB. RUC SOUNDINGS
ARE NOT SO QUICK TO ERODE THE CAPPING AND INDICATE THAT DEEP
CONVECTION WILL BE HARD TO COME BY. GIVEN THE EXTENSIVE CLOUD
COVER AND ONGOING DRIZZLE TEND TO THINK THE LESS AGGRESSIVE RUC
MAY HAVE A BETTER HANDLE ON THINGS. WILL CONTINUE TO MENTION
THUNDERSTORMS THROUGH THE AFTERNOON...BUT OVERALL SEVERE WEATHER
THREAT MAY BE CONFINED TO A FEW ISOLATED CELLS. THIS IS ONE OF
THOSE SITUATIONS THOUGH WHERE A LITTLE EXTRA HEATING OR SLIGHTLY
MORE WEAKENING OF THE CAP COULD RESULT IN MORE WIDESPREAD SEVERE
CONVECTION SO IT IS WORTH WATCHING THROUGH THE AFTERNOON. ONLY
SOME MINOR TWEAKS TO POP/WEATHER WORDING THROUGH THE AFTERNOON
OTHERWISE NO MAJOR CHANGES TO THE CURRENT FORECAST.
DUNN
&&
.PREV DISCUSSION... /ISSUED 344 AM CST WED DEC 14 2011/
MOIST ISENTROPIC ASCENT WILL CONTINUE TODAY AS THE LOW LEVEL JET
REMAINS STRONG AND CONTINUES TO TRANSPORT RICH MOISTURE INTO THE
REGION. SOME INSTABILITY WILL WORK INTO THE WESTERN COUNTIES THIS
MORNING AND THEN SPREAD EASTWARD THIS AFTERNOON AND EVENING. THERE
IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH HAIL AND DAMAGING
WINDS DUE TO AN APPROACHING SHORTWAVE...A 90-100 KNOT JET ALOFT AND
400-1000 J/KG OF CAPE. BEST TIMING FOR SEVERE WILL BE MID/LATE
AFTERNOON OVER THE WESTERN HALF AND THIS EVENING FOR THE EASTERN
HALF. A COLD FRONT WILL SWING THROUGH NORTH TEXAS LATER TONIGHT
AND BRING COOLER NORTHERLY WINDS BACK TO THE REGION.
A STRONG SHORTWAVE WILL KICK OUT OF THE PERSISTENT SOUTHERN
CALIFORNIA UPPER LOW AND PASS OVER THE REGION THURSDAY EVENING.
HAVE HELD ONTO LOW POPS THURSDAY AND THURSDAY NIGHT AS MID LEVEL
LIFT MOVES ACROSS THE REGION. AS THE SHORTWAVE MIGRATES EAST OF THE
REGION...RAIN CHANCES WILL END FOR MOST OF THE CWA BUT LINGER
OVER THE SOUTHERN COUNTIES THROUGH FRIDAY. THERE WILL BE A BRIEF
LULL IN RAIN CHANCES ON SATURDAY...BUT THEY RETURN TO THE WESTERN
COUNTIES SATURDAY NIGHT AS THE MAIN UPPER LOW OVER SOUTHERN
CALIFORNIA BEGINS TO MOVE EAST. AS THE UPPER SYSTEM NEARS TEXAS...
RAIN CHANCES WILL INCREASE WEST TO EAST SUNDAY THROUGH
MONDAY...AND HAVE INCLUDED THUNDERSTORM POTENTIAL FOR MONDAY
MORNING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
EVENING.
TEMPERATURES FOR THE MOST PART WILL BE SEASONAL WITH ABOVE NORMAL
CONDITIONS AHEAD OF TONIGHT/S COLD FRONT AND MONDAY/S COLD FRONT.
75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 72 50 58 39 53 / 100 50 30 40 10
WACO, TX 74 50 57 43 54 / 80 50 40 60 10
PARIS, TX 72 53 64 42 53 / 80 70 30 50 10
DENTON, TX 69 46 58 36 51 / 100 40 30 30 10
MCKINNEY, TX 69 49 60 40 52 / 100 50 30 40 10
DALLAS, TX 71 51 58 40 54 / 100 50 40 40 10
TERRELL, TX 70 53 61 42 55 / 90 60 40 50 10
CORSICANA, TX 72 55 59 45 55 / 70 60 40 60 10
TEMPLE, TX 73 53 58 43 56 / 60 50 50 60 20
MINERAL WELLS, TX 71 43 55 34 51 / 100 20 30 30 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
941 AM CST WED DEC 14 2011
.UPDATE...
ELONGATED TROF AXIS PERSISTS FROM THE CENTRAL PLAINS BACK INTO THE
SOUTHWEST US WITH ONE SIGNIFICANT PIECE OF ENERGY EJECTING
NORTHEAST THIS MORNING. THIS S/W WILL HELP PUSH A PACIFIC FRONT
THROUGH THE REGION THIS AFTERNOON. REGIONAL RADAR IMAGERY ALREADY
SHOWS A BROKEN LINE OF PRIMARILY SHOWERS DEVELOPING TO THE
NORTHWEST OF THE CWA. THIS IS EXPECTED TO GRADUALLY FILL IN AND
MOVE EAST THROUGH THE DAY AS THE FRONT GAINS MOMENTUM. ALL OF THE
HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THAT A LINE OF
CONVECTION WILL MOVE THROUGH NORTH TEXAS THROUGH THIS AFTERNOON
ALONG THE FRONT...HOWEVER THERE IS SOME DISCREPANCY AS TO HOW
INTENSE IT WILL BE. LATEST NAM IS MOST AGGRESSIVE WITH INSTABILITY
AND STILL INDICATES AN AXIS OF 700-1000J/KG OF OF CAPE ACROSS
NORTH TEXAS AND WEAKENS THE CAPPING AROUND 700MB. RUC SOUNDINGS
ARE NOT SO QUICK TO ERODE THE CAPPING AND INDICATE THAT DEEP
CONVECTION WILL BE HARD TO COME BY. GIVEN THE EXTENSIVE CLOUD
COVER AND ONGOING DRIZZLE TEND TO THINK THE LESS AGGRESSIVE RUC
MAY HAVE A BETTER HANDLE ON THINGS. WILL CONTINUE TO MENTION
THUNDERSTORMS THROUGH THE AFTERNOON...BUT OVERALL SEVERE WEATHER
THREAT MAY BE CONFINED TO A FEW ISOLATED CELLS. THIS IS ONE OF
THOSE SITUATIONS THOUGH WHERE A LITTLE EXTRA HEATING OR SLIGHTLY
MORE WEAKENING OF THE CAP COULD RESULT IN MORE WIDESPREAD SEVERE
CONVECTION SO IT IS WORTH WATCHING THROUGH THE AFTERNOON. ONLY
SOME MINOR TWEAKS TO POP/WEATHER WORDING THROUGH THE AFTERNOON
OTHERWISE NO MAJOR CHANGES TO THE CURRENT FORECAST.
DUNN
&&
.AVIATION...
.CONCERNS...
MANY CHALLENGES WITH CIGS/VSBY AND TIMING OF SURFACE TROUGH AND
ASSOCIATED TSRA/CB THIS AFTERNOON. COLD FRONT TIMING A LITTLE
TRICKY THURSDAY MORNING.
CURRENT REGIONAL RADAR AND AREA WX OBSERVATIONS INDICATE LIFT IS
INCREASING ACROSS NORTHWEST TX/WRN OK THIS MORNING WITH SHRA/-RA
BECOMING WIDESPREAD FROM KSPS TO KCDS/KOKC. GUSTY SE WINDS 13-23KTS
ARE ASSISTING IN THE PRODUCTION OF SPOTTY -RA/-DZ AND IFR STRATUS.
WHERE HEAVIER DZ OCCURS...CIGS ARE FALLING INTO LIFR CATEGORY
BETWEEN 003-005 KFT. WILL HAVE A TEMPO GROUP FOR THIS POSSIBILITY
THROUGH MID MORNING AT ALL TERMINALS.
INCREASING LIFT THIS AFTERNOON WILL COMBINE WITH LOW LEVEL WARMING
/GUSTY SOUTH WINDS TO LIFT CIGS BACK INTO THE MVFR...OR POSSIBLY A
LOW VFR CATEGORY BY 21Z. BEST GUESS WINDOW FOR TSRA AT DFW
TERMINALS WILL BE 20-22Z AND 22Z-00Z AT WACO. -SHRA/-RA LIKELY
WILL LINGER THROUGH MID EVENING.
WINDS GRADUALLY SHIFT SOUTHWEST AND DECREASE TO 5-10 KTS AFTER
PASSAGE OF SURFACE TROUGH LATE THIS AFTERNOON...THEN BECOME NORTHWEST
AROUND 10 KTS EARLY THURSDAY MORNING WITH THE COLD FRONT MOVING
THROUGH THE AREA.
05/
&&
.PREV DISCUSSION... /ISSUED 344 AM CST WED DEC 14 2011/
MOIST ISENTROPIC ASCENT WILL CONTINUE TODAY AS THE LOW LEVEL JET
REMAINS STRONG AND CONTINUES TO TRANSPORT RICH MOISTURE INTO THE
REGION. SOME INSTABILITY WILL WORK INTO THE WESTERN COUNTIES THIS
MORNING AND THEN SPREAD EASTWARD THIS AFTERNOON AND EVENING. THERE
IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH HAIL AND DAMAGING
WINDS DUE TO AN APPROACHING SHORTWAVE...A 90-100 KNOT JET ALOFT AND
400-1000 J/KG OF CAPE. BEST TIMING FOR SEVERE WILL BE MID/LATE
AFTERNOON OVER THE WESTERN HALF AND THIS EVENING FOR THE EASTERN
HALF. A COLD FRONT WILL SWING THROUGH NORTH TEXAS LATER TONIGHT
AND BRING COOLER NORTHERLY WINDS BACK TO THE REGION.
A STRONG SHORTWAVE WILL KICK OUT OF THE PERSISTENT SOUTHERN
CALIFORNIA UPPER LOW AND PASS OVER THE REGION THURSDAY EVENING.
HAVE HELD ONTO LOW POPS THURSDAY AND THURSDAY NIGHT AS MID LEVEL
LIFT MOVES ACROSS THE REGION. AS THE SHORTWAVE MIGRATES EAST OF THE
REGION...RAIN CHANCES WILL END FOR MOST OF THE CWA BUT LINGER
OVER THE SOUTHERN COUNTIES THROUGH FRIDAY. THERE WILL BE A BRIEF
LULL IN RAIN CHANCES ON SATURDAY...BUT THEY RETURN TO THE WESTERN
COUNTIES SATURDAY NIGHT AS THE MAIN UPPER LOW OVER SOUTHERN
CALIFORNIA BEGINS TO MOVE EAST. AS THE UPPER SYSTEM NEARS TEXAS...
RAIN CHANCES WILL INCREASE WEST TO EAST SUNDAY THROUGH
MONDAY...AND HAVE INCLUDED THUNDERSTORM POTENTIAL FOR MONDAY
MORNING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
EVENING.
TEMPERATURES FOR THE MOST PART WILL BE SEASONAL WITH ABOVE NORMAL
CONDITIONS AHEAD OF TONIGHT/S COLD FRONT AND MONDAY/S COLD FRONT.
75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 72 50 58 39 53 / 100 50 30 40 10
WACO, TX 74 50 57 43 54 / 80 50 40 60 10
PARIS, TX 72 53 64 42 53 / 80 70 30 50 10
DENTON, TX 69 46 58 36 51 / 100 40 30 30 10
MCKINNEY, TX 69 49 60 40 52 / 100 50 30 40 10
DALLAS, TX 71 51 58 40 54 / 100 50 40 40 10
TERRELL, TX 70 53 61 42 55 / 90 60 40 50 10
CORSICANA, TX 72 55 59 45 55 / 70 60 40 60 10
TEMPLE, TX 73 53 58 43 56 / 60 50 50 60 20
MINERAL WELLS, TX 71 43 55 34 51 / 100 20 30 30 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
316 PM CST WED DEC 14 2011
.TONIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SHEARED VORT MAX STRETCHING FROM NORTHEAST NEW MEXICO TO EASTERN
NEBRASKA APPARENT IN 1945Z WATER VAPOR IMAGERY AND RUC ANALYSIS.
RAIN SPREAD BACK INTO SOUTHERN WI EARLY THIS AFTERNOON...SUPPORTED
BY 500MB VORT MAX PUSHING INTO SOUTH CENTRAL WI...WARM AIR ADVECTION
AND CONTINUED ISENTROPIC LIFT. OMEGA VALUES WILL ALSO INCREASE
BETWEEN NOW AND 7 PM AS WELL...PER RUC AND NAM MODEL SNDGS.
REGIONAL RADAR NOW ROUGHLY SHOWING DRY SLOT MOVING INTO CENTRAL
IOWA...CORRESPONDING TO THE CENTER OF SFC LOW PRESSURE. OBS STILL
SHOWING DRIZZLE IN THE VICINITY. SFC LOW WILL MOVE INTO NORTHEAST
IOWA AROUND 00Z...AND CLIP THE NORTHWEST FORECAST AREA AS IT MOVES
ACROSS CENTRAL WI AT 03Z. THE SFC TROUGH/COLD FRONT WILL THEN TREK
ACROSS SOUTHEAST WI FROM 05Z TO 09Z...USHERING IN COLDER AND DRIER
AIR...AS THE SFC LOW MOVES INTO EASTERN UPPER MICHIGAN. LOW LEVELS
WILL REMAIN MOIST BEHIND THE FRONT...BUT DRY OUT ALOFT...THUS
CAUSING DRIZZLE BEHIND THE DEPARTING LOW THROUGH AROUND 15Z/9AM THU
MORNING.
THE BAGGY PRESSURE GRADIENT OVER THE WESTERN FORECAST AREA WILL
ALLOW FOR AREAS OF DENSE FOG THROUGH LATE EVENING UNTIL THE COLD
FRONT COMES THROUGH AND THE WINDS INCREASE. DENSE FOG ADVY POSTED.
TEMPERATURES WILL KEEP RISING THROUGH THE EVENING...REACHING OUR
DAILY HIGH IN THE UPPER 40S/LOWER 50S AROUND MIDNIGHT. TEMPS WILL
GRADUALLY FALL THROUGH THE DAY THU...DROPPING DOWN TO AROUND
FREEZING FROM NW TO SE DURING THE AFTERNOON HOURS.
PRECIP IS EXPECTED TO END BY LATE THU MORNING...AND CLOUDS SHOULD
BREAK UP DURING THE AFTERNOON HOURS...BECOMING PARTLY CLOUDY BY
EVENING.
.THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE IS HIGH.
SKIES CONTINUE TO CLEAR OUT EARLY THURSDAY EVENING AS THE LOW
PULLS AWAY AND HIGH PRESSURE BUILDS IN. THINGS COOL DOWN...BUT
REMAIN AT OR SLIGHTLY ABOVE NORMAL.
.FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS MEDIUM.
A COUPLE OF WEAK MID LEVEL SHORT WAVES COME THROUGH THE FAST
NORTHWEST FLOW FRIDAY NIGHT AND AGAIN SATURDAY AFTERNOON. MOISTURE
BEGINS TO RETURN AND THERE IS SOME INDICATION WE COULD GET ENOUGH
COLUMN SATURATION TO SQUEEZE OUT A FEW FLAKES OF SNOW. HAVE
INTRODUCED A SLIGHT CHANCE OF LIGHT SNOW...BUT LITTLE OR NO
ACCUMULATION IS EXPECTED. THE GFS AND THE NAM ARE HINTING AT SOME
VERY LIGHT QPF THROUGH THIS PERIOD.
.SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
QUIET CONDITIONS EXPECTED THIS PERIOD AS WEAK RIDGING MOVES
THROUGH. TEMPS REMAIN AT OR ABOVE NORMAL.
.SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE IS LOW.
THERE IS MAJOR MODEL UNCERTAINTY FOR EARLY NEXT WEEK. AT ISSUE IS
WHETHER WE/LL SEE A LOW MOVE UP INTO THE GREAT LAKES AND GIVE US
RAIN...OR STAY WELL TO THE SOUTH AND KEEP US DRY...OR TAKE A
COMPROMISE OF THE TWO AND POSSIBLY GIVE US SOME ACCUMULATING SNOW.
THE GFS HAS MAINTAINED IT/S SOUTHERN DRY SOLUTION FOR US...THE
CANADIAN LOOKS FAIRLY WARM/RAINY WITH A LOW MOVING INTO THE
CENTRAL GREAT LAKES...WHILE THE ECMWF IS A COMPROMISER TAKING A
LOW THROUGH CENTRAL ILLINOIS/INDIANA. THE ECMWF WOULD BE COOLER
DURING THE PRECIP AND THIS COULD RESULT IN SOME ACCUMULATING
SNOW...NOTHING MAJOR AT THIS POINT. THE MODELS ARE HAVING A VERY
DIFFICULT TIME PHASING ENERGY FROM THE SOUTHERN AND NORTHERN
STREAMS. HAVE KEPT POPS IN THE CHC CATEGORY UNTIL WE GET A LITTLE
MORE CONSENSUS.
&&
.AVIATION/00Z TAFS/...SURFACE LOW PRESSURE WILL TRACK ACROSS
NORTHEAST IOWA...CENTRAL WI AND EASTERN UPPER MICHIGAN THROUGH
TONIGHT. BAGGY PRESSURE GRADIENT BENEATH THE SFC LOW WILL COVER
SOUTH CENTRAL WI...ALLOWING AREAS OF DENSE FOG TO DEVELOP/PERSIST
THROUGH THE EVENING.
RAIN ASSOCIATED WITH THE 500MB SHORTWAVE...850MB WARM AIR
ADVECTION...AND STRONG OMEGA WILL DIMINISH AS THE SFC LOW COMES
OVERHEAD...AS THE DRY SLOT HITS THE REGION.
COLD FRONTAL PASSAGE WILL OCCUR BETWEEN 05Z AND 08Z TONIGHT. STRONG
COLD ADVECTION THU AM WILL IMPROVE CONDITIONS BY RAISING THE
CEILINGS AND IMPROVING VISIBILITY. WIND GUSTS TO 30 KNOTS
POSSIBLE...ESPECIALLY AT MKE. CLOUDS SHOULD SCATTER OUT DURING THU
AFTERNOON.
&&
.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 6 PM TNT THROUGH
9 PM THU EVENING. BREEZY SSWLY WINDS AND HIGH WAVES WILL DEVELOP
THIS EVENING WITH A COLD FRONTAL PASSAGE EXPECTED TO SHIFT THE WINDS
TO THE WEST BY 09Z TNT. STRONG COLD ADVECTION WILL COMBINE WITH THE
RELATIVELY MILD LAKE MI WATER TEMPS TO PRODUCE UNSTABLE CONDITIONS
IN THE LOW LEVEL ATMOSPHERE. THIS WILL ENHANCE THE ALREADY MODERATE
WIND FIELD WITH WIND GUSTS EXPECTED TO REACH 30 KTS. THE WAVES WILL
DECREASE AFTER COLD FROPA DUE TO THE WLY COMPONENT OF THE WIND AND
THEREFORE LESS FETCH TO GENERATE WAVES. HOWEVER...HIGH WAVES WILL
STILL OCCUR OVER THE OPEN WATERS OF LAKE MI. THE WINDS WILL SUBSIDE
BY LATE THU EVENING AS A LARGE HIGH PRESSURE AREA APPROACHES FROM
THE WEST.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR WIZ046-047-056-
057-062-063-067-068.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THURSDAY FOR LMZ643>646.
&&
$$
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1152 PM CST THU DEC 15 2011
.AVIATION...
CLEAR VFR CONDITIONS HAVE RETURNED TO THE AREA ALONG WITH MUCH
COLDER AND DRIER AIR MOVING IN ON THE HEELS OF LAST NIGHTS COLD
FRONT. A WEAK SHORTWAVE TO MOVE FROM MINNESOTA TO NORTHERN
ILLINOIS FRIDAY NIGHT WHICH SHOULD BRING VFR CLOUDS TO THE
TERMINALS. FLURRIES MAY BE POSSIBLE AT KDBQ OR KMLI. ..LE..
&&
.PREV DISCUSSION... /ISSUED 244 PM CST THU DEC 15 2011/
SYNOPSIS...
12Z UA ANALYSIS HAS A LLJ RUNNING FROM OKLAHOMA INTO NEW ENGLAND.
SEVERAL TROFS RAN FROM THE WESTERN GREAT LAKES INTO THE NORTHERN
PLAINS WHERE ANOTHER LLJ WAS LOCATED. SATELLITE TRENDS THROUGH EARLY
AFTERNOON SHOW THE CLOUDS BEGINNING TO BREAK UP AS STRONG SUBSIDENCE
DEVELOPS ACROSS THE PLAINS AND UPPER MISSISSIPPI VALLEY.
18Z SFC ANALYSIS HAS THE COLD FRONT FROM LAKE HURON INTO EASTERN
TEXAS WITH HIGH PRESSURE IN THE PLAINS. SEVERAL TROFS RAN FROM THE
WESTERN LAKES INTO THE UPPER MISSISSIPPI VALLEY. DEW POINTS AHEAD OF
THE FRONT WERE IN THE 50S AND 60S WITH 30S AND 40S IMMEDIATELY
BEHIND THE FRONT. DEW POINTS IN THE TEENS AND 20S WERE IN THE PLAINS
AND PARTS OF THE MIDWEST.
SHORT TERM...TONIGHT AND FRIDAY...
QUIET WX WITH SEASONABLE TEMPERATURES WILL BE SEEN TONIGHT AND
FRIDAY. WINDS WILL CONTINUE TO DECREASE LATE THIS AFTERNOON AND
EVENING AS THE STRONGEST ISALLOBARIC CHANGE CONTINUES TO MOVE EAST
OF THE AREA. RUC TRENDS INDICATE THAT STRONG SUBSIDENCE IS
DEVELOPING BEHIND THE DEPARTING SHORTWAVE AND SATELLITE DOES SHOW
MORE BREAKS BEGINNING TO DEVELOP IN THE CLOUD SHIELD.
BASED ON CURRENT SATELLITE AND RUC TRENDS...CLOUDS WILL CONTINUE TO
SLOWLY BREAK UP FOR THE REMAINDER OF THE AFTERNOON WITH CLEARING
DEVELOPING ACROSS THE CWFA LATE THIS AFTERNOON OR EVENING.
08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
A WEAK CLIPPER SHOULD SLIDE SOUTHEAST FRIDAY EVENING...BRINGING SOME
MID CLOUDS TO THE CWA...AND AN OUTSIDE CHANCE FOR A SNOW
SHOWER...BUT MORE LIKELY FLURRIES IN THE NORTH. THIS VERY MINOR
EVENT PASSES QUICKLY FRIDAY NIGHT AND LEAVES SATURDAY AND SUNDAY
WITH VERY PLEASANT LATE FALL WEATHER. HIGHS IN THE MID TO UPPER 30S
SATURDAY AND LOWER TO MID 40S SUNDAY. THIS ENDS THE PERIOD OF HIGH
CONFIDENCE IN THE EXTENDED.
THE MODELS ARE IN TWO CAMPS NOW WITH RESPECT TO THE MONDAY THROUGH
WEDNESDAY STORM. THE GEM...UKMET...AND GFS RUNS SINCE 00Z LAST NIGHT
HAVE GONE FARTHER NORTH...AND BRING A SIMILAR STORM TO THE MIDWEST
THAN WAS SEEN IN THE PAST 2 DAYS. HOWEVER...THE ECMWF HAS TRENDED
SOUTH...AND CLIPS THE CWA WITH LIGHT SNOW ON TUESDAY/TUESDAY NIGHT.
THE MAJOR DIFFERENCE BETWEEN THESE MODELS BOILS DOWN TO HOW THEY
HANDLE A SEPARATE SHORT WAVE THAT ENTERS THE PACIFIC NORTHWEST
SATURDAY. THE GEM/UK/GFS ALL BRING THAT STORM INTO THE WA/OR
COAST...AND PHASE THAT WAVE/KICK THE CLOSED LOW NORTHEASTWARD AND
THEREFORE DEVELOP A SIGNIFICANT MIDWEST STORM. THE ECMWF BRINGS THIS
WAVE INTO CENTRAL BRITISH COLUMBIA...AND AS IT MOVES IT EAST...IT
OVER TOPS THE RIDGE ON THE WEST COAST VS KICKING THE LOW OUT WITH
IT. AFTER OVERTOPPING...IT SWEEPS HIGH PRESSURE AND COLD AIR DOWN
INTO THE MIDWEST FOR EARLY WEEK AND THEREFORE SUPPRESSES THE STORM
SYSTEM SOUTH. SUCH A SMALL DIFFERENCE...RESULTS IN A MAJOR
DIFFERENCES IN OUR WEATHER. THIS WAVE IN QUESTION IS REAL...BUT
FOUND OVER THE NORTH CENTRAL PACIFIC OCEAN AS OF NOW...AND IS WITHIN
A FAST BAND OF WESTERLY FLOW SOUTH OF A MAJOR ALEUTIAN LOW.
THUS...GLOBAL MODELS WILL NO LIKELY LOCK CORRECTLY ONTO ITS POSITION
AND STRENGTH FOR SOME DAYS. PREDICTING THE WEATHER IS A
CHALLENGE...BUT THIS ONE WILL TAKE TIME TO BE WORKED OUT. UNTIL WE
KNOW FOR SURE WHAT LATITUDE THIS WAVE MAKES LANDFALL IN THE PAC
NORTHWEST...WE WILL NO KNOW WHETHER IT OVERTOPS OR PHASES/KICKS OUT
OUR CLOSED LOW IN THE SOUTHWEST. TIME WILL CERTAINLY TELL.
OUR FORECAST REMAINS WET TO START...AND SNOWY TO END THIS
STORM...POPS ARE LOW...BUT SHOULD THE NORTHERN TRACK BY CORRECT...WE
NEED MUCH HIGHER POPS FOR THIS EVENT.
WEDNESDAY AND THURSDAY...ALL GLOBAL MODELS SHOW THE PATTERN
RELOADING FOR ANOTHER CUT OFF LOW IN THE SOUTHWEST. THIS SHOULD
PROVIDE ANOTHER DAY OR TWO OF QUIET WEATHER BEFORE ANOTHER POTENTIAL
EVENT.
ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
236 AM MST FRI DEC 16 2011
.SHORT TERM (TODAY-SUNDAY)...
233 AM MST FRI DEC 16 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW SPLIT-FLOW PATTERN
ACROSS THE EASTERN CONUS...WITH CUTOFF LOW OVER THE BAJA PENINSULA.
CWA CURRENTLY BETWEEN SHORTWAVE TROUGHS...WITH LARGE SCALE
SUBSIDENCE CURRENTLY IN PLACE.
EARLY THIS MORNING...FOG CHANCES HAVE DIMINISHED ACROSS EASTERN
COLORADO. 06Z NAM WOULD KEEP AND FOG/STRATUS SW OF CWA. LATEST RUC
DOESNT BRING BL RH VALUES ABOVE 75% ANYWHERE IN EASTERN COLORADO. I
COULDNT COMPLETELY RULE OUT ISOLATED POCKETS OF FOG NEAR SUNRISE IN
NEAR EXTREME SW PART OF CWA...BUT CONFIDENCE IS TOO LOW TO KEEP
MENTION IN FORECAST FOR NOW.
TODAY-SUNDAY NIGHT...SHORTWAVE TROUGH CURRENTLY OVER SE WYOMING WILL
SWING ACROSS THE CWA TODAY. WITH DEEP DRY LAYER IN PLACE...WILL
ONLY SEE PERIOD OF MID-HIGH CLOUDS. SHORTWAVE RIDGE BUILDS OVER CWA
SAT AND SUNDAY...WITH WARM AND DRY CONDITIONS EXPECTED. HIGHS IN LOW
50S ACROSS MOST SOUTH AND WESTERN LOCATIONS SEEMS REASONABLE SAT. I
MAY STILL BE GIVING LINGERING SNOW COVER TOO MUCH CREDIT ACROSS THE NE
PART OF CWA ON SAT AFTER ANOTHER DAY OF MELTING TODAY. GUIDANCE
SHOWING GOOD WAA SUNDAY AHEAD OF CUTOFF LOW AS IT BEGINS TO MOVE
TOWARDS FOUR CORNERS REGION. H85 TEMPS AROUND 10C ACROSS CWA PROGGED
BY MOST GUIDANCE...AND NO LINGERING IMPACTS FROM SNOW COVER
EXPECTED. I CURRENTLY HAVE MID-UPPER 50S IN THE SOUTH AND LOWER 50S
IN THE NORTH WHICH STILL MAY END UP BEING TOO LOW.
DR
.LONG TERM (MONDAY-THURSDAY)...
233 AM MST FRI DEC 16 2011
THE GFS AND NAM ARE IN BETTER AGREEMENT AND MORE PROGRESSIVE THAN
IN THE ECMWF IN BRINGING THE UPPER LOW CENTER INTO THE CENTRAL
TEXAS PANHANDLE REGION BY MID DAY MONDAY. THE ECMWF IS DELAYED
SEVERAL HOURS AND DOESN`T BRING IT INTO A SIMILAR POSITION UNTIL
MONDAY EVENING. THE LOW CENTER IS AS DEEP ON THE ECMWF AS THE
GFS...BUT THE TROUGH THE LOW IN PHASING INTO...AND THE SUBSEQUENT
SECONDARY TROUGH AXIS ACTING AS THE KICKER...ISN`T AS DEEP ON THE
ECMWF. THEREFORE...WHILE CONFIDENCE IS INCREASING FOR MONDAY`S
SOLUTION...CONFIDENCE DIMINISHES THROUGH THE WEEK.
CURRENTLY...IT APPEARS THE SURFACE LOW CENTER EMERGES IN EASTERN NEW
MEXICO AND TRACKS THROUGH THE TEXAS PANHANDLE REGION ON MONDAY WITH
PRECIPITATION SPREADING NORTHWARD INTO THE FORECAST AREA THROUGH THE
DAY AND THEN TAPERING OFF FROM WEST TO EAST AS THE LOW CONTINUES TO
THE EAST NORTHEAST. EXPECT GOOD COLD AIR ADVECTION DURING THE DAY
WITH SOME OVERRUNNING EARLY MONDAY MORNING FOR A POSSIBLE RAIN AND
SNOW MIX THAT CHANGES OVER TO ALL SNOW BY LATE IN THE DAY.
CURRENTLY...ONLY 1-2 INCHES OF SNOW AT THE MOST IS EXPECTED
PRIMARILY ACROSS THE SOUTHEAST PORTION OF THE FORECAST AREA. EXPECT
CLEARING OVERNIGHT MONDAY NIGHT AS THE SYSTEM MOVES FAIRLY QUICKLY
OFF TO THE EAST.
TEMPERATURES WILL WARM SOME TUESDAY AND WEDNESDAY AS A SHORT WAVE
RIDGE ALOFT MOVES ACROSS THE REGION WITH TEMPERATURES EXPECTED TO
COOL AGAIN LATE IN THE WEEK AS THE JET SAGS SOUTH AND ANOTHER TROUGH
TRANSITIONS THE CENTRAL HIGH PLAINS REGION THURSDAY AND FRIDAY.
LOCKHART
&&
.AVIATION...
950 PM MST THU DEC 15 2011
FOR THE 06Z TAFS...AN OUTSIDE CHANCE FOR MVFR-LEVEL REDUCED VIS
EXISTS OVERNIGHT PRIMARILY AT KMCK MAINLY DUE TO LIGHTER WIND
SPEEDS HERE WITH AN EXISTING SNOW PACK. WILL INSERT A LOW VFR VIS
GROUP TO INDICATE AS SUCH. SHOULD SUB-VFR VIS MATERIALIZE IT WILL
RAPIDLY SCATTER SHORTLY AFTER SUNRISE. OTHERWISE VFR CONDITIONS
WILL PREVAIL THROUGH THE PERIOD. WIND SPEEDS WILL REMAIN
RELATIVELY LIGHT THROUGHOUT BUT WILL SHIFT FROM THE S/SW OVERNIGHT
TO THE W/NW BY LATE MORNING/EARLY AFTERNOON AS A WEAK COLD FRONT
PUSHES ACROSS THE AREA.
050
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
401 AM EST FRI DEC 16 2011
.SYNOPSIS...
MUCH COLDER AIR WILL SETTLE IN OVER THE UPPER OHIO VALLEY THIS
WEEKEND. A WEAK STORM SYSTEM WILL BRING THE CHANCE FOR SNOW
SHOWERS SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLDER AIR HAS SETTLED IN OVER THE AREA. WILL CONTINUE WITH A DRY
FORECAST TODAY. AREA OF VERY DRY MID-LEVEL AIR IS PROGGED TO MOVE
IN OVER THE UPPER OHIO VALLEY THIS MORNING. THIS WILL CONTINUE TO
LOWER INVERSIONS AND PREVENT LES SHOWERS FROM DEVELOPING.
EXPECT A DECREASE IN CLOUD COVER LATER THIS MORNING, WHICH WILL
ALLOW FOR SOME SUNSHINE.
TEMPERATURES WILL BE BELOW NORMAL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
HIGH PRESSURE WILL ALLOW FOR MAINLY DRY WEATHER TONIGHT. WILL
NEED TO INCLUDE A MENTION OF CHC/SCHC POPS LATE TONIGHT AND SAT
MORNING ACROSS THE NORTH AND RIDGES AS MID-LEVEL TROUGH WILL
BRING ANOTHER SHOT OF CAA AND REINFORCE THE NW FLOW.
COLD FRONT WILL CROSS THE AREA SATURDAY NIGHT. PLENTY OF UL
SUPPORT WITH THIS BOUNDARY AND CAA. WILL INCREASE POPS EVERYWHERE
SATURDAY NIGHT INTO SUNDAY MORNING. THERE MAY BE SOME
ACCUMULATIONS, MAINLY ACROSS THE NORTH AND RIDGES.
ON SUNDAY, LOWER AND MID LEVEL FLOW WILL BEGIN TO TURN WESTERLY
AND SNOW SHOWERS WILL DIMINISH WITH TEMPERATURES AGAIN AROUND
NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE MODELS CONTINUE TO FLIP-FLOP ON SOLUTIONS FOR SYSTEM
WHICH WILL EFFECT THE REGION NEXT WEEK. WILL MAKE ONLY MINOR
CHANGES TO LONG TERM.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
PER RECENT SURFACE AND SATELLITE DATA PLUS HRRR AND NAM MODEL
OUTPUT, EXPECT BRISK WESTERLY LOWLEVEL WINDS TO PRODUCE SCATTERED TO
BROKEN STRATOCUMULUS AT MAINLY VFR LEVELS. NAM MODEL PROFILES SHOW
SURFACE WINDS CAN GUST TO 30 KTS AT TIMES UNTIL 08Z-12Z, THEN
SLACKEN TO MAINLY 10-15 KTS DAYTIME FRIDAY.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
SURFACE RIDGE SHOULD PROVIDE GENERALLY VFR CONDITIONS FRIDAY NIGHT
INTO EARLY SATURDAY. A SHORT WAVE TROUGH AND ASSOCIATED WEAK SURFACE
FRONT, MOVING ACROSS THE GREAT LAKES, WILL BRING SCATTERED SNOW
SHOWERS AND THE POTENTIAL FOR RESTRICTIONS SATURDAY AFTERNOON INTO
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
114 AM EST FRI DEC 16 2011
.SYNOPSIS...
MUCH COLDER AIR WILL MOVE INTO THE UPPER OHIO VALLEY THIS WEEKEND.
A WEAK SYSTEM WILL BRING THE CHANCE FOR SNOW SHOWERS SATURDAY
NIGHT AND SUNDAY.
&&
.NEAR TERM /THROUGH TODAY/...
COLD FRONT HAS PASSED TO THE EAST OF THE AREA AND COLDER AIR IS
RAPIDLY POURING IN. WILL GO WITH A DRY FORECAST FOR THE REMAINDER
OF THE NIGHT. WILL NEED TO WATCH ACROSS THE NORTH AS SOME LES
SHOWERS COULD DEVELOP BEFORE DAWN, BUT INVERSIONS ARE SINKING AS
VERY DRY MID-LEVEL AIR IS CROSSING THE REGION.
COLD DAY WITH SOME SUNSHINE AS MID-LEVEL NORTHWEST FLOW WILL
CONTINUE TO PROVIDE CAA. WITH PLENTY OF DRY AIR IN THE MID-LEVELS,
DO NOT EXPECT ANY LES TO DEVELOP.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL ALLOW FOR MAINLY DRY WEATHER TONIGHT. WILL
NEED TO INCLUDE A MENTION OF CHC/SCHC POPS LATE TONIGHT AND SAT
MORNING ACROSS THE NORTH AND RIDGES AS MID-LEVEL TROUGH WILL
BRING ANOTHER SHOT OF CAA AND REINFORCE THE NW FLOW.
COLD FRONT WILL CROSS THE AREA SATURDAY NIGHT. PLENTY OF UL
SUPPORT WITH THIS BOUNDARY AND CAA. WILL INCREASE POPS EVERYWHERE
SATURDAY NIGHT INTO SUNDAY MORNING. THERE MAY BE SOME
ACCUMULATIONS, MAINLY ACROSS THE NORTH AND RIDGES.
ON SUNDAY, LOWER AND MID LEVEL FLOW WILL BEGIN TO TURN WESTERLY
AND SNOW SHOWERS WILL DIMINISH WITH TEMPERATURES AGAIN AROUND
NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE MODELS CONTINUE TO FLIP-FLOP ON SOLUTIONS FOR SYSTEM
WHICH WILL EFFECT THE REGION NEXT WEEK. WILL MAKE ONLY MINOR
CHANGES TO LONG TERM.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
PER RECENT SURFACE AND SATELLITE DATA PLUS HRRR AND NAM MODEL
OUTPUT, EXPECT BRISK WESTERLY LOWLEVEL WINDS TO PRODUCE SCATTERED TO
BROKEN STRATOCUMULUS AT MAINLY VFR LEVELS. NAM MODEL PROFILES SHOW
SURFACE WINDS CAN GUST TO 30 KTS AT TIMES UNTIL 08Z-12Z, THEN
SLACKEN TO MAINLY 10-15 KTS DAYTIME FRIDAY.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
SURFACE RIDGE SHOULD PROVIDE GENERALLY VFR CONDITIONS FRIDAY NIGHT
INTO EARLY SATURDAY. A SHORT WAVE TROUGH AND ASSOCIATED WEAK SURFACE
FRONT, MOVING ACROSS THE GREAT LAKES, WILL BRING SCATTERED SNOW
SHOWERS AND THE POTENTIAL FOR RESTRICTIONS SATURDAY AFTERNOON INTO
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
455 AM EST FRI DEC 16 2011
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RIDGING INTO WRN CANADA
AND A DOWNSTREAM TROF EXTENDING S INTO THE NRN PLAINS/GREAT LAKES.
FLOW IS SPLIT WITH A WEAKER SRN STREAM FEATURING A MID LEVEL LOW
OVER SRN CA AND A WEAK SHORTWAVE OVER THE SRN PLAINS. A POTENT
SHORTWAVE PASSED THRU THE UPPER GREAT LAKES LAST EVENING...BRINGING
A BOUT OF STRONG WINDS OVER LAKE SUPERIOR AND LAKE ENHANCED SNOW IN
ITS WAKE. WINDS GUSTED TO 58MPH AT GRAND MARAIS AND 61MPH AT
STANNARD ROCK. LES HAS NOTABLY DIMINISHED OVER THE LAST FEW HRS AS
FAST WNW FLOW IS PUSHING SYSTEMS ALONG QUICKLY. NEXT WEAK SHORTWAVE
TROF IS MOVING INTO THE DAKOTAS AND MANITOBA. A MORE IMPORTANT
SHORTWAVE IS TOPPING THE WRN CANADA RIDGE OVER NRN BRITISH COLUMBIA
AND THE SRN YUKON.
&&
.DISCUSSION...
WEATHER THRU THIS FCST PERIOD WILL BE DOMINATED BY A MEAN RIDGE OF
VARYING AMPLITUDE OVER WRN CANADA AND A DOWNSTREAM POLAR VORTEX IN
THE VCNTY OF NRN HUDSON BAY/BAFFIN ISLAND. END RESULT SHOULD BE
SEVERAL QUICK MOVING NRN STREAM SHORTWAVES WITH VERY LITTLE PCPN
OUTSIDE OF AREAS AFFECTED BY SOME LAKE EFFECT/LAKE ENHANCED SNOW
ASSOCIATED WITH PASSING WAVES. FLOW ALSO LOOKS TO REMAIN SPLIT WITH
SRN STREAM WAVES AND ASSOCIATED PCPN PASSING S OF UPPER MI.
OVERALL...IT WILL NOT BE AN ESPECIALLY WINTRY PATTERN HEADING TOWARD
THE LATTER PORTION OF DEC AS NORTHERLY POSITION OF POLAR VORTEX
LARGELY HOLDS ARCTIC AIR N OF THE AREA. ONLY BRIEF INTRUSIONS OF
COLDER AIR WILL OCCUR OVER THE NEXT 7 DAYS.
FOR TODAY...DESPITE 850MB TEMPS IN THE -14 TO -16C RANGE...ONGOING
LES WILL HAVE TO FIGHT DRY AIR/LOW INVERSION. 00Z KINL SOUNDING
SHOWED INVERSION BASED AROUND 875MB/4000FT MSL. NAM/GFS FCST
SOUNDINGS HAVE A GOOD HANDLE ON THIS. ALTHOUGH CONVECTION WILL BE
SHALLOW...THE DENDRITIC SNOW GROWTH TEMP ZONE WILL BE WITHIN THE
CONVECTIVE LAYER. SO...THERE SHOULD BE SOME LIGHT FLUFFY SNOW
ACCUMULATION TODAY OF AN INCH...MAYBE TWO...WHERE LES IS MORE
PERSISTENT. WEAK SHORTWAVE OVER THE DAKOTAS/MANITOBA WILL HAVE
LITTLE IMPACT ON LES THIS AFTN/EVENING AS WEAK QVECTOR DIVERGENCE
DOMINATES. GFS/NAM HAVE ALSO BACKED OFF ON DEEPENING OF MOISTURE
PROFILE WITH PASSING WAVE. LES AFFECTING NW/WNW FLOW FAVORED AREAS
TODAY WILL SHIFT TONIGHT AS WINDS BACK SW AHEAD OF STRONGER
SHORTWAVE (CURRENTLY OVER NRN BRITISH COLUMBIA/SRN YUKON) DROPPING
SE THRU SASKATCHEWAN/MANITOBA.
AS SHORTWAVE DROPS SE THRU THE UPPER GREAT LAKES SAT...HEALTHY DEEP
LAYER FORCING PER QVECTORS WILL OVERSPREAD THE AREA. COMBINED WITH
STEEP MIDLEVEL LAPSE RATES UPWARDS OF 7.5C/KM...WAVE MAY BE ABLE TO
SQUEEZE OUT A BRIEF PERIOD OF LIGHT SNOW AT MOST LOCATIONS. ANY
SYNOPTIC SNOW ACCUMULATION SHOULD BE UNDER AN INCH. 850MB TEMPS
AROUND -10C WILL SUPPORT SOME LAKE ENHANCEMENT OVER WRN UPPER MI AS
WINDS SHIFT FROM SW TO NW. A FEW INCHES OF SNOW CERTAINLY POSSIBLE
OVER THE NW SAT AFTN INTO EARLY SAT EVENING. BRIEF ENHANCEMENT WILL
SHIFT INTO AREAS E OF KMQT SAT EVENING AS WINDS SHIFT NW. THERE MAY
BE SOME LAKE ENHANCEMENT OFF NRN LAKE MICHIGAN INTO THE FAR ERN FCST
AREA SAT AFTN IN THE SW FLOW AHEAD OF THE SHORTWAVE. RIGHT NOW...IT
APPEARS WINDS WILL HAVE TOO MUCH A WRLY COMPONENT TO OFFER MUCH
ENHANCEMENT POTENTIAL FOR SCHOOLCRAFT/LUCE COUNTIES. NW FLOW LES
WILL RAPIDLY DIMINISH SAT NIGHT FROM W TO E AS AIRMASS QUICKLY DRIES
AND INVERSION CRASHES TO 4KFT OR LOWER.
WAA WILL BE UNDERWAY SUN AS NEXT SHORTWAVE MOVES ACROSS SCNTRL
CANADA. ALL GUIDANCE SHOW ASSOCIATED SFC LOW PASSING N OF UPPER MI
SUN NIGHT. WAA/ISENTROPIC ASCENT IS STRONG SUN WITH 40+KT WINDS
ORIENTED PERPENDICULAR TO TIGHTLY SPACED ISOBARS. HOWEVER..AIRMASS
IS VERY DRY AT THE LOWER LEVELS. AT THIS POINT...PLAN TO CARRY A DRY
FCST SUN/SUN NIGHT WITH ANY PCPN N OF UPPER MI. SHALLOW MOISTURE
DROPPING INTO THE AREA BEHIND COLD FRONT WITH 850MB TEMPS FALLING
PERHAPS TO AROUND -12C MAY SUPPORT SOME LIGHT LES/FLURRIES OFF LAKE
SUPERIOR MON INTO MON NIGHT.
TWO MORE SHORTWAVES WILL PASS ACROSS THE AREA DURING THE MIDDLE OF
NEXT WEEK...TUE AND THU. PCPN CHANCES APPEAR LIMITED...AND AIR MASS
MAY NOT EVEN BE COLD ENOUGH TO SUPPORT MUCH IF ANY LAKE EFFECT.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
AT KSAW...EXPECT MVFR CONDITIONS TO PREVAIL THROUGH THE FCST PD.
SOME LINGERING SNOW IS POSSIBLE INTO THE EARLY OVERNIGHT WITH A
STRONG NW FLOW...BUT AS NW WINDS DECREASE LATE TONIGHT AND DRIER AIR
MOVES IN FROM THE WEST EXPECT SNOW TO TAPER OFF TO SCT FLURRIES.
AT KCMX AND KIWD...EXPECT MVFR CONDITIONS TO PREVAIL THROUGH THE
PERIOD IN A WNW FLOW. ANY LINGERING IFR VBSYS IN SNOW AND BLOWING
SNOW THIS EVENING SHOULD IMPROVE TO MVFR BY TAF TIME AS WIND GUSTS
DECREASE AND DRIER AIR MOVES IN FROM THE WEST.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
STRONG GALE EVENT WITH EVEN SOME STORM FORCE GUSTS HAS WOUND DOWN.
WINDS BECOME LESS THAN 20 KTS THROUGH TONIGHT AS HIGH PRESSURE
RIDGE SETTLES ACROSS. LIGHT WINDS ARE BRIEF THOUGH AS STRONG AND
QUITE CHANGEABLE WINDS ARE THEN EXPECTED THROUGH EARLY NEXT WEEK.
SOUTHWEST WINDS INCREASE TO 30 KTS ON SATURDAY AS LOW PRESSURE
TROUGH APPROACHES. DESPITE WARM AIR ADVECTION AND HIGHER
STABILITY...STRONG PRESSURE FALLS NORTH OF LK SUPERIOR MAY LEAD TO
GALE FORCE GUSTS OVR CNTRL LK SUPERIOR BTWN KEWEENAW AND ISLE ROYALE
SATURDAY AFTERNOON AND EVENING. WINDS SHIFT NORTHWEST BEHIND TROUGH
BUT THE ARRIVAL OF YET ANOTHER TROUGH FM NORTHWEST ON SUNDAY LEADS
TO MORE STRONG SOUTHWEST WINDS SUNDAY AFTERNOON AND EVENING. GALES
APPEAR POSSIBLE OVR CNTRL LK SUPERIOR ONCE AGAIN. WINDS STAY BTWN
20-30 KTS FOR EARLY NEXT WEEK AS ANOTHER TROUGH IS FORECAST TO MOVE
ACROSS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1140 PM EST THU DEC 15 2011
LATEST UPDATE...AVIATION...
.SYNOPSIS...(340 PM EST THU DEC 15 2011)
A COLDER AIRMASS CONTINUES TO FILTER INTO SOUTHWEST LOWER MICHIGAN
IN THE WAKE OF A THURSDAY MORNING COLD FRONTAL PASSAGE. WEST TO
NORTHWEST WINDS WILL DROP LOWS INTO THE 20S IN MOST LOCATIONS
TONIGHT. IT WILL BE WINDY THIS EVENING BEFORE WINDS SUBSIDE
CONSIDERABLY OVERNIGHT. LAKE EFFECT SNOW SHOWERS ARE EXPECTED THIS
EVENING AND AGAIN FRIDAY NIGHT INTO SATURDAY. ACCUMULATIONS WILL BE
LIGHT TONIGHT ON THE ORDER OF A DUSTING TO POSSIBLY A HALF INCH IN A
FEW SPOTS. LOCALIZED ACCUMULATIONS FRIDAY NIGHT INTO SATURDAY MAY
REACH AN INCH OR TWO...BUT MOST LOCATIONS WILL SEE VERY LITTLE
ACCUMULATION. EVEN WITH THE COOL DOWN...TEMPERATURES WILL REMAIN
SLIGHTLY ABOVE NORMAL INTO THE WEEKEND.
&&
.SHORT TERM...(1100 PM EST THU DEC 15 2011)
(TONIGHT THROUGH SATURDAY NIGHT)
WE ARE ALLOWING THE WIND ADVISORY HEADLINE FOR OUR LAKESHORE
COUNTIES
TO EXPIRE AT 11 PM. AT 04Z SFC OBS INDICATE WIND SPEEDS ARE STARTING
TO DECREASE SOMEWHAT AND THE DIMINISHING TREND OF WINDS WILL
CONTINUE OVERNIGHT.
REMAINDER OF PREVIOUS SHORT TERM FCST DISCUSSION FOLLOWS...AS FOR
LAKE EFFECT SNOW CHANCES...THERE ARE TWO TIME FRAMES OF
POTENTIAL. THE FIRST BEING THIS EVENING...WHERE DEEPER MOISTURE
INTERACTS WITH INCREASING INSTABILITY. THE DEEPER MOISTURE IS ONLY
IN PLACE THROUGH THE 03Z TO 06Z TIME FRAME THOUGH AFTER WHICH TIME
IT DWINDLES TO 4000-5000FT OR LESS. THIS EVENING...EXPECT SNOW
SHOWER ACTIVITY WITH LIGHT ACCUMULATIONS (INCH OR LESS) ACROSS
CENTRAL LOWER MICHIGAN AND POSSIBLY ALONG THE HIGHWAY 131 CORRIDOR
(GIVEN THE STIFF WESTERLY WINDS DISPLACING BANDS INLAND A BIT). A
WET WARM GROUND WILL COUNTERACT THE SNOW SHOWERS SOME.
RELATIVE HUMIDITY IS QUITE LACKING IN THE OVERNIGHT THROUGH FRIDAY
EVENING TIME FRAME AND THEREFORE NOT EXPECTING MUCH IN THE WAY OF
SNOW SHOWERS DESPITE DELTA T/S IN THE MIDDLE TEENS C.
A COUPLE OF SHORTWAVE TROUGHS ROTATE THROUGH THE REGION FRIDAY NIGHT
INTO SATURDAY WHICH SHOULD GIVE A BOOST TO LAKE EFFECT CLOUDS AND
SNOW SHOWERS. SOME MINOR ACCUMULATIONS ARE POSSIBLE ALONG AND WEST
OF HIGHWAY 131. ENVISION DUSTING TO HALF INCH ACCUMS IN MOST
AREAS...BUT SOME LOCALIZED ACCUMS OF AN INCH OR TWO WILL BE
POSSIBLE.
&&
.LONG TERM...(340 PM EST THU DEC 15 2011)
(SUNDAY THROUGH THURSDAY)
SUNDAY LOOKS DRY AS A SFC HIGH AND NW FLOW ALOFT PRODUCES SOME
SUNSHINE ACROSS THE GREAT LAKES.
MODELS CONTINUE TO BE ON DIFFERENT PAGES WRT THE SRN STREAM LOW
MONDAY AND TUESDAY. BOTH THE ECMWF/GFS SHOW A SRN STREAM SHORT WAVE
BEING KICKED NEWD BY A NRN STREAM WAVE. THE ECMWF HOWEVER TAKES THE
LOW MORE EWD THROUGH THE OHIO VALLEY VS THE GFS THAT TAKES THE LOW
OVER LWR MI. BASED ON THE UPPER WAVE TRACK I TEND TO BUY THE GFS
TRACK MORE. THIS TRACK WOULD ALSO BRING WARMER AIR INTO THE CWA.
THUS WE/LL KEEP THE RAIN/SNOW MIX MON-TUE NIGHT. LIGHT SNOW POSSIBLE
ON THE BACK SIDE OF THE SYSTEM WEDNESDAY AS H8 TEMPS FALL TO -5C IN
NW FLOW. TEMPS WILL CONTINUE TO BE A FEW DEGREES WARMER THAN NORMAL
THROUGH THE PERIOD.
&&
.AVIATION...(1140 PM EST THU DEC 15 2011)
GUSTY WINDS WILL CONTINUE TO DIMINISH THROUGH 09Z AS THE PRESSURE
GRADIENT WEAKENS. CLOUDS SHOULD REMAIN VFR AT THE TAF SITES BUT
SOMEWHAT LOWER CONDITIONS POSSIBLE FURTHER NORTH TOWARD KRQB AND
KCAD. WE WILL BE BETWEEN SYSTEMS FRIDAY SO THE WEATHER IS EXPECTED
TO REMAIN VFR THROUGH THE DAY.
&&
.MARINE...(340 PM EST THU DEC 15 2011)
WILL MAINTAIN THE GALE WARNING THROUGH THIS EVENING AS THE CORE OF
THE WIND LOOKS TO COME THROUGH BETWEEN 400PM AND 1000PM. WE WILL
EXTEND THE GALE SLIGHTLY TO GIVE A LITTLE BIT OF A BUFFER ON THE
BACK END...THROUGH 100 AM. RUC OVERVIEW/S ALONG THE
COAST ARE SHOWING 40 KNOTS OF WIND DOWN TO AROUND 1000FT...WHICH
SHOULD TRANSLATE INTO FREQUENT GALE FORCE GUSTS AT THE COASTAL
SITES. WINDS WILL DROP BELOW GALE FORCE AFTER MIDNIGHT AND WE WILL
NEED A SMALL CRAFT ADVISORY THAT WILL STRETCH INTO THE DAYLIGHT
HOURS OF FRIDAY. SUB SMALL CRAFT ADVISORIES CONDITIONS ARE EXPECTED
FROM FRIDAY EVENING INTO SUNDAY.
&&
.HYDROLOGY...(340 PM EST THU DEC 15 2011)
ONE RIVER FLOOD WARNING (VICKSBURG) AND THREE RIVER FLOOD ADVISORIES
(IONIA...BURLINGTON AND HOLT) ARE CURRENTLY IN EFFECT. WE ARE NOT
EXPECTING MUCH IN THE WAY OF CHANGES TO RIVER HEADLINES AT THIS
POINT GIVEN THE RAINFALL HAS OCCURRED AND IS MAKING IT/S WAY INTO
THE RIVERS. RAINFALL TOTALS RANGED FROM A HALF INCH TO SLIGHTLY OVER
ONE INCH FOR THE LAST 24 HOURS OR SO. COLDER AIR IS NOW SURGING INTO
THE AREA AND THIS WILL ACT TO SLIGHTLY SUPPRESS RUN OFF SLIGHTLY.
SO...BOTTOM LINE RISES WILL CONTINUE THE NEXT COUPLE OF DAYS WITH
MOST SITES IN THE AREA REMAINING UNDER BANKFULL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING ENTIRE NEARSHORE AREA THROUGH 100 AM.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE/LAURENS
LONG TERM: 93
AVIATION: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1154 PM CST THU DEC 15 2011
.DISCUSSION...THE ADVERTISED WIDESPREAD LIGHT SNOW ACROSS WESTERN
NORTH DAKOTA CONTINUES TO PROGRESS EAST TONIGHT...NOW REACHING INTO
CENTRAL NORTH DAKOTA AND THE CITY OF BISMARCK. SURFACE LOW PRESSURE OVER
EASTERN MONTANA WILL WORK ITS WAY TO NEAR BISMARCK BY 12Z FRIDAY.
HAVE INCREASED POPS TO CATEGORICAL OVER MOST OF SOUTH CENTRAL NORTH
DAKOTA BASED ON LATEST SURFACE OBSERVATIONS AND RADAR TRENDS. THE
NAM TIME-HEIGHT CROSS SECTION CONTINUES TO SHOW THE BEST FORCING
APPROACHING TOWARD 12Z ACROSS KBIS. OVERALL SNOWFALL ACCUMULATIONS
OF AROUND ONE INCH OR LESS LOOKS ON TRACK. ALTHOUGH WE DID HAVE A
PUBLIC REPORT OF 1.5 INCHES AT WATFORD CITY EARLIER...BUT THE BACK
EDGE OF THE SNOW IS NOW APPROACHING THERE. MINOR UPDATES TO HOURLY
AND MINIMUM TEMPERATURES WHICH HAVE BEEN ADJUSTED BASED ON CLOUD
COVER AND UPSTREAM OBSERVATIONS. USED THE LATEST RUC TO UPDATE THE
HOURLY TEMPS THE REST OF THE NIGHT INTO FRIDAY MORNING.
&&
.AVIATION...AT 11 PM CST A LOW PRESSURE AREA OVER SOUTHEAST MONTANA
WAS ASSOCIATED WITH A WARM FRONT EXTENDING FROM THE LOW INTO
NORTHWEST SOUTH DAKOTA. THE LOW AND WARM FRONT WILL MOVE EAST
TONIGHT AND BE THE FOCUS FOR MVFR TO OCNL IFR CONDITIONS IN SNOW
THURSDAY NIGHT AND FRIDAY MORNING. KISN/KDIK/KMOT WILL BE MVFR IN
SNOW AND BR BETWEEN 06Z AND 12Z THEN IMPROVE TO VFR. KBIS CAN EXPECT
IFR CONDITIONS IN SNOW BETWEEN 06Z AND 10Z....IMPROVING TO MVFR
BETWEEN 10Z AND 16Z FRIDAY THEN VFR AFTER 18Z. KJMS WILL BECOME MVFR
AFTER 09Z IN SNOW...BECOMING VFR AFTER 18Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
AVIATION....WAA
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1138 PM CST THU DEC 15 2011
.AVIATION...
DISTURBANCE CONTINUES MAKING PROGRESS EAST...NOW INTO WEST TX.
BACK EDGE OF ASSOCIATED MID CLOUD DECK SHOULD CLEAR KLBB TERMINAL
SHORTLY AFTER 08Z THEN KCDS BY 10Z. WINDS REMAIN LIGHT E-NE
OVERNIGHT. LATEST NAM AND RUC INDICATE SOME LIGHT FG DEVELOPING
AROUND SUNRISE ACROSS S PLAINS. ALSO MODEL RH PROGS SHOW CLOUD
DECK CURRENTLY IN ERN NM AND WRN SOUTH PLAINS MAKING SOME PROGRESS
EAST. HAVE LEFT THIS OUT OF KLBB TAF FOR NOW AS LIKLIHOOD LOW FOR
WIDESPREAD MVFR CONDITIONS THAT FAR E WITH ONLY WEAK TO NEUTRAL
ISENTROPIC LIFT AND GENERAL DRYING TAKING PLACE.
&&
.PREV DISCUSSION... /ISSUED 856 PM CST THU DEC 15 2011/
UPDATE...
SHRTWV TROUGH OVER SE NM WILL MOVE ACROSS W TX OVERNIGHT. RADAR
INDICATES ACTIVITY ASSOCIATED WITH THIS FEATURE REMAINS WEAKLY
ORGANIZED ACROSS THE SW PORTION OF THE SOUTH PLAINS INTO SOUTHEAST
NM AND THE PERMIAN BASIN. HAVE EXTENDED MENTION OF
SPRINKLES/FLURRIES ACROSS MUCH OF THE REMAINDER OF THE AREA
OVERNIGHT AS ENERGY SPREADS INTO THE ROLLING PLAINS. TEMP/DPT SPREADS
HAVE DECREASED IN A FEW LOCATIONS INDICATING SOME OF THE PRECIP
WILL HAVE BETTER CHANCE OF REACHING THE GROUND AS IT MOVES EAST
AND NORTHEAST BUT THIS SHOULD REMAIN LIMITED. WITH WETBULB TEMPS
DROPPING TO NEAR FREEZING SOME LIQUID PRECIP COULD CHANGE TO SNOW
BEFORE COMING TO AN END.
PREV DISCUSSION... /ISSUED 354 PM CST THU DEC 15 2011/
SHORT TERM...
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY SHOW A POSITIVELY-TILTED
SHORTWAVE TROUGH IMMEDIATELY TO OUR WEST WITH WELL-DEFINED H5
VORTMAX LOCATED OVER SRN NM...WHICH WILL BE MOVING ACROSS WTX DURING
THE NEXT 6-9 HRS. MID-LVL ASCENT WITH THIS SYSTEM HAS RESULTED IN A
BAND OF LIGHT SHOWERS...MUCH OF WHICH VIRGA...FROM NEAR EL PASO
NEWD ACROSS SE NM...WHICH WERE EDGING CLOSE TO WRN COCHRAN AND
YOAKUM COUNTIES AT 3 PM. FARTHER EAST AND SOUTH...ISENTROPIC LIFT
OVER THIS MORNING/S COLD FRONT HAS MAINTAINED A BROAD EXPANSE OF
OVERCAST SKIES AND PERIODIC SHOWERS FROM THE ERN PERMIAN BASIN NEWD
THROUGH NORTH TEXAS. A FEW OF THESE SHOWERS HAVE PERIODICALLY
BRUSHED THE SRN ROLLING PLAINS. AT THE SFC...COOL AIR ADVECTION HAS
KEPT TEMPS IN THE LOWER 40S TO NEAR 50F RANGE ACROSS THE FA TODAY.
THIS EVENING...WHILE THE LARGE-SCALE LIFT CONTINUES...WE COULD SEE A
FEW VERY LIGHT SHOWERS MAINLY ACROSS SW AND SE PORTIONS OF THE FA.
WITH SFC DEWPOINT DEPRESSIONS RUNNING 15-20 DEGREES WE COULD EVEN
SEE A FEW FLURRIES MIX IN WITH THE SPRINKLES ON THE CAPROCK...BUT NO
ACCUMULATIONS ARE EXPECTED. PARTIAL CLEARING WILL FOLLOW THE EXITING
LIFT AFTER MIDNIGHT OR SO...AND A COOL EARLY MORNING IS IN STORE
AREA-WIDE WITH LIGHT E-NE WINDS. FRIDAY WILL FEATURE RIDGING AT THE
SFC AND ALOFT BRINGING MOSTLY SUNNY SKIES BUT CONTINUED COOL
TEMPS...WITH HIGHS MAINLY 45F TO 50F.
LONG TERM...
CONFIDENCE OVERALL HAS IMPROVED SUFFICIENTLY CONCERNING THE
BEHAVIOR OF AN IMPRESSIVE UPPER CYCLONE NOW CHURNING OVER SOCAL.
ALL MODELS ARE SURPRISINGLY IN GOOD HARMONY WITH THIS FEATURE
THROUGH THE WEEKEND BEFORE DEVIATIONS BECOME MORE EVIDENT ON
MONDAY. GFS ENSEMBLES ARE NOW TIGHTLY CLUSTERED WITH THE PATH OF
THE 500MB LOW THROUGH MONDAY NIGHT WITH MINIMAL NORTH-SOUTH
DEVIATION. SUCH STRONG AGREEMENT THIS FAR OUT IS UNUSUAL AND
CERTAINLY RAISES A FEW SUSPICIONS ESPECIALLY CONSIDERING THE FACT
THIS LOW HAS YET TO STALL OUT. THIS IS ONE FACTOR THAT THE MODELS
HAVE STRUGGLED WITH IN RECENT DAYS AS THEY HAVE ALL GRADUALLY
TRENDED SLOWER IN EJECTING THE UPPER CYCLONE. SO THERE REMAINS A
WINDOW FOR ADDITIONAL CHANGE IN LATER RUNS...BUT UNTIL THAT CHANGE
IS REALIZED AND PROVEN CREDIBLE...THIS FORECAST HAS TRENDED IN
LINE WITH A NORTHERLY UPPER LOW TRACK.
UPPER CYCLONE SHOULD TRACK GENERALLY NEAR OR JUST SOUTH OF I-40
ON MONDAY SUBJECTING ALL OF THE CWA TO WARM PHASE PRECIP BEFORE
DRY SLOTTING EMERGES MIDDAY. THEREAFTER...THERE REMAINS A WINDOW
FOR DEFORMATION ZONE PRECIP TO EXPAND SOUTHEAST INTO THE DRY SLOT
LATE MONDAY ACCOMPANIED BY CAA...HOWEVER DIMINISHED SATURATION
DEPTHS BY THIS TIME SHOULD CUT BACK ON SNOW AND SUBSEQUENT THREATS
FOR ACCUMULATION.
EC/GFS/CMC THEN DIVE ANOTHER CLOSED LOW INTO SOCAL BY EARLY NEXT
WEEK BEFORE QUICKLY LIFTING IT NORTHEAST AS AN OPEN WAVE. GIVEN
THE RECENT TENDENCY FOR MODELS THIS FAR OUT TO EJECT THESE CUTOFF
LOWS TOO SOON...WILL NOT ENTERTAIN POPS FOR MID-LATE WEEK YET AS
THIS SYSTEM COULD EASILY LINGER AROUND THE BAJA FOR AN EXTRA DAY
IF NOT LONGER.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 21 44 25 50 29 / 0 0 0 0 10
TULIA 22 45 24 52 30 / 0 0 0 0 10
PLAINVIEW 23 46 25 52 32 / 10 0 0 0 20
LEVELLAND 24 47 25 52 34 / 10 0 0 0 20
LUBBOCK 24 47 26 53 34 / 10 0 0 0 20
DENVER CITY 25 46 25 50 35 / 10 0 0 0 20
BROWNFIELD 25 47 27 51 35 / 10 0 0 0 20
CHILDRESS 28 49 29 55 34 / 10 0 0 0 10
SPUR 28 49 30 54 38 / 10 0 0 0 20
ASPERMONT 31 50 31 55 40 / 20 10 0 0 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
255 AM MST FRI DEC 16 2011
.SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT
TRANQUIL CONDITIONS EXPECTED IN THE SHORT TERM WITH TEMPERATURES
BEING THE PRIMARY FORECAST CHALLENGE.
CURRENTLY...SPLIT FLOW OVER WYOMING THIS MORNING WITH AN UPPER
LEVEL SHORTWAVE TRACKING ACROSS MONTANA/DAKOTAS AND AN UPPER LEVEL
LOW PRESSURE SYSTEM MOVING INTO SOUTHERN CALIFORNIA. CLOUD BAND
WITH THE SOUTHERN EDGE OF THE SHORTWAVE OVER WYOMING HAS BEEN
SHEARING APART AND WARMING ON IR IMAGERY. MOSAIC RADAR SHOWING NO
PRECIPITATION ECHOES ANYWHERE OVER WYOMING OR NEBRASKA PANHANDLE.
FOR TODAY...SHORTWAVE CONTINUES TO SHEAR OUT AND PUSHES THROUGH
THE SOUTHERN PANHANDLE BY EARLY AFTERNOON. WE THEN WILL BE IN
NORTHWEST FLOW BEHIND THE SHORTWAVE. WORST CASE CONDITIONS WILL BE
MOSTLY CLOUDY SKIES THROUGH MUCH OF THE MORNING WITH GRADUAL
SCATTERING OUT BY LATE AFTERNOON. EXPECT HIGH TEMPERATURES IN THE
LOW 40S EAST OF THE LARAMIE RANGE WITH UPPER 20S WEST. SOME OF THE
HIGHER TERRAIN AREAS AND OUR WIND PRONE AREAS MAY SEE SOME GUSTY
WEST TO NORTHWEST WINDS...BUT WELL BELOW ANY HEADLINE CRITERIA.
700MB TEMPERATURES BEGIN TO WARM THIS EVENING INTO
SATURDAY...INCREASING FROM -9C THIS MORNING TO AROUND 0C SATURDAY
MORNING. AS A RESULT...LOOKS LIKE MODERATELY WARM HIGHS EXPECTED
FOR THE WEEKEND WITH 50 HIGHS IN THE PANHANDLE TO THE EASTERN
SLOPES OF THE LARAMIE RANGE...UPPER 30S WEST. BCCONSMOS GUIDANCE
SEEMS TO BE THE BEST PERFORMING ON TEMPERATURES THE PAST WEEK AND
HAVE BLENDED MORE TOWARDS THIS GUIDANCE WITH THE WARMER 700MB
TEMPERATURES. WARMEST DAY LOOKS TO BE SUNDAY AS 700MB TEMPERATURES
CLIMB TO +4C. MID TO UPPER 50S POSSIBLE IN THE
PANHANDLE...ESPECIALLY THE SOUTHERN PORTIONS NEAR SIDNEY. WINDS TO
BEGIN INCREASING SUNDAY AFTERNOON...POSSIBLY GUSTING INTO THE 40
MPH RANGE FOR OUR WIND PRONE AREAS. THESE STRONGER WINDS WILL ADD TO
DOWNSLOPE WARMING AND WE MAY NEED TO UP TEMPERATURES EVEN MORE OUT
IN THE PANHANDLE FOR SUNDAY AFTERNOON. BY SUNDAY EARLY EVENING...A
DRY COLD FRONT LOOKS TO MOVE THROUGH SOUTHEAST WYOMING....WITH MAIN
IMPACT BEING ON TEMPERATURES AS 700MB TEMPS FALL TO -6 TO -8C.
.LONG TERM...MONDAY THROUGH THURSDAY. 500 MB SYNOPTIC PATTERNS
SIMILAR WITH THE 16/00Z GFS AND ECMWF RUNS...THOUGH THEY DIVERGE ON
THURSDAY. ON THURSDAY...16/00Z GFS TAKES ALL THE ENERGY WITH THE
SHORTWAVE TROUGH ALOFT INTO THE NORTHERN AND CENTRAL PLAINS STATES...
WHILE THE 16/00Z ECMWF KEEPS THE MAIN ENERGY WITH THE TROUGH ALOFT
BEGINNING TO CUT OFF OVER UTAH AND ARIZONA WITH THE WEAKER NORTHERN
PORTION OF THE TROUGH MOVING ACROSS THE NORTHERN PLAINS STATES.
SENSIBLE WEATHER FOR OUR COUNTIES WOULD CONTAIN MORE PRECIPITATION
AND CLOUDS FOR THURSDAY IF THE ECMWF SOLUTION VERIFIES CLOSER TO
REALITY VERSUS THE GFS SOLUTION.
MONDAY...CONSIDERABLY COLDER DAY TO START THE WEEK BEFORE CHRISTMAS
IN THE WAKE OF THE COLD FRONTAL PASSAGE. MAXIMUM TEMPERATURES IN THE
20S AND 30S WITH 1000-500 MB THICKNESSES NEAR 5310 METERS. FAIRLY
WIDESPREAD COVERAGE OF SNOW SHOWERS OVER THE NORTHERN LARAMIE...SNOWY
AND SIERRA MADRE RANGES IN THE MORNING THEN DECREASING SIGNIFICANTLY
IN THE AFTERNOON AS MOISTURE WANES. THOUGH POSITIVE TILT SHORTWAVE
TROUGH ALOFT MOVES ACROSS IN THE AFTERNOON...BULK OF THE
PRECIPITATION WILL BE OVER THE SOUTHERN PLAINS STATES CLOSER TO THE
PRIMARY UPPER TROUGH AND DEEPER MOISTURE.
TUESDAY...SLOW WARMING TREND AS NORTHWEST FLOW DEVELOPS...THOUGH
TEMPERED BY TIME OF YEAR CONSIDERATIONS AND LOW SUN ANGLE. DRY DUE
TO LACK OF LOW AND MID LEVEL MOISTURE AVAILABILITY. WILL SEE TYPICAL
WINDS INCREASE AS SURFACE THROUGH 700 MB GRADIENTS INCREASE...THOUGH
LOOKS LIKE WINDS WILL REMAIN UNDER HIGH WIND CRITERIA DUE TO PROGGED
700 MB GRADIENTS.
WEDNESDAY...NEXT PROGRESSIVE TROUGH ALOFT BEGINS CARVING ITSELF OUT
OVER IDAHO AND MONTANA SENDING AN ASSOCIATED COLD FRONT INTO
NORTHERN WYOMING BY LATE IN THE DAY. WILL SEE INCREASING MID AND
HIGH LEVEL CLOUDS ACROSS OUR COUNTIES IN ADVANCE OF THE SHORTWAVE
TROUGH ALOFT. MAXIMUM TEMPERATURES 20S AND 30S WEST IN THE HIGH
MOUNTAINS AND VALLEYS WHERE COLD AIR WILL REMAIN MOSTLY
TRAPPED...WITH UPPER 30S TO MID 40S EAST PER 1000-500 MB THICKNESSES
NEAR 5430 METERS AND SOME DOWNSLOPE KATABATIC WARMING.
THURSDAY...COLDER AGAIN IN THE WAKE OF THE RELATIVELY STRONG COLD
FRONTAL PASSAGE. MAXIMUM TEMPERATURES IN THE 20S AND 30S WITH
SURFACE HIGH PRESSURE SETTLING OVER WYOMING AND NEBRASKA AND
1000-500 MB THICKNESSES PROGGED NEAR 5250 METERS. LOOKS LIKE A
DECENT AREAL COVERAGE OF SNOW WITH THIS COLD FRONT AND SHORTWAVE
TROUGH ALOFT PASSAGE...THOUGH QPF WILL BE LIMITED DUE TO PROGRESSIVE
NATURE OF THE SHORTWAVE AND LIMITED LOW AND MID LEVEL MOISTURE. HAVE
PAINTED HIGHEST COVERAGE OF SNOW OVER OUR NORTHERN LARAMIE...SNOWY
AND SIERRA MADRE RANGES DUE TO OROGRAPHICS AND DYNAMICS WORKING IN
UNISON.
&&
.AVIATION...06Z TAF ISSUANCE...WEAK COLD FRONT MOVING THROUGH
CENTRAL WYOMING LATE THIS EVENING...PRECEDED BY MID/HIGH CLOUD
CEILINGS. BOTH THE 00Z NAM AND 02Z HRRR DATA INDICATE SOME
MVFR TO IFR CEILINGS AND PATCHY FOG DEVELOPING INTO SOUTHWEST
CARBON COUNTY OVERNIGHT...BUT SHOULD NOT IMPACT RAWLINS. WENT
WITH LOWEST CEILINGS AT 5000 FT AND WILL MONITOR TRENDS.
ELSEWHERE...EXPECT VFR CONDITIONS WITH VARIABLE TO SOUTHWEST
WINDS 5 TO 10 KT PRIOR TO THE FRONTAL PASSAGE. WINDS SHIFT TO
THE WEST TO NORTHWEST AFTER FROPA WITH SKIES CLEARING FROM WEST
TO EAST FRIDAY MORNING. IT WILL BECOME BREEZY WEST OF THE LARAMIE
RANGE WITH GUSTS OF 20 TO 25 KT.
&&
.FIRE WEATHER...DRY CONDITIONS EXPECTED TO CONTINUE THROUGH SUNDAY
WITH ABOVE NORMAL TEMPERATURES FOR HIGHS. AFTERNOON HUMIDITIES
EXPECTED TO FALL INTO THE LOW TO MID 20 PERCENT RANGE...WITH
EXCELLENT OVERNIGHT RECOVERIES. GUSTY WINDS EXPECTED TO DEVELOP
SUNDAY AHEAD OF A DRY COLD FRONT THAT IS EXPECTED TO MOVE THROUGH
SUNDAY EVENING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...CLAYCOMB
LONG TERM/AVIATION...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1036 PM MST THU DEC 15 2011
.AVIATION...06Z TAF ISSUANCE...WEAK COLD FRONT MOVING THROUGH
CENTRAL WYOMING LATE THIS EVENING...PRECEDED BY MID/HIGH CLOUD
CEILINGS. BOTH THE 00Z NAM AND 02Z HRRR DATA INDICATE SOME
MVFR TO IFR CEILINGS AND PATCHY FOG DEVELOPING INTO SOUTHWEST
CARBON COUNTY OVERNIGHT...BUT SHOULD NOT IMPACT RAWLINS. WENT
WITH LOWEST CEILINGS AT 5000 FT AND WILL MONITOR TRENDS.
ELSEWHERE...EXPECT VFR CONDITIONS WITH VARIABLE TO SOUTHWEST
WINDS 5 TO 10 KT PRIOR TO THE FRONTAL PASSAGE. WINDS SHIFT TO
THE WEST TO NORTHWEST AFTER FROPA WITH SKIES CLEARING FROM WEST
TO EAST FRIDAY MORNING. IT WILL BECOME BREEZY WEST OF THE LARAMIE
RANGE WITH GUSTS OF 20 TO 25 KT.
&&
PREV DISCUSSION... /ISSUED 352 PM MST THU DEC 15 2011/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...QUIET WEATHER WILL
CONTINUE INTO THE WEEKEND WITH MODELS SHOWING SPLIT FLOW ACROSS
THE WESTERN UNITED STATES AS AN UPPER LEVEL RIDGE ATTEMPTS TO PUSH
EASTWARD FROM THE EASTERN PACIFIC. THIS WILL RESULT IN THE STORM
TRACK FAR TO THE NORTH OF WYOMING AND NEBRASKA...WITH THE NORTHERN
BRANCH OF THE JET STREAM RETREATING INTO CANADA. THE SOUTHERN
BRANCH WILL REMAIN ACROSS MEXICO AND THE GULF COAST STATES AS AN
UPPER LEVEL TROUGH CURRENTLY ACROSS ARIZONA WILL BECOME A CLOSED
LOW OVER NORTHERN MEXICO AND REMAIN NEARLY STATIONARY THROUGH
SATURDAY. THE NORTHERN AND CENTRAL ROCKIES WILL IN BETWEEN THIS
JET ENERGY AND WILL THEREFORE BE RELATIVELY QUIET WITH LITTLE IF
ANY IMPACT. ANOTHER WEAK UPPER LEVEL TROUGH CURRENTLY OVER MONTANA
WILL PUSH SOUTHEAST ACROSS WYOMING EARLY ON FRIDAY. NO
PRECIPITATION IS EXPECTED WITH A WIND SHIFT INTO THE NORTHWEST THE
ONLY IMPACT FROM THIS DISTURBANCE. LOW STRATUS CLOUDS AND PATCHY
FOG IS POSSIBLE ACROSS FAR SOUTHWEST CARBON COUNTY TONIGHT...SO
ADDED PATCHY FOG TO THE FORECAST SOUTH OF RAWLINS.
OTHERWISE...TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL
THROUGH FRIDAY AS THE UPPER LEVEL TROUGH MOVES THROUGH THE
AREA...BUT WILL THEN MODERATE INTO THIS WEEKEND WITH HIGHS IN THE
UPPER 30S TO UPPER 40S ACROSS MOST OF THE AREA FOR SATURDAY. A FEW
LOCATIONS IN FAR SOUTHEAST WYOMING AND WESTERN NEBRASKA MAY SEE 50
FOR A HIGH AS WINDS SHIFT INTO THE WEST. LOW TEMPERATURES WILL BE
SEASONABLY COLD FOR THIS TIME OF THE YEAR WITH CLEAR SKIES AND
LIGHT WINDS.
LONG TERM...SUNDAY THROUGH THURSDAY...
PERSISTENT ZONAL JET WILL REMAIN ENTRENCHED UPSTREAM OVER THE
CENTRAL PACIFIC. THIS WILL MAINTAIN THE SPLIT FLOW PATTERN ACROSS
THE WESTERN CONUS THROUGH THE EXTENDED PERIOD. INITIALLY THE
CLOSED LOW NEAR THE BAJA OF CALIFORNIA WILL BEGIN TO LIFT
EAST/NORTHEAST ACROSS SOUTHERN ARIZONA/NEW MEXICO ON SUNDAY. THE
BRUNT OF THIS ENERGY WILL BE CONFINED SOUTH OF THE CWA.
MEANWHILE...A NRN STREAM SHORTWAVE WILL DRAG A MAINLY DRY SURFACE
COLD FRONT THROUGH THE REGION MONDAY NIGHT. THERE MAY BE A FEW
ISOLATED MOUNTAIN SNOW SHOWERS LATE SUNDAY NIGHT/EARLY MONDAY. ANY
ACCUMULATION FROM THIS ACTIVITY WILL REMAIN VERY LIGHT. SPLIT
FLOW WILL CONTINUE THROUGH THE MIDDLE OF NEXT WEEK...WITH A
ANOTHER CLOSED LOW TO BECOME CUT-OFF NR THE BAJA OF CALIFORNIA.
MEDIUM RANGE GUIDANCE HINT AT ANOTHER SHORTWAVE EMBEDDED WITHIN
THE NRN STREAM TO DROP SOUTHEAST THROUGH THE NRN ROCKIES TOWARDS
THE MIDDLE/END OF NEXT WEEK. MEDIUM RANGE GUIDANCE HAS TRENDED
SLOWER WITH THIS FEATURE CLOSING IT OFF NR THE GREAT BASIN. SO FOR NOW
HAVE LEFT THE GOING FORECAST DRY. AFTER AN ABOVE NORMAL DAY
TEMPERATURE WISE ON SUNDAY...TEMPERATURES WILL DROP BACK TO MORE
SEASONAL READINGS NEXT WEEK.
&&
FIRE WEATHER...NO FIRE WEATHER CONCERNS THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WINDS WILL CONTINUE TO BE RELATIVELY
LIGHT ACROSS THE AREA WITH MODERATE DAYTIME HUMIDITIES BETWEEN 30
TO 50 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...RJM
LONG TERM...HAHN
AVIATION...JAMSKI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
620 AM MST FRI DEC 16 2011
.SHORT TERM (TODAY-SUNDAY)...
233 AM MST FRI DEC 16 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW SPLIT-FLOW PATTERN
ACROSS THE EASTERN CONUS...WITH CUTOFF LOW OVER THE BAJA PENINSULA.
CWA CURRENTLY BETWEEN SHORTWAVE TROUGHS...WITH LARGE SCALE
SUBSIDENCE CURRENTLY IN PLACE.
EARLY THIS MORNING...FOG CHANCES HAVE DIMINISHED ACROSS EASTERN
COLORADO. 06Z NAM WOULD KEEP AND FOG/STRATUS SW OF CWA. LATEST RUC
DOESNT BRING BL RH VALUES ABOVE 75% ANYWHERE IN EASTERN COLORADO. I
COULDNT COMPLETELY RULE OUT ISOLATED POCKETS OF FOG NEAR SUNRISE IN
NEAR EXTREME SW PART OF CWA...BUT CONFIDENCE IS TOO LOW TO KEEP
MENTION IN FORECAST FOR NOW.
TODAY-SUNDAY NIGHT...SHORTWAVE TROUGH CURRENTLY OVER SE WYOMING WILL
SWING ACROSS THE CWA TODAY. WITH DEEP DRY LAYER IN PLACE...WILL
ONLY SEE PERIOD OF MID-HIGH CLOUDS. SHORTWAVE RIDGE BUILDS OVER CWA
SAT AND SUNDAY...WITH WARM AND DRY CONDITIONS EXPECTED. HIGHS IN LOW
50S ACROSS MOST SOUTH AND WESTERN LOCATIONS SEEMS REASONABLE SAT. I
MAY STILL BE GIVING LINGERING SNOW COVER TOO MUCH CREDIT ACROSS THE NE
PART OF CWA ON SAT AFTER ANOTHER DAY OF MELTING TODAY. GUIDANCE
SHOWING GOOD WAA SUNDAY AHEAD OF CUTOFF LOW AS IT BEGINS TO MOVE
TOWARDS FOUR CORNERS REGION. H85 TEMPS AROUND 10C ACROSS CWA PROGGED
BY MOST GUIDANCE...AND NO LINGERING IMPACTS FROM SNOW COVER
EXPECTED. I CURRENTLY HAVE MID-UPPER 50S IN THE SOUTH AND LOWER 50S
IN THE NORTH WHICH STILL MAY END UP BEING TOO LOW.
DR
.LONG TERM (MONDAY-THURSDAY)...
233 AM MST FRI DEC 16 2011
THE GFS AND NAM ARE IN BETTER AGREEMENT AND MORE PROGRESSIVE THAN
IN THE ECMWF IN BRINGING THE UPPER LOW CENTER INTO THE CENTRAL
TEXAS PANHANDLE REGION BY MID DAY MONDAY. THE ECMWF IS DELAYED
SEVERAL HOURS AND DOESN`T BRING IT INTO A SIMILAR POSITION UNTIL
MONDAY EVENING. THE LOW CENTER IS AS DEEP ON THE ECMWF AS THE
GFS...BUT THE TROUGH THE LOW IN PHASING INTO...AND THE SUBSEQUENT
SECONDARY TROUGH AXIS ACTING AS THE KICKER...ISN`T AS DEEP ON THE
ECMWF. THEREFORE...WHILE CONFIDENCE IS INCREASING FOR MONDAY`S
SOLUTION...CONFIDENCE DIMINISHES THROUGH THE WEEK.
CURRENTLY...IT APPEARS THE SURFACE LOW CENTER EMERGES IN EASTERN NEW
MEXICO AND TRACKS THROUGH THE TEXAS PANHANDLE REGION ON MONDAY WITH
PRECIPITATION SPREADING NORTHWARD INTO THE FORECAST AREA THROUGH THE
DAY AND THEN TAPERING OFF FROM WEST TO EAST AS THE LOW CONTINUES TO
THE EAST NORTHEAST. EXPECT GOOD COLD AIR ADVECTION DURING THE DAY
WITH SOME OVERRUNNING EARLY MONDAY MORNING FOR A POSSIBLE RAIN AND
SNOW MIX THAT CHANGES OVER TO ALL SNOW BY LATE IN THE DAY.
CURRENTLY...ONLY 1-2 INCHES OF SNOW AT THE MOST IS EXPECTED
PRIMARILY ACROSS THE SOUTHEAST PORTION OF THE FORECAST AREA. EXPECT
CLEARING OVERNIGHT MONDAY NIGHT AS THE SYSTEM MOVES FAIRLY QUICKLY
OFF TO THE EAST.
TEMPERATURES WILL WARM SOME TUESDAY AND WEDNESDAY AS A SHORT WAVE
RIDGE ALOFT MOVES ACROSS THE REGION WITH TEMPERATURES EXPECTED TO
COOL AGAIN LATE IN THE WEEK AS THE JET SAGS SOUTH AND ANOTHER TROUGH
TRANSITIONS THE CENTRAL HIGH PLAINS REGION THURSDAY AND FRIDAY.
LOCKHART
&&
.AVIATION...
609 AM MST FRI DEC 16 2011
VFR CONDITIONS WILL PREVAIL AT KMCK AND KGLD THROUGH FRIDAY AND
SATURDAY. LIGHT SOUTHWEST WINDS WILL TURN NORTHWEST DURING THE DAY
TODAY...AND BACK TO THE WEST SOUTHWEST AGAIN AFTER ABOUT 03Z THIS EVENING.
LOCKHART
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
646 AM EST FRI DEC 16 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RIDGING INTO WRN CANADA
AND A DOWNSTREAM TROF EXTENDING S INTO THE NRN PLAINS/GREAT LAKES.
FLOW IS SPLIT WITH A WEAKER SRN STREAM FEATURING A MID LEVEL LOW
OVER SRN CA AND A WEAK SHORTWAVE OVER THE SRN PLAINS. A POTENT
SHORTWAVE PASSED THRU THE UPPER GREAT LAKES LAST EVENING...BRINGING
A BOUT OF STRONG WINDS OVER LAKE SUPERIOR AND LAKE ENHANCED SNOW IN
ITS WAKE. WINDS GUSTED TO 58MPH AT GRAND MARAIS AND 61MPH AT
STANNARD ROCK. LES HAS NOTABLY DIMINISHED OVER THE LAST FEW HRS AS
FAST WNW FLOW IS PUSHING SYSTEMS ALONG QUICKLY. NEXT WEAK SHORTWAVE
TROF IS MOVING INTO THE DAKOTAS AND MANITOBA. A MORE IMPORTANT
SHORTWAVE IS TOPPING THE WRN CANADA RIDGE OVER NRN BRITISH COLUMBIA
AND THE SRN YUKON.
&&
.DISCUSSION...
WEATHER THRU THIS FCST PERIOD WILL BE DOMINATED BY A MEAN RIDGE OF
VARYING AMPLITUDE OVER WRN CANADA AND A DOWNSTREAM POLAR VORTEX IN
THE VCNTY OF NRN HUDSON BAY/BAFFIN ISLAND. END RESULT SHOULD BE
SEVERAL QUICK MOVING NRN STREAM SHORTWAVES WITH VERY LITTLE PCPN
OUTSIDE OF AREAS AFFECTED BY SOME LAKE EFFECT/LAKE ENHANCED SNOW
ASSOCIATED WITH PASSING WAVES. FLOW ALSO LOOKS TO REMAIN SPLIT WITH
SRN STREAM WAVES AND ASSOCIATED PCPN PASSING S OF UPPER MI.
OVERALL...IT WILL NOT BE AN ESPECIALLY WINTRY PATTERN HEADING TOWARD
THE LATTER PORTION OF DEC AS NORTHERLY POSITION OF POLAR VORTEX
LARGELY HOLDS ARCTIC AIR N OF THE AREA. ONLY BRIEF INTRUSIONS OF
COLDER AIR WILL OCCUR OVER THE NEXT 7 DAYS.
FOR TODAY...DESPITE 850MB TEMPS IN THE -14 TO -16C RANGE...ONGOING
LES WILL HAVE TO FIGHT DRY AIR/LOW INVERSION. 00Z KINL SOUNDING
SHOWED INVERSION BASED AROUND 875MB/4000FT MSL. NAM/GFS FCST
SOUNDINGS HAVE A GOOD HANDLE ON THIS. ALTHOUGH CONVECTION WILL BE
SHALLOW...THE DENDRITIC SNOW GROWTH TEMP ZONE WILL BE WITHIN THE
CONVECTIVE LAYER. SO...THERE SHOULD BE SOME LIGHT FLUFFY SNOW
ACCUMULATION TODAY OF AN INCH...MAYBE TWO...WHERE LES IS MORE
PERSISTENT. WEAK SHORTWAVE OVER THE DAKOTAS/MANITOBA WILL HAVE
LITTLE IMPACT ON LES THIS AFTN/EVENING AS WEAK QVECTOR DIVERGENCE
DOMINATES. GFS/NAM HAVE ALSO BACKED OFF ON DEEPENING OF MOISTURE
PROFILE WITH PASSING WAVE. LES AFFECTING NW/WNW FLOW FAVORED AREAS
TODAY WILL SHIFT TONIGHT AS WINDS BACK SW AHEAD OF STRONGER
SHORTWAVE (CURRENTLY OVER NRN BRITISH COLUMBIA/SRN YUKON) DROPPING
SE THRU SASKATCHEWAN/MANITOBA.
AS SHORTWAVE DROPS SE THRU THE UPPER GREAT LAKES SAT...HEALTHY DEEP
LAYER FORCING PER QVECTORS WILL OVERSPREAD THE AREA. COMBINED WITH
STEEP MIDLEVEL LAPSE RATES UPWARDS OF 7.5C/KM...WAVE MAY BE ABLE TO
SQUEEZE OUT A BRIEF PERIOD OF LIGHT SNOW AT MOST LOCATIONS. ANY
SYNOPTIC SNOW ACCUMULATION SHOULD BE UNDER AN INCH. 850MB TEMPS
AROUND -10C WILL SUPPORT SOME LAKE ENHANCEMENT OVER WRN UPPER MI AS
WINDS SHIFT FROM SW TO NW. A FEW INCHES OF SNOW CERTAINLY POSSIBLE
OVER THE NW SAT AFTN INTO EARLY SAT EVENING. BRIEF ENHANCEMENT WILL
SHIFT INTO AREAS E OF KMQT SAT EVENING AS WINDS SHIFT NW. THERE MAY
BE SOME LAKE ENHANCEMENT OFF NRN LAKE MICHIGAN INTO THE FAR ERN FCST
AREA SAT AFTN IN THE SW FLOW AHEAD OF THE SHORTWAVE. RIGHT NOW...IT
APPEARS WINDS WILL HAVE TOO MUCH A WRLY COMPONENT TO OFFER MUCH
ENHANCEMENT POTENTIAL FOR SCHOOLCRAFT/LUCE COUNTIES. NW FLOW LES
WILL RAPIDLY DIMINISH SAT NIGHT FROM W TO E AS AIRMASS QUICKLY DRIES
AND INVERSION CRASHES TO 4KFT OR LOWER.
WAA WILL BE UNDERWAY SUN AS NEXT SHORTWAVE MOVES ACROSS SCNTRL
CANADA. ALL GUIDANCE SHOW ASSOCIATED SFC LOW PASSING N OF UPPER MI
SUN NIGHT. WAA/ISENTROPIC ASCENT IS STRONG SUN WITH 40+KT WINDS
ORIENTED PERPENDICULAR TO TIGHTLY SPACED ISOBARS. HOWEVER..AIRMASS
IS VERY DRY AT THE LOWER LEVELS. AT THIS POINT...PLAN TO CARRY A DRY
FCST SUN/SUN NIGHT WITH ANY PCPN N OF UPPER MI. SHALLOW MOISTURE
DROPPING INTO THE AREA BEHIND COLD FRONT WITH 850MB TEMPS FALLING
PERHAPS TO AROUND -12C MAY SUPPORT SOME LIGHT LES/FLURRIES OFF LAKE
SUPERIOR MON INTO MON NIGHT.
TWO MORE SHORTWAVES WILL PASS ACROSS THE AREA DURING THE MIDDLE OF
NEXT WEEK...TUE AND THU. PCPN CHANCES APPEAR LIMITED...AND AIR MASS
MAY NOT EVEN BE COLD ENOUGH TO SUPPORT MUCH IF ANY LAKE EFFECT.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
NORTHWEST WINDS FLOWING ACROSS LK SUPERIOR WILL KEEP CHANCES OF LK
EFFECT SNOWS ACROSS MUCH OF UPR MICHIGAN. EXPECT IFR CONDITIONS IN
THE MORNING AT KCMX AS UPPER WAVE MOVES ACROSS AND ENHANCES ONGOING
SNOW SHOWERS. OTHERWISE...OCCASIONAL FLURRIES WITH MVFR CONDITIONS
ARE IN FCST AT KIWD AND KSAW. BY TONIGHT...JUST SOME MID CLOUDS WILL
BE PUSHING ACROSS THE UPPER LAKES. EXPECT VFR CONDITIONS AT ALL THE
TAF SITES TONIGHT.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
STRONG GALE EVENT WITH EVEN SOME STORM FORCE GUSTS HAS WOUND DOWN.
WINDS BECOME LESS THAN 20 KTS THROUGH TONIGHT AS HIGH PRESSURE
RIDGE SETTLES ACROSS. LIGHT WINDS ARE BRIEF THOUGH AS STRONG AND
QUITE CHANGEABLE WINDS ARE THEN EXPECTED THROUGH EARLY NEXT WEEK.
SOUTHWEST WINDS INCREASE TO 30 KTS ON SATURDAY AS LOW PRESSURE
TROUGH APPROACHES. DESPITE WARM AIR ADVECTION AND HIGHER
STABILITY...STRONG PRESSURE FALLS NORTH OF LK SUPERIOR MAY LEAD TO
GALE FORCE GUSTS OVR CNTRL LK SUPERIOR BTWN KEWEENAW AND ISLE ROYALE
SATURDAY AFTERNOON AND EVENING. WINDS SHIFT NORTHWEST BEHIND TROUGH
BUT THE ARRIVAL OF YET ANOTHER TROUGH FM NORTHWEST ON SUNDAY LEADS
TO MORE STRONG SOUTHWEST WINDS SUNDAY AFTERNOON AND EVENING. GALES
APPEAR POSSIBLE OVR CNTRL LK SUPERIOR ONCE AGAIN. WINDS STAY BTWN
20-30 KTS FOR EARLY NEXT WEEK AS ANOTHER TROUGH IS FORECAST TO MOVE
ACROSS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
536 AM CST FRI DEC 16 2011
UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
DECENT BUT NOT STRONG WARM ADEVCTION PATTERN WITH SYSTEM OVER THE
DAKOTAS AND THERE HAVE BEEN A FEW OBSERVATIONS WITH VSBYS LESS
THAN 3SM. THE WARM ADVECTION PATTERN APPEARS TO BECOME A BIT MORE
BROAD AS IT SPREADS SOUTHEAST...BUT THE LATEST RUC DOES HOLD ON TO
A CENTER OF QG INSTANTANEOUS PRECIP RATE INTO WEST CENTRAL AND SOUTH
CENTRAL MINNESOTA DURING THE AFTERNOON. THE CHANCES OF MEASURABLE
SNOW ARE SLIM BUT THERE IS ENOUGH OF A SIGNAL TO INCLUDE A SMALL
AREA OF POPS ON A TRACK THROUGH THE ABOVE MENTIONED AREA...WITH
FLURRIES OVER A LARGER AREA. THIS FEATURED MAY STILL BE AFFECTING
SOUTH CENTRAL OR SOUTHEAST MINNESOTA THIS EVENING. A STRONGER WARM
ADVECTION PATTERN WITH ANOTHER WAVE DROPPING SOUTHEAST THROUGH
NORTHWEST ONTARIO INTO THE GREAT LAKES...MAY BRUSH NORTHWEST
WISCONSIN WITH LIGHT SNOW MID DAY ON SATURDAY.
THIS WILL SET UP MOST OF THE CWA IN THE WARM SECTOR SATURDAY NIGHT
AND SUNDAY. IT IT STILL LOOKS WARM...ALTHOUGH THE STRENGTH OF THE
850 MB TEMP ANOMALY IS NOT TOO EXTREME. IT SHOULD BE WARMER THAN
MOST OF THE STANDARD GUIDANCE BUT CLOSER TO THE ECMWF AND A FEW
OF THE BIAS CORRECTED VALUES. A DRY COLD FRONT IS THEN FORECAST TO
MOVE THROUGH LATE SUNDAY NIGHT WITH GUSTY WINDS FOR MONDAY. STILL
NO SIGNIFICANT CHANCE FOR PRECIP WITH THE SPLIT FLOW..WITH OUR
AREA JUST AFFECTED BY SYSTEMS MOVING ACROSS SOUTHERN CANADA IN
THE WEST TO NORTHWEST FLOW. THERE WILL BE ANOTHER CHANCE OF A
MILD DAY MID WEEK...AHEAD OF THE NEXT IN A SERIES FRONTS MOVING
ACROSS THE AREA. THERE MAY A CHANCE OF SOME INTERACTION WITH THE
SOUTHERN STREAM AFTER THE FRONT MOVES THOUGH MID WEEK. WE ONLY
HAVE A SMALL CHANCE OF SNOW OVER MAINLY THE SOUTHERN CWA ON
THURSDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
LVFR TO HIGH END MVFR CEILINGS DEVELOPING OVER THE TAF SITES DURING
THE AFTERNOON. A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL PASS
TO THE NORTH AND EAST OF OUR FORECAST AREA TODAY/SATURDAY. ANY LIGHT
SNOW OR FLURRIES THAT OCCURS FROM TIME TO TIME SHOULD NOT BE A
PROBLEM...VISIBILITIES SHOULD BE MORE THAN 5 MILES.
KMSP...VFR CONDITIONS WILL PREVAIL THROUGH LATER THIS AFTERNOON.
CEILING HEIGHTS LOWERING TO AROUND 3000 FEET AGL THIS EVENING.
WINDS LIGHT AND VARIABLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
407 AM CST FRI DEC 16 2011
.DISCUSSION...
DECENT BUT NOT STRONG WARM ADEVCTION PATTERN WITH SYSTEM OVER THE
DAKOTAS AND THERE HAVE BEEN A FEW OBSERVATIONS WITH VSBYS LESS
THAN 3SM. THE WARM ADVECTION PATTERN APPEARS TO BECOME A BIT MORE
BROAD AS IT SPREADS SOUTHEAST...BUT THE LATEST RUC DOES HOLD ON TO
A CENTER OF QG INSTANTANEOUS PRECIP RATE INTO WEST CENTRAL AND SOUTH
CENTRAL MINNESOTA DURING THE AFTERNOON. THE CHANCES OF MEASURABLE
SNOW ARE SLIM BUT THERE IS ENOUGH OF A SIGNAL TO INCLUDE A SMALL
AREA OF POPS ON A TRACK THROUGH THE ABOVE MENTIONED AREA...WITH
FLURRIES OVER A LARGER AREA. THIS FEATURED MAY STILL BE AFFECTING
SOUTH CENTRAL OR SOUTHEAST MINNESOTA THIS EVENING. A STRONGER WARM
ADVECTION PATTERN WITH ANOTHER WAVE DROPPING SOUTHEAST THROUGH
NORTHWEST ONTARIO INTO THE GREAT LAKES...MAY BRUSH NORTHWEST
WISCONSIN WITH LIGHT SNOW MID DAY ON SATURDAY.
THIS WILL SET UP MOST OF THE CWA IN THE WARM SECTOR SATURDAY NIGHT
AND SUNDAY. IT IT STILL LOOKS WARM...ALTHOUGH THE STRENGTH OF THE
850 MB TEMP ANOMALY IS NOT TOO EXTREME. IT SHOULD BE WARMER THAN
MOST OF THE STANDARD GUIDANCE BUT CLOSER TO THE ECMWF AND A FEW
OF THE BIAS CORRECTED VALUES. A DRY COLD FRONT IS THEN FORECAST TO
MOVE THROUGH LATE SUNDAY NIGHT WITH GUSTY WINDS FOR MONDAY. STILL
NO SIGNIFICANT CHANCE FOR PRECIP WITH THE SPLIT FLOW..WITH OUR
AREA JUST AFFECTED BY SYSTEMS MOVING ACROSS SOUTHERN CANADA IN
THE WEST TO NORTHWEST FLOW. THERE WILL BE ANOTHER CHANCE OF A
MILD DAY MID WEEK...AHEAD OF THE NEXT IN A SERIES FRONTS MOVING
ACROSS THE AREA. THERE MAY A CHANCE OF SOME INTERACTION WITH THE
SOUTHERN STREAM AFTER THE FRONT MOVES THOUGH MID WEEK. WE ONLY
HAVE A SMALL CHANCE OF SNOW OVER MAINLY THE SOUTHERN CWA ON
THURSDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
SFC WINDS HAVE DECREASED MARKEDLY DURING THE EVENING AS SURFACE HIGH
HAS ADVANCED TO W MN BORDER. SFC RIDGE WILL CONTINUE TO MOVE EAST
TO NEAR WI BORDER BY 18Z. SKC ATTM BUT CLOUDS HAVE BEEN ADVANCING
ACROSS THE DKTS AHEAD OF WEAK UPPER TROF NOW INTO NW NODAK. MODELS
HAVE TURNED DRIER ON PCPN WITH THIS SYSTEM AS MOVES ACROSS AREA ON
FRIDAY...BUT MAY SEE SOME FLURRIES IN WAA AHEAD OF TROF. KEPT VSBYS
ABOVE 6SM AT TAF SITES. CLOUDS IN LOW END VFR OR HIGH END MVFR
SHOULD REACH AXN AROUND 11Z AND THEN SPREAD EASTWARD DURING THE
MORNING/EARLY AFTN.
KMSP...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. MID/HIGH LEVEL
CLOUDS DEVELOPING AHEAD OF NEXT SYSTEM WITH CEILINGS LOWERING TO 4K
FEET AS SYSTEM MOVES INTO THE AREA FRI AFTERNOON. WILL MENTION SOME
FLURRIES AS SYSTEM DROPS SOUTH AND WEAKENS. NORTHWEST SURFACE WINDS
WILL CONTINUE TO WEAKEN OVERNIGHT AND MAY BECOME VARIABLE FOR A TIME
FRIDAY AFTERNOON BEFORE TURNING LIGHT SE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/BAP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
509 AM MST FRI DEC 16 2011
.AVIATION...12Z TAFS. THROUGH 16Z...AREAS OF IFR CEILINGS AND
VISIBILITIES IN FOG ACROSS FAR WESTERN CARBON COUNTY SOUTHWEST
OF RAWLINS...OTHERWISE VFR ELSEWHERE. BATCH OF SCATTERED TO
BROKEN MID LEVEL CLOUDS NEAR 10000 FEET AGL EAST OF A CHEYENNE TO
CHADRON LINE THROUGH 16Z...OTHERWISE FEW IF ANY CLOUDS. RUBIN
&&
.PREV DISCUSSION... /ISSUED 255 AM MST FRI DEC 16 2011/
SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT
TRANQUIL CONDITIONS EXPECTED IN THE SHORT TERM WITH TEMPERATURES
BEING THE PRIMARY FORECAST CHALLENGE.
CURRENTLY...SPLIT FLOW OVER WYOMING THIS MORNING WITH AN UPPER
LEVEL SHORTWAVE TRACKING ACROSS MONTANA/DAKOTAS AND AN UPPER LEVEL
LOW PRESSURE SYSTEM MOVING INTO SOUTHERN CALIFORNIA. CLOUD BAND
WITH THE SOUTHERN EDGE OF THE SHORTWAVE OVER WYOMING HAS BEEN
SHEARING APART AND WARMING ON IR IMAGERY. MOSAIC RADAR SHOWING NO
PRECIPITATION ECHOES ANYWHERE OVER WYOMING OR NEBRASKA PANHANDLE.
FOR TODAY...SHORTWAVE CONTINUES TO SHEAR OUT AND PUSHES THROUGH
THE SOUTHERN PANHANDLE BY EARLY AFTERNOON. WE THEN WILL BE IN
NORTHWEST FLOW BEHIND THE SHORTWAVE. WORST CASE CONDITIONS WILL BE
MOSTLY CLOUDY SKIES THROUGH MUCH OF THE MORNING WITH GRADUAL
SCATTERING OUT BY LATE AFTERNOON. EXPECT HIGH TEMPERATURES IN THE
LOW 40S EAST OF THE LARAMIE RANGE WITH UPPER 20S WEST. SOME OF THE
HIGHER TERRAIN AREAS AND OUR WIND PRONE AREAS MAY SEE SOME GUSTY
WEST TO NORTHWEST WINDS...BUT WELL BELOW ANY HEADLINE CRITERIA.
700MB TEMPERATURES BEGIN TO WARM THIS EVENING INTO
SATURDAY...INCREASING FROM -9C THIS MORNING TO AROUND 0C SATURDAY
MORNING. AS A RESULT...LOOKS LIKE MODERATELY WARM HIGHS EXPECTED
FOR THE WEEKEND WITH 50 HIGHS IN THE PANHANDLE TO THE EASTERN
SLOPES OF THE LARAMIE RANGE...UPPER 30S WEST. BCCONSMOS GUIDANCE
SEEMS TO BE THE BEST PERFORMING ON TEMPERATURES THE PAST WEEK AND
HAVE BLENDED MORE TOWARDS THIS GUIDANCE WITH THE WARMER 700MB
TEMPERATURES. WARMEST DAY LOOKS TO BE SUNDAY AS 700MB TEMPERATURES
CLIMB TO +4C. MID TO UPPER 50S POSSIBLE IN THE
PANHANDLE...ESPECIALLY THE SOUTHERN PORTIONS NEAR SIDNEY. WINDS TO
BEGIN INCREASING SUNDAY AFTERNOON...POSSIBLY GUSTING INTO THE 40
MPH RANGE FOR OUR WIND PRONE AREAS. THESE STRONGER WINDS WILL ADD TO
DOWNSLOPE WARMING AND WE MAY NEED TO UP TEMPERATURES EVEN MORE OUT
IN THE PANHANDLE FOR SUNDAY AFTERNOON. BY SUNDAY EARLY EVENING...A
DRY COLD FRONT LOOKS TO MOVE THROUGH SOUTHEAST WYOMING....WITH MAIN
IMPACT BEING ON TEMPERATURES AS 700MB TEMPS FALL TO -6 TO -8C.
LONG TERM...MONDAY THROUGH THURSDAY. 500 MB SYNOPTIC PATTERNS
SIMILAR WITH THE 16/00Z GFS AND ECMWF RUNS...THOUGH THEY DIVERGE ON
THURSDAY. ON THURSDAY...16/00Z GFS TAKES ALL THE ENERGY WITH THE
SHORTWAVE TROUGH ALOFT INTO THE NORTHERN AND CENTRAL PLAINS STATES...
WHILE THE 16/00Z ECMWF KEEPS THE MAIN ENERGY WITH THE TROUGH ALOFT
BEGINNING TO CUT OFF OVER UTAH AND ARIZONA WITH THE WEAKER NORTHERN
PORTION OF THE TROUGH MOVING ACROSS THE NORTHERN PLAINS STATES.
SENSIBLE WEATHER FOR OUR COUNTIES WOULD CONTAIN MORE PRECIPITATION
AND CLOUDS FOR THURSDAY IF THE ECMWF SOLUTION VERIFIES CLOSER TO
REALITY VERSUS THE GFS SOLUTION.
MONDAY...CONSIDERABLY COLDER DAY TO START THE WEEK BEFORE CHRISTMAS
IN THE WAKE OF THE COLD FRONTAL PASSAGE. MAXIMUM TEMPERATURES IN THE
20S AND 30S WITH 1000-500 MB THICKNESSES NEAR 5310 METERS. FAIRLY
WIDESPREAD COVERAGE OF SNOW SHOWERS OVER THE NORTHERN LARAMIE...SNOWY
AND SIERRA MADRE RANGES IN THE MORNING THEN DECREASING SIGNIFICANTLY
IN THE AFTERNOON AS MOISTURE WANES. THOUGH POSITIVE TILT SHORTWAVE
TROUGH ALOFT MOVES ACROSS IN THE AFTERNOON...BULK OF THE
PRECIPITATION WILL BE OVER THE SOUTHERN PLAINS STATES CLOSER TO THE
PRIMARY UPPER TROUGH AND DEEPER MOISTURE.
TUESDAY...SLOW WARMING TREND AS NORTHWEST FLOW DEVELOPS...THOUGH
TEMPERED BY TIME OF YEAR CONSIDERATIONS AND LOW SUN ANGLE. DRY DUE
TO LACK OF LOW AND MID LEVEL MOISTURE AVAILABILITY. WILL SEE TYPICAL
WINDS INCREASE AS SURFACE THROUGH 700 MB GRADIENTS INCREASE...THOUGH
LOOKS LIKE WINDS WILL REMAIN UNDER HIGH WIND CRITERIA DUE TO PROGGED
700 MB GRADIENTS.
WEDNESDAY...NEXT PROGRESSIVE TROUGH ALOFT BEGINS CARVING ITSELF OUT
OVER IDAHO AND MONTANA SENDING AN ASSOCIATED COLD FRONT INTO
NORTHERN WYOMING BY LATE IN THE DAY. WILL SEE INCREASING MID AND
HIGH LEVEL CLOUDS ACROSS OUR COUNTIES IN ADVANCE OF THE SHORTWAVE
TROUGH ALOFT. MAXIMUM TEMPERATURES 20S AND 30S WEST IN THE HIGH
MOUNTAINS AND VALLEYS WHERE COLD AIR WILL REMAIN MOSTLY
TRAPPED...WITH UPPER 30S TO MID 40S EAST PER 1000-500 MB THICKNESSES
NEAR 5430 METERS AND SOME DOWNSLOPE KATABATIC WARMING.
THURSDAY...COLDER AGAIN IN THE WAKE OF THE RELATIVELY STRONG COLD
FRONTAL PASSAGE. MAXIMUM TEMPERATURES IN THE 20S AND 30S WITH
SURFACE HIGH PRESSURE SETTLING OVER WYOMING AND NEBRASKA AND
1000-500 MB THICKNESSES PROGGED NEAR 5250 METERS. LOOKS LIKE A
DECENT AREAL COVERAGE OF SNOW WITH THIS COLD FRONT AND SHORTWAVE
TROUGH ALOFT PASSAGE...THOUGH QPF WILL BE LIMITED DUE TO PROGRESSIVE
NATURE OF THE SHORTWAVE AND LIMITED LOW AND MID LEVEL MOISTURE. HAVE
PAINTED HIGHEST COVERAGE OF SNOW OVER OUR NORTHERN LARAMIE...SNOWY
AND SIERRA MADRE RANGES DUE TO OROGRAPHICS AND DYNAMICS WORKING IN
UNISON.
AVIATION...06Z TAF ISSUANCE...WEAK COLD FRONT MOVING THROUGH
CENTRAL WYOMING LATE THIS EVENING...PRECEDED BY MID/HIGH CLOUD
CEILINGS. BOTH THE 00Z NAM AND 02Z HRRR DATA INDICATE SOME
MVFR TO IFR CEILINGS AND PATCHY FOG DEVELOPING INTO SOUTHWEST
CARBON COUNTY OVERNIGHT...BUT SHOULD NOT IMPACT RAWLINS. WENT
WITH LOWEST CEILINGS AT 5000 FT AND WILL MONITOR TRENDS.
ELSEWHERE...EXPECT VFR CONDITIONS WITH VARIABLE TO SOUTHWEST
WINDS 5 TO 10 KT PRIOR TO THE FRONTAL PASSAGE. WINDS SHIFT TO
THE WEST TO NORTHWEST AFTER FROPA WITH SKIES CLEARING FROM WEST
TO EAST FRIDAY MORNING. IT WILL BECOME BREEZY WEST OF THE LARAMIE
RANGE WITH GUSTS OF 20 TO 25 KT.
FIRE WEATHER...DRY CONDITIONS EXPECTED TO CONTINUE THROUGH SUNDAY
WITH ABOVE NORMAL TEMPERATURES FOR HIGHS. AFTERNOON HUMIDITIES
EXPECTED TO FALL INTO THE LOW TO MID 20 PERCENT RANGE...WITH
EXCELLENT OVERNIGHT RECOVERIES. GUSTY WINDS EXPECTED TO DEVELOP
SUNDAY AHEAD OF A DRY COLD FRONT THAT IS EXPECTED TO MOVE THROUGH
SUNDAY EVENING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...CLAYCOMB
LONG TERM/AVIATION...RUBIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
402 PM EST FRI DEC 16 2011
.SYNOPSIS...
HIGH PRESSURE BUILDING OVER THE AREA HAS PUSHED A FRONTAL SYSTEM
WELL TO OUR SOUTH. A WAVE OF LOW PRESSURE WILL MOVE EAST ALONG THE
FRONT OVERNIGHT AND LIKELY BRING SOME LIGHT RAIN OR SNOW TO DELMARVA
AND FAR SOUTHERN NEW JERSEY. HIGH PRESSURE WILL THEN BRING FAIR
WEATHER FOR THE WEEKEND AND EARLY NEXT WEEK WITH A WARMING TREND
AFTER SUNDAY. LOW PRESSURE APPROACHING FROM THE SOUTHWEST COULD
BRING MORE RAIN AROUND THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
HIGH POPS FOR MID LVL FGEN GENERATED SNOW MELTING IN THE BL OVER S
DE TO CAPE MAP NJ BETWEEN 23Z-08Z. THE 12Z/16 EC WHICH IS RELATIVELY
DRY AT 950 AND 850 MB IS STILL OFFERING QPF WHERE WE HAVE IT IN THE
GRIDS FOR 3 SUCCESSIVE 6 HR PERIODS. THIS PLUS THE QPF EVALUATION
BELOW SUPPORT THE HIGH PROB LOW QPF EVENT FAR S EDGE OF THE FA FOR A
TIME TONIGHT.
18Z 6 HR PCPN EVALUATION FROM 12Z/16 MODELS: THE UKMET APPEARS
TO BE TOO SLOW AND TOO FAR SOUTH AT 18Z WITH ITS MASS FIELDS OF RH.
THEREFORE IT WAS NOT A SIGNIFICANT CONSIDERATION IN THE AFTERNOON
FCST. NAM WAS TOO SLOW AND TOO FAR SOUTH AS WELL. 18Z NAM LOOKS
BETTER AND CONTINUES THE QPF TREND OF ITS PREDECESSOR TO VCNTY
KDOV-KWWD LINE TONIGHT.
15Z SREF HAS COME AROUND TO THE FURTHER N SOLN...USUALLY HANGING ON
THE COATTAILS OF ITS 12Z NAM RUN. SO...THE 12Z GFS OP AND 12Z/16 EC
COMBO LOOK BEST FOR RAPID EXTRAPOLATION ENEWD WITH CONTD SUPPORT
FROM THE 18Z NAM AND 15Z SREF. THE 12Z GEFS PROB FOR .05 WAS VERY
GOOD AT 18Z AND THE 98 PCT PROB FOR .05 IN S DE ENDING AT 06Z LOOKS
LIKE A VERY GOOD FCST ATTM. 15Z SREF .01 PROB NOW UP TO 70 PCT IN S
DE.
SO WHILE A COUPLE OF 12Z/16 NON NCEP MODELS APPEAR TOO SLOW AND
TOO FAR SOUTH ... CONFIDENCE FOR A CATEGORICAL EVENT IS A LITTLE
LESS THAN IDEAL BUT STILL ABOVE AVG FOR S DE AND POSSIBLY CAPE MAY
NJ.
MESOSCALE MODELS: 12Z SPC WRF IS A DECENT FIT FOR REALITY AT 18Z AND
A FCST WHICH IS FASTER AND FURTHER N THAN ITS 00Z VSN. STILL LOOKS A
LITTLE SLOW AT 20Z! 17Z HRRR LOOKS SLOW AND LIGHT IN SW VA BUT EVEN
IT SPREADS QPF INTO S DE BY 03Z!
FGEN ON THE 12Z GFS LOOKS DECENT IN MID ATLC STATES S AND SE OF PHL
TONIGHT.
INITIALLY RAIN ONSET LATE THIS AFTN IN FAR SW DEL BUT COLUMN WET
BULBING DURING HEAVIER PCPN TONIGHT SHOULD PERMIT A CHG TO MIXED OR
ALL SNOW FOR A TIME WHERE IT HEAVIEST...ESP FAR S DE. EXCT DENDRITIC
GROWTH EARLY ON WITH UP TO 20MB LIFT IN THE SATURATED IDEAL DENDRITE
GROWTH ZONE BUT ALAS...BL TOO WARM IN S DE ON THE EARLY SIDE OF THE
PCPN EVENT.
STILL WONT BE SURPRISED AT ISOLATED .5 INCH SNOW ACC IN S DE BETWEEN
03Z-08Z. SNOW TOOLS OFFER .2.
BASED ON HOW DRY THE AIRMASS LOOKS TO BE...NORTH OF A KILG-KACY LINE
THE FORECAST WILL STILL BE DRY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
SATURDAY...MIXED SUN AND CLOUDS WITH AN INCREASINGLY GUSTY NW WIND
TO 20 OR 25 MPH SEASONABLY COOL TEMPS AS HIGH PRES SLOWLY EDGES INTO
THE REGION. DECENT LOW LVL LAPSE RATES FOR MOMENTUM TRANSFER...NOT
THAT MUCH WIND IN THE COLUMN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THIS FCST PERIOD STARTS OUT WITH AN UPPER TROF OVER THE EASTERN US
BUT THE TROF AXIS SHIFTS OFFSHORE BY SUNDAY NIGHT. A SHRTWV DIGGING
SEWD FROM THE WERN GRTLKS ON SUNDAY WILL BRING SOME CLOUDINESS BUT
DOESN`T HAVE ENOUGH MOISTURE TO WORK WITH TO CAUSE ANY SGFNT PRECIP.
THE COLDEST TEMPS...JUST SLIGHTLY BELOW NORMAL...WILL BE ON SUNDAY.
THEN WARMER AIR ADVECTS IN FROM WEST FOR MONDAY.
CONDITIONS SHOULD BE DRY FOR EARLY NEXT WEEK, BUT THEN POPS INCREASE
TOWARD MID-WEEK AS THE UPPER LOW NOW OVER SOCAL IS KICKED OUT AND
THE ASSOCD TROF MOVES INTO THE ERN U.S. THE 12Z RUNS OF THE GFS AND
ECMWF ARE ACTUALLY IN RATHER GOOD AGREEMENT ON THE TIMING OF THIS
SYSTEM MOVG ACROSS THE MID-ATLANTIC ON WED. WE HAVE SLGT CHC POPS
FOR TUES AS A COLD FRONT PUSHES S ACROSS THE ARRE AND THEN STALL.
HWVR...THE BEST LIKELIHOOD IS TUES NIGHT INTO WED AS SFC LOW PRES
TRACKS FROM THE MID MISS VLY NEWD INTO THE LOWER GRTLKS. TEMPS
SHOULD BE WARM ENOUGH DURG THIS TIME FOR ALL RAIN...EXCEPT PERHAPS
SOME MIXED PRECIP AT THE BEGINNING OR END OVER NEPA/NWNJ.
THE GFS AND ECMWF DIFFER CONSIDERABLE ON THE SYSTEM WHICH COULD
AFFECT US LATE NEXT WEEK...WITH THE ECMWF KEEPING MOST PRECIP AWAY
TO OUR SOUTH. WE FOLLOW THE HPC GUIDANCE FOR FRIDAY WHICH HAS CHC
POPS OVER OUR AREA. TEMPS AGAIN LOOK TOO WARM FOR SNOW WITH A
CONTINUING PATTERN OF ABOVE NORMAL WARMTH.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REMAINDER OF THIS AFTERNOON...VFR WITH CIGS AOA 12000 FT. TPHL VWP
HAS A NICE LOOK TO THE LOWERING CIRRUS DECK.
GUSTY NW WINDS GUSTY TO LESS THAN 18 KTS AND DIMINISHING FURTHER
THIS AFTN.
FOR TONIGHT...VFR CIGS AOA 5000 FT. LIGHT MOSTLY NW WIND.
OVER PHL...IT SHOULD BE SNOWING DOWN TO ABOUT 3000 OR 4000 FT BEFORE
EVAPORATING /VWP AT TPHL SHOULD BE HELPFUL/. KILG LOW PROBABILITY MAY
SEE AN HR OF RAIN OR R/S 03Z-05Z TIME FRAME?
OTRW...S DEL SHOULD SEE SNOW ALOFT CHANGE TO RAIN OR MXD SNOW/RAIN AT
THE SFC BUT NOT IMPOSSIBLE TO SEE AN HR OF 1MI WET SNOW VCNTY KGED TWD
05Z?
SATURDAY...VFR. SCT-BKN CLDS AOA 5000 FT EXPECTED. NW WIND SHOULD
GRADUALLY INCREASE WITH GUSTS TO 20 KTS.
OUTLOOK...
MAINLY VFR FLYING CONDITIONS EXPECTED SATUDAY NIGHT THROUGH
TUESDAY. CONDS WILL LIKELY BECOME WORSE TUESDAY NIGHT INTO
WEDNESDAY AS A LOW PRESSURE SYSTEM BRINGS RAIN INTO THE AREA.
&&
.MARINE...
SCA FOR DE ATLC WATERS EXTENDED TIL 6P. OTRW NO HEADLINES THRU AT
LEAST 18Z SAT.
A WEAK SURFACE LOW WILL PASS WELL SOUTH OF THE WATERS TONIGHT.
THE GRADIENT BEHIND THE LOW WILL NOT INCREASE UNTIL LATE TONIGHT.
NW WINDS ON SATURDAY MAY INCREASE TO SCA CRITERIA...ESP DE WATERS
AND ESP SAT AFTN...BUT FOR NOW MULTI MODEL TOOLS DO NOT OFFER MUCH
SUPPORT FOR AN SCA.
OUTLOOK...
NW WINDS SATURDAY NIGHT WILL DIMINISH AS HIGH PRES MOVES OVER THE
AREA...THEN WILL BECOME SW AND INCREASE ON MONDAY AS THE HIGH
MOVES OFFSHORE. SCA CONDS ARE POSSIBLE AROUND DTHIS TIME.
A FRONTAL SYSTEM WILL CROSS THE AREA TUESDAY BUT ASSOCD WINDS
SHOULD BE RELATIVELY LIGHT. WINDS SHOULD INCR AGAIN FROM THE SW
AND THEN SHIFT TO NW WED NIGHT AS LOW PRES AND ASSOCD CDFNT MOVE
ACROSS THE AERA. SCA CONDS ARE AGAIN POSSIBLE AT THIS TIME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ454-
455.
&&
$$
SYNOPSIS...AMC
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...AMC
AVIATION...DRAG
MARINE...AMC/DRAG
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
314 PM CST FRI DEC 16 2011
.SYNOPSIS...
12Z UA ANALYSIS HAS A SHORTWAVE ACROSS THE DAKOTAS WITH AN 850MB
ARCTIC FRONT FROM CENTRAL MINNESOTA INTO UPPER MICHIGAN. A RIDGE
EXTENDED FROM MINNESOTA INTO WEST TEXAS. SATELLITE AND RADAR TRENDS
THROUGH MID AFTERNOON SHOW LOW CLOUDS ACROSS PARTS OF THE DAKOTAS
INTO MINNESOTA WITH MID AND HIGH CLOUDS FROM NEBRASKA INTO
WISCONSIN. SOME LIGHT SNOW WAS OCCURRING IN WESTERN MINNESOTA WHERE
THE STRONGEST WAA WAS OCCURRING.
18Z SFC ANALYSIS HAS A WEAK CLIPPER SYSTEM LOW AT KMHE WITH A WARM
FRONT INTO NORTHWEST IOWA. A COLD FRONT EXTENDED FROM THE LOW IN
CENTRAL AND WESTERN NEBRASKA WHILE A TROF RAN FROM THE LOW INTO
SOUTHEAST COLORADO. DEW POINTS WERE IN THE TEENS AND 20S ACROSS MUCH
OF THE MIDWEST WITH 30 AND HIGHER DEW POINTS FROM THE SOUTHERN
PLAINS INTO THE DEEP SOUTH.
&&
.SHORT TERM...TONIGHT AND SATURDAY...
A WEAK CLIPPER SYSTEM WILL MOVE ACROSS THE AREA TONIGHT AND VERY
EARLY SATURDAY. THIS SYSTEM WILL BRING SOME SNOW TO ROUGHLY THE
NORTHERN QUARTER OF THE CWFA.
BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS THIS
SNOW EVENT WILL ONLY LAST ABOUT 6 TO POSSIBLY 8 HOURS ONCE IT BEGINS.
NOW...ALL MODELS INITIALIZED TOO MOIST WITH MOISTURE IN THE NORTHERN
PLAINS THIS MORNING. THAT COMBINED WITH THE VERY DRY ATMOSPHERE OVER
THE AREA WILL RESULT IN LOWER SNOW AMOUNTS. THE RUC HAS BEEN VERY
USEFUL SO FAR TODAY DEPICTING WHAT HAS BEEN HAPPENING ON THE 280K
CONDENSATION PRESSURE DEFICIT LAYER WHEN COMBINED WITH
FRONTOGENETICAL FORCING AND F VECTOR CONVERGENCE.
USING THE RUC AS A TREND...THE EARLY EVENING HOURS SHOULD REMAIN
DRY. BETWEEN 03Z AND 06Z FLURRIES OR POSSIBLY SOME VERY LIGHT SNOW
SHOULD MOVE IN OR DEVELOP NORTH OF A KVTI TO KSQI LINE. THE MOST
FAVORED AREA WOULD BE RIGHT ALONG AND NORTH OF HWY 20. HOWEVER...
FCST SOUNDINGS FROM THE RUC AT KDBQ STILL SHOW CONSIDERABLE AMOUNTS
OF DRY AIR BELOW 800MB SO PRECIPITATION CHANCES ARE STILL IN
QUESTION PRIOR TO MIDNIGHT.
AFTER MIDNIGHT THE MAIN VORT MAX MOVES THROUGH THE AREA. FROM JUST
BEFORE MIDNIGHT TO ROUGHLY 10Z WILL BE THE MOST LIKELY TIME FOR SNOW
TO OCCUR. AREAS NORTH OF A KALO TO KRPJ LINE SHOULD SEE -SN WITH
AREAS NORTH OF A KIIB TO KDKB LINE...OR EAST OF MANCHESTER ON THE
HIGHWAY 20 CORRIDOR...HAVING THE BEST CHANCE AT ANY ACCUMULATION.
AMOUNTS WILL BE LIGHT AND SHOULD BE NO MORE THAN 0.5 INCHES. AREAS
IMMEDIATELY NORTH OF THE CWFA MAY SEE AMOUNTS APPROACHING AN INCH.
SATURDAY...SOME LINGERING FLURRIES MAY OCCUR THROUGH SUNRISE IN THE
FAR NORTHEAST PART OF THE CWFA. OTHERWISE...DRY CONDITIONS WITH A
DECREASE IN CLOUDS SHOULD BE SEEN THROUGH THE DAY. TEMPERATURES
SHOULD BE AROUND OR A LITTLE ABOVE NORMAL.
..08..
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
SATURDAY NIGHT THROUGH MONDAY...OUR CWA WILL SPEND ANOTHER FEW DAYS
WELL ABOVE NORMAL...WITH TEMPERATURES MUCH MORE REPRESENTATIVE OF
LATE FALL VS MID DECEMBER. HIGHS SUNDAY AND MONDAY IN THE LOWER TO
UPPER 40S LOOK TO BE A STRONG BET...WHILE OVERNIGHT LIGHTS SATURDAY
NIGHT ONLY DIPS TO THE MID 20S AND SUNDAY NIGHT MAY HOLD IN THE
UPPER 30S TO LOWER 40S PENDING CLOUD COVER. WE WILL GO WITH LOWER TO
MID 30S BANKING ON SOME POTENTIAL CLEAR SKIES FOR NOW.
AFTER THE QUIET MILD WEATHER...OUR ATTENTION TURNS TO THE FORECAST
PROBLEMATIC STORM SYSTEM FOR MONDAY AND TUESDAY. MODELS ARE SHIFTING
THIS LOW FARTHER NORTH AGAIN. THIS IS NOT DUE TO SOME SORT OF
CONVECTIVE FEEDBACK OR ANYTHING...BUT RATHER THE INITIALIZATION OF A
STRONG SHORT WAVE OVER THE CENTRAL PACIFIC OCEAN. THE LATITUDE OF
THIS SHORT WAVE AS SEEN ON WATER VAPOR IMAGERY...IS ABOUT 30 TO 35
NORTH...LONGITUDE 155 WEST. THIS PLACEMENT IS A BIT SOUTH OF GLOBAL
MODELS AS OF 18Z. THE IMPACT WILL BE HUGE ON WHETHER THEY HANDLE
THIS WAVE CORRECTLY. OVER TOPPING THE WESTERN RIDGE WOULD RESULT IN
A SOUTHERN LOW TRACK...AND LITTLE OR NO QPF FROM THE STORM MONDAY
AND TUESDAY. A PHASED TRACK IS LIKELY IF THE LOW MAKES A ENTRY INTO
THE CANADIAN AND CONUS NEAR OR SOUTH OF 50 NORTH. THIS COULD BRING
THE SURFACE LOW AS FAR NORTH AS OVERHEAD...PRODUCING A SIGNIFICANT
RAIN EVENT. OUR POPS ARE IN THE CHANCE RANGE FOR MONDAY THROUGH
TUESDAY...WITH THE HIGHEST SOUTH. A TRANSITION FROM RAIN TO SNOW IS
FORECAST FOR MONDAY EVENING NORTH...TO TUESDAY MORNING SOUTH. WHILE
ACCUMULATION ARE POSSIBLE...THE COLD AIR IS LACKING TO THE STORM IN
A PHASED LOW FORECAST. THUS...WE WILL REMAIN VERY VAGUE ON
ACCUMULATION POTENTIAL AT THIS TIME ON PURPOSE.
WEDNESDAY THROUGH FRIDAY REMAINS NEAR OUR BLENDED MODEL FORECAST.
OVER ALL...ANOTHER LARGE TROUGH SHOULD APPROACH THE MIDWEST
THURSDAY...RESULTING IN A CHANCE FOR SNOW...AND POSSIBLY RAIN SNOW
MIX.
..ERVIN..
&&
.AVIATION...
VFR WX IS EXPECTED THROUGH 06Z/17. A CLIPPER TYPE STORM SYSTEM WILL
MOVE THROUGH THE WESTERN GREAT LAKES AFT 06Z/17. KCID/KMLI/KBRL ARE
EXPECTED TO REMAIN VFR THROUGH 00Z/18. KDBQ SHOULD REMAIN VFR WITH
-SN. THERE IS A POSSIBILITY OF A BRIEF PERIOD OF 3-5SM AND 3KFT AGL
CIGS AT KDBQ IN THE 04Z-09Z/17 TIME FRAME.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1147 AM CST FRI DEC 16 2011
.AVIATION...
VFR WX WILL BE SEEN THROUGH 03Z/17. AFT 03Z/17 A CLIPPER TYPE
STORM SYSTEM WILL MOVE INTO THE AREA. KCID/KMLI/KBRL SHOULD
CONTINUE TO SEE VFR CONDITIONS. KDBQ IS EXPECTED TO REMAIN VFR
WITH -SN. THE SNOW AT KDBQ IS ONLY EXPECTED TO LAST ABOUT 6 HRS.
ALTHOUGH LOW...THERE IS A POSSIBILITY OF A BRIEF 3-5SM -SN AND
CIGS ARND 3KFT AGL AT KDBQ IN THE 04Z-10Z/17 TIME FRAME.
..08..
&&
.PREV DISCUSSION... /ISSUED 1028 AM CST FRI DEC 16 2011/
UPDATE...
AN UPDATE TO THE OVERALL FORECAST FOR TODAY WILL BE AVAILABLE SHORTLY.
BASED ON DATA THROUGH 15Z...MAX TEMPERATURES LOOK A LITTLE TOO
WARM FOR TODAY AND WERE LOWERED A FEW DEGREES. RUC TRENDS
INDICATE THE RETURN WAA DOES NOT DEVELOP UNTIL CLOSE TO MID
AFTERNOON IN THE WESTERN CWFA WHICH IS RIGHT AROUND MAX HEATING
FOR THIS TIME OF YEAR.
AS FOR TONIGHT...FURTHER EVALUATION IS NEEDED REGARDING
PRECIPITATION CHANCES. HOWEVER...CURRENT DATA IS PLACING SOME
DOUBT ON THE CHANCE FOR SNOW.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1028 AM CST FRI DEC 16 2011
.UPDATE...
AN UPDATE TO THE OVERALL FORECAST FOR TODAY WILL BE AVAILABLE SHORTLY.
BASED ON DATA THROUGH 15Z...MAX TEMPERATURES LOOK A LITTLE TOO
WARM FOR TODAY AND WERE LOWERED A FEW DEGREES. RUC TRENDS
INDICATE THE RETURN WAA DOES NOT DEVELOP UNTIL CLOSE TO MID
AFTERNOON IN THE WESTERN CWFA WHICH IS RIGHT AROUND MAX HEATING
FOR THIS TIME OF YEAR.
AS FOR TONIGHT...FURTHER EVALUATION IS NEEDED REGARDING
PRECIPITATION CHANCES. HOWEVER...CURRENT DATA IS PLACING SOME
DOUBT ON THE CHANCE FOR SNOW.
..08..
&&
.PREV DISCUSSION... /ISSUED 544 AM CST FRI DEC 16 2011/
AVIATION... /ISSUED 324 AM CST FRI DEC 16 2011/
HIGH PRESSURE WILL REMAIN OVER THE MIDWEST TODAY...RESULTING IN VFR
CONDITIONS AND LIGHT WINDS. AFTER 06Z TONIGHT...A WEAK WAVE WILL
BRING MVFR CLOUDS TO AREAS MAINLY ALONG AND NORTH OF I80 WITH A
CHANCE FOR LIGHT SNOW ACCUMULATIONS AND MVFR VISIBILITY
REDUCTIONS. THE LOWER ATMOSPHERE IS EXTREMELY DRY...AND THERE IS
SIGNIFICANT UNCERTAINTY IN WHETHER IT WILL BE ABLE TO SATURATE
ENOUGH TO ALLOW ANY SNOW TO CAUSE VISIBILITY REDUCTIONS. ..DMD..
PREV DISCUSSION... /ISSUED 324 AM CST FRI DEC 16 2011/
SYNOPSIS...
SPLIT FLOW DOMINATES THE LONG WAVE PATTERN...WITH A CUT OFF LOW OVER
THE BAJA PENINSULA WHILE THE NORTHERN STREAM PROVIDES AN ACTIVE
NORTHWEST FLOW PATTERN FOR THE UPPER MIDWEST. WATER VAPOR LOOP
SHOWS A SHORT WAVE LIFTING ACROSS OKLAHOMA IN THE SOUTHERN STREAM
AND ANOTHER DROPPING INTO EASTERN MONTANA IN THE NORTHERN STREAM. AT
THE SURFACE...AREA TEMPERATURES HAVE FALLEN INTO THE 20S WITH DEW
POINTS ANYWHERE FROM THE MID TEENS TO MID 20S. COLD ADVECTION
CONTINUES WITH TEMPS IN THE TEENS AND DEW POINTS IN THE LOWER TO MID
TEENS UPSTREAM IN NORTH CENTRAL IOWA. ..DMD..
SHORT TERM...TODAY AND TONIGHT...
MAIN FOCUS THIS MORNING IS ON POTENTIAL FOR LIGHT SNOW WITH TONIGHTS
SHORT WAVE. SATELLITE TRENDS SUGGEST MORE ORGANIZATION TO THE WAVE
THAN THE MODELS WOULD PERHAPS INITIALLY IMPLY. 00Z GFS AND ECMWF
RUNS BOTH INDICATE ENOUGH FORCING TO SUPPORT LOW POPS OVER EXTREME
NORTHEAST IOWA INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS. THE
00Z AND 06Z NAM RUNS ALSO PICK UP ON THE FRONTOGENETICAL FORCING BUT
ARE LESS OPTIMISTIC ABOUT MOISTURE. TIME-HEIGHT CROSS SECTIONS OF
ALL MODELS IN FACT SHOW THAT THE LIFT AND FORCING MAY BE EXITING THE
AREA BEFORE THE LOWER ATMOSPHERE HAS MUCH OPPORTUNITY TO SATURATE.
END RESULT IS THAT ONLY AREAS CLOSER TO MAXIMUM LIFT...THAT IS NEAR
THE TRI-STATE REGION NORTH OF THE QUAD CITIES...THERE IS A CHANCE FOR
A LIGHT ACCUMULATION. HOWEVER...DIFFICULTY IN OVERCOMING THE DRY
BOUNDARY LAYER AND SHORT DURATION OF FORCING WILL LIMIT AMOUNTS.
HAVE INTRODUCED LOW POPS FOR TONIGHT FOR THIS SCENARIO. ..DMD..
LONG TERM...SATURDAY THROUGH THURSDAY...
THE PERIOD WILL GET OFF TO A QUIET START...UNDER THE INFLUENCE OF
DRY BUT MILD FLATTENING NORTHWEST FLOW. FOR EARLY NEXT WEEK
THOUGH...UNCERTAINTY STILL REIGNS CONCERNING THE POTENTIAL FOR
RAIN AND/OR SNOW EVENT OVER THE AREA WITH MODELS STILL GIVING
DIFFERING SOLUTIONS ON THE INTERACTION OF THE EJECTING
SOUTHWESTERN U.S. CUTOFF LOW AND A NORTHERN STREAM S/W. FOR
MID/LATE WEEK THERE IS A CONCENSUS AMONG THE GFS/ECMWF THAT THE
WESTERN U.S. TROF WILL REDEVELOP.
FOR SATURDAY AND SUNDAY NIGHT...THE REGION WILL BE EMBEDDED IN NORTHWEST
FLOW BETWEEN A WESTERN U.S. RIDGE AND AN OHIO VALLEY/GREAT LAKES
TROF. A S/W TRACKING THROUGH THE WESTERN GREAT LAKES SHOULD BE FAR
ENOUGH EAST TO KEEP ANY SNOW WELL EAST OF THE CWFA SATURDAY
AFTERNOON AND EVENING. TEMPERATURES SHOULD REMAIN NEAR TO ABOVE
NORMAL FOR THE WEEKEND. SOME SUN ON SATURDAY SHOULD HELP BOOST
READINGS IN THE MID 30S TO AROUND 40. FOR SUNDAY NIGHT
TEMPERATURES SHOULD BE ABLE TO RADIATE OUT WITH A SURFACE RIDGE
MOVING THROUGH THE AREA...SO SKEWED LOWS TOWARD THE COLDER
GUIDANCE. WITH THE RIDGE EAST OF THE AREA SUNDAY...RETURN FLOW
SETS UP SO TEMPS ARE EXPECTED TO RECOVER INTO THE LOW TO MID 40S.
INCREASING SOUTHWEST FLOW AHEAD OF COLD FRONT DROPPING INTO
NORTHWEST IOWA SUNDAY NIGHT...AS WELL INCREASING SURFACE DEW POINTS
AND CLOUDS WILL KEEP TEMPERATURES FROM FALLING MUCH BY MONDAY
MORNING...SO KEPT MINS IN THE LOW TO MID 30S.
FOR MONDAY THROUGH TUESDAY NIGHT THE MODELS ARE STILL OFFERING
DIFFERENT SOLUTIONS CONCERNING THE EJECTING SOUTHWEST LOW AND HOW
IT IS INFLUENCED BY A NORTHERN STREAM S/W. THE 00Z GFS IS STILL
LOCKED INTO THE MORE NORTHERN SOLUTION WITH THE EJECTING UPPER
LOW...WHICH GIVES THE AREA ANOTHER MODERATE PRECIPITATION EVENT.
THE 12Z AND 00Z ECMWF ARE STILL HOLDING ON TO A MORE SOUTHERN
TRACK OF THE UPPER LOW...WHICH KEEPS A LEAST THE NORTHER HALF OF
THE AREA DRY. THE ONLY CHANGES TO THE PREVIOUS FORECAST THEN
CONCERNING POPS AND THE DIFFERING SOLUTIONS WAS TO INCREASE POPS
TO HIGH CHANCE IN THE SOUTH WITH THE LATEST ECMWF MOVING THE
NORTHERN EDGE OF IT/S PRECIPITATION SHIELD A LITTLE FURTHER NORTH
TUESDAY AND LOWERING POPS TO SLIGHT CHANCE MONDAY AND MONDAY NIGHT
IN THE NORTH WITH THE GFS MOVING ITS NORTHERN EDGE A LITTLE MORE
SOUTH THAN THE PREVIOUS RUNS. PRECIPITATION TYPE IS STILL HARD TO
PIN DOWN WITH THE DIFFERING SOLUTIONS SO MAINTAINED THE RAIN OR
RAIN/SNOW WORDING AS THE SYSTEM APPROACHES MONDAY THEN SNOW
SPREADING SOUTHEAST MONDAY NIGHT AND TUESDAY WITH SYSTEM PULLING
AWAY FROM THE REGION.
BOTH THE GFS/ECMWF SHOW ANOTHER UPPER TROF DEVELOPING OVER THE
WESTERN U.S. BY THE END OF THE WEEK. EXPECT DRY WEATHER DURING THE
TRANSITION WITH INCREASING SOUTHWESTERLY FLOW SUPPORTING ABOVE
NORMAL TEMPERATURES. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
227 PM MST FRI DEC 16 2011
.DISCUSSION...
227 PM MST FRI DEC 16 2011
MAIN FORECAST PROBLEM WILL BE STORM FOR THE BEGINNING OF NEXT WEEK
WITH SECONDARY PROBLEMS OF HOW MUCH TO WARM IT UP BEFORE THIS NEXT
UPPER LOW FOLLOWED BY WHAT KIND OF WEATHER THE NEXT COMPLICATED UPPER
TROUGH/S WILL BRING TO THE AREA THE END OF NEXT WEEK. SATELLITE
SHOWING AN AMPLIFIED/AMPLIFYING PATTERN FROM THE PACIFIC INTO NORTH
AMERICA. DUE TO DEEPENING TROUGH OVER THE WESTERN PACIFIC...SOUTHERN
END OF EASTERN PACIFIC TROUGH IS DEEPENING AND CAUSING THE WESTERN
RIDGE TO BUILD. THIS AND HEIGHT FALL ANALYSIS SHOWS UPPER LOW OVER
BAJA SINKING SOUTH AND WEST. THIS IS PART OF SPLIT FLOW/MEAN TROUGH
THAT EXISTS OVER MOST OF THE REST OF THE COUNTRY.
IN REGARDS TO THE JET OVER THE NORTHEAST PACIFIC AND ROUNDING OVER
THE TOP OF THE RIDGE...THE MODELS LOOK UNDERDONE ON SPEEDS. ON THE
SEGMENT THAT EXTENDS FROM MONTANA TO THE NORTHWEST OF THE UPPER LOW
THE MODELS TENDED TO BE SLIGHTLY UNDERDONE AND TOO FAR EAST AND
SOUTH WITH THE SEGMENT. THE NAM WAS DOING THE BEST FOLLOWED BY THE
UKMET AND THE CANADIAN. SAME THING AT MID LEVELS WITH THE NAM DOING
SLIGHTLY BETTER THAN THE CANADIAN AND UKMET. AT THE SURFACE...THE
ECMWF WAS DOING SLIGHTLY BETTER THAN THE NAM. ON THE LOW LEVEL
THERMAL FIELD THE NAM AND GFS WERE DOING SLIGHTLY BETTER THAN THE
REMAINING OUTPUT.
TONIGHT...CURRENT SURFACE OBSERVATIONS SHOW A SURFACE TROUGH MOVING
EAST ACROSS THE TRI-STATE AREA. WINDS HAVE REMAINED LIGHT TO
BREEZY...BUT A FEW GUSTS HAVE APPROACHED 25 MPH AHEAD AND BEHIND THE
TROUGH. RUC UPPER AIR ANALYSIS SHOWS AN UPPER LEVEL TROUGH
FOLLOWING THE SURFACE FEATURE...AND SATELLITE IMAGERY CONTINUES TO
SHOW A FEW MID AND HIGH CLOUDS ON EITHER SIDE OF THE UPPER LEVEL
TROUGH. FURTHER WEST THE CLOSED LOW REMAINS POSITIONED OVER THE
BAJA PENINSULA AND HAS BEEN SLOWLY RETROGRADING TO THE WEST THROUGH
THE DAY.
NORTHWEST WINDS WILL GRADUALLY TURN TO THE WEST DURING THE EVENING...
AS A SURFACE RIDGE OF HIGH PRESSURE MOVES ACROSS THE TRI-STATE AREA
BEHIND THE SURFACE TROUGH. RELATIVE HUMIDITY VALUES WILL BE NEAR 100
PERCENT OVER THE SNOW FIELD FOR THE MCCOOK AND OBERLIN AREA. HOWEVER
THE LIGHT WEST WINDS AND DRY AIR ABOVE THE SURFACE WOULD SUPPORT NO
FOG FORMING. OTHERWISE LOWS WILL BE SIMILAR TO LAST NIGHT.
SATURDAY/SATURDAY NIGHT...AREA REMAINS UNDER SUBSIDENCE AND
INFLUENCE FROM THE MID/UPPER RIDGE. WILL BE DOWNSLOPE WINDS BUT
MOSTLY LIGHT. DID WARM UP TEMPERATURES BUT POTENTIAL IS THERE TO BE
WARMER THAN WHAT I HAVE. DURING THE NIGHT DOWNSLOPE WINDS ARE IN
PLACE AND CLOUDS DO INCREASE A LITTLE.
SUNDAY...MAIN JET IS STILL FAR AWAY FROM THE AREA. DUE TO THE UPPER
LOW STILL BEING VERY FAR AWAY...MID LEVEL RIDGING AND DRYING WILL
BE IN PLACE. BY THIS TIME...WHATEVER SNOW IS HERE NOW SHOULD NOT BE
A FACTOR IN MAXES. MODELS DIFFER ON THE AMOUNT OF WARMUP WITH THE
ECMWF SHOWING THE MOST. THERE IS WEAK DOWNSLOPING OF THE WINDS WITH
THE MODELS SHOWING LITTLE IF ANY MIXING. ALSO BECAUSE OF THE
MID/UPPER LEVEL RIDGING IN PLACE...IT LOOKS LIKE THERE WILL BE A LOT
OF SUNSHINE. SO IT LOOKS LIKE MODELS ARE UNDERDOING THE WARMING AT
THIS TIME. RAISED MAXES BUT TEMPERED IT SOMEWHAT BASED ON
COLLABORATION AND THRESHOLDS. HOWEVER...THE POTENTIAL FOR BEING
MUCH WARMER THAN WHAT IS CURRENTLY IN THERE IS PRETTY HIGH. IF THE
MIXING GETS CLOSER TO 700 MB...TEMPERATURES COULD SORE INTO THE 60S
BUT I DEFINITELY DID NOT GO THAT FAR.
SUNDAY NIGHT/MONDAY...WEAKER LEFT FRONT QUADRANT OF THE SOUTHERN JET
LOOKS TO START AFFECT THE SOUTHEAST PORTION OF THE AREA LATE IN THE
NIGHT. OF NOTE HIGHER JET SPEEDS ARE STILL BEHIND INCOMING SYSTEM
AS OF 12Z MONDAY. MOST OF THE DETERMINISTIC AND ENSEMBLE DATA SHOW
THE NEXT SYSTEM COMING FURTHER SOUTH AND SLOWER WITH STILL SOMEWHAT
OF A SPREAD. THE NAM AND GEFS MEAN ARE THE FASTEST AND FURTHEST
NORTH WITH THE CANADIAN AND ECMWF FURTHEST SOUTH. IT IS STARTING TO
LOOK LIKE FURTHER SOUTH IS APPEARING MORE LIKELY. THAT SAID WITH
LITTLE IF ANY LIFT AND SOUNDINGS SHOWING AIR MASS STILL DRY...THE
DRY FORECAST FOR SUNDAY NIGHT STILL LOOKS GOOD.
LEFT FRONT QUADRANT OF THE JET AFFECTS MAINLY SOUTHEAST HALF OF THE
AREA EARLY IN THE DAY. MOST OF THE FORCING STILL LOOKS TO BE OVER
TH SOUTHERN PORTION OF THE AREA. IF NAM/GEFS RIGHT...PRECIPITATION
CHANCE WILL BE GREATER. IF ECMWF AND ESPECIALLY THE CANADIAN IS
RIGHT...PRECIPITATION WILL BE LOWER. SINCE THERE IS STILL A LOT OF
MODEL SPREAD AND CURRENT MODEL DATA SUPPORTS THE ONGOING FORECAST...
DID NOT CHANGE MONDAYS PRECIPITATION FORECAST. IT WILL DEFINITELY
WILL BE WINDY AND COLDER ON MONDAY. IF CURRENT TRENDS CONTINUE IT IS
POSSIBLE THAT MAXES WILL NEED TO BE LOWERED MORE.
MONDAY NIGHT THROUGH FRIDAY...SPREAD ON THE DETERMINISTIC AND
ENSEMBLE OUTPUT EARLY ON THROUGH TUESDAY IS PRETTY LARGE. THINKING
THAT THE SYSTEM IS LOOKING TO BE FURTHER SOUTH...PRECIPITATION
SHOULD BE DONE OR MOSTLY DONE BY 12Z TUESDAY. MODERATION OF
TEMPERATURES THEN OCCUR AS THE WESTERN TROUGH RELOADS AND MODELS TRY
TO DECIDE WHAT TO DO WITH THE NEXT SYSTEM. SPREAD IN DETERMINISTIC
AND ENSEMBLE OUTPUT CONTINUES WITH THIS NEXT SET OF STORM SYSTEMS AS
WELL.
ON THURSDAY ALL THE MODELS DO BRING A MID LEVEL TROUGH THROUGH
BUT DIFFER ON THE STRENGTH AND SPEED. IF ECMWF WERE TO VERIFY THEN
PRECIPITATION MAY NEED TO BE EXPANDED FROM WHERE IT IS AT NOW. MODELS
SHOW A FRONT MOVE THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY BUT
DIFFER ON TIME. DUE TO ITS HANDLING OF THE SYSTEM AT MID LEVELS...
THE ECMWF IS MORE AGGRESSIVE WITH THE COOLING...AND LOOKS LIKE IT
IS THE BEST SOLUTION...TEMPERATURES WILL BE COOLED MORE FROM THEY
ARE AT NOW. FRIDAY LOOKS DRY AT THIS TIME BUT WITH MODEL SPREAD
THAT COULD CHANGE. COLDER WORKS ITS WAY INTO THE AREA...COLD MAXES
IN GRIDS LOOK GOOD.
THANKS TO ALL THAT COLLABORATED.
BULLER
&&
.AVIATION...
1020 AM MST FRI DEC 16 2011
VFR CONDITIONS CAN BE EXPECTED FOR THE 12Z TAFS. CURRENT SURFACE
OBSERVATIONS SHOW A SURFACE TROUGH MOVING ACROSS NEBRASKA AND
NORTHWEST KANSAS. UPPER AIR ANALYSIS SHOWS AN UPPER LEVEL TROUGH
FOLLOWING THE SURFACE FEATURE. AS THE TROUGH MOVES THROUGH THE WINDS
HAVE QUICKLY SHIFTED FROM THE WEST TO THE NORTH OR NORTHWEST. WITH
LITTLE MOISTURE TO WORK WITH...A FEW MID AND HIGH CLOUDS CAN BE
EXPECTED AS THE TROUGH MOVES THROUGH. DURING THE EVENING HOURS
WINDS WILL TURN BACK TO THE WEST AS A SURFACE RIDGE OF HIGH
PRESSURE BUILDS INTO WESTERN KANSAS. OVERNIGHT TEMPERATURES WILL
APPROACH THE DEW POINT. AM NOT CONFIDENT ENOUGH FOG WILL FORM TO
PLACE IT IN THE TAFS AS TEMPERATURE AND DEW POINT LOOK TO DROP IN
UNISON DURING THE NIGHT.
JTL
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1028 AM MST FRI DEC 16 2011
.SHORT TERM (TODAY-SUNDAY)...
233 AM MST FRI DEC 16 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW SPLIT-FLOW PATTERN
ACROSS THE EASTERN CONUS...WITH CUTOFF LOW OVER THE BAJA PENINSULA.
CWA CURRENTLY BETWEEN SHORTWAVE TROUGHS...WITH LARGE SCALE
SUBSIDENCE CURRENTLY IN PLACE.
EARLY THIS MORNING...FOG CHANCES HAVE DIMINISHED ACROSS EASTERN
COLORADO. 06Z NAM WOULD KEEP AND FOG/STRATUS SW OF CWA. LATEST RUC
DOESNT BRING BL RH VALUES ABOVE 75% ANYWHERE IN EASTERN COLORADO. I
COULDNT COMPLETELY RULE OUT ISOLATED POCKETS OF FOG NEAR SUNRISE IN
NEAR EXTREME SW PART OF CWA...BUT CONFIDENCE IS TOO LOW TO KEEP
MENTION IN FORECAST FOR NOW.
TODAY-SUNDAY NIGHT...SHORTWAVE TROUGH CURRENTLY OVER SE WYOMING WILL
SWING ACROSS THE CWA TODAY. WITH DEEP DRY LAYER IN PLACE...WILL
ONLY SEE PERIOD OF MID-HIGH CLOUDS. SHORTWAVE RIDGE BUILDS OVER CWA
SAT AND SUNDAY...WITH WARM AND DRY CONDITIONS EXPECTED. HIGHS IN LOW
50S ACROSS MOST SOUTH AND WESTERN LOCATIONS SEEMS REASONABLE SAT. I
MAY STILL BE GIVING LINGERING SNOW COVER TOO MUCH CREDIT ACROSS THE NE
PART OF CWA ON SAT AFTER ANOTHER DAY OF MELTING TODAY. GUIDANCE
SHOWING GOOD WAA SUNDAY AHEAD OF CUTOFF LOW AS IT BEGINS TO MOVE
TOWARDS FOUR CORNERS REGION. H85 TEMPS AROUND 10C ACROSS CWA PROGGED
BY MOST GUIDANCE...AND NO LINGERING IMPACTS FROM SNOW COVER
EXPECTED. I CURRENTLY HAVE MID-UPPER 50S IN THE SOUTH AND LOWER 50S
IN THE NORTH WHICH STILL MAY END UP BEING TOO LOW.
DR
.LONG TERM (MONDAY-THURSDAY)...
233 AM MST FRI DEC 16 2011
THE GFS AND NAM ARE IN BETTER AGREEMENT AND MORE PROGRESSIVE THAN
IN THE ECMWF IN BRINGING THE UPPER LOW CENTER INTO THE CENTRAL
TEXAS PANHANDLE REGION BY MID DAY MONDAY. THE ECMWF IS DELAYED
SEVERAL HOURS AND DOESN`T BRING IT INTO A SIMILAR POSITION UNTIL
MONDAY EVENING. THE LOW CENTER IS AS DEEP ON THE ECMWF AS THE
GFS...BUT THE TROUGH THE LOW IN PHASING INTO...AND THE SUBSEQUENT
SECONDARY TROUGH AXIS ACTING AS THE KICKER...ISN`T AS DEEP ON THE
ECMWF. THEREFORE...WHILE CONFIDENCE IS INCREASING FOR MONDAY`S
SOLUTION...CONFIDENCE DIMINISHES THROUGH THE WEEK.
CURRENTLY...IT APPEARS THE SURFACE LOW CENTER EMERGES IN EASTERN NEW
MEXICO AND TRACKS THROUGH THE TEXAS PANHANDLE REGION ON MONDAY WITH
PRECIPITATION SPREADING NORTHWARD INTO THE FORECAST AREA THROUGH THE
DAY AND THEN TAPERING OFF FROM WEST TO EAST AS THE LOW CONTINUES TO
THE EAST NORTHEAST. EXPECT GOOD COLD AIR ADVECTION DURING THE DAY
WITH SOME OVERRUNNING EARLY MONDAY MORNING FOR A POSSIBLE RAIN AND
SNOW MIX THAT CHANGES OVER TO ALL SNOW BY LATE IN THE DAY.
CURRENTLY...ONLY 1-2 INCHES OF SNOW AT THE MOST IS EXPECTED
PRIMARILY ACROSS THE SOUTHEAST PORTION OF THE FORECAST AREA. EXPECT
CLEARING OVERNIGHT MONDAY NIGHT AS THE SYSTEM MOVES FAIRLY QUICKLY
OFF TO THE EAST.
TEMPERATURES WILL WARM SOME TUESDAY AND WEDNESDAY AS A SHORT WAVE
RIDGE ALOFT MOVES ACROSS THE REGION WITH TEMPERATURES EXPECTED TO
COOL AGAIN LATE IN THE WEEK AS THE JET SAGS SOUTH AND ANOTHER TROUGH
TRANSITIONS THE CENTRAL HIGH PLAINS REGION THURSDAY AND FRIDAY.
LOCKHART
&&
.AVIATION...
1020 AM MST FRI DEC 16 2011
VFR CONDITIONS CAN BE EXPECTED FOR THE 12Z TAFS. CURRENT SURFACE
OBSERVATIONS SHOW A SURFACE TROUGH MOVING ACROSS NEBRASKA AND NORTHWEST
KANSAS. UPPER AIR ANALYSIS SHOWS AN UPPER LEVEL TROUGH FOLLOWING
THE SURFACE FEATURE. AS THE TROUGH MOVES THROUGH THE WINDS HAVE
QUICKLY SHIFTED FROM THE WEST TO THE NORTH OR NORTHWEST. WITH
LITTLE MOISTURE TO WORK WITH...A FEW MID AND HIGH CLOUDS CAN BE
EXPECTED AS THE TROUGH MOVES THROUGH. DURING THE EVENING HOURS
WINDS WILL TURN BACK TO THE WEST AS A SURFACE RIDGE OF HIGH
PRESSURE BUILDS INTO WESTERN KANSAS. OVERNIGHT TEMPERATURES WILL
APPROACH THE DEW POINT. AM NOT CONFIDENT ENOUGH FOG WILL FORM TO
PLACE IT IN THE TAFS AS TEMPERATURE AND DEW POINT LOOK TO DROP IN
UNISON DURING THE NIGHT.
JTL
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1231 PM EST FRI DEC 16 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RIDGING INTO WRN CANADA
AND A DOWNSTREAM TROF EXTENDING S INTO THE NRN PLAINS/GREAT LAKES.
FLOW IS SPLIT WITH A WEAKER SRN STREAM FEATURING A MID LEVEL LOW
OVER SRN CA AND A WEAK SHORTWAVE OVER THE SRN PLAINS. A POTENT
SHORTWAVE PASSED THRU THE UPPER GREAT LAKES LAST EVENING...BRINGING
A BOUT OF STRONG WINDS OVER LAKE SUPERIOR AND LAKE ENHANCED SNOW IN
ITS WAKE. WINDS GUSTED TO 58MPH AT GRAND MARAIS AND 61MPH AT
STANNARD ROCK. LES HAS NOTABLY DIMINISHED OVER THE LAST FEW HRS AS
FAST WNW FLOW IS PUSHING SYSTEMS ALONG QUICKLY. NEXT WEAK SHORTWAVE
TROF IS MOVING INTO THE DAKOTAS AND MANITOBA. A MORE IMPORTANT
SHORTWAVE IS TOPPING THE WRN CANADA RIDGE OVER NRN BRITISH COLUMBIA
AND THE SRN YUKON.
&&
.DISCUSSION...
WEATHER THRU THIS FCST PERIOD WILL BE DOMINATED BY A MEAN RIDGE OF
VARYING AMPLITUDE OVER WRN CANADA AND A DOWNSTREAM POLAR VORTEX IN
THE VCNTY OF NRN HUDSON BAY/BAFFIN ISLAND. END RESULT SHOULD BE
SEVERAL QUICK MOVING NRN STREAM SHORTWAVES WITH VERY LITTLE PCPN
OUTSIDE OF AREAS AFFECTED BY SOME LAKE EFFECT/LAKE ENHANCED SNOW
ASSOCIATED WITH PASSING WAVES. FLOW ALSO LOOKS TO REMAIN SPLIT WITH
SRN STREAM WAVES AND ASSOCIATED PCPN PASSING S OF UPPER MI.
OVERALL...IT WILL NOT BE AN ESPECIALLY WINTRY PATTERN HEADING TOWARD
THE LATTER PORTION OF DEC AS NORTHERLY POSITION OF POLAR VORTEX
LARGELY HOLDS ARCTIC AIR N OF THE AREA. ONLY BRIEF INTRUSIONS OF
COLDER AIR WILL OCCUR OVER THE NEXT 7 DAYS.
FOR TODAY...DESPITE 850MB TEMPS IN THE -14 TO -16C RANGE...ONGOING
LES WILL HAVE TO FIGHT DRY AIR/LOW INVERSION. 00Z KINL SOUNDING
SHOWED INVERSION BASED AROUND 875MB/4000FT MSL. NAM/GFS FCST
SOUNDINGS HAVE A GOOD HANDLE ON THIS. ALTHOUGH CONVECTION WILL BE
SHALLOW...THE DENDRITIC SNOW GROWTH TEMP ZONE WILL BE WITHIN THE
CONVECTIVE LAYER. SO...THERE SHOULD BE SOME LIGHT FLUFFY SNOW
ACCUMULATION TODAY OF AN INCH...MAYBE TWO...WHERE LES IS MORE
PERSISTENT. WEAK SHORTWAVE OVER THE DAKOTAS/MANITOBA WILL HAVE
LITTLE IMPACT ON LES THIS AFTN/EVENING AS WEAK QVECTOR DIVERGENCE
DOMINATES. GFS/NAM HAVE ALSO BACKED OFF ON DEEPENING OF MOISTURE
PROFILE WITH PASSING WAVE. LES AFFECTING NW/WNW FLOW FAVORED AREAS
TODAY WILL SHIFT TONIGHT AS WINDS BACK SW AHEAD OF STRONGER
SHORTWAVE (CURRENTLY OVER NRN BRITISH COLUMBIA/SRN YUKON) DROPPING
SE THRU SASKATCHEWAN/MANITOBA.
AS SHORTWAVE DROPS SE THRU THE UPPER GREAT LAKES SAT...HEALTHY DEEP
LAYER FORCING PER QVECTORS WILL OVERSPREAD THE AREA. COMBINED WITH
STEEP MIDLEVEL LAPSE RATES UPWARDS OF 7.5C/KM...WAVE MAY BE ABLE TO
SQUEEZE OUT A BRIEF PERIOD OF LIGHT SNOW AT MOST LOCATIONS. ANY
SYNOPTIC SNOW ACCUMULATION SHOULD BE UNDER AN INCH. 850MB TEMPS
AROUND -10C WILL SUPPORT SOME LAKE ENHANCEMENT OVER WRN UPPER MI AS
WINDS SHIFT FROM SW TO NW. A FEW INCHES OF SNOW CERTAINLY POSSIBLE
OVER THE NW SAT AFTN INTO EARLY SAT EVENING. BRIEF ENHANCEMENT WILL
SHIFT INTO AREAS E OF KMQT SAT EVENING AS WINDS SHIFT NW. THERE MAY
BE SOME LAKE ENHANCEMENT OFF NRN LAKE MICHIGAN INTO THE FAR ERN FCST
AREA SAT AFTN IN THE SW FLOW AHEAD OF THE SHORTWAVE. RIGHT NOW...IT
APPEARS WINDS WILL HAVE TOO MUCH A WRLY COMPONENT TO OFFER MUCH
ENHANCEMENT POTENTIAL FOR SCHOOLCRAFT/LUCE COUNTIES. NW FLOW LES
WILL RAPIDLY DIMINISH SAT NIGHT FROM W TO E AS AIRMASS QUICKLY DRIES
AND INVERSION CRASHES TO 4KFT OR LOWER.
WAA WILL BE UNDERWAY SUN AS NEXT SHORTWAVE MOVES ACROSS SCNTRL
CANADA. ALL GUIDANCE SHOW ASSOCIATED SFC LOW PASSING N OF UPPER MI
SUN NIGHT. WAA/ISENTROPIC ASCENT IS STRONG SUN WITH 40+KT WINDS
ORIENTED PERPENDICULAR TO TIGHTLY SPACED ISOBARS. HOWEVER..AIRMASS
IS VERY DRY AT THE LOWER LEVELS. AT THIS POINT...PLAN TO CARRY A DRY
FCST SUN/SUN NIGHT WITH ANY PCPN N OF UPPER MI. SHALLOW MOISTURE
DROPPING INTO THE AREA BEHIND COLD FRONT WITH 850MB TEMPS FALLING
PERHAPS TO AROUND -12C MAY SUPPORT SOME LIGHT LES/FLURRIES OFF LAKE
SUPERIOR MON INTO MON NIGHT.
TWO MORE SHORTWAVES WILL PASS ACROSS THE AREA DURING THE MIDDLE OF
NEXT WEEK...TUE AND THU. PCPN CHANCES APPEAR LIMITED...AND AIR MASS
MAY NOT EVEN BE COLD ENOUGH TO SUPPORT MUCH IF ANY LAKE EFFECT.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
NORTHWEST WINDS FLOWING ACROSS LAKE SUPERIOR WILL KEEP CHANCES OF
LAKE EFFECT SNOWS ACROSS MUCH OF UPPER MICHIGAN. OCCASIONAL FLURRIES
WITH MVFR CONDITIONS ARE IN FCST AT ALL SITES INTO THIS EVENING. BY
TONIGHT...JUST SOME MID CLOUDS WILL BE PUSHING ACROSS THE UPPER
LAKES. EXPECT VFR CONDITIONS AT ALL THE TAF SITES TONIGHT. CEILINGS
WILL BEGIN TO LOWER FROM WEST TO EAST STARTING SAT MORNING AHEAD OF
AN UPPER LEVEL DISTURBANCE...BUT SHOULD NOT FALL BELOW VFR LEVELS
UNTIL AFTER THE END OF THIS TAF PERIOD.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
STRONG GALE EVENT WITH EVEN SOME STORM FORCE GUSTS HAS WOUND DOWN.
WINDS BECOME LESS THAN 20 KTS THROUGH TONIGHT AS HIGH PRESSURE
RIDGE SETTLES ACROSS. LIGHT WINDS ARE BRIEF THOUGH AS STRONG AND
QUITE CHANGEABLE WINDS ARE THEN EXPECTED THROUGH EARLY NEXT WEEK.
SOUTHWEST WINDS INCREASE TO 30 KTS ON SATURDAY AS LOW PRESSURE
TROUGH APPROACHES. DESPITE WARM AIR ADVECTION AND HIGHER
STABILITY...STRONG PRESSURE FALLS NORTH OF LK SUPERIOR MAY LEAD TO
GALE FORCE GUSTS OVR CNTRL LK SUPERIOR BTWN KEWEENAW AND ISLE ROYALE
SATURDAY AFTERNOON AND EVENING. WINDS SHIFT NORTHWEST BEHIND TROUGH
BUT THE ARRIVAL OF YET ANOTHER TROUGH FM NORTHWEST ON SUNDAY LEADS
TO MORE STRONG SOUTHWEST WINDS SUNDAY AFTERNOON AND EVENING. GALES
APPEAR POSSIBLE OVR CNTRL LK SUPERIOR ONCE AGAIN. WINDS STAY BTWN
20-30 KTS FOR EARLY NEXT WEEK AS ANOTHER TROUGH IS FORECAST TO MOVE
ACROSS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...TITUS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1206 PM CST FRI DEC 16 2011
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
DECENT BUT NOT STRONG WARM ADVECTION PATTERN WITH SYSTEM OVER THE
DAKOTAS AND THERE HAVE BEEN A FEW OBSERVATIONS WITH VSBYS LESS
THAN 3SM. THE WARM ADVECTION PATTERN APPEARS TO BECOME A BIT MORE
BROAD AS IT SPREADS SOUTHEAST...BUT THE LATEST RUC DOES HOLD ON TO
A CENTER OF QG INSTANTANEOUS PRECIP RATE INTO WEST CENTRAL AND SOUTH
CENTRAL MINNESOTA DURING THE AFTERNOON. THE CHANCES OF MEASURABLE
SNOW ARE SLIM BUT THERE IS ENOUGH OF A SIGNAL TO INCLUDE A SMALL
AREA OF POPS ON A TRACK THROUGH THE ABOVE MENTIONED AREA...WITH
FLURRIES OVER A LARGER AREA. THIS FEATURED MAY STILL BE AFFECTING
SOUTH CENTRAL OR SOUTHEAST MINNESOTA THIS EVENING. A STRONGER WARM
ADVECTION PATTERN WITH ANOTHER WAVE DROPPING SOUTHEAST THROUGH
NORTHWEST ONTARIO INTO THE GREAT LAKES...MAY BRUSH NORTHWEST
WISCONSIN WITH LIGHT SNOW MID DAY ON SATURDAY.
THIS WILL SET UP MOST OF THE CWA IN THE WARM SECTOR SATURDAY NIGHT
AND SUNDAY. IT IT STILL LOOKS WARM...ALTHOUGH THE STRENGTH OF THE
850 MB TEMP ANOMALY IS NOT TOO EXTREME. IT SHOULD BE WARMER THAN
MOST OF THE STANDARD GUIDANCE BUT CLOSER TO THE ECMWF AND A FEW
OF THE BIAS CORRECTED VALUES. A DRY COLD FRONT IS THEN FORECAST TO
MOVE THROUGH LATE SUNDAY NIGHT WITH GUSTY WINDS FOR MONDAY. STILL
NO SIGNIFICANT CHANCE FOR PRECIP WITH THE SPLIT FLOW...WITH OUR
AREA JUST AFFECTED BY SYSTEMS MOVING ACROSS SOUTHERN CANADA IN
THE WEST TO NORTHWEST FLOW. THERE WILL BE ANOTHER CHANCE OF A
MILD DAY MID WEEK...AHEAD OF THE NEXT IN A SERIES FRONTS MOVING
ACROSS THE AREA. THERE MAY A CHANCE OF SOME INTERACTION WITH THE
SOUTHERN STREAM AFTER THE FRONT MOVES THOUGH MID WEEK. WE ONLY
HAVE A SMALL CHANCE OF SNOW OVER MAINLY THE SOUTHERN CWA ON
THURSDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
WEAK SHORTWAVE MOVING INTO MN LATE THIS MORNING IS SHAKING OUT
SOME SNOW SHOWERS. HAVE SEEN NUMEROUS 2-4SM OBS TO THE WEST
/INCLUDING AXN/ SO BEEFED UP SNOW MENTION AT MANY FIELDS. 850-700
MB RH/FGEN ON THE GFS HANDLING CURRENT SNOW WELL...SO USED IT FOR
MOVING SNOW ACROSS THE AREA TODAY. BASED ON THIS...SNOW SHOULD
MOVE DUE SE FROM ITS CURRENT LOCATION...GRAZING STC/RNH/EAU. BASED
ON WEBCAMS OUT WEST...COULD SEE A HALF INCH OF SNOW OUT OF
THIS...ESPECIALLY AT AXN/RWF. CIGS THROUGH THIS EVENING WILL ALSO
BOUNCE AROUND BETWEEN 020 AND 040...WITH MN TERMINALS BOUNCING IN
AND OUT OF MVFR CONDITIONS. LATE TONIGHT...ANOTHER WAVE WILL MOVE
INTO NRN MN...THEN INTO NRN WI SAT MORNING. SREF PROBS HAVE AN
AREA OF MVFR CIGS MOVING FORM NRN MN INTO CENTRAL WI WITH THIS
FEATURE. IN ADDITION...GFSLAMP AT RNH/EAU SHOW MVFR CIGS
RETURNING SATURDAY MORNING...SO ENDED THE WI TAFS WITH RESTRICTED
CIGS. WINDS WILL REMAIN LGT AND VRB THROUGH TONIGHT...BUT WILL
BEGIN TO APPROACH 10 KTS OUT OF THE S TO W ACROSS MN AS THE SECOND
SHORT WAVE DRIVES A WEAK COLD FRONT ACROSS THE AREA.
KMSP...WITH MVFR SN BEING REPORTED AS FAR NORTH AS AXN...DECIDED
TO INTRODUCE SOME TEMPO MVFR -SN. EXPECT THE NORTH EDGE OF THE SNOW
TO RUN DOWN I-94 INTO THE CITIES...BUT IT COULD REMAIN SOUTH OF
THE AREA. WITH THE SECOND WAVE DROPPING ACROSS MN TONIGHT...MAY
HAVE A PROLONGED PERIOD THROUGH ABOUT 15Z WHERE MSP COULD SEE
BOUTS OF SNOW AND MVFR CIGS...BUT EXPECT PREDOMINATE CONDITIONS TO
REMAIN VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JPR
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
355 PM EST FRI DEC 16 2011
.SYNOPSIS...
A COLD FRONT IS MOVING SOUTHEAST ACROSS FORECAST AREA. THIS
FRONT WILL STALL ACROSS NORTH CAROLINA TODAY. A WAVE OF LOW
PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONT THIS
AFTERNOON...SPREADING RAIN NORTHWARD ACROSS THE AREA...AND THEN
MOVE OFF THE MID ATLANTIC COAST BY SATURDAY MORNING. HIGH PRESSURE
WILL BUILD BACK ACROSS THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 400 PM EST FRIDAY
RAIN CONTINUES TO MOVE ACROSS THE CWA THIS AFTERNOON. A SURGE OF DRY
AIR IN THE LOW LEVELS FROM THE NORTHEAST HAS ALLOWED SOME SLEET TO
MIX IN WITH THE RAIN NORTH OF ROUTE 460. THE BRIEF BREAK IN THE
PRECIP OVER WESTERN AREAS WILL FILL IN THIS AFTERNOON AND
EVENING AS THE SECOND AREA OF RAIN OVER EASTERN KENTUCKY AND
TENNESSEE MOVES ACROSS. THIS RAIN IS BEING CAUSED BY STRONG
ISENTROPIC LIFT IN THE LOWER AND MID LEVELS OUT AHEAD OF AN UPPER
LEVEL WAVE MOVING ACROSS EASTER MISSOURI AND ILLINOIS...AND OVER TOP
THE SURFACE COLD FRONT THAT HAS STALLED JUST TO OUR SOUTH. THIS AREA
OF ISENTROPIC LIFT PUSHES OFF TO OUR EAST PRETTY QUICKLY BETWEEN 7
AND 10 PM. HRRR HAS BEEN HANDLING THIS STORM FAIRLY WELL TODAY...AND
THE LATEST RUN SHOWS THAT THE UPPER LEVEL WAVE WILL CATCH UP WITH
OUR RAIN SHIELD AROUND 9 OR 10PM. ENOUGH MOISTURE WILL STILL BE
PRESENT IN THE COLUMN THAT THIS ADDITIONAL LIFT WILL LIKELY BRIEFLY
ENHANCE THE PRECIP SOMETIME BETWEEN 8PM AND MIDNIGHT. ONCE THIS WAVE
PUSHES ACROSS...RAIN WILL QUICKLY SHUT OFF...WITH IT CLEARING EASTERN
AREAS BY AROUND MIDNIGHT. UPSLOPE CLOUDS WILL PERSIST ACROSS THE
MOUNTAINS THROUGH THE NIGHT...WITH POSSIBLY A FEW SNOW SHOWERS...BUT
NOT EXPECTING MUCH AS MOISTURE BECOMES VERY SHALLOW. MAY SEE SOME
AREAS OF FREEZING DRIZZLE AND FREEZING FOG ACROSS THE HIGHER
ELEVATIONS...ESPECIALLY ACROSS WESTERN GREENBRIER AND NORTHWEST
NORTH CAROLINA. TEMPERATURES WILL DROP BELOW FREEZING IN NORTHWEST
NORTH CAROLINA TOWARDS MORNING...AND THEY WILL LIKELY BE STUCK IN A
THICK LOW CLOUD...WITH SOME ICING AND FREEZING DRIZZLE POSSIBLE.
ANY SNOW FROM THE MAIN BATCH OF PRECIP THIS AFTERNOON AND EVENING
WILL BE CONFINED TO THE HIGHER ELEVATIONS OF SOUTHEAST WEST VIRGINIA
AND THE ALLEGHENY HIGHLANDS. IT IS HERE WHERE TEMPERATURES ALOFT
COOL ENOUGH FOR SNOW THIS EVENING. LOWER ELEVATIONS IN THIS REGION
WILL BE ABOVE FREEZING...AND THUS EXPECT A NON ACCUMULATING RAIN
SNOW MIX. THE HIGHER ELEVATIONS OF
GREENBRIER...SUMMERS...MONROE...AND BATH COUNTIES MAY PICK UP AROUND
AN INCH. WHEN THE PRECIP EXITS...OTHER LOCATIONS WEST OF THE NEW
RIVER VALLEY MAY SEE A BRIEF CHANGE TO SNOW...BUT NOT MORE THAN A
COATING EXPECTED...AS PRECIP WILL BE ENDING AS THE COLD AIR ARRIVES.
WENT CLOSER TO THE WARMER MAV GUIDANCE FOR LOWS TONIGHT AS WINDS
WILL LIKELY STAY UP...WHICH COMBINED WITH SOME CLOUDS...SHOULD
PREVENT MOST AREAS FROM DECOUPLING. SATURDAY WILL BE A MOSTLY SUNNY
DAY...WITH LOW CLOUDS IN THE MOUNTAINS SLOWLY DISSIPATING BY
AFTERNOON. CAA AND 850MB TEMPS IN THE -3C TO -7C RANGE WILL MAKE FOR
A COLD DAY. WENT SLIGHTLY BELOW MOS GIVEN EXPECTED CAA
REGIME...WHICH GIVES TEMPERATURES AROUND 40 IN THE WEST...AND IN THE
MID TO UPPER 40S EAST...GENERALLY A FEW DEGREES BELOW AVERAGE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM EST FRIDAY...
TROUGH SHARPENS A BIT OVER THE MIDDLE ATLANTIC AS THE LAST SHRTWV
ENTERS IT BEFORE A MORE ZONAL UPPER FLOW PATTERN RETURNS EARLY NEXT
WEEK. ALTHOUGH MOISTURE IS SHALLOW...ENOUGH LIFT WITH THIS
DISTURBANCE...SUFFICIENTLY COLD AIR AND UPSLOPE FLOW WILL PRODUCE
SOME SNOW SHOWERS ALONG WESTERN GREENBRIER WITH POSSIBLY SOME
FLURRIES SURVIVING INTO THE SOUTHERN SHENANDOAH AND NEW RIVER VALLEY
INTO SUNDAY MORNING. NOTHING MORE THAN A QUICK COATING OF SNOW IS
EXPECTED THROUGH WESTERN GREENBRIER DURING THIS PERIOD. BASED ON H85
TEMPS GUIDANCE LOOKS A LITTLE WARM FOR SUNDAY. HIGH PRESSURE
ARRIVING BEHIND THIS WAVE SHOULD PRODUCE A VERY COLD MONDAY MORNING
WITH SOME UPPER TEENS POSSIBLY IN THE SHELTERED VALLEYS. SW RETURN
FLOW QUICKLY ARRIVES ON MONDAY AS HIGH PRESSURE MOVES SW TO THE
CAROLINA COAST...ALLOWING AFTERNOON READINGS TO TOUCH 50F AGAIN IF
HIGH CLOUDS HOLD OFF UNTIL MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 PM EST FRIDAY...
THE UPPER RIDGE THAT WAS OVER THE REGION ON MONDAY WILL BE SHORT
LIVED PRIOR TO THE REGION TRANSITIONING INTO A PROGRESSIVE PATTERN.
WE ARE EXPECTING THE CENTER OF THE UPPER RIDGE TO SHIFT SOUTHEAST TO
OVER THE CARIBBEAN BY THE MIDDLE OF NEXT WEEK. THIS WILL OPEN THE
DOOR FOR A PATTERN OF GENERAL TROUGHINESS ACROSS THE CENTER OF THE
COUNTRY WITH DISTINCT SYSTEMS ROUNDING THE BASE OF THE
TROUGH...COLLECTING SOME GULF OF MEXICO MOISTURE...AND THEN MOVING
ACROSS OUR REGION. MODEL GUIDANCE HAS BEEN SHOWING TO UNIQUE
ATTRIBUTES. THE GFS HAS BEEN MORE PROGRESSIVE WITH THE SYSTEMS
COMPARED RELATIVELY WITH THE ECWMF. BOTH SOLUTIONS HAVE BEEN
TRENDING SLOWER ON ARRIVAL TIMES AS COMPARED TO EARLIER MODEL RUNS.
THIS I BELIEVE SUPPORTS FAVORING THE SLOWER ECMWF SOLUTIONS...WITH
ANTICIPATION THAT IT TOO WILL CONTINUE TO TREND SLOWER TO SOME
DEGREE WITH EACH NEW MODEL RUN. THIS LINE OF THINKING IS
COMPARABLE...NOT NOT IDENTICAL TO THE GRIDDED GUIDANCE PUT FORTH BY
HPC. WILL USED A MODIFIED APPROACH TO THE HPC GUIDANCE
TODAY...KEEPING A SLOWER TREND OF SYSTEMS IN MIND.
GRADUALLY DURING THE DAY TUESDAY...EXPECT LIGHT RAIN TO GRADUALLY
SPREAD ACROSS THE REGION FROM WEST TO EAST IN ASSOCIATION WITH
DEVELOPING WARM FRONT JUST TO OUR NORTH. THE COVERAGE IS EXPECTED TO
INCREASE TUESDAY NIGHT AS ISENTROPIC LIFT INCREASES EVEN MORE. ON
WEDNESDAY...THE CENTER OF LOW PRESSURE WILL PASS NEAR WV/PA WITH AN
ASSOCIATED COLD FRONT MOVING ACROSS OUR REGION. ANTICIPATE THE
PRECIPITATION TO BECOME MORE SHOWERY. CONVECTIVE PARAMETERS ARE
SUGGESTING SOME VERY WEAK CAPE AND LI VALUES AROUND ZERO IN THE
AFTERNOON IN THE EASTERN PART OF THE ARE. NOT IMPRESSIVE NUMBERS FOR
THE SUMMERTIME...BUT FOR MID DECEMBER...I BELIEVE IT WARRANTS A
MENTION OF ISOLATED THUNDER. THIS SYSTEM WILL EXIT THE REGION
QUICKLY WEDNESDAY NIGHT WITH A BRIEF PERIOD OF UPSLOPE RA/SN SHOWERS
ACROSS SE WV.
DRY WEATHER BRIEFLY RETURNS ON THURSDAY. HOWEVER...FOR FRIDAY EXPECT
A SITUATION COMPARABLE TO WHAT IS EXPECTED FOR TUESDAY. INSENTROPIC
LIFT WILL BEGIN TO ORGANIZE IN ADVANCE OF ANOTHER QUICK MOVING
SYSTEM MOVING THROUGH THE WESTERN GULF COAST STATES. WHILE WE ONLY
MENTION RAIN OR SNOW FOR PRECIPITATION TYPES THIS FAR OUT IN THE
FORECAST BECAUSE OF THE UNCERTAINTY FACTOR...LATEST LOW LEVEL
TEMPERATURE AND MOISTURE PROFILES SUGGEST THAT FREEZING RAIN OR
SLEET COULD OCCUR ALONG AND NEAR THE I-64 CORRIDOR OF WV AND
NEIGHBORING SW VA WEST OF I-81 LATE THURSDAY NIGHT INTO FRIDAY
MORNING...BEFORE TRANSITIONING TO RAIN AS LOW LEVEL AND SURFACE
TEMPERATURES RISE THROUGHOUT THE DAY.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1235 PM EST FRIDAY...
A SHORT WAVE MOVING QUICKLY ACROSS THE TENNESSEE VALLEY WILL BRING
AN AREA OF PRECIPITATION...AND ASSOCIATED MVFR CEILINGS...THROUGH
THE FORECAST AREA BEFORE 06Z TONIGHT. BASED ON RADAR TRENDS AT
17Z...THE LEADING EDGE OF THE RAINFALL WILL REACH DAN AND LYH
AROUND THE START OF THE 18Z TAF PERIOD.
COLDER AIR SINKING SOUTH THROUGH THE MID ATLANTIC REGION WILL COLL
THE AIR MASS THIS AFTERNOON AND TONIGHT. BUFKIT SOUNDINGS SHOWED
TEMPERATURES COOL ENOUGH FOR SNOW AT LWB...BLF AND POSSIBLY BCB BY
AROUND 00Z TONIGHT. ANY SNOW FALL AMOUNTS WILL REMAIN LIGHT WITH
THE PRECIPITATION ENDING AT THESE STATIONS BY 03Z.
LOWER CONFIDENCE WITH THREAT OF FOG OVERNIGHT ONCE THE
PRECIPITATION ENDS. IF CLOUDS CLEAR OUT QUICKLY THE PROBABILITY OF
MVFR TO IFR FOG WILL BE HIGHER.
A WEAK SHORT WAVE IN THE NORTHERN STREAM WILL BRIEFLY BRING MVFR
CEILINGS BACK INTO SOUTHEAST WEST VIRGINIA...INCLUDING BLF AND LWB
SATURDAY AFTERNOON AND EVENING...POSSIBLY WITH SOME LIGHT SNOW
SHOWERS. OTHERWISE...HIGH PRESSURE WILL THEN FOLLOW THIS SYSTEM
LATER SATURDAY INTO SUNDAY RESULTING IN A RETURN TO VFR ACROSS
THE REGION FOR THE END OF THE WEEKEND.
ANOTHER COLD FRONT AND LOW PRESSURE SYSTEM WILL APPROACH THE
REGION FROM THE WEST TUESDAY...AND MAY BRING SUB-VFR CONDITIONS BY
TUE NIGHT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JJ/MC
NEAR TERM...MC
SHORT TERM...KM
LONG TERM...DS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
327 PM CST FRI DEC 16 2011
.SHORT TERM...
326 PM CST FRI DEC 16 2011
HAVE INCREASED SNOW CHANCES TONIGHT ACROSS THE SOUTH INTO LIKELY
CATEGORY. THIS WAS BASED ON 18Z NAM/LATEST RUC TRENDS WHICH NOW
SHOW COLUMN SATURATION SHOULD BE MUCH OF A PROBLEM GIVEN FAIRLY
STRONG PUSH OF ISENTROPIC LIFT AND MODERATE BAND OF 850-700MB
FRONTOGENESIS CENTERED AROUND 06Z. CURRENT THINKING IS THAT AROUND
A HALF INCH OF SNOW WILL BE POSSIBLE WITH THE MAIN AXIS EXTENDING
FROM NEAR ROCHESTER MN TO PLATTEVILLE WI.
REST OF PREVIOUS SHORT TERM DISCUSSION:
NORTHWEST FLOW CONTINUES TO AFFECT THE AREA ON SATURDAY AS YET
ANOTHER SHORTWAVE TROUGH ROTATES OUT OF CANADA TOWARD THE AREA. THIS
TIME IT APPEARS THE BEST FORCING WILL REMAIN NORTHEAST OF I-94...SO
KEPT CHANCE CONFINED ACROSS THAT AREA. THIS BEING SAID...IT APPEARS
LIKE ANOTHER VERY LIGHT SNOW EVENT WITH NOT MUCH MORE THAN A COUPLE
TENTHS OF AN INCH EXPECTED.
WITH MAIN UPPER LEVEL TROUGHINESS PUSHING EAST OF THE REGION ON
SUNDAY...HEIGHTS BUILD NICELY ACROSS THE PLAINS/UPPER MISSISSIPPI
RIVER REGION. THE NAM BRINGS 925MB AIR OF 4-8C INTO THE AREA WITH
AMPLE SUNSHINE. WITH BARE GROUND...THIS HEATING SHOULD WARM HIGHS
INTO THE 35-40 DEGREE RANGE NORTHEAST OF I-94...AND INTO THE 40-45
DEGREE RANGE ACROSS THE SOUTHWEST.
A COLD FRONT IS THEN SLATED TO MOVE ACROSS THE AREA SUNDAY
NIGHT/MONDAY. NAM DOES INDICATE AN INCREASE IN LOWER LEVEL 0.5-1KM
RH/STRATUS ACROSS THE AREA AS THE FRONT APPROACHES PASSES. MAY HAVE
TO KEEP AN EYE ON THIS FOR PERHAPS SOME DRIZZLE POTENTIAL...BUT WILL
KEEP DRY FOR NOW.
CLEARING THEN EXPECTED MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM
THE NORTHERN PLAINS.
.LONG TERM...TUESDAY THROUGH FRIDAY
205 PM CST FRI DEC 16 2011
16.12Z GFS/ECMWF MAINTAIN A RATHER QUIET WEATHER REGIME ACROSS THE
REGION THROUGH THE PERIOD WITH SPLIT NORTHERN/SOUTHERN STREAM FLOW.
THIS KEEPS CYCLONE TRACKS ACROSS CANADA AND ACROSS THE SOUTHERN
PLAINS/SOUTHEAST WITH OUR AREA DRY THROUGH THURSDAY. MAY HAVE TO
WATCH FOR LAST-DITCH CHANCE FOR A WHITE CHRISTMAS CHANCE OF LIGHT
SNOW ON FRIDAY AS A MID-LEVEL TROUGH PASSES ACROSS THE AREA. THE
ECMWF REMAINS DRY WITH THIS FEATURE WHILE THE GFS SHOWS SOME
FRONTOGENESIS/BAND OF LIGHT SNOW POTENTIAL. WENT WITH THE MODEL
CONSENSUS/SLIGHT CHANCE POP FOR NOW.
&&
.AVIATION...THROUGH 18Z SATURDAY
1135 AM CST FRI DEC 16 2011
UPSTREAM SHORT WAVE TROUGH OVER THE DAKOTAS IS SET TO MOVE ACROSS
THE AREA TONIGHT. BOTH THE 16.12Z NAM AND GFS SUGGEST THIS WAVE
WILL BE STRONG ENOUGH TO PRODUCE SATURATION RESULTING IN SOME
LIGHT SNOW FOR BOTH TAF SITES. UPSTREAM OBSERVATIONS INDICATE THE
SNOW IS ENOUGH TO REDUCE THE VISIBILITY TO MVFR WITH SOME IFR
POSSIBLE AS WELL. WILL USE THESE OBSERVATIONS AS A STARTING POINT
AND TAKE THE VISIBILITY DOWN TO IFR FOR KRST AS THE QUICK MOVING
SNOW BAND COMES IN THIS EVENING. FOR NOW...WILL STAY WITH MVFR AT
KLSE BUT WILL GO SLIGHTLY LOWER THAN THE PREVIOUS FORECAST. THE
SNOW SHOULD END BEFORE SUNRISE FOR BOTH LOCATIONS WITH VFR
CONDITIONS QUICKLY RETURNING. ANOTHER SHORT WAVE WILL DROP OUT OF
CANADA SATURDAY...BUT THE FORCING AND MOISTURE FROM THIS WAVE
SHOULD STAY ACROSS THE GREAT LAKES WITH LITTLE IMPACT EXPECTED AT
EITHER TAF SITE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
205 PM CST FRI DEC 16 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM.... DAS
AVIATION..... 04