Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/18/13

AREA FORECAST DISCUSSION

NWS ALBANY NY

113 AM EST SAT FEB 16 2013

.SYNOPSIS...
TONIGHT THROUGH SATURDAY NIGHT...WAVES OF LOW PRESSURE WILL MOVE
FROM THE MID ATLANTIC COAST TO WELL SOUTH AND EAST OF LONG ISLAND
BRINGING A LIGHT SNOWFALL FROM THE MID HUDSON VALLEY INTO WESTERN
NEW ENGLAND. THE WAVES OF LOW PRESSURE WILL MERGE INTO A POWERFUL
STORM EAST OF THE GULF OF MAINE BRINGING BLUSTERY AND COLD
CONDITIONS FOR SUNDAY...BUT WITH THE BULK OF SNOWFALL OCCURRING
ACROSS COASTAL NEW ENGLAND.

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 PM EST...HAD TO MAKE SOME CHANGES NAMELY TO REFLECT THE
FACT THAT LIGHT SNOW DEVELOPED MORE QUICKLY THAN ORIGINALLY THOUGHT
OVER THE CAPITAL DISTRICT AND EVEN POINTS TO THE SOUTH. INCREASED
POPS TO HIGH LIKELY OR EVEN CATEGORICAL IN THESE AREAS SINCE INDEED
IT IS EITHER SNOW (OR RAINING SOUTH WHERE SURFACE TEMPERATURES WERE
TOO WARM TO SUPPORT SNOW YET). HOWEVER...WITH EVAPORATIVE COOLING WE
ARE CONFIDENT THAT THE RAIN WILL CHANGE TO SNOW IN THESE AREAS IN A
FEW HOURS.

OTHERWISE...JUST RE-TOOLED THE HOURLY GRIDS...ESPECIALLY
TEMPERATURES WHICH HAD DROPPED THE FASTEST THE SNOW WAS FALLING.
HOWEVER...OVERNIGHT LOWS STILL LOOK REASONABLE SO LEFT THEM ALONE.

THE LATEST RUC13 INDICATES AN AREA OF ENHANCED 850-700 MB
FRONTOGENETICAL FORCING ACROSS EASTERN PA EXTENDING INTO EASTERN
NYS...AND THIS AREA HAS EXPANDED NE. IT WILL THEN GRADUALLY SHIFT
EASTWARD A FEW HOURS AFTER MIDNIGHT.

FOR AREAS MAINLY S AND E OF ALBANY...THE PRECIPITATION AREA SHOULD
CONTINUE EXPANDING N AND E THROUGH AROUND 2 AM...BEFORE SHIFTING
SLOWLY EAST. BOUNDARY LAYER TEMPS REMAIN SOMEWHAT MILD...AND
SHOULD ALLOW FOR PRECIP TO BEGIN MAINLY AS LIGHT RAIN IN VALLEY
AREAS...WITH A RAIN/SNOW MIX ACROSS HIGHER ELEVATIONS.
HOWEVER...AFTER ABOUT 1-2 HOURS OF EVAPORATIONAL COOLING...EVEN
VALLEY AREAS SHOULD TRANSITION TO SNOW AROUND OR JUST AFTER
MIDNIGHT...WITH HIGHER ELEVATIONS CHANGING OVER MORE QUICKLY.
STILL EXPECT SNOWFALL TOTALS OF AROUND AN INCH FOR HUDSON VALLEY
LOCATIONS...WITH PERHAPS 1-3 INCHES FOR AREAS E OF THE HUDSON
RIVER INTO NW CT...AND EASTERN DUTCHESS CO. FURTHER N AND
W...STILL EXPECT MAINLY UNDER AN INCH...WITH PERHAPS 1-2 INCHES
ACROSS PORTIONS OF THE SOUTHERN BERKSHIRES. THE GREATER CAPITAL
DISTRICT AND POINTS TO THE NORTH WILL RECEIVE A COATING TO AN INCH
OF SNOWFALL.

AS FOR MIN TEMPS...GIVEN THE ABUNDANT CLOUD COVER OVERNIGHT...AND
THE FACT THAT CURRENT TEMPS ARE RUNNING A BIT WARMER THAN PREVIOUS
GUIDANCE SUGGESTED...HAVE RAISED MINS BY ABOUT 1-3 DEGREES IN MOST
AREAS...WITH MID/UPPER 20S EXPECTED WITHIN THE HUDSON RIVER VALLEY
FROM ALBANY SOUTH...AND TEENS TO LOWER/MID 20S ACROSS THE SOUTHERN
ADIRONDACKS. ELSEWHERE...EXPECT MAINLY LOWER/MID 20S.

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
ANOTHER WAVE OF LOW PRESSURE MERGES OFFSHORE NEW ENGLAND AND RAPID
STRENGTHENING OF THE SYSTEM SHOULD OCCUR AS AN UPPER CUT OFF LOW
INTERACTS WITH THE SYSTEM. CONSENSUS FROM GUIDANCE AND ENSEMBLES
SUGGESTS THE STORM TRACKS TOO FAR EAST TO REALLY IMPACT OUR
FORECAST AREA...WITH PERHAPS JUST SOME ADDITIONAL LIGHT
ACCUMULATION FOR WESTERN NEW ENGLAND SATURDAY NIGHT AND EARLY
SUNDAY MORNING. STILL THERE SHOULD BE ENOUGH CLOUD COVER AND LIGHT
WINDS TO KEEP HIGH TEMPERATURES A LITTLE BELOW NORMAL...IN THE
LOWER TO MID 30S...20S IN HIGHER TERRAIN.

AS THE STORM RAPIDLY STRENGTHENS AND TRACKS INTO SOUTHEASTERN
CANADA...THE MEAN UPPER TROUGH AXIS BUILDS EAST AND VERY COLD AIR
SPILLS EAST INTO OUR REGION. THE TIGHT PRESSURE GRADIENT AROUND
THE STRONG LOW PRESSURE SHOULD SUPPORT STRONG WINDS THROUGHOUT THE
NORTHEASTERN U.S. MAKING FOR A NOTICEABLY COLD DAY SUNDAY. THERE
COULD BE WIND CHILL ISSUES AND MAYBE BORDERING ON WIND ADVISORY
WIND SPEEDS IN SOME AREAS. HIGHS SUNDAY IN THE LOWER TO MID
20S...SOME UPPER 20S SOUTHERN AREAS AND TEENS IN HIGHER TERRAIN.

THE STORM IS PREDICTED TO BE SLOW TO EXIT...AND THE WINDS MAY
DIMINISH ONLY GRADUALLY SUNDAY NIGHT INTO MONDAY. AGAIN...THERE
MAY BE SOME WIND CHILL ISSUES IN SOME AREAS...ESPECIALLY
SUNDAY NIGHT. LOWS SUNDAY NIGHT IN THE SINGLE NUMBERS TO LOWER
TEENS...AROUND OR JUST BELOW ZERO IN COLDER AREAS. HIGHS MONDAY IN
THE UPPER 20S TO LOWER 30S...LOWER 20S IN HIGHER TERRAIN.

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT...A RIDGE OF HIGH PRESSURE WILL SLIDE EASTWARD ACROSS
THE REGION...WHICH SHOULD BRING GENERALLY DRY CONDITIONS...WITH
DECREASING WIND. SOME HIGH/MID LEVEL CLOUDS MAY INCREASE LATE AT
NIGHT IN ADVANCE OF A SYSTEM APPROACHING FROM THE SOUTHWEST. EXPECT
ANOTHER COLD NIGHT...WITH MINS FALLING INTO THE SINGLE DIGITS ACROSS
NORTHERN AREAS...AND TEENS ELSEWHERE.

TUE-TUE NT...MODELS CONTINUE PREVIOUS TRENDS OF A MORE
PROGRESSIVE...AND FURTHER NORTH TRACK OF A SYSTEM DURING THIS TIME
PERIOD. STRONG WARM ADVECTION IN ADVANCE OF THIS SYSTEM SHOULD STILL
BRING A PERIOD OF PRECIPITATION TO THE REGION...MOST LIKELY TUE
AFTERNOON AND NIGHT...ALTHOUGH IT COULD START AS EARLY AS TUE
MORNING. FORECAST SOUNDINGS INDICATE MUCH OF THE REGION SHOULD BE
COLD ENOUGH TO SUPPORT MAINLY SNOW...ALTHOUGH BOUNDARY LAYER
TEMPS...AND SOME WARMING WITHIN THE 925-850 LAYER COULD ALLOW FOR
SOME RAIN TO MIX IN...ESP FOR AREAS SOUTH OF INTERSTATE 90 TUE
AFTERNOON. WILL INDICATE CHC POPS FOR THIS TIME PERIOD...WITH MAINLY
SNOW FOR NORTHERN AREAS...AND A RAIN/SNOW MIX FOR CENTRAL AND
SOUTHERN AREAS DEVELOPING BY TUE AFTERNOON...WITH PRECIPITATION
CHANGING TO SNOW ALL AREAS FOR TUE NT. MODELS HAVE TRENDED TOWARD
LESS OVERALL QPF...WITH THE 12Z/GEM REMAINING THE WETTER OUTLIER
ALLOWING FOR MORE SECONDARY COASTAL DEVELOPMENT FOR TUE NT. ASSUMING
THE 12Z/GFS/GEFS AND ECMWF PROVE CORRECT...IT APPEARS THAT THIS
EVENT SHOULD MAINLY COMPRISE OF LIGHT TO PERHAPS MODERATE
PRECIPITATION AMTS.

WED-THU NT...AS THE REMNANT UPPER LEVEL TROUGH PASSES NORTH OF THE
REGION WED AND WED EVENING...THE DEEP CYCLONIC FLOW WITHIN COLD AIR
ADVECTION SHOULD PROMOTE SCATTERED SNOW SHOWERS ACROSS MUCH OF THE
REGION...WITH THE MORE PERSISTENT SNOW SHOWERS ACROSS TRADITIONALLY
FAVORED AREAS OF THE WESTERN ADIRONDACKS...MOHAWK VALLEY...AND
POSSIBLY ACROSS THE SOUTHERN GREENS AND NORTHERN BERKSHIRES. THE
SNOW SHOWERS SHOULD DIMINISH IN AREAL COVERAGE LATE WED INTO WED
NT...FOLLOWED BY FAIR AND COLD CONDITIONS FOR THU INTO THU NT WITH
BELOW NORMAL TEMPS. SO...FOR MAX TEMPS...EXPECT LOWER/MID 30S IN
VALLEYS WED...WITH MAINLY 20S ACROSS HIGHER ELEVATIONS...WITH MAX
TEMPS A FEW DEGREES COLDER FOR THU. FOR MINS...EXPECT MAINLY 20S
ACROSS VALLEY REGIONS AND ADJACENT WESTERN NEW ENGLAND FOR WED AM
GIVEN CLOUDS AND SOME WIND...THEN TEENS IN LOWER ELEVATIONS...AND
SINGLE DIGITS ACROSS HIGHER ELEVATIONS FOR THU AM AND THU NT/FRI AM.

FRI...PREVIOUS RUNS OF VARIOUS GLOBAL DETERMINISTIC MODELS AND
ENSEMBLES HAVE INDICATED ANOTHER POTENTIAL STORM SYSTEM APPROACHING
THE REGION SOMETIME LATE FRI INTO NEXT WEEKEND. SEVERAL 12Z/15
MODELS HAVE TRENDED WEAKER...AND FURTHER SOUTH WITH ANY POTENTIAL
SYSTEM...GIVEN STRENGTHENING UPPER LEVEL RIDGING/BLOCKING ACROSS
CENTRAL/EASTERN CANADA. STILL A GREAT DEAL OF UNCERTAINTY AT THIS
TIME RANGE...SO HAVE MAINTAINED CHC POPS FOR FRI...WITH THERMAL
PROFILES SUGGESTING ALL SNOW. EXPECT MAX TEMPS TO POTENTIALLY REACH
30-35 IN LOWER ELEVATIONS...AND 20S FOR HIGHER TERRAIN.

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL DISTURBANCE WILL PASS ACROSS SOUTHERN PORTIONS OF
THE REGION LATE TONIGHT. THIS DISTURBANCE WILL BRING WIDESPREAD
LIGHT SNOW TO KPOU/KPSF UNTIL SHORTLY BEFORE SUNRISE...AND THROUGH
07Z/08Z AT KALB. AT KGFL LITTLE OR NO SNOW IS EXPECTED. ANY IFR
CONDITIONS AT KALB WILL END BY AROUND 07Z...BUT NOT UNTIL AROUND 10Z
AT KPOU AND KPSF. AT KGFL CONDITIONS WILL GET NO LOWER THAN MVFR.
AFTER 12Z...EXPECT VFR CONDITIONS AT ALL THE TAF SIDES FOR THE REST
OF THE TAF PERIOD ENDING AT 06Z SUNDAY.

WINDS WILL BE NORTH TO NORTHWEST AT LESS THAN 8 KTS THROUGH EARLY
SATURDAY MORNING...THEN INCREASE TO 8 TO 10 KTS BY LATE MORNING WITH
SOME GUSTS TO 15 KTS POSSIBLE...ESPECIALLY AT KALB. THESE WINDS WILL
PERSIST THROUGH 06Z SUNDAY.

OUTLOOK...
LATE SAT NT-MON NT...VFR. NO SIG WX.
TUE...MVFR/IFR TUE WITH MIXED PCPN.
TUE NITE-WED...MAINLY VFR. CHC MVFR -SHSN.

.HYDROLOGY...
NO HYDROLOGY PROBLEMS ARE EXPECTED OVER THE NEXT FEW DAYS. SNOW
MELT WILL CONTINUE TO BE GRADUAL THROUGH SATURDAY WITH ABOVE
FREEZING TEMPERATURES DURING THE DAY...AND BELOW FREEZING AT
NIGHT. TEMPERATURES WILL BECOME COLDER FOR THE 2ND HALF OF THE
WEEKEND SLOWING...AND EVEN ENDING THE SNOWMELT.

THE PREDOMINANT PTYPE TODAY INTO THE MID WEEK WILL BE SNOW. THE
SYSTEMS DURING THAT TIME FRAME ARE EXPECTED TO ONLY PRODUCE LIGHT
SNOW AMOUNTS. THEREFORE...NO IMPACTS ARE EXPECTED ON THE ALY HSA
WATERWAYS.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

$$
SYNOPSIS...NAS
NEAR TERM...HWJIV/KL
SHORT TERM...NAS
LONG TERM...KL
AVIATION...GJM
HYDROLOGY...NAS

AREA FORECAST DISCUSSION

NWS ALBANY NY

1225 AM EST SAT FEB 16 2013

OTHERWISE...JUST RE-TOOLED THE HOURLY GRIDS...ESPECIALLY
TEMPERATURES WHICH HAD DROPPED THE FASTEST THE SNOW WAS FALLING.
HOWEVER...OVERNIGHT LOWS STILL LOOK REASONABLE SO LEFT THEM ALONE.

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL DISTURBANCE WILL PASS ACROSS SOUTHERN PORTIONS OF
THE REGION LATER TONIGHT. THIS DISTURBANCE WILL BRING WIDESPREAD
MID LEVEL CLOUDS OVERNIGHT...ALONG WITH A BRIEF PERIOD OF LIGHT
SNOW AT KPOU AND KPSF AFTER MIDNIGHT...WHICH COULD INITIALLY BE
MIXED WITH RAIN. KALB APPEARS TO BE ON THE NORTHWEST EDGE OF THE
DEVELOPING PRECIPITATION SHIELD...AND WILL ONLY INDICATE VCSH FOR
NOW UNLESS RADAR TRENDS INDICATE OTHERWISE LATER THIS EVENING.

IN AREAS WHERE THE SNOW DEVELOPS...A PERIOD OF MVFR OR POSSIBLE
IFR VSBYS AND CIGS WILL BE POSSIBLE BETWEEN 06Z-10Z/SAT.
ELSEWHERE...MAINLY VFR CONDITIONS ARE EXPECTED THROUGH DAYBREAK.

ON SATURDAY...AREAS OF MVFR CIGS COULD LINGER AT KPOU AND KPSF
THROUGH AROUND 15Z. OTHERWISE...VFR CONDITIONS ARE EXPECTED.

WINDS WILL BECOME MAINLY NORTHWEST OVERNIGHT AT GENERALLY LESS
THAN 7 T. WINDS WILL BECOME NORTH TO NORTHWEST ON SATURDAY AT
GENERALLY 5-10 KT...ALTHOUGH MAY BE A BIT STRONGER AT KALB AND
KPSF...ESP FROM LATE MORNING INTO THE AFTERNOON HOURS.

OUTLOOK...
SAT NT-TUE NT...VFR. NO SIG WX.
WED...VFR BCMG MVFR/IFR. -SN/-RA POSSIBLE IN AFTERNOON.

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

$$
SYNOPSIS...NAS
NEAR TERM...HWJIV/KL
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL
HYDROLOGY...NAS

AREA FORECAST DISCUSSION

NWS LINCOLN IL

1129 AM CST SAT FEB 16 2013

.DISCUSSION...
ISSUED 1001 AM CST SAT FEB 16 2013

DEEP UPPER LOW CENTERED OVER THE GREAT LAKES CONTINUES TO BE THE
PREDOMINANT WEATHER-MAKER ACROSS CENTRAL ILLINOIS TODAY. VERY COLD
AIR ALOFT ASSOCIATED WITH THIS FEATURE...WITH 12Z 500MB TEMP OF -40C
AT KILX. DESPITE PRESENCE OF SURFACE HIGH PRESSURE...STEEP LAPSE
RATES WILL LEAD TO THE DEVELOPMENT OF SCT-BKN CU ACROSS NORTH-CENTRAL
ILLINOIS THIS AFTERNOON. 13Z HRRR EVEN HINTS AT SOME CONVECTIVE
SNOW-SHOWERS ALONG/NORTH OF I-74 AFTER 20Z. LATEST VISIBLE SATELLITE
IMAGERY IS ALREADY SHOWING CU BEGINNING TO DEVELOP...AND UPSTREAM
OBS SHOW AN AREA OF LIGHT SNOW ACROSS NORTHEAST IOWA. HAVE UPDATED
THE FORECAST TO GO WITH SUNNY SKIES THIS MORNING...FOLLOWED BY
PARTLY SUNNY CONDITIONS IN THE AFTERNOON. HAVE ALSO MENTIONED
SCATTERED FLURRIES ALONG/NORTH OF I-74. ZONE UPDATE HAS ALREADY
BEEN ISSUED.

BARNES
&&

.AVIATION...
ISSUED 1129 AM CST SAT FEB 16 2013

MOSTLY CLEAR SKIES PREVAIL ACROSS CENTRAL ILLINOIS LATE THIS
MORNING...HOWEVER CU-FIELD IS RAPIDLY DEVELOPING ALONG AND NORTH
OF I-74. DUE TO VERY COLD AIR ALOFT AND RESULTING STEEP LAPSE
RATES...EXPECT CU TO BECOME SCT-BKN AT TIMES. HAVE THEREFORE
INCLUDED A TEMPO GROUP FOR LOW VFR CEILINGS AT THE I-74 TERMINALS
THIS AFTERNOON. FURTHER SOUTHWEST...MOSTLY CLEAR SKIES WILL
PERSIST AT BOTH KSPI AND KDEC. DIURNAL CLOUD COVER WILL DISSIPATE
BY SUNSET...FOLLOWED BY MOSTLY CLEAR SKIES OVERNIGHT. HIGH CLOUDS
CURRENTLY OVER THE PLAINS WILL PUSH EASTWARD SUNDAY MORNING...AS
WARM FRONT APPROACHES FROM THE WEST. WINDS WILL INITIALLY BE FROM
THE NORTHWEST AT AROUND 10KT THIS AFTERNOON...THEN WILL BECOME
LIGHT/VARIABLE TONIGHT AS HIGH PRESSURE DRIFTS ACROSS THE AREA.
ONCE THE HIGH MOVES FURTHER EAST...SOUTHEAST WINDS WILL DEVELOP ON
SUNDAY.

BARNES
&&

.PREV DISCUSSION...
ISSUED 330 AM CST SAT FEB 16 2013

FAIRLY QUIET WEATHER EXPECTED THIS WEEKEND AS BELOW NORMAL TEMPS
THROUGH TONIGHT...MODERATE BACK ABOVE NORMAL EARLY NEXT WEEK. MORE
ACTIVE WEATHER PATTERN EXPECTED DURING THE UPCOMING WORK WEEK WITH
TWO FAIRLY STRONG WEATHER SYSTEMS TO IMPACT THE REGION MON AND MON
NIGHT AND THU AND THU NIGHT. 00Z MODELS ARE IN GOOD AGREEMENT
THROUGH EARLY NEXT WEEK WITH 1ST WEATHER SYSTEM AND THEN DIVERGE
WITH HANDLING 2ND WEATHER SYSTEM LATER NEXT WORK WEEK AND WILL
STAY CLOSE TO HPC/NCEP GUIDANCE. MODELS OVERALL HAVE TRENDED A BIT
SLOWER WITH BOTH WX SYSTEMS AND STEERED THE FORECAST IN THAT
DIRECTION WITH LOWER POPS BOTH MONDAY MORNING AND THU MORNING
ESPECIALLY NE AREAS. STILL LOOKS LIKE MAINLY RAIN MONDAY AND
MONDAY NIGHT WHILE MORE SNOW OR A MIXTURE OF PRECIPITATION THU AND
THU NIGHT WITH ACCUMULATIONS POSSIBLE THEN.

SHORT TERM...TODAY THROUGH MONDAY NIGHT

STRONG UPPER LEVEL TROF REMAINS OVER EASTERN NORTH AMERICA EAST OF
THE ROCKIES TODAY AND WILL SHIFT EAST OF IL LATER TONIGHT AND SUNDAY.
AN EMBEDDED SHORT WAVE OVER NEBRASKA WILL TRACK SW OF IL TODAY
KEEPING THE BRUNT OF ITS CLOUDS SW OF CENTRAL IL TODAY. OVERALL A
PARTLY TO MOSTLY SUNNY DAY WITH MORE CLOUDS NE HALF. TEMPS ABOUT
10F BELOW NORMAL TODAY WITH UPPER 20S NE AND LOWER 30S SW. NW
WINDS 10 TO 15 MPH AND GUSTS UP TO 20 MPH AGAIN TODAY. MOSTLY
CLEAR SKIES TONIGHT AND LIGHTER WINDS AS HIGH PRESSURE RIDGE OVER
THE CENTRAL PLAINS MOVES INTO IL BY DAWN SUNDAY. COLD LOWS OF 15
TO 20F EXPECTED TONIGHT AND COLDEST NE AREAS. TEMPS MODERATE
SUNDAY AS HIGH PRESSURE RIDGE DRIFTS EAST ACROSS THE OH/TN VALLEYS
WITH RETURN SE FLOW INTO IL AND MOSTLY SUNNY SKIES. HIGHS IN THE
UPPER 30S NE AND LOWER 40S SW. BREEZY SOUTHERLY WINDS BY MONDAY
AND BUMPED UP HIGHS A FEW MORE DEGREES IN THE UPPER 40S AND LOWER
50S. STRONG LOW PRESSURE MOVES INTO THE UPPER MS VALLEY MONDAY AND
SWINGS COLD FRONT EAST THRU IL MONDAY NIGHT. THIS TO LIKELY
DEVELOP SHOWERS BY MONDAY AFTERNOON AND MON EVENING AND THEN
DIMINISH OVERNIGHT MONDAY NIGHT. BETWEEN A QUARTER AND HALF INCH
OF RAIN OVER CENTRAL IL AND LOCALLY HIGHER AMOUNTS IN SE IL WHERE
ISOLATED THUNDERSTORMS POSSIBLE SOUTH OF CHARLESTON/MATTOON MONDAY
AFTERNOON AND MON EVENING. HAVE CHANCE OF LIGHT SNOW OVERNIGHT
MONDAY NIGHT AS PRECIPITATION DIMINISHES BUT LITTLE OR NO
ACCUMULATIONS.

LONG TERM...TUESDAY THROUGH FRIDAY NIGHT

QUIET WEATHER RETURNS TUE AND WED ALONG WITH COLDER TEMPS AND
COLDEST ON WED AS CANADIAN HIGH PRESSURE RIDGES INTO IL WED. THEN
ANOTHER LOW PRESSURE EJECTS NE INTO THE MS VALLEY BY THU NIGHT
RETURNING MORE PRECIPITATION DEVELOPING DURING THE DAY THU FROM SW
TO NE AND CONTINUE THU NIGHT. APPEARS COLD ENOUGH FOR SNOW THU
MORNING THEN MIX OF FREEZING RAIN...SLEET AND RAIN TOO SOUTHERN
AREAS THU AFTERNOON. THIS TO TRANSITION BACK TO SNOW FROM NW TO SE
DURING THU NIGHT AS COLDER AIR RETURNS. COULD BE SOME SNOW
ACCUMULATIONS THU AND THU NIGHT ESPECIALLY NORTH OF I-70 WITH
HEAVIEST AMOUNTS NORTH OF I-72. MODELS STILL NOT IN BEST AGREEMENT
WITH TRACK OF STORM SYSTEM AND OVERALL MODELS HAVE TRENDED FURTHER
NORTH WITH TRACK OF SURFACE LOW NEAR CENTRAL IL LATER THU NIGHT.

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

AREA FORECAST DISCUSSION

NWS LINCOLN IL

1001 AM CST SAT FEB 16 2013

.DISCUSSION...
ISSUED 1001 AM CST SAT FEB 16 2013

BARNES
&&

.AVIATION...
ISSUED 506 AM CST SAT FEB 16 2013

LITTLE CHANGE NEEDED TO PREVIOUS TAF SET. HAVE BEEN SEEING A FEW
PATCHES OF CLOUDS AROUND 2500 FEET DRIFT SOUTHWARD OVER THE LAST
FEW HOURS...AND THESE WILL LINGER FOR ANOTHER HOUR OR TWO. STEADY
NORTHWEST WINDS AROUND 10 KNOTS TODAY WILL BECOME A BIT MORE
LIGHT AND VARIABLE THIS EVENING...AS AN AXIS OF HIGH PRESSURE
DRIFTS OVERHEAD.

GEELHART
&&

.PREV DISCUSSION...
ISSUED 330 AM CST SAT FEB 16 2013

SHORT TERM...TODAY THROUGH MONDAY NIGHT

LONG TERM...TUESDAY THROUGH FRIDAY NIGHT

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

AREA FORECAST DISCUSSION

NWS NORTHERN INDIANA

214 PM EST SAT FEB 16 2013

.AVIATION...
VARIABLE CONTS THIS AFTN WITHIN MOIST AND UNSTABLE BNDRY LYR AND
EVIDENT IN OBSVD CONDS IN HEAVY SNOW SHSN AND IN RECENT KFWA METAR. XPC
DIURNALLY ENHANCED ACTIVITY INLAND TO DECAY OUT BY LT AFTN W/LOSS OF
HEATING. HWVR INTENSIFYING SHORE PARALLEL SINGLE BAND W/LK SUP
CONNECTION SEEN TAKING SHAPE WEST OF MANISTEE DOWN TO LUNDINGTON AND
POISED TO MARCH SWD THIS EVENING. IMPACTS AT KSBN APPEAR TO BE BRIEF
AS BAND PIVOTS WWD TO WEST OF TERMINAL BUT GOING TO BE CLOSE.
REGARDLESS A PD OF LIFR CONDS IN HEAVY SHSN LIKELY FOR A TIME THIS
EVENING AND WILL AWAIT SWD EVOLUTION OF THIS BAND BFR ATTEMPTING TO
TIME IT IN TAF. OTRWS CONDS IMPRVG ON SUN W/RTN OF VFR CONDS.

.UPDATE...
WK BUT DISTINCT MESOLOW WHICH SPUN UP INVOF OF PARENT SFC TROUGH NR
KMKG ARND 0930Z CONTS TO CURL ESE THIS MORNING AND CURRENTLY WEST OF
KBTL. UPSTREAM CVRG BAND WHILE NOT AS INTENSE AS EARLIER XPCD TO
REINTENSIFY THROUGH LT MORNING ALG A KBIV...KAZO...KOEB LINE AS LK
AGGREGATE THERMAL TROUGHING STRENGTHENS AND UPSTREAM LK MSTR FLUX
MAXIMIZES INLAND. THIS MAY NECESSITATE A EWD EXPANSION OF CURRENT
ADVISORY OVR ST JOE MI TO INCLUDE BRANCH AND PERHAPS EVEN HILLSDALE.
TRENDING NR TERM RUC SOLUTIONS ADVERTISE A SIMILAR EVOLUTION AND
EVEN DIP FOCUSED BAND DOWN TO KTOL BY LT AFTN. HWVR GIVEN THINGS
STILL IN A STATE OF FLUX WILL CONT TO MONITOR DVLPMNTS AS PLACEMENT
ON LOCATION OF WRN FLANK STILL UNCERTAIN. OTRWS SIG UPSTREAM NEG
THETA-E ADVTN ASSOCD/W BLDG ARCTIC RIDGING LOOKS TO STIFLE ADDNL
SRN LAKE DVLPMNT UNTIL LT AFTN TIMED W/FURTHER AND MORE FVRBL LL
VEERING INTO SW MI/NW IN.

.SHORT TERM... /TODAY THROUGH SUNDAY NIGHT/

PRIMARY FOCUS REMAINS ON LAKE EFFECT SNOW AMOUNTS AND IMPACTS ACROSS
FAR NORTHERN INDIANA AND SOUTHWEST LOWER MICHIGAN TODAY THROUGH
SUNDAY MORNING...

A DIGGING UPPER TROUGH AXIS AND EMBEDDED SHORTWAVE ENERGY WILL PIVOT
THROUGH THE SOUTHERN GREAT LAKES REGION THIS MORNING WITH THE CORE
OF COLD AIR (7H TEMPS TO -28C) DROPPING THROUGH THIS AFTERNOON INTO
TONIGHT. THIS WILL RESULT IN EXTREME OVER-LAKE INSTABILITY WITH
IMPRESSIVE LAKE-7H TEMP DIFFERENTIALS NEAR 30C AND UVM/MOISTURE
MAXIMIZED WITHIN THE DGZ THROUGH THE EVENT. HOWEVER...MORE WESTERLY
300 DEGREE LOW LEVEL TRAJECTORIES AND A SUBSTANTIAL DIURNAL
COMPONENT TODAY WILL LIMIT ORGANIZATION (MORE CELLULAR) WITH DRY
UPPER MIDWEST ENTRAINMENT AND LARGE SCALE SUBSIDENCE BEHIND THIS
MORNING`S MID LEVEL WAVE ALSO LIMITING FACTORS FOR SIGNIFICANT SNOW
ACCUMS. THIS DRYING/POOR FETCH COMBO COULD EVEN RESULT IN A PERIOD
OF LITTLE/NO SNOW SHOWER ACTIVITY BY LATE MORNING/EARLY AFTERNOON.
THIS WILL LIKELY KEEP SNOW TOTALS IN CHECK THROUGH 00Z WITH
LOCATIONS NORTH OF HWY 6 IN INDIANA/MI STILL EXPECTING SNOW ACCUMS
BETWEEN 1 AND 4 INCHES. ELSEWHERE...EXPECT VERY COLD CONDITIONS WITH
ISOLATED TO SCATTERED SNOW SHOWERS POSSIBLE...ESPECIALLY EARLY THIS
MORNING ALONG THE SYNOPTIC TROUGH WITH DUSTING TO HALF INCH TYPE
ACCUMS POSSIBLE.

SLIGHT IN-CLOUD VEERING TO A MORE FAVORABLE 320-330 DEGREE
FETCH...LITTLE/NO SHEAR...AND FAVORABLE DIURNAL TIMING SHOULD
COMBINE TO ALLOW AN INTENSE SHORE PARALLEL SNOW BAND TO MATERIALIZE
WITHIN AN INTENSIFYING DIRECT THERMAL CIRCULATION/AGGREGATE SFC
TROUGH TONIGHT. HI-RES GUIDANCE CONTINUES TO SUGGEST MESOLOW
DEVELOPMENT WHICH WILL NO DOUBT DETERMINE WHERE THIS BAND SETS
UP/PIVOTS OVERNIGHT INTO EARLY SUNDAY MORNING. INTENSE SNOWFALL
RATES OF 2-3 INCHES PER HOUR WILL BE POSSIBLE WITHIN THIS BAND.
QUESTIONS OBVIOUSLY AT THIS JUNCTURE REMAIN EXACTLY WHERE THIS SETS
UP AND POSSIBLE INTERFERENCE (FLOW INTERRUPTION) FROM ANY MESOLOW. A
00Z MODEL CONSENSUS DOES FAVOR NORTHERN/EASTERN BERRIEN, WESTERN
CASS MI, AND ST JOE INDIANA AS THE PIVOT POINT WITH THE POTENTIAL
FOR SEVERAL HOURS OF HEAVY SNOW. FOR NOW WILL HOLD SERVE WITH
CURRENT HEADLINES GIVEN UNCERTAINTIES. REGARDLESS THERE IS THE
POTENTIAL FOR SIGNIFICANT LAKE EFFECT SNOW MAINLY LATER THIS EVENING
INTO THE OVERNIGHT HOURS. ELSEWHERE...MAINLY DRY AND COLD.

WAA WITH RIDGING ALOFT AND BACKING LOW LEVEL TRAJECTORIES WILL BRING
ANY LINGERING LAKE EFFECT SNOW TO AN END BY EARLY SUNDAY AFTERNOON
WITH NO SENSIBLE WX CONCERNS SUNDAY AFTERNOON/NIGHT.

.LONG TERM... /MONDAY THROUGH FRIDAY/
ALL IN ALL LITTLE SIG CHNG FM YDAY ANALYSIS WITH OVERALL INCRSD
CONFIDENCE WRT QPF/TIMING ASSOCD WITH LOW/MODERATE AMPLITUDE NRN
STREAM WAVE /CRNTLY APPROACHING PAC NW/ TO MAINTAIN PROGRESSIVE
NATURE INTO ERLY NEXT WEEK. SYSTEM TRAVERSING SCNTL CAN/NRN PLAINS
MONDAY TO SLOW TUESDAY/INCRSGLY VERTICALLY STACKED AS SRN END/SE CO
FNTL WAVE PROCEEDS INTO OCCLUSAL IN NRN GRTLKS. SOME
DISCOUNT/CAUTION TO THE MORE RAPID NAM/SREF SIGNALS...PER VARIANCE
AS NOTED IN PMDHMD. AT SAME TIME DIFFICULT TO UNDERESTIMATE
SHALLOW/DRY/COLD CP AIR ADVANCE AFFORDED BY POLEWARD CONNECTIVITY AT
SFC/LLVLS OF SUCH INTENSE NRN MANITOBA ANTICYCLONE. ATTEMPT TO
FURTHER DETAIL TIMING OF RAFL ONSET THROUGH CWA WITH SIGNALS OF DEEP
MSTR/UVM HOLDING OFF TIL LATE IN DAY ONCE LATE OPEN GOMEX FEED/NRN
TERMINUS OF HIGHLY INTENSE 925-8H LLJ TO 65 KTS AIMING FM MO
BOOTHILL THROUGH MOUTH OF OH RVR INTO FAR SWRN IN TO DEMAND FORCED
MOIST ASCENT...MOST LIKELY UNTIL LATE AFTN/21 UTC MON TIMEFRAME.
RAPID EWD SHIFT OF FEATURE INTO UPR OH VLY BY 06 UTC TO GRTLY LIMIT
UVM ACRS RGN AFT RAFL SLUG...WITH TRANSITION TO LIGHTER RA/SN MIX TO
SN THROUGH THE NIGHT WITH LITTLE/NO ACCUMS.

THEREAFTER...MINOR LES RESPONSE PER WRLY FLOW AND MUTED MIXED LYR
DEPTH. ALL EYES RMN ON LATE WEEK SYSTEM. SLIGHT NWD SHIFT SFC/ALOFT
NOTED PER MULTIMODEL CONSENSUS...THOUGH CERTAINLY NOT SIG ENOUGH TO
DISMISS. INTMTN/SWRN STATES TROF AT APEX 00 UTC THU/F120. THEREAFTER
HOLD DOUBTS AS TO EXACT TRACK. LOW AMPLITUDE/WEAKNESS NOTED IN
DOWNSTREAM RIDGE THEREAFTER AS SYSTEM EJECTS FM ERN NM INTO CNTL
PLAINS DY6. THIS DOWNSTREAM WEAKNESS COULD AFFORD POTNL TO BIFURCATE
AND MAINTAIN A MORE EWD MOMENTUM INTO DY7. ALSO TREND TWRDS CPC 8-14
ANALOGS COULD SUGGEST A POTNL REXING OF SYSTEM PER WEAK/ANTECEDENT
SRN CANADA/JAMES BAY RIDGE AIDED BY A POS HGHT ANOMOLY PHASE
THEREAFTER INTO DY8. POTNL STILL HOLDS OUT AS BEST SYNOPTIC SYSTEM
SINCE DEC 26 AS THU NIGHT ONSLAUGHT OF INITIAL STRONG ISENT
LIFT/STRONG EVAP/STRONGER DYNAMIC COOLING PROCESSES TO ELICIT RAPID
WETBULB COLLAPSE FOR SN/PSBLY BECMG HVY ACRS SWRN/WRN CWA BY ERLY
FRI. THEREAFTER A DOWNSTREAM RIDGE SPLIT/REX DVLPMNT REMOTELY COULD
OFFER A STALLED DEEP SYSTEM TO SLOWLY WITHER ON VINE ACRS NRN IN/SRN
LWR MI...AT LEAST THROUGH HERO FCSTR EYES. LARGE STANDARD DEVIATION
SPREAD PER MEDIUM RANGE MODEL ACCUMULATIONS. SAN COMPACTION WITH
CLIMATOLOGICAL MEAN NEAR 14/1 RATIOS USED AFFORDED RANGES GNRLY
WITHIN 3-7 INCH RANGE...FWIW AT F144-180.

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST /3 AM CST/ SUNDAY FOR
INZ003>005.

MI...LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST SUNDAY FOR MIZ079.

LAKE EFFECT SNOW WARNING UNTIL 10 AM EST SUNDAY FOR MIZ077-078.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR LMZ043-046.

SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...T
UPDATE...T

AREA FORECAST DISCUSSION

NWS NORTHERN INDIANA

836 AM EST SAT FEB 16 2013

.SHORT TERM... /TODAY THROUGH SUNDAY NIGHT/

PRIMARY FOCUS REMAINS ON LAKE EFFECT SNOW AMOUNTS AND IMPACTS ACROSS
FAR NORTHERN INDIANA AND SOUTHWEST LOWER MICHIGAN TODAY THROUGH
SUNDAY MORNING...

WAA WITH RIDGING ALOFT AND BACKING LOW LEVEL TRAJECTORIES WILL BRING
ANY LINGERING LAKE EFFECT SNOW TO AN END BY EARLY SUNDAY AFTERNOON
WITH NO SENSIBLE WX CONCERNS SUNDAY AFTERNOON/NIGHT.

.AVIATION... /06 UTC TAFS/

LAKE EFFECT SNOW SHOWERS WILL IMPACT SBN THROUGH THE
PERIOD...ESPECIALLY THIS MORNING AND AGAIN SATURDAY NIGHT. THIS
WILL RESULT IN VARIABLE FLIGHT CONDITIONS THROUGH THE PERIOD.
THERE COULD BE A LULL IN THE SNOW SHOWER ACTIVITY LATER THIS
MORNING INTO THE EARLY AFTERNOON AS SUBSIDENCE/DRYING BUILDS IN
BRIEFLY BEHIND THIS MORNING`S WEAK MID LEVEL SHORTWAVE. AN INTENSE
SINGLE BAND MAY SET UP OVER SBN SATURDAY NIGHT WITH LIFR CONDITIONS
AND INTENSE 1-3 INCH PER HOUR SNOWFALL RATES POSSIBLE. EXPECT
MAINLY DRY/VFR CONDITIONS AT FWA...ALTHOUGH CANNOT RULE OUT A FEW
SNOW SHOWERS THROUGH THE PERIOD WHICH COULD BRIEFLY REDUCE
VISBYS.

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST /3 AM CST/ SUNDAY FOR
INZ003>005.

MI...LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST SUNDAY FOR MIZ079.

LAKE EFFECT SNOW WARNING UNTIL 10 AM EST SUNDAY FOR MIZ077-078.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR LMZ043-046.

SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...STEINWEDEL
UPDATE...T

AREA FORECAST DISCUSSION

NWS GOODLAND KS

510 PM MST SUN FEB 17 2013

.UPDATE...
ISSUED AT 508 PM MST SUN FEB 17 2013

HAVE CANCELLED THE RED FLAG WARNING AS WINDS HAVE REMAINED WELL
BELOW THRESHOLDS.

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE RIDGE OVER
THE CWA...WITH SHORTWAVE TROUGH ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH OVER THE GREAT BASIN. AT THE SURFACE A STRONG COLD
FRONT EXTENDS FROM NORTH DAKOTA ACROSS EASTERN WYOMING AND SOUTH
ACROSS EASTERN UTAH. STRONG SUBSIDENCE IS ALREADY APPARENT ON WV
IMAGERY BEHIND THIS FRONT.

CLOUD COVER HAS REMAINED IN PLACE OVER THE CWA...WHICH HAS
RESTRICTED MIXING RESULTING IN WEAKER WINDS THAN ORIGINALLY
EXPECTED. RH VALUES HAVE DROPPED WELL BELOW RFW CRITERIA ACROSS THE
REGION...WITH SINGLE DIGIT RH VALUES AT MANY LOCATIONS. ONLY A FEW
LOCATIONS SO FAR HAVE REACHED WIND CRITERIA FOR WIND...WITH MANY
OTHER LOCATIONS BORDERLINE. I PLAN ON LEAVING THE RFW IN PLACE FOR
NOW...DUE TO HOW DRY WE ARE...AND THE POTENTIAL FOR WINDS TO
INCREASE BETWEEN NOW AND 00Z.

A STRONG COLD FRONT OVER THE NORTHERN PLAINS WILL DROP SOUTH OVER
THE CWA THIS EVENING AND OVERNIGHT. GFS/NAM BOTH INDICATE 40-50KT
WINDS BEHIND THIS FRONT OVER OUR CWA...WITH BL WINDS 20-30KT. STRONG
PRESSURE GRADIENT COMBINED WITH STRONG SUBSIDENCE SHOULD HELP BRING
WINDS TO THE SURFACE. WHILE THESE CONDITIONS MAY ONLY LAST AN HOUR
OR TWO AT THE MOST...I WAS CONFIDENT ENOUGH TO ISSUE WIND ADVISORY
FOR THE SUDDEN ONSET OF GUSTS TO 55 MPH AND THE POSSIBILITY OF
BLOWING DUST STARTING AT 03Z. ORIGINALLY I CONSIDERING EXTENDING
THIS ADVISORY THROUGH THE DAY TOMORROW. HOWEVER...PRESSURE GRADIENT
SHOULD BEGIN TO RELAX AS FRONT MOVES SOUTH AND EAST...AND DAYTIME
MIXING IS STILL IN QUESTION IF CLOUDS LINGER THROUGH THE DAY. I
HAVE CURRENT ADVISORY ENDING AT 12Z TO ALLOW NEXT SHIFTS TO
REEVALUATE FOR TOMORROW.

STRONG FORCING AND DECENT MID LEVEL MOISTURE WILL BE IN PLACE
OVERNIGHT WITH SHORTWAVE TROUGH PASSAGE...HOWEVER LOWER LEVELS
REMAIN VERY DRY. GFS/ECMWF ARE SHOWING LIGHT QPF IN THE WEST...WITH
GEM CREATING A BULLSEYE IN THE NORTHEAST. WHILE I COULDNT RULE OUT A
FEW FLURRIES OR SPRINKLES...I WAS NOT CONFIDENT ENOUGH THAT ANYTHING
WOULD REACH THE GROUND...SO I LEFT MENTION OUT.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

LONG TERM FOCUS REMAINS ON THE UPPER 4-CORNERS LOW EMERGING EAST
OF THE ROCKIES OVER THE HIGH PLAINS IN THE VICINITY OF NORTHEAST
NEW MEXICO/SOUTHEAST COLORADO/SOUTHWEST KANSAS EARLY THURSDAY
MORNING. MODELS HAVE REMAINED CONSISTENT WITH EACH OTHER AND HAVE
ONLY VARIED SLIGHTLY WITH LOW CENTER PLACEMENT FROM RUN TO RUN.
AM THEREFORE CONFIDENT WITH WIDESPREAD PRECIPITATION SHOWN ACROSS
THE ENTIRE FORECAST AREA AND AM CONFIDENT IN STAYING WITH THE
HIGHER POPS FOR THIS EVENT. TEMPERATURES ARE SOMEWHAT MORE
QUESTIONABLE AS THERE HAS BEEN SOME VARIATION IN TIMING AND EXTENT
OF THE COLD AIR MOVING INTO THE REGION ALONG WITH THE EVENTUAL
CHANGE OVER TO SNOW AND THE POSSIBILITY OF SOME INSTABILITY AND
THUNDER AS THIS EVENT INITIATES.

CONDITIONS WILL REMAIN DRY WITH HIGH TEMPERATURES ON TUESDAY
REMAINING SIMILAR TO MONDAY. OVERNIGHT LOWS WILL BE WARMER
TUESDAY NIGHT/EARLY WEDNESDAY AS CLOUDS BEGIN TO SPREAD EAST OF
THE ROCKIES AHEAD OF THE LOW PRESSURE SYSTEM AS IT MOVES INTO THE
INTERMOUNTAIN REGION. COOLER HIGH PRESSURE AT THE SURFACE WILL
CONTINUE TO SLIDE SOUTH INTO THE PLAINS STATES AND BACK INTO THE
FORECAST AREA FROM THE EAST WITH RETURN FLOW AROUND THE HIGH
BRINGING MORE MOISTURE INTO THE REGION. IT APPEARS A DRYLINE/WARM
FRONT FEATURE MOVES ACROSS THE CENTRAL HIGH PLAINS BY LATE
WEDNESDAY...BRINGING THE POTENTIAL FOR ISOLATED THUNDERSTORMS
ALONG WITH RAIN SHOWERS FOR THE WARMER AREAS WHILE SNOW IS
POSSIBLE MAINLY ACROSS THE NORTHEAST LATE. WEDNESDAY NIGHT/EARLY
THURSDAY THE LOW CENTER MOVES INTO SOUTHWEST KANSAS...WRAPPING
COLDER AIR AND MOISTURE AROUND THE SYSTEM WITH POSSIBLE HEAVY SNOW
ACROSS THE NORTHEAST PORTION OF THE FORECAST AREA DURING THAT
TIME. PRECIPITATION IS EXPECTED TO TAPER OFF DURING THE DAY ON
THURSDAY AND END BY THURSDAY EVENING. WINDS MAY BE GUSTY WITH THE
SYSTEM AND PRODUCE AREA OF BLOWING SNOW.

COLDEST TEMPERATURES OF THE WEEK WILL BE ON THURSDAY AND THURSDAY
NIGHT AS THE SYSTEM MOVES OUT WITH FRESH SNOW AND A POSSIBLE
DECREASE IN SKY COVER OVERNIGHT. CONDITIONS FRIDAY AND SATURDAY
WILL BE DRY WITH TEMPERATURES WARMING GRADUALLY WITH A BRIEF SHORT
WAVE RIDGE ALOFT ON SATURDAY AHEAD OF THE NEXT TROUGH SWINGING
THROUGH THE UPPER FLOW AND ACROSS THE ROCKIES LATE SUNDAY.

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 400 PM MST SUN FEB 17 2013

VFR CONDITIONS EXPECTED THROUGH THE PERIOD AT KGLD AND KMCK.
SOUTH TO SOUTHWEST WINDS AROUND 10KTS AT TAF ISSUANCE WILL SHIFT
TO THE NORTHWEST AT 25KTS WITH GUSTS TO 35KTS OR SO BETWEEN 03Z-
04Z AT BOTH TERMINALS AS A COLD FRONT MOVES THROUGH. THESE WINDS
WILL REMAIN IN THE 25G35KT RANGE THROUGH MUCH OF THE PERIOD WITH A
SLIGHT DECREASE AROUND 23Z MONDAY. CLOUDINESS WILL INITIALLY REMAIN
LIMITED TO CIRRUS LEVEL BUT WILL LOWER BEHIND THE FRONT.
HOWEVER...AT THIS TIME THE LOWER CLOUD HEIGHTS WILL NOT IMPACT
FLIGHT CATEGORIES SO WILL NOT DETAIL IN TAF FOR EITHER SITE.

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR KSZ001>004-
013>016-027>029-041-042.

CO...WIND ADVISORY UNTIL 5 AM MST MONDAY FOR COZ090>092.

NE...WIND ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR NEZ079>081.

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

AREA FORECAST DISCUSSION

NWS GOODLAND KS

400 PM MST SUN FEB 17 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 400 PM MST SUN FEB 17 2013

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 8 PM MST /9 PM CST/ THIS EVENING TO 5 AM MST
/6 AM CST/ MONDAY FOR KSZ001>004-013>016-027>029-041-042.

RED FLAG WARNING UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
KSZ002>004-013>016-027>029-041-042.

CO...WIND ADVISORY FROM 8 PM THIS EVENING TO 5 AM MST MONDAY FOR
COZ090>092.

RED FLAG WARNING UNTIL 6 PM MST THIS EVENING FOR COZ253-254.

NE...WIND ADVISORY FROM 8 PM MST /9 PM CST/ THIS EVENING TO 5 AM MST
/6 AM CST/ MONDAY FOR NEZ079>081.

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

AREA FORECAST DISCUSSION

NWS GOODLAND KS

350 PM MST SAT FEB 16 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 144 PM MST SAT FEB 16 2013

LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH ACROSS
WESTERN US WITH ITS AXIS CENTERED ALONG THE ROCKY MOUNTAINS...AND A
LARGE SCALE TROUGH ACROSS THE EASTERN US. A SHORTWAVE TROUGH
UPSTREAM OF THE H5 RIDGE IS DEEPENING OVER THE PACIFIC NW COAST.

THE H5 RIDGE IS EXPECTED TO SHIFT EAST WITH A VERY DRY AIRMASS
MOVING OVER OUR CWA. THE SHORTWAVE TROUGH UPSTREAM WILL DIG SOUTH
TOWARDS THE GREAT BASIN OVERNIGHT AND TOWARDS THE CENTRAL ROCKIES
MIDDAY. SURFACE GRADIENT WILL INCREASE AHEAD OF AN APPROACHING COLD
FRONT WITH WINDS INCREASING ACROSS THE SOUTHERN HALF OF THE CWA
THROUGH THE DAY. A PRE-FRONTAL TROUGH AXIS WILL MOVE INTO THE
NORTHERN HALF OF THE CWA DURING THE AFTERNOON HOURS SUNDAY WITH
WINDS DECREASING ALONG AND IMMEDIATELY BEHIND THIS FEATURE. WITH
STRONG WAA AND DEEP MIXING EXPECTED WE ARE LIKELY TO SEE NEAR RECORD
HIGH TEMPERATURES IN THE MID/UPPER 60S...POSSIBLY 70F.

VERY LOW TD VALUES ARE ALSO EXPECTED BY SUNDAY AFTERNOON...WITH RH
VALUES DROPPING TO RFW CRITERIA ACROSS MOST OF THE CWA DURING THE
AFTERNOON. WE COULD SEE SINGLE DIGIT RH VALUES IN THE SOUTH AND
WEST. AT THIS TIME...I AM MOST CONFIDENT IN WIND/RH CROSSOVER SOUTH
OF I-70 WHERE I HAVE ISSUED RED FLAG WARNING. WITH THE POSSIBILITY
OF WINDS DIMINISHING ACROSS THE NORTH...I AM NOT AS CONFIDENT IN
WIND/RH CROSSOVER...SO I ISSUED A FIRE WEATHER WATCH ACROSS THE
CENTRAL AND NORTHEASTERN PARTS OF THE CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 219 PM MST SAT FEB 16 2013

LONG TERM FOCUS IS ON THE LOW PRESSURE SYSTEM MOVING EAST OF THE
ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION WEDNESDAY NIGHT
THROUGH THURSDAY NEXT WEEK.

SUNDAY NIGHT A COLD FRONT MOVES THROUGH THE REGION WITH THE UPPER
TROUGH MOVING THROUGH THE CENTRAL ROCKIES TO MOVE ACROSS THE
CENTRAL HIGH PLAINS BY MID DAY ON MONDAY. SINCE CONDITIONS WILL BE
MOSTLY DRY...EXPECT ONLY AN INCREASE IN CLOUDS AND COOLER
TEMPERATURES WITHOUT ANY PRECIPITATION. HIGH TEMPERATURES WILL BE
ABOUT 20 DEGREES COOLER ON MONDAY THAN THEY WERE ON SUNDAY. GUSTY
NORTHWEST WINDS ARE ALSO EXPECTED DURING THE DAY BEHIND THE FRONT.

SHORT WAVE RIDGING ALOFT IS EXPECTED ON TUESDAY AND TUESDAY NIGHT
IN THE WAKE OF THE EXITING TROUGH AND PRIOR TO THE NEXT
APPROACHING LOW PRESSURE CENTER DIVING SOUTH ALONG THE WEST COAST
THAT MOVES INTO THE FAR SOUTHWEST UNITED STATES BY WEDNESDAY
MORNING. A COOL HIGH PRESSURE AREA REMAINS OVER THE NORTHERN
PLAINS AND EXTENDS INTO THE CENTRAL PLAINS THROUGH
WEDNESDAY...TRANSPORTING LOW LEVEL MOISTURE INTO THE SOUTHERN AND
CENTRAL HIGH PLAINS REGIONS WITH THE POSSIBILITY OF A LITTLE
INSTABILITY MOVING OVER THE FORECAST AREA TO PRODUCE A MIX OF RAIN
AND SNOW SHOWERS AND POSSIBLY EVEN A RUMBLE OF THUNDER LATE IN THE
DAY ON WEDNESDAY IN THE WARM SECTOR AHEAD OF THE MAIN UPPER LOW
CENTER AS IT MOVES EAST OF THE ROCKIES IN THE VICINITY OF
SOUTHEAST COLORADO. HAVE LEFT THE MENTION OF THUNDER OUT FOR NOW.
RAIN TRANSITIONS TO SNOW OVERNIGHT WEDNESDAY NIGHT AND EARLY
THURSDAY MORNING AS COLDER AIR IS BROUGHT FURTHER SOUTH ACROSS THE
HIGH PLAINS. DEPENDING UPON THE TIMING OF THE CHANGE OVER TO SNOW
AND THE AMOUNT OF MOISTURE AND INSTABILITY THAT ACTUALLY AFFECTS
THE FORECAST AREA...THERE IS THE POTENTIAL FOR A SIGNIFICANT
SNOWFALL ACROSS THE CENTRAL HIGH PLAINS REGION MAINLY ACROSS THE
NORTHEAST HALF OF THE FORECAST AREA. IT`S STILL FAR ENOUGH OUT
THAT CONFIDENCE IS A LITTLE LACKING...BUT MODEL SOLUTIONS HAVE
BEEN ADVERTISING REASONABLY SIMILAR SOLUTIONS THROUGH THE LATTER
PORTIONS OF NEXT WEEK.

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 350 PM MST SAT FEB 16 2013

VFR THROUGH THE PERIOD AT KGLD AND KMCK. W/SW WINDS UNDER 10KTS AT
THE START OF THE PERIOD WILL REMAIN SO THROUGH 17Z OR SO BEFORE
INCREASING AND BECOMING GUSTY FROM THE SOUTHWEST BY 19Z AND
CONTINUING THROUGH 23Z OR SO. PEAK GUSTS DURING THE AFTERNOON AT
KGLD AROUND 26KTS WITH 20KTS OR SO AT KMCK. LITTLE TO NO
CLOUDINESS THROUGH MUCH OF THE PERIOD WITH ONLY AN INCREASE IN
CIRRUS FROM THE NORTHWEST BY MID TO LATE AFTERNOON.

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 11 AM MST /NOON CST/ TO 6 PM MST /7 PM
CST/ SUNDAY FOR KSZ027>029-041-042.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ003-004-013>016.

CO...RED FLAG WARNING FROM 11 AM TO 6 PM MST SUNDAY FOR COZ254.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ253.

NE...NONE.
&&

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

AREA FORECAST DISCUSSION

NWS GOODLAND KS

242 PM MST SAT FEB 16 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 144 PM MST SAT FEB 16 2013

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 219 PM MST SAT FEB 16 2013

LONG TERM FOCUS IS ON THE LOW PRESSURE SYSTEM MOVING EAST OF THE
ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION WEDNESDAY NIGHT
THROUGH THURSDAY NEXT WEEK.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1031 AM MST SAT FEB 16 2013

VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW MID TO HIGH LEVEL CLOUDS /AROUND 10KFT AGL/ WILL DEVELOP THIS
AFTERNOON BUT OTHERWISE SKIES WILL BE CLEAR THROUGH THE FORECAST
PERIOD. BREEZY NORTHWEST WINDS THIS AFTERNOON /20KTS GUSTING TO
NEAR 30KTS/ WILL DECREASE THIS EVENING...BECOMING LIGHT AND
VARIABLE THOUGH GENERALLY OUT OF THE WEST. EARLY TOMORROW WINDS
WILL BE LIGHT OUT OF THE SOUTHWEST AS A SURFACE THROUGH SETS UP
NEAR THE KANSAS- COLORADO BORDER.

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 11 AM MST /NOON CST/ TO 6 PM MST /7 PM
CST/ SUNDAY FOR KSZ027>029-041-042.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ003-004-013>016.

CO...RED FLAG WARNING FROM 11 AM TO 6 PM MST SUNDAY FOR COZ254.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ253.

NE...NONE.
&&

SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JJM

AREA FORECAST DISCUSSION

NWS GOODLAND KS

145 PM MST SAT FEB 16 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 144 PM MST SAT FEB 16 2013

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 241 AM MST SAT FEB 16 2013

SUNDAY NIGHT-MONDAY NIGHT...LARGE SCALE FORCING FOR ASCENT WILL
INCREASE SHARPLY OVERNIGHT SUNDAY AS STRONG FRONTAL CIRCULATION
EXPECTED BEHIND THE SFC FRONT AND COINCIDES WELL WITH STRONGEST DIV
Q AND PV ADVECTION ACROSS MUCH OF THE CWA. THETA E LAPSE RATES DO
INDICATE CONDITIONAL INSTABILITY WILL BE PRESENT AT THIS TIME...BUT
GIVEN T-TD DEPRESSIONS OF AIR MASS IN ADVANCE OF THIS SYSTEM MAKE ME
DOUBTFUL THAT WIDESPREAD SATURATION WILL DEVELOP TO TAKE ADVANTAGE
OF POTENTIAL INSTABILITY. WILL KEEP POPS IN THE 5-10 PERCENT RANGE
UNTIL MORE CONFIDENT ABOUT POTENTIAL SATURATION IN THE H7-H5 LAYER
SUNDAY NIGHT AND MONDAY MORNING. PERIOD OF SUBSIDENCE WILL DEVELOP
BEHIND THIS SYSTEM AND WHILE THERE WILL BE A PERIOD OF STRONG
FRONTOGENESIS LINGERING ACROSS THE AREA...DO NOT THINK FORCED ASCENT
WILL BE STRONG ENOUGH TO PRODUCE ANY MEANINGFUL PRECIPITATION.

TUESDAY THROUGH FRIDAY...AN UPPER LEVEL RIDGE WILL START OUT THE
PERIOD ON TUESDAY WITH A BACKDOOR COLD FRONT MOVING IN DURING THE
NIGHT.

WEDNESDAY AN UPPER LEVEL LONG WAVE TROUGH WILL APPROACH THE
TRI-STATE AREA. DURING THE DAY THE 850-700MB LAYER SATURATES AND
STRONG ISENTROPIC LIFT DEVELOPS OVER THE AREA AHEAD OF THE LONG WAVE
TROUGH. WITH TEMPERATURES BELOW FREEZING FOR MUCH OF THE
AREA...FREEZING DRIZZLE MAY DEVELOP. WILL ONLY MENTION A RAIN/SNOW
MIX AT THIS TIME RANGE INSTEAD.

WEDNESDAY NIGHT COOLER AIR MOVES IN AS THE UPPER LEVEL TROUGH MOVES
CLOSER TO THE AREA CAUSING THE PRECIPITATION TO CHANGE TO SNOW BY
THE OVERNIGHT HOURS. DURING THE OVERNIGHT HOURS THE UPPER LEVEL
TROUGH AND SURFACE LOW MOVE OVER THE AREA...CAUSING THE LIFT TO
PEAK. WILL LIKELY SEE THE MOST SNOWFALL OCCUR LATE WEDNESDAY NIGHT
THROUGH EARLY THURSDAY MORNING AS THE SURFACE LOW AND UPPER LEVEL
TROUGH MOVE ACROSS THE AREA.

THURSDAY MORNING A STRONG COLD FRONT MOVES IN BEHIND THE SURFACE LOW
AS IT MOVES EAST. BEHIND THE FRONT NORTHWEST WINDS WILL QUICKLY
STRENGTHEN. MEANWHILE SNOWFALL WILL TAPER OFF FROM WEST TO EAST AS
THE WINTER STORM SYSTEM MOVES OUT OF THE AREA...COMING TO AN END BY
THE OVERNIGHT HOURS. CURRENTLY LOOKS LIKE THE WINDS WILL STRENGTHEN AS
THE SNOWFALL BEGINS TO WIND DOWN WHICH WILL HELP REDUCE THE IMPACTS
OF THE STORM.

FRIDAY LOOKS DRY AS A SHORT WAVE RIDGE MOVES OVER THE AREA AHEAD OF
THE NEXT UPPER LEVEL TROUGH MOVING ACROSS THE DESERT SOUTHWEST.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1031 AM MST SAT FEB 16 2013

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 11 AM MST /NOON CST/ TO 6 PM MST /7 PM
CST/ SUNDAY FOR KSZ027>029-041-042.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ003-004-013>016.

CO...RED FLAG WARNING FROM 11 AM TO 6 PM MST SUNDAY FOR COZ254.

FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ253.

NE...NONE.
&&

SHORT TERM...DR
LONG TERM...JRM/JTL
AVIATION...JJM

AREA FORECAST DISCUSSION

NWS TOPEKA KS

1135 PM CST FRI FEB 15 2013

...UPDATE TO AVIATION...

.DISCUSSION...
12Z UPPER AIR DATA DEPICTED AT 130KT JET DIVING SOUTH OUT OF WESTERN
SASKATCHEWAN WITH WIDESPREAD 500MB TEMPS OF AROUND -40C OVER THE
NORTHERN PLAINS AND EASTERN CANADA. AN UPPER LEVEL TROF WAS MAKING
SOUTHWARD PROGRESS OUT OF THE WESTERN DAKOTAS IN RECENT HOURS PER
WATER VAPOR IMAGERY. WEAK RADAR RETURNS HAVE DEVELOPED OVER MUCH OF
NORTHERN KANSAS THOUGH DEWPOINT DEPRESSIONS AROUND 20F ARE LIKELY
KEEP MUCH OF THIS WEAK ACTIVITY FROM REACHING THE GROUND. 20Z
SURFACE-3KM LAPSE RATES NEAR 9C/KM WERE NOTED IN CENTRAL
NEBRASKA...WITH AROUND 8C/KM VALUES EAST AND ALSO SOUTHEAST INTO THE
LOCAL AREA.

THE MAIN ISSUES TONIGHT ARE WHERE AND HOW LONG THE SNOW SHOWERS WILL
LAST. THE VARIOUS GUIDANCE ALL POINTS TO A MORE SUSTAINED AREA OF
PRECIPITATION SOMEWHERE IN NORTHEAST KANSAS...WITH THE DETAILS THE
MAIN ISSUE. AS THE UPPER TROF CONTINUES SOUTH TO SOUTHEAST...THE
LAPSE RATES REMAIN NEAR 8C/KM WELL INTO THE NIGHT AS FRONTOGENESIS
AROUND 750MB INCREASES AND FOCUSES ON THE NORTHEAST TIP OF A
DEVELOPING THETA-E RIDGE AT THIS LEVEL...RESULTING IN GOOD LIFT
THROUGH THE DENDRITIC GROWTH ZONE. THE MOST RECENT HRRR AND RAP DATA
HAS BEEN PUSHING THIS AREA NORTHEAST...FAVORING FAR NORTHEAST KANSAS
MAINLY AROUND 03Z. HAVE INCREASED CHANCES AND AMOUNTS UP HERE...BUT
STILL LIMITED MOISTURE AND THE COVERAGE OF ANY BANDS AND EXACTLY
WHERE THIS WILL END UP KEEPS CHANCES BELOW LIKELY LEVELS. SOME BRIEF
MODERATE SNOWFALLS CAN BE EXPECTED IN THE HEAVIEST PRECIPITATION...
AND LOCAL AMOUNTS NEAR AN INCH SEEM PLAUSIBLE. ANY ACCUMULATING SNOW
SHOULD END WELL BEFORE SUNRISE AS THE UPPER TROF SWINGS INTO THE
MISSISSIPPI VALLEY. WESTERN AREAS SEE A QUICKLY DRYING TROPOSPHERE
THIS EVENING...BUT HIGH CLOUD RETURNS THERE LATE TONIGHT AS WARM AIR
ADVECTION ENSUES FROM THE UPPER PATTERN SHIFTING EAST. THOUGH
INSOLATION WILL BE LIMITED AS THE CLOUDS DEEPEN SATURDAY...SOUTHWEST
WINDS SHOULD SUPPORT TEMPS SEVERAL DEGREES ABOVE TODAYS LEVELS FOR
CENTRAL AND WESTERN LOCATIONS.

SHORTWAVE RIDGING AND WARM AIR ADVECTION IS EXPECTED TO BRING WARMER
TEMPS AND SUNNY SKIES TO THE AREA FOR SUNDAY. THEN THE NEXT
SHORTWAVE IS EXPECTED TO MOVE ACROSS THE CENTRAL AND NORTHERN PLAINS
BRINGING A COLD FRONT THROUGH THE AREA LATE SUNDAY NIGHT AND MONDAY
MORNING. MODELS CONTINUE TO SHOW THE BETTER MOISTURE TO THE EAST OF
THE FORECAST AREA. AND WITH THE FRONT PUSHING INTO MO BY THE LATE
MORNING HOURS...PRECIP CHANCES SHOULD BE CONFINED TO FAR EASTERN KS
DURING THE DAY MONDAY.

TUESDAY AND WEDNESDAY LOOK TO BE IN BETWEEN SYSTEMS WITH SURFACE
RIDGING BUILDING SOUTH THROUGH THE PLAINS. THIS SHOULD KEEP TEMPS
FROM WARMING UP VERY MUCH. THE NEXT BIG WEATHER MAKER LOOKS TO
IMPACT THE REGION WEDNESDAY NIGHT AND THURSDAY. BOTH THE GFS AND
ECMWF HAVE TRENDED SLIGHTLY SLOWER WITH THE UPPER CLOSED LOW AS IT
MOVES OUT OF THE SOUTHERN ROCKIES. HOWEVER THE GFS REMAINS SLIGHTLY
FASTER THAN THE GFS. THE OTHER TREND OF NOTE IS THE ECMWF FURTHER
NORTH WITH THE TRACK OF THE LOW PRESSURE SYSTEM. THIS COMPLICATES
THE FORECAST OF PRECIP TYPE QUITE A BIT. INITIALLY WITH THE COLD
SURFACE RIDGE IN PLACE WEDNESDAY...GFS FORECAST SOUNDINGS SUPPORT
ALL SNOW WEDNESDAY EVENING. HOWEVER BOTH MODELS SHOW STRONG WARM AIR
ADVECTION ALOFT AND A WARM NOSE DEVELOPING THROUGH THE NIGHT WITH
SURFACE TEMPS REMAINING IN THE 20S AND LOWER 30S. AS THE WARM AIR
ADVECTION DEVELOPS...FREEZING RAIN AND SLEET BECOME POSSIBLE WHILE
SURFACE TEMPS ARE BELOW FREEZING. ON TOP OF THIS IS THE POTENTIAL
FOR MID LEVEL DRY AIR TO WRAP UP IN THE SYSTEM AND FOR THE SOUNDINGS
TO LOOSE SATURATION WITHIN THE DENDRITIC GROWTH LAYER ADDING TO THE
POTENTIAL FOR FREEZING RAIN. REALLY THE TRACK OF THE SYSTEM DOES NOT
FAVOR AN ALL SNOW EVENT FOR THE BULK OF THE FORECAST AREA.
CONFIDENCE IN TRYING TO NAIL DOWN PRECIP TYPE IS VERY LOW AT THIS
POINT GIVEN THAT IT IS 6 DAYS OUT...BUT THINK THAT THE PROBABILITY
OF MIX WINTRY PRECIP IS HIGH ENOUGH THAT IT SHOULD BE MENTIONED IN
THE FORECAST. ONE SHOULD NOT GET CAUGHT UP ON WHERE THE FORECAST HAS
THE RAIN/SNOW LINE /WHICH IS LIKELY TO FLUCTUATE IN THE COMING
DAYS/...BUT THAT THERE IS THE POTENTIAL FOR A MIXED BAG OF PRECIP.
THINGS THAT COULD CHANGE THIS IS IF THE MAGNITUDE OF LOW LEVEL WARM
AIR ADVECTION WERE TO INCREASE AND RAISE SURFACE TEMPS ABOVE
FREEZING OR IF THE STORM SYSTEM TRENDS SOUTH AGAIN. IN ANY CASE IT
LOOKS TO BE MESSY.

WOLTERS

.AVIATION...

KTOP AND KFOE WILL REMAIN UNDER VFR STRATUS AND AT TIMES MVFR
STRATUS WITH OCCASIONAL LIGHT SNOW OR FLURRIES THROUGH AT LEAST
12Z. KMHK SHOULD REMAIN WEST OF THE STRATUS DECK THIS MORNING. VFR
STRATUS MAY FORM AT THE TAF SITES BY AFTERNOON.

GARGAN

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

AREA FORECAST DISCUSSION

NWS JACKSON KY

103 PM EST SAT FEB 16 2013

.UPDATE...
ISSUED AT 103 PM EST SAT FEB 16 2013

SCATTERED SNOW SHOWERS ARE PRESENTLY RAMPING UP AS THE SHORTWAVE
ENERGY DIVES SOUTHEAST INTO EASTERN KENTUCKY. HRRR SEEMS TO HAVE A
PRETTY GOOD HANDLE ON THINGS THIS AFTERNOON AND SHOWS A SUBSTANTIAL
WEAKENING TREND AROUND SUNSET THIS EVENING AS WE WOULD EXPECT.
THUS...GOING TO KEEP THE HIGHEST POPS IN THE NEXT 2 TO 4 HOURS...THEN
TRAIL THINGS BACK TO FLURRIES TONIGHT. BASED ON THE LACK OF ACTIVITY
UPSTREAM...THE ONLY SUPPORT FOR ANY ACTIVITY TONIGHT WILL BE UPSLOPE
FLOW INTO THE HIGHER TERRAIN. MADE SOME ADJUSTMENTS TO TIMING AND
TRENDS...BUT NO FORECAST UPDATE IS NEEDED AT THIS TIME.

UPDATE ISSUED AT 950 AM EST SAT FEB 16 2013

STILL DEALING WITH SOME FLURRIES NEAR THE VIRGINIA BORDER...WHICH
REMAINS COVERED WITH ONGOING FORECAST. OTHERWISE...LATEST HI RES
MODEL GUIDANCE SUGGEST A SLIGHTLY SLOWER ONSET OF SNOW SHOWER
ACTIVITY THIS AFTERNOON...SO HAVE SLOWED THINGS DOWN A BIT. SNOW
ACCUMULATIONS WILL BE HARD TO COME BY GIVEN SURFACE TEMPERATURES NEAR
FREEZING. THE EXCEPTION WILL BE IN THE HIGH TERRAIN NEAR THE VIRGINIA
BORDER WHERE UP TO A HALF INCH OF SNOW MAY BE POSSIBLE. OUTSIDE OF
THESE MINOR CHANGES...FORECAST IS IN GOOD SHAPE.

UPDATE ISSUED AT 740 AM EST SAT FEB 16 2013

GRIDS WERE UPDATED BASED ON THE LATEST TEMPERATURE AND DEWPOINT
TRENDS. FLURRIES WERE ALSO PUT IN IN THE WEATHER GRIDS INITIALLY NEAR
THE VA BORDER PER RADAR IMAGERY AND COOP REPORTS. OTHERWISE...THE
FORECAST FOR TODAY STILL REMAINS ON TARGET.

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 355 AM EST SAT FEB 16 2013

BEHIND A COLD FRONT THAT CROSSED THE REGION ON FRI EVENING...THE
REGION REMAINS IN NW TO NORTHERLY FLOW IN THE LOW LEVELS AND UNDER THE
INFLUENCE OF A DEEPENING TROUGH OVER THE EASTERN CONUS. LOW LEVEL
MOISTURE IS RATHER LIMITED...BUT RADAR RETURNS HINT THAT SOME
FLURRIES MAY BE FALLING FROM THE STRATOCU OVER THE BIG SANDY REGION
AND NEAR THE VA BORDER.

A FEW FLURRIES HAVE BEEN INSERTED IN THE GRIDS PRIOR TO DAWN OVER THE
SOUTHEASTERN CWA IN LINE WITH RECENT RADAR TRENDS. OTHERWISE...A
SHORTWAVE TROUGH WORKING THROUGH AN EASTERN CONUS TROUGH WILL
APPROACH THE REGION TODAY...BRINGING A BIT OF MOISTURE WITH IT...BUT
AS NOTED BY THE PREVIOUS FORECASTER...MOISTURE WILL BE RATHER
SHALLOW. HOWEVER...WITH THE APPROACH OF THE SHORTWAVE TROUGH...COLD
AIR ADVECTION SHOULD LEAD TO STEEPENING LAPSE RATES...AND THE GENERAL
MODEL CONSENSUS IS FOR A PERIOD OF SCATTERED SNOW SHOWERS FROM AROUND
MIDDAY THROUGH EARLY EVENING. BEFORE AND AFTER THIS POINT...FLURRIES
OR ISOLATED SNOW SHOWERS WILL BE POSSIBLE. A COUPLE OF ADDITIONAL
DISTURBANCES AND LINGERING NORTHWEST UPSLOPE FLOW WILL LEAD TO A
THREAT OF A BIT BETTER COVERAGE OF SNOW SHOWERS OVER THE EASTERN CWA
AND NEAR THE VA BORDER DURING MID TO LATE EVENING AND POSSIBLY TOWARD
DAWN ON SUNDAY. ANY SNOW THAT FALLS WILL HAVE A HIGH SNOW TO LIQUID
RATIO PERHAPS AS HIGH AS 20 TO 1...BUT INCREASING SUN ANGLE AND TEMPS
NEARING THE FREEZING MARK SHOULD KEEP ACCUMULATIONS RATHER MINIMAL IN
THE LOWER ELEVATIONS BELOW 1500 FEET TO A BRIEF DUSTING OR COATING OF
SNOW. AT 1500 FEET OR ABOVE AS MUCH AS A HALF OF AN INCH COULD OCCUR
AND ABOVE 2000 FEET AN INCH TO LOCALLY MORE ABOVE 3000 FEET CANNOT BE
RULED OUT FROM THIS.

MOISTURE SHOULD BECOME SHALLOWER BY SUN MORNING AND THIS COMBINED
WITH TEMPS STARTING TO WARM SHOULD END THE THREAT FOR ANY FLURRIES BY
MIDDAY ON SUNDAY. HOWEVER...STRATOCU MAY LINGER LONGER THAN SUGGEST
BY THE 0Z GFS...POSSIBLY INTO THE AFTERNOON AS SUGGESTED BY THE 6Z
NAM. FOR THIS FORECAST...HELD ONTO THE THREAT OF FLURRIES INTO THE
DAY ON SUN IN THE SOUTHEAST AND WENT MORE PESSIMISTIC ON TIMING OF
THE CLEARING ON SUN AS WELL.

AS FOR TEMPERATURES...COLD AIR ADVECTION SHOULD LEAD TO MIN T LIKELY
AFTER SUNRISE THIS MORNING AND MAX T SHOULD BE MORE ON THE ORDER OF
THE 3 HOURLY TEMPS IN THE MOS GUIDANCE AND A FEW DEGREES BELOW MOS
GUIDANCE MAX T. THE PREVIOUS FORECAST MAX T ALREADY HAD THIS IDEA...SO
VERY LITTLE CHANGE WAS MADE. MIN T TONIGHT WERE NOT CHANGED MUCH FROM
THE PREVIOUS FORECAST EITHER AND THEY SHOULD BE ON THE ORDER OF 10
DEGREES BELOW NORMAL. 850 MB TEMPS WILL BE -10C TO -15C WELL INTO THE
DAY ON SUN AND MAX T WILL BE SIMILAR TO SAT...ESPECIALLY IN THE
CENTRAL AND EASTERN CWA WHERE STRATOCU SHOULD BE MOST PERSISTENT. IF
THE LOW CLOUDS LINGER AS THE 6Z NAM SUGGESTS IN THE CENTRAL AND EAST
THEN MAX T MIGHT NOT REACH THE FREEZING MARK IN MANY LOCATIONS IN THE
EASTERN PART OF THE CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 358 AM EST SAT FEB 16 2013

THE MODELS REMAIN IN GOOD AGREEMENT WITH A PROGRESSIVE BUT FAIRLY
AMPLIFIED PATTERN TO CONTROL ACROSS THE CONUS THROUGH THE LONG TERM.
A DEPARTING DEEP UPPER LEVEL LOW WILL START OUT ACROSS NEW
ENGLAND...WITH THE OHIO AND TENNESSEE VALLEYS ENJOYING A BRIEF DRY
SPELL THANKS TO A TRANSIENT UPPER LEVEL RIDGE. TEMPERATURES WILL
RETURN TO ABOVE NORMAL FOR MONDAY...WITH GUIDANCE TRENDING A BIT
WARMER STILL...WITH HIGHS INTO THE MID 50S.

A SHORT WAVE TROUGH WILL THEN DIG ACROSS THE NORTHERN PLAINS AND THE
NORTHERN GREAT LAKES REGION THROUGH TUESDAY...ESCORTING A COLD FRONT
THROUGH EASTERN KENTUCKY MONDAY NIGHT INTO EARLY TUESDAY MORNING.
THERE ARE STILL SOME TIMING DIFFERENCES WITH THE FRONT...WITH THE
ECMWF REMAINING THE SLOWEST AND THE MAJORITY OF THE REMAINING
GUIDANCE MORE PROGRESSIVE. AS SUCH...HAVE CONTINUED TO CENTER THE
HIGHEST POPS DURING THE OVERNIGHT PERIOD ON MONDAY NIGHT AND THEN
SIDED WITH THE BLENDED GUIDANCE WITH POPS DECREASING RAPIDLY FROM
WEST TO EAST TOWARDS 12Z TUESDAY.

RIDGING WILL BRING MORE DRY WEATHER TO THE AREA FROM TUESDAY
AFTERNOON THROUGH AT LEAST THURSDAY MORNING...ALTHOUGH WITH THE
SURFACE HIGH CENTERED TO THE NORTH...TEMPERATURES WILL REMAIN BELOW
NORMAL...WITH HIGHS RETREATING TO THE LOW AND MID 40S. BY
THURSDAY...THE NEXT SYSTEM TAKES AIM AT THE AREA...THIS TIME OUT OF
THE CENTRAL PLAINS...WITH A WARM FRONT THREATENING OUR AREA WITH
OVERRUNNING PRECIPITATION BY LATE THURSDAY AFTERNOON. THE MODELS
HAVE GENERALLY TRENDED SLOWER WITH THIS SYSTEM COMPARED TO 24 HOURS
AGO...ESPECIALLY THE GFS. AS SUCH...HAVE KEPT THE MAIN SHOT OF THE
RAIN RESERVED FOR THURSDAY NIGHT...ALIGNING CLOSE TO THE BLENDED
GUIDANCE OUTPUT. BY FRIDAY...SOME SHOWERS MAY LINGER IN THE
MORNING...WITH IMPROVING CONDITIONS BY AFTERNOON AND TEMPERATURES
RETURNING TO ABOVE NORMAL READINGS IN THE 50S UNDER FAIRLY BRISK
SOUTHWEST WINDS.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 103 PM EST SAT FEB 16 2013

A WEAK DISTURBANCE WILL BRING GRADUALLY LOWERING CEILINGS INTO
EASTERN KENTUCKY TODAY INTO THIS EVENING. HOWEVER...IT LOOKS LIKE THE
WORSE CONDITIONS EXPECTED WILL BE 2500 FOOT MVFR CIGS. SOME QUESTION
AS TO HOW LONG THE LOWER CIGS MAY PLAGUE THE AREA AS THERE IS QUITE A
BIT OF DRY AND CLEARING UPSTREAM. THUS...AFTER THIS EVENING...SKY
FORECAST TONIGHT REMAINS VERY UNCERTAIN. SNOW SHOWER ACTIVITY THIS
AFTERNOON WILL TRAIL OFF TO FLURRIES TONIGHT. COULD BE A FEW STRONG
WIND GUST OUT OF THE WEST-NORTHWEST TODAY...WITH STEADY WEST-
NORTHWEST WINDS CONTINUING THROUGH TONIGHT.

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

UPDATE...KAS
SHORT TERM...JP
LONG TERM...GEOGERIAN
AVIATION...KAS

AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

352 PM EST SAT FEB 16 2013

.SHORT TERM...THIS AFTERNOON AND TONIGHT

UPPER LEVEL WAVE AND MID LEVEL COLD POOL HAVE BROUGHT SEVERAL SNOW
SQUALLS TO SOUTHEAST MICHIGAN TODAY...DROPPING A QUICK 1 TO 2 INCHES
OF SNOW ACROSS AREAS ALONG AND SOUTH OF THE INTERSTATE 69 CORRIDOR.
HOWEVER THE SURFACE TROUGH AND PV ANOMALY HAVE YET TO TRACK THROUGH
SOUTHEAST MICHIGAN. THESE FEATURES WILL TRACK THROUGH DURING THE
EVENING HOURS AND TURN WINDS TO A NORTHERLY DIRECTION...BRINGING
COOLER AIR AND LAKE MOISTURE IN FROM LAKE HURON. ALTHOUGH THE DTX
HIRES WRF RUNS DEVELOP AN IMPRESSIVE LAKE EFFECT BAND THAT TRACKS
THROUGH THE THUMB REGION BETWEEN 21Z AND 06Z...MODEL INITIALIZATION
IS VERY POOR AS THE 20Z PANEL INDICATES THERE SHOULD BE AN
IMPRESSIVE BAND JUST OFFSHORE OF HURON COUNTY...WHICH BY THE VISIBLE
SATELLITE IMAGERY IS FAR FROM REALITY. THIS FAILURE IN THE MODEL
LOOKS TO BE THE FAILURE OF A MESOLOW TO DEVELOP ACROSS CENTRAL LAKE
HURON...INSTEAD THE LAKE EFFECT IS IN A NORTHWEST TO SOUTHEAST
ORIENTATION BEHIND THE MAIN SURFACE TROUGH. THIS IS ACTUALLY
DEPICTED RATHER WELL BY THE HRRR MODEL WHICH BRINGS THIS FEATURE
SOUTH THROUGH THE EARLY EVENING HOURS AND DEVELOPS A NORTH-SOUTH
BAND OF LAKE EFFECT SNOW ACROSS THE EASTERN THUMB WITH SIGNIFICANT
ASSISTANCE FROM CONVERGENCE AS NORTH-NORTHWEST WINDS OVER THE LAKE
CONVERGE WITH NORTHEASTERLY WINDS ACROSS SOUTHERN LAKE HURON. THIS
SETUP WOULD BRING SEVERAL INCHES OF ACCUMULATING SNOW TO SANILAC AND
ST. CLAIR COUNTIES DURING THE EVENING HOURS UNTIL LAKE WINDS TURN
MORE NORTHERLY AND CONVERGENCE ALONG THE LAKE BECOMES BROADER. TO
ADD TO THE CONFUSION THE NAM MODEL IS VERY BRIEF WITH THE
CONVERGENCE AND KEEPS MOST OF THE LAKE EFFECT SNOW OFFSHORE DURING
THE EVENING HOURS.

GIVEN THE GOOD INITIALIZATION INCLINATION IS TO LEAN TOWARDS THE
HRRR SOLUTION AS EAST-WEST BANDS TEND TO TRANSITION TO NORTH-SOUTH
AS THEY ENCOUNTER THE TOPOGRAPHY OF THE THUMB REGION...HOWEVER
CANNOT RULE OUT THE POSSIBILITY OF A MESOLOW FORMING AND TRACKING
FARTHER INLAND THAN SANILAC AND ST. CLAIR COUNTIES. THEREFORE WILL
HANG ONTO THE WINTER WEATHER ADVISORY FOR THE THUMB REGION AND LET
LATER SHIFTS PARE DOWN THE HEADLINE AS THE NATURE AND ORIENTATION OF
THE LAKE EFFECT BECOME APPARENT DURING THE EVENING HOURS. THE
PREVIOUS FORECAST AMOUNTS STILL LOOK SOLID IN THIS REGION WITH A
GOOD 2 TO 4 INCHES EXPECTED WITH ISOLATED 6 INCH AMOUNTS NEAR THE
LAKE HURON SHORELINE AREAS.

.LONG TERM...SUNDAY THROUGH FRIDAY

VERY STRONG NEGATIVE POTENTIAL VORTICITY ADVECTION FROM RETREATING
LARGE WAVELENGTH UPPER LEVEL TROUGH WILL LEAD TO RAPID 1000-500MB
GEOPOTENTIAL HIGH RISES OVER SOUTHEASTERN MICHIGAN 12-00Z SUNDAY.
THE MAXIMUM OF GEOPOTENTIAL HEIGHT RISES WILL REMAIN OVER THE
SOUTHERN APPALACHIANS IN RESPONSE TO THE BOMBING
NOR`EASTER...HOWEVER...HEIGHT RISE RIDGE AXIS WILL EXTEND NORTHWARD
INTO CENTRAL GREAT LAKES. REMNANT LAKE EFFECT WILL BE ONGOING OVER
SOUTH LAKE HURON THROUGH SUNDAY AFTERNOON BEFORE SWEEPING EASTWARD
DUE TO INCREASING WESTERLY COLUMN FLOW. HIGH TEMPERATURES TOMORROW
WILL BE CONSIDERABLY COLD...SOME 10-13 DEGREES BELOW NORMAL. A
RATHER RAW DAY WITH JUST ENOUGH WIND MAGNITUDE TO ALLOW FOR WIND
CHILL VALUES IN THE SINGLE DIGITS BEFORE NOON...TOPPING OUT BETWEEN
10-15 DEGREES FOR THE AFTERNOON. TYPICAL QUESTION MARK EXISTS
CONCERNING POTENTIAL FOR STRATOCUMULUS TOMORROW. THE AREAS
POSITION/PROXIMITY WITHIN EDGE OF RETREATING TROUGH AND OVERALL
ARCTIC AIRMASS SUGGESTS SUNSHINE WILL GREET US IN THE MORNING. THIS
CERTAINLY HAS SUPPORT WHEN LOOKING AT SATELLITE IMAGERY OVER
NORTHERN MINNESOTA. THE MODELED INVERSION AT ROUGHLY 5 KFT AGL IS
INTERESTING AS THE SOLUTION SHOWS NO MOISTURE TRAPPED WITHIN THE
STABLE STRATIFIED LAYER IMMEDIATELY ABOVE INVERSION BASE OR EVEN AT
THE INVERSION BASE ITSELF. WILL CONTINUE WITH THE INHERITED FORECAST
WHICH CALLS FOR SUNSHINE TOMORROW.

MODELS ARE COMING INTO AN AGREEMENT WITH THE SYSTEM THAT WILL
APPROACH THE AREA MONDAY NIGHT. OVERALL...SYSTEM DYNAMICAL SUPPORT
APPEARS ABOVE AVERAGE AS THE SOUTHERN EXTENSION OF THE MIDLEVEL
TROUGH WILL BECOME LINKED TO SOUTHERN STREAM JET STREAM ENERGY OVER
THE FOUR CORNERS AREA SUNDAY NIGHT. THE TROUGH AXIS WHICH WILL BEGIN
AT A POSITIVE TILT WILL TURN NEUTRAL MONDAY NIGHT AND EVENTUALLY
NEGATIVE BY TUESDAY MORNING. THE PRECEDING WARM AIR ADVECTION...WING
OF ISENTROPIC LIFT IS SHOWN TO BE DRY. IT WILL REQUIRE ACTUAL
MOISTURE TRANSPORT AND UPPER LEVEL JET SUPPORT TO GET PRECIPITATION
GOING. DELAYED PRECIPITATION ONSET TIMING A FEW HOURS...NOW EXPECTED
MAINLY FOR THE FIRST HALF OF MONDAY NIGHT. THE GFS SOLUTION AND
RESULTANT PRECIPITATION TYPE SEEMS HIGHLY SUSPECT GIVEN THE OVERALL
HEIGHT PATTERN AND FORECASTED WIND FIELD. REST OF THE MEDIUM RANGE
SUITE SUGGESTS THAT A SUBSTANTIAL WARM LAYER FROM SFC-5 KFT AGL WILL
SLIDE IN SUPPORTING A RAPID TRANSITION TO RAIN. FROM THIS VANTAGE
POINT THIS SYSTEM HAS THE POTENTIAL TO BECOME A HIGHER IMPACT WIND
EVENT. RIGHT NOW...FORECASTED VALUES OF UPWARDS OF 30 KNOTS SEEMS
GOOD...WITH ALL THE MAIN FEATURE SLIGHTLY OUT OF PHASE. SUBSEQUENT
SHIFTS CAN FINE TUNE THIS.

.MARINE...

OTHER THAN AN ACTIVE SNOW SHOWER PATTERN TONIGHT...MARINE CONDITIONS
WILL BE FAVORABLE THROUGH SUNDAY IN TERMS OF WIND OVER ALL MARINE
AREAS AND WAVES OVER THE OPEN WATERS OF LAKE HURON. AFTER THAT...A
STRONG LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS
AND MIDWEST AND MOVE THROUGH THE GREAT LAKES MONDAY AND TUESDAY.
MILD AIR SPREADING NORTHWARD AHEAD OF THE SYSTEM WILL BRING RAIN TO
ALL AREAS EXCEPT THE FAR NORTH REACHES OF LAKE HURON. A STRONG COLD
FRONT IS EXPECTED TO BRING A SHARP WESTERLY WIND SHIFT TUESDAY
MORNING BUT SPEEDS ARE EXPECTED TO REMAIN BELOW GALE FORCE FOR
NOW. STRONG NORTHWEST WIND TRAILING THE FRONT WILL EASE IN SPEED
DURING WEDNESDAY.

.AVIATION...ISSUED 1226 PM EST SAT FEB 16 2013

//DISCUSSION...

CEILINGS LOOK TO BE PREDOMINATELY MVFR AS A WEAK SURFACE LOW AND
ASSOCIATED COLD FRONT SINK SOUTH THROUGH THE AREA THIS AFTERNOON AND
EVENING. THERE WILL BE A CONTINUED THREAT FOR SNOW SHOWERS...WITH
CONVECTIVE NATURE TO THE ACTIVITY LEAD TO BRIEF IFR BURSTS...LEADING
TO 1 TO 3 INCHES OF ACCUMULATIONS BY THE TIME THE SNOW ENDS LATE
THIS EVENING. SKIES LOOK TO BE CLEARING OUT OVERNIGHT AS SURFACE
HIGH SETTLES OVER WESTERN LOWER MICHIGAN...MAINTAIN GENERALLY LIGHT
WINDS. WINDS TODAY WILL ALSO BE VERY LIGHT AND VARIABLE WITH THE
SURFACE LOW TRACKING THROUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET THROUGH THIS
EVENING.

* HIGH CONFIDENCE IN PRECIPITATION TYPE BEING SNOW.

* MEDIUM CONFIDENCE IN CIGS/VSBYS ABOVE 200 FT AND 1/2SM THIS
AFTERNOON.

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY...MIZ049-MIZ054-MIZ062...UNTIL 10 PM
SATURDAY.

WINTER WEATHER ADVISORY...MIZ055-MIZ063...UNTIL 2 AM SUNDAY.

LAKE HURON...NONE.

LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
AVIATION.....KURIMSKI

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

AREA FORECAST DISCUSSION

NWS GRAND RAPIDS MI

132 PM EST SAT FEB 16 2013

.SYNOPSIS...
ISSUED AT 330 AM EST SAT FEB 16 2013

OCCASIONAL SNOW SHOWERS WILL CONTINUE TODAY AND INTO THIS EVENING.
THE SNOW WILL BE HEAVY AT TIMES. LAKE SHORE AREAS WILL PICK UP
ANOTHER 2 TO 4 INCHES...WHILE INLAND AREAS SEE 1 TO 2 INCHES. THE
SNOW IS EXPECTED TO DIMINISH AFTER MIDNIGHT.

BY MONDAY LOW PRESSURE WILL MOVE INTO THE UPPER MIDWEST. THIS
SYSTEM WILL BRIEFLY BRING TEMPERATURES UP TO AROUND 40 BY MONDAY
AFTERNOON. A PERIOD OF RAIN IS EXPECTED MONDAY AFTERNOON...THAT
WILL TURN TO SNOW MONDAY NIGHT AND CONTINUE ON TUESDAY. MORE SNOW
LOOKS LIKELY BY THURSDAY NIGHT AND FRIDAY.

.UPDATE...
ISSUED AT 132 PM EST SAT FEB 16 2013

AS DISCUSSED IN THE RECENT WSW UPDATE...EXPECT MASON AND OCEANA
TO SEE A MARKED DROP IN SNOW INTENSITY LATER THIS AFTERNOON BASED
ON RAP MODEL GUIDANCE. FOR NOW THOUGH...RADAR RETURNS AT
SIGNIFICANT RANGE BEYOND LUDINGTON COMBINED WITH IMPRESSIVE BANDS
NOTED ON IR SATELLITE INDICATE INTENSE SNOWFALL IS STILL LIKELY
ONGOING.

HAVE DROPPED LAKE...NEWAYGO...AND KENT COUNTIES FROM THE ADVISORY.
ACCUMULATIONS WERE LIMITED IN THESE AREAS. THE REMAINING THREE INLAND
COUNTIES (BARRY...KALAMAZOO... AND CALHOUN) ARE KEPT IN AN ADVISORY
TO ACCOUNT MOSTLY FOR RAPID VISIBILITY CHANGES. BIV RECENTLY
DROPPED TO 1/4 MILE UNDER ONE OF THE STRONGER BANDS.

ACCUMULATING SNOW SHOULD NOT BE SO MUCH OF AN ISSUE AWAY FROM THE
LAKESHORE THE REST OF TODAY. PRECIPITATION GENERALLY APPEARS MORE
CELLULAR ON RADAR. THIS COMBINED WITH MID-FEBRUARY DAYTIME
INSOLATION IS KEEPING ACCUMULATIONS IN CHECK.

UPDATE ISSUED AT 900 AM EST SAT FEB 16 2013

AFTER FURTHER CONSIDERATION...WILL BE UPGRADING MASON AND OCEANA
TO A WARNING. RAP GUIDANCE SUGGESTS THAT AFTER A LULL THIS MORNING...
ANOTHER SIGNIFICANT BAND MAY EXTEND FROM THESE COUNTIES THROUGH
MUSKEGON...ALLEGAN...AND KALAMAZOO COUNTIES.

UPDATE ISSUED AT 848 AM EST SAT FEB 16 2013

HAVE RECEIVED RECENT 8-12" SNOW REPORTS FROM SEVERAL LOCATIONS IN
MASON AND OCEANA COUNTIES BENEATH AN AREA OF SATELLITE IR
TEMPERATURES THAT WERE COLDER THAN -30C BETWEEN 11-12Z. 830 AM
AWOS OBSERVATION AT HART INDICATES VISIBILITY BELOW 1/4 MILE.

SUSPECT STRONG FRONTOGENETIC FORCING HAS BEEN AT PLAY AS
TEMPERATURES AT RQB AND CAD HAD DROPPED AS MUCH AS 10 DEGREES OR
MORE OVER THE PAST FEW HOURS. PRESENT THINKING IS THAT FGEN
FORCING SHOULD DECREASE ALONG WITH MOST INTENSE SNOW THROUGH 10
AM. THIS IS SUPPORTED BY THE 16/09Z RUN OF THE HRRR...WHICH TAPERS
PRECIP AND MOVES IT INLAND THROUGH 15Z. BELIEVING WE ARE ON A
DOWNWARD TREND AFTER A PEAK IN SNOWFALL INTENSITY...WILL KEEP THE
ADVISORY GOING IN THIS AREA AND UPDATE WITH THE LATEST THINKING.

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

A RATHER DISORGANIZED PATTERN SO FAR EARLY THIS MORNING. A SURFACE
TROUGH HAS BEEN CROSSING THE LAKE EARLY THIS MORNING AND THE WIND
PATTERN AROUND THIS TROUGH HAS BEEN DISRUPTING ANY ORGANIZED LAKE
EFFECT BANDS. THERE HAS BEEN A PERSISTENT BAND ACROSS THE NW
COUNTIES NEAR LUDINGTON AND WHITEHALL...BUT OTHER SNOW BANDS HAVE
BEEN FAIRLY TRANSITORY...KEEPING ACCUMS DOWN.

THE SURFACE TROUGH LINGERS OVER THE AREA MUCH OF TODAY...SO FEEL WE
MAY STRUGGLE TO GET PERSISTENT LES BANDS. RAP13 LOW LEVEL
CONVERGENCE FIELDS SUGGEST THE LDM BAND MAY HOLD PAT MUCH OF THE
DAY. IF THIS HOLDS TRUE...THIS BAND COULD PUT DOWN ANOTHER FOUR
INCHES OR SO. A BETTER FLAIR UP IS INDICATED TOWARD 16Z FOR THE SW
COUNTIES AND THIS IS PAINTED TO LAST THROUGH MUCH OF THE AFTERNOON.
ALSO OF INTEREST IS A SYNOPTIC CONVERGENCE BAND THAT FLAIRS UP NORTH
OF THE SURFACE TROUGH ALONG HIGHWAY 10 BY MID TO LATE AFTERNOON
TODAY. IF THIS HOLDS TRUE THERE COULD BE A BURST OF SNOW ACROSS ALL
OF THE NORTHERN COUNTIES INTO THIS EVENING.

NEEDLESS TO SAY A RATHER COMPLEX PATTERN FOR TODAY. THOUGHT ABOUT
DROPPING SOME OF THE COUNTIES IN THE ADVISORY AS THE LAKE EFFECT
DOES NOT LOOK AS ROBUST ANYMORE. HOWEVER SINCE SNOW WILL STILL
OCCUR...IT IS SORT OF HARD TO DROP HEADLINES IN THE MIDDLE OF AN
EVENT. SO WILL LEAVE THE ADVISORY AS IS...ALTHOUGH WILL HIGHLIGHT
SLIGHTLY LESS ACCUMS. ON THE OTHER HAND...INLAND AREAS COULD SEE A
BIT MORE SNOW THEN WHAT IS CURRENTLY IN THE FORECAST DUE TO THE
SYNOPTIC FEATURES. SO HAVE BUMPED UP ACCUMS A BIT INLAND...
ESPECIAL NEAR HIGHWAY 10 TO COVER THE POSSIBLE CONVERGENCE BURST
LATE TODAY INTO THIS EVENING. THE SNOW SHOULD BE DWINDLING AFTER
MIDNIGHT AS THE SYSTEM PULLS AWAY AND INVERSION LEVELS COME DOWN.

WILL CONTINUE WITH THE CHANCE POPS ON SUNDAY ALONG THE LAKE SHORE.
WINDS WILL PIVOT FROM THE NNW EARLY IN THE DAY TO SW TOWARD MID
DAY. THIS SHOULD PUSH ANY LAKE BAND INLAND...PRODUCING A BRIEF SNOW
SHOWER MAINLY WEST OF U.S. 131.

THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE MONDAY SYSTEM...
BRINGING IT IN QUICKER. HAVE INCREASED POPS TO LIKELY BY MID TO
LATE AFTERNOON. SHOULD BE WARM ENOUGH OF MOSTLY RAIN...ALTHOUGH A
MIX SHOULD FALL OVER CENTRAL LOWER.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

ACTIVE WEATHER PATTERN NEXT WEEK WITH TWO STORMS TO WATCH. A CLIPPER
MOVES MOVES EAST MONDAY NIGHT WITH RAIN AND SNOW MIX CHANGING TO
SNOW...FOLLOWED BY WEST FLOW LAKE EFFECT SNOW FROM TUESDAY AFTERNOON
INTO WEDNESDAY.

SFC AND SHORTWAVE UPPER RIDGING MOVES IN TO END THE LAKE EFFECT ON
WEDNESDAY NIGHT...BUT THE LULL WILL BE SHORT LIVED AS A STORM TAKES
SHAPE ACROSS THE PLAINS AND MOVES NORTHEAST SPREADING A BAND OF SNOW
INTO LOWER MICHIGAN BY LATE THURSDAY. SNOW COULD BE HEAVY THURSDAY
NIGHT AS AN AREA OF STRONG UPPER LEVEL DIVERGENCE AND DEEP LIFT
MOVES OVER LOWER MICHIGAN. SNOW WILL CONTINUE ON FRIDAY AS AN UPPER
LOW MOVES ACROSS ALTHOUGH WITH LESS INTENSITY AS DEEPER LIFT AND
MOISTURE MOVES EAST.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1256 PM EST SAT FEB 16 2013

COMPLICATED SCENARIO FOR AVIATION INTERESTS THIS AFTERNOON AND
EVENING. LAKE EFFECT SNOW SHOWERS ARE ONGOING THIS AFTERNOON...
HOWEVER THERE A FEW WEAK WAVES MOVING THROUGH THAT ARE
COMPLICATING THE SITUATION AND ARE DISRUPTING TYPICAL BANDING.
KGRR AND KLAN SEEM TO BE NORTH AND EAST OF THE MORE SIGNIFICANT
SNOW SHOWERS...AND SHOULD REMAIN SO WITH ONLY SCATTERED SNOW
SHOWERS THIS AFTERNOON.

THE OTHER SITES ARE SEEING DECENT LAKE EFFECT AT TIMES. KMKG IS
SEEING MORE LAKE EFFECT BANDING...WHILE KAZO...KBTL...AND KJXN
SHOULD SEE THE EFFECTS OF THE WAVE THAT IS JUST WEST OF HASTINGS
AT 18Z. SOME LOWER IFR-LIFR CONDITIONS ARE EXPECTED WITH THIS
WAVE AT THOSE SITES...ESPECIALLY KBTL AND KJXN.

WE EXPECT SNOW SHOWERS TO GRADUALLY SHIFT OFFSHORE THIS EVENING
FROM NE TO SW AS A LAND BREEZE DEVELOPS AND THE FLOW GENERALLY
SHIFTS TO THE NE FOR A PERIOD OF TIME. THIS SHOULD ALLOW MOST AREA
TO CLEAR OUT. LATE TONIGHT...SNOW SHOWERS WILL COME BACK ONSHORE
NORTH OF KMKG AFTER 09Z...AND THESE WILL GRADUALLY SPREAD INLAND
SUN MORNING AND WEAKEN.

.MARINE...
ISSUED AT 330 AM EST SAT FEB 16 2013

WILL KEEP MARINE HEADLINE AS IS...SCA THROUGH TONIGHT.

.HYDROLOGY...
ISSUED AT 330 AM EST SAT FEB 16 2013

COLDER AIR HAS LOCKED UP ANY FURTHER SNOW MELT. WE WILL SEE A BRIEF
WARM UP ON MONDAY WITH TEMPS REACHING AROUND 40 ALONG WITH SOME
RAIN. SINCE THE WARM UP WILL BE BRIEF AND THE RAIN SHOULD BY LESS
THAN A QUARTER INCH...NO HYDRO ISSUES ARE EXPECTED. HOWEVER A FLOOD
ADVISORY REMAINS IN EFFECT FOR HIGH WATERS ON THE PERE MARQUETTE
NEAR SCOTTVILLE.

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MIZ050-056-064-071-072.

LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ065-
073.

LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ037-
043.

LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.

UPDATE...TJT
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...OSTUNO
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK

AREA FORECAST DISCUSSION

NWS GRAND RAPIDS MI

1256 PM EST SAT FEB 16 2013

.SYNOPSIS...
ISSUED AT 330 AM EST SAT FEB 16 2013

.UPDATE...
ISSUED AT 900 AM EST SAT FEB 16 2013

UPDATE ISSUED AT 848 AM EST SAT FEB 16 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1256 PM EST SAT FEB 16 2013

.MARINE...
ISSUED AT 330 AM EST SAT FEB 16 2013

WILL KEEP MARINE HEADLINE AS IS...SCA THROUGH TONIGHT.

.HYDROLOGY...
ISSUED AT 330 AM EST SAT FEB 16 2013

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MIZ050-056-064-071-072.

LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ065-
073.

LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ037-
043.

LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.

UPDATE...TJT
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...OSTUNO
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK

AREA FORECAST DISCUSSION

NWS GRAND RAPIDS MI

901 AM EST SAT FEB 16 2013

.SYNOPSIS...
ISSUED AT 330 AM EST SAT FEB 16 2013

.UPDATE...
ISSUED AT 900 AM EST SAT FEB 16 2013

UPDATE ISSUED AT 848 AM EST SAT FEB 16 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EST SAT FEB 16 2013

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 651 AM EST SAT FEB 16 2013

LAKE EFFECT SNOW SHOWERS WILL BRING AREAS OF IFR AND PATCHY LIFR
TODAY. CONDITIONS WILL VARY QUITE A BIT WITH VFR AND MVFR
PREVAILING WELL INLAND. WINDS WILL BE NORTHWEST AT OR BELOW 10
KNOTS. THE SNOW WILL BEGIN TO LET UP THIS EVENING WITH MOSTLY VFR
EXPECTED LATER TONIGHT.

.MARINE...
ISSUED AT 330 AM EST SAT FEB 16 2013

WILL KEEP MARINE HEADLINE AS IS...SCA THROUGH TONIGHT.

.HYDROLOGY...
ISSUED AT 330 AM EST SAT FEB 16 2013

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MIZ037-043-050-056-064-071-072.

LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ038-
044-057-065-073.

LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.

UPDATE...TJT
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JK
MARINE...JK

AREA FORECAST DISCUSSION

NWS KANSAS CITY/PLEASANT HILL MO

1127 PM CST Fri Feb 15 2013

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...

Short Range (Tonight through Sunday)...

Main weather concern for this period centers on the overnight period
but confined to only the western third of the CWA. One last
vorticity max/shortwave diving down the backside of a retreating
broad upper trough will drop south-southeast across eastern NE
passing just west of the MO/KS state line overnight. Satellite
imagery and radar returns suggest two vorticity maxima...one moving
into northeast NE and a second west of BIE. Features are best seen
on NAM h7 prog. Scattered snow showers a bit more widespread than
shown by NAM output while RAP looks too generous on qpf. Prefer
blending the two model outputs which results in higher pops and
expanding snow shield a bit more east. Moderately high liquid/snow
ratios show potential for a narrow swath of 1+ inches of snow over
the far western counties. Given the expected scattered coverage of
the snow prefer keeping pops under the likely category for now. Snow
will have exited the southwestern CWA by Saturday morning with
clearing from north to south.

Saturday will bring the start of a welcome warmup over the Plains
which will quickly spread east...reaching into the western counties
by the afternoon hours. A band of dense mid level clouds will spread
from west to east Saturday night and herald the arrival of the
deepening warm air advection zone. Still expecting a significant
warmup on Sunday although there may be a tighter west to east
gradient due as boundary layer winds take on a south-southeast
direction which will limit the degree of warming further east.

Medium Range (Monday through Friday)...

Next week continues to look very active, with two systems moving
through the Plains on Monday night and again from Wednesday night
through early Friday. The primary focus will be the significant
system for Wednesday night through Thursday night, which has the
potential to be a fairly major winter storm if the current track
pans out.

On Monday, a deep longwave trough will dive through the Central
Plains, driving a surface cold front through the CWA during the
daylight hours. A broad area of scattered rain showers will be
possible along and ahead of the front, but amounts will be light as
moisture return into the Plains will be quite limited. A brief mix
with snow may be possible along our eastern border if any light
precipitation can linger behind the surface boundary, but no snow
accumulation is expected.

By Wednesday night, a deep upper low will begin to eject out of the
four corners region. As it moves eastward into the southern Plains,
strong southerly flow will draw Gulf moisture into the system, which
will combine with the existing Pacific moisture and enhance
precipitation coverage and intensity as the system begins to lift
northeast. All model solutions bring the elevated warm front into at
least the southeastern two thirds of the CWA by Thursday morning but
keep cold air lingering at the surface over almost the entirety of
the area, indicating a potential for freezing rain in those areas.
Since this is a deviation from previous forecasts, have started out
with a slight chance for freezing rain on top of the primary
rain/snow mix, but the probability for ice may need to be heightened
if future forecasts look similar. As cold air wraps in behind the
850mb low, precipitation should change to all snow from west to east
during the day on Thursday, becoming all snow and lifting out of the
area after 00z Friday. Very preliminary snowfall totals range from
more than 6 inches across the northern third of the forecast area
where precipitation type is likely to be snow during the majority of
the event, to 2-3 inches in west central and eastern parts of the
CWA, then tapering to less than 2 inches in the far southwest where
rain or freezing rain will be the predominant precipitation type
during the majority of the event.

With the consistency of model solutions, both temporally and between
different model configurations, the overall potential for a winter
storm is increasing. However, precipitation types and snowfall
amounts are still somewhat uncertain and will need to be further
refined, especially as this system heads onshore early next week.

Laflin

.AVIATION...

For the 06Z TAFs...band of light snow is rapidly weakening and
pushing into west central MO, south of the KC terminals. May still
see some brief light snow and MVFR restrictions lingering at MCI/MKC
at the start of the TAF period but in general expect rapid
improvement at these terminals soon. Behind the snow there is a
lingering swath of MVFR stratocumulus over northeast KS that is
skirting the STJ/MCI/MKC corridor. This may clip these terminals over
the next few hours but otherwise expect no significant aviation
concerns for the next 24 hours.

Hawblitzel

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

WFO EAX

AREA FORECAST DISCUSSION

NWS BILLINGS MT

853 PM MST SUN FEB 17 2013

.SHORT TERM...VALID FOR MON AND TUE...

THE FORECAST REMAINS CHALLENGING WITH UNSTABLE NORTHWEST FLOW AND
OROGRAPHIC INFLUENCES IN PLAY TONIGHT AND MON MORNING. WE DID NOT
MAKE ANY EARTH-SHATTERING CHANGES TO THE FORECAST IN LIGHT OF THE
UNCERTAINTY...AND SO OUR CURRENT WINTER WEATHER ADVISORIES REMAIN
IN PLACE. HOWEVER...WE DID MAKE A FEW ADJUSTMENTS TO POPS THROUGH
12 UTC BASED ON OBSERVATIONAL TRENDS AS OF 03 UTC. THAT MEANT THE
POPS WERE REDUCED IN MANY PLACES THROUGH MIDNIGHT...AND WERE KEPT
IN THE 40 AND 50 PERCENT RANGE FOR SOUTHEASTERN MT THROUGH 12 UTC
WITH A SCATTERED COVERAGE OF SNOW SHOWERS THERE. SYNOPTIC FORCING
IN THAT PART OF THE STATE WILL BE WEAK OVERNIGHT.

MEANWHILE...MOISTURE CHANNEL AND INFRARED SATELLITE IMAGES SHOW A
SECOND SHORT WAVE TROUGH MOVING SOUTHEAST THROUGH THE GREAT FALLS
AREA AS OF MID EVENING. MOST MODEL SOLUTIONS IN THE PAST 24 HOURS
OR MORE HAVE EXPECTED THIS WAVE...AND EVEN THE 00 UTC NAM REVEALS
AN AREA OF MODERATE 500-300 HPA Q-VECTOR FORCING CROSSING CENTRAL
MT INTO MON MORNING. WE THUS EXPECT AN UPTICK IN PRECIPITATION BY
12 UTC OVER SOUTH CENTRAL MT...ESPECIALLY WHERE ALIGNMENT OF LOW-
LEVEL FLOW AND OROGRAPHICS FAVOR BANDS DOWNSTREAM OF THE MOUNTAIN
RANGES. ONE SUCH BAND IS OCCURRING DOWNSTREAM OF THE CRAZIES THIS
EVENING...AND IT/S POSSIBLE THAT ANOTHER ONE COULD FORM CLOSER TO
BILLINGS BY MORNING DOWNWIND OF THE SNOWY RANGE. THE RAP MODEL IS
ACTUALLY HINTING AT THAT WITH ITS LAST SEVERAL SOLUTIONS. WE WILL
NEED TO BE WARY OF THAT POTENTIAL SINCE EVEN LIGHT AMOUNTS DURING
THE MORNING RUSH HOUR MAY HAVE IMPACT...BUT PREDICTABILITY OF ANY
MESOSCALE FEATURE LIKE THAT IS LOW SO IT IS HARD TO ADVERTISE THE
POSSIBILITY TOO HARD IN OUR CURRENT FORECAST PRODUCTS.

FINALLY...WHERE OUR ADVISORIES ARE CONCERNED...SINCE THERE IS NOT
ANY CHANGE IN THINKING FROM EARLIER TODAY...WE HAVE NO CONFIDENCE
IN DROPPING ANY OF THE HEADLINES. IT IS FAR FROM A SLAM-DUNK THAT
LIVINGSTON WILL GET IN ON THE SNOW...BUT IN SOME RESPECTS THE RED
LODGE ADVISORY IS LOOKING BETTER AND BETTER ALL THE TIME. UPSLOPE
IN THAT AREA IS TRICKY TO PIN DOWN SINCE IT DEPENDS A LOT ON WIND
DIRECTIONS FALLING INTO A NARROW RANGE...BUT A HIGH RESOLUTION...
LOCALLY-RUN WRF SIMULATION FROM 18 UTC MADE A BIG JUMP IN SHOWING
UP TO 0.50 INCHES OF LIQUID-EQUIVALENT FOR RED LODGE BY NOON MON.
THAT WRF RUN ACTUALLY VERIFIED WELL WITH THE LAST TWO SNOW EVENTS
AT RED LODGE...SO ITS SOLUTION /WHICH IMPLIES HIGHER SNOW AMOUNTS
THAN CURRENTLY FORECAST/ IS CERTAINLY A POSSIBLE OUTCOME. SCHULTZ

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

ONLY MINOR ADJUSTMENTS TO THE EXTENDED FORECAST. STRONG STORM
SYSTEM FOR WEDNESDAY THROUGH FRIDAY CONTINUES TO TAKE A SOUTHERN
TRACK KEEPING MUCH OF ITS PRECIPITATION POTENTIAL AWAY FROM THE
AREA. HOWEVER COLD ADVECTION AND DIFFLUENT FLOW ALOFT SHOULD BE
ENOUGH FOR CHANCE TYPE POPS FOR THE LOWER ELEVATIONS EACH DAY WITH
LIKELY POPS FOR SOUTHERN MOUNTAIN ZONES. MODELS CONTINUE TO
STRUGGLE WITH THE TRACK OF THE SYSTEM AND THE EVOLUTION OF THE
WESTERN TROF AFTER THURSDAY. LATEST RUNS NOW BEND THE SYSTEM NORTH
AND SLIGHTLY WEST ON FRIDAY BRINGING IT INTO THE DAKOTAS. IF THIS
VERIFIES WILL NEED HIGHER POPS OVER EASTERN AREAS FRIDAY INTO
SATURDAY...BUT WITH INCONSISTENCY HAVE LINED UP WITH EASTERN
NEIGHBORS AND KEPT LOW POPS IN PLACE. WITH ENERGY DRAGGING JET
STREAM WELL INTO THE DESERT SOUTHWEST MUCH COLDER THAN AVERAGE
TEMPERATURES LOOK GOOD FOR WEDNESDAY INTO FRIDAY. SECOND SYSTEM
DROPPING INTO IDAHO SATURDAY INTO SUNDAY WILL KEEP TROF OVER THE
AREA AND BRING A BETTER CHANCE OF PRECIPITATION WEST...HOWEVER
UNTIL THE MODELS GAIN TRACTION ON WHAT TO DO WITH DOWNSTREAM
SYSTEM HAVE LITTLE CONFIDENCE IN THIS SYSTEMS TRACK OR TIMING.
RETAINED BELOW AVERAGE TEMPERATURES AND CLIMO TYPE PRECIPITATION
CHANCES FOR THE LATER EXTENDED PERIODS. CHAMBERS

.AVIATION...

AREAS OF LIGHT SNOW ALONG THE MONTANA WYOMING BORDER AND INTO
SHERIDAN COUNTY WYOMING WILL GRADUALLY COME TO AN END BY
MIDNIGHT. MOUNTAIN AND FOOTHILL LOCATIONS MAY SEE AREAS OF IFR OR
LOWER CONDITIONS THROUGH MIDNIGHT. ELSEWHERE MAINLY VFR
CONDITIONS ARE EXPECTED THROUGH MIDNIGHT.

AREAS OF LIGHT SNOW ARE EXPECTED TO REDEVELOP WEST OF A KSHR TO
KBIL LINE BY DAYBREAK AND CONTINUE THROUGH NOON. WITHIN THESE
AREAS...MVFR TO IFR CONDITIONS CAN BE EXPECTED. MOUNTAINS AND
PASSES ARE EXPECTED TO BE OBSCURED THROUGH MONDAY AFTERNOON. MEIER

.PRELIMINARY POINT TEMP/POPS...

MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 022/032 017/030 016/027 014/027 016/034 020/035 020/035
55/J 00/B 23/S 32/S 21/B 11/B 32/J
LVM 019/034 019/032 016/028 013/028 015/033 016/034 016/034
82/J 02/S 34/S 32/S 22/S 22/J 33/J
HDN 022/030 013/029 015/028 011/027 011/032 015/033 017/033
65/J 00/B 13/S 42/S 21/B 11/B 33/J
MLS 021/026 012/027 011/026 011/025 012/027 014/029 015/029
53/J 00/U 03/S 32/S 22/S 11/B 22/J
4BQ 022/027 010/027 012/028 012/026 011/027 013/029 015/029
84/J 00/U 03/S 43/S 22/S 11/B 23/J
BHK 018/020 003/020 005/020 007/020 006/022 010/024 013/021
55/J 00/N 02/S 33/S 32/S 11/B 22/J
SHR 020/029 009/030 013/029 010/027 010/032 014/033 015/033
74/J 00/B 14/S 43/S 22/S 12/J 44/J

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 AM MST MONDAY FOR
ZONES 56-64>66.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 PM MST MONDAY FOR
ZONE 98.

$$
WEATHER.GOV/BILLINGS

AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

1159 AM CST SAT FEB 16 2013

.UPDATE...
ISSUED AT 1159 AM CST SAT FEB 16 2013

RADAR ACTIVITY IS NOW CONFINED TO AREAS EAST OF A KANW TO KBBW
LINE...WITH THE WARM FRONT CURRENTLY FROM NEAR KBIR TO KANW TO
KBBW. OBSERVATIONS ARE SHOWING VERY LIGHT SNOW OR FLURRIES FROM
THIS ACTIVITY AND AS THE FRONT CONTINUES TO MOVE EAST THIS
AFTERNOON...DO EXPECT ANY ACCUMULATING SNOW TO END IN THE NEXT FEW
HOURS WITH ONLY FLURRIES THROUGH THE REMAINDER OF THE AFTERNOON.
TEMPERATURES HAVE BEEN CLIMBING STEADILY THROUGH THE MORNING WITH
READINGS IN THE MID TO UPPER 40S ACROSS MUCH OF THE AREA BY 18Z.
THE EXCEPTION IS AREAS WHERE SNOW COVER REMAINS OVER THE WESTERN
AND NORTHERN SANDHILLS...WITH LOWER TEMPERATURES IN THOSE AREAS.
ALSO...BREEZY WINDS WILL OCCUR THROUGH THE AFTERNOON AS THE
BOUNDARY LAYER MIXES DOWN SOME OF THE STRONGER WINDS ALOFT. MAY
MIX A BIT HIGHER THAN 850MB THIS AFTERNOON...AND WITH WINDS AT
THAT LEVEL OF 25KTS TO 35KTS...WOULD EXPECT A FEW HOURS OF SOME
PRETTY BREEZY CONDITIONS THIS AFTERNOON.

.UPDATE...

MULTI MODEL BLEND OF RUC...HRRR...GEMREG...SREF...NAM...ECM
PRODUCED WARMER TEMPS TODAY AND SUNDAY AS WARRANTED BY THE KUNR
SOUNDING. NO DISCERNIBLE CHANGE OCCURRED TO THE ONGOING WEATHER
USING THE SAME BLEND. A NEW FCST IS OUT...KIML COULD REACH 60F ON
SUNDAY. OVERALL THE SNOW MOVES OUT QUICKLY THIS MORNING WITH
CLEARING TO FOLLOW JUST A RAPIDLY ALONG AND WEST OF HIGHWAY 83.
CLOUDS STAY IN LONGER EAST OF 83 AS ANOTHER BATCH OF CLOUDS MOVES
DOWN FROM THE DAKOTAS LATER THIS MORNING.

.PREV DISCUSSION... /ISSUED 413 AM CST SAT FEB 16 2013/

.UPDATE...

RAN A BLEND OF ECM...GEMREG...NAM...RUC AND HRRR FOR THE ONGOING
LIGHT SNOW ASSOCIATED WITH THE WARM FRONT ACROSS WRN NEB. THIS
STILL GIVES LESS THAN AN INCH ACCUMULATION BUT THE RADAR IS
LOOKING PRETTY ROBUST SO WE WILL HAVE TO WAIT FOR THE SNOW TO PASS
OVER AN OBSERVATION SITE.

THE LATEST DETAILS ON THE WEDS-THUR STORM ARE OUT IN THE FORM OF A
SPECIAL WEATHER STATEMENT.

PREV DISCUSSION... /ISSUED 337 AM CST SAT FEB 16 2013/

SHORT TERM...THROUGH 00Z MONDAY. THE GEMREG...NAM...RUC AND HRRR
SHOW A DEVELOPING WARM FRONT MOVING EAST THROUGH NRN NEB THIS
MORNING AND WEAKENING DURING THE AFTN. RADAR SUPPORTS THE
DEVELOPMENT OF SCATTERED SNOW SHOWERS. SKIES SHOULD CLEAR OUT
BEHIND THE WARM FRONT THROUGHOUT THE MORNING...AFTN AND EVENING
HOURS. TEMPERATURES TODAY RANGE FROM NEAR 40 NORTHEAST TO MID 50S
SOUTHWEST. LOW THROUGHOUT THE FCST AREA TONIGHT FALL TO AROUND 20.

LONG TERM...00Z MONDAY AND BEYOND. MAIN FOCUS IN THE EXTENDED
PERIOD REMAINS CENTERED ON THE POTENTIALLY SIGNIFICANT WINTER
STORM POISED TO ARRIVE LATE WEDNESDAY LASTING INTO FRIDAY.
CONFIDENCE IS INCREASING WITH THIS STORM AS THERE REMAINS STRONG
SYNOPTIC AGREEMENT THROUGH THE EXTENDED PERIOD.

MONDAY...BRIEF SHORTWAVE RIDGING ALOFT WILL BREAK DOWN AND BUILD
EAST OF THE FORECAST AREA AS A SHORTWAVE TROUGH ADVANCED FROM THE
ROCKIES ACROSS THE PLAINS. LONGER RANGE SOLUTIONS CONTINUE TO SHOW
LIMITED SUPPORT FOR PRECIPITATION PRODUCTION...THUS WILL CONTINUE
THE DRY FORECAST FOR NOW. THE WAVE WILL PULL A COLD FRONT ACROSS
THE CWA LATE SUNDAY INTO EARLY MONDAY...WITH STRONG CAA AND A TIGHT
GRADIENT TO FOLLOW...MONDAY WILL BE BLUSTERY WITH HIGHS RUNNING 15F
OR MORE COOLER THAN SUNDAY AFTERNOON. INTO TUESDAY...THE OVERALL
SYNOPTIC PATTERN REMAINS FAIRLY PROGRESSIVE AS SHORTWAVE RIDGING
BUILDS ACROSS WESTERN NEBRASKA...HOWEVER TEMPERATURES WILL BE SLOW
TO WARM TUESDAY AND WEDNESDAY HOWEVER AS EASTERLY FLOW WILL RECYCLE
ARCTIC AIR BACK ACROSS MUCH OF THE CWA. SEEING A LARGE RANGE IN
HIGHS FOR BOTH MONDAY AND TUESDAY...WITH 20S ACROSS NORTH CENTRAL
NEBRASKA...AND POSSIBLY UPPER 30S TO LOW 40S ACROSS THE FAR
SOUTHWEST.

ATTENTION NOW TURNS TO THE POTENTIALLY BIG WINTER STORM FOR WEDNESDAY
NIGHT AND THURSDAY. LONG RANGE SOLUTIONS CONTINUE TO ADVERTISE A STRONG
UPPER LOW WHICH WILL EJECT FROM THE FOUR CORNERS REGION WEDNESDAY
NIGHT INTO THE CENTRAL PLAINS BY EARLY THURSDAY. CYCLOGENESIS WILL
BE ONGOING ACROSS THE EASTERN PLAINS OF COLORADO ON WEDNESDAY...WITH
A RAPID DEEPENING OF THE SURFACE LOW EXPECTED. GIVEN STRONG SURFACE
HIGH PRESSURE OF ~1040MB OVER THE GREAT LAKES REGION...AN INCREASING
PRESSURE GRADIENT WILL DEVELOP ACROSS THE CWA...WITH THE POTENTIAL OF
25-30 MPH WIND GUSTS WEDNESDAY AND THURSDAY. THE MODELS ALSO
SUGGEST PLENTIFUL MOISTURE ADVECTION IN ADVANCE OF THE SYSTEM...WITH
EASTERLY UPSLOPE POSSIBLY ALLOWING FOR SNOW PRODUCTION AS EARLY AS
LATE WEDNESDAY NIGHT. MEANWHILE...DOWNSTREAM OF THE UPPER
TROUGH...RIDGING AND PV DESTRUCTION ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY WILL ALLOW THE TROUGH/CLOSED LOW TO BECOME NEGATIVELY
TILTED...WITH THE PROGRESSION OF THE H5 LOW SLOWED. MODEL CONSENSUS
INDICATES THE TRACK OF THE H5 LOW FROM SE COLORADO INTO NEBRASKA
FROM 06Z THURSDAY THROUGH 00Z FRIDAY...PLACING MUCH OF THE FORECAST
AREA UNDER A BROAD DEFORMATION BAND FOR A 12-18 HOUR
PERIOD....THUS THE POTENTIAL OF A LONG SNOW EVENT IS POSSIBLE.
THERE ARE A FEW DIFFERENCES WITH THE TRACK OF THE H5 LOW...MAINLY
THE GFS AND ENSEMBLES ARE MORE PROGRESSIVE WITH THE TRACK OF THE
LOW...CARRYING IT INTO SOUTHEASTERN NEBRASKA BY 00Z FRIDAY. THE EC
WOBBLES THE H5 LOW NORTHWARD THROUGH CENTRAL NEBRASKA INTO SOUTH
DAKOTA BY 06Z FRIDAY. REGARDLESS OF THE DIFFERENCES...MEAN /GFS AND
EC/ QPF ACCUMULATION ARE CLOSE TO EACH OTHER /~.75 OF INCH AT
KLBF/...WITH THE ENSEMBLES RUNNING SLIGHTLY HIGHER /.85/...ALL OF
THIS IS EXPECTED TO FALL AS SNOW...POSSIBLY WIND DRIVEN. GIVEN THE
INGREDIENTS...A MAJOR WINTER STORM IS TAKING SHAPE.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1159 AM CST SAT FEB 16 2013

LIGHT SNOW SHOWERS OR FLURRIES WILL BE CONFINED TO LOCATIONS EAST
OF A LINE FROM KANW TO KBBW THIS AFTERNOON AND WILL DIMINISH BY
EVENING AS A WARM FRONT PROGRESSES ACROSS THE AREA INTO EASTERN
NEBRASKA. SKIES HAVE CLEARED OVER MUCH OF WESTERN NEBRASKA BY
18Z...HOWEVER WITH AFTERNOON MIXING...COULD SEE SOME SCATTERED
CLOUDS NEAR 7K FEET. ALSO WITH THE MIXING OF THE BOUNDARY LAYER
EXPECTED...SHOULD SEE NORTHWEST WINDS WITH GUSTS TO 25 OR 30KTS
THROUGH THE AFTERNOON HOURS. CLEAR SKIES ARE EXPECTED
OVERNIGHT...WITH WINDS DIMINISHING AS WELL. FOR SUNDAY...A COLD
FRONT WILL MAKE ITS WAY INTO THE CENTRAL AND NORTHERN PLAINS.
WINDS WILL SHIFT TO THE SOUTHWEST BY SUNDAY MORNING AHEAD OF THE
FRONT AND INCREASE BY 18Z. THE FRONT IS NOT EXPECTED TO MOVE
THROUGH KVTN OR KLBF UNTIL SUNDAY AFTERNOON OR EVENING SO A WIND
SHIFT WILL NOT COME THROUGH THIS TIME PERIOD. MAY SEE AN INCREASE
OF CLOUDS IN ADVANCE OF THE FRONT ON SUNDAY...BUT CEILINGS WILL BE
VFR.

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

UPDATE...BROOKS
SHORT TERM...JACOBS
LONG TERM...JACOBS
AVIATION...BROOKS

AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

642 AM CST SAT FEB 16 2013

.UPDATE...

.SHORT TERM...
MULTI MODEL BLEND OF RUC...HRRR...GEMREG...SREF...NAM...ECM
PRODUCED WARMER TEMPS TODAY AND SUNDAY AS WARRANTED BY THE KUNR
SOUNDING. NO DISCERNIBLE CHANGE OCCURRED TO THE ONGOING WEATHER
USING THE SAME BLEND. A NEW FCST IS OUT...KIML COULD REACH 60F ON
SUNDAY. OVERALL THE SNOW MOVES OUT QUICKLY THIS MORNING WITH
CLEARING TO FOLLOW JUST A RAPIDLY ALONG AND WEST OF HIGHWAY 83.
CLOUDS STAY IN LONGER EAST OF 83 AS ANOTHER BATCH OF CLOUDS MOVES
DOWN FROM THE DAKOTAS LATER THIS MORNING.

.PREV DISCUSSION... /ISSUED 515 AM CST SAT FEB 16 2013/

UPDATE...

AVIATION...
MVFR IN SNOW AND LOW CIGS WILL MOVE SLOWLY EAST TODAY. THE RUC AND
NAM KEEP MVFR CIGS IN PLACE FROM KVTN-KTIF EAST THROUGHOUT THE
AFTN EVEN AFTER THE SNOW ENDS WHILE THE GFS OPENS UP THE AREA TO
VFR BY 18Z ONCE THE SNOW MOVES OUT. THE FCST FOLLOWS THE GFS...THE FASTER
SOLNS. THE GENERAL FEELING IS ONCE THE SNOW ENDS...CIGS WILL
IMPROVE TO VFR.

VFR IS EXPECTED ALL AREAS TONIGHT IF THE GFS VERIFIES.

PREV DISCUSSION... /ISSUED 413 AM CST SAT FEB 16 2013/

UPDATE...

SHORT TERM...
RAN A BLEND OF ECM...GEMREG...NAM...RUC AND HRRR FOR THE ONGOING
LIGHT SNOW ASSOCIATED WITH THE WARM FRONT ACROSS WRN NEB. THIS
STILL GIVES LESS THAN AN INCH ACCUMULATION BUT THE RADAR IS
LOOKING PRETTY ROBUST SO WE WILL HAVE TO WAIT FOR THE SNOW TO PASS
OVER AN OBSERVATION SITE.

THE LATEST DETAILS ON THE WEDS-THUR STORM ARE OUT IN THE FORM OF A
SPECIAL WEATHER STATEMENT.

PREV DISCUSSION... /ISSUED 337 AM CST SAT FEB 16 2013/

AVIATION...
SHORT RANGE PROJECTIONS INDICATE LIGHT SNOW OR FLURRIES MOVING
INTO NORTH CENTRAL NEBRASKA BY 12Z AND ARE MOST LIKELY NORTH AND
EAST OF A VTN-BBW LINE. IN THAT AREA...CEILINGS ARE LIKELY TO BE
LESS THAN 1000 FEET AGL AND VISIBILITY LESS THAN 3SM. HOWEVER...AT
THIS TIME...IT APPEARS THAT VTN...TIF AND BBW WILL BE ON THE WESTERN
EDGE WITH CEILINGS 1000-2000 FEET AGL AND WE WILL KEEP THE
INSTRUMENT CONDITIONS OUT OF THE TERMINAL FORECAST FOR VTN FOR THE
TIME BEING.

IN THE REST OF CENTRAL AND WESTERN NEBRASKA...CEILINGS ARE LIKELY
TO BE ABOVE 3000 FEET AGL WITH NO RESTRICTIONS TO VISIBILITY.

WIND IS EXPECTED TO INCREASE SATURDAY MORNING AND BECOME 300-320
AT 10-14G20-24KT 18Z AND LATER. LOOKING AT THE SHORT TERM FORECAST
SOUNDINGS FOR LBF...I SEE THAT WIND INCREASES SHARPLY AT THE TOP
OF THE SURFACE INVERSION JUST ABOVE 2000 FEET AGL WITH SPEED
CHANGE OF ABOUT 30KT AND ABOUT 30 DEGREES CHANGE IN DIRECTION. AT
THIS TIME... IT APPEARS THAT THE SHEAR WILL BE HIGHER THAN THE
THRESHOLD ALTITUDE OF 2000 FEET AGL AND WILL NOT BE INCLUDED IN
THE TERMINAL FORECAST FOR LBF. THE TIME OF THE GREATEST RISK OF
LOW LEVEL WIND SHEAR WILL BE 12-15Z.

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

SHORT TERM...CDC
LONG TERM...CDC
AVIATION....CDC

AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

515 AM CST SAT FEB 16 2013

.UPDATE...

.AVIATION...
MVFR IN SNOW AND LOW CIGS WILL MOVE SLOWLY EAST TODAY. THE RUC AND
NAM KEEP MVFR CIGS IN PLACE FROM KVTN-KTIF EAST THROUGHOUT THE
AFTN EVEN AFTER THE SNOW ENDS WHILE THE GFS OPENS UP THE AREA TO
VFR BY 18Z ONCE THE SNOW MOVES OUT. THE FCST FOLLOWS THE GFS...THE FASTER
SOLNS. THE GENERAL FEELING IS ONCE THE SNOW ENDS...CIGS WILL
IMPROVE TO VFR.

VFR IS EXPECTED ALL AREAS TONIGHT IF THE GFS VERIFIES.

.PREV DISCUSSION... /ISSUED 413 AM CST SAT FEB 16 2013/

UPDATE...

THE LATEST DETAILS ON THE WEDS-THUR STORM ARE OUT IN THE FORM OF A
SPECIAL WEATHER STATEMENT.

PREV DISCUSSION... /ISSUED 337 AM CST SAT FEB 16 2013/

IN THE REST OF CENTRAL AND WESTERN NEBRASKA...CEILINGS ARE LIKELY
TO BE ABOVE 3000 FEET AGL WITH NO RESTRICTIONS TO VISIBILITY.

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

SHORT TERM...CDC
LONG TERM...CDC
AVIATION....CDC

AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

413 AM CST SAT FEB 16 2013

.UPDATE...

.SHORT TERM...
RAN A BLEND OF ECM...GEMREG...NAM...RUC AND HRRR FOR THE ONGOING
LIGHT SNOW ASSOCIATED WITH THE WARM FRONT ACROSS WRN NEB. THIS
STILL GIVES LESS THAN AN INCH ACCUMULATION BUT THE RADAR IS
LOOKING PRETTY ROBUST SO WE WILL HAVE TO WAIT FOR THE SNOW TO PASS
OVER AN OBSERVATION SITE.

THE LATEST DETAILS ON THE WEDS-THUR STORM ARE OUT IN THE FORM OF A
SPECIAL WEATHER STATEMENT.

.PREV DISCUSSION... /ISSUED 337 AM CST SAT FEB 16 2013/

IN THE REST OF CENTRAL AND WESTERN NEBRASKA...CEILINGS ARE LIKELY
TO BE ABOVE 3000 FEET AGL WITH NO RESTRICTIONS TO VISIBILITY.

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

SHORT TERM...CDC
LONG TERM...CDC
AVIATION....CDC

AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

203 AM CST SAT FEB 16 2013

.UPDATE...

.SHORT TERM...
THE GEMREG...NAM...RUC AND HRRR SHOW A DEVELOPING WARM FRONT
MOVING EAST THROUGH NRN NEB THIS MORNING AND WEAKENING DURING THE
AFTN. RADAR SUPPORTS THE DEVELOPMENT OF SCATTERED SNOW SHOWERS.
SKIES SHOULD CLEAR OUT BEHIND THE WARM FRONT THROUGHOUT THE
MORNING...AFTN AND EVENING HOURS. TEMPERATURES TODAY RANGE FROM
NEAR 40 NORTHEAST TO MID 50S SOUTHWEST. LOW THROUGHOUT THE FCST
AREA TONIGHT FALL TO AROUND 20.

.PREV DISCUSSION... /ISSUED 1134 PM CST FRI FEB 15 2013/

AVIATION...

SHORT RANGE PROJECTIONS INDICATE LIGHT SNOW OR FLURRIES MOVING
INTO NORTH CENTRAL NEBRASKA BY 12Z AND ARE MOST LIKELY NORTH AND
EAST OF A VTN-BBW LINE. IN THAT AREA...CEILINGS ARE LIKELY TO BE
LESS THAN 1000 FEET AGL AND VISIBILITY LESS THAN 3SM. HOWEVER...AT
THIS TIME...IT APPEARS THAT VTN...TIF AND BBW WILL BE ON THE WESTERN
EDGE WITH CEILINGS 1000-2000 FEET AGL AND WE WILL KEEP THE
INSTRUMENT CONDITIONS OUT OF THE TERMINAL FORECAST FOR VTN FOR THE
TIME BEING.

IN THE REST OF CENTRAL AND WESTERN NEBRASKA...CEILINGS ARE
LIKELY TO BE ABOVE 3000 FEET AGL WITH NO RESTRICTIONS TO
VISIBILITY.

WIND IS EXPECTED TO INCREASE SATURDAY MORNING AND BECOME 300-320
AT 10-14G20-24KT 18Z AND LATER. LOOKING AT THE SHORT TERM FORECAST
SOUNDINGS FOR LBF...I SEE THAT WIND INCREASES SHARPLY AT THE TOP OF
THE SURFACE INVERSION JUST ABOVE 2000 FEET AGL WITH SPEED CHANGE OF
ABOUT 30KT AND ABOUT 30 DEGREES CHANGE IN DIRECTION. AT THIS TIME...
IT APPEARS THAT THE SHEAR WILL BE HIGHER THAN THE THRESHOLD ALTITUDE
OF 2000 FEET AGL AND WILL NOT BE INCLUDED IN THE TERMINAL FORECAST
FOR LBF. THE TIME OF THE GREATEST RISK OF LOW LEVEL WIND SHEAR WILL
BE 12-15Z.

PREV DISCUSSION... /ISSUED 337 PM CST FRI FEB 15 2013/

SYNOPSIS...
ISSUED AT 335 PM CST FRI FEB 15 2013

AT 21Z...WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH MOVING
THROUGH THE DAKOTAS AND CENTRAL NEBRASKA EMBEDDED WITHIN A TROUGH
CENTERED NORTH TO SOUTH THROUGH THE MISSISSIPPI RIVER VALLEY.
UPSTREAM...A STRONG RIDGE WAS IN PLACE ACROSS THE WEST
COAST...WITH A SHORTWAVE TROUGH MOVING TOWARDS BRITISH COLUMBIA.
LOCALLY...CONVECTIVE SNOW SHOWERS WERE SEEN ACROSS MUCH OF
NEBRASKA AS STEEP LOW LEVEL LAPSE RATES AND MIXING WAS OBSERVED.

SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 335 PM CST FRI FEB 15 2013

SHOWER ACTIVITY WILL DIMINISH THIS EVENING WITH THE LOSS OF
DAYTIME HEATING. CLOUD COVER WILL ALSO DIMINISH FOR A TIME DURING
THE EVENING HOURS AS THE FORECAST AREA SITS IN AN AREA OF
SUBISIDENCE ON THE BACKSIDE OF THE SHORTWAVE TROUGH.

A WARM FRONT WILL MOVE EAST ACROSS NEBRASKA OVERNIGHT...SO
EXPECTING LOWS EARLY /AROUND 06Z/. WARM ADVECTION ALOFT...ALONG
WITH SOME DECENT CONVERGENT AND LIFT ALONG THE FRONT COULD BRING
MORE LIGHT SNOW BEGINNING AFTER 09Z. PUT SOME FLURRIES IN THE
FORECAST FOR LOCATIONS ACROSS NORTHERN NEBRASKA NEAR HIGHWAY 83.
GOING INTO SATURDAY MORNING...AS THE FRONT TRANSITIONS EAST...THE
SNOW CHANCES WILL ALSO MOVE EAST INTO NORTH CENTRAL NEBRASKA.
DON/T BELIEVE ANY AMOUNTS WILL BE MUCH...MAYBE A TENTH OF AN INCH
OR SO...BUT DID ADD SNOW CHANCES EAST OF HIGHWAY 83 AND NORTH OF
HIGHWAY 91. BEHIND THE FRONT...MUCH WARMER AIR WILL MOVE INTO THE
AREA. BY 00Z SUNDAY...850MB TEMPERATURES WILL RISE 10 DEGREES OR
BETTER...WITH VALUES AROUND 5C OVER THE FAR SOUTHWEST COUNTIES.
THIS WARMING WILL LEAD TO HIGHS IN THE 40S AND EVEN LOW 50S ACROSS
THE FORECAST AREA. SNOW COVER DOES REMAIN FROM LAST WEEK/S SNOW
STORM...SO WILL LIKELY SEE AN AREA WITH COOLER HIGHS FROM THE EAST
CENTRAL PANHANDLE UP THROUGH NORTH CENTRAL NEBRASKA. SOME OF THESE
PLACES MAY ONLY SEE HIGHS UP IN THE UPPER 30S TO AROUND 40.

LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 PM CST FRI FEB 15 2013

A WARM FRONT WILL MOVE TO THE EAST ACROSS THE FORECAST AREA WITH
WARM DRY PACIFIC AIR AS THE RIDGE OVER THE WESTERN CONUS PUSHES
EAST. STILL SOME SNOW COVER OVER THE SANDHILLS BUT SATURDAYS HIGHS
EXPECTED TO CUT IT BACK SIGNIFICANTLY. HIGH TEMPERATURES SUNDAY
AROUND 50 SOUTH AND MID 40S NORTH. 850MB TEMPERATURES AROUND 9C
SUNDAY. LOW PRESSURE WILL MOVE ALONG THE CANADIAN BORDER AND DRAW
A COLD FRONT THROUGH THE NORTHERN PLAINS SUNDAY NIGHT INTO MONDAY
WITH STRONG COLD AIR ADVECTION...GUSTY NORTHWEST WINDS AND
POSSIBLY SOME LIGHT SNOW. HAVE LEFT DRY FOR NOW WITH BUFR
SOUNDINGS SHOWING HIGH BASED PRECIP VIRGA WITH MUCH DRIER LOWER
LEVELS. COLD ARCTIC AIR WILL MOVE SOUTH INTO THE CENTRAL PLAINS
THROUGH THE MIDDLE OF THE WEEK WITH HIGHS IN THE 30S MONDAY
FALLING INTO THE TEENS AND 20S FOR HIGHS ON THURSDAY FRIDAY.
TRAJECTORY OF STORM SYSTEM MOVING OUT OF THE ROCKIES AND ONTO THE
PLAINS WEDNESDAY WILL HAVE ABUNDANT MOISTURE FROM A WIDE OPEN
GULF. TRAJECTORY FURTHER WEST THAN USUAL WITH MOISTURE ADVECTING
ACROSS THE SOUTHERN PLAINS THROUGH THE TEXAS PANHANDLE INTO
NORTHEAST COLORADO FROM WEDNESDAY. STRONG DEEP EASTERLY FLOW OVER
WESTERN NEBRASKA WEDNESDAY INTO THURSDAY. HAVE UPPED POPS INTO
LIKELY CATEGORIES ON THURSDAY. REMAINS TO BE SEEN HOW MUCH
CONVECTION WILL BE OVER THE CENTRAL AND SOUTHERN PLAINS WHICH MAY
ROB NEEDED MOISTURE. MODELS CONTINUE IN GOOD AGREEMENT WITH THIS
SYSTEM. COOL DOWN TOWARDS THE END OF THE WEEK AND THEN GRADUALLY
WARMING INTO THE WEEKEND BUT REMAINING WELL BELOW NORMAL FOR THE
SEASON. MORE ACTIVE PATTERN.

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

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION....CDC

AREA FORECAST DISCUSSION

NWS BUFFALO NY

1032 AM EST SAT FEB 16 2013

.SYNOPSIS...
A COLD ARCTIC AIRMASS WILL FILTER INTO THE REGION TODAY WITH SOME
SCATTERED LIGHT LAKE EFFECT SNOWS SOUTH OF THE LAKES. THE COLDEST
AIR WILL ARRIVE ACROSS THE REGION SUNDAY AS A STRONG STORM SYSTEM
MOVES ALONG THE NEW ENGLAND COAST. TEMPERATURES WILL ONLY RISE INTO
THE TEENS SUNDAY. MONDAY A MODEST WARMING TREND BEGINS AHEAD OF THE
NEXT STORM TO IMPACT THE AREA WITH A WINTRY MIX MONDAY NIGHT.

.NEAR TERM /THROUGH TONIGHT/...
THROUGH MID-MORNING...A WEAK AREA OF HIGH PRESSURE EXTENDS
ACROSS EASTERN LAKE ONTARIO...WITH AN UPPER LEVEL TROF AXIS TO THE
WEST ACROSS MICHIGAN. THERE ARE A COUPLE OF ILL-DEFINED FRONTAL
BOUNDARIES IN THE MIX. A CONVERGENT FLOW ON LAKE ONTARIO CAN ALSO
BE SEEN...PROBABLY DUE TO A LEFT OVER FRONTAL BOUNDARY...OR LAKE
CONVERGENCE DUE TO THE LOCALLY WARMER TEMPERATURES.

RADAR TREND SHOW AN EXPANSION OF SNOW SHOWERS ACROSS LAKE
ERIE...WITH CONTINUED SNOW SHOWERS ON THE OPEN WATERS OF LAKE
ONTARIO. WHILE THE LATTER IS FORECAST TO REMAIN OUT ON THE
WATERS...THE APPROACHING UPPER TROF IS LIKELY TO PUSH THE SNOW
SHOWERS ON LAKE ERIE ONSHORE. A CONSENSUS OF THE 12Z NAM/00Z
RGEM/12Z HRRR ALL SHOW SOME LIGHT QPFS ASSOCIATED WITH THIS DURING
THE AFTERNOON HOURS. BASED ON THE UPPER PATTERN...WHICH WILL SHIFT
BOUNDARY LAYER WINDS TO THE WEST...THESE SOLUTIONS MAKE SENSE.
BECAUSE OF THIS...WILL UP POPS TO LIKELY WEST OF ROCHESTER THIS
AFTERNOON. THIS SAID...BECAUSE OF THE TRANSIENT NATURE OF THIS
FEATURE...EXPECT ONLY LIGHT ACCUMULATIONS. WINDS WILL BE TOO
SHEARED FOR MUCH IN THE WAY OF ORGANIZED BANDS. THERE IS SOME
INDICATION BY THE HRRR THAT BRIEF PERIOD OF MODERATE SNOW SHOWERS
WILL DEVELOP...BUT ITS HARD TO SAY WHERE THESE WOULD OCCUR GIVEN
VARIABILITY IN MODEL RUNS. THE FAST MAJORITY OF LOCATIONS WILL GET
LESS THAN AN INCH...WITH AN INCH OR TWO POSSIBLE IN HEAVIER SNOW
SHOWERS. DO EXPECT A GOOD FLUFF FACTOR GIVEN 850 MB TEMPS OF -16C
AS SHOWN ON OUR MORNING SOUNDING.

EAST OF LAKE ONTARIO SHOULD REMAIN DRY...WITH A FAIR AMOUNT OF
SUNSHINE. EXPECT HIGHS IN THE LOWER TO MID 20S IN MOST LOCATIONS.

TONIGHT...THE WEAK SURFACE LOW WILL BE ABSORBED INTO THE
STRENGTHENING STORM SYSTEM TRACKING NORTH OFF THE EAST COAST. AS
THIS OCCURS MUCH COLDER AIR WILL ARRIVE UNDER NORTHWEST WINDS. THE
CORE OF THE UPPER LEVEL TROUGH...COLD POOL ALOFT...WILL SHIFT OVER
WESTERN NY. TEMPERATURES WILL PLUMMET THROUGH THE TEENS INTO THE
SINGLE DIGITS MAKING FOR A VERY COLD NIGHT. WINDS WILL BE FAIRLY
LIGHT SO NO THREAT FOR MUCH OF AN IMPACT FROM WIND CHILLS. THE NAM
AND RGEM MODELS SHOW THAT SOME LAKE LAKE EFFECT COULD BECOME
ORGANIZED EAST OF LAKE ERIE WITH NORTHWEST WINDS ALIGNING AND 850 MB
TEMPS DROPPING TO AROUND -18C. ACCUMULATIONS ACROSS THE SOUTHERN TIER
COULD BE IN THE TWO TO THREE INCH RANGE. ORGANIZED ACTIVITY OFF LAKE
ONTARIO WILL HOLD OFF UNTIL SUNDAY.

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A WELL ALIGNED NORTHWEST OF COLDER AIR WILL SET UP ACROSS THE LOWER
LAKES ON SUNDAY IN THE WAKE OF THE DEEP UPPER LEVEL TROUGH THAT WILL
SLIDE EAST INTO NEW ENGLAND. WHILE THE DEEPER SYNOPTIC SCALE
MOISTURE WILL SHIFT EAST INTO NEW ENGLAND...ENOUGH LOW LEVEL
MOISTURE WILL REMAIN WITHIN WITH THE LAYER OF FAVORABLE SNOW GROWTH.
THIS WILL RESULT IN BETTER ORGANIZED LAKE EFFECT SNOW SOUTHEAST OF
BOTH LAKES. IT STILL LOOKS LIKE SNOW ACCUMULATIONS WILL STAY BELOW
ADVISORY CRITERIA DUE TO THE SHORT FETCH ACROSS THE LAKES AND THE
UNCERTAINTY REGARDING CONTRIBUTIONS OF MOISTURE FROM UPSTREAM LAKES.
EXPECT THE HIGHEST ACCUMULATIONS TO BE ALONG THE CHAUTAUQUA RIDGE
AND SOUTHEAST OF LAKE ONTARIO...FROM WAYNE TO SOUTHERN OSWEGO
COUNTIES. AREAS OUTSIDE OF THE STEADIER LAKE EFFECT SNOW WILL SEE
PARTLY CLOUDY SKIES WITH SOME FLURRIES. IT WILL BE RATHER COLD WITH
AREAS TEMPERATURES EXPECTED TO HOLD STEADY IN THE TEENS.

THE ONGOING LAKE SNOWS WILL DIMINISH SUNDAY NIGHT AS THE LOW LEVEL
MOISTURE DECREASES AND THE SUBSIDENCE INVERSION CONTINUES TO LOWER.
THIS WILL HAPPEN FIRST OFF LAKE ERIE...BUT THE WEAKENING LAKE
ONTARIO BANDS WILL PROBABLY REMAIN INTACT THROUGH MONDAY MORNING.

ON MONDAY...A WEAK SURFACE RIDGE WILL BE SANDWICHED BETWEEN LOW
PRESSURE OVER THE CANADIAN MARITIMES AND A SECOND LOW THAT WILL BE
ADVANCING EAST INTO THE UPPER MIDWEST. THE SOUTHERLY FLOW THAT SETS
UP BETWEEN THESE TWO SYSTEMS WILL ALLOW TEMPERATURES TO REBOUND TO
NEAR SEASONAL LEVELS...AFTER A COLD START TO THE DAY. ANY LAKE
EFFECT SNOW SHOWERS THAT LINGER SOUTHEAST OF LAKE ONTARIO SHOULD END
BY EARLY AFTERNOON.

AS THE UPPER MIDWEST LOW TRACKS EAST ACROSS THE CENTRAL GREAT LAKES
SUNDAY NIGHT...A POTENT LOW LEVEL JET WILL BE HEADING NORTHEAST
TOWARD THE LOWER GREAT LAKES. THE LOW LEVEL JET WILL TAP INTO DEEPER
MOISTURE OVER THE LOWER OHIO AND TENNESSEE VALLEYS AND ALLOW PCPN TO
SPREAD EAST ACROSS OUR CWA. STRONG WARM AIR ADVECTION ALOFT ON THE
NOSE OF THE LOW LEVEL JET WILL CREATE A TEMPERATURE PROFILE THAT
WILL SUPPORT A WINTRY MIX OF PRECIPITATION...INCLUDING THE
POSSIBILITY OF SLEET AND FREEZING RAIN. THE LATEST GUIDANCE
SUGGESTS THAT THE CORE OF THE LOW LEVEL JET AND WARMEST TEMPERATURES
ALOFT WILL SHIFT EAST INTO CENTRAL AND EASTERN NEW YORK DURING THE
SECOND HALF OF THE NIGHT. AS A RESULT...THE RISK FOR FREEZING RAIN
MAY BE GREATER ACROSS THESE AREAS.

EXPECT TEMPERATURES TO HOLD STEADY OR SLOWLY RISE MONDAY NIGHT.

.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE CENTRAL GREAT LAKES LOW WILL SHIFT EAST ACROSS SOUTHERN ONTARIO
AND SOUTHERN QUEBEC ON TUESDAY. A PAIR OF FRONTS TRAILING SOUTH OF
THE LOW WILL HAVE SOME IMPACT ON THE CWA. MIXED PCPN AT THE START OF
THE DAY MAY CHANGE TO RAIN DURING THE MORNING...BEFORE COLDER AIR
BUILDS IN DURING THE AFTERNOON AND CHANGES THE PCPN BACK TO SNOW.
AS THE COLDER AIR DEEPENS TUESDAY NIGHT...WIDESPREAD SNOW SHOWERS
WILL CONTINUE.

AS FOR ANY WIND POTENTIAL...THERE IS A LOW LEVEL JET FORECAST TO
MOVE INTO THE REGION...NEAR 60-70KTS. GFS BUFKIT MOMENTUM TRANSFER
INDICATES A SUB-WARNING RESPONSE AS THE COLD AIR WORKS ITS WAY INTO
WESTERN NY. THIS MAKES SENSE AS THE SURFACE LOW SHOULD BE NO LONGER
DEEPENING AS IT MOVES WELL TO THE NORTH...WITH A ONLY A SMALL
ISALLOBARIC WIND RESPONSE AS THE MAIN PRESSURE CHANGES WILL BE WELL
NORTH OF THE REGION.

ONCE THIS SYSTEM MOVES OUT OF THE REGION...EXPECT SCATTERED SNOW
SHOWERS AND POSSIBLE STEADIER LAKE EFFECT SNOW TO CONTINUE INTO
WEDNESDAY.

ANOTHER RIDGE MOVES PAST ON THURSDAY FOR DRY WEATHER.

THE NEXT SYSTEM ALSO APPEARS TO BE FAIRLY WELL HANDLED BY VARIOUS
GUIDANCE PACKAGES. THIS SYSTEM CAN CURRENTLY BE FOUND HEADING
EAST...JUST SOUTH OF THE ALEUTIAN ISLANDS ON SATELLITE IMAGERY.
MODELS TAKE THIS FEATURE AND CREATE A CUTOFF OVER THE DESERT
SOUTHWEST...AND THEN ACROSS THE PLAINS AND INTO THE GREAT LAKES
REGION ON FRIDAY. CUTOFFS ARE NOT WELL HANDLED BY MODELS...AND
OFTEN SLOWER MOVE EAST THAN MODEL FORECASTS. WILL FORECAST A CHANCE
OF PRECIPITATION WITH THIS FEATURE AS IT IS SEVEN DAYS OUT...BUT IT
MIGHT END UP REMAINING DRY FOR FRIDAY.

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
THROUGH THE REMAINDER OF THE MORNING...EXPECT VFR CONDITIONS WITH
SCT-BKN CIGS ABOVE 3000 FEET. AFTER THIS...AN AREA OF SNOW SHOWERS
DEVELOPING ON EASTERN PORTIONS OF LAKE ERIE WILL GRADUALLY PUSH
EAST AND HAVE SOME IMPACT ON THE BUF/IAG/JHW/ROC TERMINALS. ANY
IMPACT SHOULD BE TEMPORARY IN NATURE...PROBABLY 1 TO 3 HOURS...BUT
DURING THIS TIME VSBY BELOW 2SM IS POSSIBLE. ART SHOULD REMAIN DRY
AND VFR.

THIS AREA WILL DISSIPATE THIS EVENING...BUT UPSLOPE SNOW SHOWERS
SHOULD EXPAND LATE TONIGHT...RESULTING IN LOWERING CIGS/VSBY SOUTH
OF LAKE ONTARIO. SNOWFALL RATES SHOULD GENERALLY BE ON THE LIGHT
SIDE AT MOST TAF LOCATIONS THROUGH 12Z.

OUTLOOK...
SUNDAY THROUGH SUNDAY NIGHT...VFR/MVFR WITH SCATTERED SNOW SHOWERS.
MONDAY...VFR.
TUESDAY...MVFR/IFR...RAIN CHANGING OVER TO SNOW LATE.
TUESDAY NIGHT THROUGH WEDNESDAY...MVFR/LOCALIZED IFR IN LAKE EFFECT
SNOW SHOWERS.

.MARINE...
A COLD FRONT WILL STALL OVER THE SOUTHERN SHORE OF LAKE ONTARIO
TODAY AS A WEAK SURFACE LOW TRACKS EAST ALONG THE BOUNDARY. THIS
WILL WILL RESULT IN LIGHT AND VARIABLE WINDS THROUGH MUCH OF TODAY.
NORTHWESTERLY WINDS WILL INCREASE SUNDAY AS COASTAL STORM SYSTEM
MOVES EAST OF NEW ENGLAND. THIS WILL LIKELY BRING ANOTHER ROUND OF
SMALL CRAFT ADVISORIES ALONG THE SOUTHERN LAKE ONTARIO SHORELINE.

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

SYNOPSIS...SMITH
NEAR TERM...APFFEL/SMITH
SHORT TERM...TJP
LONG TERM...TJP/ZAFF
AVIATION...APFFEL/SMITH
MARINE...APFFEL/SMITH

AREA FORECAST DISCUSSION

NWS BUFFALO NY

953 AM EST SAT FEB 16 2013

EAST OF LAKE ONTARIO SHOULD REMAIN DRY...WITH A FAIR AMOUNT OF
SUNSHINE. EXPECT HIGHS IN THE LOWER TO MID 20S IN MOST LOCATIONS.

EXPECT TEMPERATURES TO HOLD STEADY OR SLOWLY RISE MONDAY NIGHT.

ONCE THIS SYSTEM MOVES OUT OF THE REGION...EXPECT SCATTERED SNOW
SHOWERS AND POSSIBLE STEADIER LAKE EFFECT SNOW TO CONTINUE INTO
WEDNESDAY.

ANOTHER RIDGE MOVES PAST ON THURSDAY FOR DRY WEATHER.

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
SCT/BKN VFR CIGS PRESENT AT 12Z ACROSS THE AREA WITH SCATTERED LIGHT
SNOW SHOWERS ACROSS WESTERN NY. A WEAK LOW PRESSURE AREA ARRIVING
FROM NEAR GEORGIAN BAY WILL CONTINUE TO BRING SCATTERED SNOW SHOWERS
ALONG WITH LIGHT AND VARIABLE WINS TROUGH MUCH OF TODAY AND INTO
TONIGHT. THE WEAK LOW WILL BE ABSORBED BY A COASTAL STORM TONIGHT
AND A MORE ALIGNED NORTHWEST FLOW WILL DEVELOP WITH ORGANIZED LAKE
SNOWS RETURNING SOUTHEAST OF THE LAKES SUNDAY MORNING.

.MARINE...
A COLD FRONT WILL STALL OVER THE SOUTHERN SHORE OF LAKE ONTARIO
TODAY AS A WEAK SURFACE LOW TRACKS EAST ALONG THE BOUNDARY. THIS
WILL WILL RESULT IN WINDS WILL BECOMING LIGHT AND VARIABLE THROUGH
MUCH OF TODAY. WILL CONTINUE SCA FOR THE SOUTHERN AND SOUTHEASTERN
LAKE ONTARIO NEAR SHORES THROUGH MID MORNING WITH HIGHER WAVES
LINGERING AFTER WINDS SUBSIDE. NORTHWESTERLY WINDS WILL INCREASE
SUNDAY AS COASTAL STORM SYSTEM MOVES EAST OF NEW ENGLAND. THIS WILL
LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES ALONG THE
SOUTHERN LAKE ONTARIO SHORELINE.

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

SYNOPSIS...SMITH
NEAR TERM...APFFEL/SMITH
SHORT TERM...TJP
LONG TERM...TJP/ZAFF
AVIATION...SMITH
MARINE...APFFEL/SMITH

AREA FORECAST DISCUSSION

NWS RALEIGH NC

948 AM EST SAT FEB 16 2013

.SYNOPSIS...
A STRONG TROUGH ALOFT WILL PIVOT ACROSS THE SOUTHEASTERN US
TODAY...AND RESULT IN RAPID CYCLOGENESIS UP THE MIDDLE ATLANTIC
AND NORTHEAST COASTS TONIGHT AND SUNDAY.

.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM SATURDAY...

UPDATE:

REAL QUICK UPDATE TO INCLUDE EXPANSION OF WINTER WX ADVISORY FOR
MOST OF CENTRAL NC...THAT NOW EXTENDS ALONG AND EAST OF A LINE FROM
ALBEMARLE...TO ASHEBORO...TO GREENSBORO.

ANOTHER UPDATE WILL BE ISSUED SHORTLY.

ALTHOUGH IT APPEARS THAT THE SURFACE CYCLONE WILL BE DEVELOPING
CLOSER TO THE COAST (NEAR MHX) THAN PREVIOUSLY ANTICIPATED AND
THAT RELATIVELY MORE PRECIP WILL OCCUR ACROSS CENTRAL NC (PER
LATEST RAP MODEL RUNS) IN ASSOC/W STRONG LOW-LEVEL FRONTOGENESIS
12-18Z AND THEN STRONG DPVA IN THE PRESENCE OF A DESTABILIZING
AIRMASS 21-00Z...IT APPEARS THAT THE BOUNDARY LAYER WILL REMAIN
TOO WARM THROUGH ~00Z THIS EVENING FOR A CHANGEOVER TO OCCUR IN
MOST LOCATIONS...WITH THE COLDER AIRMASS CURRENTLY BUILDING INTO
THE MID-ATLANTIC STALLING NORTH OF CENTRAL NC DUE TO VERY STRONG
H5 HEIGHT FALLS IN ADVANCE OF THE APPROACHING UPPER LEVEL
TROUGH...RESULTING IN BROAD PRESSURE FALLS OVER NC/VA WHICH WILL
HOLD A WEAK PRESSURE TROUGH IN PLACE AND DELAY THE ARRIVAL OF THE
COLDER AIRMASS FROM THE NORTH. EXPECT THE BEST CHANGEOVER
POTENTIAL TO OCCUR AFTER 00Z...WHEN FORCING FOR PRECIP WILL
GENERALLY BEGIN TO WANE OVER CENTRAL NC AND PRECIPITATION WILL
BEGIN TO PROGRESS EAST TOWARD THE COAST.

BASICALLY...THIS MAY BE YET ANOTHER CASE WHERE THE COLD AIR `CHASES`
THE PRECIP...EXCEPT PERHAPS N/NE OF THE TRIANGLE WHERE FAVORABLE
THERMAL PROFILES ARE MORE LIKELY TO COINCIDE WITH STRONG FORCING IN
THE FORM OF LOW-LEVEL FRONTOGENESIS AND STRONG DPVA IN THE PRESENCE
OF VERY STEEP (7-8C/KM) MID-LEVEL LAPSE RATES. ONE CAVEAT...GIVEN
STRONG DPVA...GOOD LOW-LEVEL FRONTOGENESIS AND VERY STEEP MID-LEVEL
LAPSE RATES (7-8 C/KM) IN ADVANCE OF THE APPROACHING UPPER LEVEL
TROUGH...IT IS POSSIBLE THAT A QUICK BURST OF ACCUMULATING
CONVECTIVE SNOW COULD OCCUR AT ABOUT THE SAME TIME AS THE COLDER
AIRMASS BEGINS TO ARRIVE FROM THE NORTH ~00Z FROM GUILFORD/RANDOLPH
COUNTIES EASTWARD. HOWEVER...PREVIOUS EXPERIENCE WOULD SUGGEST THAT
TOO MUCH UNCERTAINTY IS PRESENT TO WARRANT EXPANDING THE ADVISORY
AREA WHEN WAITING FOR A COLDER AIRMASS TO ADVECT INTO THE AREA AND
WHEN RELYING PRIMARILY ON CONVECTIVE PRECIPITATION FOR
ACCUMULATIONS. -VINCENT

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 210 AM SATURDAY...

BREEZY COLD CONDITIONS EARLY SUNDAY WILL PERSIST MUCH OF THE DAY.
LOW LEVEL THICKNESSES SUGGEST THE COLDEST AIR WILL BE OVER THE
NORTHERN AND EASTERN ZONES WHERE HIGHS WILL STRUGGLE TO REACH NEAR
40. TEMPERATURES IN THE 40S EXPECTED ACROSS THE SOUTHERN TIER NEAR
THE SC BORDER. THE COLD UPPER TROUGH IS FORECAST TO BEGIN TO LIFT
OUT LATE SUNDAY INTO MONDAY. HOWEVER... THE COLD SURFACE HIGH
PRESSURE IS FORECAST TO BE DIRECTLY OVERHEAD SUNDAY NIGHT INTO 12Z
MONDAY. THIS WILL MEAN COLD/CLEAR/CALM CONDITIONS WITH HEAVY FROST
AND HARD FREEZE BY 12Z MONDAY. LOWS 18-25. WAA WILL BEGIN MONDAY...
ESPECIALLY IN THE AFTERNOON. OTHER THAN A FEW HIGH CLOUDS... IT
SHOULD BE MOSTLY SUNNY WITH SW WINDS 10-15 MPH. HIGHS 48 TO 55 NE TO
SW.

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 210 AM SATURDAY...

A COUPLE OF SYSTEMS ARE EXPECTED TO BRING RAIN CHANCES TO OUR REGION
THIS WEEK. THE FIRST IS FORECAST FOR TUESDAY. STRONG WARMING OUT
AHEAD OF THE COLD FRONT WILL LEAD TO ALL RAIN SHOWERS. A BIT OF
IN-SITU CAD MAY KEEP TEMPS DOWN IN THE PIEDMONT. QPF CONTINUES TO BE
LIGHT WITH UP TO 0.25 IN THE NW WITH LESSER AMOUNTS TO THE EAST.
CLOUDY WITH A 40-50 PERCENT CHANCE OF SHOWERS. HIGHS GENERALLY IN
THE 45-50 RANGE NW... WITH 50S SE AFTER LOWS OF 35-42 TUESDAY.

WEDNESDAY AND THURSDAY... HIGH PRESSURE SHOULD BUILD IN FROM THE NW
AND NORTH WED-THU... WITH THE STRONGEST CAA EXPECTED THU. THIS MAY
SET UP A STRONGER CAD EVENT FOR FRIDAY AS THE HIGH IS FORECAST TO BE
IN A FAVORABLE POSITION AND STRENGTH TO INDUCE CAD AS THE NEXT
SYSTEM APPROACHES FRIDAY.

WED...FAIR AND SEASONABLE. LOWS IN THE 30S. HIGHS IN THE 50S. THU...
MOSTLY SUNNY. LOWS 25-30. HIGHS 48-53. FRI..MOSTLY CLOUDY. A CHANCE
OF RAIN. CHILLY. LOWS IN THE 30S. HIGHS IN THE 40S EXCEPT 50-55 SE.

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 635 AM SATURDAY...

AFTER INITIALLY VFR CONDITIONS...THE PASSAGE OF A STRONG DEEP LAYER
FRONTAL ZONE WILL RESULT IN A RAPIDLY EXPANDING...BUT NARROW...
PRECIPITATION AXIS ACROSS THE WEST-CENTRAL CAROLINAS BETWEEN 12-15Z.
THE PRECIPITATION AXIS WILL THEN EXPAND IN AREAL EXTENT AND PIVOT
EASTWARD ACROSS CENTRAL NC THROUGH THIS EVENING...OWING TO THE
AMPLIFICATION OF A STRONG TROUGH ALOFT FROM THE CENTRAL PLAINS TO
THE SOUTHEAST STATES. THE PRECIPITATION WILL LIKELY BEGIN AS A MIX
OF RAIN AND SNOW...BEFORE GRADUALLY TRANSITIONING TO ALL SNOW FOR
THE AFTERNOON AND EVENING HOURS. CEILINGS AND VISIBILITY
RESTRICTIONS WILL CONSEQUENTLY FALL INTO MVFR-IFR RANGE...BEFORE THE
STEADY PRECIPITATION ENDS AND SKIES CLEAR FROM WEST TO EAST THIS
EVENING. A FEW LINGERING SNOW SHOWERS WILL BE POSSIBLE THROUGH
MIDNIGHT...HOWEVER...AS THE VERY COLD AND DYNAMIC TROUGH AXIS ALOFT
PIVOTS EASTWARD.

LOOKING AHEAD: BREEZY CONDITIONS SUNDAY...FOLLOWED BY ANOTHER
FRONTAL SYSTEM AND ASSOCIATED SUB-VFR CONDITIONS AND RAIN THAT WILL
AFFECT THE REGION TUE.

.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 4 AM EST
SUNDAY FOR NCZ011-027-028-042-043-078-088-089.
WINTER WEATHER ADVISORY UNTIL 4 AM EST SUNDAY FOR NCZ007>010-
022>026-039>041-073>077-083>086.

$$
SYNOPSIS...MWS
NEAR TERM...CBL/VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...MWS/BADGETT

AREA FORECAST DISCUSSION

NWS RALEIGH NC

635 AM EST SAT FEB 16 2013

.SYNOPSIS...
A STRONG TROUGH ALOFT WILL PIVOT ACROSS THE SOUTHEASTERN US
TODAY...AND RESULT IN RAPID CYCLOGENESIS UP THE MIDDLE ATLANTIC
AND NORTHEAST COASTS TONIGHT AND SUNDAY.

.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 AM SATURDAY...

...PERIOD OF WINTRY WEATHER REMAINS POSSIBLE THIS EVENING INTO
TONIGHT ALONG AND EAST OF HIGHWAY 1...

WILL LEAVE THE CURRENT ADVISORY AS-IS. EXPECT ACCUMULATIONS 1-2" AT
MOST...AND THOSE AMOUNTS ARE MOST LIKELY IN THE NE COASTAL PLAIN
NEAR THE VA BORDER N/NE OF THE TRIANGLE. ALTHOUGH IT APPEARS THAT
THE SURFACE CYCLONE WILL BE DEVELOPING CLOSER TO THE COAST (NEAR
MHX) THAN PREVIOUSLY ANTICIPATED AND THAT RELATIVELY MORE PRECIP
WILL OCCUR ACROSS CENTRAL NC (PER LATEST RAP MODEL RUNS) IN ASSOC/W
STRONG LOW-LEVEL FRONTOGENESIS 12-18Z AND THEN STRONG DPVA IN THE
PRESENCE OF A DESTABILIZING AIRMASS 21-00Z...IT APPEARS THAT THE
BOUNDARY LAYER WILL REMAIN TOO WARM THROUGH ~00Z THIS EVENING FOR A
CHANGEOVER TO OCCUR IN MOST LOCATIONS...WITH THE COLDER AIRMASS
CURRENTLY BUILDING INTO THE MID-ATLANTIC STALLING NORTH OF CENTRAL
NC DUE TO VERY STRONG H5 HEIGHT FALLS IN ADVANCE OF THE APPROACHING
UPPER LEVEL TROUGH...RESULTING IN BROAD PRESSURE FALLS OVER NC/VA
WHICH WILL HOLD A WEAK PRESSURE TROUGH IN PLACE AND DELAY THE
ARRIVAL OF THE COLDER AIRMASS FROM THE NORTH. EXPECT THE BEST
CHANGEOVER POTENTIAL TO OCCUR AFTER 00Z...WHEN FORCING FOR PRECIP
WILL GENERALLY BEGIN TO WANE OVER CENTRAL NC AND PRECIPITATION WILL
BEGIN TO PROGRESS EAST TOWARD THE COAST.

.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 210 AM SATURDAY...

.LONG TERM / MONDAY NIGHT THROUGH FRIDAY/...
AS OF 210 AM SATURDAY...

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 635 AM SATURDAY...

LOOKING AHEAD: BREEZY CONDITIONS SUNDAY...FOLLOWED BY ANOTHER
FRONTAL SYSTEM AND ASSOCIATED SUB-VFR CONDITIONS AND RAIN THAT WILL
AFFECT THE REGION TUE.

RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 PM SATURDAY TO 4 AM EST SUNDAY FOR
NCZ007>011-025>028-041>043-077-078-085-086-088-089.

SYNOPSIS...MWS
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...MWS/PWB

AREA FORECAST DISCUSSION

NWS RALEIGH NC

354 AM EST SAT FEB 16 2013

.SYNOPSIS...
A STRONG TROUGH ALOFT WILL PIVOT ACROSS THE SOUTHEASTERN US
TODAY...AND RESULT IN RAPID CYCLOGENESIS UP THE MIDDLE ATLANTIC
AND NORTHEAST COASTS TONIGHT AND SUNDAY.

.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 AM SATURDAY...

...PERIOD OF WINTRY WEATHER REMAINS POSSIBLE THIS EVENING INTO
TONIGHT ALONG AND EAST OF HIGHWAY 1...

.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 210 AM SATURDAY...

.LONG TERM / MONDAY NIGHT THROUGH FRIDAY/...
AS OF 210 AM SATURDAY...

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 100 AM SATURDAY...

AFTER INITIALLY VFR CONDITIONS...THE PASSAGE OF A STRONG DEEP LAYER
FRONTAL ZONE WILL RESULT IN A RAPIDLY EXPANDING...BUT NARROW...
PRECIPITATION AXIS ACROSS THE WEST-CENTRAL CAROLINAS BETWEEN 09-15Z.
THE PRECIPITATION AXIS WILL THEN EXPAND IN AREAL EXTENT AND PIVOT
EASTWARD ACROSS CENTRAL NC THROUGH THIS EVENING...OWING TO THE
AMPLIFICATION OF A STRONG TROUGH ALOFT FROM THE CENTRAL PLAINS TO
THE SOUTHEAST STATES. THE PRECIPITATION WILL LIKELY BEGIN AS A MIX
OF RAIN AND SNOW...BEFORE GRADUALLY TRANSITIONING TO ALL SNOW FOR
THE AFTERNOON AND EVENING HOURS. CEILINGS AND VISIBILITY
RESTRICTIONS WILL CONSEQUENTLY FALL INTO MVFR-IFR RANGE...BEFORE THE
STEADY PRECIPITATION ENDS AND SKIES CLEAR FROM WEST TO EAST THIS
EVENING. A FEW LINGERING SNOW SHOWERS WILL BE POSSIBLE THROUGH
MIDNIGHT...HOWEVER...AS THE VERY COLD AND DYNAMIC TROUGH AXIS ALOFT
PIVOTS EASTWARD.

LOOKING AHEAD: BREEZY CONDITIONS SUNDAY...FOLLOWED BY ANOTHER
FRONTAL SYSTEM AND ASSOCIATED SUB-VFR CONDITIONS AND RAIN THAT WILL
AFFECT THE REGION TUE.

RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 PM SATURDAY TO 4 AM EST SUNDAY FOR
NCZ007>011-025>028-041>043-077-078-085-086-088-089.

SYNOPSIS...MWS
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...MWS

AREA FORECAST DISCUSSION...UPDATED

NWS GRAND FORKS ND

617 PM CST SUN FEB 17 2013

.UPDATE...-FZRA/SLEET OCCURRING COOPERSTOWN INTO GRAND FORKS AND
WILL UPDATE THE FORECAST TO INCLUDE. 850MB/925MB TEMPS COOL BY 03Z
AND WILL GO ALL SNOW AFTER THIS TIME. IN ORDER TO NOT COMPLICATE
THINGS WITH TOO MANY HAZARDS...WILL ISSUE A NOWCAST FOR THIS
SITUATION SINCE IT WILL BE SHORT LIVED.

.AVIATION...
-FZRA LIKELY FOR KGFK AND KTVF EARLY THIS EVENING. FOCUS TONIGHT
INTO MONDAY WILL BE TIMING OF WIND SHIFT AND THEN VSBY/CIGS WITH
SNOW EXPECTED ESP DVL-GFK-TVF REGIONS. BASED WIND CHANGE AND SNOW
TIMING ON RAP MODEL WITH STRONG WINDS NOT HITTING TIL A FEW HOURS
AFTER FRONTAL PASSAGE. VSBYS AND CIGS MONDAY MAY BE QUITE VARIABLE
BUT GENERALLY IFR DVL- GFK-TVF IN BLSN...FARGO- BJI A MIX OF MVFR
AND IFR MAINLY DUE TO VSBYS. WINDS IN THE RED RIVER VALLEY AND DVL
REGION WILL GUST TO 40 KTS OR HIGHER AT TIMES MONDAY WITH 25 TO 30
KTS PSBL MON AFTN IN BEMIDJI.

.PREV DISCUSSION... /ISSUED 319 PM CST SUN FEB 17 2013/

SHORT TERM...
MAIN CHALLENGE FOR THIS PORTION OF THE FORECAST WILL BE HOW TO
HANDLE HEADLINES WITH THE LOW CROSSING THE AREA TONIGHT INTO
MONDAY. MODELS STILL HAVE SOME SUBTLE DIFFERENCES IN REGARD TO
SNOWFALL AMOUNTS TONIGHT BUT GUSTY WIND LOOKS LIKE A SURE BET.

TONIGHT...SFC LOW IS CURRENTLY OVER NORTH CENTRAL/NORTHEAST ND
WITH VERY MILD AIR ASSOCIATED WITH IT. GETTING A SOUTHWEST SFC
COMPONENT TO THE WINDS OVER THE FAR WESTERN FA WHERE TEMPS HAVE
CLIMBED INTO THE LOW TO MID 30S. OTHER AREAS WILL PROBABLY SEE
SOME LATE AFTERNOON OR EARLY EVENING RISE BEFORE FALLING LATE.
STIFF SOUTH WINDS ARE CAUSING SOME DRIFTING SNOW ACROSS SOME ROADS
AND WITH THE MILD ROAD TEMPS ARE MELTING AND THEN REFREEZING.
OTHERWISE THE WARM TEMPS SHOULD BE GIVING A BIT OF A CRUST TO THE
SNOW IN THOSE AREAS ABOVE 32F. RADAR STILL SHOWING SOME ECHOES
ACROSS THE EAST BUT ONLY KBDE/KFGN ARE STILL REPORTING SOME LIGHT
SNOW. NOT REALLY EXPECTING SNOW ACROSS THE SOUTHERN FA PRIOR TO
MIDNIGHT. THERE SHOULD BE IN THE NORTH THOUGH WITH BEST CHANCES
ALONG THE CANADIAN BORDER. NEW 18Z NAM HAS COME IN SHOWING A BAND
DEVELOPING ACROSS THE CENTRAL RED RIVER VALLEY IN THE EVENING
WHICH LOOKS A LITTLE ODD. THE 12Z GFS SHOWS A BAND DEVELOPING
ACROSS CENTRAL ND AND LIFTING INTO THE NORTHERN RED RIVER VALLEY.
ECMWF SEEMS PRETTY CONSISTENT IN HITTING NORTHEAST ND INTO
PORTIONS OF NORTHWEST MN OR AREAS MAINLY NORTH OF HIGHWAY 2 WITH
THE MOST SNOW. THEREFORE WILL STICK WITH THE IDEA OF 3 TO 6 INCHES
ACROSS THIS AREA TAPERING TO LITTLE OR NOTHING ACROSS THE FAR
SOUTH. WIND SPEEDS WILL NOT KICK IN UNTIL LATE TONIGHT. GENERALLY
EXPECTING THIS AFTER MIDNIGHT IN THE FAR NORTH AND AROUND 09Z MON
IN THE KGFK AREA. STRONG WINDS SHOULD NOT HIT THE KFAR AREA DOWN
TO WAHPETON UNTIL 12Z OR LATER. WITH SNOW AND WIND POTENTIAL WILL
ISSUE BLIZZARD WARNINGS FOR NORTHEAST ND INTO THE RED RIVER VALLEY
COUNTIES OF EXTREME NORTHWEST MN STARTING AFTER MIDNIGHT. WITH THE
SNOWFALL UNCERTAINTIES WILL LEAVE THE VALLEY CITY TO FARGO TO ADA
AREA IN THE BLIZZARD WATCH YET. WILL COVER THE FAR SOUTH WITH A
WINTER WEATHER ADVISORY WHICH WILL HAVE TO BE MONITORED IF THE
SNOW MAKES IT FURTHER SOUTH. WENT WITH WINTER STORM WARNING FOR
THE ROSEAU TO KTVF AREA AND LAKE OF THE WOODS AREA FOR 4 TO 6
INCHES OF SNOW WITH GUSTY WINDS. WILL LEAVE THE MAHNOMEN TO KBJI
AREA IN A WINTER STORM WATCH DUE THE UNCERTAINTY WITH SNOWFALL
YET.

MON-WED...WINDS SHOULD BE GOING PRETTY WELL BY SUNRISE AND SHOULD
CONTINUE HOWLING THROUGH THE DAY. LEFT ALL HEADLINES IN EFFECT
THROUGH 00Z TUE EXCEPT THE WINTER WEATHER ADVISORY AREA...WHICH
GOES UNTIL 03Z TUE. OTHER AREAS MAY NEED SOME EXTENDING OR
TWEAKING BUT LATER SHIFTS CAN ALWAYS DO THIS. SFC HIGH BUILDS IN
ON TUE AND SHOULD KEEP THINGS CLEAR THRU MOST OF WED. THIS WILL
SET THE STAGE FOR SOME COLD DAYS AND NIGHTS AND THE POTENTIAL FOR
SOME WIND CHILL ISSUES WHICH WILL NEED TO BE ADDRESSED LATER.

LONG TERM (THU-SUN)...
MAIN ISSUE REVOLVE AROUND THE NORTHWARD EXTENT OF PRECIPITATION FROM
THE CENTRAL PLAINS STORM. GEM/GFS/EURO ALL BRING SFC LOW INTO
KANSAS THURSDAY THEN MOVE IT NORTHEAST AND WEAKEN WITH WITH TIME
WHILE A LARGE UPPER LOW FORMS IN NEBRASKA AND DRIFTS NORTH INTO THE
EASTERN DAKOTAS FRI. MODEL DIFFERENCES CONCERN THE AMOUNT OF PRECIP
THAT WILL SPREAD NORTH AS STORM WEAKENS...WITH 00Z-12Z ECMWF STILL A
BIT MORE WET THAN GFS AND ESP THE GEM. THAT SAID WILL CONTINUE WITH
GENERAL MODEL BLEND FORECAST OF LIKELY POPS OR HIGH CHANCE IN THE
SOUTH THURSDAY NIGHT INTO FRIDAY...WITH LOWER POPS NORTH. ALL
MODELS KEEP UPPER LOW AROUND SAT-SUN WITH SOME CHANCES FOR VERY
LIGHT SNOW.

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR NDZ049-
052-053.

BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR NDZ016-024-
026>030.

BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR
NDZ006>008-014-015-054.

BLIZZARD WATCH FROM 6 AM CST MONDAY THROUGH MONDAY AFTERNOON FOR
NDZ038-039.

MN...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR MNZ027-
029>031-040.

WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH MONDAY
AFTERNOON FOR MNZ015>017-022.

BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR MNZ001-004-007.

WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR MNZ005-006-008-
009-013-014.

BLIZZARD WATCH FROM 6 AM CST MONDAY THROUGH MONDAY AFTERNOON FOR
MNZ002-003.

$$
TG

AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

320 PM CST SAT FEB 16 2013

.SHORT TERM...
TEMPS TONIGHT A CHALLENGE ONCE AGAIN. LOW CLOUDS/FOG FROM THIS
MORNING CLEARED OFF AND A SOUTH-SOUTHEAST WIND HELPING TO WARM
THINGS UP A BIT...BUT TEMPS QUITE VARIABLE WITH TEMPS STRUGGLING
INTO THE MID TEENS IN MOST OF THE FCST AREA WHILE A FEW SPOTS IN
THE MN TREES SEEING MID 20S. AREA OF CLOUD COVER DVL-JMS REGION
REALLY BREAKING UP SOME THIS AFTN BUT IDEA IS THESE CLOUDS ASSOC
WITH 850MB WARM ADV WILL SPREAD EAST TONIGHT. UPSTREAM CANADIAN
RADAR AND OBS SHOWS SOME LIGHT SNOW BRANDON-DAUPHIN-PORTAGE MB
REGION AND DID COORD WITH WFO BIS AND SPREAD SOME FLURRIES
SOUTHEAST THIS EVENING INTO NE ND. FOR LATER TONIGHT...CLOUD BAND
MOVES MORE INTO MN FCST AREA AND RAP ISENTROPIC FCSTS INDICATE
SOME LIFT 750-850 MB REGION DEVELOPING IN BDE-BJI AREA BY 12Z SUN.
THUS KEPT LOW POP FOR -SN IN LAKE OF THE WOODS REGION AND SPREAD
MENTION OF FLURRIES A BIT MORE BACK INTO NRN VALLEY AND REST OF NW
MN. BUFKIT SOUNDINGS SHOW PTYPE ALL -SN THRU 12Z.

AS FOR TEMPS...QUITE CHALLENGING AS SHOULD SEE SOME DROP AGAIN IN
THE EAST BUT OTHERWISE FAIRLY STEADY IF NOT RISE A BIT OVERNIGHT
IN ERN ND. USED A BLEND OF MODEL GUIDANCE FOR HOURLY TEMPS.

FOR SUNDAY...MAIN ISENTROPIC LIFT HANGS OVER LAKE OF THE WOODS
REGION WITH MAJORITY OF THE FCST IN DRY SLOT AT 850 MB. SOUNDINGS
DO SHOW SOME 925 MB MOISTURE BUT LIFT IN THAT LAYER APPEARS
INSUFFICIENT TO PRODUCE ANY FZDZ WE HAD IN THE PREV FCST. THROUGH
COORD WITH ABR/MPX/BIS REMOVED FZDZ MENTION SUNDAY. PTYPES IN FAR
NW MN WHERE POPS ARE WOULD BE -SN. TEMPS SHOULD WARM ESP LATER ON
IN THE DAY AS WINDS TURN A MORE WEST AND ALLOW TEMPS TO WARM INTO
THE LOWER 30S. OTHERWISE EXPECT A STIFF SOUTH-SOUTHEAST WINDS LATE
TONIGHT THRU SUNDAY MIDDAY.

12Z GFS MODEL A BIT MORE LIKE THE OTHER MODELS NOW IN REGARDS TO
SUN NIGHT-MON SYSTEM. 00Z/06Z SAT RUNS A BIT AGGRESSIVE. SFC LOW
WILL MOVE FROM EC SASK INTO SW MB SUNDAY AFTN THEN TOWARD LAKE OF
THE WOODS REGION 06Z MON. MAIN SNOW WITH THIS LOW AND KEPT IDEA OF
2-4 INCHES IN RRT/BDE AREAS. OTHERWISE MAIN ACTION WILL WAIT WITH
COLD FRONT WHICH WILL DROP DOWN SUN LATE NIGHT INTO MONDAY
MORNING. SHOULD SEE SOME LIGHT SNOW WITH THIS...MORE SNOW
SHOWERY...ALONG WITH A PD OF STRONG WINDS MONDAY. BUFKIT SOUNDINGS
SHOW ADIABATIC TO AROUND 880 MB AT GFK/FAR MONDAY MIDDAY WHERE
WINDS OF 30-35 KTS SHOULD MIX DOWN. STRONG COLD ADV AS WELL AS
HIGH BUILDS IN AND SFC LOW STRENGTHENS TO OUR EAST. ISSUED A
SPECIAL WX STATEMENT FOR MONDAY AS WIND AND LIGHT SNOW WILL CAUSE
BLOWING SNOW AND LIKELY NASTY TRAVEL CONDITIONS.

TEMPS TO DROP WELL BLOW ZERO MONDAY NIGHT AND RECOVER ONLY
SLIGHTLY TO THE SINGLE DIGITS ABOVE AND BLO ZERO TUESDAY WITH
DIMINISHING WINDS. WIND CHILLS THOUGH EARLY TUESDAY MAY DROP TO
-30 TO -35F IN NE ND.

.LONG TERM (TUE NIGHT-SAT)...
MID LEVEL RIDGING AND SFC HIGH PRESSURE SHOULD BE OVER THE FA TO
START THE LONG TERM PERIOD. WITH THE SFC HIGH AND A COLD AIRMASS IN
PLACE TEMPS WILL STILL BE CHILLY TUE NIGHT INTO WED. FLOW WILL
TRANSITION BACK TO THE SOUTHWEST WITH ANOTHER COLORADO LOW SYSTEM
EJECTING OUT ON THU. HPC MEAN TAKES THIS LOW FROM SE COLORADO AT 12Z
THU TO NEAR CHICAGO BY 12Z FRI WHICH USES A GLOBAL MEAN. LATEST RAW
12Z MODEL GUIDANCE FROM BOTH THE ECMWF AND GFS IS FURTHER WEST WITH
THE SFC LOW. THEREFORE THERE IS STILL UNCERTAINTY WITH THE TRACK OF
THIS NEXT SYSTEM YET. AS FOR NOW WILL LEAVE HIGHER THAN GUIDANCE
PCPN CHANCES ACROSS THE SOUTHEAST FA FOR THU INTO THU NIGHT AND SEE
WHAT LATER RUNS HAVE IN STORE. MAY BE LINGERING LIGHT SNOW FROM THIS
SYSTEM ALL THE WAY INTO SAT.

.AVIATION...
CLOUD COVER REMAINS THE MAIN AVIATION CHALLENGE. HAD THOUGHT SOME OF
THE CLOUDS TO THE WEST OR NORTH WOULD WORK INTO THE VALLEY DURING
THE AFTERNOON BUT THEY HAVE BEEN THINNING INSTEAD. EITHER WAY THE
HEIGHT RANGES WOULD BE IN THE VFR RANGE. SHOULD SEE STEADY SOUTH
WINDS TONIGHT BECOME GUSTY BY SUNDAY MORNING.

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

$$
RIDDLE/GODON

AREA FORECAST DISCUSSION

NWS WILMINGTON OH

348 PM EST SAT FEB 16 2013

.SYNOPSIS...
IN THE WAKE OF A DEPARTING UPPER LEVEL TROUGH...HIGH PRESSURE
WILL BUILD OVER THE AREA ON SUNDAY. RETURN FLOW AND SOUTHERLY
WINDS WILL BRING WARMER AIR TO THE REGION MONDAY AND OVERNIGHT
AHEAD OF THE NEXT COLD FRONT THAT WILL CROSS LATE MONDAY NIGHT.
RAIN WILL OVERSPREAD THE REGION AHEAD OF THIS NEXT FRONTAL
PASSAGE.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPPER LEVEL TROUGH IS MOVING EAST THROUGH THE NORTHERN OHIO
VALLEY/GREAT LAKES REGION TONIGHT. THE BEST COLD PUSH IS ONGOING
RIGHT NOW AND HELPING TO CONTINUE THE CONVECTION GOING ON THIS
AFTERNOON. WITH THE LOSS OF DAYTIME INSOLATION THE SURFACE WILL
COOL OFF TONIGHT AND THERMAL DIFFERENTIAL CAUSING THE SNOW
SHOWERS WILL QUICKLY DISSIPATE THIS EARLY EVENING...EVEN AS THE
COLDEST AIR CONTINUES TO SETTLE OVER THE REGION LATE TONIGHT.

NAM AND HRRR WERE PREVIOUSLY SHOWING A WEAK AREA OF FORCING AND
LIGHT SNOW RUNNING FROM ABOUT INDIANAPOLIS AT 0Z TONIGHT TOWARDS
CINCINNATI AROUND 6Z AND THEN SOUTH OF A MAYSVILLE/VANCEBURG LINE
BY DAYBREAK. I INCLUDED SOME LIGHT SNOW IN THESE AREAS BUT THE
ACTUAL OCCURRENCE OF THIS EVENT REMAINS TO BE SEEN AND MAY NOT
MATERIALIZE.

SKY COVER IS QUITE CELLULAR LOOKING IN NATURE AND SHOULD DISSIPATE
RELATIVELY QUICKLY OUTSIDE OF CENTRAL OHIO TONIGHT...AND IN THE
INDY-CINCY-NORTHERN KY LINE PREVIOUSLY MENTIONED FOR INCREASED
SNOW POTENTIAL. THIS RELATIVE CLEARING WILL LET TEMPERATURES DROP
INTO THE TEENS WITH SOME SINGLE DIGITS POSSIBLY IN COLDER LOW-
LYING AREAS.

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A BRIEF RESPITE BETWEEN SYSTEMS WILL BE FOUND SUNDAY AND WARMER
AIR WILL REALLY BEGIN TO BE USHERED IN MONDAY AFTER A MINOR DROP
OR RELATIVELY STEADY TEMPERATURES IN THE LOWER 20S SUNDAY NIGHT.

MILD AIR ON MONDAY AND OVERNIGHT WILL BE SHORT LIVED. RAIN WILL
SPREAD EAST IN THE EVENING AS THE DAYTIME SHOULD JUST SEE
INCREASING CLOUD COVER FROM WEST TO EAST. THE RAIN WILL BE
EVERYWHERE BY MIDNIGHT AND IS EXPECTED TO TAIL OFF QUICKLY WITH
THE PASSAGE OF THE FRONT...BEFORE DAYBREAK IN INDIANA. WINDS WILL
SHIFT WEST BEHIND THE FRONT AND DRIER AIR BEING USHERED IN WILL
MARK THE END OF THE RAIN. TEMPERATURES IN THE WARM SECTOR MONDAY
SHOULD RISE INTO THE UPPER 40S AND LOW 50S...WITH SOME MID 50S
POSSIBLE IN KENTUCKY.

.LONG TERM /TUESDAY THROUGH SATURDAY/...
PERIOD BEGINS WITH A CDFNT FORECASTED TO BE PUSHING ACROSS THE
FA. EXACT PLACEMENT OF THE FRONT AT 12Z TUESDAY WILL AFFECT THE
PCPN TYPE AND POPS FOR THE FIRST FEW HOURS OF THE DAY. THE 12Z NAM
APPEARS TO BE THE QUICKEST WITH THE FRONT...PUSHING IT INTO THE
APPALACHIANS ALREADY. THE MORE GLOBAL MODELS HAVE THE FRONT
SLOWER...MAYBE AROUND I-75. TRENDED TOWARDS THE CONSENSUS...THUS
KEPT LIKELY POPS IN THE E AHEAD OF THE FNT...BUT DRIED OUT THE
POPS POST FRONTAL. WITH FROPA SO EARLY...WILL PROBABLY SEE FALLING
OR STEADY TEMPERATURES FOR TUESDAY. ALSO THREW IN A MENTION OF A
CHC OF SNOW SHOWERS FOR LATE TUE MORNING INTO TUE AFTN AS THE
MODELS ARE SHOWING CYCLONIC SFC FLOW COMBINING WITH WLY CAA AT H8.

HIGH PRESSURE BUILDS DOWN INTO THE LOWER OHIO VALLEY TUE NIGHT
INTO WED BEFORE LIFTING NE ACROSS THE FA WED NGT. THIS SHOULD
PROVIDE DRY CONDITIONS FOR THE PERIOD...WITH NRN SECTIONS SEEING
MORE CLOUDS THAN THE S TUE NGT AND WED...BEFORE MOSTLY CLEAR SKIES
PREVAIL WED NGT.

SYSTEM DIGS INTO THE SRN ROCKIES WED NGT...THEN EJECTS OUT THU
INTO THU NGT. MODELS ARE SHOWING THEIR TYPICAL SPREAD. THE CMC IS
THE QUICKEST THIS RUN IN BRINGING RETURN PCPN TO THE FA THU AFTN.
THE 12Z RUNS OF THE GFS AND ECMWF ARE SLOWER...LIMITING POPS TO
THE SW. THICKNESSES WILL BE COLD ENUF FOR SOME RAIN/SNOW AT THE
ONSET. AS THE CENTER OF THE SYSTEM LIFTS OUT THRU THE PLAINS...AN
AREA OF PCPN WILL BE PUSHED ACROSS THE FA THU NGT INTO FRI. PCPN
WILL EITHER BE SN OR RA/SN MIX UNTIL A WRMFNT GRADUALLY BRINGS IN
WARMER AIR CHANGING THE PCPN TO RA BEFORE IT ENDS ON FRIDAY. HIGH
PRESSURE THEN BUILDS IN FOR FRIDAY.

COLD AIR WILL WORK IN TUESDAY NIGHT DROPPING TEMPERATURES IN THE
TEENS AND LOWER 20S. THE COOL NLY FLOW ON WED WILL KEEP TEMPS DOWN
IN THE UPPER 20S N TO THE MID 30S NRN KY. THE CLEAR SKIES WILL
ALLOW TEMPERATURES TO DROP BACK INTO THE TEENS AND LOWER 20S
AGAIN. ONLY EXPECT HIGHS ON THU TO MAKE THE 30S AHEAD OF THE STORM
SYSTEM...BUT WITH RISING TEMPS THU NGT. HIGHS FRIDAY SHOULD MAKE
THE 40S AS THE REGION GETS WARM SECTORED.

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD FLURRIES AND OCCASIONAL BRIEF HEAVY SNOW SHOWERS WILL
CONTINUE TO AFFECT THE CMH/LCK/ILN/DAY TERMINALS THROUGH ABOUT 21Z
BEFORE SHIFTING EAST OF THE AREA. EXPECT MAINLY VFR/MVFR
CONDITIONS IN THIS TIME...BUT IN THE HEAVIEST OF SNOW SHOWERS
COULD SEE IFR OR EVEN LIFR VSBYS FOR A BRIEF PERIOD OF TIME AND
CIGS AROUND 1500FT. SECONDARY SUBTLE WAVE UPSTREAM OVER WI/IL/IA
EXPECTED TO POSSIBLY BRING A MUCH SMALLER/MORE LIMITED SWATH OF
SNOW TO CVG-AREA TERMINALS AFTER SUNSET...WITH LOW CONFIDENCE ON
TIMING. WENT WITH A MIDDLE OF THE ROAD 04Z-07Z TIMEFRAME WHICH IS
A LITTLE LATER THAN RAP AND A LITTLE EARLIER THAN NAM-WRF...BUT
DON/T EXPECT OVERALL IMPACTS FROM THIS TO BE LARGE...THINKING MVFR
CONDITIONS AT WORST. CLOUDS OVERNIGHT AND ESP INTO SUNDAY MORNING
ARE PROBLEMATIC...WAS NOT EAGER TO IMPROVE MVFR/VFR BKN CIGS
OVERNIGHT DESPITE PASSAGE OF UPPER TROUGH AND DEEPER SUBSIDENCE.
THERE IS SOME LOW CLOUD UPSTREAM CAUGHT UNDERNEATH THE WEAK
SURFACE FLOW /RIDGE AXIS/ WHERE THE LOW LEVEL FLOW TURNS FROM NWLY
TO SWLY BUT SOME OF THIS IS ALSO OPEN- CELLULAR IN NATURE. IN
GENERAL DELAYED THE CLEARING FROM BKN-SCT A FEW HOURS FROM
INHERITED TAFS...THOUGH A PERIOD OF CLEARING IS POSSIBLE NEAR CVG
LATE THIS AFTN/EVE BEFORE NEXT BATCH OF MOISTURE ARRIVES.

OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE MONDAY NIGHT AND EARLY
TUESDAY.

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

$$
SYNOPSIS...FRANKS
NEAR TERM...FRANKS
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...BINAU

AREA FORECAST DISCUSSION

NWS WILMINGTON OH

143 PM EST SAT FEB 16 2013

.SYNOPSIS...
AN UPPER LEVEL TROUGH MOVING ACROSS THE GREAT LAKES WILL RESULT IN
SEASONABLY COOL TEMPERATURES AND A CHANCE OF SNOW SHOWERS TODAY.
HIGH PRESSURE WILL BUILD INTO THE AREA ON SUNDAY BEFORE A LOW
PRESSURE SYSTEM MOVES IN FROM THE WEST MONDAY NIGHT. INCREASING
SOUTHERLY FLOW AHEAD OF THE LOW WILL RESULT IN MUCH WARMER TEMPERATURES
BY MONDAY.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
16.12Z KILN RAOB SAMPLED THE IMPORTANT ASPECTS OF THE COLD/SHARP
TROUGH THAT IS SHIFTING THROUGH THE AREA TODAY. WITH 500MB
HEIGHTS/TEMPS NEAR 5250M/-40C RESPECTIVELY...THIS IS AN
IMPRESSIVELY DEEP SYSTEM THAT WILL LEAD TO YET ANOTHER DAY OF
HIGHLY VARIABLE/CHANGEABLE WEATHER INCLUDING SNOW SHOWERS WITH LOW VSBYS.
THE STEEP LOW LEVEL LAPSE RATE ENVIRONMENT IS ALREADY IN PLACE PER
THE 12Z SOUNDING /850MB TEMPS TO -14C/ AND THESE SHOULD FALL
FURTHER TOWARD -17C INTO THIS EVENING...AND WITH THE TROUGH AXIS
STILL TO THE WEST...TROPOSPHERIC COOLING /DECREASING STABILITY/
WILL CONTINUE TO SUPPORT AN INCREASE IN CLOUDS AND EVENTUALLY SNOW
SHOWER DEVELOPMENT.

THERE GENERALLY IS STRONG AGREEMENT FROM THE CONVECTION-ALLOWING
SUITE OF GUIDANCE INCLUDING HRRR/SPC-WRF/NSSL-WRF THAT AREA OF
SNOW SHOWERS NOW DEVELOPING TO OUR NORTHWEST/WEST WILL INCREASE IN
COVERAGE/INTENSITY AS IT MOVES THROUGH OUR AREA LATE THIS
MORNING/AFTN...WITH HIGHEST COVERAGE NORTH OF I-70...AND LEAST
COVERAGE OVER NRN KY AND SERN IN. HAVE INCREASED SNOW CHANCES MOST
AREAS FROM 16Z-21Z AND INDICATED ACCUMS UP TO AN INCH IN THE
NORTH...THOUGH ACTUAL ACCUMS WILL BE HIGHLY DEPENDENT ON THE VERY
SMALL SCALE CONVECTIVE SNOW BURSTS. RAP/NAM FCST BUFR SOUNDINGS
/C25...KCMH...AND KILN/ ALL SUGGEST THAT DESPITE THE SHALLOW
NATURE OF MOISTURE/CONVECTIVE SNOW SHOWERS...THAT SUPERSATURATION
WITH RESPECT TO ICE IS LIKELY TO EXIST IN THE MOST INTENSE SQUALLS
IN -12C TO -18C REGION OF SOUNDING WHICH WOULD LEAD TO LARGE
DENDRITIC FLAKES AND HEAVY RATES /LOW VSBYS/ EVEN IN SHORT DURATION.

ACCUMULATIONS WON/T BE THE IMPACT THOUGH...IT WILL BE RAPID
REDUCTIONS IN VSBYS TO BELOW 1/2SM IN THE HEAVIEST SQUALLS...AND
WITH A VERY COLD START THIS MORNING ROAD TEMPS MAY NOT BE AS
RECEPTIVE TO MELTING...ESPECIALLY WITH WINDS COMING UP A BIT OUT
OF THE NW THIS AFTERNOON AND TEMPS REMAINING IN THE 20S. SO THE
AMBIENT SETUP SEEMS TO SUPPORT A HIGHER THAN NORMAL THREAT OF
RAPIDLY CHANGING ROAD CONDITIONS AND VISIBILITIES THAT MAY LEAD TO
MORE SIGNIFICANT IMPACTS ON OUR INTERSTATE HIGHWAY SYSTEM WITHIN
THESE INTENSE SNOW BURSTS. WILL BE AGGRESSIVE WITH SPECIAL WEATHER
STATEMENTS AND HWO WORDING AS THE SNOW SHOWERS DEVELOP LATER THIS MORNING/AFTN.

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
THE UPPER LEVEL TROUGH AXIS WILL BEGIN TO SHIFT EAST OF THE AREA
BY TONIGHT WITH MID/UPPER LEVEL RIDGING SLIDING OVERHEAD SUNDAY
NIGHT INTO MONDAY. THIS WILL ALLOW FOR DRYING CONDITIONS AND
DECREASING CLOUDS BY SUNDAY. HOWEVER...WE DO NOT REALLY GET INTO
RETURN FLOW UNTIL SUNDAY NIGHT SO EXPECT SUNDAY TO REMAIN ON THE
COOLER SIDE WITH HIGHS ONLY IN THE UPPER 20S TO LOWER 30S.

WE COULD HAVE SOME EARLY LOWS SUNDAY EVENING WITH TEMPERATURES
THEN STEADYING OFF OR EVEN RISING A LITTLE LATE AS LOW LEVEL SOUTHERLY
FLOW BEGINS TO PICK UP AND WE GET SOME INCREASING CLOUDS.
INCREASING SOUTHWESTERLY LOW LEVEL FLOW THROUGH THE DAY ON MONDAY
WILL LEAD TO GOOD WAA AND SOME BREEZY CONDITIONS. THIS SHOULD
PUSH TEMPERATURES WELL ABOVE NORMAL WITH HIGHS ON MONDAY INTO THE
UPPER 40S TO LOWER/MID 50S. STRENGTHENING ISENTROPIC LIFT THROUGH
THE DAY WILL LIKELY ALLOW FOR SOME SHOWERS TO DEVELOP THROUGH MID
TO LATE AFTERNOON...ESPECIALLY ACROSS THE WEST.

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL BEGIN TO WORK INTO THE AREA OVERNIGHT MONDAY
NIGHT AND MOVE EAST OF THE REGION TUESDAY MORNING. THIS FEATURE
WILL ALLOW FOR COLDER AIR TO WORK INTO THE FA AND RAIN WILL BEGIN
TO MIX AND THEN CHANGE OVER TO SNOW OVERNIGHT MONDAY NIGHT INTO
TUESDAY. DUE TO THE FRONTAL PASSAGE TEMPERATURES WILL STRUGGLE TO
RISE ON TUESDAY AND WILL ACTUALLY FALL SLOWLY THROUGH MOST OF THE
DAY. SNOW WILL COME TO AN END TUESDAY AFTERNOON AND HIGH PRESSURE
WILL WORK INTO THE FA. WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES
TUESDAY NIGHT AND WEDNESDAY NIGHT TEMPERATURES WILL DROP DOWN INTO
THE TEENS TO THE 20S FOR LOWS.

THE NEXT STORM SYSTEM WILL BEGIN TO BRING PRECIPITATION INTO THE FA
THURSDAY AFTERNOON WITH MORE WIDESPREAD PRECIPITATION ACROSS THE FA
THURSDAY NIGHT. PRECIPITATION WILL BEGIN TO TAPER OFF ACROSS THE FA
ON FRIDAY. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW WITH THIS
SYSTEM.

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD FLURRIES AND OCCASIONAL BRIEF HEAVY SNOW SHOWERS WILL
CONTINUE TO AFFECT THE CMH/LCK/ILN/DAY TERMINALS THROUGH ABOUT 21Z
BEFORE SHIFTING EAST OF THE AREA. EXPECT MAINLY VFR/MVFR
CONDITIONS IN THIS TIME...BUT IN THE HEAVIEST OF SNOW SHOWERS
COULD SEE IFR OR EVEN LIFR VSBYS FOR A BRIEF PERIOD OF TIME AND
CIGS AROUND 1500FT. SECONDARY SUBTLE WAVE UPSTREAM OVER WI/IL/IA
EXPECTED TO POSSIBLY BRING A MUCH SMALLER/MORE LIMITED SWATH OF
SNOW TO CVG-AREA TERMINALS AFTER SUNSET...WITH LOW CONFIDENCE ON
TIMING. WENT WITH A MIDDLE OF THE ROAD 04Z-07Z TIMEFRAME WHICH IS
A LITTLE LATER THAN RAP AND A LITTLE EARLIER THAN NAM-WRF...BUT
DON/T EXPECT OVERALL IMPACTS FROM THIS TO BE LARGE...THINKING MVFR
CONDITIONS AT WORST. CLOUDS OVERNIGHT AND ESP INTO SUNDAY MORNING
ARE PROBLEMATIC...WAS NOT EAGER TO IMPROVE MVFR/VFR BKN CIGS
OVERNIGHT DESPITE PASSAGE OF UPPER TROUGH AND DEEPER SUBSIDENCE.
THERE IS SOME LOW CLOUD UPSTREAM CAUGHT UNDERNEATH THE WEAK SURFACE
FLOW /RIDGE AXIS/ WHERE THE LOW LEVEL FLOW TURNS FROM NWLY TO SWLY BUT
SOME OF THIS IS ALSO OPEN- CELLULAR IN NATURE. IN GENERAL DELAYED
THE CLEARING FROM BKN-SCT A FEW HOURS FROM INHERITED TAFS...THOUGH
A PERIOD OF CLEARING IS POSSIBLE NEAR CVG LATE THIS AFTN/EVE
BEFORE NEXT BATCH OF MOISTURE ARRIVES.

OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE MONDAY NIGHT AND EARLY
TUESDAY.

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

$$
SYNOPSIS...JGL
NEAR TERM...BINAU
SHORT TERM...JGL
LONG TERM...NOVAK
AVIATION...BINAU

AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

655 AM EST SAT FEB 16 2013

.SYNOPSIS...
A MOIST UPPER LEVEL LOW WILL CROSS THE REGION TODAY...WITH DRY HIGH
PRESSURE BUILDING IN FROM THE NORTH SUNDAY. A COLD FRONT WILL
APPROACH THE CAROLINAS AND NORTHEAST GEORGIA TUESDAY WITH ANOTHER
AREA OF CANADIAN HIGH PRESSURE BUILDING IN ON WEDNESDAY.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF EARLY SAT MORNING...UPPER TROUGH WILL SWING THROUGH THE REGION
TODAY WITH FURTHER COLD ADVECTION AND STRONG VORT MAX ACCOMPANYING
IT. VERY LIGHT PRECIP ALREADY FALLING OVER THE PIEDMONT. THIS AREA
IS FAVORED BY THE NAM...GFS...RAP AND HRRR AS BEING THE FOCUS FOR
THE BULK OF THE PRECIP. FORCING FROM THE WAVE WILL BE ENHANCED OVER
THE PIEDMONT BY LOW LEVEL CONVERGENCE BETWEEN THE INVADING ARCTIC
AIRMASS AND EXISTING COASTAL AIR. THE TROUGH STEADILY PROGRESSES
EAST...WITH THE BASE HAVING DEPARTED THE CWFA BY 00Z...WITH DEEP DRY
AIR RAPIDLY WORKING IN.

TEMPERATURE PROFILES DO NOT INDICATE A WARM NOSE GIVEN THE ALREADY
COLD AIR IN PLACE. DEEP SATURATION MEANS RAIN OR SNOW WILL MAINLY BE
DETERMINED BY SURFACE TEMP. FREEZING LEVELS ARE PRETTY LOW AND SFC
TEMPS WILL BE MOSTLY IN THE 30S OVER THE PIEDMONT. A RAIN/SNOW MIX
WILL LIKELY TRANSITION TO SNOW AS THE FREEZING LEVEL LOWERS DUE TO
THE WET BULB EFFECT. FOR QPF...SOMEWHAT TRICKY WITH OPERATIONAL
MODELS SHOWING SOME POSSIBLE CONVECTIVE EFFECTS AND LOCALIZED AREAS
SEEING SIGNIFICANTLY HIGHER AMOUNTS OF SNOWFALL. INDEED BOTH THE NAM
AND GFS SHOW UP TO A COUPLE HUNDRED JOULES OF MUCAPE THIS AFTERNOON
OVER A PORTION OF NE GA AND THE WESTERN UPSTATE. 21Z SREF BACKS THIS
UP WITH LIKELY-RANGE PROBS OF 100 J. SO THIS COULD HELP ENHANCE
TOTALS DURING THE EARLY TO MID AFTERNOON WHEN THE FORCING IS
STRONGEST ANYWAY. CHOSE MODEST QPF DERIVED FROM A MODEL BLEND WHICH
HAPPENS TO BE IN LINE WITH THE GENERAL PATTERN AND AMOUNTS OF THE
LAST FEW GFS RUNS...WITH ABOUT A QUARTER INCH SOUTHEAST OF A LINE
FROM GREENWOOD TO CHESTER. FAIRLY HIGH SNOW RATIOS OF 13-16 TO 1
WILL PRODUCE TOTALS GENERALLY OF 1 TO 2 INCHES TODAY. THIS MEETS OUR
WINTER WX ADVY CRITERIA OVER THE SRN FOOTHILLS AND PIEDMONT OF NC AS
WELL AS MOST OF THE SC PIEDMONT.

IN ADDITION TO THE SYNOPTIC FORCING...PERSISTENT NORTHWEST FLOW WILL
PRODUCE ENHANCED SNOWFALL IN THE UPSLOPE AREAS OF THE MOUNTAINS.
NONETHELESS...TOTALS ARE COMPARABLE TO PREVIOUS FCST AND EXISTING
WINTER WX ADVY WILL COVER THIS.

HIGH TEMPS TODAY WILL BE WELL BELOW NORMAL IN THE ARCTIC AIR. WITH
MOSTLY OVERCAST SKIES USED A BLEND OF GFS AND CMC-REGIONAL TEMPS.
BOTH THE GFS AND NAM QUICKLY DRY THINGS OUT BEHIND THE DEPARTING
TROUGH SO SOME BREAKS IN THE CLOUD COVER COULD COME LATE IN THE DAY
ESPECIALLY SOUTHWEST...BUT PROBABLY TOO LATE TO HAVE MUCH OF AN
IMPACT ON HIGHS. FURTHERMORE ANY SNOW COVER COULD LIMIT TEMPS FROM
RISING.

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...THE UPPER TROUGH AXIS WILL PROGRESS QUICKLY
ACROSS THE REGION TONIGHT...BRINGING A QUICK END TO ANY LINGERING
PRECIP. THE ONLY EXCEPTION WILL BE ACROSS THE FAR WESTERN NC MTNS...
AS A MOIST NW FLOW SHOULD YIELD PERSISTENT SNOW SHOWERS THROUGH THE
OVERNIGHT. THE MODELS ARE RATHER STINGY WITH QPF TONIGHT...AS THE
NAM BARELY SQUEEZES OUT .05-.1 INCH ALONG THE TENN BORDER...WHILE
THE GFS IS EVEN DRIER. THIS IS SOMEWHAT SURPRISING...AS THE MOIST
LAYER IS PROGGED TO EXTEND TO ABOUT 800 MB THROUGH THE OVERNIGHT...
WHILE H8 WINDS SHOULD BE IN THE 30-40 KT RANGE. IN ADDITION...TEMPS
IN THE MOIST LAYER ARE EXPECTED TO BE EXTREMELY COOL...AS LOW AS -19
C BY 12Z SUNDAY. THEREFORE...EVEN IF THERE IS LITTLE LIQUID
EQUIVALENT...THIS PATTERN IS SUGGESTIVE OF EFFICIENT SNOW
PRODUCTION...WITH SNOW:LIQUID RATIOS AS HIGH AS 30:1 POSSIBLE LATE
TONIGHT. THEREFORE...WE WILL FORECAST AN ADDITIONAL 1 TO 4 INCHES IN
THE USUAL NW FLOW AREAS OVERNIGHT.

TEMPS WILL BE VERY COOL TONIGHT THROUGH TOMORROW...EASILY 10 DEGREES
BELOW CLIMO. HOWEVER...WITH HEIGHTS RISING IN THE WAKE OF THE UPPER
TROUGH AXIS...THE REMAINDER OF THE SHORT TERM WILL FEATURE QUICKLY
MODERATING TEMPS THAT WILL WARM VERY CLOSE TO NORMAL BY MONDAY
AFTERNOON.

BY THE END OF THE PERIOD...A MAJOR STORM SYSTEM WILL LIFT OUT OF THE
CENTRAL PLAINS...WITH AN ATTENDANT FRONTAL BAND OF PRECIP EXPECTED
TO MARCH ACROSS THE TENN VALLEY LATE MONDAY/MONDAY NIGHT. POPS WILL
INCREASE QUICKLY FROM WEST TO EAST ACROSS OUR AREA LATE MONDAY
NIGHT...BECOMING LIKELY ACROSS THE NC MTNS BY DAYBREAK. IT STILL
APPEARS THAT PRECIP COULD BEGIN AS SNOW IN THE HIGH ELEVATIONS OF
THE NC MTNS. THERE COULD ALSO BE SOME BRIEF FREEZING RAIN IN
SHELTERED VALLEYS TUE MORNING...BUT THE PREDOMINANT P-TYPE SHOULD BE
RAIN IN ALL AREAS.

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE COLD FRONT WILL STILL BE OFF TO THE WEST
BY 12Z TUE WITH A DECENT SPREAD OF LIGHT PRECIP ACROSS MOST OF THE
CWFA...INCREASING EAST THROUGHOUT THE DAY. THE STRONGEST QG FORCING
WILL REMAIN NORTH DURING FROPA...HOWEVER A 100 KT FINGER OF THE STJ
WILL PUSH INTO MIDLANDS AND PROVIDE SOME MEASURE OF UPPER DIV
SUPPORT OVER THE SRN MOST ZONES. THE FLOW BACKS DOWN THE PROFILE AND
THE LLVL JET BECOMES ALIGNED PARALLEL TO THE BLUE RIDGE...THUS
MECHANICAL LIFT WILL BE LIMITED. ALL THIS TO SAY THE ADDITIONAL
PRECIP AMOUNTS UNTIL FROPA EARLY WED WILL BE RATHER LIGHT WITH MOST
AREAS RECEIVING LESS THAN A QUARTER INCH. THERE COULD BE SOME WRAP
AROUND -SNSH LINGERING ACROSS THE NRN MTNS THROUGH 06Z WED...BUT THE
TREND HAS BEEN FOR LESS AND LESS AVAILABLE MOISTURE...ESP WITH THE
ECMWF. IN ANY CASE...ANY AMOUNTS OF SNOW WILL BE LIGHT BTW 00Z-06Z
WED. HIGH TEMPS WILL BE TRICKY WITH ALL THE CLOUDS/PRECIP...YET
DECENT SW/LY FLOW...BUT MAXES A CAT OR SO BELOW NORMAL SEEMS
REASONABLE PER THE LLVL THICKNESS PATTERN AND SUFFICIENT LACK OF
INSOL.

THE MODELS AGREE WELL WITH THE PATTERN WED THROUGH THE END OF THE
PERIOD. A SHARP RIDGE AXIS WILL BUILD ACROSS THE PLAINS STATES AND
PROPAGATE TOWARD THE EAST COAST THROUGH 00Z FRI. THIS WILL MAINTAIN
CANADIAN HIGH PRESSURE AT THE SFC AND LOW BL THETA/E AIR WED AND
THU. GOOD INSOL...BUT N/LY FLOW WILL KEEP MAXES NEAR NORMAL
PERHAPS A DEGREE OR SO BELOW WED. A MODIFYING AIRMASS WITH
INCREASING MID/HIGH CLOUDS THU SHOULD HOLD MAX TEMPS IN CHECK AT
ABOUT 3-4 DEGREES BELOW NORMAL.

ANOTHER LOW PRESSURE SYSTEM DEEPENS AND MOVES INTO THE CENTRAL
MIDWEST BY THU EVENING. THE BEST UPPER DYNAMICS AGAIN WILL BE WELL
NORTH OF THE CWFA BY THE TIME A COLD FRONT REACHES THE NC MTNS
AROUND MID DAY FRI. THE MAIN PRECIP TYPE LOOKS TO BE ALL RAIN...WITH
SOME HIGH ELEV SNOW. AGAIN...AMOUNTS LOOK TO REMAIN ON THE LOW SIDE.
THERE COULD BE A DEVELOPING TRIPLE POINT LOW AND A MEASURE OF
SFC/BASED SHEAR STORM DEVELOPMENT FRI AFTERNOON...BUT INSTABILITY BE
A LIMITING FACTOR FOR ANY REAL STRONG/SVR CONCERN OR CONJECTURE AT
THIS POINT. THE CWFA WILL LIKELY SEE A NOTICEABLE GRADIENT OF MAX
TEMPS FRI AS THE LLVL THERMAL TROF EXITS TO THE NORTH AND A WARM
FRONT IMPINGES UPON THE AREA FROM THE SOUTH. FOR NOW...GENERALLY
THINK MAX TEMPS WILL BE A 3-5 DEGREES ABOVE NORMAL SOUTH AND ABOUT
5-8 DEGREES BELOW NORMAL NORTH OF I40.

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...LOWERING CIG LIKELY THROUGH THE MORNING. LIGHT SHOWERS
JUST BEFORE DAYBREAK HAVE BROUGHT AT LEAST BRIEF PERIODS OF MVFR
CIGS TO SITES THEY PASS OVER. KCLT HAS ALREADY DONE SO ONCE AND
SHOULD SEE THIS INCREASINGLY FREQUENTLY AS PRECIP BECOMES MORE
WIDESPREAD...BUT AN EVENTUAL SOLID MVFR DECK WILL DEVELOP. MIDDAY
PEAK IN PRECIP ACTIVITY EXPECTED AHEAD OF UPPER TROUGH PASSAGE.
PRECIP WILL BEGIN AS A RAIN/SNOW MIX BUT A GRADUAL CHANGEOVER TO ALL
SNOW SHOULD OCCUR...PROBABLY BY LATE MORNING. SHORT TERM GUIDANCE
PRODUCES MVFR VSBY IN MOST AREAS AFFECTED BY PRECIP...SO TIED VSBY
FCST TO PRECIP. CIGS LIFT TO VFR BY AFTERNOON THEN SCATTER AFTER 00Z
SUN. NW WINDS THRU THE PERIOD. BIGGEST GUST POTENTIAL IS THIS
EVENING AS ARCTIC AIR BLASTS IN PROMOTING MIXING.

ELSEWHERE...CIGS WILL LOWER WITH INCREASING DEEP MOISTURE BY MID
MORNING. INITIAL -SHRA/-SHSN WILL BRING IN AT LEAST BRIEF MVFR CIGS
PRIOR TO THE WIDESPREAD LOWERING. MVFR CIGS WILL ACCOMPANY PRECIP IN
THE LATE MORNING WEST TO MIDDAY EAST. RA/SN MIX WILL TRANSITION TO
ALL SNOW FAIRLY QUICKLY AS FREEZING LEVELS ARE ALREADY LOW AND
COLDER ARCTIC AIR WORKING IN WILL FURTHER LOWER THEM. HIGH
CONFIDENCE IN AT LEAST SCATTERED PRECIP SO INCLUDED AT ALL SITES
THROUGH THE AFTN. RETURN TO VFR BY LATE AFTN WITH GUSTS POSSIBLE
FROM MIDDAY THROUGH THE END OF THE PERIOD AS COLD ADVECTION
MAINTAINS DEEPLY MIXED SFC LAYER. NO FOG EXPECTED TONIGHT WITH THE
INCOMING DRY ARCTIC AIR MASS...BUT CONTINUING UPSLOPE EFFECTS COULD
PRODUCE -SHSN AND A VFR CIG IN THE MOUNTAINS NEAR THE TN BORDER.

OUTLOOK...CONDITIONS WILL GENERALLY REMAIN DRY WITH VFR CONDITIONS
SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION EARLY NEXT WEEK.

CONFIDENCE TABLE...

12-18Z 18-24Z 00-06Z 06-12Z
KCLT HIGH 81% MED 65% HIGH 100% HIGH 100%
KGSP MED 61% LOW 50% HIGH 100% HIGH 100%
KAVL HIGH 83% MED 72% HIGH 100% HIGH 100%
KHKY MED 74% MED 71% HIGH 100% HIGH 100%
KGMU MED 62% LOW 51% HIGH 100% HIGH 100%
KAND MED 62% MED 70% HIGH 100% HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

.FIRE WEATHER...
DRY AND BREEZY TO WINDY CONDITIONS ARE EXPECTED ON SUNDAY.
HOWEVER...THE LOWEST RH VALUES WILL BE MID TO LATE AFTERNOON...WHILE
THE WINDIEST CONDITIONS SHOULD BE IN THE MORNING THROUGH EARLY
AFTERNOON. IN ADDITION...WE WILL HAVE TO WAIT AND SEE HOW MUCH
PRECIPITATION FALLS OVER THE NEXT 24 TO 36 HOURS IN ORDER TO ASSESS
FUEL MOISTURE CONTENT AND ASSOCIATED FIRE DANGER FOR LATE THIS
WEEKEND.

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST SUNDAY FOR NCZ033-
048>052-058.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ053-
065-068>072-082-501-503-505-507>510.
SC...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR SCZ002-
003-005>009-012>014.

$$
SYNOPSIS...SBK
NEAR TERM...WIMBERLEY
SHORT TERM...JDL
LONG TERM...SBK
AVIATION...WIMBERLEY
FIRE WEATHER...HG

AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

414 AM EST SAT FEB 16 2013

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...VFR CIG WITH UNLIMITED VSBY EXPECTED TO PERSIST FOR MUCH
OF THE NIGHT. NAM AND GFS GUIDANCE BOTH INDICATIVE OF PRECIP
DEVELOPING OVER THE NC PIEDMONT JUST BEFORE DAYBREAK IN AREA OF LLVL
CONVERGENCE ASSOCIATED WITH FURTHER PUSH OF COLD AIR. GFS AND ITS
DERIVATIVES BRING THIS IN WITHOUT RESTRICTIONS WHILE THE NAM FAMILY
SHOWS LOW MVFR TO IFR CIGS. CAN/T TOTALLY DISREGARD THIS THOUGH THE
FORCING IS NOT IDEAL AND BOTH MODELS ARE OVERDOING PRECIP ATTM.
LOWERING CIG LIKELY THROUGH THE MORNING SO TO HANDLE THE POTENTIAL
JUST MOVED THE MVFR UP TO 11Z. 00Z MODEL PACKAGE STILL SUPPORTIVE OF
A MIDDAY PEAK IN PRECIP ACTIVITY AHEAD OF UPPER TROUGH PASSAGE. SFC
TEMPS MAY BE ABOVE FREEZING THOUGH SNOW WOULD STILL BE ABLE TO REACH
THE SFC...IF NOT SNOW THEN RAIN. CIGS LIFT TO VFR BY AFTERNOON THEN
SCATTER AFTER 00Z SUN. NW WINDS THRU THE PERIOD. BIGGEST GUST
POTENTIAL IS IN THE EVENING WITH INCREASING COLD AIR ADVECTION
PROMOTING MIXING.

ELSEWHERE...MOSTLY VFR CIGS TONIGHT WITH NO VSBY RESTRICTIONS
ANTICIPATED. GUIDANCE INDICATES SOME POSSIBILITY OF MVFR CIG
DEVELOPING WITH PRECIP JUST BEFORE DAYBREAK OVER THE ERN PIEDMONT
THOUGH CONFIDENCE IS LOW THAT THAT WOULD HAPPEN. CIGS HOWEVER LIKELY
TO LOWER WITH INCREASING DEEP MOISTURE BY THE EARLY DAYTIME HOURS.
MVFR CIGS WILL ACCOMPANY PRECIP IN THE LATE MORNING WEST TO MIDDAY
EAST. PRECIP TYPE WILL SOMEWHAT DEPEND ON SFC TEMP THOUGH SNOW
SHOULD BE ABLE TO AT LEAST MIX IN AT ALL THE SITES. CHC TOO LOW TO
MENTION AT KAND BUT IS INCLUDED ELSEWHERE. RETURN TO VFR BY LATE
AFTN WITH GUSTS POSSIBLE FROM MIDDAY THROUGH THE END OF THE PERIOD
AS COLD ADVECTION MAINTAINS DEEPLY MIXED SFC LAYER.

OUTLOOK...MOISTURE AND SOME RESTRICTIONS WILL REMAIN ALONG THE TN
BORDER THROUGH EARLY SUNDAY. ELSEWHERE...CONDITIONS WILL GENERALLY
REMAIN DRY WITH VFR CONDITIONS. HIGH PRESSURE BUILDS OVER THE REGION
EARLY NEXT WEEK.

CONFIDENCE TABLE...

09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 94% MED 75% HIGH 95% HIGH 100%
KGSP HIGH 91% LOW 55% HIGH 100% HIGH 100%
KAVL HIGH 98% MED 77% HIGH 100% HIGH 100%
KHKY HIGH 97% MED 76% HIGH 100% HIGH 100%
KGMU HIGH 94% LOW 54% HIGH 100% HIGH 100%
KAND HIGH 91% LOW 53% HIGH 100% HIGH 100%

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

$$
SYNOPSIS...SBK
NEAR TERM...WIMBERLEY
SHORT TERM...JDL
LONG TERM...SBK
AVIATION...WIMBERLEY
FIRE WEATHER...GSP

AREA FORECAST DISCUSSION

NWS NASHVILLE TN

928 PM CST SUN FEB 17 2013

.UPDATE...
ONGOING FORECAST LARGELY IN LINE AT THIS TIME. WEAK SFC HIGH
TOWARD TYS WILL CONTINUE TO SLOWLY PUSH EAST OVERNIGHT...ALLOWING
GRADIENT TO TIGHTEN. THIS SMALL KICK IN WIND ALONG WITH SOME HIGH
CLOUDS SPREADING OVER SHOULD KEEP TEMPERATURES FROM REALLY
BOTTOMING OUT. WILL HOWEVER KNOCK DOWN A FEW DEGREES PLATEAU WHERE
IT HAS REALLY COOLED OVER LAST FEW HOURS.

LATEST AVAILABLE DATA STILL PEGGING TOMORROW NIGHT FOR MAIN BRUNT
WITH INCOMING COLD FRONT. WINDS AHEAD DURING THE AFTERNOON MAY
GUST 35-40MPH BUT WILL HOLD OFF ON AN ADVISORY FOR NOW.

.PREV DISCUSSION... /ISSUED 537 PM CST SUN FEB 17 2013/

UPDATE...FOR 00Z AVIATION FORECAST

AVIATION...
GOOD WARM ADVECTION THROUGH THE 6K-10K LAYER AS EVIDENT BY BROKEN
ALTOCU AND LATEST RUC RUN.

VERY TIGHT GRADIENT ACROSS THE TENNESSEE VALLEY ON MONDAY SO AM
EXPECTING WIND GUSTS ON THE ORDER OF 30 KNOTS OUT OF THE SOUTH WITH
SUSTAINED WINDS AROUND 15 TO 18 KNOTS AT TIMES. LATEST SREF RUN
HOLDS PRECIP TO OUR WEST THROUGH ABOUT 00Z TOMORROW...WITH
SHOWERS/TSTMS PUSHING EAST OF TENNESSEE RIVER IN EARNEST DURING THE
EARLY EVENING AND OVERNIGHT MONDAY NIGHT.

I KEPT VFR CONDITIONS FOR NEXT 24 HOURS WITH ONLY A SMALL POP
CHANCE AT CLARKSVILLE`S TERMINAL AFTER 21Z.

BOYD

PREV DISCUSSION... /ISSUED 318 PM CST SUN FEB 17 2013/

DISCUSSION...
OTHER THAN A SMALL PESKY AREA OF SCT/BKN CLOUDS OVER WESTERN HALF
OF THE AREA...IT HAS BEEN A DECENT DAY ACROSS MID TN WITH TEMPS UP
5 TO 15 DEGREES COMPARED TO YESTERDAY...THOUGH STILL BELOW
AVERAGE. SKIES SHOULD BE MAINLY CLEAR TONIGHT BUT MIN TEMPS WON/T
BE A LOW AS THEY WERE TODAY BECAUSE THE SFC RIDGE WILL SLIDE EAST
AND ALLOW A LIGHT SOUTH WIND TO DEVELOP.

MAIN FORECAST CHALLENGES FOR THE WEEK AHEAD REVOLVE AROUND TWO
UPCOMING H5 LOWS...ONE EARLY IN THE WEEK...AND THE OTHER LATE IN
THE WEEK. BOTH SYSTEMS REMAIN ON THE SCHEDULE THAT WE HAVE
ADVERTISED FOR DAYS...NAMELY MONDAY NIGHT AND THURSDAY.

THE FIRST SYSTEM WAS DEVELOPING OVER THE ROCKIES TODAY AND WILL
STRENGTHEN AS IT MOVES TOWARD THE GREAT LAKES BY TUESDAY. A PRETTY
SHARP PRESSURE GRADIENT WILL DEVELOP ACROSS OUR REGION ON MONDAY
AS THE SFC LOW PASSES TO OUR NORTHWEST...AND WINDS MAY APPROACH
ADVISORY CRITERIA IN THE AFTERNOON. ALTHOUGH THESE WARM BREEZES
WILL INCREASE LOW LEVEL MOISTURE DURING THE DAY...EXPECT A
MARGINAL FIRE WEATHER DANGER DAY ON MONDAY WITH DECENT WINDS AND
RELATIVELY LOW RH. THE STORM MAY BE CLOSE ENOUGH FOR SOME SHOWERS
IN THE WEST MONDAY AFTERNOON BUT THE BULK OF THE RAIN SHOULD FALL
MONDAY NIGHT. QPF SHOULD BE LESS THAN ONE INCH AS STORM MOVES AT
A DECENT CLIP ACROSS THE REGION. A COLD FRONT WILL SWEEP INTO THE
AREA VERY EARLY TUESDAY WITH RAPID DRYING AREAWIDE.

DESPITE A BRIEF PERIOD OF FAIR WEATHER CENTERED ON WEDNESDAY
THANKS TO A WEAK H5 RIDGE...THE NEXT STORM SYSTEM WILL ALREADY BE
DEVELOPING OVER THE SW U.S. MOISTURE...WINDS AND CHANCES FOR
PRECIP WILL INCREASE THURSDAY INTO THURSDAY NIGHT. AIRMASS WILL
START OF PRETTY COOL THURSDAY MORNING BUT DON/T BELIEVE PRECIP
WILL ARRIVE IN TIME FOR ANY OF IT TO BE FREEZING/FROZEN. THERE/S
A LITTLE BETTER CHANCE OF THUNDER WITH THIS SECOND SYSTEM BUT BEST
INSTABILITY SHOULD REMAIN WELL SOUTH OF THE MID STATE AS WILL ANY
CHANCE FOR SEVERE WEATHER.

WHILE OUR SECOND STORM SYSTEM MEANDERS OVER THE NORTH CENTRAL U.S.
FRI AND SAT...THE SOUTHERN BRANCH OF THE JET WILL BE ACTIVE ACROSS
THE SOUTHERN HALF OF THE U.S. A COUPLE QUICK MOVING SHORT WAVES
ARE POSSIBLE DURING THIS PERIOD BUT NOT ENOUGH CONFIDENCE TO
INCLUDE PRECIP AT THIS TIME. HOWEVER...GFS AND ECMWF AGREE THAT
YET ANOTHER LARGE H5 LOW WILL DEVELOP OVER THE SW U.S. NEXT
WEEKEND...AND POSSIBLY IMPACT MID TN WEATHER AROUND MONDAY FEB
25.

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

AREA FORECAST DISCUSSION

NWS NASHVILLE TN

537 PM CST SUN FEB 17 2013

.UPDATE...FOR 00Z AVIATION FORECAST

.AVIATION...
GOOD WARM ADVECTION THROUGH THE 6K-10K LAYER AS EVIDENT BY BROKEN
ALTOCU AND LATEST RUC RUN.

I KEPT VFR CONDITIONS FOR NEXT 24 HOURS WITH ONLY A SMALL POP
CHANCE AT CLARKSVILLE`S TERMINAL AFTER 21Z.

BOYD
&&

.PREV DISCUSSION... /ISSUED 318 PM CST SUN FEB 17 2013/

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

AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

1139 PM EST FRI FEB 15 2013

.SYNOPSIS...
A COLD FRONT MOVES EAST OF THE REGION OVERNIGHT...FOLLOWED BY A
STRONGER ARCTIC COLD FRONT SATURDAY NIGHT. MEANWHILE...AN AREA OF
LOW PRESSURE WILL FORM ALONG THE FIRST BOUNDARY AND MOVE OFF THE
CAROLINA COAST BEFORE TURNING NORTH LATER SATURDAY. HIGH PRESSURE
ARRIVES SUNDAY NIGHT BEFORE ANOTHER COLD FRONT ENTERS THE
APPALACHIANS LATE MONDAY NIGHT.
&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 950 PM EST FRIDAY...

BASED ON ADDED SNOWFALL REPORTS OF AROUND 3 INCHES IN TAZEWELL CTY
ALONG WITH DEVELOPING SLICK ROAD CONDITIONS...WENT AHEAD WITH A
WINTER WEATHER ADVISORY THROUGH 4 AM FOR TAZEWELL...MERCER AND
BLAND CTYS WHERE COULD SEE UP TO 4 INCHES OF SNOW BEFORE THINGS
TAPER OFF TO FLURRIES.

AS OF 845 PM EST FRIDAY...

PERSISTENT BAND OF SNOW REMAINS ACROSS FAR SW VA INTO SE WVA ALONG
THE LEADING EDGE OF THE DEEPENING 5H TROF TO THE WEST AND UNDER A
WEAK SHORTWAVE AHEAD OF THE MAIN UPPER COLD POOL. WARM SURFACES
FROM EARLIER TODAY HAVE APPARENTLY LIMITED ACCUMULATIONS DESPITE
SEVERAL HOURS OF DECENT SNOWFALL WITH TOTALS OF 1-2 INCHES REPORTED
MAINLY ON GRASSY SURFACES. SINCE APPEARS WILL BE TAPERING SHORTLY
WONT HOIST AN ADVISORY YET UNLESS HEAVIER BANDS PERSIST LONGER.
OTRW LATEST RAP AND LOCAL RNK WRF SHOW THIS BAND OF SNOW FINALLY
WEAKENING BEFORE MIDNIGHT AS ENERGY SHIFTS EAST AND THE 85H FLOW
TURNS MORE NNW. THUS KEEPING IN A FEW MORE HOURS OF CAT/LIKELY
POPS THERE BEFORE DIMINISHING AFTER MIDNIGHT. OTRW COLD FRONT NOW
ENTERING THE PIEDMONT WITH A FEW RAIN SHOWER BANDS ALONG IT OVER
THE SE IN STRONG SW FLOW ALOFT DEPICTED OFF EVENING SOUNDINGS.
EXPECT THIS RAINFALL TO AFFECT AREAS MAINLY EAST OF THE BLUE RIDGE
BEFORE THE FRONT FINALLY GETS FAR ENOUGH EAST OF THE REGION TO
SUPPORT A LITTLE BETTER DOWNSLOPING IN THE NEXT FEW HOURS. THUS
THINKING WILL SEE A LULL IN PRECIP FOR THE MOST PART DURING THE
EARLY MORNING HOURS WITH THE FRONT TO THE SE...ONLY WEAK UPSLOPE
OVER THE WEST...AND LITTLE SUPPORT ALOFT AS WE SLIDE IN BETWEEN
UPPER IMPULSES LATER TONIGHT. THIS IN LINE WITH POPS FROM EARLIER
FOR AFTER MIDNIGHT SO ONLY TWEAKED POP COVERAGE LATER ON. HAVE
SEEN LITTLE SNOW IN THE ADVISORY AREA BUT LEAVING HEADLINES AS IS
FOR NOW. TEMPS SLOW TO FALL OUT EAST BUT WILL GET INTO BETTER COLD
ADVECTION SHORTLY WITH THE LAV MOS LOOKING TOO WARM MOST SPOTS
OVERNIGHT.

PREVIOUS DISCUSSION...

A MORE POTENT UPPER LEVEL WAVE PUSHING INTO THE CENTRAL PLAINS THIS
AFTERNOON WILL MOVE ACROSS THE CAROLINAS ON SATURDAY...WHICH SPINS
UP A SFC LOW OFF THE NC COAST. MODELS SHOW GOOD 700MB FRONTOGENESIS
FORMING IN ADVANCE OF THIS SYSTEM...SUGGESTING HEAVY BANDS OF PRECIP
WILL DEVELOP ACROSS NC AND IN THE EASTERN PORTION OF OUR FORECAST
AREA. FORECAST SOUNDINGS SUGGEST TEMPS ALOFT WILL SUPPORT SNOW...OR
A RAIN/SNOW MIX. DYNAMIC COOLING WITH THIS STRONG SYSTEM SHOULD KEEP
MOST OF THE PRECIP IN THE FORM OF SNOW. SOME FACTORS THAT COULD
LIMIT SNOW ACCUMULATION ARE THE WARM GROUND TEMPS AND THE FACT OUR
AREA WILL BE ON THE NORTHWEST SIDE OF THE BEST LIFT. IN FACT...THE
GFS IS AN OUTLIER WITH THE WESTERN EXTENT OF THE PRCIP SHIELD...AND
A SLIGHTLY MORE EASTERN TRACK...AS SHOWN BY THE 12Z ECMWF KEEPS THE
HEAVIEST AMOUNTS OUT OF FORECAST AREA.

STILL...WILL ISSUE WINTER WEATHER ADVISORIES FOR THE NC MOUNTAINS
FOR NEAR ADVISORY CRITERIA IN HIGHER ELEVATIONS...BUT LESS AMOUNTS
TO THE EAST AND NO HEADLINES.

AS THE SFC LOW DEEPENS...WINDS WILL INCREASE FROM THE NORTHWEST AND
UPSLOPE SNOW SHOWERS WILL AGAIN DEVELOP ACROSS SOUTHEAST WEST
VIRGINIA.

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 408 PM EST FRIDAY...

LOW PRESSURE MOVING ALONG TONIGHT`S COLD FRONT SATURDAY WILL BE
MOVING FAR ENOUGH AWAY FROM OUR AREA TO PULL ITS PRECIP SHIELD
JUST OUT OF OUR EXTREME EASTERN COUNTIES EARLY SATURDAY NIGHT.
DEPENDING UPON HOW DEEP THIS LOW TURNS OUT TO BE...SNOW MAY HOLD
ALONG THESE COUNTIES A LITTLE LONGER THAN CURRENTLY FORECAST.
ARCTIC BOUNDARY ARRIVING WILL GENERATE UPSLOPE SNOW SHOWERS AGAIN
SATURDAY NIGHT...WITH ENOUGH MOISTURE TO POSSIBLY DELIVER SOME
SNOW SHOWERS INTO THE NEW RIVER VALLEY. AS AN UPPER LEVEL
DISTURBANCE LEAVES AFTER MIDNIGHT INTO SUNDAY MORNING...MOISTURE
DRIES OUT RAPIDLY AND SNOW SHOWERS WILL BE MORE CONFINED TO SE
WEST VA. EXPECTING THE GREATEST COVERAGE OF SNOW SHOWERS AROUND
6Z/1AM SUNDAY. UP TO 4" MAY FALL ACROSS WESTERN GREENBRIER WITH AN
INCH OR TWO DOWN INTO BLF AND SIMILAR LOCATIONS ABOVE 2500 FEET.
WIND DIRECTION SHOULD ALSO DELIVER SOME SNOW BANDS INTO NW NC
WHERE AN INCH OR LESS IS EXPECTED BUT 2" ABOVE 3500 FEET. AS
CLOUDS ARE REMOVED AND BETTER MIXING OCCURS ADVISORY CRITERIA WIND
GUSTS ARE LIKELY ASHE/WATAUGA/GRAYSON AND A HIGH WIND WATCH MAY
NEED TO BE CONSIDERED. AGAIN...MOS TEMPS LOOK TOO WARM WITH A
SHALLOW ARCTIC AIRMASS SO USED SOME OF THE COLDER VALUES. SINGLE
DIGITS DEWPOINTS AND RELAXING OF WIND WILL ALLOW DECOUPLING
AND WIDESPREAD LOWS IN THE MIDDLE TEENS SUNDAY NIGHT. UPPER
TROUGH LEAVES MONDAY WITH QUICK WAA...BUT A LOW MOVING INTO THE
GREAT LAKES WILL DRAG A FRONT AND PRECIP ACROSS THE REGION LATE
MONDAY NIGHT...WITH EVAP COOLING LIKELY PRODUCING A QUICK SHOT OF
SLEET AND MAYBE SOME FREEZING RAIN ACROSS GREENBRIER INITIALLY.

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 350 PM EST FRIDAY...

HIGH PRESSURE DRIFTS OFF THE SOUTHEAST COAST ALLOWING A COLD FRONT
TO PASS OVER THE REGION TUESDAY. A WINTRY MIX OF RAIN/SNOW/SLEET MAY
STILL BE FALLING ACROSS THE GREENBRIER VALLEY AND ALLEGHANY
HIGHLANDS TUESDAY MORNING. TEMPERATURES WARM BY MID MORNING WITH ALL
PRECIPITATION FALLING AS RAIN. RAIN EXITS QUICKLY BY THE EVENING RUSH
HOUR WITH WINDS INCREASING FROM THE WEST. WE WILL SEE CLEARING
CONDITIONS FROM EAST TO WEST OVERNIGHT WITH SOME LINGERING
CLOUDS/UPSLOPE SNOW SHOWERS INTO EARLY WEDNESDAY MORNING. TRAJECTORIES
ARE NOT FAVORABLE FOR SIGNIFICANT UPSLOPE ACCUMULATIONS. MOISTURE
COULD BE SHALLOW BY THE TIME THE COLDEST AIR ARRIVES TO JUST HAVE
SPOTTY FREEZING DRIZZLE/SCATTERED FLURRIES.

STRONG SOUTHWEST FLOW AHEAD OF THE FRONT MAY CREATE SOME WIND
PROBLEMS ACROSS THE BLUEFIELD/RICHLANDS AREA TUESDAY MORNING. AS THE
JET TRANSFERS EAST OF THE APPALACHIANS...STRONG WINDS MIXING TO THE
SURFACE COULD PRODUCE ADVISORY GUSTS FOR THE REST OF THE AREA. WILL
CONTINUE TO HIGHLIGHT IN THE HWO. STRONG AND GUSTY WINDS WILL ALSO
FOLLOW THE FRONT WITH ANY ADVISORY GUSTS REMAINING ALONG THE HIGHER
RIDGES ALONG THE BLUE RIDGE.

HIGH PRESSURE WILL MOVE OVER THE REGION WEDNESDAY AFTERNOON WITH
BREEZY CONDITIONS RELAXING BY THE EVENING. A WARM FRONT IS EXPECTED
TO OVERRUN THIS SURFACE HIGH PRESSURE ON THURSDAY. LIGHT
PRECIPITATION COULD START FALLING AS EARLY AS THURSDAY AFTERNOON (12Z
GFS) OR START EARLY FRIDAY MORNING (12Z ECMWF). AS PRECIPITATION
FALLS INTO THIS RIDGE...AN INSITU WEDGE WILL DEVELOP WITH A
PERSISTENT EASTERLY FLOW THROUGH THE DAY FRIDAY. DESPITE THE TIMING
DIFFERENCES...EVAPORATIVE COOLING IN BOTH MODELS OVERNIGHT SUPPORT
FROZEN PRECIPITATION THURSDAY NIGHT INTO FRIDAY. GFS FORECAST
SOUNDING SUGGESTING FREEZING RAIN. WITH UNCERTAINTY LOOMING LARGE
THIS FAR OUT...WILL KEEP GRIDS SIMPLE WITH RAIN/SNOW. GFS IS ALSO
BREAKING THE WEDGE QUICKLY FRIDAY MORNING. KEPT THE WEDGE IN LONGER
AND COULD SEE IT BREAKING FRIDAY NIGHT VIA PRESSURE FALLS OVER THE
OHIO VALLEY PER THE ECMWF.

TEMPERATURES WILL HOVER AROUND NORMAL ON TUESDAY. CHILLY HIGH
PRESSURE WILL TREND AFTERNOON TEMPERATURES BELOW NORMAL WEDNESDAY
AND THURSDAY. TEMPERATURES WILL CONTINUE TO TREND COLDER FRIDAY WITH
A WET COLD AIR DAMMING EVENT EXPECTED.

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1130 PM EST FRIDAY...

COLD FRONT NOW CROSSING INTO THE PIEDMONT WITH A LINGERING BAND OF
MOSTLY RAIN SHOWERS ALONG AND BEHIND THE BOUNDARY MAINLY FROM KLYH
TO KMTV ATTM. LOCAL WRF CONTINUES TO STILL HAVE THE BEST HANDLE
SO WILL FOLLOW CLOSELY AND PUSH RAIN A BIT FARTHER EAST INTO
KLYH/KDAN FOR A FEW HOURS OVERNIGHT SINCE GOOD DOWNSLOPE IS
LAGGING THE FRONT. OTRW WILL HAVE PERIODIC MVFR TO IFR AT
KBLF WHERE SNOW HAS FINALLY TAPERED OFF...AND MOSTLY MVFR AT
KLWB/KBCB AS EXPECTING UPSLOPE TO KEEP LOW CIGS ALONG THE WESTERN
SLOPES WITH SOME OF THE COLD ADVECTION STRATO-CU SPILLING EAST
TOWARD THE BLUE RIDGE OVERNIGHT. MAY CONTINUE TO INCLUDE A VFR
MENTION OF A -SHSN OVERNIGHT IN THE WEST BUT LOOKING QUITE
ISOLATED UNTIL LATE AT BEST WHEN BETTER UPSLOPE KICKS IN. ELSW
WILL MAINTAIN VFR OUT EAST PENDING JUST HOW FAR THE PRECIP GETS IN
THE NEXT FEW HOURS BUT EVEN THEN APPEARS CIGS AOA 4K FT. KLWB AND
KBLF WILL TRANSITION TO AN UPSLOPING PCPN -SHSN EVENT BY DAYBREAK
AND CONTINUE OFF AND ON THROUGH SATURDAY. STILL LOOKING FOR MVFR
CIGS/VSBYS AND EXPECT -SHSN TO BE LIGHT AS BEST MOISTURE WILL BE
TO THE EAST WITH THE OFFSHORE LOW TAKING SHAPE.

KDAN/KLYH IS INTERESTING FOR THE LATTER PORTION OF THE TAF
PERIOD. LIFT DEVELOPING ON THE BACK SIDE OF THE DEEPENING LOW
SLIDING OFF THE COAST WILL BEGIN TO DEVELOP A PRECIPITATION
SHIELD TO THE WEST. IT CURRENTLY LOOKS LIKE KDAN WILL BE ON THE
EDGE OF THIS AND WILL INTRO A PERIOD OF MVFR CIGS IN AFTER 12Z
ALONG WITH SOME PCPN THAT MAY BE ALL SNOW DURING THE MORNING. ALSO
POTENTIAL FOR A NARROW RIBBON OF SNOW OR SNOW SHOWERS TO DEVELOP
NEAR HIGHWAY 29 SATURDAY AFTERNOON WHICH COULD BRING LOCALIZED
MVFR/IFR IN A SWATH SO INCLUDING A BIT MORE SNOW MENTION AT BOTH
KDAN/KLYH AGAIN SATURDAY AFTERNOON BUT LOW CONFIDENCE AT THIS
POINT.

LOW LEVEL WINDS DO NOT RAMP UP UNTIL LATER IN THE DAY SATURDAY IN
RESPONSE TO DEEPENING OF COASTAL LOW SO DO NOT EXPECT SIGNIFICANT
WINDS TO HAMPER AVIATION INTERESTS UNTIL LATE SATURDAY OR MORESO
SATURDAY NIGHT.

EXTENDED AVIATION DISCUSSION...
REASONING THROUGH THE EXTENDED PORTION STILL APPLIES AS PER PREVIOUS
DISCUSSION:

HIGH PRESSURE AND VFR CONDITIONS WILL RETURN TO THE MOUNTAINS BY
SUNDAY ALTHOUGH NW WINDS WILL BE QUITE STRONG AND GUSTY. GOOD
FLYING WEATHER SHOULD PREVAIL UNTIL TUESDAY...WHEN A NEW COLD
FRONT COULD BRING SHOWERS WITH GUSTY WINDS ALONG WITH MVFR/IFR
CEILINGS. VFR QUICKLY RETURNS ON WEDNESDAY WITH HIGH PRESSURE
FOLLOWING THE FRONT.

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST SATURDAY FOR VAZ007-010.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST SUNDAY FOR NCZ001-018.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST SATURDAY FOR WVZ042.

$$
SYNOPSIS...AMS/KM
NEAR TERM...AMS/JH/PH
SHORT TERM...KM
LONG TERM...RCS
AVIATION...AMS/JH/NF

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...VISIT

WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

602 PM CST SUN FEB 17 2013

.SHORT TERM...TONIGHT INTO MONDAY
602 PM CST SUN FEB 17 2013

THE FORECAST...PARTICULARLY FOR MONDAY MORNING HAS BECOME A BIT
MORE UNCERTAIN. DOING SOME ANALYSIS OF THE 17.12Z/18Z NAM/GFS
MODELS FOR 00HR AND 03HR FORECASTS...THERE ARE SOME SERIOUS ISSUES
IN THE BOUNDARY LAYER:

1. NAM SAYS THERE IS SNOWPACK ACROSS NORTHERN AND EASTERN NEBRASKA
AND DOWN INTO WESTERN MISSOURI. ACROSS THIS SNOWPACK...THE MODEL
JUMPS DEWPOINTS INTO THE LOW 40S. THERE IS NONE AND DEWPOINTS ARE
IN THE TEENS AND 20S.
2. BOTH THE NAM/GFS DEPICT NEAR SATURATED CONDITIONS AT 925MB
ACROSS EASTERN SOUTH DAKOTA AND SOUTHERN MN...SUGGESTING EXTENSIVE
LOW CLOUDS. REALITY...NO LOW CLOUDS.
3. BOTH THE NAM/GFS 925MB RH FIELD WOULD SUGGEST LOW CLOUDS IN
DEEP SOUTH TEXAS INTO EASTERN MEXICO...WHICH IS THE MOISTURE
COMING UP FOR TOMORROW. REALITY...NO LOW CLOUDS AND MOSTLY JUST A
4000-6000 FT CEILING BASES.

AS SUCH...DO NOT HAVE MUCH CONFIDENCE IN THEM HANDLING BOUNDARY
LAYER MOISTURE FOR MONDAY. BOTH MODELS USE THE LOW LEVEL MOISTURE
IN EASTERN SOUTH DAKOTA/SOUTHERN MN AND THAT COMING UP FROM DEEP
SOUTH TEXAS TO HELP SUGGEST THE LOW CLOUDS OVER THE AREA MONDAY
MORNING.

17.22Z RAP/HRRR AND 17.12Z NCEP HIRES-ARW ARE DOING A MUCH BETTER
JOB...THOUGH EVEN THE HIRES-ARW SUGGESTS THERE SHOULD BE LOW
CLOUDS OVER EAU CLAIRE WHEN THERE IS NONE. STILL...NONE OF THEM
HAVE LOW CLOUDS OVER EASTERN SOUTH DAKOTA NOR BRING UP LOW CLOUDS
FROM DEEP SOUTH TEXAS AS FAST. THIS MODEL GROUP WOULD SAY ANY LOW
CLOUDS ARE ALL POST-FRONTAL. THUS...HAVE A LOT OF DOUBT ABOUT THE
DRIZZLE OCCURRING ON MONDAY. A MORE LIKELY SCENARIO SEEMS TO BE A
MID-LEVEL FRONTOGENETIC BAND OF SNOW DEVELOPING BEHIND THE COLD
FRONT NEAR MID-DAY...EXTENDING SOUTHWEST TO NORTHEAST ACROSS THE
CENTRAL PORTION OF THE FORECAST AREA. THIS BAND THEN PROPAGATES
SOUTH. DEPENDING ON HOW QUICK THE LOW LEVELS COOL...SOME OF THIS
SNOW COULD MELT INITIALLY. AFTER THE FRONTOGENETIC BAND OF SNOW
PASSES AND COLDER AIR COMES IN...THE LOW CLOUDS EVENTUALLY START
PRODUCING FLURRIES AS THEY INTERSECT THE DENDRITIC GROWTH ZONE.
THIS SEEMS MOST LIKELY TO OCCUR OVER THE NORTHWEST HALF OF THE
FORECAST AREA.

AFTER A LOOK AT 00Z SOUNDING DATA AND ADDITIONAL RAP AND PERHAPS
NAM DATA...WILL CONSIDER MAKING ADJUSTMENTS TO THE PRECIPITATION
TYPES AND CHANCES IN GENERAL FOR MONDAY.

IN SUMMARY...THE WINTRY MIX CONCERN FOR MONDAY LOOKS TO BE
DECREASING.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
257 PM CST SUN FEB 17 2013

THE MAIN STORY FROM MID WEEK INTO NEXT WEEKEND IS WITH THE STORM
SYSTEM THAT WILL BRING ACCUMULATING SNOW INTO THE REGION THURSDAY
INTO FRIDAY. THE MODEL TRENDS HAVE BEEN FAIRLY CONSISTENT WITH
SHOWING A WEAKENING LOW PRESSURE SYSTEM TRACKING FROM KANSAS INTO
IOWA AND NORTHERN WISCONSIN. THE 17.12Z ECMWF IS A TAD FASTER THAN
THE 17.12Z GFS/GEM...BUT THE OVERALL MESSAGE APPEARS TO BE THE
SAME. THE MAIN FORCING COMES IN THE AFTERNOON TO OVERNIGHT HOURS
ON THURSDAY AS THE MID LEVEL TROUGH AND PV ANOMALY PROPAGATE
ALMOST DUE NORTH FROM WESTERN IOWA INTO WESTERN MINNESOTA. THIS
SHOULD YIELD ABOUT A 6-HOUR PERIOD WHERE A BAND OF MODERATE
SNOW WILL FALL BEFORE TAPERING OFF AS THE FORCING BECOMES MUCH
MORE BROAD. STILL...IT SHOULD BE A LONG DURATION LIGHT TO MODERATE
SNOW THAT WILL LIKELY NEED SOME SORT OF HEADLINES DOWN THE ROAD.

AFTER THIS SYSTEM MOVES THROUGH IT LOOKS LIKE ANOTHER MAINLY QUIET
PERIOD FOR NEXT WEEKEND. LEFT SOME SMALL CHANCES FOR SNOW ON
SUNDAY AS THE 17.00Z ECMWF WAS FASTER WITH BRINGING THE NEXT
SYSTEM IN...BUT THE TREND APPEARS TO BE GOING TOWARD THE SLOWER
GFS WHICH WOULD NOT BRING THE NEXT SYSTEM IN UNTIL MONDAY. THIS
COULD BE ANOTHER SIGNIFICANT STORM FOR THE REGION...BUT THERE ARE
A LOT OF DETAILS THAT NEED TO BE WORKED OUT FOR THAT SYSTEM AND
ITS TRACK.

.AVIATION...TONIGHT AND MONDAY
602 PM CST SUN FEB 17 2013

A LOT GOING ON WITH THIS AVIATION FORECAST.

OVERALL...WINDS ARE THE BIG ISSUE. THE PRESSURE GRADIENT HAS
TIGHTENED UP THIS AFTERNOON AHEAD OF LOW PRESSURE IN THE DAKOTAS.
THIS GRADIENT REMAINS TIGHT MUCH OF THE NIGHT...AND KRST BEING A
HIGHER ELEVATION SITE...THINKING THAT 15-20 KT WINDS WITH GUSTS TO
25 KT WILL HOLD NEARLY STEADY UNTIL ABOUT 10Z. THIS IS WHEN A LOW
LEVEL JET OVER THE TAF SITES...WITH SOUTH SPEEDS AROUND 45 KT AT
1500-2000 FT PUSHES OFF TO THE EAST. SINCE THE SURFACE WINDS STAY
STRONG...HAVE REMOVED THE LOW LEVEL WIND SHEAR FOR KRST. SHOULD
THE GUSTS DROP OFF...LOW LEVEL WIND SHEAR MAY BE NEEDED. AT KLSE...
LIGHTER SOUTHEAST WINDS FROM BEING IN THE VALLEY COMBINED WITH
THIS LOW LEVEL JET RESULTS IN MAINTAINING LOW LEVEL WIND SHEAR
UNTIL 11Z. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PUSH
THROUGH THE TAF SITES BETWEEN 15-19Z...SWINGING WINDS AROUND TO
THE NORTHWEST. AS COLD AIR RUSHES IN AND PRESSURES RISE...EXPECT
THE WINDS TO INCREASE AND GUST FOR THE AFTERNOON. GUSTS OF 20-30
KT ARE POSSIBLE...STRONGEST AGAIN AT THE HIGHER ELEVATION KRST
SITE.

THE GFS AND NAM MODELS HAVE BEEN PERFORMING BADLY WITH RESPECT TO
HANDLING MOISTURE IN THE LOWEST COUPLE THOUSAND FEET THIS
AFTERNOON. SEE THE SHORT TERM SECTION ABOVE FOR MORE DETAILS. THE
00Z TAFS RELY MORE ON THE RAP/HRRR/NCEP HIRES-ARW RUNS WHICH ARE
DOING A MUCH BETTER JOB. THESE MODELS ALL SUGGEST THAT LOW CLOUD
POTENTIAL IS MUCH LESS...UNTIL THE COLD FRONT COMES THROUGH. EVEN
THEN...THE CEILINGS THAT COME IN THE WAKE OF THE FRONT ARE
MVFR...REPRESENTATIVE TOO OF WHAT IS UPSTREAM IN WESTERN NORTH
DAKOTA.

REGARDING PRECIPITATION AND REDUCTION TO VISIBILITY...CONFIDENCE
OF BOTH ARE REALLY LOW. THERE SHOULD BE A BAND OF SNOW THAT FORMS
IN THE WAKE OF THE COLD FRONT...LIKELY FORMING EAST OF KRST AND PERHAPS
IMPACTING KLSE. INCLUDING A BRIEF PERIOD OF MVFR VISIBILITY SINCE
KLSE LOOKS TO BE ON THE EDGE. OTHERWISE...SOME FLURRIES SHOULD
OCCUR FROM THE LOW CLOUDS ACCOMPANYING THE COLDER AIR.

.ARX WATCHES/WARNINGS/ADVISORIES...
257 PM CST SUN FEB 17 2013

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...AJ
LONG TERM...HALBACH
AVIATION...AJ

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

327 PM CST SAT FEB 16 2013

.SHORT TERM...THROUGH TUESDAY NIGHT
326 PM CST SAT FEB 16 2013

MUCH OF THE TIME TODAY WAS SPENT WORKING ON MONDAY INTO TUESDAY.
IMPACTS LOOK TO BE MINIMAL AS MAIN PRECIPITATION REGION LOOKS TO
ADVECT IN JUST EAST OF THE FORECAST AREA.

CLOUDS HAVE BEEN A TOUGH FORECAST AS OF LATE...AND TONIGHT THEY
COULD HAVE A HUGE IMPACT ON LOW TEMPERATURES. CURRENT GOES
SATELLITE IMAGERY SHOWING CLOUDS EXPANDING IN WRN MN WEST OF THE
SURFACE RIDGE AXIS FROM KINL TO KALO. MAINLY CUMULUS FIELDS
ARE AFFECTING THE FORECAST AREA WITH THOSE EXPECTED TO DISSIPATE
BY LATE AFTERNOON. SURFACE OBSERVATIONS SHOWING A STATIONARY FRONT
LOCATED FROM ABOUT KFSD-KDSM WITH WARM AIR TO THE SOUTHWEST AND
CONVERGENT FLOW INTO NE IA.

GOES WATER VAPOR SHOWING THE MONDAY S/WV WELL NOW COMING ONTO THE
WEST COAST WITH THE NRN ENERGY OVER BRITISH COLUMBIA AND THE
16.19Z RAP INDICATING A TROPOPAUSE FOLD TO 400MB INTO THE OR
COAST REPRESENTING THE SRN ENERGY THAT IS FORECAST TO DIG INTO THE
CENTRAL U.S. KUIL WASHINGTON RAOB HAD A 150M/12HR HEIGHT FALL THIS
MORNING AHEAD OF THIS POTENT SHORTWAVE TROUGH.

HAVE LOWERED THE LOW TONIGHT ACROSS CENTRAL WI AS THE SURFACE
RIDGE WILL BE RIGHT OVERHEAD MOST OF THE NIGHT AND CLOUDS ARE
FORECAST TO REMAIN MINIMAL. HAVE DROPPED LOWS 5-7F THERE TONIGHT
FROM PREVIOUS FORECAST. CLOUDS ARE TOUGH THOUGH AND AM THINKING
TWO AREAS COULD DEVELOP STRATUS...CURRENT HEAVY CUMULUS AREA OVER
NRN WI AND CONVERGENT BOUNDARY ACROSS IA. THE NRN WI AREA COULD
EXPAND OVER NRN FORECAST AREA LATE AND CLOUDS WILL ALSO SPREAD IN
FROM THE SW. THUS...LOW CONFIDENCE IN FORECAST CLOUDS AND LOWS
TONIGHT...BUT FORECASTING THE CENTRAL FORECAST AREA TO REMAIN
MOSTLY CLEAR.

WARM ADVECTION TO KICK IN SUNDAY AND PEAK SUNDAY NIGHT WITH
WARMING OCCURRING INTO MONDAY WEATHER SYSTEM. 16.12Z MODEL
CONSENSUS IS TO STILL DEVELOP THE NRN CYCLONE THE MOST...NORTH OF
THE GREAT LAKES...WITH THE SRN ENERGY CAUSING WEAK CYCLOGENESIS
ALONG THE FRONTAL BOUNDARY AS IT PASSES TO THE SE OF THE FORECAST
AREA. SOME SPREAD STILL REMAINS IN THE GUIDANCE. THE 16.12Z NAM
REMAINS CONSISTENT WITH IT/S PREVIOUS RUNS OF THE DRY OUTLIER. THE
16.12Z CANADIAN GLOBAL GEM STILL INSISTS ON A WET 0.30 INCHES
AREA-WIDE WITH THIS SYSTEM /AND HIGHS IN THE 40S/. STILL PREFER THE
CONSISTENT ECMWF/GFS RUNS ON THE OUTCOME FOR THIS SYSTEM. IT
APPEARS THE MAIN MOISTURE AXIS WILL ONLY GRAZE THE ERN FORECAST
AREA FROM CENTRAL WI TO SWRN WI...A STEP EAST FROM PREVIOUS MODEL
RUNS. THIS SAME AREA WILL SEE THE DEEPEST SURFACE-BASED SATURATION
COME IN MONDAY MORNING /KOVS 0-2 KM/...WITH THE LAYER MORE SHALLOW
FURTHER TO THE NW /KEAU 1KM/. NW OF THE SURFACE WAVE...WOULD THINK
A BIT OF ENHANCEMENT IN THE DEFORMATION WILL OCCUR AND HAVE KEPT
HIGHEST PRECIPITATION CHANCES IN THAT SWRN-CENTRAL WI
AREA...TAPERING LOWER TO THE NORTHWEST.

IT APPEARS DEEP SATURATION TO COLDER THAN -10C TO GET ICE GROWTH WILL
BE TROUBLESOME/SPOTTY OR JUST PLAIN HARD TO FORECAST WITH THIS
SYSTEM. THE Q-G FORCING IS MODERATE ALOFT AND WEAKER IN THE LOW
LEVELS PROVIDING OVERALL A WEAK BUT PRESENT LIFT SIGNAL. BUT
REVIEWING MODEL SOUNDINGS FROM THE 16.09Z SREF AND 16.12Z NAM/GFS
THERE IS CONSISTENT STRUGGLES WITH SATURATION NOTED...AND THUS
HAVE GONE WITH A MAJORITY OF LIQUID IN THE FORECAST UNTIL THE COLD
FRONT MOVES IN LATER MONDAY WITH VERY STRONG COLD ADVECTION TO DRIVE
THE ICE PROCESS AND SNOW CONVERSION. THIS SATURATION STRUGGLE AWAY
FROM THE SURFACE WAVE IS ALSO WHY PRECIPITATION CHANCES ARENT
HIGHER FOR THIS FORECAST.

MONDAY MORNING WILL SEE THE MOISTURE INCREASE AND SURFACE TEMPERATURES
WARMING TO NEAR OR ABOVE FREEZING IN THE AFTERNOON. THIS WILL
CAUSE A FZDZ POSSIBILITY MAINLY IN THE MORNING IF THE LAYER CAN
PRECIPITATE...PROBABLY VERY LIGHT AMOUNTS AROUND 0.01-0.02 INCHES
TO PROVIDE A LIGHT GLAZE AFTER COMMUTE TIME. MANY AREAS SOUTH OF
I-90 WILL WARM TO ABOVE FREEZING BY MID-DAY...ESPECIALLY CLOSE TO
THE MOIST AXIS SO IMPACTS WOULD BE MINIMAL THERE...OR AT LEAST
SHORT LIVED. HAVE KEPT FZDZ STILL POSSIBLE FOR POINTS WITH AIR
TEMPERATURES OF 35F OR COLDER AS ROADS MAY STILL BE SLOWER TO
RECOVER TO ABOVE FREEZING.

THE NORTHERN AND WESTERN AREAS COULD SEE FZDZ PERIODICALLY MONDAY
THROUGH THE DAY...POSSIBLE MIXING WITH SNOW AS SATURATION OCCURS
IN A PATCHY WAY. THE COLD FRONT WILL SWEEP IN WITH VERY STRONG
COLD ADVECTION CONVERTING ALL LIGHT LIQUID PRECIPITATION TO SNOW.
WITH THE COLD ADVECTION STRONG...LAPSE RATES IN THE LOWEST 1 KM
ARE QUITE STEEP AND WILL PROMOTE WIND GUSTS IN THE 25 TO 35 MPH
RANGE LATE MONDAY AND OVERNIGHT. HAVE INCREASED THE WINDS WITH
THIS FORECAST BASED ON 16.12Z NAM/GFS BLEND.

OVERALL...COMFORT REMAINS LOW ON THIS SYSTEM /I HAVE MORE
CONFIDENCE IN THE THU-FRI SNOW/ BUT MY FEELING IS THAT THE IMPACTS
WILL BE MINOR. DO NOT FEEL A NEED FOR A HEADLINE ON THIS SYSTEM AS
THE LIQUID AMOUNTS LOOK TO BE PRETTY LIGHT. IN THE DEFORMATION
AREA TEMPERATURES WOULD BE WARMEST AND MAINLY RAIN WOULD FALL. BUT
THERE ARE SOME HINTS THAT UP TO A TENTH OF PRECIPITATION COULD
FALL MONDAY AWAY FROM THE MOISTURE AXIS /KEAU SREF MEAN GIVES 0.07
OF FZDZ/ SO IT IS STILL A SYSTEM TO WATCH.

.LONG TERM...WEDNESDAY THROUGH SATURDAY
326 PM CST SAT FEB 16 2013

THE FOCUS REMAINS ON THE INCREASINGLY ADVERTISED LATE WEEK SYSTEM
AND THE DEGREE OF IMPACT IT WILL HAVE ON THE UPPER MIDWEST. LEADING
UP TO THAT FEATURE...WEDNESDAY LOOKS TO BE A TRANSITION DAY WITH
MORNING COLD ADVECTION AS A SURFACE HIGH AND UPPER LEVEL RIDGE AXIS
REMAINS TO THE WEST OF THE FORECAST AREA. A COLD DAY ON TAP AS
MORNING LOWS IN THE SINGLE DIGITS BELOW/ABOVE ZERO LOOK TO RISE INTO
ONLY THE TEENS. THE RIDGE IS THEN EXPECTED TO BUILD ACROSS BY
WEDNESDAY NIGHT...LEADING TO RETURN SOUTHERLY FLOW. A WESTERN CONUS
TROUGH THEN DIGS AND MOVES EAST...EJECTING THE MAIN SHORTWAVE
TROUGH OUT OF THE COLORADO ROCKIES BY 12Z THURSDAY. SURFACE LOW
DEEPENS RAPIDLY ACROSS THE CENTRAL PLAINS THURSDAY...LIFTING
TOWARD THE AREA.

THE 16.12Z GFS ENSEMBLE REMAINS CLOSELY PACKED WITH A LOW TRACK
ALONG A KANSAS CITY TO NORTHERN ILLINOIS LINE THURSDAY NIGHT INTO
FRIDAY AFTERNOON. THE 16.12Z ECMWF TOOK A STEP NORTHWEST WITH ITS
SURFACE LOW TRACK AND THE 16.12Z GEM AND FIM REMAIN THE SOUTHERLY
OUTLIERS. THE GFS SEEMS TO BE A GOOD COMPROMISE. EARLIER TIMING
ISSUES APPEAR TO BE RESOLVED FOR NOW. YESTERDAY/S CONCERNS ABOUT THE
FILLING UPPER LEVEL TROUGH / SURFACE LOW AND ITS IMPACT WERE MUTED
SLIGHTLY SINCE THE 16.12Z GFS...ECMWF AND FIM CAME IN A BIT
STRONGER. HOWEVER...500 MB HEIGHT STANDARDIZED ANOMALIES STILL RISE
FROM -3.5 ACROSS THE CENTRAL PLAINS...TO AROUND -0.5 BY 12Z FRIDAY
WHICH SUGGESTS A WEAKENING TREND AND THE SYSTEM NOT NEARLY AS WOUND
UP AS IT MAY BE IN THE CENTRAL PLAINS.

PRECIPITATION WOULD OVERSPREAD THE AREA DURING THE AFTERNOON
THURSDAY...WITH THE MAIN WARM ADVECTIVE WING SWINGING THROUGH
THURSDAY NIGHT AND OVERNIGHT FRIDAY. THIS WOULD BE WHEN THE HIGHEST
SNOW RATES OCCUR. AS THE SURFACE LOW THEN MOVES NEARBY...WRAP AROUND
/ DEFORMATION BANDING SNOW WOULD LINGER THROUGHOUT FRIDAY. SOUNDINGS
STILL POINT TO AN ALL SNOW EVENT WITH THE WARMEST AIR REMAINING
SOUTH OF THE AREA.

THE MODEL CONSISTENCY AND RUN-TO-RUN SIMILARITIES REMAIN VERY ABOVE
AVERAGE AND REMARKABLE FOR IT STILL BEING 6 DAYS OUT. GIVEN THE
FEATURE IS CURRENTLY OVER THE DATA SPARSE NORTHERN PACIFIC...THERE
CERTAINLY WILL BE FINE-TUNE DETAILS TO ESTABLISH. PRECIPITATION
AMOUNTS TOOK A STEP UP IN THE LATEST ROUND OF GUIDANCE THOUGH STILL
REMAIN BETWEEN 0.7 TO 1.0 INCH. CONFIDENCE CONTINUES TO GROW IN A
WARNING LEVEL EVENT WITH WIDESPREAD 6 TO 10 INCH AMOUNTS IF THE
CURRENT AND PAST SOLUTIONS INDEED VERIFY. THE BIG PICTURE IS THAT
THOSE WITH INTERESTS AND TRAVEL CONCERNS LATE NEXT WEEK SHOULD
CONTINUE TO MONITOR AND FOR NOW...HAVE CONTINUED TO PUSH HIGHER
PRECIPITATION CHANCES THURSDAY NIGHT...AND TRENDED FRIDAY HIGHER AS
WELL SINCE IF THE SYSTEM DOES SLOW DOWN / FILL IN THEN THERE WOULD
CERTAINLY BE LINGERING DEFORMATION BANDING SNOW ACROSS MUCH OF THE
AREA. THE PROLONGED DURATION / THURSDAY NIGHT THROUGH LATE FRIDAY
NIGHT / COULD PRESENT SOME CHALLENGES FOR TRAVELERS AND ROAD CREWS
AS WELL.

.AVIATION...THROUGH 18Z SUNDAY
1128 AM CST SAT FEB 16 2013

THE MAIN CONCERNS ARE IN THE NEAR TERM WITH SKY CONDITIONS AND
SOME LIGHT SNOW POSSIBLY GETTING INTO RST. THIS BAND OF LIGHT SNOW
HAS BEEN JUST TO THE WEST OF RST ALL MORNING AND HAS BROUGHT
VISIBILITY DOWN TO IFR...MAINLY AT 1-2SM. THE CLOUDS DO APPEAR TO
BE DIMINISHING IN COVERAGE AND THAT SHOULD BE THE TREND THROUGH
THE AFTERNOON HOURS. FURTHER EAST AT LSE..MAINLY LOOKING AT A LOW
END VFR BKN CLOUD DECK AT 3500-4500FT THROUGH THE AFTERNOON BEFORE
SUBSIDENCE KICKS IN AND HELPS CLEAR THE CLOUDS LATER THIS
AFTERNOON ON INTO THE EVENING. WINDS WILL REMAIN LIGHT THROUGH THE
NIGHT AS A RIDGE AXIS OF HIGH PRESSURE MOVES THROUGH BUT AFTER IT
PASSES BY TOMORROW MORNING...THE PRESSURE GRADIENT WILL TIGHTEN UP
WITH SOUTHEAST WINDS INCREASING TO 10-20KTS BY LATE MORNING.

.ARX WATCHES/WARNINGS/ADVISORIES...
151 PM CST SAT FEB 16 2013

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...BAUMGARDT
LONG TERM...TAYLOR
AVIATION...HALBACH

AREA FORECAST DISCUSSION

NWS GREEN BAY WI

234 PM CST SAT FEB 16 2013

.SYNOPSIS...
ISSUED AT 223 PM CST SAT FEB 16 2013

MODERATING TEMPS WITH SOME LIGHT TO MODERATE PRECIPITATION MONDAY
NIGHT AND TUESDAY. STILL PLENTY OF QUESTIONS ABOUT THE NEXT SYSTEM
EXPECTED TO ARRIVE LATE IN THE WEEK.

UPR FLOW ACRS NOAM WL START OUT WITH A BROAD RIDGE OVER THE ERN
PAC/WRN NOAM...ALBEIT WITH STG SHRTWV RIGHT IN THE MIDDLE OF THE
RIDGE POSN. A DEEP TROF WAS OVER ERN NOAM...WITH RIDGING OVER THE
WRN ATL. THE SHRTWV NOW IN THE WRN RIDGE POSN AND ITS SUCCESSOR WL
BOTH DIG PROGRESSIVELY FARTHER W...EVENTUALLY PULLING THE MEAN
TROF POSN BACK INTO THE WESTERN CONUS BY MID-WK. MEANWHILE...THE
DOWNSTREAM PATTERN OVER THE ATL WL BREAK DOWN INTO A COMPLEX
BLOCKING REGIME. THE BLOCKING WL EVOLVE WWD WITH TIME...
RESULTING IN A SPLIT FLOW ACRS MUCH OF THE CONUS BY NEXT WEEKEND.

THE TWO MAJOR SHRTWVS WORKING ACRS THE CONUS DURING THE PERIOD WL
BOTH SUPPORT STG CYCLONES. THE CHANGING UPR PATTERN AND PASSAGE OF
THE CYCLONES WL TAKE TEMPS ON A ROLLERCOASTER RIDE DURING THE
PERIOD. THEY/LL START OUT COLD...QUICKLY WARM EARLY IN THE WEEK...
DROP BACK TO BLO NORMAL MID-WEEK...THEN SETTLE BACK CLOSER TO
NORMAL AS THE FLOW SETTLES INTO SPLIT REGIME. GIVEN THE 2 SIG
SYSTEMS LIKELY TO IMPACT THE AREA...PCPN AMNTS WL PROBABLY END UP
AOA NORMAL.
&&

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 223 PM CST SAT FEB 16 2013

LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE RIDGE STRETCHING FROM TEXAS TO ONTARIO THIS AFTERNOON.
STEEPENING LOW LEVEL LAPSE RATES AND FLOW OFF SUPERIOR CONTRIBUTED
TO A WIDESPREAD DIURNAL CU FIELD...WHICH SPREAD SOUTH ACROSS MUCH
OF THE CWA BY EARLY THIS AFTERNOON. LAKE EFFECT SNOW SHOWERS
REMAINED CONFINED TO NORTHERN VILAS COUNTY AND POINTS NORTH AND
VSBYS IN THIS AREA SUGGEST ONLY MINOR ACCUMS AT BEST. PRETTY QUIET
UPSTREAM AS WELL. FGEN INDUCED BAND OF CLOUDS AND LIGHT SNOW OVER
THE PLAINS IS SLIDING SE WHILE SKY CONDITIONS ARE CLEARING OVER
MINNESOTA. CLOUD TRENDS AND TEMPS ARE THE MAIN FORECAST CONCERNS
IN THE SHORT TERM.

TONIGHT...SURFACE HIGH PRESSURE TO MOVE ACROSS THE REGION AND
THIS SHOULD RESULT IN LOW LEVEL FLOW BECOMING LIGHT THIS EVENING.
ANTICIPATING STRATO-CU TO RAPIDLY DIMINISH WITH LOSS OF DAYTIME
HEATING EARLY THIS EVENING...EXCEPT OVER NORTH-CENTRAL WISCONSIN
WHERE IT SHOULD TAKE A FEW HOURS LONGER. AS A RESULT...EXPECT SKY
CONDITIONS TO BECOME CLEAR TO MOSTLY CLEAR ACROSS THE REGION BY
LATE THIS EVENING. STRATUS UPSTREAM THIS MORNING BENEATH THE RIDGE
AXIS SEEMED ALIGNED WITH A LOW LEVEL THERMAL GRADIENT. THIS
GRADIENT DOES NOT MOVE MUCH TONIGHT...SO AM NOT EXPECTING CLOUDS
TO REFORM BENEATH THE SURFACE HIGH. TEMPS LAST NIGHT FELL INTO THE
TEENS BELOW ZERO OVER N-C WISCONSIN. SHOULD HAVE LIGHTER WINDS IN
THE BOUNDARY LAYER AND THE PWAT MINIMUM OVERHEAD...SO HAVE DROPPED
TEMPS FROM THE PREVIOUS FORECAST.

SUNDAY...HIGH PRESSURE MOVES EAST OF THE REGION AND RETURN FLOW
WILL PUSH A WARM FRONT INTO THE NORTHERN MISSISSIPPI VALLEY BY THE
AFTERNOON. THOUGH MID AND HIGH CLOUDS WILL BE INCREASING THROUGH
THE DAY...DEEPER MOISTURE WILL STAY WELL OFF TO THE NORTHWEST OVER
NORTHERN MINNESOTA AND SOUTH-CENTRAL CANADA. HIGHS WILL BE
CONSIDERABLY WARMER THAN TODAYS READINGS...AND MOSTLY RANGE FROM
THE LOWER TO MIDDLE 20S.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 223 PM CST SAT FEB 16 2013

WAA ON THE BACK SIDE OF DEPARTING RIDGE WL KICK INTO HIGH GEAR
SUN NGT. THE STRONGEST ISENT LIFT AND BEST CHC AT SATURATION WL BE
ACRS THE N. WENT WITH CHC POPS THERE...AND KEPT THE S DRY. EXPECT
EVENING MINS THEN RISING TEMPS.

COMPLEX STORM SYSTEM DRIVEN BY PHASING SHRTWVS WL BE ORGANIZING
AS IT CROSSES THE AREA MON...THEN DEEPEN JUST OFF TO OUR E MON NGT
INTO TUE. RAISED POPS AS FORCING LOOKS FAIRLY STG. BUT MOISTURE WL
BE LIMITED...ESP INITIALLY. THAT WL PROBABLY RESULT IN ANOTHER
EVENT WITH MESSY MIX OF SN/DZ/FZDZ DEPENDING ON WHETHER SUFFICIENT
MID-LVL MOISTURE IS PRESENT AT ANY TIME TO SEED THE LOWER CLDS FM
ABV. MODEL FCST SOUNDINGS SUGGEST LOWER-LEVELS OVER E-C WI COULD
BRIEFLY BE WARM ENOUGH FOR JUST RAIN MON AFTN EVEN IF MOISTURE IS
DEEP AT THAT TIME. WENT WITH MAINLY SN/FZDZ ACRS THE NW AND RA/SN
IN THE SE ON MON. E-C WI COULD CERTAINLY SEE DZ RATHER THAN
RAIN... BUT WANTED TO AVOID HAVING TOO MANY PCPN TYPES IN THE
FCST.

PCPN SHOULD CHG TO SNOW MON NGT...WITH SHSN ON THE BACK SIDE OF
THE SYSTEM CONTG INTO TUE. UPPED POPS AS UPR TROF WL BE SHARPENING
RIGHT ACRS THE AREA DURING THAT TIME. THINKING RIGHT NOW IS THAT
THIS WL BE A 1-3 INCH EVENT...WITH THE HIGHER TOTALS IN THE NE.
LAKE-EFFECT OFF LAKE SUPERIOR COULD BOOST TOTALS EVEN FURTHER OVER
THE SNOWBELT...THOUGH THAT DEPENDS ON EXACT TRAJECTORIES SO WON/T
GET TOO SPECIFIC WITH THAT YET.

A BREAK FM THE SIG PCPN THEN EXPECTED WED INTO THU AS UPR RIDGE
SHARPENS ACRS THE AREA. STG...COLD...VERY DRY LOW-LEVEL
ANTICYCLONE WL BE RIDGING SWD INTO THE RGN FM THE HUDSON BAY AREA.
LOW-LEVEL WINDS WL VEER ARND TO THE E...AND ALTHOUGH THE UPSTREAM
AIR WL BE VERY DRY AND INVERSION HEIGHTS WL BE LOW...WL PROBABLY
GET SOME LAKE FLURRIES INTO E-C WI.

STILL A LOT OF QUESTIONS ABOUT THE SYSTEM HEADING INTO THE AREA
DURING THE LATTER PART OF THE WEEK. DON/T LIKE THAT THE SYSTEM WL
BE DRIVING INTO A DOWNSTREAM BLOCK AND HAVE VERY DRY AIR FEEDING
INTO IT FM THE E AT LOW-LEVELS. THAT/S A CLASSIC LATE WINTER/EARLY
SPRING FCST PROBLEM HERE...AND IT TYPICALLY RESULTS IN A CONSTANT
DELAYING OF THE ONSET OF PCPN...AND OFTEN A REDUCTION IN PCPN
TOTALS. ON THE OTHER HAND...IF SYSTEM CAN GET PCPN INTO THE
AREA...DOWNSTREAM BLOCKING WL CAUSE IT TO SLOW TO A CRAWL...AND
RESULT IN A LONG-DURATION EVENT.

FEELING RIGHT NOW IS THAT THIS IS A SYSTEM THAT WL HAVE IT/S
GREATEST IMPACT OUT IN THE PLAINS. MAX SNOWS WL PROBABLY END UP IN
THE SW PART OF THE FCST AREA...AND THEY WILL PROBABLY BE
CONSIDERABLY LESS THAN WHAT FALLS TO OUR SW. AT THIS POINT...WAS
CONTENT WITH INITIALIZATION GRIDS THAT NEVER WENT BEYOND LIKELY
POPS. CERTAINLY PLENTY OF TIME FOR LATER SHIFTS TO ADJUST FCST.
WL CONT TO MENTION SYSTEM IN THE HWO...BUT DON/T PLAN ON PLAYING
THIS UP AS A BIG STORM.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1132 AM CST SAT FEB 16 2013

AS NORTH FLOW CONTINUES OFF LAKE SUPERIOR...CONDITIONS TO BECOME
SCT TO BKN THIS AFTERNOON...HIGHER PROBABILITIES OVER NORTH-
CENTRAL AND NORTHEAST WISCONSIN THAN FOR CENTRAL WISCONSIN. MVFR
CIGS WILL LIKELY IMPACT RHI AND POSSIBLY AUW/CWA THIS
AFTERNOON...BUT SNOW SHOWERS SHOULD REMAIN NORTH OF THE
AIRPORTS...FROM VILAS COUNTY TOWARDS LAKE SUPERIOR. HIGH PRESSURE
OVER THE AREA TONIGHT WILL HELP SKIES CLEAR AND WINDS BECOME LIGHT
AND VARIABLE. MID AND HIGH CLOUDS WILL BE ON THE INCREASE ON
SUNDAY AHEAD OF AN APPROACHING WARM FRONT...BUT ANY THREAT OF
PRECIP TO HOLD OFF UNTIL SUNDAY NIGHT.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....MPC
LONG TERM......SKOWRONSKI
AVIATION.......MPC

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

1128 AM CST SAT FEB 16 2013

.SHORT TERM...THIS MORNING AND AFTERNOON
1003 AM CST SAT FEB 16 2013

CURRENTLY TRACKING A BAND OF LIGHT SNOW MOVING ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA WHICH HAS DROPPED VISIBILITY DOWN TO
LESS THAN A MILE AT TIMES. SOME OF THAT MAY BE DUE TO SOME FOG
BEING REPORTED IN CENTRAL MINNESOTA...BUT MOST OF THE VISIBILITY
REDUCTIONS SHOULD BE DUE TO THE SNOW FALLING. AUSTIN CITY POLICE
REPORTED THAT THERE WERE LARGE SNOW FLAKES COMING DOWN AROUND 9AM
AND THAT SOME MINOR ACCUMULATIONS WERE BEGINNING. THE FORCING TO
PRODUCE THIS SNOW APPEARS TO BE FROM WARM AIR ADVECTION AROUND
925MB ACCORDING TO 16.14Z RAP BUFKIT SOUNDINGS. THESE SOUNDINGS
ALSO SHOW THE SATURATED THERMAL PROFILE BEING IN THE PEAK
DENDRITIC GROWTH ZONE FROM THE SURFACE UP THROUGH ITS SATURATED
LAYER AT ABOUT 4KFT. THE 16.14Z RAP SHOWS THIS AREA OF HIGH LOW
LEVEL RELATIVE HUMIDITY AND WARM AIR ADVECTION PROPAGATING TO THE
SOUTHEAST THROUGH THE EARLY PART OF THE AFTERNOON BEFORE ENTERING
NORTHERN ILLINOIS AFTER 21Z. SO THE PRECIPITATION SHOULD END THEN.
BASED ON ALL THIS...UPDATED THE FORECAST TO GO FROM FLURRIES TO
THE PERIODS OF SNOW SHOWER THROUGH A PORTION OF SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THROUGH 21Z. ALSO ENDED THE FLURRIES
AFTER 21Z REGION-WIDE...BUT THAT WILL HAVE TO BE RE-EVALUATED THIS
AFTERNOON BASED ON THE CLOUD COVER AT THAT TIME.

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
240 AM CST SAT FEB 16 2013

THIS SYSTEM WILL THEN PULL AWAY FROM THE REGION MONDAY NIGHT AND
TUESDAY WITH A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS THE
ENTIRE AREA MONDAY NIGHT AND JUST IN THE I94 CORRIDOR TUESDAY.

AS THIS SYSTEM APPROACHES THE EAST COAST OF CANADA...THE MODELS
NOW SHOW IS SLOWS CONSIDERABLY WITH RIDGING BUILDING OVER THE
CENTRAL PORTIONS OF THE COUNTRY. THE NEXT SYSTEM WILL COME ONSHORE
AND INTO THE ROCKIES TO FORM AN OMEGA BLOCK TYPE PATTERN BY
WEDNESDAY. HOWEVER...THE SYSTEM COMING IN FROM THE WEST IS
EXPECTED TO CONTINUE AN ATTEMPT TO MOVE INTO THE RIDGE AS THERE
WILL BE MORE SYSTEMS TOPPING THE PACIFIC RIDGE AND MOVING TOWARD
THE ROCKIES. THE MODELS NOW SHOW THE FIRST SYSTEM COMING OUT OF
THE WEST TO LIFT INTO THE NORTHERN PLAINS BY FRIDAY AS THE
DOWNSTREAM BLOCK REMAINS IN PLACE AND BEGINS TO FILL IN. THIS IS A
DRAMATIC SHIFT IN THE UPPER AIR PATTERN FROM PREVIOUS MODEL RUNS
WHICH DID NOT SHOW AN OMEGA BLOCK DEVELOPING AND WERE PROGRESSIVE
WITH THE SYSTEM. THE SURFACE LOW IS NOW HANDLED QUITE DIFFERENTLY
BY THE MODELS WITH THEM SHOWING A VERY DEEP LOW COMING OUT OF THE
SOUTHERN ROCKIES WEDNESDAY NIGHT. WITH A FILLING UPPER LEVEL
LOW...ALL THE MODELS SHOW THE SURFACE SYSTEM TO BE FILLING AS
WELL...BUT TO DIFFERENT DEGREES ON HOW FAST THIS WILL HAPPEN.
WOULD HAVE PREFERRED TO LET THE MODEL CONSENSUS GRIDS RIDE UNTIL
CONFIDENCE ON HOW THIS SYSTEM WILL EVOLVE BECOMES HIGHER.
HOWEVER...UNABLE TO DO THIS AND HAD TO RAISE THE PRECIPITATION
CHANCES THURSDAY AFTERNOON AND NIGHT TO REMAIN IN COLLABORATION
WITH SURROUNDING OFFICES. ENDED UP WITH 60 PERCENT ACROSS THE
SOUTHWEST THURSDAY AFTERNOON ON THE LEADING EDGE OF THE
PRECIPITATION SHIELD AND THEN 70 PERCENT FOR MUCH OF THE AREA
THURSDAY NIGHT.

.AVIATION...THROUGH 18Z SUNDAY
1128 AM CST SAT FEB 16 2013

.ARX WATCHES/WARNINGS/ADVISORIES...
240 AM CST SAT FEB 16 2013

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...HALBACH
LONG TERM...04
AVIATION...HALBACH

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

1003 AM CST SAT FEB 16 2013

.SHORT TERM...THIS MORNING AND AFTERNOON
1003 AM CST SAT FEB 16 2013

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
240 AM CST SAT FEB 16 2013

THIS SYSTEM WILL THEN PULL AWAY FROM THE REGION MONDAY NIGHT AND
TUESDAY WITH A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS THE
ENTIRE AREA MONDAY NIGHT AND JUST IN THE I94 CORRIDOR TUESDAY.

.AVIATION...TODAY AND TONIGHT
513 AM CST SAT FEB 16 2013

STRATUS WILL PRODUCE PERIODS OF MVFR CONDITIONS AND FLURRIES AT THE
TAF SITES THROUGH THE LATE MORNING HOURS. PLAN ON CLOUD BASES IN
THE 2500 TO 3500 FT RANGE. THE STRATUS SHOULD BECOME SCATTERED
THIS AFTERNOON AS THE HIGH MOVES IN. HOWEVER...GUIDANCE SUGGESTS
THE STRATUS COULD HOLD ON RIGHT ALONG AND EAST OF THE MISSISSIPPI
RIVER LATE THIS AFTERNOON INTO THIS EVENING IMPACTING KLSE.
THINKING THE STRATUS WILL MIX OUT DURING THE AFTERNOON HOURS BUT
WILL HAVE TO KEEP A CLOSE EYE ON THIS. VFR CONDITIONS ARE EXPECTED
DURING THE OVERNIGHT HOURS. SCATTERED TO BROKEN MID LEVEL CLOUDS
WILL MOVE IN FROM THE WEST LATE TONIGHT AS A STORM SYSTEM MOVES
INTO THE NORTHERN PLAINS. WINDS WILL BECOME LIGHT AND VARIABLE
TODAY AS THE HIGH MOVES IN. LOOK FOR WINDS TO SWITCH TO THE
SOUTHEAST AT 5 TO 10 KTS TONIGHT AS THE HIGH SLIDES EAST OF THE
REGION.

.ARX WATCHES/WARNINGS/ADVISORIES...
240 AM CST SAT FEB 16 2013

WI...NONE.
MN...NONE.
IA...NONE.

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

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

1048 PM CST FRI FEB 15 2013

.SHORT TERM...THROUGH MONDAY NIGHT
319 PM CST FRI FEB 15 2013

BENIGN WEATHER THROUGH THE WEEKEND LEADS INTO MONDAYS WEATHER
SYSTEM WHICH WILL NEED TO BE WATCHED FOR CHANGES.

MUCH LESS CLOUD ACROSS THE AREA TODAY THAN FORECAST WITH MIXING
NOT DEEP ENOUGH TO FORM MUCH STRATOCUMULUS EXCEPT OVER
NORTH-CENTRAL WI. LONGWAVE TROUGH AXIS CONTINUES EASTWARD PROGRESS
WITH LAST OF SHORTWAVE TROUGH ENERGY COMING THROUGH TONIGHT AND
EARLY SATURDAY. LATEST RAP AND WATER VAPOR HAS THIS BROAD
CIRCULATION AXIS FROM KINL-KLBF...AND SURFACE LOW PRESSURE IN
EASTERN NEB. CLOUD COVER OVER NWRN MN MOVING TOWARD THE AREA WILL
ARRIVE THIS EVENING FOR A CLOUD PERIOD INTO SATURDAY MORNING. NOT
TO CONFIDENT ON THE COVERAGE OF THIS CLOUD COMING IN...IT MAY BE
MORE IN AREAS. HAVE LEFT A MENTION OF FLURRIES IN THIS WEAKLY
LIFTED AIR MASS THROUGH NOON SATURDAY.

AGGRESSIVE RIDGE BUILDING THEN TAKES PLACE LATER SATURDAY AND
SUNDAY. UPSTREAM RAOB HEIGHT RISES SEEN ACROSS WRN CANADA WITH
THIS PROGRESSIVE HIGHER AMPLITUDE RIDGE. HAVE COOLED THE LOW
TEMPERATURES SUNDAY MORNING OVER CENTRAL WI WITH NEARLY CALM WINDS
AND LITTLE CLOUD UNDER LOW-LEVEL RIDGING. THESE ARE BELOW MOS
GUIDANCE BY ABOUT 5-7F. WARM ADVECTION WILL BEGIN TO RAISE
TEMPERATURES SUNDAY AND THE FORCING DOES NOT SEEM SUFFICIENT TO
CREATE PRECIPITATION PER CONSENSUS 15.12Z MODEL GUIDANCE.
HOWEVER...THE WARM ADVECTION AND THERMAL RIBBON LIFTING ACROSS THE
AREA WILL CREATE AN ARC OF CLOUDS ORIENTED NW-SE TO SHIFT NEWRD
ACROSS THE AREA. HAVE INCREASED SKY COVER A BIT FOR SUNDAY...SOME
FLURRIES MAY BE POSSIBLE BUT HAVE NOT INCLUDED THEM IN THE
FORECAST.

FAIRLY INTERESTING TROUGH TO SHIFT INTO THE AREA MONDAY. THE
TROUGH IS CURRENTLY IN THE ERN PACIFIC APPROACHING 47N/140W PER
GOES WATER VAPOR. MODEL GUIDANCE CONSENSUS FROM 15.12Z IS THAT
THERE WILL NRN AND SRN ENERGY IN THIS TROUGH. THE SRN PIECE OF
ENERGY IS HANDLED DIFFERENTLY BY THE LATEST GUIDANCE. THE 15.12Z
NAM/SREF DEVELOP ONLY A WEAK CYCLONE VIA THE SRN ENERGY...WHILE THE
GEM GLOBAL AND 15.00Z FIM MODEL ARE AGGRESSIVE WITH THE CYCLONE
DEEPENING IT ALONG A KANSAS CITY TO MILWAUKEE TRACK...AND DROPPING
A 4-8 INCH SNOW BAND ACROSS WI. 15.12Z ECMWF/GFS ARE SIMILAR AND
OFFER A COMPROMISE BETWEEN THE TWO CAMPS WITH THE CYCLONE
DEEPENING LATER...INTO MICHIGAN. HAVE GONE WITH THIS COMPROMISE ON
TIMING AND INTENSITY.

MONDAY WILL SEE A GULF SURGE OF MOISTURE IN THE SOUTHERLY FLOW...
DEEPENING A SURFACE-BASED LAYER TO OVER 1 KM DEEP. THIS WILL BE
PRE-FRONTAL IN THE SOUTHERLY FLOW AND WITHOUT DEEP CLOUD AND
ICE...BUT ISENTROPIC LIFT OF 3-5 UB/S IN THE LAYER ...DZ/FZDZ
WILL BE POSSIBLE. THE MOIST TONGUE IS MAINLY IN WI AND EAST AND
THAT IS WHERE DZ/FZDZ CHANCES WILL BE BEST. TEMPERATURES WILL BE
WARMING MONDAY WITH ABOVE FREEZING HIGHS AROUND I-90 AND SOUTH
EXPECTED. THUS...DZ OR RAIN SHOWERS COULD BE FREEZING IN THE EARLY
AFTERNOON IF ROADS DO NOT RESPOND TO WARMING. WITH QPFS LESS THAN
0.10 INCHES...WOULD EXPECT ONLY LIGHT ICING TO OCCUR. AS TROUGH
SHIFTS EAST LATE MONDAY AND MONDAY EVENING...A TRANSITION TO SNOW
WILL OCCUR FROM WEST TO EAST WITH SNOW AMOUNTS OF LESS THAN AN
INCH. HAVE INCREASED PRECIPITATION CHANCES OVERALL...BUT WI LOOKS
TO BE THE MAIN WEATHER AREA FOR THIS SYSTEM. THERE IS A CHANCE
THIS COULD NEED AN ADVISORY IF FREEZING PRECIPITATION LOOKS MORE
WIDESPREAD OR THE MORE AGGRESSIVE CYCLONE SOLUTION IN THE GEM
SHOULD BECOME MORE PROBABLE. THE SPREAD IN THE CYCLOGENESIS SEEN
FROM THE SRN ENERGY IN THE MODEL GUIDANCE SUGGESTS THIS IS AN
UNSTABLE SYSTEM AND COULD LEAD TO FORECAST CHANGES. WILL TAKE A
STEP UP IN OUR FORECAST VISIBILITY OF THIS SYSTEM.

.LONG TERM...TUESDAY THROUGH FRIDAY
319 PM CST FRI FEB 15 2013

ACTIVE EXTENDED PERIOD SETTING UP WITH THE FOCUS ON A SHORT ARCTIC
INTRUSION MID WEEK FOLLOWED BY THE POTENTIAL OF A WINTER STORM TO
IMPACT THE UPPER MIDWEST NEXT THURSDAY NIGHT AND FRIDAY.

GOING INTO TUESDAY...A LOT DEPENDS ON THE EVOLUTION AND PHASING OF
THE STORM SYSTEM THAT IS EXPECTED TO TRACK THROUGH MONDAY AND MONDAY
NIGHT...AND HOW MUCH ARCTIC AIR IS PULLED SOUTH IN ITS WAKE. 15.12Z
GUIDANCE SHOWS SIMILAR SOLUTIONS FOR 850 MB TEMPERATURES TO PLUMMET
AS LOW AS -15C TO -20C TUESDAY AND WEDNESDAY. STANDARDIZED
ANOMALIES FOR THIS PERIOD RANGE FROM 1 TO 1.5 BELOW NORMAL AND WITH
BROAD CYCLONIC FLOW ALOFT...IT WILL MAKE FOR A COUPLE COLD WINTER
DAYS. HIGHS IN THE TEENS AND OVERNIGHT LOWS IN THE SINGLE DIGITS
ABOVE ZERO...WITH OCCASIONAL LIGHT SNOW OR FLURRIES TUESDAY.

THE COLD AIRMASS SETS THE STAGE FOR LATER IN THE WEEK AS A WESTERN
CONUS TROUGH DEEPENS AND MOVES EAST. AS HAS BEEN ALLUDED TO IN
PREVIOUS DISCUSSIONS...THE RUN-TO-RUN AND MODEL CONSISTENCY FOR
THIS FEATURE REMAINS VERY HIGH. DETERMINISTIC MODELS STILL POINT
FOR A SURFACE LOW TRACK THROUGH THE CENTRAL PLAINS TO NORTHERN
ILLINOIS BY 12Z FRIDAY BRINGING WIDESPREAD PRECIPITATION TO THE
ENTIRE AREA WITH A CLASSIC DEFORMATION BAND OF SNOW SETTING UP.
LOOKING AT THE 15.12Z GFS ENSEMBLE...SURFACE LOW TRACK LOCATIONS
VARY FROM EASTERN IOWA...SOUTHERN WISCONSIN...AND ILLINOIS.
SIMILAR IDEAS ARE FOUND IN THE 15.00Z ECMWF ENSEMBLE. THE
STABILITY AND LACK OF SPREAD WITHIN THE NUMERICAL GUIDANCE FOR
THIS WEATHER SYSTEM ARE VERY HIGH.

ONE ISSUE THAT MAY PRECLUDE THIS FROM BEING A MORE SIGNIFICANT EVENT
IS THAT THE BOTH THE UPPER LEVEL AND SURFACE WAVES APPEAR TO BE
WEAKENING AS IT APPROACHES THE UPPER MIDWEST. 500 MB STANDARDIZED
ANOMALIES DROP FROM -2.5 ACROSS KANSAS TO BARELY BELOW NORMAL AS IT
CROSSES THE AREA. THIS IS REFLECTED IN THE SURFACE LOW PRESSURE
WHICH REMAINS AROUND 1000 MB THROUGHOUT. EARLIER RUNS SHOWED DEEPER
CYCLOGENESIS WITH 980-990 MB LOWS. THE 15.12Z ECMWF REALLY DAMPENS
OUT THE UPPER LEVEL AND SURFACE WAVE...BECOMING ALMOST OCCLUDED BY
FRIDAY AFTERNOON.

TEMPERATURE PROFILES ACROSS THE AREA CONTINUE TO SHOW AN ALL SNOW
EVENT...THOUGH THERE IS A SLIGHT WARMING TREND NOTED. IF THE
SYSTEM WERE TO DEEPEN AND WRAP UP MORE...THEN A PUSH OF WARMER AIR
COULD PRESENT A RAIN/SNOW MIX BUT RIGHT NOW THIS IS NOT THE CASE.
HAVE TRENDED PRECIPITATION CHANCES ABOVE MODEL CONSENSUS THURSDAY
NIGHT GIVEN CONTINUED EXCELLENT MODEL AGREEMENT AND THE SLOWER
TIMING OF THE SYSTEM.

ALTHOUGH IT IS A BIT TOO EARLY TO SPECULATE ON AMOUNTS...25.12Z GFS
ENSEMBLE AND 25.12Z ECMWF SHOW WIDESPREAD AMOUNTS OF 0.50 TO 0.75
INCHES OF LIQUID. SNOW RATIOS ARE NOT VERY HIGH...MOST LIKELY A BIT
BELOW CLIMATOLOGICAL VALUES /10 TO 12:1/ SO IN SHORT...WARNING
LEVEL /6 INCHES/ SNOW TOTALS COULD BE MET OR EXCEEDED ACROSS PARTS
OF THE REGION.

.AVIATION...THROUGH 06Z SUNDAY
1048 PM CST FRI FEB 15 2013

CONFIDENCE HAS INCREASED THAT MVFR STRATUS WILL AFFECT THE TAF
SITES THIS MORNING. AN AREA OF MVFR STRATUS WAS PRESENT OVER
WESTERN MINNESOTA...JUST TO THE EAST OF A HIGH PRESSURE RIDGE IN
EASTERN SOUTH DAKOTA. THIS STRATUS HAS BEEN MOVING EASTWARD AND
EXPANDING. EXTRAPOLATION ALONG WITH NAM/RAP MODEL FORECASTS BRING
THE STRATUS INTO KRST AROUND 10Z AND KLSE AROUND 12Z. FLURRIES
HAVE ALSO BECOME MORE PREVALANT WITHIN THE STRATUS...AND WITH THE
CONFIDENCE NOW HIGHER ABOUT THE STRATUS AFFECTING THE TAF SITES...
ADDED -SHSN BACK IN. THE CLEARING TIME OF THE STRATUS IS STILL A
LITTLE UNCERTAIN...BUT GIVEN THAT THE WEST SIDE OF THE STRATUS
BANK IS MOVING AND DAYTIME MIXING WILL HELP OUT...GIVES CONFIDENCE
THE STRATUS DECK WILL NOT GET STUCK. HAVE KEPT THE 20Z TIME FOR
SCATTERING OUT OF THE CLOUDS...IN AGREEMENT TOO WITH THE NAM MODEL
FORECAST. CLEAR SKIES SHOULD DOMINATE MUCH OF THE EVENING AS THE
RIDGE OF HIGH PRESSURE BECOMES FIRMLY IN CONTROL. EXPECT WINDS TO
GENERALLY REMAIN LIGHT...LESS THAN 10 KT...DUE TO THE HIGH
PRESSURE RIDGE BUILDING IN.

.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CST FRI FEB 15 2013

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...BAUMGARDT
LONG TERM...TAYLOR/BAUMGARDT
AVIATION...AJ

AREA FORECAST DISCUSSION

NWS CHEYENNE WY

448 PM MST SUN FEB 17 2013

AVIATION...00Z TAFS

CONCERNS ARE FOR KRWL AND POSSIBLY KLAR LATER TONIGHT AS A COLD
FRONT MOVES THROUGH THE AREA. CURRENTLY...FRONT JUST NORTH OF
RAWLINS. SNOW SHOWERS DEVELOPING ON RIVERTON RADAR AND WEBCAMS
SHOWING LOWERING CONDITIONS WEST OF RAWLINS. DO THINK THERE IS A
PERIOD...SAY 03Z TO MAYBE 09Z WHERE KRWL COULD GO IFR IN LOW
CEILINGS AND SNOW. LATEST HRRR MODEL RUN CONFIRMS THIS CONCERN AND
EVEN BRINGS IFR CONDITIONS INTO KLAR AND KCYS. WILL CONTINUE TO
MONITOR...BUT CONFIDENCE IS HIGH ENOUGH TO KEEP LOW CONDITIONS OUT
OF THE KCYS TAF FOR NOW. KLAR MAY SEE LOWER CONDITIONS AFTER 06Z
AND WILL REEVALUATE FOR THE 06Z TAFS.

CLAYCOMB

PREV DISCUSSION... /ISSUED 359 PM MST SUN FEB 17 2013/

SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...
UPPER LEVEL DISTURBANCE STILL ON TRACK TO MOVE ACROSS THE AREA
TONIGHT. SCATTERED RAIN AND SNOW SHOWERS ARE MAINLY NORTHWEST OF
THE AREA AT THIS TIME...ALTHOUGH STARTING TO SEE SOME CONVECTIVE
TYPE CLOUDS UNDER THE CIRRUS CANOPY. ALSO STARTING TO SEE SHOWERS
NEAR CASPER WHICH WILL SPREAD SOUTHEAST INTO THE AREA THIS
AFTERNOON AND EVENING AS THE UPPER DISTURBANCE SHIFTS ACROSS
SOUTHEAST WYOMING. COOLING ALOFT SHOULD KEEP THE LOW TO MID LEVEL
LAPSE RATES ON THE HIGH SIDE THROUGH THIS EVENING. THIS SHOULD
KEEP THE SHOWER ACTIVITY GOING...ESPECIALLY IN HIGHER ELEVATIONS
AND THE MOUNTAINS. STILL LOOKS LIKE THE SNOWY AND SIERRA MADRE
RANGES WILL BE THE BIG WINNERS WITH GENERALLY 3 TO 6 INCHES OF
SNOW EXPECTED. MOISTURE WILL BE LIMITED WITH THIS SYSTEM...
ESPECIALLY STARTING OUT AS EVIDENT BY THE SINGLE DIGIT RELATIVE
HUMIDITY AT CHEYENNE THIS AFTERNOON. EVENTUALLY THE ATMOSPHERE WILL
MOISTEN UP BUT NOT ENOUGH TO PRODUCE MUCH MORE THAN A FEW
FLURRIES TO A DUSTING OF SNOW EAST OF THE LARAMIE RANGE. COULD
SQUEEZE OUT AN INCH OR SO OF SNOW AT LOWER ELEVATIONS WEST OF THE
LARAMIE RANGE TONIGHT WITH ANY STRONGER SNOW SHOWERS.

COLD FRONT ASSOCIATED WITH THE UPPER DISTURBANCE HAS ALREADY MADE
ITS WAY THROUGH DOUGLAS AS EVIDENT BY FALLING TEMPERATURES AND
SURFACE PRESSURE RISES. WINDS WILL SHIFT NORTH TO NORTHWEST WITH
FROPA WITH SOME STRONGER WINDS EAST OF THE LARAMIE RANGE AND INTO
THE NEBRASKA PANHANDLE. ONE CONCERN IS THE POTENTIAL FOR WIND
ADVISORY STRENGTH WINDS IN THE PANHANDLE. MAY APPROACH WIND
ADVISORY SPEEDS FOR A BRIEF PERIOD FOLLOWING FROPA THIS
EVENING...BUT THE MAIN THREAT IS LATE MONDAY MORNING THROUGH
MONDAY AFTERNOON AS SURFACE HEATING MAY ALLOW STRONGER WINDS ALOFT
TO MIX TO THE SURFACE. OF COURSE THERE MAY BE ENOUGH MID CLOUD
AROUND TO INHIBIT DEEP ENOUGH MIXING TO HIT ADVISORY. TOUGH CALL
AT THIS POINT. AFTER COLLABORATION WITH THE NORTH PLATE
OFFICE...OPTED NOT TO ISSUE AN ADVISORY AT THIS TIME. MAY BE
PRUDENT TO WAIT AN SEE WHAT THE EVENING MODELS DO. MOS GUIDANCE
VALUES AT SEVERAL NEBRASKA SITES SHOWING 25 TO 29 KTS WINDS WITH
26 KT SUSTAINED NEEDED FOR ADVISORY.

MUCH COOLER MONDAY WITH HIGH TEMPERATURES A GOOD 20 DEGREES LOWER
WITH MOST OF THE FORECAST AREA STRUGGLING TO REACH 30 DEGREES.
HIGHS MAINLY IN THE 20S WEST OF THE LARAMIE RANGE WITH UPPER 20S
TO MID 30S EAST. INSTABILITY SNOW SHOWERS EXPECTED OVER THE
MOUNTAINS MONDAY. COULD SEE A FEW LIGHT SNOW SHOWERS OR FLURRIES
ELSEWHERE. NOT EXPECTING ANY MEASURABLE PRECIPITATION INTO THE
NEBRASKA PANHANDLE MONDAY...BUT WOULD NOT BE SURPRISED TO SEE A FEW
FLURRIES IN THE AFTERNOON.

DRY AND WARMER TUESDAY WITH AND UPPER LEVEL RIDGE MOVING ACROSS
THE ROCKIES. DEVELOPING LEE SIDE TROUGH AND UPSLOPE FLOW SHOULD
KEEP TEMPERATURES FROM REACHING FULL MIXING POTENTIAL TUESDAY FOR
AREAS EAST OF THE LARAMIE RANGE. COULD SEE A FEW LIGHT SNOW
SHOWERS INTO THE SNOWY AND SIERRA MADRE RANGE LATE TUESDAY
NIGHT...BUT THE MAIN POTENTIAL FOR SNOW SHOULD HOLD OFF UNTIL
LATER WEDNESDAY.

LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT...12Z MODELS
CONTINUE TO SHOW A FAIRLY CONSISTENT TREND WITH THE EVOLUTION OF
THE STRONG UPPER LOW TAKING AIM AT THE CENTRAL US MIDWEEK. THE
UPPER LOW CENTER WILL SWING FROM THE DESERT SOUTHWEST ON WEDNESDAY
AND INTO THE CENTRAL PLAINS ON THURSDAY. THE SYSTEM LOOKS TO
BECOME STACKED AS IT ENTERS THE PLAINS EARLY THURSDAY
MORNING...WITH DEEP LAYER FLOW OVER THE FORECAST AREA STEADILY
INCREASING AND SWITCHING FROM THE SSE...TO EAST...AND THEN NNE AS
THIS OCCURS. THE STRONG...DEEP LAYER SOUTHEAST FLOW INITIALLY WILL
ADVECT LLVL MOISTURE INTO THE EASTERN PLAINS ON WEDNESDAY...WITH
UPSLOPE/ADVECTION FOG LOOKING LIKELY WEDNESDAY NIGHT INTO THURSDAY
ACROSS THE INTERSTATE 80 CORRIDOR AND RIVER VALLEY LOCATIONS IN
THE EASTERN PLAINS. THE SFC LOW ASSOCIATED WITH THIS SYSTEM WILL
INTENSIFY OVER THE TX/OK PANHANDLE/SW KANSAS REGION EARLY THURSDAY
MORNING UNDER THE STRONGEST AREA OF PVA...AND WILL DRAG DOWN
COLDER AIR FROM THE NORTH ONCE SFC WINDS SHIFT TO THE NORTH. THE
SOURCE REGION OF THE COLDER AIR LOOKS TO BE THE UPPER PLAINS AND
MIDWEST...SO NOT EXPECTING TEMPS TO BECOME TOO COLD ACROSS THE CWA
BEHIND THIS DEVELOPING COLD FRONT. IN ADDITION...CAA AND
FRONTOGENETICAL FORCING WILL BE RELATIVELY WEAK. AS WITH LAST
WEEKS STORM...THIS STORM LOOKS TO BE A FAST MOVING SYSTEM WITH
BEST CHANCE FOR SNOWFALL TO OCCUR WITHIN THE DEEPEST UPSLOPE
REGIME OVER WYOMING ON WEDNESDAY INTO WEDNESDAY NIGHT...WITH THE
PANHANDLE LIKELY SEEING A GOOD SHOT OF SNOW AS THE SYSTEM TREKS
NORTHEAST ON WEDNESDAY NIGHT INTO THURSDAY. MAINTAINED LIKELY
POPS IN THESE AREAS AS THERE IS STILL PLENTY OF TIME FOR THE
MODELS TO MAKE ADJUSTMENTS THAT COULD CHANGE THE TRACK OF THE
STORM AND PRECIP POTENTIAL. ANTICIPATING ACCUMULATIONS TO OVERALL
BE ON THE LIGHT TO MODERATE SIDE...WITH THE MOUNTAINS HIGHER AS IS
TYPICAL. SFC WINDS OVERALL DO NOT LOOK THAT STRONG ACROSS THE
FORECAST AREA WITH THE ANTICIPATED WEAKER CAA PATTERN AND LACK OF
STRONG SFC HIGH PRESSURE DEVELOPING BEHIND THE SYSTEM.

ANOTHER WEAKER SHORTWAVE TROUGH WILL MOVE INTO THE FORECAST AREA BY
FRIDAY MORNING AND WILL LIKELY REINFORCE SNOW IN THE HIGH COUNTRY
AND NORTHERN ZONES THURSDAY NIGHT INTO FRIDAY. NW FLOW AT THE SFC
IN THE WAKE OF THE FIRST SYSTEM SHOULD KEEP THE SOUTHERN ZONES
ACROSS THE PLAINS ON THE DRY SIDE. THIS SHORTWAVE TROUGH WILL ACT
TO DEEPEN THE LEESIDE PRESSURE TROUGH THURSDAY NIGHT INTO
FRIDAY...SO WESTERLY SFC WINDS IN THE WIND CORRIDOR WILL INCREASE
FOR FRIDAY...AND MORE SO ON SATURDAY AS YET ANOTHER UPPER LEVEL
SHORTWAVE DIVES SOUTHEAST INTO THE GREAT BASIN IN NW FLOW ALOFT.
WILL HAVE TO WATCH FOR HIGH WIND POTENTIAL DURING THIS TIME FRAME.
FRIDAY NIGHT AND SATURDAY WILL BE DRY FOR THE MOST PART EXCEPT ALONG
THE WESTERN SLOPES WHERE LIGHT SNOW LOOKS TO PERSIST IN UPSLOPE
FLOW. COULD SEE LIGHT SNOW MOVE INTO THE EASTERN PLAINS AS THIS
NEXT SYSTEM MOVES OVERHEAD INTO THE CENTRAL PLAINS ON SUNDAY.

FIRE WEATHER...
NO FIRE WEATHER CONCERNS THE NEXT SEVERAL DAYS. GUSTY WINDS
TONIGHT ACROSS THE PLAINS WITH SOME SNOW SHOWERS INTO SOUTHEAST
WYOMING. SEVERAL INCHES OF SNOW POSSIBLE INTO THE MOUNTAINS
TONIGHT. COLDER MONDAY WITH SCATTERED MOUNTAIN SNOW SHOWERS. THEN
WARMER TUESDAY WITH A RIDGE IN PLACE. WIDESPREAD SNOW POSSIBLE
LATE WEDNESDAY INTO THURSDAY.

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM/AVIATION...RJM

AREA FORECAST DISCUSSION

NWS CHEYENNE WY

422 PM MST SUN FEB 17 2013

.AVIATION...00Z TAFS

CONCERNS ARE FOR KRWL AND POSSIBLY KLAR LATER TONIGHT AS A COLD
FRONT MOVES THROUGH THE AREA. CURRENTLY...FRONT JUST NORTH OF
RAWLINS. SNOW SHOWERS DEVELOPING ON RIVERTON RADAR AND WEBCAMS
SHOWING LOWERING CONDITIONS WEST OF RAWLINS. DO THINK THERE IS A
PERIOD...SAY 03Z TO MAY 09Z WHERE KRWL COULD GO IFR IN LOW
CEILINGS AND SNOW. LATEST HRRR MODEL RUN CONFIRMS THIS CONCERN AND
EVEN BRINGS IFR CONDITIONS INTO KLAR AND KCYS. WILL CONTINUE TO
MONITOR...BUT CONFIDENCE IS HIGH ENOUGH TO KEEP LOW CONDITIONS OUT
OF THE KCYS TAF FOR NOW. KLAR MAY SEE LOWER CONDITIONS AFTER 06Z
AND WILL REEVALUATE FOR THE 06Z TAFS.

CLAYCOMB

.PREV DISCUSSION... /ISSUED 359 PM MST SUN FEB 17 2013/

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM/AVIATION...RJM

AREA FORECAST DISCUSSION

NWS GOODLAND KS

1015 PM MST SUN FEB 17 2013

.UPDATE...
ISSUED AT 915 PM MST SUN FEB 17 2013

HAVE DEBATED BACK AND FORTH THE PAST FEW HOURS WHETHER OR NOT TO
KEEP THE WIND ADVISORY GOING OR CANCEL IT. GIVEN THE BORDERLINE
NATURE OF POTENTIAL GUSTS TO 45 MPH AND THE ISOLATED NATURE THAT
THESE GUSTS COULD OCCUR FELT THE BEST COURSE OF ACTION WAS TO
CANCEL IT.

AT 0420Z COLD FRONT HAD PUSHED THROUGH THE NORTHWEST 1/3 OR SO OF
THE AREA WITH NORTHWEST WINDS GUSTING 30 TO 40 MPH. THIS MATCHES
WELL WITH 3 HOUR PRESSURE RISES OF 4-8MB. THIS AXIS OF STRONGER
PRESSURE RISES WILL SLOWLY SPREAD EAST/SOUTHEAST BEHIND THE FRONT
THROUGH THE REMAINDER OF THE NIGHT INTO EARLY MONDAY MORNING. FELT
20 TO 30 MPH WINDS WITH GUSTS OF 40 MPH WAS BETTER SUITED TO THE
SITUATION VS AN ADVISORY.

OTHER ADJUSTMENTS WERE TO FINE TUNE THE TEMPS/DEWPOINTS BOTH AHEAD
OF AND BEHIND THE FRONT AND BEEF UP CLOUD COVER TONIGHT.

UPDATE ISSUED AT 508 PM MST SUN FEB 17 2013

HAVE CANCELLED THE RED FLAG WARNING AS WINDS HAVE REMAINED WELL
BELOW THRESHOLDS.

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1015 PM MST SUN FEB 17 2013

VFR CONDITIONS EXPECTED THROUGH THE PERIOD AT KGLD AND KMCK.
NORTHWEST WINDS 25G35KTS WILL BE COMMON THROUGH MUCH OF THE PERIOD
BEFORE DECREASING AROUND 00Z THEN QUICKLY FALLING INTO THE 5-10KT
RANGE BY 01-02Z. CLOUDINESS WILL INITIALLY REMAIN LIMITED TO
CIRRUS LEVEL BUT WILL LOWER BEHIND THE FRONT AND CONTINUE THROUGH
THE DAY MONDAY. HOWEVER...AT THIS TIME THE LOWER CLOUD HEIGHTS
WILL NOT IMPACT FLIGHT CATEGORIES SO WILL NOT DETAIL IN TAF FOR
EITHER SITE.

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

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

AREA FORECAST DISCUSSION

NWS GOODLAND KS

921 PM MST SUN FEB 17 2013

.UPDATE...
ISSUED AT 915 PM MST SUN FEB 17 2013

OTHER ADJUSTMENTS WERE TO FINE TUNE THE TEMPS/DEWPOINTS BOTH AHEAD
OF AND BEHIND THE FRONT AND BEEF UP CLOUD COVER TONIGHT.

UPDATE ISSUED AT 508 PM MST SUN FEB 17 2013

HAVE CANCELLED THE RED FLAG WARNING AS WINDS HAVE REMAINED WELL
BELOW THRESHOLDS.

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 400 PM MST SUN FEB 17 2013

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

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

AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

247 AM CST MON FEB 18 2013

.DISCUSSION...

MAIN FORECAST CHALLENGE/CONCERN IS THE LACK OF DEEP MOISTURE
ACROSS MOST OF THE FA TODAY...OR AT LEAST UNTIL THIS AFTN...AND
MAINLY AFFECTING WC WI. SATELLITE IMAGERY INDICATED THAT THE MAIN
SOURCE OF GULF MOISTURE IS STILL ACROSS THE SOUTHERN MISSISSIPPI
VALLEY REGION AS OF 2 AM. THIS MOISTURE SOURCE WAS EXPECTED TO BE
ACROSS NORTHERN MO AT THIS TIME BASED ON EARLIER MODEL RUNS.
ALTHOUGH MOISTURE ACROSS ND HAS INCREASED OVER THE PAST 6
HRS...THIS AREA WILL LIKELY ONLY AFFECT N MN AS THE MAIN SHRTWV
MOVES ACROSS WC...INTO NE MN LATER TODAY. EVEN SOME OF THE SHORT
TERM MODELS INDICATED VERY LITTLE RADAR RETURNS AS THE MAIN COLD
FRONT MOVES THRU THIS MORNING. IT IS NOT UNTIL ARND 18Z THAT ANY
TYPE OF SIGNAL TRANSLATES INTO LIGHT PRECIPITATION DEVELOPING
ACROSS THE FAR EASTERN FA. BASED ON THESE PARAMETERS...AND THE
LACK OF UPPER LEVEL FORCING...HIGHER POPS WILL BE CONFINED TO WC
WI. WILL MONITOR RADAR RETURNS OVER THE NEXT TWO HRS AND SEE ANY
SIGNS OF DEVELOPMENT ACROSS IA...TO CHG MY PRESENT SCENARIO OF CHC
POPS FOR MOST OF THE FA...WITH THE EXCEPTION OF WC WI. THE OTHER
FORECAST CONCERN IS THE STRONG WINDS DEVELOPING IN ON THE BACK
SIDE OF THIS COLD FRONT WHICH IS EXPECTED TO MOVE THRU THE FA BY
21Z. SEVERAL LOCAL MODELS HAVE INDICATED A VERY STRONG SIGNAL OF
WIND SPDS OF 30 TO 35 MPH...WITH GUSTS OVER 45 MPH ACROSS WC/SW
AND SC MN LATER TODAY...AND INTO THIS EVENING. BASED ON THE
ALREADY DEEP SNOW COVER IN THE WEST...WILL CONTINUE THE WINTER WX
ADVISORY FOR BLOWING SNOW...WITH SOME LIGHT SNOW...BUT NOT
EXPECTING ANYTHING ON ADDITIONAL ACCUMULATIONS. AREAS IN SC MN
WHERE SNOW COVER IS ALMOST NON-EXISTENT...WILL GO WITH A WIND
ADVISORY. THIS SYSTEM QUICKLY DEPARTS THE AREA BY TUESDAY
MORNING...WITH A QUIET PERIOD UNTIL LATE WED/EARLY THURSDAY AS THE
NEXT WEATHER SYSTEM BEGINS TO AFFECT THE REGION. DURING THIS
TIME...TEMPS WILL LIKELY AVERAGE 10 TO 20 DEGREES BELOW NORMAL.

FOR THE WEATHER SYSTEM LATE IN THE WEEK...MODELS HAVE BEEN
CONSISTENT ON PRECIPITATION DEVELOPING BY LATE WED/EARLY THURSDAY
ACROSS SW MN...AND SLOWLY SPREADING N/NE ACROSS THE FA THRU
FRIDAY. AS WITH PREVIOUS DISCUSSIONS...THIS SYSTEM WEAKENS AS IT
MOVES NORTHEAST ACROSS THE PLAINS...AND INTO THE UPPER MIDWEST.
MODELS HAVE ALSO INDICATED THAT THE BULK OF THE GULF MOISTURE WILL
TRANSLATE FROM THE CENTRAL PLAINS...INTO THE MID MISSISSIPPI
VALLEY BY THU/FRI. THIS WILL LEAD TO MAINLY A LARGE WARM AIR
ADVECTION PATTERN ACROSS THE UPPER MIDWEST WITH A WEAKENING TREND
AS THE SYSTEM MOVES NE. BASICALLY THIS WILL LEAD TO THE HIGHEST
QPF AMTS ACROSS KANSAS/NEBRASKA/IOWA THRU THURSDAY MORNING. AS IT
MOVES ACROSS NORTHERN IA...AND INTO SOUTHERN MN...QPF AMTS WILL
DECREASE AS PER THE CUT OFF OF THE DEEPER GULF OF MEXICO MOISTURE
TO THE EAST. ALTHOUGH THERE WILL BE A PROLONGED PERIOD OF LIGHT
SNOW...GENERALLY SNOWFALL TOTALS THRU FRIDAY MORNING AS THE SYSTEM
RINGS ITSELF OUT...WILL TRANSLATE TO LOCALLY 6 TO 8 INCHES ALONG
THE IOWA BORDER...TO 3 TO 6 INCHES ACROSS THE REST OF THE
FA...WITH THE LEAST AMTS ACROSS CENTRAL MN. ALTHOUGH STRONG WINDS
WILL ACCOMPANY THE BEGINNING OF THIS SYSTEM...THE WIND SPDS WILL
LIKELY DECREASE BY THURSDAY AFTN/EVENING AS THE LOW WEAKENS.

PAST FRIDAY...ANOTHER WINTER STORM IS PROGGED TO MOVE INTO THE
CENTRAL PLAINS BY LATE IN THE WEEKEND. IT IS TOO EARLY TO TELL IF
SIGNIFICANT SNOW WILL FALL ACROSS THE UPPER MIDWEST...BUT WITH
THIS ACTIVE PATTERN CONTINUING...THIS FEBRUARY COULD END UP WITH
MORE SNOWFALL THAN AVERAGE. ..JLT..

.AVIATION... /06Z TAF ISSUANCE/

COLD FRONT JUST MOVING INTO WRN MN AT 530Z AND WILL BE MOVING
THROUGH RWF/AXN BY 9Z...MSP AROUND 12Z...AND EAU AROUND 17Z. VERY
DRY AIR AHEAD OF THE FRONT MEANS ANY MVFR CONDS OR LOWER WILL HAVE
TO WAIT UNTIL AFTER THE COLD FRONT PASSES. AS A RESULT DELAYED
MVFR CIGS A COUPLE OF MORE HOURS FROM WHAT 00Z TAFS HAD AND
REMOVED FZDZ MENTION FROM WRN WI. AS FOR SNOW POTENTIAL...STRONG
CAA DURING THE MORNING WILL PRIME THE ATMO FOR -SHSN BY THE
AFTERNOON...BUT 00Z NAM/GFS ALONG WITH THE RAP SHOW A BAND OF SNOW
DEVELOPING IN THE MORNING IMMEDIATELY BEHIND THE FRONT. THIS LOOKS
TO FORM RIGHT OVER MSP AND MOVE IN TO WRN WI. SHOULD PROVIDE A
QUICK BURST OF HEAVIER SNOW WITH VIS GETTING DOWN TO OR A LITTLE
LESS THAN A MILE FROM MSP EAST. OTHER THAN THAT THE COMBO OF
STRONG NW WINDS AND OCCASIONAL -SHSN SHOULD PROMOTE A PROLONGED
PERIOD OF 2-6SM VSBYS AT MOST TERMINALS FROM THE AFTERNOON INTO
THE EVENING. AS FOR THOSE WINDS...TIMED THE DIRECTION CHANGE ON A
HRRR/LAMP BLEND. MIX POTENTIAL FROM THE NAM/GFS HAS NOT CHANGED AT
ALL WITH 00Z RUNS...WITH TOP OF THE CHANNEL WINDS STILL AROUND 35
KTS ACROSS MN FROM ABOUT 21Z RIGHT THROUGH THE REST OF THE NIGHT.

KMSP...FIRST ISSUE WILL BE WIND SHIFT DURING THE MORNING. SPEEDS
MAY BE UNDER 7 KTS BY 10Z...ALLOWING FOR SOME LEE WAY ON RUNWAY
CONFIGURATION...WITH NW WINDS EXPECTED TO DOMINATE FROM ABOUT 15Z
ON. FOR SNOW...NAM/GFS/RAP SHOWING A POST FRONTAL BAND OF SNOW
DEVELOPING IN THE LATE MORNING AND WILL BE A CLOSE CALL FOR
MSP...WITH HIGHER PROBABILITIES OF IT OCCURRING BEING EAST OF THE
FIELD. IF MSP SEES IT...WOULD BE A QUICK 1/2 TO 1 INCH OF SNOW IN
A COUPLE OF HOURS. AFTER THAT...MUCH OF THE AFTERNOON THROUGH THE
NIGHT WILL BE DOMINATED BY PERIODS OF SNOW SHOWERS AND BLSN...WITH
VIS FLUCTUATING BETWEEN IFR AND VFR LEVELS FOR MUCH OF THE TIME.
FOR CIGS...EXPECT MVFR CIGS TO MOVE IN BETWEEN 13Z AND 15Z. MAY
INITIALLY BE ABOVE 1700...BUT SHOULD SETTLE BELOW THAT LEVEL BY
THE AFTERNOON...PERSISTING THERE THROUGH MUCH OF THE NIGHT.

/OUTLOOK FOR KMSP/

TUE...MVFR CIGS POSSIBLE. WINDS NW AT 15 TO 25
KTS DECREASING TO 10 TO 20 KTS.
WED...VFR. WINDS NW TO E AOB 5 KTS.
THU...VFR MORNING. IFR OR LOWER WITH SNOW AFTERNOON/NIGHT. WINDS E
AT 15 KTS.

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR BROWN-CARVER-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-
MCLEOD-MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEARNS-
STEVENS-SWIFT-TODD-WRIGHT-YELLOW MEDICINE.

WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-LE SUEUR-MARTIN-STEELE-WASECA-
WATONWAN.

WI...NONE.
&&

JLT/MPG

AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

1156 PM CST SUN FEB 17 2013

.UPDATE...

06Z AVIATION DISCUSSION ADDED BELOW.

.PREV DISCUSSION...
/ISSUED 545 PM CST SUN FEB 17 2013/

TWO SIGNIFICANT WEATHER IMPACTS EXPECTED THIS WEEK ACROSS THE
REGION. THE FIRST WILL BE ASSOCIATED WITH A POWERFUL COLD FRONT
THAT IS EXPECTED TO MOVE DOWN FROM THE DAKOTAS TOMORROW AND USHER
IN ANOTHER BLAST OF ARCTIC AIR. THE SECOND WILL BE A SIGNIFICANT
WINTER STORM THAT IS FORECAST TO EMERGE ACROSS THE SOUTHWESTERN
US...AND SPREAD HEAVY SNOW ACROSS THE CENTRAL PLAINS UP THROUGH
THE GREAT LAKES REGION THURSDAY AND FRIDAY.

TODAY THROUGH WEDNESDAY...EARLY AFTERNOON NORTHERN HEMISPHERIC WATER
VAPOR TOGETHER WITH GFS 500MB HEIGHTS AND WINDS SHOWED AN ACTIVE
PATTERN WITH 3 DISTINGUISHED LONGWAVE TROUGHS. FROM EAST TO
WEST...THE FIRST WAS ASSOCIATED WITH THE NOREASTER OFF THE NEW
ENGLAND COAST...THE SECOND LOCATED WAS OVER MONTANA...AND THE THIRD
WAS FURTHER UPSTREAM IN THE GULF OF ALASKA. A CLOSER LOOK AT THE
MIDDLE WAVE REVEALS AN EMBEDDED VORT MAX UPSTREAM OF THE TROUGH AXIS
IN WESTERN ALBERTA ALONG THE POLEWARD SIDE OR THE SOUTHWARD MOVING
JET DRIVEN BY THE SPEED SHEAR. A SECOND VORT MAX WAS CENTERED OVER
MONTANA NEAR THE BASE OF THE TROUGH EXISTING MAINLY DUE TO THE
CURVATURE OF THE FLOW. AT THE SURFACE A 998MB SURFACE LOW WAS
CENTERED ACROSS THE NORTH DAKOTA/CANADA BORDER. AS TIME
PROGRESSES...NUMERICAL MODELS AGREE THAT THE MONTANA SHORTWAVE WILL
GAIN STRENGTH AS THE AFOREMENTIONED UPSTREAM UPPER LEVEL JET ROUNDS
THE BASE OF THE TROUGH. TONIGHT THE SURFACE LOW WILL PROPAGATE
EASTWARD IN CONCERT WITH THE UPPER LEVEL FORCING AND SHOULD BE
LOCATED IN NORTHERN MINNESOTA BY MONDAY MORNING. AHEAD OF THIS
SURFACE LOW WARM AIR ADVECTION WILL LIFT ACROSS SOUTHEAST MINNESOTA
AND WESTERN WISCONSIN CAUSING CLOUDS TO FORM AND POSSIBLY SOME LIGHT
FREEZING DRIZZLE...BUT DID NOT HAVE THE CONFIDENCE TO ISSUE ANY
HEADLINES. MEANWHILE FURTHER WEST...STRONG COLD AIR ADVECTION WILL
FOLLOW IN THE WAKE OF THE TRAILING COLD FRONT ACROSS WESTERN
MINNESOTA MONDAY MORNING. AS IT DOES...FORECAST SOUNDINGS SHOW THE
BOUNDARY LAYER QUICKLY DESTABILIZING WITH FALLING TEMPERATURES IN TO
THE TEENS ACROSS WESTERN MINNESOTA BY NOON...AND SINGLE DIGITS BY
EARLY EVENING. BOTH THE NAM AND GFS 17.12 BUFR SOUNDINGS SHOW
SEVERAL HOURS OF 35-40KTS ATOP THE MIXED LAYER...WITH A SOLID 30KTS
SUSTAINED. THE DENDRITIC ZONE ALSO BECOMES SATURATED IN THE LOWEST
10000FT. BOTH OF THESE WOULD SUPPORT BLOWING SNOW AND REDUCED
VISIBILITIES MONDAY AFTERNOON AND EVENING. HOWEVER...THE BEST
FORCING WILL BE ALONG THE MN/CANADA BORDER...WITH LITTLE OMEGA SOUTH
OF THIS. THEREFORE HAVE RULED OUT BLIZZARD CONDITIONS. THE QUESTION
THEN BECOMES WIND ADVISORY OR WINTER WEATHER ADVISORY. STRONG WIND
AND FALLING TEMPERATURES ARE A LOCK TO OCCUR WITH THE FRONTAL
PASSAGE...BUT THE WILD CARD IS THE SNOW AMOUNTS. SINCE THE POTENTIAL
IS THERE...HAVE DECIDED TO GO WITH WINTER WEATHER ADVISORY WITH
STRONG WIND WORDING SINCE THIS IMMEDIATELY GIVES THE PUBLIC THE
PERCEPTION THAT TRAVEL WILL BE IMPACTED MONDAY EVENING. CONFIDENCE
IS HIGH THAT SNOW AMOUNTS WILL REMAIN LESS THAN 3 INCHES...BUT
HOLISTIC REASONING SUPPORTS A HEADLINE...AND FEEL THE WINTER WEATHER
ADVISORY IS THE BEST APPROACH AT THIS TIME ENDING AT MIDNIGHT. WIND
CHILL ADVISORIES WILL LIKELY BE NEEDED FOLLOWING THE WINTER WEATHER
ADVISORY...BUT THIS SHOULD BE A SMOOTH TRANSITION MONDAY NIGHT. ON
TUESDAY AND WEDNESDAY A HIGHLY AMPLIFIED UPPER LEVEL RIDGE WILL
CAUSE SURFACE HIGH TO DEVELOP ACROSS CENTRAL NORTH AMERICA WITH
TEMPERATURES STRUGGLING TO GET OUT OF THE SINGLE DIGITS FOR HIGHS ON
TUESDAY...AND LOWER TEENS ON WEDNESDAY.

THURSDAY THROUGH SUNDAY...NEXT SYSTEM THAT COULD BRING SIGNIFICANT
SNOWFALL ACROSS THE REGION FOR THURSDAY AND FRIDAY IS THE TROUGH
CURRENTLY OVER THE GULF OF ALASKA. FORECAST MODELS SHOW TWO EMBEDDED
SHORTWAVES WITHIN THIS TROUGH PHASING TOGETHER AND MOVING SOUTH
PARALLELING THE WEST COAST. AS THE SYSTEM EMERGES OUT OF THE DESERT
SOUTHWEST BY MIDWEEK A POWERFUL CYCLONE IS FORECAST TO DEVELOP ON
THE FRONT RANGE OF EASTERN COLORADO...WITH SIGNIFICANT SNOW POSSIBLE
IN NORTHEAST COLORADO WEDNESDAY NIGHT. AS THE STORM DEVELOPS ON
THURSDAY IT WILL TAKE BECOME VERTICALLY STACKED...CAUSING THE
SURFACE CYCLONE TO GRADUALLY FILL THROUGHOUT THE THE DAY AS THE
UPPER LEVEL FORCING OUTRUNS ITS SURFACE COUNTERPART. BY THURSDAY
EVENING THIS MATURE CYCLONE WILL HAVE A WELL DEFINED TROWEL ON THE
NORTHEASTERN SIDE OF THE 500MB LOW...WITH A BROAD AREA OF MODERATE
SNOW EXPECTED TO BE ONGOING ACROSS THE MN/WI REGION...WHICH SHOULD
PUSH NORTHWARD THURSDAY NIGHT. UNLIKE THE LAST STORM...THE THERMAL
PROFILES CLEARLY INDICATE ALL SNOW...SO FORTUNATELY THAT IS ONE LESS
VARIABLE TO WORRY ABOUT. ALSO...WINDS/BLOWING SNOW SHOULD NOT BE
MUCH OF AN ISSUE EITHER. FOR NOW HAVE INCREASES POPS TO THE HIGH
CATEGORICAL WELL ABOVE MODEL GUIDANCE...AND WILL WAIT WITH ANY
HEADLINE DECISION UNTIL CLOSER TO THE EVENT.

.AVIATION.../06Z TAF ISSUANCE/

/OUTLOOK FOR KMSP/
TUE...MVFR CIGS POSSIBLE. WINDS NW AT 15 TO 25 KTS DECREASING TO 10
TO 20 KTS.
WED...VFR. WINDS NW TO E AOB 5 KTS.
THU...VFR MORNING. IFR OR LOWER WITH MOD/HEAVY SNOW
AFTERNOON/NIGHT. WINDS E AT 15 KTS.

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM NOON MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR BROWN-CARVER-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI
PARLE-MCLEOD-MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-
STEARNS-STEVENS-SWIFT-TODD-WRIGHT-YELLOW MEDICINE.

WI...NONE.
&&

JRB/MPG

AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

345 AM CST MON FEB 18 2013

.SHORT TERM...(TODAY AND MONDAY)
WIND ADVISORY TODAY...ALONG AND EAST OF HIGHWAY 20. AN ARCTIC
FRONT...CURRENTLY ENTERING NW SD AT 08Z...WILL DRAPE NORTHWEST TO
SOUTHEAST FROM ROUGHLY KIEN-KAIA TO KBBW. AS LOW PRESSURE ACROSS
ND THIS MORNING MOVES EAST INTO THE NRN GREAT LAKES
TONIGHT...ARCTIC HIGH PRESSURE WILL RIDGE SOUTH PART WAY INTO THE
FCST AREA.

THE FCST FOLLOWS A BLEND OF MODEL DATA PRODUCING HIGHS IN THE LOWER
30S NORTH TO LOWER 40S SOUTH. LOWS TONIGHT...SINGLE DIGITS
NORTH...TEENS SOUTH BUT MET MAV GUIDANCE IS COLDER.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
SFC WINDS WILL BECOME SOUTHEAST AND INCREASE BY TUESDAY
AFTERNOON...AS LOW PRESSURE DEVELOPS TO OUR WEST IN RESPONSE TO
THE APPROACHING STORM SYSTEM. SOME ARCTIC AIR WILL FILTER BACK
WEST INTO THE AREA THROUGH THE DAY...WITH HIGHS ONLY IN THE 20S
ACROSS EASTERN PORTIONS OF NORTH CENTRAL NEBRASKA AROUND
ONEILL...TO LOWER 40S FAR SOUTHWEST NEBRASKA.

CONFIDENCE HAS INCREASED FROM 24 HRS AGO IN REGARDS TO THE POTENTIAL
WINTER STORM WEDNESDAY NIGHT AND THURSDAY. MODELS/ENSEMBLES HAVE
FINALLY CONVERGE ON A TRACK...WITH THE OPERATIONAL GFS AND ECMWF
VERY SIMILAR IN TRACKING THE UPPER PART OF THE SYSTEM FROM WESTERN
KANSAS TO NORTHEAST NEBRASKA. THIS IS HISTORICALLY A FAVORABLE TRACK
FOR WESTERN AND NORTH CENTRAL NEBRASKA TO RECEIVE SNOWFALL. EVEN THE
NAM AND SREF ARE ONBOARD...AND IT IS LOOKING LIKE MUCH OF WESTERN
AND NORTH CENTRAL NEBRASKA WILL RECEIVE SUBSTANTIAL SNOW
ACCUMULATION WEDNESDAY THROUGH THURSDAY. A LEAD SHORTWAVE WILL
PRECEDE THE SYSTEM TUESDAY NIGHT INTO WEDNESDAY...AND THAT REALLY
GETS THE SOUTHERLY LOW LEVEL JET CRANKED UP RETURNING GULF MOISTURE
NORTHWARD INTO THE SOUTHERN AND EVENTUALLY CENTRAL PLAINS. GOOD
ISENTROPIC UPGLIDE AND A GRADUALLY MOISTENING ATMOSPHERE SHOULD
ALLOW FOR AT LEAST SCATTERED AREAS OF LIGHT SNOW TO DEVELOP BY
WEDNESDAY AFTERNOON. WON/T GO TOO HIGH WITH POPS WEDNESDAY AS WE
WILL BE FIGHTING SOME DRY AIR IN THE MID LEVELS OF THE ATMOSPHERE.
THIS MID LEVEL DRY AIR IS GONE BY WEDNESDAY NIGHT...AND THIS IS WHEN
THINGS START TO GET INTERESTING. THIS SYSTEM APPEARS TO HAVE ALL
FACETS OF A CLASSIC CENTRAL/SOUTHERN PLAINS WINTER STORM. THAT
INCLUDES T-STORMS TO OUR SOUTH AND SOUTHEAST...AS WELL AS FREEZING
RAIN IN PORTIONS OF THOSE AREAS. NOT EXPECTING ANY FREEZING
PRECIPITATION IN OUR AREA...AS SOUNDINGS INDICATE A COLD ENOUGH
ATMOSPHERE FOR ALL SNOW. AS FAR AS THE T-STORM ACTIVITY GOES...IT IS
ALWAYS A CONCERN WHEN STORMS BLOW UP ACROSS THE SOUTHERN
PLAINS...AND FROM ALL INDICATIONS THERE WILL BE CONVECTION.
FORTUNATELY THIS SYSTEM HAS A STRONG NEGATIVE TILT...AND MOISTURE
TRANSPORT CONTINUES THROUGH WEDNESDAY NIGHT INTO OUR AREA DESPITE
SOUTHERN PLAINS CONVECTION. THE MOISTURE TRANSPORT DOES WANE
THURSDAY MORNING...AND SNOW SHOULD BEGIN TAPERING OFF SOMEWHAT BY
AFTERNOON. WE WILL KEEP AN EYE ON THE MODELS THE NEXT FEW RUNS
REGARDING THE CONVECTION TO OUR SOUTH...BUT FOR NOW NOT SEEING ANY
SIGNS OF THE CONVECTION DISRUPTING THE MOISTURE FLOW ENOUGH TO
MITIGATE OUR SNOW POTENTIAL. SNOW SHOULD BE HEAVIEST ACROSS OUR AREA
FROM ABOUT MIDNIGHT WEDNESDAY NIGHT THROUGH NOON THURSDAY. THIS IS
WHEN Q-VECTOR CONVERGENCE IS MAXIMIZED ACROSS OUR AREA...AND THIS IS
ALSO THE PERIOD WE TRANSITION FROM A SOUTHERLY WARM AIR ADVECTION
FLOW ALOFT...TO A DEFORMATION BAND AS THE SYSTEM BEGINS TRACKING
NORTHEAST FROM WESTERN KS INTO CENTRAL NEBRASKA. AS THE SYSTEM
CONTINUES TRACKING NORTHEAST THURSDAY AFTERNOON THE DEFORMATION BAND
ON IT/S WESTSIDE ACROSS OUR AREA WILL BEGIN WEAKENING. SNOW BY
THURSDAY EVENING WILL BE VERY LIGHT...PROBABLY NON
ACCUMULATING...AND SHOULD BE COMPLETELY DONE LATE THURSDAY NIGHT.

AS FAR AS AMOUNTS...GENERALLY THINKING 8 TO 12 INCHES ALONG AND EAST
OF HIGHWAY 83...WITH 5 TO 10 INCHES TO THE WEST OF HWY 83 BY THE
TIME THE STORM WINDS DOWN THURSDAY NIGHT.

STILL NOT LOOKING THAT WINDY WITH THIS SYSTEM. MOST MODELS SUPPORT A
GENERAL 15 TO 20 MPH SUSTAINED WIND WITH GUSTS TO 25 MPH OR SO. THIS
WILL STILL CREATE SOME BLOWING AND DRIFTING...BUT A BLIZZARD DOES
NOT LOOK LIKE IT IS IN THE CARDS WITH THIS SYSTEM.

QUITE COLD IN THE WAKE OF THIS SYSTEM...WITH THE EXPECTED SNOW COVER
AND LINGERING ARCTIC AIR. THE ECMWF IS ADVERTISING ANOTHER INTENSE
WINTER STORM SUNDAY INTO MONDAY...WITH THE GFS AND ENSEMBLES HINTING
AT THIS. MODELS SO FAR HAVE BEEN VERY CONSISTENT WITH THE TRACK OF
THIS FIRST SYSTEM...EVEN WHILE OUT OVER THE PACIFIC. THE SECOND
SYSTEM APPEARS TO TAKE A VERY SIMILAR TRACK ACROSS THE PACIFIC...SO
WILL HAVE TO WATCH THE MODELS VERY CLOSELY THE NEXT FEW DAYS TO SEE
IF THEY ALL LATCH ON. FOR NOW WILL CONTINUE THE LOW CHANCE POPS ON
SUNDAY TO ACCOUNT FOR THIS POTENTIAL SECOND ROUND OF WINTER
WEATHER.

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
MVFR CIGS ALONG HIGHWAY 20 COULD SPREAD TO NEAR I-80 BY MORNING
ACCORDING TO THE RAP MODEL. THE OTHERS HANG THE STRATUS ALONG
HIGHWAY 20 ALL DAY AND OVERNIGHT MONDAY NIGHT. MIDLEVEL CLOUDS ARE
BLOCKING THE VIEW OF THESE LOWER CLOUDS ON SATELLITE SO THE FCST
SOUTH OF KVTN IS UNCERTAIN. EITHER WAY...IF CIGS GET TO KLBF THEY
SHOULD LIFT BY 20Z. IN THE PAST THE RAP HAS BEEN THE BEST FOR THIS
FEATURE SO VFR IS EXPECTED AT KLBF FOR NOW.

FOR TONIGHT...MONDAY NIGHT...WE WILL HOLD THE STRATUS/MVFR UP ALONG
HIGHWAY 20 UNTIL WE GET SOME FEEDBACK ON THE RAP MODEL FCST.

.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING TO 6 PM CST
/5 PM MST/ THIS EVENING FOR NEZ005>010-024>029-036>038-059-071.

SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC

AREA FORECAST DISCUSSION...UPDATED

NWS GRAND FORKS ND

1017 PM CST SUN FEB 17 2013

.DISCUSSION...CHALLENGES INCLUDE HOW FAR SOUTH BLIZZARD
CONDITIONS WILL OCCUR AND SNOW AMOUNTS ACROSS THE NORTHERN FA.

SNOW AMOUNTS...SNOWFALL RATES OF AROUND 1 INCH PER HOUR OCCURRING
ACROSS THE NORTHERN FA AND 00Z NAM/GFS AGREE WITH BANDING
POTENTIAL FOR THIS AREA. GIVEN CURRENT SNOWFALL RATES AND HI-RES
MODEL QPF VALUES (WHICH ARE BETTER SINCE THEY CATCH ONTO MESOSCALE
FORCING) WILL INCREASE TOTAL SNOW AMOUNTS INTO THE 6-10 INCH RANGE
FOR THE LANGDON...HALLOCK...ROSEAU...AND BAUDETTE AREA...WITH 2-5
INCHES FURTHER SOUTH. GIVEN TRACK OF MID-LEVEL LOW...AREAS SOUTH
OF HIGHWAY TWO WILL RECEIVE VERY LITTLE SNOWFALL.

BLIZZARD CONDITIONS...BLIZZARD CONDITIONS WILL OCCUR WHERE THERE
IS FRESH SNOWFALL (BLIZZARD WARNING AREA). THIS AREA WILL LIKELY
EXPERIENCE THE STRONGEST WINDS AS MODELS INDICATE 925MB WINDS
AROUND 45 KNOTS HERE. FURTHER TO THE SOUTH...WHERE ONLY A DUSTING
OF SNOW IS EXPECTED...TEMPERATURES ARE CURRENTLY IN THE LOW 30S.
THIS IS CAUSING THE SNOWPACK TO BECOME MORE DENSE...ESPECIALLY THE
TOP LAYER. 925MB WINDS A BIT WEAKER TO THE SOUTH...AND THESE
FACTORS COMBINED MAY BE ENOUGH TO PREVENT WIDESPREAD BLIZZARD
CONDITIONS. THUS...HAVE CHANGED THE WATCHES TO ADVISORIES. THE
MAIN THING TO WATCH FOR ON MONDAY WILL BE INTENSITY OF SNOW
SHOWERS...AS STRONGER SNOW SHOWERS COMBINED WITH THE STRONG WINDS
COULD PRODUCE WHITEOUT CONDITIONS.

.AVIATION...FOCUS TONIGHT INTO MONDAY WILL BE TIMING OF WIND
SHIFT AND THEN VSBY/CIGS WITH SNOW EXPECTED ESP DVL-GFK-TVF
REGIONS. BASED WIND CHANGE AND SNOW TIMING ON RAP MODEL WITH
STRONG WINDS NOT HITTING TIL A FEW HOURS AFTER FRONTAL PASSAGE.
VSBYS AND CIGS MONDAY MAY BE QUITE VARIABLE BUT GENERALLY IFR DVL-
GFK-TVF IN BLSN...FARGO-BJI A MIX OF MVFR AND IFR MAINLY DUE TO
VSBYS. WINDS IN THE RED RIVER VALLEY AND DVL REGION WILL GUST TO
40 KTS OR HIGHER AT TIMES MONDAY WITH 25 TO 30 KTS PSBL MON AFTN
IN BEMIDJI.

PREV DISCUSSION... /ISSUED 319 PM CST SUN FEB 17 2013/

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR NDZ038-
039-049-052-053.

BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR NDZ016-024-
026>030.

BLIZZARD WARNING UNTIL 6 PM CST MONDAY FOR NDZ006>008-014-015-
054.

MN...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR MNZ002-
003-015>017-022-027-029>031-040.

BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR MNZ001-004-007.

WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR MNZ005-006-008-
009-013-014.

$$
TG

AREA FORECAST DISCUSSION

NWS NASHVILLE TN

1129 PM CST SUN FEB 17 2013

.UPDATE...FOR 06Z AVIATION FORECAST

AVIATION INTERESTS CAN EXPECT VERY GUSTY WINDS ON MONDAY WITH
SOME GUSTS AS HIGH AS 35 KNOTS AS A TIGHT SURFACE PRESSURE GRADIENT
WILL EXIST ACROSS THE TENNESSEE VALLEY ALONG WITH A GOOD DOWNWARD
TRANSPORT OF LOW LEVEL WINDS TO THE SURFACE AS INDICATED BY LOW
LEVEL THETA SURFACES.

I DONT THINK SHOWERS WILL REACH THE TENNESSEE RIVER UNTIL AFTER
00Z AS BOTH NAM AND GFS ALONG WITH THE SREF ARE VERY CLOSE TO THIS
TIMING WITH SHOWER ACTIVITY INCREASING RATHER QUICKLY FROM WEST TO
EAST ACROSS MIDDLE TENNESSEE AFTER 00Z.

SYSTEM IS PROGRESSIVE AND WILL BEGIN TO END FROM THE WEST NEAR THE
TENNESSEE RIVER BY 12Z WITH RAIN ENDING MOST AREAS OF THE MID
STATE BY 18Z.

BOYD

.PREV DISCUSSION... /ISSUED 928 PM CST SUN FEB 17 2013/

UPDATE...
ONGOING FORECAST LARGELY IN LINE AT THIS TIME. WEAK SFC HIGH
TOWARD TYS WILL CONTINUE TO SLOWLY PUSH EAST OVERNIGHT...ALLOWING
GRADIENT TO TIGHTEN. THIS SMALL KICK IN WIND ALONG WITH SOME HIGH
CLOUDS SPREADING OVER SHOULD KEEP TEMPERATURES FROM REALLY
BOTTOMING OUT. WILL HOWEVER KNOCK DOWN A FEW DEGREES PLATEAU WHERE
IT HAS REALLY COOLED OVER LAST FEW HOURS.

LATEST AVAILABLE DATA STILL PEGGING TOMORROW NIGHT FOR MAIN BRUNT
WITH INCOMING COLD FRONT. WINDS AHEAD DURING THE AFTERNOON MAY
GUST 35-40MPH BUT WILL HOLD OFF ON AN ADVISORY FOR NOW.

PREV DISCUSSION... /ISSUED 537 PM CST SUN FEB 17 2013/

UPDATE...FOR 00Z AVIATION FORECAST

AVIATION...
GOOD WARM ADVECTION THROUGH THE 6K-10K LAYER AS EVIDENT BY BROKEN
ALTOCU AND LATEST RUC RUN.

I KEPT VFR CONDITIONS FOR NEXT 24 HOURS WITH ONLY A SMALL POP
CHANCE AT CLARKSVILLE`S TERMINAL AFTER 21Z.

BOYD

PREV DISCUSSION... /ISSUED 318 PM CST SUN FEB 17 2013/

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

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

1145 PM CST SUN FEB 17 2013

.SHORT TERM...TONIGHT INTO MONDAY
602 PM CST SUN FEB 17 2013

AFTER A LOOK AT 00Z SOUNDING DATA AND ADDITIONAL RAP AND PERHAPS
NAM DATA...WILL CONSIDER MAKING ADJUSTMENTS TO THE PRECIPITATION
TYPES AND CHANCES IN GENERAL FOR MONDAY.

IN SUMMARY...THE WINTRY MIX CONCERN FOR MONDAY LOOKS TO BE
DECREASING.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
257 PM CST SUN FEB 17 2013

.AVIATION...THROUGH 06Z TUESDAY
1145 PM CST SUN FEB 17 2013

A LOT GOING ON WITH THIS AVIATION FORECAST.

WINDS...THE PRESSURE GRADIENT IS STILL TIGHT AHEAD OF LOW
PRESSURE IN THE DAKOTAS. THE GRADIENT REALLY DOESNT RELAX UNTIL
TOWARDS 12Z. THUS...EXPECT KRST TO PERSIST WITH A SOUTHEAST 15-20
KT AND GUSTS OF 25-30KT. AT KLSE...THE VALLEY LOCATION RESULTS IN
LIGHTER SURFACE WINDS...AND WITH SOUTH SPEEDS AROUND 45 KT AT
1500-2000 FT...LOW LEVEL WIND SHEAR CONTINUES. EXPECT THE WIND
SHEAR TO END AS WELL TOWARDS 12Z AS THAT LOW LEVEL JET PUSHES OFF
TO THE EAST. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PUSH
THROUGH THE TAF SITES BETWEEN 15-19Z...SWINGING WINDS AROUND TO
THE NORTHWEST. AS COLD AIR RUSHES IN AND PRESSURES RISE...EXPECT
THE WINDS TO INCREASE AND GUST FOR THE AFTERNOON AND EVENING.
GUSTS OF 25-30 KT ARE POSSIBLE...STRONGEST IN THE EVENING. BOTH
TAF SITES LOOK SUSCEPTIBLE TO STRONG GUSTS AS THE LOW PRESSURE
SYSTEM DEEPENS AFTER IT PASSES.

CEILINGS...THE GFS AND NAM MODELS ARE STILL HAVING PROBLEMS
HANDLING MOISTURE IN THE LOWEST COUPLE THOUSAND FEET...AS
DISCUSSED IN THE SHORT TERM SECTION OF THE AFD ISSUED AT 602 PM ON
SUNDAY. THE 06Z TAFS AGAIN RELY MORE ON THE RAP/HRRR/NCEP HIRES-
ARW RUNS WHICH ARE DOING A MUCH BETTER JOB. THESE MODELS ALL
SUGGEST THAT LOW CLOUD POTENTIAL IS MUCH LESS...UNTIL THE COLD
FRONT COMES THROUGH. ALONG AND IN ITS WAKE...EXPECT MVFR CEILINGS
TO MOVE IN. THEY COULD EVEN BRIEFLY DROP TO IFR...BUT CONFIDENCE
IS NOT HIGH ENOUGH TO MENTION. PLUS...UPSTREAM OVER THE DAKOTAS
CEILINGS ARE MAINLY MVFR BEHIND THE FRONT. PLAN ON THE CEILINGS TO
RISE SLIGHTLY HEADING INTO THE EVENING.

VISIBILITY AND PRECIPITATION...THERE SHOULD BE A BAND OF SNOW
THAT FORMS IN THE WAKE OF THE COLD FRONT...NOW LOOKING LIKE IT
WILL FORM OVER KRST BY MID AFTERNOON...THEN SLIDE EAST-NORTHEAST
AND PERHAPS CLIP KLSE. INTRODUCED MVFR VISIBILITIES FOR KRST AND
KEPT THEM AT KLSE...WHICH EITHER SITE MAY NEED LOWERING WHEN
CONFIDENCE INCREASES ON THE PLACEMENT OF THE BAND. ASSUMING SOME
SNOW DOES OCCUR...THE WIND COMBINED WITH ADDITIONAL FALLING LIGHT
SNOW SHOULD RESULT IN BLOWING SNOW AT KRST FOR THE EVENING...
ENOUGH TO REDUCE VISIBILITIES AT LEAST TO MVFR. CONFIDENCE OF
BLOWING SNOW NOT AS HIGH AT KLSE...THUS VFR VISIBILITIES ARE
FORECAST THERE FOR THE EVENING.

.ARX WATCHES/WARNINGS/ADVISORIES...
257 PM CST SUN FEB 17 2013

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...AJ
LONG TERM...HALBACH
AVIATION...AJ

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

746 AM EST MON FEB 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST MON FEB 18 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS WITH SEVERAL EMBEDDED SHRTWVS. THE
MOST PROMINENT SHRTWVS OVER ERN ND AND WRN KS ALSO SUPPORTED SFC
LOWS INTO NRN MN AND CNTRL KS. SRLY FLOW HAD INCREASED OVER THE WRN
LAKES BTWN THE TROUGH TO THE WEST AND THE RIDGE THROUGH THE ERN
LAKES WITH KMQT/KGRB VAD WIND PRFL SHOWING 45KT 2K-3K FT WINDS. AN
AREA OF LIGHT SNOW THAT MOVED THROUGH CNTRL INTO ERN UPPER MI WAS
SUPPORTED BY A BAND OF 285K-290K ISENTROPIC LIFT. OTHERWISE...PCPN
AHEAD OF THE NRN SHRTWV REMAINED WELL TO THE WEST OVER NW MN.
UPSTREAM LOW LEVELS ALSO REMAINED RELATIVELY DRY WITH GENERALLY ONLY
MID/HIGH CLOUDS OVER WI AND SRN MN. THE ONLY EXECPTION WAS NEAR LAKE
MI WHERE SE WINDS PROVIDED ADDITIONAL MOISTURE FOR LOWER CLOUDS.

TODAY...AFTER THE LIGHT SNOW MOVES OUT OF THE ERN CWA...EXPECT
RELATIVELY QUIET CONDITIONS FOR MUCH OF THE DAY. SINCE MODELS LOW
LEVEL MOISTURE FCST HAVE BEEN TOO HIGH...PER UPSTREAM OB
TRENDS...CHANCES FOR ADDITIONAL PCPN WILL BE LOW UNTIL FORCING WITH
THE NRN STREAM SHRTWV NEARS LATER IN THE AFTERNOON.
NEVERTHELESS...THE SSE FLOW OFF OF LAKE MI MAY PROVIDE ENOUGH
MOISTURE FOR SOME PATCHY DZ/-DZ CNTRL AND EAST LATE THIS MORNING
INTO THE AFTERNOON UNTIL THE DEEPER MOISTURE ARRIVES. A BAND OF
800-600 MB FGEN WILL SUPPORT INCREASING CHANCE FOR SNOW INTO THE
WEST LATE

TONIGHT...MODEL DIFFERENCES REMAIN IN HANDLING INTERACTION/PHASING
OF THE SEPARATE STREAMS AND THE ASSOCIATED SFC LOW
DEVELOPMENT/POSITION. THE ECMWF/GFS AND ESPECIALLY THE GEM REMAINED
SLOWER AND MORE AGGRESSIVE IN STRENGTHENING THE LOW COMPARED THE NAM.
USING A GFS/ECMWF COMPROMISE...INCREASING 700-300 MB QVECTOR CONV
WITH THE NEG TILT TROUGH WOULD SUPPORT EXPANDING AND INTENSIFYING
AREA OF SNOW OVER THE EAST HALF OF UPPER MI. ALTHOUGH SLR VALUES ARE
ONLY IN THE 10/1 TO 15/1 RANGE ARE EXPECTED...QPF VALUES APPROACHING
A 0.25 TO 0.35 INCH COULD BRING AT LEAST 3 TO 4 INCHES OF SNOW
OVERNIGHT.

IN ADDITION THE STRONG MOIST CYCLONIC FLOW DRAWING IN MUCH COLDER
AIR ACROSS WRN LAKE SUPERIOR WILL SUPPORT SIGNIFICANT LAKE ENHANCED
SNOW INTO THE WEST...ESPECIALLY INTO THE HIGHER TERRAIN. SNOWFALL
AMOUNTS BY 12Z/TUE COULD ALREADY APPROACH 6 INCHES AS WINDS PRODUCE
AREAS OF BLOWING SNOW.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 536 AM EST MON FEB 18 2013

...HEAVY LAKE ENHANCED SNOW WITH STRONG WINDS/BLOWING SNOW TUESDAY
AND TUESDAY NIGHT AS WRAPPED UP LOW PRESSURE SYSTEM SLOWLY DEPARTS
UPPER LAKES...

CREDIT TO THE GEM-NH WHICH WAS SHOWING THIS TYPE OF WRAPPED UP SYSTEM
MANY DAYS AGO. SERIES OF H5 TROUGHS OVER THE NORTHERN ROCKIES THIS
MORNING FCST TO DIG INTO NORTHERN MN AND WI LATE TONIGHT THROUGH
TUESDAY MORNING. AS STRONG SHORTWAVE ROUNDS BASE OF TROUGH ALONG
WITH 250MB JET STREAKS LIFTING INTO ONTARIO AND LIFTING INTO LOWER
MICHIGAN...EXPECT SFC-H85 LOWS MOVING THROUGH TO DEEPEN. BASED ON
MODEL TRENDS...SEEMS LIKE WE ARE HEADING TOWARD MSLP BY 12Z TUESDAY
A BIT BLO 990MB...PERHAPS DOWN TO MID 980S MB. DUE TO COUPLED JET
STREAKS AND DIVERGENCE ALOFT ALONG WITH DEEPENING TROUGH...EXPECT
SWATH OF MODERATE TO HEAVY SNOW OVER MAINLY EAST CWA. H7 MIXING
RATIOS OVR 2.5G/KG AND QPF BULLSEYE OVR 0.25 INCH SUGGESTS ADDITIONAL
2-4 INCHES OF SNOW IN THE MORNING FROM MUNISING TO NEWBERRY AND MAYBE
AS FAR SOUTH AS MANISTIQUE. MEANWHILE...IN THE WEST AND NCNTRL
CWA...COLD AIR ADVECTION ON MOIST CYCLONIC FLOW LEADS TO PERIOD OF
SIGNIFICANT LAKE ENHANCED SNOW. MOISTURE PRESENT THROUGH AT LEAST
H7...THOUGH LIFT WITHIN THE LARGER SCALE IS LIMITED. SOUNDINGS DO NOT
SHOW TYPICAL OVERWHELMING INSTABILITY WITH HIGHER EQL AND LAKE
INDUCED CAPES AS INVERSION IS GENERALLY LESS THAN 6KFT THROUGH EVENT.
EVEN SO...H85 TEMPS FALLING TO -15C TO -20C BY 18Z TUESDAY WITH THE
SHARP CYCLONIC FLOW IN LOWEST LEVELS WILL OFFSET THIS AND LEAD TO THE
MODERATE TO HEAVY LAKE SNOWS. EXPECT 12HR SNOW AMOUNTS TOPPING OUT
AROUND 6 INCHES...BUT LOCALLY HEAVIER AMOUNTS MAY OCCUR...MAINLY IN
AREAS WITH ADDITIONAL UPSLOPE LIFTING GOING ON.

SNOW NOT ONLY ASPECT OF THE SYSTEM THOUGH...NOT BY A LONG SHOT.
WINDS AND BLOWING SNOW MAY BECOME QUITE SIGNIFICANT WITH THIS SYSTEM
BY TIME WE REACH LATER TUESDAY AND TUESDAY EVENING. DEEPENING LOW
PRESSURE AND BLYR WINDS 40 KTS+ ALONG WITH COLD AIR ADVECTION
RESULTS IN CONSIDERABLE BLOWING SNOW/POOR VSBY. WITHOUT DEEPER
MOISTURE THIS IMPACT WOULD BE LIMITED TO WHERE LAKE EFFECT BANDS
OCCUR. IN THIS SETUP THOUGH...ENVISION MORE WIDESPREAD SNOW WITH
POCKETS OF HEAVIER SNOW AND ENHANCED BLOWING SNOW. GIVEN EXPECTED
NNW BLYR WINDS...FAVORED AREAS WILL BE WESTERN CWA FROM IWD THROUGH
ROCKLAND AND TO TWIN LAKES AND ALSO OVR MOST OF EASTERN SNOWBELTS
FROM AU TRAIN TO NEWBERRY AND FARTHER EAST TOWARD THE SAULT. NORTH
FLOW MAY ALSO RESULT IN SEVERAL INCHES OF SNOW OVR HIGHER TERRAIN OF
KEWEENAW COUNTY AS WELL. WITH WIND AND SNOW...TRAVEL CONDITIONS OVER
MUCH OF UPR MICHIGAN WILL BE QUITE POOR MUCH OF TUESDAY AND TUESDAY
NIGHT.

TRENDS FROM MODELS TOWARD MORE AMPLIFIED SYSTEM /EVEN 00Z ECMWF IS
COMING ALONG TO THIS NOW/ ALONG WITH THE STRONG WIND FIELDS LED
TOWARD ISSUING WINTER STORM WARNINGS/ADVISORIES BEGINNING THIS
EVENING
ALONG ALL OF LK SUPERIOR AND INTO EASTERN CWA. LONG DURATION OF
DIFFICULT TRAVEL CONDITIONS EXPECTED WITH SOME SPOTS IN THE EAST NOT
SEEING IMPROVEMENT TIL LATER WEDNESDAY.

ONE OTHER NOTE...SINCE 925MB WINDS OF 35-40 KTS EXTEND AS FAR INLAND
AS IRON COUNTY TO DELTA AND SOUTHERN SCHOOLCRAFT COUNTIES AND THERE
IS LARGER SCALE MOISTURE...HEAVIEST SNOW AND BLSN IMPACTS MAY AFFECT
LOCATIONS FARTHER INLAND THAN NORMALLY WOULD OCCUR. DUE TO THIS
EXPECTATION PLACED HEADLINES UP FOR DELTA/SOUTHERN SCHOOLCRAFT.

REST OF LONG TERM...MINIMAL CHANGES AS FOCUS WAS CLEARLY ON UPCOMING
SYSTEM. DESPITE INVERSIONS BLO 5KFT LATE WED NIGHT INTO THURSDAY
EXPECT LGT LK EFFECT/FLURRIES WITH NORTH FLOW AND 925MB TEMPS BLO
-13C. NEXT SYSTEM STILL ON TRACK...IN A WEAKENING STATE...FOR FRIDAY
AND FRIDAY NIGHT. CHANCE POPS RETAINED FOR NOW. OTHERWISE...SLIGHT
WARMING TREND REMAINS IN STORE FOR NEXT WEEKEND WITH MAX TEMPS BACK
TO AROUND 30 DEGREES.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 643 AM EST MON FEB 18 2013

THE COMBINATION OF GREATER MOISTURE INFLOW INTO THE REGION ON
INCREASING SOUTHERLY WINDS...BRIEF MOISTENINT WITH A BAND OF LIGHT
SNOW AND UPSLOPE SSE FLOW FROM LAKE MICHIGAN HAS LOWERED BROUGH IFR
CIGS INTO SAW. SO...EXPECT MAINLY IFR WITH POTENTIAL FOR SOME LOWER
END MVFR TO PERSIST THROUGH THE DAY. SNOW IS EXPECTED TO DEVELOP
LATE THIS AFTERNOON AND EVENING WHICH WILL KEEP CONDITIONS IN THE
IFR RANGE.

AT IWD/CMX...CONDITIONS LATER IN THE DAY WILL ALSO FALL TO IFR
FOLLOWING PASSAGE OF A COLD FRONT...A WIND SHIFT TO AN UPSLOPE NW
WIND AND THE ONSET OF -SN. THE COMBINATION OF HEAVIER SNOW AND
INCREASING UPSLOPE NW WINDS ALONG WITH BLSN WILL LIKELY CAUSE LIFR
WX AT CMX/IWD TONIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 536 AM EST MON FEB 18 2013

SOUTH WINDS TO 30 KTS OVER FAR EASTERN SECTION TODAY THEN DEEPENING
LOW PRESSURE OVER UPR LAKES TONIGHT INTO TUESDAY MORNING RESULTS IN
NORTH-NORTHWEST GALES TO 45 KTS WITH POSSIBLE STORM FORCE GUSTS
THROUGH TUESDAY NIGHT. PERIOD OF STRONGEST WINDS FROM LATE TONIGHT
INTO TUESDAY MORNING OVER CNTRL LK SUPERIOR. LOW SLOWLY MOVES AWAY
BUT EXPECT GALES TO 35 KTS INTO WEDNESDAY. HIGH PRESSURE DROPPING IN
FROM CANADA RESULTS IN WINDS DIMINISHING TO LESS THAN 30 KTS
WEDNESDAY NIGHT AND THURSDAY. GALE WARNINGS POSTED WITH THIS SHIFT.
HEAVY FREEZING SPRAY OVER MOST OF THE LAKE THROUGH WEDNESDAY
NIGHT...SO PUT UP THOSE WARNINGS AS WELL. ANOTHER LOW PRESSURE
SYSTEM MOVES ACROSS UPR LAKES ON FRIDAY. EAST WINDS TO 30 KTS
EXPECTED FRIDAY AND FRIDAY NIGHT AS THE SYSTEM MOVES ACROSS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 5 PM EST /4 PM CST/ THIS AFTERNOON TO
MIDNIGHT EST /11 PM CST/ TUESDAY NIGHT FOR MIZ002-009-084.

WINTER STORM WARNING FROM 7 PM THIS EVENING TO 5 PM EST
WEDNESDAY FOR MIZ006-007-014-085.

WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR MIZ001-003.

WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
TUESDAY NIGHT FOR MIZ004-005-013.

LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 AM EST /6 AM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-240>251-263>267.

GALE WARNING FROM 5 AM TUESDAY TO 7 PM EST WEDNESDAY FOR
LSZ245>251-265>267.

GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR
LSZ243-244-264.

GALE WARNING FROM 9 PM EST /8 PM CST/ THIS EVENING TO 5 AM EST
/4 AM CST/ WEDNESDAY FOR LSZ240>242-263.

GALE WARNING UNTIL 1 PM EST /NOON CST/ TUESDAY FOR LSZ162.

LAKE MICHIGAN...
GALE WARNING FROM 7 AM TUESDAY TO 7 AM EST WEDNESDAY FOR LMZ248-
250.

SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

538 AM EST MON FEB 18 2013

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 536 AM EST MON FEB 18 2013

...HEAVY LAKE ENHANCED SNOW WITH STRONG WINDS/BLOWING SNOW TUESDAY
AND TUESDAY NIGHT AS WRAPPED UP LOW PRESSURE SYSTEM SLOWLY DEPARTS
UPPER LAKES...

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 624 PM EST SUN FEB 17 2013

ALTHOUGH THERE WL BE THICKENING MID CLDS TNGT AND EVEN SOME FLURRIES
IN ADVANCE OF LO PRES MOVING E FM THE NRN PLAINS...EXPECT VFR
CONDITIONS THRU 12Z AS STRENGTHENING SLY FLOW INITIALLY TAPS ONLY
VERY DRY LLVL AIR OBSVD UPSTREAM. THIS STRENGTHENING S WIND WL
RESULT IN LLWS AT THE TAF SITES. AS THE S FLOW SLOWLY DRAWS MORE
LLVL MSTR INTO THE UPR LKS...CONDITIONS ARE LIKELY TO DETERIORATE TO
MVFR EARLY MON AND TO IFR AT SAW IN THE AFTN WITH UPSLOPE WIND
COMPONENT ENHANCING THE LLVL MOISTENING. AT IWD/CMX...CONDITIONS
LATER IN THE DAY WL ALSO FALL TO IFR FOLLOWING PASSAGE OF COLD
FNT/WSHFT TO AN UPSLOPE NW WIND/ONSET OF -SN.
&&