Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/21/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
912 AM MST SAT JAN 19 2013
.UPDATE...
&&
.SHORT TERM...IN THE WAKE OF LAST NIGHTS WEAK TROF THERE IS STILL
SOME GUSTY WINDS IN THE MOUNTAINS AND FOOTHILLS. THESE WINDS WILL
CONTINUE TO DECREASE THIS AFTERNOON. BASED ON THE MORNING DENVER
SOUNDING...TEMPERATURES MIGHT BE A DEGREE OR TWO COOLER FROM
YESTERDAY WITH SLIGHT COOLING IN THE 600-700MB LAYER. WINDS
EXPECTED TO INCREASE AGAIN LATER TONIGHT ALONG EAST SLOPES AS NEXT
WEAK RIPPLE MOVES THROUGH THE FLOW.
.AVIATION...CURRENT TAFS LOOK GOOD AND STILL PLANNING TO PLAY THE
LONGMONT ANTICYCLONE THIS AFTERNOON WITH A LIGHT EAST TO SOUTHEAST
WIND AT DEN AND APA. BJC MAY STILL SEE A MORE WESTERLY COMPONENT
THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 243 AM MST SAT JAN 19 2013/
SHORT TERM...DRY NW FLOW ALOFT WILL CONTINUE TODAY AND TONIGHT. A
MTN WAVE EARLY THIS MORNING IS ALLOWING FOR SOME GUSTY NWLY WINDS
IN AND NR THE FOOTHILLS WHICH WILL LINGER THRU THE MID MORNING
HOURS BEFORE DECREASING SOME BY MIDDAY. OTHERWISE GUSTY NW WINDS
WILL ALSO OCCUR ALONG AND NR THE WY-NE BORDER ESPECIALLY LATER
THIS MORNING INTO THE AFTN HOURS AS BETTER MIXING DEVELOPS. AS FOR
HIGHS READINGS WILL BE IN THE 50S ACROSS NERN CO. ONCE AGAIN IN
THE HIGHER MTN VALLEYS INVERSIONS WILL LEAD TO WIDE TEMP SPREADS
ESPECIALLY ACROSS ZONE 32.
FOR TONIGHT ANOTHER MTN WAVE MAY DEVELOP AFTER MIDNIGHT LEADING TO
AN INCREASE IN WINDS OVER THE HIGHER MTNS AND FOOTHILLS. AT THIS
TIME IT APPEARS SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED TO CONTINUE OVER
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. ON MONDAY...THE FLOW
IS PROGGED TO BECOME NORTH-NORTHWESTERLY AND INCREASE A BIT IN
SPEED. BY TUESDAY MORNING AT 12Z IT WEAKENS AND IS BACK TO A
NORTHWESTERLY DIRECTION. AT THAT TIME AN UPPER RIDGE AXIS IS
LOCATED OVER THE GREAT BASIN. THE SYNOPTIC SCALE ENERGY IS PROGGED
TO BE BENIGN SUNDAY THROUGH MONDAY NIGHT. THE BOUNDARY LAYER FLOW
LOOKS TO BE UPSLOPING FOR THE PLAINS AND FOOTHILLS SUNDAY...WITH
NORMAL DUIRNAL PATTERNS FOR SUNDAY NIGHT INTO MONDAY. LOW LEVEL
TROUHGING EAST OF THE MOUNTAINS SETS UP LATER SUNDAY THROUGH
TUESDAY NIGHT...BUT THE GRADIENT IS PRETTY WEAK. A MIX OF NORMAL
TRENDS TO DOWNSLOPING SHOULD PREVAIL THOSE TWO PERIODS. MOISTURE
CONTINUES TO BE QUITE LIMITED ACCORDING TO THE MODELS. THERE IS A
LITTLE OVER THE PLAINS WITH THE UPSLOPE SUNDAY AFTERNOON AND
EVENING...MORE SO ON THE GFS. THE GFS ALSO SHOWS A TAD IN THE
UPPER LEVELS MONDAY AND MONDAY NIGHT...BUT THAT`S ABOUT IT. THERE
IS NO MEASURABLE PRECIPITATION NOTED ON THE QPF FIELDS FOR THE
FORECAST AREA SUNDAY THROUGH MONDAY NIGHT. NO POPS. FOR
TEMPERATURES...SUNDAY`S HIGHS ARE 4-8 C COLDER THAN TODAY`S
EXPECTED HIGHS. MONDAY`S READINGS WARM UP 3-5 C OVER SUNDAY`S. FOR
THE LATER DAYS...TUESDAY THROUGH FRIDAY...MODELS HAVE PRETTY WEAK
NORTHWESTERLY FLOW ALOFT FOR THE CWA TUESDAY AND WEDNESDAY.
BY THURSDAY...THE ECMWF AND GFS START DEVELOPING AN UPPER TROUGH
NORTH AND NORTHEAST OF COLORADO. THE FLOW ALOFT INCREASES AND IS
ZONAL ON THURSDAY. BY FRIDAY...A MEAN TROUGH IS PROGGED TO COVER
THE EASTERN HALF OF NORTH AMERICA...AND AN UPPER RIDGE IS OVER
THE GREAT BASIN. THE GFS BRINGS SOME MOISTURE OVER THE CWA
THURSDAY AND THURSDAY NIGHT. THE ECMWF DOES NOT. THE OTHER DAYS
ARE PRETTY DRY ON BOTH MODELS. WILL KEEP POPS OUT FOR NOW.
TEMPERATURES REMAIN ABOVE SEASONAL NORMALS THROUGH THE PERIOD.
AVIATION...WEST WINDS HAVE SPREAD ACROSS THE AIRPORT EARLY THIS
MORNING BUT SHOULD BECOME MORE SWLY AFTER SUNRISE. BY 16Z WINDS
MAY BECOME MORE SLY. FOR THIS AFTN THERE IS QUITE A DIFFERENCE IN
WIND FCSTS AS THE HRRR AND RAP INDICATE A LONGMONT ANTI-CYCLONE
DEVELOPING WITH WINDS BECOMING MORE ELY BY EARLY AFTN WHILE THE
NAM HAS A WLY COMPONENT. WITH NWLY FLOW OVER THE CHEYENNE RIDGE
THAT WOULD FAVOR A POTENTIAL ANTI-CYCLONE SO WILL TREND TAF
TOWARDS THE HRRR/RAP SOLUTION. BY EARLY EVENING WINDS SHOULD
GRADUALLY TRENDS TOWARDS DRAINAGE. VFR CONDITIONS WILL BE IN PLACE
TODAY THRU TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
243 AM MST SAT JAN 19 2013
.SHORT TERM...DRY NW FLOW ALOFT WILL CONTINUE TODAY AND TONIGHT. A
MTN WAVE EARLY THIS MORNING IS ALLOWING FOR SOME GUSTY NWLY WINDS
IN AND NR THE FOOTHILLS WHICH WILL LINGER THRU THE MID MORNING
HOURS BEFORE DECREASING SOME BY MIDDAY. OTHERWISE GUSTY NW WINDS
WILL ALSO OCCUR ALONG AND NR THE WY-NE BORDER ESPECIALLY LATER
THIS MORNING INTO THE AFTN HOURS AS BETTER MIXING DEVELOPS. AS FOR
HIGHS READINGS WILL BE IN THE 50S ACROSS NERN CO. ONCE AGAIN IN
THE HIGHER MTN VALLEYS INVERSIONS WILL LEAD TO WIDE TEMP SPREADS
ESPECIALLY ACROSS ZONE 32.
FOR TONIGHT ANOTHER MTN WAVE MAY DEVELOP AFTER MIDNIGHT LEADING TO
AN INCREASE IN WINDS OVER THE HIGHER MTNS AND FOOTHILLS. AT THIS
TIME IT APPEARS SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA.
.LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED TO CONTINUE OVER
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. ON MONDAY...THE FLOW
IS PROGGED TO BECOME NORTH-NORTHWESTERLY AND INCREASE A BIT IN
SPEED. BY TUESDAY MORNING AT 12Z IT WEAKENS AND IS BACK TO A
NORTHWESTERLY DIRECTION. AT THAT TIME AN UPPER RIDGE AXIS IS
LOCATED OVER THE GREAT BASIN. THE SYNOPTIC SCALE ENERGY IS PROGGED
TO BE BENIGN SUNDAY THROUGH MONDAY NIGHT. THE BOUNDARY LAYER FLOW
LOOKS TO BE UPSLOPING FOR THE PLAINS AND FOOTHILLS SUNDAY...WITH
NORMAL DUIRNAL PATTERNS FOR SUNDAY NIGHT INTO MONDAY. LOW LEVEL
TROUHGING EAST OF THE MOUNTAINS SETS UP LATER SUNDAY THROUGH
TUESDAY NIGHT...BUT THE GRADIENT IS PRETTY WEAK. A MIX OF NORMAL
TRENDS TO DOWNSLOPING SHOULD PREVAIL THOSE TWO PERIODS. MOISTURE
CONTINUES TO BE QUITE LIMITED ACCORDING TO THE MODELS. THERE IS A
LITTLE OVER THE PLAINS WITH THE UPSLOPE SUNDAY AFTERNOON AND
EVENING...MORE SO ON THE GFS. THE GFS ALSO SHOWS A TAD IN THE
UPPER LEVELS MONDAY AND MONDAY NIGHT...BUT THAT`S ABOUT IT. THERE
IS NO MEASURABLE PRECIPITATION NOTED ON THE QPF FIELDS FOR THE
FORECAST AREA SUNDAY THROUGH MONDAY NIGHT. NO POPS. FOR
TEMPERATURES...SUNDAY`S HIGHS ARE 4-8 C COLDER THAN TODAY`S
EXPECTED HIGHS. MONDAY`S READINGS WARM UP 3-5 C OVER SUNDAY`S. FOR
THE LATER DAYS...TUESDAY THROUGH FRIDAY...MODELS HAVE PRETTY WEAK
NORTHWESTERLY FLOW ALOFT FOR THE CWA TUESDAY AND WEDNESDAY.
BY THURSDAY...THE ECMWF AND GFS START DEVELOPING AN UPPER TROUGH
NORTH AND NORTHEAST OF COLORADO. THE FLOW ALOFT INCREASES AND IS
ZONAL ON THURSDAY. BY FRIDAY...A MEAN TROUGH IS PROGGED TO COVER
THE EASTERN HALF OF NORTH AMERICA...AND AN UPPER RIDGE IS OVER
THE GREAT BASIN. THE GFS BRINGS SOME MOISTURE OVER THE CWA
THURSDAY AND THURSDAY NIGHT. THE ECMWF DOES NOT. THE OTHER DAYS
ARE PRETTY DRY ON BOTH MODELS. WILL KEEP POPS OUT FOR NOW.
TEMPERATURES REMAIN ABOVE SEASONAL NORMALS THROUGH THE PERIOD.
&&
.AVIATION...WEST WINDS HAVE SPREAD ACROSS THE AIRPORT EARLY THIS
MORNING BUT SHOULD BECOME MORE SWLY AFTER SUNRISE. BY 16Z WINDS
MAY BECOME MORE SLY. FOR THIS AFTN THERE IS QUITE A DIFFERENCE IN
WIND FCSTS AS THE HRRR AND RAP INDICATE A LONGMONT ANTI-CYCLONE
DEVELOPING WITH WINDS BECOMING MORE ELY BY EARLY AFTN WHILE THE
NAM HAS A WLY COMPONENT. WITH NWLY FLOW OVER THE CHEYENNE RIDGE
THAT WOULD FAVOR A POTENTIAL ANTI-CYCLONE SO WILL TREND TAF
TOWARDS THE HRRR/RAP SOLUTION. BY EARLY EVENING WINDS SHOULD
GRADUALLY TRENDS TOWARDS DRAINAGE. VFR CONDITIONS WILL BE IN PLACE
TODAY THRU TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MIAMI FL
101 PM EST SAT JAN 19 2013
.AVIATION...
LOW LEVEL TROUGH LOCATED NEAR KPBI WILL CONTINUE TO MOVE NORTHWARD
UP THE COAST THROUGH THE DAY. RAIN HAS ENDED SOUTH OF KFXE...AND
VFR CONDITIONS ARE EXPECTED SOUTH OF KFXE THROUGH TONIGHT. OLD
FRONTAL BOUNDARY REMAINS JUST SOUTH OF THE REGION AND MOSTLY
CLOUDY TO CLOUDY SKIES WILL PREVAIL THROUGH THE END OF THE PERIOD.
SOME LOW CIGS/VIS MAY BE POSSIBLE FOR KAPF...KFXE...AND KTMB
TONIGHT AS WINDS BECOME CALM AND A LAND BREEZE SETS UP.
OTHERWISE...LIGHT NORTHEAST WINDS ARE EXPECTED THIS
AFTERNOON...AND AGAIN AFTER 15Z SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 1104 AM EST SAT JAN 19 2013/
UPDATE...LOWERED POPS FOR BASED ON RADAR TRENDS. LOOKS LIKE WE
WILL HAVE PREDOMINATELY SCATTERED SHOWER ACTIVITY FROM NE BROWARD
AND ALONG THE PALM BEACH COAST WITH A SLIGHT CHANCE OF SHOWERS
ELSEWHERE THROUGH THE DAY. SOME SUNSHINE NOW SOUTH WITH BREAKS
DEVELOPING AT OTHER LOCALES SO IT LOOKS LIKE HIGHS ARE ON TRACK.
/GREGORIA
PREV DISCUSSION... /ISSUED 809 AM EST SAT JAN 19 2013/
UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT
RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A
GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME
TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH
COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE
OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE
DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY
DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST.
THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY,
BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD
MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO
MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO
WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS
ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T.
/GREGORIA
PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/
AVIATION...
MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS
MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN
TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT
AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS
WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT
VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY
CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK
ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z.
PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/
DISCUSSION...
AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE
THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED
FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS
ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT
AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY,
MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE
EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO
FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL
SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN
AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A
MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT
FEW DAYS.
FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH,
MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF
PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT
WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT
MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES
WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST
ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL
TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH
FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER
50S.
BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH
WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF
THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK.
FIRE WEATHER...
A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM
NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC
COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES
ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE
LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH
WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE
NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY
BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND
THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP
DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE
WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN
BELOW THRESHOLDS AT THIS TIME.
MARINE...
FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE
REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO
BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE.
FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS
CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF
STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN
FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY
MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO
PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN
EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 66 78 65 78 / 30 20 20 20
FORT LAUDERDALE 67 79 67 79 / 30 20 20 20
MIAMI 66 80 66 80 / 30 20 20 20
NAPLES 63 77 63 76 / 10 10 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1104 AM EST SAT JAN 19 2013
.UPDATE...LOWERED POPS FOR BASED ON RADAR TRENDS. LOOKS LIKE WE
WILL HAVE PREDOMINATELY SCATTERED SHOWER ACTIVITY FROM NE BROWARD
AND ALONG THE PALM BEACH COAST WITH A SLIGHT CHANCE OF SHOWERS
ELSEWHERE THROUGH THE DAY. SOME SUNSHINE NOW SOUTH WITH BREAKS
DEVELOPING AT OTHER LOCALES SO IT LOOKS LIKE HIGHS ARE ON TRACK.
/GREGORIA
&&
.PREV DISCUSSION... /ISSUED 809 AM EST SAT JAN 19 2013/
UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT
RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A
GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME
TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH
COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE
OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE
DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY
DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST.
THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY,
BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD
MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO
MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO
WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS
ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T.
/GREGORIA
PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/
AVIATION...
MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS
MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN
TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT
AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS
WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT
VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY
CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK
ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z.
PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/
DISCUSSION...
AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE
THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED
FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS
ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT
AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY,
MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE
EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO
FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL
SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN
AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A
MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT
FEW DAYS.
FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH,
MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF
PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT
WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT
MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES
WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST
ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL
TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH
FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER
50S.
BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH
WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF
THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK.
FIRE WEATHER...
A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM
NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC
COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES
ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE
LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH
WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE
NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY
BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND
THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP
DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE
WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN
BELOW THRESHOLDS AT THIS TIME.
MARINE...
FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE
REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO
BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE.
FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS
CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF
STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN
FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY
MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO
PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN
EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 66 78 65 / 40 30 20 20
FORT LAUDERDALE 78 67 79 67 / 20 30 20 20
MIAMI 79 66 80 66 / 20 30 20 20
NAPLES 75 63 77 63 / 20 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
809 AM EST SAT JAN 19 2013
.UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT
RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A
GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME
TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH
COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE
OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE
DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY
DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST.
THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY,
BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD
MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO
MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO
WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS
ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T.
/GREGORIA
&&
.PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/
AVIATION...
MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS
MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN
TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT
AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS
WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT
VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY
CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK
ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z.
PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/
DISCUSSION...
AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE
THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED
FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS
ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT
AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY,
MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE
EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO
FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL
SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN
AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A
MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT
FEW DAYS.
FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH,
MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF
PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT
WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT
MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES
WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST
ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL
TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH
FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER
50S.
BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH
WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF
THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK.
FIRE WEATHER...
A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM
NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC
COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES
ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE
LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH
WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE
NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY
BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND
THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP
DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE
WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN
BELOW THRESHOLDS AT THIS TIME.
MARINE...
FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE
REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO
BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE.
FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS
CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF
STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN
FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY
MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO
PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN
EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 66 78 65 / 50 30 20 20
FORT LAUDERDALE 78 67 79 67 / 80 30 20 20
MIAMI 79 66 80 66 / 50 30 20 20
NAPLES 75 63 77 63 / 20 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
352 AM EST SAT JAN 19 2013
.DISCUSSION...
CURRENTLY...STRONG HI PRES RIDGE EXTENDING FROM THE CAROLINAS TO
THE NW GOMEX. THE USAF CAPE PROFILER AND THE KTBW VAD WIND
PROFILE SHOWING 25-30KTS OF ERLY FLOW 5KFT...DIMINISHING TO
15-25KTS AT THE KJAX VAD WIND PROFILE. RAP ANALYSIS SHOWS HIGH
REGIONAL MOISTURE THRU THE H100-H85 LYR ASSOCD WITH A MARINE
STRATOCU DECK. KMFL/KTBW EVENING SOUNDINGS HAVE A SATURATED
H100-H80 LYR TRAPPED BLO A STOUT SUBSIDENCE INVERSION...THOUGH
PWAT VALUES TOP OUT ARND 0.80". KJAX SOUNDING IS A BIT DRIER WITH
PWAT ARND 0.40". RADAR SHOWS PERIODIC BANDS OF LIGHT RAIN MVG
ONSHORE S OF CAPE CANAVERAL.
TODAY-TONIGHT...THE HI PRES RIDGE WILL MAINTAIN A DEEP/STEADY
NERLY SFC/LOW LVL FLOW AS IT GRADUALLY WEAKENS. LOW LVL MOISTURE
IS HIGH ENOUGH TO MAINTAIN ISOLD/SCT SHRAS...THOUGH ITS SHALLOW
DEPTH WILL LIMIT QPF TO 0.10" OR LESS. DEPTH/STRENGTH OF THE NE
FLOW WILL PUSH THESE SHRAS WELL INTO THE INTERIOR THRU THE AFTN.
PRECIP WILL END OVER THE INTERIOR OVERNIGHT AS WINDS DIMINISH BUT
WILL CONTINUE ALONG THE COAST.
THE DEEP ONSHORE FLOW WILL TAP MOIST/MILD OCEAN AIR TO KEEP TEMPS
ABV AVG. MAXES IN THE M/U70S...MINS IN THE M/U50S ALONG AND N OF
THE I-4 CORRIDOR AND L/M60S ALONG THE SPACE/TREASURE COASTS.
SUN...A WEAK INVERTED TROUGH IS FORECAST TO DEVELOP EAST OF
FLORIDA WHICH WILL BACK THE LOW LEVEL FLOW SOME...TO THE N/NE. IT
WILL ALSO PRODUCE A BAND OF MOISTURE CONVERGENCE EXTENDING FROM
THE ATLC SW ACROSS THE COAST TOWARDS OKEECHOBEE...WHICH SHOULD
PRODUCE BRING SOME SHOWERS ACROSS THE COAST MAINLY SOUTH OF THE
CAPE. SO WILL MAINTAIN A SMALL 20 POP THERE AS WELL AS SOUTHERN
INTERIOR SECTIONS THOUGH SOME AREAS COULD SEE A FEW PERIODS OF
RAIN WITH LOCALLY HIGHER RAIN CHANCES AND AMOUNTS. FORECAST MODEL
SOUNDINGS SHOW CONSIDERABLE STRATOCUMULUS CLOUDS ALONG WITH SOME
CIRRUS SO MORE CLOUDS THAN SUN EXPECTED. NONETHELESS...
TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
MID 70S. LESS ONSHORE FLOW SUNDAY NIGHT SHOULD ALLOW COASTAL
COMMUNITIES SOUTH OF THE CAPE TO COOL A FEW MORE DEGREES WITH LOWS
NEAR 60.
MON-FRI...THE WEEK BEGINS WITH A HIGHLY AMPLIFIED UPPER PATTERN
ACROSS THE U.S...RIDGE IN THE WEST AND TROUGH IN THE EAST.
MEANWHILE...AT THE SURFACE A REINFORCING HI PRES RIDGE WILL DROP
OUT OF CANADA AND BUILD INTO THE SE U.S. MONDAY AND TUESDAY AND
BRING COOLER AND ESPECIALLY DRIER CONDITIONS INTO MIDWEEK. PRIOR
TO INFLUX OF MUCH DRIER AIR...THERE STILL LOOKS TO BE ENOUGH
MOISTURE TO PRODUCE A FEW SHOWERS MONDAY ALG THE TREASURE COAST TO
OKEECHOBEE SO HAVE MAINTAINED SMALL 20 POP THERE. RAIN CHANCES
LOOK QUITE SLIM TUE-THU AND HAVE KEPT THE FORECAST DRY.
AFTER A MILD MONDAY...BOTH HIGH AND LOW TEMPERATURES ARE FORECAST
TO FALL AT OR SLIGHTLY BELOW NORMAL TUE-WED WITH UPPER 30S
POSSIBLE ACROSS NORTH LAKE COUNTY WED MORNING. FREEZING
TEMPERATURES ARE STILL NOT EXPECTED AT THIS TIME. HIGH TEMPS ARE
FORECAST TO RANGE FROM THE MID 60S NORTH OF ORLANDO TO THE LOWER
70S OKEECHOBEE/ TREASURE COAST. SOME MODERATION OF TEMP/MOISTURE
WILL OCCUR BY THU AS HIGH PRESSURE PUSHES EAST INTO THE ATLC AND A
MORE DIRECT ONSHORE FLOW DEVELOPS.
&&
.AVIATION...
THRU 20/00Z...PREVAILING CIGS BTWN FL040-060. ISOLD MVFR SHRAS E OF
KTIX-KISM-KOBE THRU 19/14Z. AFT 19/14Z...ISOLD MVFR SHRAS ALL SITES
WITH SFC WND G18-22KTS.
&&
.MARINE...
TODAY-TONIGHT...RIDGE AXIS OVER THE DEEP SOUTH WILL MAINTAIN A
MODERATE TO FRESH NERLY BREEZE THRU MID AFTN. THE RIDGE WILL
GRADUALLY WEAKEN THRU DAYBREAK SUN...ALLOWING WIND TO DIMINISH BLO
THE 20KT SCA THRESHOLD BY LATE AFTN. HOWEVER...THE NE COMPONENT WILL
CONTINUE TO PUSH SWELL ENERGY INTO THE E FL COAST...KEEPING SEAS ABV
SCA CRITERIA THRU EARLY SUN MORNING. WIND SCA EXPIRATION TIME OF 21Z
LOOKS REASONABLE...WILL EXTEND THE SCA FOR SEAS THRU 09Z SUN.
SUN-WED...INVERTED TROUGH DEVELOPING EAST OF THE WATERS WILL BACK
WINDS TO A MORE N/NE DIRECTION SUNDAY WITH SPEEDS AROUND 10-15 KTS
AND SEAS 4-6 FT. SO WILL LIKELY NEED A CAUTION HEADLINE AT LEAST
FOR THE GULF STREAM SUNDAY. WATERS WILL BE IN A LIGHT NORTHERLY
PRES GRAD MONDAY BUT NORTH WINDS WILL INCREASE MONDAY NIGHT/EARLY
TUE AS HIGH PRESSURE BUILDS OVER THE AREA FROM THE NORTHWEST.
THERE WILL LIKELY BE A BRIEF PERIOD OF HAZARDOUS BOATING CONDITIONS
WITH ADVISORIES ISSUED TUE/TUE NIGHT. SWAN MODEL BUILDS SEAS TO 6
FT OFFSHORE WOULD NOT BE SURPRISED TO SEE 7 FT IN THE GULF STREAM.
THEN WINDS DECREASE PRETTY QUICKLY WED AS HIGH PRESSURE CENTER
SETTLES OVER THE AREA WITH SEAS SUBSIDING.
&&
.FIRE WEATHER...
NO LOW RH CONCERNS THROUGH MONDAY THOUGH MIN RH VALUES WILL BE A
LITTLE LOWER...40 TO 45 PERCENT ORLANDO NORTHWARD...MONDAY AFTN.
COOLER AND MUCH DRIER AIR IS FORECAST TO OVERSPREAD THE AREA TUE
AND PRODUCE MIN RH VALUES BELOW 35 PERCENT WITH N/NW WINDS AROUND
15 MPH. WED COULD BE NEARLY AS DRY ACROSS THE INTERIOR BUT WINDS
LOOK LIGHTER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 60 73 55 / 20 10 10 10
MCO 76 59 76 57 / 20 10 10 10
MLB 75 65 77 61 / 30 20 20 20
VRB 75 65 78 60 / 30 20 20 20
LEE 75 57 75 55 / 20 10 10 10
SFB 75 59 75 57 / 20 10 10 10
ORL 75 59 75 58 / 20 10 10 10
FPR 76 65 77 61 / 30 20 20 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE
OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER
INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY
LINE TO SEBASTIAN INLET OUT 20 NM-WATERS FROM FLAGLER BEACH
TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS
FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET
20 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS AFTERNOON
TO 4 AM EST SUNDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO
VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM
SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS
FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20
NM-WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE
20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER
INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....KELLY
AREA FORECAST DISCUSSION
NWS CARIBOU ME
954 PM EST SUN JAN 20 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT TO CROSS THE REGION THIS EVENING. LOW PRESSURE
PASSES SOUTH OF THE AREA TUESDAY WITH A COLD AIR MASS TO REMAIN
ACROSS THE AREA ALL WEEK.&&
.NEAR TERM /THROUGH MONDAY/...
COLD ARCTIC AIR POURING INTO THE AREA ATTM ON VRY STRONG AND GUSTY
NW WNDS... AT 945 PM...STILL GETTING GUSTS OVR 40 MPH ACROSS NRN
AND NERN AREAS BEHIND THE SECONDARY ARCTIC BNDRY. HAVE DECIDED TO
XTND THE WND ADV SEVERAL MORE HRS - THRU 06Z TO ALLOW TIME FOR
WNDS TO COME DOWN A BIT. HAVE ALSO DCRSD POPS TO JUST ISOLD AS VRY
DRY AIR ARCTIC AIR WILL MAKE IT TUF TO GENERATE ANY MSRBL PRECIP
FROM THIS POINT ON...
UPDATE 1700L: PRIMARY ARCTIC BNDRY EXITING THE FA ATTM W/ SECONDARY
BNDRY ENTERING FAR NWRN AREAS. THIS SECONDARY BNDRY IS EXPECTED TO
SWEEP SEWRD ACROSS THE FA DURING THE EVE HRS AND WILL BE
ACCOMPANIED BY SOME SNOW SHOWERS SPCLY NRN AREAS. THIS FRONT WILL
BE FOLLOWED BY STRONG GUSTY NW WNDS AND STRONG CAA ALLOWING TEMPS
TO FALL RAPIDLY LATER THIS EVE AND THRU THE OVERNGT HRS. HAVE
ADJUSTED POPS TO BETTER FIT CURRENT AND EXPECTED TRENDS W/ ALL WND
CHILL WRNGS/ADVS AND THE WND ADV CONTG...
INTENSE AREA OF LOW PRESSURE CURRENTLY MOVING TO THE NORTH OF THE
STATE. LINE OF SNOW SHOWERS CURRENTLY MOVING THROUGH. SECONDARY
COLD FRONT STILL TO THE WEST OF NEW ENGLAND AND SHOULD MOVE ACROSS
THE STATE IN THE EARLY EVENING. EXPECT GUSTY CONDITIONS TO DEVELOP
AS COLD AIR MOVES IN. WILL KEEP WIND ADVISORY IN PLACE. HAVE
ADJUSTED WIND GUSTS A LITTLE LOWER FOR LATE AFTERNOON. FOR POP AND
WEATHER GRIDS HAVE INITIALIZED POPS WITH RUC13 THEN MANUALLY
ADJUSTED INCREASE POPS A LITTLE FURTHER TO SOUTH. LATER TONIGHT
EXPECT RAPID TEMPERATURE DROP ACCOMPANIED BY STRONG WINDS AND
GUSTY CONDITIONS SO WILL ALSO KEEP WIND CHILL ADVISORY FOR NORTH
AND WIND CHILL WATCH IN FAR NORTHWEST.&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
THE MAIN STORY FOR THIS PORTION OF THE FORECAST WILL BE BITTERLY
COLD TEMPERATURES. COMBINED WITH WITH THE BREEZY CONDITIONS WHICH
WILL CONTINUE MONDAY THIS WILL CREATE VERY LOW WIND CHILLS,
ESPECIALLY NORTH, WHERE VALUES WILL BE IN THE MINUS 20S AND MINUS
30S. HIGHS MONDAY IN THE NORTH WILL RANGE FROM 5 BELOW TO 5 ABOVE
ZERO WITH SOUTHERN AREAS SEEING HIGHS IN THE TEENS.
WINDS WILL ABATE FOR MONDAY NIGHT WITH TEMPERATURES DIPPING TO NEAR
OR BELOW MINUS 20 NORTH. ACROSS THE SOUTH, CLOUDS WILL INCREASE AS
A LOW PRESSURE SYSTEM DEVELOPS OFF THE MID ATLANTIC COAST AND
MOVES NORTH AND EAST. THE NORTHERN EDGE OF THE PRECIPITATION SHIELD
LOOKS TO SET UP VERY CLOSE TO COASTAL AREAS OF THE CWA WITH THE
NEW GFS TAKING THE SYSTEM SLIGHTLY FARTHER NORTH. IF THIS SOLUTION
WERE TO VERIFY IT COULD RESULT IN A COUPLE INCHES OF SNOW RIGHT
ALONG THE COAST. HOWEVER THE CANADIAN AND THE ECMWF REMAIN A BIT
FARTHER SOUTH SO AT THIS POINT OPTED TO MAINTAIN CONTINUITY WITH
PREVIOUS FORECAST KEEPING JUST CHANCE POPS IN ALONG THE COAST FOR
LATE MONDAY NIGHT INTO TUESDAY. OTHERWISE TUESDAY WILL FEATURE
MAINLY CLOUDY SKIES WITH VERY COLD TEMPERATURES. HIGHS LOOK TO BE
A COUPLE DEGREES COLDER THAN MONDAY`S VALUES MEANING MANY AREAS IN
THE NORTH WILL STAY AT OR BELOW ZERO.
AS THE AFOREMENTIONED LOW MOVES OFF TO THE NORTHEAST HEADING INTO TUESDAY
NIGHT AND WEDNESDAY THIS WILL DRAG THE CORE OF THE COLDEST AIR
DOWN OVER THE CWA. IN ADDITION, WINDS WILL PICK UP AGAIN WEDNESDAY
DUE TO THE GRADIENT BETWEEN THE DEPARTING LOW TO THE EAST AND HIGH
PRESSURE TO THE WEST. THIS WILL ONCE AGAIN RESULT IN BITTER WIND
CHILLS LIKELY REACHING AT LEAST ADVISORY LEVELS IN THE NORTH.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
IT LOOKS LIKE WE WILL GET A REPRIEVE FROM THIS LATEST ARCTIC
BLAST COME LATE WEEK AND THEN A RETURN TO ANOTHER POTENTIAL SHOT
OF ARCTIC AIR BY THE WEEKEND.
AN UPPER LEVEL IS FORECAST TO SWING ACROSS THE REGION BY WEDNESDAY
EVENING W/ANOTHER SHOT OF VERY COLD ARCTIC AIR TO INVADE THE
REGION. CLOUDS AND SCATTERED SNOW SHOWERS/FLURRIES WILL END BY
LATE EVENING W/SKIES CLEARING LATE IN THE NIGHT. THIS WILL SET THE
STAGE FOR ANOTHER VERY COLD NIGHT W/WINDS GRADUALLY DROP OFF AS
SFC HIGH PRES MOVES E FROM CANADA. WE COULD BE SEEING WIND CHILLS
HEADLINES AGAIN IN THURSDAY MORNING. A CAVEAT TO THIS IS THE ECMWF
AND THE CANADIAN GLOBAL AS THEY BOTH KEEP THE CENTER OF THE SFC
HIGH WELL W OF THE STATE BACK IN OTTAWA W/A WNW WIND CONTINUING.
THIS WOULD MEAN OVERNIGHT TEMPERATURES WEDNESDAY NIGHT WOULD BE A
BIT WARMER ALTHOUGH WELL BELOW NORMAL AND DAYTIME HIGH TEMPERATURES
FOR THURSDAY WILL BE COLDER AS WELL. ATTM, DECIDED TO BLEND THE
GMOS AND ECMWF FOR MINS WEDNESDAY NIGHT AND FOR MAXES ON THURSDAY
TAKING THIS INTO ACCOUNT.
THINGS LOOK TO BE INTERESTING COME FRIDAY INTO SATURDAY AS THE
LAST 2 RUNS OF THE ECMWF SHOW A LOW PRES SYSTEM COMING OUT OF THE
OHIO VALLEY AND MOVING ACROSS THE GULF OF MAINE. THE CANADIAN
GLOBAL INDICATES THE SAME IDEA AND BRING SIGNIFICANT SNOWFALL TO
EASTERN AND DOWNEAST MAINE AND POSSIBLY NORTHERN AREAS. THE GFS IS
WEAKER AND FASTER W/THE SFC LOW AND KEEPS THE LOW FURTHER S. SOME
OF THE INDIVIDUAL MEMBERS OF THE GFS DO SUPPORT THE ECMWF AND
CANADIAN GLOBAL SETUP. THEREFORE, A BLEND OF THE GMOS AND ECMWF
WAS USED FOR THIS TIME FRAME WHICH MEANS AN INCREASE IN POPS TO 40%
AND WENT W/SNOW INSTEAD OF SNOW SHOWERS. DECIDED TO BRING
TEMPERATURES UP AS WELL FOR FRIDAY INTO SATURDAY W/LOWER TEENS
ACROSS THE NORTH AND MID TEENS TO AROUND 20 CENTRAL AND DOWNEAST.
IT WILL INTERESTING TO SEE HOW THE LATER RUNS TREAT THIS POTENTIAL
SYSTEM.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR CONDITIONS EARLY IN SNOW SQUALLS THEN VFR
CONDITIONS LATER TONIGHT INTO MONDAY.
SHORT TERM: VFR EXPECTED MONDAY INTO TUESDAY WITH THE EXCEPTION
OF KBHB AND POSSIBLY KBGR TUE AS -SN MAY PRODUCE A PERIOD OF
MVFR/IFR. A FEW PATCHES OF HIGHER END MVFR MAY BE FLOATING AROUND
IN THE COLD AIR IN THE NORTH WED-THU...BUT VFR SHOULD BY FAR BE
THE PREVAILING CONDITION.
&&
.MARINE...
NEAR TERM: EXPECT WINDS TO GRADUALLY BECOME OFF-SHORE LATER
TONIGHT. GRADIENT SLACKENS OFF BEFORE EXTREMELY COLD AIR GETS OVER
COASTAL WATERS SO NOT ENOUGH MIXING TO GET STORM WINDS TO SURFACE.
FOR WAVES: SOUTHWEST FETCH WILL END AS WINDS BECOME OFFSHORE. WAVE
HEIGHTS COULD TOP OFF AROUND 15 FEET BEFORE FETCH ENDS.
SHORT TERM: A SMALL CRAFT ADVISORY WILL LIKELY NEED TO CONTINUE
INTO AT LEAST MONDAY MORNING BEFORE THE WIND DIMINISHES BELOW
ADVISORY LEVELS BY AFTERNOON. ANOTHER PERIOD OF SCA LEVEL WINDS
POSSIBLE BY LATE MONDAY NIGHT AS LOW PRESSURE PASSES SOUTH OF THE
WATERS. THERE WILL PROBABLY BE ENOUGH OF A PRESSURE GRADIENT IN
THE WAKE OF THE LOW AS HIGH PRESSURE BEGINS TO BUILD TOWARD THE
WATERS FOR BORDERLINE SCA WIND RIGHT THROUGH THURSDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY UNTIL 1 AM EST MONDAY FOR MEZ001>006-010-011-
015>017-029>032.
WIND CHILL ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR MEZ002-
004>006-010.
WIND CHILL WARNING FROM 1 AM TO 1 PM EST MONDAY FOR MEZ001-003.
MARINE...GALE WARNING UNTIL 7 AM EST MONDAY FOR ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...FITZSIMMONS
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/FITZSIMMONS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 PM EST SUN JAN 20 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A HIGH AMPLITUDE PATTERN
OVER NAMERICA WITH A RIDGE ALONG THE W COAST THRU AK AND A DEEP TROF
COVERING MUCH OF CNTRL/ERN CANADA INTO THE NCNTRL CONUS/GREAT LAKES.
BEHIND LAST NIGHTS SHORTWAVE PASSAGE...INCREASINGLY COLDER ARCTIC
AIR IS FLOWING INTO THE AREA. LATEST RUC ANALYSIS SHOWS 850MB TEMPS
OF -22 TO -24C OVER UPPER MI/LAKE SUPERIOR. UPSTREAM 850MB TEMPS ON
12Z ROABS WERE -25C/-26C/-27C AT KINL/CWPL/CYQD RESPECTIVELY.
FARTHER UPSTREAM...POOL OF SUB -30C AIR AT 850MB IS JUST NW OF CYQD
AS 00Z RAOB AT CYSM SHOWED -34C AT 850MB. THAT CORE OF ARCTIC AIR
WILL BE SETTLING INTO THE UPPER LAKES MON/MON NIGHT BEHIND SHORTWAVE
CURRENTLY DROPPING SSE THRU MANITOBA. ANOTHER WEAKER SHORTWAVE IS
PASSING THRU THE UPPER GREAT LAKES ATTM. HOWEVER...WAVE HAS HAD NO
DISCERNIBLE INFLUENCE ON LES PER RADAR IMAGERY. MOST INTENSE LES
BAND IS STREAMING INTO WRN ALGER COUNTY AS LAND BREEZE COMPONENT
STRENGTHENS CONVERGENCE OFF MARQUETTE COUNTY. TO THE W...WIND
PARALLEL LES BANDS ARE STREAMING INTO WRN UPPER MI. WEBCAMS SHOW
HIGHLY VARIABLE VIS AS -SHSN PASS. SINCE ARCTIC AIR HAS PUSHED DGZ
TO NEAR THE SFC...SNOWFLAKE SIZE IS SMALL...MAKING THE -SHSN VERY
EFFECTIVE AT REDUCING VIS. THIS IS ALSO KEEPING NEW SNOW
ACCUMULTIONS ON THE LIGHT SIDE OVER THE W.
AFOREMENTIONED SHORTWAVE IN MANITOBA WILL DROP ACROSS THE UPPER
LAKES OVERNIGHT TONIGHT THRU MON MORNING. FORCING ASSOCIATED WITH
WAVE PER DEEP LAYER QVECTOR CONVERGENCE WILL GIVE A BOOST TO LES
TONIGHT THRU MID MORNING MON AS MOISTURE DEPTH INCREASES AND
INVERSION RISES TO AROUND 10KFT. NORMALLY WITH SUCH SYNOPTIC
ENHANCEMENT...WOULD BE CONCERNED ABOUT A SIGNIFICANT INCREASE IN HVY
LES/SNOW ACCUMULATIONS. HOWEVER...WITH INCREASINGLY COLDER AIR
CONTINUING TO PUSH DGZ TOWARD THE SFC OR MORE LIKELY ELIMINATING IT
ALTOGETHER...SNOW ACCUMULATIONS WILL BE LIMITED BY SMALL SNOWFLAKE
SIZE. ONLY AREAS LIKELY TO SEE MORE SIGNIFICANT SNOW ACCUMULATIONS
WILL BE THOSE THAT ARE IMPACTED BY LES WITHIN STRONGER CONVERGENCE
ZONES AS THE CONVERGENCE WILL PROVIDE AN OPPORTUNITY FOR MORE
SIGNIFICANT LAKE MODERATION AND THUS POSSIBLY RAISE DGZ INTO A
PORTION OF THE CONVECTIVE LAYER. THOSE ENHANCED CONVERGENCE ZONES
WILL BE DIFFICULT TO PIN DOWN EXACTLY...BUT THERE SHOULD BE 2 OR 3.
ONE SHOULD OCCUR IN ONTONAGON COUNTY...PROBABLY AROUND THE VCNTY OF
THE PORCUPINE MTNS DUE TO STRENGTHENING LAND BREEZE OFF NW WI. THE
OTHERS SHOULD BE IN ERN ALGER COUNTY AND A PORTION OF LUCE COUNTY
DUE TO STRENGTHENING LAND BREEZES OFF MARQUETTE/WRN ALGER COUNTY AND
ALSO OFF ONTARIO. ALL HIGH RES MODEL GUIDANCE POINT TOWARD THE
PROGRESSING LAND BREEZES OVER SCNTRL/ERN LAKE SUPERIOR LEADING TO
EITHER MESO LOW DEVELOPMENT OR SHARP SFC TROFFING SOMEWHERE IN THE
AREA BTWN GRAND MARAIS/CARIBOU ISLAND AND WHITEFISH PT. IF A MESO
LOW DEVELOPS FAR ENOUGH OFFSHORE...IT`S POSSIBLE MOST OF THE LES
WILL ALSO SHIFT OFFSHORE. IF A SHARP CONVERGENCE ZONE DEVELOPS...
MDT/HVY LES COULD STREAM ONSHORE INTO A SMALL PART OF ERN ALGER/NW
LUCE FOR SEVERAL HRS. WITH PASSAGE OF SHORTWAVE...AT SOME POINT MON
MORNING/EARLY AFTN...THE SHARP SFC TROF/MESO LOW WILL BE PUSHED
ONSHORE. GIVEN THE UNCERTAINTY ON THE MESOSCALE DETAILS...WILL
CONTINUE TO HIGHLIGHT ERN ALGER/NRN LUCE CLOSE THE LAKE FOR GREATEST
ACCUMULATIONS TONIGHT/MON WITH POSSIBLE LOCALIZED 6-11 INCH AMOUNTS.
IF SOMETHING SETS UP AND REMAINS STATIONARY...COULD EASILY SEE OVER
A FOOT OF SNOW. OVER THE W...BITTER COLD ARCTIC AIR IS MORE LIKELY
TO ELIMINATE DGZ ALTOGETHER...RESULTING IN VERY SMALL SNOWFLAKES AND
LIMITING SNOW ACCUMULATIONS TO PROBABLY NOTHING MORE THAN 1-2 TO
PERHAPS 3 INCHES PER 12HR PERIOD. LOCALIZED ACCUMULATIONS OF MAYBE
4-5 INCHES WILL BE POSSIBLE IN THE EXPECTED CONVERGENCE ZONE IN
ONTONAGON COUNTY. RATHER THAN SNOW ACCUMULATIONS...THE BIGGER
CONCERN WILL BE VERY LOW VIS AS THE SMALL SNOWFLAKES WILL BE
EXTREMELY EFFECTIVE AT REDUCING VISIBILITY. MAY END UP WITH VERY LOW
VIS/NEAR WHITE-OUT CONDITIONS WHENEVER SNOW SHOWERS PASS DUE TO THE
CONSIDERABLE AMOUNT OF FINE SNOWFLAKES IN THE AIR. THIS TYPE OF FINE
SNOW IS ALSO VERY EASILY BLOWN ABOUT BY VEHICLES...SO VIS ON ROADS
WILL BE ESPECIALLY LOW IN THE VCNTY OF OTHER VEHICLES...MAKING
TRAVEL DANGEROUS DESPITE THE LACK OF SIGNIFICANT SNOW ACCUMULATIONS.
CONSIDERING VIS IMPACTS RATHER THAN SNOW IMPACTS...WILL BE ISSUING A
WINTER WX ADVY FOR ONTONAGON/HOUGHTON/KEWEENAW THRU TUE MORNING TO
HIGHLIGHT VERY POOR VIS IN SHSN AND ALSO TO COVER WIND CHILLS WHICH
WILL BE FALLING TO AROUND THE WIND CHILL ADVY CRITERIA OF -25F.
OTHER CONCERN TONIGHT/MON WILL BE THE BITTER COLD AIR. POOL OF SUB
-30C AIR AT 850MB ADVECTING INTO THE UPPER LAKES MON SUGGESTS MOST
OF THE W HALF OF UPPER MI AWAY FROM IMMEDIATE LAKE SUPERIOR
INFLUENCE WILL STAY BLO ZERO DURING THE DAY MON. IN FACT...IT MAY BE
A STRUGGLE TO RISE MUCH ABOVE -10F ACROSS GOGEBIC COUNTY WHERE LAKE
MODERATION WILL BE LEAST. OTHERWISE...SINGLE DIGITS BLO ZERO SHOULD
BE THE RULE FOR HIGHS OVER THE W MON. WHILE IT`S OFTEN TOUGH TO KEEP
WINDS AOA THE 10MPH THRESHOLD AT NIGHT...CAA MAY BE ENOUGH TO KEEP
WINDS UP SUFFICIENTLY TO SATISFY WIND CHILL CRITERIA LATER TONIGHT.
HAVE EXPANDED WIND CHILL ADVY TO COVER ROUGHLY THE W HALF OF UPPER
MI OUTSIDE OF AFOREMENTIONED WINTER WX ADVY AREA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
AGREEMENT REMAINS GOOD IN THE LARGE SCALE PATTERN FOR THE UPCOMING
WEEK. MODELS ARE NOW EVEN IN OKAY AGREEMENT IN THEIR HANDLING OF
BREAKING DOWN THE DEEP TROUGH OVER THE AREA TO START THE WEEK AND
RESULTING SFC LOW MOVING FROM CENTRAL PLAINS ACROSS THE OHIO VALLEY
THURSDAY INTO FRIDAY.
BY LATE MONDAY GRIP OF COLD WILL BE IN FULL FORCE WITH H85 TEMPS
NEAR -30C OVER FAR WEST AND H95 TEMPS BLO -20C. NO REAL CHANGE TO
EXPECTED MSLP PATTERN WITH LAKE INDUCED TROUGHING AS FAR NORTH AS
EASTERN LK SUPERIOR WHILE HIGH PRESSURE IS CENTERED FROM SOUTHERN
SASKATCHEWAN INTO SOUTHERN MN AND IOWA. RESULT IS PERSISTENT
UNIDIRECTIONAL NW FLOW SFC-H5 ALLOWING LK EFFECT TO CONTINUE. AS IT
HAS APPEARED LAST COUPLE DAYS...MOST CONCENTRATED AND HEAVIEST LK
EFFECT WILL BE OVER FAR NORTHEAST CWA ALONG LK SUPERIOR...EAST OF
MUNISING TO NORTH OF SENEY AND NEWBERRY. AVAILABLE HIGHER RESOLUTION
MODELS STILL PEGGING QPF AMOUNTS OVER 0.20 INCH/12 HR FOR MON NIGHT
AND TUESDAY AND TUESDAY NIGHT. NO DOUBT CONVERGENCE WILL BE
MAXIMIZED DUE TO LARGE SCALE LAKE INDUCED TROUGHING AND ASSOCIATED
MESOLOW FORMING OVER SOUTHEAST LK SUPERIOR DUE TO LAND BREEZES OFF
UPR MICHIGAN AND ONTARIO. AS ALLUDED TO IN SHORT TERM DISCUSSION...
EXACTLY WHERE HEAVIER SNOW BANDS TIED TO THIS MESOSCALE FEATURE SET
UP IS HARD TO PIN DOWN.
MAIN ADJUSTMENT TO QPF/SNOW WAS TO KEEP HIGHER AMOUNTS CLOSER TO
SHORE THAN WHAT MODELS SHOW AS USUALLY LAND BREEZE DOMINATED
CONVERGENCE ZONE ENDS UP CLOSER TO THE LAKE THAN MODELS PORTRAY.
GIVEN THE VERY COLD AIRMASS...SLR/S WILL BE LESS THAN 15:1. OUTSIDE
OF AREAS WHERE STRONGEST CONVERGENCE/MOISTURE FLUXES OCCUR SLR/S
PROBABLY END UP MORE TOWARD 10:1 AS VERY FINE SNOWFLAKES DOMINATE.
SNOW AMOUNTS LIKELY END UP 3-5 INCHES EVERY 12 HRS UNDER DOMINATE
BAND IN THE EAST...BUT FOR REST OF AREAS FAVORED BY NW FLOW ALONG LK
SUPERIOR EXPECT JUST A FEW INCHES EVERY 12 HRS. DUE TO MODERATE SNOW
AMOUNTS SNOW AND POOR VSBY ALONG WITH POSSIBILITY OF DOMINATE BAND
ENHANCING SNOW AMOUNTS...COORD WITH SHORT TERM FORECASTER AND
EXTENDED LK EFFECT SNOW WARNING FOR EASTERN AREAS THROUGH 12Z
TUESDAY. FOR MOST LOCATIONS NEAR LK SUPERIOR IT WILL BE THE POOR VSBY
INSTEAD OF THE SNOW AMOUNTS THAT WILL BE THE HIGHER IMPACT ISSUE.
FREQUENT WHITEOUT CONDITIONS ARE EXPECTED AS THE SMALL SNOW FLAKES
FALLING WITH EVEN 10-20 MPH WINDS WILL BE VERY PROFICIENT IN LEADING
TO LOWER VSBY.
BITTER COLD WIND CHILLS ARE THE OTHER ISSUE EARLY THIS WEEK. AS IT
APPEARED YDY...TIGHTEST PRESSURE GRADIENT IS PRESENT TO BEGIN THE
LONG TERM BUT IT GRADUALLY RELAXES BY TUESDAY MORNING AND EVEN
FURTHER BY WEDNESDAY MORNING. EXPECT MIN TEMPS MONDAY NIGHT TO FALL
LESS THAN 10 BLO OVER A MAJORITY OF WEST HALF OF UPR MICHIGAN WITH
WIND CHILL READINGS DOWN TO 25-30 BLO ZERO. POSSIBLE THAT WINDS MAY
NOT TECHNICALLY REACH CRITERIA /SUSTAINED AT 10 MPH/ BUT IT IS
CERTAINLY CLOSE ENOUGH TO ISSUE A HEADLINE. AFTER COORD WITH SHORT
TERM FORECASTER...DECIDED TO ISSUE CATCH ALL WINTER WEATHER ADVY
OVER WESTERN TIER OF CWA FOR LK EFFECT SNOW/POOR VSBY AND THE BITTER
COLD WIND CHILLS. THIS HEADLINE WILL RUN THROUGH MIDDAY TUESDAY.
ELSEWHERE OVER WEST HALF OF UPR MICHIGAN...GOING TO ISSUE WIND CHILL
ADVY THROUGH MIDDAY TUESDAY. FURTHER REFINEMENTS MAY BE NEEDED TO
HEADLINES AS WE GET INTO MONDAY/TUESDAY...BUT THIS WILL BE OUR
STARTING POINT.
WORKING INTO TUESDAY NIGHT AND WEDNESDAY CONDITIONS CHANGE A BIT.
MAIN CHANGE IS BLYR WINDS BACKING MORE WSW TUESDAY NIGHT AND H925
WINDS BACKING WESTERLY. CHANGE IN WIND WILL PUSH ONGOING LK EFFECT
AND CLOUDS OVER THE WEST FARTHER TO THE NORTH. LK EFFECT STAYS IN
PLACE MOSTLY OVER THE EAST...STILL FALLING MODERATE AT TIMES...AS
THE STATIONARY MESOLOW REMAINS PRIMARY FEATURE DRIVING THE SNOW
THERE. THINKING THAT WITH WEAK PRESSURE GRADIENT AND LOSS OF CLOUDS
SHOULD ALLOW FOR WINDS OVER INTERIOR TO BECOME CALM AND PRIME
RADIATIONAL COOLING TO DEVELOP. LOWERED MIN TEMPS TOWARD LOWEST
GUIDANCE NUMBERS AROUND 20 BLO ZERO. MAY EVEN SEE LOWER TEMPS AT THE
FAVORED COLD SPOTS...BUT WILL JUST TREND IN THE COLDER DIRECTION FOR
NOW. ONLY CONCERN IN MIN TEMP FCST IS POSSIBLE INCREASING CLOUDS
ALOFT AHEAD OF ANOTHER TROUGH THAT DROPS IN ON WEDNESDAY. THINK
THOSE MID CLOUDS WILL HOLD OFF LONG ENOUGH TO ALLOW TEMPS TO TANK ON
TUESDAY NIGHT.
AS UPPER TROUGH BEGINS TO LOSE GRIP OVER AREA ON WEDNESDAY...MODELS
SHOWING SHORTWAVE DIPPING FROM NORTHERN PLAINS ON WEDNESDAY NIGHT TO
ACROSS LOWER GREAT LAKES LATER THURSDAY. MAJORITY OF SYNOPTIC SNOW
FROM THE SYSTEM PROBABLY MISSES UPR MICHIGAN...PERHAPS JUST TO THE
SOUTH THOUGH ACROSS WI AND LOWER MICHIGAN. INDICATION IS THAT FLOW
WILL BE SPLIT AND THE SOUTHERN SHORTWAVE DRIVES THE MAIN SYSTEM TO
THE SOUTH...BUT THERE IS ALSO NORTHERN STREAM WAVE DROPPING ACROSS
UPR LAKES THURSDAY NIGHT INTO FRIDAY. THIS MAY KEEP AN INVERTED SFC
TROUGH WELL TO NORTHWEST OF MAIN SFC LOW WHICH COULD LEAD TO SCT
SNOW SHOWERS OVR UPR LAKES ENHANCED FURTHER BY ONSHORE FLOW OFF LK
SUPERIOR. CONSENSUS POPS LOOKED OKAY...BUT DID INCREASE THEM
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT NEAR LK SUPERIOR. BASED ON
MSLP AND H85 RH/TEMPS...LK EFFECT CONTINUES THROUGH FRIDAY AND
EVEN INTO SATURDAY OVER THE EASTERN CWA...THOUGH INCREASING LOW-MID
LEVEL RIDGING WILL LEAD TO INCREASINGLY HOSTILE CONDITIONS FOR THE
LK EFFECT.
HEIGHTS FURTHER FLATTEN OUT THROUGH NEXT WEEKEND LEADING TO WARMER
AIR SPILLING ACROSS NORTHERN PLAINS AND UPR LAKES. COULD BE WARM AIR
ADVECTION TYPE SYSTEM SNOW BUT GFS AND ECMWF DIFFER ON TRACK OF
SHORTWAVE AND SFC TROUGH TO ENHANCE THAT SNOW POTENTIAL /ECMWF
FARTHER NORTH WHILE GFS MOVES FOCUS ACROSS UPR MICHIGAN/ SO WILL NOT
ALTER THE SLIGHT CHANCES THAT CONSENSUS GAVE FOR POPS. AFTER A
BITTER COLD START TO THE WEEK...APPEARS THAT TEMPS TO END THE WEEK
INTO NEXT WEEKEND WILL SHOW WARMING TREND WITH READINGS CLOSE TO
NORMAL BY NEXT SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 641 PM EST SUN JAN 20 2013
WESTERLY TO NORTHWESTERLY FLOW WILL CONTINUE TO BRING LAKE EFFECT
SNOW TO MAINLY THE CMX AND IWD TAF SITES. CEILINGS ARE EXPECTED TO
REMAIN AT OR ABOVE 2KFT FOR ALL TAF SITES WITH THE EXCEPTION OF CMX
WHERE CEILINGS MAY FALL NEAR 1KFT UNDER THE HEAVIER LES BANDS. LAKE
EFFECT SNOW IS EXPECTED TO INCREASE ONCE AGAIN THIS EVENING AND
DURING THE OVERNIGHT HOURS...ESPECIALLY NEAR THE CMX TAF SITE. HAVE
KEPT REDUCED VISIBILITY IN THE CMX TAF AS WINDS ARE EXPECTED TO
INCREASE ALONG WITH THE LES...WHICH WOULD ENHANCE THE BLOWING SNOW
POTENTIAL. IWD WILL LIKELY SEE OCCASIONAL SNOW SHOWERS BUT THEY
SHOULD REMAIN LIGHTER THAN THE CMX TAF SITE...THEREFORE KEPT
VISIBILITY TREND GOING WITH ONLY SLIGHT REDUCTION. IF A HEAVIER BAND
PASSES OVER THE IWD TAF SITE WOULD NOT BE SURPRISED TO SEE A FEW
OBSERVATIONS IN THE 3 TO 5 MILE RANGE. NORTHWESTERLY WINDS ARE NOT
PARTICULARLY FAVORABLE FOR LES OVER THE KSAW TAF SITE...THEREFORE
HAVE KEPT THE MENTION OUT OF THE TAF BUT IT IS NOT OUT OF THE
QUESTION TO HAVE A FEW LIGHT SNOW SHOWERS PASS OVER KSAW BRIEFLY
REDUCING VISIBILITY. AS PRESSURE GRADIENT INCREASES BETWEEN HIGH
PRESSURE TO THE WEST AND WEAK LOW PRESSURE TO THE EAST...EXPECT
WINDS TO INCREASE AT EACH TAF SITE BY MONDAY MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 PM EST SUN JAN 20 2013
NW WINDS OF 15-30KT WILL DOMINATE LAKE SUPERIOR TONIGHT THRU MON AS
INCREASINGLY COLDER ARCTIC AIR FLOWS OVER THE LAKE. ONLY EXCEPTION
WILL BE OVER THE FAR E WHERE LAND BREEZES OFF UPPER MI AND ONTARIO
MAY YIELD A SHARP SFC TROF OR MESOLOW. AS A RESULT...WINDS MAY SHIFT
TO A LIGHTER OFFSHORE DIRECTION EAST OF GRAND MARAIS TONIGHT WHILE
LAND BREEZE E TO NE WINDS PUSH OVER THE LAKE FROM ONTARIO INTO THE
AREA S OF CARIBOU ISLAND. SFC TROF/MESO LOW WILL MOVE S OR SE MON...
BRINGING STRONGER N OR NW WINDS BACK TO THAT AREA. HVY FREEZING
SPRAY WILL CONTINUE UNDER BITTER COLD AIR FLOWING INTO THE AREA.
EXPECT WINDS TO STAY IN THE 20 TO 30 KT RANGE THROUGH MIDDLE OF WEEK
THEN WINDS FINALLY RELAX AS HIGH PRESSURE BEGINS TO BUILD ACROSS REGION.
HEAVY FREEZING SPRAY WILL SUBSIDE...BUT NOT UNTIL WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY FROM 1 AM EST /MIDNIGHT CST/ MONDAY TO 1 PM
EST /NOON CST/ TUESDAY FOR MIZ004-005-009>011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KEC
MARINE...ROLFSON/JLA
AREA FORECAST DISCUSSION
NWS DULUTH MN
336 PM CST SAT JAN 19 2013
.SHORT TERM.../NOW - SUNDAY NIGHT/
THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF
STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A
STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE
GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES
TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE
AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS
MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE
TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS
SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL
MINNESOTA AND NORTHWESTERN WISCONSIN.
AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER
PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH
WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE
NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO
MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW
FA.
THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST.
THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE
TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS
EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE
EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE
WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS
EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS
OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS
UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT
DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z
TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM
SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH
03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING
TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND
INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW
SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY
THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS
DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO
THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF
THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY
MORNING.
SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY
ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO
DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE
SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE
NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL
VALUES APPROACHING 50 DEGREES BELOW ZERO.
.LONG TERM.../MONDAY - FRIDAY NIGHT/
MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR
PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING
THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL
VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY
MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE
LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON
THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A
PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE
ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL.
&&
.AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN
GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS
WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS
COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD.
HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH
TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT
EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z.
&&
.POINT TEMPS/POPS...
DLH -12 0 -21 -9 / 10 10 10 10
INL -19 -5 -30 -12 / 10 10 10 10
BRD -12 1 -22 -10 / 10 10 10 0
HYR -5 3 -18 -7 / 20 10 10 10
ASX -1 6 -13 -4 / 60 30 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO NOON CST SUNDAY
FOR MNZ010>012-018>021-025-026-033>038.
WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ033-034-036-038.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021.
WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ006.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR
WIZ001>004-006>009.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
306 PM CST SAT JAN 19 2013
.DISCUSSION...
FORECAST CONCERNS FOR THE 7 DAY PERIOD AHEAD ARE MAINLY CONFINED
TO THE NEXT 48 HOURS. THE ARCTIC BOUNDARY IS PASSING THROUGH THE
CWA AS FORECAST THIS AFTERNOON. SUSTAINED WINDS NEAR 30 MPH WITH
GUSTS REACHING 55 MPH HAVE BEEN COMMON IN THE WAKE OF THE FRONT.
THE BOUNDARY IS MOVING THROUGH THE TWIN CITIES AT THIS TIME. THE
FRONT WILL BE PAST KEAU TO THE IA BORDER BY 5 PM. THE WIND
ADVISORY WILL REMAIN IN EFFECT CWA-WIDE THROUGH 9 PM. SOME FLURRY
ACTIVITY CAN NOT BE RULED OUT AS WELL IN THE CLOUD STREETS THAT
STRETCH BACK TO THE CANADIAN BORDER. OF GREATER CONCERN...WE
DEFINITELY HAVE DRIFTING SNOW ACROSS THE NW CWA AROUND KAXN BASED
ON MULTIPLE WEB CAMS. THE VISIBILITY IS NOT TOO BAD...BUT IT DOES
BECOME MUCH WORSE NW OF OUR CWA TOWARDS FERGUS FALLS AND FARGO.
HAVE ADDED BLOWING SNOW TO THE GRIDS FOR THE LATE AFTERNOON/
EVENING HOURS TO AREAS WEST OF A KLXL TO KOVL LINE ALONG WITH
ISSUING AN SPS.
AS THE EVENING PROGRESSES AND TEMPERATURES CONTINUE TO
PLUMMET...WIND CHILL VALUES BECOME CRITICAL ACROSS CENTRAL MN AND
PARTS OF WEST CENTRAL WI. THE CURRENT WIND CHILL ADVISORIES LOOK
OKAY WITH THE ONE ACROSS CENTRAL MN BEGINNING AFTER 9 PM AND IN
WEST CENTRAL WI AFTER MIDNIGHT. AT THIS POINT...THE WIND CHILL
VALUES OF 25 BELOW ARE MOST WIDESPREAD ACROSS CENTRAL MN
OVERNIGHT AND SUNDAY MORNING.
A DISTURBANCE MOVING SOUTHEAST ACROSS THE PLAINS ON SUNDAY WILL
BRING A PERIOD OF SNOW THAT WILL BRUSH WEST CENTRAL THROUGH SOUTH
CENTRAL MN. THE MODELS HAVE BEEN PRETTY CONSISTENT WITH THIS
FEATURE FOR THE PAST FEW DAYS ALTHOUGH A SLIGHT SOUTHWEST DRIFT
HAS OCCURRED WITH TIME. THE SREF SHOWS 18 OF 21 MEMBERS MEASURING
ALONG AND SOUTH THE MN RIVER VALLEY. AS A RESULT...RAISED POPS IN
THESE AREAS TO 60-80 PERCENT BASED ON THE ABOVE ALONG WITH THE MID
LEVEL FRONTOGENESIS AND THE LOW CONDENSATION PRESSURE DEFICITS/
ADIABATIC OMEGA MOVING THROUGH ON THE 280K SURFACE. CARIBOU SNOW
TECHNIQUE PRETTY CONSISTENT AS WELL BETWEEN THE NAM/GFS AND SREF
ON SNOW AMOUNTS BEING AROUND A HALF INCH...ALTHOUGH THE GRIDS
REFLECT FROM A HALF INCH TO NEARLY AN INCH. ITS INTERESTING TO NOTE
THAT THE SATURATED COLUMN ACROSS THE SW CWA ON SUNDAY IS AT OR
BELOW -18 DEG C. THIS WOULD BE MORE PLATES AND COLUMNS WITH THE
DENDRITIC DEVELOPMENT.
THE HEART OF THE ARCTIC AIR WILL BE FROM SUNDAY NIGHT THROUGH
TUESDAY. MORE WIND CHILL PRODUCTS WILL LIKELY BE NEEDED SUNDAY
NIGHT AND MONDAY WITH CURRENT GRIDDED WIND CHILL VALUES IN THE 25
BELOW TO 45 BELOW ZERO RANGE. OVERNIGHT LOWS SUNDAY NIGHT AND
MONDAY NIGHT PRETTY MUCH BETWEEN 10 BELOW AND 20 BELOW ZERO ACROSS
THE CWA. THE HIGHS ON MONDAY ARE STILL PROGGED BELOW ZERO ACROSS
THE ENTIRE CWA.
THERE WILL BE SLOW MODERATION TO THE TEMPERATURES IN THE MID WEEK
PERIOD. THERE ALSO REMAINS A CHANCE OF LIGHT SNOW FROM THURSDAY
INTO FRIDAY AS A PACIFIC SHORT WAVE MOVES THROUGH. ONE OF THE
PROBLEMS SEEN WITH THIS SYSTEM IS THAT THE MODELS ARE TRYING TO
SHOW BOTH NORTHERN AND SOUTHERN STREAM ENERGY. WE COULD END UP
WITH A SPLIT PRECIPITATION PATTERN ACROSS THE UPPER MISSISSIPPI
VALLEY REGION. HENCE...CHANCE POPS CONTINUE WITH LOW CONFIDENCE ON
THE OUTCOME. IT WILL LIKELY TURN COLD AGAIN HEADING INTO NEXT
WEEKEND IN THE WAKE OF THIS SYSTEM WITH BELOW ZERO TEMPERATURES
FOR SATURDAY MORNING.
&&
.AVIATION... /18Z TAF ISSUANCE/
SFC LOW NOW MOVING OVER LK SUPERIOR...WITH THE ARCTIC COLD FRONT
NOW STARTING ON A TEAR SOUTH ACROSS MN. WAS INITIALLY THINKING OF
SCALING GUSTS BACK SOME...SINCE GUSTS ACROSS NRN MN/NODAK WERE
ONLY GUSTING IN THE MID 30S...BUT AS OBS AROUND 1730Z STARTED
ROLLING...STARTED TO SEE GUSTS OVER 40 KTS ACROSS WEST CENTRAL MN
RIGHT BEHIND THE BOUNDARY...SO LEFT BIG GUSTS IN PLACE. STILL
EXPECT A 2 OR 3 HOUR WINDOW WITH SUSTAINED WINDS 30-35 KTS WITH
GUSTS 40 TO 45 KTS IMMEDIATELY BEHIND THE FRONT...BEFORE SUSTAINED
SPEEDS AND GUSTS SETTLE DOWN ABOUT 10 KTS. FRONT ALSO COMING DOWN
WITH MVFR CIGS BETWEEN 010 AND 020. THESE CLOUDS WILL REMAIN IN
PLACE THROUGH THE AFTERNOON...BUT CLEARING IS SEEN MOVING SOUTH
ACROSS NODAK THIS AFTERNOON. CURRENTLY CLOCKING THIS CLEARING
MOVING SOUTH AT ABOUT 50 KTS...SO A RETURN TO VFR CONDS MAY COME
ABOUT FASTER THAN CURRENTLY INDICATED. THIS TREND TO VFR CIGS IS
SUPPORTED BY THE SREF...WHICH HAS MUCH OF THE MPX CWA VFR
OVERNIGHT...BEFORE BRINGING ANOTHER ROUND OF MVFR CIGS IN FROM THE
DAKOTAS LATE TONIGHT. AS FOR WX...THERE WILL BE TWO CHANCES FOR
SNOW. FIRST WILL BE BEHIND THE COLD FRONT THIS AFTERNOON...THOUGH
THIS LOOKING LESS LIKELY OUTSIDE OF CENTRAL MN. RAP SOUNDINGS SHOW
POST FRONTAL CLOUD LAYER REACHING UP INTO THE SNOW GROWTH ZONE
NORTH...BUT AS YOU HEAD TOWARD MSP/EAU...THE POST FRONTAL CLOUD
LAYER IS FORECAST TO BE TOO WARM TO GENERATE ICE CRYSTALS...SO CUT
BACK ON SNOW MENTION OUTSIDE OF CENTRAL MN. SECOND CHANCE WILL
COME TONIGHT AS AN UPPER WAVE MOVES ACROSS AN ELEVATED FRONTAL
BOUNDARY ACROSS SW MN. MOST OF THE SNOW LOOKS TO STAY SW OF MPX
TERMINALS...THOUGH RWF LOOKS TO GET A PERIOD OF -SN IN THE
MORNING.
KMSP...MVFR CIGS ALREADY MOVING INTO THE NW METRO AND SHOULD BE IN
AT MSP WITHIN THE FIRST HOUR. WILL START SEEING GUSTS PICK UP WITH
THE ARRIVAL OF THE CLOUDS...THOUGH GUSTS NEAR 40 KTS ARE TRAILING
THE CLOUDS BY A BIT...THOUGH MAY SEE STRONGER GUSTS SHOW UP A BIT
EARLIER THAN 22Z. ALSO PULLED BACK ON SNOW BASED ON WARMER
FORECAST CLOUD LAYER...BUT LOOKING AT IR...IS A NICE BAND OF
COOLER TOPS MOVING SOUTH ACROSS CENTRAL MN AT THE MOMENT. IF THIS
CAN HOLD TOGETHER...MAY NEED TO MENTION AN IFR VIS MENTION IN -SN
BETWEEN 21Z AND 23Z. SREF HAS A GOOD HANDEL ON CLEARING CURRENTLY
MOVING ACROSS NODAK...SO FOLLOWED IT IN BRINGING VFR CONDITION
BACK IN TONIGHT. SNOW MOVING INTO SW MN LOOKS TO REMAIN WELL SW OF
MSP...BUT CAN NOT RULE OUT A FLURRY OR TWO WITH MVFR CONDS MOVING
BACK IN BY SUNDAY AFTERNOON.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS POSSIBLE EARLY. WINDS NW 10 KTS.
TUE...VFR. WINDS W 5 KTS.
WED...VFR. WINDS SW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS-
FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE
LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM CST SUNDAY
FOR BENTON-DOUGLAS-ISANTI-KANABEC-MILLE LACS-MORRISON-POPE-
SHERBURNE-STEARNS-STEVENS-TODD.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY
FOR ANOKA-CHISAGO.
WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR BARRON-CHIPPEWA-
DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY
FOR BARRON-CHIPPEWA-DUNN-POLK-RUSK-ST. CROIX.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1240 PM CST SAT JAN 19 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
UPDATE...
/ISSUED 1043 AM CST SAT JAN 19 2013/
COUPLE OF CHANGES MADE TO GRIDS THIS MORNING. BIGGEST CHANGE WAS
TO LOWER POPS FOR THIS AFTERNOON...WITH POPS NOW UNDER 50% WITH
SCT SNOW SHOWERS WORDING NOTED. THIS WAS BASED ON FORECAST
SOUNDINGS FROM THE RAP. YES WE ARE STILL SEEING AGGRESSIVE CAA
WITH UNSTABLE LOW LEVEL LAPSE RATES...BUT THERE IS NO SATURATION
NOTED WITHIN THE DENDRITIC GROWTH ZONE. SO DESPITE SEEING
EXTENSIVE CLOUD COVER...DOUBTING WHETHER THERE WILL BE MUCH OF ANY
ACTIVITY BEHIND THE COLD FRONT...WHICH AT 1030AM WAS JUST
BEGINNING TO PUSH INTO THE NRN PORTION OF THE MPX MN CWA.
ONLY OTHER CHANGES WERE MINOR TIMING CHANGES TO WIND SPEED
INCREASE AND TEMP/DEWP DROPS BEHIND THE COLD FRONT. WITH MAIN
FRONT COMING IN A LITTLE SLOWER THAN WHAT WAS EXPECTED THIS
MORNING...DELAYED THE SPEED INCREASE AND TEMP DROPS BY A COUPLE OF
HOURS...BUT STILL LOOKING QUITE BLUSTERY WITH AGGRESSIVE TEMP
DROPS ONCE THE FRONT GOES THROUGH...AS SEEN IN FARGO WHERE IT WENT
FROM 36 AT 14Z DOWN TO 18 AT 16Z...SO LOSING NEARLY 10 DEGS PER
HOUR.
PREV DISCUSSION...
/ISSUED 615 AM CST SAT JAN 19 2013/
BIG CHANGE IN THE WEATHER WILL COMMENCE TODAY. LOCAL WRF MODEL
MEAN DOES INDICATE THE NORTHERN CWA WILL SEE SOME SNOW SHOWERS AS
STRONG COLD FRONT DROPS SOUTHEAST OVER THE AREA. APPEARS FRONT
WILL BE LOCATED JUST NORTH OF KMSP THROUGH 18Z. THEN EXITING THE
FAR SOUTH THROUGH 23Z. STRONG NORTHWEST WINDS DEVELOPING BEHIND
FRONT WITH STRONG CAA PATTERN AND STEEP LAPSE RATES DEVELOPING.
THIS ALONG WITH PV ANOMALY SHOULD BE ENOUGH TO DRIVE 45-50 MPH
WIND GUSTS OVER MUCH OF THE AREA INTO THE AFTERNOON WITH FROPA.
WILL CONTINUE THE WIND ADV FOR THE REGION THROUGH 9 PM. TEMPERATURES
EXPECTED TO TUMBLE RAPIDLY AS WELL AFTER FROPA...INTO THE SINGLE
DIGITS NORTHWEST AND THROUGH THE TEENS IN THE SOUTHEAST. WILL NEED
WIND CHILL ADVISORY FOR NORTHERN PORTION OF THE CWA DURING THE NIGHT
AND SATURDAY MORNING.
COLD AIR DROPS OVER THE AREA THE NEXT SEVERAL DAYS AS 1050MB HIGH
MOVES ACROSS THE DAKOTAS WITH MINUS 28 TO MINUS 30 CELSIUS H85 AIR
MOVING ACROSS THE AREA. ANOTHER WEAK SHORT WAVE MOVES ACROSS THE
AREA SUNDAY AND CONTINUED SOME CHANCE POPS...MAINLY TO THE
SOUTHWEST. THE CORE OF COLDEST AIR TO MOVE THROUGH MONDAY WITH
THE ENTIRE CWA EXPECTED TO REMAIN BELOW ZERO. WIND CHILL
WARNING/ADVISORY WILL MOST LIKELY BE NEEDED AGAIN SUNDAY NIGHT
PERHAPS LINGERING THROUGH MONDAY NIGHT OR TUESDAY MORNING.
MODERATION OF THE ARCTIC AIR THEN TAKES PLACE AFTER TUESDAY.
LONGER TERM MODELS SUGGEST ANOTHER MORE SIGNIFICANT WAVE MOVES
INTO THE REGION THURSDAY INTO FRIDAY WITH ANOTHER SHOT AT SOME
ACCUMULATING SNOW. COLDER AIR FOLLOWS THIS SYSTEM AS WELL...BUT
NOT AS COLD AS THE AIR MOVING IN EARLY IN THE PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
SFC LOW NOW MOVING OVER LK SUPERIOR...WITH THE ARCTIC COLD FRONT
NOW STARTING ON A TEAR SOUTH ACROSS MN. WAS INITIALLY THINKING OF
SCALING GUSTS BACK SOME...SINCE GUSTS ACROSS NRN MN/NODAK WERE
ONLY GUSTING IN THE MID 30S...BUT AS OBS AROUND 1730Z STARTED
ROLLING...STARTED TO SEE GUSTS OVER 40 KTS ACROSS WEST CENTRAL MN
RIGHT BEHIND THE BOUNDARY...SO LEFT BIG GUSTS IN PLACE. STILL
EXPECT A 2 OR 3 HOUR WINDOW WITH SUSTAINED WINDS 30-35 KTS WITH
GUSTS 40 TO 45 KTS IMMEDIATELY BEHIND THE FRONT...BEFORE SUSTAINED
SPEEDS AND GUSTS SETTLE DOWN ABOUT 10 KTS. FRONT ALSO COMING DOWN
WITH MVFR CIGS BETWEEN 010 AND 020. THESE CLOUDS WILL REMAIN IN
PLACE THROUGH THE AFTERNOON...BUT CLEARING IS SEEN MOVING SOUTH
ACROSS NODAK THIS AFTERNOON. CURRENTLY CLOCKING THIS CLEARING
MOVING SOUTH AT ABOUT 50 KTS...SO A RETURN TO VFR CONDS MAY COME
ABOUT FASTER THAN CURRENTLY INDICATED. THIS TREND TO VFR CIGS IS
SUPPORTED BY THE SREF...WHICH HAS MUCH OF THE MPX CWA VFR
OVERNIGHT...BEFORE BRINGING ANOTHER ROUND OF MVFR CIGS IN FROM THE
DAKOTAS LATE TONIGHT. AS FOR WX...THERE WILL BE TWO CHANCES FOR
SNOW. FIRST WILL BE BEHIND THE COLD FRONT THIS AFTERNOON...THOUGH
THIS LOOKING LESS LIKELY OUTSIDE OF CENTRAL MN. RAP SOUNDINGS SHOW
POST FRONTAL CLOUD LAYER REACHING UP INTO THE SNOW GROWTH ZONE
NORTH...BUT AS YOU HEAD TOWARD MSP/EAU...THE POST FRONTAL CLOUD
LAYER IS FORECAST TO BE TOO WARM TO GENERATE ICE CRYSTALS...SO CUT
BACK ON SNOW MENTION OUTSIDE OF CENTRAL MN. SECOND CHANCE WILL
COME TONIGHT AS AN UPPER WAVE MOVES ACROSS AN ELEVATED FRONTAL
BOUNDARY ACROSS SW MN. MOST OF THE SNOW LOOKS TO STAY SW OF MPX
TERMINALS...THOUGH RWF LOOKS TO GET A PERIOD OF -SN IN THE
MORNING.
KMSP...MVFR CIGS ALREADY MOVING INTO THE NW METRO AND SHOULD BE IN
AT MSP WITHIN THE FIRST HOUR. WILL START SEEING GUSTS PICK UP WITH
THE ARRIVAL OF THE CLOUDS...THOUGH GUSTS NEAR 40 KTS ARE TRAILING
THE CLOUDS BY A BIT...THOUGH MAY SEE STRONGER GUSTS SHOW UP A BIT
EARLIER THAN 22Z. ALSO PULLED BACK ON SNOW BASED ON WARMER
FORECAST CLOUD LAYER...BUT LOOKING AT IR...IS A NICE BAND OF
COOLER TOPS MOVING SOUTH ACROSS CENTRAL MN AT THE MOMENT. IF THIS
CAN HOLD TOGETHER...MAY NEED TO MENTION AN IFR VIS MENTION IN -SN
BETWEEN 21Z AND 23Z. SREF HAS A GOOD HANDEL ON CLEARING CURRENTLY
MOVING ACROSS NODAK...SO FOLLOWED IT IN BRINGING VFR CONDITION
BACK IN TONIGHT. SNOW MOVING INTO SW MN LOOKS TO REMAIN WELL SW OF
MSP...BUT CAN NOT RULE OUT A FLURRY OR TWO WITH MVFR CONDS MOVING
BACK IN BY SUNDAY AFTERNOON.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS POSSIBLE EARLY. WINDS NW 10 KTS.
TUE...VFR. WINDS W 5 KTS.
WED...VFR. WINDS SW 5 KTS.
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS-
FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE
LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM CST SUNDAY
FOR BENTON-DOUGLAS-ISANTI-KANABEC-MILLE LACS-MORRISON-POPE-
SHERBURNE-STEARNS-STEVENS-TODD.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY
FOR ANOKA-CHISAGO.
WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR BARRON-CHIPPEWA-
DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY
FOR BARRON-CHIPPEWA-DUNN-POLK-RUSK-ST. CROIX.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1100 AM CST SAT JAN 19 2013
.DISCUSSION...
COLD FRONT HAS REACHED ALL BUT THE SOUTHERN VALLEY AND ADJACENT
PORTIONS OF WEST CENTRAL MN WHERE 16 UTC OBSERVATIONS SHOWED
TEMPERATURES STILL IN THE UPPER 20S AND LOW 30S. HIGHS FOR THE DAY
HAVE ALREADY OCCURRED AND WILL SEE FALLING TEMPERATURES THROUGH
THE LATE MORNING AND AFTERNOON HOURS.
REGIONAL RADARS SHOWING WEAK STREAMERS IN WAKE OF THE FRONT...SO
ADDED CHANCE POPS THROUGH THE MID-AFTERNOON FOR POSSIBLY A DUSTING
TO A TENTH OF AN INCH ACCUMULATION. REALISTICALLY...WINDS WILL
MAKE MEASURING ANY NEW SNOWFALL NEARLY IMPOSSIBLE.
STRONGEST WIND SO FAR HAS BEEN CONFINED TO THE HIGHER TERRAIN FROM
ROLLA TO RUGBY TO HARVEY TO COOPERSTOWN WHERE GUSTS AT TIMES HAVE
EXCEEDED 50 MPH. FARTHER SOUTH AND EAST...GUSTS HAVE BEEN IN THE
35 TO 45 MPH RANGE. LATEST RAP STILL SHOWING 925 HPA WINDS AT OR
ABOVE 40 KTS THROUGH THE AFTERNOON...SO AS MIXED LAYER DEEPENS..
STILL EXPECT WINDS TO INCREASE FOR THE NEXT FEW HOURS BEFORE
DECREASING LATER THIS AFTERNOON. SINCE THE EVENT IS STILL
UNFOLDING...WILL NOT MAKE ANY CHANGES TO HIGH WIND WARNING/WIND
ADVISORY HEADLINES AT THIS TIME.
REDUCTIONS IN VISIBILITY AT OR BELOW A QUARTER OF A MILE ARE
WIDESPREAD ACROSS PORTIONS OF THE DEVILS LAKE BASIN AND NORTHERN
VALLEY. THE WORST CONDITIONS WILL CONTINUE ACROSS OPEN COUNTRY
AWAY FROM CITIES AND SHELTERED AREAS. MOST VISIBILITY ISSUES ARE
DUE TO BLOWING AND DRIFTING SNOW ON THE GROUND...BUT CANNOT RULE
OUT RAPID WORSENING CONDITIONS IF A BRIEF SNOW STREAMER MOVES
OVERHEAD. CURRENT BLIZZARD WARNING/WINTER WEATHER ADVISORY LOOKS
GOOD WITH NO CHANGES PLANNED.
&&
.AVIATION...
MVFR CIGS HAVE SLIPPED SOUTH AND EAST AHEAD OF DRY PUNCH...HAVING
REACHED KFAR BY MID MORNING. VENTURI EFFECT HAS SHIFTED VALLEY WINDS
TO A MORE NORTHERLY DIRECTION AT INCREASED SPEEDS...WILL CONTINUE
FOR A TIME BEFORE BACKING TO NORTHWEST FOR THE AFTERNOON. OTHERWISE...
STILL EXPECTING LOWEST VSBY VICINITY OF KDVL LATE MORNING...
AFFECTING NORTHERN VALLEY SITES BY EARLY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 340 AM CST SAT JAN 19 2013/
DISCUSSION...FORECAST CHALLENGE CONCERNS ONGOING HEADLINES WITH
STRONG ARCTIC COLD FRONT. MODELS IN GOOD AGREEMENT AND WILL USE
BLEND FOR FORECAST.
VERY CHALLENGING FORECAST FOR TODAY AND WILL FOCUS DISCUSSION
MAINLY TO THE VERY SHORT TERM . SURFACE LOW OVER NORTHERN VALLEY TO
PROPAGATE ESE AND DEEPEN BEFORE REACHING THE GREAT LAKES THIS
EVENING. ASSOCIATED STRONG ARCTIC COLD FRONT TO PLOW THROUGH
FORECAST AREA TODAY. MAIN CONCERN WITH FEATURE WILL BE STRONG
WINDS IN WAKE OF COLD FRONTAL PASSAGE AND POTENTIAL FOR BLIZZARD
CONDITIONS AND EVENTUAL HAZARDOUS WIND CHILLS WITH FALLING
TEMPERATURES. WILL SPLIT DISCUSSION TO AREAS RECEIVING PARTICULAR
HEADLINES.
NORTHERN VALLEY INTO DVL BASIN. CURRENT BLIZZARD WARNING LOOKING
GOOD. THIS AREA HAS DEEPEST SNOW COVER AND AVAILABLE FRESH SNOW TO
BLOW AROUND. CURRENT BAND OF -SN ALONG AND NORTH OF SURFACE LOW
SHIFTING INTO FAR NORTHERN MN AND WILL CONTINUE INTO THE MORNING
HOURS. MODEL SOUNDINGS INDICATING MIXED LAYER TO AROUND 900MB WITH
30KTS TO MIX AND SHOULD BE EFFICIENT WITH STRONG COLD ADVECTION.
WHILE GROUND BLIZZARD CONDITIONS NOT EXPECTED WITHIN TOWNS HAVE
EXPANDED BLIZZARD WARNING INTO GRAND FORKS AND WEST POLK COUNTIES
WHERE NORTHERN PARTS OF THE COUNTY AND AREAS WEST OF VALLEY RIDGE
HAVE BETTER POTENTIAL FOR GROUND BLIZZARD CONDITIONS.
REMAINDER OF AREAS WEST OF VALLEY. WINDS ALOFT STRONGER AND MIXED
LAYER DEEPER. LOCAL CHECKLIST INDICATING POTENTIAL FOR STRONGEST
WINDS THIS AREA. TEMPERATURES HAVE BEEN MILD CURRENTLY AND IN THE
PAST WEEK ALONG WITH -RA LAST WEEKEND WHICH HAS CRUSTED SNOW PRETTY
WELL. A FEW SNOW SHOWERS POSSIBLE WITH FROPA HOWEVER SHOULD NOT
GREATLY AFFECT VSBY. WITH POTENTIAL FOR BLOWING SLIM WILL GO WITH
HIGH WIND WARNING.
CENTRAL/SOUTHERN VALLEY INTO ADJACENT PORTIONS OF MN...-RA LAST
WEEKEND AND WARM TEMPERATURES ALSO PUT A HEAVY CRUST ON AVAILABLE
THIN SNOW COVER. WITH LITTLE IN ADDITIONAL SNOW FALL ON TOP OF CRUST
THINK BLSN WILL BE MINIMAL CONFINED TO SOME MINOR RESTRICTION IN
OPEN COUNTRY. SHSN AGAIN ALONG FRONT TO BE ISOLD AND NOT A GREAT
IMPACT ON VSBY. MIXED LAYER ALSO NOT AS DEEP AS WEST OF VALLEY AND
BOTH NAM/GFS MODEL SOUNDING INDICATING ABOUT 30KTS TO MIX WHICH
AGAIN SHOULD BE PRETTY EFFICIENT WITH STRENGTH OF COLD ADVECTION.
WIND DIRECTION MORE NW VS N WHICH WOULD LIMIT FAVORABLE FUNNELING
DOWN VALLEY. FOR THIS DO NOT FEEL WE WILL REACH HIGH WIND CRITERIA.
WITH SOME BLOWING AND EVENTUAL WIND CHILLS WITH FALLING TEMPERATURES
WILL OPT FOR WINTER WX ADVISORY VS JUST WIND ADVISORY TO HEIGHTEN
AWARENESS VS WIND ADVISORY.
FAR SOUTHERN FA HAS BEEN THE WARMEST AND DO BELIEVE THERE WILL
MINIMAL BLOWING SNOW. WITH DELAY IN COLDEST AIR TILL THIS AFTERNOON
WILL JUST GO WITH WIND ADVISORY.
VERY COLD AIRMASS WILL HOLD OVER FA FOR THE REMAINDER OF THE PERIOD.
WILL SE AN EXTENDED PERIOD OF EITHER WIND CHILL ADVISORY/WARNING
HEADLINES REMAINDER OF WEEKEND INTO AT LEAST EARLY NEXT WEEK AS
TEMPERATURES LIKELY TO CLIMB ABOVE ZERO AT ANY TIME.
LONG TERM (TUESDAY-FRIDAY)...
NORTHWEST FLOW ALOFT WILL KEEP TEMPS BELOW NORMAL THROUGH THIS
PERIOD. A BIT OF MODERATION IS POSSIBLE FOR MID-WEEK AS THE UPPER
AIR PATTERN DE-AMPLIFIES WITH WEAKENING OF THE WESTERN NORTH AMERICA
RIDGE. HOWEVER...RECENT MODEL RUNS HAVE TRENDED A BIT COLDER FOR
MID-WEEK WITH MUCH OF THE WARMER AIR REMAINING FARTHER SOUTHWEST.
THE GLOBAL MODELS ALL SUGGEST A PACIFIC SHORTWAVE TROUGH WILL LIFT
ACROSS THE NORTHERN ROCKIES INTO THE NORTHERN PLAINS SOMETIME IN THE
LATE WEDNESDAY THROUGH THURSDAY NIGHT TIME FRAME...WITH THE
GEM/ECMWF QUICKER THAN THE GFS. THIS SYSTEM WILL BRING ANOTHER
CHANCE FOR A BIT OF SNOW TO THE AREA...BUT CONFIDENCE IN THE TIMING
AND PLACEMENT IS LOW...GIVEN THE UNCERTAINTY IN THE EVOLUTION OF THE
UPPER SYSTEM AND ASSOCIATED SFC LOW. BEHIND THE SYSTEM...COLDER
TEMPS ARE EXPECTED ONCE AGAIN AS THE NORTHWEST FLOW AMPLIFIES.
AVIATION...
MVFR/IFR CIGS CONFINED TO FAR NORTHERN AREAS IN AREA OF -SN.
REMAINDER OF FA VFR. EXPECT CIGS TO LOWER THIS AFTERNOON IN WAKE OF
STRONG COLD FRONT. LOWEST VSBY EXPECTED ACROSS DVL BASIN INTO
NORTHERN VALLEY WITH GROUND BLIZZARD CONDITIONS. WINDS WILL INCREASE
SIGNIFICANTLY DURING THE MORNING FROM NW-SE. EXPECT WINDS OF
25-40MPH WITH HIGHER GUSTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ030-
039.
WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ052-053.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ006>008-
014>016-024-026-027-054.
HIGH WIND WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ028-029-038-
049.
MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ002-
003-005-008-013>015-022-027-028.
WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ029>032-040.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ001-004-007.
&&
$$
ROGERS/VOELKER/WJB
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
934 PM CST SUN JAN 20 2013
.UPDATE...
WITH EACH SUBSEQUENT MODEL RUN...THE PROSPECTS FOR PATCHY FREEZING
FOG APPEAR TO BE A BIT LOWER...ESPECIALLY IN THE WESTERN HALF OF THE
PANHANDLES. CONSENSUS FCST SOUNDINGS AND MOS FAVOR EITHER LOW CLOUDS
OR NOTHING AT ALL FROM ROUGHLY AMARILLO TO GUYMON WESTWARD. EAST OF
THIS LINE...FREEZING FOG...THOUGH STILL VERY QUESTIONABLE...LOOKS A
BIT MORE LIKELY GIVEN CURRENT DEWPTS NEAR 30F AND EXPECTED LOWS IN
THE HIGH TEENS TO MID 20S. HOWEVER...SLIGHTLY STRONGER GRADIENT WINDS
AND THE POTENTIAL FOR LOW STRATUS TO MOVE IN FIRST COULD PRECLUDE
FREEZING FOG HERE AS WELL.
ALL IN ALL...WILL LEAVE THE INHERITED PATCHY FREEZING FOG MENTION IN
EVERYWHERE FOR LATE TONIGHT AND TOMORROW MORNING...AS IT IS JUST TOO
HARD TO IGNORE THE CURRENT ELEVATED DEWPTS AND CLIMATOLOGICALLY
FAVORABLE SETUP. THINK THE BEST CHANCE FOR FREEZING FOG WILL BE IN
THE PERRYTON/MIAMI/CANADIAN/BEAVER/LIPSCOMB AREAS...THOUGH PATCHY
FREEZING FOG CANNOT BE RULED OUT FOR EVERYONE.
SIMPSON
&&
.PREV DISCUSSION... /ISSUED 535 PM CST SUN JAN 20 2013/
AVIATION...
FOR THE 00Z TAFS...VFR CONDITIONS SHOULD CONTINUE THROUGH 06Z. AFTER
06Z...FORECAST CONFIDENCE DECREASES. THERE WILL BE SOME MOISTURE
POOLING BEHIND THE COLD FRONT WHICH MOVED THROUGH EARLIER. DEPENDING
ON HOW MUCH...THIS COULD LEAD TO THE DEVELOPMENT OF LOW CLOUDS AND
FZFG BETWEEN 06 AND 15Z. HOWEVER...LATEST MODELS HAVE TRENDED DOWN
WITH THE AMOUNT OF MOISTURE AVAILABLE...SO HAVE ONLY MENTIONED A SCT
DECK AND MVFR VISIBILITIES FOR NOW.
JOHNSON
PREV DISCUSSION... /ISSUED 310 PM CST SUN JAN 20 2013/
DISCUSSION...
THROUGH TONIGHT: MAIN CONCERN TONIGHT REVOLVES AROUND POTENTIAL
DEVELOPMENT OF FREEZING FOG VS. LOW STRATUS. A DRY COLD FRONT
LOCATED ALONG THE CANADIAN RIVER VALLEY IS TRUCKING SOUTHWARD THIS
AFTERNOON. STRONG NORTHERLY WINDS HAVE DEVELOPED BEHIND THE FRONT
WITH A FEW GUSTS UP TO 35 MPH. THIS NORTHERLY SURGE OF GUSTY WINDS
WILL CONTINUE TO PUSH SOUTHWARD THROUGH THE AFTERNOON AND EVENING
HOURS, BUT IT SHOULD DIMINISH IN INTENSITY NEAR SUNSET. LOW-LEVEL
MOISTURE IS EXPECTED TO POOL BEHIND THE FRONT TONIGHT, BUT MODEL
GUIDANCE SHOWS VARYING DEGREES OF MOISTURE CONTENT. THE LATEST RUC
AND HRRR HAVE BACKED OFF ON THE POTENTIAL FOR WIDESPREAD FREEZING
FOG, BUT THE GFS AND NAM CONTINUE TO INDICATE THIS POTENTIAL. GIVEN
THE SYNOPTIC PATTERN, THIS SETUP IS LOCALLY FAVORABLE FOR SOME
PATCHY (FREEZING) FOG, SO WE LEFT THIS IN THE FORECAST. WE EXPECT
FREEZING FOG TO DEVELOP BETWEEN 3 AM ACROSS THE EASTERN PANHANDLES
AND SPREAD WESTWARD. OTHER MODEL GUIDANCE, INCLUDING THE TEXAS TECH
WRF, INDICATES THAT LOW STRATUS WILL BE MORE FAVORED THAN FOG. DUE
TO THESE UNCERTAINTIES, WE INCLUDED BOTH INCREASING CLOUDS AND PATCHY
FREEZING FOG IN THE FORECAST, BUT OUR FORECAST CONFIDENCE IS LOW.
OVERNIGHT LOW TEMPERATURES WILL RANGE FROM THE UPPER TEENS TO UPPER
20S. THE POTENTIAL FOR FREEZING DRIZZLE THAT WE DISCUSSED YESTERDAY
HAS DIMINISHED AS THE DEPTH OF THE MOIST LAYER WILL BE LESS THAN
2000 FEET.
MARTIN LUTHER KING, JR. DAY-NIGHT: ANY FREEZING FOG THAT DEVELOPS
OVERNIGHT SHOULD DISSIPATE BY 10 AM. LOW CLOUDS, IF THEY DEVELOP,
COULD HANG TOUGH INTO THE EARLY AFTERNOON HOURS, ESPECIALLY ACROSS
THE SOUTHEASTERN TEXAS PANHANDLE. SURFACE WINDS WILL QUICKLY SHIFT TO
THE SOUTH BY THE AFTERNOON HOURS, BUT HIGH TEMPERATURES WILL BE ABOUT
10-15 DEGREES COLDER THAN TODAY DUE TO THE MODIFIED ARCTIC AIR MASS.
TUESDAY-SUNDAY: A BACKDOOR COLD FRONT WILL SNEAK INTO THE
NORTHEASTERN HALF OF THE FORECAST AREA TUESDAY MORNING AND MAY BE
SLOW TO RETREAT NORTHWARD. THIS SHOULD KEEP AN UPSLOPE COMPONENT TO
THE WINDS FOR MUCH OF THE DAY. AS A RESULT, WE COOLED HIGHS OFF
SEVERAL DEGREES, AND THERE IS A POSSIBILITY WE MAY STILL BE TOO WARM.
THIS FRONT WILL LIFT OUT OF THE FORECAST AREA ON WEDNESDAY AS UPPER
RIDGING BUILDS ACROSS THE AREA. HIGHS ON WEDNESDAY ARE EXPECTED TO
WARM INTO THE LOWER 60S TO POSSIBLY NEAR 70. AN UPPER TROUGH MOVING
INTO NORTHERN PLAINS ON THURSDAY WILL SWING ANOTHER DRY COLD FRONT
SOUTHWARD. WE SPED UP THE TIMING OF THE FRONT GIVEN THAT IT WILL ALSO
BE A STRONG FRONT. AS A RESULT, HIGHS FOR THURSDAY HAVE BEEN TRIMMED
DOWNWARD AND WIND SPEEDS INCREASED, ESPECIALLY BEHIND THE FRONT.
COOLER TEMPERATURES WILL RETURN FOR FRIDAY, BUT A WARMING TREND WILL
RESUME FOR NEXT WEEKEND.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
MONDAY THROUGH WEDNESDAY AS RELATIVE HUMIDITY VALUES WILL REMAIN
ABOVE 20 PERCENT AND/OR 20-FOOT WINDS WILL REMAIN BELOW 15 MPH.
ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS THE WESTERN
TWO THIRDS OF THE PANHANDLES ON THURSDAY AS DRY NORTHERLY WINDS
INCREASE. ELEVATED FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE
ACROSS THE FAR WESTERN PANHANDLES ON SATURDAY.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
16/09
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
535 PM CST SUN JAN 20 2013
.AVIATION...
FOR THE 00Z TAFS...VFR CONDITIONS SHOULD CONTINUE THROUGH 06Z. AFTER
06Z...FORECAST CONFIDENCE DECREASES. THERE WILL BE SOME MOISTURE
POOLING BEHIND THE COLD FRONT WHICH MOVED THROUGH EARLIER. DEPENDING
ON HOW MUCH...THIS COULD LEAD TO THE DEVELOPMENT OF LOW CLOUDS AND
FZFG BETWEEN 06 AND 15Z. HOWEVER...LATEST MODELS HAVE TRENDED DOWN
WITH THE AMOUNT OF MOISTURE AVAILABLE...SO HAVE ONLY MENTIONED A SCT
DECK AND MVFR VISIBILITIES FOR NOW.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 310 PM CST SUN JAN 20 2013/
DISCUSSION...
THROUGH TONIGHT: MAIN CONCERN TONIGHT REVOLVES AROUND POTENTIAL
DEVELOPMENT OF FREEZING FOG VS. LOW STRATUS. A DRY COLD FRONT
LOCATED ALONG THE CANADIAN RIVER VALLEY IS TRUCKING SOUTHWARD THIS
AFTERNOON. STRONG NORTHERLY WINDS HAVE DEVELOPED BEHIND THE FRONT
WITH A FEW GUSTS UP TO 35 MPH. THIS NORTHERLY SURGE OF GUSTY WINDS
WILL CONTINUE TO PUSH SOUTHWARD THROUGH THE AFTERNOON AND EVENING
HOURS, BUT IT SHOULD DIMINISH IN INTENSITY NEAR SUNSET. LOW-LEVEL
MOISTURE IS EXPECTED TO POOL BEHIND THE FRONT TONIGHT, BUT MODEL
GUIDANCE SHOWS VARYING DEGREES OF MOISTURE CONTENT. THE LATEST RUC
AND HRRR HAVE BACKED OFF ON THE POTENTIAL FOR WIDESPREAD FREEZING
FOG, BUT THE GFS AND NAM CONTINUE TO INDICATE THIS POTENTIAL. GIVEN
THE SYNOPTIC PATTERN, THIS SETUP IS LOCALLY FAVORABLE FOR SOME
PATCHY (FREEZING) FOG, SO WE LEFT THIS IN THE FORECAST. WE EXPECT
FREEZING FOG TO DEVELOP BETWEEN 3 AM ACROSS THE EASTERN PANHANDLES
AND SPREAD WESTWARD. OTHER MODEL GUIDANCE, INCLUDING THE TEXAS TECH
WRF, INDICATES THAT LOW STRATUS WILL BE MORE FAVORED THAN FOG. DUE
TO THESE UNCERTAINTIES, WE INCLUDED BOTH INCREASING CLOUDS AND PATCHY
FREEZING FOG IN THE FORECAST, BUT OUR FORECAST CONFIDENCE IS LOW.
OVERNIGHT LOW TEMPERATURES WILL RANGE FROM THE UPPER TEENS TO UPPER
20S. THE POTENTIAL FOR FREEZING DRIZZLE THAT WE DISCUSSED YESTERDAY
HAS DIMINISHED AS THE DEPTH OF THE MOIST LAYER WILL BE LESS THAN
2000 FEET.
MARTIN LUTHER KING, JR. DAY-NIGHT: ANY FREEZING FOG THAT DEVELOPS
OVERNIGHT SHOULD DISSIPATE BY 10 AM. LOW CLOUDS, IF THEY DEVELOP,
COULD HANG TOUGH INTO THE EARLY AFTERNOON HOURS, ESPECIALLY ACROSS
THE SOUTHEASTERN TEXAS PANHANDLE. SURFACE WINDS WILL QUICKLY SHIFT TO
THE SOUTH BY THE AFTERNOON HOURS, BUT HIGH TEMPERATURES WILL BE ABOUT
10-15 DEGREES COLDER THAN TODAY DUE TO THE MODIFIED ARCTIC AIR MASS.
TUESDAY-SUNDAY: A BACKDOOR COLD FRONT WILL SNEAK INTO THE
NORTHEASTERN HALF OF THE FORECAST AREA TUESDAY MORNING AND MAY BE
SLOW TO RETREAT NORTHWARD. THIS SHOULD KEEP AN UPSLOPE COMPONENT TO
THE WINDS FOR MUCH OF THE DAY. AS A RESULT, WE COOLED HIGHS OFF
SEVERAL DEGREES, AND THERE IS A POSSIBILITY WE MAY STILL BE TOO WARM.
THIS FRONT WILL LIFT OUT OF THE FORECAST AREA ON WEDNESDAY AS UPPER
RIDGING BUILDS ACROSS THE AREA. HIGHS ON WEDNESDAY ARE EXPECTED TO
WARM INTO THE LOWER 60S TO POSSIBLY NEAR 70. AN UPPER TROUGH MOVING
INTO NORTHERN PLAINS ON THURSDAY WILL SWING ANOTHER DRY COLD FRONT
SOUTHWARD. WE SPED UP THE TIMING OF THE FRONT GIVEN THAT IT WILL ALSO
BE A STRONG FRONT. AS A RESULT, HIGHS FOR THURSDAY HAVE BEEN TRIMMED
DOWNWARD AND WIND SPEEDS INCREASED, ESPECIALLY BEHIND THE FRONT.
COOLER TEMPERATURES WILL RETURN FOR FRIDAY, BUT A WARMING TREND WILL
RESUME FOR NEXT WEEKEND.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
MONDAY THROUGH WEDNESDAY AS RELATIVE HUMIDITY VALUES WILL REMAIN
ABOVE 20 PERCENT AND/OR 20-FOOT WINDS WILL REMAIN BELOW 15 MPH.
ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS THE WESTERN
TWO THIRDS OF THE PANHANDLES ON THURSDAY AS DRY NORTHERLY WINDS
INCREASE. ELEVATED FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE
ACROSS THE FAR WESTERN PANHANDLES ON SATURDAY.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
16/09
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
526 PM CST SUN JAN 20 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
250 PM CST SUN JAN 20 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES/WIND CHILLS THROUGH
TUESDAY AND ANY POTENTIAL LIGHT PRECIPITATION THROUGHOUT THE SHORT
TERM.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE U.S. WEST COAST INTO WESTERN BRITISH
COLUMBIA...WHILE DEEP TROUGHING ENCOMPASSED THE EASTERN TWO-THIRDS
OF CANADA INTO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES
REGIONS. 500MB HEIGHTS AS WELL AS 850MB TEMPS WERE 1-1.5 STANDARD
DEVIATIONS BELOW NORMAL OVER THE FORECAST AREA. REGARDING THE 850MB
TEMPS...RAP ANALYSIS SHOWED READINGS OF -16 TO -20C OVER THE
FORECAST AREA. WITHIN THE DEEP TROUGHING...A SHORTWAVE WAS EVIDENT
FROM EASTERN SOUTH DAKOTA INTO NORTHERN IOWA. DPVA ASSOCIATED WITH
THE SHORTWAVE...MID-LEVEL MOISTURE SEEN ON THE 12Z ABR SOUNDING...AS
WELL AS LOW TO MID LEVEL FRONTOGENESIS WAS SUPPORTING AN AREA OF
LIGHT SNOW JUST SOUTH OF THE SHORTWAVE ACROSS WESTERN AND CENTRAL
IOWA. ONLY SOME SCATTERED ALTOSTRATUS HAS OVERSPREAD THE FORECAST
AREA ASSOCIATED WITH THE SHORTWAVE. SUNSHINE THROUGH THESE CLOUDS
AND THE COLD 850MB TEMPS HAS ONLY ALLOWED TEMPERATURES TO CLIMB INTO
THE LOWER TO MID TEENS. ON THE WEST SIDE OF THE DEEP TROUGH...A
120-140 KT JET AT THE TROPOPAUSE WAS DROPPING DOWN THROUGH EASTERN
ALBERTA AND SASKATCHEWAN. THE STRENGTH OF THIS JET IS PARTLY DUE TO
ANOTHER SURGE OF ARCTIC AIR...WITH THE RAP SHOWING 850MB TEMPS OF
-25 TO -30C FROM NORTH DAKOTA INTO MANITOBA. THIS COLD AIR WAS ALSO
SITTING RIGHT BEHIND A COLD FRONT STRETCHING FROM NEAR ABERDEEN
SOUTH DAKOTA INTO THE MN ARROWHEAD.
TONIGHT AND MONDAY...THE 120-140 KT JET STREAK OVER EASTERN ALBERTA
INTO SASKATCHEWAN IS PROGGED TO DIG INTO THE DAKOTAS TONIGHT AND INTO
IOWA ON MONDAY. THE FORECAST AREA ENDS UP IN THE LEFT EXIT REGION OF
THIS JET MONDAY MORNING...WHILE THE TROPOPAUSE DROPS TO AROUND
375MB. THESE STRENGTHENING UPPER DYNAMICS WILL END UP TIGHTENING THE
SURFACE PRESSURE GRADIENT OVER THE FORECAST AREA TONIGHT...HELPING
TO BRING IN THAT VERY COLD 850MB AIR ACROSS NORTH DAKOTA. NOT
ANTICIPATING ANY PRECIPITATION FROM THE DYNAMICAL FORCING...
PRIMARILY BECAUSE THERE IS TOO MUCH MID-LEVEL DRY AIR ACCOMPANYING
THE COLD ADVECTION AS SHOWN ON FORECAST SOUNDINGS. IN ADDITION...
THERE ARE CLEAR SKIES CURRENTLY PRESENT OVER NORTHWEST NORTH DAKOTA
AND SOUTH CENTRAL CANADA IN THE LEFT EXIT REGION. ONLY PRECIPITATION
THAT MAY OCCUR WOULD BE LIMITED TO FLURRIES...ASSOCIATED WITH THE
LOW CLOUDS AHEAD OF THAT COLD FRONT DROPPING SOUTHEAST OUT OF
NORTHERN SOUTH DAKOTA INTO THE MN ARROWHEAD. ADDITIONAL FLURRIES
COULD OCCUR ON MONDAY NORTH OF I-94...ASSOCIATED WITH LOW TO MID
LEVEL MOISTURE MOVING THROUGH WHICH IS CURRENTLY IN NORTHERN
MANITOBA. REGARDING TEMPERATURES...THEY ARE TRICKY GIVEN THE LACK OF
SNOW COVER AND THE INCREASING WINDS PROMOTING MIXING. WE DEFINITELY
ARE NOT GOING TO GET AS COLD AS THE DAKOTAS AND NORTHERN MN WHERE
SNOW EXISTS. STILL...ADVECTION ALONE AND CLEARING SKIES...COMBINED
WITH THE FACT THAT THE INCOMING 850MB TEMPS ARE 2-2.5 STANDARD
DEVIATIONS BELOW NORMAL...SHOULD ALLOW TEMPERATURES IN MOST
LOCATIONS TO DROP BELOW ZERO. SOME LOCATIONS OVER NORTH CENTRAL
WISCONSIN AND SOUTHEAST MN COULD EVEN DROP TO 10 BELOW ZERO OR SO.
TEMPERATURES WILL STRUGGLE TO RECOVER ON MONDAY BEING UNDER THE
850MB THERMAL TROUGH...BUT SUN AND BARE GROUND SHOULD GET HIGHS TO
NEAR OR SLIGHTLY ABOVE ZERO PER THE ECMWF. THE ECMWF HAS DONE WELL
HANDLING HIGH TEMPERATURES WITH THE BARE GROUND AND THUS WAS THE
PREFERRED GUIDANCE. WIND CHILLS WILL SOLIDLY END UP IN THE WIND
CHILL ADVISORY RANGE FROM LATE TONIGHT INTO MUCH OF MONDAY... AND
MAY EVEN APPROACH WARNING MONDAY MORNING OVER PORTIONS OF SOUTHEAST
MN. CONFIDENCE IS STILL NOT HIGH ENOUGH TO GO WITH THE WARNING GIVEN
UNCERTAINTY ON LOW TEMPERATURES.
MONDAY NIGHT AND TUESDAY...THE DEEP UPPER TROUGH IS PROGGED TO SHIFT
SLIGHTLY EASTWARD DURING THIS PERIOD AS THE RIDGE ALONG THE U.S.
WEST COAST GETS A PUSH EAST. IN RESPONSE...THE ARCTIC HIGH PRESSURE
AREA CURRENTLY SITTING UP IN ALBERTA IS ALLOWED TO BUILD INTO THE
FORECAST AREA. MODELS ARE IN GOOD AGREEMENT OF THE HIGH PRESSURE
AREA ENCOMPASSING THE AREA AT 00Z WEDNESDAY. UNTIL THE HIGH BUILDS
IN...A SLOWLY WEAKENING PRESSURE GRADIENT WILL EXIST...MAINTAINING A
NORTHWESTERLY BREEZE AND KEEPING WIND CHILLS DOWN. THUS...HAVING THE
WIND CHILL ADVISORY GO TO 18Z TUESDAY STILL LOOKS GOOD. SKIES SHOULD
END UP CLEAR IN MOST AREAS BY 12Z TUESDAY...FAVORING GOOD
RADIATIONAL COOLING. AGAIN...THE LACK OF SNOW COVER AND BREEZE WILL
ACT AGAINST GETTING TOO COLD. GIVEN THE COLDER MONDAY COMPARED TO
TODAY...SHOULD SEE LOWS AT LEAST A FEW DEGREES COLDER...ESPECIALLY
OVER THE SNOWPACK NORTH OF HIGHWAY 10. 850MB AND 925MB TEMPERATURES
ARE PROGGED TO ONLY SLOWLY RECOVER...CLIMBING TO -18 TO -22C AND -16
TO -22C RESPECTIVELY BY 00Z. DESPITE PLENTY OF SUNSHINE MINUS SOME
INCREASING HIGH CLOUDS IN THE AFTERNOON...ONLY ANTICIPATING HIGHS 5
TO 10 DEGREES WARMER PER ECMWF.
TUESDAY NIGHT AND WEDNESDAY...MODELS PROG A POTENT SHORTWAVE TO DROP
SOUTH OUT OF NORTHERN MANITOBA LATE TUESDAY AND HAVE IT CROSS LAKE
SUPERIOR LATE WEDNESDAY. MEANWHILE...THE WESTERN UPPER RIDGE BREAKS
DOWN AND FLATTENS WHILE SPREADING EAST...IN RESPONSE TO A POTENT
SHORTWAVE TROUGH CROSSING THE PACIFIC NORTHWEST. THE RESULT OF ALL
THIS IS TO STRENGTHEN THE UPPER JET CORE AT THE TROPOPAUSE OVER OR
JUST NORTH OF THE FORECAST AREA...TOWARDS 150-170 KT. WITH THE
STRENGTHENING UPPER JET COMES AN ISENTROPIC LIFT AND LOW TO MID
LEVEL FRONTOGENESIS ZONE ON ITS SOUTHWEST SIDE. THIS RESULTS IN
INCREASING AND THICKENING MID AND HIGH CLOUDS OVER THE FORECAST
AREA. FORCING IS NOT ALL THAT STRONG PER MODEL DERIVED OMEGA
FIELDS...BUT THE LOW LEVELS DO SLOWLY SATURATE OVER TIME. THUS...
THINK FLURRIES AT A MINIMUM WILL OCCUR. 20.12Z NAM ACTUALLY PRODUCES
SOME LIGHT QPF...ALBEIT IS THE MOST DYNAMIC BY EVEN HAVING A SURFACE
LOW DROPPING THROUGH IOWA. FOR NOW JUST WENT WITH ADDING
FLURRIES...BUT SOME CHANCES OF PRECIPITATION MAY NEED TO BE ADDED IF
MODELS TREND TOWARDS THE NAM. WITH THE THICKENING CLOUD COVER
AND BARE GROUND...TEMPERATURES SHOULD NOT FALL ALL THAT MUCH TUESDAY
NIGHT. 925MB TEMPS WARM FURTHER ON WEDNESDAY WITH THE UPPER FLOW
TURNING MORE WEST-NORTHWESTERLY...CLIMBING TO -8C SOUTHWEST TO -16C
NORTHEAST BY 00Z. THUS...DESPITE CLOUD COVER...TEMPERATURES SHOULD
BE ABLE TO CLIMB INTO THE MID TEENS TO MID 20S.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
250 PM CST SUN JAN 20 2013
VERY GOOD AGREEMENT EXISTS ON THE LONG TERM PATTERN FROM THE 20.12Z
ECMWF/GFS/CANADIAN AND ECMWF ENSEMBLES. THE SHORTWAVE TROUGH OVER
THE PACIFIC NORTHWEST TO START THE PERIOD DIGS INTO NEBRASKA AND
IOWA FOR THURSDAY. AN INVERTED TROUGH ACCOMPANIES THE SHORTWAVE...
WITH A COMBINATION OF MID-LEVEL FRONTOGENESIS...DPVA AND MOISTURE
EXPECTING TO BRING SOME SNOW ACROSS THE FORECAST AREA. HOWEVER...
THIS HAS BEEN A POINT OF CONTENTION FOR A FEW DAYS...WITH MODELS
VARYING ON HOW MUCH QPF WITH EVEN A FEW SUGGESTING DRY EITHER ON
THURSDAY AND/OR THURSDAY NIGHT. AS SUCH...HAVE KEPT A CONSENSUS
AROUND 30 PERCENT CHANCE FOR BOTH THURSDAY AND THURSDAY NIGHT.
CERTAINLY IF THE TREND IN THE 20.12Z ECMWF CONTINUES...WE WILL NEED
HIGHER CHANCES AS IT NOW SUGGESTS UPWARDS OF 2-3 INCHES OF SNOW.
THIS IS QUITE A BIT DIFFERENT FROM ITS PREVIOUS RUN...THOUGH.
ANOTHER SURGE OF CANADIAN AIR WITH HIGH PRESSURE IS STILL FORECAST
TO DROP INTO THE FORECAST AREA IN THE WAKE OF THIS SYSTEM FOR FRIDAY
AND FRIDAY NIGHT. HOWEVER...THE 850MB TEMPS ARE NOT NEARLY AS COLD
AS THE CURRENT ARCTIC AIR SURGE...ONLY PROGGED TO DIP DOWN TO -20C
AT MOST.
FOR THE WEEKEND...A DEEP TROUGH IS FORECAST TO FORM JUST OFF OR ON
THE WEST COAST OF THE U.S....SETTING UP A PATTERN CHANGE AS 500MB
HEIGHTS RISE DOWNSTREAM ACROSS THE REST OF THE U.S.. EVENTUALLY A
LOW PRESSURE SYSTEM FORMS IN THE VICINITY OF WYOMING AND COLORADO BY
LATE SUNDAY...BUT MOISTURE RETURN TOWARDS THE FORECAST AREA IS STILL
LIMITED. THUS...A DRY WEEKEND WITH WARMING TEMPERATURES IS IN STORE.
HOW WARM WILL DEPEND ON HOW MUCH SNOW OCCURS WITH THE THURSDAY
SYSTEM. FOLLOWED THE CONSENSUS FOR HIGH TEMPERATURES FOR THE
WEEKEND...BUT THESE MAY STILL BE TOO COOL GIVEN 925MB TEMPS
CLIMBING TO 0 TO -4C BY 18Z SUNDAY PER 20.12Z GFS/ECMWF.
&&
.AVIATION...TONIGHT AND MONDAY
526 PM CST SUN JAN 20 2013
AS ARCTIC HIGH PRESSURE BUILDS SOUTHWARD THROUGH THE PLAINS
TONIGHT...THE PRESSURE GRADIENT DOES TIGHTEN ACROSS THE AREA
BETWEEN THE HIGH AND AN AREA OF LOW PRESSURE OVER THE EASTERN
GREAT LAKES. THUS EXPECT WINDS TO INCREASE AT THE TAF SITES AROUND
06Z WITH SOME GUSTS TOP 20 TO 25 KNOTS. AS THE GRADIENT RELAXES
SOMEWHAT AFTER 18Z MONDAY...THE WINDS WILL DIMINISH SOMEWHAT BUT
WILL REMAIN ABOVE 12 KNOTS. AS FOR CEILINGS...EXPECT A BAND OF VFR
STRATUS 035K-045K TO PUSH ACROSS THE SITES THIS EVENING BETWEEN
00Z-06Z. OTHERWISE VFR HIGH CLOUDS EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST SUN JAN 20 2013
WI...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR WIZ017-029-032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR MNZ079-086>088-094>096.
IA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
512 PM CST SUN JAN 20 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE BUILDING SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS
BENEATH NORTHWEST FLOW ALOFT. EMBEDDED SHORTWAVE TROUGH WITHIN THIS
NW FLOW IS MOVING OVER WESTERN LAKE SUPERIOR EARLY THIS AFTERNOON AND
IS HELPING TO PRODUCE SNOW SHOWERS AND FLURRIES OVER NORTHERN
MINNESOTA WHICH ARE PUSHING INTO NORTHWEST WISCONSIN. THE NEXT PUSH
OF BITTERLY COLD ARCTIC AIR EXISTS BEHIND THIS SHORTWAVE WHERE
TEMPERATURES REMAIN BELOW 0F. FORECAST CONCERNS INCLUDE SMALL
PRECIP CHANCES THIS EVENING...THEN TEMPERATURES AND ASSOCIATED
HEADLINES.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE ACROSS THE UPPER PENINSULA
OVER THE REST OF THE AFTERNOON AND EARLY THIS EVENING. TAIL OF THE
VORT MAX WILL PUSH AN AREA OF CLOUDS AND FLURRIES ACROSS THE AREA
LATE THIS AFTERNOON AND THIS EVENING. HAVE ADDED THE CHANCE OF
FLURRIES TO THE FORECAST. LOW LEVEL WINDS LOOK TOO WESTERLY FOR
LAKE EFFECT SNOW TO BE MUCH OF AN ISSUE FOR VILAS COUNTY. BUT WITH
ENHANCEMENT FROM THE SHORTWAVE THIS EVENING...WILL KEEP A CHANCE OF
SNOW SHOWERS OVER VILAS AND ACCUMS LESS THAN A HALF INCH. TIMING
THE DEPARTURE OF THE CLOUDS IS DIFFICULT SINCE RH IN THE 900-800MB
LAYER REMAINS FAIRLY HIGH. SATELLITE IMAGERY SHOWS CLEARING TAKING
PLACE OVER NORTHERN MINNESOTA AND ONTARIO...SO THINK SKIES WILL AT
LEAST PARTIALLY CLEAR FROM WEST TO EAST AFTER MIDNIGHT TONIGHT.
TEMPERATURES WERE FIRMLY IN THE TEENS BELOW ZERO OVER NORTHERN
MINNESOTA THIS MORNING. WILL HAVE COMPARATIVELY MORE WIND THAN
FARTHER WEST...BUT STILL THINK WILL REACH IN THE LOW TEENS BELOW
ZERO OVER NORTH-CENTRAL WISCONSIN. WITH NW WINDS 7-12 KTS
TONIGHT...WIND CHILL READINGS WILL APPROACH 20 BELOW OVER
NORTH-CENTRAL WISCONSIN AROUND 06Z...AND OVER THE FOX VALLEY BY
10Z. WILL BEGIN THE NEW WIND CHILL HEADLINES AT THOSE TIMES.
MONDAY...NORTHWEST WINDS WILL CONTINUE TO POUR BITTERLY COLD ARCTIC
AIR ACROSS THE REGION...DROPPING 850MB TEMPS TO 28-29C BELOW ZERO.
ANOTHER WEAK SHORTWAVE WILL BE SWINGING ACROSS THE STATE. SOME
FLURRIES OR LIGHT SNOW NORTH OF LAKE WINNIPEG WITH THIS FEATURE AND
WILL ADD TO THE FORECAST OVER NORTH-CENTRAL AND CENTRAL WISCONSIN.
NW WINDS WILL REMAIN BREEZY...AND TEMPS WILL STRUGGLE TO REACH ABOVE
0F. WIND CHILL READINGS MAY BRIEFLY RISE ABOVE ADVISORY CRITERIA
FOR A FEW HOURS DURING THE AFTERNOON OVER THE FOX VALLEY AND
ADJACENT TO GREEN BAY. BUT HEADLINES WILL HAVE TO BE ISSUED AGAIN
BY 23-24Z...SO WILL JUST RUN HEADLINES THROUGH MONDAY NIGHT. HIGHS
RANGING FROM 6 BELOW OVER N-C WISCONSIN...TO ABOUT 6 ABOVE NEAR LAKE
MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. COLD ARCTIC AIR
INTRUSION WILL CONTINUE TO GRAB THE HEADLINES FOR THE FIRST HALF
OF THE WEEK. AN ONGOING WIND CHILL ADVISORY EXPECTED OVER WESTERN
AREAS TROUGH TUESDAY NOON. THE REST OF THE FORECAST AREA INCLUDING
THE LAKESHORE REGION WILL BE ADDED STARTING MONDAY EVENING AND
LASTING THROUGH NOON AS WELL AS THE CORE OF THE COLDEST AIR
FILTERS OVER THE AREA. MATTER OF FACT...LATER SHIFTS MAY POSSIBLY
NEED TO UPGRADE TO A WIND CHILL WARNING OVER PORTIONS OF NORTHERN
AND PARTS OF CENTRAL WISCONSIN MONDAY NIGHT. RESURGENT COLD AIR
AND NORTHWEST WINDS WILL CONTINUE LAKE EFFECT SNOW SHOWERS FAR
NORTH BUT DRY AIR MASS AND LOW INVERSIONS WILL LIKELY LIMIT PLUME
DEVELOPMENT.
WINDS WILL BE ON THE DECREASE LATER TUESDAY INTO WEDNESDAY AS A
COLD HIGH PRESSURE SYSTEM SETTLES OVER THE AREA. LAKE EFFECT SNOW
SHOWERS END AS WINDS TURN MORE SOUTHWEST...BUT ANOTHER COLD NIGHT
EXPECTED WITH THE LIGHTER WINDS UNDER THE HIGH PRESSURE SYSTEM.
MIN TEMPERATURES WILL BE IMPACTED BY CLOUDS THROUGH WEDNESDAY...BUT
GUIDANCE TENDS TO OVERDUE THE CLOUDS AT TIMES DUE TO THE RELATIVE
EASE TO SATURATE A COLD DRY AIR MASS. WITH SUCH A COLD AIR MASS
DROPPING IN FOR THE FIRST HALF OF THE WEEK...YOU WONDER HOW COLD
IT COULD HAVE BEEN WITH A FRESH DEEP SNOW COVER. WITH THE LIMITED
SNOW COVER...THE ARCTIC AIR WILL DRIVE AREA FROST DEPTHS DEEPER
THIS WEEK.
WEAK WAA STARTS ON WEDNESDAY AS A SHORT WAVE TROUGH DROPS INTO THE
NORTHERN GREAT LAKES REGION. MORE WIDESPREAD CLOUDS IN THE
BAROCLINIC ZONE FROM MT TO THE OHIO VALLEY TODAY MAY EDGE NORTH
INTO PARTS OF CENTRAL WISCONSIN WEDNESDAY AND CONTINUE TO SPREAD
NORTH THROUGH THURSDAY. LIGHT SNOW REMAINS IN THE FORECAST LATER
IN THE WEEK AS A CLIPPER SYSTEM DROPS INTO THE REGION AND PHASES
WITH SOME SOUTHERN STREAM ENERGY SOUTH AND EAST OF THE AREA. LAKE
EFFECT POTENTIAL INCREASES AGAIN THURSDAY NIGHT AND FRIDAY AS CAA
WITH NORTHWEST WINDS DEVELOP IN THE WAKE OF THE CLIPPER SYSTEM.
ANY LAKE EFFECT SNOW WILL END FRIDAY NIGHT AS A MODERATING
TEMPERATURE PATTERN STARTS WITH A RETURN TO A ZONAL FLOW WITH WAA
FOR THE WEEKEND.
&&
.AVIATION...FOR 00Z TAF ISSUANCE. PATCHES OF CLDS AND SOME
FLURRIES WL STREAM SE FM TIME TO TIME UNDER COLD NWLY FLOW ALOFT.
EXPECT PRIMARILY VFR CONDITIONS.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 4 AM MONDAY TO NOON CST TUESDAY FOR
WIZ013-020-021-031-037>039-045-048-049-073-074.
WIND CHILL ADVISORY FROM 6 PM MONDAY TO NOON CST TUESDAY FOR
WIZ022-040-050.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR WIZ005-010>012-018-019-030-035-036.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
443 PM CST SAT JAN 19 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A
SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS
WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH
DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING
THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE
ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING
VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY
INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS
JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING
QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN
THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE
PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT
RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE
STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND
DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO
THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST
AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW
AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO
WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY
THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS
MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL
UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER
NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT
BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST
WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS.
HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW
ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A
RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN
CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE
SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE.
BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT
IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD
ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC
PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD
APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON
AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF
45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL
WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF
HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR
TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT
ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO
OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING
STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY
MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A
RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO
END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING
ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW
ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON
SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW
SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS
SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR
WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH
ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE
SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE
SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE
ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND
CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF
THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE
REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER
AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE
INDICATING A MODERATING TREND LATER NEXT WEEKEND.
ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS
WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS
SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT
VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT.
TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE
COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS
EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR.
LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH
THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME
DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT
TOO WESTERLY WIND DIRECTION.
TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A
CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS
THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY
NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH
HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM.
WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR
TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT
FAR OUT REASONABLE.
&&
.AVIATION...FOR 00Z TAF ISSUANCE. ARCTIC FRONT SURGING SE ACRS THE
AREA. WL SEE A PERIOD OF STG WINDS AND SOME MVFR CIGS AND VSBYS
THIS EVENING. BRIEF IFR CONDITONS POSSIBLE. NOT REALLY THAT MUCH
SNOW TO BLOW ARND IN THE AREA...SO EXPECT CONDITIONS TO IMPROVE
BACK TO VFR BY LATE TNGT. THE EXCEPTION MAY BE IN THE FAR N /RHI/
WHERE CLDS OFF LAKE SUPERIOR WL CONT TO STREAM SE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ038>040-048>050.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-
045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ005-010-011-018-019-030-035-036.
WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
315 PM CST SAT JAN 19 2013
.SHORT TERM...
TONIGHT - CONFIDENCE...MEDIUM
STRENGTHENING LOW PRESSURE CONTINUES TO SHIFT EAST FROM NEAR LAKE
SUPERIOR. NICE POCKET OF PRESSURE DRIVING SOUTHEAST FROM THE
DAKOTAS. THE RUC IS BEHIND SCHEDULE A BIT ON THIS...BUT HAS A A
PRESSURE RISE MAX OVER THE CWA AT 6Z...BUT MAY END UP BEING MORE
AROUND 3Z. LEADING EDGE OF ARCTIC FRONT DRIVING SE FROM CENTRAL MN.
FRONT EXPECTED TO CLEAR THE SOUTHEAST BY 3Z. BUFKIT SOUNDINGS SHOW
FAIRLY DEEP POST-FRONTAL MIXING AND STRONG SUBSIDENCE FROM LATER
THIS EVENING INTO THE OVERNIGHT WITH WIND ADVISORY CRITERIA STILL
LIKELY. IN FACT RAP SOUNDINGS VERY IMPRESSIVE ACTUALLY SHOWING
BORDERLINE WARNING FOR A TIME. RUC PROGGED 3 HOUR PRESSURE RISE OF
4-5 MB SLIDING ACROSS LATER COMBINED WITH 50 KNOT 850 WIND MAX
SUGGESTS THIS IDEA. AT THIS POINT WE ARE LOOKING AT A HIGH END
ADVISORY/LOW END WARNING. WILL RETAIN THE ADVISORY AT THIS POINT BUT
WOULD NOT BE SURPRISED TO SEE A FEW GUSTS EXCEED THE WARNING
THRESHOLD.
GUIDANCE NUMBERS STILL SUPPORT SINGLE DIGIT LOWS FOR MUCH OF CWA.
PREFER THE DRIER LOOK THE NAM/HPC VERSUS GFS/ECMWF WITH RESPECT TO
QPF IN THE COLD ADVECTION REGIME. STRATUS POTENTIAL THERE GIVEN
MODEL AGREEMENT IN LOW LEVEL RH PROGS. WILL NOT MENTION FLURRIES
AT THIS TIME WITH VERY LITTLE REPORTS UPSTREAM THOUGH FLOW WILL BE
CYCLONIC BUT LOW LEVELS TO BECOME DOMINATED BY SUBSIDENCE. GIVEN
THE SLOWER ARRIVAL OF THE FRONT...PUSHED EASTERN WIND ADVISORY
AHEAD AN HOUR. KEPT THE WEST AS IS TO BLEND WITH NEIGHBORS.
SUNDAY - CONFIDENCE...MEDIUM
ARCTIC AIR-MASS IN PLACE. 925 TEMPS AVERAGING -14 TO -17C SUGGEST
TEMPS MODIFYING INTO THE TEENS WHICH SEEMS REASONABLE WITH ABSENCE OF
SNOW-COVER. ELONGATED SHORTWAVE DROPS ACROSS THE AREA. NOT OVERLY
IMPRESSED WITH THIS FEATURE. QPF PROGS TREND THIS FURTHER WEST OR
SOUTHWEST OF THE CWA. FOCUS APPEARS WEST CLOSER TO MAX IN 850-700
MILLIBAR Q-VECTOR CONVERGENCE. MOISTURE LOOKS LIMITED. ADDED SOME
FLURRIES IN THE SOUTHWEST IN THE AFTERNOON TO MATCH UP WITH KDVN AND
KARX...BUT EVEN NEW 12Z ECMWF HAS TRENDED FURTHER SOUTHWEST THIS
FEATURE.
.LONG TERM...
.SUNDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
AN IMPULSE/VORTICITY MAX PROGGED BY MODELS TO SLIDE SOUTHEAST FROM
DAKOTAS TO ILLINOIS SUNDAY NIGHT. HOWEVER...MOSTLY CHANNELED
VORTICITY WITH THIS FEATURE. MODEL SOUNDINGS SUNDAY EVENING SUGGEST
SOME FLURRIES AT BEST....WILL BLEND IN WITH NEIGHBORS ON THE
FLURRIES SUNDAY EVENING.
BASIC COLD DRY NORTHWEST FLOW ALOFT MONDAY INTO TUESDAY NIGHT. CORE
OF COLDEST AIR AT 850 MB WILL ARRIVE IN WISCONSIN ON MONDAY WITH
-24C TO -26...SETTING UP THE COLDEST NIGHT OF THE WINTER SEASON FOR
MONDAY NIGHT INTO EARLY TUESDAY MORNING. PROGGED WIND CHILL VALUES
OF -20C TO -25C FOR MONDAY NIGHT UNTIL ABOUT 10 OR 11 AM CST TUESDAY
FOR SOUTHERN WISCONSIN WILL REQUIRE A WIND CHILL ADVISORY TO BE
ISSUED ON LATER SHIFTS. THIS ASSUMES FORECAST PANS OUT.
.WEDNESDAY AND WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SURFACE RIDGE WILL EXTEND FROM DAKOTAS TO THE TENNESSEE AREA...SO
QUIET AT THIS TIME. BOTH GFS AND ECMWF MODERATE 850 MB TEMPERATURES
TO -18C TO -20C BY 6 AM WED...SO SOMEWHAT WARMER SURFACE TEMPS
EXPECTED ON WEDNESDAY. HOWEVER...ECMWF BRINGS ANOTHER PUSH OF COLD
AIR DOWN INTO SOUTHERN WISCONSIN WEDNESDAY AFTERNOON. IN ANY
CASE...BOTH MODELS CONTINUE MODERATION TREND LATE WEDNESDAY NIGHT.
.THURSDAY AND FRIDAY...FORECAST CONFIDENCE IS LOW.
ON THURSDAY...MODELS SHOW ANOTHER SHORT-WAVE TROUGH DROPPING EAST
SOUTHEAST THROUGH THE WISCONSIN AREA. ASSOCIATED WARM-AIR ADVECTION
AND ISENTROPIC LIFT IN MID-LEVELS QUICKLY RESULTS IN CLOUDY SKIES
AND CHANCES OF SNOW BY LATE AFTERNOON...CONTINUING INTO THURSDAY
NIGHT. A SECONDARY SHORT-WAVE TROUGH ROTATES SOUTH OUT OF WESTERN
ONTARIO CANADA ON FRIDAY INTO GREAT LAKES REGION. THIS WILL CONTINUE
THE CHANCES OF SOME LIGHT SNOW INTO FRIDAY. MEANWHILE...SURFACE LOW
PRESSURE WILL MOVE NORTHEAST TO SOUTHERN OHIO BY FRIDAY MORNING PER
GFS...AND IN KENTUCKY PER ECMWF. 12Z GFS RUN THIS MORNING HAS THIS
LOW PRESSURE DEEPER THAN ECMWF...A FLIP-FLOP FROM 00Z RUN FRIDAY
EVENING WHICH HAD ECMWF WITH THE DEEPER SOLUTION. STAY TUNED.
&&
.AVIATION/00Z TAFS/...MAIN CONCERN WILL BE THE STRONG POST-FRONTAL
WINDS THAT ARRIVE VERY LATE THIS AFTERNOON/MORE LIKELY THIS EVENING
ACROSS SRN WI. NW WINDS OF 25-35 KNOTS LOOK LIKE A GOOD BET WITH
SOME GUSTS OVER 40 KNOTS. LOW LEVEL RH PROGS SUGGEST A GLANCING SHOT
OF STRATUS IN THE 6-12Z TIME FRAME TONIGHT IN THE COLD ADVECTION
REGIME...WITH A DRIER SIGNAL IN THE 12Z-00Z TIME FRAME ON SUNDAY.
GRADIENT SLACKENS FOR SUNDAY. WEAK VORT AXIS SLIDES THROUGH THOUGH
MOISTURE/LIFT LACKING. A FEW FLURRIES IN PARTS OF SC WI THOUGH ALL
MODELS KEEP QPF FURTHER SOUTHWEST OF THE AREA.
&&
.MARINE...NO CHANGES TO HEADLINES AT THIS POINT. HEAVY FREEZING
SPRAY AND GALE CONDITIONS LOOK VERY FAVORABLE TONIGHT AS STRONG COLD
FRONT PUSHES THROUGH THIS EVENING. ONCE GALE EXPIRES...SMALL CRAFT
WILL LIKELY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ046-047-056-057-
062-063-067-068.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ051-052-058>060-
064>066-069>072.
LM...HEAVY FREEZING SPRAY WARNING FROM MIDNIGHT TONIGHT TO NOON CST
SUNDAY FOR LMZ643>646.
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
GALE WARNING UNTIL 6 AM CST SUNDAY FOR LMZ643>646.
&&
$$
TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR
SUNDAY NIGHT THROUGH SATURDAY...KAPELA
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
218 PM CST SAT JAN 19 2013
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A
SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS
WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH
DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING
THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE
ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING
VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY
INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS
JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING
QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN
THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE
PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT
RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE
STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND
DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO
THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST
AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW
AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO
WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY
THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS
MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL
UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER
NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT
BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST
WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS.
HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW
ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A
RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN
CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE
SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE.
BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT
IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD
ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC
PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD
APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON
AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF
45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL
WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF
HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR
TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT
ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO
OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING
STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY
MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A
RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO
END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING
ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW
ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON
SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW
SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS
SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR
WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH
ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE
SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE
SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE
ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND
CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF
THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE
REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER
AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE
INDICATING A MODERATING TREND LATER NEXT WEEKEND.
ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS
WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS
SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT
VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT.
TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE
COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS
EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR.
LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH
THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME
DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT
TOO WESTERLY WIND DIRECTION.
TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A
CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS
THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY
NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH
HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM.
WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR
TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT
FAR OUT REASONABLE.
&&
.AVIATION...WHILE LIGHT MIXED PRECIPITATION HAS EXITED NORTHEAST
WISCONSIN...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN ARCTIC
COLD FRONTAL PASSAGE LATE THIS AFTERNOON AND THIS EVENING. SCT SNOW
SHOWERS ARE STILL EXPECTED TO DEVELOP ALONG THE FRONT...WITH LOCAL
VSBYS BLO 1SM. IN ADDITION...STRONG WEST WINDS WILL DEVELOP BEHIND
THE FRONT AS ARCTIC AIR POURS ACROSS THE STATE...WITH GUSTS TO 35 TO
40 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE LAKESHORE. LAKE EFFECT
SNOW SHOWERS WILL DEVELOP IN NC WI TONIGHT...AND NW WINDS WILL BE
STRONG ENOUGH TO CARRY SOME SNOW INTO RHI. IMPROVING CONDITIONS
WILL OCCUR AFTER MIDNIGHT IN TERMS OF DIMINISHING WINDS...SNOW
SHOWERS...AND INCREASING CIGS. VFR CONDITIONS TOMORROW UNDER ARCTIC
HIGH PRESSURE.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR
WIZ038>040-048>050.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-
045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ005-010-011-018-019-030-035-036.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR
WIZ022.
&&
$$
MPC/TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 AM CST SAT JAN 19 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
947 AM CST SAT JAN 19 2013
947 AM UPDATE...FORECAST IN GENERAL REMAINS ON TRACK. POTENT
SHORTWAVE WAS NOTED ON THE 15Z WATER VAPOR LOOP OVER SOUTHERN
MANITOBA...WITH A 120-140 KT JET AT THE TROPOPAUSE DIGGING INTO
THE DAKOTAS ON THE SOUTHWEST SIDE OF THE SHORTWAVE PER RAP
ANALYSIS. DPVA AHEAD OF THE SHORTWAVE HAS RESULTED IN A DEEPENING
SURFACE LOW...CURRENTLY AROUND 1002MB CENTERED OVER THE MN
ARROWHEAD. TRAILING THE LOW IS AN ARCTIC COLD FRONT ALONG THE
NORTH DAKOTA/SOUTH DAKOTA BORDER. SURFACE TEMPERATURES DROP FROM
THE MID TO UPPER 30S FROM SOUTH DAKOTA INTO THE FORECAST
AREA...INTO THE SINGLE DIGITS ABOVE ZERO OVER NORTHERN NORTH
DAKOTA. WITH THE RAPID DROP IN TEMPERATURES IS A 2 MB/HR PRESSURE
RISE OVER NORTH DAKOTA. THESE PRESSURE RISES AND A TIGHT PRESSURE
GRADIENT BEHIND THE ARCTIC FRONT HAS RESULTED IN WINDS GUSTING
30-50 KT ACROSS NORTH DAKOTA INTO FAR NORTHWEST MN. THERE ARE ALSO
SOME SNOW SHOWERS OCCURRING IMMEDIATELY BEHIND THE FRONT...AIDED
BY LOW LEVEL FRONTOGENESIS.
NAM/RAP/HRRR FORECASTS CONTINUE TO INDICATE THAT THE ARCTIC FRONT
WILL CROSS THE FORECAST AREA BETWEEN 21-00Z...WITH WINDS AND GUSTS
RAPIDLY INCREASING BEHIND THE FRONT AS INDICATED OVER NORTH
DAKOTA. INTERESTING TO SEE THAT AT 00Z...THE RAP WIND GUSTS SHOW
UPWARDS OF 40 KT OR SO ACROSS THE ENTIRE FORECAST AREA. NEEDLESS
TO SAY...THE WIND ADVISORY LOOKS SOLID. PLUS...THE SURFACE LOW
SHOULD BE ABLE TO DEEPEN A LITTLE MORE AS IT MOVES ACROSS THE
WARMER LAKE SUPERIOR WATER...AND HAS THE SYNOPTIC SCALE IMPACT TO
DEEPEN.
THERE ARE 2 ISSUES PRIOR TO THE ARCTIC FRONT ARRIVAL...THOUGH. THE
FIRST IS CLOUD COVER. FIRST BAND OF MID CLOUDS...ASSOCIATED WITH A
SHORTWAVE SEEN ON WATER VAPOR STRETCHING FROM NORTHEAST NEBRASKA
TO LA CROSSE...IS CLEARING OUT OF THE FORECAST AREA RIGHT NOW.
ANOTHER BATCH OF MID CLOUDS HAVE DEVELOPED OVER CENTRAL MN...AHEAD
OF ANOTHER WEAK SHORTWAVE. THESE CLOUDS APPEAR SLATED TO CROSS THE
FORECAST AREA DURING THE NEXT FEW HOURS. HAVE INCREASED CLOUD
COVER TO ACCOUNT FOR THESE. THERE STILL MAY BE ANOTHER BREAK IN
CLOUDS BEFORE THE ARCTIC FRONT ARRIVES. WITH THE IN-AND-OUT
PERIODS OF SUNSHINE AND 925MB TEMPS AROUND 5C PER 12Z MPX AND DVN
RAOBS...CONCERNED TEMPERATURES ARE NOT HIGH ENOUGH. HRRR ACTUALLY
HAS TEMPERATURES CLIMBING INTO THE LOW 50S OVER THE SOUTHERN HALF
OF THE FORECAST AREA. HRRR DID VERY WELL YESTERDAY...ALBEIT WE DID
HAVE FULL SUNSHINE. FOR NOW HAVE INCREASED TEMPERATURES
SLIGHTLY...MAINLY SOUTH OF I-90.
LASTLY...RAP AND 00Z/06Z NCEP HIRES ARW RUNS ARE IN GOOD AGREEMENT
SHOWING THE BAND OF SNOW SHOWERS OVER SOUTHERN NORTH DAKOTA POST-
FRONTAL DROPPING THROUGH MOST OF THE FORECAST AREA BETWEEN 18-00Z.
PREVIOUS FORECAST HAD THIS COVERED WELL...JUST GAVE A LITTLE MORE
TIMING AND SWITCHED TO A COVERAGE SNOW SHOWERS PHRASING SINCE
THERE IS A CONVECTIVE NATURE TO THE PRECIPITATION.
PREVIOUS DISCUSSION ISSUED AT 318 AM...
THE MAIN FOCUS IS ON THE DRASTIC CHANGES THAT ARE ON TAP FOR TODAY
AS A COLD FRONT DROPS THROUGH THE REGION.
CURRENTLY...BROAD CYCLONIC FLOW ALOFT IS IN PLACE THROUGH MUCH OF
CANADA AND THE US WITH THE CORE OF THE LOW CENTERED TO THE EAST OF
HUDSON BAY LEAVING THE UPPER MISSISSIPPI RIVER VALLEY IN
NORTHWESTERLY FLOW. DESPITE THIS...LOW LEVEL TEMPERATURES REMAIN
MILD AT THE MOMENT WITH A SURFACE LOW OVER EASTERN NORTH DAKOTA
AND A WARM FRONT EXTENDING TO THE EAST-SOUTHEAST ACROSS NORTHERN
WISCONSIN. THIS MORNING WILL END UP BEING THE WARMEST PART OF THE
DAY AS THIS SURFACE LOW TRACKS TO THE EAST TOWARD THE UP OF
MICHIGAN. THIS FEATURE WILL BRING A COLD FRONT THROUGH THE REGION
EARLY THIS AFTERNOON WITH WINDS SHIFTING TO THE NORTHWEST AND
BECOMING STRONG POST-FROPA. NOT A WHOLE LOT OF CHANGES TO THE
GOING WIND FORECAST WITH A TIGHTENING SURFACE PRESSURE
GRADIENT...STRONG LOW LEVEL COLD AIR ADVECTION AND 3HR PRESSURE
RISES OF 6-8MB SHOULD ALL LEAD TO STRONG AND GUSTY WINDS FOR A 6
TO 9 HOUR PERIOD LATE THIS AFTERNOON AND EVENING. SUBSIDENT AIR
SHOULD HELP TO MIX DOWN SOME HIGHER GUSTS IN THE 45-50MPH
RANGE...PARTICULARLY IN THE HIGHER ELEVATIONS IN SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. BASED ON ALL THIS...THE WIND
ADVISORY STILL LOOKS GOOD FOR THE REGION STARTING MID AFTERNOON
AND ENDING AROUND MIDNIGHT AS THE WINDS DIMINISH.
ANOTHER FEATURE WITH THIS FRONT IS THE BRIEF SHOT OF SNOW THAT
WILL COME WITH IT. THE 19.00Z NAM AND MESO-MODELS SHOW A BAND OF
SNOW FORMING OUT AHEAD OF THE COLD FRONT WHERE THE OVERALL FORCING
IS A LITTLE STRONGER ACROSS SOUTHEAST MINNESOTA AND NORTH CENTRAL
WISCONSIN. THIS WILL LEAD TO A SHORT PERIOD...LIKELY LESS THAN AN
HOUR...OF SNOW WHICH COULD BRIEFLY BE HEAVY. THIS COULD LEAD TO A
BRIEF DUSTING OF AROUND A HALF INCH OF SNOW AS IT COMES THROUGH.
KEPT SOME FLURRIES THROUGH THE NIGHT ACROSS MUCH OF THE REGION DUE
TO THE LOW LEVEL SATURATED LAYER BEING IN THE ICE LAYER OF -8C TO
-20C...THOUGH THEY MAY NOT OCCUR IF THE SUBSIDENCE IS TOO STRONG
AND CLEARS THINGS OUT.
ALTHOUGH WINDS WILL BE ON THE DECREASE AFTER MIDNIGHT...THEY WILL
STILL BE IN THE 10-20MPH RANGE AS THE COLDER AIR MOVES INTO THE
REGION. BASED ON THE TEMPERATURE/WIND FORECAST...THERE COULD BE
SOME -20F TO -25F WIND CHILLS THAT OCCUR ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS MAY WARRANT
THE NEED FOR A WIND CHILL ADVISORY ONCE THE WIND ADVISORY ENDS.
MAY STILL GO FOR ONE THIS MORNING...BUT AM STILL WORKING ON THE
COLLABORATION WITH NEIGHBORING OFFICES AT THE MOMENT ON WHETHER
TO GO FOR IT NOW OR LATER TODAY.
BEYOND THIS ITS ALL ABOUT HOW COLD TEMPERATURES WILL GET WITH
LITTLE TO NO SNOW PACK OUT THERE. A WEAKENING MID LEVEL TROUGH
THAT HAS LITTLE LOW LEVEL SUPPORT WILL MOVE THROUGH ON SUNDAY AND
COULD PROVIDE ANOTHER DUSTING OF SNOW...THOUGH CONFIDENCE IS NOT
VERY HIGH ON THIS WITH THE WEAK MID LEVEL LIFT. HAD THE SNOW PACK
NOT ERODED AWAY LAST WEEK...OUR TEMPERATURES WOULD LIKELY BE ABOUT
10 DEGREES COLDER THAN WHAT IS BEING FORECAST. DESPITE THIS...THE
GUIDANCE ALL REMAINS IN GOOD AGREEMENT OF HAVING SUB-ZERO
TEMPERATURES IN PLACE TO START NEXT WEEK. WIND CHILL ADVISORIES
WILL DEFINITELY BE NEEDED FROM MONDAY MORNING THROUGH TUESDAY
MORNING WITH WIND CHILLS IN THE -20F TO -30F RANGE.
.LONG TERM...TUESDAY THROUGH FRIDAY
318 AM CST SAT JAN 19 2013
THE COLD AIR MASS APPEARS TO REMAIN IN PLACE ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY THROUGH THE REST OF THE WEEK THOUGH IT
DOES MODERATE SOME GOING INTO WEDNESDAY AND BEYOND AS THE RIDGE
AXIS MOVES THROUGH AND THE CORE OF COLD LOW LEVEL AIR SHIFTS TO
THE EAST. THERE ARE SOME HINTS THAT A SYSTEM WILL DROP DOWN
THROUGH THE NORTHWEST FLOW ALOFT TUESDAY INTO TUESDAY NIGHT WHICH
COULD BRING SOME SNOW ALONG WITH IT. THE 19.00Z GFS IS THE ONLY
MODEL SHOWING THIS SNOW REACHING THE FORECAST AREA WITH THE 19.00Z
ECMWF PLACING THE SURFACE RIDGE RIGHT ALONG THE MISSISSIPPI RIVER.
SHOULD THE GFS PAN OUT...THERE COULD BE SOME HIGH RATIO SNOW THAT
OCCURS WITH 19.00Z BUFKIT SOUNDINGS SHOWING A DEEP DENDRITIC GROWTH
ZONE FROM THE SURFACE ON UP TO 700MB. THE BEST CHANCES FOR AN
ACCUMULATING SNOW IS WITH A SYSTEM THAT MAY COME IN ON THURSDAY OR
FRIDAY. THE 19.00Z GFS IS SLOW WITH THIS SYSTEM AND BRINGS IT IN
THURSDAY NIGHT INTO FRIDAY WHILE THE 19.00Z ECMWF HAS IT THROUGH
BY THURSDAY. THE 19.00Z GFS BUFKIT SOUNDINGS ARE EVEN DEEPER WITH
THE DENDRITIC GROWTH ZONE AND LIFT WITH THIS SYSTEM...WHICH COULD
AGAIN LEAD TO A HIGH SNOW TO LIQUID RATIO SNOW. TRENDED LOWER ON
TEMPERATURES ON THURSDAY WITH GUIDANCE SHOWING THIS SYSTEM
TRENDING A BIT FURTHER TO THE SOUTH.
&&
.AVIATION...THROUGH 18Z SUNDAY
1135 AM CST SAT JAN 19 2013
ARCTIC FRONT CONTINUES ITS MARCH TOWARDS THE TAF SITES AND AS OF
17Z STRETCHED FROM NEAR ABERDEEN SD TO DULUTH MN. AHEAD OF THE
FRONT...WINDS ARE TURNING WESTERLY AND SHOULD START GUSTING
SHORTLY TO 25 KT AT KRST DUE TO DAYTIME MIXING. KLSE IS A LITTLE
MORE PROTECTED BY THE VALLEY...BUT STILL BY 20Z ANTICIPATING
GUSTS TO DEVELOP THERE. VFR CONDITIONS ANTICIPATED UNTIL THE ARCTIC
FRONT ARRIVES DUE TO DRY LOW LEVEL AIR IN PLACE.
ARCTIC FRONT SHOULD REACH KRST AROUND 21Z AND KLSE AROUND 22Z.
IMMEDIATELY IN ITS WAKE...WINDS VEER TOWARDS THE NORTHWEST AND
RAPIDLY INCREASE. EXPECTING BOTH TAF SITES TO SEE SUSTAINED WINDS
OF 25-30 KT WITH GUSTS OF 40-45 KT WHICH WILL LAST THROUGH MUCH OF
THE EVENING. THE STRONG WINDS ARE A RESULT OF ARCTIC AIR
FLOWING...PRESSURES RISING RAPIDLY AND THE LOW PRESSURE AREA
RESPONSIBLE FOR A TIGHT PRESSURE GRADIENT OVER THE TAF SITES
DEEPENING AS IT CROSSES LAKE SUPERIOR. ALONG WITH THE FRONT WILL
COME A BAND OF MVFR STRATUS WITH SOME FLURRIES/SNOW SHOWERS.
VISIBILITIES MAY DROP TO IFR VERY BRIEFLY...BUT MVFR SEEMS MORE
LIKELY SINCE THE SNOW SHOWER COVERAGE SHOULD BE SCATTERED AT BEST.
KEPT THE TEMPO GROUP OF MVFR VISIBILITY TIL 00Z WHEN SNOW SHOWERS
ARE MOST LIKELY.
UPSTREAM...CLEARING CAN BE SEEN DROPPING INTO NORTHERN NORTH
DAKOTA. ANTICIPATING THIS TO REACH THE TAF SITES AROUND 06Z TO
HELP SCATTER OUT THE MVFR CLOUD DECK...LEADING TO VFR CONDITIONS
AFTERWARDS THROUGH 18Z SUNDAY. PLAN ON WINDS TO GRADUALLY DIMINISH
AS WELL BETWEEN 06-18Z SUNDAY...STAYING THE STRONGEST AT KLSE
BEING CLOSER TO THE SURFACE LOW AND FARTHEST AWAY FROM ARCTIC HIGH
PRESSURE BUILDING INTO WESTERN MINNESOTA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
551 AM CST SAT JAN 19 2013
WI...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR WIZ017-029-032>034-041>044-053>055-061.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ017-029.
MN...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR MNZ079-086>088-094>096.
IA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1130 AM CST SAT JAN 19 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW
AN AREA OF MIXED PRECIPITATION OVER NE WISCONSIN LATE THIS
MORNING. THIS PRECIPITATION SHOULD EXIT BY AROUND MIDDAY...BUT
COULD STILL LEAD TO SLICK ROADWAYS OVER DOOR COUNTY WHERE
TEMPERATURES ARE CURRENTLY IN THE UPPER 20S. LOOKING AHEAD...A
STRONG SHORTWAVE AND ARCTIC COLD FRONT ARE NOW MOVING QUICKLY EAST
OVER NORTHERN MINNESOTA. BOTH THE 12Z NAM AND RUC SHOW THESE
FEATURES REACHING NORTH-CENTRAL AND CENTRAL WISCONSIN AROUND
20-21Z AND NORTHEAST WISCONSIN BY AROUND 00Z. UPSTREAM OBS OVER
NORTH DAKOTA AND NORTHERN MINNESOTA SHOW OBS IN THE 1-3SM
RANGE...AND SUPPORT GOING WITH LIKELY SNOW SHOWERS OVER N-C
WISCONSIN LATE THIS AFTERNOON. ALSO HAVE OBSERVED SEVERAL WIND
GUSTS IN THE UPPER 30S TO LOWER 40S KTS BEHIND THE FRONT...WHERE A
STRONG ISALLOBARIC COMPONENT IS LEADING TO HIGHER GUSTS. SINCE THE
COLDER AIR BEHIND THE FRONT IS NOT PROGGED TO ARRIVE OVER THE FOX
VALLEY AND LAKESHORE UNTIL 00Z...HAVE DELAYED THE WIND ADVISORY
HEADLINES BY A FEW HOURS THERE. THE BEST PERIOD OF WIND IS DUE TO
ARRIVE LATE THIS AFTERNOON THROUGH LATE THIS EVENING WHEN THE
STRONGEST DESCENDING MOTION AND ISALLOBARIC PUSH ARRIVE. THINK
THE ADVISORY ENDING TIME IS A BIT TOO LONG...BUT WILL RE-EXAMINE
THAT LATER.
MPC
&&
.PREV DISCUSSION...ISSUED AT 625 AM CST SAT JAN 19 2013.
SHORT TERM...TODAY THROUGH SUNDAY...PCPN TRENDS...STRONG WINDS...
FALLING TEMPERATURES AND ASSOCIATED WIND ADVISORY/WIND
CHILL/MARINE HEADLINES ARE THE MAIN FCST CONCERNS.
CLIPPER LOW OVER NE ND/NW MN WILL TRACK THROUGH THE UPPER PENINSULA
OF MICHIGAN TODAY...AND DRAG AN ARCTIC COLD FRONT THROUGH THE FCST
AREA THIS AFTERNOON. SCT SNOW SHOWERS SEEN OVER THER MN ARROWHEAD
AND FAR NW WI SHOULD BRUSH THROUGH NORTHERN WI THIS MORNING...AND
ADDITIONAL SNOW SHOWERS WILL ACCOMPANY THE COLD FRONT THIS AFTERNOON.
ALTHOUGH MOISTURE IS LACKING WITH THIS SYSTEM...VERY STG DYNAMICS
ASSOC WITH A STG S/W TROF...THE LFQ OF AN UPPER LEVEL JET...DEEP
MID-LEVEL FRONTOGENTIC FORCING AND STEEP 850-700 MB LAPSE RATES
WILL HELP GENERATE SCT MODERATE SNOW SHOWERS ALONG THE FRONT THIS
AFTERNOON. THIS COULD END UP BEING A HISA (HIGH IMPACT SUB-ADVISORY)
EVENT...AS LOCALLY POOR VISIBILITIES WILL LIKELY OCCUR...AND WET
ROADS WILL QUICKLY FREEZE AS TEMPERATURES PLUMMET BEHIND THE
FRONT LATE THIS AFTERNOON. WILL MENTION THIS POSSIBILITY IN THE
HWO...AND ADD AN EXTRA PARAGRAPH ABOUT IT IN THE WIND ADVISORY
STATEMENT. THE DAY SHIFT CAN ISSUE AN SPS IF THE SNOW SHOWERS AND
TRAVEL CONCERNS DEVELOP AS EXPECTED. HAVE MAINTAINED LIKELY POPS
ACROSS NC WI FOR THIS AFTERNOON...WHERE MOST PLACES SHOULD PICK UP
AN INCH OR SO OF SNOW THIS AFTERNOON. LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN VILAS COUNTY.
PCPN TRENDS WILL TRANSITION TO MORE OF A TYPICAL NW FLOW LAKE EFFECT
PATTERN TONIGHT INTO SUNDAY. THE SETUP IS NEVER PERFECT FOR BIG
ACCUMS...AS THE WIND TRAJECTORY IS BIT TOO WESTERLY AT TIMES...STG
SUBSIDENCE OCCURS AT TIMES...AND LLVL TEMPS BECOME TOO COLD FOR
DENDRITES BY MID-EVENING TONIGHT. PLAN TO MENTION ADDITIONAL
ACCUMS OF 1 TO 3 INCHES IN VILAS COUNTY TONIGHT AND ANOTHER INCH
ON SUNDAY.
STG CAA AND SUBSIDENCE IN THE WAKE OF THE FRONT...COMBINED WITH
925 MB WINDS 40-45 KTS/850 MB WINDS OF 45-55 KT...AND STEEP LLVL
LAPSE RATES...SHOULD RESULT IN WIND GUSTS TO 45 TO 50 MPH ACROSS
MOST OF C/EC WI AND THE LAKESHORE LATE THIS AFTERNOON AND TONIGHT.
HAVE ISSUED A WIND ADVISORY FOR THIS AREA. THE WINDS WILL SUBSIDE
A BIT OVERNIGHT...BUT THE COMBINATION OF WIND/TEMPS WILL PRODUCE
WIND CHILLS AS COLD AS -25 OVER MUCH OF NC/C WI OVERNIGHT INTO
SUNDAY MORNING. HAVE ISSUED A WIND CHILL ADVISORY FOR THAT AREA.
LONG TERM...SUNDAY NGT THRU NEXT FRI. THE MAIN STORY FOR THE
FIRST PART OF THE EXTENDED FCST TO BE THE ARCTIC BLAST WHICH WL
SETTLE OVER THE REGION WITH THE COLDEST AIR THIS WINTER SEASON.
NOT UNTIL THE WRN CONUS UPR RDG BREAKS DOWN AT MID-WEEK WL THE
ARCTIC AIR BEGIN TO LEAVE WI...TO QUICKLY BE FOLLOWED BY A
RELATIVELY STRONG/FAST-MOVING SHORTWAVE TROF ACROSS THE NRN TIER
OF STATES. THIS SYSTEM WOULD IMPACT NE WI THU-THU NGT AND BRING
THE NEXT CHC FOR MEASURABLE SNOW. TEMPS BY LATE IN THE WORK WEEK
SHOULD AT LEAST APPROACH NORMAL ALTHO ANOTHER COOL DOWN IS HINTED
AT BY THE MDLS FOR NEXT WEEKEND.
ARCTIC AIR WL CONT TO POUR INTO THE GREAT LAKES SUNDAY NGT WITH 8H
TEMPS OVER NW WI APPROACHING -30C. THE PRESSURE GRADIENT IS STILL
FAIRLY TIGHT BETWEEN THE DEPARTED CLIPPER OVER SE CANADA AND STRONG
HI PRES OVER THE NRN/CNTRL PLAINS. EXPECT TO SEE WIND CHILL
HEADLINES TO BE ISSUED WITH MIN TEMPS RANGING FROM THE MID-TEENS
BELOW ZERO N-CNTRL TO AROUND ZERO LAKESIDE...COUPLED WITH W-NW
WINDS AROUND 10 MPH...TO SEND WIND CHILLS INTO THE -20 TO -32
DEGREE RANGE. THESE W-NW WINDS ARE NOT A FAVORABLE TRAJ FOR HEAVY
LAKE EFFECT SNOW SHWRS OVER VILAS CNTY...HOWEVER ANTICIPATE SEEING
AT LEAST SCT SNOW SHWR ACTIVITY REACH THE FAVORED SNOWBELT AREAS
OF THE CNTY WITH PERHAPS UP TO AN INCH OF ACCUMULATION.
LITTLE CHANGE EXPECTED SYNOPTICALLY SPEAKING HEADED INTO MON WITH
THE NW FLOW ALOFT AND THE ARCTIC AIR MASS LOCKED IN OVER THE
REGION. THE BETTER LAKE EFFECT SNOW WL CONT TO FAVOR NW/ERN 1/3 OF
UPR MI WITH ONLY SCT ACTIVITY AFFECTING VILAS CNTY. TEMPS WL
REMAIN THE BIG STORY AS MUCH OF N-CNTRL AND CNTRL WI WL NOT GET
OUR OF THE NEGATIVE NUMBERS (GENERALLY ZERO TO 5 BELOW). ON TOP OF
THE VERY COLD TEMPS WL BE A SUSTAINED W-NW WIND OF 10 TO 20 MPH
WHICH WOULD PLACE WIND CHILL READINGS AT -20 DEGS OR COLDER FOR
ALMOST THE ENTIRE FCST AREA...THUS HEADLINES BY NEED TO BE
EXTENDED RIGHT THRU MON.
THE AREA OF HI PRES IS FCST TO EXTEND FROM THE UPR MS VALLEY TO
THE OZARKS MON NGT WITH WINDS BACKING A BIT MORE TO A 280 OR 290
DEGREE DIRECTION WHICH IS EVEN MORE OF AN UNFAVORABLE TRAJ TO
BRING LAKE EFFECT INTO VILAS CNTY...THUS AM NOT EXPECTING MUCH (IF
ANY ACCUMULATION). THERE WL BE SOME WIND THRU THE NGT WHICH WOULD
HELP TO PREVENT TEMPS FROM COMPLETELY FREE-FALLING. EVEN SO...MON
NGT APPEARS TO BE THE COLDEST NGT WITH READINGS DROPPING TO NEAR
20 BELOW ZERO N-CNTRL...AROUND 5 BELOW ZERO ALONG THE LK MI
SHORELINE. ADD IN SOME WIND AND WE ARE LOOKING AT ADDITIONAL WIND
CHILL HEADLINES FOR ALL OF NE WI. THE HI PRES FINALLY REACHES THE
WRN GREAT LAKES REGION ON TUE WHICH SHOULD ALLOW FOR WINDS TO
LIGHTEN UP (GENERALLY IN THE 5-10 MPH RANGE). THIS SFC HI DOES NOT
HAVE A LOT OF DRY AIR WITH IT AS FCST SOUNDINGS INDICATE SEVERAL
LAYERS OF MOISTURE...THUS PARTLY SUNNY SKIES WOULD BE THE BEST
CASE SCENARIO. MAX TEMPS WL AGAIN STRUGGLE TO REACH ZERO...ESPECIALLY
AFTER THE BITTERLY COLD START TO THE DAY. MAY NEED TO TAKE VALUES
DOWN A DEGREE OR TWO FROM THE PREVIOUS FCST.
CHANGES IN THE OVERALL SYNOPTIC PATTERN BEGINS TUE NGT AS THE WRN
CONUS UPR RDG STARTS TO MOVE TOWARD THE ROCKIES AND WEAKEN A BIT.
ONE MORE VERY COLD NGT ANTICIPATED ACROSS NE WI WITH THE SFC HI
PRACTICALLY OVERHEAD (THUS LIGHT WINDS). LOOK FOR MIN TEMPS TO
RANGE FROM 10 BELOW TO 15 BELOW NORTH TO AROUND ZERO LAKESIDE.
SOME MODERATION IN TEMPS IS EXPECTED ON WED AS THE SFC HI SHIFTS
TO OUR EAST ALLOWING WINDS TO BACK W-SW AND THE CORE OF THE UPR
TROF PULLS FARTHER EAST. IN ADDITION...THE UPR RDG QUICKLY BREAKS
DOWN OVER THE ROCKIES ALLOWING FOR SOME MILDER PACIFIC AIR TO
BEGIN MOVING INTO THE CNTRL CONUS.
SINCE THE MEAN FLOW TO BECOME LESS AMPLIFIED WITH THE BREAK DOWN
OF THE UPR RDG...THIS WL ALLOW FOR A PACIFIC SYSTEM TO RACE EWD
ACROSS THE CONUS WED NGT INTO FRI. AS ONE WOULD EXPECT...THE MDLS
ARE HAVING SERIOUS TIMING ISSUES WITH THIS SYSTEM...AS WELL AS THE
TRACK OF THE ACCOMPANYING SFC LOW. SIMPLY TAKING A ROUGH AVERAGE
OF THE MDLS WOULD FAVOR THIS SYSTEM AFFECTING NE WI DURING THE THU-
THU NGT TIME FRAME WITH SOME MEASURABLE SNOW. AMOUNTS COULD BE
LIMITED DUE TO THE SPEED OF THE SYSTEM OVERALL...BUT WAY TOO EARLY
TO DETERMINE SNOW EXTENT JUST YET. TEMPS ARE PROGGED TO WARM INTO
THE TEENS TO LWR 20S FOR BOTH THU AND FRI...BUT THERE ARE SIGNS OF
ANOTHER UPR RDG BUILDING ACROSS THE WRN CONUS TOWARD NEXT WEEKEND
WHICH COULD DUMP ANOTHER COLD AIR MASS INTO THE GREAT LAKES. THIS
AIR MASS WHILE COLD...WL NOT BE ANYTHING COMPARED TO THE IMPENDING
ARCTIC BLAST FROM EARLIER IN THE WEEK.
&&
.AVIATION...WHILE LIGHT MIXED PRECIPITATION HAS EXITED NORTHEAST
WISCONSIN...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN ARCTIC
COLD FRONTAL PASSAGE LATE THIS AFTERNOON AND THIS EVENING. SCT SNOW
SHOWERS ARE STILL EXPECTED TO DEVELOP ALONG THE FRONT...WITH LOCAL
VSBYS BLO 1SM. IN ADDITION...STRONG WEST WINDS WILL DEVELOP BEHIND
THE FRONT AS ARCTIC AIR POURS ACROSS THE STATE...WITH GUSTS TO 35 TO
40 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE LAKESHORE. LAKE EFFECT
SNOW SHOWERS WILL DEVELOP IN NC WI TONIGHT...AND NW WINDS WILL BE
STRONG ENOUGH TO CARRY SOME SNOW INTO RHI. IMPROVING CONDITIONS
WILL OCCUR AFTER MIDNIGHT IN TERMS OF DIMINISHING WINDS...SNOW
SHOWERS...AND INCREASING CIGS. VFR CONDITIONS TOMORROW UNDER ARCTIC
HIGH PRESSURE.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR
WIZ038>040-048>050.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR WIZ030-031-035>037-045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ005-010-011-018-019-030-035-036.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR
WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1039 AM CST SAT JAN 19 2013
.UPDATE...THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW
AN AREA OF MIXED PRECIPITATION OVER NE WISCONSIN LATE THIS
MORNING. THIS PRECIPITATION SHOULD EXIT BY AROUND MIDDAY...BUT
COULD STILL LEAD TO SLICK ROADWAYS OVER DOOR COUNTY WHERE
TEMPERATURES ARE CURRENTLY IN THE UPPER 20S. LOOKING AHEAD...A
STRONG SHORTWAVE AND ARCTIC COLD FRONT ARE NOW MOVING QUICKLY EAST
OVER NORTHERN MINNESOTA. BOTH THE 12Z NAM AND RUC SHOW THESE
FEATURES REACHING NORTH-CENTRAL AND CENTRAL WISCONSIN AROUND
20-21Z AND NORTHEAST WISCONSIN BY AROUND 00Z. UPSTREAM OBS OVER
NORTH DAKOTA AND NORTHERN MINNESOTA SHOW OBS IN THE 1-3SM
RANGE...AND SUPPORT GOING WITH LIKELY SNOW SHOWERS OVER N-C
WISCONSIN LATE THIS AFTERNOON. ALSO HAVE OBSERVED SEVERAL WIND
GUSTS IN THE UPPER 30S TO LOWER 40S KTS BEHIND THE FRONT...WHERE A
STRONG ISALLOBARIC COMPONENT IS LEADING TO HIGHER GUSTS. SINCE THE
COLDER AIR BEHIND THE FRONT IS NOT PROGGED TO ARRIVE OVER THE FOX
VALLEY AND LAKESHORE UNTIL 00Z...HAVE DELAYED THE WIND ADVISORY
HEADLINES BY A FEW HOURS THERE. THE BEST PERIOD OF WIND IS DUE TO
ARRIVE LATE THIS AFTERNOON THROUGH LATE THIS EVENING WHEN THE
STRONGEST DESCENDING MOTION AND ISALLOBARIC PUSH ARRIVE. THINK
THE ADVISORY ENDING TIME IS A BIT TOO LONG...BUT WILL RE-EXAMINE
THAT LATER.
MPC
&&
.PREV DISCUSSION...ISSUED AT 625 AM CST SAT JAN 19 2013.
SHORT TERM...TODAY THROUGH SUNDAY...PCPN TRENDS...STRONG WINDS...
FALLING TEMPERATURES AND ASSOCIATED WIND ADVISORY/WIND
CHILL/MARINE HEADLINES ARE THE MAIN FCST CONCERNS.
CLIPPER LOW OVER NE ND/NW MN WILL TRACK THROUGH THE UPPER PENINSULA
OF MICHIGAN TODAY...AND DRAG AN ARCTIC COLD FRONT THROUGH THE FCST
AREA THIS AFTERNOON. SCT SNOW SHOWERS SEEN OVER THER MN ARROWHEAD
AND FAR NW WI SHOULD BRUSH THROUGH NORTHERN WI THIS MORNING...AND
ADDITIONAL SNOW SHOWERS WILL ACCOMPANY THE COLD FRONT THIS AFTERNOON.
ALTHOUGH MOISTURE IS LACKING WITH THIS SYSTEM...VERY STG DYNAMICS
ASSOC WITH A STG S/W TROF...THE LFQ OF AN UPPER LEVEL JET...DEEP
MID-LEVEL FRONTOGENTIC FORCING AND STEEP 850-700 MB LAPSE RATES
WILL HELP GENERATE SCT MODERATE SNOW SHOWERS ALONG THE FRONT THIS
AFTERNOON. THIS COULD END UP BEING A HISA (HIGH IMPACT SUB-ADVISORY)
EVENT...AS LOCALLY POOR VISIBILITIES WILL LIKELY OCCUR...AND WET
ROADS WILL QUICKLY FREEZE AS TEMPERATURES PLUMMET BEHIND THE
FRONT LATE THIS AFTERNOON. WILL MENTION THIS POSSIBILITY IN THE
HWO...AND ADD AN EXTRA PARAGRAPH ABOUT IT IN THE WIND ADVISORY
STATEMENT. THE DAY SHIFT CAN ISSUE AN SPS IF THE SNOW SHOWERS AND
TRAVEL CONCERNS DEVELOP AS EXPECTED. HAVE MAINTAINED LIKELY POPS
ACROSS NC WI FOR THIS AFTERNOON...WHERE MOST PLACES SHOULD PICK UP
AN INCH OR SO OF SNOW THIS AFTERNOON. LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN VILAS COUNTY.
PCPN TRENDS WILL TRANSITION TO MORE OF A TYPICAL NW FLOW LAKE EFFECT
PATTERN TONIGHT INTO SUNDAY. THE SETUP IS NEVER PERFECT FOR BIG
ACCUMS...AS THE WIND TRAJECTORY IS BIT TOO WESTERLY AT TIMES...STG
SUBSIDENCE OCCURS AT TIMES...AND LLVL TEMPS BECOME TOO COLD FOR
DENDRITES BY MID-EVENING TONIGHT. PLAN TO MENTION ADDITIONAL
ACCUMS OF 1 TO 3 INCHES IN VILAS COUNTY TONIGHT AND ANOTHER INCH
ON SUNDAY.
STG CAA AND SUBSIDENCE IN THE WAKE OF THE FRONT...COMBINED WITH
925 MB WINDS 40-45 KTS/850 MB WINDS OF 45-55 KT...AND STEEP LLVL
LAPSE RATES...SHOULD RESULT IN WIND GUSTS TO 45 TO 50 MPH ACROSS
MOST OF C/EC WI AND THE LAKESHORE LATE THIS AFTERNOON AND TONIGHT.
HAVE ISSUED A WIND ADVISORY FOR THIS AREA. THE WINDS WILL SUBSIDE
A BIT OVERNIGHT...BUT THE COMBINATION OF WIND/TEMPS WILL PRODUCE
WIND CHILLS AS COLD AS -25 OVER MUCH OF NC/C WI OVERNIGHT INTO
SUNDAY MORNING. HAVE ISSUED A WIND CHILL ADVISORY FOR THAT AREA.
LONG TERM...SUNDAY NGT THRU NEXT FRI. THE MAIN STORY FOR THE
FIRST PART OF THE EXTENDED FCST TO BE THE ARCTIC BLAST WHICH WL
SETTLE OVER THE REGION WITH THE COLDEST AIR THIS WINTER SEASON.
NOT UNTIL THE WRN CONUS UPR RDG BREAKS DOWN AT MID-WEEK WL THE
ARCTIC AIR BEGIN TO LEAVE WI...TO QUICKLY BE FOLLOWED BY A
RELATIVELY STRONG/FAST-MOVING SHORTWAVE TROF ACROSS THE NRN TIER
OF STATES. THIS SYSTEM WOULD IMPACT NE WI THU-THU NGT AND BRING
THE NEXT CHC FOR MEASURABLE SNOW. TEMPS BY LATE IN THE WORK WEEK
SHOULD AT LEAST APPROACH NORMAL ALTHO ANOTHER COOL DOWN IS HINTED
AT BY THE MDLS FOR NEXT WEEKEND.
ARCTIC AIR WL CONT TO POUR INTO THE GREAT LAKES SUNDAY NGT WITH 8H
TEMPS OVER NW WI APPROACHING -30C. THE PRESSURE GRADIENT IS STILL
FAIRLY TIGHT BETWEEN THE DEPARTED CLIPPER OVER SE CANADA AND STRONG
HI PRES OVER THE NRN/CNTRL PLAINS. EXPECT TO SEE WIND CHILL
HEADLINES TO BE ISSUED WITH MIN TEMPS RANGING FROM THE MID-TEENS
BELOW ZERO N-CNTRL TO AROUND ZERO LAKESIDE...COUPLED WITH W-NW
WINDS AROUND 10 MPH...TO SEND WIND CHILLS INTO THE -20 TO -32
DEGREE RANGE. THESE W-NW WINDS ARE NOT A FAVORABLE TRAJ FOR HEAVY
LAKE EFFECT SNOW SHWRS OVER VILAS CNTY...HOWEVER ANTICIPATE SEEING
AT LEAST SCT SNOW SHWR ACTIVITY REACH THE FAVORED SNOWBELT AREAS
OF THE CNTY WITH PERHAPS UP TO AN INCH OF ACCUMULATION.
LITTLE CHANGE EXPECTED SYNOPTICALLY SPEAKING HEADED INTO MON WITH
THE NW FLOW ALOFT AND THE ARCTIC AIR MASS LOCKED IN OVER THE
REGION. THE BETTER LAKE EFFECT SNOW WL CONT TO FAVOR NW/ERN 1/3 OF
UPR MI WITH ONLY SCT ACTIVITY AFFECTING VILAS CNTY. TEMPS WL
REMAIN THE BIG STORY AS MUCH OF N-CNTRL AND CNTRL WI WL NOT GET
OUR OF THE NEGATIVE NUMBERS (GENERALLY ZERO TO 5 BELOW). ON TOP OF
THE VERY COLD TEMPS WL BE A SUSTAINED W-NW WIND OF 10 TO 20 MPH
WHICH WOULD PLACE WIND CHILL READINGS AT -20 DEGS OR COLDER FOR
ALMOST THE ENTIRE FCST AREA...THUS HEADLINES BY NEED TO BE
EXTENDED RIGHT THRU MON.
THE AREA OF HI PRES IS FCST TO EXTEND FROM THE UPR MS VALLEY TO
THE OZARKS MON NGT WITH WINDS BACKING A BIT MORE TO A 280 OR 290
DEGREE DIRECTION WHICH IS EVEN MORE OF AN UNFAVORABLE TRAJ TO
BRING LAKE EFFECT INTO VILAS CNTY...THUS AM NOT EXPECTING MUCH (IF
ANY ACCUMULATION). THERE WL BE SOME WIND THRU THE NGT WHICH WOULD
HELP TO PREVENT TEMPS FROM COMPLETELY FREE-FALLING. EVEN SO...MON
NGT APPEARS TO BE THE COLDEST NGT WITH READINGS DROPPING TO NEAR
20 BELOW ZERO N-CNTRL...AROUND 5 BELOW ZERO ALONG THE LK MI
SHORELINE. ADD IN SOME WIND AND WE ARE LOOKING AT ADDITIONAL WIND
CHILL HEADLINES FOR ALL OF NE WI. THE HI PRES FINALLY REACHES THE
WRN GREAT LAKES REGION ON TUE WHICH SHOULD ALLOW FOR WINDS TO
LIGHTEN UP (GENERALLY IN THE 5-10 MPH RANGE). THIS SFC HI DOES NOT
HAVE A LOT OF DRY AIR WITH IT AS FCST SOUNDINGS INDICATE SEVERAL
LAYERS OF MOISTURE...THUS PARTLY SUNNY SKIES WOULD BE THE BEST
CASE SCENARIO. MAX TEMPS WL AGAIN STRUGGLE TO REACH ZERO...ESPECIALLY
AFTER THE BITTERLY COLD START TO THE DAY. MAY NEED TO TAKE VALUES
DOWN A DEGREE OR TWO FROM THE PREVIOUS FCST.
CHANGES IN THE OVERALL SYNOPTIC PATTERN BEGINS TUE NGT AS THE WRN
CONUS UPR RDG STARTS TO MOVE TOWARD THE ROCKIES AND WEAKEN A BIT.
ONE MORE VERY COLD NGT ANTICIPATED ACROSS NE WI WITH THE SFC HI
PRACTICALLY OVERHEAD (THUS LIGHT WINDS). LOOK FOR MIN TEMPS TO
RANGE FROM 10 BELOW TO 15 BELOW NORTH TO AROUND ZERO LAKESIDE.
SOME MODERATION IN TEMPS IS EXPECTED ON WED AS THE SFC HI SHIFTS
TO OUR EAST ALLOWING WINDS TO BACK W-SW AND THE CORE OF THE UPR
TROF PULLS FARTHER EAST. IN ADDITION...THE UPR RDG QUICKLY BREAKS
DOWN OVER THE ROCKIES ALLOWING FOR SOME MILDER PACIFIC AIR TO
BEGIN MOVING INTO THE CNTRL CONUS.
SINCE THE MEAN FLOW TO BECOME LESS AMPLIFIED WITH THE BREAK DOWN
OF THE UPR RDG...THIS WL ALLOW FOR A PACIFIC SYSTEM TO RACE EWD
ACROSS THE CONUS WED NGT INTO FRI. AS ONE WOULD EXPECT...THE MDLS
ARE HAVING SERIOUS TIMING ISSUES WITH THIS SYSTEM...AS WELL AS THE
TRACK OF THE ACCOMPANYING SFC LOW. SIMPLY TAKING A ROUGH AVERAGE
OF THE MDLS WOULD FAVOR THIS SYSTEM AFFECTING NE WI DURING THE THU-
THU NGT TIME FRAME WITH SOME MEASURABLE SNOW. AMOUNTS COULD BE
LIMITED DUE TO THE SPEED OF THE SYSTEM OVERALL...BUT WAY TOO EARLY
TO DETERMINE SNOW EXTENT JUST YET. TEMPS ARE PROGGED TO WARM INTO
THE TEENS TO LWR 20S FOR BOTH THU AND FRI...BUT THERE ARE SIGNS OF
ANOTHER UPR RDG BUILDING ACROSS THE WRN CONUS TOWARD NEXT WEEKEND
WHICH COULD DUMP ANOTHER COLD AIR MASS INTO THE GREAT LAKES. THIS
AIR MASS WHILE COLD...WL NOT BE ANYTHING COMPARED TO THE IMPENDING
ARCTIC BLAST FROM EARLIER IN THE WEEK.
&&
.AVIATION...LOW CLOUDS REMAINED ACROSS FAR NORTHERN WI EARLY THIS
MORNING...AND SCT SNOW SHOWERS WILL LIKELY IMPACT THAT AREA THIS
MORNING. HOWEVER...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN
ARCTIC COLD FRONTAL PASSAGE THIS AFTERNOON. SCT SNOW SHOWERS WILL
DEVELOP ALONG THE FRONT...WITH LOCAL VSBYS BLO 1SM. IN ADDITION...
STRONG WEST WINDS WILL DEVELOP LATE THIS AFTERNOON AND TONIGHT...
WITH GUSTS TO 35 TO 45 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE
LAKESHORE. LAKE EFFECT SNOW SHOWERS WILL DEVELOP IN NC WI LATER
TODAY INTO TONIGHT...ESPECIALLY ACROSS VILAS COUNTY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR
WIZ038>040-048>050.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR WIZ030-031-035>037-045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ005-010-011-018-019-030-035-036.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR
WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
947 AM CST SAT JAN 19 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
947 AM CST SAT JAN 19 2013
947 AM UPDATE...FORECAST IN GENERAL REMAINS ON TRACK. POTENT
SHORTWAVE WAS NOTED ON THE 15Z WATER VAPOR LOOP OVER SOUTHERN
MANITOBA...WITH A 120-140 KT JET AT THE TROPOPAUSE DIGGING INTO
THE DAKOTAS ON THE SOUTHWEST SIDE OF THE SHORTWAVE PER RAP
ANALYSIS. DPVA AHEAD OF THE SHORTWAVE HAS RESULTED IN A DEEPENING
SURFACE LOW...CURRENTLY AROUND 1002MB CENTERED OVER THE MN
ARROWHEAD. TRAILING THE LOW IS AN ARCTIC COLD FRONT ALONG THE
NORTH DAKOTA/SOUTH DAKOTA BORDER. SURFACE TEMPERATURES DROP FROM
THE MID TO UPPER 30S FROM SOUTH DAKOTA INTO THE FORECAST
AREA...INTO THE SINGLE DIGITS ABOVE ZERO OVER NORTHERN NORTH
DAKOTA. WITH THE RAPID DROP IN TEMPERATURES IS A 2 MB/HR PRESSURE
RISE OVER NORTH DAKOTA. THESE PRESSURE RISES AND A TIGHT PRESSURE
GRADIENT BEHIND THE ARCTIC FRONT HAS RESULTED IN WINDS GUSTING
30-50 KT ACROSS NORTH DAKOTA INTO FAR NORTHWEST MN. THERE ARE ALSO
SOME SNOW SHOWERS OCCURRING IMMEDIATELY BEHIND THE FRONT...AIDED
BY LOW LEVEL FRONTOGENESIS.
NAM/RAP/HRRR FORECASTS CONTINUE TO INDICATE THAT THE ARCTIC FRONT
WILL CROSS THE FORECAST AREA BETWEEN 21-00Z...WITH WINDS AND GUSTS
RAPIDLY INCREASING BEHIND THE FRONT AS INDICATED OVER NORTH
DAKOTA. INTERESTING TO SEE THAT AT 00Z...THE RAP WIND GUSTS SHOW
UPWARDS OF 40 KT OR SO ACROSS THE ENTIRE FORECAST AREA. NEEDLESS
TO SAY...THE WIND ADVISORY LOOKS SOLID. PLUS...THE SURFACE LOW
SHOULD BE ABLE TO DEEPEN A LITTLE MORE AS IT MOVES ACROSS THE
WARMER LAKE SUPERIOR WATER...AND HAS THE SYNOPTIC SCALE IMPACT TO
DEEPEN.
THERE ARE 2 ISSUES PRIOR TO THE ARCTIC FRONT ARRIVAL...THOUGH. THE
FIRST IS CLOUD COVER. FIRST BAND OF MID CLOUDS...ASSOCIATED WITH A
SHORTWAVE SEEN ON WATER VAPOR STRETCHING FROM NORTHEAST NEBRASKA
TO LA CROSSE...IS CLEARING OUT OF THE FORECAST AREA RIGHT NOW.
ANOTHER BATCH OF MID CLOUDS HAVE DEVELOPED OVER CENTRAL MN...AHEAD
OF ANOTHER WEAK SHORTWAVE. THESE CLOUDS APPEAR SLATED TO CROSS THE
FORECAST AREA DURING THE NEXT FEW HOURS. HAVE INCREASED CLOUD
COVER TO ACCOUNT FOR THESE. THERE STILL MAY BE ANOTHER BREAK IN
CLOUDS BEFORE THE ARCTIC FRONT ARRIVES. WITH THE IN-AND-OUT
PERIODS OF SUNSHINE AND 925MB TEMPS AROUND 5C PER 12Z MPX AND DVN
RAOBS...CONCERNED TEMPERATURES ARE NOT HIGH ENOUGH. HRRR ACTUALLY
HAS TEMPERATURES CLIMBING INTO THE LOW 50S OVER THE SOUTHERN HALF
OF THE FORECAST AREA. HRRR DID VERY WELL YESTERDAY...ALBEIT WE DID
HAVE FULL SUNSHINE. FOR NOW HAVE INCREASED TEMPERATURES
SLIGHTLY...MAINLY SOUTH OF I-90.
LASTLY...RAP AND 00Z/06Z NCEP HIRES ARW RUNS ARE IN GOOD AGREEMENT
SHOWING THE BAND OF SNOW SHOWERS OVER SOUTHERN NORTH DAKOTA POST-
FRONTAL DROPPING THROUGH MOST OF THE FORECAST AREA BETWEEN 18-00Z.
PREVIOUS FORECAST HAD THIS COVERED WELL...JUST GAVE A LITTLE MORE
TIMING AND SWITCHED TO A COVERAGE SNOW SHOWERS PHRASING SINCE
THERE IS A CONVECTIVE NATURE TO THE PRECIPITATION.
PREVIOUS DISCUSSION ISSUED AT 318 AM...
THE MAIN FOCUS IS ON THE DRASTIC CHANGES THAT ARE ON TAP FOR TODAY
AS A COLD FRONT DROPS THROUGH THE REGION.
CURRENTLY...BROAD CYCLONIC FLOW ALOFT IS IN PLACE THROUGH MUCH OF
CANADA AND THE US WITH THE CORE OF THE LOW CENTERED TO THE EAST OF
HUDSON BAY LEAVING THE UPPER MISSISSIPPI RIVER VALLEY IN
NORTHWESTERLY FLOW. DESPITE THIS...LOW LEVEL TEMPERATURES REMAIN
MILD AT THE MOMENT WITH A SURFACE LOW OVER EASTERN NORTH DAKOTA
AND A WARM FRONT EXTENDING TO THE EAST-SOUTHEAST ACROSS NORTHERN
WISCONSIN. THIS MORNING WILL END UP BEING THE WARMEST PART OF THE
DAY AS THIS SURFACE LOW TRACKS TO THE EAST TOWARD THE UP OF
MICHIGAN. THIS FEATURE WILL BRING A COLD FRONT THROUGH THE REGION
EARLY THIS AFTERNOON WITH WINDS SHIFTING TO THE NORTHWEST AND
BECOMING STRONG POST-FROPA. NOT A WHOLE LOT OF CHANGES TO THE
GOING WIND FORECAST WITH A TIGHTENING SURFACE PRESSURE
GRADIENT...STRONG LOW LEVEL COLD AIR ADVECTION AND 3HR PRESSURE
RISES OF 6-8MB SHOULD ALL LEAD TO STRONG AND GUSTY WINDS FOR A 6
TO 9 HOUR PERIOD LATE THIS AFTERNOON AND EVENING. SUBSIDENT AIR
SHOULD HELP TO MIX DOWN SOME HIGHER GUSTS IN THE 45-50MPH
RANGE...PARTICULARLY IN THE HIGHER ELEVATIONS IN SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. BASED ON ALL THIS...THE WIND
ADVISORY STILL LOOKS GOOD FOR THE REGION STARTING MID AFTERNOON
AND ENDING AROUND MIDNIGHT AS THE WINDS DIMINISH.
ANOTHER FEATURE WITH THIS FRONT IS THE BRIEF SHOT OF SNOW THAT
WILL COME WITH IT. THE 19.00Z NAM AND MESO-MODELS SHOW A BAND OF
SNOW FORMING OUT AHEAD OF THE COLD FRONT WHERE THE OVERALL FORCING
IS A LITTLE STRONGER ACROSS SOUTHEAST MINNESOTA AND NORTH CENTRAL
WISCONSIN. THIS WILL LEAD TO A SHORT PERIOD...LIKELY LESS THAN AN
HOUR...OF SNOW WHICH COULD BRIEFLY BE HEAVY. THIS COULD LEAD TO A
BRIEF DUSTING OF AROUND A HALF INCH OF SNOW AS IT COMES THROUGH.
KEPT SOME FLURRIES THROUGH THE NIGHT ACROSS MUCH OF THE REGION DUE
TO THE LOW LEVEL SATURATED LAYER BEING IN THE ICE LAYER OF -8C TO
-20C...THOUGH THEY MAY NOT OCCUR IF THE SUBSIDENCE IS TOO STRONG
AND CLEARS THINGS OUT.
ALTHOUGH WINDS WILL BE ON THE DECREASE AFTER MIDNIGHT...THEY WILL
STILL BE IN THE 10-20MPH RANGE AS THE COLDER AIR MOVES INTO THE
REGION. BASED ON THE TEMPERATURE/WIND FORECAST...THERE COULD BE
SOME -20F TO -25F WIND CHILLS THAT OCCUR ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS MAY WARRANT
THE NEED FOR A WIND CHILL ADVISORY ONCE THE WIND ADVISORY ENDS.
MAY STILL GO FOR ONE THIS MORNING...BUT AM STILL WORKING ON THE
COLLABORATION WITH NEIGHBORING OFFICES AT THE MOMENT ON WHETHER
TO GO FOR IT NOW OR LATER TODAY.
BEYOND THIS ITS ALL ABOUT HOW COLD TEMPERATURES WILL GET WITH
LITTLE TO NO SNOW PACK OUT THERE. A WEAKENING MID LEVEL TROUGH
THAT HAS LITTLE LOW LEVEL SUPPORT WILL MOVE THROUGH ON SUNDAY AND
COULD PROVIDE ANOTHER DUSTING OF SNOW...THOUGH CONFIDENCE IS NOT
VERY HIGH ON THIS WITH THE WEAK MID LEVEL LIFT. HAD THE SNOW PACK
NOT ERODED AWAY LAST WEEK...OUR TEMPERATURES WOULD LIKELY BE ABOUT
10 DEGREES COLDER THAN WHAT IS BEING FORECAST. DESPITE THIS...THE
GUIDANCE ALL REMAINS IN GOOD AGREEMENT OF HAVING SUB-ZERO
TEMPERATURES IN PLACE TO START NEXT WEEK. WIND CHILL ADVISORIES
WILL DEFINITELY BE NEEDED FROM MONDAY MORNING THROUGH TUESDAY
MORNING WITH WIND CHILLS IN THE -20F TO -30F RANGE.
.LONG TERM...TUESDAY THROUGH FRIDAY
318 AM CST SAT JAN 19 2013
THE COLD AIR MASS APPEARS TO REMAIN IN PLACE ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY THROUGH THE REST OF THE WEEK THOUGH IT
DOES MODERATE SOME GOING INTO WEDNESDAY AND BEYOND AS THE RIDGE
AXIS MOVES THROUGH AND THE CORE OF COLD LOW LEVEL AIR SHIFTS TO
THE EAST. THERE ARE SOME HINTS THAT A SYSTEM WILL DROP DOWN
THROUGH THE NORTHWEST FLOW ALOFT TUESDAY INTO TUESDAY NIGHT WHICH
COULD BRING SOME SNOW ALONG WITH IT. THE 19.00Z GFS IS THE ONLY
MODEL SHOWING THIS SNOW REACHING THE FORECAST AREA WITH THE 19.00Z
ECMWF PLACING THE SURFACE RIDGE RIGHT ALONG THE MISSISSIPPI RIVER.
SHOULD THE GFS PAN OUT...THERE COULD BE SOME HIGH RATIO SNOW THAT
OCCURS WITH 19.00Z BUFKIT SOUNDINGS SHOWING A DEEP DENDRITIC GROWTH
ZONE FROM THE SURFACE ON UP TO 700MB. THE BEST CHANCES FOR AN
ACCUMULATING SNOW IS WITH A SYSTEM THAT MAY COME IN ON THURSDAY OR
FRIDAY. THE 19.00Z GFS IS SLOW WITH THIS SYSTEM AND BRINGS IT IN
THURSDAY NIGHT INTO FRIDAY WHILE THE 19.00Z ECMWF HAS IT THROUGH
BY THURSDAY. THE 19.00Z GFS BUFKIT SOUNDINGS ARE EVEN DEEPER WITH
THE DENDRITIC GROWTH ZONE AND LIFT WITH THIS SYSTEM...WHICH COULD
AGAIN LEAD TO A HIGH SNOW TO LIQUID RATIO SNOW. TRENDED LOWER ON
TEMPERATURES ON THURSDAY WITH GUIDANCE SHOWING THIS SYSTEM
TRENDING A BIT FURTHER TO THE SOUTH.
&&
.AVIATION...TODAY AND TONIGHT
551 AM CST SAT JAN 19 2013
ALL EYES ARE ON AN ARCTIC COLD FRONT THAT WILL BLAST THROUGH THE
AREA THIS AFTERNOON. UNTIL THEN...EXPECT PATCHY ALTOCUMULUS WITH
BASES AOA 10KFT. LOOK FOR SOUTHWEST WINDS IN ADVANCE OF THE FRONT
THIS MORNING...THEN SHIFTING TO THE NORTHWEST AND INCREASING INTO
THE 25-35KT RANGE WITH GUSTS INTO THE 40-45KT RANGE AROUND 21Z.
THIS FRONTAL PASSAGE IS ALSO EXPECTED TO PRODUCE MVFR CLOUDS ALONG
WITH SCATTERED SNOW SHOWER ACTIVITY. THESE STRONG WINDS AND
LOCALLY REDUCED VISIBILITIES IN SCATTERED SNOW SHOWER ACTIVITY WILL
LIKELY POSE PROBLEMS FOR BOTH GROUND AND AIRCRAFT OPERATIONS. LOOK
FOR THE STRONG/GUSTY NORTHWEST WINDS TO SUBSIDE AFTER MIDNIGHT
ALONG WITH SCATTERING CLOUDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
551 AM CST SAT JAN 19 2013
WI...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR WIZ017-029-032>034-041>044-053>055-061.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ017-029.
MN...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR MNZ079-086>088-094>096.
IA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
421 PM MST SUN JAN 20 2013
.AVIATION...00Z TAFS
LATEST HRRR MODEL RUN SHOWS IFR CEILINGS RETURNING TO KAIA AND
KCDR SHORTLY AFTER SUNSET. WRF SOUNDINGS FOR KCDR SHOWING A FAIRLY
STRONG STRATUS/FOG INVERSION SETTING UP OVER CHADRON AROUND 03Z
OR SO AND PERSISTING THROUGH MONDAY MORNING. CONFIDENCE IS HIGH
THAT EITHER FOG OR STRATUS WILL REDEVELOP OVER KCDR. WITH THE HRRR
SHOWING THIS STRATUS SPREADING SOUTH...TOOK KAIA DOWN SHORTLY
AFTER 03Z OR SO. ALSO NEED TO WATCH KSNY AS THE HRR SHOWS THE
SOUTHERN PANHANDLE GOING DOWN AFTER 05Z OR SO. FOR OUR SOUTHEAST
WYOMING AIRPORTS...VFR CONDITIONS WILL CONTINUE. THE EXCEPTION
COULD BE DOUGLAS WHERE THE BACKDOOR FRONT COULD PUSH INTO AND
DEVELOP SOME IFR/MVFR.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 247 PM MST SUN JAN 20 2013/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
UPCOMING WEEK CHARACTERIZED AS WINDY. TWO POSSIBLE HIGH WIND
EVENTS LOOK TO TAKE SHAPE THIS WEEK. A PESKY BACKDOOR COLD FRONT
HANGS ACROSS EASTERN PORTIONS OF THE CWA AFFECTING TEMPERATURES
MAINLY. THESE ARE THE FORECAST CHALLENGES WITH THIS FORECAST
PACKAGE.
CURRENTLY...BACKDOOR COLD FRONT HAS PUSHED SOUTHWEST THIS MORNING
AND CURRENTLY LAYS UP ALONG THE EASTERN SLOPES OF THE LARAMIE
RANGE EARLY THIS AFTERNOON. BEHIND THE FRONT...BLUSTERY NORTHEASTERLY
WINDS...COLDER TEMPERATURES ARE OCCURRING ACROSS SOUTHEAST WYOMING
EAST OF THE LARAMIE RANGE...WITH STRATUS OUT OVER THE NORTHERN
PANHANDLE. TEMPERATURES AT CHADRON AT 1 PM ARE BEING REPORTED AT
22 DEGREES WITH LOW 30S HERE AT CHEYENNE AND DOUGLAS. STRATUS LINE
CAN BE SEEN ON SATELLITE IMAGERY...GENERALLY FROM NEAR
BRIDGEPORT...NORTHWEST TO JUST NORTH OF TORRINGTON TO AROUND BILL
IN CONVERSE COUNTY.
FRONT LOOKS TO REMAIN IN PLACE THIS EVENING WITH COLD NORTH TO
NORTHEASTERLY WINDS EAST OF THE LARAMIE RANGE. OVERNIGHT LOWS WILL
BE QUITE COLD...WITH NEAR ZERO LOWS ACROSS THE NORTHERN PANHANDLE
AND LOW TEENS ALONG THE LARAMIE RANGE. FRONT REALLY DOES NOT BEGIN
TO MOVE EAST UNTIL MONDAY MID MORNING...BUT TAKES ITS SWEET TIME
EXITING THE NORTHERN PANHANDLE. MODEL SOUNDING TONIGHT SHOW A
PRETTY STRONG INVERSION SETTING UP OVER THE NORTHERN PANHANDLE AND
NIOBRARA COUNTY...SO WENT AHEAD AND KEPT INHERITED PATCHY FOG IN
THE FORECAST FOR THIS AREA.
A PRETTY STRONG GRADIENT IS SET UP FOR MONDAY WITH THE SLOW
MOVEMENT OF THIS FRONT. THE LATEST NAM/WRF WRKHGT PRODUCT SHOWING
THE CRAIG TO CASPER 850MB GRADIENT AROUND AT 65 METERS BY 06Z
TOMORROW NIGHT...700MB GRADIENT AROUND 51 METERS. GFS 700MB WINDS
INCREASE TO 50-55 KT MONDAY NIGHT. THOUGH NOT THE BEST WIND
DIRECTIONS FOR HIGH WINDS...DO BELIEVE THERE IS A GOOD POSSIBILITY
OF A GAP WIND EVENT SETTING UP FOR OUR WIND PRONE AREAS MONDAY
NIGHT INTO TUESDAY...SO WILL GO AHEAD WITH A HIGH WIND WATCH FOR
OUR WIND PRONE AREAS. MID SHIFT CAN TAKE ANOTHER LOOK BEFORE
ISSUING ANY UPGRADES.
BACKDOOR FRONT FINALLY MOVES EAST TUESDAY MORNING AND WINDS EASE
SOME THROUGH THE DAY. STILL LOOKS LIKE A COLD DAY OVERALL FOR THE
NORTHERN PANHANDLE TUESDAY WITH UPPER 30S AND LOW 40S FOR HIGHS.
ELSEWHERE...A BEAUTIFUL DAY LOOKS TO BE IN STORE WITH MID 50S
ACROSS THE SOUTHERN PANHANDLE ALL THE WAY TO THE EAST SLOPES OF
THE LARAMIE RANGE.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
THE 12Z MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT. A SHORTWAVE
RIDGE AXIS WILL SHIFT EAST ACROSS THE CWA WEDNESDAY...FOLLOWED BY
A SHORTWAVE TROUGH WEDNESDAY NIGHT AND THURSDAY MORNING. THE FAST
LOW-MID LEVEL TROPOSPHERIC FLOW AND LARGE SURFACE PRESSURE GRADIENT
ASSOCIATED WITH A STRONG COLD FRONT WILL PRODUCE MORE WIDESPREAD
STRONG AND GUSTY SURFACE WINDS AT THAT TIME. 700MB WINDS INCREASE
TO 70 KT OVER SOUTHEAST WYOMING AND 55 KT OVER THE WESTERN NEBRASKA
PANHANDLE WEDNESDAY EVENING. WINDS DECREASE THURSDAY WITH THE
PASSAGE OF THE UPPER TROUGH AND SURFACE COLD FRONT.
HIGH TEMPERATURES WEDNESDAY WILL BE 10 TO 20 DEGREES ABOVE NORMAL...
COOLING TO NEAR NORMAL THURSDAY AS CANADIAN HIGH PRESSURE BUILDS
SOUTHEAST ACROSS THE NORTHERN PLAINS. SURFACE TROUGH ALONG THE
LARAMIE RANGE THURSDAY NIGHT SHIFTS EAST INTO THE WESTERN NEBRASKA
PANHANDLE FRIDAY. A SURFACE RIDGE WILL BE PARKED OVER THE WASATCH
RANGE. WESTERLY SURFACE WINDS WILL BE BREEZY OVER THE MOUNTAINS AT
THAT TIME.
700MB TEMPERATURES MODERATE FROM -12C THURSDAY TO -2C FRIDAY.
DOWNSLOPE FLOW ON THE EASTERN PLAINS WILL RESULT IN 40-DEGREE
TEMPERATURES...WITH SOME 30S LINGERING IN EAST CENTRAL WYOMING AND
THE NORTHERN PANHANDLE. EVEN MILDER TEMPERATURES ARE IN THE FORECAST
FOR THE UPCOMING WEEKEND FOR THE EASTERN PLAINS AND PANHANDLE WITH
HIGHS IN THE 50S TO NEAR 60. IT WILL BE BREEZY OVER THE MOUNTAINS.
PRECIPITATION CHANCES DURING THE ENTIRE PERIOD WILL BE SLIM TO
NONE WITH LIMITED MOISTURE AND JET DYNAMICS WELL NORTH OF THE CWA.
AVIATION...18Z TAF ISSUANCE...
COLD FRONT HAS PUSHED THROUGH ALL EXCEPT AREAS WEST OF THE LARAMIE
RANGE LATE THIS MORNING. SURFACE WINDS SHIFTED FROM WESTERLY TO
NORTHERLY BEHIND THE FRONT AND WERE GUSTING AS HIGH AS 25 KT. A
LOW CLOUD DECK WAS PUSHING SOUTH ACROSS EASTERN WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE. CEILINGS RANGED FROM HIGH END IFR TO
MVFR. PREVAILING MVFR CEILINGS ARE FORECAST AT CHADRON AND ALLIANCE
THROUGH TONIGHT. VFR CONDITIONS WILL PREVAIL FOR THE SOUTHEAST
WYOMING AERODROMES THROUGH TONIGHT...WITH GUSTY WESTERLY WINDS
DEVELOPING MONDAY MORNING.
FIRE WEATHER...
STRONG AND GUSTY WINDS ARE THE THEME FOR FIRE WEATHER THIS WEEK.
WINDS WILL EASE SOME THIS EVENING AFTER SUNSET WITH OVERNIGHT
HUMIDITIES RANGING FROM 70 PERCENT OUT BY RAWLINS TO 100 PERCENT
IN THE PANHANDLE. STRONG WINDS EXPECTED MONDAY NIGHT INTO TUESDAY
IN OUR WIND PRONE AREAS WITH AFTERNOON HUMIDITIES FALLING INTO THE
LOW TEENS EAST OF THE LARAMIE RANGE TUESDAY AFTERNOON. A STRONGER
AND MORE WIDESPREAD HIGH WIND EVENT LOOKS TO TAKE SHAPE WEDNESDAY
NIGHT INTO THURSDAY AS A COLD FRONT PASSES THROUGH THE AREA AND
LOW PRESSURE TRACKS THROUGH MONTANA. WIDESPREAD WIND GUSTS IN
EXCESS OF 60 MPH ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY...
BEFORE SHIFTING NORTHWEST AND EASING THURSDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM 9 PM MONDAY TO 8 AM TUESDAY FOR WYZ106-
WYZ110-WYZ116.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...CLAYCOMB
LONG TERM/AVIATION...JAMSKI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
340 AM CST MON JAN 21 2013
.DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* BRIEF PERIOD OF PATCHY MVFR CIGS IN 2500-3000 FT RANGE EARLY
THIS MORNING...WITH A FEW FLURRIES OR LIGHT SNOW SHOWERS.
* GUSTY WEST-NORTHWEST WINDS TO 25 KTS THROUGH THE DAY.
RATZER
//DISCUSSION...UPDATED 09Z...
PATCHY MVFR CIGS 2500-3000 FT WITH LIGHT SNOW SHOWERS/FLURRIES
HAVE SPREAD EAST ACROSS THE IL TERMINALS AS EXPECTED. EXPECT THESE
CONDITIONS TO PERSIST FOR A FEW HOURS THROUGH SUNRISE THIS MORNING
BEFORE LARGE SCALE SUBSIDENCE DEVELOPS AND SCATTERS LOWER CLOUDS
BY MID-MORNING. WINDS ALREADY COMING UP A BIT WITH COLDER LOW
LEVEL AIR MOVING IN...WITH SOME GUSTS 15-20 KTS LIKELY PRIOR TO
SUNRISE.
RATZER
PREVIOUS DISCUSSION FROM 06Z...
FORECAST AREA REMAINS IN REGION OF CYCLONIC LOW LEVEL FLOW TO THE
EAST OF A SURFACE RIDGE AXIS ACROSS THE PLAINS...AND SOUTH OF A
WEAK LOW PRESSURE TROUGH OVER THE NORTHERN LAKES AND ONTARIO.
COLD...DRY ARCTIC AIR CONTINUES TO SPILL INTO THE REGION FROM THE
NORTHWEST. NORTHWEST FLOW ALOFT IS PLAYING HOST TO A SERIES OF
SHEARED UPPER LEVEL DISTURBANCES...AND ONE SUCH SYSTEM WILL DIG
SOUTHEAST ACROSS THE FORECAST AREA THIS MORNING. ENHANCED AREA OF
LOW LEVEL LIFT AHEAD OF THIS DISTURBANCE WAS PRODUCING AN AREA OF
LOWER CLOUDS ACROSS EASTERN IA AND SOUTHWEST WI AT 0530Z...WHICH
WILL MOVE EAST-SOUTHEAST ACROSS THE TERMINALS OVER THE NEXT
SEVERAL HOURS. DRYNESS OF THE LOW LEVEL ARCTIC AIR MASS WAS MAKING
COVERAGE OF THE LOWER CLOUD LAYERS SOMEWHAT PATCHY...THOUGH IT
DOES APPEAR THAT A PERIOD OF 2500-3000 FT MVFR CIGS AND A FEW
FLURRIES WILL PROPAGATE ACROSS NORTHERN IL AND NORTHWEST INDIANA
THROUGH SUNRISE. ONCE THE UPPER WAVE PASSES...SUBSIDENCE SHOULD
SCATTER OUT THE CLOUD COVER WITH VFR CONDITIONS EXPECTED THROUGH
REMAINDER OF THE TAF PERIOD.
THE SURFACE PRESSURE GRADIENT WILL TIGHTEN A BIT WITH A RENEWED
PUSH OF LOW LEVEL COLD AIR TODAY. WIND DIRECTION SHOULD REMAIN
FAIRLY STEADY IN THE 280-300 DEG RANGE...WITH CURRENT SPEEDS OF
AROUND 10 KTS INCREASING TO AROUND 15 KT AND GUSTING AROUND 25 KT
AFTER ABOUT 12-13Z. WIND GUSTS WILL SLOWLY TAIL OFF TONIGHT.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-HIGH CONFIDENCE IN BRIEF MVFR CIGS/FLURRIES THIS AM.
* HIGH CONFIDENCE ALL OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...CHC SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHC SNOW. MVFR/IFR POSSIBLE.
SATURDAY...VFR.
BMD
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014...6 PM MONDAY TO 9 AM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
335 AM CST MON JAN 21 2013
...UPDATED LONG TERM DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 219 AM CST MON JAN 21 2013
A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION HAS RESULTED
IN AN ARCTIC AIR INTRUSION INTO THE NORTHERN PLAINS EARLY THIS
MORNING. THERE WERE TWO FRONTAL SURGES, ONE THAT PASSED LATE SUNDAY
AFTERNOON THROUGH WESTERN KANSAS, AND A MORE PRONOUNCED FRONT
LOCATED ACROSS CENTRAL NEBRASKA AS OF 2 AM. THIS 2ND COLDER SURGE
WILL NOT MAKE IT THROUGH WESTERN KANSAS TODAY. HOWEVER, A PATCH OF
LOW LEVEL MOISTURE AND LOW CLOUDS, WITH CEILINGS AROUND 1000FT WAS
TRAPPED ACROSS WEST CENTRAL KANSAS NEAR THE SURFACE RIDGE IN THE WAKE
OF THE FIRST FRONT. WEAK LEE TROUGHING IS EXPECTED TO DEVELOP TODAY
AS A SMALL COMPONENT OF MID-LEVEL FLOW ACROSS THE ROCKIES RESULTS
IN PRESSURE FALLS. THIS WOULD TYPICALLY CLEAR THE CLOUDS OUT OF
WESTERN KANSAS. HOWEVER, THERE IS A CHANCE THAT A SHARP LOW-LEVEL
INVERSION WILL DEVELOP AND PERSIST IN SPITE OF THE DAYTIME
HEATING. THE 00Z AND 06Z NAM SHOW NO SIGN OF THIS SCENARIO, WITH
TEMPERATURES IN THE MID 40S AT PLACES LIKE SCOTT CITY AND DIGHTON.
BUT THE 05Z RAP SHOWS A SMALL POCKET OF COLDER AIR, WITH HIGHS
STAYING IN THE MID TO UPPER 30S THERE, WITH 40S FURTHER EAST AND
NEAR 50 IN FAR SOUTHWEST KANSAS. THIS IS A DEPARTURE FROM THE 03Z
RAP WHICH WAS SIMILAR TO THE NAM. SO THE MAIN FORECAST PROBLEM
THIS MORNING IS WHETHER LOW CLOUDS WILL PERSIST ACROSS WEST
CENTRAL KANSAS, ALONG WITH THE COOLER TEMPERATURES. WE OPTED TO GO
GENERALLY WITH A NAM SOLUTION, EXCEPT KEEP TEMPERATURES SEVERAL
DEGREES COOLER WHERE THE RAP IS SHOWING THE LOW LEVEL COLD POOL.
IT IS POSSIBLE THAT GIVEN THE DEVELOPING LOW LEVEL SOUTH TO
SOUTHWEST WINDS THAT THE COLD POOL MAY SHIFT NORTH OF INTERSTATE
70 BY LATE AFTERNOON.
A NORTHWEST TO SOUTHEAST ORIENTED BAROCLINIC ZONE WILL REMAIN ACROSS
THE CENTRAL AND EASTERN PLAINS TONIGHT AS THE AFOREMENTIONED
SECONDARY COLD FRONT STALLS OUT FROM WESTERN NEBRASKA INTO EASTERN
KANSAS. ANY REMAINING LOW CLOUDS SHOULD CLEAR, EXCEPT FOR POSSIBLY A
FEW HIGHER LEVEL CLOUDS. TEMPERATURES SHOULD FALL INTO THE UPPER TEENS
TO LOWER 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CST MON JAN 21 2013
THE UPPER LEVEL LOW PRESSURE SYSTEM CENTERED OVER THE HUDSON BAY
REGION WILL MIGRATE EAST INTO THE CANADIAN MARITIME LATER THIS WEEK
WHICH WILL ALLOW HEIGHTS TO RISE SOMEWHAT OVER THE EASTERN PART OF
THE U.S. FARTHER WEST, A PERSISTENT UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL CONTINUE IN PLACE OVER THE WEST COAST. A SHORTWAVE
TROUGH WILL PLOW THROUGH THE UPPER RIDGE AND MOVE OUT OVER THE
NORTHERN AND CENTRAL PLAINS ON THURSDAY. THE OPERATIONAL GFS IS A
LITTLE SLOWER THAN THE OTHER MODELS WITH THE TIMING OF THIS FEATURE.
THE GFS ENSEMBLE MEMBERS TEND TO BE FASTER THAN THE OPERATIONAL RUN
SO WILL LEAN TOWARD THE EURO AND CANADIAN SOLUTIONS.
A WARMING TREND WILL BE IN PROGRESS FROM TUESDAY INTO WEDNESDAY AS
UPPER LEVEL RIDGING BUILDS INTO THE CENTRAL PLAINS. THE MODELS SHOW
A WEAK FRONTAL BOUNDARY PUSHING SOUTHWESTWARD INTO THE HIGH PLAINS
WEDNESDAY AFTERNOON IN RESPONSE TO A SHORTWAVE TROUGH MOVING THROUGH
THE UPPER MIDWEST AND GREAT LAKES. TEMPERATURES SHOULD BE ABLE TO
RISE INTO THE LOWER 50S AROUND HAYS WITH HIGHS CLIMBING INTO THE MID
60S AT ELKHART. THE NEXT COLD FRONT WILL BE PUSHING SOUTH ACROSS
SOUTHWEST KANSAS ON THURSDAY. THIS WILL DROP TEMPERATURES BACK SOME
ON THURSDAY. ANOTHER SURGE OF EVEN COLDER AIR WILL BE MOVING DOWN
THROUGH THE MIDWEST ON THURSDAY NIGHT BUT THE BULK OF THIS SHOULD
STAY IN EASTERN KANSAS.
THE MODELS SHOW THE UPPER FLOW BECOMING MORE ZONAL ONCE AGAIN BY THE
UPCOMING WEEKEND. DOWNSLOPE FLOW WILL BRING WARMER TEMPERATURES BACK
OUT ACROSS THE HIGH PLAINS WHICH SHOULD ALLOW TEMPERATURES TO WARM
BACK INTO THE 50S AND POSSIBLY THE LOW 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1143 PM CST SUN JAN 20 2013
A PATCH OF MVFR CIGS OVER KGCK WILL GRADUALLY ERODE THROUGH 09Z AS
THE FLOW JUST ABOVE THE SURFACE BECOMES DOWNSLOPE AND SURFACE
WINDS BECOME LIGHT. OTHERWISE, VFR CONDITIONS WILL PERSIST AT
GCK/HYS. A LEE TROUGH WILL DEVELOP BETWEEN 15 AND 18Z, RESULTING
IN A WINDSHIFT TO THE SOUTHWEST AT 10-12KTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 21 48 25 / 0 0 0 0
GCK 44 20 51 24 / 0 0 0 0
EHA 50 26 58 29 / 0 0 0 0
LBL 47 24 54 26 / 0 0 0 0
HYS 38 17 42 21 / 0 0 0 0
P28 40 21 47 27 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...GERARD
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
309 AM CST MON JAN 21 2013
.DISCUSSION...
SHORT TERM FORECAST (TODAY AND TUESDAY)...
COLD AIR CONTINUES TO TRICKLE INTO THE FORECAST AREA THIS MORNING AS
THE 8Z RAP INDICATES AN AREA OF SURFACE HIGH PRESSURE STRETCHING
FROM THE CENTRAL PLAINS NORTHWESTWARD INTO CENTRAL CANADA. THIS HIGH
PRESSURE IS BRINGING LIGHT NORTHWEST WINDS...WHICH IS ALLOWING THE
COLD AIR TO ADVECT INTO THE AREA. 11-3.9 MICRON SATELLITE SHOWS AN
AREA OF STRATUS STRETCHING FROM KFNB NORTHWESTWARD THROUGH CENTRAL
NEBRASKA AND INTO SOUTHWESTERN SOUTH DAKOTA. OBSERVATIONS FROM
CENTRAL NEBRASKA UNDER THIS STRATUS ARE INDICATING LIGHT SNOW
FALL. AS THE STRATUS STRETCHES SOUTHEASTWARD INTO NORTHEAST KANSAS
IT MAY BRING WITH IT A FEW SNOW FLURRIES...MAINLY NORTH OF
INTERSTATE 70. FORECAST SOUNDINGS THROUGHOUT THE DAY SHOW A
MODEST AMOUNT OF UPWARD MOTION IN THE LOWEST FEW THOUSAND
FEET...WHICH WILL AID IN STRATUS DEVELOPMENT AND WITH THE COLUMN
BEING SO COLD IT WILL NOT TAKE MUCH LIFT NOR FURTHER COOLING TO
PRODUCE A FEW FLURRIES. EXPECT SCATTERED OFF-AND-ON FLURRIES TO
REMAIN POSSIBLE THROUGH THE DAYTIME AND OVERNIGHT HOURS ON
MONDAY/MONDAY NIGHT. DUE TO THE CLOUD COVER AND COLD AIR ADVECTION
DO NOT EXPECT TEMPERATURES ON MONDAY TO WARM MUCH...AS THE GOING
HIGH FOR MONDAY WILL BE IN THE LOWER TO MID 20S NORTH OF
INTERSTATE 70 AND IN THE LOWER 30S SOUTH OF I-70. DRY AIR WORKS
ITS WAY INTO THE AREA BY MONDAY NIGHT CAUSING THE STRATUS TO MOVE
TO THE EAST BY MONDAY NIGHT ALLOWING SKIES TO CLEAR BY TUESDAY. IT
WILL TAKE ANOTHER DAY TO GET THE COLD AIR OUT OF THE AREA...SO FOR
TUESDAY EXPECTING ONLY A MINOR INCREASE IN TEMPS...AS DAY TIME
HIGHS FOR TUESDAY WILL REACH NO HIGHER THAN THE LOWER TO MID
30S...WITH POSSIBLY 40 DEGREE TEMPS IN CENTRAL KANSAS.
MID RANGE AND EXTENDED FORECAST (WEDNESDAY THROUGH SUNDAY)...
WEDNESDAY WILL BRING A BRIEF BREAK FROM THE ARCTIC AIR AS WARMER
AIR TRIES TO MAKE ITS WAY INTO THE FORECAST AREA. 925 MB TEMPS GO
FROM -10 TO -15 C ON TUESDAY TO AROUND 5 C WEDNESDAY...WHICH IF
MIXED TO THE SURFACE SHOULD BRING TEMPS BACK INTO THE MID TO UPPER
40S ON WED. PERHAPS AREAS OF CENTRAL AND EAST CENTRAL KANSAS COULD
SEE SOME 50 TO 53 DEGREE TEMPS WED. BY THURSDAY ANOTHER COLD AIR
MASS PLUNGES INTO THE CENTRAL PLAINS CAUSING TEMPS TO RETURN TO
NEAR NORMAL FOR THURSDAY THROUGH SATURDAY...WITH FRIDAY STRUGGLING
TO REACH THE 30S. WARM AIR ADVECTION ON THURSDAY EVENING/THURSDAY
NIGHT WILL BRING INCREASING CLOUDS...AND PERHAPS SOME VERY LIGHT
RAIN IN FAR EAST CENTRAL KANSAS. WITH SURFACE TEMPS DROPPING NEAR
FREEZING AND PERHAPS BELOW FREEZING THURSDAY NIGHT THERE COULD BE
A PERIOD OF VERY LIGHT FREEZING RAIN...BUT THAT PERIOD SHOULD NOT
LAST LONG...NOR IS ANY ACCUMULATION EXPECTED.
A WARM UP FROM THE COLD TEMPS IS EXPECTED BY THE END OF THE WEEKEND
AS FORECAST HIGHS FOR SUNDAY LOOK LIKE THEY WILL REACH THE LOWER TO
POSSIBLY MID 50S AS WARM AIR MOVES BACK INTO THE AREA AND MID LEVEL
RIDGING TAKES OVER. BY EARLY NEXT WEEK WITH INCREASING MID LEVEL
HEIGHTS MOVING OVER THE AREA AND A WESTERLY DOWN SLOPE FLOW THE
LATTER HALF OF THE WEEKEND AND EARLY PART OF NEXT WEEK LOOK FAIRLY
PLEASANT.
JL
&&
.AVIATION...
EXPECT GENERALLY VFR CONDITIONS THROUGH THE FORECAST. CIGS 3500FT
AGL EXPECTED AFTER SUNRISE AND COULD APPROACH HIGH END MVFR. WINDS
VEER AND BECOME MORE EASTERLY THROUGH THE FORECAST. 67
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
256 AM CST MON JAN 21 2013
...UPDATED FOR SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 219 AM CST MON JAN 21 2013
A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION HAS RESULTED
IN AN ARCTIC AIR INTRUSION INTO THE NORTHERN PLAINS EARLY THIS
MORNING. THERE WERE TWO FRONTAL SURGES, ONE THAT PASSED LATE SUNDAY
AFTERNOON THROUGH WESTERN KANSAS, AND A MORE PRONOUNCED FRONT
LOCATED ACROSS CENTRAL NEBRASKA AS OF 2 AM. THIS 2ND COLDER SURGE
WILL NOT MAKE IT THROUGH WESTERN KANSAS TODAY. HOWEVER, A PATCH OF
LOW LEVEL MOISTURE AND LOW CLOUDS, WITH CEILINGS AROUND 1000FT WAS
TRAPPED ACROSS WEST CENTRAL KANSAS NEAR THE SURFACE RIDGE IN THE WAKE
OF THE FIRST FRONT. WEAK LEE TROUGHING IS EXPECTED TO DEVELOP TODAY
AS A SMALL COMPONENT OF MID-LEVEL FLOW ACROSS THE ROCKIES RESULTS
IN PRESSURE FALLS. THIS WOULD TYPICALLY CLEAR THE CLOUDS OUT OF
WESTERN KANSAS. HOWEVER, THERE IS A CHANCE THAT A SHARP LOW-LEVEL
INVERSION WILL DEVELOP AND PERSIST IN SPITE OF THE DAYTIME
HEATING. THE 00Z AND 06Z NAM SHOW NO SIGN OF THIS SCENARIO, WITH
TEMPERATURES IN THE MID 40S AT PLACES LIKE SCOTT CITY AND DIGHTON.
BUT THE 05Z RAP SHOWS A SMALL POCKET OF COLDER AIR, WITH HIGHS
STAYING IN THE MID TO UPPER 30S THERE, WITH 40S FURTHER EAST AND
NEAR 50 IN FAR SOUTHWEST KANSAS. THIS IS A DEPARTURE FROM THE 03Z
RAP WHICH WAS SIMILAR TO THE NAM. SO THE MAIN FORECAST PROBLEM
THIS MORNING IS WHETHER LOW CLOUDS WILL PERSIST ACROSS WEST
CENTRAL KANSAS, ALONG WITH THE COOLER TEMPERATURES. WE OPTED TO GO
GENERALLY WITH A NAM SOLUTION, EXCEPT KEEP TEMPERATURES SEVERAL
DEGREES COOLER WHERE THE RAP IS SHOWING THE LOW LEVEL COLD POOL.
IT IS POSSIBLE THAT GIVEN THE DEVELOPING LOW LEVEL SOUTH TO
SOUTHWEST WINDS THAT THE COLD POOL MAY SHIFT NORTH OF INTERSTATE
70 BY LATE AFTERNOON.
A NORTHWEST TO SOUTHEAST ORIENTED BAROCLINIC ZONE WILL REMAIN ACROSS
THE CENTRAL AND EASTERN PLAINS TONIGHT AS THE AFOREMENTIONED
SECONDARY COLD FRONT STALLS OUT FROM WESTERN NEBRASKA INTO EASTERN
KANSAS. ANY REMAINING LOW CLOUDS SHOULD CLEAR, EXCEPT FOR POSSIBLY A
FEW HIGHER LEVEL CLOUDS. TEMPERATURES SHOULD FALL INTO THE UPPER TEENS
TO LOWER 20S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 PM CST SUN JAN 20 2013
NORTHWEST FLOW ALOFT WILL CONTINUE ACROSS WESTERN KANSAS THROUGH
WEDNESDAY NIGHT DUE TO A PERSISTENT MID TO UPPER LEVEL LONG WAVE
TROUGH LOCATED ACROSS THE EASTERN CONUS AND A MID TO UPPER LEVEL
RIDGE OF HIGH PRESSURE ACROSS THE WESTERN CONUS. SURFACE HIGH
PRESSURE WILL GENERALLY BE LOCATED EAST OF THE FORECAST AREA DURING
THIS TIME FRAME AND WITH NORTHWEST FLOW ALOFT, NO SIGNIFICANT
WEATHER IS EXPECTED WITH MOSTLY CLEAR SKIES AND DRY CONDITIONS. LOWS
TUESDAY AND WEDNESDAY MORNING ARE FORECASTED TO DIP INTO THE LOWER
TO MID 20S. HIGHS TUESDAY ARE ANTICIPATED TO RANGE FROM THE MID 40S
ACROSS CENTRAL KANSAS TO UPPER 50S ACROSS FAR SOUTHWEST KANSAS.
HIGHS WEDNESDAY ARE EXPECTED TO BE SLIGHTLY WARMER AND RANGE FORM
AROUND 50 DEGREES ACROSS CENTRAL KANSAS TO LOWER 60S ACROSS FAR
SOUTHWESTERN KANSAS.
THE WEATHER PATTERN CHANGES WEDNESDAY NIGHT THROUGH THURSDAY AS A
MID TO UPPER LEVEL SHORTWAVE MOVES DOWN FROM WESTERN CANADA AND INTO
THE NORTHERN PLAINS. THIS WILL HELP PUSH A SURFACE COLD FRONT
THROUGH WESTERN KANSAS SOMETIME WEDNESDAY NIGHT INTO THURSDAY
MORNING. NO SIGNIFICANT WEATHER IS ANTICIPATED WITH THIS SYSTEM DUE
TO THE LACK OF DEEP MOISTURE, HOWEVER, MID TO HIGH LEVEL CLOUDS WILL
INCREASE IN COVERAGE. BREEZY NORTHERLY WINDS ARE EXPECTED BEHIND
THIS FRONT THURSDAY MORNING INTO THURSDAY AFTERNOON. LOWS THURSDAY
MORNING LOOK TO RANGE FROM THE UPPER 20S ACROSS WEST CENTRAL KANSAS
TO MID 30S ACROSS THE KS/OK BORDER. HIGHS THURSDAY AFTERNOON ARE
FORECASTED TO RANGE FROM THE MID 40S ACROSS CENTRAL KANSAS TO LOWER
50S ELSEWHERE.
TRANQUIL WEATHER IS ANTICIPATED FRIDAY INTO THIS WEEKEND AS MID TO
UPPER LEVEL RIDGING BUILDS ACROSS THE SOUTHERN ROCKIES AND HIGH
PRESSURE AT THE SURFACE POSITIONS ITSELF SOUTH OF THE FORECAST AREA.
A GRADUAL WARMING TREND IS FORECASTED WITH HIGHS IN THE 40S FRIDAY
AND LOWER 50S SATURDAY. LOWS FRIDAY AND SATURDAY MORNING WILL
GENERALLY BE IN THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1143 PM CST SUN JAN 20 2013
A PATCH OF MVFR CIGS OVER KGCK WILL GRADUALLY ERODE THROUGH 09Z AS
THE FLOW JUST ABOVE THE SURFACE BECOMES DOWNSLOPE AND SURFACE
WINDS BECOME LIGHT. OTHERWISE, VFR CONDITIONS WILL PERSIST AT
GCK/HYS. A LEE TROUGH WILL DEVELOP BETWEEN 15 AND 18Z, RESULTING
IN A WINDSHIFT TO THE SOUTHWEST AT 10-12KTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 21 49 25 / 0 0 0 0
GCK 44 20 51 23 / 0 0 0 0
EHA 50 26 57 28 / 0 0 0 0
LBL 47 24 54 26 / 0 0 0 0
HYS 38 17 44 21 / 0 0 0 0
P28 40 21 48 26 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...HOVORKA_42
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1234 AM EST MON JAN 21 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A HIGH AMPLITUDE PATTERN
OVER NAMERICA WITH A RIDGE ALONG THE W COAST THRU AK AND A DEEP TROF
COVERING MUCH OF CNTRL/ERN CANADA INTO THE NCNTRL CONUS/GREAT LAKES.
BEHIND LAST NIGHTS SHORTWAVE PASSAGE...INCREASINGLY COLDER ARCTIC
AIR IS FLOWING INTO THE AREA. LATEST RUC ANALYSIS SHOWS 850MB TEMPS
OF -22 TO -24C OVER UPPER MI/LAKE SUPERIOR. UPSTREAM 850MB TEMPS ON
12Z ROABS WERE -25C/-26C/-27C AT KINL/CWPL/CYQD RESPECTIVELY.
FARTHER UPSTREAM...POOL OF SUB -30C AIR AT 850MB IS JUST NW OF CYQD
AS 00Z RAOB AT CYSM SHOWED -34C AT 850MB. THAT CORE OF ARCTIC AIR
WILL BE SETTLING INTO THE UPPER LAKES MON/MON NIGHT BEHIND SHORTWAVE
CURRENTLY DROPPING SSE THRU MANITOBA. ANOTHER WEAKER SHORTWAVE IS
PASSING THRU THE UPPER GREAT LAKES ATTM. HOWEVER...WAVE HAS HAD NO
DISCERNIBLE INFLUENCE ON LES PER RADAR IMAGERY. MOST INTENSE LES
BAND IS STREAMING INTO WRN ALGER COUNTY AS LAND BREEZE COMPONENT
STRENGTHENS CONVERGENCE OFF MARQUETTE COUNTY. TO THE W...WIND
PARALLEL LES BANDS ARE STREAMING INTO WRN UPPER MI. WEBCAMS SHOW
HIGHLY VARIABLE VIS AS -SHSN PASS. SINCE ARCTIC AIR HAS PUSHED DGZ
TO NEAR THE SFC...SNOWFLAKE SIZE IS SMALL...MAKING THE -SHSN VERY
EFFECTIVE AT REDUCING VIS. THIS IS ALSO KEEPING NEW SNOW
ACCUMULTIONS ON THE LIGHT SIDE OVER THE W.
AFOREMENTIONED SHORTWAVE IN MANITOBA WILL DROP ACROSS THE UPPER
LAKES OVERNIGHT TONIGHT THRU MON MORNING. FORCING ASSOCIATED WITH
WAVE PER DEEP LAYER QVECTOR CONVERGENCE WILL GIVE A BOOST TO LES
TONIGHT THRU MID MORNING MON AS MOISTURE DEPTH INCREASES AND
INVERSION RISES TO AROUND 10KFT. NORMALLY WITH SUCH SYNOPTIC
ENHANCEMENT...WOULD BE CONCERNED ABOUT A SIGNIFICANT INCREASE IN HVY
LES/SNOW ACCUMULATIONS. HOWEVER...WITH INCREASINGLY COLDER AIR
CONTINUING TO PUSH DGZ TOWARD THE SFC OR MORE LIKELY ELIMINATING IT
ALTOGETHER...SNOW ACCUMULATIONS WILL BE LIMITED BY SMALL SNOWFLAKE
SIZE. ONLY AREAS LIKELY TO SEE MORE SIGNIFICANT SNOW ACCUMULATIONS
WILL BE THOSE THAT ARE IMPACTED BY LES WITHIN STRONGER CONVERGENCE
ZONES AS THE CONVERGENCE WILL PROVIDE AN OPPORTUNITY FOR MORE
SIGNIFICANT LAKE MODERATION AND THUS POSSIBLY RAISE DGZ INTO A
PORTION OF THE CONVECTIVE LAYER. THOSE ENHANCED CONVERGENCE ZONES
WILL BE DIFFICULT TO PIN DOWN EXACTLY...BUT THERE SHOULD BE 2 OR 3.
ONE SHOULD OCCUR IN ONTONAGON COUNTY...PROBABLY AROUND THE VCNTY OF
THE PORCUPINE MTNS DUE TO STRENGTHENING LAND BREEZE OFF NW WI. THE
OTHERS SHOULD BE IN ERN ALGER COUNTY AND A PORTION OF LUCE COUNTY
DUE TO STRENGTHENING LAND BREEZES OFF MARQUETTE/WRN ALGER COUNTY AND
ALSO OFF ONTARIO. ALL HIGH RES MODEL GUIDANCE POINT TOWARD THE
PROGRESSING LAND BREEZES OVER SCNTRL/ERN LAKE SUPERIOR LEADING TO
EITHER MESO LOW DEVELOPMENT OR SHARP SFC TROFFING SOMEWHERE IN THE
AREA BTWN GRAND MARAIS/CARIBOU ISLAND AND WHITEFISH PT. IF A MESO
LOW DEVELOPS FAR ENOUGH OFFSHORE...IT`S POSSIBLE MOST OF THE LES
WILL ALSO SHIFT OFFSHORE. IF A SHARP CONVERGENCE ZONE DEVELOPS...
MDT/HVY LES COULD STREAM ONSHORE INTO A SMALL PART OF ERN ALGER/NW
LUCE FOR SEVERAL HRS. WITH PASSAGE OF SHORTWAVE...AT SOME POINT MON
MORNING/EARLY AFTN...THE SHARP SFC TROF/MESO LOW WILL BE PUSHED
ONSHORE. GIVEN THE UNCERTAINTY ON THE MESOSCALE DETAILS...WILL
CONTINUE TO HIGHLIGHT ERN ALGER/NRN LUCE CLOSE THE LAKE FOR GREATEST
ACCUMULATIONS TONIGHT/MON WITH POSSIBLE LOCALIZED 6-11 INCH AMOUNTS.
IF SOMETHING SETS UP AND REMAINS STATIONARY...COULD EASILY SEE OVER
A FOOT OF SNOW. OVER THE W...BITTER COLD ARCTIC AIR IS MORE LIKELY
TO ELIMINATE DGZ ALTOGETHER...RESULTING IN VERY SMALL SNOWFLAKES AND
LIMITING SNOW ACCUMULATIONS TO PROBABLY NOTHING MORE THAN 1-2 TO
PERHAPS 3 INCHES PER 12HR PERIOD. LOCALIZED ACCUMULATIONS OF MAYBE
4-5 INCHES WILL BE POSSIBLE IN THE EXPECTED CONVERGENCE ZONE IN
ONTONAGON COUNTY. RATHER THAN SNOW ACCUMULATIONS...THE BIGGER
CONCERN WILL BE VERY LOW VIS AS THE SMALL SNOWFLAKES WILL BE
EXTREMELY EFFECTIVE AT REDUCING VISIBILITY. MAY END UP WITH VERY LOW
VIS/NEAR WHITE-OUT CONDITIONS WHENEVER SNOW SHOWERS PASS DUE TO THE
CONSIDERABLE AMOUNT OF FINE SNOWFLAKES IN THE AIR. THIS TYPE OF FINE
SNOW IS ALSO VERY EASILY BLOWN ABOUT BY VEHICLES...SO VIS ON ROADS
WILL BE ESPECIALLY LOW IN THE VCNTY OF OTHER VEHICLES...MAKING
TRAVEL DANGEROUS DESPITE THE LACK OF SIGNIFICANT SNOW ACCUMULATIONS.
CONSIDERING VIS IMPACTS RATHER THAN SNOW IMPACTS...WILL BE ISSUING A
WINTER WX ADVY FOR ONTONAGON/HOUGHTON/KEWEENAW THRU TUE MORNING TO
HIGHLIGHT VERY POOR VIS IN SHSN AND ALSO TO COVER WIND CHILLS WHICH
WILL BE FALLING TO AROUND THE WIND CHILL ADVY CRITERIA OF -25F.
OTHER CONCERN TONIGHT/MON WILL BE THE BITTER COLD AIR. POOL OF SUB
-30C AIR AT 850MB ADVECTING INTO THE UPPER LAKES MON SUGGESTS MOST
OF THE W HALF OF UPPER MI AWAY FROM IMMEDIATE LAKE SUPERIOR
INFLUENCE WILL STAY BLO ZERO DURING THE DAY MON. IN FACT...IT MAY BE
A STRUGGLE TO RISE MUCH ABOVE -10F ACROSS GOGEBIC COUNTY WHERE LAKE
MODERATION WILL BE LEAST. OTHERWISE...SINGLE DIGITS BLO ZERO SHOULD
BE THE RULE FOR HIGHS OVER THE W MON. WHILE IT`S OFTEN TOUGH TO KEEP
WINDS AOA THE 10MPH THRESHOLD AT NIGHT...CAA MAY BE ENOUGH TO KEEP
WINDS UP SUFFICIENTLY TO SATISFY WIND CHILL CRITERIA LATER TONIGHT.
HAVE EXPANDED WIND CHILL ADVY TO COVER ROUGHLY THE W HALF OF UPPER
MI OUTSIDE OF AFOREMENTIONED WINTER WX ADVY AREA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
AGREEMENT REMAINS GOOD IN THE LARGE SCALE PATTERN FOR THE UPCOMING
WEEK. MODELS ARE NOW EVEN IN OKAY AGREEMENT IN THEIR HANDLING OF
BREAKING DOWN THE DEEP TROUGH OVER THE AREA TO START THE WEEK AND
RESULTING SFC LOW MOVING FROM CENTRAL PLAINS ACROSS THE OHIO VALLEY
THURSDAY INTO FRIDAY.
BY LATE MONDAY GRIP OF COLD WILL BE IN FULL FORCE WITH H85 TEMPS
NEAR -30C OVER FAR WEST AND H95 TEMPS BLO -20C. NO REAL CHANGE TO
EXPECTED MSLP PATTERN WITH LAKE INDUCED TROUGHING AS FAR NORTH AS
EASTERN LK SUPERIOR WHILE HIGH PRESSURE IS CENTERED FROM SOUTHERN
SASKATCHEWAN INTO SOUTHERN MN AND IOWA. RESULT IS PERSISTENT
UNIDIRECTIONAL NW FLOW SFC-H5 ALLOWING LK EFFECT TO CONTINUE. AS IT
HAS APPEARED LAST COUPLE DAYS...MOST CONCENTRATED AND HEAVIEST LK
EFFECT WILL BE OVER FAR NORTHEAST CWA ALONG LK SUPERIOR...EAST OF
MUNISING TO NORTH OF SENEY AND NEWBERRY. AVAILABLE HIGHER RESOLUTION
MODELS STILL PEGGING QPF AMOUNTS OVER 0.20 INCH/12 HR FOR MON NIGHT
AND TUESDAY AND TUESDAY NIGHT. NO DOUBT CONVERGENCE WILL BE
MAXIMIZED DUE TO LARGE SCALE LAKE INDUCED TROUGHING AND ASSOCIATED
MESOLOW FORMING OVER SOUTHEAST LK SUPERIOR DUE TO LAND BREEZES OFF
UPR MICHIGAN AND ONTARIO. AS ALLUDED TO IN SHORT TERM DISCUSSION...
EXACTLY WHERE HEAVIER SNOW BANDS TIED TO THIS MESOSCALE FEATURE SET
UP IS HARD TO PIN DOWN.
MAIN ADJUSTMENT TO QPF/SNOW WAS TO KEEP HIGHER AMOUNTS CLOSER TO
SHORE THAN WHAT MODELS SHOW AS USUALLY LAND BREEZE DOMINATED
CONVERGENCE ZONE ENDS UP CLOSER TO THE LAKE THAN MODELS PORTRAY.
GIVEN THE VERY COLD AIRMASS...SLR/S WILL BE LESS THAN 15:1. OUTSIDE
OF AREAS WHERE STRONGEST CONVERGENCE/MOISTURE FLUXES OCCUR SLR/S
PROBABLY END UP MORE TOWARD 10:1 AS VERY FINE SNOWFLAKES DOMINATE.
SNOW AMOUNTS LIKELY END UP 3-5 INCHES EVERY 12 HRS UNDER DOMINATE
BAND IN THE EAST...BUT FOR REST OF AREAS FAVORED BY NW FLOW ALONG LK
SUPERIOR EXPECT JUST A FEW INCHES EVERY 12 HRS. DUE TO MODERATE SNOW
AMOUNTS SNOW AND POOR VSBY ALONG WITH POSSIBILITY OF DOMINATE BAND
ENHANCING SNOW AMOUNTS...COORD WITH SHORT TERM FORECASTER AND
EXTENDED LK EFFECT SNOW WARNING FOR EASTERN AREAS THROUGH 12Z
TUESDAY. FOR MOST LOCATIONS NEAR LK SUPERIOR IT WILL BE THE POOR VSBY
INSTEAD OF THE SNOW AMOUNTS THAT WILL BE THE HIGHER IMPACT ISSUE.
FREQUENT WHITEOUT CONDITIONS ARE EXPECTED AS THE SMALL SNOW FLAKES
FALLING WITH EVEN 10-20 MPH WINDS WILL BE VERY PROFICIENT IN LEADING
TO LOWER VSBY.
BITTER COLD WIND CHILLS ARE THE OTHER ISSUE EARLY THIS WEEK. AS IT
APPEARED YDY...TIGHTEST PRESSURE GRADIENT IS PRESENT TO BEGIN THE
LONG TERM BUT IT GRADUALLY RELAXES BY TUESDAY MORNING AND EVEN
FURTHER BY WEDNESDAY MORNING. EXPECT MIN TEMPS MONDAY NIGHT TO FALL
LESS THAN 10 BLO OVER A MAJORITY OF WEST HALF OF UPR MICHIGAN WITH
WIND CHILL READINGS DOWN TO 25-30 BLO ZERO. POSSIBLE THAT WINDS MAY
NOT TECHNICALLY REACH CRITERIA /SUSTAINED AT 10 MPH/ BUT IT IS
CERTAINLY CLOSE ENOUGH TO ISSUE A HEADLINE. AFTER COORD WITH SHORT
TERM FORECASTER...DECIDED TO ISSUE CATCH ALL WINTER WEATHER ADVY
OVER WESTERN TIER OF CWA FOR LK EFFECT SNOW/POOR VSBY AND THE BITTER
COLD WIND CHILLS. THIS HEADLINE WILL RUN THROUGH MIDDAY TUESDAY.
ELSEWHERE OVER WEST HALF OF UPR MICHIGAN...GOING TO ISSUE WIND CHILL
ADVY THROUGH MIDDAY TUESDAY. FURTHER REFINEMENTS MAY BE NEEDED TO
HEADLINES AS WE GET INTO MONDAY/TUESDAY...BUT THIS WILL BE OUR
STARTING POINT.
WORKING INTO TUESDAY NIGHT AND WEDNESDAY CONDITIONS CHANGE A BIT.
MAIN CHANGE IS BLYR WINDS BACKING MORE WSW TUESDAY NIGHT AND H925
WINDS BACKING WESTERLY. CHANGE IN WIND WILL PUSH ONGOING LK EFFECT
AND CLOUDS OVER THE WEST FARTHER TO THE NORTH. LK EFFECT STAYS IN
PLACE MOSTLY OVER THE EAST...STILL FALLING MODERATE AT TIMES...AS
THE STATIONARY MESOLOW REMAINS PRIMARY FEATURE DRIVING THE SNOW
THERE. THINKING THAT WITH WEAK PRESSURE GRADIENT AND LOSS OF CLOUDS
SHOULD ALLOW FOR WINDS OVER INTERIOR TO BECOME CALM AND PRIME
RADIATIONAL COOLING TO DEVELOP. LOWERED MIN TEMPS TOWARD LOWEST
GUIDANCE NUMBERS AROUND 20 BLO ZERO. MAY EVEN SEE LOWER TEMPS AT THE
FAVORED COLD SPOTS...BUT WILL JUST TREND IN THE COLDER DIRECTION FOR
NOW. ONLY CONCERN IN MIN TEMP FCST IS POSSIBLE INCREASING CLOUDS
ALOFT AHEAD OF ANOTHER TROUGH THAT DROPS IN ON WEDNESDAY. THINK
THOSE MID CLOUDS WILL HOLD OFF LONG ENOUGH TO ALLOW TEMPS TO TANK ON
TUESDAY NIGHT.
AS UPPER TROUGH BEGINS TO LOSE GRIP OVER AREA ON WEDNESDAY...MODELS
SHOWING SHORTWAVE DIPPING FROM NORTHERN PLAINS ON WEDNESDAY NIGHT TO
ACROSS LOWER GREAT LAKES LATER THURSDAY. MAJORITY OF SYNOPTIC SNOW
FROM THE SYSTEM PROBABLY MISSES UPR MICHIGAN...PERHAPS JUST TO THE
SOUTH THOUGH ACROSS WI AND LOWER MICHIGAN. INDICATION IS THAT FLOW
WILL BE SPLIT AND THE SOUTHERN SHORTWAVE DRIVES THE MAIN SYSTEM TO
THE SOUTH...BUT THERE IS ALSO NORTHERN STREAM WAVE DROPPING ACROSS
UPR LAKES THURSDAY NIGHT INTO FRIDAY. THIS MAY KEEP AN INVERTED SFC
TROUGH WELL TO NORTHWEST OF MAIN SFC LOW WHICH COULD LEAD TO SCT
SNOW SHOWERS OVR UPR LAKES ENHANCED FURTHER BY ONSHORE FLOW OFF LK
SUPERIOR. CONSENSUS POPS LOOKED OKAY...BUT DID INCREASE THEM
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT NEAR LK SUPERIOR. BASED ON
MSLP AND H85 RH/TEMPS...LK EFFECT CONTINUES THROUGH FRIDAY AND
EVEN INTO SATURDAY OVER THE EASTERN CWA...THOUGH INCREASING LOW-MID
LEVEL RIDGING WILL LEAD TO INCREASINGLY HOSTILE CONDITIONS FOR THE
LK EFFECT.
HEIGHTS FURTHER FLATTEN OUT THROUGH NEXT WEEKEND LEADING TO WARMER
AIR SPILLING ACROSS NORTHERN PLAINS AND UPR LAKES. COULD BE WARM AIR
ADVECTION TYPE SYSTEM SNOW BUT GFS AND ECMWF DIFFER ON TRACK OF
SHORTWAVE AND SFC TROUGH TO ENHANCE THAT SNOW POTENTIAL /ECMWF
FARTHER NORTH WHILE GFS MOVES FOCUS ACROSS UPR MICHIGAN/ SO WILL NOT
ALTER THE SLIGHT CHANCES THAT CONSENSUS GAVE FOR POPS. AFTER A
BITTER COLD START TO THE WEEK...APPEARS THAT TEMPS TO END THE WEEK
INTO NEXT WEEKEND WILL SHOW WARMING TREND WITH READINGS CLOSE TO
NORMAL BY NEXT SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1233 AM EST MON JAN 21 2013
KIWD...WSW FLOW WILL VEER WNW LATE TONIGHT AND SHOULD BRING SOME
MVFR CIGS IN LIGHT LAKE EFFECT SNOW. SOME GUSTIER WINDS MONDAY
SHOULD CONTRIBUTE TO IFR CONDITIONS BY LATE MORNING WHICH WILL
LIKELY PERSIST INTO THE EVENING.
KCMX...LAKE EFFECT SNOW SHOWERS WITH FINE SNOWFLAKES WILL CONTRIBUTE
TO BLOWING SNOW AND SHARPLY REDUCED VSBYS THROUGH THE TAF PD WITH
PREVAILING LIFR CONDITIONS.
KSAW...WEST FLOW VEERING NORTHWEST ON MONDAY MORNING WILL ALLOW VFR
CONDITIONS TO TURN TO MVFR AS SOME LAKE CLOUDS AND OCCASIONAL
FLURRIES MOVE INTO THE AREA. VSBY COULD EVEN OCCASIONALLY LOWER TO
MVFR IN LIGHT -SHSN DURING THE DAY ON MONDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 PM EST SUN JAN 20 2013
NW WINDS OF 15-30KT WILL DOMINATE LAKE SUPERIOR TONIGHT THRU MON AS
INCREASINGLY COLDER ARCTIC AIR FLOWS OVER THE LAKE. ONLY EXCEPTION
WILL BE OVER THE FAR E WHERE LAND BREEZES OFF UPPER MI AND ONTARIO
MAY YIELD A SHARP SFC TROF OR MESOLOW. AS A RESULT...WINDS MAY SHIFT
TO A LIGHTER OFFSHORE DIRECTION EAST OF GRAND MARAIS TONIGHT WHILE
LAND BREEZE E TO NE WINDS PUSH OVER THE LAKE FROM ONTARIO INTO THE
AREA S OF CARIBOU ISLAND. SFC TROF/MESO LOW WILL MOVE S OR SE MON...
BRINGING STRONGER N OR NW WINDS BACK TO THAT AREA. HVY FREEZING
SPRAY WILL CONTINUE UNDER BITTER COLD AIR FLOWING INTO THE AREA.
EXPECT WINDS TO STAY IN THE 20 TO 30 KT RANGE THROUGH MIDDLE OF WEEK
THEN WINDS FINALLY RELAX AS HIGH PRESSURE BEGINS TO BUILD ACROSS REGION.
HEAVY FREEZING SPRAY WILL SUBSIDE...BUT NOT UNTIL WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ004-
005-009>011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS
MARINE...ROLFSON/JLA
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1135 PM CST SUN JAN 20 2013
.AVIATION...
FOR THE 06Z TAFS...STILL REMAINS A LOW CONFIDENCE FORECAST THROUGH
12Z WITH REGARDS TO THE POTENTIAL OF FG AND LOW STRATUS. FOR
NOW...IT LOOKS LIKE THE RISK AT ANY OF THE TAF SITES IS RATHER LOW.
THERE IS ONE PATCH OF LOW STRATUS WITH CEILINGS AROUND OVC015 IN SW
KS. HOWEVER...SO FAR THIS DECK DOES NOT SEEM TO BE EXPANDING...AND IN
FACT DEW POINTS UPSTREAM ARE CONSIDERABLY LOWER THAN WHAT IS
CURRENTLY OBSERVED AT THE TAF SITES. IT IS POSSIBLE AS THIS DECK
ADVECTS SW...THAT IT COULD MOVE OVER EITHER KGUY OR KDHT...BUT MORE
LIKELY THE DECK WILL REMAIN NW OF THOSE SITES. AT KAMA...THE CONCERN
IS BR OR FZFG...BUT WITH THE LOWER DEW POINTS UPSTREAM...WINDS
REMAINING N INSTEAD OF NE...AND ONLY A BRIEF WINDOW WHERE DEW POINT
DEPRESSIONS COULD BE BELOW 5F...THIS SEEMS ALSO UNLIKELY.
ANY LOW STRATUS OR FG SHOULD DISSIPATE QUICKLY AFTER SUNRISE LEAVING
CLEAR SKIES AND WINDS GRADUALLY SHIFTING TO SW.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 934 PM CST SUN JAN 20 2013/
UPDATE...
WITH EACH SUBSEQUENT MODEL RUN...THE PROSPECTS FOR PATCHY FREEZING
FOG APPEAR TO BE A BIT LOWER...ESPECIALLY IN THE WESTERN HALF OF THE
PANHANDLES. CONSENSUS FCST SOUNDINGS AND MOS FAVOR EITHER LOW CLOUDS
OR NOTHING AT ALL FROM ROUGHLY AMARILLO TO GUYMON WESTWARD. EAST OF
THIS LINE...FREEZING FOG...THOUGH STILL VERY QUESTIONABLE...LOOKS A
BIT MORE LIKELY GIVEN CURRENT DEWPTS NEAR 30F AND EXPECTED LOWS IN
THE HIGH TEENS TO MID 20S. HOWEVER...SLIGHTLY STRONGER GRADIENT WINDS
AND THE POTENTIAL FOR LOW STRATUS TO MOVE IN FIRST COULD PRECLUDE
FREEZING FOG HERE AS WELL.
ALL IN ALL...WILL LEAVE THE INHERITED PATCHY FREEZING FOG MENTION IN
EVERYWHERE FOR LATE TONIGHT AND TOMORROW MORNING...AS IT IS JUST TOO
HARD TO IGNORE THE CURRENT ELEVATED DEWPTS AND CLIMATOLOGICALLY
FAVORABLE SETUP. THINK THE BEST CHANCE FOR FREEZING FOG WILL BE IN
THE PERRYTON/MIAMI/CANADIAN/BEAVER/LIPSCOMB AREAS...THOUGH PATCHY
FREEZING FOG CANNOT BE RULED OUT FOR EVERYONE.
SIMPSON
PREV DISCUSSION... /ISSUED 535 PM CST SUN JAN 20 2013/
AVIATION...
FOR THE 00Z TAFS...VFR CONDITIONS SHOULD CONTINUE THROUGH 06Z. AFTER
06Z...FORECAST CONFIDENCE DECREASES. THERE WILL BE SOME MOISTURE
POOLING BEHIND THE COLD FRONT WHICH MOVED THROUGH EARLIER. DEPENDING
ON HOW MUCH...THIS COULD LEAD TO THE DEVELOPMENT OF LOW CLOUDS AND
FZFG BETWEEN 06 AND 15Z. HOWEVER...LATEST MODELS HAVE TRENDED DOWN
WITH THE AMOUNT OF MOISTURE AVAILABLE...SO HAVE ONLY MENTIONED A SCT
DECK AND MVFR VISIBILITIES FOR NOW.
JOHNSON
PREV DISCUSSION... /ISSUED 310 PM CST SUN JAN 20 2013/
DISCUSSION...
THROUGH TONIGHT: MAIN CONCERN TONIGHT REVOLVES AROUND POTENTIAL
DEVELOPMENT OF FREEZING FOG VS. LOW STRATUS. A DRY COLD FRONT
LOCATED ALONG THE CANADIAN RIVER VALLEY IS TRUCKING SOUTHWARD THIS
AFTERNOON. STRONG NORTHERLY WINDS HAVE DEVELOPED BEHIND THE FRONT
WITH A FEW GUSTS UP TO 35 MPH. THIS NORTHERLY SURGE OF GUSTY WINDS
WILL CONTINUE TO PUSH SOUTHWARD THROUGH THE AFTERNOON AND EVENING
HOURS, BUT IT SHOULD DIMINISH IN INTENSITY NEAR SUNSET. LOW-LEVEL
MOISTURE IS EXPECTED TO POOL BEHIND THE FRONT TONIGHT, BUT MODEL
GUIDANCE SHOWS VARYING DEGREES OF MOISTURE CONTENT. THE LATEST RUC
AND HRRR HAVE BACKED OFF ON THE POTENTIAL FOR WIDESPREAD FREEZING
FOG, BUT THE GFS AND NAM CONTINUE TO INDICATE THIS POTENTIAL. GIVEN
THE SYNOPTIC PATTERN, THIS SETUP IS LOCALLY FAVORABLE FOR SOME
PATCHY (FREEZING) FOG, SO WE LEFT THIS IN THE FORECAST. WE EXPECT
FREEZING FOG TO DEVELOP BETWEEN 3 AM ACROSS THE EASTERN PANHANDLES
AND SPREAD WESTWARD. OTHER MODEL GUIDANCE, INCLUDING THE TEXAS TECH
WRF, INDICATES THAT LOW STRATUS WILL BE MORE FAVORED THAN FOG. DUE
TO THESE UNCERTAINTIES, WE INCLUDED BOTH INCREASING CLOUDS AND PATCHY
FREEZING FOG IN THE FORECAST, BUT OUR FORECAST CONFIDENCE IS LOW.
OVERNIGHT LOW TEMPERATURES WILL RANGE FROM THE UPPER TEENS TO UPPER
20S. THE POTENTIAL FOR FREEZING DRIZZLE THAT WE DISCUSSED YESTERDAY
HAS DIMINISHED AS THE DEPTH OF THE MOIST LAYER WILL BE LESS THAN
2000 FEET.
MARTIN LUTHER KING, JR. DAY-NIGHT: ANY FREEZING FOG THAT DEVELOPS
OVERNIGHT SHOULD DISSIPATE BY 10 AM. LOW CLOUDS, IF THEY DEVELOP,
COULD HANG TOUGH INTO THE EARLY AFTERNOON HOURS, ESPECIALLY ACROSS
THE SOUTHEASTERN TEXAS PANHANDLE. SURFACE WINDS WILL QUICKLY SHIFT TO
THE SOUTH BY THE AFTERNOON HOURS, BUT HIGH TEMPERATURES WILL BE ABOUT
10-15 DEGREES COLDER THAN TODAY DUE TO THE MODIFIED ARCTIC AIR MASS.
TUESDAY-SUNDAY: A BACKDOOR COLD FRONT WILL SNEAK INTO THE
NORTHEASTERN HALF OF THE FORECAST AREA TUESDAY MORNING AND MAY BE
SLOW TO RETREAT NORTHWARD. THIS SHOULD KEEP AN UPSLOPE COMPONENT TO
THE WINDS FOR MUCH OF THE DAY. AS A RESULT, WE COOLED HIGHS OFF
SEVERAL DEGREES, AND THERE IS A POSSIBILITY WE MAY STILL BE TOO WARM.
THIS FRONT WILL LIFT OUT OF THE FORECAST AREA ON WEDNESDAY AS UPPER
RIDGING BUILDS ACROSS THE AREA. HIGHS ON WEDNESDAY ARE EXPECTED TO
WARM INTO THE LOWER 60S TO POSSIBLY NEAR 70. AN UPPER TROUGH MOVING
INTO NORTHERN PLAINS ON THURSDAY WILL SWING ANOTHER DRY COLD FRONT
SOUTHWARD. WE SPED UP THE TIMING OF THE FRONT GIVEN THAT IT WILL ALSO
BE A STRONG FRONT. AS A RESULT, HIGHS FOR THURSDAY HAVE BEEN TRIMMED
DOWNWARD AND WIND SPEEDS INCREASED, ESPECIALLY BEHIND THE FRONT.
COOLER TEMPERATURES WILL RETURN FOR FRIDAY, BUT A WARMING TREND WILL
RESUME FOR NEXT WEEKEND.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
MONDAY THROUGH WEDNESDAY AS RELATIVE HUMIDITY VALUES WILL REMAIN
ABOVE 20 PERCENT AND/OR 20-FOOT WINDS WILL REMAIN BELOW 15 MPH.
ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS THE WESTERN
TWO THIRDS OF THE PANHANDLES ON THURSDAY AS DRY NORTHERLY WINDS
INCREASE. ELEVATED FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE
ACROSS THE FAR WESTERN PANHANDLES ON SATURDAY.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
16/09
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
306 AM CST MON JAN 21 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
306 AM CST MON JAN 21 2013
THE CONTINUED FOCUS REMAINS ON THE BITTERLY COLD AIR MASS THAT HAS
HUNKERED DOWN ACROSS THE REGION AND WILL LINGER THROUGH THE NEXT
FEW DAYS.
BROAD CYCLONIC FLOW ALOFT REMAINS ENTRENCHED ACROSS THE REGION AS
THE POLAR VORTEX HAS DRIFTED INTO SOUTHEAST CANADA. AS SHORT WAVE
TROUGHS HAVE PROPAGATED ALONG THE WESTERN PERIPHERY OF THIS
TROUGH...THEY HAVE BROUGHT REINFORCING SHOTS OF COLD AIR ON DOWN
WITH THEM. THE LATEST SHORT WAVE CAME THROUGH EARLY THIS MORNING
AS NOTED ON WATER VAPOR IR. AHEAD OF THIS TROUGH...A COLD FRONT
ALSO MOVED INTO THE REGION WHICH BROUGHT SOME FLURRIES AND SNOW
SHOWERS IN AS WELL. BEHIND THIS FRONT...SKIES CLEAR OUT AND
TEMPERATURES DROP BELOW ZERO. A STRENGTHENING PRESSURE GRADIENT
ALSO HELPED TO INCREASE THE SURFACE WINDS AND TO DROP WIND CHILLS
DOWN INTO THE ADVISORY LEVELS. AS THIS COLDER AIR MASS SHIFTS TO
THE SOUTHEAST THIS MORNING THESE LOWER WIND CHILLS WILL ALSO START
TO OCCUR AT SITES IN NORTHEAST IOWA AND WESTERN WISCONSIN THAT
HAVE BEEN IN THE -5 TO -15F RANGE SO FAR.
HAD THERE BEEN ANY SNOW COVER ON THE GROUND...TEMPERATURES
PROBABLY WOULD NOT MAKE IT ABOVE ZERO TODAY. FORTUNATELY...THE
SNOW PACK MELTED AWAY LAST WEEK AND THE LATEST NOHRSC SNOW DEPTH
ANALYSIS AND LOCAL COOP OBSERVERS SHOWS MOSTLY ZERO SNOW COVER
OUTSIDE OF A FEW SPORADIC 1-3 INCH REPORTS. EVEN WITHOUT THE SNOW
COVER...TEMPERATURES ARE GOING TO REMAIN COLD AS THE CORE OF THE
COLD AIR MASS DROPS DOWN ACROSS THE REGION. 850MB TEMPERATURES
WILL STICK AROUND -25C FOR MOST OF THE AREA WITH THE COLDEST
POCKET OF AIR RUNNING FROM NORTHEAST MINNESOTA INTO NORTH CENTRAL
WISCONSIN. WIND CHILLS SHOULD STAY NEAR OR BELOW -20F THROUGH THE
DAY...SO WILL NOT MAKE ANY CHANGES TO THE WIND CHILL ADVISORY.
21.06Z RAP SOUNDINGS SHOW THAT THERE COULD BE SOME CU THAT FORMS
EAST OF THE RIVER TODAY...SO CAN NOT RULE OUT SOME FLURRIES THERE
AS WELL. BASICALLY...IF WE GET ANY LOW LEVEL CLOUD COVER OVER THE
NEXT FEW DAYS...THERE WILL LIKELY BE SOME FLURRIES OR SNOW SHOWERS
THAT ACCOMPANY IT WITH THE LOW LEVEL TEMPERATURE PROFILE BELOW
-20C. AT THESE TEMPERATURES...WOULD MAINLY EXPECT THE SNOWFLAKES
TO BE PLATES AND COLUMNS AND NOT AMASS TO MUCH IF ANYTHING.
TEMPERATURES WILL START TO IMPROVE ON TUESDAY AS THE BROAD UPPER
TROUGH SHIFTS EAST AND THE CORE OF THE SURFACE RIDGE MOVES ACROSS
THE REGION WITH LOW LEVEL WINDS COMING AROUND TO THE SOUTHWEST.
WILL HAVE TO KEEP AN EYE ON TUESDAY NIGHT INTO WEDNESDAY FOR THE
POTENTIAL OF SOME WARM AIR ADVECTION SNOW. THE 21.00Z NAM IS A BIT
STRONGER WITH THE LOW LEVEL LIFT AND SATURATION COMPARED TO THE
REST OF THE GUIDANCE. HAVE KEPT JUST FLURRIES IN THE FORECAST FOR
NOW...BUT MAY NEED TO RAMP THINGS UP IF THE FORCING DOES LOOK
LEGIT.
.LONG TERM...THURSDAY THROUGH SUNDAY
306 AM CST MON JAN 21 2013
GOING INTO THE LATER PORTION OF THE WEEK ON INTO THE WEEKEND...THE
MAIN FOCUS IS ON A SYSTEM THAT WILL DROP OUT OF SOUTH CENTRAL
CANADA THURSDAY INTO FRIDAY AND BRING THE NEXT BEST CHANCE FOR AN
ACCUMULATING SNOW WITH IT. TRENDS HAVE WAVERED BACK AND FORTH ON
THE TIMING OF WHEN THIS FEATURE MOVES IN WITH THE 21.00Z GFS/ECMWF
SLOWING IT DOWN A TAD WITH MUCH OF THE SNOW FALLING THURSDAY
AFTERNOON INTO FRIDAY MORNING. 21.00Z GFS BUFKIT SOUNDINGS FOR
THIS EVENT SHOW A FAIRLY DEEP DENDRITIC GROWTH ZONE WITH FORCING
THROUGH THIS LAYER WHICH COULD LEAD TO SOME HIGH SNOW RATIOS.
DETAILS WILL NEED TO BE WORKED OUT ON THIS SYSTEM...BUT IT LOOKS
LIKE THE POTENTIAL IS THERE FOR AN ACCUMULATING SNOW...WITH THE
BETTER CHANCES FOR ACCUMULATIONS IN CENTRAL WISCONSIN.
TEMPERATURE-WISE...WE ARE STILL IN NORTHWEST FLOW ALOFT...SO THE
COOL AIR WILL REMAIN IN PLACE THOUGH NEXT WEEKEND WITH
TEMPERATURES LINGERING MAINLY JUST BELOW NORMAL.
&&
.AVIATION...THROUGH 06Z TUESDAY
1125 PM CST SUN JAN 20 2013
PRESSURE GRADIENT HAS TIGHTENED THIS EVENING AS WEST TO NORTHWEST
WINDS NOW GUSTING TO 20 TO 25 KNOTS AT BOTH SITES. THIS TREND WILL
CONTINUE THROUGH THE NIGHT AND EVEN INTO MONDAY. SHOULD BEGIN TO
SEE A DECREASE AFTER 00Z TUESDAY...BUT STILL IN THE 10 TO 13 KNOT
RANGE. EXPECT ANY MVFR CEILINGS AND FLURRIES TO PUSH OUT OF THE
TAF SITES BY 09Z...WITH VFR CONDITIONS THEN EXPECTED AFTER THAT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CST MON JAN 21 2013
WI...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1125 PM CST SUN JAN 20 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
250 PM CST SUN JAN 20 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES/WIND CHILLS THROUGH
TUESDAY AND ANY POTENTIAL LIGHT PRECIPITATION THROUGHOUT THE SHORT
TERM.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE U.S. WEST COAST INTO WESTERN BRITISH
COLUMBIA...WHILE DEEP TROUGHING ENCOMPASSED THE EASTERN TWO-THIRDS
OF CANADA INTO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES
REGIONS. 500MB HEIGHTS AS WELL AS 850MB TEMPS WERE 1-1.5 STANDARD
DEVIATIONS BELOW NORMAL OVER THE FORECAST AREA. REGARDING THE 850MB
TEMPS...RAP ANALYSIS SHOWED READINGS OF -16 TO -20C OVER THE
FORECAST AREA. WITHIN THE DEEP TROUGHING...A SHORTWAVE WAS EVIDENT
FROM EASTERN SOUTH DAKOTA INTO NORTHERN IOWA. DPVA ASSOCIATED WITH
THE SHORTWAVE...MID-LEVEL MOISTURE SEEN ON THE 12Z ABR SOUNDING...AS
WELL AS LOW TO MID LEVEL FRONTOGENESIS WAS SUPPORTING AN AREA OF
LIGHT SNOW JUST SOUTH OF THE SHORTWAVE ACROSS WESTERN AND CENTRAL
IOWA. ONLY SOME SCATTERED ALTOSTRATUS HAS OVERSPREAD THE FORECAST
AREA ASSOCIATED WITH THE SHORTWAVE. SUNSHINE THROUGH THESE CLOUDS
AND THE COLD 850MB TEMPS HAS ONLY ALLOWED TEMPERATURES TO CLIMB INTO
THE LOWER TO MID TEENS. ON THE WEST SIDE OF THE DEEP TROUGH...A
120-140 KT JET AT THE TROPOPAUSE WAS DROPPING DOWN THROUGH EASTERN
ALBERTA AND SASKATCHEWAN. THE STRENGTH OF THIS JET IS PARTLY DUE TO
ANOTHER SURGE OF ARCTIC AIR...WITH THE RAP SHOWING 850MB TEMPS OF
-25 TO -30C FROM NORTH DAKOTA INTO MANITOBA. THIS COLD AIR WAS ALSO
SITTING RIGHT BEHIND A COLD FRONT STRETCHING FROM NEAR ABERDEEN
SOUTH DAKOTA INTO THE MN ARROWHEAD.
TONIGHT AND MONDAY...THE 120-140 KT JET STREAK OVER EASTERN ALBERTA
INTO SASKATCHEWAN IS PROGGED TO DIG INTO THE DAKOTAS TONIGHT AND INTO
IOWA ON MONDAY. THE FORECAST AREA ENDS UP IN THE LEFT EXIT REGION OF
THIS JET MONDAY MORNING...WHILE THE TROPOPAUSE DROPS TO AROUND
375MB. THESE STRENGTHENING UPPER DYNAMICS WILL END UP TIGHTENING THE
SURFACE PRESSURE GRADIENT OVER THE FORECAST AREA TONIGHT...HELPING
TO BRING IN THAT VERY COLD 850MB AIR ACROSS NORTH DAKOTA. NOT
ANTICIPATING ANY PRECIPITATION FROM THE DYNAMICAL FORCING...
PRIMARILY BECAUSE THERE IS TOO MUCH MID-LEVEL DRY AIR ACCOMPANYING
THE COLD ADVECTION AS SHOWN ON FORECAST SOUNDINGS. IN ADDITION...
THERE ARE CLEAR SKIES CURRENTLY PRESENT OVER NORTHWEST NORTH DAKOTA
AND SOUTH CENTRAL CANADA IN THE LEFT EXIT REGION. ONLY PRECIPITATION
THAT MAY OCCUR WOULD BE LIMITED TO FLURRIES...ASSOCIATED WITH THE
LOW CLOUDS AHEAD OF THAT COLD FRONT DROPPING SOUTHEAST OUT OF
NORTHERN SOUTH DAKOTA INTO THE MN ARROWHEAD. ADDITIONAL FLURRIES
COULD OCCUR ON MONDAY NORTH OF I-94...ASSOCIATED WITH LOW TO MID
LEVEL MOISTURE MOVING THROUGH WHICH IS CURRENTLY IN NORTHERN
MANITOBA. REGARDING TEMPERATURES...THEY ARE TRICKY GIVEN THE LACK OF
SNOW COVER AND THE INCREASING WINDS PROMOTING MIXING. WE DEFINITELY
ARE NOT GOING TO GET AS COLD AS THE DAKOTAS AND NORTHERN MN WHERE
SNOW EXISTS. STILL...ADVECTION ALONE AND CLEARING SKIES...COMBINED
WITH THE FACT THAT THE INCOMING 850MB TEMPS ARE 2-2.5 STANDARD
DEVIATIONS BELOW NORMAL...SHOULD ALLOW TEMPERATURES IN MOST
LOCATIONS TO DROP BELOW ZERO. SOME LOCATIONS OVER NORTH CENTRAL
WISCONSIN AND SOUTHEAST MN COULD EVEN DROP TO 10 BELOW ZERO OR SO.
TEMPERATURES WILL STRUGGLE TO RECOVER ON MONDAY BEING UNDER THE
850MB THERMAL TROUGH...BUT SUN AND BARE GROUND SHOULD GET HIGHS TO
NEAR OR SLIGHTLY ABOVE ZERO PER THE ECMWF. THE ECMWF HAS DONE WELL
HANDLING HIGH TEMPERATURES WITH THE BARE GROUND AND THUS WAS THE
PREFERRED GUIDANCE. WIND CHILLS WILL SOLIDLY END UP IN THE WIND
CHILL ADVISORY RANGE FROM LATE TONIGHT INTO MUCH OF MONDAY... AND
MAY EVEN APPROACH WARNING MONDAY MORNING OVER PORTIONS OF SOUTHEAST
MN. CONFIDENCE IS STILL NOT HIGH ENOUGH TO GO WITH THE WARNING GIVEN
UNCERTAINTY ON LOW TEMPERATURES.
MONDAY NIGHT AND TUESDAY...THE DEEP UPPER TROUGH IS PROGGED TO SHIFT
SLIGHTLY EASTWARD DURING THIS PERIOD AS THE RIDGE ALONG THE U.S.
WEST COAST GETS A PUSH EAST. IN RESPONSE...THE ARCTIC HIGH PRESSURE
AREA CURRENTLY SITTING UP IN ALBERTA IS ALLOWED TO BUILD INTO THE
FORECAST AREA. MODELS ARE IN GOOD AGREEMENT OF THE HIGH PRESSURE
AREA ENCOMPASSING THE AREA AT 00Z WEDNESDAY. UNTIL THE HIGH BUILDS
IN...A SLOWLY WEAKENING PRESSURE GRADIENT WILL EXIST...MAINTAINING A
NORTHWESTERLY BREEZE AND KEEPING WIND CHILLS DOWN. THUS...HAVING THE
WIND CHILL ADVISORY GO TO 18Z TUESDAY STILL LOOKS GOOD. SKIES SHOULD
END UP CLEAR IN MOST AREAS BY 12Z TUESDAY...FAVORING GOOD
RADIATIONAL COOLING. AGAIN...THE LACK OF SNOW COVER AND BREEZE WILL
ACT AGAINST GETTING TOO COLD. GIVEN THE COLDER MONDAY COMPARED TO
TODAY...SHOULD SEE LOWS AT LEAST A FEW DEGREES COLDER...ESPECIALLY
OVER THE SNOWPACK NORTH OF HIGHWAY 10. 850MB AND 925MB TEMPERATURES
ARE PROGGED TO ONLY SLOWLY RECOVER...CLIMBING TO -18 TO -22C AND -16
TO -22C RESPECTIVELY BY 00Z. DESPITE PLENTY OF SUNSHINE MINUS SOME
INCREASING HIGH CLOUDS IN THE AFTERNOON...ONLY ANTICIPATING HIGHS 5
TO 10 DEGREES WARMER PER ECMWF.
TUESDAY NIGHT AND WEDNESDAY...MODELS PROG A POTENT SHORTWAVE TO DROP
SOUTH OUT OF NORTHERN MANITOBA LATE TUESDAY AND HAVE IT CROSS LAKE
SUPERIOR LATE WEDNESDAY. MEANWHILE...THE WESTERN UPPER RIDGE BREAKS
DOWN AND FLATTENS WHILE SPREADING EAST...IN RESPONSE TO A POTENT
SHORTWAVE TROUGH CROSSING THE PACIFIC NORTHWEST. THE RESULT OF ALL
THIS IS TO STRENGTHEN THE UPPER JET CORE AT THE TROPOPAUSE OVER OR
JUST NORTH OF THE FORECAST AREA...TOWARDS 150-170 KT. WITH THE
STRENGTHENING UPPER JET COMES AN ISENTROPIC LIFT AND LOW TO MID
LEVEL FRONTOGENESIS ZONE ON ITS SOUTHWEST SIDE. THIS RESULTS IN
INCREASING AND THICKENING MID AND HIGH CLOUDS OVER THE FORECAST
AREA. FORCING IS NOT ALL THAT STRONG PER MODEL DERIVED OMEGA
FIELDS...BUT THE LOW LEVELS DO SLOWLY SATURATE OVER TIME. THUS...
THINK FLURRIES AT A MINIMUM WILL OCCUR. 20.12Z NAM ACTUALLY PRODUCES
SOME LIGHT QPF...ALBEIT IS THE MOST DYNAMIC BY EVEN HAVING A SURFACE
LOW DROPPING THROUGH IOWA. FOR NOW JUST WENT WITH ADDING
FLURRIES...BUT SOME CHANCES OF PRECIPITATION MAY NEED TO BE ADDED IF
MODELS TREND TOWARDS THE NAM. WITH THE THICKENING CLOUD COVER
AND BARE GROUND...TEMPERATURES SHOULD NOT FALL ALL THAT MUCH TUESDAY
NIGHT. 925MB TEMPS WARM FURTHER ON WEDNESDAY WITH THE UPPER FLOW
TURNING MORE WEST-NORTHWESTERLY...CLIMBING TO -8C SOUTHWEST TO -16C
NORTHEAST BY 00Z. THUS...DESPITE CLOUD COVER...TEMPERATURES SHOULD
BE ABLE TO CLIMB INTO THE MID TEENS TO MID 20S.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
250 PM CST SUN JAN 20 2013
VERY GOOD AGREEMENT EXISTS ON THE LONG TERM PATTERN FROM THE 20.12Z
ECMWF/GFS/CANADIAN AND ECMWF ENSEMBLES. THE SHORTWAVE TROUGH OVER
THE PACIFIC NORTHWEST TO START THE PERIOD DIGS INTO NEBRASKA AND
IOWA FOR THURSDAY. AN INVERTED TROUGH ACCOMPANIES THE SHORTWAVE...
WITH A COMBINATION OF MID-LEVEL FRONTOGENESIS...DPVA AND MOISTURE
EXPECTING TO BRING SOME SNOW ACROSS THE FORECAST AREA. HOWEVER...
THIS HAS BEEN A POINT OF CONTENTION FOR A FEW DAYS...WITH MODELS
VARYING ON HOW MUCH QPF WITH EVEN A FEW SUGGESTING DRY EITHER ON
THURSDAY AND/OR THURSDAY NIGHT. AS SUCH...HAVE KEPT A CONSENSUS
AROUND 30 PERCENT CHANCE FOR BOTH THURSDAY AND THURSDAY NIGHT.
CERTAINLY IF THE TREND IN THE 20.12Z ECMWF CONTINUES...WE WILL NEED
HIGHER CHANCES AS IT NOW SUGGESTS UPWARDS OF 2-3 INCHES OF SNOW.
THIS IS QUITE A BIT DIFFERENT FROM ITS PREVIOUS RUN...THOUGH.
ANOTHER SURGE OF CANADIAN AIR WITH HIGH PRESSURE IS STILL FORECAST
TO DROP INTO THE FORECAST AREA IN THE WAKE OF THIS SYSTEM FOR FRIDAY
AND FRIDAY NIGHT. HOWEVER...THE 850MB TEMPS ARE NOT NEARLY AS COLD
AS THE CURRENT ARCTIC AIR SURGE...ONLY PROGGED TO DIP DOWN TO -20C
AT MOST.
FOR THE WEEKEND...A DEEP TROUGH IS FORECAST TO FORM JUST OFF OR ON
THE WEST COAST OF THE U.S....SETTING UP A PATTERN CHANGE AS 500MB
HEIGHTS RISE DOWNSTREAM ACROSS THE REST OF THE U.S.. EVENTUALLY A
LOW PRESSURE SYSTEM FORMS IN THE VICINITY OF WYOMING AND COLORADO BY
LATE SUNDAY...BUT MOISTURE RETURN TOWARDS THE FORECAST AREA IS STILL
LIMITED. THUS...A DRY WEEKEND WITH WARMING TEMPERATURES IS IN STORE.
HOW WARM WILL DEPEND ON HOW MUCH SNOW OCCURS WITH THE THURSDAY
SYSTEM. FOLLOWED THE CONSENSUS FOR HIGH TEMPERATURES FOR THE
WEEKEND...BUT THESE MAY STILL BE TOO COOL GIVEN 925MB TEMPS
CLIMBING TO 0 TO -4C BY 18Z SUNDAY PER 20.12Z GFS/ECMWF.
&&
.AVIATION...THROUGH 06Z TUESDAY
1125 PM CST SUN JAN 20 2013
PRESSURE GRADIENT HAS TIGHTENED THIS EVENING AS WEST TO NORTHWEST
WINDS NOW GUSTING TO 20 TO 25 KNOTS AT BOTH SITES. THIS TREND WILL
CONTINUE THROUGH THE NIGHT AND EVEN INTO MONDAY. SHOULD BEGIN TO
SEE A DECREASE AFTER 00Z TUESDAY...BUT STILL IN THE 10 TO 13 KNOT
RANGE. EXPECT ANY MVFR CEILINGS AND FLURRIES TO PUSH OUT OF THE
TAF SITES BY 09Z...WITH VFR CONDITIONS THEN EXPECTED AFTER THAT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST SUN JAN 20 2013
WI...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR WIZ017-029-032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR MNZ079-086>088-094>096.
IA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1121 PM CST SUN JAN 20 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE BUILDING SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS
BENEATH NORTHWEST FLOW ALOFT. EMBEDDED SHORTWAVE TROUGH WITHIN THIS
NW FLOW IS MOVING OVER WESTERN LAKE SUPERIOR EARLY THIS AFTERNOON AND
IS HELPING TO PRODUCE SNOW SHOWERS AND FLURRIES OVER NORTHERN
MINNESOTA WHICH ARE PUSHING INTO NORTHWEST WISCONSIN. THE NEXT PUSH
OF BITTERLY COLD ARCTIC AIR EXISTS BEHIND THIS SHORTWAVE WHERE
TEMPERATURES REMAIN BELOW 0F. FORECAST CONCERNS INCLUDE SMALL
PRECIP CHANCES THIS EVENING...THEN TEMPERATURES AND ASSOCIATED
HEADLINES.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE ACROSS THE UPPER PENINSULA
OVER THE REST OF THE AFTERNOON AND EARLY THIS EVENING. TAIL OF THE
VORT MAX WILL PUSH AN AREA OF CLOUDS AND FLURRIES ACROSS THE AREA
LATE THIS AFTERNOON AND THIS EVENING. HAVE ADDED THE CHANCE OF
FLURRIES TO THE FORECAST. LOW LEVEL WINDS LOOK TOO WESTERLY FOR
LAKE EFFECT SNOW TO BE MUCH OF AN ISSUE FOR VILAS COUNTY. BUT WITH
ENHANCEMENT FROM THE SHORTWAVE THIS EVENING...WILL KEEP A CHANCE OF
SNOW SHOWERS OVER VILAS AND ACCUMS LESS THAN A HALF INCH. TIMING
THE DEPARTURE OF THE CLOUDS IS DIFFICULT SINCE RH IN THE 900-800MB
LAYER REMAINS FAIRLY HIGH. SATELLITE IMAGERY SHOWS CLEARING TAKING
PLACE OVER NORTHERN MINNESOTA AND ONTARIO...SO THINK SKIES WILL AT
LEAST PARTIALLY CLEAR FROM WEST TO EAST AFTER MIDNIGHT TONIGHT.
TEMPERATURES WERE FIRMLY IN THE TEENS BELOW ZERO OVER NORTHERN
MINNESOTA THIS MORNING. WILL HAVE COMPARATIVELY MORE WIND THAN
FARTHER WEST...BUT STILL THINK WILL REACH IN THE LOW TEENS BELOW
ZERO OVER NORTH-CENTRAL WISCONSIN. WITH NW WINDS 7-12 KTS
TONIGHT...WIND CHILL READINGS WILL APPROACH 20 BELOW OVER
NORTH-CENTRAL WISCONSIN AROUND 06Z...AND OVER THE FOX VALLEY BY
10Z. WILL BEGIN THE NEW WIND CHILL HEADLINES AT THOSE TIMES.
MONDAY...NORTHWEST WINDS WILL CONTINUE TO POUR BITTERLY COLD ARCTIC
AIR ACROSS THE REGION...DROPPING 850MB TEMPS TO 28-29C BELOW ZERO.
ANOTHER WEAK SHORTWAVE WILL BE SWINGING ACROSS THE STATE. SOME
FLURRIES OR LIGHT SNOW NORTH OF LAKE WINNIPEG WITH THIS FEATURE AND
WILL ADD TO THE FORECAST OVER NORTH-CENTRAL AND CENTRAL WISCONSIN.
NW WINDS WILL REMAIN BREEZY...AND TEMPS WILL STRUGGLE TO REACH ABOVE
0F. WIND CHILL READINGS MAY BRIEFLY RISE ABOVE ADVISORY CRITERIA
FOR A FEW HOURS DURING THE AFTERNOON OVER THE FOX VALLEY AND
ADJACENT TO GREEN BAY. BUT HEADLINES WILL HAVE TO BE ISSUED AGAIN
BY 23-24Z...SO WILL JUST RUN HEADLINES THROUGH MONDAY NIGHT. HIGHS
RANGING FROM 6 BELOW OVER N-C WISCONSIN...TO ABOUT 6 ABOVE NEAR LAKE
MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. COLD ARCTIC AIR
INTRUSION WILL CONTINUE TO GRAB THE HEADLINES FOR THE FIRST HALF
OF THE WEEK. AN ONGOING WIND CHILL ADVISORY EXPECTED OVER WESTERN
AREAS TROUGH TUESDAY NOON. THE REST OF THE FORECAST AREA INCLUDING
THE LAKESHORE REGION WILL BE ADDED STARTING MONDAY EVENING AND
LASTING THROUGH NOON AS WELL AS THE CORE OF THE COLDEST AIR
FILTERS OVER THE AREA. MATTER OF FACT...LATER SHIFTS MAY POSSIBLY
NEED TO UPGRADE TO A WIND CHILL WARNING OVER PORTIONS OF NORTHERN
AND PARTS OF CENTRAL WISCONSIN MONDAY NIGHT. RESURGENT COLD AIR
AND NORTHWEST WINDS WILL CONTINUE LAKE EFFECT SNOW SHOWERS FAR
NORTH BUT DRY AIR MASS AND LOW INVERSIONS WILL LIKELY LIMIT PLUME
DEVELOPMENT.
WINDS WILL BE ON THE DECREASE LATER TUESDAY INTO WEDNESDAY AS A
COLD HIGH PRESSURE SYSTEM SETTLES OVER THE AREA. LAKE EFFECT SNOW
SHOWERS END AS WINDS TURN MORE SOUTHWEST...BUT ANOTHER COLD NIGHT
EXPECTED WITH THE LIGHTER WINDS UNDER THE HIGH PRESSURE SYSTEM.
MIN TEMPERATURES WILL BE IMPACTED BY CLOUDS THROUGH WEDNESDAY...BUT
GUIDANCE TENDS TO OVERDUE THE CLOUDS AT TIMES DUE TO THE RELATIVE
EASE TO SATURATE A COLD DRY AIR MASS. WITH SUCH A COLD AIR MASS
DROPPING IN FOR THE FIRST HALF OF THE WEEK...YOU WONDER HOW COLD
IT COULD HAVE BEEN WITH A FRESH DEEP SNOW COVER. WITH THE LIMITED
SNOW COVER...THE ARCTIC AIR WILL DRIVE AREA FROST DEPTHS DEEPER
THIS WEEK.
WEAK WAA STARTS ON WEDNESDAY AS A SHORT WAVE TROUGH DROPS INTO THE
NORTHERN GREAT LAKES REGION. MORE WIDESPREAD CLOUDS IN THE
BAROCLINIC ZONE FROM MT TO THE OHIO VALLEY TODAY MAY EDGE NORTH
INTO PARTS OF CENTRAL WISCONSIN WEDNESDAY AND CONTINUE TO SPREAD
NORTH THROUGH THURSDAY. LIGHT SNOW REMAINS IN THE FORECAST LATER
IN THE WEEK AS A CLIPPER SYSTEM DROPS INTO THE REGION AND PHASES
WITH SOME SOUTHERN STREAM ENERGY SOUTH AND EAST OF THE AREA. LAKE
EFFECT POTENTIAL INCREASES AGAIN THURSDAY NIGHT AND FRIDAY AS CAA
WITH NORTHWEST WINDS DEVELOP IN THE WAKE OF THE CLIPPER SYSTEM.
ANY LAKE EFFECT SNOW WILL END FRIDAY NIGHT AS A MODERATING
TEMPERATURE PATTERN STARTS WITH A RETURN TO A ZONAL FLOW WITH WAA
FOR THE WEEKEND.
&&
.AVIATION...FOR 06Z TAF ISSUANCE. PATCHES OF CLDS AND SOME
FLURRIES WL CONT TO STREAM SE FM TIME TO TIME UNDER COLD NWLY FLOW
ALOFT. EXPECT PRIMARILY VFR CONDITIONS.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 4 AM MONDAY TO NOON CST TUESDAY FOR
WIZ013-020-021-031-037>039-045-048-049-073-074.
WIND CHILL ADVISORY FROM 6 PM MONDAY TO NOON CST TUESDAY FOR
WIZ022-040-050.
WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ005-010>012-
018-019-030-035-036.
&&
$$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1143 PM MST SUN JAN 20 2013
.AVIATION...06Z TAF ISSUANCE...
EDGE OF LOWER CLOUD DECK REMAINS IN PLACE NEAR CHADRON BUT THE
VAST MAJORITY OF THE FORECAST AREA UNDER MOSTLY CLEAR SKIES AND
VFR AT THIS TIME. CHADRON SHOULD BE NEAR THE SOUTHERN EDGE OF THE
LOWER CLOUD DECK TONIGHT BUT THIS AREA OF LOW CLOUDS SHOULD SHIFT
EAST OF THE AREA AFTER SUNRISE.
WINDS WILL BE LIGHT TONIGHT BUT EXPECTING WESTERLY WINDS TO BECOME
GUSTY ACROSS SOUTHEAST WYOMING BY LATE MONDAY MORNING AND THROUGH
MONDAY AFTERNOON. GUSTS OVER 30 MPH CAN BE EXPECTED. WIND PRONE
AREAS SUCH AS BORDEAUX AND ARLINGTON WILL LIKELY SEE STRONG GUSTY
WINDS MONDAY NIGHT WITH GUSTS 50 MPH OR GREATER.
&&
.PREV DISCUSSION... /ISSUED 421 PM MST SUN JAN 20 2013/
AVIATION...00Z TAFS
LATEST HRRR MODEL RUN SHOWS IFR CEILINGS RETURNING TO KAIA AND
KCDR SHORTLY AFTER SUNSET. WRF SOUNDINGS FOR KCDR SHOWING A FAIRLY
STRONG STRATUS/FOG INVERSION SETTING UP OVER CHADRON AROUND 03Z
OR SO AND PERSISTING THROUGH MONDAY MORNING. CONFIDENCE IS HIGH
THAT EITHER FOG OR STRATUS WILL REDEVELOP OVER KCDR. WITH THE HRRR
SHOWING THIS STRATUS SPREADING SOUTH...TOOK KAIA DOWN SHORTLY
AFTER 03Z OR SO. ALSO NEED TO WATCH KSNY AS THE HRR SHOWS THE
SOUTHERN PANHANDLE GOING DOWN AFTER 05Z OR SO. FOR OUR SOUTHEAST
WYOMING AIRPORTS...VFR CONDITIONS WILL CONTINUE. THE EXCEPTION
COULD BE DOUGLAS WHERE THE BACKDOOR FRONT COULD PUSH INTO AND
DEVELOP SOME IFR/MVFR.
CLAYCOMB
PREV DISCUSSION... /ISSUED 247 PM MST SUN JAN 20 2013/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
UPCOMING WEEK CHARACTERIZED AS WINDY. TWO POSSIBLE HIGH WIND
EVENTS LOOK TO TAKE SHAPE THIS WEEK. A PESKY BACKDOOR COLD FRONT
HANGS ACROSS EASTERN PORTIONS OF THE CWA AFFECTING TEMPERATURES
MAINLY. THESE ARE THE FORECAST CHALLENGES WITH THIS FORECAST
PACKAGE.
CURRENTLY...BACKDOOR COLD FRONT HAS PUSHED SOUTHWEST THIS MORNING
AND CURRENTLY LAYS UP ALONG THE EASTERN SLOPES OF THE LARAMIE
RANGE EARLY THIS AFTERNOON. BEHIND THE FRONT...BLUSTERY NORTHEASTERLY
WINDS...COLDER TEMPERATURES ARE OCCURRING ACROSS SOUTHEAST WYOMING
EAST OF THE LARAMIE RANGE...WITH STRATUS OUT OVER THE NORTHERN
PANHANDLE. TEMPERATURES AT CHADRON AT 1 PM ARE BEING REPORTED AT
22 DEGREES WITH LOW 30S HERE AT CHEYENNE AND DOUGLAS. STRATUS LINE
CAN BE SEEN ON SATELLITE IMAGERY...GENERALLY FROM NEAR
BRIDGEPORT...NORTHWEST TO JUST NORTH OF TORRINGTON TO AROUND BILL
IN CONVERSE COUNTY.
FRONT LOOKS TO REMAIN IN PLACE THIS EVENING WITH COLD NORTH TO
NORTHEASTERLY WINDS EAST OF THE LARAMIE RANGE. OVERNIGHT LOWS WILL
BE QUITE COLD...WITH NEAR ZERO LOWS ACROSS THE NORTHERN PANHANDLE
AND LOW TEENS ALONG THE LARAMIE RANGE. FRONT REALLY DOES NOT BEGIN
TO MOVE EAST UNTIL MONDAY MID MORNING...BUT TAKES ITS SWEET TIME
EXITING THE NORTHERN PANHANDLE. MODEL SOUNDING TONIGHT SHOW A
PRETTY STRONG INVERSION SETTING UP OVER THE NORTHERN PANHANDLE AND
NIOBRARA COUNTY...SO WENT AHEAD AND KEPT INHERITED PATCHY FOG IN
THE FORECAST FOR THIS AREA.
A PRETTY STRONG GRADIENT IS SET UP FOR MONDAY WITH THE SLOW
MOVEMENT OF THIS FRONT. THE LATEST NAM/WRF WRKHGT PRODUCT SHOWING
THE CRAIG TO CASPER 850MB GRADIENT AROUND AT 65 METERS BY 06Z
TOMORROW NIGHT...700MB GRADIENT AROUND 51 METERS. GFS 700MB WINDS
INCREASE TO 50-55 KT MONDAY NIGHT. THOUGH NOT THE BEST WIND
DIRECTIONS FOR HIGH WINDS...DO BELIEVE THERE IS A GOOD POSSIBILITY
OF A GAP WIND EVENT SETTING UP FOR OUR WIND PRONE AREAS MONDAY
NIGHT INTO TUESDAY...SO WILL GO AHEAD WITH A HIGH WIND WATCH FOR
OUR WIND PRONE AREAS. MID SHIFT CAN TAKE ANOTHER LOOK BEFORE
ISSUING ANY UPGRADES.
BACKDOOR FRONT FINALLY MOVES EAST TUESDAY MORNING AND WINDS EASE
SOME THROUGH THE DAY. STILL LOOKS LIKE A COLD DAY OVERALL FOR THE
NORTHERN PANHANDLE TUESDAY WITH UPPER 30S AND LOW 40S FOR HIGHS.
ELSEWHERE...A BEAUTIFUL DAY LOOKS TO BE IN STORE WITH MID 50S
ACROSS THE SOUTHERN PANHANDLE ALL THE WAY TO THE EAST SLOPES OF
THE LARAMIE RANGE.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
THE 12Z MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT. A SHORTWAVE
RIDGE AXIS WILL SHIFT EAST ACROSS THE CWA WEDNESDAY...FOLLOWED BY
A SHORTWAVE TROUGH WEDNESDAY NIGHT AND THURSDAY MORNING. THE FAST
LOW-MID LEVEL TROPOSPHERIC FLOW AND LARGE SURFACE PRESSURE GRADIENT
ASSOCIATED WITH A STRONG COLD FRONT WILL PRODUCE MORE WIDESPREAD
STRONG AND GUSTY SURFACE WINDS AT THAT TIME. 700MB WINDS INCREASE
TO 70 KT OVER SOUTHEAST WYOMING AND 55 KT OVER THE WESTERN NEBRASKA
PANHANDLE WEDNESDAY EVENING. WINDS DECREASE THURSDAY WITH THE
PASSAGE OF THE UPPER TROUGH AND SURFACE COLD FRONT.
HIGH TEMPERATURES WEDNESDAY WILL BE 10 TO 20 DEGREES ABOVE NORMAL...
COOLING TO NEAR NORMAL THURSDAY AS CANADIAN HIGH PRESSURE BUILDS
SOUTHEAST ACROSS THE NORTHERN PLAINS. SURFACE TROUGH ALONG THE
LARAMIE RANGE THURSDAY NIGHT SHIFTS EAST INTO THE WESTERN NEBRASKA
PANHANDLE FRIDAY. A SURFACE RIDGE WILL BE PARKED OVER THE WASATCH
RANGE. WESTERLY SURFACE WINDS WILL BE BREEZY OVER THE MOUNTAINS AT
THAT TIME.
700MB TEMPERATURES MODERATE FROM -12C THURSDAY TO -2C FRIDAY.
DOWNSLOPE FLOW ON THE EASTERN PLAINS WILL RESULT IN 40-DEGREE
TEMPERATURES...WITH SOME 30S LINGERING IN EAST CENTRAL WYOMING AND
THE NORTHERN PANHANDLE. EVEN MILDER TEMPERATURES ARE IN THE FORECAST
FOR THE UPCOMING WEEKEND FOR THE EASTERN PLAINS AND PANHANDLE WITH
HIGHS IN THE 50S TO NEAR 60. IT WILL BE BREEZY OVER THE MOUNTAINS.
PRECIPITATION CHANCES DURING THE ENTIRE PERIOD WILL BE SLIM TO
NONE WITH LIMITED MOISTURE AND JET DYNAMICS WELL NORTH OF THE CWA.
AVIATION...18Z TAF ISSUANCE...
COLD FRONT HAS PUSHED THROUGH ALL EXCEPT AREAS WEST OF THE LARAMIE
RANGE LATE THIS MORNING. SURFACE WINDS SHIFTED FROM WESTERLY TO
NORTHERLY BEHIND THE FRONT AND WERE GUSTING AS HIGH AS 25 KT. A
LOW CLOUD DECK WAS PUSHING SOUTH ACROSS EASTERN WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE. CEILINGS RANGED FROM HIGH END IFR TO
MVFR. PREVAILING MVFR CEILINGS ARE FORECAST AT CHADRON AND ALLIANCE
THROUGH TONIGHT. VFR CONDITIONS WILL PREVAIL FOR THE SOUTHEAST
WYOMING AERODROMES THROUGH TONIGHT...WITH GUSTY WESTERLY WINDS
DEVELOPING MONDAY MORNING.
FIRE WEATHER...
STRONG AND GUSTY WINDS ARE THE THEME FOR FIRE WEATHER THIS WEEK.
WINDS WILL EASE SOME THIS EVENING AFTER SUNSET WITH OVERNIGHT
HUMIDITIES RANGING FROM 70 PERCENT OUT BY RAWLINS TO 100 PERCENT
IN THE PANHANDLE. STRONG WINDS EXPECTED MONDAY NIGHT INTO TUESDAY
IN OUR WIND PRONE AREAS WITH AFTERNOON HUMIDITIES FALLING INTO THE
LOW TEENS EAST OF THE LARAMIE RANGE TUESDAY AFTERNOON. A STRONGER
AND MORE WIDESPREAD HIGH WIND EVENT LOOKS TO TAKE SHAPE WEDNESDAY
NIGHT INTO THURSDAY AS A COLD FRONT PASSES THROUGH THE AREA AND
LOW PRESSURE TRACKS THROUGH MONTANA. WIDESPREAD WIND GUSTS IN
EXCESS OF 60 MPH ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY...
BEFORE SHIFTING NORTHWEST AND EASING THURSDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM 9 PM MONDAY TO 8 AM TUESDAY FOR WYZ106-
WYZ110-WYZ116.
NE...NONE.
&&
$$
AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1058 PM MST SUN JAN 20 2013
.AVIATION...12Z TAF ISSUANCE...
EDGE OF LOWER CLOUD DECK REMAINS IN PLACE NEAR CHADRON BUT THE
VAST MAJORITY OF THE FORECAST AREA UNDER MOSTLY CLEAR SKIES AND
VFR AT THIS TIME. CHADRON SHOULD BE NEAR THE SOUTHERN EDGE OF THE
LOWER CLOUD DECK TONIGHT BUT THIS AREA OF LOW CLOUDS SHOULD SHIFT
EAST OF THE AREA AFTER SUNRISE.
WINDS WILL BE LIGHT TONIGHT BUT EXPECTING WESTERLY WINDS TO BECOME
GUSTY ACROSS SOUTHEAST WYOMING BY LATE MONDAY MORNING AND THROUGH
MONDAY AFTERNOON. GUSTS OVER 30 MPH CAN BE EXPECTED. WIND PRONE
AREAS SUCH AS BORDEAUX AND ARLINGTON WILL LIKELY SEE STRONG GUSTY
WINDS MONDAY NIGHT WITH GUSTS 50 MPH OR GREATER.
&&
.PREV DISCUSSION... /ISSUED 421 PM MST SUN JAN 20 2013/
AVIATION...00Z TAFS
LATEST HRRR MODEL RUN SHOWS IFR CEILINGS RETURNING TO KAIA AND
KCDR SHORTLY AFTER SUNSET. WRF SOUNDINGS FOR KCDR SHOWING A FAIRLY
STRONG STRATUS/FOG INVERSION SETTING UP OVER CHADRON AROUND 03Z
OR SO AND PERSISTING THROUGH MONDAY MORNING. CONFIDENCE IS HIGH
THAT EITHER FOG OR STRATUS WILL REDEVELOP OVER KCDR. WITH THE HRRR
SHOWING THIS STRATUS SPREADING SOUTH...TOOK KAIA DOWN SHORTLY
AFTER 03Z OR SO. ALSO NEED TO WATCH KSNY AS THE HRR SHOWS THE
SOUTHERN PANHANDLE GOING DOWN AFTER 05Z OR SO. FOR OUR SOUTHEAST
WYOMING AIRPORTS...VFR CONDITIONS WILL CONTINUE. THE EXCEPTION
COULD BE DOUGLAS WHERE THE BACKDOOR FRONT COULD PUSH INTO AND
DEVELOP SOME IFR/MVFR.
CLAYCOMB
PREV DISCUSSION... /ISSUED 247 PM MST SUN JAN 20 2013/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
UPCOMING WEEK CHARACTERIZED AS WINDY. TWO POSSIBLE HIGH WIND
EVENTS LOOK TO TAKE SHAPE THIS WEEK. A PESKY BACKDOOR COLD FRONT
HANGS ACROSS EASTERN PORTIONS OF THE CWA AFFECTING TEMPERATURES
MAINLY. THESE ARE THE FORECAST CHALLENGES WITH THIS FORECAST
PACKAGE.
CURRENTLY...BACKDOOR COLD FRONT HAS PUSHED SOUTHWEST THIS MORNING
AND CURRENTLY LAYS UP ALONG THE EASTERN SLOPES OF THE LARAMIE
RANGE EARLY THIS AFTERNOON. BEHIND THE FRONT...BLUSTERY NORTHEASTERLY
WINDS...COLDER TEMPERATURES ARE OCCURRING ACROSS SOUTHEAST WYOMING
EAST OF THE LARAMIE RANGE...WITH STRATUS OUT OVER THE NORTHERN
PANHANDLE. TEMPERATURES AT CHADRON AT 1 PM ARE BEING REPORTED AT
22 DEGREES WITH LOW 30S HERE AT CHEYENNE AND DOUGLAS. STRATUS LINE
CAN BE SEEN ON SATELLITE IMAGERY...GENERALLY FROM NEAR
BRIDGEPORT...NORTHWEST TO JUST NORTH OF TORRINGTON TO AROUND BILL
IN CONVERSE COUNTY.
FRONT LOOKS TO REMAIN IN PLACE THIS EVENING WITH COLD NORTH TO
NORTHEASTERLY WINDS EAST OF THE LARAMIE RANGE. OVERNIGHT LOWS WILL
BE QUITE COLD...WITH NEAR ZERO LOWS ACROSS THE NORTHERN PANHANDLE
AND LOW TEENS ALONG THE LARAMIE RANGE. FRONT REALLY DOES NOT BEGIN
TO MOVE EAST UNTIL MONDAY MID MORNING...BUT TAKES ITS SWEET TIME
EXITING THE NORTHERN PANHANDLE. MODEL SOUNDING TONIGHT SHOW A
PRETTY STRONG INVERSION SETTING UP OVER THE NORTHERN PANHANDLE AND
NIOBRARA COUNTY...SO WENT AHEAD AND KEPT INHERITED PATCHY FOG IN
THE FORECAST FOR THIS AREA.
A PRETTY STRONG GRADIENT IS SET UP FOR MONDAY WITH THE SLOW
MOVEMENT OF THIS FRONT. THE LATEST NAM/WRF WRKHGT PRODUCT SHOWING
THE CRAIG TO CASPER 850MB GRADIENT AROUND AT 65 METERS BY 06Z
TOMORROW NIGHT...700MB GRADIENT AROUND 51 METERS. GFS 700MB WINDS
INCREASE TO 50-55 KT MONDAY NIGHT. THOUGH NOT THE BEST WIND
DIRECTIONS FOR HIGH WINDS...DO BELIEVE THERE IS A GOOD POSSIBILITY
OF A GAP WIND EVENT SETTING UP FOR OUR WIND PRONE AREAS MONDAY
NIGHT INTO TUESDAY...SO WILL GO AHEAD WITH A HIGH WIND WATCH FOR
OUR WIND PRONE AREAS. MID SHIFT CAN TAKE ANOTHER LOOK BEFORE
ISSUING ANY UPGRADES.
BACKDOOR FRONT FINALLY MOVES EAST TUESDAY MORNING AND WINDS EASE
SOME THROUGH THE DAY. STILL LOOKS LIKE A COLD DAY OVERALL FOR THE
NORTHERN PANHANDLE TUESDAY WITH UPPER 30S AND LOW 40S FOR HIGHS.
ELSEWHERE...A BEAUTIFUL DAY LOOKS TO BE IN STORE WITH MID 50S
ACROSS THE SOUTHERN PANHANDLE ALL THE WAY TO THE EAST SLOPES OF
THE LARAMIE RANGE.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
THE 12Z MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT. A SHORTWAVE
RIDGE AXIS WILL SHIFT EAST ACROSS THE CWA WEDNESDAY...FOLLOWED BY
A SHORTWAVE TROUGH WEDNESDAY NIGHT AND THURSDAY MORNING. THE FAST
LOW-MID LEVEL TROPOSPHERIC FLOW AND LARGE SURFACE PRESSURE GRADIENT
ASSOCIATED WITH A STRONG COLD FRONT WILL PRODUCE MORE WIDESPREAD
STRONG AND GUSTY SURFACE WINDS AT THAT TIME. 700MB WINDS INCREASE
TO 70 KT OVER SOUTHEAST WYOMING AND 55 KT OVER THE WESTERN NEBRASKA
PANHANDLE WEDNESDAY EVENING. WINDS DECREASE THURSDAY WITH THE
PASSAGE OF THE UPPER TROUGH AND SURFACE COLD FRONT.
HIGH TEMPERATURES WEDNESDAY WILL BE 10 TO 20 DEGREES ABOVE NORMAL...
COOLING TO NEAR NORMAL THURSDAY AS CANADIAN HIGH PRESSURE BUILDS
SOUTHEAST ACROSS THE NORTHERN PLAINS. SURFACE TROUGH ALONG THE
LARAMIE RANGE THURSDAY NIGHT SHIFTS EAST INTO THE WESTERN NEBRASKA
PANHANDLE FRIDAY. A SURFACE RIDGE WILL BE PARKED OVER THE WASATCH
RANGE. WESTERLY SURFACE WINDS WILL BE BREEZY OVER THE MOUNTAINS AT
THAT TIME.
700MB TEMPERATURES MODERATE FROM -12C THURSDAY TO -2C FRIDAY.
DOWNSLOPE FLOW ON THE EASTERN PLAINS WILL RESULT IN 40-DEGREE
TEMPERATURES...WITH SOME 30S LINGERING IN EAST CENTRAL WYOMING AND
THE NORTHERN PANHANDLE. EVEN MILDER TEMPERATURES ARE IN THE FORECAST
FOR THE UPCOMING WEEKEND FOR THE EASTERN PLAINS AND PANHANDLE WITH
HIGHS IN THE 50S TO NEAR 60. IT WILL BE BREEZY OVER THE MOUNTAINS.
PRECIPITATION CHANCES DURING THE ENTIRE PERIOD WILL BE SLIM TO
NONE WITH LIMITED MOISTURE AND JET DYNAMICS WELL NORTH OF THE CWA.
AVIATION...18Z TAF ISSUANCE...
COLD FRONT HAS PUSHED THROUGH ALL EXCEPT AREAS WEST OF THE LARAMIE
RANGE LATE THIS MORNING. SURFACE WINDS SHIFTED FROM WESTERLY TO
NORTHERLY BEHIND THE FRONT AND WERE GUSTING AS HIGH AS 25 KT. A
LOW CLOUD DECK WAS PUSHING SOUTH ACROSS EASTERN WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE. CEILINGS RANGED FROM HIGH END IFR TO
MVFR. PREVAILING MVFR CEILINGS ARE FORECAST AT CHADRON AND ALLIANCE
THROUGH TONIGHT. VFR CONDITIONS WILL PREVAIL FOR THE SOUTHEAST
WYOMING AERODROMES THROUGH TONIGHT...WITH GUSTY WESTERLY WINDS
DEVELOPING MONDAY MORNING.
FIRE WEATHER...
STRONG AND GUSTY WINDS ARE THE THEME FOR FIRE WEATHER THIS WEEK.
WINDS WILL EASE SOME THIS EVENING AFTER SUNSET WITH OVERNIGHT
HUMIDITIES RANGING FROM 70 PERCENT OUT BY RAWLINS TO 100 PERCENT
IN THE PANHANDLE. STRONG WINDS EXPECTED MONDAY NIGHT INTO TUESDAY
IN OUR WIND PRONE AREAS WITH AFTERNOON HUMIDITIES FALLING INTO THE
LOW TEENS EAST OF THE LARAMIE RANGE TUESDAY AFTERNOON. A STRONGER
AND MORE WIDESPREAD HIGH WIND EVENT LOOKS TO TAKE SHAPE WEDNESDAY
NIGHT INTO THURSDAY AS A COLD FRONT PASSES THROUGH THE AREA AND
LOW PRESSURE TRACKS THROUGH MONTANA. WIDESPREAD WIND GUSTS IN
EXCESS OF 60 MPH ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY...
BEFORE SHIFTING NORTHWEST AND EASING THURSDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM 9 PM MONDAY TO 8 AM TUESDAY FOR WYZ106-
WYZ110-WYZ116.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...
LONG TERM/AVIATION...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
807 AM CST MON JAN 21 2013
.DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* PATCHY MVFR CIGS AND SNOW FLURRIES STEADILY IMPROVING TO VFR AND
DRY CONDS BY MIDDAY.
* GUSTY WEST-NORTHWEST WINDS AROUND 25 KTS THROUGH THE DAY.
RATZER/BEACH
//DISCUSSION...UPDATED 12Z...
A REINFORCING PUSH OF COLD ARCTIC AIR WAS MOVING ACROSS NORTHERN
ILLINOIS EARLY THIS MORNING...ACCOMPANIED BY AN UPPER LEVEL
DISTURBANCE WHICH WAS HELPING TO PRODUCE PATCHY LIGHT SNOW SHOWERS
AND FLURRIES. THE COLD FRONT AND UPPER LEVEL WAVE SHOULD PUSH
ACROSS THE TERMINALS BY MID MORNING...WITH EVENTUAL SCATTERING OF
LOWER CLOUDS...AND BLUSTERY WINDS IN THE 290-300 DEGREE RANGE
GUSTING AROUND 25 KTS FOR THE REMAINDER OF THE DAY. DUE TO THE DRY
NATURE OF THE COLD ARCTIC AIR...COVERAGE OF MVFR CIGS AND SNOW
SHOWERS HAS BEEN SOMEWHAT PATCHY OVERNIGHT/EARLY THIS MORNING...
AND WILL LIKELY CONTINUE TO BE THE SAME UNTIL CLOUDS DECREASE
LATER THIS MORNING WITH INCREASING SUBSIDENCE BEHIND THE DEPARTING
UPPER TROUGH.
WINDS WILL REMAIN GUSTY EVEN INTO THE EVENING HOURS TONIGHT...
THOUGH GUST SPEEDS SHOULD GRADUALLY DECREASE AFTER SUNSET.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN FLURRIES BEFORE 16Z WITH PATCHY MVFR CIGS.
* HIGH CONFIDENCE IN CIGS IMPROVING TO VFR BY MIDDAY.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
RATZER/BEACH
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014...6 PM MONDAY TO 9 AM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
529 AM CST MON JAN 21 2013
.DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* PATCHY MVFR CIGS AND SNOW FLURRIES EARLY THIS MORNING.
* GUSTY WEST-NORTHWEST WINDS AROUND 25 KTS THROUGH THE DAY.
RATZER
//DISCUSSION...UPDATED 12Z...
A REINFORCING PUSH OF COLD ARCTIC AIR WAS MOVING ACROSS NORTHERN
ILLINOIS EARLY THIS MORNING...ACCOMPANIED BY AN UPPER LEVEL
DISTURBANCE WHICH WAS HELPING TO PRODUCE PATCHY LIGHT SNOW SHOWERS
AND FLURRIES. THE COLD FRONT AND UPPER LEVEL WAVE SHOULD PUSH
ACROSS THE TERMINALS BY MID MORNING...WITH EVENTUAL SCATTERING OF
LOWER CLOUDS...AND BLUSTERY WINDS IN THE 290-300 DEGREE RANGE
GUSTING AROUND 25 KTS FOR THE REMAINDER OF THE DAY. DUE TO THE DRY
NATURE OF THE COLD ARCTIC AIR...COVERAGE OF MVFR CIGS AND SNOW
SHOWERS HAS BEEN SOMEWHAT PATCHY OVERNIGHT/EARLY THIS MORNING...
AND WILL LIKELY CONTINUE TO BE THE SAME UNTIL CLOUDS DECREASE
LATER THIS MORNING WITH INCREASING SUBSIDENCE BEHIND THE DEPARTING
UPPER TROUGH.
WINDS WILL REMAIN GUSTY EVEN INTO THE EVENING HOURS TONIGHT...
THOUGH GUST SPEEDS SHOULD GRADUALLY DECREASE AFTER SUNSET.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS/FLURRIES THIS MORNING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014...6 PM MONDAY TO 9 AM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
552 AM CST MON JAN 21 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 219 AM CST MON JAN 21 2013
A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION HAS RESULTED
IN AN ARCTIC AIR INTRUSION INTO THE NORTHERN PLAINS EARLY THIS
MORNING. THERE WERE TWO FRONTAL SURGES, ONE THAT PASSED LATE SUNDAY
AFTERNOON THROUGH WESTERN KANSAS, AND A MORE PRONOUNCED FRONT
LOCATED ACROSS CENTRAL NEBRASKA AS OF 2 AM. THIS 2ND COLDER SURGE
WILL NOT MAKE IT THROUGH WESTERN KANSAS TODAY. HOWEVER, A PATCH OF
LOW LEVEL MOISTURE AND LOW CLOUDS, WITH CEILINGS AROUND 1000FT WAS
TRAPPED ACROSS WEST CENTRAL KANSAS NEAR THE SURFACE RIDGE IN THE WAKE
OF THE FIRST FRONT. WEAK LEE TROUGHING IS EXPECTED TO DEVELOP TODAY
AS A SMALL COMPONENT OF MID-LEVEL FLOW ACROSS THE ROCKIES RESULTS
IN PRESSURE FALLS. THIS WOULD TYPICALLY CLEAR THE CLOUDS OUT OF
WESTERN KANSAS. HOWEVER, THERE IS A CHANCE THAT A SHARP LOW-LEVEL
INVERSION WILL DEVELOP AND PERSIST IN SPITE OF THE DAYTIME
HEATING. THE 00Z AND 06Z NAM SHOW NO SIGN OF THIS SCENARIO, WITH
TEMPERATURES IN THE MID 40S AT PLACES LIKE SCOTT CITY AND DIGHTON.
BUT THE 05Z RAP SHOWS A SMALL POCKET OF COLDER AIR, WITH HIGHS
STAYING IN THE MID TO UPPER 30S THERE, WITH 40S FURTHER EAST AND
NEAR 50 IN FAR SOUTHWEST KANSAS. THIS IS A DEPARTURE FROM THE 03Z
RAP WHICH WAS SIMILAR TO THE NAM. SO THE MAIN FORECAST PROBLEM
THIS MORNING IS WHETHER LOW CLOUDS WILL PERSIST ACROSS WEST
CENTRAL KANSAS, ALONG WITH THE COOLER TEMPERATURES. WE OPTED TO GO
GENERALLY WITH A NAM SOLUTION, EXCEPT KEEP TEMPERATURES SEVERAL
DEGREES COOLER WHERE THE RAP IS SHOWING THE LOW LEVEL COLD POOL.
IT IS POSSIBLE THAT GIVEN THE DEVELOPING LOW LEVEL SOUTH TO
SOUTHWEST WINDS THAT THE COLD POOL MAY SHIFT NORTH OF INTERSTATE
70 BY LATE AFTERNOON.
A NORTHWEST TO SOUTHEAST ORIENTED BAROCLINIC ZONE WILL REMAIN ACROSS
THE CENTRAL AND EASTERN PLAINS TONIGHT AS THE AFOREMENTIONED
SECONDARY COLD FRONT STALLS OUT FROM WESTERN NEBRASKA INTO EASTERN
KANSAS. ANY REMAINING LOW CLOUDS SHOULD CLEAR, EXCEPT FOR POSSIBLY A
FEW HIGHER LEVEL CLOUDS. TEMPERATURES SHOULD FALL INTO THE UPPER TEENS
TO LOWER 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CST MON JAN 21 2013
THE UPPER LEVEL LOW PRESSURE SYSTEM CENTERED OVER THE HUDSON BAY
REGION WILL MIGRATE EAST INTO THE CANADIAN MARITIME LATER THIS WEEK
WHICH WILL ALLOW HEIGHTS TO RISE SOMEWHAT OVER THE EASTERN PART OF
THE U.S. FARTHER WEST, A PERSISTENT UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL CONTINUE IN PLACE OVER THE WEST COAST. A SHORTWAVE
TROUGH WILL PLOW THROUGH THE UPPER RIDGE AND MOVE OUT OVER THE
NORTHERN AND CENTRAL PLAINS ON THURSDAY. THE OPERATIONAL GFS IS A
LITTLE SLOWER THAN THE OTHER MODELS WITH THE TIMING OF THIS FEATURE.
THE GFS ENSEMBLE MEMBERS TEND TO BE FASTER THAN THE OPERATIONAL RUN
SO WILL LEAN TOWARD THE EURO AND CANADIAN SOLUTIONS.
A WARMING TREND WILL BE IN PROGRESS FROM TUESDAY INTO WEDNESDAY AS
UPPER LEVEL RIDGING BUILDS INTO THE CENTRAL PLAINS. THE MODELS SHOW
A WEAK FRONTAL BOUNDARY PUSHING SOUTHWESTWARD INTO THE HIGH PLAINS
WEDNESDAY AFTERNOON IN RESPONSE TO A SHORTWAVE TROUGH MOVING THROUGH
THE UPPER MIDWEST AND GREAT LAKES. TEMPERATURES SHOULD BE ABLE TO
RISE INTO THE LOWER 50S AROUND HAYS WITH HIGHS CLIMBING INTO THE MID
60S AT ELKHART. THE NEXT COLD FRONT WILL BE PUSHING SOUTH ACROSS
SOUTHWEST KANSAS ON THURSDAY. THIS WILL DROP TEMPERATURES BACK SOME
ON THURSDAY. ANOTHER SURGE OF EVEN COLDER AIR WILL BE MOVING DOWN
THROUGH THE MIDWEST ON THURSDAY NIGHT BUT THE BULK OF THIS SHOULD
STAY IN EASTERN KANSAS.
THE MODELS SHOW THE UPPER FLOW BECOMING MORE ZONAL ONCE AGAIN BY THE
UPCOMING WEEKEND. DOWNSLOPE FLOW WILL BRING WARMER TEMPERATURES BACK
OUT ACROSS THE HIGH PLAINS WHICH SHOULD ALLOW TEMPERATURES TO WARM
BACK INTO THE 50S AND POSSIBLY THE LOW 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 551 AM CST MON JAN 21 2013
A DECK OF STRATUS OVER FAR WESTERN KANSAS WILL SLOWLY SPREAD NORTHEAST
THROUGH THE EARLY MORNING HOURS. THIS DECK IS JUST WEST OF GARDEN
CITY AND COULD IMPACT THE AIRPORT WITH MVFR CIGS THROUGH THE MORNING
HOURS AND COULD MOVE INTO THE HAYS AREA BY LATE MORNING. THE CLOUDS
SHOULD BE DIMINISHING BY LATE MORNING AND EARLY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 21 48 25 / 0 0 0 0
GCK 44 20 51 24 / 0 0 0 0
EHA 50 26 58 29 / 0 0 0 0
LBL 47 24 54 26 / 0 0 0 0
HYS 38 17 42 21 / 0 0 0 0
P28 40 21 47 27 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...GERARD
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS TOPEKA KS
500 AM CST MON JAN 21 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
NAM AND GFS SHOW THE CLOUD DECK OVER NEB MOVING INTO THE TERMINALS
BY LATE MORNING. FOR THE MOST PART OBS SHOW CIGS AROUND 3 TO 4
KFT...AND EXPECT THIS TO PERSIST AS THE CLOUDS MOVE SOUTH. THE
EXCEPTION MAY BE IF SOME FLURRIES ARE ABLE TO DEVELOP. WITH A VERY
COLD AIRMASS IN PLACE...TEMPS IN THE CLOUD DECK ARE IN THE FAVORABLE
RANGE FOR ICE CRYSTAL GROWTH. WHILE FORCING IS NOT THAT
IMPRESSIVE...MOST OF THE SHORT TERM GUIDANCE SUGGESTS SOME WEAK
VERTICAL MOTION IS POSSIBLE...ESPECIALLY OVERNIGHT AS 850 WINDS VEER
TO THE WEST AND SOUTHWEST INCREASING ISENTROPIC LIFT AND ADVECTING
HIGHER THETA-E AIR INTO THE COLD AIR. LOCATION OF FURRIERS IS A
LITTLE UNCLEAR AS MODELS SHOW THE BEST SATURATION JUST TO THE
NORTHEAST OF TOP...SO WILL NOT MENTION IN THE FORECAST AT THIS TIME.
IF FLURRIES DO FORM...THERE COULD BE SOME BRIEF MVFR CONDITIONS THIS
AFTERNOON OR OVERNIGHT.
WOLTERS
&&
.PREV DISCUSSION... /309 AM CST MON JAN 21 2013/
TODAY AND TUESDAY...COLD AIR CONTINUES TO TRICKLE INTO THE FORECAST
AREA THIS MORNING AS THE 8Z RAP INDICATES AN AREA OF SURFACE HIGH
PRESSURE STRETCHING FROM THE CENTRAL PLAINS NORTHWESTWARD INTO
CENTRAL CANADA. THIS HIGH PRESSURE IS BRINGING LIGHT NORTHWEST
WINDS...WHICH IS ALLOWING THE COLD AIR TO ADVECT INTO THE AREA.
11-3.9 MICRON SATELLITE SHOWS AN AREA OF STRATUS STRETCHING FROM
KFNB NORTHWESTWARD THROUGH CENTRAL NEBRASKA AND INTO SOUTHWESTERN
SOUTH DAKOTA. OBSERVATIONS FROM CENTRAL NEBRASKA UNDER THIS STRATUS
ARE INDICATING LIGHT SNOW FALL. AS THE STRATUS STRETCHES
SOUTHEASTWARD INTO NORTHEAST KANSAS IT MAY BRING WITH IT A FEW SNOW
FLURRIES...MAINLY NORTH OF INTERSTATE 70. FORECAST SOUNDINGS
THROUGHOUT THE DAY SHOW A MODEST AMOUNT OF UPWARD MOTION IN THE
LOWEST FEW THOUSAND FEET...WHICH WILL AID IN STRATUS DEVELOPMENT AND
WITH THE COLUMN BEING SO COLD IT WILL NOT TAKE MUCH LIFT NOR FURTHER
COOLING TO PRODUCE A FEW FLURRIES. EXPECT SCATTERED OFF-AND-ON
FLURRIES TO REMAIN POSSIBLE THROUGH THE DAYTIME AND OVERNIGHT HOURS
ON MONDAY/MONDAY NIGHT. DUE TO THE CLOUD COVER AND COLD AIR ADVECTION
DO NOT EXPECT TEMPERATURES ON MONDAY TO WARM MUCH...AS THE GOING
HIGH FOR MONDAY WILL BE IN THE LOWER TO MID 20S NORTH OF INTERSTATE
70 AND IN THE LOWER 30S SOUTH OF I-70. DRY AIR WORKS ITS WAY INTO
THE AREA BY MONDAY NIGHT CAUSING THE STRATUS TO MOVE TO THE EAST BY
MONDAY NIGHT ALLOWING SKIES TO CLEAR BY TUESDAY. IT WILL TAKE
ANOTHER DAY TO GET THE COLD AIR OUT OF THE AREA...SO FOR TUESDAY
EXPECTING ONLY A MINOR INCREASE IN TEMPS...AS DAY TIME HIGHS FOR
TUESDAY WILL REACH NO HIGHER THAN THE LOWER TO MID 30S...WITH
POSSIBLY 40 DEGREE TEMPS IN CENTRAL KANSAS.
WEDNESDAY THROUGH SUNDAY...WEDNESDAY WILL BRING A BRIEF BREAK FROM
THE ARCTIC AIR AS WARMER AIR TRIES TO MAKE ITS WAY INTO THE FORECAST
AREA. 925 MB TEMPS GO FROM -10 TO -15 C ON TUESDAY TO AROUND 5 C
WEDNESDAY...WHICH IF MIXED TO THE SURFACE SHOULD BRING TEMPS BACK
INTO THE MID TO UPPER 40S ON WED. PERHAPS AREAS OF CENTRAL AND EAST
CENTRAL KANSAS COULD SEE SOME 50 TO 53 DEGREE TEMPS WED. BY THURSDAY
ANOTHER COLD AIR MASS PLUNGES INTO THE CENTRAL PLAINS CAUSING TEMPS
TO RETURN TO NEAR NORMAL FOR THURSDAY THROUGH SATURDAY...WITH FRIDAY
STRUGGLING TO REACH THE 30S. WARM AIR ADVECTION ON THURSDAY
EVENING/THURSDAY NIGHT WILL BRING INCREASING CLOUDS...AND PERHAPS
SOME VERY LIGHT RAIN IN FAR EAST CENTRAL KANSAS. WITH SURFACE TEMPS
DROPPING NEAR FREEZING AND PERHAPS BELOW FREEZING THURSDAY NIGHT
THERE COULD BE A PERIOD OF VERY LIGHT FREEZING RAIN...BUT THAT
PERIOD SHOULD NOT LAST LONG...NOR IS ANY ACCUMULATION EXPECTED.
A WARM UP FROM THE COLD TEMPS IS EXPECTED BY THE END OF THE WEEKEND
AS FORECAST HIGHS FOR SUNDAY LOOK LIKE THEY WILL REACH THE LOWER TO
POSSIBLY MID 50S AS WARM AIR MOVES BACK INTO THE AREA AND MID LEVEL
RIDGING TAKES OVER. BY EARLY NEXT WEEK WITH INCREASING MID LEVEL
HEIGHTS MOVING OVER THE AREA AND A WESTERLY DOWN SLOPE FLOW THE
LATTER HALF OF THE WEEKEND AND EARLY PART OF NEXT WEEK LOOK FAIRLY
PLEASANT.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
647 AM EST MON JAN 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EST MON JAN 21 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
E AND CENTRAL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF THE W
COAST. COLDEST AIRMASS OF THE SEASON HAS FLOODED INTO THE UPR LKS IN
THE NW LLVL FLOW WITH H85 TEMPS AS LO AS -25C OVER THE WRN CWA. 00Z
H85 TEMP WAS AS LO AS -30C AT YPL. THE PASSAGE OF THIS COLD AIRMASS
OVER THE RELATIVELY WARM WATERS OF LK SUP HAS RESULTED IN NMRS LK
EFFECT SHSN. BUT LLVL FLOW HAS BACKED TO MORE WNW IN ADVANCE OF NEXT
SHRTWV DROPPING SEWD THRU NW ONTARIO TOWARD ISLE ROYALE. IN CONCERT
WITH NEAR SFC WSW WIND ENHANCED BY LAND BREEZE FLOW OF SUB ZERO
TEMPS TOWARD WARMER LK SUP...THIS WSHFT IS CONFINING THE BULK OF THE
LES TO AREAS OVER THE W MAINLY N OF THE PORCUPINE MTNS THRU THE
KEWEENAW AND TO AREAS NEAR LK SUP E OF PICTURED ROCKS LAKESHORE. ONE
IMPACT OF THE VERY COLD AIRMASS IS THE DGZ HAS NEARLY DISAPPEARED AT
LEAST OVER THE W...RESULTING IN VERY FINE SN FLAKES THAT EFFICIENTLY
REDUCE THE VSBY WHILE LIMITING SN ACCUMS. SKIES ARE GENERALLY
CLR-PCLDY OVER AREAS TO THE S OF THE LES...WHICH HAS ALLOWED TEMPS
TO FALL BLO ZERO. THE WIND CHILL EARLY THIS MRNG HAS DROPPED AS LO
AS -25F AT IWD. TO THE NW...THERE IS AN AREA OF CLDS ASSOCIATED WITH
THE DIGGING SHRTWV AND FAIRLY DEEP MSTR DEPICTED ON THE 00Z YPL
RAOB. THERE ARE EVEN SOME REPORTS OF -SN IN ONTARIO JUST N OF THE MN
BORDER DESPITE PWATS OF 0.06 INCH REPORTED AT INL/YPL.
TODAY...AS SHRTWV/ACCOMPANYING DEEP LYR QVECTOR CNVGC/MSTR JUST TO
THE NW DIG SEWD ACROSS THE CWA THIS MRNG...EXPECT LES INTENSITY TO
INCRS SOMEWHAT WHILE NEAR -30C H85 TEMPS ARE DRAWN INTO WRN UPR MI.
ALTHOUGH DEEPENING CONVECTIVE DEPTH/MSTR TO ABV 10K FT AS SHOWN ON
FCST SDNGS WOULD NORMALLY BE A CONCERN FOR VERY HEAVY LES...NEAR
ABSENCE OF DGZ WITH SUCH COLD H85 TEMPS INDICATES SN FLAKES WL BE
VERY SMALL...ESPECIALLY OVER THE W WITH SHORTER FETCH/LESS
MODIFICATION OF THE COLD/DRY AIRMASS. ONE ADVANTAGE FOR HEAVIER SHSN
WOULD BE INCRSG LLVL CNVGC. SINCE THE LLVL FLOW WL VEER MORE TO THE
NW WITH PASSAGE OF SHRTWV...EXPECT LES BANDS TO DRIFT BACK TO THE S.
THIS VEERING FLOW OFF THE SFC WL LIKELY RESULT IN SHARPER LLVL CNVGC
OVER THE W BTWN LAND BREEZE FLOWS OFF WI/INTERIOR WRN UPR MI AND
OVER THE E WITH THESE FLOWS OFF CNTRL UPR MI AND SE ONTARIO/ERN UPR
MI. GENERAL CONSENSUS OF HIER RES MODELS SHOWS THE BACK CHC FOR THE
SHARPER CNVGC WL BE OVER THE W FM THE PORCUPINE MTNS TO NEAR TWIN
LAKES IN CNTRL HOUGHTON COUNTY AND IN AREAS E OF MUNISING AND AS FAR
S AS ABOUT HIGHWAY M-28. THESE HI RES MODELS ALL SHOW THE SHARPEST
CNVGC/HIER QPF OVER THE ERN CWA...AND SOME INDICATE THE HEAVIER SHSN
WL PUSH FARTHER INLAND THAN M-28. ON THE OTHER HAND...SOME OF THE
MODELS INDICATE A LK INDUCED VORTEX MAY DVLP NEAR GRAND MARAIS AND
LIMIT THE INLAND SPREAD OF THE SHSN. AS FOR SN AMOUNTS...OLD LES
CHART INDICATES SN FALL OF 5-9 INCHES/12 HRS GIVEN EXPECTED
CONDITIONS. BUT RECENT EXPERIENCE SUGS THE NEAR ABSENCE OF DGZ CUTS
THESE TOTALS BY ABOUT HALF. WITH SHARPER LLVL CNVGC/MORE LK
MODERATION THAT WOULD MAINTAIN HIER LLVL TEMPS MORE CONDUCIVE TO
BIGGER SN FLAKES...BEST CHC TO GET THE HIER LES CHART FCST NUMBERS
WOULD BE OVER THE ERN CWA. GOING LES WRNG FOR THIS AREA APPEARS ON
TRACK. IF THE SN BANDS IMPACT SRN SCHOOLCRAFT COUNTY AS SOME OF THE
HIER RES MODELS SHOW...AN ADVY MIGHT BE NECESSARY FOR THAT AREA. BUT
GIVEN UNCERTAINTY ON THIS SCENARIO...HELD OFF FOR NOW. CURRENT
WINTER WX ADVYS OVER THE W ALSO SEEM WELL PLACED. WITH H85 TEMPS
FCST TO FALL AT LEAST CLOSE TO -30C THRU THE DAY...EXPECT SFC TEMPS
OVER MUCH OF THE W TO REMAIN BLO ZERO. ALTHOUGH WIND CHILLS AT MOST
PLACES EXCEPT FOR IWD ARE UNDER ADVY CRITERIA...ARRIVAL OF COLDER
AIR/INCRSG WINDS WITH LLVL DESTABILIZATION JUSTIFIES CONTINUING
ADVYS OVER THE INTERIOR W HALF EVEN IF THERE IS MORE LK MODERATION
WITH VEERING LLVL FLOW. THESE WINDS WL ALSO AID BLSN/REDUCING VSBYS
AND JUSTIFY HEADLINES EVEN IF SN AMOUNTS ARE SUB HEADLINE.
TNGT...WITH DNVA/LARGER SCALE SUBSIDENCE IN THE WAKE OF DEPARTING
SHRTWV THAT BEGINS THIS AFTN...EXPECT CONVECTIVE LYR/MSTR DEPTH TO
SLOWLY SINK. H925 WINDS ARE ALSO FCST TO VEER A BIT MORE TOWARD THE
NW...SO SHSN OVER THE W MIGHT SINK TOWARD IWD. CONSIDERING THE
AGREEMENT ON THE MODELS SHOWING HIER QPF OVER IWD WITH THIS VEERING
FLOW...OPTED TO INCLUDE GOGEBIC COUNTY IN WINTER WX ADVY IN LIEU OF
JUST THE WIND CHILL HEADLINE. ALTHOUGH H85 TEMPS FCST AS LO AS -30C
OVER PORTIONS OF THE W INDICATE WELL BLO ZERO LO TEMPS...TENDED TO
BUMP UP FCST MIN TEMPS A FEW DEGREES WITH MORE LK MODERATION IN
VEERED FLOW. BUT STILL EXPECT WIND CHILLS AS LO AS -25F TO -35F WITH
CAD MAINTAINING SOME MIXING...SO MAINTAINED GOING WIND CHILL ADVYS.
SHARPEST LLVL CNVGC/SOME LK MODERATION OF ARCTIC CHILL REMAINS OVER
THE E. GOING LK EFFECT SN WRNG THRU 12Z TUE IN THAT AREA LOOKS ON
TRACK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 508 AM EST MON JAN 21 2013
AT 12Z TUE...THE COLDEST 850MB TEMPS AS LOW AS -32C WILL BE OVER THE
CWA...BUT WILL PUSH E THROUGH THE DAY AS THE UPPER TROUGH OVER MUCH
OF THE CONUS SHIFTS SLOWLY E. WITH A SFC RIDGE PUSHING IN FROM THE
SW AND A LAKE INDUCED SFC TROUGH STRETCHING INTO ERN LAKE SUPERIOR
FROM THE SE...WINDS WILL BE OUT OF THE NW WITH RESULTING NW WIND
LES. THESE COLD TEMPS WILL KEEP HIGHS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO...BUT WITH THE PRESSURE GRADIENT RELAXING THROUGH THE
DAY...WIND CHILL HEADLINES WILL NOT BE NEEDED AFTER THE MORNING OURS
TUE.
TUE NIGHT WILL BE QUITE COLD WITH LOWS TO -2 OVER MUCH OF INTERIOR
WRN UPPER MI...BUT WINDS WILL BE LIGHT SO AT THIS POINT WIND CHILL
HEADLINES DO NOT APPEAR TO BE NECESSARY. A SHORTWAVE TROUGH WILL
APPROACH THE CWA WED NIGHT AND MOVE THROUGH ON WED...BUT ANY
SYNOPTIC PRECIP WILL REMAIN OUT OF THE CWA. THE SHORTWAVE WILL ACT
TO ENHANCE THE SFC TROUGHING OVER LAKE SUPERIOR /POSSIBLY INTO A
WEAK LOW OVER THE ERN LAKE/...WHICH MODELS INDICATE WOULD CAUSE LOW
LEVEL WINDS TO BECOME MORE WLY AND CYCLONIC OVER MUCH OF LAKE
SUPERIOR. IF THE WINDS DO ALIGN AS INDICATED...A MORE DOMINANT LES
BAND WOULD PROBABLY RESULT OVER THE KEWEENAW AND POSSIBLY INTO THE
FAR NERN CWA /FAR NRN ALGER AND LUCE COUNTIES/. 850MB TEMPS TUE
NIGHT LOOK TO BE IN THE -20C TO -25C RANGE...SO SNOW TO LIQUID
RATIOS SHOULD BE A BIT BETTER THAN WHAT WE HAVE SEEN IN THE LAST DAY
OR SO WITH THE REALLY COLD TEMPS OVER THE CWA. COULD SEE SEVERAL
INCHES OF SNOW IN THE IMPACTED AREAS IF THESE DETAILS COME TOGETHER.
LOW LEVEL WINDS BECOME MORE NWLY ON WED AS THE SHORTWAVE PASSES.
CONDITIONS WILL BE MORE THAN SUFFICIENT FOR MODERATE TO POSSIBLY
HEAVY LES GIVEN LAKE INDUCED EQUILIBRIUM LEVELS OVER 10KFT PER MODEL
SOUNDINGS.
CONDITIONS WILL BECOME INCREASINGLY HOSTILE FOR LES WED NIGHT AS A
SFC RIDGE MOVES IN FROM THE NW...SO WILL HAVE DECREASING POPS INTO
THU. MODELS DISAGREE MORE ON A SHORTWAVE POSSIBLY MOVING S OF THE
CWA THU INTO THU NIGHT...BUT CHANCE POPS NEAR LAKE SUPERIOR AS IS IN
THE GOING FORECAST SEEM REASONABLE SO WILL LEAVE THAT IDEA IN THERE.
850MB TEMPS WARM INTO THE NEGATIVE TEENS BY LATE THU AS THE UPPER
TROUGH PUSHES FARTHER TO THE E. MODELS AGREE WITH BRINGING ANOTHER
SHORTWAVE THROUGH ON FRI...BUT DISAGREE ON THE STRENGTH.
AGAIN...CHANCE POPS AT LEAST IN NW WIND SNOWBELTS SEEMS REASONABLE
FOR FRI. UPPER AND SFC RIDGING PUSHES IN FROM THE W THROUGH THE REST
OF THE FORECAST PERIOD...WITH WARMING LOW LEVEL TEMPS...DECREASING
CHANCES FOR LES AND NO MAJOR SYSTEM EXPECTED TO MOVE THROUGH. SIMPLY
USED A CONSENSUS OF MODELS FOR THIS TIME PERIOD AND FOCUSED MORE ON
THE SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM EST MON JAN 21 2013
KIWD...AS THE LLVL FLOW TENDS TO VEER A BIT WITH PASSAGE OF
DISTURBANCE MOVING THRU THE UPR LKS...EXPECT MORE -SHSN TO IMPACT
THE AREA BY LATER THIS MRNG. SO PREDOMINANT VFR WX SHOULD TRANSITION
TO IFR CONDITIONS AS SMALL SN FLAKES WL EFFICIENTLY REDUCE VSBY.
KCMX...EXPECT PREDOMINANT IFR/LIFR CONDITONS THIS FCST PERIOD WITH
FREQUENT -SHSN/GUSTY NW WINDS/BLSN. SMALL SNOWFLAKES WILL EXACERBATE
THE BLSN AND REDUCED VSBY.
KSAW...EXPECT DOWNSLOPING W TO NW FLOW TO BRING PREDOMINANT VFR
CONDITIONS WITH NOTHING MORE THAN FLURRIES THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EST MON JAN 21 2013
EXPECT NW WINDS 15 TO 30 KT THRU TONIGHT TO ADVECT ARCTIC AIR OVER
THE LAKE AND CAUSE PERIODS OF HEAVY FREEZING SPRAY. LIGHTER WINDS AT
TIMES INTO THIS AFTERNOON NEAR A LO PRES TROF OVER EASTERN LAKE
SUPERIOR MAY BRING A BREAK FROM THE HEAVY FREEZING SPRAY. FREEZING
SPRAY WILL CONTINUE AT TIMES THROUGH WEDNESDAY. NO GALES ARE EXPECTED
THROUGH THE FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR
MIZ001>003-009-084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ004-
005-010-011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
511 AM EST MON JAN 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EST MON JAN 21 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
E AND CENTRAL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF THE W
COAST. COLDEST AIRMASS OF THE SEASON HAS FLOODED INTO THE UPR LKS IN
THE NW LLVL FLOW WITH H85 TEMPS AS LO AS -25C OVER THE WRN CWA. 00Z
H85 TEMP WAS AS LO AS -30C AT YPL. THE PASSAGE OF THIS COLD AIRMASS
OVER THE RELATIVELY WARM WATERS OF LK SUP HAS RESULTED IN NMRS LK
EFFECT SHSN. BUT LLVL FLOW HAS BACKED TO MORE WNW IN ADVANCE OF NEXT
SHRTWV DROPPING SEWD THRU NW ONTARIO TOWARD ISLE ROYALE. IN CONCERT
WITH NEAR SFC WSW WIND ENHANCED BY LAND BREEZE FLOW OF SUB ZERO
TEMPS TOWARD WARMER LK SUP...THIS WSHFT IS CONFINING THE BULK OF THE
LES TO AREAS OVER THE W MAINLY N OF THE PORCUPINE MTNS THRU THE
KEWEENAW AND TO AREAS NEAR LK SUP E OF PICTURED ROCKS LAKESHORE. ONE
IMPACT OF THE VERY COLD AIRMASS IS THE DGZ HAS NEARLY DISAPPEARED AT
LEAST OVER THE W...RESULTING IN VERY FINE SN FLAKES THAT EFFICIENTLY
REDUCE THE VSBY WHILE LIMITING SN ACCUMS. SKIES ARE GENERALLY
CLR-PCLDY OVER AREAS TO THE S OF THE LES...WHICH HAS ALLOWED TEMPS
TO FALL BLO ZERO. THE WIND CHILL EARLY THIS MRNG HAS DROPPED AS LO
AS -25F AT IWD. TO THE NW...THERE IS AN AREA OF CLDS ASSOCIATED WITH
THE DIGGING SHRTWV AND FAIRLY DEEP MSTR DEPICTED ON THE 00Z YPL
RAOB. THERE ARE EVEN SOME REPORTS OF -SN IN ONTARIO JUST N OF THE MN
BORDER DESPITE PWATS OF 0.06 INCH REPORTED AT INL/YPL.
TODAY...AS SHRTWV/ACCOMPANYING DEEP LYR QVECTOR CNVGC/MSTR JUST TO
THE NW DIG SEWD ACROSS THE CWA THIS MRNG...EXPECT LES INTENSITY TO
INCRS SOMEWHAT WHILE NEAR -30C H85 TEMPS ARE DRAWN INTO WRN UPR MI.
ALTHOUGH DEEPENING CONVECTIVE DEPTH/MSTR TO ABV 10K FT AS SHOWN ON
FCST SDNGS WOULD NORMALLY BE A CONCERN FOR VERY HEAVY LES...NEAR
ABSENCE OF DGZ WITH SUCH COLD H85 TEMPS INDICATES SN FLAKES WL BE
VERY SMALL...ESPECIALLY OVER THE W WITH SHORTER FETCH/LESS
MODIFICATION OF THE COLD/DRY AIRMASS. ONE ADVANTAGE FOR HEAVIER SHSN
WOULD BE INCRSG LLVL CNVGC. SINCE THE LLVL FLOW WL VEER MORE TO THE
NW WITH PASSAGE OF SHRTWV...EXPECT LES BANDS TO DRIFT BACK TO THE S.
THIS VEERING FLOW OFF THE SFC WL LIKELY RESULT IN SHARPER LLVL CNVGC
OVER THE W BTWN LAND BREEZE FLOWS OFF WI/INTERIOR WRN UPR MI AND
OVER THE E WITH THESE FLOWS OFF CNTRL UPR MI AND SE ONTARIO/ERN UPR
MI. GENERAL CONSENSUS OF HIER RES MODELS SHOWS THE BACK CHC FOR THE
SHARPER CNVGC WL BE OVER THE W FM THE PORCUPINE MTNS TO NEAR TWIN
LAKES IN CNTRL HOUGHTON COUNTY AND IN AREAS E OF MUNISING AND AS FAR
S AS ABOUT HIGHWAY M-28. THESE HI RES MODELS ALL SHOW THE SHARPEST
CNVGC/HIER QPF OVER THE ERN CWA...AND SOME INDICATE THE HEAVIER SHSN
WL PUSH FARTHER INLAND THAN M-28. ON THE OTHER HAND...SOME OF THE
MODELS INDICATE A LK INDUCED VORTEX MAY DVLP NEAR GRAND MARAIS AND
LIMIT THE INLAND SPREAD OF THE SHSN. AS FOR SN AMOUNTS...OLD LES
CHART INDICATES SN FALL OF 5-9 INCHES/12 HRS GIVEN EXPECTED
CONDITIONS. BUT RECENT EXPERIENCE SUGS THE NEAR ABSENCE OF DGZ CUTS
THESE TOTALS BY ABOUT HALF. WITH SHARPER LLVL CNVGC/MORE LK
MODERATION THAT WOULD MAINTAIN HIER LLVL TEMPS MORE CONDUCIVE TO
BIGGER SN FLAKES...BEST CHC TO GET THE HIER LES CHART FCST NUMBERS
WOULD BE OVER THE ERN CWA. GOING LES WRNG FOR THIS AREA APPEARS ON
TRACK. IF THE SN BANDS IMPACT SRN SCHOOLCRAFT COUNTY AS SOME OF THE
HIER RES MODELS SHOW...AN ADVY MIGHT BE NECESSARY FOR THAT AREA. BUT
GIVEN UNCERTAINTY ON THIS SCENARIO...HELD OFF FOR NOW. CURRENT
WINTER WX ADVYS OVER THE W ALSO SEEM WELL PLACED. WITH H85 TEMPS
FCST TO FALL AT LEAST CLOSE TO -30C THRU THE DAY...EXPECT SFC TEMPS
OVER MUCH OF THE W TO REMAIN BLO ZERO. ALTHOUGH WIND CHILLS AT MOST
PLACES EXCEPT FOR IWD ARE UNDER ADVY CRITERIA...ARRIVAL OF COLDER
AIR/INCRSG WINDS WITH LLVL DESTABILIZATION JUSTIFIES CONTINUING
ADVYS OVER THE INTERIOR W HALF EVEN IF THERE IS MORE LK MODERATION
WITH VEERING LLVL FLOW. THESE WINDS WL ALSO AID BLSN/REDUCING VSBYS
AND JUSTIFY HEADLINES EVEN IF SN AMOUNTS ARE SUB HEADLINE.
TNGT...WITH DNVA/LARGER SCALE SUBSIDENCE IN THE WAKE OF DEPARTING
SHRTWV THAT BEGINS THIS AFTN...EXPECT CONVECTIVE LYR/MSTR DEPTH TO
SLOWLY SINK. H925 WINDS ARE ALSO FCST TO VEER A BIT MORE TOWARD THE
NW...SO SHSN OVER THE W MIGHT SINK TOWARD IWD. CONSIDERING THE
AGREEMENT ON THE MODELS SHOWING HIER QPF OVER IWD WITH THIS VEERING
FLOW...OPTED TO INCLUDE GOGEBIC COUNTY IN WINTER WX ADVY IN LIEU OF
JUST THE WIND CHILL HEADLINE. ALTHOUGH H85 TEMPS FCST AS LO AS -30C
OVER PORTIONS OF THE W INDICATE WELL BLO ZERO LO TEMPS...TENDED TO
BUMP UP FCST MIN TEMPS A FEW DEGREES WITH MORE LK MODERATION IN
VEERED FLOW. BUT STILL EXPECT WIND CHILLS AS LO AS -25F TO -35F WITH
CAD MAINTAINING SOME MIXING...SO MAINTAINED GOING WIND CHILL ADVYS.
SHARPEST LLVL CNVGC/SOME LK MODERATION OF ARCTIC CHILL REMAINS OVER
THE E. GOING LK EFFECT SN WRNG THRU 12Z TUE IN THAT AREA LOOKS ON
TRACK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 508 AM EST MON JAN 21 2013
AT 12Z TUE...THE COLDEST 850MB TEMPS AS LOW AS -32C WILL BE OVER THE
CWA...BUT WILL PUSH E THROUGH THE DAY AS THE UPPER TROUGH OVER MUCH
OF THE CONUS SHIFTS SLOWLY E. WITH A SFC RIDGE PUSHING IN FROM THE
SW AND A LAKE INDUCED SFC TROUGH STRETCHING INTO ERN LAKE SUPERIOR
FROM THE SE...WINDS WILL BE OUT OF THE NW WITH RESULTING NW WIND
LES. THESE COLD TEMPS WILL KEEP HIGHS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO...BUT WITH THE PRESSURE GRADIENT RELAXING THROUGH THE
DAY...WIND CHILL HEADLINES WILL NOT BE NEEDED AFTER THE MORNING OURS
TUE.
TUE NIGHT WILL BE QUITE COLD WITH LOWS TO -2 OVER MUCH OF INTERIOR
WRN UPPER MI...BUT WINDS WILL BE LIGHT SO AT THIS POINT WIND CHILL
HEADLINES DO NOT APPEAR TO BE NECESSARY. A SHORTWAVE TROUGH WILL
APPROACH THE CWA WED NIGHT AND MOVE THROUGH ON WED...BUT ANY
SYNOPTIC PRECIP WILL REMAIN OUT OF THE CWA. THE SHORTWAVE WILL ACT
TO ENHANCE THE SFC TROUGHING OVER LAKE SUPERIOR /POSSIBLY INTO A
WEAK LOW OVER THE ERN LAKE/...WHICH MODELS INDICATE WOULD CAUSE LOW
LEVEL WINDS TO BECOME MORE WLY AND CYCLONIC OVER MUCH OF LAKE
SUPERIOR. IF THE WINDS DO ALIGN AS INDICATED...A MORE DOMINANT LES
BAND WOULD PROBABLY RESULT OVER THE KEWEENAW AND POSSIBLY INTO THE
FAR NERN CWA /FAR NRN ALGER AND LUCE COUNTIES/. 850MB TEMPS TUE
NIGHT LOOK TO BE IN THE -20C TO -25C RANGE...SO SNOW TO LIQUID
RATIOS SHOULD BE A BIT BETTER THAN WHAT WE HAVE SEEN IN THE LAST DAY
OR SO WITH THE REALLY COLD TEMPS OVER THE CWA. COULD SEE SEVERAL
INCHES OF SNOW IN THE IMPACTED AREAS IF THESE DETAILS COME TOGETHER.
LOW LEVEL WINDS BECOME MORE NWLY ON WED AS THE SHORTWAVE PASSES.
CONDITIONS WILL BE MORE THAN SUFFICIENT FOR MODERATE TO POSSIBLY
HEAVY LES GIVEN LAKE INDUCED EQUILIBRIUM LEVELS OVER 10KFT PER MODEL
SOUNDINGS.
CONDITIONS WILL BECOME INCREASINGLY HOSTILE FOR LES WED NIGHT AS A
SFC RIDGE MOVES IN FROM THE NW...SO WILL HAVE DECREASING POPS INTO
THU. MODELS DISAGREE MORE ON A SHORTWAVE POSSIBLY MOVING S OF THE
CWA THU INTO THU NIGHT...BUT CHANCE POPS NEAR LAKE SUPERIOR AS IS IN
THE GOING FORECAST SEEM REASONABLE SO WILL LEAVE THAT IDEA IN THERE.
850MB TEMPS WARM INTO THE NEGATIVE TEENS BY LATE THU AS THE UPPER
TROUGH PUSHES FARTHER TO THE E. MODELS AGREE WITH BRINGING ANOTHER
SHORTWAVE THROUGH ON FRI...BUT DISAGREE ON THE STRENGTH.
AGAIN...CHANCE POPS AT LEAST IN NW WIND SNOWBELTS SEEMS REASONABLE
FOR FRI. UPPER AND SFC RIDGING PUSHES IN FROM THE W THROUGH THE REST
OF THE FORECAST PERIOD...WITH WARMING LOW LEVEL TEMPS...DECREASING
CHANCES FOR LES AND NO MAJOR SYSTEM EXPECTED TO MOVE THROUGH. SIMPLY
USED A CONSENSUS OF MODELS FOR THIS TIME PERIOD AND FOCUSED MORE ON
THE SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1233 AM EST MON JAN 21 2013
KIWD...WSW FLOW WILL VEER WNW LATE TONIGHT AND SHOULD BRING SOME
MVFR CIGS IN LIGHT LAKE EFFECT SNOW. SOME GUSTIER WINDS MONDAY
SHOULD CONTRIBUTE TO IFR CONDITIONS BY LATE MORNING WHICH WILL
LIKELY PERSIST INTO THE EVENING.
KCMX...LAKE EFFECT SNOW SHOWERS WITH FINE SNOWFLAKES WILL CONTRIBUTE
TO BLOWING SNOW AND SHARPLY REDUCED VSBYS THROUGH THE TAF PD WITH
PREVAILING LIFR CONDITIONS.
KSAW...WEST FLOW VEERING NORTHWEST ON MONDAY MORNING WILL ALLOW VFR
CONDITIONS TO TURN TO MVFR AS SOME LAKE CLOUDS AND OCCASIONAL
FLURRIES MOVE INTO THE AREA. VSBY COULD EVEN OCCASIONALLY LOWER TO
MVFR IN LIGHT -SHSN DURING THE DAY ON MONDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EST MON JAN 21 2013
EXPECT NW WINDS 15 TO 30 KT THRU TONIGHT TO ADVECT ARCTIC AIR OVER
THE LAKE AND CAUSE PERIODS OF HEAVY FREEZING SPRAY. LIGHTER WINDS AT
TIMES INTO THIS AFTERNOON NEAR A LO PRES TROF OVER EASTERN LAKE
SUPERIOR MAY BRING A BREAK FROM THE HEAVY FREEZING SPRAY. FREEZING
SPRAY WILL CONTINUE AT TIMES THROUGH WEDNESDAY. NO GALES ARE EXPECTED
THROUGH THE FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR
MIZ001>003-009-084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ004-
005-010-011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
248 AM PST MON JAN 21 2013
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE WILL REMAIN OVER THE WESTERN
UNITED STATES TODAY...SLOWLY WEAKENING AND MOVING EAST TONIGHT AND
TUESDAY. HOWEVER A STRONG INVERSION WILL REMAIN IN PLACE THROUGH
TUESDAY...WITH STUBBORN FOG...LOW CLOUDS AND POOR AIR QUALITY BELOW
THE INVERSION. EAST WINDS COMING FROM THE COLUMBIA RIVER GORGE WILL
DISRUPT THE FOG IN PARTS OF THE PORTLAND AND VANCOUVER METRO AREAS AT
TIMES THROUGH TUESDAY. AREAS FROM AROUND SALEM SOUTHWARD WILL REMAIN
GENERALLY CLOUDY AND STUCK NEAR FREEZING THROUGH TUESDAY. A PATTERN
CHANGE IS EXPECTED BY MIDWEEK WHICH WILL BRING SOME RAIN TO THE
DISTRICT...WHICH MAY START OFF AS A LITTLE ICE OR SNOW INLAND...
ESPECIALLY IN AND NEAR THE COLUMBIA GORGE.
&&
.SHORT TERM...OFFSHORE SURFACE PRESSURE GRADIENTS CONTINUE QUITE
STRONG THIS MORNING AT 8 MB FROM KTTD TO KDLS...DOWN SLIGHTLY FROM
THE PEAK OF 10 MB LATE SUNDAY. THE OFFSHORE GRADIENT IS EXPECTED TO
REMAIN QUITE STRONG THROUGH TODAY AND TONIGHT AND TUESDAY. WITH THE
STRONG WARM UPPER RIDGE OVER THE AREA...A STRONG LOW LEVEL
TEMPERATURE INVERSION WILL CONTINUE INTO TUESDAY OVER THE AREA...
TRAPPING PERSISTENT FOG AND POLLUTANTS BELOW THE INVERSION. FOG AND
FREEZING FOG WILL BE PERSISTENT IN THE CENTRAL AND SOUTH WILLAMETTE
VALLEY...AND POSSIBLY FROM LONGVIEW NORTHWARD ALONG I5. HOWEVER...
THE STRONG EAST WINDS THROUGH THE GORGE INTO THE TROUTDALE AREA WILL
KEEP THE AREA NEAR TROUTDALE CLEAR...AND MAY CONTINUE TO DISRUPT ITS
FORMATION AND MAINTENANCE IN THE PORTLAND/VANCOUVER METRO AREAS AWAY
FROM THE GORGE. SOME FOG SHOULD DEVELOP AWAY FROM THE GORGE...BUT
EXPECT CLEARING THIS AFTERNOON SIMILAR TO THAT ON SUNDAY. REALLY DO
NOT SEE ANYTHING OTHER THAN SUBTLE CHANGES FROM THIS SCENARIO ON
TUESDAY.
COLD AIR AND STRATUS IS ALSO ENTRENCHED EAST OF THE CASCADES IN THE
COLUMBIA BASIN...AND THIS WILL KEEP THE UPPER HOOD RIVER VALLEY AND
THE PORTION OF THE COLUMBIA RIVER GORGE NEAR HOOD RIVER IN THE CLOUDS
TODAY AND TUESDAY. TEMPS WILL HAVE TROUBLE EXCEEDING FREEZING IN
THOSE AREAS.
THE MODELS SHOW GOOD AGREEMENT ON THE UPPER RIDGE WEAKENING AND
MOVING EAST ON TUESDAY AS THE NEXT PACIFIC FRONT APPROACHES FROM THE
WEST. MODEL CONSENSUS IS SLOWING DOWN THE ARRIVAL OF THIS FRONT UNTIL
TUESDAY NIGHT AND WEDNESDAY...AND ESPECIALLY LATE TUESDAY NIGHT AND
DURING THE DAY WEDNESDAY. WE WILL CONTINUE TO HAVE A COLD LOW LEVEL
AIR MASS OVER THE AREA AS THIS FRONT INITIALLY SPREADS ONSHORE...
WHICH COULD LEAD TO A MIX OF WINTER PRECIPITATION ESPECIALLY IN THE
GORGE BUT EVEN BRIEFLY IN THE INLAND VALLEYS AS THE PREFRONTAL
SURFACE GRADIENT REMAINS EASTERLY. THE PRECIPITATION SHOULD SWITCH
OVER TO RAIN FAIRLY RAPIDLY IN THE VALLEYS ON WEDNESDAY AS THE LOW
LEVEL FLOW TURNS ONSHORE. BECAUSE OF THE RELATIVELY SLOW MOVEMENT OF
THE FRONT...IT MAY TAKE UNTIL WEDNESDAY AFTERNOON BEFORE THE WINTER
PRECIPITATION MODERATES IN THE GORGE. THIS FRONT MOVING THROUGH WILL
FINALLY BRING AN END TO OUR CURRENT PERIOD OF AIR STAGNATION.
TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
WEDNESDAY EVENING THROUGH SUNDAY MORNING...SHOWERS ARE EXPECTED TO
CONTINUE LATE WEDNESDAY NIGHT INTO EARLY THURSDAY AS A QUICK MOVING
TROUGH CONTINUES ON EASTWARD. MODELS THEN REBUILD THE RIDGE FOR
THURSDAY...WITH DECREASING SHOWER POTENTIAL. A SYSTEM WHICH RIDES
OVER THE TOP OF THE RIDGE MAY BRING LIGHT PRECIPITATION TO THE AREA
LATE THURSDAY INTO FRIDAY...ESPECIALLY THE NORTHERN HALF OF THE
FORECAST AREA. MODELS CONTINUE TO TRY TO COME TO SOME AGREEMENT ON A
SYSTEM BREAKING DOWN THE RIDGE AND SWINGING A FRONTAL SYSTEM THROUGH
THE AREA OVER THE WEEKEND...THOUGH DETAILS ARE NOT WELL AGREED UPON
AT THIS POINT. HAVE LEFT A VERY CLIMATOLOGICAL FORECAST IN FOR THE
WEEKEND. BROWN
&&
.AVIATION...A SURFACE TROUGH APPEARS TO BE ORIENTED PARALLEL TO THE
COAST ABOUT 30 MILES OFFSHORE. LOWER RESOLUTION MODELS GENERALLY
DEPICT THIS BOUNDARY RETREATING OFFSHORE OVER THE NEXT 12 HRS.
HOWEVER...SATELLITE TRENDS SUGGEST OTHERWISE THIS MORNING.
INTERESTINGLY...THE HRRR MODEL TRIES TO PUSH THIS LINE OF LOW CLOUDS
AND LIGHT SOUTHWESTERLY WINDS TO THE COAST BY LATE THIS MORNING...
PARTICULARLY ALONG THE NORTH OREGON COAST. SUSPECT KAST WILL STAY
VFR...BUT WILL MONITOR TRENDS IN CASE THE HRRR IS ONTO SOMETHING.
OTHERWISE...LIFR FOG THIS MORNING ACROSS THE INTERIOR VALLEYS WILL
LIKELY BURN OFF IN A SIMILAR PATTERN TO SATURDAY WITH KSLE AND KEUG
LIKELY ONLY EXPERIENCING MARGINAL IMPROVEMENTS TO HIGH END IFR
CONDITIONS IN THE AFTERNOON. LIFR FOG SHOULD RETURN MONDAY NIGHT
EXCEPT NEAR THE MOUTH OF THE COLUMBIA RIVER GORGE WHERE EAST WINDS
WILL CONTINUE TO BLOW AT 20 TO 35 KTS. MAY SEE A SLIGHT TENDENCY FOR
WINDS COMING OUT OF THE COLUMBIA GORGE TO PEAK IN THE LATE AFTERNOON
AND EVENING HOURS RATHER THAN THE EARLY MORNING HOURS OVER THE NEXT
36 HOURS DUE TO DIFFERENTIAL SURFACE HEATING ACROSS THE CASCADES.
KPDX AND APPROACHES...PRESSURE GRADIENTS CONTINUE TO SUPPORT THE
NOTION OF KPDX DECOUPLING ENOUGH FOR LIFR FOG TO DEVELOP EARLY THIS
MORNING. HOWEVER...TEMPERATURES AT THE SENSORS ON THE I5 AND I205
BRIDGES INDICATE EASTERLY FLOW IS STILL IMPACTING AREAS JUST OFF THE
SURFACE AROUND KPDX. FOG HAS CREPT NORTHWARD INTO DOWNTOWN AND
PORTIONS OF I205 THOUGH. STILL DECENTLY CONFIDENT THAT THIS FOG WILL
LIKELY PUSH IN AND DEVELOP AROUND KPDX IN THE NEXT COUPLE OF HOURS AS
FURTHER DECOUPLING OCCURS. DUE TO THE SHALLOW NATURE OF THE FOG AND
NEARBY EAST WINDS...EXPECT CONDITIONS TO IMPROVE QUICKLY LATE THIS
MORNING. FOG FORMATION WILL LIKELY BE SLOW TO OCCUR TONIGHT AS EAST
WINDS CONTINUE TO CRANK JUST OFF THE SURFACE. /NEUMAN
&&
.MARINE...RELATIVELY LIGHT WINDS WILL CONTINUE OVER THE COASTAL
WATERS THROUGH TONIGHT. SMALL CRAFT ADVISORY LEVEL WINDS LOOK LIKELY
FOR TUESDAY AFTERNOON AND TUESDAY NIGHT BEFORE FRONTAL PASSAGE CAUSES
WINDS TO TURN MORE WESTERLY AND DECREASE. ANOTHER WEAK STORM SYSTEM
MAY INCREASE WINDS INTO SMALL CRAFT CRITERIA LATE IN THE WORK WEEK AS
WELL.
LONG PERIOD SWELL WILL CONTINUE TO DECREASE OVER THE NEXT 24 HOURS
BEFORE SEAS BEGIN TO INCREASE TUESDAY AFTERNOON. SEAS SHOULD TOP OUT
IN THE LOW TEENS WEDNESDAY. EXPECT PERIODS TO ONCE AGAIN BE ON THE
HIGHER SIDE OF NORMAL...NEAR 20 SECONDS...AT LEAST INITIALLY WITH
THIS NEXT SWELL TRAIN. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 6 PM PST TUESDAY FOR CENTRAL
WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-LOWER
COLUMBIA-SOUTH WILLAMETTE VALLEY.
WA...AIR STAGNATION ADVISORY UNTIL 6 PM PST TUESDAY FOR GREATER
VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY-SOUTH
WASHINGTON CASCADE FOOTHILLS-WILLAPA HILLS.
PZ...NONE.
&&
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 6 PM PST TUESDAY FOR CENTRAL
WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-LOWER
COLUMBIA-SOUTH WILLAMETTE VALLEY.
WA...AIR STAGNATION ADVISORY UNTIL 6 PM PST TUESDAY FOR GREATER
VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY-SOUTH
WASHINGTON CASCADE FOOTHILLS-WILLAPA HILLS.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
511 AM CST MON JAN 21 2013
.AVIATION...
VFR CONDITIONS MAY BRIEFLY BE INTERRUPTED AT LBB AFTER SUNRISE AS
LOW CLOUDS ATTEMPT TO EXPAND SOUTHEAST FROM EAST OF CLOVIS. FOR NOW
HAVE KEPT THE PREVIOUS TEMPO SCT010 TO ADDRESS THIS SCENARIO AS
CONFIDENCE IN ANY PROLONGED WINDOW OF MVFR/IFR STRATUS IS VERY
LOW. OTHERWISE...EXPECT LIGHT NELY WINDS TO VEER SELY BY LATE DAY
BEHIND COOL HIGH PRESSURE.
&&
.PREV DISCUSSION... /ISSUED 444 AM CST MON JAN 21 2013/
SHORT TERM...
TROUBLE-FREE FROPA OVERNIGHT MAY PROVE MORE COMPLICATED IN THE
COMING HOURS WITHIN THE POST-FRONTAL REGIME. SPECIFICALLY...A
SHALLOW FRONTAL INVERSION WAS SLOWLY MOISTENING IN THE WRN TX
PANHANDLE AS EVIDENCE BY SPOTTY LOW CLOUDS EMERGING ON THE 11-3.9
IR CHANNEL. THIS TRAPPED LAYER OF MOISTURE CONTINUES TO BE
OVERDONE BY THE GFS...WHEREAS THE NAM APPEARS CLOSER TO REALITY.
THE HRRR MEANWHILE IS STILL BEHIND THE CURVE AS IT STRUGGLES TO
CAPTURE THE STRATUS BANK ANCHORED FARTHER NORTH IN THE COMANCHE
NAT`L GRASSLAND.
PATTERN RECOGNITION IN SUCH SETUPS TENDS TO FAVOR AN INCREASE IN
STRATUS /PARTICULARLY AROUND SUNRISE/ AS DEWPOINT DEPRESSIONS ARE
AT THEIR LOWEST. EVEN WITH DRIER 2M DEWPOINTS USHERING ACROSS THE
TX PANHANDLE...THE CRITICAL CLOUD LAYER IS ABOUT 1K FEET ALOFT
ALONG THE FRONTAL INVERSION AND FAR REMOVED FROM THE SHALLOW DRY
AIR BELOW. THE 00Z AND 06Z NAM RUNS SUPPORT THIS IDEA OF
INCREASING STRATUS BY 12-15Z...SO HAVE RAMPED UP CLOUD COVER ON
THE CAPROCK THRU 15Z BEFORE SCATTERING OUT THEREAFTER.
EVEN IF LOW CLOUDS FAIL TO MATERIALIZE...BELIEVE HI TEMPS WILL BE
STUNTED MORE THAN MODELS ADVERTISE AS THE 850MB THERMAL TROUGH
WILL BE SITUATED DIRECTLY OVER THE CWA BY PEAK HEATING COINCIDENT
WITH A SURFACE PRESSURE RIDGE. LACK OF SWLY WINDS AND DEEPER
MIXING IN THIS SETUP DOESN`T BODE WELL FOR TOO MUCH OF DIURNAL
TEMP CURVE...SO HAVE UNDERCUT MOS GUIDANCE MOST PLACES ESPECIALLY
OFF THE CAPROCK WHERE NELY WINDS PREVAIL MOST OF THE AFTERNOON.
LONG TERM...
TEMPERATURES WILL RAPIDLY WARM UP FOR TUESDAY AND WEDNESDAY.
THURSDAY REMAINS PROBLEMATIC AS THE GFS REMAINS INSISTENT ON
BRINGING ANOTHER FRONT INTO THE NORTHEASTERN HALF OF THE FORECAST
AREA BEFORE STALLING IT OUT. ALL OTHER NWP GUIDANCE INDICATES THE
FRONT TO STALL OUT WELL NORTH OF THE REGION WITH WESTERLY FLOW
THROUGH THE DAY THURSDAY. BECAUSE OF THESE DIFFERENCES...SOME
LOCATIONS HAVE BEEN GIVEN HIGH TEMPERATURES ON THURSDAY ANYWHERE
FROM THE LOW 60S TO UPPER 70S. WITH THE TREND IN MOST OF THE
MODELS TO BE WESTERLY SURFACE WIND DEVELOPING THROUGH THE
DAY...INCREASED TEMPERATURES FROM PREVIOUS FORECAST A BIT BUT DID
NOT GO QUITE AS HIGH AS THE NAM IS PREDICTING. THE GFS IS STILL
TRYING TO DEVELOP PRECIPITATION WITH THE FRONTAL PASSAGE BUT THIS
APPEARS TO BE OVERDONE AS THIS MODEL HAS SURFACE MOISTURE POOLING
ALONG THE FRONT WHILE ALL OTHER MODELS DO NOT REFLECT THIS
ALSO CAN SEE SOME ISSUES ON FRIDAY DEPENDING ON WHETHER THE FRONT
IS ALREADY THROUGH THE REGION SUCH AS THE ECMWF OR CANADIAN ARE
SHOWING...OR WHETHER IT PUSHES THROUGH DURING THE DAY ON FRIDAY AS
THE GFS IS SHOWING. TEMPERATURES WILL START TO WARM FOR THE
UPCOMING WEEKEND AS SOUTHERLY FLOW RAPIDLY DEVELOPS AT THE SURFACE
ACROSS THE REGION AND SOUTHWESTERLY FLOW ALOFT HELPS TO DEVELOP
THE LEE SURFACE TROF ONCE AGAIN.
JORDAN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 45 24 62 28 68 / 0 0 0 0 0
TULIA 44 24 63 30 68 / 0 0 0 0 0
PLAINVIEW 45 25 63 30 68 / 0 0 0 0 0
LEVELLAND 48 26 63 30 69 / 0 0 0 0 0
LUBBOCK 46 26 62 31 68 / 0 0 0 0 0
DENVER CITY 49 30 63 34 69 / 0 0 0 0 0
BROWNFIELD 48 28 63 34 71 / 0 0 0 0 0
CHILDRESS 44 27 62 33 68 / 0 0 0 0 0
SPUR 44 28 63 39 71 / 0 0 0 0 0
ASPERMONT 45 30 65 41 72 / 0 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
444 AM CST MON JAN 21 2013
.SHORT TERM...
TROUBLE-FREE FROPA OVERNIGHT MAY PROVE MORE COMPLICATED IN THE
COMING HOURS WITHIN THE POST-FRONTAL REGIME. SPECIFICALLY...A
SHALLOW FRONTAL INVERSION WAS SLOWLY MOISTENING IN THE WRN TX
PANHANDLE AS EVIDENCE BY SPOTTY LOW CLOUDS EMERGING ON THE 11-3.9
IR CHANNEL. THIS TRAPPED LAYER OF MOISTURE CONTINUES TO BE
OVERDONE BY THE GFS...WHEREAS THE NAM APPEARS CLOSER TO REALITY.
THE HRRR MEANWHILE IS STILL BEHIND THE CURVE AS IT STRUGGLES TO
CAPTURE THE STRATUS BANK ANCHORED FARTHER NORTH IN THE COMANCHE
NAT`L GRASSLAND.
PATTERN RECOGNITION IN SUCH SETUPS TENDS TO FAVOR AN INCREASE IN
STRATUS /PARTICULARLY AROUND SUNRISE/ AS DEWPOINT DEPRESSIONS ARE
AT THEIR LOWEST. EVEN WITH DRIER 2M DEWPOINTS USHERING ACROSS THE
TX PANHANDLE...THE CRITICAL CLOUD LAYER IS ABOUT 1K FEET ALOFT
ALONG THE FRONTAL INVERSION AND FAR REMOVED FROM THE SHALLOW DRY
AIR BELOW. THE 00Z AND 06Z NAM RUNS SUPPORT THIS IDEA OF
INCREASING STRATUS BY 12-15Z...SO HAVE RAMPED UP CLOUD COVER ON
THE CAPROCK THRU 15Z BEFORE SCATTERING OUT THEREAFTER.
EVEN IF LOW CLOUDS FAIL TO MATERIALIZE...BELIEVE HI TEMPS WILL BE
STUNTED MORE THAN MODELS ADVERTISE AS THE 850MB THERMAL TROUGH
WILL BE SITUATED DIRECTLY OVER THE CWA BY PEAK HEATING COINCIDENT
WITH A SURFACE PRESSURE RIDGE. LACK OF SWLY WINDS AND DEEPER
MIXING IN THIS SETUP DOESN`T BODE WELL FOR TOO MUCH OF DIURNAL
TEMP CURVE...SO HAVE UNDERCUT MOS GUIDANCE MOST PLACES ESPECIALLY
OFF THE CAPROCK WHERE NELY WINDS PREVAIL MOST OF THE AFTERNOON.
&&
.LONG TERM...
TEMPERATURES WILL RAPIDLY WARM UP FOR TUESDAY AND WEDNESDAY.
THURSDAY REMAINS PROBLEMATIC AS THE GFS REMAINS INSISTENT ON
BRINGING ANOTHER FRONT INTO THE NORTHEASTERN HALF OF THE FORECAST
AREA BEFORE STALLING IT OUT. ALL OTHER NWP GUIDANCE INDICATES THE
FRONT TO STALL OUT WELL NORTH OF THE REGION WITH WESTERLY FLOW
THROUGH THE DAY THURSDAY. BECAUSE OF THESE DIFFERENCES...SOME
LOCATIONS HAVE BEEN GIVEN HIGH TEMPERATURES ON THURSDAY ANYWHERE
FROM THE LOW 60S TO UPPER 70S. WITH THE TREND IN MOST OF THE
MODELS TO BE WESTERLY SURFACE WIND DEVELOPING THROUGH THE
DAY...INCREASED TEMPERATURES FROM PREVIOUS FORECAST A BIT BUT DID
NOT GO QUITE AS HIGH AS THE NAM IS PREDICTING. THE GFS IS STILL
TRYING TO DEVELOP PRECIPITATION WITH THE FRONTAL PASSAGE BUT THIS
APPEARS TO BE OVERDONE AS THIS MODEL HAS SURFACE MOISTURE POOLING
ALONG THE FRONT WHILE ALL OTHER MODELS DO NOT REFLECT THIS
ALSO CAN SEE SOME ISSUES ON FRIDAY DEPENDING ON WHETHER THE FRONT
IS ALREADY THROUGH THE REGION SUCH AS THE ECMWF OR CANADIAN ARE
SHOWING...OR WHETHER IT PUSHES THROUGH DURING THE DAY ON FRIDAY AS
THE GFS IS SHOWING. TEMPERATURES WILL START TO WARM FOR THE
UPCOMING WEEKEND AS SOUTHERLY FLOW RAPIDLY DEVELOPS AT THE SURFACE
ACROSS THE REGION AND SOUTHWESTERLY FLOW ALOFT HELPS TO DEVELOP
THE LEE SURFACE TROF ONCE AGAIN.
JORDAN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 45 24 62 28 68 / 0 0 0 0 0
TULIA 44 24 63 30 68 / 0 0 0 0 0
PLAINVIEW 45 25 63 30 68 / 0 0 0 0 0
LEVELLAND 48 26 63 30 69 / 0 0 0 0 0
LUBBOCK 46 26 62 31 68 / 0 0 0 0 0
DENVER CITY 49 30 63 34 69 / 0 0 0 0 0
BROWNFIELD 48 28 63 34 71 / 0 0 0 0 0
CHILDRESS 44 27 62 33 68 / 0 0 0 0 0
SPUR 44 28 63 39 71 / 0 0 0 0 0
ASPERMONT 45 30 65 41 72 / 0 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
521 AM CST MON JAN 21 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
306 AM CST MON JAN 21 2013
THE CONTINUED FOCUS REMAINS ON THE BITTERLY COLD AIR MASS THAT HAS
HUNKERED DOWN ACROSS THE REGION AND WILL LINGER THROUGH THE NEXT
FEW DAYS.
BROAD CYCLONIC FLOW ALOFT REMAINS ENTRENCHED ACROSS THE REGION AS
THE POLAR VORTEX HAS DRIFTED INTO SOUTHEAST CANADA. AS SHORT WAVE
TROUGHS HAVE PROPAGATED ALONG THE WESTERN PERIPHERY OF THIS
TROUGH...THEY HAVE BROUGHT REINFORCING SHOTS OF COLD AIR ON DOWN
WITH THEM. THE LATEST SHORT WAVE CAME THROUGH EARLY THIS MORNING
AS NOTED ON WATER VAPOR IR. AHEAD OF THIS TROUGH...A COLD FRONT
ALSO MOVED INTO THE REGION WHICH BROUGHT SOME FLURRIES AND SNOW
SHOWERS IN AS WELL. BEHIND THIS FRONT...SKIES CLEAR OUT AND
TEMPERATURES DROP BELOW ZERO. A STRENGTHENING PRESSURE GRADIENT
ALSO HELPED TO INCREASE THE SURFACE WINDS AND TO DROP WIND CHILLS
DOWN INTO THE ADVISORY LEVELS. AS THIS COLDER AIR MASS SHIFTS TO
THE SOUTHEAST THIS MORNING THESE LOWER WIND CHILLS WILL ALSO START
TO OCCUR AT SITES IN NORTHEAST IOWA AND WESTERN WISCONSIN THAT
HAVE BEEN IN THE -5 TO -15F RANGE SO FAR.
HAD THERE BEEN ANY SNOW COVER ON THE GROUND...TEMPERATURES
PROBABLY WOULD NOT MAKE IT ABOVE ZERO TODAY. FORTUNATELY...THE
SNOW PACK MELTED AWAY LAST WEEK AND THE LATEST NOHRSC SNOW DEPTH
ANALYSIS AND LOCAL COOP OBSERVERS SHOWS MOSTLY ZERO SNOW COVER
OUTSIDE OF A FEW SPORADIC 1-3 INCH REPORTS. EVEN WITHOUT THE SNOW
COVER...TEMPERATURES ARE GOING TO REMAIN COLD AS THE CORE OF THE
COLD AIR MASS DROPS DOWN ACROSS THE REGION. 850MB TEMPERATURES
WILL STICK AROUND -25C FOR MOST OF THE AREA WITH THE COLDEST
POCKET OF AIR RUNNING FROM NORTHEAST MINNESOTA INTO NORTH CENTRAL
WISCONSIN. WIND CHILLS SHOULD STAY NEAR OR BELOW -20F THROUGH THE
DAY...SO WILL NOT MAKE ANY CHANGES TO THE WIND CHILL ADVISORY.
21.06Z RAP SOUNDINGS SHOW THAT THERE COULD BE SOME CU THAT FORMS
EAST OF THE RIVER TODAY...SO CAN NOT RULE OUT SOME FLURRIES THERE
AS WELL. BASICALLY...IF WE GET ANY LOW LEVEL CLOUD COVER OVER THE
NEXT FEW DAYS...THERE WILL LIKELY BE SOME FLURRIES OR SNOW SHOWERS
THAT ACCOMPANY IT WITH THE LOW LEVEL TEMPERATURE PROFILE BELOW
-20C. AT THESE TEMPERATURES...WOULD MAINLY EXPECT THE SNOWFLAKES
TO BE PLATES AND COLUMNS AND NOT AMASS TO MUCH IF ANYTHING.
TEMPERATURES WILL START TO IMPROVE ON TUESDAY AS THE BROAD UPPER
TROUGH SHIFTS EAST AND THE CORE OF THE SURFACE RIDGE MOVES ACROSS
THE REGION WITH LOW LEVEL WINDS COMING AROUND TO THE SOUTHWEST.
WILL HAVE TO KEEP AN EYE ON TUESDAY NIGHT INTO WEDNESDAY FOR THE
POTENTIAL OF SOME WARM AIR ADVECTION SNOW. THE 21.00Z NAM IS A BIT
STRONGER WITH THE LOW LEVEL LIFT AND SATURATION COMPARED TO THE
REST OF THE GUIDANCE. HAVE KEPT JUST FLURRIES IN THE FORECAST FOR
NOW...BUT MAY NEED TO RAMP THINGS UP IF THE FORCING DOES LOOK
LEGIT.
.LONG TERM...THURSDAY THROUGH SUNDAY
306 AM CST MON JAN 21 2013
GOING INTO THE LATER PORTION OF THE WEEK ON INTO THE WEEKEND...THE
MAIN FOCUS IS ON A SYSTEM THAT WILL DROP OUT OF SOUTH CENTRAL
CANADA THURSDAY INTO FRIDAY AND BRING THE NEXT BEST CHANCE FOR AN
ACCUMULATING SNOW WITH IT. TRENDS HAVE WAVERED BACK AND FORTH ON
THE TIMING OF WHEN THIS FEATURE MOVES IN WITH THE 21.00Z GFS/ECMWF
SLOWING IT DOWN A TAD WITH MUCH OF THE SNOW FALLING THURSDAY
AFTERNOON INTO FRIDAY MORNING. 21.00Z GFS BUFKIT SOUNDINGS FOR
THIS EVENT SHOW A FAIRLY DEEP DENDRITIC GROWTH ZONE WITH FORCING
THROUGH THIS LAYER WHICH COULD LEAD TO SOME HIGH SNOW RATIOS.
DETAILS WILL NEED TO BE WORKED OUT ON THIS SYSTEM...BUT IT LOOKS
LIKE THE POTENTIAL IS THERE FOR AN ACCUMULATING SNOW...WITH THE
BETTER CHANCES FOR ACCUMULATIONS IN CENTRAL WISCONSIN.
TEMPERATURE-WISE...WE ARE STILL IN NORTHWEST FLOW ALOFT...SO THE
COOL AIR WILL REMAIN IN PLACE THOUGH NEXT WEEKEND WITH
TEMPERATURES LINGERING MAINLY JUST BELOW NORMAL.
&&
.AVIATION...TODAY AND TONIGHT
521 AM CST MON JAN 21 2013
PLAN ON BRISK NORTHWEST WINDS CONTINUING AT THE KRST/KLSE TAF
SITES TODAY AS PRESSURE GRADIENT REMAINS FAIRLY TIGHT BETWEEN LOW
PRESSURE OVER THE GREAT LAKES AND HIGH PRESSURE BUILDING IN FROM
THE DAKOTAS. VERY COLD CYCLONIC FLOW ALOFT AND WEAK LIFT WILL ALSO
PRODUCE SCATTERED STRATOCUMULUS AND A FEW FLURRIES. EXPECTING VFR
CONDITIONS THROUGH TONIGHT WITH WINDS SUBSIDING DURING THE EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CST MON JAN 21 2013
WI...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS MIAMI FL
1236 PM EST MON JAN 21 2013
.AVIATION...
SHOWERS WERE BEGINNING TO DEVELOP ALONG THE EAST COAST IN BROWARD
AND PALM BEACH COUNTIES EARLY THIS AFTERNOON ALONG THE EAST COAST
SEA BREEZE. HRRR INDICATES SHOWER ACTIVITY INCREASING ALONG THE
EAST COAST THIS AFTERNOON AHEAD OF THE COLD FRONT...ESPECIALLY
ACROSS BROWARD AND PALM BEACH COUNTIES. ADDED VCSH TO THE EAST
COAST TAF SITES AND MVFR CONDITIONS WILL BE POSSIBLE THROUGH THE
AFTERNOON. WINDS MAY SHIFT TO THE SOUTHWEST AROUND 22Z AT THE EAST
COAST TAF SITES...AND THEN NORTHWEST AFTER 02Z. AT KAPF...A LOW
STRATUS DECK WAS FINALLY BEGINNING TO SCATTER OUT. LOW STRATUS MAY
BE POSSIBLE LATE TONIGHT AT KAPF AS WELL. THE FRONT IS EXPECTED
TO CLEAR THE REGION BY 12Z TUESDAY. WINDS WILL INCREASE TO AROUND
12 KNOTS AND SHIFT TO THE NORTHEAST BY THE END OF THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 918 AM EST MON JAN 21 2013/
..FEW SHOWERS THIS AFTERNOON, FOCUSED EAST COAST, THEN A COOLER
AND DRIER AIRMASS MOVES IN BEHIND A WEAK COLD FRONT THIS EVENING...
UPDATE...A FEW SHOWERS HAVE AFFECTED THE IMMEDIATE ATLANTIC COAST
THIS MORNING. A MORE ORGANIZED AREA OF SHOWERS IS OFF THE FAR
SOUTHERN MIAMI-DADE COAST BEYOND 30 NM OF THE COAST (LOOKS LIKE A
MESOLOW) AND MOVING AWAY FROM THE AREA. THE MORNING MIAMI
SOUNDING SHOWED LOW LEVEL MOISTURE WITH A PWAT OF 1.29 INCHES. WE
STILL HAVE A NICE INVERSION AT AROUND 8K FT. MOISTURE IS PROGGED
TO INCREASE ALONG THE ATLANTIC COAST THIS AFTERNOON...WITH FCST
PWATS TO AROUND 1.4 INCHES. LOW CAPE THOUGH. HOWEVER, MESOSCALE
MODELS AND EVEN GFS SHOW QPF MAXIMIZING ALONG THE ATLANTIC COAST
THIS AFTERNOON AS A SEA BREEZE DEVELOPS RESULTING IN CONVERGENCE
ON THE SYNOPTIC SCALE SW WIND FLOW THIS AFTERNOON RIGHT AHEAD OF A
WEAK COLD FRONT. GIVEN THIS HAVE INCREASED POPS A BIT FOR TODAY.
THE FEW SHOWERS WHICH DEVELOP WILL BRING SOME HEAVY DOWNPOURS BUT
WILL QUICKLY MOVE OFF THE COAST EARLY THIS EVENING WITH THE COOLER
AND DRIER AIRMASS MOVING INTO SOUTH FL TONIGHT. /GREGORIA
PREV DISCUSSION... /ISSUED 607 AM EST MON JAN 21 2013/
AVIATION...
MID LEVEL BKN TO OVC CIGS HAVE MITIGATED WIDESPREAD FOG DEVELOPMENT
ACROSS THE AREA THIS MORNING. ISOLATED SHOWERS REMAIN OFFSHORE THE
ATLANTIC COAST THIS MORNING AND CONTINUE TO BE BASICALLY STATIONARY
AND ARE NOT AFFECTING THE EAST COAST TERMINALS. GENERALLY LIGHT TO
CALM WINDS SHOULD TURN MORE TO THE EAST SOUTHEAST AND THEN BACK
AROUND TO THE NORTH THROUGH THE LATE AFTERNOON AND EARLY EVENING
HOURS.
PREV DISCUSSION... /ISSUED 224 AM EST MON JAN 21 2013/
SHORT TERM (TODAY-WEDNESDAY)...
THE LATEST NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH THE
FIRST HALF OF THE WEEK AND INDICATES A STRONG/COLD HIGH PRESSURE
BUILDING SOUTHEAST OUT OF THE NRN/CNTRL PLAIN STATES TOWARD AND INTO
NRN FLORIDA THROUGH THE MID-WEEK PERIOD TRAILING A WEAK COLD FRONT.
THE COLD FRONT SHOULD PASS THROUGH SOUTH FLORIDA SOMETIME LATER
TUESDAY USHERING IN SOME DRIER AIR ALONG WITH LIGHT TO MODERATE
NORTHERLY FLOW. THE BEST CHANCE FOR ANY SHOWERS WILL REMAIN OVER THE
ADJACENT ATLANTIC WATERS WITHIN THE MOIST NORTHEAST LOW-LEVEL FLOW.
OTHERWISE...DRIER AND SLIGHTLY COOLER TEMPERATURES CAN BE EXPECTED
BEGINNING TUESDAY NIGHT THROUGH THE MID-WEEK PERIOD. THE LATEST
GUIDANCE IS INDICATING OVERNIGHT LOWS SEVERAL DEGREES COOLER THAN
NORMAL...MAINLY FOR THE INLAND AND NORTHWESTERN LOCATIONS WHERE LOWS
ARE FORECAST TO DIP INTO THE MID 40S TO LOW 50S BY WEDNESDAY
MORNING. FARTHER EAST AND SOUTHEAST TOWARD THE SE FL
COAST...TEMPERATURES ARE FORECAST TO REMAIN AROUND NORMAL WITH
OVERNIGHT LOWS DROPPING INTO THE UPPER 50S JUST INLAND OFF THE COAST
TO THE LOWER 60S NEAR THE COAST.
LONG TERM (THURSDAY-WEEKEND)...
THE LONG-RANGE MODELS REMAIN IN DECENT AGREEMENT THROUGH FRIDAY THEN
BEGIN TO DIFFER REGARDING THE TIMING AND PROGRESSION OF A COLD FRONT
PUSHING INTO THE AREA OVER THE WEEKEND. THE ECMWF PROVIDES THE MORE
BULLISH/FASTER SOLUTION AND INDICATES THE EAST COAST UPPER TROUGH
FURTHER DEEPENING AND DRIVING A COLD FRONT THROUGH FLORIDA FROM
NORTH/SOUTH FRIDAY THROUGH SATURDAY. THE GFS SHOWS A MUCH WEAKER AND
SLOWER SOLUTION WITH THE BOUNDARY MAKING ITS WAY SOUTH ACROSS THE
STATE LATE FRIDAY NIGHT THROUGH SATURDAY NIGHT. THE GFS ENSEMBLE
MEAN (12Z PACKAGE FROM YESTERDAY)...HOWEVER...IS MORE IN LINE WITH
THE FASTER ECMWF. THEREFORE...UNCERTAINTY WITH REGARD TO THE TIMING
OF THIS FEATURE REMAINS HIGH AND WE WILL CONTINUE TO MONITOR LATER
RUNS FOR MORE CONSISTENCY. GUIDANCE IS CURRENTLY NOT INDICATING
TEMPERATURES FLUCTUATING MUCH FROM NORMAL THROUGH WEEKEND AT THIS
TIME.
MARINE...
A STRONG HIGH PRESSURE WILL BUILD SOUTHEAST OVER THE REGION IN THE
WAKE OF THE WEAK COLD FRONT TUESDAY THROUGH THE MID-WEEK PERIOD.
SEAS WILL RESPOND AND BUILD TO MODERATE LEVELS ACROSS THE ATLANTIC
AND OFFSHORE GULF WATERS LATER TUESDAY THROUGH THE MID-WEEK OUT OF
THE NORTH-NORTHEAST. THE BEST CHANCE FOR SHOWERS WILL REMAIN OVER
THE ATLANTIC MARINE AREAS OFF THE SOUTHEAST FLORIDA COAST THROUGH
THE PERIOD.
FIRE WEATHER...
DESPITE THE DRIER COMING IN THE WAKE OF THE COLD FRONT THROUGH THE
MID-WEEK...RELATIVE HUMIDITIES ARE EXPECTED TO REMAIN ABOVE
CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 66 76 62 75 / 10 - - -
FORT LAUDERDALE 66 77 64 76 / 10 - - -
MIAMI 66 78 64 77 / 10 - - -
NAPLES 60 76 56 76 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
312 PM CST MON JAN 21 2013
.DISCUSSION...
1158 AM CST
THE GOING WIND CHILL ADVISORY LOOKS GOOD AND HAVE EXPANDED IT SOME
TO INCLUDE AREAS SOUTH AND EAST OF THE EXISTING ONE. DID THIS
MAINLY FOR IT BEING THE FIRST SIGNIFICANT COLD AIR MASS IN A COUPLE
YEARS AND FOR COLLABORATIVE PURPOSES.
NORTHWEST WINDS CONTINUE TO REGULARLY GUST AT 25 TO 33 MPH ACROSS
THE AREA WITH TEMPERATURES JUST NOW STARTING TO SHOW THE SLIGHTEST
OF RECOVERIES...WITH A DEGREE OR TWO CLIMB IN A FEW LOCATIONS. AN
IMPRESSIVELY DEEP COLD AND DRY AIR MASS WAS IDENTIFIED THIS
MORNING ON AREA RAOBS WITH THE HEART OF THE 850-925MB COLD AIR
MOVING SOUTHEAST FROM THE NORTHEAST MN...LAKE SUPERIOR...AND
WESTERN ONTARIO REGION. WITH THE SURFACE HIGH REMAINING TO THE
WEST TONIGHT...WINDS WILL CONTINUE AT 10 TO 20 MPH...ESPECIALLY IN
THE EVENING. AIR TEMPERATURES WILL BE IN THE SINGLE DIGITS AT
SUNDOWN ALLOWING READINGS TO WORK THEIR WAY TO BELOW ZERO IN
OUTLYING AREAS OF NORTHERN IL BY LATE THIS EVENING/AROUND
MIDNIGHT. MIN TEMPS STILL LOOK ON TRACK...AND IF ANYTHING COULD
EVEN SEE A DEGREE OR TWO COLDER IN SOME PLACES LOOKING BACK AT
PAST BELOW ZERO MINS IN CHICAGO /ORD/ WITH NO SNOW UPSTREAM
/AVERAGE OF -4F/. MORE ON THAT IN THE AFTERNOON AFD. WITH THESE
FORECAST TEMPS AND NO CHANGES TO WINDS...THE FORECAST WIND CHILLS
BOTTOM OUT -20 TO -25 IN THE NORTHERN PART OF THE ADVISORY AND
NEAR -20 IN THE SOUTHERN PORTION. WITH THE -15 CRITERIA THAT OUR
EASTERN CWA NWS NEIGHBORS HAVE...THEY WILL SEE THAT REACHED MORE
EASILY THAN OUR EASTERN COUNTIES. HAVE OPTED THOUGH TO JUST FILL
THAT AREA IN FOR THE PUBLIC MESSAGE PURPOSE...AS THIS AIR MASS
WILL BE THE FIRST SIGNIFICANT COLD OF THE SEASON AND IN A COUPLE
SEASONS TO THIS MAGNITUDE.
MTF
//PREV DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SCT CIGS THRU THIS EVE...MAY THIN FURTHER TO A FEW DECK ARND
3KFT AGL.
* W/NW WINDS WILL PERSIST WITH SUSTAINED WINDS ARND
14KT...OCCASIONAL GUSTS TO 20 KT OR ARND 20 KT.
* BREEZY WINDS WILL DIMINISH OVERNIGHT...RETURN AGAIN TUE MIDDAY
WITH GUSTS TO 20 KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ARCTIC AIR MASS CONTINUES TO SLOWLY FILTER INTO THE GREAT LAKES
REGION...WITH VERY COLD AND DRY CONDITIONS. THE DRY AIR WILL
CONTINUE TO PROVIDE A THINNING CLOUD COVER OVER ORD/MDW AND ALL
OTHER TAF SITES ACROSS NORTHERN IL THIS EVENING. SO THE REMAINING
BKN CIGS ACROSS ORD/MDW ARE EXPECTED TO DISSIPATE TO A SCT
DECK...THEN EVENTUALLY TO A FEW CLOUDS ARND 3KFT AGL. IT IS
POSSIBLE THAT A FEW SNOW FLAKES WILL FLOAT ACROSS THE
SKY...HOWEVER IT IS NOT EXPECTED TO POSE AN IMPACT TO AVIATION.
THE GRADIENT DOES REMAIN ELEVATED...SO HAVE MAINTAINED WINDS
SUSTAINED ARND 14KT WITH GUSTS ARND 20KT. AT TIMES GUSTS MAY BE
LOWER...HOWEVER THE MAJORITY OF THE GUSTS WILL BE IN THE UPPER
TEENS TO ARND 20 KT. THEN WINDS FOR TUE WILL CONTINUE TO BE BREEZY
AT TIMES FROM THE NORTHWEST. CLOUDS WILL REMAIN MINIMAL WITH VFR
CONDS DOMINATING THE SKY...ANY CLOUDS WILL BE ARND 3KFT AGL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
309 PM CST
NW TO W WINDS GUSTING BTWN 30 AND 35 KT WILL SLOWLY DIMINISH
OVERNIGHT INTO TUESDAY MORNING AS HIGH PRESSURE SPREADS ACROSS THE
LAKE. IN FACT ONLY EXPECTING OCCASIONAL LOW END GALES THROUGH THIS
EVENING. PERSISTENT WEST FLOW AROUND 20 KT WILL STICK AROUND
THROUGH WEDNESDAY EVENING. THE WINDS THEN TURN NORTHEAST AS HIGH
PRESSURE MOVES IN FROM THE NORTHEAST. 10 TO 15 KT WINDS CONTINUE
TO TURN TO THE SOUTHEAST THURSDAY BEFORE BECOMING NORTH AS LOW
PRESSURE PASSES SOUTH OF THE LAKE FRIDAY. NORTHERLY FLOW CONTINUES
THROUGH SATURDAY AS THE NEXT HIGH PRESSURE SYSTEM APPROACHES WITH
WINDS SOUTHWEST BEHIND THE HIGH SATURDAY NIGHT.
FOR THE NEARSHORE WATERS...WIND SPEEDS WILL DIMINISH TONIGHT TO
BELOW SMALL CRAFT CRITERIA...BUT LARGE WAVES WILL REMAIN A HAZARD.
STILL THINKING HAZARDOUS WAVES WILL FINALLY DIMINISH LATE TUESDAY
AFTERNOON ALONG THE ILLINOIS NEARSHORE WATERS...BUT EXTENDED THE
SMALL CRAFT FOR THE INDIANA NEARSHORE WATERS THROUGH WEDNESDAY
MORNING. WAVES LOOK LIKE THEY WILL TAKE A LITTLE LONGER TO COME
DOWN AFTER THE PERSISTENT FLOW.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023 UNTIL 10 AM TUESDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
10 AM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
155 PM CST MON JAN 21 2013
.DISCUSSION...
1158 AM CST
THE GOING WIND CHILL ADVISORY LOOKS GOOD AND HAVE EXPANDED IT SOME
TO INCLUDE AREAS SOUTH AND EAST OF THE EXISTING ONE. DID THIS
MAINLY FOR IT BEING THE FIRST SIGNIFICANT COLD AIR MASS IN A COUPLE
YEARS AND FOR COLLABORATIVE PURPOSES.
NORTHWEST WINDS CONTINUE TO REGULARLY GUST AT 25 TO 33 MPH ACROSS
THE AREA WITH TEMPERATURES JUST NOW STARTING TO SHOW THE SLIGHTEST
OF RECOVERIES...WITH A DEGREE OR TWO CLIMB IN A FEW LOCATIONS. AN
IMPRESSIVELY DEEP COLD AND DRY AIR MASS WAS IDENTIFIED THIS
MORNING ON AREA RAOBS WITH THE HEART OF THE 850-925MB COLD AIR
MOVING SOUTHEAST FROM THE NORTHEAST MN...LAKE SUPERIOR...AND
WESTERN ONTARIO REGION. WITH THE SURFACE HIGH REMAINING TO THE
WEST TONIGHT...WINDS WILL CONTINUE AT 10 TO 20 MPH...ESPECIALLY IN
THE EVENING. AIR TEMPERATURES WILL BE IN THE SINGLE DIGITS AT
SUNDOWN ALLOWING READINGS TO WORK THEIR WAY TO BELOW ZERO IN
OUTLYING AREAS OF NORTHERN IL BY LATE THIS EVENING/AROUND
MIDNIGHT. MIN TEMPS STILL LOOK ON TRACK...AND IF ANYTHING COULD
EVEN SEE A DEGREE OR TWO COLDER IN SOME PLACES LOOKING BACK AT
PAST BELOW ZERO MINS IN CHICAGO /ORD/ WITH NO SNOW UPSTREAM
/AVERAGE OF -4F/. MORE ON THAT IN THE AFTERNOON AFD. WITH THESE
FORECAST TEMPS AND NO CHANGES TO WINDS...THE FORECAST WIND CHILLS
BOTTOM OUT -20 TO -25 IN THE NORTHERN PART OF THE ADVISORY AND
NEAR -20 IN THE SOUTHERN PORTION. WITH THE -15 CRITERIA THAT OUR
EASTERN CWA NWS NEIGHBORS HAVE...THEY WILL SEE THAT REACHED MORE
EASILY THAN OUR EASTERN COUNTIES. HAVE OPTED THOUGH TO JUST FILL
THAT AREA IN FOR THE PUBLIC MESSAGE PURPOSE...AS THIS AIR MASS
WILL BE THE FIRST SIGNIFICANT COLD OF THE SEASON AND IN A COUPLE
SEASONS TO THIS MAGNITUDE.
MTF
//PREV DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SCT CIGS THRU THIS EVE...MAY THIN FURTHER TO A FEW DECK ARND
3KFT AGL.
* W/NW WINDS WILL PERSIST WITH SUSTAINED WINDS ARND
14KT...OCCASIONAL GUSTS TO 20 KT OR ARND 20 KT.
* BREEZY WINDS WILL DIMINISH OVERNIGHT...RETURN AGAIN TUE MIDDAY
WITH GUSTS TO 20 KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ARCTIC AIR MASS CONTINUES TO SLOWLY FILTER INTO THE GREAT LAKES
REGION...WITH VERY COLD AND DRY CONDITIONS. THE DRY AIR WILL
CONTINUE TO PROVIDE A THINNING CLOUD COVER OVER ORD/MDW AND ALL
OTHER TAF SITES ACROSS NORTHERN IL THIS EVENING. SO THE REMAINING
BKN CIGS ACROSS ORD/MDW ARE EXPECTED TO DISSIPATE TO A SCT
DECK...THEN EVENTUALLY TO A FEW CLOUDS ARND 3KFT AGL. IT IS
POSSIBLE THAT A FEW SNOW FLAKES WILL FLOAT ACROSS THE
SKY...HOWEVER IT IS NOT EXPECTED TO POSE AN IMPACT TO AVIATION.
THE GRADIENT DOES REMAIN ELEVATED...SO HAVE MAINTAINED WINDS
SUSTAINED ARND 14KT WITH GUSTS ARND 20KT. AT TIMES GUSTS MAY BE
LOWER...HOWEVER THE MAJORITY OF THE GUSTS WILL BE IN THE UPPER
TEENS TO ARND 20 KT. THEN WINDS FOR TUE WILL CONTINUE TO BE BREEZY
AT TIMES FROM THE NORTHWEST. CLOUDS WILL REMAIN MINIMAL WITH VFR
CONDS DOMINATING THE SKY...ANY CLOUDS WILL BE ARND 3KFT AGL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023...6 PM MONDAY TO 10 AM TUESDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
MONDAY TO 10 AM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1207 PM CST MON JAN 21 2013
.DISCUSSION...
1158 AM CST
THE GOING WIND CHILL ADVISORY LOOKS GOOD AND HAVE EXPANDED IT SOME
TO INCLUDE AREAS SOUTH AND EAST OF THE EXISTING ONE. DID THIS
MAINLY FOR IT BEING THE FIRST SIGNIFICANT COLD AIR MASS IN A COUPLE
YEARS AND FOR COLLABORATIVE PURPOSES.
NORTHWEST WINDS CONTINUE TO REGULARLY GUST AT 25 TO 33 MPH ACROSS
THE AREA WITH TEMPERATURES JUST NOW STARTING TO SHOW THE SLIGHTEST
OF RECOVERIES...WITH A DEGREE OR TWO CLIMB IN A FEW LOCATIONS. AN
IMPRESSIVELY DEEP COLD AND DRY AIR MASS WAS IDENTIFIED THIS
MORNING ON AREA RAOBS WITH THE HEART OF THE 850-925MB COLD AIR
MOVING SOUTHEAST FROM THE NORTHEAST MN...LAKE SUPERIOR...AND
WESTERN ONTARIO REGION. WITH THE SURFACE HIGH REMAINING TO THE
WEST TONIGHT...WINDS WILL CONTINUE AT 10 TO 20 MPH...ESPECIALLY IN
THE EVENING. AIR TEMPERATURES WILL BE IN THE SINGLE DIGITS AT
SUNDOWN ALLOWING READINGS TO WORK THEIR WAY TO BELOW ZERO IN
OUTLYING AREAS OF NORTHERN IL BY LATE THIS EVENING/AROUND
MIDNIGHT. MIN TEMPS STILL LOOK ON TRACK...AND IF ANYTHING COULD
EVEN SEE A DEGREE OR TWO COLDER IN SOME PLACES LOOKING BACK AT
PAST BELOW ZERO MINS IN CHICAGO /ORD/ WITH NO SNOW UPSTREAM
/AVERAGE OF -4F/. MORE ON THAT IN THE AFTERNOON AFD. WITH THESE
FORECAST TEMPS AND NO CHANGES TO WINDS...THE FORECAST WIND CHILLS
BOTTOM OUT -20 TO -25 IN THE NORTHERN PART OF THE ADVISORY AND
NEAR -20 IN THE SOUTHERN PORTION. WITH THE -15 CRITERIA THAT OUR
EASTERN CWA NWS NEIGHBORS HAVE...THEY WILL SEE THAT REACHED MORE
EASILY THAN OUR EASTERN COUNTIES. HAVE OPTED THOUGH TO JUST FILL
THAT AREA IN FOR THE PUBLIC MESSAGE PURPOSE...AS THIS AIR MASS
WILL BE THE FIRST SIGNIFICANT COLD OF THE SEASON AND IN A COUPLE
SEASONS TO THIS MAGNITUDE.
MTF
&&
.PREV DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* OCCASIONAL BKN 3000FT CIGS...MAINLY SCT CIGS THRU THIS AFTN.
* W/NW WINDS WILL PERSIST WITH SUSTAINED WINDS ARND
14KT...OCCASIONAL GUSTS TO 20 KT OR ARND 20 KT.
* BREEZY WINDS WILL DIMINISH OVERNIGHT...RETURN AGAIN TUE MIDDAY
WITH GUSTS TO 20 KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ARCTIC AIR MASS CONTINUES TO SLOWLY FILTER INTO THE GREAT LAKES
REGION...WITH VERY COLD AND DRY CONDITIONS. THE DRY AIR WILL
CONTINUE TO PROVIDE A THINNING CLOUD COVER OVER ORD/MDW AND ALL
OTHER TAF SITES ACROSS NORTHERN IL THIS EVENING. SO THE REMAINING
BKN CIGS ACROSS ORD/MDW ARE EXPECTED TO DISSIPATE TO A SCT
DECK...THEN EVENTUALLY TO A FEW CLOUDS ARND 3KFT AGL. IT IS
POSSIBLE THAT A FEW SNOW FLAKES WILL FLOAT ACROSS THE
SKY...HOWEVER IT IS NOT EXPECTED TO POSE AN IMPACT TO AVIATION.
THE GRADIENT DOES REMAIN ELEVATED...SO HAVE MAINTAINED WINDS
SUSTAINED ARND 14KT WITH GUSTS ARND 20KT. AT TIMES GUSTS MAY BE
LOWER...HOWEVER THE MAJORITY OF THE GUSTS WILL BE IN THE UPPER
TEENS TO ARND 20 KT. THEN WINDS FOR TUE WILL CONTINUE TO BE BREEZY
AT TIMES FROM THE NORTHWEST. CLOUDS WILL REMAIN MINIMAL WITH VFR
CONDS DOMINATING THE SKY...ANY CLOUDS WILL BE ARND 3KFT AGL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023...6 PM MONDAY TO 10 AM TUESDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
MONDAY TO 10 AM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1159 AM CST MON JAN 21 2013
.DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* OCCASIONAL BKN 3000FT CIGS...MAINLY SCT CIGS THRU THIS AFTN.
* W/NW WINDS WILL PERSIST WITH SUSTAINED WINDS ARND
14KT...OCCASIONAL GUSTS TO 20 KT OR ARND 20 KT.
* BREEZY WINDS WILL DIMINISH OVERNIGHT...RETURN AGAIN TUE MIDDAY
WITH GUSTS TO 20 KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ARCTIC AIR MASS CONTINUES TO SLOWLY FILTER INTO THE GREAT LAKES
REGION...WITH VERY COLD AND DRY CONDITIONS. THE DRY AIR WILL
CONTINUE TO PROVIDE A THINNING CLOUD COVER OVER ORD/MDW AND ALL
OTHER TAF SITES ACROSS NORTHERN IL THIS EVENING. SO THE REMAINING
BKN CIGS ACROSS ORD/MDW ARE EXPECTED TO DISSIPATE TO A SCT
DECK...THEN EVENTUALLY TO A FEW CLOUDS ARND 3KFT AGL. IT IS
POSSIBLE THAT A FEW SNOW FLAKES WILL FLOAT ACROSS THE
SKY...HOWEVER IT IS NOT EXPECTED TO POSE AN IMPACT TO AVIATION.
THE GRADIENT DOES REMAIN ELEVATED...SO HAVE MAINTAINED WINDS
SUSTAINED ARND 14KT WITH GUSTS ARND 20KT. AT TIMES GUSTS MAY BE
LOWER...HOWEVER THE MAJORITY OF THE GUSTS WILL BE IN THE UPPER
TEENS TO ARND 20 KT. THEN WINDS FOR TUE WILL CONTINUE TO BE BREEZY
AT TIMES FROM THE NORTHWEST. CLOUDS WILL REMAIN MINIMAL WITH VFR
CONDS DOMINATING THE SKY...ANY CLOUDS WILL BE ARND 3KFT AGL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023...6 PM MONDAY TO 10 AM TUESDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
MONDAY TO 10 AM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1015 AM CST MON JAN 21 2013
.DISCUSSION...
339 AM CST
MAIN CONCERNS/CHALLENGES ARE WITH MUCH COLDER AIR KNOCKING ON OUR
DOORSTEPS THIS MORNING...SOME PERIODIC CHANCES FOR FLURRIES
THROUGH MID WEEK...AS WELL AS A POSSIBILITY FOR OUR FIRST
ACCUMULATING SNOWFALL ARRIVING THURSDAY. WITH THE COLD TEMPS/LOW
WIND CHILLS...HAVE ISSUED A WIND CHILL ADVISORY FOR THE NORTHERN
TWO TIERS OF COUNTIES IN ILLINOIS FOR TONIGHT INTO TUESDAY
MORNING.
CHILLY AIR IN PLACE THIS MORNING AS TEMPS ARE IN THE LOWER TEENS
AND SINGLE DIGITS AT THIS HOUR...WHILE SCATTERED FLURRIES ARE
ONGOING ACROSS THE CWA AT THIS TIME. LATEST SATELLITE IMAGERY
DEPICTING LONGWAVE TROUGH CURRENTLY DIGGING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST...WITH SEVERAL SHORT WAVE TROUGHS
STREAMING OUT AHEAD OF IT. OF WORTHY TO MENTION WITH THIS LONGWAVE
TROUGH ARE THE HIGH SPEEDS CURRENTLY BEING OBSERVED ALOFT...WITH
LATEST RAP ANALYSIS SHOWING 90-100KT AT 500MB. THESE SHORT WAVE
TROUGHS EMBEDDED IN THIS RATHER STRONG FLOW ALOFT ARE HELPING FOR
CLOUD COVER TO BLOSSOM OVERHEAD THIS MORNING WITH BOTH MID AND LOW
LEVEL CLOUD COVER IN PLACE. EXPECT THIS CLOUD COVER TO SLIGHTLY
INCREASE IN OVERALL COVERAGE THIS MORNING WILL ALL AREAS ACROSS
NORTHEAST ILLINOIS AND NORTHWEST INDIANA TO START OFF MOSTLY
CLOUDY. THIS LIFT COINCIDING WITHIN THIS COLD AIR MASS AND STEEP
LOW LEVEL LAPSE RATES...PER LATEST RAP ANALYSIS AND AMDAR
SOUNDINGS...HAS ALLOWED FOR SOME SOME SCATTERED FLURRY ACTIVITY
ACROSS THE CWA THIS MORNING. LATEST RADAR ANALYSIS DEPICTING THIS
ACTIVITY AT THIS TIME WITH SEVERAL SITES REPORTING LIGHT SNOW.
EXPECT THESE FLURRIES TO REMAIN POSSIBLE ACROSS THE ENTIRE AREA
THROUGH PRIMARILY MID MORNING...AND HAVE MADE MENTION OF THIS
POSSIBILITY IN THE GRIDS. CLOUD COVER WILL ALSO LINGER ACROSS THE
CWA AT LEAST THROUGH MID MORNING BUT WITH LATEST SHORT TERM
GUIDANCE HINTING AT THE POSSIBILITY THAT THESE CLOUDS COULD LINGER
AROUND THROUGH MID DAY. SO HAVE SLOWED THE CLEARING TREND THROUGH
LATE MORNING BASED ON LATEST TRENDS AS WELL AS THIS GUIDANCE...BUT
WITH CLEARING DEFINITELY ANTICIPATED BY EARLY THIS AFTERNOON.
THE ANTICIPATED MUCH COLDER AIR CONTINUES TO BARREL SOUTH ACROSS
THE UPPER MIDWEST WITH LATEST RAP ANALYSIS DEPICTING 850MB TEMPS
OF -21C PUSHING INTO NORTHERN ILLINOIS THIS MORNING. EXPECT THIS
AIRMASS TO CONTINUE DROPPING SOUTH THROUGH THIS MORNING...WITH THE
CURRENT SINGLE DIGIT/LOWER TEENS TEMPS WHICH WILL BE OBSERVED OVER
THE NEXT COUPLE OF HOURS TO PRETTY MUCH BE OUR HIGH TEMPS TODAY. A
SECONDARY PUSH OF COLD AIR OVER THE NEXT SEVERAL HOURS WILL RESULT
IN FALLING TEMPS THROUGHOUT TODAY. WITH THESE COLD TEMPS AND A
STIFF NORTHWEST WIND STILL IN PLACE TODAY...LOW WIND CHILL
READINGS OF -10 UP TO -20 WILL MAKE FOR A COLD DAY. STILL EXPECT
TONIGHT TO BE THE COLDEST OF THE NIGHTS AS THIS COLD AIRMASS
SETTLES IN ACROSS THE REGION WITH FORECAST TEMPS OF 0 TO -5
DEGREES ACROSS NORTHERN ILLINOIS AND TEMPS AROUND 1-2 DEGREES
ELSEWHERE. DANGEROUSLY LOW WIND CHILL READINGS OF -15 TO -25 WILL
RESULT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA TONIGHT. SO
HAVE OPTED TO ISSUE A WIND CHILL ADVISORY AT THIS TIME FOR THE
NORTHERN TWO TIERS OF COUNTIES ACROSS NORTHERN ILLINOIS WITH THESE
AREAS LIKELY OBSERVING -20 TO -25 WIND CHILL READINGS STARTING
EARLY THIS EVENING AND PERSISTING THROUGH MID MORNING TUESDAY. DO
EXPECT THE LOWEST TEMPS AND WIND CHILL READINGS TO BE OBSERVED
MORE TOWARDS THE ILLINOIS/WISCONSIN BORDER.
COLD AIRMASS TO STILL BE IN PLACE ON TUESDAY WITH HIGH TEMPS OF
SINGLE DIGITS TO LOWER TEENS LIKELY ONCE AGAIN. THE ONLY RELIEF
WILL BE A LOWER WIND FIELD ACROSS THE AREA AS WELL AS FULL
SUNSHINE IN PLACE. DESPITE THIS COLD...RELATIVELY QUIET WEATHER
EXPECTED FOR OUR CWA THROUGH MID WEEK. MODELS CONTINUE TO STRUGGLE
WITH HANDLING THESE WAVES TRAVERSING THIS NORTHWEST FLOW THROUGH
MID WEEK... WITH SOME GUIDANCE DEVELOPING SOME LIGHT QPF TUESDAY
NIGHT INTO WEDNESDAY. DESPITE THE MODELS HINTING AT THIS...HAVE
OPTED TO LEAVE OUT ANY MENTION OF FLURRIES AT THIS TIME. ALTHOUGH
THE POSSIBILITY FOR FLURRIES IS THERE...THE TREND OVER THE LAST
COUPLE OF DAYS HAS BEEN DRY AND FOR THE MODELS TO FLIP FLOP ON
LOCATION AND TIMING. ALSO...IF IT WERE TO OCCUR...ANYTHING THAT
WOULD DEVELOP WOULD BE AT MOST FLURRY ACTIVITY WITH PRETTY MUCH
NIL ACCUMULATION. LAST...MODELS CONTINUE TO STRUGGLE THIS MORNING
WITH THE NEXT STRONGER SYSTEM DUE TO ARRIVE SOMETIME ON THURSDAY.
PLACEMENT AND TIMING CONTINUE TO BE AN ISSUE FOR ALL MODELS AND SO
AM NOT OVERLY EXCITED AT THIS TIME FOR THIS SYSTEM AND AN
ACCUMULATING SNOWFALL. WILL CONTINUE TO MONITOR IT THOUGH...AS
PREVIOUS RUNS HAVE INDICATED FOR SOME ACCUMULATING SNOWFALL FOR A
GOOD PORTION OF THE CWA...AS WELL AS EVEN OF THE LATEST MODEL RUNS
THIS MORNING.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CIGS BECOMING VFR WITH A FEW POCKETS OF MVFR CIGS REMAINING.
* WIDELY SCATTERED FLURRIES.
* GUSTY WEST-NORTHWEST WINDS AROUND 25 KTS THROUGH THE DAY.
BEACHLER
//DISCUSSION...UPDATED 12Z...
A REINFORCING PUSH OF COLD ARCTIC AIR WAS MOVING ACROSS NORTHERN
ILLINOIS EARLY THIS MORNING...ACCOMPANIED BY AN UPPER LEVEL
DISTURBANCE WHICH WAS HELPING TO PRODUCE PATCHY LIGHT SNOW SHOWERS
AND FLURRIES. THE COLD FRONT AND UPPER LEVEL WAVE SHOULD PUSH
ACROSS THE TERMINALS BY MID MORNING...WITH EVENTUAL SCATTERING OF
LOWER CLOUDS...AND BLUSTERY WINDS IN THE 290-300 DEGREE RANGE
GUSTING AROUND 25 KTS FOR THE REMAINDER OF THE DAY. DUE TO THE DRY
NATURE OF THE COLD ARCTIC AIR...COVERAGE OF MVFR CIGS AND SNOW
SHOWERS HAS BEEN SOMEWHAT PATCHY OVERNIGHT/EARLY THIS MORNING...
AND WILL LIKELY CONTINUE TO BE THE SAME UNTIL CLOUDS DECREASE
LATER THIS MORNING WITH INCREASING SUBSIDENCE BEHIND THE DEPARTING
UPPER TROUGH.
WINDS WILL REMAIN GUSTY EVEN INTO THE EVENING HOURS TONIGHT...
THOUGH GUST SPEEDS SHOULD GRADUALLY DECREASE AFTER SUNSET.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN CIGS IMPROVING TO VFR BY MIDDAY.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY AND SUNDAY...VFR.
RATZER
&&
.MARINE...
247 AM CST
GUSTY WEST-NORTHWEST WINDS REMAIN THE MAIN FOCUS OF THE MARINE
FORECAST INTO WEDNESDAY.
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GREAT
LAKES REGION...BETWEEN A RELATIVELY WEAK AREA OF LOW PRESSURE ACROSS
THE NORTHERN LAKES AND COLD HIGH PRESSURE SPREADING SOUTHEAST ACROSS
THE PLAINS. WINDS WILL PICK UP A BIT TODAY AS A REINFORCING PUSH OF
COLDER AIR MOVES INTO THE REGION...WITH SPEEDS AROUND 30 KTS ACROSS
THE LAKE THIS MORNING INTO TUESDAY MORNING. COULD BE SOME GALE FORCE
GUSTS TO 35 KT...THOUGH MODEL SOUNDINGS DONT INDICATE SUPPORT FOR
WIDESPREAD OR LONG-LASTING GALES AT THIS TIME. 25-30 KT SUSTAINED
WINDS AND COLDER TEMPS IN THE SINGLE DIGITS TO LOWER TEENS SHOULD
RESULT IN MODERATE FREEZING SPRAY REDEVELOPING THIS MORNING AND
PERSISTING INTO EARLY TUESDAY. SHOULD GUSTS ABOVE 30 KT BECOME
PREVALENT A HEAVY FREEZING SPRAY WARNING COULD BE NEEDED AND WILL BE
MONITORED FOR...BUT THIS DOES NOT APPEAR NECESSARY AT THIS TIME.
WINDS WILL THEN VERY GRADUALLY DIMINISH LATE TUESDAY INTO WEDNESDAY
AS THE PLAINS HIGH WEAKENS AND MOVES SOUTHEAST THROUGH THE OHIO
VALLEY AND INTO THE SOUTHEASTERN STATES. ANOTHER HIGH SPREADS
SOUTHEAST ACROSS ONTARIO AND THE UPPER MIDWEST LATE WEDNESDAY AND
THURSDAY...WHILE ANOTHER LOW DEVELOPS OVER THE SOUTHERN PLAINS.
LONGER RANGE MODEL SOLUTIONS CONTINUE TO BRING THIS LOW THROUGH THE
LOWER OHIO VALLEY BY THURSDAY NIGHT...WITH THE HIGH WEAKENING ACROSS
ONTARIO AND THE GREAT LAKES REGION. THUS WINDS WILL DIMINISH IN THE
VICINITY OF THE WEAKENING RIDGE FOR A TIME LATER WEDNESDAY NIGHT AND
THURSDAY...BEFORE BECOMING MORE EASTERLY AS THE LOW APPROACHES AND
PASSES SOUTH OF THE LAKE...AND THEN NORTH-NORTHWEST AS IT PASSES ON
FRIDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014...6 PM MONDAY TO 9 AM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
320 PM CST MON JAN 21 2013
.DISCUSSION...
TODAY-WED:
COMPLEX SURFACE PATTERN WITH REALLY COLD AIR SLOWLY BACKDOORING
INTO FORECAST AREA...AND SOME RETURN FLOW DEVELOPING IN FAR
WESTERN SECTIONS. NOT A LOT OF CONFIDENCE IN ANY OF THE MODELS
ABILITY TO RESOLVE LOCATION OF COLDEST AIR AND RESULTANT LOW
CLOUDS. BEST GUESS IS FOR COLD AIR TO CONTINUE TO SAG AT LEAST
OVERNIGHT... POTENTIALLY LEAVING A SHARP BOUNDARY SOMEWHERE ACROSS
THE AREA ON TUE. ANTICIPATE ANY LOW CLOUDS EARLY IN THE MORNING
WILL BE ERODED FAIRLY QUICKLY AND WILL HAVE FAIR AMOUNT OF
MODIFICATION OF COLD AIR NEAR BOUNDARY. BEST GUESS FOR WED IS
LITTLE SURFACE FLOW... PROBABLY OUT OF THE EAST. THIS SHOULD
RECIRCULATE COOL AIR...SO NOT EXPECTING MUCH RECOVERY AT THIS TIME.
WED NIGHT-FRI:
RETURN FLOW BEGINS TO DEVELOP ON BOTH ECMWF/GFS...WITH BOTH
SHOWING 850MB MOISTURE WORKING NORTH...PRIMARY AFFECTING SOUTHERN
SECTIONS DURING THE PERIOD. REMAINS TO BE SEEN WHETHER THERE WILL
BE ENOUGH LIFT/MOISTURE TO OVERCOME DRY AIR NEAR SURFACE. BEST
LIFT COMES THU AFTERNOON AND ESPECIALLY FRI MORNING. BEST CHANCE
FOR PRECIPITATION THU WILL LIKELY BE IN SOUTHEAST KS IN THE
AFTERNOON. BY FRI MORNING DRIER AIR WILL HAVE OVERSPREAD THE
ENTIRE AREA. COLDER AIR SHOULD BE SPILLING INTO THE AREA ON
FRI...WITH HIGH TEMPERATURES LOWER THAN ON THU.
SAT-MON:
GOOD AGREEMENT THAT LARGE SURFACE HIGH WILL DROP SOUTH ACROSS THE
PLAINS ON SAT...WITH RETURN FLOW DEVELOPING ON SUN. HOWEVER SPREAD
BETWEEN GFS/ECMWF STARTS TO INCREASE SIGNIFICANTLY DUE TO HANDLING
OF SHORTWAVE MOVING THROUGH AND LONG WAVE TROUGH IN THE WESTERN
US. BOTH APPEAR TO BE OVERLY AGRESSIVE WITH RETURN MOISTURE ON SUN
AND MON AND HAVE OPTED TO KEEP FORECAST DRY FOR NOW. GIVEN SOUTHERN
EXTENT OF SURFACE HIGH AND SURFACE TRAJECTORIES DURING THE PERIOD...
SEEMS UNLIKELY TO GET SUFFICIENT MOISTURE THIS FAR NORTH THAT QUICK.
SHOULD SEE TEMPERATURES REBOUND NICELY GIVEN RELATIVELY DRY AIR/DRY
GROUND/SUNSHINE AND RETURN FLOW. -HOWERTON
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
KRSL-KSLN-KCNU WILL BE FLIRTING WITH LOW VFR TO HIGH MVFR CIGS
THIS AFTERNOON-EVENING...AND POSSIBLY THROUGH TONIGHT...AS
SHALLOW COLD AIR TIED TO ARCTIC HIGH PRESSURE ENCROACHES FROM THE
NORTHEAST. FOR NOW PLAYED THE CONSERVATIVE APPROACH...ALTHOUGH IF
LATEST RUC BUFR SOUNDINGS VERIFY CIGS LESS THAN 2000 FT AGL COULD
PREVAIL AS FAR SOUTH AS KHUT AND KICT BY MIDNIGHT. MODELS TEND TO
NOT HANDLE SHALLOW COLD AIRMASSES VERY WELL...SO WILL CONTINUE TO
MONITOR.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 20 45 26 52 / 0 0 0 0
HUTCHINSON 19 44 25 51 / 0 0 0 0
NEWTON 19 42 25 50 / 0 0 0 0
ELDORADO 18 41 25 52 / 0 0 0 0
WINFIELD-KWLD 21 46 27 57 / 0 0 0 0
RUSSELL 17 40 22 51 / 0 0 0 0
GREAT BEND 20 44 25 52 / 0 0 0 0
SALINA 17 38 22 49 / 0 0 0 0
MCPHERSON 18 42 24 50 / 0 0 0 0
COFFEYVILLE 19 44 27 58 / 0 0 10 10
CHANUTE 17 39 24 53 / 0 0 10 10
IOLA 17 37 24 51 / 0 0 0 0
PARSONS-KPPF 16 42 24 57 / 0 0 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1154 AM CST MON JAN 21 2013
...UPDATE TO AVIATION...
.DISCUSSION...
TODAY AND TUESDAY...COLD AIR CONTINUES TO TRICKLE INTO THE FORECAST
AREA THIS MORNING AS THE 8Z RAP INDICATES AN AREA OF SURFACE HIGH
PRESSURE STRETCHING FROM THE CENTRAL PLAINS NORTHWESTWARD INTO
CENTRAL CANADA. THIS HIGH PRESSURE IS BRINGING LIGHT NORTHWEST
WINDS...WHICH IS ALLOWING THE COLD AIR TO ADVECT INTO THE AREA.
11-3.9 MICRON SATELLITE SHOWS AN AREA OF STRATUS STRETCHING FROM
KFNB NORTHWESTWARD THROUGH CENTRAL NEBRASKA AND INTO SOUTHWESTERN
SOUTH DAKOTA. OBSERVATIONS FROM CENTRAL NEBRASKA UNDER THIS STRATUS
ARE INDICATING LIGHT SNOW FALL. AS THE STRATUS STRETCHES
SOUTHEASTWARD INTO NORTHEAST KANSAS IT MAY BRING WITH IT A FEW SNOW
FLURRIES...MAINLY NORTH OF INTERSTATE 70. FORECAST SOUNDINGS
THROUGHOUT THE DAY SHOW A MODEST AMOUNT OF UPWARD MOTION IN THE
LOWEST FEW THOUSAND FEET...WHICH WILL AID IN STRATUS DEVELOPMENT AND
WITH THE COLUMN BEING SO COLD IT WILL NOT TAKE MUCH LIFT NOR FURTHER
COOLING TO PRODUCE A FEW FLURRIES. EXPECT SCATTERED OFF-AND-ON
FLURRIES TO REMAIN POSSIBLE THROUGH THE DAYTIME AND OVERNIGHT HOURS
ON MONDAY/MONDAY NIGHT. DUE TO THE CLOUD COVER AND COLD AIR ADVECTION
DO NOT EXPECT TEMPERATURES ON MONDAY TO WARM MUCH...AS THE GOING
HIGH FOR MONDAY WILL BE IN THE LOWER TO MID 20S NORTH OF INTERSTATE
70 AND IN THE LOWER 30S SOUTH OF I-70. DRY AIR WORKS ITS WAY INTO
THE AREA BY MONDAY NIGHT CAUSING THE STRATUS TO MOVE TO THE EAST BY
MONDAY NIGHT ALLOWING SKIES TO CLEAR BY TUESDAY. IT WILL TAKE
ANOTHER DAY TO GET THE COLD AIR OUT OF THE AREA...SO FOR TUESDAY
EXPECTING ONLY A MINOR INCREASE IN TEMPS...AS DAY TIME HIGHS FOR
TUESDAY WILL REACH NO HIGHER THAN THE LOWER TO MID 30S...WITH
POSSIBLY 40 DEGREE TEMPS IN CENTRAL KANSAS.
WEDNESDAY THROUGH SUNDAY...WEDNESDAY WILL BRING A BRIEF BREAK FROM
THE ARCTIC AIR AS WARMER AIR TRIES TO MAKE ITS WAY INTO THE FORECAST
AREA. 925 MB TEMPS GO FROM -10 TO -15 C ON TUESDAY TO AROUND 5 C
WEDNESDAY...WHICH IF MIXED TO THE SURFACE SHOULD BRING TEMPS BACK
INTO THE MID TO UPPER 40S ON WED. PERHAPS AREAS OF CENTRAL AND EAST
CENTRAL KANSAS COULD SEE SOME 50 TO 53 DEGREE TEMPS WED. BY THURSDAY
ANOTHER COLD AIR MASS PLUNGES INTO THE CENTRAL PLAINS CAUSING TEMPS
TO RETURN TO NEAR NORMAL FOR THURSDAY THROUGH SATURDAY...WITH FRIDAY
STRUGGLING TO REACH THE 30S. WARM AIR ADVECTION ON THURSDAY
EVENING/THURSDAY NIGHT WILL BRING INCREASING CLOUDS...AND PERHAPS
SOME VERY LIGHT RAIN IN FAR EAST CENTRAL KANSAS. WITH SURFACE TEMPS
DROPPING NEAR FREEZING AND PERHAPS BELOW FREEZING THURSDAY NIGHT
THERE COULD BE A PERIOD OF VERY LIGHT FREEZING RAIN...BUT THAT
PERIOD SHOULD NOT LAST LONG...NOR IS ANY ACCUMULATION EXPECTED.
A WARM UP FROM THE COLD TEMPS IS EXPECTED BY THE END OF THE WEEKEND
AS FORECAST HIGHS FOR SUNDAY LOOK LIKE THEY WILL REACH THE LOWER TO
POSSIBLY MID 50S AS WARM AIR MOVES BACK INTO THE AREA AND MID LEVEL
RIDGING TAKES OVER. BY EARLY NEXT WEEK WITH INCREASING MID LEVEL
HEIGHTS MOVING OVER THE AREA AND A WESTERLY DOWN SLOPE FLOW THE
LATTER HALF OF THE WEEKEND AND EARLY PART OF NEXT WEEK LOOK FAIRLY
PLEASANT.
JL
&&
.AVIATION...
CLOUD DECK WITH CIGS AROUND 4KFT HAS MOVED OVER THE TAF SITES.
THERE IS AN AREA OF MVFR CIGS IN NORTH CENTRAL KANSAS ON THE SOUTHWEST
FLANK OF THE MAIN CLOUD DECK. THE MVFR CIGS ARE CURRENTLY OVER
KMHK MOVING SOUTHEAST AND MAY MOVE INTO KTOP AND KFOE WITHIN A FEW
HOURS. EXPECT THE MVFR CONDITIONS TO BE POSSIBLE UNTIL AROUND 00Z.
THERE A BAND OF LIGHT SNOW AND FLURRIES WHICH HAS DEVELOPED ACROSS
NORTHEAST KANSAS WHICH WILL CONTINUE THROUGH THIS AFTERNOON AND
EVENING. IT APPEARS IT WILL STAY NORTHEAST OF THE AREA AND NOT EFFECT
ANY TAF SITES...LATER SHIFTS WILL CONTINUE TO MONITOR IN CASE THINGS
DEVELOP FURTHER SOUTH. AFTER 00Z THE VFR CONDITIONS WILL PREVAIL
WITH THE CLOUD DECK SCATTERING OUT AND MOVING OFF TO THE EAST
OVERNIGHT.
SANDERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1144 AM CST MON JAN 21 2013
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
KRSL-KSLN-KCNU WILL BE FLIRTING WITH LOW VFR TO HIGH MVFR CIGS
THIS AFTERNOON-EVENING...AND POSSIBLY THROUGH TONIGHT...AS
SHALLOW COLD AIR TIED TO ARCTIC HIGH PRESSURE ENCROACHES FROM THE
NORTHEAST. FOR NOW PLAYED THE CONSERVATIVE APPROACH...ALTHOUGH IF
LATEST RUC BUFR SOUNDINGS VERIFY CIGS LESS THAN 2000 FT AGL COULD
PREVAIL AS FAR SOUTH AS KHUT AND KICT BY MIDNIGHT. MODELS TEND TO
NOT HANDLE SHALLOW COLD AIRMASSES VERY WELL...SO WILL CONTINUE TO
MONITOR.
ADK
&&
.PREV DISCUSSION... /ISSUED 514 AM CST MON JAN 21 2013/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VFR CONDITIONS ARE EXPECTED ACROSS THE REGION FOR THE NEXT 24 HOURS.
THE ONLY CONCERN WILL BE SOME MID LEVEL CLOUDS IN ERN NEB ASSOCIATED
WITH THE CYCLONIC CURVATURE OVER THE GREAT LAKES. THIS CYCLONIC
CURVATURE WILL LEAD TO THIS MID CLOUD DECK DROPPING SLOWLY
SOUTH-SOUTHEAST THIS AFTERNOON...WITH SOME BKN CEILINGS AROUND 4-6K
FEET NEAR THE KSLN/KCNU AND KRSL TAF SITES. THIS CLOUD DECK WILL BE
SHORT LIVED...BECOMING SCT BY THIS EVENING...AS SUBSIDENCE
ASSOCIATED WITH THE ARCTIC HIGH PRESSURE AREA DROPS INTO IOWA AND
NRN MISSOURI.
KETCHAM
PREV DISCUSSION... /ISSUED 307 AM CST MON JAN 21 2013/
DISCUSSION...
THE MAIN FORECAST CONCERN WILL CONTINUE TO BE TEMPERATURES THROUGH
THE FORECAST.
SYNOPSIS:
A DEEP POTENT TROUGH IS SITUATED ACROSS THE NORTHERN PLAINS THROUGH
THE GREAT LAKES REGION AND THE NORTHEAST. THIS TROUGH IS ASSOCIATED
WITH VERY COLD ARCTIC AIR. TEMPERATURES IN THE NORTHERN PLAINS ARE
WELL BELOW ZERO WITH DANGEROUS WIND CHILL VALUES. AN AMPLIFIED RIDGE
IS LOCATED OVER THE WEST COAST. CLOSER TO HOME...SURFACE HIGH
PRESSURE IS SLIDING INTO THE AREA. THE COLDEST AIR ACROSS THE
CENTRAL PLAINS IS LOCATED OVER IOWA...NEBRASKA...NORTHERN KANSAS AND
NORTHERN MISSOURI. WINDS ARE LIGHT AND OUT OF THE NORTH.
TODAY - WEDNESDAY:
SURFACE HIGH PRESSURE WILL SLIDE EASTWARD OVER MISSOURI WHILE
SURFACE LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES. THE ARCTIC
AIR WILL KEEP TEMPERATURES COLD ACROSS NORTHEASTERN PORTIONS OF
KANSAS...BUT THE SOUTHERLY RETURN FLOW OVER THE WESTERN HALF WILL
ALLOW TEMPERATURES TO WARM TO NEAR NORMAL. THUS...THERE WILL BE A
DRASTIC TEMPERATURE GRADIENT ACROSS THE STATE TODAY.
BECAUSE THE STATE WILL TAKE A GLANCING BLOW WITH THE COLDEST ARCTIC
AIR...TEMPERATURES WILL BE QUICK TO WARM THROUGH MID-WEEK.
TEMPERATURES WILL STEADILY WARM TO ABOVE NORMAL TEMPERATURES THROUGH
WEDNESDAY.
THURSDAY - FRIDAY:
BY THURSDAY THE GUIDANCE INDICATES A WARM FRONT SETTING UP ACROSS
THE SOUTHERN PORTIONS OF THE STATE ASSOCIATED WITH A SURFACE LOW
MOVING SOUTH OUT OF EASTERN COLORADO. THE GFS IS THE MOST BULLISH
IN PRODUCING SOME OVERRUNNING PRECIPITATION FROM THIS FRONT OVER
SOUTHEASTERN KANSAS. THERE IS LITTLE TO NO UPPER LEVEL SUPPORT AND
SOUNDINGS ARE VERY DRY ALOFT WITH SATURATED LOW LEVELS. BECAUSE OF
THIS HAVE KEPT THE PRECIPITATION TYPE TO LIGHT RAIN SHOWERS OR
DRIZZLE. DO NOT THINK THERE IS ENOUGH DEPTH TO HAVE MUCH IN THE WAY
OF RAIN AND HAVE KEPT CHANCES SMALL.
BY THURSDAY AFTERNOON AND INTO FRIDAY THE NEXT UPPER DISTURBANCE
WILL PLUNGE ACROSS THE AREA...PUSHING ANOTHER SHOT OF COLD AIR INTO
THE REGION. TEMPERATURES WILL DROP BRIEFLY BACK TO BELOW NORMAL FOR
THE END OF THE WEEK.
SATURDAY - SUNDAY:
TEMPERATURES WILL AGAIN MODERATE OVER THE WEEKEND AS THE SURFACE
HIGH PRESSURE SLIDES SOUTHEAST SATURDAY AND WARM SOUTHERLY FLOW
RETURNS SATURDAY AFTERNOON AND SUNDAY. SOUTHERLY WINDS WILL ALSO BE
BREEZY AS THE SURFACE LOW PRESSURE DEEPENS AHEAD OF ANOTHER WEAK
UPPER LEVEL DISTURBANCE.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 38 20 48 26 / 0 0 0 0
HUTCHINSON 37 19 47 25 / 0 0 0 0
NEWTON 36 19 44 25 / 0 0 0 0
ELDORADO 36 18 45 25 / 0 0 0 0
WINFIELD-KWLD 39 21 48 26 / 0 0 0 0
RUSSELL 38 16 41 22 / 0 0 0 0
GREAT BEND 40 20 44 25 / 0 0 0 0
SALINA 35 17 41 23 / 0 0 0 0
MCPHERSON 37 18 44 24 / 0 0 0 0
COFFEYVILLE 38 19 45 25 / 0 0 0 0
CHANUTE 35 16 41 23 / 0 0 0 0
IOLA 33 16 39 23 / 0 0 0 0
PARSONS-KPPF 36 15 44 23 / 0 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1126 AM CST MON JAN 21 2013
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1120 AM CST MON JAN 21 2013
AT 12Z MONDAY A 500MB LOW WAS LOCATED NEAR HUDSON BAY AND AN
UPPER LEVEL RIDGE AXIS EXTENDED NORTH ALONG THE WEST COAST OF THE
UNITED STATE INTO SOUTHERN BRITISH COLUMBIA. IN BETWEEN THIS UPPER
RIDGE AND UPPER LOW A NORTHWEST FLOW WAS PRESENT ACROSS THE
CENTRAL UNITED STATES WITH AN UPPER LEVEL TROUGH LOCATED OVER
MINNESOTA. THIS UPPER LEVEL DISTURBANCE WAS LOCATED NEAR THE LEFT
EXIT REGION OF A 300MB JET AND AT THE 500MB LEVEL 120 TO 130 METER
HEIGHT FALLS WERE PRESENT EAST OF THIS UPPER WAVE OVER WISCONSIN
AND NORTHERN INDIANA. A WEDGE OF 850 TO 700MB MOISTURE WAS LOCATED
FROM WESTERN NEBRASKA INTO NORTHEAST KANSAS. THIS WAS LOCATED JUST
NORTH AND EAST OF THE 850MB BAROCLINIC ZONE AND A SURFACE
BOUNDARY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 219 AM CST MON JAN 21 2013
A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION HAS RESULTED
IN AN ARCTIC AIR INTRUSION INTO THE NORTHERN PLAINS EARLY THIS
MORNING. THERE WERE TWO FRONTAL SURGES, ONE THAT PASSED LATE SUNDAY
AFTERNOON THROUGH WESTERN KANSAS, AND A MORE PRONOUNCED FRONT
LOCATED ACROSS CENTRAL NEBRASKA AS OF 2 AM. THIS 2ND COLDER SURGE
WILL NOT MAKE IT THROUGH WESTERN KANSAS TODAY. HOWEVER, A PATCH OF
LOW LEVEL MOISTURE AND LOW CLOUDS, WITH CEILINGS AROUND 1000FT WAS
TRAPPED ACROSS WEST CENTRAL KANSAS NEAR THE SURFACE RIDGE IN THE WAKE
OF THE FIRST FRONT. WEAK LEE TROUGHING IS EXPECTED TO DEVELOP TODAY
AS A SMALL COMPONENT OF MID-LEVEL FLOW ACROSS THE ROCKIES RESULTS
IN PRESSURE FALLS. THIS WOULD TYPICALLY CLEAR THE CLOUDS OUT OF
WESTERN KANSAS. HOWEVER, THERE IS A CHANCE THAT A SHARP LOW-LEVEL
INVERSION WILL DEVELOP AND PERSIST IN SPITE OF THE DAYTIME
HEATING. THE 00Z AND 06Z NAM SHOW NO SIGN OF THIS SCENARIO, WITH
TEMPERATURES IN THE MID 40S AT PLACES LIKE SCOTT CITY AND DIGHTON.
BUT THE 05Z RAP SHOWS A SMALL POCKET OF COLDER AIR, WITH HIGHS
STAYING IN THE MID TO UPPER 30S THERE, WITH 40S FURTHER EAST AND
NEAR 50 IN FAR SOUTHWEST KANSAS. THIS IS A DEPARTURE FROM THE 03Z
RAP WHICH WAS SIMILAR TO THE NAM. SO THE MAIN FORECAST PROBLEM
THIS MORNING IS WHETHER LOW CLOUDS WILL PERSIST ACROSS WEST
CENTRAL KANSAS, ALONG WITH THE COOLER TEMPERATURES. WE OPTED TO GO
GENERALLY WITH A NAM SOLUTION, EXCEPT KEEP TEMPERATURES SEVERAL
DEGREES COOLER WHERE THE RAP IS SHOWING THE LOW LEVEL COLD POOL.
IT IS POSSIBLE THAT GIVEN THE DEVELOPING LOW LEVEL SOUTH TO
SOUTHWEST WINDS THAT THE COLD POOL MAY SHIFT NORTH OF INTERSTATE
70 BY LATE AFTERNOON.
A NORTHWEST TO SOUTHEAST ORIENTED BAROCLINIC ZONE WILL REMAIN ACROSS
THE CENTRAL AND EASTERN PLAINS TONIGHT AS THE AFOREMENTIONED
SECONDARY COLD FRONT STALLS OUT FROM WESTERN NEBRASKA INTO EASTERN
KANSAS. ANY REMAINING LOW CLOUDS SHOULD CLEAR, EXCEPT FOR POSSIBLY A
FEW HIGHER LEVEL CLOUDS. TEMPERATURES SHOULD FALL INTO THE UPPER TEENS
TO LOWER 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CST MON JAN 21 2013
THE UPPER LEVEL LOW PRESSURE SYSTEM CENTERED OVER THE HUDSON BAY
REGION WILL MIGRATE EAST INTO THE CANADIAN MARITIME LATER THIS WEEK
WHICH WILL ALLOW HEIGHTS TO RISE SOMEWHAT OVER THE EASTERN PART OF
THE U.S. FARTHER WEST, A PERSISTENT UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL CONTINUE IN PLACE OVER THE WEST COAST. A SHORTWAVE
TROUGH WILL PLOW THROUGH THE UPPER RIDGE AND MOVE OUT OVER THE
NORTHERN AND CENTRAL PLAINS ON THURSDAY. THE OPERATIONAL GFS IS A
LITTLE SLOWER THAN THE OTHER MODELS WITH THE TIMING OF THIS FEATURE.
THE GFS ENSEMBLE MEMBERS TEND TO BE FASTER THAN THE OPERATIONAL RUN
SO WILL LEAN TOWARD THE EURO AND CANADIAN SOLUTIONS.
A WARMING TREND WILL BE IN PROGRESS FROM TUESDAY INTO WEDNESDAY AS
UPPER LEVEL RIDGING BUILDS INTO THE CENTRAL PLAINS. THE MODELS SHOW
A WEAK FRONTAL BOUNDARY PUSHING SOUTHWESTWARD INTO THE HIGH PLAINS
WEDNESDAY AFTERNOON IN RESPONSE TO A SHORTWAVE TROUGH MOVING THROUGH
THE UPPER MIDWEST AND GREAT LAKES. TEMPERATURES SHOULD BE ABLE TO
RISE INTO THE LOWER 50S AROUND HAYS WITH HIGHS CLIMBING INTO THE MID
60S AT ELKHART. THE NEXT COLD FRONT WILL BE PUSHING SOUTH ACROSS
SOUTHWEST KANSAS ON THURSDAY. THIS WILL DROP TEMPERATURES BACK SOME
ON THURSDAY. ANOTHER SURGE OF EVEN COLDER AIR WILL BE MOVING DOWN
THROUGH THE MIDWEST ON THURSDAY NIGHT BUT THE BULK OF THIS SHOULD
STAY IN EASTERN KANSAS.
THE MODELS SHOW THE UPPER FLOW BECOMING MORE ZONAL ONCE AGAIN BY THE
UPCOMING WEEKEND. DOWNSLOPE FLOW WILL BRING WARMER TEMPERATURES BACK
OUT ACROSS THE HIGH PLAINS WHICH SHOULD ALLOW TEMPERATURES TO WARM
BACK INTO THE 50S AND POSSIBLY THE LOW 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1120 AM CST MON JAN 21 2013
A SURFACE BOUNDARY LOCATED JUST NORTH OF INTERSTATE 70 EARLIER
THIS MORNING WILL REMAIN NEARLY STATIONARY THROUGH THE REMAINDER
OF THE DAY AS AN UPPER LEVEL TROUGH MOVES ACROSS WESTERN GREAT
LAKES. THIS BOUNDARY WILL MOVE SOUTHWEST ACROSS NORTH CENTRAL
KANSAS EARLY TONIGHT WITH BOTH THE GFS AND NAM APPEARING TO BE
GOOD AGREEMENT IN PLACING THIS SURFACE BOUNDARY BETWEEN HAYS AND
DODGE CITY AROUND MIDNIGHT. MODEL SOUNDINGS INDICATING LOW LEVEL
MOISTURE WILL BE LIMITED JUST NORTHEAST OF THIS BOUNDARY SO VFR
CONDITIONS ARE EXPECTED TO CONTINUE THROUGH EARLY TONIGHT. GIVEN
THE LOCATION OF THE SURFACE BOUNDARY TONIGHT WIND SPEEDS ARE
EXPECTED TO DECREASE TO LESS THAN 10KTS BY SUNSET.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 21 48 25 / 0 0 0 0
GCK 44 20 51 24 / 0 0 0 0
EHA 50 26 58 29 / 0 0 0 0
LBL 47 24 54 26 / 0 0 0 0
HYS 38 17 42 21 / 0 0 0 0
P28 40 21 47 27 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...FINCH
LONG TERM...GERARD
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EST MON JAN 21 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 432 PM EST MON JAN 21 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A HIGH AMPLITUDE
PATTERN OVER NAMERICA WITH A RIDGE ALONG THE W COAST THRU AK AND A
DEEP TROF OVER ERN NAMERICA. BEHIND SHORTWAVE THAT HAS PASSED ACROSS
THE AREA...BITTER COLD ARCTIC AIR IS FLOWING OVER THE UPPER GREAT
LAKES. PER 12Z RAOBS...CORE OF THE COLDEST AIR THIS MORNING WAS JUST
UPSTREAM AS KINL SOUNDING SHOWED 850MB TEMP AT A VERY LOW -35C. JUST
N AT CWPL...850MB TEMP WAS AN UNUSUALLY LOW -38C. WITH CAA TODAY...
TEMPS HAVE STRUGGLED TO RISE WITH SUBZERO READINGS THE RULE OVER
ROUGHLY THE W HALF OF UPPER MI JUST INLAND FROM LAKE SUPERIOR. AT
KIWD...TEMP HAS ONLY REACHED -11F. OVER THE E...TEMPS HAVE HELD IN
THE SINGLE DIGITS ABOVE ZERO. WIND CHILLS REMAIN GENERALLY IN THE
-20 TO -35F RANGE OVER THE W HALF AND -10 TO -20F E. WITH EXTREME
INSTABILITY OVER THE LAKE...LES OBVIOUSLY CONTINUES FOR MAINLY THE
SNOWBELTS FAVORED BY NW WINDS. AS EXPECTED...WITH VERY COLD AIR
ELIMINATING THE DGZ...SNOWFLAKE SIZE HAS BEEN VERY SMALL. THE SMALL
SNOWFLAKES ARE VERY EFFECTIVE AT REDUCING VIS...SO WHERE LES IS
OCCURRING...WHITE-OUTS ARE COMMON. SMALL FLAKES ARE LIMITING
ACCUMULATIONS WITH MOST SPOTTER/COOP REPORTS INDICATING MOSTLY
1-3IN/12HR SNOWFALL RATES. EXCEPTION IS OVER THE FAR NE FCST
AREA...THOUGH REPORTS ARE DIFFICULT TO OBTAIN. ONE REPORT AT UPPER
TAHQUAMENON FALLS WHICH HAS BEEN UNDER A NEARLY STEADY DOMINANT BAND
INDICATED ABOUT 7 INCHES OF SNOW SINCE EARLY THIS MORNING. STRONG
CONVERGENCE ZONE OWING TO LAKE INDUCED TROFFING AND STRENGTHENED BY
STRONG LAND BREEZES IS LIKELY ALLOWING ENOUGH LAKE MODERATION TO
PUSH DGZ UP INTO AT LEAST A PORTION OF THE CONVECTIVE LAYER.
SO...SOME RATHER SIGNIFICANT SNOW ACCUMULATIONS HAVE PROBABLY
OCCURRED OVER THE LAST 12-18HRS OVER SOME PORTIONS OF ERN ALGER/NRN
SCHOOLCRAFT/NRN LUCE COUNTIES.
CORE OF ARCTIC AIR WILL DROP ACROSS THE AREA TONIGHT. IN THE WAKE OF
THE SHORTWAVE THAT PASSED TODAY AND WITHOUT ANY ADDITIONAL
SHORTWAVES APPROACHING...FCST SOUNDINGS SHOW A GRADUAL DECREASE IN
CONVECTIVE/MOIST LAYER...ESPECIALLY DURING THE DAY TUE AS HEIGHTS
BEGIN TO RISE. SO...TONIGHT WILL ESSENTIALLY BE JUST A CONTINUATION
OF WHAT HAS BEEN HAPPENING TODAY. OVER THE W...EXPECT MOSTLY 1-3IN
ACCUMULATIONS TONIGHT...THOUGH LOCALIZED 4 INCH AMOUNTS COULD OCCUR
BTWN KIWD AND THE VCNTY OF THE PORCUPINE MTNS DUE TO ENHANCED
CONVERGENCE FROM STRENGTHENING LAND BREEZE OFF NW WI. POOR VIS WILL
BE THE BIGGER STORY WITH THE SNOW AS WHITE-OUTS WILL CONTINUE TO BE
COMMON DUE TO THE VERY SMALL SNOWFLAKE SIZE. TO THE E...
STRENGTHENING LAND BREEZES WILL AGAIN STRENGTHEN THE CONVERGENCE
ZONE OVER SCNTRL AND ERN LAKE SUPERIOR INTO PORTIONS OF
ALGER/LUCE/NRN SCHOOLCRAFT COUNTIES. MOST GUIDANCE INDICATES A SHARP
SFC TROF RATHER THAN MESOLOW DEVELOPMENT...SO THERE IS MORE
CONFIDENCE IN MAINTAINING MDT/HVY SNOW STREAMING ONSHORE IN THAT
AREA THRU THE NIGHT RATHER THAN HAVING SNOW SHIFT N AND POSSIBLY
MOSTLY OFFSHORE IF A MESOLOW DEVELOPED. WHERE HEAVIEST SNOW IS MOST
PERSISTENT...MAY SEE UPWARDS OF 8 INCHES TONIGHT.
OTHER OBVIOUS STORY IS THE COLD. GIVEN HOW LOW 850MB TEMPS ARE...
SFC TEMPS WOULD TANK TO READINGS NOT SEEN IN UPPER MI FOR MANY YEARS
IF WINDS WERE TO DROP OFF TO CALM TONIGHT. HOWEVER...SINCE WINDS
STAY UP...TEMPS WON`T FALL SIGNIFICANTLY TONIGHT. OVER ROUGHLY THE W
HALF INLAND FROM LES...TEENS BLO ZERO SHOULD BE THE RULE WITH A FEW
SPOTS POSSIBLY FALLING TO AROUND -20F. ELSEWHERE...EXPECT SINGLE
DIGITS BLO ZERO. ONLY LOCATIONS THAT PROBABLY WON`T FALL BLO ZERO
WILL BE RIGHT ALONG THE SHORE E OF MUNISING. WINDS SHOULD STAY UP
NEAR THE 10MPH THRESHOLD FOR WIND CHILL ADVY...SO ADVYS WILL REMAIN
UP FOR -25 TO -35F WIND CHILLS. WILL BE FLIRTING WITH WARNING
CRITERIA (-35F OR LWR) TOWARD THE WI BORDER W OF KIMT.
AIR MASS BEGINS TO SLOWLY MODERATE TUE...BUT STILL REMAINS COLD
ENOUGH TO KEEP DGZ OUT OF THE CONVECTIVE LAYER. SO...MORE FINE VIS
RESTRICTING LES IS EXPECTED. SMALL FLAKES COMBINED WITH HEIGHT RISES
AND DECREASING CONVECTIVE/MOIST LAYER WILL CONTINUE TO KEEP
ACCUMULATIONS ON THE LIGHT SIDE...ESPECIALLY OVER THE W. WILL
PROBABLY BEGIN TO SEE MORE GAPS/SEPARATION BTWN LES BANDS AS
LOW-LEVEL DRY AIR MAY BEGIN TO MAKE MORE OF AN IMPACT. OVER THE
E...MDT/HVY LES IN THE MORNING SHOULD ALSO BEGIN TO DIMINISH GIVEN
LARGER SCALE NEGATIVES PREVIOUSLY MENTIONED. TEMPS SHOULD RISE ABOVE
0F IN MOST AREAS...THOUGH OVER THE W HALF...SOME READINGS WILL
LIKELY FALL JUST SHORT OF 0F.
AS FOR HEADLINES...WILL BE ADDING MENOMINEE/DELTA TO WIND CHILL ADVY
TONIGHT/TUE MORNING AND WILL BE EXTENDING LES WARNING FOR
ALGER/LUCE/NRN SCHOOLCRAFT THRU TUE AFTN.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 432 PM EST MON JAN 21 2013
GIVEN THE PERSISTENT 500MB LOW SET UP THROUGH WEDNESDAY...EXPECT THE
COLD WEATHER TO LINGER THROUGH AT LEAST WEDNESDAY MORNING. LES WILL
CONTINUE TO BE A NUISANCE THROUGH WEDNESDAY EVENING.
TUESDAY NIGHT AND WEDNESDAY...
DOUBLE DIGIT BELOW ZERO READINGS WILL BE THE RULE AGAIN TUESDAY
NIGHT. PERSISTENT W TO WNW FLOW OVER THE WARM WATERS OF LAKE
SUPERIOR...AND SLIGHTLY WARMER TEMPS JUST ABOVE THE SFC /850MB
WARMING FROM -27/-24C TO AROUND -23/-22C OVERNIGHT BASED OFF THE
ECMWF/GFS/. WITH DIMINISHING WINDS OVERNIGHT...WIND CHILLS READINGS
WILL BE LESS IMPRESSIVE THAN THE LAST COUPLE OF NIGHTS...BOTTOMING
OUT NEAR -25 TO -28F NEAR IWD...WITH THE COLDEST VALUES PRIOR TO
MIDNIGHT. THE DGZ WILL PUSH FROM THE SFC UP THROUGH 900MB...AND
LINGER AT THOSE LEVELS THROUGH WEDNESDAY. WITH PLENTY OF LINGERING
MOISTURE...EXPECT SOME MODERATE ACCUMULATIONS TUESDAY NIGHT OVER THE
KEWEENAW PENINSULA AND NEAR AND E OF GRAND MARAIS...TRANSITIONING TO
ALL AREAS NEAR LAKE SUPERIOR ON BY LATE WEDNESDAY WITH ENHANCEMENT
FROM THE EXITING SFC LOW SWITCHING WINDS TO A W/NW DIRECTION AND A
PASSING WAVE ALOFT. ALSO EXPECT MODERATING TEMPS WEDNESDAY...AS
850MB TEMPS REMAIN NEAR -21C. AN ADDITIONAL 4-7IN OF SNOW MAY BE
POSSIBLE ACROSS PORTIONS OF THE KEWEENAW PENINSULA...WITH LESSER
AMOUNTS ELSEWHERE NEAR LAKE SUPERIOR.
WEDNESDAY NIGHT...
THE MODERATE LAKE TO 700 AND 850MB TEMP DIFFERENCES WILL REMAIN. THE
LATEST INDICATIONS ARE THAT THE BEST CONVERGENT WINDS N AT THE SFC
WILL BE FROM BIG BAY THROUGH MQT/SAW AND MUNISING EARLY IN THE
EVENING...BEFORE LIGHT AND MORE VARIABLE WINDS ATTEMPT TAKE HOLD
OVERNIGHT. MODEL CONSISTENCY PAST LATE EVENING IS STILL A BIT FLAKY
AT THIS POINT...SO WILL HOLD OFF ON GOING ADDING TOO MUCH DETAIL TO
THE EXPECTED SNOW AMOUNTS EXCEPT TO HIGHLIGHT N CENTRAL AND AREAS
FROM IWD TO ROCKLAND.
TOTAL SNOWFALL FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT /36HRS/
WILL LIKELY TOP OUT IN THE 7 TO 10IN RANGE E OF MUNISING TO
WHITEFISH PT...AND FROM ONTONAGON UP THROUGH TWIN LAKES AND
PAINESDALE. ADVISORIES...ALTHOUGH NOT POSTED AT THIS TIME DUE TO
CURRENT HEADLINES AND DISTANCE OUT...WILL PROBABLY BE
NEEDED...PARTICULARLY IF THE LAKE INDUCED MESO LOW DEVELOPS OVER FAR
EAST AS HAS BEEN SHOWN OVER THE PAST DAY OR SO. MODERATE TO HEAVY
SNOW WOULD BE LIKELY OVER LUCE AND POSSIBLY FAR E ALGER COUNTY.
THURSDAY THROUGH NEXT MONDAY...
WILE THE 21/06 GFS DIVERGED SIGNIFICANTLY FROM THE THE
NAM/ECMWF/CANADIAN DIVERGE FROM THE GFS THURSDAY...WITH ITS SOLUTION
BEING ROUGHLY 12HRS SLOWER WITH THE NEXT SHORTWAVE OVER SW CANADA.
THE 21/12Z GFS SEEMS TO HAVE CORRECTED THIS ISSUE FOR THE MOST
PART...WITH LESS DEVIATION BETWEEN SOLUTIONS THROUGH THE PASSAGE OF
THE TROUGH OVER THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY.
KEPT EXTENDED POPS IN THE CHANCE RANGE AT THE HIGHEST FOR NOW GIVEN
THE OVERALL LIGHTER FLOW. LOW TEMPS WILL BRIEFLY RETURN TO BELOW
ZERO VALUES FRIDAY NIGHT OVER THE INTERIOR W HALF...BEFORE SLOWLY
RISING. HAVE HIGH TEMPS RISING TO AROUND FREEZING MONDAY AFTERNOON
AS 850MB TEMPS RISE INTO THE SINGLE DIGITS BELOW 0C.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM EST MON JAN 21 2013
DIFFERENT FORECAST OVER THE NEXT 24 HRS FOR EACH OF THE THREE TAF
SITES AS ARCTIC AIR SPILLS OVER LAKE SUPERIOR AND INTO UPPER MI.
KIWD...LES SNOW BAND IS ANCHORING ITSELF OVER THE TERMINAL AS
CONVERGENCE INCREASES BETWEEN NW WINDS OVER LAKE SUPERIOR AND WSW
WINDS ON A LAND BREEZE NEAR IWD. EXCEPT VIS UNDER AIRFIELD MINS INTO
THIS EVENING BEFORE WINDS BEGIN TO BACK MORE TO THE WEST. TOUGH TO
SAY WHEN THAT TIMING WILL BE ATTM. ONE ADDITIONAL ITEM TO NOTE IS
THAT IF THE LAND BREEZE IS WEAK ENOUGH...THE LES BAND MAY NOT MOVE
OUT QUICKLY AND CAUSE 1/4SM VIS TO LAST WELL INTO THE NIGHT.
KCMX...VLIFR/UNDER AIRFIELD MINS EXPECTED WITH VIS THROUGH THE
AFTERNOON. WIDESPREAD LAKE EFFECT SHSN AND BLSN WITH NW WINDS WILL
KEEP VIS DOWN TO 1/4SM...THOUGH A FEW SHORT BREAKS OF 1/2SM ARE
POSSIBLE. WINDS TURN MORE TO THE NORTHWEST THIS EVENING AND SHOULD
DISRUPT LES ENOUGH TO BRING VIS BACK TO 1/2SM.
KSAW...VFR CONDITIONS EXPECTED AS DOWNSLOPE W TO NW WINDS WILL ERODE
LAKE EFFECT CLOUDS AS THEY APPROACH THE TERMINAL. SOME BLOWING SNOW
IS POSSIBLE WITH STRONGER WINDS THIS AFTERNOON. WINDS WILL TURN A
LITTLE MORE NORTHWESTERLY THIS EVENING AND ALLOW FOR A LITTLE MORE
MOISTURE...AND POSSIBLY A FEW SNOW SHOWERS...TO AFFECT THE SITE
OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EST MON JAN 21 2013
WITH VERY COLD ARCTIC AIR FLOWING OVER LAKE SUPERIOR...NW WINDS WILL
STAY IN THE 20-30KT RANGE TONIGHT. EXPECT SOME GALE FORCE GUSTS OVER
THE CNTRL PORTION OF THE LAKE JUST W OF SFC TROFFING OVER ERN LAKE
SUPERIOR. WINDS WILL ONLY DIMINISH SLIGHTLY INTO MOSTLY THE 15-25KT
RANGE TUE. VERY COLD AIR WILL COMBINE WITH WINDS/WAVES TO PRODUCE
PERIODS OF HEAVY FREEZING SPRAY TONIGHT/TUE. HEAVY FREEZING SPRAY
WILL CONTINUE THROUGH WEDNESDAY EVENING...MAINLY ACROSS THE S
SHORELINE OF LAKE SUPERIOR. WITH HIGH PRESSURE PUSHING IN THURSDAY
WIND WILL BECOME LIGHT AND VARIABLE...WITH LITTLE WAVES AND A SLIGHT
WARM UP /LIMITING THE POTENTIAL FOR FREEZING SPRAY/. N-NW WILL
INCREASE FRIDAY...WITH A FEW GUSTS NEARING 20-25KTS. OTHERWISE LIGHT
WINDS LESS THAN 20KTS CAN BE EXPECTED FROM THURSDAY THROUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR
MIZ001>003-009-084.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ004-
005-010-011.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ012-
013.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ240>251-263>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY
FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...TK
MARINE...ROLFSON/KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1245 PM EST MON JAN 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EST MON JAN 21 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
E AND CENTRAL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF THE W
COAST. COLDEST AIRMASS OF THE SEASON HAS FLOODED INTO THE UPR LKS IN
THE NW LLVL FLOW WITH H85 TEMPS AS LO AS -25C OVER THE WRN CWA. 00Z
H85 TEMP WAS AS LO AS -30C AT YPL. THE PASSAGE OF THIS COLD AIRMASS
OVER THE RELATIVELY WARM WATERS OF LK SUP HAS RESULTED IN NMRS LK
EFFECT SHSN. BUT LLVL FLOW HAS BACKED TO MORE WNW IN ADVANCE OF NEXT
SHRTWV DROPPING SEWD THRU NW ONTARIO TOWARD ISLE ROYALE. IN CONCERT
WITH NEAR SFC WSW WIND ENHANCED BY LAND BREEZE FLOW OF SUB ZERO
TEMPS TOWARD WARMER LK SUP...THIS WSHFT IS CONFINING THE BULK OF THE
LES TO AREAS OVER THE W MAINLY N OF THE PORCUPINE MTNS THRU THE
KEWEENAW AND TO AREAS NEAR LK SUP E OF PICTURED ROCKS LAKESHORE. ONE
IMPACT OF THE VERY COLD AIRMASS IS THE DGZ HAS NEARLY DISAPPEARED AT
LEAST OVER THE W...RESULTING IN VERY FINE SN FLAKES THAT EFFICIENTLY
REDUCE THE VSBY WHILE LIMITING SN ACCUMS. SKIES ARE GENERALLY
CLR-PCLDY OVER AREAS TO THE S OF THE LES...WHICH HAS ALLOWED TEMPS
TO FALL BLO ZERO. THE WIND CHILL EARLY THIS MRNG HAS DROPPED AS LO
AS -25F AT IWD. TO THE NW...THERE IS AN AREA OF CLDS ASSOCIATED WITH
THE DIGGING SHRTWV AND FAIRLY DEEP MSTR DEPICTED ON THE 00Z YPL
RAOB. THERE ARE EVEN SOME REPORTS OF -SN IN ONTARIO JUST N OF THE MN
BORDER DESPITE PWATS OF 0.06 INCH REPORTED AT INL/YPL.
TODAY...AS SHRTWV/ACCOMPANYING DEEP LYR QVECTOR CNVGC/MSTR JUST TO
THE NW DIG SEWD ACROSS THE CWA THIS MRNG...EXPECT LES INTENSITY TO
INCRS SOMEWHAT WHILE NEAR -30C H85 TEMPS ARE DRAWN INTO WRN UPR MI.
ALTHOUGH DEEPENING CONVECTIVE DEPTH/MSTR TO ABV 10K FT AS SHOWN ON
FCST SDNGS WOULD NORMALLY BE A CONCERN FOR VERY HEAVY LES...NEAR
ABSENCE OF DGZ WITH SUCH COLD H85 TEMPS INDICATES SN FLAKES WL BE
VERY SMALL...ESPECIALLY OVER THE W WITH SHORTER FETCH/LESS
MODIFICATION OF THE COLD/DRY AIRMASS. ONE ADVANTAGE FOR HEAVIER SHSN
WOULD BE INCRSG LLVL CNVGC. SINCE THE LLVL FLOW WL VEER MORE TO THE
NW WITH PASSAGE OF SHRTWV...EXPECT LES BANDS TO DRIFT BACK TO THE S.
THIS VEERING FLOW OFF THE SFC WL LIKELY RESULT IN SHARPER LLVL CNVGC
OVER THE W BTWN LAND BREEZE FLOWS OFF WI/INTERIOR WRN UPR MI AND
OVER THE E WITH THESE FLOWS OFF CNTRL UPR MI AND SE ONTARIO/ERN UPR
MI. GENERAL CONSENSUS OF HIER RES MODELS SHOWS THE BACK CHC FOR THE
SHARPER CNVGC WL BE OVER THE W FM THE PORCUPINE MTNS TO NEAR TWIN
LAKES IN CNTRL HOUGHTON COUNTY AND IN AREAS E OF MUNISING AND AS FAR
S AS ABOUT HIGHWAY M-28. THESE HI RES MODELS ALL SHOW THE SHARPEST
CNVGC/HIER QPF OVER THE ERN CWA...AND SOME INDICATE THE HEAVIER SHSN
WL PUSH FARTHER INLAND THAN M-28. ON THE OTHER HAND...SOME OF THE
MODELS INDICATE A LK INDUCED VORTEX MAY DVLP NEAR GRAND MARAIS AND
LIMIT THE INLAND SPREAD OF THE SHSN. AS FOR SN AMOUNTS...OLD LES
CHART INDICATES SN FALL OF 5-9 INCHES/12 HRS GIVEN EXPECTED
CONDITIONS. BUT RECENT EXPERIENCE SUGS THE NEAR ABSENCE OF DGZ CUTS
THESE TOTALS BY ABOUT HALF. WITH SHARPER LLVL CNVGC/MORE LK
MODERATION THAT WOULD MAINTAIN HIER LLVL TEMPS MORE CONDUCIVE TO
BIGGER SN FLAKES...BEST CHC TO GET THE HIER LES CHART FCST NUMBERS
WOULD BE OVER THE ERN CWA. GOING LES WRNG FOR THIS AREA APPEARS ON
TRACK. IF THE SN BANDS IMPACT SRN SCHOOLCRAFT COUNTY AS SOME OF THE
HIER RES MODELS SHOW...AN ADVY MIGHT BE NECESSARY FOR THAT AREA. BUT
GIVEN UNCERTAINTY ON THIS SCENARIO...HELD OFF FOR NOW. CURRENT
WINTER WX ADVYS OVER THE W ALSO SEEM WELL PLACED. WITH H85 TEMPS
FCST TO FALL AT LEAST CLOSE TO -30C THRU THE DAY...EXPECT SFC TEMPS
OVER MUCH OF THE W TO REMAIN BLO ZERO. ALTHOUGH WIND CHILLS AT MOST
PLACES EXCEPT FOR IWD ARE UNDER ADVY CRITERIA...ARRIVAL OF COLDER
AIR/INCRSG WINDS WITH LLVL DESTABILIZATION JUSTIFIES CONTINUING
ADVYS OVER THE INTERIOR W HALF EVEN IF THERE IS MORE LK MODERATION
WITH VEERING LLVL FLOW. THESE WINDS WL ALSO AID BLSN/REDUCING VSBYS
AND JUSTIFY HEADLINES EVEN IF SN AMOUNTS ARE SUB HEADLINE.
TNGT...WITH DNVA/LARGER SCALE SUBSIDENCE IN THE WAKE OF DEPARTING
SHRTWV THAT BEGINS THIS AFTN...EXPECT CONVECTIVE LYR/MSTR DEPTH TO
SLOWLY SINK. H925 WINDS ARE ALSO FCST TO VEER A BIT MORE TOWARD THE
NW...SO SHSN OVER THE W MIGHT SINK TOWARD IWD. CONSIDERING THE
AGREEMENT ON THE MODELS SHOWING HIER QPF OVER IWD WITH THIS VEERING
FLOW...OPTED TO INCLUDE GOGEBIC COUNTY IN WINTER WX ADVY IN LIEU OF
JUST THE WIND CHILL HEADLINE. ALTHOUGH H85 TEMPS FCST AS LO AS -30C
OVER PORTIONS OF THE W INDICATE WELL BLO ZERO LO TEMPS...TENDED TO
BUMP UP FCST MIN TEMPS A FEW DEGREES WITH MORE LK MODERATION IN
VEERED FLOW. BUT STILL EXPECT WIND CHILLS AS LO AS -25F TO -35F WITH
CAD MAINTAINING SOME MIXING...SO MAINTAINED GOING WIND CHILL ADVYS.
SHARPEST LLVL CNVGC/SOME LK MODERATION OF ARCTIC CHILL REMAINS OVER
THE E. GOING LK EFFECT SN WRNG THRU 12Z TUE IN THAT AREA LOOKS ON
TRACK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 508 AM EST MON JAN 21 2013
AT 12Z TUE...THE COLDEST 850MB TEMPS AS LOW AS -32C WILL BE OVER THE
CWA...BUT WILL PUSH E THROUGH THE DAY AS THE UPPER TROUGH OVER MUCH
OF THE CONUS SHIFTS SLOWLY E. WITH A SFC RIDGE PUSHING IN FROM THE
SW AND A LAKE INDUCED SFC TROUGH STRETCHING INTO ERN LAKE SUPERIOR
FROM THE SE...WINDS WILL BE OUT OF THE NW WITH RESULTING NW WIND
LES. THESE COLD TEMPS WILL KEEP HIGHS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO...BUT WITH THE PRESSURE GRADIENT RELAXING THROUGH THE
DAY...WIND CHILL HEADLINES WILL NOT BE NEEDED AFTER THE MORNING OURS
TUE.
TUE NIGHT WILL BE QUITE COLD WITH LOWS TO -2 OVER MUCH OF INTERIOR
WRN UPPER MI...BUT WINDS WILL BE LIGHT SO AT THIS POINT WIND CHILL
HEADLINES DO NOT APPEAR TO BE NECESSARY. A SHORTWAVE TROUGH WILL
APPROACH THE CWA WED NIGHT AND MOVE THROUGH ON WED...BUT ANY
SYNOPTIC PRECIP WILL REMAIN OUT OF THE CWA. THE SHORTWAVE WILL ACT
TO ENHANCE THE SFC TROUGHING OVER LAKE SUPERIOR /POSSIBLY INTO A
WEAK LOW OVER THE ERN LAKE/...WHICH MODELS INDICATE WOULD CAUSE LOW
LEVEL WINDS TO BECOME MORE WLY AND CYCLONIC OVER MUCH OF LAKE
SUPERIOR. IF THE WINDS DO ALIGN AS INDICATED...A MORE DOMINANT LES
BAND WOULD PROBABLY RESULT OVER THE KEWEENAW AND POSSIBLY INTO THE
FAR NERN CWA /FAR NRN ALGER AND LUCE COUNTIES/. 850MB TEMPS TUE
NIGHT LOOK TO BE IN THE -20C TO -25C RANGE...SO SNOW TO LIQUID
RATIOS SHOULD BE A BIT BETTER THAN WHAT WE HAVE SEEN IN THE LAST DAY
OR SO WITH THE REALLY COLD TEMPS OVER THE CWA. COULD SEE SEVERAL
INCHES OF SNOW IN THE IMPACTED AREAS IF THESE DETAILS COME TOGETHER.
LOW LEVEL WINDS BECOME MORE NWLY ON WED AS THE SHORTWAVE PASSES.
CONDITIONS WILL BE MORE THAN SUFFICIENT FOR MODERATE TO POSSIBLY
HEAVY LES GIVEN LAKE INDUCED EQUILIBRIUM LEVELS OVER 10KFT PER MODEL
SOUNDINGS.
CONDITIONS WILL BECOME INCREASINGLY HOSTILE FOR LES WED NIGHT AS A
SFC RIDGE MOVES IN FROM THE NW...SO WILL HAVE DECREASING POPS INTO
THU. MODELS DISAGREE MORE ON A SHORTWAVE POSSIBLY MOVING S OF THE
CWA THU INTO THU NIGHT...BUT CHANCE POPS NEAR LAKE SUPERIOR AS IS IN
THE GOING FORECAST SEEM REASONABLE SO WILL LEAVE THAT IDEA IN THERE.
850MB TEMPS WARM INTO THE NEGATIVE TEENS BY LATE THU AS THE UPPER
TROUGH PUSHES FARTHER TO THE E. MODELS AGREE WITH BRINGING ANOTHER
SHORTWAVE THROUGH ON FRI...BUT DISAGREE ON THE STRENGTH.
AGAIN...CHANCE POPS AT LEAST IN NW WIND SNOWBELTS SEEMS REASONABLE
FOR FRI. UPPER AND SFC RIDGING PUSHES IN FROM THE W THROUGH THE REST
OF THE FORECAST PERIOD...WITH WARMING LOW LEVEL TEMPS...DECREASING
CHANCES FOR LES AND NO MAJOR SYSTEM EXPECTED TO MOVE THROUGH. SIMPLY
USED A CONSENSUS OF MODELS FOR THIS TIME PERIOD AND FOCUSED MORE ON
THE SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM EST MON JAN 21 2013
DIFFERENT FORECAST OVER THE NEXT 24 HRS FOR EACH OF THE THREE TAF
SITES AS ARCTIC AIR SPILLS OVER LAKE SUPERIOR AND INTO UPPER MI.
KIWD...LES SNOW BAND IS ANCHORING ITSELF OVER THE TERMINAL AS
CONVERGENCE INCREASES BETWEEN NW WINDS OVER LAKE SUPERIOR AND WSW
WINDS ON A LAND BREEZE NEAR IWD. EXCEPT VIS UNDER AIRFIELD MINS INTO
THIS EVENING BEFORE WINDS BEGIN TO BACK MORE TO THE WEST. TOUGH TO
SAY WHEN THAT TIMING WILL BE ATTM. ONE ADDITIONAL ITEM TO NOTE IS
THAT IF THE LAND BREEZE IS WEAK ENOUGH...THE LES BAND MAY NOT MOVE
OUT QUICKLY AND CAUSE 1/4SM VIS TO LAST WELL INTO THE NIGHT.
KCMX...VLIFR/UNDER AIRFIELD MINS EXPECTED WITH VIS THROUGH THE
AFTERNOON. WIDESPREAD LAKE EFFECT SHSN AND BLSN WITH NW WINDS WILL
KEEP VIS DOWN TO 1/4SM...THOUGH A FEW SHORT BREAKS OF 1/2SM ARE
POSSIBLE. WINDS TURN MORE TO THE NORTHWEST THIS EVENING AND SHOULD
DISRUPT LES ENOUGH TO BRING VIS BACK TO 1/2SM.
KSAW...VFR CONDITIONS EXPECTED AS DOWNSLOPE W TO NW WINDS WILL ERODE
LAKE EFFECT CLOUDS AS THEY APPROACH THE TERMINAL. SOME BLOWING SNOW
IS POSSIBLE WITH STRONGER WINDS THIS AFTERNOON. WINDS WILL TURN A
LITTLE MORE NORTHWESTERLY THIS EVENING AND ALLOW FOR A LITTLE MORE
MOISTURE...AND POSSIBLY A FEW SNOW SHOWERS...TO AFFECT THE SITE
OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EST MON JAN 21 2013
EXPECT NW WINDS 15 TO 30 KT THRU TONIGHT TO ADVECT ARCTIC AIR OVER
THE LAKE AND CAUSE PERIODS OF HEAVY FREEZING SPRAY. LIGHTER WINDS AT
TIMES INTO THIS AFTERNOON NEAR A LO PRES TROF OVER EASTERN LAKE
SUPERIOR MAY BRING A BREAK FROM THE HEAVY FREEZING SPRAY. FREEZING
SPRAY WILL CONTINUE AT TIMES THROUGH WEDNESDAY. NO GALES ARE EXPECTED
THROUGH THE FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR
MIZ001>003-009-084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ TUESDAY FOR MIZ004-
005-010-011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TK
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
503 PM EST MON JAN 21 2013
.SYNOPSIS...
PERIODS OF LIGHT SNOW WILL TAPER OFF THIS EVENING AS A WEAK AREA
OF LOW PRESSURE TRACKS OUT OF THE REGION. COLDER AIR WILL ARRIVE
ON GUSTY WEST TO NORTHWEST WINDS LATER TONIGHT...WHICH WILL ALLOW LAKE
EFFECT SNOWS TO DEVELOP. THIS ACTIVITY WILL DIMINISH ON THURSDAY
AS HIGH PRESSURE BRIEFLY MOVES INTO THE AREA. OUTSIDE OF THE LAKE
EFFECT SNOW...PARTLY TO MOSTLY CLOUDY SKIES AND SCATTERED SNOW
SHOWERS OR FLURRIES ARE EXPECTED.
&&
.NEAR TERM /THROUGH TUESDAY/...
450 PM UPDATE...
HAVE HOISTED A QUICK WINTER WX ADVISORY FROM THE CENTRAL SOUTHERN
TIER NORTHEAST THROUGH THE FINGER LAKES AND UPPER SUSQUEHANNA
VALLEY REGIONS AS A NOTABLE LOW-LEVEL CONVERGENT SIGNATURE AS
NOTED IN THE LATEST MSLP FIELD IS LEADING TO AN IMPRESSIVE LINEAR
SNOW BAND. HAVE RECEIVED MULTIPLE 3 TO 5 INCH REPORTS ACROSS THE
CENTRAL FINGER LAKES REGION AND BASED ON LATEST RR FORECASTS FROM
THE SPC MESO PAGE...WE EXPECT THIS LOW-LEVEL CONVERGENCE REGION
TO REMAIN IN PLACE FOR A FEW MORE HRS BEFORE FINALLY WINDING DOWN
AFTER 00Z. BASED ON THIS...HAVE INCREASED SNOWFALL TOTALS ACROSS
THE REGION WITH 4 TO 6 INCHES POSSIBLE FOR AREAS IN CLOSE PROXIMITY
TO THE LOW-LEVEL CONVERGENT MAXIMUM. NO OTHER CHANGES NEEDED AT
THIS TIME.
PREVIOUS NEAR TERM DISCUSSION...
FCST AREA WILL REMAIN UNDER NW FLOW ALOFT WITH A FEW EMBEDDED
S/WV`S TRAVERSING THE RGN. 1ST ONE IS CRNTLY AFFECTING THE FCST
AREA WITH AREAS OF LGT SNOW...AND 2ND ONE IS FCST TO MOVE INTO THE
RGN ON WED NGT. A MEANDERING FNTL BNDRY AND LES INFLUENCES WILL
CONTINUE TO MODULATE THE SHSN ACTIVITY ACRS THE FCST AREA INTO MID
WEEK.
LATER TNGT AS THE 1ST WAVE DEPARTS...LOW LVL FLOW WILL BCM WRLY AND
FOCUS LES EFFECTS INTO NRN ONEIDA COUNTY AS 850 TEMPS DROPS TO ARND
-20C. LOW LVL 270 FLOW BCMS ALIGNED BY 06Z. HIGH INVERSION LVL
(10K FT)...ALIGNED FLOW AND GOOD SNOW GROWTH PROFILE. CRNT FCST
HAS ACCUMS OF 6-10 INCHES PRIMARILY NEAR THE OSWEGO/LEWIS COUNTY
BORDER. BOTTOM LINE IS THAT SRN PERIPHERY OF THIS BAND IS XPCTD TO
BE OVER NRN ONEIDA WITH LOW END WARNING ACCUMS. THIS BAND IS FCST
TO DROP SWD LATE TUE AFTN INTO NRN ONON/MAD/SRN ONEIDA/NRN OTSEGO.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
LES BAND XPCTD TO MEANDER ACRS FAVORED 290-300 FLOW REGIONS INTO
WED MRNG...WHICH MAY BE ENHANCED BY LOW LVL CONVERGENCE ASSCD WITH
SAGGING ARCTIC BNDRY. THIS ACTIVITY SHUD WEAKEN BY WED AFTN.
PROFILES STILL LOOKING GOOD DURING THIS TIME FRAME...AS INVERSION
LVL REMAINS HIGH AT 9-10 K FT AND LOW LVL FLOW REMAINS ALIGNED
ARND 300 DEG...THEN THE INVERSION LOWERS AND FLOW WEAKENS BY WED
AFTN. INITIAL THOUGHTS ARE THAT WE`LL NEED LES ADVISORIES FOR THIS
TIME PERIOD. WE`LL DEFER ON THE POTNL HEADLINES ATTM...AND LET THE
EVNG/MID SHIFTS RE-ASSESS. HAVE MENTIONED POTNL IN THE UPDATED
HWO. OUSIDE THE MAIN LES AREAS...SLGT CHC TO LOW CHC POPS...WITH
POTNL FOR LAKE ERIE ACTIVITY TO CUT ACRS PORTIONS OF THE SRN TIER
AND NE PA.
CONCERNING WIND CHILLS...GIVEN CRNT FCST TEMPS AND WINDS WE DO NOT
SHOW ANY VALUES BLO -15 UNTIL TMRW NGT ACRS ONEIDA COUNTY. PSBL
THAT A FEW OTHER LOCATIONS COULD APRCH VALUES. LATER SHIFTS CAN
RE-EVALUATE THIS.
ON WED XPCT LES ACTIVITY TO DIMINISH BUT APRCHNG S/WV COULD RESULT
IN DVLPMNT OF MORE --SHSN AS THE DAY PROGRESSES SO WE CONTINUE
WITH CHC POPS MOST LOCATIONS. BEST CHC FOR A DRY DAY WILL BE
THURSDAY AS SFC HIGH IS XPCTD TO CREST OVER THE RGN LATE IN THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED.
INITIALLY A SOUTHERN STREAM SYSTEM WILL TRACK THROUGH THE MID
ATLANTIC REGION ON FRIDAY. THE ECMWF/CANADIAN IS MUCH FASTER THAN
THE GFS, LEANED TOWARD THE ECMWF ENSEMBLE WHICH IS A GOOD
COMPROMISE. THURSDAY NIGHT BACKED OFF ON POPS TO JUST CHC THEN
CHC/LIKELY ON FRIDAY WITH LIKELY POPS ACROSS THE SOUTHERN TIER AND
NE PA. MODELS INDICATE ALL SNOW WITH NO HINT OF ANY WARM LAYER.
BEHIND THIS WAVE THE UPPER LEVEL TROF WILL AMPLIFY OVER THE
NORTHEAST MAKING FOR A COLD WEEKEND WITH SCATTERED SNOW SHOWERS IN
NORTH/NORTHWEST FLOW. BY SUNDAY/MONDAY, UPPER LEVEL HEIGHTS RISE
WITH THE AIRMASS EXPECTED TO MODIFY UNDER SOUTHWEST FLOW.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
AN UPPER LEVEL DISTURBANCE AND ITS ASSOCIATED WEAK SFC FEATURE
WILL TRACK ACROSS CENTRAL PA LATE THIS AFTERNOON THROUGH THE EARLY
EVENING. THIS SYSTEM WILL PRODUCE WIDESPREAD MVFR CONDITIONS IN LIGHT
SNOW ACROSS ALL OF THE TERMINALS THIS AFTERNOON THROUGH THE EARLY
EVENING PERIOD. ACROSS THE SOUTHERN TERMINALS IFR CONDITIONS ARE
POSSIBLE BETWEEN 18Z-00Z, BUT MOST LIKELY AT KBGM/KAVP. BEHIND
THIS WAVE NORTHWEST FLOW WILL DEVELOP KEEPING PRIMARILY MVFR
CONDITIONS ACROSS THE REGION THROUGH 06Z WITH SCATTERED FLURRIES
AND SNOW SHOWERS. AFTER 06Z CONDITIONS WILL BE PRIMARILY VFR WITH
SOUTHWEST WINDS DEVELOPING. THE LAKE EFFECT SNOW IS EXPECTED TO
REMAIN NORTH OF THE KRME/KSYR TERMINALS THROUGH 18Z BUT AFTER 18Z
IT IS EXPECTED TO AFFECT THE AIRPORTS WITH IFR CONDITIONS LIKELY.
SOUTHWEST WINDS AROUND 5 KNOTS OT LIGHT AND VARIABLE BECOMING
NORTHWEST THIS EVENING AROUND 10 KNOTS SHIFTING TO THE SOUTHWEST
TOWARD DAYBREAK AND INCREASING TO 12-15 KNOTS WITH GUSTS AROUND 25
KNOTS.
.OUTLOOK...
TUE NIGHT THRU WED...MVFR/IFR IN SNOW SHOWERS FOR KRME/KSYR
OTHERWISE PRIMARILY VFR.
THURSDAY/THURSDAY NIGHT...PRIMARILY VFR.
FRI... IFR CONDITIONS POSSIBLE IN SNOW.
FRIDAY NIGHT/SATURDAY...MVFR SNOW SHOWERS RESTRICTIONS LIKELY FOR
CENTRAL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NYZ009-
015>018-022-023-025-036-037-044.
LAKE EFFECT SNOW WARNING FROM 1 AM TUESDAY TO 1 PM EST
WEDNESDAY FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...CMG
SHORT TERM...
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
242 PM MST MON JAN 21 2013
.DISCUSSION...21Z SURFACE ANALYSIS HAD WARM FRONT FROM CENTRAL MT
INTO WESTERN NE. LIFT ALONG 140KT JET STREAK ON COLD SIDE OF WARM
FRONT CONTINUING TO PRODUCE -SN OVER WESTERN SD PER KUDX RADAR.
12Z GUIDANCE AS WELL AS 18Z RAP SHOW ACTIVITY WANING AND SLOWLY
MOVING EAST TONIGHT. MOST ACTIVITY SHOULD EXIT CWA BY 12Z TUESDAY.
ACCUMULATIONS WILL CONTINUE TO BE MINOR. TEMPERATURES NEAR
GUIDANCE LOOK REASONABLE.
TUESDAY...UPPER RIDGE BUILDS EAST INTO THE ROCKIES AS SURFACE WARM
FRONT WORKS ACROSS WESTERN SD. HOW FAR EAST IT GOES IT THE MAIN
QUESTION...BUT IT SHOULD AT LEAST MAKE IT TO A K2WX TO KVTN LINE.
BEHIND IT TEMPERATURES SHOULD REACH WELL INTO THE 30S TO LOWER 40S
GIVEN FORECAST LOWER TROPOSPHERIC PROFILES.
WEDNESDAY...UPPER RIDGE MOVES OVER THE NORTHERN PLAINS AND
DEAMPLIFIES AS SHORTWAVE TROUGHS MOVES INTO THE NORTHERN ROCKIES.
INITIAL TROUGH/COOL FRONT WILL SLIDE INTO THE CWA. TEMPERATURES
SHOULD ROCKET INTO THE 40S OVER WY/HIGHER ELEVATIONS...BUT AS AN
EASTERLY COMPONENT TO THE SURFACE WIND DEVELOPS ON THE SD PLAINS
BY AFTERNOON...EXPECT TEMPERATURES RISES TO BE HALTED MAINLY IN
THE 20S. ST/BR MAY DEVELOP WEDNESDAY NIGHT GIVEN WEAK UPSLOPE FLOW
AHEAD OF NEXT FRONT FOR THURSDAY.
EXTENDED...A FAST MOVING CLIPPER SYSTEM WILL MOVE THROUGH THE NRN
PLAINS ON THURSDAY...BRINGING GUSTY NORTHWEST WINDS ALONG WITH
CHANCES FOR PRECIP MAINLY OVER THE NRN CWA. RIDGE OVER THE WRN CONUS
WILL THEN SLOWLY SHIFT EAST...BRINGING MILD AND DRY CONDITIONS FOR
THE WEEKEND. MODELS START TO DIVERGE ON A SOLUTION TO START NEXT
WEEK THOUGH OVERALL PATTERN REMAINS UNSETTLED...SO WILL LEAVE LOW
POPS IN FOR NOW.
&&
.AVIATION...18Z TAF UPDATE
LIGHT SNOW OVER THE WESTERN SD PLAINS INTO EXTREME NERN WY WILL
CONTINUE INTO THIS EVENING BRINGING MAINLY MVFR CIGS/VIS...THOUGH
LCL IFR VIS WILL BE POSSIBLE. -SN WILL SLOWLY SHIFT EAST EARLY
TUESDAY MORNING WITH CIGS IMPROVING TO VFR.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM...77
AVIATION...77
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1220 PM CST MON JAN 21 2013
.AVIATION...
VFR CONDITIONS WITH LIGHT WINDS EXPECTED AS A WEAK SURFACE HIGH
PRESSURE RIDGE NOSES INTO THE AREA THIS AFTERNOON...WEAK SURFACE
TROUGHING WILL FOLLOW TONIGHT INTO TUESDAY. LOW CLOUD DECK
EXPECTED TO DEVELOP SOUTHEAST OF THE AREA EARLY TUESDAY. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 511 AM CST MON JAN 21 2013/
AVIATION...
VFR CONDITIONS MAY BRIEFLY BE INTERRUPTED AT LBB AFTER SUNRISE AS
LOW CLOUDS ATTEMPT TO EXPAND SOUTHEAST FROM EAST OF CLOVIS. FOR NOW
HAVE KEPT THE PREVIOUS TEMPO SCT010 TO ADDRESS THIS SCENARIO AS
CONFIDENCE IN ANY PROLONGED WINDOW OF MVFR/IFR STRATUS IS VERY
LOW. OTHERWISE...EXPECT LIGHT NELY WINDS TO VEER SELY BY LATE DAY
BEHIND COOL HIGH PRESSURE.
PREV DISCUSSION... /ISSUED 444 AM CST MON JAN 21 2013/
SHORT TERM...
TROUBLE-FREE FROPA OVERNIGHT MAY PROVE MORE COMPLICATED IN THE
COMING HOURS WITHIN THE POST-FRONTAL REGIME. SPECIFICALLY...A
SHALLOW FRONTAL INVERSION WAS SLOWLY MOISTENING IN THE WRN TX
PANHANDLE AS EVIDENCE BY SPOTTY LOW CLOUDS EMERGING ON THE 11-3.9
IR CHANNEL. THIS TRAPPED LAYER OF MOISTURE CONTINUES TO BE
OVERDONE BY THE GFS...WHEREAS THE NAM APPEARS CLOSER TO REALITY.
THE HRRR MEANWHILE IS STILL BEHIND THE CURVE AS IT STRUGGLES TO
CAPTURE THE STRATUS BANK ANCHORED FARTHER NORTH IN THE COMANCHE
NAT`L GRASSLAND.
PATTERN RECOGNITION IN SUCH SETUPS TENDS TO FAVOR AN INCREASE IN
STRATUS /PARTICULARLY AROUND SUNRISE/ AS DEWPOINT DEPRESSIONS ARE
AT THEIR LOWEST. EVEN WITH DRIER 2M DEWPOINTS USHERING ACROSS THE
TX PANHANDLE...THE CRITICAL CLOUD LAYER IS ABOUT 1K FEET ALOFT
ALONG THE FRONTAL INVERSION AND FAR REMOVED FROM THE SHALLOW DRY
AIR BELOW. THE 00Z AND 06Z NAM RUNS SUPPORT THIS IDEA OF
INCREASING STRATUS BY 12-15Z...SO HAVE RAMPED UP CLOUD COVER ON
THE CAPROCK THRU 15Z BEFORE SCATTERING OUT THEREAFTER.
EVEN IF LOW CLOUDS FAIL TO MATERIALIZE...BELIEVE HI TEMPS WILL BE
STUNTED MORE THAN MODELS ADVERTISE AS THE 850MB THERMAL TROUGH
WILL BE SITUATED DIRECTLY OVER THE CWA BY PEAK HEATING COINCIDENT
WITH A SURFACE PRESSURE RIDGE. LACK OF SWLY WINDS AND DEEPER
MIXING IN THIS SETUP DOESN`T BODE WELL FOR TOO MUCH OF DIURNAL
TEMP CURVE...SO HAVE UNDERCUT MOS GUIDANCE MOST PLACES ESPECIALLY
OFF THE CAPROCK WHERE NELY WINDS PREVAIL MOST OF THE AFTERNOON.
LONG TERM...
TEMPERATURES WILL RAPIDLY WARM UP FOR TUESDAY AND WEDNESDAY.
THURSDAY REMAINS PROBLEMATIC AS THE GFS REMAINS INSISTENT ON
BRINGING ANOTHER FRONT INTO THE NORTHEASTERN HALF OF THE FORECAST
AREA BEFORE STALLING IT OUT. ALL OTHER NWP GUIDANCE INDICATES THE
FRONT TO STALL OUT WELL NORTH OF THE REGION WITH WESTERLY FLOW
THROUGH THE DAY THURSDAY. BECAUSE OF THESE DIFFERENCES...SOME
LOCATIONS HAVE BEEN GIVEN HIGH TEMPERATURES ON THURSDAY ANYWHERE
FROM THE LOW 60S TO UPPER 70S. WITH THE TREND IN MOST OF THE
MODELS TO BE WESTERLY SURFACE WIND DEVELOPING THROUGH THE
DAY...INCREASED TEMPERATURES FROM PREVIOUS FORECAST A BIT BUT DID
NOT GO QUITE AS HIGH AS THE NAM IS PREDICTING. THE GFS IS STILL
TRYING TO DEVELOP PRECIPITATION WITH THE FRONTAL PASSAGE BUT THIS
APPEARS TO BE OVERDONE AS THIS MODEL HAS SURFACE MOISTURE POOLING
ALONG THE FRONT WHILE ALL OTHER MODELS DO NOT REFLECT THIS
ALSO CAN SEE SOME ISSUES ON FRIDAY DEPENDING ON WHETHER THE FRONT
IS ALREADY THROUGH THE REGION SUCH AS THE ECMWF OR CANADIAN ARE
SHOWING...OR WHETHER IT PUSHES THROUGH DURING THE DAY ON FRIDAY AS
THE GFS IS SHOWING. TEMPERATURES WILL START TO WARM FOR THE
UPCOMING WEEKEND AS SOUTHERLY FLOW RAPIDLY DEVELOPS AT THE SURFACE
ACROSS THE REGION AND SOUTHWESTERLY FLOW ALOFT HELPS TO DEVELOP
THE LEE SURFACE TROF ONCE AGAIN.
JORDAN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 24 62 27 68 33 / 0 0 0 0 0
TULIA 24 63 29 68 33 / 0 0 0 0 0
PLAINVIEW 25 63 29 68 33 / 0 0 0 0 0
LEVELLAND 26 63 29 69 34 / 0 0 0 0 0
LUBBOCK 26 63 30 69 34 / 0 0 0 0 0
DENVER CITY 30 63 33 69 35 / 0 0 0 0 0
BROWNFIELD 28 63 33 71 34 / 0 0 0 0 0
CHILDRESS 27 62 33 68 39 / 0 0 0 0 0
SPUR 28 63 38 71 41 / 0 0 0 0 0
ASPERMONT 30 65 40 72 45 / 0 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
448 PM CST MON JAN 21 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE STRETCHING SOUTHEAST ACROSS THE GREAT PLAINS EARLY THIS
AFTERNOON. WEAK SHORTWAVE IS DROPPING ACROSS THE STATE WHICH IS
CONTRIBUTING TO A STRATO-CU FIELD...WITH THE HELP FROM STEEP LOW
LEVEL LAPSE RATES. SCT FLURRIES ARE FALLING OUT OF THIS STRATO-CU
DECK FROM THE SOUTHERN FOX VALLEY TO CENTRAL AND NORTH-CENTRAL
WISCONSIN. TEMPERATURES AND WIND CHILL READINGS HAVE HARDLY BUDGED
SINCE EARLIER THIS MORNING...AND PLENTY OF 30-35 BELOW WIND CHILL
READINGS REMAIN OVER NORTH-CENTRAL WISCONSIN. FORECAST CONCERNS
INCLUDE CLOUD TRENDS AND WIND CHILL HEADLINES.
TONIGHT...ARCTIC HIGH PRESSURE WILL BE BUILDING SOUTHEAST ACROSS THE
NORTHERN MISSISSIPPI VALLEY THROUGH THE NIGHT. SHORTWAVE TROUGH
OVERHEAD WILL BE EXITING THE REGION BY LATE THIS AFTERNOON OR EARLY
THIS EVENING. WITH LOSS OF A SMALL DIURNAL COMPONENT...AM COUNTING
ON INCREASING SUBSIDENCE TO HELP GRADUALLY DISSIPATE MUCH OF THE
STRATO-CU FIELD OVER CENTRAL AND EAST-CENTRAL WISCONSIN THIS
EVENING. NORTH-CENTRAL WISCONSIN MAY NOT CLEAR OUT MUCH AT ALL...AS
LOW LEVEL WINDS VEER AROUND SLIGHTLY TO THE NORTHWEST AND PUSH LAKE
EFFECT CLOUDS SOUTHEAST BENEATH A FAIRLY SHARP INVERSION. TOO COLD
FOR MUCH ACCUMS...BUT POSSIBLY UP TO AN INCH OVER THE FAR NORTHERN
PART OF THE COUNTY. THE CLEARING SKIES WILL HELP TEMPS BECOME
COLDER TONIGHT COMPARED TO LAST NIGHT...BUT THIS WILL BE OFFSET BY A
WEAKENING PRESSURE GRADIENT AND WIND SPEEDS. APPARENT TEMP GRIDS
SHOW WIND CHILLS FALLING ONLY A FEW DEGREES THIS EVENING...BUT
READINGS HAVE REMAINED STEADY ACROSS NORTH-CENTRAL WISCONSIN
TODAY...SO WILL NOT TAKE MUCH OF A FALL TO REACH WARNING CRITERIA.
AFTER COORDINATING WITH SURROUNDING OFFICES...WILL ISSUE A WIND
CHILL WARNING WHERE AM MOST CONFIDENT IN REACHING CRITERIA...FROM
LINCOLN AND LANGLADE TO VILAS AND FOREST COUNTY STARTING THIS
EVENING AND GOING THROUGH MID-MORNING TUESDAY.
TUESDAY...ARCTIC HIGH PRESSURE WILL BE SLIDING TO THE OHIO VALLEY.
CORE OF THE COLDEST AIR WILL BE SHIFTING TO THE NORTHEAST...ALONG
WITH THE HIGHER LOW LEVEL HUMIDITY. BUT WILL ALREADY BE OFF TO A
VERY COLD START SO TEMPS WILL NOT BE SIGNIFICANTLY WARMER THAN
TODAYS READINGS. WITH WINDS BACKING TO THE WEST...SHOULD SEE MORE
SUNSHINE THAN TODAY. WINDS WILL ALSO BE LIGHTER...AND WIND CHILL
READINGS SHOULD BE IMPROVING RAPIDLY BY MID TO LATE MORNING. WILL
CONTINUE TO RUN WIND CHILL HEADLINES TO 18Z. HIGHS RANGING FROM 5
BELOW NORTH TO ABOUT 4 ABOVE NEAR LAKE MICHIGAN.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. PRIMARY ISSUE
CONTINUES TO BE THE DURATION OF THE COLD AIR THIS WEEK FOLLOWED BY
A CLIPPER TYPE SYSTEM LATER THIS WEEK.
COLD AIR INTRUSION CONTINUES TUESDAY NIGHT WITH THE LIKELY CHANCE
OF ADDITIONAL WIND CHILL HEADLINES ACROSS AT LEAST THE NORTH HALF
OF THE FORECAST AREA. A WEAK TROUGH IS PROGGED DROPS OVER THE GREAT
LAKES REGION IN THE NORTHWEST FLOW WED INTO WED EVENING...FOLLOWED
WITH ANOTHER BRIEF PERIOD OF CAA INTO THURSDAY MORNING.
THIS BIT LONGER DURATION OF COLDER AIR INTO WEDNESDAY NIGHT
PRECEDES THE TREND OF SLOWING DOWN THE CLIPPER TYPE SYSTEM FOR
LATER THURSDAY AND INTO FRIDAY MORNING...WHICH IS SUPPORTED BY THE
LAST FEW MODEL RUNS. WOULD NOT BE SURPRISED WITH LATER RUNS
INDICATING THE CLIPPER WILL LINGER MORE INTO FRIDAY AS THIS
CLIPPER SYSTEM PHASES WITH A SOUTHERN STREAM SYSTEM. COULD SEE A
FEW INCHES OF SNOW BY FRIDAY OVER MOST LOCATIONS.
AFTER A BRIEF PERIOD OF CAA IN THE WAKE OF THE CLIPPER...GRADUALLY
MODERATING TEMPERATURES TO NEAR SEASONAL NORMS STILL EXPECTED FOR
THE WEEKEND AND INTO MONDAY.
WAA FOR SUNDAY ALONG WITH A H850 TROUGH TRACKING OVER THE AREA
MAY WILL PROVIDE A CHANCE FOR LIGHT SNOW OR FLURRIES.
LAKE EFFECT POTENTIAL. THE CHANCE FOR LAKE EFFECT SNOWS INCREASE
TOWARD WEDNESDAY NIGHT OVER FAR NORTHERN WISCONSIN AS THE SHORT
WAVE TROUGH SWINGS THROUGH AND WINDS TURN BRIEFLY NORTHWEST AGAIN.
NORTHWEST WINDS WILL NOT LAST LONG AS THE COLD SURFACE HIGH
DROPS INTO THE REGION. BUT WINDS BEGIN TO TURN MORE EASTERLY
THURSDAY INTO THURSDAY NIGHT TO INCREASE THE POTENTIAL OF MORE
SNOW SHOWERS ALONG LAKE MICHIGAN..ESPECIALLY AS THE WEAK CLIPPER
TRACKS THROUGH TO PROVIDE SOME LIFT. COULD HAVE HIGHER SNOW
AMOUNTS ALONG THE LAKE MICHIGAN SHORELINE THURSDAY NIGHT INTO
FRIDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE. VFR CONDITIONS EXPECTED AS
ARCTIC AIR DOMINATES THE AREA. THE ONLY EXCEPTION WL BE NR THE
UPPER MICHIGAN BORDER WHERE CLDS OFF LAKE SUPERIOR WL DROP CIGS
INTO MVFR CAT AT TIMES.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ012-013-
020>022-030-031-035>040-045-048>050-073-074.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR WIZ005-010-011-018-
019.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
300 PM CST MON JAN 21 2013
.SHORT TERM...TONIGHT THROUGH THURSDAY
300 PM CST MON JAN 21 2013
MAIN FORECAST CONCERNS ARE ON HOW QUICK THE CURRENT ARCTIC AIRMASS
MODIFIES...IF SNOW CAN FORM OFF OF LAKE PEPIN AGAIN TONIGHT...AND
LIGHT SNOW CHANCES TUESDAY NIGHT THROUGH THURSDAY.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO BRITISH
COLUMBIA...WHILE DEEP TROUGHING WAS IN PLACE OVER SOUTHEAST CANADA
INTO THE WESTERN GREAT LAKES REGION. UNDER THIS DEEP TROUGHING...
850MB TEMPS WERE -25C AT MPX...-27C AT GRB AND -35C AT INL PER 12Z
SOUNDINGS...OR 2 TO 2.5 STANDARD DEVIATIONS BELOW NORMAL. THESE COLD
READINGS...COMBINED WITH A NORTHWEST BREEZE RESULTING FROM A TIGHT
PRESSURE GRADIENT BETWEEN LOW PRESSURE IN NORTHERN LAKE HURON AND
ARCTIC HIGH PRESSURE IN THE DAKOTAS...HAVE RESULTED IN TEMPERATURES
ONLY SLOWLY RISING TODAY. STILL...WITH MOST OF THE AREA EXCLUDING
NORTH OF HIGHWAY 10 HAVING BARE GROUND...AND SUNSHINE THROUGH SOME
CONVECTIVELY INDUCED STRATOCUMULUS UNDER THE 850MB THERMAL TROUGH
HAS ALLOWED TEMPERATURES SOUTH OF HIGHWAY 10 TO CLIMB TO OR SLIGHTLY
ABOVE ZERO. WIND CHILLS ARE STILL 15 TO 30 BELOW...THOUGH. TO THE
WEST...RAP ANALYSIS SHOWED A 140KT JET AT THE TROPOPAUSE DROPPING
DOWN THROUGH THE EASTERN DAKOTAS. ALONG AND WEST OF THIS UPPER JET
STREAK...MID AND HIGH CLOUDS ARE PRESENT...REFLECTING THE UPPER
LEVEL MOISTURE SEEN ON WATER VAPOR. 850MB TEMPS WARM QUITE A BIT TOO
WEST OF THE UPPER JET...AS EXPECTED THROUGH THE THERMAL WIND
RELATIONSHIP...CLIMBING FROM -23C AT BIS TO -14C AT UNR PER 12Z
SOUNDINGS.
TONIGHT AND TUESDAY...THE UPPER LEVEL PATTERN IS NOT FORECAST TO
CHANGE MUCH OVER THE NEXT 24 HOURS...WITH PERHAPS ONLY A SLIGHT
EASTWARD PROGRESSION TO THE WESTERN RIDGE AND DEEP TROUGH.
HOWEVER...THIS PROGRESSION WILL BE ENOUGH TO SLIDE THE ARCTIC HIGH
OVER THE DAKOTAS INTO THE FORECAST AREA BY 00Z WEDNESDAY...ALONG
WITH THE UPPER JET STREAK AND THE MID/HIGH CLOUDS ACCOMPANYING THE
JET STREAK. OF INTEREST TONIGHT IS TO SEE IF ANOTHER NARROW BAND CAN
FORM OFF LAKE PEPIN...WHICH WILL DEPEND ON IF THE LAKE WAS ABLE TO
FREEZE OVER. LAST NIGHT...WITH THE ARCTIC AIR FLOWING IN...A NARROW
BAND FORMED WITH VISIBILITIES LESS THAN 1/4 MILE. SEE OUR NEWS STORY
ON OUR WEBSITE FOR MORE ABOUT THE BAND. THE 20.12Z HIRES-ARW
YESTERDAY SHOWED THE BAND HAPPENING LAST NIGHT...THOUGH THE THOUGHT
AT THE TIME WAS THAT THE ENTIRE MISSISSIPPI RIVER SYSTEM WAS FROZEN
OVER. THE 21.06Z/12Z HIRES-ARW SHOW A BAND FORMING AGAIN TONIGHT...
AND GIVEN THAT IT HAS STAYED BREEZY TODAY TO HELP PREVENT ICE
FORMATION ON LAKE PEPIN...HAVE THUS INCLUDED SOME SMALL
PRECIPITATION CHANCES FOR THE BAND BETWEEN 06-15Z TUESDAY. OTHERWISE
TEMPERATURES AND WIND CHILLS ARE THE MAIN ISSUE. THE 925MB THERMAL
TROUGH REMAINS IN PLACE TONIGHT WITH READINGS OF -24 TO -28C...
COLDEST NORTH OF I-94. SINCE WE MAINTAIN A BREEZE MOST OF THE
NIGHT...THE BOUNDARY LAYER SHOULD REMAIN MIXED AT LEAST UP TO 950MB
IF NOT TO THAT 925MB LEVEL...RESULTING IN LOWS BETWEEN 5 AND 15
BELOW. COLDEST READINGS WOULD OCCUR NORTH OF HIGHWAY 10 WHERE A
LITTLE SNOW PACK EXISTS. ON TUESDAY...GRADUAL WARMING TAKES PLACE TO
THE 925MB TEMPS WITH THE SHIFT EAST OF THE DEEP TROUGHING...CLIMBING
TO -19 TO -23C BY 21Z. THUS...WE SHOULD SEE HIGHS JUST A FEW DEGREES
WARMER THAN THOSE TODAY UNDER MOSTLY SUNNY SKIES.
TUESDAY NIGHT AND WEDNESDAY...THERE HAS BEEN A TREND TO SLOW UP THE
PATTERN MORE DURING THIS TIME PERIOD COMPARED TO PREVIOUS
FORECASTS...AND TO SOME DEGREE DRAMATICALLY. THE REASON FOR THE SLOW
DOWN IS THAT MODELS HAVE FOCUSED ON A POTENT SHORTWAVE DROPPING
SOUTH OUT OF NORTHERN MANITOBA. ALL MODELS HAVE IT DIGGING DOWN INTO
UPPER MICHIGAN AND EVEN NORTHERN WISCONSIN BY 00Z THURSDAY. THIS
HOLDS UP THE RIDGE OVER THE WESTERN U.S. FROM PUSHING EAST. IN
ADDITION...WE END UP NOW SEEING ANOTHER ARCTIC HIGH DROPPING DOWN
INTO THE RED RIVER VALLEY OF NORTH DAKOTA...WITH A COLD FRONTAL
PASSAGE COMING THROUGH THE FORECAST AREA AHEAD OF IT DURING THE DAY
WEDNESDAY. PRIOR TO THIS FRONTAL PASSAGE...THE 21.12Z CANADIAN/UKMET
AND 21.00Z ECMWF DEPICT A BAND OF LIGHT QPF COMING INTO THE FORECAST
AREA FROM THE WEST...REACHING ABOUT THE MISSISSIPPI RIVER SOUTH OF
I-90 BY 12Z WEDNESDAY. THIS BAND IS THAT SAME BAND OF MID/HIGH
CLOUDS TRAVERSING THE PLAINS WHICH ENDS UP MARCHING EAST. GIVEN THAT
THERE ARE OBSERVATIONS OF SNOW UNDER THE BAND...HAVE MAINTAINED
FLURRIES AND INCLUDED 20 PERCENT CHANCES. THE BAND DOES WEAKEN OVER
TIME AS THAT POTENT SHORTWAVE DIGS SOUTH...AND AFTER 18Z ANY
FLURRIES ASSOCIATED WITH IT SHOULD HAVE SHIFTED OFF TO THE
SOUTHEAST. SOME FLURRY ACTIVITY COULD OCCUR NORTH OF I-94 IN THE
AFTERNOON WITH THE SHORTWAVE. WITH MORE CLOUDS TUESDAY NIGHT...
EXPECT A WARMER NIGHT...AND IN FACT TEMPERATURES COULD RISE AFTER
MIDNIGHT AS 925MB TEMPS WARM WITH THE SOUTHWEST WINDS AHEAD OF THE
FRONT. THE WARMER NIGHT PLUS 925MB TEMPS OF -12 TO -18C AT 18Z
WEDNESDAY SHOULD YIELD HIGHS IN THE TEENS TO LOW 20S IN MOST
LOCATIONS.
WEDNESDAY NIGHT AND THURSDAY...GOOD AGREEMENT EXISTS AMONG THE
21.12Z GFS/ECMWF/UKMET/CANADIAN OF TAKING A POTENT SHORTWAVE TROUGH
COMING INTO THE PACIFIC NORTHWEST AT 00Z THURSDAY ACROSS THE
NORTHERN ROCKIES...THEN INTO THE DAKOTAS BY 00Z FRIDAY. AGAIN...THIS
IS QUITE A BIT SLOWER THAN YESTERDAYS FORECAST. THE NAM IS AN
OUTLIER BY ALMOST BRINGING IT INTO MN...BUT IS NOT DEEP ENOUGH
DIGGING THE WEDNESDAY SHORTWAVE. GIVEN THE SLOWER TREND...THE SPREAD
OF DPVA AND WARM ADVECTION / FRONTOGENESIS INDUCED SNOW DOWNSTREAM
IS SLOWER TOO...WITH DRY CONDITIONS NOW INDICATED THROUGH AT LEAST
18Z THURSDAY FOR THE FORECAST AREA. AFTER 18Z...MODELS CONTINUE TO
BACK OFF ON THE AMOUNT OF PRECIPITATION...PRIMARILY BECAUSE THIS
POTENT SHORTWAVE TROUGH IS MOISTURE STARVED. ALL THE BETTER MOISTURE
IS TIED UP WITH A SOUTHERN STREAM-TYPE SHORTWAVE AND SURFACE LOW
PRESSURE SYSTEM OVER THE SOUTHERN PLAINS. THERE STILL IS SOME LIGHT
SNOW INDICATED OVER THE AREA PER THE 27.12Z ECMWF...BUT THE 27.12Z
GFS IS DRY. THEREFORE...HAVE LOWERED CHANCES ABOUT 10 PERCENT. IF
TRENDS CONTINUE...LIKELY THURSDAY WILL END UP DRY WITH JUST SOME
INCREASING MID AND HIGH CLOUDS. DUE TO THE DEEPER WEDNESDAY
SHORTWAVE TROUGH...HAVE LOWERED LOWS A FEW DEGREES WEDNESDAY NIGHT
TO ACCOUNT FOR MORE CANADIAN AIR ADVECTING IN. 925MB TEMPS ACTUALLY
FALL TO AROUND -20C BY 12Z THURSDAY. WIND CHILLS LOOK TO STAY OUT OF
ADVISORY CRITERIA THIS TIME...THOUGH. WITH MORE CANADIAN AIR IN
PLACE ON THURSDAY...ENDING UP ALSO COOLING THURSDAY JUST
SLIGHTLY...BUT HAVING BARE GROUND AND A LITTLE MORE SUN WILL HELP
COUNTERACT THE COLDER 850MB TEMPS.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
300 PM CST MON JAN 21 2013
21.12Z ECMWF/CANADIAN/GFS AND ECMWF ENSEMBLES STILL IN PRETTY GOOD
AGREEMENT FOR THE LONG TERM FORECAST AND SHOW A SIMILAR SOLUTION TO
YESTERDAY. THERE ARE TWO MAIN DIFFERENCES:
1. THE THURSDAY NIGHT DEAL WITH RESPECT TO PRECIPITATION IS NOW
LOOKING A LOT LESS THAN WHAT THE 20.12Z ECMWF HAD...SINCE WE ARE
ONLY INFLUENCED BY THAT POTENT SHORTWAVE DROPPING THROUGH THE AREA
FRIDAY MORNING. ALL OF THE MOISTURE AGAIN IS TIED UP WITH THE
SOUTHERN STREAM SYSTEM...SO AT MOST WE END UP WITH A FEW HUNDREDTHS
OF LIQUID EQUIVALENT. GIVEN THE POTENT NATURE OF THE TROUGH...
DEFINITELY MAINTAINED SOME 30-40 PERCENT CHANCES OF PRECIPITATION
FOR THURSDAY NIGHT. FUTURE FORECASTS MAY HAVE TO RAISE THESE SINCE
IT IS LOOKING LIKE MOST LOCATIONS SHOULD BE ABLE TO GET A
HUNDREDTH. ALSO ADDED SOME LOW CHANCES OF PRECIPITATION TO FRIDAY
BEING UNDER THE SHORTWAVE TROUGH TO ALLOW FOR A MORE CONVECTIVE
SITUATION.
2. UPPER RIDGING IS STILL PROGGED TO BUILD TOWARDS THE AREA FOR THE
WEEKEND...BRINGING TEMPERATURES BACK UP TO NEAR AND EVEN ABOVE
NORMAL FOR SUNDAY. HOWEVER...NOW THERE ARE INDICATIONS OF A
SHORTWAVE TROUGH MOVING THROUGH THIS RIDGING...IMPACTING THE AREA ON
SUNDAY. FOLLOWED THE CONSENSUS AND ADDED 20 PERCENT CHANCES OF SNOW
TO THE FORECAST. THIS TROUGH ALSO HOLDS BACK SOME OF THE WARMING
THAT WOULD HAVE OCCURRED UNDER THE LOW LEVEL SOUTHWEST FLOW.
HEADING INTO MONDAY...MORE TROUGHING IS SUGGESTED ALONG THE WEST
COAST OF THE U.S....BUT UNCERTAINTY EXISTS ON WHETHER IT SPLITS INTO
TWO AS SHOWN BY THE 21.12Z ECMWF OR STAYS TOGETHER PER 21.12Z GFS.
21.12Z ECMWF ENSEMBLE MEAN SEEMS TO SUGGEST BOTH SCENARIOS ARE
PLAUSIBLE. EITHER SCENARIO AT LEAST FOR MONDAY DOES NOT RESULT IN
ANY PRECIPITATION FOR US...WITH WARMING COMING BACK INTO THE AREA IN
THE WAKE OF THE SUNDAY SHORTWAVE TROUGH. READINGS LOOK LIKE THEY
SHOULD GET BACK ABOVE FREEZING FOR HIGHS.
&&
.AVIATION...THIS AFTERNOON THROUGH TUESDAY
1130 AM CST MON JAN 21 2013
MAIN PROBLEM IS THE APPARENT OVER-REPORTING OF BKN-OVC CIGS BY THE
ASOS/AWOS SYSTEMS AROUND THE AREA LATE THIS MORNING...WHICH SEEMS
MORE COMMON IN VERY COLD AIRMASSES. PERUSAL OF WEB CAMS AND LOOK OUT
THE OFFICE WINDOWS/AROUND THE LOCAL HORIZON SHOWS PLENTY OF SUNSHINE
AND CLOUDS MORE SCT AT BOTH KRST/KLSE LATE THIS MORNING. THUS
CARRIED SCT MVFR CLOUDS THIS AFTERNOON AT BOTH KRST/KLSE. MODELS
HANG ONTO SOME LOWER LEVEL MOISTURE NEAR 925MB TONIGHT INTO TUE
MORNING...AND CONTINUED SCT MVFR CLOUDS THRU TONIGHT/TUE MORNING.
MAY BE A FEW PERIODS OF BKN MVFR CLOUDS AT ANY TIME THIS AFTERNOON
THRU TONIGHT...BUT WITH WEAK SUBSIDENCE AND FLOW GRADUALLY BECOMING
MORE ANTICYCLONIC...SCT/FEW CLOUDS LOOKS TO PREVAIL.
GRADIENT WILL REMAIN FAIRLY TIGHT THIS AFTERNOON FOR CONTINUED BRISK
NORTHWEST WINDS. GRADIENT GRADUALLY RELAXES TONIGHT/TUE AS THE SFC
RIDGE AXIS SLOWLY DRIFTS EAST FROM THE DAKOTAS TO NEAR THE MS RIVER
BY 00Z WED. WIND CHILLS ACROSS THE AIR FIELDS WILL REMAIN IN THE -20
TO -35 RANGE THRU LATE MORNING TUE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CST MON JAN 21 2013
WI...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
255 PM CST MON JAN 21 2013
.TONIGHT AND TUESDAY - CONFIDENCE...MEDIUM TO HIGH
CORRIDOR OF ARCTIC CHILL CONTINUES THIS PERIOD. TIGHT PRESSURE
GRADIENT CONTINUES TONIGHT INTO AT LEAST EARLY TUESDAY. NOT THE BEST
RADIATIONAL CONDITIONS WITH THE MIXING. DECENT AGREEMENT AMONGST THE
MODELS ON 925 TEMPS OF -24 TO -26C. WILL DROP BELOW ZERO CWA WIDE
YIELDING DANGEROUS WIND CHILLS OF 20 TO 30 BELOW ZERO. RAP SOUNDINGS
SHOW A FAIRLY WELL MIXED LOWEST 2K FEET THROUGH 4 AM OR SO...THEN
SOUNDINGS SHOW LESS MIXING. DANGEROUS CONDITIONS THROUGH THE MORNING
COMMUTE GIVEN THE BITTER AIRMASS/WIND CHILLS. MODELS IN DECENT AGREEMENT
TO BRING READINGS ABOVE ZERO INTO THE LOW/MID SINGLE DIGITS FOR
TUESDAY. GRADIENT SHOWS SOME SLACKENING INTO THE AFTERNOON SO GOING
MIDDAY EXPIRATION SEEMS REASONABLE.
.TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
EXPECT INCREASING CLOUDS LATER TUESDAY NIGHT AS A SHOT OF WARM
ADVECTION APPROACHES. THIS IS AHEAD OF A WEAK TROF/COLD FRONT
DROPPING IN FROM THE NORTHWEST. THE EARLY CLEAR SKIES TUESDAY
EVENING ALONG WITH LIGHT WINDS UNDER A RIDGE OF HIGH PRESSURE WILL
ALLOW TEMPS TO PLUMMET QUICKLY DURING THE EVENING. LOWS WILL RANGE
FROM 4 ABOVE TO 4 BELOW...THOUGH WIND CHILLS WON/T BE MUCH OF A
FACTOR. THE WARM ADVECTION WITH SOME ADDITIONAL MOISTURE COULD
BRING SOME SCATTERED FLURRIES TO THE AREA ON WEDNESDAY. THERE IS
AN OUTSIDE CHANCE A FEW SITES WILL MEASURE...BUT NOT ENOUGH TO
HAVE POPS ABOVE 14 PERCENT ATTM.
.WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
THE WEAK COLD FRONT SHOULD HAVE EXITED SOUTHERN WISCONSIN BY
EVENING. HIGH PRESSURE AND COLD AIR SETTLE IN FOR THE NIGHT. SKIES
WILL ALSO CLEAR. SO...EXPECT LOWS IN THE SINGLE DIGITS THURSDAY
MORNING.
.THURSDAY AND FRIDAY...FORECAST CONFIDENCE IS MEDIUM.
THE MODELS HAVE BEEN STRUGGLING ON TIMING WITH REGARD TO LOW
PRESSURE MOVING THROUGH THE REGION LATE IN THE WEEK...LIKELY
BRINGING A LITTLE ACCUMULATING SNOW. THIS WOULD BE ON THE ORDER OF
1/2 TO POSSIBLY 2 INCHES...THURSDAY NIGHT INTO FRIDAY. NOTHING
MAJOR. THE MID LEVELS FEATURE A DECENT SHORT WAVE PUSHING OUT OF
THE PACIFIC NORTHWEST ON WEDNESDAY...THEN PHASING WITH THE LARGE
TROF OVER EASTERN CANADA ON THURSDAY. AS IT DIVES INTO THE
NORTHERN U.S. A RATHER LARGE LONG WAVE TROF FORMS FROM HUDSON BAY
CANADA TO NORTHERN IOWA BY FRIDAY MORNING. SFC CYCLOGENESIS OCCURS
OVER BOTH THE NORTHERN PLAINS AND THE SOUTHERN MS
VALLEY...EVENTUALLY THEY MERGE INTO ONE SFC LOW THAT MOVES WELL
SOUTH OF WI...TOWARD THE EAST COAST.
THE MODELS HAVE SLOWED ALL THIS DOWN BY A GOOD 6 TO 12 HOURS. HIGH
PRESSURE WILL KEEP IT QUIET FOR MOST OF THURSDAY. THEN THE WARM
AIR ADVECTION ARRIVES THURSDAY AFTERNOON INTO THURSDAY NIGHT...AND
THAT/S GOOD FOR A CHANCE OF SNOW. THEN THE WEAK NORTHERN LOW
SLIDES BY ON FRIDAY...KEEPING THE CHANCE OF SNOW ALIVE. THIS LOW
THEN MERGES WITH THE SOUTHERN LOW...BRINGING A SLOW END TO THE
LIGHT SNOW BY FRIDAY NIGHT.
AGAIN...ANY SNOW AMOUNTS WILL LIKELY BE KEPT AT BETWEEN 1/2 TO
MAYBE 2 INCHES.
.SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
HIGH PRESSURE ARRIVES BY SATURDAY FOR A QUIET STRETCH INTO EARLY
SUNDAY. THEN A WEAK TROF PUSHES IN FROM THE WEST AND THIS COULD
LEAD TO SOME LIGHT SNOW CHANCES LATER ON SUNDAY.
&&
.AVIATION/00Z TAFS/...NW WINDS RAMPED UP WITH TIGHT PRESSURE
GRADIENT BETWEEN PLAINS SURFACE RIDGE AND LOW PRESSURE OVER EASTERN
UPPER MICHIGAN. STILL QUITE A BIT OF MVFR IN THE COLD CYCLONIC
REGIME. WOULD EXPECT KEEPING SOME OF THIS AROUND TONIGHT. LOW LEVEL
RH PROGS SHOWING CONSIDERABLY LESS CU POTENTIAL TUESDAY.
&&
.MARINE...NO CHANGE TO SMALL CRAFT ADVISORY A WINDS EXPECTED TO
REMAIN GUSTY WITH TIGHT PRESSURE GRADIENT. EXPECT WINDS TO EASE BY
MIDDAY TUESDAY AS GRADIENT LOOSENS UP SOME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ046-047-051-
052-056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST TUESDAY FOR LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR
TUESDAY NIGHT THROUGH MONDAY...DAVIS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
232 PM CST MON JAN 21 2013
.SHORT TERM...TONIGHT AND TUESDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE STRETCHING SOUTHEAST ACROSS THE GREAT PLAINS EARLY THIS
AFTERNOON. WEAK SHORTWAVE IS DROPPING ACROSS THE STATE WHICH IS
CONTRIBUTING TO A STRATO-CU FIELD...WITH THE HELP FROM STEEP LOW
LEVEL LAPSE RATES. SCT FLURRIES ARE FALLING OUT OF THIS STRATO-CU
DECK FROM THE SOUTHERN FOX VALLEY TO CENTRAL AND NORTH-CENTRAL
WISCONSIN. TEMPERATURES AND WIND CHILL READINGS HAVE HARDLY BUDGED
SINCE EARLIER THIS MORNING...AND PLENTY OF 30-35 BELOW WIND CHILL
READINGS REMAIN OVER NORTH-CENTRAL WISCONSIN. FORECAST CONCERNS
INCLUDE CLOUD TRENDS AND WIND CHILL HEADLINES.
TONIGHT...ARCTIC HIGH PRESSURE WILL BE BUILDING SOUTHEAST ACROSS THE
NORTHERN MISSISSIPPI VALLEY THROUGH THE NIGHT. SHORTWAVE TROUGH
OVERHEAD WILL BE EXITING THE REGION BY LATE THIS AFTERNOON OR EARLY
THIS EVENING. WITH LOSS OF A SMALL DIURNAL COMPONENT...AM COUNTING
ON INCREASING SUBSIDENCE TO HELP GRADUALLY DISSIPATE MUCH OF THE
STRATO-CU FIELD OVER CENTRAL AND EAST-CENTRAL WISCONSIN THIS
EVENING. NORTH-CENTRAL WISCONSIN MAY NOT CLEAR OUT MUCH AT ALL...AS
LOW LEVEL WINDS VEER AROUND SLIGHTLY TO THE NORTHWEST AND PUSH LAKE
EFFECT CLOUDS SOUTHEAST BENEATH A FAIRLY SHARP INVERSION. TOO COLD
FOR MUCH ACCUMS...BUT POSSIBLY UP TO AN INCH OVER THE FAR NORTHERN
PART OF THE COUNTY. THE CLEARING SKIES WILL HELP TEMPS BECOME
COLDER TONIGHT COMPARED TO LAST NIGHT...BUT THIS WILL BE OFFSET BY A
WEAKENING PRESSURE GRADIENT AND WIND SPEEDS. APPARENT TEMP GRIDS
SHOW WIND CHILLS FALLING ONLY A FEW DEGREES THIS EVENING...BUT
READINGS HAVE REMAINED STEADY ACROSS NORTH-CENTRAL WISCONSIN
TODAY...SO WILL NOT TAKE MUCH OF A FALL TO REACH WARNING CRITERIA.
AFTER COORDINATING WITH SURROUNDING OFFICES...WILL ISSUE A WIND
CHILL WARNING WHERE AM MOST CONFIDENT IN REACHING CRITERIA...FROM
LINCOLN AND LANGLADE TO VILAS AND FOREST COUNTY STARTING THIS
EVENING AND GOING THROUGH MID-MORNING TUESDAY.
TUESDAY...ARCTIC HIGH PRESSURE WILL BE SLIDING TO THE OHIO VALLEY.
CORE OF THE COLDEST AIR WILL BE SHIFTING TO THE NORTHEAST...ALONG
WITH THE HIGHER LOW LEVEL HUMIDITY. BUT WILL ALREADY BE OFF TO A
VERY COLD START SO TEMPS WILL NOT BE SIGNIFICANTLY WARMER THAN
TODAYS READINGS. WITH WINDS BACKING TO THE WEST...SHOULD SEE MORE
SUNSHINE THAN TODAY. WINDS WILL ALSO BE LIGHTER...AND WIND CHILL
READINGS SHOULD BE IMPROVING RAPIDLY BY MID TO LATE MORNING. WILL
CONTINUE TO RUN WIND CHILL HEADLINES TO 18Z. HIGHS RANGING FROM 5
BELOW NORTH TO ABOUT 4 ABOVE NEAR LAKE MICHIGAN.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. PRIMARY ISSUE
CONTINUES TO BE THE DURATION OF THE COLD AIR THIS WEEK FOLLOWED BY
A CLIPPER TYPE SYSTEM LATER THIS WEEK.
COLD AIR INTRUSION CONTINUES TUESDAY NIGHT WITH THE LIKELY CHANCE
OF ADDITIONAL WIND CHILL HEADLINES ACROSS AT LEAST THE NORTH HALF
OF THE FORECAST AREA. A WEAK TROUGH IS PROGGED DROPS OVER THE GREAT
LAKES REGION IN THE NORTHWEST FLOW WED INTO WED EVENING...FOLLOWED
WITH ANOTHER BRIEF PERIOD OF CAA INTO THURSDAY MORNING.
THIS BIT LONGER DURATION OF COLDER AIR INTO WEDNESDAY NIGHT
PRECEDES THE TREND OF SLOWING DOWN THE CLIPPER TYPE SYSTEM FOR
LATER THURSDAY AND INTO FRIDAY MORNING...WHICH IS SUPPORTED BY THE
LAST FEW MODEL RUNS. WOULD NOT BE SURPRISED WITH LATER RUNS
INDICATING THE CLIPPER WILL LINGER MORE INTO FRIDAY AS THIS
CLIPPER SYSTEM PHASES WITH A SOUTHERN STREAM SYSTEM. COULD SEE A
FEW INCHES OF SNOW BY FRIDAY OVER MOST LOCATIONS.
AFTER A BRIEF PERIOD OF CAA IN THE WAKE OF THE CLIPPER...GRADUALLY
MODERATING TEMPERATURES TO NEAR SEASONAL NORMS STILL EXPECTED FOR
THE WEEKEND AND INTO MONDAY.
WAA FOR SUNDAY ALONG WITH A H850 TROUGH TRACKING OVER THE AREA
MAY WILL PROVIDE A CHANCE FOR LIGHT SNOW OR FLURRIES.
LAKE EFFECT POTENTIAL. THE CHANCE FOR LAKE EFFECT SNOWS INCREASE
TOWARD WEDNESDAY NIGHT OVER FAR NORTHERN WISCONSIN AS THE SHORT
WAVE TROUGH SWINGS THROUGH AND WINDS TURN BRIEFLY NORTHWEST AGAIN.
NORTHWEST WINDS WILL NOT LAST LONG AS THE COLD SURFACE HIGH
DROPS INTO THE REGION. BUT WINDS BEGIN TO TURN MORE EASTERLY
THURSDAY INTO THURSDAY NIGHT TO INCREASE THE POTENTIAL OF MORE
SNOW SHOWERS ALONG LAKE MICHIGAN..ESPECIALLY AS THE WEAK CLIPPER
TRACKS THROUGH TO PROVIDE SOME LIFT. COULD HAVE HIGHER SNOW
AMOUNTS ALONG THE LAKE MICHIGAN SHORELINE THURSDAY NIGHT INTO
FRIDAY.
&&
.AVIATION...EXPECT MAINLY VFR CONDITIONS TODAY AND TONIGHT...
ALTHOUGH ISOLD MVFR CONDITIONS ARE POSSIBLE AS AN UPPER TROF AND
SECONDARY SURGE OF ARCTIC AIR PUSHES THROUGH THIS MORNING. LAKE-
EFFECT SNOW SHOWERS WILL ALSO IMPACT VILAS COUNTY AT TIMES...
BRINGING OCNL MVFR/IFR CONDITIONS NEAR THE UPPER PENINSULA BORDER.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ012-013-
020>022-030-031-035>040-045-048>050-073-074.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR WIZ005-010-011-018-
019.
&&
$$
MPC/TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CST MON JAN 21 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
306 AM CST MON JAN 21 2013
THE CONTINUED FOCUS REMAINS ON THE BITTERLY COLD AIR MASS THAT HAS
HUNKERED DOWN ACROSS THE REGION AND WILL LINGER THROUGH THE NEXT
FEW DAYS.
BROAD CYCLONIC FLOW ALOFT REMAINS ENTRENCHED ACROSS THE REGION AS
THE POLAR VORTEX HAS DRIFTED INTO SOUTHEAST CANADA. AS SHORT WAVE
TROUGHS HAVE PROPAGATED ALONG THE WESTERN PERIPHERY OF THIS
TROUGH...THEY HAVE BROUGHT REINFORCING SHOTS OF COLD AIR ON DOWN
WITH THEM. THE LATEST SHORT WAVE CAME THROUGH EARLY THIS MORNING
AS NOTED ON WATER VAPOR IR. AHEAD OF THIS TROUGH...A COLD FRONT
ALSO MOVED INTO THE REGION WHICH BROUGHT SOME FLURRIES AND SNOW
SHOWERS IN AS WELL. BEHIND THIS FRONT...SKIES CLEAR OUT AND
TEMPERATURES DROP BELOW ZERO. A STRENGTHENING PRESSURE GRADIENT
ALSO HELPED TO INCREASE THE SURFACE WINDS AND TO DROP WIND CHILLS
DOWN INTO THE ADVISORY LEVELS. AS THIS COLDER AIR MASS SHIFTS TO
THE SOUTHEAST THIS MORNING THESE LOWER WIND CHILLS WILL ALSO START
TO OCCUR AT SITES IN NORTHEAST IOWA AND WESTERN WISCONSIN THAT
HAVE BEEN IN THE -5 TO -15F RANGE SO FAR.
HAD THERE BEEN ANY SNOW COVER ON THE GROUND...TEMPERATURES
PROBABLY WOULD NOT MAKE IT ABOVE ZERO TODAY. FORTUNATELY...THE
SNOW PACK MELTED AWAY LAST WEEK AND THE LATEST NOHRSC SNOW DEPTH
ANALYSIS AND LOCAL COOP OBSERVERS SHOWS MOSTLY ZERO SNOW COVER
OUTSIDE OF A FEW SPORADIC 1-3 INCH REPORTS. EVEN WITHOUT THE SNOW
COVER...TEMPERATURES ARE GOING TO REMAIN COLD AS THE CORE OF THE
COLD AIR MASS DROPS DOWN ACROSS THE REGION. 850MB TEMPERATURES
WILL STICK AROUND -25C FOR MOST OF THE AREA WITH THE COLDEST
POCKET OF AIR RUNNING FROM NORTHEAST MINNESOTA INTO NORTH CENTRAL
WISCONSIN. WIND CHILLS SHOULD STAY NEAR OR BELOW -20F THROUGH THE
DAY...SO WILL NOT MAKE ANY CHANGES TO THE WIND CHILL ADVISORY.
21.06Z RAP SOUNDINGS SHOW THAT THERE COULD BE SOME CU THAT FORMS
EAST OF THE RIVER TODAY...SO CAN NOT RULE OUT SOME FLURRIES THERE
AS WELL. BASICALLY...IF WE GET ANY LOW LEVEL CLOUD COVER OVER THE
NEXT FEW DAYS...THERE WILL LIKELY BE SOME FLURRIES OR SNOW SHOWERS
THAT ACCOMPANY IT WITH THE LOW LEVEL TEMPERATURE PROFILE BELOW
-20C. AT THESE TEMPERATURES...WOULD MAINLY EXPECT THE SNOWFLAKES
TO BE PLATES AND COLUMNS AND NOT AMASS TO MUCH IF ANYTHING.
TEMPERATURES WILL START TO IMPROVE ON TUESDAY AS THE BROAD UPPER
TROUGH SHIFTS EAST AND THE CORE OF THE SURFACE RIDGE MOVES ACROSS
THE REGION WITH LOW LEVEL WINDS COMING AROUND TO THE SOUTHWEST.
WILL HAVE TO KEEP AN EYE ON TUESDAY NIGHT INTO WEDNESDAY FOR THE
POTENTIAL OF SOME WARM AIR ADVECTION SNOW. THE 21.00Z NAM IS A BIT
STRONGER WITH THE LOW LEVEL LIFT AND SATURATION COMPARED TO THE
REST OF THE GUIDANCE. HAVE KEPT JUST FLURRIES IN THE FORECAST FOR
NOW...BUT MAY NEED TO RAMP THINGS UP IF THE FORCING DOES LOOK
LEGIT.
.LONG TERM...THURSDAY THROUGH SUNDAY
306 AM CST MON JAN 21 2013
GOING INTO THE LATER PORTION OF THE WEEK ON INTO THE WEEKEND...THE
MAIN FOCUS IS ON A SYSTEM THAT WILL DROP OUT OF SOUTH CENTRAL
CANADA THURSDAY INTO FRIDAY AND BRING THE NEXT BEST CHANCE FOR AN
ACCUMULATING SNOW WITH IT. TRENDS HAVE WAVERED BACK AND FORTH ON
THE TIMING OF WHEN THIS FEATURE MOVES IN WITH THE 21.00Z GFS/ECMWF
SLOWING IT DOWN A TAD WITH MUCH OF THE SNOW FALLING THURSDAY
AFTERNOON INTO FRIDAY MORNING. 21.00Z GFS BUFKIT SOUNDINGS FOR
THIS EVENT SHOW A FAIRLY DEEP DENDRITIC GROWTH ZONE WITH FORCING
THROUGH THIS LAYER WHICH COULD LEAD TO SOME HIGH SNOW RATIOS.
DETAILS WILL NEED TO BE WORKED OUT ON THIS SYSTEM...BUT IT LOOKS
LIKE THE POTENTIAL IS THERE FOR AN ACCUMULATING SNOW...WITH THE
BETTER CHANCES FOR ACCUMULATIONS IN CENTRAL WISCONSIN.
TEMPERATURE-WISE...WE ARE STILL IN NORTHWEST FLOW ALOFT...SO THE
COOL AIR WILL REMAIN IN PLACE THOUGH NEXT WEEKEND WITH
TEMPERATURES LINGERING MAINLY JUST BELOW NORMAL.
&&
.AVIATION...THIS AFTERNOON THROUGH TUESDAY
1130 AM CST MON JAN 21 2013
MAIN PROBLEM IS THE APPARENT OVER-REPORTING OF BKN-OVC CIGS BY THE
ASOS/AWOS SYSTEMS AROUND THE AREA LATE THIS MORNING...WHICH SEEMS
MORE COMMON IN VERY COLD AIRMASSES. PERUSAL OF WEB CAMS AND LOOK OUT
THE OFFICE WINDOWS/AROUND THE LOCAL HORIZON SHOWS PLENTY OF SUNSHINE
AND CLOUDS MORE SCT AT BOTH KRST/KLSE LATE THIS MORNING. THUS
CARRIED SCT MVFR CLOUDS THIS AFTERNOON AT BOTH KRST/KLSE. MODELS
HANG ONTO SOME LOWER LEVEL MOISTURE NEAR 925MB TONIGHT INTO TUE
MORNING...AND CONTINUED SCT MVFR CLOUDS THRU TONIGHT/TUE MORNING.
MAY BE A FEW PERIODS OF BKN MVFR CLOUDS AT ANY TIME THIS AFTERNOON
THRU TONIGHT...BUT WITH WEAK SUBSIDENCE AND FLOW GRADUALLY BECOMING
MORE ANTICYCLONIC...SCT/FEW CLOUDS LOOKS TO PREVAIL.
GRADIENT WILL REMAIN FAIRLY TIGHT THIS AFTERNOON FOR CONTINUED BRISK
NORTHWEST WINDS. GRADIENT GRADUALLY RELAXES TONIGHT/TUE AS THE SFC
RIDGE AXIS SLOWLY DRIFTS EAST FROM THE DAKOTAS TO NEAR THE MS RIVER
BY 00Z WED. WIND CHILLS ACROSS THE AIR FIELDS WILL REMAIN IN THE -20
TO -35 RANGE THRU LATE MORNING TUE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CST MON JAN 21 2013
WI...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS