Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/21/14

AREA FORECAST DISCUSSION

NWS RENO NV

 250 PM PST FRI DEC 19 2014

.SYNOPSIS...
CHANCES FOR RAIN AND SNOW WILL GRADUALLY DIMINISH FROM SOUTH TO
NORTH THROUGH SATURDAY. ANY AMOUNTS WILL REMAIN LIGHT. HIGH
PRESSURE WILL BUILD IN FOR EARLY NEXT WEEK WITH MILD TEMPERATURES.
A STRONG COLD FRONT IS POSSIBLE LATE WEDNESDAY INTO THURSDAY WITH
SOME GUSTY WINDS, RAIN AND SNOW.

&&

.SHORT TERM...
MAIN BAND OF RAIN/SNOW IS NOW ALONG A SOUTH LAKE TO BATTLE MTN.
LINE AND IS PUSHING SOUTH AND EAST. THIS BAND WILL WEAKEN OVER THE
NEXT FEW HOURS WITH LIGHT AMOUNTS UP TO A TENTH OF AN INCH.
OTHERWISE ONLY EXPECT ISOLD SHOWERS WITH ONE EXCEPTION. BOTH THE
NAM AND HRRR SHOW ANOTHER BAND OF PRECIP DEVELOPING OVER CENTRAL
CA AND MOVING NORTHEAST INTO THE TAHOE BASIN THIS EVENING. A WEAK
WAVE IS PRESENT IN SATELLITE IMAGERY NEAR 127W AND THIS LOOKS LIKE
IT WOULD BE THE TRIGGER. KEPT SCT SNOW SHOWERS GOING IN THE SIERRA
FROM CARSON TO YUBA PASSES FOR THIS WAVE ALTHOUGH IT MAY BE MORE
WIDESPREAD THAN THIS. ANOTHER COUPLE INCHES OF SNOW REMAIN
POSSIBLE IN THIS BAND IF IT DEVELOPS.

A MILD NIGHT TONIGHT WITH CONTINUED CLOUD COVER AS ANOTHER STORM
MOVES INTO OREGON FOR SATURDAY. WE WILL CONTINUE TO SEE ABUNDANT
CLOUD COVER, BUT THE FORCING WITH THIS NEXT STORM WILL REMAIN WILL
NORTH WITH THE UPPER JET INTO THE COLUMBIA RIVER. THE EXCEPTION
WILL BE NORTH OF A SUSANVILLE TO GERLACH LINE WHERE SOME GOOD
ISENTROPIC LIFT IS SHOWING UP SATURDAY MORNING. INCREASED THE
THREAT OF RAIN/SNOW THERE WHILE KEEPING IT LOW CHANCE TO SLIGHT
CHANCE FURTHER SOUTH. IT APPEARS THERE WILL BE ABOUT A TENTH TO
QUARTER INCH OF PRECIP WITH IT.

THE GREATEST UNCERTAINTY THERE WILL BE THE SNOW LEVEL AND PRECIP
TYPE ON VALLEY FLOORS. NORMALLY IN A GOOD WARM AIR ADVECTION EVENT
LIKE THIS IT WOULD START AS SNOW WITH SOME ISOTHERMAL TEMP
PROFILES. HOWEVER, SURFACE TEMPS AND DEWPOINTS ARE 35-40 AND SEE
NO SIGNIFICANT DRYING OR COOLING TONIGHT AS MOISTURE AND CLOUDS
CONTINUE TO ARRIVE. RIGHT NOW, PUT SNOW LEVELS 4500-5000 FEET WITH A
RAIN/SNOW MIX IN THE SURPRISE VALLEY. IF IT IS ALL SNOW 1-2 INCHES
OF SNOW IS POSSIBLE BUT MY GUESS IS IT WILL BE IN THE FORM OF
RAIN.

BEHIND THE WARM FRONT, MID/HIGH CLOUDS WILL DIMINISH SATURDAY
NIGHT INTO SUNDAY. SOME SCATTERED LOW CLOUDS WILL CONTINUE AS
ABUNDANT LOW LEVEL MOISTURE GETS TRAPPED UNDER A SUBSIDENCE
INVERSION WITH THE STRONG RIDGE BUILDING IN. TEMPERATURES WILL
REMAIN MILD AND ABOVE NORMAL INTO EARLY NEXT WEEK WITH 50S DURING
THE DAY AND 20S AND 30S OVERNIGHT, COLDEST IN SIERRA VALLEYS.
WALLMANN

.LONG TERM...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE OVER THE WEST WILL GIVE WAY AROUND MID WEEK AS A
FAST-MOVING LOW PRESSURE SYSTEM MOVES INTO THE WEST COAST ON
CHRISTMAS EVE. THE GFS KEEPS THE SYSTEM FLAT AS IT MOVES THROUGH
THE REGION WHILE THE ECMWF/UKMET ARE BRINGING A STRONGER, DIGGING
SYSTEM INTO THE REGION. THE NWS WEATHER PREDICTION CENTER CONCURS
WITH A DIGGING SYSTEM AND THIS SOUNDS APPROPRIATE AS STRONG
SHORTWAVE ENERGY MOVING OFF OF JAPAN SATURDAY ARRIVES AT THE WEST
COAST ON WEDNESDAY (WHICH WOULD ENHANCE THE SYSTEM).

AS FAR AS THE DETAILS, THE DEVIL REMAINS AS THE 12Z ECMWF AND GEM
ARE NOW IMPLYING SOME SPLITTING AS THE SYSTEM MOVES INTO THE SIERRA
AND WESTERN NEVADA. I WOULD STILL EXPECT PRECIPITATION (AT LEAST IN
THE SIERRA AND IN THE BASIN NORTH OF HIGHWAY 50) WHETHER THE SYSTEM
BEGINS TO SPLIT OR NOT, ESPECIALLY AS THE GFS/EC SHOW A MODERATE
MOISTURE FEED (PWATS APPROACHING ONE INCH) BEING PULLED OFF OF A
SUBTROPICAL LOW NEAR HAWAII. HOWEVER, THE SPLIT WOULD LOWER
PRECIPITATION TOTALS AS THE SYSTEM`S COLD FRONT WEAKENS/FRACTURES.
ALSO, IT WOULD DELAY THE PUNCH OF COLD AIR ENOUGH THAT PRECIPITATION
WOULD START AS RAIN INITIALLY BELOW 5000-5500 FEET RATHER THAN BE A
MAINLY SNOW EVENT PER THE UNSPLIT/CONSOLIDATED SOLUTIONS.

AS FAR AS IMPACTS FOR EASTERN CALIFORNIA AND WESTERN NEVADA FOR THE
CHRISTMAS HOLIDAY, WIND GUSTS TO 35-45 MPH IN THE LOWER ELEVATIONS
ARE POSSIBLE WEDNESDAY WHICH WOULD CLEAR OUT ANY HAZE/POLLUTANTS IN
THE VALLEYS AND WARM HIGHS INTO THE 50S TO NEAR 60. PRECIPITATION
WISE, SNOW OR RAIN AND SNOW MAY START TO MOVE INTO AREAS NORTH OF
INTERSTATE 80 BY LATE WEDNESDAY AFTERNOON, THEN ACROSS THE
RENO-TAHOE AREA DURING CHRISTMAS EVE. THOSE TRAVELING CHRISTMAS EVE
AND CHRISTMAS MORNING SHOULD KEEP AN EYE ON THE FORECAST WITH
POTENTIAL IMPACTS DUE TO SNOW IN THE SIERRA AND ON THE LOWER VALLEY
FLOORS.

AFTER THE SYSTEM PASSES, A COLD NORTH SURFACE FLOW IS EXPECTED TO
KEEP AFTERNOON HIGHS FOR VALLEYS ON THURSDAY/CHRISTMAS DAY AND
FRIDAY IN THE 30S. THE CAVEAT IS THAT IF AT LEAST A FEW INCHES OF
SNOW FALLS ON CHRISTMAS EVE HIGHS ARE LIKELY TO REMAIN IN THE 20S
ALL DAY FOR LATE NEXT WEEK. FOR LOWS, SNOWFALL WOULD PUSH LOWS FROM
THE SINGLE DIGITS AND TEENS TO BELOW ZERO FOR MANY VALLEY LOCATIONS.
SNYDER

&&

.AVIATION...
A FRONT MOVING THROUGH THE AREA IS PRODUCING -SN/SN AND IFR
CONDITIONS IN THE SIERRA WITH ISOLD/SCATTERED SHOWERS AND HIGHER
TERRAIN OBSCURATION IN WESTERN NEVADA, MAINLY NORTH OF HIGHWAY 50.
THE FRONT IS ALSO KICKING UP WINDS GUSTS TO 20-25 KTS IN WESTERN
NEVADA NEAR/SOUTH OF I-80 AND DOWN INTO EASTERN MONO COUNTY.
FINALLY, TURBULENCE AND LIGHT RIMING ARE ALSO A GOOD BET OVER THE
SIERRA AND INTO WESTERN NEVADA WITH A RECENT PIREP INDICATING THIS
BETWEEN 090-190 MSL NEAR RENO.

FOR THIS EVENING, ANOTHER UPPER DISTURBANCE APPROACHING THE NORTHERN
CALIFORNIA COAST IS EXPECTED TO ENHANCE NORTHERN SIERRA SNOWFALL.
GIVEN THAT THE NEXT ROUND OF SIERRA SNOW WILL ARRIVE AFTER SUNSET
THERE COULD BE AN INCH OR TWO OF ACCUMULATION ON UNTREATED TARMACS
AND RUNWAYS AT KTRK AND KTVL. PLENTY OF MOISTURE AND A FEW LEFTOVER
-SHSN SHOULD ALLOW AREAS OF LOW CIGS AND TERRAIN OBSCURATION TO
PERSIST OVERNIGHT FOR THE SIERRA AND PORTIONS OF NORTHEAST
CALIFORNIA.

SATURDAY, ONE MORE ROUND OF LIGHT LOWER VALLEY RAIN AND MOUNTAIN
SNOW WILL AFFECT NORTHEAST CALIFORNIA AND NORTHERN NEVADA. THIS WILL
MEAN HIGHER TERRAIN OBSCURATION AND PERIODS OF MVFR CIGS FOR
NORTHERN SIERRA (KTVL/KTRK) TERMINALS, AS WELL AS THE POSSIBILITY
FOR BRIEF MVFR CIGS OUT INTO WESTERN NEVADA NORTH OF INTERSTATE 80.
SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)






AREA FORECAST DISCUSSION...UPDATED

NWS RENO NV

 847 AM PST FRI DEC 19 2014

.UPDATE...
MAIN PRECIP BAND IS HOLDING TOGETHER FAIRLY WELL AS IT MOVES
TOWARD THE I-80 CORRIDOR THIS MORNING. IT HAS ALSO BEEN SPILLING
OVER FAIRLY WELL INTO THE LEESIDE VALLEYS WHICH IS MORE THAN
WE EXPECTED YESTERDAY AND LAST NIGHT. GIVEN THE NATURE OF THE
BAND, THE SPILLOVER AND THE LATEST HRRR WHICH KEEPS THE BAND
INTACT THROUGH I-80 WILL UPDATE THE FORECAST. THE MAIN CHANGE IS
TO INCREASE THE CHANCES OF RAIN/SNOW ALONG THE I-80 CORRIDOR
THROUGH EARLY AFTERNOON. THE RAIN/SNOW WILL ONLY LAST 2-4 HOURS,
LONGEST IN THE SIERRA, BUT IT WILL BE NOTICEABLE. PRECIP AMOUNTS
OF AROUND 1/4 INCH FOR THE TAHOE BASIN WITH UP TO A TENTH IN
WESTERN NEVADA.

SNOW LEVELS ARE RUNNING SLIGHTLY HIGHER THAN FORECAST WITH THE
CHICO PROFILER AT 7000 FEET SIGNIFICANTLY HIGHER. SLIDE TEMPS ARE
RUNNING 22-23 DEGREES AND WHILE THE TAHOE BASIN IS ABOVE FREEZING,
DEW POINTS ARE LOW. THIS SHOULD RESULT IN WET BULBING THAT WILL
BRING SNOW TO LAKE LEVEL AS WELL. WILL RAINS SNOW LEVELS SLIGHTLY
TO 5500-6000 FEET WITH LIGHT AMOUNTS OF 1-3 INCHES FOR THE BASIN
AND PERHAPS UP TO 6 INCHES NEAR THE CREST ABOVE 7000 FEET. AFTER
THE BAND MOVES THROUGH, EXPECT ONLY ISOLD-SCT SHOWERS INTO THE
EVENING. WALLMANN

&&

.PREVIOUS DISCUSSION... /ISSUED 221 AM PST FRI DEC 19 2014/

SYNOPSIS...
CHANCES FOR RAIN AND SNOW WILL PERSIST NORTH OF HIGHWAY 50 THROUGH
SATURDAY AS COUPLE OF WEAK SYSTEMS BRUSH NORTHEASTERN CALIFORNIA AND
WESTERN NEVADA. HIGH PRESSURE WILL THEN BUILD SUNDAY THROUGH THE
FIRST PART OF NEXT WEEK. A COOLING TREND AND SNOW ARE POSSIBLE FOR
CHRISTMAS EVE.

SHORT TERM...
MINOR ADJUSTMENTS MADE TO THE ONGOING FORECAST THIS MORNING AS A
WEAK SYSTEM BRUSHES ACROSS NORTHEASTERN CALIFORNIA AND NORTHERN
NEVADA.

A PRECIPITATION BAND AHEAD OF THE MAIN COLD FRONT MOVED THROUGH
LASSEN AND PLUMAS COUNTIES EARLY THIS MORNING BRINGING SNOW
SHOWERS TO THOSE AREAS. THE WEB CAM AT BOGARD REST AREA (AROUND 5600
FEET) SHOWED SNOW ACCUMULATING QUICKLY BETWEEN MIDNIGHT AND 1AM
UNDER THE PRECIPITATION BAND. TRAVELERS SHOULD CHECK ROAD
CONDITIONS BEFORE HEADING OUT THIS MORNING AS ROADS MAY BE SLICK OR
SNOW COVERED. AS THE COLD FRONT APPROACHES THE REGION, SNOW
LEVELS WILL REMAIN NEAR 6000-6500 FEET AROUND INTERSTATE 80 AND
4500-5000 FEET NEAR THE OREGON BORDER. LIGHT SNOW AMOUNTS OF UP TO
A COUPLE INCHES ARE POSSIBLE ABOVE 5500 FEET THROUGH THE MORNING
WITH HIGHER AMOUNTS TO 6 INCHES NEAR THE SIERRA CREST.

THE SYSTEM PUSHES THROUGH THE REGION TONIGHT WITH MOIST UPSLOPE FLOW
ALLOWING RESIDUAL SHOWERS TO CONTINUE ALONG THE CREST. THE NEXT
ROUND OF PRECIPITATION PUSHES INTO AREAS FROM THE TAHOE BASIN
EXTENDING NORTH INTO NORTHERN LASSEN, WASHOE, AND CHURCHILL COUNTIES
AS A RESULT OF WARM AIR ADVECTION. AGAIN THE BEST CHANCES APPEAR TO
REMAIN RIGHT ALONG THE NEVADA/OREGON BORDER WITH CHANCES DROPPING
OFF SIGNIFICANTLY FURTHER SOUTH. MODEL SOUNDINGS CONTINUE TO SHOW AN
ISOTHERMAL LAYER WHICH MAY ALLOW SNOW LEVELS NEAR THE OREGON BORDER
TO REMAIN NEAR VALLEY FLOORS, BUT SNOW LEVELS WILL BE ON THE RISE
LATE SATURDAY INTO SUNDAY AS THE WARM FRONT PUSHES THROUGH.

AFTER THIS SYSTEM PASSES THROUGH SATURDAY NIGHT, THE RIDGE AMPLIFIES
OFF THE WEST COAST BRINGING A WARMING AND DRYING TREND. SKIES WILL
REMAIN FAIRLY CLOUDY UNDER THE DIRTY RIDGE PATTERN, ESPECIALLY NORTH
OF INTERSTATE 80, WHICH WILL HELP TO MODERATE TEMPERATURES
OVERNIGHT. OTHERWISE RIDGING THROUGH THE WEEKEND MAY ALLOW SURFACE
INVERSIONS TO DEVELOP WHICH WILL RESULT IN FASTER WARMING FOR RIDGE
TOP TEMPERATURES THAN THE VALLEYS. WEISHAHN

LONG TERM...MONDAY THROUGH CHRISTMAS...

HIGH PRESSURE OVER THE WEST WILL GIVE WAY AROUND MID WEEK AS LOW
PRESSURE MOVES INTO THE WEST COAST. MODELS SOLUTIONS SHOWED A
MODERATE AMOUNT OF AGREEMENT SO FORECAST CONFIDENCE IS MEDIUM IN A
SYSTEM MOVING INTO THE REGION ON CHRISTMAS EVE. MODELS CONTINUE TO
SHOW A FRONT REACHING NORTHERN CALIFORNIA AND NORTHWEST NEVADA ON
WEDNESDAY. THE FRONT SHOULD INCREASE GUSTS TO NEAR 45 MPH IN THE
LOWER ELEVATIONS, WHICH WILL HELP CLEAR OUT ANY HAZE/POLLUTANTS IN
THE VALLEYS AND MAY WARM HIGHS INTO THE 50S TO NEAR 60.
PRECIPITATION MAY START TO MOVE INTO AREAS NORTH OF INTERSTATE 80 BY
LATE WEDNESDAY AFTERNOON, THEN ACROSS THE RENO-TAHOE AREA DURING
CHRISTMAS EVE. THOSE TRAVELING CHRISTMAS EVE AND CHRISTMAS MORNING
SHOULD KEEP AN EYE ON THE FORECAST FOR POTENTIAL IMPACTS DUE TO
SNOW OVER THE SIERRA PASSES AND ON THE NEVADA VALLEY FLOORS. AFTER
THE SYSTEM PASSES, A COLD NORTH SURFACE FLOW COULD KEEP AFTERNOON
HIGHS ON CHRISTMAS DAY IN THE 20S AND 30S. BRONG

AVIATION...

COLD FRONT MOVING THROUGH THE AREA IS PRODUCING SNOW AND IFR
CONDITIONS IN THE NORTHERN SIERRA WITH SCATTERED SHOWERS AND MVFR
CONDITIONS EAST OF THE SIERRA. THE FRONT IS FORECAST TO WEAKEN AS IT
MOVES SOUTH THIS MORNING, THOUGH THERE IS ENOUGH MOISTURE AND
INSTABILITY TO PRODUCE SNOW AROUND THE TAHOE BASIN WITH ISOLATED TO
SCATTERED SHOWERS ACROSS WESTERN NEVADA. THERE COULD BE AN INCH OR
TWO OF ACCUMULATION ON TARMACS/RUNWAYS AT KTRK AND KTVL TODAY. THE
FRONT WILL ALSO KICK UP GUSTS TO NEAR 30KTS THIS MORNING ALONG AND
SOUTH OF KTRK-KRNO-KLOL.

A FEW LIGHT SHOWERS SHOULD BREAK INTO THE VICINITY OF KRNO AND KCXP
BY 17Z, BUT TEMPERATURES MAY WARM ENOUGH TO GET THE SNOW LEVEL OFF
THE NEVADA VALLEY FLOORS. BRONG

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)






AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 1012 PM EST SAT DEC 20 2014

.SYNOPSIS...
UNSETTLED WEATHER IS EXPECTED OVERNIGHT THROUGH TUESDAY AS
SEVERAL DISTURBANCES MOVE OVER THE REGION. A STRONG COLD FRONT
WILL APPROACH LATE TUESDAY NIGHT...THEN SHIFT THROUGH THE AREA ON
WEDNESDAY. DRY HIGH PRESSURE WILL THEN SETTLE OVER THE SOUTHEAST
THROUGH LATE WEEK...WITH A COLD FRONT EXPECTED NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LATE SATURDAY EVENING...SATELLITE IMAGERY AND AREA RADAR TRENDS
CONTINUED TO DEPICT A WEAK SHORTWAVE TROUGH ALOFT AND ASSOCIATED
AREAS OF LIGHT RAIN EJECTING ENE TOWARD THE AREA. INITIALLY...
POPS GRADUATED FROM HIGH CHANCE ALONG/SOUTH OF INTERSTATE 16 TO
BELOW 15 PERCENT ACROSS FAR NORTHERN COUNTIES WILL SUFFICE AS
MID/UPPER LEVEL DRY AIR HAS TEMPORARILY OVERSPREAD THE REGION AS
SHOWN BY THE 00Z KCHS SOUNDING AND WATER VAPOR IMAGERY. ALSO...
RECENT SURFACE OBSERVATIONS SUGGEST THAT PRECIPITATION THUS FAR
HAS REMAINED LIGHT. HOWEVER...AS THE NIGHT PROGRESSES...MODEL
CONSENSUS INCLUDING RECENT HIGH RESOLUTION SOLUTIONS SUGGEST THAT
PRECIPITATION COVERAGE WILL INCREASE. ACCORDINGLY...RAMPED UP POPS
OVERNIGHT...EVENTUALLY TAPERED FROM LIKELY/HIGH CHANCE ACROSS
SOUTHERN AND COASTAL COUNTIES TO CHANCE INLAND. GIVEN THE MOST
RECENT RUC13 AND HRRR GUIDANCE...LIGHT RAIN YET BECOME MORE
WIDESPREAD THAN INDICATED WITHIN THE LATE EVENING UPDATE...AND
HIGHER POPS COULD BE REQUIRED WITHIN SUBSEQUENT FORECASTS.

MEANWHILE...WITHIN THE WEDGE REGIME STRATUS COULD PRODUCE SOME
DRIZZLE AND COULD LOWER TOWARD THE SURFACE TO SUPPORT FOG
OVERNIGHT. NEAR THE COAST...PERSISTENT SURFACE WINDS SHOULD
LIMIT THE POTENTIAL FOR SIGNIFICANT DENSE FOG OVERNIGHT...ALTHOUGH
CEILINGS COULD OCCASIONALLY LOWER TO PRODUCE REDUCED VISIBILITY.
FARTHER INLAND...SLIGHTLY HIGHER ELEVATIONS AND LIGHTER WINDS
COULD ENHANCE THE POTENTIAL FOR LOCALLY DENSE FOG.

OTHERWISE...TEMPERATURES WILL FALL ONLY SLOWLY OVERNIGHT AND BY
DAYBREAK WILL RANGE FROM THE LOWER TO MID 40S NORTH TO THE UPPER
40S/LOWER 50S SOUTH AND ON THE COAST.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...A WEAK SOUTHERN STREAM MID LEVEL PERTURBATION MOVING
THROUGH THE LOWER MS VALLEY FROM TONIGHT WILL CROSS THE AREA DURING
THE MORNING HOURS AND REINFORCES THE PRE-EXISTING STATIONARY FRONT
OVER THE ATLANTIC TO THE EAST/SE OF THE GULF STREAM. IT ALSO KEEPS
THE INLAND COOL HIGH PRESSURE WEDGE ANCHORED IN PLACE AS IT EXTENDS
SOUTH OF THE FORECAST AREA. THE IMPULSE ALOFT ALSO TRIGGERS WEAK
CYCLOGENESIS OFF THE SE COAST SOME 250 NM EAST OF SAVANNAH AS IT
MOVES LITTLE THROUGHOUT THE DAY. ISENTROPIC ASCENT WILL AGAIN BE THE
MAIN FACTOR FOR GENERATING RAINFALL...AS IT INCREASES IN MAGNITUDE
DURING THE AFTERNOON AND EVENING HOURS...AND POPS ACCORDINGLY WILL
BE ON THE INCREASE AS WELL DURING THE SECOND HALF OF THE DAY. WE/LL
START THE PERIOD WITH A LITTLE LIGHT RAIN...DRIZZLE AND/OR FOG
BEFORE POPS CLIMB INTO THE 30-50 PERCENTILE IN THE AFTERNOON.
GREATEST PROBABILITIES WILL BE OVER SE GA AND ESPECIALLY SOUTH OF
I-16 DURING THAT TIME. OVERCAST SKIES AND A CONTINUED FEED OF AIR
FROM THE NORTH/NE WITHIN THE LOW LEVEL WEDGE WILL KEEP TEMPS DOWN
MAINLY INTO THE 50S FOR MAX TEMPS.

SUNDAY NIGHT INTO MONDAY...ANOTHER AND SLIGHTLY STRONGER SHORT WAVE
ARRIVES FROM THE GULF OF MEXICO AND FORCES THE ATLANTIC WAVE TO
DEEPEN A FEW MILLIBARS AS IT LIFTS NE ROUGHLY ALONG THE GULF STREAM
TO A POSITION OFF CAPE HATTERAS BY 00Z TUESDAY. THIS PATTERN
REINFORCES THE WEDGE INLAND...WHICH IN TURN ALLOWS FOR A FURTHER
INCREASE IN ISENTROPIC ASCENT. THAT ALONG WITH FORCING FROM THE
UPPER JET OVER THE SE CORNER OF THE COUNTRY AND CONVERGENCE
ASSOCIATED WITH THE NEARBY ATLANTIC LOW WILL CAUSE COVERAGE OF RAIN
TO EXPAND INTO AT LEAST THE 70-80 PERCENT RANGE SUNDAY
NIGHT...BEFORE COVERAGE DIMINISHES FROM WEST TO EST ON MONDAY AS THE
SURFACE LOW PULLS AWAY. PWATS OF 1.3 TO 1.4 INCHES AND THE FLOW
ALOFT OPENING MORE OUT OF THE GULF OF MEXICO SUPPORTS AT LEAST 1/4
TO 1/2 INCH AMOUNTS OF RAIN. IN ADDITION...STEEPER MID LEVEL LAPSE
RATES AND SHOWALTER INDICES DROPPING TO NEAR ZERO COULD SUPPORT A
LITTLE ELEVATED CONVECTION. LOW STRATUS DECKS WILL ALSO SUPPORT SOME
REDUCTION IN SURFACE VISIBILITIES SUNDAY NIGHT INTO MONDAY MORNING
AND WE HAVE ADDED PATCHY FOG TO THE FORECAST. THERE IS ONLY A SMALL
5-10 DEGREE TEMP SWING FROM DAYTIME HIGHS SUNDAY TO NIGHTTIME LOWS
SUNDAY NIGHT. THEN A FAIRLY LARGE NORTH/NW TO SOUTH/SE TEMP GRADIENT
MONDAY WITH HIGHS NEAR OR SLIGHTLY BELOW NORMAL.

MONDAY NIGHT AND TUESDAY...YET ANOTHER QUICK MOVING SOUTHERN STREAM
SHORT WAVE ARRIVES LATE MONDAY NIGHT AND TUESDAY FROM THE GULF OF
MEXICO. FURTHER UPSTREAM A MORE PRONOUNCED SHORT WAVE STARTS TO DIG
THROUGH THE CENTRAL STATES...WHICH IN TURN AMPLIFIES THE LARGE SCALE
PATTERN ACROSS THE CONUS. THIS BACKS OUR FLOW ALOFT FURTHER TO THE
SW AND OPENS THE DOOR FOR A FEED OF EVEN DEEPER AND TROPICAL-LIKE
MOISTURE TO MOVE IN. PWATS CLIMB TO NEAR 2 STANDARD DEVIATIONS ABOVE
NORMAL...AROUND 1.6 TO 1.7 INCHES SO YET ANOTHER ROUND OF RAINFALL
WILL OCCUR. POPS WILL BE IN THE CHANCE TO LIKELY RANGE MONDAY NIGHT
THEN SHOULD PEAK IN THE CATEGORICAL RANGE TUESDAY. ADDITIONAL QPF
WILL BE AT LEAST 1/2 TO 3/4 INCHES...WITH POTENTIAL HIGHER AMOUNTS
IN THIS PATTERN. THE SHORT WAVE IN THE PLAINS WILL ALSO TRIGGER
CYCLOGENESIS NEAR THE ARKLATEX REGION BY TUESDAY...WHICH IN TURN
ATTEMPTS TO LIFT OUR COASTAL WARM FRONT NORTHWARD. NOT SURE HOW THIS
PROGRESSION WILL ACTUAL PAN OUT GIVEN THAT THE INLAND WEDGE WILL BE
RELUCTANT TO GIVE UP ITS HOLD. THIS WILL ALLOW FOR WARM ADVECTION TO
BOOST TEMPS AT LEAST INTO THE LOWER OR MIDDLE 60S...PERHAPS EVEN
HIGHER NEAR THE ALTAMAHA. THIS IN TURN CREATES SOME SURFACE BASED
INSTABILITY ON THE ORDER OF 500-800 J/KG IN SYNC WITH STEEP MID
LEVEL LAPSE RATES OVER OUR COASTAL ZONES AND SOUTH OF I-16. IT/S IN
THESE AREAS WHERE WE HAVE ISOLATED T-STORMS MENTIONED IN THE LATEST
FORECAST.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT TEMPS WILL REMAIN RATHER MILD AHEAD OF A COLD FRONT TO
THE WEST. WE COULD SEE A FEW THUNDERSTORMS BEFORE THE FRONT SHIFTS
OFFSHORE WEDNESDAY AFTERNOON. GUSTY WINDS SHOULD ALSO ACCOMPANY THE
FRONT AS STRONG COLD AIR ADVECTION OCCURS BEHIND IT. A MUCH
QUIETER/DRY PERIOD OF WEATHER IS THEN ANTICIPATED AS HIGH PRESSURE
BUILDS OVER THE REGION BEHIND THE FRONT STARTING WEDNESDAY NIGHT.
TEMPS WILL BE SLOW TO WARM THROUGH THURSDAY...UNTIL HIGH PRESSURE
BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. OVERALL HIGH TEMPS
SHOULD RANGE IN THE MID/UPPER 50S THURSDAY...BEFORE SOUTHERLY FLOW
RETURNS TO THE AREA ALONG THE WESTERN EDGE OF HIGH PRESSURE ON
FRIDAY. TEMPS SHOULD PEAK INTO THE LOW/MID 60S BY LATE WEEK. ANOTHER
COLD FRONT COULD APPROACH NEXT WEEKEND...BRINGING THE NEXT CHANCE OF
PRECIP TO THE AREA.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
DO NOT EXPECTED IMPROVEMENT BEYOND MVFR CEILINGS TONIGHT AND
SUNDAY...AND IFR/LIFR CEILINGS WILL PREVAIL MUCH OF THE TIME THIS
EVENING INTO SUNDAY MORNING. PREVALENCE OF LIGHT RAIN REMAINS
SOMEWHAT UNCERTAIN AS ADDITIONAL WAVES PUSH E/NE INTO THE REGION
OVERNIGHT AND AGAIN SUNDAY. HIGHEST POPS SHOULD OCCUR AT KSAV
TONIGHT...ALTHOUGH RAIN COULD EXPAND INTO THE KCHS AREA. EVEN IF A
BREAK IN PRECIPITATION DEVELOPS LATE TONIGHT INTO SUNDAY MORNING...
ANOTHER ROUND OF RAIN SHOULD COMMENCE AT BOTH SITES SUNDAY
AFTERNOON.

EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR OR LOWER CONDITIONS
ARE LIKELY WITH RAIN/SHOWERS AND LOW STRATUS THROUGH EARLY TUESDAY
WHILE A WEDGE OF HIGH PRESSURE PERSISTS INLAND AND WAVES OF LOW
PRESSURE LIFT NORTHEAST ACROSS THE NEARBY ATLANTIC. ADDITIONAL
FLIGHT RESTRICTIONS APPEAR LIKELY TUESDAY AFTERNOON THROUGH
WEDNESDAY AFTERNOON AS A STRONG COLD FRONT APPROACHES FROM THE
WEST WITH SHOWERS AND POSSIBLY THUNDERSTORMS. WINDY CONDITIONS
SHOULD ALSO OCCUR NEAR THE TIME OF FRONTAL PASSAGE ON WEDNESDAY.

&&

.MARINE...
OVERNIGHT...MARINE LAYER MIXING AND A TIGHT SURFACE PRESSURE
GRADIENT BETWEEN AN INLAND WEDGE OF HIGH PRESSURE AND A TROUGH OF
LOW PRESSURE OVER THE GULF STREAM WILL MAINTAIN ELEVATED NORTHEAST
WINDS...AS HIGH AS 15-20 KT...AND ASSOCIATED SEAS 3-5 FT...HIGHEST
BEYOND 20 NM. OVERALL...WINDS/SEAS ARE EXPECTED TO REMAIN JUST
BELOW SMALL CRAFT ADVISORY LEVELS.

SUNDAY...A PINCHED PRESSURE GRADIENT BETWEEN DEVELOPING LOW PRESSURE
OFF THE GA COAST NEAR THE GULF STREAM AND A STRONG INLAND WEDGE OF
HIGH PRESSURE WILL PERSIST. THIS WILL RESULT IN NORTH/NE WINDS OF AT
LEAST 15-20 KT...WITH GUSTS AT TIMES TO NEAR 25 KT. IF THE GUSTS
BECOME FREQUENT ENOUGH WE/D NEED A SMALL CRAFT ADVISORY...WHICH
WE/LL DEFER TO FUTURE SHIFTS TO SEE IF WE INDEED SHOULD HOIST THE
ADVISORY HEADLINE. THE FETCH IS FAVORABLE ENOUGH FOR SEAS TO BE AS
HIGH AS 3-5 FT...GREATEST OVER AMZ374 AND THE EASTERNMOST PARTS OF
AMZ350.

SUNDAY NIGHT AND MONDAY...THE ATLANTIC WAVE DEEPENS SOME AS IT LIFTS
NE ALONG THE GULF STREAM...WHILE THE INLAND WEDGE HOLDS FIRM. THE
GRADIENT THOUGH DOES SLACKEN SOME OF THE LOW SHIFTS NORTH OF THE
LOCAL WATERS...AND WINDS AND SEAS WILL BE LESS AND BELOW ANY
ADVISORY CRITERIA.

MONDAY NIGHT AND TUESDAY...THE INLAND WEDGE IS STILL IN PLACE DURING
MUCH OF THE PERIOD...BUT IT DOES ATTEMPT TO ERODE BY TUESDAY NIGHT
AS THE COASTAL WARM FRONT STARTS TO LIFT NORTH/NW. UNTIL THIS
TRANSITION THOUGH OUR WINDS WILL STRUGGLE TO VEER AROUND...AS SPEEDS
HOLD NEAR OR BELOW 15 KT AND SEAS ARE LIMITED TO 3 OR 4 FT.

TUESDAY NIGHT AND WEDNESDAY...FINALLY THE COASTAL WARM FRONT WILL
SHIFT NORTH OF THE LOCAL WATERS TUESDAY NIGHT AS A STRONG COLD FRONT
MOVES THROUGH WEDNESDAY. WARM ADVECTION AND THE RESULTING
MARINE-LAYERING EFFECTS WILL LIMIT THE STRENGTH OF WINDS AHEAD OF
THE FRONT...BUT SMALL CRAFT ADVISORIES ARE CERTAINLY POSSIBLE.
BEHIND THE FRONT THE COMBINATION OF COLD ADVECTION AND STRONG
ISALLOBARIC PRESSURE RISES MAY SUPPORT GALES...OR AT THE LEAST SMALL
CRAFT ADVISORIES. MARINERS ARE ALSO ADVISED THAT SOME STRONGER
T-STORMS ARE POSSIBLE IN ADVANCE OF THE COLD FRONT...CAPABLE OF
PRODUCING GUSTY WINDS AND LIGHTNING STRIKES.

THURSDAY...CONDITIONS WILL IMPROVE OVER ALL WATERS AS HIGH PRESSURE
BECOMES CENTERED JUST SOUTH OF THE AREA. WINDS/SEAS SHOULD
EVENTUALLY LOWER BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL MARINE
ZONES AS COLD ADVECTION WANES AND THE GRADIENT RELAXES.

SEA FOG...LOW STRATUS DECKS COULD EQUATE TO REDUCED VISIBILITIES
INTO TUESDAY. ACTUAL SEA FOG MAY HAVE A WINDOW TO DEVELOP AS
SLIGHTLY WARMER AIR ARRIVES ATOP MID/UPPER 50 SHELF WATER TEMPS
WITHIN A SOUTH AND SOUTHWEST FLOW LATE TUESDAY INTO TUESDAY NIGHT
PRIOR TO WINDS INCREASING ENOUGH TO SCOUR IT OUT WEDNESDAY. NIGHT.

&&

.TIDES/COASTAL FLOODING...
ALTHOUGH THERE ARE NO IMMEDIATE CONCERNS IN REGARDS TO TIDES...GIVEN
THE PERIGEAN SPRING TIDES EARLY NEXT WEEK...THERE IS AN INCREASING
RISK FOR SHALLOW COASTAL FLOODING MONDAY AND TUESDAY AROUND THE TIME
OF THE MORNING HIGH TIDE. THIS SITUATION MIGHT BE FURTHER EXACERBATED
DUE TO STEADY RAINS PRIOR TO AND DURING THE HIGH TIDAL CYCLE.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...SPR
SHORT TERM...33
LONG TERM...DPB
AVIATION...33/SPR
MARINE...33/SPR
TIDES/COASTAL FLOODING...







AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 916 PM CST SAT DEC 20 2014

.UPDATE...
904 PM CST

WE STILL HAVE THE POSSIBILITY OF PATCHY FREEZING DRIZZLE
OVERNIGHT WITH THE BEST CHANCE IN OUR WESTERN AREAS.  THAT
SAID...TEMPERATURES ARE AROUND FREEZING AND NOT EXPECTED TO DROP
MUCH GIVEN THE CLOUD COVER AND WARM ADVECTION PATTERN SETTING UP.
AT THIS POINT IMPACTS DO LOOK MINIMAL...ESPECIALLY FARTHER EAST.  HAVE
KEPT TEMPS NEARLY STEADY OVERNIGHT. SOME PRECIPITATION MAY MAKE IT
CLOSER TO CHICAGO LATE TONIGHT INTO SUNDAY MORNING ONCE THE WARM
FRONT GETS CLOSER...BUT IT WOULD BE LARGELY IN THE FORM OF PATCHY
DRIZZLE. FOG MAY BE POSSIBLE AS WELL OVERNIGHT.

KMD

&&

.SHORT TERM...
247 PM CST

THROUGH SUNDAY NIGHT...

THE STREAK OF CLOUDY DAYS CONTINUES...WITH THE STUBBORN PATTERN TO
CONTINUE. AS A RESULT OF THE THICK CLOUD COVER...AND LACK OF
ORGANIZED ADVECTION OF ANY WARMER AIR AT THE SFC...TEMPS HAVE HELD
MAINLY ARND 30 TO 35 ACROSS THE BULK OF THE CWFA. SFC RIDGE
CONTINUES TO DRIFT EAST THIS AFTN...WITH A WEAK SOUTHERLY FLOW
DEVELOPING. THERE WAS A WEAK MID-LVL VORT LIFTING NORTHEAST ACROSS
SOUTHERN WISC/WESTERN LOWER MI...WHICH WAS ABLE TO PRODUCE A FEW
FLURRIES ACROSS THE FAR NORTHERN IL AREAS.

THIS AFTN/EARLY EVE LOOKS TO REMAIN QUIET/DRY...WITH A LIGHT
SOUTH/SOUTHEAST WIND. IR IMAGERY SHOWS THE NEXT WAVE ACROSS THE
CENTRAL PLAINS...WHICH IS PROGGED TO ARRIVE ACROSS NORTHWEST IL
AFTER MIDNIGHT. THERE APPEARS TO BE SOME WEAK ADVECTION OF MOISTURE
IN THE LOW-LEVELS OVERNIGHT. SOUNDINGS SUGGEST A NARROW WARM WEDGE
ALOFT WHICH COULD TRANSITION ANY PRECIP OVERNIGHT TO LIQUID. THE
FORCING/OMEGA IS RATHER WEAK...WHICH MAY LIMIT DROPLET SIZE AND
RESULT IN JUST PATCHY FREEZING DRIZZLE. TEMPS WILL LIKELY NOT MOVE
MUCH OVERNIGHT...SO HAVE HELD ONTO MID/UPR 20S OVERNIGHT.

LOCAL ARW8KM SOLUTION INDICATES THE MOISTURE TO BE RATHER MARGINAL
WITH THE SYSTEM ARRIVING OVERNIGHT/SUN MORNING...BUT PROGRESSIVE AND
LIFTING NORTH OF THE CWFA BY MIDDAY. WEAK THERMAL RIDGE AT 850MB
WOULD SUGGEST TEMPS MAY ACTUALLY WARM SUN AFTN...HOWEVER GIVEN THE
STUBBORN PATTERN WE HAVE BEEN IN WOULD LEAN TOWARDS NUDGING TEMPS
DOWN A DEGREE OR TWO. MOISTURE LAYER WILL REMAIN LOCKED IN ACROSS
THE REGION THRU SUN/SUN NGT. WITH A CONTINUED SOUTHERLY FLOW AT THE
SFC...TEMPS WILL LIKELY ONLY FALL TO ARND 30/LOW 30S.

BEACHLER

&&

.LONG TERM...
247 PM CST

MONDAY THROUGH SATURDAY...

500MB TROUGH BEGINS TO DIG INTO THE CENTRAL CONUS MON MORNING...WITH
WARM AIR STEADILY ADVECTING NORTH ACROSS THE FORECAST AREA. WHILE
THE THICK CLOUD COVER WILL PERSIST...THE PUSH OF WARM/MOIST AIR WILL
BRING TEMPS INTO THE 40S THE FAR SOUTHERN CWFA COULD SEE A FEW
LOCATIONS TOUCH THE UPR 40S MON AFTN. PRECIP WILL STEADILY PUSH EAST
AS THE UPPER LEVEL SYSTEM PROGRESSES TOWARDS THE REGION...BUT WITH
THE WARM AIR IN PLACE PRECIP SHUD FALL AS RAIN.

MON NGT THE 500MB VORT WILL SLIDE INTO THE UPPER MIDWEST...BUT THE
TROUGH WILL DIG SOUTH ACROSS THE SOUTHERN PLAINS. GUIDANCE HAS BEEN
INDICATING A SECONDARY SHORTWAVE EJECTING FROM THE TROUGH AXIS...AND
LIFTING IT NORTHEAST ACROSS THE TENN VALLEY CHRISTMAS EVE. THE
NORTHERN SFC LOW WILL BE WRAPPED UP ACROSS CENTRAL WISC TUE...WITH
THE MOIST CHANNEL FEEDING NORTH ACROSS THE FORECAST AREA THRU TUE
AFTN. THE SOUTHERN LOW WILL BE QUICKLY DEEPENING AS IT LIFTS NORTH
ACROSS THE OHIO VALLEY WED MORNING...ALLOWING WINDS TO BE ON THE
INCREASE AND HELPING TO STEADILY TRANSITION PRECIP OVER FROM RAIN TO
SNOW POST FROPA WED MORNING.

THE LAST SEVERAL CYCLES OF GUIDANCE HAVE DEMONSTRATED DIFFERENCES IN
PLACEMENT/TRACK OF THE SFC LOW WED AFTN/EVE. LATEST SOLUTION IS
PROGGED TO LIFT NORTH ACROSS NORTHERN IN AND THEN SLIGHTLY
RETROGRADE ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN WED EVE. THEN BY
CHRISTMAS DAY THE TROUGH WILL BE PIVOTING EAST AND HELPING TO LIFT
THE SFC LOW NORTHEAST AWAY FROM THE REGION. SOME WRAP AROUND
MOISTURE/SNOW LOOKS FAVORABLE WED NGT/THUR MORNING...BEFORE COMING
TO AN END JUST AFTER DAYBREAK CHRISTMAS MORNING. THIS SYSTEM WILL
CONTINUE TO BE CLOSELY MONITORED.

TEMPS WILL BE RETURNING TO MORE SEASONAL CONDS...WITH HIGHS
CHRISTMAS DAY IN THE LOW/MID 30S. FLOW REMAINS RATHER PROGRESSIVE
WITH ANOTHER WEAK PUSH OF WARMER AIR RETURNING FRI AND TEMPS BACK TO
THE UPR 30S/LOW 40S. THEN FOR FRI ENSEMBLES ARE INDICATING YET
ANOTHER TROUGH BEGINNING TO DIG INTO THE CENTRAL CONUS...WITH A SFC
LOW LIFTING NORTHEAST ACROSS THE WESTERN GREAT LAKES.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* CIGS LOWER TO MVFR LATER TONIGHT AND POTENTIALLY TO IFR SUNDAY
* SLIGHT CHANCE OF -FZDZ OR -DZ SUNDAY MORNING

IZZI

//DISCUSSION...UPDATED 00Z...

HAVE LARGELY FOLLOWED THE TRENDS FROM PREVIOUS SET OF TAFS WITH
LOWERING CIGS TONIGHT/SUNDAY...THOUGH HAVE SPED UP THE ARRIVAL OF
MVFR CIGS TONIGHT AND LOWERED CIGS A BIT SUNDAY. EXPANSIVE AREA OF
IFR/BR/-DZ BLANKETS IOWA AND SHOULD SLOWLY SPREAD EASTWARD THROUGH
THE PERIOD. ONLY BRINGING CIGS DOWN TO LOWER END MVFR SUNDAY COULD
END UP BEING TOO OPTIMISTIC FOR ORD/MDW/GYY...WILL MONITOR TRENDS
IN THE EASTWARD EXPANSION OF IFR/LIFR TONIGHT AND WE MAY NEED TO
ADD IFR INTO THE TAFS FOR CHICAGO TERMINALS IN LATER FORECASTS. AS
WELL...IF CIGS DO DROP LOWER THEN POTENTIAL WOULD BE GREATER FOR
SOME -FZDZ TRANSITIONING TO -DZ AS TEMPS INCH UPWARD. NOT
ANTICIPATING CIGS TO LIFT MUCH FROM MORNING LOWS SUNDAY...SO IFE
CONDITIONS DEVELOP THEY COULD PERSIST THROUGH THE DAY. CERTAINLY
COULD SEE SOME OCNL GUSTS OF 15-20KT SUNDAY AFTERNOON FROM THE
SSE...BUT THINKING THE EXPECTED STRATUS DECK SHOULD LIMIT MIXING
ENOUGH TO KEEP GUSTINESS SPORADIC TO OCNL AT BEST.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH SUNDAY MORNING...LOW
  CONFIDENCE IN TIMING AND HOW LOW CIGS GET
* LOW CONFIDENCE IN CIGS SUNDAY AFTERNOON
* LOW CONFIDENCE IN DZ/FZDZ POTENTIAL SUNDAY MORNING
* MEDIUM-HIGH CONFIDENCE IN WINDS

IZZI

//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...

MONDAY...MVFR/IFR EARLY LOWERING TO IFR/LIFR. RAIN DEVELOPING
LATE.

TUESDAY...ONCL SHRA. IFR PROBABLE.

WEDNESDAY...CHANCE SHRA/SHSN. MVFR LIKELY. IFR POSSIBLE.

THURSDAY...MVFR CIGS POSSIBLE EARLY.

FRIDAY...CHANCE OF RA/SN LATE. MVFR CIGS POSSIBLE AGAIN.

IZZI

&&

.MARINE...
203 PM CST

LIGHT SOUTHEAST TO EAST WINDS WILL INCREASE TO 10-25 KT TOMORROW
MORNING THEN TO 30 KT IN THE AFTERNOON AS THE GRADIENT TIGHTENS
BETWEEN THE DEPARTING HIGH AND THE NEXT LOW. THE LOW MOVES OVER THE
DAKOTAS SUNDAY NIGHT AND MODELS AGREE A BIT MORE IN THE PATTERN
EARLY NEXT WEEK.  HAVE MEDIUM CONFIDENCE IN THE WIND FORECAST WITH
THIS NEXT LOW.  THE LOW WEAKENS AS IT MOVES OVER WISCONSIN TUESDAY
AND A SECOND LOW FORMS OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY
AFTERNOON. THE SECOND LOW WILL RACE NORTH AND DEEPEN REACHING
MICHIGAN WEDNESDAY. MODELS DIFFER ON HOW QUICKLY THE LOW WILL REACH
MICHIGAN.  BOTH MODELS CONTINUE TO FEATURE WESTERLY HIGH END GALES
BEHIND THE LOW WEDNESDAY AFTERNOON INTO THURSDAY.  WEST WINDS
DIMINISH THURSDAY AS THE LOW CONTINUES OFF TO THE NORTH. THE NEXT
LOW MOVES OVER THE SOUTHERN PLAINS THURSDAY AFTERNOON. GUIDANCE
DIFFERS ON THIS LOWS PATH BUT IT SHOULD IMPACT THE LAKE LATE NEXT
WEEK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




  [top]

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
857 PM CST Sat Dec 20 2014

.UPDATE...
ISSUED AT 857 PM CST SAT DEC 20 2014

Clouds cover most of the CWA tonight, but a small area in the east
and southeast is clear at the moment. Expect this area to cloud
over overnight. However, need to make some adjustments to the
cloud cover grids tonight. Remainder of grids look ok. Will send
an update on the forecast, but will not be a change for most of
the area. Changes will be in the east and southeast only.

&&

.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST SAT DEC 20 2014

Cloudy skies persist across much of central Illinois this afternoon:
however, 20z/2pm visible satellite imagery shows a large tear in the
overcast developing from near Decatur southeastward to Flora.
Although the HRRR has been a bit overdone with the clearing, it
continues to suggest at least thinning clouds across the E/SE KILX
CWA late this afternoon into the evening.  In fact, with 925mb winds
remaining light/variable and not really picking up a strong S/SW
component until Sunday, portions of the SE may see partly cloudy
conditions persist through the night.  Further north and west, low
clouds will be on the increase from the west.  Forecast soundings
and model RH profiles indicate that the lowest clouds/fog will
remain just W/NW of central Illinois tonight.  Due to cloud cover
and a light S/SE wind, low temperatures will be a couple of degrees
warmer than last night.  Coolest readings in the middle 20s will
occur south of I-70 where skies will likely remain partly cloudy,
while lows stay in the upper 20s/lower 30s elsewhere.

&&

.LONG TERM...(Sunday through Saturday)
ISSUED AT 259 PM CST SAT DEC 20 2014

Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.

High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.

Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.

The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.

Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 534 PM CST SAT DEC 20 2014

Clouds will continue across all TAF sites next 24hrs. Believe MVFR
cigs will dominate the sites next 24hrs. However, VFR cigs are
occurring at PIA, SPI and CMI to start; but expecting them to drop
into MVFR category shortly. So, will have all starting at MVFR and
have a 3hr TEMPO group at all sites for VFR cigs. Remainder of the
night will see cigs drop to below 2kft but then improve to above
2kft tomorrow afternoon. All still remaining in the MVFR category.
Winds will be light south-southeast overnight and then become
southerly around 10kts tomorrow afternoon.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 559 PM CST SAT DEC 20 2014

.SHORT TERM...
247 PM CST

THROUGH SUNDAY NIGHT...

THE STREAK OF CLOUDY DAYS CONTINUES...WITH THE STUBBORN PATTERN TO
CONTINUE. AS A RESULT OF THE THICK CLOUD COVER...AND LACK OF
ORGANIZED ADVECTION OF ANY WARMER AIR AT THE SFC...TEMPS HAVE HELD
MAINLY ARND 30 TO 35 ACROSS THE BULK OF THE CWFA. SFC RIDGE
CONTINUES TO DRIFT EAST THIS AFTN...WITH A WEAK SOUTHERLY FLOW
DEVELOPING. THERE WAS A WEAK MID-LVL VORT LIFTING NORTHEAST ACROSS
SOUTHERN WISC/WESTERN LOWER MI...WHICH WAS ABLE TO PRODUCE A FEW
FLURRIES ACROSS THE FAR NORTHERN IL AREAS.

THIS AFTN/EARLY EVE LOOKS TO REMAIN QUIET/DRY...WITH A LIGHT
SOUTH/SOUTHEAST WIND. IR IMAGERY SHOWS THE NEXT WAVE ACROSS THE
CENTRAL PLAINS...WHICH IS PROGGED TO ARRIVE ACROSS NORTHWEST IL
AFTER MIDNIGHT. THERE APPEARS TO BE SOME WEAK ADVECTION OF MOISTURE
IN THE LOW-LEVELS OVERNIGHT. SOUNDINGS SUGGEST A NARROW WARM WEDGE
ALOFT WHICH COULD TRANSITION ANY PRECIP OVERNIGHT TO LIQUID. THE
FORCING/OMEGA IS RATHER WEAK...WHICH MAY LIMIT DROPLET SIZE AND
RESULT IN JUST PATCHY FREEZING DRIZZLE. TEMPS WILL LIKELY NOT MOVE
MUCH OVERNIGHT...SO HAVE HELD ONTO MID/UPR 20S OVERNIGHT.

LOCAL ARW8KM SOLUTION INDICATES THE MOISTURE TO BE RATHER MARGINAL
WITH THE SYSTEM ARRIVING OVERNIGHT/SUN MORNING...BUT PROGRESSIVE AND
LIFTING NORTH OF THE CWFA BY MIDDAY. WEAK THERMAL RIDGE AT 850MB
WOULD SUGGEST TEMPS MAY ACTUALLY WARM SUN AFTN...HOWEVER GIVEN THE
STUBBORN PATTERN WE HAVE BEEN IN WOULD LEAN TOWARDS NUDGING TEMPS
DOWN A DEGREE OR TWO. MOISTURE LAYER WILL REMAIN LOCKED IN ACROSS
THE REGION THRU SUN/SUN NGT. WITH A CONTINUED SOUTHERLY FLOW AT THE
SFC...TEMPS WILL LIKELY ONLY FALL TO ARND 30/LOW 30S.

BEACHLER

&&

.LONG TERM...
247 PM CST

MONDAY THROUGH SATURDAY...

500MB TROUGH BEGINS TO DIG INTO THE CENTRAL CONUS MON MORNING...WITH
WARM AIR STEADILY ADVECTING NORTH ACROSS THE FORECAST AREA. WHILE
THE THICK CLOUD COVER WILL PERSIST...THE PUSH OF WARM/MOIST AIR WILL
BRING TEMPS INTO THE 40S THE FAR SOUTHERN CWFA COULD SEE A FEW
LOCATIONS TOUCH THE UPR 40S MON AFTN. PRECIP WILL STEADILY PUSH EAST
AS THE UPPER LEVEL SYSTEM PROGRESSES TOWARDS THE REGION...BUT WITH
THE WARM AIR IN PLACE PRECIP SHUD FALL AS RAIN.

MON NGT THE 500MB VORT WILL SLIDE INTO THE UPPER MIDWEST...BUT THE
TROUGH WILL DIG SOUTH ACROSS THE SOUTHERN PLAINS. GUIDANCE HAS BEEN
INDICATING A SECONDARY SHORTWAVE EJECTING FROM THE TROUGH AXIS...AND
LIFTING IT NORTHEAST ACROSS THE TENN VALLEY CHRISTMAS EVE. THE
NORTHERN SFC LOW WILL BE WRAPPED UP ACROSS CENTRAL WISC TUE...WITH
THE MOIST CHANNEL FEEDING NORTH ACROSS THE FORECAST AREA THRU TUE
AFTN. THE SOUTHERN LOW WILL BE QUICKLY DEEPENING AS IT LIFTS NORTH
ACROSS THE OHIO VALLEY WED MORNING...ALLOWING WINDS TO BE ON THE
INCREASE AND HELPING TO STEADILY TRANSITION PRECIP OVER FROM RAIN TO
SNOW POST FROPA WED MORNING.

THE LAST SEVERAL CYCLES OF GUIDANCE HAVE DEMONSTRATED DIFFERENCES IN
PLACEMENT/TRACK OF THE SFC LOW WED AFTN/EVE. LATEST SOLUTION IS
PROGGED TO LIFT NORTH ACROSS NORTHERN IN AND THEN SLIGHTLY
RETROGRADE ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN WED EVE. THEN BY
CHRISTMAS DAY THE TROUGH WILL BE PIVOTING EAST AND HELPING TO LIFT
THE SFC LOW NORTHEAST AWAY FROM THE REGION. SOME WRAP AROUND
MOISTURE/SNOW LOOKS FAVORABLE WED NGT/THUR MORNING...BEFORE COMING
TO AN END JUST AFTER DAYBREAK CHRISTMAS MORNING. THIS SYSTEM WILL
CONTINUE TO BE CLOSELY MONITORED.

TEMPS WILL BE RETURNING TO MORE SEASONAL CONDS...WITH HIGHS
CHRISTMAS DAY IN THE LOW/MID 30S. FLOW REMAINS RATHER PROGRESSIVE
WITH ANOTHER WEAK PUSH OF WARMER AIR RETURNING FRI AND TEMPS BACK TO
THE UPR 30S/LOW 40S. THEN FOR FRI ENSEMBLES ARE INDICATING YET
ANOTHER TROUGH BEGINNING TO DIG INTO THE CENTRAL CONUS...WITH A SFC
LOW LIFTING NORTHEAST ACROSS THE WESTERN GREAT LAKES.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* CIGS LOWER TO MVFR LATER TONIGHT AND POTENTIALLY TO IFR SUNDAY
* SLIGHT CHANCE OF -FZDZ OR -DZ SUNDAY MORNING

IZZI

//DISCUSSION...UPDATED 00Z...

HAVE LARGELY FOLLOWED THE TRENDS FROM PREVIOUS SET OF TAFS WITH
LOWERING CIGS TONIGHT/SUNDAY...THOUGH HAVE SPED UP THE ARRIVAL OF
MVFR CIGS TONIGHT AND LOWERED CIGS A BIT SUNDAY. EXPANSIVE AREA OF
IFR/BR/-DZ BLANKETS IOWA AND SHOULD SLOWLY SPREAD EASTWARD THROUGH
THE PERIOD. ONLY BRINGING CIGS DOWN TO LOWER END MVFR SUNDAY COULD
END UP BEING TOO OPTIMISTIC FOR ORD/MDW/GYY...WILL MONITOR TRENDS
IN THE EASTWARD EXPANSION OF IFR/LIFR TONIGHT AND WE MAY NEED TO
ADD IFR INTO THE TAFS FOR CHICAGO TERMINALS IN LATER FORECASTS. AS
WELL...IF CIGS DO DROP LOWER THEN POTENTIAL WOULD BE GREATER FOR
SOME -FZDZ TRANSITIONING TO -DZ AS TEMPS INCH UPWARD. NOT
ANTICIPATING CIGS TO LIFT MUCH FROM MORNING LOWS SUNDAY...SO IFE
CONDITIONS DEVELOP THEY COULD PERSIST THROUGH THE DAY. CERTAINLY
COULD SEE SOME OCNL GUSTS OF 15-20KT SUNDAY AFTERNOON FROM THE
SSE...BUT THINKING THE EXPECTED STRATUS DECK SHOULD LIMIT MIXING
ENOUGH TO KEEP GUSTINESS SPORADIC TO OCNL AT BEST.

IZZI


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH SUNDAY MORNING...LOW
  CONFIDENCE IN TIMING AND HOW LOW CIGS GET
* LOW CONFIDENCE IN CIGS SUNDAY AFTERNOON
* LOW CONFIDENCE IN DZ/FZDZ POTENTIAL SUNDAY MORNING
* MEDIUM-HIGH CONFIDENCE IN WINDS

IZZI

//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...

MONDAY...MVFR/IFR EARLY LOWERING TO IFR/LIFR. RAIN DEVELOPING
LATE.

TUESDAY...ONCL SHRA. IFR PROBABLE.

WEDNESDAY...CHANCE SHRA/SHSN. MVFR LIKELY. IFR POSSIBLE.

THURSDAY...MVFR CIGS POSSIBLE EARLY.

FRIDAY...CHANCE OF RA/SN LATE. MVFR CIGS POSSIBLE AGAIN.

IZZI

&&

.MARINE...
203 PM CST

LIGHT SOUTHEAST TO EAST WINDS WILL INCREASE TO 10-25 KT TOMORROW
MORNING THEN TO 30 KT IN THE AFTERNOON AS THE GRADIENT TIGHTENS
BETWEEN THE DEPARTING HIGH AND THE NEXT LOW. THE LOW MOVES OVER THE
DAKOTAS SUNDAY NIGHT AND MODELS AGREE A BIT MORE IN THE PATTERN
EARLY NEXT WEEK.  HAVE MEDIUM CONFIDENCE IN THE WIND FORECAST WITH
THIS NEXT LOW.  THE LOW WEAKENS AS IT MOVES OVER WISCONSIN TUESDAY
AND A SECOND LOW FORMS OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY
AFTERNOON. THE SECOND LOW WILL RACE NORTH AND DEEPEN REACHING
MICHIGAN WEDNESDAY. MODELS DIFFER ON HOW QUICKLY THE LOW WILL REACH
MICHIGAN.  BOTH MODELS CONTINUE TO FEATURE WESTERLY HIGH END GALES
BEHIND THE LOW WEDNESDAY AFTERNOON INTO THURSDAY.  WEST WINDS
DIMINISH THURSDAY AS THE LOW CONTINUES OFF TO THE NORTH. THE NEXT
LOW MOVES OVER THE SOUTHERN PLAINS THURSDAY AFTERNOON. GUIDANCE
DIFFERS ON THIS LOWS PATH BUT IT SHOULD IMPACT THE LAKE LATE NEXT
WEEK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
534 PM CST Sat Dec 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST SAT DEC 20 2014

Cloudy skies persist across much of central Illinois this afternoon:
however, 20z/2pm visible satellite imagery shows a large tear in the
overcast developing from near Decatur southeastward to Flora.
Although the HRRR has been a bit overdone with the clearing, it
continues to suggest at least thinning clouds across the E/SE KILX
CWA late this afternoon into the evening.  In fact, with 925mb winds
remaining light/variable and not really picking up a strong S/SW
component until Sunday, portions of the SE may see partly cloudy
conditions persist through the night.  Further north and west, low
clouds will be on the increase from the west.  Forecast soundings
and model RH profiles indicate that the lowest clouds/fog will
remain just W/NW of central Illinois tonight.  Due to cloud cover
and a light S/SE wind, low temperatures will be a couple of degrees
warmer than last night.  Coolest readings in the middle 20s will
occur south of I-70 where skies will likely remain partly cloudy,
while lows stay in the upper 20s/lower 30s elsewhere.

&&

.LONG TERM...(Sunday through Saturday)
ISSUED AT 259 PM CST SAT DEC 20 2014

Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.

High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.

Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.

The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.

Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 534 PM CST SAT DEC 20 2014

Clouds will continue across all TAF sites next 24hrs. Believe MVFR
cigs will dominate the sites next 24hrs. However, VFR cigs are
occurring at PIA, SPI and CMI to start; but expecting them to drop
into MVFR category shortly. So, will have all starting at MVFR and
have a 3hr TEMPO group at all sites for VFR cigs. Remainder of the
night will see cigs drop to below 2kft but then improve to above
2kft tomorrow afternoon. All still remaining in the MVFR category.
Winds will be light south-southeast overnight and then become
southerly around 10kts tomorrow afternoon.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 150 PM CST FRI DEC 19 2014

.SHORT TERM...
259 AM CST

THROUGH SUNDAY...

THE MAIN CONCERNS DURING THE SHORT TERM WILL BE SOME PERIODIC
CHANCES OF VERY LIGHT SNOW OR DRIZZLE THROUGH THE WEEKEND AS SEVERAL
WEAK...AND FAST MOVING MID LEVEL DISTURBANCES SHIFT ACROSS THE AREA.

SURFACE HIGH PRESSURE IS CENTERED ACROSS MUCH OF THE MID AND UPPER
MISSISSIPPI RIVER VALLEY EARLY THIS MORNING. THIS FEATURE IS EXPECTED
TO REMAIN IN CONTROL ACROSS NORTHERN ILLINOIS DURING THE DAY TODAY.
OVERALL...WHICH WILL RESULT IN A VERY LIGHT AND VARIABLE WIND
FIELD ACROSS THE AREA TODAY. AN AREA OF LAKE EFFECT FLURRIES
CONTINUES ACROSS PORTIONS OF THE CHICAGO AREA...AND INTO
NORTHWESTERN INDIANA NEAR LAKE MICHIGAN. MODEL SOUNDINGS INDICATE
JUST DEEP ENOUGH INVERSION HEIGHTS TO SUPPORT ICE IN THE
CLOUDS...AND GIVEN MDW HAS BEEN REPORTING ONLY -SN FOR MOST OF THE
NIGHT IT APPEARS THE THREAT OF FREEZING DRIZZLE WILL BE LOW. ALL
OF THIS ACTIVITY SHOULD WANE ACROSS THE AREA DURING THE MORNING AS
THE WIND FIELD CONTINUES TO WEAKEN OVER SOUTH LAKE MICHIGAN IN
RESPONSE TO THE APPROACHING SURFACE RIDGE OF HIGH PRESSURE.

SURFACE WINDS WILL BEGIN TO SHIFT OUT OF THE SOUTH BY EARLY SATURDAY
MORNING AS THIS SURFACE HIGH BEGINS TO SHIFT EAST OF THE REGION. AS
THIS OCCURS...GUIDANCE IS INSISTENT WITH BRINGING A WEAK UPPER
DISTURBANCE ACROSS NORTHERN ILLINOIS SATURDAY MORNING. THIS WEAK
WAVE IS NOTED IN THE WATER VAPOR IMAGERY CURRENTLY ACROSS
SOUTHEASTERN ALBERTA. MOISTURE APPEARS TO REMAIN LIMITED WITH THIS
WAVE. HOWEVER...I THINK THIS WAVE...AND SOME WEAK ISENTROPIC ASCENT
COULD SQUEEZE OUT A FEW FLURRIES SATURDAY MORNING...SO I HAVE
INCLUDED A SLIGHT CHANCE FOR SUCH IN THE FORECAST.

WARM AIR ADVECTION/ISENTROPIC ASCENT WILL CONTINUE TO INCREASE
ACROSS MUCH OF THE MIDWEST AND GREAT LAKES REGION INTO SUNDAY IN
RESPONSE TO AN INCREASING SOUTHERLY WIND FIELD AHEAD OF A STORM
SYSTEM...WHICH IS EXPECTED TO DEVELOP ACROSS THE PLAINS. THIS COULD
AGAIN RESULT IN A PERIOD OF LIGHT PRECIP ACROSS MAINLY FAR NORTHERN
ILLINOIS VERY LATE SATURDAY NIGHT AND INTO SUNDAY.
OVERALL...CONFIDENCE IS LOW AS TO HOW FAR SOUTH THIS LIGHT PRECIP
WILL BE ABLE TO DEVELOP...BUT GIVEN THE POTENTIAL THAT IF THIS
PRECIP DOES DEVELOP AS FAR SOUTH AS NORTHERN ILLINOIS...THERE COULD
BE A PERIOD OF FREEZING DRIZZLE INTO EARLY SUNDAY MORNING BEFORE
TEMPERATURES JUMP ABOVE FREEZING...I HAVE OPTED TO INCLUDE A SLIGHT
MENTION LATE SATURDAY NIGHT INTO EARLY SUNDAY...MAINLY FOR AREAS
NORTH OF INTERSTATE 90.

KJB

&&

.LONG TERM...
259 AM CST

SUNDAY NIGHT THROUGH THURSDAY...

THE LONG TERM PERIOD WILL BE A PERIOD OF A SIGNIFICANT WEATHER
PATTERN SHIFT ACROSS NORTH AMERICA AND AS SUCH...IT APPEARS LIKELY
THAT THE CENTRAL CONUS WILL BECOME MUCH MORE ACTIVE INTO THE
HOLIDAY WEEK. THE MAIN CONCERNS LOCALLY WITH THIS PATTERN
SHIFT...WILL BE PRECIP TYPES...AND THE ACTUAL EVOLUTION
OF...POTENTIALLY A SIGNIFICANT STORM SYSTEM ACROSS PORTIONS OF THE
GREAT LAKES REGION CHRISTMAS EVE.

UNFORTUNATELY...THE DETAILS OF THIS STORM SYSTEM THIS FAR OUT ARE
STILL LARGELY UNCERTAIN...AS LARGE SCALE PATTERN SHIFTS SUCH AS THIS
TYPICAL RESULT IN LOWER PREDICTABILITY...ESPECIALLY WITH REGARDS TO
THE TRACK AND ACTUAL STRENGTH OF A DEVELOPING STORM SYSTEM. WHAT
APPEARS TO BE LIKELY...HOWEVER...IS FOR A PERIOD OF RAIN ACROSS THE
AREA LATE MONDAY AND MONDAY NIGHT AS WHAT APPEARS TO BE THE INITIAL
STORM SYSTEM...BEGINS TO SHIFT A WARM FRONT ACROSS NORTHERN
ILLINOIS. GIVEN THE WARM SECTOR PLACEMENT OF MY AREA...PRECIP TYPE
LOOKS TO BE LIQUID...WITH SURFACE TEMPERATURES LIKELY TO REMAIN
ABOVE FREEZING MONDAY NIGHT WITH CONTINUED SOUTHERN FLOW.

THE MAIN UNCERTAINTIES COME INTO PLAY BY CHRISTMAS EVE...AS MODEL
GUIDANCE CONTINUES TO ADVERTISE A SIGNIFICANT AMPLIFICATION TO THE
UPPER LEVEL PATTERN ACROSS THE EASTERN PACIFIC AND NORTH AMERICA. A
STRONG PACIFIC JET (NEAR 40 DEGREES N)...INITIALIZED AT OVER 180 KT
IN THIS EVENINGS MODEL OUTPUT IS FORECAST TO RESULT IN THE BUILDING
OF A POTENT UPPER RIDGE JUST OFF THE CALIFORNIA COAST BY EARLY NEXT
WEEK. TELECONNECTIONS RELATED TO SUCH PATTERN SHIFT CERTAINLY SUPPORT
THE DIGGING OF A SIGNIFICANT TROUGH...AND A GOOD POSSIBILITY OF AN
STORM SYSTEM ACROSS THE CENTRAL CONUS DURING THE UPCOMING HOLIDAY
WEEK. HOWEVER...AS PREVIOUSLY MENTIONED CONFIDENCE IS LOW WITH THE
DETAILS OF HOW AND WHERE EXACTLY THIS STORM MAY TRACK. THIS IS A
PERIOD WORTH WATCHING THOUGH...AS AT LEAST SOME SNOW AND POSSIBLY
STRONG NORTHWEST WINDS COULD BE IN STORE.

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* MVFR CIGS.

BMD

//DISCUSSION...UPDATED 18Z...

RELATIVELY UNCHANGING CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
THE TAF PERIOD WITH PRIMARILY MVFR CIGS AND LIGHT WINDS. WINDS THIS
AFTERNOON ARE GENERALLY 5 KT OR LESS AND OUT OF THE NORTH OR
NORTHWEST...BUT WILL LIKELY BECOME MORE VARIABLE AND POSSIBLY CALM
FOR A PERIOD THIS EVENING AND OVERNIGHT...BEFORE SOUTHERLY WINDS
START TO CREEP IN BEHIND THE HIGH TOMORROW. WHILE A FEW BREAKS IN
THE CLOUDS MAY DEVELOP...EXPECT MVFR CIGS TO GENERALLY REMAIN LOCKED
IN UNDER A STRONG INVERSION WITH SOME LOWERING OVERNIGHT.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* MEDIUM IN CIGS.
* HIGH IN REMAINING FORECAST ELEMENTS.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...

SATURDAY NIGHT...MVFR LIKELY. LIGHT SOUTH WINDS.

SUNDAY...SLGT CHANCE FLURRIES/FREEZING DRIZZLE EARLY. MVFR LIKELY.
SOUTH-SOUTHEAST WINDS.

MONDAY AND TUESDAY...CHANCE OF RAIN...ESPECIALLY MONDAY NIGHT. MVFR
LIKELY. SOUTHEAST WINDS MONDAY BECOMING SOUTHWEST TUESDAY.

WEDNESDAY...CHANCE OF SNOW. MVFR POSSIBLE. GUSTY WEST WINDS.

THURSDAY...DRY. VFR.

RATZER

&&

.MARINE...
156 AM CST

MAIN MARINE CONCERNS THIS MORNING ARE A PERIOD OF STRENGTHENING
SOUTH-SOUTHEAST WINDS LATE SUNDAY THROUGH MONDAY NIGHT...THEN THE
POTENTIAL FOR WEST GALES LATE WEDNESDAY INTO THURSDAY.

FAIRLY QUIET STRETCH OF WEATHER ACROSS LAKE MICHIGAN TODAY THROUGH
SATURDAY AS A LARGE AREA OF WEAK HIGH PRESSURE DRIFTS SLOWLY EAST
ACROSS THE REGION. LIGHT NORTH WINDS TODAY WILL BECOME SOMEWHAT
LIGHT/VARIABLE...BEFORE BECOMING LIGHT SOUTH ON SATURDAY AS THE
SURFACE RIDGE AXIS PASSES TO THE EAST. SOUTHERLY WINDS WILL THEN
BEGIN TO INCREASE SATURDAY NIGHT AND MORE SO SUNDAY...AS LOW
PRESSURE DEVELOPS IN THE LEE OF THE NORTHERN ROCKIES AND THE
GRADIENT BEGINS TO TIGHTEN ACROSS THE PLAINS AND UPPER MIDWEST.
MEDIUM RANGE FORECAST MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING
A SUB-1000 MB SURFACE LOW ACROSS IOWA OR SOUTHERN MINNESOTA BY
MIDDAY MONDAY...WHICH WOULD LEAD TO SOUTH-SOUTHEAST WINDS IN THE
20-25 KT RANGE THROUGH MONDAY BEFORE OCCLUDING AND WEAKENING AS THE
LOW MOVES ACROSS WISCONSIN AND LAKE MICHIGAN ON TUESDAY.

HOWEVER...VARIOUS MODEL AND MODEL ENSEMBLE MEMBERS THEN DEVELOP A
SECOND LOW SOUTH OF THE LAKES ALONG THE TRAILING COLD FRONT TUESDAY
NIGHT...WHICH WOULD LIFT NORTH AND COMBINE WITH THE FILLING GREAT
LAKES LOW...DEEPENING RAPIDLY WEDNESDAY AND WEDNESDAY NIGHT OVER THE
EASTERN LAKES. THIS SCENARIO WOULD LEAD TO QUICKLY INCREASING
WESTERLY WINDS ACROSS LAKE MICHIGAN...QUITE POSSIBLY WEST GALES...
LATE WEDNESDAY INTO THURSDAY/CHRISTMAS DAY AS THE LOW PULLS AWAY TO
THE NORTHEAST.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO





Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1158 AM CST Fri Dec 19 2014

.UPDATE...
ISSUED AT 1035 AM CST FRI DEC 19 2014

16z/10am visible satellite imagery shows sunny skies across most
of central Illinois, with low clouds bracketing the KILX CWA to
the west, north, and east. This large area of clearing developed
directly beneath a ridge of high pressure last night and has
persisted through this morning. Main short-term challenge will be
whether or not skies will become overcast again today. Satellite
loops over the past couple of hours are showing very little
change, with even some erosion of the cloud cover across the far
SW CWA around Jacksonville. With surface high remaining in place
and very weak low-level winds, do not see clouds currently in
place across Iowa/Missouri returning very quickly. NAM forecast
soundings generally remain dry until later in the afternoon when
low clouds slowly begin to encroach from the west and high/thin
cirrus stream northeastward from a storm system tracking across
the southern Plains. End result will be a partly to mostly sunny
day across central Illinois with afternoon high temperatures
reaching the lower to middle 30s.

&&

.SHORT TERM...(Today)
ISSUED AT 459 AM CST FRI DEC 19 2014

High pressure is expected to hold over central Illinois through
today with the next southern stream shortwave, currently over south
central Texas early this morning, forecast to track well south of
our area. 2am satellite data and surface observations showing an
area of clear skies extending from just northwest of Peoria
southeast thru Champaign and Decatur. Short range models suggest
this area will gradually fill back in with clouds as the day wears
on. Forecast soundings from the HRRR and Rapid Refresh models also
support this idea thru the day with the last few satellite frames
off the IR loop indicating the clouds over far west central IL were
starting to shift more to the east. Forecast soundings across
central IL today support afternoon temperatures in the low to mid
30s with another day with very little wind, something that is a bit
on the rare side for December across our area.

&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 459 AM CST FRI DEC 19 2014

Main focus remains with active pattern setting up for the upcoming
holiday week.

Powerful jet of 120-160 knots at 300 mb will be coming into the
Pacific Northwest later this weekend before diving toward the
southern Plains, helping to carve out a deep trough over the central
U.S. The GFS and ECMWF models are in good agreement with development
of a closed low over eastern South Dakota by midday Monday, with
some minor disagreements as to the amount of wobbling of this low as
it drifts toward the east. The ECMWF brings the center as far south
as Springfield by Wednesday morning, while the GFS and Canadian
models are centered across Wisconsin.

Precipitation shield with this system expected to start spreading
into the Illinois River valley by late Monday morning, then eastward
across the state during the day. The GFS is more prominent with a
dry slot punching in already by late evening, while the ECMWF
lingers the rain into Tuesday morning. Leaned more towards the
slower ECMWF solution and increased rain chances to around 60%
Monday night north of I-74 and east of I-57. Forecast soundings are
well above freezing up to around 850 mb, so have removed any mixed
precip wording for Monday night. Some mixture possible northwest of
the Illinois River on Tuesday, although a loss of ice crystals aloft
with the dry slot may mitigate this.

As we head toward Christmas Eve, amount of wrap-around precipitation
is a concern. The ECMWF rapidly intensifies the surface cyclone to
our east, with central pressure down to around 978 mb midday near
Cleveland. This solution brings periodic snow showers southeast into
our area in the strong northwest flow. The much weaker GFS has some
flurries lingering through the day, with less windy conditions. Have
kept precipitation chances across the east during the day on the
edge of the ECMWF`s dry slot, but kept only slight chances elsewhere
for now. Snowfall amounts still appear to be on the light side, but
holiday travel will still not be pleasant with the snow and the
winds. Christmas Day itself appears dry.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1158 AM CST FRI DEC 19 2014

Latest satellite imagery continues to indicate mostly clear skies
across much of central Illinois late this morning, with VFR ceilings
persisting at only KSPI. Further west, MVFR/IFR ceilings blanket
Iowa/Missouri. With high pressure directly overhead, low-level
winds are quite light and will remain light until the high begins
to shift off to the east later tonight into Saturday. At that
time, return flow on the back side of the slowly departing high
will allow lower clouds to spill back into the area from the W/SW.
Have therefore gone with VFR conditions across the board this
afternoon/evening, followed by a gradual return of MVFR ceilings
overnight into Saturday morning. Have lowered ceilings to around
2500ft and introduced restricted visbys down to 4sm between 13z
and 16z accordingly.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Barnes








AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1137 AM CST FRI DEC 19 2014

.SHORT TERM...
259 AM CST

THROUGH SUNDAY...

THE MAIN CONCERNS DURING THE SHORT TERM WILL BE SOME PERIODIC
CHANCES OF VERY LIGHT SNOW OR DRIZZLE THROUGH THE WEEKEND AS SEVERAL
WEAK...AND FAST MOVING MID LEVEL DISTURBANCES SHIFT ACROSS THE AREA.

SURFACE HIGH PRESSURE IS CENTERED ACROSS MUCH OF THE MID AND UPPER
MISSISSIPPI RIVER VALLEY EARLY THIS MORNING. THIS FEATURE IS EXPECTED
TO REMAIN IN CONTROL ACROSS NORTHERN ILLINOIS DURING THE DAY TODAY.
OVERALL...WHICH WILL RESULT IN A VERY LIGHT AND VARIABLE WIND
FIELD ACROSS THE AREA TODAY. AN AREA OF LAKE EFFECT FLURRIES
CONTINUES ACROSS PORTIONS OF THE CHICAGO AREA...AND INTO
NORTHWESTERN INDIANA NEAR LAKE MICHIGAN. MODEL SOUNDINGS INDICATE
JUST DEEP ENOUGH INVERSION HEIGHTS TO SUPPORT ICE IN THE
CLOUDS...AND GIVEN MDW HAS BEEN REPORTING ONLY -SN FOR MOST OF THE
NIGHT IT APPEARS THE THREAT OF FREEZING DRIZZLE WILL BE LOW. ALL
OF THIS ACTIVITY SHOULD WANE ACROSS THE AREA DURING THE MORNING AS
THE WIND FIELD CONTINUES TO WEAKEN OVER SOUTH LAKE MICHIGAN IN
RESPONSE TO THE APPROACHING SURFACE RIDGE OF HIGH PRESSURE.

SURFACE WINDS WILL BEGIN TO SHIFT OUT OF THE SOUTH BY EARLY SATURDAY
MORNING AS THIS SURFACE HIGH BEGINS TO SHIFT EAST OF THE REGION. AS
THIS OCCURS...GUIDANCE IS INSISTENT WITH BRINGING A WEAK UPPER
DISTURBANCE ACROSS NORTHERN ILLINOIS SATURDAY MORNING. THIS WEAK
WAVE IS NOTED IN THE WATER VAPOR IMAGERY CURRENTLY ACROSS
SOUTHEASTERN ALBERTA. MOISTURE APPEARS TO REMAIN LIMITED WITH THIS
WAVE. HOWEVER...I THINK THIS WAVE...AND SOME WEAK ISENTROPIC ASCENT
COULD SQUEEZE OUT A FEW FLURRIES SATURDAY MORNING...SO I HAVE
INCLUDED A SLIGHT CHANCE FOR SUCH IN THE FORECAST.

WARM AIR ADVECTION/ISENTROPIC ASCENT WILL CONTINUE TO INCREASE
ACROSS MUCH OF THE MIDWEST AND GREAT LAKES REGION INTO SUNDAY IN
RESPONSE TO AN INCREASING SOUTHERLY WIND FIELD AHEAD OF A STORM
SYSTEM...WHICH IS EXPECTED TO DEVELOP ACROSS THE PLAINS. THIS COULD
AGAIN RESULT IN A PERIOD OF LIGHT PRECIP ACROSS MAINLY FAR NORTHERN
ILLINOIS VERY LATE SATURDAY NIGHT AND INTO SUNDAY.
OVERALL...CONFIDENCE IS LOW AS TO HOW FAR SOUTH THIS LIGHT PRECIP
WILL BE ABLE TO DEVELOP...BUT GIVEN THE POTENTIAL THAT IF THIS
PRECIP DOES DEVELOP AS FAR SOUTH AS NORTHERN ILLINOIS...THERE COULD
BE A PERIOD OF FREEZING DRIZZLE INTO EARLY SUNDAY MORNING BEFORE
TEMPERATURES JUMP ABOVE FREEZING...I HAVE OPTED TO INCLUDE A SLIGHT
MENTION LATE SATURDAY NIGHT INTO EARLY SUNDAY...MAINLY FOR AREAS
NORTH OF INTERSTATE 90.

KJB

&&

.LONG TERM...
259 AM CST

SUNDAY NIGHT THROUGH THURSDAY...

THE LONG TERM PERIOD WILL BE A PERIOD OF A SIGNIFICANT WEATHER
PATTERN SHIFT ACROSS NORTH AMERICA AND AS SUCH...IT APPEARS LIKELY
THAT THE CENTRAL CONUS WILL BECOME MUCH MORE ACTIVE INTO THE
HOLIDAY WEEK. THE MAIN CONCERNS LOCALLY WITH THIS PATTERN
SHIFT...WILL BE PRECIP TYPES...AND THE ACTUAL EVOLUTION
OF...POTENTIALLY A SIGNIFICANT STORM SYSTEM ACROSS PORTIONS OF THE
GREAT LAKES REGION CHRISTMAS EVE.

UNFORTUNATELY...THE DETAILS OF THIS STORM SYSTEM THIS FAR OUT ARE
STILL LARGELY UNCERTAIN...AS LARGE SCALE PATTERN SHIFTS SUCH AS THIS
TYPICAL RESULT IN LOWER PREDICTABILITY...ESPECIALLY WITH REGARDS TO
THE TRACK AND ACTUAL STRENGTH OF A DEVELOPING STORM SYSTEM. WHAT
APPEARS TO BE LIKELY...HOWEVER...IS FOR A PERIOD OF RAIN ACROSS THE
AREA LATE MONDAY AND MONDAY NIGHT AS WHAT APPEARS TO BE THE INITIAL
STORM SYSTEM...BEGINS TO SHIFT A WARM FRONT ACROSS NORTHERN
ILLINOIS. GIVEN THE WARM SECTOR PLACEMENT OF MY AREA...PRECIP TYPE
LOOKS TO BE LIQUID...WITH SURFACE TEMPERATURES LIKELY TO REMAIN
ABOVE FREEZING MONDAY NIGHT WITH CONTINUED SOUTHERN FLOW.

THE MAIN UNCERTAINTIES COME INTO PLAY BY CHRISTMAS EVE...AS MODEL
GUIDANCE CONTINUES TO ADVERTISE A SIGNIFICANT AMPLIFICATION TO THE
UPPER LEVEL PATTERN ACROSS THE EASTERN PACIFIC AND NORTH AMERICA. A
STRONG PACIFIC JET (NEAR 40 DEGREES N)...INITIALIZED AT OVER 180 KT
IN THIS EVENINGS MODEL OUTPUT IS FORECAST TO RESULT IN THE BUILDING
OF A POTENT UPPER RIDGE JUST OFF THE CALIFORNIA COAST BY EARLY NEXT
WEEK. TELECONNECTIONS RELATED TO SUCH PATTERN SHIFT CERTAINLY SUPPORT
THE DIGGING OF A SIGNIFICANT TROUGH...AND A GOOD POSSIBILITY OF AN
STORM SYSTEM ACROSS THE CENTRAL CONUS DURING THE UPCOMING HOLIDAY
WEEK. HOWEVER...AS PREVIOUSLY MENTIONED CONFIDENCE IS LOW WITH THE
DETAILS OF HOW AND WHERE EXACTLY THIS STORM MAY TRACK. THIS IS A
PERIOD WORTH WATCHING THOUGH...AS AT LEAST SOME SNOW AND POSSIBLY
STRONG NORTHWEST WINDS COULD BE IN STORE.

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* MVFR CIGS.

BMD

//DISCUSSION...UPDATED 18Z...

RELATIVELY UNCHANGING CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
THE TAF PERIOD WITH PRIMARILY MVFR CIGS AND LIGHT WINDS. WINDS THIS
AFTERNOON ARE GENERALLY 5 KT OR LESS AND OUT OF THE NORTH OR
NORTHWEST...BUT WILL LIKELY BECOME MORE VARIABLE AND POSSIBLY CALM
FOR A PERIOD THIS EVENING AND OVERNIGHT...BEFORE SOUTHERLY WINDS
START TO CREEP IN BEHIND THE HIGH TOMORROW. WHILE A FEW BREAKS IN
THE CLOUDS MAY DEVELOP...EXPECT MVFR CIGS TO GENERALLY REMAIN LOCKED
IN UNDER A STRONG INVERSION WITH SOME LOWERING OVERNIGHT.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM IN CIGS.
* HIGH IN REMAINING FORECAST ELEMENTS.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...

SATURDAY NIGHT...MVFR LIKELY. LIGHT SOUTH WINDS.

SUNDAY...SLGT CHANCE FLURRIES/FREEZING DRIZZLE EARLY. MVFR LIKELY.
SOUTH-SOUTHEAST WINDS.

MONDAY AND TUESDAY...CHANCE OF RAIN...ESPECIALLY MONDAY NIGHT. MVFR
LIKELY. SOUTHEAST WINDS MONDAY BECOMING SOUTHWEST TUESDAY.

WEDNESDAY...CHANCE OF SNOW. MVFR POSSIBLE. GUSTY WEST WINDS.

THURSDAY...DRY. VFR.

RATZER

&&

.MARINE...
156 AM CST

MAIN MARINE CONCERNS THIS MORNING ARE A PERIOD OF STRENGTHENING
SOUTH-SOUTHEAST WINDS LATE SUNDAY THROUGH MONDAY NIGHT...THEN THE
POTENTIAL FOR WEST GALES LATE WEDNESDAY INTO THURSDAY.

FAIRLY QUIET STRETCH OF WEATHER ACROSS LAKE MICHIGAN TODAY THROUGH
SATURDAY AS A LARGE AREA OF WEAK HIGH PRESSURE DRIFTS SLOWLY EAST
ACROSS THE REGION. LIGHT NORTH WINDS TODAY WILL BECOME SOMEWHAT
LIGHT/VARIABLE...BEFORE BECOMING LIGHT SOUTH ON SATURDAY AS THE
SURFACE RIDGE AXIS PASSES TO THE EAST. SOUTHERLY WINDS WILL THEN
BEGIN TO INCREASE SATURDAY NIGHT AND MORE SO SUNDAY...AS LOW
PRESSURE DEVELOPS IN THE LEE OF THE NORTHERN ROCKIES AND THE
GRADIENT BEGINS TO TIGHTEN ACROSS THE PLAINS AND UPPER MIDWEST.
MEDIUM RANGE FORECAST MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING
A SUB-1000 MB SURFACE LOW ACROSS IOWA OR SOUTHERN MINNESOTA BY
MIDDAY MONDAY...WHICH WOULD LEAD TO SOUTH-SOUTHEAST WINDS IN THE
20-25 KT RANGE THROUGH MONDAY BEFORE OCCLUDING AND WEAKENING AS THE
LOW MOVES ACROSS WISCONSIN AND LAKE MICHIGAN ON TUESDAY.

HOWEVER...VARIOUS MODEL AND MODEL ENSEMBLE MEMBERS THEN DEVELOP A
SECOND LOW SOUTH OF THE LAKES ALONG THE TRAILING COLD FRONT TUESDAY
NIGHT...WHICH WOULD LIFT NORTH AND COMBINE WITH THE FILLING GREAT
LAKES LOW...DEEPENING RAPIDLY WEDNESDAY AND WEDNESDAY NIGHT OVER THE
EASTERN LAKES. THIS SCENARIO WOULD LEAD TO QUICKLY INCREASING
WESTERLY WINDS ACROSS LAKE MICHIGAN...QUITE POSSIBLY WEST GALES...
LATE WEDNESDAY INTO THURSDAY/CHRISTMAS DAY AS THE LOW PULLS AWAY TO
THE NORTHEAST.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1035 AM CST Fri Dec 19 2014

.UPDATE...
ISSUED AT 1035 AM CST FRI DEC 19 2014

16z/10am visible satellite imagery shows sunny skies across most
of central Illinois, with low clouds bracketing the KILX CWA to
the west, north, and east. This large area of clearing developed
directly beneath a ridge of high pressure last night and has
persisted through this morning. Main short-term challenge will be
whether or not skies will become overcast again today. Satellite
loops over the past couple of hours are showing very little
change, with even some erosion of the cloud cover across the far
SW CWA around Jacksonville. With surface high remaining in place
and very weak low-level winds, do not see clouds currently in
place across Iowa/Missouri returning very quickly. NAM forecast
soundings generally remain dry until later in the afternoon when
low clouds slowly begin to encroach from the west and high/thin
cirrus stream northeastward from a storm system tracking across
the southern Plains. End result will be a partly to mostly sunny
day across central Illinois with afternoon high temperatures
reaching the lower to middle 30s.

&&

.SHORT TERM...(Today)
ISSUED AT 459 AM CST FRI DEC 19 2014

High pressure is expected to hold over central Illinois through
today with the next southern stream shortwave, currently over south
central Texas early this morning, forecast to track well south of
our area. 2am satellite data and surface observations showing an
area of clear skies extending from just northwest of Peoria
southeast thru Champaign and Decatur. Short range models suggest
this area will gradually fill back in with clouds as the day wears
on. Forecast soundings from the HRRR and Rapid Refresh models also
support this idea thru the day with the last few satellite frames
off the IR loop indicating the clouds over far west central IL were
starting to shift more to the east. Forecast soundings across
central IL today support afternoon temperatures in the low to mid
30s with another day with very little wind, something that is a bit
on the rare side for December across our area.

&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 459 AM CST FRI DEC 19 2014

Main focus remains with active pattern setting up for the upcoming
holiday week.

Powerful jet of 120-160 knots at 300 mb will be coming into the
Pacific Northwest later this weekend before diving toward the
southern Plains, helping to carve out a deep trough over the central
U.S. The GFS and ECMWF models are in good agreement with development
of a closed low over eastern South Dakota by midday Monday, with
some minor disagreements as to the amount of wobbling of this low as
it drifts toward the east. The ECMWF brings the center as far south
as Springfield by Wednesday morning, while the GFS and Canadian
models are centered across Wisconsin.

Precipitation shield with this system expected to start spreading
into the Illinois River valley by late Monday morning, then eastward
across the state during the day. The GFS is more prominent with a
dry slot punching in already by late evening, while the ECMWF
lingers the rain into Tuesday morning. Leaned more towards the
slower ECMWF solution and increased rain chances to around 60%
Monday night north of I-74 and east of I-57. Forecast soundings are
well above freezing up to around 850 mb, so have removed any mixed
precip wording for Monday night. Some mixture possible northwest of
the Illinois River on Tuesday, although a loss of ice crystals aloft
with the dry slot may mitigate this.

As we head toward Christmas Eve, amount of wrap-around precipitation
is a concern. The ECMWF rapidly intensifies the surface cyclone to
our east, with central pressure down to around 978 mb midday near
Cleveland. This solution brings periodic snow showers southeast into
our area in the strong northwest flow. The much weaker GFS has some
flurries lingering through the day, with less windy conditions. Have
kept precipitation chances across the east during the day on the
edge of the ECMWF`s dry slot, but kept only slight chances elsewhere
for now. Snowfall amounts still appear to be on the light side, but
holiday travel will still not be pleasant with the snow and the
winds. Christmas Day itself appears dry.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 525 AM CST FRI DEC 19 2014

High pressure centered from northeast Iowa southeast thru central
Illinois has helped to scour out some of the MVFR clouds that
have dominated our area over the past 24 hours, especially along
the ridge axis early this morning. Satellite data indicates the
clear area extended from Moline southeast thru Peoria, Bloomington
and Champaign with MVFR cigs to the north and south. Forecast
soundings continue to suggest areas that were experiencing the
clear skies this morning should see the low VFR and even some MVFR
cigs move back in by later this morning into the afternoon hours.
Confidence on timing and extent of the lower VFR and MVFR cigs
across the area today is rather low, so will trend with more
clouds across the north and east by later this morning into the
afternoon hours but keep it mostly low VFR at this time. Surface
winds will once again be a non- factor today as our area will be
under the high pressure system so will continue with a light and
variable wind over most of the area into tonight.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith







AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 552 AM CST FRI DEC 19 2014

.SHORT TERM...
259 AM CST

THROUGH SUNDAY...

THE MAIN CONCERNS DURING THE SHORT TERM WILL BE SOME PERIODIC
CHANCES OF VERY LIGHT SNOW OR DRIZZLE THROUGH THE WEEKEND AS SEVERAL
WEAK...AND FAST MOVING MID LEVEL DISTURBANCES SHIFT ACROSS THE AREA.

SURFACE HIGH PRESSURE IS CENTERED ACROSS MUCH OF THE MID AND UPPER
MISSISSIPPI RIVER VALLEY EARLY THIS MORNING. THIS FEATURE IS EXPECTED
TO REMAIN IN CONTROL ACROSS NORTHERN ILLINOIS DURING THE DAY TODAY.
OVERALL...WHICH WILL RESULT IN A VERY LIGHT AND VARIABLE WIND
FIELD ACROSS THE AREA TODAY. AN AREA OF LAKE EFFECT FLURRIES
CONTINUES ACROSS PORTIONS OF THE CHICAGO AREA...AND INTO
NORTHWESTERN INDIANA NEAR LAKE MICHIGAN. MODEL SOUNDINGS INDICATE
JUST DEEP ENOUGH INVERSION HEIGHTS TO SUPPORT ICE IN THE
CLOUDS...AND GIVEN MDW HAS BEEN REPORTING ONLY -SN FOR MOST OF THE
NIGHT IT APPEARS THE THREAT OF FREEZING DRIZZLE WILL BE LOW. ALL
OF THIS ACTIVITY SHOULD WANE ACROSS THE AREA DURING THE MORNING AS
THE WIND FIELD CONTINUES TO WEAKEN OVER SOUTH LAKE MICHIGAN IN
RESPONSE TO THE APPROACHING SURFACE RIDGE OF HIGH PRESSURE.

SURFACE WINDS WILL BEGIN TO SHIFT OUT OF THE SOUTH BY EARLY SATURDAY
MORNING AS THIS SURFACE HIGH BEGINS TO SHIFT EAST OF THE REGION. AS
THIS OCCURS...GUIDANCE IS INSISTENT WITH BRINGING A WEAK UPPER
DISTURBANCE ACROSS NORTHERN ILLINOIS SATURDAY MORNING. THIS WEAK
WAVE IS NOTED IN THE WATER VAPOR IMAGERY CURRENTLY ACROSS
SOUTHEASTERN ALBERTA. MOISTURE APPEARS TO REMAIN LIMITED WITH THIS
WAVE. HOWEVER...I THINK THIS WAVE...AND SOME WEAK ISENTROPIC ASCENT
COULD SQUEEZE OUT A FEW FLURRIES SATURDAY MORNING...SO I HAVE
INCLUDED A SLIGHT CHANCE FOR SUCH IN THE FORECAST.

WARM AIR ADVECTION/ISENTROPIC ASCENT WILL CONTINUE TO INCREASE
ACROSS MUCH OF THE MIDWEST AND GREAT LAKES REGION INTO SUNDAY IN
RESPONSE TO AN INCREASING SOUTHERLY WIND FIELD AHEAD OF A STORM
SYSTEM...WHICH IS EXPECTED TO DEVELOP ACROSS THE PLAINS. THIS COULD
AGAIN RESULT IN A PERIOD OF LIGHT PRECIP ACROSS MAINLY FAR NORTHERN
ILLINOIS VERY LATE SATURDAY NIGHT AND INTO SUNDAY.
OVERALL...CONFIDENCE IS LOW AS TO HOW FAR SOUTH THIS LIGHT PRECIP
WILL BE ABLE TO DEVELOP...BUT GIVEN THE POTENTIAL THAT IF THIS
PRECIP DOES DEVELOP AS FAR SOUTH AS NORTHERN ILLINOIS...THERE COULD
BE A PERIOD OF FREEZING DRIZZLE INTO EARLY SUNDAY MORNING BEFORE
TEMPERATURES JUMP ABOVE FREEZING...I HAVE OPTED TO INCLUDE A SLIGHT
MENTION LATE SATURDAY NIGHT INTO EARLY SUNDAY...MAINLY FOR AREAS
NORTH OF INTERSTATE 90.

KJB

&&

.LONG TERM...
259 AM CST

SUNDAY NIGHT THROUGH THURSDAY...

THE LONG TERM PERIOD WILL BE A PERIOD OF A SIGNIFICANT WEATHER
PATTERN SHIFT ACROSS NORTH AMERICA AND AS SUCH...IT APPEARS LIKELY
THAT THE CENTRAL CONUS WILL BECOME MUCH MORE ACTIVE INTO THE
HOLIDAY WEEK. THE MAIN CONCERNS LOCALLY WITH THIS PATTERN
SHIFT...WILL BE PRECIP TYPES...AND THE ACTUAL EVOLUTION
OF...POTENTIALLY A SIGNIFICANT STORM SYSTEM ACROSS PORTIONS OF THE
GREAT LAKES REGION CHRISTMAS EVE.

UNFORTUNATELY...THE DETAILS OF THIS STORM SYSTEM THIS FAR OUT ARE
STILL LARGELY UNCERTAIN...AS LARGE SCALE PATTERN SHIFTS SUCH AS THIS
TYPICAL RESULT IN LOWER PREDICTABILITY...ESPECIALLY WITH REGARDS TO
THE TRACK AND ACTUAL STRENGTH OF A DEVELOPING STORM SYSTEM. WHAT
APPEARS TO BE LIKELY...HOWEVER...IS FOR A PERIOD OF RAIN ACROSS THE
AREA LATE MONDAY AND MONDAY NIGHT AS WHAT APPEARS TO BE THE INITIAL
STORM SYSTEM...BEGINS TO SHIFT A WARM FRONT ACROSS NORTHERN
ILLINOIS. GIVEN THE WARM SECTOR PLACEMENT OF MY AREA...PRECIP TYPE
LOOKS TO BE LIQUID...WITH SURFACE TEMPERATURES LIKELY TO REMAIN
ABOVE FREEZING MONDAY NIGHT WITH CONTINUED SOUTHERN FLOW.

THE MAIN UNCERTAINTIES COME INTO PLAY BY CHRISTMAS EVE...AS MODEL
GUIDANCE CONTINUES TO ADVERTISE A SIGNIFICANT AMPLIFICATION TO THE
UPPER LEVEL PATTERN ACROSS THE EASTERN PACIFIC AND NORTH AMERICA. A
STRONG PACIFIC JET (NEAR 40 DEGREES N)...INITIALIZED AT OVER 180 KT
IN THIS EVENINGS MODEL OUTPUT IS FORECAST TO RESULT IN THE BUILDING
OF A POTENT UPPER RIDGE JUST OFF THE CALIFORNIA COAST BY EARLY NEXT
WEEK. TELECONNECTIONS RELATED TO SUCH PATTERN SHIFT CERTAINLY SUPPORT
THE DIGGING OF A SIGNIFICANT TROUGH...AND A GOOD POSSIBILITY OF AN
STORM SYSTEM ACROSS THE CENTRAL CONUS DURING THE UPCOMING HOLIDAY
WEEK. HOWEVER...AS PREVIOUSLY MENTIONED CONFIDENCE IS LOW WITH THE
DETAILS OF HOW AND WHERE EXACTLY THIS STORM MAY TRACK. THIS IS A
PERIOD WORTH WATCHING THOUGH...AS AT LEAST SOME SNOW AND POSSIBLY
STRONG NORTHWEST WINDS COULD BE IN STORE.

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* A FEW LINGERING FLURRIES EARLY THIS AM...MAINLY MDW AND
  SOUTHEAST.

* MVFR CEILINGS TO PERSIST MUCH OF PERIOD...LIFTING NEAR VFR OR
  POSSIBLY SCATTERING OUT FOR A TIME MID-MORNING THROUGH THIS
  AFTERNOON.

* LIGHT WINDS 5 KT OR LESS. STARTING WEST-NORTHWEST EARLY THIS
  MORNING...LIKELY VARIABLE OR CALM LATER TODAY/THIS EVENING.

RATZER

//DISCUSSION...UPDATED 12Z...

DIFFUSE SURFACE HIGH PRESSURE RIDGE OVER THE AREA WILL DRIFT VERY
SLOWLY TO THE EAST TODAY AND TONIGHT...RESULTING IN LIGHT WINDS
AND PERSISTENT MVFR CLOUD LAYER TRAPPED BENEATH SHALLOW INVERSION.
AREA OF CLEARING SOUTH OF THE TERMINALS FROM MLI-DNV-IND NOT
MOVING MUCH...THOUGH THERE HAS BEEN SOME EROSION OF CEILINGS
SOUTHWEST OF CHICAGO. FORECAST SOUNDINGS GENERALLY POOR AT
HANDLING MOISTURE BENEATH THIS SHALLOW INVERSION...BUT THERE IS
SOME INDICATION OF SOME RAISING OF CEILINGS OR EVEN SCATTERING
OUT FOR A TIME LATER THIS MORNING INTO THIS AFTERNOON. MVFR
CEILINGS LIKELY TO REDEVELOP AND/OR LOWER LATER TONIGHT HOWEVER AS
SURFACE RIDGE PASSES AND LIGHT SOUTH-SOUTHWEST FLOW DEVELOPS AND
LEADS TO MOISTENING OF LOW LEVELS.

AS FOR WINDS...LIGHT NORTHERLY SFC FLOW AROUND 5 KT EXPECTED TO
BECOME VARIABLE AT LESS THAN 5 KT AS SURFACE RIDGE MOVES THROUGH
TODAY AND THIS EVENING. WINDS THEN BECOME SOUTH-SOUTHWEST AROUND 5
KT TONIGHT INTO SATURDAY MORNING.

RATZER


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* MEDIUM-LOW IN CEILING HEIGHTS...THOUGH MEDIUM IN GENERAL TREND.

* HIGH IN LIGHT WIND TRENDS.

RATZER

//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...

SATURDAY NIGHT...MVFR LIKELY. LIGHT SOUTH WINDS.

SUNDAY...SLGT CHANCE FLURRIES/FREEZING DRIZZLE EARLY. MVFR LIKELY.
SOUTH-SOUTHEAST WINDS.

MONDAY AND TUESDAY...CHANCE OF RAIN...ESPECIALLY MONDAY NIGHT. MVFR
LIKELY. SOUTHEAST WINDS MONDAY BECOMING SOUTHWEST TUESDAY.

WEDNESDAY...CHANCE OF SNOW. MVFR POSSIBLE. GUSTY WEST WINDS.

THURSDAY...DRY. VFR.

RATZER

&&

.MARINE...
156 AM CST

MAIN MARINE CONCERNS THIS MORNING ARE A PERIOD OF STRENGTHENING
SOUTH-SOUTHEAST WINDS LATE SUNDAY THROUGH MONDAY NIGHT...THEN THE
POTENTIAL FOR WEST GALES LATE WEDNESDAY INTO THURSDAY.

FAIRLY QUIET STRETCH OF WEATHER ACROSS LAKE MICHIGAN TODAY THROUGH
SATURDAY AS A LARGE AREA OF WEAK HIGH PRESSURE DRIFTS SLOWLY EAST
ACROSS THE REGION. LIGHT NORTH WINDS TODAY WILL BECOME SOMEWHAT
LIGHT/VARIABLE...BEFORE BECOMING LIGHT SOUTH ON SATURDAY AS THE
SURFACE RIDGE AXIS PASSES TO THE EAST. SOUTHERLY WINDS WILL THEN
BEGIN TO INCREASE SATURDAY NIGHT AND MORE SO SUNDAY...AS LOW
PRESSURE DEVELOPS IN THE LEE OF THE NORTHERN ROCKIES AND THE
GRADIENT BEGINS TO TIGHTEN ACROSS THE PLAINS AND UPPER MIDWEST.
MEDIUM RANGE FORECAST MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING
A SUB-1000 MB SURFACE LOW ACROSS IOWA OR SOUTHERN MINNESOTA BY
MIDDAY MONDAY...WHICH WOULD LEAD TO SOUTH-SOUTHEAST WINDS IN THE
20-25 KT RANGE THROUGH MONDAY BEFORE OCCLUDING AND WEAKENING AS THE
LOW MOVES ACROSS WISCONSIN AND LAKE MICHIGAN ON TUESDAY.

HOWEVER...VARIOUS MODEL AND MODEL ENSEMBLE MEMBERS THEN DEVELOP A
SECOND LOW SOUTH OF THE LAKES ALONG THE TRAILING COLD FRONT TUESDAY
NIGHT...WHICH WOULD LIFT NORTH AND COMBINE WITH THE FILLING GREAT
LAKES LOW...DEEPENING RAPIDLY WEDNESDAY AND WEDNESDAY NIGHT OVER THE
EASTERN LAKES. THIS SCENARIO WOULD LEAD TO QUICKLY INCREASING
WESTERLY WINDS ACROSS LAKE MICHIGAN...QUITE POSSIBLY WEST GALES...
LATE WEDNESDAY INTO THURSDAY/CHRISTMAS DAY AS THE LOW PULLS AWAY TO
THE NORTHEAST.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
537 AM CST Fri Dec 19 2014

.SHORT TERM...(Today)
ISSUED AT 459 AM CST FRI DEC 19 2014

High pressure is expected to hold over central Illinois through
today with the next southern stream shortwave, currently over south
central Texas early this morning, forecast to track well south of
our area. 2am satellite data and surface observations showing an
area of clear skies extending from just northwest of Peoria
southeast thru Champaign and Decatur. Short range models suggest
this area will gradually fill back in with clouds as the day wears
on. Forecast soundings from the HRRR and Rapid Refresh models also
support this idea thru the day with the last few satellite frames
off the IR loop indicating the clouds over far west central IL were
starting to shift more to the east. Forecast soundings across
central IL today support afternoon temperatures in the low to mid
30s with another day with very little wind, something that is a bit
on the rare side for December across our area.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 459 AM CST FRI DEC 19 2014

Main focus remains with active pattern setting up for the upcoming
holiday week.

Powerful jet of 120-160 knots at 300 mb will be coming into the
Pacific Northwest later this weekend before diving toward the
southern Plains, helping to carve out a deep trough over the central
U.S. The GFS and ECMWF models are in good agreement with development
of a closed low over eastern South Dakota by midday Monday, with
some minor disagreements as to the amount of wobbling of this low as
it drifts toward the east. The ECMWF brings the center as far south
as Springfield by Wednesday morning, while the GFS and Canadian
models are centered across Wisconsin.

Precipitation shield with this system expected to start spreading
into the Illinois River valley by late Monday morning, then eastward
across the state during the day. The GFS is more prominent with a
dry slot punching in already by late evening, while the ECMWF
lingers the rain into Tuesday morning. Leaned more towards the
slower ECMWF solution and increased rain chances to around 60%
Monday night north of I-74 and east of I-57. Forecast soundings are
well above freezing up to around 850 mb, so have removed any mixed
precip wording for Monday night. Some mixture possible northwest of
the Illinois River on Tuesday, although a loss of ice crystals aloft
with the dry slot may mitigate this.

As we head toward Christmas Eve, amount of wrap-around precipitation
is a concern. The ECMWF rapidly intensifies the surface cyclone to
our east, with central pressure down to around 978 mb midday near
Cleveland. This solution brings periodic snow showers southeast into
our area in the strong northwest flow. The much weaker GFS has some
flurries lingering through the day, with less windy conditions. Have
kept precipitation chances across the east during the day on the
edge of the ECMWF`s dry slot, but kept only slight chances elsewhere
for now. Snowfall amounts still appear to be on the light side, but
holiday travel will still not be pleasant with the snow and the
winds. Christmas Day itself appears dry.


&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 525 AM CST FRI DEC 19 2014

High pressure centered from northeast Iowa southeast thru central
Illinois has helped to scour out some of the MVFR clouds that
have dominated our area over the past 24 hours, especially along
the ridge axis early this morning. Satellite data indicates the
clear area extended from Moline southeast thru Peoria, Bloomington
and Champaign with MVFR cigs to the north and south. Forecast
soundings continue to suggest areas that were experiencing the
clear skies this morning should see the low VFR and even some MVFR
cigs move back in by later this morning into the afternoon hours.
Confidence on timing and extent of the lower VFR and MVFR cigs
across the area today is rather low, so will trend with more
clouds across the north and east by later this morning into the
afternoon hours but keep it mostly low VFR at this time. Surface
winds will once again be a non- factor today as our area will be
under the high pressure system so will continue with a light and
variable wind over most of the area into tonight.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith





AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 301 AM CST FRI DEC 19 2014

.SHORT TERM...
259 AM CST

THROUGH SUNDAY...

THE MAIN CONCERNS DURING THE SHORT TERM WILL BE SOME PERIODIC
CHANCES OF VERY LIGHT SNOW OR DRIZZLE THROUGH THE WEEKEND AS SEVERAL
WEAK...AND FAST MOVING MID LEVEL DISTURBANCES SHIFT ACROSS THE AREA.

SURFACE HIGH PRESSURE IS CENTERED ACROSS MUCH OF THE MID AND UPPER
MISSISSIPPI RIVER VALLEY EARLY THIS MORNING. THIS FEATURE IS EXPECTED
TO REMAIN IN CONTROL ACROSS NORTHERN ILLINOIS DURING THE DAY TODAY.
OVERALL...WITH WILL RESULT IN A VERY LIGHT AND VARIABLE WIND FIELD
ACROSS THE AREA TODAY. AN AREA OF LAKE EFFECT FLURRIES CONTINUES
ACROSS PORTIONS OF THE CHICAGO AREA...AND INTO NORTHWESTERN INDIANA
NEAR LAKE MICHIGAN. MODEL SOUNDINGS INDICATE JUST DEEP ENOUGH
INVERSION HEIGHTS TO SUPPORT ICE IN THE CLOUDS...AND GIVEN MDW HAS
BEEN REPORTING ONLY -SN FOR MOST OF THE NIGHT IT APPEARS THE THREAT
OF FREEZING DRIZZLE WILL BE LOW. ALL OF THIS ACTIVITY SHOULD WANE
ACROSS THE AREA DURING THE MORNING AS THE WIND FIELD CONTINUES TO
WEAKEN OVER SOUTH LAKE MICHIGAN IN RESPONSE TO THE APPROACHING
SURFACE RIDGE OF HIGH PRESSURE.

SURFACE WINDS WILL BEGIN TO SHIFT OUT OF THE SOUTH BY EARLY SATURDAY
MORNING AS THIS SURFACE HIGH BEGINS TO SHIFT EAST OF THE REGION. AS
THIS OCCURS...GUIDANCE IS INSISTENT WITH BRINGING A WEAK UPPER
DISTURBANCE ACROSS NORTHERN ILLINOIS SATURDAY MORNING. THIS WEAK
WAVE IS NOTED IN THE WATER VAPOR IMAGERY CURRENTLY ACROSS
SOUTHEASTERN ALBERTA. MOISTURE APPEARS TO REMAIN LIMITED WITH THIS
WAVE. HOWEVER...I THINK THIS WAVE...AND SOME WEAK ISENTROPIC ASCENT
COULD SQUEEZE OUT A FEW FLURRIES SATURDAY MORNING...SO I HAVE
INCLUDED A SLIGHT CHANCE FOR SUCH IN THE FORECAST.

WARM AIR ADVECTION/ISENTROPIC ASCENT WILL CONTINUE TO INCREASE
ACROSS MUCH OF THE MIDWEST AND GREAT LAKES REGION INTO SUNDAY IN
RESPONSE TO AN INCREASING SOUTHERLY WIND FIELD AHEAD OF A STORM
SYSTEM...WHICH IS EXPECTED TO DEVELOP ACROSS THE PLAINS. THIS COULD
AGAIN RESULT IN A PERIOD OF LIGHT PRECIP ACROSS MAINLY FAR NORTHERN
ILLINOIS VERY LATE SATURDAY NIGHT AND INTO SUNDAY.
OVERALL...CONFIDENCE IS LOW AS TO HOW FAR SOUTH THIS LIGHT PRECIP
WILL BE ABLE TO DEVELOP...BUT GIVEN THE POTENTIAL THAT IF THIS
PRECIP DOES DEVELOP AS FAR SOUTH AS NORTHERN ILLINOIS...THERE COULD
BE A PERIOD OF FREEZING DRIZZLE INTO EARLY SUNDAY MORNING BEFORE
TEMPERATURES JUMP ABOVE FREEZING...I HAVE OPTED TO INCLUDE A SLIGHT
MENTION LATE SATURDAY NIGHT INTO EARLY SUNDAY...MAINLY FOR AREAS
NORTH OF INTERSTATE 90.

KJB

&&

.LONG TERM...
259 AM CST

SUNDAY NIGHT THROUGH THURSDAY...

THE LONG TERM PERIOD WILL BE A PERIOD OF A SIGNIFICANT WEATHER
PATTERN SHIFT ACROSS NORTH AMERICA AND AS SUCH...IT APPEARS LIKELY
THAT THE CENTRAL CONUS WILL BECOME MUCH MORE ACTIVE INTO THE
HOLIDAY WEEK. THE MAIN CONCERNS LOCALLY WITH THIS PATTERN
SHIFT...WILL BE PRECIP TYPES...AND THE ACTUAL EVOLUTION
OF...POTENTIALLY A SIGNIFICANT STORM SYSTEM ACROSS PORTIONS OF THE
GREAT LAKES REGION CHRISTMAS EVE.

UNFORTUNATELY...THE DETAILS OF THIS STORM SYSTEM THIS FAR OUT ARE
STILL LARGELY UNCERTAIN...AS LARGE SCALE PATTERN SHIFTS SUCH AS THIS
TYPICAL RESULT IN LOWER PREDICTABILITY...ESPECIALLY WITH REGARDS TO
THE TRACK AND ACTUAL STRENGTH OF A DEVELOPING STORM SYSTEM. WHAT
APPEARS TO BE LIKELY...HOWEVER...IS FOR A PERIOD OF RAIN ACROSS THE
AREA LATE MONDAY AND MONDAY NIGHT AS WHAT APPEARS TO BE THE INITIAL
STORM SYSTEM...BEGINS TO SHIFT A WARM FRONT ACROSS NORTHERN
ILLINOIS. GIVEN THE WARM SECTOR PLACEMENT OF MY AREA...PRECIP TYPE
LOOKS TO BE LIQUID...WITH SURFACE TEMPERATURES LIKELY TO REMAIN
ABOVE FREEZING MONDAY NIGHT WITH CONTINUED SOUTHERN FLOW.

THE MAIN UNCERTAINTIES COME INTO PLAY BY CHRISTMAS EVE...AS MODEL
GUIDANCE CONTINUES TO ADVERTISE A SIGNIFICANT AMPLIFICATION TO THE
UPPER LEVEL PATTERN ACROSS THE EASTERN PACIFIC AND NORTH AMERICA. A
STRONG PACIFIC JET (NEAR 40 DEGREES N)...INITIALIZED AT OVER 180 KT
IN THIS EVENINGS MODEL OUTPUT IS FORECAST TO RESULT IN THE BUILDING
OF A POTENT UPPER RIDGE JUST OFF THE CALIFORNIA COAST BY EARLY NEXT
WEEK. TELECONNECTIONS RELATED TO SUCH PATTERN SHIFT CERTAINLY SUPPORT
THE DIGGING OF A SIGNIFICANT TROUGH...AND A GOOD POSSIBILITY OF AN
STORM SYSTEM ACROSS THE CENTRAL CONUS DURING THE UPCOMING HOLIDAY
WEEK. HOWEVER...AS PREVIOUSLY MENTIONED CONFIDENCE IS LOW WITH THE
DETAILS OF HOW AND WHERE EXACTLY THIS STORM MAY TRACK. THIS IS A
PERIOD WORTH WATCHING THOUGH...AS AT LEAST SOME SNOW AND POSSIBLY
STRONG NORTHWEST WINDS COULD BE IN STORE.

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* BRIEF PERIOD OF FLURRIES/VERY LIGHT SNOW PRE-DAWN. MDW MAY SEE
  VIS REDUCED BRIEFLY TO MVFR.

* MVFR CEILINGS TO PERSIST MUCH OF PERIOD...LIFTING NEAR VFR OR
  POSSIBLY SCATTERING OUT FOR A TIME MID-MORNING THROUGH THIS
  AFTERNOON.

* LIGHT WINDS 5 KT OR LESS. STARTING WEST-NORTHWEST EARLY THIS
  MORNING...LIKELY VARIABLE OR CALM LATER TODAY/THIS EVENING.

RATZER

//DISCUSSION...UPDATED 06Z...

KLOT/TORD AND TMDW RADARS INDICATING SOME WEAK RETURNS OVER
SOUTHERN LAKE MICHIGAN AND THE IMMEDIATE METRO AREAS AT 0530Z.
THESE RETURNS ASSOCIATED WITH LIGHT LAKE-EFFECT PRECIP IN THE
FORM OF LIGHT SNOW...OR FREEZING DRIZZLE. WEB-CAMS FROM DOWNTOWN
INDICATE SOME DROP IN VISIBILITY WITH PRECIP...WHICH RADAR
INDICATES WILL LIKELY AFFECT METRO TERMINALS FOR A TIME EARLY THIS
MORNING. MID-LEVEL DISTURBANCE PASSING 12-15Z SHOULD ALLOW
INVERSION HEIGHTS OVER THE LAKE TO LOWER...WHICH ALONG WITH
WEAKENING LOW LEVEL WIND FIELD SHOULD END PRECIP.

OTHERWISE...EXTENSIVE AREA OF MVFR CIGS REMAINS TRAPPED BENEATH
SHALLOW INVERSION ASSOCIATED WITH WEAK SURFACE HIGH PRESSURE
ACROSS THE REGION...THOUGH SATELLITE IMAGERY DOES SHOW SOME
EROSION/CLEARING OVER PARTS OF EAST CENTRAL AND NORTHEAST WI AS
WELL AS A CORRIDOR ALONG A MLI-PNT-DNV-LAF LINE. SOME INDICATIONS
EXIST THAT THIS CLEARING OVER PARTS OF WI WILL CONTINUE TO WORK
SOUTH-SOUTHWEST ALONG THE WESTERN SHORE OF LAKE MICHIGAN LATER
THIS MORNING AND COULD SCATTER OUT MVFR CLOUDS FOR A TIME LATE
THIS MORNING INTO THIS AFTERNOON. MODEL GUIDANCE IS A LITTLE MORE
PESSIMISTIC BUT DOES ALSO HINT AT RAISING CEILINGS OR SCATTERING
LOW CLOUDS AS WELL.

LIGHT NORTHWEST OR WEST-NORTHWEST WINDS 5 KT OR LESS THIS MORNING
SHOULD BECOME VARIABLE OR CALM LATER TODAY INTO THIS EVENING AS
THE CENTER OF THE WEAK AND DIFFUSE SURFACE HIGH DRIFTS EAST ACROSS
THE TERMINALS. WEAK SOUTH-SOUTHWEST FLOW DEVELOPS JUST ABOVE THE
SURFACE THIS EVENING...FROM WHICH GUIDANCE SUPPORTS A REDEVELOPMENT
OF MVFR CIGS WITH SLOW LOW-LEVEL MOISTENING.

RATZER

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* MEDIUM-HIGH IN CEILING TRENDS...AND BRIEF LIGHT SNOW EARLY THIS
  AM.

* HIGH IN WINDS.

RATZER

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

* SATURDAY AND SUNDAY...DRY/VFR. LIGHT SOUTH WINDS.
* MONDAY...CHANCE OF RAIN/SNOW. MVFR LIKELY. GUSTY SOUTHERLY WINDS.
* TUESDAY...CHANCE OF RAIN/SNOW. IFR LIKELY. SOUTHWEST WINDS.
* WEDNESDAY...CHANCE OF SNOW. MVFR LIKELY. STRONG/GUST WEST WINDS.

BEACHLER

&&

.MARINE...
156 AM CST

MAIN MARINE CONCERNS THIS MORNING ARE A PERIOD OF STRENGTHENING
SOUTH-SOUTHEAST WINDS LATE SUNDAY THROUGH MONDAY NIGHT...THEN THE
POTENTIAL FOR WEST GALES LATE WEDNESDAY INTO THURSDAY.

FAIRLY QUIET STRETCH OF WEATHER ACROSS LAKE MICHIGAN TODAY THROUGH
SATURDAY AS A LARGE AREA OF WEAK HIGH PRESSURE DRIFTS SLOWLY EAST
ACROSS THE REGION. LIGHT NORTH WINDS TODAY WILL BECOME SOMEWHAT
LIGHT/VARIABLE...BEFORE BECOMING LIGHT SOUTH ON SATURDAY AS THE
SURFACE RIDGE AXIS PASSES TO THE EAST. SOUTHERLY WINDS WILL THEN
BEGIN TO INCREASE SATURDAY NIGHT AND MORE SO SUNDAY...AS LOW
PRESSURE DEVELOPS IN THE LEE OF THE NORTHERN ROCKIES AND THE
GRADIENT BEGINS TO TIGHTEN ACROSS THE PLAINS AND UPPER MIDWEST.
MEDIUM RANGE FORECAST MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING
A SUB-1000 MB SURFACE LOW ACROSS IOWA OR SOUTHERN MINNESOTA BY
MIDDAY MONDAY...WHICH WOULD LEAD TO SOUTH-SOUTHEAST WINDS IN THE
20-25 KT RANGE THROUGH MONDAY BEFORE OCCLUDING AND WEAKENING AS THE
LOW MOVES ACROSS WISCONSIN AND LAKE MICHIGAN ON TUESDAY.

HOWEVER...VARIOUS MODEL AND MODEL ENSEMBLE MEMBERS THEN DEVELOP A
SECOND LOW SOUTH OF THE LAKES ALONG THE TRAILING COLD FRONT TUESDAY
NIGHT...WHICH WOULD LIFT NORTH AND COMBINE WITH THE FILLING GREAT
LAKES LOW...DEEPENING RAPIDLY WEDNESDAY AND WEDNESDAY NIGHT OVER THE
EASTERN LAKES. THIS SCENARIO WOULD LEAD TO QUICKLY INCREASING
WESTERLY WINDS ACROSS LAKE MICHIGAN...QUITE POSSIBLY WEST GALES...
LATE WEDNESDAY INTO THURSDAY/CHRISTMAS DAY AS THE LOW PULLS AWAY TO
THE NORTHEAST.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
241 AM CST Fri Dec 19 2014

.SHORT TERM...(Today)
ISSUED AT 240 AM CST FRI DEC 19 2014

High pressure is expected to hold over central Illinois through
today with the next southern stream shortwave, currently over south
central Texas early this morning, forecast to track well south of
our area. 2am satellite data and surface observations showing an
area of clear skies extending from just northwest of Peoria
southeast thru Champaign and Decatur. Short range models suggest
this area will gradually fill back in with clouds as the day wears
on. Forecast soundings from the HRRR and Rapid Refresh models also
support this idea thru the day with the last few satellite frames
off the IR loop indicating the clouds over far west central IL were
starting to shift more to the east. Forecast soundings across
central IL today support afternoon temperatures in the low to mid
30s with another day with very little wind, something that is a bit
on the rare side for December across our area.


&&

.LONG TERM...(Tonight through Christmas Day)
ISSUED AT 240 AM CST FRI DEC 19 2014

Main focus remains with active pattern setting up for the upcoming
holiday week.

Powerful jet of 120-160 knots at 300 mb will be coming into the
Pacific Northwest later this weekend before diving toward the
southern Plains, helping to carve out a deep trough over the central
U.S. The GFS and ECMWF models are in good agreement with development
of a closed low over eastern South Dakota by midday Monday, with
some minor disagreements as to the amount of wobbling of this low as
it drifts toward the east. The ECMWF brings the center as far south
as Springfield by Wednesday morning, while the GFS and Canadian
models are centered across Wisconsin.

Precipitation shield with this system expected to start spreading
into the Illinois River valley by late Monday morning, then eastward
across the state during the day. The GFS is more prominent with a
dry slot punching in already by late evening, while the ECMWF
lingers the rain into Tuesday morning. Leaned more towards the
slower ECMWF solution and increased rain chances to around 60%
Monday night north of I-74 and east of I-57. Forecast soundings are
well above freezing up to around 850 mb, so have removed any mixed
precip wording for Monday night. Some mixture possible northwest of
the Illinois River on Tuesday, although a loss of ice crystals aloft
with the dry slot may mitigate this.

As we head toward Christmas Eve, amount of wrap-around precipitation
is a concern. The ECMWF rapidly intensifies the surface cyclone to
our east, with central pressure down to around 978 mb midday near
Cleveland. This solution brings periodic snow showers southeast into
our area in the strong northwest flow. The much weaker GFS has some
flurries lingering through the day, with less windy conditions. Have
kept precipitation chances across the east during the day on the
edge of the ECMWF`s dry slot, but kept only slight chances elsewhere
for now. Snowfall amounts still appear to be on the light side, but
holiday travel will still not be pleasant with the snow and the
winds. Christmas Day itself appears dry.


&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1118 PM CST THU DEC 18 2014

VFR conditions should last through the TAF period. Some clearing
has developed along the surface ridge axis over some of the TAF
sites already...but decided to keep few or scattered clouds since
confidence is not strong enough in clear skies over a long period
of time. Satellite shows a relatively narrow band of
clearing...with more cloud cover upstream. Winds will be calm to
light throughout the TAF period as the surface high stays over
central Illinois through tomorrow evening before slowly shifting
eastward. Winds will be variable with the high overhead and will
shift to the east southeast tomorrow night...but remain light.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...ALW







AREA FORECAST DISCUSSION

NWS DES MOINES IA

 1148 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...19/06Z
ISSUED AT 1141 PM CST THU DEC 18 2014

LOW STRATUS WILL CONTINUE TO BE WIDESPREAD FOR THE DURATION OF THE
FORECAST. VFR CONDITIONS WILL PERSIST ACRS THE FAR NORTHEAST
THROUGH MUCH OF THE NIGHT BUT THE SLOW NORTH AND EAST PROGRESSION
OF MVFR TO IFR CEILINGS WILL CONTINUE AS SOUTHERLY FLOW BEGINS TO
INCREASE AS SURFACE RIDGE SLIDES SLOWLY EASTWARD. THE MVFR TO IFR
CONDITIONS WILL PERSIST INTO FRIDAY AND FRIDAY EVENING AS THE
MOIST LOW LEVEL FLOW CONTINUES. GFS IS INDICATING SOME -DZ/-FZDZ
BY AFTERNOON ACROSS PORTIONS OF THE FORECAST AREA AS FORCING
INCREASES. HAVE NOT INCLUDED AT THIS TIME BUT WILL HAVE TO BE
MONITORED FOR INCLUSION IN SUBSEQUENT FORECASTS. SURFACE WINDS
WILL BE LIGHT OVERNIGHT BECOMING SOUTHEAST TO SOUTH ON FRIDAY BUT
REMAINING LIGHT.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...COGIL



AREA FORECAST DISCUSSION

NWS TOPEKA KS

 1202 PM CST Fri Dec 19 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 246 AM CST FRI DEC 19 2014

08Z water vapor imagery indicated there were a couple waves within a
somewhat slow split flow over the plains. The stronger wave was
lifting through the southern plains with some decent lightning noted
in eastern TX. A second weaker wave was noted over southeastern MT.
At the surface a high pressure system centered over the central and
upper MS river valley was nosing into eastern KS with a ridge axis
bisecting the forecast area.

For today and tonight, the better forcing from the shortwaves looks
to only glance the forecast area. Forecast soundings from the
RAP/NAM/GFS indicated a decent amount of dry air in the mid levels
and prog a westerly wind at 850 and above to continue advecting dry
air in from the west. So with the weak forcing unlikely to overcome
the dry air in mid levels, have maintained a dry forecast through
tonight. Really the main forecast challenge is the boundary layer
moisture and pesky stratus. All the models fall to mix out the low
level inversion and the boundary layer moisture. This seems to make
some since with the expansive stratus deck already in place and snow
cover limiting any insolation to warm surface temps. Therefore have
leaned towards an overcast sky through tonight. Isentropic surfaces
show only weak if any isentropic upglide and appear to focus this
mainly across MO, so concerns for drizzle are minimal today as well.
About the only uncertainty with the forecast is the NAM`s tendency
to over due the impact of the snow cover and keeping the boundary
layer to cool for to long. However with the GFS and RAP showing
similar solutions, think the low clouds scattering out is a low
chance occurrence. Highs today are expected to be in the mid 30s
with no real low level warm air advection and clouds holding on
strong. For tonight have kept skies cloudy, but if for some reason
we were to clear out, fog would become more likely. I don`t have a
lot of confidence in this happening. Nevertheless have added a
mention of patchy fog after midnight due to forecast soundings
showing the potential for some fog, especially across north central
KS. Lows tonight are expected to range from the mid 20 to around 30.

.LONG TERM...(Saturday through Thursday)
Issued at 246 AM CST FRI DEC 19 2014

Patchy fog is expected to linger through mid morning Saturday before
lifting to mostly cloudy stratus. A developing surface trough over
eastern CO will pick up winds around 10 mph, attempting to mix out
the stratus in the lower levels. Best chances for seeing peeks of
sunshine lie across central KS, with much of the CWA remaining
cloudy. Despite the warmer temps from guidance, believe the
lingering snow cover holds highs a few degrees cooler in north
central and far northeast KS where upper 30s are common. Areas with
little to no snow cover may reach the lower to middle 40s. Surface
trough begins to deepen on Sunday in response to the upper shortwave
trough coming onshore from the Pacific NW. Southwesterly winds
increase around 15 mph through the afternoon. A weaker lead trough
progresses over the northern plains Sunday morning, bringing a
chance for light drizzle. Freezing precip should not be a concern as
guidance is trending warmer near 40 degrees for morning lows.
Precip chances increase Sunday evening into Monday as the system
shifts east over the northern plains. Discrepancies remain on
guidance as the latest ECMWF is less amplified and impacting more
of the eastern CWA, similar to the GEM. In addition, the GFS is
more amplified from an upper jet streak rounding the southern edge
of the wave. Given this and the amount of saturation is relative
compared to previous systems, will continue with 30-40 pops until
more consistency is seen between runs. Bulk of the QPF is rain on
Monday as highs peak in the upper 40s. The freezing temps slide in
behind the departing wave where a rain and snow mix is possible
Monday evening. No accumulation is expected at this time.

An anomalous upper ridge builds eastward into the region Tuesday and
Wednesday giving the area a chance to clear out the stratus clouds.
Modified airmass in the wake of the system will only drop highs into
the low 40s for highs and lows in the upper 20s and low 30s. In
terms of Christmas Day, much uncertainty exists with the timing and
track of the next upper trough. Latest runs are trending slower with
the system, GFS being more progressive and impacting mainly north
central areas. Meanwhile the ECMWF is slower and places our area in
the dry slot. While confidence is below average, will maintain
forecast consistency with slight chances for a rain and snow mix.

&&

.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1146 AM CST FRI DEC 19 2014

IFR conditions will last through most the next 24 hours. There may
be a brief period where ceilings will rise to 1000 to 1400 feet
this afternoon. After 02Z SAT the stratus will lower to 600 to 900
feet. visibilites will rise to 6 to 8SM this afternoon but drop to
2 to 4SM after 02Z SAT.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Gargan






AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1032 AM MST FRI DEC 19 2014

.SHORT TERM...(THIS MORNING THROUGH SUNDAY NIGHT)
ISSUED AT 233 AM MST FRI DEC 19 2014

EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER OK PANHANDLE WITH SHORTWAVE RIDGE OVER THE TREAT BASIN
BUILDING EAST TOWARDS THE CENTRAL ROCKIES. AT THE SURFACE...LOW
PRESSURE REMAINS IN PLACE FROM THE NORTHERN PLAINS AND ACROSS
EASTERN COLORADO. HIGH PRESSURE IS GENERALLY IN PLACES ACROSS MUCH
OF THE CWA...WITH LOW PRESSURE BEGINNING TO BUILD IN FROM THE WEST.

EARLY THIS MORNING...AXIS OF DENSE FOG DEVELOPED LATE LAST NIGHT
GENERALLY ALONG HWY 25 AND HWY 83 CORRIDOR BEHIND STRATUS DECK TO
THE EAST. WEST OF THIS...BL HAS BEEN TOO DRY FOR DENSE FOG
DEVELOPMENT...THOUGH WITH NEARBY HIGH PRESSURE/LIGHT WINDS/CLEAR
SKIES PATCHY FOG WILL BE POSSIBLE THIS MORNING. RAP/HRRR BOTH HAVE
GOOD REFLECTION OF THE SPOTTY NATURE OF THE FOG OVER OUR CWA...AND
GENERALLY KEEP MAIN AXIS OF DENSE FOG WHERE IT IS...IMPROVING
CONDITIONS AROUND 12-13Z. DUE TO THE LOCALIZED NATURE OF THE
DENSE FOG AND GUIDANCE TRENDING AWAY FROM WIDESPREAD COVERAGE I
DECIDED TO CONTINUE WITH HANDLING THIS EVENT WITH SPS.

TODAY...ANY FOG/STRATUS SHOULD CLEAR BY MIDDAY AS SURFACE LOW SHIFTS
EAST TO THE KS/CO BORDER. THIS WILL SUPPORT TEMPS MODERATING TO THE
40S/NEAR 50 OVER MUCH OF THE CWA (COOLER IN YUMA COUNTY WHERE SNOW
PACK LINGERS).

TONIGHT-WE MAY SEE FOG REDEVELOP ACROSS NORTH CENTRAL KS...WHICH
COULD IMPACT OUR EASTERN CWA. THOUGH NAM/SREF HAVE A PRETTY GOOD
SIGNAL FOR THIS...AS LOW SHIFTS EAST AIR MASS WILL BE CHANGING WITH
LOWER BL MOISTURE PRESENT AND IM NOT AS SURE CURRENT MODEL
COVERAGE/DEPICTION IS REALISTIC. I ADDED PATCHY FREEZING FOG IN OUR
EAST AHEAD OF MAIN SURFACE TROUGH TO COVER POTENTIAL.

SATURDAY-SUNDAY...SHORTWAVE RIDGE WILL TRANSITION EASTWARD ACROSS
THE PLAINS SATURDAY/SATURDAY NIGHT WITH A TROUGH REDEVELOPING OVER
THE NORTHERN PLAINS BY SUNDAY NIGHT. AHEAD OF THIS DEVELOPING UPPER
TROUGH...SURFACE TROUGHING AND INCREASING WAA WILL SUPPORT
INCREASING TEMPS TO WELL ABOVE NORMAL. DEPENDING ON MIXING (WHICH
COULD BE LIMITED BY CLOUDS)...HIGHS BY SUNDAY SHOULD BE IN MIDDLE
50S WITH DECREASING IMPACT FROM SNOW PACK IN THE NORTHWEST AS IT
CONTINUES TO DEGRADE OVER THE NEXT FEW DAYS. I COULD ACTUALLY SEE
SOME LOCATIONS APPROACH THE UPPER 50S SUNDAY BASED ON CURRENT
925/850 MB TEMPS.

SUNDAY NIGHT...LOBES OF MID LEVEL VORTICITY COMBINED WITH INCREASING
FRONTOGENETIC FORCING COULD SUPPORT SEVERAL BANDS OF LIGHT
PRECIPITATION MOVING INTO OUR CWA BY SUNDAY NIGHT. MODELS ARE
SHOWING A GOOD DRY LAYER THAT ANY PRECIP WOULD HAVE TO SATURATE
THROUGH. TEMP PROFILES GENERALLY SUPPORT RAIN...WITH SATURATION TO
WET BULB TEMPS NEAR A RAIN OR RAIN/SNOW MIX LATE SUNDAY NIGHT. DUE
TO UNCERTAINTY OF MEASURABLE DUE TO DRY LAYER AND POSITION OF
THESE BANDS...I KEPT POP MENTION LIMITED TO SLIGHT CHANCE.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 233 AM MST FRI DEC 19 2014

AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE CENTRAL PLAINS REGION
MONDAY...BRINGING CHANCES FOR RAIN AND SNOW SHOWERS.  BASED ON THE
LOWER LEVEL TEMPERATURE FIELD...CRITICAL THICKNESSES AND WET BULB
ZERO HEIGHTS...EXPECTING NORTHWEST PORTIONS OF THE FORECAST AREA TO
START AS A RAIN/SNOW MIX.  OTHERWISE...ALL OTHER AREAS WILL RECEIVE
RAIN MONDAY MORNING.  ALTHOUGH THERE IS STRONG NORTHWEST FLOW ALOFT
WITH COOLER TEMPERATURES BEING ADVECTED INTO THE AREA...SURFACE
TEMPERATURES WILL WARM INTO THE MID TO UPPER 40S IN THE AFTERNOON.
THIS SURFACE WARMING WILL ALLOW RAIN TO BE THE PRIMARY PRECIPITATION
TYPE IN THE AFTERNOON.  PRECIPITATION WILL CHANGE BACK TO SNOW AFTER
SUNSET.  ECMWF AND GFS MODELS ARE FORECASTING BETWEEN 1 AND 2 INCHES
OF SNOW...HOWEVER CONFIDENCE IS LOW IN THOSE FORECAST AMOUNTS DUE TO
RUNNING ACCUMULATIONS IN PERIODS OF PHASE CHANGE. THEREFORE...THE
FORECAST REFLECTS TOTAL VALUES LESS THAN AN INCH AT THIS TIME.

A SHORTWAVE RIDGE WILL BUILD INTO THE TRI STATE AREA TUESDAY AND
WEDNESDAY...BRINGING DRY CONDITIONS AND NEAR NORMAL HIGH
TEMPERATURES IN THE LOW TO UPPER 40S.  BLENDED POP FORECAST WAS
HINTING AT PRECIPITATION CHANCES THROUGH THE DAY TUESDAY...BUT
DECIDED TO ELIMINATE POPS DUE TO THE 500 MB AXIS BEING THROUGH THE
FORECAST AREA BY 18Z TUESDAY.

THE NEXT WEATHER SYSTEM TO APPROACH THE REGION WILL COME FROM THE
PACIFIC NORTHWEST CHRISTMAS EVE THROUGH CHRISTMAS DAY.  ALTHOUGH
THIS SYSTEM IS STILL A FEW DAYS OUT...GUIDANCE IS SEEMINGLY SLOWING
THE PROGRESSION OF THE SYSTEM INTO THE AREA TOWARDS A THURSDAY NIGHT
OR FRIDAY ARRIVAL. A GENERAL NORTHWEST FLOW WILL BRING MOISTURE IN
FROM THE PACIFIC NORTHWEST MAINLY ON THE NORTHERN COLD SIDE OF THE
SURFACE LOW...WHICH WILL BRING CHANCES FOR SNOW SHOWERS.  AT THIS
TIME...THINKING A LITTLE OVER AN INCH CAN BE EXPECTED FOR AREAS
NORTH OF INTERSTATE 70.  THIS AMOUNT IS LIKELY TO CHANGE WITH FUTURE
FORECASTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1025 AM MST FRI DEC 19 2014

VFR CONDITIONS ARE EXPECTED AT KGLD AND KMCK FOR THE NEXT 24
HOURS AS HIGH PRESSURE OVER THE CENTRAL PLAINS SLOWLY DRIFTS EAST
AND A WEAK TROUGH MOVES INTO EASTERN COLORADO SATURDAY AFTERNOON.
THE NAM FORECAST SOUNDING FOR KMCK INDICATES THE POSSIBILITY OF
SOME SHALLOW STRATUS OR LIGHT FOG EARLY SATURDAY MORNING. HOWEVER
DEWPOINT TRENDS ARE DECREASING THROUGH THE NIGHT AS WEST WIND
ADVECTS DRIER AIR INTO THE AREA. PLAN ON LEAVING STRATUS/LIGHT
FOG OUT FOR NOW.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...FS



AREA FORECAST DISCUSSION

NWS GOODLAND KS

 428 AM MST FRI DEC 19 2014

.SHORT TERM...(THIS MORNING THROUGH SUNDAY NIGHT)
ISSUED AT 233 AM MST FRI DEC 19 2014

EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER OK PANHANDLE WITH SHORTWAVE RIDGE OVER THE TREAT BASIN
BUILDING EAST TOWARDS THE CENTRAL ROCKIES. AT THE SURFACE...LOW
PRESSURE REMAINS IN PLACE FROM THE NORTHERN PLAINS AND ACROSS
EASTERN COLORADO. HIGH PRESSURE IS GENERALLY IN PLACES ACROSS MUCH
OF THE CWA...WITH LOW PRESSURE BEGINNING TO BUILD IN FROM THE WEST.

EARLY THIS MORNING...AXIS OF DENSE FOG DEVELOPED LATE LAST NIGHT
GENERALLY ALONG HWY 25 AND HWY 83 CORRIDOR BEHIND STRATUS DECK TO
THE EAST. WEST OF THIS...BL HAS BEEN TOO DRY FOR DENSE FOG
DEVELOPMENT...THOUGH WITH NEARBY HIGH PRESSURE/LIGHT WINDS/CLEAR
SKIES PATCHY FOG WILL BE POSSIBLE THIS MORNING. RAP/HRRR BOTH HAVE
GOOD REFLECTION OF THE SPOTTY NATURE OF THE FOG OVER OUR CWA...AND
GENERALLY KEEP MAIN AXIS OF DENSE FOG WHERE IT IS...IMPROVING
CONDITIONS AROUND 12-13Z. DUE TO THE LOCALIZED NATURE OF THE
DENSE FOG AND GUIDANCE TRENDING AWAY FROM WIDESPREAD COVERAGE I
DECIDED TO CONTINUE WITH HANDLING THIS EVENT WITH SPS.

TODAY...ANY FOG/STRATUS SHOULD CLEAR BY MIDDAY AS SURFACE LOW SHIFTS
EAST TO THE KS/CO BORDER. THIS WILL SUPPORT TEMPS MODERATING TO THE
40S/NEAR 50 OVER MUCH OF THE CWA (COOLER IN YUMA COUNTY WHERE SNOW
PACK LINGERS).

TONIGHT-WE MAY SEE FOG REDEVELOP ACROSS NORTH CENTRAL KS...WHICH
COULD IMPACT OUR EASTERN CWA. THOUGH NAM/SREF HAVE A PRETTY GOOD
SIGNAL FOR THIS...AS LOW SHIFTS EAST AIR MASS WILL BE CHANGING WITH
LOWER BL MOISTURE PRESENT AND IM NOT AS SURE CURRENT MODEL
COVERAGE/DEPICTION IS REALISTIC. I ADDED PATCHY FREEZING FOG IN OUR
EAST AHEAD OF MAIN SURFACE TROUGH TO COVER POTENTIAL.

SATURDAY-SUNDAY...SHORTWAVE RIDGE WILL TRANSITION EASTWARD ACROSS
THE PLAINS SATURDAY/SATURDAY NIGHT WITH A TROUGH REDEVELOPING OVER
THE NORTHERN PLAINS BY SUNDAY NIGHT. AHEAD OF THIS DEVELOPING UPPER
TROUGH...SURFACE TROUGHING AND INCREASING WAA WILL SUPPORT
INCREASING TEMPS TO WELL ABOVE NORMAL. DEPENDING ON MIXING (WHICH
COULD BE LIMITED BY CLOUDS)...HIGHS BY SUNDAY SHOULD BE IN MIDDLE
50S WITH DECREASING IMPACT FROM SNOW PACK IN THE NORTHWEST AS IT
CONTINUES TO DEGRADE OVER THE NEXT FEW DAYS. I COULD ACTUALLY SEE
SOME LOCATIONS APPROACH THE UPPER 50S SUNDAY BASED ON CURRENT
925/850 MB TEMPS.

SUNDAY NIGHT...LOBES OF MID LEVEL VORTICITY COMBINED WITH INCREASING
FRONTOGENETIC FORCING COULD SUPPORT SEVERAL BANDS OF LIGHT
PRECIPITATION MOVING INTO OUR CWA BY SUNDAY NIGHT. MODELS ARE
SHOWING A GOOD DRY LAYER THAT ANY PRECIP WOULD HAVE TO SATURATE
THROUGH. TEMP PROFILES GENERALLY SUPPORT RAIN...WITH SATURATION TO
WET BULB TEMPS NEAR A RAIN OR RAIN/SNOW MIX LATE SUNDAY NIGHT. DUE
TO UNCERTAINTY OF MEASURABLE DUE TO DRY LAYER AND POSITION OF
THESE BANDS...I KEPT POP MENTION LIMITED TO SLIGHT CHANCE.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 233 AM MST FRI DEC 19 2014

AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE CENTRAL PLAINS REGION
MONDAY...BRINGING CHANCES FOR RAIN AND SNOW SHOWERS.  BASED ON THE
LOWER LEVEL TEMPERATURE FIELD...CRITICAL THICKNESSES AND WET BULB
ZERO HEIGHTS...EXPECTING NORTHWEST PORTIONS OF THE FORECAST AREA TO
START AS A RAIN/SNOW MIX.  OTHERWISE...ALL OTHER AREAS WILL RECEIVE
RAIN MONDAY MORNING.  ALTHOUGH THERE IS STRONG NORTHWEST FLOW ALOFT
WITH COOLER TEMPERATURES BEING ADVECTED INTO THE AREA...SURFACE
TEMPERATURES WILL WARM INTO THE MID TO UPPER 40S IN THE AFTERNOON.
THIS SURFACE WARMING WILL ALLOW RAIN TO BE THE PRIMARY PRECIPITATION
TYPE IN THE AFTERNOON.  PRECIPITATION WILL CHANGE BACK TO SNOW AFTER
SUNSET.  ECMWF AND GFS MODELS ARE FORECASTING BETWEEN 1 AND 2 INCHES
OF SNOW...HOWEVER CONFIDENCE IS LOW IN THOSE FORECAST AMOUNTS DUE TO
RUNNING ACCUMULATIONS IN PERIODS OF PHASE CHANGE. THEREFORE...THE
FORECAST REFLECTS TOTAL VALUES LESS THAN AN INCH AT THIS TIME.

A SHORTWAVE RIDGE WILL BUILD INTO THE TRI STATE AREA TUESDAY AND
WEDNESDAY...BRINGING DRY CONDITIONS AND NEAR NORMAL HIGH
TEMPERATURES IN THE LOW TO UPPER 40S.  BLENDED POP FORECAST WAS
HINTING AT PRECIPITATION CHANCES THROUGH THE DAY TUESDAY...BUT
DECIDED TO ELIMINATE POPS DUE TO THE 500 MB AXIS BEING THROUGH THE
FORECAST AREA BY 18Z TUESDAY.

THE NEXT WEATHER SYSTEM TO APPROACH THE REGION WILL COME FROM THE
PACIFIC NORTHWEST CHRISTMAS EVE THROUGH CHRISTMAS DAY.  ALTHOUGH
THIS SYSTEM IS STILL A FEW DAYS OUT...GUIDANCE IS SEEMINGLY SLOWING
THE PROGRESSION OF THE SYSTEM INTO THE AREA TOWARDS A THURSDAY NIGHT
OR FRIDAY ARRIVAL. A GENERAL NORTHWEST FLOW WILL BRING MOISTURE IN
FROM THE PACIFIC NORTHWEST MAINLY ON THE NORTHERN COLD SIDE OF THE
SURFACE LOW...WHICH WILL BRING CHANCES FOR SNOW SHOWERS.  AT THIS
TIME...THINKING A LITTLE OVER AN INCH CAN BE EXPECTED FOR AREAS
NORTH OF INTERSTATE 70.  THIS AMOUNT IS LIKELY TO CHANGE WITH FUTURE
FORECASTS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 427 AM MST FRI DEC 19 2014

DENSE FREEZING FOG WITH 1/4 SM VIS HAD CONTINUED AT KMCK MOST OF
THE OVERNIGHT PERIOD...WITH RECENT TRENDS THIS HOUR SHOWING SLIGHT
IMPROVEMENT. GUIDANCE INDICATES FOG WILL BEGIN TO ERODE AROUND
SUNRISE...WITH VFR CONDITIONS EXPECTED BY MIDDAY. WESTERLY WINDS
HAVE HELPED KEEP LOW LEVELS MIXED AT KGLD AND VFR CONDITIONS IN
PLACE. IF WINDS WERE TO GO CALM AROUND SUNSET I COULD SEE FOG
DEVELOPING...HOWEVER SHORT RANGE GUIDANCE IS FAVORING VFR AT KGLD
WITH ANY FOG REMAINING OUTSIDE OF THE VICINITY OF THE TERMINAL.
WILL NEED TO MONITOR 12-15Z AS THAT WILL WILL BE WINDOW FOR
POSSIBLE FOG DEVELOPMENT. WINDS WILL REMAIN AROUND 7KT FROM THE
SOUTHWEST FOR MOST OF THE TAF PERIOD AT BOTH TERMINALS.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...DR



AREA FORECAST DISCUSSION

NWS TOPEKA KS

 518 AM CST Fri Dec 19 2014

...AVIATION UPDATE...

.SHORT TERM...(Today and Tonight)
Issued at 246 AM CST FRI DEC 19 2014

08Z water vapor imagery indicated there were a couple waves within a
somewhat slow split flow over the plains. The stronger wave was
lifting through the southern plains with some decent lightning noted
in eastern TX. A second weaker wave was noted over southeastern MT.
At the surface a high pressure system centered over the central and
upper MS river valley was nosing into eastern KS with a ridge axis
bisecting the forecast area.

For today and tonight, the better forcing from the shortwaves looks
to only glance the forecast area. Forecast soundings from the
RAP/NAM/GFS indicated a decent amount of dry air in the mid levels
and prog a westerly wind at 850 and above to continue advecting dry
air in from the west. So with the weak forcing unlikely to overcome
the dry air in mid levels, have maintained a dry forecast through
tonight. Really the main forecast challenge is the boundary layer
moisture and pesky stratus. All the models fall to mix out the low
level inversion and the boundary layer moisture. This seems to make
some since with the expansive stratus deck already in place and snow
cover limiting any insolation to warm surface temps. Therefore have
leaned towards an overcast sky through tonight. Isentropic surfaces
show only weak if any isentropic upglide and appear to focus this
mainly across MO, so concerns for drizzle are minimal today as well.
About the only uncertainty with the forecast is the NAM`s tendency
to over due the impact of the snow cover and keeping the boundary
layer to cool for to long. However with the GFS and RAP showing
similar solutions, think the low clouds scattering out is a low
chance occurrence. Highs today are expected to be in the mid 30s
with no real low level warm air advection and clouds holding on
strong. For tonight have kept skies cloudy, but if for some reason
we were to clear out, fog would become more likely. I don`t have a
lot of confidence in this happening. Nevertheless have added a
mention of patchy fog after midnight due to forecast soundings
showing the potential for some fog, especially across north central
KS. Lows tonight are expected to range from the mid 20 to around 30.

.LONG TERM...(Saturday through Thursday)
Issued at 246 AM CST FRI DEC 19 2014

Patchy fog is expected to linger through mid morning Saturday before
lifting to mostly cloudy stratus. A developing surface trough over
eastern CO will pick up winds around 10 mph, attempting to mix out
the stratus in the lower levels. Best chances for seeing peeks of
sunshine lie across central KS, with much of the CWA remaining
cloudy. Despite the warmer temps from guidance, believe the
lingering snow cover holds highs a few degrees cooler in north
central and far northeast KS where upper 30s are common. Areas with
little to no snow cover may reach the lower to middle 40s. Surface
trough begins to deepen on Sunday in response to the upper shortwave
trough coming onshore from the Pacific NW. Southwesterly winds
increase around 15 mph through the afternoon. A weaker lead trough
progresses over the northern plains Sunday morning, bringing a
chance for light drizzle. Freezing precip should not be a concern as
guidance is trending warmer near 40 degrees for morning lows.
Precip chances increase Sunday evening into Monday as the system
shifts east over the northern plains. Discrepancies remain on
guidance as the latest ECMWF is less amplified and impacting more
of the eastern CWA, similar to the GEM. In addition, the GFS is
more amplified from an upper jet streak rounding the southern edge
of the wave. Given this and the amount of saturation is relative
compared to previous systems, will continue with 30-40 pops until
more consistency is seen between runs. Bulk of the QPF is rain on
Monday as highs peak in the upper 40s. The freezing temps slide in
behind the departing wave where a rain and snow mix is possible
Monday evening. No accumulation is expected at this time.

An anomalous upper ridge builds eastward into the region Tuesday and
Wednesday giving the area a chance to clear out the stratus clouds.
Modified airmass in the wake of the system will only drop highs into
the low 40s for highs and lows in the upper 20s and low 30s. In
terms of Christmas Day, much uncertainty exists with the timing and
track of the next upper trough. Latest runs are trending slower with
the system, GFS being more progressive and impacting mainly north
central areas. Meanwhile the ECMWF is slower and places our area in
the dry slot. While confidence is below average, will maintain
forecast consistency with slight chances for a rain and snow mix.

&&

.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 518 AM CST FRI DEC 19 2014

Uncertainty hings mainly on what the CIGS will do. Have continued
with the prev forecast idea of CIGS gradually improving above 1
KFT this afternoon. Have timed this with the passage of the
surface ridge axis, thinking southerly winds around 5KT could aid
in boundary layer mixing and cause the CIGS to lift. Since none of
the forecast soundings mix out the low level inversion this
afternoon, think IFR CIGS are likely to return overnight.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Wolters







AREA FORECAST DISCUSSION...CORRECTED

NWS GOODLAND KS

 234 AM MST FRI DEC 19 2014

.SHORT TERM...(THIS MORNING THROUGH SUNDAY NIGHT)
ISSUED AT 233 AM MST FRI DEC 19 2014

EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER OK PANHANDLE WITH SHORTWAVE RIDGE OVER THE TREAT BASIN
BUILDING EAST TOWARDS THE CENTRAL ROCKIES. AT THE SURFACE...LOW
PRESSURE REMAINS IN PLACE FROM THE NORTHERN PLAINS AND ACROSS
EASTERN COLORADO. HIGH PRESSURE IS GENERALLY IN PLACES ACROSS MUCH
OF THE CWA...WITH LOW PRESSURE BEGINNING TO BUILD IN FROM THE WEST.

EARLY THIS MORNING...AXIS OF DENSE FOG DEVELOPED LATE LAST NIGHT
GENERALLY ALONG HWY 25 AND HWY 83 CORRIDOR BEHIND STRATUS DECK TO
THE EAST. WEST OF THIS...BL HAS BEEN TOO DRY FOR DENSE FOG
DEVELOPMENT...THOUGH WITH NEARBY HIGH PRESSURE/LIGHT WINDS/CLEAR
SKIES PATCHY FOG WILL BE POSSIBLE THIS MORNING. RAP/HRRR BOTH HAVE
GOOD REFLECTION OF THE SPOTTY NATURE OF THE FOG OVER OUR CWA...AND
GENERALLY KEEP MAIN AXIS OF DENSE FOG WHERE IT IS...IMPROVING
CONDITIONS AROUND 12-13Z. DUE TO THE LOCALIZED NATURE OF THE
DENSE FOG AND GUIDANCE TRENDING AWAY FROM WIDESPREAD COVERAGE I
DECIDED TO CONTINUE WITH HANDLING THIS EVENT WITH SPS.

TODAY...ANY FOG/STRATUS SHOULD CLEAR BY MIDDAY AS SURFACE LOW SHIFTS
EAST TO THE KS/CO BORDER. THIS WILL SUPPORT TEMPS MODERATING TO THE
40S/NEAR 50 OVER MUCH OF THE CWA (COOLER IN YUMA COUNTY WHERE SNOW
PACK LINGERS).

TONIGHT-WE MAY SEE FOG REDEVELOP ACROSS NORTH CENTRAL KS...WHICH
COULD IMPACT OUR EASTERN CWA. THOUGH NAM/SREF HAVE A PRETTY GOOD
SIGNAL FOR THIS...AS LOW SHIFTS EAST AIR MASS WILL BE CHANGING WITH
LOWER BL MOISTURE PRESENT AND IM NOT AS SURE CURRENT MODEL
COVERAGE/DEPICTION IS REALISTIC. I ADDED PATCHY FREEZING FOG IN OUR
EAST AHEAD OF MAIN SURFACE TROUGH TO COVER POTENTIAL.

SATURDAY-SUNDAY...SHORTWAVE RIDGE WILL TRANSITION EASTWARD ACROSS
THE PLAINS SATURDAY/SATURDAY NIGHT WITH A TROUGH REDEVELOPING OVER
THE NORTHERN PLAINS BY SUNDAY NIGHT. AHEAD OF THIS DEVELOPING UPPER
TROUGH...SURFACE TROUGHING AND INCREASING WAA WILL SUPPORT
INCREASING TEMPS TO WELL ABOVE NORMAL. DEPENDING ON MIXING (WHICH
COULD BE LIMITED BY CLOUDS)...HIGHS BY SUNDAY SHOULD BE IN MIDDLE
50S WITH DECREASING IMPACT FROM SNOW PACK IN THE NORTHWEST AS IT
CONTINUES TO DEGRADE OVER THE NEXT FEW DAYS. I COULD ACTUALLY SEE
SOME LOCATIONS APPROACH THE UPPER 50S SUNDAY BASED ON CURRENT
925/850 MB TEMPS.

SUNDAY NIGHT...LOBES OF MID LEVEL VORTICITY COMBINED WITH INCREASING
FRONTOGENETIC FORCING COULD SUPPORT SEVERAL BANDS OF LIGHT
PRECIPITATION MOVING INTO OUR CWA BY SUNDAY NIGHT. MODELS ARE
SHOWING A GOOD DRY LAYER THAT ANY PRECIP WOULD HAVE TO SATURATE
THROUGH. TEMP PROFILES GENERALLY SUPPORT RAIN...WITH SATURATION TO
WET BULB TEMPS NEAR A RAIN OR RAIN/SNOW MIX LATE SUNDAY NIGHT. DUE
TO UNCERTAINTY OF MEASURABLE DUE TO DRY LAYER AND POSITION OF
THESE BANDS...I KEPT POP MENTION LIMITED TO SLIGHT CHANCE.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 233 AM MST FRI DEC 19 2014

AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE CENTRAL PLAINS REGION
MONDAY...BRINGING CHANCES FOR RAIN AND SNOW SHOWERS.  BASED ON THE
LOWER LEVEL TEMPERATURE FIELD...CRITICAL THICKNESSES AND WET BULB
ZERO HEIGHTS...EXPECTING NORTHWEST PORTIONS OF THE FORECAST AREA TO
START AS A RAIN/SNOW MIX.  OTHERWISE...ALL OTHER AREAS WILL RECEIVE
RAIN MONDAY MORNING.  ALTHOUGH THERE IS STRONG NORTHWEST FLOW ALOFT
WITH COOLER TEMPERATURES BEING ADVECTED INTO THE AREA...SURFACE
TEMPERATURES WILL WARM INTO THE MID TO UPPER 40S IN THE AFTERNOON.
THIS SURFACE WARMING WILL ALLOW RAIN TO BE THE PRIMARY PRECIPITATION
TYPE IN THE AFTERNOON.  PRECIPITATION WILL CHANGE BACK TO SNOW AFTER
SUNSET.  ECMWF AND GFS MODELS ARE FORECASTING BETWEEN 1 AND 2 INCHES
OF SNOW...HOWEVER CONFIDENCE IS LOW IN THOSE FORECAST AMOUNTS DUE TO
RUNNING ACCUMULATIONS IN PERIODS OF PHASE CHANGE. THEREFORE...THE
FORECAST REFLECTS TOTAL VALUES LESS THAN AN INCH AT THIS TIME.

A SHORTWAVE RIDGE WILL BUILD INTO THE TRI STATE AREA TUESDAY AND
WEDNESDAY...BRINGING DRY CONDITIONS AND NEAR NORMAL HIGH
TEMPERATURES IN THE LOW TO UPPER 40S.  BLENDED POP FORECAST WAS
HINTING AT PRECIPITATION CHANCES THROUGH THE DAY TUESDAY...BUT
DECIDED TO ELIMINATE POPS DUE TO THE 500 MB AXIS BEING THROUGH THE
FORECAST AREA BY 18Z TUESDAY.

THE NEXT WEATHER SYSTEM TO APPROACH THE REGION WILL COME FROM THE
PACIFIC NORTHWEST CHRISTMAS EVE THROUGH CHRISTMAS DAY.  ALTHOUGH
THIS SYSTEM IS STILL A FEW DAYS OUT...GUIDANCE IS SEEMINGLY SLOWING
THE PROGRESSION OF THE SYSTEM INTO THE AREA TOWARDS A THURSDAY NIGHT
OR FRIDAY ARRIVAL. A GENERAL NORTHWEST FLOW WILL BRING MOISTURE IN
FROM THE PACIFIC NORTHWEST MAINLY ON THE NORTHERN COLD SIDE OF THE
SURFACE LOW...WHICH WILL BRING CHANCES FOR SNOW SHOWERS.  AT THIS
TIME...THINKING A LITTLE OVER AN INCH CAN BE EXPECTED FOR AREAS
NORTH OF INTERSTATE 70.  THIS AMOUNT IS LIKELY TO CHANGE WITH FUTURE
FORECASTS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1037 PM MST THU DEC 18 2014

FOR KGLD THRU 13Z FRIDAY VFR/MVFR MIX WITH 3-6SM IN FOG WITH
BKN060 AND KMCK...THRU 15Z FRI...WILL HAVE A MIX OF IFR AND BELOW
AS FOG WILL BRING VISIBILITY RANGING 2SM DOWN TO 1/4SM AT TIMES
AND CEILINGS RANGING FROM OVC002-010. BUT AFT 13Z-15Z THIS MORNING
BOTH SITES VFR WITH SCT100-150. WINDS VARIABLE AN LIGHT THRU 13Z-
15Z...THEN WSW 5-10KTS.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...JN



AREA FORECAST DISCUSSION

NWS TOPEKA KS

 248 AM CST Fri Dec 19 2014

.SHORT TERM...(Today and Tonight)
Issued at 246 AM CST FRI DEC 19 2014

08Z water vapor imagery indicated there were a couple waves within a
somewhat slow split flow over the plains. The stronger wave was
lifting through the southern plains with some decent lightning noted
in eastern TX. A second weaker wave was noted over southeastern MT.
At the surface a high pressure system centered over the central and
upper MS river valley was nosing into eastern KS with a ridge axis
bisecting the forecast area.

For today and tonight, the better forcing from the shortwaves looks
to only glance the forecast area. Forecast soundings from the
RAP/NAM/GFS indicated a decent amount of dry air in the mid levels
and prog a westerly wind at 850 and above to continue advecting dry
air in from the west. So with the weak forcing unlikely to overcome
the dry air in mid levels, have maintained a dry forecast through
tonight. Really the main forecast challenge is the boundary layer
moisture and pesky stratus. All the models fall to mix out the low
level inversion and the boundary layer moisture. This seems to make
some since with the expansive stratus deck already in place and snow
cover limiting any insolation to warm surface temps. Therefore have
leaned towards an overcast sky through tonight. Isentropic surfaces
show only weak if any isentropic upglide and appear to focus this
mainly across MO, so concerns for drizzle are minimal today as well.
About the only uncertainty with the forecast is the NAM`s tendency
to over due the impact of the snow cover and keeping the boundary
layer to cool for to long. However with the GFS and RAP showing
similar solutions, think the low clouds scattering out is a low
chance occurrence. Highs today are expected to be in the mid 30s
with no real low level warm air advection and clouds holding on
strong. For tonight have kept skies cloudy, but if for some reason
we were to clear out, fog would become more likely. I don`t have a
lot of confidence in this happening. Nevertheless have added a
mention of patchy fog after midnight due to forecast soundings
showing the potential for some fog, especially across north central
KS. Lows tonight are expected to range from the mid 20 to around 30.

.LONG TERM...(Saturday through Thursday)
Issued at 246 AM CST FRI DEC 19 2014

Patchy fog is expected to linger through mid morning Saturday before
lifting to mostly cloudy stratus. A developing surface trough over
eastern CO will pick up winds around 10 mph, attempting to mix out
the stratus in the lower levels. Best chances for seeing peeks of
sunshine lie across central KS, with much of the CWA remaining
cloudy. Despite the warmer temps from guidance, believe the
lingering snow cover holds highs a few degrees cooler in north
central and far northeast KS where upper 30s are common. Areas with
little to no snow cover may reach the lower to middle 40s. Surface
trough begins to deepen on Sunday in response to the upper shortwave
trough coming onshore from the Pacific NW. Southwesterly winds
increase around 15 mph through the afternoon. A weaker lead trough
progresses over the northern plains Sunday morning, bringing a
chance for light drizzle. Freezing precip should not be a concern as
guidance is trending warmer near 40 degrees for morning lows.
Precip chances increase Sunday evening into Monday as the system
shifts east over the northern plains. Discrepancies remain on
guidance as the latest ECMWF is less amplified and impacting more
of the eastern CWA, similar to the GEM. In addition, the GFS is
more amplified from an upper jet streak rounding the southern edge
of the wave. Given this and the amount of saturation is relative
compared to previous systems, will continue with 30-40 pops until
more consistency is seen between runs. Bulk of the QPF is rain on
Monday as highs peak in the upper 40s. The freezing temps slide in
behind the departing wave where a rain and snow mix is possible
Monday evening. No accumulation is expected at this time.

An anomalous upper ridge builds eastward into the region Tuesday and
Wednesday giving the area a chance to clear out the stratus clouds.
Modified airmass in the wake of the system will only drop highs into
the low 40s for highs and lows in the upper 20s and low 30s. In
terms of Christmas Day, much uncertainty exists with the timing and
track of the next upper trough. Latest runs are trending slower with
the system, GFS being more progressive and impacting mainly north
central areas. Meanwhile the ECMWF is slower and places our area in
the dry slot. While confidence is below average, will maintain
forecast consistency with slight chances for a rain and snow mix.

&&

.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1120 PM CST THU DEC 18 2014

Low stratus of 600 to 900 feet will continue across the terminals
for most of the next 24 hours. There is a chance for LIFR
conditions at KFOE as ceilings may fall to 400 feet. Areas of light
fog may also reduce visiblities. The patchy freezing drizzle
chances are decreasing after 9Z. The terminals may briefly have
low-MVFR ceilings late Friday afternoon but may go below IFR after
00Z SAT.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Gargan






AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 255 PM EST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EST FRI DEC 19 2014

A FAIRLY QUIET PATTERN IN THE CENTRAL PART OF THE CONUS...AS THE
SOUTHERN STREAM JET IS SITUATED OVER THE SOUTHERN TIER OF STATES
AND THE SYSTEM THAT BROUGHT SNOW TO THE AREA THIS PAST
TUESDAY/WEDNESDAY IS NOW SPINNING OVER PRINCE EDWARD ISLAND. CLOSER
TO THIS AREA...AN UPPER RIDGE STRETCHES FROM WISCONSIN TO JAMES
BAY...WHILE A UPPER TROUGH IS LOCATED OVER SASKATCHEWAN AND THE
NORTHERN PLAINS. BENEATH THE UPPER RIDGE...1028MB HIGH PRESSURE IS
CENTERED OVER NORTHERN LAKE SUPERIOR WITH A RIDGE STRETCHING SOUTH
THROUGH THE MID MISSISSIPPI VALLEY. THERE IS PLENTY OF DRY AIR ALOFT
ON THE RAP ANALYSIS ASSOCIATED WITH THIS UPPER RIDGE...BUT THE
SUBSIDENCE HAS STRENGTHENED THE INVERSION OVER THE GREAT LAKES AND
UPPER MISSISSIPPI VALLEY REGIONS AND AIDED IN AREAS OF LOW CLOUDS.
THE LARGEST AREA OF LOW CLOUDS COVERS MUCH OF MINNESOTA AND WESTERN
WISCONSIN...WITH THE EASTERN EDGE STRETCHING FROM GRAND MARAIS
MINNESOTA THROUGH IRONWOOD MICHIGAN AND TOWARDS MADISON WISCONSIN.
BUT THERE IS A POCKET OF CLOUDS THAT DEVELOPED OVER SOUTH CENTRAL
LAKE SUPERIOR LATE THIS EVENING (AIDED BY MARGINAL DELTA-T VALUES
FOR LAKE CLOUDS) AND WITH THE LIGHT NORTHERLY FLOW...SHIFTED INTO
THE KEWEENAW AND NORTH CENTRAL U.P.  DEFINITELY HAVE TO GIVE SOME
CREDIT TO THE REGIONAL GEM...WHICH SUPERBLY PICKED UP ON THESE
CLOUDS WITH THE 00Z RUN YESTERDAY. THESE CLOUDS ALLOWED TEMPERATURES
TO QUICKLY RISE AROUND 10 DEGREES AND LOCATIONS UNDER THEM ARE IN
THE MID-UPPER TEENS. ELSEWHERE IN THE U.P. SKIES ARE CLEAR AND WITH
THE LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOWER SINGLE
DIGITS ABOVE AND BELOW ZERO.

THE UPPER RIDGE AND SURFACE HIGH CURRENTLY OVER THE AREA WILL
SLOWLY SHIFT EAST-SOUTHEAST TODAY AND TONIGHT...ALLOWING THE AREA
TO COME UNDER GREATER INFLUENCE OF THE WEAK UPPER TROUGH. THE LOW
CLOUDS WILL BE THE PRIMARY CONCERN FOR THE FORECAST FOR TODAY. WITH
GENERALLY LIGHT WINDS AND A RELATIVELY LOW SUN ANGLE...GETTING A
HANDLE ON THE LOW CLOUDS OVER THE NORTH CENTRAL AND KEWEENAW IS
DIFFICULT. FOLLOWING 925MB WINDS IN THE MODELS...WOULD EXPECT THEM
TO TRY TO NOSE A LITTLE FARTHER INLAND OVER THE CENTRAL (AND EVEN
THE EASTERN) PART OF THE U.P. TODAY...WHILE THE DEVELOPING LIGHT
SOUTHERLY FLOW WOULD LIKELY PULL DRIER AIR BACK INTO THE KEWEENAW
AND PUSH THOSE CLOUDS NORTH. BUT THAT INCREASING SOUTHERLY FLOW
WILL ALSO PULL THE CLOUDS RIGHT NEAR IRONWOOD INTO THE REST OF
GOGEBIC AND ONTONAGON COUNTIES THROUGH THE DAY TODAY...EVENTUALLY
REACHING IRON/HOUGHTON COUNTIES THIS EVENING AS THE LIMITED MIXING
DECREASES AND THE STRATUS CAN REALLY EXPAND. THESE LOW CLOUDS
(ALONG WITH MID CLOUDS FROM THE WEAK UPPER TROUGH AXIS SHIFTING EAST
INTO MINNESOTA) WILL CONTINUE TO SPREAD ACROSS UPPER MICHIGAN FROM
SOUTHWEST TO NORTHEAST TONIGHT AS SOUTHWESTERLY FLOW GRADUALLY
DEVELOPS.

AS FOR TEMPERATURES...EVEN WITH THE COLD START THIS MORNING IN
SOME LOCATIONS...EXPECT ANOTHER DAY OF HIGHS A LITTLE BIT
ABOVE NORMAL (UPPER 20S TO LOWER 30S). THE LOWS TONIGHT WILL BE
TRICKY...AS THEY DEPEND ON THE LOCATIONS OF THE CLOUD COVER. WHERE
SKIES ARE CLEAR OVER THE CENTRAL AND EAST...WOULD EXPECT ANOTHER
QUICK DROP TO TEMPS IN THE EVENING AND NEARING 0 UNDER LIGHT WINDS.
BUT WHERE THERE ARE CLOUDS...TEMPS WILL STRUGGLE TO FALL INTO THE
MID TEENS. WILL KEEP LOWS UP THE HIGHEST OVER THE FAR WEST...WHERE
THE CLOUDS WILL MOST LIKELY BE LOCATED.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 254 PM EST FRI DEC 19 2014

NAM SHOWS A 500 MB TROUGH OVER THE UPPER GREAT LAKES 00Z SUN WITH A
CLOSED LOW OVER WESTERN ONTARIO WITH A SHORTWAVE OVER THE CANADIAN
PRAIRIES. THIS SHORTWAVE DIGS SOUTHEAST AND FORMS A CLOSED 500 MB
LOW OVER THE UPPER MISSISSIPPI RIVER VALLEY 00Z TUE.

KEPT SAT NIGHT THROUGH SUN MORNING DRY WITH PCPN OFF TO THE WEST AND
NORTHWEST OF THE AREA AND THEN START TO BRING IN SOME SLIGHT CHANCES
FOR SNOW SUN AFTERNOON AND THEN START TO BRING IN SOME CHANCE POPS
FOR SUN NIGHT INTO MONDAY. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES. DID KEEP IN SOME RAIN/SNOW MIX FOR
MONDAY AFTERNOON.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW NEARING THE
UPPER GREAT LAKES 12Z TUE EMBEDDED IN A TROUGH OVER THE PLAINS
STATES. THE TROUGH AND UPPER LOW MOVE SLOWLY EAST 12Z WED AND ARE
EAST OF THE AREA INTO THE LOWER GREAT LAKES 12Z THU FOLLOWED BY
SHORTWAVE RIDGING OVER THE PLAINS. THIS RIDGING MOVES INTO THE UPPER
GREAT LAKES 12Z FRI. THIS SYSTEM FOR MONDAY NIGHT INTO THURSDAY IS
STILL NOT WELL HANDLED BY THE MODELS. THE ECMWF CONTINUES WITH A
FURTHER SOUTH TRACKING OF THE SFC LOW WHICH WOULD GIVE US COLDER AIR
AND MORE SNOW WHILE THE GFS TRACK IS FURTHER NORTH. THERE IS ALSO A
QUESTION OF IF THIS SYSTEM WILL GO FURTHER SOUTH AND EAST AND TURN
INTO AN EAST COAST STORM RATHER THAN A GREAT LAKES STORM. LOOKING AT
THE NEW ECMWF...IT CONTINUES TO GO WITH A GREAT LAKES SYSTEM...BUT
THE 500 MB TROUGH BECOMES VERY NEGATIVELY TILTED. HAVE A FEELING THE
FURTHER SOUTH AND EAST SOLUTION MAY VERIFY WITH THE EAST COAST STORM
THOUGH AND HOPEFULLY LATER MODEL RUNS WILL BE ABLE TO FIGURE THIS
OUT. WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO FOR NOW AS THE PCPN
TYPE AND SNOW AMOUNTS ARE HIGHLY DEPENDENT ON THE TRACK TO THE SFC
LOW AND THERE WILL BE SOME LAKE ENHANCEMENT TO THE SNOW AS WELL.
TEMPERATURES WILL BE ABOVE NORMAL FOR THIS FORECAST PERIOD. BUMPED
UP WINDS IN THE EXTENDED FROM 06Z THU ONWARD AS PRESSURE GRADIENT
TIGHTENS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1246 PM EST FRI DEC 19 2014

EXPECT LITTLE CHANGE THROUGH THE TAF PERIOD AS WARM AIR AND MOISTURE
ADVECTION CONTINUES BETWEEN A HIGH PRESSURE SYSTEM TO THE EAST AND A
TROUGH OVER THE NORTHERN PLAINS. MODELS ARE HAVING TROUBLE
REPRESENTING LOW LEVEL CLOUDS OVER KCMX AND KSAW. MODELS SHOW CLOUDS
MOVING NORTHEAST AND DIMINISHING...BUT CLOUDS HAVE BEEN STEADILY
EXPANDING THIS MORNING. FOR THIS REASON...THERE IS A GOOD AMOUNT OF
UNCERTAINTY WITH CIGS THROUGH THE TAF PERIOD. DO THINK THAT KSAW WILL
SCATTER OUT FOR A TIME THIS EVENING...WHICH MAY ALLOW FOG TO FORM AT
THE SITE. KCMX MAY CLEAR OUT THIS AFTERNOON/EVENING...BUT WAS LESS
CONFIDENT SO DID NOT INCLUDE THAT IN THE TAF.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 AM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HI PRES PASSING THRU
THE UPPER LAKES TODAY TO SHIFT TO THE S BUT REMAIN UNDER 20 KTS
UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25 KTS OVER
MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE OF AN
APPROACHING LO PRES. AS ANOTHER LO PRES DEVELOPS TO THE S...THE FLOW
WILL TEND TO BACK AND WEAKEN ON TUE. DEPENDING ON HOW QUICKLY THIS
SECOND LO DEVELOPS AND WHERE IT TRACKS...THERE COULD BE A NW GALE
EVENT ON WED OR XMAS DAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...07
AVIATION...TITUS
MARINE...KC







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 1249 PM EST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EST FRI DEC 19 2014

A FAIRLY QUIET PATTERN IN THE CENTRAL PART OF THE CONUS...AS THE
SOUTHERN STREAM JET IS SITUATED OVER THE SOUTHERN TIER OF STATES
AND THE SYSTEM THAT BROUGHT SNOW TO THE AREA THIS PAST
TUESDAY/WEDNESDAY IS NOW SPINNING OVER PRINCE EDWARD ISLAND. CLOSER
TO THIS AREA...AN UPPER RIDGE STRETCHES FROM WISCONSIN TO JAMES
BAY...WHILE A UPPER TROUGH IS LOCATED OVER SASKATCHEWAN AND THE
NORTHERN PLAINS. BENEATH THE UPPER RIDGE...1028MB HIGH PRESSURE IS
CENTERED OVER NORTHERN LAKE SUPERIOR WITH A RIDGE STRETCHING SOUTH
THROUGH THE MID MISSISSIPPI VALLEY. THERE IS PLENTY OF DRY AIR ALOFT
ON THE RAP ANALYSIS ASSOCIATED WITH THIS UPPER RIDGE...BUT THE
SUBSIDENCE HAS STRENGTHENED THE INVERSION OVER THE GREAT LAKES AND
UPPER MISSISSIPPI VALLEY REGIONS AND AIDED IN AREAS OF LOW CLOUDS.
THE LARGEST AREA OF LOW CLOUDS COVERS MUCH OF MINNESOTA AND WESTERN
WISCONSIN...WITH THE EASTERN EDGE STRETCHING FROM GRAND MARAIS
MINNESOTA THROUGH IRONWOOD MICHIGAN AND TOWARDS MADISON WISCONSIN.
BUT THERE IS A POCKET OF CLOUDS THAT DEVELOPED OVER SOUTH CENTRAL
LAKE SUPERIOR LATE THIS EVENING (AIDED BY MARGINAL DELTA-T VALUES
FOR LAKE CLOUDS) AND WITH THE LIGHT NORTHERLY FLOW...SHIFTED INTO
THE KEWEENAW AND NORTH CENTRAL U.P.  DEFINITELY HAVE TO GIVE SOME
CREDIT TO THE REGIONAL GEM...WHICH SUPERBLY PICKED UP ON THESE
CLOUDS WITH THE 00Z RUN YESTERDAY. THESE CLOUDS ALLOWED TEMPERATURES
TO QUICKLY RISE AROUND 10 DEGREES AND LOCATIONS UNDER THEM ARE IN
THE MID-UPPER TEENS. ELSEWHERE IN THE U.P. SKIES ARE CLEAR AND WITH
THE LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOWER SINGLE
DIGITS ABOVE AND BELOW ZERO.

THE UPPER RIDGE AND SURFACE HIGH CURRENTLY OVER THE AREA WILL
SLOWLY SHIFT EAST-SOUTHEAST TODAY AND TONIGHT...ALLOWING THE AREA
TO COME UNDER GREATER INFLUENCE OF THE WEAK UPPER TROUGH. THE LOW
CLOUDS WILL BE THE PRIMARY CONCERN FOR THE FORECAST FOR TODAY. WITH
GENERALLY LIGHT WINDS AND A RELATIVELY LOW SUN ANGLE...GETTING A
HANDLE ON THE LOW CLOUDS OVER THE NORTH CENTRAL AND KEWEENAW IS
DIFFICULT. FOLLOWING 925MB WINDS IN THE MODELS...WOULD EXPECT THEM
TO TRY TO NOSE A LITTLE FARTHER INLAND OVER THE CENTRAL (AND EVEN
THE EASTERN) PART OF THE U.P. TODAY...WHILE THE DEVELOPING LIGHT
SOUTHERLY FLOW WOULD LIKELY PULL DRIER AIR BACK INTO THE KEWEENAW
AND PUSH THOSE CLOUDS NORTH. BUT THAT INCREASING SOUTHERLY FLOW
WILL ALSO PULL THE CLOUDS RIGHT NEAR IRONWOOD INTO THE REST OF
GOGEBIC AND ONTONAGON COUNTIES THROUGH THE DAY TODAY...EVENTUALLY
REACHING IRON/HOUGHTON COUNTIES THIS EVENING AS THE LIMITED MIXING
DECREASES AND THE STRATUS CAN REALLY EXPAND. THESE LOW CLOUDS
(ALONG WITH MID CLOUDS FROM THE WEAK UPPER TROUGH AXIS SHIFTING EAST
INTO MINNESOTA) WILL CONTINUE TO SPREAD ACROSS UPPER MICHIGAN FROM
SOUTHWEST TO NORTHEAST TONIGHT AS SOUTHWESTERLY FLOW GRADUALLY
DEVELOPS.

AS FOR TEMPERATURES...EVEN WITH THE COLD START THIS MORNING IN
SOME LOCATIONS...EXPECT ANOTHER DAY OF HIGHS A LITTLE BIT
ABOVE NORMAL (UPPER 20S TO LOWER 30S). THE LOWS TONIGHT WILL BE
TRICKY...AS THEY DEPEND ON THE LOCATIONS OF THE CLOUD COVER. WHERE
SKIES ARE CLEAR OVER THE CENTRAL AND EAST...WOULD EXPECT ANOTHER
QUICK DROP TO TEMPS IN THE EVENING AND NEARING 0 UNDER LIGHT WINDS.
BUT WHERE THERE ARE CLOUDS...TEMPS WILL STRUGGLE TO FALL INTO THE
MID TEENS. WILL KEEP LOWS UP THE HIGHEST OVER THE FAR WEST...WHERE
THE CLOUDS WILL MOST LIKELY BE LOCATED.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM EST FRI DEC 19 2014

MAIN FCST CONCERNS IN THE MEDIUM/EXTENDED RANGE INCLUDE POPS ON SUN
NGT INTO MON AS A WAA REGIME DEVELOPS IN THE UPR LKS BTWN HI PRES
MOVING INTO NEW ENGLAND AND LO PRES TAKING SHAPE IN THE NRN PLAINS
ASSOCIATED WITH A STRONGER SHRTWV RIDING OVER A RDG ALONG THE W
COAST. THE POTENTIAL FOR A HEAVIER SYNOPTIC THEN LK ENHANCED SN IS
STILL THERE FOR TUE THRU XMAS AS THE DIGGING SHRTWV DEEPENS AN UPR
TROF OVER THE CENTRAL CONUS AND A LO PRES SOMEWHERE IN THE GREAT
LKS. BUT THERE REMAINS SOME INCONSISTENCIES AMONG THE MEDIUM/LONG
RANGE GUIDANCE ON THIS LO AND HOW QUICKLY A SECOND LO WL TAKE
SHAPE...SO CONFIDENCE IS LO ON THE FCST FOR MON THRU XMAS.

SAT/SAT NGT...A SFC HI PRES RDG STRETCHING FM WRN QUEBEC INTO THE
MID MS RIVER VALLEY ON SAT MRNG WILL MOVE SLOWLY TO THE E AND TO
NEAR NEW ENGLAND TO THE OH RIVER VALLEY BY 12Z SUN UNDER LGT W FLOW
ALOFT. A WEAK SHRTWV EMBEDDED IN THIS W FLOW WL BE DRIFTING THRU THE
UPR LKS DURING THIS PERIOD. ALTHOUGH THERE WL BE SOME WAA IN THE SW
FLOW ON THE BACK SIDE OF THE DEPARTING HI AND PVA IN ADVANCE OF THE
SHRTWV...MODELS SHOW ONLY WEAK ISENTROPIC ASCENT/DEEP LYR QVECTOR
CNVGC/UVV IN THE ABSENCE OF SGNFT MSTR INFLOW. SINCE FCST SDNGS
INDICATE LIMITED DEEP SATURATION...WL MAINTAIN GOING DRY FCST AND
MOCLDY SKIES. TEMPS SHOULD RUN ABOVE NORMAL FOR THE SEASON WITH H85
TEMPS NOT FAR FM -5C TO -7C.

SUN/SUN NGT...MOST OF THE MEDIUM RANGE OPERATIONAL MODELS SHOW
ANOTHER MORE COMPACT SHRTWV CROSSING THE UPR LKS ON LATE SUN INTO
EARLY MON ACCOMPANIED BY SOME SHARPER DPVA. IN TANDEM WITH SOME MORE
IMPRESSIVE ISENTROPIC ASCENT IN THE SSW FLOW BTWN THE DEPARTING HI
PRES RDG TO THE E AND FALLING MSLP IN THE NRN PLAINS ASSOCIATED WITH
A STRONGER SHRTWV RIDING THRU THE NRN ROCKIES AND OVER THE UPR RDG
OFF THE W COAST...MODELS DO GENERATE SOME WIDESPREAD ALBEIT LGT PCPN
AT TIMES DURING THIS PERIOD. THE GFS SHOWS A WEAKER SHRTWV/DYNAMIC
FORCING...BUT ENUF ISENTROPIC ASCENT TO GENERATE SOME LGT PCPN AS
WELL. FCST WL SHOW A PERIOD OF UP TO HI CHC POPS TO REFLECT MODEL
DISCREPANCIES ON THE TIMING OF THE STRONGER UVV. SSW FLOW UP THE
LENGTH OF LK MI MAY SUPPORT SOME HIER POPS OVER THE E...BUT MARGINAL
CHILL OF THE AIRMASS FOR LK ENHANCEMENT AND SOME SHEAR SHOULD LIMIT
THE POTENTIAL FOR A SGNFT IMPACT. TEMPS WL REMAIN ABOVE NORMAL...
ESPECIALLY ON SUN NGT WITH CLD COVER AND A STEADY S WIND GREATLY
LIMITING THE DIURNAL TEMP FALL.

MON THRU XMAS DAY...ALTHOUGH THE MEDIUM/LONG RANGE GUIDANCE ARE IN
AGREEMENT AN UPR TROF WL DEEPEN WITH AN H5 LO CLOSING OFF SOMEWHERE
OVER THE CENTRAL CONUS DOWNSTREAM OF THE RDG OVER THE FAR W AND THAT
THE CLOSED LO/UPR TROF WL TAKE ON A NEGATIVE TILT BY LATE TUE/XMAS
EVE...THERE ARE CONSIDERABLE DIFFERENCES ON THE FCST MSLP AND
THERMAL FIELDS. THE 12Z AND 00Z GFS ENSEMBLE SPREAD ON THE FCST LO
POSITION ON TUE/WED WAS QUITE WIDE...REFLECTING THE RATHER POOR
PREDICTABILITY OF THIS PATTERN WITH THE MAIN PLAYERS STILL OUT OVER
THE DATA POOR PACIFIC OCEAN. IN GENERAL...THE GFS IS FARTHER N WITH
THE RESULTING SFC LO AND THUS SHOWS WARMER LLVL TEMPS THAT WOULD BE
SUFFICIENT FOR A GOOD DEAL OF THE PCPN TO FALL AS RA OVER A GOOD
PORTION OF THE CWA. THE 00Z ECWMF ON THE OTHER HAND SHOWS A FARTHER
S TRACK FOR THE SFC LO AND QUICKER REDEVELOPMENT OF A DEEPER SECOND
LO ASSOCIATED WITH THE SHARPLY DIGGING SHRTWV INTO THE TROF THAT ALL
THE MODELS EVENTUALLY LATCH ON TO AS THE MAIN FEATURE. THE 00Z UKMET
IS CLOSER TO THE ECMWF...WHILE THE CNDN IS MORE OF A COMPROMISE.
SINCE BOTH THE GFS/ECWMF HAVE SHOWN CONTINUITY FM PREVIOUS RUNS AND
THERE IS CONSIDERABLE DIFFERENCES...FOLLOWED A MODEL CONSENSUS APRCH
FOR FCST PREPARATION. DID INCREASE POPS ABOVE THE CONSENSUS ON WED/
THU NEAR LK SUP WITH CYC NE UPSLOPE FLOW SHIFTING TO THE NW BY XMAS
TO THE NW OF DEEPENING LO AND DRAWING COLDER AIR INTO THE UPR LKS
THAT WOULD BE SUFFICIENT FOR SOME LK ENHANCEMENT /H85 TEMPS NEAR
-10C ON XMAS/.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1246 PM EST FRI DEC 19 2014

EXPECT LITTLE CHANGE THROUGH THE TAF PERIOD AS WARM AIR AND MOISTURE
ADVECTION CONTINUES BETWEEN A HIGH PRESSURE SYSTEM TO THE EAST AND A
TROUGH OVER THE NORTHERN PLAINS. MODELS ARE HAVING TROUBLE
REPRESENTING LOW LEVEL CLOUDS OVER KCMX AND KSAW. MODELS SHOW CLOUDS
MOVING NORTHEAST AND DIMINISHING...BUT CLOUDS HAVE BEEN STEADILY
EXPANDING THIS MORNING. FOR THIS REASON...THERE IS A GOOD AMOUNT OF
UNCERTAINTY WITH CIGS THROUGH THE TAF PERIOD. DO THINK THAT KSAW WILL
SCATTER OUT FOR A TIME THIS EVENING...WHICH MAY ALLOW FOG TO FORM AT
THE SITE. KCMX MAY CLEAR OUT THIS AFTERNOON/EVENING...BUT WAS LESS
CONFIDENT SO DID NOT INCLUDE THAT IN THE TAF.

&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 AM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HI PRES PASSING THRU
THE UPPER LAKES TODAY TO SHIFT TO THE S BUT REMAIN UNDER 20 KTS
UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25 KTS OVER
MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE OF AN
APPROACHING LO PRES. AS ANOTHER LO PRES DEVELOPS TO THE S...THE FLOW
WILL TEND TO BACK AND WEAKEN ON TUE. DEPENDING ON HOW QUICKLY THIS
SECOND LO DEVELOPS AND WHERE IT TRACKS...THERE COULD BE A NW GALE
EVENT ON WED OR XMAS DAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...KC
AVIATION...TITUS
MARINE...KC






AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 647 AM EST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EST FRI DEC 19 2014

A FAIRLY QUIET PATTERN IN THE CENTRAL PART OF THE CONUS...AS THE
SOUTHERN STREAM JET IS SITUATED OVER THE SOUTHERN TIER OF STATES
AND THE SYSTEM THAT BROUGHT SNOW TO THE AREA THIS PAST
TUESDAY/WEDNESDAY IS NOW SPINNING OVER PRINCE EDWARD ISLAND. CLOSER
TO THIS AREA...AN UPPER RIDGE STRETCHES FROM WISCONSIN TO JAMES
BAY...WHILE A UPPER TROUGH IS LOCATED OVER SASKATCHEWAN AND THE
NORTHERN PLAINS. BENEATH THE UPPER RIDGE...1028MB HIGH PRESSURE IS
CENTERED OVER NORTHERN LAKE SUPERIOR WITH A RIDGE STRETCHING SOUTH
THROUGH THE MID MISSISSIPPI VALLEY. THERE IS PLENTY OF DRY AIR ALOFT
ON THE RAP ANALYSIS ASSOCIATED WITH THIS UPPER RIDGE...BUT THE
SUBSIDENCE HAS STRENGTHENED THE INVERSION OVER THE GREAT LAKES AND
UPPER MISSISSIPPI VALLEY REGIONS AND AIDED IN AREAS OF LOW CLOUDS.
THE LARGEST AREA OF LOW CLOUDS COVERS MUCH OF MINNESOTA AND WESTERN
WISCONSIN...WITH THE EASTERN EDGE STRETCHING FROM GRAND MARAIS
MINNESOTA THROUGH IRONWOOD MICHIGAN AND TOWARDS MADISON WISCONSIN.
BUT THERE IS A POCKET OF CLOUDS THAT DEVELOPED OVER SOUTH CENTRAL
LAKE SUPERIOR LATE THIS EVENING (AIDED BY MARGINAL DELTA-T VALUES
FOR LAKE CLOUDS) AND WITH THE LIGHT NORTHERLY FLOW...SHIFTED INTO
THE KEWEENAW AND NORTH CENTRAL U.P.  DEFINITELY HAVE TO GIVE SOME
CREDIT TO THE REGIONAL GEM...WHICH SUPERBLY PICKED UP ON THESE
CLOUDS WITH THE 00Z RUN YESTERDAY. THESE CLOUDS ALLOWED TEMPERATURES
TO QUICKLY RISE AROUND 10 DEGREES AND LOCATIONS UNDER THEM ARE IN
THE MID-UPPER TEENS. ELSEWHERE IN THE U.P. SKIES ARE CLEAR AND WITH
THE LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOWER SINGLE
DIGITS ABOVE AND BELOW ZERO.

THE UPPER RIDGE AND SURFACE HIGH CURRENTLY OVER THE AREA WILL
SLOWLY SHIFT EAST-SOUTHEAST TODAY AND TONIGHT...ALLOWING THE AREA
TO COME UNDER GREATER INFLUENCE OF THE WEAK UPPER TROUGH. THE LOW
CLOUDS WILL BE THE PRIMARY CONCERN FOR THE FORECAST FOR TODAY. WITH
GENERALLY LIGHT WINDS AND A RELATIVELY LOW SUN ANGLE...GETTING A
HANDLE ON THE LOW CLOUDS OVER THE NORTH CENTRAL AND KEWEENAW IS
DIFFICULT. FOLLOWING 925MB WINDS IN THE MODELS...WOULD EXPECT THEM
TO TRY TO NOSE A LITTLE FARTHER INLAND OVER THE CENTRAL (AND EVEN
THE EASTERN) PART OF THE U.P. TODAY...WHILE THE DEVELOPING LIGHT
SOUTHERLY FLOW WOULD LIKELY PULL DRIER AIR BACK INTO THE KEWEENAW
AND PUSH THOSE CLOUDS NORTH. BUT THAT INCREASING SOUTHERLY FLOW
WILL ALSO PULL THE CLOUDS RIGHT NEAR IRONWOOD INTO THE REST OF
GOGEBIC AND ONTONAGON COUNTIES THROUGH THE DAY TODAY...EVENTUALLY
REACHING IRON/HOUGHTON COUNTIES THIS EVENING AS THE LIMITED MIXING
DECREASES AND THE STRATUS CAN REALLY EXPAND. THESE LOW CLOUDS
(ALONG WITH MID CLOUDS FROM THE WEAK UPPER TROUGH AXIS SHIFTING EAST
INTO MINNESOTA) WILL CONTINUE TO SPREAD ACROSS UPPER MICHIGAN FROM
SOUTHWEST TO NORTHEAST TONIGHT AS SOUTHWESTERLY FLOW GRADUALLY
DEVELOPS.

AS FOR TEMPERATURES...EVEN WITH THE COLD START THIS MORNING IN
SOME LOCATIONS...EXPECT ANOTHER DAY OF HIGHS A LITTLE BIT
ABOVE NORMAL (UPPER 20S TO LOWER 30S). THE LOWS TONIGHT WILL BE
TRICKY...AS THEY DEPEND ON THE LOCATIONS OF THE CLOUD COVER. WHERE
SKIES ARE CLEAR OVER THE CENTRAL AND EAST...WOULD EXPECT ANOTHER
QUICK DROP TO TEMPS IN THE EVENING AND NEARING 0 UNDER LIGHT WINDS.
BUT WHERE THERE ARE CLOUDS...TEMPS WILL STRUGGLE TO FALL INTO THE
MID TEENS. WILL KEEP LOWS UP THE HIGHEST OVER THE FAR WEST...WHERE
THE CLOUDS WILL MOST LIKELY BE LOCATED.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM EST FRI DEC 19 2014

MAIN FCST CONCERNS IN THE MEDIUM/EXTENDED RANGE INCLUDE POPS ON SUN
NGT INTO MON AS A WAA REGIME DEVELOPS IN THE UPR LKS BTWN HI PRES
MOVING INTO NEW ENGLAND AND LO PRES TAKING SHAPE IN THE NRN PLAINS
ASSOCIATED WITH A STRONGER SHRTWV RIDING OVER A RDG ALONG THE W
COAST. THE POTENTIAL FOR A HEAVIER SYNOPTIC THEN LK ENHANCED SN IS
STILL THERE FOR TUE THRU XMAS AS THE DIGGING SHRTWV DEEPENS AN UPR
TROF OVER THE CENTRAL CONUS AND A LO PRES SOMEWHERE IN THE GREAT
LKS. BUT THERE REMAINS SOME INCONSISTENCIES AMONG THE MEDIUM/LONG
RANGE GUIDANCE ON THIS LO AND HOW QUICKLY A SECOND LO WL TAKE
SHAPE...SO CONFIDENCE IS LO ON THE FCST FOR MON THRU XMAS.

SAT/SAT NGT...A SFC HI PRES RDG STRETCHING FM WRN QUEBEC INTO THE
MID MS RIVER VALLEY ON SAT MRNG WILL MOVE SLOWLY TO THE E AND TO
NEAR NEW ENGLAND TO THE OH RIVER VALLEY BY 12Z SUN UNDER LGT W FLOW
ALOFT. A WEAK SHRTWV EMBEDDED IN THIS W FLOW WL BE DRIFTING THRU THE
UPR LKS DURING THIS PERIOD. ALTHOUGH THERE WL BE SOME WAA IN THE SW
FLOW ON THE BACK SIDE OF THE DEPARTING HI AND PVA IN ADVANCE OF THE
SHRTWV...MODELS SHOW ONLY WEAK ISENTROPIC ASCENT/DEEP LYR QVECTOR
CNVGC/UVV IN THE ABSENCE OF SGNFT MSTR INFLOW. SINCE FCST SDNGS
INDICATE LIMITED DEEP SATURATION...WL MAINTAIN GOING DRY FCST AND
MOCLDY SKIES. TEMPS SHOULD RUN ABOVE NORMAL FOR THE SEASON WITH H85
TEMPS NOT FAR FM -5C TO -7C.

SUN/SUN NGT...MOST OF THE MEDIUM RANGE OPERATIONAL MODELS SHOW
ANOTHER MORE COMPACT SHRTWV CROSSING THE UPR LKS ON LATE SUN INTO
EARLY MON ACCOMPANIED BY SOME SHARPER DPVA. IN TANDEM WITH SOME MORE
IMPRESSIVE ISENTROPIC ASCENT IN THE SSW FLOW BTWN THE DEPARTING HI
PRES RDG TO THE E AND FALLING MSLP IN THE NRN PLAINS ASSOCIATED WITH
A STRONGER SHRTWV RIDING THRU THE NRN ROCKIES AND OVER THE UPR RDG
OFF THE W COAST...MODELS DO GENERATE SOME WIDESPREAD ALBEIT LGT PCPN
AT TIMES DURING THIS PERIOD. THE GFS SHOWS A WEAKER SHRTWV/DYNAMIC
FORCING...BUT ENUF ISENTROPIC ASCENT TO GENERATE SOME LGT PCPN AS
WELL. FCST WL SHOW A PERIOD OF UP TO HI CHC POPS TO REFLECT MODEL
DISCREPANCIES ON THE TIMING OF THE STRONGER UVV. SSW FLOW UP THE
LENGTH OF LK MI MAY SUPPORT SOME HIER POPS OVER THE E...BUT MARGINAL
CHILL OF THE AIRMASS FOR LK ENHANCEMENT AND SOME SHEAR SHOULD LIMIT
THE POTENTIAL FOR A SGNFT IMPACT. TEMPS WL REMAIN ABOVE NORMAL...
ESPECIALLY ON SUN NGT WITH CLD COVER AND A STEADY S WIND GREATLY
LIMITING THE DIURNAL TEMP FALL.

MON THRU XMAS DAY...ALTHOUGH THE MEDIUM/LONG RANGE GUIDANCE ARE IN
AGREEMENT AN UPR TROF WL DEEPEN WITH AN H5 LO CLOSING OFF SOMEWHERE
OVER THE CENTRAL CONUS DOWNSTREAM OF THE RDG OVER THE FAR W AND THAT
THE CLOSED LO/UPR TROF WL TAKE ON A NEGATIVE TILT BY LATE TUE/XMAS
EVE...THERE ARE CONSIDERABLE DIFFERENCES ON THE FCST MSLP AND
THERMAL FIELDS. THE 12Z AND 00Z GFS ENSEMBLE SPREAD ON THE FCST LO
POSITION ON TUE/WED WAS QUITE WIDE...REFLECTING THE RATHER POOR
PREDICTABILITY OF THIS PATTERN WITH THE MAIN PLAYERS STILL OUT OVER
THE DATA POOR PACIFIC OCEAN. IN GENERAL...THE GFS IS FARTHER N WITH
THE RESULTING SFC LO AND THUS SHOWS WARMER LLVL TEMPS THAT WOULD BE
SUFFICIENT FOR A GOOD DEAL OF THE PCPN TO FALL AS RA OVER A GOOD
PORTION OF THE CWA. THE 00Z ECWMF ON THE OTHER HAND SHOWS A FARTHER
S TRACK FOR THE SFC LO AND QUICKER REDEVELOPMENT OF A DEEPER SECOND
LO ASSOCIATED WITH THE SHARPLY DIGGING SHRTWV INTO THE TROF THAT ALL
THE MODELS EVENTUALLY LATCH ON TO AS THE MAIN FEATURE. THE 00Z UKMET
IS CLOSER TO THE ECMWF...WHILE THE CNDN IS MORE OF A COMPROMISE.
SINCE BOTH THE GFS/ECWMF HAVE SHOWN CONTINUITY FM PREVIOUS RUNS AND
THERE IS CONSIDERABLE DIFFERENCES...FOLLOWED A MODEL CONSENSUS APRCH
FOR FCST PREPARATION. DID INCREASE POPS ABOVE THE CONSENSUS ON WED/
THU NEAR LK SUP WITH CYC NE UPSLOPE FLOW SHIFTING TO THE NW BY XMAS
TO THE NW OF DEEPENING LO AND DRAWING COLDER AIR INTO THE UPR LKS
THAT WOULD BE SUFFICIENT FOR SOME LK ENHANCEMENT /H85 TEMPS NEAR
-10C ON XMAS/.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 646 AM EST FRI DEC 19 2014

TWO AREAS OF MVFR CEILINGS ARE AFFECTING THE TAF SITES THIS MORNING
AND WILL CONTINUE AT TIMES TODAY AND TONIGHT. AT KIWD...THE EDGE OF
LOW END MVFR CEILINGS HAS BEEN HOVERING OVER THE SITE DURING THE
OVERNIGHT HOURS. WITH LOW LEVEL WINDS STARTING TO INCREASE OUT
OF THE SOUTH...WOULD EXPECT THEM TO PUSH INTO THE SITE SHORTLY AND
CONTINUE THROUGH THE REST OF THE DAY AND INTO TONIGHT.

AT KCMX AND KSAW...MVFR STRATUS PUSHED INTO BOTH SITES LATE
YESTERDAY EVENING. WITH WINDS BECOMING LIGHT TODAY...CONFIDENCE IS
LOW ON THE TIMING OF THEM DEPARTING. THINK THEY WILL DEPART FIRST
AT KCMX WITH SOUTHERLY WINDS DEVELOPING EARLIER AND THERE HAVE BEEN
EASTERLY DOWNSLOPE WINDS OFF THE HURON MOUNTAINS LEADING TO SOME
CLEARING OVER THE KEWEENAW BAY. AT KSAW...THE NORTH-NORTHEASTERLY
FLOW WILL PERSIST THROUGH MUCH OF THE MORNING BEFORE BECOMING
VARIABLE. THAT SHOULD KEEP THE LOW CLOUDS IN THROUGH THE
MORNING...BUT THINK THE SHALLOW NATURE OF THE MOISTURE SHOULD ALLOW
THEM TO BREAK UP THIS AFTERNOON EVEN WITH THE LOW SUN ANGLE. ONCE
THE CLOUDS DEPART...EXPECT VFR CONDITIONS UNTIL THE MVFR CLOUDS
ARRIVE AGAIN FROM THE SOUTHWEST LATE THIS EVENING AND INTO THE
OVERNIGHT HOURS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 AM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HI PRES PASSING THRU
THE UPPER LAKES TODAY TO SHIFT TO THE S BUT REMAIN UNDER 20 KTS
UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25 KTS OVER
MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE OF AN
APPROACHING LO PRES. AS ANOTHER LO PRES DEVELOPS TO THE S...THE FLOW
WILL TEND TO BACK AND WEAKEN ON TUE. DEPENDING ON HOW QUICKLY THIS
SECOND LO DEVELOPS AND WHERE IT TRACKS...THERE COULD BE A NW GALE
EVENT ON WED OR XMAS DAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...KC
AVIATION...SRF
MARINE...KC






AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 347 AM EST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EST FRI DEC 19 2014

A FAIRLY QUIET PATTERN IN THE CENTRAL PART OF THE CONUS...AS THE
SOUTHERN STREAM JET IS SITUATED OVER THE SOUTHERN TIER OF STATES
AND THE SYSTEM THAT BROUGHT SNOW TO THE AREA THIS PAST
TUESDAY/WEDNESDAY IS NOW SPINNING OVER PRINCE EDWARD ISLAND. CLOSER
TO THIS AREA...AN UPPER RIDGE STRETCHES FROM WISCONSIN TO JAMES
BAY...WHILE A UPPER TROUGH IS LOCATED OVER SASKATCHEWAN AND THE
NORTHERN PLAINS. BENEATH THE UPPER RIDGE...1028MB HIGH PRESSURE IS
CENTERED OVER NORTHERN LAKE SUPERIOR WITH A RIDGE STRETCHING SOUTH
THROUGH THE MID MISSISSIPPI VALLEY. THERE IS PLENTY OF DRY AIR ALOFT
ON THE RAP ANALYSIS ASSOCIATED WITH THIS UPPER RIDGE...BUT THE
SUBSIDENCE HAS STRENGTHENED THE INVERSION OVER THE GREAT LAKES AND
UPPER MISSISSIPPI VALLEY REGIONS AND AIDED IN AREAS OF LOW CLOUDS.
THE LARGEST AREA OF LOW CLOUDS COVERS MUCH OF MINNESOTA AND WESTERN
WISCONSIN...WITH THE EASTERN EDGE STRETCHING FROM GRAND MARAIS
MINNESOTA THROUGH IRONWOOD MICHIGAN AND TOWARDS MADISON WISCONSIN.
BUT THERE IS A POCKET OF CLOUDS THAT DEVELOPED OVER SOUTH CENTRAL
LAKE SUPERIOR LATE THIS EVENING (AIDED BY MARGINAL DELTA-T VALUES
FOR LAKE CLOUDS) AND WITH THE LIGHT NORTHERLY FLOW...SHIFTED INTO
THE KEWEENAW AND NORTH CENTRAL U.P.  DEFINITELY HAVE TO GIVE SOME
CREDIT TO THE REGIONAL GEM...WHICH SUPERBLY PICKED UP ON THESE
CLOUDS WITH THE 00Z RUN YESTERDAY. THESE CLOUDS ALLOWED TEMPERATURES
TO QUICKLY RISE AROUND 10 DEGREES AND LOCATIONS UNDER THEM ARE IN
THE MID-UPPER TEENS. ELSEWHERE IN THE U.P. SKIES ARE CLEAR AND WITH
THE LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOWER SINGLE
DIGITS ABOVE AND BELOW ZERO.

THE UPPER RIDGE AND SURFACE HIGH CURRENTLY OVER THE AREA WILL
SLOWLY SHIFT EAST-SOUTHEAST TODAY AND TONIGHT...ALLOWING THE AREA
TO COME UNDER GREATER INFLUENCE OF THE WEAK UPPER TROUGH. THE LOW
CLOUDS WILL BE THE PRIMARY CONCERN FOR THE FORECAST FOR TODAY. WITH
GENERALLY LIGHT WINDS AND A RELATIVELY LOW SUN ANGLE...GETTING A
HANDLE ON THE LOW CLOUDS OVER THE NORTH CENTRAL AND KEWEENAW IS
DIFFICULT. FOLLOWING 925MB WINDS IN THE MODELS...WOULD EXPECT THEM
TO TRY TO NOSE A LITTLE FARTHER INLAND OVER THE CENTRAL (AND EVEN
THE EASTERN) PART OF THE U.P. TODAY...WHILE THE DEVELOPING LIGHT
SOUTHERLY FLOW WOULD LIKELY PULL DRIER AIR BACK INTO THE KEWEENAW
AND PUSH THOSE CLOUDS NORTH. BUT THAT INCREASING SOUTHERLY FLOW
WILL ALSO PULL THE CLOUDS RIGHT NEAR IRONWOOD INTO THE REST OF
GOGEBIC AND ONTONAGON COUNTIES THROUGH THE DAY TODAY...EVENTUALLY
REACHING IRON/HOUGHTON COUNTIES THIS EVENING AS THE LIMITED MIXING
DECREASES AND THE STRATUS CAN REALLY EXPAND. THESE LOW CLOUDS
(ALONG WITH MID CLOUDS FROM THE WEAK UPPER TROUGH AXIS SHIFTING EAST
INTO MINNESOTA) WILL CONTINUE TO SPREAD ACROSS UPPER MICHIGAN FROM
SOUTHWEST TO NORTHEAST TONIGHT AS SOUTHWESTERLY FLOW GRADUALLY
DEVELOPS.

AS FOR TEMPERATURES...EVEN WITH THE COLD START THIS MORNING IN
SOME LOCATIONS...EXPECT ANOTHER DAY OF HIGHS A LITTLE BIT
ABOVE NORMAL (UPPER 20S TO LOWER 30S). THE LOWS TONIGHT WILL BE
TRICKY...AS THEY DEPEND ON THE LOCATIONS OF THE CLOUD COVER. WHERE
SKIES ARE CLEAR OVER THE CENTRAL AND EAST...WOULD EXPECT ANOTHER
QUICK DROP TO TEMPS IN THE EVENING AND NEARING 0 UNDER LIGHT WINDS.
BUT WHERE THERE ARE CLOUDS...TEMPS WILL STRUGGLE TO FALL INTO THE
MID TEENS. WILL KEEP LOWS UP THE HIGHEST OVER THE FAR WEST...WHERE
THE CLOUDS WILL MOST LIKELY BE LOCATED.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM EST FRI DEC 19 2014

MAIN FCST CONCERNS IN THE MEDIUM/EXTENDED RANGE INCLUDE POPS ON SUN
NGT INTO MON AS A WAA REGIME DEVELOPS IN THE UPR LKS BTWN HI PRES
MOVING INTO NEW ENGLAND AND LO PRES TAKING SHAPE IN THE NRN PLAINS
ASSOCIATED WITH A STRONGER SHRTWV RIDING OVER A RDG ALONG THE W
COAST. THE POTENTIAL FOR A HEAVIER SYNOPTIC THEN LK ENHANCED SN IS
STILL THERE FOR TUE THRU XMAS AS THE DIGGING SHRTWV DEEPENS AN UPR
TROF OVER THE CENTRAL CONUS AND A LO PRES SOMEWHERE IN THE GREAT
LKS. BUT THERE REMAINS SOME INCONSISTENCIES AMONG THE MEDIUM/LONG
RANGE GUIDANCE ON THIS LO AND HOW QUICKLY A SECOND LO WL TAKE
SHAPE...SO CONFIDENCE IS LO ON THE FCST FOR MON THRU XMAS.

SAT/SAT NGT...A SFC HI PRES RDG STRETCHING FM WRN QUEBEC INTO THE
MID MS RIVER VALLEY ON SAT MRNG WILL MOVE SLOWLY TO THE E AND TO
NEAR NEW ENGLAND TO THE OH RIVER VALLEY BY 12Z SUN UNDER LGT W FLOW
ALOFT. A WEAK SHRTWV EMBEDDED IN THIS W FLOW WL BE DRIFTING THRU THE
UPR LKS DURING THIS PERIOD. ALTHOUGH THERE WL BE SOME WAA IN THE SW
FLOW ON THE BACK SIDE OF THE DEPARTING HI AND PVA IN ADVANCE OF THE
SHRTWV...MODELS SHOW ONLY WEAK ISENTROPIC ASCENT/DEEP LYR QVECTOR
CNVGC/UVV IN THE ABSENCE OF SGNFT MSTR INFLOW. SINCE FCST SDNGS
INDICATE LIMITED DEEP SATURATION...WL MAINTAIN GOING DRY FCST AND
MOCLDY SKIES. TEMPS SHOULD RUN ABOVE NORMAL FOR THE SEASON WITH H85
TEMPS NOT FAR FM -5C TO -7C.

SUN/SUN NGT...MOST OF THE MEDIUM RANGE OPERATIONAL MODELS SHOW
ANOTHER MORE COMPACT SHRTWV CROSSING THE UPR LKS ON LATE SUN INTO
EARLY MON ACCOMPANIED BY SOME SHARPER DPVA. IN TANDEM WITH SOME MORE
IMPRESSIVE ISENTROPIC ASCENT IN THE SSW FLOW BTWN THE DEPARTING HI
PRES RDG TO THE E AND FALLING MSLP IN THE NRN PLAINS ASSOCIATED WITH
A STRONGER SHRTWV RIDING THRU THE NRN ROCKIES AND OVER THE UPR RDG
OFF THE W COAST...MODELS DO GENERATE SOME WIDESPREAD ALBEIT LGT PCPN
AT TIMES DURING THIS PERIOD. THE GFS SHOWS A WEAKER SHRTWV/DYNAMIC
FORCING...BUT ENUF ISENTROPIC ASCENT TO GENERATE SOME LGT PCPN AS
WELL. FCST WL SHOW A PERIOD OF UP TO HI CHC POPS TO REFLECT MODEL
DISCREPANCIES ON THE TIMING OF THE STRONGER UVV. SSW FLOW UP THE
LENGTH OF LK MI MAY SUPPORT SOME HIER POPS OVER THE E...BUT MARGINAL
CHILL OF THE AIRMASS FOR LK ENHANCEMENT AND SOME SHEAR SHOULD LIMIT
THE POTENTIAL FOR A SGNFT IMPACT. TEMPS WL REMAIN ABOVE NORMAL...
ESPECIALLY ON SUN NGT WITH CLD COVER AND A STEADY S WIND GREATLY
LIMITING THE DIURNAL TEMP FALL.

MON THRU XMAS DAY...ALTHOUGH THE MEDIUM/LONG RANGE GUIDANCE ARE IN
AGREEMENT AN UPR TROF WL DEEPEN WITH AN H5 LO CLOSING OFF SOMEWHERE
OVER THE CENTRAL CONUS DOWNSTREAM OF THE RDG OVER THE FAR W AND THAT
THE CLOSED LO/UPR TROF WL TAKE ON A NEGATIVE TILT BY LATE TUE/XMAS
EVE...THERE ARE CONSIDERABLE DIFFERENCES ON THE FCST MSLP AND
THERMAL FIELDS. THE 12Z AND 00Z GFS ENSEMBLE SPREAD ON THE FCST LO
POSITION ON TUE/WED WAS QUITE WIDE...REFLECTING THE RATHER POOR
PREDICTABILITY OF THIS PATTERN WITH THE MAIN PLAYERS STILL OUT OVER
THE DATA POOR PACIFIC OCEAN. IN GENERAL...THE GFS IS FARTHER N WITH
THE RESULTING SFC LO AND THUS SHOWS WARMER LLVL TEMPS THAT WOULD BE
SUFFICIENT FOR A GOOD DEAL OF THE PCPN TO FALL AS RA OVER A GOOD
PORTION OF THE CWA. THE 00Z ECWMF ON THE OTHER HAND SHOWS A FARTHER
S TRACK FOR THE SFC LO AND QUICKER REDEVELOPMENT OF A DEEPER SECOND
LO ASSOCIATED WITH THE SHARPLY DIGGING SHRTWV INTO THE TROF THAT ALL
THE MODELS EVENTUALLY LATCH ON TO AS THE MAIN FEATURE. THE 00Z UKMET
IS CLOSER TO THE ECMWF...WHILE THE CNDN IS MORE OF A COMPROMISE.
SINCE BOTH THE GFS/ECWMF HAVE SHOWN CONTINUITY FM PREVIOUS RUNS AND
THERE IS CONSIDERABLE DIFFERENCES...FOLLOWED A MODEL CONSENSUS APRCH
FOR FCST PREPARATION. DID INCREASE POPS ABOVE THE CONSENSUS ON WED/
THU NEAR LK SUP WITH CYC NE UPSLOPE FLOW SHIFTING TO THE NW BY XMAS
TO THE NW OF DEEPENING LO AND DRAWING COLDER AIR INTO THE UPR LKS
THAT WOULD BE SUFFICIENT FOR SOME LK ENHANCEMENT /H85 TEMPS NEAR
-10C ON XMAS/.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1227 AM EST FRI DEC 19 2014

MVFR CLOUDS WHICH DEVELOPED AT THE TAF SITES LAST EVENING WILL
CONTINUE TO BE A FCST CONCERN OVER THE TAF PD. KIWD IS ON THE
EASTERN EDGE OF A MASS OF LOW CLOUDS OVER MN AND MUCH OF WESTERN
WI...AND GIVEN THAT THE PREVAILING WIND FLOW WILL CONTINUE TO PUSH
THE CLOUD DECK INTO THE AREA DO NOT SEE MUCH IMPROVEMENT OVER THE
NEXT 24 HOURS. MVFR LAKE CLOUDS HAVE DEVELOPED AT KSAW AND THESE
CLOUDS LIKELY WILL PUSH INTO KCMX OVERNIGHT AS WELL UNDER LIGHT ERLY
FLOW. LOOK FOR THIS CLOUD DECK TO LIFT AT BOTH KCMX AND KSAW LATE
THIS MORNING AS LIGHT WINDS TURN SE OR TO AN OFFSHORE/DOWNSLOPE
DIRECTION.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 AM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HI PRES PASSING THRU
THE UPPER LAKES TODAY TO SHIFT TO THE S BUT REMAIN UNDER 20 KTS
UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25 KTS OVER
MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE OF AN
APPROACHING LO PRES. AS ANOTHER LO PRES DEVELOPS TO THE S...THE FLOW
WILL TEND TO BACK AND WEAKEN ON TUE. DEPENDING ON HOW QUICKLY THIS
SECOND LO DEVELOPS AND WHERE IT TRACKS...THERE COULD BE A NW GALE
EVENT ON WED OR XMAS DAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...KC
AVIATION...VOSS
MARINE...KC




AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 1154 PM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.PREV DISCUSSION...ISSUED 746 PM EST THU DEC 18 2014

UPDATE...

RECENT RADAR SHOWING A DEFINITIVE UPTICK IN A DEFINED STRIPE OF
FREEZING DRIZZLE...PERHAPS ARGUABLY CLOSER TO FREEZING RAIN GIVEN
THE RETURNS...NOW SHIFTING THROUGH SOUTHERN LIVINGSTON/NORTHERN
WASHTENAW. THIS FEATURE REMAINS ANCHORED WITHIN A LINEAR AXIS OF
ENHANCED LOW LEVEL CONVERGENCE ACCOMPANYING THE PASSAGE OF A
SFC-850 MB TROUGH. 18Z NAM AND RECENT RAP GUIDANCE SUGGEST THIS
FEATURE WILL SLOWLY TRANSLATE SOUTHWARD OVER THE NEXT SEVERAL
HOURS...EFFECTIVELY SUSTAINING A FAVORABLE ENVIRONMENT FOR
MAINTENANCE OF THIS ONGOING LIGHT PRECIPITATION. POCKETS OF LIGHT
FREEZING DRIZZLE MIXED WITH SOME SNOWFLAKES WILL CONTINUE
ELSEWHERE SOUTH OF I-69 THROUGH ROUGHLY THE MIDNIGHT
WINDOW...THEREAFTER A LOSS OF MOISTURE DEPTH THROUGH THE BASE OF
THE INVERSION LAYER AS POST-TROUGH WINDS FLIP TO NORTHERLY SHOULD
BRING A NORTH TO SOUTH DIMINISHING TREND. THE GOING CONDITIONS IN
LIVINGSTON/WASHTENAW LIKELY CLOSING IN ON THE EDGE OF A VERY
SHORT FUSED ADVISORY HEADLINE. CALLS TO BOTH COUNTIES INDICATE
SLICK SPOTS ON SOME BRIDGES/OVERPASSES WITH ASSOCIATED SPINOUTS.
THIS BAND DOES APPEAR TRANSIENT ENOUGH AND OF SHORT ENOUGH
DURATION AT THIS TIME TO HOLD TIGHT IN HANDLING THE SITUATION
WITH SPECIAL WEATHER STATEMENTS /SPSDTX/...BUT WILL CONTINUE TO
MONITOR.

PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).



AREA FORECAST DISCUSSION

NWS JACKSON MS

 1037 AM CST FRI DEC 19 2014

.UPDATE...

THE FORECAST IS GENERALLY ON TRACK FOR TODAY WITH WIDESPREAD LIGHT TO
MODERATE RAINFALL SPREADING EAST-NORTHEAST ACROSS MOST OF THE
ARKLAMISS. THE GREATEST MOISTURE FLUX/ASCENT HAS BEEN FOCUSING A BAND
OF HEAVIER RAIN OVER CENTRAL LA THAT SHOULD AFFECT THE I-20 CORRIDOR
THROUGH MID AFTERNOON. THEREAFTER...CONVECTIVE RAINFALL CURRENTLY
OVER SE TX/SW LA IS FORECAST BY THE HRRR TO ACCELERATE EASTWARD
ALONG THE COAST AND INTERCEPT BETTER MOISTURE FLUX. GUIDANCE
SUGGESTS THIS WILL HELP TO FOCUS BETTER LIFT AND HEAVIER RAINFALL
OVER SOUTHERN PORTIONS OF THE FORECAST AREA AS WE GO INTO THE
EVENING.

OVERALL...RAINFALL AMOUNTS OF 1-2 INCHES ALONG AND SOUTH OF I-20
STILL LOOK LIKE A REASONABLE FORECAST. OTHERWISE WILL BE MAKING SOME
MINOR ADJUSTMENTS TO TEMPERATURES TO ACCOUNT FOR LATEST TRENDS. /EC/

&&

.AVIATION...

DETERIORATING CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON
AS A LOW PRESSURE SYSTEM MOVES ALONG THE GULF COAST AND SENDS
WIDESPREAD RAIN INLAND. MVFR CEILINGS SHOULD BE COMMON TODAY INTO
THIS EVENING WITH SOME MVFR VIS RESTRICTIONS. IN ADDITION THERE WILL
BE SOME OCCASIONAL IFR RESTRICTIONS... PARTICULARLY ALONG AND SOUTH
OF THE HKS/JAN TO MEI CORRIDOR WHERE THE HEAVIER RAINFALL IS
EXPECTED. /28/17/

&&

.PREV DISCUSSION... /ISSUED 345 AM CST FRI DEC 19 2014/

SHORT TERM...TODAY THROUGH SATURDAY NIGHT...AREA RADARS AND
SATELLITE ARE PICKING UP LIGHT TO MODERATE RAIN WITH SOME EMBEDDED
CONVECTION OVER SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA PUSHING
TOWARD THE ARKLAMISS...ASSOCIATED WITH A STRONG SHORTWAVE TROUGH WAS
OBSERVED OVER THE SOUTHERN PLAINS. HIGH RES MODELS SHOW WIDESPREAD
MODERATE RAINS PUSHING INTO THE REGION FOR TODAY THROUGH TONIGHT.
MODEL CROSS SECTIONS AND SOUNDINGS CONTINUE TO SUPPORT SOME EMBEDDED
CONVECTION ACROSS THE SOUTH FOR TODAY. MODELS CONTINUE TO SUPPORT
STRONG ISENTROPIC ASCENT FOR POTENTIALLY HEAVY RAINFALL RATES...BUT
GUIDANCE HAS GENERALLY COME DOWN TO MAINLY ONE TO TWO INCHES SOUTH OF
INTERSTATE 20 WITH LIGHTER AMOUNTS FARTHER NORTH. SO WITH THIS IN
MIND WILL KEEP CURRENT WIDESPREAD POPS FOR TODAY AND LOWER POPS SOME
FOR TONIGHT. THE RAINS WILL MOVE OUT OF THE REGION ON SATURDAY
MORNING. ANOTHER SHORTWAVE WILL COME DOWN INTO THE SOUTHERN PLAINS ON
SUNDAY. IT WILL PUSH MOISTURE TOWARD THE REGION FROM THE SOUTH ON
LATE SUNDAY NIGHT AS CLOUDS INCREASE ACROSS THE REGION./17/

LONG TERM...SUNDAY THROUGH FRIDAY...SUNDAY MORNING A SURFACE RIDGE
AXIS FROM THE NORTHEAST WILL BE ACROSS THE NORTHERN PORTIONS OF OUR
CWA AND LIMIT ANY LOW LEVEL MOISTURE RETURN AHEAD OF THE NEXT UPPER
LEVEL TROUGH THAT WILL BE OVER THE CENTRAL CONUS. A WEAK SURFACE LOW
WILL DEVELOP OVER THE WESTERN GULF IN RESPONSE TO THE APPROACHING
TROUGH AND RESULT IN RAIN CHANCES OVER OUR SOUTHEAST ZONES SUNDAY
AFTERNOON. THIS SURFACE LOW WILL TRACK FARTHER SOUTH THAN THE ONE ON
FRIDAY. MODELS SHOW BY SUNDAY AFTERNOON THE RIGHT REAR QUAD OF A
>120KT JET STREAK OVER OUR SOUTHEAST COUNTIES BUT PWS WILL ONLY BE
ONE INCH OR LESS AND INSTABILITY WILL BE LIMITED SO ONLY LOW POPS OF
LIGHT QPF IS EXPECTED. THIS SYSTEM WILL SHIFT EAST OF OUR CWA BY
MONDAY MORNING BUT A CLOSED LOW WILL DROP OVER THE NORTHERN PLAINS
MONDAY RESULTING IN A DEEPENING OF THE UPPER LEVEL TROUGH OVER THE
CENTRAL CONUS. THIS WILL INDUCE WEAK WAA ADVECTION OVER OUR REGION
DURING THE DAY MONDAY AND RESULT IN A FEW LIGHT SHOWERS. THE
DEEPENING TROUGH WILL SUPPORT A STRONG COLD FRONT THAT IS EXPECTED
TO MOVE ACROSS OUR CWA TUESDAY. THE CHANCE FOR RAIN WILL INCREASE
AFTER MIDNIGHT MONDAY NIGHT AND THE HIGHEST POPS OF THE LONG TERM
WILL BE CARRIED ACROSS THE AREA ALONG AND AHEAD OF THE FRONT
TUESDAY. COOLER AND DRIER AIR WILL FILTER INTO THE REGION TUESDAY
NIGHT SENDING TEMPERATURES BELOW NORMAL BY WEDNESDAY MORNING. THE
GFS IS MUCH FARTHER NORTH THAN THE ECMWF WITH THE CLOSED LOW
WEDNESDAY MORNING AND ENDS THE RAIN FASTER. RAIN WILL LIKELY LINGER
LONGER INTO TUESDAY NIGHT THAN WAS THOUGH LAST NIGHT BUT DRY WEATHER
IS EXPECTED TO RETURN WEDNESDAY. THE CLOSED LOW WILL LIFT UP INTO
CANADA WEDNESDAY NIGHT AND THE UPPER TROUGH WILL SHIFT EAST OF OUR
CWA. THIS WILL LEAVE NEAR ZONAL FLOW ACROSS OUR CWA AND A WEAK
SURFACE LOW OVER THE NORTHERN GULF FOR CHRISTMAS DAY. CHRISTMAS DAY
WILL BE DRY BUT THE GFS AND ECMWF DIFFER SIGNIFICANTLY WITH THE NEXT
UPPER LEVEL TROUGH MOVING OVER THE ROCKIES. THE ECMWF IS MUCH
STRONGER WITH A CLOSED LOW AND ASSOCIATED SURFACE LOW OVER THE
CENTRAL CONUS BY FRIDAY MORNING. EITHER SOLUTION WILL BRING AN
INCREASE IN RAIN CHANCES DURING THE DAY FRIDAY. /22/

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.

&&

$$







AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 924 PM CST Sat Dec 20 2014

.UPDATE:
Issued at 924 PM CST Sat Dec 20 2014

Clouds are lingering over the entire CWA this evening and will
likely do so into the overnight hours as we are experiencing one
of the longest nights of the year. Latest satellite observations
has shown that low clouds are expanding slowly  eastward over
east central/southeast Illinois while there has been very little
movement over southeast Missouri. Latest ACARS sounding from KSTL
shows a decent inversion between 900-850mb with plenty of moisture
below it, and the RAP keeps plenty of low level moisture over the
CWA tonight, so left cloudy skies over the CWA the rest of the
night. Also raised temperatures tonight, particularly in the
southern and eastern counties where clearing was previously
forecast.

Britt

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 302 PM CST Sat Dec 20 2014

Clouds will persist early tonight and perhaps start to decrease
from south to north by morning. Overnight lows should be similar
to last night in most locations.

Kanofsky

.LONG TERM:  (Sunday through Next Saturday)
Issued at 302 PM CST Sat Dec 20 2014

The primary forecast issues revolve around a large low pressure
system and a deep trough which are expected to affect the area
between Mon and Wed.

The ongoing gradual warming trend (highs today were generally about
5 degrees warmer than yesterday, which in turn was a few degrees
warmer than the previous day) will persist on Sunday and Monday.
Monday`s highs in the mid-40s to lower 50s will be around 10
degrees above average for this time of year.

The aforementioned low pressure system develops over the northern
plains on Sunday and Sunday night, eventually closing off on Mon or
Mon night within a deep trough over the central CONUS. This system
will dominate our weather through Wed, and widespread rain is likely
as it moves into the region on Mon and Mon night. Forecast PW values
of between 0.6" and 0.8" by 00z Tue are above the 75th percentile
and approaching +2 SD for December. A cold front is expected to move
through parts of MO/IL on late Mon night or Tue morning, which is
slower timing than the models were predicting yesterday. By Tue
afternoon or evening, some of the rain will probably switch over
to light snow within the colder post-frontal air mass.
Temperatures return to near or below average behind the front.

Meanwhile, a second vort max is forecast to drop into the central
CONUS trough and induce a new surface wave along the cold front
somewhere in TX/AR/LA (a third, smaller vort max interacts with
the northern upper low center during this time). The resulting
southern system then lifts northeastward on Tue and Tue night, but
there are sufficient differences between the GFS and ECMWF to
preclude getting more specific than SChc/Chc PoPs with a generic
rain/snow mix.

After the trough rotates away on Wed night or Thu, a brief period
of upper ridging is anticipated ahead of the next disturbance. The
12z runs of the ECMWF and GFS are in better agreement on the large
scale pattern compared to 24hrs ago, but the forecast with this
system will still depend on what will have happened with the
previous system, and confidence remains low.

Kanofsky

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 506 PM CST Sat Dec 20 2014

Focus will be cigs thru the period. Overall, guidance does not
have a good handle on the current trends across the region.
Therefore, have lower confidence in cig heights, but believe
overall trend is well reflected in TAFs. Believe conditions will
remain largely as-is except for CPS becoming MVFR in the next hour
or so. Guidance suggests that cigs at UIN/COU may also drop to IFR
late tonight into Sun morning. However, confidence is too low to
mention in TAF attm. Otherwise, cigs shud slowly lift Sun around
Noon or during the afternoon.

Specifics for KSTL: Expect cigs to remain in higher MVFR range
thru much of the forecast period with sely to ssely winds aob 10
kts. Believe cigs will lift to VFR Sun afternoon, however, exact
timing is uncertain.

Tilly

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 1203 PM CST Fri Dec 19 2014

.UPDATE:
Issued at 1155 AM CST Fri Dec 19 2014

A few tweaks to going forecast...primarily to adjust chaotic cloud
cover over our IL counties and to raise temps there a degree or
two due to a bit more sun. Other change has been to pull mention
of drizzle over mid MO for this afternoon as stratus has
temporarily lifted here. However, did continue mention of flurries
over our se MO counties as very light echoes on n fringes of s
system showing up over nw AR, and heading to the NE.

Truett

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 300 AM CST Fri Dec 19 2014

A weak ridge of high pressure which extends from the Great Lakes
region south through the Mid-Mississippi Valley is in control of our
weather today.  Soundings are showing plenty of low level moisture
trapped under an inversion at around 850mb.  The vertical structure
of the atmosphere is much like what we had last weekend with the
moisture stratified in the low levels, so I don`t expect much
sunshine for the majority of the area...with the possible exception
of south central and extreme southwest Illinois.  Some drier air is
trying to drift in on weak easterly low level flow.  Vertical cross
sections show intermittent weak upward motion through the day,
primarily over central Missouri, and short term guidance spits out a
hundredth of QPF here and there.  Additionally, the HRRR shows some
weak simulated radar echos over parts of central and southeast
Missouri today, so have added in a little patchy drizzle to the
forecast.

Carney

.LONG TERM:  (Tonight through Thursday)
Issued at 300 AM CST Fri Dec 19 2014

(Tonight - Saturday)

The brunt of a storm system is expected to pass relatively unnoticed
to our south this evening, and if it weren`t for some interaction
with a more northerly component, would probably result in no
precipitation anywhere, but such as it is, some very light snow
looks to be possible early this evening for an area primarily south
of STL metro.  This arrangement should be short-lived, with much of
the mid and upper level moisture quickly being shunted off to the
east, leaving behind extensive low cloud cover.  At this point,
there is good model consensus on a weak WAA, convergence regime
setting up at the low levels that noses into central MO by midnight
tonight and then snaking its way northward towards the UIN area by
Saturday morning.  Have added in patchy drizzle as a result.  For
now, expecting influence of the surface RIDGE to trump this for STL
metro and areas S and E.  Temps will probably not go very far
tonight with clouds hanging tough, although where the surface RIDGE
is dominant, should see a steady but slow drop...but for areas to
the N and W of STL metro where a light S flow will persist, near
steady temps are expected.  Speaking of temps, especially to the N
and W of STL metro where drizzle is expected to develop, readings
will be within a degree or two of the freezing mark and so this will
probably manifest more as patchy FZDZ for areas in northeast MO and
west-central IL.  Prefer the lower MOS temps for Saturday maxes
given cloud cover expected, but they should still rebound into the
upper 30s and low 40s.

(Sunday - Wednesday)

A rather deep upper level TROF is expected to develop later on
Sunday over the central CONUS and then take a good part of the week
before finally shifting east.  Maintained the highest PoPs for
Monday thru Tuesday, where there is good model consensus on when the
TROF will be close enough, yet its axis still just upstream...and
then reduce to slight chances by Wednesday when the TROF axis by
this time will have shifted to the east.

While much of the precipitation will be just rain, especially on the
front-end, enough cold air starts working in on Tuesday, especially
aloft, that will allow the atmosphere to sustain a changeover to
snow.  The only limiting factor at this point will be surface and/or
boundary layer temps that will ultimately determine the rain vs.
snow question.  GFS and EC MOS surface temps suggest this will not
happen for most locales until late in the day on Tuesday with snow
then expected as the dominant p-type from that point on.  This will
also be when the upper TROF axis will be crossing thru, and so what
is left will probably not be much, but perhaps light snow accums
will be possible Tuesday night and early Wednesday.  This will be
our only realistic chance at a white Christmas, and something to
watch, as a deeper system that digs a bit more south would up the
potential.

(Christmas)

Models have been advertising for several days now a transitional
period this day which should give us a net result of quiet wx with
near seasonal temps.  Nothing has changed with the current model
runs so will let it stand.

TES

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1155 AM CST Fri Dec 19 2014

Pocket of low level dry air on the IL side of the Mississippi
River continue to make for tricky aviation forecasts. Will
primarily go with MVFR cigs from 1.5-3kft this afternoon, although
its possible that sites along the river (KUIN and STL metro TAFs)
may be on the fringes of this cloud deck. Wedge of dry air is
forecast to hold firm tonight, and while it appears likely that
IFR fog and stratus will once again form over COU in the deeper
low level moisture, trend is less clear cut for sites along the
river. It`s interesting that most guidance isn`t as bullish as
yesterday with IFR development at UIN and STL metro, in spite of
the fact that low level flow does become a bit more southerly
during the predawn hours (albeit weakly so). So, for these
locations have headed towards lower end MVFR cigs/vsbys during the
predawn hours, with the expectation that the primary IFR deck will
remain just west of the MSRVR.

Specifics for KSTL: As mentioned above, area will be on the
western fringes of a pocket of drier low level air over IL. Have
generally gone with bkn MVFR cloud deck through 06z to try to
reflect this, but a slight shift in the edge of this moisture
could mean more or less cloudiness in the MVFR range. Forecast
hints at some lower vsbys and cloudiness during the predawn hours,
but based on the preponderence of guidance have maintained
prevailing ceiling and vsbys in the MVFR range.

Truett

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 551 AM CST Fri Dec 19 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 300 AM CST Fri Dec 19 2014

A weak ridge of high pressure which extends from the Great Lakes
region south through the Mid-Mississippi Valley is in control of our
weather today.  Soundings are showing plenty of low level moisture
trapped under an inversion at around 850mb.  The vertical structure
of the atmosphere is much like what we had last weekend with the
moisture stratified in the low levels, so I don`t expect much
sunshine for the majority of the area...with the possible exception
of south central and extreme southwest Illinois.  Some drier air is
trying to drift in on weak easterly low level flow.  Vertical cross
sections show intermittent weak upward motion through the day,
primarily over central Missouri, and short term guidance spits out a
hundredth of QPF here and there.  Additionally, the HRRR shows some
weak simulated radar echos over parts of central and southeast
Missouri today, so have added in a little patchy drizzle to the
forecast.

Carney

.LONG TERM:  (Tonight through Thursday)
Issued at 300 AM CST Fri Dec 19 2014

(Tonight - Saturday)

The brunt of a storm system is expected to pass relatively unnoticed
to our south this evening, and if it weren`t for some interaction
with a more northerly component, would probably result in no
precipitation anywhere, but such as it is, some very light snow
looks to be possible early this evening for an area primarily south
of STL metro.  This arrangement should be short-lived, with much of
the mid and upper level moisture quickly being shunted off to the
east, leaving behind extensive low cloud cover.  At this point,
there is good model consensus on a weak WAA, convergence regime
setting up at the low levels that noses into central MO by midnight
tonight and then snaking its way northward towards the UIN area by
Saturday morning.  Have added in patchy drizzle as a result.  For
now, expecting influence of the surface RIDGE to trump this for STL
metro and areas S and E.  Temps will probably not go very far
tonight with clouds hanging tough, although where the surface RIDGE
is dominant, should see a steady but slow drop...but for areas to
the N and W of STL metro where a light S flow will persist, near
steady temps are expected.  Speaking of temps, especially to the N
and W of STL metro where drizzle is expected to develop, readings
will be within a degree or two of the freezing mark and so this will
probably manifest more as patchy FZDZ for areas in northeast MO and
west-central IL.  Prefer the lower MOS temps for Saturday maxes
given cloud cover expected, but they should still rebound into the
upper 30s and low 40s.

(Sunday - Wednesday)

A rather deep upper level TROF is expected to develop later on
Sunday over the central CONUS and then take a good part of the week
before finally shifting east.  Maintained the highest PoPs for
Monday thru Tuesday, where there is good model consensus on when the
TROF will be close enough, yet its axis still just upstream...and
then reduce to slight chances by Wednesday when the TROF axis by
this time will have shifted to the east.

While much of the precipitation will be just rain, especially on the
front-end, enough cold air starts working in on Tuesday, especially
aloft, that will allow the atmosphere to sustain a changeover to
snow.  The only limiting factor at this point will be surface and/or
boundary layer temps that will ultimately determine the rain vs.
snow question.  GFS and EC MOS surface temps suggest this will not
happen for most locales until late in the day on Tuesday with snow
then expected as the dominant p-type from that point on.  This will
also be when the upper TROF axis will be crossing thru, and so what
is left will probably not be much, but perhaps light snow accums
will be possible Tuesday night and early Wednesday.  This will be
our only realistic chance at a white Christmas, and something to
watch, as a deeper system that digs a bit more south would up the
potential.

(Christmas)

Models have been advertising for several days now a transitional
period this day which should give us a net result of quiet wx with
near seasonal temps.  Nothing has changed with the current model
runs so will let it stand.

TES

&&

.AVIATION:  (For the 12z TAFs through 12z Saturday Morning)
Issued at 538 AM CST Fri Dec 19 2014

Expect persistent ceilings across the area today decreasing from
VFR over Illinois to MVFR in eastern Missouri and down to IFR in
central and parts of southeast Missouri. Patchy drizzle is also
possible across the region today, particularly in central
Missouri. Ceilings will likely drop slowly overnight tonight, with
more patchy drizzle over parts of the area.

Specifics for KSTL:

Ceilings will likely stay in MVFR range today. Short-range
guidance is indicating that there will be a period of ceilings
below 2000ft for this morning, and this seems reasonable given
weak low level flow from the northeast and a few obs with ceilings
around 1000ft upstream. Could see a little drizzle in the area
today, but greater chances for drizzle should be over central
Missouri. Expect that MVFR ceilings will continue through tonight.

Carney

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     35  31  41  34 /  10  10  10   5
Quincy          32  29  38  31 /  10  10  10  10
Columbia        35  33  41  34 /  10  10  10   5
Jefferson City  37  34  42  34 /  10  10  10   5
Salem           35  29  41  31 /  10  10   5   0
Farmington      36  30  43  31 /  10  10  10   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






AREA FORECAST DISCUSSION

NWS ST LOUIS MO

 300 AM CST Fri Dec 19 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 300 AM CST Fri Dec 19 2014

A weak ridge of high pressure which extends from the Great Lakes
region south through the Mid-Mississippi Valley is in control of our
weather today.  Soundings are showing plenty of low level moisture
trapped under an inversion at around 850mb.  The vertical structure
of the atmosphere is much like what we had last weekend with the
moisture stratified in the low levels, so I don`t expect much
sunshine for the majority of the area...with the possible exception
of south central and extreme southwest Illinois.  Some drier air is
trying to drift in on weak easterly low level flow.  Vertical cross
sections show intermittent weak upward motion through the day,
primarily over central Missouri, and short term guidance spits out a
hundredth of QPF here and there.  Additionally, the HRRR shows some
weak simulated radar echos over parts of central and southeast
Missouri today, so have added in a little patchy drizzle to the
forecast.

Carney

.LONG TERM:  (Tonight through Thursday)
Issued at 300 AM CST Fri Dec 19 2014

(Tonight - Saturday)

The brunt of a storm system is expected to pass relatively unnoticed
to our south this evening, and if it weren`t for some interaction
with a more northerly component, would probably result in no
precipitation anywhere, but such as it is, some very light snow
looks to be possible early this evening for an area primarily south
of STL metro.  This arrangement should be short-lived, with much of
the mid and upper level moisture quickly being shunted off to the
east, leaving behind extensive low cloud cover.  At this point,
there is good model consensus on a weak WAA, convergence regime
setting up at the low levels that noses into central MO by midnight
tonight and then snaking its way northward towards the UIN area by
Saturday morning.  Have added in patchy drizzle as a result.  For
now, expecting influence of the surface RIDGE to trump this for STL
metro and areas S and E.  Temps will probably not go very far
tonight with clouds hanging tough, although where the surface RIDGE
is dominant, should see a steady but slow drop...but for areas to
the N and W of STL metro where a light S flow will persist, near
steady temps are expected.  Speaking of temps, especially to the N
and W of STL metro where drizzle is expected to develop, readings
will be within a degree or two of the freezing mark and so this will
probably manifest more as patchy FZDZ for areas in northeast MO and
west-central IL.  Prefer the lower MOS temps for Saturday maxes
given cloud cover expected, but they should still rebound into the
upper 30s and low 40s.

(Sunday - Wednesday)

A rather deep upper level TROF is expected to develop later on
Sunday over the central CONUS and then take a good part of the week
before finally shifting east.  Maintained the highest PoPs for
Monday thru Tuesday, where there is good model consensus on when the
TROF will be close enough, yet its axis still just upstream...and
then reduce to slight chances by Wednesday when the TROF axis by
this time will have shifted to the east.

While much of the precipitation will be just rain, especially on the
front-end, enough cold air starts working in on Tuesday, especially
aloft, that will allow the atmosphere to sustain a changeover to
snow.  The only limiting factor at this point will be surface and/or
boundary layer temps that will ultimately determine the rain vs.
snow question.  GFS and EC MOS surface temps suggest this will not
happen for most locales until late in the day on Tuesday with snow
then expected as the dominant p-type from that point on.  This will
also be when the upper TROF axis will be crossing thru, and so what
is left will probably not be much, but perhaps light snow accums
will be possible Tuesday night and early Wednesday.  This will be
our only realistic chance at a white Christmas, and something to
watch, as a deeper system that digs a bit more south would up the
potential.

(Christmas)

Models have been advertising for several days now a transitional
period this day which should give us a net result of quiet wx with
near seasonal temps.  Nothing has changed with the current model
runs so will let it stand.

TES

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1142 PM CST Thu Dec 18 2014

Extensive area of IFR conditions currently cover most of central
Missouri reach to just west of the St. Louis metro area and just
southwest of KUIN.  Expect KCOU to remain IFR until mid afternoon
on Friday. Expect that ceilings and visibilities will slowly fall
at KUIN and the St. Louis metro TAF sites the remainder of the
night, and then slowly improve back to MVFR by late morning or
early afternoon on Friday. Winds will remain light through the
period.

Specifics for KSTL:  Expect current ceilings to fall below 2000 ft
in the next hour or two as large area of IFR conditions just west
of the terminal moves east. Then ceilings and visibilities will
likely slowly decrease through the night given the high atmospheric
moisture and light winds. LIFR conditions are still expected
between 10-17Z. Do expect some slow improvement in ceilings and
visibilities during the afternoon hours, with ceilings increasing
above 2000 feet after 22Z.

Britt

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     35  31  41  34 /  10  10  10   5
Quincy          32  29  38  31 /  10  10  10  10
Columbia        35  33  41  34 /  10  10  10   5
Jefferson City  37  34  42  34 /  10  10  10   5
Salem           35  29  41  31 /  10  10   5   0
Farmington      36  30  43  31 /  10  10  10   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





AREA FORECAST DISCUSSION

NWS GREAT FALLS MT

 900 PM MST Sat Dec 20 2014

.DISCUSSION...
Update forthcoming. Have lowered temperatures a tad in areas where
advancing clouds have yet to arrive. With clouds overspreading the
area from the west overnight, temperatures will not drop too far.
High wind highlights will remain in place, though wind speeds are
currently below warning criteria along the Rocky Mountain Front.
Latest RUC analysis indicates westerly winds aloft will strengthen
considerably after 10z. Winter Weather Advisory highlights will also
continue. Snow has begun over the Rocky Mountain Front and over
portions of southwest Montana. Snow not expected to begin over the
Central mountains until after midnight, closer to daybreak.

&&

.AVIATION...
UPDATED 2335Z.
A strengthening and increasingly moist West/Northwest flow aloft
will move across the Northern Rockies and MT tonight through Sunday.
This will spread increasing cloudiness across the region tonight
with precipitation and terrain obscurations increasing over the
mountains tonight and continuing through Sunday. Precipitation will
spread into the KBZN terminal vicinity after 06z with occasional
MVFR in lower CIGS/-SN late tonight through Sunday morning before
conditions improve some Sunday afternoon. Precipitation will be less
widespread at lower elevations of Central/N-Central MT. W-NW winds
aloft increase to around 50kts at ridgetops Sunday with Mtn wave
turbulence likely east of the Rockies and gusty surface winds likely
at most terminals. Hoenisch

&&

.PREV DISCUSSION...Issued 303 PM MST Sat Dec 20 2014

Tonight through Monday...A plume of moisture is pushing through
the Pacific Northwest on a strong westerly jetstream. Ridging
further west will turn the upper level flow northwesterly,
positioning western and southwest Montana beneath the jet exit
region. A shortwave trough will move through this flow from
British Columbia to eastern Montana, causing a lee surface trough
to develop. The overall result is heavy mountain snow, areas of
light rain at low elevations, and strong winds across central
Montana. Little, if any precipitation is expected for western
portion of the central plains. Areas of light freezing rain are
possible tonight generally north and east of the Bears Paw
mountains as warmer air spreads over a colder airmass in northeast
Montana.

Wind gusts will strengthen along the Rocky Mountain Front early
Sunday where a high wind warning remains in effect. Strong wind
gusts will extend further east onto the adjacent plains, but the
high wind watch continues with lowered confidence that winds here
will reach warning criteria. Winter weather advisories now cover
the Rocky Mountains above 5000 feet and for the Central and
Southwest mountains above 5500 feet. Travelers through mountain
passes on Sunday should expect snow covered and icy roads. Snow
will be later to start in the Little Belt and other central
Montana ranges...and will likely continue later into Monday. Nutter

Monday night through Saturday...Shortwave ridge develops over the
region Monday night into Tuesday afternoon with dry conditions at
lower levels but scattered to numerous showers over the mountains.
Temperatures are expected to be generally near or above seasonal
averages. For Christmas Eve and Christmas Day...a Pacific storm
system will affect much of the region. At this time, it appears
that anticipated snow amounts west of a line from Cut Bank to
Lewistown should see 3 to 5 inches of snow over the plains with 6
to 15 inches in the mountains. For areas east of this line...snow
accumulations should range from 1 to 4 inches over the plains with
3 to 8 inches in the mountains. It should be noted that the record
snowfall for Great Falls on Christmas day is only 4.4 inches...and
we might have a chance at that record should a heavier snowband
move through Great Falls. Overall this is not a major storm...but
the timing for precipitation during a major holiday period will
affect travel. Temperatures will also trend colder from Wednesday
through Friday. There is the chance that temperatures on Christmas
Day could be a bit colder than currently forecast because of
clouds/snowfall. After this storm exits the region late
Thursday/early Friday...the weather pattern will become a bit less
active. There will be a small chance for a passing snow shower
over the weekend and into the New Years week...but no significant
snowfall is expected at this time. The main concern tonight is the
GFS13/EC are hinting at some very cold air moving into the region
by Tue Dec 30th...again this is a ways out...and things can change
a bit...but at this time current models are trying to bring down
another batch of arctic air before New Years. Brusda/mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  33  49  31  39 /  20  50  30  30
CTB  26  43  28  36 /  20  40  30  20
HLN  30  47  31  38 /  50  80  40  30
BZN  27  45  27  34 /  70  90  50  30
WEY  30  39  21  31 / 100 100  90  50
DLN  34  46  29  35 /  70  90  60  30
HVR  24  44  27  38 /  20  70  20  20
LWT  31  48  30  37 /  30  80  40  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern
Lewis and Clark...Jefferson...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.

HIGH WIND WATCH from late tonight through Sunday afternoon
Eastern Glacier...Eastern Pondera...Eastern Teton...Liberty...
Toole.

HIGH WIND WARNING until 5 PM MST Sunday Northern Rocky Mountain
Front...Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5500 FEET FOR Beaverhead...
Broadwater...Cascade...Gallatin...Judith Basin...Madison...
Meagher.

&&

$$

weather.gov/greatfalls
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AREA FORECAST DISCUSSION

NWS HASTINGS NE

 640 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 630 PM CST SAT DEC 20 2014

DENSE FOG IS ONCE AGAIN BEGINNING TO SETTLE IN OVER OUR EASTERN
FORECAST AREA BASED ON OBSERVATIONS AT GRI...JYR...AND AUH...WHICH
HAVE ALL GONE DOWN TO 1/4 SM IN THE LAST HOUR. FORECAST MODELS
INCLUDING THE RAP...HRRR...AND SREF ARE ALL INDICATING THE
POTENTIAL OF DENSE FOG FROM THE HASTINGS AND GRAND ISLAND AREAS
AND POINTS OFF TO THE NORTH AND EAST FROM THERE. IT IS HARD TO SAY
HOW FAR WEST AND SOUTH THE DENSE FOG WILL DEVELOP...BUT THERE IS
LESS MODEL SUPPORT FOR DENSE FOG AS YOU GET SOUTH AND WEST OF
HASTINGS. IT IS POSSIBLE THAT THE DENSE FOG ADVISORY MAY BE
EXPANDED TO THE SOUTH AND WEST LATER IN THE NIGHT BUT CONFIDENCE
IS NOT THERE TO GO ANY FURTHER SOUTH AND WEST WITH THE ADVISORY AT
THIS POINT IN TIME.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

SATELLITE SHOWS THE AREA OF PERSISTENT STRATUS IN THE EASTERN PART
OF THE FORECAST AREA HAS MOVED LITTLE IN THE PAST COUPLE HOURS BUT
THE THE HIGH CLOUDS MOVING OVER FROM THE WEST THE STRATUS IS
BECOMING MORE DIFFICULT TO SEE. IN THE STRATUS TEMPERATURES CONTINUE
TO STRUGGLE IN THE 30S...BUT AREAS WITH SUNSHINE HAVE WARMED MORE
THIS AFTERNOON.

MAIN CONCERN WITH THIS PERIOD ONCE AGAIN IS THE FOG CHANCES FOR
TONIGHT. A WEAK UPPER LEVEL WAVE MOVES THROUGH THE FORECAST AREA
LATE TONIGHT INTO SUNDAY. WITH THIS EXPECT THERE TO BE SOME HIGHER
CLOUDS THAT MOVE INTO THE AREA...BUT DRY CONDITIONS ARE EXPECTED.
THE LOW LEVEL MOISTURE CONTINUES ACROSS MUCH OF THE AREA THROUGH THE
NIGHT AND INTO SUNDAY. THE STRATUS SEEMS TO BE THE MOST PERSISTENT
IN THE NORTHEAST PART OF THE FORECAST AREA. THE RAP RELATIVE
HUMIDITY AT 925MB HAS BEEN FOLLOWING THE STRATUS THE BEST THIS
AFTERNOON AND THROUGH MOST OF THE NIGHT THE NORTHEAST REMAINS WITH
CLOUDS. IN THE SOUTHEAST THE HIGHER RELATIVE HUMIDITY BUILDS BACK
INTO THE AREA LATE TONIGHT. EXPECT THERE COULD BE SOME FOG NEAR THE
EDGES OF THE STRATUS. WILL KEEP PATCHY FOG ACROSS ALL BUT THE FAR
WEST AND AREAS OF FOG IN THE EAST WHERE THERE IS THE BEST CHANCE FOR
FOG SINCE VISIBILITY AT KJYR STILL HAS LOW VISIBILITY. ONCE AGAIN
THERE IS A POTENTIAL FOR SOME LOWER VISIBILITIES LATE TONIGHT INTO
SUNDAY MORNING AND EXPECT THE EAST IS THE BEST CHANCE.

BY SUNDAY MORNING THE WINDS WILL INCREASE A LITTLE BIT FROM THE
SOUTH. THIS WILL HELP TO MIX THINGS UP A BIT AND THE FOG AND STRATUS
MAY FINALLY MOVE OUT OF THE AREA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

THE BIGGEST CHALLENGE WILL BE DETERMINING PRECIPITATION CHANCES.

WE KICK OFF THE LONG TERM SUNDAY NIGHT WITH A LONGWAVE TROUGH AXIS
OVER THE GREAT PLAINS...AS A STRONG JET HEADS IN ON THE BACKSIDE OF
THE TROUGH..FROM THE PACIFIC NORTHWEST INTO THE GREAT BASIN. MOST OF
THE ENERGY IS ASSOCIATED WITH THE CLOSED LOW IN THE NORTHERN
PLAINS...SO I AM NOT GOING ALL THAT HIGH WITH CHANCES HERE. A
SMALLER SHORTWAVE TROUGH WITHIN THE LONGWAVE TROUGH WILL HELP KICK
SOMETHING UP IN THE EVENING...THE WAY IT LOOKS NOW...BUT SMALL
FEATURES ARE DIFFICULT TO BE VERY EXACT WITH TIMING.  KEEPING THIS
ALL RAIN AS TEMPERATURES DO NOT APPEAR TO BECOME COLD ENOUGH BEFORE
THE PRECIPITATION EXITS WITH THIS PERTURBATION. ANOTHER PERTURBATION
WORKS AROUND THE TROUGH BY MONDAY NIGHT/TUESDAY. TEMPERATURE
PROFILES APPEAR TO SUPPORT SOME LIGHT SNOW MONDAY NIGHT INTO
TUESDAY. PRECIPITATION/SNOW AMOUNTS ARE EXPECTED TO BE LIGHT...WITH
SNOW ACCUMULATION NO MORE THAN AN INCH ANTICIPATED WITH THIS NEXT
PIECE OF ENERGY. AGAIN...CONFIDENCE IS NOT THE HIGHEST WITH
EXACT TIMING.

FLOW IS QUITE PROGRESSIVE AND YET ANOTHER TROUGH MAKES ITS WAY INTO
THE ROCKIES. A PIECE OF ENERGY IS EXPECTED TO BREAK OFF AHEAD OF THE
MAIN WAVE...BUT LOOKS MORE FOCUSED JUST NORTH OF THE CWA. WE COULD
GET SOME SNOW OUT OF THIS...BUT AGAIN...DOES NOT LOOK LIKE WE WILL
GET A LOT OUT OF SNOW. WE SHOULD GET A NOTICEABLE COOL DOWN FRIDAY
BEHIND THE ASSOCIATED COLD FRONT. HIGHS WILL ONLY BE IN THE LOWER TO
MID 30S AND THE WIND COULD BE QUITE GUSTY FROM THE
NORTHWEST...MAKING THE DAY AFTER CHRISTMAS POTENTIALLY BRISK AND
UNCOMFORTABLE.

&&

.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 630 PM CST SAT DEC 20 2014

THE PRIMARY CONCERN WILL CENTER AROUND THE POSSIBILITY OF DENSE
FOG. IT IS A SURE BET THAT WE WILL SEE SOME DENSE FOG AT KGRI AS
IT IS ALREADY HAPPENING. MY HUNCH WOULD BE THAT THE FOG WILL
FLUCTUATE AT TIMES AT KGRI...BUT THAT MUCH OF THE NIGHT COULD BE
TOTALLY SOCKED IN UNDER THE FOG WITH LIFR CONDITIONS. KEAR MAY
VERY WELL STAY WEST OF THE FOG TONIGHT AND WILL GO WITH PRIMARILY
MVFR OR VFR CONDITIONS AT KEAR TONIGHT...ALTHOUGH CAN NOT
COMPLETELY RULE OUT THE FOG SPREADING EAST INTO KEAR LATE TONIGHT
OR EARLY SUNDAY MORNING.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 11 AM CST SUNDAY FOR NEZ039>041-047>049-
     062>064-075>077-087.

KS...NONE.
&&

$$

UPDATE...WESELY
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...WESELY




AREA FORECAST DISCUSSION

NWS HASTINGS NE

 243 PM CST FRI DEC 19 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM CST FRI DEC 19 2014

SATELLITE AND OBSERVATIONS SHOW THE EDGE OF THE LOW CLOUDS IN THE
FAR WESTERN PART OF THE FORECAST AREA. FOG HAS BEEN PERSISTENT NEAR
THE EDGE OF THE LOW CLOUDS. VISIBILITIES HAVE IMPROVED IN THE PAST
HOUR OR SO...BUT SOME LIGHT FOG PERSISTS.

WATCHING THE VERY SLOW PROGRESSION OF THE CLOUDS TO THE EAST HAVE
BEEN INCLINED TO KEEP THE CLOUDS LONGER THAN EARLIER THOUGHT. UNDER
THE CLOUDS THE WINDS ARE FROM THE SOUTH OR EVEN THE SOUTHEAST A BIT
AND THIS HAS MADE IT HARD FOR THE CLEARING LINE TO CONTINUE MOVING
TO THE EAST. ON THE OTHER HAND UNDER THE CLEAR SKIES THE WINDS ARE
FROM THE WEST AND SHOULD BE PUSHING DRIER AIR DOWN SLOPE WHICH
SHOULD HELP THE CLEARING. AT THIS TIME THE SOUTH WINDS SEEM TO BE
WINNING THAT BATTLE.

TWO MAIN QUESTIONS REMAIN FOR THE FORECAST. FIRST HOW FAR EAST WILL
THE CLOUDS MOVE AND SECOND WHETHER THERE WILL BE FOG NEAR THE EDGE
OF THE STRATUS. A BROAD SURFACE TROUGH JUST TO THE WEST OF THE
FORECAST AREA WILL MOVE TO THE EAST DURING THE NIGHT. THIS SHOULD
HELP WINDS TO TURN TO THE WEST EVEN THOUGH THEY SHOULD BE LIGHT.
EXPECT THAT THE WEST WINDS WILL HELP TO PUSH THE CLOUDS TO THE EAST
A LITTLE DURING THE NIGHT. CLOUDS SHOULD HOLD TOUGH IN THE
EAST...BUT THE WEST ESPECIALLY AND EVEN THE CENTRAL PART OF THE
FORECAST AREA COULD SEE SOME CLEARING DURING THE NIGHT. THAT BRINGS
WITH IT THE COOLING TEMPERATURES THAT HAVE BEEN EVIDENT IN THE WEST
DURING THE MORNING TODAY. COOLER TEMPERATURES AND LIGHT WINDS SHOULD
ALLOW FOR SOME FOG ACROSS THE AREA. HOW MUCH...WHERE AND HOW LOW
WILL BE VISIBILITY BE ARE ALL QUESTIONS THAT PROVIDE A CHALLENGE.
SINCE MANY LOCATIONS ACROSS THE FORECAST AREA HAVE YET VISIBILITY OF
MORE THAN 5 MILES...WILL MAKE THE ASSUMPTION THAT THE LIGHT FOG
SHOULD LIFT A LITTLE THIS AFTERNOON...BUT RETURN DURING THE NIGHT.
HAVE KEPT PATCHY FOG ACROSS THE FORECAST AREA LATE TONIGHT. THE
LOWEST VISIBILITIES WILL BE NEAR THE EDGE OF THE CLOUDS. CURRENTLY
THE NAM AND HRRR ARE THE ONLY MODELS THAT INDICATE THERE WOULD BE
SOME FOG AROUND THE AREA. THE NAM KEEPS IT FURTHER TO THE EAST AND
FAIRLY LIGHT WHILE THE HRRR GIVES SOME LOWER VISIBILITIES FURTHER
WEST. WITH THE CURRENT FORECAST FOR WHERE THE CLEARING LINE WILL BE
LATE TONIGHT EXPECT THE LOWEST VISIBILITIES TO BE IN THE CENTRAL
PART OF THE FORECAST AREA BUT NOT SURE HOW LOW THE VISIBILITY WILL
BE...ALTHOUGH WITH THE PAST FEW NIGHTS AS A MODEL EXPECT THERE COULD
BE SOME VISIBILITIES LESS THAN A MILE SOMEWHERE.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM CST FRI DEC 19 2014

A PROGRESSIVE WEST NORTHWESTERLY FLOW IS EXPECTED TO BE IN PLACE
ACROSS THE REGION TO START THE EXTENDED PERIODS...WITH AN UPPER
LEVEL SHORTWAVE ACROSS THE PACIFIC NORTHWEST FORECAST TO DIVE INTO
THE PLAINS SUNDAY NIGHT THROUGH MONDAY. AS THIS DISTURBANCE DEEPENS
ACROSS THE MISSISSIPPI RIVER VALLEY AND TRACKS INTO THE GREAT LAKES
REGION...NORTHWESTERLY FLOW WILL PERSIST ALOFT...AND COULD SEE
ANOTHER UPPER LEVEL WAVE DIVE ACROSS THE LOCAL AREA TUESDAY NIGHT OR
WEDNESDAY. WHILE MODELS DISAGREE ON THE TIMING OF THIS NEXT
WAVE...THEY DIVERGE EVEN MORE AS WE TRANSITION INTO CHRISTMAS DAY
AND BEYOND...WITH THE EC STILL MAINTAINING A MUCH BROADER TROUGH
ACROSS THE WESTERN STATES AND THE GFS KEEPS THIS NEXT DISTURBANCE
MUCH FURTHER NORTH. DUE TO THE DIVERGENCE OF THE GUIDANCE...BLENDED
FORECAST DROPPED POPS FOR CHRISTMAS NIGHT AND THE DAY AFTER...AND
GIVEN THE UNCERTAINTY...SAW NO REASON TO TINKER WITH THE CHANCE OF
SNOW FOR THE TIME BEING.

STARTING OFF SUNDAY...EXPECT THE LOW LEVEL STRATUS THAT HAS BEEN
PERSISTENT ACROSS THE LOCAL AREA FOR MUCH OF THE LAST 10 DAYS TO BE
EAST OF THE LOCAL AREA AND CLOSER TO THE MISSOURI RIVER IN RESPONSE
TO A SURFACE TROUGH SLOWLY PUSHING ACROSS THE CENTRAL PLAINS. WITH
THE FOCUS OF SOME FOG ON THE WESTERN EDGE OF THIS STRATUS THE PAST
FEW DAYS...THINK IT IS PROBABLE THAT WE MIGHT STILL SEE SOME FOG
FROM ROUGHLY HIGHWAY 281 EASTWARD TO START THE DAY SUNDAY...CLOSER
TO THE EDGE OF THE STRATUS. AS A RESULT OF THIS...OPTED TO INTRODUCE
PATCHY FOG TO THE FORECAST FOR THIS AREA SUNDAY MORNING.
THEREAFTER...THE SURFACE FLOW IS EXPECT TO SHIFT AND BECOME MORE
WESTERLY THROUGH THE DAY SUNDAY...AND THIS DOWNSLOPING COMPONENT OF
THE WIND COMBINED WITH AT LEAST PARTLY SUNNY SKIES...SHOULD MAKE FOR
A RELATIVELY NICE FINISH TO THE WEEKEND...WITH TEMPERATURES EXPECTED
TO CLIMB INTO THE 40S SUNDAY AFTERNOON.

BEHIND THE SURFACE TROUGH...EXPECT THE NEXT UPPER LEVEL DISTURBANCE
TO SLIDE ACROSS THE LOCAL AREA LATE SUNDAY NIGHT INTO
MONDAY...BRINGING MAINLY THE CHANCE FOR RAIN TO THE LOCAL AREA.
BRIEFLY CONTEMPLATED INTRODUCING A RAIN SNOW MIX FOR THE EARLY
MORNING HOURS MONDAY GIVEN SURFACE TEMPS NEAR FREEZING...BUT LOOKING
AT THE ATMOSPHERIC PROFILE AND WARM LAYER ALOFT...THIS THE IS LIKELY
TO BE MAINLY A LIGHT RAIN EVENT FOR THE MAJORITY OF THE AREA. AS THE
MAIN UPPER LEVEL LOW MOVES INTO THE MISSISSIPPI RIVER VALLEY MONDAY
AFTERNOON...EXPECT SOME WRAP AROUND MOISTURE TO POTENTIALLY CLIP THE
NORTHERN AND EASTERN PORTIONS OF THE FORECAST AREA MONDAY NIGHT INTO
TUESDAY...WITH A LIGHT DUSTING OF SNOW POSSIBLE OVER THIS PERIOD. AS
THE FLOW REMAINS NORTHWESTERLY ALOFT BEHIND THE DEPARTING SYSTEM...A
SECONDARY UPPER LEVEL WAVE IS PROGGED TO CROSS THE NORTHERN AND
CENTRAL PLAINS TUESDAY NIGHT OR WEDNESDAY. DUE TO DIFFERENCES IN
GUIDANCE...THE CONFIDENCE OF ANY PRECIP OVER THIS PERIOD IS LOW AND
KEPT TEMPERATURES SEASONAL AND FORECAST DRY TUESDAY NIGHT THROUGH
CHRISTMAS DAY AS A RESULT.

THEREAFTER...WHAT LOOKED LIKE A DECENT CHANCE FOR SNOW LATE IN THE
EXTENDED PERIODS APPEARS A BIT MORE IN QUESTION THIS AFTERNOON AS
SIGNIFICANT DIFFERENCES IN THE HANDLING OF THE NEXT SYSTEM ARE
APPARENT. AS A RESULT...AS PREVIOUSLY MENTIONED...SAW NO REASON TO
DIVERGE FROM BLENDED FORECAST AS CONFIDENCE IN ANY ONE PARTICULAR
SOLUTION IS LOW THIS FAR OUT.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1120 AM CST FRI DEC 19 2014

FOG HAS BEEN PERSISTENT IN THE KEAR TERMINAL AREA...BUT THERE HAS
BEEN SOME LIGHT FOG IN THE KGRI TERMINAL AREA. EXPECT THERE WILL
BE AN IMPROVEMENT IN VISIBILITY THIS AFTERNOON. THE LOW CLOUDS
CONTINUE TO PROVE A CHALLENGE. THE WESTERN EDGE OF THE CLOUDS IS
TO THE WEST OF KEAR AND EXPECT THAT THERE COULD BE SOME BREAKS IN
THE LOW CLOUDS IN THE KEAR TERMINAL AREA...BUT DO NOT EXPECT IT TO
GET INTO KGRI. ONCE THE LOWER CLOUDS MOVE OUT THERE WILL LIKELY BE
SOME FOG REFORMING DURING THE OVERNIGHT HOURS.


&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...JCB
LONG TERM...ROSSI
AVIATION...JCB



AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 1222 PM CST FRI DEC 19 2014

.SYNOPSIS...
ISSUED AT 328 AM CST FRI DEC 19 2014

A SURFACE RIDGE OF HIGH PRESSURE EXTENDS ACROSS THE GREAT LAKES REGION.
A SUBSTANTIAL AREA OF STRATUS EXTENDS ALONG THE WESTERN PERIPHERY OF
THE SURFACE HIGH ACROSS THE EASTERN DAKOTAS...THE EASTERN HALF OF
NEBRASKA AND MOST OF KANSAS. ON THE WESTERN EDGE OF THE
STRATUS...LOCALLY DENSE FOG TO A QUARTER MILE CONTINUES FROM NEAR
HAYES CENTER THROUGH NORTH PLATTE...BROKEN BOW AND BASSETT. FURTHER
EAST WITHIN THE STRATUS...PATCHY FOG WITH CURRENT VSBYS FROM 2-5SM.
TEMPERATURES IN WESTERN NEBRASKA RANGING FROM 29 AT ONL TO 12 AT
VTN.

&&

.UPDATE...
ISSUED AT 1222 PM CST FRI DEC 19 2014

PATCHY FOG CONTINUES TO HANG AROUND INTO THE MID AFTERNOON IN
HOLT...WHEELER AND GARFIELD COUNTIES...THE SLOWER EROSION IS
SIMILAR TO WHAT THE HRRR HAS BEEN SUGGESTING THOUGH THE HRRR ALSO
KEEP LOWER VSBYS ALL AFTERNOON. ACTUAL FCST HAS INCREASED VSBYS
LATER THIS AFTERNOON THERE...BUT CURRENT FCST HAS A REFORMATION
LATER THIS EVENING WHICH STILL LOOKS GOOD...THOUGH THE AREA MAY BE
REDEFINED A BIT. OTHERWISE THE MAXS TODAY WERE WARMED SLIGHTLY IN
THE CENTRAL SANDHILLS WHERE TEMPS SEEMS TO WARM MORE QUICKLY...BUT
THINK WARMEST MAXES WILL BE IN SNOW-FREE AREA OF HAYES AND
FRONTIER COUNTIES.

UPDATE ISSUED AT 953 AM CST FRI DEC 19 2014

HAVE DELAYED THE DISSIPATION OF THE FOG IN THE EASTERN PORTION OF
THE AREA FOR AN HOUR. LATEST SHORT RANGE MODELS INDICATE CLOUDS
MAY NOT FULLY CLEAR IN ERN HOLT AND ERN CUSTER COUNTIES...THOUGH
CURRENT SATELLITE TRENDS INDICATE MORE CLEARING THAN MODELS
SUGGEST. TEMPERATURES WILL BE HIGHLY DEPENDENT ON CLOUD COVER IN
THE EAST...AND EFFECT OF SNOW COVER WHERE SUN DOES SHINE.
OTHERWISE WITH LIGHT WINDS THE DAY SHOULD BE MORE QUIET THAN DAYS PAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CST FRI DEC 19 2014

LOCALLY DENSE FOG ALONG THE WESTERN EDGE OF STRATUS WITH PATCHY FOG
FURTHER EAST TO PERSIST THROUGH MID MORNING ACROSS THE SOUTHEASTERN
ZONES. ONCE FOG BURNS OFF...STRATUS WILL SLOWLY CLEAR EAST OF A
BROKEN BOW THROUGH ONEILL LINE THIS AFTERNOON. TO THE WEST...MOSTLY
SUNNY SKIES. WITH SLIGHTLY WARMER H85 TEMPS TO NEAR 3C FROM VTN
SOUTHWEST THROUGH OGA AND IML SUPPORT HIGHS IN THE UPPER 30S TO NEAR
40. WITH LIGHT WINDS REMAINING SOUTH AND STRATUS LINGERING INTO THE
AFTERNOON AT ONL AND BARTLETT...HIGHS LIMITED TO THE LOWER 30S.
CURRENT FORECAST TO BE NEAR...BUT SLIGHTLY COOLER THAN MAV GUIDANCE
ALL AREAS DUE TO EXISTING SNOW COVER EFFECTS.

FOR TONIGHT...STRATUS SHOULD REMAIN JUST EAST OF THE FAR EASTERN
ZONES. EXPECTING AN INCREASING IN SOME MID AND HIGH CLOUDINESS AS AN
UPSTREAM DISTURBANCE TRACKS ACROSS MONTANA AND WYOMING. SUBSTANTIAL
ONSHORE MOISTURE WILL STREAM INTO THE PACIFIC NORTHWEST WITH
APPROACH OF A STRONGER DISTURBANCE. LOWS TO FALL  INTO THE MID
TEENS...WITH COLDER LOWS NEAR 10 ABOVE EASTERN PANHANDLE INTO THE
PLATTE RIVER VALLEY.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CST FRI DEC 19 2014

12Z SATURDAY AND BEYOND. WEAK SURFACE TROUGH WILL RESIDE EAST OF
THE FORECAST AREA ON SATURDAY...PROVIDING FOR LIGHT WESTERLY
DOWNSLOPING FLOW OFF THE HIGH PLAINS. THIS WILL ALLOW FOR PARTIAL
CLEARING AND A WEAK PUSH OF WARM AIR ADVECTION OFF THE HIGHER
TERRAIN. H85 TEMPERATURES WARM SEVERAL DEGREES ABOVE 0C...WHICH
WILL PROVIDE FOR SFC HIGHS IN THE LOWER 40S...WITH SOME UPPER 30S
ACROSS THE FAR NORTHEAST WHERE FOG AND/OR STRATUS REMAINS IN THE
FORECAST SATURDAY MORNING. LATE SATURDAY AFTERNOON AND EVENING A
WEAK WAVE WILL DROP SOUTHEAST FROM THE NORTHERN ROCKIES ONTO THE
NORTHERN PLAINS. THIS WILL FORCE A WEAK BOUNDARY THROUGH WESTERN
NEBRASKA...EFFECTIVELY KEEPING THE BL SOMEWHAT MIXED. THE RESULT
WILL BE SLIGHTLY WARMER OVERNIGHT LOWS...WITH TEENS ANTICIPATED
WHERE THE ATMOSPHERE CAN FULLY DECOUPLE /RIVER VALLEYS/...BUT
LOWER 20S ELSEWHERE. SUNDAY...TEMPERATURES WARM ONCE AGAIN AS A
LEE TROUGH DEEPENS AND ALLOWS FOR A RETURN TO A SOUTHWESTERLY
TRAJECTORY OF THE LOWER TROPOSPHERIC FLOW. H85 TEMPS WARM TO NEAR
5C ACROSS MUCH OF THE SANDHILLS...THIS SHOULD TRANSLATE TO MID TO
UPPER 40S OVER MUCH OF THE REGION SUNDAY AFTERNOON. SUNDAY EVENING
THROUGH MONDAY...ALL AVAILABLE GUIDANCE INDICATES A SHORTWAVE
DIVING SOUTH ACROSS THE PLAINS. SUFFICIENT LIFT AND MOISTURE IS
SHOWN FOR PRECIPITATION WITHIN THE REGION...BUT SUBTLE DIFFERENCES
IN THE WAY THE LONGER RANGE MODELS HANDLE THE UPPER JET STRUCTURE
CREATES UNCERTAINTY IN THE FORECAST. THE GFS CONTINUES TO BE
SLIGHTLY EAST WITH THE STRONGER JET SUPPORT...WHILE THE ECMWF IS
SLIGHTLY WEST. THUS THERES A DISAGREEMENT ON WHERE THE STRONGEST
MID LEVEL FRONTOGENETIC FORCING WILL RESIDE...THE GFS FAVORS THE
EASTERN PANHANDLE SOUTHEAST THROUGH LINCOLN AND CUSTER
COUNTIES...THE EURO IS WEST OVER THE HIGHER TERRAIN OF
COLORADO/WYOMING. FOR THIS...DIDN/T GET TOO CARRIED AWAY ON POPS
JUST YET...MAINTAINING A SLIGHT CHANCE/LOW END CHANCE WORDING. IF
PRECIP OCCURS THERMO PROFILES INITIALLY FAVOR ALL RAIN ACROSS THE
FORECAST AREA SUNDAY EVENING...BUT ENOUGH UNCERTAINTY REMAINS
OVERNIGHT TO KEEP A MENTION OF RAIN OR SNOW GOING...ESPECIALLY
GOING INTO MONDAY AS THE GFS INDICATES A GOOD PUSH OF SUB 0C H85
AIR ACROSS THE FORECAST AREA...THE EC IS SLOWER TO ARRIVE WITH THE
COLD AIR. LIGHT QPF MAY CONTINUE INTO TUESDAY ACROSS OUR EAST AS
THE UPPER FLOW TURNS NORTHERLY AND ADDITIONAL UL ENERGY DIVE SOUTH
ACROSS THE PLAINS. TEMPERATURE PROFILES WOULD BE SUPPORTIVE OF ALL
SNOW AT THIS POINT.

THERE REMAINS A STRONG SIGNAL THAT A ROBUST UPPER LEVEL TROUGH WILL
DROP SOUTH INTO THE PACIFIC NORTHWEST MID-WEEK THEN PROCEED TOWARD
THE GREAT BASIN AND EVENTUALLY EMERGE ON THE PLAINS. THE MODELS ARE
ALSO SUGGESTING INCREASED FRONTOGENESIS ALONG/BEHIND A STRONG ARCTIC
FRONT POISED TO ARRIVE ATOP THE SANDHILLS ON CHRISTMAS.  THE MODELS
CONTINUE TO WAFFLE A BIT ON THE PROJECTED SYSTEM...BUT CONFIDENCE IS
SLOWLY INCREASING IN A POTENTIAL WINTER STORM FOR CHRISTMAS AND LATE
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1132 AM CST FRI DEC 19 2014

MAINLY VFR FOR THE KVTN AND KLBF TAF PERIOD...HOWEVER THERE IS
STILL SOME POTENTIAL FOR FOG IN THE KLBF TAF PERIOD TWD EARLY
MORNING. WITH FULL SUNSHINE TODAY AND LIGHT WINDS THROUGH THE DAY
LITTLE VERTICAL MIXING OF THE MOIST BOUNDARY LAYER...A RESULT OF
MELTING SNOW...WILL OCCUR. THEREFORE AS TRANSIENT UPPER LEVEL HIGH
PRESSURE BUILDS IN THE PATTERN APPEARS POSSIBLE FOR FOG
DEVELOPMENT...ESPECIALLY IN RIVER VALLEY AREAS SUCH AS KLBF.
HOWEVER...SHORT RANGE HIGH RESOLUTION MODELS ARE NOT SUGGESTING
REDUCED VSBYS THIS FAR WEST OVERNIGHT AND THEREFORE CONFIDENCE IS
NOT HIGH ON THE 5SM BR FOR KLBF.

FOG REOCCURRANCE IS LIKELY ACROSS THE FAR EASTERN PORTION OF THE
FORECAST AREA OVERNIGHT...EAST OF A LINE FROM ATKINSON TO BROKEN BOW TO
STOCKVILLE.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JWS
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...JACOBS
AVIATION...JWS






AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 328 AM CST FRI DEC 19 2014

.SYNOPSIS...
ISSUED AT 328 AM CST FRI DEC 19 2014

A SURFACE RIDGE OF HIGH PRESSURE EXTENDS ACROSS THE GREAT LAKES REGION.
A SUBSTANTIAL AREA OF STRATUS EXTENDS ALONG THE WESTERN PERIPHERY OF
THE SURFACE HIGH ACROSS THE EASTERN DAKOTAS...THE EASTERN HALF OF
NEBRASKA AND MOST OF KANSAS. ON THE WESTERN EDGE OF THE
STRATUS...LOCALLY DENSE FOG TO A QUARTER MILE CONTINUES FROM NEAR
HAYES CENTER THROUGH NORTH PLATTE...BROKEN BOW AND BASSETT. FURTHER
EAST WITHIN THE STRATUS...PATCHY FOG WITH CURRENT VSBYS FROM 2-5SM.
TEMPERATURES IN WESTERN NEBRASKA RANGING FROM 29 AT ONL TO 12 AT
VTN.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CST FRI DEC 19 2014

LOCALLY DENSE FOG ALONG THE WESTERN EDGE OF STRATUS WITH PATCHY FOG
FURTHER EAST TO PERSIST THROUGH MID MORNING ACROSS THE SOUTHEASTERN
ZONES. ONCE FOG BURNS OFF...STRATUS WILL SLOWLY CLEAR EAST OF A
BROKEN BOW THROUGH ONEILL LINE THIS AFTERNOON. TO THE WEST...MOSTLY
SUNNY SKIES. WITH SLIGHTLY WARMER H85 TEMPS TO NEAR 3C FROM VTN
SOUTHWEST THROUGH OGA AND IML SUPPORT HIGHS IN THE UPPER 30S TO NEAR
40. WITH LIGHT WINDS REMAINING SOUTH AND STRATUS LINGERING INTO THE
AFTERNOON AT ONL AND BARTLETT...HIGHS LIMITED TO THE LOWER 30S.
CURRENT FORECAST TO BE NEAR...BUT SLIGHTLY COOLER THAN MAV GUIDANCE
ALL AREAS DUE TO EXISTING SNOW COVER EFFECTS.

FOR TONIGHT...STRATUS SHOULD REMAIN JUST EAST OF THE FAR EASTERN
ZONES. EXPECTING AN INCREASING IN SOME MID AND HIGH CLOUDINESS AS AN
UPSTREAM DISTURBANCE TRACKS ACROSS MONTANA AND WYOMING. SUBSTANTIAL
ONSHORE MOISTURE WILL STREAM INTO THE PACIFIC NORTHWEST WITH
APPROACH OF A STRONGER DISTURBANCE. LOWS TO FALL  INTO THE MID
TEENS...WITH COLDER LOWS NEAR 10 ABOVE EASTERN PANHANDLE INTO THE
PLATTE RIVER VALLEY.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CST FRI DEC 19 2014

12Z SATURDAY AND BEYOND. WEAK SURFACE TROUGH WILL RESIDE EAST OF
THE FORECAST AREA ON SATURDAY...PROVIDING FOR LIGHT WESTERLY
DOWNSLOPING FLOW OFF THE HIGH PLAINS. THIS WILL ALLOW FOR PARTIAL
CLEARING AND A WEAK PUSH OF WARM AIR ADVECTION OFF THE HIGHER
TERRAIN. H85 TEMPERATURES WARM SEVERAL DEGREES ABOVE 0C...WHICH
WILL PROVIDE FOR SFC HIGHS IN THE LOWER 40S...WITH SOME UPPER 30S
ACROSS THE FAR NORTHEAST WHERE FOG AND/OR STRATUS REMAINS IN THE
FORECAST SATURDAY MORNING. LATE SATURDAY AFTERNOON AND EVENING A
WEAK WAVE WILL DROP SOUTHEAST FROM THE NORTHERN ROCKIES ONTO THE
NORTHERN PLAINS. THIS WILL FORCE A WEAK BOUNDARY THROUGH WESTERN
NEBRASKA...EFFECTIVELY KEEPING THE BL SOMEWHAT MIXED. THE RESULT
WILL BE SLIGHTLY WARMER OVERNIGHT LOWS...WITH TEENS ANTICIPATED
WHERE THE ATMOSPHERE CAN FULLY DECOUPLE /RIVER VALLEYS/...BUT
LOWER 20S ELSEWHERE. SUNDAY...TEMPERATURES WARM ONCE AGAIN AS A
LEE TROUGH DEEPENS AND ALLOWS FOR A RETURN TO A SOUTHWESTERLY
TRAJECTORY OF THE LOWER TROPOSPHERIC FLOW. H85 TEMPS WARM TO NEAR
5C ACROSS MUCH OF THE SANDHILLS...THIS SHOULD TRANSLATE TO MID TO
UPPER 40S OVER MUCH OF THE REGION SUNDAY AFTERNOON. SUNDAY EVENING
THROUGH MONDAY...ALL AVAILABLE GUIDANCE INDICATES A SHORTWAVE
DIVING SOUTH ACROSS THE PLAINS. SUFFICIENT LIFT AND MOISTURE IS
SHOWN FOR PRECIPITATION WITHIN THE REGION...BUT SUBTLE DIFFERENCES
IN THE WAY THE LONGER RANGE MODELS HANDLE THE UPPER JET STRUCTURE
CREATES UNCERTAINTY IN THE FORECAST. THE GFS CONTINUES TO BE
SLIGHTLY EAST WITH THE STRONGER JET SUPPORT...WHILE THE ECMWF IS
SLIGHTLY WEST. THUS THERES A DISAGREEMENT ON WHERE THE STRONGEST
MID LEVEL FRONTOGENETIC FORCING WILL RESIDE...THE GFS FAVORS THE
EASTERN PANHANDLE SOUTHEAST THROUGH LINCOLN AND CUSTER
COUNTIES...THE EURO IS WEST OVER THE HIGHER TERRAIN OF
COLORADO/WYOMING. FOR THIS...DIDN/T GET TOO CARRIED AWAY ON POPS
JUST YET...MAINTAINING A SLIGHT CHANCE/LOW END CHANCE WORDING. IF
PRECIP OCCURS THERMO PROFILES INITIALLY FAVOR ALL RAIN ACROSS THE
FORECAST AREA SUNDAY EVENING...BUT ENOUGH UNCERTAINTY REMAINS
OVERNIGHT TO KEEP A MENTION OF RAIN OR SNOW GOING...ESPECIALLY
GOING INTO MONDAY AS THE GFS INDICATES A GOOD PUSH OF SUB 0C H85
AIR ACROSS THE FORECAST AREA...THE EC IS SLOWER TO ARRIVE WITH THE
COLD AIR. LIGHT QPF MAY CONTINUE INTO TUESDAY ACROSS OUR EAST AS
THE UPPER FLOW TURNS NORTHERLY AND ADDITIONAL UL ENERGY DIVE SOUTH
ACROSS THE PLAINS. TEMPERATURE PROFILES WOULD BE SUPPORTIVE OF ALL
SNOW AT THIS POINT.

THERE REMAINS A STRONG SIGNAL THAT A ROBUST UPPER LEVEL TROUGH WILL
DROP SOUTH INTO THE PACIFIC NORTHWEST MID-WEEK THEN PROCEED TOWARD
THE GREAT BASIN AND EVENTUALLY EMERGE ON THE PLAINS. THE MODELS ARE
ALSO SUGGESTING INCREASED FRONTOGENESIS ALONG/BEHIND A STRONG ARCTIC
FRONT POISED TO ARRIVE ATOP THE SANDHILLS ON CHRISTMAS.  THE MODELS
CONTINUE TO WAFFLE A BIT ON THE PROJECTED SYSTEM...BUT CONFIDENCE IS
SLOWLY INCREASING IN A POTENTIAL WINTER STORM FOR CHRISTMAS AND LATE
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1122 PM CST THU DEC 18 2014

LIFR IS EXPECTED THROUGH AT LEAST 10Z AT KLBF. THE MODELS SHOW A
SLUG OF DRY AIR ALOFT MOVING THROUGH THIS AREA. THE RAP AND HRRR
SHOW THE FOG EXITING KLBF AROUND 15Z. THE NAM IS A BIT QUICKER.
THIS CONDITIONS WILL BE FAVORABLE FOR LIFR THROUGH 10Z BUT FLIGHT
CONDITIONS MAY IMPROVE 10Z-14Z...SOONER THAN FORECAST.

VFR IS EXPECTED ELSEWHERE OVERNIGHT AND FRIDAY EXCEPT ALONG AND
EAST OF A LINE FROM KANW-KLBF WHERE MVFR/LOCAL LIFR WILL CONTINUE
THROUGH 21Z. THIS AREA OF LOW CLOUDS AND FOG SHIFTS SLOWLY EAST
FRIDAY.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...JACOBS
AVIATION...CDC









AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

 1122 PM CST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 307 PM CST THU DEC 18 2014

H5 ANALYSIS FROM THIS MORNING REMAINED ACTIVE ACROSS THE
LOWER 48 STATES. A CLOSED LOW WAS PRESENT ALONG THE MAINE ATLANTIC
COAST. FURTHER WEST...A SHORTWAVE WAS NOTED OVER CENTRAL SOUTH
DAKOTA...WITH A SECOND SHORTWAVE OVER CENTRAL KS AND A THIRD SHORTWAVE
OVER SWRN AZ. HT FALLS OF 50 TO 80 METERS...IN ASSOCIATION WITH THE
DISTURBANCE IN KANSAS...WERE NOTED OVER MISSOURI AND NRN OK. SOUTH
OF THE KANSAS DISTURBANCE...A 50 TO 70 KT JET STREAK EXTENDED FROM
SERN NM INTO THE MID ATLANTIC AND CANADIAN MARITIMES. AT THE
SURFACE...FOG AND STRATUS DOMINATED CENTRAL AND EASTERN PORTIONS OF
THE FORECAST AREA TDY WITH SOME CLEARING NOTED IN THE EASTERN
NEBRASKA PANHANDLE...AS WELL AS THE WESTERN SANDHILLS AND FAR SWRN
NEBRASKA. TEMPERATURES AS OF 3 PM CST RANGED FROM 27 AT AINSWORTH
AND VALENTINE TO 30 AT THEDFORD.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 307 PM CST THU DEC 18 2014

THE MAIN FORECAST CONCERNS OVER THE SHORT TERM ARE THE TEMPERATURES
AND THE POTENTIAL FOR FOG FORMATION.

IN ASSOCIATION WITH THE MOIST RETURN FLOW FROM THE SURFACE HIGH
PRESSURE SITUATED OVER THE UPPER MIDWEST...LOW STRATUS WILL CONTINUE
MOVING SLOWLY EASTWARD THIS EVENING AND TONIGHT ACROSS THE FORECAST
AREA. RELATIVELY DRIER AIR ASSOCIATED WITH A WEST WIND MOVES INTO THE
PANHANDLE AND FAR WESTERN COUNTIES TONIGHT...KEEPING THE SKY
RELATIVELY CLOUD FREE. THE 18/12Z MODEL RUNS...ESPECIALLY THE NAM
AND RAP...AND CURRENT TRENDS IN THE VISIBLE SATELLITE IMAGES BRING
THE BACK EDGE OF THE STRATUS TO THE HIGHWAY 83 CORRIDOR BY 19/00Z.
LIGHT WINDS AND A CLEARING SKY WILL ALLOW THE ATMOSPHERE TO DECOUPLE
OVERNIGHT...AND WITH DEW POINT DEPRESSIONS GENERALLY THREE DEGREES
OR LESS...FOG FORMATION IS FAVORABLE ALONG THE EDGE OF THE STRATUS
DECK. MIN TEMPS HAVE BEEN ADJUSTED DOWNWARD FROM THE PREVIOUS
FORECAST WEST OF HIGHWAY 83 TO ACCOUNT FOR THE DECOUPLING AND AN
EXISTING SNOW PACK IN MANY LOCATIONS. OVER NORTH CENTRAL NEBRASKA...WHERE
STRATUS IS EXPECTED TO REMAIN THROUGH THE NIGHT...HAVE KEPT MIN
TEMPS A FEW DEGREES WARMER.

FRIDAY...ANY FOG SHOULD BURN OFF BY 19/15Z AND MAX TEMPS WILL REFLECT
THE AMOUNT OF CLOUD COVER. DESPITE MOSTLY CLEAR SKIES AND WEST WINDS
FOR THE WESTERN 2/3 OF THE FORECAST AREA...HIGHS WILL STILL BE IN
THE UPPER 30S TO LOWER 40S AS 850HPA TEMPS STRUGGLE TO REACH 5C.
MODELS ARE CONSISTENT WITH KEEPING THE STRATUS FARTHER EAST...AND
HIGHS WILL STAY IN THE LOWER TO MID 30S. NOT LOOKING AT A DRIZZLE
THREAT AS FORECAST SOUNDINGS INDICATE RELATIVELY DRIER AIR RIGHT AT
THE SURFACE...TOO THIN OF A MOISTURE BAND...AND NO LIFT IN THE
NEAR SURFACE CLOUD LAYER.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 307 PM CST THU DEC 18 2014

MID RANGE...FRIDAY NIGHT THROUGH SUNDAY...IN THE MID
RANGE PERIODS...THE MAIN FORECAST CHALLENGE IS TEMPERATURES. FOR
FRIDAY NIGHT...BOTH THE LATEST NAM AND GFS SOLNS POSITION THE
WESTERN EDGE OF THE STRATUS DECK FROM SARGENT UP TO NAPER AT 00Z
SATURDAY. BY 12Z SATURDAY...THIS LINE EXTENDS ROUGHLY ALONG THE FAR
NERN BORDER OF THE FORECAST AREA. AS HAS BEEN THE CASE OVER THE PAST
COUPLE OF NIGHTS...THE WESTERN FRINGES OF THE STRATUS DECK IS WHERE
FOG WAS MOST PREVALENT. WITH LIGHT WINDS EXPECTED FRIDAY
NIGHT...DECIDED TO INSERT SOME PATCHY FOG ACROSS OUR FAR
NORTHEASTERN 4 COUNTIES. ELSEWHERE...CLEAR SKIES AND COLD TEMPS ARE
EXPECTED. WITH THE LIGHT WEST NORTHWESTERLY WINDS FORECAST ACROSS
SWRN NEBRASKA...DECIDED TO GO WITH SLIGHTLY COLDER LOWS IN THE
PLATTE RIVER VALLEY. ON SATURDAY...A WEAK SURFACE TROUGH WILL PUSH
EAST INTO THE CENTRAL SANDHILLS AND NORTH CENTRAL NEBRASKA. WITH
MOSTLY CLEAR SKIES...LIGHT WESTERLY WINDS AND H85 TEMPS IN THE LOW
SINGLE DIGITS ABOVE ZERO...HIGHS WILL REACH THE LOWER 40S...WITH
SOME MID AND UPPER 30S IN THE FAR NORTHEAST...WHERE STRATUS AND FOG
WILL BE POSSIBLE SATURDAY MORNING. FOR SATURDAY NIGHT AND
SUNDAY...LIGHT WESTERLY WINDS AND MOSTLY CLEAR SKIES ARE EXPECTED.
WITH THE EXCEPTION OF THE VALLEYS...WESTERLY WINDS SHOULD KEEP THE
BL SOMEWHAT MIXED SAT NIGHT. THIS WILL RESULT IN LOWS IN THE LOWER
20S WITH SOME TEENS POSSIBLE IN THE PLATTE VALLEY. SUNDAY WILL BE
THE WARMEST DAY OF THE PERIOD. WESTERLY WINDS WILL INCREASE AHEAD OF
AN APPROACHING COLD FRONT. SOUTH OF THE FRONT...H85 TEMPS WILL
INCREASE TO 3 TO 7C SUNDAY AFTERNOON...EQUATING TO HIGHS IN THE 40S
AND LOWER 50S. DECIDED TO UNDER CUT THIS A TAD BASED ON EXPECTED
RESIDUAL SNOW COVER AND THE THREAT FOR MID AND HIGH LEVEL CLOUDINESS
AS INDICATED IN THE GFS AND NAM H700-H500 RH PROGS.

SUNDAY NIGHT THROUGH CHRISTMAS DAY...FOR THE EXTENDED
PERIODS...PRECIPITATION CHANCES MONDAY-MONDAY NIGHT...FOLLOWED BY
PRECIPITATION CHANCES CHRISTMAS EVE NIGHT AND CHRISTMAS DAY WILL
HIGHLIGHT THE EXTENDED PERIODS. FOR MONDAY-MONDAY NIGHT...AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL DROP SOUTH FROM THE EASTERN
DAKOTAS INTO THE UPPER MIDWEST. AT THE SAME TIME ANOTHER...SEPARATE
UPPER LEVEL DISTURBANCE WILL DROP SOUTH ACROSS THE NORTHERN AND
CENTRAL ROCKIES. WITH BOTH THE GFS AND ECMWF SOLNS...SUFFICIENT LIFT
AND MOISTURE EXISTS WITH BOTH SYSTEMS TO PRODUCE PRECIPITATION.
ATTM...FEEL MORE CONFIDENT IN PRECIP CHANCES IN NORTHERN AND
NORTHEASTERN NEBRASKA IN ASSOCIATION WITH THE FIRST DISTURBANCE
MENTIONED ABOVE. ATTM THERE ARE SOME SUBTLE DIFFERENCES WITH THE
UPPER LEVEL JET STRUCTURE WITH THE WESTERN DISTURBANCE. THE ECMWF IS SLIGHTLY
FURTHER WEST WITH THE JET COMPARED TO THE GFS SOLN MONDAY...WHICH
FAVORS PRECIPITATION OVER THE ROCKIES VS. THE NEBR PANHANDLE AND FAR
SWRN CWA. ON TUESDAY AND THE FIRST HALF OF WEDNESDAY...THE FORECAST
AREA WILL BE BETWEEN SYSTEMS WITH MAINLY DRY CONDS EXPECTED. BY
MIDWEEK...A STRONG UPPER LEVEL TROUGH WILL DROP SOUTH INTO
IDAHO...UTAH AND NEVADA. THIS FEATURE WILL MIGRATE TO THE EAST
SOUTHEAST ON CHRISTMAS DAY. INCREASED MID LEVEL FRONTOGENESIS WILL
DEVELOP BEHIND AN EXITING ARCTIC FRONT CHRISTMAS DAY...WHICH WILL
LEAD TO INCREASED CHANCES FOR SNOW ACROSS THE FORECAST AREA. WITH
GOOD MODEL AGREEMENT NEXT WEEK...CONFIDENCE CONTINUES TO INCREASE IN
PRECIP CHANCES FOR CHRISTMAS DAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1122 PM CST THU DEC 18 2014

LIFR IS EXPECTED THROUGH AT LEAST 10Z AT KLBF. THE MODELS SHOW A
SLUG OF DRY AIR ALOFT MOVING THROUGH THIS AREA. THE RAP AND HRRR
SHOW THE FOG EXITING KLBF AROUND 15Z. THE NAM IS A BIT QUICKER.
THIS CONDITIONS WILL BE FAVORABLE FOR LIFR THROUGH 10Z BUT FLIGHT
CONDITIONS MAY IMPROVE 10Z-14Z...SOONER THAN FORECAST.

VFR IS EXPECTED ELSEWHERE OVERNIGHT AND FRIDAY EXCEPT ALONG AND
EAST OF A LINE FROM KANW-KLBF WHERE MVFR/LOCAL LIFR WILL CONTINUE
THROUGH 21Z. THIS AREA OF LOW CLOUDS AND FOG SHIFTS SLOWLY EAST
FRIDAY.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...CLB
SHORT TERM...DS
LONG TERM...CLB
AVIATION...CDC






AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 1252 AM EST FRI DEC 19 2014

.SYNOPSIS...
BROAD CYCLONIC CIRCULATION SURROUNDING SLOW-MOVING LOW PRESSURE
OVER THE CANADIAN MARITIMES WILL MAINTAIN CLOUDY SKIES AND A FEW
MOUNTAIN SNOW SHOWERS TONIGHT. HIGH PRESSURE BUILDS ACROSS THE
NORTH COUNTRY FRIDAY AND THROUGH THE WEEKEND...BRINGING GENERALLY
DRY WEATHER CONDITIONS...THOUGH SKIES WILL REMAIN VARIABLY CLOUDY
OWING TO LOW STRATUS. THE NEXT SIGNIFICANT STORM SYSTEM ARRIVES
FOR CHRISTMAS EVE WITH VERY WINDY AND MILD CONDITIONS...WITH
PERIODS OF MODERATE TO BRIEFLY HEAVY RAIN. BRISK AND SOMEWHAT
COLDER CONDITIONS ARE EXPECTED FOR CHRISTMAS DAY...WITH A
TRANSITION TO SNOW SHOWERS POSSIBLE...ESPECIALLY OVER THE HIGHER
TERRAIN.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 1221 AM EST FRIDAY...NO SIGNIFICANT ADJUSTMENTS FOR 1230
UPDATE. PATCHY -FZDZ HAS MATERIALIZED ACROSS PORTIONS OF NRN NY
AND CENTRAL/NRN VT OVER THE PAST 3 HOURS AS PRIMARY DENDRITIC SNOW
GROWTH LAYERS ARE TRENDING UNSATURATED. THIS HAS BEEN PICKED UP
QUITE WELL ON THIS EVENING`S RAP SOUNDING PROFILES AND HAVE ISSUED
SPECIAL WEATHER STATEMENTS TO HIGHLIGHT POTENTIAL LIGHT GLAZE
ICING ON UNTREATED/ELEVATED SURFACES OVERNIGHT. OTHERWISE FORECAST
REMAINS IN GOOD SHAPE AS BLOCKED MOIST NORTHWESTERLY FLOW
CONTINUES ACROSS THE AREA. OTHER THAN THE PATCHY -FZDZ AND SOME
PASSING FLURRIES/LIGHT SHSN ACTIVITY OVERNIGHT...A GENERALLY
CLOUDY NIGHT IS EXPECTED AS TEMPERATURES SETTLE INTO THE LOWER AND
MID 20S BY SUNRISE FRIDAY. HAVE A GREAT NIGHT.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 230 PM EST THURSDAY...RELATIVELY TRANQUIL SHORT-TERM
PERIOD...ONLY ISSUE WILL BE EXTENT OF STRATUS AND ASSOCIATED
IMPACT ON RADIATIVE HEATING/COOLING AND TEMPERATURES. HIGH
PRESSURE CENTERED ACROSS THE GREAT LAKES FRIDAY DRIFTS ACROSS THE
NERN CONUS AND SERN CANADA SATURDAY AND SATURDAY NIGHT. THIS WILL
BRING LIGHT WINDS...ESPECIALLY ON SATURDAY. 12Z NAM HAS TRENDED
TOWARD HIGHER LOW-LEVEL RH FOR FRIDAY. WITH WEAK WIND FIELDS AND
LOW-LEVEL INVERSION LAYER/LOW SUN ANGLE...WILL KEEP ANY PARTIAL
CLEARING FAIRLY LIMITED. SATURDAY WILL FEATURE PARTLY SUNNY
CONDITIONS...BUT AGAIN WITH AREAS OF STRATUS LIKELY HOLDING ON
ESPECIALLY CENTRAL/ERN VT. HAVE STAYED NEAR MOS CONSENSUS ON HIGH
TEMPERATURES...AND TRENDED ABOVE MOS CONSENSUS ON LOW TEMPS DUE TO
POTENTIAL CLOUDINESS DURING FRIDAY AND SATURDAY NIGHT.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 228 PM EST THURSDAY...MODEL GUIDANCE CONTINUES TO SHOW
SURFACE HIGH PRESSURE ON SUNDAY WITH SHORTWAVE ENERGY MOVING
THROUGH THE AREA, INCREASING CLOUDS ACROSS THE NORTH COUNTRY. THE
SURFACE HIGH SHIFTS NORTHEASTWARD OVER THE CANADIAN MARITIMES,
WHICH WILL PUT THE NORTH COUNTRY IN SOUTH TO SOUTHWEST FLOW,
COINCIDING WITH SOME UPPER LEVEL RIDGING. THIS WILL RESULT IN
WARMING TEMPERATURES FROM MAXES OF MID TO UPPER 20S TO END THE
WEEKEND, TO LOW TO MID 30S TO BEGIN THE WORK WEEK.

AS A LARGE DEEPENING UPPER LEVEL TROUGH STRETCHES SOUTHWARD
ACROSS THE PLAINS, EDGING INTO THE TEXARKANA REGION, A WAVE AHEAD
OF THIS MAIN TROUGH WILL INCREASE THE THREAT OF SNOW SHOWERS
TRANSITIONING RAIN SHOWERS IN THE VALLEYS AS WE RESIDE IN THE WARM
SECTOR MONDAY NIGHT INTO TUESDAY. THE THREAT FOR HEAVIER/MORE
SIGNIFICANT PRECIPITATION INCREASES WEDNESDAY INTO WEDNESDAY NIGHT
AS THE UPPER TROUGH BECOMES NEGATIVELY TILTED AND THE ASSOCIATED
SFC LOW STRENGTHENS QUICKLY. TRACK OF UPPER LEVEL FEATURES AND
SURFACE FEATURES STILL UNDER DEBATE AMONG THE MODELS, BUT STRONG
WINDS ARE ASSOCIATED WITH THIS SYSTEM ARE PRESENT IN GFS AND
ECMWF...WITH 850 MB WINDS EXCEEDING 55 KTS. GFS BEING STRONGER AND
850MB WINDS EXCEED 65KTS IN AREAS. THIS MAY BE PROBLEMATIC ACROSS
THE SUMMITS AND NWRN SLOPES. THIS WILL BE A STORM TO KEEP AN EYE
ON AS IT DEVELOPS AND TRACKS TOWARD THE NE USA.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...PERSISTENT STRATUS DECK WILL BRING
PREDOMINANTLY MVFR CONDITIONS TO THE REGION THROUGH THE PERIOD.
PERIODS OF IFR ALSO EXPECTED AT MPV/SLK TONIGHT AND CONTINUING AT
SLK ON FRIDAY. PBG IS THE ONLY EXCEPTION WHERE SOME LOCAL
DOWNSLOPING HAS ALLOWED CEILINGS TO LIFT TO VFR AND THAT IS ALSO
EXPECTED TO CONTINUE THROUGH FRIDAY. SOME LIGHT SNOW SHOWERS
REMAIN AT BTV/SLK/MPV...AND WILL LIKELY CONTINUE THROUGH AT LEAST
12Z...POSSIBLY LASTING TO 15Z AT MPV/SLK. HOWEVER ANY SNOW SHOWERS
WILL BE LIGHT WITH ONLY MINOR VISIBILITY REDUCTIONS EXPECTED...IF
ANY AT ALL. COULD ALSO BE A FEW BRIEF PERIODS OF FREEZING DRIZZLE
AT SAME SITES OVERNIGHT.

NORTHWEST WINDS FROM 5 TO 10 KNOTS WILL CONTINUE OVERNIGHT AND
FRIDAY...EXCEPT LOCALLY WEST/SOUTHWEST AT MSS/SLK.

OUTLOOK 06Z SATURDAY THROUGH TUESDAY...

06Z SAT-00Z SUN...IMPROVING CONDITIONS...BUT CHANCE OF LINGERING
STRATUS IN SOME AREAS BRINGING PERIODS OF MVFR.

00Z SUN-00Z TUE...VFR UNDER HIGH PRESSURE.

00Z TUE-00Z WED...PERIODS OF MVFR IN LIGHT MIXED PRECIPITATION.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...JMG/NEILES
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...RJS/MUCCILLI



AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 1224 AM EST FRI DEC 19 2014

.SYNOPSIS...
BROAD CYCLONIC CIRCULATION SURROUNDING SLOW-MOVING LOW PRESSURE
OVER THE CANADIAN MARITIMES WILL MAINTAIN CLOUDY SKIES AND A FEW
MOUNTAIN SNOW SHOWERS TONIGHT. HIGH PRESSURE BUILDS ACROSS THE
NORTH COUNTRY FRIDAY AND THROUGH THE WEEKEND...BRINGING GENERALLY
DRY WEATHER CONDITIONS...THOUGH SKIES WILL REMAIN VARIABLY CLOUDY
OWING TO LOW STRATUS. THE NEXT SIGNIFICANT STORM SYSTEM ARRIVES
FOR CHRISTMAS EVE WITH VERY WINDY AND MILD CONDITIONS...WITH
PERIODS OF MODERATE TO BRIEFLY HEAVY RAIN. BRISK AND SOMEWHAT
COLDER CONDITIONS ARE EXPECTED FOR CHRISTMAS DAY...WITH A
TRANSITION TO SNOW SHOWERS POSSIBLE...ESPECIALLY OVER THE HIGHER
TERRAIN.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 1221 AM EST FRIDAY...NO SIGNIFICANT ADJUSTMENTS FOR 1230
UPDATE. PATCHY -FZDZ HAS MATERIALIZED ACROSS PORTIONS OF NRN NY
AND CENTRAL/NRN VT OVER THE PAST 3 HOURS AS PRIMARY DENDRITIC SNOW
GROWTH LAYERS ARE TRENDING UNSATURATED. THIS HAS BEEN PICKED UP
QUITE WELL ON THIS EVENING`S RAP SOUNDING PROFILES AND HAVE ISSUED
SPECIAL WEATHER STATEMENTS TO HIGHLIGHT POTENTIAL LIGHT GLAZE
ICING ON UNTREATED/ELEVATED SURFACES OVERNIGHT. OTHERWISE FORECAST
REMAINS IN GOOD SHAPE AS BLOCKED MOIST NORTHWESTERLY FLOW
CONTINUES ACROSS THE AREA. OTHER THAN THE PATCHY -FZDZ AND SOME
PASSING FLURRIES/LIGHT SHSN ACTIVITY OVERNIGHT...A GENERALLY
CLOUDY NIGHT IS EXPECTED AS TEMPERATURES SETTLE INTO THE LOWER AND
MID 20S BY SUNRISE FRIDAY. HAVE A GREAT NIGHT.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 230 PM EST THURSDAY...RELATIVELY TRANQUIL SHORT-TERM
PERIOD...ONLY ISSUE WILL BE EXTENT OF STRATUS AND ASSOCIATED
IMPACT ON RADIATIVE HEATING/COOLING AND TEMPERATURES. HIGH
PRESSURE CENTERED ACROSS THE GREAT LAKES FRIDAY DRIFTS ACROSS THE
NERN CONUS AND SERN CANADA SATURDAY AND SATURDAY NIGHT. THIS WILL
BRING LIGHT WINDS...ESPECIALLY ON SATURDAY. 12Z NAM HAS TRENDED
TOWARD HIGHER LOW-LEVEL RH FOR FRIDAY. WITH WEAK WIND FIELDS AND
LOW-LEVEL INVERSION LAYER/LOW SUN ANGLE...WILL KEEP ANY PARTIAL
CLEARING FAIRLY LIMITED. SATURDAY WILL FEATURE PARTLY SUNNY
CONDITIONS...BUT AGAIN WITH AREAS OF STRATUS LIKELY HOLDING ON
ESPECIALLY CENTRAL/ERN VT. HAVE STAYED NEAR MOS CONSENSUS ON HIGH
TEMPERATURES...AND TRENDED ABOVE MOS CONSENSUS ON LOW TEMPS DUE TO
POTENTIAL CLOUDINESS DURING FRIDAY AND SATURDAY NIGHT.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 228 PM EST THURSDAY...MODEL GUIDANCE CONTINUES TO SHOW
SURFACE HIGH PRESSURE ON SUNDAY WITH SHORTWAVE ENERGY MOVING
THROUGH THE AREA, INCREASING CLOUDS ACROSS THE NORTH COUNTRY. THE
SURFACE HIGH SHIFTS NORTHEASTWARD OVER THE CANADIAN MARITIMES,
WHICH WILL PUT THE NORTH COUNTRY IN SOUTH TO SOUTHWEST FLOW,
COINCIDING WITH SOME UPPER LEVEL RIDGING. THIS WILL RESULT IN
WARMING TEMPERATURES FROM MAXES OF MID TO UPPER 20S TO END THE
WEEKEND, TO LOW TO MID 30S TO BEGIN THE WORK WEEK.

AS A LARGE DEEPENING UPPER LEVEL TROUGH STRETCHES SOUTHWARD
ACROSS THE PLAINS, EDGING INTO THE TEXARKANA REGION, A WAVE AHEAD
OF THIS MAIN TROUGH WILL INCREASE THE THREAT OF SNOW SHOWERS
TRANSITIONING RAIN SHOWERS IN THE VALLEYS AS WE RESIDE IN THE WARM
SECTOR MONDAY NIGHT INTO TUESDAY. THE THREAT FOR HEAVIER/MORE
SIGNIFICANT PRECIPITATION INCREASES WEDNESDAY INTO WEDNESDAY NIGHT
AS THE UPPER TROUGH BECOMES NEGATIVELY TILTED AND THE ASSOCIATED
SFC LOW STRENGTHENS QUICKLY. TRACK OF UPPER LEVEL FEATURES AND
SURFACE FEATURES STILL UNDER DEBATE AMONG THE MODELS, BUT STRONG
WINDS ARE ASSOCIATED WITH THIS SYSTEM ARE PRESENT IN GFS AND
ECMWF...WITH 850 MB WINDS EXCEEDING 55 KTS. GFS BEING STRONGER AND
850MB WINDS EXCEED 65KTS IN AREAS. THIS MAY BE PROBLEMATIC ACROSS
THE SUMMITS AND NWRN SLOPES. THIS WILL BE A STORM TO KEEP AN EYE
ON AS IT DEVELOPS AND TRACKS TOWARD THE NE USA.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THROUGH 00Z SATURDAY...PERSISTENT STRATUS DECK WILL BRING
PREDOMINANTLY MVFR CONDITIONS TO THE REGION THROUGH THE PERIOD.
WIDESPREAD MVFR CONDITIONS EXIST THIS EVENING AND WILL CONTINUE
THROUGH TONIGHT AND ON FRIDAY. PERIODS OF IFR ALSO EXPECTED AT
MPV/SLK TONIGHT AND CONTINUING AT SLK FOR FRIDAY. PBG IS THE ONLY
EXCEPTION WHERE SOME LOCAL DOWNSLOPING HAS ALLOWED CEILINGS TO
LIFT TO VFR THIS EVENING AND THAT IS ALSO EXPECTED TO CONTINUE
THROUGH FRIDAY. SOME LIGHT SNOW SHOWERS REMAIN AT
BTV/SLK/MPV...AND WILL LIKELY CONTINUE THROUGH AT LEAST
06Z...POSSIBLY LASTING TO 12Z AT MPV/SLK. HOWEVER ANY SNOW SHOWERS
WILL BE LIGHT WITH ONLY MINOR VISIBILITY REDUCTIONS EXPECTED...IF
ANY AT ALL.

NORTHWEST WINDS FROM 5 TO 10 KNOTS WILL CONTINUE THROUGH TONIGHT
AND FRIDAY...EXCEPT LOCALLY WEST/SOUTHWEST AT MSS/SLK.

OUTLOOK 00Z SATURDAY THROUGH TUESDAY...

00Z SAT-00Z SUN...IMPROVING CONDITIONS...BUT CHANCE OF LINGERING
STRATUS IN SOME AREAS BRINGING PERIODS OF MVFR.

00Z SUN-00Z TUE...VFR UNDER HIGH PRESSURE.

00Z TUE-00Z WED...PERIODS OF MVFR IN LIGHT MIXED PRECIPITATION.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...JMG/NEILES
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...MUCCILLI



AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 943 PM EST SAT DEC 20 2014

.SYNOPSIS...
WEAK HIGH PRESSURE ALONG WITH A FRONT JUST OFFSHORE WILL KEEP CLOUDY
AND COOL CONDITIONS IN PLACE THROUGH SUNDAY. ANOTHER ROUND OF RAIN
IS EXPECTED...ESPECIALLY LATE SUNDAY INTO MONDAY WHEN A STORM MOVES
UP THE COAST. SHOWERS AND THUNDERSTORMS RETURN TUESDAY NIGHT INTO
WEDNESDAY WITH A COLD FRONT. BREEZY BUT CLEAR WEATHER IS EXPECTED
FOR CHRISTMAS DAY. DRY CONDITIONS WILL PERSIST INTO NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 940 PM SATURDAY...SHORTWAVE ACROSS WEST TEXAS IS ENABLING THE
SOUTHERN STREAM TO BUCKLE INTO THE SOUTHERN STATES THIS EVENING.
THUS THE SWATH OF MID LEVEL DRY AIR CURRENTLY ACROSS THE CAROLINAS
WILL BE SHORT-LIVED. REGIONAL RADAR SHOWS LIGHT RAIN ACROSS PORTIONS
OF SOUTHERN SC AND SOUTHEASTERN GA...MOVING E-NE. THINK MOST OF THIS
VERY LOW QPF RAINFALL WILL REMAIN TO OUR SOUTH TONIGHT. ISENTROPIC
LIFT DOESN`T RETURN IN EARNEST ACROSS OUR AREA UNTIL SUNDAY. HAVE
HEDGE POPS UPWARD ACROSS THE SOUTHERN ZONES BY 1200 UTC SUN.
OTHERWISE WITH WEAK COLD AIR ADVECTION AT THE SURFACE AND AMPLE
CLOUD COVER TEMPS WILL ONLY SLOWLY DROP THROUGH THE EARLY MORNING
HOURS. BUMPED UP MINS A FEW DEGREES GIVEN THIS TREND... ESPECIALLY
ACROSS THE PEE DEE AND LBT AREA WHERE TEMPS ARE STILL HANGING ON IN
THE LOWER 40S. PATCHY FOG IS ALSO A GOOD BET THROUGH THE OVERNIGHT.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 330 PM SATURDAY...DREARY CONDITIONS WILL CONTINUE FOR THE
SHORT TERM PERIOD. A BROAD SOUTHWEST FLOW ALOFT WILL INTERACT WITH A
PERSISTENT BAROCLINIC ZONE JUST OFFSHORE AND A WEDGE OF HIGH
PRESSURE INLAND. THE MODELS ARE IN GENERAL AGREEMENT ON SUNDAY
REMAINING DRY FOR THE MOST PART. THERE COULD BE THE ISOLATED
SPRINKLE OR MORE LIKELY PATCH OF DRIZZLE BUT OVERCAST SKIES AND COOL
CONDITIONS SHOULD DO IT.

A 300MB JET STREAK BRINGS ANOTHER ROUND OF RAIN FOR LATE SUNDAY INTO
MONDAY MORNING. THE NAM AND GFS PAINT MOST OF THE HEAVIER QPF
OFFSHORE WHERE THE BEST DIVERGENCE ALOFT RESIDES. THE BEST
ISENTROPIC LIFT ON THE 300K SURFACE RESIDES WEST OF I-95 AND THE
COAST IS LEFT IN BETWEEN WITH WEAK FORCING. HOWEVER THE QPF AMOUNTS
WEST OF THE INTERSTATE ARE CERTAINLY NOT IMPRESSIVE MAKING THE
OVERALL QPF AMOUNTS FAIRLY PALTRY. BEYOND MONDAY MORNING THE BEST
FORCING MOVES OFF QUICKLY LEAVING OVERCAST/DRIZZLY SKIES.

TEMPERATURE GUIDANCE IS IN GENERAL AGREEMENT OTHER THAN MONDAYS
HIGHS WHEN THE GFS/MAV NUMBERS ARE MUCH WARMER. HARD TO TRUST THESE
HOWEVER AS SURFACE PRESSURE PLOTS SHOW THE WEDGE...ALTHOUGH
WEAKENING REMAINING IN PLACE. I DID USE A BLEND BUT WOULD NOT BE
SURPRISED TO SEE SUBSEQUENT BULLETINS FROM THE GFS COOL.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 PM SATURDAY...WEDGE WILL BE ERODED ON TUES AS A WAVE OF
LOW PRESSURE MOVES NORTH ALONG THE CAROLINA COAST. AT THE SAME TIME
A HIGH AMPLITUDE MID TO UPPER TROUGH WILL DIG DOWN FROM THE UPPER
GREAT LAKES INTO TEXAS PUSHING A COLD FRONT EAST. A DEEP S-SW FLOW
WILL BRING PLENTY OF WARM AIR AND MOISTURE INTO THE SOUTHEAST AHEAD
OF THE FRONT. INITIALLY ON TUES SHALLOW COOLER AIR WILL BE IN PLACE
AS THE WARMER AIR OVERRIDES IT PRODUCING INCREASED ISENTROPIC LIFT
AND INCREASED RAIN CHANCES. AS THE DAY WEARS ON...THE WINDS WILL
COME AROUND WITH WARMER AND MOISTER AIR FLOWING IN. ALWAYS TOUGH TO
TIME THIS AS COLD DENSE AIR HOLDS ON LONGER THAN MODELS USUALLY
PREDICT. FOR NOW WILL KEEP WITH TEMPS WARMING THROUGH LATE DAY WITH
WARMER AND MORE HUMID AIR MASS IN PLACE TUES NIGHT INTO WED.

UNSETTLED WEATHER WILL REMAIN AHEAD THE COLD FRONT THROUGH TUES
NIGHT INTO WED BEFORE COLD FRONT MOVES THROUGH LATE WED. INCREASING
LOW LEVEL JET UP TO 40 KTS WILL COMBINE WITH BETTER UPPER LEVEL
FORCING TO PRODUCE MORE WIDESPREAD SHOWERS THROUGH TUES NIGHT INTO
WED. KEPT ISOLATED THUNDERSTORMS IN FORECAST TUES NIGHT INTO WED AS
WARM FRONT LIFTS NORTH AND LOCAL AREA GETS INTO BEST MOISTURE AND
LIFT. PCP WATER VALUES REACH UP TO 2 INCHES ALONG THE COAST WED AFTN

THE DIGGING MID TO UPPER TROUGH WILL PUSH THE COLD FRONT THROUGH WED
NIGHT BEFORE FINALLY MOVE OFF SHORE BY THURS MORNING LEAVING DRIER
AND COOLER WEATHER FOR CHRISTMAS DAY. OVERALL EXPECT CLOUDY AND DAMP
TO WET WEATHER THROUGH THE FIRST HALF OF THE PERIOD WITH COOLER MORE
SEASONABLE WEATHER THURS INTO FRI AS HIGH PRESSURE BUILDS ACROSS THE
SOUTH. THE HIGH WILL SHIFT OFF SHORE THROUGH FRI LEAVING A LIGHT
RETURN FLOW AND WARMER TEMPS FRI INTO SATURDAY WITH A GOOD DEAL OF
SUNSHINE. NEXT COLD FRONT SHOULD MOVE THROUGH SAT NIGHT BUT LOOKS
LIKE IT MAY BE LACKING ANY DEEP MOISTURE.


&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CIGS WILL LIKELY BOUNCE AROUND BETWEEN MVFR/VFR LEVELS
OVERNIGHT AND INTO SUNDAY AS WE ENTER A PERIOD OF UNSETTLED WEATHER.
FCST SOUNDINGS REMAIN SATURATED IN THE 3-10KFT LAYER THROUGH MUCH OF
THE PERIOD. WILL MAINTAIN MVFR CIGS THROUGH TONIGHT...LOWEST AT THE
COASTAL TERMINALS. THERE HAVE BEEN PATCHES OF STRATUS AROUND 1KFT
REPORTED ALONG THE COAST THIS EVENING...BUT DO NOT ANTICIPATE ANY
PERSISTENT IFR CIGS TONIGHT AS FCST SOUNDINGS NEVER COMPLETELY LOCK
IN THIS LOW LEVEL MOISTURE. THE LATEST HRRR AND SREF CIG PROBS ALSO
SUPPORT KEEPING IFR OUT OF THE TAFS ATTM. IN FACT...CIGS SHOULD
GRADUALLY LIFT TOWARD DAYBREAK IF THE CURRENT GUIDANCE TRENDS ARE
CORRECT. NORTHEAST WINDS AOB 10 KT WILL PERSIST THROUGH THE DAY
SUNDAY. ANOTHER ROUND OF MOIST ISENTROPIC LIFT WILL BRING MORE
-RA/DZ TO THE AREA DURING THE DAY...SPREADING FROM SOUTH TO NORTH
BEGINNING AROUND 15Z AT THE SOUTHERN TERMINALS AND AFTER 18Z AT
KILM/KLBT. THIS SHOULD AGAIN HELP LOWER CIGS TO MVFR LEVELS THROUGH
THE AFTERNOON.

EXTENDED OUTLOOK...RAIN LIKELY MON WITH MVFR/IFR CIGS AS A COASTAL
TROUGH DEVELOPS OFFSHORE. SHOWERS/TEMPO MVFR EXPECTED TUE/WED AHEAD
OF A STRONG COLD FRONT. GUSTY WINDS WED/THU BEFORE AND AFTER FROPA.
THU WILL BE VFR AT ALL TERMINALS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 940 PM SATURDAY...NORTH TO NORTHEAST FETCH WITH LOW PRESSURE
TO THE SOUTH AND RIDGING FROM THE NORTH HAS RESULTED IN STEEP 3 TO 5
FT. THE DOMINANT PERIOD IS AROUND 5 SECONDS THIS EVENING...AND A
SIMILAR SEA STATE IS EXPECTED OVERNIGHT. FIRST BATCH OF LIGHT RAIN
IS EXITING THE CAPE FEAR COASTAL WATERS. TRENDS FOR INCREASING LIGHT
RAIN...ESPECIALLY SOUTHERN WATERS...DURING THE EARLY MORNING HOURS.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 330 PM SATURDAY...A FAIRLY BRISK NORTHEAST FLOW WILL PERSIST
ACROSS THE COASTAL WATERS SUNDAY IN BETWEEN A BAROCLINIC ZONE TO THE
EAST AND HIGH PRESSURE INLAND. AS LOW PRESSURE DEVELOPS AND MOVES UP
ALONG THIS FRONT SUNDAY NIGHT...THE FLOW WILL TURN MORE EASTERLY.
SPEEDS THROUGHOUT WILL BE 15-20 KNOTS. SOME HIGHER SEAS CAN BE
EXPECTED WITH THE SOMEWHAT PROLONGED NATURE OF THE WINDS...3-5 FEET.
CANT RULE OUT A FEW SIX FOOTERS BUT THINK A SMALL CRAFT HEADLINE CAN
BE AVOIDED. LIGHTER WINDS AND SEAS CAN BE EXPECTED MONDAY ALTHOUGH
THE FLOW WILL GENERALLY BE THE SAME.

LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 330 PM SATURDAY...WAVE OF LOW PRESSURE WILL MOVE UP THE
CAROLINA COAST ON TUES WITH WINDS COMING AROUND THROUGH THE DAY.
LIGHT NORTHERLY WINDS WILL SHIFT AROUND BECOMING MORE ON SHORE
THROUGH THE DAY AND EVENTUALLY SOUTHERLY BY TUES EVENING.

A LARGE AND POTENT STORM SYSTEM WILL PUSH A COLD FRONT EAST WITH
INCREASING SOUTHERLY WINDS IN A TIGHTENING GRADIENT FLOW TUES NIGHT
INTO WED. WINDS WILL INCREASE UP TO 15 TO 25 KTS TUES NIGHT INTO WED
AHEAD OF THE COLD FRONT. THIS WILL PUSH SEAS UP FROM 2 TO 4 FT EARLY
TUES TO 3 TO 5 FT BY LATE TUES. WNA SHOWS SEAS RAMPING UP ABOVE 6 FT
BY WED MORNING AND POSSIBLE UP TO 7 TO 9 FT IN OUTER WATERS IN
STRONGER SW TO W FLOW AS FRONT MOVES THROUGH THE WATERS LATE WED
INTO WED NIGHT. EXPECT SMALL CRAFT CONDITIONS WED AND LASTING INTO
THURS WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN STRONGER
W-NW FLOW BEHIND FRONT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...SRP
SHORT TERM...SHK
LONG TERM...RGZ
AVIATION...BJR






AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 631 PM EST SAT DEC 20 2014

.SYNOPSIS...
WEAK HIGH PRESSURE ALONG WITH A FRONT JUST OFFSHORE WILL KEEP CLOUDY
AND COOL CONDITIONS IN PLACE THROUGH SUNDAY. ANOTHER ROUND OF RAIN
IS EXPECTED EARLY MONDAY WHEN A STORM MOVES UP THE COAST. SHOWERS
AND THUNDERSTORMS RETURN TUESDAY NIGHT INTO WEDNESDAY WITH A COLD
FRONT. CLEAR WEATHER IS EXPECTED FOR CHRISTMAS DAY INTO NEXT
WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 615 PM SATURDAY...THE FIRST BATCH OF LIGHT RAIN HAS EXITED THE
COAST AS DRY MID-LEVEL AIR HAS SPREAD ACROSS MUCH OF THE CAROLINAS.
MAY NEED TO BUMP POPS UPWARD...ESPECIALLY ACROSS SC ZONES...AS NEXT
ROUND OF ISENTROPIC LIFT COMES INTO PLAY DURING THE EARLY MORNING
HOURS. THE REMAINDER OF THE FORECAST IS ON TRACK...WITH NO MAJOR
CHANGES.

PREVIOUS DISCUSSION...
AS OF 330 PM SATURDAY...REGIONAL RADAR AND SATELLITE SHOW BACK EDGE
OF PRECIP SHIELD ENTERING THE WESTERN EDGES OF THE FORECAST AREA.
DURING THE NEXT SEVERAL HOURS THIS DRYING WILL CONTINUE FROM WEST
TO EAST...REACHING THE COAST DURING THE LATE AFTERNOON/EARLY
EVENING TIME FRAME. THIS IS DOWN TO A SUBTLE BUT SIGNIFICANT SHIFT
IN THE WINDS IN THE 2-4K FT AS THE WEAK SURFACE LOW SLOWLY MOVES
AWAY FROM THE COAST. ALTHOUGH LOW LEVEL MOISTURE WILL LINGER
OVERNIGHT THE LAYER ABOVE 800 MB DRIES OUT IN PART DUE TO DEEP
WESTERLY FLOW. AT THE SURFACE THE WEDGE HOLDS ON WITH LOW LEVEL
NORTHEAST FLOW MAINTAINING A STRATUS DECK THROUGH THE END OF THE
PERIOD. ALTHOUGH MOISTURE BELOW 800 MB REMAINS ELEVATED FORECAST
SOUNDINGS DO NOT SHOW ANY LAYER AS BEING SATURATED. WILL NOT CARRY
ANY MENTION OF DRIZZLE BUT MAY MENTION FOG EARLY SUN MORNING.
BOUNDARY LAYER WINDS DO NOT GO CALM BUT THEY WILL BE LIGHT.
COMBINED WITH RECENT PRECIP THESE CONDITIONS COULD LEAD TO SOME
PATCHY FOG DEVELOPMENT THOUGH LOWEST VIS WOULD BE ON THE ORDER OF
3 OR 4 MILES...SO DO NOT ANTICIPATE ISSUANCE OF DFA. LOWS END UP A
LITTLE BELOW CLIMO...A COMBINATION OF HIGHS 10 DEGREES TODAY BELOW
CLIMO...LIGHT NORTHEAST FLOW AND SUBTLE COLD ADVECTION BEHIND THE
EXITING 5H SHORTWAVE.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...AS OF 330
PM SATURDAY...DREARY CONDITIONS WILL CONTINUE FOR THE SHORT TERM
PERIOD. A BROAD SOUTHWEST FLOW ALOFT WILL INTERACT WITH A PERSISTENT
BAROCLINIC ZONE JUST OFFSHORE AND A WEDGE OF HIGH PRESSURE INLAND.
THE MODELS ARE IN GENERAL AGREEMENT ON SUNDAY REMAINING DRY FOR THE
MOST PART. THERE COULD BE THE ISOLATED SPRINKLE OR MORE LIKELY PATCH
OF DRIZZLE BUT OVERCAST SKIES AND COOL CONDITIONS SHOULD DO IT.

A 300MB JET STREAK BRINGS ANOTHER ROUND OF RAIN FOR LATE SUNDAY INTO
MONDAY MORNING. THE NAM AND GFS PAINT MOST OF THE HEAVIER QPF
OFFSHORE WHERE THE BEST DIVERGENCE ALOFT RESIDES. THE BEST
ISENTROPIC LIFT ON THE 300K SURFACE RESIDES WEST OF I-95 AND THE
COAST IS LEFT IN BETWEEN WITH WEAK FORCING. HOWEVER THE QPF AMOUNTS
WEST OF THE INTERSTATE ARE CERTAINLY NOT IMPRESSIVE MAKING THE
OVERALL QPF AMOUNTS FAIRLY PALTRY. BEYOND MONDAY MORNING THE BEST
FORCING MOVES OFF QUICKLY LEAVING OVERCAST/DRIZZLY SKIES.

TEMPERATURE GUIDANCE IS IN GENERAL AGREEMENT OTHER THAN MONDAYS
HIGHS WHEN THE GFS/MAV NUMBERS ARE MUCH WARMER. HARD TO TRUST THESE
HOWEVER AS SURFACE PRESSURE PLOTS SHOW THE WEDGE...ALTHOUGH
WEAKENING REMAINING IN PLACE. I DID USE A BLEND BUT WOULD NOT BE
SURPRISED TO SEE SUBSEQUENT BULLETINS FROM THE GFS COOL.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 PM SATURDAY...WEDGE WILL BE ERODED ON TUES AS A WAVE OF
LOW PRESSURE MOVES NORTH ALONG THE CAROLINA COAST. AT THE SAME TIME
A HIGH AMPLITUDE MID TO UPPER TROUGH WILL DIG DOWN FROM THE UPPER
GREAT LAKES INTO TEXAS PUSHING A COLD FRONT EAST. A DEEP S-SW FLOW
WILL BRING PLENTY OF WARM AIR AND MOISTURE INTO THE SOUTHEAST AHEAD
OF THE FRONT. INITIALLY ON TUES SHALLOW COOLER AIR WILL BE IN PLACE
AS THE WARMER AIR OVERRIDES IT PRODUCING INCREASED ISENTROPIC LIFT
AND INCREASED RAIN CHANCES. AS THE DAY WEARS ON...THE WINDS WILL
COME AROUND WITH WARMER AND MOISTER AIR FLOWING IN. ALWAYS TOUGH TO
TIME THIS AS COLD DENSE AIR HOLDS ON LONGER THAN MODELS USUALLY
PREDICT. FOR NOW WILL KEEP WITH TEMPS WARMING THROUGH LATE DAY WITH
WARMER AND MORE HUMID AIR MASS IN PLACE TUES NIGHT INTO WED.

UNSETTLED WEATHER WILL REMAIN AHEAD THE COLD FRONT THROUGH TUES
NIGHT INTO WED BEFORE COLD FRONT MOVES THROUGH LATE WED. INCREASING
LOW LEVEL JET UP TO 40 KTS WILL COMBINE WITH BETTER UPPER LEVEL
FORCING TO PRODUCE MORE WIDESPREAD SHOWERS THROUGH TUES NIGHT INTO
WED. KEPT ISOLATED THUNDERSTORMS IN FORECAST TUES NIGHT INTO WED AS
WARM FRONT LIFTS NORTH AND LOCAL AREA GETS INTO BEST MOISTURE AND
LIFT. PCP WATER VALUES REACH UP TO 2 INCHES ALONG THE COAST WED AFTN

THE DIGGING MID TO UPPER TROUGH WILL PUSH THE COLD FRONT THROUGH WED
NIGHT BEFORE FINALLY MOVE OFF SHORE BY THURS MORNING LEAVING DRIER
AND COOLER WEATHER FOR CHRISTMAS DAY. OVERALL EXPECT CLOUDY AND DAMP
TO WET WEATHER THROUGH THE FIRST HALF OF THE PERIOD WITH COOLER MORE
SEASONABLE WEATHER THURS INTO FRI AS HIGH PRESSURE BUILDS ACROSS THE
SOUTH. THE HIGH WILL SHIFT OFF SHORE THROUGH FRI LEAVING A LIGHT
RETURN FLOW AND WARMER TEMPS FRI INTO SATURDAY WITH A GOOD DEAL OF
SUNSHINE. NEXT COLD FRONT SHOULD MOVE THROUGH SAT NIGHT BUT LOOKS
LIKE IT MAY BE LACKING ANY DEEP MOISTURE.


&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CIGS WILL LIKELY BOUNCE AROUND BETWEEN MVFR/VFR LEVELS
OVERNIGHT AND INTO SUNDAY AS WE ENTER A PERIOD OF UNSETTLED WEATHER.
FCST SOUNDINGS REMAIN SATURATED IN THE 3-10KFT LAYER THROUGH MUCH OF
THE PERIOD. WILL MAINTAIN MVFR CIGS THROUGH TONIGHT...LOWEST AT THE
COASTAL TERMINALS. THERE HAVE BEEN PATCHES OF STRATUS AROUND 1KFT
REPORTED ALONG THE COAST THIS EVENING...BUT DO NOT ANTICIPATE ANY
PERSISTENT IFR CIGS TONIGHT AS FCST SOUNDINGS NEVER COMPLETELY LOCK
IN THIS LOW LEVEL MOISTURE. THE LATEST HRRR AND SREF CIG PROBS ALSO
SUPPORT KEEPING IFR OUT OF THE TAFS ATTM. IN FACT...CIGS SHOULD
GRADUALLY LIFT TOWARD DAYBREAK IF THE CURRENT GUIDANCE TRENDS ARE
CORRECT. NORTHEAST WINDS AOB 10 KT WILL PERSIST THROUGH THE DAY
SUNDAY. ANOTHER ROUND OF MOIST ISENTROPIC LIFT WILL BRING MORE
-RA/DZ TO THE AREA DURING THE DAY...SPREADING FROM SOUTH TO NORTH
BEGINNING AROUND 15Z AT THE SOUTHERN TERMINALS AND AFTER 18Z AT
KILM/KLBT. THIS SHOULD AGAIN HELP LOWER CIGS TO MVFR LEVELS THROUGH
THE AFTERNOON.

EXTENDED OUTLOOK...RAIN LIKELY MON WITH MVFR/IFR CIGS AS A COASTAL
TROUGH DEVELOPS OFFSHORE. SHOWERS/TEMPO MVFR EXPECTED TUE/WED AHEAD
OF A STRONG COLD FRONT. GUSTY WINDS WED/THU BEFORE AND AFTER FROPA.
THU WILL BE VFR AT ALL TERMINALS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 615 PM SATURDAY...THE CURRENT FORECAST IS ON TRACK. NO MAJOR
CHANGES WERE MADE WITH THE LATEST CWF ISSUANCE.

PREVIOUS DISCUSSION...
AS OF 330 PM SATURDAY...NORTHEAST FLOW OF 10 TO 15 KT THIS AFTERNOON
AND OVERNIGHT MAY BRIEFLY JUMP INTO THE 15 TO 20 KT RANGE AS
GRADIENT TIGHTENS A BIT. EXIT OF SURFACE LOW TO THE EAST WILL BE
FOLLOWED BY HIGH REASSERTING ITSELF SO GRADIENT DOES NOT CHANGE A
LOT. 12 TO 18 HOUR PERIOD OF ENHANCED NORTHEAST FLOW WILL PUSH
SEAS...CURRENTLY RUNNING 2 TO 3 FT...TO 3 TO 5 FT THIS EVENING AND
OVERNIGHT. EXCEPTION WILL BE ALONG THE BRUNSWICK COAST WHERE
OFFSHORE FLOW WILL KEEP SEAS 1 TO 2 FT CLOSER TO SHORE.

ALTHOUGH CONDITIONS ARE LIKELY TO BE CLOSE TO SCEC ADVISORY DO NOT
PLAN TO RAISE ONE AT THIS TIME. MAINLY BECAUSE THE INCREASE IN
WIND SPEEDS SO FAR TODAY HAVE BEEN A LITTLE UNDER WHAT WAS
EXPECTED. GIVEN THE ALREADY MARGINAL NATURE OF THE EVENT WILL HOLD
OFF FOR NOW...THOUGH THE EVENING SHIFT MAY DECIDE TO RAISE ONE.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 330 PM SATURDAY...A FAIRLY BRISK NORTHEAST FLOW WILL PERSIST
ACROSS THE COASTAL WATERS SUNDAY IN BETWEEN A BAROCLINIC ZONE TO THE
EAST AND HIGH PRESSURE INLAND. AS LOW PRESSURE DEVELOPS AND MOVES UP
ALONG THIS FRONT SUNDAY NIGHT...THE FLOW WILL TURN MORE EASTERLY.
SPEEDS THROUGHOUT WILL BE 15-20 KNOTS. SOME HIGHER SEAS CAN BE
EXPECTED WITH THE SOMEWHAT PROLONGED NATURE OF THE WINDS...3-5 FEET.
CANT RULE OUT A FEW SIX FOOTERS BUT THINK A SMALL CRAFT HEADLINE CAN
BE AVOIDED. LIGHTER WINDS AND SEAS CAN BE EXPECTED MONDAY ALTHOUGH
THE FLOW WILL GENERALLY BE THE SAME.

LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 330 PM SATURDAY...WAVE OF LOW PRESSURE WILL MOVE UP THE
CAROLINA COAST ON TUES WITH WINDS COMING AROUND THROUGH THE DAY.
LIGHT NORTHERLY WINDS WILL SHIFT AROUND BECOMING MORE ON SHORE
THROUGH THE DAY AND EVENTUALLY SOUTHERLY BY TUES EVENING.

A LARGE AND POTENT STORM SYSTEM WILL PUSH A COLD FRONT EAST WITH
INCREASING SOUTHERLY WINDS IN A TIGHTENING GRADIENT FLOW TUES NIGHT
INTO WED. WINDS WILL INCREASE UP TO 15 TO 25 KTS TUES NIGHT INTO WED
AHEAD OF THE COLD FRONT. THIS WILL PUSH SEAS UP FROM 2 TO 4 FT EARLY
TUES TO 3 TO 5 FT BY LATE TUES. WNA SHOWS SEAS RAMPING UP ABOVE 6 FT
BY WED MORNING AND POSSIBLE UP TO 7 TO 9 FT IN OUTER WATERS IN
STRONGER SW TO W FLOW AS FRONT MOVES THROUGH THE WATERS LATE WED
INTO WED NIGHT. EXPECT SMALL CRAFT CONDITIONS WED AND LASTING INTO
THURS WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN STRONGER
W-NW FLOW BEHIND FRONT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...SHK
NEAR TERM...SRP
SHORT TERM...SHK
LONG TERM...RGZ
AVIATION...BJR









AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 950 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 948 PM CST SAT DEC 20 2014

NOT TOO UNEXPECTED AND HAS PREDICTED BY HRRR AND LOCAL WRF...BAND
OF SNOW INTENSIFED OVER PARTS OF THE NRN RRV AS IT SPREADS INTO NW
MN. UPPED POPS FOR NW MN TO ACCOUNT FOR UP TO 1 INCH OF SNOW.
OTHERWISE KEPT THE AREAS OF FOG AND ZL. NEXT ISSUE IS SEEING NEW
CONVECTIVE LOOKING SHOWERS NR COOPERSTOWN IN ADDITION TO STUFF
EAST OF MINOT. THAT WAS FZRA AT MINOT BUT FARTHER EAST A BIT
COOLER ALOFT SO MORE -SN. BUT WILL KEEP FZDZ AS WELL AS ENOUGH
WARM AIR ALOFT TO GIVE A MIX.


&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 310 PM CST SAT DEC 20 2014

FORECAST CHALLENGES WILL BE THE PCPN MOVING THROUGH THE FA TONIGHT
AND THEN THE POTENTIAL FOR A MON/TUE SNOWFALL. AS OF MID AFTERNOON
FOG STILL COVERED THE ENTIRE FA WITH A FEW PATCHES OF DENSE FOG
STILL UP AROUND CANDO/LANGDON. REGIONAL RADAR SHOWED A BAND OF
VERY LIGHT PCPN FROM BOTTINEAU DOWN THRU KJMS MOVING TO THE EAST
AT ABOUT 20KTS. KBIS DID GET A TRACE OF FZDZ AS THIS MOVED THRU
THEM AND NOW K06D IS REPORTING UNKNOWN PCPN. THINK THIS WILL
REMAIN PRETTY LIGHT FZDZ POSSIBLY MIXED WITH SOME LIGHT SNOW AS IT
MOVES THRU TONIGHT. AT THIS POINT THINK IT WILL STAY A THIN BAND
AS IT MOVES EAST THRU ND AND BE PRETTY MINIMAL. THERE IS ALSO SOME
COMMA HEAD PCPN MOVING INTO FAR NW ND NOW ASSOCIATED WITH THE MID
LEVEL WAVE. THEREFORE THERE COULD BE A LITTLE ADDITIONAL PCPN
ALONG THE CANADIAN BORDER LATER ASSOCIATED WITH THIS FEATURE.
MODELS SHOW THE THIN BAND POSSIBLY STRENGTHENING AS IT MOVES INTO
NW MN LATER THIS EVENING WITH A DUSTING TO AN INCH OF SNOW
POSSIBLE THERE. SINCE FOG STILL REMAINS OVER THE ENTIRE FA WILL
MENTION THAT INTO SUNDAY MORNING TOO. NOT SURE ABOUT DENSE FOG AND
WILL LET LATER SHIFTS MONITOR THAT. THERE IS SOME CLEARING OVER
SOUTHWEST ND WITH WEST/SW WINDS BUT DO NOT EXPECT WINDS TO SWITCH
TO THAT DIRECTION TO HELP SCOUR OUT THE FOG/STRATUS HERE. NOT
SURE IF FOG WILL SCOUR OUT ON SUNDAY EITHER SO BUMPED UP SKY
AMOUNTS THEN TOO.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM CST SAT DEC 20 2014

BY 00Z TUE THE SFC LOW SHOULD MOVE INTO THE ND/SD/MN BORDER REGION
SETTING UP A DECENT SNOW BAND OVER EASTERN ND/EXTREME NW MN...IN
AN INVERTED TROUGH. THIS MAINLY STAYS THE SET UP INTO MON NIGHT OR
EARLY TUE BEFORE SHIFTING OFF TO THE EAST. THIS IS USING THE 12Z
ECMWF/NAM WITH THE OTHER MODELS A LITTLE DIFFERENT. LOOKING AT
RAW SNOWFALL FROM THE ECMWF/NAM WOULD BRING UP TO 6 INCHES OVER
EASTERN ND/FAR NW MN. AT THIS TIME WPC SHOWS ABOUT 4-6 INCHES FROM
EAST CENTRAL ND INTO NW MN. STILL SOME UNCERTAINTY...BUT WILL
ISSUE AN SPS TO HIGHLIGHT THE TRANSITION BACK TO SNOWIER WEATHER.

FOR TUESDAY NIGHT THROUGH FRIDAY...MAIN CHALLENGE IS PCPN AMOUNTS
AND WINDS ON BACK SIDE OF DEPARTING LOW PRESSURE OVER THE GREAT
LAKES ON TUESDAY NIGHT INTO WEDNESDAY. MODELS DIFFERING SOMEWHAT IN
PLACEMENT OF PCPN BAND...BUT FOR THE MOST PART PUTTING IT EAST OF
THE RED RIVER. LOOKING FOR PCPN TO BE IN THE FORM OF SNOW AS MAX
TEMPS ALOFT RANGE FROM -4C TO -7C...AND COLDER AIR WILL CONTINUE TO
WRAP BEHIND THE SYSTEM. WINDS SHOULD BEGIN TO DECREASE AS PRESSURE
GRADIENT WEAKENS...AND SFC HIGH PRESSURE TAKES OVER BY CHRISTMAS DAY
BRINGING DRIER CONDITIONS. OTHERWISE...EXPECT COOLING TEMPERATURES
AND A SLIGHT CHANCE FOR PCPN NEAR THE END OF THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 717 PM CST SAT DEC 20 2014

THE LOW CLOUDS AND IFR CIGS ARE LIKELY HERE TO STAY INTO SUNDAY.
SOUTH WINDS 10 TO 20 MPH. FOG VSBYS ARE THE BIGGEST ISSUES...BUT
THINK MOST TAF SITES TO STAY IN THE 3-5 SM RANGE INTO SUNDAY.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/HOPKINS
AVIATION...RIDDLE






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 914 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 907 PM CST SAT DEC 20 2014

MAIN ISSUE THIS EVENING IS THE FREEZING RAIN AT NORTH CENTRAL. AS
THE PRECIP MOVES EAST INTO COLDER AIR IT IS EXPECTED TO CHANGE
OVER TO SNOW BASED ON MAT TEMP ALOFT FORECAST. WILL RAISE THE
CHANCE TO LIKELY CATEGORY OVER THE NORTH CENTRAL THIS EVENING. SO
FAR WILL HANDLE THIS LIGHT PRECIPITATION WITH SPECIAL WEATHER
STATEMENTS AND SOCIAL MEDIA POSTS.

UPDATE ISSUED AT 644 PM CST SAT DEC 20 2014

SEEING SOME VISIBILITY REDUCTION DUE TO SNOW/MIXED PRECIPITATION AT
TIOGA AND STANLEY WITH A NARROW BAND OF PRECIPITATION. REFINED THIS
AREA IN THE FORECAST ACROSS THE NORTH CENTRAL..AND RAISED POPS T
40 AS IT MOVES TOWARD MINOT. AM CONCERNED ABOUT THE STRATUS ACROSS
THE NORTH CENTRAL AND EAST CENTRAL. HRRR CONTINUES TO SHOW THE
STRATUS FILLING BACK IN ALTHOUGH THE SATELLITE TRENDS SHOW
CONTINUES MOVEMENT EAST OUT OF JAMESTOWN. WILL WATCH FOR THIS
TREND TO CHANGE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)

ISSUED AT 336 PM CST SAT DEC 20 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE LINGERING
PRECIPITATION ASSOCIATED WITH A MID LEVEL WAVE MOVING EAST ACROSS
THE NORTHERN PLAINS TONIGHT...FOG REDEVELOPMENT TONIGHT EASTERN
HALF ALONG TO EAST OF HIGHWAY 83...THEN THE ONSET OF
PRECIPITATION WITH A STRONG STORM SYSTEM ON SUNDAY.

CURRENTLY...MID LEVEL S/WV IMPULSE OVER NORTHWESTERN NORTH DAKOTA
WITH AN ASSOCIATED SFC TROUGH/WARM FRONTAL BOUNDARY DRAPED NORTH
TO SOUTH-SOUTHEAST ACROSS THE CENTRAL DAKOTAS. BAND OF MID LEVEL
CLOUDS AND WEAK RADAR RETURNS ALONG THE BOUNDARY OVER MY EASTERN
COUNTIES AT THE MOMENT...WITH CLEARING SKIES WEST. THE EXCEPTION
IS OVER THE FAR NORTHWEST WHERE WRAP AROUND MOISTURE IS MOVING
INTO...WHERE WE EXPECT INCREASING CLOUDS AND A CHANCE FOR LIGHT
PRECIPITATION EITHER IN THE FORM OF RAIN OR A WINTRY MIX MID TO
LATE AFTERNOON.

WHILE THE BAND OF MID LEVEL CLOUDS IS EATING AWAY AT THE STRATUS
AND FOG CENTRAL INTO EAST...HIGH RES MODELS STRONGLY SUGGEST
REDEVELOPMENT INITIALLY WHERE IT IS AT NOW OVER MY EASTERN
COUNTIES...THEN EXPANDING WEST TO THE HIGHWAY 83 CORRIDOR. WRAP
AROUND PRECIPITATION WILL ALSO WORK ITS WAY EAST TONIGHT ACROSS
THE NORTH BEHIND THE AFOREMENTIONED MID LEVEL WAVE.

NEXT STORM SYSTEM ARRIVES SUNDAY. LEFT EXIT REGION OF A STRONG
UPPER LEVEL JET STREAK WILL PROMOTE LOW PRESSURE DEVELOPMENT OVER
NORTH CENTRAL MONTANA LATE TONIGHT INTO SUNDAY MORNING...WITH
THIS FEATURE THEN MOVING SOUTHEAST INTO EASTERN MONTANA DURING
SUNDAY AFTERNOON. FORCING WILL BE PLENTIFUL WITH INCREASING UPPER
LEVEL DIVERGENCE ON THE NOSE OF THE UPPER JET AND LOW LEVEL
THERMAL UPGLIDE AHEAD OF THE SFC LOW/WARM FRONT. ALREADY PLENTY
OF MOISTURE SO INCREASED POPS TO LIKELY/DEF WEST. THIS EVENT
CONTINUES INTO THE LONG TERM PERIOD SUNDAY NIGHT. SEE BELOW FOR
FURTHER DETAILS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

RAIN...FREEZING RAIN AND SNOW ARE LIKELY ACROSS THE REGION SUNDAY
INTO MONDAY.

FOR THE SUNDAY INTO MONDAY FORECAST WENT WITH A BLEND OF THE 12
UTC ECMWF/GFS/SREF AS THEY HAVE COME INTO BETTER AGREEMENT AND
DEPICT A REASONABLE SCENARIO. THE 12 UTC NAM APPEARED TO BE TOO
SLOW...TOO MOIST AND BROUGHT THE SURFACE LOW FURTHER NORTHEAST THAN THE
REST OF THE GUIDANCE. HOWEVER...IT IS IMPORTANT TO NOTE THAT THE
18 UTC NAM THAT JUST CAME IN HAS COME INTO BETTER AGREEMENT WITH
THE OTHER GUIDANCE AND NOW HAS THE LOW MOVING A BIT QUICKER AND
TRACKING ACROSS SOUTHWEST NORTH DAKOTA.

...THE MAIN FORECAST CHALLENGE AND UNCERTAINTIES WITH THIS SYSTEM ARE
PRECIP TRANSITION TIMES AND AMOUNTS...

RECENT MODEL TRENDS INDICATE WARMER AIR ALOFT WILL NOT BE AS
PRONOUNCED AND THEREFORE PRECIP TYPES SHOULD BE DETERMINED BY
SURFACE TEMPERATURE ALONE AND LIMITED TO RAIN/FREEZING RAIN/SNOW.
INITIALLY DRY AIR IS EXPECTED TO OCCUPY THE 850-700 MB LAYER. THIS
SHOULD LIMIT INITIAL PRECIP TO A LIGHT DRIZZLE...REGARDLESS OF SURFACE
TEMPERATURES...DUE TO LACK OF ICE (NO SNOW ALOFT). AS MOISTURE
FROM THE WEST MOVES IN AND COLD AIR ADVECTION ALOFT TAKES
HOLD...THE COLUMN SHOULD EVENTUALLY SATURATE AND SNOW WOULD LIKELY
FOLLOW. TEMPERATURES SUNDAY AFTERNOON/EVENING SHOULD BE WARM
ENOUGH ACROSS THE SOUTHWEST TO KEEP ALL PRECIPITATION LIQUID
THROUGH THE EARLY EVENING HOURS. THE INITIAL WAVE OF MOISTURE IS
EXPECTED TO ENTER WESTERN NORTH DAKOTA SHORTLY AFTER SUNSET. COLD
AIR SHOULD TAKE HOLD AFTER MIDNIGHT. IT IS AT THIS TIME WHEN A
TRANSITION TO SNOW IS EXPECTED. LIGHT SNOW IS THEN EXPECTED TO
FALL THROUGH THE DAY MONDAY...EVENTUALLY ACCUMULATING AROUND 3
INCHES ACROSS WESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY.
CENTRAL NORTH DAKOTA MAY EXPERIENCE A LOCAL MINIMUM OF SNOWFALL AS
THE LOW IS PROGGED TO PIVOT ALONG THE RED RIVER (KEEPING MOST OF
THE MOISTURE ALONG AND EAST OF THE JAMES VALLEY THROUGH THE DAY).
IN ADDITION TO SNOW...GUSTY WINDS AROUND 35 MPH MAY CREATE SOME
BLOWING SNOW...REDUCING VISIBILITY. THE STRONGEST WINDS ARE
EXPECTED ACROSS SOUTHWEST AND SOUTH CENTRAL NORTH
DAKOTA...COINCIDENT WITH A 10 MB/6 HOUR PRESSURE RISE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 907 PM CST SAT DEC 20 2014

AT 900 PM CST...A WARM FRONT EXTENDED FROM LOW PRESSURE IN
SASKATCHEWAN SOUTHEAST THROUGH CENTRAL NORTH DAKOTA. THE FRONT
WILL BE THE FOCUS FOR A WINTRY MIX OF FREEZING RAIN AND SNOW
BETWEEN MINOT AND RUGBY THROUGH MIDNIGHT. OTHERWISE AREAS OF FOG
WILL AGAIN PLAGUE THE REGION FROM A MINOT TO BISMARCK LINE. IFR
CONDITIONS EAST OF THIS LINE AND VFR WEST. ANOTHER LOW PRESSURE
SYSTEM WILL APPROACH WESTERN NORTH DAKOTA SUNDAY AFTERNOON. THIS
COULD BRING A THREAT FOR FREEZING RAIN/SLEET/SNOW AT KISN AFTER 2
PM CST. LEFT VCSH FOR NOW DUE TO UNCERTAINTY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...NH
LONG TERM...AJ
AVIATION...WAA






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 656 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 644 PM CST SAT DEC 20 2014

SEEING SOME VISIBILITY REDUCTION DUE TO SNOW/MIXED PRECIPITATION AT
TIOGA AND STANLEY WITH A NARROW BAND OF PRECIPITATION. REFINED THIS
AREA IN THE FORECAST ACROSS THE NORTH CENTRAL..AND RAISED POPS T
40 AS IT MOVES TOWARD MINOT. AM CONCERNED ABOUT THE STRATUS ACROSS
THE NORTH CENTRAL AND EAST CENTRAL. HRRR CONTINUES TO SHOW THE
STRATUS FILLING BACK IN ALTHOUGH THE SATELLITE TRENDS SHOW
CONTINUES MOVEMENT EAST OUT OF JAMESTOWN. WILL WATCH FOR THIS
TREND TO CHANGE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)

ISSUED AT 336 PM CST SAT DEC 20 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE LINGERING
PRECIPITATION ASSOCIATED WITH A MID LEVEL WAVE MOVING EAST ACROSS
THE NORTHERN PLAINS TONIGHT...FOG REDEVELOPMENT TONIGHT EASTERN
HALF ALONG TO EAST OF HIGHWAY 83...THEN THE ONSET OF
PRECIPITATION WITH A STRONG STORM SYSTEM ON SUNDAY.

CURRENTLY...MID LEVEL S/WV IMPULSE OVER NORTHWESTERN NORTH DAKOTA
WITH AN ASSOCIATED SFC TROUGH/WARM FRONTAL BOUNDARY DRAPED NORTH
TO SOUTH-SOUTHEAST ACROSS THE CENTRAL DAKOTAS. BAND OF MID LEVEL
CLOUDS AND WEAK RADAR RETURNS ALONG THE BOUNDARY OVER MY EASTERN
COUNTIES AT THE MOMENT...WITH CLEARING SKIES WEST. THE EXCEPTION
IS OVER THE FAR NORTHWEST WHERE WRAP AROUND MOISTURE IS MOVING
INTO...WHERE WE EXPECT INCREASING CLOUDS AND A CHANCE FOR LIGHT
PRECIPITATION EITHER IN THE FORM OF RAIN OR A WINTRY MIX MID TO
LATE AFTERNOON.

WHILE THE BAND OF MID LEVEL CLOUDS IS EATING AWAY AT THE STRATUS
AND FOG CENTRAL INTO EAST...HIGH RES MODELS STRONGLY SUGGEST
REDEVELOPMENT INITIALLY WHERE IT IS AT NOW OVER MY EASTERN
COUNTIES...THEN EXPANDING WEST TO THE HIGHWAY 83 CORRIDOR. WRAP
AROUND PRECIPITATION WILL ALSO WORK ITS WAY EAST TONIGHT ACROSS
THE NORTH BEHIND THE AFOREMENTIONED MID LEVEL WAVE.

NEXT STORM SYSTEM ARRIVES SUNDAY. LEFT EXIT REGION OF A STRONG
UPPER LEVEL JET STREAK WILL PROMOTE LOW PRESSURE DEVELOPMENT OVER
NORTH CENTRAL MONTANA LATE TONIGHT INTO SUNDAY MORNING...WITH
THIS FEATURE THEN MOVING SOUTHEAST INTO EASTERN MONTANA DURING
SUNDAY AFTERNOON. FORCING WILL BE PLENTIFUL WITH INCREASING UPPER
LEVEL DIVERGENCE ON THE NOSE OF THE UPPER JET AND LOW LEVEL
THERMAL UPGLIDE AHEAD OF THE SFC LOW/WARM FRONT. ALREADY PLENTY
OF MOISTURE SO INCREASED POPS TO LIKELY/DEF WEST. THIS EVENT
CONTINUES INTO THE LONG TERM PERIOD SUNDAY NIGHT. SEE BELOW FOR
FURTHER DETAILS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

RAIN...FREEZING RAIN AND SNOW ARE LIKELY ACROSS THE REGION SUNDAY
INTO MONDAY.

FOR THE SUNDAY INTO MONDAY FORECAST WENT WITH A BLEND OF THE 12
UTC ECMWF/GFS/SREF AS THEY HAVE COME INTO BETTER AGREEMENT AND
DEPICT A REASONABLE SCENARIO. THE 12 UTC NAM APPEARED TO BE TOO
SLOW...TOO MOIST AND BROUGHT THE SURFACE LOW FURTHER NORTHEAST THAN THE
REST OF THE GUIDANCE. HOWEVER...IT IS IMPORTANT TO NOTE THAT THE
18 UTC NAM THAT JUST CAME IN HAS COME INTO BETTER AGREEMENT WITH
THE OTHER GUIDANCE AND NOW HAS THE LOW MOVING A BIT QUICKER AND
TRACKING ACROSS SOUTHWEST NORTH DAKOTA.

...THE MAIN FORECAST CHALLENGE AND UNCERTAINTIES WITH THIS SYSTEM ARE
PRECIP TRANSITION TIMES AND AMOUNTS...

RECENT MODEL TRENDS INDICATE WARMER AIR ALOFT WILL NOT BE AS
PRONOUNCED AND THEREFORE PRECIP TYPES SHOULD BE DETERMINED BY
SURFACE TEMPERATURE ALONE AND LIMITED TO RAIN/FREEZING RAIN/SNOW.
INITIALLY DRY AIR IS EXPECTED TO OCCUPY THE 850-700 MB LAYER. THIS
SHOULD LIMIT INITIAL PRECIP TO A LIGHT DRIZZLE...REGARDLESS OF SURFACE
TEMPERATURES...DUE TO LACK OF ICE (NO SNOW ALOFT). AS MOISTURE
FROM THE WEST MOVES IN AND COLD AIR ADVECTION ALOFT TAKES
HOLD...THE COLUMN SHOULD EVENTUALLY SATURATE AND SNOW WOULD LIKELY
FOLLOW. TEMPERATURES SUNDAY AFTERNOON/EVENING SHOULD BE WARM
ENOUGH ACROSS THE SOUTHWEST TO KEEP ALL PRECIPITATION LIQUID
THROUGH THE EARLY EVENING HOURS. THE INITIAL WAVE OF MOISTURE IS
EXPECTED TO ENTER WESTERN NORTH DAKOTA SHORTLY AFTER SUNSET. COLD
AIR SHOULD TAKE HOLD AFTER MIDNIGHT. IT IS AT THIS TIME WHEN A
TRANSITION TO SNOW IS EXPECTED. LIGHT SNOW IS THEN EXPECTED TO
FALL THROUGH THE DAY MONDAY...EVENTUALLY ACCUMULATING AROUND 3
INCHES ACROSS WESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY.
CENTRAL NORTH DAKOTA MAY EXPERIENCE A LOCAL MINIMUM OF SNOWFALL AS
THE LOW IS PROGGED TO PIVOT ALONG THE RED RIVER (KEEPING MOST OF
THE MOISTURE ALONG AND EAST OF THE JAMES VALLEY THROUGH THE DAY).
IN ADDITION TO SNOW...GUSTY WINDS AROUND 35 MPH MAY CREATE SOME
BLOWING SNOW...REDUCING VISIBILITY. THE STRONGEST WINDS ARE
EXPECTED ACROSS SOUTHWEST AND SOUTH CENTRAL NORTH
DAKOTA...COINCIDENT WITH A 10 MB/6 HOUR PRESSURE RISE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 644 PM CST SAT DEC 20 2014

AT 630 PM CST...A WARM FRONT EXTENDED FROM LOW PRESSURE IN
SASKATCHEWAN SOUTHEAST THROUGH CENTRAL NORTH DAKOTA. THE FRONT IS
FORECAST TO MOVE EAST TONIGHT. IFR CONDITIONS AT KJMS WILL
TEMPORARILY IMPROVE TO VFR BRIEFLY THIS EVENING BEFORE RESUMING IFR
AS THE STRATUS FILLS BACK IN. A BAND OF SNOW/MIXED PRECIPITATION
WILL MOVE THROUGH MINOT BETWEEN 01-03Z...WITH ASSOCIATED MVFR
CONDITIONS. EVENTUALITY KMOT WILL RETURN TO IFR IN FOG AFTER 06Z.
OTHERWISE VFR KISN-KDIK-KBIS. ANOTHER LOW PRESSURE SYSTEM WILL
APPROACH WESTERN NORTH DAKOTA SUNDAY AFTERNOON. THIS COULD BRING A
THREAT FOR FREEZING RAIN/SLEET SNOW AT KISN. AFTER 2 PM CST. LEFT
VCSH FOR NOW DUE TO UNCERTAINTY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...NH
LONG TERM...AJ
AVIATION...WAA







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1158 AM CST FRI DEC 19 2014

.UPDATE...
ISSUED AT 1149 AM CST FRI DEC 19 2014

FOG AND STRATUS CONTINUES ACROSS THE NORTH AND PORTIONS OF THE EAST
CENTRAL TODAY. WITH LITTLE TO MOVE THE STATUS AROUND WILL OPT FOR
PERSISTENCE AND KEEP CLOUDS AND FOG IN THROUGH THE AFTERNOON AND
INTO THE EVENING AS WELL.

UPDATE ISSUED AT 943 AM CST FRI DEC 19 2014

WILL EXTEND AREAS OF FOG FOR A FEW MORE HOURS NORTHWEST. OTHERWISE
AS FOG LIFTS PATCHY FREEZING DRIZZLE HAS DIMINISHED. TEMPERATURES
AND WINDS LOOK OK.

UPDATE ISSUED AT 640 AM CST FRI DEC 19 2014

VISIBILITIES IN FOG NORTH AND EAST CONTINUE TO VARY FROM TIME TO
TIME AND PLACE TO PLACE. THERE WAS GENERAL IMPROVEMENT IN
VISIBILITIES. THE DENSE FOG ADVISORY NORTHWEST WAS ALLOWED TO
EXPIRE. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR FOG...SOME
OF IT LOCALLY DENSE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CST FRI DEC 19 2014

FOG AND LOW CLOUDS ARE THE MAIN CONCERNS IN THE SHORT TERM.

CURRENT SURFACE ANALYSIS  INDICATES LOW PRESSURE IN THE LEE OF THE
ROCKIES WITH A TROUGH EXTENDING FROM NORTHERN ALBERTA TO THE WESTERN
DAKOTAS. AT UPPER LEVELS A BROAD TROUGH EXTENDED OVER THE CANADIAN
AND NORTHERN US PLAINS. A RATHER SHARP WESTERN EDGE TO LOW CLOUDS
EXTENDED FROM NEAR WILLISTON ACROSS LAKE SAKAKAWEA TO EAST OF
BISMARCK. MID LEVEL CLOUDS WERE ALONG AND SOUTH/WEST OF THE MISSOURI
RIVER AT 3 AM CST. EXPECT THE LOW CLOUDS TO CLEAR FROM WEST TO EAST
ACROSS SOUTH CENTRAL NORTH DAKOTA...BUT LATEST HRRR MODEL INDICATES
CLOUDS HANGING IN ACROSS THE NORTH. A SHORTWAVE ALOFT ON THE WESTERN
EDGE OF THE UPPER TROUGH WAS DIGGING SOUTHEAST ACROSS SOUTHWESTERN
NORTH DAKOTA INTO WESTERN SOUTH DAKOTA...AND MAY BE THE DRIVING
FORCE FOR THE MID CLOUDS MOVING IN AND THE LOWER CLOUDS DISSIPATING.

DENSE FOG STILL EVIDENT AT WILLISTON...ALTHOUGH VISIBILITIES HAVE
IMPROVED IN THE LAST HOUR AT OTHER PLACES WITHIN THE DENSE FOG
ADVISORY...SUCH AS TIOGA/STANLEY/CROSBY. BUT MINOT VISIBILITY IS ON
A DOWNWARD TREND. THUS WILL KEEP THE DENSE FOG ADVISORY GOING UNTIL
6 AM AND THEN RE-EVALUATE.

OTHERWISE WARM ADVECTION TODAY SHOULD ALLOW TEMPERATURES TO RISE
INTO THE MID/UPPER 20S NORTH AND EAST OF THE MISSOURI RIVER...AND
WELL INTO THE MID AND UPPER 30S SOUTH AND WEST OF THE RIVER. TONIGHT
A SHORTWAVE RIDGE ALOFT ENTERS WESTERN NORTH DAKOTA AHEAD OF AN
UPPER LEVEL SHORTWAVE MOVING EASTWARD OUT OF THE ROCKIES. LOWS
TONIGHT SHOULD REMAIN ABOVE AVERAGE IN THE TEENS AND LOWER 20S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CST FRI DEC 19 2014

THE SHORT TERM ISSUES...LOW CLOUDS AND LIGHT PRECIPITATION
INCLUDING FREEZING RAIN/FREEZING DRIZZLE AND PATCHY FOG...
CONTINUE INTO THE LONG TERM AS THE FORECAST AREA REMAINS UNDER A
MEAN TROUGH SURFACE AND ALOFT. WAVES COMING THROUGH SATURDAY AND
AGAIN SUNDAY ARE WEAK AND MOISTURE STARVED. HOWEVER...WITH WARMER
AIR ADVECTING IN ALOFT AHEAD OF EACH WAVE THERE IS A RISK OF
FREEZING RAIN SATURDAY MORNING / FREEZING DRIZZLE WITH LOW STRATUS
CLOUDS. WARM ADVECTION CONTINUES CHANGING ANY PRECIPITATION IN THE
SOUTHWEST TO RAIN WITH SURFACE TEMPERATURES INTO THE MID 30S
SATURDAY AFTERNOON. A SIMILAR SCENARIO SETS UP FOR SUNDAY.

THE MID LEVEL LOW...CUTTING OFF OVER WISCONSIN...WILL BLOCK THE
FLOW PATTERN UP ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW COLDER
AIR TO SPILL IN FOR TUESDAY. LOOKING AHEAD TO CHRISTMAS DAY...THE
LOW TO THE EAST...AND HIGH PRESSURE MOVING ACROSS THE NORTHERN
ROCKIES...ALLOW A STEADY FLOW OF COLDER AIR INTO NORTH
DAKOTA...THAT WILL CONTINUE AT LEAST THROUGH THE HOLIDAY WEEKEND.
STILL THOUGH...TEMPERATURES ARE CLOSE TO WHAT IS NORMAL FOR THE
END OF DECEMBER...AROUND 20 DAYTIME AND SINGLE DIGITS ABOVE AND
BELOW AT NIGHT. PERIODS OF FLURRIES...MAYBE A FEW TENTHS INCH OF
SNOW AT MOST EVERY OTHER DAY OR SO...LOOKS TO OCCUR THROUGH THE
CHRISTMAS HOLIDAY WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1149 AM CST FRI DEC 19 2014

WILL LET PERSISTENCE DICTATE THE FORECAST WHERE LOW CLOUDS AND
AREAS OF FOG REMAIN AT NOON TODAY. KEPT LOW IFR FROM KMOT-KJMS
WHERE SHALLOW COOL AIR WILL REMAIN. KISN-KBIS WILL REMAIN ON THE
EDGE WITH SOME UNCERTAINTY AS TO THE EXTENT OF CLOUDS AND FOG
THAT RETURN AFTER DARK. WITH LITTLE IN THE WAY OF BROAD SCALE
WINDS SEE SHALLOW COOL BOUNDARY LAYER CONTRIBUTING TO STRATUS AND
FOG. KDIK PROBABLY THE ONLY ONE IN THE CLEAR WITH VFR EXPECTED.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...WAA






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 944 AM CST FRI DEC 19 2014

.UPDATE...
ISSUED AT 943 AM CST FRI DEC 19 2014

WILL EXTEND AREAS OF FOG FOR A FEW MORE HOURS NORTHWEST. OTHERWISE
AS FOG LIFTS PATCHY FREEZING DRIZZLE HAS DIMINISHED. TEMPERATURES
AND WINDS LOOK OK.

UPDATE ISSUED AT 640 AM CST FRI DEC 19 2014

VISIBILITIES IN FOG NORTH AND EAST CONTINUE TO VARY FROM TIME TO
TIME AND PLACE TO PLACE. THERE WAS GENERAL IMPROVEMENT IN
VISIBILITIES. THE DENSE FOG ADVISORY NORTHWEST WAS ALLOWED TO
EXPIRE. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR FOG...SOME
OF IT LOCALLY DENSE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CST FRI DEC 19 2014

FOG AND LOW CLOUDS ARE THE MAIN CONCERNS IN THE SHORT TERM.

CURRENT SURFACE ANALYSIS  INDICATES LOW PRESSURE IN THE LEE OF THE
ROCKIES WITH A TROUGH EXTENDING FROM NORTHERN ALBERTA TO THE WESTERN
DAKOTAS. AT UPPER LEVELS A BROAD TROUGH EXTENDED OVER THE CANADIAN
AND NORTHERN US PLAINS. A RATHER SHARP WESTERN EDGE TO LOW CLOUDS
EXTENDED FROM NEAR WILLISTON ACROSS LAKE SAKAKAWEA TO EAST OF
BISMARCK. MID LEVEL CLOUDS WERE ALONG AND SOUTH/WEST OF THE MISSOURI
RIVER AT 3 AM CST. EXPECT THE LOW CLOUDS TO CLEAR FROM WEST TO EAST
ACROSS SOUTH CENTRAL NORTH DAKOTA...BUT LATEST HRRR MODEL INDICATES
CLOUDS HANGING IN ACROSS THE NORTH. A SHORTWAVE ALOFT ON THE WESTERN
EDGE OF THE UPPER TROUGH WAS DIGGING SOUTHEAST ACROSS SOUTHWESTERN
NORTH DAKOTA INTO WESTERN SOUTH DAKOTA...AND MAY BE THE DRIVING
FORCE FOR THE MID CLOUDS MOVING IN AND THE LOWER CLOUDS DISSIPATING.

DENSE FOG STILL EVIDENT AT WILLISTON...ALTHOUGH VISIBILITIES HAVE
IMPROVED IN THE LAST HOUR AT OTHER PLACES WITHIN THE DENSE FOG
ADVISORY...SUCH AS TIOGA/STANLEY/CROSBY. BUT MINOT VISIBILITY IS ON
A DOWNWARD TREND. THUS WILL KEEP THE DENSE FOG ADVISORY GOING UNTIL
6 AM AND THEN RE-EVALUATE.

OTHERWISE WARM ADVECTION TODAY SHOULD ALLOW TEMPERATURES TO RISE
INTO THE MID/UPPER 20S NORTH AND EAST OF THE MISSOURI RIVER...AND
WELL INTO THE MID AND UPPER 30S SOUTH AND WEST OF THE RIVER. TONIGHT
A SHORTWAVE RIDGE ALOFT ENTERS WESTERN NORTH DAKOTA AHEAD OF AN
UPPER LEVEL SHORTWAVE MOVING EASTWARD OUT OF THE ROCKIES. LOWS
TONIGHT SHOULD REMAIN ABOVE AVERAGE IN THE TEENS AND LOWER 20S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CST FRI DEC 19 2014

THE SHORT TERM ISSUES...LOW CLOUDS AND LIGHT PRECIPITATION
INCLUDING FREEZING RAIN/FREEZING DRIZZLE AND PATCHY FOG...
CONTINUE INTO THE LONG TERM AS THE FORECAST AREA REMAINS UNDER A
MEAN TROUGH SURFACE AND ALOFT. WAVES COMING THROUGH SATURDAY AND
AGAIN SUNDAY ARE WEAK AND MOISTURE STARVED. HOWEVER...WITH WARMER
AIR ADVECTING IN ALOFT AHEAD OF EACH WAVE THERE IS A RISK OF
FREEZING RAIN SATURDAY MORNING / FREEZING DRIZZLE WITH LOW STRATUS
CLOUDS. WARM ADVECTION CONTINUES CHANGING ANY PRECIPITATION IN THE
SOUTHWEST TO RAIN WITH SURFACE TEMPERATURES INTO THE MID 30S
SATURDAY AFTERNOON. A SIMILAR SCENARIO SETS UP FOR SUNDAY.

THE MID LEVEL LOW...CUTTING OFF OVER WISCONSIN...WILL BLOCK THE
FLOW PATTERN UP ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW COLDER
AIR TO SPILL IN FOR TUESDAY. LOOKING AHEAD TO CHRISTMAS DAY...THE
LOW TO THE EAST...AND HIGH PRESSURE MOVING ACROSS THE NORTHERN
ROCKIES...ALLOW A STEADY FLOW OF COLDER AIR INTO NORTH
DAKOTA...THAT WILL CONTINUE AT LEAST THROUGH THE HOLIDAY WEEKEND.
STILL THOUGH...TEMPERATURES ARE CLOSE TO WHAT IS NORMAL FOR THE
END OF DECEMBER...AROUND 20 DAYTIME AND SINGLE DIGITS ABOVE AND
BELOW AT NIGHT. PERIODS OF FLURRIES...MAYBE A FEW TENTHS INCH OF
SNOW AT MOST EVERY OTHER DAY OR SO...LOOKS TO OCCUR THROUGH THE
CHRISTMAS HOLIDAY WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI DEC 19 2014

A MOIST SOUTHERLY FLOW CONTINUES TO PRODUCE WIDESPREAD MVFR-IFR
STRATUS ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA. A WEAK TROUGH OF
LOW PRESSURE WAS PROVIDING MID CLOUDS ACROSS SOUTHWEST NORTH
DAKOTA. THIS TROUGH WILL CLEAR THE STRATUS AT KISN AROUND 15 UTC.
KMOT AND KJMS WILL REMAIN IN MVFR-IFR STRATUS INTO THIS
AFTERNOON. THE MOISTURE REMAINS TRAPPED ALONG THE CANADIAN BORDER
WHICH COULD KEEP KMOT IN THE MVFR-IFR STRATUS AT LEAST THROUGH MID
AFTERNOON. ONCE THE STRATUS CLEARS THE TAF SITES VFR CONDITIONS
ARE THEN EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 641 AM CST FRI DEC 19 2014

.UPDATE...
ISSUED AT 640 AM CST FRI DEC 19 2014

VISIBILITIES IN FOG NORTH AND EAST CONTINUE TO VARY FROM TIME TO
TIME AND PLACE TO PLACE. THERE WAS GENERAL IMPROVEMENT IN
VISIBILITIES. THE DENSE FOG ADVISORY NORTHWEST WAS ALLOWED TO
EXPIRE. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR FOG...SOME
OF IT LOCALLY DENSE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CST FRI DEC 19 2014

FOG AND LOW CLOUDS ARE THE MAIN CONCERNS IN THE SHORT TERM.

CURRENT SURFACE ANALYSIS  INDICATES LOW PRESSURE IN THE LEE OF THE
ROCKIES WITH A TROUGH EXTENDING FROM NORTHERN ALBERTA TO THE WESTERN
DAKOTAS. AT UPPER LEVELS A BROAD TROUGH EXTENDED OVER THE CANADIAN
AND NORTHERN US PLAINS. A RATHER SHARP WESTERN EDGE TO LOW CLOUDS
EXTENDED FROM NEAR WILLISTON ACROSS LAKE SAKAKAWEA TO EAST OF
BISMARCK. MID LEVEL CLOUDS WERE ALONG AND SOUTH/WEST OF THE MISSOURI
RIVER AT 3 AM CST. EXPECT THE LOW CLOUDS TO CLEAR FROM WEST TO EAST
ACROSS SOUTH CENTRAL NORTH DAKOTA...BUT LATEST HRRR MODEL INDICATES
CLOUDS HANGING IN ACROSS THE NORTH. A SHORTWAVE ALOFT ON THE WESTERN
EDGE OF THE UPPER TROUGH WAS DIGGING SOUTHEAST ACROSS SOUTHWESTERN
NORTH DAKOTA INTO WESTERN SOUTH DAKOTA...AND MAY BE THE DRIVING
FORCE FOR THE MID CLOUDS MOVING IN AND THE LOWER CLOUDS DISSIPATING.

DENSE FOG STILL EVIDENT AT WILLISTON...ALTHOUGH VISIBILITIES HAVE
IMPROVED IN THE LAST HOUR AT OTHER PLACES WITHIN THE DENSE FOG
ADVISORY...SUCH AS TIOGA/STANLEY/CROSBY. BUT MINOT VISIBILITY IS ON
A DOWNWARD TREND. THUS WILL KEEP THE DENSE FOG ADVISORY GOING UNTIL
6 AM AND THEN RE-EVALUATE.

OTHERWISE WARM ADVECTION TODAY SHOULD ALLOW TEMPERATURES TO RISE
INTO THE MID/UPPER 20S NORTH AND EAST OF THE MISSOURI RIVER...AND
WELL INTO THE MID AND UPPER 30S SOUTH AND WEST OF THE RIVER. TONIGHT
A SHORTWAVE RIDGE ALOFT ENTERS WESTERN NORTH DAKOTA AHEAD OF AN
UPPER LEVEL SHORTWAVE MOVING EASTWARD OUT OF THE ROCKIES. LOWS
TONIGHT SHOULD REMAIN ABOVE AVERAGE IN THE TEENS AND LOWER 20S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CST FRI DEC 19 2014

THE SHORT TERM ISSUES...LOW CLOUDS AND LIGHT PRECIPITATION
INCLUDING FREEZING RAIN/FREEZING DRIZZLE AND PATCHY FOG...
CONTINUE INTO THE LONG TERM AS THE FORECAST AREA REMAINS UNDER A
MEAN TROUGH SURFACE AND ALOFT. WAVES COMING THROUGH SATURDAY AND
AGAIN SUNDAY ARE WEAK AND MOISTURE STARVED. HOWEVER...WITH WARMER
AIR ADVECTING IN ALOFT AHEAD OF EACH WAVE THERE IS A RISK OF
FREEZING RAIN SATURDAY MORNING / FREEZING DRIZZLE WITH LOW STRATUS
CLOUDS. WARM ADVECTION CONTINUES CHANGING ANY PRECIPITATION IN THE
SOUTHWEST TO RAIN WITH SURFACE TEMPERATURES INTO THE MID 30S
SATURDAY AFTERNOON. A SIMILAR SCENARIO SETS UP FOR SUNDAY.

THE MID LEVEL LOW...CUTTING OFF OVER WISCONSIN...WILL BLOCK THE
FLOW PATTERN UP ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW COLDER
AIR TO SPILL IN FOR TUESDAY. LOOKING AHEAD TO CHRISTMAS DAY...THE
LOW TO THE EAST...AND HIGH PRESSURE MOVING ACROSS THE NORTHERN
ROCKIES...ALLOW A STEADY FLOW OF COLDER AIR INTO NORTH
DAKOTA...THAT WILL CONTINUE AT LEAST THROUGH THE HOLIDAY WEEKEND.
STILL THOUGH...TEMPERATURES ARE CLOSE TO WHAT IS NORMAL FOR THE
END OF DECEMBER...AROUND 20 DAYTIME AND SINGLE DIGITS ABOVE AND
BELOW AT NIGHT. PERIODS OF FLURRIES...MAYBE A FEW TENTHS INCH OF
SNOW AT MOST EVERY OTHER DAY OR SO...LOOKS TO OCCUR THROUGH THE
CHRISTMAS HOLIDAY WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI DEC 19 2014

A MOIST SOUTHERLY FLOW CONTINUES TO PRODUCE WIDESPREAD MVFR-IFR
STRATUS ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA. A WEAK TROUGH OF
LOW PRESSURE WAS PROVIDING MID CLOUDS ACROSS SOUTHWEST NORTH
DAKOTA. THIS TROUGH WILL CLEAR THE STRATUS AT KISN AROUND 15 UTC.
KMOT AND KJMS WILL REMAIN IN MVFR-IFR STRATUS INTO THIS
AFTERNOON. THE MOISTURE REMAINS TRAPPED ALONG THE CANADIAN BORDER
WHICH COULD KEEP KMOT IN THE MVFR-IFR STRATUS AT LEAST THROUGH MID
AFTERNOON. ONCE THE STRATUS CLEARS THE TAF SITES VFR CONDITIONS
ARE THEN EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JPM
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV





AREA FORECAST DISCUSSION

NWS BISMARCK ND

 405 AM CST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CST FRI DEC 19 2014

FOG AND LOW CLOUDS ARE THE MAIN CONCERNS IN THE SHORT TERM.

CURRENT SURFACE ANALYSIS  INDICATES LOW PRESSURE IN THE LEE OF THE
ROCKIES WITH A TROUGH EXTENDING FROM NORTHERN ALBERTA TO THE WESTERN
DAKOTAS. AT UPPER LEVELS A BROAD TROUGH EXTENDED OVER THE CANADIAN
AND NORTHERN US PLAINS. A RATHER SHARP WESTERN EDGE TO LOW CLOUDS
EXTENDED FROM NEAR WILLISTON ACROSS LAKE SAKAKAWEA TO EAST OF
BISMARCK. MID LEVEL CLOUDS WERE ALONG AND SOUTH/WEST OF THE MISSOURI
RIVER AT 3 AM CST. EXPECT THE LOW CLOUDS TO CLEAR FROM WEST TO EAST
ACROSS SOUTH CENTRAL NORTH DAKOTA...BUT LATEST HRRR MODEL INDICATES
CLOUDS HANGING IN ACROSS THE NORTH. A SHORTWAVE ALOFT ON THE WESTERN
EDGE OF THE UPPER TROUGH WAS DIGGING SOUTHEAST ACROSS SOUTHWESTERN
NORTH DAKOTA INTO WESTERN SOUTH DAKOTA...AND MAY BE THE DRIVING
FORCE FOR THE MID CLOUDS MOVING IN AND THE LOWER CLOUDS DISSIPATING.

DENSE FOG STILL EVIDENT AT WILLISTON...ALTHOUGH VISIBILITIES HAVE
IMPROVED IN THE LAST HOUR AT OTHER PLACES WITHIN THE DENSE FOG
ADVISORY...SUCH AS TIOGA/STANLEY/CROSBY. BUT MINOT VISIBILITY IS ON
A DOWNWARD TREND. THUS WILL KEEP THE DENSE FOG ADVISORY GOING UNTIL
6 AM AND THEN RE-EVALUATE.

OTHERWISE WARM ADVECTION TODAY SHOULD ALLOW TEMPERATURES TO RISE
INTO THE MID/UPPER 20S NORTH AND EAST OF THE MISSOURI RIVER...AND
WELL INTO THE MID AND UPPER 30S SOUTH AND WEST OF THE RIVER. TONIGHT
A SHORTWAVE RIDGE ALOFT ENTERS WESTERN NORTH DAKOTA AHEAD OF AN
UPPER LEVEL SHORTWAVE MOVING EASTWARD OUT OF THE ROCKIES. LOWS
TONIGHT SHOULD REMAIN ABOVE AVERAGE IN THE TEENS AND LOWER 20S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CST FRI DEC 19 2014

THE SHORT TERM ISSUES...LOW CLOUDS AND LIGHT PRECIPITATION
INCLUDING FREEZING RAIN/FREEZING DRIZZLE AND PATCHY FOG...
CONTINUE INTO THE LONG TERM AS THE FORECAST AREA REMAINS UNDER A
MEAN TROUGH SURFACE AND ALOFT. WAVES COMING THROUGH SATURDAY AND
AGAIN SUNDAY ARE WEAK AND MOISTURE STARVED. HOWEVER...WITH WARMER
AIR ADVECTING IN ALOFT AHEAD OF EACH WAVE THERE IS A RISK OF
FREEZING RAIN SATURDAY MORNING / FREEZING DRIZZLE WITH LOW STRATUS
CLOUDS. WARM ADVECTION CONTINUES CHANGING ANY PRECIPITATION IN THE
SOUTHWEST TO RAIN WITH SURFACE TEMPERATURES INTO THE MID 30S
SATURDAY AFTERNOON. A SIMILAR SCENARIO SETS UP FOR SUNDAY.

THE MID LEVEL LOW...CUTTING OFF OVER WISCONSIN...WILL BLOCK THE
FLOW PATTERN UP ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW COLDER
AIR TO SPILL IN FOR TUESDAY. LOOKING AHEAD TO CHRISTMAS DAY...THE
LOW TO THE EAST...AND HIGH PRESSURE MOVING ACROSS THE NORTHERN
ROCKIES...ALLOW A STEADY FLOW OF COLDER AIR INTO NORTH
DAKOTA...THAT WILL CONTINUE AT LEAST THROUGH THE HOLIDAY WEEKEND.
STILL THOUGH...TEMPERATURES ARE CLOSE TO WHAT IS NORMAL FOR THE
END OF DECEMBER...AROUND 20 DAYTIME AND SINGLE DIGITS ABOVE AND
BELOW AT NIGHT. PERIODS OF FLURRIES...MAYBE A FEW TENTHS INCH OF
SNOW AT MOST EVERY OTHER DAY OR SO...LOOKS TO OCCUR THROUGH THE
CHRISTMAS HOLIDAY WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI DEC 19 2014

A MOIST SOUTHERLY FLOW CONTINUES TO PRODUCE WIDESPREAD MVFR-IFR
STRATUS ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA. A WEAK TROUGH OF
LOW PRESSURE...WITH A SOUTHWEST FLOW BEHIND IT...IS IS PROVIDING
CLEARING SKIES ACROSS SOUTHWEST NORTH DAKOTA. THIS TROUGH WILL CLEAR
THE STRATUS AT KBIS AND POSSIBLY KISN AROUND 06 UTC. HOWEVER...WITH
THE CLEAR SKIES AREAS OF FOG WITH IFR CIGS/VSBYS WILL BE POSSIBLE AT
THESE SITES THROUGH EARLY MORNING FRIDAY. KMOT AND KJMS WILL REMAIN
IN MVFR-IFR STRATUS INTO FRIDAY MORNING. KJMS SHOULD CLEAR DURING
THE MORNING BUT THE MOISTURE REMAINS TRAPPED ALONG THE CANADIAN
BORDER WHICH COULD KEEP KMOT IN THE MVFR-IFR STRATUS AT LEAST
THROUGH MIDDAY FRIDAY. ONCE THE STRATUS CLEARS THE TAF SITES...AND
THE THREAT OF PATCHY MORNING FOG HAS ENDED...VFR CONDITIONS ARE THEN
EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD. WINDS WILL
REMAIN LIGHT FROM THE SOUTH TO SOUTHWEST.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
NDZ001>003-009>011.

&&

$$

SHORT TERM...JV
LONG TERM...JPM
AVIATION...TWH






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1245 AM CST FRI DEC 19 2014

.UPDATE...
ISSUED AT 1245 AM CST FRI DEC 19 2014

DENSE FOG HAD DEVELOPED OVER NORTHEASTERN MONTANA AND HAD SPREAD
INTO NORTHWESTERN NORTH DAKOTA. HRRR SHORT TERM MODEL SUGGESTS LOW
VISIBILITIES ALSO FARTHER EAST TOWARDS THE MINOT AREA. THEREFORE
HAVE ISSUED A DENSE FOG ADVISORY FOR DIVIDE AND WILLIAMS
COUNTIES...BURKE AND MOUNTRAIL COUNTIES...AND RENVILLE AND WARD
COUNTIES UNTIL 6 AM CST. WATFORD CITY HAD REPORTED 1/4 MILE
VISIBILITY...BUT LATEST SATELLITE PICS SHOWED A TREND OF MID
CLOUDS MOVING EASTWARD OUT OF MONTANA - WHICH WOULD HELP BREAK UP
FOG SOUTH OF THE MISSOURI RIVER. THUS KEPT THOSE COUNTIES SOUTH OF
THE MISSOURI OUT OF THE DENSE FOG ADVISORY. OTHERWISE CURRENT
FORECAST ON TRACK.

UPDATE ISSUED AT 957 PM CST THU DEC 18 2014

ONLY SOME MINOR UPDATES LATE THIS EVENING. ADDED A MENTION OF FOG
MOST EVERYWHERE EXCEPT THE FAR SOUTHWEST. FOG IS BECOMING MORE
PREVALENT OVER THE NORTHEAST CWA. STILL THINK AREAS JUST WEST OF
THE CLEARING WILL FOG IN A LITTLE ALSO. UPDATED TEMPERATURES BASED
ON LATEST OBSERVATIONS.

UPDATE ISSUED AT 810 PM CST THU DEC 18 2014

AREA OF SNOW SHOWERS WILL MOVE OUT OF EASTERN DICKEY/LAMOURE
COUNTIES DIRECTLY. OTHERWISE STRATUS REMAINS ACROSS MUCH OF
WESTERN AND CENTRAL NORTH DAKOTA. A FEW REPORTS OF VERY LIGHT
FREEZING DRIZZLE THIS EVENING...AND DONT THINK FZDZ CAN BE RULED
OUT ANYWHERE WE HAVE THE STRATUS. THUS HAVE ADDED A MENTION OF
PATCHY FREEZING DRIZZLE...ALONG WITH SCATTERED FLURRIES WHEREVER
WE HAVE THE LOW STRATUS. THIS IS MAINLY ALONG AND TO THE NORTH AND
EAST OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. SKIES HAVE CLEARED
OVER MOST OF SOUTHWEST NORTH DAKOTA. HOWEVER WITH ABUNDANT LOW
LEVEL MOISTURE REMAINING...WILL MENTION PATCHY FOG OVER A GOOD
PORTION OF THE SOUTHWEST. DICKINSON CLEARED OUT AND DROPPED DOWN
TO A QUARTER MILE BRIEFLY...BEFORE SETTLING AROUND 3SM. ALSO
ADJUSTED TEMPERATURES UP ACROSS THE NORTH CENTRAL THROUGH THE
JAMES RIVER VALLEY. STRATUS IS EXPECTED TO REMAIN HERE THROUGH THE
NIGHT...WHICH SHOULD HOLD TEMPERATURES FAIRLY STEADY. TEMPERATURES
WERE LOWERED OVER PORTIONS OF THE SOUTHWEST WHERE SKIES HAVE
CLEARED.

UPDATE ISSUED AT 602 PM CST THU DEC 18 2014

ONLY A COUPLE MINOR CHANGES TO THE EARLY EVENING UPDATE. LOWERED
CLOUD COVER OVER THE SOUTHWEST WHERE LOW STRATUS HAS CLEARED. ALSO
REMOVED MENTION OF FLURRIES FOR THIS AREA. ADJUSTED MENTION OF
FREEZING DRIZZLE A LITTLE NORTH INTO STUTSMAN COUNTY OVER THE
SOUTHEAST CWA THROUGH 9 PM CENTRAL BASED ON CURRENT RADAR RETURNS.
OTHERWISE NO SIGNIFICANT CHANGES.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 332 PM CST THU DEC 18 2014

CURRENT SURFACE ANALYSIS PLACES TROUGH DROPPING DOWN FROM NEAR THE
ALBERTA/SASKATCHEWAN LINE TOWARDS THE WESTERN DAKOTAS. UPPER LEVEL
ANALYSIS PLACES UPPER LOW PUSHING THROUGH EASTERN NORTH DAKOTA.
SOME LIGHT SNOW WITH THIS SYSTEM CONTINUES OVER PORTIONS OF SOUTH
CENTRAL NORTH DAKOTA SLIDING INTO THE JAMES RIVER VALLEY.

FOR TONIGHT...BROAD LAYER OF LOW CLOUD COVER WILL SLOWLY ERODE
OVER THE SOUTHWEST...THOUGH WILL REMAIN IN PLACE OVER REMAINING
AREAS. SOME FLURRIES WILL BE POSSIBLE...WHILE OVER THE FAR
SOUTHERN JAMES RIVER VALLEY FORECAST SOUNDINGS SUGGEST THERE MAY
BE A BRIEF PERIOD OF VERY LIGHT FREEZING DRIZZLE EARLY THIS EVENING.

ON FRIDAY...QUIET WEATHER IS EXPECTED WITH CLOUDS SLOWLY ERODING
AS WEAK RIDGE MAKES ITS APPROACH. WARMER AIR WILL CONTINUE TO
PUSH INTO THE AREA BRINGING TEMPERATURES NEAR TO SLIGHTLY ABOVE
AVERAGE.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED A 332 PM CST THU DEC 18 2014

FOCUS IN THE LONG TERM IS ON THE WEAK SHORTWAVE ON SATURDAY AND THEN
THE LARGE TROUGH SETTING UP OVER THE CENTRAL CONUS SUNDAY INTO NEXT
WEEK.

A WEAK SHORTWAVE IS FORECAST TO MOVE EASTWARD ACROSS THE STATE
SATURDAY. THE 12 UTC MODEL GUIDANCE SHOWS VERY SCATTERED
PRECIPITATION ACROSS THE STATE...HOWEVER PAST MODEL RUNS AND CURRENT
GUIDANCE SHOWS THE BEST CHANCE...ONLY SLIGHT...OVER NORTHWEST NORTH
DAKOTA INTO EASTERN MONTANA. A WEAK SURFACE WARM FRONT WILL
ACCOMPANY THE SHORTWAVE...FOLLOWED QUICKLY BY A WEAK COLD FRONT.
EARLY IN THE DAY SATURDAY THE WARM LAYER ALOFT MAY MELT THE
SNOW...HOWEVER BELOW FREEZING TEMPERATURES AT THE SURFACE WILL MOST
LIKELY REFREEZE THE PRECIPITATION INTO SLEET. AS THE DAY PROGRESSES
THE WARM LAYER ALOFT WILL COOL TO BELOW FREEZING AND SURFACE
TEMPERATURES WILL ACTUALLY WARM TO ABOVE FREEZING...CAUSING ANY
FALLING PRECIPITATION TO TRANSITION TO A MIXTURE OF FREEZING
RAIN...SNOW...AND RAIN. WITH ALL THAT SAID ACCUMULATIONS OF ANY KIND
ARE EXPECTED TO BE VERY LIGHT...WITH MINIMAL IMPACTS.

A MORE SIGNIFICANT TROUGH DEVELOPS OVER THE DAKOTAS SUNDAY...DEEPENS
AND PROPAGATES EAST INTO MINNESOTA AND THE GREAT LAKES REGION MONDAY
INTO NEXT WEEK. WARM ADVECTION AHEAD OF THE SYSTEM AND COLD
ADVECTION BEHIND IT WILL BRING MORE CHANCES OF A WINTRY MIX OF
SLEET...FREEZING RAIN OR DRIZZLE...RAIN...AND SNOW TO NORTH DAKOTA
ON SUNDAY AND MONDAY. ALTHOUGH TEMPERATURES FOR MOST OF NORTH DAKOTA
WILL BE BELOW FREEZING...THE LACK OF ICE CRYSTALS IN CLOUDS MAY
CAUSE PRECIPITATION TO FALL AS FREEZING RAIN OR DRIZZLE. ONCE AGAIN
ANY ACCUMULATIONS ARE EXPECTED TO BE LIGHT OVER WESTERN AND CENTRAL
NORTH DAKOTA...HOWEVER MODELS HAVE CONTINUED TO STRENGTHEN THIS
SYSTEM OVER THE PAST FEW DAYS AND IT WILL HAVE TO BE WATCHED CLOSELY
TO SEE IF ANY MORE PRECIPITATION IS PUSHED INTO NORTH DAKOTA.

AS THE TROUGH PROPAGATES TOWARD THE EAST COAST NORTHWEST FLOW WILL
SET UP OVER NORTH DAKOTA. TEMPERATURES WILL PROGRESSIVELY GET COLDER
WITH A MORE ACTIVE WEATHER PATTERN IN STORE FOR THE NORTHERN PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI DEC 19 2014

A MOIST SOUTHERLY FLOW CONTINUES TO PRODUCE WIDESPREAD MVFR-IFR
STRATUS ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA. A WEAK TROUGH OF
LOW PRESSURE...WITH A SOUTHWEST FLOW BEHIND IT...IS IS PROVIDING
CLEARING SKIES ACROSS SOUTHWEST NORTH DAKOTA. THIS TROUGH WILL CLEAR
THE STRATUS AT KBIS AND POSSIBLY KISN AROUND 06 UTC. HOWEVER...WITH
THE CLEAR SKIES AREAS OF FOG WITH IFR CIGS/VSBYS WILL BE POSSIBLE AT
THESE SITES THROUGH EARLY MORNING FRIDAY. KMOT AND KJMS WILL REMAIN
IN MVFR-IFR STRATUS INTO FRIDAY MORNING. KJMS SHOULD CLEAR DURING
THE MORNING BUT THE MOISTURE REMAINS TRAPPED ALONG THE CANADIAN
BORDER WHICH COULD KEEP KMOT IN THE MVFR-IFR STRATUS AT LEAST
THROUGH MIDDAY FRIDAY. ONCE THE STRATUS CLEARS THE TAF SITES...AND
THE THREAT OF PATCHY MORNING FOG HAS ENDED...VFR CONDITIONS ARE THEN
EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD. WINDS WILL
REMAIN LIGHT FROM THE SOUTH TO SOUTHWEST.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
NDZ001>003-009>011.

&&

$$

UPDATE...JV
SHORT TERM...JJS
LONG TERM...MM
AVIATION...TWH






AREA FORECAST DISCUSSION

NWS WILMINGTON OH

 109 AM EST FRI DEC 19 2014

.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL PUSH SLOWLY EAST ACROSS THE
REGION THROUGH THE WEEKEND...LEADING TO PRIMARILY DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS THE SURFACE PRESSURE GRADIENT CONTINUES TO RELAX ACROSS THE
OHIO VALLEY...ASCENT FROM A WEAKENING MID-LEVEL WAVE IS ALSO
MOVING OFF TO THE EAST. THIS IS LEADING TO A DIMINISHING TREND IN
RADAR ECHOES...AND FLURRIES OVER THE ILN FORECAST AREA HAVE JUST
ABOUT ENDED.

FORECAST TRENDS ARE RIGHT ON TRACK...AND MIN TEMPS WERE NOT
ADJUSTED AT ALL. THE CLOUD FORECAST IS SIMILAR TO YESTERDAY...BUT
THERE HAS BEEN SOME EROSION IN THE LOWEST LAYER OF CLOUDS
(1500-2500 FEET) IN THE SOUTHERN HALF OF THE FORECAST AREA. THE
00Z KILN SOUNDING DOES NOT SHOW A WELL-DEFINED LAYER OF SATURATION
BELOW 800MB AS HAS BEEN THE CASE FOR THE PAST SEVERAL SOUNDINGS.
REGARDLESS...MID-LEVEL CLOUDS (6000-1000 FEET) ARE FAIRLY
THICK...AND SKY GRIDS REMAIN AT 90-100 PERCENT THROUGH THE
OVERNIGHT.

PREVIOUS DISCUSSION >
UPR LVL S/WV WILL PASS EAST ACRS OUR REGION THROUGH THIS EVENING.
FORCING IS WEAK WITH MOST AREAS JUST SEEING A FEW FLURRIES. THERE
COULD BE A FEW SNOW SHOWERS WITH JUST A LIGHT DUSTING ALONG THE
I-70 CORRIDOR WHERE DEEPEST MOISTURE WILL INTERSECT WEAK FORCING.
LOW LEVEL CLOUDS WILL CONTINUE TO BE AN ISSUE AS THE RAP MODEL
SHOWS REGION STAYING PRETTY MUCH OVERCAST OVERNIGHT. LOWS WILL
DROP INTO THE LOWER AND MID 20S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
WEAK SFC HIGH PRESSURE WILL SLOWLY BUILD INTO THE AREA ON FRIDAY.
DESPITE THIS FEATURE...IT LOOKS LIKE LOW LEVEL MOISTURE WILL HANG
AROUND AS IT BECOMES TRAPPED UNDERNEATH THE HIGH. WILL CONTINUE
WITH MAINLY CLOUDY SKIES. HIGHS WILL RANGE FROM THE LOWER TO MID
30S.

FOR FRIDAY NIGHT INTO SATURDAY...LATEST MODEL FORECASTS KEEP THE
AFFECTS OF AN UPR LVL S/WV TO OUR SOUTH WHILE SFC RIDGING REMAINS
IN PLACE. IT IS DIFFICULT TO KNOW IF THE LOW LEVEL CLOUDS WILL
ERODE DURING THIS TIME FRAME. HOWEVER...WITH AN INCREASE IN MID
AND HIGH LEVEL MOISTURE...IT WILL LIKELY REMAIN MOSTLY CLOUDY. IT
WILL BE A LITTLE WARMER ON SATURDAY WITH HIGHS IN THE MID AND
UPPER 30S.

BY SATURDAY NIGHT...HIGH PRESSURE WILL CONTINUE TO EXTEND ACROSS
THE GREAT LAKES AND OHIO VALLEY WHILE A WEAK UPR LVL S/WV PASSES
ACRS THE SOUTHERN GREAT LAKES. PARTLY CLOUDY SKIES ARE EXPECTED.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE CENTERED TO THE NORTHEAST WILL BRING DRY WEATHER ON
SUNDAY. INCREASING MOISTURE AND LIFT WELL AHEAD OF DEVELOPING LOW
PRESSURE MAY PRODUCE LIGHT RAIN AND SNOW ON MONDAY. AS THE LOW MOVES
TO LAKE MICHIGAN ON TUESDAY...RAIN WILL BE LIKELY IN A CONCENTRATED
BAND OF ISENTROPIC LIFT EXTENDING SOUTHEAST FROM THE LOW CENTER.

ENERGY WILL TRANSFER TO A COASTAL LOW ON WEDNESDAY...LEAVING THE
AREA IN A BRISK AND COLDER NORTHWEST FLOW OF DECREASING MOISTURE AND
FORCING. THIS WILL BRING AN END TO STEADY RAIN AND SNOW...WITH
SCATTERED SNOW SHOWERS THEN LINGERING INTO THURSDAY. NORTHERN
LOCATIONS SEEM TO HAVE THE BEST CHANCE FOR LIGHT SNOW ACCUMULATIONS.

AFTER NEAR NORMAL HIGHS AROUND 40 ON SUNDAY...WARM ADVECTION AHEAD
OF THE LOW WILL ALLOW ABOVE NORMAL HIGHS IN THE 40S ON MONDAY AND
TUESDAY. EXPECT EARLY HIGHS NEAR 40 ON WEDNESDAY...DROPPING TO
BELOW NORMAL 30S UNDER COLD ADVECTION ON THURSDAY.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL ALLOW FOR DRY CONDITIONS ACROSS THE TAF SITES
THROUGH THE TAF PERIOD. MVFR TO VFR CIGS CAN BE EXPECTED
THROUGH THE TAF PERIOD. SOME BRIEF MVFR VSBYS WILL BE POSSIBLE
OVERNIGHT. ONLY INCLUDED MVFR VSBYS AT KCMH WHERE THERE IS A
BETTER CHANCE OF THEM OCCURRING.

OUTLOOK...MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE ON
SATURDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$

SYNOPSIS...HICKMAN/NOVAK
NEAR TERM...HATZOS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...CONIGLIO
AVIATION...NOVAK






AREA FORECAST DISCUSSION

NWS TULSA OK

 906 PM CST SAT DEC 20 2014

.UPDATE...

PATCHY DRIZZLE WAS ADDED TO THE EVENING FORECAST...SEE DISCUSSION BELOW.

&&

.DISCUSSION...

A FEW HOLES IN THE STRATUS DECK DEVELOPED DURING THE DAY...BUT THE
CLOUDS HAVE FILLED BACK IN AT ALMOST ALL LOCATIONS /COPAN WILL
CLOUD UP SOON/ AS OF 03Z. CLOUDS WILL HANG ON THRU THE
NIGHT...CONTINUING A STRING OF CLOUDY DAYS AND NIGHTS THAT
STRETCHES BACK TO THE 17TH. AS SUCH...LOWS WILL NOT BE MUCH
DIFFERENT FROM TODAY`S HIGHS AND THE FORECAST IS WITHIN REASON OF
THE LATEST HRRR GUIDANCE. IN ADDITION...WEAK WARM ADVECTION IN THE
LOW LEVELS IS PROVIDING JUST ENOUGH LIFT FOR PATCHY
DRIZZLE...WHICH SHOWS UP ON RADAR AND IN SOME OF THE METAR OBS.
THEREFORE...HAVE ADDED PATCHY DRIZZLE THRU THE NIGHT TO THE GRIDS. NO
OTHER CHANGES ARE PLANNED TO THE FORECAST THIS EVENING.

LACY

&&

.PREV DISCUSSION... /ISSUED 525 PM CST SAT DEC 20 2014/

AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LOW CLOUDS WILL PERSIST THROUGH THE ENTIRE FORECAST
PERIOD. MVFR CONDITIONS EARLY THIS EVENING WILL TRANSITION TO IFR
AS CEILINGS LOWER AND VISIBILITY EVENTUALLY BECOMES REDUCED
OVERNIGHT...SOME AREAS LIKELY TO SEE A PERIOD OF LIFR CEILINGS AS
WELL 12-18Z. MODEST IMPROVEMENT AFTER 18Z SUNDAY.

PREV DISCUSSION... /ISSUED 348 PM CST SAT DEC 20 2014/

DISCUSSION...
ANOTHER CLOUDY DAY FOR TSA CWA. CLOUDS LIKELY ANCHORED
FOR ANOTHER COUPLE OF DAYS BEFORE SUN ARRIVES ON 24TH.
MAX / MIN TEMP ADJUSTMENTS MADE FOR MAINLY CLOUDY SKY.

H500 WAVE  FROM WESTERN CANADA WILL DROP INTO NORTHERN
&  CENTRAL PLAINS OVER THE NEXT COUPLE OF DAYS AS WEST
COAST H500 RIDGE AMPLIFIES. ELONGATED TROUGH - CENTRAL
CANADA TO TEXAS BY TUESDAY.  THIS EVOLUTION WILL BRING
CHANCE PRECIP MONDAY THROUGH TUESDAY.  ECMWF WRF GFS &
DIFFER SOME WITH THIS SYSTEM. OF PARTICULAR CONCERN IS
HOW FAST  COLD AIR WILL ARRIVE IN EASTERN OK NORTHWEST
AR TUESDAY. IF THE COLD AIR ARRIVES EARLY THE TAIL END
OF PRECIPITATION LATE TUESDAY/TUESDAY NIGHT WOULD BE A
WINTRY MIX. GIVEN THAT THE BEST CHANCE FOR PRECIP WILL
BE TUESDAY WITH  HIGH TEMPS IN LOW/MID 40S DID NOT PUT
POSSIBLE WINTRY MIX IN UNTIL TUESDAY NIGHT. AND...THEN
JUST SLIGHT CHANCE EXTREME EASTERN OK AND NORTHWEST AR.

RIDGE MOVES ACROSS THE REGION CHRISTMAS DAY WHILE NEXT
UPPER WAVE DIVES FROM PACIFIC NORTHWEST TO THE ROCKIES.
CHRISTMAS DAY  PROMISES TO OFFER LOTS OF SUN WITH HIGH
TEMPERATURES ABOVE NORMAL IN THE 50 TO 60 DEGREE RANGE.

COLD FRONT WILL SWEEP THROUGH CHRISTMAS NIGHT / FRIDAY
LEAVING BELOW AVERAGE TEMPS NEXT WEEKEND.           GW


&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   41  50  46  54 /   0  10  10  20
FSM   40  50  43  56 /   0  10  10  30
MLC   42  50  47  57 /  10  10  10  20
BVO   37  48  43  53 /   0  10  10  20
FYV   36  46  42  53 /   0  10  10  30
BYV   35  47  41  53 /   0  10  10  30
MKO   40  49  44  55 /   0  10  10  20
MIO   39  48  43  52 /   0  10  20  30
F10   40  49  45  56 /  10  10  10  20
HHW   42  50  45  60 /  10  10  10  10

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

$$

LONG TERM....30





AREA FORECAST DISCUSSION...UPDATED

NWS ABERDEEN SD

 543 PM CST SAT DEC 20 2014

.UPDATE...
DROPPED OVERNIGHT LOWS NEAR PIERRE A COUPLE OF DEGREES. OTHERWISE
FORECAST APPEARS TO BE ON TRACK AND NO FURTHER CHANGES ARE PLANNED.

SEE UPDATED AVIATION DISCUSSION BELOW.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT

LOW CLOUDS AND FOG WILL ONCE AGAIN BE THE RULE OVERNIGHT AS A VERY
MOIST LOW LEVEL AIR MASS REMAINS IN PLACE. BEEN CLOSELY FOLLOWING
THE HRRR LOW-LEVEL CLOUD COVER PRODUCT WHICH HAS BEEN DOING AN
AMAZING JOB WITH HANDLING STRATUS DECKS THE PAST SEVERAL EVENTS.
IT BASICALLY SHOWS THE STRATUS CLOUDS REMAINING IN PLACE ALL NIGHT
WITH A SLIGHT WESTWARD PUSH ONCE AGAIN ON ITS WESTERN EDGE. WILL
GO WITH PERSISTENCE FORECAST CONCERNING THE FOG AS IT HAS BEEN
OCCURRING THE PAST FEW NIGHTS UNDERNEATH THE STRATUS...SO NO
REASON WHY IT WONT HAPPEN AGAIN...AND IN FACT WIDESPREAD LIGHT FOG
IS ALREADY IN PLACE...WITH LOCALLY THICKER FOG. SEEMS THE MOIST
LAYER IS TOO SHALLOW FOR ANY MEANINGFUL FREEZING DRIZZLE TO OCCUR
OVERNIGHT BUT SOMETHING TO KEEP AN EYE ON ANYWAY.

ON SUNDAY...EXPECTING LOW CLOUDS TO HANG IN TOUGH ACROSS THE EAST
ONCE AGAIN WITH NO REAL SIGNALS FROM ANYTHING TO CLEAR THEM OUT.
WILL ALSO BE WATCHING ARRIVAL OF THE LOW PRESSURE SYSTEM WHICH
WILL ENTER THE DAKOTAS BY SUNDAY EVENING...THEN MOVE INTO WESTERN
MINNESOTA AND IOWA REGION BY MONDAY NIGHT. MODELS STILL HAVING A
TOUGH TIME HANDLING THIS SYSTEM IN REGARDS TO STRENGTH MAINLY.
THEY REALLY DO NOT KNOW HOW TO HANDLE THE EVENTUAL CLOSING OFF AND
SUBSEQUENT MOVEMENT OF THE UPPER LOW...AND ITS ASSOCIATED MOISTURE
AVAILABILITY. THIS WILL BE KEY IN FIGURING OUT JUST HOW MUCH WRAP
AROUND PRECIPITATION WE RECEIVE. BASICALLY TOOK A BLENDED APPROACH
FOR RIGHT NOW WHICH STILL LEAVES THE AREA WITH A COUPLE INCHES OF
SNOW AND SOME MIXED PRECIP IN THE FORM OF FREEZING RAIN AND SLEET
TO START THINGS OFF SUNDAY EVENING. THERMAL PROFILES EVENTUALLY
GET COLD ENOUGH BY MONDAY TO CHANGE THINGS OVER TO SNOW. STILL
HAVE MANY DOUBTS AND LOW CONFIDENCE IN EXACTLY JUST HOW THIS
SYSTEM WILL EVOLVE AND HOW MUCH MOISTURE WILL REALLY BE ASSOCIATED
WITH IT. HAVE A FEELING MODELS MAY NOT LATCH ON TO A MORE
DEFINITIVE SOLUTION UNTIL SOMETIME SUNDAY.


.LONG TERM...TUESDAY THROUGH SATURDAY
LOW PRESSURE WILL BE EAST OF THE REGION WHEN THE PERIOD STARTS
WITH THE POTENTIAL FOR LINGERING SNOW SHOWERS...MAINLY ACROSS THE
EASTERN PART OF THE CWA THROUGH THE DAY TUESDAY. A DECENT PRESSURE
GRADIENT ACROSS THE AREA MAY RESULT IN BREEZY TO WINDY CONDITIONS
AS WELL. WEAK HIGH PRESSURE THEN MOVES IN WITH DRY CONDITIONS
EXPECTED WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM LOOKS TO TRACK
ACROSS THE CENTRAL PLAINS ON THURSDAY...BUT THE MODELS ARE NOT IN
VERY GOOD AGREEMENT WITH STRENGTH OR TIMING. THE GFS AND ECMWF
AGREE SOMEWHAT ON THE TIMING WITH THE GEM BEING MUCH SLOWER.
HOWEVER...THE GFS BRINGS LITTLE IN THE WAY OF
PRECIPITATION...WHILE THE ECMWF PLASTERS MOST OF THE STATE, FOR
NOW...WILL STICK FAIRLY CLOSE TO THE SUPERBLEND KEEPING SCHC/CHC
POPS MAINLY ACROSS THE SOUTHERN CWA THURSDAY INTO THE DAY FRIDAY.
HIGH PRESSURE WILL MOVE BACK IN AFTER THAT WITH DRY CONDITIONS
FRIDAY NIGHT THROUGH THE DAY SATURDAY.

SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE FOR THE FIRST
HALF OF THE PERIOD...WITH HIGHS MAINLY IN THE MID 20S TO LOWER 30S
TUESDAY...WEDNESDAY AND THURSDAY. COOLER AIR THEN MOVES IN BEHIND
THE STORM SYSTEM...WITH HIGHS IN THE TEENS AND 20S FRIDAY AND
SATURDAY.



&&

.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

IFR CIGS WILL REMAIN FIRMLY IN PLACE ACROSS THE EASTERN HALF OF
THE CWA THROUGH THE TAF PERIOD. UNDER THE LOW CLOUDS...VSBYS WILL
GENERALLY BE MVFR IN FOG THROUGH THIS EVENING...BUT THERE WILL
LIKELY BE PERIODS OF IFR VSBYS AGAIN OVERNIGHT AND INTO EARLY
SUNDAY MORNING...AFFECTING KABR AND KATY. VFR CONDITIONS WILL
PREVAIL ACROSS THE WESTERN HALF OF THE CWA WITH JUST SOME HIGH
CLOUDS STREAMING OVERHEAD.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...WISE

WEATHER.GOV/ABERDEEN







AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 538 PM CST SAT DEC 20 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014

MUCH OF THE SAME EXPECTED TONIGHT INTO TOMORROW WITH THE LOW
CLOUDS HANGING TOUGH OVER A MAJORITY OF THE AREA. DO NOT REALLY
EXPECT THE CLEARING LINE TO MOVE MUCH THROUGH TOMORROW...WITH ONLY
GREGORY...BRULE AND PORTIONS OF CHARLES MIX COUNTIES SEEING ANY
CLEARING AND SUN. SIGNAL THAT THE DENSER FOG MAY ENCOMPASS MORE OF
THE AREA TONIGHT...MAKING IT TO AROUND THE INTERSTATE 29 CORRIDOR.
SO WILL HAVE TO KEEP AN EYE ON THIS...FOR NOW INCREASED MENTION OF
FOG IN THE GRIDS. GFS AND RAP SUGGEST LOW LEVEL MOISTURE DEPTH WILL
INCREASE TONIGHT AHEAD OF A WEAK UPPER WAVE THAT CROSSES THE REGION.
THIS HAPPENS MAINLY ACROSS PORTIONS OF NORTHWEST IOWA FROM SIOUX
CITY TO SPENCER. SO COULD POTENTIALLY SEE SOME PATCHY DRIZZLE OR
FREEZING DRIZZLE IN THAT AREA...BUT ANYTHING SHOULD BE LIGHT.

GIVEN THE CLOUD COVER...DIURNAL RANGE OF TEMPERATURES WILL BE SMALL.
WILL NOT FALL MUCH TONIGHT...WITH UPPER 20S TO LOW 30S EXPECTED.
THEN ON SUNDAY WE WILL ONLY WARM UP SEVERAL DEGREES...WITH 30S
ACROSS MOST OF THE REGION. WILL START TO BECOME A BIT BREEZY OUT OF
THE SOUTH BY LATER SUNDAY...WITH GUSTS AROUND 25 MPH EAST OF THE
JAMES RIVER.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014

PRECIPITATION LIKELY TO DEVELOP ON SUNDAY...WITH THE BETTER CHANCES
IN THE EASTERN CWA. WHILE THE MAIN WARM FRONT IS TO THE NORTH OF THE
AREA...THE PV ANOMOLY AND COLD FRONT ALOFT SWING THROUGH SUNDAY
NIGHT AND SHOULD ALLOW WHAT WILL BE MAINLY RAIN. THE NORTHERN AND
WESTERN CWA COULD SEE SOME MIXED PRECIPITATION BUT THE CHANCES FOR
PRECIPITATION A LITTLE LOWER IN THESE LOCATIONS SO HOPEFULLY LITTLE
OR NO ACCUMULATION. TEMPERATURES REMAIN PRETTY MILD THROUGH THE
NIGHT AS WELL WITH LOW PRESSURE WRAPPING UP TO THE NORTH AND WEST OF
THE AREA SO MAINLY SOUTHERLY OR WESTERLY FLOW. LOWS GENERALLY FROM
THE LOWER TO MIDDLE 30S.

LOOKS LIKE EVERYONE SHOULD WARM TO AT LEAST THE MID 30S ON MONDAY
WITH LOWER 40S LIKELY IN PARTS OF NORTHWEST IOWA. THE DAYTIME
CHANCES FOR PRECIPITATION SHOULD NOT BE REAL HIGH AND WILL KEEP MOST
LOCATIONS IN THE CHANCE CATEGORY AS THE AREA WAITS FOR THE WRAP
AROUND TO SET UP LATE MONDAY AFTERNOON INTO MONDAY NIGHT. RIGHT NOW
LOOKING LIKE MAINLY A RAIN TO SNOW TRANSITION WITH LITTLE CHANCE FOR
SLEET AND FREEZING RAIN MONDAY AND MONDAY NIGHT.

THE CHANCE FOR SNOW WILL LINGER INTO TUESDAY BUT AMOUNTS WILL REMAIN
FAIRLY MINIMAL. WHEN ALL IS SAID AND DONE LOOKING AT ABOUT A HALF AN
INCH TO AN INCH OVER NORTHWEST IOWA TO 2 TO 3 INCHES FROM HURON TO
MARSHALL. A WAVE TRACKS THROUGH TO THE NORTH OF THE AREA ON TUESDAY
WHICH WILL BRING SOME DRYING ALOFT AND BRING AN END TO THE THREAT
FOR PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY.

THE UPPER LEVEL PATTERN REMAINS FAIRLY ACTIVE THROUGH THE EXTENDED
PERIOD WITH ONE WAVE EXITING ON WEDNESDAY AND ANOTHER MOVING INTO
THE AREA FRIDAY INTO SATURDAY. STILL SOME DECENT DIFFERENCES FOR THE
INCOMING SYSTEM SO NOT OVERLY CONFIDENT ON WHAT TO EXPECT BUT RIGHT
NOW LOOKS COLD ENOUGH FOR ALL SNOW...JUST A MATTER OF WHETHER OR NOT
THIS IS A SYSTEM THAT MOVES THROUGH RATHER QUICKLY OR ONE THAT TAKES
ON JUST A TOUCH OF NEGATIVE TILT LIKE THE ECMWF SUGGESTS AND BRINGS
IN A BETTER CHANCE FOR HEAVIER AMOUNTS. UNFORTUNATELY NO WAY TO
REALLY FIGURE THIS OUT RIGHT NOW SO WILL CONTINUE TO CARRY A CHANCE
OF SNOW THURSDAY NIGHT INTO SATURDAY. FOR NOW WEDNESDAY AND THURSDAY
LOOK MAINLY DRY WITH SLIGHTLY BELOW NORMAL HIGH TEMPERATURES THROUGH
THE PERIOD. OVERNIGHT LOWS WILL LIKELY BE AT OR ABOVE NORMAL DURING
THIS TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 538 PM CST SAT DEC 20 2014

POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE PERIOD...WITH
IFR TO LIFR CIGS AND VIS LIKELY. NOT REALLY EXPECTING MUCH CHANGE
FROM THE CURRENT CONDITIONS...SO MAINLY WENT WITH A PERSISTENCE
FORECAST. SOME SIGNS THAT DENSER FOG AND LIFR CIGS WILL SPREAD A BIT
FURTHER EAST TONIGHT TOWARD INTERSTATE 29 AND INTO HIGHER ELEVATIONS
OF SOUTHWEST MN TONIGHT. STRONGER BOUNDARY LAYER WINDS DEVELOP BY
SUNDAY AFTERNOON...WHICH COULD HELP LIFT CEILINGS INTO MVFR RANGE
FOR A FEW HOURS TOWARD THE END OF THE TAF PERIOD.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH




AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 1050 PM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 830 PM CST THU DEC 18 2014

WITH THE CLOUD DECK HANGING IN THE NEIGHBORHOOD OF 1000-1500
FEET...THE CLOUD DECK IS RELATIVELY SHALLOW AND WILL BE DIFFICULT
TO GET DROPLET PRODUCTION. HAVE THEREFORE REMOVED PRECIP THROUGH
THE OVERNIGHT...HOWEVER...AM STILL CONCERNED ABOUT FOG POTENTIAL
ACROSS SOUTH CENTRAL SOUTH DAKOTA. BOTH HI RES HRRR AND THE RAP
SUGGEST FOG POTENTIAL...SO HAVE RAISED FOG MENTION AFTER 06Z
WELL INTO FRIDAY MORNING ALONG THE MISSOURI RIVER VALLEY IN
CENTRAL SOUTH DAKOTA.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 348 PM CST THU DEC 18 2014

STRATUS CURRENTLY COVERING THE ENTIRE REGION...AND THINK THE CLOUDS
STAY LOCKED IN THROUGH THE NIGHT AND INTO TOMORROW. CLEARING LINE IN
CENTRAL SOUTH DAKOTA WILL PROBABLY APPROACH OUR FAR WESTERN AREAS
SUCH AS GREGORY AND BRULE COUNTIES. SO COULD SEE SOME CLEARING THERE
LATER TONIGHT...AND SOME SUN IN THOSE LOCATIONS TOMORROW. THIS IS
THE AREA THAT COULD SEE SOME FOG DEVELOPMENT LATER TONIGHT IF THEY
ARE ABLE TO CLEAR...SO ADDED IN FOG MENTION. THE REST OF THE AREA
WILL STAY LOCKED IN THE LOW CLOUDS THROUGH TOMORROW...WITH NOTHING
ABLE TO SCOUR OUT THE LOW LEVEL MOISTURE. GIVEN THE CLOUD
COVER...RAISED LOWS TONIGHT...AS DO NOT THINK TEMPERATURES WILL BE
ABLE TO FALL MORE THAN A FEW DEGREES FROM CURRENT READINGS.

ONE QUESTION IS WHETHER WE ARE ABLE TO GET ANY FLURRIES OUT OF THE
STRATUS TONIGHT. MODELS SUGGEST MOISTURE LAYER DEEPENS ENOUGH FOR
THIS TO BE A POSSIBILITY...BUT MOISTURE DEPTH AND SATURATION BOTH
SEEM BORDERLINE. EXPECT CLOUD TOP TEMPERATURES TO BE RIGHT AROUND
-7C TO -10C...RIGHT ON THE EDGE OF ICE PRODUCTION. THUS CAN NOT RULE
OUT A LITTLE LIGHT FREEZING DRIZZLE AS WELL. MOISTURE DEPTH LOOKS TO
DECREASE FROM WEST TO EAST THROUGH THE NIGHT...SO THINK THE LIGHT
PRECIP THREAT SHOULD WANE BY MORNING. WILL NEED TO KEEP AN EYE ON
THINGS...BUT AT THIS TIME THINK THAT EVEN IF WE DO GET FREEZING
DRIZZLE...IT WILL NOT BE HEAVY ENOUGH TO CAUSE MUCH OF AN ISSUE.
OTHERWISE CLOUDY BUT SLIGHTLY WARMER CONDITIONS TOMORROW. CLOUDS
WILL PREVENT US FROM WARMING TOO MUCH...BUT STILL THINKING WE GET
INTO THE LOW TO MID 30S.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 348 PM CST THU DEC 18 2014

MOIST LOW LEVEL FLOW WILL CONTINUE TO BRING LOW STRATUS TO THE BULK
OF THE FORECAST AREA FRIDAY NIGHT THROUGH SATURDAY NIGHT. SOME
DECEASE IN CLOUD COVERAGE WILL BE POSSIBLE ON SATURDAY...
PARTICULARLY IN THE WEST WHERE TEMPERATURES WILL QUICKLY WARM INTO
THE MID AND UPPER 30S AND MAY SOAR EVEN HIGHER IF SUBSTANTIAL
CLEARING DOES OCCUR. WITHOUT MUCH LIFT IN THE CLOUD
LAYER...MEASURABLE PRECIPITATION IS NOT EXPECTED. CANNOT RULE OUT
SOME PATCHY DRIZZLE/FREEZING DRIZZLE POTENTIAL...BUT WITH CLOUD TOPS
TOO WARM FOR ICE CRYSTAL GROWTH...FLURRIES ARE NOT EXPECTED. MODEL
SOUNDINGS SUGGEST THAT THE CLOUD DEPTH IS A BIT TOO MARGINAL FOR
WIDESPREAD DRIZZLE OR FREEZING DRIZZLE...WITH THE EXCEPTION OF PARTS
OF NORTHWEST IOWA ON SATURDAY NIGHT. SURFACE TEMPERATURES WILL BE IN
THE UPPER 20S AT THIS TIME...SO WILL LEAVE MENTION OF PATCHY
FREEZING DRIZZLE.

POTENT STORM SYSTEM BEGINS TAKING SHAPE OVER THE NORTHERN PLAINS
SUNDAY AFTERNOON AS A TROUGH EMERGES FROM THE CANADIAN ROCKIES AND
DIGS INTO NORTH DAKOTA. STILL LOOKING AT SOME FAIRLY SIGNIFICANT
MODEL DIFFERENCES REGARDING THE TRACK AND TIMING...SO CONFIDENCE IN
TEMPERATURE TRENDS AND PRECIPITATION TIMING IS SOMEWHAT LOW. IT DOES
LOOK LIKE AN INITIAL WAVE SWINGS INTO THE AREA SUNDAY NIGHT...WITH
THE GEM AND NAM AROUND 6 TO 12 HOURS FASTER THAN THE ECMWF AND GFS.
WITH THIS WAVE SOME BROAD LIFT NOSES INTO THE AREA AND SHOULD ALLOW
SOME LIGHT PRECIPITATION TO FORM MAINLY ACROSS THE EASTERN HALF.
SURFACE TEMPERATURES COOL WHILE THE MILD AIR ALOFT ERODES. EXPECT A
WINTRY MIX OF PRECIPITATION...WITH SNOW...SLEET AND FREEZING RAIN
POSSIBLE. WITH THE BETTER FORCING LIKELY TO OUR EAST...ANY
PRECIPITATION WILL BE VERY LIGHT AND PRELIMINARILY IT LOOKS LIKE
SNOW AND ICE AMOUNTS WOULD BE VERY MINIMAL.

SECONDARY WAVE FOLLOWS QUICKLY ON MONDAY...SLOWS AND DEEPENS OVER
THE MID AND NORTHERN MISSISSIPPI VALLEY INTO MONDAY NIGHT. THE GEM
IS THE OUTLIER WITH A WEAKER OPEN WAVE AND WAS THEREFORE DISCARDED.
THE LATEST GFS AND ECMWF ARE QUITE A BIT FURTHER EAST WITH THE LOW
CENTER COMPARED TO PREVIOUS RUNS. IT SLOWLY WOBBLES OFF TO THE EAST
THROUGH TUESDAY NIGHT WITH LIGHT PRECIPITATION IMPACTING OUR AREA ON
THE BACK SIDE OF THE LOW. WITH A MORE EASTERN TRACK...THE BEST
POTENTIAL FOR PRECIPITATION FOR US WILL BE ACROSS OUR EASTERN HALF
MONDAY INTO TUESDAY. COOLER AIR ADVECTING INTO THE AREA BEHIND THE
LOW WILL ALLOW THE RAIN AND SNOW MIX ON MONDAY TO SWITCH ENTIRELY TO
SNOW MONDAY NIGHT. WINDS WILL ALSO PICK UP FROM THE NORTHWEST MONDAY
NIGHT AND TUESDAY AND BECOME QUITE BREEZY. HIGHS ON MONDAY WILL BE
MILD IN THE 30S...AND COOL SLIGHTLY INTO THE UPPER 20S TO MID 30S ON
TUESDAY.

STRATUS CLOUDS STICK AROUND THE REGION WEDNESDAY WITH ANOTHER
POSSIBLE WEAK WAVE DIVING ALONG THE UPPER LEVEL NORTHWEST FLOW.
SLIGHT CHANCE OF LIGHT SNOW WILL ACCOMPANY THIS WAVE ACROSS OUR
NORTHEASTERN HALF. COOLER TEMPERATURES FILTER BACK INTO THE REGION
MID WEEK DROPPING READINGS BACK BELOW NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1040 PM CST THU DEC 18 2014

CLOUDS WILL AGAIN STRUGGLE TO MOVE OUT OF THE AREA INTO FRIDAY.
LATEST RAP/NAM CONTINUE TO HOLD SUB 2K FT CEILINGS IN THE FSD/SUX
TERMINALS WELL INTO FRIDAY. FURTHER WEST...A BIT MORE QUESTIONS
EXIST AS THE EDGE OF STRATUS MAY APPROACH HON BY DAYBREAK. MORE
CONCERNING IS THE POTENTIAL FOR FOG AND VLIFR STRATUS TO DEVELOP
ON THE EDGE OF THE THICKER CLOUD DECK AND MOVE INTO HON FOR MUCH
OF THE MORNING.

WILL ADVERTISE NO IMPROVEMENT FOR THE SECOND HALF OF THE TAF
GIVEN WEAK FLOW AND LINGERING MOISTURE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...
SHORT TERM...CHENARD
LONG TERM...
AVIATION...DUX



AREA FORECAST DISCUSSION

NWS MORRISTOWN TN

 316 PM EST FRI DEC 19 2014

.SHORT TERM...(TONIGHT AND SATURDAY)...
THERE REMAINS MUCH UNCERTAINTY IN THE SHORT TERM PERIOD DUE TO LARGE
DIFFERENCES BETWEEN THE NAM AND THE GFS. THE NAM IS THE WETTER AND
COLDER OF THE TWO MODELS. THE PREFERENCE IS MORE TOWARD THE GFS DUE
TO THE PRECIP/CONVECTION THAT IS EXPECTED TO DEVELOP ALONG THE GULF
COAST...PROVIDING A STABILIZING EFFECT UPSTREAM AND PREVENTING
NORTHWARD MOISTURE ADVECTION. THE RAP APPEARS TO AGREE WITH THIS
SCENARIO...AND THE LATEST SREF APPEARS TO BE TRENDING DOWNWARD IN
POPS/QPF.

AS A RESULT...WILL CONFINE LIKELY POPS TO EXTREME SOUTHERN PORTIONS
OF THE AREA TONIGHT...FADING TO LOW CHANCE POPS NORTH. QPF WILL BE
LIGHT...UP TO A TENTH OF AN INCH SOUTH AND IN THE MOUNTAINS. IN
HIGHER ELEVATIONS...MAINLY ABOVE 2500 FT...THE PRECIP SHOULD BE
MOSTLY SNOW...BUT WITH A SMALL WINDOW OF ADEQUATE MOISTURE DEPTH
INTO THE DENDRITE GROWTH ZONE AND WEAK LIFT...NO MORE THAN ONE INCH
IS EXPECTED TO ACCUMULATE. TRI-CITIES AND SW VA COULD SEE SOME SNOW
IF THE COLDER NAM IS CORRECT...BUT THE WARMER GFS LOOKS LIKE ALL
RAIN. WILL MENTION RAIN OR SNOW IN THAT AREA AS A COMPROMISE...WITH
WITH NO ACCUMULATIONS. THE FASTER EXIT OF PRECIP SHOWN BY THE GFS
WILL BE FOLLOWED...ENDING POPS IN THE EARLY AFTERNOON.

.LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...
A WEAK SYSTEM WILL BE EXITING TO THE NE SATURDAY NIGHT WITH SKY
CONDITIONS IMPROVING TO PARTLY CLOUDY. UPPER FLOW IS ZONAL WITH
DRIER AIR MASS AND WEAK HIGH PRESSURE SETTLING OVER THE REGION.
THE SURFACE HIGH WILL BE OVERHEAD SUNDAY WITH SKIES PARTLY TO
MOSTLY SUNNY AND HIGH TEMPERATURES SLIGHTLY ABOVE NORMAL IN THE
UPPER 40S TO MID 50S. ANOTHER SOUTHERN SYSTEM DEVELOPS ACROSS THE
GULF COAST SUNDAY AND BRINGS CLOUDS AND RAIN ACROSS THE FORECAST
AREA SUNDAY NIGHT AND MONDAY. AFTER A BRIEF BREAK IN THE STEADY
RAIN MONDAY NIGHT A MUCH STRONGER SYSTEM STILL LOOKS ON TRACK TO
MOVE INTO THE MS VALLEY MONDAY. A DEEP TROUGH OVER THE CENTRAL
STATES WILL MOVE INTO THE EASTERN STATES TUESDAY AND WEDNESDAY. A
STRONG COLD FRONT APPROACHES THE FORECAST AREA TUESDAY NIGHT INTO
WEDNESDAY. A SURFACE LOW DEEPENS OVER OH WEDNESDAY. THE SYSTEM
FINALLY SHIFTS EAST OF THE AREA ON CHRISTMAS DAY. THERE COULD BE
SOME THUNDERSTORMS IF ENOUGH INSTABILITY DEVELOPS TUESDAY AFTERNOON
AND EVENING AHEAD OF THE FRONT. MUCH COLDER TEMPERATURES WEDNESDAY
AND THURSDAY BEHIND THE FRONT. AS COLDER AIR MOVES IN LATE
WEDNESDAY AND WEDNESDAY NIGHT SOME MINOR SNOWFALL ACCUMULATIONS ARE
POSSIBLE IN THE HIGHER ELEVATIONS.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             36  51  36  54 /  70  20   0  10
KNOXVILLE MCGHEE TYSON AIRPORT, TN  34  45  33  52 /  40  30   0  10
OAK RIDGE, TN                       33  45  33  51 /  40  20   0  10
TRI CITIES AIRPORT, TN              31  43  30  49 /  40  40  10   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DGS/TD



AREA FORECAST DISCUSSION

NWS AMARILLO TX

 1104 PM CST THU DEC 18 2014

.AVIATION...
FOR THE 06Z TAFS...MVFR TO IFR CEILINGS ACROSS THE OKLAHOMA AND
TEXAS PANHANDLES ARE EXPECTED TO REMAIN THROUGH MUCH OF FRIDAY
MORNING. HOWEVER....FOG HAS BEEN SLOW TO DEVELOP. HAVE KEPT MENTION
OF IFR FOG IN TAF SITES THOUGH CONFIDENCE IS WANING THAT VISIBILITIES
WILL DROP THAT LOW. IFR TO MVFR STRATUS DECK WILL REMAIN INTO THE
AFTERNOON BEFORE SLOWLY SCATTERING OUT MID-LATE DAY. CONFIDENCE IS
NOT HIGH ENOUGH TO ADD IN PRECIPITATION AT THIS TIME...AND SHOULD
MAINLY BE CONFINED EAST OF THE TAF SITES TODAY.

ELSENHEIMER

&&

.PREV DISCUSSION... /ISSUED 248 PM CST THU DEC 18 2014/

DISCUSSION...

PRIMARY WEATHER IMPACTS DURING THE NEXT SEVEN DAYS WILL BE IN THE
SHORT TERM WITH PRECIPITATION CHANCES TONIGHT AND POTENTIAL FOR FOG
ONCE AGAIN. MAIN ADJUSTMENT TO THE FORECAST WAS TO TRY AND BE MORE
DETERMINISTIC WITH PRECIPITATION TYPE OVERNIGHT ALTHOUGH THAT
REMAINS A CHALLENGE GIVEN MARGINAL THERMAL PROFILES FOR FROZEN
PRECIPITATION IN MODEL FORECAST SOUNDINGS. INITIAL CONCERNS ARE FOG
POTENTIAL LATER TONIGHT AS LOW LEVEL FLOW BECOMES MORE EASTERLY AND
STRENGTHENS. MOISTURE OVER SOUTHWEST OKLAHOMA AND WESTERN NORTH
TEXAS WILL ADVECT WESTWARD AND UPSLOPE. HAVE INCLUDED AREAS OF FOG
IN THE GRIDS. LOCALLY DENSE FOG WILL AGAIN BE POSSIBLE.

WV LOOP AND 500 MB RAP ANALYSIS CLEARLY SHOWED A SHORTWAVE TROUGH
OVER EASTERN ARIZONA MOVING EASTWARD. SHORT TERM MODELS ARE IN GOOD
AGREEMENT ON THE TIMING AND STRENGTH OF THIS WAVE AS IT MOVES TOWARD
WEST TEXAS TONIGHT AND CROSSES THE REGION TOMORROW MORNING. THE
PERIOD OF BEST OMEGA/SATURATION IN THE DEDRITIC GROWTH ZONE WILL BE
AFTER ABOUT 03Z IN THE WEST SPREADING EASTWARD OVERNIGHT AND LASTING
THROUGH ABOUT 15Z IN THE EAST. JUST BELOW THE DGZ IS A LAYER OF DRY
AIR THAT WILL TAKE SOME TIME TO SATURATE THUS DELAYING THE ONSET OF
PRECIPITATION UNTIL CLOSER TO MIDNIGHT IN THE WEST/CENTRAL AND AFTER
MIDNIGHT IN THE EAST. THE BIGGEST CHALLENGE FOR CONVEYING SENSIBLE
WEATHER IN THIS FORECAST WILL BE THE TEMPERATURE PROFILE. AT LEAST
SHORT RANGE MODELS AGREES FAIRLY WELL. THE DEPTH OF THE ABOVE
FREEZING WET BULB TEMPERATURES IS SUFFICIENT FOR ALL RAIN ACROSS
MOST OF THE AREA...ESPECIALLY THE FAR SOUTHEAST. HAVE TRENDED
PRECIPITATION TYPE TO MORE RAIN AS A RESULT. INCREASED QPF SLIGHTLY
IN THE FAR SOUTHEAST.

QUITE A BIT OF UNCERTAINTY DEVELOPS BY EARLY NEXT WEEK AND CONTINUES
THROUGHOUT THE EXTENDED PERIOD. VERY POWERFUL PACIFIC JET NOSES INTO
THE CENTRAL ROCKIES BY MONDAY EAST OF A SIGNIFICANT MEAN RIDGE OVER
THE EASTERN PACIFIC. A VERY STRONG TROUGH HAS BEEN SHOWN TO DEVELOP
OVER THE EASTERN UNITED STATES. THIS SHOULD HAPPEN BY AROUND
CHRISTMAS EVE OR CHRISTMAS DAY BUT MEDIUM RANGE MODELS STRUGGLE WITH
HOW IT EVOLVES EARLY/MID WEEK ONCE PACIFIC JET MOVES INTO THE
CENTRAL CONUS. NEW 12Z EMCWF IS QUICKER WITH DEVELOPING A CLOSED LOW
WHILE THE GFS IS MORE PRONOUNCED WITH INDIVIDUAL SHORTWAVES
TRAVERSING THE DEEPENING UPPER TROUGH. THE GFS BECOMES DEEPER BY
WEDNESDAY WITH MORE SUBSTANTIAL HEIGHT RISES ON ITS WEST SIDE OVER
THE PLAINS. EXACT IMPLICATIONS FOR US ARE UNCLEAR. WILL NEED TO
WATCH THE POTENTIAL FOR A DOWNSLOPING WARMING/WIND EVENT ON MONDAY.
GFS/MEX DEPICT THIS NOW. ECMWF IS MORE EXPANSIVE WITH HEIGHT FALLS
OVER THE CENTRAL CONUS GIVEN ITS MORE CONSOLIDATED/SPRAWLING
SOLUTION WITH LESS DISTINCT SHORTWAVES EMBEDDED WITHIN. GFS
SOUNDINGS SHOW DEEP MIXING INTO AN AREA OF STRONG FLOW ALOFT WHICH
RAISES SOME CONCERN OF NEAR ADVISORY CRITERIA WINDS IF THIS SOLUTION
VERIFIES. OTHERWISE DID NOT DEVIATE FROM MEDIUM RANGE CONSENSUS. ANY
PRECIPITATION IN THE EXTENDED SHOULD BE INSIGNIFICANT...AND
DIFFICULT TO TIME GIVEN MODEL DIFFERENCES.

BRB

PREV DISCUSSION... /ISSUED 1142 AM CST THU DEC 18 2014/

AVIATION...
FOR THE 18Z TAFS...THE MAIN WEATHER ELEMENTS FOR THIS FCST CYCLE WILL
BE LOW CLOUDS AND EPISODES OF FOG. FOG IS SLOWLY ERODING AT THE TAF
SITES AND SHOULD CONTINUE TO DO SO EARLY THIS AFTERNOON. IFR CIGS
WILL GRADUALY AND TEMPORARILY LIFT INTO THE MVFR CATEGORY AS WELL.
EXPECT THE RETURN OF IFR CIGS AND AREAS OF FOG AGAIN LATE TONIGHT
INTO FRIDAY MORNING. A FAST MOVING UPPER LEVEL STORM SYSTEM WILL
GRAZE THE REGION TONIGHT AND EARLY FRIDAY...AND MAY BRING SOME
SPRINKLES...LIGHT RAIN SHOWERS...FLURRIES...OR VERY LIGHT SNOW.
HOWEVER...THE CHANCE OF PRECIPITATION IS NOT VERY HIGH...SO HAVE
OPTED TO OMIT FROM THE TERMINAL FCSTS AT THIS TIME.

ANDRADE

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.

&&

$$

18/09





AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1133 AM CST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE MAIN FORECAST CHALLENGE INTO TONIGHT IS WITH THE LOW LEVEL
MOISTURE AND WHETHER IT WILL BE ENOUGH TO PRODUCE SOME FREEZING
DRIZZLE OR FLURRIES.

CURRENTLY...A BAND OF 1-2KFT STRATUS THAT EXTENDS FROM NORTHWEST
WISCONSIN DOWN THROUGH SOUTHERN WISCONSIN HAS BEEN PRODUCING SOME
FLURRIES DUE TO SOME WEAK LIFT ASSOCIATED WITH A COLD FRONT THAT
EXTENDS FROM SOUTHERN MICHIGAN WEST-NORTHWEST INTO WESTERN
WISCONSIN. THIS FEATURE WILL PULL EASTWARD THIS MORNING/AFTERNOON
AND SHOULD TAKE THESE FLURRIES EAST AS WELL. TO THE SOUTHWEST
TOWARD DES MOINES...ANOTHER BAND OF LOW LEVEL MOISTURE ASSOCIATED
WITH SOME RETURN SOUTHERLY FLOW/WARM AIR ADVECTION HAS FORMED SOME
FREEZING DRIZZLE AND FLURRIES IN THAT REGION. THE QUESTION FOR
TODAY/TONIGHT IS WHETHER THAT FREEZING DRIZZLE/FLURRIES HOLDS
TOGETHER.

19.00Z NAM/GFS AND 19.06Z RAP SOUNDINGS CERTAINLY SHOW THE SURFACE
TO 800MB LAYER MOISTENING UP THROUGH TONIGHT...ITS JUST A MATTER
OF WHETHER THERE IS ANY LIFT THERE. GIVEN THAT THERE CURRENTLY IS
SOME PRECIPITATION OCCURRING UPSTREAM...THERE DOES APPEAR TO BE
ENOUGH LIFT AND HAVE GONE AHEAD AND ADDED A MENTION OF SOME
PATCHY FREEZING DRIZZLE IN FOR TODAY IN SE MN/NE IA WITH IT
SPREADING EASTWARD OVERNIGHT AS THE MOISTURE SHIFTS EAST. DMX HAS
REPORTED SOME FLURRIES OCCURRING AS WELL AT THE MOMENT MEANING
THAT THERE IS SOME ICE BEING INTRODUCED IN THE LOW LEVELS THOUGH
MOST OF THE FORECAST SOUNDINGS SHOW THAT SATURATED LAYER BEING TOO
WARM TONIGHT TO PRODUCE ANY FLURRIES LOCALLY. NOT SURE WHETHER
THIS FREEZING DRIZZLE IS GOING TO BE ADVISORY WORTHY GIVEN THAT
THERE IS NOT MUCH FOCUS FOR LOW LEVEL LIFT...BUT CONDITIONS WILL
HAVE TO BE MONITORED SINCE AIR/ROAD TEMPERATURES WILL BE BELOW
FREEZING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE PATTERN BECOMES MORE ACTIVE GOING INTO THE LATER PORTION OF
THE WEEKEND ON INTO EARLY NEXT WEEK AS A SERIES OF MID LEVEL SHORT
WAVE TROUGHS PROPAGATE ON THROUGH. THE NEXT DECENT CHANCE FOR
PRECIPITATION APPEARS TO COME IN ON SUNDAY AS LOW LEVEL WARM AIR
ADVECTION WILL COMBING WITH SOME WEAK 700MB TROUGHING TO DEVELOP
SOME PRECIPITATION. PRECIPITATION TYPE IS TRICKY WITH THIS SYSTEM
AS THERE IS A WEAK WARM LAYER THAT REACHES +1 TO +2C AND WOULD
MELT SOME OF THE SNOW THAT FALLS THROUGH IT. THERE ALSO APPEARS
TO BE A DRY LAYER BETWEEN THE 700MB MOISTURE AND SURFACE/LOW LEVEL
MOISTURE WHICH BRINGS INTO QUESTION HOW DEEP THE LIFT REALLY WILL
BE. SURFACE TEMPERATURES WILL ALSO BE CLIMBING TOWARD AND ABOVE
FREEZING WHICH COMPLICATES HOW MUCH SNOW COULD ACCUMULATE. KEPT
SNOW ACCUMULATIONS ON THE LOW SIDE...HALF INCH OR LESS...GIVEN ALL
OF THE QUESTIONS WITH THIS ROUND OF PRECIP.

A DEEPER TROUGH DEVELOPS ACROSS THE DAKOTAS SUNDAY NIGHT INTO
TUESDAY AND WILL BRING A MORE WIDESPREAD SHOT OF
PRECIPITATION...MAINLY RAIN BEFORE CHANGING OVER TO SNOW ON THE
BACKSIDE TUESDAY. THE 19.00Z GFS/ECMWF ARE IN DECENT AGREEMENT
WITH THIS SYSTEM IN REGARD TO TIMING BUT ARE DIFFERENT WITH THEIR
PROGRESSION OF THE SURFACE LOW WITH THE GFS DIGGING DEEPER EARLIER
WITH THE ECMWF KEEPING PRECIPITATION AROUND A TAD LONGER. BOTH
MODELS HAVE THE SNOW OFF TO THE EAST BY CHRISTMAS DAY WITH JUST
SOME WEST TO NORTHWEST WINDS IN THE WAKE OF THE SYSTEM.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1133 AM CST FRI DEC 19 2014

IFR CEILINGS/MVFR VISIBILITY IN MIST IS STAYING JUST WEST OF
KRST/KLSE ACROSS MUCH OF CENTRAL MN/IA LATE THIS MORNING. LATEST
FORECAST GUIDANCE SUGGESTS THESE LOW CLOUDS WILL SLOWLY PUSH EAST
THROUGH THE PERIOD...BUT WITH A PREDOMINANT SOUTH WIND...DELAYED
ONSET OF LOWER CEILINGS AT KRST UNTIL 19.22Z AND AT KLSE UNTIL
20.03Z. PATCHY FREEZING DRIZZLE POSSIBLE OVERNIGHT...BUT COVERAGE
UNCERTAINTY PRECLUDES MENTION IN 19.18Z TAFS. WILL NEED TO WATCH
FOR A FURTHER LOWERING OF CEILINGS/VISIBILITY IN THE HOURS AROUND
DAYBREAK SATURDAY MORNING. OTHERWISE...CONDITIONS SHOULD REBOUND
SLIGHTLY NEAR THE END OF THE PERIOD. SOUTHERLY WINDS WILL
CONTINUE...GENERALLY 10 KTS OR LESS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ROGERS



AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 540 AM CST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE MAIN FORECAST CHALLENGE INTO TONIGHT IS WITH THE LOW LEVEL
MOISTURE AND WHETHER IT WILL BE ENOUGH TO PRODUCE SOME FREEZING
DRIZZLE OR FLURRIES.

CURRENTLY...A BAND OF 1-2KFT STRATUS THAT EXTENDS FROM NORTHWEST
WISCONSIN DOWN THROUGH SOUTHERN WISCONSIN HAS BEEN PRODUCING SOME
FLURRIES DUE TO SOME WEAK LIFT ASSOCIATED WITH A COLD FRONT THAT
EXTENDS FROM SOUTHERN MICHIGAN WEST-NORTHWEST INTO WESTERN
WISCONSIN. THIS FEATURE WILL PULL EASTWARD THIS MORNING/AFTERNOON
AND SHOULD TAKE THESE FLURRIES EAST AS WELL. TO THE SOUTHWEST
TOWARD DES MOINES...ANOTHER BAND OF LOW LEVEL MOISTURE ASSOCIATED
WITH SOME RETURN SOUTHERLY FLOW/WARM AIR ADVECTION HAS FORMED SOME
FREEZING DRIZZLE AND FLURRIES IN THAT REGION. THE QUESTION FOR
TODAY/TONIGHT IS WHETHER THAT FREEZING DRIZZLE/FLURRIES HOLDS
TOGETHER.

19.00Z NAM/GFS AND 19.06Z RAP SOUNDINGS CERTAINLY SHOW THE SURFACE
TO 800MB LAYER MOISTENING UP THROUGH TONIGHT...ITS JUST A MATTER
OF WHETHER THERE IS ANY LIFT THERE. GIVEN THAT THERE CURRENTLY IS
SOME PRECIPITATION OCCURRING UPSTREAM...THERE DOES APPEAR TO BE
ENOUGH LIFT AND HAVE GONE AHEAD AND ADDED A MENTION OF SOME
PATCHY FREEZING DRIZZLE IN FOR TODAY IN SE MN/NE IA WITH IT
SPREADING EASTWARD OVERNIGHT AS THE MOISTURE SHIFTS EAST. DMX HAS
REPORTED SOME FLURRIES OCCURRING AS WELL AT THE MOMENT MEANING
THAT THERE IS SOME ICE BEING INTRODUCED IN THE LOW LEVELS THOUGH
MOST OF THE FORECAST SOUNDINGS SHOW THAT SATURATED LAYER BEING TOO
WARM TONIGHT TO PRODUCE ANY FLURRIES LOCALLY. NOT SURE WHETHER
THIS FREEZING DRIZZLE IS GOING TO BE ADVISORY WORTHY GIVEN THAT
THERE IS NOT MUCH FOCUS FOR LOW LEVEL LIFT...BUT CONDITIONS WILL
HAVE TO BE MONITORED SINCE AIR/ROAD TEMPERATURES WILL BE BELOW
FREEZING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE PATTERN BECOMES MORE ACTIVE GOING INTO THE LATER PORTION OF
THE WEEKEND ON INTO EARLY NEXT WEEK AS A SERIES OF MID LEVEL SHORT
WAVE TROUGHS PROPAGATE ON THROUGH. THE NEXT DECENT CHANCE FOR
PRECIPITATION APPEARS TO COME IN ON SUNDAY AS LOW LEVEL WARM AIR
ADVECTION WILL COMBING WITH SOME WEAK 700MB TROUGHING TO DEVELOP
SOME PRECIPITATION. PRECIPITATION TYPE IS TRICKY WITH THIS SYSTEM
AS THERE IS A WEAK WARM LAYER THAT REACHES +1 TO +2C AND WOULD
MELT SOME OF THE SNOW THAT FALLS THROUGH IT. THERE ALSO APPEARS
TO BE A DRY LAYER BETWEEN THE 700MB MOISTURE AND SURFACE/LOW LEVEL
MOISTURE WHICH BRINGS INTO QUESTION HOW DEEP THE LIFT REALLY WILL
BE. SURFACE TEMPERATURES WILL ALSO BE CLIMBING TOWARD AND ABOVE
FREEZING WHICH COMPLICATES HOW MUCH SNOW COULD ACCUMULATE. KEPT
SNOW ACCUMULATIONS ON THE LOW SIDE...HALF INCH OR LESS...GIVEN ALL
OF THE QUESTIONS WITH THIS ROUND OF PRECIP.

A DEEPER TROUGH DEVELOPS ACROSS THE DAKOTAS SUNDAY NIGHT INTO
TUESDAY AND WILL BRING A MORE WIDESPREAD SHOT OF
PRECIPITATION...MAINLY RAIN BEFORE CHANGING OVER TO SNOW ON THE
BACKSIDE TUESDAY. THE 19.00Z GFS/ECMWF ARE IN DECENT AGREEMENT
WITH THIS SYSTEM IN REGARD TO TIMING BUT ARE DIFFERENT WITH THEIR
PROGRESSION OF THE SURFACE LOW WITH THE GFS DIGGING DEEPER EARLIER
WITH THE ECMWF KEEPING PRECIPITATION AROUND A TAD LONGER. BOTH
MODELS HAVE THE SNOW OFF TO THE EAST BY CHRISTMAS DAY WITH JUST
SOME WEST TO NORTHWEST WINDS IN THE WAKE OF THE SYSTEM.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM CST FRI DEC 19 2014

EXTENSIVE DECK OF MVFR CLOUD COVER IN PLACE ACROSS THE REGION.
THERE IS A THIN SLIVER OF VFR CLOUD CIGS EXTENDING FROM VCNTY KRST
SOUTHEASTWARD INTO NORTHEAST IA...BUT THINKING THIS WILL QUICKLY
FILL IN WITH MVFR CLOUD AS WELL THIS MORNING. IN ADDITION...SOME
PATCHY FREEZING DRIZZLE MAY SEEN ACROSS PORTIONS OF NORTHEAST IA
INTO SOUTHEAST MN BY MID-MORNING INTO THIS AFTERNOON AS SOUTHERLY
FLOW BRINGS MORE MOISTURE INTO THE AREA AHEAD OF A TROUGH OF LOW
PRESSURE MOVING OUT OF THE PLAINS.EXPECTING PATCHY FREEZING
DRIZZLE TO SPREAD EAST OF THE MISSISSIPPI LATER TONIGHT INTO
SATURDAY MORNING AS THE TROUGH MOVES INTO THE REGION. SINCE THIS
FREEZING DRIZZLE IS EXPECTED TO BE PATCHY IN NATURE...DECIDED TO
KEEP OUT OF THE BODY OF THE TAF FOR NOW...BUT WILL CONTINUE TO
MONITOR CLOSELY. OTHERWISE...LOOK FOR KRST CIGS TO SLIP FROM MVFR
TODAY INTO IFR AFTER 04Z.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS



AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 333 AM CST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE MAIN FORECAST CHALLENGE INTO TONIGHT IS WITH THE LOW LEVEL
MOISTURE AND WHETHER IT WILL BE ENOUGH TO PRODUCE SOME FREEZING
DRIZZLE OR FLURRIES.

CURRENTLY...A BAND OF 1-2KFT STRATUS THAT EXTENDS FROM NORTHWEST
WISCONSIN DOWN THROUGH SOUTHERN WISCONSIN HAS BEEN PRODUCING SOME
FLURRIES DUE TO SOME WEAK LIFT ASSOCIATED WITH A COLD FRONT THAT
EXTENDS FROM SOUTHERN MICHIGAN WEST-NORTHWEST INTO WESTERN
WISCONSIN. THIS FEATURE WILL PULL EASTWARD THIS MORNING/AFTERNOON
AND SHOULD TAKE THESE FLURRIES EAST AS WELL. TO THE SOUTHWEST
TOWARD DES MOINES...ANOTHER BAND OF LOW LEVEL MOISTURE ASSOCIATED
WITH SOME RETURN SOUTHERLY FLOW/WARM AIR ADVECTION HAS FORMED SOME
FREEZING DRIZZLE AND FLURRIES IN THAT REGION. THE QUESTION FOR
TODAY/TONIGHT IS WHETHER THAT FREEZING DRIZZLE/FLURRIES HOLDS
TOGETHER.

19.00Z NAM/GFS AND 19.06Z RAP SOUNDINGS CERTAINLY SHOW THE SURFACE
TO 800MB LAYER MOISTENING UP THROUGH TONIGHT...ITS JUST A MATTER
OF WHETHER THERE IS ANY LIFT THERE. GIVEN THAT THERE CURRENTLY IS
SOME PRECIPITATION OCCURRING UPSTREAM...THERE DOES APPEAR TO BE
ENOUGH LIFT AND HAVE GONE AHEAD AND ADDED A MENTION OF SOME
PATCHY FREEZING DRIZZLE IN FOR TODAY IN SE MN/NE IA WITH IT
SPREADING EASTWARD OVERNIGHT AS THE MOISTURE SHIFTS EAST. DMX HAS
REPORTED SOME FLURRIES OCCURRING AS WELL AT THE MOMENT MEANING
THAT THERE IS SOME ICE BEING INTRODUCED IN THE LOW LEVELS THOUGH
MOST OF THE FORECAST SOUNDINGS SHOW THAT SATURATED LAYER BEING TOO
WARM TONIGHT TO PRODUCE ANY FLURRIES LOCALLY. NOT SURE WHETHER
THIS FREEZING DRIZZLE IS GOING TO BE ADVISORY WORTHY GIVEN THAT
THERE IS NOT MUCH FOCUS FOR LOW LEVEL LIFT...BUT CONDITIONS WILL
HAVE TO BE MONITORED SINCE AIR/ROAD TEMPERATURES WILL BE BELOW
FREEZING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 333 AM CST FRI DEC 19 2014

THE PATTERN BECOMES MORE ACTIVE GOING INTO THE LATER PORTION OF
THE WEEKEND ON INTO EARLY NEXT WEEK AS A SERIES OF MID LEVEL SHORT
WAVE TROUGHS PROPAGATE ON THROUGH. THE NEXT DECENT CHANCE FOR
PRECIPITATION APPEARS TO COME IN ON SUNDAY AS LOW LEVEL WARM AIR
ADVECTION WILL COMBING WITH SOME WEAK 700MB TROUGHING TO DEVELOP
SOME PRECIPITATION. PRECIPITATION TYPE IS TRICKY WITH THIS SYSTEM
AS THERE IS A WEAK WARM LAYER THAT REACHES +1 TO +2C AND WOULD
MELT SOME OF THE SNOW THAT FALLS THROUGH IT. THERE ALSO APPEARS
TO BE A DRY LAYER BETWEEN THE 700MB MOISTURE AND SURFACE/LOW LEVEL
MOISTURE WHICH BRINGS INTO QUESTION HOW DEEP THE LIFT REALLY WILL
BE. SURFACE TEMPERATURES WILL ALSO BE CLIMBING TOWARD AND ABOVE
FREEZING WHICH COMPLICATES HOW MUCH SNOW COULD ACCUMULATE. KEPT
SNOW ACCUMULATIONS ON THE LOW SIDE...HALF INCH OR LESS...GIVEN ALL
OF THE QUESTIONS WITH THIS ROUND OF PRECIP.

A DEEPER TROUGH DEVELOPS ACROSS THE DAKOTAS SUNDAY NIGHT INTO
TUESDAY AND WILL BRING A MORE WIDESPREAD SHOT OF
PRECIPITATION...MAINLY RAIN BEFORE CHANGING OVER TO SNOW ON THE
BACKSIDE TUESDAY. THE 19.00Z GFS/ECMWF ARE IN DECENT AGREEMENT
WITH THIS SYSTEM IN REGARD TO TIMING BUT ARE DIFFERENT WITH THEIR
PROGRESSION OF THE SURFACE LOW WITH THE GFS DIGGING DEEPER EARLIER
WITH THE ECMWF KEEPING PRECIPITATION AROUND A TAD LONGER. BOTH
MODELS HAVE THE SNOW OFF TO THE EAST BY CHRISTMAS DAY WITH JUST
SOME WEST TO NORTHWEST WINDS IN THE WAKE OF THE SYSTEM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1026 PM CST THU DEC 18 2014

SOME CHANGES HAVE BEEN MADE TO THE PREVIOUS AVIATION FORECAST...
WHICH BEGUN ON A 0130Z AMENDMENT TO RST. MVFR STRATUS STILL
PERSISTS OVER THE TAF SITES. HOWEVER...A WEDGE OF DRY AIR BELOW AN
ALTOSTRATUS DECK HAS MADE ITS WAY FROM I-35 TOWARDS RST. RST
SHOULD GO VFR FOR THE START OF THE TAF PERIOD AS A SOUTHWEST WIND
AT THE HEIGHT OF THE CLOUDS PUSHES THE DRY AIR EASTWARD. IN
FACT...THIS DRYING COULD MAKE IT ALL THE WAY TO LSE LATER IN THE
MORNING...BETWEEN 15-19Z TO ALLOW FOR TEMPORARY SCATTERING OUT
THERE. LATE IN THE AFTERNOON...AROUND 20Z...MVFR STRATUS OVER
WESTERN IA AND MN LOOKS TO MOVE INTO RST. MEANWHILE...LIGHT FLOW
SHOULD ALLOW MVFR STRATUS TO REASSERT ITSELF AT LSE. ANTICIPATING
THEN CONDITIONS TO STAY MVFR INTO THE EVENING AS THE TWO STRATUS
DECKS MERGE UP.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ




AREA FORECAST DISCUSSION

NWS MELBOURNE FL

 412 AM EST SUN DEC 21 2014

.DISCUSSION...

...MORE HUMID AND WARMER THROUGH WED...
...INCREASED RAIN CHANCES LATE TODAY INTO MON THEN AGAIN LATE TUE
AND WED AHEAD OF NEXT COLD FRONT...

CURRENTLY...
STATIONARY FRONT LAYING INSIDE A WEAK INVERTED TROF EXTENDING FROM
THE SW GOMEX ACRS THE NRN FL PENINSULA. EVENING SOUNDINGS SHOW
INCRSG MOISTURE ACRS THE CENTRAL PENINSULA WITH PWAT VALUES ARND
1.4"...UP FROM 0.8" FROM THE 20/00Z FLIGHT...A FEW POCKETS OF DRY
AIR REMAIN BLO THE H70 LYR THAT INDICATE ADDITIONAL POTENTIAL FOR
MOISTURE LOADING. TO THE S...KMFL HAS MOISTENED TO 1.2" UP FROM 0.9"
FROM 20/00Z BUT STILL SHOWS THE REFLECTION OF A HIGH PRES RIDGE OVER
THE FL STRAITS AND THE CENTRAL BAHAMAS WITH SUBSTANTIAL DRY AIR ABV
A SUBSIDENCE INVERSION IN THE H80-H75 LYR. TO THE N...BOTH KJAX/KTAE
ARE NEARLY SATURATED THRU THE H100-H70 LYR WITH VERY DRY AIR ABV AN
INVERSION IN THE H70-H60 LYR. RUC ANALYSIS INDICATES PLENTIFUL
UPSTREAM MOISTURE WITH H100-H70 MEAN RH VALUES OVER THE GOMEX
LARGELY AOA 80PCT...H85-H50 VALUES AOA 50PCT BUT AS HIGH AS 90PCT
WITHIN THE VCNTY OF THE STATIONARY FRONT.

ALOFT...A 100-120KT ZONAL JET STREAK EXTENDING FROM THE RIO GRANDE
VALLEY TO BERMUDA IS PARALLEL TO THE STATIONARY FRONT AND IS
GENERATING A BROAD LINE OF UPR LVL DIVERGENCE. THOUGH THIS LINE HAS
MARGINAL STRENGTH/ORGANIZATION...VORTICITY AND OMEGA FIELDS SHOW
SIMILAR AXES...WITH ALL THREE NEARLY VERTICALLY STACKED. MODERATELY
COOL AIR REMAINS IN PLACE WITH H50 TEMPS HOLDING ARND -10C. H70-H50
LAPSE RATES STEEPEN FROM ARND 5.5C/KM OVER THE PENINSULA TO
6.0-6.5C/KM OVER THE ERN GOMEX...BUT H85-H70 LAPSE RATES ACTUALLY
DECREASE FROM ARND 5.5C/KM OVERHEAD TO 4.5C/KM UPSTREAM.

TODAY-TONIGHT...
THE ZONAL ORIENTATION OF THE JET WILL MAINTAIN A DEEP W/SW FLOW THRU
THE H85-H30 LYR THAT WILL REMAIN PARALLEL TO THE ORIENTATION OF THE
STATIONARY FRONT. THIS ASSURES THE FRONT WILL NOT MAKE MUCH PROGRESS
S OF THE I-4 CORRIDOR...IF EVEN THAT FAR. RUC40 ANALYSIS CONTINUES
TO SHOW A TIGHT E-W ISENTROPIC GRADIENT THRU THE 300K-315K LYR THAT
WILL COMBINE WITH THE DEEP W/SW FLOW TO EVENTUALLY PRODUCE THE NEXT
RAIN EVENT.

WITH MOST OF THE DRY AIR OVER CENTRAL FL ALREADY ERODED AND
PLENTIFUL MOISTURE UPSTREAM POISED TO PLOW WHAT REMAINS OUT OF THE
WAY...AND A WELL STACKED BAND OF INSTABILITY OVER THE GOMEX...POPS
WILL BE INTRODUCED TO THE ENTIRE CWA...SLGT CHC ALONG AND N OF
THE I-4 CORRIDOR THROUGH EARLY AFTN...BCMG 30-40 FROM VERO BEACH/LAKE
KISSIMMEE NWD. DRIER AIR AND FURTHER DISTANCE FROM THE FRONT WILL
LIMIT PRECIP OVER THE SRN CWA TO 20PCT...MAINLY IN -SHRAS.

PRECIP WILL INCREASE AREAWIDE TONIGHT...BUT AGAIN WILL REFLECT THE
DRIER AIR TO THE S AND THE POSITION OF THE STATIONARY FRONT. PRECIP
PRIMARILY WILL BE AS SHRAS...COOL AIR ALOFT ALONG WITH THE ENHANCED
BAND OF MID/UPR LVL INSTABILITY MAY ALLOW ISOLATED TSRA TO DVLP IN
THE VCNTY OF THE FRONTAL BNDRY. BOTH GFS/ECMWF MOS SHOWS HI POPS
OVER THE NRN CWA...THOUGH ECMWF IS TOO AGGRESSIVE WITH 70POPS CLEAR
DOWN TO LAKE OKEECHOBEE/JUPITER INLET. LIKELY/CATEGORICAL OVER THE
NRN BREVARD/NRN OSCEOLA NWD...SCT FROM SRN BREVARD/SRN OSCEOLA SWD.

ONE FLY IN THE OINTMENT IS THE GFS SOLUTION BTWN 06Z-12Z TONIGHT
WITH QPF BTWN 0.75"-1.5" ALONG THE I-4 CORRIDOR. TIME SECTIONS FOR
THE REGION SHOW VERY STRONG COUPLETS IN THE OMEGA AND DIVERGENCE
FIELDS IN THE PRESENCE OF 90PCT MEAN RH THRU THE ENTIRE H70-H30 LYR.
WHILE THE MOISTURE SOLUTION SEEMS REASONABLE...THE COUPLETS ARE
CLEAR SIGNS OF CONVECTIVE FEEDBACK. PRECIP CHANCES WILL BE HIGH...
NO DOUBT...BUT WILL CAP QPF BTWN 0.25"-0.50".

DESPITE INCREASING CLOUD COVER...LIGHT SRLY WINDS WILL COMBINE WITH
THE SLOW ARRIVAL OF SIG PRECIP TO ALLOW AFTN TEMPS TO WARM INTO THE
M/N70S AREAWIDE...NEAR 80 ALONG THE NE SHORE OF LAKE OKEECHOBEE...
4-8F ABV AVG. CLDY SKIES AND SFC DEWPOINTS IN THE U50S/L60S WILL
KEEP OVERNIGHT MINS IN THE L/M60S...EXCEPT IN THE M/U60S ALONG THE
IMMEDIATE COAST...10-15F ABV AVG.

MON-TUE...A MOIST SOUTHERLY WIND FLOW WILL BE IN PLACE WITH
FRONTAL BOUNDARY JUST TO OUR NORTH. TAIL END OF A BAND OF
CONVECTION NEAR THIS FRONTAL BOUNDARY MAY BE AFFECTING NORTHERN
SECTIONS EARLY MON THEN AS THE BOUNDARY GRADUALLY LIFTS NORTH...
NO LARGE SCALE LIFTING MECHANISMS ARE NOTED. LIKELY POPS IN THE
NORTH MON WILL TAPER BACK TO 30-40 PERCENT TUE. POPS ACROSS THE
SOUTH LOOK TO JUST BE AROUND 20 PERCENT BOTH DAYS. WITH THE HIGH
MOISTURE...THERE WILL PLENTY OF CLOUDINESS...ESPECIALLY MON. MAX
TEMPS SHOULD BE IN THE MID 70S NORTH ON MON AND LOWER 80S SOUTH.
THE LOWER 80S SHOULD LIFT TO CENTRAL SECTIONS ON TUE.

TUE NIGHT-CHRISTMAS...TROUGH IN THE MID SECTION OF THE COUNTRY
WILL DEEPEN WITH BASED DIGGING INTO THE GULF OF MEXICO WED THEN
DAMPENING OUT AS IT LIFTS ACROSS THE SOUTHEAST STATES ON CHRISTMAS.

THIS LATEST MODEL SOLUTION IS SLOWER THAN PREVIOUS RUNS...SO HAVE
BACKED OFF ON PRE FRONTAL CONVECTION UNTIL LATE TUE NIGHT IN THE
NORTH AND ON WED FOR THE REST OF THE AREA. RATHER STRONG LOW LEVEL
WINDS ARE STILL INDICATED AS THE CONVECTIVE BAND MOVES ACROSS THE
AREA. THE ECMWF 850 MB WINDS ARE STRONGER THAN THE GFS (WHICH HAS
BACKED TO AROUND 35 KNOTS). IN ANY EVENT...WITH THE SLOWER
SOLUTION...MODEST DIURNAL HEATING/DESTABILIZATION ON WED COULD
LEAD TO SOME STRONG STORMS.

SHOWER CHANCES MAY LINGER INTO WED NIGHT AND SOME CLOUDINESS INTO
CHRISTMAS MORNING. TEMPS DO NOT LOOK AS COOL WITH THE SLOWER
FRONTAL PASSAGE AND SOME CLOUDINESS. CONSENSUS LOWS ARE NOW IN THE
LOWER/MID 50S WITH HIGHS CHRISTMAS DAY IN THE MID 60S TO LOWER
70S...AND THESE READINGS MAY EVEN BE TOO COOL.

FRI-NEXT SUNDAY...HIGH PRESSURE BEHIND THE COLD FRONT IS FORECAST TO
EXTEND ACROSS THE AREA FRI AND ELONGATE INTO THE ATLANTIC NEXT
WEEKEND. THE MODELS DISAGREE ON TIMING OF THE NEXT COLD FRONT WITH
CONSENSUS SOLUTION SHOWING IT APPROACHING BY SUN (MOST SUPPORTED
BY THE ECMWF). THE GFS SMEARS 15-20 POPS OUT SAT-SUN BUT WILL HOLD
OFF THROWING IN 20 PERCENT UNTIL SUNDAY. AFTER TEMPS CLOSE TO
NORMAL ON FRI...MODERATION TO A LITTLE ABOVE NORMAL IS EXPECTED ON
THE WEEKEND.

&&

.AVIATION...THRU 22/06Z

SFC WNDS:
THRU 21/15Z...VRBL AOB 4KTS. BTWN 21/15Z-21/18Z...S 5-8KTS. BTWN
21/18Z-21/22Z...INTERIOR SITES S/SW 4-7KTS...COASTAL SITES S/SE
6-9KTS. AFT 21/22Z...S/SE AOB 5KTS.

VSBYS:
THRU 21/14Z...AREAS MVFR IN BR...LCL LIFR IN FG MNLY VCNTY
KVRB/KFPR. BTWN 21/14Z-21/18Z...N OF KEVB-KISM SLGT CHC MVFR SHRAS.
BTWN 21/18Z-22/03Z...N OF KMLB-KLAL SCT MVFR/ISOLD IFR SHRAS...S OF
KMLB-KLAL SLGT CHC MVFR SHRAS. AFT 22/03Z...N OF KTIX-KISM
PREVAILING MVFR IN NMRS/WDSPRD RA WITH PDS IFR +RA...S OF KTIX-KISM
CHC MVFR SHRAS.

CIGS:
N OF KMLB-KLAL: THRU 21/14Z...BTWN FL080-100 WITH PDS MVFR BTWN
FL020-030. BTWN 21/14Z-22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN
FL015-025 IN SCT SHRAS. AFT 22/03Z...MVFR BTWN FL010-020.

S OF KMLB-KLAL: THRU 21/14Z...AOA FL120. BTWN 21/14Z-22/03Z...BTWN
FL080-100 WITH PDS MVFR BTWN FL020-030 IN ISOLD -SHRAS. AFT
22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN FL015-025 IN SCT -SHRAS.

&&

.MARINE...
TODAY-TONIGHT...FAVORABLE SEA CONDS THRU DAYBREAK BUT DETERIORATING
WX CONDS AS A WEAK STATIONARY FRONT JUST N OF THE I-4 CORRIDOR
KEEPS THE LCL PGRAD DISRUPTED AND SERVES AS A FOCUS FOR SHRA/TSRA
ACTIVITY. SFC WNDS S-SE BTWN 4-8KTS FROM CAPE CANAVERAL SWD...VRBL
AOB 5KTS N OF THE CAPE IN THE VCNTY OF THE FRONT. SEAS AOB 2FT...
BUILDING TO 2-3FT OVER THE OFFSHORE LEG AFT MIDDAY.

N OF THE CAPE...SCT SHRAS AFT MIDDAY...BCMG NMRS/WDSPRD WITH ISOLD
TSRAS AFT SUNSET. S OF THE CAPE...ISOLD/SCT SHRAS AFT MIDDAY...CONTG
THRU THE OVERNIGHT PD.

MON-WED...SOUTHERLY FLOW WITH 10-15 KNOT SPEEDS INDICATED MON THEN
PUSHING UP TO 15-20 KNOTS TUE AFTERNOON AND EVENING AND NEAR 20
KNOTS WED AS COLD FRONT APPROACHES. SHOWER AND STORM CHANCES MAY
BE 50-60 PERCENT IN THE NORTH MON...THEN DROP OFF TO 20-40 PERCENT
UNTIL FRONTAL BAND CONVECTION APPROACHES LATE TUE NIGHT AND ON WED.

CHRISTMAS...STILL A LITTLE BIT OF A TRICKY FORECAST AS THE GFS IS
A LITTLE SLOWER THAN THE ECMWF WITH THE TIMING OF FRONTAL PASSAGE.
IF THE FRONT IS SLOWER LIKE THE GFS...THE BAND OF SHOWERS/STORMS
MAY STILL BE ACROSS THE WATERS EARLY...BUT OTHERWISE A NORTHWEST
WIND SURGE 15-20 KNOTS IS INDICATED BEHIND THE FRONT...SO BOATING
CONDITIONS DO NOT LOOK GOOD WITH EITHER MODEL.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  74  66  76  65 /  40  80  60  40
MCO  77  64  77  64 /  40  70  50  30
MLB  77  67  77  67 /  30  40  40  20
VRB  77  68  79  66 /  20  30  30  20
LEE  76  63  76  64 /  40  80  60  40
SFB  76  63  76  64 /  40  80  60  30
ORL  76  64  76  65 /  40  70  50  30
FPR  77  69  80  66 /  20  30  30  20

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&

$$

SHORT TERM...BRAGAW
LONG TERM....LASCODY




AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 310 AM EST SUN DEC 21 2014

.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CURRENTLY UNAMPLIFIED
UPPER LEVEL PATTERN ACROSS THE CONUS. FLOW IS MAINLY ZONAL ALONG THE
EASTERN SEABOARD DOWN TO THE FLORIDA PENINSULA...BUT WATCHING A
BROAD UPSTREAM TROUGH EJECTING EASTWARD ACROSS THE SOUTHERN PLAINS.
ENERGY FROM THE BASE OF THIS TROUGH WILL QUICKLY MOVE EASTWARD
ACROSS THE NORTHERN GULF COAST DURING THE NEXT 24 HOURS AND INTERACT
WITH A SURFACE FRONT ACROSS THE SAME REGION TO BRING INCREASING RAIN
CHANCES TO THE CENTRAL AND NORTHERN FLORIDA PENINSULA. HOWEVER...FOR
MOST OF US...THAT WILL NOT BE UNTIL MUCH LATER TODAY OR
TONIGHT...AND WILL DISCUSS IN MORE DETAIL WITHIN THE SHORT TERM
SECTION BELOW.

FURTHER UPSTREAM WE SEE STRONG UPPER JET ENERGY ARRIVING OVER THE
PACIFIC NORTHWEST COAST. IT WILL BE THIS ENERGY THAT EVOLVES INTO A
SIGNIFICANT PATTERN AMPLIFICATION/DEEP TROUGH THROUGH THE CENTRAL
PORTION OF THE COUNTY BY TUESDAY. IN RESPONSE TO THIS AMPLIFYING
TROUGH...THE DOWNSTREAM RIDGE OVER THE WESTERN ATLANTIC IS ALSO
PROGGED TO UNDERGO A SIGNIFICANT AMPLIFICATION. NEEDLESS TO
SAY...THE UPPER LEVEL PATTERN WILL HAVE LITTLE RESEMBLANCE TO THIS
MORNING WITHIN ONLY A COUPLE SHORT DAYS.

LOWER LEVELS...A QUASI-STATIONARY SURFACE FRONTAL BOUNDARY IS
LOCATED FROM THE CENTRAL GULF OF MEXICO NORTHEASTWARD TO THE
NORTHERN FLORIDA PENINSULA. RETURN FLOW IN THE LOWER LEVELS FROM THE
SOUTH IS DEVELOPING IN RESPONSE TO THE APPROACH OF THE UPPER WAVE TO
THE WEST. THIS FLOW IS BEGINNING TO UNDERGO ISENTROPIC UPGLIDE ALONG
THE 295-305K SURFACES...AND WE CAN SEE MORE AND MORE LOWER/MID LEVEL
CLOUDS BREAKING OUT ACROSS THE EASTERN GULF AND FL PENINSULA THIS
MORNING. THIS UPGLIDE HAS BEEN MAXIMIZED TO THE NORTH OF THE FRONT
ALONG WITH DECENT SURFACE FOCUS. REGIONAL RADAR HAVE BEEN SHOWING
AREAS OF SHOWERS DEVELOPING ACROSS THE FL PANHANDLE/NE GULF AS A
RESULT. SO FAR...MUCH OF THIS ACTIVITY HAS BEEN REMAINING TO OUR
NORTH...BUT WILL SEE A TENDENCY FOR THE SHOWERS TO MIGRATE TOWARD
THE NATURE COAST AS WE HEAD THROUGH THE DAY.

&&

.SHORT TERM (TODAY THROUGH MONDAY)...
MUCH OF THE FORECAST AREA WILL SEE A DRY MORNING AS ATMOSPHERIC
MOISTENING AS A RESULT OF LARGE SCALE UPGLIDE WILL BE SLOW TO
OCCUR...AND ANY ADDED SURFACE CONVERGENCE AS A RESULT OF SURFACE
WARM FRONT WILL BE CONFINED TO OUR FAR NORTHERN ZONES. WILL BRING A
LOW SHOWER CHANCE INTO LEVY/CITRUS COUNTIES THIS MORNING...BUT
ELSEWHERE POPS WILL BE 10% OR LESS. SKIES WILL BE MOSTLY
CLOUDY...ALTHOUGH BETTER CHANCES FOR PERIODS OF SUN WILL EXIST SOUTH
OF THE TAMPA BAY REGION. APPROACHING UPPER LEVEL ENERGY WILL
INCREASE ITS INTERACTION WITH THE SURFACE BOUNDARY DURING THE SECOND
HALF OF THE DAY...AND ESPECIALLY INTO THE EVENING HOURS. SURFACE
PRESSURE PATTERN WILL SHARPEN ACROSS THE NORTHEAST GULF OF MEXICO
INCREASING THE LOW LEVEL CONVERGENCE/FOCUS...AND BY LATE IN THE
DAY...THIS SHOULD COMBINE WITH CONTINUED UPGLIDE AND A DEVELOPING
FAVORABLE RRQ COUPLED JET PATTERN ALOFT TO PRODUCE INCREASING
SHOWERS COVERAGE INTO THE NATURE COAST ZONES. NWP ENSEMBLE MEMBERS
ARE NOT IN COMPLETE AGREEMENT WITH THE PLACEMENT OF THE LIFTING
FEATURES...AND THEREFORE HAVE SOMEWHAT DIFFERENT QPF PATTERNS. THE
NAM CONTINUE TO BE FURTHEST NORTH WITH THE BEST LIFT...WHILE THE
GFS...AND ESPECIALLY THE ECMWF SHOW BETTER SHOWER COVERAGE SOUTHWARD
INTO WEST-CENTRAL FLORIDA. THE NEW 21/03Z SREF ENSEMBLE MEAN HAS
TRENDED TOWARD THE GLOBAL MODELS WITH DECENT QPF NOW DOWN TO THE I-4
CORRIDOR. SO...AS SEEMS TO OFTEN BE THE CASE...THE MOST UNCERTAINTY
IN THE RAIN PROBABILITY FORECAST LATE TODAY INTO TONIGHT WILL BE
THROUGH THE TAMPA BAY/I-4 CORRIDOR...AND THE TIGHTEST POP GRADIENT
WILL BE ACROSS THIS REGION. WILL HAVE HIGH END LIKELY TO CATEGORICAL
POPS ANYWHERE NORTH OF I-4...WITH LIKELY POPS THROUGH THE TAMPA BAY
REGION...AND THEN QUICKLY DECREASE RAIN CHANCES FURTHER SOUTH AND
SOUTHEAST. WITH RESPECT TO THE ECMWF/GFS HAVE GONE WITH A 30-40%
CHANCE NEAR THE COAST DOWN TO SARASOTA/CHARLOTTE COUNTIES.

THE PLACEMENT OF THE UPPER JET IS MOST FAVORABLE FOR SIGNIFICANT
UPPER DIVERGENCE OVER THE NORTHERN HALF OF THE REGION TONIGHT. THE
GFS DIVERGENCE FIELDS ARE ACTUALLY QUITE IMPRESSIVE. MANY OF THE
MODELS SEEM TO BE PICKING UP ON THIS AND RAMPING UP QPF AMOUNTS
DURING THE OVERNIGHT HOURS. THEREFORE...THE POTENTIAL DOES APPEAR TO
EXIST FOR SOME PERIODS OF HEAVIER RAINFALL AFTER 00Z FROM TAMPA BAY
NORTHWARD THROUGH THE NATURE COAST. DUE TO THE INCREASED SYNOPTIC
LIFT IN THIS REGION (NORTH OF I-4) AND SHOWALTER INDICES AT OR BELOW
ZERO HAVE ADDED IN ISOLATED THUNDER TO THE FORECAST FOR ELEVATED
CONVECTION.

MONDAY...
EARLY MONDAY MORNING LOOKS TO BE JUST A CONTINUATION OF THE FORECAST
FROM TONIGHT...HOWEVER AS THE MORNING PROGRESSES WE SEE NOT ONLY THE
UPPER JET POSITION BECOME LESS FAVORABLE...BUT ALSO APPEARS THE LOW
LEVEL FRONT WILL BEGIN TO MOVE NORTHWARD AS A WARM FRONTAL FEATURE
AND REACH AT LEAST THE I-10 CORRIDOR BY EARLY AFTERNOON. THE LOSS OF
LARGE SCALE LIFT AND A DECREASE IN SURFACE FOCUS SHOULD RESULT IN
AREAS OF SHOWERS BECOME LESS ORGANIZED AND LIGHTER IN NATURE. RAMP
DOWN RAIN CHANCES THROUGH THE DAY...AND REMOVE ALL MENTION OF LIKELY
POPS (EVEN FOR THE NATURE COAST) BY THE AFTERNOON HOURS. RAIN
CHANCES ARE ACTUALLY LOOKING LESS AND LESS AS TIME GOES ALONG SOUTH
OF TAMPA BAY FOR MONDAY. IF WE CAN GET ENOUGH SUN TO BREAK
THROUGH THE CLOUDS...THE ATMOSPHERIC TEMP POTENTIAL IS GOING TO BE
VERY HIGH AND AFTERNOON HIGHS FOR THE SOUTHERN HALF OF THE FORECAST
AREA IN THE 80S MAY BECOME WIDESPREAD. TEMPS ARE MORE LIKELY TO BE
HELD IN THE 70S FROM TAMPA BAY NORTHWARD DUE TO MORE SHOWER AND
CLOUD POTENTIAL LATER INTO THE DAY.

&&

.LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...
MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE PERIOD. ONE UPPER
LOW/LONG WAVE TROUGH INITIALLY OVER THE MID CONUS MOVES EAST AND OFF
THE EASTERN SEABOARD BY THE END OF THE WEEK WITH A COLD FRONT
TRACKING INTO THE EASTERN GULF TUE THEN CROSSING FL WED. FOR THU
INTO SAT...RIDGING ALOFT AND SURFACE BUILDS INTO THE GULF AND SHIFTS
OVER THE STATE TO ATLANTIC WATERS. DURING SAT A SECOND LONG WAVE
TROUGH...A BIT LESS ROBUST THIS TIME...SLIDES FROM THE
MID-MISSISSIPPI VALLEY TO THE EAST STATES BY SUN WITH A COLD FRONT
SAGGING INTO FL.

THE UPPER TROUGH AMPLIFIES WITH INCREASING DEEP MOISTURE AS IT MOVES
ACROSS THE GULF THEN FL TUE AND WED. EXPECT AREAS OF SEA FOG TO
SPREAD SOUTHWARD DURING TUE...AND POSSIBLY BECOME LOCALLY DENSE...AS
LARGE AREAS OF CONVECTION MOVE ACROSS FROM NORTHWEST TO SOUTHEAST.
THERE WILL BE THE POTENTIAL FOR A FEW STRONG TO POSSIBLY SEVERE
STORMS. THE BULK OF THE CONVECTION WILL EXIT TO THE EAST WED
AFTERNOON AND EVENING. COOLER DRIER AIR WORKS IN DURING THU AND FRI
AS THE RIDGING MOVES BY. AS NOTED ABOVE THE NEXT UPPER TROUGH IS
WEAKER AND WILL HAVE LESS MOISTURE TO WORK WITH SO ONLY SLIGHT
CHANCE SHOWERS ARE EXPECTED...ACROSS THE NORTH SAT THEN SPREADING
INTO CENTRAL COUNTIES SUN. TEMPERATURES START OFF ABOVE NORMAL THEN
COOL THROUGH THE LAST PART OF THE WEEK BEFORE WARMING TO AROUND
NORMAL BY SUN. WINDS INCREASE INTO EXERCISE CAUTION/ADVISORY SPEEDS
LATE TUE AND WED AS THEY VEER FROM SOUTH TO WEST AND NORTH BEHIND
THE FRONT. WINDS DIMINISH DURING THU.

&&

.AVIATION...
GENERAL VFR CONDITIONS EARLY THIS MORNING UNDER PLENTY OF MID-LEVEL
CLOUDS. ALTHOUGH GUIDANCE IS HINTING OUT SOME FOG POTENTIAL FOR
KLAL/KPGD...THINKING THE CURRENT CLOUDS WILL PREVENT MUCH IN THE WAY
OF VIS RESTRICTIONS. GENERAL VFR CONDITIONS SHOULD PREVAIL THROUGH
THE DAYLIGHT HOURS WITH A LIGHT SOUTHEAST WIND SHIFTING SOUTH IN THE
AFTERNOON. PROBABILITY FOR SHOWERS WILL BE INCREASING DURING THE
LATE AFTERNOON AND EVENING HOURS FOR MAINLY KSRQ TO KTPA AND KLAL.
THE SHOWERS AND LOWER CLOUDS MAY RESULT IN PERIODS OF MVFR
RESTRICTIONS THROUGH THE OVERNIGHT HOURS INTO EARLY MONDAY MORNING.

&&

.MARINE...
A STATIONARY FRONTAL BOUNDARY IS LOCATED ACROSS THE NORTHERN
WATERS...JUST TO THE SOUTH OF CEDAR KEY EARLY THIS MORNING. WINDS
ARE EAST TO SOUTHEAST SOUTH OF THIS BOUNDARY AND FROM THE NORTHEAST
ON ITS NORTHERN SIDE. AREAS OF SHOWERS/RAIN EXPECTED TO INCREASE IN
COVERAGE OF THE MARINE AREA TO THE NORTH AND WEST OF TAMPA BAY
TODAY...SHOWERS REACHING FURTHER SOUTH TONIGHT. THE WARM FRONT IS
EXPECTED TO LIFT NORTH OF THE FORECAST WATERS FOR MONDAY WITH
SOUTHERLY FLOW HOLDING IN PLACE UNTIL A COLD FRONT CROSSES THE
REGION SOMETIME ON WEDNESDAY. WINDS WILL SHIFT NORTHWEST LATER
WEDNESDAY AND WEDNESDAY NIGHT AND POSSIBLY INCREASE TO ADVISORY
LEVELS FOR A TIME. WINDS AND SEAS QUICKLY DECREASE THURSDAY AND
FRIDAY AS HIGH PRESSURE BUILDS OVER THE REGION.

DEEP SOUTHERLY FLOW IS EXPECTED TO BRING CONDITIONS FAVORABLE FOR
SEA FOG TO DEVELOP IN THE NEXT SEVERAL DAYS. PATCHY FOG IS POSSIBLE
AS EARLY AS MONDAY...ESPECIALLY NORTH OF TARPON SPRINGS...HOWEVER...
THE SEA FOG IS ANTICIPATED TO BECOME MORE WIDESPREAD...AND EXTEND
FURTHER SOUTH MONDAY NIGHT INTO TUESDAY. ONCE FOG DEVELOPS IT IS
LIKELY TO LINGER INTO WEDNESDAY MORNING BEFORE A COLD FRONTAL
PASSAGE FINALLY CLEARS THE AREA. THE FOG IS ALSO ANTICIPATED TO
BECOME LOCALLY DENSE AT TIMES...ESPECIALLY TUESDAY AND TUESDAY
NIGHT.

&&

.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THROUGH MONDAY.
WETTING RAINFALL IS EXPECTED FROM TAMPA BAY NORTHWARD TONIGHT AND
MONDAY...WITH MORE SCATTERED NATURE SHOWERS FURTHER SOUTH. ANOTHER
ROUND OF WETTING RAINFALL FOR ALL ZONES IS EXPECTED LATER TUESDAY
NIGHT INTO WEDNESDAY WITH THE PASSAGE OF A COLD FRONT. DRIER WEATHER
WILL THEN RETURN FOR THURSDAY AND FRIDAY. LOCATIONS NEAR THE COAST
ARE ANTICIPATED TO SEE AREAS OF SEA FOG MOVE ASHORE...ESPECIALLY
TUESDAY INTO EARLY WEDNESDAY. THE FOG MAY BECOME LOCALLY DENSE AT
TIMES WITHIN A FEW MILES OF THE COAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  77  66  76  66 /  40  70  50  20
FMY  80  65  78  66 /  20  20  10  20
GIF  79  64  77  64 /  40  60  50  20
SRQ  77  65  76  65 /  30  50  40  20
BKV  77  64  77  64 /  50  80  70  30
SPG  76  65  74  66 /  40  70  50  20

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM...RUDE






AREA FORECAST DISCUSSION

NWS BOISE ID

 241 AM MST SUN DEC 21 2014

.SHORT TERM...TODAY THROUGH MONDAY...THE WARM FRONT IS FINALLY
SHOWING SIGNS OF PUNCHING NORTHWARD AS THE MODELS HAVE PROMISED.
BOGUS BASIN IS ABOVE FREEZING AND THE WEB CAM INDICATES RAIN. KMYL
IS STILL SNOWING...BUT SHOULD CHANGE TO RAIN SHORTLY. THE WSW WILL
BE ALLOWED TO EXPIRE AT 3 AM WITH THE MORNING FORECAST PACKAGE.
LIGHT TO MODERATE RAIN IS STILL FALLING OVER MOST OF THE REGION...
AND WE EXPECT IT TO CONTINUE FOR MUCH OF TODAY AS A WARM MOIST
FLOW REMAINS ENTRENCHED ALOFT. LATEST HRRR MODEL INDICATES A BREAK
THIS MORNING IN THE LOWER TREASURE VALLEY AND WESTERN PORTIONS OF
THE UPPER TREASURE VALLEY...INCLUDING BOISE. BUT THEN PRECIP
SPREADS BACK INTO THESE AREAS THIS AFTERNOON. THIS WILL HAVE A
STRONG IMPACT ON TEMPERATURES TODAY. WE HAVE LOWERED THE FORECAST
FOR THESE AREAS DUE TO HIGH-RESOLUTION MODEL DATA INDICATING
LESS WARMING THAN PREVIOUSLY EXPECTED TODAY. AS WE MOVE INTO
TONIGHT...SNOW LEVELS MOVE BACK DOWN AND MOISTURE WILL FINALLY
BEGIN TO DECREASE. THE CHANCE OF PRECIP DECREASES SHARPLY MONDAY
AND TEMPS WILL COOL FURTHER. WINDS WILL BE STRONG TODAY IN SE
OREGON...THE SOUTHWEST HIGHLANDS OF IDAHO...AND THE HIGHER TERRAIN
OF SRN TWIN FALLS COUNTY. THE WIND ADVISORY IS STILL ON TRACK TO GO
INTO EFFECT AT 8 AM MST AND RUN UNTIL 5 PM MST.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...CONDITIONS ARE
EXPECTED TO CONTINUE TO DRY OUT MONDAY NIGHT AND TUESDAY AS A
RIDGE OFF OF THE CALIFORNIA COAST AMPLIFIES. THIS WILL KEEP
TEMPERATURES ABOVE NORMAL. MODELS ARE IN GOOD AGREEMENT OF THE
RIDGE STARTING TO FLATTEN OUT ON WEDNESDAY AHEAD OF A TROUGH
MOVING IN FROM COASTAL BRITISH COLUMBIA. THE LATEST GFS AND ECMWF
RUNS HAVE BEGUN TO AGREE ON TIMING OF THIS TROUGH AND ASSOCIATED
COLD FRONT. PRECIP CHANCES WILL SPREAD FROM NW TO SE LATE WED
NIGHT WITH SNOW LEVELS AROUND 5000 FT DROPPING TO 2000 FT BY
EARLY CHRISTMAS MORNING. HOWEVER...THIS SYSTEM WILL LIKELY MOVE
OUT OF THE AREA QUITE QUICKLY SO CONDITIONS SHOULD DRY OUT ONCE
AGAIN CHRISTMAS AFTERNOON/EVENING. THE ASSOCIATED COLD FRONT WILL
BRING TEMPERATURES BACK TO NEAR NORMAL FOR THE REST OF THE PERIOD.
A COOLER NORTHWEST FLOW WILL SET IN FOR FRIDAY AND BEYOND.

&&

.AVIATION...VFR/MVFR CONDITIONS WITH RAIN AND HIGH ELEVATION SNOW
WILL CONTINUE THROUGH THE PERIOD. ISOLATED IFR CONDITIONS AND
MOUNTAIN OBSCURATION STILL EXIST IN THE WEST CENTRAL MOUNTAINS...
BUT AS THOSE AREAS TURN TO RAIN THIS MORNING...EXPECTING SOME
IMPROVEMENT IN VIS/CEILING. SURFACE WINDS WILL BE GENERALLY NW
WITH STRONGER GUSTS IN THE MAGIC VALLEY AND SOUTHWARD...AND
SOUTHEAST OREGON. WINDS ALOFT NEAR 10K FT...NW AT 50-70 KTS.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY FROM 8 AM THIS MORNING TO 5 PM MST THIS AFTERNOON
     IDZ015-029-030.
     WINTER WEATHER ADVISORY UNTIL 3 AM MST EARLY THIS MORNING IDZ011.
OR...WIND ADVISORY FROM 8 AM MST /7 AM PST/ THIS MORNING TO 5 PM MST
     /4 PM PST/ THIS AFTERNOON ORZ061-063.

&&

$$

WEATHER.GOV/BOISE

SHORT TERM...SP
LONG TERM....EP
AVIATION.....EP




AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1152 PM CST SAT DEC 20 2014

.UPDATE...
904 PM CST

WE STILL HAVE THE POSSIBILITY OF PATCHY FREEZING DRIZZLE
OVERNIGHT WITH THE BEST CHANCE IN OUR WESTERN AREAS.  THAT
SAID...TEMPERATURES ARE AROUND FREEZING AND NOT EXPECTED TO DROP
MUCH GIVEN THE CLOUD COVER AND WARM ADVECTION PATTERN SETTING UP.
AT THIS POINT IMPACTS DO LOOK MINIMAL...ESPECIALLY FARTHER EAST.  HAVE
KEPT TEMPS NEARLY STEADY OVERNIGHT. SOME PRECIPITATION MAY MAKE IT
CLOSER TO CHICAGO LATE TONIGHT INTO SUNDAY MORNING ONCE THE WARM
FRONT GETS CLOSER...BUT IT WOULD BE LARGELY IN THE FORM OF PATCHY
DRIZZLE. FOG MAY BE POSSIBLE AS WELL OVERNIGHT.

KMD

&&

.SHORT TERM...
247 PM CST

THROUGH SUNDAY NIGHT...

THE STREAK OF CLOUDY DAYS CONTINUES...WITH THE STUBBORN PATTERN TO
CONTINUE. AS A RESULT OF THE THICK CLOUD COVER...AND LACK OF
ORGANIZED ADVECTION OF ANY WARMER AIR AT THE SFC...TEMPS HAVE HELD
MAINLY ARND 30 TO 35 ACROSS THE BULK OF THE CWFA. SFC RIDGE
CONTINUES TO DRIFT EAST THIS AFTN...WITH A WEAK SOUTHERLY FLOW
DEVELOPING. THERE WAS A WEAK MID-LVL VORT LIFTING NORTHEAST ACROSS
SOUTHERN WISC/WESTERN LOWER MI...WHICH WAS ABLE TO PRODUCE A FEW
FLURRIES ACROSS THE FAR NORTHERN IL AREAS.

THIS AFTN/EARLY EVE LOOKS TO REMAIN QUIET/DRY...WITH A LIGHT
SOUTH/SOUTHEAST WIND. IR IMAGERY SHOWS THE NEXT WAVE ACROSS THE
CENTRAL PLAINS...WHICH IS PROGGED TO ARRIVE ACROSS NORTHWEST IL
AFTER MIDNIGHT. THERE APPEARS TO BE SOME WEAK ADVECTION OF MOISTURE
IN THE LOW-LEVELS OVERNIGHT. SOUNDINGS SUGGEST A NARROW WARM WEDGE
ALOFT WHICH COULD TRANSITION ANY PRECIP OVERNIGHT TO LIQUID. THE
FORCING/OMEGA IS RATHER WEAK...WHICH MAY LIMIT DROPLET SIZE AND
RESULT IN JUST PATCHY FREEZING DRIZZLE. TEMPS WILL LIKELY NOT MOVE
MUCH OVERNIGHT...SO HAVE HELD ONTO MID/UPR 20S OVERNIGHT.

LOCAL ARW8KM SOLUTION INDICATES THE MOISTURE TO BE RATHER MARGINAL
WITH THE SYSTEM ARRIVING OVERNIGHT/SUN MORNING...BUT PROGRESSIVE AND
LIFTING NORTH OF THE CWFA BY MIDDAY. WEAK THERMAL RIDGE AT 850MB
WOULD SUGGEST TEMPS MAY ACTUALLY WARM SUN AFTN...HOWEVER GIVEN THE
STUBBORN PATTERN WE HAVE BEEN IN WOULD LEAN TOWARDS NUDGING TEMPS
DOWN A DEGREE OR TWO. MOISTURE LAYER WILL REMAIN LOCKED IN ACROSS
THE REGION THRU SUN/SUN NGT. WITH A CONTINUED SOUTHERLY FLOW AT THE
SFC...TEMPS WILL LIKELY ONLY FALL TO ARND 30/LOW 30S.

BEACHLER

&&

.LONG TERM...
247 PM CST

MONDAY THROUGH SATURDAY...

500MB TROUGH BEGINS TO DIG INTO THE CENTRAL CONUS MON MORNING...WITH
WARM AIR STEADILY ADVECTING NORTH ACROSS THE FORECAST AREA. WHILE
THE THICK CLOUD COVER WILL PERSIST...THE PUSH OF WARM/MOIST AIR WILL
BRING TEMPS INTO THE 40S THE FAR SOUTHERN CWFA COULD SEE A FEW
LOCATIONS TOUCH THE UPR 40S MON AFTN. PRECIP WILL STEADILY PUSH EAST
AS THE UPPER LEVEL SYSTEM PROGRESSES TOWARDS THE REGION...BUT WITH
THE WARM AIR IN PLACE PRECIP SHUD FALL AS RAIN.

MON NGT THE 500MB VORT WILL SLIDE INTO THE UPPER MIDWEST...BUT THE
TROUGH WILL DIG SOUTH ACROSS THE SOUTHERN PLAINS. GUIDANCE HAS BEEN
INDICATING A SECONDARY SHORTWAVE EJECTING FROM THE TROUGH AXIS...AND
LIFTING IT NORTHEAST ACROSS THE TENN VALLEY CHRISTMAS EVE. THE
NORTHERN SFC LOW WILL BE WRAPPED UP ACROSS CENTRAL WISC TUE...WITH
THE MOIST CHANNEL FEEDING NORTH ACROSS THE FORECAST AREA THRU TUE
AFTN. THE SOUTHERN LOW WILL BE QUICKLY DEEPENING AS IT LIFTS NORTH
ACROSS THE OHIO VALLEY WED MORNING...ALLOWING WINDS TO BE ON THE
INCREASE AND HELPING TO STEADILY TRANSITION PRECIP OVER FROM RAIN TO
SNOW POST FROPA WED MORNING.

THE LAST SEVERAL CYCLES OF GUIDANCE HAVE DEMONSTRATED DIFFERENCES IN
PLACEMENT/TRACK OF THE SFC LOW WED AFTN/EVE. LATEST SOLUTION IS
PROGGED TO LIFT NORTH ACROSS NORTHERN IN AND THEN SLIGHTLY
RETROGRADE ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN WED EVE. THEN BY
CHRISTMAS DAY THE TROUGH WILL BE PIVOTING EAST AND HELPING TO LIFT
THE SFC LOW NORTHEAST AWAY FROM THE REGION. SOME WRAP AROUND
MOISTURE/SNOW LOOKS FAVORABLE WED NGT/THUR MORNING...BEFORE COMING
TO AN END JUST AFTER DAYBREAK CHRISTMAS MORNING. THIS SYSTEM WILL
CONTINUE TO BE CLOSELY MONITORED.

TEMPS WILL BE RETURNING TO MORE SEASONAL CONDS...WITH HIGHS
CHRISTMAS DAY IN THE LOW/MID 30S. FLOW REMAINS RATHER PROGRESSIVE
WITH ANOTHER WEAK PUSH OF WARMER AIR RETURNING FRI AND TEMPS BACK TO
THE UPR 30S/LOW 40S. THEN FOR FRI ENSEMBLES ARE INDICATING YET
ANOTHER TROUGH BEGINNING TO DIG INTO THE CENTRAL CONUS...WITH A SFC
LOW LIFTING NORTHEAST ACROSS THE WESTERN GREAT LAKES.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CEILINGS DEVELOPING PRE-DAWN AND LIKELY LINGERING THROUGH
  THE PERIOD.

* POTENTIAL FOR A PERIOD OF FOG/LIGHT FREEZING DRIZZLE THIS
  MORNING...THOUGH BETTER POTENTIAL WEST/NORTHWEST OF CHICAGO
  TERMINALS.

RATZER

//DISCUSSION...UPDATED 06Z...

LIGHT SOUTHWEST FLOW JUST ABOVE THE SURFACE IS ADVECTING LOW LEVEL
MOISTURE STEADILY NORTHEASTWARD ACROSS THE REGION...WITH EXPANSIVE
AREA OF MVFR/IFR/LIFR EXTENDING UPSTREAM TO THE WEST AND SOUTHWEST
OF NORTHERN ILLINOIS TERMINALS. MAIN MOIST AXIS AND LOWEST
CONDITIONS ALONG WITH FOG AND DRIZZLE/FREEZING DRIZZLE/FLURRIES
LIFTING FROM IOWA INTO NORTHWEST ILLINOIS...SETTING UP LIKELY IFR
CONDITIONS EARLY THIS MORNING FOR KRFD. FARTHER EAST...CHICAGO
AREA TERMINALS EXPECTED TO DETERIORATE TO MVFR BUT LOWER
CONDITIONS SHOULD REMAIN JUST OFF TO THE WEST/NORTHWEST. GIVEN
EXTENSIVE UPSTREAM CONDITIONS WOULD EXPECT LOW CLOUDS TO LINGER
THROUGH MUCH OF THE PERIOD AS SURFACE LOW PRESSURE DEVELOPING OVER
THE NORTHERN PLAINS MAINTAINS SOUTHWEST FLOW ALOFT.

SOUTH WINDS AROUND 5 KT WILL LIKELY BECOME A LITTLE EAST OF SOUTH
IN 170-160 DEGREE RANGE THROUGH THE DAY WITH SPEEDS INCREASING
INTO THE 10-15 KT RANGE. MODEL SOUNDINGS SUGGEST SOME GUSTS ABOVE
15 KT POSSIBLE LATER THIS AFTERNOON/TONIGHT...THOUGH SHALLOW MIXED
LAYER ARGUES AGAINST PREVAILING GUST MENTION.

RATZER


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* MEDIUM CONFIDENCE IN CEILING TRENDS THIS MORNING.

* LOW CONFIDENCE IN CEILING TRENDS THIS AFTERNOON/TONIGHT.

* LOW CONFIDENCE IN MVFR FOG AND DZ/FZDZ POTENTIAL THIS MORNING.

* MEDIUM-HIGH CONFIDENCE IN WINDS.

RATZER

//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...

MONDAY...MVFR/IFR EARLY LOWERING TO IFR/LIFR. RAIN DEVELOPING
LATE.

TUESDAY...ONCL SHRA. IFR PROBABLE.

WEDNESDAY...CHANCE SHRA/SHSN. MVFR LIKELY. IFR POSSIBLE.

THURSDAY...MVFR CIGS POSSIBLE EARLY.

FRIDAY...CHANCE OF RA/SN LATE. MVFR CIGS POSSIBLE AGAIN.

IZZI

&&

.MARINE...
203 PM CST

LIGHT SOUTHEAST TO EAST WINDS WILL INCREASE TO 10-25 KT TOMORROW
MORNING THEN TO 30 KT IN THE AFTERNOON AS THE GRADIENT TIGHTENS
BETWEEN THE DEPARTING HIGH AND THE NEXT LOW. THE LOW MOVES OVER THE
DAKOTAS SUNDAY NIGHT AND MODELS AGREE A BIT MORE IN THE PATTERN
EARLY NEXT WEEK.  HAVE MEDIUM CONFIDENCE IN THE WIND FORECAST WITH
THIS NEXT LOW.  THE LOW WEAKENS AS IT MOVES OVER WISCONSIN TUESDAY
AND A SECOND LOW FORMS OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY
AFTERNOON. THE SECOND LOW WILL RACE NORTH AND DEEPEN REACHING
MICHIGAN WEDNESDAY. MODELS DIFFER ON HOW QUICKLY THE LOW WILL REACH
MICHIGAN.  BOTH MODELS CONTINUE TO FEATURE WESTERLY HIGH END GALES
BEHIND THE LOW WEDNESDAY AFTERNOON INTO THURSDAY.  WEST WINDS
DIMINISH THURSDAY AS THE LOW CONTINUES OFF TO THE NORTH. THE NEXT
LOW MOVES OVER THE SOUTHERN PLAINS THURSDAY AFTERNOON. GUIDANCE
DIFFERS ON THIS LOWS PATH BUT IT SHOULD IMPACT THE LAKE LATE NEXT
WEEK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO





Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1137 PM CST Sat Dec 20 2014

.UPDATE...
ISSUED AT 857 PM CST SAT DEC 20 2014

Clouds cover most of the CWA tonight, but a small area in the east
and southeast is clear at the moment. Expect this area to cloud
over overnight. However, need to make some adjustments to the
cloud cover grids tonight. Remainder of grids look ok. Will send
an update on the forecast, but will not be a change for most of
the area. Changes will be in the east and southeast only.

&&

.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST SAT DEC 20 2014

Cloudy skies persist across much of central Illinois this afternoon:
however, 20z/2pm visible satellite imagery shows a large tear in the
overcast developing from near Decatur southeastward to Flora.
Although the HRRR has been a bit overdone with the clearing, it
continues to suggest at least thinning clouds across the E/SE KILX
CWA late this afternoon into the evening.  In fact, with 925mb winds
remaining light/variable and not really picking up a strong S/SW
component until Sunday, portions of the SE may see partly cloudy
conditions persist through the night.  Further north and west, low
clouds will be on the increase from the west.  Forecast soundings
and model RH profiles indicate that the lowest clouds/fog will
remain just W/NW of central Illinois tonight.  Due to cloud cover
and a light S/SE wind, low temperatures will be a couple of degrees
warmer than last night.  Coolest readings in the middle 20s will
occur south of I-70 where skies will likely remain partly cloudy,
while lows stay in the upper 20s/lower 30s elsewhere.

&&

.LONG TERM...(Sunday through Saturday)
ISSUED AT 259 PM CST SAT DEC 20 2014

Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.

High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.

Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.

The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.

Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1137 PM CST SAT DEC 20 2014

Cloudy skies will continue at all sites next 24hrs. Cigs are
hovering around 3kft with PIA and SPI above 3kft and BMI, DEC, and
CMI below. So will just have 3kft cigs at all sites since PIA and
SPI will likely drop below 3kft sometime overnight. Based on model
soundings and RH fields, am thinking the MVFR cigs will continue
through tomorrow and tomorrow night. Winds will be south-southeast
through the period, with speeds increase to around 10kts tomorrow
afternoon.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten






AREA FORECAST DISCUSSION

NWS TOPEKA KS

 304 AM CST Sun Dec 21 2014

.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014

08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.

For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.

.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014

Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.

Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.

&&

.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1142 PM CST SAT DEC 20 2014

MVFR cigs have moved into MHK and are expected to move into
TOP/FOE in the next few hours. Could see a few breaks but think
these cigs will prevail through the day on Sunday. Did not add
drizzle to terminals as lift is weak and may remain in obs as BR.
Second system approaches right behind first to keep clouds and
possibly light precipitation going into the next overnight period.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...67






AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 437 AM EST SUN DEC 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.

TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.

TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014

COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.

SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.

EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.

THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.

GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1250 AM EST SUN DEC 21 2014

MVFR CEILINGS 1.5-2.5 KFT WILL SLOWLY LOWER TOWARD IFR CIGS LATE
SUNDAY AFTERNOON/EVENING AS S WINDS INCREASE AND BRING MORE MOISTURE
INTO THE AREA. EXPECT LIGHT SNOW TO DEVELOP AT ALL TAF SITES SUN
AFTERNOON WITH THE INCREASE IN MOISTURE IN THE AFTERNOON. VSBYS WILL
INITIALLY BE MVFR WITH THE ONSET OF SNOW BUT COULD LOWER TO IFR
TOWARD EVENING ESPECIALLY AT KCMX AND KSAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014

S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA





AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 1120 PM CST Sat Dec 20 2014

.UPDATE:
Issued at 924 PM CST Sat Dec 20 2014

Clouds are lingering over the entire CWA this evening and will
likely do so into the overnight hours as we are experiencing one
of the longest nights of the year. Latest satellite observations
has shown that low clouds are expanding slowly  eastward over
east central/southeast Illinois while there has been very little
movement over southeast Missouri. Latest ACARS sounding from KSTL
shows a decent inversion between 900-850mb with plenty of moisture
below it, and the RAP keeps plenty of low level moisture over the
CWA tonight, so left cloudy skies over the CWA the rest of the
night. Also raised temperatures tonight, particularly in the
southern and eastern counties where clearing was previously
forecast.

Britt

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 302 PM CST Sat Dec 20 2014

Clouds will persist early tonight and perhaps start to decrease
from south to north by morning. Overnight lows should be similar
to last night in most locations.

Kanofsky

.LONG TERM:  (Sunday through Next Saturday)
Issued at 302 PM CST Sat Dec 20 2014

The primary forecast issues revolve around a large low pressure
system and a deep trough which are expected to affect the area
between Mon and Wed.

The ongoing gradual warming trend (highs today were generally about
5 degrees warmer than yesterday, which in turn was a few degrees
warmer than the previous day) will persist on Sunday and Monday.
Monday`s highs in the mid-40s to lower 50s will be around 10
degrees above average for this time of year.

The aforementioned low pressure system develops over the northern
plains on Sunday and Sunday night, eventually closing off on Mon or
Mon night within a deep trough over the central CONUS. This system
will dominate our weather through Wed, and widespread rain is likely
as it moves into the region on Mon and Mon night. Forecast PW values
of between 0.6" and 0.8" by 00z Tue are above the 75th percentile
and approaching +2 SD for December. A cold front is expected to move
through parts of MO/IL on late Mon night or Tue morning, which is
slower timing than the models were predicting yesterday. By Tue
afternoon or evening, some of the rain will probably switch over
to light snow within the colder post-frontal air mass.
Temperatures return to near or below average behind the front.

Meanwhile, a second vort max is forecast to drop into the central
CONUS trough and induce a new surface wave along the cold front
somewhere in TX/AR/LA (a third, smaller vort max interacts with
the northern upper low center during this time). The resulting
southern system then lifts northeastward on Tue and Tue night, but
there are sufficient differences between the GFS and ECMWF to
preclude getting more specific than SChc/Chc PoPs with a generic
rain/snow mix.

After the trough rotates away on Wed night or Thu, a brief period
of upper ridging is anticipated ahead of the next disturbance. The
12z runs of the ECMWF and GFS are in better agreement on the large
scale pattern compared to 24hrs ago, but the forecast with this
system will still depend on what will have happened with the
previous system, and confidence remains low.

Kanofsky

&&

.AVIATION:  (For the 06z TAFs through 06z Sunday Night)
Issued at 1117 PM CST Sat Dec 20 2014

Focus will continue to be cigs thru the period. Guidance continues
to handle the current trends poorly across the region. Have
therefore continued low confidence in cig heights, but believe
overall trends are reflected in TAFs. Believe conditions will
remain largely as-is except UIN becoming MVFR in the next hour or so.
Cigs shud slowly lift Sun around Noon or during the afternoon.

Specifics for KSTL: Expect cigs to remain in higher MVFR range
thru much of the forecast period with sely to ssely winds aob 10
kts. Believe cigs will lift to VFR Sun afternoon, however, exact
timing remains uncertain.


&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION

NWS GREAT FALLS MT

 1035 PM MST Sat Dec 20 2014

Updated Aviation Discussion

.DISCUSSION...
Update forthcoming. Have lowered temperatures a tad in areas where
advancing clouds have yet to arrive. With clouds overspreading the
area from the west overnight, temperatures will not drop too far.
High wind highlights will remain in place, though wind speeds are
currently below warning criteria along the Rocky Mountain Front.
Latest RUC analysis indicates westerly winds aloft will strengthen
considerably after 10z. Winter Weather Advisory highlights will also
continue. Snow has begun over the Rocky Mountain Front and over
portions of southwest Montana. Snow not expected to begin over the
Central mountains until after midnight, closer to daybreak.

&&

.AVIATION...
UPDATED 0535Z.
A strengthening and increasingly moist West/Northwest flow aloft
will move across the Northern Rockies and MT tonight through Sunday.
This will spread increasing cloudiness across the region tonight
with precipitation and terrain obscurations spreading east over the
mountains tonight and continuing through Sunday. Precipitation will
spread into the KBZN terminal vicinity after 08z with occasional
MVFR in lower CIGS/-SN late tonight through Sunday morning before
conditions improve some Sunday afternoon. Precipitation will be less
widespread at lower elevations of Central/N-Central MT and snow
levels will be around 4000-5000 ft MSL. W-NW winds aloft increase to
around 50kts at ridgetops by Sunday morning with Mtn wave turbulence
likely east of the Rockies and gusty surface winds likely at most
terminals by Sunday afternoon. Hoenisch

&&

.PREV DISCUSSION...Issued 303 PM MST Sat Dec 20 2014

Tonight through Monday...A plume of moisture is pushing through
the Pacific Northwest on a strong westerly jetstream. Ridging
further west will turn the upper level flow northwesterly,
positioning western and southwest Montana beneath the jet exit
region. A shortwave trough will move through this flow from
British Columbia to eastern Montana, causing a lee surface trough
to develop. The overall result is heavy mountain snow, areas of
light rain at low elevations, and strong winds across central
Montana. Little, if any precipitation is expected for western
portion of the central plains. Areas of light freezing rain are
possible tonight generally north and east of the Bears Paw
mountains as warmer air spreads over a colder airmass in northeast
Montana.

Wind gusts will strengthen along the Rocky Mountain Front early
Sunday where a high wind warning remains in effect. Strong wind
gusts will extend further east onto the adjacent plains, but the
high wind watch continues with lowered confidence that winds here
will reach warning criteria. Winter weather advisories now cover
the Rocky Mountains above 5000 feet and for the Central and
Southwest mountains above 5500 feet. Travelers through mountain
passes on Sunday should expect snow covered and icy roads. Snow
will be later to start in the Little Belt and other central
Montana ranges...and will likely continue later into Monday. Nutter

Monday night through Saturday...Shortwave ridge develops over the
region Monday night into Tuesday afternoon with dry conditions at
lower levels but scattered to numerous showers over the mountains.
Temperatures are expected to be generally near or above seasonal
averages. For Christmas Eve and Christmas Day...a Pacific storm
system will affect much of the region. At this time, it appears
that anticipated snow amounts west of a line from Cut Bank to
Lewistown should see 3 to 5 inches of snow over the plains with 6
to 15 inches in the mountains. For areas east of this line...snow
accumulations should range from 1 to 4 inches over the plains with
3 to 8 inches in the mountains. It should be noted that the record
snowfall for Great Falls on Christmas day is only 4.4 inches...and
we might have a chance at that record should a heavier snowband
move through Great Falls. Overall this is not a major storm...but
the timing for precipitation during a major holiday period will
affect travel. Temperatures will also trend colder from Wednesday
through Friday. There is the chance that temperatures on Christmas
Day could be a bit colder than currently forecast because of
clouds/snowfall. After this storm exits the region late
Thursday/early Friday...the weather pattern will become a bit less
active. There will be a small chance for a passing snow shower
over the weekend and into the New Years week...but no significant
snowfall is expected at this time. The main concern tonight is the
GFS13/EC are hinting at some very cold air moving into the region
by Tue Dec 30th...again this is a ways out...and things can change
a bit...but at this time current models are trying to bring down
another batch of arctic air before New Years. Brusda/mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  33  49  31  39 /  20  50  30  30
CTB  26  43  28  36 /  20  40  30  20
HLN  30  47  31  38 /  50  80  40  30
BZN  27  45  27  34 /  70  90  50  30
WEY  30  39  21  31 / 100 100  90  50
DLN  34  46  29  35 /  70  90  60  30
HVR  24  44  27  38 /  20  70  20  20
LWT  31  48  30  37 /  30  80  40  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern
Lewis and Clark...Jefferson...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.

HIGH WIND WATCH from late tonight through Sunday afternoon
Eastern Glacier...Eastern Pondera...Eastern Teton...Liberty...
Toole.

HIGH WIND WARNING until 5 PM MST Sunday Northern Rocky Mountain
Front...Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5500 FEET FOR Beaverhead...
Broadwater...Cascade...Gallatin...Judith Basin...Madison...
Meagher.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls












AREA FORECAST DISCUSSION

NWS HASTINGS NE

 1207 AM CST SUN DEC 21 2014

.UPDATE...
ISSUED AT 630 PM CST SAT DEC 20 2014

DENSE FOG IS ONCE AGAIN BEGINNING TO SETTLE IN OVER OUR EASTERN
FORECAST AREA BASED ON OBSERVATIONS AT GRI...JYR...AND AUH...WHICH
HAVE ALL GONE DOWN TO 1/4 SM IN THE LAST HOUR. FORECAST MODELS
INCLUDING THE RAP...HRRR...AND SREF ARE ALL INDICATING THE
POTENTIAL OF DENSE FOG FROM THE HASTINGS AND GRAND ISLAND AREAS
AND POINTS OFF TO THE NORTH AND EAST FROM THERE. IT IS HARD TO SAY
HOW FAR WEST AND SOUTH THE DENSE FOG WILL DEVELOP...BUT THERE IS
LESS MODEL SUPPORT FOR DENSE FOG AS YOU GET SOUTH AND WEST OF
HASTINGS. IT IS POSSIBLE THAT THE DENSE FOG ADVISORY MAY BE
EXPANDED TO THE SOUTH AND WEST LATER IN THE NIGHT BUT CONFIDENCE
IS NOT THERE TO GO ANY FURTHER SOUTH AND WEST WITH THE ADVISORY AT
THIS POINT IN TIME.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

SATELLITE SHOWS THE AREA OF PERSISTENT STRATUS IN THE EASTERN PART
OF THE FORECAST AREA HAS MOVED LITTLE IN THE PAST COUPLE HOURS BUT
THE THE HIGH CLOUDS MOVING OVER FROM THE WEST THE STRATUS IS
BECOMING MORE DIFFICULT TO SEE. IN THE STRATUS TEMPERATURES CONTINUE
TO STRUGGLE IN THE 30S...BUT AREAS WITH SUNSHINE HAVE WARMED MORE
THIS AFTERNOON.

MAIN CONCERN WITH THIS PERIOD ONCE AGAIN IS THE FOG CHANCES FOR
TONIGHT. A WEAK UPPER LEVEL WAVE MOVES THROUGH THE FORECAST AREA
LATE TONIGHT INTO SUNDAY. WITH THIS EXPECT THERE TO BE SOME HIGHER
CLOUDS THAT MOVE INTO THE AREA...BUT DRY CONDITIONS ARE EXPECTED.
THE LOW LEVEL MOISTURE CONTINUES ACROSS MUCH OF THE AREA THROUGH THE
NIGHT AND INTO SUNDAY. THE STRATUS SEEMS TO BE THE MOST PERSISTENT
IN THE NORTHEAST PART OF THE FORECAST AREA. THE RAP RELATIVE
HUMIDITY AT 925MB HAS BEEN FOLLOWING THE STRATUS THE BEST THIS
AFTERNOON AND THROUGH MOST OF THE NIGHT THE NORTHEAST REMAINS WITH
CLOUDS. IN THE SOUTHEAST THE HIGHER RELATIVE HUMIDITY BUILDS BACK
INTO THE AREA LATE TONIGHT. EXPECT THERE COULD BE SOME FOG NEAR THE
EDGES OF THE STRATUS. WILL KEEP PATCHY FOG ACROSS ALL BUT THE FAR
WEST AND AREAS OF FOG IN THE EAST WHERE THERE IS THE BEST CHANCE FOR
FOG SINCE VISIBILITY AT KJYR STILL HAS LOW VISIBILITY. ONCE AGAIN
THERE IS A POTENTIAL FOR SOME LOWER VISIBILITIES LATE TONIGHT INTO
SUNDAY MORNING AND EXPECT THE EAST IS THE BEST CHANCE.

BY SUNDAY MORNING THE WINDS WILL INCREASE A LITTLE BIT FROM THE
SOUTH. THIS WILL HELP TO MIX THINGS UP A BIT AND THE FOG AND STRATUS
MAY FINALLY MOVE OUT OF THE AREA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

THE BIGGEST CHALLENGE WILL BE DETERMINING PRECIPITATION CHANCES.

WE KICK OFF THE LONG TERM SUNDAY NIGHT WITH A LONGWAVE TROUGH AXIS
OVER THE GREAT PLAINS...AS A STRONG JET HEADS IN ON THE BACKSIDE OF
THE TROUGH..FROM THE PACIFIC NORTHWEST INTO THE GREAT BASIN. MOST OF
THE ENERGY IS ASSOCIATED WITH THE CLOSED LOW IN THE NORTHERN
PLAINS...SO I AM NOT GOING ALL THAT HIGH WITH CHANCES HERE. A
SMALLER SHORTWAVE TROUGH WITHIN THE LONGWAVE TROUGH WILL HELP KICK
SOMETHING UP IN THE EVENING...THE WAY IT LOOKS NOW...BUT SMALL
FEATURES ARE DIFFICULT TO BE VERY EXACT WITH TIMING.  KEEPING THIS
ALL RAIN AS TEMPERATURES DO NOT APPEAR TO BECOME COLD ENOUGH BEFORE
THE PRECIPITATION EXITS WITH THIS PERTURBATION. ANOTHER PERTURBATION
WORKS AROUND THE TROUGH BY MONDAY NIGHT/TUESDAY. TEMPERATURE
PROFILES APPEAR TO SUPPORT SOME LIGHT SNOW MONDAY NIGHT INTO
TUESDAY. PRECIPITATION/SNOW AMOUNTS ARE EXPECTED TO BE LIGHT...WITH
SNOW ACCUMULATION NO MORE THAN AN INCH ANTICIPATED WITH THIS NEXT
PIECE OF ENERGY. AGAIN...CONFIDENCE IS NOT THE HIGHEST WITH
EXACT TIMING.

FLOW IS QUITE PROGRESSIVE AND YET ANOTHER TROUGH MAKES ITS WAY INTO
THE ROCKIES. A PIECE OF ENERGY IS EXPECTED TO BREAK OFF AHEAD OF THE
MAIN WAVE...BUT LOOKS MORE FOCUSED JUST NORTH OF THE CWA. WE COULD
GET SOME SNOW OUT OF THIS...BUT AGAIN...DOES NOT LOOK LIKE WE WILL
GET A LOT OUT OF SNOW. WE SHOULD GET A NOTICEABLE COOL DOWN FRIDAY
BEHIND THE ASSOCIATED COLD FRONT. HIGHS WILL ONLY BE IN THE LOWER TO
MID 30S AND THE WIND COULD BE QUITE GUSTY FROM THE
NORTHWEST...MAKING THE DAY AFTER CHRISTMAS POTENTIALLY BRISK AND
UNCOMFORTABLE.

&&

.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1207 AM CST SUN DEC 21 2014

LIFR CONDITIONS FORECAST AT KGRI TONIGHT INTO SUNDAY MORNING. VFR
CONDITIONS CURRENTLY FORECAST AT KEAR THROUGH THE NEXT 24 HOURS.

A PERSISTENT BAND OF STRATUS IS NOTED OVER EASTERN NEBRASKA THIS
EVENING...WITH THE WESTERN PERIPHERY OF THIS STRATUS SHIELD
EXTENDING FROM NEAR KODX TO NEAR KGRI AND KHSI. FOG...SOME OF
WHICH IS DENSE...ALSO EXISTS WITHIN THIS STRATUS AND COULD IMPACT
KGRI TONIGHT INTO SUNDAY MORNING. GIVEN ALL THIS...WENT AHEAD WITH
LIFR CONDITIONS AT KGRI UNTIL 17Z...WITH MVFR CONDITIONS THEN
EXPECTED AS STRATUS PERSISTS OVER THE AREA DURING THE DAY SUNDAY.
ANOTHER ROUND OF LIFR CONDITIONS ARE FORECAST AT KGRI STARTING 01Z
MONDAY AS GUIDANCE SUGGESTS ANOTHER ROUND OF STRATUS WILL IMPACT
THE AREA. AS FOR KEAR...STRATUS IS CURRENTLY SITUATED TO THE EAST
AND GUIDANCE SUGGESTS THIS WILL NOT CHANGE. GIVEN THIS...WENT
AHEAD WITH VFR CONDITIONS AT KEAR THROUGH THE NEXT 24 HOURS.
OBVIOUSLY THIS WILL NEED TO BE CLOSELY MONITORED TO ENSURE THE
STRATUS DOES NOT MAKE A PUSH TO THE WEST TONIGHT INTO SUNDAY
MORNING. THE SURFACE WIND WILL REMAIN FROM THE SOUTH OR SOUTHWEST
DURING THE TAF PERIOD...STARTING AT AROUND 07KTS TO START THE TAF
PERIOD BUT INCREASING TO NEAR 15KTS DURING THE DAY SUNDAY.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 11 AM CST SUNDAY FOR NEZ039>041-047>049-
     062>064-075>077-087.

KS...NONE.
&&

$$

UPDATE...WESELY
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...BRYANT




AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 332 AM CST SUN DEC 21 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM CST SUN DEC 21 2014

MAIN FORECAST CHALLENGE REVOLVES AROUND UPCOMING PRE CHRISTMAS
SNOW EVENT AND EXPECT SNOW AMOUNTS. CONFIDENCE RISING AS MODELS COMING
INTO BETTER AGREEMENT AND WILL USE MODEL BLEND AND NATIONAL
GUIDANCE FOR ANTICIPATED SNOW AMOUNTS.

AREA OF MAINLY -SN ASSOCIATED WITH CURRENT WAVE AND ZONE OF
ISENTROPIC LIFT WILL CONTINUE TO PROPAGATE EAST AND WILL MONITOR
FOR MORNING POPS. ONCE THIS MOVES THROUGH THIS AM REMAINDER OF THE
DAY SHOULD BE MAINLY DRY WITH PERSISTENT FOG AND LOW CIGS. WITH
SOUTHERLY FLOW...CONTINUED WARM ADVECTION AND WARMER START MOST OF
THE FA WILL BE A FEW DEGREES EITHER SIDE OF 32F.

WAVE WILL DROP INTO DEEPENING TROUGH TONIGHT CLOSING OFF OVER
SD/NE REGION BY MORNING. SURFACE INVERTED TROUGH FROM SD SURFACE
LOW GRADUALLY TAKES SHAPE ACROSS THE CENTRAL DAKOTAS. LOWERING
CONDENSATION PRESSURE DEFICITS AND ISENTROPIC LIFT CONFINED TO THE
SOUTHERN FA SO HAVE HIGHEST POPS THERE TOWARDS MORNING. CLOUDS WILL
HOLD TEMPERATURES UP OVERNIGHT.

STACKED LOW DRIFTS SLOWLY SE MONDAY ALLOWING SFC INVERTED TROUGH
TO SHIFT INTO THE FA. VIA OMEGA FIELDS AND 290K ISENTROPIC SURFACE
LIFT INCREASES DURING THE DAY AND RAISED POPS ACCORDINGLY. HAVE
HIGHEST POPS ASSOCIATED IN ZONE OF 850MB FRONTOGENETIC FORCING
ALTHOUGH AT THIS POINT BANDING SNOW POTENTIAL DOES NOT LOOK GREAT.
ALSO FROM THE 290K SURFACE FULL SATURATION LOOKS SPOTTY. BASED ON
SURFACE TEMPERATURES EXPECT CLOSE TO A 10:1 SNOW RATIO.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 325 AM CST SUN DEC 21 2014

LIFT LOOKS MAXIMIZED MONDAY NIGHT AND SHOULD BE THE FAVORED PERIOD
FOR ACCUMULATING SNOW. FORTUNATELY WIND DOES NOT LOOK TO BE A
SERIOUS ISSUE ALTHOUGH COULD SEE SOME DRIFTING IN OPEN AREAS.

LOW BEGINS TO FILL TUESDAY AND ISENTROPIC LIFT DIMINISHES DURING
THE DAY. STILL EXPECT -SN DURING DURING THE DAY BUT SHOULD
DIMINISH FROM WEST TO EAST DURING THE EVENING. COLD ADVECTION WEAK
AND MIXED LAYER VERY SHALLOW SO WINDS SHOULD BE MANAGEABLE.

CONSIDERING HEADLINES...BASED ON MODEL SOLUTIONS AND NATIONAL
GUIDANCE FEEL THIS WILL BE A FAIRLY EXTENDED PERIOD OF MAINLY
LIGHT SNOW. WITH WIND ALSO NOT APPEARING AS A SERIOUS ISSUE DO NOT
FEEL WATCH WARRANTED AT THIS POINT ALTHOUGH FUTURE ADVISORIES
LOOK LIKELY.

WEDNESDAY-SATURDAY...A BIT OF LIGHT SNOW COULD LINGER EAST OF THE
VALLEY ON WEDNESDAY AS THE LOW CONTINUES TO LIFT AWAY FROM THE AREA.
THEREAFTER HAVE MAINTAINED A PRIMARILY DRY FORECAST. THE 00Z
GFS/ECMWF INDICATE A MORE PROGRESSIVE PACIFIC SHORTWAVE TROUGH
CROSSING THE CENTRAL/NORTHERN PLAINS ON CHRISTMAS...WITH PRECIP
SUPPRESSED MAINLY SOUTH OF THE REGION. THERE WILL ALSO BE A FEW
SHORTWAVE TROUGHS DROPPING SOUTHEASTWARD IN AMPLIFYING NORTHWEST
FLOW ALOFT. WHILE ANY OF THESE MAY PRODUCE SOME LIGHT SNOW...THEY
WOULD BE RATHER MINOR. PERHAPS MORE IMPORTANTLY...THIS PATTERN WILL
ALLOW COLDER AIR TO FILTER SOUTHWARD FOR THE LATTER HALF OF THE
PERIOD. THE GFS/ECMWF BOTH INDICATE 850 MB TEMPS DROPPING TO -20C BY
NEXT SATURDAY...BRINGING TO AN END OUR RECENT STRING OF NEAR TO
ABOVE AVERAGE TEMPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CST SAT DEC 20 2014

WILL KEEP IFR CIGS IN THRU THE TAF PERIOD. CLEARING IN CNTRL ND
JUST ABOUT DVL TO JMS AND HRRR INDICATES IT LIKELY NOT MAKING IT
FURTHER EAST. 925 MB WINDS ARE SOUTHWEST IN THAT AREA NOW AND TURN
MORE SOUTHERLY AGAIN BY 15Z SUN. DVL AIRPORT ONLY SPOT WHERE BRIEF
CLEARING MAY OCCUR...BUT ALSO ALONG THE CLEAR-CLOUD LINE THAT IS
WHERE THE FOG WAS THICKEST FRI NIGHT.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

SHORT TERM...VOELKER
LONG TERM...MAKOWSKI/VOELKER
AVIATION...RIDDLE






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1226 AM CST SUN DEC 21 2014

.UPDATE...
ISSUED AT 1226 AM CST SUN DEC 21 2014

MAIN CONCERN THIS UPDATE IS THE PRECIPITATION NORTH CENTRAL...FROM
BOTTINEAU AND THE TURTLE MOUNTAINS TO RUGBY. FORECAST SOUNDINGS
INDICATE THE PRECIPITATION SHOULD BE IN THE FORM OF FREEZING
RAIN...BUT MAY BE MIXING WITH OR CHANGING TO SNOW. THE AREA OF
PRECIPITATION WAS MOVING EAST AND SHOULD BE OUT OF THIS AREA BY
AROUND 2 AM CST.

THE LOW CLOUDS PERSISTED EAST OF MINOT AND JAMESTOWN AT
MIDNIGHT...BUT HRRR MODEL INDICATES LOW CLOUDS AND FOG RETURNING.
LESS CERTAIN FOR AS FAR SOUTHWEST AS BISMARCK.

UPDATE ISSUED AT 907 PM CST SAT DEC 20 2014

MAIN ISSUE THIS EVENING IS THE FREEZING RAIN AT NORTH CENTRAL. AS
THE PRECIP MOVES EAST INTO COLDER AIR IT IS EXPECTED TO CHANGE
OVER TO SNOW BASED ON MAT TEMP ALOFT FORECAST. WILL RAISE THE
CHANCE TO LIKELY CATEGORY OVER THE NORTH CENTRAL THIS EVENING. SO
FAR WILL HANDLE THIS LIGHT PRECIPITATION WITH SPECIAL WEATHER
STATEMENTS AND SOCIAL MEDIA POSTS.

UPDATE ISSUED AT 644 PM CST SAT DEC 20 2014

SEEING SOME VISIBILITY REDUCTION DUE TO SNOW/MIXED PRECIPITATION AT
TIOGA AND STANLEY WITH A NARROW BAND OF PRECIPITATION. REFINED THIS
AREA IN THE FORECAST ACROSS THE NORTH CENTRAL..AND RAISED POPS T
40 AS IT MOVES TOWARD MINOT. AM CONCERNED ABOUT THE STRATUS ACROSS
THE NORTH CENTRAL AND EAST CENTRAL. HRRR CONTINUES TO SHOW THE
STRATUS FILLING BACK IN ALTHOUGH THE SATELLITE TRENDS SHOW
CONTINUES MOVEMENT EAST OUT OF JAMESTOWN. WILL WATCH FOR THIS
TREND TO CHANGE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)

ISSUED AT 336 PM CST SAT DEC 20 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE LINGERING
PRECIPITATION ASSOCIATED WITH A MID LEVEL WAVE MOVING EAST ACROSS
THE NORTHERN PLAINS TONIGHT...FOG REDEVELOPMENT TONIGHT EASTERN
HALF ALONG TO EAST OF HIGHWAY 83...THEN THE ONSET OF
PRECIPITATION WITH A STRONG STORM SYSTEM ON SUNDAY.

CURRENTLY...MID LEVEL S/WV IMPULSE OVER NORTHWESTERN NORTH DAKOTA
WITH AN ASSOCIATED SFC TROUGH/WARM FRONTAL BOUNDARY DRAPED NORTH
TO SOUTH-SOUTHEAST ACROSS THE CENTRAL DAKOTAS. BAND OF MID LEVEL
CLOUDS AND WEAK RADAR RETURNS ALONG THE BOUNDARY OVER MY EASTERN
COUNTIES AT THE MOMENT...WITH CLEARING SKIES WEST. THE EXCEPTION
IS OVER THE FAR NORTHWEST WHERE WRAP AROUND MOISTURE IS MOVING
INTO...WHERE WE EXPECT INCREASING CLOUDS AND A CHANCE FOR LIGHT
PRECIPITATION EITHER IN THE FORM OF RAIN OR A WINTRY MIX MID TO
LATE AFTERNOON.

WHILE THE BAND OF MID LEVEL CLOUDS IS EATING AWAY AT THE STRATUS
AND FOG CENTRAL INTO EAST...HIGH RES MODELS STRONGLY SUGGEST
REDEVELOPMENT INITIALLY WHERE IT IS AT NOW OVER MY EASTERN
COUNTIES...THEN EXPANDING WEST TO THE HIGHWAY 83 CORRIDOR. WRAP
AROUND PRECIPITATION WILL ALSO WORK ITS WAY EAST TONIGHT ACROSS
THE NORTH BEHIND THE AFOREMENTIONED MID LEVEL WAVE.

NEXT STORM SYSTEM ARRIVES SUNDAY. LEFT EXIT REGION OF A STRONG
UPPER LEVEL JET STREAK WILL PROMOTE LOW PRESSURE DEVELOPMENT OVER
NORTH CENTRAL MONTANA LATE TONIGHT INTO SUNDAY MORNING...WITH
THIS FEATURE THEN MOVING SOUTHEAST INTO EASTERN MONTANA DURING
SUNDAY AFTERNOON. FORCING WILL BE PLENTIFUL WITH INCREASING UPPER
LEVEL DIVERGENCE ON THE NOSE OF THE UPPER JET AND LOW LEVEL
THERMAL UPGLIDE AHEAD OF THE SFC LOW/WARM FRONT. ALREADY PLENTY
OF MOISTURE SO INCREASED POPS TO LIKELY/DEF WEST. THIS EVENT
CONTINUES INTO THE LONG TERM PERIOD SUNDAY NIGHT. SEE BELOW FOR
FURTHER DETAILS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014

RAIN...FREEZING RAIN AND SNOW ARE LIKELY ACROSS THE REGION SUNDAY
INTO MONDAY.

FOR THE SUNDAY INTO MONDAY FORECAST WENT WITH A BLEND OF THE 12
UTC ECMWF/GFS/SREF AS THEY HAVE COME INTO BETTER AGREEMENT AND
DEPICT A REASONABLE SCENARIO. THE 12 UTC NAM APPEARED TO BE TOO
SLOW...TOO MOIST AND BROUGHT THE SURFACE LOW FURTHER NORTHEAST THAN THE
REST OF THE GUIDANCE. HOWEVER...IT IS IMPORTANT TO NOTE THAT THE
18 UTC NAM THAT JUST CAME IN HAS COME INTO BETTER AGREEMENT WITH
THE OTHER GUIDANCE AND NOW HAS THE LOW MOVING A BIT QUICKER AND
TRACKING ACROSS SOUTHWEST NORTH DAKOTA.

...THE MAIN FORECAST CHALLENGE AND UNCERTAINTIES WITH THIS SYSTEM ARE
PRECIP TRANSITION TIMES AND AMOUNTS...

RECENT MODEL TRENDS INDICATE WARMER AIR ALOFT WILL NOT BE AS
PRONOUNCED AND THEREFORE PRECIP TYPES SHOULD BE DETERMINED BY
SURFACE TEMPERATURE ALONE AND LIMITED TO RAIN/FREEZING RAIN/SNOW.
INITIALLY DRY AIR IS EXPECTED TO OCCUPY THE 850-700 MB LAYER. THIS
SHOULD LIMIT INITIAL PRECIP TO A LIGHT DRIZZLE...REGARDLESS OF SURFACE
TEMPERATURES...DUE TO LACK OF ICE (NO SNOW ALOFT). AS MOISTURE
FROM THE WEST MOVES IN AND COLD AIR ADVECTION ALOFT TAKES
HOLD...THE COLUMN SHOULD EVENTUALLY SATURATE AND SNOW WOULD LIKELY
FOLLOW. TEMPERATURES SUNDAY AFTERNOON/EVENING SHOULD BE WARM
ENOUGH ACROSS THE SOUTHWEST TO KEEP ALL PRECIPITATION LIQUID
THROUGH THE EARLY EVENING HOURS. THE INITIAL WAVE OF MOISTURE IS
EXPECTED TO ENTER WESTERN NORTH DAKOTA SHORTLY AFTER SUNSET. COLD
AIR SHOULD TAKE HOLD AFTER MIDNIGHT. IT IS AT THIS TIME WHEN A
TRANSITION TO SNOW IS EXPECTED. LIGHT SNOW IS THEN EXPECTED TO
FALL THROUGH THE DAY MONDAY...EVENTUALLY ACCUMULATING AROUND 3
INCHES ACROSS WESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY.
CENTRAL NORTH DAKOTA MAY EXPERIENCE A LOCAL MINIMUM OF SNOWFALL AS
THE LOW IS PROGGED TO PIVOT ALONG THE RED RIVER (KEEPING MOST OF
THE MOISTURE ALONG AND EAST OF THE JAMES VALLEY THROUGH THE DAY).
IN ADDITION TO SNOW...GUSTY WINDS AROUND 35 MPH MAY CREATE SOME
BLOWING SNOW...REDUCING VISIBILITY. THE STRONGEST WINDS ARE
EXPECTED ACROSS SOUTHWEST AND SOUTH CENTRAL NORTH
DAKOTA...COINCIDENT WITH A 10 MB/6 HOUR PRESSURE RISE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM CST SUN DEC 21 2014

AT MIDNIGHT CST...A WARM FRONT EXTENDED FROM LOW PRESSURE IN
ALBERTA/SASKATCHEWAN SOUTHEAST THROUGH EASTERN NORTH DAKOTA. THE
FRONT WILL BE THE FOCUS FOR A WINTRY MIX OF FREEZING RAIN AND SNOW
FROM BOTTINEAU AND THE TURTLE MOUNTAINS TO THE RUGBY AND HARVEY
AREAS THROUGH 2 AM CST. OTHERWISE AREAS OF FOG WILL AGAIN PLAGUE THE
REGION FROM A MINOT TO BISMARCK LINE. IFR CONDITIONS ARE EXPECTED TO
REDEVELOP EAST OF THIS LINE AND REMAIN VFR WEST. ANOTHER LOW
PRESSURE SYSTEM WILL APPROACH WESTERN NORTH DAKOTA SUNDAY AFTERNOON.
THIS COULD BRING A THREAT FOR FREEZING RAIN/SLEET/SNOW AT KISN AFTER
NOON CST. LEFT VCSH FOR NOW DUE TO UNCERTAINTY...BUT ADDED MENTION
OF -SN AFT 03Z. MORE CERTAIN ABOUT LIGHT RAIN MOVING INTO THE KDIK
AREA AFT 20Z.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JV
SHORT TERM...NH
LONG TERM...AJ
AVIATION...JV






AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 1146 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 1142 PM CST SAT DEC 20 2014

CONTINUED WITH LIKELY POPS SPREADING THRU NW MN NEXT FEW HOURS.
MAIN SNOW AREA NOW ROSEAU TO BAGLEY....JUST ENTERING BEMIDJI.
OTHERWISE MORE CONVECTIVE LOOKING SHOWERS AROUND GRAND FORKS AND
WEST SOUTH OF DVL FROM ACTIVITY THAT WAS EARLIER IN NW ND. THIS
SEEMS TO BE LIGHT SNOW AS WELL. OUTSIDE OF LIGHT SNOW
AREAS...GETTING THE LIGHT FOG/FREEZING DRIZZLE OR MIST. SO KEPT
THAT GOING AS WELL. TEMPS RISING A BIT WITH A GUSTY SOUTH WIND.
KEPT THEM STEADY TONIGHT INTO SUNDAY MORNING.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 310 PM CST SAT DEC 20 2014

FORECAST CHALLENGES WILL BE THE PCPN MOVING THROUGH THE FA TONIGHT
AND THEN THE POTENTIAL FOR A MON/TUE SNOWFALL. AS OF MID AFTERNOON
FOG STILL COVERED THE ENTIRE FA WITH A FEW PATCHES OF DENSE FOG
STILL UP AROUND CANDO/LANGDON. REGIONAL RADAR SHOWED A BAND OF
VERY LIGHT PCPN FROM BOTTINEAU DOWN THRU KJMS MOVING TO THE EAST
AT ABOUT 20KTS. KBIS DID GET A TRACE OF FZDZ AS THIS MOVED THRU
THEM AND NOW K06D IS REPORTING UNKNOWN PCPN. THINK THIS WILL
REMAIN PRETTY LIGHT FZDZ POSSIBLY MIXED WITH SOME LIGHT SNOW AS IT
MOVES THRU TONIGHT. AT THIS POINT THINK IT WILL STAY A THIN BAND
AS IT MOVES EAST THRU ND AND BE PRETTY MINIMAL. THERE IS ALSO SOME
COMMA HEAD PCPN MOVING INTO FAR NW ND NOW ASSOCIATED WITH THE MID
LEVEL WAVE. THEREFORE THERE COULD BE A LITTLE ADDITIONAL PCPN
ALONG THE CANADIAN BORDER LATER ASSOCIATED WITH THIS FEATURE.
MODELS SHOW THE THIN BAND POSSIBLY STRENGTHENING AS IT MOVES INTO
NW MN LATER THIS EVENING WITH A DUSTING TO AN INCH OF SNOW
POSSIBLE THERE. SINCE FOG STILL REMAINS OVER THE ENTIRE FA WILL
MENTION THAT INTO SUNDAY MORNING TOO. NOT SURE ABOUT DENSE FOG AND
WILL LET LATER SHIFTS MONITOR THAT. THERE IS SOME CLEARING OVER
SOUTHWEST ND WITH WEST/SW WINDS BUT DO NOT EXPECT WINDS TO SWITCH
TO THAT DIRECTION TO HELP SCOUR OUT THE FOG/STRATUS HERE. NOT
SURE IF FOG WILL SCOUR OUT ON SUNDAY EITHER SO BUMPED UP SKY
AMOUNTS THEN TOO.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM CST SAT DEC 20 2014

BY 00Z TUE THE SFC LOW SHOULD MOVE INTO THE ND/SD/MN BORDER REGION
SETTING UP A DECENT SNOW BAND OVER EASTERN ND/EXTREME NW MN...IN
AN INVERTED TROUGH. THIS MAINLY STAYS THE SET UP INTO MON NIGHT OR
EARLY TUE BEFORE SHIFTING OFF TO THE EAST. THIS IS USING THE 12Z
ECMWF/NAM WITH THE OTHER MODELS A LITTLE DIFFERENT. LOOKING AT
RAW SNOWFALL FROM THE ECMWF/NAM WOULD BRING UP TO 6 INCHES OVER
EASTERN ND/FAR NW MN. AT THIS TIME WPC SHOWS ABOUT 4-6 INCHES FROM
EAST CENTRAL ND INTO NW MN. STILL SOME UNCERTAINTY...BUT WILL
ISSUE AN SPS TO HIGHLIGHT THE TRANSITION BACK TO SNOWIER WEATHER.

FOR TUESDAY NIGHT THROUGH FRIDAY...MAIN CHALLENGE IS PCPN AMOUNTS
AND WINDS ON BACK SIDE OF DEPARTING LOW PRESSURE OVER THE GREAT
LAKES ON TUESDAY NIGHT INTO WEDNESDAY. MODELS DIFFERING SOMEWHAT IN
PLACEMENT OF PCPN BAND...BUT FOR THE MOST PART PUTTING IT EAST OF
THE RED RIVER. LOOKING FOR PCPN TO BE IN THE FORM OF SNOW AS MAX
TEMPS ALOFT RANGE FROM -4C TO -7C...AND COLDER AIR WILL CONTINUE TO
WRAP BEHIND THE SYSTEM. WINDS SHOULD BEGIN TO DECREASE AS PRESSURE
GRADIENT WEAKENS...AND SFC HIGH PRESSURE TAKES OVER BY CHRISTMAS DAY
BRINGING DRIER CONDITIONS. OTHERWISE...EXPECT COOLING TEMPERATURES
AND A SLIGHT CHANCE FOR PCPN NEAR THE END OF THE PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CST SAT DEC 20 2014

WILL KEEP IFR CIGS IN THRU THE TAF PERIOD. CLEARING IN CNTRL ND
JUST ABOUT DVL TO JMS AND HRRR INDICATES IT LIKELY NOT MAKING IT
FURTHER EAST. 925 MB WINDS ARE SOUTHWEST IN THAT AREA NOW AND TURN
MORE SOUTHERLY AGAIN BY 15Z SUN. DVL AIRPORT ONLY SPOT WHERE BRIEF
CLEARING MAY OCCUR...BUT ALSO ALONG THE CLEAR-CLOUD LINE THAT IS
WHERE THE FOG WAS THICKEST FRI NIGHT.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/HOPKINS
AVIATION...RIDDLE






AREA FORECAST DISCUSSION

NWS TULSA OK

 1127 PM CST SAT DEC 20 2014

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE WILL RESULT IN FURTHER
DETERIORATING CONDITIONS OVERNIGHT WITH ALL AREAS TRANSITIONING TO
IFR/LIFR. GENERALLY OVERCAST CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD THOUGH VISIBILITY SHOULD IMPROVE AFTER 18Z WITH AT
LEAST SOME IMPROVEMENT IN CEILINGS AS WELL...MOST AREAS MVVFR
AFTER 18Z.

&&

.PREV DISCUSSION... /ISSUED 906 PM CST SAT DEC 20 2014/

UPDATE...

PATCHY DRIZZLE WAS ADDED TO THE EVENING FORECAST...SEE DISCUSSION BELOW.

DISCUSSION...

A FEW HOLES IN THE STRATUS DECK DEVELOPED DURING THE DAY...BUT THE
CLOUDS HAVE FILLED BACK IN AT ALMOST ALL LOCATIONS /COPAN WILL
CLOUD UP SOON/ AS OF 03Z. CLOUDS WILL HANG ON THRU THE
NIGHT...CONTINUING A STRING OF CLOUDY DAYS AND NIGHTS THAT
STRETCHES BACK TO THE 17TH. AS SUCH...LOWS WILL NOT BE MUCH
DIFFERENT FROM TODAY`S HIGHS AND THE FORECAST IS WITHIN REASON OF
THE LATEST HRRR GUIDANCE. IN ADDITION...WEAK WARM ADVECTION IN THE
LOW LEVELS IS PROVIDING JUST ENOUGH LIFT FOR PATCHY
DRIZZLE...WHICH SHOWS UP ON RADAR AND IN SOME OF THE METAR OBS.
THEREFORE...HAVE ADDED PATCHY DRIZZLE THRU THE NIGHT TO THE GRIDS. NO
OTHER CHANGES ARE PLANNED TO THE FORECAST THIS EVENING.

LACY

PREV DISCUSSION... /ISSUED 525 PM CST SAT DEC 20 2014/

AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LOW CLOUDS WILL PERSIST THROUGH THE ENTIRE FORECAST
PERIOD. MVFR CONDITIONS EARLY THIS EVENING WILL TRANSITION TO IFR
AS CEILINGS LOWER AND VISIBILITY EVENTUALLY BECOMES REDUCED
OVERNIGHT...SOME AREAS LIKELY TO SEE A PERIOD OF LIFR CEILINGS AS
WELL 12-18Z. MODEST IMPROVEMENT AFTER 18Z SUNDAY.

PREV DISCUSSION... /ISSUED 348 PM CST SAT DEC 20 2014/

DISCUSSION...
ANOTHER CLOUDY DAY FOR TSA CWA. CLOUDS LIKELY ANCHORED
FOR ANOTHER COUPLE OF DAYS BEFORE SUN ARRIVES ON 24TH.
MAX / MIN TEMP ADJUSTMENTS MADE FOR MAINLY CLOUDY SKY.

H500 WAVE  FROM WESTERN CANADA WILL DROP INTO NORTHERN
&  CENTRAL PLAINS OVER THE NEXT COUPLE OF DAYS AS WEST
COAST H500 RIDGE AMPLIFIES. ELONGATED TROUGH - CENTRAL
CANADA TO TEXAS BY TUESDAY.  THIS EVOLUTION WILL BRING
CHANCE PRECIP MONDAY THROUGH TUESDAY.  ECMWF WRF GFS &
DIFFER SOME WITH THIS SYSTEM. OF PARTICULAR CONCERN IS
HOW FAST  COLD AIR WILL ARRIVE IN EASTERN OK NORTHWEST
AR TUESDAY. IF THE COLD AIR ARRIVES EARLY THE TAIL END
OF PRECIPITATION LATE TUESDAY/TUESDAY NIGHT WOULD BE A
WINTRY MIX. GIVEN THAT THE BEST CHANCE FOR PRECIP WILL
BE TUESDAY WITH  HIGH TEMPS IN LOW/MID 40S DID NOT PUT
POSSIBLE WINTRY MIX IN UNTIL TUESDAY NIGHT. AND...THEN
JUST SLIGHT CHANCE EXTREME EASTERN OK AND NORTHWEST AR.

RIDGE MOVES ACROSS THE REGION CHRISTMAS DAY WHILE NEXT
UPPER WAVE DIVES FROM PACIFIC NORTHWEST TO THE ROCKIES.
CHRISTMAS DAY  PROMISES TO OFFER LOTS OF SUN WITH HIGH
TEMPERATURES ABOVE NORMAL IN THE 50 TO 60 DEGREE RANGE.

COLD FRONT WILL SWEEP THROUGH CHRISTMAS NIGHT / FRIDAY
LEAVING BELOW AVERAGE TEMPS NEXT WEEKEND.           GW


&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

$$

SHORT TERM...99
LONG TERM....99
AVIATION...14







AREA FORECAST DISCUSSION...UPDATED

NWS ABERDEEN SD

 1135 PM CST SAT DEC 20 2014

.UPDATE...

SEE UPDATED AVIATION DISCUSSION BELOW.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT

LOW CLOUDS AND FOG WILL ONCE AGAIN BE THE RULE OVERNIGHT AS A VERY
MOIST LOW LEVEL AIR MASS REMAINS IN PLACE. BEEN CLOSELY FOLLOWING
THE HRRR LOW-LEVEL CLOUD COVER PRODUCT WHICH HAS BEEN DOING AN
AMAZING JOB WITH HANDLING STRATUS DECKS THE PAST SEVERAL EVENTS.
IT BASICALLY SHOWS THE STRATUS CLOUDS REMAINING IN PLACE ALL NIGHT
WITH A SLIGHT WESTWARD PUSH ONCE AGAIN ON ITS WESTERN EDGE. WILL
GO WITH PERSISTENCE FORECAST CONCERNING THE FOG AS IT HAS BEEN
OCCURRING THE PAST FEW NIGHTS UNDERNEATH THE STRATUS...SO NO
REASON WHY IT WONT HAPPEN AGAIN...AND IN FACT WIDESPREAD LIGHT FOG
IS ALREADY IN PLACE...WITH LOCALLY THICKER FOG. SEEMS THE MOIST
LAYER IS TOO SHALLOW FOR ANY MEANINGFUL FREEZING DRIZZLE TO OCCUR
OVERNIGHT BUT SOMETHING TO KEEP AN EYE ON ANYWAY.

ON SUNDAY...EXPECTING LOW CLOUDS TO HANG IN TOUGH ACROSS THE EAST
ONCE AGAIN WITH NO REAL SIGNALS FROM ANYTHING TO CLEAR THEM OUT.
WILL ALSO BE WATCHING ARRIVAL OF THE LOW PRESSURE SYSTEM WHICH
WILL ENTER THE DAKOTAS BY SUNDAY EVENING...THEN MOVE INTO WESTERN
MINNESOTA AND IOWA REGION BY MONDAY NIGHT. MODELS STILL HAVING A
TOUGH TIME HANDLING THIS SYSTEM IN REGARDS TO STRENGTH MAINLY.
THEY REALLY DO NOT KNOW HOW TO HANDLE THE EVENTUAL CLOSING OFF AND
SUBSEQUENT MOVEMENT OF THE UPPER LOW...AND ITS ASSOCIATED MOISTURE
AVAILABILITY. THIS WILL BE KEY IN FIGURING OUT JUST HOW MUCH WRAP
AROUND PRECIPITATION WE RECEIVE. BASICALLY TOOK A BLENDED APPROACH
FOR RIGHT NOW WHICH STILL LEAVES THE AREA WITH A COUPLE INCHES OF
SNOW AND SOME MIXED PRECIP IN THE FORM OF FREEZING RAIN AND SLEET
TO START THINGS OFF SUNDAY EVENING. THERMAL PROFILES EVENTUALLY
GET COLD ENOUGH BY MONDAY TO CHANGE THINGS OVER TO SNOW. STILL
HAVE MANY DOUBTS AND LOW CONFIDENCE IN EXACTLY JUST HOW THIS
SYSTEM WILL EVOLVE AND HOW MUCH MOISTURE WILL REALLY BE ASSOCIATED
WITH IT. HAVE A FEELING MODELS MAY NOT LATCH ON TO A MORE
DEFINITIVE SOLUTION UNTIL SOMETIME SUNDAY.


.LONG TERM...TUESDAY THROUGH SATURDAY
LOW PRESSURE WILL BE EAST OF THE REGION WHEN THE PERIOD STARTS
WITH THE POTENTIAL FOR LINGERING SNOW SHOWERS...MAINLY ACROSS THE
EASTERN PART OF THE CWA THROUGH THE DAY TUESDAY. A DECENT PRESSURE
GRADIENT ACROSS THE AREA MAY RESULT IN BREEZY TO WINDY CONDITIONS
AS WELL. WEAK HIGH PRESSURE THEN MOVES IN WITH DRY CONDITIONS
EXPECTED WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM LOOKS TO TRACK
ACROSS THE CENTRAL PLAINS ON THURSDAY...BUT THE MODELS ARE NOT IN
VERY GOOD AGREEMENT WITH STRENGTH OR TIMING. THE GFS AND ECMWF
AGREE SOMEWHAT ON THE TIMING WITH THE GEM BEING MUCH SLOWER.
HOWEVER...THE GFS BRINGS LITTLE IN THE WAY OF
PRECIPITATION...WHILE THE ECMWF PLASTERS MOST OF THE STATE, FOR
NOW...WILL STICK FAIRLY CLOSE TO THE SUPERBLEND KEEPING SCHC/CHC
POPS MAINLY ACROSS THE SOUTHERN CWA THURSDAY INTO THE DAY FRIDAY.
HIGH PRESSURE WILL MOVE BACK IN AFTER THAT WITH DRY CONDITIONS
FRIDAY NIGHT THROUGH THE DAY SATURDAY.

SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE FOR THE FIRST
HALF OF THE PERIOD...WITH HIGHS MAINLY IN THE MID 20S TO LOWER 30S
TUESDAY...WEDNESDAY AND THURSDAY. COOLER AIR THEN MOVES IN BEHIND
THE STORM SYSTEM...WITH HIGHS IN THE TEENS AND 20S FRIDAY AND
SATURDAY.



&&

.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

IFR CIGS WILL REMAIN IN PLACE ACROSS THE EASTERN HALF OF THE CWA
THROUGH THE TAF PERIOD. UNDER THE LOW CLOUDS...VSBYS WILL
GENERALLY BE MVFR IN FOG...BUT THERE WILL LIKELY BE PERIODS OF
IFR VSBYS INTO EARLY SUNDAY MORNING...AFFECTING KABR AND KATY.
VFR CONDITIONS WILL PREVAIL ACROSS THE WESTERN HALF OF THE CWA
BUT KPIR COULD SEE SOME IFR VSBY IN FOG TOWARD MORNING AGAIN.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...WISE

WEATHER.GOV/ABERDEEN






AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 1103 PM CST SAT DEC 20 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014

MUCH OF THE SAME EXPECTED TONIGHT INTO TOMORROW WITH THE LOW
CLOUDS HANGING TOUGH OVER A MAJORITY OF THE AREA. DO NOT REALLY
EXPECT THE CLEARING LINE TO MOVE MUCH THROUGH TOMORROW...WITH ONLY
GREGORY...BRULE AND PORTIONS OF CHARLES MIX COUNTIES SEEING ANY
CLEARING AND SUN. SIGNAL THAT THE DENSER FOG MAY ENCOMPASS MORE OF
THE AREA TONIGHT...MAKING IT TO AROUND THE INTERSTATE 29 CORRIDOR.
SO WILL HAVE TO KEEP AN EYE ON THIS...FOR NOW INCREASED MENTION OF
FOG IN THE GRIDS. GFS AND RAP SUGGEST LOW LEVEL MOISTURE DEPTH WILL
INCREASE TONIGHT AHEAD OF A WEAK UPPER WAVE THAT CROSSES THE REGION.
THIS HAPPENS MAINLY ACROSS PORTIONS OF NORTHWEST IOWA FROM SIOUX
CITY TO SPENCER. SO COULD POTENTIALLY SEE SOME PATCHY DRIZZLE OR
FREEZING DRIZZLE IN THAT AREA...BUT ANYTHING SHOULD BE LIGHT.

GIVEN THE CLOUD COVER...DIURNAL RANGE OF TEMPERATURES WILL BE SMALL.
WILL NOT FALL MUCH TONIGHT...WITH UPPER 20S TO LOW 30S EXPECTED.
THEN ON SUNDAY WE WILL ONLY WARM UP SEVERAL DEGREES...WITH 30S
ACROSS MOST OF THE REGION. WILL START TO BECOME A BIT BREEZY OUT OF
THE SOUTH BY LATER SUNDAY...WITH GUSTS AROUND 25 MPH EAST OF THE
JAMES RIVER.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014

PRECIPITATION LIKELY TO DEVELOP ON SUNDAY...WITH THE BETTER CHANCES
IN THE EASTERN CWA. WHILE THE MAIN WARM FRONT IS TO THE NORTH OF THE
AREA...THE PV ANOMOLY AND COLD FRONT ALOFT SWING THROUGH SUNDAY
NIGHT AND SHOULD ALLOW WHAT WILL BE MAINLY RAIN. THE NORTHERN AND
WESTERN CWA COULD SEE SOME MIXED PRECIPITATION BUT THE CHANCES FOR
PRECIPITATION A LITTLE LOWER IN THESE LOCATIONS SO HOPEFULLY LITTLE
OR NO ACCUMULATION. TEMPERATURES REMAIN PRETTY MILD THROUGH THE
NIGHT AS WELL WITH LOW PRESSURE WRAPPING UP TO THE NORTH AND WEST OF
THE AREA SO MAINLY SOUTHERLY OR WESTERLY FLOW. LOWS GENERALLY FROM
THE LOWER TO MIDDLE 30S.

LOOKS LIKE EVERYONE SHOULD WARM TO AT LEAST THE MID 30S ON MONDAY
WITH LOWER 40S LIKELY IN PARTS OF NORTHWEST IOWA. THE DAYTIME
CHANCES FOR PRECIPITATION SHOULD NOT BE REAL HIGH AND WILL KEEP MOST
LOCATIONS IN THE CHANCE CATEGORY AS THE AREA WAITS FOR THE WRAP
AROUND TO SET UP LATE MONDAY AFTERNOON INTO MONDAY NIGHT. RIGHT NOW
LOOKING LIKE MAINLY A RAIN TO SNOW TRANSITION WITH LITTLE CHANCE FOR
SLEET AND FREEZING RAIN MONDAY AND MONDAY NIGHT.

THE CHANCE FOR SNOW WILL LINGER INTO TUESDAY BUT AMOUNTS WILL REMAIN
FAIRLY MINIMAL. WHEN ALL IS SAID AND DONE LOOKING AT ABOUT A HALF AN
INCH TO AN INCH OVER NORTHWEST IOWA TO 2 TO 3 INCHES FROM HURON TO
MARSHALL. A WAVE TRACKS THROUGH TO THE NORTH OF THE AREA ON TUESDAY
WHICH WILL BRING SOME DRYING ALOFT AND BRING AN END TO THE THREAT
FOR PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY.

THE UPPER LEVEL PATTERN REMAINS FAIRLY ACTIVE THROUGH THE EXTENDED
PERIOD WITH ONE WAVE EXITING ON WEDNESDAY AND ANOTHER MOVING INTO
THE AREA FRIDAY INTO SATURDAY. STILL SOME DECENT DIFFERENCES FOR THE
INCOMING SYSTEM SO NOT OVERLY CONFIDENT ON WHAT TO EXPECT BUT RIGHT
NOW LOOKS COLD ENOUGH FOR ALL SNOW...JUST A MATTER OF WHETHER OR NOT
THIS IS A SYSTEM THAT MOVES THROUGH RATHER QUICKLY OR ONE THAT TAKES
ON JUST A TOUCH OF NEGATIVE TILT LIKE THE ECMWF SUGGESTS AND BRINGS
IN A BETTER CHANCE FOR HEAVIER AMOUNTS. UNFORTUNATELY NO WAY TO
REALLY FIGURE THIS OUT RIGHT NOW SO WILL CONTINUE TO CARRY A CHANCE
OF SNOW THURSDAY NIGHT INTO SATURDAY. FOR NOW WEDNESDAY AND THURSDAY
LOOK MAINLY DRY WITH SLIGHTLY BELOW NORMAL HIGH TEMPERATURES THROUGH
THE PERIOD. OVERNIGHT LOWS WILL LIKELY BE AT OR ABOVE NORMAL DURING
THIS TIME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1103 PM CST SAT DEC 20 2014

POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE PERIOD...WITH
IFR TO LIFR CIGS AND VIS LIKELY. NOT REALLY EXPECTING MUCH CHANGE
FROM THE CURRENT CONDITIONS...SO MAINLY WENT WITH A PERSISTENCE
FORECAST. AREAS OF DENSE FOG AND VLIFR CIGS DEVELOPING THROUGH THE
CENTRAL PORTIONS OF THE FORECAST AREA...PARTICULARLY IN HIGHER
ELEVATIONS EAST OF THE JAMES RIVER VALLEY. STRONGER BOUNDARY LAYER
WINDS DEVELOP BY SUNDAY AFTERNOON...WHICH COULD HELP LIFT CEILINGS
INTO MVFR RANGE FOR A FEW HOURS TOWARD THE END OF THE TAF PERIOD BUT
CONFIDENCE IS LOW SO WILL STICK WITH IFR FOR NOW. COULD SEE SOME
LIGHT RAIN/DRIZZLE DEVELOP TOWARD THE END OF THE PERIOD...BUT TIMING
IS UNCERTAIN SO HAVE ONLY INTRODUCED AT KHON AT THIS TIME.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH





EAST CENTRAL FLORIDA FORECAST DISCUSSION

NWS MELBOURNE FL

 956 AM EST SUN DEC 21 2014

.DISCUSSION...

...MORE HUMID AND WARMER THROUGH WED...
...INCREASED RAIN CHANCES LATE TODAY INTO MON THEN AGAIN LATE TUE
AND WED AHEAD OF NEXT COLD FRONT...

CURRENTLY...
A FEW STORMS SINCE EARLY AM OVER THE EASTERN GULF ARE ASCD WITH
FAVORABLE JET ASCD LIFT AND PRESENCE OF UPR WAVE ENERGY MOVING
ACROSS THE SE STATES. A REVIEW OF AM SOUNDINGS FROM TBW AND XMR SHOW
SUITABLE MOISTURE AND INSTABILITY FOR DEVELOPMENT OF A FEW STORMS
LATER THIS AFTERNOON ROUGHLY ALONG AND NORTH OF THE I-4 CORRIDOR AND
BEACHLINE EXPRESSWAY. THIS MOVES UP THE PERIOD FOR MENTIONING STORMS
ABOUT SIX HOURS FROM EARLIER THINKING. RAPID STEERING AT STORM LEVEL
WL LEAD TO SOME BRIEF MODERATE TO HEAVY RAIN IN AFFECTED AREAS ALONG
WITH WIND GUSTS OF 40 TO 45 MPH AND LIGHTING. DIGITAL AND TEXT PKGS
HAVE BEEN UPDATED FOR ADDITION OF AFTERNOON THUNDER.

(FROM PREV DISC)...STATIONARY FRONT LAYING INSIDE A WEAK INVERTED
TROF EXTENDING FROM THE SW GOMEX ACRS THE NRN FL PENINSULA. EVENING
SOUNDINGS SHOW INCRSG MOISTURE ACRS THE CENTRAL PENINSULA WITH PWAT
VALUES ARND 1.4"...UP FROM 0.8" FROM THE 20/00Z FLIGHT...A FEW
POCKETS OF DRY AIR REMAIN BLO THE H70 LYR THAT INDICATE ADDITIONAL
POTENTIAL FOR MOISTURE LOADING. TO THE S...KMFL HAS MOISTENED TO
1.2" UP FROM 0.9" FROM 20/00Z BUT STILL SHOWS THE REFLECTION OF A
HIGH PRES RIDGE OVER THE FL STRAITS AND THE CENTRAL BAHAMAS WITH
SUBSTANTIAL DRY AIR ABV A SUBSIDENCE INVERSION IN THE H80-H75 LYR.
TO THE N...BOTH KJAX/KTAE ARE NEARLY SATURATED THRU THE H100-H70 LYR
WITH VERY DRY AIR ABV AN INVERSION IN THE H70-H60 LYR. RUC ANALYSIS
INDICATES PLENTIFUL UPSTREAM MOISTURE WITH H100-H70 MEAN RH VALUES
OVER THE GOMEX LARGELY AOA 80PCT...H85-H50 VALUES AOA 50PCT BUT AS
HIGH AS 90PCT WITHIN THE VCNTY OF THE STATIONARY FRONT.

&&

.AVIATION...THRU 22/06Z
THROUGH 15Z-21/18Z...S 5-8KTS WITH VFR CONDS. BTWN
21/18Z-21/22Z...INTERIOR SITES S/SW 4-7KTS WITH MVFR/ISOLD SHRA AND
TS N OF LINE FM KISM-KCOF...COASTAL SITES S/SE 6-9KTS. AFT
21/22Z...S/SE AOB 5KTS.

FM 21/18Z-22/03Z...S OF KCOF-KISM SLGT CHC MVFR SHRAS. AFT
22/03Z...N OF KTIX-KISM PREVAILING MVFR IN NMRS/WDSPRD RA WITH PDS
IFR +RA...S OF KTIX-KISM CHC MVFR SHRAS.

CIGS:
N OF KCOF-KISM: THRU 22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN
FL015-025 IN SCT SHRAS. AFT 22/03Z...MVFR BTWN FL010-020.

S OF KCOF-KLAL: THRU 22/03Z...BTWN FL080-100 WITH PDS MVFR BTWN
FL020-030 IN ISOLD -SHRAS. AFT 22/03Z...BTWN FL060-080 WITH PDS MVFR
BTWN FL015-025 IN SCT -SHRAS.

&&

.MARINE...
DETERIORATING WX CONDS AS A WEAK STATIONARY FRONT JUST N OF THE I-4
CORRIDOR KEEPS THE LCL PGRAD DISRUPTED AND SERVES AS A FOCUS FOR
SHRA AND ISOLD TSRAS. SFC WNDS S-SE BTWN 4-8KTS FROM CAPE CANAVERAL
SWD...VRBL AOB 5KTS N OF THE CAPE IN THE VCNTY OF THE FRONT. SEAS
AOB 2FT...BUILDING TO 2-3FT OVER THE OFFSHORE LEG AFT MIDDAY.

N OF THE CAPE...SCT SHRAS AFT MIDDAY...BCMG NMRS/WDSPRD WITH ISOLD
TSRAS IN AFTN/EVE. S OF THE CAPE...ISOLD/SCT SHRAS AFT
MIDDAY...CONTG THRU THE OVERNIGHT PD.

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.

&&

$$

JP/DKW






AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 1027 AM EST SUN DEC 21 2014

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014

A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.

&&

.NEAR TERM.../REST OF TODAY/...
ISSUED AT 1027 AM EST SUN DEC 21 2014

PATCHES OF LOW CLOUDS LINGER ACROSS THE LOCAL AREA LATE THIS
MORNING...ESPECIALLY OVER THE NORTHWESTERN/NORTHERN ZONES. THESE
CLOUDS HAVE BEEN HOLDING STEADY OR SLOWLY RETREATING OVER THE PAST
COUPLE OF HOURS. SHORT TERM MODELS SUGGEST THE AIR MASS NEAR THE
CLOUD LEVEL WILL BE SLOWLY DRYING OUT TODAY...SO DON/T THINK THE LOW
CLOUDS WILL EXPAND ALL THAT MUCH TODAY.

CURRENT FORECAST HIGHS STILL LOOK GOOD. NO UPDATES PLANNED AT THIS
TIME.

PREVIOUS DISCUSSION FOLLOWS.

SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.

CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.

FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.

TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.

&&

.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014

FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.

CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.

ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.

MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.

CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.

THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014

FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.

LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.

TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.

DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.

CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.

&&

.AVIATION /DISCUSSION FOR 211500Z IND TAF UPDATE/...
ISSUED AT 920 AM EST SUN DEC 21 2014

ONLY INSIGNIFICANT MINOR CHANGE TO VFR CONDITIONS.

PREVIOUS DISCUSSION FOLLOWS...

MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.

MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.

MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...50/JAS
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN/MK

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS













AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 920 AM EST SUN DEC 21 2014

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014

A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.

&&

.NEAR TERM.../TODAY/
ISSUED AT 301 AM EST SUN DEC 21 2014

SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.

CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.

FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.

TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.

&&

.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014

FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.

CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.

ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.

MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.

CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.

THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014

FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.

LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.

TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.

DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.

CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.

&&

.AVIATION /DISCUSSION FOR 211500Z IND TAF UPDATE/...
ISSUED AT 920 AM EST SUN DEC 21 2014

ONLY INSIGNIFICANT MINOR CHANGE TO VFR CONDITIONS.

PREVIOUS DISCUSSION FOLLOWS...

MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.

MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.

MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN/MK

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS











AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 620 AM EST SUN DEC 21 2014

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014

A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.

&&

.NEAR TERM.../TODAY/
ISSUED AT 301 AM EST SUN DEC 21 2014

SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.

CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.

FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.

TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.

&&

.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014

FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.

CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.

ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.

MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.

CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.

THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014

FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.

LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.

TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.

DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.

CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.

&&

.AVIATION /DISCUSSION FOR 211200Z TAF ISSUANCE/...
ISSUED AT 620 AM EST SUN DEC 21 2014

MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.

MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.

MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

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AREA FORECAST DISCUSSION

NWS TOPEKA KS

 510 AM CST Sun Dec 21 2014

...AVIATION UPDATE...

.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014

08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.

For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.

.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014

Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.

Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.

&&

.AVIATION...(For the 12Z TAFs through 12Z Monday Morning)
Issued at 509 AM CST SUN DEC 21 2014

Satellite continues to show MVFR stratus advancing northeast, and
with southerly flow expected to maintain some moisture transport
north think the stratus will hang tough through tonight. Models
continue to show increasing isentropic lift through the afternoon
so drizzle is possible. Confidence in timing is low so opted to
keep VSBY forecast in the MVFR range. However if drizzle develops,
it will likely cause VSBY to be between 1SM and 3SM. Have also
leaned towards keeping CIGS above 1 KFT but there could be some
periods where CIGS drop below 1 KFT. Increasing large scale
forcing late tonight should lead to some -RA moving into the
terminals between 07Z and 09Z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Wolters







AREA FORECAST DISCUSSION

NWS CARIBOU ME

 1009 AM EST SUN DEC 21 2014

.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA THIS AFTERNOON AND
TONIGHT THEN SLOWLY MOVE TO THE EAST MONDAY INTO TUESDAY. A LARGE
AREA OF LOW PRESSURE WILL APPROACH TUESDAY NIGHT THEN TRACK TO OUR
WEST WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...PATCHY FREEZING DRIZZLE HAS ENDED W/MAINLY CLOUDY
CONDITION. CLOUDS WILL HANG ON THE STRONG INVERSION IN PLACE
THROUGH THE AFTERNOON. TEMPS NEEDED ADJUSTMENT TO BRING THEM UP
W/SOME WEAK WAA OCCURRING PER THE LATEST 12Z UA. ADJUSTED THE
AFTERNOON MAXES A FEW DEGREES ACROSS THE BOARD. NORLUN TYPE SETUP
LOOKS TO BE IN ORDER W/LOW WELL S OF THE CWA AND INVERTED TROF
SETTING UP. ADJUSTED THE POPS TO ACCOUNT FOR THIS SETUP FOLLOWING
THE MESOSCALE NAM AND RAP GUIDANCE. THIS FEATURE WILL BE
RESPONSIBLE FOR SOME LIGHT SNOW OR PERHAPS SOME FREEZING DRIZZLE.
WILL BE MONITORING THIS SITUATION THROUGH THE AFTERNOON.

PREVIOUS DISCUSSION...
THE STRONG SUBSIDENCE INVERSION CONTINUES THROUGH THE PERIOD WITH
CLOUDY SKIES AND STEADY TO GRADUALLY MODERATING TEMPERATURES. THE
VERY SHALLOW COLUMN OF MOISTURE WILL TOP OUT NEAR H900 IN NORTHERN
ZONES AND UP TO H850 NEAR THE COAST. INSTABILITY WITHIN THE COLUMN
WILL PRODUCE PATCHY FREEZING DRIZZLE AND FLURRIES ACROSS THE
FORECAST AREA THROUGH TONIGHT. THE ONLY SYNOPTIC SCALE FEATURE
RESOLVED BY NWP WILL BE A WEAK INVERTED TROUGH IN CONCERT WITH AN
UPPER LOW OVER SOUTHERN NEW ENGLAND TODAY. AFFECTS FROM THIS
SYSTEM ARE EXPECTED TO STAY SOUTH OF THE FORECAST AREA...BUT THERE
MAY BE JUST ENOUGH MOISTURE AND LIFT TO GENERATE MEASURABLE
PRECIP IN SOUTHERN HANCOCK COUNTY...MOSTLY IN THE OUTER ISLANDS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA MONDAY. HOWEVER, A STRONG
LOW LEVEL INVERSION WILL LIKELY HOLD THE LOW STRATUS CLOUDS IN PLACE
ACROSS MOST OF THE AREA. THE HIGH WILL GRADUALLY SLIDE EAST INTO THE
MARITIMES MONDAY NIGHT INTO TUESDAY. A BIT OF LOW LEVEL MOISTURE
PUSHING ONSHORE JUST SOUTH AND WEST OF THE HIGH MAY BRING SOME
PATCHY LIGHT SNOW INLAND, AND RAIN ALONG THE COAST, TO SOUTHWESTERN
PARTS OF THE REGION MONDAY NIGHT INTO TUESDAY. OTHERWISE, MOST OF
THE AREA WILL JUST REMAIN OVERCAST THROUGH TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OUR FOCUS GOING INTO THE MIDWEEK PERIOD WILL BE ON A LARGE AND
COMPLEX STORM SYSTEM LIFTING THROUGH THE MIDWEST, WELL TO OUR WEST.
CLOUDS WILL THICKEN TUESDAY NIGHT AND SOME LIGHT RAIN MAY BEGIN TO
SPREAD ACROSS THE AREA BY WEDNESDAY MORNING. BOUNDARY LAYER TEMPS
ARE EXPECTED TO SUPPORT ALL RAIN ACROSS THE AREA, BUT SOME RESIDUAL
LOW LEVEL COLD AIR MAY STILL BE IN PLACE ACROSS SOME NORTHERN SITES
SO WILL MENTION CHC FREEZING RAIN WEDNESDAY MORNING OVER THE NORTH.
RAIN WILL INCREASE IN INTENSITY WEDNESDAY AS THE STORM CENTER LIFTS
THROUGH THE GREAT LAKES. WINDS WILL INCREASE OUT OF THE SOUTHEAST.
MODEL GUIDANCE DIFFERS ON HOW STRONG THE WINDS WILL BE, BUT THE
BEST CHANCE OF HAVING SOME STRONG WINDS WILL BE ALONG DOWNEAST
AREAS, ESPECIALLY NEAR THE COAST, LATE WEDNESDAY INTO WEDNESDAY
NIGHT. RAIN AND WIND WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY
MORNING AS THE LOW LIFTS TO OUR WEST. THE LOW WILL THEN PULL AN
OCCLUDED FRONT ACROSS THE REGION THURSDAY AFTERNOON BRINGING SOME
DRYING. MAINLY DRY WEATHER IS LIKELY FRIDAY AS HIGH PRESSURE
BUILDS SOUTH OF THE AREA. A WEAK FRONTAL BOUNDARY, POSSIBLY
SUPPORTING A SMALL WAVE OF LOW PRESSURE, WILL THEN BRING A CHANCE
FOR SOME LIGHT SNOW NORTH AND SOME SHOWERS DOWNEAST ON SATURDAY.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: EXPECT PREDOMINATELY MVFR CIGS FOR ALL TERMINALS
THROUGH THE PERIOD.

SHORT TERM:
IFR CONDITIONS WILL LIKELY CONTINUE MONDAY INTO TUESDAY AS A DECK OF
LOW STRATUS CLOUDS REMAINS ACROSS THE AREA. IFR CONDITIONS WILL THEN
PERSIST WEDNESDAY INTO EARLY THURSDAY WITH RAIN AND WIND AND
POSSIBLY SOME LOW LEVEL WIND SHEAR IN STRONG SOUTHERLY WINDS.
CONDITIONS MAY IMPROVE LATE THURSDAY FOLLOWING A FRONTAL PASSAGE.

&&

.MARINE...
NEAR TERM: WINDS AND SEAS WILL CONTINUE TO DECREASE UNDER THE
INFLUENCE OF HIGH PRESSURE. NO ADVISORIES ARE ANTICIPATED.

SHORT TERM:
LIGHT EAST TO NORTHEAST WINDS WILL PERSIST MONDAY INTO TUESDAY AS
HIGH PRESSURE SLIDES INTO THE MARITIMES. WINDS AND SEAS WILL
INCREASE OUT OF THE SOUTHEAST WEDNESDAY AS A STRONG STORM LIFTS
NORTHWEST OF THE AREA, LIKELY REQUIRING A GALE OR A STORM WARNING
WEDNESDAY INTO WEDNESDAY NIGHT. GUSTY WINDS WILL BECOME WESTERLY ON
THURSDAY FOLLOWING A FRONTAL PASSAGE.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...HEWITT/MCW
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HEWITT/MCW/BLOOMER
MARINE...HEWITT/MCW/BLOOMER




AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 712 AM EST SUN DEC 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.

TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.

TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014

COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.

SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.

EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.

THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.

GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM EST SUN DEC 21 2014

AS AN INCRSG LLVL S WIND DRAWS MOISTER LLVL AIR INTO THE UPPER LKS
AND AN APRCHG DISTURBANCE CAUSES SN TO DEVELOP OVER THE AREA...
EXPECT CONDITIONS AT CMX AND SAW TO DETERIORATE TO IFR. SAW WL SEE
THE FASTER DETERIORATION AND STRONGER WINDS BECAUSE OF THE UPSLOPE
WIND COMPONENT AT THAT MORE EXPOSED SITE. SINCE THE S WIND PRESENTS
A DOWNSLOPE COMPONENT AT IWD AND EVEN THOUGH SOME IFR CONDITIONS MAY
BE OBSVD THERE FROM TIME TO TIME AFTER THE SN ARRIVES THIS AFTN...
SUSPECT PREDOMINANT CONDITIONS AT THAT LOCATION WL REMAIN MVFR.
AFTER THE EXIT OF THE HEAVIER SN LATE TNGT...CONDITIONS ARE LIKELY
TO IMPROVE TO LO END MVFR AT CMX AND SAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014

S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...JLA






AREA FORECAST DISCUSSION...UPDATED

NWS MORRISTOWN TN

 1022 AM EST SUN DEC 21 2014

.DISCUSSION...
CLOUD COVER CONTINUES TO BE A CHALLENGE TODAY AS THE MODELS HAVE
NOT HANDLED THEM WELL AT ALL...AND HAVE BEEN TOO QUICK TO CLEAR THE
CLOUDS OUT. THE LATEST HRRR CONTINUES TO CLEAR CLOUDS OUT OF ALL
AREAS EXCEPT THE SOUTHERN SECTIONS OF THE AREA THIS AFTERNOON. WILL
IGNORE THE MODELS FOR THE MOST PART AND JUST TRY TO ADJUST SKY
GRIDS TO CURRENT SATELLITE. TEMPS WILL NEED SLIGHT ADJUSTMENTS WITH
THE CLOUDS EXPECTED TO HOLD ON IN THE SOUTH AND FULL SUN LIKELY IN
PARTS OF THE NORTH.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DGS




AREA FORECAST DISCUSSION

NWS AUSTIN/SAN ANTONIO TX

 950 AM CST SUN DEC 21 2014

.UPDATE...
OVERCAST SKIES CONTINUE ACROSS ALL OF SOUTH CENTRAL TEXAS.
OVERRUNNING CONDITIONS WILL CONTINUE TODAY AS SURFACE RIDGE AXIS
ALONG THE COASTAL PLAINS SLOWLY SHIFTS EAST AND RETURN FLOW
DEVELOPS AT THE SURFACE AND MID LEVELS. THIS OVERRUNNING WILL ALLOW FOR
SOME LIGHT PATCHY DRIZZLE THE NEXT HOUR OR SO IN A FEW SPOTS BUT
NOT HEAVY ENOUGH TO MENTION IN THE FORECAST AT THIS TIME. MODELS
SHOW THE OVERRUNNING CLOUDS WILL CONTINUE OVER THE EASTERN HALF OF
THE CWA ALL DAY WHILE THINNER MOISTURE OUT WEST WILL MIX OUT BY
THE AFTERNOON GIVING WAY TO SOME SUNSHINE. LATEST HRRR MODELS
SHOWS THIS AS WELL. MADE SOME MINOR ADJUSTMENTS TO THE GRIDS BUT
OVERALL CURRENT FORECAST TREND IS GOOD.

&&

.PREV DISCUSSION... /ISSUED 535 AM CST SUN DEC 21 2014/

AVIATION.../12Z TAF CYCLE/
MVFR PREVAILS ACROSS CENTRAL TAF SITES WITH STRATUS OVC015 CIGS ON
AVERAGE WITH LOWER IFR CIGS AT KDRT NEAR 600FT AS OF 12Z. EXPECT
KDRT TO IMPROVE THROUGH LATE MORNING/AFT TO VFR. CENTRAL SITES WILL
BE TRICKY WITH MODEL GUIDANCE IN DISAGREEMENT ON WHETHER VFR
CONDITIONS WILL RETURN FEEL STRATUS DECK WILL ERODE IN WEST TEXAS
AND WITH WEAK S/SW FLOW WILL HELP MORE CLEARING TOWARDS KSAT/KSSF
THAN YESTERDAY BUT IT WILL BE CLOSE. FEEL KAUS HAS LEAST CHANCE OF
GOING VFR WITH HIGH END MVFR THROUGH THE AFTERNOON. EXPECT CENTRAL
SITES TO FALL BACK TO LOW MVFR TO POSSIBLY IFR OVERNIGHT. HAVE
FOLLOWED MORE OF NAM/RAP CONSISTENCY FOR KDRT WITH MVFR POSSIBLY
RETURNING OVERNIGHT AS WELL. MUCH QUICKER CLEARING EXPECTED MONDAY
WITH VFR LIKELY FOR ALL SITES BY NOON.

SURFACE WINDS WILL BE S/SW AT 10 KT OR LESS THROUGH THE AFTERNOON
AND OVERNIGHT. /ALLEN/

PREV DISCUSSION... /ISSUED 357 AM CST SUN DEC 21 2014/

SHORT TERM (TODAY THROUGH MONDAY)...
PATCHY FOG HAS DEVELOPED IN SOME SPOTS AND WILL MAINTAIN MENTION
THROUGH MID MORNING. AN UPPER LEVEL TROUGH DEVELOPING OVER THE
CENTRAL STATES GETS AN ENHANCEMENT FROM A COUPLE SHORT-WAVES
MOVING ACROSS TEXAS AND A STRONGER SHORT-WAVE CURRENTLY MOVING
INTO THE PACIFIC NORTHWEST. WEAK ISENTROPIC LIFT MAINTAINS MOSTLY
CLOUDY SKIES AND NEAR AVERAGE TEMPERATURES TODAY. A SOUTHWESTERLY
LOWER LEVEL FLOW DEVELOPS ON MONDAY AS SURFACE LOW STRENGTHENS IN
THE PLAINS LEADING TO WELL ABOVE AVERAGE TEMPERATURES AND WARMEST
OF THE NEXT WEEK AS CLOUDS ERODE.

LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
THE ABOVE MENTIONED PACIFIC NORTHWEST SHORT-WAVE FORCES A STRONG
COLD FRONT SOUTH ACROSS SOUTH CENTRAL TEXAS LATE MONDAY NIGHT INTO
EARLY TUESDAY. THEN THE UPPER LEVEL TROUGH MOVES THROUGH LATER ON
TUESDAY. SOME LIGHT RAIN SHOWERS ARE POSSIBLE ACROSS EASTERN AREAS
WITH THE FRONT TUESDAY MORNING. THERE MAY BE A FEW SPRINKLES WITH
THE UPPER LEVEL TROUGH. HOWEVER...HAVE NOT MENTIONED AS THE LOWER
LEVELS WILL BE DRYING. A STRONG PRESSURE GRADIENT CREATES BREEZY
CONDITIONS WITH GUSTS UP TO 30 MPH TUESDAY. TEMPERATURES FALL BACK
TO BELOW AVERAGE FOR TUESDAY INTO WEDNESDAY. SOME LOW LYING SPOTS
IN THE HILL COUNTRY AND ALONG THE ESCARPMENT WILL DROP TO FREEZING
WEDNESDAY AND CHRISTMAS MORNINGS AS WINDS DECOUPLE SOMEWHAT AS
SURFACE HIGH MOVES ACROSS OUR AREA. THE HIGH MOVES OFF TO THE EAST
WITH SOUTHERLY LOWER FLOW WARMING TEMPERATURES BACK TO ABOVE
AVERAGE FOR CHRISTMAS AFTERNOON. ANOTHER STRONG COLD FRONT MOVES
ACROSS THE AREA FRIDAY LEADING TO BELOW AVERAGE TEMPERATURES FOR
NEXT WEEKEND. NO RAIN EXPECTED WITH THIS FRONT DUE TO LIMITED
MOISTURE. BEYOND THIS FORECAST PERIOD...SOME MODELS ARE SHOWING
EVEN COLDER AIR FOR NEXT WEEK IN THE DAYS BEFORE THE NEW YEAR.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              60  51  71  50  58 /  -   -   -   10  10
AUSTIN BERGSTROM INTL AIRPORT  60  48  71  49  59 /  -   -   -   10  10
NEW BRAUNFELS MUNI AIRPORT     61  50  73  51  60 /  -   -   -   10  10
BURNET MUNI AIRPORT            58  47  72  46  55 /  -   -   -   10  10
DEL RIO INTL AIRPORT           64  45  75  49  60 /  -   -    0  -   10
GEORGETOWN MUNI AIRPORT        59  49  71  48  56 /  -   -   -   10  10
HONDO MUNI AIRPORT             62  48  74  47  61 /  -   -    0  -   -
SAN MARCOS MUNI AIRPORT        61  49  71  50  59 /  -   -   -   10  10
LA GRANGE - FAYETTE REGIONAL   62  51  73  54  58 /  -   10  -   10  20
SAN ANTONIO INTL AIRPORT       61  51  73  50  61 /  -   -    0  10  10
STINSON MUNI AIRPORT           62  50  74  50  61 /  -   -    0  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE/AVIATION...29
SYNOPTIC/GRIDS...09
PUBLIC SERVICE/DATA COLLECTION...33





AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 537 AM CST SUN DEC 21 2014

.AVIATION...
BACK EDGE OF IFR STRATUS RECENTLY EXITED PVW AND WILL DO THE
SAME AT LBB BEFORE 14Z AS DRIER WSW WINDS ARRIVE AND RESTORE
VFR LEVELS. VISBYS ARE ALSO ON THE REBOUND...THOUGH THESE MAY
STILL FALL TO 1SM OR LESS BEFORE 14Z. DURATION AND UNCERTAINTY
OF THIS SCENARIO PRECLUDES A TEMPO MENTION AT THIS TIME.

TIMING THE DRIER AIR AND VFR CONDITIONS INTO CDS STILL YIELDS A
17Z TARGET TIME FROM EARLIER TAFS. UNTIL THEN...MVFR CIGS SHOULD
PREVAIL WITH JUST FEW-SCT CLOUDS AOB 1K FEET.

&&

.PREV DISCUSSION... /ISSUED 434 AM CST SUN DEC 21 2014/

SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.

SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.

LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.

PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.

AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.

JORDAN

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NIL.
&&

$$

93/14/93






AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 434 AM CST SUN DEC 21 2014

.SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.

SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.

&&

.LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.

PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.

AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.

JORDAN

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        59  34  56  25  41 /   0   0   0  50   0
TULIA         58  35  56  28  42 /   0   0   0  50   0
PLAINVIEW     59  36  58  29  42 /   0   0   0  50  10
LEVELLAND     63  37  63  30  44 /   0   0   0  50  10
LUBBOCK       63  38  61  31  44 /   0   0   0  50  10
DENVER CITY   62  39  68  32  46 /   0   0   0  50  10
BROWNFIELD    62  38  67  32  45 /   0   0   0  50  10
CHILDRESS     61  37  59  35  48 /   0   0   0  30  10
SPUR          63  39  63  36  48 /   0   0   0  40  10
ASPERMONT     64  42  67  38  51 /   0   0   0  40  10

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

93/14






AREA FORECAST DISCUSSION

NWS BOISE ID

 927 AM MST SUN DEC 21 2014

.DISCUSSION...RAIN AND SNOW CONTINUE IN IDAHO ZONES NORTH OF THE
SNAKE BASIN THIS MORNING BUT IT HAS DECREASED IN OREGON AND SWRN
IDAHO.  MORE PCPN UPSTREAM WHICH MODELS BRING IN MID-DAY THROUGH
TONIGHT. SNOW CHANGED TO RAIN AT MCCALL AROUND 330 AM MST AND
OUR ENTIRE CWA BELOW 6000 FEET WILL HAVE RAIN RATHER THAN SNOW
THROUGH MID-AFTERNOON.  SNOW LEVEL WILL SLOWLY LOWER THS AFTERNOON
AND TONIGHT AS UPPER WINDS CHANGE FROM WESTERLY TO NWLY.  TEMPS
WILL COOL DOWN WITH HIGHS MONDAY ABOUT 10F LOWER THAN TODAY.  WIND
ADVISORY WILL CONTINUE IN OUR SRN ZONES THROUGH THE DAY.  12Z BOI
RAOB HAD VERY STRONG WESTERLY WINDS ALOFT.  AVALANCHE WARNING
STILL IN EFFECT IN THE SAWTOOTH RECREATION AREA THROUGH AT LEAST
700 AM MONDAY.  GENERAL TREND THROUGHOUT OUR CWA IS COOLER AND
DRIER TONIGHT THROUGH MONDAY.  DRY THROUGH WEDNESDAY THEN COLDER
WITH A CHANCE OF SNOW WEDNESDAY NIGHT.  CHANCE OF LIGHT SNOW C
RISTMAS DAY...THEN DRY AND COLD THROUGH SATURDAY.  NO UPDATES AT
THIS TIME.

&&

.AVIATION...WIDESPREAD MVFR-IFR CONDITIONS WITH PRECIPITATION.
MOUNTAINS OBSCURED. SNOW LEVELS AT THE SURFACE IN CENTRAL IDAHO
MOUNTAINS RANGING UP TO 10K FEET MSL SW OF THE SNAKE RIVER PLAIN.
SNOW LEVELS WILL SLOWLY FALL FROM NORTH TO SOUTH AS PRECIPITATION
BAND MOVES SOUTHWARD TODAY AND TONIGHT. VFR CONDITIONS SOUTH AND
WEST OF A LINE FROM KBNO-KREO IN SE OREGON. SURFACE WINDS WESTERLY
15-25KT WITH GUSTS TO 45KT THIS AFTERNOON IN SE OREGON AND EASTERN
MAGIC VALLEY EAST OF KJER...NORTHWESTERLY SURFACE WINDS UP TO 15KT
ELSEWHERE. WINDS ALOFT AROUND 10K FT MSL...NW 50-75KT DIMINISHING TO
NW 35-50KT BY 12Z MON.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH MONDAY...THE WARM FRONT IS FINALLY
SHOWING SIGNS OF PUNCHING NORTHWARD AS THE MODELS HAVE PROMISED.
BOGUS BASIN IS ABOVE FREEZING AND THE WEB CAM INDICATES RAIN. KMYL
IS STILL SNOWING...BUT SHOULD CHANGE TO RAIN SHORTLY. THE WSW WILL
BE ALLOWED TO EXPIRE AT 3 AM WITH THE MORNING FORECAST PACKAGE.
LIGHT TO MODERATE RAIN IS STILL FALLING OVER MOST OF THE REGION...
AND WE EXPECT IT TO CONTINUE FOR MUCH OF TODAY AS A WARM MOIST
FLOW REMAINS ENTRENCHED ALOFT. LATEST HRRR MODEL INDICATES A BREAK
THIS MORNING IN THE LOWER TREASURE VALLEY AND WESTERN PORTIONS OF
THE UPPER TREASURE VALLEY...INCLUDING BOISE. BUT THEN PRECIP
SPREADS BACK INTO THESE AREAS THIS AFTERNOON. THIS WILL HAVE A
STRONG IMPACT ON TEMPERATURES TODAY. WE HAVE LOWERED THE FORECAST
FOR THESE AREAS DUE TO HIGH-RESOLUTION MODEL DATA INDICATING
LESS WARMING THAN PREVIOUSLY EXPECTED TODAY. AS WE MOVE INTO
TONIGHT...SNOW LEVELS MOVE BACK DOWN AND MOISTURE WILL FINALLY
BEGIN TO DECREASE. THE CHANCE OF PRECIP DECREASES SHARPLY MONDAY
AND TEMPS WILL COOL FURTHER. WINDS WILL BE STRONG TODAY IN SE
OREGON...THE SOUTHWEST HIGHLANDS OF IDAHO...AND THE HIGHER TERRAIN
OF SRN TWIN FALLS COUNTY. THE WIND ADVISORY IS STILL ON TRACK TO GO
INTO EFFECT AT 8 AM MST AND RUN UNTIL 5 PM MST.

LONG TERM...MONDAY NIGHT THROUGH SATURDAY...CONDITIONS ARE
EXPECTED TO CONTINUE TO DRY OUT MONDAY NIGHT AND TUESDAY AS A
RIDGE OFF OF THE CALIFORNIA COAST AMPLIFIES. THIS WILL KEEP
TEMPERATURES ABOVE NORMAL. MODELS ARE IN GOOD AGREEMENT OF THE
RIDGE STARTING TO FLATTEN OUT ON WEDNESDAY AHEAD OF A TROUGH
MOVING IN FROM COASTAL BRITISH COLUMBIA. THE LATEST GFS AND ECMWF
RUNS HAVE BEGUN TO AGREE ON TIMING OF THIS TROUGH AND ASSOCIATED
COLD FRONT. PRECIP CHANCES WILL SPREAD FROM NW TO SE LATE WED
NIGHT WITH SNOW LEVELS AROUND 5000 FT DROPPING TO 2000 FT BY
EARLY CHRISTMAS MORNING. HOWEVER...THIS SYSTEM WILL LIKELY MOVE
OUT OF THE AREA QUITE QUICKLY SO CONDITIONS SHOULD DRY OUT ONCE
AGAIN CHRISTMAS AFTERNOON/EVENING. THE ASSOCIATED COLD FRONT WILL
BRING TEMPERATURES BACK TO NEAR NORMAL FOR THE REST OF THE PERIOD.
A COOLER NORTHWEST FLOW WILL SET IN FOR FRIDAY AND BEYOND.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON IDZ015-029-030.
     AVALANCHE WARNING IN THE SAWTOOTH RECREATION AREA UNTIL 730 AM
        MST MONDAY.
OR...WIND ADVISORY UNTIL 5 PM MST /4 PM PST/ THIS AFTERNOON ORZ061-063.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...LC
AVIATION.....KA
PREV SHORT TERM...SP
PREV LONG TERM....EP



AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 408 PM CST SUN DEC 21 2014

.SHORT TERM...
246 PM CST

THROUGH TUESDAY...

TONIGHT THROUGH TUESDAY...
BROAD SFC RIDGE HAS BECOME CENTERED OVER THE NORTHEAST CONUS...AND
CONTINUES TO SLOWLY DRIFT EAST/NORTHEAST. THE GRADIENT ACROSS THE
GREAT LAKES HAS REMAINED LIGHT THIS AFTN...WITH A MAINLY SOUTHERLY
FLOW. CLOUDS REMAIN LOCKED IN ACROSS THE FORECAST AREA...WITH SOME
CLEARING JUST SOUTHEAST OF THE CWFA IN CENTRAL/NORTHERN IN. SFC
TEMPS HAVE BEEN ABLE TO WARM TO THE MID/UPR 30S...WITH DEW PTS
HOVERING AROUND 30-33 DEG. MOST THE EVENING WILL REMAIN DRY...WITH
THE WEAK MID-LVL WAVE SLIDING NORTHEAST ACROSS IOWA/WISC WITH SOME
LGT SNOW...OTHERWISE MOST OF THE FORECAST AREA SHUD REMAIN DRY THRU
THE OVERNIGHT PERIOD.

500MB VORT BEGINS TO LIFT NORTHEAST FROM THE CENTRAL PLAINS BEFORE
DAYBREAK MON...PUSHING THE MOIST CHANNEL FURTHER EAST ACROSS THE
FORECAST AREA. WITH SOUNDINGS SUGGESTING A WARM WEDGE DEVELOPING
ALOFT...P-TYPE COULD BE A CHALLENGE ARND DAYBREAK. GUIDANCE WOULD
SUGGEST TEMPS COULD BE WARM ENOUGH TO LIMIT PRECIP TO LGT
RAIN...WITH NEAR SFC TEMPS HOLDING ARND THE FREEZING MARK...SO HAVE
CONTINUED THE MENTION OF FZRA MAINLY SOUTH OF ROCKFORD. CLOSER TO
ROCKFORD THE THERMAL PROFILE IS A LITTLE MORE TRICKY AND COULD ALLOW
SOME LGT SNOW/SLEET AT THE ONSET CHANGING TO LGT RA/FZRA BEFORE
MIDDAY. THROUGHOUT THE AFTN TEMPS WILL STEADILY WARM...NEARING 40
DEG IN MOST LOCATIONS AS WARM/MOIST AIR CONTINUES TO ADVECT NORTH
ACROSS THE CWFA. MOST GUIDANCE INDICATES LGT RAIN WILL PERSIST THRU
THE AFTN/EVE HOURS...WITH THE DRY WEDGE NOT ARRIVING UNTIL CLOSER TO
DAYBREAK TUE. LOCAL SOLUTION SUGGESTS SLIGHTLY EARLIER WITH BRINGING
A TEMPORARY END TO THE PRECIP...JUST AFT MIDNIGHT MON NGT.

TEMPS OVERNIGHT WILL REMAIN MILD IN THE UPR 30S/NEAR 40. WITH THE
TROUGH TAKING ON A NEGATIVE TILT MIDDAY TUE...THE SFC LOW WILL BE
WRAPPED UP ACROSS CENTRAL WISC. GUIDANCE HAS BOUNCED AROUND POSSIBLY
KEEPING EITHER DRY/LOW CHC POPS OVER NORTHERN IL/NORTHWEST IN
TUE/TUE AFTN...BUT HAVE OPTED TO HOLD ONTO A SLT CHC OF RAIN. WITH
WARM AIR CONTINUING TO ADVECT NORTH...SFC TEMPS COULD PUSH INTO THE
MID/UPR 40S WITH A FEW LOCATIONS IN THE SOUTHEAST REACHING 50 DEG.
BY TUE EVENING THE TROUGH AXIS IS PROGGED TO EJECT ANOTHER SFC LOW
ACROSS THE GULF STATES...THEN QUICKLY LIFT NORTH ACROSS THE TENN
VALLEY LATE TUE NGT. MOISTURE WILL FILL BACK IN ACROSS THE FORECAST
AREA TUE NGT...WITH RAIN BECOMING MIXED WITH SNOW OVERNIGHT. TEMPS
WILL SLOWLY COOL...SO THE PERIOD OF RAIN/SNOW MIX COULD LINGER
AWHILE.

BEACHLER

&&

.LONG TERM...
246 PM CST

WEDNESDAY THROUGH SUNDAY...

MID-WEEK ENSEMBLES CONTINUE TO PROG A SLIGHT STRENGTHENING TO THE
DOWNSTREAM RIDGE OVER THE CANADIAN MARITIME...WHICH WILL LIMIT HOW
FAR EAST THE SECONDARY LOW WILL PROGRESS. OPERATIONAL SOLUTIONS
CONTINUE TO LIFT THE STRENGTHENING LOW NORTH ACROSS THE OHIO VALLEY
WED AFTN...AND QUICKLY NORTH OF LAKE HURON BY LATE WED NGT. WRAP
AROUND MOISTURE AND COOLER AIR WILL BRING SOME LGT SNOW TO NORTHERN
IL WED.

FOR CHRISTMAS DAY THE DOWNSTREAM RIDGE WILL BEGIN TO
WEAKEN...ALLOWING THE MID-LVL TROUGH TO BECOME PROGRESSIVE AND PUSH
EAST. THIS SHUD BRING AN END TO THE LGT SNOW/FLURRIES BY DAYBREAK.
TEMPS SHUD RETURN TO THE MID/UPR 30S...ALONG WITH PERHAPS SOME
BREAKS IN THE CLOUD COVER BY THE AFTN. MID-LVL HEIGHTS SHUD START TO
INCREASE THUR NGT/FRI...HOWEVER THIS LOOKS TO BE SHORT-LIVED AS YET
ANOTHER TROUGH IS PROGGED TO DIG SOUTH FROM THE CANADIAN ROCKIES
INTO THE NORTHERN PLAINS. THE STRONGER PUSH OF COLDER AIR LOOKS TO
ARRIVE SAT...ALTHOUGH THIS MAY ONLY BE A SHORT DURATION WITH THE
SEMI-ZONAL PATTERN SETTING UP FOR THE SECOND HALF OF THE WEEKEND.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* CIGS LOWER TO MVFR AND IFR MONDAY
* RAIN DEVELOPS MIDDAY MONDAY

IZZI

//DISCUSSION...UPDATED 18Z...

LOW PRESSURE IS IN PLACE OVER THE NORTHERN ROCKIES THIS AFTERNOON
AND WILL MOVE ACROSS THE MID MISSOURI VALLEY OVERNIGHT WITH A WARM
FRONT LIFTING ACROSS ILLINOIS THROUGH THE DAY MONDAY. SOUTH WINDS
THIS AFTERNOON WILL TURN MORE SOUTHEASTERLY TONIGHT IN ADVANCE OF
THE FRONTAL BOUNDARY. MODELS HAVE LITTLE CONSISTENCY WITH RESPECT TO
CIG HEIGHTS...SO FOR NOW WILL MAINTAIN PREVIOUSLY ADVERTISED TRENDS
WITH SOME MODELS SHOWING SOME RECOVERY IN CIG HEIGHTS EARLY MONDAY.
HAVE MORE CONFIDENCE IN CIGS LOWERING AGAIN THROUGH THE AFTERNOON
MONDAY WITH IFR SEEMING LIKELY AS THE WARM FRONT LIFTS ACROSS THE
TERMINALS. PRECIP WILL OVERSPREAD THE REGION BY LATE MORNING OR
EARLY AFTERNOON. SOUNDINGS SHOW THE COLUMN COOL ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY BUT SHOULD FAIRLY QUICKLY WARM ENOUGH
TO BECOME ALL RAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* LOW-MEDIUM CONFIDENCE IN CIGS TONIGHT AND MONDAY
  MORNING...MEDIUM CONFIDENCE IN CIGS MONDAY AFTERNOON
* HIGH CONFIDENCE IN WINDS
* MEDIUM-HIGH CONFIDENCE IN PRECIP TIMING.

IZZI

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...RAIN. MVFR/IFR LIKELY. S-SE WINDS.

TUESDAY...CHANCE OF RAIN AND MVFR/IFR ESPECIALLY EARLY. S-SW WINDS.

WEDNESDAY...CHANCE OF SNOW...POSSIBLY MIXED WITH RAIN EARLY.
MVFR/IFR LIKELY. NW WINDS BECOMING W.

THURSDAY...DRY. MVFR CIGS POSSIBLE EARLY. W WINDS BECOMING SW.

FRIDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE. S WINDS BECOMING W.

SATURDAY...DRY. MAINLY VFR. W WINDS.

RATZER

&&

.MARINE...
204 PM CST

SMALL CRAFT ADVISORY...KEPT THE CURRENT SMALL CRAFT AS IS AND
EXPANDED IT TWO ZONES SOUTH THROUGH CALUMET HARBOR.  WAVES WILL
BECOME HAZARDOUS OVERNIGHT NORTH OF WILMETTE HARBOR AND THEN WINDS
AND WAVES WILL BECOME HAZARDOUS TOMORROW AFTERNOON. MARGINAL SMALL
CRAFT CONDITIONS ARE POSSIBLE ALONG THE INDIANA NEARSHORE WATERS AND
DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE A SMALL CRAFT ADVISORY AT
THIS TIME.

HIGH PRESSURE IS OVER THE EAST COAST WHILE THE NEXT LOW IS OVER THE
NORTHERN PLAINS.  SOUTH WINDS HAVE INCREASED TO 15-25 KT ACROSS THE
LAKE AND WILL CONTINUE TO INCREASE TO 30 KT THIS AFTERNOON. WINDS
BECOME SOUTHEAST TOMORROW AS THE LOW MOVES OVER THE EASTERN PLAINS
AND WEAKENS.  THE LOW THEN WEAKENS OVER WISCONSIN TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. WINDS WEAKEN ACROSS THE LAKE MONDAY NIGHT AND
BECOME WEST TO NORTHWEST 10-15 KT TUESDAY NIGHT.  A SECOND LOW FORMS
OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY NIGHT AND QUICKLY
DEEPENS AS IT MOVES NORTH.  GUIDANCE DIFFERS ON HOW FAR TO OUR EAST
THE LOW WILL PASS...BUT THINKING IT WILL BE OVER THE EASTERN GREAT
LAKES. GUIDANCE HAS ALSO BACKED OFF ON WIND SPEEDS BEHIND THE LOW
AND WILL ONLY CARRY OCCASIONAL GALES IN THE GLF AT THIS TIME. SO
HAVE WEST TO NORTHWEST WINDS INCREASING TO 30 KT WEDNESDAY NIGHT.
THE BEST WINDOW FOR GALES WOULD BE LATE WEDNESDAY NIGHT.  THE LOW
THEN CONTINUES NORTHEAST INTO QUEBEC THURSDAY AND HAVE SOUTHWEST
WINDS DECREASING THURSDAY.  ANOTHER LOW SLIDES ACROSS THE PLAINS
THURSDAY AFTERNOON AND WILL IMPACT THE LAKE FRIDAY.  GUIDANCE
DIFFERS ON HOW STRONG THE LOW WILL BE WHEN IT MOVES OVER THE
LAKE...SO HAVE LOW CONFIDENCE IN THE FORECAST LATE NEXT WEEK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.

     SMALL CRAFT ADVISORY...LMZ741-LMZ742...NOON MONDAY TO 3 AM
     TUESDAY.

&&

$$

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  [top]

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
257 PM CST Sun Dec 21 2014

.SHORT TERM...(Tonight)
ISSUED AT 256 PM CST SUN DEC 21 2014

Low pressure currently over southern Alberta will track into eastern
South Dakota by 12z Mon.  Ahead of the system, a tightening pressure
gradient will produce southeasterly winds of 10 to 15 mph across
central Illinois tonight.  Due to these sustained winds and a partly
to mostly cloudy sky, overnight low temperatures will be a few
degrees warmer than last night and several degrees warmer than
either the MAV or MET guidance.  Lows will once again be coolest
across the SE KILX CWA where skies will initially be mostly clear
and warmest across the W/NW where clouds will hold firm.  Readings
will range from the upper 20s near the Indiana border to the middle
30s along/west of I-55.  Any precipitation associated with the
approaching system will remain west of the Mississippi River until
later Monday morning, as forecast soundings remain dry through 12z.


&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 256 PM CST SUN DEC 21 2014

Beginning to look like a good news/bad news scenario setting up with
the storm system expected to impact central and southeast Illinois
from Monday into Christmas Eve. If recent model trends hold, the
good news will be that significant weather related travel impacts
are not expected on Christmas Eve in the area. The bad news, for
some, would be that a "White Christmas" is looking less likely
locally.

We are still looking at active weather the next few days as a
complex, slow moving, storm system impacts the area. A 160+ kt
upper-level jet crashing into the Pacific NW & northern Rockies will
continue to amplify troffing over the middle of the nation, a trof
that will be with us for a few days.

A closed upper low is expected to develop over the northern
Plains/upper Midwest Monday, nearly vertically stacked with an
associated surface low. The WAA/isentropic lift ahead of these lows
will be accompanied by a periods of rainfall from Monday into Monday
night. Then, another vigorous piece of upper energy will round the
base of the mean trof Tuesday into Wednesday, accompanied by the
development of another surface low. This second low will become the
dominant low, with the first low expected to dissipate. A dry slot
is progged to wrap around the initial upper low, no doubt aided by
the secondary wave intercepting much of the deeper moisture. This
dry slot may result in much of Tuesday/Tuesday night ending up dry
across the northwest 1/2 of the forecast area, certainly drier than
it looked yesterday. The southeast 1/2 of the forecast area should
see rain chances persisting Tuesday and Tuesday night, as this area
will be closer to the track of the secondary wave. The remaining
precipitation will change over to light snow on Christmas Eve, but
model agreement is strengthening and this suggests that snowfall
will not be a significant impact across the forecast area.

Mostly dry conditions are expected by Christmas Day as the system
heads northeast into Canada. Another, much weaker, system is progged
to impact the area by Friday. However, guidance suggests that this
system will have minimal moisture to work with until it moves east
of the forecast area. This is because there will not have been much
time for the atmosphere to recover from the cold/dry advection in
the wake of the midweek system. So, only have a slight chance of
rain and/or snow for Friday into Friday night. While temperatures
will be above normal for much of this week, they will trend below
normal behind Friday`s system.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1149 AM CST SUN DEC 21 2014

MVFR ceilings prevail at the KILX terminals late this morning:
however, the cloud cover is beginning to erode across east-central
Illinois. 1730z visible satellite imagery shows clearing line from
KPRG to just north of K1H2 and lifting slowly northward. Based on
timing tools and latest HRRR forecast, skies will partially clear
at KCMI between 20z and 21z. Further west, forecast soundings
suggest a continued MVFR overcast through the afternoon before
ceilings gradually improve to VFR this evening in advance of an
approaching storm system. IFR ceilings will develop/spread across
the area between 13z and 16z Mon as rain showers arrive from the
southwest. Winds will be from the S/SE at 10-5kt through the
entire period.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Barnes







AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 140 PM CST SUN DEC 21 2014

.SHORT TERM...
620 AM CST

THE MAIN CONCERNS DURING THIS PERIOD WILL MAINLY BE FOCUSED ON
THE TIMING OF RAINFALL EXPECTED MONDAY AND MONDAY NIGHT.

WARM AIR ADVECTION/ISENTROPIC ASCENT HAS PRODUCED SOME DRIZZLE AND
EVEN SOME OCCASIONAL LIGHT SNOW/FLURRIES ACROSS PORTIONS OF NORTH
CENTRAL ILLINOIS EARLY THIS MORNING. TEMPERATURES ACROSS THE AREA
CONTINUE TO HOLD STEADY EITHER RIGHT AT FREEZING OR A DEGREE OR TWO
BELOW IN SOME AREAS. THEREFORE...THERE WILL CONTINUE TO BE THREAT
FOR SOME MINOR GLAZING ON UNTREATED SURFACES ACROSS PORTIONS OF
NORTH CENTRAL ILLINOIS THROUGH AROUND DAYBREAK.
THEREAFTER...TEMPERATURES SHOULD WARM ABOVE FREEZING...ESSENTIALLY
ENDING THIS THREAT. ASIDE FROM SOME LINGERING PATCHY DRIZZLE THIS
MORNING MOST AREAS WILL BE CLOUDY AGAIN...BUT DRY AS TEMPERATURES
WARM INTO THE UPPER 30S THIS AFTERNOON.

MODEL GUIDANCE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT THROUGH
TUESDAY...WITH AN INITIAL AREA OF LOW PRESSURE TRACKING EASTWARD
FROM THE NORTHERN HIGH PLAINS LATER TODAY...TO THE UPPER MISSISSIPPI
VALLEY BY TUESDAY. THIS STILL WOULD KEEP ALL OF NORTHERN
ILLINOIS/NORTHWESTERN INDIANA IN THE WARM SECTOR THROUGH TUESDAY. IT
THIS SYSTEM LOOKS TO BE A DECENT RAINFALL PRODUCER FOR MUCH OF THE
AREA...WITH THE BEST TIMING BEING MONDAY AFTERNOON THROUGH LATE
MONDAY NIGHT/EARLY TUESDAY MORNING. SEVERAL UPPER LEVEL SHORT WAVE
DISTURBANCES ROTATING THROUGH THE LARGER SCALE UPPER LOW OVER THE
PLAINS...SHOULD RESULT IN WHAT APPEARS TO BE TWO ROUNDS OF
RAINFALL...WITH THE FIRST AROUND THE MONDAY AFTERNOON
TIMEFRAME...AND THE SECOND MONDAY NIGHT. THERE IS A SMALL CHANCE
THAT AS THE PRECIPITATION ONSETS LATE MONDAY MORNING...THAT IT COULD
START AS A MIX OF SLEET AND LIGHT SNOW...GIVEN THE INITIAL COOL
ATMOSPHERIC PROFILE. HOWEVER...WARM AIR ADVECTION WILL QUICKLY WARM
THINGS ENOUGH TO RESULT IN ALL RAIN AREA-WIDE BY EARLY MONDAY
AFTERNOON.

DURING THE DAY ON TUESDAY IT APPEARS THAT WE MAY EXPERIENCE A MID
LEVEL DRY PUNCH...WHICH IF DOES OCCUR WOULD RESULT IN LOW CLOUDS
AND PERHAPS SOME LINGERING DRIZZLE AND LOWER CHANCES OF MUCH
ADDITIONAL RAIN. GIVEN THIS...I HAVE LOWERED POPS A BIT DURING THE DAY
ON TUESDAY. TEMPERATURES ACROSS THE AREA MONDAY NIGHT AND TUESDAY
AS WE REMAIN IN THE WARM SECTOR LOOK TO BE MILD FOR THIS TIME OF
YEAR...WITH 40S EXPECTED.

&&

.LONG TERM...
620 AM CST

TUESDAY NIGHT THROUGH SATURDAY...

FORECAST MODEL SOLUTIONS CONCERNING THE EVOLUTION OF THE SURFACE AND
UPPER LEVEL PATTERN ACROSS THE CENTRAL CONUS FROM TUESDAY NIGHT
THROUGH CHRISTMAS HAVE BECOME MORE DIVERGENT OVER THE PAST COUPLE
RUNS...WITH SEVERAL SOLUTIONS EVEN NOW INDICATING THE POSSIBILITY
OF A MUCH WEAKER SURFACE SYSTEM OVER THE GREAT LAKES INTO
CHRISTMAS EVE DUE TO THE FAILURE OF THE UPPER LEVEL TROUGH
BECOMING NEGATIVELY TILTED OVER THE MISSISSIPPI VALLEY...AS MANY
MODELS HAD BEEN PREVIOUSLY ADVERTISING. HOWEVER...GIVEN THIS
SYSTEM IS STILL 3.5 TO 4 DAYS AWAY...I AM HESITANT TO MAKE ANY
MAJOR CHANGES TO THE GOING FORECAST FOR THIS PERIOD...AS IT
APPEARS THE LATEST DETERMINISTIC MODEL SOLUTIONS ARE REALLY JUST
SHOWING US THE INHERENT HIGH AMOUNT OF CHAOS IN THE SYSTEM WITH
SUCH A RAPIDLY CHANGING PATTERN. AS SUCH...I REALLY HAVE NO
CONFIDENCE IN ANY OF THE LATEST 00 UTC DETERMINISTIC GUIDANCE AND
WOULD PREFER TO SEE ADDITIONAL RUNS OVER THE NEXT DAY OR TWO SHOW
SIMILAR TRENDS BEFORE BEGINNING TO MAKING ANY BIG CHANGES. MY
HUNCH IS WE WILL CONTINUE TO SEE ADJUSTMENTS IN THE DETERMINISTIC
RUNS OVER THE NEXT COUPLE OF DAYS AS THE MODELS ATTEMPT TO RESOLVE
THE EVOLUTION OF THE UPPER LEVEL PATTERN OVER THE CENTRAL CONUS.

FOLLOWING THIS SYSTEM...MODEL GUIDANCE IS INDICATING ANOTHER
DISTURBANCE DIGGING ACROSS THE PLAINS STATE BY THURSDAY...AND THIS
COULD RESULT IN ANOTHER PERIOD OF PRECIPITATION ACROSS PORTIONS OF
THE AREA BY FRIDAY. HOWEVER...UNCERTAINTY WITH THIS STORM IS
EXTREMELY HIGH...GIVEN THAT THE ACTUAL EVOLUTION OF THE FIRST STORM
SYSTEM WILL NEED TO BE IRONED OUT FIRST.

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* PERIODS OF MVFR CIGS THROUGH TONIGHT...THEN INCREASING CHANCES
  FOR CIGS LOWERING TO IFR THROUGH THE AFTERNOON MONDAY.
* PRIMARILY RAIN OVERSPREADING TERMINALS MONDAY AFTERNOON...THOUGH
  A WINTRY MIX IS POSSIBLE NEAR THE ONSET.

BMD

//DISCUSSION...UPDATED 18Z...

LOW PRESSURE IS IN PLACE OVER THE NORTHERN ROCKIES THIS AFTERNOON
AND WILL MOVE ACROSS THE MID MISSOURI VALLEY OVERNIGHT WITH A WARM
FRONT LIFTING ACROSS ILLINOIS THROUGH THE DAY MONDAY. SOUTH WINDS
THIS AFTERNOON WILL TURN MORE SOUTHEASTERLY TONIGHT IN ADVANCE OF
THE FRONTAL BOUNDARY. MODELS HAVE LITTLE CONSISTENCY WITH RESPECT TO
CIG HEIGHTS...SO FOR NOW WILL MAINTAIN PREVIOUSLY ADVERTISED TRENDS
WITH SOME MODELS SHOWING SOME RECOVERY IN CIG HEIGHTS EARLY MONDAY.
HAVE MORE CONFIDENCE IN CIGS LOWERING AGAIN THROUGH THE AFTERNOON
MONDAY WITH IFR SEEMING LIKELY AS THE WARM FRONT LIFTS ACROSS THE
TERMINALS. PRECIP WILL OVERSPREAD THE REGION BY LATE MORNING OR
EARLY AFTERNOON. SOUNDINGS SHOW THE COLUMN COOL ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY BUT SHOULD FAIRLY QUICKLY WARM ENOUGH
TO BECOME ALL RAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* LOW CONFIDENCE IN CIGS REST OF TODAY AND TONIGHT...MEDIUM
  CONFIDENCE IN CIGS LOWERING TO IFR MONDAY AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM IN SPEEDS.
* MEDIUM CONFIDENCE IN PRECIP TIMING. LOW-MEDIUM IN PRECIP TYPE
  INITIALLY BUT HIGH CONFIDENCE IN EVENTUALLY BECOMING ALL RAIN.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...RAIN. MVFR/IFR LIKELY. S-SE WINDS.

TUESDAY...CHANCE OF RAIN AND MVFR/IFR ESPECIALLY EARLY. S-SW WINDS.

WEDNESDAY...CHANCE OF SNOW...POSSIBLY MIXED WITH RAIN EARLY.
MVFR/IFR LIKELY. NW WINDS BECOMING W.

THURSDAY...DRY. MVFR CIGS POSSIBLE EARLY. W WINDS BECOMING SW.

FRIDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE. S WINDS BECOMING W.

SATURDAY...DRY. MAINLY VFR. W WINDS.

RATZER

&&

.MARINE...
240 AM CST

MAIN MARINE CONCERNS CONTINUE TO FOCUS ON STRENGTHENING
SOUTH-SOUTHEAST WINDS TODAY THROUGH LATE MONDAY...AND POTENTIAL FOR
GUSTY NORTHWEST-WEST WINDS...POSSIBLY GALES...FROM LATE WEDNESDAY
INTO THURSDAY.

SURFACE HIGH PRESSURE RIDGE MOVED EAST OF THE LAKE ON SATURDAY
ALLOWING WINDS TO BECOME SOUTHERLY. THE SURFACE PRESSURE GRADIENT
WILL SLOWLY TIGHTEN ACROSS THE UPPER MIDWEST AND WESTERN LAKES TODAY
AS AN AREA OF LOW PRESSURE MOVES SOUTHEAST FROM THE LEE OF THE
CANADIAN ROCKIES...WITH SOUTH-SOUTHEAST WINDS INCREASING INTO THE
25-30 KT RANGE FROM LATER THIS AFTERNOON INTO MONDAY AS THE LOW
APPROACHES FROM THE NORTHERN PLAINS. THE IS EXPECTED TO OCCLUDE AND
BEING TO FILL LATE MONDAY NIGHT...ALLOWING THE GRADIENT TO WEAKEN
AND WINDS TO DIMINISH EARLY TUESDAY. THE REMNANT SURFACE TROUGH WILL
CROSS THE LAKE LATE TUESDAY NIGHT OR EARLY WEDNESDAY...WITH LIGHT
WINDS SHIFTING TO THE WEST-NORTHWEST.

FORECAST MODEL SOLUTIONS FOR THE SURFACE PATTERN FROM WEDNESDAY
AFTERNOON THROUGH THURSDAY HAVE BECOME MORE DIVERGENT OVER THE PAST
FEW RUNS...WITH QUITE A SPREAD IN THE LOCATION TRACK AND DEPTH OF A
SECOND SURFACE LOW WHICH IS EXPECTED TO DEVELOP SOMEWHERE ACROSS THE
OHIO OR TENNESSEE RIVER VALLEYS. OVERALL...GUIDANCE INDICATING A
WEAKER LOW DURING THIS PERIOD...THOUGH MODELS ARE OBVIOUSLY
STRUGGLING WITH DEVELOPMENT OF DIGGING SOUTHERN STREAM JET STREAK
AND THE RESULTING UPPER TROUGH AND DOWNSTREAM SURFACE LOW
DEVELOPMENT. WITH SUCH DIVERGENT SOLUTIONS HAVE AVOIDED MAKING LARGE
SWINGS IN THE FORECAST...AND HAVE HELD ON TO THE GENERAL SCENARIO OF
PREVIOUS FORECAST...THOUGH WITH SLIGHTLY WEAKER WIND FIELD DURING
THE LATE WEDNESDAY-THURSDAY PERIOD. ADJUSTMENTS WILL UNDOUBTEDLY BE
REQUIRED AS SUITE OF MODELS DEVELOP BETTER CONVERGENCE/AGREEMENT IN
THEIR SOLUTIONS.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.

&&

$$

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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1149 AM CST Sun Dec 21 2014

.UPDATE...
ISSUED AT 1035 AM CST SUN DEC 21 2014

16z/10am visible satellite imagery shows cloud cover blanketing
much of central Illinois: however, skies remain mostly clear along
and south of the I-70 corridor into the Ohio River Valley.
Short-wave ridging in advance of an upper-level disturbance over
the Central Plains will allow heights to slowly rise today.
This along with continued backed southeasterly low-level flow will
cause the leading edge of the cloud cover to erode
north/northwestward this afternoon. Am already beginning to see
evidence of this on satellite this morning, so have updated sky
grids accordingly. End result will be mostly sunny skies
along/south of I-70, with skies becoming partly sunny as far
northwest as a Shelbyville to Champaign line. Further west, mostly
cloudy conditions will prevail across the remainder of the area.
High temperatures will be a few degrees warmer than yesterday,
with readings reaching the upper 30s and lower 40s.

&&

.SHORT TERM...(Today)
ISSUED AT 537 AM CST SUN DEC 21 2014

All but extreme southeast Illinois was cloudy early this morning and
the latest satellite trends suggest the southeast may see the clouds
move in for a brief time over the next couple of hours. With the
clear sky, a few locations in southeast Illinois have seen some
patchy fog develop, but with the clouds starting to move in we don`t
expect the fog to become widespread. Further to the northwest, some
patchy drizzle has been occurring over parts of extreme eastern Iowa
and some of that, at least based on radar, was tracking into areas
mainly along and west of the Illinois River, so will carry some
patchy drizzle wording for early this morning before that shifts to
our north. Surface temperatures have risen into the middle 30s early
this morning along with dew points now into the lower 30s, so am not
expecting any problems from freezing drizzle at this point.

The slow moving high pressure system that had given parts of our
area some sunshine the past couple of days was finally drifting off
to our east allowing a southerly flow to develop over most of the
forecast area. Forecast soundings indicate our southeast counties
may see the lower cloud cover drift north-northeast out of their
area this morning allowing some sun for a time today. Further north
and west, short range models not as optimistic with a mostly cloudy
sky prevailing. We should see the temperatures continue to moderate
from the highs of yesterday with most areas close to or above the 40
degree mark this afternoon.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 537 AM CST SUN DEC 21 2014

Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.

High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.

Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.

The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.

Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1149 AM CST SUN DEC 21 2014

MVFR ceilings prevail at the KILX terminals late this morning:
however, the cloud cover is beginning to erode across east-central
Illinois. 1730z visible satellite imagery shows clearing line from
KPRG to just north of K1H2 and lifting slowly northward. Based on
timing tools and latest HRRR forecast, skies will partially clear
at KCMI between 20z and 21z. Further west, forecast soundings
suggest a continued MVFR overcast through the afternoon before
ceilings gradually improve to VFR this evening in advance of an
approaching storm system. IFR ceilings will develop/spread across
the area between 13z and 16z Mon as rain showers arrive from the
southwest. Winds will be from the S/SE at 10-5kt through the
entire period.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...07
AVIATION...Barnes







AREA FORECAST DISCUSSION

NWS TOPEKA KS

 1147 AM CST Sun Dec 21 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014

08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.

For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.

.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014

Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.

Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1125 AM CST SUN DEC 21 2014

The main challenges for the TAF period will continue to be the
CIG/VIS categories. IFR is expected to persist during the first
half of the period. Winds will be fairly steady but there is
potential for some gusts into the mid 20 mph range as we see some
directional changes come into play. Some uncertainty remains with
light areas of drizzle along with potential for light rain. But
for now, just keeping mention of drizzle. Lower confidence with
the actual CIG/VIS remains with these areas as well, but generally
improving conditions can be expected near the end of the TAF period.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Drake






AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 1233 PM EST SUN DEC 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.

TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.

TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014

COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.

SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.

EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.

THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.

GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1233 PM EST SUN DEC 21 2014

AN APPROACHING UPPER LEVEL DISTURBACE FROM THE WEST WILL ALLOW LIGHT
SNOW TO DEVELOP ACROSS UPPER MICHIGAN LATE THIS AFTERNOON AND EARLY
EVENING. CIGS AT CMX AND SAW WILL LOWER INTO THE IFR RANGE DURING
THIS TIME. DOWNSLOPING SOUTHERLY WINDS AT IWD SHOULD KEEP CIGS THERE
ON THE FENCE BETWEEN MVFR AND IFR. LIGHT SNOW WILL TAPER OFF
OVERNIGHT TONIGHT BUT ENOUGH LOW LEVEL MOISTURE WILL KEEP CIGS AT
CMX AND SAW AT THE MVFR/IFR THRESHOLD THROUGH MONDAY MORNING.

&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014

S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...JLA
AVIATION...MZ
MARINE...JLA










AREA FORECAST DISCUSSION

NWS BILLINGS MT

 350 PM MST SUN DEC 21 2014

.SHORT TERM...VALID FOR MON AND TUE...

DYNAMIC SHORTWAVE IN NW FLOW ALOFT CURRENTLY PUSHING THROUGH
SOUTHEAST MT. STRONG WINDS HAVE BEEN OCCURRING FOR SEVERAL HOURS
IN HARLOWTON AND JUST RECENTLY WE HAVE SEEN GUSTS TO 58-59 MPH
SURFACE AT BILLINGS AND COLUMBUS...WITH SOME ASSISTANCE FROM THE
LIGHT SHOWER ACTIVITY AROUND THE AREA. PEAK GUSTS COINCIDE PRETTY
WELL WITH RAP 800MB WINDS...AND AS TEMPS HAVE REACHED THE LOW 50S
THE BOUNDARY LAYER IS WELL-MIXED. RAP/GFS SHOW 800MB FLOW
INCREASING TO 55 KTS OVER THE NEXT FEW HOURS FROM BILLINGS TO
SHERIDAN...IN PATH OF VORT MAX AS SEEN ON WATER VAPOR IMAGERY.
GIVEN THE INGREDIENTS AND AN EXPECTATION OF A FEW HOURS OF STRONG
W-NW WINDS HAVE ISSUED A HIGH WIND WARNING THRU MIDNIGHT TO
INCLUDE COLUMBUS...BILLINGS...HARDIN...LODGE GRASS AND SHERIDAN.
ELSEWHERE WILL MAKE NO CHANGES TO WIND HIGHLIGHTS THOUGH WOULD
EXPECT A DECREASE LATER TONIGHT IN THESE AREAS AS WELL.
LIVINGSTON...BIG TIMBER AND NYE HAVE STAYED BELOW ADVISORY
CRITERIA FOR MUCH OF THE DAY BUT WITH STRONGER GUSTS NEARBY WILL
LET THE HIGHLIGHT RIDE A BIT LONGER.

HEAVIEST SNOW HAS ENDED OVER OUR SW MTNS AS MOISTURE PLUME HAS
BEEN PUSHED W-S OF OUR AREA...BUT UNSTABLE NW FLOW IS CONTINUING
TO PRODUCE SNOW SHOWERS WHICH ARE PROBABLY LOCALLY HEAVY. IN
ADDITION...THERE IS A SHORT-LIVED BULGE OF ISENTROPIC ASCENT
LATER TONIGHT INTO MONDAY MORNING AHEAD OF ANOTHER PIECE OF
ENERGY...AND THIS SHOULD ENHANCE THE SNOW SHOWERS ESPECIALLY FOR
NW ASPECTS. WILL LET THE WINTER STORM WARNING RIDE FOR THE
BEARTOOTH ABSAROKAS THRU NOON TOMORROW.

NEXT AREA OF CONCERN IS OUR FAR EAST AS TROWAL WRAPS SOUTHWARD
ACROSS FAR SOUTHEAST MT TOMORROW ON BACK SIDE OF UPPER LOW IN THE
DAKOTAS. LOOKS LIKE A 1-3 INCH SNOWFALL WHICH COMBINED WITH NW
WIND GUSTS OF 35-45 MPH WILL CAUSE SOME BLOWING SNOW AND POOR
TRAVEL CONDITIONS. HAVE ISSUED A WINTER WX ADVISORY TO COVER THIS
FOR FALLON AND CARTER COUNTIES. IMPACTS WILL ALSO BE FELT FURTHER
WEST TOWARD MILES CITY...BROADUS...LAME DEER AND SHERIDAN THOUGH
CURRENT INDICATIONS ARE THAT GREATEST SNOW ACCUMS WILL BE CLOSER
TO THE DAKOTAS BORDER. WIND GUSTS SHOULD EXCEED 50 MPH IN SHERIDAN
TOMORROW...WITH ENHANCEMENT ALONG THE EAST SLOPES OF THE BIGHORN
MOUNTAINS. PCPN IN OUR EAST SHOULD TAPER OFF BY EARLY TUESDAY AS
HEIGHTS BEGIN TO RISE FROM THE WEST.

PERIOD OF DRY WEATHER IS IN STORE TUESDAY AND TUESDAY NIGHT AS
RIDGE BUILDS IN FROM THE WEST. BACKED FLOW ALOFT ALONG WITH LEE
SIDE TROFFING AND COLD AIR IN THE PARK WILL BRING OUR NEXT PERIOD
OF STRONG SW WINDS FOR THE USUAL GAP AREAS.

TEMPS WILL TAKE A STEP DOWN THE NEXT TWO DAYS BUT WILL REMAIN A
LITTLE ABOVE NORMAL WITH HIGHS MOSTLY IN THE 30S TO LOWER 40S.
COOLEST TEMPS WILL BE FELT NEAR THE DAKOTAS BORDER.

JKL

.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...

CONSISTENCY IN THE MODELS IS NOT OPTIMAL BUT STILL STRONG ENOUGH
TO START SUPPORTING A DEPICTION OF HOW THE WEATHER WILL UNFOLD
THROUGH THE CHRISTMAS HOLIDAY. WEDNESDAY WILL BE VERY WINDY ACROSS
A LARGE PORTION OF THE REGION AND MILD. WEDNESDAY NIGHT A COLD
FRONT MOVES INTO AFTER THE EVENING HOURS...SOMETIMES BETWEEN 10 PM
AND 4 AM. THIS BRINGS A SHIFT TO MUCH COLDER TEMPERATURES AND
SNOWFALL. THIS SOLUTION IS SUPPORTED BY A BLEND OF LATEST WRF AND
ECMWF AND GFS IS THE OUTLIER. FRONT IS FAST MOVING WITH SHORT
LIVED SNOWFALL CHANCES BUT UPPER LEVEL SUPPORT MOVES OVER THE
FRONTAL ZONE WHICH COULD ALLOW FOR A 2 TO 3 INCH SNOWFALL IN 8
HOURS.

HAVE DRIED OUT WEDNESDAY DAY FORECAST A LITTLE BUT KEPT SNOWFALL
CHANCES FOR WEDNESDAY NIGHT AND CHRISTMAS DAY. FRIDAY IS A QUIETER
DAY WITH COOL NORTHWEST FLOW BUT IT IS MOSTLY DRIER WITH A CHANCE
OF MOUNTAIN SNOW. SATURDAY LOOKS RELATIVELY QUIET TOO BUT AN
ADDITIONAL ROUND OF GAP FLOW WINDS COULD BE SETTING UP LATER ON
SATURDAY NIGHT.

MODELS PICKING UP ON A STRONGER ARCTIC INTRUSION NEXT WEEKEND BUT
NOT CONFIDENT IF ITS SUNDAY OR MONDAY. THIS LOOKS LIKE A MUCH
STRONGER PATTERN CHANGE THAN THE WEDNESDAY NIGHT SYSTEM. BORSUM

&&

.AVIATION...

VERY WINDY CONDITIONS SHOULD BE EXPECTED THIS EVENING FOR A KBIL
TO KSHR LINE AND AREAS WEST WITH WIND GUSTS TO 50KT POSSIBLE WITH
SUSTAINED WINDS OF 35 KT. WINDS WILL DECREASE AFTER MIDNIGHT BUT
REMAIN STRONG ESPECIALLY ALONG THE FOOTHILLS. WINDS WILL AGAIN
INCREASE IN STRENGTH AFTER DAYBREAK ON MONDAY.

MOUNTAIN AREAS WILL CONTINUE TO SEE PERIODS OF HEAVY SNOW SHOWERS
WITH SIGNIFICANT OBSCURATIONS. OTHERWISE LOWER ELEVATIONS CAN
EXPECT BRIEF MVFR CONDITIONS WITH THE HEAVIER SHOWERS THIS
EVENING. BORSUM.

&&

.PRELIMINARY POINT TEMP/POPS...

    MON     TUE     WED     THU     FRI     SAT     SUN
-----------------------------------------------------------
BIL 034/041 025/039 026/041 029/034 015/030 014/031 015/029
    22/W    20/N    02/W    66/S    31/B    11/B    22/S
LVM 031/037 016/034 023/041 028/036 012/029 012/032 018/032
    44/J    20/N    03/W    77/S    41/B    12/S    22/S
HDN 031/040 022/037 019/040 025/033 011/029 010/030 010/028
    33/J    30/B    02/W    66/S    31/B    11/B    22/S
MLS 029/034 022/035 020/040 025/031 013/027 014/029 009/026
    47/J    31/B    13/W    43/S    21/E    12/S    22/S
4BQ 031/034 024/034 017/042 026/035 013/028 012/030 010/028
    47/J    62/J    11/E    45/S    21/E    11/B    22/S
BHK 027/030 021/030 015/039 022/030 010/023 012/025 007/022
    78/J    62/J    12/W    33/S    21/B    12/S    22/S
SHR 030/037 022/035 018/042 025/033 012/030 011/034 013/030
    44/W    41/B    02/W    66/S    31/B    11/B    22/S

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WARNING IN EFFECT UNTIL NOON MST MONDAY FOR ZONES
      28-42-63.
     WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 5
      AM MST TUESDAY FOR ZONES 33-37.
     HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MST TONIGHT FOR
      ZONES 34-35-38-57.
     WIND ADVISORY IN EFFECT UNTIL NOON MST MONDAY FOR ZONES
      41-65-66.
     WINTER STORM WARNING IN EFFECT UNTIL NOON MST MONDAY FOR ZONE
      67.
WY...HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MST TONIGHT FOR
      ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS




AREA FORECAST DISCUSSION

NWS GREAT FALLS MT

 1055 AM MST Sun Dec 21 2014

...UPDATE TO AVIATION...

.UPDATE...

MDOT highway cams reveal snow falling over area mountain passes
with reduced visibility as forecast. This snow will continue
through the day. Light freezing rain has been reported in Ft.
Belknap southeast of Havre. Light rain showers over this area
continue to move east with temperatures rising above freezing, so
expect this hazard to end by 11am. Wind gusts along the Rocky
Mountain Front are just now exceeding 60mph. Surface pressure is
beginning to rise along a line from Cut Bank to Great Falls to
Helena. Expect wind gusts to increase with these pressure rises
along the Rocky Mountain Front, then expand eastward into Central
Montana through the afternoon. HRRR guidance for wind gusts
supports strengthening wind gusts today. High wind warnings and
winter weather advisories for mountain snowfall remain in effect.
Updated temperatures and winds forecast for today to align closer
with observed trends. Nutter

&&

.AVIATION...
UPDATED 1755Z.
A strong and unsettled northwesterly flow aloft is propelling a
surface cold front through central Montana at this hour. Isolated to
scattered rain and freezing rain showers ahead of the front will
move into eastern Montana by 20Z. Behind the front, gusty winds and
isolated showers will continue over the plains and in the valleys
through 00Z Monday. However, the western and southwest mountains
will continue to see widespread snow, blowing snow and obscurations
through the period. Strong winds aloft will continue to fuel
mountain wave turbulence to the lee of north-south oriented mountain
ranges as well as low level wind shear. Eastern slopes of the
Rockies can anticipate local wind gusts in excess of 70 mph at times
through this afternoon. mpj

&&

.PREV DISCUSSION...
/ISSUED 438 AM MST Sun Dec 21 2014/

Today through Tuesday...Strong west to northwest flow aloft today. A
shortwave will move through this flow and keep winds very strong.
Radar shows light precip over the western mountains. This
precipitation will spread east this morning as a low pressure
shortwave and associated cold front cross the Rockies. A surface low
pressure trof is over the CWA with higher pressure over Western. The
NAM gives 40 kt winds at just above the boundary level through the
day. Due to the position of the jet and timing of the front, will
cancel the current high wind watch but issue a warning for Lewis and
Clark, Cascade, Chouteau, Judith Basin, and Fergus counties. The
period of strongest winds will be associated with the frontal
passage. Will start Lewis and Clark warning with the issuance of
this forecast package, and start the others at 18z. The jet over the
Rockies will gradually shift to a more northwest direction during
the night. A ridge will build over the Eastern Pacific and northwest
flow aloft will be over the zones Monday. This ridge will be over
the Pacific Northwest by early Tuesday morning and move over the
zones during the day. The airmass will remain dry underneath the
high pressure but also remain rather cool. Zelzer

Tuesday night through Sunday...Expect another Pacific storm system
to move through the region from Tuesday night through Christmas Day.
Precipitation will be light to start with Tuesday night into
Wednesday morning...but will pick up in intensity by late Wednesday
afternoon through Christmas morning. It still looks like the swath
of heaviest snowfall will fall west of a line from Cut Bank to
Lewistown...with the Havre area only seeing around an inch of snow.
Otherwise...overall total snow accumulations still look to be on
track from previous forecasts...with a slight increase in the
mountains. Thus a generally 2 to 5 inches is expected at lower
elevations and 6 to 12 inches is expected in the mountains. Isolated
amounts around 16 inches will be possible in the mountains.
Temperatures will be mild Wednesday morning...but will fall rather
quickly Wednesday afternoon as colder air moves into the region
changing any rain back over to snow. For Friday and Saturday...it
will generally be cold with just a passing snow shower from time to
time. For Sunday and into early next week...the GFS13 and EC are
quite different. The EC model wants to start slowly warming things
up with little precipitation...while the GFS13 wants to bring down
significantly colder air and a better chance for precipitation. For
now I will go in the middle...but changes in the forecast are likely
to occur for this time period once model agreement starts to become
a bit more clear. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  47  30  39  20 /  40  20  20  20
CTB  43  27  37  20 /  30  20  10  10
HLN  45  29  37  16 /  80  30  30  20
BZN  42  24  33   8 /  70  40  40  20
WEY  38  21  31   4 / 100  80  50  30
DLN  44  28  35  12 /  80  50  30  10
HVR  44  28  40  20 /  90  40  30  20
LWT  47  29  37  19 /  80  40  30  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 5 PM MST this afternoon Central and
Southern Lewis and Clark...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5000 FEET FOR Central and Southern Lewis and Clark...
Jefferson...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.

WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5500 FEET FOR Beaverhead...Broadwater...Cascade...
Gallatin...Judith Basin...Madison...Meagher.

HIGH WIND WARNING until 10 PM MST this evening Cascade...
Chouteau...Fergus...Judith Basin.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








AREA FORECAST DISCUSSION

NWS GREAT FALLS MT

 956 AM MST Sun Dec 21 2014

.UPDATE...

MDOT highway cams reveal snow falling over area mountain passes
with reduced visibility as forecast. This snow will continue
through the day. Light freezing rain has been reported in Ft.
Belknap southeast of Havre. Light rain showers over this area
continue to move east with temperatures rising above freezing, so
expect this hazard to end by 11am. Wind gusts along the Rocky
Mountain Front are just now exceeding 60mph. Surface pressure is
beginning to rise along a line from Cut Bank to Great Falls to
Helena. Expect wind gusts to increase with these pressure rises
along the Rocky Mountain Front, then expand eastward into Central
Montana through the afternoon. HRRR guidance for wind gusts
supports strengthening wind gusts today. High wind warnings and
winter weather advisories for mountain snowfall remain in effect.
Updated temperatures and winds forecast for today to align closer
with observed trends. Nutter

&&

.AVIATION...
UPDATED 1138Z.
An upper level low pressure disturbance will bring increased cloud
cover and precipitation across Central and Southwest Montana through
tonight. Best chances for snow will be over the Rockies and
mountains of Southwest Montana. Local IFR/MVFR conditions will
continue through Monday along with areas of mountain obscuration.
Strong winds aloft will continue through today with 50kt winds
expected at ridge tops and mountain wave turbulence is likely. These
strong winds will also cause strong gusts at the surface today and
this evening.

&&

.PREV DISCUSSION...
/ISSUED 438 AM MST Sun Dec 21 2014/

Today through Tuesday...Strong west to northwest flow aloft today. A
shortwave will move through this flow and keep winds very strong.
Radar shows light precip over the western mountains. This
precipitation will spread east this morning as a low pressure
shortwave and associated cold front cross the Rockies. A surface low
pressure trof is over the CWA with higher pressure over Western. The
NAM gives 40 kt winds at just above the boundary level through the
day. Due to the position of the jet and timing of the front, will
cancel the current high wind watch but issue a warning for Lewis and
Clark, Cascade, Chouteau, Judith Basin, and Fergus counties. The
period of strongest winds will be associated with the frontal
passage. Will start Lewis and Clark warning with the issuance of
this forecast package, and start the others at 18z. The jet over the
Rockies will gradually shift to a more northwest direction during
the night. A ridge will build over the Eastern Pacific and northwest
flow aloft will be over the zones Monday. This ridge will be over
the Pacific Northwest by early Tuesday morning and move over the
zones during the day. The airmass will remain dry underneath the
high pressure but also remain rather cool. Zelzer

Tuesday night through Sunday...Expect another Pacific storm system
to move through the region from Tuesday night through Christmas Day.
Precipitation will be light to start with Tuesday night into
Wednesday morning...but will pick up in intensity by late Wednesday
afternoon through Christmas morning. It still looks like the swath
of heaviest snowfall will fall west of a line from Cut Bank to
Lewistown...with the Havre area only seeing around an inch of snow.
Otherwise...overall total snow accumulations still look to be on
track from previous forecasts...with a slight increase in the
mountains. Thus a generally 2 to 5 inches is expected at lower
elevations and 6 to 12 inches is expected in the mountains. Isolated
amounts around 16 inches will be possible in the mountains.
Temperatures will be mild Wednesday morning...but will fall rather
quickly Wednesday afternoon as colder air moves into the region
changing any rain back over to snow. For Friday and Saturday...it
will generally be cold with just a passing snow shower from time to
time. For Sunday and into early next week...the GFS13 and EC are
quite different. The EC model wants to start slowly warming things
up with little precipitation...while the GFS13 wants to bring down
significantly colder air and a better chance for precipitation. For
now I will go in the middle...but changes in the forecast are likely
to occur for this time period once model agreement starts to become
a bit more clear. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  47  30  39  20 /  40  20  20  20
CTB  43  27  37  20 /  30  20  10  10
HLN  45  29  37  16 /  80  30  30  20
BZN  42  24  33   8 /  70  40  40  20
WEY  38  21  31   4 / 100  80  50  30
DLN  44  28  35  12 /  80  50  30  10
HVR  44  28  40  20 /  90  40  30  20
LWT  47  29  37  19 /  80  40  30  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 5 PM MST this afternoon Central and
Southern Lewis and Clark...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5000 FEET FOR Central and Southern Lewis and Clark...
Jefferson...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.

WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5500 FEET FOR Beaverhead...Broadwater...Cascade...
Gallatin...Judith Basin...Madison...Meagher.

HIGH WIND WARNING until 10 PM MST this evening Cascade...
Chouteau...Fergus...Judith Basin.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 312 PM CST SUN DEC 21 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)

ISSUED AT 312 PM CST SUN DEC 21 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE
PLENTIFUL...RAIN CHANGING TO SNOW WEST THIS EVENING WITH
ACCUMULATIONS AND INCREASING WIND INTO MONDAY...AREAS OF FOG AND
PATCHY FREEZING DRIZZLE EAST...AND MORE ACCUMULATING SNOW
SOUTHEAST DEVELOPING MONDAY MORNING AND AFTERNOON.

CURRENTLY...INCOMING STORM SYSTEM ON THE NOSE OF A POWERFUL 150KT
+ UPPER LEVEL JET STREAK NOW OVER THE NORTHERN ROCKIES. ASSOCIATED
SURFACE LOW DEVELOPING AND MOVING SOUTHEAST FROM SOUTHERN ALBERTA
INTO EASTERN MONTANA. CURRENT PRECIPITATION ORIENTATED ALONG THE
SURFACE LOW`S WARM FRONT...FROM NORTH OF GLASGOW MT SOUTHEAST
INTO FAR SOUTHWESTERN NORTH DAKOTA. AREA OF LOW STRATUS AND FOG
ACROSS THE JAMES RIVER VALLEY CONTINUES TO SPREAD SLOWLY NORTH AND
WEST THANKS TO A MOIST SOUTHEASTERLY LOW LEVEL FLOW AHEAD OF THE
SFC LOW.

COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. AS THE
HRRR...NAM...AND RAP ALL INDICATE...STRATUS AND FOG NOW OVER THE
JAMES VALLEY WILL CONTINUE TO EXPAND WEST AND NORTH ACROSS THE
JAMES RIVER VALLEY INTO CENTRAL NORTH DAKOTA TONIGHT. WILL NEED
TO MONITOR VISIBILITIES IN CASE A DENSE FOG ADVISORY IS NEEDED FOR
THE JAMES VALLEY OR OTHER AREAS THIS EVENING. ALSO...MODELS
HINTING RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST. WITH
DRY AIR ALOFT OPTED TO MAINTAIN A MENTION OF FREEZING DRIZZLE WITH
THE STRATUS AND FOG UNTIL WE BECOME SATURATED OVERNIGHT.

POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON AND
EVENING...EVENTUALLY CHANGING TO ALL SNOW BY LATE EVENING. SNOW
CONTINUES ACROSS THE WEST AND EVEN REDEVELOPS ON MONDAY AS A
DEFORMATION ZONE AND ANOTHER MID LEVEL IMPULSE IMPACT THE AREA.
WITH CAA SNOW RATIOS WILL SUPPORT ACCUMULATING SNOWFALL OF 1 TO
NEAR 4 INCHES ACROSS THE SOUTHWEST. COMBINED WITH 15-25KTS OF WIND
ON THE BACKSIDE OF THE SFC LOW...OPTED TO HOIST A WINTER WEATHER
ADVISORY STARTING 06Z TONIGHT THROUGH 12Z TUESDAY.

ACROSS THE SOUTHEAST ON MONDAY...THE STORM SYSTEM PUSHING
SOUTHEAST TONIGHT WILL BE OVER WESTERN IOWA MONDAY...WRAPPING A
TROWAL BACK NORTHWEST AND THEN SOUTHWARD THROUGH THE EASTERN
DAKOTAS...INCLUDING THE JAMES RIVER VALLEY. TWO TO FOUR INCHES
WILL BE POSSIBLE THERE. WILL CONTINUE WITH THE SPS FOR THIS AREA
FOR NOW AND LET THE MID CREW DIGEST NEWER MODEL DATA. STILL SOME
UNCERTAINTY WITH QPF AND PLACEMENTS WITH MODELS NOT 100 PERCENT IN
AGREEMENT JUST YET.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 312 PM CST SUN DEC 21 2014

WINTER WEATHER MONDAY INTO TUESDAY...IMPACTING EARLY CHRISTMAS
TRAVEL FOR MUCH OF NORTH DAKOTA.

THE CURRENT MODEL SUITE PROVIDES GOOD AGREEMENT ON A STRONG LOW
PRESSURE SYSTEM BOTTOMING OUT OVER THE CENTRAL NORTHERN
PLAINS...KEEPING MUCH OF THE PRECIPITATION TO THE SOUTH AND EAST OF
NORTH DAKOTA. GOOD MODEL CONSENSUS ON TRACKING... THE SYSTEM IS
PROJECTED TO SLIDE SOUTH OVER NEBRASKA...THEN BEGIN TO TRACK
NORTHEASTWARD BY MONDAY NIGHT. AS THE SYSTEM TRACKS
NORTHEAST...BETWEEN TWO AND THREE INCHES OF SNOW IS FORECAST FOR
EASTERN AND SOUTHERN PORTIONS OF NORTH DAKOTA. OTHER AREAS COULD
RECEIVE UP TO AN INCH. BREEZY NORTHWESTERLY WINDS ARE ALSO FORECAST
ACROSS MUCH OF THE STATE...CREATING THE POTENTIAL FOR REDUCED
VISIBILITIES AND HAZARDOUS TRAVEL CONDITIONS.

SEASONAL TEMPERATURES ARE EXPECTED THROUGH MUCH OF THE EXTENDED.
THOUGH...ARCTIC LOW PRESSURE IS PROJECTED TO BEGIN SAGGING SOUTHWARD
FRIDAY...PRODUCING BELOW AVERAGE TEMPERATURES FRIDAY INTO SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)

ISSUED AT 312 PM CST SUN DEC 21 2014

PERIODS OF VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN
TERMINALS INCLUDING KJMS THROUGH MUCH OF THE PERIOD...WITH LOW
STRATUS AND FOG SPREADING SLOWLY NORTH AND WEST AND POSSIBLY
IMPACTING KBIS AND KMOT INTO THIS EVENING. LOW PRESSURE SYSTEM
WILL MOVE EAST AND BRING ANOTHER WARM FRONT EASTWARD ACROSS NORTH
DAKOTA TODAY. EXPECTING LIGHT RAIN AT KISN/KDIK THIS EVENING WITH
VFR CIGS...AND BETWEEN 02Z-06Z EXPECT PRECIPITATION TO CHANGEOVER
TO ALL SNOW. PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE
FORM OF -FZRA OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 06Z.
PREDOMINATELY VLIFR-IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT CST /11 PM MST/ TONIGHT TO
6 AM CST /5 AM MST/ TUESDAY FOR NDZ017-031>033-040-041-043-044.

&&

$$

SHORT TERM...NH
LONG TERM...AC
AVIATION...NH






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1206 PM CST SUN DEC 21 2014

.UPDATE...

ISSUED AT 1206 PM CST SUN DEC 21 2014

NO MAJOR CHANGES FROM THE MID MORNING UPDATE. LOW STRATUS
CONTINUES TO VERY SLOWLY EXPAND WEST AND NORTH ACROSS THE JAMES
RIVER VALLEY OF NORTH AND SOUTH DAKOTA...WITH INCREASING MID LEVEL
CLOUDS WEST TO EAST. CHANCES FOR RAIN ON TRACK TO ENTER WEST
CENTRAL AND SOUTHWEST ND BETWEEN NOW AND 21Z. VIS AT KJMS SLIGHTLY
IMPROVED SO NO HEADLINES BUT WILL CONTINUE TO MONITOR.


UPDATE
ISSUED AT 1049 AM CST SUN DEC 21 2014

COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. FOR THE MID MORNING
UPDATE MAIN CHANGE WAS TO INCREASE SKY COVER THROUGH THE DAY
ACROSS MY EAST ALONG WITH MENTIONING AREAS OF FOG. STRATUS
EXPANDING WEST AND NORTH ACROSS THE JAMES RIVER VALLEY WITH LOW
LEVEL MOISTURE ADVECTION WITH A SOUTH/SOUTHEAST WIND COMPONENT.
LAST FEW RUNS OF THE HRRR HANDLES THE STRATUS RATHER WELL SO WAS
UTILIZED. WILL NEED TO MONITOR VISIBILITIES IN CASE A DENSE FOG
ADVISORY IS NEEDED FOR THE JAMES VALLEY.

POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON WITH THE
INCOMING STORM SYSTEM. FOR TONIGHT...CONTINUED THE TREND OF
STRATUS AND FOG EXPANDING WEST AND NORTH. ALSO...MODELS HINTING
RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST IN ADDITION TO
THE LIKELY/DEF POPS WEST. WE LOOK DRY ALOFT OVER MY EAST SO OPTED
TO MENTION FREEZING DRIZZLE WITH THE STRATUS AND FOG UNTIL WE
BECOME SATURATED OVERNIGHT.

UPDATE ISSUED AT 650 AM CST SUN DEC 21 2014

NO CHANGE IN FORECAST THINKING FOR THE REMAINDER OF THE DAY WITH
THE INCOMING 06 UTC GUIDANCE. THUS...BLENDED THE ONGOING FORECAST
TO OBSERVED TRENDS THROUGH 12 UTC.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM CST SUN DEC 21 2014

FIRST CONCERN IN THE SHORT TERM IS LINGERING FOG IN THE JAMESTOWN
AREA...AND THE POSSIBILITY OF FOG REFORMING IN THE TURTLE MOUNTAINS
TO THE MINOT AREA.

CURRENTLY A SURFACE LOW WAS CENTERED OVER SOUTHERN ALBERTA. A WARM
FRONT EXTENDED FROM THE LOW ACROSS SOUTHERN SASKATCHEWAN INTO
EASTERN NORTH DAKOTA...ASSOCIATED WITH THE LINGERING STRATUS AND
FOG. ANOTHER WARM FRONT EXTENDED FROM THE LOW SOUTHEASTWARD INTO
CENTRAL MONTANA AND EASTERN WYOMING. AT UPPER LEVELS...THE
ASSOCIATED SHORTWAVE TROUGH WAS OVER THE CANADIAN AND NORTHERN US
ROCKIES.

THE LEADING EDGE OF THE UPPER LEVEL SHORTWAVE IS PROGGED TO REACH
WESTERN NORTH DAKOTA BY EARLY AFTERNOON. THIS TIMING IS ABOUT 6
HOURS SLOWER THAN INDICATED BY THE PREVIOUS MODEL RUNS. THE
PRECIPITATION SHOULD BE IN THE FORM OF RAIN IN WESTERN NORTH
DAKOTA...AS TEMPERATURES RISE INTO THE 30S AND LOWER 40S.

THIS EVENING THE AREA OF PRECIPITATION SHOULD EXPAND INTO CENTRAL
NORTH DAKOTA. THE RAIN IN THE WEST IS EXPECTED TO CHANGEOVER TO SNOW
DURING THE EVENING. CENTRAL NORTH DAKOTA WILL LIKELY SEE A BRIEF
PERIOD OF LIGHT FREEZING RAIN OR SLEET THIS EVENING BEFORE CHANGING
TO ALL SNOW BY LATE EVENING. TOTAL SNOW ACCUMULATIONS TONIGHT SHOULD
RANGE FROM AROUND AN INCH IN THE WILLISTON AREA TO LESSER AMOUNTS
ELSEWHERE. SEE THE LONG TERM DISCUSSION FOR THE BULK OF THE SNOW
FROM THIS SYSTEM.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM CST SUN DEC 21 2014

SNOWFALL POTENTIAL MONDAY INTO TUESDAY IMPACTING EARLY CHRISTMAS
TRAVEL HIGHLIGHTS THE EXTENDED FORECAST.

THE 00 UTC AND INCOMING 06 UTC DETERMINISTIC AND ENSEMBLE GUIDANCE
CONTINUES TO SHOW MODEST SPREAD IN THE PROPAGATION OF THE UPPER
LEVEL LOW ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST MONDAY INTO
TUESDAY. THE BEST COMPROMISE APPEARS TO BE THE 03 UTC
SREF...FOLLOWED BY THE 00 UTC ECMWF. THEIR SOLUTIONS SUGGEST TWO
AREAS OF POTENTIALLY MODERATE SNOWFALL ACCUMULATIONS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENT. THE FIRST IS WITH
A DEFORMATION ZONE ACROSS THE SOUTHWEST...AND THE SECOND ACROSS
THE JAMES RIVER VALLEY AND INTO FAR SOUTH CENTRAL NORTH DAKOTA
IN ASSOCIATION WITH THE TROWAL WITH THE UPPER LEVEL LOW. PER
COORDINATION WITH SURROUNDING OFFICES...WILL HIGHLIGHT THE EVENT
WITH AN SPS FOR...AND LET THE UPCOMING MODEL RUNS COME INTO A BIT
BETTER AGREEMENT IN THEIR MASS FIELDS. THEREAFTER...THE STORM
SYSTEM EXITS INTO THE GREAT LAKES FOR CHRISTMAS EVE...WITH
FAVORABLE TRAVEL CONDITIONS FOR NORTH DAKOTA INTO CHRISTMAS DAY.
TEMPERATURES WILL TREND BELOW AVERAGE LATE THIS COMING WEEK WITH A
MEAN LONG WAVE TROUGH ACROSS MUCH OF THE CONUS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)

ISSUED AT 1206 PM CST SUN DEC 21 2014

VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN TERMINALS INCLUDING
KJMS THROUGH THE PERIOD...WITH LOW STRATUS AND FOG SPREADING
SLOWLY NORTH AND WEST AND POSSIBLY IMPACTING KBIS AND KMOT LATER
TODAY INTO THIS EVENING. LOW PRESSURE SYSTEM WILL MOVE EAST AND
BRING ANOTHER WARM FRONT EASTWARD ACROSS NORTH DAKOTA TODAY.
EXPECTING LIGHT RAIN AT KISN/KDIK AFTER 18Z WITH VFR CIGS...AND
BETWEEN 01Z-04Z EXPECT PRECIPITATION TO CHANGEOVER TO ALL SNOW.
PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE FORM OF -FZRA
OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 06Z. PREDOMINATELY
VLIFR-IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY MORNING.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...NH







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1049 AM CST SUN DEC 21 2014

.UPDATE...

ISSUED AT 1049 AM CST SUN DEC 21 2014

COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. FOR THE MID MORNING
UPDATE MAIN CHANGE WAS TO INCREASE SKY COVER THROUGH THE DAY
ACROSS MY EAST ALONG WITH MENTIONING AREAS OF FOG. STRATUS
EXPANDING WEST AND NORTH ACROSS THE JAMES RIVER VALLEY WITH LOW
LEVEL MOISTURE ADVECTION WITH A SOUTH/SOUTHEAST WIND COMPONENT.
LAST FEW RUNS OF THE HRRR HANDLES THE STRATUS RATHER WELL SO WAS
UTILIZED. WILL NEED TO MONITOR VISIBILITIES IN CASE A DENSE FOG
ADVISORY IS NEEDED FOR THE JAMES VALLEY.

POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON WITH THE
INCOMING STORM SYSTEM. FOR TONIGHT...CONTINUED THE TREND OF
STRATUS AND FOG EXPANDING WEST AND NORTH. ALSO...MODELS HINTING
RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST IN ADDITION TO
THE LIKELY/DEF POPS WEST. WE LOOK DRY ALOFT OVER MY EAST SO OPTED
TO MENTION FREEZING DRIZZLE WITH THE STRATUS AND FOG UNTIL WE
BECOME SATURATED OVERNIGHT.


UPDATE ISSUED AT 650 AM CST SUN DEC 21 2014

NO CHANGE IN FORECAST THINKING FOR THE REMAINDER OF THE DAY WITH
THE INCOMING 06 UTC GUIDANCE. THUS...BLENDED THE ONGOING FORECAST
TO OBSERVED TRENDS THROUGH 12 UTC.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM CST SUN DEC 21 2014

FIRST CONCERN IN THE SHORT TERM IS LINGERING FOG IN THE JAMESTOWN
AREA...AND THE POSSIBILITY OF FOG REFORMING IN THE TURTLE MOUNTAINS
TO THE MINOT AREA.

CURRENTLY A SURFACE LOW WAS CENTERED OVER SOUTHERN ALBERTA. A WARM
FRONT EXTENDED FROM THE LOW ACROSS SOUTHERN SASKATCHEWAN INTO
EASTERN NORTH DAKOTA...ASSOCIATED WITH THE LINGERING STRATUS AND
FOG. ANOTHER WARM FRONT EXTENDED FROM THE LOW SOUTHEASTWARD INTO
CENTRAL MONTANA AND EASTERN WYOMING. AT UPPER LEVELS...THE
ASSOCIATED SHORTWAVE TROUGH WAS OVER THE CANADIAN AND NORTHERN US
ROCKIES.

THE LEADING EDGE OF THE UPPER LEVEL SHORTWAVE IS PROGGED TO REACH
WESTERN NORTH DAKOTA BY EARLY AFTERNOON. THIS TIMING IS ABOUT 6
HOURS SLOWER THAN INDICATED BY THE PREVIOUS MODEL RUNS. THE
PRECIPITATION SHOULD BE IN THE FORM OF RAIN IN WESTERN NORTH
DAKOTA...AS TEMPERATURES RISE INTO THE 30S AND LOWER 40S.

THIS EVENING THE AREA OF PRECIPITATION SHOULD EXPAND INTO CENTRAL
NORTH DAKOTA. THE RAIN IN THE WEST IS EXPECTED TO CHANGEOVER TO SNOW
DURING THE EVENING. CENTRAL NORTH DAKOTA WILL LIKELY SEE A BRIEF
PERIOD OF LIGHT FREEZING RAIN OR SLEET THIS EVENING BEFORE CHANGING
TO ALL SNOW BY LATE EVENING. TOTAL SNOW ACCUMULATIONS TONIGHT SHOULD
RANGE FROM AROUND AN INCH IN THE WILLISTON AREA TO LESSER AMOUNTS
ELSEWHERE. SEE THE LONG TERM DISCUSSION FOR THE BULK OF THE SNOW
FROM THIS SYSTEM.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM CST SUN DEC 21 2014

SNOWFALL POTENTIAL MONDAY INTO TUESDAY IMPACTING EARLY CHRISTMAS
TRAVEL HIGHLIGHTS THE EXTENDED FORECAST.

THE 00 UTC AND INCOMING 06 UTC DETERMINISTIC AND ENSEMBLE GUIDANCE
CONTINUES TO SHOW MODEST SPREAD IN THE PROPAGATION OF THE UPPER
LEVEL LOW ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST MONDAY INTO
TUESDAY. THE BEST COMPROMISE APPEARS TO BE THE 03 UTC
SREF...FOLLOWED BY THE 00 UTC ECMWF. THEIR SOLUTIONS SUGGEST TWO
AREAS OF POTENTIALLY MODERATE SNOWFALL ACCUMULATIONS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENT. THE FIRST IS WITH
A DEFORMATION ZONE ACROSS THE SOUTHWEST...AND THE SECOND ACROSS
THE JAMES RIVER VALLEY AND INTO FAR SOUTH CENTRAL NORTH DAKOTA
IN ASSOCIATION WITH THE TROWAL WITH THE UPPER LEVEL LOW. PER
COORDINATION WITH SURROUNDING OFFICES...WILL HIGHLIGHT THE EVENT
WITH AN SPS FOR...AND LET THE UPCOMING MODEL RUNS COME INTO A BIT
BETTER AGREEMENT IN THEIR MASS FIELDS. THEREAFTER...THE STORM
SYSTEM EXITS INTO THE GREAT LAKES FOR CHRISTMAS EVE...WITH
FAVORABLE TRAVEL CONDITIONS FOR NORTH DAKOTA INTO CHRISTMAS DAY.
TEMPERATURES WILL TREND BELOW AVERAGE LATE THIS COMING WEEK WITH A
MEAN LONG WAVE TROUGH ACROSS MUCH OF THE CONUS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)

ISSUED AT 1049 AM CST SUN DEC 21 2014

VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN TERMINALS INCLUDING
KJMS THROUGH THE PERIOD...WITH LOW STRATUS AND FOG SPREADING NORTH
AND WEST AND POSSIBLY IMPACTING KBIS AND KMOT LATER TODAY INTO
THIS EVENING. LOW PRESSURE SYSTEM WILL MOVE EAST AND BRING
ANOTHER WARM FRONT EASTWARD ACROSS NORTH DAKOTA TODAY. EXPECTING
LIGHT RAIN AT KISN/KDIK AFTER 18Z WITH VFR CIGS...AND BETWEEN
01Z-04Z EXPECT PRECIPITATION TO CHANGEOVER TO ALL SNOW.
PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE FORM OF -FZRA
OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 04Z. PREDOMINATELY VLIFR-
IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY MORNING.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...JV






AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 306 PM EST SUN DEC 21 2014

.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING.  SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY.  THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.

A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON.  THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.

MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY.  MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER.  THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN.  TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW.  THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.

THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB.  THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD.  THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.

THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.

USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
5H TROUGH TO DIG OVER THE MIDWEST WITH SEVERAL WAVES RIDING NWD
ALONG THE COAST OF SE US. THIS LEAVES OUR CWA IN THE WARM SECTOR
OF BAROCLINIC FORCING THAT WILL BE TAKING PLACE IN VARIOUS PHASES
THROUGHOUT THE PERIOD. FIRST WEAKER WAVE DEFTLY EXITS TO THE EAST
BY TUESDAY MORNING AND ONLY BROUGHT ISOLD AND LOW CHANCE POPS TO
THE EASTERN MOUNTAINS. WAA WILL BE FULL SWING UNDER SOUTH TO
SOUTHWEST FLOW AND CHANCES FOR ANY PRECIPITATION OF THE FROZEN
VARIETY WILL BE NIL.

A SECOND STRONGER WAVE WILL PUSH NORTH TUESDAY NIGHT AND
WEDNESDAY. MODELS STILL SHOW POOR PHASING BETWEEN NORTHERN AND
SOUTH STREAM SYSTEMS WITH MAIN SFC LOW DEVELOPMENT OCCURRING NORTH
OF THE GREAT LAKES. THIS DELAYS FROPA AND ONSET OF CAA AND PLACES
CWA SQUARELY IN THE WARM SECTOR THROUGH WEDNESDAY. FRONT WILL
FINIALLY PUSH THROUGH WEDNESDAY NIGHT WITH PRECIPITATION COMING TO
AN END...MOSTLY BEFORE THE COLDER AIR ON BACKSIDE IS ABLE TO MOVE
IN. THUS...ONLY HAVE VERY LIGHT SNOW AMOUNTS FIGURED FOR THE
MOUNTAINS IN NORTHEASTERN COUNTIES.

USED MAINLY SREF FOR TIMING ONSET OF PRECIP DEVELOPMENT. FOR
TEMPS...USED BC GRIDS WITH A BLEND TOWARD INHERITED FORECAST
TEMPS.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
COLD FRONT TO THE EAST OF THE CWA AT THE BEGINNING OF THE
PERIOD...WITH A GRADUAL CHANGE OVER TO SNOW FOR CHRISTMAS EVE NIGHT
AND CHRISTMAS DAY. AT THIS POINT...REALLY NOT EXPECTING MUCH IN
TERMS OF SNOWFALL ACCUMULATIONS. WINDS HOWEVER ON THURSDAY ARE STILL
EXPECTED TO BE GUSTY POST FRONTAL.

AREA DRIES OUT THURSDAY EVENING AS THE LOW PULLS OFF TO THE
NORTHEAST. HIGH PRESSURE THEN BRIEFLY BUILDS IN FOR A BREAK IN
PRECIPITATION. ANOTHER COLD FRONT WILL DROP ACROSS THE AREA OVER THE
WEEKEND...CREATING A CHANCE FOR LIGHT SNOW SHOWERS...AND WILL USHER
IN MUCH COLDER AIR INTO THE REGION. TRENDED TEMPERATURES NEXT
WEEKEND DOWN FROM PREVIOUS FORECAST.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.

A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON.  THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.

MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING.  CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.

LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON.  SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON.  FLOW ALOFT WILL REMAIN LIGHT S TO
SW.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.

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       20   21   22   23   00   01   02   03   04   05   06   07
EST 1HRLY       15   16   17   18   19   20   21   22   23   00   01   02
CRW CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    M    M    M    M    M    L    L    L    L
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    M    M    H    H    H    H    H    H    H
CKB CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...KMC
LONG TERM...SL
AVIATION...TRM









AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 158 PM EST SUN DEC 21 2014

.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING.  SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY.  THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.

A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON.  THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.

MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY.  MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER.  THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN.  TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW.  THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.

THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB.  THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD.  THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.

THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.

USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.

THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.

WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
COLD FRONT TO THE EAST OF THE CWA AT THE BEGINNING OF THE
PERIOD...WITH A GRADUAL CHANGE OVER TO SNOW FOR CHRISTMAS EVE NIGHT
AND CHRISTMAS DAY. AT THIS POINT...REALLY NOT EXPECTING MUCH IN
TERMS OF SNOWFALL ACCUMULATIONS. WINDS HOWEVER ON THURSDAY ARE STILL
EXPECTED TO BE GUSTY POST FRONTAL.

AREA DRIES OUT THURSDAY EVENING AS THE LOW PULLS OFF TO THE
NORTHEAST. HIGH PRESSURE THEN BRIEFLY BUILDS IN FOR A BREAK IN
PRECIPITATION. ANOTHER COLD FRONT WILL DROP ACROSS THE AREA OVER THE
WEEKEND...CREATING A CHANCE FOR LIGHT SNOW SHOWERS...AND WILL USHER
IN MUCH COLDER AIR INTO THE REGION. TRENDED TEMPERATURES NEXT
WEEKEND DOWN FROM PREVIOUS FORECAST.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.

A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON.  THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.

MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING.  CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.

LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON.  SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON.  FLOW ALOFT WILL REMAIN LIGHT S TO
SW.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.

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       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    M    M    M    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    M    M    M    M    M    L    L
EKN CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    M    M    M    M    H    H    H    H    H
CKB CONSISTENCY  M    M    M    M    M    M    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM









AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 145 PM EST SUN DEC 21 2014

.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING.  SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY.  THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.

A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON.  THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.

MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY.  MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER.  THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN.  TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW.  THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.

THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB.  THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD.  THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.

THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.

USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.

THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.

WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
ACTIVE WEATHER PATTERN CONTINUES IN THE LONG TERM PERIOD...WITH A
DEEPENING UPPER TROUGH ACROSS THE CENTRAL PLAINS AT THE BEGINNING OF
PERIOD...WITH A SURFACE LOW MOVING NORTHEAST OUT OF THE GULF STATES
TOWARDS THE REGION. STRONG SOUTHERLY WINDS WILL DEVELOP OUT AHEAD OF
THE SYSTEM...WITH GOOD MOISTURE TRANSPORT INTO THE AREA AS A RESULT.
THIS IS A STRONG SYSTEM...WITH STRONG PRESSURE FALLS/BOMBOGENESIS AS
THE LOW MOVES TOWARDS THE REGION. COLD FRONT STILL PROGGED TO MOVE
THROUGH THE AREA WEDNESDAY...WITH FALLING TEMPERATURES...STRONG
GUSTY WINDS ALONG AND BEHIND THE FRONT DUE TO TIGHT PRESSURE
GRADIENT...AND POTENTIAL FOR STRONG WINDS ALOFT TO MIX DOWN...AND
EVEN A SLIGHT CHANCE FOR THUNDER...MAINLY ACROSS THE WEST...AS THE
FRONT MOVES INTO THE REGION. STARTING TO LOOK MORE AND MORE LIKE
WINTER PRECIPITATION WILL NOT BE A HUGE HAZARD WITH THIS
SYSTEM...DUE TO THE OVERALL SPEED...AND THE FACT THAT BY THE TIME
ENOUGH COLD AIR IS IN PLACE...BULK OF MOISTURE SHOULD HAVE EXITED.
IN ADDITION...STILL QUITE A BIT OF UNCERTAINTY AS TO HOW MUCH WILL
ACTUALLY BE ABLE TO STICK TO THE GROUND IF GROUND TEMPERATURES ARE
TOO WARM AS TEMPERATURES WILL RISE INTO THE 50S OUT AHEAD OF THE
SYSTEM. HOWEVER...WILL STILL SEE A CHANGE OVER TO SNOW WEDNESDAY
NIGHT INTO THURSDAY...ALONG WITH FALLING TEMPERATURES. WILL CONTINUE
TO MAINTAIN HWO.

ON THURSDAY...UPPER LOW LIFTS NORTH ACROSS CANADA...BECOMING NEARLY
STACKED WITH SURFACE LOW. STILL A CHANCE FOR SOME LIGHT SNOW SHOWER
ACTIVITY ON THURSDAY...BUT WILL GRADUALLY SEE A DRYING TREND FROM
SOUTH TO NORTH AS THE SYSTEM PULLS AWAY.

ANOTHER FRONT APPROACHES LATE IN THE EXTENDED.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.

A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON.  THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.

MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING.  CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.

LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON.  SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON.  FLOW ALOFT WILL REMAIN LIGHT S TO
SW.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.

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       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    M    M    M    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    M    M    M    M    M    L    L
EKN CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    M    M    M    M    H    H    H    H    H
CKB CONSISTENCY  M    M    M    M    M    M    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM





AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 125 PM EST SUN DEC 21 2014

.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING.  SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY.  THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.

A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON.  THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.

MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY.  MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER.  THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN.  TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW.  THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.

THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB.  THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD.  THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.

THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.

USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.

THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.

WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
ACTIVE WEATHER PATTERN CONTINUES IN THE LONG TERM PERIOD...WITH A
DEEPENING UPPER TROUGH ACROSS THE CENTRAL PLAINS AT THE BEGINNING OF
PERIOD...WITH A SURFACE LOW MOVING NORTHEAST OUT OF THE GULF STATES
TOWARDS THE REGION. STRONG SOUTHERLY WINDS WILL DEVELOP OUT AHEAD OF
THE SYSTEM...WITH GOOD MOISTURE TRANSPORT INTO THE AREA AS A RESULT.
THIS IS A STRONG SYSTEM...WITH STRONG PRESSURE FALLS/BOMBOGENESIS AS
THE LOW MOVES TOWARDS THE REGION. COLD FRONT STILL PROGGED TO MOVE
THROUGH THE AREA WEDNESDAY...WITH FALLING TEMPERATURES...STRONG
GUSTY WINDS ALONG AND BEHIND THE FRONT DUE TO TIGHT PRESSURE
GRADIENT...AND POTENTIAL FOR STRONG WINDS ALOFT TO MIX DOWN...AND
EVEN A SLIGHT CHANCE FOR THUNDER...MAINLY ACROSS THE WEST...AS THE
FRONT MOVES INTO THE REGION. STARTING TO LOOK MORE AND MORE LIKE
WINTER PRECIPITATION WILL NOT BE A HUGE HAZARD WITH THIS
SYSTEM...DUE TO THE OVERALL SPEED...AND THE FACT THAT BY THE TIME
ENOUGH COLD AIR IS IN PLACE...BULK OF MOISTURE SHOULD HAVE EXITED.
IN ADDITION...STILL QUITE A BIT OF UNCERTAINTY AS TO HOW MUCH WILL
ACTUALLY BE ABLE TO STICK TO THE GROUND IF GROUND TEMPERATURES ARE
TOO WARM AS TEMPERATURES WILL RISE INTO THE 50S OUT AHEAD OF THE
SYSTEM. HOWEVER...WILL STILL SEE A CHANGE OVER TO SNOW WEDNESDAY
NIGHT INTO THURSDAY...ALONG WITH FALLING TEMPERATURES. WILL CONTINUE
TO MAINTAIN HWO.

ON THURSDAY...UPPER LOW LIFTS NORTH ACROSS CANADA...BECOMING NEARLY
STACKED WITH SURFACE LOW. STILL A CHANCE FOR SOME LIGHT SNOW SHOWER
ACTIVITY ON THURSDAY...BUT WILL GRADUALLY SEE A DRYING TREND FROM
SOUTH TO NORTH AS THE SYSTEM PULLS AWAY.

ANOTHER FRONT APPROACHES LATE IN THE EXTENDED.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.

A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON.  THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.

MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING.  CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.

LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON.  SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON.  FLOW ALOFT WILL REMAIN LIGHT S TO
SW.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.

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       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    M    M    M    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    M    M    M    M    M    L    L
EKN CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    M    M    M    M    H    H    H    H    H
CKB CONSISTENCY  M    M    M    M    M    M    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM






AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 303 PM EST SUN DEC 21 2014

.SYNOPSIS...
A MOIST AIR MASS WILL REMAIN ACROSS THE REGION BEFORE A COLD FRONT
CROSSES EAST ON WEDNESDAY. DRY CANADIAN HIGH PRESSURE WILL BUILD IN
THURSDAY AND PERSIST INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 230 PM...THE STRATUS DECK CONTINUES TO ERODE SLOWLY ACRS THE
MTNS AND LOWER PIEDMONT THIS AFTN...RESULTING IN SLIGHTLY WARMER
TEMPS UNDER MORE SUNSHINE. MOST THE AREA IS STILL OVERCAST OR MOSTLY
CLOUDY...WITH TEMPS IN THE 40S TO LWR 50S.

GUIDANCE IN GOOD AGREEMENT ON A DIGGING TROF TO THE WEST AND A
BUILDING RIDGE ALONG THE EAST COAST TONIGHT THRU MONDAY. SHORTWAVE
ENERGY WILL RIDE FROM SW TO NE THRU THE FLOW ATOP THE SOUTHEAST
STATES...INDUCING A WEAK WAVE ALONG A COASTAL FRONT OFF THE SC COAST
ON MONDAY. INCREASING SOUTHERLY UPGLIDE AND 850 MB WAA FLOW ATOP THE
CWFA. POPS QUICKLY RAMP UP TO CATEGORICAL ACRS THE SOUTHERN HALF OF
THE CWFA...AND LIKELY TO THE NORTH BY LATE EVENING. THE COVERAGE
WILL BE AIDED BY SOME DEEP LAYER Q-VECTOR CONVERGENCE WITHIN THE
SWLY MID-UPR FLOW. HOWEVER...THE MOISTURE DEPTH WILL BE FAIRLY
SHALLOW...AND FORCING OVERALL WEAK. SO QPF AMOUNTS SHUD BE GENERALLY
A FEW HUNDREDTHS TO A TENTH OF AN INCH. ALTHO...A TENTH TO QUARTER
INCH POSSIBLE AROUND THE CHARLOTTE METRO AREA. ONE THING TO MENTION
IS THAT THERMAL PROFILES ARE MARGINAL FOR SOME FREEZING RAIN AND
SLEET ACRS THE NRN MTNS...MAINLY AVERY COUNTY. THE 12Z NAM AND
LATEST RAP KEEP THINGS JUST ABOVE FREEZING. I WOULDN/T BE SURPRISED
IF A FEW SPOTS NEAR THE EASTERLY UPSLOPE AREAS IN AVERY/CALDWELL MAY
HAVE BRIEF FZRA/DZ TOWARD DAYBREAK MONDAY. HOWEVER...CONFIDENCE IS
JUST NOT HIGH ENUF TO ISSUE A FREEZING RAIN ADVISORY AT THIS TIME.
IF THE 18Z NAM COMES IN COLDER...OR IF TRENDS SEEM TO WARRANT
IT...THE EVENING SHIFT MAY WANT TO ISSUE ONE OR AN SPS.
OTHERWISE...IT SHUD BE JUST A COLD RAIN WITH TEMPS IN THE 30S TO LWR
40S.

ON MONDAY...THE MID LVLS DRY OUT...AND THE BETTER FORCING EXITS TO
THE EAST. HOWEVER...A WEDGE IS EXPECTED TO REMAIN...WITH LLVL
UPGLIDE CONTINUING WITHIN SWLY FLOW. THIS LOOKS LIKE A GOOD SETUP
FOR AREAS OF -DZ PERSISTING...ALSO KEEPING TEMPS DOWN. GOING CLOSE
TO THE RAW MODEL TEMPS FOR HIGHS...AND KEEPING A CHC OF -RA AND DZ
THRU THE DAY. HIGHS WILL LIKELY STRUGGLE TO GET INTO THE 40S ACRS
THE I-40 CORRIDOR...AND ONLY THE MID TO UPR 40S ELSEWHERE.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM EST SUNDAY...MON NIGHT THROUGH TUESDAY NIGHT...LATEST
12Z MODELS CONTINUE TO INDICATE THAT SURFACE COLD AIR DAMMING WEDGE
WILL CONTINUE ACROSS THE AREA AS 1030MB HIGH WILL REMAIN ANCHORED
OVER THE NE. MEANWHILE...STRONG SSWLY FLOW ALOFT DEVELOPS ACROSS THE
SE BY TUE AS A DEEP UPPER TROUGH MOVES EAST ACROSS THE CENTRAL CONUS
WHILE AN UPPER RIDGE AMPLIFIES OVER THE WESTERN ATLANTIC. THIS WILL
LEAD TO INCREASING 290K ISENTROPIC LIFT/ATLANTIC MOISTURE ADVECTION
OVER OUR CWA THRU TUESDAY. HENCE...HAVE CARRIED CHANCE POPS FOR
LIGHT RAIN WITH DRIZZLE MON NIGHT INTO TUE MORNING...RAMPING UP INTO
THE CATEGORICAL POPS WITH STEADY RAIN TOWARDS TUE NIGHT. WITH
ONGOING PRECIP WITHIN THE CAD...AFTERNOON TEMPS ON TUE WILL RUN 7-10
DEGREES BELOW NORMAL OVER THE PIEDMONT WITH 3-5 DEGREES BELOW OVER
THE WESTERN NC MTNS.

WEDNESDAY...THE UPPER TROUGH OVER THE MISSISSIPPI VALLEY WILL
ADVANCE EASTWARD...BECOMING POSITIVELY TILED AS IT PUSHES THROUGH
THE EASTERN CONUS. THIS WILL LIFT A SURFACE LOW INTO THE OHIO VALLEY
BY 18Z...PUSHING ITS ASSOCIATED COLD FRONT THROUGH THE FORECAST AREA
BETWEEN 18Z WED AND 00Z THU. ALTHOUGH THERE WILL BE STRONG LLVL WIND
SHEAR ALONG AND AHEAD OF THE FRONT...THE BEST UPPER FORCING WILL NOT
REACH THE AREA UNTIL 00Z THU AND AREAS SBCAPE REGIME WILL REMAIN
SOUTH OF THE AREA. THEREFORE...HIGH SHEAR LOW CAPE SEVERE EVENT
APPEARS LOW AT THIS TIME. AS FOR QPF...MODELS STILL DEPICT
WIDESPREAD CONVECTIVE ACTIVITY ALONG THE GULF COAST/SE COAST...WHICH
COULD BLOCK DEEP MOISTURE TRANSPORT INTO OUR AREA. WITH THE
UNCERTAINTY...HAVE GONE WITH THE MODEL CONSENSUS QPF...YIELDING 1-2
INCHES ACROSS THE REGION WITH UP TO 3" OVER THE BLUE RIDGE
ESCARPMENT. CATEGORICAL POPS WERE HIGHLIGHTED THRU 18Z WED...
QUICKLY RAMPING DOWN TO THE CHANCE RANGE FROM WEST TO EAST THRU 00Z
THU AS THE FRONT PUSHES TO THE EAST. WITH INCREASING WAA
FLOW...AFTERNOON TEMPS WILL WARM INTO THE U50S/60S EAST OF THE MTNS
AND 50S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...THE LATE WEEK WILL SEE THE SHARP UPPER TROUGH
PUSH OFF THE EAST COAST...LEAVING QUASI-ZONAL FLOW OVER THE ERN THIRD
OF THE CONUS. DRY HIGH PRESSURE WILL CROSS THE SOUTHEAST BEFORE
HEIGHTS FALL OVER THE MISSISSIPPI VALLEY AS NEXT LOW ROLLS OFF THE
ROCKIES AND ACRS THE GREAT LAKES. DIFFERENCES BETWEEN THE GFS AND EC
ARE MINOR IN TERMS OF SENSIBLE WX CHRISTMAS DAY AND FRIDAY...BOTH
INDICATING NW FLOW PRECIP TAPERING OFF CHRISTMAS MRNG FOLLOWED BY DRY
WX MOST OF FRIDAY. IN COLD ADVECTIVE PATTERN HIGHER ELEVATIONS WILL
LIKELY SEE BREEZY/GUSTY CONDITIONS ON CHRISTMAS. THE COLD FRONT
ASSOCIATED WITH THE GRT LAKES LOW WILL ARRIVE BY FRIDAY NIGHT ALBEIT
WITHOUT MUCH OOMPH...THE GFS PRETTY MUCH WASHING THE FRONT OUT OVER
THE CAROLINAS. THE EC HOWEVER DIVERGES AT THIS POINT...STALLING THE
FRONT ALONG THE COAST AND EVENTUALLY DEVELOPING A COASTAL LOW NEAR
THE OUTER BANKS SUNDAY IN RESPONSE TO A SRN STREAM SHORTWAVE TRAILING
THE FRONT. BOTH THE 21/00Z AND 21/12Z RUNS FEATURE THIS EVOLUTION. SO
WHILE THE GFS WOULD SUGGEST NEXT WEEKEND WILL BE QUIET AND DRY...EC
INDICATES SOME PTYPE ISSUES MAY EXIST SUNDAY WITH WINTRY PARTIAL
THICKNESSES AND THERMAL PROFILES. TEMPS WILL BE AT OR A LITTLE ABOVE
CLIMO FROM THU-SAT...AND BELOW NORMAL SUNDAY IF THE CLOUDS/PRECIP
MATERIALIZE.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AT KCLT...THE MVFR CIGS HAVE FINALLY SCATTERED OUT...BUT SOME
CONTINUE TO LINGER TO THE NORTH AND WEST OF THE TERMINAL THIS AFTN.
LOW VFR CLOUDS WILL CONTINUE THRU THE AFTN. THEN MVFR CIG  RETURN BY
EARLY EVENING. LIGHT RAIN IS EXPECTED TO DEVELOP TONIGHT AS A
SURFACE LOW MOVES UP THE COAST. IFR CIGS AND MVFR VSBY EXPECTED WITH
THE PRECIP. RAIN WILL TAPER OFF BY LATE MONDAY MORNING...BUT LOW
CLOUDS AND DRIZZLE WILL LINGER THRU AT LEAST MIDDAY. WINDS ARE
EXPECTED TO FAVOR THE NE THRU THE PERIOD...AS WEAK COLD AIR DAMMING
REGIME DOMINATES.

ELSEWHERE...CIGS HAVE BEEN VARIABLE ACRS THE REGION TODAY...AND IT
WILL PROBABLY CONTINUE THAT WAY THRU THE REST OF THE AFTN...PER
SATELLITE TRENDS. GENERALLY MVFR TO OCCASIONAL VFR CONDITIONS
EXPECTED. THEN CONDITIONS WILL DETERIORATE THIS EVENING...AS
MOISTURE AND PRECIP MOVES IN FROM THE SOUTHWEST...AS A SFC LOW MOVES
UP THE COAST. CIGS ARE EXPECTED TO GO TO IFR...WITH SOME VSBY
RESTRICTIONS POSSIBLE UNDER -RA AND DZ. THE LIGHT RAIN WILL TAPER OFF
MONDAY MORNING...BUT AREAS OF -DZ WILL LIKELY LINGER THRU AT LEAST
MIDDAY...ESP ACRS THE UPSTATE. WINDS WILL CONTINUE IN THE USUAL COLD
AIR DAMMING PATTERN...WITH LIGHT NE WINDS EAST OF THE MTNS AND SE AT
KAVL.

OUTLOOK...LINGERING LOW LEVEL MOISTURE IS LIKELY TO KEEP LOW STRATUS
AROUND THRU MONDAY. A COLD FRONT WILL APPROACH ON TUESDAY FROM THE
WEST AND MOVE THROUGH ON WED. WIDESPREAD SHOWERS WITH RESTRICTIONS
SHOULD ARRIVE TUESDAY AFTERNOON AND WILL CONTINUE UNTIL THE FRONT
CLEARS THE AREA LATE WEDNESDAY.

CONFIDENCE TABLE...

            20-02Z        02-08Z        08-14Z        14-18Z
KCLT       HIGH 100%     MED   72%     LOW   54%     MED   78%
KGSP       HIGH  94%     LOW   54%     MED   73%     HIGH  81%
KAVL       HIGH  80%     HIGH  87%     MED   76%     HIGH  87%
KHKY       HIGH  98%     HIGH  82%     MED   72%     HIGH  85%
KGMU       HIGH  96%     LOW   58%     MED   73%     HIGH  81%
KAND       HIGH  92%     LOW   46%     MED   67%     HIGH  87%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...SBK
NEAR TERM...ARK
SHORT TERM...JOH
LONG TERM...WIMBERLEY
AVIATION...ARK






AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 323 PM CST SUN DEC 21 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 323 PM CST SUN DEC 21 2014

CLEARING LINE HAS MADE SOME PROGRESS EAST THIS AFTERNOON. HOWEVER BY
LATE THIS AFTERNOON AND EVENING EXPECT THE LOW STRATUS TO RETURN
NORTHWEST AND COVER MUCH OF THE AREA YET AGAIN. HRRR AND RAP
GUIDANCE HAVE BEEN DOING PRETTY WELL THE PAST FEW NIGHTS...AND
SUGGEST DENSE FOG WILL PROBABLY NOT BE AS BIG OF AN ISSUE TONIGHT. A
STRONG UPPER WAVE WILL DIVE SOUTHEAST INTO THE PLAINS TONIGHT. STILL
QUITE THE SPREAD AMONG MODEL SOLUTIONS. NAM AND GFS ARE FURTHER
SOUTH WITH THE SYSTEM THAN THE ECMWF. ECMWF HAS BEEN THE MOST
CONSISTENT AND THE PARALLEL UPGRADED GFS IS MORE IN LINE WITH THE
ECMWF SOLUTION. THUS DECIDED TO WEIGH HEAVILY IN THAT DIRECTION FOR
THIS FORECAST. LIFT AHEAD OF THE WAVE WILL LIKELY GENERATE
PRECIPITATION TONIGHT...DEVELOPING IN THE WEST THIS EVENING...AND
SPREADING EAST THROUGH THE NIGHT. BASED ON MODEL SOUNDINGS AND
CONSENSUS RAW TEMPERATURES...BELIEVE THIS WILL MAINLY BE RAIN.
ALTHOUGH COULD SEE SOME SLEET MIXED IN...MAINLY WEST OF THE JAMES
RIVER.

MONDAY IS WHEN THE MODEL DIFFERENCES BEGIN TO HAVE A BIGGER IMPACT
ON THE FORECAST. THE FAVORED ECMWF AND PARALLEL GFS SOLUTION RESULTS
IN A DRY SLOT OVER MUCH OF THE CWA. THE MAJORITY OF THE WRAP AROUND
SNOW ASSOCIATED WITH THE DEVELOPING TROWAL SHOULD STAY NORTHWEST OF
THE CWA. DO THINK LOCATIONS FROM HURON TO CHAMBERLAIN COULD GET IN
ON SOME OF THIS ACTIVITY THOUGH. SOUNDINGS SUGGEST THAT BY MONDAY
ANY WARM LAYER IS SURFACE BASED...SUGGESTING EITHER RAIN OR SNOW
DEPENDING ON SURFACE TEMPERATURE. RAW MODEL CONSENSUS OF
TEMPERATURES SUGGESTS PTYPE STAYS PREDOMINATELY RAIN EAST OF THE
JAMES RIVER INTO THE AFTERNOON...WITH THE RAIN SNOW MIX GETTING TO
INTERSTATE 29 BY 0Z. BUT AS MENTIONED...MUCH OF THE CWA SHOULD SEE
VERY LIMITED QPF THROUGH THE DAY HOURS...WITH JUST SOME RAIN IN THE
FAR EAST AND AN INCH OR TWO OF SNOW FROM BRULE TO WESTERN BEADLE
COUNTY. WILL NEED TO MONITOR MODEL TRENDS...BECAUSE IF THE NAM AND
OPERATIONAL GFS FURTHER SOUTH SOLUTION VERIFIES...MORE OF THE CWA
WOULD SEE PRECIP ON MONDAY. BUT EVEN THEN THE WARM LOW LEVEL
TEMPERATURES WOULD LIKELY KEEP MOST AREAS RAIN FOR A MAJORITY OF THE
DAY KEEPING ANY SNOW ACCUMS DOWN.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 323 PM CST SUN DEC 21 2014

MONDAY NIGHT INTO TUESDAY WILL BE A PERIOD WHERE THE SYSTEM HAS
SLOWED DOWN JUST A BIT AND A FAIRLY PERSISTENT TROWAL SETS UP.
STRONG NORTH TO NORTHWEST WINDS WILL GRADUALLY DEVELOP THROUGH THE
DAY SO IT IS STARTING TO LOOK LIKE WE MAY NEED AND ADVISORY FOR SNOW
AND BLOWING SNOW MONDAY NIGHT INTO TUESDAY. MODELS STILL HAVE JUST
ENOUGH DISAGREEMENT AND THE WORST CONDITIONS LOOK TO BE LATE THIRD
PERIOD INTO 4TH PERIOD SO WILL HOLD OFF ON ISSUING ANY HEADLINES BUT
IF THIS EVENINGS MODELS COME IN SIMILAR WILL LIKELY NEED SOMETHING.
MONDAY EVENING WILL START OFF RELATIVELY MILD IN THE SOUTHEAST WITH
TEMPERATURES ABOVE FREEZING SO A BETTER CHANCE FOR RAIN IN NORTHWEST
IOWA BEFORE MIDNIGHT BUT BY ABOUT 11PM TO MIDNIGHT SHOULD BE COLD
ENOUGH FOR SNOW. NO CONCERNS RIGHT NOW OF MIXED PRECIPITATION MONDAY
NIGHT AS THE WARM LAYER IS AT THE GROUND SO SHOULD BE EITHER RAIN OR
SNOW. WENT AHEAD AND INCREASED POPS TONIGHT INTO TUESDAY AND
INCREASED QPF AMOUNTS SOME SO THAT BY TUESDAY EVENING SO THAT MUCH
OF THE AREA SHOULD SEE 2 TO 4 INCHES WITH THE JAMES VALLEY WEST
SEEING THE BEST CHANCE AT APPROACHING 4 INCHES. AGAIN...WITH 2 TO 4
INCHES OF SNOW AND 20 TO 35 MPH WINDS ON TUESDAY AND TUESDAY NIGHT
HAZARDOUS TRAVEL IS LOOKING MORE LIKELY TUESDAY INTO WEDNESDAY.

BY WEDNESDAY EVERYTHING SHOULD BE TO THE EAST OF THE AREA AND WINDS
WILL DIMINISH THROUGH THE DAY. CLOUD COVER SHOULD ALSO BREAK UP A
BIT...AT LEAST GETTING DOWN TO MOSTLY CLOUDY. WITH FRESH SNOW ON THE
GROUND EXPECTING HIGHS MAINLY IN THE 20S.

IN THE OUTER PERIODS (THURSDAY THROUGH SUNDAY)...STILL AN
INTERESTING SYSTEM COMING THROUGH ON THURSDAY NIGHT INTO FRIDAY. THE
12Z GFS SEEMED A BIT OUT TO LUNCH BUT THE 12Z ECMWF AND THE 12Z
PARALLEL GFS BOTH AGREED WELL AND SHOWED SOME CONSISTENCY FROM
YESTERDAYS RUNS. UNFORTUNATELY THE SUPERBLEND IS POLLUTED WITH THE
12Z GFS SO POPS CAME IN MUCH LOWER. HAVING TROUBLE COLLABORATING
HIGHER POPS BUT RIGHT NOW ANTICIPATE THAT POPS WILL NEED TO BE
INCREASED FOR ESPECIALLY THURSDAY NIGHT. AFTER THIS STARTING TO LOOK
LIKE A PERIOD OF COLDER WEATHER WILL SETTLE IN AS A LARGE SCALE
TROUGH SETS UP NORTHERLY FLOW ALOFT INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. SO ANTICIPATING HIGHS IN THE TEENS AND 20S FRIDAY
INTO SUNDAY WITH LOWS IN THE SINGLE DIGITS...POSSIBLY DIPPING BELOW
ZERO ASSUMING PARALLEL AND ECMWF ARE MORE ON TARGET. SO WENT AHEAD
AND DROPPED SUPERBLEND LOWS ABOUT 2 TO 4 DEGREES IN MOST LOCATIONS
SATURDAY MORNING AND SUNDAY MORNING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CST SUN DEC 21 2014

LIFR TO IFR CIGS AND VIS CONTINUE OVER A GOOD PORTION OF THE AREA.
CLEARING STARTING TO MAKE PROGRESS EAST...CURRENTLY NEAR THE
JAMES RIVER. THIS CLEARING COULD MAKE IT AS FAR EAST AS KHON OR
KFSD...SO WILL CONTINUE TO MONITOR TRENDS. FOR NOW WILL KEEP THE
TAFS PESSIMISTIC AS STILL THINK THAT IS THE MORE LIKELY SOLUTION.
WILL SEE RAIN DEVELOP LATER TONIGHT...POSSIBLY MIXED WITH SOME
SLEET. CIGS COULD BUMP UP INTO IFR OR LOW END MVFR AFTER THE RAIN
STARTS...AND VIS SHOULD NOT BE AS BAD AS THIS MORNING. RAIN WILL
SLOWLY TRANSITION TO SNOW...BUT THINK AREAS EAST OF THE JAMES
RIVER WILL PROBABLY BE PREDOMINATELY RAIN THROUGH 18Z.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHENARD
LONG TERM...08
AVIATION...CHENARD



AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 1150 AM CST SUN DEC 21 2014

.AVIATION...
STRATUS CLEARED KCDS EARLIER WITH VFR CONDITIONS EXPECTED TO
PREVAIL AT ALL TAF SITES THROUGH THE PERIOD. SFC LEE TROUGH
DEVELOPING OVER ERN NM WILL KEEP WESTERLY WINDS UP THIS AFTERNOON.
WINDS VEER OVERNIGHT AS TROUGH MOVES EAST.

&&

PREV DISCUSSION... /ISSUED 434 AM CST SUN DEC 21 2014/

SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.

SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.

LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.

PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.

AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.

JORDAN

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        34  56  25  41  22 /   0   0  50   0   0
TULIA         35  56  28  42  24 /   0   0  50   0   0
PLAINVIEW     36  58  29  42  25 /   0   0  50  10   0
LEVELLAND     37  63  30  44  26 /   0   0  50  10   0
LUBBOCK       38  61  31  44  26 /   0   0  50  10   0
DENVER CITY   39  68  32  46  27 /   0   0  50  10   0
BROWNFIELD    38  67  32  45  27 /   0   0  50  10   0
CHILDRESS     37  59  35  48  29 /   0   0  30  10   0
SPUR          39  63  36  48  30 /   0   0  40  10   0
ASPERMONT     42  67  38  51  31 /   0   0  40  10   0

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

93/14/24





AREA FORECAST DISCUSSION

NWS AUSTIN/SAN ANTONIO TX

 1102 AM CST SUN DEC 21 2014

.AVIATION...
IFR/MVFR CIGS CONTINUE TO ENCOMPASS SOUTH CENTRAL TEXAS. KAUS AND
KSAT HAVE LIFTED INTO MVFR WHILE KSSF AND KDRT CONTINUE WITH IFR
CONDITIONS. THESE TWO SITES SHOULD IMPROVE WITHIN THE NEXT HOUR
OR TWO. MVFR WILL CONTINUE FOR MOST OF THE REMAINDER OF THE
AFTERNOON AND EVENING. MODELS SEEM TO BE TOO OPTIMISTIC WITH
LIFTING THE CIGS TO 5KFT AND WILL KEEP HIGHER MVFR PREVAILING.
SHOULD SEE CIGS LOWER INTO LOW MVFR THEN POSSIBLY IFR ONCE AGAIN
TOMORROW MORNING. THE WIND COMPONENT WILL BECOME MORE
SOUTHWESTERLY TOMORROW WHICH SHOULD BEGIN TO SCATTER THINGS OUT A
BIT BETTER.

HAMPSHIRE

&&

.PREV DISCUSSION... /ISSUED 950 AM CST SUN DEC 21 2014/

UPDATE...
OVERCAST SKIES CONTINUE ACROSS ALL OF SOUTH CENTRAL TEXAS.
OVERRUNNING CONDITIONS WILL CONTINUE TODAY AS SURFACE RIDGE AXIS
ALONG THE COASTAL PLAINS SLOWLY SHIFTS EAST AND RETURN FLOW
DEVELOPS AT THE SURFACE AND MID LEVELS. THIS OVERRUNNING WILL ALLOW FOR
SOME LIGHT PATCHY DRIZZLE THE NEXT HOUR OR SO IN A FEW SPOTS BUT
NOT HEAVY ENOUGH TO MENTION IN THE FORECAST AT THIS TIME. MODELS
SHOW THE OVERRUNNING CLOUDS WILL CONTINUE OVER THE EASTERN HALF OF
THE CWA ALL DAY WHILE THINNER MOISTURE OUT WEST WILL MIX OUT BY
THE AFTERNOON GIVING WAY TO SOME SUNSHINE. LATEST HRRR MODELS
SHOWS THIS AS WELL. MADE SOME MINOR ADJUSTMENTS TO THE GRIDS BUT
OVERALL CURRENT FORECAST TREND IS GOOD.

PREV DISCUSSION... /ISSUED 535 AM CST SUN DEC 21 2014/

AVIATION.../12Z TAF CYCLE/
MVFR PREVAILS ACROSS CENTRAL TAF SITES WITH STRATUS OVC015 CIGS ON
AVERAGE WITH LOWER IFR CIGS AT KDRT NEAR 600FT AS OF 12Z. EXPECT
KDRT TO IMPROVE THROUGH LATE MORNING/AFT TO VFR. CENTRAL SITES WILL
BE TRICKY WITH MODEL GUIDANCE IN DISAGREEMENT ON WHETHER VFR
CONDITIONS WILL RETURN FEEL STRATUS DECK WILL ERODE IN WEST TEXAS
AND WITH WEAK S/SW FLOW WILL HELP MORE CLEARING TOWARDS KSAT/KSSF
THAN YESTERDAY BUT IT WILL BE CLOSE. FEEL KAUS HAS LEAST CHANCE OF
GOING VFR WITH HIGH END MVFR THROUGH THE AFTERNOON. EXPECT CENTRAL
SITES TO FALL BACK TO LOW MVFR TO POSSIBLY IFR OVERNIGHT. HAVE
FOLLOWED MORE OF NAM/RAP CONSISTENCY FOR KDRT WITH MVFR POSSIBLY
RETURNING OVERNIGHT AS WELL. MUCH QUICKER CLEARING EXPECTED MONDAY
WITH VFR LIKELY FOR ALL SITES BY NOON.

SURFACE WINDS WILL BE S/SW AT 10 KT OR LESS THROUGH THE AFTERNOON
AND OVERNIGHT. /ALLEN/

PREV DISCUSSION... /ISSUED 357 AM CST SUN DEC 21 2014/

SHORT TERM (TODAY THROUGH MONDAY)...
PATCHY FOG HAS DEVELOPED IN SOME SPOTS AND WILL MAINTAIN MENTION
THROUGH MID MORNING. AN UPPER LEVEL TROUGH DEVELOPING OVER THE
CENTRAL STATES GETS AN ENHANCEMENT FROM A COUPLE SHORT-WAVES
MOVING ACROSS TEXAS AND A STRONGER SHORT-WAVE CURRENTLY MOVING
INTO THE PACIFIC NORTHWEST. WEAK ISENTROPIC LIFT MAINTAINS MOSTLY
CLOUDY SKIES AND NEAR AVERAGE TEMPERATURES TODAY. A SOUTHWESTERLY
LOWER LEVEL FLOW DEVELOPS ON MONDAY AS SURFACE LOW STRENGTHENS IN
THE PLAINS LEADING TO WELL ABOVE AVERAGE TEMPERATURES AND WARMEST
OF THE NEXT WEEK AS CLOUDS ERODE.

LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
THE ABOVE MENTIONED PACIFIC NORTHWEST SHORT-WAVE FORCES A STRONG
COLD FRONT SOUTH ACROSS SOUTH CENTRAL TEXAS LATE MONDAY NIGHT INTO
EARLY TUESDAY. THEN THE UPPER LEVEL TROUGH MOVES THROUGH LATER ON
TUESDAY. SOME LIGHT RAIN SHOWERS ARE POSSIBLE ACROSS EASTERN AREAS
WITH THE FRONT TUESDAY MORNING. THERE MAY BE A FEW SPRINKLES WITH
THE UPPER LEVEL TROUGH. HOWEVER...HAVE NOT MENTIONED AS THE LOWER
LEVELS WILL BE DRYING. A STRONG PRESSURE GRADIENT CREATES BREEZY
CONDITIONS WITH GUSTS UP TO 30 MPH TUESDAY. TEMPERATURES FALL BACK
TO BELOW AVERAGE FOR TUESDAY INTO WEDNESDAY. SOME LOW LYING SPOTS
IN THE HILL COUNTRY AND ALONG THE ESCARPMENT WILL DROP TO FREEZING
WEDNESDAY AND CHRISTMAS MORNINGS AS WINDS DECOUPLE SOMEWHAT AS
SURFACE HIGH MOVES ACROSS OUR AREA. THE HIGH MOVES OFF TO THE EAST
WITH SOUTHERLY LOWER FLOW WARMING TEMPERATURES BACK TO ABOVE
AVERAGE FOR CHRISTMAS AFTERNOON. ANOTHER STRONG COLD FRONT MOVES
ACROSS THE AREA FRIDAY LEADING TO BELOW AVERAGE TEMPERATURES FOR
NEXT WEEKEND. NO RAIN EXPECTED WITH THIS FRONT DUE TO LIMITED
MOISTURE. BEYOND THIS FORECAST PERIOD...SOME MODELS ARE SHOWING
EVEN COLDER AIR FOR NEXT WEEK IN THE DAYS BEFORE THE NEW YEAR.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              60  51  71  50  58 /  -   -   -   10  10
AUSTIN BERGSTROM INTL AIRPORT  60  48  71  49  59 /  -   -   -   10  10
NEW BRAUNFELS MUNI AIRPORT     61  50  73  51  60 /  -   -   -   10  10
BURNET MUNI AIRPORT            58  47  72  46  55 /  -   -   -   10  10
DEL RIO INTL AIRPORT           64  45  75  49  60 /  -   -    0  -   10
GEORGETOWN MUNI AIRPORT        59  49  71  48  56 /  -   -   -   10  10
HONDO MUNI AIRPORT             62  48  74  47  61 /  -   -    0  -   -
SAN MARCOS MUNI AIRPORT        61  49  71  50  59 /  -   -   -   10  10
LA GRANGE - FAYETTE REGIONAL   62  51  73  54  58 /  -   10  -   10  20
SAN ANTONIO INTL AIRPORT       61  51  73  50  61 /  -   -    0  10  10
STINSON MUNI AIRPORT           62  50  74  50  61 /  -   -    0  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE/AVIATION...29
SYNOPTIC/GRIDS...09
PUBLIC SERVICE/DATA COLLECTION...33









AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 303 PM CST SUN DEC 21 2014

.REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM
LEAD WAVE COMBINED WITH WAA GENERATING LIGHT PRECIP RETURNS ACROSS
WRN CWA. HOWEVER 88-D TRENDS SHOW COVERAGE DECREASING RAPIDLY WITH THIS.
SPOTTY LIGHT RAIN OR LIGHT SNOW WITH THIS BAND. MOIST FLOW CONTINUES
AHEAD OF ADVANCING LOW PRESSURE TROUGH IN THE PLAINS. SURFACE TEMPS
NOT EXPECTED TO DROP MUCH DUE TO SOUTHERLY WINDS AND CLOUD COVER. MID
LEVEL SHORTWAVE EXPECTED TO AMPLIFY AS IT DRAWS CLOSER. WEAKER SHORTWAVE
TO BRUSH SRN WI AFTER 6Z. WILL KEEP POPS CONFINED TO NW CWA CLOSER TO
850 LLJ AXIS AND AREA OF MODEL QPF. WITH MID LEVELS SHOWING A DRY LOOK
ON BUFKIT SOUNDINGS AND ANTICIPATED TEMPS REMAINING ABV ZERO NOT
EXPECTING ANY FREEZING RAIN/DRIZZLE.

.MONDAY - CONFIDENCE...MEDIUM
NEARLY STACKED LOW MOVERS INTO WESTERN IOWA. SHORTWAVE ENERGY WRAPPING
AROUND THIS UPPER LOW SHIFTS INTO SRN WI AND COINCIDES WITH INCREASING
850 MILLIBAR WIND MAX DURING THE AFTERNOON HOURS. MILD AIRMASS WITH HIGHS
IN THE U30S/L40S EXPECTED. NAM SOUNDING IN NW CWA LOOK A SMIDGE COLD
IN THE LOW LEVELS. PREFER THE BETTER HANDLING OF LOW LEVEL TEMP PROFILE
ON THE GFS SOUNDING. BUT PRECIP TYPE STILL QUESTIONABLE INTO THE AFTERNOON
ACROSS THE NW CWA. AREA SOUNDINGS SHOWING SN POTENTIAL WITH SATURATION IN THE
DENDRIDIC GROWTH ZONE. HOWEVER LOW LEVELS WILL DETERMINE EVENTUAL PRECIP
TYPE. SO WILL STILL KEEP MIXED PRECIP INTO THE AFTERNOON THERE WITH VRY LGT
ACCUMS. MUCH OF CWA EXPECTED TO BE RAIN IN THE AFTN THOUGH THE NW IS STILL
VULNERABLE WITH LOWEST 850 TEMPS AND COLDEST 1000-500 MILLIBAR THICKNESSES.

.MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE IS HIGH.

FAIRLY STRONG DYNAMICS ARRIVE MONDAY NIGHT AS THE MAIN CLOSED MID
LEVEL LOW SPINS OVER IOWA INTO SOUTHERN MN...EJECTING DECENT SHORT
WAVE ENERGY NORTHEAST INTO WISCONSIN. THE ASSOCIATED SURFACE LOW
WILL TRACK FROM NORTHWEST IOWA TO NORTH CENTRAL WISCONSIN BETWEEN
6 PM MONDAY THROUGH MID-DAY ON TUESDAY. DECENT WARM AIR ADVECTION
AHEAD OF THE LOW...RESULTING IN STRONG Q-VECTOR CONVERGENCE WHEN
COUPLED WITH THE MID LEVEL SHORT WAVE...SUPPORTS VERY HIGH POPS
INTO THE EVENING. TEMP PROFILES SUPPORT ALL RAIN WITH THE
POSSIBILITY OF A RAIN/SNOW MIX NORTHWEST OF MADISON.

WE SHOULD GET DRY SLOTTED LATER MONDAY NIGHT THROUGH TUESDAY WITH
LOW POPS MOVING IN. LIKELY JUST ANOTHER CLOUDY DAY WITH A SMALL
CHANCE OF RAIN OR SOME DRIZZLE AS THIS FIRST LOW MOVES OFF TO THE
NORTHEAST. TEMPS WILL BE MILD AS WE REMAIN ON THE WARM SIDE OF
THE LOW/TROF.

.TUESDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE
INCREASING.

IF YOU/VE BEEN FOLLOWING THE DISCUSSIONS...YOU KNOW THERE HAS BEEN
AN INCREDIBLE AMOUNT OF MODEL VARIABILITY IN THE HANDLING OF THE
SECONDARY LOW PRESSURE DEVELOPMENT COMING OUT OF THE LOWER
MISSISSIPPI VALLEY FOR THIS PERIOD. THE NEW 12Z RUNS ARE MUCH
TIGHTER AND THE LOWER SPREADS IN POSSIBLE SOLUTIONS PROVIDES
HIGHER CONFIDENCE. THE CONSENSUS LOW TRACK IS FROM THE OHIO VALLEY
NEAR LOUISVILLE TO SOUTHEAST LOWER MICHIGAN...THEN NORTHEAST FROM
THERE. THE SOUTHEAST WISCONSIN FORECAST AREA...INCLUDING THE
MILWAUKEE METRO AREA COULD GET INTO THE FAR WESTERN PRECIP SHIELD
AND GENERATE SOME LIGHT SNOW. BUT TEMPS WOULD PROBABLY STILL BE
WARM ENOUGH TO MELT MOST OF IT.

THE GFS/ECMWF/NAM/GEM KEEP THE HIGHEST IMPACT WEATHER WELL EAST
OF US. OF MINOR CONCERN IS A 12Z SUN PARALLEL HIGH RESOLUTION RUN
OF THE GFS THAT SHOWS A MAJOR LOW MOVING FROM ST. LOUIS TO
MILWAUKEE DURING THIS TIME. IT HAS BEEN ASSESSED AS A SIGNIFICANT
OUTLIER...NOT CLOSE TO ANY OTHER ENSEMBLE RUNS...AND IS BEING
DISCARDED. I MENTION IT AS THIS SOLUTION MAY MAKE IT/S WAY OUT
INTO THE SOCIAL MEDIA WORLD AND RAISE QUESTIONS. AND THE
CAVEAT...WE CAN/T LET OUR GUARD DOWN. THE TRACKS OF THESE LOWS CAN
CHANGE...SO REMAIN UP TO DATE ON THE LATEST FORECAST THROUGH
CHRISTMAS EVE.

.CHRISTMAS DAY...FORECAST CONFIDENCE IS HIGH.

FOR ALL THOSE PLANNING TO TRAVEL ON THE HOLIDAY...IT LOOKS LIKE A
DECENT DAY WITH DRY WEATHER AS HIGH PRESSURE BRIEFLY BUILDS IN.
TEMPS WILL BE IN THE LOWER TO MID 30S.

.FRIDAY...FORECAST CONFIDENCE IS MEDIUM.

LATE THURSDAY NIGHT AND FRIDAY...A FAST MOVING SHORT WAVE ARRIVES
IN THE ZONAL FLOW AND COULD BRING AROUND AN INCH OF SNOW. THE GFS
IS MUCH FARTHER NORTH WITH THE SFC LOW TRACK COMPARED TO THE
ECMWF AND THIS HAS BEEN THE CASE FOR THE LAST FEW RUNS. WPC IS
FAVORING THE ECMWF WHICH WILL SUPPORT A COLDER SOLUTION...WITH
THAT INCH OF SNOW POSSIBLE.

.SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

LOOKS LIKE HIGH PRESSURE RETURNS FOR NEXT WEEKEND. IT LOOKS DRY
WITH TEMPS RUNNING BELOW NORMAL...GENERALLY HIGHS IN THE LOWER TO
MID 20S.

&&

.AVIATION/00Z TAFS/...COMBO OF SHORTWAVE TROUGH MOVING EAST FROM WRN
MN AND WRN IA ALONG WITH SUSTAINED WAA...RESULTING IN MOST
WIDESPREAD PRECIP ACRS EC MN INTO NW WI. BAND OF MORE SCATTERED
PRECIP EXTENDS SOUTHWARD THROUGH SC WI. THIS WILL CONTINUE TO
TRANSLATE EWD THIS AFTN/ERLY EVE MOVING THROUGH THE REST OF SRN WI.
SFC TEMPS ABV FREEZING. RAP BUFKIT SOUNDINGS SHOW THE LOW LEVEL
SATURATION WITH DRY LAYER ABV AND HINTS OF MID LEVEL SATURATION
WITHIN DENDRIDIC GROWTH ZONE...SO CANNOT RULE OUT SOME SNOW...THOUGH
SEEDER FEEDER DRY DEPTH IS FAIRLY LARGE. IFR CIGS AND VSBYS WILL
PREVAIL WITH THE NAM MOS AND CONSSHORT HAVING THE BEST HANDLE ON
CIG/VSBY TRENDS. OVERALL MODELS KEEP MOST OF PRECIP THIS PERIOD
ACROSS WRN AND NRN WI WITH LESS IN THE SE. WITH LOW PRESSURE AND
MORE ORGANIZED SHORTWAVE APPROACHING MONDAY AFTERNOON/EVENING EXPECT
MORE WIDESPREAD RAINFALL MOVING INTO SRN WI. ANY MIXY POTENTIAL
LOOKS TO BE NORTH OR NORTHWEST OF TAF SITES.

&&

.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM PORT WASHINGTON
AND NWD AND STARTS AT 10 PM SOUTH OF PORT WASHINGTON. AS LOW
PRESSURE APPROACHES FROM THE NORTHERN PLAINS...BREEZY SOUTH TO
SOUTHEAST WINDS WILL CONTINUE TO RAMP UP INTO MONDAY NIGHT. THE
SOUTHERLY FETCH WILL GENERATE HIGH WAVES DURING THIS PERIOD. THE
WINDS AND WAVES WILL SUBSIDE ON TUESDAY AS THE WEAKENING LOW
PRESSURE AREA MOVES ACROSS THE REGION. THE SMALL CRAFT ADVISORY WILL
EXPIRE EARLY TUE AM.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM CST TUESDAY
     FOR LMZ644>646.

     SMALL CRAFT ADVISORY UNTIL 3 AM CST TUESDAY FOR LMZ643.

&&

$$

TONIGHT/MONDAY AND AVIATION/MARINE...COLLAR
MONDAY NIGHT THROUGH SUNDAY...DAVIS



AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 1104 AM CST SUN DEC 21 2014

.AVIATION/18Z TAFS/...COMBO OF SHORTWAVE TROUGH MOVING EAST FROM
WRN MN AND WRN IA ALONG WITH SUSTAINED WAA...RESULTING IN MOST
WIDESPREAD PRECIP ACRS EC MN INTO NW WI. BAND OF MORE SCATTERED
PRECIP EXTENDS SOUTHWARD THROUGH FAR WRN WI. THIS WILL CONTINUE
TO TRANSLATE EWD THIS AFTN MOVING THROUGH SRN WI. SFC TEMPS RISING
ABV FREEZING. RAP BUFKIT SOUNDINGS SHOW THE LOW LEVEL SATURATION
WITH DRY LAYER ABV AND HINTS OF MID LEVEL SATURATION WITHIN
DENDRIDIC GROWTH ZONE...SO CANNOT RULE OUT SOME SNOW...THOUGH
SEEDER FEEDER DRY DEPTH IS FAIRLY LARGE. IFR CIGS AND VSBYS WILL
PREVAIL WITH THE NAM MOS AND CONSSHORT HAVING THE BEST HANDLE ON
CIG/VSBY TRENDS. OVERALL MODELS KEEP MOST OF PRECIP THIS PERIOD
ACROSS WRN AND NRN WI WITH LESS IN THE SE. WITH LOW PRESSURE AND
MORE ORGANIZED SHORTWAVE APPROACHING MONDAY AFTERNOON/EVENING
EXPECT MORE WIDESPREAD RAINFALL MOVING INTO SRN WI. ANY MIXY
POTENTIAL LOOKS TO BE NORTH OR NORTHWEST OF TAF SITES.

PC

&&

.PREV DISCUSSION... /ISSUED 402 AM CST SUN DEC 21 2014/

SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.

AREAS OF VERY LIGHT FREEZING DRIZZLE AND A FEW SNOWFLAKES ARE
OVERSPREADING MUCH OF THE CWA FROM THE SW VIA LOW LEVEL WARM...MOIST
ADVECTION. SFC TEMPS TO WARM ABOVE FREEZING BY 16Z. DO NOT BELIEVE
THERE WILL BE ENOUGH OF AN IMPACT ON ROADWAYS FOR A FREEZING RAIN
ADVISORY AT THIS TIME. THE RESIDUAL CHEMICALS AND SALT ON ROADWAYS
FROM THE PAST SEVERAL DAYS MAY BE ENOUGH TO KEEP THE ROADS IN OKAY
CONDITION.

AS A WEAK SHORTWAVE TROUGH APPROACHES FROM THE PLAINS
TODAY AND PASSES TNT...THE 850 MB BAROCLINIC ZONE WILL SHIFT NEWD
ACROSS THE CWA THROUGHOUT THE DAY. FCST SOUNDINGS CONTINUE TO SHOW A
MID LEVEL DRY LAYER BUT STILL EXPECT THE LIFT TO RESULT IN SEEDER
FEEDER MECHANISM OR OUTRIGHT SATURATION IN SOME AREAS. THUS HAVE
CHANCE POPS FOR RAIN AND SNOW FROM LATE THIS MORNING THROUGH THE
AFTERNOON. THE CHANCES OF RAIN...SNOW...AND POSSIBLY FREEZING
DRIZZLE CONTINUE TNT WITH THE PASSAGE OF THE WEAK SHORTWAVE TROUGH
AND CONTINUED MOISTURE IN THE LOW LEVELS.


MONDAY-FORECAST CONFIDENCE HIGH

MODELS IN GOOD AGREEMENT IN STACKED AND FILLING LOW MOVING FROM
SOUTHEAST DAKOTA INTO IOWA.  THERE HAS BEEN A TREND FOR THERMAL
PROFILES AROUND 850MB TO BE COOLER WITH THIS SYSTEM...WITH 850 MB
TEMPS HOVERING AROUND 0C.  HOWEVER...JUST ENOUGH OF A LAPSE RATE IN
BOUNDARY LAYER WITH STALE COLD AIR AT SURFACE TO PERMIT TEMPERATURES
TO RISE WELL INTO THE 30S.  CERTAINLY COULD BE MIX OF RAIN AND WET
SNOW...BUT IMPACTS SHOULD BE MINIMAL WITH BULK OF PRECIPITATION
FALLING AS RAIN.

LOOKS LIKE AFTERNOON AND EVENING RUSH HOUR WILL BE WETTEST PERIOD.

LONG TERM...

TUESDAY AND WEDNESDAY-FORECAST CONFIDENCE LOW

NOT SURE HOW TO WORD THIS...BUT IT HAS BEEN A LONG TIME SINCE I HAVE
SEEN THIS MUCH UNCERTAINTY IN A DAY 3 FORECAST.  OPERATIONAL GFS AND
SREF HAVE TRENDED SLOWER AND SOUTH TOWARD LOWER MISSISSIPPI RIVER
VALLEY WITH 2ND LOW PRESSURE WAVE...WHILE ECMWF AND PARALLEL GFS
FOCUS ON MORE NORTHERN SOLUTION NEAR THE GREAT LAKES.

AT FIRST GLANCE THE GEFS AND SREF SOLUTIONS SHOW POTENTIAL FOR A
DREADED GULF LOW TRACK WITH HEAVY WET SNOW POTENTIAL.
HOWEVER...WITH TREND OF OTHER RELIABLE MODELS LIKE ECMWF TOWARD
ABSENCE OF DEEP LOW OVER GREAT LAKES...SEE POTENTIAL FOR VERY LITTLE
PRECIPITATION OR SNOW BEING GREATER OVER SOUTHERN WISCONSIN THAN
POTENTIAL FOR SIGNIFICANT STORM.

RIGHT NOW A CONSERVATIVE CONSENSUS FORECAST IS THE ONLY VIABLE
OPTION I SEE.  IT LOOKS LIKE GRADUAL COOLING OF THE COLUMN WITH
CHANCE OF RAIN GOING TO SNOW WITH LARGE RANGE OF POSSIBLE
PRECIPITATION AMOUNTS...BUT LEANING TOWARD DRIER SOLUTIONS.

THURSDAY THROUGH SATURDAY-FORECAST CONFIDENCE MEDIUM

GFS AND ECMWF ARE IN BETTER AGREEMENT ON FAST MOVING LOW COMING OUT
OF KANSAS AHEAD OF A POLAR SURGE AND THEN HEADING FOR THE GREAT
LAKES. A FRONTOGENETIC SNOW BAND IS SHOWN TO PUSH FROM NEBRASKA TO
IOWA AND WISCONSIN THURSDAY INTO EARLY FRIDAY.

THIS BAND WOULD BE RATHER NARROW...SO MIGHT ONLY AFFECT 2-3 COUNTY
WIDE AREA AND COULD EASILY MISS MOST AREAS.  BEST GUESS RIGHT NOW IS
LIGHT AMOUNTS ESPECIALLY IN NORTHERN HALF OF AREA.

AVIATION/12Z TAFS/...CIGS WILL RANGE FROM JUST A FEW HUNDRED FEET
OR LESS OVER SOUTH CENTRAL WI TO A 1000 FEET IN THE EAST TODAY AS
AREAS OF FREEZING DRIZZLE...RAIN...SNOW MOVE ACROSS THE AREA. SFC
TEMPS TO WARM ABOVE FREEZING BY 10 AM...ENDING THE ICING
THREAT...BUT A LIGHT COATING OF ICE ON SURFACES WILL OCCUR
BEFOREHAND. THE CIGS WILL LIFT TO 1-3 KFT FOR TNT. VSBYS OF 3-5SM
WILL PREVAIL WEST OF THE MILWAUKEE METRO AREA FOR MOST OF SUN AND
SUN NT. RAIN...SNOW...AND PATCHY FREEZING DRIZZLE WILL REMAIN IN THE
FORECAST FOR TNT.

MARINE...A SMALL CRAFT ADVISORY GOES INTO EFFECT LATER THIS
AFTERNOON FROM PORT WASHINGTON AND NWD AND STARTS AT 10 PM SOUTH OF
PORT WASHINGTON. AS LOW PRESSURE APPROACHES FROM THE NORTHERN
PLAINS...BREEZY SOUTH TO SOUTHEAST WINDS WILL DEVELOP LATER TODAY
INTO MONDAY NIGHT. THE SOUTHERLY FETCH WILL GENERATE HIGH WAVES
DURING THIS PERIOD. THE WINDS AND WAVES WILL SUBSIDE ON TUESDAY AS
THE WEAKENING LOW PRESSURE AREA MOVES ACROSS THE REGION. THE SMALL
CRAFT ADVISORY WILL EXPIRE EARLY TUE AM.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM CST TUESDAY
     FOR LMZ644>646.

     SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
     TUESDAY FOR LMZ643.

&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...CRAVEN