Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/29/13
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
705 PM EST MON JAN 28 2013
.UPDATE (TONIGHT THROUGH TUESDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A SLOWLY AMPLIFYING UPPER
LEVEL PATTERN ACROSS THE CONUS...AS SHARP TROUGHING OVERSPREADS THE
INTER-MOUNTAIN WEST TOWARD THE CENTRAL PLAINS AND BEGINS TO FORCE
MODEST DOWNSTREAM HEIGHT RISES OVER THE EASTERN STATES. THIS
ENHANCED DOWNSTREAM RIDGING WILL HELP TO KEEP OUR LOCAL WEATHER DRY
AND UNSEASONABLY WARM THROUGH TUESDAY. AT THE SAME TIME...THE
ADVANCING TROUGH AND ASSOCIATED SURFACE COLD FRONT ACROSS THE
CENTRAL PORTION OF THE COUNTRY IS EXPECTED TO RESULT IN A
POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT FOR PORTIONS OF THE
LOWER/MIDDLE MS VALLEY DURING TUESDAY/TUESDAY NIGHT. THIS COLD FRONT
WILL EVENTUALLY PROGRESS TO THE EASTERN GULF AND FL PENINSULA LATE
WEDNESDAY AND WEDNESDAY NIGHT WITH A BROKEN BAND OF SHOWERS AND
STORMS. AT THAT TIME...THE BETTER CHANCES FOR ANY LINGERING STRONG
TO SEVERE STORMS SHOULD REMAIN TO OUR NORTH ACROSS SOUTHERN GA AND
THE CAROLINAS. WILL CONTINUE TO MONITOR THE SITUATION FOR A FEW
STRONGER STORMS BY MIDWEEK...HOWEVER AS IS OFTEN THE CASE WITH THESE
SYSTEMS...THE BETTER KINEMATIC AND THERMODYNAMIC FORCING ALOFT LOOKS
TO BE DEPARTING NORTHEASTWARD BY THE TIME THE BEST LOW LEVEL FOCUS
ARRIVES.
THAT IS A COUPLE DAYS AWAY THOUGH. AS MENTIONED ABOVE...BEFORE
THAT...OUR WEATHER WILL REMAIN QUITE PLEASANT WITH VERY LOW RAIN
CHANCES AND WARM DAYTIME TEMPERATURES. THE RIDGING ALOFT WILL BE
COMPLEMENTED BY AN AREA OF SURFACE HIGH PRESSURE OFF THE SOUTHEAST
COAST THAT WILL CONTINUE TO RIDGE BACK WESTWARD OVER THE AREA. THE
RIDGE AXIS SINKS SOUTH TOWARD THE I-10 CORRIDOR OVER THE NEXT 24
HOURS KEEPING OUR LOW LEVEL FLOW FROM THE EAST/SE.
EXPECTING SOME AREAS OF FOG TO DEVELOP DURING THE SECOND HALF OF
TONIGHT. BOUNDARY LAYER FLOW IS SLIGHTLY ENHANCED WHICH MAY HELP TO
TRANSITION TO MORE OF A LOWER CEILING EVENT AS OPPOSED TO GROUND
FOG...BUT WILL LEAVE THE MENTION OF FOG IN THE FORECAST FOR THOSE
AREAS THAT DO SEE A MORE DEFINITIVE BOUNDARY LAYER DE-COUPLING. ANY
EARLY MORNING FOG WILL LIFT WITHIN A COUPLE HOURS OF SUNRISE...AND
LEAD TO A PARTLY SUNNY TUESDAY. TEMPERATURES WILL AGAIN WARM INTO
THE LOWER 80S FOR MANY LOCATIONS AWAY FROM THE IMMEDIATE COAST.
SIMILAR TO WHAT OCCURRED TODAY...THE STRONG INLAND HEATING LOOKS TO
SUPPORTS A FEEBLE SEA BREEZE...THAT WOULD KEEP THE BEACHES A FEW
DEGREES COOLER DURING THE MID/LATE AFTERNOON. MANY OF THE HIRES
GUIDANCE MEMBERS AS POINTING TOWARD THIS SEA-BREEZE POTENTIAL AND
HAVE UPDATED THE NEAR COAST WIND AND TEMPERATURE GRIDS TO
REFLECT THIS DEVELOPING AFTERNOON ONSHORE COMPONENT.
&&
.AVIATION...
VFR EXPECTED THROUGH 07Z-09Z THEN INCREASING RISK OF IFR WITH LOW
CLOUDS AND PERHAPS SOME FOG. BEST CHANCES WILL BE TPA...PIE AND LAL
WITH LOWER CHANCES FMY AND RSW. VFR WITH GUSTY SOUTHERLY WINDS ON
TUESDAY.
&&
.MARINE...
HIGH PRESSURE OFFSHORE THE MID ATLANTIC COAST WILL SINK SOUTH ACROSS
THE NORTH CENTRAL PENINSULA AND ADJACENT GULF WATERS THROUGH TUESDAY
NIGHT. THE HIGH WILL MOVE SOUTHEAST ON WEDNESDAY AS A COLD FRONT
MOVES THROUGH THE FLORIDA PANHANDLE DURING THE DAY.
A TIGHTENING PRESSURE GRADIENT AHEAD OF THE FRONT WILL SUPPORT WINDS
AND SEAS INCREASING TO THE EXERCISE CAUTION RANGE...BEFORE FURTHER
INCREASING TO THE ADVISORY RANGE DURING WEDNESDAY. WINDS SHIFT TO
THE NORTHWEST AND NORTH IN THE WAKE OF THIS FRONT WEDNESDAY NIGHT
AND CONTINUE AT ADVISORY LEVELS INTO THURSDAY. SURFACE HIGH PRESSURE
WILL THEN BUILD IN OVER THE NORTHERN GULF IN THE WAKE OF THE FRONT
THURSDAY NIGHT THROUGH SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 64 81 65 80 / 10 10 10 10
FMY 64 84 63 84 / 10 10 10 10
GIF 61 82 61 84 / 10 10 10 10
SRQ 63 80 64 80 / 10 10 10 10
BKV 60 82 61 82 / 10 10 10 20
SPG 65 80 65 79 / 10 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
511 AM CST SUN JAN 27 2013
.DISCUSSION...
SHORT TERM (THROUGH MONDAY)...
500 AM CST
FREEZING RAIN ADVISORIES HAVE BEEN POSTED FOR ALL OF THE FORECAST
AREA.
SHORT TERM FOCUS IS ON THE EXPECTED PERIOD OF MAINLY FREEZING
RAIN...POSSIBLY MIXED WITH A BRIEF PERIOD OF SLEET AT THE ONSET
OF THE PRECIPITATION. DELICATE BALANCE BETWEEN TEMPERATURES ALOFT
AND AT THE SURFACE TODAY AS WELL AS HOW DRY THE LOWER LEVELS
MAINTAIN LARGE DEW POINT DEPRESSIONS INTO THIS MORNING MAKE FOR A
CHALLENGING FORECAST.
00Z RAOBS SHOWED THE 850 HPA TEMPERATURES ALREADY AT OR ABOVE 0C
FROM MSP TO SPI TO SDF WITH +5C FROM ABR TO OMA TO SGF. VAD WINDS
SHOWING THAT THE STRONG LOWER LEVEL SOUTH TO SOUTHWEST FLOW HAS
SPREAD EASTWARD FROM THE SOUTHERN AND CENTRAL PLAINS TO AS FAR
EAST AS WEST CENTRAL AND SOUTHWEST WI...EASTERN IA...AND WEST
CENTRAL AND SOUTHWEST IL EARLY THIS MORNING. LOW LEVEL AND
SURFACE FLOW REMAINS OUT OF THE SOUTHEAST ACROSS THE REGION WHICH
CONTINUES TO FEED DRY AIR ACROSS THE FORECAST AREA.
UPSTREAM TO THE SOUTHWEST THROUGH WEST SURFACE DEW POINTS HAVE
CLIMBED INTO THE MID 30S TO LOWER 40S F AS FAR NORTH AND EAST AS
THE MID MO VALLEY...THE OZARKS AND THE LOWER MS VALLEY. THIS LOW
LEVEL MOISTURE WAS EVIDENT IN THE 00Z RAOBS WITH 925 HPA DEW
POINT DEPRESSIONS OF ZERO TO TWO DEGREES C FROM OK SOUTH ACROSS
EAST TX AND EAST TO LA. THIS MOISTURE IS PROGGED TO REACH WESTERN
AND SOUTHERN IA...FAR EASTERN MO AND FAR WESTERN TN BY 12Z AND
THEN SPREADS ACROSS IL FROM LATE MORNING THROUGH LATE AFTERNOON.
STRONG WARM AIR ADVECTION WAS PRODUCING ISENTROPIC UPGLIDE ACROSS
THE REGION BUT THE DRY LOW LEVELS WAS PREVENTING AN PRECIPITATION
FROM OCCURRING ANY CLOSER THAN 250 TO 300 MI TO THE SOUTHWEST
THROUGH WEST AS OF 10Z. HOWEVER A LARGE AREA OF RAIN WAS QUICKLY
SPREADING INTO SO SOUTH CENTRAL IA AND NORTHEAST AND EAST CENTRAL
MO AS THE MOISTURE SURGES NORTH AND NORTHEAST ALLOWING THE LOWER
LEVELS TO SATURATE. SIGNIFICANT ISENTROPIC UPGLIDE THROUGH THE
LOWER AND MID LEVELS AND THE CONTINUED MOISTURE ADVECTION
SPREADING INTO THE LOCAL AREA IS EXPECTED TO SATURATE DOWN FROM
THE MID LEVELS TO THE LOWER LEVELS ACROSS THE WESTERN COUNTIES BY
MID MORNING AND THE EASTERN COUNTIES BY MIDDAY.
TEMPERATURES WERE STEADY OR ROSE A DEGREE OR TWO FROM LATE LAST
EVENING AND WERE MAINLY IN THE MID 20S MOST OF THE LATE NIGHT.
WITH TEMPERATURES STARTING OFF NOT THAT FAR FROM FREEZING THEY
ARE FORECAST TO REACH 32 OR SLIGHTLY ABOVE ACROSS THE SOUTHERN
PORTION OF THE FORECAST AREA BY EARLY AFTERNOON AND THE NORTHERN
PORTION BY MID TO LATE AFTERNOON. EXPECTED ONSET OF PRECIPITATION
AND TIMING OF SURFACE TEMPERATURES RISING TO FREEZING OR ABOVE
WERE USED TO DETERMINE THE HOURS COVERED BY THE FREEZING RAIN
ADVISORIES ACROSS THE AREA.
THE STRONG SHORT WAVE OVER THE CENTRAL PLAINS EARLY THIS MORNING
WILL CONTINUE FAIRLY QUICKLY NORTHEASTWARD TO THE UPPER MIDWEST
BY LATE AFTERNOON AND THEN IS PROGGED TO SLOW ITS THIS EVENING
AND ON PROGRESS TO FAR NORTHERN WI...THE WESTERN U.P. OF MI AND
WESTERN LAKE SUPERIOR OVERNIGHT. THIS ALLOWS A CONTINUED STRONG
SOUTHWEST TO WEST-SOUTHWEST LOW AND MID LEVEL FLOW TO PERSIST
TONIGHT MAINTAINING THE WARM AIR ADVECTION AND THE RESULTING UVV
SO RAIN WILL MOST LIKELY PERSIST WELL INTO THE NIGHT.
WITH DEW POINTS IN THE MID 30S TO MID 40S ACROSS THE AREA FOG IS
EXPECTED TO DEVELOP DURING THE NIGHT AND PERSIST INTO MONDAY
MORNING. A CHANCE OF RAIN WILL PERSIST AS THE WARM AIR ADVECTION
CONTINUES. WITH 850 HPA TEMPERATURES OF 7 TO 9C OVER THE AREA
DURING MONDAY. CLOUD COVER WILL LIMIT SURFACE HEATING BUT
TEMPERATES SHOULD STILL RESPOND TO THIS MID AIR MASS BY CLIMBING
TO THE MID 40S NORTH AND LOWER 50S SOUTH.
LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...
311 AM CST
MOTHER NATURE LOOKS TO HAVE SOMETHING FOR ALMOST EVERYONE DURING
THIS PERIOD WITH THE POTENTIAL FOR THUNDERSTORMS (SEVERE?)...HEAVY
RAIN/FLOODING...RECORD WARMTH...GUSTY WINDS...AND COLD WITH BIG
ACCUMULATING SNOW ABOUT THE ONLY THING MISSING!
SERIES OF WEAK IMPULSES WILL RIPPLE THROUGH THE BRISK SOUTHWESTERLY
FLOW ALOFT AS DEEP TROUGH PROGRESSES EASTWARD INTO THE PLAINS. ONE
SUCH WAVE AND ITS ASSOCIATED SURFACE LOW PROGGED TO AFFECT THE
REGION MONDAY NIGHT WITH WARM FRONT PROGGED TO LIFT NORTH ACROSS THE
AREA SENDING UNSEASONABLY WARM AND HUMID AIR FLOODING NORTHWARD INTO
THE AREA. STRONG WAA/ASCENT ON THE NOSE OF THE 50KT+ LOW LEVEL JET
SHOULD TRANSPORT MOISTURE/ELEVATED INSTABILITY NORTHWARD WHICH LOOKS
TO BE ENOUGH TO SUPPORT ELEVATED CONVECTION MONDAY NIGHT AND HAVE
INTRODUCED THUNDERSTORMS INTO THE GRIDS MONDAY NIGHT.
TUESDAY LOOKS TO BE A BREEZY AND UNSEASONABLY WARM AND HUMID DAY
WITH RECORD HIGHS IN JEOPARDY. WRF-NAM IS A BIT FASTER WITH THE
TROUGH AND FARTHER EAST WITH THE FRONT BUT IS AN OUTLIER WITH THE
GFS/UKMET/ECMWF/GEM ALL SLOWER AND SUPPORTING RECORD WARMTH OVER THE
ENTIRE CWA. HAVE BUMPED UP HIGHS TUESDAY TO BE IN LINE WITH THE MAV
GUIDANCE...AND CONSIDERING THE TYPICAL INABILITY OF MOS TO CAPTURE
RECORD WARMTH EVEN THESE FORECAST NUMBERS COULD BE A HAIR
CONSERVATIVE. ACCOMPANYING THE WARM TEMPERATURES LOOKS TO BE APRIL
LEVEL HUMIDITY WITH DEW POINTS PROGGED TO CLIMB INTO THE 55-60F RANGE
WHICH IF IT PANS OUT WOULD ALLOW FOR AT LEAST WEAK SURFACE BASED
INSTABILITY TO DEVELOP AHEAD OF A STRONG COLD FRONT THAT MOVES
THROUGH LATE TUES INTO TUES NIGHT.
WILL LIKELY SEE LEFT OFF SHOWERS/STORMS MOVE OUT EARLY TUES MORNING
WITH MANY DRY HOURS EXPECTED BEFORE THE NEXT UPSTREAM WAVE LEADS TO
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS DEVELOPING/MOVING INTO THE
AREA LATER TUESDAY. UPPER FLOW IS PROGGED TO BECOME FAIRLY WELL
ALIGNED WITH THE SURFACE FRONT FAVORING SLOW EASTWARD PROGRESS OF
THE BLOSSOMING AREA OF RAIN/THUNDERSTORMS WITHIN THE WARM CONVEYOR
BELT. NOT SURPRISINGLY GIVEN DEW POINTS NEARING 60F...PWATS ARE
PROGGED TO CLIMB TO NEAR RECORD LEVELS FOR JANUARY WHICH REALLY
RAISES CONCERNS ABOUT HEAVY RAINFALL AND FLOODING. UKMET/GEM/ECMWF
ALL SUGGEST THAT OUR SE CWA WILL BE UNDER THE GUN FOR THIS HEAVY
RAINFALL WHILE THE GFS IS MORE OF AN EAST OUTLIER FOCUSING THE HEAVY
RAIN EAST OF OUR CWA. GOING TO SIDE CLOSER TO THE MODEL CONSENSUS
AND BUMP UP POPS TO CATEGORICAL SE CWA AND INCLUDE MENTION OF HEAVY
RAINFALL IN THE GRIDS/ZFP. FOR FURTHER DETAILS SEE HYDROLOGY SECTION
BELOW.
WHILE IT WOULD BE VERY RARE...CANNOT COMPLETELY RULE OUT A SEVERE
THREAT IN THE AREA TUESDAY AS THE UNSEASONABLY HIGH DEW POINTS COULD
RESULT IN WEAK (BUT SUFFICIENT) INSTABILITY TO SUPPORT SEVERE
THUNDERSTORMS IN AN ENVIRONMENT OF VERY STRONG SHEAR AND INCREASING
LARGE SCALE ASCENT. THE NEW SWODY3 OUTLOOK JUST CAME OUT AND HAS
INCLUDED A SLIGHT RISK INTO OUR CWA TUESDAY AND AS BEST I CAN RECALL
THIS MAY BE THE FIRST EVER DAY 3 SLIGHT RISK IN OUR CWA IN JANUARY.
AS UPPER TROUGH AND ASSOCIATED SURFACE FRONT CONTINUE EASTWARD LOOK
FOR BAND OF RAIN/THUNDERSTORMS TO GRADUALLY MOVE EAST OF THE AREA
TUESDAY NIGHT WITH NORTHWEST WINDS USHERING IN MUCH COLDER
CONDITIONS. WEDNESDAY GENERALLY LOOKS TO BE DRY BUT WITH UPPER
TROUGH MOVING THROUGH THE REGION HAVE OPTED TO HANG ONTO SLIGHT
CHANCE OF LIGHT SNOW/FLURRIES...BUT MORE LIKELY THAN NOT MAJORITY OF
THE DAY WILL BE DRY.
HAVE MAINTAINED DRY FORECAST THURS/FRIDAY BUT CERTAINLY CAN`T RULE
OUT A NORTHWEST FLOW "SURPRISE" BRINGING SOME LIGHT SNOW TO THE
REGION AT SOME POINT IN TIME. BEST CHANCE MIGHT BE LATER THURSDAY
INTO THURSDAY NIGHT AS RE-ENFORCING SHOT OF ARCTIC AIR IS PROGGED TO
ARRIVE. COULD ALSO BE SOME LIGHT SNOW HEADING INTO NEXT WEEKEND AS
MILDER AIR MOVES IN AND ARCTIC AIR MASS TEMPORARILY RETREATS.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.HYDROLOGY...
311 AM CST
USGS ANALYSIS OF STREAMFLOW ACROSS THE CWA INDICATES THAT STREAMFLOW
IS CERTAINLY BELOW AVERAGE OVER THE CWA...THOUGH LESS SO OVER THE
IROQUOIS...KANKAKEE...AND VERMILLION RIVER BASINS THAN SOME OF THE
BASINS FARTHER NORTH. THOSE SAME RIVER BASINS APPEAR TO BE AT RISK
FOR THE HEAVIEST RAINFALL EARLY THIS WEEK WITH WIDESPREAD TOTALS OF
1-2 INCHES LOOKING LIKE A GOOD BET AND TOTALS IN EXCESS OF 2 INCHES
POSSIBLE. THIS HEAVY RAIN WOULD BE FALLING ON FROZEN GROUND AND
LIKELY RESULT IN MUCH LOWER THAN AVERAGE INFILTRATION RATES AND
GREATER RUNOFF INCREASING THE THREAT OF FLOODING. RIVER ICE SPOTTER
REPORTS FROM 1/24 INDICATE THAT THERE IS A GREAT DEAL OF ICE
COVERAGE ON THE IROQUOIS AND KANKAKEE RIVERS...AND THIS IS LIKELY
THE CASE ON OTHER STREAMS/RIVERS AS WELL. THE COMBINATION OF RECORD
WARMTH AND RAPIDLY INCREASING STREAMFLOW COULD RESULT IN A
HEIGHTENED RISK OF ICE JAM FLASH FLOODING AS ICE BECOMES DISLODGED
AND SIGNIFICANT ICE FLOW BEGINS.
WHILE THE MOST SIGNIFICANT THREAT OF HEAVY RAINFALL AND FLOODING
APPEARS TO BE OVER THE SOUTHEAST 1/3RD OR SO OF THE CWA...AT LEAST
MODERATE RAINFALL AND RECORD WARMTH COULD RESULT IN AN INCREASED
RISK OF ICE JAM FLOODING OVER NORTH CENTRAL ILLINOIS AS WELL.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* FREEZING RAIN DEVELOPS TOWARD MIDDAY...POSSIBLY STARTING AS A
PERIOD OF SLEET
* CIGS/VSBY FALLING TO MVFR SUNDAY AFTERNOON AND EVENTUALLY IFR
SUNDAY EVENING
* FREEZING RAIN CHANGES TO RAIN LATE THIS AFTERNOON OR EARLY THIS
EVENING AS TEMPS RISE ABOVE FREEZING
* IFR/LIFR CONDITIONS LIKELY FROM MID/LATE EVENING THROUGH
OVERNIGHT TONIGHT
IZZI
//DISCUSSION...UPDATED 09Z...
HAVE NUDGED THE TIMING OF THE ARRIVAL OF THE PRECIP UP JUST A BIT
BASED ON RADAR TRENDS OF LARGE SHIELD OF PRECIPITATION OVER MO
MARCHING RATHER STEADILY NORTHEASTWARD. TEMPERATURES HAVE BEEN
RISING QUITE QUICKLY AHEAD OF THE PRECIPITATION WITH PRECIP ALMOST
ENTIRELY RAIN AT THIS TIME. DRIER AIR IN ADVANCE OF THE RAIN OVER
NORTHERN ILLINOIS COULD SLOW ITS PROGRESSION A BIT BY EATING AWAY
SOME OF THE LEADING EDGE AND EVAPORATIVE COOLING COULD BE ENOUGH
TO COOL TEMPS SLIGHTLY. GIVEN UPSTREAM TRENDS CONFIDENCE IN
FREEZING TODAY HAS WANED SOME AND THE TREND OF TEMPS RISING
QUICKLY AHEAD OF THE PRECIP CONTINUES THE THREAT OF FZRA/PL MAY BE
LOWER OR THE TIME WINDOW OF OCCURANCE SHORTER. PARTICULARLY
CONCERNING SEEING THE LATEST RAP MODEL SHOWING TEMPS NEARING 40F
AHEAD OF THE PRECIP OVER THE CHICAGO AREA...IF THIS VERIFIES THERE
MAY NOT BE MUCH FROZEN/FREEZING PRECIP. NOT PLANNING ANY BIG
OVERHAULS TO THE TAF FORECAST NOW BASED ON THAT ONE MODELS BUT
WILL CONTINUE TO CLOSELY MONITOR TRENDS. HAVE SHORTENED THE
FORECAST DURATION OF THE FZRZ IN THE TAFS WITH THIS UPDATE CYCLE.
IZZI
UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE AND WARM FRONT LIFTING NORTH ACROSS THE
REGION WILL RESULT IN A PERIOD MIXED PRECIPIATION SUNDAY AFTERNOON
BEFORE CHANGING TO ALL RAIN SUNDAY EVENING. FORECAST SOUNDINGS
SUGGEST THAT SATURATION WILL TAKE PLACE FROM TOP-DOWN WHICH
SUGGESTS THAT PRECIP COULD BRIEFLY START AS A PERIOF OF SLEET
BEFORE STRONG WARM AIR ADVECTION RESULTS IN A CHANGE OVER TO
FREEZING RAIN. CONFIDENCE IS LOW ON HOW QUICKLY SFC TEMPS WILL
RISE ABOVE FREEZING BUT DOES APPEAR AS THOUGH AT LEAST A COUPLE
HOURS...POSSIBLY LONGER...OF FZRA IS LIKELY LATER SUNDAY AFTERNOON
INTO EARLY SUNDAY EVENING. STEADY RAIN EXPECTED TO END SUNDAY
EVENING BUT DRIZZLE AND PERIODIC LIGHT RAIN COULD LINGER THROUGH
THE NIGHT SUNDAY.
INITIALLY VFR CIGS SHOULD BUILD DOWN TO MVFR AND EVENTUALLY IFR
SUNDAY AFTERNOON/EVENING...WITH CORRESPONDING REDUCTION IN VSBY
EXPECTED...ESPECIALLY SUNDAY EVENING AS CIGS LOWER AND SOME LIGHT
FOG/DRIZZLE DEVELOPS.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN START TIME OF PRECIP
* LOW-MEDIUM CONFIDENCE IN PRECIP TYPE TODAY
* HIGH CONFIDENCE IN ANY FREEZING PRECIP CHANGING TO ALL RAIN...BUT
LOW CONFIDENCE IN TIMING OF CHANGE OVER
* HIGH CONFIDENCE IN THE GENERAL CIG/VSBY TRENDS...BUT LOW
CONFIDENCE IN PRECISE TIMING
* HIGH CONFIDENCE IN WINDS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...IFR CIGS/VIS LIKELY WITH -RA/BR.
TUESDAY...SHRA/TSRA LIKELY. MVFR LIKELY/IFR POSSIBLE.
WEDNESDAY THROUGH FRIDAY...MVFR CIGS PROBABLE. A FEW PERIODIC
FLURRIES OR LIGHT SNOW SHOWERS POSSIBLE.
KREIN
&&
.MARINE...
216 AM CST
AN ACTIVE PERIOD LIES AHEAD ACROSS THE LAKE BUT AT THIS POINT PEAK
WIND SPEEDS LOOK TO PRIMARILY REMAIN BELOW GALE FORCE THOUGH THERE
MAY BE A FEW PERIODS THAT COME CLOSE. HIGH PRESSURE SPREAD FROM
WESTERN QUEBEC INTO THE OHIO VALLEY. LOW PRESSURE IS DEVELOPING OVER
THE SOUTHERN HIGH PLAINS AND WILL TRACK NORTHEASTWARD AND CROSS
NORTHERN LAKE MICHIGAN MONDAY AFTERNOON. SOUTH WINDS WILL INCREASE
TODAY AS THE INFLUENCE OF HIGH PRESSURE DEPARTS AND PRESSURE START
TO FALL AHEAD OF THE LOW. EXPECT SPEEDS OF AROUND 30 KT LATER THIS
AFTERNOON INTO THE EVENING ESPECIALLY OVER THE SOUTHERN PART OF THE
LAKE BEFORE MUCH WARMER AIR TAKES OVER ALOFT SETTING UP AN
INVERSION. THIS INVERSION LOOKS TO ALLOW WINDS TO EASE OVERNIGHT AND
MONDAY MORNING KEEPING THE STRONGER 40 KT SPEEDS FROM REACHING THE
LAKE SURFACE. WILL CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS
FOR THE NEARSHORE BUT MAY BE ABLE TO MOVE THE END TIME EARLIER FOR
THE INDIANA WATERS BUT WILL HOLD OFF FOR NOW AND LET LATER SHIFTS
SEE HOW THINGS MATERIALIZE. THE SURFACE LOW WILL CROSS THE
NORTHERN PART OF THE LAKE MONDAY AFTERNOON ALLOWING LIGHT WINDS
FOR A TIME NORTH AS THE DIRECTION SHIFTS SOUTHWESTERLY ACROSS THE
SOUTH. WEAK RIDGING THEN QUICKLY CROSSES THE LAKE MONDAY EVENING
KEEPING LIGHT WINDS IN PLACE BUT ANOTHER SURFACE LOW WILL BE
MOVING NORTHEASTWARD FROM THE SOUTHERN PLAINS RESULTING IN A QUICK
SHIFT TO INCREASING SOUTHWESTERLY WINDS. AN INVERSION WILL REMAIN
IN PLACE WITH MUCH WARMER AIR OVER THE LAKE SO THE 40+ KT SPEEDS
AT AROUND 1000 FT ABOVE THE SURFACE WILL REMAIN THERE WHILE LAKE
LEVEL WINDS ARE HELD TO LESS THAN 30 KT CENTRAL AND SOUTH...WITH
LIGHTER WINDS FAR NORTH IN THE WEAK PRESSURE GRADIENT IN THE
TROUGH OF THE APPROACHING LOW. THERE IS SOME INDICATION OF THE LOW
SHIFTING FURTHER NORTH WHICH WOULD THEN LEAD TO MORE OF THE LAKE
SEEING THESE STRONGER WINDS. A SECOND LOW FORMS SOUTHEAST OF THE
LAKE LATER TUESDAY AS A COLD FRONT CROSSES THE LAKE SHIFTING WINDS
TO THE NORTHWEST. MUCH COLDER AIR WILL SPILL IN BEHIND THE FRONT
BRINGING UNSTABLE AIR BACK OVER THE LAKE. AT THIS POINT WIND
SPEEDS DO NOT LOOK TO INCREASE MARKEDLY DESPITE THE COLD ADVECTION
BUT THERE IS STILL SOME UNCERTAINTY IN HOW THE TWO LOWS EVOLVE SO
THERE IS SOME POTENTIAL FOR INCREASED WINDS OVER WHAT IS CURRENTLY
FORECAST TUESDAY NIGHT AND WEDNESDAY.
SEVERAL WEAKER TROUGHS WILL CROSS THE REGION FROM WEDNESDAY THROUGH
EARLY NEXT WEEKEND. WINDS WILL GENERALLY REMAIN WESTERLY WITH
FLUCTUATIONS FROM SOUTHWEST TO NORTHWEST AS EACH TROUGH PASSES WITH
PERIODIC INCREASES IN SPEEDS. WILL NEED TO MONITOR THE STRENGTH OF
THESE AS IT WOULD NOT TAKE MUCH FOR THEM TO PRODUCE AT LEAST SHORT
PERIODS OF GALES BUT FOR NOW WILL KEEP PEAK SPEEDS AROUND 30 KT.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019-ILZ021-
ILZ032-ILZ039...9 AM SUNDAY TO 4 PM SUNDAY.
FREEZING RAIN ADVISORY...ILZ012-ILZ013-ILZ014-ILZ020-ILZ022-
ILZ023-ILZ033...11 AM SUNDAY TO 4 PM SUNDAY.
FREEZING RAIN ADVISORY...ILZ005-ILZ006...11 AM SUNDAY TO 7 PM
SUNDAY.
FREEZING RAIN ADVISORY...ILZ003-ILZ004...9 AM SUNDAY TO 7 PM
SUNDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...11
AM SUNDAY TO 4 PM SUNDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...NOON SUNDAY TO 4
AM MONDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SUNDAY TO 10
AM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
352 AM CST SUN JAN 27 2013
.DISCUSSION...
SHORT TERM (THROUGH MONDAY)...
FORTHCOMING...
LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...
311 AM CDT
MOTHER NATURE LOOKS TO HAVE SOMETHING FOR ALMOST EVERYONE DURING
THIS PERIOD WITH THE POTENTIAL FOR THUNDERSTORMS (SEVERE?)...HEAVY
RAIN/FLOODING...RECORD WARMTH...GUSTY WINDS...AND COLD WITH BIG
ACCUMULATING SNOW ABOUT THE ONLY THING MISSING!
SERIES OF WEAK IMPULSES WILL RIPPLE THROUGH THE BRISK SOUTHWESTERLY
FLOW ALOFT AS DEEP TROUGH PROGRESSES EASTWARD INTO THE PLAINS. ONE
SUCH WAVE AND ITS ASSOCIATED SURFACE LOW PROGGED TO AFFECT THE
REGION MONDAY NIGHT WITH WARM FRONT PROGGED TO LIFT NORTH ACROSS THE
AREA SENDING UNSEASONABLY WARM AND HUMID AIR FLOODING NORTHWARD INTO
THE AREA. STRONG WAA/ASCENT ON THE NOSE OF THE 50KT+ LOW LEVEL JET
SHOULD TRANSPORT MOISTURE/ELEVATED INSTABILITY NORTHWARD WHICH LOOKS
TO BE ENOUGH TO SUPPORT ELEVATED CONVECTION MONDAY NIGHT AND HAVE
INTRODUCED THUNDERSTORMS INTO THE GRIDS MONDAY NIGHT.
TUESDAY LOOKS TO BE A BREEZY AND UNSEASONABLY WARM AND HUMID DAY
WITH RECORD HIGHS IN JEOPARDY. WRF-NAM IS A BIT FASTER WITH THE
TROUGH AND FARTHER EAST WITH THE FRONT BUT IS AN OUTLIER WITH THE
GFS/UKMET/ECMWF/GEM ALL SLOWER AND SUPPORTING RECORD WARMTH OVER THE
ENTIRE CWA. HAVE BUMPED UP HIGHS TUESDAY TO BE IN LINE WITH THE MAV
GUIDANCE...AND CONSIDERING THE TYPICAL INABILITY OF MOS TO CAPTURE
RECORD WARMTH EVEN THESE FORECAST NUMBERS COULD BE A HAIR
CONSERVATIVE. ACCOMPANYING THE WARM TEMPERATURES LOOKS TO BE APRIL
LEVEL HUMIDITY WITH DEWPOINTS PROGGED TO CLIMB INTO THE 55-60F RANGE
WHICH IF IT PANS OUT WOULD ALLOW FOR AT LEAST WEAK SURFACE BASED
INSTABILITY TO DEVELOP AHEAD OF A STRONG COLD FRONT THAT MOVES
THROUGH LATE TUES INTO TUES NIGHT.
WILL LIKELY SEE LEFT OFF SHOWERS/STORMS MOVE OUT EARLY TUES MORNING
WITH MANY DRY HOURS EXPECTED BEFORE THE NEXT UPSTREAM WAVE LEADS TO
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS DEVELOPING/MOVING INTO THE
AREA LATER TUESDAY. UPPER FLOW IS PROGGED TO BECOME FAIRLY WELL
ALIGNED WITH THE SURFACE FRONT FAVORING SLOW EASTWARD PROGRESS OF
THE BLOSSOMING AREA OF RAIN/THUNDERSTORMS WITHIN THE WARM CONVEYOR
BELT. NOT SURPRISINGLY GIVEN DEWPOINTS NEARING 60F...PWATS ARE
PROGGED TO CLIMB TO NEAR RECORD LEVELS FOR JANUARY WHICH REALLY
RAISES CONCERNS ABOUT HEAVY RAINFALL AND FLOODING. UKMET/GEM/ECMWF
ALL SUGGEST THAT OUR SE CWA WILL BE UNDER THE GUN FOR THIS HEAVY
RAINFALL WHILE THE GFS IS MORE OF AN EAST OUTLIER FOCUSING THE HEAVY
RAIN EAST OF OUR CWA. GOING TO SIDE CLOSER TO THE MODEL CONSENSUS
AND BUMP UP POPS TO CATEGORICAL SE CWA AND INCLUDE MENTION OF HEAVY
RAINFALL IN THE GRIDS/ZFP. FOR FURTHER DETAILS SEE HYDROLOGY SECTION
BELOW.
WHILE IT WOULD BE VERY RARE...CANNOT COMPLETELY RULE OUT A SEVERE
THREAT IN THE AREA TUESDAY AS THE UNSEASONABLY HIGH DEWPOINTS COULD
RESULT IN WEAK (BUT SUFFICIENT) INSTABILITY TO SUPPORT SEVERE
THUNDERSTORMS IN AN ENVIRONMENT OF VERY STRONG SHEAR AND INCREASING
LARGE SCALE ASCENT. THE NEW SWODY3 OUTLOOK JUST CAME OUT AND HAS
INCLUDED A SLIGHT RISK INTO OUR CWA TUESDAY AND AS BEST I CAN RECALL
THIS MAY BE THE FIRST EVER DAY 3 SLIGHT RISK IN OUR CWA IN JANUARY.
AS UPPER TROUGH AND ASSOCIATED SURFACE FRONT CONTINUE EASTWARD LOOK
FOR BAND OF RAIN/THUNDERSTORMS TO GRADUALLY MOVE EAST OF THE AREA
TUESDAY NIGHT WITH NORTHWEST WINDS USHERING IN MUCH COLDER
CONDITIONS. WEDNESDAY GENERALLY LOOKS TO BE DRY BUT WITH UPPER
TROUGH MOVING THROUGH THE REGION HAVE OPTED TO HANG ONTO SLIGHT
CHANCE OF LIGHT SNOW/FLURRIES...BUT MORE LIKELY THAN NOT MAJORITY OF
THE DAY WILL BE DRY.
HAVE MAINTAINED DRY FORECAST THURS/FRIDAY BUT CERTAINLY CAN`T RULE
OUT A NORTHWEST FLOW "SURPRISE" BRINGING SOME LIGHT SNOW TO THE
REGION AT SOME POINT IN TIME. BEST CHANCE MIGHT BE LATER THURSDAY
INTO THURSDAY NIGHT AS RE-ENFORCING SHOT OF ARCTIC AIR IS PROGGED TO
ARRIVE. COULD ALSO BE SOME LIGHT SNOW HEADING INTO NEXT WEEKEND AS
MILDER AIR MOVES IN AND ARCTIC AIRMASS TEMPORARILY RETREATS.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.HYDROLOGY...
311 AM CST
USGS ANALYSIS OF STREAMFLOW ACROSS THE CWA INDICATES THAT STREAMFLOW
IS CERTAINLY BELOW AVERAGE OVER THE CWA...THOUGH LESS SO OVER THE
IROQUOIS...KANKAKEE...AND VERMILLION RIVER BASINS THAN SOME OF THE
BASINS FARTHER NORTH. THOSE SAME RIVER BASINS APPEAR TO BE AT RISK
FOR THE HEAVIEST RAINFALL EARLY THIS WEEK WITH WIDESPREAD TOTALS OF
1-2 INCHES LOOKING LIKE A GOOD BET AND TOTALS IN EXCESS OF 2 INCHES
POSSIBLE. THIS HEAVY RAIN WOULD BE FALLING ON FROZEN GROUND AND
LIKELY RESULT IN MUCH LOWER THAN AVERAGE INFILTRATION RATES AND
GREATER RUNOFF INCREASING THE THREAT OF FLOODING. RIVER ICE SPOTTER
REPORTS FROM 1/24 INDICATE THAT THERE IS A GREAT DEAL OF ICE
COVERAGE ON THE IROQUOIS AND KANKAKEE RIVERS...AND THIS IS LIKELY
THE CASE ON OTHER STREAMS/RIVERS AS WELL. THE COMBINATION OF RECORD
WARMTH AND RAPIDLY INCREASING STREAMFLOW COULD RESULT IN A
HEIGHTENED RISK OF ICE JAM FLASH FLOODING AS ICE BECOMES DISLODGED
AND SIGNIFICANT ICE FLOW BEGINS.
WHILE THE MOST SIGNIFICANT THREAT OF HEAVY RAINFALL AND FLOODING
APPEARS TO BE OVER THE SOUTHEAST 1/3RD OR SO OF THE CWA...AT LEAST
MODERATE RAINFALL AND RECORD WARMTH COULD RESULT IN AN INCREASED
RISK OF ICE JAM FLOODING OVER NORTH CENTRAL ILLINOIS AS WELL.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* FREEZING RAIN DEVELOPS TOWARD MIDDAY...POSSIBLY STARTING AS A
PERIOD OF SLEET
* CIGS/VSBY FALLING TO MVFR SUNDAY AFTERNOON AND EVENTUALLY IFR
SUNDAY EVENING
* FREEZING RAIN CHANGES TO RAIN LATE THIS AFTERNOON OR EARLY THIS
EVENING AS TEMPS RISE ABOVE FREEZING
* IFR/LIFR CONDITIONS LIKELY FROM MID/LATE EVENING THROUGH
OVERNIGHT TONIGHT
IZZI
//DISCUSSION...UPDATED 09Z...
HAVE NUDGED THE TIMING OF THE ARRIVAL OF THE PRECIP UP JUST A BIT
BASED ON RADAR TRENDS OF LARGE SHIELD OF PRECIPITATION OVER MO
MARCHING RATHER STEADILY NORTHEASTWARD. TEMPERATURES HAVE BEEN
RISING QUITE QUICKLY AHEAD OF THE PRECIPITATION WITH PRECIP ALMOST
ENTIRELY RAIN AT THIS TIME. DRIER AIR IN ADVANCE OF THE RAIN OVER
NORTHERN ILLINOIS COULD SLOW ITS PROGRESSION A BIT BY EATING AWAY
SOME OF THE LEADING EDGE AND EVAPORATIVE COOLING COULD BE ENOUGH
TO COOL TEMPS SLIGHTLY. GIVEN UPSTREAM TRENDS CONFIDENCE IN
FREEZING TODAY HAS WANED SOME AND THE TREND OF TEMPS RISING
QUICKLY AHEAD OF THE PRECIP CONTINUES THE THREAT OF FZRA/PL MAY BE
LOWER OR THE TIME WINDOW OF OCCURANCE SHORTER. PARTICULARLY
CONCERNING SEEING THE LATEST RAP MODEL SHOWING TEMPS NEARING 40F
AHEAD OF THE PRECIP OVER THE CHICAGO AREA...IF THIS VERIFIES THERE
MAY NOT BE MUCH FROZEN/FREEZING PRECIP. NOT PLANNING ANY BIG
OVERHAULS TO THE TAF FORECAST NOW BASED ON THAT ONE MODELS BUT
WILL CONTINUE TO CLOSELY MONITOR TRENDS. HAVE SHORTENED THE
FORECAST DURATION OF THE FZRZ IN THE TAFS WITH THIS UPDATE CYCLE.
IZZI
UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE AND WARM FRONT LIFTING NORTH ACROSS THE
REGION WILL RESULT IN A PERIOD MIXED PRECIPIATION SUNDAY AFTERNOON
BEFORE CHANGING TO ALL RAIN SUNDAY EVENING. FORECAST SOUNDINGS
SUGGEST THAT SATURATION WILL TAKE PLACE FROM TOP-DOWN WHICH
SUGGESTS THAT PRECIP COULD BRIEFLY START AS A PERIOF OF SLEET
BEFORE STRONG WARM AIR ADVECTION RESULTS IN A CHANGE OVER TO
FREEZING RAIN. CONFIDENCE IS LOW ON HOW QUICKLY SFC TEMPS WILL
RISE ABOVE FREEZING BUT DOES APPEAR AS THOUGH AT LEAST A COUPLE
HOURS...POSSIBLY LONGER...OF FZRA IS LIKELY LATER SUNDAY AFTERNOON
INTO EARLY SUNDAY EVENING. STEADY RAIN EXPECTED TO END SUNDAY
EVENING BUT DRIZZLE AND PERIODIC LIGHT RAIN COULD LINGER THROUGH
THE NIGHT SUNDAY.
INITIALLY VFR CIGS SHOULD BUILD DOWN TO MVFR AND EVENTUALLY IFR
SUNDAY AFTERNOON/EVENING...WITH CORRESPONDING REDUCTION IN VSBY
EXPECTED...ESPECIALLY SUNDAY EVENING AS CIGS LOWER AND SOME LIGHT
FOG/DRIZZLE DEVELOPS.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN START TIME OF PRECIP
* LOW-MEDIUM CONFIDENCE IN PRECIP TYPE TODAY
* HIGH CONFIDENCE IN ANY FREEZING PRECIP CHANGING TO ALL RAIN...BUT
LOW CONFIDENCE IN TIMING OF CHANGE OVER
* HIGH CONFIDENCE IN THE GENERAL CIG/VSBY TRENDS...BUT LOW
CONFIDENCE IN PRECISE TIMING
* HIGH CONFIDENCE IN WINDS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...IFR CIGS/VIS LIKELY WITH -RA/BR.
TUESDAY...SHRA/TSRA LIKELY. MVFR LIKELY/IFR POSSIBLE.
WEDNESDAY THROUGH FRIDAY...MVFR CIGS PROBABLE. A FEW PERIODIC
FLURRIES OR LIGHT SNOW SHOWERS POSSIBLE.
KREIN
&&
.MARINE...
216 AM CST
AN ACTIVE PERIOD LIES AHEAD ACROSS THE LAKE BUT AT THIS POINT PEAK
WIND SPEEDS LOOK TO PRIMARILY REMAIN BELOW GALE FORCE THOUGH THERE
MAY BE A FEW PERIODS THAT COME CLOSE. HIGH PRESSURE SPREAD FROM
WESTERN QUEBEC INTO THE OHIO VALLEY. LOW PRESSURE IS DEVELOPING OVER
THE SOUTHERN HIGH PLAINS AND WILL TRACK NORTHEASTWARD AND CROSS
NORTHERN LAKE MICHIGAN MONDAY AFTERNOON. SOUTH WINDS WILL INCREASE
TODAY AS THE INFLUENCE OF HIGH PRESSURE DEPARTS AND PRESSURE START
TO FALL AHEAD OF THE LOW. EXPECT SPEEDS OF AROUND 30 KT LATER THIS
AFTERNOON INTO THE EVENING ESPECIALLY OVER THE SOUTHERN PART OF THE
LAKE BEFORE MUCH WARMER AIR TAKES OVER ALOFT SETTING UP AN
INVERSION. THIS INVERSION LOOKS TO ALLOW WINDS TO EASE OVERNIGHT AND
MONDAY MORNING KEEPING THE STRONGER 40 KT SPEEDS FROM REACHING THE
LAKE SURFACE. WILL CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS
FOR THE NEARSHORE BUT MAY BE ABLE TO MOVE THE END TIME EARLIER FOR
THE INDIANA WATERS BUT WILL HOLD OFF FOR NOW AND LET LATER SHIFTS
SEE HOW THINGS MATERIALIZE. THE SURFACE LOW WILL CROSS THE
NORTHERN PART OF THE LAKE MONDAY AFTERNOON ALLOWING LIGHT WINDS
FOR A TIME NORTH AS THE DIRECTION SHIFTS SOUTHWESTERLY ACROSS THE
SOUTH. WEAK RIDGING THEN QUICKLY CROSSES THE LAKE MONDAY EVENING
KEEPING LIGHT WINDS IN PLACE BUT ANOTHER SURFACE LOW WILL BE
MOVING NORTHEASTWARD FROM THE SOUTHERN PLAINS RESULTING IN A QUICK
SHIFT TO INCREASING SOUTHWESTERLY WINDS. AN INVERSION WILL REMAIN
IN PLACE WITH MUCH WARMER AIR OVER THE LAKE SO THE 40+ KT SPEEDS
AT AROUND 1000 FT ABOVE THE SURFACE WILL REMAIN THERE WHILE LAKE
LEVEL WINDS ARE HELD TO LESS THAN 30 KT CENTRAL AND SOUTH...WITH
LIGHTER WINDS FAR NORTH IN THE WEAK PRESSURE GRADIENT IN THE
TROUGH OF THE APPROACHING LOW. THERE IS SOME INDICATION OF THE LOW
SHIFTING FURTHER NORTH WHICH WOULD THEN LEAD TO MORE OF THE LAKE
SEEING THESE STRONGER WINDS. A SECOND LOW FORMS SOUTHEAST OF THE
LAKE LATER TUESDAY AS A COLD FRONT CROSSES THE LAKE SHIFTING WINDS
TO THE NORTHWEST. MUCH COLDER AIR WILL SPILL IN BEHIND THE FRONT
BRINGING UNSTABLE AIR BACK OVER THE LAKE. AT THIS POINT WIND
SPEEDS DO NOT LOOK TO INCREASE MARKEDLY DESPITE THE COLD ADVECTION
BUT THERE IS STILL SOME UNCERTAINTY IN HOW THE TWO LOWS EVOLVE SO
THERE IS SOME POTENTIAL FOR INCREASED WINDS OVER WHAT IS CURRENTLY
FORECAST TUESDAY NIGHT AND WEDNESDAY.
SEVERAL WEAKER TROUGHS WILL CROSS THE REGION FROM WEDNESDAY THROUGH
EARLY NEXT WEEKEND. WINDS WILL GENERALLY REMAIN WESTERLY WITH
FLUCTUATIONS FROM SOUTHWEST TO NORTHWEST AS EACH TROUGH PASSES WITH
PERIODIC INCREASES IN SPEEDS. WILL NEED TO MONITOR THE STRENGTH OF
THESE AS IT WOULD NOT TAKE MUCH FOR THEM TO PRODUCE AT LEAST SHORT
PERIODS OF GALES BUT FOR NOW WILL KEEP PEAK SPEEDS AROUND 30 KT.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019-ILZ021-
ILZ032-ILZ039...9 AM SUNDAY TO 4 PM SUNDAY.
FREEZING RAIN ADVISORY...ILZ012-ILZ013-ILZ014-ILZ020-ILZ022-
ILZ023-ILZ033...11 AM SUNDAY TO 4 PM SUNDAY.
FREEZING RAIN ADVISORY...ILZ005-ILZ006...11 AM SUNDAY TO 7 PM
SUNDAY.
FREEZING RAIN ADVISORY...ILZ003-ILZ004...9 AM SUNDAY TO 7 PM
SUNDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...11
AM SUNDAY TO 4 PM SUNDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...NOON SUNDAY TO 4
AM MONDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SUNDAY TO 10
AM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
145 PM EST SUN JAN 27 2013
.AVIATION...
A SURGE OF MILD AND MOIST AIR AHEAD OF AN ADVANCING SYSTEM WILL
CAUSE FREEZING RAIN TO DEVELOP EARLY IN THE TAF PERIOD. THE LATEST
DOPPLER RADAR DUAL POLARITY IMAGES SUPPORT A MIX OF SLEET IN THE
UPSTREAM HEAVIER RETURNS. THE CHANGEOVER FROM FREEZING RAIN TO
RAIN REALLY CHALLENGING WITH GROUND SURFACES BELOW FREEZING AND
WET BULB TEMPS STILL WELL DOWN IN THE 20S. AT 135 PM...WE OBSERVED
A MIX OF SLEET AND FREEZING RAIN HERE AT OUR OFFICE. WITH ALL
CONSIDERED...PLANNED TO STAY CONSERVATIVE WITH GENERALLY A SLOWER
CHANGEOVER TIME FROM FREEZING RAIN TO SLEET IN THE TAFS. THE 02Z
TAF CHANGEOVER TIME AT FWA MAY BE TOO SOON AS ALSO THE 03Z TIME AT
SBN.
&&
.PREV DISCUSSION... /ISSUED 429 AM EST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST CONCERN FOR THE SHORT TERM WILL BE THE POTENTIAL OF A
PERIOD OF FREEZING RAIN THIS AFTERNOON INTO THIS MAINLY THIS EVENING.
ELEVATED ECHOES EVIDENT ON RADAR MOSAIC THIS MORNING FROM NORTH
CENTRAL WISCONSIN INTO SOUTHERN LOWER MICHIGAN ASSOCIATED WITH
LEADING EDGE OF STRONGER 850-700 HPA THETA ADV. THIS ELEVATED
FORCING THIS MORNING WILL ONLY SERVE IN TOP DOWN SATURATION WITH
DEEPER MOISTURE AND STRONGER LOW LEVEL THEATE ADVECTION SITUATED
BACK ACROSS THE SOUTHERN/CENTRAL PLAINS WHERE RAIN HAS BEEN
EXPANDING IN COVERAGE. 06Z RAP LOW LEVEL MOISTURE TRANSPORT PROGS
DEPICTING STRONGEST 925 HPA TRANSPORT VECTORS INTO MISSOURI/SOUTHERN
IOWA THIS AFTERNOON WITH ADVECTION SOMEWHAT DELAYED ACROSS LOCAL
AREA DUE TO WEAK LOW LEVEL SOUTHEAST WIND COMPONENT ASSOCIATED WITH
DEPARTING LOW LEVEL ANTICYCLONE.
IT STILL APPEARS CHANCES OF PRECIP WILL INCREASE ACROSS WESTERN
PORTIONS OF THE FORECAST AREA TOWARD THE 21Z TIMEFRAME BUT
PRECIPITATION SHOULD BE INITIALLY VERY LIGHT. CANNOT COMPLETELY
DISCOUNT A VERY BRIEF PERIOD OF A SNOW/SLEET MIX DUE TO WET BULB
EFFECTS...BUT STRENGTH OF LOW LEVEL WARM/MOIST ADVECTION VIA AN
APPROACHING 60 KNOT LOW LEVEL JET AXIS SHOULD SUPPORT PRECIP TYPE OF
MAINLY SLEET/FREEZING RAIN MIX BY THE TIME MORE APPRECIABLE PRECIP
RATES WOULD BE OBSERVED LATE THIS AFTERNOON AS LOW LEVELS SATURATE.
STRENGTH OF LOW LEVEL MOISTURE ADVECTION AND INSPECTION OF RAP/NAM
FORECAST SOUNDINGS EVEN OFFERS SOME QUESTION AS TO THE POSSIBILITY
THAT ONCE LOW LEVEL SATURATION OCCURS...PRECIPITATION TYPE MAY BE
MAINLY IN THE FORM OF RAIN ACROSS THE FAR SOUTH/SOUTHWEST. HAVE
CONTINUED TO RELY MORE ON NAM IDEA IN TERMS OF INITIAL LOW LEVEL
SATURATION/WET BULB PROCESSES WITH GFS OFTEN EXHIBITING A MOIST BIAS
IN RAPID LOW LEVEL MOISTENING WITH THIS TYPE OF SETUP.
IT STILL APPEARS AS THOUGH MOST LOCATIONS MAY RECEIVE A 2 TO 4 HOUR
PERIOD OF MIXED PRECIP AND FREEZING RAIN THREAT BEFORE CHANGING OVER
TO RAIN. THE BEST CHANCE FOR THE LONGEST DURATION OF PROFILES
SUPPORTIVE OF FREEZING STILL APPEARS TO BE ACROSS THE FAR NORTHEAST
WHICH IS ALSO SUPPORTED BY SREF PROBABILISTIC PRODUCTS. GIVEN
INCREASING CONFIDENCE THAT PRIMARY IMPACTS WOULD BE FROM A PERIOD OF
FREEZING RAIN WITH LITTLE IF ANY SLEET ACCUMULATION...WILL REPLACE
THE WINTER WEATHER ADVISORY WITH A FREEZING RAIN ADVISORY. LATEST
DATA CONTINUES TO SUGGEST THAT DURATION OF FREEZING PRECIP MAY BE
SLIGHTLY SHORTER THAN PREVIOUSLY ANTICIPATED...ESPECIALLY ACROSS
SOUTHERN HALF OF THE AREA BUT WILL KEEP TIMING OF WSW THE SAME FOR
BOTH SEGMENTS AND OPT TO HOLD ONTO SOUTHERN PORTIONS OF THE ADVISORY
AT THIS TIME. EVEN AFTER TEMPERATURES WARM ABOVE FREEZING THIS
EVENING...RECENT VERY COLD TEMPS AND COLD GROUND CONDITIONS MAY
STILL SUPPORT SOME FREEZING ON ROADWAYS FOR A TIME AFTER TEMPS RISE
ABOVE FREEZING...ESPECIALLY ACROSS NORTHERN HALF. HAVE MAINTAINED
ICE ACCUMULATIONS IN THE 0.05 TO 0.1 INCH RANGE...WITH THE HIGHER
END OF THIS RANGE EXPECTED ACROSS FAR NORTH/NORTHEAST.
BROAD ISENTROPIC UPGLIDE TO CONTINUE INTO MONDAY WITH ANOTHER LOW
AMPLITUDE MID LEVEL WAVE TRACKING ACROSS THE GREAT LAKES REGION. NOT
MUCH ORGANIZATION EXPECTED TO PRECIP ON MONDAY BUT WITH BROAD
ISENTROPIC UPGLIDE AND WEAK MID LEVEL FORCING WILL CONTINUE TO CARRY
HIGH RAIN POPS THROUGH MONDAY/MONDAY NIGHT. NEXT WARM FRONTAL SURGE
ASSOCIATED WITH AMPLIFYING UPSTREAM LONGWAVE TROUGH SHOULD RESULT IN
INCREASED PRECIP CHANCES MONDAY NIGHT WITH EVEN THE POSSIBILITY OF
SOME EMBEDDED THUNDER ACROSS THE WEST LATE IN THE NIGHT. TEMPS
SHOULD EXHIBIT NON DIURNAL TENDENCIES MONDAY NIGHT WITH THE WARM
FRONT...POSSIBLY EVEN RISING INTO THE LOWER 50S ACROSS THE SOUTH BY
MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
PROGRESSIVE HIGH AMPLITUDE TROUGH WILL BE FIRMLY IN PLACE ACROSS THE
ROCKIES AT THE START OF THE PERIOD TUESDAY WITH A REMARKABLE 150+
KNOT MERIDIONAL UPPER LEVEL JET ON THE DOWNSTREAM SIDE. THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS IMPRESSIVE AND SEVERAL WAVES
OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG IT AS THE TROUGH
INCHES ACROSS OUR REGION. BUT FIRST...OUR CWA WILL BE FIRMLY IN
SOUTHWEST FLOW ON TUESDAY WITH CONTINUED WARM/MOIST AIR ADVECTION.
850MB DEWPOINTS CLIMB TO AROUND 10C WITH PW VALUES WELL OVER AN INCH
BY LATE TUESDAY. SURFACE DEWPOINTS ALSO STILL EXPECTED TO CLIMB INTO
THE MID 50S...MAKING FOR A VERY WARM DAY BY JANUARY STANDARDS. IN
FACT...LATEST GUIDANCE IS SHOWING HIGHS NEAR OR ABOVE THE RECORDS
(58 FOR SBN AND 62 FOR FWA...BOTH SET IN 1914). BUMPED UP HIGHS BUT
WILL LEAVE THEM JUST BELOW 60F FOR MOST AREAS GIVEN CONCERNS OVER
STILL VERY COLD GROUND TEMPERATURES. PRECIP CHANCES/AMOUNTS DURING
THE DAY TUESDAY WILL DEPEND ON TIMING AND EVOLUTION OF LOW LEVEL JET
WITH RAGGED ISENTROPIC ASCENT SUPPORTING MAINLY JUST SCATTERED
SHOWERS UNTIL THE FRONT ARRIVES. MUCH BETTER FORCING WILL ARRIVE
LATE TUESDAY WITH STRONG MIDLEVEL HEIGHT FALLS AND VERY FAVORABLE
UPPER LEVEL JET DYNAMICS. THIS WILL FAVOR SURFACE CYCLOGENESIS
SOMEWHERE OVER THE GREAT LAKES REGION WITH COPIOUS AMOUNTS OF
RAINFALL ALONG THE TRAILING COLD FRONT. LATEST NAM BUFR SOUNDINGS
ARE ALSO MUCH MORE OMINOUS REGARDING THUNDER POTENTIAL WITH ALMOST
1000 J/KG OF ELEVATED CAPE. THIS IS PROBABLY OVERDONE BUT GIVEN THE
STRENGTH OF THE DEVELOPING LLJ COULD EASILY SEE SOME THUNDER
OCCURRING LATE TUESDAY AND WILL ADD MENTION TO THE FORECAST. GIVEN
THE POTENTIAL FOR CONVECTION COUPLED WITH STRONG WARM/MOIST AIR
ADVECTION AHEAD OF THE FRONT AND EXCELLENT FORCING ALOFT...QPF
AMOUNTS IN EXCESS OF AN INCH ARE POSSIBLE TUESDAY NIGHT. THIS
CERTAINLY RAISES THE CONCERN FOR FLOODING WITH MELTING SNOWPACK IN
THE NORTH AND LIKELY STILL FROZEN GROUND.
ARCTIC AIR RETURNS BY LATE WEDNESDAY WITH THE REESTABLISHMENT OF
NORTHWEST FLOW AND CAA. COLDEST AIR WILL TAKE SOME TIME TO FILTER
INTO THE REGION SO THERE MAY BE A BRIEF LULL IN THE PRECIP BEFORE
THE LAKE EFFECT GETS GOING BUT WILL MAINTAIN HIGH CHANCE POPS ON
WEDNESDAY GIVEN UNCERTAINTY IN EXACT TIMING OF EXITING FRONT. WILL
ALSO LIKELY BE AN ATYPICAL DIURNAL CURVE WITH AFTERNOON TEMPS
FALLING FROM MORNING HIGHS AROUND 40F. LAKE RESPONSE DOESNT TRULY
LIGHT UP UNTIL THURSDAY WITH THE APPROACH OF A VIGOROUS SHORTWAVE
AND 850MB TEMPS BOTTOMING OUT IN THE LOW -20S. LAKE EFFECT SNOW WILL
CONTINUE THROUGH FRIDAY BUT A WNW FETCH WILL LIKELY CONFINE BIGGEST
IMPACTS TO OUR EXTREME NORTHERN COUNTIES. HIGH TEMPS DURING THIS
PERIOD WILL LIKELY STRUGGLE TO GET ABOVE 20F GIVEN AFOREMENTIONED
850MB TEMPS. LOW LEVEL RIDGE AXIS SHIFTS EAST ON FRIDAY BUT ONLY A
BRIEF RESPITE FROM PRECIP CHANCES BEFORE ANOTHER CLIPPER SYSTEM
DIVES ACROSS THE REGION ON SATURDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FLOOD WATCH FROM MONDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
INZ003>009-012>018-020-022>027-032>034.
FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR INZ006-007-009.
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST /11 PM CST/ TONIGHT
FOR INZ003>005-008-012>018-020-022>027-032>034.
MI...FLOOD WATCH FROM MONDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
MIZ077>081.
FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR MIZ078>081.
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ077.
OH...FLOOD WATCH FROM MONDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
OHZ001-002-004-005-015-016-024-025.
FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR OHZ001-002-004-005-015-016-024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST MONDAY FOR LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...SKIPPER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
647 AM EST SUN JAN 27 2013
.AVIATION...
12Z TAFS...STRONG LOW LEVEL WARM/MOIST ADVECTION WILL OVERSPREAD
NORTHERN INDIANA LATER THIS AFTERNOON. REGIONAL RADAR MOSAIC
ALREADY INDICATING LEADING EDGE OF PRECIP SHIELD REACHING WEST
CENTRAL IOWA INTO EASTERN MISSOURI AT 11Z. STRONGER LOW LEVEL
MOISTURE TRANSPORT OVER NEXT SEVERAL HOURS SHOULD REMAIN ACROSS
PORTIONS OF NORTHEAST MISSOURI INTO EASTERN IOWA/NORTHERN ILLINOIS
SO SOME QUESTION EXISTS AS TO THE PROGRESSION OF THE SOUTHERN
PERIPHERY OF THIS PRECIP EASTERN MISSOURI. INITIALLY VERY DRY AIR
MASS ACROSS LOCAL AREA SHOULD STILL DELAY ONSET OF PRECIP TO THE
21Z-23Z TIMEFRAME...PERHAPS JUST A BIT SOONER AT KSBN. PROFILES
SHOULD SUPPORT A MIX OF SLEET/FREEZING RAIN AT ONSET WITH AN
EXPECTED PERIOD OF MAINLY FREEZING RAIN EARLY THIS EVENING BEFORE
THE AXIS OF THE STRONG LOW LEVEL JET TO THE WEST ALLOWS PROFILES
WARM ENOUGH FOR RAIN. RAPIDLY DETERIORATING CIGS TO IFR ARE ALSO
EXPECTED EARLY THIS EVENING...AND TO LIFR LATE EVENING. HAVE ALSO
ADDED LLWS MENTION IN ASSOCIATION WITH THIS LOW LEVEL JET AFTER
04Z.
&&
.PREV DISCUSSION... /ISSUED 429 AM EST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST CONCERN FOR THE SHORT TERM WILL BE THE POTENTIAL OF A
PERIOD OF FREEZING RAIN THIS AFTERNOON INTO THIS MAINLY THIS EVENING.
ELEVATED ECHOES EVIDENT ON RADAR MOSAIC THIS MORNING FROM NORTH
CENTRAL WISCONSIN INTO SOUTHERN LOWER MICHIGAN ASSOCIATED WITH
LEADING EDGE OF STRONGER 850-700 HPA THETA ADV. THIS ELEVATED
FORCING THIS MORNING WILL ONLY SERVE IN TOP DOWN SATURATION WITH
DEEPER MOISTURE AND STRONGER LOW LEVEL THEATE ADVECTION SITUATED
BACK ACROSS THE SOUTHERN/CENTRAL PLAINS WHERE RAIN HAS BEEN
EXPANDING IN COVERAGE. 06Z RAP LOW LEVEL MOISTURE TRANSPORT PROGS
DEPICTING STRONGEST 925 HPA TRANSPORT VECTORS INTO MISSOURI/SOUTHERN
IOWA THIS AFTERNOON WITH ADVECTION SOMEWHAT DELAYED ACROSS LOCAL
AREA DUE TO WEAK LOW LEVEL SOUTHEAST WIND COMPONENT ASSOCIATED WITH
DEPARTING LOW LEVEL ANTICYCLONE.
IT STILL APPEARS CHANCES OF PRECIP WILL INCREASE ACROSS WESTERN
PORTIONS OF THE FORECAST AREA TOWARD THE 21Z TIMEFRAME BUT
PRECIPITATION SHOULD BE INITIALLY VERY LIGHT. CANNOT COMPLETELY
DISCOUNT A VERY BRIEF PERIOD OF A SNOW/SLEET MIX DUE TO WET BULB
EFFECTS...BUT STRENGTH OF LOW LEVEL WARM/MOIST ADVECTION VIA AN
APPROACHING 60 KNOT LOW LEVEL JET AXIS SHOULD SUPPORT PRECIP TYPE OF
MAINLY SLEET/FREEZING RAIN MIX BY THE TIME MORE APPRECIABLE PRECIP
RATES WOULD BE OBSERVED LATE THIS AFTERNOON AS LOW LEVELS SATURATE.
STRENGTH OF LOW LEVEL MOISTURE ADVECTION AND INSPECTION OF RAP/NAM
FORECAST SOUNDINGS EVEN OFFERS SOME QUESTION AS TO THE POSSIBILITY
THAT ONCE LOW LEVEL SATURATION OCCURS...PRECIPITATION TYPE MAY BE
MAINLY IN THE FORM OF RAIN ACROSS THE FAR SOUTH/SOUTHWEST. HAVE
CONTINUED TO RELY MORE ON NAM IDEA IN TERMS OF INITIAL LOW LEVEL
SATURATION/WET BULB PROCESSES WITH GFS OFTEN EXHIBITING A MOIST BIAS
IN RAPID LOW LEVEL MOISTENING WITH THIS TYPE OF SETUP.
IT STILL APPEARS AS THOUGH MOST LOCATIONS MAY RECEIVE A 2 TO 4 HOUR
PERIOD OF MIXED PRECIP AND FREEZING RAIN THREAT BEFORE CHANGING OVER
TO RAIN. THE BEST CHANCE FOR THE LONGEST DURATION OF PROFILES
SUPPORTIVE OF FREEZING STILL APPEARS TO BE ACROSS THE FAR NORTHEAST
WHICH IS ALSO SUPPORTED BY SREF PROBABILISTIC PRODUCTS. GIVEN
INCREASING CONFIDENCE THAT PRIMARY IMPACTS WOULD BE FROM A PERIOD OF
FREEZING RAIN WITH LITTLE IF ANY SLEET ACCUMULATION...WILL REPLACE
THE WINTER WEATHER ADVISORY WITH A FREEZING RAIN ADVISORY. LATEST
DATA CONTINUES TO SUGGEST THAT DURATION OF FREEZING PRECIP MAY BE
SLIGHTLY SHORTER THAN PREVIOUSLY ANTICIPATED...ESPECIALLY ACROSS
SOUTHERN HALF OF THE AREA BUT WILL KEEP TIMING OF WSW THE SAME FOR
BOTH SEGMENTS AND OPT TO HOLD ONTO SOUTHERN PORTIONS OF THE ADVISORY
AT THIS TIME. EVEN AFTER TEMPERATURES WARM ABOVE FREEZING THIS
EVENING...RECENT VERY COLD TEMPS AND COLD GROUND CONDITIONS MAY
STILL SUPPORT SOME FREEZING ON ROADWAYS FOR A TIME AFTER TEMPS RISE
ABOVE FREEZING...ESPECIALLY ACROSS NORTHERN HALF. HAVE MAINTAINED
ICE ACCUMULATIONS IN THE 0.05 TO 0.1 INCH RANGE...WITH THE HIGHER
END OF THIS RANGE EXPECTED ACROSS FAR NORTH/NORTHEAST.
BROAD ISENTROPIC UPGLIDE TO CONTINUE INTO MONDAY WITH ANOTHER LOW
AMPLITUDE MID LEVEL WAVE TRACKING ACROSS THE GREAT LAKES REGION. NOT
MUCH ORGANIZATION EXPECTED TO PRECIP ON MONDAY BUT WITH BROAD
ISENTROPIC UPGLIDE AND WEAK MID LEVEL FORCING WILL CONTINUE TO CARRY
HIGH RAIN POPS THROUGH MONDAY/MONDAY NIGHT. NEXT WARM FRONTAL SURGE
ASSOCIATED WITH AMPLIFYING UPSTREAM LONGWAVE TROUGH SHOULD RESULT IN
INCREASED PRECIP CHANCES MONDAY NIGHT WITH EVEN THE POSSIBILITY OF
SOME EMBEDDED THUNDER ACROSS THE WEST LATE IN THE NIGHT. TEMPS
SHOULD EXHIBIT NON DIURNAL TENDENCIES MONDAY NIGHT WITH THE WARM
FRONT...POSSIBLY EVEN RISING INTO THE LOWER 50S ACROSS THE SOUTH BY
MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
PROGRESSIVE HIGH AMPLITUDE TROUGH WILL BE FIRMLY IN PLACE ACROSS THE
ROCKIES AT THE START OF THE PERIOD TUESDAY WITH A REMARKABLE 150+
KNOT MERIDIONAL UPPER LEVEL JET ON THE DOWNSTREAM SIDE. THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS IMPRESSIVE AND SEVERAL WAVES
OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG IT AS THE TROUGH
INCHES ACROSS OUR REGION. BUT FIRST...OUR CWA WILL BE FIRMLY IN
SOUTHWEST FLOW ON TUESDAY WITH CONTINUED WARM/MOIST AIR ADVECTION.
850MB DEWPOINTS CLIMB TO AROUND 10C WITH PW VALUES WELL OVER AN INCH
BY LATE TUESDAY. SURFACE DEWPOINTS ALSO STILL EXPECTED TO CLIMB INTO
THE MID 50S...MAKING FOR A VERY WARM DAY BY JANUARY STANDARDS. IN
FACT...LATEST GUIDANCE IS SHOWING HIGHS NEAR OR ABOVE THE RECORDS
(58 FOR SBN AND 62 FOR FWA...BOTH SET IN 1914). BUMPED UP HIGHS BUT
WILL LEAVE THEM JUST BELOW 60F FOR MOST AREAS GIVEN CONCERNS OVER
STILL VERY COLD GROUND TEMPERATURES. PRECIP CHANCES/AMOUNTS DURING
THE DAY TUESDAY WILL DEPEND ON TIMING AND EVOLUTION OF LOW LEVEL JET
WITH RAGGED ISENTROPIC ASCENT SUPPORTING MAINLY JUST SCATTERED
SHOWERS UNTIL THE FRONT ARRIVES. MUCH BETTER FORCING WILL ARRIVE
LATE TUESDAY WITH STRONG MIDLEVEL HEIGHT FALLS AND VERY FAVORABLE
UPPER LEVEL JET DYNAMICS. THIS WILL FAVOR SURFACE CYCLOGENESIS
SOMEWHERE OVER THE GREAT LAKES REGION WITH COPIOUS AMOUNTS OF
RAINFALL ALONG THE TRAILING COLD FRONT. LATEST NAM BUFR SOUNDINGS
ARE ALSO MUCH MORE OMINOUS REGARDING THUNDER POTENTIAL WITH ALMOST
1000 J/KG OF ELEVATED CAPE. THIS IS PROBABLY OVERDONE BUT GIVEN THE
STRENGTH OF THE DEVELOPING LLJ COULD EASILY SEE SOME THUNDER
OCCURRING LATE TUESDAY AND WILL ADD MENTION TO THE FORECAST. GIVEN
THE POTENTIAL FOR CONVECTION COUPLED WITH STRONG WARM/MOIST AIR
ADVECTION AHEAD OF THE FRONT AND EXCELLENT FORCING ALOFT...QPF
AMOUNTS IN EXCESS OF AN INCH ARE POSSIBLE TUESDAY NIGHT. THIS
CERTAINLY RAISES THE CONCERN FOR FLOODING WITH MELTING SNOWPACK IN
THE NORTH AND LIKELY STILL FROZEN GROUND.
ARCTIC AIR RETURNS BY LATE WEDNESDAY WITH THE REESTABLISHMENT OF
NORTHWEST FLOW AND CAA. COLDEST AIR WILL TAKE SOME TIME TO FILTER
INTO THE REGION SO THERE MAY BE A BRIEF LULL IN THE PRECIP BEFORE
THE LAKE EFFECT GETS GOING BUT WILL MAINTAIN HIGH CHANCE POPS ON
WEDNESDAY GIVEN UNCERTAINTY IN EXACT TIMING OF EXITING FRONT. WILL
ALSO LIKELY BE AN ATYPICAL DIURNAL CURVE WITH AFTERNOON TEMPS
FALLING FROM MORNING HIGHS AROUND 40F. LAKE RESPONSE DOESNT TRULY
LIGHT UP UNTIL THURSDAY WITH THE APPROACH OF A VIGOROUS SHORTWAVE
AND 850MB TEMPS BOTTOMING OUT IN THE LOW -20S. LAKE EFFECT SNOW WILL
CONTINUE THROUGH FRIDAY BUT A WNW FETCH WILL LIKELY CONFINE BIGGEST
IMPACTS TO OUR EXTREME NORTHERN COUNTIES. HIGH TEMPS DURING THIS
PERIOD WILL LIKELY STRUGGLE TO GET ABOVE 20F GIVEN AFOREMENTIONED
850MB TEMPS. LOW LEVEL RIDGE AXIS SHIFTS EAST ON FRIDAY BUT ONLY A
BRIEF RESPITE FROM PRECIP CHANCES BEFORE ANOTHER CLIPPER SYSTEM
DIVES ACROSS THE REGION ON SATURDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR INZ006-007-009.
FREEZING RAIN ADVISORY FROM 3 PM EST /2 PM CST/ THIS AFTERNOON
TO MIDNIGHT EST /11 PM CST/ TONIGHT FOR INZ003>005-008-
012>018-020-022>027-032>034.
MI...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR MIZ078>081.
FREEZING RAIN ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
TONIGHT FOR MIZ077.
OH...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR OHZ001-002-004-005-015-016-024-025.
LM...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST MONDAY
FOR LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
429 AM EST SUN JAN 27 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST CONCERN FOR THE SHORT TERM WILL BE THE POTENTIAL OF A
PERIOD OF FREEZING RAIN THIS AFTERNOON INTO THIS MAINLY THIS EVENING.
ELEVATED ECHOES EVIDENT ON RADAR MOSAIC THIS MORNING FROM NORTH
CENTRAL WISCONSIN INTO SOUTHERN LOWER MICHIGAN ASSOCIATED WITH
LEADING EDGE OF STRONGER 850-700 HPA THETA ADV. THIS ELEVATED
FORCING THIS MORNING WILL ONLY SERVE IN TOP DOWN SATURATION WITH
DEEPER MOISTURE AND STRONGER LOW LEVEL THEATE ADVECTION SITUATED
BACK ACROSS THE SOUTHERN/CENTRAL PLAINS WHERE RAIN HAS BEEN
EXPANDING IN COVERAGE. 06Z RAP LOW LEVEL MOISTURE TRANSPORT PROGS
DEPICTING STRONGEST 925 HPA TRANSPORT VECTORS INTO MISSOURI/SOUTHERN
IOWA THIS AFTERNOON WITH ADVECTION SOMEWHAT DELAYED ACROSS LOCAL
AREA DUE TO WEAK LOW LEVEL SOUTHEAST WIND COMPONENT ASSOCIATED WITH
DEPARTING LOW LEVEL ANTICYCLONE.
IT STILL APPEARS CHANCES OF PRECIP WILL INCREASE ACROSS WESTERN
PORTIONS OF THE FORECAST AREA TOWARD THE 21Z TIMEFRAME BUT
PRECIPITATION SHOULD BE INITIALLY VERY LIGHT. CANNOT COMPLETELY
DISCOUNT A VERY BRIEF PERIOD OF A SNOW/SLEET MIX DUE TO WET BULB
EFFECTS...BUT STRENGTH OF LOW LEVEL WARM/MOIST ADVECTION VIA AN
APPROACHING 60 KNOT LOW LEVEL JET AXIS SHOULD SUPPORT PRECIP TYPE OF
MAINLY SLEET/FREEZING RAIN MIX BY THE TIME MORE APPRECIABLE PRECIP
RATES WOULD BE OBSERVED LATE THIS AFTERNOON AS LOW LEVELS SATURATE.
STRENGTH OF LOW LEVEL MOISTURE ADVECTION AND INSPECTION OF RAP/NAM
FORECAST SOUNDINGS EVEN OFFERS SOME QUESTION AS TO THE POSSIBILITY
THAT ONCE LOW LEVEL SATURATION OCCURS...PRECIPITATION TYPE MAY BE
MAINLY IN THE FORM OF RAIN ACROSS THE FAR SOUTH/SOUTHWEST. HAVE
CONTINUED TO RELY MORE ON NAM IDEA IN TERMS OF INITIAL LOW LEVEL
SATURATION/WET BULB PROCESSES WITH GFS OFTEN EXHIBITING A MOIST BIAS
IN RAPID LOW LEVEL MOISTENING WITH THIS TYPE OF SETUP.
IT STILL APPEARS AS THOUGH MOST LOCATIONS MAY RECEIVE A 2 TO 4 HOUR
PERIOD OF MIXED PRECIP AND FREEZING RAIN THREAT BEFORE CHANGING OVER
TO RAIN. THE BEST CHANCE FOR THE LONGEST DURATION OF PROFILES
SUPPORTIVE OF FREEZING STILL APPEARS TO BE ACROSS THE FAR NORTHEAST
WHICH IS ALSO SUPPORTED BY SREF PROBABILISTIC PRODUCTS. GIVEN
INCREASING CONFIDENCE THAT PRIMARY IMPACTS WOULD BE FROM A PERIOD OF
FREEZING RAIN WITH LITTLE IF ANY SLEET ACCUMULATION...WILL REPLACE
THE WINTER WEATHER ADVISORY WITH A FREEZING RAIN ADVISORY. LATEST
DATA CONTINUES TO SUGGEST THAT DURATION OF FREEZING PRECIP MAY BE
SLIGHTLY SHORTER THAN PREVIOUSLY ANTICIPATED...ESPECIALLY ACROSS
SOUTHERN HALF OF THE AREA BUT WILL KEEP TIMING OF WSW THE SAME FOR
BOTH SEGMENTS AND OPT TO HOLD ONTO SOUTHERN PORTIONS OF THE ADVISORY
AT THIS TIME. EVEN AFTER TEMPERATURES WARM ABOVE FREEZING THIS
EVENING...RECENT VERY COLD TEMPS AND COLD GROUND CONDITIONS MAY
STILL SUPPORT SOME FREEZING ON ROADWAYS FOR A TIME AFTER TEMPS RISE
ABOVE FREEZING...ESPECIALLY ACROSS NORTHERN HALF. HAVE MAINTAINED
ICE ACCUMULATIONS IN THE 0.05 TO 0.1 INCH RANGE...WITH THE HIGHER
END OF THIS RANGE EXPECTED ACROSS FAR NORTH/NORTHEAST.
BROAD ISENTROPIC UPGLIDE TO CONTINUE INTO MONDAY WITH ANOTHER LOW
AMPLITUDE MID LEVEL WAVE TRACKING ACROSS THE GREAT LAKES REGION. NOT
MUCH ORGANIZATION EXPECTED TO PRECIP ON MONDAY BUT WITH BROAD
ISENTROPIC UPGLIDE AND WEAK MID LEVEL FORCING WILL CONTINUE TO CARRY
HIGH RAIN POPS THROUGH MONDAY/MONDAY NIGHT. NEXT WARM FRONTAL SURGE
ASSOCIATED WITH AMPLIFYING UPSTREAM LONGWAVE TROUGH SHOULD RESULT IN
INCREASED PRECIP CHANCES MONDAY NIGHT WITH EVEN THE POSSIBILITY OF
SOME EMBEDDED THUNDER ACROSS THE WEST LATE IN THE NIGHT. TEMPS
SHOULD EXHIBIT NON DIURNAL TENDENCIES MONDAY NIGHT WITH THE WARM
FRONT...POSSIBLY EVEN RISING INTO THE LOWER 50S ACROSS THE SOUTH BY
MORNING.
&&
.LONG TERM...TUESDAY THROUGH SATURDAY
PROGRESSIVE HIGH AMPLITUDE TROUGH WILL BE FIRMLY IN PLACE ACROSS THE
ROCKIES AT THE START OF THE PERIOD TUESDAY WITH A REMARKABLE 150+
KNOT MERIDIONAL UPPER LEVEL JET ON THE DOWNSTREAM SIDE. THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS IMPRESSIVE AND SEVERAL WAVES
OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG IT AS THE TROUGH
INCHES ACROSS OUR REGION. BUT FIRST...OUR CWA WILL BE FIRMLY IN
SOUTHWEST FLOW ON TUESDAY WITH CONTINUED WARM/MOIST AIR ADVECTION.
850MB DEWPOINTS CLIMB TO AROUND 10C WITH PW VALUES WELL OVER AN INCH
BY LATE TUESDAY. SURFACE DEWPOINTS ALSO STILL EXPECTED TO CLIMB INTO
THE MID 50S...MAKING FOR A VERY WARM DAY BY JANUARY STANDARDS. IN
FACT...LATEST GUIDANCE IS SHOWING HIGHS NEAR OR ABOVE THE RECORDS
(58 FOR SBN AND 62 FOR FWA...BOTH SET IN 1914). BUMPED UP HIGHS BUT
WILL LEAVE THEM JUST BELOW 60F FOR MOST AREAS GIVEN CONCERNS OVER
STILL VERY COLD GROUND TEMPERATURES. PRECIP CHANCES/AMOUNTS DURING
THE DAY TUESDAY WILL DEPEND ON TIMING AND EVOLUTION OF LOW LEVEL JET
WITH RAGGED ISENTROPIC ASCENT SUPPORTING MAINLY JUST SCATTERED
SHOWERS UNTIL THE FRONT ARRIVES. MUCH BETTER FORCING WILL ARRIVE
LATE TUESDAY WITH STRONG MIDLEVEL HEIGHT FALLS AND VERY FAVORABLE
UPPER LEVEL JET DYNAMICS. THIS WILL FAVOR SURFACE CYCLOGENESIS
SOMEWHERE OVER THE GREAT LAKES REGION WITH COPIOUS AMOUNTS OF
RAINFALL ALONG THE TRAILING COLD FRONT. LATEST NAM BUFR SOUNDINGS
ARE ALSO MUCH MORE OMINOUS REGARDING THUNDER POTENTIAL WITH ALMOST
1000 J/KG OF ELEVATED CAPE. THIS IS PROBABLY OVERDONE BUT GIVEN THE
STRENGTH OF THE DEVELOPING LLJ COULD EASILY SEE SOME THUNDER
OCCURRING LATE TUESDAY AND WILL ADD MENTION TO THE FORECAST. GIVEN
THE POTENTIAL FOR CONVECTION COUPLED WITH STRONG WARM/MOIST AIR
ADVECTION AHEAD OF THE FRONT AND EXCELLENT FORCING ALOFT...QPF
AMOUNTS IN EXCESS OF AN INCH ARE POSSIBLE TUESDAY NIGHT. THIS
CERTAINLY RAISES THE CONCERN FOR FLOODING WITH MELTING SNOWPACK IN
THE NORTH AND LIKELY STILL FROZEN GROUND.
ARCTIC AIR RETURNS BY LATE WEDNESDAY WITH THE REESTABLISHMENT OF
NORTHWEST FLOW AND CAA. COLDEST AIR WILL TAKE SOME TIME TO FILTER
INTO THE REGION SO THERE MAY BE A BRIEF LULL IN THE PRECIP BEFORE
THE LAKE EFFECT GETS GOING BUT WILL MAINTAIN HIGH CHANCE POPS ON
WEDNESDAY GIVEN UNCERTAINTY IN EXACT TIMING OF EXITING FRONT. WILL
ALSO LIKELY BE AN ATYPICAL DIURNAL CURVE WITH AFTERNOON TEMPS
FALLING FROM MORNING HIGHS AROUND 40F. LAKE RESPONSE DOESNT TRULY
LIGHT UP UNTIL THURSDAY WITH THE APPROACH OF A VIGOROUS SHORTWAVE
AND 850MB TEMPS BOTTOMING OUT IN THE LOW -20S. LAKE EFFECT SNOW WILL
CONTINUE THROUGH FRIDAY BUT A WNW FETCH WILL LIKELY CONFINE BIGGEST
IMPACTS TO OUR EXTREME NORTHERN COUNTIES. HIGH TEMPS DURING THIS
PERIOD WILL LIKELY STRUGGLE TO GET ABOVE 20F GIVEN AFOREMENTIONED
850MB TEMPS. LOW LEVEL RIDGE AXIS SHIFTS EAST ON FRIDAY BUT ONLY A
BRIEF RESPITE FROM PRECIP CHANCES BEFORE ANOTHER CLIPPER SYSTEM
DIVES ACROSS THE REGION ON SATURDAY.
&&
.AVIATION...
06Z TAFS...BACKING LOW LEVEL FLOW OVERNIGHT WILL ALLOW WARM/MOIST
ADVECTION TO OCCUR THROUGH THE END OF THIS FORECAST PERIOD.
STRONGEST ADVECTION IS EXPECTED DURING THE AFTERNOON/EVENING HOURS
TODAY. THIS ADVECTION COMBINED WITH A FAST MOVING UPPER LEVEL
DISTURBANCE KICKING OUT OF THE SOUTHERN ROCKIES WILL RESULT IN
WIDESPREAD PRECIPITATION DEVELOPMENT OVERSPREADING NORTHERN
INDIANA THIS AFTERNOON AND THIS EVENING. PRECIPITATION TYPES WILL
CONTINUE TO BE TRICKY TO FORECAST...AT LEAST INITIALLY WHEN WET
BULB EFFECTS MAY ALLOW FOR A BRIEF PERIOD OF SNOW OR SLEET BEFORE
THERMAL/MOISTURE PROFILES ARE QUICKLY OVERWHELMED BY THE STRONG
ADVECTION. THIS WILL LIKELY SUPPORT A PERIOD OF FREEZING RAIN IN
THE EVENING. CURRENT INDICATIONS SUGGEST THE BEST CHANCE FOR
FREEZING RAIN IN THE 00Z-04Z TIMEFRAME WITH SIMILAR CHANGEOVER TO
RAIN TIMING CURRENTLY EXPECTED AT BOTH KFWA AND KSBN AFTER 04Z. A
RAPID DETERIORATION IN CIGS TO MVFR EXPECTED THIS EVENING...AND
THEN TO IFR LATER THIS EVENING AS COLUMN CONTINUES TO SATURATE.
LIGHT AND VARIABLE WINDS AT 06Z...SHOULD BECOME SOUTHEAST AND
INCREASE INTO THE 12G20KT RANGE FOR THE AFTERNOON BEFORE VEERING
MORE SOUTHERLY TOWARD THE END OF THE PERIOD AS SFC LOW PRESSURE
TRACKS INTO SOUTHEAST IOWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR INZ006-007-009.
FREEZING RAIN ADVISORY FROM 3 PM EST /2 PM CST/ THIS AFTERNOON
TO MIDNIGHT EST /11 PM CST/ TONIGHT FOR INZ003>005-008-
012>018-020-022>027-032>034.
MI...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR MIZ078>081.
FREEZING RAIN ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
TONIGHT FOR MIZ077.
OH...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 3 AM EST MONDAY
FOR OHZ001-002-004-005-015-016-024-025.
LM...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST MONDAY
FOR LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS DES MOINES IA
335 PM CST SUN JAN 27 2013
.SHORT TERM /TONIGHT/...
UPPER LEVEL FORCING CONTINUES TO WANE WITH DEPARTING KINEMATIC AND
THERMODYNAMIC FORCING AS SHORT WAVE CROSSES SRN MN/WI BORDER.
POCKET OF WEAK INSTABILITY WITH A FEW HUNDRED MUCAPES IS ALSO
EXITING INTO IL. THIS HAD ENDED OUR THREAT OF SHOWERS AND
SUBSTANTIAL PRECIP. HOWEVER WEAK FORCING AND CERTAINLY MOISTURE
LINGERS 2KM AND BELOW AND WILL RESULT IN PERSISTENT DRIZZLE OR
FREEZING DRIZZLE. THIS SENSIBLE WEATHER IS DEPICTED NICELY BY THE
LOW LEVEL RAP 285-295K ISENT LAYER WHICH SHOWS MODERATE MOISTURE
TRANSPORT AND LIFT THROUGH THE EVENING. THIS WILL ALSO KEEP LOW
CLOUDS AND FOG LOCKED IN PLACE. FOG MAY BE DENSE AT TIMES...BUT
CONFIDENCE IN WIDESPREAD 1/4SM OR LESS VSBYS IS NOT GREAT ENOUGH TO
HEADLINE QUITE YET WITH MOISTURE TRANSPORT ENDING LATE AND LITTLE
RADIATIONAL COOLING. ALTHOUGH ONLY TOKEN ADDITIONAL ICE
ACCUMULATIONS ARE ANTICIPATED...HAVE LEFT HEADLINES UNCHANGED
NORTH. LITTLE IMPROVEMENT IS ANTICIPATED THERE WITH TEMPS HOVERING
AROUND 32F ALONG WITH THE DRIZZLE AND FOG. ADVISORY CANCELED
FARTHER SOUTH WHERE TEMPS SHOULD REMAIN ABOVE FREEZING.
.LONG TERM /MONDAY THROUGH SUNDAY/...
FAIRLY ACTIVE MID/LONG RANGE ACROSS THE AREA WITH MAJOR FOCUS ON
MONDAY INTO TUESDAY. LARGE UPPER LEVEL TROUGH THAT HAS BEEN SLOWLY
PROGRESSING THROUGH THE INTERMOUNTAIN WEST...WILL CONTINUE TO
TRANSLATE EASTWARD ACROSS THE CENTRAL PLAINS INTO THE OHIO VALLEY
THROUGH WEDNESDAY. INITIALLY THE STATE WILL REMAIN IN SOUTHWEST FLOW
ALOFT...WITH CONTINUE LOW LEVEL MOISTURE PUMPING NORTHWARD FROM THE
GULF OF MEXICO. SFC LOW PRESSURE DEVELOPING IN LEE OF THE
ROCKIES...BEGINS TO SHIFT EAST AND ELONGATE INTO CENTRAL KS/SC
NEBRASKA TOWARD MONDAY AFTERNOON. AN ASSOCIATED WARM FRONT WILL LIFT
NORTHWARD THROUGH THE STATE LATE MONDAY INTO MONDAY NIGHT. MOISTURE
OVERRUNNING THE AREA TO THE NORTH OF THIS WARM FRONT WILL LEAD TO
LOW STRATUS AND FOG LINGERING ACROSS THE CWA MONDAY. ISENTROPIC LIFT
EVIDENT ON THE 285K TO 290K SURFACES BEGINS TO SHOW UP ACROSS THE
SOUTHERN CWA BY LATE MONDAY MORNING WITH LIFT SPREADING NORTHWARD
INTO THE AFTERNOON HOURS. THIS WILL BRING THE CHANCE FOR DRIZZLE OR
LIGHT RAIN TO MUCH OF THE SOUTHERN HALF OF IOWA BY MONDAY AFTERNOON
IN ADDITION TO THE LOW CLOUDS/FOG. VISIBILITIES EXPECTED TO BE QUITE
LOW WITH THE FOG THROUGHOUT THE MORNING HOURS...WITH SOME
IMPROVEMENT IN THE AFTERNOON. POSSIBILITY OF NEEDING A DENSE FOG
ADVISORY FOR THE MORNING HOURS...BUT WILL NOT ISSUE NOW DUE TO
WINTER HEADLINES ALREADY IN EFFECT FOR SIMPLICITY. GREATER PUSH OF
MOISTURE...WITH DEEPER SATURATION EXPECTED AND CONTINUE WAA INTO
MONDAY NIGHT AS WARM FRONT LIFTS NORTHWARD THROUGH THE STATE. HAVE A
NON-DIURNAL TEMPERATURE TREND MONDAY NIGHT AS AREAS EXPECTED TO WARM
OR REMAIN STEADY BEHIND THE WARM FRONT. FOG COULD CONTINUE TO BE AN
ISSUE INTO MONDAY NIGHT WITH ABUNDANT LOW LEVEL MOISTURE.
ADDITIONALLY NAM/GFS BOTH ADVERTISE SOME ELEVATED INSTABILITY
SPREADING NORTHWARD INTO THE CWA...WITH THE NAM MOST AGGRESSIVE.
THEREFORE CONTINUED THE THUNDER MENTION ACROSS THE SOUTHERN
HALF/EASTERN HALF OF THE CWA.
AS THE SFC LOW LIFTS NORTHEASTWARD THROUGH THE STATE INTO TUESDAY
MORNING...ASSOCIATED COLD FRONT TO PUSH THROUGH CWA TUESDAY. THIS
WILL LEAD TO PRECIPITATION TRANSITIONING TO A MIX OF RAIN/SNOW TO
ALL SNOW/FLURRIES ACROSS THE NORTHERN CWA BEFORE PRECIPITATION
TAPERS OFF LATER THAT DAY. POSSIBILITY STILL EXISTS THAT COULD SEE A
MIX OF FREEZING RAIN AS WELL...AS DEPENDS ON HOW DEEP SATURATION IS
AND IF ICE CAN BE INTRODUCED INTO THE COLUMN. CURRENT NAM SOUNDINGS
SUGGEST DEEP ENOUGH SATURATION WITH ICE INTRODUCED WHICH WOULD ALLOW
FOR SNOW...WHILE GFS SUGGEST DRIER AIR ALOFT WITH NO ICE
INTRODUCTION LEADING TO RAIN/FZRA/FZDZ DEPENDING ON SURFACE TEMPS.
FOR NOW HAVE TRENDED FORECAST TOWARD THE NAM SOLUTION. BROAD UPPER
LEVEL TROUGH THEN REMAINS ACROSS THE EASTERN US...WITH NORTHWESTERLY
FLOW ALOFT FOR THE REMAINDER OF THE PERIOD. THIS WILL ALLOW FOR A
SERIES OF WEAK SHORTWAVES TO TRAVEL THROUGH THE MAIN UPPER LEVEL
TROUGH AND DROP SOUTH THROUGH THE CWA. THIS WILL BRING CONTINUED
PUSHES OF ARCTIC AIR FOR LATE THIS WEEK INTO THE WEEKEND...WITH H85
TEMPS DROPPING INTO THE NEGATIVE TEENS TO 20S CELSIUS. THIS WILL
SEND TEMPERATURES TO BELOW AVERAGE BY THE END OF THE WEEK INTO THE
WEEKEND. WITH EACH WAVE PASSAGE...SOME FLURRIES OR LIGHT SNOW MAY BE
POSSIBLE BUT HAVE LEFT THE FORECAST MAINLY DRY FOR NOW WITH THE
UNCERTAINTY IN THE TIMING OF EACH IMPULSE. BROAD UPPER LEVEL RIDGING
BEGINS TO NUDGE INTO THE CENTRAL US TOWARD THE END OF THE WEEKEND
INTO EARLY NEXT WEEK...SUGGESTING A WARMING TREND AS H85 TEMPS CLIMB
BACK ABOVE FREEZING.
&&
.AVIATION...27/18Z
CONDITIONS HAVE CONTINUED TO DETERIORATE INTO IA NORTH OF WARM FRONT
EXTENDING ACROSS NE AND KS INTO MO AT 17Z. WIDESPREAD LIFR/IFR
CONDITIONS ARE IN PLACE OVER IA AND ARE EXPECTED TO REMAIN THAT WAY
INTO THE NIGHT WITH PERSISTENT DRIZZLE AND/OR FREEZING DRIZZLE
THROUGH AT LEAST THE EVENING. LITTLE IMPROVEMENT IS EXPECTED MON
MORNING EITHER WITH LIGHT WINDS KEEPING LOW LEVEL MOISTURE IN PLACE.
KFOD WIND SENSOR HAS FROZEN WITH FORECAST ESTIMATED.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR EMMET-
HAMILTON-HUMBOLDT-KOSSUTH-MARSHALL-PALO ALTO-POCAHONTAS-
STORY-TAMA-WEBSTER.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BLACK HAWK-
BREMER-BUTLER-CERRO GORDO-FRANKLIN-GRUNDY-HANCOCK-HARDIN-
WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...SMALL
LONG TERM...BEERENDS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1126 AM CST SUN JAN 27 2013
.AVIATION...
CONDITIONS WILL BE...OR SHORTLY BECOME IFR/LIFR BY 20Z...THEN CONTINUE
FOR AT LEAST THE NEXT 24 HOURS WITH PERIODS OF -FZRA BECOMING -RA
OR -DZ AS TEMPERATURE RISE ABOVE FREEZING BETWEEN 18-23Z. WARM
MOIST AIR MOVING UP FROM THE SOUTH WILL KEEP CEILINGS LOW...AOB 1K
AGL AND PROBABLY BELOW 500 FT THIS EVENING AND MONDAY. VISIBILITIES
WILL BE 1-2 MILES THIS AFTERNOON...DECREASING TO MOSTLY AOB 1 MILE
TONIGHT THROUGH MONDAY WITH AIRPORT MINIMUM THRESHOLDS POSSIBLE
LATE TONIGHT AND MOST OF THE MORNING HOURS ON MONDAY.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 400 AM CST SUN JAN 27 2013/
UPDATE...
RADAR TRENDS INDICATE SLEET/FREEZING RAIN HAS MOVED INTO OR WILL
DEVELOP VERY SOON IN THE FAR SOUTHWEST PARTS OF THE CWFA. RECENT
RAP TRENDS CONTINUE TO SHOW A VERY RAPID TOP DOWN SATURATION
OCCURRING THIS MORNING WITH WBZ TEMPERATURES AT THE SFC REMAINING
BELOW FREEZING. TEMPERATURES WILL BE THE KEY AND THE DRY
ATMOSPHERE SHOULD INITIALLY ALLOW TEMPERATURES TO DROP ONCE THE
PRECIPITATION BEGINS. MAX TEMPERATURES TODAY LOOK TO OCCUR CLOSE
TO 6 PM. ..08..
PREV DISCUSSION...
SYNOPSIS...
6Z SFC ANALYSIS HAS LOWS IN SOUTHEAST WYOMING AND EASTERN COLORADO
WITH ASSOCIATED FRONTS CONNECTING THEM. A WEAK LOW WAS NEAR K9V9 IN
SOUTH DAKOTA WITH A WARM FRONT RUNNING ROUGHLY ALONG THE MISSOURI
RIVER INTO CENTRAL MISSOURI. DEW POINTS WERE IN THE SINGLE DIGITS
AND TEENS ACROSS THE GREAT LAKES WITH 20S AND HIGHER IN THE PLAINS
AND LOWER MISSISSIPPI VALLEY.
SHORT TERM...EARLY THIS MORNING AND TODAY...
HEADLINES...HAVE TRANSITIONED TO A FREEZING RAIN ADVISORY FOR MOST
OF THE AREA. AN ICE STORM WARNING HAS BEEN ISSUED FOR THE HWY 20
CORRIDOR FROM DBQ ON WEST. THERE SHOULD BE A QUICK ICE ACCUMULATION
WITHIN THE FIRST COUPLE HOURS ONCE THE FREEZING RAIN BEGINS AT ANY
ONE LOCATION.
BASED ON CURRENT RADAR AND RAP TRENDS...FREEZING RAIN WILL BEGIN
MOVING INTO THE FAR SOUTHWEST/WEST PARTS OF THE CWFA IN THE 10-12Z
TIME FRAME. FCST SOUNDINGS SHOW CONSIDERABLE DRY AIR ACROSS THE AREA
AND WBZ TEMPERATURES AT THE SFC AND 0.5 KM ARE BELOW FREEZING
INITIALLY. THUS TREMENDOUS EVAPORATIVE COOLING WILL OCCUR TO HELP
HOLD TEMPERATURES DOWN AND ALLOW SLEET TO MIX IN WITH THE FREEZING
RAIN.
BASED ON RAP TRENDS...TOP DOWN SATURATION WILL RAPIDLY OCCUR OVER
ALL BUT THE FAR EASTERN PARTS OF THE CWFA BY MID MORNING. WBZ
TEMPERATURES CONTINUE TO REMAIN BELOW FREEZING AT THE SFC AND AT 0.5
KM BUT WBZ TEMPERATURES SLOWLY RISE FROM SOUTHWEST TO NORTHEAST
DURING THE MORNING. THUS FREEZING RAIN WITH SOME SLEET WILL BE SEEN
ACROSS THE ENTIRE AREA DURING THE MORNING.
TREMENDOUS WAA CONTINUES INTO THE AFTERNOON HOURS WHICH WILL ALLOW
THE FREEZING RAIN/SLEET TO CHANGE OVER TO ALL RAIN FROM SOUTHWEST TO
NORTHEAST. HOWEVER...MOST AREAS ALONG/NORTH OF HWY 30 WILL LIKELY
SEE FREEZING RAIN/SLEET CONTINUE THROUGH THE AFTERNOON HOURS.
DUE TO THE TREMENDOUS EVAPORATIVE COOLING THAT WILL OCCUR DURING THE
DAY...TEMPERATURES MAY INITIALLY DROP SEVERAL DEGREES ONCE THE
PRECIPITATION BEGINS. HOWEVER...THE SURGE OF MOISTURE MOVING NORTH
INTO THE AREA WILL BODILY FORCE TEMPERATURES UP AGAIN AS THE DAY
PROGRESSES. ..08..
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT THROUGH TUESDAY WILL BE A VERY ACTIVE PERIOD WITH
CHALLENGING WEATHER THROUGHOUT. SUNDAY EVENING THE DAYTIME STORM
SYSTEM GRADUALLY SHIFTS NORTHEAST. THE UPPER LEVEL SHORTWAVE
SWEEPS NORTHEAST OF THE AREA...BUT THE STRONG WARM AIR ADVECTION
AND MOISTURE ADVECTION CONTINUES AS A WEAK SURFACE LOW RIPPLES UP
FROM KANSAS TO WISCONSIN OVERNIGHT. THE STRONG WARM AIR ADVECTION
WILL CAUSE SURFACE TEMPERATURES TO CONTINUE TO WARM
OVERNIGHT. WHILE TEMPERATURES ACROSS THE HIGHWAY 20 CORRIDOR WILL
BE JUST BELOW FREEZING AS OF 00Z...THEY SHOULD RISE ABOVE FREEZING
AROUND MID EVENING. THIS SHOULD END THE FREEZING RAIN THREAT FOR
THE ENTIRE AREA BY 03Z TONIGHT. THUS...THE ENDING TIME OF THE
NORTHERN MOST PORTIONS OF THE FREEZING RAIN ADVISORY AND ICE STORM
WARNING. AFTERWARDS...A WEAK TROUGH MOVES ACROSS THE AREA
OVERNIGHT. TEMPERATURES SHOULD REMAIN RELATIVELY WARM
OVERNIGHT...ABOVE FREEZING. SO...WHILE I EXPECT SOME LINGERING
LIGHT PRECIPITATION OVERNIGHT IN THE VICINITY OF THIS TROUGH
AXIS...FREEZING RAIN SHOULD NOT BE A CONCERN.
MONDAY AND TUESDAY THIS WEAK SURFACE TROUGH AXIS SAGS TO ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA. AT UPPER LEVELS A LARGE
SCALE TROUGH MOVES ACROSS THE ROCKIES MONDAY...AND OVER THE
MIDWEST ON TUESDAY. THIS UPPER LEVEL TROUGH AND THE SOUTHWEST FLOW
OVER THE MIDWEST AHEAD OF IT...IS EXPECTED TO GENERATE A NEW
SURFACE LOW OVER EASTERN COLORADO...AND SWEEP NORTHEAST ACROSS
IOWA OR WESTERN ILLINOIS ON TUESDAY. THE GFS IS THE FARTHEST WEST
OF THE MODELS...AND RUNS THE SURFACE LOW OVER CENTRAL IOWA...WHILE
THE NAM AND ECMWF ARE FARTHER EAST AND ARE CLOSER TO THE
MISSISSIPPI RIVER. THIS IS GOING TO BRING ANOTHER SURGE OF WARM
AIR INTO THE AREA MONDAY NIGHT AND TUESDAY...WITH HIGHS EXPECTED
IN THE 40S AND 50S ON MONDAY AND TUESDAY...WITH VERY LARGE
GRADIENTS ACROSS THE CWFA. WITH THE SURFACE LOW PASSAGE THERE
SHOULD BE A SURGE OF RAINFALL...LIKELY WITH CONVECTIVE ELEMENTS
EMBEDDED WITHIN IT. HAVE INCLUDED SOME ISOLATED THUNDER FOR
PORTIONS OF THE AREA AS MID LEVEL LAPSE RATES AND THE DYNAMICS MAY
BE ABLE TO SUPPORT SOME RUMBLES OF THUNDER. BEHIND THIS SURFACE
LOW WE FINALLY GET THE COLD FRONT TO SWEEP THROUGH THE
AREA...BRINGING MUCH COLDER AIR TO THE AREA TUESDAY NIGHT. WHILE
I DO NOT EXPECT MUCH PRECIPITATION BEHIND THE COLD FRONT...WHAT IS
THERE SHOULD GRADUALLY CHANGE OVER TO ALL SNOW OVERNIGHT.
BY WEDNESDAY MORNING WE WILL BE BACK INTO THE COLD AIR
AGAIN...WITH HIGHS ON WEDNESDAY IN THE 20S TO LOW 30S. STRONG COLD
AIR ADVECTION THROUGH THE DAY WITH NORTHWEST FLOW BEHIND THE UPPER
LEVEL TROUGH TO BRING A FRESH SURGE OF COLD AIR. THE 500MB COLD
POOL IS PRETTY STEEP...SO WE MAY HAVE SOME INSTABILITY SHOWERS
DURING THE DAY...BUT JUST ENOUGH UNCERTAINTY SO HAVE LEFT OUT FOR
NOW.
THURSDAY THROUGH SATURDAY THE MODELS KEEP US IN STRONG NORTHWEST
FLOW WITH SOME HINTS AT A FAST MOVING SHORTWAVE TO DROP THROUGH AT
SOME POINT. MODELS ARE QUITE DIFFERENT AT THIS TIME...AS CAN BE
EXPECTED WITH SUCH A SMALL SCALE FEATURE. FOR NOW AM CARRYING
SOME SLIGHT CHANCES FOR FRIDAY NIGHT AND SATURDAY...THOUGH WE MAY
ALSO NEED SOME ON THURSDAY NIGHT AS WELL. TEMPERATURES WILL BE
BACK TO COLDER THAN NORMAL VALUES FOR THIS TIME OF YEAR...WITH A
WARM-UP EXPECTED ON SATURDAY TO NEAR NORMAL. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR JACKSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR DES
MOINES-HENRY IA-JEFFERSON-KEOKUK-LEE-VAN BUREN-WASHINGTON.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BENTON-
CEDAR-CLINTON-IOWA-JOHNSON-JONES-LINN-LOUISA-MUSCATINE-
SCOTT.
ICE STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BUCHANAN-
DELAWARE-DUBUQUE.
IL...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR CARROLL-
JO DAVIESS-STEPHENSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR HANCOCK-
HENDERSON-MCDONOUGH-WARREN.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BUREAU-
HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
MO...FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-
SCOTLAND.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
535 AM CST SUN JAN 27 2013
.UPDATE...
RADAR TRENDS INDICATE SLEET/FREEZING RAIN HAS MOVED INTO OR WILL
DEVELOP VERY SOON IN THE FAR SOUTHWEST PARTS OF THE CWFA. RECENT
RAP TRENDS CONTINUE TO SHOW A VERY RAPID TOP DOWN SATURATION
OCCURRING THIS MORNING WITH WBZ TEMPERATURES AT THE SFC REMAINING
BELOW FREEZING. TEMPERATURES WILL BE THE KEY AND THE DRY
ATMOSPHERE SHOULD INITIALLY ALLOW TEMPERATURES TO DROP ONCE THE
PRECIPITATION BEGINS. MAX TEMPERATURES TODAY LOOK TO OCCUR CLOSE
TO 6 PM. ..08..
&&
.AVIATION...
VFR CONDITIONS WILL COLLAPSE TO IFR/LIFR WITH FZRA/PL AS A STORM
SYSTEM MOVES ACROSS THE AREA. SIGNIFICANT ICE ACCUMULATIONS ARE
EXPECTED AT KDBQ AND ARE POSSIBLE AT KCID/KMLI. WARM AIR MOVING UP
FROM THE SOUTH WILL ALLOW THE FZRA/PL TO CHANGE OVER TO RA AT
KBRL/KMLI BEFORE SUNSET AND AFTER SUNSET AT KCID/KDBQ. THE WARM AIR
OVER COLD GROUND WILL RESULT IN FG WITH LIFR CONDITIONS AFT
03Z/28. ..08..
&&
.PREV DISCUSSION... /ISSUED 400 AM CST SUN JAN 27 2013/
SYNOPSIS...
6Z SFC ANALYSIS HAS LOWS IN SOUTHEAST WYOMING AND EASTERN COLORADO
WITH ASSOCIATED FRONTS CONNECTING THEM. A WEAK LOW WAS NEAR K9V9 IN
SOUTH DAKOTA WITH A WARM FRONT RUNNING ROUGHLY ALONG THE MISSOURI
RIVER INTO CENTRAL MISSOURI. DEW POINTS WERE IN THE SINGLE DIGITS
AND TEENS ACROSS THE GREAT LAKES WITH 20S AND HIGHER IN THE PLAINS
AND LOWER MISSISSIPPI VALLEY.
SHORT TERM...EARLY THIS MORNING AND TODAY...
HEADLINES...HAVE TRANSITIONED TO A FREEZING RAIN ADVISORY FOR MOST
OF THE AREA. AN ICE STORM WARNING HAS BEEN ISSUED FOR THE HWY 20
CORRIDOR FROM DBQ ON WEST. THERE SHOULD BE A QUICK ICE ACCUMULATION
WITHIN THE FIRST COUPLE HOURS ONCE THE FREEZING RAIN BEGINS AT ANY
ONE LOCATION.
BASED ON CURRENT RADAR AND RAP TRENDS...FREEZING RAIN WILL BEGIN
MOVING INTO THE FAR SOUTHWEST/WEST PARTS OF THE CWFA IN THE 10-12Z
TIME FRAME. FCST SOUNDINGS SHOW CONSIDERABLE DRY AIR ACROSS THE AREA
AND WBZ TEMPERATURES AT THE SFC AND 0.5 KM ARE BELOW FREEZING
INITIALLY. THUS TREMENDOUS EVAPORATIVE COOLING WILL OCCUR TO HELP
HOLD TEMPERATURES DOWN AND ALLOW SLEET TO MIX IN WITH THE FREEZING
RAIN.
BASED ON RAP TRENDS...TOP DOWN SATURATION WILL RAPIDLY OCCUR OVER
ALL BUT THE FAR EASTERN PARTS OF THE CWFA BY MID MORNING. WBZ
TEMPERATURES CONTINUE TO REMAIN BELOW FREEZING AT THE SFC AND AT 0.5
KM BUT WBZ TEMPERATURES SLOWLY RISE FROM SOUTHWEST TO NORTHEAST
DURING THE MORNING. THUS FREEZING RAIN WITH SOME SLEET WILL BE SEEN
ACROSS THE ENTIRE AREA DURING THE MORNING.
TREMENDOUS WAA CONTINUES INTO THE AFTERNOON HOURS WHICH WILL ALLOW
THE FREEZING RAIN/SLEET TO CHANGE OVER TO ALL RAIN FROM SOUTHWEST TO
NORTHEAST. HOWEVER...MOST AREAS ALONG/NORTH OF HWY 30 WILL LIKELY
SEE FREEZING RAIN/SLEET CONTINUE THROUGH THE AFTERNOON HOURS.
DUE TO THE TREMENDOUS EVAPORATIVE COOLING THAT WILL OCCUR DURING THE
DAY...TEMPERATURES MAY INITIALLY DROP SEVERAL DEGREES ONCE THE
PRECIPITATION BEGINS. HOWEVER...THE SURGE OF MOISTURE MOVING NORTH
INTO THE AREA WILL BODILY FORCE TEMPERATURES UP AGAIN AS THE DAY
PROGRESSES. ..08..
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT THROUGH TUESDAY WILL BE A VERY ACTIVE PERIOD WITH
CHALLENGING WEATHER THROUGHOUT. SUNDAY EVENING THE DAYTIME STORM
SYSTEM GRADUALLY SHIFTS NORTHEAST. THE UPPER LEVEL SHORTWAVE
SWEEPS NORTHEAST OF THE AREA...BUT THE STRONG WARM AIR ADVECTION
AND MOISTURE ADVECTION CONTINUES AS A WEAK SURFACE LOW RIPPLES UP
FROM KANSAS TO WISCONSIN OVERNIGHT. THE STRONG WARM AIR ADVECTION
WILL CAUSE SURFACE TEMPERATURES TO CONTINUE TO WARM
OVERNIGHT. WHILE TEMPERATURES ACROSS THE HIGHWAY 20 CORRIDOR WILL
BE JUST BELOW FREEZING AS OF 00Z...THEY SHOULD RISE ABOVE FREEZING
AROUND MID EVENING. THIS SHOULD END THE FREEZING RAIN THREAT FOR
THE ENTIRE AREA BY 03Z TONIGHT. THUS...THE ENDING TIME OF THE
NORTHERN MOST PORTIONS OF THE FREEZING RAIN ADVISORY AND ICE STORM
WARNING. AFTERWARDS...A WEAK TROUGH MOVES ACROSS THE AREA
OVERNIGHT. TEMPERATURES SHOULD REMAIN RELATIVELY WARM
OVERNIGHT...ABOVE FREEZING. SO...WHILE I EXPECT SOME LINGERING
LIGHT PRECIPITATION OVERNIGHT IN THE VICINITY OF THIS TROUGH
AXIS...FREEZING RAIN SHOULD NOT BE A CONCERN.
MONDAY AND TUESDAY THIS WEAK SURFACE TROUGH AXIS SAGS TO ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA. AT UPPER LEVELS A LARGE
SCALE TROUGH MOVES ACROSS THE ROCKIES MONDAY...AND OVER THE
MIDWEST ON TUESDAY. THIS UPPER LEVEL TROUGH AND THE SOUTHWEST FLOW
OVER THE MIDWEST AHEAD OF IT...IS EXPECTED TO GENERATE A NEW
SURFACE LOW OVER EASTERN COLORADO...AND SWEEP NORTHEAST ACROSS
IOWA OR WESTERN ILLINOIS ON TUESDAY. THE GFS IS THE FARTHEST WEST
OF THE MODELS...AND RUNS THE SURFACE LOW OVER CENTRAL IOWA...WHILE
THE NAM AND ECMWF ARE FARTHER EAST AND ARE CLOSER TO THE
MISSISSIPPI RIVER. THIS IS GOING TO BRING ANOTHER SURGE OF WARM
AIR INTO THE AREA MONDAY NIGHT AND TUESDAY...WITH HIGHS EXPECTED
IN THE 40S AND 50S ON MONDAY AND TUESDAY...WITH VERY LARGE
GRADIENTS ACROSS THE CWFA. WITH THE SURFACE LOW PASSAGE THERE
SHOULD BE A SURGE OF RAINFALL...LIKELY WITH CONVECTIVE ELEMENTS
EMBEDDED WITHIN IT. HAVE INCLUDED SOME ISOLATED THUNDER FOR
PORTIONS OF THE AREA AS MID LEVEL LAPSE RATES AND THE DYNAMICS MAY
BE ABLE TO SUPPORT SOME RUMBLES OF THUNDER. BEHIND THIS SURFACE
LOW WE FINALLY GET THE COLD FRONT TO SWEEP THROUGH THE
AREA...BRINGING MUCH COLDER AIR TO THE AREA TUESDAY NIGHT. WHILE
I DO NOT EXPECT MUCH PRECIPITATION BEHIND THE COLD FRONT...WHAT IS
THERE SHOULD GRADUALLY CHANGE OVER TO ALL SNOW OVERNIGHT.
BY WEDNESDAY MORNING WE WILL BE BACK INTO THE COLD AIR
AGAIN...WITH HIGHS ON WEDNESDAY IN THE 20S TO LOW 30S. STRONG COLD
AIR ADVECTION THROUGH THE DAY WITH NORTHWEST FLOW BEHIND THE UPPER
LEVEL TROUGH TO BRING A FRESH SURGE OF COLD AIR. THE 500MB COLD
POOL IS PRETTY STEEP...SO WE MAY HAVE SOME INSTABILITY SHOWERS
DURING THE DAY...BUT JUST ENOUGH UNCERTAINTY SO HAVE LEFT OUT FOR
NOW.
THURSDAY THROUGH SATURDAY THE MODELS KEEP US IN STRONG NORTHWEST
FLOW WITH SOME HINTS AT A FAST MOVING SHORTWAVE TO DROP THROUGH AT
SOME POINT. MODELS ARE QUITE DIFFERENT AT THIS TIME...AS CAN BE
EXPECTED WITH SUCH A SMALL SCALE FEATURE. FOR NOW AM CARRYING
SOME SLIGHT CHANCES FOR FRIDAY NIGHT AND SATURDAY...THOUGH WE MAY
ALSO NEED SOME ON THURSDAY NIGHT AS WELL. TEMPERATURES WILL BE
BACK TO COLDER THAN NORMAL VALUES FOR THIS TIME OF YEAR...WITH A
WARM-UP EXPECTED ON SATURDAY TO NEAR NORMAL. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR JACKSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR DES
MOINES-HENRY IA-JEFFERSON-KEOKUK-LEE-VAN BUREN-WASHINGTON.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BENTON-
CEDAR-CLINTON-IOWA-JOHNSON-JONES-LINN-LOUISA-MUSCATINE-
SCOTT.
ICE STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BUCHANAN-
DELAWARE-DUBUQUE.
IL...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR CARROLL-
JO DAVIESS-STEPHENSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR HANCOCK-
HENDERSON-MCDONOUGH-WARREN.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BUREAU-
HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
MO...FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
400 AM CST SUN JAN 27 2013
.SYNOPSIS...
6Z SFC ANALYSIS HAS LOWS IN SOUTHEAST WYOMING AND EASTERN COLORADO
WITH ASSOCIATED FRONTS CONNECTING THEM. A WEAK LOW WAS NEAR K9V9 IN
SOUTH DAKOTA WITH A WARM FRONT RUNNING ROUGHLY ALONG THE MISSOURI
RIVER INTO CENTRAL MISSOURI. DEW POINTS WERE IN THE SINGLE DIGITS
AND TEENS ACROSS THE GREAT LAKES WITH 20S AND HIGHER IN THE PLAINS
AND LOWER MISSISSIPPI VALLEY.
&&
.SHORT TERM...EARLY THIS MORNING AND TODAY...
HEADLINES...HAVE TRANSITIONED TO A FREEZING RAIN ADVISORY FOR MOST
OF THE AREA. AN ICE STORM WARNING HAS BEEN ISSUED FOR THE HWY 20
CORRIDOR FROM DBQ ON WEST. THERE SHOULD BE A QUICK ICE ACCUMULATION
WITHIN THE FIRST COUPLE HOURS ONCE THE FREEZING RAIN BEGINS AT ANY
ONE LOCATION.
BASED ON CURRENT RADAR AND RAP TRENDS...FREEZING RAIN WILL BEGIN
MOVING INTO THE FAR SOUTHWEST/WEST PARTS OF THE CWFA IN THE 10-12Z
TIME FRAME. FCST SOUNDINGS SHOW CONSIDERABLE DRY AIR ACROSS THE AREA
AND WBZ TEMPERATURES AT THE SFC AND 0.5 KM ARE BELOW FREEZING
INITIALLY. THUS TREMENDOUS EVAPORATIVE COOLING WILL OCCUR TO HELP
HOLD TEMPERATURES DOWN AND ALLOW SLEET TO MIX IN WITH THE FREEZING
RAIN.
BASED ON RAP TRENDS...TOP DOWN SATURATION WILL RAPIDLY OCCUR OVER
ALL BUT THE FAR EASTERN PARTS OF THE CWFA BY MID MORNING. WBZ
TEMPERATURES CONTINUE TO REMAIN BELOW FREEZING AT THE SFC AND AT 0.5
KM BUT WBZ TEMPERATURES SLOWLY RISE FROM SOUTHWEST TO NORTHEAST
DURING THE MORNING. THUS FREEZING RAIN WITH SOME SLEET WILL BE SEEN
ACROSS THE ENTIRE AREA DURING THE MORNING.
TREMENDOUS WAA CONTINUES INTO THE AFTERNOON HOURS WHICH WILL ALLOW
THE FREEZING RAIN/SLEET TO CHANGE OVER TO ALL RAIN FROM SOUTHWEST TO
NORTHEAST. HOWEVER...MOST AREAS ALONG/NORTH OF HWY 30 WILL LIKELY
SEE FREEZING RAIN/SLEET CONTINUE THROUGH THE AFTERNOON HOURS.
DUE TO THE TREMENDOUS EVAPORATIVE COOLING THAT WILL OCCUR DURING THE
DAY...TEMPERATURES MAY INITIALLY DROP SEVERAL DEGREES ONCE THE
PRECIPITATION BEGINS. HOWEVER...THE SURGE OF MOISTURE MOVING NORTH
INTO THE AREA WILL BODILY FORCE TEMPERATURES UP AGAIN AS THE DAY
PROGRESSES. ..08..
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT THROUGH TUESDAY WILL BE A VERY ACTIVE PERIOD WITH
CHALLENGING WEATHER THROUGHOUT. SUNDAY EVENING THE DAYTIME STORM
SYSTEM GRADUALLY SHIFTS NORTHEAST. THE UPPER LEVEL SHORTWAVE
SWEEPS NORTHEAST OF THE AREA...BUT THE STRONG WARM AIR ADVECTION
AND MOISTURE ADVECTION CONTINUES AS A WEAK SURFACE LOW RIPPLES UP
FROM KANSAS TO WISCONSIN OVERNIGHT. THE STRONG WARM AIR ADVECTION
WILL CAUSE SURFACE TEMPERATURES TO CONTINUE TO WARM
OVERNIGHT. WHILE TEMPERATURES ACROSS THE HIGHWAY 20 CORRIDOR WILL
BE JUST BELOW FREEZING AS OF 00Z...THEY SHOULD RISE ABOVE FREEZING
AROUND MID EVENING. THIS SHOULD END THE FREEZING RAIN THREAT FOR
THE ENTIRE AREA BY 03Z TONIGHT. THUS...THE ENDING TIME OF THE
NORTHERN MOST PORTIONS OF THE FREEZING RAIN ADVISORY AND ICE STORM
WARNING. AFTERWARDS...A WEAK TROUGH MOVES ACROSS THE AREA
OVERNIGHT. TEMPERATURES SHOULD REMAIN RELATIVELY WARM
OVERNIGHT...ABOVE FREEZING. SO...WHILE I EXPECT SOME LINGERING
LIGHT PRECIPITATION OVERNIGHT IN THE VICINITY OF THIS TROUGH
AXIS...FREEZING RAIN SHOULD NOT BE A CONCERN.
MONDAY AND TUESDAY THIS WEAK SURFACE TROUGH AXIS SAGS TO ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA. AT UPPER LEVELS A LARGE
SCALE TROUGH MOVES ACROSS THE ROCKIES MONDAY...AND OVER THE
MIDWEST ON TUESDAY. THIS UPPER LEVEL TROUGH AND THE SOUTHWEST FLOW
OVER THE MIDWEST AHEAD OF IT...IS EXPECTED TO GENERATE A NEW
SURFACE LOW OVER EASTERN COLORADO...AND SWEEP NORTHEAST ACROSS
IOWA OR WESTERN ILLINOIS ON TUESDAY. THE GFS IS THE FARTHEST WEST
OF THE MODELS...AND RUNS THE SURFACE LOW OVER CENTRAL IOWA...WHILE
THE NAM AND ECMWF ARE FARTHER EAST AND ARE CLOSER TO THE
MISSISSIPPI RIVER. THIS IS GOING TO BRING ANOTHER SURGE OF WARM
AIR INTO THE AREA MONDAY NIGHT AND TUESDAY...WITH HIGHS EXPECTED
IN THE 40S AND 50S ON MONDAY AND TUESDAY...WITH VERY LARGE
GRADIENTS ACROSS THE CWFA. WITH THE SURFACE LOW PASSAGE THERE
SHOULD BE A SURGE OF RAINFALL...LIKELY WITH CONVECTIVE ELEMENTS
EMBEDDED WITHIN IT. HAVE INCLUDED SOME ISOLATED THUNDER FOR
PORTIONS OF THE AREA AS MID LEVEL LAPSE RATES AND THE DYNAMICS MAY
BE ABLE TO SUPPORT SOME RUMBLES OF THUNDER. BEHIND THIS SURFACE
LOW WE FINALLY GET THE COLD FRONT TO SWEEP THROUGH THE
AREA...BRINGING MUCH COLDER AIR TO THE AREA TUESDAY NIGHT. WHILE
I DO NOT EXPECT MUCH PRECIPITATION BEHIND THE COLD FRONT...WHAT IS
THERE SHOULD GRADUALLY CHANGE OVER TO ALL SNOW OVERNIGHT.
BY WEDNESDAY MORNING WE WILL BE BACK INTO THE COLD AIR
AGAIN...WITH HIGHS ON WEDNESDAY IN THE 20S TO LOW 30S. STRONG COLD
AIR ADVECTION THROUGH THE DAY WITH NORTHWEST FLOW BEHIND THE UPPER
LEVEL TROUGH TO BRING A FRESH SURGE OF COLD AIR. THE 500MB COLD
POOL IS PRETTY STEEP...SO WE MAY HAVE SOME INSTABILITY SHOWERS
DURING THE DAY...BUT JUST ENOUGH UNCERTAINTY SO HAVE LEFT OUT FOR
NOW.
THURSDAY THROUGH SATURDAY THE MODELS KEEP US IN STRONG NORTHWEST
FLOW WITH SOME HINTS AT A FAST MOVING SHORTWAVE TO DROP THROUGH AT
SOME POINT. MODELS ARE QUITE DIFFERENT AT THIS TIME...AS CAN BE
EXPECTED WITH SUCH A SMALL SCALE FEATURE. FOR NOW AM CARRYING
SOME SLIGHT CHANCES FOR FRIDAY NIGHT AND SATURDAY...THOUGH WE MAY
ALSO NEED SOME ON THURSDAY NIGHT AS WELL. TEMPERATURES WILL BE
BACK TO COLDER THAN NORMAL VALUES FOR THIS TIME OF YEAR...WITH A
WARM-UP EXPECTED ON SATURDAY TO NEAR NORMAL. LE
&&
.AVIATION.../ISSUED 1137 PM CST SAT JAN 26 2013/
VFR CONDITIONS WILL BE OVER THE AREA THROUGH 12Z SUNDAY.
CONDITIONS WILL RAPIDLY DETERIORATE DURING THE MORNING AS AN AREA
OF FREEZING RAIN SPREADS NORTHEAST ACROSS THE AREA. IFR CONDITIONS
ARE EXPECTED OVER THE ENTIRE AREA BY MID AFTERNOON. THE FREEZING
RAIN SHOULD CHANGE TO RAIN ALONG AND SOUTH OF HIGHWAY 34 IN
SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS DURING THE MORNING BUT IS
EXPECTED TO CONTINUE NORTH OF THIS AREA THROUGH MUCH IF NOT ALL OF
THE AFTERNOON. IFR TO LOW IFR CONDITIONS WILL REMAIN OVER THE AREA
THROUGH THE EVENING. THERE MAY BE SOME POCKETS OF FREEZING RAIN OR
FREEZING DRIZZLE IN THE FAR NORTH INCLUDING KDBQ
HOWEVER...TEMPERATURES SHOULD BE ABOVE FREEZING IN MOST AREAS
ENDING ANY WIDESPREAD FREEZING PRECIPITATION THREAT.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR JACKSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR DES
MOINES-HENRY IA-JEFFERSON-KEOKUK-LEE-VAN BUREN-WASHINGTON.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BENTON-
CEDAR-CLINTON-IOWA-JOHNSON-JONES-LINN-LOUISA-MUSCATINE-
SCOTT.
ICE STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BUCHANAN-
DELAWARE-DUBUQUE.
IL...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR CARROLL-
JO DAVIESS-STEPHENSON.
FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR HANCOCK-
HENDERSON-MCDONOUGH-WARREN.
FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS EVENING FOR BUREAU-
HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
MO...FREEZING RAIN ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-
SCOTLAND.
&&
$$
LE/08
AREA FORECAST DISCUSSION
NWS GOODLAND KS
105 PM MST SUN JAN 27 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY EVENING)
ISSUED AT 1258 PM MST SUN JAN 27 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW POSITIVELY TILTED TROUGH
EXTENDING FROM BRITISH COLUMBIA TO CENTRAL CALIFORNIA...WITH SW FLOW
ACROSS THE INTER-MOUNTAIN WEST AND CENTRAL PLAINS. SUBSIDENCE IS IN
PLACE OVER CENTRAL KS AND CENTRAL CO WITH SEVERAL WEAK SHORTWAVES
OVER THE NORTHERN PLAINS. A SURFACE TROUGH IS IN PLACE OVER THE
CWA WITH A STALLED WARM FRONT JUST NORTHEAST OF THE CWA IN CENTRAL
NEBRASKA.
AREAS OF FOG/STRATUS MAY REDEVELOP OVERNIGHT TONIGHT PRIMARILY
ALONG THE STATIONARY FRONT IN NEBRASKA...AND THEN SPREAD SW INTO OUR
CWA. MOST GUIDANCE IS KEEPING FOG TO THE NORTH AND EAST OF THE
CWA...HOWEVER LATEST 24HR RUC IS SHOWING FOG/STRATUS OVERSPREADING
THE NE HALF OF CWA. WITH HIGHER TD VALUES POSSIBLY LINGERING ACROSS
THE NE HALF OF THE CWA AND LOW LEVELS DECOUPLING...THE RUC SOLUTION
SEEMS REASONABLE. ACROSS THE WEST AND SOUTH THE BL SHOULD BEGIN TO
DRY OUT OVERNIGHT WITH S/SW FLOW...SO FOG POTENTIAL SHOULD BE
MINIMAL CLOSER TO THE KS/CO STATE LINE.
AS UPPER LEVEL TROUGH IN THE WEST SHIFTS WEST AND ASSOCIATED COLD
FRONT PUSHES SOUTHEAST MONDAY...LEE TROUGH WILL STRENGTHEN WITH
STRONG WAA AND BREEZY CONDITIONS ACROSS THE CWA. HIGH TEMP FORECAST
IS COMPLICATED BY THE POSSIBILITY OF LINGERING STRATUS...AND
INCREASING CLOUDS AS COLD FRONT AND UPPER TROUGH APPROACH CWA LATER
IN THE AFTERNOON. WE COULD ALSO START TO SEE RAIN CHANCES INCREASE
LATE IN THE AFTERNOON ACROSS THE NORTH/NORTHWEST. FOR NOW I KEPT
HIGH TEMPS IN LINE WITH PREVIOUS FORECAST...WITH NEAR RECORD HIGHS
IN THE MID TO UPPER 60S ACROSS NW KANSAS...AND SLIGHTLY COOLER TEMPS
ACROSS THE NORTH.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 1258 PM MST SUN JAN 27 2013
LONGWAVE TROUGH WILL BRING A CHANCE OF LIGHT SNOW TO MOST OF THE
AREA MONDAY NIGHT. BEST CHANCES WILL BE BEFORE MIDNIGHT...THEN
GRADUALLY WINDING DOWN THROUGH TUESDAY MORNING. TOTAL SNOW AMOUNTS
STILL ON TRACK TO BE AN INCH OR LESS...HIGHEST IN COLORADO.
NORTHWEST FLOW ALOFT WILL BE IN PLACE THE REMAINDER OF THE PERIOD.
VERY WEAK SYSTEM MAY BRING FLURRIES OR A LIGHT DUSTING WEDNESDAY
NIGHT AND THURSDAY...OTHERWISE IT WILL BE DRY. TEMPERATURES WILL
BE NEAR TO SLIGHTLY BELOW NORMAL EARLY IN THE PERIOD...BUT WARM TO
AROUND 10 DEGREES ABOVE NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1026 AM MST SUN JAN 27 2013
WITH WINDS EXPECTED TO BE 12KT OR LESS THROUGH THE PERIOD AT BOTH
TERMINALS THE PRIMARY AVIATION FOCUS WILL BE ON CIG/VIS EARLY THIS
AFTERNOON AND AGAIN EARLY MONDAY MORNING. CIG/VIS ALREADY VFR AT
KGLD WITH ANOTHER AREA OF STRATUS OVER EASTERN COLORADO CURRENTLY
EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS BEFORE HAVING A
CHANCE TO IMPACT THE TERMINAL. VIS HAVE IMPROVED AT KMCK AND VFR
VIS SHOULD BE EXPECTED BY 19Z. CIGS HAVE BEEN SLOWER TO IMPROVE AT
KMCK WITH STRATUS LIKELY LINGERING THROUGH MID AFTERNOON BEFORE
VFR CONDITIONS PREVAIL.
AREAS OF STRATUS/FOG WILL REDEVELOP LATE TONIGHT OVER SW NEBRASKA
AND NORTH CENTRAL KANSAS WHERE GOOD MOISTURE POOLING ALONG/NORTH
OF STALLED WARM FRONT IS EXPECTED. I AM NOT CONFIDENT THAT THIS
WILL AFFECT KGLD WITH SW FLOW BRINGING DRIER BL CONDITIONS. KMCK
IS MOST LIKELY TO SEE REDUCED VIS/CIGS WITH LIFR CONDITIONS
DEVELOPING BY 11Z AND IMPROVING BEFORE 16Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1259 PM MST SUN JAN 27 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 1258 PM MST SUN JAN 27 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW POSITIVELY TILTED TROUGH
EXTENDING FROM BRITISH COLUMBIA TO CENTRAL CALIFORNIA...WITH SW FLOW
ACROSS THE INTER-MOUNTAIN WEST AND CENTRAL PLAINS. SUBSIDENCE IS IN
PLACE OVER CENTRAL KS AND CENTRAL CO WITH SEVERAL WEAK SHORTWAVES
OVER THE NORTHERN PLAINS. A SURFACE TROUGH IS IN PLACE OVER THE
CWA WITH A STALLED WARM FRONT JUST NORTHEAST OF THE CWA IN CENTRAL
NEBRASKA.
AREAS OF FOG/STRATUS MAY REDEVELOP OVERNIGHT TONIGHT PRIMARILY
ALONG THE STATIONARY FRONT IN NEBRASKA...AND THEN SPREAD SW INTO OUR
CWA. MOST GUIDANCE IS KEEPING FOG TO THE NORTH AND EAST OF THE
CWA...HOWEVER LATEST 24HR RUC IS SHOWING FOG/STRATUS OVERSPREADING
THE NE HALF OF CWA. WITH HIGHER TD VALUES POSSIBLY LINGERING ACROSS
THE NE HALF OF THE CWA AND LOW LEVELS DECOUPLING...THE RUC SOLUTION
SEEMS REASONABLE. ACROSS THE WEST AND SOUTH THE BL SHOULD BEGIN TO
DRY OUT OVERNIGHT WITH S/SW FLOW...SO FOG POTENTIAL SHOULD BE
MINIMAL CLOSER TO THE KS/CO STATE LINE.
AS UPPER LEVEL TROUGH IN THE WEST SHIFTS WEST AND ASSOCIATED COLD
FRONT PUSHES SOUTHEAST MONDAY...LEE TROUGH WILL STRENGTHEN WITH
STRONG WAA AND BREEZY CONDITIONS ACROSS THE CWA. HIGH TEMP FORECAST
IS COMPLICATED BY THE POSSIBILITY OF LINGERING STRATUS...AND
INCREASING CLOUDS AS COLD FRONT AND UPPER TROUGH APPROACH CWA LATER
IN THE AFTERNOON. WE COULD ALSO START TO SEE RAIN CHANCES INCREASE
LATE IN THE AFTERNOON ACROSS THE NORTH/NORTHWEST. FOR NOW I KEPT
HIGH TEMPS IN LINE WITH PREVIOUS FORECAST...WITH NEAR RECORD HIGHS
IN THE MID TO UPPER 60S ACROSS NW KANSAS...AND SLIGHTLY COOLER TEMPS
ACROSS THE NORTH.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1026 AM MST SUN JAN 27 2013
WITH WINDS EXPECTED TO BE 12KT OR LESS THROUGH THE PERIOD AT BOTH
TERMINALS THE PRIMARY AVIATION FOCUS WILL BE ON CIG/VIS EARLY THIS
AFTERNOON AND AGAIN EARLY MONDAY MORNING. CIG/VIS ALREADY VFR AT
KGLD WITH ANOTHER AREA OF STRATUS OVER EASTERN COLORADO CURRENTLY
EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS BEFORE HAVING A
CHANCE TO IMPACT THE TERMINAL. VIS HAVE IMPROVED AT KMCK AND VFR
VIS SHOULD BE EXPECTED BY 19Z. CIGS HAVE BEEN SLOWER TO IMPROVE AT
KMCK WITH STRATUS LIKELY LINGERING THROUGH MID AFTERNOON BEFORE
VFR CONDITIONS PREVAIL.
AREAS OF STRATUS/FOG WILL REDEVELOP LATE TONIGHT OVER SW NEBRASKA
AND NORTH CENTRAL KANSAS WHERE GOOD MOISTURE POOLING ALONG/NORTH
OF STALLED WARM FRONT IS EXPECTED. I AM NOT CONFIDENT THAT THIS
WILL AFFECT KGLD WITH SW FLOW BRINGING DRIER BL CONDITIONS. KMCK
IS MOST LIKELY TO SEE REDUCED VIS/CIGS WITH LIFR CONDITIONS
DEVELOPING BY 11Z AND IMPROVING BEFORE 16Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1112 AM MST SUN JAN 27 2013
.UPDATE...
ISSUED AT 1112 AM MST SUN JAN 27 2013
I ALLOWED THE DENSE FOG ADVISORY TO EXPIRE WITH VISIBILITIES
IMPROVED ACROSS THE AREA. AREAS OF STRATUS CONTINUE TO LINGER
OVER PARTS OF THE AREA. IF STRATUS HOLDS WE COULD SEE HIGH TEMPS
MUCH COOLER THAN ONGOING FORECAST BY 10-15F WHERE CLOUDS LINGER.
SHORT RANGE GUIDANCE STILL INDICATES STRATUS CLEARING OVER THE
NEXT FEW HOURS...WHICH SHOULD LEAVE ENOUGH TIME DURING PEAK
HEATING TO REALIZE CURRENT FORECAST HIGHS. I ADJUSTED SKY COVER
FORECAST...AND WILL HOLD OFF ON ADJUSTING TEMPS UNTIL I GET A
BETTER HANDLE ON WHAT STRATUS WILL BE DOING OVER THE NEXT FEW
HOURS.
UPDATE ISSUED AT 844 AM MST SUN JAN 27 2013
CANCELLED ADVISORY FOR SHERMAN AND YUMA COUNTIES AND EXTENDED
REMAINING ADVISORY THROUGH 18Z. BASED ON CURRENT TRENDS AND SHORT
RANGE GUIDANCE I EXPECT DENSE FOG TO LINGER LONGER ACROSS MY
NORTHEAST CWA. HRRR WHICH HAS BEST HAND ON CURRENT CONDITIONS
SHOWS FOG DISSIPATING AROUND 18Z IN THE FAR NORTHEAST. THE
WEST/SOUTHWEST EDGE OF FOG/STRATUS IS QUICKLY ERODING AND
CONDITIONS HAVE IMPROVED. FURTHER IMPROVEMENT WILL BE EXPECTED FROM
THE WEST TO THE EAST THROUGH THE REST OF THE MORNING.
UPDATE ISSUED AT 702 AM MST SUN JAN 27 2013
HILL CITY AND WRAY HAVE BOTH REPORTED VISIBILITIES OF 1/4 MILE OR
LESS SO HAVE ADDED THEM TO THE ADVISORY.
UPDATE ISSUED AT 514 AM MST SUN JAN 27 2013
JUST ISSUED A DENSE FOG ADVISORY. AREAS OF DENSE FOG HAVE BECOME
MORE WIDESPREAD OVER MOST OF EXTREME SOUTHWEST NEBRASKA AND THE
FAR NORTH AND NORTHWEST PORTIONS OF NORTHWEST KANSAS. THESE
CONDITIONS HAVE PERSISTED AND GOT WORSE. EVEN DESPITE OF DOWNSLOPE
WINDS...ALBEIT LIGHT...THE DENSE FOG HAS CONTINUE. SMALL SCALE
MODEL OUTPUT HAVING A DIFFICULT TIME GETTING A HANDLE ON THIS. RUC
STARTED OUT WELL BUT IS NOW FADING. HRRR HAS BECOME MUCH BETTER IN
DEPICTING THIS. SO IN ADDITION THE LOCATIONS ALREADY EXPERIENCING
DENSE FOG...ALSO PUT THE ADVISORY INTO RED WILLOW AND NORTON
COUNTIES PER OBSERVATIONAL TRENDS AND BEST MODEL OUTPUT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1026 AM MST SUN JAN 27 2013
WITH WINDS EXPECTED TO BE 12KT OR LESS THROUGH THE PERIOD AT BOTH
TERMINALS THE PRIMARY AVIATION FOCUS WILL BE ON CIG/VIS EARLY THIS
AFTERNOON AND AGAIN EARLY MONDAY MORNING. CIG/VIS ALREADY VFR AT
KGLD WITH ANOTHER AREA OF STRATUS OVER EASTERN COLORADO CURRENTLY
EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS BEFORE HAVING A
CHANCE TO IMPACT THE TERMINAL. VIS HAVE IMPROVED AT KMCK AND VFR
VIS SHOULD BE EXPECTED BY 19Z. CIGS HAVE BEEN SLOWER TO IMPROVE AT
KMCK WITH STRATUS LIKELY LINGERING THROUGH MID AFTERNOON BEFORE
VFR CONDITIONS PREVAIL.
AREAS OF STRATUS/FOG WILL REDEVELOP LATE TONIGHT OVER SW NEBRASKA
AND NORTH CENTRAL KANSAS WHERE GOOD MOISTURE POOLING ALONG/NORTH
OF STALLED WARM FRONT IS EXPECTED. I AM NOT CONFIDENT THAT THIS
WILL AFFECT KGLD WITH SW FLOW BRINGING DRIER BL CONDITIONS. KMCK
IS MOST LIKELY TO SEE REDUCED VIS/CIGS WITH LIFR CONDITIONS
DEVELOPING BY 11Z AND IMPROVING BEFORE 16Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1026 AM MST SUN JAN 27 2013
.UPDATE...
ISSUED AT 844 AM MST SUN JAN 27 2013
CANCELLED ADVISORY FOR SHERMAN AND YUMA COUNTIES AND EXTENDED
REMAINING ADVISORY THROUGH 18Z. BASED ON CURRENT TRENDS AND SHORT
RANGE GUIDANCE I EXPECT DENSE FOG TO LINGER LONGER ACROSS MY
NORTHEAST CWA. HRRR WHICH HAS BEST HAND ON CURRENT CONDITIONS
SHOWS FOG DISSIPATING AROUND 18Z IN THE FAR NORTHEAST. THE
WEST/SOUTHWEST EDGE OF FOG/STRATUS IS QUICKLY ERODING AND
CONDITIONS HAVE IMPROVED. FURTHER IMPROVEMENT WILL BE EXPECTED FROM
THE WEST TO THE EAST THROUGH THE REST OF THE MORNING.
UPDATE ISSUED AT 702 AM MST SUN JAN 27 2013
HILL CITY AND WRAY HAVE BOTH REPORTED VISIBILITIES OF 1/4 MILE OR
LESS SO HAVE ADDED THEM TO THE ADVISORY.
UPDATE ISSUED AT 514 AM MST SUN JAN 27 2013
JUST ISSUED A DENSE FOG ADVISORY. AREAS OF DENSE FOG HAVE BECOME
MORE WIDESPREAD OVER MOST OF EXTREME SOUTHWEST NEBRASKA AND THE
FAR NORTH AND NORTHWEST PORTIONS OF NORTHWEST KANSAS. THESE
CONDITIONS HAVE PERSISTED AND GOT WORSE. EVEN DESPITE OF DOWNSLOPE
WINDS...ALBEIT LIGHT...THE DENSE FOG HAS CONTINUE. SMALL SCALE
MODEL OUTPUT HAVING A DIFFICULT TIME GETTING A HANDLE ON THIS. RUC
STARTED OUT WELL BUT IS NOW FADING. HRRR HAS BECOME MUCH BETTER IN
DEPICTING THIS. SO IN ADDITION THE LOCATIONS ALREADY EXPERIENCING
DENSE FOG...ALSO PUT THE ADVISORY INTO RED WILLOW AND NORTON
COUNTIES PER OBSERVATIONAL TRENDS AND BEST MODEL OUTPUT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1026 AM MST SUN JAN 27 2013
WITH WINDS EXPECTED TO BE 12KT OR LESS THROUGH THE PERIOD AT BOTH
TERMINALS THE PRIMARY AVIATION FOCUS WILL BE ON CIG/VIS EARLY THIS
AFTERNOON AND AGAIN EARLY MONDAY MORNING. CIG/VIS ALREADY VFR AT
KGLD WITH ANOTHER AREA OF STRATUS OVER EASTERN COLORADO CURRENTLY
EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS BEFORE HAVING A
CHANCE TO IMPACT THE TERMINAL. VIS HAVE IMPROVED AT KMCK AND VFR
VIS SHOULD BE EXPECTED BY 19Z. CIGS HAVE BEEN SLOWER TO IMPROVE AT
KMCK WITH STRATUS LIKELY LINGERING THROUGH MID AFTERNOON BEFORE
VFR CONDITIONS PREVAIL.
AREAS OF STRATUS/FOG WILL REDEVELOP LATE TONIGHT OVER SW NEBRASKA
AND NORTH CENTRAL KANSAS WHERE GOOD MOISTURE POOLING ALONG/NORTH
OF STALLED WARM FRONT IS EXPECTED. I AM NOT CONFIDENT THAT THIS
WILL AFFECT KGLD WITH SW FLOW BRINGING DRIER BL CONDITIONS. KMCK
IS MOST LIKELY TO SEE REDUCED VIS/CIGS WITH LIFR CONDITIONS
DEVELOPING BY 11Z AND IMPROVING BEFORE 16Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR KSZ001>004-014>016-
028-029.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM MST /NOON CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
UPDATE...DR
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
848 AM MST SUN JAN 27 2013
.UPDATE...
ISSUED AT 844 AM MST SUN JAN 27 2013
CANCELLED ADVISORY FOR SHERMAN AND YUMA COUNTIES AND EXTENDED
REMAINING ADVISORY THROUGH 18Z. BASED ON CURRENT TRENDS AND SHORT
RANGE GUIDANCE I EXPECT DENSE FOG TO LINGER LONGER ACROSS MY
NORTHEAST CWA. HRRR WHICH HAS BEST HAND ON CURRENT CONDITIONS
SHOWS FOG DISSIPATING AROUND 18Z IN THE FAR NORTHEAST. THE
WEST/SOUTHWEST EDGE OF FOG/STRATUS IS QUICKLY ERODING AND
CONDITIONS HAVE IMPROVED. FURTHER IMPROVEMENT WILL BE EXPECTED FROM
THE WEST TO THE EAST THROUGH THE REST OF THE MORNING.
UPDATE ISSUED AT 702 AM MST SUN JAN 27 2013
HILL CITY AND WRAY HAVE BOTH REPORTED VISIBILITIES OF 1/4 MILE OR
LESS SO HAVE ADDED THEM TO THE ADVISORY.
UPDATE ISSUED AT 514 AM MST SUN JAN 27 2013
JUST ISSUED A DENSE FOG ADVISORY. AREAS OF DENSE FOG HAVE BECOME
MORE WIDESPREAD OVER MOST OF EXTREME SOUTHWEST NEBRASKA AND THE
FAR NORTH AND NORTHWEST PORTIONS OF NORTHWEST KANSAS. THESE
CONDITIONS HAVE PERSISTED AND GOT WORSE. EVEN DESPITE OF DOWNSLOPE
WINDS...ALBEIT LIGHT...THE DENSE FOG HAS CONTINUE. SMALL SCALE
MODEL OUTPUT HAVING A DIFFICULT TIME GETTING A HANDLE ON THIS. RUC
STARTED OUT WELL BUT IS NOW FADING. HRRR HAS BECOME MUCH BETTER IN
DEPICTING THIS. SO IN ADDITION THE LOCATIONS ALREADY EXPERIENCING
DENSE FOG...ALSO PUT THE ADVISORY INTO RED WILLOW AND NORTON
COUNTIES PER OBSERVATIONAL TRENDS AND BEST MODEL OUTPUT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 419 AM MST SUN JAN 27 2013
MODEL GUIDANCE HAVING A HARD TIME CATCHING ONTO THE STRATUS AND FOG
CURRENTLY AFFECTING BOTH TAF SITES. THE RUC BY FAR IS THE BEST
MODEL. AT THIS TIME EXPECT IFR TO LIFR CONDITIONS THROUGH MID
MORNING WITH KGLD HAVING THE WORST CONDITIONS. AFTER THAT
CONDITIONS SHOULD IMPROVE TO MVFR BY LATE MORNING WITH VFR CONDITIONS
PREVAILING NEAR OR SHORTLY AFTER 18Z OR 19Z. IN THE LATER PORTION OF
THE PERIOD AT KMCK...FOG IS EXPECTED TO DEVELOP ONCE AGAIN. AT THIS
TIME IT LOOKS LIKE THE FOG REMAINS EAST OF KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR KSZ001>004-014>016.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM MST /NOON CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
UPDATE...DR
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
703 AM MST SUN JAN 27 2013
.UPDATE...
ISSUED AT 702 AM MST SUN JAN 27 2013
HILL CITY AND WRAY HAVE BOTH REPORTED VISIBILITIES OF 1/4 MILE OR
LESS SO HAVE ADDED THEM TO THE ADVISORY.
UPDATE ISSUED AT 514 AM MST SUN JAN 27 2013
JUST ISSUED A DENSE FOG ADVISORY. AREAS OF DENSE FOG HAVE BECOME
MORE WIDESPREAD OVER MOST OF EXTREME SOUTHWEST NEBRASKA AND THE
FAR NORTH AND NORTHWEST PORTIONS OF NORTHWEST KANSAS. THESE
CONDITIONS HAVE PERSISTED AND GOT WORSE. EVEN DESPITE OF DOWNSLOPE
WINDS...ALBEIT LIGHT...THE DENSE FOG HAS CONTINUE. SMALL SCALE
MODEL OUTPUT HAVING A DIFFICULT TIME GETTING A HANDLE ON THIS. RUC
STARTED OUT WELL BUT IS NOW FADING. HRRR HAS BECOME MUCH BETTER IN
DEPICTING THIS. SO IN ADDITION THE LOCATIONS ALREADY EXPERIENCING
DENSE FOG...ALSO PUT THE ADVISORY INTO RED WILLOW AND NORTON
COUNTIES PER OBSERVATIONAL TRENDS AND BEST MODEL OUTPUT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 419 AM MST SUN JAN 27 2013
MODEL GUIDANCE HAVING A HARD TIME CATCHING ONTO THE STRATUS AND FOG
CURRENTLY AFFECTING BOTH TAF SITES. THE RUC BY FAR IS THE BEST
MODEL. AT THIS TIME EXPECT IFR TO LIFR CONDITIONS THROUGH MID
MORNING WITH KGLD HAVING THE WORST CONDITIONS. AFTER THAT
CONDITIONS SHOULD IMPROVE TO MVFR BY LATE MORNING WITH VFR CONDITIONS
PREVAILING NEAR OR SHORTLY AFTER 18Z OR 19Z. IN THE LATER PORTION OF
THE PERIOD AT KMCK...FOG IS EXPECTED TO DEVELOP ONCE AGAIN. AT THIS
TIME IT LOOKS LIKE THE FOG REMAINS EAST OF KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
KSZ001>004-013>016.
CO...DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR COZ090.
NE...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
536 AM MST SUN JAN 27 2013
.UPDATE...
ISSUED AT 514 AM MST SUN JAN 27 2013
JUST ISSUED A DENSE FOG ADVISORY. AREAS OF DENSE FOG HAVE BECOME
MORE WIDESPREAD OVER MOST OF EXTREME SOUTHWEST NEBRASKA AND THE
FAR NORTH AND NORTHWEST PORTIONS OF NORTHWEST KANSAS. THESE
CONDITIONS HAVE PERSISTED AND GOT WORSE. EVEN DESPITE OF DOWNSLOPE
WINDS...ALBEIT LIGHT...THE DENSE FOG HAS CONTINUE. SMALL SCALE
MODEL OUTPUT HAVING A DIFFICULT TIME GETTING A HANDLE ON THIS. RUC
STARTED OUT WELL BUT IS NOW FADING. HRRR HAS BECOME MUCH BETTER IN
DEPICTING THIS. SO IN ADDITION THE LOCATIONS ALREADY EXPERIENCING
DENSE FOG...ALSO PUT THE ADVISORY INTO RED WILLOW AND NORTON
COUNTIES PER OBSERVATIONAL TRENDS AND BEST MODEL OUTPUT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 419 AM MST SUN JAN 27 2013
MODEL GUIDANCE HAVING A HARD TIME CATCHING ONTO THE STRATUS AND FOG
CURRENTLY AFFECTING BOTH TAF SITES. THE RUC BY FAR IS THE BEST
MODEL. AT THIS TIME EXPECT IFR TO LIFR CONDITIONS THROUGH MID
MORNING WITH KGLD HAVING THE WORST CONDITIONS. AFTER THAT
CONDITIONS SHOULD IMPROVE TO MVFR BY LATE MORNING WITH VFR CONDITIONS
PREVAILING NEAR OR SHORTLY AFTER 18Z OR 19Z. IN THE LATER PORTION OF
THE PERIOD AT KMCK...FOG IS EXPECTED TO DEVELOP ONCE AGAIN. AT THIS
TIME IT LOOKS LIKE THE FOG REMAINS EAST OF KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
KSZ001>004-013-014.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
UPDATE...BULLER
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
419 AM MST SUN JAN 27 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 419 AM MST SUN JAN 27 2013
NUMEROUS FORECAST PROBLEMS THROUGH THE SHORT TERM. SATELLITE SHOWING
A COMPLICATED AND AMPLIFIED FLOW FROM THE PACIFIC INTO WESTERN
NORTH AMERICA. FLOW IS SPLITTING OVER THE WESTERN PORTION OF THE
COUNTRY. AN UNORGANIZED TROUGH WITH SMALLER WAVES WITHIN IT IS
MOVING THROUGH THE AREA AT THIS TIME. THIS SYSTEM BROUGHT LIGHT RAIN
TO THE AREA. THIS RAINFALL HAS MOVED NORTH OF THE AREA.
MODELS INITIALIZED FINE ON THE JET. UPPER AIR ANALYSIS AND ESPECIALLY
SATELLITE SHOWS THAT THE GFS AND ECMWF ARE HANDLING THE MID LEVELS
THE BEST...ESPECIALLY IN OUR AREA. NAM DID NOT HAVE ANY PRECIPITATION
OVER THE AREA TONIGHT. MODELS ARE HAVING A HARD TIME PLACING THE FOG
AND STRATUS RIGHT NOW. MODELS WERE ALSO HAVING TROUBLE AT THE
SURFACE. THE RUC AND ECMWF WERE DOING THE BEST. MODELS WERE CLOSE ON
THE LOW LEVEL THERMAL FIELD WITH THE ECMWF AND UKMET DOING A LITTLE
BETTER THAN THE GFS AND CANADIAN
TODAY/TONIGHT...INITIAL PROBLEM WILL BE CLOUDS AND FOG. MODELS DOING
A POOR JOB IN DEPICTING THIS REALITY AT THIS TIME. THE RUC AND TO A
LESSER EXTENT THE HRRR IS GETTING THIS. PLAN ON WATCHING TRENDS AS
LONG AS POSSIBLE BEFORE ADJUSTING THE BEST OUTPUT WITH THAT. MODELS
HANG CLOUDS AROUND A WHILE. VERY DRY AIR PER SATELLITE AND ANALYSIS
SHOULD QUICKLY WORK ITS WAY INTO THE AREA BY 18Z. SO EXPECT MOST OF
THE CLOUD COVER AT ALL LEVELS TO BE GONE.
LATEST GUIDANCE HAS BACKED OFF ON THE WINDS AND WILL ADJUST
ACCORDINGLY. COMBINATION OF DOWNSLOPE WINDS AND LITTLE CLOUD COVER
SHOULD ALLOW FOR A GOOD WARM UP. ANALYSIS SHOWS THAT AIR MASS WILL
BE NEARLY THE SAME AS YESTERDAY. ALTHOUGH THE 06Z NAM BACKED OFF
ITS EARLIER WARMER TEMPERATURES BUT IS STILL VERY MILD. HAVE KEPT
THE MAXES THE NEARLY THE SAME BUT POTENTIAL THERE THAT MAXES COULD
BE WARMER.
LIGHT WINDS ON THE BACK SIDE OF THE SURFACE RIDGE DEVELOP OVER THE
EASTERN HALF OR SO. BOUNDARY LAYER RH INCREASES IN THIS SAME AREA.
AIR MASS LOOKS TO CHANGE LITTLE SO THAT MAKES SENSE. PREVIOUS
FORECAST HAD FOG IN THERE AND LEFT THE FOG FORECAST ALONE. LIGHTER
WINDS EAST WILL MAKE FOR COOLER MINS WITH WARMER MINS FURTHER WEST
WITH DOWNSLOPING AND SOME WARM AIR ADVECTION.
MONDAY/MONDAY NIGHT...LEFT THE MORNING FOG IN THERE. MAY HAVE SOME
LOW LEVEL CLOUD COVER IN THERE WITH SOME INCREASE IN MID AND HIGH
LEVEL CLOUD COVER. MODELS HAVE MAJOR DIFFERENCES IN THE AMOUNT OF
WARMUP FOR THIS DAY. 06Z NAM HAS SLOWED ITS ARRIVAL OF THE COLD FRONT
AND IS NOW NEAR TO SLIGHTLY SLOWER THAN THE ECMWF WHICH LOOKS BETTER
IN HANDLING THIS. IN FACT THE ECMWF LOOKS THE FASTEST WITH REMAINING
NEAR TO MUCH SLOWER THAN IT. AS A RESULT THE FRONT LOOKS TO ONLY MAKE
IT INTO THE NORTHERN PORTION BY LATE IN THE DAY. IF THE CLOUDS DO
NOT MESS UP THE TEMPERATURES...IT COULD END UP BEING VERY WARM
ESPECIALLY IN THE SOUTHEAST HALF WHICH SHOULD GET THE WHOLE DAY OF
HEATING. CONSIDERING THE TREND ON THE FRONTAL ARRIVAL AND THE
INCREASE IN THE TEMPERATURE GUIDANCE...WARMED UP THE MAXES...
ESPECIALLY IN THE SOUTHEAST WHICH COULD GET CLOSE TO 70.
IF THIS SCENARIO PANS OUT...THE FAR WESTERN PORTION OF THE FORECAST
AREA GETS CLOSE TO 20 PERCENT RELATIVE HUMIDITY AND GUSTS NEAR 25
MPH. THE DAY SHIFT WILL HAVE TO TAKE ANOTHER LOOK AT THIS.
FRONT BLASTS THROUGH DURING THE NIGHT. GRADIENT AND RATHER HIGH 3
HOUR PRESSURE RISES WOULD INDICATE WINDY CONDITIONS DURING THE
EVENING BEHIND THE FRONT. A RATHER STRONG SOUTHWEST TO NORTHEAST JET
BEGINS TO MOVE ACROSS THE AREA DURING THE DAY AND EVENING. THIS PUTS
THE SOUTHEAST HALF OF THE AREA IN THE RIGHT REAR QUADRANT DURING THE
AFTERNOON AND INTO THE EVENING HOURS. EVEN THOUGH MAY BE HERE IN THE
AFTERNOON...THE MOISTURE PROFILE DOES NOT SUPPORT ANY PRECIPITATION
BEFORE 00Z.
LIFT AND MOISTURE DO COME IN AFTER 00Z. HOWEVER THEY DO NOT SYNC UP
WELL. THE LIFT AND EVEN SOME INSTABILITY ARE FURTHER TO THE EAST THAN
THE DEEPEST MOISTURE. LIFT AND MOISTURE PROFILES MATCH UP WELL WITH
THE DETERMINISTIC AND HPC QPF. THIS IS ALSO SUPPORTED BY THE
GEFS/SREF PRECIPITATION PROBABILITIES. ALL THIS MEANS THAT THE
NORTHWEST HALF WILL SEE THE BEST CHANCE OF PRECIPITATION. WITH ALL
THE NEW DATA SUPPORTING THE CURRENT FORECAST VERY WELL...DID NOT
MAKE ANY CHANGES TO IT.
TUESDAY/TUESDAY NIGHT...AGAIN NEW GUIDANCE IS VERY SUPPORTIVE OF THE
CHANCE OF PRECIPITATION/PRECIPITATION TYPE FORECAST THROUGH THE
MORNING. SO LEFT THOSE GRIDS THROUGH 18Z ALONE. MOST OF THE LIFT AND
MOISTURE IS GONE BY 18Z. LINGERING FLURRIES OR SPRINKLES IN THE
AFTERNOON WILL BE MORE LIKELY THAN MEASURABLE SO MADE THAT CHANGE.
COLD FRONT WILL BE SOUTH OF THE AREA BY THE BEGINNING OF THE
DAY. DEFINITELY WILL BE COOLER WITH THE MODELS SURPRISINGLY IN GOOD
AGREEMENT. PROBLEM IS THAT THE AGREEMENT IS WARMER THAN CURRENT
FORECAST. WITH THE POSSIBILITY OF A DECENT AMOUNT OF SUN AND SOME
DOWNSLOPE WINDS CAN DEFINITELY SEE THE WARMER TEMPERATURES. SO RAISED
THE MAXES A LITTLE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 419 AM MST SUN JAN 27 2013
THE LONGWAVE TROUGH THAT BROUGHT PRECIPITATION CHANCES EARLY THIS
WEEK WILL BE OVER THE EASTERN HALF OF THE CONUS THROUGH FRIDAY. THE
NORTHWEST UPPER LEVEL FLOW WILL ALLOW A COLD FRONT TO LINGER OVER
THE NORTHEAST INTO FRIDAY. DURING THE WEEKEND THE UPPER LEVEL
RIDGE OVER THE WEST COAST WILL BEGIN TO BUILD EAST INTO THE PLAINS.
THURSDAY THE LONGWAVE TROUGH BROADENS AS A SHORT WAVE TROUGH MOVES
THROUGH THE FLOW INTO THE PLAINS. PRECIPITATION CHANCES RETURN
WEDNESDAY NIGHT AND THURSDAY AS THE SHORT WAVE TROUGH MOVES OVER THE
FRONT AND 1000-500MB MOISTURE INCREASES. SNOW WEDNESDAY NIGHT WILL
TRANSITION TO RAIN THURSDAY AFTERNOON AS TEMPERATURES WARM INTO THE
MID/UPPER 30S TO AROUND 40. PRECIPITATION CHANCES COME TO AN END AS
DRIER AIR FOLLOW THE SHORT WAVE TROUGH AXIS INTO THE AREA.
SATURDAY ANOTHER SHORT WAVE TROUGH MOVES OVER THE AREA. HOWEVER
1000-500MB MOISTURE DECLINES AS THE TROUGH MOVES INTO THE
PLAINS...SO THERE MAY ONLY BE ENOUGH MOISTURE FOR SOME CLOUDS TO
DEVELOP BY THE TIME THE TROUGH ENTERS THE HIGH PLAINS.
TEMPERATURES WILL BE BELOW NORMAL EAST OF THE COLD FRONT WITH NEAR
NORMAL VALUES TO THE WEST THROUGH THURSDAY. NEAR TO ABOVE NORMAL
TEMPERATURES WILL MOVE INTO THE AREA FRIDAY AND THE WEEKEND AS THE
UPPER LEVEL RIDGE BUILDS EASTWARD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 419 AM MST SUN JAN 27 2013
MODEL GUIDANCE HAVING A HARD TIME CATCHING ONTO THE STRATUS AND FOG
CURRENTLY AFFECTING BOTH TAF SITES. THE RUC BY FAR IS THE BEST
MODEL. AT THIS TIME EXPECT IFR TO LIFR CONDITIONS THROUGH MID
MORNING WITH KGLD HAVING THE WORST CONDITIONS. AFTER THAT
CONDITIONS SHOULD IMPROVE TO MVFR BY LATE MORNING WITH VFR CONDITIONS
PREVAILING NEAR OR SHORTLY AFTER 18Z OR 19Z. IN THE LATER PORTION OF
THE PERIOD AT KMCK...FOG IS EXPECTED TO DEVELOP ONCE AGAIN. AT THIS
TIME IT LOOKS LIKE THE FOG REMAINS EAST OF KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1011 PM MST SAT JAN 26 2013
.UPDATE...
ISSUED AT 755 PM MST SAT JAN 26 2013
UPDATE SENT FOR TONIGHT-SUNDAY PERIOD.
AT 03Z WARM FRONT AND LIGHT RAIN PUSHING INTO THE SOUTHWEST AND
WESTERN PART OF THE FORECAST AREA. AS THE WARM FRONT LIFTS
NORTH/NORTHEAST OVERNIGHT EXPECT SOME RAIN ALONG AND NORTH OF IT
WHILE TO THE SOUTH DECREASING CLOUDINESS EXPECTED. EXCEPTION WILL
BE ACROSS THE EASTERN 1/3-1/4 OF THE AREA WHERE SOUTHERLY
COMPONENT TO THE WIND WILL MAINTAIN HIGH BOUNDARY LAYER MOISTURE
AND A THREAT FOR FOG.
AS THE SYSTEM CONTINUES TO LIFT EAST/NORTHEAST ON SUNDAY NORTHWEST
WINDS WILL DEVELOP ON THE BACKSIDE PUSHING THE LOW CLOUDS AND FOG
OUT OF THE AREA BY MID TO LATE MORNING. ELSEWHERE MAY SEE SOME
WRAPAROUND CLOUDINESS EARLY WITH NO PRECIPITATION EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 135 PM MST SAT JAN 26 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE RIDGING ACROSS
THE SOUTHERN PLAINS WITH A SERIES OF SHORTWAVE TROUGHS OVER SOUTHERN
CALIFORNIA AND OFF THE PACIFIC NW COAST. THE FIRST OF THESE TROUGHS
OVER SOUTHERN CALIFORNIA WILL BE THE MAIN WEATHER PRODUCER FOR US
TONIGHT WITH MID-HIGH CLOUDS ALREADY INCREASING AHEAD OF THIS
FEATURE OVER COLORADO AND WESTERN KS.
GUIDANCE IN GENERAL AGREEMENT ON PRECIP SPREADING FROM THE WEST TO
THE EAST THROUGH THE EVENING HOURS...WITH BEST COVERAGE/CHANCES
ACROSS THE EAST/NORTHEAST AFTER MIDNIGHT AS A WARM FRONT MOVES NORTH
AND MOISTURE ADVECTION INCREASES. IM NOT AS CONFIDENT ABOUT COVERAGE
DURING THE EVENING WITH MOISTURE ADVECTION BELOW H7 MARGINAL UNTIL
06Z. NAM IS ADVERTISING DRY SLOT QUICKLY MOVING FROM THE W/SW LATE
THIS EVENING THROUGH SUNDAY MORNING...AND WITH STRONG DRY SLOT
ALREADY APPARENT ON WV IMAGERY THIS MAY BE REASONABLE. I HAVE
TRENDED POPS HIGHER ACROSS THE NORTHEAST AROUND 06-12Z...AND HAVE
DECREASED POPS QUICKER ACROSS THE SW DURING THIS SAME TIME PERIOD.
OVERALL QPF AMOUNTS SHOULD BE LIGHT...WITH HIGHEST TOTALS IN SW
NEBRASKA AND NORTH CENTRAL KS WHERE UP TO 0.10 INCHES OF LIQUID IS
POSSIBLE. AS WITH PREVIOUS FORECASTS I KEPT PRECIP TYPE ALL RAIN
WITH MODEL SOUNDINGS SUPPORTING ALL LIQUID...AND SURFACE
TEMPERATURES EXPECTED TO REMAIN ABOVE FREEZING WHERE PRECIP/CLOUD
COVER IS LINGERING AFTER MIDNIGHT. BELOW FREEZING TEMPS WILL BE
POSSIBLE IN THE W/SW WHERE SKIES WILL BE CLEARING...HOWEVER PRECIP
WILL BE OVER WITH AT THAT POINT. WITH INCREASING LOW LEVEL MOISTURE
ACROSS THE NORTH AND EAST WE COULD ALSO SEE PATCHY FOG DEVELOPMENT
LATE TONIGHT INTO SUNDAY MORNING BEFORE THE WARM FROM FINAL PUSHES
NORTH INTO CENTRAL NEBRASKA BEFORE 18Z...WITH DRY/STABLE CONDITIONS
EXPECTED THROUGH THE REST OF SUNDAY.
WITH CLEARING SKIES...AND 10-14C H85 TEMPS ADVECTING OVER THE CWA
FROM THE WEST WE SHOULD SEE ANOTHER MILD DAY WITH TEMPERATURES IN THE
MIDDLE 60S IN THE SOUTH TO THE LOW 50S NEAR MCCOOK WHERE CLOUD COVER
MAY LINGER LONGER INTO THE AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 135 PM MST SAT JAN 26 2013
MUCH ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH MONDAY.
SYSTEM WILL MOVE THROUGH MONDAY NIGHT BRINGING A CHANCE OF LIGHT
SNOW AND COLDER TEMPERATURES. THERE COULD BE A BRIEF PERIOD OF
LIGHT RAIN AHEAD OF THE FRONT...BUT IT WILL QUICKLY CHANGE TO
SNOW. LIGHT SNOW OR FLURRIES COULD LINGER INTO TUESDAY...MAINLY IN
THE MORNING. TOTAL SNOW ACCUMULATIONS FOR MONDAY NIGHT THROUGH
TUESDAY CURRENTLY FORECAST TO BE AN INCH OR LESS. WIND DOES NOT
APPEAR THAT IT WILL BE A PROBLEM. THE REMAINDER OF THE PERIOD WILL
BE DOMINATED BY NORTHWEST FLOW ALOFT. GFS SHOWS SOME VERY LIGHT
SNOW OR FLURRIES WEDNESDAY NIGHT WITH SUBTLE SHORTWAVE IN THE
FLOW...OTHERWISE DRY. TEMPERATURES WILL SLOWLY REBOUND FROM THE
TUESDAY COOL DOWN...NEAR NORMAL WEDNESDAY AND THURSDAY THEN
SLIGHTLY ABOVE NORMAL FRIDAY AND SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1000 PM MST SAT JAN 26 2013
FOR KGLD VFR THROUGH THE PERIOD. WARM FRONT AND BAND OF LIGHT RAIN
HAS PUSHED JUST TO THE NORTH OF THE TERMINAL AND SHOULD SEE A
DECREASE IN CLOUDINESS TIL SUNDAY MORNING WHEN SOME WRAPAROUND
CLOUDINESS MAY EXTEND AS FAR SOUTH AS THE TERMINAL BEFORE EXITING
THE AREA TO THE EAST/NORTHEAST. SOUTH WINDS 10KTS WILL VEER TO THE
WEST AT 10KTS BY 10Z THEN NORTHWEST BY 17Z WITH GUSTS AROUND 18KTS
POSSIBLE BEFORE BECOMING VRB05KTS BY SUNSET. SOUTH WINDS AROUND
10KTS WILL DEVELOP TOWARD THE END OF THE PERIOD.
FOR KMCK SHOULD HAVE LIGHT RAIN THROUGH 07-08Z THEN SOME FOG WITH
MVFR/IFR CIGS/VIS THROUGH 15-17Z AS WINDS ARE LIGHT AND BOUNDARY
LAYER MOISTURE IS HIGH. DURING THE AFTERNOON HOURS SUNDAY MVFR/IFR
CIGS/VIS WILL MOVE AWAY FROM THE TERMINAL AS WINDS BECOME
NORTHWEST AROUND 10KTS. BY 23Z VRB04KT WINDS EXPECTED AND SHOULD
CONTINUE THROUGH THE REST OF THE TAF PERIOD UNDER GENERALLY A
CLEAR SKY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...DR
LONG TERM...024
AVIATION...99
AREA FORECAST DISCUSSION
NWS JACKSON KY
534 PM EST SUN JAN 27 2013
.UPDATE...
ISSUED AT 534 PM EST SUN JAN 27 2013
UPDATED TO SLOW DOWN PRECIPITATION ONSET. IT LOOKS LIKE THINGS ARE
FINALLY STARTING TO SATURATE UP ENOUGH TO ALLOW FOR SOME LIGHT RAIN
IN THE MONTICELLO/SOMERSET AREA SHORTLY. OTHERWISE...IT WILL REMAIN A
SLOW PROCESS AS RAIN TRIES TO FIGHT TO THE LOW LEVEL DRY AIR. THE RAIN
SHOULD EVENTUALLY WIN OUT...BUT STILL QUESTIONABLE IF THE SOUTHEAST
WILL SEE MUCH IN THE WAY OF RAIN AS THERE WILL LIKELY BE A SOUTHEAST
TO NORTHWEST GRADIENT FOR PLACES THAT RECEIVE RAIN VERSES THOSE WHO
DO NOT. BASED ON LATEST RUC MODEL DATA...RAIN SHOULD BE ON THE WAY
OUT BY 06Z WITH DRIER CONDITIONS EXPECTED FOR THE SECOND HALF OF THE
NIGHT INTO TOMORROW MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 310 PM EST SUN JAN 27 2013
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY AS OF 20Z HAS PRECIP
BEGINNING TO ENTER THE AREA NEAR SOMERSET AHEAD OF A DEVELOPING WARM
FRONT. AT THIS POINT...SURFACE OBS HAVE SHOWN NO PRECIP MAKING IT TO
THE GROUND IN THE SOUTH. BASED ON THE PERSISTENCE OF THE MODELS
BRINGING IN THE PRECIP LATE THIS AFTERNOON AND INTO THE EARLY
EVENING...WILL KEEP A SLIGHT CHANCE INTO THIS EARLY AFTERNOON WITH
THE RAIN OVER SPREADING THE REST OF EASTERN KENTUCKY THIS EVENING.
EXPECT RAIN TO CONTINUE THROUGH THE NIGHT. CONCERNS WITH THE TIMING
OF THE PASSING WARM FRONT LOOK TO BE AROUND 12Z WITH A 30 TO 40 KNOT
LL JET OVERHEAD. THIS WILL LEAD TO SOME 20 KNOT SOUTHWEST WINDS
MIXING TO THE SURFACE FOR MONDAY. MORE SHOWERY PRECIP ENTERS THE AREA
BY MONDAY AFTERNOON AS EASTERN KENTUCKY WILL BE IN THE WARM SECTOR
FOR THE REST OF THE SHORT TERM. THE SURGE OF WARM AIR WILL BRING
HIGHS FOR MONDAY INTO THE LOWER 60S...NEARLY 5 DEGREES SHORT OF
RECORD VALUES. SHOWER ACTIVITY WILL CONTINUE THROUGH MONDAY NIGHT AS
WELL WITH MODELS HANDLING THE SET UP QUITE WELL.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 351 PM EST SUN JAN 27 2013
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE NEXT
FRONT. THE LEADING EDGE OF THE FRONT IS GOING TO BRING SOME SHOWERS
TO THE BLUEGRASS ON TUESDAY MORNING. AS THE FRONT GETS
NEARER...SHOWERS WILL SPREAD ACROSS EASTERN KENTUCKY DURING THE
TUESDAY EVENING. THE LATEST ECMWF IS SLOWING THIS DOWN A LITTLE...SO
WILL NOT BE SURPRISED TO SEE THE FRONT SLOW DOWN AS THE TIME GETS
NEARER. THE FRONT WILL ACTUALLY BE MOVING THROUGH THE AREA ON
WEDNESDAY MORNING. THE NAM BUFR WAS SHOWING THE BEST INSTABILITY TO
BE VERY NEAR THE FRONT ITSELF AND THIS IS WHERE THUNDERSTORMS WILL
BE MOST LIKELY. THERE IS VERY STRONG SHEAR WITH THE FRONT...HOWEVER
THE INSTABILITY IS MARGINAL...SO THE SEVERE POTENTIAL IS LOW...BUT
NOT ZERO. IF THE FRONT SLOWS DOWN...THE THE SEVERE POTENTIAL WILL BE
GREATER. WILL NEED TO BE VIGILANT TO SEE HOW THIS PLAYS OUT. ONCE THE
POST FRONTAL SHOWERS MOVE INTO WEST VIRGINIA BY TUESDAY MORNING...THE
WILL BE A SHORT RESPITE...UNTIL A CLIPPER SYSTEM MOVES THROUGH THE
AREA ON THURSDAY NIGHT. THE LOOKS TO BE A LIGHT SNOWFALL WITH ABOUT
AN INCH EXPECTED. THIS WOULD BE A STUDENTS DREAM AND GIVE THEM
ANOTHER THREE DAY WEEKEND. HIGH PRESSURE WILL THEN DOMINATE UNTIL
ANOTHER WEAK SYSTEM MOVES THROUGH THE AREA ON SATURDAY NIGHT. SO THIS
WILL BE AN ACTIVE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1251 PM EST SUN JAN 27 2013
EXPECT CIRRUS TO CONTINUE TO OVER SPREAD EASTERN KENTUCKY THIS
EVENING. BY 00Z MID AND LOW LEVEL CLOUD COVER WILL BEGIN TO MOVE INTO
THE AREA. WHILE MOST CEILINGS WILL STILL BE VFR A FEW MVFR CEILINGS
WILL MOVE INTO THE AREA ALONG WITH SOME MVFR VISIBILITY IN LIGHT RAIN.
BY MONDAY AFTERNOON...SOUTHWEST WINDS WILL INCREASE TO 10 KNOTS AND
GUSTING TO 20 AT TIMES. RAIN BY TOMORROW AFTERNOON SHOULD HAVE LIFTED
OFF TO THE NORTH LEAVING VFR TO MVFR CEILINGS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SHALLENBERGER
LONG TERM....JJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
408 PM EST SUN JAN 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFFSHORE TONIGHT AND EARLY MONDAY...AS A
WARM FRONT LIFTS NORTH OF THE AREA LATE TONIGHT THROUGH MONDAY
MORNING. THE NEXT COLD FRONTAL PASSAGE IS EXPECTED DURING THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
LATEST WX ANALYSIS SHOWS 1030+MB SFC HIGH PRESSURE OVER THE NE
US, RIDGING DOWN THE EASTERN SEABOARD. TO THE WEST, COMPLEX WX
SYSTEM ROLLING ACROSS THE MIDDLE AND UPPER MS VLY THIS AFTERNOON.
ALOFT, DEEP TROUGH IS DIPPING ALONG THE WEST COAST, WHICH IS
ALLOWING FOR INCREASED LONGWAVE RIDGING OVER THE EASTERN THIRD OF
THE COUNTRY. A PAIR OF NOTABLE UPPER SHORTWAVES EVIDENT ON WV SAT
THIS AFTN. FIRST ACROSS THE NORTHERN PLAINS/UPPER MIDWEST, WITH
ANOTHER S/W SLIDING NE ACROSS THE LOWER OHIO VALLEY. IT IS THIS
FEATURE THAT WILL NEED WATCHING FOR THE BALANCE OF THE NIGHT INTO
TOMORROW. CLOUDS THAT WERE TRAPPED BENEATH LLVL INVERSION EARLIER
TODAY HAVE ERODED OVER MUCH OF THE AREA. LAST VESTIGES OF LOW CLDS
PUSHED OUT OF FAR WESTERN ZONES JUST IN TIME FOR SOME INCREASING
MID/HI CLDS AHEAD OF THE OHIO VLY SYSTEM. WL ACCOUNT FOR SLOW
INCREASE IN CLDS LATE TONIGHT TOWARDS MON MORNING.
SFC HI PRESSURE WL VERY SLOWLY ERODE/MOVE OFF THE CST TNGT.
HOWEVER AS PER USUAL WITH HIGH PRES WEDGED AGAINST THE MTNS, THIS
WL OCCUR SLOWLY...AND LKLY SLOWER THAN CURRENTLY DEPICTED. CLOUDS
WILL CONTINUE TO THICKEN AND LOWER AS SYSTEM AND ASSOCIATED WARM
FRONT APPROACHES FM THE SW. TEMPS LKLY TO DROP THIS EVE/ERY TNGT
INTO THE M/U20S...BEFORE HOLDING STEADY/SLOWLY RISING AFTER
MIDNIGHT. FORECAST BUFR SOUNDINGS CONTINUE TO SHOW A RATHER STOUT
WARM NOSE ALOFT...AROUND 4-5C SURGING INTO THE AREA AROUND THIS
TIME, ALLOWING FOR ARRIVING OVERRUNNING MOISTURE TO FALL INTO A
RELATIVELY SHALLOW SUB-FREEZING BOUNDARY LAYER. LOW LVLS REMAIN SLOW
TO SATURATE BEFORE 09-14Z/28 OVR WESTERN/CENTRAL SECTIONS OF FA AS WAA
ALOFT ENSUES IN EARNEST LATE TONIGHT. THUS, ANY FZRA WOULD OCCUR
AFTER MIDNIGHT TNGT.
UPSHOT OF THIS IS THAT ANY PCPN THAT FALLS PRIOR TO MID-MORNING
MONDAY WILL MOST LIKELY BE FZRA, WITH PERHAPS SOME SLEET/IP AT THE
START NW OF RIC. GENERAL MODEL AGREEMENT CONTINUES FOR SOME LGT
PCPN REACHING FAR WESTERN COUNTIES BY DAYBREAK MON. QPF CONTINUES TO
BE QUITE LIGHT...BUT SFC TEMPS LIKELY TO BE AOB FREEZING AS CAD
WEDGE REMAINS STUBBORN. MONITORING UPSTREAM RADAR TRENDS...CONFIDENT
IN RUC DEPICTION IN TAKING BEST SWATH/SLUG OF OVERRUNNING MOISTURE
ALONG AND NORTH OF FVX-OFP LINE, AND HV ELEVATED TO LKLY POP ALONG
AND NORTHWEST OF RIC METRO AREA. POTENTIAL ACCUM OF ICE LESS THAN A
TENTH/FEW HUNDREDTHS OF AN INCH. HAVE ISSUED FZRA ADVY FOR AREAS
ALONG AND NORTH OF I-85/WEST OF I-95. FARTHER E/SE...CONFIDENCE
IN ACCUMULATING PCPN/ICE ACCRETION IS MUCH LOWER. EVENING CREW
WILL CONTINUE MONITORING TRENDS, AND COULD ISSUE FARTHER EAST IF
NEED BE. CAD WEDGE SLOWLY ERODES MONDAY, WITH TEMPS WARMING ABOVE
FREEZING MON MORNING. ENDED HEADLINE AT 9AM AFTER COORD WITH
NEIGHBORING OFFICES...AS BL SHOULD WARM TO AOA FREEZING BY THIS
TIME.
PCPN BEGINS TO MOVE TO THE ENE THROUGH/AWAY FM THE FA IN THE
AFTN. SFC WARM FRONT NNE OF THE FA BY EVE...AND FA RMNS IN WRM
SECTOR FOR MON NGT/TUE W/ VRB CLDNS. POPS IN THE AFTN TO BE GENLY
AOB 14% S...AND ONLY SLGT CHC FAR N.
HI TEMPS MON FM THE L40S N TO ARND 50F SE.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
WARM AIR QUICKLY STREAMS INTO THE AREA AS WARM FRONT SURGES
NORTHWARD. WITH WEAK MIXING EXPECTED MON NIGHT AND EARLY ON
TUESDAY WL NEED TO WATCH PROGRESS OF WEDGE ACROSS THE NORTHWEST,
BUT FOR NOW INCRIMENTALLY NUDGED TEMPS UPWARDS. AS IS TYPICAL IN
STRONG WAA SETUP SUCH AS THIS, SOME LOW STRATUS/FOG WL BE POSSIBLE
LATE MON NIGHT AND TUE MORNING. OTHERWISE, ONCE LLVL INVERSION
GETS BROKEN, EXPECT MARKEDLY WARMER CONDS ON TUESDAY AS SFC HIGH
NUDGES FARTHER OFFSHORE AND WARM RETURN FLOW SETS UP. LO TEMPS MON
NGT MNLY IN THE L/M40S. HIGHS IN THE U50S TO L60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WILL EJECT FROM THE
DEEP SOUTH INTO THE MID ATLANTIC REGION WEDNESDAY AFTERNOON. SFC LOW
WILL LOCATE OVER THE GREAT LAKES WITH THE COLD FRONT EXTENDING SW
INTO THE LOWER MS RIVER VALLEY. WHILE TIMING AND SPATIAL DIFFERENCES
STILL EXIST...ECMWF MORE AMPLIFIED AND SLIGHTLY SLOWER THAN GFS...A
WARM/WET/WINDY DAY IS ON TAP FOR THE FA. DEEP SWLY FLOW WILL RESULT
IN STRONG MOISTURE ADVECTION INTO THE REGION...ORIGINATING FROM THE
GULF OF MEXICO (EVIDENT IN 700MB THETA E RIDGE). PRECIP WATERS WILL
INCREASE TO AROUND 1.5" (OVER 2 STD ABOVE NORMAL FOR JANUARY).
COLD FRONT EXPECTED TO CROSS THE FA WED LATE AFTERNOON THROUGH
LATE WED NIGHT. DIVERGENCE ALOFT (RRQ OF 160+ KT 300MB JET) AND
VORT MAX/SHORTWAVE WILL PROVIDE FORCING FOR ASCENT ACROSS THE
REGION. MARGINAL LAPSE RATES...SHEAR AND LITTLE...IF ANY CAPE IN
THE MIXED PHASE LAYER WILL LIKELY LIMIT CHANCE OF THUNDER WEDS
AFTERNOON. WILL LEAVE OUT ANY MENTION OF THUNDER IN THE
GRIDS/ZONES FOR NOW...BUT MAY NEED TO BE ADDED LATER WHEN MODELS
HAVE A BETTER HANDLING ON THE DEVELOPING SYSTEM. HAVE INCREASED
POPS TO CATEGORICAL WEDS AFTERNOON/EVENING ACROSS THE REGION.
LIGHT SHOWERS WILL BE POSSIBLE WEDS MORNING/EARLY AFTERNOON ACROSS
THE PIEDMONT. ABUNDANT MOISTURE AND STRONG FRONTOGENETIC FORCING
COULD ALSO LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL ACROSS
THE REGION. QPF AMOUNTS FORECAST TO GENERALLY RANGE FROM ONE
QUARTER TO ONE HALF INCH WITH LOCALLY HIGHER AMOUNTS. PRECIP WILL
END QUICKLY W TO E EARLY THURS MORNING AS DEEP...DRY WLY FLOW
KICKS IN.
STRONG WAA AND INCREASING HEIGHT/THICKNESS VALUES IN ADVANCE OF THE
FRONT (850 TEMPS WARMING TO NEAR +14C) WILL RESULT IN A WARM/HUMID
DAY. WHILE DAYTIME MIXING WILL BE WEAK WITH LACK OF SUNSHINE...BL
WINDS WILL BE ENOUGH FOR SLY SFC WINDS 15 TO 20 MPH WITH GUSTS UP TO
25 MPH. WHILE CLOUD COVER/LACK OF STRONG MIXING WILL LIMIT TEMPS
FROM REACHING THEIR FULL POTENTIAL...HIGHS STILL EXPECTED TO REACH
INTO THE UPPER 60S/LOW 70S ACROSS THE FA.
IN WAKE OF THE DEPARTING SYSTEM...TROUGHING WILL REMAIN OVER THE
REGION THURSDAY AS HEIGHT/THICKNESS FALLS RESULT IN COLDER TEMPS
THURSDAY (MID 40S N TO MID 50S). ADDITIONAL ENERGY WILL DIVE DOWN
THE BACKSIDE OF THE TROUGH THURS AFTERNOON...LOCATING OVER THE OH
VALLEY FRIDAY MORNING AS A WEAK LEE SIDE SFC TROUGH DEVELOPS.
MOISTURE MAY BE A CONCERN...BUT HAVE OPTED TO MENTION SLIGHT
CHANCE/CHANCE POPS ACROSS THE FA. PTYPE WILL BE A CONCERN...WITH
SNOW SHOWERS POSSIBLE ACROSS THE NRN FA.
ARCTIC HIGH PRESSURE WILL BUILD OVER THE MID ATLANTIC FRIDAY NIGHT
INTO SATURDAY AS A CLIPPER SYSTEM DIVES OVER THE GREAT LAKES EARLY
SATURDAY. TEMPS EXPECTED TO REMAIN BELOW NORMAL THROUGH THE WEEKEND.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
SFC HIGH PRESSURE WILL SLIDE SE ACROSS THE AREA TODAY AND THEN
MOVE OFF THE COAST THIS EVENING FOR CONTINUED VFR CONDITIONS.
LIGHT AND VARIABLE WINDS WILL BECOME SE-S OVERNIGHT INTO MON.
MEANWHILE...A WEAK UPPER LEVEL SYS WILL APPROACH THE AREA. THIS
SYS COULD BRING SOME MVFR/IFR CONDS WITH -RA OR PSBL CHC FOR BRIEF
WINTRY MIX EARLY MONDAY MORNING AS THE WARMER MOIST AIR OVER RUNS
THE COOLER AIR AT THE SURFACE. THE FLOW TURNS MORE SOUTHERLY
MONDAY AFTERNOON THROUGH WEDNESDAY WITH VFR CONDITIONS. THE
ARRIVAL OF A COLD FRONT LATER WEDNESDAY INTO THURSDAY COULD
PRODUCE MORE MVFR/IFR CONDITIONS ONCE AGAIN.
&&
.MARINE...
HIGH PRESSURE HAS SETTLED OVER THE WATERS THIS AFTERNOON RESULTING
IN LIGHT N/NWLY WINDS. N/NE SWELL RESULTED IN A PERIOD OF HIGH SEAS
OVER THE SRN COASTAL WATERS AND THE ISSUANCE OF SCA HEADLINES. SEAS
HAVE REMAINED AROUND 4 FT...BUT ANTICIPATED TO REMAIN BELOW SCA
CRITERIA. HIGH PRESSURE WILL SLIDE SE TONIGHT AND AS A WARM FRONT
LIFTS THROUGH THE MID ATLANTIC. AS THIS OCCURS...FLOW WILL BECOME
S/SW AND SUB SCA LEVELS. SW FLOW WILL INCREASE MONDAY AFTERNOON INTO
MONDAY NIGHT TO AROUND 15 KT (15-20 KT OVER THE NRN COASTAL WATERS)
AS LOW LEVEL PRESSURE GRADIENT TIGHTENS BTWN DEPARTING HIGH PRESSURE
AND STRONG LOW PRESSURE OVER THE CNTRL CONUS.
THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL APPROACH THE REGION
TUESDAY NIGHT AND WEDNESDAY...PUSHING A STRONG COLD FRONT TOWARD THE
REGION LATE IN THE DAY. AHEAD OF THE FRONT...A STRONG LOW-LEVEL JET
WILL DEVELOP OVER THE REGION AND THE WATERS. WHILE THE STRONGEST
WINDS WILL REMAIN ALOFT (>40 KTS AT 1K FT)...ENOUGH WIND WILL REACH
THE WATER LEVEL TO WARRANT SCA CONDITIONS OVER ALL WATERS INTO EARLY
THURS MORNING. SEAS RAPIDLY BUILD WED AFTERNOON...REACHING UP TO 8
TO 10 FT 20 NM OUT LATE. COLD FRONT EXPECTED TO CROSS THE WATERS
EARLY THURS MORNING ACCOMPANIED BY MODEST CAA.
UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEKEND AS A SERIES OF
DISTURBANCES CROSS THE WATERS. ADDITIONAL SCA HEADLINES WILL LIKELY
BE NEEDED THURSDAY AND FRIDAY...AND POSSIBLY INTO THE WEEKEND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST
MONDAY FOR VAZ048-049-060>071-079-080.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM/ALB
SHORT TERM...MAM
LONG TERM...SAM
AVIATION...JEF
MARINE...SAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
528 AM EST SUN JAN 27 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 421 PM EST SAT JAN 26 2013
LAKE EFFECT HAS BEEN GRADUALLY DIMINISHING THROUGH THE AFTERNOON
HOURS...AS THE NORTHERLY FLOW HAS SLOWED WITH HIGH PRESSURE MOVING
OVER THE CWA. STILL HAVE SOME LIGHT SNOW SHOWERS OVER THE NORTH
CENTRAL CWA...BUT EXPECT THEM TO END OR PUSH NORTH DURING THE LATE
AFTERNOON AND EARLY EVENING. OTHERWISE...A FAIRLY NICE AFTERNOON
WITH LIGHT WINDS AND TEMPERATURES AT OR SLIGHTLY BELOW NORMAL AS OF
3PM.
HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES WILL SHIFT EAST
TONIGHT AS THE UPPER RIDGE BUILDS NORTHEAST INTO THE UPPER
MISSISSIPPI VALLEY. AS THIS OCCURS...BROAD H800-600 WARM AIR
ADVECTION CURRENTLY IN MINNESOTA AND STARTING TO MOVE INTO WESTERN
LAKE SUPERIOR WILL CONTINUE EAST ACROSS THE CWA TONIGHT. SO FAR
TODAY...HAVE ONLY SEEN A FEW OBS REPORTING SNOW SHOWERS FROM THIS
MID CLOUD DECK IN NORTHERN MN...WHICH WAS LIKELY HELD OFF BY DRY
H925-850 AIR SEEN ON 12Z KINL SOUNDING AND RUC SOUNDINGS IN THAT
AREA. LATEST MODELS DO TRY TO MOISTEN THE CENTRAL CWA TOWARDS
MIDNIGHT...AS THE STRONGER H925-850 WAA SLIDES EAST ALONG THE WI
BORDER. NOT LIKING HOW QUICKLY THINGS MOISTEN...BUT WITH THE IDEA IN
SEVERAL MODELS...WILL ADD SLIGHT CHANCES THERE. WILL KEEP THE BEST
POPS OVER THE NORTHERN HALF OF LAKE SUPERIOR WHERE THE LOWER LEVELS
WERE A LITTLE MORE MOIST AND THE MID LEVEL WAA WAS THE STRONGEST.
ALSO ADDED A MENTION OF FLURRIES TO AREAS SURROUNDING THE POPS TO
ACCOUNT FOR SOME SNOW MAKING IT THROUGH THE DRY AIR.
THE OTHER ITEM OF CONCERN HEADING INTO THE OVERNIGHT HOURS WILL BE
THE INCREASED MOISTENING OF THE LOWER LEVELS OFF LAKE MICHIGAN. AS
THIS OCCURS...THE H850 TEMPS WILL BE WARMING TOWARDS -10C
OVERNIGHT...SO DON/T EXPECT LAKE ENHANCEMENT TO GET TOO OUT OF
HAND. BUT WITH THE SNOW ALOFT FEEDING INTO THE LOWER LEVELS FORCING
THAT IS MAINLY BELOW -10C...EXPECT SNOW TO DEVELOP THERE. H925 WINDS
ARE FAVORABLE FOR SOUTHERN LUCE AND SOUTHEAST SCHOOLCRAFT...SO HAVE
INCREASED POPS INTO LOW END LIKELY VALUES FOR THOSE LOCATIONS
AND TAPERED IT OFF FAIRLY QUICKLY TO THE WEST. WITH SNOW RATIOS ON
THE LOW END...AROUND 10-14 TO 1 INITIALLY AND TRENDING
TOWARDS 8-1 SUNDAY MORNING...EXPECT ACCUMULATIONS TO BE FAIRLY LIGHT
IN THOSE AREAS WITH ONLY AN INCH OF ACCUMULATION. THE LAKE EFFECT
SHOULD DIMINISH LATER SUNDAY MORNING INTO THE EARLY AFTERNOON DUE TO
THE CONTINUED WARMING OF TEMPS ALOFT SHOVING INVERSION HEIGHTS TO
3KFT.
SUNDAY LOOKS TO BE FAIRLY QUIET...AS THE AREA IS BETWEEN THE
EXITING WARM AIR ADVECTION PRECIPITATION AND THE NEXT APPROACHING
SYSTEM FOR SUNDAY NIGHT. THE NEXT WAVE IS CURRENTLY OVER
SOUTHERN CALIFORNIA AND QUICKLY MOVES NORTHEAST AND
TOWARDS THE AREA TONIGHT AND SUNDAY. WITH THE INCREASED CONSISTENCY
IN THE MODELS...HAVE DELAYED THE START OF THE PRECIPITATION UNTIL
00Z AND LATER. THE LONG TERM DISCUSSION WILL COVER THIS SYSTEM IN
FURTHER DETAILS.
OTHERWISE...WILL SEE A GAP IN THE CLOUDS BEHIND THE WAA
CLOUDS DEPARTING IN THE MORNING AND THE INCREASING CLOUDS FROM THE
SOUTHWEST IN THE AFTERNOON. THINK THIS CLEARING WILL BE MOST LIKELY
OVER THE WEST HALF AND HAVE TRENDED TOWARDS PARTLY-MOSTLY SUNNY SKY
FOR PERIOD AROUND MID DAY. FARTHER EAST...NAM/GFS ARE HINTING AT
SOME LOWER CLOUDS DEVELOPING TONIGHT AND REMAINING THROUGH MUCH OF
SUNDAY. NOT OVERLY CONFIDENT ON THIS SOLUTION WITH THE DRY AIR
UPSTREAM...BUT WITH THE EXITING MID CLOUDS AND APPROACHING HIGH
CLOUDS...A PARTLY-MOSTLY CLOUDY FORECAST SEEMED WARRANTED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 527 AM EST SUN JAN 27 2013
AT 12Z MONDAY A HIGH AMPLITUDE RIDGE WILL ENCOMPASS MUCH OF THE
CENTRAL AND EASTERN PORTIONS OF THE U.S...WITH A SMALL BUT VERY
SIGNIFICANT WAVE STRETCHING FROM LAKE SUPERIOR TO N WI. THE LARGER
TROUGH WILL BE SET UP FROM SASKATCHEWAN THROUGH ID AND S CA. ZONAL
FLOW WILL QUICKLY TURN TO SW FLOW ALOFT MONDAY AFTERNOON AHEAD OF
THE NEARING WESTERN TROUGH. THE VAIL OF PRECIP OVERHEAD MONDAY
MORNING WILL QUICKLY EXIT EAST DURING THE DAY MONDAY...WITH FREEZING
DRIZZLE AND/OR SNOW AT THE TAIL END. WARM AIR WILL CONTINUE TO PUSH
INTO THE AREA DURING THE DAY MONDAY...WITH 850MB TEMPS RISING TO
3-5C NEAR THE WI BORDER...AS SFC TEMPS JUMP ABOVE FREEZING /33-37F/.
EXPECT THE N END OF THE TROUGH ACROSS SASKATCHEWAN MONDAY TO CLOSE
OFF OVER CENTRAL MANITOBA MONDAY NIGHT...AND DEEPEN ACROSS ONTARIO
TUESDAY NIGHT...WITH THE TROUGH EXTENDING S FROM THE LOW ALL THE WAY
THROUGH TX. SOME UNCERTAINLY REMAIN IN THE MERGING OF THE N AND S
STREAM TROUGHS...WITH THE SFC REFLECTIONS OVER W ONTARIO AND NE KS
AT 06Z TUESDAY. THESE 2 SFC LOWS ARE EXPECTED TO MERGE NEAR THE CWA
TUESDAY MORNING INTO EARLY TUESDAY AFTERNOON...BEFORE QUICKLY
EJECTING NE TUESDAY AFTERNOON/EVENING. ANOTHER ROUND OF POSSIBLE
FREEZING RAIN/DRIZZLE WILL BE POSSIBLE LATE TUESDAY. S FLOW OFF LAKE
SUPERIOR AND ACROSS AREAS TO S MAY LEAD TO ANOTHER ROUGH OF FREEZING
DRIZZLE. AMOUNTS SHOULD REMAIN LIGHT...WITH ONLY A COUPLE HUNDREDTHS
ANTICIPATED AT THIS TIME...AS HIGHS WARM INTO THE MID TO UPPER 30S
TUESDAY AFTERNOON. MIN TEMPS TUESDAY WILL BE NEARLY IDENTICAL TO
HIGH TEMPS FORECAST FOR WEDNESDAY...DUE TO THE SLOW COOL DOWN
EXPECTED THROUGH THE DAY WEDNESDAY. WEDNESDAY COULD ALSO BE A BIT
BREEZY AS COLD AIR WRAPS AROUND THE EXITING LOW.
THE PROGRESSIVE 500MB LOW WILL CONTINUE TO DEEPEN NEAR JAMES BAY
WEDNESDAY NIGHT...WITH THE TROUGH ENCOMPASSING MUCH OF THE U.S. THIS
WILL BRING THE RETURN OF NW FLOW ALOFT...FROM LATE WEDNESDAY NIGHT
THROUGH THE REMAINDER OF THE FCST PERIOD. THE RESULT WILL BE SEVERAL
DIFFICULT TO TIME WAVES WILL PUSH ACROSS THE AREA FROM THURSDAY
THROUGH SATURDAY...AND BEYOND...AS WELL AS A RETURN TO NEAR OR BELOW
NORMAL TEMPERATURES. 850MB TEMPS WILL PLUMMET TO AROUND -20C
WEDNESDAY EVENING...AND CONTINUE TO FALL TO -22 TO -25C FROM
THURSDAY EVENING THROUGH FRIDAY. CONTINUED TO HIGHLIGHT THE W FACING
SLOPES OF W UPPER MI...AND AREAS E OF MUNISING NEAR LAKE SUPERIOR
FOR THE BEST CHANCE OF SNOW GIVEN THE NW WINDS. SFC-850MB WINDS
SHOULD BECOME MORE WESTERLY FRIDAY...SLOWLY PUSHING THE BEST CHANCE
OF CONTINUED LES N TO THE TIP OF THE KEWEENAW PENINSULA...AND JUST
OFFSHORE ACROSS E UPPER MI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1242 AM EST SUN JAN 27 2013
VFR CONDITIONS WILL CONTINUE AT ALL SITES THROUGH SUNDAY. BY SUNDAY
EVENING...NEXT SYSTEM STARTS TO AFFECT THE AREA AND WILL BRING IN
SOME MVFR VIS AND CIGS WITH SOME LIGHT SNOW. THERE COULD BE A BRIEF
PERIOD OF -SHSN OR FLURRIES AT KCMX/KSAW OVERNIGHT...BUT IT
SHOULDN/T AFFECT VISIBILITIES OVERNIGHT. THESE CLOUDS SHOULD PUSH
EAST ON SUNDAY MORNING AND JUST LEAVE SOME PASSING MID CLOUDS. DID
PUT A MENTION OF SCATTERED LOW CLOUDS AT KSAW TOMORROW
MORNING...SINCE THE MODELS ARE HINTING AT THAT POSSIBILITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EST SAT JAN 26 2013
HIGH PRESSURE CURRENTLY OVERHEAD WILL SHIFT EAST TONIGHT AND LEAD
TO INCREASING SOUTHERLY WINDS...BUT EXPECT GUSTS TO REMAIN BELOW
25KTS. WINDS WILL REMAIN BELOW 25KTS THROUGH THE FIRST COUPLE OF
DAYS OF THE UPCOMING WORK WEEK DUE TO WEAK PRESSURE GRADIENTS. A
LOW MOVING THROUGH THE GREAT LAKES ON TUESDAY AND THEN INCREASING
IN INTENSITY OVER EASTERN CANADA WILL PRODUCE INCREASING NORTHERLY
WINDS TO 30KTS TUESDAY NIGHT INTO WEDNESDAY. THIS...COMBINED WITH
COLDER AIR SURGING SOUTH...WILL LEAD TO FREEZING SPRAY FOR THE
MIDDLE AND END OF THE WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 1 PM EST
MONDAY FOR MIZ006-007-085.
WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
10 AM EST /9 AM CST/ MONDAY FOR MIZ005-010-011.
WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
11 AM EST /10 AM CST/ MONDAY FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 AM EST SUN JAN 27 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 421 PM EST SAT JAN 26 2013
LAKE EFFECT HAS BEEN GRADUALLY DIMINISHING THROUGH THE AFTERNOON
HOURS...AS THE NORTHERLY FLOW HAS SLOWED WITH HIGH PRESSURE MOVING
OVER THE CWA. STILL HAVE SOME LIGHT SNOW SHOWERS OVER THE NORTH
CENTRAL CWA...BUT EXPECT THEM TO END OR PUSH NORTH DURING THE LATE
AFTERNOON AND EARLY EVENING. OTHERWISE...A FAIRLY NICE AFTERNOON
WITH LIGHT WINDS AND TEMPERATURES AT OR SLIGHTLY BELOW NORMAL AS OF
3PM.
HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES WILL SHIFT EAST
TONIGHT AS THE UPPER RIDGE BUILDS NORTHEAST INTO THE UPPER
MISSISSIPPI VALLEY. AS THIS OCCURS...BROAD H800-600 WARM AIR
ADVECTION CURRENTLY IN MINNESOTA AND STARTING TO MOVE INTO WESTERN
LAKE SUPERIOR WILL CONTINUE EAST ACROSS THE CWA TONIGHT. SO FAR
TODAY...HAVE ONLY SEEN A FEW OBS REPORTING SNOW SHOWERS FROM THIS
MID CLOUD DECK IN NORTHERN MN...WHICH WAS LIKELY HELD OFF BY DRY
H925-850 AIR SEEN ON 12Z KINL SOUNDING AND RUC SOUNDINGS IN THAT
AREA. LATEST MODELS DO TRY TO MOISTEN THE CENTRAL CWA TOWARDS
MIDNIGHT...AS THE STRONGER H925-850 WAA SLIDES EAST ALONG THE WI
BORDER. NOT LIKING HOW QUICKLY THINGS MOISTEN...BUT WITH THE IDEA IN
SEVERAL MODELS...WILL ADD SLIGHT CHANCES THERE. WILL KEEP THE BEST
POPS OVER THE NORTHERN HALF OF LAKE SUPERIOR WHERE THE LOWER LEVELS
WERE A LITTLE MORE MOIST AND THE MID LEVEL WAA WAS THE STRONGEST.
ALSO ADDED A MENTION OF FLURRIES TO AREAS SURROUNDING THE POPS TO
ACCOUNT FOR SOME SNOW MAKING IT THROUGH THE DRY AIR.
THE OTHER ITEM OF CONCERN HEADING INTO THE OVERNIGHT HOURS WILL BE
THE INCREASED MOISTENING OF THE LOWER LEVELS OFF LAKE MICHIGAN. AS
THIS OCCURS...THE H850 TEMPS WILL BE WARMING TOWARDS -10C
OVERNIGHT...SO DON/T EXPECT LAKE ENHANCEMENT TO GET TOO OUT OF
HAND. BUT WITH THE SNOW ALOFT FEEDING INTO THE LOWER LEVELS FORCING
THAT IS MAINLY BELOW -10C...EXPECT SNOW TO DEVELOP THERE. H925 WINDS
ARE FAVORABLE FOR SOUTHERN LUCE AND SOUTHEAST SCHOOLCRAFT...SO HAVE
INCREASED POPS INTO LOW END LIKELY VALUES FOR THOSE LOCATIONS
AND TAPERED IT OFF FAIRLY QUICKLY TO THE WEST. WITH SNOW RATIOS ON
THE LOW END...AROUND 10-14 TO 1 INITIALLY AND TRENDING
TOWARDS 8-1 SUNDAY MORNING...EXPECT ACCUMULATIONS TO BE FAIRLY LIGHT
IN THOSE AREAS WITH ONLY AN INCH OF ACCUMULATION. THE LAKE EFFECT
SHOULD DIMINISH LATER SUNDAY MORNING INTO THE EARLY AFTERNOON DUE TO
THE CONTINUED WARMING OF TEMPS ALOFT SHOVING INVERSION HEIGHTS TO
3KFT.
SUNDAY LOOKS TO BE FAIRLY QUIET...AS THE AREA IS BETWEEN THE
EXITING WARM AIR ADVECTION PRECIPITATION AND THE NEXT APPROACHING
SYSTEM FOR SUNDAY NIGHT. THE NEXT WAVE IS CURRENTLY OVER
SOUTHERN CALIFORNIA AND QUICKLY MOVES NORTHEAST AND
TOWARDS THE AREA TONIGHT AND SUNDAY. WITH THE INCREASED CONSISTENCY
IN THE MODELS...HAVE DELAYED THE START OF THE PRECIPITATION UNTIL
00Z AND LATER. THE LONG TERM DISCUSSION WILL COVER THIS SYSTEM IN
FURTHER DETAILS.
OTHERWISE...WILL SEE A GAP IN THE CLOUDS BEHIND THE WAA
CLOUDS DEPARTING IN THE MORNING AND THE INCREASING CLOUDS FROM THE
SOUTHWEST IN THE AFTERNOON. THINK THIS CLEARING WILL BE MOST LIKELY
OVER THE WEST HALF AND HAVE TRENDED TOWARDS PARTLY-MOSTLY SUNNY SKY
FOR PERIOD AROUND MID DAY. FARTHER EAST...NAM/GFS ARE HINTING AT
SOME LOWER CLOUDS DEVELOPING TONIGHT AND REMAINING THROUGH MUCH OF
SUNDAY. NOT OVERLY CONFIDENT ON THIS SOLUTION WITH THE DRY AIR
UPSTREAM...BUT WITH THE EXITING MID CLOUDS AND APPROACHING HIGH
CLOUDS...A PARTLY-MOSTLY CLOUDY FORECAST SEEMED WARRANTED.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 421 PM EST SAT JAN 26 2013
EARLY PORTION OF THE LONG TERM PERIOD SHOULD BE FAIRLY ACTIVE AS
PATTERN UNDERGOES SIGNIFICANT TRANSITIONS NEXT WEEK. CURRENT ERN
NAMERICA TROF IS IN THE PROCESS OF WEAKENING...AND IT WILL LIFT OUT
OVER THE NEXT COUPLE OF DAYS AS A TROF AMPLIFYING OVER THE WRN CONUS
FORCES DOWNSTREAM RIDGING OVER THE ERN CONUS INTO SE CANADA. THIS
WILL LEAD TO A SUBSTANTIAL WARMUP FOR THE UPPER LAKES. AS THE WRN
TROF THEN SHIFTS E...IT APPEARS PATTERN WILL RETURN TO SOME FORM OF
THE RECENT PATTERN WITH WRN RIDGING/ERN TROFFING. THIS WILL SUPPORT
A TREND BACK TO BLO NORMAL TEMPS FOR THE LAST HALF OF THE WEEK AND A
RETURN OF PERSISTENT LES OFF LAKE SUPERIOR. WHILE IT DOESN`T HAPPEN
TOO OFTEN...CONFIDENCE IN THE LATTER PORTION OF THE LONG TERM IS
MUCH MUCH HIGHER THAN THE EARLY PART. DURING THE EARLY PART...THERE
REMAINS CONSIDERABLE UNCERTAINTY IN THE EVOLUTION OF THE WRN TROF
THRU THE CNTRL INTO ERN CONUS. THAT UNCERTAINTY CENTERS AROUND
WHETHER THE PIECE OF ENERGY IN THE SRN PART OF THE WRN TROF LIFTS
OUT AND PHASES WITH ENERGY DROPPING SE OUT OF CANADA. MORE ON THAT
LATER.
BEGINNING SUN NIGHT...ATTENTION WILL BE ON THE SHORTWAVE THAT IS
CURRENTLY LIFTING NE ACROSS AZ IN RESPONSE TO TROF THAT IS NOW
AMPLIFYING ALONG THE W COAST. WAVE LOOKS VERY WELL-DEFINED ON WATER
VAPOR IMAGERY WITH AN ASSOCIATED PLUME OF PACIFIC MOISTURE. AS
SHORTWAVE CONTINUES TO LIFT NE...MODELS SHOW A NICE SHALLOW STREAM
OF MOISTURE GETTING TAPPED OFF THE GULF. SO...WITH THE SHALLOW
MOISTURE FEED...WAA/ISENTROPIC ASCENT AHEAD OF WAVE WILL LEAD TO AN
AREA OF PCPN DEVELOPING ACROSS THE CNTRL PLAINS AND THEN EXPANDING
AS IT SHIFTS INTO THE GREAT LAKES. PRECIPITABLE WATER ALSO INCREASES
TO 200-300PCT OF NORMAL. SO IF FORCING IS STRONG...MAY SEE SOME
DECENT PCPN AMOUNTS. OVERALL...MODELS ARE TRENDING SLIGHTLY MORE
DEFINED WITH SHORTWAVE WHICH LOOKS ON TRACK GIVEN CURRENT WATER
VAPOR IMAGERY AND DESPITE THE FACT THAT IT WILL BE WEAKENING AS IT
LIFTS NE THRU THE BUILDING LARGER SCALE RIDGE. MODELS ARE ALSO
TRENDING A LITTLE FARTHER N AND W WITH ASSOCIATED PCPN. NAM/REGIONAL
GEM REPRESENT THE THE NW SIDE OF THE 12Z MODEL RUNS WITH BOTH
SPREADING PCPN SQUARELY ACROSS UPPER MI. NAM HAS AMOUNTS FROM
0.25-0.6 INCHES WHILE THE GEM HAS 0.15-0.3 INCHES. ALTHOUGH A LITTLE
SKEPTICAL OF THESE MORE NW SOLUTIONS...TRENDS FROM REMAINING
GUIDANCE STILL SUPPORT CONTINUING TREND FROM PREVIOUS FCST TO BUMP
UP POPS FOR SUN NIGHT. PER 295K SFC...A HEALTHY PUSH OF ISENTROPIC
ASCENT IS INDICATED TO SPREAD INTO THE GREAT LAKES REGION WHICH SHOULD
LEAD TO A DECENT AREA OF PCPN. PTYPE MAY BE AN ISSUE AS 850MB TEMPS
RISE TO AROUND 0C SUN. HOWEVER...WITH WETBULB PROFILE BLO 0C...SEEMS
LIKELY THAT TEMP PROFILE WILL QUICKLY FALL SUBZERO DUE TO
EVAPORATIVE COOLING AS WELL AS DYNAMIC COOLING. PLAN FOR NOW WILL BE
TO UTILIZE JUST SNOW AS PTYPE SUN NIGHT. 295K SFC SHOWS MIXING
RATIOS AROUND 4G/KG...SUGGESTING POTENTIAL FOR UP TO 8 INCHES OF
SNOW WHERE MAX ASCENT OCCURS. SINCE DURATION OF PCPN WILL PROBABLY
BE ON THE ORDER 9HRS...HIGH END SNOW TOTALS COULD REACH 6 INCHES IF
MAX FORCING DOES SPREAD INTO UPPER MI. WILL CONTINUE TO PAINT THE
HIGHER PCPN AMOUNTS OVER THE SE FCST AREA WHERE SNOW AMOUNTS OF 2 TO
4 INCHES WILL BE INCLUDED FOR THIS FCST. MAY SEE 1-2 INCHES NW. ON
THE BACKSIDE OF SNOW AREA...PCPN MAY TRANSITION TO SOME -FZDZ SW TO
NE MON MORNING AS MID LEVEL MOISTURE PULLS OUT. THERE SHOULD THEN BE
A TREND TO DRY WEATHER DURING THE DAY MON.
OVER THE LAST FEW DAYS...THE BIGGEST UNCERTAINTY HAS BEEN THE
TUE/WED TIME PERIOD DUE TO THE CONSIDERABLE SPREAD OF SOLUTIONS
REGARDING THE EASTWARD PROGRESSION/EVOLUTION OF THE CURRENTLY
AMPLIFYING WRN CONUS TROF. MAIN POINTS OF UNCERTAINTY INVOLVE
WHETHER THE ENERGY IN THE BASE OF THE WRN TROF DROPS OUT AND HANGS
BACK OVER THE SW...OR IF IT DOES NOT...WILL IT LIFT NE AND PHASE
WITH ENERGY DROPPING SE TOWARD THE GREAT LAKES. THE ECMWF HAD
SEVERAL RUNS FAVORING THE IDEA OF DROPPING THE ENERGY OUT. IT IS NOW
TRENDING BACK TO KEEPING THE SRN PORTION PROGRESSIVE...BUT IT DOES
NOT LIFT ENERGY NE TO PHASE WITH THE NRN PORTION IN THE GREAT LAKES
REGION. THE GFS HAS HAD THE MOST RUNS FAVORING PHASING OF ENERGY IN
THE VCNTY OF THE GREAT LAKES WITH THE GLOBAL GEM/UKMET ALSO
GENERALLY LEANING IN THAT DIRECTION ON MOST RUNS. AGAIN...AS IN
PREVIOUS DAYS...THERE ARE A FEW GFS ENSEMBLES THAT HAVE A DEEP STORM
MOVING NE THRU THE UPPER LAKES REGION. AT THIS POINT...GIVEN THE
SPREAD OF SOLUTIONS...PARTICULARLY WITH REGARD TO THE ALWAYS
UNCERTAIN PHASING OF STREAMS AND LOCATIONS OF SUCH OCCURRENCE...
THERE IS NOT ENOUGH CONFIDENCE TO REALLY TREND INHERITED FCST MUCH
IN ANY DIRECTION. SO...AS HAS BEEN THE CASE IN RECENT DAYS...BEST
PATH WILL CONTINUE TO BE TO USE A CONSENSUS OF RECENT MODEL RUNS
UNTIL THE DETAILS ARE SORTED OUT. GIVEN THE WARMTH PUSHING INTO THE
AREA OVER THE NEXT FEW DAYS...MIXED PCPN COULD BE AN ISSUE...AND FOR
THIS FCST ISSUANCE WILL KEEP A MENTION OF A MIX...RANGING FROM
MOSTLY RAIN FOR A TIME SE TO MAINLY SNOW NW. DEPENDING ON TRACK OF
SFC LOW AND WHETHER IT DEEPENS SUBSTANTIALLY...THERE COULD BE A
TRANSITION TO SIGNIFICANT SNOW/BLSN LATER TUE INTO WED NEAR LAKE
SUPERIOR WHERE LAKE ENHANCEMENT/LES WILL GET UNDERWAY. LAKE SUPERIOR
LES WILL THEN BE THE RULE WED THRU FRI AS ARCTIC AIR SETTLES OVER
THE AREA (850MB TEMPS FALL TO -20 TO -25C). UTILIZED CATEGORICAL
POPS FOR THE USUAL AREAS FAVORED BY NW WINDS WED THRU FRI GIVEN VERY
HIGH CONFIDENCE IN LES. CLIPPER TYPE SYSTEM ARRIVING SAT MAY RESULT
IN -SN SPREADING INTO AREAS AWAY FROM LES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1242 AM EST SUN JAN 27 2013
VFR CONDITIONS WILL CONTINUE AT ALL SITES THROUGH SUNDAY. BY SUNDAY
EVENING...NEXT SYSTEM STARTS TO AFFECT THE AREA AND WILL BRING IN
SOME MVFR VIS AND CIGS WITH SOME LIGHT SNOW. THERE COULD BE A BRIEF
PERIOD OF -SHSN OR FLURRIES AT KCMX/KSAW OVERNIGHT...BUT IT
SHOULDN/T AFFECT VISIBILITIES OVERNIGHT. THESE CLOUDS SHOULD PUSH
EAST ON SUNDAY MORNING AND JUST LEAVE SOME PASSING MID CLOUDS. DID
PUT A MENTION OF SCATTERED LOW CLOUDS AT KSAW TOMORROW
MORNING...SINCE THE MODELS ARE HINTING AT THAT POSSIBILITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EST SAT JAN 26 2013
HIGH PRESSURE CURRENTLY OVERHEAD WILL SHIFT EAST TONIGHT AND LEAD
TO INCREASING SOUTHERLY WINDS...BUT EXPECT GUSTS TO REMAIN BELOW
25KTS. WINDS WILL REMAIN BELOW 25KTS THROUGH THE FIRST COUPLE OF
DAYS OF THE UPCOMING WORK WEEK DUE TO WEAK PRESSURE GRADIENTS. A
LOW MOVING THROUGH THE GREAT LAKES ON TUESDAY AND THEN INCREASING
IN INTENSITY OVER EASTERN CANADA WILL PRODUCE INCREASING NORTHERLY
WINDS TO 30KTS TUESDAY NIGHT INTO WEDNESDAY. THIS...COMBINED WITH
COLDER AIR SURGING SOUTH...WILL LEAD TO FREEZING SPRAY FOR THE
MIDDLE AND END OF THE WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
544 PM CST MON JAN 28 2013
.UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION.../ISSUED AT 413 PM CST MON JAN 28 2013/
FIRST THE HEADLINES. STARTING WITH THE HRRR/RUC THEN THE REST OF
THE 12Z RUNS...MODELS BEGAN TO SHIFT HEAVY SNOW BAND FOR TONIGHT
FARTHER NORTHWEST...KEEPING THE BULK OF THE SNOW NW OF THE MPX
CWA. MAY STILL GET A COUPLE INCHES OF SNOW IN THE FAR NW CORNERS
OF TODD...DOUGLAS...AND STEVENS COUNTIES...SO WITH THAT ALONG WITH
MATCHING UP WITH WHAT NEIGHBORS WERE DOING...ISSUED A WINTER
WEATHER ADVISORY FOR THOSE THREE COUNTIES. AT THE OTHER END OF THE
CWA HAVE A FREEZING RAIN ADVISORY FOR NE 3 COUNTIES IN WI. NOT
THRILLED WITH DOING THIS ADVISORY...BUT TO MATCH UP WITH
NEIGHBORING OFFICES...INCLUDED THESE COUNTIES IN A FREEZING RAIN
ADVY. EVERYWHERE ELSE...DENSE FOG IS LOOKING LIKE ALL BUT A
CERTAINTY FOR TONIGHT...SO A NEW DENSE FOG ADVISORY HAS BEEN
HOISTED.
UPPER WAVE RESPONSIBLE FOR ALL OF THIS HEADLINE FUN IS A DEEP
THROUGH THAT CAN BE SEEN ACROSS THE ERN ROCKIES THIS
AFTERNOON...AND WILL SLIDE ACROSS THE CENTER OF THE CONUS THROUGH
WEDNESDAY. AT THIS SFC...A 996 MB LOW AT 3 PM WAS CENTERED OVER
ERN CO. FAIRLY GOOD CONSENSUS AMONGST GUIDANCE ON THIS LOW MOVING
TO NEAR THE SE TIP OF MN BY TUESDAY MORNING...THEN OFF TO ERN LAKE
SUPERIOR BY THE TUE AFTERNOON. SEEING AN IMPRESSIVE WARM FRONT
MOVING NORTH ACROSS THE PLAINS WITH THIS LOW...WITH TEMPS IN THE
LOWER 70S AND DEWPS IN THE LOWER 50S UP TO ALMOST THE IA BORDER.
FOR THE WEATHER TONIGHT...LEANED MOST TOWARD THE 12Z NAM FOR
TIMING PRECIP IN AND ACROSS THE AREA AS THIS IS A GOOD
CONTINUATION OF WHAT THE RAP HAS BEEN SHOWING. RIGHT NOW...SEEING
IMPRESSIVE FGEN BAND SETTING UP ACROSS NE SODAK INTO NW MN...AND
LOOKING AT RAP H7-H6 FGEN FORECAST...SHOULD SEE AN INTENSE BAND OF
SNOW SET UP FROM NEAR ABERDEEN UP TO DETROIT LAKES. WITHIN THE
CENTER OF THE BAND SHOULD SEE A GOOD 4 TO 6 INCHES OF SNOW. FOR
THE MPX AREA...FAR NW CORNERS OF OUR FAR NW COUNTIES SHOULD GET IN
ON THE SRN FRINGE OF THIS BAND...WITH A COUPLE OF INCHES OF SNOW
BEING POSSIBLE. FOR SNOW POTENTIAL IN THE WEST...WILL HAVE TO WHAT
HAPPENS WITH A SECONDARY SHORT WAVE THAT SNEAKS UP WEST OF THE SFC
LOW LATE TONIGHT INTO TUESDAY MORNING. THE GEM WAS THE MOST
BULLISH WITH THIS WAVE...BRING A QUICK 2-3 INCHES OF SNOW TO WRN
MN. DID NOT PUT MUCH STOCK IN IT...BUT NOTICING THAT TOWARD THE
END OF RECENT RAP RUNS IT HAS BEEN SHOWING THIS SECONDARY BAND
SNEAKING IN AS WELL...SO WILL NEED TO WATCH THIS OVERNIGHT TO SEE
IF THE WINTER WEATHER ADVISORY NEEDS TO BE PULLED SOUTH.
OUTSIDE OF THE NW CWA...SOUNDINGS SHOW WHATEVER HAPPENING TONIGHT
TO BE DRIZZLE OR LIGHT RAIN...WITH ATMO ABOVE ABOUT H8 BEING DRY...
AND LITTLE OR NO SATURATION BEING SEEN IN THE DENDRITIC GROWTH
ZONE. SHOULD SEE DZ/RA RAPIDLY SPREAD NORTH AFTER 00Z AS STRONG
LOW LEVEL THETA-E ADVECTION WORKS IN. AT THE NOSE OF THE LLJ...THE
RAP IS EVEN INDICATING SOME THUNDER BEING POSSIBLE IN THE EAU AREA
AROUND MIDNIGHT AS BEST LIS DROP TO AROUND -1. 18Z HRRR
REFLECTIVITY FORECAST LOOKS CONVECTIVE IN THIS AREA AS WELL. OF
COURSE WITH ALL OF THIS PRECIP THE KEY WILL BE SFC TEMPS. THE
ENTIRE CWA CURRENTLY SITS BETWEEN 32 AND 36 AND WITH CONTINUED
SOUTHEAST FLOW THROUGH THE NIGHT...DO NOT EXPECT THESE TO CHANGE
MUCH...IN FACT...TEMPERATURES MAY CONTINUE TO RISE RIGHT THROUGH
THE NIGHT ACROSS THE SE CWA. BECAUSE OF THESE MILD
TEMPERATURES...WAS NOT TOO INCLINED TO ISSUE A FREEZING RAIN ADVY
WITH IT BEING QUESTIONABLE IF TEMPS FALL BELOW FREEZING. IN
ADDITION...WITH P-TYPE MAINLY BEING DZ...NOT EXPECTING MANY IMPACTS
WITH DZ AND TEMPS IN THE 30S WITH ALREADY WET SFCS IN PLACE DUE TO
MELTING TODAY. MAKE IT DRY WITH TEMPS IN THE 20S...AND IT WOULD BE
A DIFFERENT STORY...BUT THAT IS NOT WHAT WE ARE DEALING WITH.
WHERE THE HIGHEST POTENTIAL FOR MEANINGFUL FZRA EXISTS WOULD BE IN
THE FAR NE CWA...WHERE THERE WILL BE THE POTENTIAL FOR RAIN THIS
EVENING ON THE NOSE OF THE LLJ.
AS FOR THE FOG...THERE IS NOTHING BUT A SEA OF DENSE FOG FROM SRN
MN DOWN ACROSS IA AND ERN NEB. THIS WILL ADVECT RIGHT BACK NORTH
THIS EVENING...WITH WIDESPREAD FOG EXPECTED AGAIN...AS SEEN WITH
THE GRIDDED LAMP...HRRR...AND WRF-NMM. FOG SHOULD IMPROVE LATE
TONIGHT FROM WEST TO EAST AS AN INVERTED TROUGH/COLD FRONT WORKS
ACROSS MN. FOR SIMPLICITY SAKE...RAN THE FOG ADVY THROUGH 10 AM
TUESDAY MORNING EVERYWHERE...BUT CONDITIONS SHOULD IMPROVE
EARLIER THAN THAT IN WRN MN.
PRECIPITATION SHOULD MOSTLY COME TO AN END BY TUESDAY AFTERNOON
ACROSS THE AREA AS DRY ARCTIC HIGH BEGINS BUILDING IN. STILL SOME
DISAGREEMENT WITH PRECIP POTENTIAL TUESDAY NIGHT AS ANOTHER SFC
LOW RIPPLES NORTH ALONG THE FRONT FROM THE TULSA AREA UP TO MID
MICHIGAN. HUNG SOME CHANCE POPS BACK ACROSS ERN AREA TO ACCOUNT
FOR THE OFF CHANCE THAT SOME SNOW DEVELOPS WEST OF THE LOW. NOT ALL
THAT EXCITED ABOUT SNOW POTENTIAL ON THE BACK SIDE OF THIS SYSTEM
TUESDAY NIGHT INTO WEDNESDAY DUE TO THE FACT THAT UPPER FLOW WILL
BE NEARLY PARALLEL TO THE FRONTAL BOUNDARY. THIS WILL LIKELY KEEP
A COLD CONVEYOR BELT FROM DEVELOPING TO THE NORTH AND NORTHWEST OF
THE LOW AS IT WORKS UP ALONG THE FRONT...WITH MOST ACTIVITY STAYING
NEAR THE FRONT...AND NOT WORKING BACK TOWARD THE EAU AREA.
OF COURSE THE BIG STORY FOR WEDNESDAY THROUGH FRIDAY WILL BE THE
ARRIVAL OF ANOTHER SIGNIFICANT CHUNK OF ARCTIC AIR. TEMPERATURES
WILL BE NEARLY STEADY OR FALLING MUCH OF WEDNESDAY AFTERNOON...AND
BY WEDNESDAY NIGHT...THE COMBO OF TEMPS FALLING TO BELOW ZERO ON
15 TO 25 MPH NW WINDS WILL BRING BACK THE NEED FOR WIND CHILL
ADVISORIES FROM WEDNESDAY NIGHT RIGHT INTO FRIDAY MORNING.
AFTER FRIDAY...TEMPERATURES WILL MODERATE BACK CLOSER TO AND EVEN A
LITTLE ABOVE NORMAL BY THE END OF THE WEEKEND. STILL SEEING THE
POTENTIAL FOR A CLIPPER FRI NIGHT/SATURDAY ON THE ECMWF/GEM...WITH
A COUPLE OF INCHES OF SNOW BEING POSSIBLE ALONG AND NORTH OF I-94.
&&
.AVIATION.../00Z TAF ISSUANCE/
IFR OR LIFR CONDITIONS ARE EXPECTED THROUGH MOST OF TUESDAY
MORNING. THE MAIN FORECAST UNCERTAINTIES CONTINUE TO BE
PRECIPITATION TYPE. MOST STATIONS ARE AT OR SLIGHTLY ABOVE
FREEZING WHICH SHOULD CONTINUE FOR MUCH OF THE NIGHT IN THE LIGHT
SOUTHEAST FLOW. NOT OVERLY CONCERNED WITH FZDZ OR FZRA DUE TO THE
MOIST AIRMASS WHICH LIMITS ICE ACCRETION AT THESE MARGINAL
TEMPERATURES. WITH TIME...A BAND OF SNOW IS EXPECTED TO DEVELOP
ACROSS WEST CENTRAL MN AND THE BULK OF IT SHOULD REMAIN JUST WEST
OF AXN. AS LOW PRESSURE TRACKS NORTHEAST INTO WISCONSIN TUESDAY
MORNING...DRIER AIR WILL BEGIN TO WORK IN WITH IMPROVING
CONDITIONS. THIS COULD ALSO BRING A BETTER CHANCE FOR -SN OR FZDZ
FURTHER EAST.
KMSP...LIFR CONDITIONS EXPECTED THROUGH TUESDAY MORNING WITH A
GRADUAL IMPROVEMENT TO MVFR TUESDAY AFTERNOON. PRECIP SHOULD
REMAIN IN LIQUID FORM...BUT WILL NEED TO WATCH TEMPERATURES
CLOSELY FOR POTENTIAL FOR FZDZ LATE TONIGHT. BETTER CHANCE OF SUCH
PRECIP WILL ARRIVE MID MORNING TUESDAY AS COLDER AND DRIER AIR
BEGINS TO WORK IN FROM THE NORTH/NORTHWEST.
/OUTLOOK FOR KMSP/
WED...MVFR WITH POSSIBLE --SN. WIND NW 15-20G30KT.
THU...VFR WITH POSSIBLE MVFR CIGS. WIND NW 10-15G20KT.
FRI...VFR WITH POSSIBLE MVFR CIGS. LGT/VRB WIND.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-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-SWIFT-WASECA-WASHINGTON-WATONWAN-
WRIGHT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR DOUGLAS-
STEVENS-TODD.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR DUNN-EAU CLAIRE-
PEPIN-PIERCE-POLK-ST. CROIX.
FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST TUESDAY
FOR BARRON-CHIPPEWA-RUSK.
&&
$$
MPG/BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
413 PM CST SUN JAN 27 2013
.DISCUSSION...
QUITE THE INTERESTING SYSTEM UNFOLDING ACROSS THE AREA TODAY WITH
INTENSE BAND OF SNOW WORKING ACROSS THE AREA THIS AFTERNOON WITHIN
A STRONG ZONE OF FGEN IN THE H7-H6 LAYER. AS THIS STRONGER AND
MORE PERSISTENT LIFT MOVED NORTH...THE AS ADVERTISED COLLAPSING OF
THE WARM NOSE BACK BELOW FREEZING ALLOWED THE EARLY INITIAL PUSH
OF FZRA/PL TO QUICKLY TRANSITION TO SNOW...AND QUITE THE
IMPRESSIVE SNOW IT HAS BEEN. WITHIN THE MAIN BAND OF SNOW...RATES
OF 1-2 INCHES PER HOUR HAVE BEEN QUITE COMMON. HERE AT THE OFFICE
IN CHANHASSEN...WE GOT ABOUT 2.5 INCHES OF BETWEEN ABOUT 130 AND
330. THAT WOULD BE MORE SNOW IN 2 HOURS THAN WE HAVE SEEN IN THE
REST OF THE MONTH COMBINED!
THIS BAND OF SNOW WILL BE QUICKLY MOVING EAST WITH THE FGEN...WITH
THE RAP SHOWING THE HEAVY SNOW SHOULD BE ALL BUT DONE IN THE TWIN
CITIES BY 00Z...WITH IT NOT LASTING MUCH PAST 3Z IN THE LADYSMITH
AREA. CURRENT GRIDS MAY NOT BE FAST ENOUGH IN CLEARING PRECIP OUT
THIS EVENING...BUT THAT CAN BE UPDATED THROUGH THE EVENING. WHAT
WILL BE TRICKY THOUGH...IS THAT AS THE MAIN PRECIP BATCH MOVES
THROUGH...HAVE SEEN EXTENSIVE DZ/FG REPORTS ACROSS ERN NEB AND IA
THAT WILL BE MOVING UP HERE THIS EVENING AND DO EXPECT A 2-4 HR
WINDOW OF FZDZ BEHIND THE MAIN PRECIP BEFORE WE ARE LEFT WITH WHAT
LOOKS TO BE A RATHER FOGGY NIGHT...WITH A DENSE FOG ADVY POSSIBLY
IN THE BOOKS...THOUGH WILL WAIT UNTIL WINTER WEATHER HEADLINES ARE
PULLED DOWN BEFORE ISSUING ANY DENSE FOG ADVISORIES. AS FOR THOSE
WINTER WEATHER HEADLINES...ONLY CHANGE WAS TO TRIM A FEW COUNTIES
OFF THE ADVY ON THE NW END WHERE PRECIP FAILED TO REACH AND MNDOT
CONTINUES TO ADVERTISE GOOD TRAVEL CONDITIONS. DOUBT WE WILL HIT
WINTER STORM WARNING CRITERIA FOR ANY ONE SPECIFIC TYPE OF
PRECIPITATION /0.25 INCH OF FZRA AND 6 INCHES OF SNOW/...BUT THE
COMBO OF A TENTH OF AN INCH OF FZRA BEING TOPPED WITH 3 TO 5
INCHES OF SNOW WARRANTS KEEPING THE WARNING GOING...THOUGH WOULD
SUSPECT IT CAN BE PULLED BEFORE 6Z.
WILL GET A BREAK IN THE PRECIP MOST OF THE DAY MONDAY...BEFORE THE
MAIN TROUGH CURRENTLY ACROSS THE ROCKIES BEGINS PROGRESSING ACROSS
THE PLAINS. WHAT WILL MAKE THIS PRECIP EVENT DIFFICULT FROM THE
P-TYPE PERSPECTIVE IS THAT AS TODAYS PRECIP MOVES OUT...THE WARM
NOSE WILL MOVE BACK IN...WITH ANOTHER MELTING LAYER IN PLACE
MONDAY AFTERNOON AS THIS NEXT SYSTEM MOVES IN. MAIN SFC LOW IS
FORECAST TO GO FROM NW KS MONDAY AFTERNOON TO THE U.P. OF MICH BY
TUESDAY AFTERNOON. ALL MODELS SHOWING TWO BATCHES OF PRECIP WITH
THIS SYSTEM. LLJ WARM SECTOR PRECIP LOOKS TO STAY WELL SE OF THE
AREA...WHILE ANOTHER INTENSE BAND OF FGEN INDUCED SNOW MOVES
ACROSS WRN INTO NE MN. WITH THIS SIGNAL...UPPED POPS TO THE
CATEGORICAL RANGE IN THE NW CWA MONDAY NIGHT...WITH 2-3 INCHES OF
SNOW UP IN THE MORRIS/ALEX AREA. CONFIDENCE ON PRECIP OCCURRENCE
ACROSS THE REST OF THE AREA IS A BIT LOWER AS THESE TWO BATCHES OF
PRECIP SPLIT THE AREA...BUT WHATEVER HAPPENS MONDAY NIGHT WITH
PRECIP IN THE ERN 2/3RDS OF THE CWA...FORECAST SOUNDINGS AGAIN SAY
THE P-TYPE WILL BE RA OR FZRA DEPENDING ON THE SFC TEMP.
AFTER NEARLY STEADY TEMPERATURES TODAY THROUGH TUESDAY...THE
ENCROACHMENT OF ANOTHER ARCTIC HIGH FOR THE END OF THE WEEK WILL
LEAD TO A SIGNIFICANT COOL DOWN STARTING TUESDAY NIGHT. WILL SEE
STRONG CAA ALL DAY WEDNESDAY RIGHT THROUGH WEDNESDAY NIGHT AS HIGH
PRESSURE GOES FROM THE DAKOTAS OVER TO THE KANSAS CITY AREA BY
FRIDAY MORNING. WILL SEE ANOTHER HEALTHY SURGE OF COLD BEHIND THIS
SYSTEM...WITH H85 TEMPS BY THURSDAY AGAIN BACK BETWEEN 25 C AND
30 C BELOW ZERO. THIS WILL GIVE MUCH OF THE MN CWA ANOTHER SHOT AT
SEEING SUB ZERO HIGHS THURSDAY AFTERNOON.
FOR FRIDAY THROUGH THE WEEKEND...A MODERATION IN TEMPERATURES IS
EXPECTED AS A CLIPPER SLIDES ACROSS NRN MN AND WI FRI
NIGHT/SATURDAY. MAY SEE A QUICK 1-2 INCHES OF SNOW OUT OF THIS
WITH CURRENT INDICATIONS BEING THAT THE BEST CHANCE FOR
ACCUMULATING SNOW WILL BE NORTH OF I-94.
&&
.AVIATION.../18Z TAF ISSUANCE/
AREA OF -FZRAPL LIFTING NORTH/NORTHEAST AROUND 20 KNOTS PER RADAR
TRENDS. THIS WILL WORK INTO ALL BUT PERHAPS KAXN BY LATE
AFTERNOON. WILL CONTINUE TO MONITOR TRENDS. MODELS CONTINUE TO
TREND TOWARD IFR/LIFR TO SNOW AFTER 20Z-21Z ACROSS MOST OF TAF
SITES. HAVE INCLUDED THIS TREND AS WELL. LOOK FOR 3-5 INCHES SNOW
ACCUMULATION NEAR KEAU WITH PERHAPS A COUPLE INCHES OF SNOW AND ONE
TENTH INCH OF ICE OVER EAST CENTRAL MN. THE WINTRY MIX WILL END
THIS EVENING WITH FOG AND PERHAPS FREEZING DRIZZLE COMMON DURING
THE OVERNIGHT HOURS. WILL TREND SLOW IMPROVEMENT INTO MONDAY
MORNING WITH PERHAPS LOW END MVFR INTO THE AFTERNOON. SOUTHEAST
WINDS 10 KNOTS OR LESS MOST PLACES INTO TONIGHT BECOMING VARIABLE
AND EVENTUALLY LIGHT SOUTHWEST TO WEST INTO MONDAY.
KMSP...LIGHT FREEZING RAIN AND SLEET EXPECTED FOR A COUPLE HOURS
OR SO...TRENDING TO SNOW THIS AFTERNOON INTO THE EARLY
EVENING...PERHAPS ENDING AS FREEZING DRIZZLE OVERNIGHT. CEILINGS
DROP TO IFR PERHAPS LIFR INTO TONIGHT AS SYSTEM MOVES THROUGH WITH
VSBYS REMAINING AT LEAST MVFR THROUGH THE NIGHT INTO MONDAY
MORNING. SLOW IMPROVEMENT TO LOW END MVFR INTO AFTERNOON.
/OUTLOOK FOR KMSP/
MONDAY...IFR CIGS EARLY TRENDING MVFR CIGS/VSBYS IN THE AFTERNOON.
S WIND 5 KTS. MONDAY NIGHT...MVFR CIGS EXPECTED. IFR CIGS AND MVFR
VSBYS POSSIBLE. CHANCE OF RAIN AND SNOW. WIND LIGHT AND VARIABLE.
TUESDAY...MVFR CIGS/VSBYS EXPECTED. IFR CONDITIONS POSSIBLE.
CHANCE OF SNOW. W WIND 5 TO 10 KTS. TUESDAY NIGHT...MVFR CIGS
POSSIBLE EARLY. CHANCE OF SNOW EARLY. NW WIND 10 TO 20 KT.
WEDNESDAY...VFR CONDITIONS EXPECTED. NW WIND 15 TO 25 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-
BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-HENNEPIN-ISANTI-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-
NICOLLET-RAMSEY-REDWOOD-RENVILLE-SCOTT-SHERBURNE-SIBLEY-
WATONWAN-WRIGHT-YELLOW MEDICINE.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR DAKOTA-
FARIBAULT-FREEBORN-GOODHUE-RICE-STEELE-WASECA-WASHINGTON.
WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR POLK.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-RUSK-ST. CROIX.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1149 PM CST SAT JAN 26 2013
.UPDATE...
ISSUED AT 845 PM CST SAT JAN 26 2013
OVER THE LAST FEW HOURS AREA OF OVERRUNNING RAIN HAS DEVELOPED
FROM SOUTHERN KANSAS INTO N OK. THIS AREA SHOULD CONTINUE TO
EXPAND INTO OUR CWA DURING THE PREDAWN HOURS AND EARLY SUNDAY
AS ZONE OF ISENTROPIC LIFT STRENGTHENS AND EXPANDS NORTHEAST WITH
INTENSIFYING LOW LEVEL JET.
OVERALL...GOING FORECAST IS LOOKING EXCELLENT. BASED ON REGIONAL RADAR
TRENDS AND LATEST HRRR AND NAM WE MAY BE BRINGING THE PRECIP INTO
OUR AREA A BIT TOO FAST BUT IT WOULD APPEAR THAT DIFFERENCE WOULD
ONLY BE ON THE ORDER OF AN HOUR OR TWO...AND HAVE MADE THIS VERY
SUBTLE TWEEK TO HOURLY POP GRIDS FROM COU NORTH AT 06Z. GOING
FORECAST FOR FREEZING LINE AT THE SURFACE IS ALSO STRONGLY
SUPPORTED BY LATEST HI-RES GUIDANCE. WHILE ITS CERTAINLY POSSIBLE
THAT SOME MINOR TWEEKS WILL BE REQUIRED ONCE RAIN AND SURFACE TEMP
TRENDS BECOME A BIT MORE OBVIOUS DONT THINK I CAN IMPROVE UPON ANY
OF THESE AT THIS TIME. GOING ADVISORY CERTAINLY DOES A NICE JOB
OF HIGHLIGHTING GREATEST FREEZING RAIN THREAT IN OUR CWA.
TRUETT
&&
.SHORT TERM...
ISSUED AT 330 PM CST SAT JAN 26 2013
(TONIGHT AND SUNDAY)
MAIN ITEM OF INTEREST FOR THE NEXT 24 HOURS IS THE POTENTIAL FOR
FREEZING RAIN AND ICE ACCUMULATIONS.
THE PATTERN WILL BE PROGRESSIVE DURING THIS PERIOD AS AN UPPER
TROF DIGS ALONG THE WEST COAST KICKING THE SOUTHWEST UPPER TROF
NEWD INTO THE PLAINS TONIGHT AND THEN INTO THE UPPER MS VALLEY ON
SUNDAY. IN THE PROCESS THE UPPER RIDGE CURRENTLY CENTERED THRU THE
WRN PLAINS WILL SHIFT TO A POSITION INVOF THE MS RIVER BY 12Z
SUNDAY AND THEN INTO THE OH VALLEY BY SUNDAY EVENING. IN THE
PROCESS...THE SURFACE HIGH NOW CENTERED THRU IL WILL RETREAT EWD
WITH A SWLY LLJ AND LOW LEVEL WAA COMMENCING IN ITS WAKE. THIS
VEERING LOW LEVEL JET IS FORECAST TO TRANSPORT WARM MOIST AIR
BACK INTO THE AREA OVERNIGHT INTO SUNDAY MORNING AND PROVIDE
ASCENT FOR A PRECIPITATION EVENT. A FAIRLY EXTENSIVE SHIELD OF
PRECIPITATION IS EXPECTED TO DEVELOP OVERNIGHT IN RESPONSE. THE
MODELS ARE IN GENERAL AGREEMENT ON THE SCENARIO BUT IN ARE
TRENDING A BIT SLOWER WITH THE ONSET OF RAIN. GIVEN THE UPPER RIDGE
AXIS ALONG THE MS RIVER AT DAYBREAK SUNDAY...THE THREAT OF RAIN
SHOULD REMAIN TO THE WEST OF THE MS RIVER TONIGHT...SPREADING EAST
ON SUNDAY MORNING WITH PROGRESSION OF THE PATTERN. THERE WILL BE A
BATTLE DURING THE EVENT BETWEEN THE ARRIVAL OF WARM/ABOVE FREEZING
AIR AND THE ONSET AND SPREAD OF RAINFALL. COMPLICATING THIS IS THE
LOWER SURFACE DEW POINTS WILL RESULT IN EVAPORATIVE COOLING WHICH
MAY INITIALLY OFFSET THE WARMING...HOWEVER GIVEN THE STRENGTH OF
WARMING...THE WARM AIR WILL OVERWHELM THE RESIDUAL COLD AIR ON THE
BACKSIDE OF THE RETREATING HIGH ACROSS ERN MO AND WEST CENTRAL IL.
TEMPS IN MID MO MAY BE ABOVE FREEZING BY THE TIME THE RAIN BEGINS
LATE TONIGHT AND IN THE ST LOUIS AREA THEY WILL BE FLIRTING WITH
THE FREEZING MARK FOR SEVERAL HOURS NEAR THE ONSET. THE COLD AIR
WILL BE STRONGER AND REMAIN ENTRENCHED LONGER IN NE MO AND WEST
CENTRAL IL WHERE ICE ACCUMULATIONS WILL AVERAGE .10 TO .15 INCHES.
I HAVE EXPANDED THE FREEZING RAIN A BIT FURTHER SOUTH WHERE THERE
COULD BE SOME DECENT GLAZING. BY EARLY AFTERNOON WARM AIR WILL
COMPLETELY OVERSPREAD THE REGION WITH TEMPS SOARING.
GLASS
&&
.LONG TERM...
ISSUED AT 330 PM CST SAT JAN 26 2013
(SUNDAY NIGHT THROUGH TUESDAY NIGHT)
THE WARM SECTOR WILL COMPLETELY OVERSPREAD THE AREA SUNDAY NIGHT
AS SOUTHERLY LOW LEVEL FLOW TRANSPORTS WARM AIR AND MOISTURE NEWD.
THIS WILL RESULT IN A PERIOD OF WELL ABOVE NORMAL TEMPERATURES
THROUGH TUESDAY AND MOST LIKELY SOME RECORDS WILL BE SET. THE SWLY
FLOW ALOFT IS LARGELY VOID OF ANY WELL-DEFINED DISTURBANCES TO
CONTRIBUTE TO LARGE SCALE ASCENT THROUGH MONDAY NIGHT. THUS ANY
PRECIPITATION THREAT WILL INITIALLY BE LIGHT RAIN/DRIZZLE ON
SUNDAY NIGHT WITH THE MOISTURE RETURN AND THEN SCATTERED SHOWERS
OR THUNDERSTORMS WITH THE SWLY LLJ AXIS. PROGRESSION OF THE WRN
U.S. LARGE SCALE POSITIVELY TILTED UPPER TROF INTO THE CENTRAL
CONUS AND THE PASSAGE OF THE ASSOCIATED SURFACE COLD FRONT ON
TUESDAY AND TUESDAY NIGHT SHOULD LEAD TO THE WIDESPREAD SHOWERS
AND THUNDERSTORMS. SEVERE POTENTIAL WILL ULTIMATELY DEPEND ON THE
AMOUNT OF INSTABILITY AS DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT ORGANIZED CONVECTION.
(WEDNESDAY THROUGH SATURDAY)
A DEEP LONGWAVE TROF WILL EVOLVE THRU THE ERN HALF OF THE CONUS
DURING THIS PERIOD. THE COLD FRONT ON TUESDAY/TUESDAY NIGHT WILL
BRING AN INITIAL SURGE OF COLD AIR...WITH A BIG PUSH OF ARCTIC AIR
ON THURSDAY. FRIDAY APPEARS TO BE THE COLDEST DAY WITH WELL BELOW
NORMAL TEMPERATURES...THEN THE ARCTIC RETREATS BY THE WEEKEND WITH
WAA UNDERWAY AND WARMING TEMPS.
GLASS
&&
.AVIATION...
ISSUED AT 1147 PM CST SAT JAN 26 2013
RAIN HAS DEVELOPED OVER KANSAS AND IS SLOWLY MAKING ITS WAY TO THE
EAST AND NORTHEAST. LITTLE ADJUSTMENTS TO TIMING OF ONSET OF THE
RAIN...WITH IT MOVING INTO KCOU BY 10Z...KSUS BY 12Z AND REST OF
TAF SITES AROUND 13Z. STILL EXPECT IT TO BE ALL RAIN AT KCOU...BUT
START OFF AS FZRA IN METRO AREA AND KUIN. TEMPS TO RISE ABOVE
FREEZING BY 16Z...WHILE KUIN WILL NOT WARM UP TIL AROUND 18Z. 00Z
MODEL RUNS KEEPING RAIN AROUND A BIT LONGER...SO WILL NOT SEE
RAIN MOVE OUT OF KCOU TIL 19Z...METRO AREA TIL 22Z AND KUIN TIL
01Z MONDAY. AS FOR CIGS...TO DROP DOWN TO MVFR WHEN RAIN MOVES IN
AND REMAIN MVFR FOR REST OF FORECAST PERIOD. EAST TO SOUTHEAST
WINDS TO PERSIST THEN VEER TO THE SOUTH AND PICKUP AS WARM FRONT
LIFTS NORTH OF TAF SITES. HAVE ADDED GUSTS NEAR 25KTS FOR KCOU AND
KUIN FOR THIS AFTERNOON AS DECENT WINDS MIX DOWN TO THE SURFACE.
SOME CONCERN ABOUT LLWS TONIGHT AFTER 00Z MON OVER CENTRAL AND
NORTHEAST MO DUE TO DECENT LL JET...BUT CONFIDENCE IS LOW AND WILL
LEAVE OUT OF TAFS FOR NOW.
SPECIFICS FOR KSTL...RAIN HAS DEVELOPED OVER KANSAS AND IS SLOWLY
MAKING ITS WAY TO THE EAST AND NORTHEAST. LITTLE ADJUSTMENTS TO
TIMING OF ONSET OF THE RAIN...WITH IT MOVING INTO METRO AREA
BETWEEN 12Z AND 13Z. STILL EXPECT IT TO START OFF AS FZRA IN
METRO AREA WITH LIGHT ICE ACCUMULATION...BUT TEMPS TO RISE ABOVE
FREEZING BY 16Z. 00Z MODEL RUNS KEEPING RAIN AROUND A BIT
LONGER...SO WILL NOT SEE RAIN MOVE OUT OF METRO AREA TIL 22Z. AS
FOR CIGS...TO DROP DOWN TO MVFR WHEN RAIN MOVES IN AND REMAIN MVFR
FOR REST OF FORECAST PERIOD. EAST TO SOUTHEAST WINDS TO PERSIST
THEN VEER TO THE SOUTH AND PICKUP AS WARM FRONT LIFTS NORTH OF
KSTL BY 16Z.
BYRD
&&
.CLIMATE...
ISSUED AT 334 PM CST THU JAN 24 2013
RECORD OR NEAR RECORD-BREAKING TEMPERATURES MAY BE POSSIBLE ON
MONDAY AND TUESDAY. BELOW IS A TABLE OF RECORD HIGHS AND RECORD
HIGH MINIMUMS FOR ARE THREE OFFICIAL CLIMATE STATIONS: ST. LOUIS
(STL)...COLUMBIA (COU)...AND QUINCY (UIN):
ST. LOUIS
HIGH HIGH MINIMUM
1/2876 (1970)53 (1914)
1/2973 (2008)44 (1947)
COLUMBIA
HIGH HIGH MINIMUM
1/28 67 (2002) 53 (1914)
1/29 64 (2008) 44 (1938)
QUINCY
HIGH HIGH MINIMUM
1/28 63 (1914) 46 (1914)
1/29 63 (1914) 38 (1989)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM CST SUNDAY FOR KNOX MO-
MONROE MO-SHELBY MO.
FREEZING RAIN ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR LEWIS MO-
LINCOLN MO-MARION MO-PIKE MO-RALLS MO.
IL...FREEZING RAIN ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR ADAMS IL-
BROWN IL-CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-
MONTGOMERY IL-PIKE IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1252 PM CST SUN JAN 27 2013
.UPDATE...
SENT AN UPDATE AT NOON TO EXPIRE MUCH OF THE DENSE FOG ADVISORY.
IT HAS BEEN EXTENDED FOR THE TRI-CITIES AND SURROUNDING AREAS.
VSBYS CONTINUE TO IMPROVE WITH HSI BEING THE ONLY HOLD-OUT BELOW
1/4 MILE.
BECAUSE OF ABOVE NORMAL CONFIDENCE...WE ARE CONTEMPLATING ISSUING
A DENSE FOG ADVISORY /FOR 10 PM TNGT TO NOON MON/ WITH THE 4 PM
PACKAGE. ALL OF OUR NEB COUNTIES FOR SURE. STILL UNSURE ABOUT OUR
N-CNTRL KS COUNTIES.
WILL INCLUDE THE SCIENTIFIC REASONING WITH THE LATE AFTN AFD.
&&
.PREV DISCUSSION... /ISSUED 1144 AM CST SUN JAN 27 2013/
AVIATION.../18Z GRI TAF THROUGH 18Z MONDAY AFTERNOON/
THIS AFTN: VLIFR CONDITIONS IN FOG EXPECTED TO GRADUALLY IMPROVE TO
IFR BY 20Z AND MVFR BY 22Z. WE/RE SEEING THE W EDGE OF THE STRATUS
ERODING JUST W OF BBW. SE WINDS BELOW 10 KTS SHIFTING TO SW.
TNGT: WITH STRATUS ERODING LATE IN THE DAY...THE LOW-LEVELS WILL
REMAIN CLOSE TO SATURATION. SO EXPECT ANY PERIOD OF VFR TO QUICKLY
DECAY TO MVFR BY 03Z WITH FURTHER DEGRADATION TO VLIFR IN DENSE
FOG. WINDS BECOME LIGHT AND VARIABLE.
MON THRU 18Z: VLIFR REMAINS A PROBLEM FOR AIR TRAVEL THRU 18Z.
EXPECT DENSE FOG CONTINUES THRU MIDDAY WITH GRADUAL IMPROVEMENT
AFTER 18Z. WINDS LIGHT AND VARIABLE.
CIG/VSBY CONFIDENCE: HIGH IN OCCURRENCE OF IFR
LOW IN TIMING OF IMPROVEMENT THIS AFTN
WIND CONFIDENCE: HIGH
WX CONFIDENCE: HIGH
PREV DISCUSSION... /ISSUED 1037 AM CST SUN JAN 27 2013/
1037 AM UPDATE... HAVE DROPPED OUR KS COUNTIES FROM THE ADVISORY
SINCE VIS SATL SHOWS A PERIOD OF CLEARING. ANOTHER AREA OF STRATUS
IS MOVING INTO PHILLIPS COUNTY AND WILL BE MOVING INTO ROOKS
COUNTY WITHIN THE HOUR. UNSURE HOW THIS EVOLVES BUT IT COULD PUT A
DAMPER ON OUR FCST HIGH TEMPS. AS WE MENTIONED YESTERDAY...THERE
IS ROOM FOR CONSIDERABLE BUST POTENTIAL IN TEMPS NEAR THE BOUNDARY
OF OVC VS CLR.
IN COORDINATION WITH LBF...HAVE EXTENDED MENTION OF PATCHY FOG
12PM-3PM AS A BUFFER FROM THE WIDESPREAD DENSE FOG MENTION WHICH
ENDS AT NOON.
HAVE ALSO LOWERED HOURLY TEMPS N OF I-80 FOR THE NEXT 3 HRS. WE
ARE SEEING BREAK IN THE OVC /BINOVC/ JUST NW OF BBW AND LBF. SO
THIS SHOULD ALLOW FOR SOME INCREASE IN TEMPS AS THE DAY
PROGRESSES.
HAVE MADE SOME HOURLY ADJUSTMENTS TO SKY FCST THRU 00Z. ALL
UPDATED PRODUCTS ARE OUT AND PUBLISHED TO THE WEB.
PREV DISCUSSION... /ISSUED 847 AM CST SUN JAN 27 2013/
846 AM UPDATE...VISIBILITIES CONTINUE TO DECAY. SO ISSUED A DENSE
FOG ADVISORY UNTIL NOON. FOG WILL LINGER IN SOME AREAS PAST
NOON...BUT VSBYS WILL IMPROVE TO MORE THAN A QUARTER MILE.
NPW/ZFP ARE OUT. HWO/EHWO WILL POST SHORTLY.
PREV DISCUSSION... /ISSUED 449 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
LONG TERM...WEDNESDAY THROUGH SATURDAY. OVERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NEZ039-040-
046>048-061>064-074>077-084>086.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1144 AM CST SUN JAN 27 2013
.AVIATION.../18Z GRI TAF THROUGH 18Z MONDAY AFTERNOON/
THIS AFTN: VLIFR CONDITIONS IN FOG EXPECTED TO GRADUALLY IMPROVE TO
IFR BY 20Z AND MVFR BY 22Z. WE/RE SEEING THE W EDGE OF THE STRATUS
ERODING JUST W OF BBW. SE WINDS BELOW 10 KTS SHIFTING TO SW.
TNGT: WITH STRATUS ERODING LATE IN THE DAY...THE LOW-LEVELS WILL
REMAIN CLOSE TO SATURATION. SO EXPECT ANY PERIOD OF VFR TO QUICKLY
DECAY TO MVFR BY 03Z WITH FURTHER DEGRADATION TO VLIFR IN DENSE
FOG. WINDS BECOME LIGHT AND VARIABLE.
MON THRU 18Z: VLIFR REMAINS A PROBLEM FOR AIR TRAVEL THRU 18Z.
EXPECT DENSE FOG CONTINUES THRU MIDDAY WITH GRADUAL IMPROVEMENT
AFTER 18Z. WINDS LIGHT AND VARIABLE.
CIG/VSBY CONFIDENCE: HIGH IN OCCURRENCE OF IFR
LOW IN TIMING OF IMPROVEMENT THIS AFTN
WIND CONFIDENCE: HIGH
WX CONFIDENCE: HIGH
&&
.PREV DISCUSSION... /ISSUED 1037 AM CST SUN JAN 27 2013/
1037 AM UPDATE... HAVE DROPPED OUR KS COUNTIES FROM THE ADVISORY
SINCE VIS SATL SHOWS A PERIOD OF CLEARING. ANOTHER AREA OF STRATUS
IS MOVING INTO PHILLIPS COUNTY AND WILL BE MOVING INTO ROOKS
COUNTY WITHIN THE HOUR. UNSURE HOW THIS EVOLVES BUT IT COULD PUT A
DAMPER ON OUR FCST HIGH TEMPS. AS WE MENTIONED YESTERDAY...THERE
IS ROOM FOR CONSIDERABLE BUST POTENTIAL IN TEMPS NEAR THE BOUNDARY
OF OVC VS CLR.
IN COORDINATION WITH LBF...HAVE EXTENDED MENTION OF PATCHY FOG
12PM-3PM AS A BUFFER FROM THE WIDESPREAD DENSE FOG MENTION WHICH
ENDS AT NOON.
HAVE ALSO LOWERED HOURLY TEMPS N OF I-80 FOR THE NEXT 3 HRS. WE
ARE SEEING BREAK IN THE OVC /BINOVC/ JUST NW OF BBW AND LBF. SO
THIS SHOULD ALLOW FOR SOME INCREASE IN TEMPS AS THE DAY
PROGRESSES.
HAVE MADE SOME HOURLY ADJUSTMENTS TO SKY FCST THRU 00Z. ALL
UPDATED PRODUCTS ARE OUT AND PUBLISHED TO THE WEB.
PREV DISCUSSION... /ISSUED 847 AM CST SUN JAN 27 2013/
846 AM UPDATE...VISIBILITIES CONTINUE TO DECAY. SO ISSUED A DENSE
FOG ADVISORY UNTIL NOON. FOG WILL LINGER IN SOME AREAS PAST
NOON...BUT VSBYS WILL IMPROVE TO MORE THAN A QUARTER MILE.
NPW/ZFP ARE OUT. HWO/EHWO WILL POST SHORTLY.
PREV DISCUSSION... /ISSUED 631 AM CST SUN JAN 27 2013/
AVIATION...12Z KGRI TAF. WILL STATE OFF THE TOP THAT THIS WILL BE
A CHALLENGING 24 HOURS IN TERMS OF PINNING DOWN THE TIMING OF
CEILING/VISIBILITY CHANGES...BUT THE BOTTOM LINE IS THAT A GOOD
CHUNK OF THE PERIOD WILL SEE DEGRADED FLIGHT CATEGORIES RANGING
BETWEEN LIFR AND MVFR. STARTING OFF RIGHT AWAY THIS
MORNING...IFR/LIFR CONDITIONS ARE FIRMLY IN PLACE...AND THIS IS
LIKELY TO PERSIST THROUGH MOST/ALL OF THE MORNING HOURS AS A
SATURATED LOW LEVEL AIRMASS PERSISTS IN THE PRESENCE OF LIGHT
SOUTHERLY BREEZES. WOULD NOT BE SURPRISED TO EVEN SEE A BRIEF
PERIOD OF VLIFR CONDITIONS IN DENSE FOG. THIS AFTERNOON...ANTICIPATE
VISIBILITY TO GRADUALLY IMPROVE INTO MVFR THEN VFR TERRITORY...WHILE
CEILING TRENDS GRADUALLY IMPROVE TO LOW-END MVFR BY MID-LATE
AFTERNOON. AS LOW LEVEL FLOW TURNS MORE WESTERLY LATE IN THE
AFTERNOON/EARLY THIS EVENING ...HAVE REASONABLE CONFIDENCE THAT
THERE SHOULD BE AT LEAST A 6 HOUR PERIOD OF VFR CONDITIONS AS THE
LOW LEVEL CEILING FINALLY LIFTS/SCATTERS OUT. ATTENTION THEN TURNS
TO THE LATE NIGHT HOURS...WHEN A LIGHT AND VARIABLE WIND REGIME
ALONG WITH WET GROUND WILL LIKELY FOSTER THE REDEVELOPMENT OF
FOG...ALTHOUGH TO WHAT EXTENT IS STILL UNKNOWN. FOR NOW...WILL
ADVERTISE PREVAILING IFR CONDITIONS DURING THE LAST FEW HOURS OF
THE PERIOD...AND DEFER TO LATER FORECASTS TO FINE TUNE THE
DETAILS.
PREV DISCUSSION... /ISSUED 449 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
LONG TERM...WEDNESDAY THROUGH SATURDAY. OVERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NEZ039>041-046>049-
060>064-072>077-082>086.
KS...NONE.
&&
$$
AVIATION...HALBLAUB 1144
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...PFANNCUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1130 AM CST SUN JAN 27 2013
.DISCUSSION...
UPDATED GRIDS AGAIN...THIS TIME TO REMOVE POPS FROM AFTERNOON
PERIOD IN ALL AREAS. LEFT A DRIZZLE MENTION UNDER LOW
STRATUS...BUT AREAS OF PRECIPITATION HAVE MOVED AWAY TO THE
EAST/NORTHEAST.
MAYES
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
CONDITIONS ARE LIKELY TO REMAIN BELOW MVFR THROUGH THE TAF CYCLE.
LOW CIGS AND LOWERED VIS TODAY WILL PROBABLY IMPROVE JUST BRIEFLY
THIS AFTERNOON. CIGS MAY ACTUALLY CLEAR OUT OF KOFK AND POSSIBLY
KLNK...BUT WITH AMPLE LOW-LEVEL MOISTURE AND WINDS BECOMING LIGHT
AND VARIABLE...FOG SHOULD BUILD IN SHORTLY AFTER MIDNIGHT AND
LINGER THROUGH MUCH OF THE MORNING. KEPT FOG A LITTLE LIGHTER AND
CIGS A LITTLE LOWER AND MORE OVERCAST AT KOMA AS THEY ARE NOT
LIKELY TO SEE BREAKS IN THE CLOUDS THIS AFTERNOON THROUGH
TONIGHT...BUT ALL SITES HAVE A RISK OF LOCKING DOWN AT 1/4SM FOR
SEVERAL HOURS TONIGHT AND MONDAY MORNING.
MAYES
&&
.PREV DISCUSSION... /ISSUED 938 AM CST SUN JAN 27 2013/
DISCUSSION...
HAVE MADE SEVERAL UPDATES TO THE GRIDS THIS MORNING TO REFLECT
ONGOING WEATHER TRENDS.
WITH SURFACE LOW AT 15Z CENTERED IN WESTERN KS/SOUTHEAST CO...DRY
SLOT IS EDGING INTO SOUTHERN/SOUTHEAST NEB THIS MORNING. PRECIP IS
JUST ABOUT OUT OF WESTERN IA...BUT SHOULD LINGER IN THE WRAPAROUND
AREA IN NORTHEAST NEB INTO THE AFTERNOON. THE DRY SLOT HAS FILLED
WITH LOW CIGS AND PATCHY FOG...BUT THINK THIS SHOULD IMPROVE THIS
AFTERNOON. HAVE UPDATED CLOUDS TO BE EVEN MORE PESSIMISTIC...WHILE
UPDATING WEATHER GRIDS TO REFLECT MORE DRIZZLE THAN RAIN AS SYSTEM
EXITS /EXCEPT IN NORTHEAST NEB/. ALSO CUT MAX TEMP FORECAST IN THE
SOUTHERN CWA...AS WARM NOSE AHEAD OF THE LOW IS BEING OFFSET BY
CLOUDS. KEPT MENTION FOR AREAS OF FOG TONIGHT AS LOW-LEVEL
MOISTURE MAY NOT SCOUR OUT UNDER WEAK LOW-LEVEL WINDS.
MAYES
PREV DISCUSSION... /ISSUED 233 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY.
HERE COMES THE RAIN. SURFACE TEMPERATURES HAVE REMAINED ABOVE
FREEZING THROUGH THE NIGHT AND WILL REMAIN THAT WAY THROUGH THE
DAY...THUS NO THREAT FOR FREEZING RAIN IN OUR FORECAST AREA THIS
MORNING. PRETTY SOLID BAND OF RAIN WILL CONTINUE TO PUSH TO THE
NORTH THIS MORNING AND THROUGH MOST OF THE FORECAST AREA BY EARLY
THIS AFTERNOON. A DEFINITIVE SOUTHERN EDGE WILL LIKELY EVEN CLEAR
SOUTHEAST NEBRASKA BEFORE 6 AM BASED ON LATEST RAP HOURLY DATA.
ONCE THE HEAVIER SHOWERS MOVE OUT...STRATUS WILL LIKELY PREVAIL
FOR THE AFTERNOON WITH AREAS OF DRIZZLE MAINLY ALONG AND NORTH OF
INTERSTATE 80...WHICH THEN PUSHES NORTHEAST OUT OF THE AREA
THROUGH THE EVENING. THERE COULD BE SOME BRIEF CLEARING BEHIND
THIS BY LATE EVENING. AT THAT POINT...BELIEVE WE WILL FOG BACK IN
THROUGH DAYBREAK MONDAY...WITH THE LOW LEVEL MOISTURE NOT REALLY
BEING SCRUBBED OUT. WINDS GO VERY LIGHT OR EVEN CALM IN MOST AREAS
BY 09-12Z MONDAY...WITH BOTH MAV/MET GUIDANCE SUGGESTING
WIDESPREAD FOG DEVELOPING...AND POSSIBLY DENSE IN MANY AREAS. THIS
WOULD PROBABLY LINGER INTO EARLY MONDAY MORNING...AND WOULD NOT BE
SURPRISED IF A DENSE FOG ADVISORY MAY EVENTUALLY BE NEEDED. OF
SOME CONCERN WOULD BE SURFACE TEMPERATURES DROPPING TO NEAR OR
BELOW FREEZING MONDAY MORNING ALONG AND NORTH OF I80...WHICH COULD
RESULT IN SLICK ROADWAYS FOR THE MORNING COMMUTE.
MONDAY IS A BIT OF A TRANSITION DAY WITH MUCH OF THE MID MISSOURI
VALLEY IN BETWEEN SYSTEMS. THE SURFACE WARM FRONT MAY LIFT BACK
TO THE NORTH TO NEAR I80 THROUGH THE DAY. MEANWHILE...THE NEXT
TROUGH MOVING THROUGH THE NORTHERN ROCKIES SHOULD START TO SPREAD
DEEPER MOISTURE INTO NORTHEAST NEBRASKA BY MONDAY AFTERNOON...BUT
CERTAINLY MONDAY NIGHT. AT THE SAME TIME...AN ADVANCING COLD FRONT
WILL ALSO BE USHERING IN COLDER AIR TO NORTHEAST NEBRASKA. SHOULD
SEE RAIN MIX WITH AND CHANGE TO SNOW ACROSS NORTHEAST NEBRASKA...AND
GIVEN THAT THIS IS OCCURRING AT NIGHT COULD PROBABLY EVEN SEEM
SOME MINOR ACCUMULATIONS OF AN INCH UP THERE BY DAYBREAK TUESDAY.
FURTHER SOUTH ALONG AND SOUTH OF I80...PRECIP POTENTIAL IS MORE
MORE QUESTIONABLE...BUT WILL MAINTAIN SLIGHT CHANCE POPS THAT
LINGER INTO TUESDAY AS WELL...BUT CERTAINLY COULD ALSO BE DRY
ACROSS ALL AREAS BUT NORTHEAST NEBRASKA.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
A TRANSITION TO A COLDER ARCTIC AIR MASS WILL CONTINUE EARLY IN
THE PERIOD WITH THE FIRST REINFORCING SHOT OF COLDER AIR OVERSPREADING
THE AREA ON WEDNESDAY WITH BLUSTERY NORTHWEST WINDS. HIGHS WILL BE
BACK IN THE UPPER TEENS NORTH TO UPPER 20S SOUTH...BUT COLDER
FEELING WITH THE WINDS. THE GFS HAS HINTED AT SOME FLURRY
POTENTIAL ACROSS NORTHEAST NEBRASKA AS H85 TEMPERATURES APPROACH
THE DENDRITIC RANGE...BUT THE ECMWF IS STILL DRY.
SECOND AND COLDER REINFORCING SURGE ARRIVES BY THURSDAY...AGAIN
WITH CONTINUED NORTHWEST BLUSTERY CONDITIONS. EVEN COLDER TEMPS
WELL WITHIN THE DENDRITIC RANGE WOULD SUGGEST SOME FLURRY
POTENTIAL AGAIN WITH HIGHS EVEN COLDER IN THE LOWER TEENS NORTH TO
MID 20S SOUTH...WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO ONCE AGAIN. SURFACE HIGH MOVES OVER THE AREA THURSDAY
NIGHT RESULTING IN LOWS IN THE SINGLE DIGITS ONE MORE TIME.
FRIDAY AND SATURDAY SHOULD BE TRANSITION DAYS BACK TO WARMER
TEMPS AGAIN WEST WESTERLY FLOW...DRY CONDITIONS AND HIGHS BACK
INTO THE MID TO UPPER 40S FOR THE WEEKEND.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1037 AM CST SUN JAN 27 2013
.1037 AM UPDATE... HAVE DROPPED OUR KS COUNTIES FROM THE ADVISORY
SINCE VIS SATL SHOWS A PERIOD OF CLEARING. ANOTHER AREA OF STRATUS
IS MOVING INTO PHILLIPS COUNTY AND WILL BE MOVING INTO ROOKS
COUNTY WITHIN THE HOUR. UNSURE HOW THIS EVOLVES BUT IT COULD PUT A
DAMPER ON OUR FCST HIGH TEMPS. AS WE MENTIONED YESTERDAY...THERE
IS ROOM FOR CONSIDERABLE BUST POTENTIAL IN TEMPS NEAR THE BOUNDARY
OF OVC VS CLR.
IN COORDINATION WITH LBF...HAVE EXTENDED MENTION OF PATCHY FOG
12PM-3PM AS A BUFFER FROM THE WIDESPREAD DENSE FOG MENTION WHICH
ENDS AT NOON.
HAVE ALSO LOWERED HOURLY TEMPS N OF I-80 FOR THE NEXT 3 HRS. WE
ARE SEEING BREAK IN THE OVC /BINOVC/ JUST NW OF BBW AND LBF. SO
THIS SHOULD ALLOW FOR SOME INCREASE IN TEMPS AS THE DAY
PROGRESSES.
HAVE MADE SOME HOURLY ADJUSTMENTS TO SKY FCST THRU 00Z. ALL
UPDATED PRODUCTS ARE OUT AND PUBLISHED TO THE WEB.
&&
.PREV DISCUSSION... /ISSUED 847 AM CST SUN JAN 27 2013/
846 AM UPDATE...VISIBILITIES CONTINUE TO DECAY. SO ISSUED A DENSE
FOG ADVISORY UNTIL NOON. FOG WILL LINGER IN SOME AREAS PAST
NOON...BUT VSBYS WILL IMPROVE TO MORE THAN A QUARTER MILE.
NPW/ZFP ARE OUT. HWO/EHWO WILL POST SHORTLY.
PREV DISCUSSION... /ISSUED 631 AM CST SUN JAN 27 2013/
AVIATION...12Z KGRI TAF. WILL STATE OFF THE TOP THAT THIS WILL BE
A CHALLENGING 24 HOURS IN TERMS OF PINNING DOWN THE TIMING OF
CEILING/VISIBILITY CHANGES...BUT THE BOTTOM LINE IS THAT A GOOD
CHUNK OF THE PERIOD WILL SEE DEGRADED FLIGHT CATEGORIES RANGING
BETWEEN LIFR AND MVFR. STARTING OFF RIGHT AWAY THIS
MORNING...IFR/LIFR CONDITIONS ARE FIRMLY IN PLACE...AND THIS IS
LIKELY TO PERSIST THROUGH MOST/ALL OF THE MORNING HOURS AS A
SATURATED LOW LEVEL AIRMASS PERSISTS IN THE PRESENCE OF LIGHT
SOUTHERLY BREEZES. WOULD NOT BE SURPRISED TO EVEN SEE A BRIEF
PERIOD OF VLIFR CONDITIONS IN DENSE FOG. THIS AFTERNOON...ANTICIPATE
VISIBILITY TO GRADUALLY IMPROVE INTO MVFR THEN VFR TERRITORY...WHILE
CEILING TRENDS GRADUALLY IMPROVE TO LOW-END MVFR BY MID-LATE
AFTERNOON. AS LOW LEVEL FLOW TURNS MORE WESTERLY LATE IN THE
AFTERNOON/EARLY THIS EVENING ...HAVE REASONABLE CONFIDENCE THAT
THERE SHOULD BE AT LEAST A 6 HOUR PERIOD OF VFR CONDITIONS AS THE
LOW LEVEL CEILING FINALLY LIFTS/SCATTERS OUT. ATTENTION THEN TURNS
TO THE LATE NIGHT HOURS...WHEN A LIGHT AND VARIABLE WIND REGIME
ALONG WITH WET GROUND WILL LIKELY FOSTER THE REDEVELOPMENT OF
FOG...ALTHOUGH TO WHAT EXTENT IS STILL UNKNOWN. FOR NOW...WILL
ADVERTISE PREVAILING IFR CONDITIONS DURING THE LAST FEW HOURS OF
THE PERIOD...AND DEFER TO LATER FORECASTS TO FINE TUNE THE
DETAILS.
PREV DISCUSSION... /ISSUED 449 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
LONG TERM...WEDNESDAY THROUGH SATURDAY. OVERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NEZ039>041-046>049-
060>064-072>077-082>086.
KS...NONE.
&&
$$
UPDATE...HALBLAUB 1037
SHORT TERM...WESELY
AVIATION...PFANNCUCH
LONG TERM...PFANNCUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
938 AM CST SUN JAN 27 2013
.DISCUSSION...
HAVE MADE SEVERAL UPDATES TO THE GRIDS THIS MORNING TO REFLECT
ONGOING WEATHER TRENDS.
WITH SURFACE LOW AT 15Z CENTERED IN WESTERN KS/SOUTHEAST CO...DRY
SLOT IS EDGING INTO SOUTHERN/SOUTHEAST NEB THIS MORNING. PRECIP IS
JUST ABOUT OUT OF WESTERN IA...BUT SHOULD LINGER IN THE WRAPAROUND
AREA IN NORTHEAST NEB INTO THE AFTERNOON. THE DRY SLOT HAS FILLED
WITH LOW CIGS AND PATCHY FOG...BUT THINK THIS SHOULD IMPROVE THIS
AFTERNOON. HAVE UPDATED CLOUDS TO BE EVEN MORE PESSIMISTIC...WHILE
UPDATING WEATHER GRIDS TO REFLECT MORE DRIZZLE THAN RAIN AS SYSTEM
EXITS /EXCEPT IN NORTHEAST NEB/. ALSO CUT MAX TEMP FORECAST IN THE
SOUTHERN CWA...AS WARM NOSE AHEAD OF THE LOW IS BEING OFFSET BY
CLOUDS. KEPT MENTION FOR AREAS OF FOG TONIGHT AS LOW-LEVEL
MOISTURE MAY NOT SCOUR OUT UNDER WEAK LOW-LEVEL WINDS.
MAYES
&&
.PREV DISCUSSION... /ISSUED 554 AM CST SUN JAN 27 2013/
AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK.
PRIMARILY IFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES FOR
MUCH OF THIS FORECAST PERIOD. THE GOOD NEWS...RAIN EVENT DEVELOPED
AND MOVED ACROSS THE FORECAST AREA THIS MORNING WITH TEMPERATURES
WARM ENOUGH TO KEEP RAIN FROM FREEZING. AFTER A BRIEF LULL DUE TO
DRY SLOT MOVING ACROSS THE AREA...CONDITIONS QUICKLY FILLED IN
BEHIND EXITING SYSTEM WITH WIDESPREAD IFR CIGS. AT THIS TIME CIGS
AND VSBYS FORECAST TO BECOME MVFR AFTER 06Z TIME FRAME. I REMAIN
CONCERNED ABOUT POSSIBLE IFR VSBYS LATE IN FORECAST PERIOD DUE TO
WEAK WEST FLOW WHICH NORMALLY IS NOT GOOD AT SCOURING OUT
LINGERING LOW LEVEL MOISTURE AND FOG.
MEYER
PREV DISCUSSION... /ISSUED 233 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY.
HERE COMES THE RAIN. SURFACE TEMPERATURES HAVE REMAINED ABOVE
FREEZING THROUGH THE NIGHT AND WILL REMAIN THAT WAY THROUGH THE
DAY...THUS NO THREAT FOR FREEZING RAIN IN OUR FORECAST AREA THIS
MORNING. PRETTY SOLID BAND OF RAIN WILL CONTINUE TO PUSH TO THE
NORTH THIS MORNING AND THROUGH MOST OF THE FORECAST AREA BY EARLY
THIS AFTERNOON. A DEFINITIVE SOUTHERN EDGE WILL LIKELY EVEN CLEAR
SOUTHEAST NEBRASKA BEFORE 6 AM BASED ON LATEST RAP HOURLY DATA.
ONCE THE HEAVIER SHOWERS MOVE OUT...STRATUS WILL LIKELY PREVAIL
FOR THE AFTERNOON WITH AREAS OF DRIZZLE MAINLY ALONG AND NORTH OF
INTERSTATE 80...WHICH THEN PUSHES NORTHEAST OUT OF THE AREA
THROUGH THE EVENING. THERE COULD BE SOME BRIEF CLEARING BEHIND
THIS BY LATE EVENING. AT THAT POINT...BELIEVE WE WILL FOG BACK IN
THROUGH DAYBREAK MONDAY...WITH THE LOW LEVEL MOISTURE NOT REALLY
BEING SCRUBBED OUT. WINDS GO VERY LIGHT OR EVEN CALM IN MOST AREAS
BY 09-12Z MONDAY...WITH BOTH MAV/MET GUIDANCE SUGGESTING
WIDESPREAD FOG DEVELOPING...AND POSSIBLY DENSE IN MANY AREAS. THIS
WOULD PROBABLY LINGER INTO EARLY MONDAY MORNING...AND WOULD NOT BE
SURPRISED IF A DENSE FOG ADVISORY MAY EVENTUALLY BE NEEDED. OF
SOME CONCERN WOULD BE SURFACE TEMPERATURES DROPPING TO NEAR OR
BELOW FREEZING MONDAY MORNING ALONG AND NORTH OF I80...WHICH COULD
RESULT IN SLICK ROADWAYS FOR THE MORNING COMMUTE.
MONDAY IS A BIT OF A TRANSITION DAY WITH MUCH OF THE MID MISSOURI
VALLEY IN BETWEEN SYSTEMS. THE SURFACE WARM FRONT MAY LIFT BACK
TO THE NORTH TO NEAR I80 THROUGH THE DAY. MEANWHILE...THE NEXT
TROUGH MOVING THROUGH THE NORTHERN ROCKIES SHOULD START TO SPREAD
DEEPER MOISTURE INTO NORTHEAST NEBRASKA BY MONDAY AFTERNOON...BUT
CERTAINLY MONDAY NIGHT. AT THE SAME TIME...AN ADVANCING COLD FRONT
WILL ALSO BE USHERING IN COLDER AIR TO NORTHEAST NEBRASKA. SHOULD
SEE RAIN MIX WITH AND CHANGE TO SNOW ACROSS NORTHEAST NEBRASKA...AND
GIVEN THAT THIS IS OCCURRING AT NIGHT COULD PROBABLY EVEN SEEM
SOME MINOR ACCUMULATIONS OF AN INCH UP THERE BY DAYBREAK TUESDAY.
FURTHER SOUTH ALONG AND SOUTH OF I80...PRECIP POTENTIAL IS MORE
MORE QUESTIONABLE...BUT WILL MAINTAIN SLIGHT CHANCE POPS THAT
LINGER INTO TUESDAY AS WELL...BUT CERTAINLY COULD ALSO BE DRY
ACROSS ALL AREAS BUT NORTHEAST NEBRASKA.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
A TRANSITION TO A COLDER ARCTIC AIR MASS WILL CONTINUE EARLY IN
THE PERIOD WITH THE FIRST REINFORCING SHOT OF COLDER AIR OVERSPREADING
THE AREA ON WEDNESDAY WITH BLUSTERY NORTHWEST WINDS. HIGHS WILL BE
BACK IN THE UPPER TEENS NORTH TO UPPER 20S SOUTH...BUT COLDER
FEELING WITH THE WINDS. THE GFS HAS HINTED AT SOME FLURRY
POTENTIAL ACROSS NORTHEAST NEBRASKA AS H85 TEMPERATURES APPROACH
THE DENDRITIC RANGE...BUT THE ECMWF IS STILL DRY.
SECOND AND COLDER REINFORCING SURGE ARRIVES BY THURSDAY...AGAIN
WITH CONTINUED NORTHWEST BLUSTERY CONDITIONS. EVEN COLDER TEMPS
WELL WITHIN THE DENDRITIC RANGE WOULD SUGGEST SOME FLURRY
POTENTIAL AGAIN WITH HIGHS EVEN COLDER IN THE LOWER TEENS NORTH TO
MID 20S SOUTH...WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO ONCE AGAIN. SURFACE HIGH MOVES OVER THE AREA THURSDAY
NIGHT RESULTING IN LOWS IN THE SINGLE DIGITS ONE MORE TIME.
FRIDAY AND SATURDAY SHOULD BE TRANSITION DAYS BACK TO WARMER
TEMPS AGAIN WEST WESTERLY FLOW...DRY CONDITIONS AND HIGHS BACK
INTO THE MID TO UPPER 40S FOR THE WEEKEND.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
847 AM CST SUN JAN 27 2013
.UPDATE...
VISIBILITIES CONTINUE TO DECAY. SO ISSUED A DENSE FOG ADVISORY
UNTIL NOON. FOG WILL LINGER IN SOME AREAS PAST NOON...BUT VSBYS
WILL IMPROVE TO MORE THAN A QUARTER MILE.
NPW/ZFP ARE OUT. HWO/EHWO WILL POST SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 631 AM CST SUN JAN 27 2013/
AVIATION...12Z KGRI TAF. WILL STATE OFF THE TOP THAT THIS WILL BE
A CHALLENGING 24 HOURS IN TERMS OF PINNING DOWN THE TIMING OF
CEILING/VISIBILITY CHANGES...BUT THE BOTTOM LINE IS THAT A GOOD
CHUNK OF THE PERIOD WILL SEE DEGRADED FLIGHT CATEGORIES RANGING
BETWEEN LIFR AND MVFR. STARTING OFF RIGHT AWAY THIS
MORNING...IFR/LIFR CONDITIONS ARE FIRMLY IN PLACE...AND THIS IS
LIKELY TO PERSIST THROUGH MOST/ALL OF THE MORNING HOURS AS A
SATURATED LOW LEVEL AIRMASS PERSISTS IN THE PRESENCE OF LIGHT
SOUTHERLY BREEZES. WOULD NOT BE SURPRISED TO EVEN SEE A BRIEF
PERIOD OF VLIFR CONDITIONS IN DENSE FOG. THIS AFTERNOON...ANTICIPATE
VISIBILITY TO GRADUALLY IMPROVE INTO MVFR THEN VFR TERRITORY...WHILE
CEILING TRENDS GRADUALLY IMPROVE TO LOW-END MVFR BY MID-LATE
AFTERNOON. AS LOW LEVEL FLOW TURNS MORE WESTERLY LATE IN THE
AFTERNOON/EARLY THIS EVENING ...HAVE REASONABLE CONFIDENCE THAT
THERE SHOULD BE AT LEAST A 6 HOUR PERIOD OF VFR CONDITIONS AS THE
LOW LEVEL CEILING FINALLY LIFTS/SCATTERS OUT. ATTENTION THEN TURNS
TO THE LATE NIGHT HOURS...WHEN A LIGHT AND VARIABLE WIND REGIME
ALONG WITH WET GROUND WILL LIKELY FOSTER THE REDEVELOPMENT OF
FOG...ALTHOUGH TO WHAT EXTENT IS STILL UNKNOWN. FOR NOW...WILL
ADVERTISE PREVAILING IFR CONDITIONS DURING THE LAST FEW HOURS OF
THE PERIOD...AND DEFER TO LATER FORECASTS TO FINE TUNE THE
DETAILS.
PREV DISCUSSION... /ISSUED 449 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
LONG TERM...WEDNESDAY THROUGH SATURDAY. OVERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NEZ039>041-046>049-
060>064-072>077-082>086.
KS...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR KSZ005-006-017.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
AVIATION...PFANNCUCH
LONG TERM...PFANNCUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
631 AM CST SUN JAN 27 2013
.AVIATION...12Z KGRI TAF. WILL STATE OFF THE TOP THAT THIS WILL BE
A CHALLENGING 24 HOURS IN TERMS OF PINNING DOWN THE TIMING OF
CEILING/VISIBILITY CHANGES...BUT THE BOTTOM LINE IS THAT A GOOD
CHUNK OF THE PERIOD WILL SEE DEGRADED FLIGHT CATEGORIES RANGING
BETWEEN LIFR AND MVFR. STARTING OFF RIGHT AWAY THIS
MORNING...IFR/LIFR CONDITIONS ARE FIRMLY IN PLACE...AND THIS IS
LIKELY TO PERSIST THROUGH MOST/ALL OF THE MORNING HOURS AS A
SATURATED LOW LEVEL AIRMASS PERSISTS IN THE PRESENCE OF LIGHT
SOUTHERLY BREEZES. WOULD NOT BE SURPRISED TO EVEN SEE A BRIEF
PERIOD OF VLIFR CONDITIONS IN DENSE FOG. THIS AFTERNOON...ANTICIPATE
VISIBILITY TO GRADUALLY IMPROVE INTO MVFR THEN VFR TERRITORY...WHILE
CEILING TRENDS GRADUALLY IMPROVE TO LOW-END MVFR BY MID-LATE
AFTERNOON. AS LOW LEVEL FLOW TURNS MORE WESTERLY LATE IN THE
AFTERNOON/EARLY THIS EVENING ...HAVE REASONABLE CONFIDENCE THAT
THERE SHOULD BE AT LEAST A 6 HOUR PERIOD OF VFR CONDITIONS AS THE
LOW LEVEL CEILING FINALLY LIFTS/SCATTERS OUT. ATTENTION THEN TURNS
TO THE LATE NIGHT HOURS...WHEN A LIGHT AND VARIABLE WIND REGIME
ALONG WITH WET GROUND WILL LIKELY FOSTER THE REDEVELOPMENT OF
FOG...ALTHOUGH TO WHAT EXTENT IS STILL UNKNOWN. FOR NOW...WILL
ADVERTISE PREVAILING IFR CONDITIONS DURING THE LAST FEW HOURS OF
THE PERIOD...AND DEFER TO LATER FORECASTS TO FINE TUNE THE
DETAILS.
&&
.PREV DISCUSSION... /ISSUED 449 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
LONG TERM...WEDNESDAY THROUGH SATURDAY. OVERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM/AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
554 AM CST SUN JAN 27 2013
.AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK.
PRIMARILY IFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES FOR
MUCH OF THIS FORECAST PERIOD. THE GOOD NEWS...RAIN EVENT DEVELOPED
AND MOVED ACROSS THE FORECAST AREA THIS MORNING WITH TEMPERATURES
WARM ENOUGH TO KEEP RAIN FROM FREEZING. AFTER A BRIEF LULL DUE TO
DRY SLOT MOVING ACROSS THE AREA...CONDITIONS QUICKLY FILLED IN
BEHIND EXITING SYSTEM WITH WIDESPREAD IFR CIGS. AT THIS TIME CIGS
AND VSBYS FORECAST TO BECOME MVFR AFTER 06Z TIME FRAME. I REMAIN
CONCERNED ABOUT POSSIBLE IFR VSBYS LATE IN FORECAST PERIOD DUE TO
WEAK WEST FLOW WHICH NORMALLY IS NOT GOOD AT SCOURING OUT
LINGERING LOW LEVEL MOISTURE AND FOG.
MEYER
&&
.PREV DISCUSSION... /ISSUED 233 AM CST SUN JAN 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY.
HERE COMES THE RAIN. SURFACE TEMPERATURES HAVE REMAINED ABOVE
FREEZING THROUGH THE NIGHT AND WILL REMAIN THAT WAY THROUGH THE
DAY...THUS NO THREAT FOR FREEZING RAIN IN OUR FORECAST AREA THIS
MORNING. PRETTY SOLID BAND OF RAIN WILL CONTINUE TO PUSH TO THE
NORTH THIS MORNING AND THROUGH MOST OF THE FORECAST AREA BY EARLY
THIS AFTERNOON. A DEFINITIVE SOUTHERN EDGE WILL LIKELY EVEN CLEAR
SOUTHEAST NEBRASKA BEFORE 6 AM BASED ON LATEST RAP HOURLY DATA.
ONCE THE HEAVIER SHOWERS MOVE OUT...STRATUS WILL LIKELY PREVAIL
FOR THE AFTERNOON WITH AREAS OF DRIZZLE MAINLY ALONG AND NORTH OF
INTERSTATE 80...WHICH THEN PUSHES NORTHEAST OUT OF THE AREA
THROUGH THE EVENING. THERE COULD BE SOME BRIEF CLEARING BEHIND
THIS BY LATE EVENING. AT THAT POINT...BELIEVE WE WILL FOG BACK IN
THROUGH DAYBREAK MONDAY...WITH THE LOW LEVEL MOISTURE NOT REALLY
BEING SCRUBBED OUT. WINDS GO VERY LIGHT OR EVEN CALM IN MOST AREAS
BY 09-12Z MONDAY...WITH BOTH MAV/MET GUIDANCE SUGGESTING
WIDESPREAD FOG DEVELOPING...AND POSSIBLY DENSE IN MANY AREAS. THIS
WOULD PROBABLY LINGER INTO EARLY MONDAY MORNING...AND WOULD NOT BE
SURPRISED IF A DENSE FOG ADVISORY MAY EVENTUALLY BE NEEDED. OF
SOME CONCERN WOULD BE SURFACE TEMPERATURES DROPPING TO NEAR OR
BELOW FREEZING MONDAY MORNING ALONG AND NORTH OF I80...WHICH COULD
RESULT IN SLICK ROADWAYS FOR THE MORNING COMMUTE.
MONDAY IS A BIT OF A TRANSITION DAY WITH MUCH OF THE MID MISSOURI
VALLEY IN BETWEEN SYSTEMS. THE SURFACE WARM FRONT MAY LIFT BACK
TO THE NORTH TO NEAR I80 THROUGH THE DAY. MEANWHILE...THE NEXT
TROUGH MOVING THROUGH THE NORTHERN ROCKIES SHOULD START TO SPREAD
DEEPER MOISTURE INTO NORTHEAST NEBRASKA BY MONDAY AFTERNOON...BUT
CERTAINLY MONDAY NIGHT. AT THE SAME TIME...AN ADVANCING COLD FRONT
WILL ALSO BE USHERING IN COLDER AIR TO NORTHEAST NEBRASKA. SHOULD
SEE RAIN MIX WITH AND CHANGE TO SNOW ACROSS NORTHEAST NEBRASKA...AND
GIVEN THAT THIS IS OCCURRING AT NIGHT COULD PROBABLY EVEN SEEM
SOME MINOR ACCUMULATIONS OF AN INCH UP THERE BY DAYBREAK TUESDAY.
FURTHER SOUTH ALONG AND SOUTH OF I80...PRECIP POTENTIAL IS MORE
MORE QUESTIONABLE...BUT WILL MAINTAIN SLIGHT CHANCE POPS THAT
LINGER INTO TUESDAY AS WELL...BUT CERTAINLY COULD ALSO BE DRY
ACROSS ALL AREAS BUT NORTHEAST NEBRASKA.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
A TRANSITION TO A COLDER ARCTIC AIR MASS WILL CONTINUE EARLY IN
THE PERIOD WITH THE FIRST REINFORCING SHOT OF COLDER AIR OVERSPREADING
THE AREA ON WEDNESDAY WITH BLUSTERY NORTHWEST WINDS. HIGHS WILL BE
BACK IN THE UPPER TEENS NORTH TO UPPER 20S SOUTH...BUT COLDER
FEELING WITH THE WINDS. THE GFS HAS HINTED AT SOME FLURRY
POTENTIAL ACROSS NORTHEAST NEBRASKA AS H85 TEMPERATURES APPROACH
THE DENDRITIC RANGE...BUT THE ECMWF IS STILL DRY.
SECOND AND COLDER REINFORCING SURGE ARRIVES BY THURSDAY...AGAIN
WITH CONTINUED NORTHWEST BLUSTERY CONDITIONS. EVEN COLDER TEMPS
WELL WITHIN THE DENDRITIC RANGE WOULD SUGGEST SOME FLURRY
POTENTIAL AGAIN WITH HIGHS EVEN COLDER IN THE LOWER TEENS NORTH TO
MID 20S SOUTH...WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO ONCE AGAIN. SURFACE HIGH MOVES OVER THE AREA THURSDAY
NIGHT RESULTING IN LOWS IN THE SINGLE DIGITS ONE MORE TIME.
FRIDAY AND SATURDAY SHOULD BE TRANSITION DAYS BACK TO WARMER
TEMPS AGAIN WEST WESTERLY FLOW...DRY CONDITIONS AND HIGHS BACK
INTO THE MID TO UPPER 40S FOR THE WEEKEND.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
449 AM CST SUN JAN 27 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MOST OF THE MEASURABLE
RAIN WILL HAVE EXITED OUR CWA TO THE NORTHEAST BY SUNRISE...BUT
DRIZZLE AND FOG WILL STILL BE A FACTOR FOR SOME AREAS TODAY. THE
TEMPERATURE FORECAST IS A BIG CHALLENGE...BUT EXPECT GENERALLY ABOVE
NORMAL TEMPERATURES THROUGH TUESDAY. A SECOND STORM SYSTEM WILL
ENTER OUR FORECAST AREA MONDAY NIGHT AND BRING WITH IT A CHALLENGING
MIXED PRECIPITATION TYPE FORECAST.
TODAY...THERE ARE NUMEROUS FORECAST CONCERNS CENTERED AROUND
POSSIBLE FOG...A STRATUS DECK THAT WILL BE DIFFICULT TO SHAKE
ESPECIALLY ACROSS NEBRASKA ZONES...A SHARP TEMPERATURE
GRADIENT...AND EVEN SOME PATCHY DRIZZLE. THE SREF AND HRRR ARE BOTH
INDICATING THE POSSIBILITY OF FOG BEHIND THE DEPARTING RAIN BAND
WITH THE POTENTIAL OF VISIBILITY REDUCTIONS TO LESS THAN ONE
QUARTER MILE. THIS FOG HAS YET TO MATERIALIZE THUS FAR THIS
MORNING...BUT CEILING HEIGHTS HAVE BEEN FALLING AND THE WIND WILL
BEGIN TO DIE DOWN SOME ACROSS OUR WEST AFTER SUNRISE.
THEREFORE...WILL CONTINUE TO INCLUDE POSSIBLE FOG IN OUR FORECAST
FOR THIS MORNING. THERE HAS BEEN SOME DRIZZLE BEHIND THE RAIN BAND
AND THIS IS ALSO LIKELY TO CONTINUE THROUGH AT LEAST A PORTION OF
THE MORNING ESPECIALLY ACROSS EASTERN ZONES. THE DRIZZLE MAY EVEN
LINGER OVER OUR FAR EAST THROUGH EARLY THIS AFTERNOON. MOST FORECAST
MODELS BRING THE CLEARING LINE INTO KANSAS THIS AFTERNOON BUT KEEP
MOST NEBRASKA ZONES SOCKED IN UNDER A LOW STRATUS DECK. THUS THERE
WILL BE A TIGHT TEMPERATURE GRADIENT ALONG THE EDGE OF THIS STRATUS
DECK...WHICH SHOULD BE LOCATED SOMEWHERE NEAR THE NEBRASKA KANSAS
BORDER THIS AFTERNOON.
TONIGHT...THE WET GROUND FROM THE RECENT RAIN ALONG WITH LIGHT AND
VARIABLE WINDS WILL MAKE FOG POSSIBLE. THEREFORE...WILL CONTINUE TO
CALL FOR AT LEAST THE POSSIBILITY OF SOME FOG LATE TONIGHT INTO
EARLY MONDAY MORNING.
MONDAY...THE NEXT UPPER TROUGH WILL BE DIGGING ACROSS THE WESTERN
CONUS WITH AN ASSOCIATED SFC LOW DEVELOPING OVER EASTERN COLORADO.
THE WIND WILL BE SOUTHERLY ACROSS THE PLAINS AHEAD OF THIS LOW AND
WE SHOULD WARM UP NICELY WITH HIGH TEMPERATURES POTENTIALLY WELL
ABOVE NORMAL. HOWEVER...THERE IS UNCERTAINTY IN THE LOW CLOUD
FORECAST ON MONDAY...WHICH IF PRESENT...THESE LOW CLOUDS WOULD
REALLY HAMPER OUR WARM UP.
MONDAY NIGHT INTO TUESDAY...THE UPPER WAVE AND SFC LOW WILL PRESS
THROUGH OUR FORECAST AREA WITH A COLD FRONT SWEEPING THROUGH. THIS
IS A PROGRESSIVE FAST MOVING OPEN WAVE. THUS ANY DEFORMATION SNOW
BAND WILL BE WEAK WITH LITTLE IF ANY SNOW ACCUMULATION. THE 00Z
ECMWF AND 00Z GFS PLACE A BAND OF RAIN AND SNOW ACROSS OUR NORTHWEST
ZONES MONDAY EVENING...WHICH SHOULD TURN OVER TO ALL SNOW AT SOME
POINT AFTER MIDNIGHT. THIS BAND HEADS MORE NORTHEAST RATHER THAN
SOUTHEAST...AND OUR SOUTHEAST ZONES MAY STAY COMPLETELY DRY. THE MOST
AGGRESSIVE MODEL GENERALLY IS CALLING FOR ONE INCH OR LESS OF SNOW
ACROSS OUR NORTHWEST...SO THIS IS NOT APPEARING TO BE A BIG DEAL FOR
OUR AREA. TUESDAY WILL BE COOLER BEHIND THE COLD FRONT...BUT STILL
ABOVE NORMAL AS THE COLDER AIR WILL TAKE SOME TIME TO SETTLE IN.
.LONG TERM...WEDNESDAY THROUGH SATURDAY. OVEERALL NO MAJOR CHANGES
TO THESE 4 DAYS FROM PREVIOUS FORECAST...ALTHOUGH A SLIGHT CHANCE
OF SNOW HAS BEEN INTRODUCED FOR PARTS OF THE CWA THURSDAY...AND
HIGH TEMPS FOR FRIDAY CONTINUE TO TREND UP A BIT. CONFIDENCE IS
FAIRLY HIGH THAT THE MAJORITY OF THIS TIME FRAME IS PRECIPITATION
FREE EXCEPT FOR MAYBE THURSDAY...WHICH ALSO LOOKS LIKE THE COLDEST
DAY OF THE UPCOMING WEEK.
STARTING OFF WEDNESDAY/WED NIGHT...00Z ECMWF/GFS RUNS ARE IN GOOD
AGREEMENT ON THE BIG PICTURE. ALOFT DURING THE DAY...THE LOCAL
AREA WILL SEE NORTHWEST FLOW BEHIND THE DEPARTURE OF A LARGE
SCALE TROUGH AXIS THAT EXTENDS NORTH-SOUTH THROUGH THE HEART OF
THE NATION...WITH THIS TROUGH AXIS PROGRESSING EAST TOWARD THE
EASTERN MIDWEST/OHIO VALLEY REGION BY DAYS END. THEN ON WED
NIGHT...A SHORTWAVE TROUGH DROPS SOUTHWARD OUT OF CANADA INTO THE
DAKOTAS...REINFORCING THE TROUGHY PATTERN DOMINATING THE MAJORITY
OF THE CONUS BY THIS TIME. CONFIDENCE IS FAIRLY HIGH IN A
PRECIPITATION-FREE 24 HOURS HERE...AT LEAST OF THE MEASURABLE
VARIETY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW FLURRIES
STILL BRUSHING EASTERN ZONES DURING THE DAY...AND THEN ANOTHER
BATCH OF FLURRIES/LIGHT SNOW POSSIBLY APPROACHING NORTHERN/WESTERN
COUNTIES LATE WEDNESDAY NIGHT...BUT BOTH OF THESE POSSIBILITIES
SEEM LOW ENOUGH FOR NOW TO LEAVE OUT. TEMP-WISE...MADE VERY
LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...AS WEDNESDAY SHOULD BE
ROUGHLY 10 DEGREES COOLER THAN TUESDAY IN THE WAKE OF THE FIRST OF
TWO MID-WEEK COLD FRONTS. HIGHS ARE AIMED TO RANGE FROM MID-UPPER
20S FAR NORTHEAST...NEAR 30 TRI-CITIES...MID- UPPER 30S SOUTHWEST.
THURSDAY/THURS NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF SNOW FOR
ROUGHLY THE SOUTHWEST 1/3 OF THE CWA FOR THE DAYTIME HOURS...AND
WOULD NOT BE SURPRISED TO SEE THIS SLIGHT CHANCE OF SNOW OR AT
LEAST FLURRIES EXPANDED TO COVER MORE OF OUR AREA IN LATER
FORECASTS IF TRENDS FROM THE 00Z ECMWF/GEM CONTINUE. IN
SHORT...THIS LOOKS LIKE A FAVORABLE SETUP FOR A QUICK-HITTING
MINOR SNOW ACCUMULATION...AS THE AFOREMENTIONED NORTHWEST-FLOW
SHORTWAVE TROUGH THAT DROPS INTO THE DAKOTAS WED NIGHT CONTINUES
TO SINK SOUTHEAST ACROSS EASTERN NEB/IA ON THURSDAY...AND A NORTH-
SOUTH ORIENTED UPPER JET STREAK APPROACHES OUR LOCAL AREA FROM THE
NORTHWEST...HELPING FOCUS A BAND OF MID LEVEL LIFT/SATURATION. NOT
LOOKING LIKE HIGH-IMPACT BY ANY MEANS...BUT SOMETHING TO KEEP AN
EYE ON. BY THURSDAY NIGHT...FORCING FOR ANY NUISANCE SNOW SHOULD
HAVE MOVED OFF TO THE SOUTHEAST. IN THE LOW LEVELS...THE SECOND
AND STRONGER COLD FRONT OF THE WEEK ENTERS THE CWA DURING THE
DAY...ALTHOUGH THE CORE OF THE TRULY COLD AIR SHOULD REMAIN AT
LEAST A FEW HUNDRED MILES TO OUR NORTHEAST...MUCH AS SEEN WITHIN
THE PAST WEEK. CERTAINLY THIS WILL RESULT IN A SHARP AND HARD-TO-
PIN-DOWN SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT FOR HIGHS ON
THURSDAY...AND HAVE SHAVED A COUPLE DEGREES OFF PREVIOUS FORECAST
ALL AREAS...AIMING FOR A RANGE FROM NEAR 20 FAR NORTHEAST...MID-
UPPER 20S TRI-CITIES AND MID 30S SOUTHWEST. MUCH COLDER AIR WILL
NOT BE FAR AWAY...WITH SINGLE DIGIT HIGHS POSSIBLY AS CLOSE AS FAR
NORTHEAST NEB...SO WOULD NOT BE SURPRISED TO SEE THIS COLDER AIR
PUSH SOUTHWEST INTO OUR AREA A BIT MORE AGGRESSIVELY THAN
CURRENTLY ADVERTISED.
FRIDAY/FRIDAY NIGHT...THE REGION REMAINS IN WEST-NORTHWEST FLOW
ALOFT...AS A COUPLE SHORTWAVE TROUGHS PASS THROUGH THE FLOW...ONE
STAYING WELL NORTH FROM CANADA INTO THE NORTHERN GREAT LAKES...AND
THE OTHER SLIDING INTO OR JUST SOUTHWEST OF THE AREA. AT THIS
TIME...NOTHING APPEARS STRONG ENOUGH TO GENERATE PRECIP FOR OUR
CWA. THE BIGGER STORY IS A POTENTIALLY DECENT WARM-UP OVER
THURSDAY...AS THE COLD LOW LEVEL RIDGE AXIS SLIDES EAST AND ALLOWS
WARMER AIR TO INVADE THE CENTRAL PLAINS ON WESTERLY OR SOUTHERLY
BREEZES. HAVE RAISED FRIDAY HIGHS 3-4 DEGREES FROM PREVIOUS
FORECAST PER MULTI-MODEL ALLBLEND...NOW RANGING FROM MID 30S
NORTHEAST TO LOW-MID 40S SOUTHWEST.
SATURDAY CURRENTLY HAS RATHER HIGH CONFIDENCE OF BEING
PRECIP-FREE...AND IS ALSO LOOKING LIKE THE WARMEST DAY SINCE
MONDAY...AND MADE ALMOST NO CHANGE TO PREVIOUS HIGHS RANGING FROM
MID 40S NORTHEAST TO UPPER 40S/LOW 50S SOUTH AND WEST. THE ECWMF
SUGGESTS THERE COULD BE A DECENT NORTHWEST BREEZE AS THE REGION IS
GLANCED BY A THE EDGES OF A WEAK COLD FRONT DRIVEN BY ANOTHER
GREAT LAKES SHORTWAVE TROUGH...BUT EVEN SO DECENT MIXING AND A
DOWNSLOPE WIND COMPONENT WOULD HELP AID A WARM-UP.
&&
.PREV DISCUSSION... /ISSUED 1003 PM CST SAT JAN 26 2013/
AVIATION...06Z KGRI TAF...DETERIORATING CONDITIONS ARE EXPECTED
AT THE TERMINAL THROUGH THE OVERNIGHT HOURS AS AN UPPER LEVEL
DISTURBANCE OUT OF THE DESERT SOUTHWEST EJECTS INTO THE PLAINS. AS
A RESULT...MVFR CEILING ARE EXPECTED TO DEVELOP AT THE TERMINAL
OVER THE NEXT OR TWO...WITH CEILINGS CONTINUING TO LOWER AND
LIGHT RAIN ALONG WITH MVFR VSBYS ARE EXPECTED TO REACH THE
TERMINAL AROUND 08Z-09Z. WHILE THE RAINFALL IS EXPECTED TO STOP
DURING THE EARLY MORNING HOURS...LOW LEVEL STRATUS AND IFR CIGS
ARE EXPECTED TO PERSIST THROUGH MID AFTERNOON...BEFORE WINDS SHIFT
AND BECOME SOUTHWESTERLY AROUND 27/18Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
233 AM CST SUN JAN 27 2013
.SHORT TERM...TODAY THROUGH TUESDAY.
HERE COMES THE RAIN. SURFACE TEMPERATURES HAVE REMAINED ABOVE
FREEZING THROUGH THE NIGHT AND WILL REMAIN THAT WAY THROUGH THE
DAY...THUS NO THREAT FOR FREEZING RAIN IN OUR FORECAST AREA THIS
MORNING. PRETTY SOLID BAND OF RAIN WILL CONTINUE TO PUSH TO THE
NORTH THIS MORNING AND THROUGH MOST OF THE FORECAST AREA BY EARLY
THIS AFTERNOON. A DEFINITIVE SOUTHERN EDGE WILL LIKELY EVEN CLEAR
SOUTHEAST NEBRASKA BEFORE 6 AM BASED ON LATEST RAP HOURLY DATA.
ONCE THE HEAVIER SHOWERS MOVE OUT...STRATUS WILL LIKELY PREVAIL
FOR THE AFTERNOON WITH AREAS OF DRIZZLE MAINLY ALONG AND NORTH OF
INTERSTATE 80...WHICH THEN PUSHES NORTHEAST OUT OF THE AREA
THROUGH THE EVENING. THERE COULD BE SOME BRIEF CLEARING BEHIND
THIS BY LATE EVENING. AT THAT POINT...BELIEVE WE WILL FOG BACK IN
THROUGH DAYBREAK MONDAY...WITH THE LOW LEVEL MOISTURE NOT REALLY
BEING SCRUBBED OUT. WINDS GO VERY LIGHT OR EVEN CALM IN MOST AREAS
BY 09-12Z MONDAY...WITH BOTH MAV/MET GUIDANCE SUGGESTING
WIDESPREAD FOG DEVELOPING...AND POSSIBLY DENSE IN MANY AREAS. THIS
WOULD PROBABLY LINGER INTO EARLY MONDAY MORNING...AND WOULD NOT BE
SURPRISED IF A DENSE FOG ADVISORY MAY EVENTUALLY BE NEEDED. OF
SOME CONCERN WOULD BE SURFACE TEMPERATURES DROPPING TO NEAR OR
BELOW FREEZING MONDAY MORNING ALONG AND NORTH OF I80...WHICH COULD
RESULT IN SLICK ROADWAYS FOR THE MORNING COMMUTE.
MONDAY IS A BIT OF A TRANSITION DAY WITH MUCH OF THE MID MISSOURI
VALLEY IN BETWEEN SYSTEMS. THE SURFACE WARM FRONT MAY LIFT BACK
TO THE NORTH TO NEAR I80 THROUGH THE DAY. MEANWHILE...THE NEXT
TROUGH MOVING THROUGH THE NORTHERN ROCKIES SHOULD START TO SPREAD
DEEPER MOISTURE INTO NORTHEAST NEBRASKA BY MONDAY AFTERNOON...BUT
CERTAINLY MONDAY NIGHT. AT THE SAME TIME...AN ADVANCING COLD FRONT
WILL ALSO BE USHERING IN COLDER AIR TO NORTHEAST NEBRASKA. SHOULD
SEE RAIN MIX WITH AND CHANGE TO SNOW ACROSS NORTHEAST NEBRASKA...AND
GIVEN THAT THIS IS OCCURRING AT NIGHT COULD PROBABLY EVEN SEEM
SOME MINOR ACCUMULATIONS OF AN INCH UP THERE BY DAYBREAK TUESDAY.
FURTHER SOUTH ALONG AND SOUTH OF I80...PRECIP POTENTIAL IS MORE
MORE QUESTIONABLE...BUT WILL MAINTAIN SLIGHT CHANCE POPS THAT
LINGER INTO TUESDAY AS WELL...BUT CERTAINLY COULD ALSO BE DRY
ACROSS ALL AREAS BUT NORTHEAST NEBRASKA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
A TRANSITION TO A COLDER ARCTIC AIR MASS WILL CONTINUE EARLY IN
THE PERIOD WITH THE FIRST REINFORCING SHOT OF COLDER AIR OVERSPREADING
THE AREA ON WEDNESDAY WITH BLUSTERY NORTHWEST WINDS. HIGHS WILL BE
BACK IN THE UPPER TEENS NORTH TO UPPER 20S SOUTH...BUT COLDER
FEELING WITH THE WINDS. THE GFS HAS HINTED AT SOME FLURRY
POTENTIAL ACROSS NORTHEAST NEBRASKA AS H85 TEMPERATURES APPROACH
THE DENDRITIC RANGE...BUT THE ECMWF IS STILL DRY.
SECOND AND COLDER REINFORCING SURGE ARRIVES BY THURSDAY...AGAIN
WITH CONTINUED NORTHWEST BLUSTERY CONDITIONS. EVEN COLDER TEMPS
WELL WITHIN THE DENDRITIC RANGE WOULD SUGGEST SOME FLURRY
POTENTIAL AGAIN WITH HIGHS EVEN COLDER IN THE LOWER TEENS NORTH TO
MID 20S SOUTH...WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO ONCE AGAIN. SURFACE HIGH MOVES OVER THE AREA THURSDAY
NIGHT RESULTING IN LOWS IN THE SINGLE DIGITS ONE MORE TIME.
FRIDAY AND SATURDAY SHOULD BE TRANSITION DAYS BACK TO WARMER
TEMPS AGAIN WEST WESTERLY FLOW...DRY CONDITIONS AND HIGHS BACK
INTO THE MID TO UPPER 40S FOR THE WEEKEND.
DEWALD
&&
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
DETERIORATING CONDITIONS ARE EXPECTED AS AREA OF RAIN MOVES INTO
EASTERN NEBRASKA THIS MORNING. MVFR CIGS/VSBYS WITH INITIAL SURGE
OF PRECIPITATION IN 08Z-11Z TIME FRAME WILL DECREASE TO IFR BY
12Z-14Z. RAIN WILL MOVE OUT OF AREA BY 18Z...BUT LINGERING LOW
CLOUDS AND MVFR VSBYS ARE EXPECTED IN DRIZZLE AND FOG. A PERIOD OF
VFR CONDITIONS IS POSSIBLE BETWEEN 21Z AND 02Z...BUT LIGHT WINDS
AND LINGERING LOW LEVEL MOISTURE WILL SET THE STAGE FOR IFR OR
LOWER CIGS/VSBYS AS WINDS DECREASE AND FOG FORMS TOWARD END OF TAF
PERIOD.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1147 PM CST SAT JAN 26 2013
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
DETERIORATING CONDITIONS ARE EXPECTED AS AREA OF RAIN MOVES INTO
EASTERN NEBRASKA THIS MORNING. MVFR CIGS/VSBYS WITH INITIAL SURGE
OF PRECIPITATION IN 08Z-11Z TIME FRAME WILL DECREASE TO IFR BY
12Z-14Z. RAIN WILL MOVE OUT OF AREA BY 18Z...BUT LINGERING LOW
CLOUDS AND MVFR VSBYS ARE EXPECTED IN DRIZZLE AND FOG. A PERIOD OF
VFR CONDITIONS IS POSSIBLE BETWEEN 21Z AND 02Z...BUT LIGHT WINDS
AND LINGERING LOW LEVEL MOISTURE WILL SET THE STAGE FOR IFR OR
LOWER CIGS/VSBYS AS WINDS DECREASE AND FOG FORMS TOWARD END OF TAF
PERIOD.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 331 PM CST SAT JAN 26 2013/
SHORT TERM...TONIGHT THROUGH TUESDAY
SHORT TERM FORECAST CONCERNS WILL BE THE ASSOCIATED DETAILS WITH
THE PRECIPITATION EVENT TONIGHT AND SUNDAY...THEN DRIZZLE AND FOG
AS LIFT DECREASES LATER SUNDAY INTO SUNDAY NIGHT. POTENTIAL FOR
LIGHT PRECIPITATION MONDAY IN SOUTHEAST NEB NEAR H85 FRONT AND IN
THE NORTHEAST NEB WITH A COLD FRONT AND ACROSS THE FORECAST AREA
INTO TUESDAY.
THE SURFACE WARM FRONT IS LIFTING NORTH AND BRISK SOUTH WINDS HAVE
WARMED TEMPERATURES INTO THE 40S AND 50S...WITH BEATRICE NEARLY
REACHING 60. SURFACE DEWPOINTS ARE VARIABLE IN THE TEENS AND 20S.
3HR PRESSURE FALLS WERE NOTED ACROSS MUCH OF THE PLAINS IN
RESPONSE TO LOWERING PRESSURE OVER THE EASTERN ROCKIES.
PER VISIBLE SATELLITE AND METARS...LOW LEVEL STRATUS IS BEGINNING
TO WORK NORTH AND THIS IS THE LEADING EDGE OF THE MID 30S
DEWPOINTS. WATER VAPOR SATELLITE IMAGERY AND LIGHTNING
DATA...SHOWED THE SHORTWAVE TROF HAD MOVED INTO THE SOUTHWEST
U.S. BY MIDDAY AND THERE WERE LIGHTNING STRIKES OVER EASTERN
ARIZONA. THIS WAVE WILL BE OUR WEATHER MAKER THROUGH SUNDAY.
THE H9 JET IS FROM THE SOUTH AT 25 TO 35KT AND WILL CONTINUE TO
INCREASE TO 35 TO 45KT OVER THE FORECAST AREA THROUGH 06Z.
MEANWHILE...THE NOSE OF THE H85 50KT JET IS OVER SOUTHWEST KS.
THETA-ADVECTION AND H7 OMEGA INCREASE ACROSS KANSAS THROUGH 06Z
AND THEN ACROSS NEBRASKA INTO IOWA AND MISSOURI THROUGH 12Z. THERE
ALSO IS SOME UPPER LEVEL JET SUPPORT BY 12Z.
THE 4KM WRF/NAM/GFS/SREF/EC/RAP ARE SIMILAR IN HAVING THE
PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO
NORTHEAST MAINLY BETWEEN 08Z AND 14Z. REGARDING PRECIPITATION
TYPE...WILL NEED TO MONITOR AREAS IN FAR NORTHEAST NEBRASKA AND
PARTS OF WESTERN IOWA SHOULD PRECIPITATION BEGIN AS FREEZING RAIN.
THE MODELS ARE NOT IN GOOD AGREEMENT WITH THE LOW LEVEL TEMPS. THE
NAM SEEMS QUITE COOL...AND SEVERAL OF THE OTHER MODELS ARE A BIT
WARMER. TRENDED WITH THE WARMER RAP TEMPERATURES VERSUS THE
COOLER NAM TEMPS. WITH THE VERY MILD CONDITIONS THIS EVENING AND
INCREASING CLOUDS AND STRONG SOUTH FLOW...THINK MOST LOCATIONS
WILL BE ABOVE FREEZING WHEN THE PRECIPITATION STARTS...SO LEFT
FREEZING MENTION ONLY IN THE FAR NORTHEAST ZONES. AS THE SHORTWAVE
MOVES EAST...SO DOES THE PRECIPITATION AND LOOK FOR DRIZZLE AND
FOG LATER SUNDAY AFTERNOON AND SUNDAY NIGHT. RAINFALL AMOUNTS
LOOK TO VARY FROM 0.1 TO .4 OF AN INCH.
THE COLD FRONT IS NEAR FALLS CITY BY 06Z SUNDAY NIGHT...HOWEVER
THE LOW LEVEL MOISTURE DOES NOT GET SCOURED OUT. WITH THE WEAK
FLOW OVERNIGHT DO MENTION FOG. WILL NEED TO WATCH FOR BELOW
FREEZING TEMPERATURES AND FOG FOR THE MONDAY MORNING COMMUTE...AS
THIS COULD CAUSE PROBLEMS.
MONDAY...THERE IS WARM AIR ADVECTION ACROSS THE SOUTHERN CWA
AND MAY SEE SOME LIGHT PRECIP. IN THE NORTHWEST PART OF THE
FORECAST AREA...THERE IS A REINFORCING COLD FRONT SLOWLY MOVING
SOUTHEAST ASSOCIATED WITH THE MID LEVEL TROF. THIS FRONT HAS SOME
DECENT FRONTOGENESIS WITH IT AND MONDAY INTO TUESDAY COULD BRING
SOME RAIN...A MIX AND THEN POSSIBLE A NARROW BAND OF LIGHT SNOW.
IT IS INTERESTING THAT THERE IS SOME ELEVATED INSTABILITY WITH
THIS BAND AND ALSO NEAR THE H85 FRONT IN SOUTHERN NEBRASKA MONDAY
NIGHT. FOR NOW...TOP/EAX HAVE SOME TSRA MENTIONED IN THEIR CWA
MONDAY NIGHT AND WE HAVE RAIN IN THE SOUTH AND A RAIN/SNOW MIX
THEN ALL SNOW NORTH.
TEMPERATURES ARE GOING TO BE A CHALLENGE EACH DAY AND HAVE HIGHS
SUNDAY AND MONDAY IN THE 30S TO AROUND 40 FAR NORTH TO THE 50S
SOUTH. TUESDAY HAVE HIGHS IN THE LOWER 30S NORTH TO UPPER 40S
SOUTH.
ZAPOTOCNY
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
THE UPPER LEVEL FLOW PATTERN WILL TRANSITION TO THE NORTHWEST
DURING THIS PERIOD AND THE GLOBAL MODELS ARE IN PRETTY GOOD
AGREEMENT ON THIS EVOLUTION. THE UPPER LEVEL TROUGH FOR MON/TUE WILL
JUST BE EXITING THE REGION ON TUE NIGHT AND WILL LINGER SOME SCHC
POPS FOR -SN IN THE SOUTH AS THIS EXITS...OTHERWISE THE EXTENDED
PART OF THE FORECAST IS DRY. AN ARCTIC COLD FRONT WILL MOVE THROUGH
THE FA ON WED NIGHT WHICH WILL LEAD TO MUCH COLDER HIGHS ON THU AND
LOWS THU NIGHT. BUT LIKE RECENT COLD SURGES...THIS WILL BE GREATLY
MODIFIED BY THE LACK OF SNOW COVER ACROSS THE FA. THUS WE ARE
EXPECTING HIGHS IN THE TEENS/20S AND LOWS IN THE SINGLE DIGITS ABOVE
ZERO. THE UPPER LEVEL RIDGE TO THE WEST WILL SHIFT A BIT EAST ON ON
FRI/SAT AND ALLOW FOR SOME DOWN-SLOPE AND PACIFIC AIR TO SPILL BACK
INTO THE FA. NORMAL HIGHS WITH NO SNOW COVER BY THE END OF THE
PERIOD ARE IN THE LOWER TO MID 40S...AND WE SEE NO REASON WE CAN`T
GET NEAR THESE NUMBERS. THUS WE HAVE GONE ABOVE THE CLIMO HEAVY MOS
GUIDANCE FOR THE END OF THE PERIOD.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
645 AM EST SUN JAN 27 2013
.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL HOLD OVER THE AREA TODAY. AN UPPER
LEVEL DISTURBANCE WILL PASS NORTHEASTWARD THROUGH THE REGION TONIGHT
THROUGH MONDAY MORNING. THE SURFACE HIGH WILL MOVE OFF THE COAST
LATE MONDAY...FOLLOWED BY A WARM SOUTHWEST FLOW INTO THE REGION
THROUGH MIDWEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 310 AM SUNDAY...
THROUGH SUNRISE...THE MAIN CONCERN ARE THE PATCHES OF DENSE FOG THAT
HAVE DEVELOPED ACROSS PORTIONS OF OUR CWA INCLUDING THE TRIANGLE
REGION. WE SUSPECT THAT LINGERING GROUND MOISTURE AND PATCHES OF ICE
COVER FROM FRIDAYS STORM HAVE HELPED INITIATE THE DENSER PATCHES OF
FOG. NOTED THAT THE HRRR CAPTURED THIS FOG PRETTY WELL...AND SHOWS
IT CONTINUING THROUGH AROUND 12Z OR SO. GIVEN THE LIMITED NATURE OF
THE 1/4 MILE VSBY REPORTS...FOR NOW WE HAVE THIS COVERED WITH AN SPS
AND WILL MONITOR AS THE MORNING PROGRESSES.
FOR THE DAYTIME TODAY AFTER FOG BURNS OFF...EXPECT LOW-IMPACT
WEATHER AS THE S/W RIDGE CURRENTLY OVER THE MS VALLEY DRIFTS EAST
TOWARD US AND THE SFC RIDGE REMAINS OVER THE CAROLINAS. DESPITE
FORECAST SOUNDINGS DEPICTING A COOLER BL TODAY COMPARED TO
YESTERDAY`S OBSERVED SOUNDING...EXPECT MORE SUNSHINE THAN YESTERDAY
WHICH SHOULD HELP TEMPS CLIMB A FEW DEGREES HIGHER THAN YESTERDAY...
RESULTING IN HIGHS AROUND 40 NORTH TO 46 SOUTH.
FOR TONIGHT..THE MAIN CONCERN IS EVOLVING PRECIP POTENTIAL. THE
MIDLEVEL RIDGE AXIS IS PROGGED TO SET UP OVER THE SOUTHEAST AND WILL
INITIATE WAA ACROSS OUR AREA THAT WILL TAKE PLACE ABOVE THE
SHALLOW COOLER NEAR-SFC LAYER. MODELS ARE GENERALLY DEPICTING THE
MORE SIGNIFICANT SYNOP SCALE LIFT AND MOISTURE TRANSPORT OCCURRING
TO OUR NORTH CLOSER TO A S/W TROUGH THAT WILL BE MOVING ACROSS THE
MIDWEST REGION. THE GFS IS THE MOST GENEROUS REGARDING QPF ACROSS
OUR AREA OVERNIGHT...WHILE OTHER MODELS KEEP MOST IF NOT ALL OF THE
QPF NORTH OF THE VA/NC STATE LINE. IF LIGHT PRECIP DOES MATERIALIZE
ACROSS OUR CWA LATER TONIGHT...STILL THINK WE HAVE A DECENT CHANCE
TO SEE SOME LIGHT AND BRIEF FROZEN/FREEZING PRECIP AT THE ONSET
GIVEN WET BULB COOLING AND LINGERING COLD NEAR-SFC TEMPS. FORECAST
SOUNDINGS FOR THE OVERNIGHT PERIOD DEPICT THE AFOREMENTIONED GRADUAL
WAA AND MOISTURE INCREASE FROM THE MID-LEVELS DOWN...YET THERE
REMAINS PLENTY OF DRY AIR BETWEEN 750-900 MB WHICH RESULTS IN WET
BULB TEMPS BELOW FREEZING FOR A SIGNIF LAYER BELOW 850MB. IF LIFT
WAS STRONGER AND PRECIP RATES HEAVIER...I WOULDN`T BE SURPRISED IF
WE EVEN SAW A QUICK P-TYPE TRANSITION FROM S TO IP TO FZRA THEN RAIN
WHILE THE COLUMN SATURATES AND WARMS. FOR NOW WILL KEEP LOW-END POPS
ACROSS OUR NORTHERN ZONES CLOSER TO THE TRIAD AND VA BORDER
BEGINNING AFT 3 AM. WHILE THE PRECIP RISK STILL LOOKS LOW...IF IT
INDEED EVOLVES...THERE WILL BE A CHANCE FOR A FEW LOCALIZED SLICK
SPOTS MONDAY MORNING AT THE ONSET...WHICH WOULD MAINLY IMPACT
ELEVATED SURFACES AND BRIDGES...BEFORE TEMPS RISE ABOVE FREEZING AFT
SUNRISE. WHILE CONFIDENCE IN PRECIP OCCURRING IS TOO LOW ATTM TO
WARRANT ANY SORT OF ADVISORIES...WILL CONTINUE TO MENTION IN THE HWO
THE POTENTIAL FOR LIGHT FZRA IF PRECIP DOES INDEED EVOLVE. EXPECT
LOWS FROM AROUND 30 NORTH TO LOWER 30S SOUTH.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...AS OF 310 AM SUNDAY...
MONDAY AND MONDAY NIGHT: THE CENTER OF ANOTHER ARCTIC HIGH...1033 MB
CENTERED NEAR CLEVELAND AT 07Z/27TH...WILL HAVE MODIFIED AND DRIFTED
OFF THE NC COAST BY MONDAY...THOUGH SIGNIFICANT LINGERING IN-SITU
COLD AIR DAMMING EFFECTS WILL REMAIN. AFTER THE EARLY MORNING
PRECIPITATION REFERENCED ABOVE...THIS IN-SITU WEDGE WILL MAINTAIN A
LOW OVERCAST AND EVEN SOME CONTINUED PATCHES OF DRIZZLE...WITH
TEMPERATURES WELL BELOW WHAT NWP WOULD SUGGEST. LOCAL THICKNESS/
TEMPERATURE RESEARCH THAT ACCOUNTS FOR CLOUD COVERAGE AND HEIGHT
SUGGESTS TEMPERATURES WILL HOLD IN THE 40S OVER THE PIEDMONT...TO
50-55 DEGREES ACROSS THE SOUTHERN TIER. WHILE SOME PARTIAL CLEARING
WILL BE POSSIBLE LATE IN THE DAY OVER THE SANDHILLS...THE STRATUS
LAYER WILL EXPAND AND LOWER...WITH AREAS OF DENSE FOG POSSIBLE...
SHORTLY AFTER NIGHTFALL. HIGHS 45 TO 55...WITH A MINIMAL DIURNAL
FALL INTO THE 39 TO 46 DEGREE RANGE OVERNIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 310 AM SUNDAY...
A PROGRESSIVE PATTERN ALOFT WILL BE IN TRANSITION FROM A PAIR OF
RIDGES ALONG EACH COAST...WITH A HIGHLY AMPLIFIED BUT PROGRESSIVE
TROUGH IN BETWEEN. THIS TROUGH WILL DRIVE A STRONG FRONTAL
ZONE...ONE FED BY STRONG MOISTURE TRANSPORT OFF THE GOM --
CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND 1.5 INCHES OR 2-3
SIGMAS ABOVE AVERAGE -- THROUGH THE EASTERN US/CENTRAL
NC WED-WED NIGHT. IT WILL TURN MILDER IN ADVANCE OF THE SYSTEM
TUE-WED...THOUGH THIS WARMING WILL BE TEMPERED OVER THE PIEDMONT BY
CONTINUED IN-SITU WEDGE INFLUENCE AND ASSOCIATED STRATUS MOISTURE
TRAPPED BY A STRONG SUBSIDENCE INVERSION ALOFT.
HIGHS TUE FROM AROUND 60 DEGREES NW TO AROUND 70 SE...THEN ABOUT A
CATEGORY MILDER IN A BREEZY SOUTHWESTERLY LOW LEVEL FLOW...BUT WITH
INCREASING DEEP LAYER MOISTURE/MULTI-LAYERED OVC...ON WED.
WIDESPREAD SOAKING SHOWERS WILL ACCOMPANY THE FRONTAL ZONE...WITH
PRECIPITATION AMOUNTS EXPECTED TO RANGE BETWEEN A HALF INCH AND ONE
INCH...HIGHEST OVER THE WESTERN PIEDMONT...WHERE FORCING FOR ASCENT
WILL BE MAXIMIZED BY THE LIFTING SOUTHERN PORTION OF THE TROUGH
ALOFT.
STRONG CAA BEHIND THE FRONT WILL RESULT IN TEMPERATURES THU ABOUT 20
DEGREES COOLER THAN THOSE OF WED. ANOTHER ARCTIC HIGH WILL HEAD
TOWARD OUR REGION FRI-SAT...LED SOUTHEASTWARD BY A CLIPPER-TYPE WAVE
AND ACCOMPANYING SURFACE COLD FRONT ON FRI. MODEL CROSS SECTIONS
INDICATE SUFFICIENT LIFT AND SATURATION TO GENERATE SNOW FROM THE
NORTHERN NC PIEDMONT NORTHWARD THROUGH VA...BUT A DEEP AND DRY
SUB-CLOUD LAYER SHOULD RESULT IN ONLY VIRGA OR A FEW FLURRIES NORTH
OF HIGHWAY 64 FRI MORNING...GIVEN THE EXPECTED S/W TRACK ACROSS
SOUTHERN VA. OPPOSED BY STRONG CAA AND A BRISK NORTHWESTERLY WIND ON
FRI...TEMPERATURES WILL STRUGGLE TO REACH 40 DEGREES ACROSS THE
NORTHERN PIEDMONT...TO UPPER 40S TOWARD THE SC LINE. THE CENTER OF
THE HIGH WILL DRIFT OVERHEAD BY SAT MORNING...WHICH SUGGESTS
EXCELLENT RADIATIONAL COOLING WILL BE LIKELY...HINDERED ONLY BY
CIRRUS ASSOCIATED WITH ANOTHER DISTURBANCE IN NW FLOW ALOFT.
PROJECTED LOW LEVEL THICKNESS VALUES AROUND 1370 METERS SAT MORNING
SUGGEST LOWS IN THE UPPER TEENS TO LOWER 20S...WITH HIGHS IN THE
LOWER TO MIDDLE 40S ON SAT.
&&
.AVIATION /12Z SUNDAY THROUGH WEDNESDAY/...
AS OF 645 AM SATURDAY...
A LARGE AREA OF FOG AND LOW CIGS CONTINUES EAST OF A N-S LINE FROM
KTDF-KTTA-KSOP...AND EXTENDING EASTWARD TO THE COASTAL PLAIN. FLT
CONDITIONS IN THIS AREA ARE GENERALLY IFR WITH SOME LOCALIZED LIFR
CONDITIONS. FORECAST SOUNDINGS SHOW THIS LIFTING AND DISSIPATING BY
15Z. OUTSIDE OF THE FOG/CIGS...VFR CONDITIONS. AFT 15Z EXPECT VFR
CONDITIONS THROUGH APPROX 06Z...WITH HIGH CLOUDS MOVING IN THIS
AFTERNOON AND LOWERING THROUGH THE EVENING AHEAD OF THE NEXT WEATHER
SYSTEM.
LATEST NAM/GFS RUNS HAVE COME IN WITH PERHAPS A LITTLE DEEPER
MOISTURE OVERNIGHT AS MID LEVEL WAA AND WEAK LIFT SETS UP ACROSS OUR
AREA...THUS INCREASING THE CONCERN THAT SOME LIGHT FROZEN/FREEZING
PRECIPITATION MAY OCCUR AFT 28/05Z. WHILE AMOUNTS ARE STILL PROGGED
TO BE VERY LIGHT...AREAS POTENTIALLY IMPACTED WOULD BE MAINLY ACROSS
THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN AND AFFECTING
KINT...KGSO...KRDU...AND TO A LESSER EXTENT KRWI. TEMPS ARE EXPECTED
TO RISE ABOVE FREEZING AFT SUNRISE MONDAY MORNING WITH IMPROVING
CONDITIONS. THEN EXPECT MVFR OR VFR CONDITIONS THE REST OF THE
MONDAY.
A BRIEF IMPROVEMENT IN AVIATION CONDITIONS EXPECTED TUESDAY THOUGH
IT WILL BECOME BREEZY A WITH SW WIND GUSTING 20-25 MPH IN THE
AFTERNOON. A STRONG COLD FRONT WILL APPROACH CENTRAL NC TUESDAY
NIGHT AND CROSS THE AREA LATE WEDNESDAY...BRINGING BREEZY CONDITIONS
AND SCATTERED SHOWERS WHICH MAY IMPACT FLT CONDITIONS. IMPROVING
CONDITIONS EXPECTED THU.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...NP
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
459 AM EST SUN JAN 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL LINGER OVER THE AREA TODAY BEFORE MOVING OFFSHORE
ON MONDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY
AND CROSS THE REGION WEDNESDAY NIGHT. HIGH PRESSURE WILL GRADUALLY BUILD
IN FROM THE NORTHWEST THURSDAY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 435 AM SUNDAY...LOW STRATUS CONTINUE TO MOVE ACROSS THE
AREA AND NOW COVERS MOSTLY THE SOUTHWESTERN HALF OF THE CWA. SOME
CLEARING IS NOW TAKING PLACE ACROSS THE FAR NORTHEASTERN COUNTIES.
SKY COVER FORECAST WILL REMAIN TRICKY THIS MORNING AS MOISTURE IS
TRAPPED BENEATH A STRONG LOW-LEVEL INVERSION. LATEST RAP OUTPUT SHOWS
MOST OF THE LOW CLOUDS DISSIPATING BY MID MORNING. THE DAY SHOULD
AVERAGE OUT AT PARTLY CLOUDY. HIGH TEMPERATURES WILL AGAIN BY
CHILLY WITH LOWER TO MIDDLE 40S AREA-WIDE AS AXIS OF COOL HIGH
PRESSURE RIDGE SETTLES OVER THE CAROLINAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
AS OF 435 AM SUNDAY...MID-LEVEL MOISTURE INCREASES FROM THE WEST
TONIGHT AS A WEAK SHORTWAVE EMBEDDED IN THE NORTHWEST FLOW ALOFT
MOVES ACROSS THE REGION. THE GFS SPITS OUT A BIT OF QPF OVER THE
FAR NORTHERN COUNTIES WHILE THE NAM12...CANADIAN AND ECMWF KEEP
ANY QPF TO THE NORTH OF OUR REGION THROUGH DAYBREAK MONDAY. WILL
CONTINUE TO KEEP THE CWA DRY BUT WILL INDICATE MID AND HIGH LEVEL
CLOUDINESS OVERNIGHT. THIS CLOUDINESS SHOULD HOLD MINIMUM
TEMPERATURES BETWEEN 30 AND 35 DEGREES FOR MOST AREAS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 3 AM SUN...A WEAK SHORTWAVE WILL RIDE OVER THE UPPER RIDGE MON
AND CROSS NORTH CAROLINA FROM W TO E MON AFTN AND MAY PRODUCE SOME
SPRINKLES OR LIGHT SHOWERS ACROSS NORTHERN SECTIONS...MAINLY NORTH
OF HWY 264. SOME UNCERTAINTY IN MAX TEMPS MON WITH CLOUDS AND PCPN
BRINGING EVAP COOLING ENHANCING IN-SITU DAMMING INLAND BUT SLY FLOW
TRIES TO DEVELOP AS HIGH PRES SLIDES OFF THE COAST. COULD SEE HIGHS
ONLY AROUND 50S FAR INLAND BUT APPROACHING 60 SRN COASTAL SECTIONS.
SURFACE RIDGE WILL REMAIN OFF THE COAST MON NIGHT...ALLOWING WINDS
TO VEER S-SW AND BRING DEWPOINTS BACK INTO THE 40S ACROSS THE REGION
WHICH COULD BRING AREAS OF FOG ACROSS THE REGION EARLY TUE.
GRADIENTS WILL TIGHTEN TUES/TUES NIGHT WITH RIDGE HOLDING STRONG OFF
THE COAST AND A STRONG UPPER LEVEL TROUGH WITH ATTENDANT SURFACE
COLD FRONT DIGGING ACROSS THE CENTRAL/SOUTHERN MISSISSIPPI VALLEY.
LOW LEVEL THICKNESSES INCREASE ABOUT 30M TUE WITH MAX TEMPS CLIMBING
INTO THE UPPER 60S TO LOW 70S INLAND AND LOW TO MID 60S ACROSS THE
OBX...WITH LOWS TUES NIGHT ONLY FALLING INTO THE 50S. STRONG WAA
PERSISTS ON WED WITH A STRENGTHENING LOW LEVEL JET BRINGING TEMPS
INTO THE LOW TO MID 70S INLAND TO MID 60S OBX. IT WON`T TAKE MUCH
MIXING TO BRING WIND GUSTS TO AROUND 30 MPH OR STRONGER WED
AFTERNOON WITH 40-50 KTS WINDS JUST 1000-2000FT AGL AND GRADIENT
WINDS COULD REACH WIND ADVISORY CRITERIA ALONG COASTAL SECTIONS.
THERE REMAINS SOME DIFFERENCES AMONG THE MODELS WITH THE TIMING OF
THE FRONT. THE GFS IS FASTEST BRINGING SHOWERS INTO THE REGION LATE
WED AFTERNOON AND THE FRONT ACROSS THE REGION WED EVENING WHILE THE
PREFERRED ECMWF IS SLOWER HOLDING THE HEAVIER PCPN OFF UNTIL WED
EVENING AND THE FRONT ACROSS THE REGION AFTER MIDNIGHT. KEPT MENTION
OF THUNDER OUT OF THE GRIDS THIS MORNING AS MODELS INDICATE LESS
THAN 100 J/KG CAPE THROUGH PEAK HEATING THOUGH STRONG UNIDIRECTIONAL
WIND SHEAR WILL BE IN PLACE AND COULD SEE STRONG WIND GUSTS IN
HEAVIER SHOWERS. THE SYSTEM WILL BE PUSHING ACROSS THE REGION FAIRLY
QUICKLY LIMITING THE AMOUNT OF QPF EXPECTED THOUGH WE COULD SEE A
QUICK 1/2 TO 3/4" WED NIGHT. TEMPS WILL LIKELY REMAIN IN THE 60S
MUCH OF WED NIGHT AHEAD OF THE FRONT AND ONLY DROPPING TO AROUND 50
BY DAYBREAK AFTER FROPA. CAA RAMPS UP EARLY THU AND EXPECT MAX TEMPS
TO OCCUR IN THE MORNING WITH HIGHS MAINLY IN THE M50S...THEN SLOWLY
DECREASE THROUGH THE AFTERNOON.
THURS/THURS NIGHT WILL SEE TEMPS BACK NEAR NORMAL WITH HIGHS IN THE
MID/UPPER 50S AND LOWS IN THE LOW/MID 30S. SHORTWAVE ENERGY WILL
ROTATE AROUND THE BASE OF A DIGGING UPPER TROUGH FRI WITH GUIDANCE
SUGGESTING PRECIP CLIPPING THE NE ZONES. HAVE POPS JUST BELOW SLIGHT
CHANCE FOR NOW GIVEN UNCERTAINTY IN THE EXTENDED. THE SHORTWAVE WILL
ALSO PROVIDE A REINFORCING SHOT OF COLD AIR TO THE REGION. LOW LEVEL
THICKNESSES AND 850 MB TEMPS FALL TO -9 TO -12C FRI AND EXPECT HIGHS
IN THE 40S. SURFACE RIDGE BUILDS SE ACROSS THE REGION SAT WITH ZONAL
FLOW ALOFT...AND TEMPS IN THE MID/UPPER 40S.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 1255 AM SUNDAY...BASED ON CURRENT SATELLITE IMAGERY AND
SURFACE OBSERVATIONS...WILL GO A BIT MORE NEGATIVE ON THE TAFS
THROUGH THE OVERNIGHT HOURS. WITH LOW LEVEL MOISTURE TRAPPED
BENEATH A STRONG INVERSION...THINK THE IFR/LIFR CEILINGS WILL
CONTINUE ALONG WITH PATCHES OF FOG. VFR WILL RETURN BY MORNING AS
COLUMN DRIES WITH GOOD MIXING TAKING PLACE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 330 AM SUN...A SHORTWAVE TROUGH RIDES OVER UPPER RIDGING
CENTERED OVER FLA MON WHICH COULD BRING LIGHT SHOWER WITH PERIODS OF
SUB VFR CONDITIONS ACROSS RTES...MAINLY NORTH OF US 264. SOUTH TO
SOUTHWEST FLOW BRINGS RISING DEWPOINTS MON NIGHT AND COULD SEE AREAS
OF FG/ST DEVELOP BRINGING IFR OR LOWER EARLY TUES. A STRONG COLD
FRONT APPROACHES TUES NIGHT AND WED WITH A STRENGTHENING LOW LEVEL
JET AND LOW LEVEL WIND SHEAR COULD BE AN ISSUE EARLY WED FOLLOWED BY
STRONG WIND SOUTH TO SOUTHWEST GUSTS UPWARDS OF 25-30 KTS WED
AFTERNOON. SOME TIMING DIFFERENCES WITH THE FRONT WED NIGHT BUT A
PERIOD OF HEAVY SHOWERS WITH STRONG WIND GUSTS AND SUB VFR
CONDITIONS LIKELY AHEAD OF THE FRONT. VFR CONDITIONS EXPECTED THU AS
CAA RAMPS UP BRINGING WEST WINDS GUSTING TO AROUND 20-25 KTS.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 440 AM SUNDAY...AREA OBSERVING PLATFORM SHOWING A BIT OF A
SURGE WORKING DOWN FROM THE NORTH WITH WINDS GENERALLY IN THE 15
TO 20 KNOT RANGE NORTH OF CAPE LOOKOUT AND OVER THE SOUNDS. SEAS
HAVE BUILT TO 7 FEET AT THE BUOY 13 MILES EAST OF OREGON INLET AS
OF 4 AM. HAVE EXTENDED THE SCA FOR THE CENTRAL WATERS THROUGH
ABOUT MIDDAY TO ALLOW TIME FOR THESE SEAS TO SUBSIDE AS THE
SURFACE RIDGE OF HIGH PRESSURE WORKS ITS WAY SOUTH. WINDS BECOMING
10 KNOTS OR LESS TONIGHT WITH THE RIDGE AXIS ALONG THE
CAROLINA/VIRGINIA COAST.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 330 AM SUN...SURFACE RIDGE WILL SHIFT OFFSHORE MON WITH WINDS
VEERING SOUTH TO SOUTHWEST AND INCREASING DURING THE AFTERNOON AS A
SYSTEM PASSES TO THE NORTH...PEAKING AROUND 10-20 KT MON NIGHT WHILE
SEAS BUILD TO 2-4 FT. SLIGHT SLACKENING OF THE WINDS TUE...GRADIENT
WILL INCREASE TUES NIGHT INTO WED AS A STRONG COLD FRONT APPROACHES
FROM THE WEST. MODELS IN GOOD AGREEMENT DEVELOPING STRONG SCA
CONDITIONS LATE WED AFTERNOON AND SEVERAL MODELS EVEN BRING A SHORT
WINDOW GALES JUST AHEAD OF THE FRONT WED EVENING. SOME SPECULATION
ON JUST HOW MUCH MIXING WILL OCCUR OVER THE COOLER NEAR SHORE WATERS
BUT GALES QUITE LIKELY NEAR THE GULF STREAM WITH A 60+ KT LOW LEVEL
JET IN PLACE. WAVEWATCH HIGHER WITH SEAS AS A RESULT OF STRONGER
WINDS AND BUILDS SEAS TO 8-12 FT WED AFTER NOON THROUGH WED NIGHT.
SLIGHT TIMING DIFFERENCES AMONG THE MODELS WITH FROPA WITH FASTER
MODELS BRINGING IT THROUGH WED EVENING THOUGH A MAJORITY OF MODEL
CONSENSUS PUSHING THE FRONT THROUGH AFTER MIDNIGHT. WINDS SHIFT TO
WEST TO NORTHWEST AFTER FROPA WITH WINDS AND SEAS GRADUALLY
SUBSIDING THROUGH THE DAY THURSDAY. WAVEWATCH DROPS SEAS BELOW 6 FT
AROUND MIDNIGHT THU NIGHT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR AMZ152-
154.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...SK
AVIATION...CTC/SK
MARINE...CTC/SK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EST SUN JAN 27 2013
.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL HOLD OVER THE AREA TODAY. AN UPPER
LEVEL DISTURBANCE WILL PASS NORTHEASTWARD THROUGH THE REGION TONIGHT
THROUGH MONDAY MORNING. THE SURFACE HIGH WILL MOVE OFF THE COAST
LATE MONDAY...FOLLOWED BY A WARM SOUTHWEST FLOW INTO THE REGION
THROUGH MIDWEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 310 AM SUNDAY...
THROUGH SUNRISE...THE MAIN CONCERN ARE THE PATCHES OF DENSE FOG THAT
HAVE DEVELOPED ACROSS PORTIONS OF OUR CWA INCLUDING THE TRIANGLE
REGION. WE SUSPECT THAT LINGERING GROUND MOISTURE AND PATCHES OF ICE
COVER FROM FRIDAYS STORM HAVE HELPED INITIATE THE DENSER PATCHES OF
FOG. NOTED THAT THE HRRR CAPTURED THIS FOG PRETTY WELL...AND SHOWS
IT CONTINUING THROUGH AROUND 12Z OR SO. GIVEN THE LIMITED NATURE OF
THE 1/4 MILE VSBY REPORTS...FOR NOW WE HAVE THIS COVERED WITH AN SPS
AND WILL MONITOR AS THE MORNING PROGRESSES.
FOR THE DAYTIME TODAY AFTER FOG BURNS OFF...EXPECT LOW-IMPACT
WEATHER AS THE S/W RIDGE CURRENTLY OVER THE MS VALLEY DRIFTS EAST
TOWARD US AND THE SFC RIDGE REMAINS OVER THE CAROLINAS. DESPITE
FORECAST SOUNDINGS DEPICTING A COOLER BL TODAY COMPARED TO
YESTERDAY`S OBSERVED SOUNDING...EXPECT MORE SUNSHINE THAN YESTERDAY
WHICH SHOULD HELP TEMPS CLIMB A FEW DEGREES HIGHER THAN YESTERDAY...
RESULTING IN HIGHS AROUND 40 NORTH TO 46 SOUTH.
FOR TONIGHT..THE MAIN CONCERN IS EVOLVING PRECIP POTENTIAL. THE
MIDLEVEL RIDGE AXIS IS PROGGED TO SET UP OVER THE SOUTHEAST AND WILL
INITIATE WAA ACROSS OUR AREA THAT WILL TAKE PLACE ABOVE THE
SHALLOW COOLER NEAR-SFC LAYER. MODELS ARE GENERALLY DEPICTING THE
MORE SIGNIFICANT SYNOP SCALE LIFT AND MOISTURE TRANSPORT OCCURRING
TO OUR NORTH CLOSER TO A S/W TROUGH THAT WILL BE MOVING ACROSS THE
MIDWEST REGION. THE GFS IS THE MOST GENEROUS REGARDING QPF ACROSS
OUR AREA OVERNIGHT...WHILE OTHER MODELS KEEP MOST IF NOT ALL OF THE
QPF NORTH OF THE VA/NC STATE LINE. IF LIGHT PRECIP DOES MATERIALIZE
ACROSS OUR CWA LATER TONIGHT...STILL THINK WE HAVE A DECENT CHANCE
TO SEE SOME LIGHT AND BRIEF FROZEN/FREEZING PRECIP AT THE ONSET
GIVEN WET BULB COOLING AND LINGERING COLD NEAR-SFC TEMPS. FORECAST
SOUNDINGS FOR THE OVERNIGHT PERIOD DEPICT THE AFOREMENTIONED GRADUAL
WAA AND MOISTURE INCREASE FROM THE MID-LEVELS DOWN...YET THERE
REMAINS PLENTY OF DRY AIR BETWEEN 750-900 MB WHICH RESULTS IN WET
BULB TEMPS BELOW FREEZING FOR A SIGNIF LAYER BELOW 850MB. IF LIFT
WAS STRONGER AND PRECIP RATES HEAVIER...I WOULDN`T BE SURPRISED IF
WE EVEN SAW A QUICK P-TYPE TRANSITION FROM S TO IP TO FZRA THEN RAIN
WHILE THE COLUMN SATURATES AND WARMS. FOR NOW WILL KEEP LOW-END POPS
ACROSS OUR NORTHERN ZONES CLOSER TO THE TRIAD AND VA BORDER
BEGINNING AFT 3 AM. WHILE THE PRECIP RISK STILL LOOKS LOW...IF IT
INDEED EVOLVES...THERE WILL BE A CHANCE FOR A FEW LOCALIZED SLICK
SPOTS MONDAY MORNING AT THE ONSET...WHICH WOULD MAINLY IMPACT
ELEVATED SURFACES AND BRIDGES...BEFORE TEMPS RISE ABOVE FREEZING AFT
SUNRISE. WHILE CONFIDENCE IN PRECIP OCCURRING IS TOO LOW ATTM TO
WARRANT ANY SORT OF ADVISORIES...WILL CONTINUE TO MENTION IN THE HWO
THE POTENTIAL FOR LIGHT FZRA IF PRECIP DOES INDEED EVOLVE. EXPECT
LOWS FROM AROUND 30 NORTH TO LOWER 30S SOUTH.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...AS OF 310 AM SUNDAY...
MONDAY AND MONDAY NIGHT: THE CENTER OF ANOTHER ARCTIC HIGH...1033 MB
CENTERED NEAR CLEVELAND AT 07Z/27TH...WILL HAVE MODIFIED AND DRIFTED
OFF THE NC COAST BY MONDAY...THOUGH SIGNIFICANT LINGERING IN-SITU
COLD AIR DAMMING EFFECTS WILL REMAIN. AFTER THE EARLY MORNING
PRECIPITATION REFERENCED ABOVE...THIS IN-SITU WEDGE WILL MAINTAIN A
LOW OVERCAST AND EVEN SOME CONTINUED PATCHES OF DRIZZLE...WITH
TEMPERATURES WELL BELOW WHAT NWP WOULD SUGGEST. LOCAL THICKNESS/
TEMPERATURE RESEARCH THAT ACCOUNTS FOR CLOUD COVERAGE AND HEIGHT
SUGGESTS TEMPERATURES WILL HOLD IN THE 40S OVER THE PIEDMONT...TO
50-55 DEGREES ACROSS THE SOUTHERN TIER. WHILE SOME PARTIAL CLEARING
WILL BE POSSIBLE LATE IN THE DAY OVER THE SANDHILLS...THE STRATUS
LAYER WILL EXPAND AND LOWER...WITH AREAS OF DENSE FOG POSSIBLE...
SHORTLY AFTER NIGHTFALL. HIGHS 45 TO 55...WITH A MINIMAL DIURNAL
FALL INTO THE 39 TO 46 DEGREE RANGE OVERNIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 310 AM SUNDAY...
A PROGRESSIVE PATTERN ALOFT WILL BE IN TRANSITION FROM A PAIR OF
RIDGES ALONG EACH COAST...WITH A HIGHLY AMPLIFIED BUT PROGRESSIVE
TROUGH IN BETWEEN. THIS TROUGH WILL DRIVE A STRONG FRONTAL
ZONE...ONE FED BY STRONG MOISTURE TRANSPORT OFF THE GOM --
CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND 1.5 INCHES OR 2-3
SIGMAS ABOVE AVERAGE -- THROUGH THE EASTERN US/CENTRAL
NC WED-WED NIGHT. IT WILL TURN MILDER IN ADVANCE OF THE SYSTEM
TUE-WED...THOUGH THIS WARMING WILL BE TEMPERED OVER THE PIEDMONT BY
CONTINUED IN-SITU WEDGE INFLUENCE AND ASSOCIATED STRATUS MOISTURE
TRAPPED BY A STRONG SUBSIDENCE INVERSION ALOFT.
HIGHS TUE FROM AROUND 60 DEGREES NW TO AROUND 70 SE...THEN ABOUT A
CATEGORY MILDER IN A BREEZY SOUTHWESTERLY LOW LEVEL FLOW...BUT WITH
INCREASING DEEP LAYER MOISTURE/MULTI-LAYERED OVC...ON WED.
WIDESPREAD SOAKING SHOWERS WILL ACCOMPANY THE FRONTAL ZONE...WITH
PRECIPITATION AMOUNTS EXPECTED TO RANGE BETWEEN A HALF INCH AND ONE
INCH...HIGHEST OVER THE WESTERN PIEDMONT...WHERE FORCING FOR ASCENT
WILL BE MAXIMIZED BY THE LIFTING SOUTHERN PORTION OF THE TROUGH
ALOFT.
STRONG CAA BEHIND THE FRONT WILL RESULT IN TEMPERATURES THU ABOUT 20
DEGREES COOLER THAN THOSE OF WED. ANOTHER ARCTIC HIGH WILL HEAD
TOWARD OUR REGION FRI-SAT...LED SOUTHEASTWARD BY A CLIPPER-TYPE WAVE
AND ACCOMPANYING SURFACE COLD FRONT ON FRI. MODEL CROSS SECTIONS
INDICATE SUFFICIENT LIFT AND SATURATION TO GENERATE SNOW FROM THE
NORTHERN NC PIEDMONT NORTHWARD THROUGH VA...BUT A DEEP AND DRY
SUB-CLOUD LAYER SHOULD RESULT IN ONLY VIRGA OR A FEW FLURRIES NORTH
OF HIGHWAY 64 FRI MORNING...GIVEN THE EXPECTED S/W TRACK ACROSS
SOUTHERN VA. OPPOSED BY STRONG CAA AND A BRISK NORTHWESTERLY WIND ON
FRI...TEMPERATURES WILL STRUGGLE TO REACH 40 DEGREES ACROSS THE
NORTHERN PIEDMONT...TO UPPER 40S TOWARD THE SC LINE. THE CENTER OF
THE HIGH WILL DRIFT OVERHEAD BY SAT MORNING...WHICH SUGGESTS
EXCELLENT RADIATIONAL COOLING WILL BE LIKELY...HINDERED ONLY BY
CIRRUS ASSOCIATED WITH ANOTHER DISTURBANCE IN NW FLOW ALOFT.
PROJECTED LOW LEVEL THICKNESS VALUES AROUND 1370 METERS SAT MORNING
SUGGEST LOWS IN THE UPPER TEENS TO LOWER 20S...WITH HIGHS IN THE
LOWER TO MIDDLE 40S ON SAT.
&&
.AVIATION /06Z SUNDAY THROUGH WEDNESDAY/...
AS OF 105 AM SATURDAY...
A LOCALIZED AREA OF DENSE FREEZING FOG WITH IFR/LIFR CONDITIONS
CONTINUES ATTM GENERALLY SOUTH OF A LINE FROM KHBI-KRDU-KLHZ FOR
ABOUT 40 MILES. SIMILAR CONDITIONS CURRENTLY EXIST ALONG AND EAST OF
THE I-95 CORRIDOR FROM NEAR KFAY TO THE NC/VA LINE. RAP FORECAST
SOUNDINGS SUGGEST THIS WILL CONTINUE THROUGH AT LEAST 10Z WITH
PERHAPS SOME MODEST IMPROVEMENT BETWEEN 10-14Z. OUTSIDE OF THIS
FOG...EXPECT VFR CONDITIONS. AFT 14Z...LOOK FOR VFR CONDITIONS
THROUGH THE REST OF THE TAF FORECAST PERIOD WITH PERHAPS SOME SCT CU
OR STRATOCU BETWEEN 3-5K FT THIS MORNING AND EARLY...THEN ADDITIONAL
HIGH CLOUDS LATE...AND WINDS AOB 10 KT.
A WEAK MID-UPPER DISTURBANCE WILL APPROACH AND CROSS THE REGION LATE
SUNDAY NIGHT INTO EARLY MONDAY. THIS SYSTEM AND THE AVAILABLE
MOISTURE IN THE ATMOSPHERE MAY TRIGGER A FEW PATCHES OF LIGHT
PRECIPITATION ACROSS THE NORTHERN PIEDMONT AND NORTHERN COASTAL
PLAIN. TEMPERATURES WILL BE CLOSE TO OR SLIGHTLY BELOW FREEZING...SO
POCKETS OF FREEZING RAIN OR FREEZING DRIZZLE MAY OCCUR. CONFIDENCE
LEVEL OF SEEING FREEZING PRECIPITATION IS ABOUT 33 PERCENT. IF
FREEZING PRECIPITATION WERE TO OCCUR...IT WOULD AFFECT THE TRIAD
TERMINALS AND POSSIBLY KRDU AND KRWI. OTHERWISE EXPECT MVFR CEILINGS
WITH THIS SYSTEM MONDAY INTO MONDAY NIGHT.
A BRIEF IMPROVEMENT IN AVIATION CONDITIONS EXPECTED TUESDAY THOUGH
IT WILL BECOME BREEZY A WITH SW WIND GUSTING 20-25 MPH IN THE
AFTERNOON. A STRONG COLD FRONT WILL APPROACH CENTRAL NC TUESDAY
NIGHT AND CROSS THE AREA LATE WEDNESDAY INTO WEDNESDAY NIGHT. EXPECT
CONTINUED BREEZY CONDITIONS AHEAD AND IMMEDIATELY BEHIND THE FRONT
WITH A CHANCE OF MVFR CEILINGS WED-WED NIGHT ALONG WITH SCATTERED
SHOWERS. IMPROVING WEATHER CONDITIONS ARE ANTICIPATED FOR THU...
THROUGH IT IS EXPECTED TO REMAIN BREEZY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...NP/WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
105 AM EST SUN JAN 27 2013
.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL HOLD OVER THE AREA THROUGH SUNDAY.
AN UPPER LEVEL DISTURBANCE WILL PASS NORTHEASTWARD THROUGH THE
REGION SUNDAY NIGHT THROUGH MONDAY MORNING. THE SURFACE HIGH WILL
MOVE OFF THE COAST LATE MONDAY... FOLLOWED BY A WARM SOUTHWEST FLOW
INTO THE REGION THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 925 PM SATURDAY...
THROUGH TONIGHT: INTERESTING FORECAST TONIGHT AS PATCHES OF FOG HAVE
DEVELOPED OVER THE STATE... WHILE TWO AREAS OF STRATUS -- ONE JUST
SW OF RALEIGH AND A LARGER ONE OVER THE INTERIOR CENTRAL/NRN COASTAL
AREA -- SLOWLY DRIFT TOWARD THE WEST WITHIN THE PREVAILING LIGHT
NEAR-SURFACE FLOW FROM THE ENE. THIS AFTERNOON`S LARGE-SCALE
COMPUTER MODELS DID NOT PICK UP ON THIS WELL AT ALL... BUT THE
RAPID-UPDATE FINE-SCALE MODELS SUCH AS THE HRRR ARE DEPICTING IT
FAIRLY WELL... SHOWING THE STRATUS OVER EASTERN NC CONTINUING TO
DRIFT WESTWARD THROUGH CENTRAL NC OVERNIGHT. THE NEW 12KM NAM RUN
SHOWS THE NEXT POINT OF CONCERN -- THE BATCH OF HIGHER-BASED CLOUDS
OVER EAST-CENTRAL VA -- ADVECTING SOUTHWARD OVERNIGHT AS THE SURFACE
HIGH -- LOCATED OVER NORTH CENTRAL OH AT 00Z -- DRIFT EASTWARD
TONIGHT AND NOSING MORE STRONGLY TO THE SSE INTO NC. WE`RE ALREADY
SEEING SOME LOWER SURFACE DEW POINTS STARTING TO WORK SOUTHWARD FROM
VA TOWARD NC... WHICH SHOULD LIMIT THE LIFETIME AND EXTEND OF FOG
THROUGH THE NIGHT... BUT NEVERTHELESS A FEW SPOTS WILL SEE VSBYS
UNDER A MILE FOR A COUPLE OF HOURS... EXACERBATED IN SPOTS BY THE
LINGERING MOIST GROUND AND REMAINING PATCHY SNOW/ICE/SLEET
ACCUMULATIONS... WITH GENERALLY LIGHT WINDS. HAVE ADDED THIS FOG TO
THE FORECAST... AS WELL AS BEEFING UP THE CLOUD COVER ESPECIALLY IN
THE EASTERN AND NORTHERN CWA. THE RISK OF BLACK ICE REMAINS TONIGHT
INTO SUNDAY MORNING AS TEMPS WILL BOTTOM OUT BELOW FREEZING TOWARD
MORNING. DESPITE SLIPPING DEW POINTS LATE TONIGHT... WITH CLOUDS IN
PLAY... HAVE NUDGED LOWS UPWARD SLIGHTLY TO 23-28. -GIH
SUNDAY...S/W RIDGE DRIFTS EWD ACROSS THE LOWER OH AND TN VALLEYS.
THIS FEATURE WILL MAINTAIN A SURFACE RIDGE ACROSS THE CAROLINAS. THE
AIR MASS ASSOCIATED WITH THE SURFACE RIDGE WILL SLOWLY MODIFY.
THUS...SHOULD SEE AFTERNOON TEMPS ABOUT 3-4 DEGREES WARMER THAN
CURRENT AFTERNOON TEMPS. MAX TEMPS SUNDAY IN THE LOW-MID 40S.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 305 PM SATURDAY...
SUNDAY NIGHT...SURFACE RIDGE AXIS SLIDES SE...PLACING CENTRAL NC IN
THE RETURN FLOW SIDE OF THE HIGH...INITIATING A LOW LEVEL WARM AIR
ADVECTION REGIME. W-SW FLOW ALOFT WILL ADVECT MOISTURE INTO THE
REGION...AHEAD OF AN UPPER LEVEL LOW PRESSURE SYSTEM THAT WILL SKIRT
WELL W-NW OF OUR REGION. THUS ANTICIPATE INCREASING CLOUDINESS
SUNDAY NIGHT. MODEL GUIDANCE CONTINUES TO PAINT PATCHY PRECIP ACROSS
MAINLY THE NW AND FAR NORTHERN SECTION OF THE CWA OVERNIGHT SUNDAY
NIGHT THROUGH MID MORNING MONDAY. MODEL LIFT RATHER ANEMIC
THOUGH...MAINLY CENTERED ALOFT. ATMOSPHERE BELOW
WHILE AIR MASS ABOVE 4000FT WILL UNDERGO DECENT WARMING...AIR MASS
NEAR THE SURFACE WILL STILL RETAIN SOME OF ITS RESIDUAL COOL DRY
AIR. SURFACE WET BULB TEMPS REMAIN BELOW FREEZING THROUGH 12Z
MONDAY. THUS...WHAT PRECIP FALLS THROUGH THE COLUMN WILL LEAD TO
SOME COOLING OF THE TEMP PROFILE NEAR THE SURFACE. MODEL TEMP
PROFILE AND PARTIAL THICKNESSES SUGGEST MAIN P-TYPE FZRA AND/OR
RAIN. EVEN IF FZRA/FZDZ WERE TO OCCUR...IT WILL BE SPOTTY AND VERY
LIGHT IN NATURE DUE TO LACK OF ORGANIZED LIFT IN THE LOW-MID LEVELS.
THUS NOT ANTICIPATING WIDESPREAD TRAVEL ISSUES EARLY MONDAY MORNING
BUT CANNOT RULE OUT THE POTENTIAL FOR A SLICK BRIDGE OR TWO. IF/WHEN
IT BECOMES MORE CERTAIN PATCHY FZRA/FZDZ WILL OCCUR...A WINTER
WEATHER ADVISORY MAY BE NECESSARY. MIN TEMPS NEAR 30 TO THE LOWER
30S. -WSS
MONDAY AND MONDAY NIGHT: THE CENTER OF ANOTHER ARCTIC HIGH...1030 MB
CENTERED NEAR CHICAGO AT 19Z/26TH...WILL HAVE MODIFIED AND DRIFTED
OFF THE NC COAST BY MONDAY...THOUGH THE LINGERING IN-SITU CAD
EFFECTS WILL REMAIN. AFTER THE EARLY MORNING PRECIPITATION
REFERENCED ABOVE...THIS IN-SITU WEDGE WILL MAINTAIN A LOW
OVERCAST...WITH TEMPERATURES AOB WHAT NWP WOULD SUGGEST. WHILE SOME
PARTIAL CLEARING WILL BE POSSIBLE LATE IN THE DAY OVER THE
SANDHILLS...LOW STRATUS AND FOG - SOME DENSE - WILL ENVELOP CENTRAL
NC SHORTLY AFTER NIGHTFALL. HIGHS 45 TO 55...WITH A MINIMAL DIURNAL
FALL INTO THE 39 TO 46 DEGREE RANGE OVERNIGHT. -MWS
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 245 PM SATURDAY...
A PROGRESSIVE PATTERN ALOFT WILL BE IN TRANSITION FROM A PAIR OF
RIDGES ALONG EACH COAST...WITH A HIGHLY AMPLIFIED BUT PROGRESSIVE
TROUGH IN BETWEEN. THIS TROUGH WILL DRIVE A STRONG FRONTAL
ZONE...ONE FED BY STRONG MOISTURE TRANSPORT OFF THE GOM...THROUGH
THE EASTERN US/CENTRAL NC WED-WED NIGHT. IT WILL ACCORDINGLY TURN
QUITE MILD IN ADVANCE OF THE SYSTEM ON TUE...THOUGH TEMPERED A BIT
OVER THE PIEDMONT WHERE STRATUS AND FOG WILL BE SLOW TO LIFT AND
SCATTER. THIS STRATUS MOISTURE WILL BE TRAPPED BY A STRONG
SUBSIDENCE INVERSION ALOFT AND RESULT IN RENEWED STRATUS DEVELOPMENT
OVERNIGHT TUE...WITH TEMPERATURES APT TO RISE OVERNIGHT FROM LATE
EVENING LOWS IN THE LOWER 50S ON AVERAGE.
MILDER YET...TO WARM ON WED...IN STRONG SOUTHWESTERLY FLOW IN
ADVANCE OF THE AFOREMENTIONED FRONTAL ZONE...WITH HIGHS WITHIN 5
DEGREES OF 70 WEST TO EAST. WIDESPREAD SOAKING SHOWERS WILL
ACCOMPANY THE FRONTAL ZONE...WITH PRECIPITATION AMOUNTS EXPECTED TO
RANGE FROM A THIRD OF AN INCH OVER THE COASTAL PLAIN TO THREE
QUARTERS OF AN INCH OR SO OVER THE WESTERN PIEDMONT.
STRONG CAA BEHIND THE FRONT WILL RESULT IN TEMPERATURES THU ABOUT 20
DEGREES COOLER THAN THOSE OF WED. ANOTHER ARCTIC HIGH WILL HEAD
TOWARD OUR REGION FRI-SAT...LED SOUTHEASTWARD BY A CLIPPER-TYPE
WAVE AND ACCOMPANYING SURFACE COLD FRONT ON FRI. OPPOSED BY STRONG
CAA AND A BRISK NORTHWESTERLY WIND ON FRI...TEMPERATURES WILL
STRUGGLE TO REACH 40 DEGREES ACROSS THE NORTHERN PIEDMONT...TO UPPER
40S TOWARD THE SC LINE. THE CENTER OF THE HIGH WILL DRIFT OVERHEAD
BY SAT MORNING...WHICH SUGGESTS A GOOD PROBABILITY OF GOOD
RADIATIONAL COOLING CONDITIONS. HOWEVER...MEDIUM RANGE GUIDANCE DOES
INDICATE A S/W TROUGH ALOFT AND ACCOMPANYING CIRRUS SHIELD MAY
OVERSPREAD THE MIDDLE ATLANTIC REGION AT THAT TIME...SO WILL NOT
FORECAST - YET - THE UPPER TEENS THAT PROJECTED LOW LEVEL
THICKNESSES WOULD SUGGEST.
&&
.AVIATION /06Z SUNDAY THROUGH WEDNESDAY/...
AS OF 105 AM SATURDAY...
A LOCALIZED AREA OF DENSE FREEZING FOG WITH IFR/LIFR CONDITIONS
CONTINUES ATTM GENERALLY SOUTH OF A LINE FROM KHBI-KRDU-KLHZ FOR
ABOUT 40 MILES. SIMILAR CONDITIONS CURRENTLY EXIST ALONG AND EAST OF
THE I-95 CORRIDOR FROM NEAR KFAY TO THE NC/VA LINE. RAP FORECAST
SOUNDINGS SUGGEST THIS WILL CONTINUE THROUGH AT LEAST 10Z WITH
PERHAPS SOME MODEST IMPROVEMENT BETWEEN 10-14Z. OUTSIDE OF THIS
FOG...EXPECT VFR CONDITIONS. AFT 14Z...LOOK FOR VFR CONDITIONS
THROUGH THE REST OF THE TAF FORECAST PERIOD WITH PERHAPS SOME SCT CU
OR STRATOCU BETWEEN 3-5K FT THIS MORNING AND EARLY...THEN ADDITIONAL
HIGH CLOUDS LATE...AND WINDS AOB 10 KT.
A WEAK MID-UPPER DISTURBANCE WILL APPROACH AND CROSS THE REGION LATE
SUNDAY NIGHT INTO EARLY MONDAY. THIS SYSTEM AND THE AVAILABLE
MOISTURE IN THE ATMOSPHERE MAY TRIGGER A FEW PATCHES OF LIGHT
PRECIPITATION ACROSS THE NORTHERN PIEDMONT AND NORTHERN COASTAL
PLAIN. TEMPERATURES WILL BE CLOSE TO OR SLIGHTLY BELOW FREEZING...SO
POCKETS OF FREEZING RAIN OR FREEZING DRIZZLE MAY OCCUR. CONFIDENCE
LEVEL OF SEEING FREEZING PRECIPITATION IS ABOUT 33 PERCENT. IF
FREEZING PRECIPITATION WERE TO OCCUR...IT WOULD AFFECT THE TRIAD
TERMINALS AND POSSIBLY KRDU AND KRWI. OTHERWISE EXPECT MVFR CEILINGS
WITH THIS SYSTEM MONDAY INTO MONDAY NIGHT.
A BRIEF IMPROVEMENT IN AVIATION CONDITIONS EXPECTED TUESDAY THOUGH
IT WILL BECOME BREEZY A WITH SW WIND GUSTING 20-25 MPH IN THE
AFTERNOON. A STRONG COLD FRONT WILL APPROACH CENTRAL NC TUESDAY
NIGHT AND CROSS THE AREA LATE WEDNESDAY INTO WEDNESDAY NIGHT. EXPECT
CONTINUED BREEZY CONDITIONS AHEAD AND IMMEDIATELY BEHIND THE FRONT
WITH A CHANCE OF MVFR CEILINGS WED-WED NIGHT ALONG WITH SCATTERED
SHOWERS. IMPROVING WEATHER CONDITIONS ARE ANTICIPATED FOR THU...
THROUGH IT IS EXPECTED TO REMAIN BREEZY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS/MWS
LONG TERM...MWS
AVIATION...NP/WSS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1256 AM EST SUN JAN 27 2013
.SYNOPSIS...
STRONG HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST TONIGHT AND
SUNDAY...THEN SLIDE OFFSHORE MONDAY AND TUESDAY. A COLD FRONT WILL
APPROACH FROM THE WEST WEDNESDAY AND CROSS THE REGION WEDNESDAY
NIGHT. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE NORTHWEST
THURSDAY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1245 AM SUNDAY...LATEST 11-3.9 MICRON SATELLITE IMAGERY
SHOWS WIDESPREAD LOW STRATUS CONTINUE TO ADVECT AND GROW OVER MOST
OF EASTERN NORTH CAROLINA WITH SHALLOW MOISTURE TRAPPED BENEATH
STRONG INVERSION. THE LATEST RAP HAS A DECENT HANDLE ON THIS CLOUD
COVER AND WILL INCREASE CLOUDS TO BE A MOSTLY OVERCAST NIGHT. NO
OTHER MAJOR CHANGES TO THE CURRENT FORECAST AT THIS TIME.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
AS OF 225 PM SAT...MOSTLY SUNNY SKIES EXPECTED SUNDAY AS THE STRONG
HIGH PRES BUILDS SE AND ACROSS THE REGION LATE. CONT N/NE LOW LVL
FLOW WILL KEEP TEMPS BELOW NORMAL WITH HIGHS RANGING FROM AROUND
40 NE CST TO MID/POSS A FEW UPR 40S SW.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 3 PM SAT...SURFACE RIDGE WILL SHIFT OFFSHORE SUN NIGHT WITH
WINDS SHIFTING TO SE BY SUNRISE. A WEAK SHORTWAVE WILL RIDE OVER
THE UPPER RIDGE MON AND CROSS NORTH CAROLINA FROM W TO E MON AFTN
AND MAY PRODUCE SOME SPRINKLES ACROSS NORTHERN SECTIONS. HAVE
INTRODUCED SLIGHT CHANCE POPS FOR AREAS ALONG AND NORTH OF HWY 64.
UPPER RIDGE CENTERED OVER FLORIDA WILL PERSIST INTO TUES NIGHT.
TEMPS WILL BE NEAR CLIMO SUN NIGHT INTO MON...LOWS IN THE LOW 30S
INLAND TO LOW 40S OBX...AND HIGHS IN THE MID 50S. SURFACE RIDGE
WILL REMAIN OFF THE COAST MON AND MON NIGHT...ALLOWING WINDS TO
VEER S-SW AND BRING DEWPOINTS BACK INTO THE 40S ACROSS THE REGION.
GRADIENT WILL TIGHTEN TUES/TUES NIGHT WITH RIDGE HOLDING STRONG
OFF THE COAST AND A STRONG UPPER LEVEL TROUGH AND ASSOCIATED
SURFACE COLD FRONT DIGGING PUSHING EAST INTO THE CENTRAL/SOUTHERN
MISSISSIPPI VALLEY. HIGHS TUES WILL BUILD INTO THE LOW 70S INLAND
TO NEAR 60 ACROSS THE OBX...WITH LOWS TUES NIGHT ONLY FALLING INTO
THE 50S. SW SURFACE FLOW WILL PERSIST ON WED WITH HIGHS AGAIN IN
THE 70S WITH DEWPOINTS BUILDING INTO THE LOW/MID 50S.
A STRONG COLD FRONT WILL PUSH EAST THROUGH EASTERN NC ON WED NIGHT
INTO THURS MORNING. AT THIS TIME...INSTABILITY LOOKS TO REMAIN
WELL OFFSHORE AND HAVE REMOVED MENTION OF THUNDER WITH THIS
FORECAST PACKAGE. HAVE INCREASED POPS TO 50 PERCENT WED NIGHT
GIVEN GOOD MODEL AGREEMENT BETWEEN LATEST MEDIUM RANGE GUIDANCE.
WITH THE COLD FRONT CROSSING EARLY THURS MORNING...EXPECT MAX
TEMPS TO OCCUR IN THE MORNING AND SLOWLY DECREASE AS THE DAY
PROGRESSES DUE TO STRONG WNW CAA. THURS/THURS NIGHT WILL SEE
TEMPS BACK NEAR NORMAL WITH HIGHS IN THE MID/UPPER 50S AND LOWS
IN THE LOW/MID 30S. SHORTWAVE ENERGY WILL ROTATE AROUND THE BASE
OF A DIGGING UPPER TROUGH FRI WITH GUIDANCE SUGGESTING PRECIP
CLIPPING THE NE ZONES. HAVE POPS JUST BELOW SLIGHT CHANCE FOR NOW
GIVEN UNCERTAINTY IN THE EXTENDED. THE SHORTWAVE WILL ALSO PROVIDE
A REINFORCING SHOT OF COLD AIR TO THE REGION. LOW LEVEL THICKNESSES
AND 850 MB TEMPS FALL TO -9 TO -12C FRI AND WENT WITH BLEND
BETWEEN MEX/ECMWF MOS WITH HIGHS IN THE UPPER 40S TO LOW 50S SOUTH
TO LOW 40S NORTH...ALTHOUGH THESE TEMPS MAY BE TOO WARM AND MAY BE
REDUCED 4-5F WITH LATER FORECAST PACKAGES. SURFACE RIDGE BUILDS
SE ACROSS THE REGION SAT WITH ZONAL FLOW ALOFT...AND TEMPS IN THE
MID/UPPER 40S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH SUNDAY/...
AS OF 1255 AM SUNDAY...BASED ON CURRENT SATELLITE IMAGERY AND
SURFACE OBSERVATIONS...WILL GO A BIT MORE NEGATIVE ON THE TAFS
THROUGH THE OVERNIGHT HOURS. WITH LOW LEVEL MOISTURE TRAPPED
BENEATH A STRONG INVERSION...THINK THE IFR/LIFR CEILINGS WILL
CONTINUE ALONG WITH PATCHES OF FOG. VFR WILL RETURN BY MORNING
AS COLUMN DRIES WITH GOOD MIXING TAKING PLACE.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 315 PM SAT...MAINLY VFR CONDITIONS EXPECTED THROUGH WED.
BOUNDARY LAYER BEGINS TO MOISTEN TUES AS WINDS SHIFT S/SW. CANNOT
RULE OUT EARLY MORNING FOG ACROSS TAF SITES SHOULD WINDS SUFFICIENTLY
DECOUPLE. SW WINDS WILL GUST UPWARDS OF 20-25 KTS WED AFTERNOON.
A STRONG COLD FRONT WILL CROSS THE REGION WED NIGHT INTO THURS.
MAY SEE REDUCED VSBYS/CEILINGS WITH THE FRONTAL PASSAGE.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/
AS OF 1255 AM SUNDAY...FIRST SIGNS ON CAA SURGE SHOWING UP AT THE
CHESAPEAKE LIGHT WITH WINDS GUSTING TO 20 KNOTS. PER PREVIOUS
FORECAST...COULD SEE A PERIOD OF 6 FOOT SEAS OVER THE OUTER
PERIPHERY OF THE CENTRAL MARINE ZONES THROUGH THE EARLY MORNING
HOURS AS THE AREA OF PRESSURE RISES WORKS TO THE SOUTH. AS THE
CENTER OF THE HIGH BUILDS CLOSER SUNDAY NE WINDS WILL GRAD
DIMINISH AND SHLD BE IN THE 5 TO 10 KT RANGE BY EVENING. SEAS WILL
SUBSIDE TO 2 TO 4 FT SUN AFTN.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 315 PM SAT...SURFACE RIDGE WILL SHIFT OFFSHORE MON WITH WINDS
VEERING SOUTH TO SOUTHWEST BUT WITH SPEEDS 10 KNOTS OR LESS. SEAS
WILL BE 1-3 FT THROUGH TUES. GRADIENT WILL INCREASE LATE TUES
INTO WED BETWEEN HIGH OFFSHORE AND COLD FRONT APPROACHING FROM THE
WEST. SW WINDS WILL BUILD TO 20-25 KT LATE WED WITH THE FRONTAL
PASSAGE. SEAS WILL BUILD 3-5 FT TUES NIGHT THEN 5-8 FT WED/THURS.
EXPECT SCA HEADLINES WILL BE NEEDED FOR INCREASED WINDS AND SEAS
WED THROUGH THURS. ONLY MINOR ADJUSTMENTS TO LATEST WAVEWATCH III
GUIDANCE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ152-
154.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/RF/DAG
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
924 AM CST SUN JAN 27 2013
.UPDATE...
THE WARM FRONT IS NOW LIFTING ACROSS I-20/I-30 CORRIDORS AND
SHOULD PUSH ACROSS THE RED RIVER INTO SOUTHERN OKLAHOMA BY MIDDAY.
SOUTH AND SOUTHEAST WINDS ALREADY INCREASING TO 10-15 MPH WITH
MIXING AND STRONG WAA ALREADY OCCURRING. WE EXPECT LINGERING AND
LOCALIZED DENSE FOG ACROSS THE NORTHEAST COUNTIES TO QUICKLY
IMPROVE IN THE NEXT 1-2 HRS. THE DENSE FOG ADVISORY HAS BEEN
ALLOWED TO EXPIRE AT 9 AM WITH ANY REMAINING DENSE FOG BEING
LOCALIZED AND NOT WIDESPREAD.
ALOFT...A SHORTWAVE IS RIDING OVERHEAD AT THE MOMENT...BUT A STOUT
AND VERY DRY CAPPING INVERSION/ELEVATED MIXED LAYER BETWEEN 900-650MB
SHOULD KEEP ANY RAINFALL IN THE FORM OF ISOLATED/LIGHT SPRINKLES
THROUGH THIS MORNING. SOME PARTIAL SUNSHINE IS EXPECTED TO ARRIVE
FROM WEST TO EAST THROUGH THE AFTERNOON HOURS IN WAKE OF THIS
DISTURBANCE AS SUBSIDENCE ENSUES. THE LOW LEVEL WAA AND BREEZY
SOUTH WINDS WILL HELP TEMPERATURES WARM INTO THE LOWER 70S MANY
AREAS THIS AFTERNOON.
05/
&&
.AVIATION...
TIMING END OF VLIFR CONDITIONS PRESENTS THE MAIN FORECAST
CHALLENGE. AS WARM FRONT CONTINUES TO MOVE NORTH...EXPECT SOUTH
WINDS TO INCREASE NEAR OR AFTER SUNRISE AND VISIBILITIES SHOULD
IMPROVE FIRST. FWS VAD WINDS HAVE SHOWN LITTLE CHANGE SO FAR THIS
MORNING...WITH ONLY A SLIGHT VEERING OF THE 1K FT WINDS. LATEST
HRRR AND RAP MODELS FORECAST METROPLEX SFC WINDS TO INCREASE NEAR
13Z/14Z TIME FRAME...AND ALSO SHOW CEILINGS IMPROVING TO IFR NEAR
15Z SO TAFS REFLECT THAT TREND. INCREASING VISIBILITIES IN THE
SOUTH ADDS SOME CONFIDENCE TO THIS FORECAST. TONIGHT...SFC WIND
SHOULD STAY ABOVE 10 KT...AND VISIBILITIES SHOULD REMAIN HIGHER
THAN THIS MORNING EVEN THOUGH CEILINGS WILL DROP TO MVFR AND
POSSIBLY IFR.
WACO VISIBILITY HAS ALREADY IMPROVED AS DEW POINTS HAVE CLIMBED
INTO THE MID 50S...BUT CEILINGS WILL REMAIN LOW UNTIL AFTER
SUNRISE AS WELL.
&&
.PREV DISCUSSION... /ISSUED 308 AM CST SUN JAN 27 2013/
AREAS OF FOG WILL CONTINUE ACROSS NEARLY ALL OF NORTH TEXAS
THROUGH SUNRISE AS WARM/MOIST AIR MOVES OVER RELATIVELY COOL
GROUND. THE FOG WILL BE DENSE AT TIMES SO WE WILL KEEP A DENSE FOG
ADVISORY IN PLACE FOR ALL BUT THE EXTREME SOUTHERN COUNTIES.
EXPECT VISIBILITIES TO SLOWLY IMPROVE AFTER SUNRISE AND ALL SITES
SHOULD BE ABOVE 1/4 MILE VISIBILITY BY 9 AM. A MOSTLY CLOUDY...WARM
AND HUMID DAY IS IN STORE FOR NORTH TEXAS AS LOW LEVEL WARM AIR
ADVECTION INCREASES IN RESPONSE TO A DEEPENING HIGH PLAINS SURFACE
TROUGH. A FEW SPRINKLES OR VERY LIGHT SHOWERS ARE ALSO POSSIBLE
TODAY BUT MEASURABLE RAINFALL IS UNLIKELY.
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE ACROSS THE REGION
TONIGHT AND RESULT IN A WARM NIGHT WITH AREAS OF FOG. THE FOG
SHOULD NOT BE AS DENSE TONIGHT/MONDAY MORNING SINCE SOUTHERLY
WINDS WILL BE IN THE 10 TO 15 MPH RANGE.
MONDAY WILL BE MOSTLY CLOUDY...WARM AND HUMID AS LOW LEVEL WARM
AIR ADVECTION CONTINUES AHEAD OF AN APPROACHING UPPER LEVEL
TROUGH. AFTERNOONS HIGHS WILL BE IN THE MID 70S TO AROUND 80.
LARGE SCALE LIFT ASSOCIATED WITH THE APPROACHING UPPER TROUGH WILL
NOT INCREASE UNTIL MONDAY NIGHT. SOME WARM AIR ADVECTION SHOWERS
WILL BE POSSIBLE MONDAY NIGHT...BUT THE BEST RAIN AND
THUNDERSTORM CHANCES WILL NOT BEGIN UNTIL TUESDAY. IT APPEARS THAT
THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD OF A DRY LINE TUESDAY
WITH SOME STRONG TO SEVERE STORMS POSSIBLE DUE TO AMPLE SHEAR/
MODERATE INSTABILITY AND FORCING. STORMS SHOULD BE LINEAR IN
NATURE AND SHOULD END QUICKLY FROM WEST TO EAST TUESDAY
AFTERNOON/EVENING. CONFIDENCE CONTINUES TO INCREASE REGARDING THE
MOVEMENT OF THE UPPER TROUGH/DRY LINE AND ALL MODELS EXCEPT THE
NAM ARE IN VERY GOOD AGREEMENT. THEREFORE...CHANCE TO LIKELY POPS
ARE WARRANTED AT THIS TIME.
THE UPPER TROUGH AXIS IS PROGGED TO MOVE EAST OF THE REGION BY
WEDNESDAY MORNING WITH DRY NORTHWEST TO WEST FLOW EXPECTED THE
REMAINDER OF THE WEEK THROUGH THE WEEKEND. IT WILL BE COOLER AND
DRIER WEDNESDAY THROUGH SATURDAY WITH HIGHS MAINLY IN THE 50S AND
60S AND LOWS GENERALLY IN THE 30S AND 40S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 73 61 75 63 76 / 10 10 10 20 50
WACO, TX 74 63 76 63 76 / 10 10 10 20 50
PARIS, TX 69 61 75 60 76 / 10 10 10 20 60
DENTON, TX 72 61 75 61 75 / 10 10 10 20 50
MCKINNEY, TX 71 64 74 62 76 / 10 10 10 20 50
DALLAS, TX 73 64 76 63 76 / 10 10 10 20 50
TERRELL, TX 73 64 75 63 75 / 10 10 10 20 60
CORSICANA, TX 74 63 77 62 75 / 10 10 10 20 50
TEMPLE, TX 74 62 76 63 76 / 10 10 10 20 40
MINERAL WELLS, TX 74 57 76 60 72 / 10 10 10 20 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
84/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
434 AM CST SUN JAN 27 2013
.AVIATION...
TIMING END OF VLIFR CONDITIONS PRESENTS THE MAIN FORECAST
CHALLENGE. AS WARM FRONT CONTINUES TO MOVE NORTH...EXPECT SOUTH
WINDS TO INCREASE NEAR OR AFTER SUNRISE AND VISIBILITIES SHOULD
IMPROVE FIRST. FWS VAD WINDS HAVE SHOWN LITTLE CHANGE SO FAR THIS
MORNING...WITH ONLY A SLIGHT VEERING OF THE 1K FT WINDS. LATEST
HRRR AND RAP MODELS FORECAST METROPLEX SFC WINDS TO INCREASE NEAR
13Z/14Z TIME FRAME...AND ALSO SHOW CEILINGS IMPROVING TO IFR NEAR
15Z SO TAFS REFLECT THAT TREND. INCREASING VISIBILITIES IN THE
SOUTH ADDS SOME CONFIDENCE TO THIS FORECAST. TONIGHT...SFC WIND
SHOULD STAY ABOVE 10 KT...AND VISIBILITIES SHOULD REMAIN HIGHER
THAN THIS MORNING EVEN THOUGH CEILINGS WILL DROP TO MVFR AND
POSSIBLY IFR.
WACO VISIBILITY HAS ALREADY IMPROVED AS DEW POINTS HAVE CLIMBED
INTO THE MID 50S...BUT CEILINGS WILL REMAIN LOW UNTIL AFTER
SUNRISE AS WELL.
&&
.PREV DISCUSSION... /ISSUED 308 AM CST SUN JAN 27 2013/
AREAS OF FOG WILL CONTINUE ACROSS NEARLY ALL OF NORTH TEXAS
THROUGH SUNRISE AS WARM/MOIST AIR MOVES OVER RELATIVELY COOL
GROUND. THE FOG WILL BE DENSE AT TIMES SO WE WILL KEEP A DENSE FOG
ADVISORY IN PLACE FOR ALL BUT THE EXTREME SOUTHERN COUNTIES.
EXPECT VISIBILITIES TO SLOWLY IMPROVE AFTER SUNRISE AND ALL SITES
SHOULD BE ABOVE 1/4 MILE VISIBILITY BY 9 AM. A MOSTLY CLOUDY...WARM
AND HUMID DAY IS IN STORE FOR NORTH TEXAS AS LOW LEVEL WARM AIR
ADVECTION INCREASES IN RESPONSE TO A DEEPENING HIGH PLAINS SURFACE
TROUGH. A FEW SPRINKLES OR VERY LIGHT SHOWERS ARE ALSO POSSIBLE
TODAY BUT MEASURABLE RAINFALL IS UNLIKELY.
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE ACROSS THE REGION
TONIGHT AND RESULT IN A WARM NIGHT WITH AREAS OF FOG. THE FOG
SHOULD NOT BE AS DENSE TONIGHT/MONDAY MORNING SINCE SOUTHERLY
WINDS WILL BE IN THE 10 TO 15 MPH RANGE.
MONDAY WILL BE MOSTLY CLOUDY...WARM AND HUMID AS LOW LEVEL WARM
AIR ADVECTION CONTINUES AHEAD OF AN APPROACHING UPPER LEVEL
TROUGH. AFTERNOONS HIGHS WILL BE IN THE MID 70S TO AROUND 80.
LARGE SCALE LIFT ASSOCIATED WITH THE APPROACHING UPPER TROUGH WILL
NOT INCREASE UNTIL MONDAY NIGHT. SOME WARM AIR ADVECTION SHOWERS
WILL BE POSSIBLE MONDAY NIGHT...BUT THE BEST RAIN AND
THUNDERSTORM CHANCES WILL NOT BEGIN UNTIL TUESDAY. IT APPEARS THAT
THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD OF A DRY LINE TUESDAY
WITH SOME STRONG TO SEVERE STORMS POSSIBLE DUE TO AMPLE SHEAR/
MODERATE INSTABILITY AND FORCING. STORMS SHOULD BE LINEAR IN
NATURE AND SHOULD END QUICKLY FROM WEST TO EAST TUESDAY
AFTERNOON/EVENING. CONFIDENCE CONTINUES TO INCREASE REGARDING THE
MOVEMENT OF THE UPPER TROUGH/DRY LINE AND ALL MODELS EXCEPT THE
NAM ARE IN VERY GOOD AGREEMENT. THEREFORE...CHANCE TO LIKELY POPS
ARE WARRANTED AT THIS TIME.
THE UPPER TROUGH AXIS IS PROGGED TO MOVE EAST OF THE REGION BY
WEDNESDAY MORNING WITH DRY NORTHWEST TO WEST FLOW EXPECTED THE
REMAINDER OF THE WEEK THROUGH THE WEEKEND. IT WILL BE COOLER AND
DRIER WEDNESDAY THROUGH SATURDAY WITH HIGHS MAINLY IN THE 50S AND
60S AND LOWS GENERALLY IN THE 30S AND 40S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 73 61 75 63 76 / 10 10 10 20 50
WACO, TX 72 63 76 63 76 / 10 10 10 20 50
PARIS, TX 68 61 75 60 76 / 10 10 10 20 60
DENTON, TX 72 61 75 61 75 / 10 10 10 20 50
MCKINNEY, TX 71 64 74 62 76 / 10 10 10 20 50
DALLAS, TX 73 64 76 63 76 / 10 10 10 20 50
TERRELL, TX 73 64 75 63 75 / 10 10 10 20 60
CORSICANA, TX 74 63 77 62 75 / 10 10 10 20 50
TEMPLE, TX 74 62 76 63 76 / 10 10 10 20 40
MINERAL WELLS, TX 74 57 76 60 72 / 10 10 10 20 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR TXZ091>095-
100>107-115>123-129>135-141>148-156-157-159-161.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
443 AM CST SUN JAN 27 2013
.VERY SHORT TERM...TODAY AND TONIGHT. FORECAST CONFIDENCE MEDIUM.
FOCUS SQUARELY ON PRECIPITATION TYPE/TIMING WITH POTENT SHORT WAVE
APPROACHING FROM THE SOUTHWEST. ENHANCED CLOUDS IN PACIFIC MOISTURE
PLUME AHEAD OF WAVE WRAPPING AROUND MULTIPLE VORTICITY MAXIMA NOTED
ON WATER VAPOR LOOPS OVER SW NEBRASKA...EASTERN KANSAS AND EXTREME
SE COLORADO...WITH A PRONOUNCED DRY SLOT BEHIND PLUME FROM NRN MEXICO
INTO KANSAS.
PRECIPITATION MOVES IN LATE THIS MORNING/EARLY AFTERNOON INTO
THIS EVENING WITH A BAND OF PRECIPITATION ASSOCIATED WITH STRONG
LAYER FRONTOGENETIC RESPONSE TO 850-700MB WARM AIR ADVECTION AHEAD
OF THE WAVE. MODEL SOUNDINGS SHOW INITIAL MOISTENING NEEDED TO
SATURATE DRY LAYER BELOW 750 MB...WITH EVAPORATIVE COOLING TAKING
THE WET BULB TEMP TO 0C IN THE COLUMN FOR A PERIOD OF ALL SNOW TO
START...THEN WARMING ALOFT AND LOSS OF ICE CRYSTALS WITH THE DGZ
DRYING OUT AS PRONOUNCED DRY SLOT PUSHING NEWD ACROSS KANSAS ON
WATER VAPOR LOOPS INTRODUCES LIQUID INTO THE SUB-0C LAYER BELOW 900
MB TO THE SURFACE. THIS BRINGS SLEET AND EVENTUALLY FREEZING RAIN
INTO THE MIX...GOING TO ALL LIGHT FREEZING RAIN AND THEN RAIN.
CONSENSUS QPF AMOUNTS AND TEMPERATURE TRENDS BRINGS ICE
ACCUMULATIONS BETWEEN 0.10 AND 0.20...WITH SNOW AROUND 0.5
SOUTH...WITH 1 TO 1.5 NORTH WITH LATER SWITCH TO A MIX. WHILE THIS
WILL BE A WINTRY MESS...AMOUNTS STAY WITHIN ADVISORY GUIDELINES.
WILL MONITOR DURING EVENT AS NAM SOUNDINGS WERE SHOWING A MORE
PROLONGED PERIOD OF SNOW...WHILE RAP LEANED MORE TOWARDS FZRA TO
RAIN WITH VERY LITTLE SNOW.
SURFACE TEMPS WARM ENOUGH FOR ALL RAIN BY 06Z MONDAY..EXCEPT FOR AN
AREA IN THE FAR NRN CWA SO WILL KEEP START AND END TIMES AS IS FOR
ADVISORY. WITH WARMING THROUGH THE DAY AND LITTLE DROP OFF
TONIGHT...WENT WITH LATE HIGHS IN THE LOW TO MID 30S..AND LOWS ONLY
A FEW DEGREES COOLER.
MONDAY - CONFIDENCE...MEDIUM
SHORTWAVE AXIS ACROSS THE CWA EARLY ON WITH THIS WAVE WHISKING EAST
PRETTY QUICK. BASED ON CONSENSUS OF MODELS WILL LIMIT POPS TO JUST
THE MORNING HOURS. BRIEF PERIOD OF SURFACE/850 RIDGING TAKING HOLD.
MONDAY NIGHT - CONFIDENCE...MEDIUM
STRENGTHENING 40-50 KNOT SW LOW LEVEL JET AIMS AT THE CWA. DECENT
MOISTURE ADVECTION NOTED. ECMWF HAS QPF MAX NEAR WI/IL BORDER WHILE
GEM HAS IT MORE ACROSS THE CWA. NOT IMPRESSED WITH BUFKIT ELEVATED
CAPE OR LAPSE RATES SO WILL HOLD OFF ON THUNDER MENTION FOR NOW. DID
NUDGE POPS UP A BIT MORE THOUGH.
TUESDAY - CONFIDENCE...MEDIUM
MODELS TAKE SURFACE LOW VICINITY OF NE IA/SW WI AND RACE IT
NORTHEAST THROUGH THE DAY. THIS WILL DRAG A COLD FRONT ACROSS SRN
WI...BUT BEFORE FRONT ARRIVES...PLENTY OF MILD AIR IN PLACE. 925
TEMPS IN THE 10-12C RANGE ON THE ECMWF/GFS...WHILE THE NAM IS MUCH
QUICKER TO BRING THE FRONT THROUGH. GOING WITH THE CONSENSUS OF THE
ECMWF/GFS WILL HAVE TEMPS INTO THE 50S FOR THE SE CWA. ADDED A
CHANCE OF THUNDER IN THE FAR SE DUE TO PREFRONTAL SOUNDINGS
REVEALING ELEVATED INSTABILITY. THERMODYNAMICS LOOKING BETTER TO OUR
SOUTH AND SOUTHEAST PER TRENDS IN CWASP. SWODY3 GENERAL DOES CLIP
OUR SE AS WELL.
WEDNESDAY - CONFIDENCE...MEDIUM
LOW LEVEL COLD ADVECTION WITH MID LEVEL TROUGH AXIS SWINGING ACROSS.
PRESSURE GRADIENT FAIRLY TIGHT AND WITH DECENT MIXING IN LOW LEVELS
EXPECT NW WINDS TO BE ON THE GUSTY SIDE. SO A STARK CONTRAST TO THE
MILD CONDITIONS OF TUESDAY. ECWMF A BIT SLOWER ON THE COLD
ADVECTION...SEEING A 5-7 DEGREE DIFFERENCE WITH 925 TEMPS. DRY SLOT
STILL IN PLACE THROUGH MIDDAY THEN A LITTLE MORE MOISTURE EXPECTED.
WILL GO WITH THE SLIGHT CHANCE OF SNOW SHOWERS AS DEPICTED BY
ALLBLEND POPS.
THURSDAY - CONFIDENCE...MEDIUM
COLDER YET WITH 925 TEMPS -20 TO -24C WHICH SUGGESTS SINGLE DIGIT
HIGH TEMPS FOR MUCH OF THE CWA. ALLBLEND SHOWING 10-15 BUT THAT MAY
BE TOO WARM. MIXED IN SOME COLDER NUMBERS FROM THE CONSRAW TO BRING
TEMPS DOWN A BIT CLOSER TO THE 925 SCHEME.
FRIDAY - CONFIDENCE...MEDIUM
ECMWF/GFS AGREE THAT CORE OF COLDEST AIR SHIFTS EAST WITH LOW LEVEL
WARM ADVECTION GETTING UNDERWAY AHEAD OF THE NEXT TROUGH.
FRIDAY NIGHT AND SATURDAY - CONFIDENCE...MEDIUM
COMBO OF WARM ADVECTION AND PASSAGE OF SURFACE/850 TROUGH BRINGS
SHSN CHANCES THIS PERIOD. NOT LOOKING LIKE MUCH AT THIS POINT. ECMWF
MUCH MORE AGGRESSIVE ON DEGREE OF COLD ADVECTION IN THE WAKE OF THE
FRONT SATURDAY AFTERNOON/EVENING.
&&
.AVIATION/12Z TAFS/...VFR CONDITIONS WILL DETERIORATE QUICKLY TO
MVFR WITH PCPN MOVING INTO KMSN AROUND 17Z-18Z...KUES 18Z-19Z AND
KMKE AND KENW AROUND 20Z...THEN FALLING TO IFR AND HOLDING THROUGH
THE REMAINDER OF THE FORECAST. PCPN SHOULD START OUT AS LIGHT
SNOW...MIXING WITH SLEET AND THEN FREEZING RAIN...GOING OVER TO ALL
RAIN AS TEMPERATURES WARM. PERIOD OF FREEZING RAIN WILL BE SHORTER
AT KMKE AND KENW AS TEMPERATURES WILL RISE ABOVE FREEZING SOONER
WITH SE WINDS.
&&
.MARINE...
EXTENDED SMALL CRAFT ADVISORY UNTIL 12Z MONDAY TO ALLOW WAVES
SUFFICIENT TIME TO SUBSIDE AFTER WINDS FALL OFF BELOW CRITERIA LATE
THIS EVENING. WINTRY MIX OVERSPREADING THE NEARSHORE THIS AFTERNOON
WILL GO OVER TO RAIN
WINDS WILL HOVER AROUND SMALL CRAFT CRITERIA FROM TUESDAY NIGHT
THROUGH FRIDAY AS THE GRADIENT TIGHTENS BETWEEN ANOTHER LOW PRESSURE
AREA CROSSING THE WESTERN GREAT LAKES REGION TUESDAY AND ARCTIC HIGH
PRESSURE BUILDING INTO THE NORTHERN PLAINS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR WIZ062-063-067>069.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT
CST TONIGHT FOR WIZ059-060-064>066-070>072.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 3 AM CST MONDAY FOR
WIZ046-047-056-057.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 3 AM CST
MONDAY FOR WIZ051-052-058.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 AM CST MONDAY FOR
LMZ643>646.
&&
$$
UPDATED TO ADD MARINE SECTION.
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...COLLAR
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
351 AM CST SUN JAN 27 2013
.VERY SHORT TERM...TODAY AND TONIGHT. FORECAST CONFIDENCE
FOCUS SQUARELY ON PRECIPITATION TYPE/TIMING WITH POTENT SHORT WAVE
APPROACHING FROM THE SOUTHWEST. ENHANCED CLOUDS IN PACIFIC MOISTURE
PLUME AHEAD OF WAVE WRAPPING AROUND MULTIPLE VORTICITY MAXIMA NOTED
ON WATER VAPOR LOOPS OVER SW NEBRASKA...EASTERN KANSAS AND EXTREME
SE COLORADO...WITH A PRONOUNCED DRY SLOT BEHIND PLUME FROM NRN MEXICO
INTO KANSAS.
PRECIPITATION MOVES IN LATE THIS MORNING/EARLY AFTERNOON INTO
THIS EVENING WITH A BAND OF PRECIPITATION ASSOCIATED WITH STRONG
LAYER FRONTOGENETIC RESPONSE TO 850-700MB WARM AIR ADVECTION AHEAD
OF THE WAVE. MODEL SOUNDINGS SHOW INITIAL MOISTENING NEEDED TO
SATURATE DRY LAYER BELOW 750 MB...WITH EVAPORATIVE COOLING TAKING
THE WET BULB TEMP TO 0C IN THE COLUMN FOR A PERIOD OF ALL SNOW TO
START...THEN WARMING ALOFT AND LOSS OF ICE CRYSTALS WITH THE DGZ
DRYING OUT AS PRONOUNCED DRY SLOT PUSHING NEWD ACROSS KANSAS ON
WATER VAPOR LOOPS INTRODUCES LIQUID INTO THE SUB-0C LAYER BELOW 900
MB TO THE SURFACE. THIS BRINGS SLEET AND EVENTUALLY FREEZING RAIN
INTO THE MIX...GOING TO ALL LIGHT FREEZING RAIN AND THEN RAIN.
CONSENSUS QPF AMOUNTS AND TEMPERATURE TRENDS BRINGS ICE
ACCUMULATIONS BETWEEN 0.10 AND 0.20...WITH SNOW AROUND 0.5
SOUTH...WITH 1 TO 1.5 NORTH WITH LATER SWITCH TO A MIX. WHILE THIS
WILL BE A WINTRY MESS...AMOUNTS STAY WITHIN ADVISORY GUIDELINES.
WILL MONITOR DURING EVENT AS NAM SOUNDINGS WERE SHOWING A MORE
PROLONGED PERIOD OF SNOW...WHILE RAP LEANED MORE TOWARDS FZRA TO
RAIN WITH VERY LITTLE SNOW.
SURFACE TEMPS WARM ENOUGH FOR ALL RAIN BY 06Z MONDAY..EXCEPT FOR AN
AREA IN THE FAR NRN CWA SO WILL KEEP START AND END TIMES AS IS FOR
ADVISORY. WITH WARMING THROUGH THE DAY AND LITTLE DROP OFF
TONIGHT...WENT WITH LATE HIGHS IN THE LOW TO MID 30S..AND LOWS ONLY
A FEW DEGREES COOLER.
MONDAY - CONFIDENCE...MEDIUM
SHORTWAVE AXIS ACROSS THE CWA EARLY ON WITH THIS WAVE WHISKING EAST
PRETTY QUICK. BASED ON CONSENSUS OF MODELS WILL LIMIT POPS TO JUST
THE MORNING HOURS. BRIEF PERIOD OF SURFACE/850 RIDGING TAKING HOLD.
MONDAY NIGHT - CONFIDENCE...MEDIUM
STRENGTHENING 40-50 KNOT SW LOW LEVEL JET AIMS AT THE CWA. DECENT
MOISTURE ADVECTION NOTED. ECMWF HAS QPF MAX NEAR WI/IL BORDER WHILE
GEM HAS IT MORE ACROSS THE CWA. NOT IMPRESSED WITH BUFKIT ELEVATED
CAPE OR LAPSE RATES SO WILL HOLD OFF ON THUNDER MENTION FOR NOW. DID
NUDGE POPS UP A BIT MORE THOUGH.
TUESDAY - CONFIDENCE...MEDIUM
MODELS TAKE SURFACE LOW VICINITY OF NE IA/SW WI AND RACE IT
NORTHEAST THROUGH THE DAY. THIS WILL DRAG A COLD FRONT ACROSS SRN
WI...BUT BEFORE FRONT ARRIVES...PLENTY OF MILD AIR IN PLACE. 925
TEMPS IN THE 10-12C RANGE ON THE ECMWF/GFS...WHILE THE NAM IS MUCH
QUICKER TO BRING THE FRONT THROUGH. GOING WITH THE CONSENSUS OF THE
ECMWF/GFS WILL HAVE TEMPS INTO THE 50S FOR THE SE CWA. ADDED A
CHANCE OF THUNDER IN THE FAR SE DUE TO PREFRONTAL SOUNDINGS
REVEALING ELEVATED INSTABILITY. THERMODYNAMICS LOOKING BETTER TO OUR
SOUTH AND SOUTHEAST PER TRENDS IN CWASP. SWODY3 GENERAL DOES CLIP OUR
SE AS WELL.
WEDNESDAY - CONFIDENCE...MEDIUM
LOW LEVEL COLD ADVECTION WITH MID LEVEL TROUGH AXIS SWINGING ACROSS.
PRESSURE GRADIENT FAIRLY TIGHT AND WITH DECENT MIXING IN LOW LEVELS
EXPECT NW WINDS TO BE ON THE GUSTY SIDE. SO A STARK CONTRAST TO THE
MILD CONDITIONS OF TUESDAY. ECWMF A BIT SLOWER ON THE COLD
ADVECTION...SEEING A 5-7 DEGREE DIFFERENCE WITH 925 TEMPS. DRY SLOT
STILL IN PLACE THROUGH MIDDAY THEN A LITTLE MORE MOISTURE EXPECTED.
WILL GO WITH THE SLIGHT CHANCE OF SNOW SHOWERS AS DEPICTED BY
ALLBLEND POPS.
THURSDAY - CONFIDENCE...MEDIUM
COLDER YET WITH 925 TEMPS -20 TO -24C WHICH SUGGESTS SINGLE DIGIT
HIGH TEMPS FOR MUCH OF THE CWA. ALLBLEND SHOWING 10-15 BUT THAT MAY
BE TOO WARM. MIXED IN SOME COLDER NUMBERS FROM THE CONSRAW TO BRING
TEMPS DOWN A BIT CLOSER TO THE 925 SCHEME.
FRIDAY - CONFIDENCE...MEDIUM
ECMWF/GFS AGREE THAT CORE OF COLDEST AIR SHIFTS EAST WITH LOW LEVEL
WARM ADVECTION GETTING UNDERWAY AHEAD OF THE NEXT TROUGH.
FRIDAY NIGHT AND SATURDAY - CONFIDENCE...MEDIUM
COMBO OF WARM ADVECTION AND PASSAGE OF SURFACE/850 TROUGH BRINGS
SHSN CHANCES THIS PERIOD. NOT LOOKING LIKE MUCH AT THIS POINT. ECMWF
MUCH MORE AGGRESSIVE ON DEGREE OF COLD ADVECTION IN THE WAKE OF THE
FRONT SATURDAY AFTERNOON/EVENING.
&&
.AVIATION/12Z TAFS/...VFR CONDITIONS WILL DETERIORATE QUICKLY TO MVFR
WITH PCPN MOVING INTO KMSN AROUND 17Z-18Z...KUES 18Z-19Z AND KMKE
AND KENW AROUND 20Z...THEN FALLING TO IFR AND HOLDING THROUGH THE
REMAINDER OF THE FORECAST. PCPN SHOULD START OUT AS LIGHT
SNOW...MIXING WITH SLEET AND THEN FREEZING RAIN...GOING OVER TO
ALL RAIN AS TEMPERATURES WARM. PERIOD OF FREEZING RAIN WILL BE
SHORTER AT KMKE AND KENW AS TEMPERATURES WILL RISE ABOVE FREEZING
SOONER WITH SE WINDS.
&&
.MARINE...COMING SOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR WIZ062-063-067>069.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR WIZ059-060-064>066-070>072.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 3 AM CST MONDAY FOR
WIZ046-047-056-057.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 3 AM CST
MONDAY FOR WIZ051-052-058.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 AM CST MONDAY FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...COLLAR
AREA FORECAST DISCUSSION...CORRECTED
NWS LA CROSSE WI
344 AM CST SUN JAN 27 2013
CORRECTED INITIALS AT BOTTOM OF PRODUCT
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
344 AM CST SUN JAN 27 2013
MAIN FORECAST CONCERNS ARE ON 2 MIXED PRECIPITATION EVENTS...
TODAY/TONIGHT AND MONDAY NIGHT/TUESDAY.
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED TROUGHING ACROSS THE PACIFIC NORTHWEST INTO THE SAN FRANSISCO
AREA...A FAIRLY POTENT SHORTWAVE OVER EASTERN COLORADO...AND RIDGING
BUILDING DOWNSTREAM OF THIS SHORTWAVE FROM ARKANSAS NORTH INTO
MINNESOTA. TROPOPAUSE ANALYSIS SHOWED A 100-120KT JET NEAR 250MB
ACROSS MUCH OF THE WESTERN GREAT LAKES...PLACING MUCH OF IOWA IN THE
FAVORABLE UPPER DIVERGENCE LEFT ENTRANCE REGION. THIS FORCING...
COMBINED WITH AN UPPER LEVEL MOISTURE PLUME OUT OF THE EASTERN
PACIFIC AHEAD OF THE COLORADO SHORTWAVE AS SEEN ON WATER VAPOR...
RESULTING IN WIDESPREAD MID/HIGH CLOUDS OVER THE FORECAST AREA.
THESE CLOUDS COMBINED WITH A SOUTHERLY BREEZE HAS ALLOWED
TEMPERATURES TO HOLD STEADY OR CLIMB SLOWLY OVERNIGHT. DEWPOINTS ARE
STILL QUITE DRY...THOUGH...IN THE LOW TEENS. THIS LOW LEVEL DRY AIR
SHOWS UP ON 00Z SOUNDINGS FROM DVN...MPX AND GRB. TO THE
SOUTHWEST...RADAR SHOWED AN AREA OF PRECIPITATION FROM WESTERN
NEBRASKA INTO NORTHWEST MO. A COUPLE OF FEATURES ARE AT WORK
PRODUCING THE PRECIPITATION. FIRST IS THE DPVA DOWNSTREAM OF THE
COLORADO SHORTWAVE. SECOND IS A LOW LEVEL JET TRANSPORTING GULF OF
MEXICO MOISTURE NORTHWARD THROUGH THE SOUTHERN AND CENTRAL PLAINS.
850MB VWP AND PROFILER DATA SHOWED 30-50 KT SOUTHWEST WINDS FROM
TEXAS INTO KS...AND EVEN ALL THE WAY UP INTO OUR FORECAST AREA. GOES
PRECIPITABLE WATER IMAGERY SHOWED VALUES AROUND 1 INCH IN ST JOSEPH
MO. THIS LOW LEVEL JET WAS ALSO TRANSPORTING WARM AIR NORTHWARD...
NOTED BY A RAP SOUNDING AT KLSE SHOWING AN 850MB AND 900MB TEMP
AROUND 4C. THIRD WAS LOW TO MID LEVEL FRONTOGENESIS OCCURRING ALONG
A SURFACE WARM FRONT NEAR I-70 IN KS. LASTLY...WATER VAPOR SHOWED A
NOTICEABLE DRY SLOT ACCOMPANYING THE SHORTWAVE...FROM NEW MEXICO
INTO CENTRAL KANSAS.
MODEL PREFERENCES/TRENDS
FOCUS IS ALL ON THE POTENT SHORTWAVE IN EASTERN COLORADO.
STRENGTH...MODELS CONTINUE TO VARY...WITH THE 27.00Z GFS AND
CANADIAN LOOKING THE MOST POTENT...THE 26.12Z ECMWF THE WEAKEST AND
THE 27.00Z UKMET/NAM IN-BETWEEN. GIVEN THE APPEARANCE OF THE
SHORTWAVE ON WATER VAPOR...HAVE LEANED MORE TOWARDS THE GFS/CANADIAN
SOLUTION. IN ADDITION...THERE HAS BEEN A TREND OVER THE PAST FEW
DAYS FROM ALL MODELS TO BE STRONGER. THE STRENGTH IS CRITICAL AS A
STRONGER WAVE ALLOWS WARMER AIR TO GET PULLED NORTH VERSUS THE
WEAKER WAVE SOLUTIONS.
TRACK...ANOTHER TREND IS FOR THE SHORTWAVE TO TRACK FARTHER
NORTH...NOW LOOKING TO GO THROUGH CENTRAL MN AT 00Z MON VERSUS
THROUGH THE FORECAST AREA SEEN YESTERDAY. THIS ALSO HAS A HUGE
IMPACT...SINCE IT SENDS THE DPVA FORCED PRECIPITATION FARTHER NORTH.
IN ADDITION...GIVEN THAT WE HAVE A STRONGER WAVE...THE DRY-SLOT
POTENTIAL TO IMPACT PRECIPITATION IS GREATER FOR OUR FORECAST AREA.
DETAILS OF THE FORECAST
TODAY AND TONIGHT...
NO MATTER WHAT SOLUTION IS FOLLOWED...285-300K ISENTROPIC LIFT PROGS
SUGGEST THE FORECAST AREA WILL SEE PRECIPITATION...ESPECIALLY IN THE
18Z TODAY - 06Z TONIGHT WINDOW AS HAS BEEN PREVIOUSLY FORECAST. THUS
100 PERCENT CHANCES ARE IN ORDER. PRECIPITATION CURRENTLY IN KANSAS
SHOULD SPREAD SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA IN THE
15-21Z WINDOW. PRECIPITATION THEN DIMINISHES AFTER 06Z WEST TO EAST
AS THE SHORTWAVE LIFTS INTO LAKE SUPERIOR...YIELDING SUBSIDENCE FROM
BOTH DPVA AND ISENTROPIC DESCENT. GIVEN THE PREFERENCE FOR THE
STRONGER SHORTWAVE SOLUTION...SOME CHANGES ARE NEEDED TO THE
FORECAST:
1. THERE ARE STRONG INDICATIONS THAT THE CURRENT PRECIPITATION
AREA...AS IT LIFTS NORTHEAST...IS GOING TO SPLIT INTO TWO DUE TO THE
DRY-SLOT. ONE HEAVIER QPF AREA WILL HEAD THROUGH SOUTHEAST MN INTO
NORTHERN WISCONSIN...ASSOCIATED WITH DPVA/FRONTOGENESIS ACCOMPANYING
THE SHORTWAVE. THE OTHER HEAVIER QPF AREA HEADS EAST TOWARDS
CHICAGO...SUPPORTED BY THE BETTER 850MB MOISTURE TRANSPORT. HAVE
ADJUSTED THE QPF FORECAST TO SHOW THIS SPLIT. NOTE THAT THERE ARE
INDICATIONS OF A THIRD QPF AREA AFTER 06Z...IMPACTING SOUTHERN
PORTIONS OF THE AREA. THIS IS TIED TO LOW LEVEL FRONTOGENESIS WITH A
SURFACE LOW AND WARM FRONT.
2. PRECIPITATION TYPE...EXTREMELY SENSITIVE! INITIAL WARM AIR WILL
RESULT IN FREEZING RAIN/SLEET. THEN...UNDER THE HEAVIER QPF AREA
HEADING NORTH...DYNAMIC AND EVAPORATIVE COOLING SHOULD KEEP THE BULK
OF IT AS SNOW OR PERHAPS A LITTLE SLEET MIXED IN. JUST USING 850MB
TEMPS AS A PROXY...PROGS FROM THE GFS/CANADIAN DEPICT THE DYNAMIC
COOLING IMPACT WELL. SOUTH OF THE NORTHERN HEAVIER QPF AREA...WARM
AIR SHOULD GET PULLED NORTH...ALLOWING MORE FOR A SLEET AND FREEZING
RAIN SITUATION SOUTH OF I-90. EVENTUALLY THIS IS ALL GOING TO
TRANSITION TO A RAIN/DRIZZLE IN THE EVENING HOURS DUE TO THE DRY
SLOT SCOURING OUT THE ICE...WITH LIFT STILL OCCURRING BELOW. THE
QUESTION IS IF THIS RAIN/DRIZZLE IS GOING TO BE FREEZING...SINCE
WARMER SURFACE AIR SHOULD ALSO ADVECT NORTH AS THE SURFACE WARM
FRONT APPROACHES. ALLOWED PRECIPITATION TO CHANGE OVER TO RAIN IN
THE FAR SOUTH...PER GFS/REGIONAL CANADIAN PROGS. GIVEN THE COLD ROAD
TEMPERATURES...THE RAIN/DRIZZLE MAY STILL FREEZE ON THE THEM.
IN SUMMARY...THE WARNINGS MAY BE DIFFICULT TO VERIFY. THE NORTHERN
HEAVIER QPF AREA MAY ONLY RESULT IN 3-5 INCHES OF SNOW AT ANY ONE
LOCATION. MEANWHILE...THE AMOUNT OF FREEZING RAIN/DRIZZLE IS PERHAPS
1/10 TO AT MOST 2/10 INCH. SLEET ACCUMULATIONS ARE MOST LIKELY ON
THE SOUTHERN EDGE OF THE NORTHERN HEAVIER QPF AREA...AND MAY ONLY
END UP BEING A FEW TENTHS. HOWEVER...GIVEN THAT THIS IS A MESSY
SITUATION AND WARNINGS ARE ALREADY POSTED...ALONG WITH THE EXTREME
SENSITIVE NATURE TO THE WARM LAYER ALOFT...WILL GIVE THEM A CHANCE
AND LET THEM RIDE.
LASTLY...AS THE PRECIPITATION COMES TO AN END LATER TONIGHT...
SUBSIDENCE WILL TRAP IN A LOT OF LOW LEVEL MOISTURE. SURFACE WINDS
ARE LIGHT...YIELDING A FAVORABLE SCENARIO FOR FOG DEVELOPMENT. HAVE
MAINTAINED AREAS OF FOG. IF THERE IS ANY DENSE FOG DEVELOPMENT...IT
WOULD HAPPEN ACROSS THE HIGHER TERRAIN ALONG/SOUTH OF I-90. LATER
SHIFTS MAY NEED TO ISSUE DENSE FOG ADVISORIES.
MONDAY THROUGH TUESDAY NIGHT...
ATTENTION RE-FOCUSES TO THE WEST WITH THE WEST COAST U.S. TROUGH.
MODELS REMAIN IN GOOD AGREEMENT DIGGING A DEEP TROUGH WHICH
PROGRESSES EASTWARD DURING THIS PERIOD. BY 12Z WEDNESDAY...THE AXIS
EXTENDS FROM MINNESOTA INTO TEXAS. AS THIS TROUGH MOVES INTO THE
AREA TUESDAY NIGHT...925/850MB TEMPS BEGIN TO PLUMMET...WITH BOTH
FALLING TO -8 TO -14C BY 12Z WEDNESDAY. FURTHER COOLING TAKES PLACE
HEADING INTO THE LONG TERM PERIOD BELOW. PRIOR TO THIS COLD
ADVECTION...27.00Z ECMWF/GFS/CANADIAN/UKMET SHOW A SHORTWAVE
EJECTING OUT OF THE TROUGH MONDAY AFTERNOON THROUGH MONDAY NIGHT
ACROSS THE CENTRAL PLAINS. 27.00Z NAM WAS A MAJOR OUTLIER HANDLING
THIS SHORTWAVE AND WILL NOT MENTION. THIS SHORTWAVE LEADS TO A
SURFACE LOW WHICH DEEPENS AND REACHES EASTERN IOWA BY 12Z TUESDAY.
EXPECTING A DRY MONDAY...BUT CLOUDY WITH MORNING FOG...DUE TO
SUBSIDENCE AGAIN TRAPPING IN LOW LEVEL MOISTURE. AGAIN...MAY HAVE
SOME DENSE FOG. SHOULD BE A WARM DAY COMPARED TO WHAT WE HAVE SEEN
LATELY. AS THE LOW APPROACHES MONDAY NIGHT...LOW LEVEL LIFT AND
ISENTROPIC LIFT INCREASES...RESULTING IN LIGHT PRECIPITATION. THERE
IS A WARM LAYER ALOFT...BETWEEN 4-7C...BUT SURFACE TEMPERATURES IN
THE EVENING COULD COOL DOWN BELOW FREEZING. NO ICE IS PRESENT
EITHER. THIS SETS UP A POSSIBLE FREEZING RAIN SITUATION.
HOWEVER...IT LOOKS TO BE BRIEF BECAUSE AS THE LOW APPROACHES...
SURFACE TEMPERATURES WARM ABOVE FREEZING. IN FACT...BY 12Z...THE
27.00Z ECMWF HAS PLATTEVILLE AS WARM AS 53F. HAVE NOT GONE THAT
WARM...BUT DID WARM THAT AREA UP FOR A HIGH ON TUESDAY IN THE UPPER
40S. SOME LINGERING LIGHT PRECIPITATION CONTINUES INTO TUESDAY
MORNING...THEN THE DRY SLOT WITH THE SHORTWAVE PASSAGE SHOULD CLEAR
THE PRECIP OUT. THUS...CHANCES OF PRECIPITATION ARE HIGHEST IN THE
06-18Z TUESDAY WINDOW. BEST CHANCES OF FREEZING RAIN TOO ARE IN THE
NORTHWEST THIRD OF THE FORECAST AREA. ALSO TO NOTE...ADDED AREAS
OF FOG ACROSS THE FORECAST AREA MONDAY NIGHT INTO TUESDAY
MORNING...DUE TO LOW LEVEL MOISTURE STILL TRAPPED AND LIGHT WINDS.
THIS TOO COULD BE A TIME PERIOD REQUIRING DENSE FOG ADVISORIES.
HEADING INTO TUESDAY NIGHT... A SECONDARY COLD FRONT ASSOCIATED
WITH THE LOW LOOKS TO CROSS THE AREA. KEPT A SMALL CHANCE OF SNOW
SHOWERS WITH THIS FRONT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
344 AM CST SUN JAN 27 2013
27.00Z ECMWF/GFS/CANADIAN/UKMET AND ECMWF ENSEMBLES ARE IN REALLY
GOOD AGREEMENT THROUGH THE LONG TERM PERIOD. THE UPPER TROUGHING
THAT WAS APPROACHING THE AREA AT 12Z WEDNESDAY SHIFTS ACROSS DURING
THE DAY. MAINTAINED 20 PERCENT CHANCES OF PRECIPITATION ACROSS
WISCONSIN AS THAT SECONDARY COLD FRONT ASSOCIATED WITH THE UPPER
TROUGH MOVES THROUGH. UPSTREAM...A POTENT SHORTWAVE TROUGH CURRENTLY
NEAR ANCHORAGE ALASKA IS FORECAST TO DIG DOWN AND RE-ENFORCE THE
TROUGH. THIS FEATURES DROPS INTO THE AREA ON THURSDAY...BRINGING
WITH IT A SURGE OF ARCTIC AIR. 850MB TEMPS TUMBLE TO -22 TO -26C BY
00Z FRIDAY...AFTER BEING AT -15 TO -20C AT 00Z THURSDAY. GIVEN THE
NORTHWEST FLOW AND ARCTIC ORIGIN...NO PRECIPITATION IS MENTIONED
WITH THIS POTENT SHORTWAVE TROUGH. NEEDLESS TO SAY...TEMPERATURES
WILL BE BELOW NORMAL WITH WIND CHILL ADVISORIES LOOKING LIKELY
THURSDAY NIGHT AND EVEN FOR A FEW AREAS WEDNESDAY NIGHT. THE
NORTHWEST UPPER LEVEL FLOW IS PROGGED TO STAY AROUND THROUGH FRIDAY
AND SATURDAY...WITH SOME INDICATIONS OF YET ANOTHER POTENT SHORTWAVE
TROUGH DROPPING THROUGH ON SATURDAY. 500MB HEIGHTS DO RISE SOME
FRIDAY AND SATURDAY...SO THIS LATTER TROUGH ENDS UP A LITTLE FARTHER
NORTH. DID KEEP SOME 20-30 PERCENT CHANCES AS THE TROUGH MOVES
THROUGH. WITH THE INCREASING 500MB HEIGHTS...TEMPERATURES SHOULD
MODERATE SOME.
&&
.AVIATION...
1030 PM CST SAT JAN 26 2013
IMPACTFUL WEATHER SYSTEM WILL BRING A MIXED BAG OF WINTERY PCPN TO
THE REGION AS WARMER AIR A LOFT...AND THEN THE POTENTIAL FOR LOSS OF
ICE IN THE CLOUD AS IT PASSES...MAKE -SN/IP/FZRA/FZDZ ALL POSSIBLE.
HOW FAR NORTH THE SYSTEM MOVES WILL HAVE A BIG IMPACT ON THE PTYPE
FOR KRST/KLSE...WITH CURRENT THINKING MAKING -SN/IP MORE LIKELY FOR
LATE MORNING/AFTERNOON SUNDAY. IP/FZRA/FZDZ START TO LOOK MORE
LIKELY FOR THE EVENING HOURS AS THE WARM LOW LEVEL AIR CREEPS
FARTHER NORTH. HOWEVER...MODELS DEPICT...AND SATELLITE IMAGERY
SHOWS...THAT THERE IS A PRETTY STRONG DRY PUNCH IN THE MID LEVELS
WITH THIS SYSTEM...AND ITS SLATED TO MOVE ACROSS THE TAF SITE SUNDAY
EVENING. THIS WOULD CARVE OUT THE ICE BEARING PART OF THE
CLOUD...AND THUS LEAVE FZDZ AS THE PTYPE. DIFFICULT PCPN TYPE
FORECAST. VERY DIFFICULT. SOME SNOW AND ICE ACCUMULATION ARE LIKELY.
EXPECT A RAPID DROP IN CIGS...WITH MID LEVEL CLOUDS AND VFR
CONDITIONS INTO MID MORNING SUNDAY...DROPPING TO AROUND 1KFT OR LESS
BY 18Z. VSBYS FROM 2 TO 4SM LOOK LIKELY AT THIS TIME...BUT WILL BE
LOWER WHEN -SN IS THE PROMINENT PTYPE. WILL HANG ONTO SUB 2SM INTO
THE EVENING...WITH BR AND FZDZ MORE OF A FACTOR. THE LIFR/IFR CIGS
WILL PERSIST THROUGH SUNDAY NIGHT. MOST OF THE ACCUMULATING PCPN
LOOKS TO EXIT EAST AFTER 06Z MON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
344 AM CST SUN JAN 27 2013
WI...WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ029-032>034-041>044-053>055-061.
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ017.
MN...WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR MNZ079-086>088-094>096.
IA...WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 PM MST MON JAN 28 2013
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER WESTERN ARIZONA MONDAY
EVENING WILL PUSH EAST ACROSS THE AREA TONIGHT INTO TUESDAY MORNING.
EXPECT SCATTERED SHOWERS WITH SNOW LEVELS LOWERING DOWN TO AROUND
3500 FEET. MINOR SNOW ACCUMULATIONS ARE POSSIBLE SOUTH AND EAST OF
TUCSON. COLD TUESDAY AND WEDNESDAY MORNING. EXPECT DRY CONDITIONS TO
RETURN THE SECOND HALF OF THE WEEK ALONG WITH WARMER TEMPERATURES.
&&
.DISCUSSION...WATER VAPOR IMAGERY SHOWED UPPER LEVEL TROF AXIS
EXTENDING FROM THE FOUR CORNERS SW TO JUST WEST OF ROCKY POINT. HAVE
HAD SCATTERED LIGHT SHOWERS GOING MOST OF THIS EVENING EAST OF
TUCSON WITH ANOTHER BATCH OF SHOWERS WEST SOUTHWEST OF TUCSON. 00Z
NAM AND RAP MODELS MOVE UPPER LEVEL TROF EAST OVERNIGHT WITH SHOWERS
INCREASING IN AREAL COVERAGE AS TROF ENCOUNTERED A LITTLE MORE
PRECIPITABLE WATER. THE SHOWERS THAT WERE OUT BY YUMA AND ROCKY
POINT EARLIER THIS EVENING HAS FALLEN APART AS THEY HAVE MOVED INTO
SOME DRIER AIR THAT RESIDES OVER CENTRAL PIMA COUNTY WHERE PW VALUES
WERE AROUND 0.35" BASED ON GPS. PW VALUES FROM TUCSON EAST ARE NEAR
A HALF AN INCH. SNOW LEVEL WILL LOWER TO AROUND 3500 FEET OVERNIGHT
WITH UP TO AN INCH ACROSS SANTA CRUZ AND COCHISE COUNTIES.
CONTEMPLATED WINTER WEATHER ADVISORY FOR THOSE COUNTIES BUT HELD OFF
ON ISSUING ONE. IF RADAR LIGHTS UP IN THE NEXT COUPLE OF HOURS THEN
WE MAY HAVE TO HOIST A QUICK ONE. OTHERWISE SENDING OUT ANOTHER
UPDATE TO THE FORECAST.
SYSTEM OUT OF HERE ON TUESDAY WITH STRONG NW FLOW ON BACK SIDE. MAY
SEE PRETTY STRONG WINDS IN NW-SE ORIENTED VALLEYS TUESDAY AFTERNOON.
SPEEDS MAY END UP NEAR ADVISORY CRITERIA.
&&
.AVIATION...BKN-OVC CLOUDS 5-8K FT AGL AND MTNS OBSCD...WITH SCT
-SHRA/SHSN THRU TONIGHT...THEN SKIES GRADUALLY CLEARING TUESDAY
MORNING. WINDS GENERALLY WLY-SWLY 12-22 KTS WITH HIGHER GUSTS EAST
OF TUCSON THROUGH 06Z TUESDAY...THEN MAINLY LESS THAN 10 KTS THROUGH
TUESDAY MORNING FROM KTUS WESTWARD AND 10-20 KTS ACROSS EASTERN
AREAS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...NO FIRE WEATHER CONCERNS. SCATTERED SHOWERS AND
BREEZY CONDITIONS INTO THIS EVENING. DRY WEATHER TUESDAY BUT WINDY
ESPECIALLY IN THE UPPER GILA RIVER VALLEY. TEMPERATURES WILL BEGIN
TO MODERATE WEDNESDAY WITH DRY CONDITIONS CONTINUING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY TIL 11 PM TONIGHT FOR AZZ510
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CST MON JAN 28 2013
.AVIATION...
WARM FRONT LIFTING NORTH THROUGH IOWA/ILLINOIS WILL RESULT IN
VLIFR CONDITIONS IMPROVING TO VFR. PRIOR TO AND FOR AN HOUR OR TWO
BEHIND THE FRONTAL PASSAGE LLWS IS LIKELY. RAP MODEL TRENDS
SUGGEST NEW CONVECTION WILL DVLP THROUGH 12Z/29 WITH SOME TSRA
POSSIBLE. COLD FRONT TO MOVE THROUGH EASTERN IOWA/ILLINOIS FROM
15Z/29 TO 00Z/30 BRINGING ANOTHER THREAT OF TSRA. VFR CONDITIONS
WILL DETERIORATE TO MVFR FOLLOWING THE PASSAGE OF THE COLD FRONT.
AFT 06Z/30 CONDITIONS WILL DETERIORATE TO IFR/LIFR WITH SN. ..08..
&&
.PREV DISCUSSION... /ISSUED 924 PM CST MON JAN 28 2013/
UPDATE...
UPDATED THE NPW JUST BEFORE 9 PM TO DROP THE CLARK AND SCOTLAND
COUNTIES. REPORTS FROM THAT AREA SUGGESTED VISIBILITIES WERE
IMPROVING ALTHOUGH SOME PATCHY FOG WAS STILL OCCURRING. THE REST
OF THE ADVISORY FOR THE SOUTHERN COUNTIES WAS EXTENDED TO 3 AM.
HOWEVER...RECENT OBS FROM KBRL SHOW VSBYS THERE UP TO 3SM. IF THIS
TREND CONTINUES PART OF THE ADVISORY WILL LIKELY BE DROPPED BEFORE
MIDNIGHT.
THUNDERSTORMS CONTINUE TO ERUPT OVER THE CENTRAL AND NORTHERN
CWFA. RADAR DATA SUGGESTS THAT SOME OF THE STORMS CONTAIN SMALL
HAIL BUT HAVE YET TO RECEIVE ANY REPORTS.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 3 AM CST TUESDAY FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-
KEOKUK-LINN-LOUISA-MUSCATINE-SCOTT-WASHINGTON.
IL...DENSE FOG ADVISORY UNTIL 3 AM CST TUESDAY FOR BUREAU-CARROLL-
HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
WHITESIDE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1139 PM CST MON JAN 28 2013
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION.../ISSUED AT 413 PM CST MON JAN 28 2013/
FIRST THE HEADLINES. STARTING WITH THE HRRR/RUC THEN THE REST OF
THE 12Z RUNS...MODELS BEGAN TO SHIFT HEAVY SNOW BAND FOR TONIGHT
FARTHER NORTHWEST...KEEPING THE BULK OF THE SNOW NW OF THE MPX
CWA. MAY STILL GET A COUPLE INCHES OF SNOW IN THE FAR NW CORNERS
OF TODD...DOUGLAS...AND STEVENS COUNTIES...SO WITH THAT ALONG WITH
MATCHING UP WITH WHAT NEIGHBORS WERE DOING...ISSUED A WINTER
WEATHER ADVISORY FOR THOSE THREE COUNTIES. AT THE OTHER END OF THE
CWA HAVE A FREEZING RAIN ADVISORY FOR NE 3 COUNTIES IN WI. NOT
THRILLED WITH DOING THIS ADVISORY...BUT TO MATCH UP WITH
NEIGHBORING OFFICES...INCLUDED THESE COUNTIES IN A FREEZING RAIN
ADVY. EVERYWHERE ELSE...DENSE FOG IS LOOKING LIKE ALL BUT A
CERTAINTY FOR TONIGHT...SO A NEW DENSE FOG ADVISORY HAS BEEN
HOISTED.
UPPER WAVE RESPONSIBLE FOR ALL OF THIS HEADLINE FUN IS A DEEP
THROUGH THAT CAN BE SEEN ACROSS THE ERN ROCKIES THIS
AFTERNOON...AND WILL SLIDE ACROSS THE CENTER OF THE CONUS THROUGH
WEDNESDAY. AT THIS SFC...A 996 MB LOW AT 3 PM WAS CENTERED OVER
ERN CO. FAIRLY GOOD CONSENSUS AMONGST GUIDANCE ON THIS LOW MOVING
TO NEAR THE SE TIP OF MN BY TUESDAY MORNING...THEN OFF TO ERN LAKE
SUPERIOR BY THE TUE AFTERNOON. SEEING AN IMPRESSIVE WARM FRONT
MOVING NORTH ACROSS THE PLAINS WITH THIS LOW...WITH TEMPS IN THE
LOWER 70S AND DEWPS IN THE LOWER 50S UP TO ALMOST THE IA BORDER.
FOR THE WEATHER TONIGHT...LEANED MOST TOWARD THE 12Z NAM FOR
TIMING PRECIP IN AND ACROSS THE AREA AS THIS IS A GOOD
CONTINUATION OF WHAT THE RAP HAS BEEN SHOWING. RIGHT NOW...SEEING
IMPRESSIVE FGEN BAND SETTING UP ACROSS NE SODAK INTO NW MN...AND
LOOKING AT RAP H7-H6 FGEN FORECAST...SHOULD SEE AN INTENSE BAND OF
SNOW SET UP FROM NEAR ABERDEEN UP TO DETROIT LAKES. WITHIN THE
CENTER OF THE BAND SHOULD SEE A GOOD 4 TO 6 INCHES OF SNOW. FOR
THE MPX AREA...FAR NW CORNERS OF OUR FAR NW COUNTIES SHOULD GET IN
ON THE SRN FRINGE OF THIS BAND...WITH A COUPLE OF INCHES OF SNOW
BEING POSSIBLE. FOR SNOW POTENTIAL IN THE WEST...WILL HAVE TO WHAT
HAPPENS WITH A SECONDARY SHORT WAVE THAT SNEAKS UP WEST OF THE SFC
LOW LATE TONIGHT INTO TUESDAY MORNING. THE GEM WAS THE MOST
BULLISH WITH THIS WAVE...BRING A QUICK 2-3 INCHES OF SNOW TO WRN
MN. DID NOT PUT MUCH STOCK IN IT...BUT NOTICING THAT TOWARD THE
END OF RECENT RAP RUNS IT HAS BEEN SHOWING THIS SECONDARY BAND
SNEAKING IN AS WELL...SO WILL NEED TO WATCH THIS OVERNIGHT TO SEE
IF THE WINTER WEATHER ADVISORY NEEDS TO BE PULLED SOUTH.
OUTSIDE OF THE NW CWA...SOUNDINGS SHOW WHATEVER HAPPENING TONIGHT
TO BE DRIZZLE OR LIGHT RAIN...WITH ATMO ABOVE ABOUT H8 BEING DRY...
AND LITTLE OR NO SATURATION BEING SEEN IN THE DENDRITIC GROWTH
ZONE. SHOULD SEE DZ/RA RAPIDLY SPREAD NORTH AFTER 00Z AS STRONG
LOW LEVEL THETA-E ADVECTION WORKS IN. AT THE NOSE OF THE LLJ...THE
RAP IS EVEN INDICATING SOME THUNDER BEING POSSIBLE IN THE EAU AREA
AROUND MIDNIGHT AS BEST LIS DROP TO AROUND -1. 18Z HRRR
REFLECTIVITY FORECAST LOOKS CONVECTIVE IN THIS AREA AS WELL. OF
COURSE WITH ALL OF THIS PRECIP THE KEY WILL BE SFC TEMPS. THE
ENTIRE CWA CURRENTLY SITS BETWEEN 32 AND 36 AND WITH CONTINUED
SOUTHEAST FLOW THROUGH THE NIGHT...DO NOT EXPECT THESE TO CHANGE
MUCH...IN FACT...TEMPERATURES MAY CONTINUE TO RISE RIGHT THROUGH
THE NIGHT ACROSS THE SE CWA. BECAUSE OF THESE MILD
TEMPERATURES...WAS NOT TOO INCLINED TO ISSUE A FREEZING RAIN ADVY
WITH IT BEING QUESTIONABLE IF TEMPS FALL BELOW FREEZING. IN
ADDITION...WITH P-TYPE MAINLY BEING DZ...NOT EXPECTING MANY IMPACTS
WITH DZ AND TEMPS IN THE 30S WITH ALREADY WET SFCS IN PLACE DUE TO
MELTING TODAY. MAKE IT DRY WITH TEMPS IN THE 20S...AND IT WOULD BE
A DIFFERENT STORY...BUT THAT IS NOT WHAT WE ARE DEALING WITH.
WHERE THE HIGHEST POTENTIAL FOR MEANINGFUL FZRA EXISTS WOULD BE IN
THE FAR NE CWA...WHERE THERE WILL BE THE POTENTIAL FOR RAIN THIS
EVENING ON THE NOSE OF THE LLJ.
AS FOR THE FOG...THERE IS NOTHING BUT A SEA OF DENSE FOG FROM SRN
MN DOWN ACROSS IA AND ERN NEB. THIS WILL ADVECT RIGHT BACK NORTH
THIS EVENING...WITH WIDESPREAD FOG EXPECTED AGAIN...AS SEEN WITH
THE GRIDDED LAMP...HRRR...AND WRF-NMM. FOG SHOULD IMPROVE LATE
TONIGHT FROM WEST TO EAST AS AN INVERTED TROUGH/COLD FRONT WORKS
ACROSS MN. FOR SIMPLICITY SAKE...RAN THE FOG ADVY THROUGH 10 AM
TUESDAY MORNING EVERYWHERE...BUT CONDITIONS SHOULD IMPROVE
EARLIER THAN THAT IN WRN MN.
PRECIPITATION SHOULD MOSTLY COME TO AN END BY TUESDAY AFTERNOON
ACROSS THE AREA AS DRY ARCTIC HIGH BEGINS BUILDING IN. STILL SOME
DISAGREEMENT WITH PRECIP POTENTIAL TUESDAY NIGHT AS ANOTHER SFC
LOW RIPPLES NORTH ALONG THE FRONT FROM THE TULSA AREA UP TO MID
MICHIGAN. HUNG SOME CHANCE POPS BACK ACROSS ERN AREA TO ACCOUNT
FOR THE OFF CHANCE THAT SOME SNOW DEVELOPS WEST OF THE LOW. NOT ALL
THAT EXCITED ABOUT SNOW POTENTIAL ON THE BACK SIDE OF THIS SYSTEM
TUESDAY NIGHT INTO WEDNESDAY DUE TO THE FACT THAT UPPER FLOW WILL
BE NEARLY PARALLEL TO THE FRONTAL BOUNDARY. THIS WILL LIKELY KEEP
A COLD CONVEYOR BELT FROM DEVELOPING TO THE NORTH AND NORTHWEST OF
THE LOW AS IT WORKS UP ALONG THE FRONT...WITH MOST ACTIVITY STAYING
NEAR THE FRONT...AND NOT WORKING BACK TOWARD THE EAU AREA.
OF COURSE THE BIG STORY FOR WEDNESDAY THROUGH FRIDAY WILL BE THE
ARRIVAL OF ANOTHER SIGNIFICANT CHUNK OF ARCTIC AIR. TEMPERATURES
WILL BE NEARLY STEADY OR FALLING MUCH OF WEDNESDAY AFTERNOON...AND
BY WEDNESDAY NIGHT...THE COMBO OF TEMPS FALLING TO BELOW ZERO ON
15 TO 25 MPH NW WINDS WILL BRING BACK THE NEED FOR WIND CHILL
ADVISORIES FROM WEDNESDAY NIGHT RIGHT INTO FRIDAY MORNING.
AFTER FRIDAY...TEMPERATURES WILL MODERATE BACK CLOSER TO AND EVEN A
LITTLE ABOVE NORMAL BY THE END OF THE WEEKEND. STILL SEEING THE
POTENTIAL FOR A CLIPPER FRI NIGHT/SATURDAY ON THE ECMWF/GEM...WITH
A COUPLE OF INCHES OF SNOW BEING POSSIBLE ALONG AND NORTH OF I-94.
&&
.AVIATION.../06Z TAF ISSUANCE/
IFR OR LIFR CONDITIONS STILL EXPECTED THROUGH THIS MORNING. THE
MAIN FORECAST UNCERTAINTIES CONTINUE TO BE PRECIPITATION TYPE.
MOST STATIONS ARE AT OR SLIGHTLY ABOVE FREEZING WHICH SHOULD
CONTINUE FOR MUCH OF THE NIGHT IN THE LIGHT SOUTHEAST FLOW. NOT
OVERLY CONCERNED WITH FZDZ OR FZRA DUE TO THE MOIST AIRMASS WHICH
LIMITS ICE ACCRETION AT THESE MARGINAL TEMPERATURES. WITH TIME...A
BAND OF SNOW IS EXPECTED TO DEVELOP ACROSS WEST CENTRAL MN AND THE
BULK OF IT SHOULD REMAIN JUST WEST OF AXN. AS LOW PRESSURE TRACKS
NORTHEAST INTO WISCONSIN TUESDAY MORNING...DRIER AIR WILL BEGIN TO
WORK IN WITH IMPROVING CONDITIONS. THIS COULD ALSO BRING A BETTER
CHANCE FOR -SN OR FZDZ FURTHER EAST.
KMSP...LIFR CONDITIONS EXPECTED THROUG THIS MORNING WITH A GRADUAL
IMPROVEMENT TO MVFR TUESDAY AFTERNOON. PRECIP SHOULD REMAIN IN
LIQUID FORM...BUT WILL NEED TO WATCH TEMPERATURES CLOSELY FOR
POTENTIAL FOR FZDZ LATE TONIGHT. BETTER CHANCE OF SUCH PRECIP WILL
ARRIVE MID MORNING TUESDAY AS COLDER AND DRIER AIR BEGINS TO WORK
IN FROM THE NORTH/NORTHWEST.
/OUTLOOK FOR KMSP/
WED...MVFR WITH POSSIBLE --SN. WIND NW 15-20G30KT.
THU...VFR WITH POSSIBLE MVFR CIGS. WIND NW 10-15G20KT.
FRI...VFR WITH POSSIBLE MVFR CIGS. LGT/VRB WIND.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-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-SWIFT-WASECA-WASHINGTON-WATONWAN-
WRIGHT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR DOUGLAS-
STEVENS-TODD.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR DUNN-EAU CLAIRE-
PEPIN-PIERCE-POLK-ST. CROIX.
FREEZING RAIN ADVISORY UNTIL 9 AM CST TUESDAY FOR BARRON-
CHIPPEWA-RUSK.
&&
$$
MPG/CLF
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1043 PM MST MON JAN 28 2013
.UPDATE...SLOW MOVING BAROCLINIC ZONE AND ASSOCIATED DISTURBED MID
LEVEL JET AXIS CONTINUES TO SHIFT EAST...WITH SNOW SLOWLY TRENDING
EAST OUT OF THE FA. ANOTHER SUBTLE IMPULSE IS EJECTING NE ACROSS
NEB AND WILL SUPPORT CONTINUED SNOW ACROSS FAR SCNTRAL
SD...ALTHOUGH SNOW WILL WANE IN INTENSITY AS THE BEST LIFT AND
BETTER MOISTURE CONTINUES TO SHIFT EAST. HENCE...DROPPED THE WEST
END OF THE ADV...RETAINING THE EASTERN PORTION WHERE ANOTHER 1 TO
2 INCHES OF SNOW IS POSSIBLE INTO EARLY MORNING.
OTHERWISE...ADJUSTED SKY GRIDS GIVEN SOME EXPECTED CLEARING PER
WAKE SUBSIDENCE.
&&
.AVIATION...06Z TAFS
UPPER LEVEL IMPULSE AND ASSOCIATED SNOW WILL CONTINUE TO SHIFT EAST
ACROSS THE REGION. MVFR/IFR CONDITIONS OVER MUCH OF SOUTH CENTRAL
AND CENTRAL SOUTH DAKOTA WILL TREND UP TO HIGH END MVFR AND VFR
THROUGH THE PERIOD AS THIS DISTURBANCE EXITS THE REGION AND SNOW
ENDS EARLY TUES MORNING. VFR CONDITIONS EXPECT MOST PLACES INTO
TUES AFTERNOON. A FAST MOVING CLIPPER SYSTEM WILL PUSH INTO THE
NORTHERN PLAINS TUESDAY AFTERNOON...AFFECTING THE FA NW-SE THROUGH
THE AFTERNOON AND EVENING PERIOD. SNOW WILL BE POSSIBLE OVER MUCH
OF THE REGION...ESP OVER NE WY AND THE NORTHERN BLACK HILLS WITH
MVFR AND POSSIBLE IFR FLIGHT RESTRICTIONS THERE. HAVE ADDED A TREND
TOWARD MVFR AT GCC...WITH RAP EXPECTED TO REMAIN VFR. THE SYSTEM
WILL BRING WINDY CONDITIONS TO THE REGION...ESP IN THE LEE OF THE
BLACK HILLS. HAVE ADDED GUSTY SUSTAINED WINDS AT KRAP TUE EVENING.
.PREV DISCUSSION... /ISSUED 303 PM MST MON JAN 28 2013/
DISCUSSION...WATER VAPOR SHOWS SHARP TROF MOVING INTO THE
ROCKIES...WITH JET ENERGY EJECTING NEWD FROM THE CNTRL ROCKIES
THROUGH THE NRN PLAINS. AT THE SURFACE...LOW CENTER IS DEEPENING
OVER ERN CO WITH LIGHT NLY FLOW ACROSS OUR CWFA. SNOW CONTINUES TO
FALL MAINLY FROM THE BLKHLS EWD.
TONIGHT...BEST LIFT TRANSLATES INTO SCNTRL SD AS NEXT JET STREAK
NOSES THROUGH THE CNTRL PLAINS AND SFC LOW PUSHES EWD ALONG THE
NEB/KS BORDER. STRONG 850-700MB FRONTOGENESIS AND MID LEVEL
INSTABILITY EXPECTED ACROSS SCNTRL SD. 3-5 INCHES OF SNOW
POSSIBLE...ALTHOUGH HIGHER AMOUNTS QUITE POSSIBLE WITHIN HEAVIER
BANDS THAT SET UP. HAVE COVERED WITH A WINTER WX ADVISORY. LIFT/SNOW
SHOULD PUSH EAST OF THE AREA BY DAYBREAK.
TUESDAY...UPPER TROF AXIS SHIFTS INTO THE CNTRL DAKOTAS AS STRONG
SHORTWAVE BEGINS DROPPING DOWN BACK SIDE OF TROF. ARCTIC COLD
FRONT DIVES SOUTHWARD...REACHING NERN WY/WRN SD LATE IN THE DAY.
GUSTY NW WINDS...POSSIBLY REACHING LOWER END ADVISORY ACROSS NWRN
SD...WILL PUSH ACROSS THE AREA TUESDAY AFTN/EVE. WIND CHILLS BY
LATE TUESDAY NIGHT SHOULD DROP UNDER 20 BELOW ZERO ACROSS NWRN SD.
POST FRONTAL LIGHT SNOW/FLURRIES EXPECTED...WITH UPSLOPE
ENHANCEMENT ACROSS THE NRN BLKHLS.
WEDNESDAY...ARCTIC HIGH BUILDS INTO THE DAKOTAS ON
WEDNESDAY...WITH 850-700MB BAROCLINIC ZONE ACROSS NORTHEAST
WYOMING/SOUTHWEST SOUTH DAKOTA. SOME LINGERING LIGHT SNOW/FLURRIES
POSSIBLE...WITH CONTINUING UPSLOPE ENHANCEMENT IN THE NRN BLKHLS.
EXTENDED...ARCTIC AIR WILL HANG AROUND THE AREA ON THURSDAY...
COLDEST NORTH AND EAST OF THE BLACK HILLS...BEFORE BEGINNING TO PUSH
OUT LATE THURSDAY AND THURSDAY NIGHT. LINGERING SNOW IS EXPECTED
ACROSS NORTHEASTERN WY AND FAR WESTERN SOUTH DAKOTA
THURSDAY...ESPECIALLY ACROSS UPSLOPE ENHANCED AREAS OF THE NORTHERN
BLACK HILLS THURSDAY MORNING. SNOW WILL GRADUALLY TAPER OFF THURSDAY
NIGHT...AND EVEN AS LATE AS FRIDAY OVER THE NORTHERN HILLS. THE
ARCTIC BOUNDARY WILL PUSH EAST OF THE AREA FRIDAY BRINGING MUCH
WARMER TEMPERATURES TO THE AREA HEADING INTO THE WEEKEND ALONG WITH
DRY WEATHER.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MELLETTE-TODD-
TRIPP.
WY...NONE.
&&
$$
SHORT TERM...JOHNSON
EXTENDED...13
AVIATION...JC
UPDATE...JC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
627 AM EST TUE JAN 29 2013
...WIDESPREAD DENSE FOG THIS MORNING...
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL TONIGHT INTO WEDNESDAY. A
STRONG COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY...BRINGING
WINDY CONDITIONS AND THE THREAT OF THUNDERSTORMS. AFTER THE COLD
FRONT PUSHES OFFSHORE WEDNESDAY NIGHT...HIGH PRESSURE WILL SUPPORT
COOLER AND DRIER CONDITIONS INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG ADVISORY ALL ZONES UNTIL 10 AM. HIGH RESOLUTION DATA
SUGGESTS FOG MAY LINGER WELL INTO THE MORNING OVER MUCH OF
INTERIOR SOUTHEAST SOUTH CAROLINA WHICH MAY HAVE AN IMPACT ON HIGH
TEMPERATURES. LATEST RAP SUGGESTS TEMPERATURES WILL NOT PEAK MUCH
OUT OF THE MID 60S. NOT READY TO MAKE ANY CHANGES AT THIS
POINT...BUT IT IS A CONCERNING TREND. ALSO...NEW GUIDANCE SUGGESTS
SEA FOG OFFSHORE MAY MOVE INLAND LATE THIS AFTERNOON AND SPREAD
INLAND THIS EVENING. THIS IS NOT SPECIFICALLY ADDRESSED IN THE
FORECAST...BUT AGAIN...THIS TREND WILL HAVE TO BE MONITORED.
TODAY...THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE WILL
EXTEND ACROSS THE SOUTHEAST U.S. TODAY AS A POTENT STORM SYSTEM
MATURES ACROSS THE CENTRAL PLAINS. BROAD WARM AIR ADVECTION
AHEAD OF THIS SYSTEM WILL PUSH H8 TEMPERATURES TO +12-13C WHICH
COUPLED WITH SOME INSOLATION WILL ALLOW HIGHS TO SOAR IN THE MID-
UPPER 70S AWAY FROM THE COAST. AN ONSHORE FLOW OVER THE COLDER
SHELF WATERS WILL TEMPER THERMAL RISES A BIT ROUGHLY EAST OF
HIGHWAY 17 IN SOUTH CAROLINA AND I-95 IN SOUTHEAST GEORGIA WITH
THE BEACHES LIKELY NOT WARMING OUT OF THE UPPER 50S/LOWER 60S.
LOOKS LIKE THE HIGHS AT BOTH THE SAVANNAH AND CHARLESTON AIRPORTS
WILL REMAIN BELOW RECORD TERRITORY--84 SET IN 1957 AT SAVANNAH AND
79 SET IN 2002 AND 1947 AT CHARLESTON.
THE DAY WILL START OUT CLOUDY DUE TO WIDESPREAD FOG AND STRATUS
WHICH WILL DISSIPATE BY MID-MORNING YIELDING AT LEAST PARTLY
CLOUDY SKIES. CLOUDS WILL THEN BEGIN TO INCREASE LATER THIS
AFTERNOON AS ISENTROPIC ASSENT/WARM AIR ADVECTION STRENGTHENS IN
RESPONSE TO AN INTENSIFYING LOW-LEVEL JET. THE CORE OF THE
STRONGEST LIFT LOOKS TO REMAIN DISPLACED WELL TO THE WEST...SO IT
APPEARS THE NAM/S DEPICTION OF ISOLATED TO SCATTERED SHOWERS
FORMING INLAND IS LIKELY TOO AGGRESSIVE PER THE LATEST RAP/H3R
RUNS. WILL KEEP THE FORECAST RAIN FREE FOR NOW WITH GRIDDED POPS
GENERALLY LESS THAN 10 PERCENT.
THERE IS A POSSIBILITY THAT SOME SEA FOG WILL FORM OVER THE COOL
NEARSHORE WATERS THIS AFTERNOON AS DEWPOINTS RISE INTO THE LOWER-
MID 60S. AS SOUTHERLY WINDS INCREASE...THERE IS A POSSIBILITY THAT
SOME OF THIS COULD PUSH INLAND AND AFFECT SOME BEACH COMMUNITIES.
THIS IS CERTAINLY SOMETHING THAT WILL HAVE TO BE WATCHED VERY
CAREFULLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...IT WILL BE A RELATIVELY WARM NIGHT FOR LATE JANUARY
WITH THE REGION PLACED SOLIDLY WITHIN THE WARM SECTOR OF THE
APPROACHING FRONTAL SYSTEM. A STRENGTHENING LOW-LEVEL JET WILL
KEEP THE ATMOSPHERE WELL MIXED WITH THE BOUNDARY LAYER REMAINING
DECOUPLED. LOWS WILL ONLY BOTTOM OUT IN THE LOWER 60S FOR MOST
LOCALES. IT APPEARS THE BEST RAIN CHANCES WILL REMAIN WELL TO THE
WEST CLOSER TO THE FRONT ITSELF...BUT WOULD NOT BE SURPRISED TO SEE
SOME VERY LIGHT SHOWER ACTIVITY DEVELOP OVER THE FAR NORTHERN
ZONES EARLY WEDNESDAY IN THE STRONG WARM AIR ADVECTION REGIME.
WILL KEEP THE FORECAST DRY FOR NOW...ALTHOUGH THE INTRODUCTION OF
AT LEAST ISOLATED SHOWERS MAY BE NEEDED IN LATER FORECAST CYCLES.
WEDNESDAY...THE AXIS OF A ROBUST UPPER TROUGH WILL SWEEP FROM THE
GREAT PLAINS INTO THE OHIO/TENNESSEE VALLEY THROUGH THE
DAY...PROVIDING THE ENERGY TO PUSH A STRONG COLD FRONT INTO THE
FORECAST AREA BY THE LATE AFTERNOON/EARLY EVENING HOURS.
IMPRESSIVE DYNAMICS WILL BE ENHANCING A LINE OF CONVECTION MOVING
EASTWARD WITH THE COLD FRONT...WHILE LATEST NUMERICAL MODEL SOLUTIONS
DELAY THE INTRUSION OF THESE SHOWERS/THUNDERSTORMS UNTIL AT LEAST
21Z TO 00Z. WARM ADVECTION COULD STILL INITIATE SOME ISOLATED TO
SCATTERED SHOWER ACTIVITY AHEAD OF THE FRONT...AND HAVE THUS
INTRODUCED 20 TO 30 PERCENT RAIN CHANCES AS EARLY AS MID MORNING.
RAIN COVERAGE AND INTENSITY WILL THEN GRADUALLY INCREASE FROM
WEST TO EAST AS THE FRONT APPROACHES THE REGION...PEAKING IN THE
EVENING/NIGHTTIME PERIOD. THE MAIN QUESTION THEN BECOMES THE
POTENTIAL FOR SEVERE WEATHER LATE WEDNESDAY.
STORM PREDICTION CENTER HAS MAINTAINED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THE FORECAST AREA ON WEDNESDAY. DYNAMICS ASSOCIATED
WITH THE APPROACHING FRONTAL SYSTEM ARE CONCERNING...AS A 50 TO
60 KT LOW LEVEL JET MOVES DIRECTLY OVER THE AREA BY THE EVENING
HOURS. THE AXIS OF THE UPPER JET WILL BE DELAYED TO THE
WEST...HOWEVER THE FORECAST AREA WILL STILL BECOME LOCATED UNDER
110 TO 120 KT FLOW ALOFT ALONG THE EASTERN PERIPHERY OF THE JET.
SHEAR PROFILES WILL THUS BE QUITE STRONG...AND WHEN COMBINED WITH
A TIGHTENED PRESSURE GRADIENT AHEAD OF THE COLD FRONT...PREVAILING
WINDS ACROSS THE FORECAST AREA WILL BE GUSTY EVEN BEFORE STRONGEST
PRECIPITATION ARRIVES. AS TEMPERATURES WARM WELL ABOVE NORMAL INTO
THE UPPER 70S TO NEAR 80 DEGREES...MIXING DURING THE PEAK HEATING
HOURS COULD TAP INTO THE IMPRESSIVE BOUNDARY LAYER WINDS AND
SUPPORT WIND ADVISORY CONDITIONS. HOWEVER...AS THE CONVECTIVE
PRECIPITATION ASSOCIATED WITH THE COLD FRONT APPROACHES...INSTABILITY
AND LAPSE RATES STILL APPEAR MARGINAL AT BEST. THIS LENDS SOME
UNCERTAINTY TO THE POTENTIAL FOR STORMS TO BECOME SEVERE AND
PRODUCE DAMAGING WINDS GUSTS. DUE TO THE STRONG DYNAMICS FOR
FORCING...WILL MAINTAIN MENTION OF A SLIGHT CHANCE FOR
THUNDER...YET REMAIN SOMEWHAT CONSERVATIVE DUE TO THE INHERENT
ISSUES OF HIGH SHEAR/LOW INSTABILITY ENVIRONMENTS. WILL MAINTAIN
MENTION OF SEVERE POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK TO
ADDRESS THE POSSIBILITY OF AT LEAST ISOLATED SEVERE THUNDERSTORM
DEVELOPMENT.
WEDNESDAY NIGHT AND THURSDAY...THE UPPER TROUGH WILL LIFT AND
FLATTEN BY WEDNESDAY NIGHT...WITH THE COLD FRONT RAPIDLY MOVING
OFFSHORE BY DAYBREAK THURSDAY. PRECIPITATION POTENTIAL PEAKING
BEFORE MIDNIGHT WILL QUICKLY DECREASE FROM WEST TO EAST DURING THE
PRE DAWN HOURS...WITH RAIN CHANCES BELOW 15 PERCENT BY SUNRISE.
DRY HIGH PRESSURE WILL BUILD BEHIND THE DEPARTING SYSTEM...AND
STRONG COLD ADVECTION WILL SUPPORT HIGH TEMPERATURES THURSDAY
AFTERNOON 15 TO 20 DEGREES COOLER THAN THE PREVIOUS DAY. HIGHS
WILL BE SUPPRESSED AROUND 60 DEGREES DESPITE SCATTERING SKY COVER
AND BETTER INSOLATION. CONTINUING COLD ADVECTION AND TIGHTENED
PRESSURE GRADIENTS WILL SUPPORT ANOTHER BREEZY
AFTERNOON...ESPECIALLY AS BETTER MIXING UNDER CLEARING SKIES TAPS
INTO BOUNDARY LAYER FLOW. LOW TEMPERATURES THURSDAY NIGHT WILL
ALSO REFLECT THE SIGNIFICANT CHANCE IN AIR MASS...WITH
TEMPERATURES FALLING INTO THE LOW 30S INLAND TO THE MID/UPPER 30S
CLOSER TO THE COAST.
FRIDAY...HIGH PRESSURE WILL BE REINFORCED FROM THE NORTH...AND
WITH NEARLY ZONAL FLOW ALOFT...EXPECT ANOTHER DRY AND COOL DAY.
TEMPERATURES WILL RANGE RIGHT AROUND SEASONAL NORMALS FOR EARLY
FEBRUARY...PEAKING AROUND 60 DEGREES UNDER MOSTLY SUNNY SKIES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AN UPPER LEVEL SHORTWAVE WILL AMPLIFY AS IT SLIPS SOUTHEAST INTO
THE REGION ON SATURDAY...ALLOWING A WEAK WAVE OF LOW PRESSURE AND
COLD FRONT TO MOVE ACROSS THE MID ATLANTIC AND SOUTHEAST STATES.
DEEP MOISTURE AND DYNAMICS WILL BE MUCH MORE LIMITED WITH THIS
SYSTEM...AND HAVE THUS MAINTAINED A DRY FORECAST. HIGH PRESSURE
WILL QUICKLY REBUILD BEHIND THE DEPARTING SHORTWAVE AND
FRONT...STEADILY MOVING INTO THE ATLANTIC EARLY NEXT WEEK. A
STRONGER COLD FRONT COULD APPROACH THE FORECAST AREA BY
TUESDAY...HOWEVER WILL KEEP POPS BELOW 15 PERCENT DUE TO TIMING
AND IMPACT UNCERTAINTIES THIS FAR IN ADVANCE. HIGH TEMPERATURES
WILL GENERALLY REACH THE LOW 60S EACH AFTERNOON...WITH LOWS
MODERATING INTO THE UPPER 30S TO LOWER 40S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
BIGGEST CONCERN IS TRYING TO TIME WHEN THE FOG WILL LIFT ABOVE
VARIOUS AIRPORT MINIMUMS. LOOKS LIKE LIFR VSBYS WILL LINGER
THROUGH ABOUT 14Z WITH SOME IMPROVEMENT BETWEEN 14-16Z. ITS
UNCLEAR WHETHER IFR OR MVFR CIGS WILL ESTABLISH THEMSELVES AS THE
FOG LAYER LIFTS...BUT WILL HIGHLIGHT SOME CIGS TO COVER. EXPECT
VFR TO RETURN BY 16-17Z AT BOTH TERMINALS. BIG QUESTION LATE THIS
AFTERNOON AND OVERNIGHT IS WHETHER SEA FOG WILL MOVE INLAND AND
IMPACT THE TERMINALS BY EARLY EVENING. GUIDANCE IS ALL OVER THE
PLACE ON THIS POTENTIAL SO LIMITED CONDITIONS TO MVFR FOR NOW.
COULD SEE MARGINAL LOW-LEVEL WIND SHEAR EARLY WEDNESDAY...BUT WILL
NOT INTRODUCE JUST YET AS IT LOOK MARGINAL.
EXTENDED AVIATION OUTLOOK...WINDY CONDITIONS EXPECTED ON
WEDNESDAY...WITH LOW-LEVEL WIND SHEAR POSSIBLE WEDNESDAY MORNING
BEFORE MIXING INCREASES LATE MORNING. TEMPO MVFR OR LOWER CIGS/
VSBYS ARE POSSIBLE WEDNESDAY EVENING/NIGHT WITH SHOWERS AND/OR
THUNDERSTORMS ALONG A COLD FRONT. EXPECT PREVAILING VFR CONDITIONS
TO RETURN BY THURSDAY INTO THE LATE WEEK PERIOD.
&&
.MARINE...
TODAY...MARINE DENSE FOG ADVISORY FOR THE CHARLESTON HARBOR UNTIL
10 AM AND ALL NEARSHORE LEGS UNTIL 1 PM. WEBCAMS SUGGEST VERY
DENSE FOG HAS DEVELOPED OFFSHORE. THE FOG WILL LIKELY LINGER WELL
INTO THE DAY AS THE FOG WILL REMAIN TRAPPED WITHIN THE STRONG
MARINE LAYER.
LIGHT WINDS WILL BECOME SOUTHERLY AND INCREASE TO 5-10 KT TODAY
AHEAD OF AN APPROACHING COLD FRONT. INCREASING DEWPOINTS OVER THE
CHILLY SHELF WATERS COULD SUPPORT AT LEAST PATCHY SEA FOG OVER THE
NEARSHORE WATERS TODAY. IT REMAINS TO BE SEEN HOW WIDESPREAD ANY
SEA FOG COULD BECOME...BUT A MARINE DENSE FOG ADVISORIES MAY BE
NEEDED AT SOME POINT. SEAS WILL RANGE FROM 2-4 FT...HIGHEST
OFFSHORE WATERS.
TONIGHT...WINDS WILL BEGIN TO INCREASE AS LOW-LEVEL JETTING
INTENSIFIES AHEAD OF THE APPROACHING COLD FRONT. WINDS LOOK TO MAX
OUT AT 15-20 KT ALL WATERS AND LOCAL SWAN OUTPUT SUGGESTS SEAS
WILL REMAIN BELOW 6 FT...SO WILL NOT HOIST A SMALL CRAFT ADVISORY
FOR ANY MARINE LEGS FOR THE TONIGHT PERIOD. ANY SEA FOG COULD
LINGER IN THE NEARSHORE WATERS FOR MUCH OF THE NIGHT.
WEDNESDAY THROUGH SATURDAY...MARINE CONDITIONS WILL RAPIDLY
DETERIORATE ON WEDNESDAY...AS THE PRESSURE GRADIENT TIGHTENS
SIGNIFICANTLY AHEAD OF A COLD FRONT AND AN IMPRESSIVE 50 TO 60 KT
LOW LEVEL JET MOVES OVER THE AREA. DUE TO DECENT CONFIDENCE IN
SECOND AND THIRD PERIOD WIND POTENTIAL...HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS AND THE CHARLESTON HARBOR
BEGINNING 15Z WEDNESDAY. HAVE ALSO RAISED A GALE WATCH FOR THE
OFFSHORE GEORGIA WATERS AT 15Z...WHEN FREQUENT GUSTS ABOVE 34 KT
ARE MOST LIKELY TO INITIATE. GALE CONDITIONS COULD ALSO OCCUR
ACROSS THE NEARSHORE WATERS...ESPECIALLY THE MARINE ZONES ADJACENT
TO CHARLESTON COUNTY...HOWEVER TIMING SUGGESTS THESE CONDITIONS
ARE MORE LIKELY TO BE DELAYED TOWARD WEDNESDAY EVENING OR NIGHT.
WILL THUS HOLD OFF ON A GALE WARNING FOR THE NEARSHORE ZONES AT
THIS TIME. SEAS WILL BUILD AHEAD OF THE FRONT...PEAKING BETWEEN
5-10 FT BEYOND 10 NM FROM THE COAST. ALTHOUGH THE FRONT WILL
RAPIDLY SHIFT OUT OF THE AREA BY THURSDAY MORNING...OFFSHORE WINDS
WILL STILL BE QUITE STRONG IN A LOW LEVEL COLD ADVECTION
PATTERN...AND SMALL CRAFT ADVISORY CONDITIONS COULD LINGER THROUGH
AT LEAST THURSDAY AFTERNOON. WINDS AND SEAS WILL THEN STEADILY
DIMINISH THURSDAY NIGHT...REMAINING BELOW ADVISORY CRITERIA FOR THE
REMAINDER OF THE FORECAST PERIOD WITH HIGH PRESSURE GENERALLY IN
CONTROL.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088-
099>101-114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040-
042>045-047>052.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 7 PM EST THURSDAY
FOR AMZ330-350-352-354.
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
AMZ374.
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330.
&&
$$
ST/79
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
622 AM EST TUE JAN 29 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL TONIGHT INTO WEDNESDAY. A
STRONG COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY...BRINGING
WINDY CONDITIONS AND THE THREAT OF THUNDERSTORMS. AFTER THE COLD
FRONT PUSHES OFFSHORE WEDNESDAY NIGHT...HIGH PRESSURE WILL SUPPORT
COOLER AND DRIER CONDITIONS INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG ADVISORY ALL ZONES UNTIL 10 AM. HIGH RESOLUTION DATA
SUGGESTS FOG MAY LINGER WELL INTO THE MORNING OVER MUCH OF
INTERIOR SOUTHEAST SOUTH CAROLINA WHICH MAY HAVE AN IMPACT ON HIGH
TEMPERATURES. LATEST RAP SUGGESTS TEMPERATURES WILL NOT PEAK MUCH
OUT OF THE MID 60S. NOT READY TO MAKE ANY CHANGES AT THIS
POINT...BUT IT IS A CONCERNING TREND. ALSO...NEW GUIDANCE SUGGESTS
SEA FOG OFFSHORE MAY MOVE INLAND LATE THIS AFTERNOON AND SPREAD
INLAND THIS EVENING. THIS IS NOT SPECIFICALLY ADDRESSED IN THE
FORECAST...BUT AGAIN...THIS TREND WILL HAVE TO BE MONITORED.
TODAY...THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE WILL
EXTEND ACROSS THE SOUTHEAST U.S. TODAY AS A POTENT STORM SYSTEM
MATURES ACROSS THE CENTRAL PLAINS. BROAD WARM AIR ADVECTION
AHEAD OF THIS SYSTEM WILL PUSH H8 TEMPERATURES TO +12-13C WHICH
COUPLED WITH SOME INSOLATION WILL ALLOW HIGHS TO SOAR IN THE MID-
UPPER 70S AWAY FROM THE COAST. AN ONSHORE FLOW OVER THE COLDER
SHELF WATERS WILL TEMPER THERMAL RISES A BIT ROUGHLY EAST OF
HIGHWAY 17 IN SOUTH CAROLINA AND I-95 IN SOUTHEAST GEORGIA WITH
THE BEACHES LIKELY NOT WARMING OUT OF THE UPPER 50S/LOWER 60S.
LOOKS LIKE THE HIGHS AT BOTH THE SAVANNAH AND CHARLESTON AIRPORTS
WILL REMAIN BELOW RECORD TERRITORY--84 SET IN 1957 AT SAVANNAH AND
79 SET IN 2002 AND 1947 AT CHARLESTON.
THE DAY WILL START OUT CLOUDY DUE TO WIDESPREAD FOG AND STRATUS
WHICH WILL DISSIPATE BY MID-MORNING YIELDING AT LEAST PARTLY
CLOUDY SKIES. CLOUDS WILL THEN BEGIN TO INCREASE LATER THIS
AFTERNOON AS ISENTROPIC ASSENT/WARM AIR ADVECTION STRENGTHENS IN
RESPONSE TO AN INTENSIFYING LOW-LEVEL JET. THE CORE OF THE
STRONGEST LIFT LOOKS TO REMAIN DISPLACED WELL TO THE WEST...SO IT
APPEARS THE NAM/S DEPICTION OF ISOLATED TO SCATTERED SHOWERS
FORMING INLAND IS LIKELY TOO AGGRESSIVE PER THE LATEST RAP/H3R
RUNS. WILL KEEP THE FORECAST RAIN FREE FOR NOW WITH GRIDDED POPS
GENERALLY LESS THAN 10 PERCENT.
THERE IS A POSSIBILITY THAT SOME SEA FOG WILL FORM OVER THE COOL
NEARSHORE WATERS THIS AFTERNOON AS DEWPOINTS RISE INTO THE LOWER-
MID 60S. AS SOUTHERLY WINDS INCREASE...THERE IS A POSSIBILITY THAT
SOME OF THIS COULD PUSH INLAND AND AFFECT SOME BEACH COMMUNITIES.
THIS IS CERTAINLY SOMETHING THAT WILL HAVE TO BE WATCHED VERY
CAREFULLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...IT WILL BE A RELATIVELY WARM NIGHT FOR LATE JANUARY
WITH THE REGION PLACED SOLIDLY WITHIN THE WARM SECTOR OF THE
APPROACHING FRONTAL SYSTEM. A STRENGTHENING LOW-LEVEL JET WILL
KEEP THE ATMOSPHERE WELL MIXED WITH THE BOUNDARY LAYER REMAINING
DECOUPLED. LOWS WILL ONLY BOTTOM OUT IN THE LOWER 60S FOR MOST
LOCALES. IT APPEARS THE BEST RAIN CHANCES WILL REMAIN WELL TO THE
WEST CLOSER TO THE FRONT ITSELF...BUT WOULD NOT BE SURPRISED TO SEE
SOME VERY LIGHT SHOWER ACTIVITY DEVELOP OVER THE FAR NORTHERN
ZONES EARLY WEDNESDAY IN THE STRONG WARM AIR ADVECTION REGIME.
WILL KEEP THE FORECAST DRY FOR NOW...ALTHOUGH THE INTRODUCTION OF
AT LEAST ISOLATED SHOWERS MAY BE NEEDED IN LATER FORECAST CYCLES.
WEDNESDAY...THE AXIS OF A ROBUST UPPER TROUGH WILL SWEEP FROM THE
GREAT PLAINS INTO THE OHIO/TENNESSEE VALLEY THROUGH THE
DAY...PROVIDING THE ENERGY TO PUSH A STRONG COLD FRONT INTO THE
FORECAST AREA BY THE LATE AFTERNOON/EARLY EVENING HOURS.
IMPRESSIVE DYNAMICS WILL BE ENHANCING A LINE OF CONVECTION MOVING
EASTWARD WITH THE COLD FRONT...WHILE LATEST NUMERICAL MODEL SOLUTIONS
DELAY THE INTRUSION OF THESE SHOWERS/THUNDERSTORMS UNTIL AT LEAST
21Z TO 00Z. WARM ADVECTION COULD STILL INITIATE SOME ISOLATED TO
SCATTERED SHOWER ACTIVITY AHEAD OF THE FRONT...AND HAVE THUS
INTRODUCED 20 TO 30 PERCENT RAIN CHANCES AS EARLY AS MID MORNING.
RAIN COVERAGE AND INTENSITY WILL THEN GRADUALLY INCREASE FROM
WEST TO EAST AS THE FRONT APPROACHES THE REGION...PEAKING IN THE
EVENING/NIGHTTIME PERIOD. THE MAIN QUESTION THEN BECOMES THE
POTENTIAL FOR SEVERE WEATHER LATE WEDNESDAY.
STORM PREDICTION CENTER HAS MAINTAINED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THE FORECAST AREA ON WEDNESDAY. DYNAMICS ASSOCIATED
WITH THE APPROACHING FRONTAL SYSTEM ARE CONCERNING...AS A 50 TO
60 KT LOW LEVEL JET MOVES DIRECTLY OVER THE AREA BY THE EVENING
HOURS. THE AXIS OF THE UPPER JET WILL BE DELAYED TO THE
WEST...HOWEVER THE FORECAST AREA WILL STILL BECOME LOCATED UNDER
110 TO 120 KT FLOW ALOFT ALONG THE EASTERN PERIPHERY OF THE JET.
SHEAR PROFILES WILL THUS BE QUITE STRONG...AND WHEN COMBINED WITH
A TIGHTENED PRESSURE GRADIENT AHEAD OF THE COLD FRONT...PREVAILING
WINDS ACROSS THE FORECAST AREA WILL BE GUSTY EVEN BEFORE STRONGEST
PRECIPITATION ARRIVES. AS TEMPERATURES WARM WELL ABOVE NORMAL INTO
THE UPPER 70S TO NEAR 80 DEGREES...MIXING DURING THE PEAK HEATING
HOURS COULD TAP INTO THE IMPRESSIVE BOUNDARY LAYER WINDS AND
SUPPORT WIND ADVISORY CONDITIONS. HOWEVER...AS THE CONVECTIVE
PRECIPITATION ASSOCIATED WITH THE COLD FRONT APPROACHES...INSTABILITY
AND LAPSE RATES STILL APPEAR MARGINAL AT BEST. THIS LENDS SOME
UNCERTAINTY TO THE POTENTIAL FOR STORMS TO BECOME SEVERE AND
PRODUCE DAMAGING WINDS GUSTS. DUE TO THE STRONG DYNAMICS FOR
FORCING...WILL MAINTAIN MENTION OF A SLIGHT CHANCE FOR
THUNDER...YET REMAIN SOMEWHAT CONSERVATIVE DUE TO THE INHERENT
ISSUES OF HIGH SHEAR/LOW INSTABILITY ENVIRONMENTS. WILL MAINTAIN
MENTION OF SEVERE POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK TO
ADDRESS THE POSSIBILITY OF AT LEAST ISOLATED SEVERE THUNDERSTORM
DEVELOPMENT.
WEDNESDAY NIGHT AND THURSDAY...THE UPPER TROUGH WILL LIFT AND
FLATTEN BY WEDNESDAY NIGHT...WITH THE COLD FRONT RAPIDLY MOVING
OFFSHORE BY DAYBREAK THURSDAY. PRECIPITATION POTENTIAL PEAKING
BEFORE MIDNIGHT WILL QUICKLY DECREASE FROM WEST TO EAST DURING THE
PRE DAWN HOURS...WITH RAIN CHANCES BELOW 15 PERCENT BY SUNRISE.
DRY HIGH PRESSURE WILL BUILD BEHIND THE DEPARTING SYSTEM...AND
STRONG COLD ADVECTION WILL SUPPORT HIGH TEMPERATURES THURSDAY
AFTERNOON 15 TO 20 DEGREES COOLER THAN THE PREVIOUS DAY. HIGHS
WILL BE SUPPRESSED AROUND 60 DEGREES DESPITE SCATTERING SKY COVER
AND BETTER INSOLATION. CONTINUING COLD ADVECTION AND TIGHTENED
PRESSURE GRADIENTS WILL SUPPORT ANOTHER BREEZY
AFTERNOON...ESPECIALLY AS BETTER MIXING UNDER CLEARING SKIES TAPS
INTO BOUNDARY LAYER FLOW. LOW TEMPERATURES THURSDAY NIGHT WILL
ALSO REFLECT THE SIGNIFICANT CHANCE IN AIR MASS...WITH
TEMPERATURES FALLING INTO THE LOW 30S INLAND TO THE MID/UPPER 30S
CLOSER TO THE COAST.
FRIDAY...HIGH PRESSURE WILL BE REINFORCED FROM THE NORTH...AND
WITH NEARLY ZONAL FLOW ALOFT...EXPECT ANOTHER DRY AND COOL DAY.
TEMPERATURES WILL RANGE RIGHT AROUND SEASONAL NORMALS FOR EARLY
FEBRUARY...PEAKING AROUND 60 DEGREES UNDER MOSTLY SUNNY SKIES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AN UPPER LEVEL SHORTWAVE WILL AMPLIFY AS IT SLIPS SOUTHEAST INTO
THE REGION ON SATURDAY...ALLOWING A WEAK WAVE OF LOW PRESSURE AND
COLD FRONT TO MOVE ACROSS THE MID ATLANTIC AND SOUTHEAST STATES.
DEEP MOISTURE AND DYNAMICS WILL BE MUCH MORE LIMITED WITH THIS
SYSTEM...AND HAVE THUS MAINTAINED A DRY FORECAST. HIGH PRESSURE
WILL QUICKLY REBUILD BEHIND THE DEPARTING SHORTWAVE AND
FRONT...STEADILY MOVING INTO THE ATLANTIC EARLY NEXT WEEK. A
STRONGER COLD FRONT COULD APPROACH THE FORECAST AREA BY
TUESDAY...HOWEVER WILL KEEP POPS BELOW 15 PERCENT DUE TO TIMING
AND IMPACT UNCERTAINTIES THIS FAR IN ADVANCE. HIGH TEMPERATURES
WILL GENERALLY REACH THE LOW 60S EACH AFTERNOON...WITH LOWS
MODERATING INTO THE UPPER 30S TO LOWER 40S.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
FOG IS ALREADY BEGINNING TO FORM AT BOTH TERMINALS EARLY THIS
MORNING. THE FOG IS PRETTY SHALLOW SO FAR WHICH WILL LIKELY RESULT
IN VSBYS BOUNCING FOR A FEW MORE HOURS BEFORE SETTLING DOWN AFTER
09Z ONCE THE FOG LAYERS THICKEN. ANTICIPATE LIFR CONDITIONS TO
IMPACT THE TERMINALS WITH BOTH CIGS AND VSBYS REACHING AIRPORT
MINIMUMS. THERE IS SOME HINT THAT A MID-LEVEL CLOUD DECK AROUND
5000 FT COULD DEVELOP JUST AS THE FOG POTENTIAL PEAKS. IT IS
UNCLEAR WHETHER THIS LAYER WILL FORM...BUT IF IT DOES CONDITIONS
COULD STAY ABOVE AIRFIELD AND POSSIBLY ALTERNATE MINIMUMS. FOR
NOW...WILL SHOW PREVAILING LIFR CONDITIONS AT BOTH TERMINALS BY
09Z AND MAINTAIN THIS UNTIL 14-15Z AFTER WHICH CONDITIONS WILL
IMPROVE TO VFR AS THE FOG LAYER DISSIPATES.
EXTENDED AVIATION OUTLOOK...WINDY CONDITIONS EXPECTED ON
WEDNESDAY...WITH LOW-LEVEL WIND SHEAR POSSIBLE WEDNESDAY MORNING
BEFORE MIXING INCREASES LATE MORNING. TEMPO MVFR OR LOWER CIGS/
VSBYS ARE POSSIBLE WEDNESDAY EVENING/NIGHT WITH SHOWERS AND/OR
THUNDERSTORMS ALONG A COLD FRONT. EXPECT PREVAILING VFR CONDITIONS
TO RETURN BY THURSDAY INTO THE LATE WEEK PERIOD.
&&
.MARINE...
TODAY...MARINE DENSE FOG ADVISORY FOR THE CHARLESTON HARBOR UNTIL
10 AM AND ALL NEARSHORE LEGS UNTIL 1 PM. WEBCAMS SUGGEST VERY
DENSE FOG HAS DEVELOPED OFFSHORE. THE FOG WILL LIKELY LINGER WELL
INTO THE DAY AS THE FOG WILL REMAIN TRAPPED WITHIN THE STRONG
MARINE LAYER.
LIGHT WINDS WILL BECOME SOUTHERLY AND INCREASE TO 5-10 KT TODAY
AHEAD OF AN APPROACHING COLD FRONT. INCREASING DEWPOINTS OVER THE
CHILLY SHELF WATERS COULD SUPPORT AT LEAST PATCHY SEA FOG OVER THE
NEARSHORE WATERS TODAY. IT REMAINS TO BE SEEN HOW WIDESPREAD ANY
SEA FOG COULD BECOME...BUT A MARINE DENSE FOG ADVISORIES MAY BE
NEEDED AT SOME POINT. SEAS WILL RANGE FROM 2-4 FT...HIGHEST
OFFSHORE WATERS.
TONIGHT...WINDS WILL BEGIN TO INCREASE AS LOW-LEVEL JETTING
INTENSIFIES AHEAD OF THE APPROACHING COLD FRONT. WINDS LOOK TO MAX
OUT AT 15-20 KT ALL WATERS AND LOCAL SWAN OUTPUT SUGGESTS SEAS
WILL REMAIN BELOW 6 FT...SO WILL NOT HOIST A SMALL CRAFT ADVISORY
FOR ANY MARINE LEGS FOR THE TONIGHT PERIOD. ANY SEA FOG COULD
LINGER IN THE NEARSHORE WATERS FOR MUCH OF THE NIGHT.
WEDNESDAY THROUGH SATURDAY...MARINE CONDITIONS WILL RAPIDLY
DETERIORATE ON WEDNESDAY...AS THE PRESSURE GRADIENT TIGHTENS
SIGNIFICANTLY AHEAD OF A COLD FRONT AND AN IMPRESSIVE 50 TO 60 KT
LOW LEVEL JET MOVES OVER THE AREA. DUE TO DECENT CONFIDENCE IN
SECOND AND THIRD PERIOD WIND POTENTIAL...HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS AND THE CHARLESTON HARBOR
BEGINNING 15Z WEDNESDAY. HAVE ALSO RAISED A GALE WATCH FOR THE
OFFSHORE GEORGIA WATERS AT 15Z...WHEN FREQUENT GUSTS ABOVE 34 KT
ARE MOST LIKELY TO INITIATE. GALE CONDITIONS COULD ALSO OCCUR
ACROSS THE NEARSHORE WATERS...ESPECIALLY THE MARINE ZONES ADJACENT
TO CHARLESTON COUNTY...HOWEVER TIMING SUGGESTS THESE CONDITIONS
ARE MORE LIKELY TO BE DELAYED TOWARD WEDNESDAY EVENING OR NIGHT.
WILL THUS HOLD OFF ON A GALE WARNING FOR THE NEARSHORE ZONES AT
THIS TIME. SEAS WILL BUILD AHEAD OF THE FRONT...PEAKING BETWEEN
5-10 FT BEYOND 10 NM FROM THE COAST. ALTHOUGH THE FRONT WILL
RAPIDLY SHIFT OUT OF THE AREA BY THURSDAY MORNING...OFFSHORE WINDS
WILL STILL BE QUITE STRONG IN A LOW LEVEL COLD ADVECTION
PATTERN...AND SMALL CRAFT ADVISORY CONDITIONS COULD LINGER THROUGH
AT LEAST THURSDAY AFTERNOON. WINDS AND SEAS WILL THEN STEADILY
DIMINISH THURSDAY NIGHT...REMAINING BELOW ADVISORY CRITERIA FOR THE
REMAINDER OF THE FORECAST PERIOD WITH HIGH PRESSURE GENERALLY IN
CONTROL.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088-
099>101-114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040-
042>045-047>052.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 7 PM EST THURSDAY
FOR AMZ330-350-352-354.
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
AMZ374.
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
811 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS GUSTING TO 20-25 KT DURING THE DAY.
WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A COLD FRONT
MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL NOT BE IN
CLOSE PROXIMITY TO ORD AND MDW UNTIL LATER AFTERNOON.
* HIGH CONFIDENCE IN A PERIOD OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS LATER AFTERNOON INTO EVENING. MEDIUM CONFIDENCE IN
TIMING AND CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019...NOON
TUESDAY TO 4 AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
712 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CEILINGS TODAY.
* A CHANCE OF SHOWERS AND THUNDERSTORMS THOUGH MID AFTERNOON.
* WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS LATER AFTERNOON
THROUGH EVENING.
* SOUTH TO SOUTHWEST WINDS GUST UP TO 25KT DURING THE DAY.
* WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A COLD FRONT
MOVES EAST ACROSS THE AREA.
* RETURN OF LIFR CONDITIONS TONIGHT...MAINLY DUE TO LOW CEILINGS.
TRS
//DISCUSSION...UPDATED 12Z
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIG/VSBY TRENDS.
* MEDIUM CONFIDENCE SCATTERED SHOWERS AND THUNDERSTORMS WILL NOT
BE IN CLOSE PROXIMITY OF THE CHI TERMINALS UNTIL LATER AFTERNOON.
* HIGH CONFIDENCE IN A PERIOD OF RA/+RA WITH EMBEDDED TS LATE
AFTERNOON INTO LATER EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL OF WIDESPREAD RAIN AND
EMBEDDED THUNDERSTORMS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019...NOON
TUESDAY TO 4 AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
438 AM CST TUE JAN 29 2013
.SYNOPSIS...
VERY...VERY ACTIVE WEATHER TODAY. THIS MORNING A SURFACE LOW IS
LOCATED OVER NORTHERN IOWA NEAR KMCW AS OF 10Z...WITH A WARM FRONT
DRAPED FROM IT SOUTHEAST ACROSS THE NORTHERN COUNTIES OF THE
FORECAST AREA...GRADUALLY MOVING NORTH. DENSE FOG IS AFFECTING AREAS
IN THE IMMEDIATE VICINITY OF THE FRONT...THUS THE DENSE FOG ADVISORY
THAT CONTINUES UNTIL 6 AM. DEWPOINTS ON THE SOUTH SIDE OF THIS FRONT
ARE IN THE MID 40S TO MID 50S...WITH TEMPERATURES IN THE UPPER 40S
TO NEAR 60. A STRONG COLD FRONT IS DRAPED SOUTH FROM THE SURFACE
LOW BACK INTO NORTHWEST MISSOURI AND INTO KANSAS...WITH STRONG WEST
WINDS BEHIND IT. IN THE WARM SECTOR WE HAVE SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY...WHICH HAS SO FAR PRODUCED MAINLY SMALL HAIL
REPORTS. ..LE..
&&
.SHORT TERM...TODAY...
TODAY IS GOING TO BE A VERY BUSY DAY AS WELL...WITH THE COLD FRONT
SLOWLY BEGINNING TO PLOW INTO THE FORECAST AREA WITH THIS VERY WARM
MOIST AIRMASS IN PLACE. THIS MORNING THE WARM FRONT SHOULD PUSH
NORTH OF THE FORECAST AREA FAIRLY EARLY...ALLOWING THE FOG TO
DISSIPATE. THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY IS JUST THE
SECOND WAVE OF ACTIVITY THAT CAN BE EXPECTED TO AFFECT THE AREA WITH
THIS EVENT. SCATTERED ACTIVITY WILL LIKELY CONTINUE TO MOVE ACROSS
THE FORECAST AREA THIS MORNING. HOWEVER THIS AFTERNOON THE FRONT
SHOULD REALLY LIGHT UP. THIS ALREADY WARM AIRMASS IS LIKELY TO
DEVELOP MUCAPE VALUES OF 500-1000J/KG WITH HIGH TEMPERATURES IN THE
60S IN THE WARM SECTOR. THEN...A NICE SHORTWAVE AND EXIT REGION OF
AN UPPER LEVEL JET COME ACROSS THIS NICE WARM AIRMASS...WE ARE GOING
TO GET WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT. REFER TO THE
SPC DAY 1 OUTLOOK FOR DETAILS...BUT IN THIS AREA WE ARE LOOKING AT
STORMS WITH STRONG WINDS AND SMALL HAIL AS THE MAIN THREAT.
THUNDERSTORMS WITH THIS ACTIVITY WILL BE TAPPING INTO VERY HIGH
PRECIPITABLE WATER VALUE AIR FOR THIS TIME OF YEAR...AND HEAVY
RAINFALL IS EXPECTED THIS AFTERNOON AND EVENING. SEE THE HYDRO
SECTION BELOW FOR MORE INFORMATION. HAVE ALREADY MENTIONED HIGH
TEMPERATURES...WHAT I HAVE FORECASTED FOR TODAY IS GOING TO BREAK
RECORDS. UPSTREAM IN MISSOURI YESTERDAY HIGH TEMPS ROSE INTO THE 70S
NEARLY EVERYWHERE...SO DO NOT THINK THAT HIGHS IN THE MID-UPPER 60S
IS UNREASONABLE GIVEN THE AIRMASS THAT WE WILL HAVE. ..LE..
.LONG TERM...TONIGHT THROUGH NEXT SATURDAY...
A VERY INTERESTING FCST TONIGHT THROUGH WEDNESDAY NIGHT WITH
TEMPERATURES FALLING THROUGHOUT THE ENTIRE TIME FRAME.
THE COLD FRONT WILL BE EAST OF THE MISSISSIPPI BY THIS EVENING.
NUMEROUS SHOWERS/THUNDERSTORMS WILL BE SEEN AHEAD OF THE FRONT WITH
HEAVY RAIN INTO THE FIRST PART OF THE EVENING. BY MID EVENING
TEMPERATURES MAY HAVE FALLEN ENOUGH TO ALLOW A MIX TO DEVELOP OVER
THE NORTHWEST THIRD OF THE CWFA. AS TEMPERATURES CONTINUE TO FALL
THE RAIN WILL CHANGE OVER TO SNOW OVER ROUGHLY THE NORTHWEST 60
PERCENT OF THE CWFA BY SUNRISE WEDNESDAY. A MIX OR JUST RAIN WILL BE
OCCURRING OVER THE FAR EAST/SOUTHEAST.
ON WEDNESDAY...THE DEFORMATION ZONE ASSOCIATED WITH THE SFC LOW WILL
MOVE ACROSS ROUGHLY THE NORTHWEST 40 PERCENT OF THE CWFA. THE TIME
PERIOD JUST PRIOR TO DAWN AND THROUGH MID DAY WILL BE WHEN MOST OF
THE SNOW ACCUMULATION OCCURS.
STRONG CAA BEHIND THE DEPARTING LOW ON WEDNESDAY WILL RESULT IN A
HIGH TEMPERATURE FOR THE DAYLIGHT HOURS OCCURRING JUST AFTER
SUNRISE. TEMPERATURES WILL FALL FOR THE REMAINDER OF THE DAY. WINDS
WILL BE QUITE STRONG WHICH WILL REDUCE VISIBILITIES IN RURAL AREAS.
BY LATE WEDNESDAY AFTERNOON THE SNOW WILL SLOWLY TAPER TO FLURRIES
THAT WILL END DURING THE EVENING HOURS. LATE WEDNESDAY NIGHT WILL BE
DRY AS THE CANADIAN/ARCTIC HIGH BEGINS BUILDING INTO THE MIDWEST.
AS FOR SNOW AMOUNTS...AREAS GENERALLY WEST OF A DUBUQUE TO
WILLIAMSBURG LINE SHOULD SEE 3-4 INCHES WITH POSSIBLY A FEW 5 INCH
AMOUNTS. SOUTHEAST OF THAT LINE AND UP TO A FREEPORT IL TO MEMPHIS
MO LINE 2-3 INCHES ARE EXPECTED. SOUTHEAST OF A FREEPORT TO MEMPHIS
LINE 1-2 INCHES ARE EXPECTED.
DRY BUT COLD CONDITIONS WILL BE SEEN THURSDAY/THURS NIGHT AS THE
CANADIAN/ARCTIC HIGH BUILDS INTO THE MIDWEST.
FRIDAY ON...
MODEL CONSENSUS HAS DRY CONDITIONS ON FRIDAY AHEAD OF AN APPROACHING
CLIPPER SYSTEM. THIS SYSTEM WILL MOVE THROUGH THE AREA FRIDAY NIGHT
AND SATURDAY. THE CURRENT MODEL CONSENSUS SCHC POPS LOOKS REASONABLE
AS WHERE THE CLIPPER TRACKS IS DEPENDENT UPON HOW DEEP THE LONGWAVE
TROF OVER THE EASTERN CONUS BECOMES.
SUNDAY THROUGH MONDAY THE MODEL CONSENSUS CURRENTLY HAS DRY
CONDITIONS WITH MODERATING TEMPERATURES. HOWEVER...THERE ARE SEVERAL
DISTURBANCES MOVING THROUGH IN THE FLOW ALOFT WITH YET ANOTHER
CLIPPER TYPE SYSTEM. MOISTURE AVAILABILITY IS QUESTIONABLE SO THE
CURRENT DRY FCST LOOKS REASONABLE FOR NOW. ..08..
&&
.AVIATION... /ISSUED 1142 PM CST MON JAN 28 2013/
WARM FRONT LIFTING NORTH THROUGH IOWA/ILLINOIS WILL RESULT IN
VLIFR CONDITIONS IMPROVING TO VFR. PRIOR TO AND FOR AN HOUR OR TWO
BEHIND THE FRONTAL PASSAGE LLWS IS LIKELY. RAP MODEL TRENDS
SUGGEST NEW CONVECTION WILL DVLP THROUGH 12Z/29 WITH SOME TSRA
POSSIBLE. COLD FRONT TO MOVE THROUGH EASTERN IOWA/ILLINOIS FROM
15Z/29 TO 00Z/30 BRINGING ANOTHER THREAT OF TSRA. VFR CONDITIONS
WILL DETERIORATE TO MVFR FOLLOWING THE PASSAGE OF THE COLD FRONT.
AFT 06Z/30 CONDITIONS WILL DETERIORATE TO IFR/LIFR WITH SN. ..08..
&&
.HYDROLOGY...
AIRMASS THAT IS NOW IN PLACE OVER THE FORECAST AREA THIS MORNING HAS
COPIOUS MOISTURE...WITH DEWPOINTS IN THE MID 50S. LAST NIGHTS UPPER
AIR SOUNDINGS SHOWED THAT THE ENTIRE ATMOSPERE IS FAIRLY WELL LOADED
WITH MOISTURE...WITH PRECIPITABLE WATER VALUES THAT ARE 200-300
PERCENT OF NORMAL FOR THIS TIME OF YEAR. QPF FROM THE THUNDERSTORMS
ALONG AND AHEAD OF THE COLD FRONT IS LIKELY TO RANGE FROM 1 TO 2
INCHES OVER ABOUT THE SOUTHEASTERN THIRD TO HALF OF THE FORECAST
AREA. CURRENT TIMING INDICATES THAT THIS WILL FALL IN THE AFTERNOON
AND EVENING AS THE COLD FRONT PUSHES THROUGH THE AREA.
GIVEN THIS SCENARIO...THE ROCK RIVER BASIN IS AT GREATEST RISK FOR
POSSIBLE FLOODING...THOUGH THERE IS MUCH UNCERTAINTY OF HOW THE VERY
LOW RIVER LEVELS DUE TO THE RECENT DROUGHT AND THE FROZEN GROUND
WILL REACT ONCE THIS RAIN FALLS ON IT. AN ALMOST GREATER THREAT
WILL BE FLOODING OF URBAN AREAS AND SMALL STREAMS DUE TO HEAVY
RAINFALL RATES IN THE STRONGEST THUNDERSTORMS THIS AFTERNOON AND
EVENING. ..LE..
&&
.CLIMATE...
RECORD HIGHS FOR JANUARY 29...
MOLINE.........57 IN 1914
CEDAR RAPIDS...53 IN 1919
DUBUQUE........54 IN 1914
BURLINGTON.....59 IN 1917
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR BENTON-
BUCHANAN-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
FOR CEDAR-DUBUQUE-JACKSON-JEFFERSON-JOHNSON-JONES-
WASHINGTON.
WINTER STORM WATCH FROM THIS EVENING THROUGH WEDNESDAY AFTERNOON
FOR BENTON-BUCHANAN-DELAWARE-IOWA-KEOKUK-LINN.
FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR DES
MOINES-LEE.
IL...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR CARROLL-
JO DAVIESS-STEPHENSON.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
FOR JO DAVIESS.
FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR BUREAU-
HANCOCK-HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK
ISLAND-WARREN-WHITESIDE.
MO...FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR CLARK.
&&
$$
LE/08
AREA FORECAST DISCUSSION
NWS PUEBLO CO
302 PM MST TUE JAN 29 2013
.SHORT TERM...
(TONIGHT AND WEDNESDAY)
SNOW HAS BEEN WINDING DOWN ACROSS THE SOUTHEAST MOUNTAINS/I-25
CORRIDOR AS FOCUS FOR HEAVIER SNOW SHIFTS EASTWARD ACROSS THE PLAINS
AHEAD OF THE MAIN UPPER TROF AXIS. SNOWFALL REPORTS THAT HAVE COME
IN SO FAR HAVE INDICATED 2 TO 5 INCHES ACROSS THE LOWER EASTERN
SLOPES OF THE SE MTS AND ADJACENT I-25 CORRIDOR. GOBBLERS KNOB WEB
CAM IN SOUTHERN PROWERS COUNTY STARTING TO PICK UP SOME HEAVIER SNOW
AS OF 2 PM...WITH GROUND NEARLY SNOW COVERED.
FOCUS FOR HEAVIER SNOW WILL CONTINUE TO SHIFT SOUTH AND EASTWARD
THROUGH THE LATE AFTERNOON AND EARLY EVENING. STILL THINKING
GENERALLY 1-3 INCHES OF SNOWFALL FOR THE SOUTHEAST PLAINS GENERALLY
TO THE SOUTH AND EAST OF KLHX. THE HEAVIEST WILL FALL ALONG THE
NORTHERN SLOPES OF THE RATON MESA AND ACROSS BACA COUNTY. WHILE 18Z
NAM CONTINUES TO DEPICT A BAND OF HEAVIER SNOW AMOUNTS OF 1 TO 3
INCHES ACROSS BACA/LAS ANIMAS...THE RAP HAS BACKED OFF ON THIS AND
NOW PLACES THE BAND WELL TO THE SOUTH OF THE AREA. HRRR ALSO
APPEARS TO HAVE BACKED OFF ON SNOW AMOUNTS ACROSS BACA COUNTY...SO
WILL HOLD OFF ON ISSUING ANY HIGHLIGHTS AT THIS POINT AND STICK WITH
THE GENERALLY 1-3 INCH AMOUNTS. WITH INSTABILITY STILL IN PLACE WITHIN THE
TROF AXIS...THERE STILL COULD BE SOME LINGERING SNOW SHOWERS BEHIND
THE TROF AXIS THROUGH THE EVENING...THUS WILL KEEP SCATTERED POPS IN
AND NEAR THE MOUNTAINS UNTIL 06Z.
MEANWHILE...ALTHOUGH HEAVIER SNOW WILL BE TAPERING
OFF...NORTHWESTERLY OROGRAPHICS AND INCREASING WINDS ALOFT ON THE
BACK SIDE OF THE UPPER TROF WILL KEEP WIDESPREAD LIGHT TO MODERATE
SNOW GOING ALONG THE SAWATCH AND MOSQUITO RANGES THROUGH THE
NIGHT...WITH THE WIND CAUSING SOME AREAS OF BLOWING SNOW. WITH
TEMPERATURES FALLING INTO THE NEGATIVE READINGS OVERNIGHT...MAY ALSO
SEE SOME WIND CHILL ADVISORY READINGS IN THE -25 TO -34 DEGREE
RANGE. PREVIOUS SHIFT ISSUED A LONG DURATION WINTER WEATHER
ADVISORY FOR THIS AREA...AND THIS STILL LOOKS GOOD...THOUGH HIGHEST
IMPACT MAY BE DUE TO MORE BLOWING SNOW INITIALLY. WILL ADD MENTION
OF THE WIND CHILL VALUES TO THE UPDATED WSW. MAY ALSO SEE WIND
CHILL ADVISORY VALUES ACROSS THE HIGHER ELEVATIONS OF THE EASTERN
SAN JUAN AND LA GARITA MOUNTAINS...THOUGH GIVEN THE SPOTTY NATURE
WILL HOLD OFF ON ISSUING A WIND CHILL ADVISORY AT THIS POINT.
TRAILING SHORTWAVE ENERGY DROPPING IN ON WEDNESDAY SHOULD ENHANCE
SNOWFALL AGAIN ACROSS THE CENTRAL MOUNTAINS WEDNESDAY AFTERNOON.
SHOULD SEE 24 HOUR ACCUMULATIONS OF 2 TO 8 INCHES THROUGH WEDNESDAY
AFTERNOON FOR THIS AREA. ELSEWHERE WX WILL BE PRIMARILY DRY. GUSTY
NORTHWEST 20-40 MPH WINDS WILL MIX DOWN INTO THE LOWER ELEVATIONS
AND ADJACENT I-25 CORRIDOR WEDNESDAY AFTERNOON WHERE GUSTS TO AROUND
20-30 MPH WILL BE POSSIBLE. SNOW COVER WOULD BODE FOR KEEPING TEMPERATURES
ON THE COOL SIDE OF GUIDANCE TOMORROW...THOUGH WITH THE WINDS AND
SOME MIXING...THEY SHOULD MANAGE TO WARM ABOVE FREEZING ACROSS MOST
OF THE PLAINS. LEANED MAX TEMPS TOWARDS THE COOLER SIDE OF GUIDANCE
FOR NOW. MOUNTAIN AREAS WILL SEE HIGHS GENERALLY IN THE TEENS
AND 20S...WITH SOME LOWER 30S ACROSS THE VALLEY AREAS. -KT
.LONG TERM...
(WEDNESDAY NIGHT THROUGH TUESDAY)
WEDNESDAY NIGHT AND THURSDAY...BRISK NW FLOW ALOFT CONTINUES ACROSS
THE REGION THROUGH THURSDAY...WITH MODELS AGREEING ON KEEPING A NEARLY
CONSTANT THREAT OF LIGHT TO MODERATE PCPN OVER THE CENT MTS THROUGH
THE EVE. THOUGH NEW SNOW AMOUNTS WILL ACCUMULATE TO 12 TO 16
INCHES BY THURSDAY AFTN...ANOTHER REAL CONCERN WILL BE THE STRONG
WINDS ALOFT THAT WILL BE EXPERIENCED ACROSS THE HIGHER TERRAIN. A
100 KT CORE OF THE UPPER JET NOSES INTO THE NW QUAD OF COLORADO
THROUGH WEDNESDAY NIGHT...BEFORE MOVING EAST AND WINDS WEAKEN BY
MIDDAY THURSDAY. THEREFORE...ONGOING WINTER WX ADV FOR THE HIGHER
ELEVATIONS OF LAKE AND CHAFFEE COUNTIES LOOKS GOOD. MAX TEMPS ON
THURSDAY ARE EXPECTED TO REBOUND INTO THE 50S FOR THE PLAINS...30S
AND 40S FOR THE HIGH VALLEYS.
FRIDAY AND SATURDAY...TEMPORARY RIDGING ACROSS THE DESERT SW AND
COLORADO TO START THE WEEKEND...WITH DRY AND MILD CONDITIONS
EXPECTED. MODELS DO INDICATE A MINOR UPPER DISTURBANCE ROLLING
ACROSS THE ROCKY MT REGION...BUT CONTINUE TO KEEP THIS FEATURE JUST
NORTH OF THE CWA AND FEEL THAT THE ONLY EFFECT WILL BE AN INCREASE
IN HIGH LEVEL CLOUDINESS. WINDS REMAIN SOMEWHAT LIGHT...SO NO
APPRECIABLE CHANGE IN THE TEMPS IS EXPECTED.
SUNDAY THROUGH TUESDAY...AN UPPER LOW PRES SYSTEM JUST OFF THE S CA
COAST WILL START PUSHING A PLUME OF WARMER PACIFIC MOISTURE UP
ACROSS AZ AND THE 4 CORNERS STARTING ON SUNDAY. AT THE SAME TIME...AN
UPPER DISTURBANCE DROPPING DOWN ACROSS MT AND WY WILL ACT UPON THIS
MOISTURE TAP AND SQUEEZE OUT SOME ISOLATED SHOWERS ALONG THE CONTDVD
LATE SUNDAY. AS THIS FEATURE MOVES EAST AND OUT OF THE
AREA MONDAY...PCPN CHANCE DIMINISH. HOWEVER...LATE MONDAY THE LOW
OFF THE WEST COAST STARTS TO FILL AND MOVE ONSHORE...BRINGING A
SHOT FOR PCPN ONCE AGAIN TO THE CONTDVD STARTING TUESDAY MORNING.
MOORE
&&
.AVIATION...
VFR CIGS ACROSS THE TAF SITES WILL GRADUALLY DIMINISH THROUGH THE
EVENING. THERE COULD BE A LIGHT SNOW SHOWER IN THE VICINITY OF KCOS
THIS EVENING...THOUGH CHANCE LOOKS TOO REMOTE TO WARRANT INCLUSION
IN THE TAF AT THIS POINT. WINDS WILL DECREASE TO UNDER 6 KTS AT KPUB
AND KALS OVERNIGHT...THOUGH KCOS MAY CONTINUE TO SEE SOME ENHANCED
NORTH WINDS IN THE 5-10 KT RANGE THROUGH THE NIGHT.
MEANWHILE...IFR TO LIFR CIGS AND VIS IN -SHSN WILL CONTINUE ALONG
THE CONTDVD...PARTICULARLY ACROSS THE CENTRAL MTS...RESULTING IN
WIDESPREAD MTN OBSCURATIONS. MVFR TO BRIEFLY IFR CIGS WILL CONTINUE
ACROSS THE SOUTHEAST PLAINS THROUGH EARLY EVENING BEFORE THE SNOW
BAND PUSHES SOUTHEAST OF THE AREA OVERNIGHT.
ON WEDNESDAY...VFR CIGS/VIS EXPECTED FOR THE TAF SITES...WITH SOME
BREEZY WEST TO NW WINDS 10-15 KTS POSSIBLE AT KCOS AND KPUB DURING
THE AFTERNOON. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THURSDAY FOR COZ058-060.
&&
$$
31/27
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1119 AM MST TUE JAN 29 2013
.UPDATE...
QUICK UPDATE TO INCREASE POPS FARTHER EAST AND TO DECREASE POPS TO
THE NORTH AND WEST. DISTINCT BACK EDGE TO THE SNOW BAND IS DROPPING
SOUTHWARD INTO NRN PUEBLO COUNTY...AND SNOW IS LIGHTENING UP ALONG
THE LEE OF THE WET MOUNTAINS. ALREADY HAD REPORTS OF 1 TO 3
INCHES FOR EL PASO AND PUEBLO COUNTIES...WITH AROUND 5 INCHES
REPORTED AT BEULAH...AND 4 INCHES AROUND 5 MILES WEST OF
WALSENBURG. THE LOWER EASTERN SLOPES OF THE SE MTS...WETS AND
SANGRES...COULD PICK UP ANOTHER INCH OR TWO...WITH GREATEST
AMOUNTS ACROSS THE SOUTHERN SANGRES AREAS DURING THE EARLY
AFTERNOON. MAIN CONCERN IS SHIFTING TO THE SOUTHEAST PLAINS. SOME
OF THE HIGH RES SHORT RANGE MODELS DEPICT A BAND OF 2 TO 4 INCHES
ACROSS BACA COUNTY LATER THIS AFTERNOON...THOUGH RAP IS KEEPING
THIS AXIS TO THE SOUTH OF THE AREA. COULD HIT LOW END ADVISORY
THRESHOLDS OUT THAT WAY...BUT BREVITY OF THE STORM MAY LIMIT
SNOWFALL ACCUMS TO JUST BELOW CRITERIA AS THE SYSTEM PULLS EAST OF
THE AREA AFTER 00Z. LAPSE RATES ARE QUITE IMPRESSIVE...WHICH IS
WHY SNOWFALL HAS BEEN HEAVY AT TIMES. INSTABILITY IS ALWAYS A WILD
CARD IN SCENARIOS LIKE THIS ONE AND CAN RESULT IN LOCALLY HEAVY
SNOWFALL AMOUNTS. WILL CONTINUE TO MONITOR AND MAKE ADJUSTMENTS TO
THE FORECAST AS NEEDED. -KT
&&
.PREV DISCUSSION... /ISSUED 1030 AM MST TUE JAN 29 2013/
AVIATION...
FOR KCOS...SNOW HAS ENDED. CONDITIONS WILL IMPROVE TO VFR.
KPUB...SNOW EXPECTED TO CONTINUE THROUGH ABOUT 19Z AND THEN
DIMINISH. IFR/LIFR UNTIL AROUND 19Z...AND THEN GRADUALLY IMPROVING
TO VFR.
KALS...SNOW SHOWERS WILL BE POSSIBLE THROUGH THE DAY WITH POSSIBLE
MVFR CONDITIONS.
SNOW SHOWERS WILL CONTINUE IN THE MOUNTAINS WITH ISOLATED TO SCATTERED
MVFR/IFR/LIFR CONDITIONS.
THE HEAVIEST SNOW IS YET TO COME FOR THE FAR SOUTHEAST COLORADO
PLAINS...SOUTH AND EAST OF PUEBLO. SNOWFALL EXPECTED TO INCREASE
IN THAT AREA THROUGH THE AFTERNOON WITH SNOW...BLOWING SNOW AND AT
LEAST A FEW INCHES OF ACCUMULATION POSSIBLE. EXPECTING MVFR/IFR/LIFR
CONDITIONS TO DEVELOP ACROSS THE FAR SOUTHEAST PLAINS THIS
AFTERNOON AS SNOWFALL MOVES INTO THE AREA. LW
PREV DISCUSSION... /ISSUED 341 AM MST TUE JAN 29 2013/
SHORT TERM...
(TODAY AND TONIGHT)
.SOME SNOW FOR THE PLAINS...
.SNOW CONTINUING ACROSS THE C MTNS...
CURRENTLY...
FULL LATITUDE TROUGH EXTENDS FROM NORTHERN WY S-SWD INTO S ARIZ.
THIS TROUGH WAS MOVING STEADILY EAST. LOCALLY ON THE PLAINS...ECHOES
WERE INCREASING ACROSS EL PASO COUNTY WITH HIGH LEVEL ECHOES
DEVELOPING OVER THE FAR E PLAINS. SKIES WERE GENERALLY CLOUDY OVER
THE ENTIRE REGION WITH LOW CLOUDS ALONG THE GREATER I-25 CORRIDOR
REGION.
TODAY...
IT PROMISES TO BE AN INTERESTING DAY...HOW INTERESTING WILL BE THE
MAIN QUESTION.
I AM CONFIDENT WE WILL SEE SNOW ACROSS THE PLAINS TODAY. MODELS IN
FAIRLY GOOD AGREEMENT WITH SNOW DEVELOPING THIS MORNING OVER THE
PALMER DIVIDE (AND THIS IS VERIFYING) AND MOVING S/DEVELOPING OVER
THE EASTERN PLAINS AFTER SUNRISE. SHORTER RANGE MODELS ARE NOW
DEVELOPING A SHARP TROUGH AXIS/WEAK CLOSED LOW AT 700 MB OVER THE
FAR SE PLAINS REGION OF CO. THIS WILL SET UP STRONGER LLVL
CONVERGENCE OVER THE E PLAINS AND THIS SHOULD ALLOW A DECENT BAND OF
SNOW TO DEVELOP...WITH THE HEAVIEST PRECIP LIKELY EXTENDING FROM EADS
SSW TOWARDS LAS ANIMAS COUNTY. ADDITIONALLY...WITH THE SHARP LLVL
TROUGH...WINDS AT 700 GO NORTHEASTERLY AND THIS SHOULD FAVOR THE
RATON MESA/S MTNS LATER TODAY. THE COS/PUB AREAS WILL SEE ITS BEST
CHANCE OF SNOW FROM NOW THROUGH LATE MORNING. AS FOR
ACCUMULATIONS...WE COULD SEE 1-2" IN AREAS IN THE PUB/COS AREA. IN
MATTER OF FACT...SOME OF THE HIGH RES MODELS ARE SHOWING MORE SNOW
FOR THE PUB AREA THAN THE SPRINGS. FOR THE FAR E PLAINS...I PUT IN
1-2"...I AM CONCERNED THERE MAY BE LOCALLY MORE IF THE SNOW COMES
DOWN HEAVY ENOUGH. RATON MAY SEE 1-3".
THESE VALUES ARE SOMEWHAT UNCERTAIN...ESPECIALLY FOR THE FAR E
PLAINS. IF THE BAND SETS UP AND STAYS IN PLACE...WE COULD SEE
LOCALLY HIGHER AMOUNTS OVER THE FAR E PLAINS...ESPECIALLY IN AREAS
FROM KIOWA COUNTY S-SE INTO LAS ANIMAS COUNTY.
SNOW OVER THE CONTDVD WILL DECREASE THIS MORNING...ESPECIALLY ACROSS
THE SW MTNS. THE SNOW WILL PICK UP AGAIN ACROSS THE C MTNS THIS
AFTERNOON.
TONIGHT...
PLAINS WILL BE DRY. THERE MAY BE A FEW LINGERING SHOWERS EARLY THIS
EVENING OVER THE FAR E PLAINS...BUT THEY SHOULD MOVE OUT INTO KS
PRETTY QUICKLY. IN ADDITION...WE MAY SEE SOME LINGERING SNOW SHOWERS
OVER THE PALMER DIVIDE DURING THE EVENING HOURS.
FOR THE C MTNS...SNOW WILL CONTINUE TO INCREASE. WE WILL BE ISSUING
ADDITIONAL HILITES FOR THIS REGION AFTER 5 AM THIS MORNING. WE ARE
LEANING TOWARDS A LONG DURATION HILITE STARTING LATER TODAY AND
LASTING POSSIBLY INTO LATE WEEK (THU?). FAVORABLE NW FLOW WILL KEEP
THE SNOW MACHINE GOING FOR AT LEAST A COUPLE OF DAYS ACROSS THE C
MTN REGION. /34
LONG TERM...
(WEDNESDAY THROUGH TUESDAY)
MODELS IN GOOD AGREEMENT HEADING INTO THE WEEKEND WITH DIFFERENCES
BY EARLY NEXT WEEK. TRENDED THE FORECAST WITH THE ECMWF WHICH
SEEMS TO HAVE A BIT BETTER SUPPORT OF THE ENSEMBLE MEMBERS.
THE UPPER LEVEL TROUGH SITTING OVER EASTERN COLORADO WEDNESDAY
MORNING WILL QUICKLY SHIFT EAST INTO THE MISSOURI VALLEY BY
WEDNESDAY AFTERNOON. BOTH THE ECMWF AND NAM HAVE SNOW COMING TO AN
END OVER THE PALMER DIVIDE AND SOUTHERN SANGRE DE CRISTO RANGE
BEFORE SUNRISE WEDNESDAY...WHILE THE GFS WANTS TO HANG ONTO
LINGERING SNOW OVER THESE AREAS THROUGH MUCH OF WEDNESDAY MORNING.
GIVEN THAT THE MODELS SEEM TO FAVOR DRY CONDITIONS...HAVE THE
EASTERN MOUNTAINS AND PALMER DRY BY WEDNESDAY MORNING. ONCE THE
UPPER TROUGH SHIFTS EAST WEDNESDAY AFTERNOON...THE REGION WILL BE
UNDER BROAD NORTHWESTERLY FLOW. EXPECT A PROLONGED PERIOD OF LIGHT
TO MODERATE SNOWFALL ACROSS THE CENTRAL MOUNTAINS THROUGH
THURSDAY. WEST FACING SLOPES WILL LIKELY SEE A GOOD 4 TO 8 INCHES
WEDNESDAY THROUGH THURSDAY WITH LOCALLY HIGHER AMOUNTS POSSIBLE.
WINTER WEATHER HIGHLIGHTS WILL LIKELY BE ISSUED FOR THE HIGHER
ELEVATIONS OF THE CENTRAL MOUNTAINS LATER THIS MORNING.
TEMPERATURES WILL BE COOL ON WEDNESDAY WITH 40S FOR THE LOWER
ELEVATIONS BEFORE REBOUNDING INTO THE MID 50S ON THURSDAY.
NORTHWEST FLOW TURNS MORE WESTERLY THURSDAY NIGHT AHEAD OF A WEAK
SHORTWAVE TROUGH DROPPING SOUTH OUT OF THE NORTHERN ROCKIES. THIS
SHOULD EFFECTIVELY SHUT DOWN SNOWFALL OVER THE CENTRAL MOUNTAINS
BY THURSDAY EVENING. MODELS HANDLE THE WEAK SHORTWAVE DIFFERENTLY.
THE GFS DROPS THE WAVE SOUTH ACROSS COLORADO ON FRIDAY WITH A
PERIOD OF LIGHT SNOWFALL ACROSS THE HIGHER ELEVATIONS FRIDAY
EVENING. THE ECMWF PROVIDES A GLANCING BLOW ACROSS NORTHERN
COLORADO AND KEEPS THE REGION DRY. GIVEN THE CONSISTENCY FROM RUN
TO RUN OF THE ECMWF...HAVE TRENDED WITH IT...WITH DRY CONDITIONS
ON FRIDAY AND FRIDAY NIGHT.
FOR THE LATER HALF OF THE FORECAST PERIOD...HAVE TRENDED WITH THE
ECMWF WHICH HAS BETTER SUPPORT FROM THE ENSEMBLES. HIGH PRESSURE
WILL SHIFT EAST ACROSS COLORADO SATURDAY INTO SUNDAY BEFORE A WEAK
TROUGH OUT OF THE PACIFIC NORTHWEST TRACKS ACROSS THE REGION
SUNDAY NIGHT INTO MONDAY MORNING. TEMPERATURES SHOULD WARM NICELY
FOR THE WEEKEND WITH AT LEAST UPPER 50S TO LOWER 60S ACROSS THE
PLAINS. THERE IS VERY LITTLE MOISTURE TO WORK WITH AND THE
FORECAST LOOKS TO BE DRY AT THIS POINT. HIGH PRESSURE WILL THEN
REBUILD ACROSS THE ROCKIES BY TUESDAY WITH CONTINUED DRY AND MILD
WEATHER. IT SHOULD BE NOTED THAT THE GFS BRINGS A TROUGH INTO THE
REGION LATE SATURDAY THROUGH SUNDAY NIGHT WITH INCREASED CHANCES
FOR SNOWFALL OVER THE MOUNTAIN AREAS...SPREADING EAST INTO THE
PLAINS AS THE SYSTEM PASSES BY. THERE SEEMS TO BE LITTLE SUPPORT
FOR THIS SOLUTION...AND A QUICK LOOK AT THE NEW 06Z RUN HAS REALLY
BACKED OFF ON PRECIPITATION COMPARED TO THE 00Z SOLUTION AND LOOKS
MORE LIKE THE ECMWF. 88
AVIATION...
FOR KCOS...PERIODS OF SNOW WILL OCCUR UNTIL ABOUT LATE MORNING THEN
VFR. LIGHT ACCUMS...ABOUT AN INCH OR SO...ARE POSSIBLE. IFR
CONDITIONS WILL OCCUR IN STEADY PRECIP. WINDS SHOULD NOT BE TOO MUCH
OF AN ISSUE...NNE AT 10-15 KTS DURING THE SNOW. VFR AFTER NOONTIME.
KPUB...COULD SEE SOME SNOW THIS MORNING AND EARLY AFTERNOON. OVC
MVFR/IFR LIKELY. SHOULD CLEAR UP BY EARLY AFTERNOON WITH VFR
CONDITIONS.
KALS...SNOW SHOWERS WILL BE POSSIBLE THROUGH THE DAY WITH POSSIBLE
MVFR CONDITIONS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM MST
THURSDAY FOR COZ058-060.
&&
$$
31/27
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
410 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEWPOINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WINDCHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SCATTERED SHOWERS AND THUNDERSTORMS WILL PERSIST UNTIL AROUND
00Z...THEN A MORE SOLID LINE WILL PASS THROUGH THE TERMINALS
WITH A SHORT PERIOD OF PREVAILING RAIN AND THUNDER. AFTER ARND
02Z...WIDESPREAD RAIN WILL PERSIST THROUGH THE EVENING.
* SOUTH WINDS GUSTING TO ARND 20 KT...SHIFTINGTO SWLY WITH GUSTS
TO 25KT WITH THE MORE SOLID LINE OF SHRA/TSRA. WINDS VEERING WYL
AND NWLY THROUGH THE EVENING. AND OVERNIGHT.
* MVFR CONDITIONS PREVAILING THE REMAINDER OF THIS AFTERNOON AND
INTO THE EVENING...WITH OCNL IFR LIKELY. THEN PREVAILING IFR
CIGS THROUGH THE NIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
EVENING...AND IN CIG/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 10 PM TUESDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 6 AM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
320 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEWPOINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WINDCHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 10 PM TUESDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 6 AM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
245 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
149 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR TO IFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1144 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR TO IFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1112 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
341 PM EST TUE JAN 29 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN
UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 PM EST TUE JAN 29 2013
NUMEROUS WEATHER HAZARDS WILL ACCOMPANY AN EXTREMELY POTENT SYSTEM
IMPACTING THE REGION THROUGH TOMORROW. VERY UNSEASONABLY WARM AND
MOIST CONDITIONS WILL BE IN PLACE THROUGH TONIGHT. AHEAD OF A
STRONG COLD FRONT SWEEPING THROUGH THE REGION...THE POTENTIAL WILL
EXIST FOR THUNDERSTORMS...HEAVY RAINFALL...FLOODING AND DAMAGING
WINDS. POTENTIAL FOR STRONG WINDS WILL CONTINUE BEHIND THE FRONTAL
BOUNDARY ON WEDNESDAY...AND FLOODING MAY LAST FOR SEVERAL DAYS OR
MORE.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 337 PM EST TUE JAN 29 2013
FOCUS OF THE NEAR TERM REMAINS ON SEVERE WEATHER CHANCES AS WELL AS
POSSIBLE HEAVY RAINFALL/FLOODING POSSIBILITIES TONIGHT. THE PERIOD
BEGINS WITH GOOD SHORT TERM MODEL AGREEMENT AS TO THE LOCATION OF
KEY FEATURES THAT MAY BRING POSSIBLE SEVERE TO PORTIONS OF THE
FORECAST AREA TONIGHT. AT 00Z/WED...THE LOW PRESSURE CENTER IS
PROGGED TO BE OVER CENTRAL MISSOURI...WITH ONGOING CONVECTION
POSSIBLY ALREADY IN THE FORM OF A SQUALL LINE ALONG A STRONG COLD
FRONT STRETCHED FROM NORTHWEST ILLINOIS...DOWN THROUGH CENTRAL
MISSOURI...INTO EASTERN OKLAHOMA/WESTERN ARKANSAS.
THERE DOES APPEAR TO BE SOME DIFFERENCES IN SPEED/TIMING OF THE
FRONT INTO THE FORECAST AREA...WITH THE HRRR AND RAP INTO THE AREA A
BIT QUICKER THE THE NAM AND GFS. PERSONAL EXPERIENCE HAS SHOWN THAT
THESE COLD FRONT/SQUALL LINE FEATURES TEND TO COME IN A BIT QUICKER
THAN SOMETIMES EXPECTED. THEREFORE...DECIDED TO TREND TOWARD THE
HRRR/RUC SOLNS.
AS WAS MENTIONED IN PREVIOUS DISCUSSIONS...DYNAMICS WILL NOT BE AN
ISSUE WITH THIS SYSTEM AS THE FRONT APPROACHES. A LOW LEVEL JET AOA
80 KTS AT 850 MB IS EXPECTED TO DEVELOP OUT AHEAD OF THE FRONT THIS
EVENING AND WILL TRANSLATE INTO OUR AREA TONIGHT. WITH 50 KT WINDS
LOCATED APPROXIMATELY 1000-1500 FEET ABOVE THE SURFACE
TONIGHT...DAMAGING WINDS MAY BECOME A REAL THREAT WITH ANY STORMS
THAT ARE ABLE TO REMAIN ORGANIZED AS THEY PUSH INTO THE FORECAST
AREA. ONE LIMITING FACTOR FOR CONVECTION REMAINING ORGANIZED INTO
THE OVERNIGHT HOURS IS INSTABILITY. SFC-BASED CAPE LOOKS TO BE IN
THE UNDER 200 J/KG RANGE...WHILE MUCAPE GIVES SLIGHTLY HIGHER
VALUES OF 200-400 J/KG AS THE FRONT MOVES INTO THE AREA. WITH THE
STRONG DYNAMICS AVAILABLE...WILL CONTINUE DAMAGING WINDS REFERENCE
IN THE GRIDS. ALSO KEEP IN MIND THAT WITH AMPLE LOW LEVEL
SHEAR...0-1 HELICITIES AOA 400-500 M2/S2...AN ISOLATED TORNADO
CANNOT BE RULED OUT.
THE BEST TIMING FOR SEVERE LOOKS TO START AT APPROXIMATELY 04-05Z
ACROSS WESTERN PORTIONS OF THE FORECAST AREA...TO ABOUT 10-11Z OVER
THE EAST. JUST ONE OTHER NOTE TO MENTION...THE HRRR ILLUSTRATES A
LINE OF CONVECTION DEVELOPING OUT AHEAD OF THE MAIN SQUALL LINE. TO
A LESSER EXTENT...THE RAP ALSO DEPICTS A SIMILAR SCENARIO. WHILE
THIS FORECAST HAS TAKEN THIS INTO CONSIDERATION...IT COULD STILL
ALLOW FOR AN EARLIER ONSET THAN FORECAST.
HEAVY RAINFALL IS ALSO IN PLAY TONIGHT AS MOISTURE HAS CONTINUED TO
STREAM NORTH INTO THE AREA. A PACIFIC TROPICAL PLUME OF MOISTURE HAS
BEEN EVIDENT ALL DAY ON WATER VAPOR IMAGERY STREAMING NORTHWEST INTO
LOWER MISSOURI/MID MISSISSIPPI/OHIO RIVER VALLEY STATES. COUPLE THAT
WITH 60 DEGREE DEWPOINTS CURRENTLY ON THE SOUTHWESTERN DOORSTEP OF
THE FORECAST AREA. PWATS TONIGHT AHEAD OF THE FRONT LOOK TO REACH
UPWARDS OF 1.40-1.50 INCHES...YIELDING A PERCENT OF NORMAL OF AROUND
300 PERCENT. WOULD NOT BE SURPRISED TO SEE A WIDESPREAD 1 TO 1.5
INCH RAINFALL...WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 337 PM EST TUE JAN 29 2013
SHORT TERM PERIOD SEES A DIFFERENT SET OF CHALLENGES. ONE OF THE
INITIAL CHALLENGES WILL BE STRONG WINDS AFTER THE COLD FRONT SWEEPS
THROUGH THE AREA AND A DRY SLOT APPROACHES THE FORECAST AREA DURING
THE AFTERNOON HOURS. SUSTAINED WINDS AROUND 20-25 KTS...WITH THE
POSSIBILITY TO TAP 40 KT WINDS FROM APPROX 850 MB AS BOUNDARY LAYER
MIXES OUT. A WIND ADVISORY MAY BE NEED FOR A TIME IN THE LATE
MORNING TO EARLY EVENING HOURS ON WEDNESDAY.
ADDITIONALLY...SOME LIGHT SNOW SHOWERS MAY WRAP AROUND AND AFFECT
MAINLY NORTHERN PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT AS THE
UPPER TROUGH FINALLY PASSES THROUGH. NOT CURRENTLY EXPECTING MUCH IN
THE WAY OF ACCUMULATION.
ANOTHER UPPER TROUGH AND COLD FRONT PUSHES INTO THE THROUGH THE AREA
LATE THURSDAY INTO THURSDAY NIGHT...BRINGING AN ADDITIONAL CHANCE
FOR SNOW AND FALLING TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 144 PM EST TUE JAN 29 2013
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED PERIOD WILL NOT BE NEARLY AS ACTIVE AS THE FIRST FEW
DAYS OF THE FORECAST. FIRST OFF A SHORT WAVE TROUGH MOVING THROUGH
THE GREAT LAKES REGION MAY BRING A FEW SNOW SHOWERS TO CENTRAL
INDIANA AT THE BEGINNING OF THIS PERIOD. TEMPS/THICKNESS ALL LOOK
COLD ENOUGH FOR PLAIN SNOW DURING THIS TIME. ATTM ACCUMULATIONS
APPEAR TO BE AN INCH OR LESS. AFTER A COLD SHOT OF AIR THU AND
FRIDAY...TEMPERATURES WILL GRADUALLY MODERATE TO CLIMO OVER THE
WEEKEND AND INTO NEXT WEEK. SECOND HALF OF THE WEEKEND LOOKS DRY
AND INTO EARLY NEXT WEEK. ENSEMBLES SHOW SOME PRECIP BY NEXT
MONDAY/MONDAY NIGHT. TEMPERATURES LOOK WARM ENOUGH FOR A
SNOW/RAIN MIX ACROSS A GOOD PORTION OF THE AREA. HAVE SMALL
MINIMAL PRECIP CHANCES IN DURING THIS TIME.
&&
.AVIATION /DISCUSSION FOR THE 29/21Z TAF UPDATE/...
ISSUED AT 316 PM EST TUE JAN 29 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
AVIATION FORECAST BASICALLY LOOKS RIGHT ON TRACK WITH ONLY A FEW
MINOR TWEAKS MADE. MVFR CEILINGS THROUGH EARLY EVENING...THEN IFR
CEILINGS AS RA...SCATTERED THUNDERSTORMS AND WIND GUSTS TO 35 KNOTS
DEVELOP LATER TONIGHT. OPTED TO REMOVE MUCH OF THE VCSH AND EVEN
VCTS MENTION THIS AFTERNOON AND PUSH BACK TIMING FOR VCSH TO THIS
EVENING WITH VCTS TO ARRIVE WITH MAIN PUSH AFTER MIDNIGHT, ALONG
WITH MODERATE TO HEAVY RAINFALL. MODELS INDICATE NUMEROUS SHOWERS
AND SCATTERED THUNDERSTORMS WITH COLD FRONT OVERNIGHT. IFR
CEILINGS RAIN AND THUNDERSTORMS SHOULD SPREAD INTO KLAF AND KHUF
THIS EVENING AND ELSEWHERE AFTER MIDNIGHT.
SOUTHERLY WINDS WILL CONTINUE TO INCREASE TO 20 TO 30 KNOTS THIS
AFTERNOON AND EVEN HIGHER WITH COLD FRONT OVERNIGHT. A LOW LEVEL JET
WILL PRODUCE LOW LEVEL WIND SHEAR ONCE AGAIN OVERNIGHT WITH 60 KT
AROUND 2K FT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH WEDNESDAY MORNING
FOR INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...MRD
NEAR TERM...MRD
SHORT TERM...MRD
LONG TERM....SMF
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
551 PM EST TUE JAN 29 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 504 PM EST TUE JAN 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS INTO NEW MEXICO. WEAK SHRTWVS
EMBEDDED IN THE SW FLOW FROM THE SRN PLAINS INTO THE GREAT LAKES
SUPPORTED AREAS OF SHRA/TSRA NEAR A SFC FRONT EXTENDING FROM NE WI
THROUGH CNTRL MO AND INTO CNTRL OK. THE MAIN SHRTWV WAS REMAINED
NEAR THE BASE OF THE TROUGH...MOVING TOWARD THE TX/OK PANHANDLE.
PCPN HAD DIMINISHED OVER UPPER MICHIGAN WITH MAINLY SOME SCT LIGHT
SHOWERS MOVING THROUGH FAR SRN UPPER MI. WEST WINDS AND SLIGHTLY
DRIER AIR BEHIND A TROUGH SLIDING TO NEAR P53-ISQ HAS BROUGHT
IMPROVED VISIBILITIES THROUGH THE CNTRL AND WEST CWA.
ALTHOUGH THE 12Z ECMWF WAS A BIT SLOWER THAN THE 12Z GFS...THE MODELS
WERE IN RELATIVELY GOOD AGREEMENT WITH REGARD TO OVERALL PCPN/SNOW
POTENTIAL ACROSS THE CWA. ALTHOUGH THE 12Z NAM HAD SHIFTED THE
HEAVIER QPF AXIS WELL TO THE EAST...THE 18Z RUN HAS COME BACK INTO
BETTER AGREEMENT WITH THE GLOBAL MODELS. MODELS DIFFICULTY IN
HANDLING THE CONVECTION AND HEAVY RAIN NEAR THE FRONT MAY ACCOUNT
FOR A PORTION OF THE INCONSISTENCY AND VARIABILITY AND STILL LEADS
GREATER THAN USUAL UNCERTAINTY. ALTHOUGH THERE IS MODERATE
CONFIDENCE WITH THE MULTI-MODEL BLEND OF THE GFS/ECMWF/NAM/REG-GEM
USED FOR QPF...TIMING OF THE HEAVIER PCPN ONSET MAY BE A BIT DELAYED
GIVEN ECMWF/NAM TRENDS.
THE STRONGEST DYNAMICS ARE EXPECTED TO DEVELOP BTWN 12Z-18Z/WED AS
THE NM SHRTWV LIFTS TOWARD THE GREAT LAKES. A COUPLED UPPER LEVEL
JET STRUCTURE AND RESULTING STRONG 800-600 MB FGEN WILL SUPPORT A
PERIOD OF MODERATE TO HEAVY PCPN IN THE REGION...WITH THE BEST
CHANCE FOR HEAVY SNOW OVER THE SE HALF OF UPPER MI. EXPECT A SHARP
NW EDGE OF THE PCPN BAND DUE TO STRONG DESCENDING FGEN CIRCULATION
BRANCH WHICH REDUCES CONFIDENCE IN PCPN AMOUNTS THROUGH CNTRL UPPER
MI. QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE WITH SNOW/WATER RATIO
VALUES NEAR 16/1 SUPPORTS GENERALLY 4 TO 8 INCH SYNOPTIC
SNOW...GREATEST OVER THE FAR S AND EAST. LAKE ENHANCED SNOW WILL
GENERALLY BE LIGHT EARLY WED WITH LOW INVERSION HEIGHTS NEAR 4K FT
AND 850 MB TEMPS ONLY NEAR -10C BUT BY WED AFTERNOON SNOWFALL RATES
OVER N CNTRL AND FAR WEST NEAR IWD SHOULD INCREASE AS 850 MB TEMPS
FALL TO NEAR -16C. ALTHOUGH UPSLOPE FLOW SHOULD ENHANCE SNOWFALL
RATES...CYCLONIC 350 FLOW MAY ALSO LEAD TO GREATER AMOUNTS NEAR THE
SHORE WED AFTERNOON.
FCST CONFIDENCE WAS HIGH ENOUGH TO UPGRADE WATCHES TO WARNINGS OVER
THE EAST HALF BUT WITH AMOUNTS ONLY IN THE 2 TO 5 INCH RANGE OVER
MARQUETTE AND DICKINSON COUNTIES THROUGH WED AND PROXIMITY TO THE
EDGE OF THE SYNOPTIC PCPN...AN ADVY WAS ISSUED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 29 2013
INITIAL PART OF THE LONG TERM FORECAST IS HIGHLY DEPENDENT ON THE
TRACK OF THE SHORTWAVE RIDING UP THE UPPER TROUGH OVER THE CENTRAL
CONUS AND THE ASSOCIATED LOW DEVELOPING IN NORTHERN LOWER MI AND
THEN SHIFTING NORTHEAST INTO QUEBEC ON WEDNESDAY NIGHT. THE SHORT
TERM DISCUSSION COVERS MUCH OF THE DETAILS WITH THIS SYSTEM AND THE
MAIN FEATURE TO CAPTURE IN THE LONG TERM WITH THIS SYSTEM IS THE
DIMINISHING TREND IN THE POPS/QPF OVER THE EASTERN CWA.
BEHIND THIS FEATURE...EXPECT COLD AIR TO SURGE SOUTHEAST OVER THE
UPPER GREAT LAKES REGION AND REMAIN INTO THE WEEKEND. THIS COLD
AIR...H850 TEMPS IN THE LOW -20S CELSIUS...MOVING ACROSS THE
RELATIVELY WARM LAKE SUPERIOR WATERS WILL LEAD TO PERSISTENT LAKE
EFFECT. AMOUNTS AND LOCATIONS WILL LARGELY DEPEND ON WIND DIRECTION
AND DEEPER MOISTURE DURING THIS PERIOD.
FOR WEDNESDAY NIGHT...LAKE EFFECT WILL BE INCREASING IN INTENSITY
OVER THE WEST THROUGH THE NIGHT DUE TO INCREASING COLD AIR AND
DEEPER MOISTURE ARRIVING FROM THE NORTHWEST. THIS WILL PUSH
INVERSION HEIGHTS TOWARDS 10KFT OVER THE WITH WESTERN AREAS AND
WITH DELTA-T VALUES AROUND 23...LAKE INDUCED CAPE VALUES RISE
TOWARDS 500-700 J/KG. EXPECT THE HIGHEST AMOUNTS...2-6 INCHES...IN
THE NORTH-NORTHWEST WIND FAVORED LOCATIONS. OVER THE
EAST...FORECAST IS A LITTLE MORE UNCERTAIN DUE TO THE SYSTEM...BUT
THEY TOO SHOULD TRANSITION TO LAKE EFFECT. WITH MOISTURE HELP FROM
THE SYSTEM...SNOW AMOUNTS WILL BE HIGHER THERE ESPECIALLY IN THE
LOCATIONS FAVORED BY NORTH-NORTHWEST WINDS. THE HIGHEST AMOUNTS WILL
LIKELY OCCUR THROUGH THE NIGHT OVER THE WESTERN PORTIONS OF ALGER
COUNTY...WHERE COASTAL EFFECTS FROM NORTHERN MARQUETTE COUNTY WILL
LIKELY INCREASE CONVERGENCE THERE AND THUS SNOWFALL AMOUNTS. HAVE
TRENDED POPS TOWARDS THIS IDEA FOR THE WEDNESDAY NIGHT PERIOD.
WITH THE COLD AIR CONTINING TO FLOW OVER THE AREA ON
THURSDAY...MULTI-BAND LAKE EFFECT WILL BE AIDED BY THE INCREASED MID
LEVEL MOISTURE MOVING OVER THE AREA BEHIND A SHORTWAVE DROPPING
THROUGH THE UPPER/MID MISSISSIPPI VALLEY ON THURSDAY. THIS WILL LEAD
TO INVERSION HEIGHTS IN THE 7-10KFT RANGE OVER THE AREA...WITH THE
HIGHEST VALUES OVER THE EAST. THE MAIN DETERMINING FACTOR FOR SNOW
AMOUNTS IN THE NORTHWEST WIND FAVORED LOCATIONS ON THURSDAY WILL BE
WHEN THE DGZ FALLS BELOW OR TO THE BOTTOM OF THE CLOUD LAYER. THIS
WILL OCCUR FIRST OVER THE WEST AND THEN OVER THE EAST LATE IN THE
DAY. THIS WILL LEAD TO A TRANSITION TO LOWER SNOW RATIOS WITH THE
TRANSITION TO MORE COLUMNS THAT IS USUALLY SEEN IN COLD/ARCTIC AIR
MASSES. WITH THE WINDS BACKING TO MORE OF A NORTHWEST WIND
DIRECTION THROUGH DAY...WOULD EXPECT THERE TO BE A COUPLE ENHANCED
LOCATIONS DUE TO INCREASED CONVERGENCE. AT THIS TIME...WOULD EXPECT
IT TO BE OVER GOGEBIC/ONTONAGON AND ALGER COUNTIES.
HIGH PRESSURE SLIDING SOUTHEAST FROM THE DAKOTAS ON THURSDAY NIGHT
WILL LEAD TO BACKING WINDS TO THE WEST OVER THE WESTERN LAKE AND
WEST-NORTHWEST OVER THE EAST. THIS WILL CONTINUE INTO FRIDAY AS THE
HIGH MOVES INTO THE MID MISSISSIPPI VALLEY AND LEADS TO WEST TO
WEST-SOUTHWEST WINDS. THESE WINDS WILL BE AIDED BY A WEAK LOW
DEVELOPING OVER EASTERN LAKE SUPERIOR. COLD AIR IS STILL IN THE
LOWER -20S CELSIUS DURING THE PERIOD...SO THE LAKE EFFECT WILL BE
ONGOING. BUT...WITH THE HIGH REDUCING THE MOISTURE ABOVE H850 AND
INCREASING THE SUBSIDENCE INVERSION EXPECT THERE TO BE A GRADUAL
DECREASE IN INTENSITY DURING THAT TIME FRAME.
DEFINITELY THINK THAT THE NORTH-NORTHWEST WIND LOCATIONS WILL NEED
LAKE EFFECT SNOW ADVISORIES DURING THIS WEDNESDAY NIGHT INTO
THURSDAY NIGHT PERIOD. WARNINGS ARE A LITTLE MORE UNCERTAIN DUE TO
THE LIMITED PERIODS OF THE BEST OMEGA WITHIN THE DGZ. OUT OF ALL OF
THE LOCATIONS...WOULD THINK THAT ALGER COUNTY WOULD HAVE THE BEST
OPPORTUNITY OF SEEING WARNING SNOWFALL AMOUNTS. OPTED TO GO AHEAD
AND ISSUE THE LAKE EFFECT SNOW ADVISORY FOR GOGEBIC/ONTONAGON
COUNTIES AND THE REST OF THE FAVORED AREAS WILL NEEDED TO BE ADDED
IN THE NEXT 12-24HRS.
HEADING INTO THE WEEKEND...THE COLDER AIR WILL BEGIN TO LOSE IT/S
GRIP ON THE AREA AS THE UPPER TROUGH SHIFTS TO THE EAST AND AREA
COMES UNDER NORTHWEST FLOW ALOFT. THESE PERIODS COME DOWN TO
TIMING/LOCATING SHORTWAVES MOVING THROUGH THE FLOW AND HAVE TRIED
TO FOLLOW A GENERAL CONSENSUS FOR TIMING THESE WAVES. FIRST ONE
LOOKS TO MOVE THROUGH THE AREA ON SATURDAY NIGHT AND AGAIN ON
SUNDAY NIGHT INTO MONDAY. BETWEEN THOSE TWO PERIODS...THERE SHOULD
BE ENOUGH COLD AIR TO SUPPORT LAKE EFFECT SNOW IN AREAS FAVORED BY
NORTHWEST WINDS.
WITH THE COLD AIR SPILLING INTO THE AREA...A COOLING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WORK WEEK. FRIDAY CONTINUES TO
LOOK LIKE THE COLDEST DAY OVER THE NEXT 7 DAYS...WITH HIGHS OVER THE
WEST STRUGGLING TO RISE ABOVE 0 DEGREES. THIS COLD AIR WILL CAUSE
WIND CHILL VALUES TO APPROACH -25 ON ON THURSDAY NIGHT INTO
FRIDAY MORNING AND AGAIN FRIDAY NIGHT INTO SATURDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. TEMPERATURES WILL THEN WARM
BACK TO MORE NORMAL VALUES BY THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 551 PM EST TUE JAN 29 2013
IFR/LOW MVFR CIGS WILL PERSIST AT IWD AND CMX OVERNIGHT. LIFR CIGS
WILL REMAIN AT SAW OVERNIGHT AS NRLY UPSLOPE WINDS CONTINUE. LIGHT
SNOW WILL SPREAD INTO MAINLY CNTRL AND EAST UPPER MI WED MORNING
WITH IFR VSBY EXPECTED AT SAW. SOME LAKE ENHANCED SNOW AT IWD SHOULD
ALSO LEAD TO IFR CONDITIONS WHILE CMX IS EXPECTED TO ONLY SEE MVFR
CIGS/VSBY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 PM EST TUE JAN 29 2013
A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH LAKE HURON WEDNESDAY
AND TO THE NORTHEAST BY WEDNESDAY NIGHT WILL LIKELY BRING A PERIOD
OF N TO NW GALES TO CENTRAL AND EASTERN LAKE SUPERIOR LATE TONIGHT
INTO WEDNESDAY NIGHT. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING
OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT
TIMES LATE WEDNESDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 PM CST WEDNESDAY FOR
MIZ011.
WINTER STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 10 PM EST
/9 PM CST/ WEDNESDAY FOR MIZ012>014.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM EST /6 AM CST/ WEDNESDAY TO
7 AM EST /6 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM WEDNESDAY TO 7 AM EST
FRIDAY FOR LSZ265>267.
GALE WARNING FROM 10 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ267.
GALE WARNING FROM 5 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ WEDNESDAY
TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263-264.
GALE WARNING FROM 5 AM TO 10 PM EST WEDNESDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 PM EST TUE JAN 29 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 504 PM EST TUE JAN 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS INTO NEW MEXICO. WEAK SHRTWVS
EMBEDDED IN THE SW FLOW FROM THE SRN PLAINS INTO THE GREAT LAKES
SUPPORTED AREAS OF SHRA/TSRA NEAR A SFC FRONT EXTENDING FROM NE WI
THROUGH CNTRL MO AND INTO CNTRL OK. THE MAIN SHRTWV WAS REMAINED
NEAR THE BASE OF THE TROUGH...MOVING TOWARD THE TX/OK PANHANDLE.
PCPN HAD DIMINISHED OVER UPPER MICHIGAN WITH MAINLY SOME SCT LIGHT
SHOWERS MOVING THROUGH FAR SRN UPPER MI. WEST WINDS AND SLIGHTLY
DRIER AIR BEHIND A TROUGH SLIDING TO NEAR P53-ISQ HAS BROUGHT
IMPROVED VISIBILITIES THROUGH THE CNTRL AND WEST CWA.
ALTHOUGH THE 12Z ECMWF WAS A BIT SLOWER THAN THE 12Z GFS...THE MODELS
WERE IN RELATIVELY GOOD AGREEMENT WITH REGARD TO OVERALL PCPN/SNOW
POTENTIAL ACROSS THE CWA. ALTHOUGH THE 12Z NAM HAD SHIFTED THE
HEAVIER QPF AXIS WELL TO THE EAST...THE 18Z RUN HAS COME BACK INTO
BETTER AGREEMENT WITH THE GLOBAL MODELS. MODELS DIFFICULTY IN
HANDLING THE CONVECTION AND HEAVY RAIN NEAR THE FRONT MAY ACCOUNT
FOR A PORTION OF THE INCONSISTENCY AND VARIABILITY AND STILL LEADS
GREATER THAN USUAL UNCERTAINTY. ALTHOUGH THERE IS MODERATE
CONFIDENCE WITH THE MULTI-MODEL BLEND OF THE GFS/ECMWF/NAM/REG-GEM
USED FOR QPF...TIMING OF THE HEAVIER PCPN ONSET MAY BE A BIT DELAYED
GIVEN ECMWF/NAM TRENDS.
THE STRONGEST DYNAMICS ARE EXPECTED TO DEVELOP BTWN 12Z-18Z/WED AS
THE NM SHRTWV LIFTS TOWARD THE GREAT LAKES. A COUPLED UPPER LEVEL
JET STRUCTURE AND RESULTING STRONG 800-600 MB FGEN WILL SUPPORT A
PERIOD OF MODERATE TO HEAVY PCPN IN THE REGION...WITH THE BEST
CHANCE FOR HEAVY SNOW OVER THE SE HALF OF UPPER MI. EXPECT A SHARP
NW EDGE OF THE PCPN BAND DUE TO STRONG DESCENDING FGEN CIRCULATION
BRANCH WHICH REDUCES CONFIDENCE IN PCPN AMOUNTS THROUGH CNTRL UPPER
MI. QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE WITH SNOW/WATER RATIO
VALUES NEAR 16/1 SUPPORTS GENERALLY 4 TO 8 INCH SYNOPTIC
SNOW...GREATEST OVER THE FAR S AND EAST. LAKE ENHANCED SNOW WILL
GENERALLY BE LIGHT EARLY WED WITH LOW INVERSION HEIGHTS NEAR 4K FT
AND 850 MB TEMPS ONLY NEAR -10C BUT BY WED AFTERNOON SNOWFALL RATES
OVER N CNTRL AND FAR WEST NEAR IWD SHOULD INCREASE AS 850 MB TEMPS
FALL TO NEAR -16C. ALTHOUGH UPSLOPE FLOW SHOULD ENHANCE SNOWFALL
RATES...CYCLONIC 350 FLOW MAY ALSO LEAD TO GREATER AMOUNTS NEAR THE
SHORE WED AFTERNOON.
FCST CONFIDENCE WAS HIGH ENOUGH TO UPGRADE WATCHES TO WARNINGS OVER
THE EAST HALF BUT WITH AMOUNTS ONLY IN THE 2 TO 5 INCH RANGE OVER
MARQUETTE AND DICKINSON COUNTIES THROUGH WED AND PROXIMITY TO THE
EDGE OF THE SYNOPTIC PCPN...AN ADVY WAS ISSUED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 29 2013
INITIAL PART OF THE LONG TERM FORECAST IS HIGHLY DEPENDENT ON THE
TRACK OF THE SHORTWAVE RIDING UP THE UPPER TROUGH OVER THE CENTRAL
CONUS AND THE ASSOCIATED LOW DEVELOPING IN NORTHERN LOWER MI AND
THEN SHIFTING NORTHEAST INTO QUEBEC ON WEDNESDAY NIGHT. THE SHORT
TERM DISCUSSION COVERS MUCH OF THE DETAILS WITH THIS SYSTEM AND THE
MAIN FEATURE TO CAPTURE IN THE LONG TERM WITH THIS SYSTEM IS THE
DIMINISHING TREND IN THE POPS/QPF OVER THE EASTERN CWA.
BEHIND THIS FEATURE...EXPECT COLD AIR TO SURGE SOUTHEAST OVER THE
UPPER GREAT LAKES REGION AND REMAIN INTO THE WEEKEND. THIS COLD
AIR...H850 TEMPS IN THE LOW -20S CELSIUS...MOVING ACROSS THE
RELATIVELY WARM LAKE SUPERIOR WATERS WILL LEAD TO PERSISTENT LAKE
EFFECT. AMOUNTS AND LOCATIONS WILL LARGELY DEPEND ON WIND DIRECTION
AND DEEPER MOISTURE DURING THIS PERIOD.
FOR WEDNESDAY NIGHT...LAKE EFFECT WILL BE INCREASING IN INTENSITY
OVER THE WEST THROUGH THE NIGHT DUE TO INCREASING COLD AIR AND
DEEPER MOISTURE ARRIVING FROM THE NORTHWEST. THIS WILL PUSH
INVERSION HEIGHTS TOWARDS 10KFT OVER THE WITH WESTERN AREAS AND
WITH DELTA-T VALUES AROUND 23...LAKE INDUCED CAPE VALUES RISE
TOWARDS 500-700 J/KG. EXPECT THE HIGHEST AMOUNTS...2-6 INCHES...IN
THE NORTH-NORTHWEST WIND FAVORED LOCATIONS. OVER THE
EAST...FORECAST IS A LITTLE MORE UNCERTAIN DUE TO THE SYSTEM...BUT
THEY TOO SHOULD TRANSITION TO LAKE EFFECT. WITH MOISTURE HELP FROM
THE SYSTEM...SNOW AMOUNTS WILL BE HIGHER THERE ESPECIALLY IN THE
LOCATIONS FAVORED BY NORTH-NORTHWEST WINDS. THE HIGHEST AMOUNTS WILL
LIKELY OCCUR THROUGH THE NIGHT OVER THE WESTERN PORTIONS OF ALGER
COUNTY...WHERE COASTAL EFFECTS FROM NORTHERN MARQUETTE COUNTY WILL
LIKELY INCREASE CONVERGENCE THERE AND THUS SNOWFALL AMOUNTS. HAVE
TRENDED POPS TOWARDS THIS IDEA FOR THE WEDNESDAY NIGHT PERIOD.
WITH THE COLD AIR CONTINING TO FLOW OVER THE AREA ON
THURSDAY...MULTI-BAND LAKE EFFECT WILL BE AIDED BY THE INCREASED MID
LEVEL MOISTURE MOVING OVER THE AREA BEHIND A SHORTWAVE DROPPING
THROUGH THE UPPER/MID MISSISSIPPI VALLEY ON THURSDAY. THIS WILL LEAD
TO INVERSION HEIGHTS IN THE 7-10KFT RANGE OVER THE AREA...WITH THE
HIGHEST VALUES OVER THE EAST. THE MAIN DETERMINING FACTOR FOR SNOW
AMOUNTS IN THE NORTHWEST WIND FAVORED LOCATIONS ON THURSDAY WILL BE
WHEN THE DGZ FALLS BELOW OR TO THE BOTTOM OF THE CLOUD LAYER. THIS
WILL OCCUR FIRST OVER THE WEST AND THEN OVER THE EAST LATE IN THE
DAY. THIS WILL LEAD TO A TRANSITION TO LOWER SNOW RATIOS WITH THE
TRANSITION TO MORE COLUMNS THAT IS USUALLY SEEN IN COLD/ARCTIC AIR
MASSES. WITH THE WINDS BACKING TO MORE OF A NORTHWEST WIND
DIRECTION THROUGH DAY...WOULD EXPECT THERE TO BE A COUPLE ENHANCED
LOCATIONS DUE TO INCREASED CONVERGENCE. AT THIS TIME...WOULD EXPECT
IT TO BE OVER GOGEBIC/ONTONAGON AND ALGER COUNTIES.
HIGH PRESSURE SLIDING SOUTHEAST FROM THE DAKOTAS ON THURSDAY NIGHT
WILL LEAD TO BACKING WINDS TO THE WEST OVER THE WESTERN LAKE AND
WEST-NORTHWEST OVER THE EAST. THIS WILL CONTINUE INTO FRIDAY AS THE
HIGH MOVES INTO THE MID MISSISSIPPI VALLEY AND LEADS TO WEST TO
WEST-SOUTHWEST WINDS. THESE WINDS WILL BE AIDED BY A WEAK LOW
DEVELOPING OVER EASTERN LAKE SUPERIOR. COLD AIR IS STILL IN THE
LOWER -20S CELSIUS DURING THE PERIOD...SO THE LAKE EFFECT WILL BE
ONGOING. BUT...WITH THE HIGH REDUCING THE MOISTURE ABOVE H850 AND
INCREASING THE SUBSIDENCE INVERSION EXPECT THERE TO BE A GRADUAL
DECREASE IN INTENSITY DURING THAT TIME FRAME.
DEFINITELY THINK THAT THE NORTH-NORTHWEST WIND LOCATIONS WILL NEED
LAKE EFFECT SNOW ADVISORIES DURING THIS WEDNESDAY NIGHT INTO
THURSDAY NIGHT PERIOD. WARNINGS ARE A LITTLE MORE UNCERTAIN DUE TO
THE LIMITED PERIODS OF THE BEST OMEGA WITHIN THE DGZ. OUT OF ALL OF
THE LOCATIONS...WOULD THINK THAT ALGER COUNTY WOULD HAVE THE BEST
OPPORTUNITY OF SEEING WARNING SNOWFALL AMOUNTS. OPTED TO GO AHEAD
AND ISSUE THE LAKE EFFECT SNOW ADVISORY FOR GOGEBIC/ONTONAGON
COUNTIES AND THE REST OF THE FAVORED AREAS WILL NEEDED TO BE ADDED
IN THE NEXT 12-24HRS.
HEADING INTO THE WEEKEND...THE COLDER AIR WILL BEGIN TO LOSE IT/S
GRIP ON THE AREA AS THE UPPER TROUGH SHIFTS TO THE EAST AND AREA
COMES UNDER NORTHWEST FLOW ALOFT. THESE PERIODS COME DOWN TO
TIMING/LOCATING SHORTWAVES MOVING THROUGH THE FLOW AND HAVE TRIED
TO FOLLOW A GENERAL CONSENSUS FOR TIMING THESE WAVES. FIRST ONE
LOOKS TO MOVE THROUGH THE AREA ON SATURDAY NIGHT AND AGAIN ON
SUNDAY NIGHT INTO MONDAY. BETWEEN THOSE TWO PERIODS...THERE SHOULD
BE ENOUGH COLD AIR TO SUPPORT LAKE EFFECT SNOW IN AREAS FAVORED BY
NORTHWEST WINDS.
WITH THE COLD AIR SPILLING INTO THE AREA...A COOLING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WORK WEEK. FRIDAY CONTINUES TO
LOOK LIKE THE COLDEST DAY OVER THE NEXT 7 DAYS...WITH HIGHS OVER THE
WEST STRUGGLING TO RISE ABOVE 0 DEGREES. THIS COLD AIR WILL CAUSE
WIND CHILL VALUES TO APPROACH -25 ON ON THURSDAY NIGHT INTO
FRIDAY MORNING AND AGAIN FRIDAY NIGHT INTO SATURDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. TEMPERATURES WILL THEN WARM
BACK TO MORE NORMAL VALUES BY THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 139 PM EST TUE JAN 29 2013
MAINLY IFR CIGS ARE EXPECTED TO PERSIST AT CMX/IWD THIS AFTERNOON.
AS WINDS VEER WEST BEHIND A TROUGH THIS AFTERNOON VSBY IS EXPECTED
TO IMPROVE AT SAW EVEN THOUGH IFR CIGS WILL PERSIST. LIGHT SNOW WILL
SPREAD INTO MAINLY CNTRL AND EAST UPPER MI WED MORNING WITH IFR VSBY
EXPECTED AT SAW. SOME LAKE ENHANCED SNOW AT IWD SHOULD ALSO LEAD TO
IFR CONDITIONS WHILE CMX IS EXPECTED TO ONLY SEE MVFR CIGS/VSBY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 PM EST TUE JAN 29 2013
A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH LAKE HURON WEDNESDAY
AND TO THE NORTHEAST BY WEDNESDAY NIGHT WILL LIKELY BRING A PERIOD
OF N TO NW GALES TO CENTRAL AND EASTERN LAKE SUPERIOR LATE TONIGHT
INTO WEDNESDAY NIGHT. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING
OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT
TIMES LATE WEDNESDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 PM CST WEDNESDAY FOR
MIZ011.
WINTER STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 10 PM EST
/9 PM CST/ WEDNESDAY FOR MIZ012>014.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM EST /6 AM CST/ WEDNESDAY TO
7 AM EST /6 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM WEDNESDAY TO 7 AM EST
FRIDAY FOR LSZ265>267.
GALE WARNING FROM 10 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ267.
GALE WARNING FROM 5 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ WEDNESDAY
TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263-264.
GALE WARNING FROM 5 AM TO 10 PM EST WEDNESDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
349 PM EST TUE JAN 29 2013
.SYNOPSIS...
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF FOG WILL GIVE WAY TO HEAVY RAIN TONIGHT AS LOW PRESSURE
MOVES THROUGH. SOME FLOODING IS POSSIBLE. THE RAIN WILL MOVE EAST
ON WEDNESDAY WITH COLDER AIR MOVING IN ALONG WITH SOME RAIN
CHANGING TO SNOW. TEMPERATURES WILL CONTINUE TO FALL THROUGH
FRIDAY ALONG WITH LAKE EFFECT SNOW SHOWERS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF PATCHY DENSE FOG WILL CONTINUE THIS EVENING ACROSS THE
NORTHERN ZONES UNTIL THE WARM FRONT LIFTS THROUGH. COVERAGE IS
VARIABLE ENOUGH TO NOT GO WITH A DENSE FOG ADVISORY BUT WILL HAVE
TO MONITOR OBS NEXT FEW HOURS.
FLOOD WATCH CONTINUES TONIGHT FOR ALL ZONES. MOST IF NOT ALL OF
THE SNOW IS GONE ACROSS THE CENTRAL AND SOUTHERN ZONES BUT SOME
SNOWMELT CONTRIBUTION REMAINS UP NORTH WHERE QPF IS EXPECTED TO BE
1 TO 2 INCHES. 12Z MODEL GUIDANCE SHIFTED NORTH WITH THE AXIS OF
HEAVIEST QPF ALTHOUGH THE HRRR HAS BEEN SHOWING THE MOST
CONVECTIVE...AND HEAVIER...RAINS FURTHER SOUTH AND EAST. SEE HYDRO
SECTION OF FORECAST FOR SPECIFICS ON RIVER FLOOD WARNINGS.
EXPECT THE HEAVIEST RAINS TO MOVE INTO WESTERN ZONES THIS EVENING
THEN MARCH STEADILY ACROSS THE FORECAST AREA OVERNIGHT...DEPARTING
THE EASTERN ZONES WEDNESDAY MORNING. THE DEFORMATION RAIN/SNOW
ZONE SHOULD BE REACHING THE NORTHWEST FORECAST AREA WEDNESDAY
MORNING. WILL HAVE TO WATCH THIS AREA FOR ACCUMULATING SNOW BY LATE
WEDNESDAY MORNING INTO THE AFTERNOON. COLD AIR ARRIVES IN THE
AFTERNOON WITH LAKE EFFECT KICKING IN WEDNESDAY NIGHT. EXPECT LAKE
EFFECT TO PENETRATE INLAND THURSDAY AND THURSDAY NIGHT WITH FLOW
GOING NORTHWEST TO WEST.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 348 PM EST TUE JAN 29 2013
THE ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT THROUGH THE WEEKEND.
BOTH MODELS SHOW THE DEEP UPPER TROUGH MOVING EAST AWAY FROM THE
AREA AND TAKING THE CORE OF THE COLD AIR WITH IT. THE DGZ IS ALREADY
GOING TO BE VERY LOW FRIDAY AND WITH THE COLD AIR MOVING AWAY WE/LL
SEE THE EASTERN EDGE OF THE LAKE EFFECT SNOW SHOWERS RETREATING
TOWARD THE LAKE SHORE AND THEN DIMINISHING FRIDAY NIGHT AND
SATURDAY.
THE NEXT CHC FOR SNOW AFTER THAT WILL BE MONDAY WHEN A CLIPPER
MOVES TOWARD NRN LWR. THE GFS TAKES A MORE SRN TRACK AND WOULD
GIVE US MORE SNOW. HOWEVER...WE HAVE NOT HAD MANY CLIPPERS THAT
HAVE CROSSED THE CWA THIS YEAR AND SO WE/LL LEAN MORE TOWARD THE
FARTHER NORTH ECMWF. TEMPS WILL WARM FROM HIGHS IN THE MID TEENS
FRIDAY TO MID 30S BY MONDAY BEFORE COOLING OFF TUESDAY AFTER THE
CLIPPER DRAGS A COLD FRONT THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1252 PM EST TUE JAN 29 2013
WIDESPREAD IFR/LIFR CONDITIONS EXPECTED THROUGH THE PERIOD. WE/LL
SEE CONSIDERABLE RAIN TONIGHT AHEAD OF THE ARCTIC FRONT. TSRA ALSO
EXPECTED FROM AROUND SUNSET THROUGH MUCH OF THE OVERNIGHT HOURS.
IT/S POSSIBLE THAT SNOW WILL MIX IN WITH THE RAIN AT KMKG MID TO
LATE MORNING WEDNESDAY.
&&
.MARINE...
ISSUED AT 348 PM EST TUE JAN 29 2013
WILL HOIST A SMALL CRAFT ADVISORY FOR TONIGHT THROUGH THURSDAY
MORNING. THIS MAY HAVE TO BE UPGRADED TO A GALE WARNING FOR
WEDNESDAY LATER ON...BUT FOR NOW IT APPEARED MARGINAL ENOUGH TO
JUST GO WITH A SCA THROUGH THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 348 PM EST TUE JAN 29 2013
SCOTTVILLE ON THE PERE MARQUETTE IS FORECAST TO FLOOD...BUT OTHER
RIVER POINTS ARE CURRENTLY EXPECTED TO STAY BELOW FLOOD STAGE.
WILL HAVE TO WATCH THE PROGRESSION OF RAIN AND SNOW MELT THIS
EVENING AND SOME OTHER SITES MAY BE ADDED TO FLOOD WARNINGS AT
SOME POINT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH WEDNESDAY
AFTERNOON FOR MIZ037>040-043>046-050>052-056>059-064>067-
071>074.
LM...SMALL CRAFT ADVISORY FROM 1 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...93
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS HASTINGS NE
358 PM CST TUE JAN 29 2013
.SHORT TERM...TONIGHT AND WEDNESDAY.
HIGHLY AMPLIFIED MEAN TROUGH IS HEADING EAST WITH THE AXIS CROSSING
INTO THE HIGH PLAINS. STRONG JET AHEAD OF THIS AXIS WITH STIFF
MID-LEVEL FRONTOGENETIC FORCING PREDICTED TO RAMP UP THIS EVENING.
THIS IS SUPPORTED BY THE NAM...HRRR...ECMWF...AND GFS...ALL PLACING
DECENT QPF AMOUNTS IN THE EAST/SOUTHEAST PART OF THE CWA AT THE VERY
LEAST.
THIS AGREEMENT AMONG MODELS HAS LED ME TO INCREASE CHANCES OF
PRECIPITATION EVEN MORE. SOUNDINGS INDICATE THAT THIS WILL BE A SNOW
EVENT AND HAVE GONE WITH ONLY SNOW AS THE PRECIPITATION TYPE...AS
OPPOSED TO MENTIONING RAIN AT ONSET. THE HRRR INDICATE4D QUITE A RAMP
UP IN QPF PRODUCTION BY EARLY AFTERNOON...WHICH PROMPTED ME TO GO
WITH AN ADVISORY FOR MOST OF OUR EASTERN CWA. I FELT INCLINED TO DO
THIS AS NORTH/NORTHWEST WIND WILL RAMP UP CONSIDERABLY TONIGHT AS
THE SURFACE PRESSURE GRADIENT INCREASES. I INCREASED WIND SPEEDS A
BIT MORE FROM THE PREVIOUS FORECAST FOR TONIGHT INTO WEDNESDAY. SNOW
SHOULD WIND DOWN FAIRLY QUICKLY AS THE TROUGH AXIS HEADS TO THE EAST
BY THE OVERNIGHT. LEFT THE SLIGHT CHANCE OF FLURRIES IN OUR
NORTHEAST FOR WEDNESDAY MORNING...BUT I DID NOTICE THE NAM PULLING
BACK A LITTLE ON STRATUS...WHICH USUALLY INDICATES A LACK OF FLURRY
POTENTIAL...BUT CLOSE ENOUGH FOR ME TO LEAVE IN FOR NOW. WIND SHOULD
REMAIN BELOW WIND ADVISORY CRITERIA FOR WEDNESDAY...ALTHOUGH OUR FAR
NORTH MAY FLIRT WITH IT...JUDGING BY PREDICTED MOMENTUM TRANSFER.
KEPT SKY COVER GENERALLY CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS...ESPECIALLY IN THE SOUTH BY AFTERNOON. KEPT TEMPERATURES THE
SAME FOR TONIGHT AND WEDNESDAY FROM PREVIOUS FORECAST AS THEY LOOKED
LIKE THEY WERE RIGHT ON TARGET.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. MAIN FORECAST CONCERN
IN THE EXTENDED WILL BE THE TEMPERATURES.
STARTING WED EVENING...THE BIG PICTURE SHOWS THE CENTRAL U.S. IN
NORTHWEST FLOW AS THE UPPER TROUGH IS SLATED TO BE MOVING INTO THE
MIDWEST WITH RIDGING MOVING ONTO THE PACIFIC NORTHWEST COAST. AS THE
WORK WEEK ROLLS ALONG IT APPEARS WE WILL PRETTY MUCH STAY IN THIS
TYPE OF FLOW WITH OVERALL RIDGING TO THE WEST AND TROUGHING EAST.
WILL MOST LIKELY HAVE A FEW CLIPPER LIKE WAVES SLIDE THROUGH OUR
REGION UNDER THIS TYPE OF PATTERN AND THE QUESTION IS WILL THEY
BRING ANY ADDITIONAL PRECIPITATION CHANCES. BASIC ANSWER IS NO
ALTHOUGH WE DO HAVE A CHANCE OF FLURRIES MENTIONED FOR WED NIGHT AND
THURSDAY IN THE CURRENT FORECAST AND WILL GO AHEAD AND KEEP THEM IN
GIVEN SUFFICIENT MOISTURE AND COLDER TEMPERATURES NOTED IN MODEL
FORECAST SOUNDINGS. OTHERWISE WILL LEAVE THE REST OF THE FORECAST
DRY ALTHOUGH SOME LIGHT PRECIPITATION NOT TOTALLY OUT OF THE
QUESTION FOR FRIDAY.
AS FAR AS TEMPERATURES GO...IT WILL REMAIN QUITE CHILLY WED NIGHT
INTO FRIDAY MORNING AS ADDITIONAL COLD AIR SLIDES DOWN FROM THE
NORTH...ALTHOUGH THE BITTER COLD AIR SHOULD REMAIN JUST NORTHEAST OF
THE CWA. STOUT NORTHWEST WINDS ARE ALSO EXPECTED AGAIN FOR THURSDAY
AFTERNOON AS WE SIT BETWEEN 1038 MB HIGH PRESSURE OVER MONTANA/NDAK
AND LOW PRESSURE ACROSS MISSOURI AND KANSAS. FRIDAY MORNING MIGHT
BE THE COLDEST DAY OF THE WEEK DEPENDING ON WHETHER HIGH PRESSURE
DROPS RIGHT OVER THE TOP OF US OR SLIDES A LITTLE TO THE EAST IN
WHICH CASE WE MIGHT HAVE A MORE CLOUD COVER AND LIGHT SOUTHERLY
FLOW.
GOING INTO THE WEEKEND HEIGHTS BEGIN TO RISE AS WESTERN RIDGE STARTS
TO MOVE EAST AND AT THIS POINT APPEARS BOTH SAT AND SUNDAY SHOULD BE
CLOSE TO 50 DEGREES. ANOTHER WEAK FRONT IS EXPECTED TO PUSH ACROSS
SUNDAY NIGHT OR MONDAY WITH HIGH TEMPERATURES FALLING A TAD BUT
STILL ABOVE SEASONAL LEVELS.
&&
.PREV DISCUSSION... /ISSUED 1243 PM CST TUE JAN 29 2013/
AVIATION...18Z KGRI TAF. CEILINGS WILL BE TRICKY FOR THE FIRST
SEVERAL HOURS OF THE FORECAST AS CEILINGS ARE HIGHLY VARIABLE EAST
OF A BAND OF SNOW THAT HAS DEVELOPED WEST OF THE TERMINAL. SOME
SNOW IS EXPECTED TO MOVE IN THIS EVENING WITH AN INCREASE IN WIND
SPEED BEHIND A COLD FRONT. MVFR CEILINGS ARE FORECAST FOR MUCH OF
THE FORECAST. VISIBILITY IS FORECAST FOR MVFR WHEN SNOW
BEGINS...BUT THIS COULD BE TEMPORARILY LOWER IF A BAND OF HEAVIER
SNOW SETS UP...BUT THIS IS MORE LIKELY TO OCCUR TO THE SOUTHEAST.
CEILINGS SHOULD RISE TOWARD MID-MORNING WEDNESDAY...BUT WIND WILL
REMAIN RATHER BRISK FROM THE NORTHWEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 1 AM CST WEDNESDAY FOR NEZ049-063-
064-076-077-086-087.
KS...WINTER WEATHER ADVISORY UNTIL 1 AM CST WEDNESDAY FOR KSZ007.
&&
$$
SHORT TERM/AVIATION...HEINLEIN
LONG TERM...EWALD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1059 AM CST TUE JAN 29 2013
.DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
&&
.AVIATION...
PACIFIC FRONT EXTENDED EAST OF AN OZONA...SAN ANGELO...ABILENE...
THROCKMORTON LINE AT 11 AM...MOVING EAST. WEST WINDS WILL INCREASE
RAPIDLY EARLY THIS AFTERNOON...WITH GUSTS OF 40 KTS AT KSJT AND KABI.
WINDS SHOULD DECREASE AFTER 0Z...OR 6 PM. AN ISOLATED THUNDERSTORM
POSSIBLE AT KBBD...KSOA...AND KJCT THIS AFTERNOON. BEST POTENTIAL
WILL BE A KBBD WHERE I WILL INCLUDE A VCTS. VISIBILITIES MAY FALL
SLIGHTLY IN BLOWING DUST LATE THIS AFTERNOON OR EARLY
EVENING...BUT EXPECT THEM TO REMAIN ABOVE 5 SM.
&&
.PREV DISCUSSION... /ISSUED 1000 AM CST TUE JAN 29 2013/
UPDATE...
UPATED TO ADD MORNING THUNDERSTORM FARTHER WEST. INCREASED
TEMPERATURES AND DEW POINTS.
DISCUSSION...
DRYLINE AND SURFACE TROUGH WERE FARTHER WEST THIS MORNING WITH MID
LEVEL CLOUDS PREVENTING MIXING. THUNDERSTORMS WERE DEVELOPING
BETWEEN OZONA AND MERTZON ALONG THE TROUGH. POTENTIAL EXISTS FOR A
STRONG..POSSIBLY EVEN A SEVERE STORM AS THE SURFACE TROUGH MOVES
EAST THROUGH EARLY AFTERNOON...MAINLY ALONG AND EAST AF A SAN ANGELO TO
ABILENE TO THROCKMORTON LINE WITH RUC SFC BASE CAPES OF 1500 TO
1900 J/KG.
04
PREV DISCUSSION... /ISSUED 516 AM CST TUE JAN 29 2013/
AVIATION...
/12Z UPDATE/
VFR CONDITIONS WILL CONTINUE OVER THE NORTHERN TERMINALS THROUGH
THE TAF PERIOD. MVFR CEILINGS OVER THE SOUTHERN TERMINALS WILL
LIFT TO VFR BY NOON...REMAINING VFR FOR THE REMAINDER OF THE TAF
PERIOD. A COLD FRONT WILL MOVE QUICKLY EAST THROUGH THE AREA THIS
MORNING BRINGING HIGH WINDS TO THE TERMINALS. SURFACE WINDS WILL
CONTINUE TO INCREASE IN SPEED THROUGH THE DAY. KABI CAN EXPECT
WESTERLY GUSTS TO OVER 30KT FOR MOST OF THE DAY WITH GUSTS AS HIGH
AS 45KT BY NOON. WINDS AT KSJT WILL GUST TO AROUND 35KT BY NOON.
FOR THE SOUTHERN TERMINALS EXPECT WIND GUSTS FROM 25KT TO 35KT BY
NOON. WINDS WILL DECREASE TO LESS THAN 20KT BY THIS EVENING AT ALL
TERMINALS. BLDU WILL REDUCE VISIBILITIES AT THE NORTHERN
TERMINALS BY NOON TO AROUND 6SM.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 34 56 31 68 / 20 5 0 0 0
SAN ANGELO 70 36 56 27 68 / 20 0 0 0 0
JUNCTION 72 35 59 26 68 / 20 5 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 7 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...
COLEMAN...CONCHO...CROCKETT...FISHER...HASKELL...IRION...JONES...
KIMBLE...MENARD...NOLAN...RUNNELS...SCHLEICHER...SHACKELFORD...
STERLING...SUTTON...TAYLOR...THROCKMORTON...TOM GREEN.
WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO...CROCKETT...
FISHER...HASKELL...IRION...JONES...MCCULLOCH...NOLAN...RUNNELS...
SHACKELFORD...STERLING...TAYLOR...THROCKMORTON...TOM GREEN.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1000 AM CST TUE JAN 29 2013
.UPDATE...
UPATED TO ADD MORNING THUNDERSTORM FARTHER WEST. INCREASED
TEMPERATURES AND DEW POINTS.
&&
.DISCUSSION...
DRYLINE AND SURFACE TROUGH WERE FARTHER WEST THIS MORNING WITH MID
LEVEL CLOUDS PREVENTING MIXING. THUNDERSTORMS WERE DEVELOPING
BETWEEN OZONA AND MERTZON ALONG THE TROUGH. POTENTIAL EXISTS FOR A
STRONG..POSSIBLY EVEN A SEVERE STORM AS THE SURFACE TROUGH MOVES
EAST THROUGH EARLY AFTERNOON...MAINLY ALONG AND EAST AF A SAN ANGELO TO
ABILENE TO THROCKMORTON LINE WITH RUC SFC BASE CAPES OF 1500 TO
1900 J/KG.
04
&&
.PREV DISCUSSION... /ISSUED 516 AM CST TUE JAN 29 2013/
AVIATION...
/12Z UPDATE/
VFR CONDITIONS WILL CONTINUE OVER THE NORTHERN TERMINALS THROUGH
THE TAF PERIOD. MVFR CEILINGS OVER THE SOUTHERN TERMINALS WILL
LIFT TO VFR BY NOON...REMAINING VFR FOR THE REMAINDER OF THE TAF
PERIOD. A COLD FRONT WILL MOVE QUICKLY EAST THROUGH THE AREA THIS
MORNING BRINGING HIGH WINDS TO THE TERMINALS. SURFACE WINDS WILL
CONTINUE TO INCREASE IN SPEED THROUGH THE DAY. KABI CAN EXPECT
WESTERLY GUSTS TO OVER 30KT FOR MOST OF THE DAY WITH GUSTS AS HIGH
AS 45KT BY NOON. WINDS AT KSJT WILL GUST TO AROUND 35KT BY NOON.
FOR THE SOUTHERN TERMINALS EXPECT WIND GUSTS FROM 25KT TO 35KT BY
NOON. WINDS WILL DECREASE TO LESS THAN 20KT BY THIS EVENING AT ALL
TERMINALS. BLDU WILL REDUCE VISIBILITIES AT THE NORTHERN
TERMINALS BY NOON TO AROUND 6SM.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 34 56 31 68 / 20 5 0 0 0
SAN ANGELO 70 36 56 27 68 / 20 0 0 0 0
JUNCTION 72 35 59 26 68 / 20 5 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 7 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...
COLEMAN...CONCHO...CROCKETT...FISHER...HASKELL...IRION...JONES...
KIMBLE...MENARD...NOLAN...RUNNELS...SCHLEICHER...SHACKELFORD...
STERLING...SUTTON...TAYLOR...THROCKMORTON...TOM GREEN.
WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO...CROCKETT...
FISHER...HASKELL...IRION...JONES...MCCULLOCH...NOLAN...RUNNELS...
SHACKELFORD...STERLING...TAYLOR...THROCKMORTON...TOM GREEN.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1023 AM PST Tue Jan 29 2013
.SYNOPSIS...
The weather pattern will remain active and wintry through Thursday
as a number of storm systems will result in periodic heavy snow
accumulations. There will be a break in the weather today...however
another extended snow event looks likely for the region with the
focus of the heavier snow again for the higher terrain of the
Central Idaho Panhandle...the Blue mountains and the Camas
Prairie. High pressure will build into the region at the end of
the work week and linger into the weekend with fog and low
stratus expected across much of the basin and in the valleys.
&&
.DISCUSSION...
rest of today...Looks like round two of the recent winter events
has generally wound down this morning. Radar no longer detecting
any precipitation over the Inland NW...while local webcams and
mesonet not detecting any either. Satellite was showing that much
of the mid and high level cloudiness has departed south and east
of the forecast area...with little upstream at this time. With a
dried out dendritic layer...there is little chance of additional
significant snow through the remainder of the day. Given current
trends and observations we have ended the winter weather
highlights for the Camas Prairie and Blue Mountains. Although both
locations could see some showers later today...additional
accumulations will be light. For the remainder of the forecast
area...the main changes revolved around lowering the sky cover
through the afternoon. The latest visible satellite imagery was
showing large holes in the high overcast...with the main cloud
cover now being attributed to low stratus across portions of NE
Washington and N Idaho. Clouds will increase once again late this
afternoon...as the next winter disturbance rounds the top of the
ridge and drops into the north Cascades via British Columbia. fx
&&
.AVIATION...
18Z TAFS: main trouble spots this morning are along the KGEG-KCOE
corridor due to areas of stratus and IFR cigs. Feel confident that
these should be mainly gone before 20-21z...with VFR conditions
after that. All remaining sites should be VFR through the daytime
hours. For tonight...the next winter system will come into play.
The latest HRRR has delayed the onset of the pcpn until aft 04z
for all sites xcp MWH and EAT. Feel confident that the pcpn will
be -sn for all sites xcp LWS and that IFR conditions will ensue
shortly after the onset of pcpn. Looks like the eastern sites
should see abt 6hrs of pcpn...aft which the main concern will be
widespread stratus and fog. MOS guidance is suggesting IFR
conditions for all the eastern sites and we have generally
followed suit. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 33 26 36 30 36 27 / 10 70 40 30 40 30
Coeur d`Alene 33 26 35 31 36 28 / 10 70 50 50 70 40
Pullman 36 27 39 33 39 30 / 10 70 70 70 60 50
Lewiston 43 32 44 37 46 32 / 10 70 70 70 60 40
Colville 34 25 35 30 41 26 / 10 60 20 20 30 30
Sandpoint 34 26 34 28 36 28 / 10 70 60 60 70 60
Kellogg 32 25 35 30 39 29 / 20 80 80 80 80 70
Moses Lake 39 28 41 29 41 27 / 0 10 10 10 10 10
Wenatchee 36 28 38 29 39 27 / 0 20 10 10 10 10
Omak 34 24 31 24 36 25 / 10 40 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$