Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/01/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1041 PM MST TUE JAN 29 2013
.AVIATION...
LIGHT SNOW SHOWERS IN THE VCNTY OF BOTH KCOS AND KPUB ARE EXPECTED
TO COME TO AN END AROUND 09Z...WITH VFR CONDITIONS THEN EXPECTED
THROUGH WEDNESDAY. WEDNESDAY AFTERNOON SOME BREEZY WEST TO
NORTHWEST WINDS WILL BE POSSIBLE AT BOTH KCOS AND KPUB. EXPECTING
KALS TO HAVE VFR CONDITIONS FOR THE NEXT 24 HOURS...WITH SOME
BREEZY WESTERLY WINDS POSSIBLE WEDNESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 302 PM MST TUE JAN 29 2013/
SHORT TERM...
(TONIGHT AND WEDNESDAY)
SNOW HAS BEEN WINDING DOWN ACROSS THE SOUTHEAST MOUNTAINS/I-25
CORRIDOR AS FOCUS FOR HEAVIER SNOW SHIFTS EASTWARD ACROSS THE PLAINS
AHEAD OF THE MAIN UPPER TROF AXIS. SNOWFALL REPORTS THAT HAVE COME
IN SO FAR HAVE INDICATED 2 TO 5 INCHES ACROSS THE LOWER EASTERN
SLOPES OF THE SE MTS AND ADJACENT I-25 CORRIDOR. GOBBLERS KNOB WEB
CAM IN SOUTHERN PROWERS COUNTY STARTING TO PICK UP SOME HEAVIER SNOW
AS OF 2 PM...WITH GROUND NEARLY SNOW COVERED.
FOCUS FOR HEAVIER SNOW WILL CONTINUE TO SHIFT SOUTH AND EASTWARD
THROUGH THE LATE AFTERNOON AND EARLY EVENING. STILL THINKING
GENERALLY 1-3 INCHES OF SNOWFALL FOR THE SOUTHEAST PLAINS GENERALLY
TO THE SOUTH AND EAST OF KLHX. THE HEAVIEST WILL FALL ALONG THE
NORTHERN SLOPES OF THE RATON MESA AND ACROSS BACA COUNTY. WHILE 18Z
NAM CONTINUES TO DEPICT A BAND OF HEAVIER SNOW AMOUNTS OF 1 TO 3
INCHES ACROSS BACA/LAS ANIMAS...THE RAP HAS BACKED OFF ON THIS AND
NOW PLACES THE BAND WELL TO THE SOUTH OF THE AREA. HRRR ALSO
APPEARS TO HAVE BACKED OFF ON SNOW AMOUNTS ACROSS BACA COUNTY...SO
WILL HOLD OFF ON ISSUING ANY HIGHLIGHTS AT THIS POINT AND STICK WITH
THE GENERALLY 1-3 INCH AMOUNTS. WITH INSTABILITY STILL IN PLACE WITHIN THE
TROF AXIS...THERE STILL COULD BE SOME LINGERING SNOW SHOWERS BEHIND
THE TROF AXIS THROUGH THE EVENING...THUS WILL KEEP SCATTERED POPS IN
AND NEAR THE MOUNTAINS UNTIL 06Z.
MEANWHILE...ALTHOUGH HEAVIER SNOW WILL BE TAPERING
OFF...NORTHWESTERLY OROGRAPHICS AND INCREASING WINDS ALOFT ON THE
BACK SIDE OF THE UPPER TROF WILL KEEP WIDESPREAD LIGHT TO MODERATE
SNOW GOING ALONG THE SAWATCH AND MOSQUITO RANGES THROUGH THE
NIGHT...WITH THE WIND CAUSING SOME AREAS OF BLOWING SNOW. WITH
TEMPERATURES FALLING INTO THE NEGATIVE READINGS OVERNIGHT...MAY ALSO
SEE SOME WIND CHILL ADVISORY READINGS IN THE -25 TO -34 DEGREE
RANGE. PREVIOUS SHIFT ISSUED A LONG DURATION WINTER WEATHER
ADVISORY FOR THIS AREA...AND THIS STILL LOOKS GOOD...THOUGH HIGHEST
IMPACT MAY BE DUE TO MORE BLOWING SNOW INITIALLY. WILL ADD MENTION
OF THE WIND CHILL VALUES TO THE UPDATED WSW. MAY ALSO SEE WIND
CHILL ADVISORY VALUES ACROSS THE HIGHER ELEVATIONS OF THE EASTERN
SAN JUAN AND LA GARITA MOUNTAINS...THOUGH GIVEN THE SPOTTY NATURE
WILL HOLD OFF ON ISSUING A WIND CHILL ADVISORY AT THIS POINT.
TRAILING SHORTWAVE ENERGY DROPPING IN ON WEDNESDAY SHOULD ENHANCE
SNOWFALL AGAIN ACROSS THE CENTRAL MOUNTAINS WEDNESDAY AFTERNOON.
SHOULD SEE 24 HOUR ACCUMULATIONS OF 2 TO 8 INCHES THROUGH WEDNESDAY
AFTERNOON FOR THIS AREA. ELSEWHERE WX WILL BE PRIMARILY DRY. GUSTY
NORTHWEST 20-40 MPH WINDS WILL MIX DOWN INTO THE LOWER ELEVATIONS
AND ADJACENT I-25 CORRIDOR WEDNESDAY AFTERNOON WHERE GUSTS TO AROUND
20-30 MPH WILL BE POSSIBLE. SNOW COVER WOULD BODE FOR KEEPING TEMPERATURES
ON THE COOL SIDE OF GUIDANCE TOMORROW...THOUGH WITH THE WINDS AND
SOME MIXING...THEY SHOULD MANAGE TO WARM ABOVE FREEZING ACROSS MOST
OF THE PLAINS. LEANED MAX TEMPS TOWARDS THE COOLER SIDE OF GUIDANCE
FOR NOW. MOUNTAIN AREAS WILL SEE HIGHS GENERALLY IN THE TEENS
AND 20S...WITH SOME LOWER 30S ACROSS THE VALLEY AREAS. -KT
LONG TERM...
(WEDNESDAY NIGHT THROUGH TUESDAY)
WEDNESDAY NIGHT AND THURSDAY...BRISK NW FLOW ALOFT CONTINUES ACROSS
THE REGION THROUGH THURSDAY...WITH MODELS AGREEING ON KEEPING A NEARLY
CONSTANT THREAT OF LIGHT TO MODERATE PCPN OVER THE CENT MTS THROUGH
THE EVE. THOUGH NEW SNOW AMOUNTS WILL ACCUMULATE TO 12 TO 16
INCHES BY THURSDAY AFTN...ANOTHER REAL CONCERN WILL BE THE STRONG
WINDS ALOFT THAT WILL BE EXPERIENCED ACROSS THE HIGHER TERRAIN. A
100 KT CORE OF THE UPPER JET NOSES INTO THE NW QUAD OF COLORADO
THROUGH WEDNESDAY NIGHT...BEFORE MOVING EAST AND WINDS WEAKEN BY
MIDDAY THURSDAY. THEREFORE...ONGOING WINTER WX ADV FOR THE HIGHER
ELEVATIONS OF LAKE AND CHAFFEE COUNTIES LOOKS GOOD. MAX TEMPS ON
THURSDAY ARE EXPECTED TO REBOUND INTO THE 50S FOR THE PLAINS...30S
AND 40S FOR THE HIGH VALLEYS.
FRIDAY AND SATURDAY...TEMPORARY RIDGING ACROSS THE DESERT SW AND
COLORADO TO START THE WEEKEND...WITH DRY AND MILD CONDITIONS
EXPECTED. MODELS DO INDICATE A MINOR UPPER DISTURBANCE ROLLING
ACROSS THE ROCKY MT REGION...BUT CONTINUE TO KEEP THIS FEATURE JUST
NORTH OF THE CWA AND FEEL THAT THE ONLY EFFECT WILL BE AN INCREASE
IN HIGH LEVEL CLOUDINESS. WINDS REMAIN SOMEWHAT LIGHT...SO NO
APPRECIABLE CHANGE IN THE TEMPS IS EXPECTED.
SUNDAY THROUGH TUESDAY...AN UPPER LOW PRES SYSTEM JUST OFF THE S CA
COAST WILL START PUSHING A PLUME OF WARMER PACIFIC MOISTURE UP
ACROSS AZ AND THE 4 CORNERS STARTING ON SUNDAY. AT THE SAME TIME...AN
UPPER DISTURBANCE DROPPING DOWN ACROSS MT AND WY WILL ACT UPON THIS
MOISTURE TAP AND SQUEEZE OUT SOME ISOLATED SHOWERS ALONG THE CONTDVD
LATE SUNDAY. AS THIS FEATURE MOVES EAST AND OUT OF THE
AREA MONDAY...PCPN CHANCE DIMINISH. HOWEVER...LATE MONDAY THE LOW
OFF THE WEST COAST STARTS TO FILL AND MOVE ONSHORE...BRINGING A
SHOT FOR PCPN ONCE AGAIN TO THE CONTDVD STARTING TUESDAY MORNING.
27
AVIATION...
VFR CIGS ACROSS THE TAF SITES WILL GRADUALLY DIMINISH THROUGH THE
EVENING. THERE COULD BE A LIGHT SNOW SHOWER IN THE VICINITY OF KCOS
THIS EVENING...THOUGH CHANCE LOOKS TOO REMOTE TO WARRANT INCLUSION
IN THE TAF AT THIS POINT. WINDS WILL DECREASE TO UNDER 6 KTS AT KPUB
AND KALS OVERNIGHT...THOUGH KCOS MAY CONTINUE TO SEE SOME ENHANCED
NORTH WINDS IN THE 5-10 KT RANGE THROUGH THE NIGHT.
MEANWHILE...IFR TO LIFR CIGS AND VIS IN -SHSN WILL CONTINUE ALONG
THE CONTDVD...PARTICULARLY ACROSS THE CENTRAL MTS...RESULTING IN
WIDESPREAD MTN OBSCURATIONS. MVFR TO BRIEFLY IFR CIGS WILL CONTINUE
ACROSS THE SOUTHEAST PLAINS THROUGH EARLY EVENING BEFORE THE SNOW
BAND PUSHES SOUTHEAST OF THE AREA OVERNIGHT.
ON WEDNESDAY...VFR CIGS/VIS EXPECTED FOR THE TAF SITES...WITH SOME
BREEZY WEST TO NW WINDS 10-15 KTS POSSIBLE AT KCOS AND KPUB DURING
THE AFTERNOON. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THURSDAY FOR COZ058-060.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
929 PM EST THU JAN 31 2013
.SYNOPSIS...
A CANADIAN AIR MASS MOVES INTO THE REGION...
TEMPERATURES WILL BE MUCH COLDER TONIGHT WITH A DIMINISHING WIND.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO AFFECT THE WESTERN
ADIRONDACKS AND MOHAWK VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT
SOUTH AND WEST OF THE REGION TOMORROW...WITH COLD TEMPERATURES AND
BREEZY CONDITIONS. SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO
BE IN PLACE OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 915 PM...MAIN LAKE EFFECT BAND NOW BECOMING MORE
DISORGANIZED AND SHIFTING SOUTHWARD THROUGH HERKIMER AND HAMILTON
COUNTIES WITH SNOWFALL AMOUNTS GENERALLY IN THE 4-6 RANGE REPORTED
BY LOCAL SPOTTERS. ELSEWHERE...A BAND OF SNOW SHOWERS...AIDED BY
MOHAWK VALLEY CONVERGENCE AND LAKE-ENHANCED MOISTURE HAD REACHED
THE CAPITAL DISTRICT. THIS BAND WILL CONTINUE TO IMPACT THE
CAPITAL REGION THROUGH THE NEXT COUPLE OF HOURS...WITH GENERALLY A
DUSTING TO A FEW TENTHS OF ACCUMULATION.
WINDS ARE STARTING TO DIMINISH SLIGHTLY AS THE PRESSURE GRADIENT
BEGINS TO RELAX. WINDS WILL STILL REMAIN 10-15KTS SUSTAINED WITH
SOME GUSTS OVER 25KTS POSSIBLE UNTIL 3Z. CURRENT FORECAST LOOKS TO
BE SPOT ON. ONLY MINOR CHANGES TO CURRENT TEMPS, DEWPOINTS AND
WIND.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE
WESTERN ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE
NAM12 AND 3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD
DURING THE OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT
MULTI-LAKE CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES
AND STRONG LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD
SUGGEST THAT THIS BAND REACHES WELL INTO OUR AREA. AS A
RESULT...HAVE ALSO INCLUDED A LAKE EFFECT SNOW ADVISORY FOR
HAMILTON COUNTY...IN ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN
HERKIMER. SNOW TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND
3-6 INCHES ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
WINDS WILL BE OUT OF THE WEST TO NORTHWEST 12-20 KTS. WIND GUST
OF 20 TO 25 KT OUT OF THE WEST TO NORTHWEST WILL BE POSSIBLE. CIGS
AND VIS WILL GENERALLY BE VFR OVERNIGHT WITH POSSIBLE MVFR IN SHSN.
HAVE INCLUDED VICINITY SHOWERS ACROSS ALL TAF ROUTES TONIGHT AND
EARLY TOMORROW.
WEST TO NORTHWEST WINDS SHOULD BECOME GUSTY AGAIN TOMORROW AFTER
ABOUT 16Z. CEILINGS AND VISIBILITIES WILL BE VFR.
OUTLOOK... FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
FOR SPECIFIC RIVER AND LAKE FORECASTS...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/VTK/IRL
NEAR TERM...FRUGIS/VTK
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...VTK/IRL
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
802 PM EST THU JAN 31 2013
.SYNOPSIS...
A CANADIAN AIR MASS MOVES INTO THE REGION...
TEMPERATURES WILL BE MUCH COLDER TONIGHT WITH A DIMINISHING WIND.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO AFFECT THE WESTERN
ADIRONDACKS AND MOHAWK VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT
SOUTH AND WEST OF THE REGION TOMORROW...WITH COLD TEMPERATURES AND
BREEZY CONDITIONS. SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO
BE IN PLACE OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LATEST RADAR PICTURE AS OF 800 PM SHOWING SNOW BAND ACROSS
ADIRONDACKS BECOMING MORE DISORGANIZED AND SHIFTING SOUTHWARD.
THERE IS SHSN MORE ACTIVITY ACROSS THE MOHAWK VALLEY AND CAPITAL
DISTRICT. WILL UPDATE FORECAST TO INCREASE POPS AND COATING OF
SNOW.
WINDS ARE STARTING TO DIMINISH SLIGHTLY AS THE PRESSURE GRADIENT
BEGINS TO RELAX. WINDS WILL STILL REMAIN 10-15KTS SUSTAINED WITH
SOME GUSTS OVER 25KTS POSSIBLE UNTIL 3Z. CURRENT FORECAST LOOKS TO
BE SPOT ON. ONLY MINOR CHANGES TO CURRENT TEMPS, DEWPOINTS AND
WIND.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE
WESTERN ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE
NAM12 AND 3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD
DURING THE OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT
MULTI-LAKE CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES
AND STRONG LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD
SUGGEST THAT THIS BAND REACHES WELL INTO OUR AREA. AS A
RESULT...HAVE ALSO INCLUDED A LAKE EFFECT SNOW ADVISORY FOR
HAMILTON COUNTY...IN ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN
HERKIMER. SNOW TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND
3-6 INCHES ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
WINDS WILL BE OUT OF THE WEST TO NORTHWEST 12-20 KTS. WIND GUST
OF 20 TO 25 KT OUT OF THE WEST TO NORTHWEST WILL BE POSSIBLE. CIGS
AND VIS WILL GENERALLY BE VFR OVERNIGHT WITH POSSIBLE MVFR IN SHSN.
HAVE INCLUDED VICINITY SHOWERS ACROSS ALL TAF ROUTES TONIGHT AND
EARLY TOMORROW.
WEST TO NORTHWEST WINDS SHOULD BECOME GUSTY AGAIN TOMORROW AFTER
ABOUT 16Z. CEILINGS AND VISIBILITIES WILL BE VFR.
OUTLOOK... FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
FOR SPECIFIC RIVER AND LAKE FORECASTS...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/VTK
NEAR TERM...FRUGIS/VTK
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...VTK
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
655 PM EST THU JAN 31 2013
.SYNOPSIS...
S A CANADIAN AIR MASS MOVES INTO THE REGION...
TEMPERATURES WILL BE MUCH COLDER TONIGHT WITH A DIMINISHING WIND.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO AFFECT THE WESTERN
ADIRONDACKS AND MOHAWK VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT
SOUTH AND WEST OF THE REGION TOMORROW...WITH COLD TEMPERATURES AND
BREEZY CONDITIONS. SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO
BE IN PLACE OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 630 PM EST...WINDS ARE STARTING TO DIMINISH SLIGHTLY AS THE
PRESSURE GRADIENT BEGINS TO RELAX. WINDS WILL STILL REMAIN
10-15KTS SUSTAINED WITH SOME GUSTS OVER 25KTS POSSIBLE UNTIL 3Z.
CURRENT FORECAST LOOKS TO BE SPOT ON. ONLY MINOR CHANGES TO CURRENT
TEMPS, DEWPOINTS AND WIND.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE
WESTERN ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE
NAM12 AND 3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD
DURING THE OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT
MULTI-LAKE CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES
AND STRONG LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD
SUGGEST THAT THIS BAND REACHES WELL INTO OUR AREA. AS A
RESULT...HAVE ALSO INCLUDED A LAKE EFFECT SNOW ADVISORY FOR
HAMILTON COUNTY...IN ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN
HERKIMER. SNOW TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND
3-6 INCHES ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
WINDS WILL BE OUT OF THE WEST TO NORTHWEST 12-20 KTS. WIND GUST
OF 20 TO 25 KT OUT OF THE WEST TO NORTHWEST WILL BE POSSIBLE. CIGS
AND VIS WILL GENERALLY BE VFR OVERNIGHT. HAVE INCLUDED VICINITY
SHOWERS ACROSS ALL TAF ROUTES TONIGHT AND EARLY TOMORROW.
WEST TO NORTHWEST WINDS SHOULD BECOME GUSTY AGAIN TOMORROW AFTER
ABOUT 16Z. CEILINGS AND VISIBILITIES WILL BE VFR.
OUTLOOK... FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
FOR SPECIFIC RIVER AND LAKE FORECASTS...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/VTK
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...VTK
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1005 AM EST WED JAN 30 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH NORTH OF THE REGION THIS MORNING...BRINGING
MILDER CONDITIONS. WINDS WILL BECOME VERY WINDY LATE THIS
AFTERNOON AND TONIGHT AHEAD OF A STRONG COLD FRONT. HEAVY SHOWERS
AND ISOLATED THUNDERSTORMS ARE POSSIBLE. THE FRONT WILL PUSH
ACROSS THE REGION THURSDAY MORNING...BRINGING WITH MORE WINDY
CONDITIONS AND COLDER TEMPERATURES. A COUPLE OF RELATIVELY FAST
MOVING SYSTEMS MAY PRODUCE LIGHT SNOW ON SUNDAY AND AGAIN ON
TUESDAY OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1005 AM UPDATE...
DENSE FOG CONTINUES TO AFFECT INTERIOR SOUTHERN NEW ENGLAND AS OF
MID TO LATE MORNING. BASED ON CURRENT OBSERVATIONS AND TRENDS WILL
LIKELY HAVE TO EXTEND IT INTO THE AFTERNOON WITH UNSEASONABLY HIGH
DEWPOINT OVER RUNNING TEMPS IN THE LOWER TO MIDDLE
30S. MEANWHILE...ACROSS THE COASTAL PLAIN THE SURFACE HAS MIXED OUT
AND TEMPS HAVE SOARED INTO THE 50S. IN FACT...A FEW LOCATIONS
MAY TAKE A RUN AT 60 LATER THIS AFTERNOON. NOW WE ARE CONFIDENT THAT
TEMPERATURES WILL EVENTUALLY REACH INTO THE 50S ACROSS THE
INTERIOR...BUT ITS UNCERTAIN EXACTLY HOW FAST THAT WILL OCCUR. IN
SOME LOCATIONS...PARTICULARLY ACROSS SOUTHERN NH THIS MAY NOT HAPPEN
UNTIL EARLY EVENING. WE FOLLOWED THE HRRR MODEL TEMPS WHICH SEEM TO
HAVE A GOOD HANDLE ON THE SITUATION.
MAINLY DRY WEATHER EXPECTED FOR THE NEXT FEW HOURS...BUT SOME
SCATTERED SHOWERS MAY WORK INTO THE INTERIOR LATER IN THE AFTERNOON
BUT CERTAINLY NOT EXPECTING A WASHOUT. BEST DYNAMICS WILL REMAIN
WELL TO OUR WEST FOR THE REMAINDER OF THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
TONIGHT...
SHOWERS WILL MOVE IN AHEAD OF APPROACHING FRONT...SOME OF WHICH
MAY PRODUCE HEAVY DOWNPOURS. GOOD INSTABILITY CONTINUES AS K
INDICES RISE TO THE MID 30S...SO HAVE MENTIONED ISOLD
THUNDERSTORMS THROUGH MOST OF THE NIGHT. BIGGEST EFFECTS WILL BE
DUE TO STRONG WINDS WITH TIGHT PRES GRADIENT. H85 AND H925 JETS ON
ORDER OF 70-80 KT WILL CROSS THE REGION AND...WITH MILD TEMPS
REMAINING...EXPECT SOME VERY STRONG GUSTS TO MIX DOWN ESPECIALLY
WITH ANY CONVECTION THAT DEVELOPS. LOOKS LIKE THE BIGGEST THREAT
FOR THE STRONGEST GUSTS WILL BE ACROSS SOUTHEASTERN SECTIONS.
WITH THE THREAT OF DAMAGING WINDS ACROSS RI/SE MA...HAVE ISSUED
HIGH WIND WARNING FOR THOSE AREAS. WOULD NOT BE SURPRISED TO SEE
GUSTS ON ORDER OF 50-55 MPH...MAYBE EVEN HIGHER. ELSEWHERE...HAVE
KEPT THE HIGH WIND WATCH IN PLACE...THOUGH COULD BE CONVERTING TO
EITHER A WIND ADVISORY OR WARNING DURING THE DAY SHIFT.
EXPECT TEMPS TO ACTUALLY TOP OFF LATE TONIGHT OR EVEN INTO THE WEE
HOURS OF THURSDAY. A FEW SPOTS MAY ACTUALLY SEE 60 DEGREES...
LIKELY ACROSS EASTERN AREAS.
SHORT RANGE MODELS IN GOOD AGREEMENT THAT THE COLD FRONT WILL
MOVE INTO WESTERN AREAS AFTER 06Z...REACHING THE E COAST AROUND
12Z OR SO. COLDER AIR WILL START TO SPILL INTO WESTERN AREAS BY
AROUND SUNRISE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* WIND ADVISORY STRENGTH WINDS POSSIBLE BEHIND FRONT THU
* COLDER THU NIGHT INTO THE WEEKEND
* CHANCE OF SNOW...PROBABLY LIGHT...ON SUN AND AGAIN TUE
OVERALL PICTURE...STRONG COLD FRONT MOVES OFFSHORE THU. BROAD
UPPER LONG WAVE TROF DOMINATES ACROSS EASTERN N AMERICA IN THE
LONGER TERM PERIOD WITH SERIES OF QUICK MOVING SHORT WAVE TROFS
PASSING THROUGH. SURFACE REFLECTION OF THESE SHORTWAVES ARE
CLIPPER SYSTEMS. LOOKS LIKE ONE PASS THRU ON SUN AND ANOTHER TUE.
SOME UNCERTAINTY WHETHER THE SURFACE CENTERS WILL PASS JUST N OR
JUST S OF SOUTHERN NEW ENGLAND. STEADIER AND SOMEWHAT HIGHER QPF
EXPECTED NORTH OF THE CENTER...AND SURFACE LOWS PASSING S OF
SOUTHERN NEW ENGLAND CAN ADD A LITTLE MORE QPF DUE TO SOME ATLC
INFLOW. AT THIS TIME...NONE OF THESE SYSTEMS LOOK ESPECIALLY
POTENT WITH ANY SNOW ACCUM LOOKING TO BE UNDER ADVISORY
THRESHOLDS. THIS PICTURE COULD CHANGE AS WE GET CLOSER TO THESE
EVENTS.
DAY BY DAY PICTURE...
THU...DEEP MIXING BEHIND COLD FRONT MAY BE ENOUGH TO SUPPORT WIND
ADVISORIES OVER PORTIONS OF THE AREA DURING THE LATE MORNING AND
AFTERNOON. NO HEADLINES NOW DUE TO THE PREFRONTAL HIGH WIND
WARNINGS/WATCHES. TEMPS MAY HOLD STEADY FOR A WHILE DURING THE
MORNING AND START A STEADY SLIDE DURING THE AFTERNOON INTO THU
NIGHT DUE TO STRONG COLD AIR ADVECTION.
FRI...ALL MODELS INDICATE A FAIRLY WELL DEFINED SHORT WAVE TROF
PASSAGE ON FRI. MOISTURE IS LIMITED BUT SHARPNESS OF THE TROF
SUGGESTS MENTION OF SCT FLURRIES.
SAT...LOOKS DRY WITH BELOW NORMAL TEMPS.
SUN...SHORT WAVE TROF WITH BAGGINESS IN SFC PRES FIELD DEPICTED BY
MEDIUM RANGE MODELS SUGGESTS A CHANCE OF LIGHT SNOW. ALTHOUGH THE
GFS SHOWS A TAD MORE QPF...THE ECMWF ACTUALLY SHOWS A SOMEWHAT
SHARPER SHORT WAVE TROF WITH A NEGATIVE TILT HINT. PUT POPS AT 50
PERCENT FOR MOST OF AREA FOR SUN.
MON-TUE...MON LOOKS DRY BEFORE ANOTHER SHORT WAVE UPPER TROF AND
SFC CLIPPER LOW PASSES THRU WITH ANOTHER CHANCE OF A PERIOD OF
LIGHT SNOW. GFS ENSEMBLES SEEM TO FAVOR A SLIGHTLY MORE SOUTHERLY
TRACK WITH THIS LOW CENTER COMPARED WITH THE ONE ON SUN BUT TOO
FAR OUT FOR MUCH CONFIDENCE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE TO HIGH CONFIDENCE ON TRENDS BUT LOW CONFIDENCE
ON TIMING.
REST OF TODAY...IFR TO LOW END MVFR CONDITIONS WILL PERSIST ON THE COASTAL
PLAIN. MAINLY LIFR CONDITIONS WILL CONTINUE AT LEAST INTO MID
AFTERNOON ACROSS THE INTERIOR AS A RESULT OF DENSE FOG. CONDITIONS
SHOULD EVENTUALLY IMPROVE TO IFR...BUT THAT MAY NOT OCCUR UNTIL
LATER THIS AFTERNOON/EARLY EVENING.
LOW LEVEL JET MOVES IN WITH S-SW WINDS UP TO 50-60 KT DURING THIS
AFTERNOON. EXPECT GUSTS UP TO 30-40 KT AT THE SURFACE MAINLY
ACROSS RI/SE MA AND HIGHER TERRAIN.
TONIGHT...MVFR VSBYS/IFR-LIFR CIGS PREVALENT AS STRONG COLD FRONT
MOVES THROUGH. LLWS CONTINUES...APPROACHING 75 KT AT 2KFT ALONG
THE S COAST...CAPE COD AND THE ISLANDS...POSSIBLY APPROACHING 80
KT ACROSS OUTER CAPE COD AND NANTUCKET AFTER 09Z THU. EXPECT
SURFACE GUSTS OF 40-50 KT ACROSS MOST AREAS...POSSIBLY UP TO 55 KT
ALONG S COAST. ISOLD TSTMS POSSIBLE ALONG/AHEAD OF COLD FRONT.
CIGS/VSBYS MAY START TO IMPROVE TO VFR ACROSS CT VALLEY AFTER
09Z...THOUGH LOWER CONFIDENCE ON TIMING.
KBOS TAF...MODERATE CONFIDENCE. IFR TO LOW END MVFR CONTINUES
THROUGH THE AFTERNOON. SW LLWS EXPECTED THIS AFTERNOON/TONIGHT. SW
SURFACE WIND GUSTS UP TO 40-50 KT FROM 03Z-11Z.
KBDL TAF...MODERATE CONFIDENCE. LIFR CONDITIONS IN DENSE FOG SHOULD
EVENTUALLY IMPROVE TO IFR SOMETIME THIS AFTERNOON. S-SW LLWS
EXPECTED THROUGH TONIGHT. S-SW WIND GUSTS UP TO 40-50 KT FROM
04Z-10Z.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE OF VFR CONDITIONS BY LATE MORNING THU AND LASTING
THRU SAT. LOW TO MODERATE CONFIDENCE OF MVFR CIGS/VSBYS WITH
POCKETS OF IFR IN SNOW SUN.
SFC WIND GUSTS 35 TO 45 KT LIKELY BEHIND COLD FRONT THU AFTERNOON
AND CONTINUING TO GUST TO AROUND 25 KT THU NIGHT AND FRI.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE THROUGH TONIGHT.
TODAY...S-SW WINDS WILL PICK UP DURING THE DAY...POSSIBLY REACHING
GALE FORCE ON THE OPEN WATERS THIS AFTERNOON. SEAS WILL ALSO
BUILD...UP TO 8 FT ON THE SOUTHERN WATERS BY EVENING.
TONIGHT...EXPECT STRONGEST S-SW WINDS TO MOVE ACROSS THE WATERS
DURING THIS TIMEFRAME. MAY SEE WIND GUSTS UP TO 50-55 KT OVER THE
OPEN WATERS SO HAVE ISSUED STORM WARNINGS. WINDS MAY NOT QUITE
REACH STORM FORCE ON BOSTON HARBOR OR NARRAGANSETT BAY...SO ISSUED
GALES FOR THOSE WATERS. SEAS MAY REACH 15-18 FT ON THE SOUTHERN
OUTER WATERS LATE TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE TO HIGH CONFIDENCE THRU SATURDAY. MODERATE CONFIDENCE FOR
SUNDAY. STORM FORCE WINDS AHEAD OF FRONT AND THEN STRONG GALE
LIKELY BEHIND THE FRONT FROM W TO NW WITH GUSTS 40 TO 45 KT THU
AFTERNOON AND EVENING. WINDS GRADUALLY DIMINISHING LATE THU NIGHT
INTO FRI BUT MAY STILL SEE GUSTS BETWEEN 25 AND 30 KT ON FRI.
WINDS SHOULD BE UNDER SMALL CRAFT ADVISORY THRESHOLDS ON SAT BUT
POSSIBLY REACHING TO NEAR GALE FORCE IN GUSTS OVER OUTER S AND SE
COASTAL WATERS SUN AFTERNOON FROM W OR WNW AS DEPARTING LOW OVER
THE GULF OF MAINE INTENSIFIES.
AREAS OF FREEZING SPRAY POSSIBLE LATE THU NIGHT THRU SAT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR CTZ002>004.
HIGH WIND WATCH FROM 6 PM EST THIS EVENING THROUGH THURSDAY
MORNING FOR CTZ002>004.
MA...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR MAZ002>005-008>012-
026.
HIGH WIND WATCH FROM 6 PM EST THIS EVENING THROUGH THURSDAY
MORNING FOR MAZ002>016-026.
HIGH WIND WARNING FROM 9 PM THIS EVENING TO 8 AM EST THURSDAY
FOR MAZ017>024.
NH...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR NHZ011-012-015.
HIGH WIND WATCH FROM 6 PM EST THIS EVENING THROUGH THURSDAY
MORNING FOR NHZ011-012-015.
RI...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR RIZ001.
HIGH WIND WARNING FROM 9 PM THIS EVENING TO 8 AM EST THURSDAY
FOR RIZ001>008.
MARINE...STORM WARNING FROM 6 PM THIS EVENING TO 11 AM EST THURSDAY FOR
ANZ231>235-237-250-251-254>256.
GALE WARNING FROM 6 PM THIS EVENING TO 11 AM EST THURSDAY FOR
ANZ230-236.
&&
$$
SYNOPSIS...EVT/THOMPSON
NEAR TERM...FRANK
SHORT TERM...EVT
LONG TERM...THOMPSON
AVIATION...FRANK/EVT/THOMPSON
MARINE...EVT/THOMPSON
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
1132 AM EST WED JAN 30 2013
...WINDY WITH RECORD WARMTH THIS AFTERNOON...
...SLIGHT RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS IN
SOUTHEAST GEORGIA THIS EVENING...
.CURRENTLY...
MORNING SURFACE ANALYSIS DEPICTS A STRONG COLD FRONT EXTENDING
FROM THE OHIO VALLEY SOUTHWARD TO THE CENTRAL GULF COAST AND THE
WESTERN GULF OF MEXICO. WAVES OF LOW PRESSURE ARE PROGRESSING
NORTHEASTWARD ALONG THIS FRONT...AND AN EXTENSIVE SQUALL LINE IS
FOUND JUST AHEAD OF THE FRONT. THIS SQUALL LINE IS ENTERING
NORTHWEST GEORGIA AND TRAILS SOUTH-SOUTHWESTWARD THROUGH ALABAMA
AND SOUTHERN MISSISSIPPI. THIS SQUALL LINE HAS PRODUCED NUMEROUS
REPORTS OF DAMAGING WINDS AND ISOLATED TORNADOES DURING THE PAST
24 HOURS. ALOFT...DEEP-LAYERED RIDGING WAS SITUATED OVER THE
WESTERN ATLANTIC...WHILE A SHARP TROUGH OVER THE MISSOURI VALLEY
WAS IN THE PROCESS OF BECOMING NEGATIVELY TILTED. THIS WEATHER
PATTERN HAS BROUGHT A STRONG VEERING WIND PROFILE INTO OUR REGION.
THE MORNING SOUNDING AT JACKSONVILLE REVEALED 35 KNOT WINDS AT
1000 FEET. SUSTAINED SOUTHERLY SURFACE WIND SPEEDS ARE ALREADY
EXCEEDING 20 KNOTS IN SOME LOCATIONS...AND WE MAY NEED TO EXTEND
THE WIND ADVISORY TO COVER ALL OF OUR COUNTIES THIS AFTERNOON AS
THE GRADIENT TIGHTENS FURTHER. NEAR ALL-TIME JANUARY RECORDS ARE
POSSIBLE THIS AFTERNOON AT JACKSONVILLE (84 DEGREES...LAST REACHED
IN 1982) AND ALMA (83 DEGREES...REACHED YESTERDAY).
THE STORM PREDICTION CENTER HAS MAINTAINED A SLIGHT RISK FOR
SEVERE THUNDERSTORMS DUE TO DAMAGING WIND GUSTS FOR OUR SOUTHEAST
GA COUNTIES. LATEST RUC GUIDANCE SUGGESTS THAT A FEW SHOWERS WILL
DEVELOP OVER THE NORTHEAST GULF THIS AFTERNOON...WHICH WILL MOVE
QUICKLY INTO INTERIOR SE GA. SLOWED THE SOUTHEASTWARD PROGRESSION
OF POPS LATE THIS AFTERNOON/EVENING DUE TO LATEST TRENDS IN THE
SHORT TERM GUIDANCE. MODEL SOUNDINGS SUGGEST A UNI-DIRECTIONAL
SHEAR VECTOR BY THE TIME THE SQUALL LINE ARRIVES IN SE GA AND THE
FL BIG BEND AROUND SUNSET. INSTABILITY WILL ALMOST NEGLIGIBLE PER
MODEL SOUNDINGS...AND THUS NOT EXPECTING A WIDESPREAD SEVERE
WEATHER EVENT...AS DYNAMICS WILL ALSO BE LIFTING NORTHWARD AND
AWAY FROM OUR REGION AS THE SQUALL LINE MOVES THROUGH. RAINFALL
AMOUNTS OF ONE QUARTER TO ONE HALF INCH ARE EXPECTED WITH THIS
EVENT. RAIN SHOULD END OVER OUR SOUTHERN COUNTIES BY 09Z.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST 02Z. SOUTHERLY
SURFACE WINDS WILL REMAIN SUSTAINED AT 15 TO 25 KTS AT ALL TAF
SITES THROUGH 00Z. SURFACE GUSTS UP TO 35 KNOTS ARE EXPECTED AFTER
16Z. SURFACE WINDS WILL BECOME SOUTHWESTERLY TOWARDS 00Z AND THEN
WESTERLY AFTER 06Z FOLLOWING THE PASSAGE OF A COLD FRONT. SHOWERS
AND ISOLATED EMBEDDED THUNDERSTORMS WILL PROGRESS ACROSS THE
TERMINALS FROM 02Z-06Z...WITH A PERIOD OF SUB-VFR CONDITIONS
LIKELY DURING THIS TIME PERIOD. A FEW LINGERING SHOWERS ARE
POSSIBLE THROUGH 09Z. SOUTH TO SOUTHWEST WINDS OF 25 TO 35 KTS
FROM 2000 TO 10000 FEET WILL INCREASE TO 40 TO 55 KTS TOWARDS 00Z.
&&
.MARINE...
SMALL CRAFT ADVISORIES ARE POSTED THROUGH THURSDAY...WITH SOUTH
WINDS INCREASING TO 20 TO 30 KNOTS WITH OCCASIONAL GUSTS TO GALE
FORCE. MORE GALE FORCE GUSTS POSSIBLE TONIGHT AS SQUALL LINE
MOVES OFFSHORE...THEN SHIFT TO W/NW LATE TONIGHT WITH STRONG COLD
AIR PUSH BEHIND THE FRONT THURSDAY MORNING WITH A SUBSIDING TREND
FOR THU AFTERNOON. EXPECTING GALE FORCE GUSTS TO BE PREVALENT
FOR A SHORT TIME DURING THE PASSAGE OF THE SQUALL LINE...SO WE
WILL NOT ISSUE A GALE WARNING AT THIS TIME. HIGH PRESSURE WILL
THEN BUILD IN THROUGH THE WEEKEND...WITH HEADLINES NOT ANTICIPATED
AT THIS TIME.
RIP CURRENTS: LOW RISK WITH SIDE-SHORE FLOW TODAY AND OFFSHORE FLOW
ON THURSDAY.
.FIRE WX...
STRONG SOUTH WINDS TODAY WILL PUSH DISPERSION INDICES WELL ABOVE
CRITICAL LEVELS CLOSE TO 100...BUT RH LEVELS WILL REMAIN GENERALLY
ABOVE 40 PERCENT. FOR THURS...COOL AND DRY AIRMASS WILL PUSH IN ON
NORTHWEST WINDS AND EXPECT CRITICAL RH VALUES DOWN AROUND 25
PERCENT...BUT SUSTAINED WINDS MAY REMAIN JUST BELOW 15 MPH. ERC
VALUES MAY ALSO DECREASE DEPENDING UPON AMOUNT OF RAINFALL
TONIGHT. WILL CONSIDER A FIRE WEATHER WATCH DURING THE AFTERNOON
FORECAST PACKAGE GIVEN THESE FACTORS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 81 45 59 33 / 50 60 10 0
SSI 79 48 59 39 / 20 60 10 0
JAX 84 48 61 33 / 20 70 10 0
SGJ 82 53 61 39 / 20 60 10 0
GNV 82 51 62 33 / 20 70 10 0
OCF 84 53 63 34 / 20 60 10 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR ALACHUA-BAKER-
BRADFORD-COLUMBIA-GILCHRIST-HAMILTON-SUWANNEE-UNION.
LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR CLAY-DUVAL-
FLAGLER-MARION-NASSAU-PUTNAM-ST JOHNS.
GA...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR APPLING-ATKINSON-
BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-ECHOLS-JEFF DAVIS-
PIERCE-WARE-WAYNE.
LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR COASTAL
CAMDEN-COASTAL GLYNN-INLAND CAMDEN-INLAND GLYNN.
AM...SMALL CRAFT ADVISORY UNTIL 3 PM EST THURSDAY FOR ALTAMAHA SOUND
GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-
FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM EST THURSDAY FOR
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-
FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE
TO FLAGLER BEACH FL OUT 20 NM.
&&
$$
NELSON/ENYEDI/CHASE
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
108 PM EST WED JAN 30 2013
.PREV DISCUSSION... /ISSUED 1043 AM EST WED JAN 30 2013/
UPDATE...
HAVE MADE UPDATES TO THE WEATHER AND POP GRIDS...AND SLOWED DOWN
THE CURRENT TIMING OF THE SQUALL LINE. WE ARE STARTING TO SEE
ISOLATED SUPERCELLS OUT FRONT OF THE MAIN LINE. THERE IS AN
ESPECIALLY STRONG TO SEVERE CELL IN EAST CENTRAL ALABAMA. WE ARE
STILL ON TRACK FOR SEVERE THUNDERSTORMS TODAY THROUGH THE AREA.
THE MAIN LINE IS EXPECTED TO PUSH THROUGH THE STATE WITH STRONG
WINDS BEING THE MAIN THREAT. THERE IS ALSO A RISK OF TORNADOES
WITH THESE STORMS...ESPECIALLY ANY SUPERCELLS OUT IN FRONT OF THE
LINE. DID ADJUST THE TEMPERATURES DOWN A FEW DEGREES AS THEY WERE
FORECAST WARMER THAN WHAT WAS GOING ON.
NO OTHER UPDATES ARE EXPECTED AT THIS TIME.
ARG
PREV DISCUSSION... /ISSUED 647 AM EST WED JAN 30 2013/
PREV DISCUSSION... /ISSUED 621 AM EST WED JAN 30 2013/
UPDATE...
SECOND UPDATE TO INCLUDE EXPANDED TORNADO WATCH 17 AREA IN THE
FFC WATCHES/WARNINGS/ADVISORIES SECTION BELOW.
BELANGER
PREV DISCUSSION... /ISSUED 410 AM EST WED JAN 30 2013/
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER VALUES...
1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN PREV SVR
EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
.AVIATION...
18Z UPDATE...
MVFR CONDITIONS EXPECTED THROUGH THE DAY TODAY AND THROUGH EARLY
EVENING ACROSS MOST OF THE AREA. AFTER THE MOISTURE CLEARS
OUT...EXPECT VFR CONDITIONS. MAIN CONCERN TODAY IS THE TIMING OF
THE SQUALL LINE MOVING THROUGH THE AREA. HAVE ADJUSTED THE TAFS
FOR BEST TIMING...POTENTIAL EXISTS FOR SEVERE WEATHER WITH THESE
STORMS INCLUDING DAMAGING WIND AND POSSIBLE TORNADOES.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TIMING...HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
ARG
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
TORNADO WATCH UNTIL 4 PM EST THIS AFTERNOON FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...DADE...
DAWSON...DEKALB...DOOLY...DOUGLAS...FANNIN...FAYETTE...FLOYD...
FORSYTH...GILMER...GORDON...GREENE...GWINNETT...HALL...HANCOCK...
HARALSON...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JONES...LAMAR...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...MORGAN...MURRAY...MUSCOGEE...NEWTON...
NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TOWNS...TROUP...TWIGGS...UNION...UPSON...
WALKER...WALTON...WEBSTER...WHITE...WHITFIELD...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING ZONES:
BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...COBB...DADE...DAWSON...
FANNIN...FLOYD...FORSYTH...GILMER...GORDON...HARALSON...
LUMPKIN...MURRAY...NORTH FULTON...PAULDING...PICKENS...POLK...
TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
&&
$$
SHORT TERM...ARG
LONG TERM....11
AVIATION...ARG
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1043 AM EST WED JAN 30 2013
.UPDATE...
HAVE MADE UPDATES TO THE WEATHER AND POP GRIDS...AND SLOWED DOWN
THE CURRENT TIMING OF THE SQUALL LINE. WE ARE STARTING TO SEE
ISOLATED SUPERCELLS OUT FRONT OF THE MAIN LINE. THERE IS AN
ESPECIALLY STRONG TO SEVERE CELL IN EAST CENTRAL ALABAMA. WE ARE
STILL ON TRACK FOR SEVERE THUNDERSTORMS TODAY THROUGH THE AREA.
THE MAIN LINE IS EXPECTED TO PUSH THROUGH THE STATE WITH STRONG
WINDS BEING THE MAIN THREAT. THERE IS ALSO A RISK OF TORNADOES
WITH THESE STORMS...ESPECIALLY ANY SUPERCELLS OUT IN FRONT OF THE
LINE. DID ADJUST THE TEMPERATURES DOWN A FEW DEGREES AS THEY WERE
FORECAST WARMER THAN WHAT WAS GOING ON.
NO OTHER UPDATES ARE EXPECTED AT THIS TIME.
ARG
&&
.PREV DISCUSSION... /ISSUED 647 AM EST WED JAN 30 2013/
PREV DISCUSSION... /ISSUED 621 AM EST WED JAN 30 2013/
UPDATE...
SECOND UPDATE TO INCLUDE EXPANDED TORNADO WATCH 17 AREA IN THE
FFC WATCHES/WARNINGS/ADVISORIES SECTION BELOW.
BELANGER
PREV DISCUSSION... /ISSUED 410 AM EST WED JAN 30 2013/
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER VALUES...
1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN PREV SVR
EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
AVIATION...
12Z UPDATE...
STILL MONITORING LINE OF STRONG TSRA THAT WILL MOVE ACROSS THE
STATE TODAY AND THIS EVENING. TIMING HAS SHIFTED SLIGHTLY AND NOW
APPEARS TSRA WILL AFFECT ATL METRO 19Z-23Z. EXPECT STRONG
CROSSWIND AT E-W RUNWAY AIRPORTS TODAY...GUSTS COULD APPROACH
32KTS AT KATL. CIGS SHOULD STAY RIGHT NEAR IFR THRESHOLD AT KATL
AND REMAIN JUST ABOVE IFR ELSEWHERE. EXPECT END TO CIGS AND PRECIP
AROUND 23-00Z. STRONG WEST WINDS WILL CONTINUE OVERNIGHT AND
THURS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON IFR CIGS THIS MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
TORNADO WATCH UNTIL 4 PM EST THIS AFTERNOON FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...DADE...
DAWSON...DEKALB...DOOLY...DOUGLAS...FANNIN...FAYETTE...FLOYD...
FORSYTH...GILMER...GORDON...GREENE...GWINNETT...HALL...HANCOCK...
HARALSON...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JONES...LAMAR...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...MORGAN...MURRAY...MUSCOGEE...NEWTON...
NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TOWNS...TROUP...TWIGGS...UNION...UPSON...
WALKER...WALTON...WEBSTER...WHITE...WHITFIELD...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES:
BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...COBB...DADE...DAWSON...
FANNIN...FLOYD...FORSYTH...GILMER...GORDON...HARALSON...
LUMPKIN...MURRAY...NORTH FULTON...PAULDING...PICKENS...POLK...
TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
&&
$$
SHORT TERM...ARG
LONG TERM....31
AVIATION...ARG
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
647 AM EST WED JAN 30 2013
.PREV DISCUSSION... /ISSUED 621 AM EST WED JAN 30 2013/
UPDATE...
SECOND UPDATE TO INCLUDE EXPANDED TORNADO WATCH 17 AREA IN THE
FFC WATCHES/WARNINGS/ADVISORIES SECTION BELOW.
BELANGER
PREV DISCUSSION... /ISSUED 410 AM EST WED JAN 30 2013/
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER VALUES...
1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN PREV SVR
EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
&&
.AVIATION...
12Z UPDATE...
STILL MONITORING LINE OF STRONG TSRA THAT WILL MOVE ACROSS THE
STATE TODAY AND THIS EVENING. TIMING HAS SHIFTED SLIGHTLY AND NOW
APPEARS TSRA WILL AFFECT ATL METRO 19Z-23Z. EXPECT STRONG
CROSSWIND AT E-W RUNWAY AIRPORTS TODAY...GUSTS COULD APPROACH
32KTS AT KATL. CIGS SHOULD STAY RIGHT NEAR IFR THRESHOLD AT KATL
AND REMAIN JUST ABOVE IFR ELSEWHERE. EXPECT END TO CIGS AND PRECIP
AROUND 23-00Z. STRONG WEST WINDS WILL CONTINUE OVERNIGHT AND
THURS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON IFR CIGS THIS MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES:
BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...COBB...DADE...DAWSON...
FANNIN...FLOYD...FORSYTH...GILMER...GORDON...HARALSON...
LUMPKIN...MURRAY...NORTH FULTON...PAULDING...PICKENS...POLK...
TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
TORNADO WATCH UNTIL 1 PM EST THIS AFTERNOON FOR THE FOLLOWING
ZONES: BARTOW...CARROLL...CATOOSA...CHATTOOGA...DADE...FLOYD...
GORDON...HARALSON...HEARD...MURRAY...PAULDING...POLK...WALKER...
WHITFIELD.
&&
$$
SHORT TERM...SNELSON
LONG TERM....31
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
621 AM EST WED JAN 30 2013
.UPDATE...
SECOND UPDATE TO INCLUDE EXPANDED TORNADO WATCH 17 AREA IN THE
FFC WATCHES/WARNINGS/ADVISORIES SECTION BELOW.
BELANGER
&&
PREV DISCUSSION... /ISSUED 410 AM EST WED JAN 30 2013/
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER
VALUES...1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN
PREV SVR EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE
GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
AVIATION...
06Z UPDATE...
MAIN CONCERN IS TIMING OF TSRA THIS AFTERNOON. WELL DEFINED LINE
OF TSRA WILL MOVE THRU FROM WEST TO EAST...IMPACTING ATL METRO
AIRPORTS AROUND 18Z-22Z. SHOULD SEE WIDESPREAD -SHRA DEVELOPING A
FEW HOURS BEFORE THEN AND POSSIBLY CONTINUING AFTER LINE OF TSRA
HAS MOVED THRU. OTHER CONCERN TODAY IS STRONG CROSSWINDS AT
AIRPORTS WITH E-W RUNWAY CONFIGURATION...INCLUDING KATL WHERE
CROSSWIND COMPONENT GUSTS 16Z-22Z COULD APPROACH 30KTS. IFR CIGS
LIKELY AT MOST AIRPORTS FROM 09Z THRU 14Z THOUGH MAY BE TOO WARM
OVER MIDDLE GA AIRPORTS FOR CIGS TO GET DOWN TO IFR. CIGS WILL
IMPROVE AFTER LINE OF TSRA MOVES THRU...AROUND 22Z AT ATL...THEN
CLEAR ENTIRELY AFTER 06Z-09Z THURS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON IFR CIGS THIS MORNING AND TSRA TIMING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES:
BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...COBB...DADE...DAWSON...
FANNIN...FLOYD...FORSYTH...GILMER...GORDON...HARALSON...
LUMPKIN...MURRAY...NORTH FULTON...PAULDING...PICKENS...POLK...
TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
TORNADO WATCH UNTIL 1 PM EST THIS AFTERNOON FOR THE FOLLOWING
ZONES: BARTOW...CARROLL...CATOOSA...CHATTOOGA...DADE...FLOYD...
GORDON...HARALSON...HEARD...MURRAY...PAULDING...POLK...WALKER...
WHITFIELD.
&&
$$
SHORT TERM...SNELSON
LONG TERM....31
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
555 AM EST WED JAN 30 2013
.UPDATE...
UPDATE TO INCLUDE TORNADO WATCH 17 AREA IN THE FFC
WATCHES/WARNINGS/ADVISORIES SECTION BELOW.
BELANGER
&&
.PREV DISCUSSION... /ISSUED 410 AM EST WED JAN 30 2013/
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER
VALUES...1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN
PREV SVR EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE
GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
AVIATION...
06Z UPDATE...
MAIN CONCERN IS TIMING OF TSRA THIS AFTERNOON. WELL DEFINED LINE
OF TSRA WILL MOVE THRU FROM WEST TO EAST...IMPACTING ATL METRO
AIRPORTS AROUND 18Z-22Z. SHOULD SEE WIDESPREAD -SHRA DEVELOPING A
FEW HOURS BEFORE THEN AND POSSIBLY CONTINUING AFTER LINE OF TSRA
HAS MOVED THRU. OTHER CONCERN TODAY IS STRONG CROSSWINDS AT
AIRPORTS WITH E-W RUNWAY CONFIGURATION...INCLUDING KATL WHERE
CROSSWIND COMPONENT GUSTS 16Z-22Z COULD APPROACH 30KTS. IFR CIGS
LIKELY AT MOST AIRPORTS FROM 09Z THRU 14Z THOUGH MAY BE TOO WARM
OVER MIDDLE GA AIRPORTS FOR CIGS TO GET DOWN TO IFR. CIGS WILL
IMPROVE AFTER LINE OF TSRA MOVES THRU...AROUND 22Z AT ATL...THEN
CLEAR ENTIRELY AFTER 06Z-09Z THURS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON IFR CIGS THIS MORNING AND TSRA TIMING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH FROM 9 AM EST THIS MORNING THROUGH THIS EVENING FOR
THE FOLLOWING ZONES: BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...
COBB...DADE...DAWSON...FANNIN...FLOYD...FORSYTH...GILMER...
GORDON...HARALSON...LUMPKIN...MURRAY...NORTH FULTON...PAULDING...
PICKENS...POLK...TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
TORNADO WATCH UNTIL 1 PM EST THIS AFTERNOON FOR THE FOLLOWING
ZONES: CATOOSA...DADE...MURRAY...WALKER...WHITFIELD.
&&
$$
SHORT TERM...SNELSON
LONG TERM....BELANGER
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
410 AM EST WED JAN 30 2013
.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
PRIMARY CONCERN IS THREAT AND TIMING OF SEVERE CONVECTION THIS
AFTERNOON AND EARLY EVENING. VERY IMPRESSIVE STORM SYSTEM
APPROACHING THE STATE THIS MORNING. WHILE FAVORABLE SIG TOR
PARAMETER VALUES CURRENTLY CONFINED TO AREA CLOSER TO THE COAST
BASED ON RAP ANALYSES...HAVE SEEN A FEW REPORTS OF WIND DAMAGE
FURTHER NORTH OVER WRN TN AND NRN MS IN LOW CAPE AREAS. IF MODELS
ARE TO BE BELIEVED...PARAMETERS SHOULD BE MORE FAVORABLE HERE THAN
WHAT IS CURRENTLY SHOWN TO THE WEST. 00Z MODELS HAVE SLOWED TIMING
OF MAIN LINE OF TSRA SOMEWHAT WITH NAM SLOWEST. 06Z NAM ALSO
CONTINUING SLOWER TREND. LINE SHOULD MOVE INTO NW CORNER OF CWA
AROUND 10AM... I-85 BY 3PM AND AHN-MCN-AMERICUS LINE BY 7PM AND
EXITING SE CORNER OF CWA AROUND 10PM. INGREDIENTS STILL APPEAR
SUFFICIENT FOR AT LEAST ISOLD AREAS OF WIND DMG OR BRIEF TORNADOES.
AS OFTEN THE CASE...06Z NAM MLCAPE SHOWING MORE INSTABILITY THAN
OTHER MODELS WITH VALUES AROUND 400-700 J/KG. 00Z GFS HAS 200-400
J/KG OVER ALL BUT NE GA. VERTICAL WIND SHEAR WILL BE VERY STRONG.
0-1KM BULK SHEAR 40-50KTS SEEN ON GFS AND NAM. FAVORABLE CIN...LCL
AND DEEP LAYER SHEAR YIELDING DECENT SIG TOR PARAMETER
VALUES...1-2 WITH GFS AND 2-5 ON NAM. THIS VALUES ARE HIGHER THAN
PREV SVR EVENT ON DEC 26 WHEN WE SAW 3 WEAK TORNADOES IN MIDDLE
GA.
WINDS STILL SHOULD KEEP MOST OF AREA IN ADV CRITERIA TODAY AND THIS
EVENING. HAVE EXTENDED WIND ADV TIL MIDNIGHT. HIGH WIND WARNING
CRITERIA NOT QUITE BEING MET IN LATEST MODEL GRIDS...BUT VERY CLOSE.
WITH WET SOILS DEVELOPING QUICKLY THIS AFTERNOON...HAVE CONTINUED
WIND WARNING THRU 6PM...AFTER WHICH TIME LLJ WILL SHIFT EAST OF THE
NE GA MOUNTAINS.
HEAVY RAIN WILL ALSO BE SIGNIFICANT THREAT. AGREE WITH LATEST HPC
GUIDANCE WHICH HAS BUMPED UP EVENT TOTAL PRECIP TO 1 TO 2 INCHES
WITH SOME AREAS OF NE GA APPROACHING 2.5 INCHES...DUE TO SLOWER
TIMING AND PROGRESSION OF TSRA. SFC DEWPOINTS HAVE BEEN HIGHER THAN
FCST LAST SEVERAL HOURS AS WELL. BASED ON LATEST GRIDDED FFG AND
QPF...HAVE EXPANDED FLOOD WATCH SOUTH TO AREAS NORTH OF A FRANKLIN
TO ROSWELL TO CLEVELAND LINE.
FINALLY...ANOTHER LOW AMPLITUDE SHORT WAVE PROGGED TO MOVE ALONG
LONG WAVE TROUGH OVER TN VALLEY THURS NIGHT. WITH COLD AIR IN
PLACE...ESP ALOFT...COULD SEE SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS. NO IMPACTS EXPECTED.
SNELSON
.LONG TERM /FRIDAY THROUGH TUESDAY/...
EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG
TERM...WITH LONG WAVE UPPER-LEVEL TROUGH SITUATED OVER THE EASTERN
U.S. THOUGH EARLY NEXT WEEK. GENERALLY...NORTHWEST FLOW WILL
PERSIST OVER THE REGION...AND MODELS CONTINUE TO ADVERTISE A
SERIES OF UPPER LEVEL SHORT WAVES IMPACTING THE AREA AS A RESULT.
THE FIRST DISTURBANCE OCCURS AT THE TAIL END OF THE SHORT TERM
PERIODS...AND WHAT MOISTURE QUICKLY DISSIPATES INTO THE LONG TERM
EARLY FRIDAY.
THE SECOND DISTURBANCE LOOKS TO APPROACH THE AREA LATE SATURDAY
AND REMAIN ACROSS FAR NORTH GEORGIA EARLY SUNDAY...WITH SLIGHTLY
MORE MOISTURE AVAILABLE THAN THE PREVIOUS SHORTWAVE. FOR
NOW...WITH THE LATEST MODEL TIMING FOR THIS SYSTEM...LOOKS LIKE IT
WILL PRIMARILY BE RAIN...WITH SOME POSSIBILITY OF A RAIN-SNOW MIX
INTO SUNDAY MORNING. HAVE GENERALLY GONE WITH SLIGHT CHANCE
POPS...AND HAVE KEPT NO ACCUMULATIONS FOR NORTH GEORGIA.
HAVE SCALED BACK POPS SLIGHTLY FOR THE THIRD SHORT WAVE EXPECTED
MONDAY NIGHT INTO TUESDAY. LATEST MODEL RUNS ARE LESS ENTHUSIASTIC
WITH THE FRONTAL SUPPORT...AND THEREFORE LESS AGGRESSIVE WITH
MOISTURE AND PRECIP POTENTIAL. HAVE CONTINUED WITH SLIGHT CHANCE
POPS MONDAY NIGHT AND TUESDAY...AND QUICKLY DROP POPS OFF INTO
TUESDAY NIGHT.
BELANGER
&&
.FIRE WEATHER...
AS DRY AIR PLUNGES IN BEHIND FRONT...HUMIDITY PROGGED TO DROP TO 22
TO 25 PCT FOR A FEW HOURS THURS AFTERNOON OVER MIDDLE GA. WITH 1 TO
2 INCHES OF RAIN EXPECTED TODAY...FUELS ARE EXPECTED TO BE TOO WET
TO REQUIRE ANY FIRE DANGER STATEMENTS.
SNELSON
&&
.AVIATION...
06Z UPDATE...
MAIN CONCERN IS TIMING OF TSRA THIS AFTERNOON. WELL DEFINED LINE
OF TSRA WILL MOVE THRU FROM WEST TO EAST...IMPACTING ATL METRO
AIRPORTS AROUND 18Z-22Z. SHOULD SEE WIDESPREAD -SHRA DEVELOPING A
FEW HOURS BEFORE THEN AND POSSIBLY CONTINUING AFTER LINE OF TSRA
HAS MOVED THRU. OTHER CONCERN TODAY IS STRONG CROSSWINDS AT
AIRPORTS WITH E-W RUNWAY CONFIGURATION...INCLUDING KATL WHERE
CROSSWIND COMPONENT GUSTS 16Z-22Z COULD APPROACH 30KTS. IFR CIGS
LIKELY AT MOST AIRPORTS FROM 09Z THRU 14Z THOUGH MAY BE TOO WARM
OVER MIDDLE GA AIRPORTS FOR CIGS TO GET DOWN TO IFR. CIGS WILL
IMPROVE AFTER LINE OF TSRA MOVES THRU...AROUND 22Z AT ATL...THEN
CLEAR ENTIRELY AFTER 06Z-09Z THURS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON IFR CIGS THIS MORNING AND TSRA TIMING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 38 50 33 / 100 100 5 5
ATLANTA 67 35 49 33 / 100 60 5 5
BLAIRSVILLE 61 32 43 27 / 100 60 5 20
CARTERSVILLE 67 34 47 31 / 100 40 5 10
COLUMBUS 72 38 56 39 / 100 70 5 5
GAINESVILLE 63 35 47 32 / 100 70 5 10
MACON 73 39 55 33 / 90 100 5 5
ROME 68 33 48 31 / 100 40 5 10
PEACHTREE CITY 68 36 51 32 / 100 60 5 5
VIDALIA 80 46 59 36 / 70 90 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FLOYD...FORSYTH...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...MACON...MADISON...MARION...MERIWETHER...MONROE...
MONTGOMERY...MORGAN...MUSCOGEE...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PEACH...PIKE...POLK...PULASKI...
PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...STEWART...
SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...
TREUTLEN...TROUP...TWIGGS...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITFIELD...WILCOX...WILKES...
WILKINSON.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR THE FOLLOWING
ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WHITE.
FLOOD WATCH FROM 9 AM EST THIS MORNING THROUGH THIS EVENING FOR
THE FOLLOWING ZONES: BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...
COBB...DADE...DAWSON...FANNIN...FLOYD...FORSYTH...GILMER...
GORDON...HARALSON...LUMPKIN...MURRAY...NORTH FULTON...PAULDING...
PICKENS...POLK...TOWNS...UNION...WALKER...WHITE...WHITFIELD.
WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
THE FOLLOWING ZONES: DAWSON...FANNIN...GILMER...LUMPKIN...
MURRAY...PICKENS...TOWNS...UNION...WHITE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....BELANGER
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
403 AM EST WED JAN 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST TODAY AS STRONG WEATHER SYSTEM
WITH STRONG COLD FRONT MOVE TOWARD THE REGION. BOTH MOISTURE
AND WINDS WILL INCREASE WITH SHOWERS AND POSSIBLE AFTERNOON
AND EVENING THUNDERSTORMS. WARM AIR TODAY WITH HIGHS UP AROUND
80. AFTER THE COLD FRONT PASSES TONIGHT...IT WILL TURN SHARPLY
COLDER AND HIGHS THURSDAY WILL BE ALMOST 30 DEGREES COLDER.
HIGH PRESSURE FRIDAY AND SATURDAY WILL PROVIDE DRY CHILLY WEATHER
WITH BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THROUGH MID MORNING...UPPER RIDGE TEMPORARILY HOLDING SHOWERS TO
THE WEST AND NORTH. BUT RIDGE WILL WEAKEN AND MOVE EAST FOR THE
REMAINDER OF THE NIGHT. CAE 88D JUST SHOWING SOME LIGHT SHOWERS
NORTHWEST OF HERE IN THE GSP CWA. REGIONAL RADARS SHOWING SHOWER
COVERAGE INCREASING IN GEORGIA. ACTIVITY WILL MOVE TO THE EAST
THOUGH AS INDICATED BY RUC13. RUC MODEL HAS SHOWERS ENTERING
WESTERN PART OF CAE CWA IN THE CSRA 10-12Z TIME FRAME. JUST
SHOWERS THIS MORNING BUT THUNDERSTORMS ARE POSSIBLE CLOSER TO MID
DAY` OVER THE REGION. INCREASING WIND FLOW AT SURFACE WITH
SOUTHERLY WINDS 10-20 MPH. TEMPERATURES HOLDING ABOUT 64-65
DEGREES WITH INCREASING INSTABILITY BUT LIS STILL POSITIVE AT
+3/+4/.
TODAY...DEEP TROUGH TO THE WEST WILL SHIFT EASTWARD ACROSS THE
MISSISSIPPI VALLEY AND PUSH A COLD FRONT INTO THE CAROLINAS LATE
THIS AFTERNOON. AHEAD OF THIS SYSTEM...MOISTURE FLUX WILL INCREASE
WITH GFS MODEL PWS INCREASING TO 1.60 INCHES. SIGNIFICANT 500MB
HEIGHT FALLS WILL PRECEDE THE UPPER TROUGH AS THE RIGHT ENTRANCE
REGION OF AN ASSOCIATED 150KT UPPER JET SHIFTS OVER THE SOUTHEAST
STATES. FORECAST MODELS ARE IN AGREEMENT ALSO SHOWING A VERY
STRONG...NEARLY 75KT 850MB JET SHIFTING OVER THE CAROLINAS DURING
THE AFTERNOON. TEMPERATURES ARE EXPECTED TO SURGE TO AROUND 80
IN THE AFTERNOON WITH DEWPOINTS HOLDING IN THE LOWER 60S. INSTABILITY
APPEARS TO BE LIMITED BUT WIND SHEAR WILL BE EXTREME AND THIS
LOOKS LIKE A CLASSIC HIGH SHEAR LOW CAPE (HSLC) ENVIRONMENT. DUE
TO THE STRONG WINDS AND POTENTIAL FOR STRONG WINDS TO REACH THE
SURFACE AND WILL CONTINUE THE WIND ADVISORY FROM 11AM WEDNESDAY
THROUGH 6 AM THURSDAY MORNING.
ALL OF THESE FACTORS LEAD TO REASONABLY HIGH CONFIDENCE THAT THERE
WILL BE A LINE OF CONVECTION ALONG OR JUST AHEAD OF THE FRONT THAT
WILL BE CAPABLE OF MIXING DOWN VERY STRONG WINDS TO THE SURFACE.
SPC CONTINUES TO OUTLOOK THE AREA IN A SLIGHT RISK FOR SEVERE
WEATHER WITH DAMAGING WINDS BEING THE MAIN THREAT. TIME FRAME IS
LATE AFTERNOON INTO THE EVENING HOURS. WILL CONTINUE CATEGORICAL
POPS FROM WEST TO EAST LATE AFTERNOON THROUGH EARLY EVENING.
PRECIPITATION AMOUNTS SHOULD BE LIMITED BY SPEED OF THE SYSTEM
BUT COULD SEE A QUARTER TO THREE QUARTERS OF AN INCH ACROSS THE
AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
STRONG UPPER DYNAMICS WILL CONTINUE DURING THE EVENING HOURS
UNTIL FRONTAL PASSAGE NEAR 9-10 PM TIME FRAME THIS EVENING.
THE STRONG LLJ OF AROUND 75KT WILL CONTINUE AS WELL. LOCAL
MODELS INDICATE POSSIBLY A SQUALL LINE 6-8 PM TIME FRAME AND
CONDITIONS MAY BE FAVORABLE FOR STRONG WINDS TO REACH THE
SURFACE LATE IN THE AFTERNOON OR IN THE EVENING BEFORE THE
COLD FRONT MOVES THROUGH. 20KM NAM IS GIVING LIS AROUND -2
DURING THIS TIME BUT NAM BUFR SOUNDING HAS VERY LOW CAPES
BELOW 200 J/KG AT THIS TIME AND THIS LOOKS LIKE A CLASSIC HIGH
SHEAR LOW CAPE ENVIRONMENT. SPC CONTINUES SLIGHT RISK OF SEVERE
STORMS FOR THE AREA WITH THE MAIN THREAT FROM DAMAGING WINDS.
CONTINUING WITH CATEGORICAL POPS FROM WEST TO EAST THROUGH EARLY
EVENING. AGAIN...PRECIPITATION AMOUNTS SHOULD BE LIMITED BY SPEED
OF THE SYSTEM BUT COULD SEE A QUARTER TO THREE QUARTERS OF AN
INCH ACROSS THE AREA.
BEHIND THE FRONT...COOL HIGH PRESSURE WILL BUILD INTO THE REGION
LATE WEDNESDAY NIGHT AND THURSDAY AS SKIES CLEAR FROM WEST TO EAST
AND TEMPERATURES FALL INTO THE 40S. HIGH PRESSURE WILL RESIDE OVER
THE AREA THROUGH THE END OF THE PERIOD WITH A GRADIENT IN MAX
TEMPS THU/FRI FROM LOWER 50S NORTH TO UPPER 50S SOUTH. ANOTHER
SHORTWAVE WILL CROSS THE OHIO VALLEY TO OUR NORTH ON FRIDAY AND
BRING A DRY COLD FRONT THROUGH BY FRIDAY EVENING...LEADING TO
BELOW NORMAL OVERNIGHT LOWS FRIDAY NIGHT IN THE 20S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE EXTENDED FORECAST WILL FEATURE AN ACTIVE WEATHER PATTERN AS
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SHOWING A MEAN
NORTHWESTERLY 500MB FLOW WITH A SERIES OF SHORTWAVES MOVING OVER THE
REGION. SURFACE HIGH PRESSURE WILL BE IN PLACE SATURDAY WITH
WESTERLY UPPER FLOW...RESULTING IN MOSTLY SUNNY SKIES AND NEAR TO
SLIGHTLY ABOVE NORMAL TEMPERATURES.
THE FIRST SHORTWAVE TO CROSS THE REGION WILL TRACK SOUTHEASTWARD
ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC REGION SATURDAY
NIGHT...PUSHING A COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY
MORNING. MOISTURE WILL BE LIMITED WITH THIS FRONT AND LITTLE IF ANY
PRECIPITATION IS EXPECTED. MOST OF THE COLD AIR WILL REMAIN NORTH OF
THE MIDLANDS AS HIGH PRESSURE BUILDS INTO THE AREA SUNDAY AND
MONDAY. FAIR SKIES AND ABOVE NORMAL TEMPERATURES ARE EXPECTED
SUNDAY AND MONDAY WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND LOWS
IN THE 30S.
A SECOND SHORTWAVE TROUGH WILL FOLLOW A SIMILAR PATH ACROSS THE OHIO
VALLEY TO THE MID ATLANTIC IN NORTHWESTERLY UPPER FLOW ON MONDAY
NIGHT INTO TUESDAY. AGAIN A COLD FRONT WILL PUSH THROUGH THE REGION
SOMETIME TUESDAY MORNING. MOISTURE WILL BE LIMITED WITH THIS FRONT
AS WELL AND PRECIPITATION CHANCES ARE EXPECTED TO BE LOW.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
EXPECT IFR CEILINGS WILL DEVELOP OVERNIGHT BECAUSE OF HIGH LOW-
LEVEL MOISTURE AHEAD OF THE APPROACHING WEAK WARM FRONT. THE NAM
AND GFS MOS ARE IN GOOD AGREEMENT INDICATING IFR CEILINGS. FOG
SHOULD BE LIMITED BY INCREASING BOUNDARY LAYER WIND. LOW-LEVEL
WIND SHEAR WILL OCCUR. THE MODELS INDICATE WINDS INCREASING TO
AROUND 40 KNOTS AT 2000 FEET. THE WARM FRONT SHOULD LIFT NORTH OF
THE AREA EARLY WEDNESDAY WITH STRONG HEATING AND MIXING AHEAD OF
THE APPROACHING COLD FRONT. CEILINGS SHOULD IMPROVE. WINDS WILL BE
ON THE INCREASE AHEAD OF THE APPROACHING COLD FRONT. EXPECT A LINE
OF SHOWERS WILL DEVELOP AHEAD OF THE FRONT. THERE MAY ALSO BE
THUNDERSTORMS. AN AVERAGE OF THE NAM AND GFS SUPPORTS SHOWERS
BECOMING LIKELY BEGINNING AROUND 22Z. WINDS WILL BE STRONG AND
GUSTY ESPECIALLY NEAR ANY SHOWERS OR THUNDERSTORMS. WINDS OVER 30
KNOTS MAY OCCUR.
EXTENDED AVIATION OUTLOOK...SHOWERS AND POSSIBLY THUNDERSTORMS
WILL CONTINUE INTO WEDNESDAY NIGHT. WINDS OVER 30S KNOTS MAY OCCUR
ESPECIALLY NEAR ANY SHOWERS AND THUNDERSTORMS. IT WILL BE BREEZY
BEHIND THE COLD FRONT THURSDAY. NO SIGNIFICANT IMPACTS EXPECTED
DURING THE REST OF THE OUTLOOK PERIOD.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST THURSDAY FOR
SCZ015-016-018-020>022-025>031-035>038-041.
GA...WIND ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST THURSDAY FOR
GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
248 AM EST WED JAN 30 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL MOVE EAST OVERNIGHT. A STRONG
COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY AND SWEEP THROUGH
THE AREA WEDNESDAY EVENING. WINDS WILL BE STRONG AHEAD OF THE
FRONT WEDNESDAY AFTERNOON AND SEVERE WEATHER IS POSSIBLE AS THE
FRONT PASSES. HIGH PRESSURE WILL RETURN FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPPER RIDGE TEMPORARILY HOLDING SHOWERS TO THE WEST AND NORTH.
BUT RIDGE WILL WEAKEN AND MOVE EAST FOR THE REMAINDER OF THE
NIGHT. CAE 88D JUST SHOWING SOME LIGHT SHOWERS NORTHWEST OF
HERE IN THE GSP CWA. REGIONAL RADARS SHOWING SHOWER COVERAGE
INCREASING IN GEORGIA. ACTIVITY WILL MOVE TO THE EAST THOUGH
AS INDICATED BY RUC13. RUC MODEL HAS SHOWERS ENTERING WESTERN
PART OF CAE CWA IN THE CSRA 10-12Z TIME FRAME. JUST SHOWERS
THIS MORNING BUT THUNDERSTORMS ARE POSSIBLE CLOSER TO MID DAY`
OVER THE REGION. INCREASING WIND FLOW AT SURFACE WITH SOUTHERLY
WINDS 10-20 MPH. TEMPERATURES HOLDING ABOUT 64-65 DEGREES WITH
INCREASING INSTABILITY BUT LIS STILL POSITIVE AT +3/+4/.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
DEEP TROUGH OVER THE INTERMOUNTAIN WEST TODAY WILL SHIFT EASTWARD
ACROSS THE MISSISSIPPI VALLEY ON WEDNESDAY WHICH WILL PUSH A
COLD FRONT INTO THE CAROLINAS LATE WEDNESDAY AFTERNOON AND CROSS
THE REGION WEDNESDAY NIGHT. AHEAD OF THIS SYSTEM...THE UPPER RIDGE
AXIS WILL SHIFT OFF THE COAST AS THE SURFACE RIDGE WEAKENS WITH
DEEP SOUTH TO SOUTHWESTERLY FLOW.
SIGNIFICANT 500MB HEIGHT FALLS WILL PRECEDE THE UPPER TROUGH AS
THE RIGHT ENTRANCE REGION OF AN ASSOCIATED 150KT UPPER JET SHIFTS
OVER THE SOUTHEASTERN STATES LATE WEDNESDAY AFTERNOON AND EVENING.
FORECAST MODELS ARE IN AGREEMENT ALSO SHOWING A VERY
STRONG...NEARLY 75KT 850MB JET SHIFTING OVER THE CAROLINAS DURING
THE AFTERNOON AND EARLY EVENING HOURS. TEMPERATURES ARE EXPECTED
TO SURGE INTO THE MID TO UPPER 70S WITH DEWPOINTS PUSHING INTO THE
LOWER TO MID 60S. PWAT VALUES ARE FORECAST TO APPROACH 1.60-1.70
INCHES JUST AHEAD OF THE FRONT...WHICH IS ABOVE THE 99TH
PERCENTILE. INSTABILITY APPEARS TO BE LIMITED BUT WIND SHEAR WILL
BE EXTREME AND THIS LOOKS LIKE A CLASSIC HIGH SHEAR LOW CAPE
(HSLC) ENVIRONMENT. DUE TO THE STRONG WINDS AND POTENTIAL FOR
STRONG WINDS TO REACH THE SURFACE...AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL ISSUE A WIND ADVISORY FROM 11AM
WEDNESDAY THROUGH 6 AM THURSDAY MORNING.
ALL OF THESE FACTORS LEAD TO REASONABLY HIGH CONFIDENCE THAT THERE
WILL BE A LINE OF CONVECTION ALONG OR JUST AHEAD OF THE FRONT THAT
WILL BE CAPABLE OF MIXING DOWN VERY STRONG WINDS TO THE SURFACE.
SPC CONTINUES TO OUTLOOK THE AREA IN A SLIGHT RISK FOR SEVERE
WEATHER WITH DAMAGING WINDS BEING THE MAIN THREAT. TIME FRAME FOR
THE CONVECTION TO MOVE THROUGH THE FORECAST AREA LOOKS TO BE
BETWEEN 22Z-06Z. CONTINUING WITH CATEGORICAL POPS FROM WEST TO
EAST LATE AFTERNOON THROUGH EARLY EVENING WEDNESDAY. PRECIPITATION
AMOUNTS SHOULD BE LIMITED BY SPEED OF THE SYSTEM BUT COULD SEE A
QUARTER TO THREE QUARTERS OF AN INCH ACROSS THE AREA.
BEHIND THE FRONT...COOL HIGH PRESSURE WILL BUILD INTO THE REGION
LATE WEDNESDAY NIGHT AND THURSDAY AS SKIES CLEAR FROM WEST TO EAST
AND TEMPERATURES FALL INTO THE 40S. HIGH PRESSURE WILL RESIDE OVER
THE AREA THROUGH THE END OF THE PERIOD WITH A GRADIENT IN MAX
TEMPS THU/FRI FROM LOWER 50S NORTH TO UPPER 50S SOUTH. ANOTHER
SHORTWAVE WILL CROSS THE OHIO VALLEY TO OUR NORTH ON FRIDAY AND
BRING A DRY COLD FRONT THROUGH BY FRIDAY EVENING...LEADING TO
BELOW NORMAL OVERNIGHT LOWS FRIDAY NIGHT IN THE 20S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE EXTENDED FORECAST WILL FEATURE AN ACTIVE WEATHER PATTERN AS
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SHOWING A MEAN
NORTHWESTERLY 500MB FLOW WITH A SERIES OF SHORTWAVES MOVING OVER THE
REGION. SURFACE HIGH PRESSURE WILL BE IN PLACE SATURDAY WITH
WESTERLY UPPER FLOW...RESULTING IN MOSTLY SUNNY SKIES AND NEAR TO
SLIGHTLY ABOVE NORMAL TEMPERATURES.
THE FIRST SHORTWAVE TO CROSS THE REGION WILL TRACK SOUTHEASTWARD
ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC REGION SATURDAY
NIGHT...PUSHING A COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY
MORNING. MOISTURE WILL BE LIMITED WITH THIS FRONT AND LITTLE IF ANY
PRECIPITATION IS EXPECTED. MOST OF THE COLD AIR WILL REMAIN NORTH OF
THE MIDLANDS AS HIGH PRESSURE BUILDS INTO THE AREA SUNDAY AND
MONDAY. FAIR SKIES AND ABOVE NORMAL TEMPERATURES ARE EXPECTED
SUNDAY AND MONDAY WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND LOWS
IN THE 30S.
A SECOND SHORTWAVE TROUGH WILL FOLLOW A SIMILAR PATH ACROSS THE OHIO
VALLEY TO THE MID ATLANTIC IN NORTHWESTERLY UPPER FLOW ON MONDAY
NIGHT INTO TUESDAY. AGAIN A COLD FRONT WILL PUSH THROUGH THE REGION
SOMETIME TUESDAY MORNING. MOISTURE WILL BE LIMITED WITH THIS FRONT
AS WELL AND PRECIPITATION CHANCES ARE EXPECTED TO BE LOW.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
EXPECT IFR CEILINGS WILL DEVELOP OVERNIGHT BECAUSE OF HIGH LOW-
LEVEL MOISTURE AHEAD OF THE APPROACHING WEAK WARM FRONT. THE NAM
AND GFS MOS ARE IN GOOD AGREEMENT INDICATING IFR CEILINGS. FOG
SHOULD BE LIMITED BY INCREASING BOUNDARY LAYER WIND. LOW-LEVEL
WIND SHEAR WILL OCCUR. THE MODELS INDICATE WINDS INCREASING TO
AROUND 40 KNOTS AT 2000 FEET. THE WARM FRONT SHOULD LIFT NORTH OF
THE AREA EARLY WEDNESDAY WITH STRONG HEATING AND MIXING AHEAD OF
THE APPROACHING COLD FRONT. CEILINGS SHOULD IMPROVE. WINDS WILL BE
ON THE INCREASE AHEAD OF THE APPROACHING COLD FRONT. EXPECT A LINE
OF SHOWERS WILL DEVELOP AHEAD OF THE FRONT. THERE MAY ALSO BE
THUNDERSTORMS. AN AVERAGE OF THE NAM AND GFS SUPPORTS SHOWERS
BECOMING LIKELY BEGINNING AROUND 22Z. WINDS WILL BE STRONG AND
GUSTY ESPECIALLY NEAR ANY SHOWERS OR THUNDERSTORMS. WINDS OVER 30
KNOTS MAY OCCUR.
EXTENDED AVIATION OUTLOOK...SHOWERS AND POSSIBLY THUNDERSTORMS
WILL CONTINUE INTO WEDNESDAY NIGHT. WINDS OVER 30S KNOTS MAY OCCUR
ESPECIALLY NEAR ANY SHOWERS AND THUNDERSTORMS. IT WILL BE BREEZY
BEHIND THE COLD FRONT THURSDAY. NO SIGNIFICANT IMPACTS EXPECTED
DURING THE REST OF THE OUTLOOK PERIOD.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST THURSDAY FOR
SCZ015-016-018-020>022-025>031-035>038-041.
GA...WIND ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST THURSDAY FOR
GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
209 PM CST WED JAN 30 2013
.DISCUSSION...
944 AM CST
A WEAK SECONDARY SURFACE LOW IS MAKING ITS WAY THROUGH NORTHERN IL
THIS MORNING WITH ARCTIC AIR SLOWLY SPILLING INTO WESTERN IL.
FREEPORT IL HAS ALREADY TURNED OVER TO SNOW AND GETTING REPORTS
OF RAIN MIXING WITH SLEET FROM DIXON AND ROCKFORD. AS TEMPS FALL
TODAY EXPECTING RAIN TO QUICKLY CHANGE OVER TO SNOW WITH A BRIEF
PERIOD OF SLEET/ICE PELLETS POSSIBLE. NOT EXPECTING ANY
SIGNIFICANT IMPACTS FROM SLEET/ICE PELLETS.
FOR THE WINTER WEATHER ADVISORY FOR WINNEBAGO...OGLE...AND BOONE
COUNTIES...WILL KEEP IT GOING BUT THINKING THE BEST FORCING WILL
OCCUR WHEN TEMPS ARE ABOVE FREEZING. THE UPPER LEVEL JET STREAKS
LEFT EXIT REGION IS OVER NORTHERN IL WHILE THE SPC RAP AND OTHER
GUIDANCE INDICATE A BAND OF 850 MB FRONTOGENESIS EXTENDING FROM
SOUTHERN WI THROUGH MOLINE IL. NEGATIVE EPV LIES ABOVE THE
FRONTOGENESIS WHICH WOULD SUPPORT BANDS OF LOCALLY HEAVIER
SNOWFALL. HOWEVER...THE FRONTOGENESIS IS EXPECTED TO WEAKEN
SIGNIFICANTLY THROUGH THE EARLY AFTERNOON HOURS SO THINKING THE
HEAVIEST SNOW WILL FALL THROUGH 3PM AT THE LATEST ACROSS THE
ADVISORY AREA. GIVEN THAT RAIN IS JUST TURNING OVER TO SNOW
NOW...AGREE WITH THE PREVIOUS FORECAST THAT THE ADVISORY CRITERIA
WILL PROBABLY ONLY BE MET IN ISOLATED LOCATIONS. OVERALL EXPECTING
2-4 INCHES OF SNOW IN THE ADVISORY AREA WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IF A MESOSCALE BAND SETS UP OVER THE AREA.
AS TEMPS FALL THROUGH THE DAY RAIN WILL TURN OVER TO SNOW
THROUGHOUT THE DAY. ROUGH TIMINGS ARE ALL SNOW ACROSS THE ADVISORY
AREA BY NOON...NORTH OF I-55 BY 4-5 PM...CHICAGO BY 5-6 PM...AND
ALL SNOW ACROSS THE AREA BY 7-8PM. EXPECTING A WET SNOW AS IT
FIRST TURNS OVER THEN BECOMING A MORE AVERAGE SNOW LATE THIS
AFTERNOON/EVENING. ONCE AGAIN EXPECTING 2-4 INCHES IN THE
NORTHWEST CORNER OF THE CWA...1-2 INCHES NORTH OF A MENDOTA TO
WAUKEGAN LINE...AND LESS THAN AN INCH ELSEWHERE.
JEE
//PREV DISCUSSION...
353 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE POTENTIAL FOR SNOW
TODAY...CLOUD COVER AND ITS POTENTIAL IMPACTS ON TEMPS...AND CLIPPER
SYSTEM ARRIVING FRIDAY NIGHT INTO SATURDAY.
VERY TRICKY FORECAST TODAY AS COLDER AIR SPILLS INTO THE REGION AND
PORTIONS OF THE CWA POTENTIALLY GET CLIPPED BY TROWAL. HAVE OPTED TO
ISSUE A WINTER WX ADVISORY FOR MY NW 3 COUNTIES MOSTLY DUE TO MODEL
GUIDANCE AND TO MAKE A PRETTIER WATCH/WARNING/ADVISORY MAP BUT HAVE
SERIOUS DOUBTS ABOUT WHETHER IT WILL COME CLOSE TO VERIFYING BASED
ON CURRENT TRENDS IN OBSERVATIONAL DATA. WARM CONVEYOR BELT WITH
ITS MASSIVE STREAM OF RAIN CONTINUES TO SHIFT EASTWARD AND OUT OF
THE CWA EARLY THIS MORNING AND WOULD ANTICIPATE THIS TREND TO
CONTINUE AS WATER VAPOR IMAGERY SHOWS MASSIVE DEVELOPING MID LEVEL
DRY INTRUSION PUNCHING NORTHEAST INTO THE REGION. SURFACE ANALYSIS
HAS ANOTHER IN SEEMING CONGA LINE OF LOWS OVER MISSOURI STILL AT
09Z...AS THIS LOW TRANSLATES NORTHEAST INTO ILLINOIS EARLY THIS
MORNING IT WILL ACT TO SLOW THE INTRUSION OF COLD AIR AND LIKELY
DELAY THE RAIN/SNOW TRANSITION LINE FROM MAKING GOOD HEADWAY ACROSS
THE CWA UNTIL IT LIFTS OUT OF THE AREA TOWARD MIDDAY.
PROFILERS AND OBJECTIVE ANALYSIS HAVE A 120KT+ 500MB JET PUNCHING NE
INTO THE DRY INTRUSION WITH STRONG ASCENT TO THE LEFT OF THIS JET
SUPPORTING AN INTENSIFYING TROWAL THIS MORNING OVER IOWA AND
NORTHEAST MISSOURI. SUSPECT THAT THIS MORNING INTO THE EARLY
AFTERNOON AS THE DRY INTRUSION MOVES IN THAT THE PREDOMINANT PRECIP
TYPE WILL SHIFT TO DRIZZLE AND VERY LIGHT RAIN...THOUGH AS THE VORT
NEAR MCI MOVES EAST COULD SEE SOME SHOWERS REDEVELOPING IMMEDIATELY
IN ADVANCE OF THIS FEATURE. BY MIDDAY/EARLY AFTERNOON THE TROWAL
OVER IOWA/NORTHWEST MO WILL BEGIN TO TRANSLATE EAST INTO NORTHERN
ILLINOIS...BUT BY THAT POINT INSTABILITY WILL BE WEAKENING AND
BECOMING MORE FOCUSED TO OUR NORTH. ALSO...STRONG SYNOPTIC ASCENT
WILL ALSO BE SHIFTING NORTH INTO WI/MI AS THE MID LEVEL JET STREAK
PUNCH NORTH INTO THE UPPER GREAT LAKES. SUSPECT THAT THIS WILL LEAVE
OUR CWA WITH A GLANCING BLOW FROM THE DECAYING SOUTHERN FLANKS OF
WHAT WILL BE A VERY HEALTHY TROWEL THIS MORNING. COMPUTER MODELS AND
HPC GUIDANCE WOULD SUGGEST A SWATH OF 3 TO 5 INCHES OF SNOW ACROSS
OUR NORTHWEST CWA WHERE I PLACED THE ADVISORY...WHILE WHAT I`M
LOOKING AT IN OBSERVATIONAL DATA MAKE ME WONDER IF WE`LL BE ABLE TO
SQUEEZE OUT EVEN 2 INCHES. AS A COMPROMISE WILL GO WITH 2 TO 4
INCHES "POSSIBLE" WORDING AND PUT OUT AN ADVISORY TO BLEND WITH
NEIGHBORS AND ERR ON THE SIDE OF CAUTION...BUT DEFINITELY SEEING
SOME BUST POTENTIAL IN THIS FORECAST.
ACROSS THE REMAINDER OF THE CWA EXPECT DRIZZLY/SHOWERY WEATHER MUCH
OF THE DAY WITH A TRANSITION FROM RAIN TO SNOW TAKING PLACE FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. SUPPOSE THERE COULD BE UP TO
AN INCH OF ACCUMULATION FROM THE REMNANTS OF THE TROWAL BUT NOT
LOOKING TO BE A TERRIBLY BIG DEAL. IN FACT...THE FALLING TEMPS AND
BLUSTERY WINDS WILL PROBABLY BE THE BIGGER STORY FOR MOST.
DEEP TROUGH THEN ESTABLISHES ITSELF OVER THE GREAT LAKES AND
NORTHEAST FOR THE REMAINDER OF THE WEEK. FORECAST SOUNDINGS SHOW THE
PRESENCE OF A STOUT FRONTAL INVERSION WHICH OFTEN TRAPS
MOISTURE/STRATUS THIS TIME OF YEAR...PARTICULARLY WITH THE CYCLONIC
LOW LEVEL FLOW FORECAST TO BE IN PLACE THROUGH THE REST OF THE WORK
WEEK. GUIDANCE CONTINUE TO FORECAST H8 TEMPS DROPPING TO -20C OR A
BIT COLDER BY THURSDAY AFTERNOON...SO CERTAINLY LOOKS TO BE A VERY
FORMIDABLE SHOT OF ARCTIC AIR. HOWEVER...HAVE GENERALLY TRENDED
TEMPS TOWARD THE WARMEST AVAILABLE GUIDANCE TONIGHT AS STRONG WINDS
AND STRATUS ARE EXPECTED TO HELP KEEP TEMPS UP. AS SECONDARY SURGE
OF ARCTIC AIR ARRIVES THURSDAY PROBABLY WILL SEE VERY LITTLE
RECOVERY INTO TEMPS AND WITH CLOUDS LIKELY TO LINGER THURSDAY NIGHT
AGAIN WENT WITH THE WARMER SIDE OF GUIDANCE. THE EXPECTED LACK OF
SNOW COVER WOULD ALSO TEND TO SUPPORT NOT GOING AS COLD AS MOS
NUMBERS FOR THIS TIME PERIOD.
PRECIP WISE AFTER TODAY NOT ANTICIPATING ANY BIG PRECIP THREAT UNTIL
FRIDAY NIGHT. HOWEVER...THE PRESENCE OF A STRATUS DECK WITH TEMPS
FROM THE SFC TO 700MB PROGGED TO DROP INTO THE PRIME DENDRITIC
GROWTH RANGE SUGGESTS THAT IT WILL TAKE VERY LITTLE FORCING FOR THIS
DECK TO LEAK FLURRIES OR EVEN LIGHT SNOW. THE BEST CHANCE OF "FLAKY
STRATUS" LOOKS TO BE THURSDAY INTO THURSDAY NIGHT AS THAT SECONDARY
SURGE OF COLD AIR ARRIVES...BUT JUST ABOUT ANY WEAK IMPULSE PIVOTING
AROUND THE TROUGH COULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW OR
FLURRIES.
STRONGER CLIPPER IS STILL PROGGED TO ZIP SOUTHEAST INTO THE REGION
FRIDAY NIGHT INTO SATURDAY AND GIVEN THE COLD AIR MASS IN PLACE
COULD EASILY WRING OUT A SWATH OF A COUPLE/FEW INCHES OF SNOW.
GUIDANCE STILL SUGGESTS THAT THE BEST CHANCES OF THIS WOULD BE IN
OUR SOUTHERN CWA AND GIVEN A COUPLE DAYS OF CONSISTENCY IN THE
MODELS HAVE GONE ABOVE GUIDANCE POPS AND NUDGED UP TO LOW END
LIKELYS. OBVIOUSLY AS WE GET CLOSER TO THE EVENT THE TRACK COULD
NEED TO BE NUDGED NORTH OR SOUTH...BUT DOES LOOKS LIKE SOMEWHERE IN
THE NEIGHBORHOOD STANDS A DECENT SHOT OF SOME ACCUMULATING SNOW. A
MODERATING TREND STILL APPEARS TO BE IN THE OFFING LATER IN THE
WEEKEND INTO EARLY NEXT WEEK AS THE UPPER FLOW FLATTENS OUT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NW WINDS INCREASING THROUGH THE AFTN AND GUSTING TO 25-30 KT
BY LATE AFTN AND EVENING.
* AREAS OF RAIN/SNOW CHANGING TO ALL SNOW. VSBY BRIEFLY DOWN TO
1-3 MILES AT ORD THROUGH EARLY EVENING.
* CONDITIONS IMPROVING TO MVFR CIG/VSBY THIS EVE.
ALLSOPP
//DISCUSSION...UPDATED 20Z...
AREAS OF SNOW ARE MOVING ACROSS EASTERN IA AND NORTHERN
IL...MAINLY DPA...ORD NORTHWARD. LESS IMPACT AT MDW. VSBY AT TIMES
1-3 MILES BUT THEN BOUNCING UP TO VFR. EXPECT A DUSTING TO 1/2
INCH ACCUMULATION.
PREVIOUS DISCUSSION 18Z...
WEAK LOW PRESSURE OVER CHICAGO AT NOON...WILL MOVE NORTHEAST ACROSS
SOUTHERN LAKE MI THIS AFTERNOON. WINDS SHIFT NW IN THE WAKE OF THE
LOW...AND LIGHT RAIN AND DRIZZLE MIXES WITH AND CHANGES TO SNOW.
HOWEVER RADAR TRENDS SHOW THE BACK EDGE OF PRECIP LIFTING RAPIDLY
NORTHEAST ABOUT THE TIME PRECIP CHANGES FROM RAIN TO SNOW...SO NO
ACCUMULATION EXPECTED AT ORD OR MDW. IN FACT...VISIBILITY WILL
IMPROVE RAPIDLY THIS AFTERNOON AS PRECIP ENDS AND COLDER DRIER AIR
ARRIVES. IFR CIGS HAVE BEEN RUNNING AROUND 600 TO 800 FEET BUT
SHOULD GRADUALLY IMPROVE TO MVFR AROUND 1000-1500 FT DURING THE
AFTERNOON. CIGS SHOULD GRADUALLY LIFT TO AROUND 2000 FT OR BETTER
THIS EVENING.
AS CIGS AND VSBYS IMPROVE...NORTHWEST WINDS WILL BE PICKING UP
THROUGH THE AFTERNOON. STRONG ARCTIC HIGH PRESSURE BUILDING INTO
THE CENTRAL PLAINS WILL CREATE A TIGHT PRESSURE GRADIENT WHICH
WILL PERSIST INTO THURSDAY NIGHT. BY MID TO LATE THIS AFTERNOON
WINDS WILL BE 15-20 KT SUSTAINED WITH GUSTS 25-30 KT. WINDS MAY
DIMINISH SLIGHTLY LATE TONIGHT EARLY THU MORNING...BUT GUSTS WILL
PICK UP TO 25-30 AGAIN LATE MORNING AND AFTERNOON.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW TO MEDIUM CONFIDENCE IN CIG/VSBY TRENDS WITH SNOW. LOTS OF
VARIABILITY IN VSBY NEXT SEVERAL HOURS.
* MEDIUM-HIGH CONFIDENCE IN IMPROVING CIG/VSBY THIS EVENING.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR...THEN MVFR AND A CHANCE OF SNOW OVERNIGHT.
SATURDAY...MVFR BECOMING VFR.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR.
TRS
&&
.MARINE...
208 PM CST
ELONGATED AREA OF LOW PRESSURE STRETCHED FROM SOUTHERN LAKE MICHIGAN
INTO SOUTHERN QUEBEC THIS AFTERNOON...WITH LOW PRESSURE CENTER OVER
SOUTHWEST LOWER MICHIGAN EXPECTED TO DEEPEN AS IT LIFTS NORTHEAST
AWAY FROM LAKE MICHIGAN TONIGHT. THE COMBINATION OF TIGHTENING
SURFACE PRESSURE GRADIENT AND THE ADVECTION OF MUCH COLDER AIR
BEHIND THE LOW WILL PROVIDE FOR NORTH-NORTHWEST GALES ACROSS THE
LAKE TONIGHT. WINDS WILL GRADUALLY EASE BELOW GALE FORCE THURSDAY
MORNING...THOUGH WITH CANADIAN HIGH PRESSURE BUILDING SOUTHEAST
ACROSS THE PLAINS THE GRADIENT WILL REMAIN FAIRLY STOUT. THIS WILL
KEEP WINDS IN THE 20-30 KT RANGE THROUGH THURSDAY NIGHT AND EARLY
FRIDAY...THOUGH WITH A MORE-BACKED WEST-NORTHWEST DIRECTION.
GIVEN THE EXPECTED PROGRESSION OF WIND TRENDS...THE CURRENT GALE
WARNING FOR THE LAKE MICHIGAN OPEN WATERS APPEARS REASONABLE RUNNING
THROUGH 9 AM CST THURSDAY...THOUGH COULD PERHAPS SEE A FEW GALE
FORCE GUSTS LINGER ACROSS THE SOUTHEAST PART OF THE LAKE THROUGH
LATE THURSDAY MORNING. TIMING OF THE GALE WARNING FOR INDIANA
NEARSHORE ZONES ENDING AT 4 AM CST THURSDAY ALSO STILL APPEARS ON
TRACK. SMALL CRAFT ADVISORIES WILL LIKELY NEED TO BE CARRIED THROUGH
MUCH OF FRIDAY...PARTICULARLY FOR THE INDIANA NEARSHORE ZONES WHERE
WAVES WILL BE SLOWEST TO COME DOWN IN PERSISTENT WEST-NORTHWEST
FLOW.
WINDS SHOULD DECREASE MORE MARKEDLY ACROSS THE LAKE BY FRIDAY
AFTERNOON AS THE NORTHERN EXTENSION OF THE SURFACE HIGH PRESSURE
RIDGE AXIS MOVES ACROSS THE AREA. A WEAK CLIPPER-TYPE LOW PRESSURE
SYSTEM IS ANTICIPATED TO MOVE ACROSS THE MIDWEST SOUTH OF THE LAKES
SATURDAY WHICH MAY RESULT IN SOME FLUCTUATION IN WIND DIRECTION
DEPENDING ON DETAILS OF LOW TRACK...THOUGH WINDS SHOULD REMAIN LESS
THAN 20 KTS. A SECOND STRONGER LOW WILL PASS ACROSS THE NORTHERN
LAKES SATURDAY NIGHT...WHICH WILL RESULT IN ANOTHER FAIRLY SHORT
PERIOD OF STRONGER 30 KT NORTHWEST WINDS LATER SATURDAY NIGHT INTO
SUNDAY. WINDS WILL COME BACK DOWN AS HIGH PRESSURE RIDGING THEN
MOVES IN QUICKLY AGAIN SUNDAY NIGHT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008 UNTIL 4 PM
WEDNESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 4 AM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CST WED JAN 30 2013
.DISCUSSION...
944 AM CST
A WEAK SECONDARY SURFACE LOW IS MAKING ITS WAY THROUGH NORTHERN IL
THIS MORNING WITH ARCTIC AIR SLOWLY SPILLING INTO WESTERN IL.
FREEPORT IL HAS ALREADY TURNED OVER TO SNOW AND GETTING REPORTS
OF RAIN MIXING WITH SLEET FROM DIXON AND ROCKFORD. AS TEMPS FALL
TODAY EXPECTING RAIN TO QUICKLY CHANGE OVER TO SNOW WITH A BRIEF
PERIOD OF SLEET/ICE PELLETS POSSIBLE. NOT EXPECTING ANY
SIGNIFICANT IMPACTS FROM SLEET/ICE PELLETS.
FOR THE WINTER WEATHER ADVISORY FOR WINNEBAGO...OGLE...AND BOONE
COUNTIES...WILL KEEP IT GOING BUT THINKING THE BEST FORCING WILL
OCCUR WHEN TEMPS ARE ABOVE FREEZING. THE UPPER LEVEL JET STREAKS
LEFT EXIT REGION IS OVER NORTHERN IL WHILE THE SPC RAP AND OTHER
GUIDANCE INDICATE A BAND OF 850 MB FRONTOGENESIS EXTENDING FROM
SOUTHERN WI THROUGH MOLINE IL. NEGATIVE EPV LIES ABOVE THE
FRONTOGENESIS WHICH WOULD SUPPORT BANDS OF LOCALLY HEAVIER
SNOWFALL. HOWEVER...THE FRONTOGENESIS IS EXPECTED TO WEAKEN
SIGNIFICANTLY THROUGH THE EARLY AFTERNOON HOURS SO THINKING THE
HEAVIEST SNOW WILL FALL THROUGH 3PM AT THE LATEST ACROSS THE
ADVISORY AREA. GIVEN THAT RAIN IS JUST TURNING OVER TO SNOW
NOW...AGREE WITH THE PREVIOUS FORECAST THAT THE ADVISORY CRITERIA
WILL PROBABLY ONLY BE MET IN ISOLATED LOCATIONS. OVERALL EXPECTING
2-4 INCHES OF SNOW IN THE ADVISORY AREA WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IF A MESOSCALE BAND SETS UP OVER THE AREA.
AS TEMPS FALL THROUGH THE DAY RAIN WILL TURN OVER TO SNOW
THROUGHOUT THE DAY. ROUGH TIMINGS ARE ALL SNOW ACROSS THE ADVISORY
AREA BY NOON...NORTH OF I-55 BY 4-5 PM...CHICAGO BY 5-6 PM...AND
ALL SNOW ACROSS THE AREA BY 7-8PM. EXPECTING A WET SNOW AS IT
FIRST TURNS OVER THEN BECOMING A MORE AVERAGE SNOW LATE THIS
AFTERNOON/EVENING. ONCE AGAIN EXPECTING 2-4 INCHES IN THE
NORTHWEST CORNER OF THE CWA...1-2 INCHES NORTH OF A MENDOTA TO
WAUKEGAN LINE...AND LESS THAN AN INCH ELSEWHERE.
JEE
//PREV DISCUSSION...
353 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE POTENTIAL FOR SNOW
TODAY...CLOUD COVER AND ITS POTENTIAL IMPACTS ON TEMPS...AND CLIPPER
SYSTEM ARRIVING FRIDAY NIGHT INTO SATURDAY.
VERY TRICKY FORECAST TODAY AS COLDER AIR SPILLS INTO THE REGION AND
PORTIONS OF THE CWA POTENTIALLY GET CLIPPED BY TROWAL. HAVE OPTED TO
ISSUE A WINTER WX ADVISORY FOR MY NW 3 COUNTIES MOSTLY DUE TO MODEL
GUIDANCE AND TO MAKE A PRETTIER WATCH/WARNING/ADVISORY MAP BUT HAVE
SERIOUS DOUBTS ABOUT WHETHER IT WILL COME CLOSE TO VERIFYING BASED
ON CURRENT TRENDS IN OBSERVATIONAL DATA. WARM CONVEYOR BELT WITH
ITS MASSIVE STREAM OF RAIN CONTINUES TO SHIFT EASTWARD AND OUT OF
THE CWA EARLY THIS MORNING AND WOULD ANTICIPATE THIS TREND TO
CONTINUE AS WATER VAPOR IMAGERY SHOWS MASSIVE DEVELOPING MID LEVEL
DRY INTRUSION PUNCHING NORTHEAST INTO THE REGION. SURFACE ANALYSIS
HAS ANOTHER IN SEEMING CONGA LINE OF LOWS OVER MISSOURI STILL AT
09Z...AS THIS LOW TRANSLATES NORTHEAST INTO ILLINOIS EARLY THIS
MORNING IT WILL ACT TO SLOW THE INTRUSION OF COLD AIR AND LIKELY
DELAY THE RAIN/SNOW TRANSITION LINE FROM MAKING GOOD HEADWAY ACROSS
THE CWA UNTIL IT LIFTS OUT OF THE AREA TOWARD MIDDAY.
PROFILERS AND OBJECTIVE ANALYSIS HAVE A 120KT+ 500MB JET PUNCHING NE
INTO THE DRY INTRUSION WITH STRONG ASCENT TO THE LEFT OF THIS JET
SUPPORTING AN INTENSIFYING TROWAL THIS MORNING OVER IOWA AND
NORTHEAST MISSOURI. SUSPECT THAT THIS MORNING INTO THE EARLY
AFTERNOON AS THE DRY INTRUSION MOVES IN THAT THE PREDOMINANT PRECIP
TYPE WILL SHIFT TO DRIZZLE AND VERY LIGHT RAIN...THOUGH AS THE VORT
NEAR MCI MOVES EAST COULD SEE SOME SHOWERS REDEVELOPING IMMEDIATELY
IN ADVANCE OF THIS FEATURE. BY MIDDAY/EARLY AFTERNOON THE TROWAL
OVER IOWA/NORTHWEST MO WILL BEGIN TO TRANSLATE EAST INTO NORTHERN
ILLINOIS...BUT BY THAT POINT INSTABILITY WILL BE WEAKENING AND
BECOMING MORE FOCUSED TO OUR NORTH. ALSO...STRONG SYNOPTIC ASCENT
WILL ALSO BE SHIFTING NORTH INTO WI/MI AS THE MID LEVEL JET STREAK
PUNCH NORTH INTO THE UPPER GREAT LAKES. SUSPECT THAT THIS WILL LEAVE
OUR CWA WITH A GLANCING BLOW FROM THE DECAYING SOUTHERN FLANKS OF
WHAT WILL BE A VERY HEALTHY TROWEL THIS MORNING. COMPUTER MODELS AND
HPC GUIDANCE WOULD SUGGEST A SWATH OF 3 TO 5 INCHES OF SNOW ACROSS
OUR NORTHWEST CWA WHERE I PLACED THE ADVISORY...WHILE WHAT I`M
LOOKING AT IN OBSERVATIONAL DATA MAKE ME WONDER IF WE`LL BE ABLE TO
SQUEEZE OUT EVEN 2 INCHES. AS A COMPROMISE WILL GO WITH 2 TO 4
INCHES "POSSIBLE" WORDING AND PUT OUT AN ADVISORY TO BLEND WITH
NEIGHBORS AND ERR ON THE SIDE OF CAUTION...BUT DEFINITELY SEEING
SOME BUST POTENTIAL IN THIS FORECAST.
ACROSS THE REMAINDER OF THE CWA EXPECT DRIZZLY/SHOWERY WEATHER MUCH
OF THE DAY WITH A TRANSITION FROM RAIN TO SNOW TAKING PLACE FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. SUPPOSE THERE COULD BE UP TO
AN INCH OF ACCUMULATION FROM THE REMNANTS OF THE TROWAL BUT NOT
LOOKING TO BE A TERRIBLY BIG DEAL. IN FACT...THE FALLING TEMPS AND
BLUSTERY WINDS WILL PROBABLY BE THE BIGGER STORY FOR MOST.
DEEP TROUGH THEN ESTABLISHES ITSELF OVER THE GREAT LAKES AND
NORTHEAST FOR THE REMAINDER OF THE WEEK. FORECAST SOUNDINGS SHOW THE
PRESENCE OF A STOUT FRONTAL INVERSION WHICH OFTEN TRAPS
MOISTURE/STRATUS THIS TIME OF YEAR...PARTICULARLY WITH THE CYCLONIC
LOW LEVEL FLOW FORECAST TO BE IN PLACE THROUGH THE REST OF THE WORK
WEEK. GUIDANCE CONTINUE TO FORECAST H8 TEMPS DROPPING TO -20C OR A
BIT COLDER BY THURSDAY AFTERNOON...SO CERTAINLY LOOKS TO BE A VERY
FORMIDABLE SHOT OF ARCTIC AIR. HOWEVER...HAVE GENERALLY TRENDED
TEMPS TOWARD THE WARMEST AVAILABLE GUIDANCE TONIGHT AS STRONG WINDS
AND STRATUS ARE EXPECTED TO HELP KEEP TEMPS UP. AS SECONDARY SURGE
OF ARCTIC AIR ARRIVES THURSDAY PROBABLY WILL SEE VERY LITTLE
RECOVERY INTO TEMPS AND WITH CLOUDS LIKELY TO LINGER THURSDAY NIGHT
AGAIN WENT WITH THE WARMER SIDE OF GUIDANCE. THE EXPECTED LACK OF
SNOW COVER WOULD ALSO TEND TO SUPPORT NOT GOING AS COLD AS MOS
NUMBERS FOR THIS TIME PERIOD.
PRECIP WISE AFTER TODAY NOT ANTICIPATING ANY BIG PRECIP THREAT UNTIL
FRIDAY NIGHT. HOWEVER...THE PRESENCE OF A STRATUS DECK WITH TEMPS
FROM THE SFC TO 700MB PROGGED TO DROP INTO THE PRIME DENDRITIC
GROWTH RANGE SUGGESTS THAT IT WILL TAKE VERY LITTLE FORCING FOR THIS
DECK TO LEAK FLURRIES OR EVEN LIGHT SNOW. THE BEST CHANCE OF "FLAKY
STRATUS" LOOKS TO BE THURSDAY INTO THURSDAY NIGHT AS THAT SECONDARY
SURGE OF COLD AIR ARRIVES...BUT JUST ABOUT ANY WEAK IMPULSE PIVOTING
AROUND THE TROUGH COULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW OR
FLURRIES.
STRONGER CLIPPER IS STILL PROGGED TO ZIP SOUTHEAST INTO THE REGION
FRIDAY NIGHT INTO SATURDAY AND GIVEN THE COLD AIR MASS IN PLACE
COULD EASILY WRING OUT A SWATH OF A COUPLE/FEW INCHES OF SNOW.
GUIDANCE STILL SUGGESTS THAT THE BEST CHANCES OF THIS WOULD BE IN
OUR SOUTHERN CWA AND GIVEN A COUPLE DAYS OF CONSISTENCY IN THE
MODELS HAVE GONE ABOVE GUIDANCE POPS AND NUDGED UP TO LOW END
LIKELYS. OBVIOUSLY AS WE GET CLOSER TO THE EVENT THE TRACK COULD
NEED TO BE NUDGED NORTH OR SOUTH...BUT DOES LOOKS LIKE SOMEWHERE IN
THE NEIGHBORHOOD STANDS A DECENT SHOT OF SOME ACCUMULATING SNOW. A
MODERATING TREND STILL APPEARS TO BE IN THE OFFING LATER IN THE
WEEKEND INTO EARLY NEXT WEEK AS THE UPPER FLOW FLATTENS OUT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NW WINDS INCREASING THROUGH THE AFTN AND GUSTING TO 25-30 KT
BY LATE AFTN AND EVENING.
* AREAS OF RAIN/SNOW CHANGING TO ALL SNOW. VSBY BRIEFLY DOWN TO
1-3 MILES AT ORD THROUGH EARLY EVENING.
* CONDITIONS IMPROVING TO MVFR CIG/VSBY THIS EVE.
ALLSOPP
//DISCUSSION...UPDATED 20Z...
AREAS OF SNOW ARE MOVING ACROSS EASTERN IA AND NORTHERN
IL...MAINLY DPA...ORD NORTHWARD. LESS IMPACT AT MDW. VSBY AT TIMES
1-3 MILES BUT THEN BOUNCING UP TO VFR. EXPECT A DUSTING TO 1/2
INCH ACCUMULATION.
PREVIOUS DISCUSSION 18Z...
WEAK LOW PRESSURE OVER CHICAGO AT NOON...WILL MOVE NORTHEAST ACROSS
SOUTHERN LAKE MI THIS AFTERNOON. WINDS SHIFT NW IN THE WAKE OF THE
LOW...AND LIGHT RAIN AND DRIZZLE MIXES WITH AND CHANGES TO SNOW.
HOWEVER RADAR TRENDS SHOW THE BACK EDGE OF PRECIP LIFTING RAPIDLY
NORTHEAST ABOUT THE TIME PRECIP CHANGES FROM RAIN TO SNOW...SO NO
ACCUMULATION EXPECTED AT ORD OR MDW. IN FACT...VISIBILITY WILL
IMPROVE RAPIDLY THIS AFTERNOON AS PRECIP ENDS AND COLDER DRIER AIR
ARRIVES. IFR CIGS HAVE BEEN RUNNING AROUND 600 TO 800 FEET BUT
SHOULD GRADUALLY IMPROVE TO MVFR AROUND 1000-1500 FT DURING THE
AFTERNOON. CIGS SHOULD GRADUALLY LIFT TO AROUND 2000 FT OR BETTER
THIS EVENING.
AS CIGS AND VSBYS IMPROVE...NORTHWEST WINDS WILL BE PICKING UP
THROUGH THE AFTERNOON. STRONG ARCTIC HIGH PRESSURE BUILDING INTO
THE CENTRAL PLAINS WILL CREATE A TIGHT PRESSURE GRADIENT WHICH
WILL PERSIST INTO THURSDAY NIGHT. BY MID TO LATE THIS AFTERNOON
WINDS WILL BE 15-20 KT SUSTAINED WITH GUSTS 25-30 KT. WINDS MAY
DIMINISH SLIGHTLY LATE TONIGHT EARLY THU MORNING...BUT GUSTS WILL
PICK UP TO 25-30 AGAIN LATE MORNING AND AFTERNOON.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW TO MEDIUM CONFIDENCE IN CIG/VSBY TRENDS WITH SNOW. LOTS OF
VARIABILITY IN VSBY NEXT SEVERAL HOURS.
* MEDIUM-HIGH CONFIDENCE IN IMPROVING CIG/VSBY THIS EVENING.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR...THEN MVFR AND A CHANCE OF SNOW OVERNIGHT.
SATURDAY...MVFR BECOMING VFR.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR.
TRS
&&
.MARINE...
345 AM CST
RAPIDLY CHANGING WINDS ARE ONGOING ACROSS THE LAKE AS A TROUGH OF
LOW PRESSURE SITUATED ACROSS THE REGION CONTINUES TO SLOWLY WORK
ITS WAY TO THE NORTHEAST TODAY. AS THIS OCCURS...THE PRESSURE
GRADIENT WILL BECOME MORE ORGANIZED WITH STRONG NORTHERLY WINDS
PICKING UP THROUGHOUT THE DAY. EXPECT NORTHERLY WINDS TO 30 KT
THIS MORNING TO CONTINUE INCREASING TO GALES TODAY AND THIS
EVENING...WITH NOW A PORTION OF THE NEARSHORE WATERS OBSERVING
THESE NORTHERLY GALES. HAVE MAINTAINED A MENTION OF GALES TO 40 KT
FOR A PERIOD LATER TODAY...AS WINDS TURN MORE TOWARDS THE
NORTHWEST AND WEST LATER TONIGHT. AS THIS OCCURS...EXPECT WINDS TO
ALSO DIMINISH TO 30 KT THURSDAY MORNING BUT WITH THESE WESTERLY
WINDS TO 30 KT CONTINUING TO AT LEAST FRIDAY MORNING. ALTHOUGH NOT
LIKELY AT THIS TIME...THERE DOES APPEAR TO BE A BRIEF WINDOW OF
SOME WEST/NORTHWEST GALES DURING THE OVERNIGHT HOURS THURSDAY
NIGHT. WILL NEED TO CONTINUE TO MONITOR THIS GALE POTENTIAL
THURSDAY NIGHT...ALSO AS STRONGER WESTERLY WINDS IN THE NEARSHORE
PERSIST AT LEAST THROUGH LATE THURSDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008 UNTIL 4 PM
WEDNESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 4 AM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1155 AM CST WED JAN 30 2013
.DISCUSSION...
944 AM CST
A WEAK SECONDARY SURFACE LOW IS MAKING ITS WAY THROUGH NORTHERN IL
THIS MORNING WITH ARCTIC AIR SLOWLY SPILLING INTO WESTERN IL.
FREEPORT IL HAS ALREADY TURNED OVER TO SNOW AND GETTING REPORTS
OF RAIN MIXING WITH SLEET FROM DIXON AND ROCKFORD. AS TEMPS FALL
TODAY EXPECTING RAIN TO QUICKLY CHANGE OVER TO SNOW WITH A BRIEF
PERIOD OF SLEET/ICE PELLETS POSSIBLE. NOT EXPECTING ANY
SIGNIFICANT IMPACTS FROM SLEET/ICE PELLETS.
FOR THE WINTER WEATHER ADVISORY FOR WINNEBAGO...OGLE...AND BOONE
COUNTIES...WILL KEEP IT GOING BUT THINKING THE BEST FORCING WILL
OCCUR WHEN TEMPS ARE ABOVE FREEZING. THE UPPER LEVEL JET STREAKS
LEFT EXIT REGION IS OVER NORTHERN IL WHILE THE SPC RAP AND OTHER
GUIDANCE INDICATE A BAND OF 850 MB FRONTOGENESIS EXTENDING FROM
SOUTHERN WI THROUGH MOLINE IL. NEGATIVE EPV LIES ABOVE THE
FRONTOGENESIS WHICH WOULD SUPPORT BANDS OF LOCALLY HEAVIER
SNOWFALL. HOWEVER...THE FRONTOGENESIS IS EXPECTED TO WEAKEN
SIGNIFICANTLY THROUGH THE EARLY AFTERNOON HOURS SO THINKING THE
HEAVIEST SNOW WILL FALL THROUGH 3PM AT THE LATEST ACROSS THE
ADVISORY AREA. GIVEN THAT RAIN IS JUST TURNING OVER TO SNOW
NOW...AGREE WITH THE PREVIOUS FORECAST THAT THE ADVISORY CRITERIA
WILL PROBABLY ONLY BE MET IN ISOLATED LOCATIONS. OVERALL EXPECTING
2-4 INCHES OF SNOW IN THE ADVISORY AREA WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IF A MESOSCALE BAND SETS UP OVER THE AREA.
AS TEMPS FALL THROUGH THE DAY RAIN WILL TURN OVER TO SNOW
THROUGHOUT THE DAY. ROUGH TIMINGS ARE ALL SNOW ACROSS THE ADVISORY
AREA BY NOON...NORTH OF I-55 BY 4-5 PM...CHICAGO BY 5-6 PM...AND
ALL SNOW ACROSS THE AREA BY 7-8PM. EXPECTING A WET SNOW AS IT
FIRST TURNS OVER THEN BECOMING A MORE AVERAGE SNOW LATE THIS
AFTERNOON/EVENING. ONCE AGAIN EXPECTING 2-4 INCHES IN THE
NORTHWEST CORNER OF THE CWA...1-2 INCHES NORTH OF A MENDOTA TO
WAUKEGAN LINE...AND LESS THAN AN INCH ELSEWHERE.
JEE
//PREV DISCUSSION...
353 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE POTENTIAL FOR SNOW
TODAY...CLOUD COVER AND ITS POTENTIAL IMPACTS ON TEMPS...AND CLIPPER
SYSTEM ARRIVING FRIDAY NIGHT INTO SATURDAY.
VERY TRICKY FORECAST TODAY AS COLDER AIR SPILLS INTO THE REGION AND
PORTIONS OF THE CWA POTENTIALLY GET CLIPPED BY TROWAL. HAVE OPTED TO
ISSUE A WINTER WX ADVISORY FOR MY NW 3 COUNTIES MOSTLY DUE TO MODEL
GUIDANCE AND TO MAKE A PRETTIER WATCH/WARNING/ADVISORY MAP BUT HAVE
SERIOUS DOUBTS ABOUT WHETHER IT WILL COME CLOSE TO VERIFYING BASED
ON CURRENT TRENDS IN OBSERVATIONAL DATA. WARM CONVEYOR BELT WITH
ITS MASSIVE STREAM OF RAIN CONTINUES TO SHIFT EASTWARD AND OUT OF
THE CWA EARLY THIS MORNING AND WOULD ANTICIPATE THIS TREND TO
CONTINUE AS WATER VAPOR IMAGERY SHOWS MASSIVE DEVELOPING MID LEVEL
DRY INTRUSION PUNCHING NORTHEAST INTO THE REGION. SURFACE ANALYSIS
HAS ANOTHER IN SEEMING CONGA LINE OF LOWS OVER MISSOURI STILL AT
09Z...AS THIS LOW TRANSLATES NORTHEAST INTO ILLINOIS EARLY THIS
MORNING IT WILL ACT TO SLOW THE INTRUSION OF COLD AIR AND LIKELY
DELAY THE RAIN/SNOW TRANSITION LINE FROM MAKING GOOD HEADWAY ACROSS
THE CWA UNTIL IT LIFTS OUT OF THE AREA TOWARD MIDDAY.
PROFILERS AND OBJECTIVE ANALYSIS HAVE A 120KT+ 500MB JET PUNCHING NE
INTO THE DRY INTRUSION WITH STRONG ASCENT TO THE LEFT OF THIS JET
SUPPORTING AN INTENSIFYING TROWAL THIS MORNING OVER IOWA AND
NORTHEAST MISSOURI. SUSPECT THAT THIS MORNING INTO THE EARLY
AFTERNOON AS THE DRY INTRUSION MOVES IN THAT THE PREDOMINANT PRECIP
TYPE WILL SHIFT TO DRIZZLE AND VERY LIGHT RAIN...THOUGH AS THE VORT
NEAR MCI MOVES EAST COULD SEE SOME SHOWERS REDEVELOPING IMMEDIATELY
IN ADVANCE OF THIS FEATURE. BY MIDDAY/EARLY AFTERNOON THE TROWAL
OVER IOWA/NORTHWEST MO WILL BEGIN TO TRANSLATE EAST INTO NORTHERN
ILLINOIS...BUT BY THAT POINT INSTABILITY WILL BE WEAKENING AND
BECOMING MORE FOCUSED TO OUR NORTH. ALSO...STRONG SYNOPTIC ASCENT
WILL ALSO BE SHIFTING NORTH INTO WI/MI AS THE MID LEVEL JET STREAK
PUNCH NORTH INTO THE UPPER GREAT LAKES. SUSPECT THAT THIS WILL LEAVE
OUR CWA WITH A GLANCING BLOW FROM THE DECAYING SOUTHERN FLANKS OF
WHAT WILL BE A VERY HEALTHY TROWEL THIS MORNING. COMPUTER MODELS AND
HPC GUIDANCE WOULD SUGGEST A SWATH OF 3 TO 5 INCHES OF SNOW ACROSS
OUR NORTHWEST CWA WHERE I PLACED THE ADVISORY...WHILE WHAT I`M
LOOKING AT IN OBSERVATIONAL DATA MAKE ME WONDER IF WE`LL BE ABLE TO
SQUEEZE OUT EVEN 2 INCHES. AS A COMPROMISE WILL GO WITH 2 TO 4
INCHES "POSSIBLE" WORDING AND PUT OUT AN ADVISORY TO BLEND WITH
NEIGHBORS AND ERR ON THE SIDE OF CAUTION...BUT DEFINITELY SEEING
SOME BUST POTENTIAL IN THIS FORECAST.
ACROSS THE REMAINDER OF THE CWA EXPECT DRIZZLY/SHOWERY WEATHER MUCH
OF THE DAY WITH A TRANSITION FROM RAIN TO SNOW TAKING PLACE FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. SUPPOSE THERE COULD BE UP TO
AN INCH OF ACCUMULATION FROM THE REMNANTS OF THE TROWAL BUT NOT
LOOKING TO BE A TERRIBLY BIG DEAL. IN FACT...THE FALLING TEMPS AND
BLUSTERY WINDS WILL PROBABLY BE THE BIGGER STORY FOR MOST.
DEEP TROUGH THEN ESTABLISHES ITSELF OVER THE GREAT LAKES AND
NORTHEAST FOR THE REMAINDER OF THE WEEK. FORECAST SOUNDINGS SHOW THE
PRESENCE OF A STOUT FRONTAL INVERSION WHICH OFTEN TRAPS
MOISTURE/STRATUS THIS TIME OF YEAR...PARTICULARLY WITH THE CYCLONIC
LOW LEVEL FLOW FORECAST TO BE IN PLACE THROUGH THE REST OF THE WORK
WEEK. GUIDANCE CONTINUE TO FORECAST H8 TEMPS DROPPING TO -20C OR A
BIT COLDER BY THURSDAY AFTERNOON...SO CERTAINLY LOOKS TO BE A VERY
FORMIDABLE SHOT OF ARCTIC AIR. HOWEVER...HAVE GENERALLY TRENDED
TEMPS TOWARD THE WARMEST AVAILABLE GUIDANCE TONIGHT AS STRONG WINDS
AND STRATUS ARE EXPECTED TO HELP KEEP TEMPS UP. AS SECONDARY SURGE
OF ARCTIC AIR ARRIVES THURSDAY PROBABLY WILL SEE VERY LITTLE
RECOVERY INTO TEMPS AND WITH CLOUDS LIKELY TO LINGER THURSDAY NIGHT
AGAIN WENT WITH THE WARMER SIDE OF GUIDANCE. THE EXPECTED LACK OF
SNOW COVER WOULD ALSO TEND TO SUPPORT NOT GOING AS COLD AS MOS
NUMBERS FOR THIS TIME PERIOD.
PRECIP WISE AFTER TODAY NOT ANTICIPATING ANY BIG PRECIP THREAT UNTIL
FRIDAY NIGHT. HOWEVER...THE PRESENCE OF A STRATUS DECK WITH TEMPS
FROM THE SFC TO 700MB PROGGED TO DROP INTO THE PRIME DENDRITIC
GROWTH RANGE SUGGESTS THAT IT WILL TAKE VERY LITTLE FORCING FOR THIS
DECK TO LEAK FLURRIES OR EVEN LIGHT SNOW. THE BEST CHANCE OF "FLAKY
STRATUS" LOOKS TO BE THURSDAY INTO THURSDAY NIGHT AS THAT SECONDARY
SURGE OF COLD AIR ARRIVES...BUT JUST ABOUT ANY WEAK IMPULSE PIVOTING
AROUND THE TROUGH COULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW OR
FLURRIES.
STRONGER CLIPPER IS STILL PROGGED TO ZIP SOUTHEAST INTO THE REGION
FRIDAY NIGHT INTO SATURDAY AND GIVEN THE COLD AIR MASS IN PLACE
COULD EASILY WRING OUT A SWATH OF A COUPLE/FEW INCHES OF SNOW.
GUIDANCE STILL SUGGESTS THAT THE BEST CHANCES OF THIS WOULD BE IN
OUR SOUTHERN CWA AND GIVEN A COUPLE DAYS OF CONSISTENCY IN THE
MODELS HAVE GONE ABOVE GUIDANCE POPS AND NUDGED UP TO LOW END
LIKELYS. OBVIOUSLY AS WE GET CLOSER TO THE EVENT THE TRACK COULD
NEED TO BE NUDGED NORTH OR SOUTH...BUT DOES LOOKS LIKE SOMEWHERE IN
THE NEIGHBORHOOD STANDS A DECENT SHOT OF SOME ACCUMULATING SNOW. A
MODERATING TREND STILL APPEARS TO BE IN THE OFFING LATER IN THE
WEEKEND INTO EARLY NEXT WEEK AS THE UPPER FLOW FLATTENS OUT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WIND SHIFTING NW AT ORD AROUND 18Z AND MDW AROUND 19Z.
* IFR VSBY INCREASING RAPIDLY TO VFR AS MAIN AREA OF PRECIP ENDS
EARLY AFTN.
* LIGHT RAIN MAY MIX WITH SNOW BRIEFLY EARLY AFTN BEFORE PRECIP
ENDS.
* IFR CIG GRADUALLY IMPROVING TO MVFR BY EVENING.
* NW WINDS INCREASING THROUGH THE AFTN AND GUSTING TO NEAR 30 KT
LATE AFTN AND OVERNIGHT.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
WEAK LOW PRESSURE OVER CHICAGO AT NOON...WILL MOVE NORTHEAST ACROSS
SOUTHERN LAKE MI THIS AFTERNOON. WINDS SHIFT NW IN THE WAKE OF THE
LOW...AND LIGHT RAIN AND DRIZZLE MIXES WITH AND CHANGES TO SNOW.
HOWEVER RADAR TRENDS SHOW THE BACK EDGE OF PRECIP LIFTING RAPIDLY
NORTHEAST ABOUT THE TIME PRECIP CHANGES FROM RAIN TO SNOW...SO NO
ACCUMULATION EXPECTED AT ORD OR MDW. IN FACT...VISIBILITY WILL
IMPROVE RAPIDLY THIS AFTERNOON AS PRECIP ENDS AND COLDER DRIER AIR
ARRIVES. IFR CIGS HAVE BEEN RUNNING AROUND 600 TO 800 FEET BUT
SHOULD GRADUALLY IMPROVE TO MVFR AROUND 1000-1500 FT DURING THE
AFTERNOON. CIGS SHOULD GRADUALLY LIFT TO AROUND 2000 FT OR BETTER
THIS EVENING.
AS CIGS AND VSBYS IMPROVE...NORTHWEST WINDS WILL BE PICKING UP
THROUGH THE AFTERNOON. STRONG ARCTIC HIGH PRESSURE BUILDING INTO
THE CENTRAL PLAINS WILL CREATE A TIGHT PRESSURE GRADIENT WHICH
WILL PERSIST INTO THURSDAY NIGHT. BY MID TO LATE THIS AFTERNOON
WINDS WILL BE 15-20 KT SUSTAINED WITH GUSTS 25-30 KT. WINDS MAY
DIMINISH SLIGHTLY LATE TONIGHT EARLY THU MORNING...BUT GUSTS WILL
PICK UP TO 25-30 AGAIN LATE MORNING AND AFTERNOON.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN VISIBILITY AND PRECIP TRENDS.
* MEDIUM-HIGH CONFIDENCE IN CIG TREND.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR...THEN MVFR AND A CHANCE OF SNOW OVERNIGHT.
SATURDAY...MVFR BECOMING VFR.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR.
TRS
&&
.MARINE...
345 AM CST
RAPIDLY CHANGING WINDS ARE ONGOING ACROSS THE LAKE AS A TROUGH OF
LOW PRESSURE SITUATED ACROSS THE REGION CONTINUES TO SLOWLY WORK
ITS WAY TO THE NORTHEAST TODAY. AS THIS OCCURS...THE PRESSURE
GRADIENT WILL BECOME MORE ORGANIZED WITH STRONG NORTHERLY WINDS
PICKING UP THROUGHOUT THE DAY. EXPECT NORTHERLY WINDS TO 30 KT
THIS MORNING TO CONTINUE INCREASING TO GALES TODAY AND THIS
EVENING...WITH NOW A PORTION OF THE NEARSHORE WATERS OBSERVING
THESE NORTHERLY GALES. HAVE MAINTAINED A MENTION OF GALES TO 40 KT
FOR A PERIOD LATER TODAY...AS WINDS TURN MORE TOWARDS THE
NORTHWEST AND WEST LATER TONIGHT. AS THIS OCCURS...EXPECT WINDS TO
ALSO DIMINISH TO 30 KT THURSDAY MORNING BUT WITH THESE WESTERLY
WINDS TO 30 KT CONTINUING TO AT LEAST FRIDAY MORNING. ALTHOUGH NOT
LIKELY AT THIS TIME...THERE DOES APPEAR TO BE A BRIEF WINDOW OF
SOME WEST/NORTHWEST GALES DURING THE OVERNIGHT HOURS THURSDAY
NIGHT. WILL NEED TO CONTINUE TO MONITOR THIS GALE POTENTIAL
THURSDAY NIGHT...ALSO AS STRONGER WESTERLY WINDS IN THE NEARSHORE
PERSIST AT LEAST THROUGH LATE THURSDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008 UNTIL 4 PM
WEDNESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 AM CST WED JAN 30 2013
.DISCUSSION...
944 AM CST
A WEAK SECONDARY SURFACE LOW IS MAKING ITS WAY THROUGH NORTHERN IL
THIS MORNING WITH ARCTIC AIR SLOWLY SPILLING INTO WESTERN IL.
FREEPORT IL HAS ALREADY TURNED OVER TO SNOW AND GETTING REPORTS
OF RAIN MIXING WITH SLEET FROM DIXON AND ROCKFORD. AS TEMPS FALL
TODAY EXPECTING RAIN TO QUICKLY CHANGE OVER TO SNOW WITH A BRIEF
PERIOD OF SLEET/ICE PELLETS POSSIBLE. NOT EXPECTING ANY
SIGNIFICANT IMPACTS FROM SLEET/ICE PELLETS.
FOR THE WINTER WEATHER ADVISORY FOR WINNEBAGO...OGLE...AND BOONE
COUNTIES...WILL KEEP IT GOING BUT THINKING THE BEST FORCING WILL
OCCUR WHEN TEMPS ARE ABOVE FREEZING. THE UPPER LEVEL JET STREAKS
LEFT EXIT REGION IS OVER NORTHERN IL WHILE THE SPC RAP AND OTHER
GUIDANCE INDICATE A BAND OF 850 MB FRONTOGENESIS EXTENDING FROM
SOUTHERN WI THROUGH MOLINE IL. NEGATIVE EPV LIES ABOVE THE
FRONTOGENESIS WHICH WOULD SUPPORT BANDS OF LOCALLY HEAVIER
SNOWFALL. HOWEVER...THE FRONTOGENESIS IS EXPECTED TO WEAKEN
SIGNIFICANTLY THROUGH THE EARLY AFTERNOON HOURS SO THINKING THE
HEAVIEST SNOW WILL FALL THROUGH 3PM AT THE LATEST ACROSS THE
ADVISORY AREA. GIVEN THAT RAIN IS JUST TURNING OVER TO SNOW
NOW...AGREE WITH THE PREVIOUS FORECAST THAT THE ADVISORY CRITERIA
WILL PROBABLY ONLY BE MET IN ISOLATED LOCATIONS. OVERALL EXPECTING
2-4 INCHES OF SNOW IN THE ADVISORY AREA WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IF A MESOSCALE BAND SETS UP OVER THE AREA.
AS TEMPS FALL THROUGH THE DAY RAIN WILL TURN OVER TO SNOW
THROUGHOUT THE DAY. ROUGH TIMINGS ARE ALL SNOW ACROSS THE ADVISORY
AREA BY NOON...NORTH OF I-55 BY 4-5 PM...CHICAGO BY 5-6 PM...AND
ALL SNOW ACROSS THE AREA BY 7-8PM. EXPECTING A WET SNOW AS IT
FIRST TURNS OVER THEN BECOMING A MORE AVERAGE SNOW LATE THIS
AFTERNOON/EVENING. ONCE AGAIN EXPECTING 2-4 INCHES IN THE
NORTHWEST CORNER OF THE CWA...1-2 INCHES NORTH OF A MENDOTA TO
WAUKEGAN LINE...AND LESS THAN AN INCH ELSEWHERE.
JEE
//PREV DISCUSSION...
353 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE POTENTIAL FOR SNOW
TODAY...CLOUD COVER AND ITS POTENTIAL IMPACTS ON TEMPS...AND CLIPPER
SYSTEM ARRIVING FRIDAY NIGHT INTO SATURDAY.
VERY TRICKY FORECAST TODAY AS COLDER AIR SPILLS INTO THE REGION AND
PORTIONS OF THE CWA POTENTIALLY GET CLIPPED BY TROWAL. HAVE OPTED TO
ISSUE A WINTER WX ADVISORY FOR MY NW 3 COUNTIES MOSTLY DUE TO MODEL
GUIDANCE AND TO MAKE A PRETTIER WATCH/WARNING/ADVISORY MAP BUT HAVE
SERIOUS DOUBTS ABOUT WHETHER IT WILL COME CLOSE TO VERIFYING BASED
ON CURRENT TRENDS IN OBSERVATIONAL DATA. WARM CONVEYOR BELT WITH
ITS MASSIVE STREAM OF RAIN CONTINUES TO SHIFT EASTWARD AND OUT OF
THE CWA EARLY THIS MORNING AND WOULD ANTICIPATE THIS TREND TO
CONTINUE AS WATER VAPOR IMAGERY SHOWS MASSIVE DEVELOPING MID LEVEL
DRY INTRUSION PUNCHING NORTHEAST INTO THE REGION. SURFACE ANALYSIS
HAS ANOTHER IN SEEMING CONGA LINE OF LOWS OVER MISSOURI STILL AT
09Z...AS THIS LOW TRANSLATES NORTHEAST INTO ILLINOIS EARLY THIS
MORNING IT WILL ACT TO SLOW THE INTRUSION OF COLD AIR AND LIKELY
DELAY THE RAIN/SNOW TRANSITION LINE FROM MAKING GOOD HEADWAY ACROSS
THE CWA UNTIL IT LIFTS OUT OF THE AREA TOWARD MIDDAY.
PROFILERS AND OBJECTIVE ANALYSIS HAVE A 120KT+ 500MB JET PUNCHING NE
INTO THE DRY INTRUSION WITH STRONG ASCENT TO THE LEFT OF THIS JET
SUPPORTING AN INTENSIFYING TROWAL THIS MORNING OVER IOWA AND
NORTHEAST MISSOURI. SUSPECT THAT THIS MORNING INTO THE EARLY
AFTERNOON AS THE DRY INTRUSION MOVES IN THAT THE PREDOMINANT PRECIP
TYPE WILL SHIFT TO DRIZZLE AND VERY LIGHT RAIN...THOUGH AS THE VORT
NEAR MCI MOVES EAST COULD SEE SOME SHOWERS REDEVELOPING IMMEDIATELY
IN ADVANCE OF THIS FEATURE. BY MIDDAY/EARLY AFTERNOON THE TROWAL
OVER IOWA/NORTHWEST MO WILL BEGIN TO TRANSLATE EAST INTO NORTHERN
ILLINOIS...BUT BY THAT POINT INSTABILITY WILL BE WEAKENING AND
BECOMING MORE FOCUSED TO OUR NORTH. ALSO...STRONG SYNOPTIC ASCENT
WILL ALSO BE SHIFTING NORTH INTO WI/MI AS THE MID LEVEL JET STREAK
PUNCH NORTH INTO THE UPPER GREAT LAKES. SUSPECT THAT THIS WILL LEAVE
OUR CWA WITH A GLANCING BLOW FROM THE DECAYING SOUTHERN FLANKS OF
WHAT WILL BE A VERY HEALTHY TROWEL THIS MORNING. COMPUTER MODELS AND
HPC GUIDANCE WOULD SUGGEST A SWATH OF 3 TO 5 INCHES OF SNOW ACROSS
OUR NORTHWEST CWA WHERE I PLACED THE ADVISORY...WHILE WHAT I`M
LOOKING AT IN OBSERVATIONAL DATA MAKE ME WONDER IF WE`LL BE ABLE TO
SQUEEZE OUT EVEN 2 INCHES. AS A COMPROMISE WILL GO WITH 2 TO 4
INCHES "POSSIBLE" WORDING AND PUT OUT AN ADVISORY TO BLEND WITH
NEIGHBORS AND ERR ON THE SIDE OF CAUTION...BUT DEFINITELY SEEING
SOME BUST POTENTIAL IN THIS FORECAST.
ACROSS THE REMAINDER OF THE CWA EXPECT DRIZZLY/SHOWERY WEATHER MUCH
OF THE DAY WITH A TRANSITION FROM RAIN TO SNOW TAKING PLACE FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. SUPPOSE THERE COULD BE UP TO
AN INCH OF ACCUMULATION FROM THE REMNANTS OF THE TROWAL BUT NOT
LOOKING TO BE A TERRIBLY BIG DEAL. IN FACT...THE FALLING TEMPS AND
BLUSTERY WINDS WILL PROBABLY BE THE BIGGER STORY FOR MOST.
DEEP TROUGH THEN ESTABLISHES ITSELF OVER THE GREAT LAKES AND
NORTHEAST FOR THE REMAINDER OF THE WEEK. FORECAST SOUNDINGS SHOW THE
PRESENCE OF A STOUT FRONTAL INVERSION WHICH OFTEN TRAPS
MOISTURE/STRATUS THIS TIME OF YEAR...PARTICULARLY WITH THE CYCLONIC
LOW LEVEL FLOW FORECAST TO BE IN PLACE THROUGH THE REST OF THE WORK
WEEK. GUIDANCE CONTINUE TO FORECAST H8 TEMPS DROPPING TO -20C OR A
BIT COLDER BY THURSDAY AFTERNOON...SO CERTAINLY LOOKS TO BE A VERY
FORMIDABLE SHOT OF ARCTIC AIR. HOWEVER...HAVE GENERALLY TRENDED
TEMPS TOWARD THE WARMEST AVAILABLE GUIDANCE TONIGHT AS STRONG WINDS
AND STRATUS ARE EXPECTED TO HELP KEEP TEMPS UP. AS SECONDARY SURGE
OF ARCTIC AIR ARRIVES THURSDAY PROBABLY WILL SEE VERY LITTLE
RECOVERY INTO TEMPS AND WITH CLOUDS LIKELY TO LINGER THURSDAY NIGHT
AGAIN WENT WITH THE WARMER SIDE OF GUIDANCE. THE EXPECTED LACK OF
SNOW COVER WOULD ALSO TEND TO SUPPORT NOT GOING AS COLD AS MOS
NUMBERS FOR THIS TIME PERIOD.
PRECIP WISE AFTER TODAY NOT ANTICIPATING ANY BIG PRECIP THREAT UNTIL
FRIDAY NIGHT. HOWEVER...THE PRESENCE OF A STRATUS DECK WITH TEMPS
FROM THE SFC TO 700MB PROGGED TO DROP INTO THE PRIME DENDRITIC
GROWTH RANGE SUGGESTS THAT IT WILL TAKE VERY LITTLE FORCING FOR THIS
DECK TO LEAK FLURRIES OR EVEN LIGHT SNOW. THE BEST CHANCE OF "FLAKY
STRATUS" LOOKS TO BE THURSDAY INTO THURSDAY NIGHT AS THAT SECONDARY
SURGE OF COLD AIR ARRIVES...BUT JUST ABOUT ANY WEAK IMPULSE PIVOTING
AROUND THE TROUGH COULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW OR
FLURRIES.
STRONGER CLIPPER IS STILL PROGGED TO ZIP SOUTHEAST INTO THE REGION
FRIDAY NIGHT INTO SATURDAY AND GIVEN THE COLD AIR MASS IN PLACE
COULD EASILY WRING OUT A SWATH OF A COUPLE/FEW INCHES OF SNOW.
GUIDANCE STILL SUGGESTS THAT THE BEST CHANCES OF THIS WOULD BE IN
OUR SOUTHERN CWA AND GIVEN A COUPLE DAYS OF CONSISTENCY IN THE
MODELS HAVE GONE ABOVE GUIDANCE POPS AND NUDGED UP TO LOW END
LIKELYS. OBVIOUSLY AS WE GET CLOSER TO THE EVENT THE TRACK COULD
NEED TO BE NUDGED NORTH OR SOUTH...BUT DOES LOOKS LIKE SOMEWHERE IN
THE NEIGHBORHOOD STANDS A DECENT SHOT OF SOME ACCUMULATING SNOW. A
MODERATING TREND STILL APPEARS TO BE IN THE OFFING LATER IN THE
WEEKEND INTO EARLY NEXT WEEK AS THE UPPER FLOW FLATTENS OUT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* ENE WINDS LESS THAN 10 KT SHIFTING TO NW AROUND 18Z AT ORD AND
19Z MDW.
* NW WINDS INCREASING THROUGH THE AFTN WITH GUSTS NEAR 30 KT LATE
AFTN AND EVENING.
* IFR CIG/VSBY IN RAIN DRIZZLE...CHANGING TO SNOW MID AFTN AND
ENDING LATE AFTN. LITTLE OR NO ACCUMULATION.
* CIG/VSBY IMPROVING TO MVFR BY EVENING.
ALLSOPP
//DISCUSSION...UPDATED 14Z...
WEAK LOW PRESSURE OVER CENTRAL IL WILL MOVE OVER CHICAGO AROUND
18Z. THIS WILL GIVE ORD AND DPA NE WINDS THIS MORNING. MDW AND GYY
MAY GO LIGHT AND VARIABLE AND GYY MAY EVEN GO LIGHT SOUTHWEST FOR
A COUPLE HOURS. AS LOW PASSES...WINDS WILL BACK AROUND TO
NORTHWEST. WINDS SPEEDS WILL RAMP UP LATE AFTERNOON AND EVENING.
ALLSOPP
PREVIOUS DISCUSSION 12Z...
THE LARGE NE-SW BAND OF RAIN CONTINUED TO SHIFT FURTHER AWAY TO
THE EAST OVERNIGHT AND EARLY THIS MORNING. MEANWHILE...LIGHT RAIN
WAS QUICKLY ENDING ACROSS NORTHERN IL AND NORTHEAST IN AS A DRY
SLOT...QUITE EVIDENT IN BOTH WATER VAPOR SATELLITE AND COMPOSITE
RADAR LOOPS...CONTINUES TO PUNCH ACROSS NORTHERN IL INTO FAR
SOUTHERN WI EARLY THIS MORNING. PRECIPITATION SHOULD BE LIMITED
TO DRIZZLE AND SPOTTY SHOWERS UNTIL MIDDAY WITH THE DRYING ALOFT
BUT SMALL DEW POINT DEPRESSIONS PERSISTING IN THE LOW LEVELS.
THE MID LEVELS ARE SHOWN TO MOISTEN UP AGAIN BY LATE MORNING AS
THE POSITIVELY TILTED MID AND UPPER LEVEL TROUGHS SHIFT EASTWARD
AND ACROSS THE LOCAL AREA DURING THE LATE MORNING THROUGH EARLY
EVENING. THIS WILL RESULT IN A RETURN OF MORE SIGNIFICANT
PRECIPITATION TO THE AREA.
WITH COLD AIR AS FAR SOUTH AS NM AND NORTHERN TX COLD AIR
ADVECTION WILL BE OCCURRING IN THE MID AND LOWER LEVELS DESPITE
THE SOUTHWEST FLOW AHEAD OF THE TROUGHS. A NORTHEAST TO SOUTHWEST
ORIENTED COLD FRONT MOVED ACROSS THE LOCAL AREA DURING THE NIGHT
SHIFTING WINDS TO OUT OF THE NORTH AND NORTHEAST. THIS BROUGHT
COLDER BOUNDARY LAYER AIR TO THE AREA. LOW LEVEL COLD AIR
ADVECTION WILL INCREASE DURING THE LATE MORNING AND AFTERNOON AS
LOW PRESSURE MOVES NORTHEAST FROM NORTHEAST MO/WEST CENTRAL IL TO
FAR NORTHEAST IL BY 18Z.
BY MIDDAY MODEL TEMPERATURE PROFILES SHOW ALL BUT THE NEAR GROUND
LEVEL TO BE ALL BELOW 0C. AS THE PRECIPITATION RETURNS IT WILL
LIKELY BE A MIX OF RAIN AND SNOW BEFORE TURNING TO ALL LIGHT SNOW
BY EARLY AFTERNOON. THIS LIGHT SNOW WILL END IN THE EARLY EVENING
AS THE UPPER TROUGH AXIS MOVES EAST OF THE AREA.
WITH NARROW TEMPERATURE AND DEW POINT SPREADS ON BOTH SIDES OF THE
FRONT SLICING ACROSS FAR SOUTHWEST LOWER MI TO NORTHEAST MO IFR
STRATUS CEILINGS ARE EXPECTED TO PERSIST INTO TONIGHT. DURING
TONIGHT THE LOWEST LEVELS DRY SOMEWHAT SO CLOUD BASES SHOULD RISE
TO MVFR.
AS THE SURFACE LOW CONTINUES ON NORTHEASTWARD FROM NORTHEAST IL
ACROSS THE GREAT LAKES LATER TODAY WHILE A RIDGE OF HIGH PRESSURE
BUILDS SOUTH-SOUTHEAST ACROSS THE NORTHERN PLAINS THE PRESSURE
GRADIENT ACROSS THE AREA TIGHTENS CONSIDERABLY BY LATE
MORNING/EARLY AFTERNOON. SUSTAINED WINDS OF 15 TO 20KT WITH GUSTS
TO AROUND 30KT ARE LIKELY BY EARLY AFTERNOON. WINDS WILL BE
GRADUALLY BACKING TO NORTHWEST AND WEST-NORTHWEST AS THE LOW
MOVES FURTHER AWAY AND THE COLD FRONT SINKS INTO CENTRAL IN AND
SOUTHERN IL.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WIND FORECAST
* MEDIUM CONFIDENCE IN CIG/VSBY FORECAST
* LOW CONFIDENCE IN ANY ACCUMULATING SNOW
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR...THEN MVFR AND A CHANCE OF SNOW OVERNIGHT.
SATURDAY...MVFR BECOMING VFR.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR.
TRS
&&
.MARINE...
345 AM CST
RAPIDLY CHANGING WINDS ARE ONGOING ACROSS THE LAKE AS A TROUGH OF
LOW PRESSURE SITUATED ACROSS THE REGION CONTINUES TO SLOWLY WORK
ITS WAY TO THE NORTHEAST TODAY. AS THIS OCCURS...THE PRESSURE
GRADIENT WILL BECOME MORE ORGANIZED WITH STRONG NORTHERLY WINDS
PICKING UP THROUGHOUT THE DAY. EXPECT NORTHERLY WINDS TO 30 KT
THIS MORNING TO CONTINUE INCREASING TO GALES TODAY AND THIS
EVENING...WITH NOW A PORTION OF THE NEARSHORE WATERS OBSERVING
THESE NORTHERLY GALES. HAVE MAINTAINED A MENTION OF GALES TO 40 KT
FOR A PERIOD LATER TODAY...AS WINDS TURN MORE TOWARDS THE
NORTHWEST AND WEST LATER TONIGHT. AS THIS OCCURS...EXPECT WINDS TO
ALSO DIMINISH TO 30 KT THURSDAY MORNING BUT WITH THESE WESTERLY
WINDS TO 30 KT CONTINUING TO AT LEAST FRIDAY MORNING. ALTHOUGH NOT
LIKELY AT THIS TIME...THERE DOES APPEAR TO BE A BRIEF WINDOW OF
SOME WEST/NORTHWEST GALES DURING THE OVERNIGHT HOURS THURSDAY
NIGHT. WILL NEED TO CONTINUE TO MONITOR THIS GALE POTENTIAL
THURSDAY NIGHT...ALSO AS STRONGER WESTERLY WINDS IN THE NEARSHORE
PERSIST AT LEAST THROUGH LATE THURSDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008 UNTIL 4 PM
WEDNESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
944 AM CST WED JAN 30 2013
.DISCUSSION...
944 AM CST
A WEAK SECONDARY SURFACE LOW IS MAKING ITS WAY THROUGH NORTHERN IL
THIS MORNING WITH ARCTIC AIR SLOWLY SPILLING INTO WESTERN IL.
FREEPORT IL HAS ALREADY TURNED OVER TO SNOW AND GETTING REPORTS
OF RAIN MIXING WITH SLEET FROM DIXON AND ROCKFORD. AS TEMPS FALL
TODAY EXPECTING RAIN TO QUICKLY CHANGE OVER TO SNOW WITH A BRIEF
PERIOD OF SLEET/ICE PELLETS POSSIBLE. NOT EXPECTING ANY
SIGNIFICANT IMPACTS FROM SLEET/ICE PELLETS.
FOR THE WINTER WEATHER ADVISORY FOR WINNEBAGO...OGLE...AND BOONE
COUNTIES...WILL KEEP IT GOING BUT THINKING THE BEST FORCING WILL
OCCUR WHEN TEMPS ARE ABOVE FREEZING. THE UPPER LEVEL JET STREAKS
LEFT EXIT REGION IS OVER NORTHERN IL WHILE THE SPC RAP AND OTHER
GUIDANCE INDICATE A BAND OF 850 MB FRONTOGENESIS EXTENDING FROM
SOUTHERN WI THROUGH MOLINE IL. NEGATIVE EPV LIES ABOVE THE
FRONTOGENESIS WHICH WOULD SUPPORT BANDS OF LOCALLY HEAVIER
SNOWFALL. HOWEVER...THE FRONTOGENESIS IS EXPECTED TO WEAKEN
SIGNIFICANTLY THROUGH THE EARLY AFTERNOON HOURS SO THINKING THE
HEAVIEST SNOW WILL FALL THROUGH 3PM AT THE LATEST ACROSS THE
ADVISORY AREA. GIVEN THAT RAIN IS JUST TURNING OVER TO SNOW
NOW...AGREE WITH THE PREVIOUS FORECAST THAT THE ADVISORY CRITERIA
WILL PROBABLY ONLY BE MET IN ISOLATED LOCATIONS. OVERALL EXPECTING
2-4 INCHES OF SNOW IN THE ADVISORY AREA WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IF A MESOSCALE BAND SETS UP OVER THE AREA.
AS TEMPS FALL THROUGH THE DAY RAIN WILL TURN OVER TO SNOW
THROUGHOUT THE DAY. ROUGH TIMINGS ARE ALL SNOW ACROSS THE ADVISORY
AREA BY NOON...NORTH OF I-55 BY 4-5 PM...CHICAGO BY 5-6 PM...AND
ALL SNOW ACROSS THE AREA BY 7-8PM. EXPECTING A WET SNOW AS IT
FIRST TURNS OVER THEN BECOMING A MORE AVERAGE SNOW LATE THIS
AFTERNOON/EVENING. ONCE AGAIN EXPECTING 2-4 INCHES IN THE
NORTHWEST CORNER OF THE CWA...1-2 INCHES NORTH OF A MENDOTA TO
WAUKEGAN LINE...AND LESS THAN AN INCH ELSEWHERE.
JEE
&&
.PREV DISCUSSION...
353 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE POTENTIAL FOR SNOW
TODAY...CLOUD COVER AND ITS POTENTIAL IMPACTS ON TEMPS...AND CLIPPER
SYSTEM ARRIVING FRIDAY NIGHT INTO SATURDAY.
VERY TRICKY FORECAST TODAY AS COLDER AIR SPILLS INTO THE REGION AND
PORTIONS OF THE CWA POTENTIALLY GET CLIPPED BY TROWAL. HAVE OPTED TO
ISSUE A WINTER WX ADVISORY FOR MY NW 3 COUNTIES MOSTLY DUE TO MODEL
GUIDANCE AND TO MAKE A PRETTIER WATCH/WARNING/ADVISORY MAP BUT HAVE
SERIOUS DOUBTS ABOUT WHETHER IT WILL COME CLOSE TO VERIFYING BASED
ON CURRENT TRENDS IN OBSERVATIONAL DATA. WARM CONVEYOR BELT WITH
ITS MASSIVE STREAM OF RAIN CONTINUES TO SHIFT EASTWARD AND OUT OF
THE CWA EARLY THIS MORNING AND WOULD ANTICIPATE THIS TREND TO
CONTINUE AS WATER VAPOR IMAGERY SHOWS MASSIVE DEVELOPING MID LEVEL
DRY INTRUSION PUNCHING NORTHEAST INTO THE REGION. SURFACE ANALYSIS
HAS ANOTHER IN SEEMING CONGA LINE OF LOWS OVER MISSOURI STILL AT
09Z...AS THIS LOW TRANSLATES NORTHEAST INTO ILLINOIS EARLY THIS
MORNING IT WILL ACT TO SLOW THE INTRUSION OF COLD AIR AND LIKELY
DELAY THE RAIN/SNOW TRANSITION LINE FROM MAKING GOOD HEADWAY ACROSS
THE CWA UNTIL IT LIFTS OUT OF THE AREA TOWARD MIDDAY.
PROFILERS AND OBJECTIVE ANALYSIS HAVE A 120KT+ 500MB JET PUNCHING NE
INTO THE DRY INTRUSION WITH STRONG ASCENT TO THE LEFT OF THIS JET
SUPPORTING AN INTENSIFYING TROWAL THIS MORNING OVER IOWA AND
NORTHEAST MISSOURI. SUSPECT THAT THIS MORNING INTO THE EARLY
AFTERNOON AS THE DRY INTRUSION MOVES IN THAT THE PREDOMINANT PRECIP
TYPE WILL SHIFT TO DRIZZLE AND VERY LIGHT RAIN...THOUGH AS THE VORT
NEAR MCI MOVES EAST COULD SEE SOME SHOWERS REDEVELOPING IMMEDIATELY
IN ADVANCE OF THIS FEATURE. BY MIDDAY/EARLY AFTERNOON THE TROWAL
OVER IOWA/NORTHWEST MO WILL BEGIN TO TRANSLATE EAST INTO NORTHERN
ILLINOIS...BUT BY THAT POINT INSTABILITY WILL BE WEAKENING AND
BECOMING MORE FOCUSED TO OUR NORTH. ALSO...STRONG SYNOPTIC ASCENT
WILL ALSO BE SHIFTING NORTH INTO WI/MI AS THE MID LEVEL JET STREAK
PUNCH NORTH INTO THE UPPER GREAT LAKES. SUSPECT THAT THIS WILL LEAVE
OUR CWA WITH A GLANCING BLOW FROM THE DECAYING SOUTHERN FLANKS OF
WHAT WILL BE A VERY HEALTHY TROWEL THIS MORNING. COMPUTER MODELS AND
HPC GUIDANCE WOULD SUGGEST A SWATH OF 3 TO 5 INCHES OF SNOW ACROSS
OUR NORTHWEST CWA WHERE I PLACED THE ADVISORY...WHILE WHAT I`M
LOOKING AT IN OBSERVATIONAL DATA MAKE ME WONDER IF WE`LL BE ABLE TO
SQUEEZE OUT EVEN 2 INCHES. AS A COMPROMISE WILL GO WITH 2 TO 4
INCHES "POSSIBLE" WORDING AND PUT OUT AN ADVISORY TO BLEND WITH
NEIGHBORS AND ERR ON THE SIDE OF CAUTION...BUT DEFINITELY SEEING
SOME BUST POTENTIAL IN THIS FORECAST.
ACROSS THE REMAINDER OF THE CWA EXPECT DRIZZLY/SHOWERY WEATHER MUCH
OF THE DAY WITH A TRANSITION FROM RAIN TO SNOW TAKING PLACE FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. SUPPOSE THERE COULD BE UP TO
AN INCH OF ACCUMULATION FROM THE REMNANTS OF THE TROWAL BUT NOT
LOOKING TO BE A TERRIBLY BIG DEAL. IN FACT...THE FALLING TEMPS AND
BLUSTERY WINDS WILL PROBABLY BE THE BIGGER STORY FOR MOST.
DEEP TROUGH THEN ESTABLISHES ITSELF OVER THE GREAT LAKES AND
NORTHEAST FOR THE REMAINDER OF THE WEEK. FORECAST SOUNDINGS SHOW THE
PRESENCE OF A STOUT FRONTAL INVERSION WHICH OFTEN TRAPS
MOISTURE/STRATUS THIS TIME OF YEAR...PARTICULARLY WITH THE CYCLONIC
LOW LEVEL FLOW FORECAST TO BE IN PLACE THROUGH THE REST OF THE WORK
WEEK. GUIDANCE CONTINUE TO FORECAST H8 TEMPS DROPPING TO -20C OR A
BIT COLDER BY THURSDAY AFTERNOON...SO CERTAINLY LOOKS TO BE A VERY
FORMIDABLE SHOT OF ARCTIC AIR. HOWEVER...HAVE GENERALLY TRENDED
TEMPS TOWARD THE WARMEST AVAILABLE GUIDANCE TONIGHT AS STRONG WINDS
AND STRATUS ARE EXPECTED TO HELP KEEP TEMPS UP. AS SECONDARY SURGE
OF ARCTIC AIR ARRIVES THURSDAY PROBABLY WILL SEE VERY LITTLE
RECOVERY INTO TEMPS AND WITH CLOUDS LIKELY TO LINGER THURSDAY NIGHT
AGAIN WENT WITH THE WARMER SIDE OF GUIDANCE. THE EXPECTED LACK OF
SNOW COVER WOULD ALSO TEND TO SUPPORT NOT GOING AS COLD AS MOS
NUMBERS FOR THIS TIME PERIOD.
PRECIP WISE AFTER TODAY NOT ANTICIPATING ANY BIG PRECIP THREAT UNTIL
FRIDAY NIGHT. HOWEVER...THE PRESENCE OF A STRATUS DECK WITH TEMPS
FROM THE SFC TO 700MB PROGGED TO DROP INTO THE PRIME DENDRITIC
GROWTH RANGE SUGGESTS THAT IT WILL TAKE VERY LITTLE FORCING FOR THIS
DECK TO LEAK FLURRIES OR EVEN LIGHT SNOW. THE BEST CHANCE OF "FLAKY
STRATUS" LOOKS TO BE THURSDAY INTO THURSDAY NIGHT AS THAT SECONDARY
SURGE OF COLD AIR ARRIVES...BUT JUST ABOUT ANY WEAK IMPULSE PIVOTING
AROUND THE TROUGH COULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW OR
FLURRIES.
STRONGER CLIPPER IS STILL PROGGED TO ZIP SOUTHEAST INTO THE REGION
FRIDAY NIGHT INTO SATURDAY AND GIVEN THE COLD AIR MASS IN PLACE
COULD EASILY WRING OUT A SWATH OF A COUPLE/FEW INCHES OF SNOW.
GUIDANCE STILL SUGGESTS THAT THE BEST CHANCES OF THIS WOULD BE IN
OUR SOUTHERN CWA AND GIVEN A COUPLE DAYS OF CONSISTENCY IN THE
MODELS HAVE GONE ABOVE GUIDANCE POPS AND NUDGED UP TO LOW END
LIKELYS. OBVIOUSLY AS WE GET CLOSER TO THE EVENT THE TRACK COULD
NEED TO BE NUDGED NORTH OR SOUTH...BUT DOES LOOKS LIKE SOMEWHERE IN
THE NEIGHBORHOOD STANDS A DECENT SHOT OF SOME ACCUMULATING SNOW. A
MODERATING TREND STILL APPEARS TO BE IN THE OFFING LATER IN THE
WEEKEND INTO EARLY NEXT WEEK AS THE UPPER FLOW FLATTENS OUT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHEAST WINDS LESS THAN 10 KT NOT TURNING NORTHWEST TIL AROUND
17-19Z
* IFR CIG/VSBY IN LIGHT RAIN DRIZZLE...MIXING WITH/CHANGING TO
SNOW AFTERNOON
* NORTHWEST WINDS INCREASING AND GUSTING TO NEAR 30 KT LATE AFTN
AND EVENING
ALLSOPP
//DISCUSSION...UPDATED 14Z
WEAK LOW PRESSURE OVER CENTRAL IL WILL MOVE OVER CHICAGO AROUND
18Z. THIS WILL GIVE ORD AND DPA NE WINDS THIS MORNING. MDW AND GYY
MAY GO LIGHT AND VARIABLE AND GYY MAY EVEN GO LIGHT SOUTHWEST FOR
A COUPLE HOURS. AS LOW PASSES...WINDS WILL BACK AROUND TO
NORTHWEST. WINDS SPEEDS WILL RAMP UP LATE AFTERNOON AND EVENING.
ALLSOPP
PREVIOUS DISCUSSION 12Z...
THE LARGE NE-SW BAND OF RAIN CONTINUED TO SHIFT FURTHER AWAY TO
THE EAST OVERNIGHT AND EARLY THIS MORNING. MEANWHILE...LIGHT RAIN
WAS QUICKLY ENDING ACROSS NORTHERN IL AND NORTHEAST IN AS A DRY
SLOT...QUITE EVIDENT IN BOTH WATER VAPOR SATELLITE AND COMPOSITE
RADAR LOOPS...CONTINUES TO PUNCH ACROSS NORTHERN IL INTO FAR
SOUTHERN WI EARLY THIS MORNING. PRECIPITATION SHOULD BE LIMITED
TO DRIZZLE AND SPOTTY SHOWERS UNTIL MIDDAY WITH THE DRYING ALOFT
BUT SMALL DEW POINT DEPRESSIONS PERSISTING IN THE LOW LEVELS.
THE MID LEVELS ARE SHOWN TO MOISTEN UP AGAIN BY LATE MORNING AS
THE POSITIVELY TILTED MID AND UPPER LEVEL TROUGHS SHIFT EASTWARD
AND ACROSS THE LOCAL AREA DURING THE LATE MORNING THROUGH EARLY
EVENING. THIS WILL RESULT IN A RETURN OF MORE SIGNIFICANT
PRECIPITATION TO THE AREA.
WITH COLD AIR AS FAR SOUTH AS NM AND NORTHERN TX COLD AIR
ADVECTION WILL BE OCCURRING IN THE MID AND LOWER LEVELS DESPITE
THE SOUTHWEST FLOW AHEAD OF THE TROUGHS. A NORTHEAST TO SOUTHWEST
ORIENTED COLD FRONT MOVED ACROSS THE LOCAL AREA DURING THE NIGHT
SHIFTING WINDS TO OUT OF THE NORTH AND NORTHEAST. THIS BROUGHT
COLDER BOUNDARY LAYER AIR TO THE AREA. LOW LEVEL COLD AIR
ADVECTION WILL INCREASE DURING THE LATE MORNING AND AFTERNOON AS
LOW PRESSURE MOVES NORTHEAST FROM NORTHEAST MO/WEST CENTRAL IL TO
FAR NORTHEAST IL BY 18Z.
BY MIDDAY MODEL TEMPERATURE PROFILES SHOW ALL BUT THE NEAR GROUND
LEVEL TO BE ALL BELOW 0C. AS THE PRECIPITATION RETURNS IT WILL
LIKELY BE A MIX OF RAIN AND SNOW BEFORE TURNING TO ALL LIGHT SNOW
BY EARLY AFTERNOON. THIS LIGHT SNOW WILL END IN THE EARLY EVENING
AS THE UPPER TROUGH AXIS MOVES EAST OF THE AREA.
WITH NARROW TEMPERATURE AND DEW POINT SPREADS ON BOTH SIDES OF THE
FRONT SLICING ACROSS FAR SOUTHWEST LOWER MI TO NORTHEAST MO IFR
STRATUS CEILINGS ARE EXPECTED TO PERSIST INTO TONIGHT. DURING
TONIGHT THE LOWEST LEVELS DRY SOMEWHAT SO CLOUD BASES SHOULD RISE
TO MVFR.
AS THE SURFACE LOW CONTINUES ON NORTHEASTWARD FROM NORTHEAST IL
ACROSS THE GREAT LAKES LATER TODAY WHILE A RIDGE OF HIGH PRESSURE
BUILDS SOUTH-SOUTHEAST ACROSS THE NORTHERN PLAINS THE PRESSURE
GRADIENT ACROSS THE AREA TIGHTENS CONSIDERABLY BY LATE
MORNING/EARLY AFTERNOON. SUSTAINED WINDS OF 15 TO 20KT WITH GUSTS
TO AROUND 30KT ARE LIKELY BY EARLY AFTERNOON. WINDS WILL BE
GRADUALLY BACKING TO NORTHWEST AND WEST-NORTHWEST AS THE LOW
MOVES FURTHER AWAY AND THE COLD FRONT SINKS INTO CENTRAL IN AND
SOUTHERN IL.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* WINDS...MEDIUM-HIGH
* CIG/VSBY...MEDIUM-HIGH
* SNOW...LOW-MEDIUM
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR...THEN MVFR AND A CHANCE OF SNOW OVERNIGHT.
SATURDAY...MVFR BECOMING VFR.
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR.
TRS
&&
.MARINE...
345 AM CST
RAPIDLY CHANGING WINDS ARE ONGOING ACROSS THE LAKE AS A TROUGH OF
LOW PRESSURE SITUATED ACROSS THE REGION CONTINUES TO SLOWLY WORK
ITS WAY TO THE NORTHEAST TODAY. AS THIS OCCURS...THE PRESSURE
GRADIENT WILL BECOME MORE ORGANIZED WITH STRONG NORTHERLY WINDS
PICKING UP THROUGHOUT THE DAY. EXPECT NORTHERLY WINDS TO 30 KT
THIS MORNING TO CONTINUE INCREASING TO GALES TODAY AND THIS
EVENING...WITH NOW A PORTION OF THE NEARSHORE WATERS OBSERVING
THESE NORTHERLY GALES. HAVE MAINTAINED A MENTION OF GALES TO 40 KT
FOR A PERIOD LATER TODAY...AS WINDS TURN MORE TOWARDS THE
NORTHWEST AND WEST LATER TONIGHT. AS THIS OCCURS...EXPECT WINDS TO
ALSO DIMINISH TO 30 KT THURSDAY MORNING BUT WITH THESE WESTERLY
WINDS TO 30 KT CONTINUING TO AT LEAST FRIDAY MORNING. ALTHOUGH NOT
LIKELY AT THIS TIME...THERE DOES APPEAR TO BE A BRIEF WINDOW OF
SOME WEST/NORTHWEST GALES DURING THE OVERNIGHT HOURS THURSDAY
NIGHT. WILL NEED TO CONTINUE TO MONITOR THIS GALE POTENTIAL
THURSDAY NIGHT...ALSO AS STRONGER WESTERLY WINDS IN THE NEARSHORE
PERSIST AT LEAST THROUGH LATE THURSDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008 UNTIL 4 PM
WEDNESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
346 AM CST WED JAN 30 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEW POINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WIND CHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* CONTINUED LIGHT RAIN PERSISTING TO AROUND SUNRISE.
* LIGHT RAIN SHOWERS MIXING/SWITCHING TO LIGHT SNOW LATE MORNING
TO EARLY AFTERNOON.
* ENDING OF LIGHT SNOW FIRST PART OF THIS EVENING.
* PREVAILING IFR...OCCASIONALLY MVFR...BECOMING PREVAILING MVFR
LATE AFTERNOON.
* WINDS BECOMING NORTH AROUND SUNRISE THEN NORTHWEST BY AFTERNOON.
* WINDS INCREASE DURING THE MORNING WITH GUSTS GENERALLY 25-30KT
FROM LATE MORNING THROUGH EVENING.
TRS
//DISCUSSION...UPDATED 09Z...
MAIN AREA OF RAIN STARTING TO MOVE NORTHEASTWARD OUT OF NORTHEAST
IL AS A SHORT WAVE LIFTS RAPIDLY NORTH-NORTHEAST ACROSS EASTERN
IA. RAIN WILL CONTINUE TO BECOME LESS WIDESPREAD/MORE SHOWERY
ACROSS THE LOCAL AREA BY DAWN AS A DRY SLOT...QUITE EVIDENT IN
BOTH WATER VAPOR SATELLITE AND COMPOSITE RADAR LOOPS...PUNCHES
ACROSS NORTHERN IL THIS MORNING.
TRS
PREVIOUS DISCUSSION...UPDATED 06Z...
LARGE NE-SW BAND OF HEAVIER RAIN HAS BEEN SHIFTING EAST DURING
THE EVENING AND AS OF LATE EVENING WAS EAST HAD PROGRESSED TO THE
EAST OF ORD AND MDW. A BROAD BAND OF MAINLY LIGHT RAIN EXTENDED
WESTWARD FROM THE HEAVIER RAIN BACK TO SOUTH CENTRAL WI...WEST
CENTRAL IL AND SOUTH CENTRAL MO AS ADDITIONAL SHORT WAVES LIFT
NORTHEAST AHEAD OF THE MAIN UPPER TROUGH WITH AN AXIS ALONG A
SOUTHWEST ONTARIO TO NORTHERN TX LINE. THIS TROUGH AXIS IS
PROGGED TO REACH SOUTHWEST WI...NORTHEAST MO AND WESTERN AR BY
18Z AS IS SHOWN CONTINUING EAST AND ACROSS THE LOCAL AREA DURING
THE LATE AFTERNOON AND EARLY EVENING.
EXPECTED PRECIPITATION TO PERSIST OVERNIGHT AND ALL THE WAY INTO
EARLY EVENING. THE RAIN WILL MIX/SWITCH TO LIGHT SNOW AROUND
MIDDAY AS A SOMEWHAT ILL DEFINED SURFACE LOW CURRENTLY OVER
NORTHEAST IL/FAR SOUTHERN LAKE MI/NORTHWEST IN PROGRESSES
NORTHEASTWARD THROUGH THE GREAT LAKES AND INTO ONTARIO BY 18Z...
SPREADING COLD AIR ACROSS THE AREA AS THE TRAILING COLD FRONT
PUSHES FURTHER EASTWARD.
BETWEEN AN INCREASING PRESSURE GRADIENT SPREADING WEST TO EAST
MIDDAY THROUGH EARLY EVENING NORTH-NORTHWEST TO NORTHWEST WINDS
WILL INCREASE...AND STRENGTHENING OF THE COLD AIR ADVECTION DURING
THIS TIME SUSTAINED WINDS OF 15-20KT AND GUSTS 25-30KT ARE
EXPECTED MIDDAY AND WELL INTO TONIGHT.
CEILINGS WILL STAY BELOW 010 INTO EARLY AFTERNOON THEN RISE A BIT
TO THE 015-020 RANGE AS DEW POINT DEPRESSIONS INCREASE TO A FEW
DEGREES IN THE COLD AIR. CEILINGS ARE FORECAST TO RISE TO AT OR
ABOVE 020 IN THE EARLY TO MID EVENING AS THIS IS WHEN THE LIGHT
SNOW IS EXPECTED TO END AND LOW LEVEL DEW POINT DEPRESSIONS
INCREASE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN TIMING OF SHITHC OVER FROM RAIN TO SNOW.
* MEDIUM CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE IN CEILING AND VISIBILITY TRENDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHANCE OF FLURRIES IN THE AFTERNOON/EVENING. MVFR CIGS
POSSIBLE. WEST WINDS GUSTING TO 25-30KT.
FRIDAY...VFR EARLY. CHANCE OF SNOW WITH MVFR CIGS/VIS OVERNIGHT.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS EARLY...THE VFR
OVERNIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...SLIGHT CHANCE RAIN/SNOW. MVFR CIGS/VIS POSSIBLE.
KREIN
&&
.MARINE...
345 AM CST
RAPIDLY CHANGING WINDS ARE ONGOING ACROSS THE LAKE AS A TROUGH OF
LOW PRESSURE SITUATED ACROSS THE REGION CONTINUES TO SLOWLY WORK
ITS WAY TO THE NORTHEAST TODAY. AS THIS OCCURS...THE PRESSURE
GRADIENT WILL BECOME MORE ORGANIZED WITH STRONG NORTHERLY WINDS
PICKING UP THROUGHOUT THE DAY. EXPECT NORTHERLY WINDS TO 30 KT
THIS MORNING TO CONTINUE INCREASING TO GALES TODAY AND THIS
EVENING...WITH NOW A PORTION OF THE NEARSHORE WATERS OBSERVING
THESE NORTHERLY GALES. HAVE MAINTAINED A MENTION OF GALES TO 40 KT
FOR A PERIOD LATER TODAY...AS WINDS TURN MORE TOWARDS THE
NORTHWEST AND WEST LATER TONIGHT. AS THIS OCCURS...EXPECT WINDS TO
ALSO DIMINISH TO 30 KT THURSDAY MORNING BUT WITH THESE WESTERLY
WINDS TO 30 KT CONTINUING TO AT LEAST FRIDAY MORNING. ALTHOUGH NOT
LIKELY AT THIS TIME...THERE DOES APPEAR TO BE A BRIEF WINDOW OF
SOME WEST/NORTHWEST GALES DURING THE OVERNIGHT HOURS THURSDAY
NIGHT. WILL NEED TO CONTINUE TO MONITOR THIS GALE POTENTIAL
THURSDAY NIGHT...ALSO AS STRONGER WESTERLY WINDS IN THE NEARSHORE
PERSIST AT LEAST THROUGH LATE THURSDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008...9 AM WEDNESDAY
TO 4 PM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 9 AM
THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
345 AM CST WED JAN 30 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEW POINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WIND CHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* CONTINUED LIGHT RAIN PERSISTING TO AROUND SUNRISE.
* LIGHT RAIN SHOWERS MIXING/SWITCHING TO LIGHT SNOW LATE MORNING
TO EARLY AFTERNOON.
* ENDING OF LIGHT SNOW FIRST PART OF THIS EVENING.
* PREVAILING IFR...OCCASIONALLY MVFR...BECOMING PREVAILING MVFR
LATE AFTERNOON.
* WINDS BECOMING NORTH AROUND SUNRISE THEN NORTHWEST BY AFTERNOON.
* WINDS INCREASE DURING THE MORNING WITH GUSTS GENERALLY 25-30KT
FROM LATE MORNING THROUGH EVENING.
TRS
//DISCUSSION...UPDATED 09Z...
MAIN AREA OF RAIN STARTING TO MOVE NORTHEASTWARD OUT OF NORTHEAST
IL AS A SHORT WAVE LIFTS RAPIDLY NORTH-NORTHEAST ACROSS EASTERN
IA. RAIN WILL CONTINUE TO BECOME LESS WIDESPREAD/MORE SHOWERY
ACROSS THE LOCAL AREA BY DAWN AS A DRY SLOT...QUITE EVIDENT IN
BOTH WATER VAPOR SATELLITE AND COMPOSITE RADAR LOOPS...PUNCHES
ACROSS NORTHERN IL THIS MORNING.
TRS
PREVIOUS DISCUSSION...UPDATED 06Z...
LARGE NE-SW BAND OF HEAVIER RAIN HAS BEEN SHIFTING EAST DURING
THE EVENING AND AS OF LATE EVENING WAS EAST HAD PROGRESSED TO THE
EAST OF ORD AND MDW. A BROAD BAND OF MAINLY LIGHT RAIN EXTENDED
WESTWARD FROM THE HEAVIER RAIN BACK TO SOUTH CENTRAL WI...WEST
CENTRAL IL AND SOUTH CENTRAL MO AS ADDITIONAL SHORT WAVES LIFT
NORTHEAST AHEAD OF THE MAIN UPPER TROUGH WITH AN AXIS ALONG A
SOUTHWEST ONTARIO TO NORTHERN TX LINE. THIS TROUGH AXIS IS
PROGGED TO REACH SOUTHWEST WI...NORTHEAST MO AND WESTERN AR BY
18Z AS IS SHOWN CONTINUING EAST AND ACROSS THE LOCAL AREA DURING
THE LATE AFTERNOON AND EARLY EVENING.
EXPECTED PRECIPITATION TO PERSIST OVERNIGHT AND ALL THE WAY INTO
EARLY EVENING. THE RAIN WILL MIX/SWITCH TO LIGHT SNOW AROUND
MIDDAY AS A SOMEWHAT ILL DEFINED SURFACE LOW CURRENTLY OVER
NORTHEAST IL/FAR SOUTHERN LAKE MI/NORTHWEST IN PROGRESSES
NORTHEASTWARD THROUGH THE GREAT LAKES AND INTO ONTARIO BY 18Z...
SPREADING COLD AIR ACROSS THE AREA AS THE TRAILING COLD FRONT
PUSHES FURTHER EASTWARD.
BETWEEN AN INCREASING PRESSURE GRADIENT SPREADING WEST TO EAST
MIDDAY THROUGH EARLY EVENING NORTH-NORTHWEST TO NORTHWEST WINDS
WILL INCREASE...AND STRENGTHENING OF THE COLD AIR ADVECTION DURING
THIS TIME SUSTAINED WINDS OF 15-20KT AND GUSTS 25-30KT ARE
EXPECTED MIDDAY AND WELL INTO TONIGHT.
CEILINGS WILL STAY BELOW 010 INTO EARLY AFTERNOON THEN RISE A BIT
TO THE 015-020 RANGE AS DEW POINT DEPRESSIONS INCREASE TO A FEW
DEGREES IN THE COLD AIR. CEILINGS ARE FORECAST TO RISE TO AT OR
ABOVE 020 IN THE EARLY TO MID EVENING AS THIS IS WHEN THE LIGHT
SNOW IS EXPECTED TO END AND LOW LEVEL DEW POINT DEPRESSIONS
INCREASE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN TIMING OF SHITHC OVER FROM RAIN TO SNOW.
* MEDIUM CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE IN CEILING AND VISIBILITY TRENDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHANCE OF FLURRIES IN THE AFTERNOON/EVENING. MVFR CIGS
POSSIBLE. WEST WINDS GUSTING TO 25-30KT.
FRIDAY...VFR EARLY. CHANCE OF SNOW WITH MVFR CIGS/VIS OVERNIGHT.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS EARLY...THE VFR
OVERNIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...SLIGHT CHANCE RAIN/SNOW. MVFR CIGS/VIS POSSIBLE.
KREIN
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008...9 AM WEDNESDAY
TO 4 PM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 9 AM
THURSDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
111 AM CST WED JAN 30 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEW POINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WIND CHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CONTINUED LIGHT RAIN...OCCASIONALLY MODERATE...PERSISTING INTO
LATE MORNING...THEN MIXING/SWITCHING TO LIGHT SNOW DURING LATE
MORNING TO EARLY AFTERNOON BEFORE ENDING FIRST PART OF EVENING..
* PREVAILING IFR INTO LATE AFTERNOON...THEN MVFR THROUGH THE
EVENING.
* WINDS BECOME NORTH TO NORTHWEST AND INCREASE DURING THE
MORNING...WITH GUSTS GENERALLY 25-30KT FROM MIDDAY AND THROUGH
THE EVENING.
TRS
//DISCUSSION...UPDATED 06Z...
LARGE NE-SW BAND OF HEAVIER RAIN HAS BEEN SHIFTING EAST DURING
THE EVENING AND AS OF LATE EVENING WAS EAST HAD PROGRESSED TO THE
EAST OF ORD AND MDW. A BROAD BAND OF MAINLY LIGHT RAIN EXTENDED
WESTWARD FROM THE HEAVIER RAIN BACK TO SOUTH CENTRAL WI...WEST
CENTRAL IL AND SOUTH CENTRAL MO AS ADDITIONAL SHORT WAVES LIFT
NORTHEAST AHEAD OF THE MAIN UPPER TROUGH WITH AN AXIS ALONG A
SOUTHWEST ONTARIO TO NORTHERN TX LINE. THIS TROUGH AXIS IS
PROGGED TO REACH SOUTHWEST WI...NORTHEAST MO AND WESTERN AR BY
18Z AS IS SHOWN CONTINUING EAST AND ACROSS THE LOCAL AREA DURING
THE LATE AFTERNOON AND EARLY EVENING.
EXPECTED PRECIPITATION TO PERSIST OVERNIGHT AND ALL THE WAY INTO
EARLY EVENING. THE RAIN WILL MIX/SWITCH TO LIGHT SNOW AROUND
MIDDAY AS A SOMEWHAT ILL DEFINED SURFACE LOW CURRENTLY OVER
NORTHEAST IL/FAR SOUTHERN LAKE MI/NORTHWEST IN PROGRESSES
NORTHEASTWARD THROUGH THE GREAT LAKES AND INTO ONTARIO BY 18Z...
SPREADING COLD AIR ACROSS THE AREA AS THE TRAILING COLD FRONT
PUSHES FURTHER EASTWARD.
BETWEEN AN INCREASING PRESSURE GRADIENT SPREADING WEST TO EAST
MIDDAY THROUGH EARLY EVENING NORTH-NORTHWEST TO NORTHWEST WINDS
WILL INCREASE...AND STRENGTHENING OF THE COLD AIR ADVECTION DURING
THIS TIME SUSTAINED WINDS OF 15-20KT AND GUSTS 25-30KT ARE
EXPECTED MIDDAY AND WELL INTO TONIGHT.
CEILINGS WILL STAY BELOW 010 INTO EARLY AFTERNOON THEN RISE A BIT
TO THE 015-020 RANGE AS DEW POINT DEPRESSIONS INCREASE TO A FEW
DEGREES IN THE COLD AIR. CEILINGS ARE FORECAST TO RISE TO AT OR
ABOVE 020 IN THE EARLY TO MID EVENING AS THIS IS WHEN THE LIGHT
SNOW IS EXPECTED TO END AND LOW LEVEL DEW POINT DEPRESSIONS
INCREASE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN PRECIPITATION TRENDS.
* MEDIUM CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE IN CEILING AND VISIBILITY TRENDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHANCE OF FLURRIES IN THE AFTERNOON/EVENING. MVFR CIGS
POSSIBLE. WEST WINDS GUSTING TO 25-30KT.
FRIDAY...VFR EARLY. CHANCE OF SNOW WITH MVFR CIGS/VIS OVERNIGHT.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS EARLY...THE VFR
OVERNIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...SLIGHT CHANCE RAIN/SNOW. MVFR CIGS/VIS POSSIBLE.
KREIN
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 6 AM
THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...6 AM WEDNESDAY TO
10 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...4 PM WEDNESDAY TO 4 AM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1135 PM CST TUE JAN 29 2013
.DISCUSSION...
ISSUED 905 PM CST TUE JAN 29 2013
INITIAL WIND SHIFT HAS PUSHED THROUGH ABOUT 3/4 OF THE CWA...
CURRENTLY EXTENDING FROM ABOUT EFFINGHAM TO DANVILLE. TEMPERATURES
STILL IN THE 60-65 RANGE AHEAD OF THIS AREA...WITH SOME GRADIENT
WIND GUSTS OF 35-40 MPH. THE MAIN COLD FRONT WAS LOCATED JUST EAST
OF THE IOWA BORDER...WHERE TEMPERATURES FALL INTO THE 30S. HAVE
HAD SOME WAVES OF LOW PRESSURE RIDING ALONG THE FRONT...WHICH HAS
SLOWED DOWN ITS PASSAGE SOMEWHAT...BUT LATEST MODEL GUIDANCE STILL
INDICATES IT SHOULD START MOVING THROUGH THE WESTERN CWA LATE
TONIGHT.
MAIN CONCERN REMAINS WITH THE RAIN TONIGHT AND THE FLOOD WATCH.
EVENING UPPER AIR SOUNDING FROM LINCOLN HAD PRECIPITABLE WATER
VALUES OF 1.43 INCHES...WHICH LOCAL RESEARCH INDICATES IS A RECORD
FOR JANUARY IN THIS AREA. SO FAR...HAVE SEEN LITTLE OR NO RAIN IN
THE FAR SOUTHEAST CWA...BUT THAT SHOULD BE INCREASING SHORTLY AS A
NARROW CONVECTIVE LINE FROM SALEM SOUTHWEST INTO MISSOURI MOVES
QUICKLY EASTWARD. RAP MODEL SHOWS THE SAME HIGH PWAT VALUES
AFFECTING SOUTHEAST ILLINOIS OVER THE NEXT SEVERAL HOURS...SO SOME
HEAVY RAIN THERE IS STILL LIKELY. THE WESTERN HALF OF THE CWA HAS
SEEN AMOUNTS OVER AN INCH COMMON WEST OF A BLOOMINGTON TO
JACKSONVILLE LINE...WITH SOME 1.5 TO 2 INCH TOTALS TOWARD THE
ILLINOIS RIVER VALLEY. HAVE KEPT THE FLOOD WATCH IN PLACE FOR
NOW OVER THE ENTIRE AREA...BUT HAVE SOME CONCERNS ABOUT THE
NORTHWEST CWA...AS REGIONAL RADAR MOSAICS SHOW THE HEAVIEST AXIS
OF RAIN FURTHER TO THE EAST. WILL WATCH THIS FOR A COUPLE MORE
HOURS BEFORE DECIDING WHETHER OR NOT TO TRIM DOWN THE WATCH AREA.
UPDATED ZONES/GRIDS HAVE BEEN SENT.
GEELHART
&&
.AVIATION...
ISSUED 1127 PM CST TUE JAN 29 2013
PRIMARY FRONTAL BOUNDARY ROUGHLY ALONG A KUIN-KSQI LINE AND WILL
PUSH SLOWLY EASTWARD THE NEXT SEVERAL HOURS. A WAVE OF LOW
PRESSURE RIDING ALONG THE FRONT WILL SLOW ITS PROGRESSION THROUGH
ABOUT 15Z...THEN AFTER THAT...WINDS WILL MORE CONSISTENTLY SWING
AROUND TO THE NORTHWEST. HIGHEST WINDS EXPECTED DURING THE
AFTERNOON AND EVENING...WITH SOME GUSTS EXCEEDING 30 KNOTS.
LARGE RAIN SHIELD WILL BECOME MORE SCATTERED IN NATURE OVER THE
NEXT FEW HOURS...HOWEVER A LARGER AREA OF PRECIPITATION WILL
REDEVELOP OVER MISSOURI AND IOWA BEFORE MOVING EASTWARD. FORECAST
SOUNDINGS ARE SLOWING THE TRANSITION TO SNOW A BIT...BUT SHOULD
SWITCH AROUND 14Z NEAR KPIA AND TOWARD 17Z AROUND KDEC. CEILINGS
HAVE BEEN DROPPING BACK INTO IFR RANGE OVER WEST CENTRAL ILLINOIS
AND THIS SHOULD BECOME MORE WIDESPREAD OVER THE NEXT FEW HOURS.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 320 PM CST TUE JAN 29 2013
MAIN CONCERN THIS FORECAST PACKAGE CONTINUES TO INVOLVE THE
POTENTIAL HEAVY RAIN/FLOOD WATCH EVENT FOR TONIGHT...WHEN RAIN
WILL CHANGE OVER TO SNOW...AND FALLING TEMPS IN THE SHORT TERM.
ALL MODELS IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL PATTERN
THROUGH THE SHORT TERM...AND WITH THE SFC FEATURES AND MOVEMENTS
THROUGH FRIDAY. EXTENDED MODELS HAVE TRENDED INTO BETTER AGREEMENT
IN THE EXTENDED WITH SFC FEATURES AS WELL. THEREFORE CONFIDENCE IS
ABOVE AVERAGE FOR THIS FORECAST PACKAGE.
SHORT TERM...TONIGHT THROUGH FRIDAY
A SFC LOW IN CENTRAL OKLAHOMA IS FORECAST TO CONTINUE TO MOVE
NORTHEAST ALONG A FRONTAL SYSTEM STRETCHING FROM WI...THROUGH
NORTHWESTERN IL...THROUGH MO AND INTO OK. THIS LOW WILL MOVE
ACROSS CENTRAL ILLINOIS THIS EVENING AND INTO SOUTHERN MICH JUST
AFTER MIDNIGHT. THE UPPER LEVEL TROUGH ASSOCIATED WITH THIS SFC
SYSTEM WILL REMAIN BACK IN THE CENTRAL US AND NOT MOVE INTO AND
THROUGH THE CWA UNTIL TOMORROW EVENING. THE TROUGH MOVES
THROUGH...BUT THEN BROADENS AS ANOTHER SMALLER AND LESS INTENSE SFC
LOW MOVES OUT OF THE PLAINS AND THROUGH SOUTHERN IL THURSDAY. THIS
WILL PUSH THROUGH QUICKLY AND THEN COLD HIGH PRSS MOVES BACK INTO
THE AREA FOR THUR NIGHT AND FRIDAY. SHOWERS AND THUNDERSTORMS WITH
HEAVY RAINFALL ARE FORECAST TO CONTINUE TO MOVE ACROSS THE CWA
TONIGHT. STORMS WILL BE MOVING VERY QUICKLY TO THE NORTHEAST THIS
EVENING AND COULD BE SEVERE AT TIMES WITH DAMAGING WINDS. TORNADO
WATCHES ARE ONGOING TO THE SOUTHWEST OF THE AREA...AND OUR CWA MAY
HAVE TO BE INCLUDED LATER THIS AFTERNOON AND INTO THIS EVENING IF
THE STORMS SOUTHWEST OF THE AREA MAINTAIN THEIR STRENGTH AS THEY
MOVE NORTHEAST. TOMORROW...THE PCPN WILL BEGIN TO CHANGE TO ALL
SNOW AS MUCH COLDER AIR ADVECTS INTO THE AREA. MODELS ARE FORECASTING
AN AREA OF DEFORMATION SNOW TO SETUP WEST OF THE TRACK OF THE SFC
LOW TOMORROW WITH THE HIGHEST ACCUMULATING SNOW STAYING NORTHWEST
OF THE IL RIVER. LOOKING FOR ABOUT AN INCH ALONG A RUSHVILLE TO
BLOOMINGTON LINE WITH UP TO AROUND 1.5 INCHES AROUND GALESBURG.
AMOUNTS OF A HALF AN INCH OR LESS WILL BE ALONG I-72. AS THIS
SYSTEM PULLS EAST AND NORTHEAST...A SLIGHT CHANCE OF SNOW WILL
CONTINUE ACROSS THE EXTREME NORTHEAST OF THE CWA WED NIGHT.
WITH THE TROUGH BROADENING...A SFC LOW WILL MOVE OUT OF THE PLAINS
AND THROUGH SOUTHERN IL THURSDAY. THIS WILL BRING A SLIGHT CHANCE
OF MORE SNOW TO THE WHOLE CWA...MAINLY THUR AFTERNOON. BEYOND
THIS...COLD ARCTIC HIGH PRSS WILL DROP INTO THE REGION WITH DRY
AND VERY COLD WEATHER FOR THUR NIGHT AND FRIDAY.
LOWS TONIGHT WILL BE CLOSE TO MIDNIGHT AND HIGHS TOMORROW WILL
PROBABLY BE JUST AFTER MIDNIGHT TONIGHT. TEMPS WILL THEN GRADUALLY
FALL TOMORROW THROUGH TOMORROW NIGHT. THEN COLDER AIR WILL ADVECT
INTO THE REGION FOR THUR NIGHT AND FRIDAY...WITH TEMPS AROUND ZERO
IN THE NORTHWEST TO IN THE LOWER TEENS IN THE SOUTHEAST...FOR THUR
NIGHT. FRI TEMPS WILL BE WELL BELOW NORMAL FOR FRIDAY AS
WELL...NOT REACHING ABOVE FREEZING ANYWHERE IN THE CWA.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODELS HAVE ANOTHER SFC LOW DROPPING ACROSS NORTHERN IL FRIDAY
NIGHT...SPREADING SOME LIGHT SNOW ACROSS THE NORTHEASTERN HALF OF
THE CWA. THIS CLIPPER SYSTEM WILL BE QUICK SO ACCUMULATIONS WILL
BE VERY LIGHT. BEYOND THIS...ANOTHER WEAK SYSTEM IS FORECAST TO
MOVE ACROSS THE AREA WITH LIGHT PCPN MON AND MONDAY NIGHT. FOR NOW
WILL KEEP ONLY SLIGHT CHC OF POPS IN THE FORECAST...WHICH WILL NOT
BE MENTIONED IN THE WORDED FORECAST. OTHER THAN THESE TWO
SYSTEMS...REMAINDER OF THE LONG TERM PERIODS WILL BE DRY.
TEMPS WILL START COLD BUT THEN WARM QUICKLY FOR THE WEEKEND AND
INTO THE BEGINNING OF NEXT WEEK. WARMEST DAY LOOKS TO BE MONDAY
WITH TEMPS 5+ DEGREES ABOVE NORMAL.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH UNTIL 6 AM CST WEDNESDAY FOR ILZ028>031-037-038-
042>046-051>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1235 PM EST WED JAN 30 2013
.AVIATION...
18Z TAFS...STRONG COLD FRONT CURRENTLY NEAR IN/IL STATE LINE PER
RECENT OBS WILL PUSH EAST ACROSS THE AREA LATE THIS AFTERNOON INTO
EVENING. IFR CONDS AT KSBN THIS AFTN WILL LIFT TO MVFR WITH
FROPA...CURRENTLY TIMED BETWEEN 23Z AND 01Z. SCATTERED RAIN AHEAD
OF THE FRONT WILL CHANGE OVER TO ALL SNOW AFTER 01Z AT KSBN...WITH
MVFR CIGS/VISBYS EXPECTED THROUGH THE OVERNIGHT. RECENT OBS AND
SAT TRENDS THIS AM/AFTN SHOW IFR CIGS JUST WEST OF KFWA...WITH
LOWERING CONFIDENCE OF IFR REACHING TERMINAL. REFLECTED WITH
TEMPO IFR CIGS THROUGH 20Z...AND SHOULD REMAIN MVFR AFTERWARD WITH
STRONGER GRADIENT AHEAD OF FRONT...SUPPORTED BY OB TRENDS. PRECIP
SHOULD BE MOSTLY ENDED AT KFWA WITH FROPA...HOWEVER SOME -SN MAY
BE PRESENT 03Z AND AFTER...BUT CONFIDENCE TOO LOW TO INCLUDE
MENTION IN THIS TAF ISSUANCE. WINDS GUSTING NEAR 30KTS EXPECTED
ALONG/BEHIND FROPA.
&&
.PREV DISCUSSION... /ISSUED 1033 AM EST WED JAN 30 2013/
UPDATE...
QUICK UPDATE SENT TO ADD IN MENTION OF DRIZZLE IN NW AREAS AS
INCREASING LL LIFT AND NEARLY SATURATED BOUNDARY LAYER AREA
RESULTING IN AREAS OF DRIZZLE EXPANDING ACROSS THE NW QUARTER TO
HALF OF THE AREA. THINK THIS WILL BE SHORT LIVED AS COLD FRONT
APPROACHES FROM THE SW WITH DEEPER FORCING AND MSTR. BROKEN LINE
OF SHOWERS ACCOMPANIES THE FRONT WITH HRRR RUNS OVER THE PAST
COUPLE OF HOURS SHOWING AN EXPANDING AREA OF SHOWERS WITH GUSTY
WINDS (30 TO 35 KTS). FOR THE TIME BEING LIKELY POPS INHERITED
FROM OVERNIGHT FORECAST WILL WORK. MAY NEED AN ADDITIONAL UPDATE
IN A FEW HOURS IF COVERAGE DOES EXPAND AS HINTED AT. CHANGE OVER
TIMING ALSO LOOKS REASONABLE AT THIS STATE WITH FAR W/NW AREAS
SEEING A MIX OR FULL SWITCH IN THE 22Z TO 01Z TIME FRAME AND THEN
MARCHING EAST TO THE IN/OH STATE LINE IN THE 00-03Z WINDOW.
PREV DISCUSSION... /ISSUED 409 AM EST WED JAN 30 2013/
SHORT TERM...
PREFNTL CONV LINE CONTS TO ACCELERATE EWD EARLY THIS MORNING IN
RESPONSE TO UPSTREAM SW TROUGH EJECTING NEWD OUT OF KS. PRIMARY CDFNT
STILL LAGS APPRECIABLY WWD AN ANCHORED TO SFC CYCLONE OVR NRN IL.
00Z GUIDANCE TAKEN AS A WHOLE MOSTLY AGREEABLE SHRT TERM W/CONTD
NEWD EJECTING OF MAIN UPR TROUGH AND EWD DRIVING WEDGE OF ARCTIC AIR
TONIGHT. WILL DELAY CDFNT PROGRESSION SLIGHTLY FM PRIOR FCST PER
UPSTREAM TRENDS AND NR TERM RUC/HRRR GUIDANCE. THIS ALSO
NECESSITATES A UPWARD BUMP/EXPANSION IN POPS NW HALF THIS AFTN FOR
COMBINATION OF REDVLPG SHRA ALG SFC BNDRY AND MID LVL DEFORMATION
ZONE CLIPPING NWRN AREAS LT. OTRWS RAPID DEEPENING OF LL CAA WING
WILL CHG THINGS OVR RAPIDLY W-E THIS EVENING HWVR PALTRY SNOW AMTS
XPCD...INCH OR LESS.
LL THERMAL TROUGH BLDS ACRS THE LAKES LTR TONIGHT AND MAXIMIZES INTO
FRI. WHILE INITIAL SHRT FETCH WRLY FLW TRAJECTORY LIMITING
OVERNIGHT...SECONDARY SW TROUGH DROPPING RAPIDLY SEWD OUT OF AB AND
ATTENDANT MID LVL MSTR PLUME SHLD SEED A PD OF ENHANCED LK EFFECT LT
THU AFTN THOUGH FRI AM ESP IN CONTEXT OF ADDNL LL VEERING AND MUCH
IMPROVED FETCH. PRIOR DELINEATION OF HIGHEST BOUND POPS DEEMED CLOSE
BUT DID ERODE SRN EXTENT PER LATEST CONSENSUS.
LONG TERM...FRIDAY THROUGH TUESDAY
LAKE EFFECT WILL BE TAPERING OFF DURING THE DAY FRIDAY. STOUT
SUBSIDENCE INVERSION WILL DEVELOP BY FRIDAY AFTERNOON IN THE WAKE OF
DEPARTING SHORTWAVE. MEANWHILE...LOW LEVEL WINDS WILL BACK TO THE
SOUTHWEST AS RIDGE AXIS QUICKLY SHIFTS EAST OF HERE. THESE TWO
PROCESSES WILL CAUSE LAKE EFFECT BANDS TO SHIFT NORTH AND WEAKEN AS
THE DAY PROGRESSES. THIS WILL TAKE SOME TIME THOUGH AND WITH
CONVECTIVE DEPTHS STILL AROUND 7 KFT AND WIND DIRECTION STILL AROUND
290 BY LATE FRIDAY MORNING...ADDITIONAL ACCUMULATIONS OF AROUND AN
INCH ARE POSSIBLE MAINLY IN BERRIEN AND CASS COUNTIES BETWEEN 12Z
AND 18Z. MAIN STORY FOR THE REST OF THE CWA WILL BE VERY COLD TEMPS.
THERMAL TROUGH WILL BE MOVING OVERHEAD FRIDAY MORNING WITH 925MB
TEMPS AROUND -18C. THERMAL PROFILES WILL START TO REBOUND BY LATE
FRIDAY WITH DEVELOPING SOUTHWEST FLOW BUT THIS WILL LIKELY BE TOO
LITTLE TOO LATE TO GET HIGHS OUT OF THE MID TO UPPER TEENS. DECENT
GRADIENT WILL ALSO SUPPORT WINDS OF 10-20 MPH...MAKING IT FEEL LIKE
THE SINGLE DIGITS BELOW ZERO. WAA WILL KEEP OVERNIGHT LOWS
RELATIVELY WARM THOUGH...GENERALLY HOLDING STEADY IN THE LOW TO MID
TEENS.
LATEST MODEL SUITE HAS COME INTO BETTER AGREEMENT REGARDING THE
TIMING AND EVOLUTION OF NEXT SHORTWAVE MOVING ACROSS THE REGION
EARLY SATURDAY MORNING. PV ANOMALY ITSELF IS RATHER NONDESCRIPT AND
THERE IS NO UPPER LEVEL JET SUPPORT WITH MAINLY CONFLUENT FLOW ALOFT
OVER THE EASTERN HALF OF THE COUNTRY. THERE WILL BE A DECENT BAND OF
SYSTEM RELATIVE ISENTROPIC ASCENT AHEAD OF THE WAVE THOUGH. MOISTURE
WILL BE LIMITED BUT WE COULD SQUEEZE OUT SOME LIGHT SNOW
ACCUMULATIONS OF 1-2 INCHES BY MIDDAY SATURDAY. A SECOND AND
SLIGHTLY MORE IMPRESSIVE VORT MAX WILL THEN MOVE ACROSS THE GREAT
LAKES SATURDAY NIGHT. DYNAMICS ARE MUCH BETTER BUT BEST QG OMEGA
LOOKS TO PASS MAINLY NORTH OF HERE. COULD BE SOME LAKE ENHANCEMENT
BUT INVERSION HEIGHTS LOOK RELATIVELY LOW AND 850MB TEMPS ARE NOT
NEARLY AS COLD AS THURSDAYS EVENT. WILL CONTINUE WITH LOW CHANCE
POPS MAINLY ACROSS THE NORTH. LOOKS LIKE WE WILL GET ONE QUIET
WEATHER DAY ON SUNDAY BEFORE YET ANOTHER CLIPPER SYSTEM MOVES ACROSS
THE REGION ON MONDAY. 00Z GFS AND ECMWF KEEP MOST OF THE PRECIP
NORTH OF HERE BUT TRACK ERRORS THIS FAR OUT ARE ALMOST CERTAIN WITH
FAST NORTHWEST FLOW AND A PARADE OF LOW AMPLITUDE WAVES. WILL
MAINTAIN LOW CHANCE POPS YET AGAIN. PTYPES MAY ACTUALLY BE RAIN WITH
THIS EVENT THOUGH. TEMPS WILL GRADUALLY MODERATE THROUGH EARLY NEXT
WEEK WITH WAA LIKELY PUSHING HIGHS TO 40F BY MONDAY. OVERNIGHT LOWS
WILL UNDERGO A SIMILAR MODERATING TREND WITH VALUES GENERALLY IN THE
UPPER TEENS TO MID 20S...SLIGHTLY ABOVE NORMAL FOR EARLY
FEBRUARY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST THURSDAY FOR
LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...AGD
UPDATE...FISHER
AVIATION...NG
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1033 AM EST WED JAN 30 2013
.UPDATE...
QUICK UPDATE SENT TO ADD IN MENTION OF DRIZZLE IN NW AREAS AS
INCREASING LL LIFT AND NEARLY SATURATED BOUNDARY LAYER AREA
RESULTING IN AREAS OF DRIZZLE EXPANDING ACROSS THE NW QUARTER TO
HALF OF THE AREA. THINK THIS WILL BE SHORT LIVED AS COLD FRONT
APPROACHES FROM THE SW WITH DEEPER FORCING AND MSTR. BROKEN LINE
OF SHOWERS ACCOMPANIES THE FRONT WITH HRRR RUNS OVER THE PAST
COUPLE OF HOURS SHOWING AN EXPANDING AREA OF SHOWERS WITH GUSTY
WINDS (30 TO 35 KTS). FOR THE TIME BEING LIKELY POPS INHERITED
FROM OVERNIGHT FORECAST WILL WORK. MAY NEED AN ADDITIONAL UPDATE
IN A FEW HOURS IF COVERAGE DOES EXPAND AS HINTED AT. CHANGE OVER
TIMING ALSO LOOKS REASONABLE AT THIS STATE WITH FAR W/NW AREAS
SEEING A MIX OR FULL SWITCH IN THE 22Z TO 01Z TIME FRAME AND THEN
MARCHING EAST TO THE IN/OH STATE LINE IN THE 00-03Z WINDOW.
&&
.PREV DISCUSSION... /ISSUED 409 AM EST WED JAN 30 2013/
SHORT TERM...
PREFNTL CONV LINE CONTS TO ACCELERATE EWD EARLY THIS MORNING IN
RESPONSE TO UPSTREAM SW TROUGH EJECTING NEWD OUT OF KS. PRIMARY CDFNT
STILL LAGS APPRECIABLY WWD AN ANCHORED TO SFC CYCLONE OVR NRN IL.
00Z GUIDANCE TAKEN AS A WHOLE MOSTLY AGREEABLE SHRT TERM W/CONTD
NEWD EJECTING OF MAIN UPR TROUGH AND EWD DRIVING WEDGE OF ARCTIC AIR
TONIGHT. WILL DELAY CDFNT PROGRESSION SLIGHTLY FM PRIOR FCST PER
UPSTREAM TRENDS AND NR TERM RUC/HRRR GUIDANCE. THIS ALSO
NECESSITATES A UPWARD BUMP/EXPANSION IN POPS NW HALF THIS AFTN FOR
COMBINATION OF REDVLPG SHRA ALG SFC BNDRY AND MID LVL DEFORMATION
ZONE CLIPPING NWRN AREAS LT. OTRWS RAPID DEEPENING OF LL CAA WING
WILL CHG THINGS OVR RAPIDLY W-E THIS EVENING HWVR PALTRY SNOW AMTS
XPCD...INCH OR LESS.
LL THERMAL TROUGH BLDS ACRS THE LAKES LTR TONIGHT AND MAXIMIZES INTO
FRI. WHILE INITIAL SHRT FETCH WRLY FLW TRAJECTORY LIMITING
OVERNIGHT...SECONDARY SW TROUGH DROPPING RAPIDLY SEWD OUT OF AB AND
ATTENDANT MID LVL MSTR PLUME SHLD SEED A PD OF ENHANCED LK EFFECT LT
THU AFTN THOUGH FRI AM ESP IN CONTEXT OF ADDNL LL VEERING AND MUCH
IMPROVED FETCH. PRIOR DELINEATION OF HIGHEST BOUND POPS DEEMED CLOSE
BUT DID ERODE SRN EXTENT PER LATEST CONSENSUS.
LONG TERM...FRIDAY THROUGH TUESDAY
LAKE EFFECT WILL BE TAPERING OFF DURING THE DAY FRIDAY. STOUT
SUBSIDENCE INVERSION WILL DEVELOP BY FRIDAY AFTERNOON IN THE WAKE OF
DEPARTING SHORTWAVE. MEANWHILE...LOW LEVEL WINDS WILL BACK TO THE
SOUTHWEST AS RIDGE AXIS QUICKLY SHIFTS EAST OF HERE. THESE TWO
PROCESSES WILL CAUSE LAKE EFFECT BANDS TO SHIFT NORTH AND WEAKEN AS
THE DAY PROGRESSES. THIS WILL TAKE SOME TIME THOUGH AND WITH
CONVECTIVE DEPTHS STILL AROUND 7 KFT AND WIND DIRECTION STILL AROUND
290 BY LATE FRIDAY MORNING...ADDITIONAL ACCUMULATIONS OF AROUND AN
INCH ARE POSSIBLE MAINLY IN BERRIEN AND CASS COUNTIES BETWEEN 12Z
AND 18Z. MAIN STORY FOR THE REST OF THE CWA WILL BE VERY COLD TEMPS.
THERMAL TROUGH WILL BE MOVING OVERHEAD FRIDAY MORNING WITH 925MB
TEMPS AROUND -18C. THERMAL PROFILES WILL START TO REBOUND BY LATE
FRIDAY WITH DEVELOPING SOUTHWEST FLOW BUT THIS WILL LIKELY BE TOO
LITTLE TOO LATE TO GET HIGHS OUT OF THE MID TO UPPER TEENS. DECENT
GRADIENT WILL ALSO SUPPORT WINDS OF 10-20 MPH...MAKING IT FEEL LIKE
THE SINGLE DIGITS BELOW ZERO. WAA WILL KEEP OVERNIGHT LOWS
RELATIVELY WARM THOUGH...GENERALLY HOLDING STEADY IN THE LOW TO MID
TEENS.
LATEST MODEL SUITE HAS COME INTO BETTER AGREEMENT REGARDING THE
TIMING AND EVOLUTION OF NEXT SHORTWAVE MOVING ACROSS THE REGION
EARLY SATURDAY MORNING. PV ANOMALY ITSELF IS RATHER NONDESCRIPT AND
THERE IS NO UPPER LEVEL JET SUPPORT WITH MAINLY CONFLUENT FLOW ALOFT
OVER THE EASTERN HALF OF THE COUNTRY. THERE WILL BE A DECENT BAND OF
SYSTEM RELATIVE ISENTROPIC ASCENT AHEAD OF THE WAVE THOUGH. MOISTURE
WILL BE LIMITED BUT WE COULD SQUEEZE OUT SOME LIGHT SNOW
ACCUMULATIONS OF 1-2 INCHES BY MIDDAY SATURDAY. A SECOND AND
SLIGHTLY MORE IMPRESSIVE VORT MAX WILL THEN MOVE ACROSS THE GREAT
LAKES SATURDAY NIGHT. DYNAMICS ARE MUCH BETTER BUT BEST QG OMEGA
LOOKS TO PASS MAINLY NORTH OF HERE. COULD BE SOME LAKE ENHANCEMENT
BUT INVERSION HEIGHTS LOOK RELATIVELY LOW AND 850MB TEMPS ARE NOT
NEARLY AS COLD AS THURSDAYS EVENT. WILL CONTINUE WITH LOW CHANCE
POPS MAINLY ACROSS THE NORTH. LOOKS LIKE WE WILL GET ONE QUIET
WEATHER DAY ON SUNDAY BEFORE YET ANOTHER CLIPPER SYSTEM MOVES ACROSS
THE REGION ON MONDAY. 00Z GFS AND ECMWF KEEP MOST OF THE PRECIP
NORTH OF HERE BUT TRACK ERRORS THIS FAR OUT ARE ALMOST CERTAIN WITH
FAST NORTHWEST FLOW AND A PARADE OF LOW AMPLITUDE WAVES. WILL
MAINTAIN LOW CHANCE POPS YET AGAIN. PTYPES MAY ACTUALLY BE RAIN WITH
THIS EVENT THOUGH. TEMPS WILL GRADUALLY MODERATE THROUGH EARLY NEXT
WEEK WITH WAA LIKELY PUSHING HIGHS TO 40F BY MONDAY. OVERNIGHT LOWS
WILL UNDERGO A SIMILAR MODERATING TREND WITH VALUES GENERALLY IN THE
UPPER TEENS TO MID 20S...SLIGHTLY ABOVE NORMAL FOR EARLY FEBRUARY.&&
AVIATION...
WIDESPREAD LT-MOD STRATIFORM RAIN DEFINED BY VFR CIGS AND POCKETS
OF MVFR VSBYS CONTS WITHIN BROAD SWRLY FLW AND CONTD LL THETA-E
ADVTN/MSTR TRANSPORT AHD OF UPSTREAM SW TROUGH OVR NW MO AND
DOUBLE BARREL SFC LOW XTNDG FM SE MI INTO SRN MO. HWVR HEAVIER
RAIN WILL CONT TO SHUNT QUICKLY NEWD THROUGH DAWN IN RESPONSE TO
WKNG LLJ. LEADING EDGE OF UPSTREAM CAA WING WORKING INTO CNTRL IL
ATTM AND A BIT SLWR EVEN THAN 00Z GUIDANCE HAD INDICATED AND WILL
BACK ARRIVAL OF IFR/LIFR CONDS INTO THE TERMINALS A BIT LATER W/12Z
ISSUANCE. OTRWS STG CAA WING WILL ARRIVE TWD 00Z W/STG WRLY WINDS
DVLPG W/SFC GUSTS AOA 30KTS THROUGH LT EVENING XPCD. WILL ADDRESS
THIS AND PD OF ACCUMULATING SNOW AT KSBN THIS EVENING W/12Z
ISSUANCE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST THURSDAY FOR
LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...AGD
AVIATION...T
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
952 AM EST WED JAN 30 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 420 AM EST WED JAN 30 2013
STRONG SYSTEM WILL BE PASSING THROUGH THE AREA THROUGH TONIGHT.
SHOWERS IN THE WAKE OF THUNDERSTORMS WILL CONTINUE THROUGH MID
MORNING...WITH ADDITIONAL SHOWERS POSSIBLY DEVELOPING LATER TODAY.
ARCTIC AIR WILL BEGIN RUSHING INTO THE AREA LATE THIS
AFTERNOON...AND ANY REMAINING PRECIPITATION WILL CHANGE QUICKLY
OVER TO SNOW THIS EVENING. ANOTHER UPPER LEVEL WAVE WILL PUSH
THROUGH THE AREA TOMORROW AFTERNOON AND EVENING...PERHAPS BRINGING
LIGHT SNOW SHOWERS TO THE AREA...FOLLOWED BY ANOTHER DISTURBANCE
WITH THE POTENTIAL FOR SNOW FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 943 AM EST WED JAN 30 2013
RAIN ASSOCIATED WITH OVERNIGHT STORMS HAS MOVED OUT OF THE AREA.
RADAR MOSAIC SHOWS A LINE OF SHOWERS OVER CENTRAL ILLINOIS AND
SHORT TERM MODELS SHOW THIS LINE MOVING INTO THE WESTERN COUNTIES
AROUND 17-18Z AND ACROSS THE AREA FROM THERE. ALSO SOME POTENTIAL
FOR A FEW SHOWERS TO POP UP AHEAD OF THIS LINE AND MOVE NORTHEAST
TO THE AREA FROM SOUTHERN ILLINOIS/WESTERN KENTUCKY. HAVE ADDED
SOME DETAIL TO THE NEXT FEW HOURS COMPLETELY REMOVING RAIN FOR
MOST OF THE AREA AND THEN BRING BACK CHANCES STARTING AT 17Z AND
RAMPING UP FROM THERE. TIMING OF CHANGEOVER TO SNOW STILL LOOKS
LIKE IT COULD HAPPEN IN THE NORTHWEST AFTER 21Z BUT SHOULD NOT
REACH THE REST OF THE AREA UNTIL AFTER 0Z. WINDS THIS MORNING ARE
LIGHTER THAN FORECAST BUT SOUNDINGS STILL HAVE THEM INCREASING
QUITE A BIT THIS AFTERNOON WITH GUSTS AROUND 40 MPH EXPECTED THIS
AFTERNOON. WITH THE SLIGHTLY SLOWER ARRIVAL OF THE COLD AIR
BEHIND THE FINAL COLD FRONT /STILL OVER WESTERN ILLINOIS/ AND LESS
RAIN AROUND THE NEXT FEW HOURS EXPECT TEMPERATURES TO RISE IN THE
CENTRAL AND EASTERN COUNTIES AND REMAIN STEADY IN THE WEST UNTIL
MID AFTERNOON WHEN THEY SHOULD START TO PLUMMET IN THE WEST AND
THIS WILL OVERSPREAD THE AREA THROUGH THE EVENING.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 420 AM EST WED JAN 30 2013
AS THE SECOND COLD FRONT PASSES THE AREA EARLY THIS
EVENING...EXPECT THAT ALL PRECIP WILL CHANGE TO SNOW BY AROUND
02-03Z. PRECIP SHOULD BE SNOW ACROSS THE WEST BY 00Z...WITH
CHANGEOVER PROGRESSING RAPIDLY ACROSS THE AREA. MOST PRECIP SHOULD
BE DONE BY 06Z.
BRIEF LULL IN PRECIP CHANCES EXPECTED LATE TONIGHT INTO EARLY
THURSDAY. ADDITIONAL WAVE WILL PUSH THROUGH THE AREA LATE THURSDAY
INTO THURSDAY NIGHT...AND MODELS ARE A BIT MORE BULLISH ON THIS
WAVE THAN PREVIOUSLY. ADDITIONALLY...FORCING IS IMPROVED...WITH
DECENT Q VECTOR CONVERGENCE AND EVEN SOME GOOD FRONTOGENESIS AND
MODERATE EPV. WILL LEAN TO HIGHER END OF THE GUIDANCE ENVELOPE.
THIS MAY PRODUCE LIGHT ACCUMULATIONS OF AN INCH OR LESS ACROSS
PORTIONS OF THE AREA.
FINALLY...ADDITIONAL WAVE WILL APPROACH ON FRIDAY NIGHT...LOW
CHANCE POPS APPEAR REASONABLE.
WINDS TONIGHT POST FRONT MAY GUST TO AROUND 30-35KT AT TIMES...AS
ACCORDING TO BUFKIT SOUNDINGS AND LOW LEVEL WIND PROGS OFF MODELS.
AGAIN THIS IS BELOW ADVISORY CRITERIA.
ON TEMPS...CONSENSUS APPEARED REASONABLE AND ONLY A FEW MINOR
TWEAKS REQUIRED. DID BUMP TEMPS DOWN SLIGHTLY THROUGHOUT WITH COLD
ADVECTION ONGOING UNTIL LATE IN THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 305 AM EST WED JAN 30 2013
MODELS KEEP A BROAD UPPER TROUGH ACROSS EASTERN CANADA...GREAT LAKES
AND NORTHEAST U.S. THROUGH THE PERIOD. THERE ARE A COUPLE OF WEAK
UPPER DISTURBANCES THAT WILL ROTATE ACROSS OUR AREA WITH ONE
OCCURRING AROUND SATURDAY...ANOTHER ONE LATE MONDAY AND THE EURO HAS
ONE OCCURRING LATE TUESDAY...WHICH THE GFS DOES NOT.
CONFIDENCE OF TUESDAY SYSTEM IS VERY LOW...HOWEVER ALL MODELS HAVE
TRENDED WITH HIGHER POPS THEN...SO WILL ADD SLIGHT CHANCE OF SNOW
SHOWERS DAY 7. OTHERWISE ALL BLEND POPS SEEM REASONABLE IN MOST
OTHER CASES.
AS FAR AS TEMPERATURES ARE CONCERNED MODELS HAVE TRENDED A LITTLE
COLDER OVER THE WEEKEND AND TUESDAY. IN MOST CASES WENT WITH A
BLEND OF ALL BLEND AND CONSALL NUMBERS.
&&
.AVIATION /DISCUSSION FOR THE 301500Z TAF ISSUANCE/...
ISSUED AT 940 AM EST TUE JAN 29 2013
WIDESPREAD RAIN HAS MOVED EAST OF THE TERMINALS THIS MORNING WITH
IFR AND LOWER CONDITIONS PERSISTING ACROSS THE REGION. MADE
ADJUSTMENTS TO WIND SPEED/DIRECTION BASED ON CURRENT OBS. ALSO AM
LESS OPTIMISTIC IN CEILING IMPROVEMENT THROUGH EARLY AFTERNOON WITH
CEILINGS BELOW 1000FT EXTENDING BACK INTO EASTERN ILLINOIS. MOST
RECENT HRRR GUIDANCE AND OBS AGREE ON SCATTERED SHOWERS EXPANDING
BACK INTO THE REGION BY EARLY AFTERNOON AS THE COLD FRONT
APPROACHES. WIND GUSTS WILL INCREASE THROUGH THE AFTERNOON ALONG AND
BEHIND THE FRONTAL PASSAGE.
12Z DISCUSSION FOLLOWS.
MOSTLY MVFR CEILINGS THROUGH THE PERIOD WITH GUSTY WINDS THIS
AFTERNOON AND TONIGHT.
LOW PRESSURE OVER NORTHEAST ILLINOIS WILL TRACK NORTHEAST ACROSS THE
GREAT LAKES AS A COLD FRONT MOVES ACROSS CENTRAL INDIANA LATER
TODAY. AREA OF RAIN CURRENTLY ACROSS CENTRAL INDIANA WILL MOVE ON
TO THE EAST. HOWEVER RAPID REFRESH AND OTHER MODELS INDICATE
SCATTERED SHOWERS MOVING BACK IN ACROSS TAF SITES BY MIDDAY AND WITH
PRECIPITATION CHANGING TO LIGHT SNOW SHOWERS OR FLURRIES BY
EVENING.
WITH THE EXCEPTION OF KLAF CEILINGS CURRENTLY AT OR ABOVE 3
THOUSAND. BUT UPSTREAM THEY ARE MUCH LOWER AND THESE LOWER CEILINGS
WILL SPREAD ACROSS TAF SITES LATER TODAY. AT TIME BELIEVE CEILINGS
SHOULD AVERAGE ABOUT 15 HUNDRED FEET BY THIS AFTERNOON AND EARLY
TONIGHT WITH SOME IMPROVEMENT LATE TONIGHT.
WINDS HAVE TEMPORARILY BECOME LIGHT THIS MORNING BUT WILL PICK UP
AGAIN BY THIS AFTERNOON AFTER COLD FRONT MOVES THROUGH AND WITH SOME
AREAS GUSTING UP TO 30 KNOTS LATE TODAY AND TONIGHT..
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM....JH
AVIATION...JH/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
942 AM EST WED JAN 30 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 420 AM EST WED JAN 30 2013
STRONG SYSTEM WILL BE PASSING THROUGH THE AREA THROUGH TONIGHT.
SHOWERS IN THE WAKE OF THUNDERSTORMS WILL CONTINUE THROUGH MID
MORNING...WITH ADDITIONAL SHOWERS POSSIBLY DEVELOPING LATER TODAY.
ARCTIC AIR WILL BEGIN RUSHING INTO THE AREA LATE THIS
AFTERNOON...AND ANY REMAINING PRECIPITATION WILL CHANGE QUICKLY
OVER TO SNOW THIS EVENING. ANOTHER UPPER LEVEL WAVE WILL PUSH
THROUGH THE AREA TOMORROW AFTERNOON AND EVENING...PERHAPS BRINGING
LIGHT SNOW SHOWERS TO THE AREA...FOLLOWED BY ANOTHER DISTURBANCE
WITH THE POTENTIAL FOR SNOW FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 420 AM EST WED JAN 30 2013
STORMS ARE EXITING THE FORECAST AREA AT THIS TIME...WITH ONLY
STRATIFORM RAIN IN THE WAKE OF THE STORMS ACROSS THE AREA. EXPECT
A LULL PERHAPS LATER THIS MORNING WITH THE POTENTIAL FOR
ADDITIONAL SHOWERS LATER THIS AFTERNOON AS THE UPPER WAVE
APPROACHES. SECONDARY COLD FRONT WILL PASS STARTING LATE THIS
AFTERNOON/EARLY EVENING.
BUFKIT SOUNDINGS HAVE BACKED OFF ON WIND GUSTS QUITE A BIT...AND
NOW NOT EXPECTING ADVISORY CRITERIA GUSTS...MORE LIKE 30 MPH.
GUSTS MAY BE STRONGER TONIGHT POST FRONTAL.
FAST MOVING NATURE OF STORMS CONTRIBUTED TO MUCH LESS RAINFALL
THAN ORIGINALLY FEARED...WITH AMOUNTS THROUGH 12Z LIKELY TO BE
AROUND AN INCH WITH ISOLATED HIGHER AMOUNTS. THUS...WILL CANCEL
THE FLOOD WATCH. RIVERS MAY STILL GO INTO FLOOD...BUT WIDESPREAD
AREAL FLOOD THREAT HAS DIMINISHED SIGNIFICANTLY.
ON TEMPS...RELIED HEAVILY ON NAM WETBULB TEMP PROGS...AS PRECIP
WILL BE ONGOING AT TIMES THROUGHOUT THE DAY AND INITIAL PROGS
COMPARED FAVORABLY TO OBS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 420 AM EST WED JAN 30 2013
AS THE SECOND COLD FRONT PASSES THE AREA EARLY THIS
EVENING...EXPECT THAT ALL PRECIP WILL CHANGE TO SNOW BY AROUND
02-03Z. PRECIP SHOULD BE SNOW ACROSS THE WEST BY 00Z...WITH
CHANGEOVER PROGRESSING RAPIDLY ACROSS THE AREA. MOST PRECIP SHOULD
BE DONE BY 06Z.
BRIEF LULL IN PRECIP CHANCES EXPECTED LATE TONIGHT INTO EARLY
THURSDAY. ADDITIONAL WAVE WILL PUSH THROUGH THE AREA LATE THURSDAY
INTO THURSDAY NIGHT...AND MODELS ARE A BIT MORE BULLISH ON THIS
WAVE THAN PREVIOUSLY. ADDITIONALLY...FORCING IS IMPROVED...WITH
DECENT Q VECTOR CONVERGENCE AND EVEN SOME GOOD FRONTOGENESIS AND
MODERATE EPV. WILL LEAN TO HIGHER END OF THE GUIDANCE ENVELOPE.
THIS MAY PRODUCE LIGHT ACCUMULATIONS OF AN INCH OR LESS ACROSS
PORTIONS OF THE AREA.
FINALLY...ADDITIONAL WAVE WILL APPROACH ON FRIDAY NIGHT...LOW
CHANCE POPS APPEAR REASONABLE.
WINDS TONIGHT POST FRONT MAY GUST TO AROUND 30-35KT AT TIMES...AS
ACCORDING TO BUFKIT SOUNDINGS AND LOW LEVEL WIND PROGS OFF MODELS.
AGAIN THIS IS BELOW ADVISORY CRITERIA.
ON TEMPS...CONSENSUS APPEARED REASONABLE AND ONLY A FEW MINOR
TWEAKS REQUIRED. DID BUMP TEMPS DOWN SLIGHTLY THROUGHOUT WITH COLD
ADVECTION ONGOING UNTIL LATE IN THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 305 AM EST WED JAN 30 2013
MODELS KEEP A BROAD UPPER TROUGH ACROSS EASTERN CANADA...GREAT LAKES
AND NORTHEAST U.S. THROUGH THE PERIOD. THERE ARE A COUPLE OF WEAK
UPPER DISTURBANCES THAT WILL ROTATE ACROSS OUR AREA WITH ONE
OCCURRING AROUND SATURDAY...ANOTHER ONE LATE MONDAY AND THE EURO HAS
ONE OCCURRING LATE TUESDAY...WHICH THE GFS DOES NOT.
CONFIDENCE OF TUESDAY SYSTEM IS VERY LOW...HOWEVER ALL MODELS HAVE
TRENDED WITH HIGHER POPS THEN...SO WILL ADD SLIGHT CHANCE OF SNOW
SHOWERS DAY 7. OTHERWISE ALL BLEND POPS SEEM REASONABLE IN MOST
OTHER CASES.
AS FAR AS TEMPERATURES ARE CONCERNED MODELS HAVE TRENDED A LITTLE
COLDER OVER THE WEEKEND AND TUESDAY. IN MOST CASES WENT WITH A
BLEND OF ALL BLEND AND CONSALL NUMBERS.
&&
.AVIATION /DISCUSSION FOR THE 301500Z TAF ISSUANCE/...
ISSUED AT 940 AM EST TUE JAN 29 2013
WIDESPREAD RAIN HAS MOVED EAST OF THE TERMINALS THIS MORNING WITH
IFR AND LOWER CONDITIONS PERSISTING ACROSS THE REGION. MADE
ADJUSTMENTS TO WIND SPEED/DIRECTION BASED ON CURRENT OBS. ALSO AM
LESS OPTIMISTIC IN CEILING IMPROVEMENT THROUGH EARLY AFTERNOON WITH
CEILINGS BELOW 1000FT EXTENDING BACK INTO EASTERN ILLINOIS. MOST
RECENT HRRR GUIDANCE AND OBS AGREE ON SCATTERED SHOWERS EXPANDING
BACK INTO THE REGION BY EARLY AFTERNOON AS THE COLD FRONT
APPROACHES. WIND GUSTS WILL INCREASE THROUGH THE AFTERNOON ALONG AND
BEHIND THE FRONTAL PASSAGE.
12Z DISCUSSION FOLLOWS.
MOSTLY MVFR CEILINGS THROUGH THE PERIOD WITH GUSTY WINDS THIS
AFTERNOON AND TONIGHT.
LOW PRESSURE OVER NORTHEAST ILLINOIS WILL TRACK NORTHEAST ACROSS THE
GREAT LAKES AS A COLD FRONT MOVES ACROSS CENTRAL INDIANA LATER
TODAY. AREA OF RAIN CURRENTLY ACROSS CENTRAL INDIANA WILL MOVE ON
TO THE EAST. HOWEVER RAPID REFRESH AND OTHER MODELS INDICATE
SCATTERED SHOWERS MOVING BACK IN ACROSS TAF SITES BY MIDDAY AND WITH
PRECIPITATION CHANGING TO LIGHT SNOW SHOWERS OR FLURRIES BY
EVENING.
WITH THE EXCEPTION OF KLAF CEILINGS CURRENTLY AT OR ABOVE 3
THOUSAND. BUT UPSTREAM THEY ARE MUCH LOWER AND THESE LOWER CEILINGS
WILL SPREAD ACROSS TAF SITES LATER TODAY. AT TIME BELIEVE CEILINGS
SHOULD AVERAGE ABOUT 15 HUNDRED FEET BY THIS AFTERNOON AND EARLY
TONIGHT WITH SOME IMPROVEMENT LATE TONIGHT.
WINDS HAVE TEMPORARILY BECOME LIGHT THIS MORNING BUT WILL PICK UP
AGAIN BY THIS AFTERNOON AFTER COLD FRONT MOVES THROUGH AND WITH SOME
AREAS GUSTING UP TO 30 KNOTS LATE TODAY AND TONIGHT..
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....JH
AVIATION...JH/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
305 AM EST TUE JAN 29 2013
.UPDATE...
LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 PM EST TUE JAN 29 2013
NUMEROUS WEATHER HAZARDS WILL ACCOMPANY AN EXTREMELY POTENT SYSTEM
IMPACTING THE REGION THROUGH TOMORROW. VERY UNSEASONABLY WARM AND
MOIST CONDITIONS WILL BE IN PLACE THROUGH TONIGHT. AHEAD OF A
STRONG COLD FRONT SWEEPING THROUGH THE REGION...THE POTENTIAL WILL
EXIST FOR THUNDERSTORMS...HEAVY RAINFALL...FLOODING AND DAMAGING
WINDS. POTENTIAL FOR STRONG WINDS WILL CONTINUE BEHIND THE FRONTAL
BOUNDARY ON WEDNESDAY...AND FLOODING MAY LAST FOR SEVERAL DAYS OR
MORE.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 942 PM EST TUE JAN 29 2013
UPDATE...
LINE OF STRONG TO SEVERE THUNDERSTORMS IS WELL OUT AHEAD OF THE
COLD FRONT AND CURRENTLY PUSHING EASTWARD THROUGH ILLINOIS AND
WESTERN KENTUCKY. TEMPS ACROSS CENTRAL INDIANA HAVE BEEN SLOWLY
RISING A FEW DEGREES OVER THE LAST FEW HOURS AS STRONG LOW LEVEL
JET ADVECTS WARM AIR AHEAD OF IT. SO...LOSS OF DIURNAL HEATING
HAS HAD LITTLE AFFECT ON ENVIRONMENT. INSTABILITY LOOKS MOST
FAVORABLE FOR SEVERE STORMS ACROSS THE SOUTHERN PORTIONS OF
FORECAST AREA PER LATEST LAPS ANALYSES.
PREVIOUS DISCUSSION... FOCUS OF THE NEAR TERM REMAINS ON SEVERE
WEATHER CHANCES AS WELL AS POSSIBLE HEAVY RAINFALL/FLOODING
POSSIBILITIES TONIGHT. THE PERIOD BEGINS WITH GOOD SHORT TERM
MODEL AGREEMENT AS TO THE LOCATION OF KEY FEATURES THAT MAY BRING
POSSIBLE SEVERE TO PORTIONS OF THE FORECAST AREA TONIGHT. AT
00Z/WED...THE LOW PRESSURE CENTER IS PROGGED TO BE OVER CENTRAL
MISSOURI...WITH ONGOING CONVECTION POSSIBLY ALREADY IN THE FORM OF
A SQUALL LINE ALONG A STRONG COLD FRONT STRETCHED FROM NORTHWEST
ILLINOIS...DOWN THROUGH CENTRAL MISSOURI...INTO EASTERN
OKLAHOMA/WESTERN ARKANSAS.
THERE DOES APPEAR TO BE SOME DIFFERENCES IN SPEED/TIMING OF THE
FRONT INTO THE FORECAST AREA...WITH THE HRRR AND RAP INTO THE AREA A
BIT QUICKER THE THE NAM AND GFS. PERSONAL EXPERIENCE HAS SHOWN THAT
THESE COLD FRONT/SQUALL LINE FEATURES TEND TO COME IN A BIT QUICKER
THAN SOMETIMES EXPECTED. THEREFORE...DECIDED TO TREND TOWARD THE
HRRR/RUC SOLNS.
AS WAS MENTIONED IN PREVIOUS DISCUSSIONS...DYNAMICS WILL NOT BE AN
ISSUE WITH THIS SYSTEM AS THE FRONT APPROACHES. A LOW LEVEL JET AOA
80 KTS AT 850 MB IS EXPECTED TO DEVELOP OUT AHEAD OF THE FRONT THIS
EVENING AND WILL TRANSLATE INTO OUR AREA TONIGHT. WITH 50 KT WINDS
LOCATED APPROXIMATELY 1000-1500 FEET ABOVE THE SURFACE
TONIGHT...DAMAGING WINDS MAY BECOME A REAL THREAT WITH ANY STORMS
THAT ARE ABLE TO REMAIN ORGANIZED AS THEY PUSH INTO THE FORECAST
AREA. ONE LIMITING FACTOR FOR CONVECTION REMAINING ORGANIZED INTO
THE OVERNIGHT HOURS IS INSTABILITY. SFC-BASED CAPE LOOKS TO BE IN
THE UNDER 200 J/KG RANGE...WHILE MUCAPE GIVES SLIGHTLY HIGHER
VALUES OF 200-400 J/KG AS THE FRONT MOVES INTO THE AREA. WITH THE
STRONG DYNAMICS AVAILABLE...WILL CONTINUE DAMAGING WINDS REFERENCE
IN THE GRIDS. ALSO KEEP IN MIND THAT WITH AMPLE LOW LEVEL
SHEAR...0-1 HELICITIES AOA 400-500 M2/S2...AN ISOLATED TORNADO
CANNOT BE RULED OUT.
THE BEST TIMING FOR SEVERE LOOKS TO START AT APPROXIMATELY 04-05Z
ACROSS WESTERN PORTIONS OF THE FORECAST AREA...TO ABOUT 10-11Z OVER
THE EAST. JUST ONE OTHER NOTE TO MENTION...THE HRRR ILLUSTRATES A
LINE OF CONVECTION DEVELOPING OUT AHEAD OF THE MAIN SQUALL LINE. TO
A LESSER EXTENT...THE RAP ALSO DEPICTS A SIMILAR SCENARIO. WHILE
THIS FORECAST HAS TAKEN THIS INTO CONSIDERATION...IT COULD STILL
ALLOW FOR AN EARLIER ONSET THAN FORECAST.
HEAVY RAINFALL IS ALSO IN PLAY TONIGHT AS MOISTURE HAS CONTINUED TO
STREAM NORTH INTO THE AREA. A PACIFIC TROPICAL PLUME OF MOISTURE HAS
BEEN EVIDENT ALL DAY ON WATER VAPOR IMAGERY STREAMING NORTHWEST INTO
LOWER MISSOURI/MID MISSISSIPPI/OHIO RIVER VALLEY STATES. COUPLE THAT
WITH 60 DEGREE DEWPOINTS CURRENTLY ON THE SOUTHWESTERN DOORSTEP OF
THE FORECAST AREA. PWATS TONIGHT AHEAD OF THE FRONT LOOK TO REACH
UPWARDS OF 1.40-1.50 INCHES...YIELDING A PERCENT OF NORMAL OF AROUND
300 PERCENT. WOULD NOT BE SURPRISED TO SEE A WIDESPREAD 1 TO 1.5
INCH RAINFALL...WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 337 PM EST TUE JAN 29 2013
SHORT TERM PERIOD SEES A DIFFERENT SET OF CHALLENGES. ONE OF THE
INITIAL CHALLENGES WILL BE STRONG WINDS AFTER THE COLD FRONT SWEEPS
THROUGH THE AREA AND A DRY SLOT APPROACHES THE FORECAST AREA DURING
THE AFTERNOON HOURS. SUSTAINED WINDS AROUND 20-25 KTS...WITH THE
POSSIBILITY TO TAP 40 KT WINDS FROM APPROX 850 MB AS BOUNDARY LAYER
MIXES OUT. A WIND ADVISORY MAY BE NEED FOR A TIME IN THE LATE
MORNING TO EARLY EVENING HOURS ON WEDNESDAY.
ADDITIONALLY...SOME LIGHT SNOW SHOWERS MAY WRAP AROUND AND AFFECT
MAINLY NORTHERN PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT AS THE
UPPER TROUGH FINALLY PASSES THROUGH. NOT CURRENTLY EXPECTING MUCH IN
THE WAY OF ACCUMULATION.
ANOTHER UPPER TROUGH AND COLD FRONT PUSHES INTO THE THROUGH THE AREA
LATE THURSDAY INTO THURSDAY NIGHT...BRINGING AN ADDITIONAL CHANCE
FOR SNOW AND FALLING TEMPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 305 AM EST WED JAN 30 2013
MODELS KEEP A BROAD UPPER TROUGH ACROSS EASTERN CANADA...GREAT LAKES
AND NORTHEAST U.S. THROUGH THE PERIOD. THERE ARE A COUPLE OF WEAK
UPPER DISTURBANCES THAT WILL ROTATE ACROSS OUR AREA WITH ONE
OCCURRING AROUND SATURDAY...ANOTHER ONE LATE MONDAY AND THE EURO HAS
ONE OCCURRING LATE TUESDAY...WHICH THE GFS DOES NOT.
CONFIDENCE OF TUESDAY SYSTEM IS VERY LOW...HOWEVER ALL MODELS HAVE
TRENDED WITH HIGHER POPS THEN...SO WILL ADD SLIGHT CHANCE OF SNOW
SHOWERS DAY 7. OTHERWISE ALL BLEND POPS SEEM REASONABLE IN MOST
OTHER CASES.
AS FAR AS TEMPERATURES ARE CONCERNED MODELS HAVE TRENDED A LITTLE
COLDER OVER THE WEEKEND AND TUESDAY. IN MOST CASES WENT WITH A
BLEND OF ALL BLEND AND CONSALL NUMBERS.
&&
.AVIATION /DISCUSSION FOR THE 30/06Z TAF ISSUANCE/...
ISSUED AT 1055 PM EST TUE JAN 29 2013
SEVERE SQUALL LINE ACROSS EASTERN ILLINOIS AND SOUTHEASTERN MISSOURI
LATE THIS EVENING WILL BE NEAR IND AND BMG AROUND ISSUANCE
TIME...AND WITH TORNADO WATCH IN EFFECT FOR BMG...WILL GO WITH A
TEMPO 40 KNOT SUSTAINED AND 50 KNOT GUST THROUGH 09Z WITH OTHERWISE
SOUTHWWEST WINDS AROUND 20 KNOTS WITH GUSTS TO 35 KNOTS THE
REMAINDER OF THE NIGHT. WINDS WILL SHIFT TO SOUTHWEST AND WEST AND
THE SOLID RAINS SHOULD END BEHIND THE COLD FRONT THAT SHOULD MOVE
THROUGH AROUND 12Z AT HUF AND HUF AND 14Z AT IND AND BMG. WINDS
WHOULD STAY UP THROUGH THE ENTIRE TAF PERIOD BUT SLIGHTLY DECREASE
IN SPEED AT IND AFTER 06Z THURSDAY. BASED ON LIGHTNING DATA...WILL
GO WITH TEMPO THUNDERSTORMS AT IND AND BMG THROUGH 09Z AND THE OTHER
SITES ONLY UNTIL 07Z. COULD SEE SOME MORE SHOWERS THIS AFTERNOON
POSSIBLY MIXED WITH SNOW LATE...BUT COVERAGE APPEARS TOO LOW TO
MENTION IN TAFS AT LEAST AT THIS TIME. MVFR CONDITIONS...EXCEPT IFR
IN THUNDERSTORMS TO BECOME VFR AFTER 15Z PER MODEL TIME SECTIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH WEDNESDAY MORNING FOR INZ021-028>031-035>049-
051>057-060>065-067>072.
&&
$$
SYNOPSIS...MRD
NEAR TERM...MRD/TDUD
SHORT TERM...MRD
LONG TERM....JH
AVIATION...MK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1147 PM CST TUE JAN 29 2013
.UPDATE...
ADDED 06Z TAF DISCUSSION.
THERE WILL BE LITTLE CHANGE IN THINKING WITH A TOKEN EVENING UPDATE
TO FIT CURRENT OBS. WAS ORIGINALLY THINKING THAT FORECAST AMOUNTS
MAY BE TOO HIGH ON NW FRINGE OF FORECAST PRECIP SHIELD...HOWEVER 00Z
NAM IS NOW PLACING HEAVIEST SNOWFALL AXIS SW-NE RIGHT THROUGH DES
MOINES. FAR NW FRINGE OF ADVISORY MAY BE OVERDONE...BUT STILL LOOKS
LIKE FORT DODGE AND MASON CITY AREAS MAY BE BRUSHED...ESPECIALLY SRN
PORTIONS OF THOSE COUNTIES. NO CHANGES IN HEADLINES WHICH
CONFIDENCE IN ANY PARTICULAR SOLUTION NOT GREAT ENOUGH TO CHANGE
THINGS. LOOKED TO THE RAP FOR GUIDANCE BUT PAST SEVERAL RUNS ARE
LITTLE HELP AS THEY HAVE BEEN CONSISTENTLY TOO AGGRESSIVE IN TIMING
AND STRENGTH WITH PRECIP ONSET INTO IA.
00Z H85 ANALYSIS SHOWS STRONG WARM/MOIST ADVECTION INTO ST
JOESPH/KC METRO AREAS AND TOPS ARE COOLING THERE SO SEE LITTLE
REASON TO DOUBT PREVIOUS THINKING WITH PRECIP BLOSSOMING SHORTLY AND
THAT APPEARS TO BE THE CASE. RADAR ECHOES ARE STRENGTHENING AND
VIRGA DONUT SHRINKING. DUAL POL RADAR PRODUCTS SHOW RAIN/SNOW
LINE ROUGHLY ALONG BEDFORD-OSCEOLA-NEWTON LINE SO SHOULD SEE ONLY
SNOW TO N AND W OF THESE AREAS.
PREVIOUS 00Z UPDATE...ADJUSTED FORECAST AND HEADLINES TO NOT START
UNTIL 03Z BASED ON LATEST MODEL GUIDANCE AND OBSERVATIONAL TRENDS.
WILL OBVIOUSLY RE-EXAMINE FORECAST FURTHER AFTER 00Z MODELS COME IN
AND SYSTEM STARTS TO SHOW ITS HAND MORE UPSTREAM INTO NE AND KS.
ADDED 00Z TAF DISCUSSION.
&&
.SHORT TERM /TONIGHT/...
UPPER WAVE EVIDENT ON WATER VAPOR DIGGING ALONG THE US/MEXICO BORDER
AND STARTING TO LIFT NORTHEASTWARD INTO THE TEX PANHANDLE...TO
CONTINUE ITS CURRENT TRAJECTORY NORTHEASTWARD THROUGH THE CENTRAL
PLAINS AND INTO THE MID MISSISSIPPI VALLEY BY EARLY WEDNESDAY. THE
STATE BECOMES SANDWICHED BETWEEN COUPLED JET STREAKS ALOFT...WITH
STRONGEST FRONTOGENETICAL LIFT SHOWING UP ACROSS THE SOUTHEASTERN
HALF OF THE CWA LATE THIS EVENING INTO THE OVERNIGHT HOURS. TROWAL
FEATURE TO ROTATE EASTWARD THROUGH CENTRAL/SOUTHEASTERN CWA...WITH
INCREASING MOISTURE IN THE LOW/MID LEVELS. DRIER AIR WORKING ITS WAY
INTO THE NORTH SHOULD YIELD A SHARP CUTOFF IN THE SNOW FIELD TO THE
NORTHWEST...WITH THE NORTHWESTERN CUTOFF TO THE HEAVIER SNOW FROM
NEAR CORNING NORTHEASTWARD TO WAVERLY. HEAVIEST AMOUNTS EXPECTED
ACROSS THE FAR SOUTHEASTERN CWA...WHERE QPF WILL BE GREATER AND
COULD SEE SOME WEAK INSTABILITY ALOFT ENHANCE SNOWFALL RATES AT
TIMES LATE TONIGHT. OVERALL THREE TO FOUR INCHES OF SNOW EXPECTED
TO FALL ACROSS THE SOUTHEASTERN HALF OF THE CWA BY 12Z WEDNESDAY.
SFC PRES GRADIENT TO TIGHTEN ON THE BACKSIDE OF THIS SYSTEM...WITH
STRONG CAA. 925MB TO 850MB WINDS EXPECTED TO BE IN THE 30 TO 35KT
RANGE BY LATE TONIGHT...WITH THESE WINDS TRANSLATING TO THE SURFACE
WITH THE STRONG CAA. THEREFORE EXPECTING SUSTAINED WINDS IN THE 20
TO 30 MPH RANGE...WITH GUSTS TO 35 MPH OR HIGHER BY LATE TONIGHT
ACROSS THE AREA. THIS WILL LEAD TO CONSIDERABLE BLOWING SNOW IN OPEN
AREAS. ADDITIONALLY WITH THE RESIDUAL SURFACE MOISTURE AROUND...AND
POSSIBILITY OF HEAVY WET SNOW INITIALLY BEFORE THE DRIER AIR WORKS
INTO THE AREA RESULTING IN A LIGHTER FLUFFIER SNOW...SOME ICING MAY
OCCUR ON ROADWAYS...TREES BRANCHES...AND POWER LINES. THEREFORE WILL
CONTINUE THE WINTER HEADLINES AS THEY ARE FOR TONIGHT INTO WEDNESDAY
MORNING.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
RAPIDLY DEEPENING LOW PRESSURE WILL BE OVER CENTRAL ILLINOIS BY 12Z
AND WILL SHIFT NORTHEAST INTO LOWER MICHIGAN BY 18Z. PV ANOMALY
CURRENTLY OVER WEST CENTRAL TEXAS WILL BE ENTERING SOUTHEAST IOWA AS
WELL BY 12Z WITH STRONG QG FORCING CONTINUING THROUGH MID TO LATE
MORNING OVER THE SOUTHEAST. A PORTION OF THE WARM CONVEYOR WILL
CONTINUE TO SUPPLY MOISTURE INTO THE SOUTHEAST EARLY IN THE PERIOD
BEFORE DRIER AIR ADVECTS IN BY MID TO LATE MORNING. BEST SNOW
ACCUMULATIONS WILL OCCUR THROUGH 15Z THEN DIMINISHING AFTER THAT
TIME. THE MOST DIFFICULT PORTION OF THE SNOW FORECAST REMAINS THE
NORTHWEST EDGE. ANY SHIFT SOUTHEAST OF THE STORM TRACK WOULD REDUCE
SNOWFALL AMOUNT IN THESE REGIONS.
THE STRONG WIND POTENTIAL WITH THIS SYSTEM WEDNESDAY MORNING REMAINS
HIGH. IN ADDITION TO A TIGHT PRESSURE GRADIENT OF 30 TO 40
UBARS/KM...THE STRONG COLD ADVECTION WILL KEEP WINDS MIXED UP TO 900
MB WITH 35 TO 40 KTS AVAILABLE IN THAT MIXED LAYER. THE COLD
ADVECTION WILL LEAD TO GOOD MOMENTUM TRANSFER OF THE WINDS WITH
STRONGEST WINDS OCCURRING 12-18Z. AREAS WITH 2-3 INCHES OF SNOW OR
MORE WILL HAVE SIGNIFICANT BLOWING SNOW WEDNESDAY MORNING THAT COULD
APPROACH BLIZZARD CRITERIA. IN ADDITION...WITH WARMER NEAR SFC
TEMPERATURES...THE SNOW FALL COULD HAVE SIMILAR PROPERTIES TO THAT
OF THE DECEMBER BLIZZARD INITIALLY IN THAT IT WILL MELT THEN FREEZE
UNDER THE FALLING SNOW RESULTING IN AN ICY SUB LAYER. THIS WOULD
MAKE TRAVEL EXTREMELY HAZARDOUS THROUGH THIS EVENT.
THE ACCUMULATING SNOW WILL END BY NOON WITH STEADY OR FALLING
TEMPERATURES THE REMAINDER OF THE DAY. TEMPERATURES WILL BE COLD
WEDNESDAY NIGHT WITH LOWS BELOW ZERO NORTH THOUGH LINGERING CLOUDS
COULD HOLD TEMPERATURES UP OVERALL. ANOTHER UPPER WAVE WILL PUSH
THROUGH WEDNESDAY NIGHT AND THURSDAY MORNING WITH AN ARCTIC BOUNDARY
MOVING THROUGH THURSDAY AS WELL. WIND CHILL VALUES BY WEDNESDAY
NIGHT AND THURSDAY WILL APPROACH 25 BELOW OVER NORTHERN IOWA DURING
THIS PERIOD. CURRENTLY HAVE FLURRIES IN THE FORECAST FOR THURSDAY
BUT THIS WILL NEED TO BE REEVALUATED FOR POTENTIAL OF VERY LIGHT
SNOWFALL WITH A BRIEF PERIOD OF SATURATION AND LIFT THROUGH THE
DENDRITIC LAYER. ARCTIC HIGH PRESSURE WILL DROP SOUTHEAST INTO THE
STATE THURSDAY NIGHT. OVERNIGHT LOW TEMPERATURE WELL BELOW ZERO ARE
EXPECTED. POSSIBLE TO BE WELL BELOW GUIDANCE WHERE THE NEW SNOW PACK
IS.
ANOTHER UPPER LEVEL SYSTEM WILL FOLLOW THE HIGH PRESSURE DEPARTURE
BY FRIDAY AFTERNOON. ANOTHER PERIOD OF VERY LIGHT SNOW MAY OCCUR
WITH THE SYSTEM PASSAGE. GRADUAL WARMING INTO THE WEEKEND WITH
TEMPERATURES PUSHING INTO THE 20S AND 30S. THE NEXT UPPER WAVE
DROPPING THROUGH NORTHWEST FLOW WILL ARRIVE MONDAY AND WILL DROP
ANOTHER PUSH OF COLD AIR INTO THE STATE. THE COLD AIR WILL BE SHORT
LIVED WITH RIDGING BUILDING INTO FROM THE WEST BY TUESDAY.
&&
.AVIATION...30/06Z
CONFIDENCE IN NEAR BLIZZARD CONDITIONS IS WANING SOMEWHAT. DEEP
VERY STRONG FORCING UPSTREAM IS NOT RESULTING IN SNOW VISIBILITY AS
LOW AS EXPECTED. THUS STILL HAVE IFR/LIFR CONDITIONS IN THE
FORECAST...BUT MORE INFLUENCED BY CIGS RATHER THAN LIFR VSBYS.
STILL EXPECT WIND GUSTS 25-30KTS HOWEVER. ALTHOUGH LOWER VSBYS IN
SNOW SHOULD END BY MIDDAY...AT LEAST MVFR CIGS AND SOME FLURRIES
SHOULD LINGER THROUGH THE AFTERNOON WITH WINDS DIMINISHING BY THAT
TIME AS WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 9 PM THIS EVENING TO NOON CST WED
ADAIR-ADAMS-BLACK HAWK-BOONE-BREMER-BUTLER-CLARKE-DALLAS-DECATUR-
GRUNDY-HARDIN-JASPER-MADISON-MARSHALL-POLK-RINGGOLD-STORY-TAMA-
TAYLOR-UNION-WARREN-APPANOOSE-DAVIS-LUCAS-MAHASKA-MARION-MONROE-
POWESHIEK-WAPELLO-WAYNE
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST WED
AUDUBON-CARROLL-CASS-CERRO GORDO-FRANKLIN-GREENE-GUTHRIE-HAMILTON-
WEBSTER-WRIGHT
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
418 AM CST WED JAN 30 2013
.DISCUSSION...
MAIN CONCERNS FOR THE FORECAST IS SNOWFALL THIS MORNING AND
ARCTIC AIR RETURNING TO THE CWA ON THURSDAY AND FRIDAY.
TODAY THROUGH FRIDAY MORNING...SNOW HAS BEEN FALLING FOR MUCH OF THE
NIGHT WITH A HEAVY BAND THAT HAS BEEN SLOWLY TRAVERSING THE CWA
THROUGHOUT THE OVERNIGHT HOURS. HEAVIEST BAND DEVELOPED IN THE
DEFORMATION ZONE...NEAR THE AREA OF BEST MID LEVEL FRONTOGENESIS
COUPLED WITH AN AREA OF STRONG OMEGA AND NEGATIVE EPV.
HOWEVER...THE BAND WAS SLOWLY ERODING AS MODELS DEPICT THE
DISSIPATION OF THE FRONTGENESIS AS THE BETTER FORCING MOVES
NORTHEAST. THEREFORE...SHOULD SEE THE HEAVIEST BAND CONTINUE TO
ERODE THROUGHOUT THE MORNING AS IT PUSHES SOUTHEAST. LIGHT SNOW
WILL EVENTUALLY TAPER OFF DURING THE MORNING HOURS WITH THE FAR
EASTERN COUNTIES SEEING AN END AROUND THE NOON HOUR AS THE BETTER
FORCING AGAIN LIFTS TO THE NORTHEAST. BECAUSE OF THE SLOWER
MOVEMENT OF THE PRECIPITATION...OPTED TO EXTEND THE WINTER WEATHER
ADVISORIES TILL 9 AM FOR THE WESTERN COUNTIES AND NOON FOR THE
EASTERN COUNTIES. TOTAL SNOW ACCUMULATIONS WILL BE GREATEST NORTH
OF INTERSTATE 70 WITH 2 TO 4 INCHES AND LOCALLY HIGHER AMOUNTS TO
NEAR 6 INCHES. SOUTH OF INTERSTATE 70...TOTAL ACCUMULATIONS OF 1
TO 3 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WINDS PICKING UP
TO 35 MPH WILL ALSO CAUSE CAUSE BLOWING AND DRIFTING AS WELL AS
REDUCED VISIBILITIES ESPECIALLY THIS MORNING. AFTERNOON HIGHS
TODAY WILL REACH INTO THE 20`S TO LOW 30`S.
LONGWAVE TROUGH MOVES OUT OF THE CWA THIS AFTERNOON AS 85KT 500MB
JET CORE ASSOCIATED WITH THE NEXT SHRTWV PUSHES IT TO THE EAST AND
GIVES THE LONGWAVE TROUGH A BIT OF A NEGATIVE TILT OVER THE OHIO VALLEY.
SURFACE LOW DEVELOPS OVER THE WESTERN HIGH PLAINS TONIGHT IN
RESPONSE TO THE SHRTWV...WHICH WILL CAUSE WINDS TO BRIEFLY SWITCH
TO THE WEST/SOUTHWEST THIS EVENING AND TONIGHT. HIGH TEMPERATURES
FOR THE DAY THURSDAY WILL BE REALIZED DURING THE MORNING HOURS
WITH HIGHS IN THE 20`S AS AN ARCTIC COLD FRONT IS PUSHED RAPIDLY
SOUTHEAST ACROSS THE PLAINS AND INTO THE CWA BY THURSDAY MORNING.
SIGNIFICANT CAA WILL LAG BEHIND THE FRONT UNTIL THE AFTERNOON WHERE
TEMPERATURES SHOULD BEGIN DROPPING AFTER THE NOON HOUR.
TEMPERATURES BY SUNSET WILL ONLY BE IN THE TEENS AND LOW 20`S BY
SUNSET. OVERNIGHT LOWS WILL BE BITTERLY COLD WITH LOWS IN THE
SINGLE DIGITS FOR MUCH OF THE CWA. WITH GUSTY WINDS TO AROUND 25
MPH THURSDAY AFTERNOON...COULD SEE WIND CHILLS BELOW ZERO OVER THE
FAR NORTHERN COUNTIES AND SINGLE DIGITS FOR THE REST OF THE AREA.
BYRNE
LONG TERM (FRIDAY AND TUESDAY)...
FRIDAY...THE DEEPER LONGER WAVE-LENGTH UPPER LEVEL TROUGH ACROSS THE
GREAT LAKES AND OH RIVER VALLEY WILL SHIFT EAST INTO NEW ENGLAND AND
THE MID ATLANTIC STATES. THE SFC RIDGE OF HIGH PRESSURE WILL ALSO
SHIFT EAST ACROSS THE MID AND LOWER MS RIVER VALLEY. HIGHS ON FRIDAY
WILL WARM SLIGHTLY...THOUGH DEEPER SNOW COVER ACROSS THE NORTHERN
HALF OF THE CWA MAY KEEP HIGHS IN THE LOWER TO MID 30S...WITH MID
TO UPPER 30S ACROSS THE SOUTHERN COUNTIES.
FRIDAY NIGHT THROUGH WEDNESDAY...THE UPPER LEVEL FLOW WILL BE
WEST-NORTHWEST ACROSS THE PLAINS. EXPECT DRY CONDITIONS.
I KEPT HIGHS COOLER ON SATURDAY ACROSS THE NORTHERN COUNTIES OF THE
CWA DUE TO THE SNOW COVER. SATURDAY HIGHS WILL RANGE FROM THE UPPER
30S ALONG THE NE BORDER TO THE MID AND UPPER 40S SOUTH OF I-70.
HIGHS WILL SLOWLY WARM INTO THE LOWER TO MID 50S SUNDAY THROUGH
TUESDAY.
GARGAN
&&
.AVIATION...
DEFORMATION BAND OF SNOW HAS FORMED TO THE WEST OF THE
TERMINALS...AND THE RAP AND NAM CONTINUE TO SHOW THIS BAND MOVING
ACROSS NORTHEAST KANSAS OVERNIGHT. TIMING IS SEVERAL HOURS SLOWER
FROM THE PREV FORECAST WITH SNOW LIKELY PERSISTING AT TOP AND FOE
UNTIL 14Z. MODELS ALSO SUGGEST A LACK OF ICE IN THE TOP OF THE CLOUD
INITIALLY. WITH SEVERAL REPORTS OF PL UPSTREAM...HAVE INTRODUCED A
MIX OF -SNPL UNTIL THE BETTER DEFORMATION BAND MOVES IN AND
SATURATES THE DENDRITIC GROWTH ZONE FOR A PERIOD OF MODERATE SNOW.
CONFIDENCE IS HIGH THAT THERE WILL BE IFR AND LIFR CONDITIONS DURING
THE NEXT 8 TO 12 HOURS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR
KSZ008>010-020>023-034>038.
WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ011-012-
024-026-039-040.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1134 PM CST TUE JAN 29 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
DEFORMATION BAND OF SNOW HAS FORMED TO THE WEST OF THE
TERMINALS...AND THE RAP AND NAM CONTINUE TO SHOW THIS BAND MOVING
ACROSS NORTHEAST KANSAS OVERNIGHT. TIMING IS SEVERAL HOURS SLOWER
FROM THE PREV FORECAST WITH SNOW LIKELY PERSISTING AT TOP AND FOE
UNTIL 14Z. MODELS ALSO SUGGEST A LACK OF ICE IN THE TOP OF THE CLOUD
INITIALLY. WITH SEVERAL REPORTS OF PL UPSTREAM...HAVE INTRODUCED A
MIX OF -SNPL UNTIL THE BETTER DEFORMATION BAND MOVES IN AND
SATURATES THE DENDRITIC GROWTH ZONE FOR A PERIOD OF MODERATE SNOW.
CONFIDENCE IS HIGH THAT THERE WILL BE IFR AND LIFR CONDITIONS DURING
THE NEXT 8 TO 12 HOURS.
WOLTERS
&&
.PREV DISCUSSION... /957 PM CST TUE JAN 29 2013/
A BAND OF SNOW HAS DEVELOPED ACROSS SOUTHWESTERN AND CENTRAL KANSAS
WITHIN THE DEFORMATION ZONE OF THE UPPER TROUGH. THE LATEST RAP AND
NAM PROGS SUGGEST THIS BAND OF SNOW WILL CONTINUE TO MOVE EAST AND
NORTHEAST ACROSS THE NORTHERN TWO THIRDS OF THE FORECAST AREA...WITH
THE HEAVIEST BAND SETTING UP NORTH OF AN ABILENE TO HOLTON LINE.
MODELS HAVE ALSO TRENDED SOUTH WITH THE SNOW ACCUMULATIONS AND SHOW
A COUPLE INCHES POSSIBLE ALONG INTERSTATE 70. WITH MODELS STILL
SHOWING DECENT FRONTOGENETICAL FORCING AND THE DEFORMATION BAND
HAVING ALREADY FORMED...HAVE EXPANDED THE ADVISORY A LITTLE FURTHER
SOUTH TO INCLUDE DICKINSON...GEARY...MORRIS AND WABAUNSEE COUNTIES.
WOLTERS
/556 PM CST TUE JAN 29 2013/
21Z RAP AND 18Z NAM HAVE STARTED TO SHOW SOME INDICATION OF A DECENT
FRONTOGENETICAL BAND DEVELOPING MAINLY DURING THE 06Z TO 12Z TIME
FRAME. WITH RECENT RADAR TRENDS SHOWING A BAND STARTING TO FORM
ACROSS WESTERN KS...AM BEGINNING TO THINK THAT MODELS ARE DOING A
REASONABLE JOB DEPICTING THE SYSTEM AS IT LIFTS OUT OVERNIGHT.
CONFIDENCE IS INCREASING THAT THERE WILL BE SNOW. SNOW AMOUNTS SEEM
TO BE IN THE BALLPARK INITIALLY. WITH SOME UNCERTAINTY FROM THE PREV
FORECAST ABOUT MESOSCALE FORCING...THINK THAT FORECAST SNOW AMOUNTS
ARE PROBABLY NOT ON THE LOW SIDE. THERE ARE STILL SOME QUESTIONS
WITH SOME INDICATIONS OF MID LEVEL DRY AIR COMING IN AT THE
DENDRITIC GROWTH ZONE AND A GENERAL LACK OF INSTABILITY OF
CONDITIONAL INSTABILITY THAT COULD ACT TO KEEP SNOW AMOUNT ON WITHIN
THE FORECASTED VALUES. IF ANYTHING WILL NEED TO WATCH THINGS
PROGRESS AND POTENTIALLY EXPAND THE ADVISORY IF INDEED A BAND OF
MODERATE SNOW MOVES ACROSS THE AREA. MODELS CONTINUE TO SHOW A
STRENGTHENING PRESSURE GRADIENT WITH NORTH AND NORTHWEST WINDS
GUSTING UP TO 35 MPH.
WOLTERS
/328 PM CST TUE JAN 29 2013/
THE ABRUPT RETURN TO WINTER CONTINUES TODAY ACROSS THE FORECAST
AREA...AFTER A ROUND OF MORNING SHOWERS AND THUNDERSTORMS FOR
EASTERN PORTIONS OF THE STATE. THE DEEP LONGWAVE TROF CONTINUES TO
MOVE EASTWARD ACROSS THE ROCKY MOUNTAINS AND INTO THE HIGH PLAINS.
ENERGY ROTATING THROUGH THE TX PANHANDLES AIDING IN ENHANCING A
NEGATIVE TILT TO THE SOUTHERN STREAM AS IT LIFTS INTO OUR AREA
THIS EVENING AND OVERNIGHT.
HAVE EXPANDED THE WINTER WEATHER ADVISORY BOTH WEST AND SOUTH A
FEW COUNTIES. STILL APPEARS AS IF FAR NE COUNTIES WILL GET THE
HIGHER SNOW AMOUNTS WHERE BAND OF FRONTOGENESIS TRACKS WEST TO
EAST GENERALLY NORTH OF THE INTERSTATE...AS DOES THE MID LEVEL
DEFORMATION ZONE. HARD TO SEE A TIME WHEN ALL INGREDIENTS COME
TOGETHER FOR A BANDED HEAVY SNOW EVENT...ALTHOUGH AROUND 06Z
NORTH OF THE MHK AREA DO SEE SOME FRONTOGENETIC FORCING ALIGNED
WITH SOME NEGATIVE EPV...THEREFORE INCREASED SNOW TOTALS FOR THIS
AREA. 2-3 INCH LINE RUNS GENERALLY ALONG THE INTERSTATE WITH
DIMINISHING AMOUNTS SOUTH AND HIGHER NUMBERS NORTH AND EAST.
STARTED ADVISORY WEST AT 6PM FOLLOWED BY AN 11PM START FOR
COUNTIES FARTHER EAST. OF CONCERN ARE THE WINDS THAT ACCOMPANY THIS
SYSTEM AS THE SNOW FALLS OVERNIGHT AND INTO THE EARLY COMMUTE
TOMORROW MORNING. SNOW WILL REDUCE VISIBILITIES AND MAY MAKE ROADS
DIFFICULT TO KEEP CLEAR...SO THAT EVEN A FEW INCHES OF SNOW MAY
BRING TRAVEL PROBLEMS. SNOW SHOULD END BY 9AM AND WILL LIKELY END
A FEW HOURS SOONER OUT WEST AND CAN ADJUST ADVISORY ENDING AS
NEEDED.
THURSDAY THROUGH NEXT TUESDAY...DRY WEATHER WILL LIKELY CONTINUE
THROUGH THE REMAINDER OF THE FORECAST PERIOD AS COLD AND DRY AIR
PLUNGES SOUTHWARD INTO THE CENTRAL PLAINS. NORTHWEST FLOW ALOFT ON
THE EASTERN EDGE OF A STRONGLY AMPLIFIED RIDGE OVER THE WESTERN
CONUS WILL PREVENT THE FORMATION OF ANY STRONG SURFACE TROUGH AND
SUBSEQUENT WARM AIR ADVECTION THROUGH THE REST OF THE WORK WEEK. THE
FIRST PUSH OF COLD AIR WILL ALSO LIKELY BE REINFORCED BY A SECOND
PUSH OF COLD AIR ON THURSDAY NIGHT...WHICH MODELS CURRENTLY PROG TO
BE CHARACTERIZED BY 850 MB TEMPERATURES AROUND -15 DEGREES C. THE
COLDEST MORNING AT THIS TIME LOOKS TO BE FRIDAY MORNING...WHEN THE
SURFACE HIGH ASSOCIATED WITH THE ARCTIC AIRMASS BECOMES CENTERED
OVER NORTHEAST KANSAS. CURRENTLY THE FORECAST FOR FRIDAY MORNING
REFLECTS SLIGHTLY LOWER TEMPS THAN THE PREVIOUS FORECAST SUGGESTED
DUE TO THE FACT THAT SNOW FROM TUESDAY NIGHT/WED MORNING WILL LIKELY
LINGER PREVENTING THE POLAR AIR FROM MODIFYING MUCH. GIVEN THAT SNOW
WILL LIKELY STILL BE ON THE GROUND AND THAT SKIES WILL CLEAR AND
WINDS WILL BE CALM...IN RESPONSE TO THE SURFACE HIGH...EXPECT FRIDAY
MORNING TO BE VERY CHILLY...WITH LOWS IN THE SINGLE DIGITS TO LOWER
TEENS.
BY SATURDAY THE SURFACE HIGH WILL SLIDE EASTWARD AND SOUTHERLY
RETURN FLOW WILL COMMENCE ON THE BACKSIDE OF THE HIGH. CONCURRENTLY
THE AFOREMENTIONED WESTERN CONUS RIDGE MAY SHIFT EVER SO SLIGHTLY TO
THE EAST...ALLOWING THE COLD AIR ASSOCIATED WITH THE BROAD HUDSON
BAY LOW TO ALSO SHIFT EAST. THE BOTTOM LINE FOR THE WEEKEND AND INTO
NEXT WEEK IS A GRADUAL WARMING TREND AS SURFACE WINDS WILL BE
WESTERLY TO SOUTHWESTERLY...WHICH WILL INTRODUCE A SLIGHT DOWNSLOPE
COMPONENT...AIDING IN SURFACE TEMP WARMING. AT THIS POINT MAX TEMPS
LOOK TO RUN ABOUT 10 DEGREES ABOVE NORMAL FROM SUNDAY THROUGH
NEXT TUESDAY...BUT THIS COULD CHANGE A FEW DEGREES EITHER WAY
DEPENDING ON HOW FAST THE SNOW MELTS.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY TIL 7AM WED FOR KSZ008-009-020>022-034>037.
WINTER WEATHER ADVISORY TIL 9AM WED KSZ010>012-023-024-026-038>040.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
653 PM EST THU JAN 31 2013
...Updated Aviation Discussion...
.Short Term (Tonight through Friday Night)...
Issued at 230 PM EST Thu Jan 31 2013
...Winter Weather Advisory for Numerous Snow Squalls This Evening...
The scattered light to moderate snow showers are diminishing across
the area early this afternoon and they will continue to push off to
the east. A lull in the action will then occur through the remainder
of the afternoon. Temperatures will actually rise just above
freezing for a few hours, and the evening rush hour is expected to
be smooth. After the mid to late afternoon lull, a nearly solid line
of convective snow showers will develop from southwestern Indiana to
western Kentucky early this evening. This line of snow showers will
then intensify over the area as it moves quickly east. The best
timing looks to be between 6 PM EST and Midnight, although snow will
only last for 3 or 4 hours tops at any one location.
Forecast soundings are quite impressive with low level lapse rates
and deep moisture through the dendritic growth zone. Cold air
advection will occur at all levels as the system dives into the
area, so snow ratios will approach 15-20:1. This should help
maximize the low amounts of QPF. Overall, variable accumulations
between a half an inch and 2 inches will occur due to the convective
nature of the snow showers. The most likely locations for the
highest amounts will be along the I-75 corridor and across southeast
Kentucky where 1 to 2 inches may occur, elsewhere a half an inch to
1 inch is expected. Mainly issued this advisory due to the intensity
of the expected snow squalls, and their expected impact to travel.
Conditions will likely deteriorate over very short distances,
including all major interstate corridors through the area. Wind will
also likely gust up around 30 mph at times with these showers, so
blowing dry snow will also make conditions treacherous. Finally, the
rapidly dropping temperatures, may help some wet areas to quickly
re-freeze adding to the slick spots on roadways. Some sort of
product (SPS, travelers advisory) may need to be extended into the
morning commute, depending on conditions, even though precipitation
will be long gone.
Temperatures will crash behind the surface front of this system
tonight, with lows dropping into the lower teens by dawn. With
surface winds expected to still be in the 10 to 15 mph range during
this time, wind chills will drop into the 5 above zero to 5 below
zero range Friday morning. The below zero values will most likely be
along and north of the Ohio River. Surface high pressure then builds
across the region for Friday with struggling high temperatures only
in the low and mid 20s. Temperatures may end up being lower in many
spots if a fresh light snow remains on the surface.
Surface highs slides east on Friday night with another clipper
system diving into the nearly zonal flow toward dawn on Saturday.
This portion of the forecast will be handled below. Lows on Friday
night will be in the mid teens (east) to around 20 elsewhere. These
will occur fairl early in the overnight with temperatures likely
rising a bit toward dawn.
.Long Term (Saturday through Thursday)...
Issued at 230 PM EST Thu Jan 31 2013
Another cold front will bring wintry weather Saturday. Low pressure
pushing this front will start off 12Z Saturday near the borders of
IL/IA/MO. The front itself is progged to be over our western
forecast area by 00Z Sunday and moving through Saturday night. Then
another front/wind shift moves across the region Sunday morning.
Then clipper-palooza continues with another system forecast to move
through the region Monday night followed by one more Tuesday night.
Then another system looks to be organizing for Tuesday to our west.
Given the quick moving nature of each disturbance, confidence drops
quickly in the forecast elements the farther out in time you go.
Have enough confidence, based on multiple model output for QPF
Saturday to indicate another likely advisory-level winter event. The
main question is if our south will see more of a mix of rain and
snow. Previous forecasts have indicated a dropping of temperatures
as the precip initiates, so that should keep the most precip type to
snow. Tonight`s snows will bring cooler temperatures than the models
are forecasting for Friday/Friday night. Thus think even our south
forecast area will see some snow, though cannot rule out a brief
transition period as high temps for the day occur.
As for amounts with the Saturday system, the pattern looks somewhat
similar to a type that has brought 2" snowfall totals to the region.
Snow ratios from Bufkit indicate about a 15-1 value, and soundings
indicate plenty of deep cold air in place for good snow growth.
Based on QPF forecasts and this ratio, have totals across the region
of half an inch to around 2 inches, with the latter over the
Bluegrass.
Available moisture drops off more for the Sunday system, so think
the best chance for any additional precipitation would be in the
fetch coming down from Lake Michigan, across the Bluegrass.
Given the lower confidence mentioned above for later in the period,
will continue to use a blended forecast for the weather elements.
&&
.Aviation (00Z TAF Issuance)...
Issued at 650 PM EST Thu Jan 31 2013
A weak clipper system is approaching from the west, with snow
falling along and north of the Ohio River from CVG southwest to CGI.
This will progress east-southeast through the evening hours,
providing snow to all TAF sites. Upstream observations indicate at
least IFR vis and MVFR cig, but any location directly under the
heaviest band will likely experience IFR to LIFR conditions. This
should be a quick hit, with fuel alternate conditions only lasting 2
to perhaps 3 hours. There will also be a wind shift from southwest
to west-northwest during the event, as a cold front pushes through.
Winds will gust up to around 30 knots for a few hours following the
frontal passage, with snow coming to an end. After looking at the
latest RAP data and coordinating with the meteorologists at UPS,
have fuel alternate conditions at SDF from 01-03Z, with the wind
shift occurring at 02Z. These conditions will impact BWG and LEX an
hour or two later. Skies will then clear or begin to clear during
the early morning hours in the wake of the system, with VFR
conditions prevailing at all sites through the remainder of the TAF
period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 2 AM EST /1 AM CST/ FRIDAY FOR
INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 2 AM EST /1 AM CST/ FRIDAY FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
$$
Short Term.......BJS
Long Term........RJS
Aviation.........MJP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1158 PM EST TUE JAN 29 2013
...Updated Aviation Discussion...
.Mesoscale Forecast Update...
1115 PM EST Tue Jan 30 2013
Updated the zones and other public products to include tornado watch
number 12 which is in effect until 5 AM EST Wednesday.
Forecast continues to be on target for the overnight period. Severe
QLCS is in progress to the west of our area and is approaching the
Wabash and Ohio Rivers in far western Kentucky. Upstream reports
from WFO Paducah reveal quite a bit of wind damage with this linear
system. Mesoscale analysis continues to show more than 70kts of
effective shear which should increase a bit more over the next few
hours. VAD wind profiles from PAH still show nearly 100kts of wind
at 4000 ft AGL and calculating SRH from the VAD profiles show 0-1KM
SRH of 550-650 M2/S2 and 0-3KM SRH of over 1000 M2/S2. Thus, with
the shear and the strong theta-e advection mixing out the low-level
inversion, this line should become more surface rooted and increase
in intensity as it heads east. Damaging winds are very likely with
this line overnight and embedded tornadoes within QLCS mesovortices
and bowing line segments are likely.
Based on current progression, this activity should be on our border
with WFO PAH around 1230-130 AM EST and in the I-65 corridor
including Louisville around 2-3 AM and then toward the I-75 between
3-5 AM EST. This is a little faster than previously indicated due
to the fact that the line is speeding up a bit due to cold pool
generation behind the line.
Previously issued at 830 PM EST Tue Jan 30 2013
Surface low is beginning to strengthen across Missouri as
upper-level energy pushes eastward. As of 800 PM, the cold front
extends southwest from Lake Michigan, through Illinois, Missouri,
and into Oklahoma. Convection has been ongoing this afternoon and
evening ahead of the front. While there were severe storms that
impacted the St. Louis metropolitan area earlier, but this has
diminished in strength as it currently pushes into central Illinois.
The airmass across central Illinois and into our area is still
fairly stable. Aircraft soundings confirm what the models have been
predicting, which is a low-level inversion. The main concern is the
convection ongoing across south-central Missouri and northern
Arkansas, which is showing better signs of organizing. As indicated
with the latest Mesoscale Discussion from SPC, this will likely be
the line that will continue to propagate east impacting our area
overnight. As this line approaches, the cap will weaken as theta-e
advection increases, which is evident with a few low-topped showers
developing around the region.
As advertised for several days now, the shear will be quite
impressive as the line gets into our area. Effective bulk shear
currently ahead of the line (across western KY) is 55+ knots, with
effective SRH up to about 500 m2/s2. All guidance continues to peg
high shear in a weakly unstable environment for us as this
convective line gets into our area. With the surface low
strengthening as it tracks northeast and 55+ knot winds at 1900 ft
AGL, would expect the severe potential to continue into southern
Indiana/central Kentucky. Damaging winds with the line will be the
main threat as it becomes better organized over the next few hours.
Embedded circulations within bowing segments will continue to be a
threat as well, so isolated tornadoes remain in play. Overall timing
has not changed, with models still showing slight timing
differences. Latest RAP is a tad slower than our current forecast,
but if the line surges with better cold pool forcing, then we are
pretty much on schedule.
Aside from the strong winds associated with the convection, gradient
winds continue to strengthen. Some gusts are currently around 30
knots, with stronger winds likely as this system approaches.
&&
.Short Term (Tonight through Wednesday Night)...
Issued at 320 PM EST Tue Jan 29 2013
...Strong to Severe Storms Expected Early Wednesday Morning With
Wind Damage and Isolated Tornadoes Being The Main Threats...
Models continue to remain in good agreement on severe weather threat
for tonight, and upstream development is matching up well with
high-res forecasts. MSAS analysis at 19Z indicated a broad 998 mb
low, stretching from eastern OK to southwest MO. By 06Z tonight,
models forecast this low to drop to around 990 mb near KLOT and
continuing to deepen towards daybreak.
A powerful low-level jet will develop overnight in response to this
deepening. Models continue to indicate this jet will be on the order
of 70-80 knots at 850 mb. Gradient winds ahead of the main line
still are expected to be fairly gusty. Speeds are marginal for a
wind advisory, but guidance usually does not handle nighttime winds
as well in these situations, so will continue the wind advisory.
Temperatures remaining in the 60s through the night will mean that a
squall line that forms out of the storms to our west this afternoon
will find a favorable environment to maintain itself through the
forecast area. Low level wind shear is mostly unidirectional, but
storm relative helicities are very high. We may see some discrete
cells develop ahead of the line which would be able to take more
advantage of more southerly winds ahead of the line to produce
tornadoes. The line itself likely will produce damaging winds as
the strong winds aloft get mixed down. Also cannot rule out some
embedded tornadoes within the line in the stronger meso`s that form.
The threat for flash flooding seems less with each run, as the width
of the band thins out some. For now have QPF for the
tonight/Wednesday time period at around an inch, though isolated
higher amounts are possible. Area rivers should be able to handle
this water.
Guidance for winds behind the main line pick up again Wednesday
afternoon. Should we get any breaks in the clouds, we easily could
see another round of 30-40 knot winds, so current timing on the wind
advisory looks good. The cold front associated with this low
pressure system will not get into the region until late in the
afternoon Wednesday. West/northwest winds will stay up Wednesday
night as much colder air pours into the area. We may see a brief
period of snow as lingering precipitation ahead of the main upper
trough and nearer the front remains into the night. Accumulations
look minor at this point, mainly over the Bluegrass if at all.
.Long Term (Thursday through Tuesday)...
Issued at 325 PM EST Tue Jan 29 2013
A shortwave and weak surface boundary looks to move through the Ohio
Valley Thursday afternoon/evening, bringing a slight chance for
light rain/snow showers to south-central Indiana. Once the
temperatures drop below freezing that night, expect any rain showers
to change over to snow completely as central Kentucky and southern
IN gets locked under a cold, Canadian airmass. Since models appear
to be trending a bit cooler, have dropped min temps Thursday
overnight/Friday morning into the upper teens and lower 20s. These
temps don`t look to rebound above the freezing mark on Friday
afternoon so look for clearing skies as the disturbance moves off
toward the east and surface high pressure briefly drops in.
The next disturbance appears to begin affecting the northern and
western portions of the forecast area by Saturday morning with light
snow shower chances for the north and light rain showers elsewhere.
As the temps rise above freezing, any snow that does fall early on
should switch over to mostly rain as the entire thermal profile
warms up. Even though temps will fall back into the 20s overnight
Saturday, the precip should exit to the east before approaching the
freezing mark again.
For the remainder of the weekend, southerly flow will return to the
region, warming temps into the 40s and 50s Sunday-Monday. However,
the rain is anticipated to return ahead of a cold front Monday in
the form of rain. The rain should be out by the start of the day on
Tuesday with the frontal passage. This leads temps to take on a
non-diurnal curve on Tuesday as the warmest temps of the day should
occur early on. As always is the case for this time of year, any
changes to the thermal profile forecast could change precip types
but for now, there appears to be general model consensus in the
anticipated overall pattern for this time frame. Any snow that is
able to stick to surfaces should be very light in accumulations.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1158 PM EST Tue Jan 29 2013
Deep upper trough over the Plains will drive a surface low pressure
system from the Plains and into the Great Lakes during the day on
Wednesday. Strong surface cold front is located to our west with a
pre-frontal trough axis out ahead of the cold front. Quasi-linear
convective system is well developed and located along the IN/IL/KY
border area and heading east at around 50kts.
Based on the latest radar data, this line will impact the KBWG
terminal around 0630-0830Z. It should be reaching the KSDF terminal
around 0700-0800Z and the KLEX terminal around 0900-1000Z. Have
continued to advertise a period of VCTS just before the above
mentioned times to account for any development that may occur ahead
of the line. Will be keeping a very close met watch on the TAF`s
tonight and will be updating to time the lines into the terminals as
they approach. Feel that conditions will be quite poor when the
squalls go through. Variable winds of 25G35kt will be possible for
a time. LLWS will continue to be a problem until the main
convective line passes.
MVFR cigs will continue behind the line with conditions not
improving until mid-late morning. Previous thinking of a second
low-topped line of convection developing still looks like a
possibility and we`ll address those issues in later forecasts.
&&
.Hydrology...
Issued at 300 AM EST Tue Jan 29 2013
No real changes in the forecast thinking on the hydrologic front.
An intense line of strong to severe thunderstorms is forecast to
move across the region late tonight and early Wednesday morning. In
addition to the threat of damaging winds, these storms will likely
produce heavy rainfall. Once the system pulls east on Wednesday
morning, a period of stratiform rainfall will likely persist for a
few hours.
Rainfall amounts averaging a little more than an inch in 6 hours
should be widespread. Isolated amounts of up to 2 inches are
possible. This rain could result in brief small stream flooding and
later rises on larger rivers. Any flooding that will occur should be
minor due to the fast nature of these storms. The rain will taper to
scattered showers Wednesday afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ WEDNESDAY FOR
INZ076>079-
083-084-089>092.
KY...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ WEDNESDAY FOR
KYZ023>032-
061-062-070>072.
WIND ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
KYZ033>043-
045>049-053>057-063>067-073>078-081-082.
$$
Mesoscale........MJ/MJP
Short Term.......RJS
Long Term........lg
Aviation.........MJ
Hydrology........CMC
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1118 PM EST TUE JAN 29 2013
.Mesoscale Forecast Update...
1115 PM EST Tue Jan 30 2013
Updated the zones and other public products to include tornado watch
number 12 which is in effect until 5 AM EST Wednesday.
Forecast continues to be on target for the overnight period. Severe
QLCS is in progress to the west of our area and is approaching the
Wabash and Ohio Rivers in far western Kentucky. Upstream reports
from WFO Paducah reveal quite a bit of wind damage with this linear
system. Mesoscale analysis continues to show more than 70kts of
effective shear which should increase a bit more over the next few
hours. VAD wind profiles from PAH still show nearly 100kts of wind
at 4000 ft AGL and calculating SRH from the VAD profiles show 0-1KM
SRH of 550-650 M2/S2 and 0-3KM SRH of over 1000 M2/S2. Thus, with
the shear and the strong theta-e advection mixing out the low-level
inversion, this line should become more surface rooted and increase
in intensity as it heads east. Damaging winds are very likely with
this line overnight and embedded tornadoes within QLCS mesovortices
and bowing line segments are likely.
Based on current progression, this activity should be on our border
with WFO PAH around 1230-130 AM EST and in the I-65 corridor
including Louisville around 2-3 AM and then toward the I-75 between
3-5 AM EST. This is a little faster than previously indicated due
to the fact that the line is speeding up a bit due to cold pool
generation behind the line.
Previously issued at 830 PM EST Tue Jan 30 2013
Surface low is beginning to strengthen across Missouri as
upper-level energy pushes eastward. As of 800 PM, the cold front
extends southwest from Lake Michigan, through Illinois, Missouri,
and into Oklahoma. Convection has been ongoing this afternoon and
evening ahead of the front. While there were severe storms that
impacted the St. Louis metropolitan area earlier, but this has
diminished in strength as it currently pushes into central Illinois.
The airmass across central Illinois and into our area is still
fairly stable. Aircraft soundings confirm what the models have been
predicting, which is a low-level inversion. The main concern is the
convection ongoing across south-central Missouri and northern
Arkansas, which is showing better signs of organizing. As indicated
with the latest Mesoscale Discussion from SPC, this will likely be
the line that will continue to propagate east impacting our area
overnight. As this line approaches, the cap will weaken as theta-e
advection increases, which is evident with a few low-topped showers
developing around the region.
As advertised for several days now, the shear will be quite
impressive as the line gets into our area. Effective bulk shear
currently ahead of the line (across western KY) is 55+ knots, with
effective SRH up to about 500 m2/s2. All guidance continues to peg
high shear in a weakly unstable environment for us as this
convective line gets into our area. With the surface low
strengthening as it tracks northeast and 55+ knot winds at 1900 ft
AGL, would expect the severe potential to continue into southern
Indiana/central Kentucky. Damaging winds with the line will be the
main threat as it becomes better organized over the next few hours.
Embedded circulations within bowing segments will continue to be a
threat as well, so isolated tornadoes remain in play. Overall timing
has not changed, with models still showing slight timing
differences. Latest RAP is a tad slower than our current forecast,
but if the line surges with better cold pool forcing, then we are
pretty much on schedule.
Aside from the strong winds associated with the convection, gradient
winds continue to strengthen. Some gusts are currently around 30
knots, with stronger winds likely as this system approaches.
&&
.Short Term (Tonight through Wednesday Night)...
Issued at 320 PM EST Tue Jan 29 2013
...Strong to Severe Storms Expected Early Wednesday Morning With
Wind Damage and Isolated Tornadoes Being The Main Threats...
Models continue to remain in good agreement on severe weather threat
for tonight, and upstream development is matching up well with
high-res forecasts. MSAS analysis at 19Z indicated a broad 998 mb
low, stretching from eastern OK to southwest MO. By 06Z tonight,
models forecast this low to drop to around 990 mb near KLOT and
continuing to deepen towards daybreak.
A powerful low-level jet will develop overnight in response to this
deepening. Models continue to indicate this jet will be on the order
of 70-80 knots at 850 mb. Gradient winds ahead of the main line
still are expected to be fairly gusty. Speeds are marginal for a
wind advisory, but guidance usually does not handle nighttime winds
as well in these situations, so will continue the wind advisory.
Temperatures remaining in the 60s through the night will mean that a
squall line that forms out of the storms to our west this afternoon
will find a favorable environment to maintain itself through the
forecast area. Low level wind shear is mostly unidirectional, but
storm relative helicities are very high. We may see some discrete
cells develop ahead of the line which would be able to take more
advantage of more southerly winds ahead of the line to produce
tornadoes. The line itself likely will produce damaging winds as
the strong winds aloft get mixed down. Also cannot rule out some
embedded tornadoes within the line in the stronger meso`s that form.
The threat for flash flooding seems less with each run, as the width
of the band thins out some. For now have QPF for the
tonight/Wednesday time period at around an inch, though isolated
higher amounts are possible. Area rivers should be able to handle
this water.
Guidance for winds behind the main line pick up again Wednesday
afternoon. Should we get any breaks in the clouds, we easily could
see another round of 30-40 knot winds, so current timing on the wind
advisory looks good. The cold front associated with this low
pressure system will not get into the region until late in the
afternoon Wednesday. West/northwest winds will stay up Wednesday
night as much colder air pours into the area. We may see a brief
period of snow as lingering precipitation ahead of the main upper
trough and nearer the front remains into the night. Accumulations
look minor at this point, mainly over the Bluegrass if at all.
.Long Term (Thursday through Tuesday)...
Issued at 325 PM EST Tue Jan 29 2013
A shortwave and weak surface boundary looks to move through the Ohio
Valley Thursday afternoon/evening, bringing a slight chance for
light rain/snow showers to south-central Indiana. Once the
temperatures drop below freezing that night, expect any rain showers
to change over to snow completely as central Kentucky and southern
IN gets locked under a cold, Canadian airmass. Since models appear
to be trending a bit cooler, have dropped min temps Thursday
overnight/Friday morning into the upper teens and lower 20s. These
temps don`t look to rebound above the freezing mark on Friday
afternoon so look for clearing skies as the disturbance moves off
toward the east and surface high pressure briefly drops in.
The next disturbance appears to begin affecting the northern and
western portions of the forecast area by Saturday morning with light
snow shower chances for the north and light rain showers elsewhere.
As the temps rise above freezing, any snow that does fall early on
should switch over to mostly rain as the entire thermal profile
warms up. Even though temps will fall back into the 20s overnight
Saturday, the precip should exit to the east before approaching the
freezing mark again.
For the remainder of the weekend, southerly flow will return to the
region, warming temps into the 40s and 50s Sunday-Monday. However,
the rain is anticipated to return ahead of a cold front Monday in
the form of rain. The rain should be out by the start of the day on
Tuesday with the frontal passage. This leads temps to take on a
non-diurnal curve on Tuesday as the warmest temps of the day should
occur early on. As always is the case for this time of year, any
changes to the thermal profile forecast could change precip types
but for now, there appears to be general model consensus in the
anticipated overall pattern for this time frame. Any snow that is
able to stick to surfaces should be very light in accumulations.
&&
.Aviation (00Z TAF Issuance)...
Issued at 642 PM EST Tue Jan 29 2013
Deep upper-level trough over the Eastern Rockies will force a
surface low pressure system now over the southern Plains to
intensify and head quickly toward the Midwest this evening and
overnight. The pressure gradient is beginning to tighten ahead of
this low, with southerly winds starting to increase/gust. Latest
wind profile guidance from CWSU ZSE indicates low-level wind shear
is likely overnight, with 50-60 knots around 1900 feet AGL. So, will
continue LLWS for all TAF sites. Convection currently across
Illinois, Missouri, and Arkansas will form a more organized line of
thunderstorms as the surface low strengthens tonight. This line will
eventually move east through all TAF sites. Have put in the best
thoughts for timing the actual line. Added VCTS a couple hours prior
to account for any development ahead of the line. Some guidance
indicates there could be two lines of convection. Will hit the TAFs
harder when the line does approach. Expect MVFR cigs through most of
the night, with conditions not improving until mid-late morning
Wednesday. By late Wednesday afternoon, there could be low-topped
showers/thunderstorms on the back side of this system, so will
continue with VCSH through the end of the TAF period for now.
&&
.Hydrology...
Issued at 300 AM EST Tue Jan 29 2013
No real changes in the forecast thinking on the hydrologic front.
An intense line of strong to severe thunderstorms is forecast to
move across the region late tonight and early Wednesday morning. In
addition to the threat of damaging winds, these storms will likely
produce heavy rainfall. Once the system pulls east on Wednesday
morning, a period of stratiform rainfall will likely persist for a
few hours.
Rainfall amounts averaging a little more than an inch in 6 hours
should be widespread. Isolated amounts of up to 2 inches are
possible. This rain could result in brief small stream flooding and
later rises on larger rivers. Any flooding that will occur should be
minor due to the fast nature of these storms. The rain will taper to
scattered showers Wednesday afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ WEDNESDAY FOR
INZ076>079-
083-084-089>092.
KY...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ WEDNESDAY FOR
KYZ023>032-
061-062-070>072.
WIND ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
KYZ033>043-
045>049-053>057-063>067-073>078-081-082.
$$
Mesoscale........MJ/MJP
Short Term.......RJS
Long Term........lg
Aviation.........RJP
Hydrology........CMC
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
847 PM EST THU JAN 31 2013
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION EARLY FRIDAY MORNING.
BLUSTERY AND COLD CONDITIONS ARE EXPECTED BEHIND THE COLD FRONT
ON FRIDAY. HIGH PRESSURE WILL BUILD OVERHEAD FRIDAY NIGHT INTO
SATURDAY BEFORE LOW PRESSURE IMPACTS THE AREA SATURDAY NIGHT INTO
SUNDAY. A SERIES OF CLIPPER SYSTEMS MAY IMPACT THE AREA EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE LONGWAVE UPPER-LEVEL TROUGH WILL REMAIN OVER THE REGION
TONIGHT THROUGH FRIDAY AND A CLIPPER LIKE SYSTEM IS EXPECTED TO
PASS THROUGH THE AREA LATE TONIGHT INTO EARLY FRIDAY MORNING. THE
SHORTWAVE ASSOCIATED WITH THE CLIPPER IS FAIRLY POTENT AND CAN BE
SEEN ON THE WATER VAPOR IMAGERY DIVING INTO THE MID-WEST/OHVLY THIS
EVENING. THERE WILL BE ENOUGH LIFT BOTH AT THE LOW-LEVELS AHEAD OF
THE COLD FRONT AND AT THE MID-LEVELS FOR A PERIOD OF LIGHT SNOW
TO MAKE IT THROUGH THE LOW-LEVEL DRY AIR...AFFECTING MOST
LOCATIONS. PCPN EVIDENT ON RGNL RADAR MOSAICS FM CVG-PAH ATTM.
18Z NAM SOLN AN OUTLIER PAINTING A STRIPE OF 0.10+ INCH QPF ACRS
DC METRO OVNGT-ELY FRI MRNG. MDL PHYSICS DO SUPPORT THE OUTPUT...
AS MAX LIFT COINCIDENT W/ DENDRITIC SNOW GROWTH ZONE. HWVR...18Z
GFS AND LTST RAP SNOW HALF THE QPF...AND LTST RUNS FM LCL WRFS
/ARW4 AND NMM12G/ SHOW A QUARTER THE QPF. WITH THAT IN MIND AS
WELL AS QUICK MVMT...AM DOUBTING THAT AN INCH OF SNW WL BE FOUND
BY FRI MRNG. TIMING DOES LOOK TO BE COINCIDENT WITH THE BGNG OF
RUSH HR...SO THAT DOESNT MEAN WE WL BE TROUBLE-FREE.
GUSTY NORTHWEST WINDS WILL MOVE IN BEHIND THE CLIPPER SYSTEM TOWARD
MORNING. WIND GUSTS AROUND 35 TO 40 MPH ARE EXPECTED. WIND GUSTS MAY
APPROACH WIND ADVISORY CRITERIA ACROSS THE HIGHER ELEVATIONS.
ANY STEADY LIGHT SNOW EAST OF THE ALLEGHENY HIGHLANDS SHOULD MOVE
OFF TO OUR EAST EARLY FRIDAY MORNING. BLUSTERY AND COLD CONDITIONS
ARE EXPECTED BEHIND THE COLD FRONT. MAX TEMPS WILL RANGE FROM THE
TEENS IN THE MOUNTAINS TO THE MIDDLE 30S IN LOWER SOUTHERN MARYLAND.
A FEW SNOW SHOWERS CANNOT BE RULED OUT ACROSS THE NORTHERN AND
WESTERN PORTIONS OF THE CWA...BUT LITTLE OR NO ACCUMULATION IS
EXPECTED.
FOR LOCATIONS ALONG AND WEST OF THE ALLEGHENY FRONT...SNOW SHOWERS
WILL CONTINUE THROUGH LATE THIS AFTERNOON. ACTIVITY WILL DIMINISH A
BIT THIS EVENING...BUT MORE SNOW IS EXPECTED OVERNIGHT AS THE
CLIPPER SYSTEM MOVES THROUGH. UPSLOPE SNOW SHOWERS WILL CONTINUE
FRIDAY. WILL CONTINUE WITH AN ADVISORY FOR AN ADDITIONAL 3 TO 5
INCHES OF SNOW THROUGH FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE BRIEFLY BUILDS IN FOR FRIDAY NIGHT...THEN MOVES
OFFSHORE ON SATURDAY. MODELS SHOW A SHORTWAVE TROUGH/VORT MAX MOVING
THROUGH SATURDAY NIGHT INTO EARLY SUNDAY. CYCLOGENESIS IS LIKELY TO
OCCUR OFF THE COAST ON SUNDAY...FAR ENOUGH OFFSHORE TO HAVE LITTLE
IMPACT ON THE IMMEDIATE CWA BUT THE SHORTWAVE ITSELF MAY BRING A
PERIOD OF LIGHT SNOW WITH LIGHT ACCUMULATIONS SATURDAY NIGHT INTO
EARLY SUNDAY. UPSLOPE SNOW IS LIKELY TO CONTINUE THROUGH THE DAY ON
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BOTH GFS AND ECMWF SHOW A TROUGHY PATTERN CONTINUING INTO EARLY NEXT
WEEK...WITH SHORTWAVES/VORT MAXES KEEPING CLOUDS AROUND AND ALSO A
CHANCE OF SNOW SHOWERS. THERE IS SOME UNCERTAINTY WITH THE TIMING OF
INDIVIDUAL MAXES WHICH WILL NEED TO BE RESOLVED WITH TIME.
THERE MAY BE A MID-WEEK BREAK /LATER WED INTO THU/ BUT LOW PRESSURE
COULD AFFECT THE CWA BY THE END OF THE WEEK.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED THROUGH THIS EVENING. NW WINDS STILL
GUSTING TO 25 KT. THESE GUSTS SHUD SUBSIDE OVNGT. A PERIOD OF
LIGHT SNOW WILL LIKELY IMPACT THE TERMINALS ELY FRI MRNG. BRIEF
PERIODS OF IFR CONDITIONS ARE POSSIBLE...ALTHO MVFR WL BE THE MORE
LKLY OUTCOME. GUSTY NORTHWEST WINDS WILL AFFECT THE TERMINALS
BEHIND THE COLD FRONT FRIDAY. GUSTS AROUND 35 KNOTS ARE EXPECTED.
HIGH PRESSURE OVER THE AREA FRIDAY NIGHT INTO EARLY SATURDAY MOVES
OFFSHORE. SHORTWAVE MAY BRING SOME LIGHT SNOW/RESTRICTIONS SATURDAY
NIGHT INTO EARLY SUNDAY AND UNSETTLED CONDITIONS COULD LINGER INTO
EARLY NEXT WEEK.
&&
.MARINE...
WINDS HV SUBSIDED SOMEWHAT THIS EVNG...AND THE TREND SHUD CONT
TNGT. WL CONT IDEA OF DROPPING TO SCA CONDS FOR THE OVNGT HRS. A
CLIPPER WL PASS ACRS THE WATERS ELY FRI MRNG...CAUSING BRIEF VSBY
REDUCTIONS.
MORE GUSTY WINDS ARE EXPECTED BEHIND THE COLD FRONT FRIDAY. A
GALE WARNING REMAINS IN EFFECT.
SCA CONDITIONS ARE EXPECTED TO LINGER INTO FRIDAY EVENING BUT AS
HIGH PRESSURE BUILDS IN WINDS SHOULD BE LESS AND BELOW ADVISORY
CRITERIA INTO THE FIRST PART OF THE WEEKEND. SCA CONDITIONS MAY
RETURN FOR SUNDAY.
&&
.HYDROLOGY...
SEVERAL RIVER FLOOD WARNINGS CONTINUE FOR THE POTOMAC RIVER BASIN AS
WELL AS THE RAPPAHANNOCK RIVER NEAR REMINGTON /WHICH HAS CRESTED AND
WILL FALL BELOW FLOOD STAGE TNGT/. SOME OF THE SMALLER TRIBUTARIES
OF THE POTOMAC SUCH AS THE MONOCACY RIVER...OPEQUON CREEK AND GOOSE
CREEK HAVE ALREADY CRESTED...AND WILL FALL BELOW FLOOD STAGE LATE
TNGT OR FRI MRNG. FLOOD WARNINGS FOR THE CACAPON RIVER AND THE
POTOMAC RIVER NEAR POINT OF ROCKS CONTINUE THRU FRI NGT AND SAT
RESPECTIVELY.
RELEASES FROM THE DUCKETT DAM HAVE BEEN DECREASING...RESULTING IN
RECEDING RIVER LEVELS IN THE PATUXENT NEAR LAUREL. FLOODING WILL
CONTINUE THIS EVE...AND THE FLOOD WARNING MAY NEED TO BE EXTENDED
FOR A FEW HRS.
&&
.TIDES/COASTAL FLOODING...
EFFECTS OF STRONG NW WINDS EVIDENT IN WATER LVLS. BLOWOUT CONDS
BEING REALIZED ATTM ACRS THE MARYLAND PORTION OF THE CHESAPEAKE
BAY AND TIDAL POTOMAC RIVER. ALL SITES CURRENTLY AOB ASTRO NORMS
AND STILL DROPPING. IT APPEARS AS THO SITES ALONG THE NRN BAY AND
UPR PTMC MAY NOT EVEN SEE A HIGH TIDE THIS EVENING.
HOWEVER...HEAVY RAINFALL YDA HAS CAUSED ELEVATED FRESHWATER
LEVELS IN THE POTOMAC RIVER UPSTREAM. THIS WILL HAVE AN IMPACT FOR
THE UPPER TIDAL POTOMAC...ESPECIALLY NEAR WISCONSIN AVENUE. MINOR
COASTAL FLOODING IS POSSIBLE DUE TO FRESHWATER IMPACTS LATE FRIDAY
THROUGH SATURDAY EVENING. AT THIS TIME...THE HIGHEST OF THESE
TIDES MAY BE SAT PM.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 6 PM EST FRIDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY UNTIL 6 PM EST FRIDAY FOR VAZ503.
WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST FRIDAY FOR WVZ501-503-
505.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>543.
GALE WARNING FROM 6 AM TO 6 PM EST FRIDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...BJL/BPP
NEAR TERM...BJL/HTS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...HTS/BJL/BPP
MARINE...HTS/BJL/BPP
HYDROLOGY...KLEIN
TIDES/COASTAL FLOODING...HTS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
821 PM EST THU JAN 31 2013
.SYNOPSIS...
A MID-LEVEL DISTURBANCE WILL BRING SNOW SHOWERS TO THE AREA
OVERNIGHT INTO FRIDAY. SCATTERED SNOW SHOWERS AND BLUSTERY
CONDITIONS WILL CONTINUE ACROSS THE AREA ON FRIDAY IN A COLD
WEST-NORTHWESTERLY FLOW. HIGH PRESSURE PASSING SOUTH OF THE AREA
WILL BRING A BRIEF RESPITE FRIDAY NIGHT BEFORE A CLIPPER SYSTEM
RETURNS ACCUMULATING SNOW FOR SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN EVENING UPDATE HAS BEEN ISSUED TO EXPAND THE WINTER WEATHER
ADVISORY NORTHWARD INTO THE RIDGES OF FAYETTE AND WESTMORELAND
COUNTIES IN PA.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A SHORT WAVE TROUGH
ACROSS CENTRAL ILLINOIS WITH VORT ENERGY EXTENDING UPSTREAM OF
THIS FEATURE ACROSS OHIO. AT 850MB...A NEAR ZONAL FLOW IS IN PLACE
WITH CAA ADVECTION ONGOING. 12Z KPIT SOUNDING INDICATES AN 850
TEMP OF -13C WITH THE RAP INDICATING A THERMAL TROUGH WITH -20C
TEMPS ADVECTING TOWARD THE AREA. AT THE SURFACE...A TROUGH AXIS
EXTENDS FROM WESTERN PA SOUTHWESTWARD INTO EASTERN KENTUCKY.
SCATTERED SNOW SHOWERS CONTINUE TO MOVE ACROSS THE UPPER OHIO
VALLEY. THE SURFACE TROUGH HAS CONTRIBUTED TO INCREASED COVERAGE
OF SNOW SHOWERS UPSTREAM IN SOUTHERN OHIO.
OVERNIGHT...THE MID-LEVEL SHORT WAVE WILL SWING ACROSS THE OHIO
VALLEY WITH SURFACE TROUGH EDGING EASTWARD INTO THE UPPER OHIO
VALLEY. THIS PAIR OF FEATURES WILL SERVE TO INCREASE SNOW SHOWER
COVERAGE AFTER 04Z FOR LOCATIONS ALONG AND SOUTH OF THE I-70
CORRIDOR. NORTHWARD COLD AIR ADVECTION WILL AND WEAKER WAVE ENERGY
ASSOCIATED WITH SHT WV WILL CONTRIBUTE TO CONTINUED SCATTERED SNOW
SHOWERS. FORECAST IS CLOSEST TO A SREF/NAM BLEND
OVERNIGHT...BRINGING AROUND A TENTH OF QPF TO LOCATIONS SOUTH OF
THE I-70 CORRIDOR. WITH THIS IN MIND...HAVE 1-2 INCHES FORECAST
FOR THE LOWLANDS WITH 1-3 INCHES WITH A BIT OF UPSLOPE ENHANCEMENT
FOR THE LAUREL HIGHLANDS/ALLEGHENY FRONT OF WV/MD/PA.
ELSEWHERE...GENERALLY AN INCH OR LESS OF SNOW IS FORECAST. FOR
TEMPS...A LAMP/HRRR BLEND WAS USED...WITH LOWS RANGING FROM NEAR
10 ACROSS THE RIDGES OF MD/WV TO THE UPPER TEENS IN THE LOWLANDS.
FRIDAY...THE INITIAL SHORT WAVE WILL SHIFT EAST OF THE AREA AND
THE LOW-LEVEL FLOW WILL BECOME MORE WEST-NORTHWESTERLY. 850 TEMPS
AROUND -18C ALONG WITH INVERSION HEIGHTS AROUND 9KFT WILL FAVOR
SCATTERED SNOW SHOWERS TO CONTINUE ACROSS THE AREA...WITH MORE OF
A FOCUS IN SNOW SQUALLS ACROSS THE I-80 CORRIDOR WITH LAKE EFFECT
AND ACROSS THE EASTERN RIDGES IN UPSLOPING. HAVE DECIDED TO DEFER
ON A LAKE EFFECT SNOW ADVISORY FOR THE I-80 CORRIDOR AS THE
INITIAL WAVE WILL PASS SOUTHWARD AND ADDITIONAL AMOUNTS OF 1-3
INCHES SEEM REASONABLE AT THIS TIME FOR RIDGES/LAKE EFFECT ZONES.
TEMPS WILL BE NEAR STEADY THROUGH THE DAY...IN THE MID TO UPPER
TEENS ACROSS THE LOWLANDS AND IN THE LOWER TO MID TEENS ACROSS THE
EASTERN RIDGES.
ANTICIPATE THAT THE BIGGEST PUBLIC IMPACTS ON FRIDAY WILL BE IN THE
MORNING WITH SNOW ACCUMULATION WITH THE WAVE SOUTH OF I-70 AND
SCATTERED SNOW SHOWERS LEADING TO SLICK ROADS ELSEWHERE. IN
ADDITION...WITH 15 TO 20 MPH WINDS AND GUSTS TO 30 MPH...WIND CHILLS
WILL BE NEAR ZERO AT TIMES ACROSS THE LOWLANDS AND SUB-ZERO AT
TIMES IN THE RIDGES.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A BREAK IN BETWEEN SYSTEMS FOR FRIDAY NIGHT WITH SNOW SHOWERS
ENDING AND CONTINUED QUITE COLD.
NEXT CLIPPER TYPE SYSTEM WILL ARRIVE SATURDAY WITH SOME
ACCUMULATING SNOW NOW LIKELY FOR SATURDAY INTO SATURDAY NIGHT.
SNOW SHOWERS WILL CONTINUE INTO SUNDAY AS SURFACE LOW INTENSIFIES
AS IT MOVES OFFSHORE. TEMPERATURES WILL REMAIN BELOW NORMAL
THROUGH THE WEEKEND.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS LOW PRESSURE MOVES OFF TO THE EAST...LAKE EFFECT SNOW WILL
DIMINISH AS DIRECTIONAL SHEAR INCREASES BETWEEN SURFACE AND 850MB.
WHILE THERE MAY BE A BRIEF BREAK IN PRECIPITATION MONDAY...00Z
GFS/ECMWF PLUS ENSEMBLES ARE IN GOOD AGREEMENT SHOWING A CLIPPER
MOVING ACROSS THE GREAT LAKES. THIS SHOULD BRING ANOTHER ROUND OF
SNOW MONDAY AFTERNOON INTO MONDAY NIGHT. PATTERN STILL LOOKS
UNSETTLED TUESDAY AND TUESDAY NIGHT WITH LESS MODEL AGREEMENT ABOUT
ANY PRECIPITATION DURING THAT TIME PERIOD. HIGH PRESSURE SHOULD MOVE
IN FOR WEDNESDAY AND THURSDAY...DRYING ALL LOCATIONS OUT. ANOTHER
SYSTEM DEVELOPING IN THE PLAINS SHOULD REMAIN TO THE WEST THROUGH
THURSDAY. TEMPERATURES WILL MODERATE SLIGHTLY...BUT STILL REMAIN
BELOW NORMAL THROUGHOUT THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
STRONG VORT MAX MOVG ACROSS THE OHIO VALLEY OVERNIGHT WILL BRING
OCCASIONAL MVFR TO BRIEF IFR RESTRICTIONS IN SNOW SHOWERS AT ALL
PORTS. PREVAILING VFR CONDITIONS CAN BE EXPECTED OUTSIDE THE SNOW
SHOWERS WITH GENERAL BKN TO OVC AROUND 4000 FT. AS THE SHORT WAVE
MOVES EAST OF THE DISTRICT AROUND DAYBREAK...SNOW SHOWERS WILL TAPER
TO JUST A FEW MORNING FLURRIES. GENERAL VFR CONDITIONS CAN BE
EXPECTED AT MOST PORTS THROUGH THE DAY FRIDAY. SNOW SHOWERS MAY
PERSIST A BIT LONGER INTO THE MORNING AT KFKL AND KDUJ.
.OUTLOOK.../FRIDAY THROUGH MONDAY/...
OCCASIONAL RESTRICTIONS ARE EXPECTED THROUGH THE PERIOD IN SCATTERED
SNOW SHOWERS AS SEVERAL FAST MOVING DISTURBANCES MOVE THROUGH THE
GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...RSD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
649 AM EST WED JAN 30 2013
.SYNOPSIS...
WELL ABOVE NORMAL TEMPERATURES...GUSTY WINDS AND RAIN SHOWERS
TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL PASS THROUGH LATE
THIS AFTERNOON AND EVENING. MUCH COLDER AIR AND SNOW SHOWERS FOR
THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WILL ISSUE A WIND ADVISORY TODAY FOR THE HIGHEST RIDGES IN
GARRETT...PRESTON AND TUCKER COUNTIES. LATEST RUC FORECAST
SOUNDINGS ON BUFKIT ARE SHOWING 60-65KTS TODAY JUST ABOVE 2500FT
IN THESE COUNTIES.
PER HPC DESIGNATION OF MOD RISK FOR EXCESSIVE RAINFALL AND
COUNTIES WITH THE LOWEST FFG...WILL ISSUE FLOOD WATCH FOR PORTIONS
OF THE SOUTH AND EAST TODAY AND TONIGHT.
STRONG COLD FRONT WILL MOVE INTO W OHIO AFTER DAWN. SHOWERS AND
SOME STORMS WILL ACCOMPANY THE FRONT AS IT CONTINUES ITS SLOW
EASTWARD PROGRESSION. EXPECT A GOOD SOAKING TODAY WITH ONE- HALF
TO ONE INCH OF RAIN FOR MUCH OF THE REGION. IN THE FLOOD WATCH
COUNTIES...1 TO 2 INCHES OF RAIN IS POSSIBLE WITH THE BULK OF IT
COMING THIS AFTERNOON AND EVENING. THE WATCH MAY NEED TO BE
EXPANDED PARTICULARLY IF A LINE OF STRONG SLOW MOVING CONVECTION
DEVELOPS.
THE OTHER PROBLEM WILL BE THE POTENTIAL FOR STRONG WIND GUSTS
ACROSS THE REST OF MY COUNTIES. LATEST CONVECTIVE OUTLOOK FOR
TODAY PUT MUCH OF THE AREA IN A SLIGHT RISK. THINK THE BEST WAY TO
HANDLE THIS IS TO INCLUDE THE POSSIBILITY OF SEVERE STORMS TODAY
WITH DAMAGING WINDS.
TEMPS WILL REMAIN WELL ABOVE NORMAL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
MUCH COLDER AIR WILL RAPIDLY MOVE IN TONIGHT. LEFT OVER RAIN
SHOWERS WILL CHANGE OVER TO SNOW SHOWERS AS THE NIGHT PROGRESSES.
THINK THE BEST LOCATION FOR ANY ACCUMULATIONS WILL BE ACROSS THE
HIGHER ELEVATIONS. IT DOES NOT APPEAR THAT THE SFC TEMPS WILL
RESPOND QUICK ENOUGH ELSEWHERE TO ALLOW FOR ACCUMULATION.
CONCERNED ABOUT DAMAGING WINDS BEHIND THE FRONT AS WELL. VERY
STRONG CAA...COMBINED WITH PRES RISES OF 6 TO 8 MBS IS PRESENTING
A PERIOD OVERNIGHT THAT MAY REQUIRE A WIND ADVISORY. WILL ALLOW
THE NEXT SHIFT TO TAKE A CLOSER LOOK AT THIS.
RISK FOR SNOW SHOWERS...MAINLY OVER THE FAR NORTH AND
RIDGES...WILL CONTINUE THROUGH THE THURSDAY. TEMPERATURES WILL BE
STEADY OR SLOWLY FALLING WITH GUSTY WINDS CONTINUING.
AT THIS POINT...HAVE VERY LOW CONFIDENCE ON EFFECTS FROM SHORTWAVE
WHICH WILL DIVE SOUTHWARD ACROSS THE REGION THU NIGHT. LATEST
MODEL RUNS ARE HINTING AT SOME ACCUMULATING SNOWS...PARTICULARLY
OVER THE SOUTHERN HALF. THU NIGHT/FRI MORN FORECAST WILL NEED FINE
TUNING AS MODELS GET BETTER HANDLE ON LOCATION OF WAVE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
UNCERTAINTY LIES IN THE FORECAST AS MODELS SEEM TO BE IN
DISAGREEMENT. GFS/ECMWF DO SHOW A SHORTWAVE TROUGH MOVING OVER THE
AREA ON THE WEEKEND AND THUS BRINGING A CLIPPER SOUTHEAST WITH THE
GFS BRINGING HIGHER AMOUNTS OF SNOW THAN THE ECMWF. POSSIBLE LAKE
ENHANCED AND/OR TERRAIN ENHANCED SNOW COULD DEVELOP AFTER THE
PASSAGE OF THE QUICK MOVING SYSTEM.
THE GFS BRINGS IN ANOTHER STRONGER CLIPPER OVER THE GREAT LAKES AND
NORTHERN OHIO VALLEY MONDAY NIGHT INTO TUESDAY WHILE THE ECMWF
TRACKS THE SYSTEM MORE NORTHEAST AND BRINGS PRECIPITATION TO OUR AREA
ALONG A COLD FRONT. HIGH PRESSURE BUILDS BEHIND THE SYSTEM LEAVING
THE MID WEEK DRY. HPC TRENDED TOWARDS THE ECMWF RUN THE LATTER PART
OF THE EXTENDED AND THUS FORECAST IS BASED ON GFS/HPC GUIDANCE KEEPING
SLIGHT TO CHANCE POPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR WL DCRS TO MVFR IN SHRA LT MRNG INTO THIS AFTN AS A STG CDFNT
APRCHS FM THE W. SHRA EXTEND WELL OUT AHEAD OF THE FNT. SHOULD
SEE ADDNL DVLPMNT ALG THE FNT THIS AFTN. STLT/MESO/RAOB INSTAB
CHARTS SHOW SOME INSTAB ALG/AHD OF THE FNT. COULD SEE A TS AT ANY
OF THE SITES ESP S OF I-80 THIS AFTN BUT DUE TO PLENTY OF
UNCERTAINTY IN INSTAB/TIMING HAVE KEPT THEM OUT OF THE TAFS ATTM.
INCLUDED A TEMPO FOR +SHRA AND STG WND GUSTS AT ZZV LT MRNG. THIS
MAY HAVE TO BE ADDED TO OTHER SITES AS WELL IN LTR FCSTS. STG LLVL
JET WL KEEP THE THREAT OF LLWS ACRS THE RGN THRU THIS MRNG.
FROPA/WSHFT TO THE W EXPD THIS EVE WITH MVFR CONDS CONTG. EVEN A
FEW SHSN PSBL OVRNGT.
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
PERIODIC RESTRICTION ARE EXPD THRU THE PD AS SVRL DISTURBANCES
MOVE THRU IN COLD W-NW FLOW. GUSTY W WNDS ARE ALSO EXPTD THU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR MDZ001.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ016-023-031-073>076.
WV...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR WVZ012-021>023-041.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
629 AM EST WED JAN 30 2013
.SYNOPSIS...
LOW PRESSURE IS CENTERED THIS MORNING OVER MICHIGAN. FROM THIS A
WARM EXTENDS ALONG THE MASON-DIXON LINE WHILE A COLD FRONT
EXTENDS FROM INDIANA TO ARKANSAS. THE COLD FRONT WILL MOVE THROUGH
THE MID ATLANTIC STATES THIS EVENING. ANOTHER COLD FRONT WILL MOVE
THROUGH THE REGION FRIDAY...FOLLOWED BY HIGH PRESSURE SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 11Z...WARM FRONT IS JUST SOUTH OF THE MASON-DIXON LINE. A COLD
FRONT IS THROUGH CHICAGO WITH A PREFRONTAL BAND OF HEAVY SHOWERS
ASSOCIATED WITH A STRONG GULF PLUME THAT EXTENDS FROM BATON ROUGE
TO CINCINNATI. A WIDE SWATH OF TRAILING STRATIFORM IS OVER WRN IL
AND IN.
THIS COLD FRONT AND PREFRONTAL ACTIVITY WILL PROGRESS EAST TOWARD
THE MID-ATLANTIC THROUGH TODAY. THE 08Z HRRR HAS SLOWED THE CURRENT
PREFRONTAL BAND...REACHING THE ALLEGHENY FRONT AROUND 20Z WHICH
SEEMS TO BE A REASONABLE TIMEFRAME. FLASH FLOOD WATCH IS IN
EFFECT FOR COUNTIES ALONG THE ALLEGHENY FRONT AS WELL AS
HAMPSHIRE/HARDY WHERE 6 HR FLASH FLOOD GUIDANCE IS AROUND AN INCH
/1-2 INCHES ARE EXPECTED FOR THOSE COUNTIES/. ANY OTHER FLOODING
LOOKS TO BE IN URBAN AREAS LIKE BALT-WASH. OTHERWISE A WELCOME
HEAVY RAINFALL THOUGH DAMAGING WINDS ARE A REAL THREAT.
SEVERE THREAT. VERY STRONG SHEAR/SLY LLJ AND VERY LOW CAPE WILL
RESULT IN A DYNAMIC BAND/QLCS LINE SPREADING EAST ACROSS THE CWA
LATER THIS AFTERNOON THROUGH THE EVENING HOURS. GUSTS IN EXCESS OF
50 KT POSSIBLE WITH THIS BAND ACROSS THE LWX CWA. KEPT THUNDER
CHANCES AT JUST CHANCE THOUGH THE MIDWEST HAS HAD A FAIR SHARE OF
THUNDER TONIGHT. THIS COLD FRONT MAY FORM AN AXIS FOR BOTH HEAVY
RAIN AND TORNADOES. STRONG LOW LEVEL WIND SHEAR WILL ALLOW FOR
HORIZONTAL VORTICITY ROLLS. THE WARM FRONT AND A FEW MILES INTO
THE COLD SIDE ARE TEXTBOOK PRIME AREAS FOR TORNADOES. PROGRESSION
OF THIS WARM FRONT TODAY WILL BE KEY.
WIND. A STRONG LLJ AHEAD OF THIS FRONT WILL INCREASE OVERHEAD
THROUGH THE DAY. A WIND ADVISORY IS IN EFFECT FOR MAJOR RIDGELINES
BLUE RIDGE AND WEST FROM NOON THROUGH TONIGHT. WIND SHIFT TO WEST
WITH FRONT WILL OCCUR SHORTLY AFTER MIDNIGHT. AS OF NOW WLY FLOW
LOOKS TO BE BELOW 40 KT GUSTS...SO LATER SHIFTS WILL HAVE TO HONE IN
ON IF THERE IS A WIND THREAT FOR LATE TONIGHT/THURSDAY MORNING.
TEMPERATURES. WARM AHEAD OF THE COLD FRONT WITH UPR 50S OUT THERE
NOW EASILY REACHING THE UPR 60S/LOW 70S BEFORE PREFRONTAL
PRECIP/CLOUDS LIMIT INCREASES. 850MB TEMPS ARE NEAR 12C...SO MID 70S
WOULD BE POSSIBLE IN SUNNY CONDITIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WARM EVENING AHEAD OF THE PREFRONTAL RAIN BANDS. PRECIP SLOWLY
CUTS OF WITH STRATIFORM TRAILING MAIN BAND FOR A FEW HOURS.
UPSLOPE SNOW OF ONLY A COUPLE INCHES. NO WINTER WEATHER ADVISORY
EXPECTED. WITH COLD AIR ADVECTION...MIN TEMPS TONIGHT WILL BE
SIMILAR TO THE HIGH TEMPS FOR THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AFTR TUE AND TDA`S VERY WARM TEMPS THE RGN WL RETURN TO MORE
NORMAL LATE JAN/ERLY FEB TEMPS FOR THE XTND PD.
BRZY/WINDY WL BE THE OPERATIVE WORDS FOR THU AS HIGH PRES BUILDS
INTO THE RGN. TEMPS THU WL BE 25 DEGS COOLER THAN TDA. UPSLOPE
SNSH WL ALSO BE A CONCERN W/ SVRL INCHES OF ACCUM PSBL IN THE
HIGHLANDS. AM ADVSRY MAY BE REQUIRED.
HIGH PRES WL BUILD INTO THE RGN FRI AFTN AND SAT. HIGHS GNRLY IN
THE U30S E OF THE MTNS. LOWS IN THE 20S.
UPPER-LEVEL DISTURBANCES WILL BRING A CHANCE FOR SNOW SHOWERS...W/
THE BEST CHCS BEING ACROSS THE NORTHERN AND WESTERN CWA. DURG THE
XTND PD FAST UPR LVL WL PREVAIL..AND W/ THIS IS THE PTNL FOR MORE
ALBERTA CLIPPERS. A DISTURBANCE WILL PASS THROUGH SATURDAY NIGHT.
ANOTHER MAY IMPACT THE AREA TUE.
HIGHS CONT IN THE U30S/L40S SUN THRU TUE. LOWS IN THE MU20S.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
MVFR CIGS SPREADING NORTH FROM SRN VA HAVE CROSSED IAD AND WILL
MOVE ACROSS THE DC METRO THROUGH THE MID MORNING HOURS. SLY LOW
LEVEL WIND SHEAR INCREASES TODAY PEAKING TONIGHT JUST AHEAD OF A
COLD FRONT. CHANCES FOR THUNDER WITH VERY GUSTY WINDS AND HEAVY
RAINFALL...ON THE ORDER OF 50 KT. WINDS SHIFT WEST AND DECREASE
LATE TONIGHT.
GUSTY NW WINDS XPCTD THU. SKIES/CIGS SHOULD BE VFR. VFR CONDITIONS
ARE EXPECTED MOST OF THE TIME THU NIGHT THROUGH SUNDAY.
&&
.MARINE...
SLY GALE EXPECTED BY LATE AFTERNOON CONTINUING UNTIL THE COLD FRONT
CROSSES LATE TONIGHT.
HIGH PRES BLDG INTO THE WATERS WL LKLY CONT TO CAUSE STRONG WIND
GUSTS DURG THU. HV ISSUED A GALE WRNG FOR CHES BAY/LWR TIDAL
PTMC...AND A STRONG SCA FOR THE RMDR OF THE WATERS.
A COLD FRONT WILL PASS THROUGH THURSDAY NIGHT, GUSTY WINDS ARE
EXPECTED BEHIND THE FRONT FRIDAY. HIGH PRES OVR THE WATERS SAT.
ANOTHER COLD FRONT MAY IMPACT THE WATERS SUNDAY.
&&
.TIDES/COASTAL FLOODING...
COASTAL FLOOD ADVISORY IN EFFECT THIS EVENING AND TONIGHT FOR ANNE
ARUNDEL AND NORTH...AND DC/ALEXANDRIA. A SOUTHERLY FLOW WILL
INCREASE TODAY WITH GUSTS AROUND 35 KNOTS DURING THE AFTERNOON AND
EVENING HOURS. THE STRONG SOUTHERLY FLOW WILL PUSH WATER UP THE
CHESAPEAKE BAY AND THE TIDAL POTOMAC RIVER UNTIL THE COLD FRONT
PASSES LATE TONIGHT. SINCE THE FLOW WILL BE SLY ONLY THE WATER IN
THE BAY IS EXPECTED TO SURGE NORTHWARD. HAD THIS BEEN A
SOUTHEASTERLY GALE...THEN ADDED WATER WOULD LIKELY CAUSE MODERATE
FLOODING. WIND SHOULD BE STRONG ENOUGH TO CAUSE WIDESPREAD MINOR
INUNDATION BEFORE HIGH TIDE...THEN CONTINUE UNTIL THE COLD
FRONT...NOT NECESSARILY ONLY NEAR HIGH TIDE. LATER SHIFTS WILL
HAVE TO MONITOR WATER RISE FROM LOWER PARTS OF THE BAY.
NW WINDS WILL ALLOW FOR TIDAL ANOMALIES TO DECREASE THU.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY FROM 7 PM THIS EVENING TO 3 AM EST
THURSDAY FOR DCZ001.
MD...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR MDZ501.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR MDZ501-502.
COASTAL FLOOD ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
THURSDAY FOR MDZ007-011-014.
VA...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR
VAZ025>030-036>040-503-504.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR VAZ503-504.
COASTAL FLOOD ADVISORY FROM 7 PM THIS EVENING TO 3 AM EST
THURSDAY FOR VAZ054.
WV...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR WVZ050-
055-501>503-505-506.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR WVZ050-055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 PM EST THURSDAY FOR
ANZ533-534-537-541>543.
&&
$$
UPDATE...JACKSON
PREVIOUS DISCUSSION...JACKSON/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
454 AM EST WED JAN 30 2013
.SYNOPSIS...
LOW PRESSURE IS CENTERED OVER MICHIGAN. FROM THIS A WARM EXTENDS
ACROSS PENNSYLVANIA WHILE A COLD FRONT EXTENDS FROM INDIANA TO
ARKANSAS. THE COLD FRONT WILL MOVE THROUGH THE MID ATLANTIC STATES
THIS EVENING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION
FRIDAY...FOLLOWED BY HIGH PRESSURE SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...COLD FRONT IS OVER THE UPR MIDWEST WITH A PREFRONTAL
BAND OF THUNDERSTORMS ASSOCIATED WITH A STRONG GULF PLUME EXTENDS
FROM THE MS DELTA TO DETROIT. A WIDE SWATH OF TRAILING STRATIFORM
IS OVER WRN IL AND IN.
THIS COLD FRONT AND PREFRONTAL ACTIVITY WILL PROGRESS EAST THROUGH
TODAY. THE 05Z HRRR DOES PLACE THE PREFRONTAL BAND AT THE ALLEGHENY
FRONT BY 18Z...LESS THAN 10 HRS. THAT IS QUITE FAST...WITH 20Z
SEEMINGLY A BETTER GUESS AS OF NOW. FLASH FLOOD WATCH IS IN EFFECT
FOR COUNTIES ALONG THE ALLEGHENY FRONT AS WELL AS HAMPSHIRE/HARDY
WHERE 6 HR FLASH FLOOD GUIDANCE IS AROUND AN INCH /1-2 INCHES ARE
EXPECTED FOR THOSE COUNTIES/. ANY OTHER FLOODING LOOKS TO BE IN
URBAN AREAS LIKE BALT-WASH. OTHERWISE A WELCOME HEAVY RAINFALL.
SEVERE THREAT. VERY STRONG SHEAR AND VERY LOW CAPE WILL RESULT IN A
DYNAMIC BAND. GUSTS AROUND 50 KT POSSIBLE WITH THIS BAND ACROSS THE
LWX CWA. KEPT THUNDER CHANCES AT JUST CHANCE THOUGH THE MIDWEST HAS
HAD A FAIR SHARE OF THUNDER TONIGHT.
WIND. A STRONG LLJ AHEAD OF THIS FRONT WILL INCREASE OVERHEAD
THROUGH THE DAY. A WIND ADVISORY IS IN EFFECT FOR MAJOR RIDGELINES
BLUE RIDGE AND WEST FROM NOON THROUGH TONIGHT. WIND SHIFT TO WEST
WITH FRONT WILL OCCUR SHORTLY AFTER MIDNIGHT. AS OF NOW WLY FLOW
LOOKS TO BE BELOW 40 KT GUSTS...SO LATER SHIFTS WILL HAVE TO HONE IN
ON IF THERE IS A WIND THREAT FOR LATE TONIGHT/THURSDAY MORNING.
TEMPERATURES. WARM AHEAD OF THE COLD FRONT WITH UPR 50S OUT THERE
NOW EASILY REACHING THE UPR 60S/LOW 70S BEFORE PREFRONTAL
PRECIP/CLOUDS LIMIT INCREASES. 850MB TEMPS ARE NEAR 12C...SO MID 70S
WOULD BE POSSIBLE IN SUNNY CONDITIONS.
&&
.SHORT TERM /TONIGHT/...
PRECIP SLOWLY CUTS OF WITH STRATIFORM TRAILING MAIN BAND
FOR A FEW HOURS. UPSLOPE SNOW OF ONLY A COUPLE INCHES. NO WINTER
ADVISORY EXPECTED.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AFTR TUE AND TDA`S VERY WARM TEMPS THE RGN WL RETURN TO MORE
NORMAL LATE JAN/ERLY FEB TEMPS FOR THE XTND PD.
BRZY/WINDY WL BE THE OPERATIVE WORDS FOR THU AS HIGH PRES BUILDS
INTO THE RGN. TEMPS THU WL BE 25 DEGS COOLER THAN TDA. UPSLOPE
SNSH WL ALSO BE A CONCERN W/ SVRL INCHES OF ACCUM PSBL IN THE
HIGHLANDS. AM ADVSRY MAY BE REQUIRED.
HIGH PRES WL BUILD INTO THE RGN FRI AFTN AND SAT. HIGHS GNRLY IN
THE U30S E OF THE MTNS. LOWS IN THE 20S.
UPPER-LEVEL DISTURBANCES WILL BRING A CHANCE FOR SNOW SHOWERS...W/
THE BEST CHCS BEING ACROSS THE NORTHERN AND WESTERN CWA. DURG THE
XTND PD FAST UPR LVL WL PREVAIL..AND W/ THIS IS THE PTNL FOR MORE
ALBERTA CLIPPERS. A DISTURBANCE WILL PASS THROUGH SATURDAY NIGHT.
ANOTHER MAY IMPACT THE AREA TUE.
HIGHS CONT IN THE U30S/L40S SUN THRU TUE. LOWS IN THE MU20S.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
IFR STILL POSSIBLE THROUGH MID MORNING. SLY LOW LEVEL WIND SHEAR
INCREASES TODAY PEAKING TONIGHT JUST AHEAD OF A COLD FRONT. CHANCES
FOR THUNDER WITH VERY GUSTY WINDS...ON THE ORDER OF 50 KT. WINDS
SHIFT WEST AND DECREASE LATE TONIGHT.
GUSTY NW WINDS XPCTD THU. SKIES/CIGS SHOULD BE VFR. VFR CONDITIONS
ARE EXPECTED MOST OF THE TIME THU NIGHT THROUGH SUNDAY.
&&
.MARINE...
SLY GALE EXPECTED BY LATE AFTERNOON CONTINUING UNTIL THE COLD FRONT
CROSSES LATE TONIGHT.
HIGH PRES BLDG INTO THE WATERS WL LKLY CONT TO CAUSE STRONG WIND
GUSTS DURG THU. HV ISSUED A GALE WRNG FOR CHES BAY/LWR TIDAL
PTMC...AND A STRONG SCA FOR THE RMDR OF THE WATERS.
A COLD FRONT WILL PASS THROUGH THURSDAY NIGHT, GUSTY WINDS ARE
EXPECTED BEHIND THE FRONT FRIDAY. HIGH PRES OVR THE WATERS SAT.
ANOTHER COLD FRONT MAY IMPACT THE WATERS SUNDAY.
&&
.TIDES/COASTAL FLOODING...
A SOUTHERLY FLOW WILL INCREASE TODAY WITH GUSTS AROUND 35 KNOTS
DURING THE AFTERNOON AND EVENING HOURS. THE STRONG SOUTHERLY FLOW
WILL PUSH WATER UP THE MARYLAND PORTION OF THE CHESAPEAKE BAY AND
THE TIDAL POTOMAC RIVER. DESPITE THE LOW ASTRONOMICAL
NORMS...MODERATE FLOODING IS LIKELY NEAR TIMES OF HIGH TIDE
WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. A COASTAL FLOOD
ADVSIROY HAS BEEN ISSUED FOR DC AND WRN SIDE OF CHES BAY FM ANNE
ARUNDEL NWD.
NW WINDS WILL ALLOW FOR TIDAL ANOMALIES TO DECREASE THU.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY FROM 7 PM THIS EVENING TO 3 AM EST
THURSDAY FOR DCZ001.
MD...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR MDZ501.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR MDZ501-502.
COASTAL FLOOD ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
THURSDAY FOR MDZ007-011-014.
VA...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR
VAZ025>030-036>040-503-504.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR VAZ503-504.
COASTAL FLOOD ADVISORY FROM 7 PM THIS EVENING TO 3 AM EST
THURSDAY FOR VAZ054.
WV...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR WVZ050-
055-501>503-505-506.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR WVZ050-055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 PM EST THURSDAY FOR
ANZ533-534-537-541>543.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
409 AM EST WED JAN 30 2013
.SYNOPSIS...
WELL ABOVE NORMAL TEMPERATURES...GUSTY WINDS AND RAIN SHOWERS
TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL PASS THROUGH LATE
THIS AFTERNOON AND EVENING. MUCH COLDER AIR AND SNOW SHOWERS FOR
THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WILL ISSUE A WIND ADVISORY TODAY FOR THE HIGHEST RIDGES IN
GARRETT...PRESTON AND TUCKER COUNTIES. LATEST RUC FORECAST
SOUNDINGS ON BUFKIT ARE SHOWING 60-65KTS TODAY JUST ABOVE 2500FT
IN THESE COUNTIES.
PER HPC DESIGNATION OF MOD RISK FOR EXCESSIVE RAINFALL AND
COUNTIES WITH THE LOWEST FFG...WILL ISSUE FLOOD WATCH FOR PORTIONS
OF THE SOUTH AND EAST TODAY AND TONIGHT.
STRONG COLD FRONT WILL MOVE INTO W OHIO AFTER DAWN. SHOWERS AND
SOME STORMS WILL ACCOMPANY THE FRONT AS IT CONTINUES ITS SLOW
EASTWARD PROGRESSION. EXPECT A GOOD SOAKING TODAY WITH ONE- HALF
TO ONE INCH OF RAIN FOR MUCH OF THE REGION. IN THE FLOOD WATCH
COUNTIES...1 TO 2 INCHES OF RAIN IS POSSIBLE WITH THE BULK OF IT
COMING THIS AFTERNOON AND EVENING. THE WATCH MAY NEED TO BE
EXPANDED PARTICULARLY IF A LINE OF STRONG SLOW MOVING CONVECTION
DEVELOPS.
THE OTHER PROBLEM WILL BE THE POTENTIAL FOR STRONG WIND GUSTS
ACROSS THE REST OF MY COUNTIES. LATEST CONVECTIVE OUTLOOK FOR
TODAY PUT MUCH OF THE AREA IN A SLIGHT RISK. THINK THE BEST WAY TO
HANDLE THIS IS TO INCLUDE THE POSSIBILITY OF SEVERE STORMS TODAY
WITH DAMAGING WINDS.
TEMPS WILL REMAIN WELL ABOVE NORMAL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
MUCH COLDER AIR WILL RAPIDLY MOVE IN TONIGHT. LEFT OVER RAIN
SHOWERS WILL CHANGE OVER TO SNOW SHOWERS AS THE NIGHT PROGRESSES.
THINK THE BEST LOCATION FOR ANY ACCUMULATIONS WILL BE ACROSS THE
HIGHER ELEVATIONS. IT DOES NOT APPEAR THAT THE SFC TEMPS WILL
RESPOND QUICK ENOUGH ELSEWHERE TO ALLOW FOR ACCUMULATION.
CONCERNED ABOUT DAMAGING WINDS BEHIND THE FRONT AS WELL. VERY
STRONG CAA...COMBINED WITH PRES RISES OF 6 TO 8 MBS IS PRESENTING
A PERIOD OVERNIGHT THAT MAY REQUIRE A WIND ADVISORY. WILL ALLOW
THE NEXT SHIFT TO TAKE A CLOSER LOOK AT THIS.
RISK FOR SNOW SHOWERS...MAINLY OVER THE FAR NORTH AND
RIDGES...WILL CONTINUE THROUGH THE THURSDAY. TEMPERATURES WILL BE
STEADY OR SLOWLY FALLING WITH GUSTY WINDS CONTINUING.
AT THIS POINT...HAVE VERY LOW CONFIDENCE ON EFFECTS FROM SHORTWAVE
WHICH WILL DIVE SOUTHWARD ACROSS THE REGION THU NIGHT. LATEST
MODEL RUNS ARE HINTING AT SOME ACCUMULATING SNOWS...PARTICULARLY
OVER THE SOUTHERN HALF. THU NIGHT/FRI MORN FORECAST WILL NEED FINE
TUNING AS MODELS GET BETTER HANDLE ON LOCATION OF WAVE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
UNCERTAINTY LIES IN THE FORECAST AS MODELS SEEM TO BE IN
DISAGREEMENT. GFS/ECMWF DO SHOW A SHORTWAVE TROUGH MOVING OVER THE
AREA ON THE WEEKEND AND THUS BRINGING A CLIPPER SOUTHEAST WITH THE
GFS BRINGING HIGHER AMOUNTS OF SNOW THAN THE ECMWF. POSSIBLE LAKE
ENHANCED AND/OR TERRAIN ENHANCED SNOW COULD DEVELOP AFTER THE
PASSAGE OF THE QUICK MOVING SYSTEM.
THE GFS BRINGS IN ANOTHER STRONGER CLIPPER OVER THE GREAT LAKES AND
NORTHERN OHIO VALLEY MONDAY NIGHT INTO TUESDAY WHILE THE ECMWF
TRACKS THE SYSTEM MORE NORTHEAST AND BRINGS PRECIPITATION TO OUR AREA
ALONG A COLD FRONT. HIGH PRESSURE BUILDS BEHIND THE SYSTEM LEAVING
THE MID WEEK DRY. HPC TRENDED TOWARDS THE ECMWF RUN THE LATTER PART
OF THE EXTENDED AND THUS FORECAST IS BASED ON GFS/HPC GUIDANCE KEEPING
SLIGHT TO CHANCE POPS.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
VFR EXPD OVRNGT. LLVL JET SPEEDS WL BE INCRG OVRNGT AS WELL...WITH
LLWS CONTG INTO WED MRNG. A STG CDFNT WL APRCH FM THE W WED...
BRINGING MVFR SHRA AND GUSTY S WNDS. SOME INSTAB EVIDENT UPSTREAM
TNGT LOOKING AT STLT/MESO/RAOB INSTAB CHART DATA. THIS SHOULD
TRANSITION EWD WED WITH THE CDFNT. TS WL BE PSBL ALG/AHEAD OF THE
CDFNT BUT LEFT OUT OF TAFS FOR NOW WITH RELATIVELY LOW PROB OF
OCCURRANCE AT ANY ONE POINT. WL RE-EVALUATE FOR LTR TAFS. EXPT
INITIAL WSHFT TO SW WITH PREFRONTAL TROF LT AFTN...THEN TO THE W
WED EVE/NGT AS THE CDFNT MOVES THRU. WNDS WL BE GUSTY AS WELL
BEHIND THE FNT.
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
PERIODIC RESTRICTION ARE EXPD THRU THE PD AS SVRL DISTURBANCES
MOVE THRU IN COLD W-NW FLOW. GUSTY W WNDS ARE ALSO EXPTD THRU THU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR MDZ001.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ016-023-031-073>076.
WV...FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR WVZ012-021>023-041.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
400 AM EST WED JAN 30 2013
.SYNOPSIS...
LOW PRESSURE IS CENTERED OVER MICHIGAN. FROM THIS A WARM EXTENDS
ACROSS PENNSYLVANIA WHILE A COLD FRONT EXTENDS FROM INDIANA TO
ARKANSAS. THE COLD FRONT WILL MOVE THROUGH THE MID ATLANTIC STATES
THIS EVENING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION
FRIDAY...FOLLOWED BY HIGH PRESSURE SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...COLD FRONT IS OVER THE UPR MIDWEST WITH A PREFRONTAL
BAND OF THUNDERSTORMS ASSOCIATED WITH A STRONG GULF PLUME EXTENDS
FROM THE MS DELTA TO DETROIT. A WIDE SWATH OF TRAILING STRATIFORM IS
OVER WRN IL AND IN.
THIS COLD FRONT AND PREFRONTAL ACTIVITY WILL PROGRESS EAST THROUGH
TODAY. THE 05Z HRRR DOES PLACE THE PREFRONTAL BAND AT THE ALLEGHENY
FRONT BY 18Z...LESS THAN 10 HRS. THAT IS QUITE FAST...WITH 20Z
SEEMINGLY A BETTER GUESS AS OF NOW. FLASH FLOOD WATCH IS IN EFFECT
FOR COUNTIES ALONG THE ALLEGHENY FRONT AS WELL AS HAMPSHIRE/HARDY
WHERE 6 HR FLASH FLOOD GUIDANCE IS AROUND AN INCH /1-2 INCHES ARE
EXPECTED FOR THOSE COUNTIES/. ANY OTHER FLOODING LOOKS TO BE IN
URBAN AREAS LIKE BALT-WASH. OTHERWISE A WELCOME HEAVY RAINFALL.
SEVERE THREAT. VERY STRONG SHEAR AND VERY LOW CAPE WILL RESULT IN A
DYNAMIC BAND. GUSTS AROUND 50 KT POSSIBLE WITH THIS BAND ACROSS THE
LWX CWA. KEPT THUNDER CHANCES AT JUST CHANCE THOUGH THE MIDWEST HAS
HAD A FAIR SHARE OF THUNDER TONIGHT.
WIND. A STRONG LLJ AHEAD OF THIS FRONT WILL INCREASE OVERHEAD
THROUGH THE DAY. A WIND ADVISORY IS IN EFFECT FOR MAJOR RIDGELINES
BLUE RIDGE AND WEST FROM NOON THROUGH TONIGHT. WIND SHIFT TO WEST
WITH FRONT WILL OCCUR SHORTLY AFTER MIDNIGHT. AS OF NOW WLY FLOW
LOOKS TO BE BELOW 40 KT GUSTS...SO LATER SHIFTS WILL HAVE TO HONE IN
ON IF THERE IS A WIND THREAT FOR LATE TONIGHT/THURSDAY MORNING.
TEMPERATURES. WARM AHEAD OF THE COLD FRONT WITH UPR 50S OUT THERE
NOW EASILY REACHING THE UPR 60S/LOW 70S BEFORE PREFRONTAL
PRECIP/CLOUDS LIMIT INCREASES. 850MB TEMPS ARE NEAR 12C...SO MID 70S
WOULD BE POSSIBLE IN SUNNY CONDITIONS.
&&
.SHORT TERM /TONIGHT/...
PRECIP SLOWLY CUTS OF WITH STRATIFORM TRAILING MAIN BAND
FOR A FEW HOURS. UPSLOPE SNOW OF ONLY A COUPLE INCHES. NO WINTER
ADVISORY EXPECTED.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AFTR TUE AND TDA`S VERY WARM TEMPS THE RGN WL RETURN TO MORE
NORMAL LATE JAN/ERLY FEB TEMPS FOR THE XTND PD.
BRZY/WINDY WL BE THE OPERATIVE WORDS FOR THU AS HIGH PRES BUILDS
INTO THE RGN. TEMPS THU WL BE 25 DEGS COOLER THAN TDA. UPSLOPE
SNSH WL ALSO BE A CONCERN W/ SVRL INCHES OF ACCUM PSBL IN THE
HIGHLANDS. AM ADVSRY MAY BE REQUIRED.
HIGH PRES WL BUILD INTO THE RGN FRI AFTN AND SAT. HIGHS GNRLY IN
THE U30S E OF THE MTNS. LOWS IN THE 20S.
UPPER-LEVEL DISTURBANCES WILL BRING A CHANCE FOR SNOW SHOWERS...W/
THE BEST CHCS BEING ACROSS THE NORTHERN AND WESTERN CWA. DURG THE
XTND PD FAST UPR LVL WL PREVAIL..AND W/ THIS IS THE PTNL FOR MORE
ALBERTA CLIPPERS. A DISTURBANCE WILL PASS THROUGH SATURDAY NIGHT.
ANOTHER MAY IMPACT THE AREA TUE.
HIGHS CONT IN THE U30S/L40S SUN THRU TUE. LOWS IN THE MU20S.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
IFR STILL POSSIBLE THROUGH MID MORNING. SLY LOW LEVEL WIND SHEAR
INCREASES TODAY PEAKING TONIGHT JUST AHEAD OF A COLD FRONT. CHANCES
FOR THUNDER WITH VERY GUSTY WINDS...ON THE ORDER OF 50 KT. WINDS
SHIFT WEST AND DECREASE LATE TONIGHT.
GUSTY NW WINDS XPCTD THU. SKIES/CIGS SHOULD BE VFR. VFR CONDITIONS
ARE EXPECTED MOST OF THE TIME THU NIGHT THROUGH SUNDAY.
&&
.MARINE...
SLY GALE EXPECTED BY LATE AFTERNOON CONTINUING UNTIL THE COLD FRONT
CROSSES LATE TONIGHT.
HIGH PRES BLDG INTO THE WATERS WL LKLY CONT TO CAUSE STRONG WIND
GUSTS DURG THU. HV ISSUED A GALE WRNG FOR CHES BAY/LWR TIDAL
PTMC...AND A STRONG SCA FOR THE RMDR OF THE WATERS.
A COLD FRONT WILL PASS THROUGH THURSDAY NIGHT, GUSTY WINDS ARE
EXPECTED BEHIND THE FRONT FRIDAY. HIGH PRES OVR THE WATERS SAT.
ANOTHER COLD FRONT MAY IMPACT THE WATERS SUNDAY.
&&
.TIDES/COASTAL FLOODING...
A SOUTHERLY FLOW WILL INCREASE TODAY WITH GUSTS AROUND 35 KNOTS
DURING THE AFTERNOON AND EVENING HOURS. THE STRONG SOUTHERLY FLOW
WILL PUSH WATER UP THE MARYLAND PORTION OF THE CHESAPEAKE BAY AND
THE TIDAL POTOMAC RIVER. DESPITE THE LOW ASTRONOMICAL
NORMS...MODERATE FLOODING IS LIKELY NEAR TIMES OF HIGH TIDE
WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. A COASTAL FLOOD
HEADLINE DECISION WILL BE MADE SHORTLY.
NW WINDS WILL ALLOW FOR TIDAL ANOMALIES TO DECREASE THU.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD WATCH FROM 2 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR DCZ001.
MD...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR MDZ501.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR MDZ501-502.
COASTAL FLOOD WATCH FROM 2 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR MDZ007-011-013-014-016>018.
VA...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR
VAZ025>030-036>040-503-504.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR VAZ503-504.
COASTAL FLOOD WATCH FROM 2 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR VAZ052>055-057.
WV...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR WVZ050-
055-501>503-505-506.
FLASH FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR WVZ050-055-501>506.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 4 PM EST THIS
AFTERNOON FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR
ANZ530>532-535-536-538>540.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 PM EST THURSDAY FOR
ANZ533-534-537-541>543.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1232 AM EST WED JAN 30 2013
.SYNOPSIS...
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF FOG WILL GIVE WAY TO HEAVY RAIN TONIGHT AS LOW PRESSURE
MOVES THROUGH. SOME FLOODING IS POSSIBLE. THE RAIN WILL MOVE EAST
ON WEDNESDAY WITH COLDER AIR MOVING IN ALONG WITH SOME RAIN
CHANGING TO SNOW. TEMPERATURES WILL CONTINUE TO FALL THROUGH
FRIDAY ALONG WITH LAKE EFFECT SNOW SHOWERS.
&&
.UPDATE...
ISSUED AT 817 PM EST TUE JAN 29 2013
AT 0105Z THE KGRR 88D SHOWS RAIN AND ISOLATED THUNDERSTORMS. NO
SEVERE WX IS ANTICIPATED IN OUR AREA TONIGHT. LATEST HIGHER
RESOLUTION GUIDANCE SUCH AS THE 12Z 4KM WRF NMM INDICATES WE WILL
HAVE RAIN AND SCATTERED THUNDERSTORMS THROUGH THE OVERNIGHT
PERIOD. RAIN COULD BE HEAVY AT TIMES. THEREFORE NO HEADLINE
CHANGES ARE PLANNED/NECESSARY THIS EVENING AND THE FLOOD WATCH CONTINUES
IN EFFECT THROUGH WEDNESDAY AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF PATCHY DENSE FOG WILL CONTINUE THIS EVENING ACROSS THE
NORTHERN ZONES UNTIL THE WARM FRONT LIFTS THROUGH. COVERAGE IS
VARIABLE ENOUGH TO NOT GO WITH A DENSE FOG ADVISORY BUT WILL HAVE
TO MONITOR OBS NEXT FEW HOURS.
FLOOD WATCH CONTINUES TONIGHT FOR ALL ZONES. MOST IF NOT ALL OF
THE SNOW IS GONE ACROSS THE CENTRAL AND SOUTHERN ZONES BUT SOME
SNOWMELT CONTRIBUTION REMAINS UP NORTH WHERE QPF IS EXPECTED TO BE
1 TO 2 INCHES. 12Z MODEL GUIDANCE SHIFTED NORTH WITH THE AXIS OF
HEAVIEST QPF ALTHOUGH THE HRRR HAS BEEN SHOWING THE MOST
CONVECTIVE...AND HEAVIER...RAINS FURTHER SOUTH AND EAST. SEE HYDRO
SECTION OF FORECAST FOR SPECIFICS ON RIVER FLOOD WARNINGS.
EXPECT THE HEAVIEST RAINS TO MOVE INTO WESTERN ZONES THIS EVENING
THEN MARCH STEADILY ACROSS THE FORECAST AREA OVERNIGHT...DEPARTING
THE EASTERN ZONES WEDNESDAY MORNING. THE DEFORMATION RAIN/SNOW
ZONE SHOULD BE REACHING THE NORTHWEST FORECAST AREA WEDNESDAY
MORNING. WILL HAVE TO WATCH THIS AREA FOR ACCUMULATING SNOW BY LATE
WEDNESDAY MORNING INTO THE AFTERNOON. COLD AIR ARRIVES IN THE
AFTERNOON WITH LAKE EFFECT KICKING IN WEDNESDAY NIGHT. EXPECT LAKE
EFFECT TO PENETRATE INLAND THURSDAY AND THURSDAY NIGHT WITH FLOW
GOING NORTHWEST TO WEST.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 348 PM EST TUE JAN 29 2013
THE ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT THROUGH THE WEEKEND.
BOTH MODELS SHOW THE DEEP UPPER TROUGH MOVING EAST AWAY FROM THE
AREA AND TAKING THE CORE OF THE COLD AIR WITH IT. THE DGZ IS ALREADY
GOING TO BE VERY LOW FRIDAY AND WITH THE COLD AIR MOVING AWAY WE/LL
SEE THE EASTERN EDGE OF THE LAKE EFFECT SNOW SHOWERS RETREATING
TOWARD THE LAKE SHORE AND THEN DIMINISHING FRIDAY NIGHT AND
SATURDAY.
THE NEXT CHC FOR SNOW AFTER THAT WILL BE MONDAY WHEN A CLIPPER
MOVES TOWARD NRN LWR. THE GFS TAKES A MORE SRN TRACK AND WOULD
GIVE US MORE SNOW. HOWEVER...WE HAVE NOT HAD MANY CLIPPERS THAT
HAVE CROSSED THE CWA THIS YEAR AND SO WE/LL LEAN MORE TOWARD THE
FARTHER NORTH ECMWF. TEMPS WILL WARM FROM HIGHS IN THE MID TEENS
FRIDAY TO MID 30S BY MONDAY BEFORE COOLING OFF TUESDAY AFTER THE
CLIPPER DRAGS A COLD FRONT THROUGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1228 AM EST WED JAN 30 2013
VERY COMPLEX AVIATION FORECAST THE NEXT 24 HOURS...AS A LOW
PRESSURE CENTER MOVES THROUGH THE AREA. CHANGEABLE AVIATION
CATEGORIES AND WIND DIRECTION WILL MAKE FOR A COMPLICATED
FORECAST. IN GENERAL...AVIATION CONDITIONS WILL DIP OVERNIGHT BACK
INTO IFR AT MOST SITES AS THE WINDS SLACK OFF A BIT WITH THE LOW
AND HEAVIER RAIN MOVES BACK IN. A GRADUAL IMPROVEMENT SHOULD BE
SEEN ON WEDNESDAY...BUT WE SHOULD NOT IMPROVE BEYOND MVFR THROUGH
THE DAY. RAIN WILL BEGIN TO CHANGE TO SNOW FROM WEST TO EAST
DURING THE EVENING HOURS.
&&
.MARINE...
ISSUED AT 348 PM EST TUE JAN 29 2013
WILL HOIST A SMALL CRAFT ADVISORY FOR TONIGHT THROUGH THURSDAY
MORNING. THIS MAY HAVE TO BE UPGRADED TO A GALE WARNING FOR
WEDNESDAY LATER ON...BUT FOR NOW IT APPEARED MARGINAL ENOUGH TO
JUST GO WITH A SCA THROUGH THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 957 PM EST TUE JAN 29 2013
HAVE ISSUED A FLOOD WARNING FOR THE LAKESHORE COUNTIES AS WELL AS
LAKE AND NEWAYGO COUNTY. AREAS THAT RECEIVED SUBSTANTIAL LAKE
EFFECT SNOW IN THE LAST WEEK OR SO HAVE SEEN A RAPID SNOW MELT
THAT HAS OCCURRED OVER FROZEN GROUND. THEREFORE...SNOW MELT WATER
AND RAINFALL IS GOING INTO RUNOFF AS OPPOSED TO INFILTRATING INTO
THE GROUND. RAINFALL TOTALS HAVE BEEN IMPRESSIVE SINCE LAST
NIGHT...WITH MUSKEGON SEEING OVER 2.25 INCHES OF RAIN NOW. THE
COMBINATION SNOW MELT WATER...RAINFALL OF THE LAST 24 HOURS AND
ADDITIONAL RAINFALL COMING UP TONIGHT HAS PROMPTED THE AREAL FLOOD
WARNING. DROPPED THE FLOOD WATCH IN THESE COUNTIES GIVEN THE
WARNING. THE FLOOD WATCH CONTINUES FOR THE REMAINDER OF THE AREA.
THE EXPECTATIONS IN THE WARNING AREA ARE THAT WE WILL SEE SMALLER
STREAMS AND RIVERS SPILL OUR OF THERE BANKS...PONDING OF WATER IN
LOW SPOTS OF ROADWAYS AND FLOODING OF CULVERTS...DITCHES AND FIELDS.
A SATELLITE PRECIPITATION ESTIMATE (SPENES) WAS RECENTLY ISSUED
ADVISING OF THE POTENTIAL OF ANOTHER 1-2 INCHES OF RAINFALL ACROSS
OUR AREA THROUGH 400 AM. WE WILL BE MONITORING THE COUNTIES TO THE
EAST OF THE WARNING AREA...BUT CONCERNS ARE NOT AS HIGH THERE AS
THE SNOW PACK WAS MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH THROUGH THIS AFTERNOON FOR MIZ039-040-045-046-051-
052-057>059-065>067-072>074.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...LAURENS
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...DUKE
HYDROLOGY...DUKE
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1205 AM EST WED JAN 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 504 PM EST TUE JAN 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS INTO NEW MEXICO. WEAK SHRTWVS
EMBEDDED IN THE SW FLOW FROM THE SRN PLAINS INTO THE GREAT LAKES
SUPPORTED AREAS OF SHRA/TSRA NEAR A SFC FRONT EXTENDING FROM NE WI
THROUGH CNTRL MO AND INTO CNTRL OK. THE MAIN SHRTWV WAS REMAINED
NEAR THE BASE OF THE TROUGH...MOVING TOWARD THE TX/OK PANHANDLE.
PCPN HAD DIMINISHED OVER UPPER MICHIGAN WITH MAINLY SOME SCT LIGHT
SHOWERS MOVING THROUGH FAR SRN UPPER MI. WEST WINDS AND SLIGHTLY
DRIER AIR BEHIND A TROUGH SLIDING TO NEAR P53-ISQ HAS BROUGHT
IMPROVED VISIBILITIES THROUGH THE CNTRL AND WEST CWA.
ALTHOUGH THE 12Z ECMWF WAS A BIT SLOWER THAN THE 12Z GFS...THE MODELS
WERE IN RELATIVELY GOOD AGREEMENT WITH REGARD TO OVERALL PCPN/SNOW
POTENTIAL ACROSS THE CWA. ALTHOUGH THE 12Z NAM HAD SHIFTED THE
HEAVIER QPF AXIS WELL TO THE EAST...THE 18Z RUN HAS COME BACK INTO
BETTER AGREEMENT WITH THE GLOBAL MODELS. MODELS DIFFICULTY IN
HANDLING THE CONVECTION AND HEAVY RAIN NEAR THE FRONT MAY ACCOUNT
FOR A PORTION OF THE INCONSISTENCY AND VARIABILITY AND STILL LEADS
GREATER THAN USUAL UNCERTAINTY. ALTHOUGH THERE IS MODERATE
CONFIDENCE WITH THE MULTI-MODEL BLEND OF THE GFS/ECMWF/NAM/REG-GEM
USED FOR QPF...TIMING OF THE HEAVIER PCPN ONSET MAY BE A BIT DELAYED
GIVEN ECMWF/NAM TRENDS.
THE STRONGEST DYNAMICS ARE EXPECTED TO DEVELOP BTWN 12Z-18Z/WED AS
THE NM SHRTWV LIFTS TOWARD THE GREAT LAKES. A COUPLED UPPER LEVEL
JET STRUCTURE AND RESULTING STRONG 800-600 MB FGEN WILL SUPPORT A
PERIOD OF MODERATE TO HEAVY PCPN IN THE REGION...WITH THE BEST
CHANCE FOR HEAVY SNOW OVER THE SE HALF OF UPPER MI. EXPECT A SHARP
NW EDGE OF THE PCPN BAND DUE TO STRONG DESCENDING FGEN CIRCULATION
BRANCH WHICH REDUCES CONFIDENCE IN PCPN AMOUNTS THROUGH CNTRL UPPER
MI. QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE WITH SNOW/WATER RATIO
VALUES NEAR 16/1 SUPPORTS GENERALLY 4 TO 8 INCH SYNOPTIC
SNOW...GREATEST OVER THE FAR S AND EAST. LAKE ENHANCED SNOW WILL
GENERALLY BE LIGHT EARLY WED WITH LOW INVERSION HEIGHTS NEAR 4K FT
AND 850 MB TEMPS ONLY NEAR -10C BUT BY WED AFTERNOON SNOWFALL RATES
OVER N CNTRL AND FAR WEST NEAR IWD SHOULD INCREASE AS 850 MB TEMPS
FALL TO NEAR -16C. ALTHOUGH UPSLOPE FLOW SHOULD ENHANCE SNOWFALL
RATES...CYCLONIC 350 FLOW MAY ALSO LEAD TO GREATER AMOUNTS NEAR THE
SHORE WED AFTERNOON.
FCST CONFIDENCE WAS HIGH ENOUGH TO UPGRADE WATCHES TO WARNINGS OVER
THE EAST HALF BUT WITH AMOUNTS ONLY IN THE 2 TO 5 INCH RANGE OVER
MARQUETTE AND DICKINSON COUNTIES THROUGH WED AND PROXIMITY TO THE
EDGE OF THE SYNOPTIC PCPN...AN ADVY WAS ISSUED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 29 2013
INITIAL PART OF THE LONG TERM FORECAST IS HIGHLY DEPENDENT ON THE
TRACK OF THE SHORTWAVE RIDING UP THE UPPER TROUGH OVER THE CENTRAL
CONUS AND THE ASSOCIATED LOW DEVELOPING IN NORTHERN LOWER MI AND
THEN SHIFTING NORTHEAST INTO QUEBEC ON WEDNESDAY NIGHT. THE SHORT
TERM DISCUSSION COVERS MUCH OF THE DETAILS WITH THIS SYSTEM AND THE
MAIN FEATURE TO CAPTURE IN THE LONG TERM WITH THIS SYSTEM IS THE
DIMINISHING TREND IN THE POPS/QPF OVER THE EASTERN CWA.
BEHIND THIS FEATURE...EXPECT COLD AIR TO SURGE SOUTHEAST OVER THE
UPPER GREAT LAKES REGION AND REMAIN INTO THE WEEKEND. THIS COLD
AIR...H850 TEMPS IN THE LOW -20S CELSIUS...MOVING ACROSS THE
RELATIVELY WARM LAKE SUPERIOR WATERS WILL LEAD TO PERSISTENT LAKE
EFFECT. AMOUNTS AND LOCATIONS WILL LARGELY DEPEND ON WIND DIRECTION
AND DEEPER MOISTURE DURING THIS PERIOD.
FOR WEDNESDAY NIGHT...LAKE EFFECT WILL BE INCREASING IN INTENSITY
OVER THE WEST THROUGH THE NIGHT DUE TO INCREASING COLD AIR AND
DEEPER MOISTURE ARRIVING FROM THE NORTHWEST. THIS WILL PUSH
INVERSION HEIGHTS TOWARDS 10KFT OVER THE WITH WESTERN AREAS AND
WITH DELTA-T VALUES AROUND 23...LAKE INDUCED CAPE VALUES RISE
TOWARDS 500-700 J/KG. EXPECT THE HIGHEST AMOUNTS...2-6 INCHES...IN
THE NORTH-NORTHWEST WIND FAVORED LOCATIONS. OVER THE
EAST...FORECAST IS A LITTLE MORE UNCERTAIN DUE TO THE SYSTEM...BUT
THEY TOO SHOULD TRANSITION TO LAKE EFFECT. WITH MOISTURE HELP FROM
THE SYSTEM...SNOW AMOUNTS WILL BE HIGHER THERE ESPECIALLY IN THE
LOCATIONS FAVORED BY NORTH-NORTHWEST WINDS. THE HIGHEST AMOUNTS WILL
LIKELY OCCUR THROUGH THE NIGHT OVER THE WESTERN PORTIONS OF ALGER
COUNTY...WHERE COASTAL EFFECTS FROM NORTHERN MARQUETTE COUNTY WILL
LIKELY INCREASE CONVERGENCE THERE AND THUS SNOWFALL AMOUNTS. HAVE
TRENDED POPS TOWARDS THIS IDEA FOR THE WEDNESDAY NIGHT PERIOD.
WITH THE COLD AIR CONTINING TO FLOW OVER THE AREA ON
THURSDAY...MULTI-BAND LAKE EFFECT WILL BE AIDED BY THE INCREASED MID
LEVEL MOISTURE MOVING OVER THE AREA BEHIND A SHORTWAVE DROPPING
THROUGH THE UPPER/MID MISSISSIPPI VALLEY ON THURSDAY. THIS WILL LEAD
TO INVERSION HEIGHTS IN THE 7-10KFT RANGE OVER THE AREA...WITH THE
HIGHEST VALUES OVER THE EAST. THE MAIN DETERMINING FACTOR FOR SNOW
AMOUNTS IN THE NORTHWEST WIND FAVORED LOCATIONS ON THURSDAY WILL BE
WHEN THE DGZ FALLS BELOW OR TO THE BOTTOM OF THE CLOUD LAYER. THIS
WILL OCCUR FIRST OVER THE WEST AND THEN OVER THE EAST LATE IN THE
DAY. THIS WILL LEAD TO A TRANSITION TO LOWER SNOW RATIOS WITH THE
TRANSITION TO MORE COLUMNS THAT IS USUALLY SEEN IN COLD/ARCTIC AIR
MASSES. WITH THE WINDS BACKING TO MORE OF A NORTHWEST WIND
DIRECTION THROUGH DAY...WOULD EXPECT THERE TO BE A COUPLE ENHANCED
LOCATIONS DUE TO INCREASED CONVERGENCE. AT THIS TIME...WOULD EXPECT
IT TO BE OVER GOGEBIC/ONTONAGON AND ALGER COUNTIES.
HIGH PRESSURE SLIDING SOUTHEAST FROM THE DAKOTAS ON THURSDAY NIGHT
WILL LEAD TO BACKING WINDS TO THE WEST OVER THE WESTERN LAKE AND
WEST-NORTHWEST OVER THE EAST. THIS WILL CONTINUE INTO FRIDAY AS THE
HIGH MOVES INTO THE MID MISSISSIPPI VALLEY AND LEADS TO WEST TO
WEST-SOUTHWEST WINDS. THESE WINDS WILL BE AIDED BY A WEAK LOW
DEVELOPING OVER EASTERN LAKE SUPERIOR. COLD AIR IS STILL IN THE
LOWER -20S CELSIUS DURING THE PERIOD...SO THE LAKE EFFECT WILL BE
ONGOING. BUT...WITH THE HIGH REDUCING THE MOISTURE ABOVE H850 AND
INCREASING THE SUBSIDENCE INVERSION EXPECT THERE TO BE A GRADUAL
DECREASE IN INTENSITY DURING THAT TIME FRAME.
DEFINITELY THINK THAT THE NORTH-NORTHWEST WIND LOCATIONS WILL NEED
LAKE EFFECT SNOW ADVISORIES DURING THIS WEDNESDAY NIGHT INTO
THURSDAY NIGHT PERIOD. WARNINGS ARE A LITTLE MORE UNCERTAIN DUE TO
THE LIMITED PERIODS OF THE BEST OMEGA WITHIN THE DGZ. OUT OF ALL OF
THE LOCATIONS...WOULD THINK THAT ALGER COUNTY WOULD HAVE THE BEST
OPPORTUNITY OF SEEING WARNING SNOWFALL AMOUNTS. OPTED TO GO AHEAD
AND ISSUE THE LAKE EFFECT SNOW ADVISORY FOR GOGEBIC/ONTONAGON
COUNTIES AND THE REST OF THE FAVORED AREAS WILL NEEDED TO BE ADDED
IN THE NEXT 12-24HRS.
HEADING INTO THE WEEKEND...THE COLDER AIR WILL BEGIN TO LOSE IT/S
GRIP ON THE AREA AS THE UPPER TROUGH SHIFTS TO THE EAST AND AREA
COMES UNDER NORTHWEST FLOW ALOFT. THESE PERIODS COME DOWN TO
TIMING/LOCATING SHORTWAVES MOVING THROUGH THE FLOW AND HAVE TRIED
TO FOLLOW A GENERAL CONSENSUS FOR TIMING THESE WAVES. FIRST ONE
LOOKS TO MOVE THROUGH THE AREA ON SATURDAY NIGHT AND AGAIN ON
SUNDAY NIGHT INTO MONDAY. BETWEEN THOSE TWO PERIODS...THERE SHOULD
BE ENOUGH COLD AIR TO SUPPORT LAKE EFFECT SNOW IN AREAS FAVORED BY
NORTHWEST WINDS.
WITH THE COLD AIR SPILLING INTO THE AREA...A COOLING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WORK WEEK. FRIDAY CONTINUES TO
LOOK LIKE THE COLDEST DAY OVER THE NEXT 7 DAYS...WITH HIGHS OVER THE
WEST STRUGGLING TO RISE ABOVE 0 DEGREES. THIS COLD AIR WILL CAUSE
WIND CHILL VALUES TO APPROACH -25 ON ON THURSDAY NIGHT INTO
FRIDAY MORNING AND AGAIN FRIDAY NIGHT INTO SATURDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. TEMPERATURES WILL THEN WARM
BACK TO MORE NORMAL VALUES BY THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1205 AM EST WED JAN 30 2013
CONFIDENCE IN THIS FORECAST CONTINUES TO BE LOW AS DRIER AIR SEEMS
TO BE WINNING OVER UPSLOPE LOW CIGS THAT WERE EXPECTED TO REMAIN AND
DEVELOP OVERNIGHT. MVFR CONDITIONS WILL CONTINUE AT CMX THROUGH THE
PERIOD. AT IWD...LAKE ENHANCEMENT KICKS IN WITH VISIBILITY FALLING
TO IFR BY WED MORNING AND STAYING THERE THROUGH THE REST OF THE
PERIOD WITH UPSLOPE HELPING THE LAKE EFFECT. MVFR CONDITIONS AT SAW
WILL GIVE WAY TO IFR BY WED MORNING AS SYSTEM SNOW MOVES IN. AS
WINDS GO NNW BY EVENING...CONDITIONS SHOULD IMPROVE TO MVFR AT SAW
AS SYSTEM SNOW MOVES OUT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 PM EST TUE JAN 29 2013
A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH LAKE HURON WEDNESDAY
AND TO THE NORTHEAST BY WEDNESDAY NIGHT WILL LIKELY BRING A PERIOD
OF N TO NW GALES TO CENTRAL AND EASTERN LAKE SUPERIOR LATE TONIGHT
INTO WEDNESDAY NIGHT. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING
OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT
TIMES LATE WEDNESDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 PM CST WEDNESDAY FOR
MIZ011.
WINTER STORM WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
MIZ012>014.
WINTER STORM WARNING FROM 4 AM EARLY THIS MORNING TO 7 AM EST
THURSDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM EST /6 AM CST/ THIS MORNING
TO 7 AM EST /6 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST
THURSDAY FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
FRIDAY FOR LSZ265>267.
GALE WARNING FROM 10 AM THIS MORNING TO 4 AM EST THURSDAY FOR
LSZ267.
GALE WARNING FROM 5 AM EARLY THIS MORNING TO 4 AM EST THURSDAY
FOR LSZ264>266.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263-264.
GALE WARNING FROM 5 AM EARLY THIS MORNING TO 10 PM EST THIS
EVENING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1024 AM MST WED JAN 30 2013
.SHORT TERM...VALID FOR TDY AND THU...
SEVERAL UPDATES TO THE FORECAST THIS MORNING WITH THIS VERY ACTIVE
AND DIFFICULT WEATHER PATTERN.
FIRST UPDATE THIS MORNING HAS BEEN TO INCREASE WINDS FOR SHERIDAN
COUNTY WYOMING TO ASHLAND AND BROADUS FOR THIS AFTERNOON AND
EVENING. THE NAM AND RAP ARE CATCHING ON TO A STRONGER SURFACE LOW
OVER WYOMING THIS MORNING THAN MODELS HAD PREVIOUSLY ADVERTISED.
AS THIS SURFACE LOW SHIFTS SOUTH AND EAST THIS MORNING AHEAD OF
THE NEXT COLD FRONT...EXPECT WINDS WILL INCREASE OUT OF THE
NORTHWEST ACROSS THE AREAS...WITH GUSTS 30 TO 40 MPH
COMMON...ESPECIALLY IN HIGHER TERRAIN LOCATIONS INCLUDING ABERDEEN
HILL ALONG I90. GIVEN THE RECENT SNOW COVER IN THESE LOCATIONS AND
SNOW EXPECTED THROUGH THIS EVENING IN THESE LOCATIONS...BLOWING
SNOW WILL BECOME A TRAVEL HAZARD ALONG SECTIONS OF I90 AND US 212.
HAVE ALSO ADDED THIS BLOWING SNOW WORDING TO THE WINTER WEATHER
ADVISORY ALREADY IN PLACE FOR THESE LOCATIONS. THE STRONGEST WINDS
WILL SHIFT EAST THIS EVENING AS THE COLD FRONT ROLLS THROUGH THOSE
LOCATIONS...WITH THE BLOWING DIMINISHING BY THURSDAY MORNING.
MOIST WESTERLY FLOW INTO THE PARADISE VALLEY THIS MORNING WILL
CONTINUE THROUGH TONIGHT AND INTO THURSDAY MORNING. MODELS ARE
BECOMING MORE CONFIDENT IN A PROLONGED UPSLOPE SNOW EVENT INTO THE
ABSAROKA MOUNTAINS ON THE EAST SIDE OF THE VALLEY. THUS HAVE
ISSUED A WINTER WEATHER ADVISORY FOR 3 TO 6 INCHES OF SNOW AND
BLOWING SNOW. THE HIGHEST SNOW AMOUNTS WILL BE LOCATED ALONG AND
EAST OF HIGHWAY 89.
LASTLY...EXPANDED POPS THIS MORNING TO ACCOUNT FOR MORE WIDESPREAD
SNOWFALL THAT PREVIOUSLY ANTICIPATED. LATEST MODEL RUNS CONTINUE
TO INDICATE THE BEST TIME FOR SNOWFALL TO BACK INTO THE BILLINGS
AREA WILL BE THIS EVENING AND OVERNIGHT. HOWEVER...WILL HAVE TO
CONTINUE TO WATCH HOW QUICKLY THIS SNOW BACKS IN TO THE WEST...AS
THE LATEST GFS IS MORE AGGRESSIVE AND WOULD RESULT IN HIGHER
SNOWFALL AMOUNTS...WITH SNOW BEGINNING THIS AFTERNOON.
CHURCH
&&
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
FRIDAY WILL SEE THE DEPARTURE OF THE ARCTIC INTO THE DAKOTAS BUT
NOT BEFORE A SHORTWAVE IN NORTHWEST FLOW ALOFT FORCES SOME SHOWER
ACTIVITY. DEFINITELY WILL SEE WARMING TEMPERATURES ACROSS THE EAST
AND WITH MOST OF THE PRECIP FALLING INTO DOWNSLOPING WINDS DO NOT
EXPECT MUCH IN THE WAY OF AMOUNTS. SHOULD SEE 15 TO 20 DEGREE
TEMPERATURE INCREASES ACROSS THE CENTRAL AND EASTERN ZONES WITH
THE WEST BEING WINDY AND MIXED WITH TEMPERATURES IN THE 40S.
UPPER LEVEL RIDGE WEST OVER THE PACIFIC NORTHWEST ON SATURDAY
BEGINS TO SHIFT EAST AND FLATTEN THROUGH SUNDAY. THIS SUPPORTS
CONTINUALLY FALLING SURFACE PRESSURES EAST OF THE CONTINENTAL
DIVIDE AND TIGHTENS WIND GRADIENTS FOR GAP FLOW AREAS. THIS WILL
BRING DRY AND WARMER CONDITIONS BUT AM STAYING A BIT BELOW
GUIDANCE AS DRAINAGE FLOWS AND EXISTING SNOW COVER COULD LIMIT
FULL WARMING.
MONDAY A TROUGH BEGINS BUILDING ALONG THE WEST COAST AND HEIGHTS
BUILD AGAIN ACROSS THE REGION. STRONG FLOW ALOFT OVER THE CANADIAN
ROCKIES KEEPS LEESIDE TROUGHING IN PLACE SO EXPECT WIND TO BE
UNYIELDING FOR LIVINGSTON AND NYE FOR MOST OF THE EXTENDED. THIS
PATTERN PERSISTS WITH FLUCUATIONS IN THE SURFACE TROUGH STRENGTH
THROUGH TUESDAY. MODELS TRY TO DEVELOP A CUTOFF LOW ALONG THE WEST
COAST LATER IN THE EXTENDED BUT INITIALLY THIS JUST KEEPS THE
RIDGE IN PLACE WITH DRY AND MILD WEATHER WEDNESDAY. BORSUM
&&
.AVIATION...
ARCTIC BOUNDARY BISECTING CENTRAL PORTION OF THE FORECAST AREA
WILL BE THE FOCUS FOR SNOW AND IFR CONDITIONS TODAY AND TONIGHT.
AREAS FROM ROUNDUP TO BILLINGS TO SHERIDAN WILL BE IN THE VICINITY
OF THE BOUNDARY AND WILL SEE PERIODS OF SNOW THROUGH THE NEXT 24
HOURS.
IN THE KSHR VICINITY EXPECT GUSTY NORTHWEST WINDS TO
DEVELOP MID DAY THROUGH EARLY THIS EVENING...WITH GUSTS TO AROUND
35 KTS AT TIMES. THIS WILL PRODUCE SIGNIFICANT BLOWING AND
DRIFTING SNOW ACROSS SOUTHERN BIG HORN AND MUCH OF SHERIDAN COUNTY
RESULTING IN LOCAL LIFR CONDITIONS THROUGH 03Z.
AREAS EAST OF MILES CITY TO BROADUS WILL SEE MAINLY SCATTERED
SNOW SHOWERS TODAY AND TONIGHT WITH OCCASIONAL MVFR CONDITIONS. TO
THE WEST AROUND KLVM GUSTY WEST TO NORTHWEST WINDS WILL KEEP VFR
CONDITIONS IN PLACE...BUT EXPECT GUSTS TO AROUND 35 KTS AT TIMES.
CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 030 006/027 022/042 023/042 028/046 028/046 026/048
7/S 75/S 22/J 00/B 01/N 11/N 11/B
LVM 035 020/039 030/041 025/042 030/043 029/046 030/048
7/S 64/S 22/W 11/N 11/N 11/N 11/N
HDN 024 005/022 018/041 017/040 020/043 025/043 023/045
8/S 87/S 22/J 00/U 01/U 11/U 11/U
MLS 011 911/009 008/035 016/037 019/040 023/039 023/041
8/S 64/S 22/J 10/B 01/U 01/B 11/U
4BQ 015 905/013 009/037 016/039 020/041 024/041 021/043
8/S 97/S 22/J 00/U 00/U 01/B 00/U
BHK 007 918/002 902/033 017/034 019/037 020/037 021/039
6/S 41/B 12/J 10/B 00/U 01/B 11/B
SHR 025 005/026 017/039 016/041 017/043 023/044 025/046
9/S 97/S 22/W 00/U 00/U 01/U 01/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND CHILL ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO NOON
MST THURSDAY FOR ZONES 32-33-37.
WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST THURSDAY FOR
ZONES 36-38-57-58-64.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONE 63.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST THURSDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
943 PM CST THU JAN 31 2013
.UPDATE...RADAR DATA FROM KUEX...KLNX AND KGLD INDICATE A WEAK
BAND OF PRECIPITATION OVER SOUTHWESTERN NEBRASKA AND NORTHWESTERN
KANSAS...WITH SOME OF THIS ACTIVITY NOW CREEPING INTO EXTREME
SOUTHWESTERN PORTIONS OF OUR CWA. EVENING UPPER AIR ANALYSIS
INDICATES A ~90KT MID LEVEL JET STREAK OVER THE CENTRAL PLAINS
NOW...WITH THE RIGHT-REAR QUADRANT OF THIS JET STREAK MOVING INTO
SOUTHWESTERN NEBRASKA AND NORTHWESTERN KANSAS. THERE APPEARS TO BE
JUST ENOUGH OF A DIRECT THERMAL CIRCULATION AND RESULTANT MID
LEVEL FRONTOGENESIS FOR VERY LIGHT PRECIPITATION PRODUCTION. IT
DOES NOT APPEAR AS THOUGH MUCH OF THIS PRECIPITATION IS MAKING IT
TO THE GROUND HOWEVER AS FORECAST PROXIMITY SOUNDINGS FROM ACROSS
OUR SOUTHWEST...PER THE NAM AND RAP...SUGGEST LOWER TROPOSPHERIC
MOISTURE IS FAIRLY MEAGER. BUT THERE WAS A REPORT OF BRIEF
PRECIPITATION EARLIER THIS EVENING ACROSS EXTREME SOUTHWESTERN
NEBRASKA FROM THIS SAME BAND. THE HRRR SEEMS TO HAVE A GOOD HANDLE
ON THIS SITUATION BY SUGGESTING THIS BAND WILL MEANDER OVER
SOUTHWESTERN PORTIONS OF OUR CWA TONIGHT WHICH MAY PRESENT
PERIODIC SNOW FLURRIES TO THOSE AREAS. AS A RESULT...WENT AHEAD
AND INTRODUCED FLURRIES TO THE FORECAST FOR TONIGHT ACROSS OUR
SOUTHWEST. THE REMAINDER OF THE FORECAST REMAINS IN GREAT
SHAPE...WITH ONLY A FEW MINOR CHANGES MADE TO HOURLY
TEMPERATURE...WIND...DEWPOINT AND SKY GRIDS TO BETTER REFLECT
CURRENT OBSERVATIONS.
&&
.PREV DISCUSSION... /ISSUED 549 PM CST THU JAN 31 2013/
AVIATION...00Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. CEILINGS GENERALLY BETWEEN 5000 AND 8000FT AGL ARE
FORECAST THROUGH MUCH OF THE TAF PERIOD. ONE SET OF GUIDANCE DOES
SUGGEST MVFR CEILINGS WILL BRIEFLY OCCUR AT THE TERMINAL AROUND
12Z FRIDAY...BUT CONFIDENCE IN SUCH CEILINGS BEING REALIZED IS FAR
TOO LOW TO MENTION IN THE TAF AT THIS TIME. A LIGHT AND VARIABLE
LOW LEVEL WIND FIELD IS EXPECTED TONIGHT...BECOMING MORE
ESTABLISHED FROM THE SOUTHWEST...SUSTAINED AROUND 14KTS WITH GUSTS
NEAR 20KTS...DURING THE DAY FRIDAY. THERE ARE SOME INDICATIONS OF
WEAK LOW LEVEL WIND SHEAR DEVELOPING AT THE TERMINAL DURING THE
08-13Z TIME FRAME AS A 30-35KT JET STREAK DEVELOPS JUST ABOVE THE
BOUNDARY LAYER NEAR 2000FT AGL. AT THIS TIME HOWEVER CONFIDENCE IS
NOT HIGH ENOUGH THAT THE LOW LEVEL WIND SHEAR WILL BE STRONG
ENOUGH TO WARRANT A MENTION IN THE TAF...BUT NONETHELESS THIS WILL
NEED TO BE MONITORED THROUGH THE NEXT 12 OR SO HOURS. VISIBILITY
RESTRICTION IS NOT EXPECTED AT THE TERMINAL THROUGH THE NEXT 24
HOURS.
PREV DISCUSSION... /ISSUED 407 PM CST THU JAN 31 2013/
SHORT TERM...TONIGHT AND FRIDAY.
WE REMAIN IN NORTHWEST FLOW ALOFT FOR THE SHORT TERM. THE SURFACE
HIGH...CENTERED OVER THE NORTHERN PLAINS WILL SHIFT EAST...PLACING
US WITHIN RETURN FLOW BY THE OVERNIGHT.
TEMPERATURES SHOULD DROP SHARPLY TONIGHT AS WIND DROPS OFF...BUT
STEADY OUT FOR THE OVERNIGHT AS WIND SHIFTS TO THE SOUTH AND
INCREASES A BIT TOWARD DAWN. LOWS WILL LARGELY BE IN THE SINGLE
DIGITS...BUT COULD HAVE BEEN COLDER IF NOT FOR THE RETURN FLOW.
LOOKS LIKE WE ARE JUST FAR ENOUGH SOUTHWEST TO PRECLUDE ANY WIND
CHILL ISSUES...AS WAS THE CASE EARLY THIS MORNING.
MAINLY A TEMPERATURE FORECAST FOR FRIDAY AS SOUTHWEST FLOW FOLLOWS
THE FETCH OF THE SNOW FIELD...WHICH SHOULD HAMPER HIGH TEMPERATURE
WHERE THERE IS SNOW...SO I ESSENTIALLY LOWERED HIGHS OVER THE SNOW
PACK...AND RAISED TEMPERATURES A BIT IN THE NORTHWESTERN
CWA...INCLUDING ORD. SKY COVER WILL INCREASE ESPECIALLY TOWARD
AFTERNOON AS ANOTHER SHORTWAVE TROUGH APPROACHES WITHING NORTHWEST
FLOW. WE WILL BE NEAR THE ENTRANCE REGION OF AN UPPER LEVEL JET
STREAK...WHICH COULD INDUCE SOME FLURRIES IN OUR NORTHERN CWA BY
LATE AFTERNOON..ESPECIALLY NEAR AN UNUSUALLY ORIENTED WARM FRONT
APPROACHING FROM THE WEST. MOST MODELS DO NOT INDICATE ANY SNOW
FLURRY ACTIVITY...BUT THE NMM AND TO SOME EXTENT..THE GFS SHOW THIS
TO BE A POSSIBILITY...SO INCLUDING THIS FOR THE VERY LATE AFTERNOON.
WIND WILL INCREASE FROM THE SOUTH AHEAD OF THE WARM FRONT MOVING IN
FROM THE WEST BY AFTERNOON...BUT AGAIN...THE FETCH OF THE WIND AND
INCREASING CLOUDINESS WILL ROB US ONCE AGAIN OF A POTENTIALLY MORE
MILD DAY FOR THE MAJORITY OF OUR CWA.
LONG TERM...FRIDAY EVENING THROUGH NEXT THURSDAY. FIRST OFF...VERY
FEW NOTICEABLE CHANGES WERE MADE FROM THE PREVIOUS FORECAST...AS THE
MAIN THEME CONTINUES TO BE PRECIPITATION-FREE CONDITIONS WITH THE
POSSIBLE EXCEPTION OF FRIDAY EVENING MAINLY IN THE NORTHEAST...AND
A SEVERAL-DAY STRETCH OF DECENT TEMPERATURES AVERAGING AROUND 10
DEGREES ABOVE NORMAL.
STARTING OFF FRIDAY NIGHT...MAIN CHANGE FROM PREVIOUS FORECAST IS
THE INTRODUCTION OF A CHANCE/SLIGHT CHANCE OF FLURRIES DURING THE
EVENING HOURS MAINLY ACROSS OUR NORTHEAST 1/2...OR ROUGHLY
NORTHEAST OF A LOUP CITY-SUPERIOR LINE. THERE IS GOOD AGREEMENT
AMONGST VARIOUS 12Z MODELS SUCH AS THE NAM/GFS/ECMWF THAT A LOW
AMPLITUDE SHORTWAVE TROUGH WILL PASS EAST-SOUTHEAST OVER THE AREA
THROUGH THE NIGHT...FOCUSED WITHIN THE ENTRANCE REGION OF A 100+KT
JET AT 300MB. ALTHOUGH FORCING IS NOT GREAT WITH THIS WAVE...THERE
APPEARS TO BE INCREASING CHANCES OF AT LEAST LIGHT MEASURABLE SNOW
ALONG AN AXIS FROM NORTHEAST NEB INTO IA. AT THIS POINT...AM
THINKING THAT THESE MEASURABLE CHANCES SHOULD REMAIN JUST
NORTHEAST OF OUR CWA...BUT IT COULD BE A VERY CLOSE CALL
ESPECIALLY PER THE FORECAST REFLECTIVITY OF THE 12Z 4K WRF-NMM...AND
SOMETHING FOR NEXT FEW SHIFTS TO WATCH. IN THE MEANTIME...AT LEAST
WANTED TO GET THE NON-MEASURABLE FLURRY WORDING GOING...AS NAM
FORECAST SOUNDINGS SUGGEST A FAIRLY DEEP SATURATED LAYER ABOVE
850MB. FOR NOW WILL RUN WITH THE THINKING THAT ANY FLURRY
POTENTIAL WILL END ACROSS OUR CWA BY MIDNIGHT AS FORCING PASSES
MORE TO THE EAST. AT THE SURFACE...THE PASSING UPPER WAVE WILL
DRAG A SURFACE TROUGH ACROSS THE CWA THROUGH THE NIGHT...TURNING
BREEZES FROM THE WEST-NORTHWEST AT AROUND 10-15 MPH AS IT PASSES.
OFTEN...TEMPS TEND TO JUMP AT LEAST A FEW DEGREES AS THESE TROUGHS
PASS EVEN IN THE MIDDLE OF THE NIGHT...BUT GIVEN THIS IS STILL 3
PERIODS OUT WILL NOT ADVERTISE A NON-DIURNAL TEMP CURVE AT THIS
TIME. FOR ACTUAL LOWS...MADE LITTLE CHANGE WITH LOW 20S ADVERTISED ALL
AREAS...ALTHOUGH WOULD NOT BE SURPRISED TO SEE SOUTHEAST AREAS
OVER THE DEEPER SNOW COVER TRY DROPPING INTO THE TEENS BEFORE
MIXING BEHIND THE PASSING TROUGH LINE PICKS UP A BIT. ON ONE LAST
FRIDAY NIGHT NOTE...THE SREF VISIBILITY PROGS ARE SUGGESTING SOME
FOG DEVELOPMENT OVER THE MELTING SNOW PACK DURING THE NIGHT...BUT
THINKING THE WESTERLY WINDS BEHIND THE TROUGH AXIS SHOULD PROVE
UNFAVORABLE FOR ANY FOG WORTH MENTIONING.
SATURDAY/SATURDAY NIGHT...CONFIDENCE IS RATHER HIGH IN A DRY 24
HOURS...AS MID LEVEL HEIGHTS START TO RISE A BIT AS MID LEVEL
TROUGHING MOVES OFF THE TO THE EAST. AS IT DOES SO...COULD SEE
ADDITIONAL SNOW BANDS DEVELOP NEAR/MAINLY EAST OF THE IA/NEB BORDER
DURING THE DAY...BUT THIS SHOULD STAY SQUARELY EAST OF OUR CWA. IN
THE LOW LEVELS...WESTERLY WINDS WILL PICK UP A BIT TOWARD BREEZY
TERRITORY DURING THE DAY...WITH SUSTAINED SPEEDS INCREASING TO AT
LEAST 15-20 MPH FOR A FEW HOURS. NEEDLESS TO SAY...THE BATTLE
BETWEEN THIS WARMING DOWNSLOPE FLOW AND THE LINGERING SNOW PACK
ACROSS MAINLY THE SOUTHEAST 1/2 OF THE CWA MAKES FOR A TRICKY AND
SOMEWHAT LOW CONFIDENCE HIGH TEMPERATURE FORECAST. FOR NOW...WILL
KEEP THEME SIMILAR TO PREVIOUS WITH MAINLY UPPER 40S/NEAR 50 WHERE
SNOW IS NONE/MINIMAL...AND ONLY LOW 40S IN SOUTHEAST COUNTIES
WHERE IT IS DEEPER. COULD EASILY SEE SOME 5+ DEGREE ERRORS HERE
DEPENDING ON HOW MUCH EFFECT THE SNOW FIELD HAS. ALTHOUGH NOT AS
STRONG AS DURING THE DAY...PERSISTENT STEADY WESTERLY BREEZES
OVERNIGHT SHOULD AGAIN HOLD LOW TEMPS UP IN THE LOW 20S MOST ALL
AREAS.
SUNDAY/SUNDAY NIGHT...FAIRLY UNEVENTFUL NORTHWEST FLOW ALOFT
CONTINUES...DESPITE A FEW VERY LOW AMPLITUDE SHORTWAVE TROUGHS
PASSING THROUGH THE FLOW. LOOKS AT THIS POINT LIKE ANY PRECIP
SHOULD FOCUS AT LEAST LEAST FEW HUNDRED MILES NORTHEAST AND/OR
SOUTH OF THE CWA. ALTHOUGH TEMPS AT 850MB SHOULD AVERAGE A BIT
WARMER THAN SATURDAY...BREEZES WILL LIKELY BE A BIT LIGHTER AND
MORE FROM THE SOUTHWEST. THE NET RESULT IS ALMOST IDENTICALLY
FORECAST HIGH TEMPERATURES TO SATURDAY IN MOST AREAS...WITH MAINLY
UPPER 40S...EXCEPT SLIGHTLY COOLER MID 40S OVER THE DEEPER SNOW.
MONDAY/MONDAY NIGHT...THE REGION REMAINS UNDER NORTHWEST FLOW
BETWEEN A RIDGE BUILDING OVER THE WESTERN CONUS...AND THE NEXT IN
A PARADE OF CHANNELED SHORTWAVE TROUGHS SLIDING SOUTHEAST OUT OF
CANADA ACROSS THE DAKOTAS/IA. AGAIN...ANY PRECIPITATION ALONG THIS
SHORTWAVE AXIS SHOULD FOCUS AT LEAST A FEW HUNDRED MILES TO OUR
EAST...WHILE WE REMAIN IN THE MILDER AIR ON THE WARMER SIDE OF THE
UPPER JET. HIGH TEMPS FOLLOW CLOSELY TO ALLBLEND MODEL
CONSENSUS...WITH UPPER 40S MOST NEB ZONES AND LOW/MID 50S
SOUTHWEST.
TUESDAY/TUESDAY NIGHT...THE FLOW ALOFT TRANSITIONS MORE ZONAL IN
THE WAKE OF THE VIGOROUS MIDWEST SHORTWAVE TROUGH THAT QUICKLY
DEPARTS TOWARD THE MID-ATLANTIC REGION. WITH LITTLE FORESEEABLE
CHANGE IN THE LOW LEVEL TEMPERATURE FIELDS...HIGH TEMPS ARE
FORECAST VERY SIMILAR TO MONDAY...RANGING FROM MID 40S NORTHEAST
TO LOW 50S SOUTHWEST.
WEDNESDAY/WEDNESDAY NIGHT...THINGS START TO TURN A BIT MORE
INTERESTING ALOFT...AS BOTH THE ECWMF/GFS ARE IN SURPRISINGLY GOOD
AGREEMENT AS A SLOWLY DEEPENING BUT PROGRESSIVE SHORTWAVE TROUGH
DROPS OUT OF THE NORTHERN ROCKIES TOWARD THE NORTHERN/CENTRAL
PLAINS...ABUT AT LEAST FOR NOW OUR LOCAL PRECIP CHANCES APPEAR
QUITE MINIMAL WITH BETTER FORCING/MOISTURE FOCUSING OFF TO OUR
EAST/SOUTHEAST...ALTHOUGH IT COULD BE A CLOSE CALL ESPECIALLY PER
THE GFS. SOMETHING TO WATCH. MODEL CONSENSUS HIGHS ARE YET AGAIN A
NEAR COPY OF THE PREVIOUS FEW DAYS...UPPER 40S NORTHEAST TO MID
50S SOUTHWEST.
THURSDAY...COULD SEE AT LEAST A SLIGHT COOL-DOWN BEHIND A SURFACE
COLD FRONT THAT PASSES THROUGH WEDNESDAY NIGHT...AND ITS VERY
POSSIBLE THAT CURRENTLY FORECAST TEMPS MAINLY IN THE UPPER 40S TO
LOW 50S COULD BE A BIT TOO WARM. ALOFT...THE AFOREMENTIONED UPPER
WAVE STARTS TO PASS EAST/SOUTHEAST DURING THE DAY...PRESUMABLY
KEEPING PRECIP CHANCES QUITE MINIMAL.
LOOKING BEYOND THE OFFICIAL 7-DAY FORECAST PERIOD...THERE ARE
SUGGESTIONS THAT NEXT WEEKEND COULD HOLD OUR NEXT POTENTIALLY
DECENT PRECIP CHANCES...BUT PLENTY TO IRON OUT HERE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
0944 PM UPDATE/AVIATION...BRYANT
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1201 AM CST WED JAN 30 2013
.AVIATION...06Z KGRI TAF. THE BACK END OF THE SNOW SHIELD WILL
CONTINUE TO SLIDE SOUTHEAST AND EXPECT THE SNOW SHOULD COME TO AN
END AT KGRI BY AROUND 08Z. VISIBILITY AND CEILINGS SHOULD ALSO
SHOW SOME IMPROVEMENT ONCE THE SNOW MOVES OUT. HOWEVER...THE WIND
WILL REMAIN GUSTY OUT OF THE NORTHWEST THROUGH AT LEAST MID
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1045 PM CST TUE JAN 29 2013/
UPDATE...RADAR RETURNS FROM KUEX THROUGH THE PAST HOUR OR SO
INDICATE BANDED PRECIPITATION CONTINUING OVER THE SOUTHEASTERN
ONE-THIRD OF THE CWA. ADVISORY WAS RIGHT ON FOR THE MOST
PART...EXCEPT INCREASED SNOWFALL RATES WERE ALSO BEING INDICATED
OVER NORTH CENTRAL KANSAS AND AS A RESULT...OPTED TO EXTEND THE
ADVISORY TO ALSO INCLUDE MITCHELL...OSBORNE...AND SMITH COUNTIES
IN KANSAS...AS WELL AS WEBSTER COUNTY IN NEBRASKA. ALSO...ALTHOUGH
IT APPEARS THE HEAVIEST SNOWFALL SHOULD BE COMING TO AN END AROUND
01Z...THE ENDING TIME APPEARED A LITTLE TOO CLOSE FOR COMFORT WITH
RESPECT WITH THE HEADLINE. IN ADDITION...AN INCREASING NORTH WIND
IS ALSO EXPECTED TO PROMOTE RESTRICTED VISIBILITY IN BLOWING SNOW
THROUGH SUNRISE WEDNESDAY. GIVEN ALL THIS...WENT AHEAD AND ALSO
EXTENDED THE ADVISORY TO 12Z.
PREV DISCUSSION... /ISSUED 728 PM CST TUE JAN 29 2013/
UPDATE...EVENING UPPER AIR ANALYSIS INDICATES A LONGWAVE TROUGH
OVER THE CENTRAL CONUS...WITH RIDGING OVER THE EAST AND WEST. MID
AND UPPER LEVEL JET ENERGY EXTENDS SOUTH/SOUTHEAST FROM SOUTHWEST
CANADA INTO THE FOUR CORNERS REGION...AND THEN EAST INTO THE
SOUTHERN PLAINS BEFORE TURNING NORTHEAST ACROSS PORTIONS OF THE
CENTRAL PLAINS AND MISSISSIPPI VALLEY. ALTHOUGH THE PRIMARY AXIS
OF THIS JET ENERGY REMAIN JUST EAST/SOUTHEAST OF OUR CWA...RAP
DATA DOES SUGGEST WIND SPEEDS GENERALLY RANGING FROM 50-100KTS IN
EXISTENCE FROM WEST TO EAST ACROSS OUR CWA AROUND 400MB...WITH THE
STRONGEST WIND RESIDING ACROSS OUR EAST. WATER VAPOR IMAGERY SHOWS
INCREASED VALUES OF MID LEVEL MOISTURE EXTENDING FROM EASTERN
TEXAS...NORTHEAST INTO THE MID MISSISSIPPI VALLEY...AND A MID
LEVEL DRY INTRUSION WORKING INTO THE CENTRAL PLAINS. AT THE
SURFACE A COLD FRONT IS NOTED EXTENDING FROM CENTRAL
MISSOURI...SOUTHWEST INTO PORTIONS OF KANSAS...OKLAHOMA AND TEXAS.
OUR CWA IS CURRENTLY ON THE BACK SIDE OF THIS FRONT WITH A
NORTHERLY LOW LEVEL WIND FIELD PREVAILING ACROSS THE AREA AS A
RESULT. RADAR DATA FROM KUEX INDICATES BANDED PRECIPITATION OVER
THE SOUTHEASTERN HALF OF OUR CWA...HOWEVER COMMUNICATION WITH
OBSERVERS HAVE YIELDED LITTLE MORE THAN TRACE REPORTS OF SNOWFALL
ACCUMULATION THIS EVENING...ALTHOUGH ACCUMULATION IS UNDOUBTEDLY
BEGINNING TO OCCUR ALONG AND EAST OF HIGHWAY 281 NOW.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST PORTIONS OF THE LONGWAVE TROUGH NEAR OUR AREA WILL
STRENGTHEN INTO A SHORT WAVE FEATURE AS IT PUSHES OVER PORTIONS OF
NEBRASKA AND KANSAS...AND EVENTUALLY INTO IOWA AND MISSOURI
TONIGHT. AS MID LEVEL VORTICITY INCREASES WITH THE STRENGTHENING
MID LEVEL SHORT WAVE...SO WILL MID LEVEL DEFORMATION TO THE
WEST/NORTHWEST OF THE MID LEVEL SHORT WAVE AXIS...WITH THE PRIMARY
AXIS OF MID LEVEL DEFORMATION EXPECTED TO PERSIST FROM EASTERN
NEBRASKA...INTO PORTIONS OF SOUTH CENTRAL NEBRASKA AND NORTH
CENTRAL KANSAS THIS EVENING...AND THEN EAST INTO WESTERN IOWA AND
SOUTHEASTERN NEBRASKA BY 06Z TONIGHT. THIS AXIS OF DEFORMATION AND
RESULTANT MID LEVEL FRONTOGENESIS...PRIMARILY NEAR 700MB...WILL
CONTINUE TO PROVIDE BANDED PRECIPITATION ACROSS PORTIONS OF OUR
AREA THROUGH AT LEAST 06Z...WITH THE EAST/SOUTHEASTERN PORTIONS OF OUR
CWA STILL UNDER THE GUN TO RECEIVE A DECENT ROUND OF FRESH
SNOWFALL THIS EVENING. FORECAST CROSS SECTIONS ALSO INDICATE A
WEAK ZONE OF -EPV WILL PERIODICALLY EXIST JUST ABOVE THE MID LEVEL
FRONTOGENESIS THIS EVENING...WHICH INDICATES AT LEAST SOME SLANT-
WISE CONVECTION AND A POSSIBILITY FOR INCREASED PRECIPITATION
RATES.
THE CURRENT THINKING IS THAT THIS AREA OF BANDED PRECIPITATION
WILL CONTINUE SHIFTING EAST/NORTHEAST ALONG WITH THE PRIMARY AXIS
OF MID LEVEL FRONTOGENESIS THROUGH TONIGHT...WITH PRECIPITATION
RATES INCREASING AS THE AFOREMENTIONED MID LEVEL FRONTOGENESIS
ALSO INTENSIFIES ACROSS EAST/SOUTHEASTERN PORTIONS OF OUR CWA.
PRECIPITATION SHOULD THEN TAPER OFF ACROSS OUR CWA STARTING AROUND
06Z AS THE PRIMARY AXIS OF MID LEVEL FRONTOGENESIS ALSO MOVES EAST
OF OUR AREA. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC...SREF-MEAN...RAP...HRRR...AND 4KM WRF-
NMM. EXACT LIQUID PRECIPITATION AMOUNTS VARY FROM MODEL TO
MODEL...BUT IN GENERAL THEY AVERAGE BETWEEN 0.1" AND 0.2" ACROSS
OUR SOUTHEAST. WITH LOWER TROPOSPHERIC TEMPERATURE EXPECTED TO
AVERAGE IN THE UPPER 20S TO NEAR 30 DEGREES F...WILL GO AHEAD AND
ASSUME AN AVERAGE SNOW-WATER RATIO OF 12:1...WHICH PRESENTS
SNOWFALL ACCUMULATION GENERALLY IN THE 1-2.5" RANGE. GIVEN THE
POTENTIAL FOR MODEST SLANT-WISE CONVECTION HOWEVER...WILL GO AHEAD
AND ADD ANOTHER INCH TO THE MODEL OUTPUT WHICH PROVIDES SNOWFALL
ACCUMULATION CLOSER TO THE 2-4" RANGE.
IN ADDITION TO THE SNOWFALL...LOW LEVEL PRESSURE RISES BEHIND THE
LOW LEVEL BAROCLINIC ZONE...CURRENTLY TO OUR SOUTH...ARE EXPECTED
TO INDUCE A STRENGTHENING LOW LEVEL PRESSURE GRADIENT TONIGHT.
GUIDANCE FROM THE MET AND MAV SUGGEST A SUSTAINED WIND AVERAGING
BETWEEN 15 AND 20KTS...WITH LOCALLY HIGHER GUSTS...WILL BE COMMON
ACROSS OUR CWA DURING THE SNOWFALL WHICH WILL CERTAINLY CREATE
SOME VISIBILITY RESTRICTION IN BLOWING SNOW.
OVERALL THE TIMING AND POSITION OF THE CURRENT WINTER WEATHER
ADVISORY ARE IN GREAT SHAPE...SO MADE NO CHANGES THERE. OUR
FORECAST SNOWFALL AMOUNTS DID SEEM A TOUCH ON THE HIGH SIDE BASED
ON THE LATEST MODEL OUTPUT...SO DID GO AHEAD AND DECREASE SNOWFALL
ACCUMULATION DOWN INTO THE 2-4" RANGE FOR THE ADVISORY AREA.
REMAINDER OF THE FORECAST REMAINS IN GREAT SHAPE WITH ONLY MINOR
CHANGES MADE TO HOURLY TEMPERATURE...WIND AND DEWPOINTS GRIDS TO
BETTER REFLECT CURRENT CONDITIONS.
PREV DISCUSSION... /ISSUED 358 PM CST TUE JAN 29 2013/
SHORT TERM...TONIGHT AND WEDNESDAY.
HIGHLY AMPLIFIED MEAN TROUGH IS HEADING EAST WITH THE AXIS CROSSING
INTO THE HIGH PLAINS. STRONG JET AHEAD OF THIS AXIS WITH STIFF
MID-LEVEL FRONTOGENETIC FORCING PREDICTED TO RAMP UP THIS EVENING.
THIS IS SUPPORTED BY THE NAM...HRRR...ECMWF...AND GFS...ALL PLACING
DECENT QPF AMOUNTS IN THE EAST/SOUTHEAST PART OF THE CWA AT THE VERY
LEAST.
THIS AGREEMENT AMONG MODELS HAS LED ME TO INCREASE CHANCES OF
PRECIPITATION EVEN MORE. SOUNDINGS INDICATE THAT THIS WILL BE A SNOW
EVENT AND HAVE GONE WITH ONLY SNOW AS THE PRECIPITATION TYPE...AS
OPPOSED TO MENTIONING RAIN AT ONSET. THE HRRR INDICATE4D QUITE A RAMP
UP IN QPF PRODUCTION BY EARLY AFTERNOON...WHICH PROMPTED ME TO GO
WITH AN ADVISORY FOR MOST OF OUR EASTERN CWA. I FELT INCLINED TO DO
THIS AS NORTH/NORTHWEST WIND WILL RAMP UP CONSIDERABLY TONIGHT AS
THE SURFACE PRESSURE GRADIENT INCREASES. I INCREASED WIND SPEEDS A
BIT MORE FROM THE PREVIOUS FORECAST FOR TONIGHT INTO WEDNESDAY. SNOW
SHOULD WIND DOWN FAIRLY QUICKLY AS THE TROUGH AXIS HEADS TO THE EAST
BY THE OVERNIGHT. LEFT THE SLIGHT CHANCE OF FLURRIES IN OUR
NORTHEAST FOR WEDNESDAY MORNING...BUT I DID NOTICE THE NAM PULLING
BACK A LITTLE ON STRATUS...WHICH USUALLY INDICATES A LACK OF FLURRY
POTENTIAL...BUT CLOSE ENOUGH FOR ME TO LEAVE IN FOR NOW. WIND SHOULD
REMAIN BELOW WIND ADVISORY CRITERIA FOR WEDNESDAY...ALTHOUGH OUR FAR
NORTH MAY FLIRT WITH IT...JUDGING BY PREDICTED MOMENTUM TRANSFER.
KEPT SKY COVER GENERALLY CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS...ESPECIALLY IN THE SOUTH BY AFTERNOON. KEPT TEMPERATURES THE
SAME FOR TONIGHT AND WEDNESDAY FROM PREVIOUS FORECAST AS THEY LOOKED
LIKE THEY WERE RIGHT ON TARGET.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. MAIN FORECAST CONCERN
IN THE EXTENDED WILL BE THE TEMPERATURES.
STARTING WED EVENING...THE BIG PICTURE SHOWS THE CENTRAL U.S. IN
NORTHWEST FLOW AS THE UPPER TROUGH IS SLATED TO BE MOVING INTO THE
MIDWEST WITH RIDGING MOVING ONTO THE PACIFIC NORTHWEST COAST. AS THE
WORK WEEK ROLLS ALONG IT APPEARS WE WILL PRETTY MUCH STAY IN THIS
TYPE OF FLOW WITH OVERALL RIDGING TO THE WEST AND TROUGHING EAST.
WILL MOST LIKELY HAVE A FEW CLIPPER LIKE WAVES SLIDE THROUGH OUR
REGION UNDER THIS TYPE OF PATTERN AND THE QUESTION IS WILL THEY
BRING ANY ADDITIONAL PRECIPITATION CHANCES. BASIC ANSWER IS NO
ALTHOUGH WE DO HAVE A CHANCE OF FLURRIES MENTIONED FOR WED NIGHT AND
THURSDAY IN THE CURRENT FORECAST AND WILL GO AHEAD AND KEEP THEM IN
GIVEN SUFFICIENT MOISTURE AND COLDER TEMPERATURES NOTED IN MODEL
FORECAST SOUNDINGS. OTHERWISE WILL LEAVE THE REST OF THE FORECAST
DRY ALTHOUGH SOME LIGHT PRECIPITATION NOT TOTALLY OUT OF THE
QUESTION FOR FRIDAY.
AS FAR AS TEMPERATURES GO...IT WILL REMAIN QUITE CHILLY WED NIGHT
INTO FRIDAY MORNING AS ADDITIONAL COLD AIR SLIDES DOWN FROM THE
NORTH...ALTHOUGH THE BITTER COLD AIR SHOULD REMAIN JUST NORTHEAST OF
THE CWA. STOUT NORTHWEST WINDS ARE ALSO EXPECTED AGAIN FOR THURSDAY
AFTERNOON AS WE SIT BETWEEN 1038 MB HIGH PRESSURE OVER MONTANA/NDAK
AND LOW PRESSURE ACROSS MISSOURI AND KANSAS. FRIDAY MORNING MIGHT
BE THE COLDEST DAY OF THE WEEK DEPENDING ON WHETHER HIGH PRESSURE
DROPS RIGHT OVER THE TOP OF US OR SLIDES A LITTLE TO THE EAST IN
WHICH CASE WE MIGHT HAVE A MORE CLOUD COVER AND LIGHT SOUTHERLY
FLOW.
GOING INTO THE WEEKEND HEIGHTS BEGIN TO RISE AS WESTERN RIDGE STARTS
TO MOVE EAST AND AT THIS POINT APPEARS BOTH SAT AND SUNDAY SHOULD BE
CLOSE TO 50 DEGREES. ANOTHER WEAK FRONT IS EXPECTED TO PUSH ACROSS
SUNDAY NIGHT OR MONDAY WITH HIGH TEMPERATURES FALLING A TAD BUT
STILL ABOVE SEASONAL LEVELS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR NEZ049-063-
064-076-077-085>087.
KS...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR KSZ006-007-
018-019.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1045 PM CST TUE JAN 29 2013
.UPDATE...RADAR RETURNS FROM KUEX THROUGH THE PAST HOUR OR SO
INDICATE BANDED PRECIPITATION CONTINUING OVER THE SOUTHEASTERN
ONE-THIRD OF THE CWA. ADVISORY WAS RIGHT ON FOR THE MOST
PART...EXCEPT INCREASED SNOWFALL RATES WERE ALSO BEING INDICATED
OVER NORTH CENTRAL KANSAS AND AS A RESULT...OPTED TO EXTEND THE
ADVISORY TO ALSO INCLUDE MITCHELL...OSBORNE...AND SMITH COUNTIES
IN KANSAS...AS WELL AS WEBSTER COUNTY IN NEBRASKA. ALSO...ALTHOUGH
IT APPEARS THE HEAVIEST SNOWFALL SHOULD BE COMING TO AN END AROUND
01Z...THE ENDING TIME APPEARED A LITTLE TOO CLOSE FOR COMFORT WITH
RESPECT WITH THE HEADLINE. IN ADDITION...AN INCREASING NORTH WIND
IS ALSO EXPECTED TO PROMOTE RESTRICTED VISIBILITY IN BLOWING SNOW
THROUGH SUNRISE WEDNESDAY. GIVEN ALL THIS...WENT AHEAD AND ALSO
EXTENDED THE ADVISORY TO 12Z.
&&
.PREV DISCUSSION... /ISSUED 728 PM CST TUE JAN 29 2013/
UPDATE...EVENING UPPER AIR ANALYSIS INDICATES A LONGWAVE TROUGH
OVER THE CENTRAL CONUS...WITH RIDGING OVER THE EAST AND WEST. MID
AND UPPER LEVEL JET ENERGY EXTENDS SOUTH/SOUTHEAST FROM SOUTHWEST
CANADA INTO THE FOUR CORNERS REGION...AND THEN EAST INTO THE
SOUTHERN PLAINS BEFORE TURNING NORTHEAST ACROSS PORTIONS OF THE
CENTRAL PLAINS AND MISSISSIPPI VALLEY. ALTHOUGH THE PRIMARY AXIS
OF THIS JET ENERGY REMAIN JUST EAST/SOUTHEAST OF OUR CWA...RAP
DATA DOES SUGGEST WIND SPEEDS GENERALLY RANGING FROM 50-100KTS IN
EXISTENCE FROM WEST TO EAST ACROSS OUR CWA AROUND 400MB...WITH THE
STRONGEST WIND RESIDING ACROSS OUR EAST. WATER VAPOR IMAGERY SHOWS
INCREASED VALUES OF MID LEVEL MOISTURE EXTENDING FROM EASTERN
TEXAS...NORTHEAST INTO THE MID MISSISSIPPI VALLEY...AND A MID
LEVEL DRY INTRUSION WORKING INTO THE CENTRAL PLAINS. AT THE
SURFACE A COLD FRONT IS NOTED EXTENDING FROM CENTRAL
MISSOURI...SOUTHWEST INTO PORTIONS OF KANSAS...OKLAHOMA AND TEXAS.
OUR CWA IS CURRENTLY ON THE BACK SIDE OF THIS FRONT WITH A
NORTHERLY LOW LEVEL WIND FIELD PREVAILING ACROSS THE AREA AS A
RESULT. RADAR DATA FROM KUEX INDICATES BANDED PRECIPITATION OVER
THE SOUTHEASTERN HALF OF OUR CWA...HOWEVER COMMUNICATION WITH
OBSERVERS HAVE YIELDED LITTLE MORE THAN TRACE REPORTS OF SNOWFALL
ACCUMULATION THIS EVENING...ALTHOUGH ACCUMULATION IS UNDOUBTEDLY
BEGINNING TO OCCUR ALONG AND EAST OF HIGHWAY 281 NOW.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST PORTIONS OF THE LONGWAVE TROUGH NEAR OUR AREA WILL
STRENGTHEN INTO A SHORT WAVE FEATURE AS IT PUSHES OVER PORTIONS OF
NEBRASKA AND KANSAS...AND EVENTUALLY INTO IOWA AND MISSOURI
TONIGHT. AS MID LEVEL VORTICITY INCREASES WITH THE STRENGTHENING
MID LEVEL SHORT WAVE...SO WILL MID LEVEL DEFORMATION TO THE
WEST/NORTHWEST OF THE MID LEVEL SHORT WAVE AXIS...WITH THE PRIMARY
AXIS OF MID LEVEL DEFORMATION EXPECTED TO PERSIST FROM EASTERN
NEBRASKA...INTO PORTIONS OF SOUTH CENTRAL NEBRASKA AND NORTH
CENTRAL KANSAS THIS EVENING...AND THEN EAST INTO WESTERN IOWA AND
SOUTHEASTERN NEBRASKA BY 06Z TONIGHT. THIS AXIS OF DEFORMATION AND
RESULTANT MID LEVEL FRONTOGENESIS...PRIMARILY NEAR 700MB...WILL
CONTINUE TO PROVIDE BANDED PRECIPITATION ACROSS PORTIONS OF OUR
AREA THROUGH AT LEAST 06Z...WITH THE EAST/SOUTHEASTERN PORTIONS OF OUR
CWA STILL UNDER THE GUN TO RECEIVE A DECENT ROUND OF FRESH
SNOWFALL THIS EVENING. FORECAST CROSS SECTIONS ALSO INDICATE A
WEAK ZONE OF -EPV WILL PERIODICALLY EXIST JUST ABOVE THE MID LEVEL
FRONTOGENESIS THIS EVENING...WHICH INDICATES AT LEAST SOME SLANT-
WISE CONVECTION AND A POSSIBILITY FOR INCREASED PRECIPITATION
RATES.
THE CURRENT THINKING IS THAT THIS AREA OF BANDED PRECIPITATION
WILL CONTINUE SHIFTING EAST/NORTHEAST ALONG WITH THE PRIMARY AXIS
OF MID LEVEL FRONTOGENESIS THROUGH TONIGHT...WITH PRECIPITATION
RATES INCREASING AS THE AFOREMENTIONED MID LEVEL FRONTOGENESIS
ALSO INTENSIFIES ACROSS EAST/SOUTHEASTERN PORTIONS OF OUR CWA.
PRECIPITATION SHOULD THEN TAPER OFF ACROSS OUR CWA STARTING AROUND
06Z AS THE PRIMARY AXIS OF MID LEVEL FRONTOGENESIS ALSO MOVES EAST
OF OUR AREA. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC...SREF-MEAN...RAP...HRRR...AND 4KM WRF-
NMM. EXACT LIQUID PRECIPITATION AMOUNTS VARY FROM MODEL TO
MODEL...BUT IN GENERAL THEY AVERAGE BETWEEN 0.1" AND 0.2" ACROSS
OUR SOUTHEAST. WITH LOWER TROPOSPHERIC TEMPERATURE EXPECTED TO
AVERAGE IN THE UPPER 20S TO NEAR 30 DEGREES F...WILL GO AHEAD AND
ASSUME AN AVERAGE SNOW-WATER RATIO OF 12:1...WHICH PRESENTS
SNOWFALL ACCUMULATION GENERALLY IN THE 1-2.5" RANGE. GIVEN THE
POTENTIAL FOR MODEST SLANT-WISE CONVECTION HOWEVER...WILL GO AHEAD
AND ADD ANOTHER INCH TO THE MODEL OUTPUT WHICH PROVIDES SNOWFALL
ACCUMULATION CLOSER TO THE 2-4" RANGE.
IN ADDITION TO THE SNOWFALL...LOW LEVEL PRESSURE RISES BEHIND THE
LOW LEVEL BAROCLINIC ZONE...CURRENTLY TO OUR SOUTH...ARE EXPECTED
TO INDUCE A STRENGTHENING LOW LEVEL PRESSURE GRADIENT TONIGHT.
GUIDANCE FROM THE MET AND MAV SUGGEST A SUSTAINED WIND AVERAGING
BETWEEN 15 AND 20KTS...WITH LOCALLY HIGHER GUSTS...WILL BE COMMON
ACROSS OUR CWA DURING THE SNOWFALL WHICH WILL CERTAINLY CREATE
SOME VISIBILITY RESTRICTION IN BLOWING SNOW.
OVERALL THE TIMING AND POSITION OF THE CURRENT WINTER WEATHER
ADVISORY ARE IN GREAT SHAPE...SO MADE NO CHANGES THERE. OUR
FORECAST SNOWFALL AMOUNTS DID SEEM A TOUCH ON THE HIGH SIDE BASED
ON THE LATEST MODEL OUTPUT...SO DID GO AHEAD AND DECREASE SNOWFALL
ACCUMULATION DOWN INTO THE 2-4" RANGE FOR THE ADVISORY AREA.
REMAINDER OF THE FORECAST REMAINS IN GREAT SHAPE WITH ONLY MINOR
CHANGES MADE TO HOURLY TEMPERATURE...WIND AND DEWPOINTS GRIDS TO
BETTER REFLECT CURRENT CONDITIONS.
PREV DISCUSSION... /ISSUED 533 PM CST TUE JAN 29 2013/
AVIATION...00Z KGRI TAF. MVFR CEILINGS EXPECTED THROUGH THE FIRST
HALF OF THE TAF PERIOD WITH LIGHT SNOW ALSO EXPECTED TO PERSIST
THROUGH VERY EARLY WEDNESDAY MORNING. VISIBILITY RESTRICTION IN
BLOWING SNOW WILL ALSO BE POSSIBLE LATER TONIGHT AS THE NORTH
WIND INTENSIFIES. VFR CONDITIONS SHOULD BE RESTORED SHORTLY AFTER
SUNRISE WEDNESDAY.
PREV DISCUSSION... /ISSUED 358 PM CST TUE JAN 29 2013/
SHORT TERM...TONIGHT AND WEDNESDAY.
HIGHLY AMPLIFIED MEAN TROUGH IS HEADING EAST WITH THE AXIS CROSSING
INTO THE HIGH PLAINS. STRONG JET AHEAD OF THIS AXIS WITH STIFF
MID-LEVEL FRONTOGENETIC FORCING PREDICTED TO RAMP UP THIS EVENING.
THIS IS SUPPORTED BY THE NAM...HRRR...ECMWF...AND GFS...ALL PLACING
DECENT QPF AMOUNTS IN THE EAST/SOUTHEAST PART OF THE CWA AT THE VERY
LEAST.
THIS AGREEMENT AMONG MODELS HAS LED ME TO INCREASE CHANCES OF
PRECIPITATION EVEN MORE. SOUNDINGS INDICATE THAT THIS WILL BE A SNOW
EVENT AND HAVE GONE WITH ONLY SNOW AS THE PRECIPITATION TYPE...AS
OPPOSED TO MENTIONING RAIN AT ONSET. THE HRRR INDICATE4D QUITE A RAMP
UP IN QPF PRODUCTION BY EARLY AFTERNOON...WHICH PROMPTED ME TO GO
WITH AN ADVISORY FOR MOST OF OUR EASTERN CWA. I FELT INCLINED TO DO
THIS AS NORTH/NORTHWEST WIND WILL RAMP UP CONSIDERABLY TONIGHT AS
THE SURFACE PRESSURE GRADIENT INCREASES. I INCREASED WIND SPEEDS A
BIT MORE FROM THE PREVIOUS FORECAST FOR TONIGHT INTO WEDNESDAY. SNOW
SHOULD WIND DOWN FAIRLY QUICKLY AS THE TROUGH AXIS HEADS TO THE EAST
BY THE OVERNIGHT. LEFT THE SLIGHT CHANCE OF FLURRIES IN OUR
NORTHEAST FOR WEDNESDAY MORNING...BUT I DID NOTICE THE NAM PULLING
BACK A LITTLE ON STRATUS...WHICH USUALLY INDICATES A LACK OF FLURRY
POTENTIAL...BUT CLOSE ENOUGH FOR ME TO LEAVE IN FOR NOW. WIND SHOULD
REMAIN BELOW WIND ADVISORY CRITERIA FOR WEDNESDAY...ALTHOUGH OUR FAR
NORTH MAY FLIRT WITH IT...JUDGING BY PREDICTED MOMENTUM TRANSFER.
KEPT SKY COVER GENERALLY CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS...ESPECIALLY IN THE SOUTH BY AFTERNOON. KEPT TEMPERATURES THE
SAME FOR TONIGHT AND WEDNESDAY FROM PREVIOUS FORECAST AS THEY LOOKED
LIKE THEY WERE RIGHT ON TARGET.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. MAIN FORECAST CONCERN
IN THE EXTENDED WILL BE THE TEMPERATURES.
STARTING WED EVENING...THE BIG PICTURE SHOWS THE CENTRAL U.S. IN
NORTHWEST FLOW AS THE UPPER TROUGH IS SLATED TO BE MOVING INTO THE
MIDWEST WITH RIDGING MOVING ONTO THE PACIFIC NORTHWEST COAST. AS THE
WORK WEEK ROLLS ALONG IT APPEARS WE WILL PRETTY MUCH STAY IN THIS
TYPE OF FLOW WITH OVERALL RIDGING TO THE WEST AND TROUGHING EAST.
WILL MOST LIKELY HAVE A FEW CLIPPER LIKE WAVES SLIDE THROUGH OUR
REGION UNDER THIS TYPE OF PATTERN AND THE QUESTION IS WILL THEY
BRING ANY ADDITIONAL PRECIPITATION CHANCES. BASIC ANSWER IS NO
ALTHOUGH WE DO HAVE A CHANCE OF FLURRIES MENTIONED FOR WED NIGHT AND
THURSDAY IN THE CURRENT FORECAST AND WILL GO AHEAD AND KEEP THEM IN
GIVEN SUFFICIENT MOISTURE AND COLDER TEMPERATURES NOTED IN MODEL
FORECAST SOUNDINGS. OTHERWISE WILL LEAVE THE REST OF THE FORECAST
DRY ALTHOUGH SOME LIGHT PRECIPITATION NOT TOTALLY OUT OF THE
QUESTION FOR FRIDAY.
AS FAR AS TEMPERATURES GO...IT WILL REMAIN QUITE CHILLY WED NIGHT
INTO FRIDAY MORNING AS ADDITIONAL COLD AIR SLIDES DOWN FROM THE
NORTH...ALTHOUGH THE BITTER COLD AIR SHOULD REMAIN JUST NORTHEAST OF
THE CWA. STOUT NORTHWEST WINDS ARE ALSO EXPECTED AGAIN FOR THURSDAY
AFTERNOON AS WE SIT BETWEEN 1038 MB HIGH PRESSURE OVER MONTANA/NDAK
AND LOW PRESSURE ACROSS MISSOURI AND KANSAS. FRIDAY MORNING MIGHT
BE THE COLDEST DAY OF THE WEEK DEPENDING ON WHETHER HIGH PRESSURE
DROPS RIGHT OVER THE TOP OF US OR SLIDES A LITTLE TO THE EAST IN
WHICH CASE WE MIGHT HAVE A MORE CLOUD COVER AND LIGHT SOUTHERLY
FLOW.
GOING INTO THE WEEKEND HEIGHTS BEGIN TO RISE AS WESTERN RIDGE STARTS
TO MOVE EAST AND AT THIS POINT APPEARS BOTH SAT AND SUNDAY SHOULD BE
CLOSE TO 50 DEGREES. ANOTHER WEAK FRONT IS EXPECTED TO PUSH ACROSS
SUNDAY NIGHT OR MONDAY WITH HIGH TEMPERATURES FALLING A TAD BUT
STILL ABOVE SEASONAL LEVELS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR NEZ049-063-
064-076-077-085>087.
KS...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR KSZ006-007-
018-019.
&&
$$
1045 PM UPDATE/0728 PM UPDATE/AVIATION...BRYANT
SHORT TERM...HEINLEIN
LONG TERM...EWALD
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
115 PM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
9 AM UPDATE...
YET ANOTHER UPDATE TO BUMP TEMPS DOWN AT KAVP WITH SENSOR READING
AROUND 4 DEGREES TOO WARM. NO OTHER CHGS NEEDED AT THIS TIME AS A
MAJOR WX EVENT IS IMPENDING FOR TONIGHT.
730 AM UPDATE...
QUICK UPDATE TO BUMP CURRENT TEMPS UP IN WYOMING/LACKAWANNA VLYS
AS KAVP IS NOW UP TO 62F. MESONET SITES IN THAT AREA ARE CURRENTLY
IN THE MID-50S THUS NOT OUT OF THE QUESTION THAT SCRANTON WILKES-
BARRE AIRPORT IS IN THE LOW 60S AS IT SITS AROUND 1000 FEET UP AND
WITH STRONG INVERSION IN PLACE PER KALY/KOKX 12Z RAOBS.
630 AM UPDATE...MINOR T/TD TWEEKS IN THE NEAR TERM...RAISING MAXES
BY A FEW DEG MAINLY FINGER LAKES AND CNTRL SRN TIER. ALSO ADDED
PC SKIES FOR PARTS OF THE RGN THIS MRNG. CRUDE XTRAPOLATION OF
LEADING PCPN SHIELD INDICATES ARRIVAL TIME ARND 1730Z INTO WRN STEUBEN.
WE`LL SEE IF THIS HOLDS. NO OTHER CHGS. PREV BLO...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCURRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FIELD YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALLOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
1230 PM UPDATE...
IFR CIGS AT AVP AND MVFR CIGS AT ELM BGM ITH WILL EXPAND AND MOVE
NORTH INTO SYR AND RME THIS AFTN. IN ADDITION RAIN WILL MOVE IN
AND COVER THE ENTIRE AREA BY 20Z. THIS AREA OF RAIN WILL CONTINUE
THROUGH MOST OF TONIGHT. AFTER THE RAIN STARTS VSBYS WILL ALSO
FALL TO MAINLY MVFR. A STRONG COLD FRONT WILL MOVE THROUGH BETWEEN
4 AND 6Z. RAIN WILL END AROUND 11Z BUT AT RME LAKE EFFECT SNOW
WILL START. MOST OF THIS WILL STAY NORTH OF THEM THOUGH WITH A
WEST FLOW BUT CIGS SHOULD STAY MVFR. WITH THE END OF THE RAIN
DRIER AIR WILL COME IN SCATTERING OUT THE MVFR AND IFR CIGS AND
VSBYS...AND BRINGING CONDITIONS BACK TO VFR.
AT RME WITH A STRONG LL INVERSION WIND SHEAR LIKELY. SFC WINDS
UPVALLEY FROM THE SOUTHEAST WHILE ABOVE THE INVERSION AT 2K FT
THEY ARE SW AT 50 TO 70 KTS.
WINDS AT THE REST OF THE SITES NOW GUSTING. SOUTH WINDS AT 15 G 25
KTS. SYR IS 5 KTS STRONGER. WITH THE COLD FRONT TONIGHT A SHIFT TO
THE WEST AT SIMILAR SPEEDS. AROUND 11Z WEST WINDS INCREASE TO 20
TO 30 KTS WITH HIGHER GUSTS. AGAIN SYR WILL BE THE STRONGEST.
.OUTLOOK...
THU AFTN TO SAT NGT...OCNL MVFR TO IFR IN LAKE EFFECT SNOW
SHOWERS.
SUN...A COLD FRONT WITH MVFR AND IFR SNOW FOLLOWED BY MORE LAKE
EFFECT SNOW SUN NGT TO MONDAY.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS 1 TO UP TO 2.5
INCHES WITH THE HEAVIEST RAIN AXIS FURTHER WEST ACROSS THE FINGER
LAKES AND CHEMUNG BASINS OF NY. WILL HAVE TWO BATCHES WITH THE
INITIAL BATCH ALREADY IN WRN PA AND WRN NY NOW. THIS FIRST BATCH
MOVES QUICKLY THROUGH THIS AFTN. RAINFALL THIS AFTN UP TO HALF AN
INCH. QUICK RESPONSE ON STREAMS BUT NO FLOODING INITIALLY. THE
COLD FRONT WILL COME THROUGH LATE EVE AND EARLY MORNING WITH MORE
HEAVY RAIN. ANOTHER QUICK INCH IN LESS THAN 6 HOURS WHICH WILL BE
MOSTLY RUNOFF. STREAMS AND RIVERS WILL RESPOND QUICKLY. FLASH
FLOODING POSSIBLE...FOLLOWED BY MINOR RIVER FLOODING.
FLOOD WATCH CONTINUES FOR ENTIRE CWA STARTING AT 4 PM INTO
THURSDAY MORNING. RIVER FLOOD WARNINGS JUST ISSUED FOR
WEST BRANCH DELAWARE RIVER AT WALTON
TIOUGHNIOGA RIVER AT CORTLAND
CHENANGO RIVER AT SHERBURNE
SUSQUEHANNA RIVER AT VESTAL
SUSQUEHANNA RIVER AT WAVERLY/SAYRE
SUSQUEHANNA RIVER AT TOWANDA
SUSQUEHANNA RIVER AT MESHOPPEN
SUSQUEHANNA RIVER NEAR WILKES-BARRE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
WIND ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR
PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
WIND ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR
NYZ015-016-022>025-044-045-055-056-062.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY
FOR NYZ009-017-018-036-037-046-057.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...PVN
SHORT TERM...
LONG TERM...TAC
AVIATION...TAC
HYDROLOGY...TAC/JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1028 AM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
9 AM UPDATE...
YET ANOTHER UPDATE TO BUMP TEMPS DOWN AT KAVP WITH SENSOR READING
AROUND 4 DEGREES TOO WARM. NO OTHER CHGS NEEDED AT THIS TIME AS A
MAJOR WX EVENT IS IMPENDING FOR TONIGHT.
730 AM UPDATE...
QUICK UPDATE TO BUMP CURRENT TEMPS UP IN WYOMING/LACKAWANNA VLYS
AS KAVP IS NOW UP TO 62F. MESONET SITES IN THAT AREA ARE CURRENTLY
IN THE MID-50S THUS NOT OUT OF THE QUESTION THAT SCRANTON WILKES-
BARRE AIRPORT IS IN THE LOW 60S AS IT SITS AROUND 1000 FEET UP AND
WITH STRONG INVERSION IN PLACE PER KALY/KOKX 12Z RAOBS.
630 AM UPDATE...MINOR T/TD TWEEKS IN THE NEAR TERM...RAISING MAXES
BY A FEW DEG MAINLY FINGER LAKES AND CNTRL SRN TIER. ALSO ADDED
PC SKIES FOR PARTS OF THE RGN THIS MRNG. CRUDE XTRAPOLATION OF
LEADING PCPN SHIELD INDICATES ARRIVAL TIME ARND 1730Z INTO WRN STEUBEN.
WE`LL SEE IF THIS HOLDS. NO OTHER CHGS. PREV BLO...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCURRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FIELD YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALLOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LK EFFECT SNOW STARTING OFF PD ACRS FAR NRN NY WL TRANSITION NORTH
OF THE REGION BY 06Z SATURDAY AS SFC RIDGE NOSES INTO AREA. WK UL
TROF WL MV THRU SAT AFTN WITH EC BEING STRONGEST WITH VORT MAX AND
GFS WEAKER. THEREFORE HV GONE WITH ONLY CHC POPS AT THIS TIME PER HPC
GUIDANCE. POPS WL INCREASE SAT NGT AND SUN AS ANOTHER WV AND ASSOC
SFC LOW DROPS THRU THE CWA THO ONLY TO BTWN 40-50%.
12Z GUIDANCE HAS COME INTO BETTER AGREEMENT WITH WV DROPPING INTO
NERN U.S. AND DVLPNG SFC LOPRES SUN AFTN/EVNG SOMEWHERE IN THE GULF
OF MAINE. ENERGY WL LKLY NOT TRANSFER OFF THE COAST QUICKLY ENUF TO
GIVE US A THREAT FOR WIDESPREAD SNOW FOR EARLY NEXT WEEK.
TEMPS DRG THE EXTNDD PORTION WL SETTLE OUT CLOSE TO SEASONAL VALUES.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
12Z WED UPDATE... ONE OF THE MAIN AVIATION IMPACTS THE NEXT 12-18
HRS WILL BE LLWS...AS A VERY STG LOW-LVL JET DVLPS OVER THE
RGN...WITH AN INVERSION ALSO IN PLACE IN THE LWST 2K FT...TO KEEP
THE STGST WINDS JUST OFF THE SFC. THIS HAZARD WAS CARRIED AT ALL
SITES. THERE IS SOME PSBLTY THAT WARMING SFC TEMPS THIS AFTN WILL
BE ENOUGH TO ERODE THE INVERSION...AND BRING STG GUSTY WINDS
(35-40 KT) ALL THE WAY TO THE SFC. ALTHOUGH WE FEEL THIS IS A LOW
PROB OCCURRENCE...KSYR AND KBGM MAY BE THE MOST PROBABLE SITES FOR
THIS (DOWNSLOPING SRLY FLOW AT KSYR AND ADDED ELEVATION AT KBGM).
SUCH TRENDS WILL OBVIOUSLY BE WATCHED CLOSELY THROUGHOUT THE DAY.
EARLY THIS MRNG...SOME LWR CLDS AND LGT FOG COULD OCNLY FLOAT
THROUGH AT KBGM/KAVP. OTHERWISE...MAINLY VFR SHOULD PREVAIL INTO
EARLY AFTN.
FROM 19-22Z ONWARD THROUGH THE EVE HRS...AS THE MAIN COLD FRNTL BNDRY
SLOWLY APPROACHES...RAIN SHOULD BECOME STEADIER IN NATURE...WITH
PREVAILING MVFR CONDS. EMBEDDED CONVECTIVE ELEMENTS ARE CERTAINLY
NOT OUT OF THE QUESTION...GIVEN THE STRENGTH OF THIS SYSTEM...AND
THE UNSEASONABLE WARMTH IN PLACE. HOWEVER...WE DON`T FEEL
CONFIDENT ENOUGH TO INSERT THUNDER OR EXCESSIVE WIND GUSTS (40+
KT) ATTM. ONCE AGN...RADAR TRENDS WILL BE CLOSELY MONITORED
THROUGHOUT THE DAY.
FROPA SHOULD OCCUR FM 06-09Z THU...WITH AN ABRUPT WIND SHIFT TO
WRLY...AND QUITE AN INCREASE IN THE WINDS AS WELL (GUSTS OF 35-45 KT).
.OUTLOOK...
THU/FRI/SAT/SUN...OCNL MVFR TO IFR RESTRICTIONS...IN SHSN.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS 1 TO UP TO 2.5
INCHES WITH THE HEAVIEST RAIN AXIS FURTHER WEST ACROSS THE FINGER
LAKES AND CHEMUNG BASINS OF NY. WILL HAVE TWO BATCHES WITH THE
INITIAL BATCH ALREADY IN WRN PA AND WRN NY NOW. THIS FIRST BATCH
MOVES QUICKLY THROUGH THIS AFTN. RAINFALL THIS AFTN UP TO HALF AN
INCH. QUICK RESPONSE ON STREAMS BUT NO FLOODING INITIALLY. THE
COLD FRONT WILL COME THROUGH LATE EVE AND EARLY MORNING WITH MORE
HEAVY RAIN. ANOTHER QUICK INCH IN LESS THAN 6 HOURS WHICH WILL BE
MOSTLY RUNOFF. STREAMS AND RIVERS WILL RESPOND QUICKLY. FLASH
FLOODING POSSIBLE...FOLLOWED BY MINOR RIVER FLOODING.
FLOOD WATCH CONTINUES FOR ENTIRE CWA STARTING AT 4 PM INTO
THURSDAY MORNING. RIVER FLOOD WARNINGS JUST ISSUED FOR
WEST BRANCH DELAWARE RIVER AT WALTON
TIOUGHNIOGA RIVER AT CORTLAND
CHENANGO RIVER AT SHERBURNE
SUSQUEHANNA RIVER AT VESTAL
SUSQUEHANNA RIVER AT WAVERLY/SAYRE
SUSQUEHANNA RIVER AT TOWANDA
SUSQUEHANNA RIVER AT MESHOPPEN
SUSQUEHANNA RIVER NEAR WILKES-BARRE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...PVN
SHORT TERM...
LONG TERM...PVN
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
858 AM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
9 AM UPDATE...
YET ANOTHER UPDATE TO BUMP TEMPS DOWN AT KAVP WITH SENSOR READING
AROUND 4 DEGREES TOO WARM. NO OTHER CHGS NEEDED AT THIS TIME AS A
MAJOR WX EVENT IS IMPENDING FOR TONIGHT.
730 AM UPDATE...
QUICK UPDATE TO BUMP CURRENT TEMPS UP IN WYOMING/LACKAWANNA VLYS
AS KAVP IS NOW UP TO 62F. MESONET SITES IN THAT AREA ARE CURRENTLY
IN THE MID-50S THUS NOT OUT OF THE QUESTION THAT SCRANTON WILKES-
BARRE AIRPORT IS IN THE LOW 60S AS IT SITS AROUND 1000 FEET UP AND
WITH STRONG INVERSION IN PLACE PER KALY/KOKX 12Z RAOBS.
630 AM UPDATE...MINOR T/TD TWEEKS IN THE NEAR TERM...RAISING MAXES
BY A FEW DEG MAINLY FINGER LAKES AND CNTRL SRN TIER. ALSO ADDED
PC SKIES FOR PARTS OF THE RGN THIS MRNG. CRUDE XTRAPOLATION OF
LEADING PCPN SHIELD INDICATES ARRIVAL TIME ARND 1730Z INTO WRN STEUBEN.
WE`LL SEE IF THIS HOLDS. NO OTHER CHGS. PREV BLO...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCURRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FIELD YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALLOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LK EFFECT SNOW STARTING OFF PD ACRS FAR NRN NY WL TRANSITION NORTH
OF THE REGION BY 06Z SATURDAY AS SFC RIDGE NOSES INTO AREA. WK UL
TROF WL MV THRU SAT AFTN WITH EC BEING STRONGEST WITH VORT MAX AND
GFS WEAKER. THEREFORE HV GONE WITH ONLY CHC POPS AT THIS TIME PER HPC
GUIDANCE. POPS WL INCREASE SAT NGT AND SUN AS ANOTHER WV AND ASSOC
SFC LOW DROPS THRU THE CWA THO ONLY TO BTWN 40-50%.
12Z GUIDANCE HAS COME INTO BETTER AGREEMENT WITH WV DROPPING INTO
NERN U.S. AND DVLPNG SFC LOPRES SUN AFTN/EVNG SOMEWHERE IN THE GULF
OF MAINE. ENERGY WL LKLY NOT TRANSFER OFF THE COAST QUICKLY ENUF TO
GIVE US A THREAT FOR WIDESPREAD SNOW FOR EARLY NEXT WEEK.
TEMPS DRG THE EXTNDD PORTION WL SETTLE OUT CLOSE TO SEASONAL VALUES.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
12Z WED UPDATE... ONE OF THE MAIN AVIATION IMPACTS THE NEXT 12-18
HRS WILL BE LLWS...AS A VERY STG LOW-LVL JET DVLPS OVER THE
RGN...WITH AN INVERSION ALSO IN PLACE IN THE LWST 2K FT...TO KEEP
THE STGST WINDS JUST OFF THE SFC. THIS HAZARD WAS CARRIED AT ALL
SITES. THERE IS SOME PSBLTY THAT WARMING SFC TEMPS THIS AFTN WILL
BE ENOUGH TO ERODE THE INVERSION...AND BRING STG GUSTY WINDS
(35-40 KT) ALL THE WAY TO THE SFC. ALTHOUGH WE FEEL THIS IS A LOW
PROB OCCURRENCE...KSYR AND KBGM MAY BE THE MOST PROBABLE SITES FOR
THIS (DOWNSLOPING SRLY FLOW AT KSYR AND ADDED ELEVATION AT KBGM).
SUCH TRENDS WILL OBVIOUSLY BE WATCHED CLOSELY THROUGHOUT THE DAY.
EARLY THIS MRNG...SOME LWR CLDS AND LGT FOG COULD OCNLY FLOAT
THROUGH AT KBGM/KAVP. OTHERWISE...MAINLY VFR SHOULD PREVAIL INTO
EARLY AFTN.
FROM 19-22Z ONWARD THROUGH THE EVE HRS...AS THE MAIN COLD FRNTL BNDRY
SLOWLY APPROACHES...RAIN SHOULD BECOME STEADIER IN NATURE...WITH
PREVAILING MVFR CONDS. EMBEDDED CONVECTIVE ELEMENTS ARE CERTAINLY
NOT OUT OF THE QUESTION...GIVEN THE STRENGTH OF THIS SYSTEM...AND
THE UNSEASONABLE WARMTH IN PLACE. HOWEVER...WE DON`T FEEL
CONFIDENT ENOUGH TO INSERT THUNDER OR EXCESSIVE WIND GUSTS (40+
KT) ATTM. ONCE AGN...RADAR TRENDS WILL BE CLOSELY MONITORED
THROUGHOUT THE DAY.
FROPA SHOULD OCCUR FM 06-09Z THU...WITH AN ABRUPT WIND SHIFT TO
WRLY...AND QUITE AN INCREASE IN THE WINDS AS WELL (GUSTS OF 35-45 KT).
.OUTLOOK...
THU/FRI/SAT/SUN...OCNL MVFR TO IFR RESTRICTIONS...IN SHSN.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS UP TO 2 INCHES OF
QPF OVER THE WRN CATS AND PARTS OF NEPA. THIS SEEMS RATHER HIGH
FOR A FAST MVG COLD FNT BUT WE DO HAVE A WV DVLPG ALONG THE FNT
THAT DVLPS GOOD LL CONV THAT IN TURN BRINGS A PD OF SLY OR SELY
INFLOW...MAINLY INTO THE CATS. IF WE SEE THE WORST CASE SCENARIO
THERE WLD BE SOME MINOR FLOOD PRBLMS ON THE MAIN RVRS. OF BIGGER
CNCRN TO ME WLD BE THE SMALLER STREAMS WHERE THIS PTNL RAIN WLD
FALL OVER A RELATIVELY SMALL WINDOW...ABT 6 HRS. OTR FACTOR TO
ALWAYS CONSIDER IS THE ONGOING PRBLM WITH FLOOD DAMAGED STREAM BEDS
IN THE AREA FROM PAST EVENTS. WILL ISSUE A GENERIC FLOOD WATCH FOR
THE WESTERN CATS AND MUCH OF NEPA TO CVR THE RAIN AND FLOOD PTNL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...PVN
SHORT TERM...
LONG TERM...PVN
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
738 AM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
730 AM UPDATE...
QUICK UPDATE TO BUMP CURRENT TEMPS UP IN WYOMING/LACKAWANNA VLYS
AS KAVP IS NOW UP TO 62F. MESONET SITES IN THAT AREA ARE CURRENTLY
IN THE MID-50S THUS NOT OUT OF THE QUESTION THAT SCRANTON WILKES-
BARRE AIRPORT IS IN THE LOW 60S AS IT SITS AROUND 1000 FEET UP AND
WITH STRONG INVERSION IN PLACE PER KALY/KOKX 12Z RAOBS.
630 AM UPDATE...MINOR T/TD TWEEKS IN THE NEAR TERM...RAISING MAXES
BY A FEW DEG MAINLY FINGER LAKES AND CNTRL SRN TIER. ALSO ADDED
PC SKIES FOR PARTS OF THE RGN THIS MRNG. CRUDE XTRAPOLATION OF
LEADING PCPN SHIELD INDICATES ARRIVAL TIME ARND 1730Z INTO WRN STEUBEN.
WE`LL SEE IF THIS HOLDS. NO OTHER CHGS. PREV BLO...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCURRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FIELD YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALLOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LK EFFECT SNOW STARTING OFF PD ACRS FAR NRN NY WL TRANSITION NORTH
OF THE REGION BY 06Z SATURDAY AS SFC RIDGE NOSES INTO AREA. WK UL
TROF WL MV THRU SAT AFTN WITH EC BEING STRONGEST WITH VORT MAX AND
GFS WEAKER. THEREFORE HV GONE WITH ONLY CHC POPS AT THIS TIME PER HPC
GUIDANCE. POPS WL INCREASE SAT NGT AND SUN AS ANOTHER WV AND ASSOC
SFC LOW DROPS THRU THE CWA THO ONLY TO BTWN 40-50%.
12Z GUIDANCE HAS COME INTO BETTER AGREEMENT WITH WV DROPPING INTO
NERN U.S. AND DVLPNG SFC LOPRES SUN AFTN/EVNG SOMEWHERE IN THE GULF
OF MAINE. ENERGY WL LKLY NOT TRANSFER OFF THE COAST QUICKLY ENUF TO
GIVE US A THREAT FOR WIDESPREAD SNOW FOR EARLY NEXT WEEK.
TEMPS DRG THE EXTNDD PORTION WL SETTLE OUT CLOSE TO SEASONAL VALUES.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
12Z WED UPDATE... ONE OF THE MAIN AVIATION IMPACTS THE NEXT 12-18
HRS WILL BE LLWS...AS A VERY STG LOW-LVL JET DVLPS OVER THE
RGN...WITH AN INVERSION ALSO IN PLACE IN THE LWST 2K FT...TO KEEP
THE STGST WINDS JUST OFF THE SFC. THIS HAZARD WAS CARRIED AT ALL
SITES. THERE IS SOME PSBLTY THAT WARMING SFC TEMPS THIS AFTN WILL
BE ENOUGH TO ERODE THE INVERSION...AND BRING STG GUSTY WINDS
(35-40 KT) ALL THE WAY TO THE SFC. ALTHOUGH WE FEEL THIS IS A LOW
PROB OCCURRENCE...KSYR AND KBGM MAY BE THE MOST PROBABLE SITES FOR
THIS (DOWNSLOPING SRLY FLOW AT KSYR AND ADDED ELEVATION AT KBGM).
SUCH TRENDS WILL OBVIOUSLY BE WATCHED CLOSELY THROUGHOUT THE DAY.
EARLY THIS MRNG...SOME LWR CLDS AND LGT FOG COULD OCNLY FLOAT
THROUGH AT KBGM/KAVP. OTHERWISE...MAINLY VFR SHOULD PREVAIL INTO
EARLY AFTN.
FROM 19-22Z ONWARD THROUGH THE EVE HRS...AS THE MAIN COLD FRNTL BNDRY
SLOWLY APPROACHES...RAIN SHOULD BECOME STEADIER IN NATURE...WITH
PREVAILING MVFR CONDS. EMBEDDED CONVECTIVE ELEMENTS ARE CERTAINLY
NOT OUT OF THE QUESTION...GIVEN THE STRENGTH OF THIS SYSTEM...AND
THE UNSEASONABLE WARMTH IN PLACE. HOWEVER...WE DON`T FEEL
CONFIDENT ENOUGH TO INSERT THUNDER OR EXCESSIVE WIND GUSTS (40+
KT) ATTM. ONCE AGN...RADAR TRENDS WILL BE CLOSELY MONITORED
THROUGHOUT THE DAY.
FROPA SHOULD OCCUR FM 06-09Z THU...WITH AN ABRUPT WIND SHIFT TO
WRLY...AND QUITE AN INCREASE IN THE WINDS AS WELL (GUSTS OF 35-45 KT).
.OUTLOOK...
THU/FRI/SAT/SUN...OCNL MVFR TO IFR RESTRICTIONS...IN SHSN.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS UP TO 2 INCHES OF
QPF OVER THE WRN CATS AND PARTS OF NEPA. THIS SEEMS RATHER HIGH
FOR A FAST MVG COLD FNT BUT WE DO HAVE A WV DVLPG ALONG THE FNT
THAT DVLPS GOOD LL CONV THAT IN TURN BRINGS A PD OF SLY OR SELY
INFLOW...MAINLY INTO THE CATS. IF WE SEE THE WORST CASE SCENARIO
THERE WLD BE SOME MINOR FLOOD PRBLMS ON THE MAIN RVRS. OF BIGGER
CNCRN TO ME WLD BE THE SMALLER STREAMS WHERE THIS PTNL RAIN WLD
FALL OVER A RELATIVELY SMALL WINDOW...ABT 6 HRS. OTR FACTOR TO
ALWAYS CONSIDER IS THE ONGOING PRBLM WITH FLOOD DAMAGED STREAM BEDS
IN THE AREA FROM PAST EVENTS. WILL ISSUE A GENERIC FLOOD WATCH FOR
THE WESTERN CATS AND MUCH OF NEPA TO CVR THE RAIN AND FLOOD PTNL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
HIGH WIND WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...PVN
SHORT TERM...
LONG TERM...PVN
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
650 AM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...MINOR T/TD TWEEKS IN THE NEAR TERM...RAISING MAXES
BY A FEW DEG MAINLY FINGER LAKES AND CNTRL SRN TIER. ALSO ADDED
PC SKIES FOR PARTS OF THE RGN THIS MRNG. CRUDE XTRAPOLATION OF
LEADING PCPN SHIELD INDICATES ARRIVAL TIME ARND 1730Z INTO WRN STEUBEN.
WE`LL SEE IF THIS HOLDS. NO OTHER CHGS. PREV BLO...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCURRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FIELD YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALLOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LK EFFECT SNOW STARTING OFF PD ACRS FAR NRN NY WL TRANSITION NORTH
OF THE REGION BY 06Z SATURDAY AS SFC RIDGE NOSES INTO AREA. WK UL
TROF WL MV THRU SAT AFTN WITH EC BEING STRONGEST WITH VORT MAX AND
GFS WEAKER. THEREFORE HV GONE WITH ONLY CHC POPS AT THIS TIME PER HPC
GUIDANCE. POPS WL INCREASE SAT NGT AND SUN AS ANOTHER WV AND ASSOC
SFC LOW DROPS THRU THE CWA THO ONLY TO BTWN 40-50%.
12Z GUIDANCE HAS COME INTO BETTER AGREEMENT WITH WV DROPPING INTO
NERN U.S. AND DVLPNG SFC LOPRES SUN AFTN/EVNG SOMEWHERE IN THE GULF
OF MAINE. ENERGY WL LKLY NOT TRANSFER OFF THE COAST QUICKLY ENUF TO
GIVE US A THREAT FOR WIDESPREAD SNOW FOR EARLY NEXT WEEK.
TEMPS DRG THE EXTNDD PORTION WL SETTLE OUT CLOSE TO SEASONAL VALUES.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
12Z WED UPDATE... ONE OF THE MAIN AVIATION IMPACTS THE NEXT 12-18
HRS WILL BE LLWS...AS A VERY STG LOW-LVL JET DVLPS OVER THE
RGN...WITH AN INVERSION ALSO IN PLACE IN THE LWST 2K FT...TO KEEP
THE STGST WINDS JUST OFF THE SFC. THIS HAZARD WAS CARRIED AT ALL
SITES. THERE IS SOME PSBLTY THAT WARMING SFC TEMPS THIS AFTN WILL
BE ENOUGH TO ERODE THE INVERSION...AND BRING STG GUSTY WINDS
(35-40 KT) ALL THE WAY TO THE SFC. ALTHOUGH WE FEEL THIS IS A LOW
PROB OCCURRENCE...KSYR AND KBGM MAY BE THE MOST PROBABLE SITES FOR
THIS (DOWNSLOPING SRLY FLOW AT KSYR AND ADDED ELEVATION AT KBGM).
SUCH TRENDS WILL OBVIOUSLY BE WATCHED CLOSELY THROUGHOUT THE DAY.
EARLY THIS MRNG...SOME LWR CLDS AND LGT FOG COULD OCNLY FLOAT
THROUGH AT KBGM/KAVP. OTHERWISE...MAINLY VFR SHOULD PREVAIL INTO
EARLY AFTN.
FROM 19-22Z ONWARD THROUGH THE EVE HRS...AS THE MAIN COLD FRNTL BNDRY
SLOWLY APPROACHES...RAIN SHOULD BECOME STEADIER IN NATURE...WITH
PREVAILING MVFR CONDS. EMBEDDED CONVECTIVE ELEMENTS ARE CERTAINLY
NOT OUT OF THE QUESTION...GIVEN THE STRENGTH OF THIS SYSTEM...AND
THE UNSEASONABLE WARMTH IN PLACE. HOWEVER...WE DON`T FEEL
CONFIDENT ENOUGH TO INSERT THUNDER OR EXCESSIVE WIND GUSTS (40+
KT) ATTM. ONCE AGN...RADAR TRENDS WILL BE CLOSELY MONITORED
THROUGHOUT THE DAY.
FROPA SHOULD OCCUR FM 06-09Z THU...WITH AN ABRUPT WIND SHIFT TO
WRLY...AND QUITE AN INCREASE IN THE WINDS AS WELL (GUSTS OF 35-45 KT).
.OUTLOOK...
THU/FRI/SAT/SUN...OCNL MVFR TO IFR RESTRICTIONS...IN SHSN.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS UP TO 2 INCHES OF
QPF OVER THE WRN CATS AND PARTS OF NEPA. THIS SEEMS RATHER HIGH
FOR A FAST MVG COLD FNT BUT WE DO HAVE A WV DVLPG ALONG THE FNT
THAT DVLPS GOOD LL CONV THAT IN TURN BRINGS A PD OF SLY OR SELY
INFLOW...MAINLY INTO THE CATS. IF WE SEE THE WORST CASE SCENARIO
THERE WLD BE SOME MINOR FLOOD PRBLMS ON THE MAIN RVRS. OF BIGGER
CNCRN TO ME WLD BE THE SMALLER STREAMS WHERE THIS PTNL RAIN WLD
FALL OVER A RELATIVELY SMALL WINDOW...ABT 6 HRS. OTR FACTOR TO
ALWAYS CONSIDER IS THE ONGOING PRBLM WITH FLOOD DAMAGED STREAM BEDS
IN THE AREA FROM PAST EVENTS. WILL ISSUE A GENERIC FLOOD WATCH FOR
THE WESTERN CATS AND MUCH OF NEPA TO CVR THE RAIN AND FLOOD PTNL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
HIGH WIND WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
HIGH WIND WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
NYZ009-015>018-022>025-036-037-044>046-055>057-062.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...PVN
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
512 AM EST WED JAN 30 2013
.SYNOPSIS...
UNSEASONABLY WARM AIR WILL OVERSPREAD THE REGION TODAY IN ADVANCE
OF A STRONG COLD FRONT. SHOWERS AND SCATTERED THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON IN THIS MOIST AIR MASS...AND THE RAIN WILL
BE HEAVY AT TIMES. COLDER AIR BEHIND THE FRONT WILL TRIGGER LAKE
EFFECT SNOWS ACROSS CENTRAL NEW YORK ON THURSDAY AND THURSDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
510 AM UPDATE...BUMPED UP START TIME OF THE FLOOD WATCH TO 21Z.
PREV BLO..
LOTS TO LOOK AT THIS FCST PCKG. MAIN FOCUS IS ON THE APRCHNG
CDFNT AND DIGGING UPR TROF...WHICH WILL BRING A ROUND OF +RA AND
WIND TO THE RGN STARTING THIS AFTERNOON INTO THE OVRNGT HRS.
THERE IS TREMENDOUS BUST POTNL WITH THIS FCST...STARTING OFF WITH
MAX TEMPS TDA. WE ARE FCSTNG MAXES INTO THE LOWER 60S MAINLY W OF
I-81...BUT IF WE GET SOME BREAKS OF SUN LATER THIS MRNG THIS FCST
WILL BE ON THE COOL SIDE. WE ALSO NOTE THAT TEMPS ARE CRNTLY (AS
OF 330 AM) A60 OVER MOST OF OH. ATTM WE PLAYED IT CLOSE TO THE
VEST...WITH EXPECTATION THAT ANY SUNSHINE WILL BE LIMITED. BUT IT
IS SOMETHING TO WATCH.
MDLS HAVE BEEN LEANING SLOWER WITH THIS DYNAMIC SYSTEM...AND OUR
FCST REFLECTS THIS. DO NOT XPCT MUCH PCPN BEFORE 18Z...WITH THE
HEAVIEST RAIN LIKELY TO FALL VERY LATE AFTN/EVNG. WE EXPANDED THE
FFA TO INCLUDE THE ENTIRE FCST AREA...MAIN THREAT BEING +RA AND
FLASH FLOODING...AS MDLS ARE SHIFTING THE HEAVY PCPN AXIS FURTHER
TO THE WEST. WE STARTED THE FLOOD WATCH AT 00Z EXPECTING THAT ANY
HYDRO ISSUES WILL BE AFTER THIS TIME...BUT DAY SHIFT MAY HAVE TO
MOVE UP THE START TIME IF PCPN WORKS IN EARLIER THAN XPCTD.
ATTM WE XPCT RAINFALL TO AVG SOMEWHERE BETWEEN 1 AND 2 INCHES....LCLY
HIER AMTS IN THE SRLY UPSLOPE FAVORED AREAS...LOWEST AMTS PRBLY IN
THE LAKE PLAIN. ADDED TSRA TO THE MIX THIS AFTN/EVNG GIVEN WHAT`S
BEEN OCCRRING UPSTREAM AND FCST SI`S FROM 0 TO -2. STRONG DYNAMICS
IN ALMOST ANY FLEID YOU LOOK AT...INCLUDING IMPRSV UPR LVL DVRGNC
ASSCD WITH THE RR QUAD OF AN UPR LVL JET COUPLED WITH STRONG LOW
LVL FNTL CONVERGENCE SO CAT POPS CONTINUE TO LOOK GOOD. STEADIER
RAINS WILL END LATER TNGT FROM W TO E...PSBLY MIXING WITH -SHSN
TWDS DAYBREAK.
POTNL FOR SOME VERY GUSTY WINDS WITH ANY CONVECTION THAT DVLPS
NEAR/ALONG THE FNT. GIVEN THIS AND THE STRONG WINDS XPCTD BEHIND
THE CDFNT ON THU...WE ISSUED A HIGH WIND WATCH FOR THE ENTIRE
RGN.
RECORD TEMPS FOR TDA INCLUDE 54F AT SYR (2006/1914), 52 AT BGM
(1974), AND 66 AT AVP (1947). SYR AND BGM RECORDS ARE GONERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
XPCT STRONG WINDS ON THU. NAM/GFS MOS GDNC SHOWING SUSTAINED 25
TO 30 WHICH IS ONE OF THE BETTER INDICATORS SUGGESTING WARNING
CRITERIA WINDS ALONG THE LAKE PLAIN. ISALOBARIC FIELDS ALSO MORE
IMPRSV THAN PREV WARNING/ADVISORY EVENT. POTNL FOR WARNING CRITERIA
SPCLY ACRS THE LAKE PLAIN AND PSBLY ADJACENT COUNTIES...WITH AN
ADVISORY APPEARING LIKELY FOR THE REMAINDER OF THE CWA.
AS COLDER AIR WORKS IN ON THU...LES WILL DVLP EAST OF LAKE
ONTARIO. PROFILES AND TRAJECTORIES LOOK FVRBL THU AFTN INTO THU
NGT FOR SIG ACCUMS AS 850 TEMPS FALL TO -18C...SO AN LES WATCH WAS
ISSUED. THIS ACTIVITY IS XPCTD TO DROP SWD LATE THU NGT ON 290-300
FLOW INTO ONON/MAD/SRN ONEIDA. THIS BAND MAY LIFT BACK NWD ON FRI
NGT AS LOW LVL FLOW BCMS SWLY AHEAD OF THE NXT CLIPPER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LK EFFECT SNOW STARTING OFF PD ACRS FAR NRN NY WL TRANSITION NORTH
OF THE REGION BY 06Z SATURDAY AS SFC RIDGE NOSES INTO AREA. WK UL
TROF WL MV THRU SAT AFTN WITH EC BEING STRONGEST WITH VORT MAX AND
GFS WEAKER. THEREFORE HV GONE WITH ONLY CHC POPS AT THIS TIME PER HPC
GUIDANCE. POPS WL INCREASE SAT NGT AND SUN AS ANOTHER WV AND ASSOC
SFC LOW DROPS THRU THE CWA THO ONLY TO BTWN 40-50%.
12Z GUIDANCE HAS COME INTO BETTER AGREEMENT WITH WV DROPPING INTO
NERN U.S. AND DVLPNG SFC LOPRES SUN AFTN/EVNG SOMEWHERE IN THE GULF
OF MAINE. ENERGY WL LKLY NOT TRANSFER OFF THE COAST QUICKLY ENUF TO
GIVE US A THREAT FOR WIDESPREAD SNOW FOR EARLY NEXT WEEK.
TEMPS DRG THE EXTNDD PORTION WL SETTLE OUT CLOSE TO SEASONAL VALUES.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
06Z WED UPDATE... THE PRIMARY AVIATION IMPACT THE NEXT 12-24 HRS
WILL LIKELY BE LLWS...AS A VERY STG LOW-LVL JET DVLPS OVER THE
RGN...WITH AN INVERSION ALSO IN PLACE IN THE LWST 2K FT...TO KEEP
THE STGST WINDS JUST OFF THE SFC. THIS HAZARD WAS CARRIED AT ALL SITES.
THERE IS SOME PSBLTY THAT WARMING SFC TEMPS THIS AFTN WILL BE
ENOUGH TO ERODE THE INVERSION...AND BRING STG GUSTY WINDS (35-40
KT) ALL THE WAY TO THE SFC. ALTHOUGH WE FEEL THIS IS A LOW PROB
OCCURRENCE...KSYR AND KBGM MAY BE THE MOST PROBABLE SITES FOR THIS
(DOWNSLOPING SRLY FLOW AT KSYR AND ADDED ELEVATION AT KBGM). SUCH
TRENDS WILL OBVIOUSLY BE WATCHED CLOSELY THROUGHOUT THE DAY.
EARLY THIS MRNG...LWR STRATUS CLDS AND FOG ARE EXPECTED TO PREVAIL
AT KELM/KBGM/KITH/KAVP...WITH PERSISTENT IFR. KSYR AND KRME SHOULD
STAY MVFR TO VFR. FROM ABT 14-21Z...LWR CLDS COULD WELL BREAK FOR
A TIME AT KELM/KSYR...WITH MOSTLY VFR. ELSEWHERE...BKN-OVC MVFR
CIGS ARE EXPECTED TO PREVAIL.
FROM ABT 21Z ONWARD THROUGH THE EVE HRS...AS THE MAIN COLD FRNTL
BNDRY SLOWLY APPROACHES...RAIN SHOULD BECOME STEADIER IN
NATURE...WITH PREVAILING MVFR CONDS. EMBEDDED CONVECTIVE ELEMENTS
ARE CERTAINLY NOT OUT OF THE QUESTION...GIVEN THE STRENGTH OF THIS
SYSTEM...AND THE UNSEASONABLE WARMTH IN PLACE. HOWEVER...WE DON`T
FEEL CONFIDENT ENOUGH TO INSERT THUNDER OR EXCESSIVE WIND GUSTS
(40+ KT) ATTM. ONCE AGN...RADAR TRENDS WILL BE CLOSELY MONITORED
THROUGHOUT THE DAY.
FOR MOST SITES...FROPA SHOULD OCCUR FM 06-09Z THU (JUST BEYOND THE
VALID TAF PD).
.OUTLOOK...
THU/FRI/SAT/SUN...OCNL MVFR TO IFR RESTRICTIONS...IN SHSN.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS UP TO 2 INCHES OF
QPF OVER THE WRN CATS AND PARTS OF NEPA. THIS SEEMS RATHER HIGH
FOR A FAST MVG COLD FNT BUT WE DO HAVE A WV DVLPG ALONG THE FNT
THAT DVLPS GOOD LL CONV THAT IN TURN BRINGS A PD OF SLY OR SELY
INFLOW...MAINLY INTO THE CATS. IF WE SEE THE WORST CASE SCENARIO
THERE WLD BE SOME MINOR FLOOD PRBLMS ON THE MAIN RVRS. OF BIGGER
CNCRN TO ME WLD BE THE SMALLER STREAMS WHERE THIS PTNL RAIN WLD
FALL OVER A RELATIVELY SMALL WINDOW...ABT 6 HRS. OTR FACTOR TO
ALWAYS CONSIDER IS THE ONGOING PRBLM WITH FLOOD DAMAGED STREAM BEDS
IN THE AREA FROM PAST EVENTS. WILL ISSUE A GENERIC FLOOD WATCH FOR
THE WESTERN CATS AND MUCH OF NEPA TO CVR THE RAIN AND FLOOD PTNL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR PAZ038>040-043-044-047-048-072.
HIGH WIND WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
PAZ038>040-043-044-047-048-072.
NY...FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
HIGH WIND WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
NYZ009-015>018-022>025-036-037-044>046-055>057-062.
LAKE EFFECT SNOW WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR NYZ009.
&&
$$
LONG TERM...PVN
AVIATION...MLJ/RRM
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
109 AM EST WED JAN 30 2013
.SYNOPSIS...
WARM TEMPERATURES WILL BE IN PLACE AHEAD OF A COLD FRONT THAT WILL
ARRIVE WEDNESDAY. STRONG STORMS ORGANIZED AHEAD OF THE FRONT WILL
AFFECT OUR AREA DURING THE EARLY TO MID MORNING HOURS WEDNESDAY.
BEHIND THIS SYSTEM...COLDER AIR WILL RETURN TO THE REGION FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MODELS KEEP OFFERING SUBTLE TIMING ISSUES FOR THE ARRIVAL OF A
PREFRONTAL TROUGH LATE TONIGHT INTO WEDNESDAY MORNING THAT WILL
MOSTLY LIKELY BE REALIZED AS A WELL DEFINED BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS. DID NOT WANT TO MESS WITH THE TIMING TOO
MUCH UNTIL WE CAN GET A MORE DEFINED TRACK TO OUR WEST AND WITH A
CHANCE TO LOOK AT THE FULL SUITE OF MODELS BOTH HIGH
RES/CONVECTIVE ALLOWING AND LOWER RES/CONVECTIVE PARAMETRIZATION.
IT APPEARS THAT THE LATEST 00Z NAM-WRF TRICKLING IN IS NOT
DEPICTING ANY MUCAPE WITH CURRENT CONVECTION TO OUR WEST/NORTHWEST
WHILE THE LATEST RAP AT LEAST SHOWS 200-400 J/KG. BY THE TIME THE
LINE ARRIVES LATE TONIGHT INTO WEDNESDAY...BEST ESTIMATE OF MUCAPE
SHOULD STILL BE IN THE 200-400 J/KG. EVEN IF THIS DOES NOT RESULT
IN MUCH LIGHTNING ACTIVITY...A VERY STRONG 925 MB TO 850 MB LOW
LEVEL JET WILL ACCOMPANY IT...AND IT CAN NOT BE TAKEN LIGHTLY. IT
WOULD NOT TAKE MUCH FOR CONVECTIVE DOWNDRAFTS TO BRING DOWN 50
KNOT WINDS TO THE SURFACE WHEN THEY ARE FORECAST TO BE IN THE
LOWER 50S KNOTS AROUND 1500 FEET. SO...CURRENT HWO HIGHLIGHTS
THIS. ANOTHER CONCERN WILL BE THE THREAT FOR HIGHER WIND GUSTS
BEFORE THE LINE OF ARRIVES SHOULD SOME STRAY SHOWER ACTIVITY
PRECEDE IT WHICH MAY BRING DOWN STRONGER WINDS DUE TO LIGHT
SPRINKLES OR VIRGA. WILL CONTINUE TO MONITOR THIS. TEMPERATURES
OVERNIGHT WILL REMAIN VERY WARM DUE TO INCREASING SOUTHERLY FLOW
AHEAD OF THE PREFRONTAL TROUGH AND SHOULD BOTTOM OUT IN THE UPPER
50S TO THE LOWER 60S BY SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
BEHIND THE LEADING EDGE OF THIS CONVECTIVE COMPLEX WILL BE AN AREA
OF MORE STRATIFORM PRECIPITATION AND LIGHTER WINDS THAT WILL LAST
INTO THE MID MORNING HOURS IN THE WEST...AND THE EARLY AFTERNOON
IN THE EAST. ALL THIS ACTIVITY WILL BE PRE-FRONTAL...THEREFORE A
MARKED TEMPERATURE DECREASE WILL NOT BE EXPECTED UNTIL LATER IN
THE AFTERNOON AS THE FRONT PASSES. SOME SHOWER ACTIVITY IS
EXPECTED AS THE FRONT PASSES WITH A WIND SHIFT OUT THE NORTHWEST.
WINDS WILL BECOME GUSTY FROM THE AFTERNOON INTO THE LATE EVENING
BEHIND THE FRONT. WITH THE LOW RAPIDLY DEPARTING...DO NOT EXPECT
WINDS TO GUST MUCH OVER 40 MPH BEHIND THE FRONT. CAA SNOW SHOWERS
WILL BE POSSIBLE DURING THE EVENING BEHIND THE FRONT...BEFORE THE
ORIENTATION OF THE FLOW BECOMES MORE WESTERLY...ENDING ANY SNOW
SHOWERS LATE WEDNESDAY NIGHT.
BREEZY CONDITIONS WILL CONTINUE THURSDAY AS HIGH PRESSURE TRIES TO
BUILD SOUTHEASTWARD ACROSS THE PLAINS. A WEAK DISTURBANCE RIDING
UNDERNEATH THE BASE OF A DEEP TROUGH CENTERED OVER EASTERN CANADA
WILL PASS ACROSS OUR AREA THURSDAY NIGHT. MODELS VARY A BIT IN
THEIR STRENGTH OF THIS FEATURE AND IN THE MOISTURE AVAILABLE FOR IT
TO WORK WITH. CURRENT INDICATIONS ARE THAT SOME OF OUR FORECAST
AREA...PARTICULARLY THE SOUTH...MAY SEE SOME SNOW OVERNIGHT
THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A SHORTWAVE WILL BE DEPARTING THE GREAT LAKES REGION ON
FRIDAY...WITH CLOUDS REMAINING OVER THE UPPER OHIO VALLEY TO START
THE PERIOD. IT APPEARS THAT THE SNOW WILL BE LIMITED TO AREAS
NORTHEAST OF THE ILN CWA BY FRIDAY...SO NO POPS HAVE BEEN INCLUDED
IN THE FORECAST.
THE AIR MASS ON FRIDAY WILL BE VERY COLD...WITH 850MB TEMPERATURES
OVER THE CWA RANGING FROM -16 TO -20 DEGREES CELSIUS. STANDARDIZED
ANOMALIES INDICATE THESE TEMPERATURES APPROACH 2 STANDARD DEVIATIONS
BELOW NORMAL...NOT AS SIGNIFICANT AS THE ARCTIC AIR LAST WEEK...BUT
STILL RATHER COLD. MAX TEMPS ON FRIDAY HAVE BEEN LOWERED
SLIGHTLY...THOUGH NOT AS COLD AS THE RAW GFS.
THROUGH THE REST OF THE PERIOD...OVERALL MODEL AGREEMENT IN THE
LARGE-SCALE PATTERN IS GOOD THROUGH MONDAY. ON MONDAY AND
LATER...GFSE SPREADS BECOME FAIRLY LARGE...WITH LESS CERTAINTY IN
THE STRENGTH AND TIMING OF THE NEXT WEATHER SYSTEMS TO IMPACT THE
REGION.
ON SATURDAY...A WEAK NORTHWEST FLOW SYSTEM WILL MOVE THROUGH THE
REGION. WITH SOME INCREASING CONFIDENCE IN THE TIMING OF THIS
SYSTEM...POPS WERE INCREASED WELL INTO THE CHANCE CATEGORY FOR THE
WHOLE CWA. VERIFYING AS CURRENTLY DEPICTED IN THE MODELS...THIS
SYSTEM COULD PRODUCE AN INCH OR TWO OF SNOW.
TEMPERATURES WILL GRADUALLY MODERATE OVER THE NEXT FEW DAYS...AS
SURFACE HIGH PRESSURE BUILDS IN BEHIND THE SATURDAY SYSTEM. THE
TEMPERATURE FORECAST HAS BEEN INCREASED SLIGHTLY THROUGH MONDAY.
A COLD FRONT IS FORECAST TO MOVE THROUGH THE CWA ON MONDAY NIGHT.
WHILE THE GFS/ECMWF ARE IN DECENT AGREEMENT ON TIMING...THE STRENGTH
OF THE FRONT AND AMOUNT OF MOISTURE AVAILABLE REMAIN UNCERTAIN.
TEMPERATURES WITH THIS FRONT WILL LIKELY SUPPORT A MIX OF RAIN OR
SNOW...WITH NOTHING INDICATING ICY PRECIPITATION AT THIS TIME.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
DYNAMIC WX SYSTEM WILL AFFECT THE REGION TODAY. LINE OF CONVECTION
ASSOCIATED WITH A PRE FRONTAL TROF IS OVER WRN INDIANA ATTM. HAVE
THIS TIMED TO THE WRN TAFS AROUND 10Z. CIGS AND VSBYS WILL DROP TO
AT LEAST MVFR WITH THE LINE. LIGHTNING WITH THE LINE HAS BEEN
WAINING OVER THE LAST COUPLE OF HOURS...SO CONTINUED WITH ONLY A
VCTS ATTM. WINDS ALOFT WITH THIS SYSTEM ARE OVER 50 KTS. QUESTION
IS WHETHER THESE WINDS WILL BE REALIZED AT THE TAF SITES. DECIDED
TO GO WITH GUSTS TO 40 KTS ATTM. HAVE THE CONVECTION TIMED E OF
CMH BY 13-15Z.
DIRECTLY BEHIND THE CONVECTION...WINDS SHOULD TURN TO THE NW
ALONG WITH MVFR CIGS AND VSBYS IN LINGERING SHRA FOR A FEW HOURS.
WINDS WILL GRADUALLY TURN BACK TO THE NW AHEAD OF THE MAIN CDFNT
BY LATE MORNING IN THE W AND EARLY AFTN IN THE E.
STRONG CDFNT REACHES THE WRN TAFS AROUND 00Z. THE CAA BEHIND THE
FNT WILL PULL DOWN STRONG AIR ALOFT. EXPECT GUSTS AGAIN OVER 35
KTS POST FRONTAL. ALONG WITH THE STRONG WINDS CIGS WILL DROP BACK
TO MVFR AND THERE WILL BE A CHANCE OF SHRA.
OUTLOOK...BREEZY TO WINDY CONDITIONS TO CONTINUE WEDNESDAY NIGHT
INTO THURSDAY. MVFR CEILINGS TO CONTINUE THURSDAY INTO THURSDAY
NIGHT WITH MVFR VSBYS POSSIBLE THURSDAY NIGHT. MVFR CONDITIONS
POSSIBLE AGAIN SATURDAY INTO SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN/LATTO
NEAR TERM...HICKMAN/LATTO
SHORT TERM...LATTO
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1150 PM CST TUE JAN 29 2013
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...06Z AVIATION DISCUSSION.
STILL GENERALLY BELIEVE THAT MAIN IMPACTS FROM A LINE OF STORMS MOVING
THRU WRN TN AT THIS TIME WILL BEGIN IMPACTING CKV AROUND 30/07Z...BNA
30/08Z...AND CSV 30/11Z. SOME BRIEF HEAVY RAINFALL POTENTIAL WILL ALSO
ACCOMPANY THE STRONGER STORMS...WITH SFC GUSTS TO 45KTS POSSIBLE IF NOT
HIGHER...WITH ISO SVR TSTMS CERTAINLY NOT OUT OF THE QUESTION. STILL
TIMING AND DURATION UNCERTAINTIES ABOUND...HOWEVER CKV/BNA CAN EXPECT
THE STRONGEST STORMS TO MOVE OUT OF VCNTY 30/11-30/12Z. CSV MAY CONTINUE
TO EXPERIENCE STRONGEST STORMS UNTIL AROUND 30/15Z. WINDS ARE STILL EXPECTED
TO REMAIN AROUND 20 KTS WITH GUSTS TO 30 KTS FOR AREA THRU 30/24Z. CHANGE
OVER TO ALL SHWRS IS EXPECTED W TO E DURING 30/18Z-31/00Z TOO. SOME WRAP
AROUND MOISTURE POSSIBLE...ALONG WITH WEAK INSTABILITY ASSOCIATED WITH
UPPER LEVEL TROUGH PASSAGE...TO SUPPORT A RAIN/SNOW MIX CSV FROM 31/02Z-31/06Z.
&&
.PREV DISCUSSION.../ISSUED 839 PM CST TUE JAN 29 2013/
UPDATE...
VWP CONTINUING TO SHOW A GRADUAL INCREASE IN
WIND SPEEDS...PARTICULARLY SEVERAL THOUSAND FEET ABOVE GROUND.
MODELS STILL INDICATING SOME LOWER LEVEL SUBSIDENCE OUT AHEAD OF
THE CONVECTION TO OUR WEST. LATEST TN STATE ROUNDUP SHOWING SOME
30 TO 35 MPH GUSTS ACROSS WESTERN TN. THESE HIGHER SPEEDS WILL
CONTINUE TO MOVE OUR WAY OVERNIGHT.
CONVECTION WISE...TWO MAIN AREAS OF PRE FRONTAL FORCING INDICATED
ACROSS CENTRAL AND EASTERN AR NOW. ITS LOOKING AS THOUGH THE
LEADING LINE WILL REACH THE MS RIVER AROUND 04Z OR 05Z. THERE IS A
LEADING AREA OF CONVECTION ACROSS NRN MS BUT IT APPEARS TO BE
OUTRUNNING THE BETTER INSTABILITY AT THIS TIME.
LATEST HRRR DATA SHOWS THE MAIN LINE OF STORMS REACHING THE TN
RIVER AROUND 08Z. LATEST NAM DATA STILL SHOWING A GOOD DEAL OF
INSTABILITY WITH NEG SHOWALTER VALUES TRAVERSING THE AREA.
FURTHERMORE...HELICITY VALUES REMAIN QUITE HIGH. THUS...THE
TORNADO WATCHES TO OUR WEST ARE LIKELY TO PROPAGATE EASTWARD
OVERNIGHT. NAM CONTINUES TO RUN A FEW HOURS TOO SLOW WITH THE
EXPECTED CONVECTION. NEAR 60 DEW POINTS NOW COVER THE BULK OF OUR
AREA...WITH SOME LOWER TO MID 60S DEWPOINTS ACROSS SOUTHERN MIDDLE
TN.
NO ADDITIONAL UPDATES TO THE ZONES ARE NEEDED FOR NOW. THERE COULD
STILL BE SOME PRE MIDNIGHT CONVECTION...BUT THE BULK OF THE
ACTIVITY WILL BE AFTER MIDNIGHT. UPDATES TO COMMENCE WITH THE
LIKELY INTRODUCTION OF CONVECTIVE WATCH BOXES LATER TONIGHT.
PREV DISCUSSION... /ISSUED 614 PM CST TUE JAN 29 2013/
UPDATE...00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
SFC PRESSURE GRADIENT WILL CONTINUE TO INCREASE AS APPROACHING COLD FRONTS
MOVE INTO/ACROSS MID STATE DURING 30/12Z-30/24Z. ALSO...STRONG LOW LEVEL
WIND SHEAR JUST OFF SFC WITH SLY WINDS 60KT-70KT EXPECTED THRU AROUND 30/12Z...
WITH SOME SFC GUSTS TO AROUND 45KT EVEN POSSIBLE ALONG LEADING EDGE. A LINE
OF STORMS...AT LEAST IN VCNTY OF COLD FRONTAL PASSAGE...AND MAY ALSO FORM
OUT AHEAD...AS MOISTURE...INSTABILITY...AND LIFTING MECHANISMS COME INTO
PLAY...AND THEN QUICKLY MOVE NEWD. EXPECT IMPACTS AT CKV AROUND 30/07Z...
BNA 30/08Z...AND CSV 30/11Z. SOME HEAVY RAINFALL WILL ALSO ACCOMPANY THE
STRONGER STORMS WITH SVR TSTMS POSSIBLY ALSO OUT AHEAD AND EMBEDDED IN
LINE. TIMING AND DURATION OF THE LINE OF STORMS IS STILL UNCERTAIN...HOWEVER
CKV/BNA CAN EXPECT THE STRONGEST STORMS TO MOVE OUT OF THE AREA BETWEEN
30/11-30/12Z. CSV MAY CONTINUE TO EXPERIENCE STRONGEST STORMS UNTIL AROUND
30/15Z. WINDS ARE STILL EXPECTED TO REMAIN AROUND 20 KTS WITH GUSTS TO 30 KTS
FOR AREA THRU 30/24Z. CHANGE OVER TO ALL SHWRS IS EXPECTED W TO E DURING THE
30/18Z-30/24Z TOO.
PREV DISCUSSION.../ISSUED 536 PM CST TUE JAN 29 2013/
UPDATE...
MAIN FRONTAL BOUNDARY EXTENDS FROM CENTRAL MO SW THROUGH EASTERN
OK. SEVERAL PRE FRONTAL BOUNDARIES IN ADVANCE OF THIS FEATURE WITH
THE MAIN LINE OF CONVECTION CURRENTLY OVER NW AR. INSTABILITY AXIS
WILL CONTINUE TO TRANSFER EASTWARD OVERNIGHT WITH THE MAIN LINE OF
STORMS REACHING FAR WESTERN TN BETWEEN 03Z AND 07Z. IN ADVANCE OF
THIS HOWEVER...CONVECTION STILL POSSIBLE AND WE ARE ALREADY SEEING
SOME SHOWER AND TSTM ACTIVITY INTO PORTIONS OF EASTERN AR.
GFS LOOKING A LITTLE FAST WITH THE MAIN LINE WHILE THE NAM MAY BE
A LITTLE SLOW. BUT...THE MODELS ARE IN AGREEMENT WITH A VERY
STRONG LINEAR OMEGA FIELD MATCHING UP WITH A POWERFUL 70-80 KT
850 MB JET. FURTHERMORE...SHOWALTERS AT OR JUST BELOW ZERO WILL
ALIGN WITH AN IMPRESSIVE LOW TO MID LEVEL THETA-E AXIS TO HELP
PROPEL THE CONVECTION.
IN ADDITION TO THE SEVERE WEATHER THREAT...THE PRESSURE GRADIENT
IS EXPECTED TO TIGHTEN UP BETWEEN NOW AND THROUGH 06Z. GOOD LOWER
LEVEL SUBSIDENCE IS INDICATED AS THE WINDS ALOFT BEGIN TO
STRENGTHEN. THUS...GUSTS TO 35 OR 40 MPH SHOULD BE EASY TO REACH
OVERNIGHT.
FOR THE UPDATE...WILL ATTEMPT TO ADJUST GRIDS SO AS TO INCREASE
THE WIND SPEEDS IN THE ZONE TEXT. REMAINDER OF FCST IS IN GOOD
SHAPE. THREAT OF STORMS DOES EXIST AHEAD OF THE MAIN LINE SO WILL
LEAVE THE DAMAGE POTENTIAL IN PRIOR TO MIDNIGHT FOR NOW. UPDATE
OUT SHORTLY.
PREV DISCUSSION... /ISSUED 349 PM CST TUE JAN 29 2013/
DISCUSSION...
THE FRONTAL PASSAGE AND ASSOCIATED SQUALL LINE WILL BE THE FOCUS OF
THE FORECAST.
LOW LEVEL WINDS ARE EXPECTED TO CONTINUE TO INCREASE
AHEAD OF THE APPROACHING SYSTEM. A WIND ADVISORY CONTINUES FOR AREAS
WEST OF THE PLATEAU UNTIL 6 PM WEDNESDAY...WHILE AREAS ALONG THE
PLATEAU ARE UNDER A WIND ADVISORY STARTING AT 6 PM TONIGHT AND
LASTING THROUGH 9 PM WEDNESDAY. SUSTAINED 25 MPH WINDS ARE
POSSIBLE WITH GUSTS TO 45 MPH.
PLENTY OF MOISTURE AND WARM AIR WILL CONTINUE TO SURGE INTO
MIDDLE TN AHEAD OF THE SYSTEM. A FEW ISOLATED SHOWERS MAY BE
POSSIBLE AHEAD OF THE LINE...BEFORE MIDNIGHT. HOWEVER THE MAIN
THREAT REMAINS WITHIN AND AROUND THE EXPECTED SQUALL LINE...WITH
THE MAIN CONCERNS BEING DAMAGING STRAIGHT LINE WINDS AND QLCS
TORNADOES. THE ETA OF THE MAIN ACTIVITY WILL BE 11 PM TO 2 AM FOR
AREAS NEAR THE TENNESSEE RIVER....1 AM TO 4 AM FOR AREAS ALONG THE
I-65 CORRIDOR AND 4 AM TO 9 AM FOR AREAS ALONG AND NEAR THE
CUMBERLAND PLATEAU. PWAT VALUES STILL REMAIN RELATIVELY HIGH FOR
THIS TIME OF YEAR, HOWEVER DUE TO THE RATHER QUICK MOVEMENT OF THE
STORM SYSTEM FLOODING DOES NOT APPEAR TO BE A MAJOR ISSUE. 1 TO
1.5 INCHES OF RAINFALL WILL BE POSSIBLE ACROSS THE AREA WITH
LOCALLY HIGHER AMOUNTS WITHIN THE STRONGEST CELLS. BECAUSE THE
GROUND WILL BE FAIRLY SATURATED EVEN SUB-SEVERE WIND GUSTS COULD
CAUSE TREES TO TOPPLE OVER.
THE MAIN LINE OF STORMS IS EXPECTED TO EXIT THE PLATEAU BY MID
MORNING ON WEDNESDAY. SOME SHOWERS MAY LINGER AROUND THE MID STATE
INTO THE AFTERNOON...AFTER THE DEPARTURE OF THE MAIN LINE OF
STORMS...BUT BY LATE AFTERNOON THE WINDS WILL BEGIN TO SHIFT FROM
SOUTHERLY TO WESTERLY...USHERING COLDER DRIER AIR INTO THE AREA FROM
THE WEST.
BY WEDNESDAY NIGHT PRECIPITATION WILL TAPER OFF WEST TO EAST...WITH
A RAIN SNOW MIX TRANSITIONING TO LIGHT SNOW SHOWERS OR FLURRIES OVER
THE PLATEAU AND HIGHER TERRAIN LATE. COLD AIR ADVECTION PEAKS WITH
850MB TEMPS DROPPING TO ABOUT -8C ON WEDNESDAY AS BROAD UPPER TROUGH
OVER THE CONUS PERSISTS. EXPECT MARGINAL WARMING ON THURSDAY BEFORE
A WEAK BUT QUICK MOVING SHORTWAVE ROTATES AROUND THE TROUGH THURSDAY
NIGHT BRINGING THE POSSIBILITY OF LIGHT SNOWFALL TO THE AREA. LACK OF
MOISTURE SHOULD KEEP ACCUMULATIONS DOWN...RANGING FROM A DUSTING TO
A HALF INCH OVER THE LOWER ELEVATIONS...TO AROUND AN INCH OVER
PORTIONS OF THE PLATEAU. THIS SYSTEM COULD STRENGTHEN OR WEAKEN WITH
SUBSEQUENT MODEL RUNS...SO EXPECT CHANGES AS THE FORECAST TIME DRAWS
NEAR. FOR FRIDAY...NORTHWESTERLY WINDS OF 5-10KTS ALONG WITH COLD
AIR ADVECTION DROPPING 925MB TEMPS TO -8C TO -12C SHOULD MAKE FOR AN
UNPLEASANT DAY. BUNDLE UP.
BY THE WEEKEND...THE UPPER TROUGH LIFTS SLIGHTLY ALLOWING FOR A BIT
OF WARMING...BUT ANOTHER WEAK SHORTWAVE ROTATES AROUND AND BRINGS
PRECIPITATION BACK TO THE MID-STATE. THE WARMING SHOULD BE ENOUGH TO
CHANGE EXPECTED PRECIP TO LIGHT RAIN SHOWERS...THOUGH A RAIN-SNOW
MIX IS EXPECTED OVER THE HIGHER TERRAIN. LONG-RANGE MODELS INDICATE
AN UPPER TROUGH WILL DEVELOP OVER THE CENTRAL STATES ALLOWING FOR A
SOUTHERLY FLOW TO BRING WARM AND MOIST AIR BACK TO THE MID-STATE. AT
THIS POINT ITS UNCERTAIN HOW MUCH WILL OCCUR...SO WILL LIMIT WEATHER
TO CHANCE OF RAIN SHOWERS...AND WILL MONITOR MODEL UPDATES FOR
THUNDERSTORM POTENTIAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 9 PM CST WEDNESDAY FOR TNZ011-032>034-065-
066-078>080.
WIND ADVISORY UNTIL 6 PM CST WEDNESDAY FOR TNZ005>010-022>031-
056>064-075-077-093>095.
&&
$$
31
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1146 PM EST TUE JAN 29 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING UNSEASONABLY WARM TEMPERATURES TO THE
AREA WEDNESDAY. A STRONG COLD FRONT WILL MOVE THROUGH THE REGION
LATE WEDNESDAY ACCOMPANIED BY SHOWERS WITH GUSTY WINDS AND HEAVY
RAIN. MUCH COLDER TEMPERATURES WILL RETURN FOR THE END OF THE WEEK
INTO THE WEEKEND AS HIGH PRESSURE MOVES SOUTHEAST FROM CANADA.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 955 PM EST TUESDAY...
STARTING TO SEE SOME LIGHT REFLECTIVITY IN THE SOUTHWEST
COUNTIES. EXPECT COVERAGE OF LIGHT RAIN TO EXPAND...ESPECIALLY
AFTER MIDNIGHT IN THE FAVORED EASTERN UPSLOPE AREAS. HAVE
INCREASED PROBABILITY OF PRECIPITATION ALONG THE SOUTHERN BLUE
RIDGE IN LINE WITH LATEST WRF AND RAP GUIDANCE.
BASED ON EXPECTED WINDS BY WEDNESDAY AFTERNOON...ESPECIALLY
LOOKING AT THE 850 MB WINDS APPROACHING 60-65 KNOTS AND SUSTAINED
WINDS ON THE DAN BUFKIT REACHING 20-25 MPH...HAVE EXPANDED THE
WIND ADVISORY FOR THE REST OF THE COUNTY WARNING AREA. ALSO
STRETCHED TIME OF HIGH WIND WARNING IN THE SOUTHWEST COUNTIES TO
START AT 09Z. EXPECTING IT WILL NOT TAKE AS LONG AS 6AM TO START
SEEING HIGH WINDS.
AS OF 300 PM EST TUESDAY...
ALL AREAS ARE EXPECTED TO BE CLOUDY BY EARLY WEDNESDAY MORNING.
LIGHT PRECIPITATION WILL DEVELOP BY MIDNIGHT...PRIMARILY ALONG THE
CREST OF THE BLUE RIDGE SOUTHWEST OF FLOYD VA INTO NW NC. AFTER
MIDNIGHT...THE FOCUS FOR THE BEST CHANCE OF RAIN WILL STILL BE
ALONG THE CREST OF THE BLUE RIDGE...HOWEVER...ALL PARTS OF THE
FORECAST AREA WILL HAVE AT LEAST A SLIGHT CHANCE.
AS WEDNESDAY PROGRESSES...PRECIPITATION CHANCES WILL PROGRESSIVELY
INCREASE AS THE FRONT APPROACHES...AND THEN CROSSES THE AREA DURING
THE AFTERNOON. TRENDS OF THE LATEST MODEL GUIDANCE ARE ABOUT THREE
HOURS SLOWER WITH THE TIMING OF THE PASSAGE. AS SUCH...HAVE ADJUSTED
OUR POP AND WEATHER GRIDS ACCORDINGLY. WHEN THE FRONT MOVES THROUGH
THE AREA...WE ARE EXPECTING A STRONG SQUALL LINE OF SHOWERS WITH
LIMITED...IF ANY...THUNDER. THERE IS A CONCERN THAT SOME OF THE
STRONGER SHOWERS COULD HELP BRING HIGHER WINDS DOWN TO THE
SURFACE...AND BE POTENTIALLY DAMAGING.
OUR OTHER CONCERN FROM WIND INCLUDES GRADIENT PREVAILING WINDS IN
ADVANCE OF THE FRONT. DURING THE AFTERNOON AND EARLY EVENING
HOURS...WIND GUSTS AT THE HIGHER PEAKS ALONG AND WEST OF THE BLUE
RIDGE...MAY SEE WIND GUSTS IN EXCESS OF WIND ADVISORY
CRITERIA...40 KTS. WE ARE REFLECTING THIS CONCERN IN A WIND
ADVISORY THAT WILL BE IN EFFECT FROM NOON WEDNESDAY THROUGH
MIDNIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 345 PM EST TUESDAY...
FRONTAL PASSAGE WEDNESDAY EVENING WILL BRING DRAMATIC CHANGE IN
TEMPERATURE...READINGS FALLING FROM THE 50S/60S WEDNESDAY EVENING
INTO THE 20S/30S DURING THE OVERNIGHT. SLUG OF FRONTAL PRECIP WILL
MOVE RAPIDLY EAST ACROSS THE CWA DURING THE EVENING WITH DOWNPOUR
OF RAIN PRODUCING UPWARDS OF AN INCH OF RAIN IN LESS THAN 2 HOURS
TIME. THIS BURST OF HEAVY RAINFALL WITH THE FRONTAL PASSAGE WILL
LIKELY RESULT IN SUDDEN RISES TO AREA STREAMS. WILL FOREGO FLOOD
WATCH ATTM PER QUICK MOVEMENT OF SYSTEM AND LACK OF SUSTAINED
HEAVY RAIN THREAT. THAT SAID...STILL NOT A GOOD NIGHT TO BE
FLIRTING AROUND LOW WATER CROSSINGS.
FRONTAL PASSAGE HAS SLOWED A BIT COMPARED TO YESTERDAYS MODEL RUNS
BY ABOUT 3 HOURS. LOOKS LIKE FROPA WILL OCCUR AT BLF/TNB BETWEEN
6-8PM...7-9PM AT BCB/ROA...AND 8-10PM AT LYH/DAN. AFTER
FROPA...HEAVY RAIN THREAT WILL END...WINDS SHIFTING AROUND TO THE
WEST-NORTHWEST...TEMPERATURES PLUMMETING BACK TO MORE OF A WINTER
FLAVOR. ANY LINGERING MOISTURE IN THE MOUNTAINS WILL CHANGE TO
SNOW SHOWERS OR FLURRIES...WITH A HALF INCH TO AN INCH OF
ACCUMULATION POSSIBLE AT THE HIGHER ELEVATIONS LATE WEDNESDAY
NIGHT AND EARLY THURSDAY.
FOR THURSDAY AND INTO THE WEEKEND...COLD UPPER LEVEL TROUGH OF
LOW PRESSURE WILL SET UP SHOP OVER THE EASTERN CONUS...ANY PRECIP
PRODUCTION COMING FROM DISTURBANCES WITHIN THE NORTHERN STREAM.
NEXT OPPORTUNITY FOR PRECIP FROM ONE OF THESE DISTURBANCES WILL
COME THURSDAY NIGHT WITH A ROUND OF SNOW SHOWERS PASSING OVER THE
MOUNTAINS AROUND MIDNIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 305 PM EST TUESDAY...
A LONG WAVE TROF REMAINS OVER THE EASTERN CONUS FOR THE WEEKEND. SFC
HIGH CENTERED ALONG THE CAROLINA COAST SATURDAY WILL MOVE EAST INTO
THE ATLANTIC OCEAN. A CLIPPER-LOW AND ATTENDING SURFACE COLD FRONT
APPROACHES FROM THE WEST SATURDAY AND TRAVELS ACROSS FORECAST AREA
SATURDAY NIGHT INTO SUNDAY MORNING. THE GFS SUGGEST THAT A COUPLE OF
INCHES OF SNOW ACCUMULATION IS POSSIBLE IN THE WESTERN UPSLOPE
AREAS. THE ECMWF HINTS AT LIGHTER SNOW TOTALS. KEPT SNOW SHOWERS IN
THE NORTHWEST UPSLOPE FLOW FOR SUNDAY MORNING INTO SUNDAY AFTERNOON
LEANING TOWARDS GFS THEN TAPER OFF AS THE TROF AXIS MOVES FURTHER
INTO THE ATLANTIC.
HIGH PRESSURE BUILDS ACROSS THE REGION SUNDAY NIGHT INTO MONDAY
MORNING. ANOTHER LOW PRESSURE CENTER LIFTS NORTHEAST ACROSS GREAT
LAKES AND PUSHES A COLD FRONT TOWARDS OUR REGION MONDAY. THE COLD
FRONT ADVANCES ACROSS OUR REGION MONDAY NIGHT INTO TUESDAY. THE
GFS DEVELOPS A LOW PRESSURE CENTER OFF THE VIRGINIA COAST MONDAY
NIGHT AND LIFTS IT NORTHWARD ON TUESDAY. THE GFS SOLUTION
INDICATED THAT MORE SNOW...SEVERAL INCHES ARE POSSIBLE IN THE
WESTERN UPSLOPE AREAS ON MONDAY NIGHT INTO TUESDAY. WENT WITH
SCATTERED POPS FOR MONDAY NIGHT INTO TUESDAY AND WILL WATCH FOR
FURTHER RUNS TO SEE EVOLUTION AND DETAILS OF THIS STORM FOR EARLY
NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1135 PM EST TUESDAY...
CEILINGS WILL LOWER FROM SOUTHWEST TO NORTHEAST OVERNIGHT.
EXPECTING MVFR CEILINGS AT ROA/LYH AND DAN BY 12Z. LIGHT RAIN
ALONG THE BLUE RIDGE AND IN THE FOOTHILLS MAY OCCASIONALLY REDUCE
THE VISIBILITY AT LOCAL AIRPORTS BEFORE 15Z.
AN INTENSE COLD FRONT REACHES THE FORECAST AREA BY WEDNESDAY
AFTERNOON. WINDS AHEAD OF THIS FRONT JUST ABOVE THE SURFACE WILL
BE INCREASING ABOVE 50 KNOTS WHICH IS REFLECTED IN THE LLWS PART
OF THE TAFS. BY AFTERNOON HIGH CONFIDENCE THERE WILL BE ENOUGH
MIXING TO BRING WIND GUSTS DOWN TO THE SURFACE OF 30 TO 40 KNOTS.
THE FRONT WILL PRODUCE A BROAD BAND OF SHOWERS AND POSSIBLY
ISOLATED THUNDERSTORMS WITH HEAVY RAIN AND MVFR VISIBILITIES.
MODELS AND BUFKIT SHOWED A SHARP WIND SHIFT TO THE WEST WITH THE
FRONTAL PASSAGE. WINDS WILL STILL BE GUSTY BEHIND THE FRONT
WEDNESDAY NIGHT.
AS MUCH COLDER AIR ARRIVES BY THURSDAY...UPSLOPE SNOW SHOWERS
WILL DEVELOP FOR KBLF AND KLWB...WITH CLEARING EAST OF THE BLUE
RIDGE. NORTHWEST FLOW WILL PREVAIL FRIDAY THROUGH SUNDAY WITH
POTENTIAL FOR TWO CLIPPER SYSTEMS TO BRING SNOW TO THE
MOUNTAINS...ONE LATE THURSDAY NIGHT INTO FRIDAY AND THE NEXT
SATURDAY INTO SUNDAY.
&&
.HYDROLOGY...
AN INCH /1.00/ TO AND INCH AND A HALF /1.50/ OF RAIN IS
ANTICIPATED WITH THE FRONTAL PASSAGE WEDNESDAY EVENING. THE BULK
OF THIS RAIN WILL BE ASSOCIATED WITH A SQUALL LINE OF SHOWERS
ASSOCIATED WITH A FRONTAL PASSAGE...MOST OF THIS RAIN OCCURRING IN
LESS THAN 2 HOURS. DUE TO THE SHORT DURATION OF THE HEAVY
RAINFALL...EXPECT RAPID RISES ALONG AREA STREAMS. AS LONG AS THE
RAINFALL AMOUNTS REMAIN BELOW 1.5 INCHES...FLOODING SHOULD BE KEPT
TO A MINIMUM.
ENSEMBLE FORECASTS SUGGEST THERE WILL ALSO BE SOME RESPECTABLE
RISES ON THE AREA RIVERS. 1.50 INCHES OF RAIN WILL CAUSE RIVERS
TO RISE TO NEAR BANKFULL. IF RAIN AMOUNTS EXCEED 1.50 INCHES OVER
ANY GIVEN BASIN...THEN RIVER FLOODING WOULD BECOME AN ISSUE.
ATTM...CURRENT FORECASTS REFLECT BASIN AVERAGE AMOUNTS CLOSER TO
1.25 INCHES.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY FROM NOON WEDNESDAY TO MIDNIGHT EST WEDNESDAY
NIGHT FOR VAZ011-013-014-016>020-022>024-032>035-043>047-
058-059.
HIGH WIND WARNING FROM 4 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR VAZ007-009-010-012-015.
NC...WIND ADVISORY FROM NOON WEDNESDAY TO MIDNIGHT EST WEDNESDAY
NIGHT FOR NCZ002>006-019-020.
HIGH WIND WARNING FROM 4 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NCZ001-018.
WV...WIND ADVISORY FROM NOON WEDNESDAY TO MIDNIGHT EST WEDNESDAY
NIGHT FOR WVZ043>045.
HIGH WIND WARNING FROM 4 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR WVZ042.
&&
$$
SYNOPSIS...AMS/RAB
NEAR TERM...AMS/DS
SHORT TERM...PM
LONG TERM...KK
AVIATION...AMS/KK
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 AM CST WED JAN 30 2013
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
353 AM CST WED JAN 30 2013
MAIN FORECAST CONCERNS THIS PACKAGE...WINTER STORM/SNOW AMOUNTS/
WINDS TODAY...TEMPERATURE TRENDS AND INTERMITTENT -SN/FLURRY
CHANCES TONIGHT THRU FRI NIGHT.
06Z SURFACE ANALYSIS HAD THE SFC LOW DEEPENING OVER LOWER MI WITH
ARCTIC HIGH PRESSURE BUILDING INTO MT. PRESSURE GRADIENT WAS
INCREASING ACROSS THE REGION...WITH NORTH TO NORTHWEST WINDS
BRINGING IN COLDER AIR AND ERODING THE WARM LAYER ALOFT. -SN IN
THE FCST AREA BEING REPORTED AS FAR SOUTHEAST AS KOLZ/KOVS AS OF
0630Z. WV IMAGERY SHOWED A VIGOROUS SHORTWAVE LIFTING THRU THE
CENTRAL/SOUTHERN PLAINS AND TOWARD THE REGION. MAIN DEFORMATION BAND
OF SNOW WITH THIS FEATURE WAS LIFTING FROM NORTHEAST KS/SOUTHEAST
NEB AND MUCH OF THE SOUTHWEST HALF OF IA...MAKING STEADY BUT DELAYED
PROGRESS NORTHEAST TOWARD THE AREA.
NO GLARING ERRORS NOTED WITH 30.00Z MODEL INITIALIZATIONS. GIVEN THE
PASSING STRONG MID LEVEL TROUGH TODAY/TONIGHT AND FLOW TRANSITIONING
TO NORTHWEST...SOLUTIONS AS SIMILAR AS CAN BE EXPECTED FOR TODAY
THRU FRI NIGHT. DPROG/DT OF 500MB HGTS AT 30.00Z SHOWED THE SLOWER/
STRONGER MODEL RUNS OF 28.00Z AND 29.00Z VERIFIED BEST WITH THE
TROUGH OVER THE CENTRAL CONUS. ALL WERE VERY GOOD WITH THE EAST/WEST
NOAM COAST RIDGING. ECMWF WITH THE BETTER RUN-TO-RUN CONSISTENCY.
MODEL CONSENSUS TRENDS SLOWER AS THE MAIN TROUGH/ENERGY MOVES INTO
THE NORTHEAST CONUS BY 12Z THU. TREND CONTINUES A BIT STRONGER WITH
A NORTHERN STREAM SHORTWAVE TO DROPS ACROSS MN/WI ON THU.
CONSISTENCY GOOD FOR THU NIGHT THRU FRI NIGHT AS NORTHWEST FLOW
ALOFT BECOMES ESTABLISHED OVER THE REGION...BUT DIFFERENCES ON
DETAILS OF MINOR SHORTWAVES IN THIS FLOW. ECMWF WITH THE BETTER
OVERALL RUN-TO-RUN CONSISTENCY TODAY INTO FRI NIGHT. CHECK OF OBS
VS. MODEL DATA AT 06Z SHOWED A CONSENSUS LOOKED BEST AS THE SFC LOW
DEEPENED OVER LOWER MI. PER WV IMAGERY MODELS ALL LOOK REASONABLE
WITH THE SHORTWAVE ENERGY ROTATING AROUND THE EAST SIDE OF THE
TROUGH AND TOWARD THE UPPER MIDWEST. ECMWF/NAM LOOKED BEST WITH THE
00-06Z PRECIP ACROSS THE MID/UPPER MS VALLEY. FAVORED A MODEL/
ENSEMBLE CONSENSUS WEIGHTED TOWARD THE ECMWF WITH ITS BETTER RUN-TO-
RUN CONSISTENCY AND PERFORMANCE WITH THE 00-06Z MID-CONUS PRECIP.
SHORT TERM FCST CONFIDENCE AVERAGE TO GOOD THIS CYCLE.
IN THE SHORT TERM...TODAY IS ALREADY PROBLEMATIC DUE TO AN EASTWARD
SHIFT OF THE MODEL CONSENSUS WITH QPF /SNOW/ PRODUCTION AND
INHERITED HEADLINES. DEFORMATION BAND OF SNOW ASSOCIATED WITH THE
STRONG MID LEVEL SHORTWAVE AND MDT/STRONG 850-500MB FN CONVERGENCE
STILL TRANSLATES ACROSS THE AREA TODAY. WITH ALL THE MID MS/LOWER
OH VALLEY CONVECTION DRIVING THE TROUGH/COLD FRONT EAST...AND
INTERCEPTING A LOT OF THE MOISTURE...SHORTWAVE PV ADVECTION/
DIVERGENCE ALOFT AND LOWER/MID LEVEL FN FORCING APPEAR TO HAVE LESS
MOISTURE TO WORK WITH THAN EARLIER MODEL RUNS INDICATED. ANOTHER
THING WORKING AGAINST HEAVIER QPF/SNOW THRU TODAY IS FASTER MOVEMENT
OF THE FORCING ACROSS THE AREA. WHAT LOOKED LIKE IT MIGHT BE 18HRS
OF FORCING/LIFT NOW LOOKS MORE LIKE 9-12HRS AS THE SHORTWAVE PASSES.
ALL THIS TRENDS TOWARD LESS SNOW FOR THE AREA EARLY THIS MORNING AND
TODAY.
HAVE ALREADY CANCELED ADVISORIES AND REDUCED WINTER STORM WARNING TO
ADVISORY ALONG/NORTHWEST OF A NEW HAMPTON IA-LA CROSSE-BLACK RIVER
FALLS LINE. WARNING CONTINUES TO LOOK GOOD ACROSS THE SOUTHEAST 1/3
TO HALF OF THE FCST AREA. MAY NOT QUITE GET 6 INCHES OF SNOW...BUT
BLOWING/DRIFTING LATER AS NORTHWEST GRADIENT WINDS CONTINUE TO
INCREASE ALONG/SOUTHEAST OF A KOLZ-VIROQUA-NECEDAH WI LINE LOOKING
TO MAKE FOR MISERABLE TRAVEL TODAY IN THOSE AREAS. SYSTEM EXITS
QUICKLY DURING THE MID/LATE AFTERNOON HOURS AND MAY BE ABLE TO
CANCEL SOME HEADLINES EARLY...ESPECIALLY WEST OF THE MS RIVER.
ARCTIC AIR POURS INTO THE AREA BEHIND THE DEPARTING LOW TONIGHT.
GRADIENT REMAINS TIGHT FOR NORTHWEST WINDS OF 10 TO 20 MPH INTO THU
MORNING AS TEMPERATURES HEAD TO NEAR AND BELOW ZERO...PRODUCING
WINDS CHILLS OF 20-25 BELOW OVER THE WEST 1/3 OF THE FCST AREA. WILL
ISSUE A WIND CHILL ADVISORY ALONG/WEST OF A WABASHA MN TO NEW
HAMPTON IA LINE FOR LATE TONIGHT/THU MORNING.
THE NORTHERN STREAM SHORTWAVE DROPS ACROSS THE AREA LATE TONIGHT/THU
WITH DEEP CYCLONIC CONVERGENCE...RATHER DEEP MOISTURE AND STEEP LOW
LEVEL LAPSE RATES ON THU. RAISED -SN CHANCES TO 60 PERCENT ACROSS
THE NORTH END OF THE FCST AREA AND 20-50 PERCENT ELSEWHERE ACROSS
THE NORTHEAST HALF OF THE FCST AREA FOR TONIGHT/THU...FOR OCCASIONAL
VERY LIGHT SNOW THAT MAY SEE SOME 1/2 INCH ACCUMULATIONS OF FLUFF.
EVEN COLDER AIRMASS SETTLES OVER THE AREA THU NIGHT WITH 925MB TEMPS
IN THE -20C TO -26C RANGE...DEPENDING ON SPECIFIC MODEL DETAILS.
WINDS WILL BE LIGHTER...MORE IN THE 5-10MPH RANGE BUT TEMPS AROUND
12Z FRIDAY LOOKING TO BE IN THE -8F TO -16F RANGE. WIND CHILLS THU
NIGHT/FRI MORNING HEADED INTO THE -20 TO -35 RANGE AND ANOTHER WIND
CHILL ADVISORY WILL BE NEEDED. WILL NOT COMPLICATE HEADLINE PICTURE
ANY FURTHER AND LEAVE THIS ONE TO BE ISSUED LATER.
DETAILS DIFFER AMONG THE MODELS BY FRI/FRI NIGHT BUT ALL DROP
ANOTHER STRONGER SHORTWAVE SOUTHEAST ACROSS THE GREAT LAKES...ALONG
WITH A WEAKER ONE SOUTHEAST ACROSS THE NORTHERN PLAINS. THIS SETS
OFF A ROUND OF MDT TO STRONG 925-700MB WARM ADVECTION LIFT ACROSS
THE REGION. THE QUESTION IS HOW MUCH MOISTURE WILL THERE BE AND
WHERE WILL THE STRONGER OF THE ISENTROPIC LIFT/VERTICAL MOTION
OCCUR. MODEL CONSENSUS KEEPS THE SFC-850MB LAYER DRY FRI SO WILL
LEAVE FRI DRY FOR NOW. SMALL -SN CHANCE FRI NIGHT REASONABLE WITH
BETTER INDICATION FOR SFC TO AT LEAST 800MB SATURATION BEING PUSHED
INTO THE COLD AIRMASS OVER THE AREA.
FAVORING A MODEL/ENSEMBLE CONSENSUS LEAD BY THE ECMWF...USED A BLEND
OF THE NUMERICAL TEMPERATURE GUIDANCE WEIGHTED TOWARD THE ECMWF FOR
HIGHS/LOWS TODAY THRU FRI NIGHT. TEMPS TO FALL TODAY AS THE ARCTIC
AIRMASS SPREADS IN...WITH HIGHS AROUND 12-13Z THIS MORNING. FOR THU
NIGHT LOWS...IF WINDS BECOME LIGHT/VARIABLE CALM OVER THE FRESH SNOW
COVER IN THE -20C TO -26C 925MB AIRMASS...LOWS IN SOME OF THE
SHELTERED VALLEYS/NORMALLY COLDER LOW LAYING AREAS COULD DROP INTO
THE -20F TO -30F RANGE.
.LONG TERM...SATURDAY THROUGH TUESDAY...
353 AM CST WED JAN 30 2013
NOT A LOT OF TIME SPENT IN THE DAY 4-7 PERIOD AGAIN THIS MORNING
WITH ALL THE ISSUES AND HEADLINES IN THE SHORT TERM. 30.00Z MEDIUM
RANGE MODELS IN RATHER GOOD AGREEMENT SAT FOR YET ANOTHER STRONGER
NORTHWEST FLOW SHORTWAVE TO DROP SOUTHEAST ACROSS THE REGION...THIS
ONE ACROSS MN/WI...OVER WHAT WILL STILL BE A RATHER COLD AND EASIER
TO SATURATE AIRMASS/COLUMN. SMALL -SN CHANCE SAT LOOKS REASONABLE.
GOOD CONSENSUS FOR THE FLOW TO FLATTEN A BIT/BECOME MORE WEST-
NORTHWEST SUN INTO MON WITH YET ANOTHER SHORTWAVE TO DROP SOUTHEAST
ACROSS THE REGION. MAY YET NEED SMALL -SN CHANCES OVER MUCH OF THE
FCST AREA SUN DEPENDING ON DETAILS/WHERE THIS WAVE AND ATTENDANT SFC
LOW TRACK. AREA REMAINS UNDER NORTHWEST FLOW ALOFT MON/TUE BUT
MODELS DIVERGING WITH TIMING OF UNIDENTIFIABLE SHORTWAVES THRU THE
FLOW. FCST CONFIDENCE IN THE LONG TERM LOOKS AVERAGE. GIVEN THIS AND
NOT A LOT TIME PICKING THRU THE DETAILS...LITTLE IF ANY CHANGES MADE
TO THE THE MODEL/ENSEMBLE CONSENSUS DATA IN THE DAY 4-7 FCST GRIDS.
&&
.AVIATION...THROUGH 06Z THURSDAY
1105 PM CST TUE JAN 29 2013
THE SURFACE LOW HAS MOVED SLOWLY OUT OF NORTHWEST ARKANSAS INTO
SOUTH CENTRAL MISSOURI THIS EVENING. THIS HAS RESULTED IN A SLOW
NORTHWARD PUSH OF THE SNOW FROM SOUTHWEST IOWA INTO CENTRAL IOWA.
THE 30.00Z NAM AND 30.02Z HRRR CONTINUE TO HAVE A GOOD HANDLE ON
HOW THE PRECIPITATION HAS BEEN EVOLVING THIS EVENING WITH BOTH
MODELS SUGGESTING THAT KLSE HAS A BETTER CHANCE OF GETTING INTO
THE PRECIPITATION THAN KRST DOES. WITH THE NORTHEAST MOVEMENT OF
THE SNOW...IT IS EXPECTED TO START MOVING INTO KLSE LATE TONIGHT
AND KRST AROUND 12Z WITH VISIBILITIES GOING DOWN TO MVFR. AS THE
MODERATE TO STRONG FRONTOGENESIS IN THE 750-500 MB LAYER COMES
ACROSS WEDNESDAY MORNING...THE SNOW SHOULD INTENSIFY BUT WITH THE
BEST ISENTROPIC UP GLIDE ON THE 290K SURFACE REMAINING SOUTHEAST
OF BOTH TAF SITES...NOT EXPECTING THE HEAVIEST BAND OF SNOW TO
IMPACT EITHER TAF SITE. BOTH SITES SHOULD STILL SEE IFR CONDITIONS
BUT THE VISIBILITY SHOULD BE LOWER AT KLSE. KRST WILL SEE
IMPROVEMENT STARTING ALREADY LATE WEDNESDAY MORNING AND IN THE EARLY
AFTERNOON OR KLSE AS CONDITIONS GO BACK TO MVFR. SOME FLURRIES
EXPECTED TO HANG ON DURING THE AFTERNOON WITH VFR VISIBILITY BUT
LOOK FOR THE CEILINGS TO REMAIN MVFR FOR THE REMAINDER OF THE
PERIOD. THE TIGHT GRADIENT AROUND THE SURFACE LOW WILL PRODUCE
SUSTAINED NORTH TO NORTHWEST WINDS OF 15 TO 20 KNOTS WITH GUSTS OF
25 TO 30. THE NAM BUFKIT SOUNDINGS SUGGEST THE LOW LEVEL LAPSE RATES
WILL REMAIN STEEP ENOUGH TO KEEP THE GUSTS GOING AFTER SUNSET
WEDNESDAY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
353 AM CST WED JAN 30 2013
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ029-
033-034-041.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR
WIZ042>044-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ088-
095-096.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY
FOR MNZ079-086-087-094-095.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ009-
010-018-019.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY
FOR IAZ008-009-018-019.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ011-
029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
303 AM CST WED JAN 30 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
303 AM CST TUE JAN 29 2013
303 AM UPDATE...30.00Z NAM...HIRES ARW...HIRES NMM AND 30.05Z HRRR
ALL HAVE A GOOD HANDLE ON THE DEFORMATION AREA OF SNOW APPROACHING
FROM IOWA. THE SNOW LOOKS TO SPREAD ACROSS MOST OF THE AREA EXCEPT
FOR TAYLOR COUNTY BY 6 AM. IN ADDITION...THE MODELS FORECAST THAT
THE OVERALL AREA OF SNOW HAS SHIFTED SLIGHTLY TO THE EAST. THIS
REQUIRES SOME ADJUSTMENTS TO THE HAZARDS...DOWNGRADING SOME OF THE
WARNINGS TO ADVISORIES AND REMOVING THE PREVIOUS ADVISORIES. PART
OF THE PROBLEM TOO WITH REACHING THE WARNING CRITERIA IS THAT SNOW
HAS REALLY HELD OFF MUCH OF THE CURRENT NIGHT TIME PERIOD THUS
FAR...DUE TO DRY AIR IN PLACE SEEN ON THE 00Z MPX SOUNDING. IN
ADDITION...THE FORCING WITH THE COMMA HEAD OF THE
SHORTWAVE...CURRENTLY COMING UP THROUGH NORTHWEST MISSOURI...HAS
TAKEN TIME TO REACH THE AREA. WATCH WARNING ADVISORY SEGMENT BELOW
DENOTES THE ADJUSTMENTS TO THE HAZARDS. MORE INFORMATION ABOUT THE
CURRENT SNOW EVENT WILL BE FORTHCOMING IN THE HOUR WITH THE
REGULAR 4 AM ISSUANCE.
PREVIOUS DISCUSSION ISSUED AT 303 PM CST TUE JAN 29
MAIN FORECAST FOCUS IS ON WINTER STORM TONIGHT AND WEDNESDAY WITH
POTENTIAL MIXED PRECIPITATION AT ONSET AND THEN SNOW AMOUNTS AND
BLOWING SNOW. ALSO WIND CHILL FOR WEDNESDAY NIGHT INTO THURSDAY
MORNING.
18Z SURFACE ANALYSIS SHOWS COLD FRONT NOW PUSHING THROUGH SOUTHWEST
WISCONSIN. TEMPERATURES AHEAD OF THE FRONT WERE IN THE MIDDLE 40S IN
GRANT COUNTY AND THE UPPER 50S IN EXTREME NORTHERN ILLINOIS.
MEANWHILE...BEHIND THE FRONT TEMPERATURES GAVE FALLEN INTO THE
MIDDLE 30S. AREA RADAR SHOWING ANOTHER SURGE OF RAIN LIFTING
NORTHWARD THROUGH EASTERN IOWA.
29.12Z DETERMINISTIC MODELS STILL SHOWING SOME DIFFERENCES. GFS/GEM
AND THE 29.00Z ECMWF ALL SHOWING DEFORMATION BAND OF PRECIPITATION
ACROSS THE FORECAST AREA...WHILE NAM APPEARS TO BE THE OUTLIER AND
HAS SHIFTED THE BULK OF THE PRECIPITATION FURTHER SOUTH AND EAST.
HAVE SIDED WITH THE MORE CONSISTENT NON NAM SOLUTIONS.
FOR TONIGHT...COLD AIR SURGES INTO THE AREA BEHIND THE COLD
FRONT...WHILE MOISTURE LIFTS NORTHWARD. THERMAL PROFILES SUGGEST
MAINLY RAIN FOR SOUTHWEST WISCONSIN WITH A SWITCH OVER TO SNOW
TOWARDS MIDNIGHT. THERE COULD BE A BRIEF PERIOD OF SLEET MIXED IN
BEFORE THE CHANGE OVER OCCURS. WITH THE ALREADY SWOLLEN RIVERS FROM
THE EARLIER RAINS AND ADDING ANOTHER .30 INCHES THIS EVENING WILL
LIKELY SEE THE HYDRO PROBLEM CONTINUING AND WILL CONTINUE THE FLOOD
WATCH FOR GRANT COUNTY. THE REMAINDER OF THE AREA WILL SEE ALL SNOW
WITH THE ACCUMULATING SNOW BEGINNING AFTER 06Z.
THE SNOW CONTINUES WEDNESDAY AS ANOTHER SHORTWAVE/SURFACE LOW LIFTS
NORTHEAST ACROSS EASTERN IOWA INTO NORTHERN ILLINOIS. DEFORMATION
BAND OF HEAVY SNOW WILL SET UP ACROSS THE SOUTHEAST HALF OF THE
FORECAST AREA. SOUNDINGS SHOWING STRONG LIFT IN THE DENDRITIC GROWTH
ZONE DURING THE MORNING HOURS. EXPECT SNOW RATIOS IN THE 15:1 TO
18:1 RANGE WHICH SHOULD RESULT INA BAND OF 6 TO 9 INCHES OF
SNOW...WITH THE HIGHER AMOUNTS RUNNING FROM AROUND THE
ADAMS/FRIENDSHIP TO CLAYTON COUNTY IOWA LINE. HAVE UPGRADED THE
WATCH AREA TO WARNING...WITH A BORDERING WINTER WEATHER ADVISORY
NORTH OF THE WARNING AREA. IN ADDITION...PRESSURE GRADIENT TIGHTENS
AND WINDS LOOK TO GUST TO 20 TO 30 MPH WHICH WILL CREATE SOME
BLOWING SNOW...ESPECIALLY ACROSS THE MORE OPEN AREAS. SNOW WILL
TAPER OFF BY MID TO LATE AFTERNOON...BUT WIT THE WINDS CONTINUING
WILL SEE TE BLOWING AND DRIFTING OF THE SNOW.
ARCTIC AIR WILL CONTINUE TO SURGE INTO THE AREA WEDNESDAY NIGHT.
PRESSURE GRADIENT REMAIN RATHER TIGHT AND WITH TEMPERATURES FALLING
INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO WILL SEE WIND CHILLS
APPROACHING 20 BELOW OVER SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
ARCTIC HIGH THEN BUILDS SOUTHWARD THROUGH THE NORTHERN PLAINS
THURSDAY. 850MB TEMPERATURES BOTTOM OUT IN THE 20 TO 25 BELOW ZERO
RANGE CELSIUS AND WITH THE HIGH STILL OVER THE NORTHERN
PLAINS...WINDS WILL CONTINUE TO BE A FACTOR. VERY LITTLE REBOUND
EXPECTED IN THE AMBIENT TEMPERATURE WIND CHILLS WILL REMAIN IN THE
10 TO 20 BELOW ZERO RANGE. AS THE HIGH SLIPS SOUTH THE RIDGE AXIS
DOES SHIFT ACROSS THE FORECAST AREA THURSDAY NIGHT. IF THIS OCCURS
WILL LIKELY SEE SOMEWHAT LIGHTER WINDS AND GOOD RADIATIONAL COLLING
CONDITIONS. ALONG WITH THIS A LIKELY FRESH SNOWPACK COULD SEE
TEMPERATURES REALLY BOTTOM OUT IN THE TEENS BELOW ZERO. DID LOWER A
FEW DEGREES FROM THE PREVIOUS FORECAST...BUT MAY NEED TO BE LOWERED
MORE. GIVEN WINDS NOT GOING CALM WILL LIKELY NEED WIND CHILL
ADVISORIES FOR MUCH OF THE AREA.
.LONG TERM...
303 PM CST TUE JAN 29 2013
NORTHWEST FLOW CONTINUES ACROSS THE REGION THROUGH THE
WEEKEND...WITH A SURFACE HIGH DRIFTING ACROSS THE AREA. ANOTHER
SHORTWAVE LOOKS TO DROP THROUGH THE FLOW LATE SUNDAY NIGHT AND
MONDAY AND COULD BRING SOME SNOW TO THE AREA. ECMWF FURTHER NORTH
AFFECTING MAINLY NORTHERN AND EASTERN WISCONSIN. FOR NOW KEPT THE
LOWER END PROBABILITIES ACROSS THE FAR NORTH. OTHERWISE...TEMPERATURES
MODERATE SOMEWHAT AHEAD OF THIS SYSTEM TO SLIGHTLY ABOVE
NORMAL...BUT THEN FALL BACK TO NEAR NORMAL ON TUESDAY.
&&
.AVIATION...THROUGH 06Z THURSDAY
1105 PM CST TUE JAN 29 2013
THE SURFACE LOW HAS MOVED SLOWLY OUT OF NORTHWEST ARKANSAS INTO
SOUTH CENTRAL MISSOURI THIS EVENING. THIS HAS RESULTED IN A SLOW
NORTHWARD PUSH OF THE SNOW FROM SOUTHWEST IOWA INTO CENTRAL IOWA.
THE 30.00Z NAM AND 30.02Z HRRR CONTINUE TO HAVE A GOOD HANDLE ON
HOW THE PRECIPITATION HAS BEEN EVOLVING THIS EVENING WITH BOTH
MODELS SUGGESTING THAT KLSE HAS A BETTER CHANCE OF GETTING INTO
THE PRECIPITATION THAN KRST DOES. WITH THE NORTHEAST MOVEMENT OF
THE SNOW...IT IS EXPECTED TO START MOVING INTO KLSE LATE TONIGHT
AND KRST AROUND 12Z WITH VISIBILITIES GOING DOWN TO MVFR. AS THE
MODERATE TO STRONG FRONTOGENESIS IN THE 750-500 MB LAYER COMES
ACROSS WEDNESDAY MORNING...THE SNOW SHOULD INTENSIFY BUT WITH THE
BEST ISENTROPIC UP GLIDE ON THE 290K SURFACE REMAINING SOUTHEAST
OF BOTH TAF SITES...NOT EXPECTING THE HEAVIEST BAND OF SNOW TO
IMPACT EITHER TAF SITE. BOTH SITES SHOULD STILL SEE IFR CONDITIONS
BUT THE VISIBILITY SHOULD BE LOWER AT KLSE. KRST WILL SEE IMPROVEMENT
STARTING ALREADY LATE WEDNESDAY MORNING AND IN THE EARLY AFTERNOON
OR KLSE AS CONDITIONS GO BACK TO MVFR. SOME FLURRIES EXPECTED TO
HANG ON DURING THE AFTERNOON WITH VFR VISIBILITY BUT LOOK FOR THE
CEILINGS TO REMAIN MVFR FOR THE REMAINDER OF THE PERIOD. THE TIGHT
GRADIENT AROUND THE SURFACE LOW WILL PRODUCE SUSTAINED NORTH TO
NORTHWEST WINDS OF 15 TO 20 KNOTS WITH GUSTS OF 25 TO 30. THE NAM
BUFKIT SOUNDINGS SUGGEST THE LOW LEVEL LAPSE RATES WILL REMAIN
STEEP ENOUGH TO KEEP THE GUSTS GOING AFTER SUNSET WEDNESDAY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
303 AM CST WED JAN 30 2013
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ029-
033-034-041.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ042>044-
053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ088-
095-096.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY
FOR MNZ079-086-087-094-095.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ009-
010-018-019.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY
FOR IAZ008-009-018-019.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ011-029-
030.
&&
$$
SHORT TERM...RABERDING/AJ
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CST TUE JAN 29 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
303 PM CST TUE JAN 29 2013
MAIN FORECAST FOCUS IS ON WINTER STORM TONIGHT AND WEDNESDAY WITH
POTENTIAL MIXED PRECIPITATION AT ONSET AND THEN SNOW AMOUNTS AND
BLOWING SNOW. ALSO WIND CHILL FOR WEDNESDAY NIGHT INTO THURSDAY
MORNING.
18Z SURFACE ANALYSIS SHOWS COLD FRONT NOW PUSHING THROUGH SOUTHWEST
WISCONSIN. TEMPERATURES AHEAD OF THE FRONT WERE IN THE MIDDLE 40S IN
GRANT COUNTY AND THE UPPER 50S IN EXTREME NORTHERN ILLINOIS.
MEANWHILE...BEHIND THE FRONT TEMPERATURES GAVE FALLEN INTO THE
MIDDLE 30S. AREA RADAR SHOWING ANOTHER SURGE OF RAIN LIFTING
NORTHWARD THROUGH EASTERN IOWA.
29.12Z DETERMINISTIC MODELS STILL SHOWING SOME DIFFERENCES. GFS/GEM
AND THE 29.00Z ECMWF ALL SHOWING DEFORMATION BAND OF PRECIPITATION
ACROSS THE FORECAST AREA...WHILE NAM APPEARS TO BE THE OUTLIER AND
HAS SHIFTED THE BULK OF THE PRECIPITATION FURTHER SOUTH AND EAST.
HAVE SIDED WITH THE MORE CONSISTENT NON NAM SOLUTIONS.
FOR TONIGHT...COLD AIR SURGES INTO THE AREA BEHIND THE COLD
FRONT...WHILE MOISTURE LIFTS NORTHWARD. THERMAL PROFILES SUGGEST
MAINLY RAIN FOR SOUTHWEST WISCONSIN WITH A SWITCH OVER TO SNOW
TOWARDS MIDNIGHT. THERE COULD BE A BRIEF PERIOD OF SLEET MIXED IN
BEFORE THE CHANGE OVER OCCURS. WITH THE ALREADY SWOLLEN RIVERS FROM
THE EARLIER RAINS AND ADDING ANOTHER .30 INCHES THIS EVENING WILL
LIKELY SEE THE HYDRO PROBLEM CONTINUING AND WILL CONTINUE THE FLOOD
WATCH FOR GRANT COUNTY. THE REMAINDER OF THE AREA WILL SEE ALL SNOW
WITH THE ACCUMULATING SNOW BEGINNING AFTER 06Z.
THE SNOW CONTINUES WEDNESDAY AS ANOTHER SHORTWAVE/SURFACE LOW LIFTS
NORTHEAST ACROSS EASTERN IOWA INTO NORTHERN ILLINOIS. DEFORMATION
BAND OF HEAVY SNOW WILL SET UP ACROSS THE SOUTHEAST HALF OF THE
FORECAST AREA. SOUNDINGS SHOWING STRONG LIFT IN THE DENDRITIC GROWTH
ZONE DURING THE MORNING HOURS. EXPECT SNOW RATIOS IN THE 15:1 TO
18:1 RANGE WHICH SHOULD RESULT INA BAND OF 6 TO 9 INCHES OF
SNOW...WITH THE HIGHER AMOUNTS RUNNING FROM AROUND THE
ADAMS/FRIENDSHIP TO CLAYTON COUNTY IOWA LINE. HAVE UPGRADED THE
WATCH AREA TO WARNING...WITH A BORDERING WINTER WEATHER ADVISORY
NORTH OF THE WARNING AREA. IN ADDITION...PRESSURE GRADIENT TIGHTENS
AND WINDS LOOK TO GUST TO 20 TO 30 MPH WHICH WILL CREATE SOME
BLOWING SNOW...ESPECIALLY ACROSS THE MORE OPEN AREAS. SNOW WILL
TAPER OFF BY MID TO LATE AFTERNOON...BUT WIT THE WINDS CONTINUING
WILL SEE TE BLOWING AND DRIFTING OF THE SNOW.
ARCTIC AIR WILL CONTINUE TO SURGE INTO THE AREA WEDNESDAY NIGHT.
PRESSURE GRADIENT REMAIN RATHER TIGHT AND WITH TEMPERATURES FALLING
INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO WILL SEE WIND CHILLS
APPROACHING 20 BELOW OVER SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
ARCTIC HIGH THEN BUILDS SOUTHWARD THROUGH THE NORTHERN PLAINS
THURSDAY. 850MB TEMPERATURES BOTTOM OUT IN THE 20 TO 25 BELOW ZERO
RANGE CELSIUS AND WITH THE HIGH STILL OVER THE NORTHERN
PLAINS...WINDS WILL CONTINUE TO BE A FACTOR. VERY LITTLE REBOUND
EXPECTED IN THE AMBIENT TEMPERATURE WIND CHILLS WILL REMAIN IN THE
10 TO 20 BELOW ZERO RANGE. AS THE HIGH SLIPS SOUTH THE RIDGE AXIS
DOES SHIFT ACROSS THE FORECAST AREA THURSDAY NIGHT. IF THIS OCCURS
WILL LIKELY SEE SOMEWHAT LIGHTER WINDS AND GOOD RADIATIONAL COLLING
CONDITIONS. ALONG WITH THIS A LIKELY FRESH SNOWPACK COULD SEE
TEMPERATURES REALLY BOTTOM OUT IN THE TEENS BELOW ZERO. DID LOWER A
FEW DEGREES FROM THE PREVIOUS FORECAST...BUT MAY NEED TO BE LOWERED
MORE. GIVEN WINDS NOT GOING CALM WILL LIKELY NEED WIND CHILL
ADVISORIES FOR MUCH OF THE AREA.
.LONG TERM...
303 PM CST TUE JAN 29 2013
NORTHWEST FLOW CONTINUES ACROSS THE REGION THROUGH THE
WEEKEND...WITH A SURFACE HIGH DRIFTING ACROSS THE AREA. ANOTHER
SHORTWAVE LOOKS TO DROP THROUGH THE FLOW LATE SUNDAY NIGHT AND
MONDAY AND COULD BRING SOME SNOW TO THE AREA. ECMWF FURTHER NORTH
AFFECTING MAINLY NORTHERN AND EASTERN WISCONSIN. FOR NOW KEPT THE
LOWER END PROBABILITIES ACROSS THE FAR NORTH. OTHERWISE...TEMPERATURES
MODERATE SOMEWHAT AHEAD OF THIS SYSTEM TO SLIGHTLY ABOVE
NORMAL...BUT THEN FALL BACK TO NEAR NORMAL ON TUESDAY.
&&
.AVIATION...THROUGH 06Z THURSDAY
1105 PM CST TUE JAN 29 2013
THE SURFACE LOW HAS MOVED SLOWLY OUT OF NORTHWEST ARKANSAS INTO
SOUTH CENTRAL MISSOURI THIS EVENING. THIS HAS RESULTED IN A SLOW
NORTHWARD PUSH OF THE SNOW FROM SOUTHWEST IOWA INTO CENTRAL IOWA.
THE 30.00Z NAM AND 30.02Z HRRR CONTINUE TO HAVE A GOOD HANDLE ON
HOW THE PRECIPITATION HAS BEEN EVOLVING THIS EVENING WITH BOTH
MODELS SUGGESTING THAT KLSE HAS A BETTER CHANCE OF GETTING INTO
THE PRECIPITATION THAN KRST DOES. WITH THE NORTHEAST MOVEMENT OF
THE SNOW...IT IS EXPECTED TO START MOVING INTO KLSE LATE TONIGHT
AND KRST AROUND 12Z WITH VISIBILITIES GOING DOWN TO MVFR. AS THE
MODERATE TO STRONG FRONTOGENESIS IN THE 750-500 MB LAYER COMES
ACROSS WEDNESDAY MORNING...THE SNOW SHOULD INTENSIFY BUT WITH THE
BEST ISENTROPIC UP GLIDE ON THE 290K SURFACE REMAINING SOUTHEAST
OF BOTH TAF SITES...NOT EXPECTING THE HEAVIEST BAND OF SNOW TO
IMPACT EITHER TAF SITE. BOTH SITES SHOULD STILL SEE IFR CONDITIONS
BUT THE VISIBILITY SHOULD BE LOWER AT KLSE. KRST WILL SEE IMPROVEMENT
STARTING ALREADY LATE WEDNESDAY MORNING AND IN THE EARLY AFTERNOON
OR KLSE AS CONDITIONS GO BACK TO MVFR. SOME FLURRIES EXPECTED TO
HANG ON DURING THE AFTERNOON WITH VFR VISIBILITY BUT LOOK FOR THE
CEILINGS TO REMAIN MVFR FOR THE REMAINDER OF THE PERIOD. THE TIGHT
GRADIENT AROUND THE SURFACE LOW WILL PRODUCE SUSTAINED NORTH TO
NORTHWEST WINDS OF 15 TO 20 KNOTS WITH GUSTS OF 25 TO 30. THE NAM
BUFKIT SOUNDINGS SUGGEST THE LOW LEVEL LAPSE RATES WILL REMAIN
STEEP ENOUGH TO KEEP THE GUSTS GOING AFTER SUNSET WEDNESDAY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
640 PM CST TUE JAN 29 2013
WI...WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ033-034-041-
042-053.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ017-029-
032.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST WEDNESDAY
FOR WIZ043-044-054-055-061.
MN...WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR MNZ088-095-096.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR MNZ079-086-
087-094.
IA...WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR IAZ009>011-018-
019-029.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR IAZ008.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST WEDNESDAY
FOR IAZ030.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
102 AM EST FRI FEB 1 2013
.SYNOPSIS...
AS A CANADIAN AIR MASS MOVES INTO THE REGION...TEMPERATURES WILL BE
MUCH COLDER TONIGHT WITH A DIMINISHING WIND. LAKE EFFECT SNOW
SHOWERS WILL CONTINUE TO AFFECT THE WESTERN ADIRONDACKS AND MOHAWK
VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT SOUTH AND WEST OF THE
REGION TOMORROW...WITH COLD TEMPERATURES AND BREEZY CONDITIONS.
SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO BE IN PLACE OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1245 AM...LAKE ERIE AND LAKE ONTARIO SNOW BANDS ARE SLOWLY
MIGRATING SOUTHWARD...ESPECIALLY THE LAKE ERIE BAND. LAKE ERIE SNOW
BAND INTO CURRENTLY RUNS THROUGH SCHOHARIE AND ALBANY COUNTIES AND
TAPERS OFF FURTHER TO THE EAST. THE LAKE ONTARIO BAND GENERALLY RUNS
FROM HERKIMER LANDING TO NEAR LAKE GEORGE VILLAGE...AND THEN TAPERS
OFF FURTHER TO THE EAST. HAVE ADJUSTED POP/WX/SNOW AMOUNT GRIDS TO
REFLECT CURRENT POSITION AND FUTURE MOVEMENT OF THESE SNOW BANDS. NO
CHANGE TO THE LAKE EFFECT SNOW HEADLINES CURRENTLY IN EFFECT.
.PREVIOUS DISCUSSION...
AS OF 915 PM...MAIN LAKE EFFECT BAND NOW BECOMING MORE
DISORGANIZED AND SHIFTING SOUTHWARD THROUGH HERKIMER AND HAMILTON
COUNTIES WITH SNOWFALL AMOUNTS GENERALLY IN THE 4-6 RANGE REPORTED
BY LOCAL SPOTTERS. ELSEWHERE...A BAND OF SNOW SHOWERS...AIDED BY
MOHAWK VALLEY CONVERGENCE AND LAKE-ENHANCED MOISTURE HAD REACHED
THE CAPITAL DISTRICT. THIS BAND WILL CONTINUE TO IMPACT THE
CAPITAL REGION THROUGH THE NEXT COUPLE OF HOURS...WITH GENERALLY A
DUSTING TO A FEW TENTHS OF ACCUMULATION.
WINDS ARE STARTING TO DIMINISH SLIGHTLY AS THE PRESSURE GRADIENT
BEGINS TO RELAX. WINDS WILL STILL REMAIN 10-15KTS SUSTAINED WITH
SOME GUSTS OVER 25KTS POSSIBLE UNTIL 3Z. CURRENT FORECAST LOOKS TO
BE SPOT ON. ONLY MINOR CHANGES TO CURRENT TEMPS, DEWPOINTS AND
WIND.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE
WESTERN ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE
NAM12 AND 3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD
DURING THE OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT
MULTI-LAKE CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES
AND STRONG LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD
SUGGEST THAT THIS BAND REACHES WELL INTO OUR AREA. AS A
RESULT...HAVE ALSO INCLUDED A LAKE EFFECT SNOW ADVISORY FOR
HAMILTON COUNTY...IN ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN
HERKIMER. SNOW TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND
3-6 INCHES ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /06Z FRIDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED FOR THE 24 HOUR PERIOD ENDING 06Z
SATURDAY. THE ONLY EXCEPTION WILL BE THE CHANCE FOR SOME LIGHT LAKE
EFFECT SNOW SHOWERS INTO THIS MORNING FOR MAINLY KALB/KGFL/KPSF.
DIFFICULT TO TIME DUE TO IMPENDING MOVEMENT AND EASTWARD EXTENT OF
NARROW SNOW BANDS...SO WILL NOT INCLUDE ANY MENTION OF IFR IN THE
TAFS AT THIS TIME.
OTHERWISE...BRISK CONDITIONS WILL PREVAIL WITH GENERALLY
WEST-NORTHWEST WINDS AROUND 10-20 KT WITH GUSTS OF 25-30 KT.
OUTLOOK...
FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
FOR SPECIFIC RIVER AND LAKE FORECASTS...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/FRUGIS/VTK/IRL
NEAR TERM...GJM/FRUGIS/VTK
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...JPV
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
428 AM EST FRI FEB 1 2013
...BITTERLY COLD THIS MORNING...
.SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
&&
.LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
&&
.AVIATION...
OUTSIDE CONTG LK EFFECT VCNTY KSBN TERMINAL FEW CONCERNS AS ARCTIC
WEDGE DEEPENS FURTHER SHRT TERM. THUS OUTSIDE PD OF IFR CONDS IN
-SHSN AT KSBN XPC CONTD DRYING AND BACKING LL WINDS BY MID MORNING
WILL SHIFT WHATS LEFT OF SNOW BANDS NWD INTO SRN MI W/VFR CONDS.
OTRWS STG GRADIENT FLW WILL CONT W/SFC WIND GUSTS AOA 20KTS
THROUGH THIS MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
INZ003>006-008-009-012>018-020-022>027-032>034.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR
INZ004.
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ079.
LAKE EFFECT SNOW WARNING UNTIL 10 AM EST THIS MORNING FOR MIZ077-
078.
OH...WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ015-016-
024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
352 AM EST FRI FEB 1 2013
.SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
&&
.LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
&&
.MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.AVIATION...ISSUED 1144 PM EST THU JAN 31 2013
//DISCUSSION...
THE COVERAGE AND INTENSITY OF LAKE EFFECT SNOW SHOWERS WILL DIMINISH
DURING THE EARLY MORNING HOURS...WITH THE HIGHER INTENSITY SNOW
BANDS SHIFTING SOUTH OF THE TERMINALS AS THE LOW LEVEL FLOW VEERS
TOWARD THE W-NW. THE FLOW WILL BACK MORE TOWARD THE W-SW FRI
AFTERNOON. INVERSION HEIGHTS WILL BE MUCH LOWER AND THE AMBIENT
AIRMASS DRIER...SO JUST A FEW FLURRIES ARE EXPECTED.
FOR DTW...THE BAND OF HEAVIER SNOW WILL PUSH SOUTH OF THE AIRPORT BY
06 OR 07Z. AFTER WHICH...MAINLY FLURRIES OR LIGHT SNOW SHOWERS WILL
LITTLE TO NO ADDITIONAL ACCUMULATIONS EXPECTED.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT THROUGH THE TAF
PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
348 AM CST FRI FEB 1 2013
.DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.AVIATION...
FOR THE NORTH PLATTE AND VALENTINE TERMINALS THROUGH 12Z SATURDAY.
EXPECT MOSTLY CLOUDY SKIES TODAY AND TONIGHT ACROSS MOST OF WESTERN
AND NORTH CENTRAL NEBRASKA...WITH ABUNDANT MID AND HIGH LEVEL
CLOUDINESS EXPECTED TODAY...AND LOW TO MID LEVEL CLOUD COVER
POSSIBLE TONIGHT. AN UPPER LEVEL DISTURBANCE WILL TRACK FROM THE
DAKOTAS INTO NORTHERN AND EASTERN NEBRASKA THIS AFTERNOON AND EVENING. AS
THIS FEATURE APPROACHES...ABUNDANT MID LEVEL CLOUDINESS WILL DEVELOP
THIS AFTERNOON. CIGS WILL POSSIBLY LOWER TO MVFR LEVELS AT THE KVTN
TERMINAL LATE THIS AFTERNOON AND EARLY THIS EVENING. IN
ADDITION...LIGHT SNOW IS POSSIBLE FRIDAY EVENING...ESPECIALLY OVER
NORTHERN NEBRASKA. VSBYS DOWN TO 3 TO 5 SM ARE POSSIBLE IN ANY AREAS OF
LIGHT SNOW...ESPECIALLY AT THE KVTN TERMINAL. FURTHER SOUTH AT THE
KLBF TERMINAL...MID LEVEL LIFT IS VERY WEAK SO THE THREAT FOR SNOW
IS EXPECTED TO BE MINIMAL. ACROSS NORTHERN NEBRASKA...LIGHT SNOW AND
MVFR CIGS WILL END OVERNIGHT...HOWEVER...OVERCAST VFR SKIES WILL
CONTINUE INTO SATURDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1135 PM CST THU JAN 31 2013
.AVIATION...06Z TAF. KEEPING QUIET WEATHER AND VFR CONDITIONS
GOING IN THE TAF...THOUGH THERE IS A LITTLE MORE UNCERTAINTY AT
THE END OF THE TAF PERIOD WITH WHETHER OR NOT A FEW FLURRIES AND
POTENTIALLY LOWER CEILINGS MOVE INTO THE TERMINAL AREA. A SURFACE
RIDGE AXIS SLIDING THROUGH THE REGION IS BRINGING LIGHT/VARIABLE
WINDS TO THE TERMINAL CURRENTLY...BUT THROUGH THE REST OF THE
OVERNIGHT HOURS...WINDS WILL GRADUALLY BECOME MORE SOUTHERLY AS
THE RIDGE MOVES OFF TO THE EAST. SPEEDS WILL PICK UP A BIT THIS
AFTERNOON...WITH A FEW GUSTS NEAR 20 MPH POSSIBLE...AND THIS
EVENING A FRONTAL BOUNDARY WILL PUSH THROUGH THE TERMINAL
AREA...BRINGING WEST/NORTHWEST WINDS.
&&
.PREV DISCUSSION... /ISSUED 943 PM CST THU JAN 31 2013/
UPDATE...RADAR DATA FROM KUEX...KLNX AND KGLD INDICATE A WEAK
BAND OF PRECIPITATION OVER SOUTHWESTERN NEBRASKA AND NORTHWESTERN
KANSAS...WITH SOME OF THIS ACTIVITY NOW CREEPING INTO EXTREME
SOUTHWESTERN PORTIONS OF OUR CWA. EVENING UPPER AIR ANALYSIS
INDICATES A ~90KT MID LEVEL JET STREAK OVER THE CENTRAL PLAINS
NOW...WITH THE RIGHT-REAR QUADRANT OF THIS JET STREAK MOVING INTO
SOUTHWESTERN NEBRASKA AND NORTHWESTERN KANSAS. THERE APPEARS TO BE
JUST ENOUGH OF A DIRECT THERMAL CIRCULATION AND RESULTANT MID
LEVEL FRONTOGENESIS FOR VERY LIGHT PRECIPITATION PRODUCTION. IT
DOES NOT APPEAR AS THOUGH MUCH OF THIS PRECIPITATION IS MAKING IT
TO THE GROUND HOWEVER AS FORECAST PROXIMITY SOUNDINGS FROM ACROSS
OUR SOUTHWEST...PER THE NAM AND RAP...SUGGEST LOWER TROPOSPHERIC
MOISTURE IS FAIRLY MEAGER. BUT THERE WAS A REPORT OF BRIEF
PRECIPITATION EARLIER THIS EVENING ACROSS EXTREME SOUTHWESTERN
NEBRASKA FROM THIS SAME BAND. THE HRRR SEEMS TO HAVE A GOOD HANDLE
ON THIS SITUATION BY SUGGESTING THIS BAND WILL MEANDER OVER
SOUTHWESTERN PORTIONS OF OUR CWA TONIGHT WHICH MAY PRESENT
PERIODIC SNOW FLURRIES TO THOSE AREAS. AS A RESULT...WENT AHEAD
AND INTRODUCED FLURRIES TO THE FORECAST FOR TONIGHT ACROSS OUR
SOUTHWEST. THE REMAINDER OF THE FORECAST REMAINS IN GREAT
SHAPE...WITH ONLY A FEW MINOR CHANGES MADE TO HOURLY
TEMPERATURE...WIND...DEWPOINT AND SKY GRIDS TO BETTER REFLECT
CURRENT OBSERVATIONS.
PREV DISCUSSION... /ISSUED 407 PM CST THU JAN 31 2013/
SHORT TERM...TONIGHT AND FRIDAY.
WE REMAIN IN NORTHWEST FLOW ALOFT FOR THE SHORT TERM. THE SURFACE
HIGH...CENTERED OVER THE NORTHERN PLAINS WILL SHIFT EAST...PLACING
US WITHIN RETURN FLOW BY THE OVERNIGHT.
TEMPERATURES SHOULD DROP SHARPLY TONIGHT AS WIND DROPS OFF...BUT
STEADY OUT FOR THE OVERNIGHT AS WIND SHIFTS TO THE SOUTH AND
INCREASES A BIT TOWARD DAWN. LOWS WILL LARGELY BE IN THE SINGLE
DIGITS...BUT COULD HAVE BEEN COLDER IF NOT FOR THE RETURN FLOW.
LOOKS LIKE WE ARE JUST FAR ENOUGH SOUTHWEST TO PRECLUDE ANY WIND
CHILL ISSUES...AS WAS THE CASE EARLY THIS MORNING.
MAINLY A TEMPERATURE FORECAST FOR FRIDAY AS SOUTHWEST FLOW FOLLOWS
THE FETCH OF THE SNOW FIELD...WHICH SHOULD HAMPER HIGH TEMPERATURE
WHERE THERE IS SNOW...SO I ESSENTIALLY LOWERED HIGHS OVER THE SNOW
PACK...AND RAISED TEMPERATURES A BIT IN THE NORTHWESTERN
CWA...INCLUDING ORD. SKY COVER WILL INCREASE ESPECIALLY TOWARD
AFTERNOON AS ANOTHER SHORTWAVE TROUGH APPROACHES WITHING NORTHWEST
FLOW. WE WILL BE NEAR THE ENTRANCE REGION OF AN UPPER LEVEL JET
STREAK...WHICH COULD INDUCE SOME FLURRIES IN OUR NORTHERN CWA BY
LATE AFTERNOON..ESPECIALLY NEAR AN UNUSUALLY ORIENTED WARM FRONT
APPROACHING FROM THE WEST. MOST MODELS DO NOT INDICATE ANY SNOW
FLURRY ACTIVITY...BUT THE NMM AND TO SOME EXTENT..THE GFS SHOW THIS
TO BE A POSSIBILITY...SO INCLUDING THIS FOR THE VERY LATE AFTERNOON.
WIND WILL INCREASE FROM THE SOUTH AHEAD OF THE WARM FRONT MOVING IN
FROM THE WEST BY AFTERNOON...BUT AGAIN...THE FETCH OF THE WIND AND
INCREASING CLOUDINESS WILL ROB US ONCE AGAIN OF A POTENTIALLY MORE
MILD DAY FOR THE MAJORITY OF OUR CWA.
LONG TERM...FRIDAY EVENING THROUGH NEXT THURSDAY. FIRST OFF...VERY
FEW NOTICEABLE CHANGES WERE MADE FROM THE PREVIOUS FORECAST...AS THE
MAIN THEME CONTINUES TO BE PRECIPITATION-FREE CONDITIONS WITH THE
POSSIBLE EXCEPTION OF FRIDAY EVENING MAINLY IN THE NORTHEAST...AND
A SEVERAL-DAY STRETCH OF DECENT TEMPERATURES AVERAGING AROUND 10
DEGREES ABOVE NORMAL.
STARTING OFF FRIDAY NIGHT...MAIN CHANGE FROM PREVIOUS FORECAST IS
THE INTRODUCTION OF A CHANCE/SLIGHT CHANCE OF FLURRIES DURING THE
EVENING HOURS MAINLY ACROSS OUR NORTHEAST 1/2...OR ROUGHLY
NORTHEAST OF A LOUP CITY-SUPERIOR LINE. THERE IS GOOD AGREEMENT
AMONGST VARIOUS 12Z MODELS SUCH AS THE NAM/GFS/ECMWF THAT A LOW
AMPLITUDE SHORTWAVE TROUGH WILL PASS EAST-SOUTHEAST OVER THE AREA
THROUGH THE NIGHT...FOCUSED WITHIN THE ENTRANCE REGION OF A 100+KT
JET AT 300MB. ALTHOUGH FORCING IS NOT GREAT WITH THIS WAVE...THERE
APPEARS TO BE INCREASING CHANCES OF AT LEAST LIGHT MEASURABLE SNOW
ALONG AN AXIS FROM NORTHEAST NEB INTO IA. AT THIS POINT...AM
THINKING THAT THESE MEASURABLE CHANCES SHOULD REMAIN JUST
NORTHEAST OF OUR CWA...BUT IT COULD BE A VERY CLOSE CALL
ESPECIALLY PER THE FORECAST REFLECTIVITY OF THE 12Z 4K WRF-NMM...AND
SOMETHING FOR NEXT FEW SHIFTS TO WATCH. IN THE MEANTIME...AT LEAST
WANTED TO GET THE NON-MEASURABLE FLURRY WORDING GOING...AS NAM
FORECAST SOUNDINGS SUGGEST A FAIRLY DEEP SATURATED LAYER ABOVE
850MB. FOR NOW WILL RUN WITH THE THINKING THAT ANY FLURRY
POTENTIAL WILL END ACROSS OUR CWA BY MIDNIGHT AS FORCING PASSES
MORE TO THE EAST. AT THE SURFACE...THE PASSING UPPER WAVE WILL
DRAG A SURFACE TROUGH ACROSS THE CWA THROUGH THE NIGHT...TURNING
BREEZES FROM THE WEST-NORTHWEST AT AROUND 10-15 MPH AS IT PASSES.
OFTEN...TEMPS TEND TO JUMP AT LEAST A FEW DEGREES AS THESE TROUGHS
PASS EVEN IN THE MIDDLE OF THE NIGHT...BUT GIVEN THIS IS STILL 3
PERIODS OUT WILL NOT ADVERTISE A NON-DIURNAL TEMP CURVE AT THIS
TIME. FOR ACTUAL LOWS...MADE LITTLE CHANGE WITH LOW 20S ADVERTISED ALL
AREAS...ALTHOUGH WOULD NOT BE SURPRISED TO SEE SOUTHEAST AREAS
OVER THE DEEPER SNOW COVER TRY DROPPING INTO THE TEENS BEFORE
MIXING BEHIND THE PASSING TROUGH LINE PICKS UP A BIT. ON ONE LAST
FRIDAY NIGHT NOTE...THE SREF VISIBILITY PROGS ARE SUGGESTING SOME
FOG DEVELOPMENT OVER THE MELTING SNOW PACK DURING THE NIGHT...BUT
THINKING THE WESTERLY WINDS BEHIND THE TROUGH AXIS SHOULD PROVE
UNFAVORABLE FOR ANY FOG WORTH MENTIONING.
SATURDAY/SATURDAY NIGHT...CONFIDENCE IS RATHER HIGH IN A DRY 24
HOURS...AS MID LEVEL HEIGHTS START TO RISE A BIT AS MID LEVEL
TROUGHING MOVES OFF THE TO THE EAST. AS IT DOES SO...COULD SEE
ADDITIONAL SNOW BANDS DEVELOP NEAR/MAINLY EAST OF THE IA/NEB BORDER
DURING THE DAY...BUT THIS SHOULD STAY SQUARELY EAST OF OUR CWA. IN
THE LOW LEVELS...WESTERLY WINDS WILL PICK UP A BIT TOWARD BREEZY
TERRITORY DURING THE DAY...WITH SUSTAINED SPEEDS INCREASING TO AT
LEAST 15-20 MPH FOR A FEW HOURS. NEEDLESS TO SAY...THE BATTLE
BETWEEN THIS WARMING DOWNSLOPE FLOW AND THE LINGERING SNOW PACK
ACROSS MAINLY THE SOUTHEAST 1/2 OF THE CWA MAKES FOR A TRICKY AND
SOMEWHAT LOW CONFIDENCE HIGH TEMPERATURE FORECAST. FOR NOW...WILL
KEEP THEME SIMILAR TO PREVIOUS WITH MAINLY UPPER 40S/NEAR 50 WHERE
SNOW IS NONE/MINIMAL...AND ONLY LOW 40S IN SOUTHEAST COUNTIES
WHERE IT IS DEEPER. COULD EASILY SEE SOME 5+ DEGREE ERRORS HERE
DEPENDING ON HOW MUCH EFFECT THE SNOW FIELD HAS. ALTHOUGH NOT AS
STRONG AS DURING THE DAY...PERSISTENT STEADY WESTERLY BREEZES
OVERNIGHT SHOULD AGAIN HOLD LOW TEMPS UP IN THE LOW 20S MOST ALL
AREAS.
SUNDAY/SUNDAY NIGHT...FAIRLY UNEVENTFUL NORTHWEST FLOW ALOFT
CONTINUES...DESPITE A FEW VERY LOW AMPLITUDE SHORTWAVE TROUGHS
PASSING THROUGH THE FLOW. LOOKS AT THIS POINT LIKE ANY PRECIP
SHOULD FOCUS AT LEAST LEAST FEW HUNDRED MILES NORTHEAST AND/OR
SOUTH OF THE CWA. ALTHOUGH TEMPS AT 850MB SHOULD AVERAGE A BIT
WARMER THAN SATURDAY...BREEZES WILL LIKELY BE A BIT LIGHTER AND
MORE FROM THE SOUTHWEST. THE NET RESULT IS ALMOST IDENTICALLY
FORECAST HIGH TEMPERATURES TO SATURDAY IN MOST AREAS...WITH MAINLY
UPPER 40S...EXCEPT SLIGHTLY COOLER MID 40S OVER THE DEEPER SNOW.
MONDAY/MONDAY NIGHT...THE REGION REMAINS UNDER NORTHWEST FLOW
BETWEEN A RIDGE BUILDING OVER THE WESTERN CONUS...AND THE NEXT IN
A PARADE OF CHANNELED SHORTWAVE TROUGHS SLIDING SOUTHEAST OUT OF
CANADA ACROSS THE DAKOTAS/IA. AGAIN...ANY PRECIPITATION ALONG THIS
SHORTWAVE AXIS SHOULD FOCUS AT LEAST A FEW HUNDRED MILES TO OUR
EAST...WHILE WE REMAIN IN THE MILDER AIR ON THE WARMER SIDE OF THE
UPPER JET. HIGH TEMPS FOLLOW CLOSELY TO ALLBLEND MODEL
CONSENSUS...WITH UPPER 40S MOST NEB ZONES AND LOW/MID 50S
SOUTHWEST.
TUESDAY/TUESDAY NIGHT...THE FLOW ALOFT TRANSITIONS MORE ZONAL IN
THE WAKE OF THE VIGOROUS MIDWEST SHORTWAVE TROUGH THAT QUICKLY
DEPARTS TOWARD THE MID-ATLANTIC REGION. WITH LITTLE FORESEEABLE
CHANGE IN THE LOW LEVEL TEMPERATURE FIELDS...HIGH TEMPS ARE
FORECAST VERY SIMILAR TO MONDAY...RANGING FROM MID 40S NORTHEAST
TO LOW 50S SOUTHWEST.
WEDNESDAY/WEDNESDAY NIGHT...THINGS START TO TURN A BIT MORE
INTERESTING ALOFT...AS BOTH THE ECWMF/GFS ARE IN SURPRISINGLY GOOD
AGREEMENT AS A SLOWLY DEEPENING BUT PROGRESSIVE SHORTWAVE TROUGH
DROPS OUT OF THE NORTHERN ROCKIES TOWARD THE NORTHERN/CENTRAL
PLAINS...ABUT AT LEAST FOR NOW OUR LOCAL PRECIP CHANCES APPEAR
QUITE MINIMAL WITH BETTER FORCING/MOISTURE FOCUSING OFF TO OUR
EAST/SOUTHEAST...ALTHOUGH IT COULD BE A CLOSE CALL ESPECIALLY PER
THE GFS. SOMETHING TO WATCH. MODEL CONSENSUS HIGHS ARE YET AGAIN A
NEAR COPY OF THE PREVIOUS FEW DAYS...UPPER 40S NORTHEAST TO MID
50S SOUTHWEST.
THURSDAY...COULD SEE AT LEAST A SLIGHT COOL-DOWN BEHIND A SURFACE
COLD FRONT THAT PASSES THROUGH WEDNESDAY NIGHT...AND ITS VERY
POSSIBLE THAT CURRENTLY FORECAST TEMPS MAINLY IN THE UPPER 40S TO
LOW 50S COULD BE A BIT TOO WARM. ALOFT...THE AFOREMENTIONED UPPER
WAVE STARTS TO PASS EAST/SOUTHEAST DURING THE DAY...PRESUMABLY
KEEPING PRECIP CHANCES QUITE MINIMAL.
LOOKING BEYOND THE OFFICIAL 7-DAY FORECAST PERIOD...THERE ARE
SUGGESTIONS THAT NEXT WEEKEND COULD HOLD OUR NEXT POTENTIALLY
DECENT PRECIP CHANCES...BUT PLENTY TO IRON OUT HERE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1027 PM CST THU JAN 31 2013
.DISCUSSION.../ISSUED AT 1025 PM CST/
CURRENTLY CLEAR AND COLD OVER MUCH OF THE CWA. HOWEVER A MID LEVEL
CLOUD DECK IS APPROACHING QUICKER THAN EXPECTED FROM THE
WEST...FOCUSED AROUND 700 MB. RAP SEEMS TO HAVE A DECENT HANDLE ON
THIS...AND EXPECT THESE CLOUDS TO CONTINUE TO PROGRESS TO THE EAST.
THEY MAY TEND TO SLOW DOWN AS THEY ENCROACH ON THE ARCTIC AIRMASS
OVERHEAD...BUT THINKING SKIES BECOME OVERCAST AT MITCHELL BY 9Z AND
SIOUX FALLS AND SIOUX CITY BY 12Z. LOW TEMPERATURES TONIGHT ARE
TRICKY. WINDS WILL CONTINUE TO DROP OFF AS HIGH PRESSURE PUSHES
THROUGH. HOWEVER THE LACK OF SNOW COVER OVER THE HEART OF THE CWA
SHOULD LIMIT RADIATIONAL COOLING. THUS DECIDED TO BUMP LOWS UP A
BIT ACROSS THE REGION. ALSO BUMPED THEM SOME ACROSS OUR NORTH WHERE
MODELS HAVE HAD A PRETTY SIGNIFICANT COLD BIAS DURING COLD
OUTBREAKS. SNOW COVER UP THERE IS OLDER AND NOT IDEAL FOR
COOLING...AND PLACES LIKE MARSHALL MAY NEVER SEE THEIR WINDS GO
QUITE LIGHT ENOUGH TO ALLOW FOR GREAT RADIATIONAL COOLING. IT WILL
BE INTERESTING TO SEE WHAT HAPPENS...BUT TEND TO THINK THE HEDGE UP
IN LOWS IS PROBABLY THE WAY TO GO. STILL LOOKS LIKE A LIGHT SNOW
POTENTIAL TOMORROW AFTERNOON AND EVENING. BEST LARGE SCALE FORCING
STAYS TO OUR SOUTH...WITH THE BEST MID LEVEL FRONTAL SIGNATURE TO
OUR NORTH. TEND TO THINK SOMETHING CLOSE TO THE 0Z NAM
VERIFIES...WITH THE BEST BAND OF FLUFFY SNOW AND ACCUMULATIONS OF AN
INCH OR TWO FOLLOWING THE MID LEVEL FRONT...ACROSS THE NORTHEAST
PART OF OUR CWA OR EVEN SLIGHTLY FURTHER NORTHEAST IN SOUTHWEST
MINNESOTA. STILL SHOULD SEE FLURRIES ACROSS THE REST OF THE CWA.
WILL NOT ADJUST POPS AT THIS TIME...BUT INSTEAD ALLOW MIDNIGHT SHIFT
TO REASSESS AND MAKE ANY NECESSARY ADJUSTMENTS. /CHENARD
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS WILL PREVAIL THROUGH MID-DAY FRIDAY AND WINDS WILL
DECREASE OVERNIGHT AS HIGH PRESSURE SETTLES ACROSS THE REGION. A
FAST MOVING SHORT WAVE WILL BRING A FEW HOUR PERIOD OF LIGHT SNOW
WITH MVFR CIGS FRIDAY...MAINLY MID AFTERNOON FOR THE HON/FSD/SUX TAF
SITES. A PERIOD OF IFR CONDITIONS ARE EXPECTED WITH THE HEAVIEST
PORTION OF THE SNOW BAND HOWEVER...WHICH IS EXPECTED TO SET UP
NORTHEAST OF A LINE APPROXIMATELY FROM KBKX TO KSPW. SOUTHERLY WINDS
FRIDAY WILL SHIFT NORTHWEST BEHIND THIS SHORT WAVE FRIDAY EVENING.
/AEB
&&
.PREVIOUS DISCUSSION.../ISSUED AT 328 PM CST/
THIN LAYER OF ICE CRYSTALS AROUND 2000 FT AGL SHOULD DISSIPATE
FAIRLY QUICKLY THIS EVENING GIVING WAY TO CLEAR SKIES. NORTHWEST
WINDS ARE EXPECTED TO DECREASE AS SURFACE HIGH PRESSURE BUILDS INTO
THE REGION. WINDS SHOULD GRADUALLY DECREASE AND BACK THROUGHOUT THE
NIGHT TAKING ON MORE OF A WEST TO SOUTHWESTERLY DIRECTION FRIDAY
MORNING. WINDS SHOULD REMAIN FAIRLY WEAK...ESPECIALLY ACROSS
SOUTHWEST MINNESOTA INTO NORTHWEST IOWA LEADING TO GREAT RADIATIVE
CONDITIONS. LACK OF SNOW COVER LIMITING POTENTIAL FOR RECORD LOWS
ACROSS THE AREA....BUT HAVE SIDED WITH COOLEST LOWS IN THE NORTH AND
EAST WHERE LINGERING SNOW COVER AND LACK OF WINDS WILL LEAD TO IDEAL
RADIATIVE CONDITIONS.
WARM AIR ADVECTION INCREASES ACROSS CENTRAL SOUTH DAKOTA AFTER 06Z
AND SPREADS EAST THROUGH THE DAY ON FRIDAY. WILL LIKELY SEE CLOUDS
INCREASE IN THE WARM AIR ADVECTION...CREATING THE POTENTIAL FOR
LIGHT SNOW AS THE TEMPERATURE PROFILE DRIFTS THROUGH THE DENDRITIC
LAYER. AREA IS LEFT IN THE RIGHT REAR OF EXITING JET
STREAK...POTENTIALLY GETTING SOME ADDITIONAL HELP IN GENERATING
PRECIPITATION. SNOWFALL AMOUNTS SHOULD BE LIGHT...TOTALING A HALF
AN INCH OR LESS IN MOST LOCATIONS. KEPT TEMPERATURES CLOSER TO
GUIDANCE THAN PREVIOUS FORECAST ESPECIALLY IN THE EAST WHERE HIGHS
WILL LIKELY BE LATE IN THE DAY.
FRIDAY NIGHT TO THURSDAY...QUIET WEATHER EXPECTED THROUGH MOST OF
THE EXTENDED FORECAST.
KEPT LINGERING SNOW IN THE EASTERN HALF OF THE CWA INTO FRIDAY NIGHT
AS SREF/NAM AND TO A LESSER EXTENT THE GFS DROP A SHWV ACROSS THE
AREA WITH SOME LOW QPF ASSOCIATED. AS THIS FEATURE MOVES EAST
DECREASED POPS AND WX INTO THE OVERNIGHT HOURS. TEMPS ON FRIDAY
NIGHT WONT BE NEARLY AS COLD AS THIS PAST WED/THURS WITH LOWS
RANGING FROM THE SINGLE DIGITS NORTHEAST TO AROUND 20 DEGREES
SOUTHWEST.
ON SATURDAY H5 RIDGING MOVES ACROSS THE INTERMOUNTAIN WEST AND
WILL HELP KICK OFF A WARMING TREND OVER THE WEEKEND AND INTO NEXT
WEEK. NORTHWEST FLOW WILL BE THE DOMINANT FEATURE THROUGH THE
EXTENDED. HIGH TEMPS WILL RANGE FROM THE UPPER 20S NORTHEAST TO
LOW 40S SOUTHWEST WITH THE ENTIRE CWA WARMING TO ABOVE FREEZING
FOR HIGHS BY WEDNESDAY. SEVERAL SHWVS EMBEDDED IN THE NW FLOW MOVE
THROUGH THE NORTHERN PLAINS THRU THE PD BUT WITH LIMITED MOISTURE
AND TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF DID NOT MENTION
POPS AFTER FRIDAY NIGHT. /SALLY
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ001-012-
020-021-031-032.
WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
IAZ002-003-013-014- 022.
MN...WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
MNZ071-072-080-081- 089-090-097-098.
NE...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ013-014.
SD...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR SDZ057-058-
063>071.
WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
SDZ038>040-052>056- 059>062.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1033 AM EST FRI FEB 1 2013
.UPDATE...
LAKE EFFECT SNOWSHOWERS WERE PERSISTING ACROSS MUCH OF
BERRIEN...WESTERN CASS AND NORTHERN ST JOE (IN) COUNTIES THIS
MORNING. VSBYS HAVE GENERALLY BEEN AROUND A MILE IN THE HEAVIER
BANDS THUS FAR. THE MORE FOCUSED BAND HAS BEEN REPLACED BY A MULTI
BAND CONFIGURATION WHICH WILL PERSIST INTO EARLY AFTERNOON.
NAM12/LOCAL WRF STILL SHIFT THE FLOW MORE SOUTHWESTERLY THIS
AFTERNOON IN ADVANCE OF THE NEXT WAVE. THIS SHOULD ALLOW THE BANDS
TO MIGRATE NORTH AND REFOCUS ACROSS MAINLY NORTHERN BERRIEN
COUNTY. WHILE SOME CONCERN EXISTS EXACTLY WHERE THESE BANDS WILL
ORIENT IN RELATION TO THE CWA...THREAT WARRANTED A EXTENSION OF
SOME OF THE HEADLINES INTO THIS AFTERNOON. THE ADVISORY FOR ST JOE
MICHIGAN WAS ALLOWED TO EXPIRE WITH ACTIVITY REMAINING WEST OF THE
COUNTY. THE LAKE EFFECT SNOW WARNING/ADVISORY WAS EXTENDED THROUGH 18Z
IN CASS AND ST JOE RESPECTIVELY. THE WARNING WAS EXTENDED TO 21Z IN
BERRIEN COUNTY. WILL REEVALUATE HOW THINGS LOOK IN A FEW HOURS.
WIND CHILLS REMAINED IN THE 12 TO 15 BELOW ZERO RANGE ACROSS MOST
LOCATIONS. CLOSE ENOUGH TO ALLOW WIND CHILL ADVISORY TO REMAIN IN
PLACE TILL 18Z.
&&
.PREV DISCUSSION... /ISSUED 428 AM EST FRI FEB 1 2013/
..BITTERLY COLD THIS MORNING...
SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
AVIATION...
OUTSIDE CONTG LK EFFECT VCNTY KSBN TERMINAL FEW CONCERNS AS ARCTIC
WEDGE DEEPENS FURTHER SHRT TERM. THUS OUTSIDE PD OF IFR CONDS IN
-SHSN AT KSBN XPC CONTD DRYING AND BACKING LL WINDS BY MID MORNING
WILL SHIFT WHATS LEFT OF SNOW BANDS NWD INTO SRN MI W/VFR CONDS.
OTRWS STG GRADIENT FLW WILL CONT W/SFC WIND GUSTS AOA 20KTS
THROUGH THIS MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
INZ003>006-008-009-012>018-020-022>027-032>034.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
INZ004.
MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MIZ077.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ078.
OH...WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ015-016-
024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1008 AM EST FRI FEB 1 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 942 AM EST FRI FEB 1 2013
HIGH PRESSURE OVER THE CENTRAL MISSISSIPPI RIVER VALLEY WAS
BUILDING ACROSS THE OHIO VALLEY LATE THIS MORNING. SURFACE
ANALYSIS SHOWS GOOD PRESSURE GRADIENT ACROSS CENTRAL INDIANA AND
WINDS REMAINED RATHER GUSTY THIS MORNING. WIND CHILL VALUES
CONTINUE TO TOUCH WIND CHILL ADVISORY LEVELS AT TIMES...BUT WITH
DAYTIME HEATING EXPECTED VALUES TO RISE ABOVE ADVISORY LEVELS IN
THE NEXT HOUR AND WILL HOLD ON TO ADVISORY UNTIL THEN.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/...
ISSUED AT 906 AM EST FRI FEB 1 2013
MAIN AREA OF MVFR CEILINGS HAS BROKEN UP LEAVING BEHIND JUST PATCHY
MVFR CEILINGS. THUS HAVE CHANGED CEILINGS TO SCATTERED TEMPO BROKEN
FOR THE FIRST COUPLE OF HOURS. IT NOW APPEARS THAT VFR CONDITIONS
WILL BE PREDOMINANT FROM LATE MORNING ON.
PREVIOUS DISCUSSION FOLLOWS...
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...PUMA
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF/50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
906 AM EST FRI FEB 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
WILL BE ISSUING A WIND CHILL ADVISORY FOR AREAS ROUGHLY NORTH OF
INTERSTATE 70 UNTIL 011600Z AS IT APPEARS EXPECTED TEMPERATURES AND
WINDS THROUGH LATE MORNING WILL RESULT IN WIND CHILLS AROUND
ADVISORY CRITERIA. WINDS SHOULD BEGIN TO SLACKEN OFF TOWARDS MIDDAY
AS PRESSURE GRADIENT AND COLD ADVECTION DIMINISH...SO EXPECTING WIND
CHILLS TO IMPROVE BY THEN.
OTHERWISE...LOW LEVEL LAPSE RATES REMAIN STEEP UNDER STRONG COLD
ADVECTION THIS MORNING...SO WILL KEEP SOME FLURRIES IN THE FORECAST
THROUGH THE LATE MORNING. SHOULD SEE A DECREASING TREND IN CLOUD
COVER DURING THE DAY AS COLD ADVECTION/LOW LEVEL LAPSE RATES
DIMINISH LATER TODAY.
BASED ON PROGGED LOW LEVEL THICKNESSES TODAY...WILL TAKE ABOUT 3
DEGREES OFF THE NAM MOS GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/...
ISSUED AT 906 AM EST FRI FEB 1 2013
MAIN AREA OF MVFR CEILINGS HAS BROKEN UP LEAVING BEHIND JUST PATCHY
MVFR CEILINGS. THUS HAVE CHANGED CEILINGS TO SCATTERED TEMPO BROKEN
FOR THE FIRST COUPLE OF HOURS. IT NOW APPEARS THAT VFR CONDITIONS
WILL BE PREDOMINANT FROM LATE MORNING ON.
PREVIOUS DISCUSSION FOLLOWS...
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF/50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
536 AM EST FRI FEB 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
WILL BE ISSUING A WIND CHILL ADVISORY FOR AREAS ROUGHLY NORTH OF
INTERSTATE 70 UNTIL 011600Z AS IT APPEARS EXPECTED TEMPERATURES AND
WINDS THROUGH LATE MORNING WILL RESULT IN WIND CHILLS AROUND
ADVISORY CRITERIA. WINDS SHOULD BEGIN TO SLACKEN OFF TOWARDS MIDDAY
AS PRESSURE GRADIENT AND COLD ADVECTION DIMINISH...SO EXPECTING WIND
CHILLS TO IMPROVE BY THEN.
OTHERWISE...LOW LEVEL LAPSE RATES REMAIN STEEP UNDER STRONG COLD
ADVECTION THIS MORNING...SO WILL KEEP SOME FLURRIES IN THE FORECAST
THROUGH THE LATE MORNING. SHOULD SEE A DECREASING TREND IN CLOUD
COVER DURING THE DAY AS COLD ADVECTION/LOW LEVEL LAPSE RATES
DIMINISH LATER TODAY.
BASED ON PROGGED LOW LEVEL THICKNESSES TODAY...WILL TAKE ABOUT 3
DEGREES OFF THE NAM MOS GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011200Z TAF ISSUANCE/...
ISSUED AT 528 AM EST FRI FEB 1 2013
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
720 AM EST FRI FEB 1 2013
.SYNOPSIS...
ISSUED AT 339 AM EST FRI FEB 1 2013
AFTER MORNING SNOWS TODAY...THE SNOW SHOWERS ARE EXPECTED TO DIMINISH
SOMEWHAT THIS AFTERNOON. HOWEVER THE SNOW IS EXPECTED TO INCREASE
IN COVERAGE AND INTENSITY ONCE AGAIN BY THIS EVENING. SEVERAL
INCHES OF SNOW WILL BE POSSIBLE AGAIN TONIGHT...ESPECIALLY WEST OF
U.S. 131 AND NORTH OF HOLLAND. THE SNOW INTENSITY WILL BE HEAVY
ENOUGH TO OCCASIONALLY PRODUCE NEAR WHITEOUT CONDITIONS.
MEANWHILE INLAND AREAS SHOULD ALSO SEE SNOWFALL TONIGHT...WITH
SOMEWHAT LESS ACCUMULATION.
THE SNOW INTENSITY AND COVERAGE IS EXPECTED TO DIMINISH BY
SATURDAY AFTERNOON. THEN ANOTHER WEAKER SYSTEM MOVES IN FOR SUNDAY
MORNING...LIKELY PRODUCING MORE ACCUMULATING SNOW.
&&
.UPDATE...
ISSUED AT 658 AM EST FRI FEB 1 2013
BASED ON THE LATEST RADAR LOOPS IN CONJUNCTION WITH THE LATEST HRRR
AND RAP DATA.... I INCREASED THE POP CONDITIONAL NEAR AND WEST OF
US-131 THROUGH LATE MORNING. BOUNDARY LAYER WINDS BECOME MORE
WESTERLY DURING THE DAY TODAY SO THE SNOW BANDS WILL BECOME MORE
EAST / WEST. I DO EXPECT AN INCH OR TWO BETWEEN NOW AND NOON SOUTH
OF MUSKEGON AND WEST OF GRAND RAPIDS.
DAY TIME HEATING WILL HELP TO SPREAD THE SNOW SHOWERS INLAND BUT
THE INTENSITY SHOULD BE NOT MUCH MORE THAN FLURRIES EAST OF
US-131. I INCREASED POP THERE TOO SINCE MORE THAN LIKELY THERE
WILL BE SOME SNOW SHOWERS EVEN IF THEY ARE LIGHT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL ADJUST HEADLINES FOR THIS LONG DURATION EVENT.
WE WILL CONTINUE TO SEE FAIRLY INTENSE SNOW SHOWERS THIS MORNING
AS INVERSION HEIGHTS REMAIN HIGH AND THERE REMAINS LIFT WITHIN THE
DGZ. HOWEVER TOWARD MID DAY THE INVERSION HEIGHTS LOWER AND THERE
WILL BE LESS LIFT AS A SHORT WAVE EXITS THE REGION. THIS LULL WILL
PROBABLY ONLY LAST 6 TO 8 HOURS...SO NOT REALLY LONG ENOUGH TO
CALL THE EVENT OVER...AS THE SNOW WILL CONTINUE...JUST AT A LESS
INTENSE PACE.
THEN BY THIS EVENING THE SNOW COVERAGE AND INTENSITY WILL INCREASE
AGAIN AS ANOTHER NORTHERN STREAM SYSTEM MOVES IN. AHEAD OF THIS
SYSTEM THE FLOW WILL SWING AROUND TO THE WSW AND THE BEST LAKE
ENHANCED SNOWS SHOULD OCCUR WEST OF U.S. 131 AND NORTH OF HOLLAND.
THIS FLOW COULD ALSO PRODUCE A CONVERGENCE ZONE SOMEWHERE NEAR I-96
WITH THE COLD AIR WRAPPING AROUND THE SOUTHERN END OF THE LAKE. THE
SNOW WILL ALSO SPREAD FURTHER INLAND WITH THE SYNOPTIC ELEMENT
TONIGHT.
BY SATURDAY MORNING...BEHIND THIS SYSTEM...THE WINDS TURN BACK TO
THE NW AND SHOULD SHIFT THE LAKE ENHANCED FOCUS TO THE THE SW CORNER
OF THE CWA. THE I-96 CONVERGENCE BAND COULD LAST INTO SATURDAY
MORNING...THEN DIMINISH. ALL SNOW SHOWERS ARE EXPECTED TO FINALLY
DIMINISH INTO SATURDAY AFTERNOON AS INVERSION HEIGHTS LOWER.
THEREFORE FOR HEADLINES...HAVE DECIDED TO EXTEND THE LAKE EFFECT
SNOW WARNING FOR MUCH OF THE SW HALF OF THE CWA...ROUGHLY FROM
MBL-Y70-BTL FOR TODAY THROUGH TONIGHT. AGAIN...EXPECT A LULL IN THE
SNOWFALL INTENSITY THIS AFTERNOON...WITH A RAPID RAMP UP RETURNING
THIS EVENING. WILL CANCEL THE ADVISORY FURTHER INLAND FOR TODAY AS
ANY ACCUMS SHOULD BE MINIMAL. THEN WILL HAVE A NEW ADVISORY FOR
TONIGHT FOR ALL BUT THE NE COUNTIES AS THE SNOW REDEVELOPS. MOST OF
THE HEADLINES WILL END BY SATURDAY MORNING...HOWEVER WILL KEEP THE
SW CORNER OF THE CWA COVERED WITH WARNING THROUGH 18Z SAT WITH THE
NW FLOW ENHANCEMENT CAUSING LINGERING SNOWS.
WESTERLY WINDS WILL CONTINUE TO CAUSE DRIFTING SNOW TODAY AND
TONIGHT TO ADD TO THE IMPACTS. THE WINDS SHOULD FINALLY SUBSIDE
LATE TONIGHT AND REMAIN FAIRLY LIGHT INTO SATURDAY.
ANOTHER SPIKE IN THE SNOW ACTIVITY IS EXPECTED LATE SATURDAY
NIGHT/SUNDAY MORNING WITH ANOTHER SHORT WAVE. HOWEVER AT THIS POINT
IT LOOKS TO BE A QUICKER HITTING SYSTEM.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
THE OVERALL PATTERN FEATURES CLIPPER SYSTEMS ROTATING AROUND
THE SOUTHERN EDGE OF THE POLAR VORTEX THROUGH TUESDAY. THAT WILL
KEEP SOUTHWEST MICHIGAN WITH BELOW NORMAL TEMPERATURES AND SNOW EACH
DAY. NO MAJOR STORMS ARE EXPECTED BUT LOCALLY SIGNIFICANT LAKE
EFFECT SNOW IS POSSIBLE INTO TUESDAY.
AS THAT POWERHOUSE EAST ASIAN JET BREAKS THROUGH THE WESTERN UPPER
RIDGE IN THE TUESDAY TIME FRAME... THE POLAR VORTEX WILL BE SHIFTED
NORTHWARD FARTHER NORTH INTO CANADA. THAT WILL ALLOW FOR A BREAK IN
THE SNOWY AND COLD WEATHER PATTERN WE HAVE HAD IN SOUTHWEST MICHIGAN
DURING THE MID TO LATE WEEK TIME FRAME. IT SHOULD BE NOTED THAT FOR
THE PAST 4 NIGHTS... EACH RUN OF THE GFS AND ECMWF HAS BEEN COOLER
AT THE LONGER RANGES. CURRENTLY SURFACE TEMPERATURES MAY NOT GET
ABOVE FREEZING OVER MOST OF THE CWA UNTIL THE WEEKEND OF THE 8TH OF
FEBRUARY.
THE MONDAY SYSTEM... WHICH 4 DAYS AGO WAS FORECAST OVER LAKE
SUPERIOR... IS NOW FORECAST TO TRACK SOUTH OF LAKE MICHIGAN DURING
MONDAY AFTERNOON. THIS SHOULD BRING A TRACK OF LIGHT SNOW OVER THE
SOUTHERN AND CENTRAL CWA.
NEXT IN LINE IS A SYSTEM THAT TRACKS FROM CENTRAL BRITISH COLUMBIA
MONDAY TO SOUTHERN LAKE MICHIGAN BY TUESDAY AFTERNOON. WITH COLDER
AIR IN PLACE (LATEST MODEL ROUND ARE COLDER) COULD BE ANOTHER
SOUTHWEST FLOW SNOW EVENT. MOST OF THE CWA WOULD GET 1 TO 3 INCHES
OTHERWISE FROM THIS ONE.
HIGH PRESSURE AIDED BY THE POLAR JET BEING OVER MICHIGAN SHOULD
LARGELY KILL THE LAKE EFFECT SNOW MACHINE. THAT WILL BE FOLLOWED BY
A MORE SOUTHERN STREAM SYSTEM THURSDAY OR LATER WITH A WARMING TREND
BEING NOTED.
BOTTOM LINE... SNOW AND COLD INTO TUESDAY THEN A WARMING TREND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EST FRI FEB 1 2013
SNOW SHOWERS WILL DECREASE IN INTENSITY BUT NOT END THIS AFTERNOON
AS MID LEVEL RIDGING LOWERS INVERSION HEIGHTS. WINDS IN THE
BOUNDARY LAYER WILL BECOME MORE WESTRLY BY THIS AFTERNOON SO SNOW
BANDS WILL BE MORE WEST TO EAST. ALL BUT THE LAN TAF SITE HAVE IFR
CONDITIONS THIS MORNING. THAT MAY IMPROVE TO MVFR THIS AFTERNOON
BEFORE THE NEXT SYSTEM BRINGS SOLID IFR/LIFR CONDITIONS IN SNOW
BACK TO THE AREA BY MIDNIGHT.
&&
.MARINE...
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL REPLACE THE GALE WARNING WITH A SMALL CRAFT ADVISORY AS
WESTERLY WINDS SLOWLY DIMINISH.
&&
.HYDROLOGY...
ISSUED AT 339 AM EST FRI FEB 1 2013
LITTLE CHANGE TO THE OVERALL HYDRO SITUATION. THE ICE JAM NEAR
ROGERS HEIGHTS CONTINUES TO WARRANT A FLOOD WARNING. THE WHITE
RIVER IN WHITEHALL REMAINS OUT OF IT/S BANKS...ALTHOUGH THE CREST
HAS ALREADY OCCURRED AND CONDITIONS SHOULD IMPROVE BY THIS EVENING.
SEVERAL OTHER RIVERS ARE IMPACTING LOW LAYING AREAS WHERE ADVISORIES
HAVE BEEN ISSUED. OVERALL CRESTS HAVE OCCURRED OR WILL OCCUR WITHIN
THE 24 HOURS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR MIZ056-057-
064-065-071-072.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
044-050-058-066-073.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR MIZ038-045-051-059-067-074.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST SATURDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
612 AM EST FRI FEB 1 2013
.AVIATION...
//DISCUSSION...
THE DRY MIDLEVEL AIR MAKING INROADS ACROSS SOUTHEASTERN MICHIGAN
THIS MORNING HAS BEEN SUCCESSFUL IN WEAKENING THE SNOW SHOWER
ACTIVITY. MODEL SOUNDINGS SHOW THAT LAPSE RATES WILL BE STEEP ENOUGH
IN THE LOWEST FEW THOUSAND FEET TO SUPPORT FLURRIES AND LIGHT SNOW
SHOWERS TODAY. HOWEVER...DEPTH OF LOWER STABILITY WILL BE
DRAMATICALLY LESS THAN YESTERDAY SO BEHAVIOR/VIGOR OF TODAYS
ACTIVITY WILL BE MARKEDLY LESS. A BUILDING SURFACE RIDGE WILL CAUSE
WIND DIRECTIONS TO VEER WESTERLY TO SOUTHWESTERLY DURING THE DAY.
FOR DTW...THE CONCENTRATED BAND OF SNOW SHOWERS HAS WEAKENED
DRAMATICALLY OVERNIGHT. THE CURRENT AXIS IS IMMEDIATELY SOUTH AND
WEST OF THE TERMINAL THIS MORNING. THE POTENTIAL EXISTS FOR
INDIVIDUAL CONVECTIVE ELEMENTS TO BRUSH THE TERMINAL FOR A FEW HOURS
THIS MORNING BEFORE MIGRATING NORTHWARD.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT THROUGH THE TAF
PERIOD.
&&
.PREV DISCUSSION...ISSUED 352 AM EST FRI FEB 1 2013
SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
534 AM CST FRI FEB 1 2013
.AVIATION...
FOR THE NORTH PLATTE AND VALENTINE TERMINALS THROUGH 12Z SATURDAY.
EXPECT MOSTLY CLOUDY SKIES TODAY AND TONIGHT ACROSS MOST OF WESTERN
AND NORTH CENTRAL NEBRASKA...WITH ABUNDANT MID AND HIGH LEVEL
CLOUDINESS EXPECTED TODAY...AND LOW TO MID LEVEL CLOUD COVER
POSSIBLE TONIGHT. AN UPPER LEVEL DISTURBANCE WILL TRACK FROM THE
DAKOTAS INTO NORTHERN AND EASTERN NEBRASKA THIS AFTERNOON AND EVENING. AS
THIS FEATURE APPROACHES...ABUNDANT MID LEVEL CLOUDINESS WILL DEVELOP
THIS AFTERNOON. CIGS WILL POSSIBLY LOWER TO MVFR LEVELS AT THE KVTN
TERMINAL EARLY THIS EVENING. IN ADDITION...LIGHT SNOW IS POSSIBLE
FRIDAY EVENING...ESPECIALLY OVER NORTHERN NEBRASKA. VSBYS DOWN TO 3
TO 5 SM ARE POSSIBLE IN ANY AREAS OF LIGHT SNOW...ESPECIALLY AT THE
KVTN TERMINAL. FURTHER SOUTH AT THE KLBF TERMINAL...MID LEVEL LIFT
IS VERY WEAK SO THE THREAT FOR SNOW IS EXPECTED TO BE MINIMAL.
ACROSS NORTHERN NEBRASKA...LIGHT SNOW AND MVFR CIGS WILL END
OVERNIGHT...HOWEVER...OVERCAST VFR SKIES WILL CONTINUE INTO SATURDAY
MORNING.
&&
.PREV DISCUSSION... /ISSUED 348 AM CST THU JAN 31 2013/
DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
949 AM CST FRI FEB 1 2013
.DISCUSSION...
BUMPED UP POPS FOR THE REST OF THE DAY. OBS AT VALLEY CITY AND
COOPERSTOWN SHOW SNOW HAS ALREADY STARTED TO MOVE INTO THE
SOUTHWESTERN COUNTIES...AND WEB CAMS CONFIRM SOME LIGHT SNOW
BEGINNING TO FALL. RAP AND NAM ARE IN PRETTY GOOD AGREEMENT ON
THIS SNOW BAND MOVING INTO OUR SOUTHEASTERN COUNTIES BY THIS
AFTERNOON. VIS HAVE NOT GONE TERRIBLY LOW SO THINK THAT ANY
ACCUMULATIONS WILL BE VERY LIGHT AND REMAIN UNDER AN INCH. SNOW
WILL BEGIN TO TAPER OFF BY THIS EVENING.
AS FOR TEMPERATURES/WIND CHILLS...ADJUSTED HOURLY TEMPS AS
READINGS IN THE WEST HAVE STARTED TO RISE A BIT FASTER THAN
EXPECTED. WITH SOUTHERLY WINDS KICKING IN THE WESTERN COUNTIES
SHOULD SEE SOME TEMPS GOING UP ABOVE ZERO BY THIS AFTERNOON. A FEW
OF THE WIND CHILLS THIS MORNING IN ISOLATED SPOTS HAVE BEEN AROUND
40 BELOW...BUT THE BITTER COLD WILL BE VERY SHORT LIVED AS TEMPS
BEGIN TO RISE SO WILL JUST KEEP THE ADVISORY AS GOING. WILL HAVE
TO WATCH IN CASE TEMPS ARE SLOWER TO RISE THAN EXPECTED...BUT FOR
NOW PLAN ON LETTING THE WIND CHILL ADVISORY EXPIRE ON TIME AT 18Z.
&&
.AVIATION...
LOW VFR DECK MOVING SOUTHEASTWARD FROM CENTRAL ND TO REACH KFAR LATE
MORNING...TRENDING TO MVFR CIGS AT VALLEY SITES THIS
AFTERNOON...REACHING KBJI THIS EVENING. -SN MOST LIKELY RESTRICTED
TO KFAR ARRIVING EARLY AFTERNOON. LIGHT SOUTH TO SOUTHWEST WINDS
WILL SHIFT TO NORTHWEST LATER TODAY KDVL AND TONIGHT AT OTHER
LOCATIONS.
&&
.PREV DISCUSSION... /ISSUED 430 AM CST FRI FEB 1 2013/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
UPPER LEVEL RIDGE WAS LOCATED OVER THE WESTERN NORTH AMERICA AND A
TROUGH WAS LOCATED OVER EASTERN CANADA AND THE NORTHEAST US. UPPER
AIR PATTERN DEAMPLIFIES THIS PERIOD. GFS IS A LITTLE FASTER THAN THE
ECMWF. WILL PREFER THE GFS. WATER VAPOR LOOP INDICATED A SHORT WAVE
OVER MT. SHORT WAVE WILL MOVE ACROSS SD AND NE THIS AFTERNOON AND
TONIGHT.
THERMAL BOUNDARY WILL REMAIN ACROSS THE FORECAST AREA THROUGH MUCH
OF THE PERIOD. SHORT WAVES WILL MOVE THROUGH THE FLOW AND PRODUCE
PERIODS OF LIGHT SNOW. WILL SPEED UP PRECIP MOVING INTO THE AREA
THIS AFTERNOON AND SLOW IT DOWN FOR TONIGHT. RESPECTABLE SHORT WAVE
MOVES THROUGH SAT AND SAT EVENING AND A BETTER CHANCE FOR SNOW. GFS
AND ECMWF HAVE BEEN SHIFTING PRECIP FARTHER WEST WITH EACH RUN. SO
WILL SHIFT PRECIP FARTHER WEST SUN NIGHT. ALSO WILL LOWER TEMPS FOR
SAT AND SUN.
WIND CHILLS OVER THE WESTERN ZONES HAVE TEMPERED MOSTLY TO WIND
CHILL CRITERIA AND SO HAVE REPLACED WIND CHILL WARNING WITH WIND
CHILL ADVISORY THROUGH NOON TODAY.
LONG TERM...MONDAY THROUGH THURSDAY NIGHT
00 UTC GFS/ECMWF IN GOOD AGREEMENT NEXT WEEK...BOTH SHOWING A COUPLE
CLIPPER SYSTEMS MOVING ACROSS THE NORTHERN PLAINS IN NORTHWEST FLOW
ALOFT. THE FIRST WAVE MOVES THROUGH MONDAY NIGHT AND THE SECOND
WEDNESDAY NIGHT. BEST CHANCE FOR MEASURABLE SNOW WILL BE MONDAY AND
MONDAY NIGHT FROM THE DEVILS LAKE BASIN INTO NORTHWEST MN AS A
WELL-DEFINED BAROCLINIC ZONE SETS-UP ACROSS THE FORECAST AREA.
STRONG 850 HPA WARM AIR ADVECTION...COMBINED WITH THE LEFT-EXIT
REGION OF A 125 KT 300 HPA JET STREAK AND SURFACE MIXING RATIOS
AROUND 2 G/KG SHOULD RESULT IN AT LEAST A FEW INCHES ACCUMULATION.
DYNAMIC SUPPORT FOR WEDNESDAY NIGHT/S WAVE NOT AS IMPRESSIVE...SO
WILL KEEP POPS MAINLY IN THE 20S.
SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT MONDAY/TUESDAY WILL
RESULT IN DAYTIME HIGHS FROM THE LOW 20S ACROSS SOUTHEAST ND TO THE
LOW TO MID TEENS ACROSS THE LAKE OF THE WOODS. THERMAL PROFILE
INCREASES WEDNESDAY/THURSDAY AS WEST COAST RIDGE MOVES OVERHEAD...
SO EXPECT HIGHS IN THE LOW TO MID 20S REGION-WIDE. AFTER MONDAY
MORNING...NIGHTTIME LOWS SHOULD REMAIN ABOVE ZERO THROUGH THE
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
JR/WJB
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
100 PM EST FRI FEB 1 2013
.UPDATE...
ONLY MINOR ADJUSTMENTS NEEDED TO WX/POPS AS TRENDS HAVE UNFOLDED
AS EXPECTED. LAKE EFFECT BANDS HAVE QUICKLY SHIFTED NORTH AND ARE
NOW ORIENTED SW-NE ACROSS MUCH OF BERRIEN COUNTY AND EXTREME NW
CASS COUNTY. ADVISORY IN ST JOE AND WARNING IN CASS COUNTY WILL BE
ALLOWED TO EXPIRE WITH RE EVALUATION OF BERRIEN COUNTY WARNING
WITH AFTERNOON PACKAGE.
TEMPERATURES HAVE CLIMBED AOA 10 DEGREES IN ALL BUT A FEW
LOCATIONS. THIS HAS ALSO ALLOWED WIND CHILLS TO "WARM" SOME...AWAY
FROM ADVISORY CRITERIA. AS A RESULT...THE WIND CHILL ADVISORY WILL
ALSO BE ALLOWED TO EXPIRE. WILL NEED TO MAKE SOME CHANGES TO
ACTUAL TEMP TRENDS AS SOME LOCATIONS ALREADY ABOVE FORECASTED
HIGHS. DON`T THINK MUCH MORE OF A RISE WILL OCCUR WITH SC FORMING
IN SEVERAL LOCATIONS THAT WILL SLOW DOWN/STOP ANY ADDITIONAL
CLIMB.
&&
.AVIATION...
MVFR CIGS TO PREVAIL AT BOTH SITES INTO LATE AFTERNOON AS SC DECK
EXPANDS ACROSS THE AREA. WILL NEED TO WATCH TRENDS WITH SOME
POTENTIAL FOR FLURRIES/LGT SNOW SHOWERS REDEVELOPING BUT THINK
OVERALL IMPACT TO TAFS SHOULD BE MINIMAL. LATER TONIGHT...CLIPPER
SYSTEM WILL ARRIVE AND LIGHT SNOW WILL OVERSPREAD THE AREA BETWEEN
8 AND 10Z. HAVE LEFT THE BROAD BRUSHED 2 TO 3 SM AT BOTH SITES
LATER TONIGHT THROUGH18Z WITH MODELS AGREEING ON SNOW LINGERING
UNTIL CLOSE TO THE END OF THE PERIOD. POTENTIAL EXISTS AT BOTH
SITES FOR VSBYS TO DROP TO A MILE OR LESS AT TIMES IN POCKETS OF
HEAVIER SNOWFALL. HOWEVER CONFIDENCE OF PROBS OF IMPACT AT EITHER
SITE LOW SO WILL NOT ADD ANY NEW GROUPS.
&&
.PREV DISCUSSION... /ISSUED 1033 AM EST FRI FEB 1 2013/
UPDATE...
LAKE EFFECT SNOWSHOWERS WERE PERSISTING ACROSS MUCH OF
BERRIEN...WESTERN CASS AND NORTHERN ST JOE (IN) COUNTIES THIS
MORNING. VSBYS HAVE GENERALLY BEEN AROUND A MILE IN THE HEAVIER
BANDS THUS FAR. THE MORE FOCUSED BAND HAS BEEN REPLACED BY A MULTI
BAND CONFIGURATION WHICH WILL PERSIST INTO EARLY AFTERNOON.
NAM12/LOCAL WRF STILL SHIFT THE FLOW MORE SOUTHWESTERLY THIS
AFTERNOON IN ADVANCE OF THE NEXT WAVE. THIS SHOULD ALLOW THE BANDS
TO MIGRATE NORTH AND REFOCUS ACROSS MAINLY NORTHERN BERRIEN
COUNTY. WHILE SOME CONCERN EXISTS EXACTLY WHERE THESE BANDS WILL
ORIENT IN RELATION TO THE CWA...THREAT WARRANTED A EXTENSION OF
SOME OF THE HEADLINES INTO THIS AFTERNOON. THE ADVISORY FOR ST JOE
MICHIGAN WAS ALLOWED TO EXPIRE WITH ACTIVITY REMAINING WEST OF THE
COUNTY. THE LAKE EFFECT SNOW WARNING/ADVISORY WAS EXTENDED THROUGH 18Z
IN CASS AND ST JOE RESPECTIVELY. THE WARNING WAS EXTENDED TO 21Z IN
BERRIEN COUNTY. WILL REEVALUATE HOW THINGS LOOK IN A FEW HOURS.
WIND CHILLS REMAINED IN THE 12 TO 15 BELOW ZERO RANGE ACROSS MOST
LOCATIONS. CLOSE ENOUGH TO ALLOW WIND CHILL ADVISORY TO REMAIN IN
PLACE TILL 18Z.
PREV DISCUSSION... /ISSUED 428 AM EST FRI FEB 1 2013/
.BITTERLY COLD THIS MORNING...
SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE
MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MIZ077.
OH...NONE
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1247 PM EST FRI FEB 1 2013
.SYNOPSIS...
ISSUED AT 339 AM EST FRI FEB 1 2013
AFTER MORNING SNOWS TODAY...THE SNOW SHOWERS ARE EXPECTED TO DIMINISH
SOMEWHAT THIS AFTERNOON. HOWEVER THE SNOW IS EXPECTED TO INCREASE
IN COVERAGE AND INTENSITY ONCE AGAIN BY THIS EVENING. SEVERAL
INCHES OF SNOW WILL BE POSSIBLE AGAIN TONIGHT...ESPECIALLY WEST OF
U.S. 131 AND NORTH OF HOLLAND. THE SNOW INTENSITY WILL BE HEAVY
ENOUGH TO OCCASIONALLY PRODUCE NEAR WHITEOUT CONDITIONS.
MEANWHILE INLAND AREAS SHOULD ALSO SEE SNOWFALL TONIGHT...WITH
SOMEWHAT LESS ACCUMULATION.
THE SNOW INTENSITY AND COVERAGE IS EXPECTED TO DIMINISH BY
SATURDAY AFTERNOON. THEN ANOTHER WEAKER SYSTEM MOVES IN FOR SUNDAY
MORNING...LIKELY PRODUCING MORE ACCUMULATING SNOW.
&&
.UPDATE...
ISSUED AT 658 AM EST FRI FEB 1 2013
BASED ON THE LATEST RADAR LOOPS IN CONJUNCTION WITH THE LATEST HRRR
AND RAP DATA.... I INCREASED THE POP CONDITIONAL NEAR AND WEST OF
US-131 THROUGH LATE MORNING. BOUNDARY LAYER WINDS BECOME MORE
WESTERLY DURING THE DAY TODAY SO THE SNOW BANDS WILL BECOME MORE
EAST / WEST. I DO EXPECT AN INCH OR TWO BETWEEN NOW AND NOON SOUTH
OF MUSKEGON AND WEST OF GRAND RAPIDS.
DAY TIME HEATING WILL HELP TO SPREAD THE SNOW SHOWERS INLAND BUT
THE INTENSITY SHOULD BE NOT MUCH MORE THAN FLURRIES EAST OF
US-131. I INCREASED POP THERE TOO SINCE MORE THAN LIKELY THERE
WILL BE SOME SNOW SHOWERS EVEN IF THEY ARE LIGHT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL ADJUST HEADLINES FOR THIS LONG DURATION EVENT.
WE WILL CONTINUE TO SEE FAIRLY INTENSE SNOW SHOWERS THIS MORNING
AS INVERSION HEIGHTS REMAIN HIGH AND THERE REMAINS LIFT WITHIN THE
DGZ. HOWEVER TOWARD MID DAY THE INVERSION HEIGHTS LOWER AND THERE
WILL BE LESS LIFT AS A SHORT WAVE EXITS THE REGION. THIS LULL WILL
PROBABLY ONLY LAST 6 TO 8 HOURS...SO NOT REALLY LONG ENOUGH TO
CALL THE EVENT OVER...AS THE SNOW WILL CONTINUE...JUST AT A LESS
INTENSE PACE.
THEN BY THIS EVENING THE SNOW COVERAGE AND INTENSITY WILL INCREASE
AGAIN AS ANOTHER NORTHERN STREAM SYSTEM MOVES IN. AHEAD OF THIS
SYSTEM THE FLOW WILL SWING AROUND TO THE WSW AND THE BEST LAKE
ENHANCED SNOWS SHOULD OCCUR WEST OF U.S. 131 AND NORTH OF HOLLAND.
THIS FLOW COULD ALSO PRODUCE A CONVERGENCE ZONE SOMEWHERE NEAR I-96
WITH THE COLD AIR WRAPPING AROUND THE SOUTHERN END OF THE LAKE. THE
SNOW WILL ALSO SPREAD FURTHER INLAND WITH THE SYNOPTIC ELEMENT
TONIGHT.
BY SATURDAY MORNING...BEHIND THIS SYSTEM...THE WINDS TURN BACK TO
THE NW AND SHOULD SHIFT THE LAKE ENHANCED FOCUS TO THE THE SW CORNER
OF THE CWA. THE I-96 CONVERGENCE BAND COULD LAST INTO SATURDAY
MORNING...THEN DIMINISH. ALL SNOW SHOWERS ARE EXPECTED TO FINALLY
DIMINISH INTO SATURDAY AFTERNOON AS INVERSION HEIGHTS LOWER.
THEREFORE FOR HEADLINES...HAVE DECIDED TO EXTEND THE LAKE EFFECT
SNOW WARNING FOR MUCH OF THE SW HALF OF THE CWA...ROUGHLY FROM
MBL-Y70-BTL FOR TODAY THROUGH TONIGHT. AGAIN...EXPECT A LULL IN THE
SNOWFALL INTENSITY THIS AFTERNOON...WITH A RAPID RAMP UP RETURNING
THIS EVENING. WILL CANCEL THE ADVISORY FURTHER INLAND FOR TODAY AS
ANY ACCUMS SHOULD BE MINIMAL. THEN WILL HAVE A NEW ADVISORY FOR
TONIGHT FOR ALL BUT THE NE COUNTIES AS THE SNOW REDEVELOPS. MOST OF
THE HEADLINES WILL END BY SATURDAY MORNING...HOWEVER WILL KEEP THE
SW CORNER OF THE CWA COVERED WITH WARNING THROUGH 18Z SAT WITH THE
NW FLOW ENHANCEMENT CAUSING LINGERING SNOWS.
WESTERLY WINDS WILL CONTINUE TO CAUSE DRIFTING SNOW TODAY AND
TONIGHT TO ADD TO THE IMPACTS. THE WINDS SHOULD FINALLY SUBSIDE
LATE TONIGHT AND REMAIN FAIRLY LIGHT INTO SATURDAY.
ANOTHER SPIKE IN THE SNOW ACTIVITY IS EXPECTED LATE SATURDAY
NIGHT/SUNDAY MORNING WITH ANOTHER SHORT WAVE. HOWEVER AT THIS POINT
IT LOOKS TO BE A QUICKER HITTING SYSTEM.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
THE OVERALL PATTERN FEATURES CLIPPER SYSTEMS ROTATING AROUND
THE SOUTHERN EDGE OF THE POLAR VORTEX THROUGH TUESDAY. THAT WILL
KEEP SOUTHWEST MICHIGAN WITH BELOW NORMAL TEMPERATURES AND SNOW EACH
DAY. NO MAJOR STORMS ARE EXPECTED BUT LOCALLY SIGNIFICANT LAKE
EFFECT SNOW IS POSSIBLE INTO TUESDAY.
AS THAT POWERHOUSE EAST ASIAN JET BREAKS THROUGH THE WESTERN UPPER
RIDGE IN THE TUESDAY TIME FRAME... THE POLAR VORTEX WILL BE SHIFTED
NORTHWARD FARTHER NORTH INTO CANADA. THAT WILL ALLOW FOR A BREAK IN
THE SNOWY AND COLD WEATHER PATTERN WE HAVE HAD IN SOUTHWEST MICHIGAN
DURING THE MID TO LATE WEEK TIME FRAME. IT SHOULD BE NOTED THAT FOR
THE PAST 4 NIGHTS... EACH RUN OF THE GFS AND ECMWF HAS BEEN COOLER
AT THE LONGER RANGES. CURRENTLY SURFACE TEMPERATURES MAY NOT GET
ABOVE FREEZING OVER MOST OF THE CWA UNTIL THE WEEKEND OF THE 8TH OF
FEBRUARY.
THE MONDAY SYSTEM... WHICH 4 DAYS AGO WAS FORECAST OVER LAKE
SUPERIOR... IS NOW FORECAST TO TRACK SOUTH OF LAKE MICHIGAN DURING
MONDAY AFTERNOON. THIS SHOULD BRING A TRACK OF LIGHT SNOW OVER THE
SOUTHERN AND CENTRAL CWA.
NEXT IN LINE IS A SYSTEM THAT TRACKS FROM CENTRAL BRITISH COLUMBIA
MONDAY TO SOUTHERN LAKE MICHIGAN BY TUESDAY AFTERNOON. WITH COLDER
AIR IN PLACE (LATEST MODEL ROUND ARE COLDER) COULD BE ANOTHER
SOUTHWEST FLOW SNOW EVENT. MOST OF THE CWA WOULD GET 1 TO 3 INCHES
OTHERWISE FROM THIS ONE.
HIGH PRESSURE AIDED BY THE POLAR JET BEING OVER MICHIGAN SHOULD
LARGELY KILL THE LAKE EFFECT SNOW MACHINE. THAT WILL BE FOLLOWED BY
A MORE SOUTHERN STREAM SYSTEM THURSDAY OR LATER WITH A WARMING TREND
BEING NOTED.
BOTTOM LINE... SNOW AND COLD INTO TUESDAY THEN A WARMING TREND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1247 PM EST FRI FEB 1 2013
MAIN FOCUS WITH THE 18Z SET OF FCSTS WILL BE LAKE EFFECT TRENDS
TODAY AND THEN TRENDS LATE THIS EVENING INTO SAT MORNING WITH THE
WAVE OF LOW PRESSURE THAT WILL BE MOVING THROUGH.
LAKE EFFECT SNOW SHOWERS HAVE GENERALLY LOST A BIT OF INTENSITY
THIS MORNING AS SOME RIDGING MOVES IN TEMPORARILY. SOME LOCALIZED
HEAVIER SNOW SHOWERS ARE BRINGING VSBYS DOWN INTO THE LIFR
CATEGORY. WE SHOULD SEE THESE CONDITIONS BECOME LESS AND LESS
PREVALENT THROUGH THE AFTERNOON.
AS MENTIONED ABOVE...THE BREAK WILL BE SHORT LIVED. A WAVE OF LOW
PRESSURE WILL SLIDE IN ACROSS THE AREA TOWARD MIDNIGHT EST OR 05Z.
LIGHT SNOW WILL BREAK OUT AT ALL TERMINALS BY 07-08Z. IFR IS
LIKELY AT ALL THE SITES. KMKG AND KGRR HAVE A GOOD CHANCE OF
SEEING LIFR/VLIFR CONDITIONS AS WE ARE EXPECTING A HEAVIER LAKE
ENHANCED BAND FROM THE SW TO AFFECT THOSE AREAS. THE WAVE SHOULD
MOVE OUT LATE IN THE PERIOD...AND LEAVE SOME LIGHT LAKE EFFECT AND
IMPROVING CONDITIONS.
&&
.MARINE...
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL REPLACE THE GALE WARNING WITH A SMALL CRAFT ADVISORY AS
WESTERLY WINDS SLOWLY DIMINISH.
&&
.HYDROLOGY...
ISSUED AT 339 AM EST FRI FEB 1 2013
LITTLE CHANGE TO THE OVERALL HYDRO SITUATION. THE ICE JAM NEAR
ROGERS HEIGHTS CONTINUES TO WARRANT A FLOOD WARNING. THE WHITE
RIVER IN WHITEHALL REMAINS OUT OF IT/S BANKS...ALTHOUGH THE CREST
HAS ALREADY OCCURRED AND CONDITIONS SHOULD IMPROVE BY THIS EVENING.
SEVERAL OTHER RIVERS ARE IMPACTING LOW LAYING AREAS WHERE ADVISORIES
HAVE BEEN ISSUED. OVERALL CRESTS HAVE OCCURRED OR WILL OCCUR WITHIN
THE 24 HOURS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR MIZ056-057-
064-065-071-072.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
044-050-058-066-073.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR MIZ038-045-051-059-067-074.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST SATURDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1231 PM EST FRI FEB 1 2013
.AVIATION...
//DISCUSSION...
SOME LIGHT LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE THROUGH THE
EARLY PART OF THIS AFTERNOON. HOWEVER...WITH LOWER WIND SPEEDS AND
WINDS EVENTUALLY SHIFTING TO THE SOUTHWEST DUE TO A SURFACE RIDGE
BUILDING INTO THE AREA...SNOW SHOWERS WILL BE LESS INTENSE THAN
YESTERDAY. SNOW SHOWERS WILL SLOWLY DIMINISH BY LATE AFTERNOON. THE
NEXT CHANCE FOR IMPACTFUL SNOW WILL ARRIVE SATURDAY MORNING AS A
SHORTWAVE TRACKS JUST TO THE SOUTH OF MICHIGAN CLIPPING SOUTHERN
MICHIGAN. WHILE ALL TAF SITES HAVE SNOW IN THE FORECAST...THE
SOUTHERN TAF SITES /DTW...DET...YIP/ HAVE THE GREATEST CHANCE TO SEE
ACCUMULATING SNOW SATURDAY MORNING.
FOR DTW...BANDS OF SCATTERED SNOW SHOWERS WILL CONTINUE TO IMPACT
THE TERMINAL OVER THE NEXT FEW HOURS. SNOW SHOWERS WILL SLOWLY COME
TO AN END AS WINDS SHIFT SOUTHWEST AND LINGERING SNOW SHOWERS MOVE
NORTH AND DISSIPATE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT FOR MOST
OF THE TAF PERIOD.
&&
.PREV DISCUSSION...ISSUED 352 AM EST FRI FEB 1 2013
SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....RK
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1223 PM CST FRI FEB 1 2013
.AVIATION...
SURFACE WARM FRONT PUSHES EAST ACROSS THE AREA THIS
AFTERNOON...MEANWHILE A WEAK UPPER LEVEL DISTURBANCE SLIDES
SOUTHEAST ACROSS THE AREA. DRY LOW LEVELS SHOULD RESULT IN LITTLE
IF ANY PRECIP REACHING THE GROUND THIS AFTERNOON...HOWEVER DO
EXPECT AN INCREASE OF MID AND UPPER LEVEL CLOUDS. OVERNIGHT AS
TEMPS COOL A BETTER CHANCES INCREASE FOR PRECIP TO REACH THE
GROUND. TEMPS CLOSER TO FREEZING WITH A RAIN/SNOW MIX OR ALL LIGHT
SNOW EVENT ANTICIPATED. HAVE INCLUDED A TEMPO FOR SNOW FOR
KVTN...HOWEVER HAVE KEPT SNOW OUT OF KLBF DUE TO LACK OF
CONFIDENCE THE DRY LOWER LEVELS WILL BE OVERCOME WHERE LIFT IS
WEAKER. BY MORNING THE WAVE WILL EXIT WITH DECREASING CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 348 AM CST THU JAN 31 2013/
DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
335 PM EST FRI FEB 1 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND SATURDAY. ANOTHER
COLD FRONT WILL CROSS THE AREA SATURDAY NIGHT FOLLOWED BY HIGH PRESSURE
SUNDAY AND MONDAY. A COLD FRONT WILL APPROACH THE REGION TUESDAY AND
CROSS THE AREA TUESDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA
WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 315 PM FRIDAY...COLD AND VERY DRY AIRMASS CONTINUES TO TAKE
HOLD OVER EASTERN NORTH CAROLINA WITH MOST DEWPOINTS IN THE SINGLE
DIGITS AND TEENS. THIS DRY AIR IS BEING ACCOMPANIED BY GUSTY
WNW/NW WINDS. HIGH PRESSURE CENTERED OVER THE MID MISSISSIPPI
VALLEY WILL BUILD EAST OVER THE CAROLINAS BY LATE TONIGHT. WITH
LOW DEWPOINTS AND CLEAR SKIES...WINDS SHOULD DIMINISH LATE TONIGHT
PER LATEST RAP MODEL WHICH WILL ALLOW MINIMUM TEMPERATURES AREA-
WIDE IN THE UPPER TEENS TO LOWER 20S EXCEPT FOR SOME MIDDLE 20S
ALONG THE OUTER BANKS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
AS OF 320 PM FRIDAY...SATURDAY WILL BEGIN CLEAR AND COLD WITH HIGH
PRESSURE RIDGE AXIS ALMOST OVERHEAD. THE HIGH WILL SHIFT OFFSHORE
DURING THE AFTERNOON ALLOWING FOR A RETURN S/SSW FLOW WITH
INCREASING MOISTURE BELOW 700 MB BY LATE AFTERNOON AND AN INCREASE
IN CLOUDINESS. MAXIMUM TEMPERATURES USING A CONSENSUS BLEND OF
MODELS YIELDS VALUES IN THE LOWER TO MIDDLE 40S AREA-WIDE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM FRI...YESTERDAY THE ECMWF WAS CLEARLY BETTER THAN THE
GFS FOR THE EXTENDED. TODAY THOUGH THE GFS HAS COME INTO MUCH
BETTER AGREEMENT WITH THE ECMWF...SO AM USING A BLEND OF THE TWO
FOR THE EXTENDED PORTION. A BROAD UPPER TROF WILL REMAIN OVER THE
EASTERN HALF OF THE NATION THROUGH TUESDAY NIGHT...BUT THEN A
ZONAL PATTERN BEGINS TO DEVELOP ON WEDNESDAY. THREE SYSTEMS AFFECT
THE FORECAST AREA DURING THIS TIME. THE FIRST IS A FAST- MOVING
FRONT THAT PASSES THROUGH SATURDAY NIGHT. GUIDANCE POPS A BIT
WETTER THAN YESTERDAY WITH MEASURABLE PRECIP FORECAST FOR ALL
AREAS. USING CRITICAL THICKNESSES YIELDS A RAIN/SNOW MIX. DUE TO
THE SPEED OF THE SYSTEM AMOUNTS WILL BE LIGHT AND NO ACCUMULATION
IS EXPECTED. THE 2ND FRONT TUESDAY/TUESDAY NIGHT WILL HAVE LITTLE
MOISTURE TO WORK WITH SO NO PRECIP IS FORECAST WITH THIS ONE. IT
WILL ONLY BRING A WIND SHIFT AND A SLIGHTLY COOLER AIRMASS. THE
BEST CHANCE FOR RAIN WILL COME ON FRIDAY WITH THE APPROACH OF THE
NEXT FRONT. FORECAST SOUNDINGS SHOW RATHER GOOD SUPPLY OF MOISTURE
THIS TIME SO HAVE INCLUDED CHANCE POPS.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 1250 PM FRIDAY...VFR CONDITIONS ARE EXPECTED THROUGH THE
TAF CYCLE. GUSTY WNW/NW WINDS WILL PERSIST THROUGH LATE AFTERNOON
WITH A FEW GUSTS IN EXCESS OF 30 MPH. AS AXIS OF HIGH PRESSURE
RIDGE SETTLES OVER THE REGION TONIGHT...EXPECT WINDS TO QUICKLY
DIMINISH.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM FRI...VFR THROUGH THE PERIOD. FAST-MOVING FRONT PASSING
THROUGH SATURDAY NIGHT WILL BRING A CHANCE OF A LIGHT RAIN/SNOW
MIX THROUGH LATE SATURDAY EVENING. GUSTY WEST WIND FORECAST ON
SUNDAY AROUND 15-20 KNOTS.
&&
.MARINE...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 325 PM FRIDAY...THE PRIMARY CAA SURGE BEHIND THE COLD FRONT
HAS SUBSIDED AS WINDS PEAKED AROUND 15Z OR 16Z. STILL SEEING GUSTS
WELL INTO THE 20S AND WILL KEEP SMALL CRAFT ADVISORY AS IS WITH
THE SOUTHERN WATERS ENDING AT 00Z...THE SOUNDS AT 03Z AND
ELSEWHERE BY 06Z TONIGHT. SEAS ARE GENERALLY 4 TO 6 FEET AT THE
MOMENT AND SHOULD LIKEWISE SUBSIDE PER WAVEWATCH AND LOCAL NWPS
MODEL. WITH AXIS OF RIDGE BUILDING OVER THE WATERS...WINDS AND
SEAS SHOULD DIMINISH WITH WINDS OF 10 KNOTS OR LESS AND SEAS 4
FEET OR LESS EXPECTED BY SATURDAY MORNING.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 230 PM FRI...USED A CONSENSUS BLEND OF THE LATEST RUNS OF THE
GFS AND ECMWF FOR THE EXTENDED MARINE FORECAST. FAST-MOVING COLD
FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT. A BRIEF PERIOD OF
MARGINAL SMALL CRAFT WINDS/SEAS APPEARS LIKELY SUNDAY AFTERNOON
INTO SUNDAY NIGHT. HIGH PRESSURE ALONG WITH A LOOSE PRESSURE
GRADIENT WILL BUILD IN BEHIND THE SYSTEM FOR MONDAY. THE HIGH WILL
NOT LINGER HOWEVER AND IT MOVES OFF TUESDAY. THE NEXT COLD FRONT
WILL MOVE THROUGH TUESDAY AND TUESDAY NIGHT WITH WINDS SHIFTING TO
THE NORTH FOR WEDNESDAY. SMALL CRAFT SEAS ARE FORECAST FOR THE
COASTAL WATERS NORTH OF OREGON INLET BEHIND THE SYSTEM ON
WEDNESDAY.
&&
.FIRE WEATHER...
WHILE RELATIVE HUMIDITY VALUES WILL REMAIN VERY LOW ON
SATURDAY...WINDS WILL SUBSIDE WHICH SHOULD LESSEN THE OVERALL FIRE
DANGER.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ130-
135.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SATURDAY FOR AMZ150-152-
154.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ156-
158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/HSA
FIRE WEATHER...CTC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 PM CST FRI FEB 1 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
345 PM CDT FRI FEB 1 2013
AT 3 PM...THE WATER VAPOR IMAGERY SHOWED A SHORT WAVE TROUGH MOVING
SOUTHEAST THROUGH LAKE WINNIPEG. AT THE THE SURFACE...A COLD
FRONT...LOCATED JUST SOUTH OF LAKE WINNE PEG...WAS PRODUCING SNOW
ACROSS THE EASTERN DAKOTAS...AND NORTHWEST AND WEST CENTRAL
MINNESOTA. THIS SNOW WAS REDUCING VISIBILITIES TO 3/4 MILES AT FARGO
NORTH DAKOTA.
FOR TONIGHT...THE 01.12Z MESO AND DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT THAT SHORT WAVE TROUGH AND COLD FRONT TO OUR NORTHWEST
WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA THIS EVENING AND EARLY
OVERNIGHT. MODERATE 270 TO 280K ISENTROPIC LIFT /2 TO 4
MICROBARS/SEC/ DEVELOPS AHEAD OF THIS SYSTEM. THIS IS BRINGING THE
WARMER AND MORE MOIST /DEW POINTS IN THE LOWER AND MID 20S/ AIR
ALOFT. THIS WARMS THE ATMOSPHERIC COLUMN INTO THE DENDRITIC GROWTH
ZONE AND THE MOISTURE SATURATES IT. 01.09Z SREF SHOWS THAT 50 TO
70 PERCENT OF THE ENSEMBLE FAMILY HAS OVER 200 MB OF DENDRITIC
GROWTH THIS EVENING. THE ROCHESTER RAP BUFKIT SOUNDING SHOWS AT
LEAST 10K FEET IN THE DENDRITIC GROWTH ZONE BETWEEN 02.00Z AND
02.06Z. MEANWHILE THE GFS AND NAM BUFKIT SOUNDINGS HAVE A MUCH
SHORTER TIME. THIS WILL AFFECT THE SNOW RATIOS. THE RAP WOULD
SUGGEST 25-30 TO 1 SNOW TO LIQUID RATIOS. MEANWHILE THE GFS AND NAM
WOULD SUGGEST 17-23 TO 1 SNOW TO LIQUID RATIOS. SINCE THE SYSTEM IS
MOVING SO FAST...TRENDED MORE TOWARD THE GFS AND NAM SOLUTIONS.
THIS WOULD PRODUCE A 1 TO 2 INCH SNOW BAND ACROSS NORTHEAST IOWA AND
AND SOUTHWEST WISCONSIN...AND AROUND AN INCH NORTHWARD TO WISCONSIN
10.
ON SATURDAY AFTERNOON AND NIGHT...ANOTHER SHORT WAVE TROUGH WILL
MOVE SOUTHEAST THROUGH THE REGION. UNLIKE YESTERDAY...HAS THE LEFT
ENTRANCE REGION OF THE 250 MB JET A BIT FURTHER SOUTHEAST. AS A
RESULT...THE OMEGA IS NOT AS STRONG OR DEEP AS IT WAS YESTERDAY.
DESPITE THIS THERE IS MODERATE 270 TO 280K LIFT AHEAD OF THIS WAVE
AND THIS WILL ONCE AGAIN BRING SOME MOISTURE AND WARMER AIR ALOFT
FROM THE NORTHERN AND CENTRAL PLAINS. HOWEVER 01.09Z SREF SHOWS
FEWER MEMBERS HAVING 200 MB OR GREATER OF DENDRITIC GROWTH. THE COBB
DATA SUGGESTS 17-22 TO 1 SNOW TO LIQUID RATIOS. THIS WOULD RESULT IN
AROUND AN INCH OF SNOW FOR MUCH OF THE AREA.
FROM LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT...THE MODELS SHOW YET
ANOTHER SHORT WAVE TROUGH WILL BE MOVING SOUTHEAST THROUGH THE
REGION. BY THIS TIME...THE AIR MASS WILL BE A BIT WARMER. AS A
RESULT...THE BEST ISENTROPIC LIFT IS TAKING PLACE BETWEEN 280 AND
300K. WITH THE AIR MASS WARMER...THERE IS LESS OF A LAYER IN
DENDRITIC GROWTH ZONE. HOWEVER THERE IS A BIT MORE MOISTURE FOR THIS
SYSTEM TO WORK WITH...SO IT LOOKS LIKE SNOW TOTALS WILL RANGE FROM 1
TO 2 INCHES.
OVERALL...IT LOOKS LIKE SNOW TOTALS DURING THE NEXT 3 DAYS WILL
RANGE FROM 2 TO 5 INCHES.
.LONG TERM...MONDAY THROUGH FRIDAY
345 PM CDT FRI FEB 1 2013
ON MONDAY NIGHT AND TUESDAY MORNING...ANOTHER SHORT WAVE WILL BE
MOVING SOUTHEAST THROUGH THE REGION. LIKE THE SYSTEM ON SUNDAY AND
SUNDAY NIGHT...THERE IS NOT MUCH OF THE THE ATMOSPHERIC COLUMN IN
THE DENDRITIC GROWTH ZONE...BUT THERE IS MORE MOISTURE FOR THIS
SYSTEM TO WORK WITH. AS A RESULT...THE SNOW TO LIQUID RATIOS LOOK TO
BE 15-20 TO 1. WITH A TENTH TO 2 TENTHS OF INCH OF QPF...THERE COULD
BE THE POTENTIAL OF ANOTHER 1 TO 3 INCHES OF SNOW.
IT STILL LOOKS LIKE ANOTHER SYSTEM WILL AFFECT THE AREA FROM
WEDNESDAY NIGHT INTO THURSDAY. HOWEVER THE MODELS HAVE BEEN MUCH
LESS CONSISTENT WITH THEIR PRECIPITATION AMOUNTS AND THE LOCATION OF
THIS SYSTEMS WARM FRONT. AS A RESULT...THERE IS MUCH LESS CERTAINTY
THAN THE PREVIOUS 4 SYSTEMS.
&&
.AVIATION...
1200 AM CST FRI FEB 1 2013
CLOUDS WILL BE ON THE INCREASE LATE THIS AFTERNOON...QUICKLY
LOWERING/THICKENING BY 00Z AS AN UPPER LEVEL SHORTWAVE APPROACHES.
ENOUGH THERMODYNAMIC/UPPER LEVEL FORCING FOR -SN PRODUCTION. ONSET
SHOULD BE AROUND THE 00Z TIME FRAME...AND VSBYS SHOULD QUICKLY DROP
TO AROUND 1-2SM AFTER IT STARTS. WILL KEEP TAFS AT 2SM FOR NOW. DEEP
DENDRITIC SNOW GROWTH REGION...AND EXPECT LARGER FLAKES...DRY SNOW
THAT COULD ADD UP QUICKLY. THE SYSTEM MOVES THROUGH AT A GOOD CLIP
THOUGH...SO 1-2 INCHES IS EXPECTED. MOST ACCUMULATIONS SHOULD BE
OVER BY 06Z.
THE REGION WILL BE UNDER AN ACTIVE NORTHWEST FLOW...WHICH WILL PUSH
SHORTWAVE AFTER SHORTWAVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
THE TAF SITES WILL BE IMPACTED BY SIMILAR SYSTEMS SAT AND SUN
NIGHTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
344 PM CST FRI FEB 1 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1128 AM MST FRI FEB 1 2013
.UPDATE...THE UPPER LEVEL DISTURBANCE IS MOVING SOUTHEAST ACROSS
WYOMING THIS MORNING...AND SCATTERED SNOW SHOWERS ARE DEVELOPING
IN NORTHERN WYOMING WITH THE WAVE. THESE SHOWERS WILL MOVE
SOUTHEAST INTO THE FORECAST AREA THROUGH THIS AFTERNOON. INCREASED
POPS TO A MORE SCATTERED COVERAGE ACROSS THE EASTERN PLAINS BASED
ON CURRENT TRENDS AND AS MOST 12Z MODELS DEPICT THIS SITUATION.
FOLLOWED THE RUC TREND FOR TIMING...WITH SHOWERS MOVING INTO THE
NORTHERN ZONES OVER THE NEXT HOUR OR TWO...THEN MOVING INTO THE
SOUTHERN ZONES LATER THIS AFTERNOON. DID NOT MAKE ANY SIGNIFICANT
CHANGES TO SNOW CHANCES ACROSS THE HIGH COUNTRY. SOME PARTIAL
CLEARING AHEAD OF THE WAVE HAS ALLOWED TEMPERATURES TO INCREASE
MORE THAN ORIGINALLY FORECAST...SO BUMPED UP TEMPS
ACCORDINGLY...ESPECIALLY ACROSS THE EASTERN PLAINS. COULD SEE A
FEW OF THE SHOWERS START AS LIGHT RAIN AS A RESULT OF THE WARMER
TEMPS...BUT EXPECT THESE TO QUICKLY CHANGE OVER TO SNOW. RJM
.AVIATION..18Z TAF ISSUANCE...
CLOUD BASES WILL LOWER OVER THE CWA INTO MID AFTERNOON AS SNOW
SHOWERS BECOME FAIRLY WIDESPREAD OVER THE CWA. CEILINGS AND
VISIBILITIES IN SNOW WILL FREQUENTLY BE MVFR BETWEEN 20Z AND
01Z SATURDAY. THERE WILL ALSO BE PERIODS OF IFR VISIBILITIES
ASSOCIATED WITH THE HEAVIER SNOW SHOWERS. THE SNOW SHOWERS WILL
BE ACCOMPANIED BY A PERIOD OF CLEAR OR RIME ICING UP THROUGH 15000
FEET MSL. THE MOUNTAINS WILL BE OBSCURED THROUGH THIS EVENING.
AFTER THAT TIME...VFR CONDITIONS WILL RETURN TO THE CWA AND PERSIST
THROUGH EARLY NEXT WEEK.
WEST TO NORTHWEST SURFACE WINDS WILL GUST AS HIGH AS 45 KNOTS
THROUGH 01Z SATURDAY...MAINLY OVER SOUTHEAST WYOMING. WIND
GUSTS WILL REMAIN AS HIGH AS 35 KNOTS TONIGHT AND SATURDAY IN
AREAS ALONG AND WEST OF THE LARAMIE RANGE. A WEAK TO MODERATE
MOUNTAIN WAVE WILL EXIST INTO THE EARLY EVENING TO THE LEE OF
THE SNOWY RANGE AS WELL AS LARAMIE PEAK.
WEILAND
&&
.PREV DISCUSSION... /ISSUED 419 AM MST FRI FEB 1 2013/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...
SHORTWAVE OVER FAR WESTERN MONTANA WILL QUICKLY MAKE ITS WAY
ACROSS SOUTHEAST WYOMING BY THIS AFTERNOON. SNOW WILL MAINLY BE
FOUND AT HIGHER ELEVATIONS AHEAD OF THIS FAST MOVING DISTURBANCE.
UPPER LEVEL JET AND SHORTWAVE WILL LEND PLENTY OF UPPER LEVEL
DYNAMICS TODAY. MAIN LIMITING FACTOR WILL BE RELATIVELY DRY
NORTHWEST FLOW ALOFT AND DOWN SLOPE EAST OF THE LARAMIE RANGE.
ALONG AND WEST OF THE LARAMIE RANGE THERE WILL BE ENOUGH MOISTURE
UNDER UP SLOPE FLOW FOR MORE WIDESPREAD SNOW...ESPECIALLY IN THE
MOUNTAINS. WINTER WEATHER ADVISORY IS IN EFFECT THROUGH 9 PM THIS
EVENING FOR THE SNOWY AND SIERRA RANGES WHERE 6 TO 9 INCHES OF
SNOW IS GENERALLY EXPECTED. GIVEN A 1 TO 4 INCHES HAVE ALREADY
FALLEN SINCE LAST EVENING...SHOULD EASILY HIT ADVISORY CRITERIA.
MAY EVEN SEE A FEW LOCATIONS APPROACH ONE FOOT OF SNOW BEFORE
TAPERING OFF THIS EVENING. ALSO IT WILL BE WINDY WITH
SIGNIFICANTLY REDUCED VISIBILITIES IN THE MOUNTAINS DUE TO BLOWING
SNOW.
INTO THE PLAINS ISOLATED TO SCATTERED SNOW SHOWERS CAN BE EXPECTED
THIS AFTERNOON. THE COMBINATION OF UPPER LEVEL LIFT AND LOW LEVEL
INSTABILITY SHOULD BE ENOUGH TO FIRE SOME SNOW SHOWERS OFF THE
NORTHERN LARAMIE RANGE BY EARLY THIS AFTERNOON. SHOWER ACTIVITY
WILL PROPAGATE SOUTHEAST UNDER NORTHWEST FLOW ALOFT. LIFTED INDEX
1 TO -1 THIS AFTER OVER SOUTHEAST WYOMING AND EXTENDING INTO THE
WESTERN NEBRASKA PANHANDLE. COULD SEE A FEW SNOW SHOWERS ON THE
HEAVIER SIDE PRODUCING QUICK SHOTS OF ACCUMULATING SNOW. ALTHOUGH
MOST OF THE AREA WILL SEE LITTLE TO NO ACCUMULATION...ISOLATED
SPOTS COULD EASILY PICK UP AN INCH OF SNOW. SNOW SHOWERS WILL
QUICKLY DIE OFF THIS EVENING WITH THE LOST OF SURFACE HEATING AND
UPPER LEVEL DYNAMICS WITH THE SHORTWAVE MOVING INTO NEBRASKA AND
KANSAS.
OTHER CONCERN TODAY IS THE WINDS. CANCELLED THE HIGH WIND WARNING
WHICH WAS IN EFFECT THROUGH 11 AM THIS MORNING. WINDS NEVER
MATERIALIZED TO THE EXTENT THAT WAS PREVIOUSLY EXPECTED. CURRENTLY
WINDS 25 TO 35 MPH WITH A FEW RANDOM GUSTS AROUND 50 MPH IN THE
ARLINGTON AREA. STRONGEST WINDS SEEM TO BE STAYING ABOVE THE
INVERSION...AT LEAST THAT IS WHAT MODEL WIND AND STABILITY CROSS
SECTIONS SUGGEST. SHOULD BE ABLE TO MIX DOWN SOME OF THOSE WINDS
LATER TODAY...BUT BASED ON MODEL FORECASTS WINDS SHOULD STAY BELOW
WIND WARNING CRITERIA TODAY. STILL A FEW GUSTS TO 60 MPH AREA NOT
COMPLETELY OUT OF THE QUESTION WITH THE PASSAGE OF THE SHORTWAVE.
ONCE THE SHORTWAVE PASSES...SNOW WILL END AND SKIES WILL BEGIN TO
CLEAR. THIS SHOULD BE THE BEGINNING OF AN EXTENDED DRY PERIOD
ACROSS THE FORECAST AREA. NO MENTION FOR PRECIPITATION THROUGH
SUNDAY NIGHT AS DRY NORTHWEST FLOW AND BUILDING UPPER LEVEL RIDGE
KEEP POP CHANCES VERY VERY LOW.
LONG TERM...MONDAY THROUGH THURSDAY...
MILD AND MAINLY DRY WEATHER EXPECTED OVER THE CWA DURING THIS
PERIOD WITH NO SIGNIFICANT SYSTEMS SEEN AFFECTING THE AREA. MODELS
DEPICT ONE SHORTWAVE PASSING BY LATE ON WEDNESDAY BRINGING SOME
MINOR COOLING BEHIND IT FOR THURSDAY. GFS DRY WITH THIS SYSTEM WHILE
ECMWF PAINTS SOME LOW QPF IN ASSOCIATION WITH IT. LATEST ECMWF
RUN HAS DECREASED QPF AND WILL SEE IF IT EVENTUALLY COMES IN LINE
WITH THE GFS SOLUTION. FOR NOW WILL KEEP SOME VERY LOW "SILENT"
POPS FOR THIS SYSTEM. OTHERWISE NW FLOW EARLY NEXT WEEK WILL BACK
TO WESTERLY AS UPPER RIDGE AXIS PASSES ACROSS LATE TUESDAY. UPPER
RIDGE THEN REBUILDS OVER THE REGION THURSDAY IN WAKE OF PREVIOUSLY
MENTIONED SHORTWAVE.
FIRE WEATHER...
UPPER LEVEL DISTURBANCE TO BRING SNOW TO THE MOUNTAINS OF SOUTHEAST
WYOMING TODAY. ISOLATED TO SCATTERED SNOW SHOWERS OVER THE REST
OF SOUTHEAST WYOMING...AND INTO THE NEBRASKA PANHANDLE THIS
AFTERNOON. CLEARING SKIES TONIGHT BEHIND THE DISTURBANCE THEN
WARMER AND DRY THROUGH NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY UNTIL 9 PM FRIDAY FOR WYZ112-WYZ114.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM...RE