Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/22/15

AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 518 AM MST SUN DEC 20 2015

.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS...

&&

.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL BRING SLIGHTLY COOLER CONDITIONS TO THE
AREA TODAY. THERE IS ALSO A SLIGHT CHANCE OF SHOWERS ACROSS NORTHERN
MARICOPA AND GILA COUNTIES. PACIFIC MOISTURE WILL SPREAD ACROSS THE
REGION THROUGH THE WEEK RESULTING IN PERIODS OF CLOUDINESS AND A
SLIGHT CHANCE OF PRECIPITATION...MAINLY NORTH AND EAST OF PHOENIX.
TEMPERATURES WILL REMAIN NEAR NORMAL BUT ARE EXPECTED TO DROP LATE
IN THE WEEK AND INTO THE WEEKEND AS A LOW PRESSURE SYSTEM AFFECTS THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
WV IMAGERY SHOWS A WELL-DEFINED VORT MAX MOVING STEADILY EASTWARD
THROUGH THE MOJAVE DESERT. AT THE SURFACE...A WEAK COLD FRONT EXTENDS
FROM AN AREA OF LOW PRESSURE ACROSS THE SOUTHERN ROCKIES INTO THE
LOWER CO RIVER VALLEY. A FEW SHOWERS ALONG THE FRONT HAVE BEEN
OBSERVED NEAR EL CENTRO...WHICH AMOUNTED TO A TRACE. LATEST HRRR SUGGESTS
THIS LINE WILL WEAKEN AS IT HEADS EAST INTO AZ...THOUGH RUNS OF THE
LOCAL WRF SUGGEST SOME REDEVELOPMENT OF ISOLATED SHOWERS ACROSS THE
HIGHER TERRAIN OF MARICOPA AND GILA COUNTIES LATER THIS MORNING.
OTHERWISE...TEMPERATURES WILL BE A FEW DEGREES COOLER TODAY BEHIND
THE TROUGH...WITH HIGHS GENERALLY IN THE LOWER 60S ACROSS THE LOWER
DESERTS.

MODELS REMAIN IN GOOD AGREEMENT EARLY THIS WEEK...INDICATING A
STRONG ATMOSPHERIC RIVER WILL DEVELOP AROUND AN ANTICYCLONE IN THE
CENTRAL PACIFIC. RESULTING NORTHWESTERLY FLOW WILL RESULT IN PERIODS
OF MID AND HIGH CLOUDS ALONG WITH A GRADUAL WARMING TREND THROUGH
THURSDAY. BRUNT OF THE PRECIPITATION WILL BE WELL TO OUR
NORTH...ALONG THE WEST COAST AND ACROSS THE INTERMOUNTAIN WEST.
HOWEVER...LATEST OPERATIONAL GFS/ECMWF SUGGEST THAT SUFFICIENT
MOISTURE TRANSPORT WILL COINCIDE WITH OCCASIONAL ASCENT TO SUPPORT
ISOLATED SHOWER ACTIVITY ACROSS THE HIGHER TERRAIN...MAINLY NORTHEAST
OF PHOENIX THROUGH THURSDAY. IT IS DIFFICULT TO PINPOINT EXACTLY WHEN
THE BEST CHANCE OF PRECIPITATION WILL OCCUR...THOUGH THE MODEL
CONSENSUS IS THAT ANY RAIN THAT DOES DEVELOP WILL BE QUITE LIGHT.

MODELS ARE EXHIBITING CONSIDERABLE MORE SPREAD WITH REGARD TO THE
EVOLUTION OF A TROUGH LATE IN THE WEEK. THE TROUGH IS EXPECTED TO
DROP SOUTHWARD OUT OF THE GULF OF ALASKA AND TOWARDS THE DESERT
SOUTHWEST. HOWEVER...RECENT TRENDS IN THE NAEFS...GEFS AND ECMWF
ENSEMBLE MEANS SUGGEST LESS OF AN IMPACT ACROSS THE AREA. ALL
ENSEMBLE MEANS ALONG WITH THE OPERATIONAL ECMWF DEPICT AN OPEN WAVE
PASSING BY TO OUR NORTH AND EAST. LATEST 00Z OPERATIONAL GFS IS
CONSIDERABLY STRONGER AND FURTHER WEST...THOUGH IT APPEARS TO BE AN
OUTLIER WHEN COMPARED TO ITS ENSEMBLES. NORMALIZED SPREAD AMONG THE
ECMWF ENSEMBLE MEMBERS IS ALIGNED WITH THE TROUGH AXIS...SUGGESTING
THAT THE UNCERTAINTY IS MORE WITH MAGNITUDE OF THE SYSTEM AND LESS
WITH THE POSITIONING AND TIMING. FORECAST POPS HAVE BEEN LOWERED
SOMEWHAT FOR CHRISTMAS DAY THROUGH SATURDAY. HOWEVER...A SLIGHT
CHANCE REMAINS...OWING TO THE PREPONDERANCE OF PREVIOUS RUNS THAT
SUGGESTED A DEEPER AND LESS PROGRESSIVE SYSTEM.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

UPPER LEVEL TROUGH QUICKLY MOVING THROUGH ARIZONA THIS MORNING WILL
BRING ISOLATED LIGHT RAIN SHOWERS TO HIGHER TERRAIN AREAS NORTH AND
EAST OF PHOENIX THROUGH 18Z. A CLOUD BAND WITH BKN DECKS DOWN TO 6K
FEET AT TIME SHOULD ALSO AFFECT THE PHOENIX AREA THROUGH MID MORNING
BEFORE BECOMING MORE SCATTERED IN NATURE THROUGH THE REST OF THE
AFTERNOON HOURS. EVENTUALLY CLOUDS WILL LIFT WITH JUST HIGH CLOUDS
REMAINING FOR THE REST OF TONIGHT. WINDS ACROSS THE PHOENIX AREA WILL
REMAIN LESS THAN 10 KTS AND GENERALLY FOLLOW TYPICAL DIURNAL
DIRECTIONAL PATTERNS WHILE INITIAL BREEZY CONDITIONS ACROSS SOUTHEAST
CALIFORNIA WILL TURN TO LIGHTER WINDS STARTING THIS AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
DRY NORTHWEST FLOW ALOFT WILL DOMINATE INTO THE MIDDLE PART OF THE WEEK
BEFORE INCREASING MOISTURE SLOWLY BEGINS TO AFFECT THE REGION. THIS
MOISTURE WILL EVENTUALLY ALLOW FOR RAIN/SNOW CHANCES BEGINNING
WEDNESDAY OR THURSDAY WITH A STRONG PACIFIC LOW PRESSURE TROUGH
AIDING IN BETTER PRECIPITATION CHANCES ON THURSDAY AND FRIDAY.
TEMPERATURES WILL START OUT NEAR NORMALS...BUT WITH THE TROUGH
DIGGING IN LATE NEXT WEEK TEMPERATURES WILL DIP TO WELL BELOW NORMAL
READINGS STARTING FRIDAY. WINDS THROUGH WEDNESDAY WILL REMAIN ON THE
LIGHT SIDE WITH SOME BREEZY TO GUSTY WINDS AT TIMES ON THURSDAY AND
FRIDAY. POTENTIAL FOR STRONG WINDS WITH GUSTS APPROACHING 40 MPH ARE
POSSIBLE ON SATURDAY...MAINLY AFFECTING THE LOWER COLORADO RIVER
VALLEY. MINIMUM RELATIVE HUMIDITIES WILL BE ON THE HIGHER SIDE
THROUGH MUCH OF THE PERIOD MOSTLY FALLING IN A 25-40 PERCENT
RANGE...BUT DRIER AIR WORKING FROM THE NORTHWEST FRIDAY NIGHT AND
SATURDAY WILL ALLOW FOR HUMIDITIES TO DROP INTO THE TEENS.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN



AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 338 AM MST SUN DEC 20 2015

.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL BRING SLIGHTLY COOLER CONDITIONS TO THE
AREA TODAY. THERE IS ALSO A SLIGHT CHANCE OF SHOWERS ACROSS NORTHERN
MARICOPA AND GILA COUNTIES. PACIFIC MOISTURE WILL SPREAD ACROSS THE
REGION THROUGH THE WEEK RESULTING IN PERIODS OF CLOUDINESS AND A
SLIGHT CHANCE OF PRECIPITATION...MAINLY NORTH AND EAST OF PHOENIX.
TEMPERATURES WILL REMAIN NEAR NORMAL BUT ARE EXPECTED TO DROP LATE
IN THE WEEK AND INTO THE WEEKEND AS A LOW PRESSURE SYSTEM AFFECTS THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
WV IMAGERY SHOWS A WELL-DEFINED VORT MAX MOVING STEADILY EASTWARD
THROUGH THE MOJAVE DESERT. AT THE SURFACE...A WEAK COLD FRONT EXTENDS
FROM AN AREA OF LOW PRESSURE ACROSS THE SOUTHERN ROCKIES INTO THE
LOWER CO RIVER VALLEY. A FEW SHOWERS ALONG THE FRONT HAVE BEEN
OBSERVED NEAR EL CENTRO...WHICH AMOUNTED TO A TRACE. LATEST HRRR SUGGESTS
THIS LINE WILL WEAKEN AS IT HEADS EAST INTO AZ...THOUGH RUNS OF THE
LOCAL WRF SUGGEST SOME REDEVELOPMENT OF ISOLATED SHOWERS ACROSS THE
HIGHER TERRAIN OF MARICOPA AND GILA COUNTIES LATER THIS MORNING.
OTHERWISE...TEMPERATURES WILL BE A FEW DEGREES COOLER TODAY BEHIND
THE TROUGH...WITH HIGHS GENERALLY IN THE LOWER 60S ACROSS THE LOWER
DESERTS.

MODELS REMAIN IN GOOD AGREEMENT EARLY THIS WEEK...INDICATING A
STRONG ATMOSPHERIC RIVER WILL DEVELOP AROUND AN ANTICYCLONE IN THE
CENTRAL PACIFIC. RESULTING NORTHWESTERLY FLOW WILL RESULT IN PERIODS
OF MID AND HIGH CLOUDS ALONG WITH A GRADUAL WARMING TREND THROUGH
THURSDAY. BRUNT OF THE PRECIPITATION WILL BE WELL TO OUR
NORTH...ALONG THE WEST COAST AND ACROSS THE INTERMOUNTAIN WEST.
HOWEVER...LATEST OPERATIONAL GFS/ECMWF SUGGEST THAT SUFFICIENT
MOISTURE TRANSPORT WILL COINCIDE WITH OCCASIONAL ASCENT TO SUPPORT
ISOLATED SHOWER ACTIVITY ACROSS THE HIGHER TERRAIN...MAINLY NORTHEAST
OF PHOENIX THROUGH THURSDAY. IT IS DIFFICULT TO PINPOINT EXACTLY WHEN
THE BEST CHANCE OF PRECIPITATION WILL OCCUR...THOUGH THE MODEL
CONSENSUS IS THAT ANY RAIN THAT DOES DEVELOP WILL BE QUITE LIGHT.

MODELS ARE EXHIBITING CONSIDERABLE MORE SPREAD WITH REGARD TO THE
EVOLUTION OF A TROUGH LATE IN THE WEEK. THE TROUGH IS EXPECTED TO
DROP SOUTHWARD OUT OF THE GULF OF ALASKA AND TOWARDS THE DESERT
SOUTHWEST. HOWEVER...RECENT TRENDS IN THE NAEFS...GEFS AND ECMWF
ENSEMBLE MEANS SUGGEST LESS OF AN IMPACT ACROSS THE AREA. ALL
ENSEMBLE MEANS ALONG WITH THE OPERATIONAL ECMWF DEPICT AN OPEN WAVE
PASSING BY TO OUR NORTH AND EAST. LATEST 00Z OPERATIONAL GFS IS
CONSIDERABLY STRONGER AND FURTHER WEST...THOUGH IT APPEARS TO BE AN
OUTLIER WHEN COMPARED TO ITS ENSEMBLES. NORMALIZED SPREAD AMONG THE
ECMWF ENSEMBLE MEMBERS IS ALIGNED WITH THE TROUGH AXIS...SUGGESTING
THAT THE UNCERTAINTY IS MORE WITH MAGNITUDE OF THE SYSTEM AND LESS
WITH THE POSITIONING AND TIMING. FORECAST POPS HAVE BEEN LOWERED
SOMEWHAT FOR CHRISTMAS DAY THROUGH SATURDAY. HOWEVER...A SLIGHT
CHANCE REMAINS...OWING TO THE PREPONDERANCE OF PREVIOUS RUNS THAT
SUGGESTED A DEEPER AND LESS PROGRESSIVE SYSTEM.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

CLOUD BAND ASSOCIATED WITH APPROACHING COLD FRONT AS OF 04Z EXTENDS
FROM NORTHEAST NEVADA SOUTH-SOUTHWESTWARD TO NEAR KSAN. ANTICIPATE
SOME BREAKUP OF THE CLOUD BAND AS IT MOVES OVER THE SOUTHERN
CALIFORNIA MOUNTAINS INTO THE DESERTS TONIGHT. HOWEVER...EXPECT AT
LEAST SOME SCATTERED CUMULUS AT FL050-070 REACHING LOWER COLORADO
RIVER VALLEY BY 07Z-09Z AND PHOENIX AREA BY 10Z-12Z. ANTICIPATE A
GOOD POSSIBILITY OF THE CUMULUS BEING BKN-OVC AT TIMES EAST OF THE
LOWER COLORADO RIVER VALLEY...INCLUDING METRO PHOENIX. SOME SPOTTY
LIGHT SHOWERS/SPRINKLES ARE ALSO POSSIBLE. EXPECT SOUTHWEST AND WEST
SURFACE WINDS NEAR AND EAST OF THE LOWER COLORADO RIVER VALLEY TO
CONTINUE OVERNIGHT AND WELL INTO THE DAY SUNDAY. OVER PHOENIX
AREA...SURFACE WINDS WILL REMAIN LIGHT AND FAVOR THE SOUTHEAST
QUADRANT THROUGH AT LEAST 15Z BEFORE TRENDING TO SOUTHWEST BY 17-19Z.
STRONG SOUTHWEST AND WEST WINDS ALOFT CAN BE EXPECTED OVERNIGHT AND
THROUGH THE DAY SUNDAY. ANTICIPATE THAT WE WILL REMAIN BELOW LLWS
CRITERIA THOUGH.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
DRY NORTHWEST FLOW ALOFT WILL DOMINATE THROUGH THE MIDDLE OF NEXT
WEEK BEFORE A STRONG PACIFIC LOW PRESSURE TROUGH APPROACHES THE
REGION FOR LATE IN THE WEEK. THIS TROUGH WILL BRING INCREASING
MOISTURE AND A CHANCE OF PRECIPITATION STARTING THURSDAY. BEST
CHANCES FOR WETTING RAIN/SNOW WILL LIKELY FALL ON FRIDAY.
TEMPERATURES WILL END UP AROUND NORMAL READINGS THROUGH THURSDAY BUT
WITH THE TROUGH DIGGING IN LATE NEXT WEEK TEMPERATURES WILL DIP TO
WELL BELOW NORMAL READINGS FOR FRIDAY. WINDS THROUGH WEDNESDAY WILL
REMAIN ON THE LIGHT SIDE WITH SOME BREEZY TO GUSTY WINDS AT TIMES ON
THURSDAY AND FRIDAY. MINIMUM RELATIVE HUMIDITIES WILL BE ON THE
HIGHER SIDE AND MOSTLY FALL IN A 25-40 PERCENT RANGE.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...AJ
FIRE WEATHER...KUHLMAN




AREA FORECAST DISCUSSION

NWS DENVER/BOULDER CO

 313 PM MST SUN DEC 20 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 126 PM MST SUN DEC 20 2015

UPPER TROF OVER WRN CO THIS AFTN WILL MAKE ITS WAY TO THE ERN
CO BY 00Z WITH A WNWLY FLOW ALOFT OVERNIGHT. BEST QG ASCENT TODAY
WILL THIS AFTN...WITH INCREASING QG DESCENT OVERNIGHT. IN THE
MOUNTAINS TONIGHT...INCREASING STABILITY AND SUBSIDENCE WILL
DEVELOP OVERNIGHT...BUT A GOOD OROGRAPHIC/MOISTURE COMPONENT
PRESENT THIS EVENING...THEN LATE TNGT AND MONDAY MORNING...THE
NAM12 SPATIAL CROSS SECTIONS SHOWS MOISTURE DEPTH DECREASING
SIGNIFICANTLY. SNOWFALL AT THAT TIME WILL BE MINIMAL AND CONFINED
PRIMARILY TO WEST FACING SLOPES. WINDY AS WELL...BUT THE MOUNTAIN
WAVE IS NOT VERY AMPLIFIED SO STRONGER GUSTS SHOULD BE ABOVE
TIMBERLINE OR HIGH EXPOSED EAST FACING SLOPES. FOR THE NORTHEAST
PLAINS...THE HRRR CONTINUES TO GENERATE PCPN AROUND THE URBAN
CORRIDOR AND PALMER DIVIDE LATE THIS AFTN AND EVENING...WL KEEP
ISOLD-CHC POPS PRIMARILY EAST AND SOUTH OF DENVER THROUGH 02Z OR
SO. ON MONDAY...SHORT WAVE RIDGE WITH GOOD MID LEVEL SUBSIDENCE
THROUGH 18Z. SNOW DOES RETURN TO THE HIGH COUNTRY BY LATE AFTN AS
THE RIDGE SHIFTS EAST AND WEAK QG ASCENT DEVELOPS AHEAD OF THE
NEXT SYSTEM. SNOWFALL WILL REMAIN ON THE LIGHT SIDE...AN INCH OR
LESS. IN DENVER AND THE NORTHEAST PLAINS DRY MONDAY WITH
TEMPERATURES NEAR SEASONAL NORMALS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 126 PM MST SUN DEC 20 2015

MODELS HAVE MODERATE WESTERLY FLOW ALOFT FOR THE CWA MONDAY
NIGHT. ON TUESDAY A BIT OF AN UPPER TROUGH AXIS PUSHES ACROSS
COLORADO PART OF A BROAD MEAN TROUGH DEVELOPING OVER A GOOD PART
OF NORTH AMERICA. THIS FEATURE MOVES LITTLE SLIGHT EASTWARD AND
THROUGH WEDNESDAY NIGHT. BY WEDNESDAY NIGHT...THE WESTERLY FLOW
ALOFT OVER US IS QUITE STRONG WITH A 140 KNOW JET MAXIMUM GETTING
INTO SOUTHWEST COLORADO BY 12Z THURSDAY MORNING. THE QG VERTICAL
VELOCITY FIELDS SHOW WEAK UPWARD SYNOPTIC SCALE ENERGY MONDAY
NIGHT AND TUESDAY...THEN WEAK DOWNWARD ENERGY INTO WEDNESDAY.
THERE IS A BIT OF UPWARD AGAIN WEDNESDAY AFTERNOON...THEN
DOWNWARD WEDNESDAY NIGHT. THE LOW LEVEL WINDS ARE NORMAL DRAINAGE
PATTERNS MONDAY NIGHT. TUESDAY`S WINDS LOOK TO BE NORMAL DIURNAL
PATTERNS TOO. TUESDAY NIGHT HAS SOME NORTHWESTERLY DOWNSLOPING.
WEDNESDAY HAS VARIABLE DIRECTIONS DEPENDING ON THE MODEL. THEY ARE
ALL OVER THE PLACE AND NOT VERY STRONG...SO NORMAL PATTERNS LOOK
GOOD. DOWNSLOPING TO DRAINAGE WEDNESDAY NIGHT. FOR MOISTURE...
THERE IS PLENTY OVER THE MOUNTAINS WEST OF THE DIVIDE AND RIGHT
ALONG IT MUCH OF THE TIME...AT LEAST THROUGH 06Z TUESDAY NIGHT.
MOISTURE DECREASES INTO WEDNESDAY MORNING...THEN INCREASES AGAIN
IN THE MOUNTAINS BY AFTERNOON INTO WEDNESDAY EVENING. MOISTURE
DECREASES AGAIN LATE WEDNESDAY NIGHT. THE QPF FIELDS DO SHOW
MEASURABLE SNOWFALL...MAINLY IN THE MOUNTAINS. THE HIGHEST AMOUNTS
OCCUR ON TUESDAY INTO TUESDAY EVENING...BUT THEY ARE STILL NOT
SIGNIFICANT. CONCERNING HIGHLIGHT FOR MOUNTAIN SNOWS...THE RHEA-
THALER SNOW MODEL DOES NOT YIELD WARNING AMOUNTS IN MOST AREAS.
THE EXCEPTION MAY BE ZONE 31. THERE ARE 9-15 INCHES IN ZONES 31
FROM 00Z MONDAY EVENING THROUGH 12Z WEDNESDAY MORNING. THERE ARE
SOME DYNAMICS...BUT NOTHING GREAT. ALSO 700 MB WINDS SPEEDS ARE
NOT THAT STRONG AND DIRECTION IS NOTE EVEN DUE WESTERLY. THE
DECENT SNOWFALL RATES DO NOT APPEAR TO KICK IN UNTIL 12Z TUESDAY
MORNING AS WELL...SO NO HIGHLIGHTS YET. FOR TEMPERATURES...TUESDAY`S
HIGHS ARE 0-2 C WARMER THAN MONDAY`S. WEDNESDAY`S HIGHS ARE 1-3 C
COOLER THAN TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH
SUNDAY...THERE IS A BROAD UPPER TROUGH OVER COLORADO THURSDAY
...WITH A STRONG WEST-SOUTHWESTERLY JET MAXIMUM ACROSS THE STATE.
THE UPPER TROUGH DEEPENS TO OUT WEST OVER THE GREAT BASIN ON
FRIDAY...WITH STRONG SOUTHWESTERLY FLOW ALOFT FOR THE CWA. THE
UPPER TROUGH DEEPENS FRIDAY NIGHT AND SATURDAY AND MOVES
EASTWARD. THE AXIS IS OVER THE CWA AT 00Z EARLY SATURDAY EVENING.
NORTHERLY FLOW ALOFT IS OVER THE CWA SATURDAY NIGHT...THAN
NORTHWESTERLY ON SUNDAY. THE ONLY NOTABLE COLD FRONT IS FOR
FRIDAY AFTERNOON ALONG WITH SOME UPSLOPE OVER THE PLAINS THROUGH
SATURDAY. WILL NEED "CHANCE"S OF SNOW 1IN THE MOUNTAINS MUCH OF
THE TIME INTO SATURDAY...THEN NOTHING THROUGH SUNDAY. FOR THE
PLAINS...WILL GO WITH A "SLIGHT CHANCE"S OF SNOW THURSDAY EVENING
THROUGH SATURDAY. THE BEST SHOT NOW LOOKS TO BE FRIDAY NIGHT...BUT
THAT WILL LIKELY CHANGE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 126 PM MST SUN DEC 20 2015

UPPER TROUGH WILL PASS TO THE EAST BY EARLY THIS EVENING. UNTIL
THAT TIME...SUFFICIENT MOISTURE AND MID LEVEL INSTABILITY TO
SUPPORT A FEW BRIEF RAIN/SNOW SHOWERS. COULD SEE CIGS BKN CIGS OF
6-7 KFT AGL WITH ANY SHOWERS. IMPROVING CIGS AFTER 01Z...WITH VFR
CONDITIONS THE REST OF THE PERIOD. E/NELY WINDS WILL TRANSITION
TO S/SELY THIS EVENING THEN SWLY BY 03Z. WINDS PRIMARILY SWLY ON
MONDAY.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...COOP
LONG TERM...KOOP
AVIATION...COOP




AREA FORECAST DISCUSSION

NWS DENVER/BOULDER CO

 845 AM MST SUN DEC 20 2015

.UPDATE...
ISSUED AT 825 AM MST SUN DEC 20 2015

LATEST HRRR SHOWING GREATER AREAS COVERAGE FOR PCPN/QPF THIS AFTN
ACROSS THE NORTHEAST PLAINS. AS A RESULT...A INCREASED THE MENTION
OF SLIGHT CHANCE 10-20 PERCENT COVERAGE...GENERALLY FM AROUND
DENVER/BOULDER EAST AND SOUTH AFTER 20Z. RUC13 SOUNDINGS SHOW
DECENT MOISTURE TO GO WITH SOME FVBL INSTBY WITH THE PASSAGE OF
THE TROUGH THIS AFTN...SO DOWNSLOPE/DCRG QG ASCENT MAY REDUCE THE
POPS ACROSS THE FOOTHILLS AND ADJACENT PLAINS BUT WILL NOT NEGATE
IT ALTOGETHER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM MST SUN DEC 20 2015

WATER VAPOR IMAGERY SHOWING ELONGATED TROF MOVING EAST OVER GREAT
BASIN EARLY THIS AM WITH A CIRCULATION CENTER OVER FAR SOUTHERN
NEVADA. THIS TROF WILL MOVE ACROSS COLORADO DURING THIS AFTERNOON.
THERE IS STILL A FAIR AMOUNT OF MID AND HIGH LEVEL MOISTURE AHEAD
OF THIS FEATURE WITH MOST OF THE BETTER MOISTURE ASSOCIATED WITH
THE LOW OVER SOUTHERN NEVADA AND WESTERN UTAH. THIS BETTER
MOISTURE WILL MOVE INTO THE MOUNTAINS THIS AFTERNOON. OVERALL THIS
SYSTEM NOT LOOKING VERY IMPRESSIVE BUT THERE IS MODEST AMOUNTS OF
QG UPWARD FORCING THIS AFTERNOON. OVERALL MOISTURE DOES APPEAR TO
BE LACKING WITH THIS SYSTEM DESPITE DECENT QG NUMBERS. LAPSE RATES
DO STEEPEN LATER IN THE DAY WHICH WILL HELP SOME IN PRECIP
POTENTIAL. OVERALL SNOWFALL IN THE MOUNTAINS LOOKS TO BE LIGHT
WITH GENERALLY 1-3 INCH ACCUMULATION AS OROGRAPHIC FLOW IMPROVES
DURING THE AFTERNOON. FOR TONIGHT IN THE MOUNTAINS...MOISTURE
BECOMES MORE SHALLOW WHILE WARM ADVECTION DEVELOPS AT MOUNTAIN
TOP. STILL GOOD OROGRAPHIC FLOW DESPITE LAPSE RATES SO COULD STILL
SEE A FEW MORE INCHES OF SNOW IN THE MOUNTAINS. GUSTY WINDS AT
TIMES AS WELL WITH THE STRONG WESTERLY FLOW. DOSEN`T LOOK LIKE
HIGH WINDS BUT CERTAINLY SOME GUSTS IN THE 30-50 MPH RANGE.

ACROSS NORTHEAST COLORADO A WEAK ASSOCIATED COLD FRONT WILL MOVE
SOUTHWARD LATER THIS MORNING AS WINDS SHIFT NORTHERLY. MODELS ARE
HINTING AT SOME LIGHT SHOWERS DEVELOPING OVER THE PALMER DIVIDE
AND FAR EASTERN PLAINS SO WILL ADD SOME LOW POPS IN THOSE AREAS.
TEMPERATURES WILL BE A BIT COOLER ON THE PLAINS FOLLOWING THE
FRONTAL PASSAGE.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM MST SUN DEC 20 2015

A SHORTWAVE TROUGH WILL PASS OVER THE AREA MONDAY MORNING FOR AN
INCREASE IN SNOWFALL OVER THE MOUNTAINS. STRONG AND GUSTY WINDS
 TO 50 MPH WILL CAUSE VISIBILITY ISSUES ALONG THE HIGHER PASSES
IN BLOWING SNOW. SLIGHT RIDGING WILL SLOW SNOWFALL THROUGH THE
REST OF THE DAY AND EVENING. IT WILL REMAIN DRY OVER THE PLAINS
WITH SLIGHTLY COOLER TEMPERATURES FROM THE PASSING SHORTWAVE.

LATE MONDAY NIGHT INTO TUESDAY...A STRONG PACIFIC JET ORIENTED ALONG
THE NORTHWEST FLOW WILL PUSH INTO THE GREAT BASIN PUSHING MORE
MOISTURE INTO THE COLORADO MOUNTAINS. THE JET WILL MOVE OVER THE
STATE TUESDAY AND WEDNESDAY BEFORE TURNING MORE WESTERLY THEN
SOUTHWESTERLY ACROSS THE SOUTHERN PART OF THE STATE THROUGH THE
REST OF THE WEEK. THIS WILL BRING AN EXTENDED PERIOD OF SNOW
ACROSS THE MOUNTAINS. OROGRAPHIC SNOW IS EXPECTED TO RAMP UP
ESPECIALLY AFTER MIDNIGHT....WITH 2 TO 5 INCHES FALLING BY TUESDAY
MORNING. WINDS WILL BE INCREASING AS WELL AS A SURFACE LOW DEEPENS
OVER THE LEE OF THE ROCKIES. SNOW IS EXPECTED TO CONTINUE FALLING
OVER THE MOUNTAINS THROUGH WEDNESDAY EVENING AT LEAST. WITH THE
EXTENDED TIME OF SNOWFALL AND WINDS...A HIGHLIGHT MAY NEED TO BE
ISSUED TO DEAL WITH THE IMPACTS ON TRAVEL AND SAFETY. THE PLAINS
MAY SEE A SNOW SHOWER OR TWO MOVE EAST FROM THE FOOTHILLS TUESDAY
NIGHT AS AS UPPER TROUGH PASSES OVERHEAD.

A LONGWAVE UPPER TROUGH WILL DIG OVER THE GREAT BASIN THURSDAY.
MODELS ARE HAVING A HARD TIME COMING TO A CONSENSUS ON WHAT THE
FEATURE WILL END UP DOING AFTER THIS. THE FEATURE MAY EITHER DIG
SOUTH INTO NORTHERN MEXICO AS A CUTOFF LOW BY SATURDAY LIKE THE GFS
SHOWS...OR PASS OVER THE STATE FRIDAY THEN BECOME A CLOSED LOW OVER
KANSAS BY SATURDAY MORNING BEFORE PUSHING NORTHEAST INTO THE GREAT
LAKES REGION BY SUNDAY. EITHER WAY...BOTH MODELS HINTING AT PRECIP
PUSHING NORTH INTO THE STATE THURSDAY EVENING THEN EITHER HEADING
BACK SOUTH LIKE THE GFS SHOWS OR PUSHING EAST INTO A NICE GREAT
PLAINS STORM LIKE THE ECMWF. WILL HAVE A SLIGHT CHANCE OF SNOW FOR
THE PLAINS FOR CHRISTMAS EVE AND CHRISTMAS DAY.

THE WEEKEND LOOKS TO DRY AND WARM UP AS UPPER RIDGING PUSHES OVER
THE STATE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 825 AM MST SUN DEC 20 2015

CONSIDERABLE MID-HIGH LEVEL MOISTURE AHEAD OF WEAK TROF THIS
MORNING. AS THE TROF MOVES ACROSS THE AREA DURING THE AFTERNOON
COULD BE ISOLATED RAIN/SNOW SHOWERS SO HAVE ADDED VCSH TO THE
TAFS. MAY LOWER THE CIGS A BIT MORE AS WELL TO A TEMPO BKN CIGS OF
5-6KFT AGL AFTER 21Z AS WELL IN THE UPCOMING TAFS. E/NE SFC WINDS
AT DIA AT THIS TIME WILL TURN NORTHERLY BETWEEN 17-18Z WITH WEAK
FRONTAL PASSAGE BUT WINDS SHOULD REMAIN UNDER 15KT WITH FRONT.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...COOPER
SHORT TERM...ENTREKIN
LONG TERM...KRIEDERMAN
AVIATION...COOPER




AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 625 PM EST MON DEC 21 2015

.SYNOPSIS...
A COASTAL FRONT WILL LIFT NORTH THROUGH AREA TONIGHT.
UNSEASONABLY WARM AND MOIST AIR WILL AFFECT THE AREA WHILE A
SERIES OF UPPER LEVEL DISTURBANCES IMPACT THE SOUTHEAST THROUGH
MID WEEK. HIGH PRESSURE AND UNSEASONABLY WARM TEMPERATURES WILL
PREVAIL LATE WEEK INTO NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
21/23Z SURFACE ANALYSIS PLACED A SHARPENING COASTAL FRONT JUST
OFF THE BEACHES AS WEAK HIGH PRESSURE HOLDS INLAND. MODELS ARE
SIMILAR IN LIFTING THE COASTAL WARM FRONT INLAND OVERNIGHT AS HIGH
PRESSURE RETREATS...LOW-LEVEL JETTING STRENGTHENS AND ISALLOBARIC
FALLS INCREASE ACROSS THE CAROLINA PIEDMONT. ISENTROPIC ASSENT
WILL BE WEAK AT BEST THROUGH THE NIGHT WITH THE MAIN AXIS OF
FORCING FOR ASSENT SETTING UP TO THE WEST. HIGH RESOLUTION MODELS
PAINT A MOSTLY DRY SCENARIO FOR THE AREA THROUGH SUNRISE...WHICH
SEEMS REASONABLE GIVEN THE CURRENT SYNOPTIC SETUP. THERE ARE
SIGNALS THAT A CONCENTRATED AREA OF SHOWERS COULD DEVELOP ALONG
THE UPPER GEORGIA COAST AND FAR SOUTHERN SOUTH CAROLINA COAST
AFTER MIDNIGHT WITHIN AN ENHANCE AREAS OF WARM AIR ADVECTION/
ISENTROPIC ASSENT...BUT THE EXACT PLACEMENT AND TIMING OF THIS IS
A BIT UNCERTAIN. GIVEN THE CURRENT TRENDS NOTED...POPS HAVE BEEN
LOWERED QUITE A BIT IN SOME AREAS WITH HIGHEST POPS STILL
CONCENTRATED ACROSS THE FAR WESTERN AREAS OF JENKINS-SCREVEN AND
ALLENDALE COUNTIES.

THE LOW TEMPERATURE FORECAST IS A CHALLENGE AS MOST OF THE
AVAILABLE GUIDANCE MEMBERS SHOW TEMPERATURES BOTTOMING OUT IN THE
UPPER 50S/LOWER 60S INLAND WITH MID 60S AT THE COAST THIS
EVENING...THEN RISING QUITE A BIT OVERNIGHT...POSSIBLY REACHING
THE UPPER 60S/NEAR 70 IN MANY AREAS BY SUNRISE AS THE WARM SECTOR
BECOMES MORE FIRMLY ESTABLISHED. HAVE ADJUSTED THE HOURLY
TEMPERATURE FORECASTS TO REFLECT A BIT MORE OF AN INCREASE IN
TEMPERATURES OVERNIGHT...BUT NOT QUITE TO THE LEVEL AS DEPICTED BY
THE LATEST H3R AND RAP DATA. FURTHER ADJUSTMENTS WILL BE NEEDED
LATER THIS EVENING AND OVERNIGHT. EARLY LOWS WILL RANGE FROM THE
UPPER 50S FAR INLAND TO THE MID 60S AT THE COAST.

ALREADY SEEING PATCHY SEA FOG OFF OF TYBEE ISLAND EARLY THIS
EVENING. CONDITIONS WILL BECOME INCREASINGLY FAVORABLE FOR SEA
FOG DEVELOPMENT THROUGH THE NIGHT AS WINDS TURN MORE SOUTHERLY AND
PARCEL RESIDENCE TIMES INCREASE OVER THE CHILLY SHELF WATERS.
ATTM IT APPEARS AREAS FROM BEAUFORT AND HILTON HEAD SOUTH ALONG
THE GEORGIA COAST...INCLUDING THE SAVANNAH METRO...IS THE AREA
WHERE FOG PARAMETERS ARE THE BEST ALIGNED. HOWEVER...THERE REMAINS
SOME DOUBT ON EXACTLY HOW WIDESPREAD THE FOG WILL BECOME AS LOW-
LEVEL JETTING INCREASES. MAINTAINED PATCHY FOG FOR NOW...BUT SOME
INCREASE IN THE AREAL COVERAGE MAY BE NEEDED LATER TONIGHT.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY AND TUESDAY NIGHT...THE MAIN SHORTWAVE ALOFT WILL LIFT
NORTHEAST OF THE AREA IN THE LATTER HALF OF THE DAY WITHIN THE DEEP
SOUTHWEST FLOW. WITH DEEP MOISTURE IN PLACE AND PWATS AROUND 1.7
INCHES...COINCIDENT WITH DIVERGENCE IN THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET...THE RAINFALL EVENT IS EXPECTED TO BE AT ITS
PEAK IN THE MORNING HOURS. MODEL CONSENSUS HAS SHIFTED A BIT SUCH
THAT THE AXIS OF HEAVIEST RAIN IS JUST INLAND OF THE FORECAST
AREA...AND POPS HAVE BEEN ADJUSTED SO THAT THE CATEGORICAL POPS ARE
BORDERING THE MIDLANDS AND CENTRAL GEORGIA. THEN ONCE THE SHORTWAVE
SHIFTS DOWNSTREAM...NVA IN ITS WAKE SHOULD CREATE A LULL IN
PRECIPITATION THAT EXTENDS INTO THE EVENING. THEN OVERNIGHT...
ADDITIONAL SHORTWAVE ENERGY IS EXPECTED TO LIFT THROUGH THE AREA
WITH AN ANOTHER SHOT OF RAINFALL. AGAIN THOUGH...THE MODELS ARE
SHOWING THE BEST COMBINATION OF FORCING AND MOISTURE JUST INLAND
OF THE REGION...SO OUR COVERAGE OF PRECIPITATION MAY BE MORE
PERIODIC THROUGH THE NIGHT. LIKELY POPS ARE STILL WARRANTED
THOUGH...WITH A SLIVER OF CATEGORICAL ACROSS THE FAR WESTERN
ZONES. ONCE THE RAIN CLEARS OUT OF THE AREA IN TUESDAY
AFTERNOON...TEMPERATURES SHOULD BE ABLE TO WARM INTO THE LOW
70S...WITH POTENTIAL FOR MID 70S IF ENOUGH SUN CAN BREAK OUT IN
THE AFTERNOON. EXPECT A MINIMAL DIURNAL RANGE IN SUCH A WARM
AIRMASS...WITH LOWS ONLY FALLING INTO THE LOW TO MID 60S.

WEDNESDAY THROUGH THURSDAY...THE OVERALL PATTERN CONTINUES TO
FEATURE SOUTHWEST FLOW ALOFT WITH SHORTWAVE ENERGY PASSING THROUGH.
THIS WILL CHANGE ON THURSDAY AS A STRONG AND DEEP RIDGE CENTERED
OVER THE ATLANTIC PUSHES BACK TO THE WEST BRINGING INCREASINGLY
ANTICYCLONIC FLOW AND BUILDING HEIGHTS ALOFT TO THE SOUTHEAST. AT THE
SURFACE...THE PATTERN WILL LOOK THE SAME EACH DAY WITH PREVAILING
WARM SOUTHERLY FLOW. WEDNESDAY IS POTENTIALLY INTERESTING DAY AS
TEMPERATURES WARM INTO THE UPPER 70S IN MANY AREAS...LEADING TO THE
POTENTIAL FOR SURFACE BASED CAPE VALUES IN EXCESS OF 1000 J/KG. THIS
WOULD OCCUR WITHIN AN ENVIRONMENT OF 40-50 KT OF 0-6 KM SHEAR. THE
MAIN LIMITING FACTOR COULD BE THE OVERALL LACK OF A TRIGGERING
FEATURE AND FOCUSING MECHANISM FOR CONVECTION TO GET GOING AND
ORGANIZE. ALSO...THE MODELS VARY GREATLY WITH THE OVERALL
PRECIPITATION RESPONSE. HAVE MAINTAINED PERSISTENCE FOR NOW WITH A
MENTION OF THUNDERSTORMS. FINALLY FOR THURSDAY...THE FORECAST LOOKS
INCREASINGLY DRY AND WARM. HIGHS FOR THURSDAY ARE FORECAST TO REACH
THE LOW 80S FOR MANY AREAS WHICH WOULD APPROACH OR EXCEED DAILY
RECORDS. SEE CLIMATE SECTION BELOW FOR RECORD DETAILS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LONG TERM TRENDS ARE BECOMING MORE CLEAR...NOW FAVORING A BUILDING
UPPER RIDGE OVER THE SOUTHEAST UNITED STATES LATE WEEK INTO THE
WEEKEND WITH SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. WE
LOWERED RAIN CHANCES DURING THE PERIOD BUT MAINTAINED UNSEASONABLY
WARM TEMPS...POTENTIALLY APPROACHING SOME DAILY RECORDS.

&&

.AVIATION /23Z MONDAY THROUGH SATURDAY/...
KCHS...RISK FOR MVFR CIGS WILL INCREASE LATER THIS EVENING AS A
COASTAL WARM FRONT LIFTS NORTH ACROSS THE TERMINAL. EXPECT
PREVAILING MVFR CIGS BY 08-09Z WITH A SLIGHT RISK FOR IFR
CONDITIONS JUST BEFORE SUNRISE AS AN AREA OF VERY LIGHT
SHOWERS/LOW CIGS MOVES NORTH ACROSS THE TERMINAL. WILL CARRY A
TEMPO GROUP 12-15Z TO COVER THIS POSSIBILITY. EXPECT VFR TO RETURN
BY 17Z.

KSAV...RISK FOR VERY LOW CIGS AND POSSIBLY FOG WILL INCREASE
ACROSS THE TERMINAL BY LATE EVENING AS A COASTAL WARM FRONT LIFTS
NORTH. EXPECT MVFR CIGS BY 04Z WITH IFR CIGS DEVELOPING BY 08Z.
CIGS WILL LIKELY APPROACH ALTERNATE MINIMUMS BY 10Z IF NOT
SOONER. A WEAK AREA OF SHOWERS WILL LIKELY BE PASSING AROUND THE
TERMINAL ATTM SO WILL NOT BRING CONDITIONS TO AIRFIELD MINIMUMS
JUST YET...ALTHOUGH THERE ARE SIGNALS THAT THIS COULD OCCUR. MVFR
WILL RETURN BY 15Z WITH VFR BY 17Z.

EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY TUESDAY
NIGHT AND INTO WEDNESDAY MORNING DUE TO DEVELOPING FOG/STRATUS.
SIMILAR CONDITIONS ARE EXPECTED AGAIN WEDNESDAY NIGHT.

&&

.MARINE...
TONIGHT...WINDS WILL VEER WINDS FROM THE EAST/NORTHEAST TO THE
SOUTH BY THE END OF THE PERIOD AS A COASTAL WARM FRONT LIFTS
INLAND. SPEEDS 5 KT EARLY WILL INCREASE TO 10-15 KT...EXCEPT 15-20
KT GEORGIA OFFSHORE WATERS AND CHARLESTON COUNTY WATERS. SEAS ON
AVERAGE WILL BE 2-4 FT IN THE NEARSHORE WATERS...3-5 FT IN THE
OUTER LEGS...ALTHOUGH IT IS POSSIBLE SEAS COULD BREACH 6
FT...ESPECIALLY BEHIND 40 NM. A SMALL CRAFT ADVISORY MAY BE
NEEDED.

TUESDAY THROUGH SATURDAY...THE OVERALL PATTERN WILL REMAIN THE
SAME INTO THE UPCOMING WEEKEND. THE LOCAL WATERS WILL BE
POSITIONED ON THE WESTERN PERIPHERY OF HIGH PRESSURE CENTERED WELL
OVER THE ATLANTIC...PROMOTING PERSISTENT SOUTHERLY FLOW THROUGH
THE PERIOD. WIND SPEEDS WILL TOP OUT IN THE 15-20 KT RANGE AT
TIMES...MAINLY IN THE OUTER WATERS. SEAS WILL STEADILY BUILD
THROUGH THE MID TO LATE WEEK TIME PERIOD AND SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED.

SEA FOG...ALREADY SEEING PATCHY SEA FOG OFF OF TYBEE ISLAND EARLY
THIS EVENING. INCREASING DEWPOINTS OVER THE COOLER SHELF WATERS
WILL LIKELY BRING ANOTHER BOUT OF SEA FOG AS WINDS TURN MORE
SOUTHERLY AND PARCEL RESIDENCE TIMES OVER THE CHILLY SHELF WATERS
INCREASE. ONCE THE SEA FOG DEVELOPS...THE PATTERN WOULD FAVOR IT
REMAINING IN PLACE FOR MUCH OF THE WEEK. WILL MAINTAIN PATCHY FOG
IN THE COASTAL WATERS FORECAST AND MENTION OF POTENTIALLY DENSE
SEA FOG IN THE HAZARDOUS WEATHER OUTLOOK.

&&

.CLIMATE...
RECORD HIGHS FOR DECEMBER 23RD...
KCHS...82/2013.
KCXM...76/1990.
KSAV...81/1956.

RECORD HIGHS FOR DECEMBER 24TH...
KCHS...76/1988.
KCXM...76/1921.
KSAV...80/1931.

RECORD HIGHS FOR DECEMBER 25TH...
KCHS...80/2008.
KCXM...76/2008 (MULTIPLE YEARS).
KSAV...80/2008 (MULTIPLE YEARS).

RECORD HIGHS FOR DECEMBER 26TH...
KCHS...78/1942.
KCXM...74/1982 (MULTIPLE YEARS).
KSAV...79/1987.

RECORD HIGH MINIMUMS FOR DECEMBER 23RD...
KCHS...66/1990.
KCXM...68/1990.
KSAV...65/1990.

RECORD HIGH MINIMUMS FOR DECEMBER 24TH...
KCHS...60/1964.
KCXM...60/1964.
KSAV...62/1879.

RECORD HIGH MINIMUMS FOR DECEMBER 25TH...
KCHS...62/2008 (MULTIPLE YEARS).
KCXM...63/1964 (MULTIPLE YEARS).
KSAV...65/1932.

RECORD HIGH MINIMUMS FOR DECEMBER 26TH...
KCHS...67/1964.
KCXM...66/1964.
KSAV...63/1987 (MULTIPLE YEARS).

&&

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

&&

$$

ST




AREA FORECAST DISCUSSION

NWS NORTHERN INDIANA

 343 PM EST SUN DEC 20 2015

.SYNOPSIS...
ISSUED AT 336 PM EST SUN DEC 20 2015

RAIN WILL OVERSPREAD THE AREA TONIGHT AND CONTINUE INTO MONDAY
MORNING. AFTER A BRIEF DRY PERIOD...SHOWER CHANCES WILL ARRIVE MID
WEEK AND PERSIST ON AND OFF INTO THE WEEKEND. ABOVE TO WELL ABOVE
NORMAL TEMPERATURES WILL DOMINATE MOST OF THE PERIOD...WITH RECORD
HIGH TEMPERATURES LIKELY TO BE BROKEN WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 336 PM EST SUN DEC 20 2015

WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING UPPER TROF
OVER THE FOUR CORNERS WITH POTENT 120KT UPPER JET MOVING UP THE EAST
SIDE OF THE TROF AXIS. THIS ENERGY WILL EJECT EASTWARD AND HELP
ORGANIZE DEVELOPING SURFACE LOW IN THE PLAINS. DESPITE PROGRESSIVE
NATURE OF THIS SYSTEM...IMPRESSIVE DYNAMICS WILL AID IN DECENT
MOISTURE TRANSPORT INTO THE REGION OVERNIGHT AND SUPPORT WIDESPREAD
LIGHT TO MODERATE RAIN. GOOD ISENTROPIC ASCENT AHEAD OF THIS SYSTEM
WILL RAPIDLY SATURATE THE LOW LEVELS AFTER 06Z IN OUR WESTERN CWA
WITH ARRIVAL OF 60KT LLJ EARLY MONDAY MORNING. WILL TREND ARRIVAL OF
PRECIP IN A NW/SE ORIENTATION WITH NW CWA BECOMING LIKELY SHORTLY
AROUND 06Z AND SE BY 09Z MONDAY. MODELS IN DECENT AGREEMENT WITH
BRINGING WEAK DRY SLOT INTO THE AREA MONDAY AFTERNOON WHICH WILL
DIMINISH...BUT NOT ELIMINATE...POPS DOWN TO CHANCE/SLIGHT CHANCE.
WARM AIR ADVECTION PATTERN ON STRONG SOUTHERLY FLOW WILL LIMIT
DIURNAL TEMP CHANGES DURING THE PERIOD WITH LOWS TONIGHT NEAR 40F
AND HIGHS NEAR 50F OVER MOST OF THE CWA MONDAY.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 336 PM EST SUN DEC 20 2015

RETURN TO ABOVE TO WELL ABOVE NORMAL TEMPERATURES FOR MOST IF NOT
ALL THE FORECAST PERIOD...WITH A FEW CHANCES FOR
RAINFALL...ESPECIALLY MIDWEEK.

LOW PRESSURE WILL BE QUICKLY EXITING TO THE NORTHEAST OF THE AREA
WITH A TRAILING DISTURBANCE MOVING THROUGH THE AREA MONDAY NIGHT.
SOME WEAK LIFT IS DEPICTED IN ALL MODELS IN THE LOWEST LEVELS WITH
NAM THE MOST PRONOUNCED. NOT SURE ABOUT HOW MUCH OF THE PRECIP WILL
BE MEASURABLE RAIN VS DRIZZLE GIVEN SHALLOW NATURE OF LIFT. WILL
KEEP WITH SLGT CHC TO CHC POPS AND ADD MENTION OF PATCHY DRIZZLE
THROUGH THE NIGHT. LITTLE SIGNIFICANT CHANGE IN SURFACE TEMPERATURES
MON NGT INTO TUESDAY WITH ONLY A GLANCING BLOW OF SLIGHTLY COLDER
BUT STILL ABOVE NORMAL) AIR.

FOCUS THEN SHIFTS TO DEEP TROUGH DIGGING INTO THE CENTRAL PLAINS
WHICH WILL EJECT TOWARDS THE REGION WEDNESDAY INTO WEDNESDAY NIGHT
ADVECTING WARMER AND MORE HUMID AIR (PWATS 0.75 TO 1 INCH) INTO THE
REGION. WITH CURRENTLY FORECASTED HIGHS OF 60 OR HIGHER...RECORD
HIGH TEMPERATURES WILL BE BROKEN FOR BOTH SOUTH BEND AND FT WAYNE
(59 IN 1933 AND 59 IN 1941 RESPECTIVELY). SHOWERS CHANCES WILL
INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT
WITH ALL LOCATIONS TO SEE AT LEAST SOME MEASURABLE RAINFALL.
HEAVIEST AXIS OF RAINFALL LOOKS TO REMAIN INTO ILLINOIS. NEIGHBORS
TO THE WEST AND SOUTH HAVE ADDED MENTION OF THUNDER AND WHILE
NAM/GFS DO ATTEMPT BRING A NARROW RIBBON OF NEAR ZERO SHOWALTERS IN
BETWEEN 00Z AND 6Z NOT CONVINCED COVERAGE (IF ANY) WILL BE ENOUGH TO
WARRANT A MENTION.

GIVEN THE WESTERLY TRACK OF THE LOW AND RELOADING OF AN EVEN
STRONGER TROUGH IN THE WEST...NO MAJOR COLD AIR ARRIVES WITH
READINGS DROPPING BACK TO THE 40S AND 50S...STILL WELL ABOVE THE
NORMALS IN THE UPPER 30S AND NOT BODING WELL FOR ANY CHANCES OF A
WHITE CHRISTMAS FOR THE AREA. LARGE MODEL DIFFERENCES EXIST WITH
HANDLING OF CLOSED UPPER LOW AND ITS IMPACTS THIS WEEKEND. HAVE
CONTINUED WITH SLGT CHC TO CHC POPS STARTING FRIDAY NIGHT AND
PERSISTING THROUGH THE WEEKEND. TEMPERATURES MAY RETURN TO NEAR
NORMAL LEVELS AT THE END OF THE PERIOD BUT GIVEN LARGE MODEL
DIFFERENCES NOT SURE IF THIS WILL HOLD TRUE OR NOT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED
AT 1230 PM EST SUN DEC 20 2015

VFR CONDITIONS TO BEGIN THE TAF PERIOD WITH HIGH CIRRUS SHIELD THIS
AFTERNOON BUT WITH GUSTY SOUTH WINDS. AS GUSTY CONDITIONS DIMINISH
OVERNIGHT AND LOW LEVEL JET STRENGTHENS...LLWS ANTICIPATED AT BOTH
SITES WITH PEAK NEAR 60KTS AT 2KFT. RAIN EXPECTED TO DEVELOP
OVERNIGHT INTO EARLY MONDAY MORNING AHEAD OF APPROACHING LOW
PRESSURE SYSTEM AND WILL BRING IFR CONDITIONS ON MONDAY...GOOD
CHANCE AT EVEN DROPPING TO LIFR BUT NEAR THE END OF TAF PERIOD SO
WILL HOLD OFF FOR NOW.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST MONDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...FISHER
SHORT TERM...JAL
LONG TERM...FISHER
AVIATION...LOGSDON


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA




AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 316 AM EST SUN DEC 20 2015

.UPDATE...
THE LONG TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 125 PM EST SAT DEC 19 2015

HIGH PRESSURE OVER THE DEEP SOUTH WILL PROVIDE DRY WEATHER FOR
CENTRAL INDIANA THROUGH SUNDAY EVENING. SOUTHERLY WINDS WILL
RETURN TO CENTRAL INDIANA ON SUNDAY...ALLOWING FOR A WARMER DAY.

LOW PRESSURE AND A COLD FRONT APPROACHING THE GREAT LAKES ON LATE
SUNDAY NIGHT AND MONDAY WILL BRING CHANCES FOR RAIN SHOWERS BACK
TO CENTRAL INDIANA. EARLY NEXT WORK WEEK...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES WILL PUSH ACROSS THE REGION...CONTINUING THE
CHANCES FOR RAIN.

MILD AIR IS EXPECTED TO REMAIN ACROSS THE REGION THROUGH NEXT
WEEK. THIS WILL RESULT IN A WARM AND GREEN CHRISTMAS.

&&

.NEAR TERM /OVERNIGHT/...
ISSUED AT 944 PM EST SAT DEC 19 2015

CLEAR SKIES ACROSS CENTRAL INDIANA THIS EVENING WITH HIGH PRESSURE
CENTERED OVER EASTERN TENNESSEE. WITH LIGHT FLOW AND A DRY
AIRMASS...TEMPS HAVE FALLEN QUICKLY THIS EVENING INTO THE MID AND
UPPER 20S AT 0230Z.

LITTLE CHANGE NEEDED FOR THE EVENING UPDATE AS CURRENT FORECAST IN
EXCELLENT SHAPE. WITH ONLY SOME THIN CIRRUS DRIFTING INTO THE
REGION FROM THE WEST AFTER MIDNIGHT...MAIN FOCUS IS ON TEMPS THE
REST OF THE NIGHT. DECISION TO TREND LOWS TOWARDS THE COOL END OF
GUIDANCE WAS A GOOD CALL...AS MANY AREAS ARE ALREADY WITHIN A
COUPLE DEGREES OF FORECAST LOWS. EXPECT LOWS TO BE REACHED AROUND
OR SHORTLY AFTER 06Z WITH TEMPS STEADYING OR SLOWLY RISING
THEREAFTER AS WARM ADVECTION COMMENCES AND SOUTHERLY WINDS
STRENGTHEN TOWARDS DAYBREAK. UTILIZED RUC HOURLY DATA FOR
TEMPERATURE INTERPOLATION OVERNIGHT WITH TEMPS RECOVERING INTO THE
UPPER 20S AND LOWER 30S BY DAYBREAK.

ZONE AND GRID UPDATES OUT.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...

ISSUED AT 125 PM EST SAT DEC 19 2015

DRY WEATHER WILL CONTINUE TO BE EXPECTED ON SUNDAY AND SUNDAY
NIGHT AS WARM AIR ADVECTION CONTINUES THROUGH THE DAY ON SOUTHWEST
FLOW ALOFT. MODEL SUGGEST 850MB TEMPS REACHING NEAR 8C BY 00Z
MONDAY. TIME HEIGHT SECTIONS THROUGH THE DAY SUGGEST SATURATION
ALOFT...THUS WILL TREND TOWARD A PARTLY CLOUDY SKY. GIVEN THE
STRONG WARM AIR ADVECTION AND SOUTHWESTERLY FLOW WILL TREND HIGHS
AT OR ABOVE MAVMOS.

INCREASING CLOUDS WILL BE EXPECTED ON SUNDAY NIGHT AS MODELS
SUGGEST A SHORT WAVE EMBEDDED WITHIN THE SOUTHWEST FLOW ALOFT TO
PUSH ACROSS THE STATE AFTER 06Z. FORECAST SOUNDINGS AND TIME TIME
HEIGHTS INDICATE DEEP SATURATION. THE 300K GFS ISENTROPIC SURFACE
SHOWS A SURGE OF MOISTURE WITH SPECIFIC HUMIDITIES REACHING OVER
4 G/KG ALONG WITH GOOD LIFT. THUS RAIN WILL BE EXPECTED ON SUNDAY
NIGHT AFTER 06Z...AND WILL TREND POPS AT OR ABOVE GUIDANCE. GIVEN
THE CLOUDS AND EXPECTED PRECIP WILL TREND LOWS WARMER THAN
MAVMOS.

MODELS SUGGEST THAT ON MONDAY THROUGH TUESDAY THE ASSOCIATED LOW
PRESSURE SYSTEM WITH THE COLD FRONT PULLS QUICKLY TO THE
NORTHEAST WHILE THE COLD FRONT STALLS AND ELONGATES ACROSS
CENTRAL INDIANA AND SOUTHERN INDIANA. MEANWHILE ALOFT...MAINLY
QUICK ZONAL FLOW REMAINS IN PLACE...ALLOWING A SERIES OF WEAK
SHORT WAVES TO PUSH IN TO THE OHIO VALLEY THROUGH TUESDAY. GIVEN
THE POOR ORGANIZATION...BUT DECENT FORCING AND A LINGERING
BOUNDARY IN PLACE ACROSS THE AREA...SOME LOW CHANCE POPS WILL BE
NEEDED...FOR LIGHT PRECIP EVENTS. WILL STICK CLOSE TO MAVMOS POPS
THROUGH TUESDAY AND TREND LOWS WARMER THAN MAVMOS AND STICK CLOSE
ON HIGHS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/...

ISSUED AT 313 AM EST SUN DEC 20 2015

MODELS DEPICT AND UPPER RIDGE OVER THE EASTERN STATES WITH MEAN
TROUGHING TO THE WEST. ON AND OFF CHANCES FOR RAIN WILL PREVAIL
THROUGH THE EXTENDED PERIOD AS PERIODIC DISTURBANCES EJECT OUT FROM
THE TROUGH AND IMPACT THIS REGION. EARLY ON IN THIS FORECAST
PERIOD...A STRONG UPPER WAVE WILL BE PASSING THROUGH THE LOCAL AREA
WEDNESDAY INTO WEDNESDAY NIGHT. THERE APPEARS TO BE ENOUGH FORCING
AND INSTABILITY ASSOCIATED WITH THIS FEATURE TO WARRANT SOME CHANCES
FOR CONVECTION DURING THIS TIMEFRAME. HAVE CONTINUED TO MENTION
CHANCES FOR STORMS ALONG WITH LIKELY TO CATEGORICAL POPS.

THE NEXT MAJOR DISTURBANCE TO MOVE THROUGH MAY BEGIN AS EARLY AS
CHRISTMAS DAY...AND CONTINUE INTO SATURDAY WITH WEAK CHANCES FOR
LIGHT RAIN. THERE IS SOME DISAGREEMENT AMONGST THE GUIDANCE SO
CONFIDENCE AND THUS POPS ARE LOW AT THIS TIME.

&&

.AVIATION /DISCUSSION FOR THE 200600Z TAF ISSUANCE/...

ISSUED AT 313 AM EST SUN DEC 20 2015

0815Z UPDATE...NO CHANGES NEEDED AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS.

HIGH CONFIDENCE IN VFR CONDITIONS THROUGH AT LEAST 04Z SUNDAY.

PER MODEL RH TIME SECTIONS AND SATELLITE TRENDS...SHOULD ONLY SEE
INCREASING CIRRUS OVERNIGHT AND TODAY...AS AN UPPER RIDGE PASSES
THROUGH RESULTING IN SOUTHWEST FLOW ALOFT. DO NOT EXPECT FOG AS LATE
EVENING DEW POINT SPREADS REMAINED ABOVE 5 DEGREES AND SOUTH WINDS
WILL INCREASE TO AROUND 6 KNOTS OVERNIGHT.

LOWER CLOUDS AND A FEW RAIN SHOWERS ARE EXPECTED TO MOVE IN AFTER
04Z MONDAY AS SOUTHERLY FLOW BRINGS IN MOISTURE OFF THE GULF AHEAD
OF A WESTERN GREAT LAKES AND SOUTHERN PLAINS FRONTAL SYSTEM.

THE SOUTHERLY WINDS WILL INCREASE AFTER 15Z TO NEAR 15 KNOTS WITH
GUSTS TO 20 TO 25 KNOTS.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....SMF
AVIATION...SMF/MK



AREA FORECAST DISCUSSION

National Weather Service Topeka KS

 1143 AM CST SUN DEC 20 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 257 AM CST SUN DEC 20 2015

Winds already picking up in the early morning hours, with winds
aloft forecast to increase and stay up through the day today. This
has kept overnight lows up in the 40s most areas.  As the boundary
layer mixes out this morning, RAP and GFS suggest winds at the top
of the mixed layer are close to 50 kts.  As a result, expect high
temperatures to make it into the middle/upper50s, and wind speeds to
gust near wind advisory criteria of 40 kts.  Will hoist a wind
advisory for those counties along and south of I-70.  Still a chance
for some light drizzle and light rain to develop late this morning
in the WAA regime, followed by precip chances continuing due to the
shortwave trof moving eastward out of the high plains later this
evening. These showers could also aid in mixing down some of the
stronger wind speeds through the day today.

Both GFS and NAM indicating just a few hours with some weak
instability in the column in the midnight to 3am timeframe as the
stronger lift and cold pool aloft move over the eastern part of the
state.  Have left thunder out at this time given small window, but
is worth mentioning here.  As trof moves eastward, cooler air moves
in behind and lows fall into he 20s to middle 30s.

.LONG TERM...(Monday through Saturday)
Issued at 257 AM CST SUN DEC 20 2015

On Monday another mid level trough tracks over the central US, which
should not have much effect on the overall weather. Highs will be
cooler in the mid to upper 40s. On Tuesday return flow quickly
develops as yet another shortwave approaches from the west, which
will allow temperatures to warm back into the 50s. This shortwave
trough appears to deepen Tuesday night as it passes over the
forecast area. Increased moisture and lift as well as an advancing
cold front could support rain Wednesday morning and into the
afternoon. This precip appears to stay confined to portions of
eastern KS. Towards the end of the week a few of the models continue
to bring out weak shortwaves that could cause light precip, but
confidence in timing and location is low at this point. Models
continue to show a strong system over the southern Rockies over the
weekend, but also continue to struggle on how to evolve that
system.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1132 AM CST SUN DEC 20 2015

Somewhat of a complicated forecast for the next 18-24hrs. Gusty
southerly winds continue through the afternoon. Expecting winds to
continue to be brisk this evening before the system to the west of
the terminals pushes through. There is a chance for some very
isolated thunderstorm activity to develop for a period tonight as
the upper low advances into the region. Have reflected this as
VCTS at the KTOP/KFOE terminals. A general lack of instability
further west doesn`t seem to support the same setup near KMHK.
Winds change to the West/northwest by Monday morning.

&&

.TOP Watches/Warnings/Advisories...
Wind Advisory until 6 PM CST this evening for KSZ035>040-054>056-
058-059.

&&

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...Drake




AREA FORECAST DISCUSSION

National Weather Service Topeka KS

 522 AM CST SUN DEC 20 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 257 AM CST SUN DEC 20 2015

Winds already picking up in the early morning hours, with winds
aloft forecast to increase and stay up through the day today. This
has kept overnight lows up in the 40s most areas.  As the boundary
layer mixes out this morning, RAP and GFS suggest winds at the top
of the mixed layer are close to 50 kts.  As a result, expect high
temperatures to make it into the middle/upper50s, and wind speeds to
gust near wind advisory criteria of 40 kts.  Will hoist a wind
advisory for those counties along and south of I-70.  Still a chance
for some light drizzle and light rain to develop late this morning
in the WAA regime, followed by precip chances continuing due to the
shortwave trof moving eastward out of the high plains later this
evening. These showers could also aid in mixing down some of the
stronger wind speeds through the day today.

Both GFS and NAM indicating just a few hours with some weak
instability in the column in the midnight to 3am timeframe as the
stronger lift and cold pool aloft move over the eastern part of the
state.  Have left thunder out at this time given small window, but
is worth mentioning here.  As trof moves eastward, cooler air moves
in behind and lows fall into he 20s to middle 30s.

.LONG TERM...(Monday through Saturday)
Issued at 257 AM CST SUN DEC 20 2015

On Monday another mid level trough tracks over the central US, which
should not have much effect on the overall weather. Highs will be
cooler in the mid to upper 40s. On Tuesday return flow quickly
develops as yet another shortwave approaches from the west, which
will allow temperatures to warm back into the 50s. This shortwave
trough appears to deepen Tuesday night as it passes over the
forecast area. Increased moisture and lift as well as an advancing
cold front could support rain Wednesday morning and into the
afternoon. This precip appears to stay confined to portions of
eastern KS. Towards the end of the week a few of the models continue
to bring out weak shortwaves that could cause light precip, but
confidence in timing and location is low at this point. Models
continue to show a strong system over the southern Rockies over the
weekend, but also continue to struggle on how to evolve that
system.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 521 AM CST SUN DEC 20 2015

Winds have become gusty for the most part this morning and should
increase a bit more in the late morning hours. Winds start to
diminish in the evening hours before the next wind shift after
midnight. Kept light rain late in the period with MVFR cigs.

&&

.TOP Watches/Warnings/Advisories...
Wind Advisory until 6 PM CST this evening for KSZ035>040-054>056-
058-059.

&&

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...67




AREA FORECAST DISCUSSION

NWS GOODLAND KS

 348 AM MST SUN DEC 20 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 157 AM MST SUN DEC 20 2015

THE SHORT TERM PERIOD REMAINS WARMER THAN AVERAGE AND DRY.

A WEAK SHORT WAVE TROUGH ALOFT LIFTS OUT ACROSS THE FORECAST AREA
EARLY THIS MORNING TO BE FOLLOWED BY A STRONGER SHORT WAVE TROUGH
EMBEDDED IN THE UPPER FLOW LATE THIS AFTERNOON AND EARLY EVENING.
THIS IS ALL ON THE HEELS OF A COLD FRONT MOVING THROUGH THE
FORECAST AREA TODAY...COOLING TEMPERATURES FROM YESTERDAY BY
ABOUT 5-10 DEGREES ACROSS MAINLY THE NORTHWEST SECTIONS OF THE
FORECAST AREA. THERE IS A POSSIBILITY OF MAINLY THE SOUTHWESTERN
SECTIONS SEEING A SPRINKLE OR FLURRY THIS EVENING AS THE SHORT
WAVE TROUGH ALOFT MOVES ACROSS THE AREA...BUT DO NOT EXPECT ANY
MEASURABLE PRECIPITATION GIVEN THE FAST MOVING NATURE OF THE OPEN
WAVE AND THE LIMITED AMOUNT OF MOISTURE IN THE COLUMN.

ANOTHER FAST MOVING SHORT WAVE TROUGH ALOFT MOVES ACROSS THE
REGION EARLY MONDAY WITH WESTERLY FLOW ALOFT. THE WESTERLY FLOW
STARTS TURNING MORE SOUTHWESTERLY AS IT INCREASES AHEAD OF THE
NEXT TROUGH THAT WILL BE DEEPENING OVER THE INTERMOUNTAIN REGION
ON TUESDAY BEFORE IT MOVES EAST OF THE ROCKIES TUESDAY NIGHT.
SURFACE HIGH PRESSURE MOVES ACROSS THE FORECAST AREA ON MONDAY WITH
A LEE TROUGH DEEPENING ALONG THE FRONT RANGE MONDAY NIGHT AND
EARLY TUESDAY BEFORE MOVING EAST OFF THE FRONT RANGE LATE TUESDAY
AFTERNOON AND EVENING JUST AHEAD OF THE UPPER TROUGH. THERE
APPEARS TO BE A POSSIBILITY OF SOME VERY LIGHT PRECIPITATION WITH
THE TROUGH TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. THE GFS
FAVORS A LITTLE MORE QPF THAN THE ECMWF...BUT THE LATEST ECMWF IS
NOW SHOWING VERY LIGHT ACCUMULATIONS WITH THE SUPERBLEND YET ADOPT
THIS. HAVE SHOWN A VERY SMALL INCREASE IN POPS DURING THE TUESDAY
EVENING TIME PERIOD...WHICH COULD DEFINITELY SEE SOME INCREASE IF
CURRENT TRENDS CONTINUE.

TEMPERATURES THROUGH THIS PERIOD WILL VARY LITTLE WITH GENERALLY
WARMER THAN NORMAL READINGS AND DRY CONDITIONS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 157 AM MST SUN DEC 20 2015

MID AND UPPER LEVEL PATTERN IS EXPECTED TO
CHANGE FOR THESE PERIODS POSSIBLY LEADING TO COOLER TEMPERATURES AND
PRECIP CHANCES RETURNING.

WEDNESDAY...SHORTWAVE TROUGH PASSING THROUGH W/NW FLOW ACROSS THE
NORTHERN PLAINS SHOULD KICK A WEAK COLD FRONT SOUTH. DESPITE
VARIANCES IN STRENGTH OF THIS FEATURE THERE WOULD BE SOME FORCING
AND MODELS ARE SHOWING LIGHT QPF. HOWEVER MOISTURE PROFILES CONTINUE
TO INDICATE A DEEP DRY LAYER OVER OUR CWA BELONG 500 MB AND
CONFIDENCE IN ANYTHING REACHING THE GROUND IS LOW.

THURSDAY-SUNDAY...THERE IS SIGNIFICANT VARIANCE IN THE EVOLUTION OF A
CLOSED UPPER LOW EXPECTED TO DEVELOP OVER THE WESTERN US AND
EVENTUALLY MOVE ACROSS THE PLAINS DURING THESE PERIODS. CURRENT
TREND IS TOWARDS LOWERING HEIGHTS AND COOLER TEMPERATURES THAN
PREVIOUSLY INDICATED AND BLEND REFLECTED THIS AND THIS SHOULD
MINIMIZE ERROR IN THIS HIGHLY UNCERTAIN PATTERN. FOR EXAMPLE...THE
TIMING OF A COLD FRONT VARIES BY ALMOST 12HR BETWEEN MODELS
RESULTING IN A HIGH DEGREE OF UNCERTAINTY ON HIGH TEMPS CHRISTMAS
WITH GFS INDICATING HIGHS POSSIBLY AROUND FREEZING...WHILE ECMWF
KEEPS PREFRONTAL TROUGH AND WAA IN PLACE CHRISTMAS DAY (HIGHS IN
50S).

HOW THIS SYSTEM EVOLVES WILL IMPACT BOTH TEMP PROFILES (PRECIP TYPE)
AND ANY CHANCE FOR MEASURABLE PRECIP. LATEST ECMWF INDICATES THE
POSSIBLY FOR A WINTER STORM DEVELOPING OVER OUR CWA BY SATURDAY
NIGHT. GFS SHOWS THE OPPOSITE AND HAS BEST CHANCE FOR PRECIP (LIKELY
SNOW) THURSDAY NIGHT AND THEN DRY THROUGH THE REMAINING PERIODS AS
THE CLOSED MID/UPPER LOW DRIFTS TO THE SOUTHWEST. 00Z GEFS ENSEMBLES
SHOW A HIGH DEGREE OF VARIANCE WITH MEMBERS SHOWING LITTLE IN THE
WAY OF CLUSTERING TOWARDS ANY ONE SOLUTION. IT MIGHT BE TEMPTING
TO FAVOR THE GFS SOLUTION IN THE SPIRIT OF THE HOLIDAYS AND THE
DESIRE FOR A LIGHT LAYER OF SNOW CHRISTMAS MORNING BUT THERE IS
JUST NOT ENOUGH SUPPORT OR CONSISTENCY. THE ECMWF IS CONCERNING
CONSIDERING THE BUSY TRAVEL WEEKEND...BUT AGAIN THERE IS NO RUN TO
RUN HISTORY TO BUY INTO THIS ONE SOLUTION. I STAYED IN LINE WITH
MEAN/BLEND APPROACH AND KEPT 20 POPS IN PLACE THURSDAY NIGHT
(CHRISTMAS EVE NIGHT) THROUGH SATURDAY NIGHT OVER PARTS OF OUR
CWA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 930 PM MST SAT DEC 19 2015

FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
WINDS AT KGLD FROM THE SOUTHWEST NEAR 12KTS FROM TAF ISSUANCE
THROUGH 08Z THEN A GRADUAL VEERING TO THE WEST-NORTHWEST BY
15Z...NORTHWEST FROM 20Z THROUGH THE REST OF THE TAF PERIOD.
SPEEDS GENERALLY UNDER 10KTS. FOR KMCK...LIGHT AND VARIABLE WINDS
FROM TAF ISSUANCE THROUGH 17Z THEN NORTHWEST 6-10KTS FROM 18Z
THROUGH THE REST OF THE TAF PERIOD. MID AND MOSTLY HIGH CLOUDS
EXPECTED THROUGH THE PERIOD. HAVE A BIT OF CONCERN IN THE 22Z-04Z
TIMEFRAME AT BOTH TERMINALS. ITS DURING THIS TIME THAT AN UPPER
TROUGH OF LOW PRESSURE MOVES ACROSS THE AREA. NAM MOISTURE CROSS
SECTIONS SHOW LOW LEVEL MOISTURE INCREASING WITH THE TROUGH
PASSAGE POSSIBLY CREATING SOME MVFR CLOUDINESS AND POSSIBLY SOME
LIGHT RAIN SHOWERS. HRRR MODEL ALSO SHOWING SOME LIGHT PRECIP AS
WELL. WILL HOLD OFF ON INTRODUCING ANY PRECIP MENTION AS CURRENT
FORECAST IS DRY. WILL ALSO HOLD OFF ANY SUB VFR CLOUDINESS AS THE
NAM APPEARS TO BE THE ONLY MODEL SHOWING MVFR CIGS AT PRESENT
TIME.


&&

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

$$

SHORT TERM...LOCKHART
LONG TERM...DR
AVIATION...99




AREA FORECAST DISCUSSION

National Weather Service Topeka KS

 258 AM CST SUN DEC 20 2015

.SHORT TERM...(Today and Tonight)
Issued at 257 AM CST SUN DEC 20 2015

Winds already picking up in the early morning hours, with winds
aloft forecast to increase and stay up through the day today. This
has kept overnight lows up in the 40s most areas.  As the boundary
layer mixes out this morning, RAP and GFS suggest winds at the top
of the mixed layer are close to 50 kts.  As a result, expect high
temperatures to make it into the middle/upper50s, and wind speeds to
gust near wind advisory criteria of 40 kts.  Will hoist a wind
advisory for those counties along and south of I-70.  Still a chance
for some light drizzle and light rain to develop late this morning
in the WAA regime, followed by precip chances continuing due to the
shortwave trof moving eastward out of the high plains later this
evening. These showers could also aid in mixing down some of the
stronger wind speeds through the day today.

Both GFS and NAM indicating just a few hours with some weak
instability in the column in the midnight to 3am timeframe as the
stronger lift and cold pool aloft move over the eastern part of the
state.  Have left thunder out at this time given small window, but
is worth mentioning here.  As trof moves eastward, cooler air moves
in behind and lows fall into he 20s to middle 30s.

.LONG TERM...(Monday through Saturday)
Issued at 257 AM CST SUN DEC 20 2015

On Monday another mid level trough tracks over the central US, which
should not have much effect on the overall weather. Highs will be
cooler in the mid to upper 40s. On Tuesday return flow quickly
develops as yet another shortwave approaches from the west, which
will allow temperatures to warm back into the 50s. This shortwave
trough appears to deepen Tuesday night as it passes over the
forecast area. Increased moisture and lift as well as an advancing
cold front could support rain Wednesday morning and into the
afternoon. This precip appears to stay confined to portions of
eastern KS. Towards the end of the week a few of the models continue
to bring out weak shortwaves that could cause light precip, but
confidence in timing and location is low at this point. Models
continue to show a strong system over the southern Rockies over the
weekend, but also continue to struggle on how to evolve that
system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1114 PM CST SAT DEC 19 2015

Wind gusts will slowly increase overnight while 2000 ft AGL winds
near 60 kts will cause llws until surface winds can increase after
09Z. It currently appears that any morning and early afternoon low
cloud cover will remain scattered or less, so have held off MVFR
cigs until deeper moisture and lift moves over TAF sites after
01Z, which will also promote scattered showers through the end of
the TAF period.


&&

.TOP Watches/Warnings/Advisories...
Wind Advisory from 8 AM this morning to 6 PM CST this evening
for KSZ035>040-054>056-058-059.

&&

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...Barjenbruch



AREA FORECAST DISCUSSION

NWS GOODLAND KS

 930 PM MST SAT DEC 19 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 105 PM MST SAT DEC 19 2015

AS OF 2 PM CST...1 PM MST...THE SKY ACROSS THE TRI-STATE REGION IS
BECOMING OVERCAST AS CIRRUS SPREADS IN FROM THE SOUTHWEST.
TEMPERATURES RANGED FROM THE UPPER 40S OVER NORTHEAST COLORADO AND
NORTH CENTRAL KANSAS TO THE UPPER 50S TO NEAR 60 GENERALLY ALONG THE
KANSAS/COLORADO BORDER. WINDS ARE SOUTH TO SOUTHWEST AT 10 TO 15
MPH. AT THE SURFACE...A LEE TROUGH IS CENTERED NEAR THE DENVER METRO
AREA WHILE SURFACE HIGH PRESSURE RESIDES OVER THE SOUTHEASTERN
UNITED STATES. ALOFT...A TROUGH OF LOW PRESSURE IS MAKING LANDFALL
ALONG THE CALIFORNIA COASTLINE. ACCORDING TO WATER VAPOR IMAGERY...A
RICH PLUME OF MOISTURE ALOFT EXTENDS FROM THE EAST CENTRAL PACIFIC
OCEAN TO SOUTHERN COLORADO.

FOR TONIGHT THROUGH TOMORROW...ABOVE NORMAL TEMPERATURES AND DRY
WEATHER ARE EXPECTED TO PERSIST. THE MOISTURE ADVECTION FROM THE
PACIFIC OCEAN PREVIOUSLY MENTIONED WILL ONLY RESULT IN WIDESPREAD
PARTLY CLOUDY/OVERCAST SKIES DUE TO CIRRUS. A WEAK COLD FRONT SHOULD
MOVE INTO THE REGION TOMORROW AFTERNOON. HOWEVER...DUE TO THE LATER
ARRIVAL OF THE FRONT...ANTICIPATE WARMER TEMPERATURES SIMILAR TO
WHAT HAS OCCURRED TODAY. WITH LITTLE TO NO MOISTURE BELOW 500
MB...DRY WEATHER IS ASSURED. SOUTH WINDS THIS AFTERNOON GRADUALLY
VEER TO THE WEST TONIGHT BEFORE SHIFTING TO THE NORTHWEST BEHIND THE
COLD FRONT.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 105 PM MST SAT DEC 19 2015

FOR THE TAIL-END OF THIS WEEKEND RIGHT ON THROUGH THE UPCOMING
WEEK...THE TRI STATE REGION WILL SEE MAINLY DRY CONDITIONS INTO
FRIDAY WITH THE CHANCE FOR LIGHT WINTRY PRECIPITATION FRIDAY NIGHT
INTO THE DAY SATURDAY.

MID LEVEL FLOW DURING THE WEEK WILL START OFF MAINLY WNW WITH A
SHIFT TO THE WSW AS A CUTOFF LOW MOVES FROM THE PACIFIC COAST INTO
THE CENTRAL/SOUTHERN ROCKIES. BEFORE THE SHIFT TO MORE WSW...THERE
WILL BE A FEW SYSTEMS MOVING EAST THRU THE FLOW. THESE LOWS WILL
PASS WAY TO OUR NORTH. LOW-LEVEL MODEL RH READINGS(W-NW DOWNSLOPE)
PUT AIRMASS TOO DRY SUNDAY NIGHT INTO FRIDAY TO OTHER THAN PUT SOME
MID LEVEL CLOUDS OVER THE REGION.

THE ARRIVAL OF THE CUTOFF SYSTEM BY THE END OF THE WEEK WILL GIVE
THE AREA THE NEXT BEST CHANCE FOR PRECIPITATION. HIGH PRESSURE OVER
THE SOUTHEAST PORTION OF THE COUNTRY...COMBINED WITH SURFACE LOW OUT
AHEAD OF THE UPPER SYSTEM OVER SW TEXAS...WILL ALLOW FOR LOW LEVEL
MOISTURE TO FUNNEL INTO THE SOUTHERN/CENTRAL PLAINS. THE POSITIONING
OF THE LOW WILL BE KEY TO HOW MUCH PRECIP THE REGION WILL RECEIVE.
MODEL TREND IS FOR NOW TO KEEP SYSTEM TOO FAR SOUTH KEEPING BULK OF
MOISTURE AWAY FROM REGION. THE RESULT WILL BE SLIGHT CHANCE FOR -SW.
0-DEGREE ISOTHERM WILL MEANDER OVER THE REGION DURING THIS
TIMEFRAME...SO AREA COULD SEE A -RW MIX/CHANCE ESPECIALLY SE ZONES
CLOSEST TO WARMER AIRMASS. LIGHT QPF POTENTIAL WILL ONLY GIVE AREA
LIGHT SNOWFALL POTENTIAL AT THIS TIME...BUT COULD CHANGE AS WEEK
PROGRESSES AND MODELS SHIFT POSITION OF UPPER LOW.

FOR TEMPS...ABOVE NORMAL HIGHS IN THE MID 40S TO MID 50S RANGE WILL
PERSIST FOR ALL AREAS...WITH 30S ON SATURDAY AS REGION JUST NORTH OF
WARMER AIR WITH SYSTEM TO THE SOUTH. OVERNIGHT LOWS WILL RANGE
MAINLY IN THE 20S...COLDEST OVER EASTERN COLORADO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 930 PM MST SAT DEC 19 2015

FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
WINDS AT KGLD FROM THE SOUTHWEST NEAR 12KTS FROM TAF ISSUANCE
THROUGH 08Z THEN A GRADUAL VEERING TO THE WEST-NORTHWEST BY
15Z...NORTHWEST FROM 20Z THROUGH THE REST OF THE TAF PERIOD.
SPEEDS GENERALLY UNDER 10KTS. FOR KMCK...LIGHT AND VARIABLE WINDS
FROM TAF ISSUANCE THROUGH 17Z THEN NORTHWEST 6-10KTS FROM 18Z
THROUGH THE REST OF THE TAF PERIOD. MID AND MOSTLY HIGH CLOUDS
EXPECTED THROUGH THE PERIOD. HAVE A BIT OF CONCERN IN THE 22Z-04Z
TIMEFRAME AT BOTH TERMINALS. ITS DURING THIS TIME THAT AN UPPER
TROUGH OF LOW PRESSURE MOVES ACROSS THE AREA. NAM MOISTURE CROSS
SECTIONS SHOW LOW LEVEL MOISTURE INCREASING WITH THE TROUGH
PASSAGE POSSIBLY CREATING SOME MVFR CLOUDINESS AND POSSIBLY SOME
LIGHT RAIN SHOWERS. HRRR MODEL ALSO SHOWING SOME LIGHT PRECIP AS
WELL. WILL HOLD OFF ON INTRODUCING ANY PRECIP MENTION AS CURRENT
FORECAST IS DRY. WILL ALSO HOLD OFF ANY SUB VFR CLOUDINESS AS THE
NAM APPEARS TO BE THE ONLY MODEL SHOWING MVFR CIGS AT PRESENT
TIME.

&&

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

$$

SHORT TERM...RRH
LONG TERM...JN
AVIATION...99




AREA FORECAST DISCUSSION

NWS JACKSON KY

 1234 PM EST SUN DEC 20 2015

.UPDATE...
ISSUED AT 1102 AM EST SUN DEC 20 2015

TEMPERATURES HAVE BEGUN TO RISE ACROSS THE AREA THIS
MORNING...THOUGH SLOWLY DUE TO INCREASING UPPER LEVEL CLOUD
COVER. HAVE ADJUSTED TEMPS AND CLOUD COVER WITH THIS UPDATE.

UPDATE ISSUED AT 640 AM EST SUN DEC 20 2015

A BAND OF CIRRUS SLIPPED OVER THE CWA DURING THE PAST COUPLE OF
HOURS AND THEY LIKELY HELPED TO SLOW THE TEMPERATURE DROP IN THE
VALLEYS AND ELSEWHERE. ACCORDINGLY...HAVE TWEAKED THE SKY COVER
AND T/TD GRIDS PER THE LATEST OBS AND TRENDS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM EST SUN DEC 20 2015

07Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO SLIP OFF TO THE
EAST. BEFORE IT GOES IT IS GIVING THE AREA ONE MORE CHILLY NIGHT
ALONG WITH A DECENT SIZED RIDGE TO VALLEY TEMPERATURE SPLIT. CLEAR
SKIES BENEATH THE HIGH ALONG WITH LIGHT SFC WINDS AND A DRY AIR
MASS HAS RESULTED IN VALLEY TEMPERATURES HAVEN FALLEN TO NEAR 20
DEGREES. MEANWHILE...THE RIDGES ARE CLOSER TO FREEZING WHILE
DEWPOINTS THROUGHOUT THE AREA ARE CROWDING THE 20 DEGREE MARKER.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT RIDGE CROSSING THE
TENNESSEE VALLEY WITH HEIGHT RISES ON TAP FOR KENTUCKY TODAY. A
SHORTWAVE TROUGH WILL THEN MOVE INTO THE SOUTHERN PLAINS TONIGHT
PLACING OUR AREA DOWNSTREAM IN BROAD SOUTHWEST FLOW. SOME WEAK
ENERGY WAVES WILL PASS THROUGH EASTERN KENTUCKY BY MONDAY MORNING
WITH THE MAIN WAVE TAKING A TRACK TO THE NORTHWEST OF KENTUCKY.
SOUTHWEST FLOW WILL CONTINUE INTO MONDAY EVENING AS ANOTHER
TROUGH AND ENERGY BATCH HEAD FOR THE STATE FROM THE WEST. GIVEN
THE GENERAL MODEL AGREEMENT HAVE AGAIN FAVORED THE HIGHER
RESOLUTION HRRR AND NAM12 FOR WEATHER DETAILS.

SENSIBLE WEATHER WILL FEATURE ANOTHER CHILLY START THIS MORNING...
BUT PLENTY OF SUNSHINE WILL OVERCOME THAT YIELDING AFTERNOON
TEMPERATURES IN THE 50 TO 55 DEGREE RANGE. HIGH CLOUDS WILL ARRIVE
AND THICKEN WITH TIME THIS AFTERNOON INTO THE NIGHT AHEAD OF A
QUICK MOVING COLD FRONT INBOUND FROM THE WEST. THIS FRONT WILL
BRING ANOTHER ROUND OF SHOWERS TO THE CWA FOR MONDAY...THOUGH THE
BEST MOISTURE AND HIGHEST PCPN CHANCES SPLIT THE AREA TO THE
NORTH AND SOUTH. WHILE SOME EASTERN VALLEYS WILL FALL BELOW
FREEZING TONIGHT...EXPECT THE FRONT/S APPROACH TO STIR THE AIR
ENOUGH TO KEEP THEM FROM BEING THAT COLD WHEN THE FIRST RAIN
CHANCES ARRIVE...SO HAVE LEFT ANY MIX CHANCES OF PCPN OUT OF THE
FORECAST FOR NOW. THE FRONT WILL THEN STALL OVERHEAD THAT WITH
THE NEXT SURGE OF MOISTURE LIKELY RIDING NORTH INTO THIS PART OF
THE STATE LATER MONDAY NIGHT.

FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS THROUGH TONIGHT FOLLOWED BY THE SUPERBLEND INTO
MONDAY EVENING. DID AGAIN MAKE SOME MORE SIGNIFICANT ADJUSTMENTS
TO THE LOWS TONIGHT...ESPECIALLY IN THE EASTERN VALLEYS DUE TO
THE ANTICIPATION OF AN EARLY TEMPERATURE DROP OFF THIS EVENING
FOLLOWED BY RISING TEMPS TOWARD DAWN FOR THE MOST SHELTERED
LOCATIONS. AS FOR POPS...ENDED UP ON THE HIGHER SIDE OF ALL MOS
FOR MONDAY...BUT CLOSEST TO THE MAV NUMBERS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EST SUN DEC 20 2015

VERY MILD AND POTENTIALLY RECORD BREAKING WARMTH WILL REMAIN THE
MAIN HEADLINE AS WE HEAD THROUGH CHRISTMAS WEEK.  IN ADDITION TO THE
WARMTH...PLENTY OF CHANCES FOR RAIN WILL BE SEEN.

STRONG RIDGING WILL BE IN PLACE ACROSS THE EASTERN CONUS THROUGH ALL
OF CHRISTMAS WEEK. STARTING OFF TUESDAY NIGHT...A POTENT SHORTWAVE
WILL MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ALONG A STALLED OUT
COLD FRONT. THIS WILL BRING INCREASING RAIN CHANCES THROUGH THE
OVERNIGHT HOURS. FORCING WITH THIS WAVE WILL EXIT NORTH EARLY
TUESDAY MORNING...WITH SUBSIDENCE BUILDING IN BEHIND THE DEPARTING
WAVE ON TUESDAY. TEMPERATURES WILL CLIMB INTO THE 60S ON TUESDAY
ALTHOUGH WE`LL HAVE A TOUGH TIME GETTING RID OF THE CLOUDS.  A
SECONDARY WAVE WILL LIFT NORTH TUESDAY NIGHT AND BRING ANOTHER ROUND
OF RAIN SHOWERS TO EASTERN KENTUCKY. STILL SOME UNCERTAINTY ON THE
EXTENT OF RAIN CHANCES AND HOW SOUTHEAST DOWNSLOPING FLOW IMPACTS
OUR RAIN CHANCES. HOWEVER...WILL GO WITH HIGHEST POPS IN THE
WEST...TO LOWER POPS IN THE EAST.

ON WEDNESDAY...WE MAY SEE ANOTHER LULL AS SUBSIDENCE SPREADS BACK IN
BEHIND THE DEPARTING WAVE.  WITH EVEN WARMER BOUNDARY LAYER
CONDITIONS IN PLACE...WE COULD BE EASILY PUSHING 70...WITH GUIDANCE
SUGGESTING WIDESPREAD LOWER 70S.  THIS WOULD EXCEED OUR RECORDS FOR
WEDNESDAY BY 5 TO 8 DEGREES. FINALLY...A COLD FRONT WILL WORK EAST
ACROSS THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING...BRINGING ANOTHER SURGE OF RAIN.  THIS TIME AROUND...THE
FRONT SHOULD MOVE ON EAST...BRINGING A TEMPORARY END TO THE RAIN
CHANCES.  HIGH PRESSURE SHOULD KEEP THE WEATHER DRY FROM LATE
THURSDAY MORNING THROUGH CHRISTMAS MORNING.  HOWEVER...MODELS ARE
TRENDING FASTER WITH BRINGING RAIN CHANCES. IF THIS OCCURS...WE
WILL CERTAINLY BRING POPS BACK INTO THE AREA ON CHRISTMAS AS A
WARM FRONT QUICKLY SURGES BACK TO THE NORTH. THIS WILL NOT ONLY
MEAN A WARMER CHRISTMAS...BUT A WETTER ONE AS WELL. AS WE HEAD
INTO THE WEEKEND...MODELS ARE HAVING A TOUGH TIME ON HOW THINGS
EVOLVE...BUT CERTAINLY COULD BE SOME WET WEATHER AT SOME POINT
OVER THE WEEKEND AS A DEEP SYSTEM ORGANIZES SOMEWHERE OVER THE
CENTRAL OR EASTERN US. FOR THIS REASON WILL KEEP SOME CHANCE POPS
IN THE FORECAST THROUGH THE WEEKEND. IT DOES LOOK LIKE WE SHOULD
REMAIN MILD THROUGH THE WEEKEND...WITH PERHAPS A BRIEF COOL DOWN
AS WE HEAD INTO THE FOLLOW WEEK. HOWEVER...THERE IS MUCH
UNCERTAINTY IN THE FORECAST BEYOND CHRISTMAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM EST SUN DEC 20 2015

HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE REGION THROUGH
MUCH OF THE TAF PERIOD PROVIDING VFR CONDITIONS UNDER THICKENING
HIGH CLOUDS. AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID
LEVEL CLOUD TOWARD DAWN ON MONDAY. BY 14Z ON MONDAY...SOME
LOCATIONS WILL SEE SHOWERS MOVING INTO THE AREA WITH SOME MVFR
CIGS DEVELOPING TOWARDS THE END OF THE TAF PERIOD. WINDS WILL BE
LIGHT AND VARIABLE THROUGH THE BULK OF THE PERIOD BEFORE
INCREASING AND GUSTING UP TO 20 KNOTS OUT OF THE SOUTH BY LATE
MONDAY MORNING.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SHALLENBERGER
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...SHALLENBERGER




AREA FORECAST DISCUSSION

NWS JACKSON KY

 1103 AM EST SUN DEC 20 2015

.UPDATE...
ISSUED AT 1102 AM EST SUN DEC 20 2015

TEMPERATURES HAVE BEGUN TO RISE ACROSS THE AREA THIS
MORNING...THOUGH SLOWLY DUE TO INCREASING UPPER LEVEL CLOUD
COVER. HAVE ADJUSTED TEMPS AND CLOUD COVER WITH THIS UPDATE.

UPDATE ISSUED AT 640 AM EST SUN DEC 20 2015

A BAND OF CIRRUS SLIPPED OVER THE CWA DURING THE PAST COUPLE OF
HOURS AND THEY LIKELY HELPED TO SLOW THE TEMPERATURE DROP IN THE
VALLEYS AND ELSEWHERE. ACCORDINGLY...HAVE TWEAKED THE SKY COVER
AND T/TD GRIDS PER THE LATEST OBS AND TRENDS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM EST SUN DEC 20 2015

07Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO SLIP OFF TO THE
EAST. BEFORE IT GOES IT IS GIVING THE AREA ONE MORE CHILLY NIGHT
ALONG WITH A DECENT SIZED RIDGE TO VALLEY TEMPERATURE SPLIT. CLEAR
SKIES BENEATH THE HIGH ALONG WITH LIGHT SFC WINDS AND A DRY AIR
MASS HAS RESULTED IN VALLEY TEMPERATURES HAVEN FALLEN TO NEAR 20
DEGREES. MEANWHILE...THE RIDGES ARE CLOSER TO FREEZING WHILE
DEWPOINTS THROUGHOUT THE AREA ARE CROWDING THE 20 DEGREE MARKER.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT RIDGE CROSSING THE
TENNESSEE VALLEY WITH HEIGHT RISES ON TAP FOR KENTUCKY TODAY. A
SHORTWAVE TROUGH WILL THEN MOVE INTO THE SOUTHERN PLAINS TONIGHT
PLACING OUR AREA DOWNSTREAM IN BROAD SOUTHWEST FLOW. SOME WEAK
ENERGY WAVES WILL PASS THROUGH EASTERN KENTUCKY BY MONDAY MORNING
WITH THE MAIN WAVE TAKING A TRACK TO THE NORTHWEST OF KENTUCKY.
SOUTHWEST FLOW WILL CONTINUE INTO MONDAY EVENING AS ANOTHER
TROUGH AND ENERGY BATCH HEAD FOR THE STATE FROM THE WEST. GIVEN
THE GENERAL MODEL AGREEMENT HAVE AGAIN FAVORED THE HIGHER
RESOLUTION HRRR AND NAM12 FOR WEATHER DETAILS.

SENSIBLE WEATHER WILL FEATURE ANOTHER CHILLY START THIS MORNING...
BUT PLENTY OF SUNSHINE WILL OVERCOME THAT YIELDING AFTERNOON
TEMPERATURES IN THE 50 TO 55 DEGREE RANGE. HIGH CLOUDS WILL ARRIVE
AND THICKEN WITH TIME THIS AFTERNOON INTO THE NIGHT AHEAD OF A
QUICK MOVING COLD FRONT INBOUND FROM THE WEST. THIS FRONT WILL
BRING ANOTHER ROUND OF SHOWERS TO THE CWA FOR MONDAY...THOUGH THE
BEST MOISTURE AND HIGHEST PCPN CHANCES SPLIT THE AREA TO THE
NORTH AND SOUTH. WHILE SOME EASTERN VALLEYS WILL FALL BELOW
FREEZING TONIGHT...EXPECT THE FRONT/S APPROACH TO STIR THE AIR
ENOUGH TO KEEP THEM FROM BEING THAT COLD WHEN THE FIRST RAIN
CHANCES ARRIVE...SO HAVE LEFT ANY MIX CHANCES OF PCPN OUT OF THE
FORECAST FOR NOW. THE FRONT WILL THEN STALL OVERHEAD THAT WITH
THE NEXT SURGE OF MOISTURE LIKELY RIDING NORTH INTO THIS PART OF
THE STATE LATER MONDAY NIGHT.

FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS THROUGH TONIGHT FOLLOWED BY THE SUPERBLEND INTO
MONDAY EVENING. DID AGAIN MAKE SOME MORE SIGNIFICANT ADJUSTMENTS
TO THE LOWS TONIGHT...ESPECIALLY IN THE EASTERN VALLEYS DUE TO
THE ANTICIPATION OF AN EARLY TEMPERATURE DROP OFF THIS EVENING
FOLLOWED BY RISING TEMPS TOWARD DAWN FOR THE MOST SHELTERED
LOCATIONS. AS FOR POPS...ENDED UP ON THE HIGHER SIDE OF ALL MOS
FOR MONDAY...BUT CLOSEST TO THE MAV NUMBERS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EST SUN DEC 20 2015

VERY MILD AND POTENTIALLY RECORD BREAKING WARMTH WILL REMAIN THE
MAIN HEADLINE AS WE HEAD THROUGH CHRISTMAS WEEK.  IN ADDITION TO THE
WARMTH...PLENTY OF CHANCES FOR RAIN WILL BE SEEN.

STRONG RIDGING WILL BE IN PLACE ACROSS THE EASTERN CONUS THROUGH ALL
OF CHRISTMAS WEEK. STARTING OFF TUESDAY NIGHT...A POTENT SHORTWAVE
WILL MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ALONG A STALLED OUT
COLD FRONT. THIS WILL BRING INCREASING RAIN CHANCES THROUGH THE
OVERNIGHT HOURS. FORCING WITH THIS WAVE WILL EXIT NORTH EARLY
TUESDAY MORNING...WITH SUBSIDENCE BUILDING IN BEHIND THE DEPARTING
WAVE ON TUESDAY. TEMPERATURES WILL CLIMB INTO THE 60S ON TUESDAY
ALTHOUGH WE`LL HAVE A TOUGH TIME GETTING RID OF THE CLOUDS.  A
SECONDARY WAVE WILL LIFT NORTH TUESDAY NIGHT AND BRING ANOTHER ROUND
OF RAIN SHOWERS TO EASTERN KENTUCKY. STILL SOME UNCERTAINTY ON THE
EXTENT OF RAIN CHANCES AND HOW SOUTHEAST DOWNSLOPING FLOW IMPACTS
OUR RAIN CHANCES. HOWEVER...WILL GO WITH HIGHEST POPS IN THE
WEST...TO LOWER POPS IN THE EAST.

ON WEDNESDAY...WE MAY SEE ANOTHER LULL AS SUBSIDENCE SPREADS BACK IN
BEHIND THE DEPARTING WAVE.  WITH EVEN WARMER BOUNDARY LAYER
CONDITIONS IN PLACE...WE COULD BE EASILY PUSHING 70...WITH GUIDANCE
SUGGESTING WIDESPREAD LOWER 70S.  THIS WOULD EXCEED OUR RECORDS FOR
WEDNESDAY BY 5 TO 8 DEGREES. FINALLY...A COLD FRONT WILL WORK EAST
ACROSS THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING...BRINGING ANOTHER SURGE OF RAIN.  THIS TIME AROUND...THE
FRONT SHOULD MOVE ON EAST...BRINGING A TEMPORARY END TO THE RAIN
CHANCES.  HIGH PRESSURE SHOULD KEEP THE WEATHER DRY FROM LATE
THURSDAY MORNING THROUGH CHRISTMAS MORNING.  HOWEVER...MODELS ARE
TRENDING FASTER WITH BRINGING RAIN CHANCES. IF THIS OCCURS...WE
WILL CERTAINLY BRING POPS BACK INTO THE AREA ON CHRISTMAS AS A
WARM FRONT QUICKLY SURGES BACK TO THE NORTH. THIS WILL NOT ONLY
MEAN A WARMER CHRISTMAS...BUT A WETTER ONE AS WELL. AS WE HEAD
INTO THE WEEKEND...MODELS ARE HAVING A TOUGH TIME ON HOW THINGS
EVOLVE...BUT CERTAINLY COULD BE SOME WET WEATHER AT SOME POINT
OVER THE WEEKEND AS A DEEP SYSTEM ORGANIZES SOMEWHERE OVER THE
CENTRAL OR EASTERN US. FOR THIS REASON WILL KEEP SOME CHANCE POPS
IN THE FORECAST THROUGH THE WEEKEND. IT DOES LOOK LIKE WE SHOULD
REMAIN MILD THROUGH THE WEEKEND...WITH PERHAPS A BRIEF COOL DOWN
AS WE HEAD INTO THE FOLLOW WEEK. HOWEVER...THERE IS MUCH
UNCERTAINTY IN THE FORECAST BEYOND CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 700 AM EST SUN DEC 20 2015

HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE REGION THROUGH THE
TAF PERIOD PROVIDING VFR CONDITIONS UNDER THICKENING HIGH CLOUDS.
AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID LEVEL
CLOUD TOWARD DAWN ON MONDAY. WINDS WILL BE LIGHT AND VARIABLE
THROUGH THE BULK OF THE PERIOD WITH SOME STIRRING FROM THE SOUTH
ANTICIPATED BY 12Z MONDAY.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SHALLENBERGER
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF




AREA FORECAST DISCUSSION...UPDATED

NWS JACKSON KY

 700 AM EST SUN DEC 20 2015

.UPDATE...
ISSUED AT 640 AM EST SUN DEC 20 2015

A BAND OF CIRRUS SLIPPED OVER THE CWA DURING THE PAST COUPLE OF
HOURS AND THEY LIKELY HELPED TO SLOW THE TEMPERATURE DROP IN THE
VALLEYS AND ELSEWHERE. ACCORDINGLY...HAVE TWEAKED THE SKY COVER
AND T/TD GRIDS PER THE LATEST OBS AND TRENDS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM EST SUN DEC 20 2015

07Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO SLIP OFF TO THE
EAST. BEFORE IT GOES IT IS GIVING THE AREA ONE MORE CHILLY NIGHT
ALONG WITH A DECENT SIZED RIDGE TO VALLEY TEMPERATURE SPLIT. CLEAR
SKIES BENEATH THE HIGH ALONG WITH LIGHT SFC WINDS AND A DRY AIR
MASS HAS RESULTED IN VALLEY TEMPERATURES HAVEN FALLEN TO NEAR 20
DEGREES. MEANWHILE...THE RIDGES ARE CLOSER TO FREEZING WHILE
DEWPOINTS THROUGHOUT THE AREA ARE CROWDING THE 20 DEGREE MARKER.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT RIDGE CROSSING THE
TENNESSEE VALLEY WITH HEIGHT RISES ON TAP FOR KENTUCKY TODAY. A
SHORTWAVE TROUGH WILL THEN MOVE INTO THE SOUTHERN PLAINS TONIGHT
PLACING OUR AREA DOWNSTREAM IN BROAD SOUTHWEST FLOW. SOME WEAK
ENERGY WAVES WILL PASS THROUGH EASTERN KENTUCKY BY MONDAY MORNING
WITH THE MAIN WAVE TAKING A TRACK TO THE NORTHWEST OF KENTUCKY.
SOUTHWEST FLOW WILL CONTINUE INTO MONDAY EVENING AS ANOTHER
TROUGH AND ENERGY BATCH HEAD FOR THE STATE FROM THE WEST. GIVEN
THE GENERAL MODEL AGREEMENT HAVE AGAIN FAVORED THE HIGHER
RESOLUTION HRRR AND NAM12 FOR WEATHER DETAILS.

SENSIBLE WEATHER WILL FEATURE ANOTHER CHILLY START THIS MORNING...
BUT PLENTY OF SUNSHINE WILL OVERCOME THAT YIELDING AFTERNOON
TEMPERATURES IN THE 50 TO 55 DEGREE RANGE. HIGH CLOUDS WILL ARRIVE
AND THICKEN WITH TIME THIS AFTERNOON INTO THE NIGHT AHEAD OF A
QUICK MOVING COLD FRONT INBOUND FROM THE WEST. THIS FRONT WILL
BRING ANOTHER ROUND OF SHOWERS TO THE CWA FOR MONDAY...THOUGH THE
BEST MOISTURE AND HIGHEST PCPN CHANCES SPLIT THE AREA TO THE
NORTH AND SOUTH. WHILE SOME EASTERN VALLEYS WILL FALL BELOW
FREEZING TONIGHT...EXPECT THE FRONT/S APPROACH TO STIR THE AIR
ENOUGH TO KEEP THEM FROM BEING THAT COLD WHEN THE FIRST RAIN
CHANCES ARRIVE...SO HAVE LEFT ANY MIX CHANCES OF PCPN OUT OF THE
FORECAST FOR NOW. THE FRONT WILL THEN STALL OVERHEAD THAT WITH
THE NEXT SURGE OF MOISTURE LIKELY RIDING NORTH INTO THIS PART OF
THE STATE LATER MONDAY NIGHT.

FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS THROUGH TONIGHT FOLLOWED BY THE SUPERBLEND INTO
MONDAY EVENING. DID AGAIN MAKE SOME MORE SIGNIFICANT ADJUSTMENTS
TO THE LOWS TONIGHT...ESPECIALLY IN THE EASTERN VALLEYS DUE TO
THE ANTICIPATION OF AN EARLY TEMPERATURE DROP OFF THIS EVENING
FOLLOWED BY RISING TEMPS TOWARD DAWN FOR THE MOST SHELTERED
LOCATIONS. AS FOR POPS...ENDED UP ON THE HIGHER SIDE OF ALL MOS
FOR MONDAY...BUT CLOSEST TO THE MAV NUMBERS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EST SUN DEC 20 2015

VERY MILD AND POTENTIALLY RECORD BREAKING WARMTH WILL REMAIN THE
MAIN HEADLINE AS WE HEAD THROUGH CHRISTMAS WEEK.  IN ADDITION TO THE
WARMTH...PLENTY OF CHANCES FOR RAIN WILL BE SEEN.

STRONG RIDGING WILL BE IN PLACE ACROSS THE EASTERN CONUS THROUGH ALL
OF CHRISTMAS WEEK. STARTING OFF TUESDAY NIGHT...A POTENT SHORTWAVE
WILL MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ALONG A STALLED OUT
COLD FRONT. THIS WILL BRING INCREASING RAIN CHANCES THROUGH THE
OVERNIGHT HOURS. FORCING WITH THIS WAVE WILL EXIT NORTH EARLY
TUESDAY MORNING...WITH SUBSIDENCE BUILDING IN BEHIND THE DEPARTING
WAVE ON TUESDAY. TEMPERATURES WILL CLIMB INTO THE 60S ON TUESDAY
ALTHOUGH WE`LL HAVE A TOUGH TIME GETTING RID OF THE CLOUDS.  A
SECONDARY WAVE WILL LIFT NORTH TUESDAY NIGHT AND BRING ANOTHER ROUND
OF RAIN SHOWERS TO EASTERN KENTUCKY. STILL SOME UNCERTAINTY ON THE
EXTENT OF RAIN CHANCES AND HOW SOUTHEAST DOWNSLOPING FLOW IMPACTS
OUR RAIN CHANCES. HOWEVER...WILL GO WITH HIGHEST POPS IN THE
WEST...TO LOWER POPS IN THE EAST.

ON WEDNESDAY...WE MAY SEE ANOTHER LULL AS SUBSIDENCE SPREADS BACK IN
BEHIND THE DEPARTING WAVE.  WITH EVEN WARMER BOUNDARY LAYER
CONDITIONS IN PLACE...WE COULD BE EASILY PUSHING 70...WITH GUIDANCE
SUGGESTING WIDESPREAD LOWER 70S.  THIS WOULD EXCEED OUR RECORDS FOR
WEDNESDAY BY 5 TO 8 DEGREES. FINALLY...A COLD FRONT WILL WORK EAST
ACROSS THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING...BRINGING ANOTHER SURGE OF RAIN.  THIS TIME AROUND...THE
FRONT SHOULD MOVE ON EAST...BRINGING A TEMPORARY END TO THE RAIN
CHANCES.  HIGH PRESSURE SHOULD KEEP THE WEATHER DRY FROM LATE
THURSDAY MORNING THROUGH CHRISTMAS MORNING.  HOWEVER...MODELS ARE
TRENDING FASTER WITH BRINGING RAIN CHANCES. IF THIS OCCURS...WE
WILL CERTAINLY BRING POPS BACK INTO THE AREA ON CHRISTMAS AS A
WARM FRONT QUICKLY SURGES BACK TO THE NORTH. THIS WILL NOT ONLY
MEAN A WARMER CHRISTMAS...BUT A WETTER ONE AS WELL. AS WE HEAD
INTO THE WEEKEND...MODELS ARE HAVING A TOUGH TIME ON HOW THINGS
EVOLVE...BUT CERTAINLY COULD BE SOME WET WEATHER AT SOME POINT
OVER THE WEEKEND AS A DEEP SYSTEM ORGANIZES SOMEWHERE OVER THE
CENTRAL OR EASTERN US. FOR THIS REASON WILL KEEP SOME CHANCE POPS
IN THE FORECAST THROUGH THE WEEKEND. IT DOES LOOK LIKE WE SHOULD
REMAIN MILD THROUGH THE WEEKEND...WITH PERHAPS A BRIEF COOL DOWN
AS WE HEAD INTO THE FOLLOW WEEK. HOWEVER...THERE IS MUCH
UNCERTAINTY IN THE FORECAST BEYOND CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 700 AM EST SUN DEC 20 2015

HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE REGION THROUGH THE
TAF PERIOD PROVIDING VFR CONDITIONS UNDER THICKENING HIGH CLOUDS.
AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID LEVEL
CLOUD TOWARD DAWN ON MONDAY. WINDS WILL BE LIGHT AND VARIABLE
THROUGH THE BULK OF THE PERIOD WITH SOME STIRRING FROM THE SOUTH
ANTICIPATED BY 12Z MONDAY.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF



AREA FORECAST DISCUSSION

NWS JACKSON KY

 345 AM EST SUN DEC 20 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM EST SUN DEC 20 2015

07Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO SLIP OFF TO THE
EAST. BEFORE IT GOES IT IS GIVING THE AREA ONE MORE CHILLY NIGHT
ALONG WITH A DECENT SIZED RIDGE TO VALLEY TEMPERATURE SPLIT. CLEAR
SKIES BENEATH THE HIGH ALONG WITH LIGHT SFC WINDS AND A DRY AIR
MASS HAS RESULTED IN VALLEY TEMPERATURES HAVEN FALLEN TO NEAR 20
DEGREES. MEANWHILE...THE RIDGES ARE CLOSER TO FREEZING WHILE
DEWPOINTS THROUGHOUT THE AREA ARE CROWDING THE 20 DEGREE MARKER.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT RIDGE CROSSING THE
TENNESSEE VALLEY WITH HEIGHT RISES ON TAP FOR KENTUCKY TODAY. A
SHORTWAVE TROUGH WILL THEN MOVE INTO THE SOUTHERN PLAINS TONIGHT
PLACING OUR AREA DOWNSTREAM IN BROAD SOUTHWEST FLOW. SOME WEAK
ENERGY WAVES WILL PASS THROUGH EASTERN KENTUCKY BY MONDAY MORNING
WITH THE MAIN WAVE TAKING A TRACK TO THE NORTHWEST OF KENTUCKY.
SOUTHWEST FLOW WILL CONTINUE INTO MONDAY EVENING AS ANOTHER
TROUGH AND ENERGY BATCH HEAD FOR THE STATE FROM THE WEST. GIVEN
THE GENERAL MODEL AGREEMENT HAVE AGAIN FAVORED THE HIGHER
RESOLUTION HRRR AND NAM12 FOR WEATHER DETAILS.

SENSIBLE WEATHER WILL FEATURE ANOTHER CHILLY START THIS MORNING...
BUT PLENTY OF SUNSHINE WILL OVERCOME THAT YIELDING AFTERNOON
TEMPERATURES IN THE 50 TO 55 DEGREE RANGE. HIGH CLOUDS WILL ARRIVE
AND THICKEN WITH TIME THIS AFTERNOON INTO THE NIGHT AHEAD OF A
QUICK MOVING COLD FRONT INBOUND FROM THE WEST. THIS FRONT WILL
BRING ANOTHER ROUND OF SHOWERS TO THE CWA FOR MONDAY...THOUGH THE
BEST MOISTURE AND HIGHEST PCPN CHANCES SPLIT THE AREA TO THE
NORTH AND SOUTH. WHILE SOME EASTERN VALLEYS WILL FALL BELOW
FREEZING TONIGHT...EXPECT THE FRONT/S APPROACH TO STIR THE AIR
ENOUGH TO KEEP THEM FROM BEING THAT COLD WHEN THE FIRST RAIN
CHANCES ARRIVE...SO HAVE LEFT ANY MIX CHANCES OF PCPN OUT OF THE
FORECAST FOR NOW. THE FRONT WILL THEN STALL OVERHEAD THAT WITH
THE NEXT SURGE OF MOISTURE LIKELY RIDING NORTH INTO THIS PART OF
THE STATE LATER MONDAY NIGHT.

FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS THROUGH TONIGHT FOLLOWED BY THE SUPERBLEND INTO
MONDAY EVENING. DID AGAIN MAKE SOME MORE SIGNIFICANT ADJUSTMENTS
TO THE LOWS TONIGHT...ESPECIALLY IN THE EASTERN VALLEYS DUE TO
THE ANTICIPATION OF AN EARLY TEMPERATURE DROP OFF THIS EVENING
FOLLOWED BY RISING TEMPS TOWARD DAWN FOR THE MOST SHELTERED
LOCATIONS. AS FOR POPS...ENDED UP ON THE HIGHER SIDE OF ALL MOS
FOR MONDAY...BUT CLOSEST TO THE MAV NUMBERS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EST SUN DEC 20 2015

VERY MILD AND POTENTIALLY RECORD BREAKING WARMTH WILL REMAIN THE
MAIN HEADLINE AS WE HEAD THROUGH CHRISTMAS WEEK.  IN ADDITION TO THE
WARMTH...PLENTY OF CHANCES FOR RAIN WILL BE SEEN.

STRONG RIDGING WILL BE IN PLACE ACROSS THE EASTERN CONUS THROUGH ALL
OF CHRISTMAS WEEK. STARTING OFF TUESDAY NIGHT...A POTENT SHORTWAVE
WILL MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ALONG A STALLED OUT
COLD FRONT. THIS WILL BRING INCREASING RAIN CHANCES THROUGH THE
OVERNIGHT HOURS. FORCING WITH THIS WAVE WILL EXIT NORTH EARLY
TUESDAY MORNING...WITH SUBSIDENCE BUILDING IN BEHIND THE DEPARTING
WAVE ON TUESDAY. TEMPERATURES WILL CLIMB INTO THE 60S ON TUESDAY
ALTHOUGH WE`LL HAVE A TOUGH TIME GETTING RID OF THE CLOUDS.  A
SECONDARY WAVE WILL LIFT NORTH TUESDAY NIGHT AND BRING ANOTHER ROUND
OF RAIN SHOWERS TO EASTERN KENTUCKY. STILL SOME UNCERTAINTY ON THE
EXTENT OF RAIN CHANCES AND HOW SOUTHEAST DOWNSLOPING FLOW IMPACTS
OUR RAIN CHANCES. HOWEVER...WILL GO WITH HIGHEST POPS IN THE
WEST...TO LOWER POPS IN THE EAST.

ON WEDNESDAY...WE MAY SEE ANOTHER LULL AS SUBSIDENCE SPREADS BACK IN
BEHIND THE DEPARTING WAVE.  WITH EVEN WARMER BOUNDARY LAYER
CONDITIONS IN PLACE...WE COULD BE EASILY PUSHING 70...WITH GUIDANCE
SUGGESTING WIDESPREAD LOWER 70S.  THIS WOULD EXCEED OUR RECORDS FOR
WEDNESDAY BY 5 TO 8 DEGREES. FINALLY...A COLD FRONT WILL WORK EAST
ACROSS THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING...BRINGING ANOTHER SURGE OF RAIN.  THIS TIME AROUND...THE
FRONT SHOULD MOVE ON EAST...BRINGING A TEMPORARY END TO THE RAIN
CHANCES.  HIGH PRESSURE SHOULD KEEP THE WEATHER DRY FROM LATE
THURSDAY MORNING THROUGH CHRISTMAS MORNING.  HOWEVER...MODELS ARE
TRENDING FASTER WITH BRINGING RAIN CHANCES. IF THIS OCCURS...WE
WILL CERTAINLY BRING POPS BACK INTO THE AREA ON CHRISTMAS AS A
WARM FRONT QUICKLY SURGES BACK TO THE NORTH. THIS WILL NOT ONLY
MEAN A WARMER CHRISTMAS...BUT A WETTER ONE AS WELL. AS WE HEAD
INTO THE WEEKEND...MODELS ARE HAVING A TOUGH TIME ON HOW THINGS
EVOLVE...BUT CERTAINLY COULD BE SOME WET WEATHER AT SOME POINT
OVER THE WEEKEND AS A DEEP SYSTEM ORGANIZES SOMEWHERE OVER THE
CENTRAL OR EASTERN US. FOR THIS REASON WILL KEEP SOME CHANCE POPS
IN THE FORECAST THROUGH THE WEEKEND. IT DOES LOOK LIKE WE SHOULD
REMAIN MILD THROUGH THE WEEKEND...WITH PERHAPS A BRIEF COOL DOWN
AS WE HEAD INTO THE FOLLOW WEEK. HOWEVER...THERE IS MUCH
UNCERTAINTY IN THE FORECAST BEYOND CHRISTMAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1250 AM EST SUN DEC 20 2015

HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE REGION THROUGH THE
TAF PERIOD PROVIDING VFR CONDITIONS UNDER MOSTLY CLEAR SKIES. IN
ADDITION...WINDS WILL BE LIGHT AND VARIABLE THROUGH SUNDAY NIGHT.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF



AREA FORECAST DISCUSSION

NWS CARIBOU ME

 1214 AM EST SUN DEC 20 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD TONIGHT INTO SUNDAY. A WARM FRONT WILL
CROSS THE REGION MONDAY. A WEAK AREA OF LOW PRESSURE WILL MOVE
NORTH OF THE STATE MONDAY NIGHT INTO TUESDAY.

&&

.NEAR TERM /THROUGH TODAY/...
UPDATE: LATEST RADAR REFLECTIVITY SHOWS WHAT`S LEFT OF THE SNOW
BANDS ARE WEAKENING, WITH ONE BAND JUST NORTH OF HOULTON AND
ANOTHER ONE AFFECTING NRN WASHINGTON COUNTY, IN THE VICINTY OF
THE VANCEBORO TO CALAIS AREA. THE LATEST HRRR SHOWS THIS ACTIVITY
RAPIDLY DIMINISHING OVER THE NECT COUPLE HOURS WITH THE PASSAGE OF
THE UPPER TROF.

HAVE UPDATED THE POPS/SKY GRIDS FOR THE OVERNIGHT HOURS TO REFLECT
LATEST TRENDS. OTHERWISE, REMAINDER OF THE OVERNIGHT FORECAST
STILL LOOKS GOOD.

ORGNL DISC: MARKEDLY COLDER AIR WILL CONTINUE TO ADVECT INTO THE
REGION TONIGHT WITH THE COLD UPPER TROUGH PASSAGE NEAR MIDNIGHT.
UNTIL THIS TROUGH CROSSES...LOW LEVEL INSTABILITY WILL PROMOTE
LINES OF SNOW SHOWERS MOVING PARALLEL TO THE UPPER FLOW. CAPE
ACTUALLY INCREASES TONIGHT WITH THE TROUGH. THESE SNOW SHOWERS
WILL BE MOSTLY NORTH OF HOULTON THROUGH THE EVENING BUT GUIDANCE
SUGGEST A BAND COULD CROSS DOWN EAST LATE IN THE EVENING. LITTLE
OR NO ACCUMULATION IS EXPECTED. THE PRIMARY CONCERNS WILL BE
REDUCED VISIBILITY AND STRONG WIND GUSTS UP TO 40 MPH TONIGHT.
THIS WILL CREATE HAZARDOUS CONDITIONS FOR MOTORISTS. THE CURRENT
SPECIAL WEATHER STATEMENT FOR THE SNOW SHOWERS MAY NEED TO BE
EXTENDED THROUGH THE EVENING. SOME SNOW SHOWERS COULD BE MORE
PROLONGED THIS EVENING AS THE UPPER TROUGH CROSSES FOR NORTHERN
AROOSTOOK. ONCE THE UPPER TROUGH PASSES...SKIES WILL CLEAR BUT
WINDS WILL REMAIN VERY STRONG THROUGH SUNDAY MORNING. SUNDAY WILL
FEATURE THE COLDEST HIGH TEMPERATURES OF THE MONTH TO DATE WITH
READINGS IN THE LOW 20S NORTH AND UPPER 20S TO NEAR 30F FOR BANGOR
AND DOWN EAST. WIND CHILLS SUNDAY MORNING WILL BE NEAR ZERO...A
SIGNIFICANT CONTRAST TO RECENT DAYS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
HIGH PRESSURE MOVING OFF THE EAST COAST SUNDAY NIGHT COMBINED WITH
WEAK LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL BRING WARM
ADVECTION TOWARD THE AREA ON MONDAY. SOME SPOTTY LIGHT SNOW WILL BE
POSSIBLE ACROSS THE FAR NORTH SUNDAY NIGHT. SOME LIGHT PRECIPITATION
IN THE FORM OF SNOW OVER THE NORTH AND LIGHT RAIN DOWNEAST WITH SOME
SLEET AND FREEZING RAIN POSSIBLE IN CENTRAL AREAS WILL SPREAD ACROSS
THE REGION MONDAY AS THE LOW MOVES IN. THE LOW WILL LIFT TO OUR
NORTHWEST MONDAY NIGHT AND WEAKEN. SPOTTY LIGHT MIXED PRECIPITATION
WILL BE POSSIBLE IN THE NORTH WITH RAIN SHOWERS OR DRIZZLE IN
CENTRAL AND SOUTHERN AREAS. A WEAK WARM FRONTAL BOUNDARY WILL REMAIN
OVER THE AREA TUESDAY BRINGING A CONTINUATION OF CLOUDY CONDITIONS
WITH SOME SPOTTY RAIN SHOWERS POSSIBLE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE OVER THE MARITIMES WILL BRIEFLY NUDGE OVER THE REGION
TUESDAY NIGHT INTO WEDNESDAY BUT THE AIR WILL REMAIN MILD WITH
LONGWAVE RIDGING ANCHORED OVER THE EAST. A LARGE STORM SYSTEM
TRACKING ACROSS THE NORTH CENTRAL PART OF THE COUNTRY WILL
APPROACH WEDNESDAY NIGHT INTO THURSDAY PULLING WARMER AIR INTO THE
REGION AS THE SYSTEM LIFTS INTO SOUTHERN CANADA. SOME SHOWERS, FOG
AND DRIZZLE WILL BE LIKELY WEDNESDAY NIGHT INTO THURSDAY WITH
UNSEASONABLY WARM AIR ACROSS THE REGION. A COLD FRONT WILL COME
THROUGH THURSDAY NIGHT. GUSTY WEST WINDS AND MODERATELY COOLER
CONDITIONS WILL PREVAIL FOR CHRISTMAS DAY AS THE LOW TRACKS INTO
THE NORTHERN PART OF EASTERN CANADA.

&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: SNOW SHOWERS WILL GENERATE THE RISK OF TEMPO LIFR
CONDITIONS AND A LOT OF LOW LEVEL TURBULENCE THIS
EVENING...MOSTLY FROM PQI NORTHWARD. OTHERWISE...VFR CONDITIONS
ARE EXPECTED WITH VERY GUSTY NW WINDS UP TO 40 MPH. THE WINDS WILL
FURTHER INCREASE TONIGHT AND CONTINUE INTO SUNDAY MORNING. THE
WINDS WILL DECREASE SUNDAY AFTERNOON.

SHORT TERM: CONDITIONS WILL LIKELY DROP TO MVFR IN STRATUS CLOUDS
SUNDAY NIGHT THEN BE MVFR TO IFR MONDAY INTO MONDAY NIGHT IN LOW
CLOUDS. MVFR CONDITIONS ARE LIKELY TUESDAY INTO TUESDAY NIGHT.
CONDITIONS MAY IMPROVE TO VFR DOWNEAST LATE TUESDAY NIGHT. VFR
CONDITIONS ARE LIKELY WEDNESDAY. A RETURN TO IFR IN LOW CLOUDS IS
THEN EXPECTED WEDNESDAY NIGHT INTO THURSDAY IN LOW CLOUDS.

&&

.MARINE...
NEAR TERM: THE GALE IS STILL EXPECTED WITH WIND GUSTS INCREASING
TOWARDS 40 KTS LATER TONIGHT INTO SUNDAY MORNING. SEAS ARE
EXPECTED TO REACH AS HIGH AS 10 FEET.

SHORT TERM: A GALE MAY BE NEEDED ON MONDAY FOR GUSTY WEST WINDS.
AN SCA OR GALE WILL LIKELY BE NEEDED AGAIN CHRISTMAS EVE INTO
CHRISTMAS DAY FOR STRONG GUSTY SOUTH WINDS BECOMING WESTERLY.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ANZ050>052.

&&

$$

NEAR TERM...DUDA/VJN
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...DUDA/VJN/BLOOMER
MARINE...DUDA/VJN/BLOOMER




AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 608 PM CST MON DEC 21 2015

.SHORT TERM: (Through Tuesday Afternoon)
Issued at 120 PM CST Mon Dec 21 2015

The cold front is making steady progress east across the area
with falling temperatures and a wind shift to the west-northwest.
Dry slot and breaks in the overcast allowed St. Louis to top out
at 67 degrees late this morning which tied the record for the
date that was set back in 1967. What a way to start astronomical
winter, which officially begins at 10:48 PM this evening!

Post frontal IFR stratus deck will blanket the CWA this evening and
despite the subsidence behind the storm system, the low level
moisture will be trapped under the inversion and keep the cloud deck
around tonight or allow for dense fog to develop if there is
clearing. HRRR has been very reliable in these post frontal cloud
forecasts as of late and it shows a LIFR cloud deck through at least
14Z on Tuesday.

Believe clouds or fog will try to scatter/dissipate from
southwest to northeast on Tuesday as flow becomes southerly. Have
forecast temperatures a bit cooler for Tuesday across the
northeastern half of the CWA due to this expected cloud cover.

CVKING

.LONG TERM:  (Tuesday Night through Next Monday)
Issued at 120 PM CST Mon Dec 21 2015

Active weather pattern sets up Tuesday night through the
remainder of the forecast. Next shortwave and attendant surface
low/cold front is expected to approach the area from the west
Tuesday night and move across the CWA by late Wednesday evening.
Moisture advection is forecast to increase Tuesday night as the
low level jet increases and showers should be on the increase
after midnight. Can`t rule out a few rumbles of thunder as well,
given MUCAPES around 500 J/KG. This first round of "warm
advection precipitation" should move northeast by late morning on
Wednesday and depending on the amount of clearing and
destablization that can take place across the eastern half of the
CWA, severe thunderstorms may develop ahead and along the cold
front. As with almost any cold season event, the shear and
helicity values are extremely favorable for organized convection.
The question will be the surface based instabilty. The NAM is the
most bullish with around 500-750 J/KG. SPC has placed the eastern
portion of the CWA in a Marginal Risk for Day 3, and historical
analogs (St. Louis University CIPS) certainly support this. Have
introduced severe wording in the HWO and Situational Report to
account for this potential.

Needless to say temperatures will be well above average Tuesday
night and Wednesday. Some of the guidance actually has 70s on
Wednesday afternoon. I would think that is a tad too high, but we
got up to 67 degrees today so I suppose anything is possible this
winter!

The storms, if they develop, should exit rapidly to the east
Wednesday night leaving Christmas Eve and much of Christmas Day dry
and cooler (but yes, still above normal).

Attention then turns to a prolonged rain event Christmas night
through the Holiday Weekend with the prospect of flooding. The
synoptic setup is that the front that drifted to our south moves
back north and sits just to the south of us for a few days with a
classic setup for elevated convection as a deep trof and surface low
develop to our southwest. The front lifts north by early next week
with the system moving over the top of us. GFS has a maximum of
7-10 inches of rain from southwest Missouri through the St. Louis
Metro, the ECWMF has 4-6 inches, and the Central Region SuperBlend
of model data (which includes WPC) has widespread amounts of 5-7
inches. This amount of rain, even spread out over several days,
will cause local streams, creeks and rivers to flood. If
convection occurs and locally higher amounts are realized, then
flash flooding could be a possibility toward the end of the event
once the ground has been thoroughly saturated. Given these
concerns have decided to add mention of flooding in both the HWO
and Situation Report.

Temperatures will remain above normal and fluctuate depending on the
exact placement of the front during the extended portion of the
forecast.

CVKING

&&

.AVIATION:  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 536 PM CST Mon Dec 21 2015

IFR flight conditions over central and northeast Missouri and west
central Illinois will overspread the area through the evening into
the early overnight hours. Timing is uncertain however as the
stratus was moving very slowly earlier this afternoon, but the
last 2 or 3 satellite pictures show the eastern edge of the clouds
surging toward the STL metro area. Will have to update the metro
TAFs if this trend continues. Once IFR cigs overspread the area,
expect low clouds to persist into Tuesday morning. There is some
hint in the guidance that the ceilings will break up over central
Missouri during the pre-dawn hours, but if that occurs expect fog
to form with vsbys at or below 2 miles. IFR conditions until at
least mid morning either way. Should see some improvement to MVFR
or VFR late Tuesday morning or early afternoon, but confidence on
timing is low.

Specifics for KSTL:

Ceilings west of the terminal are expected to move east and affect
Lambert later this evening. Timing is uncertain though as the last
couple of satellite pictures showed the stratus increasing its
eastward speed. If this trend continues, the stratus will reach
the terminal much sooner than 05Z. Will monitor this closely over
the next hour or so and amend as necessary. Once the stratus moves
over the terminal, expect IFR conditions to persist at least
through mid morning. Should see some improvement Tuesday afternoon.

Carney

&&

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

$$

WFO LSX




AREA FORECAST DISCUSSION...UPDATED

NWS BILLINGS MT

 1201 PM MST SUN DEC 20 2015

.UPDATE...

FOG HAS BURN OFF ACROSS MOST OF THE AREA. THERE MAY BE A FEW
PATCHES OF FOG BUT NOTHING WIDESPREAD. WITH VISIBILITIES
RECOVERING HAVE CANCELLED THE DENSE FOG ADVISORY. REIMER

&&

.SHORT TERM...VALID FOR TDY AND MON...

A VERY PROGRESSIVE PATTERN WILL BE OVER SOUTHERN MONTANA AND
NORTHERN WYOMING THROUGH THE EARLY PART OF THE WEEK. THE FAST
MOVING NATURE OF THE ENERGY AND LACK OF AN AMPLIFIED PATTERN WILL
PREVENT A STRONG SURGE OF ARCTIC AIR AND THE DEVELOPMENT OF A
LARGE SNOW PRODUCING SYSTEM. A COUPLE OF DIFFERENT SYSTEMS WILL
WORK THROUGH AND PRODUCE AREAS OF SNOW SHOWERS...BUT THE SYSTEMS
WILL BE FAST MOVING AND THIS IN TURN WILL KEEP SNOW ACCUMULATIONS
DOWN. THE MOST LIKELY LOCATION TO SEE ACCUMULATING SNOW WILL BE
THE SOUTHWEST MOUNTAINS WITH A STEADY STREAM OF MOISTURE FEEDING
INTO THE WESTERN SLOPES.

ONE SYSTEM MOVED ACROSS CENTRAL ZONES OVERNIGHT AND WILL SLIDE
ACROSS SOUTHERN MONTANA THIS MORNING. THIS ENERGY IS PROGGED TO
WEAKEN AS IT PROGRESSES EASTWARD...SO SNOW SHOWER ACTIVITY
ASSOCIATED WITH IT WILL BE LESS DYNAMIC THAN IT WAS OVER WESTERN
AND CENTRAL ZONES OVERNIGHT. WILL LINGER LOW POPS OVER THE
SOUTHERN HALF OF THE AREA THIS MORNING. AREAS OF FOG FORMED BEHIND
THE BAND OF LIGHT TO MODERATE SNOW THAT WORKED THROUGH OVERNIGHT.
HI RESOLUTION MODELS INDICATE THAT SOME LOW CEILINGS AND FOG WILL
PERSIST OVER PARTS OF THE MORNING. RAP SOUNDINGS KEEP LOW CLOUDS
AND SOME FOG IN BILLINGS THROUGH 16Z...THEN LIFT IT OUT AS
STRONGER MIXING WINDS FORM IN THE LOWER LEVELS WITH A LEE TROUGH
FORMING. ADDED AREAS OF FOG FOR PARTS OF THE AREA FOR THE MORNING.

THE NEXT SHORTWAVE TO ADVANCE THROUGH THE AREA WILL BE SUNDAY
NIGHT AND EARLY MONDAY. THIS SYSTEM DOES PACK SOME INSTABILITY
WITH LAPSE RATES OF AROUND 8C/KM FROM 850-500MB. THE MAIN CORE OF
THE WAVE RIDES ACROSS NORTHERN MONTANA...WHICH IS NOT IN A GOOD
LOCATION FOR PRECIPITATION CHANCES. HAVE BRUSHED SOME LOW POPS IN
DUE TO INSTABILITY AND OVERALL STRENGTH OF THE SHORTWAVE TROUGH.
MAY NEED TO RAISE POPS IN FUTURE UPDATES IF THE CORE TRACKS A
LITTLE FARTHER SOUTH. YET ANOTHER WAVE WORKS IN MONDAY NIGHT INTO
TUESDAY MORNING FOR A CHANCE OF SNOW SHOWERS. THIS SYSTEM WAS
TRACKING A LITTLE FARTHER SOUTH THUS MAY HAVE A BETTER CHANCE OF
PRODUCING SNOW SHOWERS FOR THE FORECAST AREA. TEMPERATURES THE
NEXT COUPLE OF DAY SHOULD BE RIGHT AROUND SEASONAL AVERAGES. TWH

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

EXTENDED MODELS WERE IN OVERALL AGREEMENT THROUGH THE PERIOD IN
SHOWING A PROGRESSIVE WESTERLY FLOW WITH MULTIPLE WAVES MOVING
THROUGH THE FLOW. MODELS CONTINUE TO BRING A SPLITTING TROUGH INTO
THE REGION THU NIGHT THROUGH FRI NIGHT. THE MODELS HANDLE THIS
FEATURE DIFFERENTLY INTO SAT. THE GFS AND ECMWF SHOW MOISTURE OVER
THE AREA IN W FLOW THU NIGHT THEN DRY OUT THE MOISTURE ON FRI/FRI
NIGHT. ECMWF HINTS AT TRYING TO BRING WRAP-AROUND MOISTURE FROM A
700 MB LOW INTO THE SE BY SAT MORNING. THESE PERIODS APPEAR TO BE
IN FLUX BASED ON HOW THE MODELS LOOKED LAST NIGHT...SO TO FOLLOW
TRENDS...JUST HAVE LOW POPS OVER PORTIONS OF THE AREA THROUGH FRI
NIGHT.

ANOTHER DIFFERENCE WITH THESE NEW MODEL RUNS IS HOW THE PRESSURE
GRADIENT SETS UP QUITE STRONGLY OVER THE AREA ON SAT AND CONTINUES
INTO SUN WITH SOME DIFFERENCES BETWEEN THE MODELS ON HOW THE
GRADIENT SETS UP. BASED ON THE GRADIENT STRENGTH...HAVE INCREASED
GAP FLOW WINDS INTO THE ADVISORY/WARNING CRITERIA WIND SPEEDS
DURING THIS TIME FRAME. WILL DEFINITELY NEED TO WATCH MODEL TRENDS
TO SEE IF THIS PATTERN PERSISTS FROM RUN-TO-RUN.

OTHERWISE...MODELS BRING A SHORTWAVE THROUGH THE AREA ON TUE WITH
MORE ENERGY ON WED. WEAKER ENERGY FOLLOWS ON THU. NEAR-NORMAL
TEMPERATURES WILL CONTINUE WITH CHANCES FOR SNOW EACH
PERIOD...ESPECIALLY IN THE MOUNTAINS. FRI WILL BE THE COLDEST DAY
WITH 850 MB TEMPERATURES AROUND -8 DEGREES C...THEN TEMPERATURES
WILL MODERATE THROUGH THE WEEKEND. ARTHUR
&&

.AVIATION...

VLIFR CONDITIONS ARE EXPECTED TO PERSIST AT KBIL UNTIL AROUND NOON...
DEPENDING ON WHEN HIGH CLOUDS CLEAR OUT. AFTERWARD... CONDITIONS
WILL IMPROVE TO MVFR OR BETTER. THE FOG MAY RETURN TONIGHT BUT
CONFIDENCE IN THIS OCCURRING IS NOT VERY HIGH AT THIS TIME. IFR TO
VLIFR CONDITIONS DUE TO FOG OVER KMLS WILL CONTINUE THIS MORNING
AND POSSIBLY THROUGH THE PERIOD. MVFR CONDITIONS HAVE ENDED IN
KSHR... WITH VFR EXPECTED TO CONTINUE INTO TONIGHT. OTHERWISE VFR
SHOULD PREVAIL ACROSS OUR AREA THROUGH TONIGHT. THE
BEARTOOTHS/ABSAROKAS AND NE BIG HORNS WILL BE MOSTLY OBSCURED
TODAY AND WILL CONTINUE TONIGHT FOR THE BEARTOOTHS/ABSAROKAS.
MROWELL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 033 021/034 021/035 020/031 015/027 007/022 009/028
    1/B 21/N    22/J    23/J    21/E    11/B    11/N
LVM 035 021/032 022/034 019/028 016/027 006/021 009/026
    2/S 32/S    43/J    43/J    22/J    22/J    11/N
HDN 034 018/036 017/036 014/034 009/028 002/020 000/027
    1/B 21/B    22/W    23/J    21/E    11/B    11/U
MLS 032 020/035 016/033 014/029 010/026 005/023 005/026
    1/B 12/S    12/J    23/J    21/E    11/E    11/U
4BQ 033 019/036 017/035 015/029 008/027 005/023 008/027
    2/S 12/S    11/E    23/J    21/E    11/E    11/U
BHK 031 019/034 017/033 015/027 013/027 008/023 009/029
    1/B 02/S    01/E    32/J    21/E    11/E    11/B
SHR 033 017/035 017/036 014/029 008/027 004/023 004/029
    3/S 12/S    22/J    23/J    21/B    12/J    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



AREA FORECAST DISCUSSION...UPDATED

NWS BILLINGS MT

 925 AM MST SUN DEC 20 2015

.UPDATE...

FOG CONTINUES TO LINGER ACROSS SOUTHEASTERN MONTANA AND INTO
BILLINGS...WITH VISIBILITIES REMAINING AROUND A QUARTER MILE AT
MANY LOCATIONS. THE TRENDS IN THE HRRR VISIBILITIES AND LOW LEVEL
HUMIDITY VALUES CONTINUE THE LOWER VISIBILITIES INTO THE
AFTERNOON. HAVE GONE WITH A DENSE FOG ADVISORY THROUGH 3 PM.
THINGS SHOULD BEGIN IMPROVING AROUND BILLINGS BY NOON...AND SLOWLY
IMPROVE EASTWARD THROUGH THE AFTERNOON. GIVEN THE THE SUN ANGLE IS
AT ITS LOWEST AND WINDS WILL REMAIN LIGHT...IT WILL BE A STRUGGLE
TO BURN OFF ALL OF THE FOG ESPECIALLY FROM MILES CITY EASTWARD.
REIMER

&&

.SHORT TERM...VALID FOR TDY AND MON...

A VERY PROGRESSIVE PATTERN WILL BE OVER SOUTHERN MONTANA AND
NORTHERN WYOMING THROUGH THE EARLY PART OF THE WEEK. THE FAST
MOVING NATURE OF THE ENERGY AND LACK OF AN AMPLIFIED PATTERN WILL
PREVENT A STRONG SURGE OF ARCTIC AIR AND THE DEVELOPMENT OF A
LARGE SNOW PRODUCING SYSTEM. A COUPLE OF DIFFERENT SYSTEMS WILL
WORK THROUGH AND PRODUCE AREAS OF SNOW SHOWERS...BUT THE SYSTEMS
WILL BE FAST MOVING AND THIS IN TURN WILL KEEP SNOW ACCUMULATIONS
DOWN. THE MOST LIKELY LOCATION TO SEE ACCUMULATING SNOW WILL BE
THE SOUTHWEST MOUNTAINS WITH A STEADY STREAM OF MOISTURE FEEDING
INTO THE WESTERN SLOPES.

ONE SYSTEM MOVED ACROSS CENTRAL ZONES OVERNIGHT AND WILL SLIDE
ACROSS SOUTHERN MONTANA THIS MORNING. THIS ENERGY IS PROGGED TO
WEAKEN AS IT PROGRESSES EASTWARD...SO SNOW SHOWER ACTIVITY
ASSOCIATED WITH IT WILL BE LESS DYNAMIC THAN IT WAS OVER WESTERN
AND CENTRAL ZONES OVERNIGHT. WILL LINGER LOW POPS OVER THE
SOUTHERN HALF OF THE AREA THIS MORNING. AREAS OF FOG FORMED BEHIND
THE BAND OF LIGHT TO MODERATE SNOW THAT WORKED THROUGH OVERNIGHT.
HI RESOLUTION MODELS INDICATE THAT SOME LOW CEILINGS AND FOG WILL
PERSIST OVER PARTS OF THE MORNING. RAP SOUNDINGS KEEP LOW CLOUDS
AND SOME FOG IN BILLINGS THROUGH 16Z...THEN LIFT IT OUT AS
STRONGER MIXING WINDS FORM IN THE LOWER LEVELS WITH A LEE TROUGH
FORMING. ADDED AREAS OF FOG FOR PARTS OF THE AREA FOR THE MORNING.

THE NEXT SHORTWAVE TO ADVANCE THROUGH THE AREA WILL BE SUNDAY
NIGHT AND EARLY MONDAY. THIS SYSTEM DOES PACK SOME INSTABILITY
WITH LAPSE RATES OF AROUND 8C/KM FROM 850-500MB. THE MAIN CORE OF
THE WAVE RIDES ACROSS NORTHERN MONTANA...WHICH IS NOT IN A GOOD
LOCATION FOR PRECIPITATION CHANCES. HAVE BRUSHED SOME LOW POPS IN
DUE TO INSTABILITY AND OVERALL STRENGTH OF THE SHORTWAVE TROUGH.
MAY NEED TO RAISE POPS IN FUTURE UPDATES IF THE CORE TRACKS A
LITTLE FARTHER SOUTH. YET ANOTHER WAVE WORKS IN MONDAY NIGHT INTO
TUESDAY MORNING FOR A CHANCE OF SNOW SHOWERS. THIS SYSTEM WAS
TRACKING A LITTLE FARTHER SOUTH THUS MAY HAVE A BETTER CHANCE OF
PRODUCING SNOW SHOWERS FOR THE FORECAST AREA. TEMPERATURES THE
NEXT COUPLE OF DAY SHOULD BE RIGHT AROUND SEASONAL AVERAGES. TWH

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

EXTENDED MODELS WERE IN OVERALL AGREEMENT THROUGH THE PERIOD IN
SHOWING A PROGRESSIVE WESTERLY FLOW WITH MULTIPLE WAVES MOVING
THROUGH THE FLOW. MODELS CONTINUE TO BRING A SPLITTING TROUGH INTO
THE REGION THU NIGHT THROUGH FRI NIGHT. THE MODELS HANDLE THIS
FEATURE DIFFERENTLY INTO SAT. THE GFS AND ECMWF SHOW MOISTURE OVER
THE AREA IN W FLOW THU NIGHT THEN DRY OUT THE MOISTURE ON FRI/FRI
NIGHT. ECMWF HINTS AT TRYING TO BRING WRAP-AROUND MOISTURE FROM A
700 MB LOW INTO THE SE BY SAT MORNING. THESE PERIODS APPEAR TO BE
IN FLUX BASED ON HOW THE MODELS LOOKED LAST NIGHT...SO TO FOLLOW
TRENDS...JUST HAVE LOW POPS OVER PORTIONS OF THE AREA THROUGH FRI
NIGHT.

ANOTHER DIFFERENCE WITH THESE NEW MODEL RUNS IS HOW THE PRESSURE
GRADIENT SETS UP QUITE STRONGLY OVER THE AREA ON SAT AND CONTINUES
INTO SUN WITH SOME DIFFERENCES BETWEEN THE MODELS ON HOW THE
GRADIENT SETS UP. BASED ON THE GRADIENT STRENGTH...HAVE INCREASED
GAP FLOW WINDS INTO THE ADVISORY/WARNING CRITERIA WIND SPEEDS
DURING THIS TIME FRAME. WILL DEFINITELY NEED TO WATCH MODEL TRENDS
TO SEE IF THIS PATTERN PERSISTS FROM RUN-TO-RUN.

OTHERWISE...MODELS BRING A SHORTWAVE THROUGH THE AREA ON TUE WITH
MORE ENERGY ON WED. WEAKER ENERGY FOLLOWS ON THU. NEAR-NORMAL
TEMPERATURES WILL CONTINUE WITH CHANCES FOR SNOW EACH
PERIOD...ESPECIALLY IN THE MOUNTAINS. FRI WILL BE THE COLDEST DAY
WITH 850 MB TEMPERATURES AROUND -8 DEGREES C...THEN TEMPERATURES
WILL MODERATE THROUGH THE WEEKEND. ARTHUR

&&

.AVIATION...

VLIFR CONDITIONS ARE EXPECTED TO PERSIST AT KBIL UNTIL AROUND NOON...
DEPENDING ON WHEN HIGH CLOUDS CLEAR OUT. AFTERWARD... CONDITIONS
WILL IMPROVE TO MVFR OR BETTER. THE FOG MAY RETURN TONIGHT BUT
CONFIDENCE IN THIS OCCURRING IS NOT VERY HIGH AT THIS TIME. IFR TO
VLIFR CONDITIONS DUE TO FOG OVER KMLS WILL CONTINUE THIS MORNING
AND POSSIBLY THROUGH THE PERIOD. MVFR CONDITIONS HAVE ENDED IN
KSHR... WITH VFR EXPECTED TO CONTINUE INTO TONIGHT. OTHERWISE VFR
SHOULD PREVAIL ACROSS OUR AREA THROUGH TONIGHT. THE
BEARTOOTHS/ABSAROKAS AND NE BIG HORNS WILL BE MOSTLY OBSCURED
TODAY AND WILL CONTINUE TONIGHT FOR THE BEARTOOTHS/ABSAROKAS.
MROWELL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 033 021/034 021/035 020/031 015/027 007/022 009/028
    2/S 21/N    22/J    23/J    21/E    11/B    11/N
LVM 035 021/032 022/034 019/028 016/027 006/021 009/026
    2/S 32/S    43/J    43/J    22/J    22/J    11/N
HDN 034 018/036 017/036 014/034 009/028 002/020 000/027
    2/S 21/B    22/W    23/J    21/E    11/B    11/U
MLS 032 020/035 016/033 014/029 010/026 005/023 005/026
    1/B 12/S    12/J    23/J    21/E    11/E    11/U
4BQ 033 019/036 017/035 015/029 008/027 005/023 008/027
    2/S 12/S    11/E    23/J    21/E    11/E    11/U
BHK 031 019/034 017/033 015/027 013/027 008/023 009/029
    1/E 02/S    01/E    32/J    21/E    11/E    11/B
SHR 033 017/035 017/036 014/029 008/027 004/023 004/029
    3/S 12/S    22/J    23/J    21/B    12/J    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 3 PM MST THIS AFTERNOON
      FOR ZONES 30>33-35-37.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



AREA FORECAST DISCUSSION

NWS BILLINGS MT

 311 AM MST SUN DEC 20 2015

.SHORT TERM...VALID FOR TDY AND MON...

A VERY PROGRESSIVE PATTERN WILL BE OVER SOUTHERN MONTANA AND
NORTHERN WYOMING THROUGH THE EARLY PART OF THE WEEK. THE FAST
MOVING NATURE OF THE ENERGY AND LACK OF AN AMPLIFIED PATTERN WILL
PREVENT A STRONG SURGE OF ARCTIC AIR AND THE DEVELOPMENT OF A
LARGE SNOW PRODUCING SYSTEM. A COUPLE OF DIFFERENT SYSTEMS WILL
WORK THROUGH AND PRODUCE AREAS OF SNOW SHOWERS...BUT THE SYSTEMS
WILL BE FAST MOVING AND THIS IN TURN WILL KEEP SNOW ACCUMULATIONS
DOWN. THE MOST LIKELY LOCATION TO SEE ACCUMULATING SNOW WILL BE
THE SOUTHWEST MOUNTAINS WITH A STEADY STREAM OF MOISTURE FEEDING
INTO THE WESTERN SLOPES.

ONE SYSTEM MOVED ACROSS CENTRAL ZONES OVERNIGHT AND WILL SLIDE
ACROSS SOUTHERN MONTANA THIS MORNING. THIS ENERGY IS PROGGED TO
WEAKEN AS IT PROGRESSES EASTWARD...SO SNOW SHOWER ACTIVITY
ASSOCIATED WITH IT WILL BE LESS DYNAMIC THAN IT WAS OVER WESTERN
AND CENTRAL ZONES OVERNIGHT. WILL LINGER LOW POPS OVER THE
SOUTHERN HALF OF THE AREA THIS MORNING. AREAS OF FOG FORMED BEHIND
THE BAND OF LIGHT TO MODERATE SNOW THAT WORKED THROUGH OVERNIGHT.
HI RESOLUTION MODELS INDICATE THAT SOME LOW CEILINGS AND FOG WILL
PERSIST OVER PARTS OF THE MORNING. RAP SOUNDINGS KEEP LOW CLOUDS
AND SOME FOG IN BILLINGS THROUGH 16Z...THEN LIFT IT OUT AS
STRONGER MIXING WINDS FORM IN THE LOWER LEVELS WITH A LEE TROUGH
FORMING. ADDED AREAS OF FOG FOR PARTS OF THE AREA FOR THE MORNING.

THE NEXT SHORTWAVE TO ADVANCE THROUGH THE AREA WILL BE SUNDAY
NIGHT AND EARLY MONDAY. THIS SYSTEM DOES PACK SOME INSTABILITY
WITH LAPSE RATES OF AROUND 8C/KM FROM 850-500MB. THE MAIN CORE OF
THE WAVE RIDES ACROSS NORTHERN MONTANA...WHICH IS NOT IN A GOOD
LOCATION FOR PRECIPITATION CHANCES. HAVE BRUSHED SOME LOW POPS IN
DUE TO INSTABILITY AND OVERALL STRENGTH OF THE SHORTWAVE TROUGH.
MAY NEED TO RAISE POPS IN FUTURE UPDATES IF THE CORE TRACKS A
LITTLE FARTHER SOUTH. YET ANOTHER WAVE WORKS IN MONDAY NIGHT INTO
TUESDAY MORNING FOR A CHANCE OF SNOW SHOWERS. THIS SYSTEM WAS
TRACKING A LITTLE FARTHER SOUTH THUS MAY HAVE A BETTER CHANCE OF
PRODUCING SNOW SHOWERS FOR THE FORECAST AREA. TEMPERATURES THE
NEXT COUPLE OF DAY SHOULD BE RIGHT AROUND SEASONAL AVERAGES. TWH

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

EXTENDED MODELS WERE IN OVERALL AGREEMENT THROUGH THE PERIOD IN
SHOWING A PROGRESSIVE WESTERLY FLOW WITH MULTIPLE WAVES MOVING
THROUGH THE FLOW. MODELS CONTINUE TO BRING A SPLITTING TROUGH INTO
THE REGION THU NIGHT THROUGH FRI NIGHT. THE MODELS HANDLE THIS
FEATURE DIFFERENTLY INTO SAT. THE GFS AND ECMWF SHOW MOISTURE OVER
THE AREA IN W FLOW THU NIGHT THEN DRY OUT THE MOISTURE ON FRI/FRI
NIGHT. ECMWF HINTS AT TRYING TO BRING WRAP-AROUND MOISTURE FROM A
700 MB LOW INTO THE SE BY SAT MORNING. THESE PERIODS APPEAR TO BE
IN FLUX BASED ON HOW THE MODELS LOOKED LAST NIGHT...SO TO FOLLOW
TRENDS...JUST HAVE LOW POPS OVER PORTIONS OF THE AREA THROUGH FRI
NIGHT.

ANOTHER DIFFERENCE WITH THESE NEW MODEL RUNS IS HOW THE PRESSURE
GRADIENT SETS UP QUITE STRONGLY OVER THE AREA ON SAT AND CONTINUES
INTO SUN WITH SOME DIFFERENCES BETWEEN THE MODELS ON HOW THE
GRADIENT SETS UP. BASED ON THE GRADIENT STRENGTH...HAVE INCREASED
GAP FLOW WINDS INTO THE ADVISORY/WARNING CRITERIA WIND SPEEDS
DURING THIS TIME FRAME. WILL DEFINITELY NEED TO WATCH MODEL TRENDS
TO SEE IF THIS PATTERN PERSISTS FROM RUN-TO-RUN.

OTHERWISE...MODELS BRING A SHORTWAVE THROUGH THE AREA ON TUE WITH
MORE ENERGY ON WED. WEAKER ENERGY FOLLOWS ON THU. NEAR-NORMAL
TEMPERATURES WILL CONTINUE WITH CHANCES FOR SNOW EACH
PERIOD...ESPECIALLY IN THE MOUNTAINS. FRI WILL BE THE COLDEST DAY
WITH 850 MB TEMPERATURES AROUND -8 DEGREES C...THEN TEMPERATURES
WILL MODERATE THROUGH THE WEEKEND. ARTHUR

&&

.AVIATION...

VLIFR CONDITIONS ARE EXPECTED TO PERSIST AT KBIL UNTIL AROUND
17Z. AFTERWARD...CONDITIONS WILL IMPROVE TO MVFR. THE FOG MAY
RETURN TONIGHT BUT CONFIDENCE IN THIS OCCURRING IS NOT VERY HIGH
AT THIS TIME. MVFR/IFR CONDITIONS IN SNOW AND FOG OVER KMLS WILL
CONTINUE THIS MORNING...THEN LOW CEILINGS WILL REMAIN INTO
TONIGHT. MVFR TO LIFR CONDITIONS IN KSHR WILL IMPROVE BY
18Z...WITH VFR EXPECTED THIS AFTERNOON AND TONIGHT. MVFR
CONDITIONS ARE POSSIBLE IN KLVM EARLY THIS MORNING...OTHERWISE VFR
WILL PREVAIL THROUGH TONIGHT. THE BEARTOOTHS/ABSAROKAS AND NE BIG
HORNS WILL BE MOSTLY OBSCURED TODAY. OBSCURATIONS WILL CONTINUE
TONIGHT FOR THE BEARTOOTHS/ABSAROKAS. THERE WILL BE AREAS OF
OBSCURATION OVER THE CRAZYS AND NE BIG HORNS. ARTHUR

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 033 021/034 021/035 020/031 015/027 007/022 009/028
    2/S 21/N    22/J    23/J    21/E    11/B    11/N
LVM 035 021/032 022/034 019/028 016/027 006/021 009/026
    2/S 32/S    43/J    43/J    22/J    22/J    11/N
HDN 034 018/036 017/036 014/034 009/028 002/020 000/027
    2/S 21/B    22/W    23/J    21/E    11/B    11/U
MLS 032 020/035 016/033 014/029 010/026 005/023 005/026
    1/E 12/S    12/J    23/J    21/E    11/E    11/U
4BQ 033 019/036 017/035 015/029 008/027 005/023 008/027
    2/S 12/S    11/E    23/J    21/E    11/E    11/U
BHK 031 019/034 017/033 015/027 013/027 008/023 009/029
    1/E 02/S    01/E    32/J    21/E    11/E    11/B
SHR 033 017/035 017/036 014/029 008/027 004/023 004/029
    3/S 12/S    22/J    23/J    21/B    12/J    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



AREA FORECAST DISCUSSION

NWS ELKO NV

 242 AM PST SUN DEC 20 2015

.SYNOPSIS...A SLEW OF PACIFIC STORMS WILL PUSH INTO THE GREAT
BASIN THIS WEEK. THE FIRST SHOT OF MOISTURE IS EXPECTED LATER
TODAY BUT ONLY FOR NORTHERN NEVADA. THE MAIN EVENT WILL BE THE
MONDAY AND TUESDAY STORM WHICH WILL DUMP MOISTURE ACROSS NORTHERN
AND CENTRAL NEVADA. THIS MONDAY TUESDAY STORM WILL BRING SEVERAL
INCHES OF SNOW TO MOST VALLEY LOCATIONS AND WILL YIELD HEFTY
AMOUNTS OF SNOW IN THE MOUNTAINS. ANOTHER SYSTEM IS EXPECTED ON
THURSDAY...WHICH WILL ALSO BRING SNOW TO THE REGION.


&&

.SHORT TERM...TODAY THROUGH TUESDAY. THE LATEST RADAR IMAGE FROM
KLRX HAS ISOLATED SHOWERS OVER PORTIONS OF ELKO...LANDER AND
EUREKA COUNTIES. THE HRRR HAS THESE POCKETS OF MOISTURE PETERING
OUT THIS MORNING. BUT UPSTREAM...THE HRRR HAS A BOUNTY OF QPF JUST
WEST OF THE LKN...THAT WILL GRADUALLY PUSH INTO HUMBOLDT COUNTY.
THE PRIMARY FORCING MECHANISM WILL BE ISENTROPIC LIFT. THE QPF
WILL BE CONTAINED IN THE NORTHERN LKN ZONES. THE STORM THAT
EVERYONE HAS BEEN WATCHING IS THE MONDAY-TUESDAY EVENT...WHEN THE
ATMOSPHERIC RIVER SUCCESSFULLY PUSHES BEYOND THE COASTAL RANGES
AND SIERRA. THE NAM AND THE GFS...BOTH DEPICT A BOATLOAD OF QPF.
THE MAIN DIFFERENCE IS THE AMOUNT OF COLD AIR PRESENT. THIS
PACKAGE REFLECTS THE WARMER GFS SOLUTION WHICH IMPACTS THE SNOW
RATIOS AND THE SNOW GRIDS. HIGH CONFIDENCE THAT THIS WILL BE A
MAJOR QPF EVENT...NOT AS CONFIDENT ABOUT THE SNOW AMOUNTS IN THE
VALLEY FLOORS. KEPT THE WATCH IN PLACE...BUT DID NOT
UPGRADE IT AT THIS TIME.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. MODELS LARGELY AGREE ON
NORTHWEST FLOW WITH A TIGHT THERMAL GRADIENT ALOFT THROUGH EARLY
THURSDAY. EMBEDDED SHORT WAVES WILL KEEP POPS IN THE
PICTURE...TAPERING QUICKLY OFF FROM TUESDAY`S STORM. WEDNESDAY WILL
BE RELATIVELY "DRY" BUT NOT POPLESS...BY COMPARISON ONLY.

00Z RUNS OF BOTH LONG RANGE MODELS SHOWS THE QUASI-ZONAL FLOW
BUCKLING AS A SHORT WAVE DIGS ALONG THE COAST STARTING WEDNESDAY
NIGHT AND REACHING THE GREAT BASIN BY THURSDAY MID DAY. POPS
INCREASE DRAMATICALLY CHRISTMAS EVE AND RUN THROUGH CHRISTMAS. IT`S
LIKELY THAT MOST OF NORTHERN NEVADA WILL HAVE A WHITE CHRISTMAS.
IT`S POSSIBLE THE EASTERN NEVADA WILL...AND THERE`S HOPE FOR EVEN
NORTHERN NYE COUNTY. AMOUNTS? TOO SOON TO TELL...BUT THE UPPER
DYNAMICS ARE THERE AT LEAST IN THE MODELS. DISPLACEMENT OF A JET
STREAK WILL TELL...HOWEVER. ON THE WEEKEND...A RIDGE BUILDS IN
ADVANCE OF THE ***NEXT*** SHORT WAVE...BUT ITS ORIENTATION AND
PLACEMENT ETC ARE NOT AGREED UPON. HAVE THEREFORE KEPT SOME POPS IN
BUT MUCH LOWER THAN THE CHRISTMAS TIME FRAME.

WITH SNOW COVER...TEMPS WILL REMAIN DOWN DESPITE ANY RIDGING.

&&

.AVIATION...QUICK BREAK SUNDAY MORNING BETWEEN BATCHES OF SNOW
SHOWERS OVER NORTHERN NEVADA.  A LONG STRETCH OF MOISTURE ARRIVES IN
NORTHWEST NEVADA SUNDAY AFTERNOON AND REMAINS IN PLACE THROUGH 12Z
MONDAY. MVFR CIGS/VISBY LIKELY AT KWMC...KEKO...KELY FROM SUNDAY
AFTERNOON THROUGH 12Z MONDAY. VFR AT KTPH. OUTLOOK FOR LATE MONDAY
INTO TUESDAY...BAD. POSSIBLY MOST SERIOUS WINTER STORM OF THE SEASON
SO FAR.

&&

.LKN WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
HUMBOLDT COUNTY-NORTHERN ELKO COUNTY-NORTHERN LANDER COUNTY AND
NORTHERN EUREKA COUNTY-RUBY MOUNTAINS AND EAST HUMBOLDT RANGE-
SOUTH CENTRAL ELKO COUNTY-SOUTHWEST ELKO COUNTY.

&&

$$

97/98/98



AREA FORECAST DISCUSSION

NWS BUFFALO NY

 1204 AM EST SUN DEC 20 2015

.SYNOPSIS...
BANDS OF LAKE EFFECT SNOW WILL CONTINUE SOUTH AND EAST OF LAKE
ONTARIO OVERNIGHT. HIGH PRESSURE WILL THEN BUILD ACROSS THE LOWER
GREAT LAKES SUNDAY...BRINGING A RETURN TO DRY WEATHER AND WARMER
TEMPERATURES SUNDAY. A SERIES OF STORM SYSTEMS CROSSING THE GREAT
LAKES WILL BRING A RETURN TO WET AND UNSEASONABLY MILD TEMPERATURES
FOR MUCH OF THE COMING HOLIDAY WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
LAKE EFFECT SNOW EAST OF LAKE ERIE WEAKENED EARLY THIS EVENING IN
RESPONSE TO A LOWERING SUBSIDENCE INVERSION. 00Z KBUF SOUNDING
SHOWED THIS INVERSION AT 6KT. THE INVERSION LEVEL OVER LAKE ONTARIO
SHOULD BE CLOSER TO 8KFT /PER 00Z NAM BUFKIT/ WHICH WILL CONTINUE TO
SUPPORT A SEVERAL BROKEN DISORGANIZED BANDS OF LAKE EFFECT SNOW
THROUGH MUCH OF THE OVERNIGHT HOURS. LATEST RADAR SHOWS SNOW SHOWERS
WITH A LAKE HURON CONNECTION ON WESTERLY FLOW STRETCHING DOWN THE
LONG AXIS OF THE LAKE. LIGHT SNOW SHOWERS ARE FALLING ALONG THE
SOUTHERN LAKE ONTARIO SHORE COUNTIES WHERE THE FORECAST HAS BEEN
UPDATED WITH 2-3 INCHES OF SNOWFALL. THE MOST INTENSE RETURNS
STRETCHING WEST TO EAST ACROSS OSWEGO AND SOUTHERN LEWIS COUNTIES.
THERE IS A POTENTIAL FOR ANOTHER 2-4 OR SO INCHES OVERNIGHT ACROSS
CENTRAL AND SOUTHERN OSWEGO AND SOUTHERN LEWIS COUNTIES. GIVEN THE
SLOW SOUTHERLY TREND TO THE BAND AS WINDS VEER...A LAKE EFFECT SNOW
ADVISORY CONTINUES FOR NORTHERN CAYUGA COUNTY THROUGH 12Z SUNDAY FOR
2-4 MORE INCHES OF SNOW.

THERE IS HOWEVER SEVERAL VERY NARROW SNOW BANDS WITH A GEORGIAN BAY
CONNECTION PRESSING SOUTH ACROSS JEFFERSON COUNTY. ONLY EXPECT AN
ADDITIONAL INCH OR TWO OF ACCUMULATION WITH THIS OVERNIGHT BEFORE IT
MERGES WITH THE SOUTHERN BAND PER 01Z/20 HRRR RUN AND 12Z/19 RGEM
MODEL.

OUTSIDE OF LAKE EFFECT BANDS...WE MAY SEE A FEW FLURRIES ON THE EDGE
OF THE BANDS. CLOUD COVER AND INCREASING WARM ADVECTION...ESPECIALLY
ACROSS WESTERN NEW YORK...WILL LIMIT TEMPERATURE FALLS OVERNIGHT
WITH LOWS IN THE 20S.

AS WE MOVE INTO SUNDAY...A SURFACE RIDGE WILL TRANSIT THE FORECAST
AREA...BRINGING AN END TO ANY LINGERING SNOWS DURING THE FIRST PART
OF THE MORNING. THE AFTERNOON SHOULD FEATURE DECREASING CLOUD
COVER...THOUGH WITH WARM ADVECTION BEGINNING TO TAKE HOLD ACROSS
THE AREA...WE MAY SEE MID/HIGH CLOUDS INCREASE LATER IN THE DAY.
TEMPERATURES WILL RISE BACK ABOVE FREEZING ACROSS THE BULK OF THE
FORECAST AREA AS AFOREMENTIONED WARM ADVECTION TAKES HOLD AS THE
CENTER OF THE SURFACE HIGH MOVES OFF THE EAST COAST.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
SUNDAY NIGHT SURFACE HIGH PRESSURE WILL BE FOUND JUST TO OUR
EAST...WITH A SOUTHERLY FLOW OF WIND ON THE FEATURES WESTERN FLANK.
IT SHOULD BE A QUIET NIGHT...WITH TEMPERATURES DROPPING EARLY INTO
THE UPPER 20S AND LOWER 30S. THE SOUTHERLY WIND...INCREASING CLOUDS
FROM THE WEST AND WARM AIR ADVECTION SHOULD ALLOW FOR SURFACE
TEMPERATURES TO RISE A FEW DEGREES AFTER MIDNIGHT.

THE NEXT STORM SYSTEM WILL BE AN AREA OF LOW PRESSURE TRACKING FROM
THE PLAINS SUNDAY NIGHT...AND THROUGH THE CENTRAL GREAT LAKES ON
MONDAY. AHEAD OF THIS SYSTEM A LLJ WILL BE STRENGTHENING TO 50 TO 60
KNOTS. CONVERGENCE AHEAD OF THIS JET...COMBINED WITH A SHORTWAVE
RIPPLING SOUTHWEST TO NORTHEAST THROUGH THE LOW GREAT LAKES REGION
WILL DEVELOP AN AREA OF RAIN SHOWERS. THE RISE IN SURFACE
TEMPERATURES LATE SUNDAY NIGHT SHOULD PUSH ALL AREAS ABOVE FREEZING
AT THE ONSET OF THE PRECIPITATION MONDAY...AND WILL HAVE JUST PLAIN
RAIN SHOWERS IN THE GRIDS.

MONDAY WILL ALSO BECOME BREEZY AS THIS LLJ BEGINS TO MIX DOWN TO THE
SURFACE...ESPECIALLY DOWNWIND OF THE GREAT LAKES. GUSTS UP TO 40 MPH
WILL BE POSSIBLE ACROSS THE TRADITIONAL WINDY LOCATIONS NORTHEAST OF
THE LAKES. THE SURFACE LOW TO THE WEST WILL REMAIN NEUTRAL...OR
SLOWLY FILL WHICH WILL LIMIT THE AGEOSTROPHIC COMPONENT OF THE
WIND...AIDING TO LIKELY KEEP GUSTS BELOW ADVISORY CRITERIA.

MONDAY NIGHT AND TUESDAY THIS LOW WILL WEAKEN AS IT DRIFTS BY TO OUR
NORTH ACROSS SOUTHERN CANADA. A WEAK COLD FRONT WILL PASS INTO OUR
REGION LATE MONDAY AND TUESDAY...SERVING AS A BOUNDARY FOR CONTINUED
SCATTERED LIGHT RAIN SHOWERS. CLOUD COVER MONDAY NIGHT WILL HOLD
TEMPERATURES TO THE 40S FOR OVERNIGHT LOWS...WHILE ON TUESDAY
TEMPERATURES WILL REBOUND BACK INTO THE UPPER 40S...WITH A FEW
SPOTTY 50 READINGS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
BASED ON THE 18Z GFS/12Z ECMWF AND THE UNSEASONABLY WARM SOUTHERLY
FLOW FORECAST WE HAVE RAISED HIGH TEMPERATURES FOR WED/THU A FEW
DEGREES. NO OTHER CHANGES ON THE EVENING UPDATE.

TEMPERATURES WILL TRANSITION TO MUCH ABOVE SEASONAL NORMALS AT
THE START OF THIS PERIOD. A FAST NORTHERN PACIFIC FLOW WILL CARRY
CLUSTERS OF ENERGY ACROSS THE ROCKIES...DEEPENING A LONG WAVE
TROUGH OVER THE CENTRAL PLAINS BY TUESDAY NIGHT. DOWNSTREAM...A
RIDGE OF HIGH PRESSURE WILL DEVELOP OVER THE EASTERN US AND
SOUTHERN CANADA. WITHIN THIS RIDGE A SOUTHERLY FLOW WILL BUILD
WARMTH...AS WELL AS CARRY MOISTURE FROM THE SOUTH NORTHWARD.

AT THE SURFACE A WEAK AREA OF HIGH PRESSURE WILL YIELD A MAINLY DRY
TUESDAY NIGHT. SOUTHERLY FLOW WILL AGAIN MAINTAIN TEMPERATURES IN
THE UPPER 30S TO LOWER 40S OVERNIGHT. ON WEDNESDAY EXPECT RAIN
SHOWERS TO AGAIN RETURN TO THE REGION AS BUILDING MOISTURE AHEAD OF
THE UPSTREAM TROUGH BUILDS OVER OUR REGION. PWATS WILL CLIMB TO
AROUND AN INCH ON WEDNESDAY. A SHORTWAVE IN ADVANCE OF THE MAIN
UPSTREAM TROUGH WILL CREST THE UPPER LEVEL RIDGE OVER THE EAST
WEDNESDAY...PROVIDING ENOUGH LIFT TO GENERATE A WIDE AREA OF RAIN
SHOWERS OVER THE NORTHEAST. WILL CONTINUE WITH LIKELY POPS
WEDNESDAY...WITH THESE LIKELY POPS CARRYING THROUGH THURSDAY.

THURSDAY AND INTO EARLY FRIDAY THIS PLAINS TROUGH WILL BEGIN TO PUSH
EASTWARD. MEANWHILE AT THE SURFACE IT WILL SPAWN A STORM SYSTEM OVER
THE CENTRAL PLAINS. MODELS CONTINUE TO TAKE THE TRACK OF THE LOW TO
OUR NORTH...WHILE BRINGING A COLD FRONT ACROSS THE REGION ON
THURSDAY. RAIN SHOWERS ALONG THE FRONT WILL TAPER OFF THURSDAY NIGHT
FOLLOWING THE PASSAGE OF THE COLD FRONT. THE AIR BEHIND THE FRONT
WILL BE COLDER...BUT NOT SUCH TO SUPPORT ANY LAKE EFFECT SNOW
RESPONSE. THERE MAY HOWEVER BE SOME LAKE EFFECT CLOUDINESS AND LIGHT
RAIN SHOWERS.

ON FRIDAY HIGH PRESSURE BEHIND THE COLD FRONT WILL MOVE INTO THE
GREAT LAKES REGION. THIS WILL END THE PRECIPITATION...WHILE ALSO
SUPPLING THE REGION WITH A FRESH COLD AIRMASS. THIS DRIER AIRMASS
MAY ALLOW FOR A MOSTLY SUNNY CHRISTMAS DAY. TEMPERATURES ALOFT WILL
LIKELY NOT BE COOL ENOUGH FOR ANY LAKE EFFECT SNOW.

IN REGARDS TO TEMPERATURES CHRISTMAS EVE...AND CHRISTMAS DAY...THE
24TH WILL BE THE WARMER OF THE TWO DAYS WITH HIGHS WELL INTO THE
50S...AND POSSIBLY 60F. FEEL COMFORTABLE WITH SURFACE TEMPERATURES
NEAR RECORD HIGHS THURSDAY AS 850 HPA TEMPERATURES OF THIS MAGNITUDE
WILL BE NEAR THE WARMEST TEMPERATURES MEASURED BY WEATHER BALLOONS
ON THIS DATE/MOVING AVERAGE...AND DESPITE THE THICK CLOUD
COVER...THE LOW SUN ANGLE HAS THE LEAST EFFECT ON DAYTIME HEATING
THIS TIME OF YEAR. A LIST OF RECORD HIGHS CAN BE FOUND IN THE
CLIMATE SECTION BELOW. ON FRIDAY BEHIND THE COLD FRONT AIR
TEMPERATURES WILL RETURN TO NEAR...ALBEIT STILL ABOVE...SEASONAL
VALUES WITH HIGHS IN THE LOW TO MID 40S.

THERE IS MODEL UNCERTAINTY AS WE HEAD INTO NEXT WEEKEND REGARDING
THE PLACEMENT OF THE NEXT UPPER LEVEL TROUGH. THE 12Z GFS MAINTAINS
A CLOSED LOW OVER THE DESERT SOUTHWEST AND EVEN INTO MEXICO...WHILE
THE 12Z ECMWF IS MORE PROGRESSIVE WITH THE FLOW...WITH A TROUGH OVER
THE SOUTHERN PLAINS. FOR NOW WILL HAVE CHANCE WORDING IN THE
FORECAST...FAVORING THE 12Z ECMWF...AS IT IS PRETTY RARE FOR A
CLOSED UPPER LEVEL LOW AT 500 HPA TO TRACK AND PERSIST AS LONG AS
THE 12Z GFS HAS OVER NORTHERN MEXICO.

&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
LAKE EFFECT SNOW HAS TAPERED OFF EAST OF LAKE ERIE AT 05Z WITH MVFR
CIGS AT KJHW. SOUTH AND SOUTHEAST OF LAKE ONTARIO...LAKE EFFECT SNOW
BANDS WILL CONTINUE THROUGH THE OVERNIGHT WITH A FEW OF THESE VERY
NARROW BANDS OF SNOW DRIFTING SOUTH ACROSS JEFFERSON COUNTY WHICH
MAY BRING TEMPO VIS/CIG REDUCTIONS AS IT SETTLE SOUTH OVERNIGHT.
LAKE EFFECT SNOW WILL DIMINISH AFTER 12Z ACROSS OSWEGO AND NORTHERN
CAYUGA COUNTIES SUNDAY WITH IMPROVEMENT TO VFR BY THE END OF THE
PERIOD.

ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST WITH CIGS RISING AS
FLOW BACKS TO THE SOUTH ON SUNDAY. STRONG WINDS WILL ALSO DIMINISH
LATE TONIGHT WITH THE ARRIVAL OF SURFACE HIGH PRESSURE AND
INCREASING WARM ADVECTION.

SUNDAY EVENING A 50KT LOW LEVEL JET WILL SHIFT OVER WESTERN NEW YORK
WITH LOW LEVEL WIND SHEAR EXPECTED. THIS HAS BEEN INCLUDED IN THE
06Z TAFS.

OUTLOOK...

MONDAY...VFR/MVFR WITH RAIN SHOWERS LIKELY.
TUESDAY...MAINLY VFR WITH A CHANCE OF RAIN SHOWERS.
WEDNESDAY AND THURSDAY...VFR/MVFR WITH RAIN SHOWERS LIKELY.

&&

.MARINE...
WINDS ON ERIE AND ONTARIO ARE ALL SUB-GALE WITH A TIGHT
PRESSURE GRADIENT BETWEEN A SURFACE HIGH BUILDING INTO THE OHIO
VALLEY AND LOW PRESSURE OVER THE CANADIAN MARITIMES. WINDS WILL
BRIEFLY SUBSIDE SUNDAY AS HIGH PRESSURE MOVES ACROSS THE LOWER GREAT
LAKES.

SOUTH-SOUTHWEST FLOW WILL THEN RE-DEVELOP ACROSS THE LOWER GREAT
LAKES MONDAY IN ADVANCE OF A COLD FRONT THAT WILL CROSS THE LAKES
MONDAY. THIS WILL EVENTUALLY REQUIRE ANOTHER ROUND OF SMALL CRAFT
ADVISORIES FOR THE EASTERN ENDS OF THE LAKES.

&&

.CLIMATE...
ALTHOUGH BUFFALO HAS GOTTEN ITS FIRST MEASURABLE SNOW...THIS
WINTER CONTINUES TO BE OFF TO AN EXTRAORDINARLY WARM START.

MORE UNSEASONABLE WARMTH EXPECTED NEXT WEEK. ANOTHER VERY WARM
AIRMASS WILL BRING NEAR RECORD HIGHS ON WEDNESDAY AND THURSDAY
(CHRISTMAS EVE). LISTED BELOW ARE THE RECORDS...

WEDNESDAY...

CITY.........RECORD HIGH (F)....RECORD WARM LOW (F).....

BUFFALO......59 / 1957...........46 / 1941
ROCHESTER....60 / 1957...........43 / 2006
WATERTOWN....58 / 1990...........42 / 2006

CHRISTMAS EVE...

BUFFALO......59 / 1964...........46 / 1979
ROCHESTER....58 / 1982...........47 / 2014
WATERTOWN....59 / 2014...........49 / 2014

WHEN CONSIDERING THE FORECAST THROUGH THE END OF THE MONTH...2015
STANDS A GOOD CHANCE TO BECOME THE WARMEST ON RECORD. CURRENT
TRENDS SUGGEST THAT THE MONTHLY AVERAGE TEMPERATURE MAY TOP 40
DEGREES. THIS PUTS THE FOLLOWING RECORDS IN SERIOUS JEOPARDY.

WARMEST MEAN TEMPERATURE FOR DECEMBER...

CITY        TEMP YEAR
BUFFALO.....37.6 (1923)
ROCHESTER...39.0 (2006)

&&

.EQUIPMENT...
THE BUF WSR-88D HAS AGAIN BEEN WORKED ON AND IS OPERATING.
HOWEVER THERE ARE STILL SPORADIC ISSUES WHICH MAY IMPACT DATA
QUALITY AND TIMELINESS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR
     NYZ006-008.
     LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR
     NYZ005.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON
         FOR LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
         LOZ042.

&&

$$

SYNOPSIS...SMITH/WOOD
NEAR TERM...SMITH/WOOD
SHORT TERM...THOMAS
LONG TERM...APFFEL/THOMAS
AVIATION...SMITH/WOOD
MARINE...SMITH/WOOD
CLIMATE...THOMAS/APFFEL
EQUIPMENT...THOMAS




AREA FORECAST DISCUSSION

NWS RALEIGH NC

 756 PM EST MON DEC 21 2015

.SYNOPSIS... A SOUTHERLY FLOW OF WARMER AND MORE MOIST AIR WILL
DEVELOP TODAY AND PERSIST FOR MUCH OF THE WEEK. MEANWHILE...A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY...THEN STALL
OVER THE REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 PM MONDAY...

WARM ADVECTION...AHEAD OF A COLD FRONT IN THE MISSISSIPPI VALLEY
REGION...CONTINUES ACROSS THE SOUTHEAST US IN DEEP SOUTHEASTERLY
FLOW.  A LIGHT BAND OF RAIN ASSOCIATED WITH A NARROW REGION OF 700MB
MOISTURE JUST WEST OF THE TRIAD MAY PRODUCE SOME VERY LIGHT RAIN
THIS AFTERNOON...BUT THE LOW-LEVELS ARE STILL RATHER DRY AND ITS
TAKING SOME TIME FOR THE PRECIP TO REACH THE GROUND.  THUS...A LARGE
MAJORITY OF THE CWA WILL BE DRY THIS EVENING.  MODELS SHOW A LARGE
AREA OF RAIN BREAKING OUT OUT OVER GA/AL THIS EVENING AND SPREADING
NORTHEAST INTO THE CAROLINAS AFTER MIDNIGHT AS A SHORTWAVE PASSES TO
OUR NORTHWEST AND A LOW LEVEL JET INCREASES THE ISENTROPIC LIFT/WARM
OVER OUR REGION. THE HRRR SHOWS THE PRECIP MOVING INTO THE
SOUTHERN/WESTERN PIEDMONT AROUND 08Z. THIS IS GENERALLY IN AGREEMENT
WITH THE LARGE SCALE MODELS...WHICH SHOW THE HEAVIEST RAINFALL
AMOUNTS...0.50-0.75"...ACROSS THE SOUTHERN PIEDMONT THROUGH 12Z
TUESDAY.  PW WILL BE INCREASING TO WELL OVER 1.5"...SO SOME OF THE
RAIN COULD BE LOCALLY HEAVIER...BUT INSTABILITY LOOKS VERY MEAGER
WITH WEAK LAPSE RATES ALOFT DESPITE THE WARM ADVECTION AND LOW LEVEL
JETTING. WITH DEWPOINTS RECOVERING AHEAD OF THE PRECIP TONIGHT...
LOWS SHOULD END UP IN THE MID 40S NORTHWEST TO MID 50S.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 305 PM MONDAY...

ONGOING SHOWERS WILL SHIFT NORTH AND EAST TUESDAY MORNING AS THE LOW
LEVEL JET SURGES OFF TO THE NORTHEAST. BUFR SOUNDINGS SHOW SOME
MARKEDLY DRIER MID-LEVEL AIR THAT SHOULD RENDER MUCH OF THE AIR FREE
OF PRECIP BY TUESDAY AFTERNOON...ALTHOUGH SHALLOW ISENTROPIC LIFT
COULD STILL SUPPORT SOME DRIZZLE ACROSS THE WESTERN PIEDMONT. THIS
FORECAST WILL DRASTICALLY CUT BACK POPS AFTER 18Z...AND CHANCE POPS
MAY STILL BE TOO HIGH.  ALL GUIDANCE GIVES HIGHS IN THE 60S BY
TUESDAY AFTERNOON...BUT GIVEN THAT THERE WILL BE NO AIRMASS CHANGE
AFTER THE PRECIPITATION TONIGHT...ITS KINDA HARD TO UNDERSTAND THE
NORTHWEST PIEDMONT REACHING 60.  MET GUIDANCE IS ONE OF THE ONLY
MODELS TO GIVE UPPER 50S...SO WILL GO WITH UPPER 50S NORTHWEST TO
NEAR 70 SOUTHEAST.

ANOTHER ROUND OF PRECIP WILL BE HEADING OUT EAST TUESDAY NIGHT AS A
DEEPER TROUGH MOVES THROUGH THE CENTRAL US AND THE LOW LEVEL
JET/WARM ADVECTION INTENSIFY OVER THE SOUTHEAST US ONCE AGAIN. THE
PREFERRED GFS AND ECMWF TAKE THE HEAVIEST QPF THROUGH THE MOUNTAINS
AS THE LOW LEVEL FLOW BACKS AROUND TO MORE SOUTHEASTERLY...BUT WITH
PW STILL WELL ABOVE NORMAL AND STRONG WARM ADVECTION...WILL CARRY
LIKELY POPS AFTER 00Z AND CATEGORICAL ACROSS THE WEST.  THE
PROBABILITY THUNDER STILL LOOKS LOW GIVEN WEAK LAPSE RATES..THOUGH
THE CHANCE MAY BE SLIGHTLY HIGHER THAN TONIGHT WITH A STRONGER LOW
LEVEL JET.  IT STILL LOOKS TOO ISOLATED TO INCLUDE IN THE FORECAST
FOR NOW.  LOWS WILL BE MILDER IN THE UPPER 60S TO LOWER 70S.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 1055 AM MONDAY...

...WIDESPREAD RAIN WED INTO WED NIGHT...
...ABOVE NORMAL TEMPS TO PERSIST THROUGH THE WEEKEND...

WED/THU: SHORTWAVE ENERGY DIVING SOUTHEAST THROUGH THE PACIFIC NW
AND NORTHERN CA TONIGHT WILL AMPLIFY A LONGWAVE TROUGH OVER THE
INTERMOUNTAIN WEST AND DESERT SW ON TUE. CYCLOGENESIS WILL OCCUR
OVER THE CENTRAL PLAINS TUE NIGHT AS THE AMPLIFYING TROUGH
PROGRESSES ACROSS THE ROCKIES. AN ENERGETIC SFC CYCLONE WILL
ACCOMPANY THE UPPER TROUGH AS IT LIFTS NORTHEAST THROUGH THE
NORTHERN GREAT LAKES ON WED AND INTO CANADA WED NIGHT. DOWNSTREAM
ACROSS THE SOUTHEAST...SOUTHERLY LOW-LEVEL FLOW EMANATING FROM THE
GOMEX WILL STRENGTHEN IN CONCERT WITH STRENGTHENING SW FLOW ALOFT
AND TRANSPORT AN UNSEASONABLY MOIST AIRMASS INTO THE CAROLINAS (PWAT
VALUES > 1.50" AND SFC DEWPOINTS IN THE 60S TO NEAR 70F). GIVEN WELL
ABOVE NORMAL MOISTURE IN THE PRESENCE OF BROAD WARM ADVECTION AND
OCCASIONAL BOUTS OF DPVA ATTENDANT SMALL AMPLITUDE WAVES IN SW FLOW
ALOFT...EXPECT WIDESPREAD MODERATE TO OCCASIONALLY HEAVY RAIN WED
INTO WED NIGHT...WITH PRECIP AMOUNTS ~1.00" (LOCALLY HIGHER AMOUNTS
IN NW PIEDMONT). 1000-850 MB THICKNESSES SUPPORT ABOVE NORMAL
TEMPERATURES WED/THU. CLOUD COVER AND RAIN WILL HELP MODERATE TEMPS
ON WED (UPPER 60S TO LOWER 70S)...THOUGH LESS SO ON THU (MID/UPPER
70S) AS THE BEST WARM ADVECTION SHIFTS NORTH INTO THE MID-ATLANTIC
AND PRECIP CHANCES DIMINISH TO ISOLD/SCT DIURNAL SHOWERS. AT THIS
TIME DO NOT ANTICIPATE A CHANCE FOR THUNDER GIVEN MOIST-ADIABATIC
THERMAL PROFILES AND NO SIGNIFICANT FORCING...PARTICULARLY W/REGARD
TO DPVA/LAYER-LIFTING. DESPITE A LACK OF THUNDER...TIGHTENING OF THE
LOW-LEVEL HEIGHT/MSLP GRADIENT MAY YIELD GUSTY SOUTHWEST WINDS WED
AFTERNOON AND AGAIN ON THU...WITH WIND GUSTS UP TO ~45 MPH POSSIBLE
IN HEAVIER CONVECTION.

FRI-MON: THE COLD FRONT ASSOC/W THE UPPER LEVEL TROUGH AND ATTENDANT
SFC CYCLONE RAPIDLY PROGRESSING INTO CANADA WILL RAPIDLY WEAKEN AS
IT PROGRESSES EAST OF THE APPALACHIANS...BECOMING WSW-ENE ORIENTED
BEFORE STALLING IN VICINITY OF THE CAROLINA/SOUTHEAST COAST FRI.
LONG RANGE GUIDANCE DIVERGES SUBSTANTIALLY SAT-MON...APPARENTLY AS A
RESULT OF UNCERTAINTY IN THE EVOLUTION OF A POTENT UPPER LEVEL WAVE
(MOVING ASHORE THE NORTHERN CA/PACIFIC COAST FRI) EXPECTED TO
AMPLIFY INTO A CLOSED LOW OVER SOUTHERN CA AND THE DESERT SW THIS
WEEKEND BEFORE PROGRESSING SLOWLY EAST/NE INTO PORTIONS OF THE
CENTRAL CONUS BY EARLY NEXT WEEK. WITH THE ABOVE IN MIND...EXPECT
ABOVE NORMAL TEMPERATURES (TEMPERED BY BROKEN TO OVERCAST CLOUD
COVER) TO PERSIST OVER THE WEEKEND WITH VERY LITTLE POTENTIAL FOR
PRECIPITATION ASIDE FROM A FEW SPRINKLES OR AN OCCASIONAL SHOWER.
FORECAST UNCERTAINTY INCREASES DRAMATICALLY BY EARLY NEXT WEEK...
THOUGH PRECIP CHANCES SHOULD GENERALLY INCREASE FROM WEST-EAST
MON/TUE AS A COLD FRONT APPROACHES FROM THE WEST. -VINCENT


&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 740 PM MONDAY...

24 HOUR TAF PERIOD: VFR CONDITIONS THIS EVENING WILL GIVEN WAY
OVERNIGHT INTO TUESDAY TO RAIN AND IFR/LIFR CONDITIONS... AS A COLD
FRONT SLOWLY APPROACHES THE REGION FROM THE WEST. WE MAY SEE SOME
IMPROVEMENT IN CIGS BY TUESDAY AFTERNOON... ESPECIALLY AT THE
EASTERN TAF SITES (KRWI AND KFAY)... AS THE MAIN AREA OF RAIN BEGINS
TO SHIFT TO THE EAST. WHILE CONFIDENCE IN SUB-VFR CONDITIONS
OVERNIGHT INTO TUESDAY MORNING IS HIGH... CONFIDENCE IS LOW IN HOW
FAST CIGS WILL BEGIN TO IMPROVE.

OUTLOOK: A TUMULTUOUS PERIOD FOR AVIATION CONDITIONS AS A SLUG OF
MOISTURE MOVES OUT OF THE GULF OF MEXICO AND OVER THE SOUTHEASTERN
CONUS...WHICH COULD POTENTIALLY PRODUCE SEVERAL EXTENDED PERIODS OF
RAIN THROUGH THE WEEK AND INTO THE WEEKEND.

&&

.CLIMATE...

HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1899.

DEC 24:       RECORD MAXIMUM   HIGH MINIMUM
GREENSBORO    71 (1964)        52 (1904)
RALEIGH       75 (1931)        59 (1891)
FAYETTEVILLE  78 (1931)        66 (1990)

DEC 25:       RECORD MAXIMUM   HIGH MINIMUM
GREENSBORO    74 (1955)        58 (1932)
RALEIGH       75 (1955)        63 (1932)
FAYETTEVILLE  79 (1932)        68 (1932)

&&

.RAH WATCHES/WARNINGS/ADVISORIES... NONE.

&&

$$

SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22
LONG TERM...VINCENT
AVIATION...77/22
CLIMATE...HARTFIELD/BLAES




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1003 PM CST MON DEC 21 2015

.UPDATE...
ISSUED AT 951 PM CST MON DEC 21 2015

NO SIGNIFICANT UPDATES FOR THE LATE EVENING FORECAST. ISSUED A SPS
FOR FOG ALONG THE WESTERN EDGE OF STRATUS ACROSS SOUTH CENTRAL
NORTH DAKOTA. THIS IS MAINLY ALONG THE MISSOURI RIVER FROM THE
SOUTH DAKOTA BORDER TO LAKE SAKAKAWEA. SINCE THE ISSUANCE SOME OF
THE ASOS/AWOS OBSERVATIONS HAVE IMPROVED A LITTLE AS WARM
ADVECTION AND CLOUDS CONTINUE TO INCREASE FROM WEST TO EAST. WILL
CONTINUE TO MONITOR BUT FOR NOW WILL CONTINUE WITH AN SPS AND NOT
ISSUE A DENSE FOG ADVISORY.

TEMPERATURES CONTINUE TO BE AN ISSUE WITH SOME CLEAR SPOTS...BUT
AS STRATUS SPREADS NORTH AND MID-HIGH CLOUDS INCREASE FROM THE
WEST...WE SHOULD SEE TEMPERATURES STEADY...AND MAYBE RISE A BIT.

AS FAR AS SNOWFALL...HAVE DELAYED THE ARRIVAL OF PRECIPITATION BY
A COUPLE HOURS. LATEST ITERATIONS OF THE MESOSCALE MODELS ARE
ACTUALLY PRETTY SIMILAR TO THE PREVIOUS FORECAST...WITH THE SLIGHT
DELAY IN ONSET. NO SIGNIFICANT CHANGES TO THE OVERALL SNOW
FORECAST AS MODELS ARE JUST ROLLING IN...BUT SEE NOTHING AT THIS
TIME INDICATING A SIGNIFICANT CHANGE FROM OUR CURRENT ADVISORY.

UPDATE ISSUED AT 645 PM CST MON DEC 21 2015

MAIN FORECAST PROBLEM FOR THIS EVENING WILL ONCE AGAIN BE
TEMPERATURES AND CLOUDS/FOG.

CURRENTLY...MAINLY CLEAR SKIES ACROSS WESTERN NORTH DAKOTA.
WIDESPREAD STRATUS OVER THE SOUTH CENTRAL FROM AROUND BISMARCK AND
FORT YATES EAST TO THE JAMES RIVER VALLEY...EXCEPT FOR A HOLE THAT
INCLUDES THE KJMS TAF. STRATUS HAS LIFTED ACROSS MOST OF THE NORTH
CENTRAL BUT A FEW PATCHES REMAIN AROUND THE TURTLE MOUNTAINS.
THINK THESE AREAS ACROSS CENTRAL NORTH DAKOTA WILL LIKELY FILL IN
THIS EVENING. ACROSS THE WEST SKIES MAY REMAIN CLEAR UNTIL HIGHER
CLOUDS ASSOCIATED WITH THE NEXT SYSTEM APPROACH BY MID TO LATE
EVENING. THIS WOULD ALLOW TEMPERATURES TO FALL A LITTLE MORE THAN
ORIGINALLY FORECAST. WILL ADJUST SKY BASED ON LATEST SATELLITE
ANALYSIS AND EXPECTATION FROM MESOSCALE MODELS THAT CENTRAL ND
WILL LIKELY CLOUD UP AGAIN WITH STRATUS DURING THE EVENING. WILL
NEED TO LOWER TEMPERATURES A BIT IN THE FAR EAST WHERE
TEMPERATURES ARE ALREADY NEAR FORECAST LOWS...BUT WITH STRATUS IN
PLACE MANY AREAS...WON`T LET THEM DROP TOO MUCH. WILL LIKELY LOWER
TEMPERATURES A LITTLE IN THE WEST AS EVEN THOUGH WARM ADVECTION
AND CLOUDS WILL INCREASE LATER...SHOULD BE A FEW HOURS WITH CLEAR
SKIES AND LIGHT WINDS BEFORE THIS BEGINS IN EARNEST.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

FOG TONIGHT AND ACCUMULATING SNOW TUESDAY HIGHLIGHT THE SHORT TERM
FORECAST.

THE 15-19 UTC HRRR ITERATIONS AND THE 12 UTC NAM NEST ONCE AGAIN
TONIGHT DEPICT FOG DEVELOPMENT WITHIN THEIR RESPECTIVE VISIBILITY
FIELDS. THESE FORECASTS HAVE PERFORMED WELL THE PAST WEEK IN
SIGNALING FOG...AND WILL FOLLOW THEIR SOLUTIONS WHICH SUGGEST FOG
GENERALLY ALONG AND EAST OF HIGHWAY 83 TONIGHT INTO EARLY TUESDAY
MORNING BEFORE THE SNOWFALL. A DENSE FOG ADVISORY MAY BE
POSSIBLE.

FOR TUESDAY...THE 12 UTC AND INCOMING 18 UTC DETERMINISTIC AND
ENSEMBLE SUITES ARE IN AGREEMENT ON A WAVE EJECTING NORTHEAST OUT
OF WYOMING...DEEPENING AND POTENTIALLY CLOSING OFF AS IT
PROPAGATES ACROSS NORTH DAKOTA. STRONG FRONTOGENETIC FORCING AND
VERTICAL MOTION IN THE DENDRITIC GROWTH LAYER ARE EXPECTED ALONG
AND NORTH OF THE 700 MB LOW TRACK FROM SOUTHWEST THROUGH NORTHEAST
NORTH DAKOTA TO SUPPORT MESOSCALE BANDING OF SNOW. THE GREATEST
SNOWFALL AMOUNTS OF 3 TO 5 INCHES ARE FORECAST ACROSS THE FAR
NORTH CENTRAL AND TURTLE MOUNTAINS WHERE SNOWFALL DURATION WILL BE
THE LONGEST IN ASSOCIATION WITH THE DEVELOPING TROWAL. THUS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. FOR NOW...THE
LACK OF STRONG ELEVATED INSTABILITY IS EXPECTED TO KEEP SNOWFALL
AMOUNTS BELOW WARNING LEVELS. HOWEVER...THIS WILL HAVE TO BE
CLOSELY MONITORED IN THE MODEL SOLUTIONS OVER THE NEXT 12 HOURS.
ELSEWHERE...WIDESPREAD ONE TO THREE INCH SNOWFALL AMOUNTS ARE
EXPECTED.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

SURFACE LOW AND ASSOCIATED MID/UPPER LEVEL TROUGH WILL EXIT THE
TURTLE MOUNTAINS AND SHIFT INTO SOUTHERN ONTARIO BY 12Z WEDNESDAY.
SNOW WILL GRADUALLY DIMINISH AND END TUESDAY NIGHT WITH A COLD
POCKET/THERMAL TROUGH LINGERING THROUGH WEDNESDAY. THIS WILL RESULT
IN PLENTY OF CLOUDS AND POSSIBLE FLURRIES WEDNESDAY. ANOTHER WEAK
SHORTWAVE IS EXPECTED THURSDAY AFTERNOON/EVENING...BUT ANY
PRECIPITATION THREAT IS VERY MINIMAL. A SPLIT FLOW DEVELOPS FOR
THE REST OF THE EXTENDED PERIOD AS AN UPPER TROUGH/LOW IS CARVED
OUT IN THE SOUTHWEST. NORTH DAKOTA FALLS UNDER A SOUTHWEST FLOW
ALOFT CHRISTMAS DAY/FRIDAY...WITH A DEFORMATION ZONE EVOLVING
ACROSS SOUTHERN NORTH DAKOTA FRIDAY NIGHT INTO SATURDAY MORNING.
CHRISTMAS DAY REMAINS DRY WITH MOISTURE ADVECTION INCREASING
FRIDAY EVENING FAR SOUTH. THIS IS IN RESPONSE TO AN INITIAL
MID/UPPER LEVEL LOW EJECTING FROM THE SOUTHWEST UPPER TROUGH WILL
SLIDE ACROSS SOUTH DAKOTA DURING THE ABOVE TIME. WILL CONTINUE TO
WATCH THE TRACK BUT AS OF NOW SOME LIGHT SNOW IS EXPECTED SOUTH OF
I-94 DURING THIS TIME. THIS SHORTWAVE DEPARTS SATURDAY NIGHT WITH
DRY WEATHER UNTIL AT LEAST MONDAY. HIGHS WILL REMAINING IN THE 20S
WED/THU...THEN COLDER AIR WILL BE DRAWN INTO THE APPROACHING
SOUTHWEST SYSTEM WITH WINDS BECOMING NORTH TO NORTHEAST FRI/SAT.
AS THE SYSTEM DEPARTS AND WINDS BECOME SOUTHWEST...HIGHS WILL ONCE
AGAIN REBOUND INTO THE 20S SUNDAY AND MONDAY. OVERNIGHT LOWS WILL
BE COLDEST FRIDAY MORNING THROUGH SUNDAY MORNING WITH LOWS 5 BELOW
ZERO NORTH TO 5 ABOVE ZERO SOUTH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 951 PM CST MON DEC 21 2015

AREAS OF MVFR-IFR STRATUS EXPECTED ACROSS CENTRAL NORTH DAKOTA
TONIGHT. VFR CONDITIONS WEST THIS EVENING...THEN INCREASING CLOUDS
WITH AN APPROACHING SMALL BUT POTENT LOW PRESSURE SYSTEM. THIS
SYSTEM WILL BRING MVFR-IFR CEILINGS AND VISIBILITIES IN SNOW AND
FOG FROM MAINLY KBIS NORTH AND EAST TO KMOT AND KJMS BEGINNING
AROUND 12 UTC AT KBIS. WHEN THIS SYSTEM EXITS IN THE AFTERNOON
TUESDAY...LOW STRATUS AND POTENTIAL FOR FOG WILL REMAIN.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM TUESDAY TO MIDNIGHT CST
TUESDAY NIGHT FOR NDZ005-012-013-022-023-025.

&&

$$

UPDATE...TWH
SHORT TERM...AYD
LONG TERM...KS
AVIATION...TWH




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 656 PM CST MON DEC 21 2015

.UPDATE...
ISSUED AT 645 PM CST MON DEC 21 2015

MAIN FORECAST PROBLEM FOR THIS EVENING WILL ONCE AGAIN BE
TEMPERATURES AND CLOUDS/FOG.

CURRENTLY...MAINLY CLEAR SKIES ACROSS WESTERN NORTH DAKOTA.
WIDESPREAD STRATUS OVER THE SOUTH CENTRAL FROM AROUND BISMARCK AND
FORT YATES EAST TO THE JAMES RIVER VALLEY...EXCEPT FOR A HOLE THAT
INCLUDES THE KJMS TAF. STRATUS HAS LIFTED ACROSS MOST OF THE NORTH
CENTRAL BUT A FEW PATCHES REMAIN AROUND THE TURTLE MOUNTAINS.
THINK THESE AREAS ACROSS CENTRAL NORTH DAKOTA WILL LIKELY FILL IN
THIS EVENING. ACROSS THE WEST SKIES MAY REMAIN CLEAR UNTIL HIGHER
CLOUDS ASSOCIATED WITH THE NEXT SYSTEM APPROACH BY MID TO LATE
EVENING. THIS WOULD ALLOW TEMPERATURES TO FALL A LITTLE MORE THAN
ORIGINALLY FORECAST. WILL ADJUST SKY BASED ON LATEST SATELLITE
ANALYSIS AND EXPECTATION FROM MESOSCALE MODELS THAT CENTRAL ND
WILL LIKELY CLOUD UP AGAIN WITH STRATUS DURING THE EVENING. WILL
NEED TO LOWER TEMPERATURES A BIT IN THE FAR EAST WHERE
TEMPERATURES ARE ALREADY NEAR FORECAST LOWS...BUT WITH STRATUS IN
PLACE MANY AREAS...WON`T LET THEM DROP TOO MUCH. WILL LIKELY LOWER
TEMPERATURES A LITTLE IN THE WEST AS EVEN THOUGH WARM ADVECTION
AND CLOUDS WILL INCREASE LATER...SHOULD BE A FEW HOURS WITH CLEAR
SKIES AND LIGHT WINDS BEFORE THIS BEGINS IN EARNEST.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

FOG TONIGHT AND ACCUMULATING SNOW TUESDAY HIGHLIGHT THE SHORT TERM
FORECAST.

THE 15-19 UTC HRRR ITERATIONS AND THE 12 UTC NAM NEST ONCE AGAIN
TONIGHT DEPICT FOG DEVELOPMENT WITHIN THEIR RESPECTIVE VISIBILITY
FIELDS. THESE FORECASTS HAVE PERFORMED WELL THE PAST WEEK IN
SIGNALING FOG...AND WILL FOLLOW THEIR SOLUTIONS WHICH SUGGEST FOG
GENERALLY ALONG AND EAST OF HIGHWAY 83 TONIGHT INTO EARLY TUESDAY
MORNING BEFORE THE SNOWFALL. A DENSE FOG ADVISORY MAY BE
POSSIBLE.

FOR TUESDAY...THE 12 UTC AND INCOMING 18 UTC DETERMINISTIC AND
ENSEMBLE SUITES ARE IN AGREEMENT ON A WAVE EJECTING NORTHEAST OUT
OF WYOMING...DEEPENING AND POTENTIALLY CLOSING OFF AS IT
PROPAGATES ACROSS NORTH DAKOTA. STRONG FRONTOGENETIC FORCING AND
VERTICAL MOTION IN THE DENDRITIC GROWTH LAYER ARE EXPECTED ALONG
AND NORTH OF THE 700 MB LOW TRACK FROM SOUTHWEST THROUGH NORTHEAST
NORTH DAKOTA TO SUPPORT MESOSCALE BANDING OF SNOW. THE GREATEST
SNOWFALL AMOUNTS OF 3 TO 5 INCHES ARE FORECAST ACROSS THE FAR
NORTH CENTRAL AND TURTLE MOUNTAINS WHERE SNOWFALL DURATION WILL BE
THE LONGEST IN ASSOCIATION WITH THE DEVELOPING TROWAL. THUS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. FOR NOW...THE
LACK OF STRONG ELEVATED INSTABILITY IS EXPECTED TO KEEP SNOWFALL
AMOUNTS BELOW WARNING LEVELS. HOWEVER...THIS WILL HAVE TO BE
CLOSELY MONITORED IN THE MODEL SOLUTIONS OVER THE NEXT 12 HOURS.
ELSEWHERE...WIDESPREAD ONE TO THREE INCH SNOWFALL AMOUNTS ARE
EXPECTED.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

SURFACE LOW AND ASSOCIATED MID/UPPER LEVEL TROUGH WILL EXIT THE
TURTLE MOUNTAINS AND SHIFT INTO SOUTHERN ONTARIO BY 12Z WEDNESDAY.
SNOW WILL GRADUALLY DIMINISH AND END TUESDAY NIGHT WITH A COLD
POCKET/THERMAL TROUGH LINGERING THROUGH WEDNESDAY. THIS WILL RESULT
IN PLENTY OF CLOUDS AND POSSIBLE FLURRIES WEDNESDAY. ANOTHER WEAK
SHORTWAVE IS EXPECTED THURSDAY AFTERNOON/EVENING...BUT ANY
PRECIPITATION THREAT IS VERY MINIMAL. A SPLIT FLOW DEVELOPS FOR
THE REST OF THE EXTENDED PERIOD AS AN UPPER TROUGH/LOW IS CARVED
OUT IN THE SOUTHWEST. NORTH DAKOTA FALLS UNDER A SOUTHWEST FLOW
ALOFT CHRISTMAS DAY/FRIDAY...WITH A DEFORMATION ZONE EVOLVING
ACROSS SOUTHERN NORTH DAKOTA FRIDAY NIGHT INTO SATURDAY MORNING.
CHRISTMAS DAY REMAINS DRY WITH MOISTURE ADVECTION INCREASING
FRIDAY EVENING FAR SOUTH. THIS IS IN RESPONSE TO AN INITIAL
MID/UPPER LEVEL LOW EJECTING FROM THE SOUTHWEST UPPER TROUGH WILL
SLIDE ACROSS SOUTH DAKOTA DURING THE ABOVE TIME. WILL CONTINUE TO
WATCH THE TRACK BUT AS OF NOW SOME LIGHT SNOW IS EXPECTED SOUTH OF
I-94 DURING THIS TIME. THIS SHORTWAVE DEPARTS SATURDAY NIGHT WITH
DRY WEATHER UNTIL AT LEAST MONDAY. HIGHS WILL REMAINING IN THE 20S
WED/THU...THEN COLDER AIR WILL BE DRAWN INTO THE APPROACHING
SOUTHWEST SYSTEM WITH WINDS BECOMING NORTH TO NORTHEAST FRI/SAT.
AS THE SYSTEM DEPARTS AND WINDS BECOME SOUTHWEST...HIGHS WILL ONCE
AGAIN REBOUND INTO THE 20S SUNDAY AND MONDAY. OVERNIGHT LOWS WILL
BE COLDEST FRIDAY MORNING THROUGH SUNDAY MORNING WITH LOWS 5 BELOW
ZERO NORTH TO 5 ABOVE ZERO SOUTH.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 645 PM CST MON DEC 21 2015

AREAS OF MVFR-IFR STRATUS EXPECTED ACROSS CENTRAL NORTH DAKOTA
TONIGHT. VFR CONDITIONS WEST THIS EVENING...THEN INCREASING CLOUDS
WITH AN APPROACHING SMALL BUT POTENT LOW PRESSURE SYSTEM. THIS
SYSTEM WILL BRING MVFR-IFR CEILINGS AND VISIBILITIES IN SNOW AND
FOG FROM MAINLY KBIS NORTH AND EAST TO KMOT AND KJMS BEGINNING
AROUND 12 UTC AT KBIS. WHEN THIS SYSTEM EXITS IN THE AFTERNOON
TUESDAY...LOW STRATUS AND POTENTIAL FOR FOG WILL REMAIN.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM TUESDAY TO MIDNIGHT CST
TUESDAY NIGHT FOR NDZ005-012-013-022-023-025.

&&

$$

UPDATE...TWH
SHORT TERM...AYD
LONG TERM...KS
AVIATION...TWH



AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1249 PM CST SUN DEC 20 2015

.UPDATE...
ISSUED AT 1241 PM CST SUN DEC 20 2015

EXTENDED THE DENSE FOG ADVISORY THROUGH 00 UTC ACROSS NORTHWEST
NORTH DAKOTA PER OBSERVATIONAL TRENDS THROUGH 18 UTC AND THE 16-17
UTC HRRR ITERATION VISIBILITY FORECASTS. CERTAINLY POSSIBLE THAT
THE ADVISORY MAY NEED TO BE EXPANDED IN TIME AND OR AREA THROUGH
THE EVENING AND OVERNIGHT AS CURRENT STRATUS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA IS EXPECTED TO BUILD DOWN POTENTIALLY INTO
FOG.

UPDATE ISSUED AT 915 AM CST SUN DEC 20 2015

QUICK UPDATE TO ISSUE A DENSE FOG ADVISORY FOR NORTHWEST NORTH
DAKOTA THROUGH 19 UTC GIVEN WEBCAM AND SURFACE OBSERVATION TRENDS
THROUGH 15 UTC...AND A NEAR MINIMUM SOLAR ANGLE LIMITING
INSOLATION TO LIFT THE FOG POST SUNRISE.

UPDATE ISSUED AT 845 AM CST SUN DEC 20 2015

OVER THE PAST TWO HOURS THROUGH 1445 UTC...VISIBILITY HAS
CONTINUED TO DECREASE IN FOG ACROSS WESTERN NORTH DAKOTA PER
WEBCAM AND SURFACE OBSERVATIONS...WITH LOCALLY DENSE FOG IN SOME
AREAS. WILL CONTINUE TO MONITOR TRENDS THIS MORNING SHOULD A DENSE
FOG ADVISORY BECOME NECESSARY...AS THE 12-13 UTC HRRR AND 06 UTC
NAM NEST SUGGEST FOG MAY CONTINUE TO EXPAND THROUGH THE MORNING.

UPDATE ISSUED AT 609 AM CST SUN DEC 20 2015

SOME LIGHT SNOW HAS DEVELOPED STRETCHING FROM SOUTHWEST TOWARDS
THE NORTHEAST ACROSS THE STATE WHICH HIGH-RES MODELS ARE NOT
PICKING UP TO WELL. FOR MORNING UPDATES HAVE ADDED POPS TO THE
FORECAST TO ADDRESS THIS. EXPECT THIS SNOW TO DIMINISH BY MID-DAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN DEC 20 2015

MAIN CHALLENGE IN THE SHORT TERM IS CLOUD COVER AND FOG POTENTIAL.

CURRENTLY...AT THE SURFACE...COOL HIGH PRESSURE WAS CENTERED OVER
HUDSON BAY WITH A RIDGE AXIS EXTENDING SOUTHWEST INTO SASKATCHEWAN.
THE BOUNDARY BETWEEN THIS COOL HIGH PRESSURE AND MILDER AIR TO THE
SOUTH WAS A WEAK LOW PRESSURE FRONT ACROSS FAR SOUTHERN
SASKATCHEWAN. AT UPPER LEVELS...A LONGWAVE TROUGH EXTENDED OVER THE
EASTERN ROCKIES AND WAS POISED TO EMERGE INTO THE FRONT RANGE.

THE UPPER LEVEL TROUGH IS FORECAST TO MOVE EAST ACROSS THE DAKOTAS
TODAY AND TONIGHT...BUT THE BASE OF THE TROUGH IS FORECAST TO DEEPEN
NEAR THE 4-CORNERS AREA TODAY AND DEVELOP A STRONGER SHORTWAVE. THIS
WILL WEAKEN THE TROUGHING FARTHER NORTH AND KEEP ANY FORCING FARTHER
TO THE SOUTH OF NORTH DAKOTA TODAY. MEANWHILE THE SURFACE BOUNDARY
IN SOUTHERN SASKATCHEWAN IS FORECAST TO DROP SOUTH ACROSS THE STATE
THIS MORNING...BRINGING WITH IT THE COOLER AND MOIST AIR OF THE
CANADIAN HIGH. SKIES SHOULD REMAIN CLOUDY OVER THE STATE WITH SOME
PATCHY FOG THIS MORNING. THE AXIS OF THE SURFACE HIGH IS FORECAST TO
MOVE SOUTHEAST AND EXTEND FROM MANITOBA ACROSS THE EASTERN DAKOTAS
BY EVENING...WITH THE COOL HIGH PRESSURE RIDGE AXIS REMAINING OVER
THE EASTERN DAKOTAS SUNDAY NIGHT. WHILE CLOUDS MAY DECREASE A BIT IN
THE WEST THIS AFTERNOON...CLOUDS WILL LIKELY INCREASE IN THE WESTERN
PART OF THE STATE TONIGHT AS THE COOL HIGH PRESSURE MOVES EAST AND A
DEVELOPING TROUGH IN THE FRONT RANGE BRINGS SOME WARM ADVECTION AND
VERTICAL MOTION TO WESTERN NORTH DAKOTA.

HIGHS TODAY ARE EXPECTED TO BE IN THE TEENS TO LOWER 20S OVER
NORTHERN AND CENTRAL PARTS OF THE STATE...WITH UPPER 20S AND LOWER
30S IN THE SOUTHWEST. MINIMUM TEMPERATURES SUNDAY NIGHT SHOULD RANGE
FROM 5 TO 10 ABOVE OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA -
CLOSER TO THE COOL RIDGE AXIS - TO THE TEENS IN THE WEST.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN DEC 20 2015

HIGHLIGHT FOR THE EXTENDED PERIOD WILL BE THE OCCASIONAL SNOW
CHANCES AS VARIOUS SHORT WAVES SLIDE THROUGH THE AREA WHILE
TEMPERATURES REMAIN SEASONAL.

ON MONDAY...FAST MOVING SHORT WAVE ZIPS THROUGH THE AREA BRINGING
CHANCES FOR LIGHT SNOW AS IT MOVES THROUGH. ANY ACCUMULATIONS
WILL BE MINIMAL.

FOR TUESDAY...A STRONGER SHORT WAVE PUSHES INTO THE REGION AS A
SURFACE LOW LIFTS THROUGH THE DAKOTAS. THIS WILL BRING INCREASING
SNOW CHANCES OVER NORTHERN AND EASTERN LOCATIONS...WITH THE
GREATEST CHANCES OVER NORTH CENTRAL NORTH DAKOTA WHERE AN INCH OR
TWO OF NEW SNOW WILL BE POSSIBLE. LOW CHANCES FOR SNOW LINGER INTO
WEDNESDAY.

MAINLY QUIET WEATHER EXPECTED ON THURSDAY. GOING INTO THE HOLIDAY
WEEKEND...MODELS HAVE SHIFTED SNOW CHANCES ON FRIDAY AND SATURDAY
TO THE SOUTHEAST THOUGH ARE HAVING TROUBLE COMING TO A CONSENSUS
ON SOME KEY FEATURES. WITH THAT SAID...WILL RETAIN SOME LOWER SNOW
CHANCES MAINLY OVER SOUTHERN AND EASTERN LOCATIONS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1241 PM CST SUN DEC 20 2015

WIDESPREAD MVFR/IFR CONDITIONS IN STRATUS EARLY THIS AFTERNOON
WILL TREND TOWARDS IFR/LIFR THIS EVENING AND OVERNIGHT IN STRATUS
AND FOG. PATCHY FREEZING DRIZZLE MAY BE POSSIBLE.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ001-002-
009-010.

&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...JJS
AVIATION...AYD




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 917 AM CST SUN DEC 20 2015

.UPDATE...
ISSUED AT 915 AM CST SUN DEC 20 2015

QUICK UPDATE TO ISSUE A DENSE FOG ADVISORY FOR NORTHWEST NORTH
DAKOTA THROUGH 19 UTC GIVEN WEBCAM AND SURFACE OBSERVATION TRENDS
THROUGH 15 UTC...AND A NEAR MINIMUM SOLAR ANGLE LIMITING
INSOLATION TO LIFT THE FOG POST SUNRISE.

UPDATE ISSUED AT 845 AM CST SUN DEC 20 2015

OVER THE PAST TWO HOURS THROUGH 1445 UTC...VISIBILITY HAS
CONTINUED TO DECREASE IN FOG ACROSS WESTERN NORTH DAKOTA PER
WEBCAM AND SURFACE OBSERVATIONS...WITH LOCALLY DENSE FOG IN SOME
AREAS. WILL CONTINUE TO MONITOR TRENDS THIS MORNING SHOULD A DENSE
FOG ADVISORY BECOME NECESSARY...AS THE 12-13 UTC HRRR AND 06 UTC
NAM NEST SUGGEST FOG MAY CONTINUE TO EXPAND THROUGH THE MORNING.

UPDATE ISSUED AT 609 AM CST SUN DEC 20 2015

SOME LIGHT SNOW HAS DEVELOPED STRETCHING FROM SOUTHWEST TOWARDS
THE NORTHEAST ACROSS THE STATE WHICH HIGH-RES MODELS ARE NOT
PICKING UP TO WELL. FOR MORNING UPDATES HAVE ADDED POPS TO THE
FORECAST TO ADDRESS THIS. EXPECT THIS SNOW TO DIMINISH BY MID-DAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN DEC 20 2015

MAIN CHALLENGE IN THE SHORT TERM IS CLOUD COVER AND FOG POTENTIAL.

CURRENTLY...AT THE SURFACE...COOL HIGH PRESSURE WAS CENTERED OVER
HUDSON BAY WITH A RIDGE AXIS EXTENDING SOUTHWEST INTO SASKATCHEWAN.
THE BOUNDARY BETWEEN THIS COOL HIGH PRESSURE AND MILDER AIR TO THE
SOUTH WAS A WEAK LOW PRESSURE FRONT ACROSS FAR SOUTHERN
SASKATCHEWAN. AT UPPER LEVELS...A LONGWAVE TROUGH EXTENDED OVER THE
EASTERN ROCKIES AND WAS POISED TO EMERGE INTO THE FRONT RANGE.

THE UPPER LEVEL TROUGH IS FORECAST TO MOVE EAST ACROSS THE DAKOTAS
TODAY AND TONIGHT...BUT THE BASE OF THE TROUGH IS FORECAST TO DEEPEN
NEAR THE 4-CORNERS AREA TODAY AND DEVELOP A STRONGER SHORTWAVE. THIS
WILL WEAKEN THE TROUGHING FARTHER NORTH AND KEEP ANY FORCING FARTHER
TO THE SOUTH OF NORTH DAKOTA TODAY. MEANWHILE THE SURFACE BOUNDARY
IN SOUTHERN SASKATCHEWAN IS FORECAST TO DROP SOUTH ACROSS THE STATE
THIS MORNING...BRINGING WITH IT THE COOLER AND MOIST AIR OF THE
CANADIAN HIGH. SKIES SHOULD REMAIN CLOUDY OVER THE STATE WITH SOME
PATCHY FOG THIS MORNING. THE AXIS OF THE SURFACE HIGH IS FORECAST TO
MOVE SOUTHEAST AND EXTEND FROM MANITOBA ACROSS THE EASTERN DAKOTAS
BY EVENING...WITH THE COOL HIGH PRESSURE RIDGE AXIS REMAINING OVER
THE EASTERN DAKOTAS SUNDAY NIGHT. WHILE CLOUDS MAY DECREASE A BIT IN
THE WEST THIS AFTERNOON...CLOUDS WILL LIKELY INCREASE IN THE WESTERN
PART OF THE STATE TONIGHT AS THE COOL HIGH PRESSURE MOVES EAST AND A
DEVELOPING TROUGH IN THE FRONT RANGE BRINGS SOME WARM ADVECTION AND
VERTICAL MOTION TO WESTERN NORTH DAKOTA.

HIGHS TODAY ARE EXPECTED TO BE IN THE TEENS TO LOWER 20S OVER
NORTHERN AND CENTRAL PARTS OF THE STATE...WITH UPPER 20S AND LOWER
30S IN THE SOUTHWEST. MINIMUM TEMPERATURES SUNDAY NIGHT SHOULD RANGE
FROM 5 TO 10 ABOVE OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA -
CLOSER TO THE COOL RIDGE AXIS - TO THE TEENS IN THE WEST.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN DEC 20 2015

HIGHLIGHT FOR THE EXTENDED PERIOD WILL BE THE OCCASIONAL SNOW
CHANCES AS VARIOUS SHORT WAVES SLIDE THROUGH THE AREA WHILE
TEMPERATURES REMAIN SEASONAL.

ON MONDAY...FAST MOVING SHORT WAVE ZIPS THROUGH THE AREA BRINGING
CHANCES FOR LIGHT SNOW AS IT MOVES THROUGH. ANY ACCUMULATIONS
WILL BE MINIMAL.

FOR TUESDAY...A STRONGER SHORT WAVE PUSHES INTO THE REGION AS A
SURFACE LOW LIFTS THROUGH THE DAKOTAS. THIS WILL BRING INCREASING
SNOW CHANCES OVER NORTHERN AND EASTERN LOCATIONS...WITH THE
GREATEST CHANCES OVER NORTH CENTRAL NORTH DAKOTA WHERE AN INCH OR
TWO OF NEW SNOW WILL BE POSSIBLE. LOW CHANCES FOR SNOW LINGER INTO
WEDNESDAY.

MAINLY QUIET WEATHER EXPECTED ON THURSDAY. GOING INTO THE HOLIDAY
WEEKEND...MODELS HAVE SHIFTED SNOW CHANCES ON FRIDAY AND SATURDAY
TO THE SOUTHEAST THOUGH ARE HAVING TROUBLE COMING TO A CONSENSUS
ON SOME KEY FEATURES. WITH THAT SAID...WILL RETAIN SOME LOWER SNOW
CHANCES MAINLY OVER SOUTHERN AND EASTERN LOCATIONS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 915 AM CST SUN DEC 20 2015

WIDESPREAD MVFR/IFR CONDITIONS IN STRATUS AND FOG THIS MORNING
WILL TREND TOWARDS IFR/LIFR THIS AFTERNOON AND THROUGH THE NIGHT
ACROSS WESTERN AND CENTRAL NORTH DAKOTA.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR NDZ001-002-
009-010.

&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...JJS
AVIATION...AYD




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 849 AM CST SUN DEC 20 2015

.UPDATE...
ISSUED AT 845 AM CST SUN DEC 20 2015

OVER THE PAST TWO HOURS THROUGH 1445 UTC...VISIBILITY HAS
CONTINUED TO DECREASE IN FOG ACROSS WESTERN NORTH DAKOTA PER
WEBCAM AND SURFACE OBSERVATIONS...WITH LOCALLY DENSE FOG IN SOME
AREAS. WILL CONTINUE TO MONITOR TRENDS THIS MORNING SHOULD A DENSE
FOG ADVISORY BECOME NECESSARY...AS THE 12-13 UTC HRRR AND 06 UTC
NAM NEST SUGGEST FOG MAY CONTINUE TO EXPAND THROUGH THE MORNING.

UPDATE ISSUED AT 609 AM CST SUN DEC 20 2015

SOME LIGHT SNOW HAS DEVELOPED STRETCHING FROM SOUTHWEST TOWARDS
THE NORTHEAST ACROSS THE STATE WHICH HIGH-RES MODELS ARE NOT
PICKING UP TO WELL. FOR MORNING UPDATES HAVE ADDED POPS TO THE
FORECAST TO ADDRESS THIS. EXPECT THIS SNOW TO DIMINISH BY MID-DAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN DEC 20 2015

MAIN CHALLENGE IN THE SHORT TERM IS CLOUD COVER AND FOG POTENTIAL.

CURRENTLY...AT THE SURFACE...COOL HIGH PRESSURE WAS CENTERED OVER
HUDSON BAY WITH A RIDGE AXIS EXTENDING SOUTHWEST INTO SASKATCHEWAN.
THE BOUNDARY BETWEEN THIS COOL HIGH PRESSURE AND MILDER AIR TO THE
SOUTH WAS A WEAK LOW PRESSURE FRONT ACROSS FAR SOUTHERN
SASKATCHEWAN. AT UPPER LEVELS...A LONGWAVE TROUGH EXTENDED OVER THE
EASTERN ROCKIES AND WAS POISED TO EMERGE INTO THE FRONT RANGE.

THE UPPER LEVEL TROUGH IS FORECAST TO MOVE EAST ACROSS THE DAKOTAS
TODAY AND TONIGHT...BUT THE BASE OF THE TROUGH IS FORECAST TO DEEPEN
NEAR THE 4-CORNERS AREA TODAY AND DEVELOP A STRONGER SHORTWAVE. THIS
WILL WEAKEN THE TROUGHING FARTHER NORTH AND KEEP ANY FORCING FARTHER
TO THE SOUTH OF NORTH DAKOTA TODAY. MEANWHILE THE SURFACE BOUNDARY
IN SOUTHERN SASKATCHEWAN IS FORECAST TO DROP SOUTH ACROSS THE STATE
THIS MORNING...BRINGING WITH IT THE COOLER AND MOIST AIR OF THE
CANADIAN HIGH. SKIES SHOULD REMAIN CLOUDY OVER THE STATE WITH SOME
PATCHY FOG THIS MORNING. THE AXIS OF THE SURFACE HIGH IS FORECAST TO
MOVE SOUTHEAST AND EXTEND FROM MANITOBA ACROSS THE EASTERN DAKOTAS
BY EVENING...WITH THE COOL HIGH PRESSURE RIDGE AXIS REMAINING OVER
THE EASTERN DAKOTAS SUNDAY NIGHT. WHILE CLOUDS MAY DECREASE A BIT IN
THE WEST THIS AFTERNOON...CLOUDS WILL LIKELY INCREASE IN THE WESTERN
PART OF THE STATE TONIGHT AS THE COOL HIGH PRESSURE MOVES EAST AND A
DEVELOPING TROUGH IN THE FRONT RANGE BRINGS SOME WARM ADVECTION AND
VERTICAL MOTION TO WESTERN NORTH DAKOTA.

HIGHS TODAY ARE EXPECTED TO BE IN THE TEENS TO LOWER 20S OVER
NORTHERN AND CENTRAL PARTS OF THE STATE...WITH UPPER 20S AND LOWER
30S IN THE SOUTHWEST. MINIMUM TEMPERATURES SUNDAY NIGHT SHOULD RANGE
FROM 5 TO 10 ABOVE OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA -
CLOSER TO THE COOL RIDGE AXIS - TO THE TEENS IN THE WEST.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN DEC 20 2015

HIGHLIGHT FOR THE EXTENDED PERIOD WILL BE THE OCCASIONAL SNOW
CHANCES AS VARIOUS SHORT WAVES SLIDE THROUGH THE AREA WHILE
TEMPERATURES REMAIN SEASONAL.

ON MONDAY...FAST MOVING SHORT WAVE ZIPS THROUGH THE AREA BRINGING
CHANCES FOR LIGHT SNOW AS IT MOVES THROUGH. ANY ACCUMULATIONS
WILL BE MINIMAL.

FOR TUESDAY...A STRONGER SHORT WAVE PUSHES INTO THE REGION AS A
SURFACE LOW LIFTS THROUGH THE DAKOTAS. THIS WILL BRING INCREASING
SNOW CHANCES OVER NORTHERN AND EASTERN LOCATIONS...WITH THE
GREATEST CHANCES OVER NORTH CENTRAL NORTH DAKOTA WHERE AN INCH OR
TWO OF NEW SNOW WILL BE POSSIBLE. LOW CHANCES FOR SNOW LINGER INTO
WEDNESDAY.

MAINLY QUIET WEATHER EXPECTED ON THURSDAY. GOING INTO THE HOLIDAY
WEEKEND...MODELS HAVE SHIFTED SNOW CHANCES ON FRIDAY AND SATURDAY
TO THE SOUTHEAST THOUGH ARE HAVING TROUBLE COMING TO A CONSENSUS
ON SOME KEY FEATURES. WITH THAT SAID...WILL RETAIN SOME LOWER SNOW
CHANCES MAINLY OVER SOUTHERN AND EASTERN LOCATIONS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 845 AM CST SUN DEC 20 2015

WIDESPREAD MVFR/IFR CONDITIONS IN STRATUS AND FOG THIS MORNING
WILL TREND TOWARDS IFR/LIFR THIS AFTERNOON AND THROUGH THE NIGHT
ACROSS WESTERN AND CENTRAL NORTH DAKOTA.

&&

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

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...JJS
AVIATION...AYD



AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1233 AM CST SUN DEC 20 2015

.UPDATE...
ISSUED AT 1232 AM CST SUN DEC 20 2015

SURFACE LOW PRESSURE WAS OVER THE WY/SD BORDER WITH ANOTHER WEAKER
LOW OVER FAR SOUTHERN SASKATCHEWAN. AT UPPER LEVELS...A LONGWAVE
TROUGH WAS OVER THE ROCKIES WITH SOUTHWESTERLY FLOW ALOFT OVER THE
WESTERN PLAINS BRINGING SOME WEAK UPPER LEVEL ENERGY IMPULSES OVER
THE FRONT RANGE OVER MONTANA AND WYOMING AND OVER THE DAKOTAS.
CURRENT RADARS INDICATING WEAK RETURNS FROM SOUTH CENTRAL MONTANA
NORTHEASTWARD INTO NORTHWESTERN NORTH DAKOTA. THIS IS LIKELY
INDICATIVE OF SOME WEAK UPPER LEVEL ENERGY AND MID LEVEL CLOUDS. NO
SURFACE OBSERVATIONS INDICATING ANY PRECIPITATION AT OBSERVATION
SITES.

THE LATEST MODELS INDICATE THAT THE UPPER LEVEL ENERGY STREAMS
SHOULD BEGIN TO SHIFT SOUTH WITH TIME OVERNIGHT...WITH THE SURFACE
LOW OVER SOUTHERN SASKATCHEWAN MOVING SOUTHEAST. KEPT THE TRENDS
FROM THE PREVIOUS UPDATE WITH THE SLIGHT CHANCE OF LIGHT SNOW
NORTHWEST NORTH DAKOTA SHIFTING SOUTHWARD TO SOUTHWESTERN NORTH
DAKOTA TOWARDS DAYBREAK. ALSO LOOK FOR AREAS OF FOG AS LATEST HIGH
RESOLUTION MODELS INDICATE VARYING CLOUD LAYERS AND VISIBILITIES AS
THE LOW/FRONT IN SASKATCHEWAN MOVES SOUTHEAST. TEMPERATURES IN THE
SOUTHWEST SHOULD BE FAIRLY STEADY IN THE LOW TO MID 20S...WITH LOWS
ELSEWHERE FROM 5 TO 15 ABOVE.

UPDATE ISSUED AT 935 PM CST SAT DEC 19 2015

LATEST SATELLITE/RADAR AND SURFACE OBSERVATIONS INDICATE MAINLY
MVFR CEILINGS ACROSS FAR NORTHERN NORTH DAKOTA...WITH A PATCH OF
IFR CEILINGS OVER NORTHWEST ND INTO NORTHEAST MT. LATEST SURFACE
ANALYSIS INDICATES OVERALL WEAK SURFACE PATTERN...BUT LOW PRESSURE
OVER SOUTHEAST SASKATCHEWAN...WHICH IS FORECAST TO TRACK SOUTH AND
EAST ACROSS THE FORECAST AREA TONIGHT. HAVE ADJUSTED TEMPERATURES
LOWER AGAIN...BUT CURRENT T/TD SPREADS ARE CLOSE AND INCREASING
WARM ADVECTION/CLOUDS AND POSSIBLY LIGHT SNOW SPREADING WEST TO
EAST SHOULD INHIBIT TEMPERATURES FROM FALLING MUCH FARTHER IN THE
EAST...WITH STEADY AND SOME RISING TEMPERATURES WEST. LATEST HI
RESOLUTION GUIDANCE HAS BACKED OFF ON THE LIGHT PRECIPITATION
DROPPING SOUTH AND EAST ACROSS WESTERN NORTH DAKOTA TONIGHT.
HOWEVER WE DO SEE AN AREA OF HIGHER REFLECTIVITIES WHICH COULD
RESULT IN SOME LIGHT SNOW REACHING THE GROUND...POISED TO MOVE
INTO THE WEST SHORTLY. DID FOLLOW THE TREND OF THE LATEST GUIDANCE
BUT WITH A MIX OF PERSISTENCE WHICH STILL KEEPS SOME SLIGHT CHANCE
POPS DROPPING SOUTH ACROSS MAINLY WESTERN NORTH DAKOTA TONIGHT.

UPDATE ISSUED AT 537 PM CST SAT DEC 19 2015

...QUICK UPDATE FOR EVENING TEMPERATURES...

LATEST SATELLITE AND RADAR IMAGERY SHOWS MOSTLY CLOUDY CONDITIONS
ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH MAINLY MID AND HIGH
LEVEL CLOUDS. SURFACE LOW PRESSURE REMAINS OVER SOUTHERN
SASKATCHEWAN THROUGH EASTERN MONTANA INTO NORTHEAST WYOMING.
ENOUGH BREAKS AND THIN SPOTS IN THE CLOUDS LATE THIS AFTERNOON TO
ALLOW TEMPERATURES TO QUICKLY DROP OFF. UPDATED OVERNIGHT LOWS
STARTING OUT WITH GRIDDED LAMP GUIDANCE WHICH BETTER DEPICTED THE
QUICK DROP EARLY THIS EVENING...THEN TRANSITIONED TO A TIME-
LAGGED VERSION OF A CONSENSUS OF SHORT RANGE MODELS...SIMILAR TO
THE PREVIOUS FORECAST. ALREADY SEEING TEMPERATURES NEARING
OVERNIGHT LOWS OVER CENTRAL ND.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 237 PM CST SAT DEC 19 2015

FOG POTENTIAL AND LIGHT SNOW TONIGHT HIGHLIGHT THE SHORT TERM
FORECAST.

THE 12 THROUGH 19 UTC HRRR ITERATIONS HAVE BEEN VERY CONSISTENT IN
SUGGESTING THE POTENTIAL FOR FOG TONIGHT INTO SUNDAY MORNING
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. FOG IS FIST EXPECTED TO
FORM ACROSS THE JAMES RIVER VALLEY LATE THIS EVENING WITH
INCREASING LOW LEVEL MOISTURE OVER THE SNOWPACK VIA SOUTHEASTERLY
WINDS...AND PLUME WESTWARD TOWARDS THE HIGHWAY 83 CORRIDOR. ACROSS
THE WEST...BEHIND A WEAK COLD FRONT TONIGHT...STRATUS BUILD DOWN
TO FOG IS ALSO SUGGESTED BY THE HRRR. A SIMILAR SCENARIO IS
HINTED AT IN THE 12 AND 18 UTC NAM NEST VISIBILITY FORECASTS. A
BAND OF LIGHT SNOW IS ALSO POSSIBLE WITH THE AFOREMENTIONED COLD
FRONT TONIGHT INTO EARLY SUNDAY MORNING. ANY SNOWFALL AMOUNTS ARE
EXPECTED TO REMAIN AS A DUSTING AT BEST.

FOR SUNDAY...A COOLER DAY IS EXPECTED ACROSS THE SOUTHWEST WHERE
HIGHS IN 40S ARE OCCURRING THIS AFTERNOON WITH WESTERLY WINDS AND
A LACK OF SNOWPACK. ELSEWHERE...THE TEMPERATURE CHANGE BEHIND THE
WEAK COLD FRONT WILL BE GENERALLY UNNOTICEABLE ON SUNDAY COMPARED
TO SATURDAY HIGHS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 237 PM CST SAT DEC 19 2015

RATHER SEASONABLE LATE DECEMBER TEMPERATURES HIGHLIGHT THE
EXTENDED FORECAST...WITH A SOMEWHAT UNCERTAIN PRECIPITATION
FORECAST.

OVERALL...THE 12 UTC GLOBAL DETERMINISTIC AND ENSEMBLE SUITES ARE
IN GOOD AGREEMENT ON THE LARGE SCALE PATTERN OF A BROAD...LOW
AMPLITUDE UPPER LEVEL CONUS TROUGH FOR MUCH OF THE
PERIOD...POSSIBLY TRANSITIONING TO SPLIT FLOW BY NEXT WEEKEND.
THIS WOULD SUGGEST RATHER SEASONABLE TEMPERATURES WITH NO
SIGNIFICANT WARM UPS OR COOL DOWNS. HOWEVER...THE RATHER
FAST...NEAR ZONAL FLOW AT THE BASE OF THE LOW AMPLITUDE TROUGH
DOES INJECT UNCERTAINTY IN THE TIMING OF MULTIPLE WAVES AND
ASSOCIATED PRECIPITATION EVENTS THROUGH THE PERIOD. THE BEST
AGREEMENT IS ON A WEAK WAVE AND POSSIBLE LIGHT SNOW BAND CENTRAL
ON MONDAY. HOWEVER...THEREAFTER THE MODEL SPREAD WIDENS IN
REGARDS TO SEVERAL POSSIBLE LIGHT SNOWFALL EVENTS LEADING UP TO
CHRISTMAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM CST SUN DEC 20 2015

THE LOW CEILINGS HAVE CLEARED KISN BUT EXPECTING MVFR
TO POSSIBLY IFR CEILINGS BUILDING IN AGAIN BETWEEN 09Z-13Z.
ELSEWHERE...MID AND HIGH CLOUD CIGS AT 06Z BUT HIRES MODELS INDICATE
AN AREA OF MVFR-IFR CEILINGS DROPPING SOUTHEAST FROM KMOT TO KBIS
FROM 09-13Z AND POSSIBLY EXPANDING BACK WEST INTO KISN AND KDIK.
THE HIRES MODELS BRING MVFR VSBYS IN FOG AT KISN/KMOT/KDIK. THE MVFR
CIGS ARE EXPECTED TO BECOME VFR BY EARLY TO MID AFTERNOON ON SUNDAY.

&&

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

$$

UPDATE...JV
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...JV




AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 948 PM EST MON DEC 21 2015

.SYNOPSIS...

IT WILL BE UNSETTLED AND UNSEASONABLY MILD WEATHER WILL CONTINUE
THIS WEEK WITH TEMPERATURES ON TRACK TO PEAK NEAR OR BEYOND RECORD
LEVELS ON CHRISTMAS EVE.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...

LITTLE MORE THAN ISOLATED LIGHT SHOWERS OR SPRINKLES AS OF 9 PM.
PRECIP IS SURGING NE AHEAD OF THE NEXT SHORTWAVE IN THE
FLOW...MOVING INTO WEST VIRGINIA NOW...WITH THE HRRR TIMING THE
RAIN INTO MY SWRN ZONES SHORTLY AFTER MIDNIGHT. HAVE RAISED POPS
CLOSER TO SREF VALUES GIVEN THE LARGE SHIELD OF RAIN UPSTREAM.

TEMPS GOT STUCK IN THE LOWER/MID 40S OVER MUCH OF CWA TODAY...BUT
THEY ALSO WON`T FALL OFF MUCH OVERNIGHT AS LOW LEVEL SW FLOW
CONTINUES TO PUSH WARMER AIR INTO THE REGION.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
PACIFIC SHORTWAVE #2 AND ITS WEAK SURFACE LOW QUICKLY LIFTS
NORTHEAST THROUGH THE LOWER GREAT LAKES INTO THE ST. LAWRENCE
VALLEY/NORTHERN NEW ENGLAND BY 00Z WED. A.M. RAIN SHOULD COME TO
AN END FAIRLY ABRUPTLY EARLY TUESDAY AFTERNOON AS RIDGING BUILDS
IN BEHIND THE DEPARTING SYSTEM. THEREFORE TRENDED HIGH PRECIP
PROBS IN THE MORNING STEADILY DOWNWARD WITH A MAINLY DRY PERIOD
/ALBEIT STILL RATHER CLOUDY/ FROM ROUGHLY 18Z TUESDAY TO 12Z
WEDNESDAY. 24HR RAINFALL AMOUNTS ENDING TUESDAY AFTERNOON SHOULD
AVERAGE BETWEEN 0.25 TO 0.50 INCH IN MOST PLACES WHICH IS RIGHT IN
LINE WITH THE GEFS MEAN. THE SREF MEAN QPF IS A LITTLE WETTER
WHICH IS LIKELY DUE TO THE NAM INFLUENCE BEING TOO VIGOROUS WITH
ITS ASCENT AND MOISTURE FIELDS PER WPC MODEL DIAG.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THERE ARE SEVERAL MAJOR FORECAST QUESTIONS THIS WEEK. THE MOST
ANOMALOUS IS THE POSSIBLE RECORD TEMPERATURES. THE LONG AND MID
RANGE MODELS CONTINUE TO BE IN FAIR AGREEMENT WITH THE OVERALL
PATTERN AND BY THURSDAY THE SREF ENSEMBLES HAVE +14C TEMPS AT
850HPA. SO RECORD TEMPERATURES ACROSS CENTRAL PA ARE STILL ON
TRACK FOR CHRISTMAS EVE WITH FCST HIGHS OF 60-70F DEGREES WITH
MILD TEMPERATURES ALL WEEK.

THE NEXT QUESTION IS THE TIMING OF SUCCESSIVE SHORT WAVES MOVING
THROUGH THE UPPER LEVEL PATTERN. AS AN UPPER LEVEL TROUGH
MOVES INTO THE GREAT LAKE REGION...A MID LEVEL TROUGH WILL
MOVE THROUGH THE OHIO VALLEY. THIS SHOULD BRING STRONG WARM AND MOIST
SOUTHWESTERLY FLOW INTO THE REGION LATE WEDNESDAY...EARLY
THURSDAY.  THE LATEST GEFS HAS PWATS OF +3 TO +4 STANDARD
ANOMALIES. SO THAT EVENT SHOULD HAVE THE HEAVIEST
PRECIPITATION. HAVE INCREASED QPF/S UPWARDS...AS WELL AS ADJUSTED
POPS ACCORDINGLY. THAT WARM FRONT WILL BE FOLLOWED BY A WEAKENING
COLD FRONT CHRISTMAS EVE. THE FROPA WILL KNOCK TEMPERATURES BACK
SOME FOR CHRISTMAS DAY BUT IT SHOULD REMAIN ABOVE NORMAL INTO THE
WEEKEND.

THE MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS NOW TRENDING
TOWARD THE IDEA OF A POTENTIAL SIGNIFICANT RAINFALL AXIS SETTING
UP ALONG THE OLD COLD FRONT THAT COULD TRANSITION TO A QUASI-
STATIONARY BOUNDARY. THE GFS/ECMWF DIFFER TO SOME EXTENT ON THE
EVOLUTION OF THE BOUNDARY BUT BOTH SEEM TO FAVOR A RAINFALL AXIS
FROM ROUGHLY DALLAS TX NEWD THROUGH NEW ENGLAND...SATURDAY NIGHT
INTO SUNDAY. CONFIDENCE IN THE PCPN DETAILS DROPS OFF BY THE END
OF THE PERIOD GIVEN THE MODEL SPREAD AND VARIABILITY IN THE
PLACEMENT OF THE PRECIPITATION- FOCUSING BOUNDARY. HOWEVER THE
BOUNDARY SHOULD DIP SOUTHWARD INTO NEXT WEEK AS THE FLOW BECOMES
MORE ZONAL AS THE LOW MOVES INTO THE CENTRAL UNITED STATES.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
SURFACE LOW PRESSURE WILL MOVE FROM THE MIDWESTERN STATES TO THE
EASTERN GREAT LAKES BY TUESDAY AFTERNOON. A PLUME OF DEEP MOISTURE
WITH ITS ORIGIN OVER THE GULF OF MEXICO...WILL BE FUNNELED INTO
PENNSYLVANIA LATER TONIGHT INTO EARLY TUESDAY AFTERNOON...BRINGING
PERIODS OF RAIN AND GENERALLY IFR CIGS AND VSBYS.

FOR EARLY TONIGHT...IFR CONDITIONS /IN THE FORM OF LOW CIGS/ OVER
NWRN PENN WILL SLOWLY SPREAD SOUTH AND EAST LATE TONIGHT REACHING
THE CENTRAL RIDGE AND VALLEY REGION BEFORE DAYBREAK. ONLY A FEW
BRIEF SHOWERS ARE EXPECTED EARLY TONIGHT.

THE SUSQ VALLEY AIRFIELDS WILL STAY VFR UNTIL LATE THIS EVENING
FOLLOWED BY A DROP INTO MVFR CIGS...WITH VFR TO MVFR VSBYS IN
INTERMITTENT VERY LIGHT RAIN/SHOWERS.

STIFF SSW-SWRLY LOW LEVEL JET WILL CONTINUE THE LLWS OVER WESTERN
TERMINALS THROUGH THE OVERNIGHT. MORE NUMEROUS SHOWERS OR EVEN
SOME PERIODS OF STEADIER RAIN WILL ARRIVE FROM THE SW LATER
TONIGHT AND CONTINUE INTO THE EARLY AFTERNOON.

FAIRLY ABRUPT IMPROVEMENT SHOULD OCCUR LATE TUE AFTERNOON AS
RIDGE QUICKLY WORKS IN BEHIND THE DEPARTING SYSTEM.

UNSETTLED WEATHER WILL PERSIST ACROSS CENTRAL PA INTO THURSDAY...
WITH BREEZY CONDITIONS DEVELOPING.


OUTLOOK...
TUE...WIDESPREAD RESTRICTIONS IN RAIN. IMPROVEMENT IN THE
AFTERNOON.

WED...CIG RESTRICTIONS AND ANOTHER ROUND OF RAIN LIKELY. BREEZY.

THU...CIG RESTRICTIONS POSS WEST. IMPROVING CONDITIONS ELSEWHERE.
CONTINUED BREEZY.

CHRISTMAS...NO SIG WX EXPECTED.

SAT...RESTRICTIONS POSS SOUTH.

&&

.CLIMATE...
DECEMBER 2015 CONTINUES TO BE UNSEASONABLY MILD. ANOTHER ROUND OF
WELL ABOVE AVERAGE TEMPERATURES THIS WEEK WILL BRING POTENTIALLY
RECORD SETTING TEMPERATURES FOR WEDNESDAY AND THURSDAY /CHRISTMAS
EVE/. HERE ARE THE CURRENT RECORDS FOR WEDNESDAY THE 23RD AND
THURSDAY THE 24TH...

RECORD HIGH TEMPERATURES...
SITEWED RECORDTHU RECORDNORMAL
HARRISBURG65F (1990)62F (1990)39F
WILLIAMSPORT63F (1990)56F (1931)36F
ALTOONA62F (1957)62F (1965)36F
BRADFORD56F (1990)55F (1965)31F
STATE COLLEGE*65F (1933)63F (1933)36F
*STATE COLLEGE RECORD IS FROM 7AM TO 7AM COOP SITE...
I.E. WEDNESDAY/S RECORD IS ACTUALLY 7AM WED - 7AM THU

RECORD HIGH LOW TEMPERATURES...
SITETHU RECORDFRI RECORDNORMAL
HARRISBURG49F (1931)45F (1891)25F
WILLIAMSPORT45F (2014)43F (1895)22F
ALTOONA41F (1972)42F (1987)21F
BRADFORD44F (1965)42F (1982)16F
STATE COLLEGE*45F (1931)46F (1893)22F
*STATE COLLEGE RECORD IS FROM 7AM TO 7AM COOP SITE...
I.E. THURSDAY/S RECORD IS ACTUALLY 7AM WED - 7AM THU

WITH THE CONTINUED VERY MILD TEMPERATURES...DECEMBER 2015 IS ON
TRACK TO BE THE WARMEST DECEMBER ON RECORD AT ALL SITES.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...RXR
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/RXR
CLIMATE...



AREA FORECAST DISCUSSION

NWS MEMPHIS TN

 906 PM CST MON DEC 21 2015

.UPDATE...

A COLD FRONT IS ON THE DOOR STEPS OF NORTHEAST ARKANSAS AT THIS
TIME. MOST OF THE HEAVIER SHOWER ACTIVITY HAS PUSHED EAST OF THE
CWA. ALTHOUGH A NEW BAND OF SHOWERS HAS DEVELOPED OVER THE LAST
FEW HOURS JUST AHEAD OF THE FRONT. THE HRRR SHOWS THIS BAND
EXPANDING A TAD AS IT PUSHES EASTWARD ACROSS THE MIDSOUTH. WILL
KEEP POPS AS IS FOR THE REMAINDER OF THE NIGHT.

IN ADDITION...SOME CLEARING MAY OCCUR ACROSS NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL BEHIND THE FRONT. A LITTLE WORRIED DENSE
FOG MAY DEVELOP AS WINDS WILL REMAIN LIGHT. DENSE FOG IS ALREADY
BEING REPORTED NEAR CLINTON ARKANSAS. FOR NOW WILL ADD AREAS OF
FOG FOR AREAS ALONG AND WEST OF THE MISSISSIPPI RIVER. UPDATE WILL
BE OUT SHORTLY.

KRM

&&

.DISCUSSION... /ISSUED 348 PM CST MON DEC 21 2015/

WE REMAIN IN A VERY ACTIVE PATTERN. EXPECT RAIN ACROSS AT LEAST A
PORTION OF THE MIDSOUTH EVERY DAY THROUGH THE END OF THE WEEKEND.
ABNORMALLY WARM CONDITIONS WILL ALSO CONTINUE. THIS FORECAST
UPDATE WILL FOCUS PRIMARILY ON THE THREAT FOR SEVERE THUNDERSTORMS
LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO CONTINUE BEFORE AND AFTER THEN.

CURRENTLY RAIN IS MOSTLY CONFINED TO NORTH MISSISSIPPI AND A
SMALL AREA OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. EMBEDDED
THUNDERSTORMS HAVE BEEN NOTED...ALTHOUGH NOTHING TO BE CONCERNED
ABOUT. TEMPERATURES ARE IN THE MIDDLE 50S TO LOW 60. A MODERATE
SOUTH WIND IS PUMPING GULF MOISTURE ACROSS THE AREA...SETTING THE
STAGE FOR A POTENTIAL ROUND OF SEVERE WEATHER MIDWEEK.

TOMORROW SHOULD BE WARMER...IN THE LOW 60S TO LOW 70S ACROSS MOST
OF THE REGION...RAIN SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE...MAINLY IN NORTH MISSISSIPPI.

TEMPERATURES WEDNESDAY WILL BE 22-28 DEGREES ABOVE NORMAL...MAINLY
IN THE MIDDLE 70S. DEW POINTS WILL BE AS HIGH AS THE MIDDLE
60S...CREATING AN AIRMASS THAT FEELS MORE LINE SPRING THEN LATE
DECEMBER.

SYNOPTICALLY...OVER THE NEXT 48 HOURS OR SO A VERY BROAD TROUGH
WILL DEEPEN OVER THE WESTERN US...AND SHIFT INTO THE PLAINS. LATE
TUESDAY NIGHT INTO EARLY WEDNESDAY ITS AXIS SHOULD BE OVER
CENTRAL OKLAHOMA...WITH A SLIGHTLY NEGATIVELY TILTED SHORTWAVE
APPROACHING THE MISSISSIPPI RIVER VALLEY. THE STORM PREDICTION
HAS INCLUDED A LARGE PORTION OF THE MIDSOUTH...MAINLY ALONG AND
SOUTH OF THE INTERSTATE 40 CORRIDOR IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. WARM TEMPERATURES AND DEW POINTS IN THE 60S WILL
CREATE VERY UNSTABLE ATMOSPHERIC CONDITIONS...ESPECIALLY FOR
DECEMBER. THE NAM GENERATES CAPE VALUES IN EXCESS OF 1000J/KG AS
FAR NORTH AS MEMPHIS...WITH THE GFS NOT MUCH LOWER IN VALUES...BUT
NOT AS FAR NORTH SPATIALLY. I TYPICALLY DO NOT PUT MUCH FAITH IN
CONVECTIVE PARAMETERS MORE THAN 36 HOURS IN THE FUTURE...BUT
VALUES THAT HIGH ARE HARD TO IGNORE. SHEAR PROFILES ARE ALSO
FAIRLY IMPRESSIVE...AND NOT OVERLY INTENSE WHERE MANY TIMES THEY
ARE A DETRIMENT TO SUSTAINED UPDRAFTS. STRONGLY CURVED HODOGRAPHS
FEATURE 0-3KT HELICITY UP TO 300 M^2/S^2 IN NORTH MISSISSIPPI.
1000-500MB LAPSE RATES ARE BETWEEN 5.8C/KM AND 6.2 C/KM. ORGANIZED
SEVERE STORM ARE POSSIBLE...INCLUDING SUPERCELLS. LARGE
HAIL...LOCALLY DAMAGING WIND GUSTS AND TORNADOES ALL APPEAR
POSSIBLE. HOLIDAY TRAVELERS SHOULD PAY PARTICULARLY CLOSE
ATTENTION TO THIS FORECAST.

THE SEVERE THREAT SHOULD DIMINISH OVERNIGHT AS THE SHORTWAVE
TROUGH SHIFTS ACROSS THE MISSISSIPPI RIVER VALLEY. HOWEVER...THE
LARGER SCALE TROUGH WILL REMAIN ANCHORED OVER THE CENTRAL PLAINS.
AS A RESULT WE MAY SEE A BREAK IN WIDESPREAD RAIN AND
THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY. UNFORTUNATELY
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO RETURN CHRISTMAS EVE
NIGHT. HOPEFULLY SANTA CAN GET ALL THE GIFTS DELIVERED ACROSS THE
MIDSOUTH BEFORE THE RAIN BEGINS.

LATE IN THE WORK WEEK...A DEEPENING TROUGH OVER THE SOUTHWEST WILL
RESULT IN STRONG SOUTHWEST FLOW ACROSS THE MIDSOUTH. THIS
TYPICALLY MEANS WET CONDITIONS ACROSS OUR AREA. THIS TIME DOESN`T
LOOK LIKE AN EXCEPTION. WILL CARRY HIGH CHANCE TO EVEN LIKELY POPS
FRIDAY THROUGH THE WEEKEND. TEMPERATURES WILL REMAIN SEASONABLY
WARM.

30

&&

.AVIATION...

00Z TAF CYCLE

IFR CONDS ACROSS THE AREA ATTM. A WEAKENING COLD FRONT IS
APPROACHING THE REGION. THE HEAVIEST RAIN WILL MOVE ACROSS KTUP
THIS EVENING WITH A FEW CLAPS OF THUNDER. PATCHY DRIZZLE/LIGHT
RAIN IS POSSIBLE ACROSS THE KMEM/KMKL CORRIDOR. EXPECT CONDS TO
DETERIORATE FURTHER TO LIFR AFTER MIDNIGHT AREAWIDE IN LOW
CLOUDS...PATCHY DRIZZLE AND FOG. FOG MAY BE MORE DENSE ACROSS KJBR
SINCE THEY STAND THE BEST CHANCE OF LOOSING THE CLOUD DECK LATER
TONIGHT. CONDS WILL GRADUALLY IMPROVE TUESDAY MORNING THOUGH KEPT AN
MVFR DECK GOING THROUGH THE DAY FOR NOW.

SOUTHERLY WINDS AROUND 8 KTS WILL GRADUALLY VEER TO THE WEST/NW
AND BECOME LIGHT/VRBL AT KJBR/KMEM/KMKL AS THE FRONT MOVES INTO
THE AREAS AND WASHES OUT. LIGHT SOUTHERLY WINDS WILL REDEVELOP
TUESDAY AFTN. FRONT NEVER REALLY MAKES IT TO KTUP AND WINDS REMAIN
S/SSW THERE.

SJM

&&



&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$




AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 1207 PM CST SUN DEC 20 2015

.AVIATION...
THE MAIN CONCERN THIS TAF CYCLE WILL BE THE WINDS...WHICH WILL
CONTINUE ON THE GUSTY SIDE /SUSTAINED AROUND 20-25 KNOTS WITH
GUSTS TO 30-35 KNOTS/ THROUGH EARLY EVENING. THE SOUTH TO
SOUTHWESTERLY WINDS WILL GRADUALLY DIMINISH TOWARD SUNSET...BUT
MAY BRIEFLY INCREASE AS THEY VEER WESTERLY BEHIND A PACIFIC FRONT
THIS EVENING. GUSTY WINDS WILL THEN REDEVELOP /THOUGH THIS TIME
OUT OF THE WEST/ AT KLBB AND KPVW BY LATE MONDAY MORNING...THOUGH
KCDS SHOULD SEE LIGHTER WINDS PERSIST. OTHERWISE...THE PLETHORA OF
HIGH CLOUDS CURRENTLY ABOVE THE TERMINALS WILL THIN AND SHIFT EAST
WITH TIME...WITH VFR CONDITIONS PREVAILING THROUGH MONDAY.

&&

.UPDATE...
GUSTY SOUTHERLY TO SOUTHWESTERLY WINDS WILL CONTINUE THROUGH THE
AFTERNOON HOURS. THESE WINDS SHOULD GENERALLY BE SUSTAINED IN THE
20-30 MPH RANGE...THOUGH COULD BRIEFLY EDGE SLIGHTLY ABOVE THIS.
WE WILL CONTINUE TO MONITOR OBSERVATIONS AND TRENDS AND IF WINDS
DO EDGE UP A LITTLE HIGHER THAN CURRENTLY EXPECTED/FORECAST A
SHORT DURATION WIND ADVISORY COULD BE NEEDED. OTHERWISE...RECENT
HRRR AND RAP OUTPUT SUGGEST A POCKET OF DRY AIR WILL DEVELOP IN
THE LEE OF THE SACRAMENTOS AND ADVECT INTO THE WESTERN ZONES BY
MID TO LATE AFTERNOON. IF THIS OCCURS THE WESTERN SOUTH PLAINS
COULD EXPERIENCE A FEW HOURS OF ELEVATED TO CRITICAL FIRE WEATHER.
WE WILL WATCH THIS CLOSELY AND IF NEEDED A FIRE DANGER STATEMENT
WILL BE ISSUED. OTHERWISE...THE ONGOING FORECAST REMAINS ON TRACK
WITH A MILD/WARM BUT WINDY WINTER DAY UNFOLDING.

&&

.PREV DISCUSSION... /ISSUED 402 AM CST SUN DEC 20 2015/

SHORT TERM...
UPPER SHORTWAVE TROUGH MOVING ACROSS THE SOUTHERN TIP OF NEVADA WILL
TRANSLATE EAST TODAY AS A SURFACE LOW KICKS OUT OF COLORADO INTO
THE CENTRAL PLAINS. THIS IN AND OF ITSELF WOULD SPELL LOW END
WINDY CONDITIONS WITH H85 WIND SPEEDS RANGING FROM 25-40
KNOTS...BUT HIGH CLOUDS FOLLOWED BY A ROUND OF MID CLOUDS AND
PERHAPS ANOTHER ROUND OF CIRRUS WILL KEEP SPEEDS DOWN A TOUCH AS
MIXING WILL BE INHIBITED AT LEAST THIS MORNING AND POSSIBLY INTO
EARLY THIS AFTERNOON. SOUTHWEST WINDS WILL STILL INCREASE TO 15-25
MPH BY MID AFTERNOON...HELPING TO WARM TEMPERATURES INTO THE MID-
UPPER 60S AS CLOUDS DEPART FROM WEST TO EAST. ELEVATED FIRE
WEATHER CONDITIONS WILL LIKELY MATERIALIZE AT TIMES THIS AFTERNOON
MAINLY ON THE CAPROCK...BUT ENOUGH MOISTURE SHOULD REMAIN IN PLACE
TO PREVENT WIDESPREAD CRITICAL CONDITIONS AND NEED FOR A FIRE
DANGER STATEMENT. LOW STRATUS HAS MANAGED TO REMAIN EAST OF THE
ROLLING PLAINS SO FAR THIS MORNING...BUT COULD VERY WELL SEE SOME
OF THIS STREAM INTO THE EASTERN ROLLING PLAINS. DESPITE THE
PRESENCE OF ENHANCED MOISTURE AHEAD OF THE APPROACHING UPPER
DISTURBANCE...A STUBBORN DRY LAYER RESIDING NEAR THE H85-H70 LAYER
ALONG WITH THE CORE OF THE MID LEVEL TROUGH PASSING ACROSS THE
NORTHERN TEXAS PANHANDLE INTO THE CENTRAL PLAINS SHOULD KEEP
CONDITIONS DRY ACROSS THE SOUTH PLAINS REGION. PACIFIC COLD FRONT
LOOKS TO PUSH THROUGH THIS EVENING FILTERING IN DRIER/COOLER
AIR...WITH WEST WINDS GRADUALLY DIMINISHING TO 5-10 MPH OVERNIGHT
AS TEMPERATURES DROP INTO THE LOW-MID 30S ACROSS THE SOUTH
PLAINS/FAR SOUTHWEST PANHANDLE AND MID 30S-LOW 40S IN THE ROLLING
PLAINS AND FAR SOUTHEAST PANHANDLE.

LONG TERM...
MONDAY MORNING SHOULD SEE A MINOR EMBEDDED TROUGH JUST TO THE WEST
OF THE CWFA. THIS FEATURE SHOULD LARGELY COME AND GO BY LUNCHTIME
LEAVING ZONAL FLOW IN PLACE UNTIL TUESDAY MORNING WHERE WINDS WILL
BACK SOUTHWESTERLY AS A BROAD TROUGH AXIS DIGS JUST A BIT AND PASSES
WEDNESDAY MORNING.  THE NEXT SIGNIFICANT SYSTEM DIGS INTO THE
SOUTHWEST INTO EARLY FRIDAY.  MODELS ARE NOT NEARLY AS CONSISTENT
WITH THE EVOLUTION OF THE SYSTEM AS THEY WERE LAST NIGHT AND WILL
MAINTAIN SOME RESEMBLANCE OF STATUS QUO UNTIL THE CALCULATIONS
CAN START CONVERGING ON SOMETHING.

WINDS HAVE TRENDED HIGHER ON MONDAY THANKS TO A NEW WAVE THAT IS
STARTING TO RESOLVE ITSELF IN THE MEAN FLOW.  THE BREEZY...THOUGH
NOT WINDY...CONDITIONS WILL PERSIST INTO TUESDAY THOUGH WEDNESDAY
HAS TRENDED TO BE THE BREEZIEST OF THE BATCH WITH NEAR ADVISORY
SPEEDS POSSIBLE UP IN THE NORTHWEST BEHIND A PACIFIC FRONT. A
FRONTAL BOUNDARY EASES SOUTH INTO THE AREA EARLY THURSDAY BUT
FAILS TO MAKE TOO MUCH SOUTHWARD PROGRESS. IN FACT THERE IS
UNCERTAINTY THAT IT WILL MAKE IT SOUTH THROUGH OUR ENTER AREA
THOUGH COOLER TEMPS ARE ON TAP. CHRISTMAS DAY LOOKS TEMPERATE
THOUGH MUCH COLDER AIR IS ANTICIPATED OVERNIGHT INTO BOXING DAY.
SOME PRECIPITATION REMAINS IN THE GFS SOLUTION WHICH IS MOST
SIMILAR TO LAST NIGHT/S RUNS.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

23/07/23




AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 331 AM CST SUN DEC 20 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST SUN DEC 20 2015

MAIN FORECAST CONCERNS ARE ON DRIZZLE/FREEZING DRIZZLE POTENTIAL
LATE THIS AFTERNOON INTO TONIGHT.

A TIGHT PRESSURE GRADIENT WAS IN PLACE ACROSS THE REGION THIS
MORNING  WITH INCREASING SOUTHERLY FLOW BRINGING WARMER
TEMPERATURES INTO THE AREA...AT LEAST WARMER THAN WHAT WE SAW
SATURDAY MORNING. EARLY MORNING READINGS RANGE FROM THE LOWER 20S
TO UPPER 30S. A WEAK COLD FRONT WAS ADVANCING EASTWARD ACROSS THE
DAKOTAS. THIS FRONT WILL MOVE INTO THE UPPER MISSISSIPPI RIVER
VALLEY TODAY AND INTERACT WITH A TROUGH LIFTING NORTHEAST OUT OF
THE CENTRAL PLAINS...GENERATING SOME DRIZZLE ACROSS PARTS OF THE
FORECAST AREA...MAINLY TONIGHT. LATEST FORECAST GUIDANCES HAS
REALLY SLOWED THE ARRIVAL OF DRIZZLE AND THIS HAS BEEN INDICATED
IN THE LAST THREE MODEL RUNS. ALSO...MODELS ARE TRENDING DRIER
ACROSS PORTIONS OF SOUTHEAST MINNESOTA INTO WEST CENTRAL
WISCONSIN. WITH THE LATER ONSET TO THE DRIZZLE...FREEZING DRIZZLE
POTENTIAL WILL BE LIMITED. HOWEVER...WITH THE RECENT SUBFREEZING
TEMPERATURES WOULD EXPECT TO SEE PATCHY FREEZING DRIZZLE WHERE
ROAD SURFACES REMAIN BELOW FREEZING...ESPECIALLY AT THE ONSET OF
THE DRIZZLE. PORTIONS OF NORTHEAST IOWA AND SOUTHER WISCONSIN WILL
HAVE THE BEST CHANCES OF SEEING DRIZZLE AND POSSIBLE LIGHT RAIN
LATE TONIGHT INTO MONDAY MORNING. COLDER AIR STARTS TO WRAP INTO
THE SYSTEM VERY LATE TONIGHT INTO MONDAY MORNING SO WE WILL THEN
MOST LIKELY SEE A SWITCH OVER TO LIGHT SNOW OR FREEZING DRIZZLE
BEFORE THE PRECIPITATION ENDS. ANY SNOWFALL OR ICE ACCUMULATIONS
WILL BE VERY LIGHT. SATURATION TRIES TO LINGER ACROSS THE AREA
INTO MONDAY NIGHT AND WE COULD SEE SOME LIGHT SNOW OR FREEZING
DRIZZLE LINGER...BUT CONFIDENCE IS LOW ON THIS OCCURRING.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 331 AM CST SUN DEC 20 2015

WE WILL SEE A BREAK IN PRECIPITATION CHANCES LATE MONDAY NIGHT
THROUGH TUESDAY AS WEAK HIGH PRESSURE SLIDES THROUGH. A TROUGH
THEN DEVELOPS ACROSS THE CENTRAL CONUS ON TUESDAY INTO TUESDAY
NIGHT. THE A SHORTWAVE EJECTS OUT OF THIS TROUGH AND INTO THE
FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY BRINGING THE
NEXT CHANCE OF PRECIPITATION TO THE REGION. WITH INCREASING WARM
SOUTHERLY FLOW...MOST OF THE PRECIPITATION WILL BE IN THE FORM OF
DRIZZLE TUESDAY NIGHT WITH RAIN EXPECTED ON WEDNESDAY. WE COULD
THEN SEE A SWITCH OVER TO SNOW WEDNESDAY NIGHT AS COLDER AIR WRAPS
INTO THE BACK SIDE OF THE SYSTEM. A PERSISTENT TROUGH THEN CARVES
OUT ACROSS THE WESTERN HALF OF THE CONUS PLACING THE UPPER
MISSISSIPPI RIVER VALLEY IN SOUTH/SOUTHWEST FLOW ALOFT. SEVERAL
PIECES OF SHORTWAVE ENERGY WILL EJECT OUT OF THIS TROUGH FROM
WEDNESDAY NIGHT THROUGH SATURDAY. FORECAST MODELS ARE STRUGGLING
TIMING THESE WAVES. A MODELS CONSENSUS BLEND WAS LEANED TOWARDS
FOR PRECIPITATION CHANCES DURING THIS TIMEFRAME. AFTER THE FIRST
ROUND OF RAIN AND SNOW CHANCES FINALLY EXITS ON THURSDAY...THE
NEXT LOOKS TO ARRIVE FRIDAY INTO FRIDAY NIGHT. BEYOND FRIDAY NIGHT
THE MODELS REALLY START TO DIVERGE SO FORECAST CONFIDENCE IF VERY
LOW GOING INTO NEXT WEEKEND. IT APPEARS TEMPERATURES WILL STAY ON
THE WARM SIDE FOR THIS TIME OF YEAR WITH HIGHS IN THE 30S TO LOW
40S WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CST SAT DEC 19 2015

WILL START BOTH SITES WITH WIND SHEAR AND HAVE IT THROUGH THE
OVERNIGHT HOURS. THE 20.00Z NAM AND 20.03Z RAP CAME IN WITH
STRONGER WINDS ABOVE THE SURFACE AND THE 20.00Z SOUNDING FROM KOAX
DID SHOW 45 KNOTS AROUND 2500 FEET SO THE WINDS IN THE MODELS MAY
BE PRETTY REASONABLE. THE NAM ALSO CAME IN WITH A SLOWER TREND IN
BRINGING IN THE LOW LEVEL MOISTURE FOR THE MVFR/IFR
CEILINGS...WHICH THE RAP AGREED WITH...SO PUSHED THESE BACK TO
ABOUT THE MIDDLE OF THE AFTERNOON. THE FORECAST SOUNDINGS THEN
SHOW THE LOW LEVEL SATURATION DEPTH INCREASING TO AROUND 5000 FEET
WITH SOME LIFT THROUGH THIS FROM THE ONGOING ISENTROPIC UP GLIDE
FOR THE POSSIBILITY OF DRIZZLE. ADDED IT TO BOTH TAF SITES FOR
SUNDAY EVENING...BUT THE NAM AND THE HI-RES MESO MODELS SUGGEST
THERE IS THE POSSIBILITY THAT IT COULD MISS KRST.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04




AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1141 PM CST SAT DEC 19 2015

.SHORT TERM...(TONIGHT THRU SUNDAY NIGHT)
ISSUED AT 225 PM CST SAT DEC 19 2015

MAIN FORECAST CONCERNS THIS PERIOD...DZ/FZDZ/FOG CHANCES SUN
AFTERNOON/ NIGHT...TEMPERATURES THRU THE PERIOD.

DATA ANALYSIS AT 18Z HAD THE SFC RIDGE AXIS FROM EASTERN MAN TO
CENTRAL IL. SUNNY/MOSTLY SUNNY SKIES ACROSS MOST OF THE UPPER
MIDWEST UNDER THE SFC RIDGE AXIS AND JUST EAST OF THE MID LEVEL
RIDGE AXIS. HOWEVER SOME CIRRUS WERE SLIDING THRU THE UPPER RIDGE
AXIS...MAINLY OVER THE NORTH HALF OF THE REGION. WINDS WERE TURNING
SOUTH ACROSS MN/IA...BUT EVEN WITH THE SUNNY/MOSTLY SUNNY SKIES MID
DAY TEMPS AROUND MUCH OF THE REGION WERE NEAR TO A FEW DEGREES BELOW
NORMAL.

19.12Z MODEL RUNS INITIALIZED WELL AND OFFER A TIGHT CONSENSUS OF
SOLUTIONS AS MID LEVEL RIDGING MOVES ACROSS THE UPPER MIDWEST
TONIGHT. TREND FAVORS SLOWER OF EARLIER RUNS ON THE TROUGH/SHORTWAVE
ENERGY MOVING INTO THE CENTRAL/SOUTHERN ROCKIES TONIGHT. THIS SLOWER
TREND...FAVORING THE EARLIER ECMWF RUNS...CONTINUES SUNDAY/SUN NIGHT
AS THIS TROUGH/ENERGY AND A NORTHERN STREAM WAVE MOVE INTO THE
CENTRAL/NORTHERN PLAINS SUN THEN INTO THE REGION SUN NIGHT. EVEN
WITH SOME TIMING SHIFT AMONG THE MODELS...THE RATHER TIGHT CONSENSUS
KEEPS SHORT-TERM FORECAST CONFIDENCE GOOD THIS CYCLE.

FOR THE SHORT TERM...LOW LEVEL WARM ADVECTION STRENGTHENS OVER THE
REGION TONIGHT AHEAD OF THE SFC-850MB LOW/TROUGH MOVING ACROSS THE
DAKOTAS. 925MB/850MB TEMPS CLIMB TO NEAR/ABOVE 0C ACROSS THE AREA BY
12Z. LOWS STILL EXPECTED TO BE THIS EVENING. THIS AS SOUTH/SOUTHEAST
WINDS FOR BOUNDARY LAYER MIXING INCREASE...HIGH CLOUDS THICKEN OVER
THE AREA LATER TONIGHT AND THE WARM ADVECTION PRODUCE STEADY/SLOWLY
RISING TEMPS AFTER MIDNIGHT. LOWER LEVEL MOISTURE INCREASE...SFC TO
ABOUT 800MB...STILL ON TRACK TO ARRIVE VERY LATE TONIGHT AND MORESO
SUN MORNING. INITIAL MOISTURE LATE TONIGHT/SUN MORNING GENERALLY
BELOW 900MB...ONLY ABOUT 1KM DEEP. THIS AND THE SLOWING OF THE MID
LEVEL TROUGH/SHORTWAVE...LEFT FORECAST GRIDS DRY THRU 18Z SUN.
DEPTH OF MOISTURE INCREASE TO 1.5 TO 2KM SUN AFTERNOON AS
925-850MB WARM ADVECTION AHEAD OF THE LOW LEVEL TROUGH AXIS
REMAINS OVER THE AREA. TOP OF THE MOISTURE COLUMN ONLY 0C TO
-4C...TOO WARM FOR ICE IN THE CLOUDS. DEPTH OF THE MOISTURE AND AN
INVERSION ABOVE IT...PRECIPITATION TYPE SUN AFTERNOON THRU SUN
EVENING CONTINUES TO TREND AS -DZ. BOUNDARY LAYER TEMPS BY SUN
AFTERNOON AND FOR SUN EVENING LOOKING TO MOSTLY BE IN THE MID 30S
TO AROUND 40. HOWEVER RECENT COLD TEMPS HAVE PRODUCED A FEW INCHES
OF GROUND FROST AND ROAD SFC TEMPS THAT ARE BELOW FREEZING. THESE
SURFACES WILL NOT WARM UP/THAW AS FAST AS THE BOUNDARY LAYER TEMPS
WARM ABOVE 32F. THIS LEAVES THE POTENTIAL FOR SOME -FZDZ ON
UNTREATED/SHADED ROAD SURFACES/COLD SIDEWALKS UNTIL THEY WARM
ABOVE 32F. CONTINUED A MENTION OF -FZDZ IN THE GRIDS SUN
AFTERNOON/EVENING MAINLY OVER THE NORTH HALF OF THE FORECAST AREA
WHERE BOUNDARY LAYER TEMPS WILL BE COOLER AND THE COLD GROUND
SLOWER TO WARM UP. WITH THE INCREASING BOUNDARY LAYER MOISTURE
OVER THE COLD GROUND...CONTINUED THE PATCHY FOG MENTION LATE SUN
AFTERNOON AND MUCH OF SUN NIGHT. SIGNAL IS STILL THERE FOR SOME
DEEPER MOISTURE ASSOCIATED WITH THE 700MB TROUGH TO MOVE IN AFTER
MIDNIGHT SUN NIGHT. ENOUGH SO FOR CLOUD TOP TEMPS IN THE -10C TO
-15C RANGE FOR A PERIOD OF ICE IN THE CLOUDS. INCLUDED -SN IN THE
PRECIPITATION MIX BETWEEN ROUGHLY 09Z-15Z MON. BY THIS TIME
THOUGH...FORCING/LIFT IS EXITING AND ANY -SN AMOUNTS WOULD BE
MINIMAL. USED A BLEND OF THE GUIDANCE LOWS TONIGHT/SUN NIGHT. WITH
THICKENING LOW CLOUDS SUN... LEANED TOWARD COOLER OF THE GUIDANCE
HIGHS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 225 PM CST SAT DEC 19 2015

FOR MONDAY THRU TUESDAY NIGHT...

MAIN FORECAST CONCERNS THIS PERIOD...LINGERING WINTRY MIX MON
MORNING... -RA/-SN CHANCES TUE NIGHT...ABOVE NORMAL TEMPERATURES.

GOOD CONSISTENCY AMONG 19.12Z MODELS FOR THE MID LEVEL TROUGH AXIS
TO MOVE QUICKLY EAST OF THE AREA MON MORNING...WITH WEAK SHORTWAVE
RIDGING FOR THE MON AFTERNOON. TIGHTER SIGNAL FOR ANOTHER SHORTWAVE
TO MOVE ACROSS THE MON NIGHT...THEN SOUTHWEST FLOW TO DEVELOP OVER
THE REGION TUE/TUE NIGHT AHEAD OF THE ENERGY COMING THRU THE
NORTHERN ROCKIES AND CARVING OUT A MODEST TROUGH OVER THE CENTRAL/
NORTHERN PLAINS BY 12Z WED. WITH DECENT MODEL AGREEMENT ON THE
DETAILS...FORECAST CONFIDENCE FOR MON THRU TUE NIGHT IS GENERALLY
GOOD THIS CYCLE.

MIXED PRECIPITATION CHANCES COMING OUT OF SUN NIGHT LINGER OVER
THE EAST HALF OF THE FORECAST AREA MON MORNING...AND MAINLY IN THE
12-15Z PERIOD. SOME DEEPER LAYERED SUBSIDENCE TO MOVE ACROSS THE
AREA WITH THE SFC- MID LEVEL RIDGE AXIS. HOWEVER...PLENTY OF LOWER
LEVEL MOISTURE LOOKS TO REMAIN OVER THE AREA MON/MON
NIGHT...TRAPPED UNDER THE STRENGTHENING SUBSIDENCE INVERSION. DID
ADD A PERIOD OF PARTLY SUNNY SKIES MON AFTERNOON...MAINLY TO BLEND
WITH NEIGHBORING GRIDS. HOWEVER IT LOOKS LIKE WE MAY NOT SEE MUCH
IN THE WAY OF SUNSHINE AGAIN UNTIL PERHAPS TUE AFTERNOON IN THE
INCREASING SOUTH/SOUTHWEST FLOW TO ADVECT THE TRAPPED MOISTURE
NORTH/EAST OF THE AREA. SHORTWAVE COMING ACROSS MON NIGHT PROVIDES
SOME MID LEVEL ALONG WITH A RETURN OF SOME 925-850MB WARM
ADVECTION. THIS WHILE MODEL SOUNDINGS/X-SECTIONS SHOW MINIMAL
MOISTURE/SATURATION IN THE 900- 500MB LAYER ABOVE THE TRAPPED SFC-
900MB MOISTURE. LEFT GRIDS DRY MON NIGHT AS THE WAVE WOULD PASS.
STRONGER LOW LEVEL WARM ADVECTION RETURNS TUE...WITH 925-850MB
TEMPS BACK ABOVE 0C OVER THE FORECAST AREA BY 00Z WED. APPEARS IF
LOWER CLOUDS ARE IN FACT ADVECTED OUT TUE...MID/HIGH
MOISTURE/CLOUDS AHEAD OF THE NEXT TROUGH INTO THE PLAINS WOULD
KEEP SKIES MOSTLY CLOUDY/CLOUDY. IF WE DO IN FACT GET A PERIOD OF
SUNSHINE TUE...HIGHS IN THE FORECAST GRIDS FOR TUE MAY BE A FEW
DEGREES TOO COOL. DEEP SATURATION FOR A PRECIPITATION CHANCE TUE
NIGHT LOOKING TO BE A PROBLEM...MUCH LIKE SUN AFTERNOON/NIGHT IS.
ANY SMALL TUE NIGHT PRECIPITATION CHANCE MAY BE MORE -DZ. LEFT
THIS AS -RA/-SN FOR NOW BUT DID TREND IT STRONGLY TOWARD MAINLY
-RA WITH THE 925- 850MB TEMPS NEAR/ABOVE 0C TUE NIGHT. USED A
BLEND OF THE GUIDANCE HIGHS/LOWS FOR MON THRU TUE. WITH SNOW-FREE
GROUND...THICKENING CLOUDS AND SOUTH-SOUTHEAST WINDS FOR BOUNDARY
LAYER MIXING...FAVORED WARMER OF GUIDANCE LOWS TUE NIGHT.

FOR WEDNESDAY THRU SATURDAY...DAYS 4 TO 7...

MAIN FORECAST CONCERNS THIS PERIOD...SMALL RAIN/SNOW CHANCES MOST
OF THE PERIOD...ABOVE NORMAL TEMPERATURES.

MEDIUM RANGE MODEL RUNS OF 19.00Z/19.12Z IN RATHER GOOD AGREEMENT
WITH THE LARGE-SCALE FEATURES ACROSS NOAM WED...NAMELY LONGWAVE
TROUGHING OVER THE CENTRAL/WESTERN CONUS. BUT...PLENTY OF DETAIL
DIFFERENCES ON THE SHORTWAVE ENERGY RIPPLING THRU THIS TROUGH AND
INTO THE UPPER MIDWEST WED/WED NIGHT. THE LARGE-SCALE CONSISTENCY
REMAINS REASONABLE THU THRU SAT AS THE TROUGH FROM WED LIFTS INTO
THE CAN MARITIMES AND ANOTHER STRONG TROUGH DIGS INTO THE
CENTRAL/SOUTHERN ROCKIES. HOWEVER...LIKE WED THERE ARE PLENTY OF
DETAIL DIFFERENCES ON THE SHORTWAVE ENERGY RIPPLING THRU THE
GENERALLY PROGRESSIVE LONGWAVE FLOW. FORECAST CONFIDENCE FOR TUE
THRU SAT IS BELOW AVERAGE THIS CYCLE.

THIS PERIOD STARTS OUT WITH VARIOUS PIECES OF SHORTWAVE ENERGY IN
THE CENTRAL CONUS TROUGH PROGGED TO LIFT TOWARD/ACROSS THE REGION
WED/WED NIGHT. THE ATTENDANT SFC-850MB LOW WOULD GENERALLY PASS
ACROSS NORTHERN MN INTO ONT WITH THE FORECAST AREA ON THE WARM
SIDE OF THE SYSTEM. BULK OF THE LOWER LEVEL THERMO-DYNAMIC FORCING
WOULD PASS WEST/NORTH OF THE FORECAST AREA AS WELL. LOWER LEVEL
THERMAL PROFILE INDICATE ANY PRECIPITATION WED/WED EVENING MAINLY
AS -RA/-DZ...WITH SOME -SN POSSIBLE LATER WED NIGHT/THU MORNING AS
COLDER AIR WOULD WRAP IN BEHIND THE DEPARTING SYSTEM. THU WOULD
SEE THE MID LEVEL TROUGH AXIS EXIT EAST...WITH RISING HGTS OVER
THE REGION AHEAD OF THE NEXT STRONG TROUGH DIGGING INTO THE
ROCKIES. CONSENSUS WOULD DRIFT A WEAK RIDGE OF HIGH PRESSURE
ACROSS THE REGION LATER THU INTO FRI MORNING...FOR A DRY PERIOD.
ECMWF EJECTS A STRONGER PIECE OF ENERGY OUT OF THE WESTERN TROUGH
AND INTO THE UPPER MIDWEST ON CHRISTMAS DAY...WHILE GFS HAS BROAD
RIDGING ALOFT AND SFC HIGH PRESSURE OVER THE REGION. STRONGER
ECMWF SOLUTION FOR FRI IS ALSO A WARMER SOLUTION...WITH ANY OF ITS
PRECIPITATION CHANCES FRI AFTERNOON/NIGHT MAINLY AS RAIN. THE
TIMING DIFFERENCES KEEP THE MODELS AT ODDS SAT...AND A LOT
VARIABILITY SEEN AMONG ENSEMBLE MEMBERS AT DAYS 6/7. UNTIL THE
DETAILS SORT THEMSELVES OUT...THE SMALL CONSENSUS PRECIPITATION
CHANCES FRI- SAT OKAY FOR NOW. MODEL/ENSEMBLE CONSENSUS OF
HIGHS/LOWS RUNNING 5F TO 10F ABOVE NORMAL IN THE DAY 4-7 PERIOD
LOOK GOOD WITH THE CAN/ARCTIC AIR REMAINING BOTTLED UP WELL NORTH
IN CANADA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CST SAT DEC 19 2015

WILL START BOTH SITES WITH WIND SHEAR AND HAVE IT THROUGH THE
OVERNIGHT HOURS. THE 20.00Z NAM AND 20.03Z RAP CAME IN WITH
STRONGER WINDS ABOVE THE SURFACE AND THE 20.00Z SOUNDING FROM KOAX
DID SHOW 45 KNOTS AROUND 2500 FEET SO THE WINDS IN THE MODELS MAY
BE PRETTY REASONABLE. THE NAM ALSO CAME IN WITH A SLOWER TREND IN
BRINGING IN THE LOW LEVEL MOISTURE FOR THE MVFR/IFR
CEILINGS...WHICH THE RAP AGREED WITH...SO PUSHED THESE BACK TO
ABOUT THE MIDDLE OF THE AFTERNOON. THE FORECAST SOUNDINGS THEN
SHOW THE LOW LEVEL SATURATION DEPTH INCREASING TO AROUND 5000 FEET
WITH SOME LIFT THROUGH THIS FROM THE ONGOING ISENTROPIC UP GLIDE
FOR THE POSSIBILITY OF DRIZZLE. ADDED IT TO BOTH TAF SITES FOR
SUNDAY EVENING...BUT THE NAM AND THE HI-RES MESO MODELS SUGGEST
THERE IS THE POSSIBILITY THAT IT COULD MISS KRST.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04





AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 340 AM CST TUE DEC 22 2015

.SYNOPSIS...
ISSUED AT 337 AM CST TUE DEC 22 2015

WEAK SURFACE RIDGE IS BUILDING INTO THE AREA EARLY THIS AM.
SATELLITE AND OBS SHOW STRATUS BLANKETING THE ENTIRE AREA AND
MUCH OF THE MIDWEST... WITH THE BACK EDGE NEAR THE MISSOURI
RIVER VALLEY SHOWING LITTLE MOVEMENT HOLDING FIRM BENEATH STRONG
850 MB INVERSION. WEAK ISENTROPIC ASCENT AND WEAK CONVERGENCE
WITH SURFACE TROUGH PRODUCED PATCHY TO AREAS OF FOG AND DRIZZLE
LAST EVENING INTO THE OVERNIGHT... BUT SEEING A DIMINISHING TREND
EARLY THIS AM AS THIS LIFT MIGRATES EAST. WATER VAPOR SHOWS
UPPER LEVEL SHORTWAVE MOVING ACROSS THE UPPER MIDWEST WITHIN
SEMI-ZONAL FLOW PATTERN. MUCH STRONGER WAVE WAS NOTED OVER THE
NORTHERN ROCKIES IN LEFT EXIT REGION OF VIGOROUS UPPER LEVEL JET
NOSING FROM EASTERN PACIFIC INTO THE WESTERN CONUS. THIS SYSTEM
LOOKS TO SHIFT ACROSS THE UPPER MIDWEST ON WEDNESDAY BRINGING
OUR NEXT ROUND OF WET WEATHER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN CHALLENGES ARE CLOUD TRENDS AND IMPACT ON HIGHS... THEN RAIN
CHANCES LATER TONIGHT.

DONT FORESEE MUCH EROSION OF THE STRATUS THIS AM WITH SFC RIDGE
SLIDING ACROSS REGION WITH LIMITED MIXING AND STRONG 850 MB
INVERSION IN PLACE. HOWEVER... REMAINS TO BE SEEN WITH PASSAGE
OF THE MID LEVEL WAVE THIS AM IF INCREASING SUBSIDENCE IN WAKE
CAN HELP BRING ABOUT SOME EROSION AND NOTICING LAST FEW RUNS OF
HRRR DEPICT SOME DECREASE IN LOWER CLOUDS NORTH LATE AM INTO THE
PM. SATELLITE TRENDS ALSO SHOW LITTLE MOVEMENT TO BACK EDGE OF THE
STRATUS NEAR THE MISSOURI RIVER VALLEY EARLY THIS AM... AND SOME
OF THE HI-RES GUIDANCE IS PRETTY AGGRESSIVE IN ERODING THIS FROM
THE SOUTH THIS AFTERNOON INTO EASTERN IA AND WESTERN IL... BUT
NOTICING HRRR TRENDING SLOWER WITH THIS PROCESS AND WOULD SUGGEST
SOME EROSION UP TO OUR SOUTHERN CWA BUT MAINLY FURTHER SOUTH.
DO FEEL SOME EROSION OF STRATUS IS LIKELY ESPECIALLY ON THE WEST
AND SOUTH SIDE OF DECK WITHIN DEVELOPING STRONGER SOUTHERLY FLOW
AND MIXING... BUT ALSO EXPECT INCREASING HIGH CLOUDS AND WITH
THE FLOW GENERALLY SSE NOT FEELING GOOD ON PROSPECTS FOR MUCH IN
WAY OF SUNSHINE TODAY AND THUS STAYED WITH CLOUDY-MOCLDY SKY
FORECAST TODAY. AS A RESULT OF STAYING PESSIMISTIC WITH CLOUDS
LOWERED HIGHS A TOUCH AND SIDED ON COOL SIDE OF GUIDANCE BLEND
WITH RANGE AROUND 40 TO MID 40S. HOWEVER... IF NO LIFTING OR
THINNING OF STRATUS OCCURS THEN WILL BE COLDER AND MORE IN RANGE
OF MID 30S NORTH TO LOWER 40S SOUTH. ON THE OTHER SIDE OF THIS
IF WE WERE TO SEE MORE EROSION OF STRATUS THIS AFTERNOON WITH
ONSET OF GUSTY SSE WINDS AND BETTER MIXING THEN COULD EASILY SEE
HIGHS WELL INTO THE 40S TO LOWER 50S. BOTTOM LINE... AS CLOUD
TRENDS GO... SO GO TEMPS. TYPICALLY BETTER TO STAY CONSERVATIVE/
PESSIMISTIC WITH CLOUD AND TEMP TRENDS THIS TIME OF YEAR... AS
DECEMBER IS OUR CLOUDIEST MONTH.

AS FOR WINDS TODAY... SHOULD BECOME GUSTY BY AFTERNOON FROM S/SE
15-25 MPH... WITH TIGHTENING PRESSURE GRADIENT BETWEEN NORTHERN
PLAINS TO LEE SIDE CYCLONES AND GREAT LAKES HIGH PRESSURE RIDGE.
WINDS LIKELY TO REMAIN OCCASIONALLY GUSTY TONIGHT WITH CONTINUED
RAMPING UP OF LOW LEVEL JET AND LINGERING SFC PRESSURE GRADIENT.

ISENTROPIC ASCENT/WARM ADVECTION WITH STRENGTHENING LOW LEVEL JET
SHOULD FOSTER INCREASING SHOWER ACTIVITY OVERNIGHT... ESPECIALLY
WEST AND SOUTHWEST OF QUAD CITIES. CANT RULE OUT A RUMBLE OF
THUNDER ESPECIALLY FAR SOUTHWEST CWA WITHIN PLUME OF STEEP LAPSE
RATES 7-8C/KM IN 600-750 LAYER... BUT FEELING FAIRLY ISOLATED AND
HAVE LEFT OUT MENTION ATTIM.

TEMPS SHOULD DROP VERY LITTLE EARLY THIS EVENING AND PRETTY MUCH
BE STEADY TO GRADUALLY RISING TONIGHT WITH CONTINUED WARM
ADVECTION. DEPENDING ON WHAT TEMPS DO TODAY... ITS VERY POSSIBLE
TO SEE HIGHS FOR THE DAY SOME AREAS OCCUR THIS EVENING...
ESPECIALLY NORTHERN CWA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR
PRECIPITATION AND THE CHANGING GUIDANCE.  GUIDANCE HAS NOT SETTLED
ON ANY SOLUTIONS PAST TOMORROW.  THIS LEADS TO AN OVERALL POOR
CONFIDENCE IN THE FORECAST.  MAIN ISSUE WITH THIS IS THAT SOME OF
THE MODEL SOLUTIONS SUGGEST THE POTENTIAL FOR A SIGNIFICANT RAINFALL
EVENT BOTH WEDNESDAY AND AGAIN TOWARDS THE END OF THE WEEKEND. THESE
EVENTS...IF THEY OCCUR WOULD ONLY EXASPERATE AN ALREADY ATYPICAL
DECEMBER HYDRO EVENT.

WEDNESDAY...WEDNESDAY NIGHT...

MODELS ARE IN GOOD AGREEMENT WITH THE TRACK OF THE LOW ACROSS THE
AREA. MUCH LIKE YESTERDAY...TEMPERATURES WILL BE THE 40S TO 50S
ACROSS THE CWA AND MOISTURE STREAMS INTO THE AREA.  WITH PWATS WELL
ABOVE NORMAL AND APPROACHING 1 INCH ACROSS THE AREA...THE POTENTIAL
FOR MODERATE RAINFALL EXISTS.  IT APPEARS THAT WE ONCE AGAIN HAVE A
THREAT FOR THUNDERSTORMS WITH THIS SYSTEM AS THE CLEAR SLOT MAKES
ITS WAY INTO THE AREA.  LAPSE RATES SHOULD STEEPEN IN THE MIXED
PHASE REGION OF AN UPDRAFT...THIS INCREASES THE CHANCES FOR
THUNDER...ESPECIALLY SOUTH AND THEN EAST OF THE QC.  SPC HAS THIS
AREA IN A MARGINAL RISK FOR SEVERE WEATHER ON WEDNESDAY WITH THE
SLIGHT RISK NOT FAR TO OUR EAST.  MY GUT IS TELLING ME THAT THE BEST
CHANCE FOR SEVERE WILL BE WELL TO OUR EAST ASSOCIATED WITH THE H85
JET.  THAT BEING SAID...IF WE WERE TO GET SEVERE WEATHER IT WOULD BE
ASSOCIATED WITH THE CLEAR SLOT IN THE AFTERNOON.  HIRES MODELS
PREDICT A BROKEN LINE OF CONVECTION ALONG THIS INTERFACE.  I THINK
THAT HAIL WOULD BE THE MAIN THREAT IF SEVERE WEATHER OCCURRED.  I
ALSO THINK A BRIEF WEAK SPIN UP IS NOT OUT OF THE QUESTION.
AGAIN...I HAVE VERY LOW CONFIDENCE IN THIS OCCURRING.  WILL MENTION
THE MARGINAL RISK FOR SEVERE WEATHER IN THE HWO WITH THE HAIL THREAT
FOR WEDNESDAY.  ONCE THE SYSTEM MOVES OUT...THE GEM TRIES TO SNEAK
IN ANOTHER WAVE ALONG THE BOUNDARY OVERNIGHT.  I DO NOT THINK THIS
WILL HAPPEN AS IT IS THE OUTLIER OF THE REST OF THE MODELS.  AS SUCH
I DOWNPLAYED IT.  IF IT IS RIGHT...WE COULD SEE SOME SNOW
ACCUMULATION ACROSS NW ZONES.

THURSDAY THROUGH SATURDAY...

MODELS IN GOOD AGREEMENT FOR A QUIET CHRISTMAS EVE AND CHRISTMAS DAY
ACROSS THE AREA WITH HIGH PRESSURE ENTRENCHED ACROSS THE AREA.  THE
POTENTIAL EXISTS FOR SOME CLEARING AS WELL ON CHRISTMAS DAY.  AFTER
CHRISTMAS DAY...INTO SATURDAY...THE GFS AND ECMWF STALL A BOUNDARY
TO OUR SOUTH.  OVERRRUNING MOISTURE MAY GRAZE THE AREA WITH RAIN AND
EVEN SOME RAIN/SNOW MIX ACROSS THE FAR NORTH FRIDAY NIGHT INTO
SATURDAY.  FOR THE MOST PART THE HEAVIEST PRECIP STAYS TO THE SOUTH.
PAST THIS...THE MODELS DIVERGE.

PAST SATURDAY...

WITH GUIDANCE JUMPING RUN TO RUN PAST SATURDAY IM GOING TO DISCUSS
EACH MODELS GUIDANCE AND SUGGESTED OUTCOMES AND THEN DISCUSS WHY I
WENT A COMPROMISE BETWEEN THE GFS AND ECMWF.  NEEDLESS TO SAY...THE
EXTENDED FORECAST IS FULL OF BUSY WEATHER...AND IF THE GFS IS
CORRECT...WE COULD SEE AN ADDITIONAL 2 TO 4 INCHES AND POSSIBLY UP
TO 5 INCHES THROUGH THE NEXT TEN DAYS.

GFS...

THE RECENT GFS RUNS HAVE PUSHED AN EXTREMELY POTENT...NEGATIVELY
TILTED SYSTEM INTO THE AREA.  THIS PULLS A DEEP LOW ACROSS CENTRAL
IOWA.  WITH THE STALLED BOUNDARY TO OUR SOUTH...DEEP MOISTURE WOULD
QUICKLY SURGE INTO THE AREA.   60 DEGREE TEMPS ARE FORECAST FOR THE
FAR SE WITH THIS SYSTEM.  THE WARM SECTOR...WITH BACKED
WINDS...WOULD ROLL OVER THE AREA...LIKELY LEADING TO THUNDERSTORMS
AND INCREASED RAINFALL ACROSS THE AREA.  THE GFS HAS 1 TO 3+ INCHES
OF RAIN IN THIS EVENT.  IF THIS WERE TO OCCUR...WE WOULD LIKELY NOT
HAVE MUCH TIME FOR WATER FROM YESTERDAYS EVENT AND WEDNESDAY EVENT
TO ROUTE THROUGH THE RIVERS...MEANING HIGHER RIVERS AND POSSIBLY
INCREASED FLOODING.   THE NORTHERN EDGE OF THE CWA WOULD EXPERIENCE
A WINTRY MIX INTO SUNDAY NIGHT AND MONDAY MORNING.  AT THIS TIME
HAVE A RA/SN/PL MIX.  THIS SOLUTION WOULD BE THE WORST FROM A HYDRO
POINT OF VIEW.  I HAVE LOW CONFIDENCE IN THIS OCCURRING.

ECMWF...

THE EURO IS MUCH SLOWER AND ACTUALLY KEEPS THE LOW TO OUR SOUTH
LONGER.  THIS WOULD HELP TO ROUTE MORE WATER OUT OF THE FLOW.
EVENTUALLY ON TUESDAY...THE LOW LIFTS THROUGH THE AREA AND HAS LOWER
...LESS THAN AN INCH QPF...ALONG WITH IT.  THIS WOULD BE A MUCH
BETTER SOLUTION FROM A HYDRO POINT OF VIEW.  MY CONFIDENCE IS
SLIGHTLY HIGHER IN THIS SCENARIO THAN THE GFS...NONETHELESS IT IS
LOW.

THE BOTTOM LINE...

IM STRUGGLING TO DEVELOP THE CONFIDENCE TO TOTALLY ELIMINATE THE GFS
SOLUTION FROM NEXT WEEK. THE GFS HAS CONSISTENTLY DROPPED 1 TO 2
INCHES OF QPF ACROSS CENTRAL MO. A SMALL SHIFT NORTH INTO OUR AREA
IS NOT UNREASONABLE. HOWEVER...IT HAS JUMPED AROUND A LOT MORE
THAN THE EURO AS OF LATE. THIS IS WHY I AM OKAY WITH THE BLEND
THAT I HAVE. UNTIL THE MODELS AGREE ON A SOLUTION THIS WILL
CONTINUE. OBVIOUSLY THESE DIFFERENCES IN SOLUTION MEAN A MAJOR
DIFFERENCE IN POTENTIAL IMPACTS. WHILE I DONT WANT TO MINIMALIZE
THESE IMPACTS...IT IS IMPORTANT TO REMEMBER WE ARE ALMOST 7 DAYS
OUT. EXPECT CHANGES TO THE FORECAST FOR EARLY NEXT WEEK...SOME OF
THESE CHANGES COULD BE SIGNIFICANT...THAT IS THE BOTTOM LINE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1134 PM CST MON DEC 21 2015

OPTED FOR A SLOWER CLEARING TREND FOR 06Z TAF ISSUANCE BASED
MAINLY ON EVENING TRENDS OF ENTRENCHED STRATUS SHIELD. LOWEST
VISIBILITIES AND CEILINGS WILL CONTINUE AT KDBQ...AND CEILINGS
EXPECTED TO REMAIN IN PLACE THERE THROUGH TAF PERIOD. HAVE TIMED
PARTIAL CLEARING FROM 17Z TO 21Z...BEGINNING FIRST AT KBRL.

&&

.HYDROLOGY...
ISSUED AT 247 AM CST TUE DEC 22 2015

RAINFALL AMOUNTS OF A QUARTER INCH TO THREE QUARTERS OF AN INCH FELL
OVER THE PAST 24 HOURS GENERALLY SOUTH OF A LINE FROM MARENGO TO
BELLEVUE. WITH SATURATED GROUND...NEARLY ALL OF THIS RAINFALL WILL
BE RUNOFF AND HAVE ALREADY SEEN SOME LOCAL RESPONSES ON SOME OF THE
RIVERS. THIS ADDITIONAL RAINFALL WILL INCREASE THE FORECAST CRESTS A
BIT ON SOME RIVERS...AND HAS PUSHED THE FORECASTS FOR THE LOWER END
OF THE SKUNK AND DES MOINES RIVERS OVER FLOOD STAGE. ALONG THE
MISSISSIPPI...AFTER SEEING THE RIVER LEVELS FALL OR BECOME STEADY
OVER THE PAST 24 HOURS...MOST SITES WILL SEE THE RIVER BEGIN RISING
AGAIN...WITH THIS TREND CONTINUING THROUGH MUCH OF THE WEEK.

MOST FORECASTS ARE FOR THE RIVER LEVELS TO FALL BY THE END OF THIS
WEEK. HOWEVER...ADDITIONAL STORM SYSTEMS ARE LOOKING TO PASS ACROSS
THE AREA THROUGH THE NEXT WEEK WITH PRECIPITATION FALLING AS RAIN.
THE FIRST OF WHICH WILL BE WEDNESDAY. THERE IS QUITE A BIT OF
UNCERTAINTY IN HOW MUCH RAIN WILL FALL AND WHAT AREAS WILL GET HIT
YET...BUT LIKELY WILL BE ADDITIONAL RISES AND FURTHER POTENTIAL FOR
FLOODING ON SOME AREA RIVERS THROUGH THE CHRISTMAS HOLIDAY WEEKEND.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...MCCLURE
SHORT TERM...MCCLURE
LONG TERM...GIBBS
AVIATION...RP KINNEY
HYDROLOGY...GIBBS




AREA FORECAST DISCUSSION

NWS JACKSON KY

 101 AM EST TUE DEC 22 2015

.UPDATE...
ISSUED AT 101 AM EST TUE DEC 22 2015

WIDESPREAD LIGHT RAIN CONTINUES TO PUSH EAST ACROSS MUCH OF THE
AREA. THIS RAIN WILL QUICKLY PUSH EAST IN THE NEXT 2 TO 4 HOURS
WITH A BRIEF LULL PUSHING IN FROM THE WEST. HOWEVER...A LINE OF
SHOWERS AND EMBEDDED THUNDERSTORMS HAS DEVELOPED OUT WEST TOWARDS
BOWLING GREEN NORTH TO JUST WEST OF FRANKFORT. HRRR HAS THIS LINE
DEPICTED WELL IN THE LATEST FEW RUNS AND BRING THIS ACTIVITY UP
ACROSS THE BLUEGRASS COUNTIES SHORTLY AFTER 09Z. WE`LL HAVE TO
WATCH THIS AS WE MAY NEED TO TOSS IN SOME THUNDER FOR OUR NORTHERN
COUNTIES. NEXT UPDATE SHOULD HAVE A BETTER HANDLE ON THIS
POTENTIAL. HI-RES MODELS DO SHOW SOME WEAKENING IN THE NEXT FEW
HOURS...SO WE`LL SEE IF THAT MATERIALIZES. REGARDLESS...WE SHOULD
SEE A SECOND SURGE OF RAIN TOWARDS DAYBREAK...ESPECIALLY FOR AREAS
ALONG OR NORTH OF THE MOUNTAIN PARKWAY. FARTHER SOUTH...ACTIVITY
WILL LIKELY BE MORE ISOLATED OR SCATTERED AS THIS ACTIVITY PUSHES
IN AROUND DAYBREAK. LOOKS LIKE THE BULK OF TUESDAY SHOULD BE RAIN
FREE FOR MOST OF US WITH A JUST A FEW ISOLATED SHOWERS HANGING ON
ACROSS SOUTHEAST KENTUCKY THROUGH THE DAY. UPDATED FORECAST HAS
ALREADY BEEN SENT.

UPDATE ISSUED AT 929 PM EST MON DEC 21 2015

RAIN CONTINUES TO INCREASE IN COVERAGE AS IT MAKES ITS WAY INTO
EASTERN KENTUCKY. DECIDED TO INCREASE THE POPS ACROSS EASTERN KY
TO ALL NUMEROUS OR DEFINITE THROUGH THE REMAINDER OF THE EVENING.
IT SEEMS AS THOUGH THUNDER HAS CEASED ACROSS THE OHIO VALLEY...BUT
DID LEAVE IN ONE HOUR OF ISOLATED THUNDER IN THE AREA OF HIGHEST
POPS...JUST IN CASE WE HEAR ONE ROGUE RUMBLE OF THUNDER IN THE
HEAVIEST SHOWERS. ALSO LOOKED AT RADAR TRENDS AND NEW MODEL
GUIDANCE TO EXTRAPOLATE THE RAIN ACROSS THE REGION THROUGH THE
REMAINDER OF THE NIGHT...EXITING DURING TOMORROW MORNING.
ALSO...MADE SURE THE NEAR TERM FORECAST FOR TEMPS...DEW
POINTS...AND WINDS WERE REFLECTING THE ONGOING CONDITIONS. ALL
UPDATES WERE PUBLISHED AND SENT TO NDFD/WEB. A NEW ZONE FORECAST
PACKAGE WAS ALSO SENT OUT AS WELL TO REFLECT THESE CHANGES.

UPDATE ISSUED AT 743 PM EST MON DEC 21 2015

COVERAGE OF SHOWERS IS INCREASING AT A FASTER RATE THAN WAS
PREVIOUSLY FORECAST...SO WENT AHEAD AND INCREASED POPS ACROSS THE
CWA THROUGH THE EVENING. STILL LOOKING AT HEAVIEST SHOWERS TO
BEGIN MOVING INTO THE REGION OVER THE NEXT SEVERAL HOURS AND
CONTINUING THROUGH THE OVERNIGHT. THERE IS SOME THUNDER ONGOING
ACROSS SOUTH CENTRAL KY...SO WILL CONTINUE TO MONITOR AS IT NEARS
THE JKL CWA TO MAKE SURE THUNDER DOES NOT NEED TO BE ADDED INTO
OUR FORECAST AS WELL. OTHER UPDATES INCLUDED CHANGING THE WEATHER
FROM PROBABILITY TO COVERAGE...SINCE THERE IS ONGOING RAIN AND
ONLY CHANCE WORDING. CARRIED THE COVERAGE WORDING THROUGH THE DAY
TOMORROW AS WELL. ALSO...LOADED THE LATEST OBSERVATIONS FOR
TEMPS...DEW POINTS...AND WINDS INTO THE NEAR TERM FORECAST TO MAKE
SURE THE GRIDS REFLECTED THE ONGOING CONDITIONS. ALL CHANGES WERE
PUBLISHED AND SENT TO NDFD. A NEW FORECAST PACKAGE WAS ALSO SENT
OUT TO REFLECT THE ABOVE CHANGE.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 340 PM EST MON DEC 21 2015

OUR REGION IS IN A BROAD AREA OF WARM/MOIST ADVECTION OFF THE GULF
OF MEXICO WITH ROUNDS OF SHOWERS. ONE ROUND MOVED THROUGH THIS
MORNING...AND ANOTHER IS SLOWLY MAKING ITS WAY SE ACROSS THE
FORECAST AREA THIS AFTERNOON. THESE SHOWERS HAVE SHOWN AN OVERALL
VERY SLOW DECLINE AS SHORTWAVE ENERGY WHICH ENHANCED THEM EARLIER
RACES AWAY TO THE NE. ANOTHER SHORTWAVE TROUGH OVER THE MIDDLE OF
THE NATION IS INTERACTING WITH THE WARM/MOIST FLOW OFF THE GULF TO
CAUSE SHOWERS AND THUNDERSTORMS OVER THE LOWER MISSISSIPPI VALLEY
THIS AFTERNOON. MODELS SHOW THIS AREA OF PRECIP QUICKLY EXPANDING
NE LATE TODAY AND TONIGHT AS THE SHORTWAVE AND A SURFACE COLD
FRONT APPROACH. THIS WILL BRING SHOWERS TO THE JKL FORECAST AREA
TONIGHT. MOST OF THE PRECIP SHOULD BE ON THE WAY OUT TO THE NE
EARLY TUESDAY MORNING AS THE SHORTWAVE DEPARTS. THE COLD FRONT IS
EXPECTED TO STALL AS IT REACHES THE JKL FORECAST AREA...AND NO
SIGNIFICANT CHANGE IN OUR UNSEASONABLY WARM SURFACE AIR MASS
SHOULD OCCUR. ANOTHER MID/UPPER LEVEL IMPULSE WILL SUPPORT AN
EXPANDING SURFACE LOW PRESSURE SYSTEM OVER THE MIDDLE OF THE CONUS
ON TUESDAY AND TUESDAY NIGHT. THIS WILL STRENGTHEN LOW LEVEL FLOW
OFF THE GULF OF MEXICO AND SEND THE SURFACE BOUNDARY BACK NORTH.
MEANWHILE... ANOTHER UPPER LEVEL IMPULSE...CURRENTLY OVER NORTHERN
MEXICO...IS SHOWN BY ALL MODELS TO MOVE RAPIDLY THROUGH THE FLOW
ALOFT TO PASS NE OVER THE SE CONUS ON TUESDAY NIGHT. THIS SHOULD
BRING YET ANOTHER ROUND OF SHOWERS FOR THE JKL FORECAST
AREA...ESPECIALLY IN OUR SE COUNTIES.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 347 PM EST MON DEC 21 2015

THE EXTENDED PORTION OF THE FORECAST BEGINS ON WEDNESDAY WITH AN
ACTIVE UPPER LEVEL PATTERN IN PLACE. A DEEP TROUGH SLOWLY MOVING
ACROSS THE MS VALLEY AND INTO THE GREAT LAKES WILL BRING SEVERAL
STRONG SHORT WAVES TRACKING NORTHEAST THROUGH THE OH VALLEY. IN
FACT...A STRONG RIDGE OVER THE ATLANTIC WILL KEEP THE LONG WAVE
TROUGH OVER THE CENTRAL CONUS WITH THE LEE SIDE OVER THE APPALACHIAN
RANGE THROUGH THE ENTIRE EXTENDED.

AT THE SURFACE...SOUTHERLY FLOW WILL BE IN PLACE ACROSS KENTUCKY AS
ANOTHER LOW DEVELOPS IN THE PLAINS AND TRACKS NORTHEAST INTO THE
MIDWEST AND GREAT LAKES REGION WITH A WARM FRONT SHIFTING NORTH
AND POSITIONING OVER THE GREAT LAKES AS WELL PUTTING EASTERN
KENTUCKY IN THE WARM SECTOR IN A VERY UNSEASONABLY WARM AND MOIST
PATTERN FOR DECEMBER. A PREFRONTAL WAVE AHEAD OF THE MAIN TROUGH
WILL KEEP ENOUGH LIFT IN PLACE FOR ONGOING SHOWERS THROUGH THE
DAY ON WEDNESDAY BEFORE FRONTAL PRECIP ARRIVES LATE WEDNESDAY
AFTERNOON AND INTO THE EVENING. DECENT FORCING AND ELEVATED INSTABILITY
WITH THIS FEATURE WILL BE ENOUGH FOR THUNDERSTORM DEVELOPMENT AS
WELL AS A FEW MARGINALLY STRONG STORMS. DETAILS ARE A BIT UNCLEAR
AT THIS POINT BUT THE AMOUNT OF SHEAR AVAILABLE WILL POSE SOME
MONITORING.

THE FRONT MOVES THROUGH BUT STALLS OVER THE APPALACHIAN RANGE BY
LATE THURSDAY WITH CONTINUED RAINFALL ACROSS THE AREA. THIS RESULT
IN A BRIEF REPRIEVE IN THE PRECIP INTO THURSDAY NIGHT BEFORE
YET ANOTHER WAVE TRACKS ALONG THE FRONT INTO FRIDAY BRINGING
ANOTHER ROUND OF RAINFALL TO THE AREA. LOW PRESSURE DEVELOPS
ALONG THE LOWER MS VALLEY AND TRACKS NORTHEAST BRINGING ANOTHER
WARM FRONT NORTH THROUGH KENTUCKY FOLLOWED BY ANOTHER ROUND OF
WARM AND WET WEATHER THROUGH THE AREA FRIDAY AND INTO SATURDAY.
AS THE MENTIONED SURFACE LOW DEVELOPS OVER THE LOWER MS
VALLEY...MODELS HINT AT A STRONG UPPER LEVEL CLOSED LOW EJECTING
OUT OF THE 4 CORNERS REGION INTO THE SOUTHERN PLAINS FURTHER
DEVELOPING A STRONG FRONTAL SYSTEM OVER THE MS VALLEY HEADING
INTO SUNDAY AND INTO THE NEW WEEK.

WHILE MODELS DIVERGE INTO THE EXTENDED...THE OVERALL TREND INTO THE
EXTENDED IS RECORD WARMTH FOLLOWED BY PROLONGED WET WEATHER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 101 AM EST TUE DEC 22 2015

WHILE CIGS HAVE GONE VFR ACROSS EASTERN KENTUCKY PRESENTLY...LOW
LEVEL MOISTURE SHOULD SPREAD BACK INTO THE AREA THROUGH
DAYBREAK...WITH CIGS COMING BACK DOWN TO MVFR LEVELS GENERALLY
BETWEEN 1-2K FEET. LIGHT SOUTHERLY WINDS WILL GRADUALLY SHIFT TO
THE SOUTHWEST AFTER DAYBREAK...BUT ARE NOT EXPECTED TO GET GUSTY.
A BAND OF SHOWERS/STORMS WILL PUSH INTO THE BLUEGRASS TOWARDS
DAYBREAK AND COULD IMPACT KSYM...WHICH WILL NEED TO BE UPDATED TO
INCLUDE THUNDER IF IT HOLDS TOGETHER. OTHERWISE...EXPECT JUST SOME
ISOLATED SHOWERS AS WE HEAD THROUGH TUESDAY WITH CIGS LIFTING
SLIGHTLY...BUT LIKELY STAYING MVFR. THERE IS A SMALL CHANCE WE
COULD SEE SOME PARTIAL CLEARING...BUT GIVEN THE TIME OF
YEAR...ODDS ON THIS ARE VERY LOW.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...KAS
SHORT TERM...HAL
LONG TERM...SHALLENBERGER
AVIATION...KAS



AREA FORECAST DISCUSSION

NWS NEW ORLEANS LA

 356 AM CST TUE DEC 22 2015


.SHORT TERM...
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST
THIS MORNING. THIS 00Z SOUNDING FROM YESTERDAY AFTERNOON HAD A
RECORD HIGH PRECIP WATER VALUE OF 1.92" WHICH IS PROBABLY IN THE
UPPER 90TH PERCENTILE FOR THE ENTIRE MONTH OF DECEMBER. THUS
SHOULDN/T BE ANY SURPRISE THAT WIDESPREAD FOG HAS DEVELOPED OVER
MUCH OF THE AREA. MANY OBSERVATIONS INDICATE VISIBILITIES OF
AROUND A HALF MILE OR LESS. SAMPLING INTERSTATE CAMERAS ALSO SHOWS
WHAT APPEARS TO BE LESS THAN 1/4 MILE VISIBILITIES IN SOME
LOCATIONS AS WELL. ALTHOUGH THE ENTIRE CWA PROBABLY DOES NOT NEED
A DENSE FOG ADVISORY...LEAVE THEM ABSENT WOULD PRODUCE A VERY ODD
LOOKING AND CONFUSING PRODUCT. SO WILL BE ISSUING A BLANKET DENSE
FOG ADVISORY FOR THE CWA THROUGH 15Z.

CURRENT RADAR SHOWS FIRST WAVE HEADED EAST ACROSS THE NORTHERN GULF
WATERS. LINGERING SHOWERS PERSIST SIMPLY DUE TO COLUMN SATURATION
AND MINIMAL BUOYANCY. EXTENSIVE CLOUD COVER SHOULD LIMIT WARMING
TODAY TO LOWER 70S ACROSS THE FORECAST AREA. THIS IS A GOOD THING AS
IT WILL LIMIT INSTABILITY POTENTIAL. NEVERTHELESS...A SHORT WAVE IS
PROGGED TO LIFT NORTHEAST OUT OF THE GULF ACROSS THE LOWER HALF OF
THE CWA. HRRR AND NMM AS WELL AS MEDIUM RANGE MODELS ALL PINGING ON
A LARGE SWATH OF NUMEROUS SHOWERS AND THUNDERSTORMS IMPACTING AREAS
SOUTH OF INTERSTATE 10. THE FORECAST POPS HAVE THUS BEEN ADJUSTED
FOR THIS. THE SEVERE POTENTIAL WILL REMAIN ON THE LOW SIDE BUT STILL
EXISTS. MODEL SOUNDINGS DO INDICATE ELEVATED INSTABILITY ACROSS THE
BOARD BUT A WEAK WIND FIELD DURING THE DAYTIME. GOING INTO THE NIGHT
THE WIND FIELD BEGINS TO INCREASE WITH SHEAR VALUES IN THE 40 TO 50
KNOT RANGE. THE QUESTION IS WHETHER OR NOT CELLS WILL BE SURFACE
BASED. IF MODEL SOUNDINGS HOLD TRUE...THEY WONT BE AND THUS THE ONLY
CHANCE TO MIX DOWN STRONGER WINDS THROUGH THE WARM NOSE IS THROUGH
PRECIP LOADING. WILL BE SOMETHING TO WATCH BUT NOT A HIGH CONCERN.
MARINE LOCATIONS WILL BE THE MOST LIKELY FOR STRONGER WIND GUSTS AND
WATERSPOUTS.

THE REAL SEVERE WEATHER THREAT LOOKS TO COME INTO PLAY ON WEDNESDAY.
BROAD LONG WAVE TROUGH ALREADY IN PLACE OVER THE ROCKIES WILL DIG
AND SWING NEGATIVE OVER THE CENTRAL PLAINS DURING THE DAY. DOWN AT
THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
AROUND 1006 MB. TIGHTENING OF THE PRESSURE GRADIENT WILL INCREASE
SURFACE WINDS WHICH WILL THEN AIDE IN THE TRANSPORT OF 70 DEGREE
DEWPOINTS TO POINTS NORTH. PRESUMING THAT SFC TEMPS DO REACH MID 70S
WHILE THESE DEWPOINTS RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP
DURING THE DAY. BOTH GFS AND NAM BUFR SOUNDINGS SHOW SB AND PARCEL
CAPE VALUES OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE
CWA. HELICITY VALUES AREN/T THAT IMPRESSIVE AT 200 M2/S2 BUT
SUFFICIENT. NOT SURPRISING WITH A FAIRLY UNIFORM WIND DIRECTION
THROUGHOUT THE COLUMN. OF MORE IMPORTANCE IS SPEED SHEAR AND JUST
THE VALUE OF THE WINDS THEMSELVES. LOOKING AT 40 TO 50 KNOTS IN THE
BOUNDARY LAYER WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THE
PRECIP WATER VALUE IS IN A PRETTY NICE SWEET SPOT...NOT TOO HIGH AND
NOT TO LOW AT AROUND 1.5 INCHES. ALL OF THAT IS TO SAY THAT THE ODDS
OF SEVERE WEATHER FOR THE DAY WEDNESDAY LOOKING BETTER AND BETTER.
THE MAIN THREATS WILL BE TORNADOES AND DAMAGING WINDS. HOW
WIDESPREAD REMAINS TO BE SEEN. IF SFC TEMPS DONT WARM ENOUGH...WILL
JUST HAVE THE DYNAMICS. IF SOUTHEASTERLY FLOW IS TOO STRONG THAN THE
MARINE LAYER COULD BE PUSHED TOO FAR INLAND AND A WARM NOSE (SHOWN
CLEARLY ON THE GPT SOUNDING) WILL HINDER SFC BASED STORMS.
REGARDLESS...THE POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SPC
SLIGHT FOR THE AREA.


.LONG TERM...
RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR CONVECTION ON
THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD HAVE NO
PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW THUNDERSTORMS.
MUCH WEAKER WINDS IN THE COLUMN AND NON-SEVERE CONDUCING WIND
DIRECTIONS WILL LIMIT THE STRENGTH OF ACTIVITY. COVERAGE SHOULD
STILL BE OVER 50 PERCENT FOR THE MOST PART.

CHRISTMAS DAY COULD ACTUALLY HAVE THE LOWEST CHANCE OF RAIN FOR THE
ENTIRE WEEK AS UPPER LEVEL RIDGE CENTERED OVER THE WESTERN ATLANTIC
BUILDS BACK WESTWARD ACROSS THE CWA. PROBLEM IS THAT ITS STILL
CHANCE CATEGORY. ON THE TEMPERATURE SIDE OF THINGS...WILL NOT BE
FEELING TOO WINTER-LIKE WITH LOWS IN THE MID 60S AND HIGHS
APPROACHING 80 DEGREES IN ISOLATED LOCATIONS. A LITTLE PERSPECTIVE
ON HOW WARM IT WILL BE...THE FORECAST LOWS FOR CHRISTMAS DAY MORNING
ARE SEVERAL DEGREES WARMER THAN TYPICAL DAYTIME HIGHS FOR THIS TIME
OF YEAR. MAY NOT BREAK RECORDS BUT NOT TOO FAR OFF EITHER.

POPS TO FALL EVEN MORE DOWN INTO THE 20 TO 30 PERCENT RANGE THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. DIDNT MAKE ANY SIGNIFICANT CHANCES TO POPS DUE TO CHANGING
SOLUTIONS WITH EACH MODEL ITERATION.

MEFFER
&&




.AVIATION...

FOG WILL BE THE ISSUE FOR A FEW TERMINALS THIS MORNING. THE
PROBLEMS THAT DENSE FOG WILL DEVELOP FOR A VERY SHORT DURATION THEN
LIFT JUST AS QUICK. HAVE SET PREVAILING TO SHOW VIS AT 2 TO 3SM WITH
TEMPO GROUPS SHOWING DOWN TO 1/4SM. WILL ALSO SHOW TS FOR BTR...HDC
AND ASD MAINLY DURING THE EARLY AFTERNOON. A SEPARATE COMPLEX WILL
AFFECT THE SOUTH SHORE TERMINALS FROM HUM TO NEW AND MSY THROUGH TO
GPT LATE IN THE AFTERNOON AND EVENING HOURS. WILL ALSO KEEP FOG IN
12Z TAF PACK.

&&

.MARINE... TS WILL BE RESPONSIBLE FOR PRODUCING SOME STRONG WIND
SPEEDS OVER THE COASTAL WATERS THROUGH TONIGHT. AVOID ANY AREAS
WHERE ARE LOCATED. LARGER SCALE WINDS SHOULD BEGIN TO INCREASE OVER
THE OUTER WATERS TONIGHT WITH EXERCISE CAUTION/SMALL CRAFT ADVISORY
HEADLINES LIKELY TO BE NECESSARY ON WEDNESDAY. CONDITIONS SHOULD
EASE A BIT ON THURSDAY WITH RELATIVELY QUIET WEATHER UNTIL NEXT
SUNDAY AHEAD OF A STRONGER SYSTEM MOVING THROUGH THE CENTER OF THE
COUNTRY.

&&

DECISION SUPPORT...

DSS CODE....GREEN. DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.

DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN  = NO WEATHER
IMPACTS THAT REQUIRE ACTION BLUE   = LONG FUSED
WATCH/WARNING/ADVISORY IN EFFECT OR HIGH         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
        ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO
MODERATE RISK SEVERE; NEARBY         TROPICAL EVENTS; HAZMAT OR
OTHER LARGE EPISODES RED    = FULL ENGAGEMENT FOR MODERATE RISK SVR
AND/OR DIRECT         TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  72  63  76  66 /  70  80  90  60
BTR  74  64  75  66 /  80  80  90  40
ASD  71  64  74  67 /  90  80  90  70
MSY  72  64  75  70 /  90  90  80  70
GPT  70  64  71  68 /  90  80  90  70
PQL  72  64  73  69 /  90  80  90  70

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR LAZ034>037-
     039-040-046>050-056>072.

GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR GMZ530-532-
     534-536-538-550-552-555.

MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ068>071-
     077-080>082.

GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR GMZ532-534-
     536-538-550-552-555.

&&

$$




AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 1153 PM CST MON DEC 21 2015

.SHORT TERM: (Through Tuesday Afternoon)
Issued at 120 PM CST Mon Dec 21 2015

The cold front is making steady progress east across the area
with falling temperatures and a wind shift to the west-northwest.
Dry slot and breaks in the overcast allowed St. Louis to top out
at 67 degrees late this morning which tied the record for the
date that was set back in 1967. What a way to start astronomical
winter, which officially begins at 10:48 PM this evening!

Post frontal IFR stratus deck will blanket the CWA this evening and
despite the subsidence behind the storm system, the low level
moisture will be trapped under the inversion and keep the cloud deck
around tonight or allow for dense fog to develop if there is
clearing. HRRR has been very reliable in these post frontal cloud
forecasts as of late and it shows a LIFR cloud deck through at least
14Z on Tuesday.

Believe clouds or fog will try to scatter/dissipate from
southwest to northeast on Tuesday as flow becomes southerly. Have
forecast temperatures a bit cooler for Tuesday across the
northeastern half of the CWA due to this expected cloud cover.

CVKING

.LONG TERM:  (Tuesday Night through Next Monday)
Issued at 120 PM CST Mon Dec 21 2015

Active weather pattern sets up Tuesday night through the
remainder of the forecast. Next shortwave and attendant surface
low/cold front is expected to approach the area from the west
Tuesday night and move across the CWA by late Wednesday evening.
Moisture advection is forecast to increase Tuesday night as the
low level jet increases and showers should be on the increase
after midnight. Can`t rule out a few rumbles of thunder as well,
given MUCAPES around 500 J/KG. This first round of "warm
advection precipitation" should move northeast by late morning on
Wednesday and depending on the amount of clearing and
destablization that can take place across the eastern half of the
CWA, severe thunderstorms may develop ahead and along the cold
front. As with almost any cold season event, the shear and
helicity values are extremely favorable for organized convection.
The question will be the surface based instabilty. The NAM is the
most bullish with around 500-750 J/KG. SPC has placed the eastern
portion of the CWA in a Marginal Risk for Day 3, and historical
analogs (St. Louis University CIPS) certainly support this. Have
introduced severe wording in the HWO and Situational Report to
account for this potential.

Needless to say temperatures will be well above average Tuesday
night and Wednesday. Some of the guidance actually has 70s on
Wednesday afternoon. I would think that is a tad too high, but we
got up to 67 degrees today so I suppose anything is possible this
winter!

The storms, if they develop, should exit rapidly to the east
Wednesday night leaving Christmas Eve and much of Christmas Day dry
and cooler (but yes, still above normal).

Attention then turns to a prolonged rain event Christmas night
through the Holiday Weekend with the prospect of flooding. The
synoptic setup is that the front that drifted to our south moves
back north and sits just to the south of us for a few days with a
classic setup for elevated convection as a deep trof and surface low
develop to our southwest. The front lifts north by early next week
with the system moving over the top of us. GFS has a maximum of
7-10 inches of rain from southwest Missouri through the St. Louis
Metro, the ECWMF has 4-6 inches, and the Central Region SuperBlend
of model data (which includes WPC) has widespread amounts of 5-7
inches. This amount of rain, even spread out over several days,
will cause local streams, creeks and rivers to flood. If
convection occurs and locally higher amounts are realized, then
flash flooding could be a possibility toward the end of the event
once the ground has been thoroughly saturated. Given these
concerns have decided to add mention of flooding in both the HWO
and Situation Report.

Temperatures will remain above normal and fluctuate depending on the
exact placement of the front during the extended portion of the
forecast.

CVKING

&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1139 PM CST Mon Dec 21 2015

IFR flight conditions over most of Missouri and west central
Illinois will overspread the remainder of the area through the
remainder of the night. Expect lowest ceilings/vsbys over central
MO where ceilings will likely be at or below 500 ft. If there is
any clearing, the setup for fog is excellent, so the stratus may
turn into a dense fog with vsbys at or below 1SM. Did not mention
the lower visibility in the KCOU TAF as I`m not sure there will be
any clearing at this time. Low flight conditions will persist
Tuesday morning...with lifting and scattering clouds from the
west during the late morning or early afternoon. Wind will turn to
the south-southeast ahead of the next storm system allowing clouds
to build back into the area during the evening. Looks like the
best chance for rain will hold off until after 06Z

Specifics for KSTL:
Ceiling just dropped below 900 ft right before I sent the
TAF...and I expect IFR ceilings to prevail at Lambert until at
least mid morning Tuesday. Guidance is forecasting the ceilings to
lift and scatter out Tuesday afternoon, but I think it`s too quick
given the moist low levels and weak December sunshine. Therefore I
opted to keep the ceilings below 2000 ft until mid afternoon. If
there is a period of VFR Tuesday afternoon, I think it will be
short-lived. South-southeast flow will develop and push abundant
low level clouds back into the region...along with showers and
possibly a few thunderstorms after 06Z.

Carney

&&

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

$$

WFO LSX




AREA FORECAST DISCUSSION

NWS BUFFALO NY

 1134 PM EST MON DEC 21 2015

.SYNOPSIS...
A BROAD SOUTHWEST FLOW ACROSS THE EASTERN HALF OF THE COUNTRY WILL
GENERALLY SUPPORT UNSETTLED WEATHER INTO CHRISTMAS EVE. PERIODIC
RAIN SHOWERS WILL BE ACCOMPANIED BY SIGNIFICANT DAY TO DAY WARMING
WITH NEAR RECORD TEMPERATURES IN THE 60S FORECAST FOR WEDNESDAY AND
THURSDAY. THESE EL NINO DRIVEN TEMPERATURES WILL BE ABOUT 30 DEGREES
ABOVE NORMAL...OR CLOSE TO LEVELS EXPERIENCED DURING THE FIRST HALF
OF OCTOBER.

&&

.NEAR TERM /THROUGH TUESDAY/...
THE REGION WILL BE IN A SOUTHWESTERLY FLOW THROUGH TUESDAY...WITH
LONGWAVE TROUGHING FROM THE PACIFIC COAST TO THE PLAINS. THE FIRST
OF TWO SHORTWAVES HAS EXITED INTO NORTHERN NEW ENGLAND LATE THIS
EVENING.

AT 1100 PM RADAR SHOWS SCATTERED SHOWERS LIFTING ACROSS LAKE
ONTARIO AND THE EASTERN LAKE ONTARIO REGION...WITH THESE HIT OR
MISS SHOWERS EXPECTED TO CONTINUE TO LIFT NORTH LATE THIS EVENING.
AFTER THIS THERE MAY BE A SPOTTY SHOWER OR DRIZZLE...BUT FOR THE
MOST PART IT SHOULD BE DRY. ANOTHER...MORE POTENT WAVE...WILL LIFT
FROM THE TENNESSEE VALLEY INTO OUR REGION LATE TONIGHT AND ACROSS
OUR REGION ON TUESDAY. THE 00/18Z GUIDANCE HAS TRENDED HIGHER WITH
QPF...AND BOTH RADAR TRENDS AND THE HRRR SUPPORT THIS. BUFKIT
SHOWS THE BEST LIFT WILL BE ALOFT...LIKELY WITH THE SHORTWAVE AND
AIDED BY A FAVORABLE JET QUADRANT. AS A RESULT...EXPECT A RATHER
STEADY AREA OF RAIN TO ENTER SOUTHERN PORTIONS LATE TONIGHT AND TO MOVE
ACROSS WESTERN NEW YORK TUESDAY MORNING BEFORE CROSSING THE
EASTERN LAKE ONTARIO REGION LATE TUESDAY MORNING AND EARLY
AFTERNOON. THIS MAY BRING A HALF INCH OF RAIN TO A CORRIDOR
EXTENDING FROM WELLSVILLE TO SYRACUSE WITH A QUARTER INCH MORE
COMMONPLACE ELSEWHERE. POPS REFLECT THE SAME TRENDS AS BEFORE BUT
ARE A BIT MORE DEFINITIVE.

TEMPERATURES WILL REMAIN STEADY OR SLOWLY RISE OVERNIGHT. CLOUDY
SKIES WILL LIMIT ANY RADIATIONAL COOLING...AND 850MB TEMPERATURES
WILL GRADUALLY WARM THROUGH THE PERIOD. EVEN WITH RAIN AND MOSTLY
CLOUDY SKIES TEMPERATURES ON TUESDAY WILL CLIMB DUE TO WARM AIR
ADVECTION AND RISE INTO THE 50S IN MOST LOCATIONS.

EXPECT FOG TO DEVELOP IN SOME AREAS TONIGHT...ESPECIALLY
IN AREAS WHERE THERE IS SNOW ON THE GROUND. THIS IS DUE TO DEW
POINTS RISING TO WELL ABOVE 32 AND DIMINISHING WINDS.

SPEAKING OF WINDS...WINDS ALOFT WILL DIMINISH THIS EVENING WHICH
WILL RESULT IN LESS GUSTY WINDS THROUGH TUESDAY MORNING. WINDS
ALOFT ARE NOT VERY STRONG...BUT THE TRACK OF THE SURFACE LOW IS
FAVORABLE TO MIX 925MB WINDS TO THE SURFACE WITH THE PASSAGE OF
THE LOW WITH SOME GUSTS TO 35 MPH ACROSS THE NIAGARA FRONTIER
TUESDAY AFTERNOON.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
EVENING UPDATE... LATEST MODELS SHOW WARM FRONT LIFTING NORTH ACROSS
THE FORECAST AREA ON WEDNESDAY AFTERNOON WITH OUR REGION RESIDING
WITHIN THE WARM SECTOR WEDNESDAY NIGHT BEFORE A COLD FRONT SWEEPS
ACROSS THURSDAY. THIS WILL HAVE AN IMPACT ON OUR TEMPS WITH THE
POTENTIAL FOR THE WARMEST TO BE LATER WEDNESDAY INTO WEDNESDAY NIGHT
BEFORE COOLING ON THURSDAY. EVEN WITH THIS SCENARIO WE STILL HAVE
THE POTENTIAL TO BREAK RECORD HIGHS BOTH WEDNESDAY AND THURSDAY WITH
HIGHEST TEMPS OCCURRING OVERNIGHT BRIDGING BOTH DAYS. HAVE ADJUSTED
THE HOURLY TEMP FORECAST TO REFLECT A NON-DIURNAL CURVE WEDNESDAY
NIGHT WHILE BUMPING HIGHS ON WEDNESDAY AND LOWERING A TOUCH ON
THURSDAY BASED ON QUICKER FRONTAL TIMING. THE REST OF THE FORECAST
REMAINS IN TACT.

PREVIOUS DISCUSSION... A HIGHLY AMPLIFIED PATTERN WILL CONTINUE TO
CHARACTERIZE THE MIDDLE OF THE WEEK WITH A FULL-LATITUDE TROUGH
CENTERED ON THE GREAT PLAINS. A POWERFUL UPPER LEVEL JET DIVING
ACROSS THE WESTERN U.S. WILL SERVE TO FURTHER AMPLIFY THIS
FEATURE...ENHANCING MERIDIONAL FLOW ACROSS THE EASTERN U.S. WHILE
DIRECTING A SERIES OF DISTURBANCES NORTHWARDS TOWARDS THE GREAT
LAKES. ALL OF THIS WILL TRANSLATE INTO A PERIOD OF UNSETTLED WEATHER
AND RECORD WARMTH ACROSS WESTERN AND NORTH-CENTRAL NEW YORK AS WE
APPROACH THE CHRISTMAS HOLIDAY. WE WILL DELVE FURTHER INTO THE
DETAILS BELOW...

THE PERIOD WILL OPEN ON A QUIET NOTE TUESDAY NIGHT AS THE AREA WILL
BE UNDER THE INFLUENCE OF SHORTWAVE RIDGING ALOFT...KEEPING
CONDITIONS DRY. WINDS WILL BACK TO THE SOUTH OVERNIGHT AS THE REGION
COMES UNDER THE INFLUENCE OF THE INCREASING MERIDIONAL FLOW DESCRIBED
ABOVE. THIS WILL PUMP INCREASINGLY WARM AND MOIST AIR ACROSS THE
LOWER GREAT LAKES WITH LOWS IN THE MID 40S TUESDAY NIGHT.
TEMPERATURES ON WEDNESDAY WILL REACH INTO THE UPPER 50S AND TOUCH 60
DEGREES ALONG LAKE ERIE...WHERE SOUTHEASTERLY DOWNSLOPING WILL AID
IN BOOSTING TEMPS. THIS WILL BE CLOSE ENOUGH TO AT LEAST TIE RECORD
HIGHS IN MANY LOCALES.

IN ADDITION TO THE POTENTIAL RECORD WARMTH WEDNESDAY...WE WILL SEE A
DECENT CHANCE FOR SHOWERS ACROSS MUCH OF THE FORECAST AREA BY
WEDNESDAY AFTERNOON AS A SHORTWAVE EJECTING OUT OF THE SOUTHERN
APPALACHIANS CROSSES CENTRAL NEW YORK. WHILE THERE MAY BE A
RESPITE BETWEEN SHOWERS ASSOCIATED WITH THIS INITIAL SHORTWAVE
WEDNESDAY AND SHOWERS ASSOCIATED WITH A FRONTAL SYSTEM ON
THURSDAY...GIVEN SOME UNCERTAINTY IN TIMING AND PLACEMENT OF
DETAILS AND CONTINUED ADVECTION OF WARM AND MOIST AIR ACROSS THE
THE REGION THROUGH THE PERIOD...WILL LEAVE IN A CHANCE OF SHOWERS
FOR WEDNESDAY NIGHT. TEMPS WEDNESDAY NIGHT WILL NOT FALL MUCH IF AT
ALL WITH A STIFF SOUTHERLY FLOW.

IF WEDNESDAY FEATURES NEAR-RECORD WARMTH...THURSDAY MAY BREAK
RECORDS ACROSS MUCH OF THE REGION AS 850MB TEMPS SURGE TO AN
ASTOUNDING +12C TO +14C AS GULF OF MEXICO AIR IS DRAWN NORTHWARDS
AHEAD OF A LOW PRESSURE SYSTEM LIFTING FROM THE WESTERN GREAT LAKES
TO JAMES BAY...A SCENARIO WE HAVE SEEN MULTIPLE TIMES THIS WINTER
ALREADY. A STRONG WIND FIELD ALOFT WITH A 850MB JET EXCEEDING 55KTS
WILL CREATE THE POTENTIAL FOR STRONG SOUTHERLY WINDS WEDNESDAY NIGHT
INTO THURSDAY. THE COMBINATION OF EXTREME WARM ADVECTION AND
SOUTHERLY DOWNSLOPING COULD EASILY PUSH TEMPERATURES IN THE 60S
ACROSS THE FORECAST AREA UNLESS THE COLD FRONT ARRIVES EARLY
THURSDAY. IT IS ALSO WORTH NOTING THAT RECORD HIGH LOWS WILL LIKELY
BE SET THURSDAY MORNING OWING TO ABOVE FACTORS WITH TEMPERATURES
REMAINING STEADY WITH LOWS ONLY IN THE MID 50S.

IN ADDITION TO THE WARM AND WINDY CONDITIONS...IT WILL LIKELY
BE WET AS WELL AS THE LOW PASSES TO OUR NORTHWEST AND SHOVES A
WEAKENING COOL FRONT ACROSS THE AREA. IT IS WORTH NOTING THAT THE
BETTER UPPER LEVEL SUPPORT AND THUS HEAVIER RAINFALL WILL LIKELY BE
FOUND OVER CANADA. SHOWERS WILL GRADUALLY TAPER OFF THURSDAY NIGHT
BEHIND THE COOL FRONT WHILE TEMPERATURES FALL BACK INTO THE LOWER
40S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
EVEN WITH THE PASSAGE OF A COOL FRONT THURSDAY... WE WILL CONTINUE
TO SEE MILD TEMPERATURES PERSIST THROUGH THE WEEKEND. FLOW ACROSS
THE LOWER GREAT LAKES WILL FLATTEN OUT AND BECOME MORE ZONAL ALOFT
WITH A BAROCLINIC ZONE LAYING ROUGHLY ACROSS THE GREAT LAKES. WITH
THE UPPER LEVEL JET REMAINING TO OUR NORTH...KEEPING ANY COLD AIR
LOCKED UP OVER CANADA...THE REGION WILL REMAIN UNDER THE INFLUENCE
OF MILD AIR FROM OUR SOUTH. HIGH PRESSURE WILL RESULT IN A DRY
CHRISTMAS DAY...THOUGH LINGERING UPPER LEVEL MOISTURE WILL LIKELY
YIELD FILTERED SUNSHINE AT BEST.

THE NEXT SHOT AT PRECIPITATION WILL BE ON SATURDAY AS UPSTREAM FLOW
AMPLIFIES ONCE AGAIN AND A WAVE MOVING ALONG THE AFOREMENTIONED
BAROCLINIC ZONE BRINGS A SOLID CHANCE OF SHOWERS TO THE LOWER GREAT
LAKES. THE BOUNDARY THEN RETREATS TOP THE SOUTH IN THE WAKE OF THE
WAVE ON SUNDAY...LEADING TO A DRY AND SLIGHTLY COOLER END OT THE
WEEKEND. BY COOLER...IT WILL BE SLIGHTLY COOLER AS HIGHS WILL REMAIN
A SOLID 10 DEGREES ABOVE AVERAGE...IN THE LOWER 40S. ANY COOLDOWN
WILL BE SHORT-LIVED AS WELL AS MODELS ARE IN DECENT AGREEMENT ON
PRODUCING ANOTHER SYSTEM SIMILAR TO THURSDAY`S SYSTEM EARLY NEXT
WEEK...LIKELY LEADING TO ANOTHER ROUND OF POTENTIAL RECORD WARMTH.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
EXPECT MAINLY MVFR CONDITIONS THROUGH 09Z. AFTER THIS STEADY RAIN
WILL MOVE IN AND ADD MOISTURE TO AN ALREADY MOIST ENVIRONMENT
WHICH WILL LOWER CIGS AND VSBY TUESDAY MORNING. LINGERING SNOWPACK
NEAR JHW AND CLIMATOLOGY WILL LIKELY LEAD TO LIFR CIGS AND
FOG. THE LOWEST CONDITIONS ELSEWHERE WILL IMMEDIATELY PRECEDE THE
WIND SHIFT...WITH IMPROVING CONDITIONS WHEN SOUTHWEST WINDS
INCREASE IN THE AFTERNOON AND HELP MIX THE BOUNDARY LAYER.

RAIN WILL END FROM W-E TUESDAY AFTERNOON WITH GRADUALLY IMPROVING
CONDITIONS IN MOST LOCATIONS. MVFR/IFR CONDITIONS WILL PROBABLY
LINGER AT JHW/ART INTO TUESDAY EVENING...WITH CLOUDS LIKELY TO
SCATTER AND/OR LIFT AT BUF/IAG/ROC DUE TO THE STRONGER WINDS.

OUTLOOK...
TUESDAY NIGHT...VFR/MVFR. A CHANCE OF SHOWERS.
WEDNESDAY AND THURSDAY...VFR/MVFR WITH RAIN SHOWERS LIKELY.
FRIDAY...VFR. SATURDAY...VFR EARLY LEADING TO MVFR IN SHOWERS.

&&

.MARINE...
WINDS HAVE DIMINISHED LATE THIS EVENING WITH NO HEADLINES ON THE
WATERS. SOUTHWESTERLY WINDS WILL PICK UP ON LAKE ERIE BEHIND A
WEAK SURFACE LOW TUESDAY AFTERNOON...WITH A BRIEF PERIOD OF NEAR-
SCA CONDITIONS.

AS THE NEXT STORM MOVES ACROSS THE UPPER MISSISSIPPI VALLEY AND
UPPER GREAT LAKES ON WEDNESDAY...WINDS WILL BACK TO THE SOUTHEAST
AND FRESHEN. THIS WILL DIRECT THE HIGHEST WAVES INTO CANADIAN
WATERS...BUT WIND SPEEDS IN EXCESS OF 20 KNOTS COULD LEAD TO
ANOTHER ROUND OF SMALL CRAFT ADVISORIES LATER WEDNESDAY INTO
WEDNESDAY NIGHT.

&&

.CLIMATE...
ALTHOUGH BUFFALO HAS GOTTEN ITS FIRST MEASURABLE SNOW...THIS
WINTER CONTINUES TO BE OFF TO AN EXTRAORDINARILY WARM START.

SPEAKING OF WHICH...YET ANOTHER ROUND OF UNSEASONABLE WARMTH IS
EXPECTED THIS WEEK...AS ANOTHER VERY WARM AIRMASS WILL BRING NEAR
RECORD TO POTENTIALLY RECORD-BREAKING HIGHS BOTH WEDNESDAY AND
THURSDAY (CHRISTMAS EVE). HERE ARE THE CURRENT RECORDS FOR
DECEMBER 23RD AND 24TH...

WEDNESDAY...

CITY.........RECORD HIGH (F)....RECORD WARM LOW (F).....

BUFFALO......59 / 1957...........46 / 1941
ROCHESTER....60 / 1957...........43 / 2006
WATERTOWN....58 / 1990...........42 / 2006

CHRISTMAS EVE...

BUFFALO......59 / 1964...........46 / 1979
ROCHESTER....58 / 1982...........47 / 2014
WATERTOWN....59 / 2014...........49 / 2014

WHEN CONSIDERING THE FORECAST THROUGH THE END OF THE MONTH...
DECEMBER 2015 ALSO STANDS A GOOD CHANCE TO BECOME THE WARMEST
DECEMBER ON RECORD IN WESTERN NEW YORK. CURRENT TRENDS SUGGEST
THAT THE MONTHLY AVERAGE TEMPERATURE MAY WELL TOP 40 DEGREES...
WHICH PUTS THE FOLLOWING RECORDS IN SERIOUS JEOPARDY...

WARMEST MEAN TEMPERATURE RECORDS FOR DECEMBER...

CITY        TEMP YEAR
BUFFALO.....37.6 (1923)
ROCHESTER...39.0 (2006)

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...RSH/WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...SMITH/WOOD
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/RSH/WCH
CLIMATE...THOMAS/JJR




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1233 AM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 1233 AM CST TUE DEC 22 2015

NO SIGNIFICANT CHANGES THIS UPDATE FOR THE OVERNIGHT HOURS. THE
SMALL AREA OF DENSE FOG IN THE SOUTH CENTRAL HAS SEEN IMPROVING
VISIBILITIES...LIKELY DUE TO THE HIGHER CLOUDS AND INCREASING WINDS
ASSOCIATED WITH THE APPROACHING SYSTEM FROM THE SOUTHWEST. ISSUED A
SPECIAL WEATHER STATEMENT TO ADDRESS A SMALL AREA OF DENSE FOG IN
THE NORTH CENTRAL NEAR RUGBY/TURTLE MOUNTAINS - ON THE WESTERN EDGE
OF THE LOW STRATUS CLOUDS. THIS AREA SHOULD SEE IMPROVING
VISIBILITIES AS THE HIGH CLOUDS AND INCREASING WINDS REACH THAT AREA
IN THE NEXT COUPLE OF HOURS.

STILL EXPECT SNOW TO DEVELOP QUICKLY JUST BEFORE OR AROUND DAYBREAK
IN THE SOUTHWEST AND SOUTH CENTRAL...EXPANDING QUICKLY NORTH AND
EAST DURING THE MORNING. THE WINTER WEATHER ADVISORY FOR THE NORTH
CENTRAL MAY NEED TO BE EXPANDED WESTWARD AND SOUTHWESTWARD BY A
COUNTY OR SO...BUT REMAINING IN THE NORTH CENTRAL.

UPDATE ISSUED AT 951 PM CST MON DEC 21 2015

NO SIGNIFICANT UPDATES FOR THE LATE EVENING FORECAST. ISSUED A SPS
FOR FOG ALONG THE WESTERN EDGE OF STRATUS ACROSS SOUTH CENTRAL
NORTH DAKOTA. THIS IS MAINLY ALONG THE MISSOURI RIVER FROM THE
SOUTH DAKOTA BORDER TO LAKE SAKAKAWEA. SINCE THE ISSUANCE SOME OF
THE ASOS/AWOS OBSERVATIONS HAVE IMPROVED A LITTLE AS WARM
ADVECTION AND CLOUDS CONTINUE TO INCREASE FROM WEST TO EAST. WILL
CONTINUE TO MONITOR BUT FOR NOW WILL CONTINUE WITH AN SPS AND NOT
ISSUE A DENSE FOG ADVISORY.

TEMPERATURES CONTINUE TO BE AN ISSUE WITH SOME CLEAR SPOTS...BUT
AS STRATUS SPREADS NORTH AND MID-HIGH CLOUDS INCREASE FROM THE
WEST...WE SHOULD SEE TEMPERATURES STEADY...AND MAYBE RISE A BIT.

AS FAR AS SNOWFALL...HAVE DELAYED THE ARRIVAL OF PRECIPITATION BY
A COUPLE HOURS. LATEST ITERATIONS OF THE MESOSCALE MODELS ARE
ACTUALLY PRETTY SIMILAR TO THE PREVIOUS FORECAST...WITH THE SLIGHT
DELAY IN ONSET. NO SIGNIFICANT CHANGES TO THE OVERALL SNOW
FORECAST AS MODELS ARE JUST ROLLING IN...BUT SEE NOTHING AT THIS
TIME INDICATING A SIGNIFICANT CHANGE FROM OUR CURRENT ADVISORY.

UPDATE ISSUED AT 645 PM CST MON DEC 21 2015

MAIN FORECAST PROBLEM FOR THIS EVENING WILL ONCE AGAIN BE
TEMPERATURES AND CLOUDS/FOG.

CURRENTLY...MAINLY CLEAR SKIES ACROSS WESTERN NORTH DAKOTA.
WIDESPREAD STRATUS OVER THE SOUTH CENTRAL FROM AROUND BISMARCK AND
FORT YATES EAST TO THE JAMES RIVER VALLEY...EXCEPT FOR A HOLE THAT
INCLUDES THE KJMS TAF. STRATUS HAS LIFTED ACROSS MOST OF THE NORTH
CENTRAL BUT A FEW PATCHES REMAIN AROUND THE TURTLE MOUNTAINS.
THINK THESE AREAS ACROSS CENTRAL NORTH DAKOTA WILL LIKELY FILL IN
THIS EVENING. ACROSS THE WEST SKIES MAY REMAIN CLEAR UNTIL HIGHER
CLOUDS ASSOCIATED WITH THE NEXT SYSTEM APPROACH BY MID TO LATE
EVENING. THIS WOULD ALLOW TEMPERATURES TO FALL A LITTLE MORE THAN
ORIGINALLY FORECAST. WILL ADJUST SKY BASED ON LATEST SATELLITE
ANALYSIS AND EXPECTATION FROM MESOSCALE MODELS THAT CENTRAL ND
WILL LIKELY CLOUD UP AGAIN WITH STRATUS DURING THE EVENING. WILL
NEED TO LOWER TEMPERATURES A BIT IN THE FAR EAST WHERE
TEMPERATURES ARE ALREADY NEAR FORECAST LOWS...BUT WITH STRATUS IN
PLACE MANY AREAS...WON`T LET THEM DROP TOO MUCH. WILL LIKELY LOWER
TEMPERATURES A LITTLE IN THE WEST AS EVEN THOUGH WARM ADVECTION
AND CLOUDS WILL INCREASE LATER...SHOULD BE A FEW HOURS WITH CLEAR
SKIES AND LIGHT WINDS BEFORE THIS BEGINS IN EARNEST.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

FOG TONIGHT AND ACCUMULATING SNOW TUESDAY HIGHLIGHT THE SHORT TERM
FORECAST.

THE 15-19 UTC HRRR ITERATIONS AND THE 12 UTC NAM NEST ONCE AGAIN
TONIGHT DEPICT FOG DEVELOPMENT WITHIN THEIR RESPECTIVE VISIBILITY
FIELDS. THESE FORECASTS HAVE PERFORMED WELL THE PAST WEEK IN
SIGNALING FOG...AND WILL FOLLOW THEIR SOLUTIONS WHICH SUGGEST FOG
GENERALLY ALONG AND EAST OF HIGHWAY 83 TONIGHT INTO EARLY TUESDAY
MORNING BEFORE THE SNOWFALL. A DENSE FOG ADVISORY MAY BE
POSSIBLE.

FOR TUESDAY...THE 12 UTC AND INCOMING 18 UTC DETERMINISTIC AND
ENSEMBLE SUITES ARE IN AGREEMENT ON A WAVE EJECTING NORTHEAST OUT
OF WYOMING...DEEPENING AND POTENTIALLY CLOSING OFF AS IT
PROPAGATES ACROSS NORTH DAKOTA. STRONG FRONTOGENETIC FORCING AND
VERTICAL MOTION IN THE DENDRITIC GROWTH LAYER ARE EXPECTED ALONG
AND NORTH OF THE 700 MB LOW TRACK FROM SOUTHWEST THROUGH NORTHEAST
NORTH DAKOTA TO SUPPORT MESOSCALE BANDING OF SNOW. THE GREATEST
SNOWFALL AMOUNTS OF 3 TO 5 INCHES ARE FORECAST ACROSS THE FAR
NORTH CENTRAL AND TURTLE MOUNTAINS WHERE SNOWFALL DURATION WILL BE
THE LONGEST IN ASSOCIATION WITH THE DEVELOPING TROWAL. THUS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. FOR NOW...THE
LACK OF STRONG ELEVATED INSTABILITY IS EXPECTED TO KEEP SNOWFALL
AMOUNTS BELOW WARNING LEVELS. HOWEVER...THIS WILL HAVE TO BE
CLOSELY MONITORED IN THE MODEL SOLUTIONS OVER THE NEXT 12 HOURS.
ELSEWHERE...WIDESPREAD ONE TO THREE INCH SNOWFALL AMOUNTS ARE
EXPECTED.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CST MON DEC 21 2015

SURFACE LOW AND ASSOCIATED MID/UPPER LEVEL TROUGH WILL EXIT THE
TURTLE MOUNTAINS AND SHIFT INTO SOUTHERN ONTARIO BY 12Z WEDNESDAY.
SNOW WILL GRADUALLY DIMINISH AND END TUESDAY NIGHT WITH A COLD
POCKET/THERMAL TROUGH LINGERING THROUGH WEDNESDAY. THIS WILL RESULT
IN PLENTY OF CLOUDS AND POSSIBLE FLURRIES WEDNESDAY. ANOTHER WEAK
SHORTWAVE IS EXPECTED THURSDAY AFTERNOON/EVENING...BUT ANY
PRECIPITATION THREAT IS VERY MINIMAL. A SPLIT FLOW DEVELOPS FOR
THE REST OF THE EXTENDED PERIOD AS AN UPPER TROUGH/LOW IS CARVED
OUT IN THE SOUTHWEST. NORTH DAKOTA FALLS UNDER A SOUTHWEST FLOW
ALOFT CHRISTMAS DAY/FRIDAY...WITH A DEFORMATION ZONE EVOLVING
ACROSS SOUTHERN NORTH DAKOTA FRIDAY NIGHT INTO SATURDAY MORNING.
CHRISTMAS DAY REMAINS DRY WITH MOISTURE ADVECTION INCREASING
FRIDAY EVENING FAR SOUTH. THIS IS IN RESPONSE TO AN INITIAL
MID/UPPER LEVEL LOW EJECTING FROM THE SOUTHWEST UPPER TROUGH WILL
SLIDE ACROSS SOUTH DAKOTA DURING THE ABOVE TIME. WILL CONTINUE TO
WATCH THE TRACK BUT AS OF NOW SOME LIGHT SNOW IS EXPECTED SOUTH OF
I-94 DURING THIS TIME. THIS SHORTWAVE DEPARTS SATURDAY NIGHT WITH
DRY WEATHER UNTIL AT LEAST MONDAY. HIGHS WILL REMAINING IN THE 20S
WED/THU...THEN COLDER AIR WILL BE DRAWN INTO THE APPROACHING
SOUTHWEST SYSTEM WITH WINDS BECOMING NORTH TO NORTHEAST FRI/SAT.
AS THE SYSTEM DEPARTS AND WINDS BECOME SOUTHWEST...HIGHS WILL ONCE
AGAIN REBOUND INTO THE 20S SUNDAY AND MONDAY. OVERNIGHT LOWS WILL
BE COLDEST FRIDAY MORNING THROUGH SUNDAY MORNING WITH LOWS 5 BELOW
ZERO NORTH TO 5 ABOVE ZERO SOUTH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1233 AM CST TUE DEC 22 2015

AREAS OF MVFR-IFR STRATUS EXPECTED IN CENTRAL NORTH DAKOTA EARLY
THIS MORNING AT KBIS/KJMS. VFR CONDITIONS WEST AT KISN/KMOT/KDIK
EARLY...THEN INCREASING CLOUDS WITH AN APPROACHING SMALL BUT POTENT
LOW PRESSURE SYSTEM. THIS SYSTEM WILL BRING MVFR-IFR CEILINGS AND
VISIBILITIES IN SNOW AND FOG FROM MAINLY KDIK AND KBIS AROUND 12Z TO
KMOT AND KJMS BEGINNING AROUND 15Z. THE SYSTEM WILL EXIT SLOWLY TO
THE NORTHEAST TUESDAY EVENING...BUT THE POTENTIAL FOR LOW STRATUS
AND FOG WILL REMAIN AT TAF SITES.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR NDZ005-012-013-022-023-025.

&&

$$

UPDATE...JV
SHORT TERM...AYD
LONG TERM...KS
AVIATION...JV




AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 1131 PM EST MON DEC 21 2015

.SYNOPSIS...
IT WILL BE UNSETTLED AND UNSEASONABLY MILD WEATHER WILL CONTINUE
THIS WEEK WITH TEMPERATURES ON TRACK TO PEAK NEAR OR BEYOND RECORD
LEVELS ON CHRISTMAS EVE.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LITTLE MORE THAN ISOLATED LIGHT SHOWERS OR SPRINKLES AS OF 9 PM.
PRECIP IS SURGING NE AHEAD OF THE NEXT SHORTWAVE IN THE
FLOW...MOVING INTO WEST VIRGINIA NOW...WITH THE HRRR TIMING THE
RAIN INTO MY SWRN ZONES SHORTLY AFTER MIDNIGHT. HAVE RAISED POPS
CLOSER TO SREF VALUES GIVEN THE LARGE SHIELD OF RAIN UPSTREAM.

TEMPS GOT STUCK IN THE LOWER/MID 40S OVER MUCH OF CWA TODAY...BUT
THEY ALSO WON`T FALL OFF MUCH OVERNIGHT AS LOW LEVEL SW FLOW
CONTINUES TO PUSH WARMER AIR INTO THE REGION.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
PACIFIC SHORTWAVE #2 AND ITS WEAK SURFACE LOW QUICKLY LIFTS
NORTHEAST THROUGH THE LOWER GREAT LAKES INTO THE ST. LAWRENCE
VALLEY/NORTHERN NEW ENGLAND BY 00Z WED. A.M. RAIN SHOULD COME TO
AN END FAIRLY ABRUPTLY EARLY TUESDAY AFTERNOON AS RIDGING BUILDS
IN BEHIND THE DEPARTING SYSTEM. THEREFORE TRENDED HIGH PRECIP
PROBS IN THE MORNING STEADILY DOWNWARD WITH A MAINLY DRY PERIOD
/ALBEIT STILL RATHER CLOUDY/ FROM ROUGHLY 18Z TUESDAY TO 12Z
WEDNESDAY. 24HR RAINFALL AMOUNTS ENDING TUESDAY AFTERNOON SHOULD
AVERAGE BETWEEN 0.25 TO 0.50 INCH IN MOST PLACES WHICH IS RIGHT IN
LINE WITH THE GEFS MEAN. THE SREF MEAN QPF IS A LITTLE WETTER
WHICH IS LIKELY DUE TO THE NAM INFLUENCE BEING TOO VIGOROUS WITH
ITS ASCENT AND MOISTURE FIELDS PER WPC MODEL DIAG.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THERE ARE SEVERAL MAJOR FORECAST QUESTIONS THIS WEEK. THE MOST
ANOMALOUS IS THE POSSIBLE RECORD TEMPERATURES. THE LONG AND MID
RANGE MODELS CONTINUE TO BE IN FAIR AGREEMENT WITH THE OVERALL
PATTERN AND BY THURSDAY THE SREF ENSEMBLES HAVE +14C TEMPS AT
850HPA. SO RECORD TEMPERATURES ACROSS CENTRAL PA ARE STILL ON
TRACK FOR CHRISTMAS EVE WITH FCST HIGHS OF 60-70F DEGREES WITH
MILD TEMPERATURES ALL WEEK.

THE NEXT QUESTION IS THE TIMING OF SUCCESSIVE SHORT WAVES MOVING
THROUGH THE UPPER LEVEL PATTERN. AS AN UPPER LEVEL TROUGH
MOVES INTO THE GREAT LAKE REGION...A MID LEVEL TROUGH WILL
MOVE THROUGH THE OHIO VALLEY. THIS SHOULD BRING STRONG WARM AND MOIST
SOUTHWESTERLY FLOW INTO THE REGION LATE WEDNESDAY...EARLY
THURSDAY.  THE LATEST GEFS HAS PWATS OF +3 TO +4 STANDARD
ANOMALIES. SO THAT EVENT SHOULD HAVE THE HEAVIEST
PRECIPITATION. HAVE INCREASED QPF/S UPWARDS...AS WELL AS ADJUSTED
POPS ACCORDINGLY. THAT WARM FRONT WILL BE FOLLOWED BY A WEAKENING
COLD FRONT CHRISTMAS EVE. THE FROPA WILL KNOCK TEMPERATURES BACK
SOME FOR CHRISTMAS DAY BUT IT SHOULD REMAIN ABOVE NORMAL INTO THE
WEEKEND.

THE MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS NOW TRENDING
TOWARD THE IDEA OF A POTENTIAL SIGNIFICANT RAINFALL AXIS SETTING
UP ALONG THE OLD COLD FRONT THAT COULD TRANSITION TO A QUASI-
STATIONARY BOUNDARY. THE GFS/ECMWF DIFFER TO SOME EXTENT ON THE
EVOLUTION OF THE BOUNDARY BUT BOTH SEEM TO FAVOR A RAINFALL AXIS
FROM ROUGHLY DALLAS TX NEWD THROUGH NEW ENGLAND...SATURDAY NIGHT
INTO SUNDAY. CONFIDENCE IN THE PCPN DETAILS DROPS OFF BY THE END
OF THE PERIOD GIVEN THE MODEL SPREAD AND VARIABILITY IN THE
PLACEMENT OF THE PRECIPITATION- FOCUSING BOUNDARY. HOWEVER THE
BOUNDARY SHOULD DIP SOUTHWARD INTO NEXT WEEK AS THE FLOW BECOMES
MORE ZONAL AS THE LOW MOVES INTO THE CENTRAL UNITED STATES.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
SURFACE LOW PRESSURE WILL MOVE FROM SOUTHERN MICHIGAN TO THE
EASTERN GREAT LAKES BY TUESDAY AFTERNOON...PUSHING ITS ASSOCIATED
WARM FRONT NWD ACROSS PENNSYLVANIA. ACCOMPANYING THIS FRONT WILL
BE A POTENT UPPER LEVEL DISTURBANCE AND A PLUME OF DEEP MOISTURE
WITH ITS ORIGIN OVER THE GULF OF MEXICO. THE MOISTURE WILL BE
FUNNELED INTO PENNSYLVANIA LATER TONIGHT INTO EARLY TUESDAY
AFTERNOON...BRINGING PERIODS OF RAIN AND GENERALLY IFR CIGS AND
VSBYS.

IFR CONDITIONS /IN THE FORM OF LOW CIGS - BLANKETING MUCH OF NWRN
PENN AT 04Z/ WILL SLOWLY SPREAD SOUTH AND EAST LATE TONIGHT
REACHING THE CENTRAL RIDGE AND VALLEY REGION BEFORE DAYBREAK. ONLY
A FEW BRIEF SHOWERS ARE EXPECTED EARLY TONIGHT.

THE SUSQ VALLEY AIRFIELDS WILL STAY VFR UNTIL THE 08-10Z TIMEFRAME
FOLLOWED BY A DROP INTO MVFR CIGS...WITH VFR TO MVFR VSBYS IN
PERIODS OF RAIN THAT WILL PERSIST INTO AT LEAST EARLY TUESDAY
AFTERNOON.

STIFF SSW-SWRLY LOW LEVEL JET WILL CONTINUE THE LLWS OVER WESTERN
TERMINALS THROUGH THE OVERNIGHT.

MORE NUMEROUS SHOWERS OR EVEN SOME PERIODS OF STEADIER RAIN WILL
ARRIVE FROM THE SW LATER TONIGHT ACROSS ALL OF CENTRAL AND NRN
PENN AND CONTINUE INTO THE EARLY AFTERNOON TUESDAY.

FAIRLY ABRUPT IMPROVEMENT SHOULD OCCUR LATE TUE AFTERNOON AS
RIDGE QUICKLY WORKS IN BEHIND THE DEPARTING SYSTEM. HOWEVER...THE
LLVL WSW FLOW COULD KEEP LOW CIGS AT KJST AND KBFD FOR SEVERAL
HOURS AFTER THE PASSAGE OF THE WEAK SFC CFRONT.

AFTER SOME IMPROVEMENT AND MAINLY DRY CONDITIONS FOR LATER TUESDAY
INTO WEDNESDAY MORNING...MORE UNSETTLED WEATHER WITH OCCASIONAL
SHOWERS WILL RETURN FOR WEDNESDAY AFTERNOON AND PERSIST INTO
THURSDAY... WITH BREEZY CONDITIONS DEVELOPING.


OUTLOOK...
TUE...WIDESPREAD RESTRICTIONS IN RAIN. SOME IMPROVEMENT LATER IN
THE AFTERNOON.

WED...CIG RESTRICTIONS AND ANOTHER ROUND OF RAIN LIKELY. BREEZY.

THU...CIG RESTRICTIONS POSS WEST. IMPROVING CONDITIONS ELSEWHERE.
CONTINUED BREEZY.

CHRISTMAS...NO SIG WX EXPECTED.

SAT...RESTRICTIONS POSS SOUTH.

&&

.CLIMATE...
DECEMBER 2015 CONTINUES TO BE UNSEASONABLY MILD. ANOTHER ROUND OF
WELL ABOVE AVERAGE TEMPERATURES THIS WEEK WILL BRING POTENTIALLY
RECORD SETTING TEMPERATURES FOR WEDNESDAY AND THURSDAY /CHRISTMAS
EVE/. HERE ARE THE CURRENT RECORDS FOR WEDNESDAY THE 23RD AND
THURSDAY THE 24TH...

RECORD HIGH TEMPERATURES...
SITEWED RECORDTHU RECORDNORMAL
HARRISBURG65F (1990)62F (1990)39F
WILLIAMSPORT63F (1990)56F (1931)36F
ALTOONA62F (1957)62F (1965)36F
BRADFORD56F (1990)55F (1965)31F
STATE COLLEGE*65F (1933)63F (1933)36F
*STATE COLLEGE RECORD IS FROM 7AM TO 7AM COOP SITE...
I.E. WEDNESDAY/S RECORD IS ACTUALLY 7AM WED - 7AM THU

RECORD HIGH LOW TEMPERATURES...
SITETHU RECORDFRI RECORDNORMAL
HARRISBURG49F (1931)45F (1891)25F
WILLIAMSPORT45F (2014)43F (1895)22F
ALTOONA41F (1972)42F (1987)21F
BRADFORD44F (1965)42F (1982)16F
STATE COLLEGE*45F (1931)46F (1893)22F
*STATE COLLEGE RECORD IS FROM 7AM TO 7AM COOP SITE...
I.E. THURSDAY/S RECORD IS ACTUALLY 7AM WED - 7AM THU

WITH THE CONTINUED VERY MILD TEMPERATURES...DECEMBER 2015 IS ON
TRACK TO BE THE WARMEST DECEMBER ON RECORD AT ALL SITES.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...RXR
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/RXR
CLIMATE...




AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 1057 PM CST MON DEC 21 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 239 PM CST MON DEC 21 2015

A VERY WEAK WAVE LIFTING THROUGH THE AREA THIS AFTERNOON. NOTHING
MORE THAN FLURRIES EXPECTED AS A FAIRLY SIGNIFICANT DRY LAYER EXISTS
FROM ABOUT 900MB TO 700MB. OTHERWISE A STRONG WAVE WILL MOVE INTO
THE AREA TONIGHT...BUT THE MAIN EFFECTS WILL BE TO THE NORTH OF THE
CWA. WHILE A ROUGE TENTH OR TWO TENTHS OF AN INCH OF SNOWFALL NOT
IMPOSSIBLE MAINLY ALONG AND NORTH OF INTERSTATE 90...JUST FLURRIES OR
PATCHY LIGHT SNOW ARE EXPECTED. CLOUD COVER SHOULD GRADUALLY
DECREASE THROUGH THE DAY TOMORROW...BUT WE WILL LIKELY REMAIN FAIRLY
ENTRENCHED THROUGH TOMORROW MORNING.

AS FOR TEMPERATURES...AS THE WAVE MOVES THROUGH TO THE NORTH LOW
LEVEL SOUTHERLY FLOW WILL INCREASE THROUGH THE NIGHT...WHICH SHOULD
ALLOW FOR RISING TEMPERATURES IN MANY LOCATIONS. LOWS MILD...TEENS
TO LOWER 20S...WILL RISE TO DAYTIME HIGHS FROM THE UPPER 30S TO MID
40S ON TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 239 PM CST MON DEC 21 2015

ONE PASSING WAVE WILL BRING A CHANCE OF LIGHT SNOW/RAIN TO THE
SOUTHEAST CORNER OF THE AREA TUESDAY NIGHT AND WEDNESDAY MORNING AS
COOLER AIR TRIES TO FILTER IN. THIS WAVE WILL EXIT WEDNESDAY
AFTERNOON AND ANOTHER WAVE WILL APPROACH FROM THE WEST WEDNESDAY
NIGHT. WHILE THE MODELS...ESPECIALLY THE EC...MAKE THIS WAVE A
LITTLE STRONGER THAN THE FIRST ONE...IT STILL LOOKS WEAK AND
PRECIPITATION AMOUNTS WILL BE PRETTY LIGHT IF IN FACT IT DEVELOPS.
WILL KEEP POPS IN THE LOW MENTION RANGE AS WITH THE FIRST WAVE AND
KEEP THE THREAT TIME AT LATE WEDNESDAY NIGHT AND THURSDAY MORNING.
THE POTENTIAL AFFECTED AREA WILL BE THE SOUTHERN EDGE OF THE
FORECAST AREA.

SKIES WILL VARY FROM PARTLY TO MOSTLY CLOUDY TUESDAY NIGHT THROUGH
MOST OF THURSDAY. TEMPERATURES WILL BE A LITTLE COOLER THAN TUESDAY
BUT STILL ABOVE NORMAL. WINDS WILL BE LIGHT TO MODERATE...WITH THE
STRONGEST BREEZE IN THE COOL FLOW WEDNESDAY DAYTIME...POSSIBLY
SURGING TO REACH THE LOWER END OF THE BREEZY CATEGORY.

THE COMPLICATED UPPER LOW DIGGING INTO THE SOUTHWESTERN USA AND
WAVES SPINNING NORTHEAST FROM IT WILL BEING A COUPLE THREATS OF
PRECIPITATION...MAINLY SNOW...TO THE AREA DURING THE FRIDAY THROUGH
MONDAY PERIOD. RIGHT NOW TIMING LOOKS RIGHT FOR THE FIRST SYSTEM
FRIDAY INTO SATURDAY WITH ONE OF THOSE ADVANCE WAVES...AND THE OTHER
THREAT MONDAY AS THE MAIN UPPER LOW COMES UP. MODELS ARE SHOWING
BETTER AGREEMENT ON THE MONDAY SYSTEM THAN THEY HAVE THE LAST
SEVERAL DAYS WITH THE FRIDAY SYSTEM. STILL...TOO EARLY TO GET
EXCITED WITH A LOT OF VARIABLES UNCERTAIN. THE APPROACH OF THIS
DEVELOPING SYSTEM WILL DRAW A LITTLE MORE COOL AIR INTO THE NORTHERN
PLAINS AND GET TEMPERATURES A LITTLE CLOSER TO NORMAL...BUT ARCTIC
AIR HAS NO CHANCE OF APPROACH IN THIS PATTERN

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1044 PM CST MON DEC 21 2015

CERTAINLY NO SHORTAGE OF IFR TO LIFR CONDITIONS ACROSS THE
FORECAST AREA AT THIS TIME. BELIEVE STRONGLY THAT THIS SITUATION
WILL PREVAIL FOR THE NEXT SEVERAL HOURS. HOWEVER LATE TONIGHT...
THE LOW LEVEL WINDS INCLUDING SURFACE WINDS INCREASE DRAMATICALLY
IN ADVANCE OF THE NEXT SHORT WAVE WHICH MOVES ACROSS THE AREA
TUESDAY MORNING. AS THE WINDS INCREASE FROM THE SOUTH AND
SOUTHEAST...IT IS ANTICIPATED THAT THE VISIBILITY WILL IMPROVE
TOWARD TUESDAY MORNING...BUT THE LOW STRATUS WILL LINGER. INCLUDED
THIS SCENARIO IN THE TAF SITES...ESPECIALLY AT KFSD WHERE THICKER
FOG HAS SET IN.

FURTHER OUT...THE NAM HUMIDITY TIME SECTIONS AND SOUNDINGS
CONTINUE TO SHOW A NEVER ENDING REGIME OF LOW CLOUDS THROUGH THE
DAY TUESDAY. THE ONE EXCEPTION IS AT KSUX WHERE IT SHOWS SOME
CLEARING. THE GFS ON THE OTHER HAND VIRTUALLY SHOWS NO LOW CLOUDS
WITH ITS FORECAST WHICH OBVIOUSLY IS NOT LINING UP WITH REALITY.
WHAT LOOKED THE BEST WAS THE LATEST RAP. THE RAP SHOWS CLEARING IN
THE LOW LAYERS LATE TUESDAY MORNING AND EARLY AFTERNOON WHICH
STANDS TO REASON AS YOU DO NOT HAVE TO GO VERY DEEP INTO NEBRASKA
TO FIND NO STRATUS. SO ONCE THE WINDS SHIFT TO THE SOUTH AS
TONIGHT PROGRESSES...ONE WOULD THINK THAT THE FORECAST AREA WILL
GO VFR TOWARD THE MIDDLE OF THE DAY ON TUESDAY.

&&

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

$$

SHORT TERM...08
LONG TERM...
AVIATION...MJ




AREA FORECAST DISCUSSION

NWS NASHVILLE TN

 317 AM CST TUE DEC 22 2015

.DISCUSSION...

...UNUSUAL LATE DECEMBER SEVERE WEATHER OUTBREAK POSSIBLE ON
WEDNESDAY INTO WEDNESDAY NIGHT...

LATEST SURFACE OBSERVATIONS SHOW UNUSUALLY MILD AND HUMID
CONDITIONS ACROSS THE MID STATE WITH TEMPERATURES AND DEWPOINTS
IN THE MID 50S TO LOW 60S. RADAR SHOWS WIDESPREAD SHOWERS AND A
COUPLE OF THUNDERSTORMS CONTINUE OVER MAINLY THE NORTHWEST HALF
OF THE CWA ATTM. LATEST HRRR RUNS INDICATE MOST OF THIS ACTIVITY
WILL SHIFT NORTHEAST OF THE CWA BY 12Z...WITH ONLY ISOLATED
SHOWERS POSSIBLE THE REST OF TODAY MAINLY ACROSS THE SOUTH.
STRONG WAA WILL CONTINUE TO PUMP GULF MOISTURE INTO THE
AREA TODAY...WITH TEMPERATURES RISING WELL INTO THE 60S BY THIS
AFTERNOON. BY THIS EVENING....00Z MODELS PROG A SMALL H5 SHORTWAVE
TO MOVE FROM THE GULF COAST TOWARDS EAST TN...BRINGING THE NEXT
ROUND OF SHOWERS AND STORMS MAINLY TO THE SOUTHEAST HALF OF THE
CWA TUESDAY NIGHT.

SEVERE THUNDERSTORMS ARE BECOMING INCREASINGLY LIKELY ON
WEDNESDAY INTO WEDNESDAY NIGHT AS 00Z GFS/ECMWF NOW IN GOOD
AGREEMENT TAKING A LARGE H5 NEGATIVELY TILTED TROUGH INTO THE
LOWER MISSISSIPPI AND TENNESSEE VALLEYS DURING THE DAY. SOME
MODELS INCLUDING THE 00Z NMMB DEVELOP CONVECTION ACROSS MS/AL
THAT MOVES RAPIDLY ACROSS EASTERN MIDDLE TENNESSEE BY LATE
MORNING...AND SHOULD THIS OCCUR SOME OF THESE STORMS COULD BE
STRONG OR EVEN SEVERE AS EFFECTIVE CAPE INCREASES UP TO 500 J/KG
AND SFC-6KM SHEAR RISES TO 60 KTS BY 18Z. HOWEVER...MAIN SEVERE
THUNDERSTORM POTENTIAL APPEARS TO BE WEDNESDAY AFTERNOON INTO
WEDNESDAY EVENING AS SFC COLD FRONT PUSHES TOWARDS THE MID STATE
FROM THE WEST. SEVERAL MODELS INCLUDING THE 00Z/06Z NAM...00Z
GFS...AND OTHERS ALL SUGGEST CELLULAR CONVECTION...INCLUDING
POTENTIAL SUPERCELLS...WILL DEVELOP ACROSS MS/WEST TN THEN SPREAD
VERY RAPIDLY NORTHEAST AT UP TO 55 KTS ACROSS THE CWA INTO
WEDNESDAY EVENING. SFC TEMPS IN THE 70S WITH DEWPOINTS WELL INTO
THE 60S...CAPES RISING INTO A SEASONABLY HIGH 500-1000 J/KG
RANGE...AND SFC-6KM SHEAR INCREASING TO 70-75KTS BETWEEN 23/18Z
AND 24/06Z ALL SUGGEST LIKELIHOOD FOR SEVERE THUNDERSTORMS DURING
THIS TIMEFRAME. OF NOTABLE CONCERN...SHARPPY 00Z GFS SOUNDINGS
SHOW FAVORABLE CONDITIONS FOR COOL-SEASON TORNADOES WITH A VERY
MOIST BOUNDARY LAYER...SFC-1KM SRH AROUND 400 M2/S2...AND LCLS
BELOW 1000M. SPC HAS ACCORDINGLY BUMPED UP OUR SEVERE RISK INTO
THE ENHANCED CATEGORY FOR WEDNESDAY/WEDNESDAY NIGHT. MAIN NEGATIVE
FACTORS FOR A SEVERE WEATHER OUTBREAK ACROSS OUR CWA ARE THE
HIGHEST INSTABILITY REMAINING TO OUR WEST/SOUTHWEST...UNFAVORABLE
SURFACE LOW PLACEMENT WELL TO OUR NORTH IN THE GREAT
LAKES/CANADA...AND CLIMATOLOGY SHOWING DECEMBER AS THE LEAST
LIKELY MONTH FOR TORNADOES ACROSS MIDDLE TENNESSEE.

AFTER SHOWERS AND STORMS EXIT THE MID STATE EARLY
THURSDAY...APPEARS FORECAST AREA WILL BE MOSTLY DRY DURING THE
DAY WITH TEMPERATURES WARMING WELL INTO THE 70S. THIS DRY PERIOD
WILL BE SHORT LIVED AS WARM FRONT RETURNS NORTHWARD THURSDAY
NIGHT AND ESPECIALLY CHRISTMAS DAY BRINGING YET ANOTHER ROUND OF
WIDESPREAD SHOWERS AND THUNDERSTORMS. VERY WARM AND HUMID
CONDITIONS ARE THEN EXPECTED OVER THE WEEKEND WITH TEMPERATURES IN
THE 70S AND DEWPOINTS IN THE 60S...ALTHOUGH POPS WILL BE LOW WITH
MAINLY JUST ISOLATED SHOWERS ANTICIPATED. GFS/ECMWF CONTINUE TO
STRUGGLE WITH EVOLUTION OF MAIN UPPER TROUGH/CLOSED H5 LOW OVER
THE WESTERN CONUS...WITH ECMWF NEARLY 24 HOURS SLOWER THAN THE GFS
EJECTING SYSTEM EASTWARD. HOWEVER...THIS IS A KNOWN BIAS OF THE
ECMWF...AND LEANED MORE TOWARDS THE GFS WITH HIGHEST POPS ON
MONDAY INTO MONDAY NIGHT AS STRONG COLD FRONT BRINGS ANOTHER ROUND
OF WIDESPREAD SHOWERS AND POTENTIALLY STRONG THUNDERSTORMS TO THE
MID STATE IN THIS VERY UNUSUAL LATE DECEMBER WEATHER PATTERN.

&&

.AVIATION...
06Z TAF DISCUSSION.

MAIN BATCH OF SHOWERS WILL MOVE ACROSS THE PLATEAU (CSV) AREA IN
THE NEXT FEW HOURS...WITH SCT -SHRA TO THE WEST. CIGSS WILL DROP
TO IFR LATE IN THE NIGHT AND AREAS OF BR WILL FORM. CIGS WILL BE
SLOW TO IMPROVE ON TUESDAY...BUT SHOULD CLIMB TO MVFR BY MIDDAY.
WINDS WILL BE MOSTLY SOUTH 7-10KT. A FEW 18KT GUST WILL OCCUR
OVERNIGHT.


&&

.CLIMATE...

AS FAR AS SEVERE WEATHER CLIMATOLOGY GOES...DECEMBER IS THE LEAST
LIKELY MONTH FOR TORNADOES IN MIDDLE TENNESSEE...WITH ONLY 7 ON
RECORD /INCLUDING 1 IN LINCOLN COUNTY/ SINCE THE EARLY 1800S. THE
LAST TORNADO IN MIDDLE TENNESSEE DURING THE MONTH OF DECEMBER
OCCURRED ON DECEMBER 16 2000 WHEN THE AFOREMENTIONED TORNADO HIT
LINCOLN COUNTY. IN THE OHX CWA...THE LAST DECEMBER TORNADO ON
RECORD OCCURRED IN WILLIAMSON COUNTY ON DECEMBER 24 1988.

THE UNUSUALLY WARM WEATHER OVER THE NEXT SEVERAL DAYS WILL LIKELY
SET SOME RECORDS. WILL SEND OUT A PNS LISTING ALL OF THE RECORD
HIGHS AND RECORD WARM MINIMUM TEMPERATURES FOR NASHVILLE AND
CROSSVILLE LATER THIS MORNING.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SHORT TERM/AVIATION........01/BOYD
LONG TERM..................55/SHAMBURGER




AREA FORECAST DISCUSSION

NWS MEMPHIS TN

 1141 PM CST MON DEC 21 2015

.DISCUSSION...

UPDATED FOR 06Z AVIATION DISCUSSION

&&

.PREV DISCUSSION... /ISSUED 906 PM CST MON DEC 21 2015/

UPDATE...

A COLD FRONT IS ON THE DOOR STEPS OF NORTHEAST ARKANSAS AT THIS
TIME. MOST OF THE HEAVIER SHOWER ACTIVITY HAS PUSHED EAST OF THE
CWA. ALTHOUGH A NEW BAND OF SHOWERS HAS DEVELOPED OVER THE LAST
FEW HOURS JUST AHEAD OF THE FRONT. THE HRRR SHOWS THIS BAND
EXPANDING A TAD AS IT PUSHES EASTWARD ACROSS THE MIDSOUTH. WILL
KEEP POPS AS IS FOR THE REMAINDER OF THE NIGHT.

IN ADDITION...SOME CLEARING MAY OCCUR ACROSS NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL BEHIND THE FRONT. A LITTLE WORRIED DENSE
FOG MAY DEVELOP AS WINDS WILL REMAIN LIGHT. DENSE FOG IS ALREADY
BEING REPORTED NEAR CLINTON ARKANSAS. FOR NOW WILL ADD AREAS OF
FOG FOR AREAS ALONG AND WEST OF THE MISSISSIPPI RIVER. UPDATE WILL
BE OUT SHORTLY.

KRM

DISCUSSION... /ISSUED 348 PM CST MON DEC 21 2015/

WE REMAIN IN A VERY ACTIVE PATTERN. EXPECT RAIN ACROSS AT LEAST A
PORTION OF THE MIDSOUTH EVERY DAY THROUGH THE END OF THE WEEKEND.
ABNORMALLY WARM CONDITIONS WILL ALSO CONTINUE. THIS FORECAST
UPDATE WILL FOCUS PRIMARILY ON THE THREAT FOR SEVERE THUNDERSTORMS
LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO CONTINUE BEFORE AND AFTER THEN.

CURRENTLY RAIN IS MOSTLY CONFINED TO NORTH MISSISSIPPI AND A
SMALL AREA OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. EMBEDDED
THUNDERSTORMS HAVE BEEN NOTED...ALTHOUGH NOTHING TO BE CONCERNED
ABOUT. TEMPERATURES ARE IN THE MIDDLE 50S TO LOW 60. A MODERATE
SOUTH WIND IS PUMPING GULF MOISTURE ACROSS THE AREA...SETTING THE
STAGE FOR A POTENTIAL ROUND OF SEVERE WEATHER MIDWEEK.

TOMORROW SHOULD BE WARMER...IN THE LOW 60S TO LOW 70S ACROSS MOST
OF THE REGION...RAIN SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE...MAINLY IN NORTH MISSISSIPPI.

TEMPERATURES WEDNESDAY WILL BE 22-28 DEGREES ABOVE NORMAL...MAINLY
IN THE MIDDLE 70S. DEW POINTS WILL BE AS HIGH AS THE MIDDLE
60S...CREATING AN AIRMASS THAT FEELS MORE LINE SPRING THEN LATE
DECEMBER.

SYNOPTICALLY...OVER THE NEXT 48 HOURS OR SO A VERY BROAD TROUGH
WILL DEEPEN OVER THE WESTERN US...AND SHIFT INTO THE PLAINS. LATE
TUESDAY NIGHT INTO EARLY WEDNESDAY ITS AXIS SHOULD BE OVER
CENTRAL OKLAHOMA...WITH A SLIGHTLY NEGATIVELY TILTED SHORTWAVE
APPROACHING THE MISSISSIPPI RIVER VALLEY. THE STORM PREDICTION
HAS INCLUDED A LARGE PORTION OF THE MIDSOUTH...MAINLY ALONG AND
SOUTH OF THE INTERSTATE 40 CORRIDOR IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. WARM TEMPERATURES AND DEW POINTS IN THE 60S WILL
CREATE VERY UNSTABLE ATMOSPHERIC CONDITIONS...ESPECIALLY FOR
DECEMBER. THE NAM GENERATES CAPE VALUES IN EXCESS OF 1000J/KG AS
FAR NORTH AS MEMPHIS...WITH THE GFS NOT MUCH LOWER IN VALUES...BUT
NOT AS FAR NORTH SPATIALLY. I TYPICALLY DO NOT PUT MUCH FAITH IN
CONVECTIVE PARAMETERS MORE THAN 36 HOURS IN THE FUTURE...BUT
VALUES THAT HIGH ARE HARD TO IGNORE. SHEAR PROFILES ARE ALSO
FAIRLY IMPRESSIVE...AND NOT OVERLY INTENSE WHERE MANY TIMES THEY
ARE A DETRIMENT TO SUSTAINED UPDRAFTS. STRONGLY CURVED HODOGRAPHS
FEATURE 0-3KT HELICITY UP TO 300 M^2/S^2 IN NORTH MISSISSIPPI.
1000-500MB LAPSE RATES ARE BETWEEN 5.8C/KM AND 6.2 C/KM. ORGANIZED
SEVERE STORM ARE POSSIBLE...INCLUDING SUPERCELLS. LARGE
HAIL...LOCALLY DAMAGING WIND GUSTS AND TORNADOES ALL APPEAR
POSSIBLE. HOLIDAY TRAVELERS SHOULD PAY PARTICULARLY CLOSE
ATTENTION TO THIS FORECAST.

THE SEVERE THREAT SHOULD DIMINISH OVERNIGHT AS THE SHORTWAVE
TROUGH SHIFTS ACROSS THE MISSISSIPPI RIVER VALLEY. HOWEVER...THE
LARGER SCALE TROUGH WILL REMAIN ANCHORED OVER THE CENTRAL PLAINS.
AS A RESULT WE MAY SEE A BREAK IN WIDESPREAD RAIN AND
THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY. UNFORTUNATELY
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO RETURN CHRISTMAS EVE
NIGHT. HOPEFULLY SANTA CAN GET ALL THE GIFTS DELIVERED ACROSS THE
MIDSOUTH BEFORE THE RAIN BEGINS.

LATE IN THE WORK WEEK...A DEEPENING TROUGH OVER THE SOUTHWEST WILL
RESULT IN STRONG SOUTHWEST FLOW ACROSS THE MIDSOUTH. THIS
TYPICALLY MEANS WET CONDITIONS ACROSS OUR AREA. THIS TIME DOESN`T
LOOK LIKE AN EXCEPTION. WILL CARRY HIGH CHANCE TO EVEN LIKELY POPS
FRIDAY THROUGH THE WEEKEND. TEMPERATURES WILL REMAIN SEASONABLY
WARM.

30

&&

.AVIATION...

06Z TAF CYCLE

IFR/LIFR CONDS ACROSS THE AREA ATTM. SCT SHRAS ARE OCCURRING
MAINLY EAST OF THE MS RIVER AND ACROSS THE MO BOOTHEEL. THIS
ACTIVITY WILL MOVE EAST OF THE AREA OVER THE NEXT FEW HOURS.
EXPECT CONDS TO DETERIORATE TO LIFR AFTER MIDNIGHT AREAWIDE IN
LOW CLOUDS AND FOG. FOG SHOULD BE MORE DENSE AT KJBR SINCE THEY
WILL PROBABLY LOOSE THE CLOUD DECK LATER TONIGHT. STARTING TO SEE
THIS WITH VSBYS LESS THAN 1 MILE JUST TO WEST OF KJBR. CONDS WILL
GRADUALLY IMPROVE TUESDAY MORNING. KJBR SHOULD BREAK OUT AND
BECOME VFR. KMEM IS ON THE FENCE SO WENT WITH A SCT015 TEMPO
THERE FOR NOW. KEPT AN MVFR DECK GOING THROUGH THE DAY AT KMKL
WITH IFR CONDS CONTINUING AT KTUP. FRONT WILL WASH OUT ACROSS THE
AREA AND LOW CLOUDS WILL PUSH BACK NORTH TUE EVENING. RAIN LIKELY
AT KTUP IN THE EVENING.

WINDS WILL CONTINUE TO VEER TO THE WEST/NW AND BECOME LIGHT/VRBL
AT KJBR/KMEM/KMKL AS THE FRONT MOVES INTO THE AREA AND WASHES
OUT. LIGHT SOUTHERLY WINDS WILL REDEVELOP TUESDAY AFTN. FRONT
NEVER REALLY MAKES IT TO KTUP AND WINDS REMAIN S/SSW THERE.

SJM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$




AREA FORECAST DISCUSSION...UPDATED

NWS AUSTIN/SAN ANTONIO TX

 1203 AM CST TUE DEC 22 2015

.UPDATE...HAVE ISSUED A DENSE FOG ADVISORY FOR THE COASTAL PLAINS
INTO BEXAR COUNTY AND FOR LOCATIONS ALONG AND SOUTH OF THE EDWARDS
PLATEAU AS VISIBILITIES DOWN AT OR BELOW ONE QUARTER OF A MILE
WILL BE LIKELY. VISIBILITIES HAVE ALREADY BEGUN TO DECREASE LATE
THIS EVENING AND THIS TREND IS EXPECTED TO CONTINUE GIVEN THE RAP
NEAR SURFACE SATURATION INDICATIONS. DEWPOINT DEPRESSIONS ARE NEAR
ZERO ALREADY AND THE RAP OUTPUT SUGGESTS THESE CONDITIONS THAT
WILL PROMOTE AREAS OF DENSE FOG WILL PERSIST THROUGH THE OVERNIGHT
AND MORNING HOURS. WE WILL NEED TO MONITOR HOW LOW THE DEPRESSIONS
GET ACROSS THE NORTHERN PORTIONS OF I-35 THROUGH DAWN AND SEE IF
AN EXPANSION OF THE ADVISORY IS NEEDED.

THE AREAS OF DENSE FOG SHOULD DECREASE BY 9 TO 10 AM BUT LOW
CLOUDS WILL LINGER ACROSS THE PLAINS AND THE RIO GRANDE TO EDWARDS
PLATEAU INTO THE EARLY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 1032 PM CST MON DEC 21 2015/

AVIATION...
TEMPERATURE/DEWPOINT DEPRESSIONS ARE NEARING ZERO IN SPOTS ALONG
AND OFF THE ESCARPMENT RESULTING IN BR/FG WITH LCL VSBYS 1/4 MILE
OR LESS ALONG AND SE OF A KDRT TO K5C1 TO KTPL LINE. EXPECT THIS
TO CONTINUE OVERNIGHT INTO TUESDAY MORNING AND HAVE MENTIONED
IFR/MVFR BR AT ALL TAF SITES WITH TEMPO LIFR/VLIFR IN FG AT THE
I-35 SITES. THERE IS SOME UNCERTAINTY ON DURATION OF FG AT KAUS
AND KSAT DUE TO DRAINAGE FLOW OFF THE HILLS. BR/FG LIFTS BY LATE
MORNING TO BE REPLACED BY STRATUS WITH MVFR CIGS IN THE AFTERNOON
AS LOWER LEVEL MOISTURE INCREASES. CIGS LOWER TUESDAY NIGHT TO IFR
AS AIRMASS COOLS. ISOLD/SCT SHRA/TSRA ARE POSSIBLE EAST OF KPEZ TO
KHDO TO KERV TO KAQO LINE TUESDAY AND TUESDAY NIGHT. FOR NOW...
WILL NOT MENTION IN THE TAFS...ALTHOUGH...MONITOR RADAR/MODEL
TRENDS FOR POSSIBLE LATER MENTION. VARIABLE WINDS OF 5 KTS OR LESS
TONIGHT BECOME S TO SE 5 TO 15 KTS ON TUESDAY.

PREV DISCUSSION... /ISSUED 945 PM CST MON DEC 21 2015/

UPDATE...
WE ARE BEGINNING TO SEE FOG FORM ACROSS THE REGION. SOME PLACES
HAVE VISIBILITY DOWN TO A QUARTER OF A MILE. HAVE UPDATED THE
FORECAST TO INCLUDE PATCHY DENSE FOG ALONG AND SOUTH OF
I-35/HWY90. AT THIS TIME WE THINK LOW VISIBILITY WILL NOT BE
WIDESPREAD...SO WE WILL HOLD OFF ISSUING ADVISORY.
HOWEVER...CONDITIONS MAY DETERIORATE OVER THE NEXT FEW HOURS.
STILL A CHANCE DRIER AIR WILL MOVE FARTHER SOUTH AND EAST.

PREV DISCUSSION... /ISSUED 616 PM CST MON DEC 21 2015/

AVIATION...
A WEAK COLD FRONT WILL SAG SOUTHEAST FROM THE HILL COUNTRY ACROSS
THE ESCARPMENT THIS EVENING AND STALL OUT INLAND FROM THE COASTAL
PLAINS. EVEN THOUGH DRIER AIR FILTERS IN BEHIND THE FRONT...
EXPECT MOIST AIR AT THE SURFACE TO RETURN BY MORNING AND MENTIONED
IFR/MVFR VSBYS IN BR IN THE TAFS. SOUTHERLY WINDS STRENGTHEN ON
TUESDAY AHEAD OF ANOTHER FRONT AND UPPER LEVEL TROUGH. LOWER LEVEL
MOISTURE INCREASES WITH STRATUS AND MVFR CIGS DEVELOPING DURING
THE DAY MAINLY AT THE I-35 TAF SITES. ISOLD/SCT SHRA/TSRA ARE
POSSIBLE ALONG/EAST OF I-35 TUESDAY INTO TUESDAY NIGHT. FOR
NOW...WILL NOT MENTION IN THE TAFS AND MONITOR RADAR/MODEL TRENDS
FOR POSSIBLE LATER MENTION. VARIABLE WINDS 5 KTS OR LESS TONIGHT
BECOME S TO SE 5 TO 15 KTS ON TUESDAY.

PREV DISCUSSION... /ISSUED 343 PM CST MON DEC 21 2015/

SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
A COLD FRONT IS CURRENTLY LOCATED ALONG A LLANO TO KERRVILLE TO
NEAR ROCKSPRINGS LINE LATE THIS AFTERNOON. COOLING BEHIND THE
BOUNDARY HAS BEEN OFFSET WITH DOWNSLOPING WINDS. THERE HAS BEEN
SOME DRYING BEHIND THE FRONT WITH DEW POINTS IN THE 40S BEHIND THE
FRONT COMPARED TO 50S AND 60S AHEAD OF THE FRONT. THIS COLD FRONT
IS FORECAST TO CONTINUE A SLOW EASTWARD MOVEMENT TONIGHT...BUT
SHOULD SLOW/STALL IN THE COASTAL PLAINS TOWARD SUNRISE TUESDAY. WE
COULD SEE SOME PATCHY FOG FOR AREAS EAST OF THE COLD FRONT...AND
WE/LL MENTION THIS IN THE FORECAST FOR TONIGHT.

ON TUESDAY...SOUTHERLY SLOW QUICKLY RETURNS TO THE REGION...
ALLOWING AN INCREASE IN MOISTURE ACROSS ALL AREAS. MEANWHILE...
WE/LL SEE AN INCREASING SOUTHWEST FLOW ALOFT OVER TEXAS. THE SHORT
RANGE MODELS SHOW ONE SHORTWAVE TO OUR SOUTH WITH ANOTHER
SHORTWAVE WELL TO OUR NORTHWEST. WITH AN ACTIVE SOUTHWEST FLOW
ALOFT AND DAYTIME HEATING...WE EXPECT ISOLATED TO SCATTERED
AFTERNOON CONVECTION FOR AREAS ALONG AND EAST OF THE I-35
CORRIDOR. CAN/T COMPLETELY RULE OUT A STRONG TO POSSIBLY SEVERE
STORM OR TWO...BUT IT CONTINUES TO LOOK LIKE THE BETTER LIFT WILL
REMAIN NORTH OF OUR REGION. THE MAIN CONCERN WITH ANY STORMS THAT
MANAGE TO DEVELOP WILL BE GUSTY WINDS AND HAIL.

LONG TERM (WEDNESDAY THROUGH MONDAY)...
A PACIFIC COLD FRONT IS SET TO MOVE ACROSS SOUTH CENTRAL TEXAS ON
WEDNESDAY...BRINGING DRIER AIR AND SOME GUSTY NORTHWEST WINDS TO
ALL AREAS. TEMPERATURES WILL STILL REMAIN ABOVE NORMAL ON
WEDNESDAY AS DOWNSLOPE WINDS AND DRY AIR ALLOW ANOTHER DAY OF
HIGHS IN THE 70S. ON THURSDAY...THE MODELS SHOW A MORE NORTHERN
STREAM COLD FRONT MOVING INTO WESTERN AND NORTHERN TEXAS DURING
THE MORNING HOURS. THIS BOUNDARY MAY BE STRONG ENOUGH TO REACH THE
WESTERN HILL COUNTRY...BUT TEMPERATURES ARE STILL EXPECTED TO
REMAIN ABOVE NORMAL. SOUTHERLY FLOW IN THE LOW-LEVELS QUICKLY
RETURNS THURSDAY NIGHT...BRINGING AN INCREASE IN MOISTURE AND
CLOUD COVER TO ALL AREAS. SOME LIGHT SHOWERS ARE POSSIBLE ALONG
AND EAST OF THE I-35 CORRIDOR...WITH RAINFALL AMOUNTS EXPECTED TO
REMAIN RATHER LOW.

THE FORECAST FOR LATE THIS WEEK INTO EARLY NEXT WEEK CONTINUES TO
REMAIN HIGHLY UNCERTAIN. MODEL RUN TO RUN CONSISTENCY HAS BEEN
POOR TO SAY THE LEAST. THE MODELS SHOW AN UPPER TROUGH DROPPING
SOUTH INTO THE GREAT BASIN REGION ON FRIDAY...THEN DEVELOP THE
TROUGH INTO A CLOSED LOW OVER THE DESERT SOUTHWEST OR NORTHERN
MEXICO LATE SATURDAY INTO EARLY SUNDAY. THE LOW IS THEN FORECAST
TO GRADUALLY MOVE EASTWARD INTO THE SOUTHERN U.S. PLAINS EARLY
NEXT WEEK...WITH THE TRACK OF THE LOW REMAINING HIGHLY UNCERTAIN.
FOR NOW...WE/LL BEGIN TO SHOW AN INCREASE IN RAIN CHANCES ACROSS
ALL AREAS...EXCEPT THE RIO GRANDE PLAINS ON FRIDAY. RAIN CHANCES
CONTINUE TO INCREASE ON SATURDAY WITH AN ACTIVE SOUTHWEST FLOW
ALOFT AND WELL ABOVE NORMAL MOISTURE IN PLACE. A STRONG COLD FRONT
IS THEN SET TO MOVE IN EITHER LATE SATURDAY OR EARLY SUNDAY...
BRINGING COOLER TEMPERATURES AND A DOWNWARD TREND IN PRECIPITATION
CHANCES. AS MENTIONED ABOVE...THE FORECAST LATE THIS WEEK INTO
EARLY NEXT WEEK REMAINS UNCERTAIN. STANDARD DEVIATIONS IN THE 4 TO
8 RANGE OBSERVED IN THE GFS MOS ENSEMBLE NUMBERS INDICATE THE
AMOUNT OF UNCERTAINTY IN THIS FORECAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              74  50  76  61  78 /  10   0  20  30  10
AUSTIN BERGSTROM INTL AIRPORT  73  46  76  62  78 /  10   0  20  30  10
NEW BRAUNFELS MUNI AIRPORT     75  50  77  61  80 /  10   0  20  30  10
BURNET MUNI AIRPORT            72  46  73  56  74 /  10   0  10  30  10
DEL RIO INTL AIRPORT           73  46  75  51  78 /   0   0   0   0   0
GEORGETOWN MUNI AIRPORT        75  46  74  60  76 /  10   0  20  30  10
HONDO MUNI AIRPORT             72  47  76  56  78 /   0   0  10  10  -
SAN MARCOS MUNI AIRPORT        73  49  75  61  77 /  10   0  20  30  10
LA GRANGE - FAYETTE REGIONAL   76  53  77  65  78 /  20  -   20  40  20
SAN ANTONIO INTL AIRPORT       74  51  76  62  79 /  10   0  10  20  10
STINSON MUNI AIRPORT           75  52  77  62  79 /  10   0  10  20  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR THE FOLLOWING
COUNTIES: ATASCOSA...BASTROP...BEXAR...CALDWELL...DE WITT...
DIMMIT...FAYETTE...FRIO...GONZALES...GUADALUPE...KARNES...KINNEY...
LAVACA...LEE...MAVERICK...MEDINA...UVALDE...WILSON...ZAVALA.

&&

$$

MESOSCALE/AVIATION...TB3
SYNOPTIC/GRIDS...ALLEN





AREA FORECAST DISCUSSION

NWS MOUNT HOLLY NJ

 922 AM EST TUE DEC 22 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST BUT DISSIPATE BEFORE
REACHING THE MID ATLANTIC TODAY. A WARM FRONT WILL DEVELOP TO THE
SOUTH OF THE REGION TODAY, LIFTING NORTHWARD THROUGH THE AREA LATE
WEDNESDAY. A COLD FRONT WILL CROSS THE REGION THURSDAY NIGHT. HIGH
PRESSURE BRIEFLY RETURNS FOR CHRISTMAS DAY. A WARM FRONT WILL LIFT
NORTHWARD THROUGH THE REGION OVER THE WEEKEND, FOLLOWED BY A COLD
FRONT EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...


A SWLY LOW-LEVEL JET AHEAD OF THE SHORTWAVE TROUGH IS RESPONSIBLE
FOR A BAND OF OVERRUNNING PRECIP THAT STRETCHES FROM THE GULF COAST
TO CENTRAL PA. EXPECT SHOWERS TO BE LIGHT AND SCATTERED FROM I-95
WEST BEFORE 5 AM. THE STEADY RAIN WILL THEN OVERSPREAD THE AREA FROM
WEST TO EAST BETWEEN ABOUT 5 AM AND 9 AM. GUIDANCE, INCLUDING THE
HRRR, CONTINUE TO SHOW THE STEADIEST RAIN MOVING THRU NE PA AND ALSO
THE COASTAL PLAIN.

THE STEADY RAIN IS EXPECTED TO TAPER OFF FROM SW TO NE BETWEEN ABOUT
NOON AND 3 PM. ANY LINGERING SHOWERS OVER NJ/NE PA ARE EXPECTED TO
EXIT BEFORE SUNSET. BREAKS IN THE CLOUDS ARE ALSO EXPECTED TO
DEVELOP LATE IN THE DAY.

UNDERCUT MAV/MET GUIDANCE BY A DEGREE OR TWO FOR THIS AFTERNOON DUE
TO THE RAIN AND CLOUD COVER. ANY CLEARING LOOKS TO OCCUR AFTER PEAK
HEATING HOURS. IT`LL STILL BE VERY WARM FOR LATE DECEMBER STANDARDS
WITH HIGHS IN THE MU50S IN NE PA/NW NJ AND LM60S ELSEWHERE.

LATEST RADAR IMAGERY SHOWED MOST OF THE PRECIP IN NJ AND DE ATTM.
W OF THE DE RIVER IT HAS ALL BUT ENDED. THERE CUD BE SOME
ADDITIONAL DEVELOPMENT ACCORDING TO THE HRRR IN ALG AND SE OF THE
I-95 CORRIDOR LATER THIS MRNG/ELY THIS AFTN, BUT PRECIP SHUD END
LATER THIS AFTN. HOWEVER, FOR THE NEXT FEW HOURS, AT LEAST, MOST
OF NRN AND WRN AREAS SHOULD BE RELATIVELY RAIN FREE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE PRESSURE GRADIENT IS FORECAST TO WEAKEN OVER THE AREA THIS
EVENING. THIS WILL ALLOW THE WINDS TO BECOME LIGHT AFTER SUNSET.
WITH A WET GROUND, BREAKS IN THE CLOUDS LIKELY TO DEVELOP AND THE
LIGHT WINDS THIS EVENING, THE AREA WILL BE PRIMED FOR RADIATIONAL
FOG TO DEVELOP. THERE IS A POTENTIAL FOR DENSE FOG IF SKIES CAN
CLEAR OUT FOR MOST OF THE EVENING. WILL MENTION THE CONDITIONAL
THREAT IN THE HWO. HOWEVER, DID NOT ADD THE DENSE QUALIFIER IN THE
WX GRIDS ATTM DUE TO SOME UNCERTAINTY IN HOW THE SETUP EVOLVES.

MIN TEMPS ARE IN LOW/MID 50S IN THE URBAN AND COASTAL LOCALES; 40S
IN THE RURAL AREAS.

HIGHER CLOUDS ARE EXPECTED TO MOVE BACK INTO THE AREA LATE TONIGHT
AS THE NEXT MID-LEVEL SHORTWAVE TROUGH AND WARM FRONT APPROACH FROM
THE SOUTH. SHOWERS MAY START TO OVERSPREAD THE DELMARVA AND FAR SRN
NJ ZONES EARLY IN THE MORNING.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WEDNESDAY...A WARM FRONT DEVELOPING TO OUR SOUTH WILL GRADUALLY PUSH
NORTHWARD THROUGH THE DAY, PUSHING THROUGH OUR ARE WEDNESDAY NIGHT.
WITH A STRONG SOUTH/SOUTHWEST FLOW ALOFT, WE WILL CONTINUE TO HAVE
AN INCREDIBLE AMOUNT OF WARM, MOIST AIR RUSHING INTO OUR AREA. RAIN
WILL PUSH INTO THE REGION DURING THE MORNING AND THEN CONTINUE
THROUGH THE DAY. TEMPERATURES WILL RESPOND IN KIND AND ARE EXPECTED
TO SOAR INTO THE 60S THROUGH MUCH OF THE AREA. AREAS ACROSS THE
SOUTH MAY SEE TEMPERATURES RISE INTO THE LOWER 70S. AREAS ACROSS THE
NORTH MAY TAKE LONGER TO WARM DUE TO THE INCREASED DISTANCE FROM THE
WARM FRONT BUT ARE EXPECTED TO REACH INTO THE UPPER 50S TO LOWER
60S.

THURSDAY...THE WARM FRONT PUSHES NORTH OF THE AREA EARLY. STRONG
WARM AIR ADVECTION WILL CONTINUE ON THURSDAY AND UNSEASONABLY WARM
TEMPERATURES WILL RISE TO RECORD BREAKING LEVELS. HIGHS INTO THE 70S
ARE EXPECTED. A COLD FRONT, MORE LIKE A COOL FRONT, WILL CROSS THE
AREA THURSDAY NIGHT. THERE ARE EXPECTED TO BE BREAKS IN THE
PRECIPITATION COVERAGE THROUGH THE DAY ON THURSDAY BUT OVERALL EXPECT
SHOWERS TO END FROM NORTHWEST TO SOUTHEAST LATE THURSDAY. MODEL
SOUNDINGS DO SHOW SOME ELEVATED INSTABILITY WHICH MEANS THERE COULD
BE SOME ISOLATED RUMBLES OF THUNDER AROUND THE AREA. HOWEVER,
CONFIDENCE IS TOO LOW TO INCLUDE THUNDER IN THE FORECAST AT THIS
TIME.

FRIDAY/CHRISTMAS DAY...THIS MAY BE THE NICEST DAY OF THE EXTENDED
PERIOD AS WE SEE HIGH PRESSURE BRIEFLY BUILD INTO THE AREA. COOLER
THAN FRIDAY BUT WITH NO STRONG COLD AIR ADVECTION TAKING PLACE
BEHIND THE DEPARTING COLD FRONT, WE DON`T EXPECT TEMPERATURES TO
COOL OFF THAT MUCH. IT WILL CERTAINLY FEEL COLDER THAN THURSDAY AS
HIGHS WILL BE AROUND 10 TO 15 DEGREES COOLER ACROSS THE REGION.
HOWEVER, IT WILL STILL BE UNSEASONABLY WARM WITH HIGHS INTO THE 60S
THROUGH MUCH OF THE FORECAST AREA.

SATURDAY THROUGH MONDAY...ANOTHER WARM FRONT DEVELOPS TO OUR SOUTH
AND ONCE AGAIN THIS FRONT WILL TRACK NORTHWARD AND INTO OUR AREA. A
COLD FRONT WILL THEN CROSS THE REGION FROM THE WEST EARLY IN THE
WEEK. THERE ARE CONSIDERABLE TIMING DIFFERENCES IN THE MODELS AS TO
WHEN EITHER OF THE FRONTS ARRIVE AND THIS WILL DIRECTLY IMPACT HOW
MUCH PRECIPITATION WE MIGHT SEE ACROSS OUR REGION INTO EARLY NEXT
WEEK. WITH TOO MUCH UNCERTAINTY, HAVE NOT MADE MANY CHANGES TO THE
CURRENT FORECAST.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

EXCEPT FOR KABE AND KRDG, TAF SITES REMAIN VFR FOR CIGS, AND MVFR
FOR VSBYS. RAIN HAS ENDED ACRS MOST OF PA. HAVE MADE MORE
OPTIMISTIC TAFS FOR THE NEXT FEW HOURS FOR I-95 TAF SITES AND
POINTS E.

STILL SOME UNCERTAINTY AS TO WHAT HAPPENS LATER THIS AFTN. THERE
ARE IFR CIGS S AND W, SO WILL THOSE MOVE INTO THE REGION OR NOT.
ALL GUID STILL INDICATES YES, AND WHAT IS HAPPENING AT RDG AND ABE
WOULD SUGGEST YES. HOWEVER, THE GUID OVERPLAYED ITS HAND THIS
MRNG, SO CONFIDENCE IS LOW.

THE RAIN WILL QUICKLY END FROM SW TO NE DURING THE EARLY
AFTERNOON BUT IFR OR LOW MVFR CIGS MAY LINGER LATER INTO THE
AFTERNOON. THERE IS STILL A MODERATE AMOUNT OF UNCERTAINTY
REGARDING HOW QUICKLY THE TAF SITES WILL IMPROVE TO MVFR AND THEN
VFR. WENT WITH A CONSENSUS BETWEEN THE LAMP AND NAM MOS GUIDANCE
FOR THE 06Z TAFS, CALLING FOR THE LOW CLOUDS TO SCATTER OUT
BETWEEN 21Z AND 00Z.

A S-SWLY WIND MAINLY AOB 10 KT THIS MORNING. SHORTLY AFTER RAIN ENDS
THIS AFTERNOON, MIXING WILL DEEPEN, WINDS WILL VEER SLIGHTLY FROM
THE W-SW AND GUSTS TO 20 KT ARE POSSIBLE.

VFR TO START THE EVENING. GOOD SETUP FOR FOG TONIGHT ASSUMING
CLEARING OCCURS AS ADVERTISED BY GUIDANCE. EXPECT THE FOG TO DEVELOP
BEFORE MIDNIGHT AT THE MORE RURAL TERMINALS WITH A WET GROUND IN
PLACE. IFR/LIFR POSSIBLE OVERNIGHT. HIGHER CLOUD COVER AND LIGHT
RAIN MAY START TO OVERSPREAD ILG-MIV-ACY BEFORE 12Z WED. EVEN IF THE
FOG DISSIPATES AND VSBYS IMPROVE, CIGS SHOULD REMAIN LOW
(IFR/VLIFR).

OUTLOOK...

WEDNESDAY...MVFR/IFR CONDITIONS EXPECTED WITH RAIN OVERSPREADING THE
REGION. SOUTHEAST WINDS BECOME MORE SOUTHERLY THROUGH THE DAY. WINDS
AROUND 15 TO 20 KNOTS THROUGH THE AFTERNOON.

WEDNESDAY NIGHT...IFR CONDITIONS EXPECTED TO IMPROVE TO MVFR ACROSS
THE TERMINALS AS A WARM FRONT LIFTS NORTH OF THE REGION AND RAIN
BEGINS TO RAPER OFF. STRONG SOUTHWESTERLY WINDS UP TO 20 KNOTS.

THURSDAY...MVFR CONDITIONS EXPECTED TO CONTINUE. POSSIBLE
IMPROVEMENT TO VFR DURING THE AFTERNOON IN ADVANCE OF A COLD
FRONT. RAIN RETURNS THURSDAY AFTERNOON. SOUTHWEST WINDS 10 TO 15
KNOTS WITH HIGHER GUSTS POSSIBLE.

THURSDAY NIGHT...MVFR CONDITIONS EXPECTED IN RAIN WITH IMPROVEMENT
TO VFR BEHIND A COLD FRONTAL PASSAGE. GUSTY SOUTHWEST WINDS WILL
BECOME WEST BEHIND THE FRONT.

FRIDAY AND FRIDAY NIGHT...VFR CONDITIONS EXPECTED WITH WEST WINDS
AROUND 5 TO 10 KNOTS. A CHANCE FOR SOME RAIN LATE WITH MVFR
CONDITIONS POSSIBLE.

SATURDAY....MVFR CONDITION EXPECTED IN RAIN AS A WARM FRONT
MOVES INTO THE AREA.

&&

.MARINE...
SW WINDS 10-15 KT AND SEAS 3-5 FT IN OUR ATLANTIC WATERS (1-2 FT
IN THE DE BAY) THIS MORNING. WINDS ARE EXPECTED TO INCREASE TO
15-20 KT THIS AFTN BUT THERE IS NOT MUCH POTENTIAL FOR STRONGER
GUSTS IN THIS STABLE SETUP (WARM AIR ATOP THE COOLER WATERS).
CANNOT RULE OUT ISOLATED 25 KT GUSTS THIS AFTERNOON AT OUR
OFFSHORE BUOYS. A SCA WAS ISSUED FOR THIS AFTERNOON AND EVENING
FOR OUR ATLANTIC COASTAL ZONES WITH SEAS EXPECTED TO BUILD TO
AROUND 5 FT. NO HEADLINES FOR THE DE BAY.

WINDS BECOME LIGHT TONIGHT. SEAS SHOULD SUBSIDE LATE THIS EVENING
AND OVERNIGHT.

OUTLOOK...

WEDNESDAY AND THURSDAY...SMALL CRAFT ADVISORY CONDITIONS EXPECTED.
INCREASING STRONG SOUTHERLY FLOW WILL BUILD SEAS TO 5 TO 7 FEET.
STRONG SOUTHERLY WINDS AROUND 20 TO 30 KNOTS EXPECTED.

THURSDAY NIGHT THROUGH FRIDAY MORNING...WINDS WILL DROP OFF FAIRLY
QUICK BEHIND A COLD FRONTAL PASSAGE THURSDAY NIGHT. SEAS WILL TAKE A
LITTLE BIT LONGER TO SUBSIDE AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED THROUGH FRIDAY MORNING.

FRIDAY MORNING THROUGH SATURDAY...SUB-ADVISORY CONDITIONS EXPECTED.
WEST WINDS WILL BECOME NORTH OVERNIGHT AND THEN NORTHEAST ON
SATURDAY. SEAS AROUND 2 TO 4 FEET.

&&

.CLIMATE...
DAILY RECORD HIGHS ARE POSSIBLE THIS WEDNESDAY, DECEMBER 23. THE
CALENDAR DAY HIGHS ON WEDNESDAY MAY OCCUR CLOSE TO MIDNIGHT WHEN
TEMPERATURES ARE EXPECTED TO RISE AFTER A WARM FRONT MOVES
THROUGH. THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE WARM
FRONT BUT THE EARLIER THE WARM FRONT MAKES IT HERE, THE MORE
LIKELY THESE DAILY RECORDS WILL BE BROKEN.

DAILY RECORD HIGHS ARE EXPECTED THURSDAY, DECEMBER 24TH. CURRENTLY,
RECORD HIGHS ARE FORECAST FOR ALL 8 CLIMATE SITES.

THE FOLLOWING TABLE LISTS THE DAILY RECORD HIGHS FOR DECEMBER 23 AND
24TH THAT ARE IN JEOPARDY AT OUR EIGHT CLIMATE SITES.

        DECEMBER 23                   DECEMBER 24
SITE    RECORD HIGH  YEAR(S) SET      RECORD HIGH  YEAR(S) SET
        -----------  -----------      -----------  -----------
ACY     65           1990             65           1982
PHL     66           1990             64           1990, 2014
ILG     66           1990             65           2014
ABE     64           1990             62           1990
TTN     70           1891             63           1990, 2014
GED     68           1949, 2013       69           2014
RDG     63           1990, 2007       63           1990
MPO     58           1990             62           1990


WE MAY APPROACH ALL-TIME MONTHLY RECORD HIGHS (I.E., THE WARMEST DAY
IN DECEMBER) AS WELL. CURRENT FORECAST HIGHS ON THE 24TH ARE WITHIN
1-3 DEGREES OF THESE MONTHLY RECORDS AT SEVERAL LOCATIONS.

        MONTHLY RECORD
SITE    HIGHS FOR DECEMBER      DATE(S) SET
        ------------------      -----------
PHL     73                      12/4/1998, 12/7/1998
ACY     77                      12/7/1998
ILG     75                      12/4/1998
ABE     72                      12/29/1984, 12/4/1998, 12/1/2006
TTN     76                      12/7/1998
GED     77                      12/1/1991
RDG     77                      12/29/1984
MPO     67                      12/13/2015


DECEMBER 2015 IS ON PACE TO SET THE ALL-TIME MONTHLY RECORD FOR
THE WARMEST DECEMBER AT PHILADELPHIA. THE AVERAGE TEMPERATURE FROM
DECEMBER 1-21ST AT PHL AIRPORT WAS 49.4F (10.6F ABOVE NORMAL)
WHICH IS THE WARMEST ON RECORD THROUGH THE FIRST 21 DAYS OF THE
MONTH. THE PREVIOUS WARMEST WAS 48.6F IN 2001.

MEAN TEMPERATURES THE LAST 10 DAYS OF THE MONTH (DECEMBER 22-31)
WOULD HAVE TO AVERAGE 34.5F (OR 0.2F BELOW NORMAL) TO TIE DECEMBER
1923 FOR THE WARMEST DECEMBER ON RECORD AT PHILADELPHIA (44.6F).
BASED ON OUR CURRENT FORECAST, WHICH HAS AN AVERAGE TEMPERATURE OF
57F (20-25F ABOVE NORMAL) FROM DECEMBER 22-28 AND CPC`S 6-10 DAY
OUTLOOK OF CONTINUED ABOVE NORMAL TEMPS, WE`LL SMASH THE PREVIOUS
RECORD BY MORE THAN 5F!

TO TRY TO PUT THE ABOVE INTO PERSPECTIVE...
THERE IS ONLY ONE OTHER OCCURRENCE IN THE PHILADELPHIA RECORD
BOOKS WHERE THE WARMEST MONTHLY MEAN TEMPERATURE WAS MORE THAN ONE
DEGREE HIGHER THAN THE SECOND WARMEST... THE MONTHLY MEAN
TEMPERATURE OF 46.2F IN JANUARY 1932 IS 2.9F ABOVE THE SECOND
WARMEST JANUARY ON RECORD (1950). BASED ON THE WHAT`S HAPPENED SO
FAR THIS MONTH AND OUR 7-DAY FORECAST, THE MEAN MONTHLY
TEMPERATURE PROJECTED THRU THE 28TH WOULD BE 51.2F. COMPARED TO
OTHER MONTHS (AND ASSUMING THE MONTHLY MEAN DOESN`T CHANGE
SIGNIFICANTLY OVER THE LAST THREE DAYS OF THE MONTH), THIS WOULD
RANK DECEMBER 2015 IN THE TOP THREE WARMEST MARCHES ON RECORD, IN
THE TOP 8 WARMEST NOVEMBERS ON RECORD AND ONLY A FEW DEGREES BELOW
THE MONTHLY NORMAL TEMPERATURE FOR APRIL!

OFFICIAL MONTHLY TEMPERATURE RECORDS FOR PHILADELPHIA DATE BACK TO
1872.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ450>455.

&&

$$
SYNOPSIS...MEOLA
NEAR TERM...KLEIN/NIERENBERG
SHORT TERM...KLEIN
LONG TERM...MEOLA
AVIATION...KLEIN/NIERENBERG/MEOLA
MARINE...KLEIN/MEOLA
CLIMATE...




AREA FORECAST DISCUSSION

NWS MELBOURNE FL

 930 AM EST TUE DEC 22 2015

.DISCUSSION...

...MUCH ABOVE NORMAL TEMPERATURES THE REST OF THE WEEK...
...MODERATE TO HIGH RISK OF RIP CURRENTS THRU THE UPCOMING HOLIDAY
WEEKEND...

TODAY/TONIGHT...LARGE HIGH PRESSURE RIDGE EXTENDING FROM NEAR BERMUDA
TO CENTRAL FLORIDA WILL PROVIDE A SOUTHEAST/SOUTH LOW LEVEL WIND
FLOW.  THIS WILL ELEVATE MOISTURE LEVELS WITH FORECAST PRECIPITABLE
WATER VALUES RISING TO NEAR 1.5 INCHES BY MAX HEATING TIME. MORNING
SOUNDINGS STILL SHOW SOME DRY AND RATHER WARM MID LEVEL AIR BUT
SLIGHT COOLING OF THIS LAYER IS INDICATED BY FORECAST SOUNDINGS.

THE MAIN FORECAST PROBLEM REVOLVES AROUND POPS...AND VARIOUS MODELS
HAVE ALL DIFFERENT TYPES OF SOLUTIONS.  THINK THAT THUNDERSTORM
COMPLEX VICINITY MISSISSIPPI DELTA/APALACHICOLA WILL BUILD A LITTLE
SOUTHWARD INTO THE GULF OF MEXICO AND PUMP A HIGH CLOUD CANOPY INTO
OUR NORTHERN SECTIONS.  SO EVEN THOUGH SOME DIVERGENCE ALOFT IS
INDICATED THERE THIS AFTERNOON...HEATING WILL BE LIMITED AND INHIBIT
DEEP UPDRAFTS.  SOUTHERN SECTIONS SHOULD HAVE THE GREATEST DIRECT
INSOLATION.  THE NAM AND HRRR MODELS SHOW SOME CONVECTION WORKING UP
OUT OF SOUTH FLORIDA LATE IN THE DAY AND INTO EVENING...WITH THE
HRRR INDICATING A SLIGHT LIGHTNING RISK OVER OUR SOUTH/CENTRAL
INTERIOR.  OVERALL THOUGH...DO NOT SEE ENOUGH TO ADD LIGHTNING TO
THE FORECAST YET.  OUR 30 PERCENT SHOWER CHANCES EXCEPT 40 IN THE
FAR SOUTH LOOK OKAY TOO...THOUGH THESE CHANCES COULD BLEED OVER INTO
THE EARLY NIGHTTIME PERIOD.

OTHERWISE...NO CHANGES TO WARM/HUMID FORECAST FOR TODAY.  SEVERAL
RECORD WARM LOWS MAY OCCUR TONIGHT.

&&

.AVIATION...SUNSHINE A BIT MUTED BY CIRRUS BUT EXPECT HEATING TO
GENERATE CLOUD FIELD WITH DECENT COVERAGE AGAIN. LOCAL MVFR
POSSIBLE BUT GENERALLY CEILINGS AT OR ABOVE FL035.  CHANCE OF
AFTERNOON SHOWERS BUT NOT CERTAIN ENOUGH WITH LOCATION/TIMING TO
INCLUDE ANY TEMPO GROUPS.  MOS GUIDANCE GENERATES A LOT OF STRATUS
AND FOG AGAIN TONIGHT FOR THE INTERIOR TERMINALS AND KDAB...BUT WITH
CONSIDERABLE CLOUD COVER...THIS LOOKS RATHER SKETCHY AGAIN.

&&

.MARINE...TODAY/TONIGHT...BUOYS 41009 AND 41010 SHOWING WINDS IN THE
EXERCISE CAUTION RANGE.  MARINE MOS SHOWS A SLIGHT DECREASE IN WINDS
THIS AFTERNOON AND THEN AN INCREASE THIS EVENING AND OVERNIGHT.
WITH SEAS AROUND 6 FEET...PLAN TO KEEP THE CURRENT EXERCISE CAUTION
STATEMENT FOR THE OFFSHORE ZONES.

&&

.CLIMATE...DAYTONA BEACH HAD A MORNING LOW OF 71 DEGREES THIS
MORNING AND TEMPERATURES ARE NOT FORECAST TO GO BELOW THAT THIS
EVENING...SO THEY WILL LIKELY HAVE A RECORD WARM LOW FOR TODAY.
VERO BEACH WILL COME CLOSE TO REACHING THEIR RECORD HIGH FOR
TODAY. HIGHER CHANCES FOR WARM TEMPERATURE RECORDS WED-CHRISTMAS DAY.

RECORD HIGHS TUE THROUGH FRI...

      DEC-22     DEC-23     DEC-24     DEC-25
DAB  85(2013)   85(2013)   84(1981)   82(1988)
MCO  86(2013)   86(2013)   85(2014)   85(1924)
MLB  84(2013)   86(2013)   85(2014)   87(1981)
VRB  84(2013)   84(2013)   87(2014)   85(1997)

RECORD WARM LOWS TUE THROUGH FRI...

      DEC-22     DEC-23     DEC-24     DEC-25
DAB  70(2006)   68(2013)   67(1997)   69(1997)
MCO  68(1911)   68(1911)   67(2006)   69(1997)
MLB  73(2006)   68(2006)   71(1987)   72(1997)
VRB  74(2006)   69(2013)   72(2014)   71(1997)

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&

$$

SHORT TERM...LASCODY
LONG TERM....VOLKMER




AREA FORECAST DISCUSSION

National Weather Service Lincoln IL

 933 AM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 922 AM CST TUE DEC 22 2015

Large shield of stratus remains in place over the area this
morning, with cirrus starting to move in on top of it west of the
Illinois River. While most of the computer models show some
scouring out of the low clouds, our morning sounding showed a
rather a rather tight inversion around 2000 feet that likely will
not be going anywhere fast. HRRR guidance shows a couple thin
spots trying to form, but largely keeps the low clouds over the
entire area into the evening. The existing sky grids already had a
good handle on that. Because of the extensive clouds, have lowered
highs a couple degrees across the northern CWA, but temperatures
still will get a nice bump upward as the southerly flow gets
stronger this afternoon.

Minor grid updates have been sent, but no changes to the worded
forecast are needed at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 330 AM CST TUE DEC 22 2015

Cold front that triggered scattered showers and thunderstorms across
east-central and southeast Illinois earlier this evening has now
pushed into Indiana, leaving behind cloudy but dry conditions across
the KILX CWA early this morning.  Despite surface high pressure
building into the region, do not think any clearing will occur
today.  Models show a strong subsidence inversion developing at
around 925mb, essentially trapping the lingering boundary layer
moisture in the form of a low overcast.  With such a strong
inversion in place and no appreciable advection to get rid of the
clouds, see little hope for any sunshine today. Due to the
extensive cloud cover, have undercut the MAV guidance numbers,
resulting in high temperatures in the middle to upper 40s.

.LONG TERM...(Tonight through Monday)
ISSUED AT 330 AM CST TUE DEC 22 2015

Warm and unsettled weather will be the rule over the next several
days...with the potential for severe thunderstorms and record high
temperatures on Wednesday and copious amounts of rainfall next
weekend.

As high pressure moves off to the east, increasing southwesterly
flow will bring warmer/more humid air into the region tonight into
Wednesday.  NAM forecast soundings are showing the boundary layer
becoming saturated as increasing moisture flows northward,
suggesting the potential for fog/drizzle tonight.  With low pressure
ejecting out of the Rockies, scattered showers will arrive late
tonight, although the bulk of the precipitation will hold off until
Wednesday.

A potentially volatile day is unfolding on Wednesday as deepening
low pressure tracks from near Kansas City early in the day to Lake
Superior by evening.  Strong southerly winds gusting to between 30
and 40 mph ahead of the approaching system will bring an
unseasonably warm and humid airmass into Illinois, with afternoon
high temperatures climbing to near record levels in the middle 60s
and surface dewpoints reaching the middle to upper 50s.  Models
continue to show strong instability developing for this time of
year, with NAM SBCAPES of 500-1000J/kg and lifted index values of -2
to -4C. At the same time, 0-6km bulk shear will increase to between
70 and 80kt along/south of the I-70 corridor.  Latest Day 2
convective outlook from SPC now places all areas east of the
Illinois River under a Slight Risk for severe.  Based on current
projections and model forecast parameters, it appears the primary
severe weather threats will be damaging wind gusts and large hail,
although an isolated tornado will also be possible given the
increasing shear values.  The main time frame for severe will be
during the afternoon east of the Illinois River, shifting to
along/east of the I-57 corridor by early evening.  Cold front will
sweep through the region by around midnight, with rain chances
ending overnight.

Once the Wednesday system departs, quiet weather will be on tap for
both Thursday and Friday with dry conditions and mild high
temperatures in the 40s and 50s.  After that, a return to warm/wet
weather is in store by next weekend as deep-layer southwesterly flow
re-establishes itself across the central/eastern CONUS in advance of
the next major storm system.  All models show an upper trough
digging southward across the western CONUS late in the week,
eventually forming a closed low over the Desert Southwest by
Saturday.  How quickly this feature ejects northeastward is still in
question, with the 00z Dec 22 GFS showing a much faster solution
than the ECMWF.  With such a deep closed low expected to form and
essentially cut itself off from the main flow well to the north,
think slower is the way to go.  As a result, have trended toward the
ECMWF from Saturday through Monday.  The ECMWF shows rain spreading
northward well ahead of the upper low along a prevailing baroclinic
zone Saturday/Saturday night.  After that, rain will continue
through early next week...although there is some indication that a
northern stream short-wave may temporarily push the frontal boundary
a bit further southward and possibly bring a break in the precip
late Sunday into Monday before the upper low tracks into the region
by Monday night into Tuesday.  At this point, will just keep PoPs
going right through the period and will make adjustments as
necessary as better model agreement is achieved.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 528 AM CST TUE DEC 22 2015

IFR conditions at all sites at the start and based on satellite
trends and that a sfc ridge is moving over the area, which should
strengthen any inversion already in place, thinking is that the
clouds below 1kft will not be going anywhere. Low sun angle will
not help either. Thinking is that cig heights at SPI and DEC could
come up to 1kft around mid morning, but other sites will remain
IFR until sometime late afternoon. Unfortunately do not see the
inversion ending this evening and HiRes models hinting at possible
dense fog occurring in the area this evening. So, have included an
entry for IFR conditions returning this evening and this could
last through overnight. HiRes models also showing lower vis with
the fog. Unsure how low it will get with no radiation cooling
occurring under cloudy skies. Think fog will form due to increased
low level moisture/dewpoints. Will just have vis drop to 1sm BR,
but it could go lower...will let next forecast take a closer look
at that. Winds will be westerly ahead of the ridge, but then
become southwesterly, then southeasterly this afternoon, and
continuing through the evening.


&&

.CLIMATE...
ISSUED AT 932 AM CST TUE DEC 22 2015

Record highs for Wednesday:

Bloomington/Normal......... 63 in 1933
Champaign/Urbana........... 64 in 1933
Charleston/Mattoon......... 69 in 1933
Danville................... 65 in 1933
Decatur.................... 66 in 1933
Effingham.................. 68 in 1933
Jacksonville............... 70 in 1933
Lincoln.................... 65 in 1933
Olney...................... 67 in 1931
Peoria..................... 65 in 1933
Springfield................ 66 in 1933

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Auten
CLIMATE...Geelhart




AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 607 AM CST TUE DEC 22 2015

...AVIATION UPDATE...

.SYNOPSIS...
ISSUED AT 337 AM CST TUE DEC 22 2015

WEAK SURFACE RIDGE IS BUILDING INTO THE AREA EARLY THIS AM.
SATELLITE AND OBS SHOW STRATUS BLANKETING THE ENTIRE AREA AND
MUCH OF THE MIDWEST... WITH THE BACK EDGE NEAR THE MISSOURI
RIVER VALLEY SHOWING LITTLE MOVEMENT HOLDING FIRM BENEATH STRONG
850 MB INVERSION. WEAK ISENTROPIC ASCENT AND WEAK CONVERGENCE
WITH SURFACE TROUGH PRODUCED PATCHY TO AREAS OF FOG AND DRIZZLE
LAST EVENING INTO THE OVERNIGHT... BUT SEEING A DIMINISHING TREND
EARLY THIS AM AS THIS LIFT MIGRATES EAST. WATER VAPOR SHOWS
UPPER LEVEL SHORTWAVE MOVING ACROSS THE UPPER MIDWEST WITHIN
SEMI-ZONAL FLOW PATTERN. MUCH STRONGER WAVE WAS NOTED OVER THE
NORTHERN ROCKIES IN LEFT EXIT REGION OF VIGOROUS UPPER LEVEL JET
NOSING FROM EASTERN PACIFIC INTO THE WESTERN CONUS. THIS SYSTEM
LOOKS TO SHIFT ACROSS THE UPPER MIDWEST ON WEDNESDAY BRINGING
OUR NEXT ROUND OF WET WEATHER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN CHALLENGES ARE CLOUD TRENDS AND IMPACT ON HIGHS... THEN RAIN
CHANCES LATER TONIGHT.

DONT FORESEE MUCH EROSION OF THE STRATUS THIS AM WITH SFC RIDGE
SLIDING ACROSS REGION WITH LIMITED MIXING AND STRONG 850 MB
INVERSION IN PLACE. HOWEVER... REMAINS TO BE SEEN WITH PASSAGE
OF THE MID LEVEL WAVE THIS AM IF INCREASING SUBSIDENCE IN WAKE
CAN HELP BRING ABOUT SOME EROSION AND NOTICING LAST FEW RUNS OF
HRRR DEPICT SOME DECREASE IN LOWER CLOUDS NORTH LATE AM INTO THE
PM. SATELLITE TRENDS ALSO SHOW LITTLE MOVEMENT TO BACK EDGE OF THE
STRATUS NEAR THE MISSOURI RIVER VALLEY EARLY THIS AM... AND SOME
OF THE HI-RES GUIDANCE IS PRETTY AGGRESSIVE IN ERODING THIS FROM
THE SOUTH THIS AFTERNOON INTO EASTERN IA AND WESTERN IL... BUT
NOTICING HRRR TRENDING SLOWER WITH THIS PROCESS AND WOULD SUGGEST
SOME EROSION UP TO OUR SOUTHERN CWA BUT MAINLY FURTHER SOUTH.
DO FEEL SOME EROSION OF STRATUS IS LIKELY ESPECIALLY ON THE WEST
AND SOUTH SIDE OF DECK WITHIN DEVELOPING STRONGER SOUTHERLY FLOW
AND MIXING... BUT ALSO EXPECT INCREASING HIGH CLOUDS AND WITH
THE FLOW GENERALLY SSE NOT FEELING GOOD ON PROSPECTS FOR MUCH IN
WAY OF SUNSHINE TODAY AND THUS STAYED WITH CLOUDY-MOCLDY SKY
FORECAST TODAY. AS A RESULT OF STAYING PESSIMISTIC WITH CLOUDS
LOWERED HIGHS A TOUCH AND SIDED ON COOL SIDE OF GUIDANCE BLEND
WITH RANGE AROUND 40 TO MID 40S. HOWEVER... IF NO LIFTING OR
THINNING OF STRATUS OCCURS THEN WILL BE COLDER AND MORE IN RANGE
OF MID 30S NORTH TO LOWER 40S SOUTH. ON THE OTHER SIDE OF THIS
IF WE WERE TO SEE MORE EROSION OF STRATUS THIS AFTERNOON WITH
ONSET OF GUSTY SSE WINDS AND BETTER MIXING THEN COULD EASILY SEE
HIGHS WELL INTO THE 40S TO LOWER 50S. BOTTOM LINE... AS CLOUD
TRENDS GO... SO GO TEMPS. TYPICALLY BETTER TO STAY CONSERVATIVE/
PESSIMISTIC WITH CLOUD AND TEMP TRENDS THIS TIME OF YEAR... AS
DECEMBER IS OUR CLOUDIEST MONTH.

AS FOR WINDS TODAY... SHOULD BECOME GUSTY BY AFTERNOON FROM S/SE
15-25 MPH... WITH TIGHTENING PRESSURE GRADIENT BETWEEN NORTHERN
PLAINS TO LEE SIDE CYCLONES AND GREAT LAKES HIGH PRESSURE RIDGE.
WINDS LIKELY TO REMAIN OCCASIONALLY GUSTY TONIGHT WITH CONTINUED
RAMPING UP OF LOW LEVEL JET AND LINGERING SFC PRESSURE GRADIENT.

ISENTROPIC ASCENT/WARM ADVECTION WITH STRENGTHENING LOW LEVEL JET
SHOULD FOSTER INCREASING SHOWER ACTIVITY OVERNIGHT... ESPECIALLY
WEST AND SOUTHWEST OF QUAD CITIES. CANT RULE OUT A RUMBLE OF
THUNDER ESPECIALLY FAR SOUTHWEST CWA WITHIN PLUME OF STEEP LAPSE
RATES 7-8C/KM IN 600-750 LAYER... BUT FEELING FAIRLY ISOLATED AND
HAVE LEFT OUT MENTION ATTIM.

TEMPS SHOULD DROP VERY LITTLE EARLY THIS EVENING AND PRETTY MUCH
BE STEADY TO GRADUALLY RISING TONIGHT WITH CONTINUED WARM
ADVECTION. DEPENDING ON WHAT TEMPS DO TODAY... ITS VERY POSSIBLE
TO SEE HIGHS FOR THE DAY SOME AREAS OCCUR THIS EVENING...
ESPECIALLY NORTHERN CWA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR
PRECIPITATION AND THE CHANGING GUIDANCE.  GUIDANCE HAS NOT SETTLED
ON ANY SOLUTIONS PAST TOMORROW.  THIS LEADS TO AN OVERALL POOR
CONFIDENCE IN THE FORECAST.  MAIN ISSUE WITH THIS IS THAT SOME OF
THE MODEL SOLUTIONS SUGGEST THE POTENTIAL FOR A SIGNIFICANT RAINFALL
EVENT BOTH WEDNESDAY AND AGAIN TOWARDS THE END OF THE WEEKEND. THESE
EVENTS...IF THEY OCCUR WOULD ONLY EXASPERATE AN ALREADY ATYPICAL
DECEMBER HYDRO EVENT.

WEDNESDAY...WEDNESDAY NIGHT...

MODELS ARE IN GOOD AGREEMENT WITH THE TRACK OF THE LOW ACROSS THE
AREA. MUCH LIKE YESTERDAY...TEMPERATURES WILL BE THE 40S TO 50S
ACROSS THE CWA AND MOISTURE STREAMS INTO THE AREA.  WITH PWATS WELL
ABOVE NORMAL AND APPROACHING 1 INCH ACROSS THE AREA...THE POTENTIAL
FOR MODERATE RAINFALL EXISTS.  IT APPEARS THAT WE ONCE AGAIN HAVE A
THREAT FOR THUNDERSTORMS WITH THIS SYSTEM AS THE CLEAR SLOT MAKES
ITS WAY INTO THE AREA.  LAPSE RATES SHOULD STEEPEN IN THE MIXED
PHASE REGION OF AN UPDRAFT...THIS INCREASES THE CHANCES FOR
THUNDER...ESPECIALLY SOUTH AND THEN EAST OF THE QC.  SPC HAS THIS
AREA IN A MARGINAL RISK FOR SEVERE WEATHER ON WEDNESDAY WITH THE
SLIGHT RISK NOT FAR TO OUR EAST.  MY GUT IS TELLING ME THAT THE BEST
CHANCE FOR SEVERE WILL BE WELL TO OUR EAST ASSOCIATED WITH THE H85
JET.  THAT BEING SAID...IF WE WERE TO GET SEVERE WEATHER IT WOULD BE
ASSOCIATED WITH THE CLEAR SLOT IN THE AFTERNOON.  HIRES MODELS
PREDICT A BROKEN LINE OF CONVECTION ALONG THIS INTERFACE.  I THINK
THAT HAIL WOULD BE THE MAIN THREAT IF SEVERE WEATHER OCCURRED.  I
ALSO THINK A BRIEF WEAK SPIN UP IS NOT OUT OF THE QUESTION.
AGAIN...I HAVE VERY LOW CONFIDENCE IN THIS OCCURRING.  WILL MENTION
THE MARGINAL RISK FOR SEVERE WEATHER IN THE HWO WITH THE HAIL THREAT
FOR WEDNESDAY.  ONCE THE SYSTEM MOVES OUT...THE GEM TRIES TO SNEAK
IN ANOTHER WAVE ALONG THE BOUNDARY OVERNIGHT.  I DO NOT THINK THIS
WILL HAPPEN AS IT IS THE OUTLIER OF THE REST OF THE MODELS.  AS SUCH
I DOWNPLAYED IT.  IF IT IS RIGHT...WE COULD SEE SOME SNOW
ACCUMULATION ACROSS NW ZONES.

THURSDAY THROUGH SATURDAY...

MODELS IN GOOD AGREEMENT FOR A QUIET CHRISTMAS EVE AND CHRISTMAS DAY
ACROSS THE AREA WITH HIGH PRESSURE ENTRENCHED ACROSS THE AREA.  THE
POTENTIAL EXISTS FOR SOME CLEARING AS WELL ON CHRISTMAS DAY.  AFTER
CHRISTMAS DAY...INTO SATURDAY...THE GFS AND ECMWF STALL A BOUNDARY
TO OUR SOUTH.  OVERRRUNING MOISTURE MAY GRAZE THE AREA WITH RAIN AND
EVEN SOME RAIN/SNOW MIX ACROSS THE FAR NORTH FRIDAY NIGHT INTO
SATURDAY.  FOR THE MOST PART THE HEAVIEST PRECIP STAYS TO THE SOUTH.
PAST THIS...THE MODELS DIVERGE.

PAST SATURDAY...

WITH GUIDANCE JUMPING RUN TO RUN PAST SATURDAY IM GOING TO DISCUSS
EACH MODELS GUIDANCE AND SUGGESTED OUTCOMES AND THEN DISCUSS WHY I
WENT A COMPROMISE BETWEEN THE GFS AND ECMWF.  NEEDLESS TO SAY...THE
EXTENDED FORECAST IS FULL OF BUSY WEATHER...AND IF THE GFS IS
CORRECT...WE COULD SEE AN ADDITIONAL 2 TO 4 INCHES AND POSSIBLY UP
TO 5 INCHES THROUGH THE NEXT TEN DAYS.

GFS...

THE RECENT GFS RUNS HAVE PUSHED AN EXTREMELY POTENT...NEGATIVELY
TILTED SYSTEM INTO THE AREA.  THIS PULLS A DEEP LOW ACROSS CENTRAL
IOWA.  WITH THE STALLED BOUNDARY TO OUR SOUTH...DEEP MOISTURE WOULD
QUICKLY SURGE INTO THE AREA.   60 DEGREE TEMPS ARE FORECAST FOR THE
FAR SE WITH THIS SYSTEM.  THE WARM SECTOR...WITH BACKED
WINDS...WOULD ROLL OVER THE AREA...LIKELY LEADING TO THUNDERSTORMS
AND INCREASED RAINFALL ACROSS THE AREA.  THE GFS HAS 1 TO 3+ INCHES
OF RAIN IN THIS EVENT.  IF THIS WERE TO OCCUR...WE WOULD LIKELY NOT
HAVE MUCH TIME FOR WATER FROM YESTERDAYS EVENT AND WEDNESDAY EVENT
TO ROUTE THROUGH THE RIVERS...MEANING HIGHER RIVERS AND POSSIBLY
INCREASED FLOODING.   THE NORTHERN EDGE OF THE CWA WOULD EXPERIENCE
A WINTRY MIX INTO SUNDAY NIGHT AND MONDAY MORNING.  AT THIS TIME
HAVE A RA/SN/PL MIX.  THIS SOLUTION WOULD BE THE WORST FROM A HYDRO
POINT OF VIEW.  I HAVE LOW CONFIDENCE IN THIS OCCURRING.

ECMWF...

THE EURO IS MUCH SLOWER AND ACTUALLY KEEPS THE LOW TO OUR SOUTH
LONGER.  THIS WOULD HELP TO ROUTE MORE WATER OUT OF THE FLOW.
EVENTUALLY ON TUESDAY...THE LOW LIFTS THROUGH THE AREA AND HAS LOWER
...LESS THAN AN INCH QPF...ALONG WITH IT.  THIS WOULD BE A MUCH
BETTER SOLUTION FROM A HYDRO POINT OF VIEW.  MY CONFIDENCE IS
SLIGHTLY HIGHER IN THIS SCENARIO THAN THE GFS...NONETHELESS IT IS
LOW.

THE BOTTOM LINE...

IM STRUGGLING TO DEVELOP THE CONFIDENCE TO TOTALLY ELIMINATE THE GFS
SOLUTION FROM NEXT WEEK. THE GFS HAS CONSISTENTLY DROPPED 1 TO 2
INCHES OF QPF ACROSS CENTRAL MO. A SMALL SHIFT NORTH INTO OUR AREA
IS NOT UNREASONABLE. HOWEVER...IT HAS JUMPED AROUND A LOT MORE
THAN THE EURO AS OF LATE. THIS IS WHY I AM OKAY WITH THE BLEND
THAT I HAVE. UNTIL THE MODELS AGREE ON A SOLUTION THIS WILL
CONTINUE. OBVIOUSLY THESE DIFFERENCES IN SOLUTION MEAN A MAJOR
DIFFERENCE IN POTENTIAL IMPACTS. WHILE I DONT WANT TO MINIMALIZE
THESE IMPACTS...IT IS IMPORTANT TO REMEMBER WE ARE ALMOST 7 DAYS
OUT. EXPECT CHANGES TO THE FORECAST FOR EARLY NEXT WEEK...SOME OF
THESE CHANGES COULD BE SIGNIFICANT...THAT IS THE BOTTOM LINE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 544 AM CST TUE DEC 22 2015

STRATUS WITH MAINLY IFR CIGS BLANKETING THE REGION EARLY THIS AM.
BELIEVE STRATUS WILL REMAIN IN PLACE THROUGH 18Z WITH SFC RIDGE
AND ATTENDANT WEAK MIXING ALONG WITH STRONG 850 MB INVERSION...
WITH GRADUAL LIFTING OF CIGS FROM IFR TO LOWER MVFR THROUGH 18Z.
GENERALLY LOWER MVFR CIGS ANTICIPATED THIS AFTERNOON WITH SOME
EROSION OF STRATUS AND IMPROVEMENT TO VFR POSSIBLE... WITH BRL
GENERALLY SHOWN TO HAVE BEST CHANCE AT VFR THIS AFTN/EARLY EVE
ALTHOUGH CANT BE RULED OUT ELSEWHERE GIVEN INCREASING WINDS AND
MIXING... BUT CONFIDENCE TOO LOW AND LEFT OTHER SITES
(DBQ/CID/MLI) IN LOWER MVFR THIS AFTN. ALL SITES THEN TRANSITION
BACK DOWN TO IFR TONIGHT AHEAD OF NEXT STORM SYSTEM. SOME SHOWERS
LIKELY TO DEVELOP LATE TONIGHT ESPECIALLY SOUTHEAST IA AND HAVE
VCSH WORDING FOR NOW AT BRL. POTENTIAL ALSO FOR LOW LEVEL WIND
SHEAR LATE TONIGHT INTO MID AM WED... BUT WITH POTENTIAL GUSTY SFC
WINDS IN TIGHTENING PRESSURE GRADIENT HAVE LEFT OUT MENTION ATTIM.
WINDS SHIFT FROM W/SW TO SE BY THIS AFTERNOON INTO TONIGHT AND
INCREASE TO 10-15 KTS WITH OCCASIONAL GUSTS.

&&

.HYDROLOGY...
ISSUED AT 247 AM CST TUE DEC 22 2015

RAINFALL AMOUNTS OF A QUARTER INCH TO THREE QUARTERS OF AN INCH FELL
OVER THE PAST 24 HOURS GENERALLY SOUTH OF A LINE FROM MARENGO TO
BELLEVUE. WITH SATURATED GROUND...NEARLY ALL OF THIS RAINFALL WILL
BE RUNOFF AND HAVE ALREADY SEEN SOME LOCAL RESPONSES ON SOME OF THE
RIVERS. THIS ADDITIONAL RAINFALL WILL INCREASE THE FORECAST CRESTS A
BIT ON SOME RIVERS...AND HAS PUSHED THE FORECASTS FOR THE LOWER END
OF THE SKUNK AND DES MOINES RIVERS OVER FLOOD STAGE. ALONG THE
MISSISSIPPI...AFTER SEEING THE RIVER LEVELS FALL OR BECOME STEADY
OVER THE PAST 24 HOURS...MOST SITES WILL SEE THE RIVER BEGIN RISING
AGAIN...WITH THIS TREND CONTINUING THROUGH MUCH OF THE WEEK.

MOST FORECASTS ARE FOR THE RIVER LEVELS TO FALL BY THE END OF THIS
WEEK. HOWEVER...ADDITIONAL STORM SYSTEMS ARE LOOKING TO PASS ACROSS
THE AREA THROUGH THE NEXT WEEK WITH PRECIPITATION FALLING AS RAIN.
THE FIRST OF WHICH WILL BE WEDNESDAY. THERE IS QUITE A BIT OF
UNCERTAINTY IN HOW MUCH RAIN WILL FALL AND WHAT AREAS WILL GET HIT
YET...BUT LIKELY WILL BE ADDITIONAL RISES AND FURTHER POTENTIAL FOR
FLOODING ON SOME AREA RIVERS THROUGH THE CHRISTMAS HOLIDAY WEEKEND.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...MCCLURE
SHORT TERM...MCCLURE
LONG TERM...GIBBS
AVIATION...05
HYDROLOGY...GIBBS




AREA FORECAST DISCUSSION

NWS NEW ORLEANS LA

 707 AM CST TUE DEC 22 2015

...SOUNDING DISCUSSION...
THE SOUNDING THIS MORNING IS SATURATED THROUGH AN INVERSION IN
THE FIRST 500 FT AND IS REPRESENTATIVE OF THE DENSE FOG CONDITIONS
IN PLACE. THE REST OF THE PROFILE DEPICTS A VERY MOIST AIRMASS
OVERALL WITH PW AT 1.73 INCHES... WHICH IS NEAR THE DAILY MAX IN
THE SPC CLIMATOLOGY. THE ATMOSPHERE HAS A BIT OF INSTABILITY WITH
CAPE IN THE MIXED LAYER AT 900 J/KG AND MOST UNSTABLE AT 1100
J/KG. THERE IS JUST A LITTLE BIT OF A WARM LAYER AT ABOUT 800 MB.
THIS FEATURE IS MORE PRONOUNCED ON THE LAKE CHARLES AND JACKSON
SOUNDINGS. WARM AIR OR AN INVERSION IN THIS LAYER WILL NEED TO BE
MONITORED AS A POTENTIAL LIMITING FACTOR ON CONVECTION TODAY AND
POSSIBLY TOMORROW. FLOW IS SOUTHWEST THROUGHOUT WITH PEAK WIND 80
KTS AT 200 MB.

KRAUTMANN

&&

.PREV DISCUSSION... /ISSUED 356 AM CST TUE DEC 22 2015/

SHORT TERM...
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST
THIS MORNING. THIS 00Z SOUNDING FROM YESTERDAY AFTERNOON HAD A
RECORD HIGH PRECIP WATER VALUE OF 1.92" WHICH IS PROBABLY IN THE
UPPER 90TH PERCENTILE FOR THE ENTIRE MONTH OF DECEMBER. THUS
SHOULDN/T BE ANY SURPRISE THAT WIDESPREAD FOG HAS DEVELOPED OVER
MUCH OF THE AREA. MANY OBSERVATIONS INDICATE VISIBILITIES OF
AROUND A HALF MILE OR LESS. SAMPLING INTERSTATE CAMERAS ALSO SHOWS
WHAT APPEARS TO BE LESS THAN 1/4 MILE VISIBILITIES IN SOME
LOCATIONS AS WELL. ALTHOUGH THE ENTIRE CWA PROBABLY DOES NOT NEED
A DENSE FOG ADVISORY...LEAVE THEM ABSENT WOULD PRODUCE A VERY ODD
LOOKING AND CONFUSING PRODUCT. SO WILL BE ISSUING A BLANKET DENSE
FOG ADVISORY FOR THE CWA THROUGH 15Z.

CURRENT RADAR SHOWS FIRST WAVE HEADED EAST ACROSS THE NORTHERN GULF
WATERS. LINGERING SHOWERS PERSIST SIMPLY DUE TO COLUMN SATURATION
AND MINIMAL BUOYANCY. EXTENSIVE CLOUD COVER SHOULD LIMIT WARMING
TODAY TO LOWER 70S ACROSS THE FORECAST AREA. THIS IS A GOOD THING AS
IT WILL LIMIT INSTABILITY POTENTIAL. NEVERTHELESS...A SHORT WAVE IS
PROGGED TO LIFT NORTHEAST OUT OF THE GULF ACROSS THE LOWER HALF OF
THE CWA. HRRR AND NMM AS WELL AS MEDIUM RANGE MODELS ALL PINGING ON
A LARGE SWATH OF NUMEROUS SHOWERS AND THUNDERSTORMS IMPACTING AREAS
SOUTH OF INTERSTATE 10. THE FORECAST POPS HAVE THUS BEEN ADJUSTED
FOR THIS. THE SEVERE POTENTIAL WILL REMAIN ON THE LOW SIDE BUT STILL
EXISTS. MODEL SOUNDINGS DO INDICATE ELEVATED INSTABILITY ACROSS THE
BOARD BUT A WEAK WIND FIELD DURING THE DAYTIME. GOING INTO THE NIGHT
THE WIND FIELD BEGINS TO INCREASE WITH SHEAR VALUES IN THE 40 TO 50
KNOT RANGE. THE QUESTION IS WHETHER OR NOT CELLS WILL BE SURFACE
BASED. IF MODEL SOUNDINGS HOLD TRUE...THEY WONT BE AND THUS THE ONLY
CHANCE TO MIX DOWN STRONGER WINDS THROUGH THE WARM NOSE IS THROUGH
PRECIP LOADING. WILL BE SOMETHING TO WATCH BUT NOT A HIGH CONCERN.
MARINE LOCATIONS WILL BE THE MOST LIKELY FOR STRONGER WIND GUSTS AND
WATERSPOUTS.

THE REAL SEVERE WEATHER THREAT LOOKS TO COME INTO PLAY ON WEDNESDAY.
BROAD LONG WAVE TROUGH ALREADY IN PLACE OVER THE ROCKIES WILL DIG
AND SWING NEGATIVE OVER THE CENTRAL PLAINS DURING THE DAY. DOWN AT
THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
AROUND 1006 MB. TIGHTENING OF THE PRESSURE GRADIENT WILL INCREASE
SURFACE WINDS WHICH WILL THEN AIDE IN THE TRANSPORT OF 70 DEGREE
DEWPOINTS TO POINTS NORTH. PRESUMING THAT SFC TEMPS DO REACH MID 70S
WHILE THESE DEWPOINTS RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP
DURING THE DAY. BOTH GFS AND NAM BUFR SOUNDINGS SHOW SB AND PARCEL
CAPE VALUES OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE
CWA. HELICITY VALUES AREN/T THAT IMPRESSIVE AT 200 M2/S2 BUT
SUFFICIENT. NOT SURPRISING WITH A FAIRLY UNIFORM WIND DIRECTION
THROUGHOUT THE COLUMN. OF MORE IMPORTANCE IS SPEED SHEAR AND JUST
THE VALUE OF THE WINDS THEMSELVES. LOOKING AT 40 TO 50 KNOTS IN THE
BOUNDARY LAYER WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THE
PRECIP WATER VALUE IS IN A PRETTY NICE SWEET SPOT...NOT TOO HIGH AND
NOT TO LOW AT AROUND 1.5 INCHES. ALL OF THAT IS TO SAY THAT THE ODDS
OF SEVERE WEATHER FOR THE DAY WEDNESDAY LOOKING BETTER AND BETTER.
THE MAIN THREATS WILL BE TORNADOES AND DAMAGING WINDS. HOW
WIDESPREAD REMAINS TO BE SEEN. IF SFC TEMPS DONT WARM ENOUGH...WILL
JUST HAVE THE DYNAMICS. IF SOUTHEASTERLY FLOW IS TOO STRONG THAN THE
MARINE LAYER COULD BE PUSHED TOO FAR INLAND AND A WARM NOSE (SHOWN
CLEARLY ON THE GPT SOUNDING) WILL HINDER SFC BASED STORMS.
REGARDLESS...THE POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SPC
SLIGHT FOR THE AREA.

LONG TERM...
RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR CONVECTION ON
THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD HAVE NO
PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW THUNDERSTORMS.
MUCH WEAKER WINDS IN THE COLUMN AND NON-SEVERE CONDUCING WIND
DIRECTIONS WILL LIMIT THE STRENGTH OF ACTIVITY. COVERAGE SHOULD
STILL BE OVER 50 PERCENT FOR THE MOST PART.

CHRISTMAS DAY COULD ACTUALLY HAVE THE LOWEST CHANCE OF RAIN FOR THE
ENTIRE WEEK AS UPPER LEVEL RIDGE CENTERED OVER THE WESTERN ATLANTIC
BUILDS BACK WESTWARD ACROSS THE CWA. PROBLEM IS THAT ITS STILL
CHANCE CATEGORY. ON THE TEMPERATURE SIDE OF THINGS...WILL NOT BE
FEELING TOO WINTER-LIKE WITH LOWS IN THE MID 60S AND HIGHS
APPROACHING 80 DEGREES IN ISOLATED LOCATIONS. A LITTLE PERSPECTIVE
ON HOW WARM IT WILL BE...THE FORECAST LOWS FOR CHRISTMAS DAY MORNING
ARE SEVERAL DEGREES WARMER THAN TYPICAL DAYTIME HIGHS FOR THIS TIME
OF YEAR. MAY NOT BREAK RECORDS BUT NOT TOO FAR OFF EITHER.

POPS TO FALL EVEN MORE DOWN INTO THE 20 TO 30 PERCENT RANGE THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. DIDNT MAKE ANY SIGNIFICANT CHANCES TO POPS DUE TO CHANGING
SOLUTIONS WITH EACH MODEL ITERATION.

MEFFER

AVIATION...

FOG WILL BE THE ISSUE FOR A FEW TERMINALS THIS MORNING. THE
PROBLEMS THAT DENSE FOG WILL DEVELOP FOR A VERY SHORT DURATION THEN
LIFT JUST AS QUICK. HAVE SET PREVAILING TO SHOW VIS AT 2 TO 3SM WITH
TEMPO GROUPS SHOWING DOWN TO 1/4SM. WILL ALSO SHOW TS FOR BTR...HDC
AND ASD MAINLY DURING THE EARLY AFTERNOON. A SEPARATE COMPLEX WILL
AFFECT THE SOUTH SHORE TERMINALS FROM HUM TO NEW AND MSY THROUGH TO
GPT LATE IN THE AFTERNOON AND EVENING HOURS. WILL ALSO KEEP FOG IN
12Z TAF PACK.

MARINE... TS WILL BE RESPONSIBLE FOR PRODUCING SOME STRONG WIND
SPEEDS OVER THE COASTAL WATERS THROUGH TONIGHT. AVOID ANY AREAS
WHERE ARE LOCATED. LARGER SCALE WINDS SHOULD BEGIN TO INCREASE OVER
THE OUTER WATERS TONIGHT WITH EXERCISE CAUTION/SMALL CRAFT ADVISORY
HEADLINES LIKELY TO BE NECESSARY ON WEDNESDAY. CONDITIONS SHOULD
EASE A BIT ON THURSDAY WITH RELATIVELY QUIET WEATHER UNTIL NEXT
SUNDAY AHEAD OF A STRONGER SYSTEM MOVING THROUGH THE CENTER OF THE
COUNTRY.

DECISION SUPPORT...

DSS CODE....GREEN. DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.

DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN  = NO WEATHER
IMPACTS THAT REQUIRE ACTION BLUE   = LONG FUSED
WATCH/WARNING/ADVISORY IN EFFECT OR HIGH         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
        ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO
MODERATE RISK SEVERE; NEARBY         TROPICAL EVENTS; HAZMAT OR
OTHER LARGE EPISODES RED    = FULL ENGAGEMENT FOR MODERATE RISK SVR
AND/OR DIRECT         TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  72  63  76  66 /  70  80  90  60
BTR  74  64  75  66 /  80  80  90  40
ASD  71  64  74  67 /  90  80  90  70
MSY  72  64  75  70 /  90  90  80  70
GPT  70  64  71  68 /  90  80  90  70
PQL  72  64  73  69 /  90  80  90  70

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR LAZ034>037-
     039-040-046>050-056>072.

GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR GMZ530-532-
     534-536-538-550-552-555.

MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ068>071-
     077-080>082.

GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR GMZ532-534-
     536-538-550-552-555.

&&

$$




AREA FORECAST DISCUSSION

NWS JACKSON MS

 721 AM CST TUE DEC 22 2015

.UPDATE...

HAVE EXPANDED THE DENSE FOG ADVISORY TO COVER THE ENTIRE AREA BASED
ON CURRENT TRENDS AND NEAR TERM HRRR GUIDANCE WHICH BEGINS TO FOCUS
MORE DENSE FOG OVER EASTERN MS FOR THE NEXT COUPLE OF HOURS. HAVE
ALSO EXTENDED IT BY AN HOUR BASED ON THESE TRENDS. /EC/

&&

.PREV DISCUSSION... /ISSUED 516 AM CST TUE DEC 22 2015/

UPDATE...UPDATED TO INCLUDE DENSE FOG ADVISORY UNTIL 9AM FOR
PORTIONS OF EXTREME SOUTHEAST ARKANSAS...NORTHEAST LOUISIANA AND
WEST CENTRAL MISSISSIPPI. /22/

PREV DISCUSSION... /ISSUED 444 AM CST TUE DEC 22 2015/

SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...MOST OF THE SHOWERS
HAVE DISSIPATED THIS MORNING AS THE DEEP MOISTURE HAS SHIFTED TO THE
EAST AND SOUTH OF THE AREA. PATCHY AREAS OF DENSE FOG ARE OCCURRING
AND A LIMITED POTENTIAL FOR DENSE FOG IS ALREADY IN THE HWO.
ISOLATED SHOWERS WILL CONTINUE TO BE POSSIBLE THROUGH THE MORNING
HOURS...BUT AS THE DEEP MOISTURE PUSHES BACK NORTH ACROSS THE
AREA...SHOWERS AND THUNDERSTORMS WILL ONCE AGAIN RETURN THIS
AFTERNOON THROUGH THE EVENING HOURS. HI-RES MODELS INDICATE THAT A
COMPLEX OF STORMS WILL DEVELOP OVER THE NORTH CENTRAL GULF AND MOVE
ACROSS AREAS MAINLY SOUTH OF THE NATCHEZ TRACE CORRIDOR LATER THIS
AFTERNOON THROUGH THE EVENING HOURS. LIMITED INSTABILITY AND SHEAR
WOULD SUGGEST THE ACTIVITY WILL REMAIN BELOW STRONG TO SEVERE
LIMITS...BUT WITH ALL OF THE RECENT RAINFALL SOME LOCALIZED FLOODING
MAY BE POSSIBLE.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE
OVERNIGHT...BUT THE MAIN SHOW LOOKS TO BE ON WEDNESDAY ACROSS THE
AREA. A STRONG POLAR JET WILL DEEPEN A NEGATIVELY TILTED TROUGH
OVER THE PLAINS WITH A SURFACE LOW MOVING FROM THE CENTRAL PLAINS
INTO THE GREAT LAKES BY WEDNESDAY EVENING. THE BEST FORCING WITH
THIS SYSTEM CONTINUES TO LOOK LIKE IT WILL BE TO THE NORTH OF OUR
AREA...BUT WITHIN OUR AREA THE BEST FORCING WILL GENERALLY BE NORTH
OF THE I-20 CORRIDOR. THE NAM CONTINUES TO BE THE MOST ROBUST MODELS
FOR THE POTENTIAL FOR SEVERE WHILE THE ECMWF IS MORE BEARISH. ALL OF
THE INSTABILITY AND SHEAR PARAMETERS LOOK TO SUPPORT THE POTENTIAL
FOR SEVERE ACROSS THE AREA...BUT THE MAIN LIMITING FACTOR LOOKS TO
BE THE AMOUNT OF FORCING WITH LIMITED HEIGHT FALLS...ESPECIALLY
ALONG AND SOUTH OF OF THE I-20 CORRIDOR. THERE ARE ACTUALLY HEIGHT
RISES ACROSS THE AREA AS WE GET INTO THE LATE AFTERNOON/EARLY
EVENING HOURS. EVEN WITH THESE FACTORS ANY STORMS THAT DUE DEVELOP
WILL HAVE THE ABILITY TO BECOME SEVERE GIVEN THE INSTABILITY AND
VERY STRONG SHEAR. WITH THE CWASP SIG TOR INGREDIENTS CONTINUE TO
REMAIN VERY HIGH OVER OUR AREA...WILL UPGRADE AREAS MAINLY NORTH OF
THE I-20 CORRIDOR TO ELEVATED IN THE HWO AND GRAPHICASTS. HEAVY
RAINFALL WILL ALSO HAVE TO BE MONITORED ONCE AGAIN GIVEN THE
RAINFALL AMOUNTS THAT HAVE ALREADY BEEN RECEIVED AND WILL FALL OVER
THE NEXT COUPLE OF DAYS.

EXPECT THE SEVERE POTENTIAL TO SHIFT EAST OF THE AREA WEDNESDAY
NIGHT...BUT SHOWERS WILL CONTINUE TO BE POSSIBLE THROUGH THE NIGHT
GIVEN THE DEEP LAYER MOISTURE THAT WILL REMAIN OVER MUCH OF THE
AREA. /15/

LONG TERM...THURSDAY THROUGH MONDAY...COME THURSDAY MORNING A
STALLED FRONT WILL BE DRAPED SOUTHWEST TO NORTHEAST ACROSS OUR CWA.
MODELS DIFFER ON HOW FAR SOUTHEAST THE STALLED FRONT WILL BE IN OUR
CWA BUT CONSENSUS PLACES IT SOUTHEAST OF THE NATCHEZ TRACE.
NORTHWEST OF THE STALLED FRONT PWATS WILL BE KNOCKED DOWN BELOW ONE
INCH WITH SURFACE DEW POINTS IN THE UPPER 50S TO LOWER 60S.
SOUTHEAST OF THE BOUNDARY A MOIST AIR MASS WILL REMAIN WITH DEW
POINTS AROUND 70 DEGREES AND PWATS AROUND AN INCH AN A HALF. PLENTY
OF CLOUD COVER AND ONGOING CONVECTION IS EXPECTED ALONG AND
SOUTHEAST OF THE BOUNDARY BUT AFTERNOON HIGHS WILL TOP OUT WELL
ABOVE NORMAL IN THE UPPER 70S. THESE TEMPERATURES WILL CONTRIBUTE TO
MLCAPE VALUES OF 1000-1300J/KG IN AN ENVIRONMENT WHERE THE 0-6KM
BULK SHEAR WILL STILL BE AROUND 45KTS AND 0-3KM STORM RELATIVE
HUMIDITIES AOA 200M2/2. A FEW STRONG TO SEVERE STORMS WILL BE
POSSIBLE DURING THE HEAT OF THE DAY OVER OUR SOUTHEAST WITH DAMAGING
WIND GUSTS BEING THE MAIN THREAT. THURSDAY NIGHT OUR WINDS ALOFT
BACK MORE TO THE SOUTH SOUTHWEST AHEAD OF A DEEPENING TROUGH OVER
THE WESTERN CONUS. SURFACE RIDGING FROM THE ATLANTIC WILL NOSE BACK
ACROSS THE GULF COAST STATES. THIS WILL HELP THE BOUNDARY MOVE BACK
NORTH AS A WARM FRONT THURSDAY NIGHT AND SERVE TO FOCUS FOR
CONVECTION FRIDAY. MODEL CONSENSUS HAS THE BOUNDARY JUST NORTHWEST
OF OUR CWA BY NOON FRIDAY RESULTING IN PWATS GREATER THAN AN INCH
AND A HALF OVER OUR WHOLE CWA. GREATEST POPS WL BE CARRIED OVER OUR
NORTHWEST ZONES FRIDAY BUT THERE WL BE A CHANCE FOR RAIN AREAWIDE.
THE DEEPENING TROUGH OVER THE WESTERN CONUS WILL CLOSE OFF OVER THE
DESERT SOUTHWEST BY SATURDAY MORNING AND SWING EAST TO THE TEXAS BIG
BEND REGION BY SUNDAY MORNING. THE MODELS BEGIN TO DIVERGE WITH THE
TRACK OF THE CLOSED LOW SUNDAY INTO TUESDAY WITH THE GFS BEING THE
MOST PROGRESSIVE AND FASTEST BRINGING THE ASSOCIATED COLD FRONT
ACROSS OUR CWA SUNDAY NIGHT. THE ECMWF IS THE SLOWEST WITH THE
CLOSED LOW AND BRINGS THE ASSOCIATED CLOD FRONT THROUGH OUR CWA
MONDAY NIGHT. BOTH MODELS AGREE THAT WARMER THAN NORMAL TEMPERATURES
WITH MOSTLY DIURNALLY DRIVEN RAIN CHANCES WILL CONTINUE OVER OUR CWA
THROUGH THE WEEKEND. HAVE USED A BLEND AND LEANED TOWARD A LITTLE
SLOWER FROPA IN LINE WITH CONSENSUS FROM MONDAY`S RUNS WITH MONDAY
BEING THE MAIN RAIN DAY. THERE STILL REMAIN INDICATION OF SOME
POTENTIAL FOR SEVERE STORMS ALONG AND AHEAD OF THE FRONT. /22/

AVIATION...MOST SITES ARE IFR/LIFR EARLY THIS MORNING AND EXPECT
THESE CONDITIONS TO CONTINUE THROUGH MOST OF THE PERIOD WITH A
CHANCE FOR SHOWERS AND THUNDERSTORM THIS AFTERNOON AND EVENING. THE
WINDS WILL REMAIN OUT OF THE SOUTH AT 6-9KTS ACROSS THE AREA./15/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       74  63  78  64 /  52  71  77  66
MERIDIAN      73  63  76  65 /  76  80  81  68
VICKSBURG     72  64  78  61 /  34  72  78  53
HATTIESBURG   74  64  78  66 /  89  87  82  66
NATCHEZ       74  65  79  65 /  49  79  73  55
GREENVILLE    68  62  77  58 /  18  71  80  49
GREENWOOD     72  64  78  60 /  26  62  80  64

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MSZ018-019-
     025>066-072>074.

LA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR LAZ007>009-
     015-016-023>026.

AR...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR ARZ074-075.

&&

$$

JAN/JAN




AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 520 AM CST TUE DEC 22 2015

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

FORECAST CONCERNS WILL BE POTENTIAL FOR MIXED PRECIPITATION/RAIN/
SNOW THROUGH THE THURSDAY.

LARGE SCALE PATTERNS HAS AN H5 TROUGH ENCOMPASSING MUCH OF THE
U.S. THIS MORNING WITH SHORTWAVE TROUGH ENERGY EMBEDDED IN THE
FLOW OVER THE NORTHERN ROCKIES MOVING INTO THE WESTERN HIGH
PLAINS. LIGHTNING STRIKES WERE NOTED OVER PARTS OF NORTHERN UTAH
AND WYOMING. THIS SHORTWAVE TROUGH WILL ROTATE THROUGH...MAINLY
AFFECTING THE DAKOTAS. THIS WEATHER SYSTEM WILL SPREAD
ACCUMULATING SNOW ACROSS A LARGE PART OF NORTH DAKOTA...NORTH OF
THE TRACK OF THE SURFACE LOW. WATER VAPOR SATELLITE IMAGERY SHOWS
INCREASING HIGHER LEVEL MOISTURE ADVANCING EASTWARD FROM THE WEST
ASSOCIATED WITH A STRONG 160KT H3 JET MOVING INTO THE WEST COAST.

THE LOW LEVEL JET FROM CENTRAL NEBRASKA THROUGH CENTRAL KANSAS
WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA AND INCREASE
TO 50KTS. THIS WILL HELP BREAK UP THE LOW CLOUDS (AND FOG) MIXING
IN SOME OF THE DRY AIR ALOFT. SOUTH WINDS WILL INCREASE TO 15 TO
30 MPH. MID AND HIGH CLOUDS CAN BE EXPECTED THROUGHOUT THE DAY.
H85 TEMPERATURES INCREASE TO +6-+8 DEG C. WARMER HIGHS IN THE 40S
TO LOWER 50S ARE FORECAST.

TONIGHT...THE FRONTAL SYSTEM BECOMES COMPLEX...WITH SURFACE LOW
PRESSURE OVER COLORADO MOVING INTO KANSAS AND THE COLD FRONT
APPROACHES FROM THE WEST WITH THE NORTHERN SYSTEM. BY 06Z AN
INVERTED TROF SHOULD EXTEND NEAR LINCOLN TOWARD SIOUX CITY...WITH
MILD AIR ON THE EAST SIDE OF THE FRONT AND COOLER AIR TO THE WEST.
THERE ARE STILL SOME DIFFERENCES IN THE MODELS AS TO THE EFFECTS
OF THE NORTHERN STREAM SYSTEM AND THE SOUTHERN STREAM SYSTEM.
THERE MAY BE TWO BANDS OF MORE FOCUSED PRECIPITATION WITH LIGHTER
PRECIPITATION IN BETWEEN. BETWEEN 06Z-12Z...THE PRECIPITATION
SHOULD EXPAND IN THESE TWO AREAS. THE GFS DOES NOT REALLY SHOW A
MIX OF PRECIP...HOWEVER THE HRRR EXP/NAM DO HAVE MIXED OF
PRECIPITATION. DO MENTION A MIX ON THE WESTERN PARTS OF THE PRECIP
AREA WITH RAIN WHERE THIS IS SUPPORTED...CONTINUING INTO WEDNESDAY
MORNING...BEFORE MOVING OUT IN THE AFTERNOON. THE 06Z MODELS ARE
COMING IN A LITTLE SLOWER...SO THE TIMING MAY NEED TO BE ADJUSTED.
HIGHS WEDNESDAY SHOULD BE IN THE LOWER 30S TO MID 40S NEAR THE
KANSAS BORDER.

THIS ACTIVE PATTERN CONTINUES WITH A SHORTWAVE MOVING THROUGH LATE
WEDNESDAY NIGHT AND THURSDAY. PRELIMINARY TEMPERATURES APPEAR TO
SUPPORT A MAINLY LIGHT SNOW EVENT. THE NAM IS MORE INTENSE WITH
THIS SHORTWAVE...FARTHER NORTH AND LASTS INTO THE AFTERNOON. FOR
NOW HAVE SOME LIGHT SNOW AMOUNTS MENTIONED.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

THERE ARE STILL SIGNIFICANT DIFFERENCES IN THE EXTENDED. WE
CONTINUE TO MENTION RAIN/SNOW FOR FRIDAY AS A STRONGER TROUGH
MOVES INTO UTAH/WYOMING/COLORADO. THE STORM SYSTEM CLOSES OFF OVER
ARIZONA FRIDAY NIGHT WITH WEAK FORCING OVER THE AREA. A TROUGH IN
THE NORTHERN PLAINS REINFORCES THE COLD AIR A LITTLE FARTHER SOUTH
SATURDAY. THE LARGER DIFFERENCES ARE FOR SUNDAY AND MONDAY WITH
THE GFS TRACK OF THE CLOSED LOW MUCH FARTHER NORTH OVER KANSAS
CITY COMPARED TO THE EC...STILL OVER TEXAS.THE GFS HAS MORE
PRECIP WHILE THE EC IS MORE DRY FOR NEB/IA. UNTIL THERE IS BETTER
AGREEMENT...WE STILL HAVE PRECIP CHANCES MENTIONED IN THESE
PERIODS. TEMPERATURES REMAIN AT OR ABOVE NORMAL FOR THIS TIME OF
YEAR.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 520 AM CST TUE DEC 22 2015

LOW CLOUDS AND FOG CURRENTLY IN PLACE AT KOFK AND KOMA WILL LIFT
AS SOUTHERLY LOW LEVEL FLOW INCREASES THE NEXT SEVERAL HOURS.
AFTER THE LOW CLOUDS MOVE OUT...LOOK FOR VFR CONDITIONS THE REST
OF THE DAY. MOISTURE WILL BE ON THE INCREASE AGAIN TONIGHT AS LIFT
INCREASES WITH APPROACH OF NEXT SHORTWAVE TROUGH. CEILINGS WILL
LOWER WITH MVFR CONDITIONS POSSIBLE AFTER MIDNIGHT. WE SHOULD ALSO
SEE AN INCREASE IN PCPN CHANCES AFTER 06Z.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...MILLER




AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 427 AM CST TUE DEC 22 2015

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

FORECAST CONCERNS WILL BE POTENTIAL FOR MIXED
PRECIPITATION/RAIN/SNOW THROUGH THE THURSDAY.

LARGE SCALE PATTERNS HAS AN H5 TROUGH ENCOMPASSING MUCH OF THE
U.S. THIS MORNING WITH SHORTWAVE TROUGH ENERGY EMBEDDED IN THE
FLOW OVER THE NORTHERN ROCKIES MOVING INTO THE WESTERN HIGH
PLAINS. LIGHTNING STRIKES WERE NOTED OVER PARTS OF NORTHERN UTAH
AND WYOMING. THIS SHORTWAVE TROUGH WILL ROTATE THROUGH...MAINLY
AFFECTING THE DAKOTAS. THIS WEATHER SYSTEM WILL SPREAD
ACCUMULATING SNOW ACROSS A LARGE PART OF NORTH DAKOTA...NORTH OF
THE TRACK OF THE SURFACE LOW. WATER VAPOR SATELLITE IMAGERY SHOWS
INCREASING HIGHER LEVEL MOISTURE ADVANCING EASTWARD FROM THE WEST
ASSOCIATED WITH A STRONG 160KT H3 JET MOVING INTO THE WEST COAST.

THE LOW LEVEL JET FROM CENTRAL NEBRASKA THROUGH CENTRAL KANSAS
WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA AND INCREASE
TO 50KTS. THIS WILL HELP BREAK UP THE LOW CLOUDS (AND FOG) MIXING
IN SOME OF THE DRY AIR ALOFT. SOUTH WINDS WILL INCREASE TO 15 TO
30 MPH. MID AND HIGH CLOUDS CAN BE EXPECTED THROUGHOUT THE DAY.
H85 TEMPERATURES INCREASE TO +6-+8 DEG C. WARMER HIGHS IN THE 40S
TO LOWER 50S ARE FORECAST.

TONIGHT...THE FRONTAL SYSTEM BECOMES COMPLEX...WITH SURFACE LOW
PRESSURE OVER COLORADO MOVING INTO KANSAS AND THE COLD FRONT
APPROACHES FROM THE WEST WITH THE NORTHERN SYSTEM. BY 06Z AN
INVERTED TROF SHOULD EXTEND NEAR LINCOLN TOWARD SIOUX CITY...WITH
MILD AIR ON THE EAST SIDE OF THE FRONT AND COOLER AIR TO THE WEST.
THERE ARE STILL SOME DIFFERENCES IN THE MODELS AS TO THE EFFECTS
OF THE NORTHERN STREAM SYSTEM AND THE SOUTHERN STREAM SYSTEM.
THERE MAY BE TWO BANDS OF MORE FOCUSED PRECIPITATION WITH LIGHTER
PRECIPITATION IN BETWEEN. BETWEEN 06Z-12Z...THE PRECIPITATION
SHOULD EXPAND IN THESE TWO AREAS. THE GFS DOES NOT REALLY SHOW A
MIX OF PRECIP...HOWEVER THE HRRR EXP/NAM DO HAVE MIXED OF
PRECIPITATION. DO MENTION A MIX ON THE WESTERN PARTS OF THE PRECIP
AREA WITH RAIN WHERE THIS IS SUPPORTED...CONTINUING INTO WEDNESDAY
MORNING...BEFORE MOVING OUT IN THE AFTERNOON. THE 06Z MODELS ARE
COMING IN A LITTLE SLOWER...SO THE TIMING MAY NEED TO BE ADJUSTED.
HIGHS WEDNESDAY SHOULD BE IN THE LOWER 30S TO MID 40S NEAR THE
KANSAS BORDER.

THIS ACTIVE PATTERN CONTINUES WITH A SHORTWAVE MOVING THROUGH LATE
WEDNESDAY NIGHT AND THURSDAY. PRELIMINARY TEMPERATURES APPEAR TO
SUPPORT A MAINLY LIGHT SNOW EVENT. THE NAM IS MORE INTENSE WITH
THIS SHORTWAVE...FARTHER NORTH AND LASTS INTO THE AFTERNOON. FOR
NOW HAVE SOME LIGHT SNOW AMOUNTS MENTIONED.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

THERE ARE STILL SIGNIFICANT DIFFERENCES IN THE EXTENDED. WE
CONTINUE TO MENTION RAIN/SNOW FOR FRIDAY AS A STRONGER TROUGH
MOVES INTO UTAH/WYOMING/COLORADO. THE STORM SYSTEM CLOSES OFF OVER
ARIZONA FRIDAY NIGHT WITH WEAK FORCING OVER THE AREA. A TROUGH IN
THE NORTHERN PLAINS REINFORCES THE COLD AIR A LITTLE FARTHER SOUTH
SATURDAY. THE LARGER DIFFERENCES ARE FOR SUNDAY AND MONDAY WITH
THE GFS TRACK OF THE CLOSED LOW MUCH FARTHER NORTH OVER KANSAS
CITY COMPARED TO THE EC...STILL OVER TEXAS.THE GFS HAS MORE
PRECIP WHILE THE EC IS MORE DRY FOR NEB/IA. UNTIL THERE IS BETTER
AGREEMENT...WE STILL HAVE PRECIP CHANCES MENTIONED IN THESE
PERIODS. TEMPERATURES REMAIN AT OR ABOVE NORMAL FOR THIS TIME OF
YEAR.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1130 PM CST MON DEC 21 2015

IFR OR LIFR CONDITIONS WILL PREVAIL AT BOTH KOFK AND KOMA THROUGH
15Z AND ARE EXPECTED TO DEVELOP AT KLNK BY 09Z. MVFR CONDITIONS
THEN DEVELOP AT ALL THREE SITES AFTER 15Z AND VFR CONDITIONS AFTER
21Z.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...FOBERT




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 939 AM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 929 AM CST TUE DEC 22 2015

WEBCAM TRENDS THROUGH 1520 UTC INDICATE THAT THE 700-900 MB DRY
LAYER HAS NOT YET BEEN SUFFICIENTLY ERODED ACROSS CENTRAL NORTH
DAKOTA FOR SNOWFALL TO REACH THE SURFACE. 15 UTC RAP SOUNDINGS
SUGGESTS THE LAYER WILL QUICKLY SATURATE IN THE 16-17 UTC
TIMEFRAME. OVERALL...THE 12 UTC WRF-NMM/ARW...NAM NEST AND 11-14
UTC HRRR ITERATIONS SUPPORT THE TREND FROM THE 00 AND 06 UTC
GLOBAL SUITES OF A SLIGHT NORTHWARD SHIFT IN THE SNOWBAND TODAY AS
COMPARED TO RUNS YESTERDAY...WITH NOW LESS THAN ONE INCH OF SNOW
EXPECTED FOR BISMARCK/MANDAN.

UPDATE ISSUED AT 646 AM CST TUE DEC 22 2015

NO SIGNIFICANT CHANGES WITH THIS UPDATE OTHER THAN TO BLEND THE
LATEST RADAR TRENDS INTO THE HOURLY POP FORECAST THROUGH 15 UTC.
RADAR ECHOES HAVE BEEN STEADILY INCREASING OVER SOUTH CENTRAL ND
DURING THE LAST 90 MINUTES...AND WHILE NO PRECIPITATION REPORTS
HAVE BEEN RECEIVED YET...THE 12 UTC BISMARCK SOUNDING IS NEARLY
SATURATED ALOFT...SO SNOW SHOULD QUICKLY DEVELOP BY MID MORNING.

NOTE THAT OVERNIGHT RAP AND HRRR SIMULATIONS /INCLUDING THE ESRL
HRRR/ HAVE BEEN INCONSISTENT FROM RUN TO RUN AND WITH THE GLOBAL
MODEL GUIDANCE...ESPECIALLY ON THE WESTERN AND SOUTHERN BOUNDARY
OF EXPECTED SNOWFALL TODAY...SO THE ACCUMULATION FORECAST STAYED
THE SAME WITH THIS UPDATE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CST TUE DEC 22 2015

ACCUMULATING SNOW IS THE MAIN CONCERN IN THE SHORT TERM.

CURRENTLY...THE SURFACE LOW WAS AT THE BORDER OF SOUTHEASTERN
MONTANA AND NORTHEASTERN WYOMING. STRONG SOUTHWESTERLY SURFACE
WINDS WERE NOTED OVER EASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA. THESE SURFACE WINDS WERE INDICATIVE OF A STRONG LOW LEVEL
JET DEPICTED IN THE MODELS AT H925 AND H850. AT UPPER LEVELS...A
STRONG SHORTWAVE WAS CENTERED OVER WYOMING. LIGHT RADAR RETURNS
WERE OVER EASTERN MONTANA INTO NORTHEASTERN WYOMING...BUT
INTENSITIES WERE INCREASING SOUTH AND EAST OF BILLINGS INTO
NORTHEASTERN WYOMING...IN THE VICINITY OF THE UPPER LEVEL
SHORTWAVE.

THE UPPER LEVEL SHORTWAVE IS FORECAST TO MOVE NORTHEAST ACROSS THE
DAKOTAS TODAY AND MOVE INTO SOUTHERN MANITOBA TONIGHT. THE SURFACE
AND H700 LOW ARE FORECAST TO TRACK NORTHEASTWARD ACROSS NORTH DAKOTA
TODAY...REACHING THE ND/MN/MANITOBA BORDER BY MIDNIGHT TUESDAY
NIGHT. STRONG FRONTOGENETIC FORCING WITH VERTICAL MOTION IN THE
DENDRITIC GROWTH ZONE ARE EXPECTED ALONG THIS TRACK. THE MODELS
INDICATE A DEEPER DENDRITIC GROWTH ZONE LATE THIS MORNING/AFTERNOON
IN NORTH CENTRAL NORTH DAKOTA. FARTHER SOUTH THE TEMPERATURE
PROFILES ARE WARMER EARLY ON THIS MORNING WHEN THE BEST VERTICAL
MOTION IS FORECAST. SO THE LATEST RUN OF THE MODELS VALIDATE THE
ONGOING FORECAST OF MORE PRECIPITATION/SNOWFALL NORTH CENTRAL VERSUS
ACROSS THE SOUTH. THE WARM AIR LAYER OFF THE SURFACE ASSOCIATED WITH
THE LOW LEVEL JET WILL BRING A CHANCE OF MIXED PRECIPITATION TO
PARTS OF SOUTHERN NORTH DAKOTA TODAY...AND THIS WILL LIMIT THE
AMOUNT OF SNOW EXPECTED IN THE SOUTHERN TIER OF COUNTIES.

THE LATEST SHORT TERM HIGH RESOLUTION MODELS ARE NOT AS ROBUST WITH
PRECIP OUTPUT AS THE GLOBAL MODELS...AND USED A BLEND OF HIGH RES
AND GLOBAL MODEL SNOW RATIO METHODS. SNOW IS EXPECTED TO BEGIN OVER
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AROUND 6 AM CST...AND
INCREASE QUICKLY BY AROUND 9 AM CST. THE GREATEST FORCING MOVES INTO
NORTHERN NORTH DAKOTA AROUND/AFTER 9 AM CST AND THE AFTERNOON HOURS
SHOULD SEE THE MOST SNOW ACCUMULATIONS ACROSS THE NORTH. THE
SOUTHWEST AND SOUTH CENTRAL SHOULD SEE UP TO AN INCH OR 2 OF SNOW BY
TONIGHT...WITH THE GREATEST SNOWFALL OF 3 TO OVER 5 INCHES OF SNOW
IN THE NORTH CENTRAL...WITH THE HIGHER AMOUNTS IN THE TURTLE
MOUNTAINS AREA.

WILL ADD BOTTINEAU COUNTY TO THE ONGOING WINTER WEATHER
ADVISORY...WHICH WILL INCLUDE WESTHOPE AND BOTTINEAU...VELVA AND
TOWNER...AND POINTS EAST TO RUGBY AND THE TURTLE MOUNTAINS. THERE
MAY BE A COUPLE LOCALES THAT REACH 6 INCHES OR A BIT MORE...BUT IN
GENERAL 3 TO 5.5 INCHES OF SNOW IS EXPECTED MOST AREAS IN THE
ADVISORY.

SNOW SHOULD TAPER TO LIGHT SNOW OR FLURRIES AS THE SYSTEM MOVES
NORTHEAST...BUT LINGER THROUGH THE NIGHT TUESDAY NIGHT AS A WEAK
TROWAL FEATURE KEEPS THE WRAP AROUND PRECIPITATION AS FAR WEST AS
MONTANA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM CST TUE DEC 22 2015

COOL AND GENERALLY QUIET WEATHER WILL PREVAIL IN THE LONG TERM.

FLURRIES OR LIGHT SNOW SHOWERS REMAIN POSSIBLE ON WEDNESDAY WITH
LINGERING CYCLONIC FLOW ACROSS THE REGION. ON THE LARGE SCALE...A
BROAD AND LOW-AMPLITUDE 500-MB TROUGH OVER THE WESTERN AND CENTRAL
UNITED STATES WILL BE REPLACED BY A MUCH DEEPER AND DYNAMICALLY-
ENERGIZED TROUGH CENTERED ON THE FOUR-CORNERS REGION BY SATURDAY.
THAT TRANSITION COULD YIELD LIGHT SNOW IN THE NORTHERN PLAINS LATE
ON CHRISTMAS DAY OR MORE SO ON FRIDAY NIGHT AS FLOW ALOFT BECOMES
SOUTHWESTERLY. HOWEVER...CONFIDENCE IN THE NORTHERN EXTENT OF ANY
LIGHT SNOW IS MODEST AT BEST AS SPLIT FLOW TAKES SHAPE ALOFT...AS
EXEMPLIFIED BY THE 00 UTC ECMWF...WHICH WAS A DRY SOLUTION ACROSS
MUCH OF WESTERN AND CENTRAL ND DURING THAT TIME FRAME.

TEMPERATURES WILL BE SEASONABLY COOL MOST OF THE PERIOD...AND WILL
BE COLDEST FRIDAY INTO SATURDAY...WHEN LOWS WILL BE AROUND 0 F AND
HIGHS WILL ONLY BE IN THE TEENS F PER A 00 UTC MULTI-MODEL BLEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 929 AM CST TUE DEC 22 2015

IFR/LIFR CONDITIONS IN SNOW AT KMOT/KJMS DEVELOPING THIS
MORNING...CONTINUING THROUGH THE EARLY AFTERNOON AT KJMS AND
POSSIBLY INTO THE EVENING AT KMOT. IFR CONDITIONS IN LIGHT SNOW
POSSIBLE BY MIDDAY AT KISN WITH A BRIEF LATE AFTERNOON BREAK
POSSIBLE BEFORE ADDITIONAL LIGHT SNOW THIS EVENING AND TONIGHT.
MVFR/IFR CONDITIONS IS STRATUS AT KBIS/KDIK TODAY AND TONIGHT WITH
MUCH LOWER PROBABILITIES FOR SNOW COMPARED TO THE OTHER
TERMINALS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ004-
005-012-013-022-023-025.

&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...CJS
AVIATION...AYD




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 646 AM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 646 AM CST TUE DEC 22 2015

NO SIGNIFICANT CHANGES WITH THIS UPDATE OTHER THAN TO BLEND THE
LATEST RADAR TRENDS INTO THE HOURLY POP FORECAST THROUGH 15 UTC.
RADAR ECHOES HAVE BEEN STEADILY INCREASING OVER SOUTH CENTRAL ND
DURING THE LAST 90 MINUTES...AND WHILE NO PRECIPITATION REPORTS
HAVE BEEN RECEIVED YET...THE 12 UTC BISMARCK SOUNDING IS NEARLY
SATURATED ALOFT...SO SNOW SHOULD QUICKLY DEVELOP BY MID MORNING.

NOTE THAT OVERNIGHT RAP AND HRRR SIMULATIONS /INCLUDING THE ESRL
HRRR/ HAVE BEEN INCONSISTENT FROM RUN TO RUN AND WITH THE GLOBAL
MODEL GUIDANCE...ESPECIALLY ON THE WESTERN AND SOUTHERN BOUNDARY
OF EXPECTED SNOWFALL TODAY...SO THE ACCUMULATION FORECAST STAYED
THE SAME WITH THIS UPDATE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CST TUE DEC 22 2015

ACCUMULATING SNOW IS THE MAIN CONCERN IN THE SHORT TERM.

CURRENTLY...THE SURFACE LOW WAS AT THE BORDER OF SOUTHEASTERN
MONTANA AND NORTHEASTERN WYOMING. STRONG SOUTHWESTERLY SURFACE
WINDS WERE NOTED OVER EASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA. THESE SURFACE WINDS WERE INDICATIVE OF A STRONG LOW LEVEL
JET DEPICTED IN THE MODELS AT H925 AND H850. AT UPPER LEVELS...A
STRONG SHORTWAVE WAS CENTERED OVER WYOMING. LIGHT RADAR RETURNS
WERE OVER EASTERN MONTANA INTO NORTHEASTERN WYOMING...BUT
INTENSITIES WERE INCREASING SOUTH AND EAST OF BILLINGS INTO
NORTHEASTERN WYOMING...IN THE VICINITY OF THE UPPER LEVEL
SHORTWAVE.

THE UPPER LEVEL SHORTWAVE IS FORECAST TO MOVE NORTHEAST ACROSS THE
DAKOTAS TODAY AND MOVE INTO SOUTHERN MANITOBA TONIGHT. THE SURFACE
AND H700 LOW ARE FORECAST TO TRACK NORTHEASTWARD ACROSS NORTH DAKOTA
TODAY...REACHING THE ND/MN/MANITOBA BORDER BY MIDNIGHT TUESDAY
NIGHT. STRONG FRONTOGENETIC FORCING WITH VERTICAL MOTION IN THE
DENDRITIC GROWTH ZONE ARE EXPECTED ALONG THIS TRACK. THE MODELS
INDICATE A DEEPER DENDRITIC GROWTH ZONE LATE THIS MORNING/AFTERNOON
IN NORTH CENTRAL NORTH DAKOTA. FARTHER SOUTH THE TEMPERATURE
PROFILES ARE WARMER EARLY ON THIS MORNING WHEN THE BEST VERTICAL
MOTION IS FORECAST. SO THE LATEST RUN OF THE MODELS VALIDATE THE
ONGOING FORECAST OF MORE PRECIPITATION/SNOWFALL NORTH CENTRAL VERSUS
ACROSS THE SOUTH. THE WARM AIR LAYER OFF THE SURFACE ASSOCIATED WITH
THE LOW LEVEL JET WILL BRING A CHANCE OF MIXED PRECIPITATION TO
PARTS OF SOUTHERN NORTH DAKOTA TODAY...AND THIS WILL LIMIT THE
AMOUNT OF SNOW EXPECTED IN THE SOUTHERN TIER OF COUNTIES.

THE LATEST SHORT TERM HIGH RESOLUTION MODELS ARE NOT AS ROBUST WITH
PRECIP OUTPUT AS THE GLOBAL MODELS...AND USED A BLEND OF HIGH RES
AND GLOBAL MODEL SNOW RATIO METHODS. SNOW IS EXPECTED TO BEGIN OVER
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AROUND 6 AM CST...AND
INCREASE QUICKLY BY AROUND 9 AM CST. THE GREATEST FORCING MOVES INTO
NORTHERN NORTH DAKOTA AROUND/AFTER 9 AM CST AND THE AFTERNOON HOURS
SHOULD SEE THE MOST SNOW ACCUMULATIONS ACROSS THE NORTH. THE
SOUTHWEST AND SOUTH CENTRAL SHOULD SEE UP TO AN INCH OR 2 OF SNOW BY
TONIGHT...WITH THE GREATEST SNOWFALL OF 3 TO OVER 5 INCHES OF SNOW
IN THE NORTH CENTRAL...WITH THE HIGHER AMOUNTS IN THE TURTLE
MOUNTAINS AREA.

WILL ADD BOTTINEAU COUNTY TO THE ONGOING WINTER WEATHER
ADVISORY...WHICH WILL INCLUDE WESTHOPE AND BOTTINEAU...VELVA AND
TOWNER...AND POINTS EAST TO RUGBY AND THE TURTLE MOUNTAINS. THERE
MAY BE A COUPLE LOCALES THAT REACH 6 INCHES OR A BIT MORE...BUT IN
GENERAL 3 TO 5.5 INCHES OF SNOW IS EXPECTED MOST AREAS IN THE
ADVISORY.

SNOW SHOULD TAPER TO LIGHT SNOW OR FLURRIES AS THE SYSTEM MOVES
NORTHEAST...BUT LINGER THROUGH THE NIGHT TUESDAY NIGHT AS A WEAK
TROWAL FEATURE KEEPS THE WRAP AROUND PRECIPITATION AS FAR WEST AS
MONTANA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM CST TUE DEC 22 2015

COOL AND GENERALLY QUIET WEATHER WILL PREVAIL IN THE LONG TERM.

FLURRIES OR LIGHT SNOW SHOWERS REMAIN POSSIBLE ON WEDNESDAY WITH
LINGERING CYCLONIC FLOW ACROSS THE REGION. ON THE LARGE SCALE...A
BROAD AND LOW-AMPLITUDE 500-MB TROUGH OVER THE WESTERN AND CENTRAL
UNITED STATES WILL BE REPLACED BY A MUCH DEEPER AND DYNAMICALLY-
ENERGIZED TROUGH CENTERED ON THE FOUR-CORNERS REGION BY SATURDAY.
THAT TRANSITION COULD YIELD LIGHT SNOW IN THE NORTHERN PLAINS LATE
ON CHRISTMAS DAY OR MORESO ON FRIDAY NIGHT AS FLOW ALOFT BECOMES
SOUTHWESTERLY. HOWEVER...CONFIDENCE IN THE NORTHERN EXTENT OF ANY
LIGHT SNOW IS MODEST AT BEST AS SPLIT FLOW TAKES SHAPE ALOFT...AS
EXEMPLIFIED BY THE 00 UTC ECMWF...WHICH WAS A DRY SOLUTION ACROSS
MUCH OF WESTERN AND CENTRAL ND DURING THAT TIME FRAME.

TEMPERATURES WILL BE SEASONABLY COOL MOST OF THE PERIOD...AND WILL
BE COLDEST FRIDAY INTO SATURDAY...WHEN LOWS WILL BE AROUND 0 F AND
HIGHS WILL ONLY BE IN THE TEENS F PER A 00 UTC MULTI-MODEL BLEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM CST TUE DEC 22 2015

AREAS OF MVFR-IFR STRATUS EXPECTED IN CENTRAL NORTH DAKOTA EARLY
THIS MORNING AT KJMS. VFR CONDITIONS WEST AT KISN/KMOT/KDIK/BIS
EARLY...THEN INCREASING CLOUDS WITH AN APPROACHING SMALL BUT POTENT
LOW PRESSURE SYSTEM. THIS SYSTEM WILL BRING MVFR-IFR CEILINGS AND
VISIBILITIES IN SNOW AND FOG FROM MAINLY KDIK AND KBIS AROUND 12Z TO
KMOT AND KJMS BEGINNING AROUND 15Z. THE SYSTEM WILL EXIT SLOWLY TO
THE NORTHEAST TUESDAY EVENING...BUT THE POTENTIAL FOR LOW STRATUS
AND FOG WILL REMAIN AT TAF SITES.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ004-
005-012-013-022-023-025.

&&

$$

UPDATE...CJS
SHORT TERM...JV
LONG TERM...CJS
AVIATION...JV




AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 527 AM CST TUE DEC 22 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM CST TUE DEC 22 2015

THE AREA CONTINUES TO BE SOCKED IN WITH LOW CLOUDS AND FOG VERY
EARLY THIS MORNING. THE MAIN CHALLENGE TODAY WILL BE HOW QUICKLY THE
FOG MIXES OUT AND HOW LONG LOWER CLOUDS WILL LINGER ACROSS THE AREA.
A DEEPENING AREA OF LOW PRESSURE PRESENTLY SITUATED OVER THE
NORTHERN ROCKIES IS EXPECTED TO SLIDE INTO WESTERN SOUTH DAKOTA BY
MID MORNING...THEN TRACK INTO EASTERN NORTH DAKOTA BY THIS EVENING.
OUT AHEAD OF THIS SYSTEM...SOUTHERLY WINDS WILL INCREASE ACROSS OUR
AREA THROUGH THE DAY AS THE GRADIENT TIGHTENS...AND WITH THAT EXPECT
TO SEE IMPROVING VISIBILITIES THROUGH THE MORNING INTO EARLY
AFTERNOON. THE RAP SEEMS TO BE HANDLING THE CURRENT BOUNDARY LAYER
MOISTURE THE BEST...AND WOULD INDICATE THAT LOW CLOUDS WILL ERODE
FROM THE SOUTHWEST DURING THE LATER MORNING AND AFTERNOON AS
SOUTH/SOUTHWEST MIXED LAYER WINDS INCREASE.  EVEN SO...WILL PROBABLY
REMAIN MOSTLY CLOUDY AS MID AND HIGH CLOUDS INCREASE ACROSS THE
REGION. WITH THE STRONG SOUTHERLY FLOW TODAY...WILL SEE TEMPERATURES
RESPOND ACCORDINGLY...WITH HIGHS A GOOD 15 DEGREES WARMER THAN
YESTERDAY. THIS WILL PLAY OUT TO AFTERNOON TEMPERATURES IN THE UPPER
30S TO LOWER 40S.

FOR TONIGHT...A SHORTWAVE LIFTS FROM SOUTHEASTERN NEBRASKA INTO
IOWA/SOUTHEASTERN MINNESOTA OVERNIGHT ON A SOUTHWESTERLY UPPER LEVEL
FLOW. WHILE THE MAIN ENERGY WILL PASS TO THE EAST OF OUR
CWA...MODELS ARE IN DECENT AGREEMENT WITH POSSIBLY GRAZING PORTIONS
OF OUR NORTHWESTERN IOWA/SOUTHWESTERN MINNESOTA ZONES WITH LIGHT
PRECIPITATION LATER TONIGHT. ALL MODELS ARE INDICATING PLUS 0 C 850
MB TEMPERATURES OVER THAT AREA DURING THAT TIME FRAME...SO
PRECIPITATION TYPE COMES DOWN TO SURFACE TEMPERATURES. PRESENTLY AM
FORECASTING SURFACE TEMPERATURES SLOWLY FALLING INTO THE LOWER 30S
VERY LATE TONIGHT...SO IF PRECIPITATION DEVELOPS CANNOT RULE OUT A
PERIOD OF FREEZING RAIN OVER THAT AREA. IT WILL BE A CLOSE CALL WITH
SURFACE TEMPERATURES JUST HOVERING AROUND THE FREEZING MARK...AND
WITH ONLY LIGHT QPF AM NOT EXPECTING ANY SIGNIFICANT IMPACTS AT THIS
POINT...BUT WILL BE SOMETHING TO KEEP AN EYE ON. IT WILL BE COOLER
BACK TO THE WEST HOWEVER AS A COLD FRONT BEGINS TO SLIDE INTO OUR
WESTERN CWA TOWARD MORNING...WITH LOWS RUNNING FROM NEAR 20 FROM
SOUTH CENTRAL SD THROUGH EAST CENTRAL SD...TO LOWER 30S THROUGH
NORTHWEST IA AS REFERRED TO ABOVE.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 416 AM CST TUE DEC 22 2015

AN UPPER LEVEL TROUGH LIFTS THROUGH NORTH DAKOTA WEDNESDAY
MORNING WHILE A OVER IOWA. MOISTURE DOES SURGE A LITTLE NORTHWARD IN
THE MORNING AHEAD OF AN ADVANCING COLD FRONT. MODELS A BIT MORE
AGGRESSIVE IN BRINGING SOME LIGHT POPS ACROSS OUR FAR SOUTHEAST
CORNER WHERE MOISTURE APPEARS TO BE DEEPER. DID BUMP UP POPS
SLIGHTLY AND EXPANDED THEM SLIGHTLY WEST OF PREVIOUS FORECASTS GIVEN
THE MORE WESTWARD MODEL TRENDS. PRECIPITATION TYPE IS LESS
CERTAIN...WITH FAIRLY WARM MID AND LOW LEVEL TEMPERATURES...WHILE
COLD AIR BEGINS TO SPREAD EAST AT THE SURFACE. THINK THAT MODELS MAY
BE A TOUCH TOO COLD AT THE SURFACE WHERE THE PRECIPITATION IS
EXPECTED...WITH READINGS RIGHT AROUND FREEZING. EXPECT TYPE TO BE
MAINLY LIGHT RAIN OR POSSIBLY VERY BRIEF FREEZING RAIN NEAR DAYBREAK
IF SURFACE TEMPERATURES COOL ENOUGH. THE PRECIPITATION SHOULD EXIT
THE FORECAST AREA TO THE EAST BY MID-AFTERNOON...AND WITH
TEMPERATURES WARMING BACK ABOVE FREEZING...ANY SLIPPERY SURFACES
FROM -FZRA WILL IMPROVE QUICKLY. WINDS WILL TURN BREEZY FROM THE
NORTHWEST WITH DECENT MIXING BEHIND THE FRONT DURING THE DAY...WHICH
WILL RESULT IN HIGHS IN THE UPPER 20S TO UPPER 30S.

ZONAL FLOW ON THURSDAY WILL SPELL A DRY AND SEASONALLY MILD DAY
ACROSS THE REGION. LIGHT WESTERLY WINDS WEDNESDAY NIGHT WILL TURN
SOUTHWESTERLY ON THURSDAY...AND HELP SCOUR OUT THE PERSISTENT CLOUD
COVERAGE FROM WEST TO EAST AS THE DAY PROGRESSES. TEMPERATURES WILL
BE SIMILAR TO WEDNESDAY WITH HIGHS IN THE UPPER 20S TO UPPER 30S.

CONFIDENCE IS INCREASING WITH THE POTENTIAL FOR SOME LIGHT
PRECIPITATION DEVELOPING FRIDAY INTO SATURDAY. WHILE THERE ARE
SOME TIMING CONCERNS BETWEEN THE MODELS...THEY ARE ALL HINTING AT
A GOOD POTENTIAL FOR SOME STEADY LIGHT TO MODERATE PRECIPITATION
DURING THIS PERIOD. THE GEM IS THE QUICKEST WITH LIFTING A WAVE
NORTHEAST FROM THE CENTRAL ROCKIES INTO THE MID MISSOURI VALLEY AS
EARLY AS LATE FRIDAY MORNING. THE ECMWF LAGS BY NEAR 12
HOURS...WHILE THE GFS IS BETWEEN THE TWO SOLUTIONS. ALL MODELS
BRING A DECENT AMOUNT OF QPF THROUGH THE CWA...HIGHEST WEST OF THE
JAMES RIVER AND NORTH OF I90 - OVER A HALF INCH -OVERNIGHT FRIDAY.
IN THIS AREA...TEMPS WILL BE COLD ENOUGH PRIMARILY FOR
SNOWFALL...WHILE AREAS SOUTH AND EAST MAY SEE MORE OF A MIX. STILL
A LOT OF UNCERTAINTY TO IRON OUT IN FUTURE RUNS...BUT IT WILL BE
SOMETHING TO WATCH CLOSELY.

LESS CONFIDENCE LIES BEYOND SATURDAY...AS THE FOCUS BECOMES THE
PROGRESSION OF A SLOW MOVING UPPER LEVEL LOW WOBBLING TOWARDS THE
RIO GRANDE AREA OF TEXAS ON SUNDAY. ACCORDING TO THE GFS...THIS
LARGE SYSTEM WILL LIFT NORTH NORTHEAST...BECOMING CENTERED OVER THE
KANSAS CITY AREA MONDAY MORNING THEN RAPIDLY HEADS INTO CENTRAL
WISCONSIN MONDAY EVENING. THIS PROGRESSION SEEMS TOO MUCH TOO
BULLISH. THE ECMWF MEANWHILE DOES NOT REACH THE KC AREA UNTIL
TUESDAY MORNING. SUFFICE TO SAY...CONFIDENCE IS LOW...SO JUST RAN
WITH THE ALL BLEND POPS FOR NOW. BOTH SOLUTIONS HOWEVER DO INDICATE
A PRETTY BIG IMPACT FOR OUR AREA WITH THIS STORM SYSTEM.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 522 AM CST TUE DEC 22 2015

WIDESPREAD IFR/MVFR CONDITIONS THIS MORNING ARE EXPECTED TO
IMPROVE BY LATE MORNING AND EARLY AFTERNOON AS SOUTHERLY WINDS
PICK UP ACROSS THE AREA. WINDS WILL THEN GUST IN EXCESS OF 25 KTS
INTO THE LATE AFTERNOON. WINDS WILL THEN DROP OFF THIS
EVENING...WITH CONDITIONS DETERIORATING IN EASTERN AREAS LATER
TONIGHT AS STRATUS RETURNS AND VISIBILITIES LOWER INTO THE MVFR
RANGE.

&&

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

$$

SHORT TERM...JM
LONG TERM...
AVIATION...JM



AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 418 AM CST TUE DEC 22 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM CST TUE DEC 22 2015

THE AREA CONTINUES TO BE SOCKED IN WITH LOW CLOUDS AND FOG VERY
EARLY THIS MORNING. THE MAIN CHALLENGE TODAY WILL BE HOW QUICKLY THE
FOG MIXES OUT AND HOW LONG LOWER CLOUDS WILL LINGER ACROSS THE AREA.
A DEEPENING AREA OF LOW PRESSURE PRESENTLY SITUATED OVER THE
NORTHERN ROCKIES IS EXPECTED TO SLIDE INTO WESTERN SOUTH DAKOTA BY
MID MORNING...THEN TRACK INTO EASTERN NORTH DAKOTA BY THIS EVENING.
OUT AHEAD OF THIS SYSTEM...SOUTHERLY WINDS WILL INCREASE ACROSS OUR
AREA THROUGH THE DAY AS THE GRADIENT TIGHTENS...AND WITH THAT EXPECT
TO SEE IMPROVING VISIBILITIES THROUGH THE MORNING INTO EARLY
AFTERNOON. THE RAP SEEMS TO BE HANDLING THE CURRENT BOUNDARY LAYER
MOISTURE THE BEST...AND WOULD INDICATE THAT LOW CLOUDS WILL ERODE
FROM THE SOUTHWEST DURING THE LATER MORNING AND AFTERNOON AS
SOUTH/SOUTHWEST MIXED LAYER WINDS INCREASE.  EVEN SO...WILL PROBABLY
REMAIN MOSTLY CLOUDY AS MID AND HIGH CLOUDS INCREASE ACROSS THE
REGION. WITH THE STRONG SOUTHERLY FLOW TODAY...WILL SEE TEMPERATURES
RESPOND ACCORDINGLY...WITH HIGHS A GOOD 15 DEGREES WARMER THAN
YESTERDAY. THIS WILL PLAY OUT TO AFTERNOON TEMPERATURES IN THE UPPER
30S TO LOWER 40S.

FOR TONIGHT...A SHORTWAVE LIFTS FROM SOUTHEASTERN NEBRASKA INTO
IOWA/SOUTHEASTERN MINNESOTA OVERNIGHT ON A SOUTHWESTERLY UPPER LEVEL
FLOW. WHILE THE MAIN ENERGY WILL PASS TO THE EAST OF OUR
CWA...MODELS ARE IN DECENT AGREEMENT WITH POSSIBLY GRAZING PORTIONS
OF OUR NORTHWESTERN IOWA/SOUTHWESTERN MINNESOTA ZONES WITH LIGHT
PRECIPITATION LATER TONIGHT. ALL MODELS ARE INDICATING PLUS 0 C 850
MB TEMPERATURES OVER THAT AREA DURING THAT TIME FRAME...SO
PRECIPITATION TYPE COMES DOWN TO SURFACE TEMPERATURES. PRESENTLY AM
FORECASTING SURFACE TEMPERATURES SLOWLY FALLING INTO THE LOWER 30S
VERY LATE TONIGHT...SO IF PRECIPITATION DEVELOPS CANNOT RULE OUT A
PERIOD OF FREEZING RAIN OVER THAT AREA. IT WILL BE A CLOSE CALL WITH
SURFACE TEMPERATURES JUST HOVERING AROUND THE FREEZING MARK...AND
WITH ONLY LIGHT QPF AM NOT EXPECTING ANY SIGNIFICANT IMPACTS AT THIS
POINT...BUT WILL BE SOMETHING TO KEEP AN EYE ON. IT WILL BE COOLER
BACK TO THE WEST HOWEVER AS A COLD FRONT BEGINS TO SLIDE INTO OUR
WESTERN CWA TOWARD MORNING...WITH LOWS RUNNING FROM NEAR 20 FROM
SOUTH CENTRAL SD THROUGH EAST CENTRAL SD...TO LOWER 30S THROUGH
NORTHWEST IA AS REFERRED TO ABOVE.


.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 416 AM CST TUE DEC 22 2015

AN UPPER LEVEL TROUGH LIFTS THROUGH NORTH DAKOTA WEDNESDAY
MORNING WHILE A OVER IOWA. MOISTURE DOES SURGE A LITTLE NORTHWARD IN
THE MORNING AHEAD OF AN ADVANCING COLD FRONT. MODELS A BIT MORE
AGGRESSIVE IN BRINGING SOME LIGHT POPS ACROSS OUR FAR SOUTHEAST
CORNER WHERE MOISTURE APPEARS TO BE DEEPER. DID BUMP UP POPS
SLIGHTLY AND EXPANDED THEM SLIGHTLY WEST OF PREVIOUS FORECASTS GIVEN
THE MORE WESTWARD MODEL TRENDS. PRECIPITATION TYPE IS LESS
CERTAIN...WITH FAIRLY WARM MID AND LOW LEVEL TEMPERATURES...WHILE
COLD AIR BEGINS TO SPREAD EAST AT THE SURFACE. THINK THAT MODELS MAY
BE A TOUCH TOO COLD AT THE SURFACE WHERE THE PRECIPITATION IS
EXPECTED...WITH READINGS RIGHT AROUND FREEZING. EXPECT TYPE TO BE
MAINLY LIGHT RAIN OR POSSIBLY VERY BRIEF FREEZING RAIN NEAR DAYBREAK
IF SURFACE TEMPERATURES COOL ENOUGH. THE PRECIPITATION SHOULD EXIT
THE FORECAST AREA TO THE EAST BY MID-AFTERNOON...AND WITH
TEMPERATURES WARMING BACK ABOVE FREEZING...ANY SLIPPERY SURFACES
FROM -FZRA WILL IMPROVE QUICKLY. WINDS WILL TURN BREEZY FROM THE
NORTHWEST WITH DECENT MIXING BEHIND THE FRONT DURING THE DAY...WHICH
WILL RESULT IN HIGHS IN THE UPPER 20S TO UPPER 30S.

ZONAL FLOW ON THURSDAY WILL SPELL A DRY AND SEASONALLY MILD DAY
ACROSS THE REGION. LIGHT WESTERLY WINDS WEDNESDAY NIGHT WILL TURN
SOUTHWESTERLY ON THURSDAY...AND HELP SCOUR OUT THE PERSISTENT CLOUD
COVERAGE FROM WEST TO EAST AS THE DAY PROGRESSES. TEMPERATURES WILL
BE SIMILAR TO WEDNESDAY WITH HIGHS IN THE UPPER 20S TO UPPER 30S.

CONFIDENCE IS INCREASING WITH THE POTENTIAL FOR SOME LIGHT
PRECIPITATION DEVELOPING FRIDAY INTO SATURDAY. WHILE THERE ARE
SOME TIMING CONCERNS BETWEEN THE MODELS...THEY ARE ALL HINTING AT
A GOOD POTENTIAL FOR SOME STEADY LIGHT TO MODERATE PRECIPITATION
DURING THIS PERIOD. THE GEM IS THE QUICKEST WITH LIFTING A WAVE
NORTHEAST FROM THE CENTRAL ROCKIES INTO THE MID MISSOURI VALLEY AS
EARLY AS LATE FRIDAY MORNING. THE ECMWF LAGS BY NEAR 12
HOURS...WHILE THE GFS IS BETWEEN THE TWO SOLUTIONS. ALL MODELS
BRING A DECENT AMOUNT OF QPF THROUGH THE CWA...HIGHEST WEST OF THE
JAMES RIVER AND NORTH OF I90 - OVER A HALF INCH -OVERNIGHT FRIDAY.
IN THIS AREA...TEMPS WILL BE COLD ENOUGH PRIMARILY FOR
SNOWFALL...WHILE AREAS SOUTH AND EAST MAY SEE MORE OF A MIX. STILL
A LOT OF UNCERTAINTY TO IRON OUT IN FUTURE RUNS...BUT IT WILL BE
SOMETHING TO WATCH CLOSELY.

LESS CONFIDENCE LIES BEYOND SATURDAY...AS THE FOCUS BECOMES THE
PROGRESSION OF A SLOW MOVING UPPER LEVEL LOW WOBBLING TOWARDS THE
RIO GRANDE AREA OF TEXAS ON SUNDAY. ACCORDING TO THE GFS...THIS
LARGE SYSTEM WILL LIFT NORTH NORTHEAST...BECOMING CENTERED OVER THE
KANSAS CITY AREA MONDAY MORNING THEN RAPIDLY HEADS INTO CENTRAL
WISCONSIN MONDAY EVENING. THIS PROGRESSION SEEMS TOO MUCH TOO
BULLISH. THE ECMWF MEANWHILE DOES NOT REACH THE KC AREA UNTIL
TUESDAY MORNING. SUFFICE TO SAY...CONFIDENCE IS LOW...SO JUST RAN
WITH THE ALL BLEND POPS FOR NOW. BOTH SOLUTIONS HOWEVER DO INDICATE
A PRETTY BIG IMPACT FOR OUR AREA WITH THIS STORM SYSTEM.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1044 PM CST MON DEC 21 2015

CERTAINLY NO SHORTAGE OF IFR TO LIFR CONDITIONS ACROSS THE
FORECAST AREA AT THIS TIME. BELIEVE STRONGLY THAT THIS SITUATION
WILL PREVAIL FOR THE NEXT SEVERAL HOURS. HOWEVER LATE TONIGHT...
THE LOW LEVEL WINDS INCLUDING SURFACE WINDS INCREASE DRAMATICALLY
IN ADVANCE OF THE NEXT SHORT WAVE WHICH MOVES ACROSS THE AREA
TUESDAY MORNING. AS THE WINDS INCREASE FROM THE SOUTH AND
SOUTHEAST...IT IS ANTICIPATED THAT THE VISIBILITY WILL IMPROVE
TOWARD TUESDAY MORNING...BUT THE LOW STRATUS WILL LINGER. INCLUDED
THIS SCENARIO IN THE TAF SITES...ESPECIALLY AT KFSD WHERE THICKER
FOG HAS SET IN.

FURTHER OUT...THE NAM HUMIDITY TIME SECTIONS AND SOUNDINGS
CONTINUE TO SHOW A NEVER ENDING REGIME OF LOW CLOUDS THROUGH THE
DAY TUESDAY. THE ONE EXCEPTION IS AT KSUX WHERE IT SHOWS SOME
CLEARING. THE GFS ON THE OTHER HAND VIRTUALLY SHOWS NO LOW CLOUDS
WITH ITS FORECAST WHICH OBVIOUSLY IS NOT LINING UP WITH REALITY.
WHAT LOOKED THE BEST WAS THE LATEST RAP. THE RAP SHOWS CLEARING IN
THE LOW LAYERS LATE TUESDAY MORNING AND EARLY AFTERNOON WHICH
STANDS TO REASON AS YOU DO NOT HAVE TO GO VERY DEEP INTO NEBRASKA
TO FIND NO STRATUS. SO ONCE THE WINDS SHIFT TO THE SOUTH AS
TONIGHT PROGRESSES...ONE WOULD THINK THAT THE FORECAST AREA WILL
GO VFR TOWARD THE MIDDLE OF THE DAY ON TUESDAY.


&&

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

$$

SHORT TERM...JM
LONG TERM...
AVIATION...MJ




AREA FORECAST DISCUSSION

NWS NASHVILLE TN

 556 AM CST TUE DEC 22 2015

.DISCUSSION...

...UNUSUAL LATE DECEMBER SEVERE WEATHER OUTBREAK POSSIBLE ON
WEDNESDAY INTO WEDNESDAY NIGHT...

LATEST SURFACE OBSERVATIONS SHOW UNUSUALLY MILD AND HUMID
CONDITIONS ACROSS THE MID STATE WITH TEMPERATURES AND DEWPOINTS
IN THE MID 50S TO LOW 60S. RADAR SHOWS WIDESPREAD SHOWERS AND A
COUPLE OF THUNDERSTORMS CONTINUE OVER MAINLY THE NORTHWEST HALF
OF THE CWA ATTM. LATEST HRRR RUNS INDICATE MOST OF THIS ACTIVITY
WILL SHIFT NORTHEAST OF THE CWA BY 12Z...WITH ONLY ISOLATED
SHOWERS POSSIBLE THE REST OF TODAY MAINLY ACROSS THE SOUTH.
STRONG WAA WILL CONTINUE TO PUMP GULF MOISTURE INTO THE
AREA TODAY...WITH TEMPERATURES RISING WELL INTO THE 60S BY THIS
AFTERNOON. BY THIS EVENING....00Z MODELS PROG A SMALL H5 SHORTWAVE
TO MOVE FROM THE GULF COAST TOWARDS EAST TN...BRINGING THE NEXT
ROUND OF SHOWERS AND STORMS MAINLY TO THE SOUTHEAST HALF OF THE
CWA TUESDAY NIGHT.

SEVERE THUNDERSTORMS ARE BECOMING INCREASINGLY LIKELY ON
WEDNESDAY INTO WEDNESDAY NIGHT AS 00Z GFS/ECMWF NOW IN GOOD
AGREEMENT TAKING A LARGE H5 NEGATIVELY TILTED TROUGH INTO THE
LOWER MISSISSIPPI AND TENNESSEE VALLEYS DURING THE DAY. SOME
MODELS INCLUDING THE 00Z NMMB DEVELOP CONVECTION ACROSS MS/AL
THAT MOVES RAPIDLY ACROSS EASTERN MIDDLE TENNESSEE BY LATE
MORNING...AND SHOULD THIS OCCUR SOME OF THESE STORMS COULD BE
STRONG OR EVEN SEVERE AS EFFECTIVE CAPE INCREASES UP TO 500 J/KG
AND SFC-6KM SHEAR RISES TO 60 KTS BY 18Z. HOWEVER...MAIN SEVERE
THUNDERSTORM POTENTIAL APPEARS TO BE WEDNESDAY AFTERNOON INTO
WEDNESDAY EVENING AS SFC COLD FRONT PUSHES TOWARDS THE MID STATE
FROM THE WEST. SEVERAL MODELS INCLUDING THE 00Z/06Z NAM...00Z
GFS...AND OTHERS ALL SUGGEST CELLULAR CONVECTION...INCLUDING
POTENTIAL SUPERCELLS...WILL DEVELOP ACROSS MS/WEST TN THEN SPREAD
VERY RAPIDLY NORTHEAST AT UP TO 55 KTS ACROSS THE CWA INTO
WEDNESDAY EVENING. SFC TEMPS IN THE 70S WITH DEWPOINTS WELL INTO
THE 60S...CAPES RISING INTO A SEASONABLY HIGH 500-1000 J/KG
RANGE...AND SFC-6KM SHEAR INCREASING TO 70-75KTS BETWEEN 23/18Z
AND 24/06Z ALL SUGGEST LIKELIHOOD FOR SEVERE THUNDERSTORMS DURING
THIS TIMEFRAME. OF NOTABLE CONCERN...SHARPPY 00Z GFS SOUNDINGS
SHOW FAVORABLE CONDITIONS FOR COOL-SEASON TORNADOES WITH A VERY
MOIST BOUNDARY LAYER...SFC-1KM SRH AROUND 400 M2/S2...AND LCLS
BELOW 1000M. SPC HAS ACCORDINGLY BUMPED UP OUR SEVERE RISK INTO
THE ENHANCED CATEGORY FOR WEDNESDAY/WEDNESDAY NIGHT. MAIN NEGATIVE
FACTORS FOR A SEVERE WEATHER OUTBREAK ACROSS OUR CWA ARE THE
HIGHEST INSTABILITY REMAINING TO OUR WEST/SOUTHWEST...UNFAVORABLE
SURFACE LOW PLACEMENT WELL TO OUR NORTH IN THE GREAT
LAKES/CANADA...AND CLIMATOLOGY SHOWING DECEMBER AS THE LEAST
LIKELY MONTH FOR TORNADOES ACROSS MIDDLE TENNESSEE.

AFTER SHOWERS AND STORMS EXIT THE MID STATE EARLY
THURSDAY...APPEARS FORECAST AREA WILL BE MOSTLY DRY DURING THE
DAY WITH TEMPERATURES WARMING WELL INTO THE 70S. THIS DRY PERIOD
WILL BE SHORT LIVED AS WARM FRONT RETURNS NORTHWARD THURSDAY
NIGHT AND ESPECIALLY CHRISTMAS DAY BRINGING YET ANOTHER ROUND OF
WIDESPREAD SHOWERS AND THUNDERSTORMS. VERY WARM AND HUMID
CONDITIONS ARE THEN EXPECTED OVER THE WEEKEND WITH TEMPERATURES IN
THE 70S AND DEWPOINTS IN THE 60S...ALTHOUGH POPS WILL BE LOW WITH
MAINLY JUST ISOLATED SHOWERS ANTICIPATED. GFS/ECMWF CONTINUE TO
STRUGGLE WITH EVOLUTION OF MAIN UPPER TROUGH/CLOSED H5 LOW OVER
THE WESTERN CONUS...WITH ECMWF NEARLY 24 HOURS SLOWER THAN THE GFS
EJECTING SYSTEM EASTWARD. HOWEVER...THIS IS A KNOWN BIAS OF THE
ECMWF...AND LEANED MORE TOWARDS THE GFS WITH HIGHEST POPS ON
MONDAY INTO MONDAY NIGHT AS STRONG COLD FRONT BRINGS ANOTHER ROUND
OF WIDESPREAD SHOWERS AND POTENTIALLY STRONG THUNDERSTORMS TO THE
MID STATE IN THIS VERY UNUSUAL LATE DECEMBER WEATHER PATTERN.

&&

.AVIATION...
12Z TAF DISCUSSION.

POOR FLYING CONDITIONS NEXT 24 HOURS AND BEYOND DUE TO LOW
CEILINGS AND VISIBILITIES. CURRENTLY EXITING SHORT WAVE AXIS
EXTENDS DOWN THROUGH MIDDLE TENNESSEE WITH SHOWER ACTIVITY PUSHING
EAST AND WILL SCATTERED OUT BEFORE PULLING OFF PLATEAU AROUND
15Z-16Z. STILL LOOKING FOR GENERALLY LOW CEILINGS AND FOG DURING
THE DAY...MAY IMPROVE SOME BUT NOT FOR LONG. RAIN MOVES IN AGAIN
TONIGHT WITH A FEW THUNDERSTORMS...ESPECIALLY AFTER MIDNIGHT.

&&

.CLIMATE...

AS FAR AS SEVERE WEATHER CLIMATOLOGY GOES...DECEMBER IS THE LEAST
LIKELY MONTH FOR TORNADOES IN MIDDLE TENNESSEE...WITH ONLY 7 ON
RECORD /INCLUDING 1 IN LINCOLN COUNTY/ SINCE THE EARLY 1800S. THE
LAST TORNADO IN MIDDLE TENNESSEE DURING THE MONTH OF DECEMBER
OCCURRED ON DECEMBER 16 2000 WHEN THE AFOREMENTIONED TORNADO HIT
LINCOLN COUNTY. IN THE OHX CWA...THE LAST DECEMBER TORNADO ON
RECORD OCCURRED IN WILLIAMSON COUNTY ON DECEMBER 24 1988.

THE UNUSUALLY WARM WEATHER OVER THE NEXT SEVERAL DAYS WILL LIKELY
SET SOME RECORDS. WILL SEND OUT A PNS LISTING ALL OF THE RECORD
HIGHS AND RECORD WARM MINIMUM TEMPERATURES FOR NASHVILLE AND
CROSSVILLE LATER THIS MORNING.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SHORT TERM/AVIATION........01/BOYD
LONG TERM..................55/SHAMBURGER




AREA FORECAST DISCUSSION

NWS HOUSTON/GALVESTON TX

 533 AM CST TUE DEC 22 2015

.AVIATION...
LOW CIGS AND VISIBILITIES WILL PREVAIL THIS MORNING. MAINLY
LIFR/VLIFR THROUGH 16-17Z. STRONGER SFC WINDS SHOULD ALLOW FOR
SOME MIXING OF DRIER AIR ALOFT TOWARD THE SFC BUT A STUBBORN TEMP
INVERSION WILL WORK AGAINST MIXING. IF ENOUGH DRY AIR CAN MIX
DOWN...VFR CONDS POSSIBLE FOR A BRIEF WINDOW THIS AFTN. LEANED
TOWARD A HRRR/NAM/GFS BLEND FOR THIS TAF PACKAGE WITH
SIGNIFICANTLY MORE WEIGHT GIVEN TO THE HRRR VSBY/CIGS. A
WEAK UPPER LEVEL TROUGH WILL MOVE THROUGH THE REGION TONIGHT AND
THIS FEATURE SHOULD PROVIDE ENOUGH LIFT TO INITIATE A FEW SHOWERS.
WILL CARRY A VCSH AFTER 03Z FOR ALL TAF SITES. SEA FOG WILL PLAGUE
KGLS AS WELL AND ANY IMPROVEMENT IN VSBY/CIGS DURING THE DAY WILL
BE SHORT LIVED. CONDS REMAIN FAVORABLE FOR SEA FOG THROUGH THE END
OF THE WEEK. 43

&&

.PREV DISCUSSION... /ISSUED 447 AM CST TUE DEC 22 2015/

DISCUSSION...
EARLY MORNING OBSERVATIONS AROUND SOUTHEAST TEXAS SHOW NEAR ZERO
VISIBILITIES FROM DENSE FOG... AND THESE CONDITIONS ARE EXPECTED
TO CONTINUE THROUGH MUCH OF THE MORNING. HAVE EXTENDED THE DENSE
FOG ADVISORY THROUGH 10 AM CST BUT CONCERNED THAT THIS MAY NEED TO
BE EXTENDED WITH THE MORNING UPDATE. HRRR VISIBILITY TRENDS SHOW
FOG LINGERING INTO LATE MORNING... AND THIS SOLUTION MAKES SOME
SENSE WITH FORECAST SOUNDINGS SHOWING A STOUT MORNING INVERSION
ALSO PERSISTING INTO LATE MORNING. THIS WOULD DELAY THE ONSET OF
DAYTIME MIXING AND ALLOW FOG TO HOLD ON A BIT LONGER THAN
ANTICIPATED.

FOR THE REMAINDER OF THE DAY... MESSY SOUTHWEST FLOW WILL CONTINUE
ALOFT WITH LARGE SCALE TROUGHING IN PLACE ACROSS THE WESTERN
CONUS. EARLY MORNING WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
LOCATED OVER THE MEXICAN STATE OF COAHUILA EMBEDDED IN THE FLOW
ALOFT WITH REGIONAL RADAR MOSAIC SHOWING SHOWERS WITH EMBEDDED
THUNDERSTORMS STREAMING ACROSS THE NORTHWESTERN GULF. AS THE
SHORTWAVE OVER MEXICO MOVES TOWARDS THE REGION THIS MORNING...
EXPECT SHOWER AND THUNDERSTORM COVERAGE TO EXPAND NORTHWARD INTO
SOUTHEAST TEXAS. THE ACTUAL TRAJECTORY OF THIS WAVE WILL PLAY A
BIG ROLE IN HOW FAR NORTH RAIN WILL EXTEND INLAND TODAY... AND FOR
NOW ONLY HIGHLIGHTING 20 TO 30 POPS WITH GREATEST COVERAGE
EXPECTED ALONG AND SOUTH OF INTERSTATE 10.

FOR THIS EVENING AND TONIGHT... EXPECT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO DEVELOP ACROSS THE REGION. AS A SHORTWAVE
TROUGH SWINGS ACROSS THE SOUTHERN PLAINS THIS EVENING...
INCREASING FORCING FOR ASCENT WILL OVERSPREAD THE EASTERN HALF OF
THE STATE WITH ISOLATED TO SCATTERED SHOWERS AND POSSIBLY
THUNDERSTORMS BLOSSOMING IN RESPONSE. HIGHLIGHTING GREATEST
CHANCES /40 TO 50 POPS/ OVER THE NORTHERN AND NORTHEASTERN
COUNTIES CLOSER TO THE PASSING TROUGH. SPC IS CURRENTLY
HIGHLIGHTING THESE AREAS WITH A MARGINAL RISK FOR SEVERE
THUNDERSTORMS. FORECAST SOUNDINGS AT COLLEGE STATION AND LUFKIN DO
ADVERTISE MID LEVEL LAPSE RATES AROUND 6-7 KM/C... MLCAPE VALUES
EXCEEDING 1000 J/KG OVERNIGHT... AND 0-6 KM SHEAR VALUES AROUND 40
TO 50 KNOTS. GIVEN THIS... CANNOT RULE OUT AN ISOLATED STRONGER TO
POSSIBLY SEVERE STORM OVER THE NORTHERN AND NORTHEASTERN COUNTIES.
HOWEVER... THESE STORMS WOULD BE THE EXCEPTION AND NOT THE RULE
DUE TO SOME UNCERTAINTY IN ACTUAL THUNDERSTORM COVERAGE.

AS THE SOUTHERN PLAINS SHORTWAVE LIFTS NORTHEAST... IT WILL SEND
A WEAK FRONTAL BOUNDARY INTO THE REGION DURING THE DAY ON
WEDNESDAY. EXPECT LINGERING SHOWERS AND THUNDERSTORMS AHEAD OF THE
BOUNDARY ON WEDNESDAY MORNING. HOWEVER... INCREASINGLY SOUTHWEST
FLOW ABOVE THE SURFACE AS THE TROUGH DEPARTS WILL ADVECT DRIER AIR
OVER THE REGION AND THIS WILL RESULT IN A BRIEF RESPITE IN RAIN
CHANCES WEDNESDAY AFTERNOON THROUGH CHRISTMAS EVE MORNING. HOW
FAR INTO THE REGION THE BOUNDARY WILL MOVE IS STILL A LITTLE
UNCERTAIN... WITH 700 MB FLOW BECOMING INCREASINGLY PARALLEL TO
THE BOUNDARY /LIMITING SUPPORT ALOFT FOR FORWARD MOTION/... BUT
WITH LIMITED AVAILABLE MOISTURE THIS FEATURE IS NOT EXPECTED HAVE
AN IMPACT ON ANY RAIN CHANCES. THE STALLED FRONTAL BOUNDARY IS
EXPECTED TO LIFT NORTH DURING THE DAY ON CHRISTMAS EVE WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING BEHIND THIS
BOUNDARY AND PERSISTING OFF-AND-ON THROUGH CHRISTMAS INTO
SATURDAY.

A TROUGH MOVING ALONG THE WEST COAST IS EXPECTED TO CUT OFF
SATURDAY SOMEWHERE OVER NORTHERN MEXICO/WEST TEXAS. THIS CLOSED
LOW IS CURRENTLY FORECAST TO MOVE ACROSS THE STATE SUNDAY THROUGH
TUESDAY... SENDING A STRONG COLD FRONT TOWARDS THE REGION LATE
SUNDAY. TIMING DIFFERENCES STILL EXIST BETWEEN MEDIUM RANGE
GUIDANCE... WITH THE GFS BLASTING THE FRONT THROUGH THE STATE BY
EARLY MONDAY MORNING AND THE EUROPEAN CLEARING THE STATE ALMOST A
FULL DAY LATER.

GIVEN THE TIMING DIFFERENCES... OPTED TO TAKE A BLEND OF MODEL
SOLUTIONS FOR THE WEEKEND FORECAST. WILL NEED TO CONTINUE TO
MONITOR THIS PORTION OF THE FORECAST AS CIPS ANALOG GUIDANCE
INDICATES AT LEAST A LOW SEVERE WEATHER THREAT WITH THIS PATTERN FOR
THE SUNDAY/MONDAY TIMEFRAME AS A LINE OF THUNDERSTORMS DEVELOPS ALONG
THE FRONT. NAEFS ANOMALIES ARE ALSO SHOWING FORECAST PRECIPITABLE
WATER VALUES AROUND TWO STANDARD DEVIATIONS ABOVE CLIMATOLOGICAL
NORMALS... RAISING CONCERNS A HEAVY RAINFALL THREAT /BUT THIS MAY
BE MITIGATED BY THE SPEED OF THE SYSTEM/. WHEN THIS SYSTEM CLEARS
THE REGION THOUGH /BY THE BEGINNING OF NEXT WEEK/... DRIER
WEATHER AND HIGH TEMPERATURES NEAR SEASONAL NORMALS IN THE LOWER
60S ARE EXPECTED.

HUFFMAN

MARINE...
DENSE FOG WILL CONTINUE TO PLAGUE THE COASTAL WATERS AND ADJACENT
BAYS THROUGH THE MORNING. WILL CARRY THE DENSE FOG ADVISORY THROUGH
16Z AND THIS MAY NEED TO BE EXTENDED AS A STUBBORN TEMP INVERSION
LIMITS MIXING. CONDITIONS WILL REMAIN FAVORABLE FOR AREAS OF FOG TO
PERSIST THROUGH THE END OF THE WEEK. MARINERS ARE URGED TO CHECK
THE LATEST FORECAST AND PREPARE FOR RAPIDLY CHANGING CONDITIONS.

A WEAK PRESSURE GRADIENT WILL TIGHTEN THROUGH THE DAY AS LOW
PRESSURE OVER THE WESTERN HIGH PLAINS DEEPENS. MODERATE TO
OCCASIONALLY STRONG ONSHORE WINDS WILL DEVELOP BY EVENING IN
RESPONSE TO THE TIGHTENING GRADIENT. SCEC/SCA CONDS POSSIBLE TONIGHT
INTO WEDNESDAY AS THE STORM SYSTEM OVER THE PLAINS MOVES NORTHEAST.
A LULL IN THE ONSHORE WINDS IS EXPECTED WED NITE/THU BUT WINDS
EXPECTED TO INCREASE AGAIN ON FRI AS ANOTHER AREA OF LOW PRESSURE
DEVELOPS AND INTENSIFIES OVER THE WESTERN PLAINS. A FRONT WILL
CROSS THE COASTAL WATERS NEXT SUN NIGHT AND A WIND SHIFT TO THE
W-NW IS EXPECTED. THE FRONT COULD BRING A LINE OF STRONG STORMS
ACROSS THE MARINE AREAS SUN/MON. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  66  77  55  75 /  20  40  30  10  10
HOUSTON (IAH)              74  65  78  58  77 /  20  30  40  10  20
GALVESTON (GLS)            70  66  73  63  72 /  30  30  40  10  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
     FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...
     CHAMBERS...COLORADO...FORT BEND...GALVESTON...GRIMES...
     HARRIS...HOUSTON...JACKSON...LIBERTY...MADISON...
     MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
     WALKER...WALLER...WASHINGTON...WHARTON.

GM...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
     FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
     FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...
     WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.

     SMALL CRAFT SHOULD EXERCISE CAUTION FROM 3 PM CST THIS AFTERNOON
     THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES: WATERS FROM
     FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
     WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM.

&&

$$

DISCUSSION...14
AVIATION/MARINE...43



AREA FORECAST DISCUSSION...CORRECTED

NWS HOUSTON/GALVESTON TX

 447 AM CST TUE DEC 22 2015

.DISCUSSION...
EARLY MORNING OBSERVATIONS AROUND SOUTHEAST TEXAS SHOW NEAR ZERO
VISIBILITIES FROM DENSE FOG... AND THESE CONDITIONS ARE EXPECTED
TO CONTINUE THROUGH MUCH OF THE MORNING. HAVE EXTENDED THE DENSE
FOG ADVISORY THROUGH 10 AM CST BUT CONCERNED THAT THIS MAY NEED TO
BE EXTENDED WITH THE MORNING UPDATE. HRRR VISIBILITY TRENDS SHOW
FOG LINGERING INTO LATE MORNING... AND THIS SOLUTION MAKES SOME
SENSE WITH FORECAST SOUNDINGS SHOWING A STOUT MORNING INVERSION
ALSO PERSISTING INTO LATE MORNING. THIS WOULD DELAY THE ONSET OF
DAYTIME MIXING AND ALLOW FOG TO HOLD ON A BIT LONGER THAN
ANTICIPATED.

FOR THE REMAINDER OF THE DAY... MESSY SOUTHWEST FLOW WILL CONTINUE
ALOFT WITH LARGE SCALE TROUGHING IN PLACE ACROSS THE WESTERN
CONUS. EARLY MORNING WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
LOCATED OVER THE MEXICAN STATE OF COAHUILA EMBEDDED IN THE FLOW
ALOFT WITH REGIONAL RADAR MOSAIC SHOWING SHOWERS WITH EMBEDDED
THUNDERSTORMS STREAMING ACROSS THE NORTHWESTERN GULF. AS THE
SHORTWAVE OVER MEXICO MOVES TOWARDS THE REGION THIS MORNING...
EXPECT SHOWER AND THUNDERSTORM COVERAGE TO EXPAND NORTHWARD INTO
SOUTHEAST TEXAS. THE ACTUAL TRAJECTORY OF THIS WAVE WILL PLAY A
BIG ROLE IN HOW FAR NORTH RAIN WILL EXTEND INLAND TODAY... AND FOR
NOW ONLY HIGHLIGHTING 20 TO 30 POPS WITH GREATEST COVERAGE
EXPECTED ALONG AND SOUTH OF INTERSTATE 10.

FOR THIS EVENING AND TONIGHT... EXPECT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO DEVELOP ACROSS THE REGION. AS A SHORTWAVE
TROUGH SWINGS ACROSS THE SOUTHERN PLAINS THIS EVENING...
INCREASING FORCING FOR ASCENT WILL OVERSPREAD THE EASTERN HALF OF
THE STATE WITH ISOLATED TO SCATTERED SHOWERS AND POSSIBLY
THUNDERSTORMS BLOSSOMING IN RESPONSE. HIGHLIGHTING GREATEST
CHANCES /40 TO 50 POPS/ OVER THE NORTHERN AND NORTHEASTERN
COUNTIES CLOSER TO THE PASSING TROUGH. SPC IS CURRENTLY
HIGHLIGHTING THESE AREAS WITH A MARGINAL RISK FOR SEVERE
THUNDERSTORMS. FORECAST SOUNDINGS AT COLLEGE STATION AND LUFKIN DO
ADVERTISE MID LEVEL LAPSE RATES AROUND 6-7 KM/C... MLCAPE VALUES
EXCEEDING 1000 J/KG OVERNIGHT... AND 0-6 KM SHEAR VALUES AROUND 40
TO 50 KNOTS. GIVEN THIS... CANNOT RULE OUT AN ISOLATED STRONGER TO
POSSIBLY SEVERE STORM OVER THE NORTHERN AND NORTHEASTERN COUNTIES.
HOWEVER... THESE STORMS WOULD BE THE EXCEPTION AND NOT THE RULE
DUE TO SOME UNCERTAINTY IN ACTUAL THUNDERSTORM COVERAGE.

AS THE SOUTHERN PLAINS SHORTWAVE LIFTS NORTHEAST... IT WILL SEND
A WEAK FRONTAL BOUNDARY INTO THE REGION DURING THE DAY ON
WEDNESDAY. EXPECT LINGERING SHOWERS AND THUNDERSTORMS AHEAD OF THE
BOUNDARY ON WEDNESDAY MORNING. HOWEVER... INCREASINGLY SOUTHWEST
FLOW ABOVE THE SURFACE AS THE TROUGH DEPARTS WILL ADVECT DRIER AIR
OVER THE REGION AND THIS WILL RESULT IN A BRIEF RESPITE IN RAIN
CHANCES WEDNESDAY AFTERNOON THROUGH CHRISTMAS EVE MORNING. HOW
FAR INTO THE REGION THE BOUNDARY WILL MOVE IS STILL A LITTLE
UNCERTAIN... WITH 700 MB FLOW BECOMING INCREASINGLY PARALLEL TO
THE BOUNDARY /LIMITING SUPPORT ALOFT FOR FORWARD MOTION/... BUT
WITH LIMITED AVAILABLE MOISTURE THIS FEATURE IS NOT EXPECTED HAVE
AN IMPACT ON ANY RAIN CHANCES. THE STALLED FRONTAL BOUNDARY IS
EXPECTED TO LIFT NORTH DURING THE DAY ON CHRISTMAS EVE WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING BEHIND THIS
BOUNDARY AND PERSISTING OFF-AND-ON THROUGH CHRISTMAS INTO
SATURDAY.

A TROUGH MOVING ALONG THE WEST COAST IS EXPECTED TO CUT OFF
SATURDAY SOMEWHERE OVER NORTHERN MEXICO/WEST TEXAS. THIS CLOSED
LOW IS CURRENTLY FORECAST TO MOVE ACROSS THE STATE SUNDAY THROUGH
TUESDAY... SENDING A STRONG COLD FRONT TOWARDS THE REGION LATE
SUNDAY. TIMING DIFFERENCES STILL EXIST BETWEEN MEDIUM RANGE
GUIDANCE... WITH THE GFS BLASTING THE FRONT THROUGH THE STATE BY
EARLY MONDAY MORNING AND THE EUROPEAN CLEARING THE STATE ALMOST A
FULL DAY LATER.

GIVEN THE TIMING DIFFERENCES... OPTED TO TAKE A BLEND OF MODEL
SOLUTIONS FOR THE WEEKEND FORECAST. WILL NEED TO CONTINUE TO
MONITOR THIS PORTION OF THE FORECAST AS CIPS ANALOG GUIDANCE
INDICATES AT LEAST A LOW SEVERE WEATHER THREAT WITH THIS PATTERN FOR
THE SUNDAY/MONDAY TIMEFRAME AS A LINE OF THUNDERSTORMS DEVELOPS ALONG
THE FRONT. NAEFS ANOMALIES ARE ALSO SHOWING FORECAST PRECIPITABLE
WATER VALUES AROUND TWO STANDARD DEVIATIONS ABOVE CLIMATOLOGICAL
NORMALS... RAISING CONCERNS A HEAVY RAINFALL THREAT /BUT THIS MAY
BE MITIGATED BY THE SPEED OF THE SYSTEM/. WHEN THIS SYSTEM CLEARS
THE REGION THOUGH /BY THE BEGINNING OF NEXT WEEK/... DRIER
WEATHER AND HIGH TEMPERATURES NEAR SEASONAL NORMALS IN THE LOWER
60S ARE EXPECTED.

HUFFMAN

&&

.MARINE...
DENSE FOG WILL CONTINUE TO PLAGUE THE COASTAL WATERS AND ADJACENT
BAYS THROUGH THE MORNING. WILL CARRY THE DENSE FOG ADVISORY THROUGH
16Z AND THIS MAY NEED TO BE EXTENDED AS A STUBBORN TEMP INVERSION
LIMITS MIXING. CONDITIONS WILL REMAIN FAVORABLE FOR AREAS OF FOG TO
PERSIST THROUGH THE END OF THE WEEK. MARINERS ARE URGED TO CHECK
THE LATEST FORECAST AND PREPARE FOR RAPIDLY CHANGING CONDITIONS.

A WEAK PRESSURE GRADIENT WILL TIGHTEN THROUGH THE DAY AS LOW
PRESSURE OVER THE WESTERN HIGH PLAINS DEEPENS. MODERATE TO
OCCASIONALLY STRONG ONSHORE WINDS WILL DEVELOP BY EVENING IN
RESPONSE TO THE TIGHTENING GRADIENT. SCEC/SCA CONDS POSSIBLE TONIGHT
INTO WEDNESDAY AS THE STORM SYSTEM OVER THE PLAINS MOVES NORTHEAST.
A LULL IN THE ONSHORE WINDS IS EXPECTED WED NITE/THU BUT WINDS
EXPECTED TO INCREASE AGAIN ON FRI AS ANOTHER AREA OF LOW PRESSURE
DEVELOPS AND INTENSIFIES OVER THE WESTERN PLAINS. A FRONT WILL
CROSS THE COASTAL WATERS NEXT SUN NIGHT AND A WIND SHIFT TO THE
W-NW IS EXPECTED. THE FRONT COULD BRING A LINE OF STRONG STORMS
ACROSS THE MARINE AREAS SUN/MON. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  66  77  55  75 /  20  40  30  10  10
HOUSTON (IAH)              74  65  78  58  77 /  20  30  40  10  20
GALVESTON (GLS)            70  66  73  63  72 /  30  30  40  10  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
     FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...
     CHAMBERS...COLORADO...FORT BEND...GALVESTON...GRIMES...
     HARRIS...HOUSTON...JACKSON...LIBERTY...MADISON...
     MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
     WALKER...WALLER...WASHINGTON...WHARTON.

GM...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
     FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
     FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...
     WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.

&&

$$

DISCUSSION...14
AVIATION/MARINE...43





AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 253 PM MST TUE DEC 22 2015

.SYNOPSIS...
PACIFIC MOISTURE WILL SPREAD ACROSS THE REGION THROUGH THE WEEK
RESULTING IN PERIODS OF CLOUDINESS AND CHANCES FOR
PRECIPITATION...MAINLY NORTH AND EAST OF PHOENIX. THE BEST CHANCES
FOR RAIN APPEAR TO BE TONIGHT INTO WEDNESDAY AND AGAIN THURSDAY INTO
CHRISTMAS. WHILE THESE SYSTEMS DO NOT LOOK VERY WET...THEY COULD MAKE
FOR DIFFICULT TRAVEL CONDITIONS ACROSS NORTHERN ARIZONA. TEMPERATURES
WILL REMAIN NEAR NORMAL BUT ARE EXPECTED TO DROP LATE IN THE WEEK AND
INTO THE WEEKEND AS A STRONG AND COLD LOW PRESSURE SYSTEM AFFECTS THE
DESERT SOUTHWEST. SOME GUSTY DAYTIME WINDS AND SUB FREEZING NIGHTTIME
TEMPERATURES WILL BE POSSIBLE OVER THE WEEKEND FOR THE LOWER DESERTS.

&&

.DISCUSSION...
LATEST VISIBLE SATELLITE SHOWS WIDESPREAD THICK STRATOCU AND
NUMEROUS AREAS OF MOUNTAIN WAVE CLOUDINESS ACROSS AZ. LATEST RADAR
CONTINUES TO SHOW BACKBUILDING LIGHT RAIN AND SPRINKLES ACROSS
NORTHERN MARICOPA COUNTY...INCLUDING PORTIONS OF THE PHOENIX AREA.
DESPITE THE PRESENCE OF A 100+ KT 250 MB JET...VORTICITY AND JET-
FORCED ASCENT REMAIN RELATIVELY WEAK. LIGHT PRECIPITATION APPEARS TO
BE MORE A RESULT OF THE SUFFICIENT MOISTURE TRANSPORT FROM THE
REMNANT ATMOSPHERIC RIVER COUPLED WITH ANOMALOUSLY STRONG MID-LEVEL
FLOW AND SUBSEQUENT OROGRAPHIC INFLUENCES. 500 MB WIND SPEEDS ARE NOT
EXACTLY OFF THE CHART...BUT CLOSE TO THE 90TH PERCENTILE PER THE SPC
SOUNDING CLIMATOLOGY AND NAEFS PERCENTILES.

THE THICK CLOUDINESS HAS INHIBITED INSOLATION AND TEMPERATURES HAVE
STRUGGLED TO GET THROUGH THE LOWER-MID 50S...STILL WELL ABOVE THE
RECORD LOW MAXIMUM OF 46 DEGREES IN PHOENIX. HI-RES WRFS ALONG WITH
THE NCAR ENSEMBLE AND LATEST RUNS OF THE HRRR INDICATE THAT THE
LIGHT PRECIP WILL GRADUALLY WORK EASTWARD INTO GILA COUNTY TONIGHT AND
EVENTUALLY SOUTHWARD TOWARDS PINAL COUNTY. ANY RAIN THAT DEVELOPS
WILL LIKELY ONLY AMOUNT TO A FEW HUNDREDTHS OF AN INCH AT MOST IN THE
LOWER DESERTS.

LATEST GFS AND ECMWF REMAIN IN GOOD AGREEMENT THE NEXT FEW
DAYS...INDICATING THAT THE MOIST NORTHWESTERLY FLOW WILL PERSIST.
TREND HAS BEEN A LITTLE BIT FURTHER TO THE EAST ACROSS THE HIGHER
TERRAIN OF MARICOPA AND GILA COUNTIES WITH REGARD TO THE BEST CHANCE
OF PRECIP. CONSEQUENTLY...FORECAST POPS HAVE BEEN REFINED TO DECREASE
VALUES FURTHER WEST AND INCREASE THEM ACROSS GILA COUNTY...IN LINE
WITH THE VALUES FROM THE LATEST GEFS REFORECAST CALIBRATED TO CLIMO.
LATEST MULTI-MODEL ENSEMBLE MEDIAN ALSO SUGGESTS THAT STORM TOTALS
ACROSS THE HIGHER TERRAIN OF GILA COUNTY COULD REACH A HALF OF AN
INCH THROUGH CHRISTMAS EVE. NO SIGNIFICANT CHANGES WERE MADE TO THE
TEMPERATURES...WHICH REMAIN AT OR BELOW NORMAL.

&&

.PREVIOUS DISCUSSION...
THE NEXT BETTER ORGANIZED SYSTEM WILL DEVELOP OUT OF THE GULF OF
ALASKA AND ARRIVE INTO OUR AREA LATE THURSDAY AND INTO FRIDAY. THIS
PARTICULAR SYSTEM WILL QUICKLY MOVE INTO THE AREA AND CUT-OFF FROM
THE MAIN STORM TRACK WHILE BRINGING A SIGNIFICANT COLD POOL AND
FORCING INTO THE REGION. TIGHT INTERSECTION OF FRONTOGENETICAL
FORCING AND MOISTURE BEFORE DRIER AIR BEGINS TO WRAP INTO THE AREA
FROM THE NORTH LIMITS PRECIPITATION AGAIN MAINLY ACROSS
NORTHERN/EASTERN AZ...EVEN LIMITING PRECIP CHANCES FOR THE PHX AREA
COME FRIDAY AND INTO SATURDAY. WITH THE SYSTEM LOOKING TO BE VERY
COLD...500 MB TEMPS AT -31C/700 MB TEMPS AT -14C AND 850 TEMPS AT -
2.5C ALL POSSIBLE UNDER THE STRONGER SCENARIOS...SNOW LEVELS WILL
DROP TO 3000 FEET OR POSSIBLY LOWER. THUS THE BIGGEST IMPACT WILL
LIKELY BE FOR TRAVELERS INTO OR ACROSS THE HIGHER ELEVATIONS AREAS OF
AZ. STRONG FUNNELING WINDS ALONG THE EASTERN FRINGE OF THE
SUBTROPICAL PACIFIC RIDGE AND THE DEPARTING CUT-OFF LOW WILL LEAD TO
WINDY CONDITIONS ALONG THE CO RIVER VALLEY FOR SATURDAY. LINGERING
INTO SUNDAY STRONG GUSTY WINDS FROM THE NORTH MAY CAUSE DIFFICULT
TRAVEL PERIODS FOR MOTORISTS ALONG EAST-WEST ORIENTED
ROADWAYS...INCLUDING INTERSTATE 8/10.

CLEARING SKIES...STRONG SURFACE HIGHS AND REINTRODUCTION OF THE
SIGNIFICANTLY COLDER AIRMASS WILL LEAD VERY COOL WEEKEND DAYTIME
TEMPERATURES AS WELL AS ANOTHER ROUND OF FREEZING OR SUB-FREEZING
TEMPERATURES FOR SOME OUTLYING LOWER ELEVATION DESERTS SATURDAY AND
SUNDAY MORNINGS. FOR THE EARLY NEXT WEEK...SOME DISCREPANCY REMAINS
BETWEEN THE DETERMINISTIC AND ENSEMBLE SUITES WITH THE TIMING OF
SHORTWAVE RIDGING AND ADDITIONAL LOW PRESSURE FEATURES PASSING
THROUGH THE REGION. AT THE MOMENT THOUGH WITH THE RE-ESTABLISHED DRY
AIRMASS AND LOSS OF ENHANCED MOISTURE FLOW FROM OFF THE NORTHEASTERN
PACIFIC THESE LOW PRESSURE WAVES APPEAR TO LACK MUCH BY WAY OF
PRECIP FOR THE FORECAST AREA AHEAD OF THE NEW YEAR`S HOLIDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MOIST NORTHWEST FLOW ALOFT CONTINUES...WITH CIGS SETTLING AOB 5000FT
FOR THE NEXT 24 HOURS OR SO. ISOLD TO SCT -SHRA POSSIBLE THROUGH THE
AFTERNOON/EVENING...WITH CIGS LOWERING TO NEAR 3000FT AFTER 07Z
WEDNESDAY MORNING. VISIBILITY LIKELY TO DETERIORATE AS THE EVENING
PROGRESSES...DROPPING TO NEAR 3SM IN HZ/BR BY 10Z...WITH POTENTIAL
FOR DZ TO TAKE VISIBILITY DOWN TO LESS THAN 1SM FOR PERIODS OF TIME
AT ANY TERMINAL...ESPECIALLY AT KSDL. WINDS EXPECTED TO BE LIGHT AND
FAVOR THE EAST-SOUTHEAST FOR THE NEXT 24 HOURS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
CIGS AROUND 8000FT EXPECTED TO PERSIST THROUGH MID-DAY...WITH CIGS
IMPROVING AND CLOUD DECKS SCATTERING OUT THIS AFTERNOON/EVENING.
EXPECT GUSTY WEST-SOUTHWEST WINDS TO NEAR 30KT AT KIPL/KBLH UNTIL
AROUND 03Z THIS EVENING...WINDS DIMINISHING LATER BUT GENERALLY 15KT
OR LESS OVERNIGHT INTO WEDNESDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A LOW PRESSURE SYSTEM WILL AFFECT THE DISTRICTS INTO THE WEEKEND...
BRINGING WIDELY SCATTERED DESERT RAIN AND MOUNTAIN SNOW SHOWERS FROM
MARICOPA COUNTY EASTWARD...WITH SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA DESERTS REMAINING DRY. AS THE LOW MOVES THROUGH THE
REGION...WINDS WILL INCREASE OUT OF THE NORTH-NORTHWEST WITH GUSTS
UP TO 40 MPH POSSIBLE ACROSS SOUTHEAST CALIFORNIA AND ALONG THE
LOWER COLORADO RIVER VALLEY SATURDAY. MUCH LESS WIND ALONG WITH
DRIER CONDITIONS ARE EXPECTED AREA-WIDE SUNDAY AS THE UPPER LOW
SHIFTS OFF TOWARDS THE EAST. MUCH DRIER AIR WILL SPREAD INTO THE
AREA BEHIND THE DEPARTING LOW...WITH MINIMUM HUMIDITY VALUES
DROPPING BACK INTO THE TEENS OVER MUCH OF SOUTHEAST CALIFORNIA AND
THE SOUTHWEST ARIZONA DESERTS INTO EARLY NEXT WEEK.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...NOLTE
AVIATION...MEYERS
FIRE WEATHER...CB/MEYERS




AREA FORECAST DISCUSSION

NWS MELBOURNE FL

 240 PM EST TUE DEC 22 2015

.DISCUSSION...

...MUCH ABOVE NORMAL TEMPERATURES THE REST OF THE WEEK...
...MODERATE TO HIGH RISK OF RIP CURRENTS THRU THE UPCOMING HOLIDAY
WEEKEND...

TONIGHT-WED...LARGE HIGH PRESSURE RIDGE EXTENDING FROM NEAR
BERMUDA TO CENTRAL FLORIDA WILL RULE IN THE LOWER LEVELS. THIS
WILL CONTINUE THE WARM AND MOIST SOUTHEAST/SOUTH WIND FLOW WITH
ELEVATED PRECIPITABLE WATER VALUES.

CONVECTION SO FAR THIS AFTERNOON HAS BEEN IN THE FORM OF SMALL
ISOLATED SHOWERS. RECENT HRRR MODEL RUNS HAVE BACKED OFF
DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED STORMS THAT IT HAD
BEEN SHOWING EARLIER. STILL THERE ARE SOME CLOUD BOUNDARIES NOTED
ON SATELLITE...SO WE WILL KEEP A SMALL CHANCE FOR SHOWERS IN THE
FORECAST THROUGH EVENING.

THE MAV GUIDANCE AGAIN SHOWS CONSIDERABLE LATE NIGHT STRATUS
DEVELOPING...BUT NOT QUITE AS MUCH FOG AS IT DID LAST NIGHT (WHEN
THERE WAS JUST A PATCH OR TWO OF GROUND FOG). THERE WILL AGAIN BE
CONSIDERABLE CLOUDINESS THROUGH THE NIGHT WITH BOUNDARY LAYER
WINDS AROUND 15 KNOTS...SO WILL NOT FORECAST ANY SIGNIFICANT FOG.

ON WED...MOS POPS ARE VERY LOW BUT IT WILL STAY VERY WARM AND
MOIST. THERE WILL BE CONSIDERABLE HIGH CLOUDINESS AGAIN BUT A FEW
RECORD HIGHS ARE STILL POSSIBLE. FORECAST SOUNDINGS DO NOT SHOW
ANY SIGNIFICANT CAPPING SO WILL KEEP A SMALL CHANCE FOR SHOWERS.

WED NIGHT/THU/THU NIGHT...A SHORTWAVE TROUGH WILL LIFT INTO THE
UPPER MS VALLEY WITH DEEPER MOISTURE ACROSS N FL AND THE SOUTHEAST
WED NIGHT. THE ATLC RIDGE WILL BUILD AT H5 FROM THE EAST TWD FL WITH
LOW LVL SSE KEEPING OVERNIGHT LOWS WARM IN THE UPPER 60S TO LOWER
70S. SSE LOW LVL WINDS EXPECTED ON THU WITH WARM TEMPS AGAIN NEAR
RECORD LEVELS ON CHRISTMAS EVE INTO THE LOWER 80S ALONG THE BEACHES
AND MID 80S INLAND. PWATS FROM 1.3 TO 1.5 INCHES ARE FORECAST WITH
DRYING FORECAST THROUGH THE DAY IN THE H8-H3 LAYER SO WILL CONTINUE
THE DRY AND VERY WARM FORECAST. LOW LVL FLOW WILL VEER SOME TO THE
SE THU NIGHT AND MAY ALLOW A LATE NIGHT SHOWER TO APPROACH THE COAST
FROM THE CAPE TO MARTIN COUNTY. OTHERWISE ANOTHER WARM NIGHT IS
EXPECTED WITH LOWS IN THE UPPER 60S FOR THE INTERIOR AND LOWER 70S
ALONG THE EAST COAST.

MODIFIED EXTENDED DISCUSSION...FRI-TUE...WHILE OVERALL DEEP LAYER
RIDGING MAY WEAKEN AND SHIFT SLOWLY WESTWARD THROUGH THIS TIME IT
STILL REMAINS A PERMANENT FIXTURE FOR OUR WEATHER WITH CONTINUED
SERLY FLOW OCNLY BREEZY ALONG THE COAST DURING THE DAY. THE SURFACE
RIDGING WILL LIFT SLOWLY NORTHWARD THRU THE WEEKEND. PRECIPITATION
CHANCES GENERALLY 20 PERCENT OR LESS AREAWIDE THROUGH THE EXTENDED
PERIOD. A WARMER THAN NORMAL PATTERN CONTINUES INTO MONDAY AND
TUESDAY NEXT WEEK WITH ADDITIONAL RECORD HIGHS AND WARM MINIMUM
TEMPERATURES LIKELY AS HIGHS REACH THE LOWER TO MID 80S AND LOWS
FORECAST IN THE UPPER 60S TO LOWER 70S.

&&

.AVIATION...
MAINLY VFR CONDITIONS THROUGH EVENING THOUGH LOCAL MVFR IS
POSSIBLE WITH ISOLATED SHOWERS. MAV GUIDANCE HAS SOME IFR
TO LIFR STRATUS FOR THE INTERIOR TERMINALS LATE TONIGHT WITH EVEN
DENSE FOG AT KLEE. THE GUIDANCE DID THAT FOR LAST NIGHTS FORECAST
TOO AND THERE WAS VERY LITTLE STRATUS/FOG. BOUNDARY LAYER WINDS
ARE FORECAST TO BE ABOUT THE SAME OVERNIGHT...NEAR 15 KNOTS AND
ALSO EXPECT CONSIDERABLE CLOUDINESS TO LINGER. HENCE...DID NOT HIT
THE STRATUS OR FOG HARD WITH THE PREVIOUS SET OF TAFS. WED WILL BE
ANOTHER QUITE WARM AND HUMID DAY WITH LOCAL MVFR CEILINGS AND
SMALL SHOWER CHANCES.

&&

.MARINE...
TONIGHT-WED...THE LATEST GFS SHOWS SLIGHT BAGGINESS IN THE
PRESSURE GRADIENT DISSIPATING THIS EVENING AND THEN SLIGHT
TIGHTENING INTO WED AFTERNOON. SOUTHEAST/SOUTH FLOW 15-20 IS
INDICATED IN THE GULF STREAM...SO WILL CONTINUE WITH EXERCISE
CAUTION STATEMENTS THERE. CLOSE TO THE COAST...WINDS LOOK TO BE
10-15 KNOTS...STILL NOT GREAT CONDITIONS FOR SMALL CRAFT
OPERATORS.

THU-SUN...PRESSURE GRADIENT AROUND THE ATLANTIC RIDGE OFFSHORE WILL
SUPPORT SE WINDS TO 15 KNOTS...15-20 KNOTS AT TIMES THROUGH THE
UPCOMING HOLIDAY WEEKEND. THIS WILL KEEP SEAS ELEVATED...GENERALLY
AROUND 6 FT OFFSHORE AND 4-5 FT NEAR SHORE FROM CHRISTMAS EVE
THROUGH SUNDAY.

&&

.CLIMATE...DAYTONA BEACH HAD A MORNING LOW OF 71 DEGREES THIS
MORNING AND TEMPERATURES ARE NOT FORECAST TO GO BELOW THAT THIS
EVENING...SO THEY WILL LIKELY HAVE A RECORD WARM LOW FOR TODAY.
HIGHER CHANCES FOR WARM TEMPERATURE RECORDS WED-CHRISTMAS DAY.

RECORD HIGHS TUE THROUGH FRI...

      DEC-22     DEC-23     DEC-24     DEC-25
DAB  85(2013)   85(2013)   84(1981)   82(1988)
MCO  86(2013)   86(2013)   85(2014)   85(1924)
MLB  84(2013)   86(2013)   85(2014)   87(1981)
VRB  84(2013)   84(2013)   87(2014)   85(1997)

RECORD WARM LOWS TUE THROUGH FRI...

      DEC-22     DEC-23     DEC-24     DEC-25
DAB  70(2006)   68(2013)   67(1997)   69(1997)
MCO  68(1911)   68(1911)   67(2006)   69(1997)
MLB  73(2006)   68(2006)   71(1987)   72(1997)
VRB  74(2006)   69(2013)   72(2014)   71(1997)

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  71  84  69  83 /  30  20  10  10
MCO  70  85  70  86 /  30  20  10  10
MLB  73  85  71  84 /  30  20  10  10
VRB  73  85  70  85 /  30  20  10  10
LEE  71  85  70  85 /  30  20  10  10
SFB  70  86  70  85 /  30  20  10  10
ORL  71  85  71  85 /  30  20  10  10
FPR  73  84  71  85 /  30  20  10  10

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&

$$

SHORT TERM/AVIATION...LASCODY
LONG TERM....VOLKMER




AREA FORECAST DISCUSSION

National Weather Service Lincoln IL

 1149 AM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 922 AM CST TUE DEC 22 2015

Large shield of stratus remains in place over the area this
morning, with cirrus starting to move in on top of it west of the
Illinois River. While most of the computer models show some
scouring out of the low clouds, our morning sounding showed a
rather a rather tight inversion around 2000 feet that likely will
not be going anywhere fast. HRRR guidance shows a couple thin
spots trying to form, but largely keeps the low clouds over the
entire area into the evening. The existing sky grids already had a
good handle on that. Because of the extensive clouds, have lowered
highs a couple degrees across the northern CWA, but temperatures
still will get a nice bump upward as the southerly flow gets
stronger this afternoon.

Minor grid updates have been sent, but no changes to the worded
forecast are needed at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 330 AM CST TUE DEC 22 2015

Cold front that triggered scattered showers and thunderstorms across
east-central and southeast Illinois earlier this evening has now
pushed into Indiana, leaving behind cloudy but dry conditions across
the KILX CWA early this morning.  Despite surface high pressure
building into the region, do not think any clearing will occur
today.  Models show a strong subsidence inversion developing at
around 925mb, essentially trapping the lingering boundary layer
moisture in the form of a low overcast.  With such a strong
inversion in place and no appreciable advection to get rid of the
clouds, see little hope for any sunshine today. Due to the
extensive cloud cover, have undercut the MAV guidance numbers,
resulting in high temperatures in the middle to upper 40s.

.LONG TERM...(Tonight through Monday)
ISSUED AT 330 AM CST TUE DEC 22 2015

Warm and unsettled weather will be the rule over the next several
days...with the potential for severe thunderstorms and record high
temperatures on Wednesday and copious amounts of rainfall next
weekend.

As high pressure moves off to the east, increasing southwesterly
flow will bring warmer/more humid air into the region tonight into
Wednesday.  NAM forecast soundings are showing the boundary layer
becoming saturated as increasing moisture flows northward,
suggesting the potential for fog/drizzle tonight.  With low pressure
ejecting out of the Rockies, scattered showers will arrive late
tonight, although the bulk of the precipitation will hold off until
Wednesday.

A potentially volatile day is unfolding on Wednesday as deepening
low pressure tracks from near Kansas City early in the day to Lake
Superior by evening.  Strong southerly winds gusting to between 30
and 40 mph ahead of the approaching system will bring an
unseasonably warm and humid airmass into Illinois, with afternoon
high temperatures climbing to near record levels in the middle 60s
and surface dewpoints reaching the middle to upper 50s.  Models
continue to show strong instability developing for this time of
year, with NAM SBCAPES of 500-1000J/kg and lifted index values of -2
to -4C. At the same time, 0-6km bulk shear will increase to between
70 and 80kt along/south of the I-70 corridor.  Latest Day 2
convective outlook from SPC now places all areas east of the
Illinois River under a Slight Risk for severe.  Based on current
projections and model forecast parameters, it appears the primary
severe weather threats will be damaging wind gusts and large hail,
although an isolated tornado will also be possible given the
increasing shear values.  The main time frame for severe will be
during the afternoon east of the Illinois River, shifting to
along/east of the I-57 corridor by early evening.  Cold front will
sweep through the region by around midnight, with rain chances
ending overnight.

Once the Wednesday system departs, quiet weather will be on tap for
both Thursday and Friday with dry conditions and mild high
temperatures in the 40s and 50s.  After that, a return to warm/wet
weather is in store by next weekend as deep-layer southwesterly flow
re-establishes itself across the central/eastern CONUS in advance of
the next major storm system.  All models show an upper trough
digging southward across the western CONUS late in the week,
eventually forming a closed low over the Desert Southwest by
Saturday.  How quickly this feature ejects northeastward is still in
question, with the 00z Dec 22 GFS showing a much faster solution
than the ECMWF.  With such a deep closed low expected to form and
essentially cut itself off from the main flow well to the north,
think slower is the way to go.  As a result, have trended toward the
ECMWF from Saturday through Monday.  The ECMWF shows rain spreading
northward well ahead of the upper low along a prevailing baroclinic
zone Saturday/Saturday night.  After that, rain will continue
through early next week...although there is some indication that a
northern stream short-wave may temporarily push the frontal boundary
a bit further southward and possibly bring a break in the precip
late Sunday into Monday before the upper low tracks into the region
by Monday night into Tuesday.  At this point, will just keep PoPs
going right through the period and will make adjustments as
necessary as better model agreement is achieved.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1150 AM CST TUE DEC 22 2015

IFR conditions remain widespread at midday. Some breaks in the
clouds developing near KSPI with the edge of the stratus deck
along the Missouri River north of KSTL. Will need to watch to see
if this can make more progress into central Illinois, but
currently think that there would only be an improvement to MVFR
at best, as wind trajectory becomes more southerly and pushes the
clearing line further north. Some of the high-resolution guidance
has been suggesting some dense fog development in east central
Illinois late this afternoon into evening. Winds increase quite a
bit and would not necessarily favor dense fog, but have lowered
visibilities somewhat before a more widespread 1SM this evening as
was indicated in the previous TAF set. Showers will quickly work
their way across central Illinois Wednesday morning as a strong
storm system lifts northeast across Iowa. Thunder potential is a
bit borderline at the moment and have left it out, but will need
to be monitored. The storm is rather intense, so winds will ramp
up and gust near 30 knots by midday in most of the area.

&&

.CLIMATE...
ISSUED AT 932 AM CST TUE DEC 22 2015

Record highs for Wednesday:

Bloomington/Normal......... 63 in 1933
Champaign/Urbana........... 64 in 1933
Charleston/Mattoon......... 69 in 1933
Danville................... 65 in 1933
Decatur.................... 66 in 1933
Effingham.................. 68 in 1933
Jacksonville............... 70 in 1933
Lincoln.................... 65 in 1933
Olney...................... 67 in 1931
Peoria..................... 65 in 1933
Springfield................ 66 in 1933

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

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




AREA FORECAST DISCUSSION

NWS DES MOINES IA

 409 PM CST TUE DEC 22 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 345 PM CST TUE DEC 22 2015

REMNANTS OF THE MORNING STRATUS SHIELD REMAIN OVER THE NORTHEASTERN
THIRD TO HALF OF THE STATE AND WILL GENERALLY REMAIN SO THIS EVENING
AS THE STRONG INVERSION REMAINS IN PLACE AND WE LOSE WHATS LEFT OF
ANY DAYTIME HEATING AND MIXING. AS A RESULT...CEILINGS AND
VISIBILITIES WILL CONTINUE TO BE LOW IN THOSE AREAS...AROUND 500
FEET AND A COUPLE MILES OR LESS RESPECTIVELY THROUGH THE SHORT TERM.
HAVE NOT CURRENTLY INTRODUCED FOG INTO THE GRIDS...BUT MAY WARRANT
SO DURING THE EVENING...ESPECIALLY FOR AREAS THAT HOLD OFF ON SEEING
PRECIP LONGER AND MOISTURE ADVECTION CONTINUES. AREAS THAT SAW
CLEARING WILL PROGRESSIVELY SEE HIGH BASED CLOUDS MOVE IN BEFORE
CEILINGS FALL AGAIN AS SURFACE LOW AND FORCING PROGRESSES TOWARDS
THE REGION FROM CENTRAL/EASTERN KANSAS.

THE AFOREMENTIONED SURFACE LOW WILL BE THE MAIN CONCERN IN THE SHORT
TERM...BEGINNING TO REALLY INFLUENCE THE AREA AFTER 03Z. THROUGH THE
DAY...NAM AND HRRR HAVE TENDED TO HANDLE THE CLEARING BEST...SO HAVE
TRENDED THAT WAY IN THE GRIDS FOR THIS EVENING. WITHIN THE SHORT
TERM WINDOW...BEST INITIAL FORCING IS THERMODYNAMIC WITH A GOOD PUSH
OF THETA-E ADVECTION ALONG WITH ISENTROPIC LIFT IN THE 290K REGION.
THE DEFORMATION ZONE WILL ALSO BEGIN TO SET UP IN NORTHWEST IOWA
AFTER 06Z...FURTHER BOOSTING LIFT. CURRENTLY...THE COLUMN IS QUITE
DRY FROM ABOUT 850MB TO 500MB...WHICH CALLS INTO SOME QUESTION WHEN
THE COLUMN WILL SATURATE AND PRECIP WILL BEGIN...BUT BEGAN TO UP
POPS IN NORTHWEST IOWA AROUND 5Z AND THROUGH THE SHORT TERM WINDOW
IN CONJUNCTION WITH HRRR/NAM SOLUTIONS.

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 345 PM CST TUE DEC 22 2015

THE LONG TERM REMAINS ACTIVE WITH SEVERAL SHORTWAVES EJECTING OUT
OF THE BAST OF A LONG WAVE TROUGH OUT WEST. WE BEGIN THE PERIOD
WITH THE SYSTEM AFFECTING THE SHORT TERM LIFTING NORTHEAST. THERE
WILL BE A BRIEF PERIOD OF OF SNOW ON THE BACKSIDE OF THIS SYSTEM
AS IT LIFTS OFF TO THE NORTHEAST. MOST OF THE FORCING EXITS BEFORE
THE CHANGEOVER SO I AM NOT LOOKING AT MUCH ACCUMULATION PLUS WE
WILL BE TOO WARM ALOFT...MAY EVEN SEE A BIT OF FREEZING RAIN WITH
THIS. ALSO...SOME INSTABILITY WORKS INTO EASTERN IOWA AS THIS
SYSTEM LIFTS OUT WHICH MEANS WE COULD SEE SOME ISOLATED THUNDER
WEDNESDAY AFTERNOON. AFTER THIS SYSTEM DEPARTS THERE WILL BE A
BRIEF RESPITE WEDNESDAY NIGHT BEFORE ANOTHER WEAK SHORTWAVE
TRANSLATES ACROSS THE SOUTH AND EAST. TEMPS WILL BE WARM ENOUGH
FOR RAIN WITH THIS SO NOT FORESEEING MUCH IN THE WAY OF TRAVEL
PROBLEMS BUT WITH RIVERS STILL VERY HIGH...ANY HEAVIER RAINFALL
WILL LIKELY RESULT IN FLOODING AGAIN.

THE NEXT MAIN SYSTEM WILL BE A DEEPENING LOW ACROSS THE SOUTHERN
PLAINS LIFTING NORTHEAST. I THINK THE MODELS ARE LIKELY TOO FAST
WITH THIS SYSTEM GIVEN HOW THE LOW IS DEEPENING BUT INITIALLY THIS
WILL BE A RAIN PRODUCER WITH COLD AIR WRAPPING INTO THE LOW
CHANGING PRECIP OVER TO SNOW. THIS ONE MAY BE A POTENTIAL SNOW
PRODUCER FOR US AND NEEDS TO BE WATCHED BUT WILL ALSO BRING
ADDITIONAL FLOODING THREATS.

&&

.AVIATION...22/18Z
ISSUED AT 1144 AM CST TUE DEC 22 2015

IFR/LIFR CIGS CONTINUE TO DOMINATE EASTERN TWO THIRDS OF
STATE...WHILE CLEARING IS RAPIDLY MOVING INTO EASTERN AND CENTRAL
IOWA. MODELS HAVE NOT HANDLED CLEARING SKIES WELL...BUT TRENDS
SUGGEST IT WILL CONTINUE WELL INTO CENTRAL AND EVEN EASTERN IOWA
BEFORE CLOUDING BACK OVER LATER TODAY/THIS EVENING. WINDS WILL BE
GUSTY AT TIMES TODAY WITH SOUTHEASTERLY WINDS AROUND 15 TO 20 MPH
GUSTING TOWARDS 30 MPH AT TIMES. RETURN OF MVFR/IFR CONDITIONS
OVERNIGHT AS LOW PRESSURE MOVES IN...DROPPING CIGS AND VSBYS...AND
EVENTUALLY RAIN AFTER 06-09Z.


&&

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

$$

SHORT TERM...CURTIS
LONG TERM...FAB
AVIATION...CURTIS




AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 1218 PM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 1215 PM CST TUE DEC 22 2015

LOW STRATUS/MOISTURE TRAPPED UNDER A STRONG INVERSION THIS MORNING
WAS KEEPING TEMPERATURES IN CHECK...ONLY IN THE LOWER TO MID 30S
AT MANY LOCATIONS. VISIBLE SATELLITE SHOWS THIS STRATUS BEING
SCOURED OUT ACROSS WESTERN IA AND CENTRAL MO DUE TO STRENGTHENING
LOW/MID LEVEL WARM AIR ADVECTION. THIS SCOURING OUT OF THE STRATUS
SHOULD MAKE IT INTO THE DVN CWA LATE THIS AFTERNOON. HOWEVER...
THICKENING CIRRUS WILL ALSO BE OVER THE CWA SO THE BOTTOM LINE IS CLOUDY
OR MOSTLY CLOUDY SKIES WILL REMAIN. WITH CONTINUED SOUTHEAST WINDS
THIS AFTERNOON MAXIMUM TEMPERATURES WILL ACTUALLY OCCUR LATE IN
THE DAY OR EARLY THIS EVENING.

STORM SYSTEM STILL EXPECTED TO IMPACT THE MIDWEST LATER TONIGHT
AND ESPECIALLY ON WEDNESDAY. INTENSE CYCLONE WILL TRACK FROM THE
OK PANHANDLE (TONIGHT) TO CENTRAL IA NOON WEDNESDAY (984 MB) AND
THEN TO NORTHERN WI BY WEDNESDAY EVENING (981 MB). THIS WILL PULL
DEEP MOISTURE NORTHWARD ON A 60 KNOT LOW LEVEL JET WITH PWAT`S
INCREASING TO OVER 1 INCH. AHEAD OF THE COLD FRONT VERY STRONG
DEEP LAYER SHEAR WILL EXIST BUT CAPE WILL BE MINIMAL. THE SEVERE
THREAT (INCLUDING TORNADOES) LOOKS TO BE SOUTH AND EAST OF THE
DVN CWA WHERE THE AXIS OF THE STRONGEST LOW LEVEL JET AND HIGHER
CAPE WILL BE LOCATED. HOWEVER...IF OUR EAST/SOUTHEAST CWA CAN GET
ENOUGH SUNSHINE AND A BIT MORE INSTABILITY THEN AT LEAST ISOLATED
DAMAGING WIND OR HAIL IS POSSIBLE...AND A BRIEF TORNADO CAN`T BE
RULED OUT. SPC HAS PULLED THE MARGINAL RISK A BIT FARTHER WEST
INTO EXTREME EASTERN IA. OTHERWISE...MODERATE TO LOCALLY HEAVY
RAINFALL IS LIKELY WHICH WOULD AGGRAVATE THE ALREADY ONGOING RIVER
FLOODING SITUATION.

RECORD HIGH TEMPERATURE IS ALSO POSSIBLE AT MOLINE ON WEDNESDAY
WITH THE RECORD FOR DECEMBER 23 OF 59 SET IN 1982...WHICH ALSO
HAPPENED TO BE A STRONG EL NINO YEAR (1982-83).

&&

.SYNOPSIS...
ISSUED AT 337 AM CST TUE DEC 22 2015

WEAK SURFACE RIDGE IS BUILDING INTO THE AREA EARLY THIS AM.
SATELLITE AND OBS SHOW STRATUS BLANKETING THE ENTIRE AREA AND
MUCH OF THE MIDWEST... WITH THE BACK EDGE NEAR THE MISSOURI
RIVER VALLEY SHOWING LITTLE MOVEMENT HOLDING FIRM BENEATH STRONG
850 MB INVERSION. WEAK ISENTROPIC ASCENT AND WEAK CONVERGENCE
WITH SURFACE TROUGH PRODUCED PATCHY TO AREAS OF FOG AND DRIZZLE
LAST EVENING INTO THE OVERNIGHT... BUT SEEING A DIMINISHING TREND
EARLY THIS AM AS THIS LIFT MIGRATES EAST. WATER VAPOR SHOWS
UPPER LEVEL SHORTWAVE MOVING ACROSS THE UPPER MIDWEST WITHIN
SEMI-ZONAL FLOW PATTERN. MUCH STRONGER WAVE WAS NOTED OVER THE
NORTHERN ROCKIES IN LEFT EXIT REGION OF VIGOROUS UPPER LEVEL JET
NOSING FROM EASTERN PACIFIC INTO THE WESTERN CONUS. THIS SYSTEM
LOOKS TO SHIFT ACROSS THE UPPER MIDWEST ON WEDNESDAY BRINGING
OUR NEXT ROUND OF WET WEATHER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN CHALLENGES ARE CLOUD TRENDS AND IMPACT ON HIGHS... THEN RAIN
CHANCES LATER TONIGHT.

DONT FORESEE MUCH EROSION OF THE STRATUS THIS AM WITH SFC RIDGE
SLIDING ACROSS REGION WITH LIMITED MIXING AND STRONG 850 MB
INVERSION IN PLACE. HOWEVER... REMAINS TO BE SEEN WITH PASSAGE
OF THE MID LEVEL WAVE THIS AM IF INCREASING SUBSIDENCE IN WAKE
CAN HELP BRING ABOUT SOME EROSION AND NOTICING LAST FEW RUNS OF
HRRR DEPICT SOME DECREASE IN LOWER CLOUDS NORTH LATE AM INTO THE
PM. SATELLITE TRENDS ALSO SHOW LITTLE MOVEMENT TO BACK EDGE OF THE
STRATUS NEAR THE MISSOURI RIVER VALLEY EARLY THIS AM... AND SOME
OF THE HI-RES GUIDANCE IS PRETTY AGGRESSIVE IN ERODING THIS FROM
THE SOUTH THIS AFTERNOON INTO EASTERN IA AND WESTERN IL... BUT
NOTICING HRRR TRENDING SLOWER WITH THIS PROCESS AND WOULD SUGGEST
SOME EROSION UP TO OUR SOUTHERN CWA BUT MAINLY FURTHER SOUTH.
DO FEEL SOME EROSION OF STRATUS IS LIKELY ESPECIALLY ON THE WEST
AND SOUTH SIDE OF DECK WITHIN DEVELOPING STRONGER SOUTHERLY FLOW
AND MIXING... BUT ALSO EXPECT INCREASING HIGH CLOUDS AND WITH
THE FLOW GENERALLY SSE NOT FEELING GOOD ON PROSPECTS FOR MUCH IN
WAY OF SUNSHINE TODAY AND THUS STAYED WITH CLOUDY-MOCLDY SKY
FORECAST TODAY. AS A RESULT OF STAYING PESSIMISTIC WITH CLOUDS
LOWERED HIGHS A TOUCH AND SIDED ON COOL SIDE OF GUIDANCE BLEND
WITH RANGE AROUND 40 TO MID 40S. HOWEVER... IF NO LIFTING OR
THINNING OF STRATUS OCCURS THEN WILL BE COLDER AND MORE IN RANGE
OF MID 30S NORTH TO LOWER 40S SOUTH. ON THE OTHER SIDE OF THIS
IF WE WERE TO SEE MORE EROSION OF STRATUS THIS AFTERNOON WITH
ONSET OF GUSTY SSE WINDS AND BETTER MIXING THEN COULD EASILY SEE
HIGHS WELL INTO THE 40S TO LOWER 50S. BOTTOM LINE... AS CLOUD
TRENDS GO... SO GO TEMPS. TYPICALLY BETTER TO STAY CONSERVATIVE/
PESSIMISTIC WITH CLOUD AND TEMP TRENDS THIS TIME OF YEAR... AS
DECEMBER IS OUR CLOUDIEST MONTH.

AS FOR WINDS TODAY... SHOULD BECOME GUSTY BY AFTERNOON FROM S/SE
15-25 MPH... WITH TIGHTENING PRESSURE GRADIENT BETWEEN NORTHERN
PLAINS TO LEE SIDE CYCLONES AND GREAT LAKES HIGH PRESSURE RIDGE.
WINDS LIKELY TO REMAIN OCCASIONALLY GUSTY TONIGHT WITH CONTINUED
RAMPING UP OF LOW LEVEL JET AND LINGERING SFC PRESSURE GRADIENT.

ISENTROPIC ASCENT/WARM ADVECTION WITH STRENGTHENING LOW LEVEL JET
SHOULD FOSTER INCREASING SHOWER ACTIVITY OVERNIGHT... ESPECIALLY
WEST AND SOUTHWEST OF QUAD CITIES. CANT RULE OUT A RUMBLE OF
THUNDER ESPECIALLY FAR SOUTHWEST CWA WITHIN PLUME OF STEEP LAPSE
RATES 7-8C/KM IN 600-750 LAYER... BUT FEELING FAIRLY ISOLATED AND
HAVE LEFT OUT MENTION ATTIM.

TEMPS SHOULD DROP VERY LITTLE EARLY THIS EVENING AND PRETTY MUCH
BE STEADY TO GRADUALLY RISING TONIGHT WITH CONTINUED WARM
ADVECTION. DEPENDING ON WHAT TEMPS DO TODAY... ITS VERY POSSIBLE
TO SEE HIGHS FOR THE DAY SOME AREAS OCCUR THIS EVENING...
ESPECIALLY NORTHERN CWA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 337 AM CST TUE DEC 22 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR
PRECIPITATION AND THE CHANGING GUIDANCE.  GUIDANCE HAS NOT SETTLED
ON ANY SOLUTIONS PAST TOMORROW.  THIS LEADS TO AN OVERALL POOR
CONFIDENCE IN THE FORECAST.  MAIN ISSUE WITH THIS IS THAT SOME OF
THE MODEL SOLUTIONS SUGGEST THE POTENTIAL FOR A SIGNIFICANT RAINFALL
EVENT BOTH WEDNESDAY AND AGAIN TOWARDS THE END OF THE WEEKEND. THESE
EVENTS...IF THEY OCCUR WOULD ONLY EXASPERATE AN ALREADY ATYPICAL
DECEMBER HYDRO EVENT.

WEDNESDAY...WEDNESDAY NIGHT...

MODELS ARE IN GOOD AGREEMENT WITH THE TRACK OF THE LOW ACROSS THE
AREA. MUCH LIKE YESTERDAY...TEMPERATURES WILL BE THE 40S TO 50S
ACROSS THE CWA AND MOISTURE STREAMS INTO THE AREA.  WITH PWATS WELL
ABOVE NORMAL AND APPROACHING 1 INCH ACROSS THE AREA...THE POTENTIAL
FOR MODERATE RAINFALL EXISTS.  IT APPEARS THAT WE ONCE AGAIN HAVE A
THREAT FOR THUNDERSTORMS WITH THIS SYSTEM AS THE CLEAR SLOT MAKES
ITS WAY INTO THE AREA.  LAPSE RATES SHOULD STEEPEN IN THE MIXED
PHASE REGION OF AN UPDRAFT...THIS INCREASES THE CHANCES FOR
THUNDER...ESPECIALLY SOUTH AND THEN EAST OF THE QC.  SPC HAS THIS
AREA IN A MARGINAL RISK FOR SEVERE WEATHER ON WEDNESDAY WITH THE
SLIGHT RISK NOT FAR TO OUR EAST.  MY GUT IS TELLING ME THAT THE BEST
CHANCE FOR SEVERE WILL BE WELL TO OUR EAST ASSOCIATED WITH THE H85
JET.  THAT BEING SAID...IF WE WERE TO GET SEVERE WEATHER IT WOULD BE
ASSOCIATED WITH THE CLEAR SLOT IN THE AFTERNOON.  HIRES MODELS
PREDICT A BROKEN LINE OF CONVECTION ALONG THIS INTERFACE.  I THINK
THAT HAIL WOULD BE THE MAIN THREAT IF SEVERE WEATHER OCCURRED.  I
ALSO THINK A BRIEF WEAK SPIN UP IS NOT OUT OF THE QUESTION.
AGAIN...I HAVE VERY LOW CONFIDENCE IN THIS OCCURRING.  WILL MENTION
THE MARGINAL RISK FOR SEVERE WEATHER IN THE HWO WITH THE HAIL THREAT
FOR WEDNESDAY.  ONCE THE SYSTEM MOVES OUT...THE GEM TRIES TO SNEAK
IN ANOTHER WAVE ALONG THE BOUNDARY OVERNIGHT.  I DO NOT THINK THIS
WILL HAPPEN AS IT IS THE OUTLIER OF THE REST OF THE MODELS.  AS SUCH
I DOWNPLAYED IT.  IF IT IS RIGHT...WE COULD SEE SOME SNOW
ACCUMULATION ACROSS NW ZONES.

THURSDAY THROUGH SATURDAY...

MODELS IN GOOD AGREEMENT FOR A QUIET CHRISTMAS EVE AND CHRISTMAS DAY
ACROSS THE AREA WITH HIGH PRESSURE ENTRENCHED ACROSS THE AREA.  THE
POTENTIAL EXISTS FOR SOME CLEARING AS WELL ON CHRISTMAS DAY.  AFTER
CHRISTMAS DAY...INTO SATURDAY...THE GFS AND ECMWF STALL A BOUNDARY
TO OUR SOUTH.  OVERRRUNING MOISTURE MAY GRAZE THE AREA WITH RAIN AND
EVEN SOME RAIN/SNOW MIX ACROSS THE FAR NORTH FRIDAY NIGHT INTO
SATURDAY.  FOR THE MOST PART THE HEAVIEST PRECIP STAYS TO THE SOUTH.
PAST THIS...THE MODELS DIVERGE.

PAST SATURDAY...

WITH GUIDANCE JUMPING RUN TO RUN PAST SATURDAY IM GOING TO DISCUSS
EACH MODELS GUIDANCE AND SUGGESTED OUTCOMES AND THEN DISCUSS WHY I
WENT A COMPROMISE BETWEEN THE GFS AND ECMWF.  NEEDLESS TO SAY...THE
EXTENDED FORECAST IS FULL OF BUSY WEATHER...AND IF THE GFS IS
CORRECT...WE COULD SEE AN ADDITIONAL 2 TO 4 INCHES AND POSSIBLY UP
TO 5 INCHES THROUGH THE NEXT TEN DAYS.

GFS...

THE RECENT GFS RUNS HAVE PUSHED AN EXTREMELY POTENT...NEGATIVELY
TILTED SYSTEM INTO THE AREA.  THIS PULLS A DEEP LOW ACROSS CENTRAL
IOWA.  WITH THE STALLED BOUNDARY TO OUR SOUTH...DEEP MOISTURE WOULD
QUICKLY SURGE INTO THE AREA.   60 DEGREE TEMPS ARE FORECAST FOR THE
FAR SE WITH THIS SYSTEM.  THE WARM SECTOR...WITH BACKED
WINDS...WOULD ROLL OVER THE AREA...LIKELY LEADING TO THUNDERSTORMS
AND INCREASED RAINFALL ACROSS THE AREA.  THE GFS HAS 1 TO 3+ INCHES
OF RAIN IN THIS EVENT.  IF THIS WERE TO OCCUR...WE WOULD LIKELY NOT
HAVE MUCH TIME FOR WATER FROM YESTERDAYS EVENT AND WEDNESDAY EVENT
TO ROUTE THROUGH THE RIVERS...MEANING HIGHER RIVERS AND POSSIBLY
INCREASED FLOODING.   THE NORTHERN EDGE OF THE CWA WOULD EXPERIENCE
A WINTRY MIX INTO SUNDAY NIGHT AND MONDAY MORNING.  AT THIS TIME
HAVE A RA/SN/PL MIX.  THIS SOLUTION WOULD BE THE WORST FROM A HYDRO
POINT OF VIEW.  I HAVE LOW CONFIDENCE IN THIS OCCURRING.

ECMWF...

THE EURO IS MUCH SLOWER AND ACTUALLY KEEPS THE LOW TO OUR SOUTH
LONGER.  THIS WOULD HELP TO ROUTE MORE WATER OUT OF THE FLOW.
EVENTUALLY ON TUESDAY...THE LOW LIFTS THROUGH THE AREA AND HAS LOWER
...LESS THAN AN INCH QPF...ALONG WITH IT.  THIS WOULD BE A MUCH
BETTER SOLUTION FROM A HYDRO POINT OF VIEW.  MY CONFIDENCE IS
SLIGHTLY HIGHER IN THIS SCENARIO THAN THE GFS...NONETHELESS IT IS
LOW.

THE BOTTOM LINE...

IM STRUGGLING TO DEVELOP THE CONFIDENCE TO TOTALLY ELIMINATE THE GFS
SOLUTION FROM NEXT WEEK. THE GFS HAS CONSISTENTLY DROPPED 1 TO 2
INCHES OF QPF ACROSS CENTRAL MO. A SMALL SHIFT NORTH INTO OUR AREA
IS NOT UNREASONABLE. HOWEVER...IT HAS JUMPED AROUND A LOT MORE
THAN THE EURO AS OF LATE. THIS IS WHY I AM OKAY WITH THE BLEND
THAT I HAVE. UNTIL THE MODELS AGREE ON A SOLUTION THIS WILL
CONTINUE. OBVIOUSLY THESE DIFFERENCES IN SOLUTION MEAN A MAJOR
DIFFERENCE IN POTENTIAL IMPACTS. WHILE I DONT WANT TO MINIMALIZE
THESE IMPACTS...IT IS IMPORTANT TO REMEMBER WE ARE ALMOST 7 DAYS
OUT. EXPECT CHANGES TO THE FORECAST FOR EARLY NEXT WEEK...SOME OF
THESE CHANGES COULD BE SIGNIFICANT...THAT IS THE BOTTOM LINE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1215 PM CST TUE DEC 22 2015

IFR CONDS GRADUALLY IMPROVING TO MVFR LATE THIS AFTERNOON INTO
THIS EVENING. THEN AN INTENSE STORM SYSTEM TRACKING OUT OF THE
SOUTHERN PLAINS WILL SPREAD RAIN AND IFR CONDS INTO THE AREA LATE
TONIGHT AND ON WEDNESDAY. SCATTERED THUNDERSTORMS ARE ALSO
EXPECTED MAINLY IN THE AFTERNOON. SOUTHEAST WINDS 10 TO 15 KNOTS
THROUGH THIS TAF CYCLE.

&&

.HYDROLOGY...
ISSUED AT 247 AM CST TUE DEC 22 2015

RAINFALL AMOUNTS OF A QUARTER INCH TO THREE QUARTERS OF AN INCH FELL
OVER THE PAST 24 HOURS GENERALLY SOUTH OF A LINE FROM MARENGO TO
BELLEVUE. WITH SATURATED GROUND...NEARLY ALL OF THIS RAINFALL WILL
BE RUNOFF AND HAVE ALREADY SEEN SOME LOCAL RESPONSES ON SOME OF THE
RIVERS. THIS ADDITIONAL RAINFALL WILL INCREASE THE FORECAST CRESTS A
BIT ON SOME RIVERS...AND HAS PUSHED THE FORECASTS FOR THE LOWER END
OF THE SKUNK AND DES MOINES RIVERS OVER FLOOD STAGE. ALONG THE
MISSISSIPPI...AFTER SEEING THE RIVER LEVELS FALL OR BECOME STEADY
OVER THE PAST 24 HOURS...MOST SITES WILL SEE THE RIVER BEGIN RISING
AGAIN...WITH THIS TREND CONTINUING THROUGH MUCH OF THE WEEK.

MOST FORECASTS ARE FOR THE RIVER LEVELS TO FALL BY THE END OF THIS
WEEK. HOWEVER...ADDITIONAL STORM SYSTEMS ARE LOOKING TO PASS ACROSS
THE AREA THROUGH THE NEXT WEEK WITH PRECIPITATION FALLING AS RAIN.
THE FIRST OF WHICH WILL BE WEDNESDAY. THERE IS QUITE A BIT OF
UNCERTAINTY IN HOW MUCH RAIN WILL FALL AND WHAT AREAS WILL GET HIT
YET...BUT LIKELY WILL BE ADDITIONAL RISES AND FURTHER POTENTIAL FOR
FLOODING ON SOME AREA RIVERS THROUGH THE CHRISTMAS HOLIDAY WEEKEND.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

UPDATE...HAASE
SYNOPSIS...MCCLURE
SHORT TERM...MCCLURE
LONG TERM...GIBBS
AVIATION...HAASE
HYDROLOGY...GIBBS




AREA FORECAST DISCUSSION

NWS JACKSON MS

 414 PM CST TUE DEC 22 2015

...SIGNIFICANT SEVERE WEATHER POSSIBLE ON WEDNESDAY...

.DISCUSSION...WIDESPREAD STRATUS CONTINUE TO MAINTAIN GRIP OVER THE
AREA THIS AFTERNOON. A FEW BREAKS WERE NOTED ON VISIBLE SAT,
ALLOWING A FEW LOCATIONS TO WARM INTO THE LOWER 70S. HOWEVER, MOST
SITES REMAINED IN THE MID TO UPPER 60S AS OF 21Z. THE ENVIRONMENT WAS
ALREADY RATHER MOIST, WITH DEWPOINTS IN THE MID TO UPPER 60S
AREAWIDE. CONSIDERABLE GULF COASTAL CONVECTION HAS DEVELOPED TODAY
IN THE INTERFACE BETWEEN A RIGHT ENTRANCE REGION OF THE POLAR JET
AND LEFT EXIT REGION OF THE SUBTROPICAL JET. SOME OF THIS ACTIVITY
HAS ALREADY BEGUN WORKING INTO SE MISSISSIPPI, WITH ADDITIONAL
CONVECTION EXPECTED TO LIFT MAINLY INTO SOUTHEASTERN PORTIONS OF THE
CWA THROUGH THE EVENING.

LOOKING BACK TO THE WEST, U/A ANALYSIS SHOWS A DIP IN THE POLAR JET
OVER THE ROCKY MTNS WHICH IS LEADING TO A DEVELOPING LEESIDE LOW
OVER THE SOUTHERN HIGH PLAINS. AS AN UPPER JET MAX CURRENTLY
EXTENDING FROM OREGON THROUGH NV/UT/AZ ENTERS THE BASE OF THIS
TROUGH, IT WILL TAKE ON A NEGATIVE TILT EARLY WED MORNING OVER THE
PLAINS AS THE SURFACE LOW TRACKS NEWD THROUGH THE MISSOURI VALLEY
TOWARD THE GREAT LAKES THROUGH THE DAY. EARLY WED MORNING, AS THE
COASTAL CONVECTION BEGINS TO LIFT INLAND, THIS WILL USHER IN A SURGE
OF LOW LEVEL MOISTURE/THETA-E THROUGH THE DAY. SOME HIGH RES GUIDANCE
SUGGESTS SCATTERED CONVECTION WILL BE ONGOING AROUND DAYBREAK ON THE
NOSE OF THIS MOISTURE/INSTABILITY SURGE. WHILE THIS CONVECTION WOULD
LIKELY BE ELEVATED, RESPECTABLE FORECAST MID LEVEL LAPSE RATES
SUGGEST LARGE HAIL IS POSSIBLE DURING THE MORNING WITH ANY ACTIVITY
LIFTING NORTHWARD ACROSS THE REGION.

THERE MAY BE A BIT OF A BREAK IN THE ACTION BETWEEN NORTHWARD MOVING
MORNING ACTIVITY AND MORE SUBSTANTIAL DEVELOPMENT DURING THE
AFTERNOON AS A WEAK CAPPING INVERSION HOLDS OFF SURFACE BASED
DEVELOPMENT FOR A WHILE. THEN BY THE AFTERNOON, BETTER UPPER HEIGHT
FALLS AND DECENT MID LEVEL LAPSE RATES WILL OVERLAY DEWPOINTS IN THE
UPPER 60S TO NEAR 70 AND MLCAPES IN THE 1000-2000 J/KG RANGE (IF NOT
HIGHER AS SUGGESTED BY SOME HIGH-RES GUIDANCE). EVEN WITH
CONSIDERABLE CLOUD COVER, WAA AND LIMITED INSOLATION SHOULD BE
SUFFICIENT TO BREAK THE CAP, ALLOWING SCATTERED SUPERCELLS TO DEVELOP
IN AN ENVIRONMENT CHARACTERIZED BY DEEP LAYER SHEAR OF 50-70 KT AND
EFFECTIVE SR HELICITY VALUES IN THE 200-400 M2/S2 RANGE. ALL MODES OF
SEVERE WX WILL BE POSSIBLE, INCLUDING TORNADOES. THE SREF SIG TOR
INGREDIENTS PARAMETER ALSO SUGGESTS SOME STRONG TORNADOES ARE
POSSIBLE, PARTICULARLY OVER THE NORTHERN HALF OF THE CWA. AT THIS
TIME, OUR AREA OF GREATEST CONCERN IS AN AREA ROUGHLY NORTH OF A LINE
FROM RAYVILLE LA TO YAZOO CITY TO MACON, AS THIS IS WHERE THE BEST
UPPER SUPPORT (HEIGHT FIELD/HEIGHT FALLS/PROXIMITY TO PASSING
SHORTWAVE) WILL EXIST. CONFIDENCE IN SEVERE WEATHER IS LOWER SOUTH OF
THIS LINE, BUT THE THREAT CERTAINLY STILL EXISTS.

HEADING LATER INTO THE NIGHT AND EARLY MORNING HOURS THURSDAY, THE
SEVERE THREAT BECOMES MORE QUESTIONABLE AS UPPER HEIGHTS AND SURFACE
PRESSURES BEGIN TO RISE. HOWEVER THERE WILL REMAIN A SURGE OF LOW
LEVEL INSTABILITY AND LINGERING LOW LEVEL SHEAR ACROSS MAINLY EASTERN
MS, SO THERE IS SOME POSSIBILITY SEVERE COULD CONTINUE WELL INTO THE
OVERNIGHT.

A SECONDARY CONCERN THAT MAY REQUIRE MONITORING IS HEAVY RAINFALL
POTENTIAL. RECENT RUNS OF THE NAM HAVE POINTED TO SOME POTENTIAL FOR
CORRIDORS OF TRAINING STORMS. WHILE THIS IS NOT REFLECTED IN THE
LARGER SCALE QPF, WHICH AVERAGES OUT WITH AREAS RECEIVING MUCH LESS
RAIN, THIS WILL BE ANOTHER POTENTIAL HAZARD TO MONITOR WEDNESDAY INTO
EARLY THURSDAY.

AN ACTIVE WEATHER PATTERN WILL CONTINUE INTO THE END OF THE WEEK AS
THE POLAR JET REMAINS NORTH OF THE AREA AND NO FROPA OCCURS WITH THE
MIDWEEK SYSTEM. THOUGH THERE WILL BE A BRIEF DROP OFF IN COLUMN
MOISTURE ACROSS MUCH OF THE AREA ALONG A PREFRONTAL TROUGH (EXCEPT
THE PINE BELT WHERE POSITIVE PW ANOMALIES WILL REMAIN), LOW LEVEL
FLOW WILL QUICKLY BRING A RETURN OF 1.5-2 INCH PW ACROSS MUCH OF THE
AREA THURSDAY INTO CHRISTMAS DAY. RELEVANT PORTIONS OF THE PREVIOUS
LONG TERM FOLLOW BELOW... /DL/

MODEL CONSENSUS HAS THE BOUNDARY JUST NORTHWEST OF OUR CWA BY NOON
FRIDAY RESULTING IN PWATS GREATER THAN AN INCH AND A HALF OVER OUR
WHOLE CWA. GREATEST POPS WL BE CARRIED OVER OUR NORTHWEST ZONES
FRIDAY BUT THERE WL BE A CHANCE FOR RAIN AREAWIDE. THE DEEPENING
TROUGH OVER THE WESTERN CONUS WILL CLOSE OFF OVER THE DESERT
SOUTHWEST BY SATURDAY MORNING AND SWING EAST TO THE TEXAS BIG BEND
REGION BY SUNDAY MORNING. THE MODELS BEGIN TO DIVERGE WITH THE TRACK
OF THE CLOSED LOW SUNDAY INTO TUESDAY WITH THE GFS BEING THE MOST
PROGRESSIVE AND FASTEST BRINGING THE ASSOCIATED COLD FRONT ACROSS OUR
CWA SUNDAY NIGHT. THE ECMWF IS THE SLOWEST WITH THE CLOSED LOW AND
BRINGS THE ASSOCIATED CLOD FRONT THROUGH OUR CWA MONDAY NIGHT. BOTH
MODELS AGREE THAT WARMER THAN NORMAL TEMPERATURES WITH MOSTLY
DIURNALLY DRIVEN RAIN CHANCES WILL CONTINUE OVER OUR CWA THROUGH THE
WEEKEND. HAVE USED A BLEND AND LEANED TOWARD A LITTLE SLOWER FROPA IN
LINE WITH CONSENSUS FROM MONDAY`S RUNS WITH MONDAY BEING THE MAIN
RAIN DAY. THERE STILL REMAIN INDICATION OF SOME POTENTIAL FOR SEVERE
STORMS ALONG AND AHEAD OF THE FRONT. /22/

&&

.AVIATION...LATEST HRRR GUIDANCE INDICATES AT LEAST IFR IF NOT LIFR
STRATUS WILL REMAIN THROUGH TONIGHT. SHRA/TSRA CHANCES WILL INITIALLY
INCREASE OVER THE MEI/PIB AREA THIS AFTN...AND THEN INCREASE LATE
TONIGHT OVER THE REMAINING AREA AS SOUTHERLY FLOW RAPIDLY
STRENGTHENS. SEVERE TSRA WILL BE POSSIBLE WED INTO WED EVNG. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       64  76  65  77 /  50  81  48  44
MERIDIAN      63  75  68  77 /  76  72  62  59
VICKSBURG     65  77  64  77 /  52  77  36  28
HATTIESBURG   64  77  70  78 /  86  67  60  58
NATCHEZ       66  78  64  78 /  60  75  32  35
GREENVILLE    65  75  60  74 /  51  86  33  13
GREENWOOD     65  77  62  77 /  41  85  44  22

&&

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

$$

DL/EC/22




AREA FORECAST DISCUSSION

NWS JACKSON MS

 413 PM CST TUE DEC 22 2015

...SIGNIFICANT SEVERE WEATHER POSSIBLE ON WEDNESDAY...

.DISCUSSION...WIDESPREAD STRATUS CONTINUE TO MAINTAIN GRIP OVER THE
AREA THIS AFTERNOON. A FEW BREAKS WERE NOTED ON VISIBLE SAT,
ALLOWING A FEW LOCATIONS TO WARM INTO THE LOWER 70S. HOWEVER, MOST
SITES REMAINED IN THE MID TO UPPER 60S AS OF 21Z. THE ENVIRONMENT WAS
ALREADY RATHER MOIST, WITH DEWPOINTS IN THE MID TO UPPER 60S
AREAWIDE. CONSIDERABLE GULF COASTAL CONVECTION HAS DEVELOPED TODAY IN
THE INTERFACE BETWEEN A RIGHT ENTRACE REGION OF THE POLAR JET AND
LEFT EXIT REGION OF THE SUBTROPICAL JET. SOME OF THIS ACTIVITY HAS
ALREADY BEGUN WORKING INTO SE MISSISSIPPI, WITH ADDITIONAL CONVECTION
EXPECTED TO LIFT MAINLY INTO SOUTHEASTERN PORTIONS OF THE CWA
THROUGH THE EVENING.

LOOKING BACK TO THE WEST, U/A ANALYSIS SHOWS A DIP IN THE POLAR JET
OVER THE ROCKY MTNS WHICH IS LEADING TO A DEVELOPING LEESIDE LOW
OVER THE SOUTHERN HIGH PLAINS. AS AN UPPER JET MAX CURRENTLY
EXTENDING FROM OREGON THROUGH NV/UT/AZ ENTERS THE BASE OF THIS
TROUGH, IT WILL TAKE ON A NEGATIVE TILT EARLY WED MORNING OVER THE
PLAINS AS THE SURFACE LOW TRACKS NEWD THROUGH THE MISSOURI VALLEY
TOWARD THE GREAT LAKES THROUGH THE DAY. EARLY WED MORNING, AS THE
COASTAL CONVECTION BEGINS TO LIFT INLAND, THIS WILL USHER IN A SURGE
OF LOW LEVEL MOISTURE/THETA-E THROUGH THE DAY. SOME HIGH RES GUIDANCE
SUGGESTS SCATTERED CONVECTION WILL BE ONGOING AROUND DAYBREAK ON THE
NOSE OF THIS MOISTURE/INSTABILITY SURGE. WHILE THIS CONVECTION WOULD
LIKELY BE ELEVATED, RESPECTABLE FORECAST MID LEVEL LAPSE RATES
SUGGEST LARGE HAIL IS POSSIBLE DURING THE MORNING WITH ANY ACTIVITY
LIFTING NORTHWARD ACROSS THE REGION.

THERE MAY BE A BIT OF A BREAK IN THE ACTION BETWEEN NORTHWARD MOVING
MORNING ACTIVITY AND MORE SUBSTANTIAL DEVELOPMENT DURING THE
AFTERNOON AS A WEAK CAPPING INVERSION HOLDS OFF SURFACE BASED
DEVELOPMENT FOR A WHILE. THEN BY THE AFTERNOON, BETTER UPPER HEIGHT
FALLS AND DECENT MID LEVEL LAPSE RATES WILL OVERLAY DEWPOINTS IN THE
UPPER 60S TO NEAR 70 AND MLCAPES IN THE 1000-2000 J/KG RANGE (IF NOT
HIGHER AS SUGGESTED BY SOME HIGH-RES GUIDANCE). EVEN WITH
CONSIDERABLE CLOUD COVER, WAA AND LIMITED INSOLATION SHOULD BE
SUFFICIENT TO BREAK THE CAP, ALLOWING SCATTERED SUPERCELLS TO DEVELOP
IN AN ENVIRONMENT CHARACTERIZED BY DEEP LAYER SHEAR OF 50-70 KT AND
EFFECTIVE SR HELICITY VALUES IN THE 200-400 M2/S2 RANGE. ALL MODES OF
SEVERE WX WILL BE POSSIBLE, INCLUDING TORNADOES. THE SREF SIG TOR
INGREDIENTS PARAMETER ALSO SUGGESTS SOME STRONG TORNADOES ARE
POSSIBLE, PARTICULARLY OVER THE NORTHERN HALF OF THE CWA. AT THIS
TIME, OUR AREA OF GREATEST CONCERN IS AN AREA ROUGHLY NORTH OF A LINE
FROM RAYVILLE LA TO YAZOO CITY TO MACON, AS THIS IS WHERE THE BEST
UPPER SUPPORT (HEIGHT FIELD/HEIGHT FALLS/PROXIMITY TO PASSING
SHORTWAVE) WILL EXIST. CONFIDENCE IN SEVERE WEATHER IS LOWER SOUTH OF
THIS LINE, BUT THE THREAT CERTAINLY STILL EXISTS.

HEADING LATER INTO THE NIGHT AND EARLY MORNING HOURS THURSDAY, THE
SEVERE THREAT BECOMES MORE QUESTIONABLE AS UPPER HEIGHTS AND SURFACE
PRESSURES BEGIN TO RISE. HOWEVER THERE WILL REMAIN A SURGE OF LOW
LEVEL INSTABILITY AND LINGERING LOW LEVEL SHEAR ACROSS MAINLY EASTERN
MS, SO THERE IS SOME POSSIBILITY SEVERE COULD CONTINUE WELL INTO THE
OVERNIGHT.

A SECONDARY CONCERN THAT MAY REQUIRE MONITORING IS HEAVY RAINFALL
POTENTIAL. RECENT RUNS OF THE NAM HAVE POINTED TO SOME POTENTIAL FOR
CORRIDORS OF TRAINING STORMS. WHILE THIS IS NOT REFLECTED IN THE
LARGER SCALE QPF, WHICH AVERAGES OUT WITH AREAS RECEIVING MUCH LESS
RAIN, THIS WILL BE ANOTHER POTENTIAL HAZARD TO MONITOR WEDNESDAY INTO
EARLY THURSDAY.

AN ACTIVE WEATHER PATTERN WILL CONTINUE INTO THE END OF THE WEEK AS
THE POLAR JET REMAINS NORTH OF THE AREA AND NO FROPA OCCURS WITH THE
MIDWEEK SYSTEM. THOUGH THERE WILL BE A BRIEF DROP OFF IN COLUMN
MOISTURE ACROSS MUCH OF THE AREA ALONG A PREFRONTAL TROUGH (EXCEPT
THE PINE BELT WHERE POSITIVE PW ANOMALIES WILL REMAIN), LOW LEVEL
FLOW WILL QUICKLY BRING A RETURN OF 1.5-2 INCH PW ACROSS MUCH OF THE
AREA THURSDAY INTO CHRISTMAS DAY. RELEVANT PORTIONS OF THE PREVIOUS
LONG TERM FOLLOW BELOW... /DL/

MODEL CONSENSUS HAS THE BOUNDARY JUST NORTHWEST OF OUR CWA BY NOON
FRIDAY RESULTING IN PWATS GREATER THAN AN INCH AND A HALF OVER OUR
WHOLE CWA. GREATEST POPS WL BE CARRIED OVER OUR NORTHWEST ZONES
FRIDAY BUT THERE WL BE A CHANCE FOR RAIN AREAWIDE. THE DEEPENING
TROUGH OVER THE WESTERN CONUS WILL CLOSE OFF OVER THE DESERT
SOUTHWEST BY SATURDAY MORNING AND SWING EAST TO THE TEXAS BIG BEND
REGION BY SUNDAY MORNING. THE MODELS BEGIN TO DIVERGE WITH THE TRACK
OF THE CLOSED LOW SUNDAY INTO TUESDAY WITH THE GFS BEING THE MOST
PROGRESSIVE AND FASTEST BRINGING THE ASSOCIATED COLD FRONT ACROSS OUR
CWA SUNDAY NIGHT. THE ECMWF IS THE SLOWEST WITH THE CLOSED LOW AND
BRINGS THE ASSOCIATED CLOD FRONT THROUGH OUR CWA MONDAY NIGHT. BOTH
MODELS AGREE THAT WARMER THAN NORMAL TEMPERATURES WITH MOSTLY
DIURNALLY DRIVEN RAIN CHANCES WILL CONTINUE OVER OUR CWA THROUGH THE
WEEKEND. HAVE USED A BLEND AND LEANED TOWARD A LITTLE SLOWER FROPA IN
LINE WITH CONSENSUS FROM MONDAY`S RUNS WITH MONDAY BEING THE MAIN
RAIN DAY. THERE STILL REMAIN INDICATION OF SOME POTENTIAL FOR SEVERE
STORMS ALONG AND AHEAD OF THE FRONT. /22/

&&

.AVIATION...LATEST HRRR GUIDANCE INDICATES AT LEAST IFR IF NOT LIFR
STRATUS WILL REMAIN THROUGH TONIGHT. SHRA/TSRA CHANCES WILL INITIALLY
INCREASE OVER THE MEI/PIB AREA THIS AFTN...AND THEN INCREASE LATE
TONIGHT OVER THE REMAINING AREA AS SOUTHERLY FLOW RAPIDLY
STRENGTHENS. SEVERE TSRA WILL BE POSSIBLE WED INTO WED EVNG. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       64  76  65  77 /  50  81  48  44
MERIDIAN      63  75  68  77 /  76  72  62  59
VICKSBURG     65  77  64  77 /  52  77  36  28
HATTIESBURG   64  77  70  78 /  86  67  60  58
NATCHEZ       66  78  64  78 /  60  75  32  35
GREENVILLE    65  75  60  74 /  51  86  33  13
GREENWOOD     65  77  62  77 /  41  85  44  22

&&

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

$$

DL/EC/22




AREA FORECAST DISCUSSION...CORRECTED

NWS JACKSON MS

 1053 AM CST TUE DEC 22 2015

...CONFIDENCE INCREASING IN SEVERE WEATHER THREAT ON WEDNESDAY...

.DISCUSSION...BUSY MORNING IN THE WX OFFICE WITH MUCH TO DISCUSS.
FIRST THINGS FIRST, THE DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE.
VISIBILITY AT ALMOST ALL SITES HAS IMPROVED TO ABOVE 1/4, WITH THE
LAST EXCEPTIONS BEING OUR TWO SITES IN JONES COUNTY. STILL,
CONSIDERABLE FOG AND LOW STRATUS REMAIN ACROSS MOST OF THE CWA, SO
THIS WAS ADDED TO THE FORECAST FOR THE REMAINDER OF THE MORNING. THE
FOG AND LOW CLOUDS ARE STUNTING TEMP RISES ACROSS THE AREA, AND THUS
MAX TEMPS HAVE BEEN ADJUSTED DOWNWARD ACCORDINGLY ACROSS THE ENTIRE
CWA.

NOW, LOOKING AHEAD TO WED...MODELS CONTINUE TO SHOW AN IMPRESSIVE
COMBINATION OF SHEAR AND INSTABILITY AHEAD OF AN APPROACHING STORM
SYSTEM. WHILE MORE SUBTLE HEIGHT FALLS MAY WELL PRECLUDE MORE
WIDESPREAD CONVECTION THROUGH THE EVENT, CURRENT PARAMETER SPACING
SUGGESTS THAT THE STORMS THAT DO DEVELOP COULD GET RATHER NASTY.
CURRENT THINKING IS THE WINDOW OF GREATEST CONCERN WILL BE THE
AFTERNOON AND EARLY EVENING WED OVER NORTHERN PORTIONS OF THE
CWA...WHEN MID/UPPER HEIGHT FALLS WILL BE GREATEST AND SURFACE BASED
PARCELS WILL BE MOST LIKELY TO OVERCOME THE CAP. AT THAT POINT,
SCATTERED SUPERCELL DEVELOPMENT LOOKS QUITE POSSIBLE. ALSO OF
NOTE...RECENT HIGH RES GUIDANCE RUNS SUGGEST THE POTENTIAL FOR
ELEVATED CONVECTION EARLIER IN THE MORNING, WITH POTENTIAL FOR LARGE
HAIL ACROSS SOUTHERN PORTIONS OF THE CWA.

AGAIN...WHILE THERE REMAIN SOME QUESTIONS ABOUT COVERAGE/HOW
WIDESPREAD OF AN AREA WILL BE IMPACTED, THE POTENTIAL FOR HIGHER END
SEVERE WX, INCLUDING POSSIBLY A COUPLE STRONG TORNADOES, WARRANTS A
CATEGORY INCREASE IN SEVERE WEATHER POTENTIAL IN OUR HWO/GRAPHICS.
WE WILL GO AHEAD AND MAKE THESE CHANGES THIS MORNING. MORE
DETAILS WILL BE COMING UP THIS AFTERNOON. /DL/

&&

.AVIATION...WHILE THERE WILL BE GRADUAL IMPROVEMENT WITH THE VSBYS
DUE TO FOG AS WE GO THROUGH THE REMAINDER OF THE MORNING INTO THE
EARLY AFTN...LATEST HRRR GUIDANCE INDICATES AT LEAST IFR IF NOT LIFR
STRATUS WILL REMAIN THROUGH TONIGHT. SHRA/TSRA CHANCES WILL
INITIALLY INCREASE OVER THE MEI/PIB AREA THIS AFTN...AND THEN
INCREASE LATE TONIGHT OVER THE REMAINING AREA AS SOUTHERLY FLOW
RAPIDLY STRENGTHENS. SEVERE TSRA WILL BE POSSIBLE WED INTO WED EVNG.
/EC/

&&

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

$$

DL/EC/15/22




AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 1144 AM CST TUE DEC 22 2015

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

FORECAST CONCERNS WILL BE POTENTIAL FOR MIXED PRECIPITATION/RAIN/
SNOW THROUGH THE THURSDAY.

LARGE SCALE PATTERNS HAS AN H5 TROUGH ENCOMPASSING MUCH OF THE
U.S. THIS MORNING WITH SHORTWAVE TROUGH ENERGY EMBEDDED IN THE
FLOW OVER THE NORTHERN ROCKIES MOVING INTO THE WESTERN HIGH
PLAINS. LIGHTNING STRIKES WERE NOTED OVER PARTS OF NORTHERN UTAH
AND WYOMING. THIS SHORTWAVE TROUGH WILL ROTATE THROUGH...MAINLY
AFFECTING THE DAKOTAS. THIS WEATHER SYSTEM WILL SPREAD
ACCUMULATING SNOW ACROSS A LARGE PART OF NORTH DAKOTA...NORTH OF
THE TRACK OF THE SURFACE LOW. WATER VAPOR SATELLITE IMAGERY SHOWS
INCREASING HIGHER LEVEL MOISTURE ADVANCING EASTWARD FROM THE WEST
ASSOCIATED WITH A STRONG 160KT H3 JET MOVING INTO THE WEST COAST.

THE LOW LEVEL JET FROM CENTRAL NEBRASKA THROUGH CENTRAL KANSAS
WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA AND INCREASE
TO 50KTS. THIS WILL HELP BREAK UP THE LOW CLOUDS (AND FOG) MIXING
IN SOME OF THE DRY AIR ALOFT. SOUTH WINDS WILL INCREASE TO 15 TO
30 MPH. MID AND HIGH CLOUDS CAN BE EXPECTED THROUGHOUT THE DAY.
H85 TEMPERATURES INCREASE TO +6-+8 DEG C. WARMER HIGHS IN THE 40S
TO LOWER 50S ARE FORECAST.

TONIGHT...THE FRONTAL SYSTEM BECOMES COMPLEX...WITH SURFACE LOW
PRESSURE OVER COLORADO MOVING INTO KANSAS AND THE COLD FRONT
APPROACHES FROM THE WEST WITH THE NORTHERN SYSTEM. BY 06Z AN
INVERTED TROF SHOULD EXTEND NEAR LINCOLN TOWARD SIOUX CITY...WITH
MILD AIR ON THE EAST SIDE OF THE FRONT AND COOLER AIR TO THE WEST.
THERE ARE STILL SOME DIFFERENCES IN THE MODELS AS TO THE EFFECTS
OF THE NORTHERN STREAM SYSTEM AND THE SOUTHERN STREAM SYSTEM.
THERE MAY BE TWO BANDS OF MORE FOCUSED PRECIPITATION WITH LIGHTER
PRECIPITATION IN BETWEEN. BETWEEN 06Z-12Z...THE PRECIPITATION
SHOULD EXPAND IN THESE TWO AREAS. THE GFS DOES NOT REALLY SHOW A
MIX OF PRECIP...HOWEVER THE HRRR EXP/NAM DO HAVE MIXED OF
PRECIPITATION. DO MENTION A MIX ON THE WESTERN PARTS OF THE PRECIP
AREA WITH RAIN WHERE THIS IS SUPPORTED...CONTINUING INTO WEDNESDAY
MORNING...BEFORE MOVING OUT IN THE AFTERNOON. THE 06Z MODELS ARE
COMING IN A LITTLE SLOWER...SO THE TIMING MAY NEED TO BE ADJUSTED.
HIGHS WEDNESDAY SHOULD BE IN THE LOWER 30S TO MID 40S NEAR THE
KANSAS BORDER.

THIS ACTIVE PATTERN CONTINUES WITH A SHORTWAVE MOVING THROUGH LATE
WEDNESDAY NIGHT AND THURSDAY. PRELIMINARY TEMPERATURES APPEAR TO
SUPPORT A MAINLY LIGHT SNOW EVENT. THE NAM IS MORE INTENSE WITH
THIS SHORTWAVE...FARTHER NORTH AND LASTS INTO THE AFTERNOON. FOR
NOW HAVE SOME LIGHT SNOW AMOUNTS MENTIONED.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 22 2015

THERE ARE STILL SIGNIFICANT DIFFERENCES IN THE EXTENDED. WE
CONTINUE TO MENTION RAIN/SNOW FOR FRIDAY AS A STRONGER TROUGH
MOVES INTO UTAH/WYOMING/COLORADO. THE STORM SYSTEM CLOSES OFF OVER
ARIZONA FRIDAY NIGHT WITH WEAK FORCING OVER THE AREA. A TROUGH IN
THE NORTHERN PLAINS REINFORCES THE COLD AIR A LITTLE FARTHER SOUTH
SATURDAY. THE LARGER DIFFERENCES ARE FOR SUNDAY AND MONDAY WITH
THE GFS TRACK OF THE CLOSED LOW MUCH FARTHER NORTH OVER KANSAS
CITY COMPARED TO THE EC...STILL OVER TEXAS.THE GFS HAS MORE
PRECIP WHILE THE EC IS MORE DRY FOR NEB/IA. UNTIL THERE IS BETTER
AGREEMENT...WE STILL HAVE PRECIP CHANCES MENTIONED IN THESE
PERIODS. TEMPERATURES REMAIN AT OR ABOVE NORMAL FOR THIS TIME OF
YEAR.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1137 AM CST TUE DEC 22 2015

VFR CONDITIONS WITH GUSTY SOUTHEAST 15 TO 25KT WILL PERSIST
THROUGH 00Z BEFORE WINDS DIMINISH TO LESS THAN 10KT. DETERIORATING
CONDITIONS ARE FORECAST AFTER 06Z WITH CIGS DROPPING TO MVFR AT
KOMA AND KLNK. RAIN WILL ALSO DEVELOP BY 10Z WHEN IFR TO LIFR
CONDITIONS ARE FORECAST BOTH VSBYS AND CIGS AT KOMA AND KLNK. THE
RAIN AND WORST AVIATION WEATHER LOOKS TO STAY SOUTHEAST OF KOFK
THROUGH THE EVENT...WITH MVFR CIGS FORECAST THERE. NORTH WINDS OF
15 TO 25KT ARE ALSO EXPECTED AT ALL EASTERN NEBRASKA TAF SITES BY
12Z OR SO.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...DERGAN




AREA FORECAST DISCUSSION

NWS RALEIGH NC

 315 PM EST TUE DEC 22 2015

.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT THROUGH TONIGHT...THEN BE OVERTAKEN BY A MARITIME WARM
FRONT THAT WILL SURGE ACROSS THE CAROLINAS AND VIRGINIA ON
WEDNESDAY. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 PM TUESDAY...

...HEAVY RAIN AND SOME LOCALIZED FLOODING POSSIBLE OVER THE WESTERN
PIEDMONT LATE TONIGHT INTO WEDNESDAY...

EARLIER RAINFALL IS NOW NEAR THE COAST AS THE ASSOCIATED SHEAR AXIS
AND DEEPEST MOISTURE HAVE SHIFTED EAST.  SLIGHTLY DRIER MID LEVEL
AIR...WHICH HAS AIDED PERIODS OF DENSE FOG IN THE WEDGE AIRMASS
OVER THE WESTERN PIEDMONT...WILL GIVE WAY TO ANOTHER SURGE OF DEEP
MOISTURE ACCOMPANYING ANOTHER WAVE IN THE SOUTHWEST FLOW.  PW WILL
INCREASE BACK TO NEAR 1.8 INCHES...WHICH IS NEARLY A CLIMATOLOGICAL
MAX FOR THIS TIME OF YEAR. WHILE THE MAIN AMPLIFICATION OF THE UPPER
TROUGH MOVING OUT OF THE SOUTHERN US WILL BE WELL WEST OF HERE... A
NOTABLE SHORTWAVE CURRENTLY OVER THE LOWER MISSISSIPPI VALLEY IS
FORECAST TOP LIFT ALONG THE SPINE OF THE APPALACHIANS AND SERVE AS A
FOCUS FOR HEAVY RAINFALL.  THE WESTERN PIEDMONT LIES ON THE EAST
EDGE OF THE GENERAL MODEL CONSENSUS OF 2+ INCHES OF QPF...BUT GIVEN
THE ANOMALIES IN THIS PATTERN AND THE 1-2 INCHES THAT FEEL LAST
NIGHT...A FLASH FLOOD WATCH WILL BE ISSUED STARTING AT MIDNIGHT
TONIGHT FOR THE WESTERN PIEDMONT.  PRIOR TO THE RAIN...THE HRRR SHOWS
WIDESPREAD FOG SETTLING BACK IN WITHIN THE WEDGE AIRMASS.  A DENSE
FOG ADVISORY MAY BE NEEDED BEFORE PRECIP SPREADS IN FROM THE SOUTH
AND HELPS TO AT LEAST MIX OUT THE 1/4 MILE VSBYS.  TEMPS WILL HOLD
STEADY OR RISE LATE TONIGHT WITH THE STRENGTHENING WARM
ADVECTION..WITH READINGS IN THE UPPER 50S TO UPPER 60S.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM TUESDAY...

ONGOING PRECIP WEDNESDAY MORNING WILL BE FOCUSED ACROSS THE WESTERN
PIEDMONT AS A DISTURBANCE LIFTS ALONG THE APPALACHIANS.  INCREDIBLY
HIGH PW DISCUSSED INT HE NEAR TERM FORECAST WILL REMAIN OVER THE
AREA WITH NO AIRMASS CHANGE IN SIGHT.  THE FOCUS FOR PRECIP...LIKELY
MORE CONVECTIVE IN NATURE...SHOULD SHIFT EAST DURING THE DAY AS THE
DISTURBANCE LIFTS OFF TO THE NORTH AND A TRAILING SHEAR AXIS MOVES
EAST.  MID-LEVEL LAPSE RATES ARE EXPECTED TO BE WEAK EAST OF THE
APPALACHIANS (THOUGH THE GFS FORECASTS 6+ C/KM)...BUT GIVEN TEMPS
CLIMBING INTO THE MID 70S AND DEWPOINTS APPROACHING 70...FORECAST
SOUNDINGS SHOW A RANGE OF 500-1000 J/KG OF MUCAPE IN THE COASTAL
PLAIN WEDNESDAY AFTERNOON.  EVEN IF THIS IS A LITTLE
OVERDONE...CONVECTION SHOULD BE UNINHIBITED AND COULD TAP INTO THE
40-50KT DEEP SHEAR AND RESULT IN AT LEAST AN ISOLATED SEVERE THREAT.
CONFIDENCE IS LOW GIVEN THE TIME OF YEAR...BUT THE PATTERN IS
UNUSUALLY WARM AND MOIST.  EVEN WITHOUT STRONG STORMS...CONVECTIVE
CELLS WILL BE CAPABLE OF PRODUCING ANOTHER INCH OR MORE OF RAIN IN
ISOLATED AREAS...SO A LOCALIZED FLASH FLOOD THREAT MAY STILL BE
THERE.

THE OVERALL COVERAGE OF PRECIP WILL LESSEN WEDNESDAY NIGHT...THOUGH
MODELS CONTINUE TO SHOW POTENTIAL FOR SOME SCATTERED SHOWERS WELL ON
THROUGH THE NIGHT.  LOWS WILL BE VERY MILD IN THE MID AND UPPER 60S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 200 PM TUESDAY...

THU AND THU NIGHT: STILL SOME DIFFERENCES IN THE MODELS WITH RESPECT
TO RAIN...THUS THERE IS STILL SOME UNCERTAINTY. HOWEVER...IT IS
LOOKING LIKE THURSDAY COULD BE RELATIVELY DRY...BUT WILL KEEP A
CHANCE OF SOME RAIN IN THE FORECAST. RAIN SHOULD NOT BE NEARLY AS
WIDESPREAD AS IN PRECEDING DAYS. BEST CHANCES FOR CONVECTION WILL
BE IN THE NORTHWEST...ESPECIALLY IN THE AFT/EVE AND INTO THE
OVERNIGHT. HIGHEST TEMPERATURES OF THE LONG TERM ARE STILL EXPECTED
ON THURSDAY AS THE SOUTHERLY WARM ADVECTION PEAKS. HIGHS IN THE LOW
TO MID 70S NW TO AROUND 80 DEGREES IN THE SE. LOWS GENERALLY IN THE
MID 60S.

FRI THROUGH SUN: AS OF THE LATEST MEDIUM RANGE MODEL RUNS...THIS
PERIOD WILL LIKELY BE DOMINATED BY SUB-TROPICAL RIDGING ALOFT OVER
THE SOUTHEAST U.S.. SOUTHERLY TO SOUTHWESTERLY RETURN FLOW AROUND
THE SURFACE HIGH WILL CONTINUE TO USHER WARM MOIST AIR INTO THE
REGION...RESULTING IN A VERY WARM AND MOIST PERIOD FOR THIS TIME OF
YEAR. THE OCCASIONAL UPPER LEVEL DISTURBANCE RIDING THE RIDGE MAY
GENERATING ENOUGH LIFT IN THE ANOMALOUSLY WARM MOIST AIRMASS TO KICK
OFF SOME SHOWERS...MAINLY IN THE AFT/EVE HOURS. THE GENERAL PRECIP
TREND FOR THIS PERIOD WILL BE CHARACTERIZED BY A LULL DURING THE
OVERNIGHT AND MORNING HOURS AND HIGHEST CHANCES DURING THE AFT/EVE.
THE INITIAL FRONTAL SURGE THAT WAS ORIGINALLY EXPECTED TO PUSH SOUTH
INTO THE AREA ON FRIDAY WILL LIKELY STAY WELL TO THE NORTH THROUGH
AT LEAST SUNDAY EVENING. LOWS THROUGH THE PERIOD WILL BE FAIRLY
CONSISTENT...AND WELL ABOVE NORMAL...IN THE MID 50S TO LOW 60S.
HIGHS WILL LIKELY FLUCTUATE A BIT MORE...BUT GENERALLY STAY BETWEEN
THE MID 60S AND UPPER 70S...WHICH IS 10-15 DEGREES ABOVE NORMAL FOR
LATE DECEMBER.

MONDAY AND MONDAY NIGHT...THE GFS AND ECMWF VARY ON WHETHER THEY
THINK A SECONDARY SURGE WILL PUSH FAR ENOUGH SOUTH TO MOVE INTO
CENTRAL NC FOR THE BEGINNING OF THE WEEK. WILL HOLD OFF ON MAKING
ANY DRASTIC CHANGES TO THE PREVIOUS FORECAST FOR EARLY NEXT WEEK
UNTIL THERE IS BETTER AGREEMENT ONE WAY OR THE OTHER.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 1250 PM TUESDAY...

WHILE THE PRIMARY AXIS OF PRECIPITATION HAS MOVED EAST TOWARD THE
COAST...A MOIST AIRMASS CONTINUES TO PROMOTE AREA OF LOW CLOUDS
ACROSS MUCH OF CENTRAL NC.  WHERE LOW CLOUDS ARE OBSERVED...MAINLY
BETWEEN KGSO AND KRDU...THEY ARE GENERALLY IN THE IFR RANGE.  FOG
THAT DEVELOPED EARLIER THIS MORNING AT KGSO AND KINT IS HOLDING
STRONG DESPITE A LIGHT SOUTHWESTERLY WIND...THOUGH SOME TRAFFIC
CAMERAS IN THE AREA SUGGEST THIS MIGHT JUST BE A VERY VERY LOW
OVERCAST...BUT NONETHELESS PROBLEMATIC.  EXPECT CONDITIONS WILL
REMAIN FAIRLY STEADY STATE THIS AFTERNOON AND INTO THE EARLY EVENING
HOURS. MODELS THEN SUGGEST FOG ADVECTING ACROSS THE AREA FROM THE
SOUTH AS ANOTHER SURGE OF UNSEASONABLY RICH MOISTURE MOVES IN FROM
THE SOUTH. RAIN WILL BE PREDOMINATE ACROSS THE WESTERN PIEDMONT FOR
MUCH OF THE NIGHT...WHICH SHOULD LIMIT THE FOG FROM STAYING VERY
DENSE THERE...WITH PRECIP EVENTUALLY SHIFTING EAST WEDNESDAY
MORNING.  A FEW THUNDERSTORMS ARE POSSIBLY DURING THE DAY ON
WEDNESDAY..MAINLY EAST...WITH WIND GUSTS IN THE 20-30KT RANGE ALSO
POSSIBLE.

OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
NEXT SURGE OF MOISTURE MOVES OUT OF THE GULF OF MEXICO LATE TONIGHT
THROUGH THURSDAY...WHICH COULD POTENTIALLY PRODUCE EXTENDED PERIODS
OF MODERATE TO HEAVY RAIN...ESPECIALLY ACROSS WESTERN NC. SUB-VFR
CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH MORNING.

&&

.CLIMATE...

HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.

DEC 24:       RECORD MAXIMUM   HIGH MINIMUM
GREENSBORO    71 (1964)        52 (1904)
RALEIGH       75 (1931)        59 (1891)
FAYETTEVILLE  78 (1931)        66 (1990)

DEC 25:       RECORD MAXIMUM   HIGH MINIMUM
GREENSBORO    74 (1955)        58 (1932)
RALEIGH       75 (1955)        63 (1932)
FAYETTEVILLE  79 (1932)        68 (1932)

&&

.RAH WATCHES/WARNINGS/ADVISORIES... NONE.

&&

$$

SYNOPSIS...2
NEAR TERM...22
SHORT TERM...22
LONG TERM...10
AVIATION...CBL/22
CLIMATE...HARTFIELD/BLAES




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 328 PM CST TUE DEC 22 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015

HEAVY SNOW NORTH CENTRAL THROUGH EARLY THIS EVENING HIGHLIGHTS THE
SHORT TERM FORECAST.

AS OF 2130 UTC...A SECONDARY SHORTWAVE EVIDENT ON WATER VAPOR HAS
PROPAGATED NORTHEAST OUT OF NORTH CENTRAL SOUTH DAKOTA INTO SOUTH
CENTRAL NORTH DAKOTA...AS REFLECTED IN THE INTENSIFICATION OF
SNOWFALL ACROSS SOUTH CENTRAL NORTH DAKOTA OVER THE PAST ONE TO
TWO HOURS. THIS WAVE WILL CONTINUE TO PROPAGATE NORTHEAST AND
INTERACT WITH THE TROWAL ACROSS NORTH CENTRAL AND NORTHEAST NORTH
DAKOTA TO CONTINUE TO SUPPORT HEAVY SNOWFALL THROUGH EARLY THIS
EVENING. THE 17-20 UTC HRRR AND RAP ITERATIONS HAVE HANDLED THE
MESOSCALE BANDING OF SNOWFALL WELL THROUGH THE AFTERNOON AND WILL
FOLLOW THEIR SOLUTIONS THROUGH THE EVENING...BLENDED TO THE 12 UTC
GLOBAL SUITE LATE TONIGHT INTO WEDNESDAY MORNING. OVERALL...STORM
TOTAL SNOWFALL ACCUMULATIONS OF 6 TO 8 INCHES REMAIN UNCHANGED FOR
THE TOWNER...RUGBY...BOTTINEAU AND ROLETTE AREAS...WITH LOCALLY
HIGHER AMOUNTS. ELSEWHERE FOR TONIGHT INTO WEDNESDAY
MORNING...LIGHT SNOW IS EXPECTED. THIS IS IN ASSOCIATION WITH THE
WEAKENING TROWAL AND A WAVE CURRENTLY ACROSS NORTH CENTRAL
MONTANA THAT WILL PROPAGATE SOUTHEAST. ADDITIONAL SNOWFALL
ACCUMULATIONS OF AROUND ONE...TO POSSIBLY TWO INCHES ACROSS THE
WEST INTO THE SOUTH CENTRAL ARE FORECAST.


.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015

COOLING TEMPERATURES INTO THE WEEKEND HIGHLIGHT THE EXTENDED
FORECAST.

THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON
A BROAD...UPPER LEVEL WESTERN AND CENTRAL CONUS TROUGH TO BEGIN
THE PERIOD TO POSSIBLY TRANSITION TO SPLIT FLOW BY THE
WEEKEND...POTENTIALLY PLACING THE NORTHERN PLAINS IN NORTHWEST
FLOW ALOFT WITH THE NORTHERN STREAM. THIS SUPPORTS A POSSIBLE COOL
DOWN INTO THE WEEKEND. OVERALL...THE CHRISTMAS TRAVEL OUTLOOK
LOOKS GOOD WITH RATHER QUIET WEATHER.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 253 PM CST TUE DEC 22 2015

IFR CONDITIONS IN SNOW THROUGH WEDNESDAY MORNING EXPECTED AT KMOT.
IFR CONDITIONS EXPECTED AT KBIS THIS AFTERNOON IN LIGHT SNOW...AND
AGAIN LATE TONIGHT INTO WEDNESDAY MORNING. IFR IN LIGHT SNOW
DEVELOPING AT KISN LATE THIS AFTERNOON THROUGH TONIGHT. MVFR TO
IFR CONDITIONS IN STRATUS AT KDIK...WITH LIGHT SNOW POSSIBLE LATE
TONIGHT INTO WEDNESDAY MORNING.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR NDZ004-005-012-
013.

WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ022-
023-025.

&&

$$

SHORT TERM...AYD
LONG TERM...AYD
AVIATION...AYD




AREA FORECAST DISCUSSION

NWS BISMARCK ND

 124 PM CST TUE DEC 22 2015

.UPDATE...
ISSUED AT 114 PM CST TUE DEC 22 2015

UPGRADED BOTTINEAU...ROLETTE...PIECE AND MCHENRY COUNTIES TO A
WINTER STORM WARNING THROUGH 12 UTC WEDNESDAY WITH THIS UPDATE.

RADAR AND SATELLITE TRENDS THROUGH 19 UTC DEPICT A BAND OF HEAVY
SNOW ACROSS THE FAR NORTH CENTRAL...TURTLE MOUNTAINS AND INTO THE
DEVILS LAKE BASIN IN ASSOCIATION WITH A DEVELOPING TROWAL. A
SECONDARY WAVE OBSERVED ACROSS SOUTH CENTRAL NORTH DAKOTA IS
EXPECTED TO PROPAGATE NORTHEAST THROUGH THE AFTERNOON TO CONTINUE
TO SUSTAIN THE HEAVY SNOW THREAT WITH RATES AROUND ONE INCH PER
HOUR. SEE SPC MCD 2025. WITH A CLEAR PIVOT POINT SETTING UP JUST
SOUTHEAST OF MINOT...THE AFOREMENTIONED COUNTIES ARE EXPECTED TO
REMAIN IMPACTED BY MESOSCALE SNOW BANDING THROUGH 22-23 UTC.
THEREAFTER...SNOWFALL INTENSITY WILL DECREASE...YET SNOW WILL CONTINUE
THROUGH THE NIGHT. THE 17-18 UTC HRRR AND RAP ITERATIONS DEPICT
WELL THIS SCENARIO...AND PLACE 0.40 TO 0.60 INCHES OF LIQUID
EQUIVALENT OVER THE WARNING AREA...TRANSLATING TO AROUND 6 TO 8
INCHES OF SNOW.

UPDATE ISSUED AT 929 AM CST TUE DEC 22 2015

WEBCAM TRENDS THROUGH 1520 UTC INDICATE THAT THE 700-900 MB DRY
LAYER HAS NOT YET BEEN SUFFICIENTLY ERODED ACROSS CENTRAL NORTH
DAKOTA FOR SNOWFALL TO REACH THE SURFACE. 15 UTC RAP SOUNDINGS
SUGGESTS THE LAYER WILL QUICKLY SATURATE IN THE 16-17 UTC
TIMEFRAME. OVERALL...THE 12 UTC WRF-NMM/ARW...NAM NEST AND 11-14
UTC HRRR ITERATIONS SUPPORT THE TREND FROM THE 00 AND 06 UTC
GLOBAL SUITES OF A SLIGHT NORTHWARD SHIFT IN THE SNOWBAND TODAY AS
COMPARED TO RUNS YESTERDAY...WITH NOW LESS THAN ONE INCH OF SNOW
EXPECTED FOR BISMARCK/MANDAN.

UPDATE ISSUED AT 646 AM CST TUE DEC 22 2015

NO SIGNIFICANT CHANGES WITH THIS UPDATE OTHER THAN TO BLEND THE
LATEST RADAR TRENDS INTO THE HOURLY POP FORECAST THROUGH 15 UTC.
RADAR ECHOES HAVE BEEN STEADILY INCREASING OVER SOUTH CENTRAL ND
DURING THE LAST 90 MINUTES...AND WHILE NO PRECIPITATION REPORTS
HAVE BEEN RECEIVED YET...THE 12 UTC BISMARCK SOUNDING IS NEARLY
SATURATED ALOFT...SO SNOW SHOULD QUICKLY DEVELOP BY MID MORNING.

NOTE THAT OVERNIGHT RAP AND HRRR SIMULATIONS /INCLUDING THE ESRL
HRRR/ HAVE BEEN INCONSISTENT FROM RUN TO RUN AND WITH THE GLOBAL
MODEL GUIDANCE...ESPECIALLY ON THE WESTERN AND SOUTHERN BOUNDARY
OF EXPECTED SNOWFALL TODAY...SO THE ACCUMULATION FORECAST STAYED
THE SAME WITH THIS UPDATE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CST TUE DEC 22 2015

ACCUMULATING SNOW IS THE MAIN CONCERN IN THE SHORT TERM.

CURRENTLY...THE SURFACE LOW WAS AT THE BORDER OF SOUTHEASTERN
MONTANA AND NORTHEASTERN WYOMING. STRONG SOUTHWESTERLY SURFACE
WINDS WERE NOTED OVER EASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA. THESE SURFACE WINDS WERE INDICATIVE OF A STRONG LOW LEVEL
JET DEPICTED IN THE MODELS AT H925 AND H850. AT UPPER LEVELS...A
STRONG SHORTWAVE WAS CENTERED OVER WYOMING. LIGHT RADAR RETURNS
WERE OVER EASTERN MONTANA INTO NORTHEASTERN WYOMING...BUT
INTENSITIES WERE INCREASING SOUTH AND EAST OF BILLINGS INTO
NORTHEASTERN WYOMING...IN THE VICINITY OF THE UPPER LEVEL
SHORTWAVE.

THE UPPER LEVEL SHORTWAVE IS FORECAST TO MOVE NORTHEAST ACROSS THE
DAKOTAS TODAY AND MOVE INTO SOUTHERN MANITOBA TONIGHT. THE SURFACE
AND H700 LOW ARE FORECAST TO TRACK NORTHEASTWARD ACROSS NORTH DAKOTA
TODAY...REACHING THE ND/MN/MANITOBA BORDER BY MIDNIGHT TUESDAY
NIGHT. STRONG FRONTOGENETIC FORCING WITH VERTICAL MOTION IN THE
DENDRITIC GROWTH ZONE ARE EXPECTED ALONG THIS TRACK. THE MODELS
INDICATE A DEEPER DENDRITIC GROWTH ZONE LATE THIS MORNING/AFTERNOON
IN NORTH CENTRAL NORTH DAKOTA. FARTHER SOUTH THE TEMPERATURE
PROFILES ARE WARMER EARLY ON THIS MORNING WHEN THE BEST VERTICAL
MOTION IS FORECAST. SO THE LATEST RUN OF THE MODELS VALIDATE THE
ONGOING FORECAST OF MORE PRECIPITATION/SNOWFALL NORTH CENTRAL VERSUS
ACROSS THE SOUTH. THE WARM AIR LAYER OFF THE SURFACE ASSOCIATED WITH
THE LOW LEVEL JET WILL BRING A CHANCE OF MIXED PRECIPITATION TO
PARTS OF SOUTHERN NORTH DAKOTA TODAY...AND THIS WILL LIMIT THE
AMOUNT OF SNOW EXPECTED IN THE SOUTHERN TIER OF COUNTIES.

THE LATEST SHORT TERM HIGH RESOLUTION MODELS ARE NOT AS ROBUST WITH
PRECIP OUTPUT AS THE GLOBAL MODELS...AND USED A BLEND OF HIGH RES
AND GLOBAL MODEL SNOW RATIO METHODS. SNOW IS EXPECTED TO BEGIN OVER
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AROUND 6 AM CST...AND
INCREASE QUICKLY BY AROUND 9 AM CST. THE GREATEST FORCING MOVES INTO
NORTHERN NORTH DAKOTA AROUND/AFTER 9 AM CST AND THE AFTERNOON HOURS
SHOULD SEE THE MOST SNOW ACCUMULATIONS ACROSS THE NORTH. THE
SOUTHWEST AND SOUTH CENTRAL SHOULD SEE UP TO AN INCH OR 2 OF SNOW BY
TONIGHT...WITH THE GREATEST SNOWFALL OF 3 TO OVER 5 INCHES OF SNOW
IN THE NORTH CENTRAL...WITH THE HIGHER AMOUNTS IN THE TURTLE
MOUNTAINS AREA.

WILL ADD BOTTINEAU COUNTY TO THE ONGOING WINTER WEATHER
ADVISORY...WHICH WILL INCLUDE WESTHOPE AND BOTTINEAU...VELVA AND
TOWNER...AND POINTS EAST TO RUGBY AND THE TURTLE MOUNTAINS. THERE
MAY BE A COUPLE LOCALES THAT REACH 6 INCHES OR A BIT MORE...BUT IN
GENERAL 3 TO 5.5 INCHES OF SNOW IS EXPECTED MOST AREAS IN THE
ADVISORY.

SNOW SHOULD TAPER TO LIGHT SNOW OR FLURRIES AS THE SYSTEM MOVES
NORTHEAST...BUT LINGER THROUGH THE NIGHT TUESDAY NIGHT AS A WEAK
TROWAL FEATURE KEEPS THE WRAP AROUND PRECIPITATION AS FAR WEST AS
MONTANA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM CST TUE DEC 22 2015

COOL AND GENERALLY QUIET WEATHER WILL PREVAIL IN THE LONG TERM.

FLURRIES OR LIGHT SNOW SHOWERS REMAIN POSSIBLE ON WEDNESDAY WITH
LINGERING CYCLONIC FLOW ACROSS THE REGION. ON THE LARGE SCALE...A
BROAD AND LOW-AMPLITUDE 500-MB TROUGH OVER THE WESTERN AND CENTRAL
UNITED STATES WILL BE REPLACED BY A MUCH DEEPER AND DYNAMICALLY-
ENERGIZED TROUGH CENTERED ON THE FOUR-CORNERS REGION BY SATURDAY.
THAT TRANSITION COULD YIELD LIGHT SNOW IN THE NORTHERN PLAINS LATE
ON CHRISTMAS DAY OR MORE SO ON FRIDAY NIGHT AS FLOW ALOFT BECOMES
SOUTHWESTERLY. HOWEVER...CONFIDENCE IN THE NORTHERN EXTENT OF ANY
LIGHT SNOW IS MODEST AT BEST AS SPLIT FLOW TAKES SHAPE ALOFT...AS
EXEMPLIFIED BY THE 00 UTC ECMWF...WHICH WAS A DRY SOLUTION ACROSS
MUCH OF WESTERN AND CENTRAL ND DURING THAT TIME FRAME.

TEMPERATURES WILL BE SEASONABLY COOL MOST OF THE PERIOD...AND WILL
BE COLDEST FRIDAY INTO SATURDAY...WHEN LOWS WILL BE AROUND 0 F AND
HIGHS WILL ONLY BE IN THE TEENS F PER A 00 UTC MULTI-MODEL BLEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 114 PM CST TUE DEC 22 2015

LIFR CONDITIONS IN HEAVY SNOW CONTINUING AT KMOT THROUGH THE
AFTERNOON...IFR CONDITIONS THEREAFTER IN SNOW THROUGH THE NIGHT.
IFR CONDITIONS EXPECTED AT KBIS THIS AFTERNOON IN LIGHT SNOW. IFR
IN LIGHT SNOW DEVELOPING AT KISN LATE THIS AFTERNOON THROUGH
TONIGHT. MVFR TO IFR CONDITIONS IN STRATUS AT KDIK AND KISN.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR NDZ004-005-012-
013.

WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ022-
023-025.

&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...CJS
AVIATION...AYD




AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 600 PM EST TUE DEC 22 2015

.SYNOPSIS...
A PARADE OF SYSTEMS IMPACTING THE FORECAST AREA THROUGH NEXT WEEK.
PERIODS OF HEAVY RAIN POSSIBLE.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
RADAR IMAGES SHOW LIGHT PCPN OR VIRGA ACROSS OUR AREA. EXPECT
THESE AREAS OF PCPN TO DISSIPATE LATER TONIGHT. ADJUSTED POPS TO
REFLECT THE LATEST RADAR AND MODEL TRENDS. REST OF FORECAST
REMAINS ON TRACK.

PREVIOUS DISCUSSION BELOW...
RAIN MOVING OUT OF THE AREA ALLOWING FOR A LITTLE SUN THIS
AFTERNOON ON THIS WARM FIRST DAY OF WINTER...BUT THE REPRIEVE FROM
PRECIPITATION WILL BE SHORT LIVED.

THE NEXT DISTURBANCE ARRIVES LATE TONIGHT INTO WED. MODELS
ENVELOPE OUR FORECAST AREA IN PRECIP...BUT MOST AGREE TO BRING THE
MOST PREVALENT QPF INTO THE AREA BETWEEN 100 AND 700 AM WEDNESDAY
MORNING. SCATTERED SHOWERS MAY LINGER THROUGH MUCH OF THE DAY
BEFORE ANOTHER WAVE ARRIVES WED NIGHT. THIS WAVE MAY PRODUCE A
THUNDERSTORM OR TWO ESPECIALLY IN THE OHIO RIVER VALLEY.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
MESSY FORECAST...WITH RELATIVELY HIGH UNCERTAINTY DUE TO MODEL
DIFFERENCES. SYNOPTICALLY...A DEEPENING SURFACE LOW WILL BE MOVING
NE THROUGH THE WESTERN GREAT LAKES WEDNESDAY NIGHT...AND WELL
NORTHWARD INTO CANADA THURSDAY. ALREADY MODEL DIFFERENCES HERE WITH
THE ECMWF AND GFS STRONGER AND SLOWER WITH THIS THAN THE NAM. THIS
WILL PUSH A COLD FRONT INTO THE MIDDLE OHIO RIVER VALLEY. MODELS
AGAIN LEND MORE UNCERTAINTY AS THE NAM AND ECMWF MOSTLY WASH THE
FRONT OUT IN THE OHIO RIVER VALLEY...WHILE THE GFS IS FASTER AND
PUSHES THE FRONT THROUGH BEFORE WASHING OUT ACROSS THE CENTRAL
APPALACHIANS. LOOKING AT THE FLOW ALOFT LENDS SOME ADDITIONAL INFO
TO THE EQUATION AS IT IS NEARLY PARALLEL TO THE FRONT. SO DO NOT
EXPECT MUCH PUSH TO THE FRONT. WITH THIS IN MIND...TRIED TO REFLECT
THE FRONT WASHING OUT OVER CWA WITH POPS DROPPING INTO CHANCE RANGE
THURSDAY NIGHT...AND THEN LIKELY POPS COMING BACK IN FROM THE SW AS
A WAVE REORGANIZES THE BOUNDARY AND STARTS PUSHING IT BACK NORTH AS
A WARM FRONT ON FRIDAY.

NAM SHOWING UP CLOSE TO 1000J/KG CAPE THURSDAY...WHILE LIKELY TOO
HIGH...IS IMPRESSIVE FOR LATE DECEMBER. SO HAVE CONTINUED THUNDER
WORDING. BEST SHEAR REMAINS NORTH AND WEST WHICH MAY LIMIT SEVERE
POTENTIAL FOR OUR CWA. HAVE ALSO ADDED MENTION IN HWO FOR POTENTIAL
HEAVY RAIN STARTING FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE UNSETTLED WX PATTERN ROLLS ON. THE OLD FRONTAL BOUNDARY WILL
BE RE ENERGIZED BY FRIDAY NIGHT AS INFLUX OF GULF MOISTURE
ADVECTS IN ON THE W PERIPHERAL OF THE UPPER RIDGE...AIDED BY
VARIOUS UPPER AIR IMPULSES. THIS PLACES PORTIONS OF THE CWA IN THE
ZONE FOR SOME MODERATE TO PERHAPS LOCALIZED HEAVY RAINFALL. THIS
AXIS OF HEAVY RAIN WILL GRADUALLY SHIFT N SATURDAY AS THE WARM
FRONT LIFTS N. ATTM IT APPEARS SE OH MAY SEE THE HIGHEST QPF
AMOUNTS...ON THE ORDER OF 1 TO LOLLIPOP 2 INCH AMOUNTS AMOUNTS
AROUND AN INCH ARE POSSIBLE ELSEWHERE. WE HAVE INSERTED A MENTION
OF POTENTIAL WATER PROBLEMS IN THE HWO PRODUCT HIGHLIGHTING SE OH
ZONES.

ONCE THE WARM FRONT LIFTS N OUT OF THE AREA ON SATURDAY...TEMPS
SHOULD RISE ACCORDINGLY. DEPENDING ON CLOUD COVER AND TIMING OF
EXODUS OF WARM FRONT...MUCH OF THE CWA MAY EXPERIENCE RECORD
BREAKING HIGH TEMPERATURES. BOTH THE MOS GUIDANCE FROM GFS/ECWMF
SUGGESTS MID TO UPPER 70S FOR PORTIONS OF THE
LOWLANDS...PARTICULARLY ALONG AND S OF I64 CORRIDOR. NOT GOING TO
BITE ON THAT JUST YET GIVEN UNCERTAINTY WITH EXTENT OF CLOUDS.
HOWEVER...DID RAISE MAXT INTO THE 72 TO 75F RANGE. SHOULD MORE SUN
BE REALIZED THEN THOSE UPPER 70S WOULD CERTAINLY BE REACHABLE.

STATUS QUO SATURDAY NIGHT AS THE UPPER RIDGE FLEXES ITS MUSCLE
INTO THE REGION AND A SIGNIFICANT PIECE OF ENERGY DROPS DOWN INTO
THE S PLAINS. HOWEVER THE OLD FRONTAL BOUNDARY WONT BE TOO FAR OFF
TO THE NW. OVERNIGHT LOWS WILL CONTINUE TO RUN WELL ABOVE NORMAL
JUST AS THE DAYTIME HIGHS DO.

SUNDAY WILL FEATURE THE UPPER TROF AXIS TO THE N TRY TO BEAT DOWN
THE RIDGE A BIT TO ALLOW THE FRONT TO SLIP BACK S INTO THE AREA.
HOWEVER...WITH SURFACE CYCLOGENESIS OVER TX AND MOST OF THE
DYNAMICS FOCUSED OVER THAT REGION...NOT EXPECTING WIDESPREAD
RAINFALL. AS SUCH...LOOK FOR HIGHS TO COME DOWN A BIT BUT STILL 20
TO 25 DEGREES ABOVE NORMAL.

UPPER LEVEL HEIGHTS BUILD ONCE AGAIN ON MONDAY AHEAD OF
AFOREMENTIONED SYSTEM TRACKING INTO THE UPPER MS VALLEY. WILL KEEP
POPS LOW UNTIL MONDAY NIGHT WHEN THE ASSOCIATED COLD FRONT
APPROACHES.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH EARLY WEDNESDAY. SATELLITE
IMAGES AND SFC OBS INDICATE PLENTY OF HIGH LEVEL CLOUDS OVER THE
AREA TONIGHT. LOW STRATUS COULD DEVELOP OVER AREAS THAT RECEIVED
RAIN. HOWEVER...NOT EXPECTING DENSE FOG FORMATION AS THE
BOUNDARY LAYER WINDS WILL BE 15 TO 20 KNOTS ACCORDING TO THE NAM
AND RAP MODELS. THE LOWER ATMOSPHERE SHOULD DECOUPLE TONIGHT
PRODUCING LIGHT AND VARIABLE WINDS OR CALM WINDS THROUGH THE EARLY
MORNING HOURS.

ANOTHER UPPER AIR DISTURBANCE BRINGS ANOTHER ROUND OF RAIN FOR
LATE TONIGHT INTO WEDNESDAY WHERE SOME IFR IS POSSIBLE
PARTICULARLY IN THE MTNS.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FLIGHT CATEGORIES MAY BE LOWER IN RAIN THAN
FORECAST.

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       22   23   00   01   02   03   04   05   06   07   08   09
EST 1HRLY       17   18   19   20   21   22   23   00   01   02   03   04
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    M    M    M    M    M    M    M
BKW CONSISTENCY  M    M    M    M    H    H    H    M    M    M    M    L
EKN CONSISTENCY  M    H    H    H    H    H    H    H    H    H    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z THURSDAY...

IFR CONDITIONS ARE LIKELY WEDNESDAY NIGHT THROUGH THURSDAY WITH
LOW CEILINGS AND RAIN.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...MZ/30/JW
NEAR TERM...ARJ/JW
SHORT TERM...MZ
LONG TERM...30
AVIATION...ARJ




AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 1211 PM CST TUE DEC 22 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM CST TUE DEC 22 2015

THE AREA CONTINUES TO BE SOCKED IN WITH LOW CLOUDS AND FOG VERY
EARLY THIS MORNING. THE MAIN CHALLENGE TODAY WILL BE HOW QUICKLY THE
FOG MIXES OUT AND HOW LONG LOWER CLOUDS WILL LINGER ACROSS THE AREA.
A DEEPENING AREA OF LOW PRESSURE PRESENTLY SITUATED OVER THE
NORTHERN ROCKIES IS EXPECTED TO SLIDE INTO WESTERN SOUTH DAKOTA BY
MID MORNING...THEN TRACK INTO EASTERN NORTH DAKOTA BY THIS EVENING.
OUT AHEAD OF THIS SYSTEM...SOUTHERLY WINDS WILL INCREASE ACROSS OUR
AREA THROUGH THE DAY AS THE GRADIENT TIGHTENS...AND WITH THAT EXPECT
TO SEE IMPROVING VISIBILITIES THROUGH THE MORNING INTO EARLY
AFTERNOON. THE RAP SEEMS TO BE HANDLING THE CURRENT BOUNDARY LAYER
MOISTURE THE BEST...AND WOULD INDICATE THAT LOW CLOUDS WILL ERODE
FROM THE SOUTHWEST DURING THE LATER MORNING AND AFTERNOON AS
SOUTH/SOUTHWEST MIXED LAYER WINDS INCREASE.  EVEN SO...WILL PROBABLY
REMAIN MOSTLY CLOUDY AS MID AND HIGH CLOUDS INCREASE ACROSS THE
REGION. WITH THE STRONG SOUTHERLY FLOW TODAY...WILL SEE TEMPERATURES
RESPOND ACCORDINGLY...WITH HIGHS A GOOD 15 DEGREES WARMER THAN
YESTERDAY. THIS WILL PLAY OUT TO AFTERNOON TEMPERATURES IN THE UPPER
30S TO LOWER 40S.

FOR TONIGHT...A SHORTWAVE LIFTS FROM SOUTHEASTERN NEBRASKA INTO
IOWA/SOUTHEASTERN MINNESOTA OVERNIGHT ON A SOUTHWESTERLY UPPER LEVEL
FLOW. WHILE THE MAIN ENERGY WILL PASS TO THE EAST OF OUR
CWA...MODELS ARE IN DECENT AGREEMENT WITH POSSIBLY GRAZING PORTIONS
OF OUR NORTHWESTERN IOWA/SOUTHWESTERN MINNESOTA ZONES WITH LIGHT
PRECIPITATION LATER TONIGHT. ALL MODELS ARE INDICATING PLUS 0 C 850
MB TEMPERATURES OVER THAT AREA DURING THAT TIME FRAME...SO
PRECIPITATION TYPE COMES DOWN TO SURFACE TEMPERATURES. PRESENTLY AM
FORECASTING SURFACE TEMPERATURES SLOWLY FALLING INTO THE LOWER 30S
VERY LATE TONIGHT...SO IF PRECIPITATION DEVELOPS CANNOT RULE OUT A
PERIOD OF FREEZING RAIN OVER THAT AREA. IT WILL BE A CLOSE CALL WITH
SURFACE TEMPERATURES JUST HOVERING AROUND THE FREEZING MARK...AND
WITH ONLY LIGHT QPF AM NOT EXPECTING ANY SIGNIFICANT IMPACTS AT THIS
POINT...BUT WILL BE SOMETHING TO KEEP AN EYE ON. IT WILL BE COOLER
BACK TO THE WEST HOWEVER AS A COLD FRONT BEGINS TO SLIDE INTO OUR
WESTERN CWA TOWARD MORNING...WITH LOWS RUNNING FROM NEAR 20 FROM
SOUTH CENTRAL SD THROUGH EAST CENTRAL SD...TO LOWER 30S THROUGH
NORTHWEST IA AS REFERRED TO ABOVE.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 416 AM CST TUE DEC 22 2015

AN UPPER LEVEL TROUGH LIFTS THROUGH NORTH DAKOTA WEDNESDAY
MORNING WHILE A OVER IOWA. MOISTURE DOES SURGE A LITTLE NORTHWARD IN
THE MORNING AHEAD OF AN ADVANCING COLD FRONT. MODELS A BIT MORE
AGGRESSIVE IN BRINGING SOME LIGHT POPS ACROSS OUR FAR SOUTHEAST
CORNER WHERE MOISTURE APPEARS TO BE DEEPER. DID BUMP UP POPS
SLIGHTLY AND EXPANDED THEM SLIGHTLY WEST OF PREVIOUS FORECASTS GIVEN
THE MORE WESTWARD MODEL TRENDS. PRECIPITATION TYPE IS LESS
CERTAIN...WITH FAIRLY WARM MID AND LOW LEVEL TEMPERATURES...WHILE
COLD AIR BEGINS TO SPREAD EAST AT THE SURFACE. THINK THAT MODELS MAY
BE A TOUCH TOO COLD AT THE SURFACE WHERE THE PRECIPITATION IS
EXPECTED...WITH READINGS RIGHT AROUND FREEZING. EXPECT TYPE TO BE
MAINLY LIGHT RAIN OR POSSIBLY VERY BRIEF FREEZING RAIN NEAR DAYBREAK
IF SURFACE TEMPERATURES COOL ENOUGH. THE PRECIPITATION SHOULD EXIT
THE FORECAST AREA TO THE EAST BY MID-AFTERNOON...AND WITH
TEMPERATURES WARMING BACK ABOVE FREEZING...ANY SLIPPERY SURFACES
FROM -FZRA WILL IMPROVE QUICKLY. WINDS WILL TURN BREEZY FROM THE
NORTHWEST WITH DECENT MIXING BEHIND THE FRONT DURING THE DAY...WHICH
WILL RESULT IN HIGHS IN THE UPPER 20S TO UPPER 30S.

ZONAL FLOW ON THURSDAY WILL SPELL A DRY AND SEASONALLY MILD DAY
ACROSS THE REGION. LIGHT WESTERLY WINDS WEDNESDAY NIGHT WILL TURN
SOUTHWESTERLY ON THURSDAY...AND HELP SCOUR OUT THE PERSISTENT CLOUD
COVERAGE FROM WEST TO EAST AS THE DAY PROGRESSES. TEMPERATURES WILL
BE SIMILAR TO WEDNESDAY WITH HIGHS IN THE UPPER 20S TO UPPER 30S.

CONFIDENCE IS INCREASING WITH THE POTENTIAL FOR SOME LIGHT
PRECIPITATION DEVELOPING FRIDAY INTO SATURDAY. WHILE THERE ARE
SOME TIMING CONCERNS BETWEEN THE MODELS...THEY ARE ALL HINTING AT
A GOOD POTENTIAL FOR SOME STEADY LIGHT TO MODERATE PRECIPITATION
DURING THIS PERIOD. THE GEM IS THE QUICKEST WITH LIFTING A WAVE
NORTHEAST FROM THE CENTRAL ROCKIES INTO THE MID MISSOURI VALLEY AS
EARLY AS LATE FRIDAY MORNING. THE ECMWF LAGS BY NEAR 12
HOURS...WHILE THE GFS IS BETWEEN THE TWO SOLUTIONS. ALL MODELS
BRING A DECENT AMOUNT OF QPF THROUGH THE CWA...HIGHEST WEST OF THE
JAMES RIVER AND NORTH OF I90 - OVER A HALF INCH -OVERNIGHT FRIDAY.
IN THIS AREA...TEMPS WILL BE COLD ENOUGH PRIMARILY FOR
SNOWFALL...WHILE AREAS SOUTH AND EAST MAY SEE MORE OF A MIX. STILL
A LOT OF UNCERTAINTY TO IRON OUT IN FUTURE RUNS...BUT IT WILL BE
SOMETHING TO WATCH CLOSELY.

LESS CONFIDENCE LIES BEYOND SATURDAY...AS THE FOCUS BECOMES THE
PROGRESSION OF A SLOW MOVING UPPER LEVEL LOW WOBBLING TOWARDS THE
RIO GRANDE AREA OF TEXAS ON SUNDAY. ACCORDING TO THE GFS...THIS
LARGE SYSTEM WILL LIFT NORTH NORTHEAST...BECOMING CENTERED OVER THE
KANSAS CITY AREA MONDAY MORNING THEN RAPIDLY HEADS INTO CENTRAL
WISCONSIN MONDAY EVENING. THIS PROGRESSION SEEMS TOO MUCH TOO
BULLISH. THE ECMWF MEANWHILE DOES NOT REACH THE KC AREA UNTIL
TUESDAY MORNING. SUFFICE TO SAY...CONFIDENCE IS LOW...SO JUST RAN
WITH THE ALL BLEND POPS FOR NOW. BOTH SOLUTIONS HOWEVER DO INDICATE
A PRETTY BIG IMPACT FOR OUR AREA WITH THIS STORM SYSTEM.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1210 PM CST TUE DEC 22 2015

STRONG SOUTHERLY FLOW WILL CONTINUE TO ADVECT THE IFR/LIFR/VLIFR
CONDITIONS NORTH AND EASTWARD THROUGH THE REMAINDER OF SW MN AND
NW IA THROUGH EARLY AFTERNOON. HAS ALREADY CLEARED KHON/KFSD/KSUX
BY 18Z. SURFACE WINDS WILL GUST IN EXCESS OF 25 KNOTS THROUGH THE
AFTERNOON. AS WINDS DIMINISH TONIGHT...EXPECT AT LEAST DEVELOPMENT
OF SOME MVFR CONDITIONS FOR KFSD AND KSUX...MAINLY IN TERMS OF
VISIBILITY FOR KFSD...AND PERHAPS A PERIOD OF IFR CEILINGS FOR
KSUX AFTER 04Z.

&&

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

$$

SHORT TERM...JM
LONG TERM...
AVIATION...CHAPMAN




AREA FORECAST DISCUSSION

NWS AUSTIN/SAN ANTONIO TX

 1151 AM CST TUE DEC 22 2015

.UPDATE...18Z AVIATION UPDATE BELOW.

&&

.AVIATION...FOG AND LOW CLOUDS HAVE DISSIPATED. VFR CONDITIONS
WILL PREVAIL THROUGH THE AFTERNOON. MVFR TO IFR CEILINGS CURRENTLY
FORECAST TO RE-DEVELOP THIS EVENING 02Z-06Z ALONG AND EAST OF THE
I-35/I-37 CORRIDORS...INCLUDING AUS/SAT. NAM12 AND HRRR SLIGHTLY
FASTER WITH THIS HAPPENING THEN CURRENT TAFS REFLECT. MAY NEED TO
ADJUST TIMING UP SLIGHTLY OF IFR DEVELOPMENT IN FUTURE TAF CYCLE.
LIFR CEILINGS AND VISIBILITIES A POSSIBILITY IN THIS SAME AREA
06Z-12Z...AHEAD OF A COLD FRONT. THE FRONT SHOULD MOVE THROUGH
THE I-35 CORRIDOR 12Z-15Z WED WITH VFR CONDITIONS DEVELOPING AT
AUS/SAT AND A DRY W TO NW WIND. DRT IS EXPECTED TO REMAIN VFR
OVERNIGHT.

&&

.PREV DISCUSSION... /ISSUED 958 AM CST TUE DEC 22 2015/

UPDATE...
BASED ON SATELLITE AND SURFACE OBSERVATIONAL TRENDS WILL EXTEND
THE DENSE FOG ADVISORY FOR ANOTHER HOUR UNTIL 11 AM CST. THERE ARE
NO OTHER CHANGES.

PREV DISCUSSION... /ISSUED 859 AM CST TUE DEC 22 2015/

UPDATE...
THE FOG HAS DISSIPATED ALONG THE HIGHWAY 90 CORRIDOR FROM EAST OF
DEL RIO TO SAN ANTONIO. HAVE CANCELLED THE DENSE FOG ADVISORY FOR
THIS AREA. THE DENSE FOG ADVISORY CONTINUES FOR AREAS FURTHER TO
THE SOUTH AND SOUTHEAST AS AREAS OF DENSE FOG REMAIN. MAY HAVE TO
EXTEND SOME COUNTIES PAST 10 AM AND WILL MONITOR THE DISSIPATION
OF THE FOG IN THESE AREAS. WHERE MENTIONED...HAVE REMOVED SHOWERS
FOR LATE THIS MORNING AS MOISTURE ADVECTION NOT ANTICIPATED UNTIL
MIDDAY AND THUNDER FOR THIS AFTERNOON AS A WARM/DRY SOUTHWESTERLY
MID LEVEL FLOW WILL KEEP THE AIRMASS CAPPED. HAVE REESTABLISHED
TEMPERATURE/DEW POINT/WIND TRENDS FOR THE REMAINDER OF TODAY BASED
ON OBSERVATIONAL TRENDS. OTHERWISE...SOUTH CENTRAL TEXAS FORECAST
IS ON TRACK.

PREV DISCUSSION... /ISSUED 409 AM CST TUE DEC 22 2015/

SHORT TERM (TODAY THROUGH WEDNESDAY)...

MAIN HIGHLIGHTS FOR THE SHORT TERM ARE THE ONGOING DENSE FOG THIS
MORNING AND INCREASING RAIN SHOWER CHANCES LATE TONIGHT INTO
WEDNESDAY MORNING. TEMPERATURES WILL REMAIN ABOVE NORMAL AS
MOISTURE POOLS AHEAD OF A WEAK FRONT THAT WILL MOVE THROUGH
TOMORROW MORNING.

LOW LEVEL AND SURFACE SATURATION IS OCCURRING OVER THE COASTAL
PLAINS INTO THE NORTHERN I-37 CORRIDOR AND IN AREAS JUST SOUTH OF
THE EDWARDS PLATEAU. A DENSE FOG ADVISORY IS IN EFFECT UNTIL 10AM
FOR THESE AREAS. LATEST HRRR/RAP GUIDANCE SUGGESTS THE SATURATION
MAY LINGER INTO THE LATE MORNING HOURS AND WILL NEED TO MONITOR IF
THE DENSE FOG ADVISORY NEEDS TO BE EXTENDED AN ADDITIONAL HOUR IN
THAT PARTICULAR LOCATION. LOW CLOUDS WILL REMAIN OVER THE REGION
THROUGH THE DAY AS LIGHT RAIN SHOWERS/DRIZZLE DEVELOP THROUGH THE
AFTERNOON ACROSS THE COASTAL PLAINS. MOISTURE INFLUX WILL OCCUR
THROUGH THE AFTERNOON FROM THE SOUTH AS A SHORTWAVE TROUGH SHIFTS
OVER NORTH TEXAS AIDING IN LIFT. STRONGEST LIFT WILL OCCUR LATE
TONIGHT INTO WEDNESDAY MORNING WITH MOST RAIN SHOWER ACTIVITY
NORTH AND EAST OF THE REGION. WHILE SOME THUNDERSTORMS COULD BE
POSSIBLE GIVE THE AMOUNT OF INSTABILITY...THE IMPLIED OMEGA VALUES
SUGGEST LIFT MAY NOT BE ENOUGH TO HAVE LARGE SCALE THUNDER
DEVELOPMENT WITH A MAJORITY BEING LIGHT TO MODERATE STREAMING RAIN
SHOWERS. THE FRONT WILL CLEAR THROUGH THE REGION NEAR NOON
WEDNESDAY AND SHOWER BRING THE RAIN CHANCES TO A CLOSE WITH
SLIGHTLY DRIER MOVING.

LONG TERM (THURSDAY THROUGH MONDAY)...

AN ACTIVE WEATHER PATTERN IS EXPECTED DURING THE END OF THE
HOLIDAY WEEK INTO THE WEEKEND WITH MULTIPLE RAIN CHANCES AND A
POTENTIAL MORE POTENT FRONTAL SYSTEM AND STORMS LATE SATURDAY OR
EARLY SUNDAY. WHILE THE ACTIVE PATTERN IS WELL AGREED UPON...THE
DETAILS WILL NEED TO CLOSELY WATCHED NEXT WEEKEND GIVEN THE POTENT
SET-UP BEING ADVERTISED ACROSS MULTI-MODEL SOLUTIONS.

CHRISTMAS EVE WILL BE A TRANSITION DAY AS MOISTURE BEGINS TO
STREAM BACK INTO THE REGION FROM THE SOUTH WITH SOUTHWEST H5 FLOW
OVER THE REGION. LOW END RAIN CHANCES WILL BE LIKELY FOR THE
COASTAL PLAINS AS THE LOW-LEVEL SATURATION OCCURS BUT NO LARGE
SCALE MODERATE SHOWERS ARE EXPECTED AT THIS TIME.

FOR CHRISTMAS DAY...MOISTURE TRANSPORT CONTINUES FROM THE SOUTH
AS STRONG LEE-SIDE CYCLOGENESIS COMMENCES IN COLORADO UNDER THE
STRONG INFLUENCE OF DEEPENING LONGWAVE TROUGH OVER THE LOWER WRN
CONUS. NO EMBEDDED SHORTWAVES SEEM TO EJECT AT THIS STAGE OVER THE
REGION WITH ONLY LIGHT SHOWER ACTIVITY OVER THE COASTAL PLAINS AND
MOSTLY CLOUDY CONDITIONS IN PLACE. TEMPERATURES WILL BE WELL ABOVE
AVERAGE WITH HIGHS LIKELY IN THE MID TO UPPER 70S EVEN DESPITE THE
CLOUDS.

GOING INTO THE HOLIDAY WEEKEND...RAIN SHOWERS AND THUNDERSTORMS
CHANCES WILL INCREASE MID AND UPPER LEVEL WIND SPEEDS INCREASE IN
CONCERT WITH THE VIGOROUSLY DEVELOPING H5 TROUGH. THE MAIN WINDOW
OF CONCERN WILL BE LATE SATURDAY INTO EARLY SUNDAY MORNING WHEN
THE BEST FORCING AND POSSIBLE FRONTAL INFLUENCE MOVE OVER THE
REGION. WHILE A MAJORITY OF THE GLOBAL MODELS SHOW THIS OVERALL
PATTERN...THE PLACEMENT OF THE FRONT AND HOW PROGRESSIVE THE
CLOSED LOW BECOMES WILL ULTIMATELY EFFECT THE EVOLUTION OF ANY
POTENTIAL HEAVY RAIN OR STRONG TO SEVERE THUNDERSTORM EVENT. IT
REMAINS TO UNCLEAR AT THIS STAGE WHAT THE EVOLUTION MAY BE AND
WILL NEED MORE RUNS FOR INCREASED CONFIDENCE. HOWEVER...THE
HOLIDAY WEEKEND WILL NEED TO MONITORED FOR POSSIBLE IMPACT
HAZARDOUS WEATHER. MODELS DO HIGHLIGHT A MAJORITY OF THE HEAVY
RAIN NORTH OF THE REGION WHERE FRONTAL CONVERGENCE WILL BE
STRONGER. THE CURRENT ADVERTISED GFS SOLUTION WOULD POINT TO A
POSSIBLE STRONG TO SEVERE SQUALL LINE. BUT AS JUST STATED
BEFORE...MORE RUNS WILL NEED TO BE MONITORED FOR HIGHER
PROBABILITY IN THIS POSSIBILITY. THE DRYLINE AND FRONT SHOULD PUSH
THROUGH THE REGION BY LATE SUNDAY WITH MONDAY BEING DRIER AND
SLIGHTLY COOLER.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              76  62  78  53  75 /  10  20  10   0  10
AUSTIN BERGSTROM INTL AIRPORT  76  62  79  48  76 /  10  20  10   0  10
NEW BRAUNFELS MUNI AIRPORT     78  61  81  51  77 /  10  20  10   0  10
BURNET MUNI AIRPORT            74  57  76  49  71 /  -   20  -    0  -
DEL RIO INTL AIRPORT           76  51  79  48  75 /   0  -    0   0  -
GEORGETOWN MUNI AIRPORT        75  61  76  48  73 /  10  20  10   0  10
HONDO MUNI AIRPORT             77  57  79  48  77 /  -   10  -    0  -
SAN MARCOS MUNI AIRPORT        76  62  79  51  76 /  10  20  10   0  10
LA GRANGE - FAYETTE REGIONAL   77  65  79  54  77 /  10  20  20  -   10
SAN ANTONIO INTL AIRPORT       77  62  80  53  77 /  10  10  -    0  10
STINSON MUNI AIRPORT           78  63  81  52  78 /  10  10  -    0  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...TREADWAY




AREA FORECAST DISCUSSION

NWS CHEYENNE WY

 256 PM MST TUE DEC 22 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 214 PM MST TUE DEC 22 2015

PRIMARY FORECAST CONCERN FOR THE SHORT TERM IS THE POTENTIAL FOR
SNOWFALL ACROSS THE EXTREME SE WYOMING PLAINS EXTENDING INTO THE
SOUTHERN NEBRASKA PANHANDLE THIS EVENING AND TONIGHT. EVERYTHING
ELSE APPEARS ON TRACK...WITH CURRENT KCYS RADAR LOOP SHOWING
SNOWFALL CONTINUING OVER THE MOUNTAINS. SNOTEL OBSERVATIONS ACROSS
THE SIERRA MADRE RANGE SHOW SOME IMPRESSIVE 36 HOUR SNOW
TOTALS...WITH TWO LOCATIONS NEAR BATTLE MOUNTAIN PASS ESTIMATING
BETWEEN 34 TO 42 INCHES OF SNOW SINCE LATE SUNDAY NIGHT. MORE SNOW
IS EXPECTED TONIGHT AND WEDNESDAY...SO THESE TOTALS WILL LIKELY GO
OVER 4 FEET IN A FEW LOCATIONS. MUCH LESS SNOW WAS OBSERVED OVER
THE SNOWY RANGE WITH ONLY ONE LOCATION ABOVE ONE FOOT OF TOTAL
ACCUMULATION. WILL CONTINUE THE WINTER WEATHER ADVISORIES FOR A
FEW OF THE LOWER ELEVATIONS OF CARBON COUNTY INTO THIS EVENING
WITH SOME ADDITIONAL SNOW AND BLOWING SNOW ALONG AND SOUTH OF I80.

ATTENTION THEN SHIFTS EASTWARD TOWARDS LARAMIE...THE CHEYENNE
AREA...AND ACROSS THE SOUTHERN NE PANHANDLE ALONG I80. MODELS ARE
IN PRETTY GOOD AGREEMENT SHOWING AN AREA OF RAPID FRONTOGENESIS
THIS EVENING JUST SOUTH OF THE COLORADO BORDER. MODELS SHOW A
WEAK WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT THIS
EVENING...WHICH IS CURRENTLY NEAR DENVER AND STRETCHES EASTWARD
OVER THE PLAINS NEAR I-70 OVER EASTERN COLORADO. THIS FEATURE
APPEARS TO BE FAST MOVING BUT POTENT...WITH EVEN THE HRRR AND NAM
SHOWING SOME MODERATE SNOW FROM THE I80 SUMMIT EASTWARD INTO
THE SOUTHERN NE PANHANDLE. TYPICALLY...GOOD MODEL AGREEMENT WOULD
INCREASE OVERALL CONFIDENCE 6 TO 12 HOURS OUT...BUT THE ISSUE IS
NO MODELS WAS SHOWING THIS FEATURE YESTERDAY. FOR NOW...INCREASED
POP TO 50 PERCENT ALONG THE I80 CORRIDOR INTO SIDNEY NEBRASKA.
WORDED FORECAST FOR OCCASIONAL SNOW AND 1 TO 2 INCHES OF SNOW
ACCUMULATION FOR NOW EVEN THOUGH THE NAM AND GEM ARE A BIT HIGHER.
WITH WESTERLY FLOW JUST OFF THE SURFACE AND RELATIVELY LOW
DEWPOINTS...CONCERNED THERE IS TOO MUCH DRY AIR TO PRODUCE MUCH
SNOWFALL. THE FRONT WILL QUICKLY PUSH SOUTH AND EAST LATE TONIGHT.

ANOTHER ROUND OF SNOW IS POSSIBLE FOR WEDNESDAY...ALTHOUGH MODELS
ARE NOT AS AGGRESSIVE AS THEY WERE YESTERDAY. ANOTHER QUICK MOVING
SHORTWAVE MOVES ACROSS WYOMING DURING THE AFTERNOON AND EVENING
HOURS...WITH SOME LIGHT SNOW ACROSS THE MOUNTAINS AND POTENTIALACROSS
THE EASTERN PLAINS. WINDS WILL ALSO BEGIN TO INCREASE AGAIN LATE
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE NEAR THE SURFACE
BUILDS ON THE WINDWARD SIDE OF THE ROCKY MOUNTAINS. MAY NEED HIGH
WIND HEADLINES FOR THE WIND PRONE AREAS ONCE AGAIN BY EARLY
THURSDAY MORNING WITH GUSTS AROUND 55 TO 60 MPH.
OTHERWISE...BECOMING COLDER EACH DAY WITH HIGHS ON IN THE 20S TO
LOW 30S BY CHRISTMAS EVE.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM MST TUE DEC 22 2015

NEXT UPPER SYSTEM TO AFFECT THE AREA WILL BE DIGGING OVER THE
WESTERN CONUS THURSDAY NIGHT WITH SW FLOW ALOFT OVER THE CWA. SOME
SNOW SHOWERS SHOULD OCCUR OVER THE HIGHER MTNS THURSDAY NIGHT AS
MOISTURE INCREASES IN THE FLOW OVER THAT AREA. ONE BATCH OF ENERGY
EJECTS NORTHEAST ACROSS THE CWA CHRISTMAS DAY WITH LEE
CYCLOGENESIS OVER SE COLORADO. THIS SHOULD BRING AN AREA OF LIGHT
SNOW TO MUCH OF THE CWA IN THE AFTERNOON AND EVENING BODING FOR A
WHITE CHRISTMAS FOR AT LEAST PARTS OF THE CWA FOR THE 4TH TIME IN
THE LAST 5 YEARS. MEANWHILE THE MAIN ENERGY WITH THE UPPER SYSTEM
STILL PROGGED TO CUT OFF OVER ARIZONA FRIDAY NIGHT WHILE THE SNOW
ENDS OVER OUR CWA. MODELS IN PRETTY GOOD AGREEMENT IN TRACKING THE
UPPER LOW ACROSS THE SOUTHERN ROCKYS INTO THE SOUTHERN PLAINS
SATURDAY THROUGH SUNDAY WITH THE GFS A BIT FASTER. THIS KEEPS THE
CWA DRY BUT COLD COMPLIMENTS OF A COLD SFC HIGH THAT WILL SETTLE
OVER THE NORTHERN PLAINS. THE UPPER LOW THEN LIFTS NORTHEAST ON
MONDAY AND MAY BRING A GLANCING SHOT OF WRAP-AROUND LIGHT SNOW TO
THE PANHANDLE. OTHERWISE WARMING SOME MONDAY AS SFC DOWNSLOPE FLOW
SETS UP BEFORE ANOTHER UPPER SHORTWAVE PASSES BY MONDAY NIGHT
BRINGING SOME COOLER AIR AGAIN AS WELL AS SOME MTN SNOW SHOWERS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 245 PM MST TUE DEC 22 2015

MAINLY VFR OVER ALL TERMINALS INTO EARLY THIS EVENING THEN SOME
MVFR/IFR CONDITIONS EXPECTED FOR A TIME TONIGHT ALONG A LINE FROM
KRWL TO KSNY AS A BAND OF LIGHT SNOW MAY DEVELOP. CONDITIONS
IMPROVING LATER TONIGHT IN THAT AREA. VFR AGAIN AREAWIDE
WEDNESDAY.

&&

.FIRE WEATHER...
ISSUED AT 214 PM MST TUE DEC 22 2015

NO FIRE WEATHER CONCERNS IN THE NEAR FUTURE WITH AFTERNOON
HUMIDITY VALUES WELL OUTSIDE OF CRITICAL THRESHOLDS IN ADDITION TO
SEVERAL CHANCES FOR PRECIPITATION OVER THE NEXT SEVERAL DAYS.
HEAVY MOUNTAIN SNOW IS ALREADY OCCURRING IN THE SNOWY/SIERRA
MADRES...AND IS LIKELY TO CONTINUE THROUGH THU.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...WINTER STORM WARNING UNTIL 5 PM MST WEDNESDAY FOR WYZ112-114.

     WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR WYZ111.

     WINTER WEATHER ADVISORY UNTIL 7 PM MST THIS EVENING FOR WYZ110.

NE...NONE.
&&

$$

SHORT TERM...TJT
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...TJT