Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/12/13
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1125 AM MST THU OCT 10 2013
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM WILL QUICKLY MOVE THROUGH THE AREA
TODAY...RESULTING IN SCATTERED SHOWERS THIS MORNING AND
SUBSTANTIALLY COOLER THAN NORMAL TEMPERATURES BY THIS AFTERNOON. DRY
CONDITIONS WITH A SLOW WARMING TREND IS EXPECTED TO BEGIN ON
FRIDAY...THEN CONTINUE INTO EARLY NEXT WEEK.
&&
.DISCUSSION...
THE UPPER LOW THAT HAS BROUGHT OUR CWA MUCH COOLER
TEMPERATURES...AND SOME LIGHT RAIN...IS NOW CENTERED JUST WEST OF
FLAGSTAFF. THIS LOW IS STILL FORECAST TO MOVE NORTHEASTWARD INTO
EXTREME NORTHWEST NEW MEXICO/SOUTHWEST COLORADO BY LATE THIS
AFTERNOON. THE SURFACE COLD FRONT HAS NOW MOVED INTO EASTERN ARIZONA
WITH MOST OF ITS ASSOCIATED SHOWER ACTIVITY NOW CONFINED TO EXTREME
EASTERN MARICOPA COUNTY AND POINTS EAST. SKIES SHOULD BEGIN TO CLEAR
OVER THE PHOENIX AREA OVER THE NEXT HOUR OR TWO...WITH MOSTLY SUNNY
SKIES EXPECTED BY LATE AFTERNOON. PRECIP AMOUNT ACROSS THE GREATER
PHOENIX AREA HAVE BEEN ON THE LIGHT SIDE...MAINLY 0.05 INCH OR
LESS...WITH ISOLATED AREAS IN NORTH PHOENIX SEEING AS MUCH AS 0.10
OF AN INCH. OTHER THAN SOME ADJUSTMENTS IN SHORT-TERM TEMPERATURE
TRENDS...CURRENT GRIDDED FORECASTS ARE LOOKING QUITE GOOD...NO
UPDATES ARE PLANNED AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO MOVE THROUGH THE AREA THIS
MORNING. REGIONAL RADAR MOSAIC INDICATES SHOWERS DEVELOPING ACROSS
THE PHOENIX AREA...HOWEVER THE BACK EDGE OF THE BROKEN BAND OF
RAINFALL IS ALREADY EXITING SOUTHEAST CALIFORNIA. BASED ON CURRENT
TRENDS...I WOULD EXPECT PRECIP TO BEGIN CLEARING OUT OF THE PHOENIX
AREA BY MID MORNING /15Z OR SO/...WITH CLEARING SKIES AND DRY
CONDITIONS ACROSS THE ENTIRE FORECAST AREA BY MID AFTERNOON. THIS
THINKING IS IN LINE WITH PREVIOUS FORECASTS AND CONFIRMED BY THIS
MORNINGS 00Z MODEL DATA...AS WELL AS THE LATEST HRRR AND HI-RES
SUITE OF WRF MODELS. INHERITED FORECAST WAS ONLY MODIFIED SLIGHTLY
TO INCREASE POPS ACROSS THE PHOENIX AREA TO AROUND 40 PERCENT AND TO
AROUND 90 PERCENT IN THE MOUNTAINS EAST OF THE METRO. RAINFALL
TOTALS HAVE BEEN VERY LIGHT SO FAR...ONLY A FEW HUNDREDTHS OBSERVED
ACROSS SOUTHEAST CALIFORNIA AND ONLY A TRACE AT YUMA. HAD THESE
VALUES BEEN HIGHER I WOULD CONTEMPLATE MUCH HIGHER POPS ACROSS THE
METRO BUT THIS IS SHAPING UP TO BE A WIDESPREAD BUT SHORT LIVED
SPOTTY LIGHT RAIN EVENT. AS HAS ALSO BEEN ADVERTISED...THE MOST
NOTEWORTHY EFFECT WILL BE SUBSTANTIALLY COOLER TEMPERATURES THIS
AFTERNOON. MOST DESERT LOCALES WILL ONLY TOP OUT IN THE LOWER 70S
THIS AFTERNOON...ABOUT 15-20 DEGREES BELOW NORMAL FOR OCT 10.
THE FORECAST TURNS VERY TRANQUIL ACROSS THE LOWER DESERTS FROM
FRIDAY ONWARD AS BROAD NORTHWESTERLY FLOW ESTABLISHES ITSELF ACROSS
THE AREA. THIS WILL RESULT IN DRY WEATHER WITH A GRADUAL WARMING
TREND THROUGH NEXT WEEK. THE EUROPEAN AND GFS...ALONG WITH THEIR
RESPECTIVE ENSEMBLES...INDICATE A LOW MOVING THROUGH NORTHERN
ARIZONA LATE THIS WEEKEND WITH A SECONDARY SHORTWAVE TROUGH SWEEPING
THROUGH EARLY NEXT WEEK. AT THIS POINT IT WOULD APPEAR ANY IMPACTS
THIS FAR SOUTH SHOULD BE MINIMAL/NEGLIGIBLE FOR A COUPLE OF REASONS.
THE PROLONGED OVER-LAND TRAJECTORY OF THE LOW WILL RESULT IN
EXTREMELY LOW PWATS /ONLY 0.5-0.6 INCHES/ AS THE TROUGH MOVES
THROUGH THIS WEEKEND AS WELL AS WITH THE SECONDARY SHORTWAVE.
SECOND...THE BEST ISENTROPIC LIFT IS DISPLACED WELL TO THE NORTH OF
THE AREA...MORE INTO THE FOUR CORNERS AREA THAN SOUTH-CENTRAL
ARIZONA. PERHAPS A SUBTLE INCREASE IN WINDS WITH THE TROUGHS BUT
NOTHING OF ANY SIGNIFICANCE.
AS MENTIONED BEFORE...TEMPS WILL GRADUALLY RETURN TO NORMAL BY MID
WEEK. HIGHS IN THE UPPER 80S WILL BE COMMON ACROSS THE DESERTS ALONG
WITH LOWS IN THE LOWER 60S.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
DEEPER MOISTURE HAS MOVED EAST OF THE PHOENIX AREA...THOUGH RESIDUAL
LOW-LEVEL MOISTURE WILL YIELD SCATTERED STRATOCU WITH BASES AROUND
4-5K FT. CLOUDS WILL LIFT AND DISSIPATE LATE THIS AFTERNOON...GIVING
WAY TO CLEAR SKIES OVERNIGHT. OTHERWISE...WINDS WILL CONTINUE TO
ABATE THIS AFTERNOON...GRADUALLY VEERING TO THE NORTHWEST BEFORE
FINALLY BECOMING EASTERLY THIS EVENING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
NO AVIATION WEATHER IMPACTS. LIGHT WINDS AND GENERALLY CLEAR SKIES
EXPECTED THROUGH FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
CYCLONIC FLOW WILL PREDOMINATE ACROSS THE INTERMOUNTAIN
WEST...RESULTING IN A PERSISTENT WESTERLY FLOW ALONG WITH A DRYING
TREND ACROSS THE REGION. MINIMUM HUMIDITIES WILL GENERALLY RANGE
FROM THE LOW TO MID TEENS THROUGH THE WEEKEND...LOWERING A FEW
PERCENT BY EARLY NEXT WEEK. TEMPERATURES WILL WARM THROUGH THE
WEEKEND BEFORE LEVELING OFF NEXT WEEK TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS. THERE IS THE POTENTIAL FOR GUSTY NORTH WINDS DOWN
THE LOWER COLORADO RIVER VALLEY EARLY NEXT WEEK BUT DUE TO LOWER
CONFIDENCE...WILL KEEP VALUES CLOSER TO CLIMATOLOGICAL NORMALS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS
AVIATION....HIRSCH
FIRE WEATHER...CB/HIRSCH
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
850 AM MST THU OCT 10 2013
&&
.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM WILL QUICKLY MOVE THROUGH THE AREA
TODAY...RESULTING IN SCATTERED SHOWERS THIS MORNING AND
SUBSTANTIALLY COOLER THAN NORMAL TEMPERATURES BY THIS AFTERNOON. DRY
CONDITIONS WITH A SLOW WARMING TREND IS EXPECTED TO BEGIN ON
FRIDAY...THEN CONTINUE INTO EARLY NEXT WEEK.
&&
.DISCUSSION...
THE UPPER LOW THAT HAS BROUGHT OUR CWA MUCH COOLER
TEMPERATURES...AND SOME LIGHT RAIN...IS NOW CENTERED JUST WEST OF
FLAGSTAFF. THIS LOW IS STILL FORECAST TO MOVE NORTHEASTWARD INTO
EXTREME NORTHWEST NEW MEXICO/SOUTHWEST COLORADO BY LATE THIS
AFTERNOON. THE SURFACE COLD FRONT HAS NOW MOVED INTO EASTERN ARIZONA
WITH MOST OF ITS ASSOCIATED SHOWER ACTIVITY NOW CONFINED TO EXTREME
EASTERN MARICOPA COUNTY AND POINTS EAST. SKIES SHOULD BEGIN TO CLEAR
OVER THE PHOENIX AREA OVER THE NEXT HOUR OR TWO...WITH MOSTLY SUNNY
SKIES EXPECTED BY LATE AFTERNOON. PRECIP AMOUNT ACROSS THE GREATER
PHOENIX AREA HAVE BEEN ON THE LIGHT SIDE...MAINLY 0.05 INCH OR
LESS...WITH ISOLATED AREAS IN NORTH PHOENIX SEEING AS MUCH AS 0.10
OF AN INCH. OTHER THAN SOME ADJUSTMENTS IN SHORT-TERM TEMPERATURE
TRENDS...CURRENT GRIDDED FORECASTS ARE LOOKING QUITE GOOD...NO
UPDATES ARE PLANNED AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO MOVE THROUGH THE AREA THIS
MORNING. REGIONAL RADAR MOSAIC INDICATES SHOWERS DEVELOPING ACROSS
THE PHOENIX AREA...HOWEVER THE BACK EDGE OF THE BROKEN BAND OF
RAINFALL IS ALREADY EXITING SOUTHEAST CALIFORNIA. BASED ON CURRENT
TRENDS...I WOULD EXPECT PRECIP TO BEGIN CLEARING OUT OF THE PHOENIX
AREA BY MID MORNING /15Z OR SO/...WITH CLEARING SKIES AND DRY
CONDITIONS ACROSS THE ENTIRE FORECAST AREA BY MID AFTERNOON. THIS
THINKING IS IN LINE WITH PREVIOUS FORECASTS AND CONFIRMED BY THIS
MORNINGS 00Z MODEL DATA...AS WELL AS THE LATEST HRRR AND HI-RES
SUITE OF WRF MODELS. INHERITED FORECAST WAS ONLY MODIFIED SLIGHTLY
TO INCREASE POPS ACROSS THE PHOENIX AREA TO AROUND 40 PERCENT AND TO
AROUND 90 PERCENT IN THE MOUNTAINS EAST OF THE METRO. RAINFALL
TOTALS HAVE BEEN VERY LIGHT SO FAR...ONLY A FEW HUNDREDTHS OBSERVED
ACROSS SOUTHEAST CALIFORNIA AND ONLY A TRACE AT YUMA. HAD THESE
VALUES BEEN HIGHER I WOULD CONTEMPLATE MUCH HIGHER POPS ACROSS THE
METRO BUT THIS IS SHAPING UP TO BE A WIDESPREAD BUT SHORT LIVED
SPOTTY LIGHT RAIN EVENT. AS HAS ALSO BEEN ADVERTISED...THE MOST
NOTEWORTHY EFFECT WILL BE SUBSTANTIALLY COOLER TEMPERATURES THIS
AFTERNOON. MOST DESERT LOCALES WILL ONLY TOP OUT IN THE LOWER 70S
THIS AFTERNOON...ABOUT 15-20 DEGREES BELOW NORMAL FOR OCT 10.
THE FORECAST TURNS VERY TRANQUIL ACROSS THE LOWER DESERTS FROM
FRIDAY ONWARD AS BROAD NORTHWESTERLY FLOW ESTABLISHES ITSELF ACROSS
THE AREA. THIS WILL RESULT IN DRY WEATHER WITH A GRADUAL WARMING
TREND THROUGH NEXT WEEK. THE EUROPEAN AND GFS...ALONG WITH THEIR
RESPECTIVE ENSEMBLES...INDICATE A LOW MOVING THROUGH NORTHERN
ARIZONA LATE THIS WEEKEND WITH A SECONDARY SHORTWAVE TROUGH SWEEPING
THROUGH EARLY NEXT WEEK. AT THIS POINT IT WOULD APPEAR ANY IMPACTS
THIS FAR SOUTH SHOULD BE MINIMAL/NEGLIGIBLE FOR A COUPLE OF REASONS.
THE PROLONGED OVER-LAND TRAJECTORY OF THE LOW WILL RESULT IN
EXTREMELY LOW PWATS /ONLY 0.5-0.6 INCHES/ AS THE TROUGH MOVES
THROUGH THIS WEEKEND AS WELL AS WITH THE SECONDARY SHORTWAVE.
SECOND...THE BEST ISENTROPIC LIFT IS DISPLACED WELL TO THE NORTH OF
THE AREA...MORE INTO THE FOUR CORNERS AREA THAN SOUTH-CENTRAL
ARIZONA. PERHAPS A SUBTLE INCREASE IN WINDS WITH THE TROUGHS BUT
NOTHING OF ANY SIGNIFICANCE.
AS MENTIONED BEFORE...TEMPS WILL GRADUALLY RETURN TO NORMAL BY MID
WEEK. HIGHS IN THE UPPER 80S WILL BE COMMON ACROSS THE DESERTS ALONG
WITH LOWS IN THE LOWER 60S.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SURFACE COLD FRONT WILL WORK EASTWARD ACROSS THE CENTRAL DESERTS
THIS MORNING...LOWERING CIGS GENLY INTO THE 5-7K RANGE. ISOLD CIGS
DOWN TO AROUND 4K ARE POSSIBLE WITH MODERATE SHOWERS. EXPECT
CLEARING BY LATE MORNING...16-18Z...AS FRONT MOVES OFF TO THE EAST
AND A DRIER MORE SUBSIDENT AIRMASS MOVES IN. FEW-SCT CU WILL PERSIST
THRU THE AFTERNOON THEN DISSIPATE AROUND SUNSET. WINDS TO FAVOR THE
WEST THRU THE EVENING HOURS TODAY GENLY 15KT OR LESS...AND MAY
BRIEFLY BACK AROUND TO THE SOUTHEAST EARLY THIS MORNING AHEAD OF THE
APPROACHING FRONT. AS THE FRONT PASSES...LIGHT TO MODERATE SHOWERS
WILL DOMINATE... CANNOT RULE OUT AN ISOLD THUNDERSTORM BUT THIS IDEA
WILL NOT BE MENTIONED IN THE TAFS DUE TO LOW PROBABILITY.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
EXPECT CLEARING FROM THE WEST THIS MORNING AS A SURFACE COLD FRONT
MOVES EAST OF THE AREA AND INTO THE CENTRAL AZ DESERTS. FEW-SCT CU
WITH BASES 6-9K FEET ARE EXPECTED THIS MORNING INTO THE AFTN HOURS
WITH SKIES BECOMING GENLY CLEAR BY SUNSET. WINDS TO FAVOR THE
SOUTHWEST TO WEST NEXT 24 HOURS WITH SPEEDS MOSTLY 15KT OR LESS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
CYCLONIC FLOW WILL PREDOMINATE ACROSS THE INTERMOUNTAIN
WEST...RESULTING IN A PERSISTENT WESTERLY FLOW ALONG WITH A DRYING
TREND ACROSS THE REGION. MINIMUM HUMIDITIES WILL GENERALLY RANGE
FROM THE LOW TO MID TEENS THROUGH THE WEEKEND...LOWERING A FEW
PERCENT BY EARLY NEXT WEEK. TEMPERATURES WILL WARM THROUGH THE
WEEKEND BEFORE LEVELING OFF NEXT WEEK TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS. THERE IS THE POTENTIAL FOR GUSTY NORTH WINDS DOWN
THE LOWER COLORADO RIVER VALLEY EARLY NEXT WEEK BUT DUE TO LOWER
CONFIDENCE...WILL KEEP VALUES CLOSER TO CLIMATOLOGICAL NORMALS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS
AVIATION....CB
FIRE WEATHER...CB/HIRSCH
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
325 AM MST THU OCT 10 2013
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM WILL QUICKLY MOVE THROUGH THE AREA
TODAY...RESULTING IN SCATTERED SHOWERS THIS MORNING AND
SUBSTANTIALLY COOLER THAN NORMAL TEMPERATURES BY THIS AFTERNOON. DRY
CONDITIONS WITH A SLOW WARMING TREND IS EXPECTED TO BEGIN ON
FRIDAY...THEN CONTINUE INTO EARLY NEXT WEEK.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO MOVE THROUGH THE AREA THIS
MORNING. REGIONAL RADAR MOSAIC INDICATES SHOWERS DEVELOPING ACROSS
THE PHOENIX AREA...HOWEVER THE BACK EDGE OF THE BROKEN BAND OF
RAINFALL IS ALREADY EXITING SOUTHEAST CALIFORNIA. BASED ON CURRENT
TRENDS...I WOULD EXPECT PRECIP TO BEGIN CLEARING OUT OF THE PHOENIX
AREA BY MID MORNING /15Z OR SO/...WITH CLEARING SKIES AND DRY
CONDITIONS ACROSS THE ENTIRE FORECAST AREA BY MID AFTERNOON. THIS
THINKING IS IN LINE WITH PREVIOUS FORECASTS AND CONFIRMED BY THIS
MORNINGS 00Z MODEL DATA...AS WELL AS THE LATEST HRRR AND HI-RES
SUITE OF WRF MODELS. INHERITED FORECAST WAS ONLY MODIFIED SLIGHTLY
TO INCREASE POPS ACROSS THE PHOENIX AREA TO AROUND 40 PERCENT AND TO
AROUND 90 PERCENT IN THE MOUNTAINS EAST OF THE METRO. RAINFALL
TOTALS HAVE BEEN VERY LIGHT SO FAR...ONLY A FEW HUNDREDTHS OBSERVED
ACROSS SOUTHEAST CALIFORNIA AND ONLY A TRACE AT YUMA. HAD THESE
VALUES BEEN HIGHER I WOULD CONTEMPLATE MUCH HIGHER POPS ACROSS THE
METRO BUT THIS IS SHAPING UP TO BE A WIDESPREAD BUT SHORT LIVED
SPOTTY LIGHT RAIN EVENT. AS HAS ALSO BEEN ADVERTISED...THE MOST
NOTEWORTHY EFFECT WILL BE SUBSTANTIALLY COOLER TEMPERATURES THIS
AFTERNOON. MOST DESERT LOCALES WILL ONLY TOP OUT IN THE LOWER 70S
THIS AFTERNOON...ABOUT 15-20 DEGREES BELOW NORMAL FOR OCT 10.
THE FORECAST TURNS VERY TRANQUIL ACROSS THE LOWER DESERTS FROM
FRIDAY ONWARD AS BROAD NORTHWESTERLY FLOW ESTABLISHES ITSELF ACROSS
THE AREA. THIS WILL RESULT IN DRY WEATHER WITH A GRADUAL WARMING
TREND THROUGH NEXT WEEK. THE EUROPEAN AND GFS...ALONG WITH THEIR
RESPECTIVE ENSEMBLES...INDICATE A LOW MOVING THROUGH NORTHERN
ARIZONA LATE THIS WEEKEND WITH A SECONDARY SHORTWAVE TROUGH SWEEPING
THROUGH EARLY NEXT WEEK. AT THIS POINT IT WOULD APPEAR ANY IMPACTS
THIS FAR SOUTH SHOULD BE MINIMAL/NEGLIGIBLE FOR A COUPLE OF REASONS.
THE PROLONGED OVER-LAND TRAJECTORY OF THE LOW WILL RESULT IN
EXTREMELY LOW PWATS /ONLY 0.5-0.6 INCHES/ AS THE TROUGH MOVES
THROUGH THIS WEEKEND AS WELL AS WITH THE SECONDARY SHORTWAVE.
SECOND...THE BEST ISENTROPIC LIFT IS DISPLACED WELL TO THE NORTH OF
THE AREA...MORE INTO THE FOUR CORNERS AREA THAN SOUTH-CENTRAL
ARIZONA. PERHAPS A SUBTLE INCREASE IN WINDS WITH THE TROUGHS BUT
NOTHING OF ANY SIGNIFICANCE.
AS MENTIONED BEFORE...TEMPS WILL GRADUALLY RETURN TO NORMAL BY MID
WEEK. HIGHS IN THE UPPER 80S WILL BE COMMON ACROSS THE DESERTS ALONG
WITH LOWS IN THE LOWER 60S.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SURFACE COLD FRONT WILL WORK EASTWARD ACROSS THE CENTRAL DESERTS
THIS MORNING...LOWERING CIGS GENLY INTO THE 5-7K RANGE. ISOLD CIGS
DOWN TO AROUND 4K ARE POSSIBLE WITH MODERATE SHOWERS. EXPECT
CLEARING BY LATE MORNING...16-18Z...AS FRONT MOVES OFF TO THE EAST
AND A DRIER MORE SUBSIDENT AIRMASS MOVES IN. FEW-SCT CU WILL PERSIST
THRU THE AFTERNOON THEN DISSIPATE AROUND SUNSET. WINDS TO FAVOR THE
WEST THRU THE EVENING HOURS TODAY GENLY 15KT OR LESS...AND MAY
BRIEFLY BACK AROUND TO THE SOUTHEAST EARLY THIS MORNING AHEAD OF THE
APPROACHING FRONT. AS THE FRONT PASSES...LIGHT TO MODERATE SHOWERS
WILL DOMINATE... CANNOT RULE OUT AN ISOLD THUNDERSTORM BUT THIS IDEA
WILL NOT BE MENTIONED IN THE TAFS DUE TO LOW PROBABILITY.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
EXPECT CLEARING FROM THE WEST THIS MORNING AS A SURFACE COLD FRONT
MOVES EAST OF THE AREA AND INTO THE CENTRAL AZ DESERTS. FEW-SCT CU
WITH BASES 6-9K FEET ARE EXPECTED THIS MORNING INTO THE AFTN HOURS
WITH SKIES BECOMING GENLY CLEAR BY SUNSET. WINDS TO FAVOR THE
SOUTHWEST TO WEST NEXT 24 HOURS WITH SPEEDS MOSTLY 15KT OR LESS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
CYCLONIC FLOW WILL PREDOMINATE ACROSS THE INTERMOUNTAIN
WEST...RESULTING IN A PERSISTENT WESTERLY FLOW ALONG WITH A DRYING
TREND ACROSS THE REGION. MINIMUM HUMIDITIES WILL GENERALLY RANGE
FROM THE LOW TO MID TEENS THROUGH THE WEEKEND...LOWERING A FEW
PERCENT BY EARLY NEXT WEEK. TEMPERATURES WILL WARM THROUGH THE
WEEKEND BEFORE LEVELING OFF NEXT WEEK TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS. THERE IS THE POTENTIAL FOR GUSTY NORTH WINDS DOWN
THE LOWER COLORADO RIVER VALLEY EARLY NEXT WEEK BUT DUE TO LOWER
CONFIDENCE...WILL KEEP VALUES CLOSER TO CLIMATOLOGICAL NORMALS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION....CB
FIRE WEATHER...CB/HIRSCH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
230 AM MST THU OCT 10 2013
.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM WILL QUICKLY MOVE THROUGH THE AREA
TODAY...RESULTING IN SCATTERED SHOWERS THIS MORNING AND
SUBSTANTIALLY COOLER THAN NORMAL TEMPERATURES BY THIS AFTERNOON. DRY
CONDITIONS WITH A SLOW WARMING TREND IS EXPECTED TO BEGIN ON
FRIDAY...THEN CONTINUE INTO EARLY NEXT WEEK.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO MOVE THROUGH THE AREA THIS
MORNING. REGIONAL RADAR MOSAIC INDICATES SHOWERS DEVELOPING ACROSS
THE PHOENIX AREA...HOWEVER THE BACK EDGE OF THE BROKEN BAND OF
RAINFALL IS ALREADY EXITING SOUTHEAST CALIFORNIA. BASED ON CURRENT
TRENDS...I WOULD EXPECT PRECIP TO BEGIN CLEARING OUT OF THE PHOENIX
AREA BY MID MORNING /15Z OR SO/...WITH CLEARING SKIES AND DRY
CONDITIONS ACROSS THE ENTIRE FORECAST AREA BY MID AFTERNOON. THIS
THINKING IS IN LINE WITH PREVIOUS FORECASTS AND CONFIRMED BY THIS
MORNINGS 00Z MODEL DATA...AS WELL AS THE LATEST HRRR AND HI-RES
SUITE OF WRF MODELS. INHERITED FORECAST WAS ONLY MODIFIED SLIGHTLY
TO INCREASE POPS ACROSS THE PHOENIX AREA TO AROUND 40 PERCENT AND TO
AROUND 90 PERCENT IN THE MOUNTAINS EAST OF THE METRO. RAINFALL
TOTALS HAVE BEEN VERY LIGHT SO FAR...ONLY A FEW HUNDREDTHS OBSERVED
ACROSS SOUTHEAST CALIFORNIA AND ONLY A TRACE AT YUMA. HAD THESE
VALUES BEEN HIGHER I WOULD CONTEMPLATE MUCH HIGHER POPS ACROSS THE
METRO BUT THIS IS SHAPING UP TO BE A WIDESPREAD BUT SHORT LIVED
SPOTTY LIGHT RAIN EVENT. AS HAS ALSO BEEN ADVERTISED...THE MOST
NOTEWORTHY EFFECT WILL BE SUBSTANTIALLY COOLER TEMPERATURES THIS
AFTERNOON. MOST DESERT LOCALES WILL ONLY TOP OUT IN THE LOWER 70S
THIS AFTERNOON...ABOUT 15-20 DEGREES BELOW NORMAL FOR OCT 10.
THE FORECAST TURNS VERY TRANQUIL ACROSS THE LOWER DESERTS FROM
FRIDAY ONWARD AS BROAD NORTHWESTERLY FLOW ESTABLISHES ITSELF ACROSS
THE AREA. THIS WILL RESULT IN DRY WEATHER WITH A GRADUAL WARMING
TREND THROUGH NEXT WEEK. THE EUROPEAN AND GFS...ALONG WITH THEIR
RESPECTIVE ENSEMBLES...INDICATE A LOW MOVING THROUGH NORTHERN
ARIZONA LATE THIS WEEKEND WITH A SECONDARY SHORTWAVE TROUGH SWEEPING
THROUGH EARLY NEXT WEEK. AT THIS POINT IT WOULD APPEAR ANY IMPACTS
THIS FAR SOUTH SHOULD BE MINIMAL/NEGLIGIBLE FOR A COUPLE OF REASONS.
THE PROLONGED OVER-LAND TRAJECTORY OF THE LOW WILL RESULT IN
EXTREMELY LOW PWATS /ONLY 0.5-0.6 INCHES/ AS THE TROUGH MOVES
THROUGH THIS WEEKEND AS WELL AS WITH THE SECONDARY SHORTWAVE.
SECOND...THE BEST ISENTROPIC LIFT IS DISPLACED WELL TO THE NORTH OF
THE AREA...MORE INTO THE FOUR CORNERS AREA THAN SOUTH-CENTRAL
ARIZONA. PERHAPS A SUBTLE INCREASE IN WINDS WITH THE TROUGHS BUT
NOTHING OF ANY SIGNIFICANCE.
AS MENTIONED BEFORE...TEMPS WILL GRADUALLY RETURN TO NORMAL BY MID
WEEK. HIGHS IN THE UPPER 80S WILL BE COMMON ACROSS THE DESERTS ALONG
WITH LOWS IN THE LOWER 60S.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
VIGOROUS AREA OF LOW PRESSURE NOW MOVING INTO SOUTHERN CALIFORNIA
TONIGHT AND WILL CONTINUE TO TREK EASTWARD INTO THURSDAY. SURFACE
FRONTAL PASSAGE EXPECTED TO INTERACT WITH A SOMEWHAT LIMITED
MOISTURE PROFILE...ALLOWING FOR SCATTERED LIGHT SHOWER DEVELOPMENT
POSSIBLE BY EARLY THURSDAY MORNING ACROSS CENTRAL ARIZONA. ALONG
WITH SHOWER ACTIVITY /VCSH TO SHRA AT MOST IN THE 06Z
TAFS/...STRATOCU DECKS AON 5KFT WILL BE POSSIBLE ACROSS PORTIONS OF
CENTRAL ARIZONA...INCLUDING THE PHOENIX AREA...THROUGH THE EARLY
MORNING HOURS. WINDS WILL REMAIN WESTERLY IN NATURE NEAR 10 TO 15KTS
WITH ISOLATED GUSTS OF 20KTS THROUGH EARLY MORNING. CONDITIONS WILL
GRADUALLY DRY...SKIES WILL SLOWLY CLEAR AND WINDS WILL BEGIN TO
RETREAT FROM ELEVATED OBSERVATIONS THROUGH THE DAY THURSDAY.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
CONTINUED ELEVATED WINDS...LIGHT SHOWER ACTIVITY AND MID LEVEL CIGS
ARE EXPECTED ACROSS SOUTHEAST CALIFORNIA TONIGHT. LARGE AREA OF LOW
PRESSURE MOVING THROUGH THE REGION WILL SUPPORT CONTINUED BREEZY
CONDITIONS...WITH GUSTS NEAR 20KTS POSSIBLE OVERNIGHT. LIGHT SHOWER
ACTIVITY WILL CLEAR EAST OF THE TERMINALS BY THURSDAY MORNING...WITH
GRADUALLY CLEARING SKIES AND LIGHT VARIABLE WINDS EXPECTED THURSDAY
AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
CYCLONIC FLOW WILL PREDOMINATE ACROSS THE INTERMOUNTAIN
WEST...RESULTING IN A PERSISTENT WESTERLY FLOW ALONG WITH A DRYING
TREND ACROSS THE REGION. TEMPERATURES WILL WARM THROUGH THE WEEKEND
BEFORE LEVELING OFF NEXT WEEK TO NEAR OR SLIGHTLY BELOW NORMAL
READINGS. THERE IS THE POTENTIAL FOR ANOTHER PERIOD OF GUSTY WINDS
PARTICULARLY DOWN THE CO RIVER VALLEY NEXT WEDNESDAY AS ANOTHER LOW
PRESSURE SYSTEM AFFECTS THE REGION. HOWEVER...UNCERTAINTY IS HIGH
WITH THIS SYSTEM AND THE OFFICIAL FORECAST REFLECTS WINDS CLOSER TO
CLIMATOLOGICAL NORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION....NOLTE
FIRE WEATHER...HIRSCH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
952 PM MDT FRI OCT 11 2013
.UPDATE...
ISSUED AT 951 PM MDT FRI OCT 11 2013
CLOUDS ARE STUBBORNLY HOLDING ON ACROSS PORTIONS OF WESTERN CO
THIS EVENING IN WESTERLY OROGRAPHIC FLOW ALOFT. KGJX RADAR HINTS
AT PATCHES OF LIGHT PRECIP STILL OVER THE FLATTOPS AND NORTHERN
MTNS DOWN T0 ABOUT VAIL...BUT THESE ECHOES WERE QUICKLY DIMINISHING.
THE MAIN UPPER TROUGH CONTINUES TO LIFT AWAY INTO THE CENTRAL AND
NORTHERN PLAINS. A TRANSITORY SHORTWAVE RIDGE SLIDES ACROSS OUR
AREA LATE TONIGHT AND EARLY SATURDAY. THE NEXT WEATHER SYSTEM
ANTICIPATED TO AFFECT OUR AREA WILL MOVE INTO THE PACIFIC NW ON
SATURDAY. HIGH CLOUDS AHEAD OF IT WERE ALREADY PUSHING INTO ID AND
NRN NV AND SHOULD SLIP ACROSS NE UT/NW CO SATURDAY MORNING. WILL
MAKE ONLY SOME MINOR CHANGES TO CLOUD GRIDS TONIGHT AND EARLY SAT
MORNING.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 301 PM MDT FRI OCT 11 2013
THE UPPER LOW RESPONSIBLE FOR THE MOUNTAIN SNOWFALL IS LIFTING
THROUGH THE NORTHERN PLAINS INTO MANITOBA OVERNIGHT. THE LAST WAVE
IN NW FLOW PASSED THIS AFTERNOON WITH LITTLE SENSIBLE WEATHER
EFFECT. EARLY AFTERNOON HEATING HAS PRODUCED CONVECTIVE CELLS
OVER THE NORTHERN AND CENTRAL MTNS. CLOUD TOPS HAVE STAYED BELOW
THE -20C ISOTHERM SO THUNDERSTORMS ARE NOT EXPECTED THROUGH THE
REMAINDER OF THE AFTERNOON. THE LATEST RAP AND NAM RUNS INDICATE
ONLY ANOTHER 0-2 CONVECTIVE INCHES WILL FALL IN THE NORTHERN
MOUNTAINS THIS AFTERNOON. SO HAVE CANCELLED THE WINTER WEATHER
HIGHLIGHTS. ALL SHOWERS TO END BEFORE MIDNIGHT. WITH VERY WET
SOILS THERE IS SOME POSSIBILITY OF PATCHY FRIDAY MORNING VALLEY
FOG. THE MODELED RH VALUES DO NOT SHOW LARGE AREAS OF MORNING
SATURATION THOUGH SO WILL LET THE NIGHT SHIFT REACT TO LOCALIZED
FOG IF NEEDED.
WEAK RIDGING PASSES QUICKLY ON SATURDAY BACKING THE FLOW ALOFT TO
SW. AFTERNOON TEMPERATURES REMAIN 3-8 DEGREES BELOW NORMAL. THE
NEXT PACIFIC TROUGH MAKES LANDFALL NEAR SEATTLE SATURDAY MORNING
AND DIGS TO NEAR RENO SATURDAY NIGHT. SW MTN WINDS STRENGTHEN
OVERNIGHT AND MID-HIGH LEVEL MOISTURE BEGINS TO INVADE NE UTAH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 301 PM MDT FRI OCT 11 2013
THE NEXT STORM SYSTEM WILL BE DROPPING INTO THE NORTHERN GREAT BASIN
ON SUNDAY WITH THE TROF TAKING ON A POSITIVE TILT BY THE DIGGING
JET ALOFT. THE DOWNSTREAM PORTION OF THE TROF WILL BE MOVING OVER
OUR CWA SUNDAY AFTERNOON WITH LARGE SCALE ASCENT BEING ENHANCED BY
A JET MAX ALOFT. THETA SURFACES DO NOT SHOW A STRONG FEED OF
MOISTURE INTO THIS SYSTEM BUT PWATS DO PUSH BACK TOWARD NORMAL
JUST UNDER HALF OF AN INCH AS THE LIFT MOVES OVERHEAD. POPS WILL
BE TRENDING UPWARD IN THE AFTERNOON...FAVORED OVER THE NORTHERN
MOUNTAIN EARLY ON...AS TOP DOWN SATURATION WE WORKING TO GET
PRECIPITATION TO THE GROUND. MID LEVEL TEMPS SUGGEST SNOW LEVELS
WILL AGAIN BE AOA 12000 FT SUNDAY AFTERNOON IN THE COLORADO
MOUNTAINS...AND CLOSER TO 10000 FEET OVER THE UINTAS. WEAK UPRIGHT
CONVECTION AND THE STRONGER ASCENT MAY BRING THESE LEVELS DOWN
THROUGH THE DAY BUT DO NOW SEE SIGNIFICANT PROBLEMS AT THE PASSES
UNTIL SUNDAY NIGHT INTO MONDAY. THE ASCENT WILL QUICKLY PROGRESS
OVER OUR CWA SUNDAY NIGHT AS THE JET MOVES EAST AND THE TROF LIFTS
NORTHEAST. COLD AIR MOVING IN BEHIND THE TROF LOOKS TO DROP SNOW
LEVELS DOWN TO 7000 FEET OR SO BUT SOUNDING IN THE NORTHERN
VALLEYS ARE NOT IMPRESSIVE. ATTM OUR NORTHERN MOUNTAINS LOOK TO BE
FAVORED FOR 3 TO 8 INCHES OF NEW SNOW BY MONDAY AFTERNOON. AS FOR
TEMPERATURES...SUNDAY LOOKS TO WARM TO NEAR SEASONAL LEVELS THANKS
TO SOUTHERLY FLOW AND DECENT MIXING. BEHIND THE TROF TEMPERATURES
COOL SOME DEGREES TO WELL BELOW NORMAL WHERE THEY LOOK TO REMAIN
THROUGH THE WEEK.
THOUGH THIS SYSTEM WILL BE EJECTING ONTO THE PLAINS EARLY NEXT
WEEK...ENERGY DROPPING BEHIND THIS LOW LOOKS TO CARVE OUT A
LINGERING TROF ACROSS THE GREAT BASIN. THE EURO SOLN HAS BEEN
HINTING AT THIS THE PAST FEW DAYS AS THE GFS REMAINS MUCH TOO
PROGRESSIVE. DOWNSTREAM BLOCKING OVER THE ATLANTIC AND A STRONGLY
AMPLIFIED RIDGE OVER THE EASTERN PACIFIC FAVORS LOW PRESSURE OVER
THE WESTERN CONUS. DETAILS STILL NOT DIALED IN BUT UNSETTLED WEATHER
LOOKS TO LINGER OVER THE CWA THROUGH MID WEEK. THERE MAY BE A
DOWNTURN TO PRECIPITATION THURSDAY INTO FRIDAY...BUT THE NEXT HIGH
LATITUDE SYSTEM WILL BE DROPPING DOWN THE WESTERN RIDGE INTO THE
NORTHERN ROCKIES BY LATE IN THE WEEK. THROUGH MOISTURE STARVED THE
NEXT BATCH OF ENERGY WILL HAVE MUCH COLDER AIR ASSOCIATED WITH IT
AND SHOULD LEAD TO BETTER SNOWFALL PRODUCTION GOING INTO
FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 951 PM MDT FRI OCT 11 2013
VFR CONDITIONS SHOULD PREVAIL THROUGH SATURDAY AT THE TAF SITES.
HOWEVER...BKN-OVC CIGS WILL HANG ON ACROSS THE NORTHERN AND CENTRAL
CO MTNS TILL ABOUT 09Z TONIGHT WITH MTN TOPS OCCASIONALLY OBSCURED
FROM MT WERNER /K3MW/ TO MONARCH PASS /KMYP/ TO TELLURIDE /KTEX/.
THE WESTERLY FLOW MAY ALSO BRING SOME PERIOD OF MVFR CIGS TO
KHDN...KSBS TONIGHT. PATCHY EARLY MORNING VALLEY FOG MAY THREATEN
SOME LOCAL FLIGHT OPERATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...JOE
LONG TERM...15
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
301 PM MDT THU OCT 10 2013
.SHORT TERM...UPPER TROF APPROACHING COLORADO FROM THE WEST THIS
AFTERNOON AND APPEARS THERE ARE TWO MAIN CIRCULATION CENTERS WITH
THE ENTIRE TROF. THE STRONGER ONE IS NOW APPROACHING SW COLORADO
WITH A WEAKER CIRCULATION OVER NORTHERN UTAH. SCATTERED SHOWERS
AND A FEW THUNDERSTORMS HAVE BEEN DEVELOPING OVER THE MOUNTAINS
BUT COVERAGE MORE SCATTERED WITH UNFAVORABLE SOUTH TO SOUTHEAST
MTN TOP FLOW. FLOW WILL BECOME MORE FAVORABLE TNT AS MTN TOP FLOW
SHIFTS MORE WESTERLY. SNOW PRODUCTION SHOULD INCREASE IN THE
MOUNTAINS ALONG WITH STRONG WESTERLY WINDS. HENCE...CURRENT
WINTER WEATHER ADVISORIES LOOK GOOD.
ACROSS NORTHEAST COLORADO...SURFACE BOUNDARY JUST SHIFTING EAST OF
DENVER WITH STRONG SOUTHEAST WINDS OVER THE PALMER DIVIDE AND
NORTHEAST PLAINS. STILL A CHANCE FOR SEVERE STORMS ON THE PLAINS
WITH STRONG SHEAR PROFILE AND MODERATE INSTABILITY. COULD EASILY
SEE HIGH WIND GUSTS GIVEN THE STRONG 50KT MID LEVEL FLOW. HIGHEST
CHANCES OF STORMS WILL BE OVER THE FAR PLAINS WITH CONVERGENCE AND
BETTER LOW LEVEL MOISTURE NOW INTO WESTERN KANSAS.
MAIN CONCERN FOR LATER TNT AND FRIDAY AM IS THE POTENTIAL FOR
HIGH WINDS OVER THE FOOTHILLS AND ADJACENT PLAINS. THIS LOOKS LIKE
A GOOD CASE FOR HIGH WINDS WITH EJECTING LOW FROM THE DESERT SOUTHWEST.
BOTH NAM AND RAP SHOWING CROSS BARRIER FLOW INCREASING 50-60KT
AFTER MIDNIGHT TONIGHT ALONG WITH STRONG MTN TOP STABILITY JUST
BELOW 700MB. ALSO MEAN STATE CRITICAL LAYER DEVELOPS AS WELL. A
FEW FACTORS AGAINST THE WINDS...AS DEEP UPSTREAM MOISTURE MAY
LIMIT THE MTN TOP STABILITY AND BEST SUBSIDENCE BEHIND THE TROF IS
JUST SOUTH AND EAST OF THE HIGH WIND AREA. ON THE OTHER
SIDE...SURFACE GRADIENT INCREASES TO AROUND 15MB FROM GJT TO DEN.
BOTTOM LINE...WILL UPGRADE THE WATCH TO WARNINGS FOR THE TARGETED
AREA WITH ENOUGH FACTORS IN FAVOR OF HIGH WINDS.
.LONG TERM...THE SECONDARY UPPER TROUGH WILL BE MOVING EAST OF THE
AREA FRIDAY NIGHT WITH ISOLATED SHOWERS CONTINUING ACROSS THE AREA.
AN UPPER RIDGE WILL BUILD OVER THE AREA SATURDAY BRINGING DRIER
WEATHER BEFORE ANOTHER WEATHER SYSTEM DIGS INTO THE GREAT BASIN
SUNDAY. A SURFACE LOW WILL BE FORMING TO THE NORTH OF THE STATE TO
CREATE GUSTY SOUTHERLY WINDS OVER THE PLAINS SATURDAY. SOUTHWEST
WINDS ALOFT WILL INCREASE TO BRING IN WARMER AIR SUNDAY BEFORE
MOISTURE IS DRAWN UP FROM THE SOUTH TO BRING SHOWERS AND POSSIBLE
THUNDERSTORMS OVER THE PLAINS. AT THE SAME TIME...MOISTURE FROM THE
INCOMING GREAT BASIN SYSTEM WILL SPREAD SHOWERS OVER THE MOUNTAINS.
THE ASSOCIATED COLD FRONT IS PROGGED TO PUSH DOWN ACROSS THE STATE
MONDAY AS THE UPPER TROUGH BEGINS TO LIFT NORTHEAST. RAIN SHOWERS
OVER THE PLAINS AND SNOW SHOWERS OVER THE MOUNTAINS WILL CONTINUE
FROM SUNDAY INTO MONDAY NIGHT...WITH A SLIGHT CHANCE THE RAIN COULD
CHANGE INTO SNOW AT LOWER ELEVATIONS MONDAY NIGHT.
TUESDAY IS WHEN THE MODELS BEGIN TO DIVERGE WITH THE UPPER TROUGH.
ECMWF AND THE CANADIAN MODEL KEEPS A LOW BACK IN THE GREAT BASIN TO
ANCHOR THE UPPER TROUGH OVER THE STATE LONGER WHILE THE GFS
CONTINUES TO MOVE THE TROUGH SOUTHEAST. WILL KEEP COLDER THAN NORMAL
TEMPERATURES AND A SLIGHT CHANCE OF PRECIP IN THE FORECAST WHILE
THESE DIFFERENCES ARE RESOLVED.
&&
.AVIATION...SURFACE BOUNDARY HAS PUSHED EAST OF DENVER AS ALL
TERMINALS HAVE NOW SHIFTED NORTHWEST. GIVEN THAT SHOWERS WILL BE
AROUND THROUGH EARLY EVENING WINDS WILL END UP BEING QUITE
VARIABLE AND WILL BE HARD TO PINPOINT SPECIFIC DIRECTIONS BUT
MOST LIKELY SOME SORT OF WESTERLY COMPONENT. WEST WINDS WILL
INCREASE AT BJC LATER TNT WITH POTENTIAL FOR HIGH WINDS AND GUSTS
IN EXCESS OF 50KT. THE WEST WINDS WILL BE LIGHTER AT DEN AND APA
WITH SPEEDS UP TO 25KT POSSIBLE.
&&
.HYDROLOGY...NO CONCERNS WITH MAINLY FAST MOVING STORMS THIS
AFTERNOON AND EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING FROM MIDNIGHT MDT TONIGHT THROUGH FRIDAY
MORNING FOR COZ035-036-038-039.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
FRIDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....KRIEDERMAN
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
942 AM MDT THU OCT 10 2013
.UPDATE...
&&
.SHORT TERM...UPPER LOW NOW MOVING EAST AND NORTHEAST ACROSS
WESTERN ARIZONA WITH GOOD PRECIP NOW OCCURRING OVER WESTERN
COLORADO. NORTH CENTRAL MOUNTAINS UNDER A STRONG SOUTH AND
SOUTHEAST MOUNTAIN TOP FLOW SO SEEING SOME STRONG WINDS ON MTN TOP
SENSORS IN THE 30 TO 50 MPH RANGE. THIS FLOW NOT GOOD FOR PRECIP
PRODUCTION AND HAVE LOWER POPS THIS AM FOR THE MOUNTAINS. AS THE
UPPER LOW NEARS COLORADO THIS AFTERNOON EXPECT INCREASING SHOWERS
IN THE MOUNTAINS WITH STRONG QG ASCENT. A MORE TRICKY FORECAST
OVER NORTHEAST COLORADO WITH THE STRONG ASCENT FIGHTING THE
DEVELOPING SOUTHERLY DOWNSLOPE FLOW OVER THE FRONT RANGE. LOWER
POPS IN ORDER HERE BUT STILL EXPECT SOME STRONG SOUTHERLY WINDS TO
DEVELOP WITH BETTER MIXING. ANY SHOWERS THAT DO DEVELOP WITH BE
ABLE TO TRANSFER THOSE STRONGER WINDS TO THE SURFACE. FURTHER
EAST...STILL A CHANCE FOR SEVERE STORMS AHEAD OF THE SURFACE TROF
WITH HIGH WINDS THE BIGGEST THREAT. CAPES NOT ALL THAT IMPRESSIVE
WITH ANYWHERE FROM 500 TO 1000J/KG AND GOOD SHEAR TO KEEP THE
THREAT GOING.
AS FOR CURRENT HILITESS...ADVISORY FOR MOUNTAINS LOOK GOOD
ESPECIALLY FOR TONIGHT AS OROGRAPHIC FLOW INCREASES. HIGH WINDS
LOOK MORE IFFY ESPECIALLY OVER LOWER FOOTHILLS AND ADJACENT
PLAINS. WILL LOOK MORE AT THAT FOR AFTERNOON PACKAGE.
.AVIATION...LIGHT AND VARIABLE WINDS THIS MORNING WITH SURFACE LOW
OVER DENVER. SATELLITE IMAGERY SHOWING CLEARING MOVING IN FROM THE
SOUTH...WHICH WILL ALLOW FOR BETTER MIXING BY EARLY THIS
AFTERNOON AS STRONG SOUTHERLY WINDS DEVELOP AT APA AND DENVER.
WEST OF THE SURFACE LOW WINDS WILL BE MORE NORTHERLY AND LIGHTER
AT BJC. STILL UNCLEAR ON THE PRECIP SIDE OF THINGS ON AREAL EXTENT
OF SHOWERS. STILL PLAY A LOW COVERAGE OF TS BUT GREATER CHANCE OF
WINDS AS PORTRAYED IN CURRENT TAFS. ONLY MINOR CHANGES TO TIMING
AND WINDS EXPECTED FOR 18Z ISSUANCES.
&&
.PREV DISCUSSION... /ISSUED 259 AM MDT THU OCT 10 2013/
SHORT TERM...RATHER STG SYSTEM OVER SRN CALIFORNIA EARLY THIS
MORNING WILL MOVE RAPIDLY ENE INTO WRN COLORADO BY THIS AFTN AND
THEN INTO NERN CO OVERNIGHT. MOISTURE WILL CONTINUE TO INCREASE
IN THE MTNS WITH PCPN BECOMING MORE WIDESPREAD LATER THIS AFTN AS
LAPSE RATES STEEPEN AND HEALTHY SHOT OF QG ASCENT MOVE INTO AREA.
MTN TOP WINDS WILL BE SSW WHICH IS NOT GREAT FOR OROGRAPHICS
WHICH WILL LIMIT SNOW AMOUNTS INITIALLY. EAST OF THE MTNS A SFC
LOW WILL INTENSIFY NEAR DENVER THIS AFTN WITH GUSTY SSW WINDS
DEVELOPING SOUTH OF A DENVER TO AKRON LINE. COULD SEE SOME GUSTS
IN THE 40-50 MPH RANGE OVER THE PALMER DIVIDE TOWARDS LIMON. FOR
NOW WILL NOT ISSUE A HIGH WIND WARNING OVER DOUGLAS...ELBERT AND
LINCOLN COUNTIES BUT SPEEDS MAY GET CLOSE TO WARNING CRITERIA FOR
A FEW HOURS BETWEEN 20Z AND 00Z. AS FOR TSTM CHANCES CAPES BY LATE
AFTN WILL RANGE FM 500-1000 J/KG OVER THE NERN PLAINS. A SFC
CONVERGENCE ZONE MAY DEVELOP FM NERN WELD ACROSS MORGAN INTO
WASHINGTON COUNTIES SO THIS WILL BE AN AREA TO WATCH FOR
CONVECTIVE DEVELOPMENT. SOUNDINGS SHOW SOME DECENT SHEAR BY LATE
AFTN INTO THE EARLY EVENING HOURS SO THERE COULD BE A FEW STORMS
WITH DAMAGING WINDS AND MARGINAL LARGE HAIL. AS FOR HIGHS THIS
AFTN READINGS COULD VARY QUITE A BIT OVER NERN CO DUE TO HIGH
LEVEL CLOUD COVER AND WEAK UPSLOPE BEHIND SFC LOW. FOR NOW WILL
KEEP READINGS IN THE LOWER TO MID 60S CLOSER TO THE FOOTHILLS AND
HAVE HIGHS IN THE LOWER TO MID 70S FURTHER EAST OVER THE PLAINS.
FOR TONIGHT AN UPPER LEVEL LOW WILL BE OVER NERN CO/WRN NE AND
WILL MOVE NE INTO NRN NEBRASKA BY 12Z FRI. AS THIS FEATURE MOVES
ACROSS THIS EVENING WOULD EXPECT A GOOD CHC OF SHOWERS AND STORMS
OVER THE FAR NERN PLAINS DURING THE EVENING HOURS WITH ACTIVITY
DECREASING AFTER MIDNIGHT. IN THE MTNS OROGRAPHICS WILL BECOME
MORE FAVORABLE AS WINDS BECOME WNW WITH CROSS-SECTIONS SHOWING
DECENT MOISTURE IN THE 700-500 MB LAYER. THUS SHOULD SEE SNOW
SHOWERS CONTINUE OVERNIGHT WITH ADVISORY AMOUNTS THRU FRI MORNING.
IN ADDITION GUSTY WINDS WILL ALSO OCCUR WITH AREAS OF BLOWING SNOW
OVER THE HIGHER PASSES. MEANWHILE IN AND NR THE FOOTHILLS A RATHER
STG LOW LVL GRADIENT WILL EXIST WITH RATHER STG SUBSIDENCE
DEVELOPING IN THE 06Z-12Z TIMEFRAME. CROSS-SECTIONS SHOW COMPONENT
ALONG WINDS INCREASING TO 60-65 KTS OVERNIGHT SO THERE WILL BE A
THREAT OF HIGH WINDS IN THE NORMALLY WINDY AREAS IN AND NR THE
FOOTHILLS. THUS WILL ISSUE A HIGH WIND WATCH FM 06Z TONIGHT THRU
15Z ON FRI.
LONG TERM...THE UPPER LEVEL TROUGH WILL CLOSE OFF AND INTENSIFY
OVER THE DAKOTAS ON FRIDAY AS IT LIFTS NORTHEAST. COLORADO WILL BE
UNDER A WEST-NORTHWEST FLOW ALOFT FRIDAY. STRONG DOWNSLOPE WINDS
BEHIND THIS SYSTEM WILL DECREASE FRIDAY MORNING AS THE TROUGH
EXITS THE AREA. THE FLOW ALOFT WILL REMAIN STRONG AND MOIST ENOUGH
FOR OROGRAPHIC SNOW OVER THE MOUNTAINS. SNOW WILL LIKELY INCREASE
IN COVERAGE AND INTENSITY FRIDAY AFTERNOON AS A SHORT WAVE TROUGH
MOVES OVER THE REGION. MAY BE ENOUGH LIFT WITH THIS SYSTEM TO
PRODUCE RAIN SHOWERS OVER THE PLAINS...MAINLY FRIDAY AFTERNOON AND
EVENING. ONCE THIS FEATURE EXITS THE AREA...DRY AND MILD
CONDITIONS WILL PREVAIL SATURDAY AS A WEAK RIDGE MOVES ACROSS THE
STATE.
MODELS STAY IN GOOD AGREEMENT THROUGH SUNDAY. THEY ARE SHOWING THE
NEXT TROUGH BOTTOMING OUT OVER NEVADA AND UTAH. THIS WILL PRODUCE A
SOUTHWEST FLOW ALOFT. BY AFTERNOON THERE MAY BE ENOUGH MOISTURE
EMBEDDED IN THE FLOW ALOFT TO PRODUCE A FEW MOUNTAIN SHOWERS.
TEMPERATURES WILL BE MILD WITH HIGHS IN THE 60S OVER NORTHEAST
COLORADO.
FOR MONDAY THROUGH WEDNESDAY...MODELS ARE SHOWING VARIOUS SOLUTIONS
WHICH LEADS TO A LOW CONFIDENCE FORECAST. GENERAL PATTERN IS THAT A
LARGE TROUGH WILL FORM OVER NORTHERN ROCKIES. THE MODELS SHOW A FEW
SHORT WAVE TROUGHS ROTATING AROUND THE LOW. HOWEVER...THE GFS IS
PROGRESSIVE WITH THE TROUGH AND HAS IT CENTERED OVER THE GREAT LAKES
WEDNESDAY AFTERNOON. THE ECMWF HAS IT OVER THE NORTHERN ROCKIES
THROUGH WEDNESDAY. WOULD EXPECT A PERIOD OR TWO OF BRIEF LIGHT
PRECIPITATION OUT OF THIS PATTERN. THE TROUGH DOES NOT DIG FAR
ENOUGH SOUTH TO PRODUCE A SIGNIFICANT STORM FOR COLORADO. WILL BROAD
BRUSH 5-20 POPS FOR EARLY NEXT WEEK. TEMPERATURES ARE EXPECTED TO BE
AT OR BELOW NORMAL UNDER THIS TYPE OF PATTERN
AVIATION...THRU MID AFTN WILL TREND TOWARDS THE HRRR FOR SFC
WINDS WHICH ARE GOING TO BE A NIGHTMARE TO FCST. AT THIS TIME
LOOKS LIKE INITIAL SFC LOW WILL HANG AROUND THE AIRPORT THRU 18Z
WITH WINDS BECOMING SSE ON THE EAST SIDE WHILE ON THE WEST SIDE
WINDS WILL BE MORE NNW. BY 20Z THE HRRR LIFTS THE LOW INTO SCNTRL
WELD COUNTY WITH WINDS SHIFTING TO THE SSW WITH SPEEDS IN THE
20-25 MPH RANGE WITH SOME GUSTS FM 35-40 MPH. MEANWHILE COULD SEE
SOME WDLY SCT HIGH BASED STORMS DVLP IN THE 20Z-00Z TIME FRAME
ALTHOUGH THE HRRR KEEPS MOST OF THIS ACTIVITY NORTH OF DIA. AS
FOR CLOUDS EARLY THIS MORNING THERE ARE SOME CEILINGS IN THE
3500-4000 FT RANGE FM BJC TO LONGMONT HOWEVER DUE TO HI LVL
CLOUDS DO NOT KNOW HOW FAR EAST THESE CLOUDS ARE. FOR NOW WILL
CONTINUE WITH A TEMPO GROUP FOR CEILINGS IN THE 4000 FT RANGE THRU
14Z. IF SFC LOW STAY WEST OF DIA THEN THESE LOWER CEILINGS MAY NOT
AFFECT THE AIRPORT.
FOR TONIGHT GUSTY SSW WINDS SHOULD BECOME MORE WLY BY 02Z WITH
SOME GUSTS TO 25 MPH THRU 06Z POSSIBLE. IN FACT THESE GUSTY WINDS
COULD CONTINUE THRU FRI MORNING IF STRONGER WINDS NR THE
FOOTHILLS MIX DOWN TO THE SFC.
HYDROLOGY...NO ISSUES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
COZ035-036-038-039.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
FRIDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....MEIER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
259 AM MDT THU OCT 10 2013
.SHORT TERM...RATHER STG SYSTEM OVER SRN CALIFORNIA EARLY THIS
MORNING WILL MOVE RAPIDLY ENE INTO WRN COLORADO BY THIS AFTN AND
THEN INTO NERN CO OVERNIGHT. MOISTURE WILL CONTINUE TO INCREASE
IN THE MTNS WITH PCPN BECOMING MORE WIDESPREAD LATER THIS AFTN AS
LAPSE RATES STEEPEN AND HEALTHY SHOT OF QG ASCENT MOVE INTO AREA.
MTN TOP WINDS WILL BE SSW WHICH IS NOT GREAT FOR OROGRAPHICS
WHICH WILL LIMIT SNOW AMOUNTS INITIALLY. EAST OF THE MTNS A SFC
LOW WILL INTENSIFY NEAR DENVER THIS AFTN WITH GUSTY SSW WINDS
DEVELOPING SOUTH OF A DENVER TO AKRON LINE. COULD SEE SOME GUSTS
IN THE 40-50 MPH RANGE OVER THE PALMER DIVIDE TOWARDS LIMON. FOR
NOW WILL NOT ISSUE A HIGH WIND WARNING OVER DOUGLAS...ELBERT AND
LINCOLN COUNTIES BUT SPEEDS MAY GET CLOSE TO WARNING CRITERIA FOR
A FEW HOURS BETWEEN 20Z AND 00Z. AS FOR TSTM CHANCES CAPES BY LATE
AFTN WILL RANGE FM 500-1000 J/KG OVER THE NERN PLAINS. A SFC
CONVERGENCE ZONE MAY DEVELOP FM NERN WELD ACROSS MORGAN INTO
WASHINGTON COUNTIES SO THIS WILL BE AN AREA TO WATCH FOR
CONVECTIVE DEVELOPMENT. SOUNDINGS SHOW SOME DECENT SHEAR BY LATE
AFTN INTO THE EARLY EVENING HOURS SO THERE COULD BE A FEW STORMS
WITH DAMAGING WINDS AND MARGINAL LARGE HAIL. AS FOR HIGHS THIS
AFTN READINGS COULD VARY QUITE A BIT OVER NERN CO DUE TO HIGH
LEVEL CLOUD COVER AND WEAK UPSLOPE BEHIND SFC LOW. FOR NOW WILL
KEEP READINGS IN THE LOWER TO MID 60S CLOSER TO THE FOOTHILLS AND
HAVE HIGHS IN THE LOWER TO MID 70S FURTHER EAST OVER THE PLAINS.
FOR TONIGHT AN UPPER LEVEL LOW WILL BE OVER NERN CO/WRN NE AND
WILL MOVE NE INTO NRN NEBRASKA BY 12Z FRI. AS THIS FEATURE MOVES
ACROSS THIS EVENING WOULD EXPECT A GOOD CHC OF SHOWERS AND STORMS
OVER THE FAR NERN PLAINS DURING THE EVENING HOURS WITH ACTIVITY
DECREASING AFTER MIDNIGHT. IN THE MTNS OROGRAPHICS WILL BECOME
MORE FAVORABLE AS WINDS BECOME WNW WITH CROSS-SECTIONS SHOWING
DECENT MOISTURE IN THE 700-500 MB LAYER. THUS SHOULD SEE SNOW
SHOWERS CONTINUE OVERNIGHT WITH ADVISORY AMOUNTS THRU FRI MORNING.
IN ADDITION GUSTY WINDS WILL ALSO OCCUR WITH AREAS OF BLOWING SNOW
OVER THE HIGHER PASSES. MEANWHILE IN AND NR THE FOOTHILLS A RATHER
STG LOW LVL GRADIENT WILL EXIST WITH RATHER STG SUBSIDENCE
DEVELOPING IN THE 06Z-12Z TIMEFRAME. CROSS-SECTIONS SHOW COMPONENT
ALONG WINDS INCREASING TO 60-65 KTS OVERNIGHT SO THERE WILL BE A
THREAT OF HIGH WINDS IN THE NORMALLY WINDY AREAS IN AND NR THE
FOOTHILLS. THUS WILL ISSUE A HIGH WIND WATCH FM 06Z TONIGHT THRU
15Z ON FRI.
.LONG TERM...THE UPPER LEVEL TROUGH WILL CLOSE OFF AND INTENSIFY
OVER THE DAKOTAS ON FRIDAY AS IT LIFTS NORTHEAST. COLORADO WILL BE
UNDER A WEST-NORTHWEST FLOW ALOFT FRIDAY. STRONG DOWNSLOPE WINDS
BEHIND THIS SYSTEM WILL DECREASE FRIDAY MORNING AS THE TROUGH
EXITS THE AREA. THE FLOW ALOFT WILL REMAIN STRONG AND MOIST ENOUGH
FOR OROGRAPHIC SNOW OVER THE MOUNTAINS. SNOW WILL LIKELY INCREASE
IN COVERAGE AND INTENSITY FRIDAY AFTERNOON AS A SHORT WAVE TROUGH
MOVES OVER THE REGION. MAY BE ENOUGH LIFT WITH THIS SYSTEM TO
PRODUCE RAIN SHOWERS OVER THE PLAINS...MAINLY FRIDAY AFTERNOON AND
EVENING. ONCE THIS FEATURE EXITS THE AREA...DRY AND MILD
CONDITIONS WILL PREVAIL SATURDAY AS A WEAK RIDGE MOVES ACROSS THE
STATE.
MODELS STAY IN GOOD AGREEMENT THROUGH SUNDAY. THEY ARE SHOWING THE
NEXT TROUGH BOTTOMING OUT OVER NEVADA AND UTAH. THIS WILL PRODUCE A
SOUTHWEST FLOW ALOFT. BY AFTERNOON THERE MAY BE ENOUGH MOISTURE
EMBEDDED IN THE FLOW ALOFT TO PRODUCE A FEW MOUNTAIN SHOWERS.
TEMPERATURES WILL BE MILD WITH HIGHS IN THE 60S OVER NORTHEAST
COLORADO.
FOR MONDAY THROUGH WEDNESDAY...MODELS ARE SHOWING VARIOUS SOLUTIONS
WHICH LEADS TO A LOW CONFIDENCE FORECAST. GENERAL PATTERN IS THAT A
LARGE TROUGH WILL FORM OVER NORTHERN ROCKIES. THE MODELS SHOW A FEW
SHORT WAVE TROUGHS ROTATING AROUND THE LOW. HOWEVER...THE GFS IS
PROGRESSIVE WITH THE TROUGH AND HAS IT CENTERED OVER THE GREAT LAKES
WEDNESDAY AFTERNOON. THE ECMWF HAS IT OVER THE NORTHERN ROCKIES
THROUGH WEDNESDAY. WOULD EXPECT A PERIOD OR TWO OF BRIEF LIGHT
PRECIPITATION OUT OF THIS PATTERN. THE TROUGH DOES NOT DIG FAR
ENOUGH SOUTH TO PRODUCE A SIGNIFICANT STORM FOR COLORADO. WILL BROAD
BRUSH 5-20 POPS FOR EARLY NEXT WEEK. TEMPERATURES ARE EXPECTED TO BE
AT OR BELOW NORMAL UNDER THIS TYPE OF PATTERN
&&
.AVIATION...THRU MID AFTN WILL TREND TOWARDS THE HRRR FOR SFC
WINDS WHICH ARE GOING TO BE A NIGHTMARE TO FCST. AT THIS TIME
LOOKS LIKE INITIAL SFC LOW WILL HANG AROUND THE AIRPORT THRU 18Z
WITH WINDS BECOMING SSE ON THE EAST SIDE WHILE ON THE WEST SIDE
WINDS WILL BE MORE NNW. BY 20Z THE HRRR LIFTS THE LOW INTO SCNTRL
WELD COUNTY WITH WINDS SHIFTING TO THE SSW WITH SPEEDS IN THE
20-25 MPH RANGE WITH SOME GUSTS FM 35-40 MPH. MEANWHILE COULD SEE
SOME WDLY SCT HIGH BASED STORMS DVLP IN THE 20Z-00Z TIME FRAME
ALTHOUGH THE HRRR KEEPS MOST OF THIS ACTIVITY NORTH OF DIA. AS
FOR CLOUDS EARLY THIS MORNING THERE ARE SOME CEILINGS IN THE
3500-4000 FT RANGE FM BJC TO LONGMONT HOWEVER DUE TO HI LVL
CLOUDS DO NOT KNOW HOW FAR EAST THESE CLOUDS ARE. FOR NOW WILL
CONTINUE WITH A TEMPO GROUP FOR CEILINGS IN THE 4000 FT RANGE THRU
14Z. IF SFC LOW STAY WEST OF DIA THEN THESE LOWER CEILINGS MAY NOT
AFFECT THE AIRPORT.
FOR TONIGHT GUSTY SSW WINDS SHOULD BECOME MORE WLY BY 02Z WITH
SOME GUSTS TO 25 MPH THRU 06Z POSSIBLE. IN FACT THESE GUSTY WINDS
COULD CONTINUE THRU FRI MORNING IF STRONGER WINDS NR THE
FOOTHILLS MIX DOWN TO THE SFC.
&&
.HYDROLOGY...NO ISSUES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
COZ035-036-038-039.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
FRIDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...RPK
LONG TERM....MEIER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
335 PM EDT THU OCT 10 2013
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER ENERGETIC UPPER
LEVEL PATTERN OVER THE CONUS. DEEP AND SHARP TROUGHING IS IN PLACE
OVER THE INTER-MOUNTAIN WEST WHICH IS ANCHORED BY A VIGOROUS UPPER
LOW NEAR THE 4-CORNERS REGION. QUITE A BIT OF LIGHTNING STILL
SHOWING UP WITHIN THE COLD POOL UNDER THE LOW...HIGHLIGHTING THE
STRENGTH OF THIS FEATURE. NORTHERN STREAM FLOW THEN RIDGES TO THE
NORTH THROUGH THE HIGH PLAINS INTO SOUTH-CENTRAL AND SOUTHEAST
CANADA. REMOVED FROM THIS FLOW IS A BROAD TROUGH ALONG THE EAST
COAST WITH AN UPPER LOW SPINNING OVER THE DELMARVA REGION. THIS
FEATURE AND AN ASSOCIATED SURFACE REFLECTION LOW WILL REMAIN IN
PLACE THROUGH THE NEXT COUPLE OF DAYS PROVIDING A WET AND DREARY
FORECAST TO THE MID-ATLANTIC STATES.
OUR POSITION BEHIND THIS TROUGH AXIS GIVES US A VERY DIFFERENT
FORECAST COMPARED TO THOSE AREAS FURTHER TO OUR NORTH. WV
IMAGERY SHOWS SIGNIFICANT SUPPRESSION/DRYING WORKING SOUTHWARD OVER
THE FLORIDA PENINSULA. IN FACT...THE GFS AND ECMWF CONTINUE SUGGEST
THE UPPER LEVEL Q-VECTOR DIVERGENCE WILL ONLY INCREASE WITH TIME
INTO TONIGHT OVER OUR FORECAST AREA. 10/12Z RAOBS ACROSS THE STATE
SHOWED A STEADY DECREASE IN PW VALUES FROM SOUTH TO NORTH WITH KMFL
AROUND 1.7"...KTBW...JUST OVER 1"...AND KJAX DOWN BELOW 1". THESE
VALUES ARE BELOW NORMAL...BUT NOT UNHEARD OF FOR MID OCTOBER.
HOWEVER...THE COMBINATION OF THE DRIER COLUMN...NO FOCUS
MECHANISM...AND THE OVERALL SUPPRESSION OF THE MID/UPPER TROP WILL
KEEP OUR FORECAST RAIN FREE THROUGH THE NEXT COUPLE OF DAYS.
&&
.SHORT TERM (TONIGHT THROUGH SATURDAY)...
TONIGHT...
SKIES BECOME CLEAR QUICKLY WITH THE SETTING OF THE SUN. THE DRY
ATMOSPHERE AND CLEAR SKIES WILL ALLOW FOR ANOTHER COMFORTABLY COOL
OCTOBER NIGHT INTO EARLY FRIDAY MORNING. LOW TEMPS BY SUNRISE SHOULD
REACH DOWN IN THE UPPER 50S/AROUND 60 NORTH OF TAMPA...AND IN THE
60S SOUTH OF THE I-4 CORRIDOR. SOME OF THE COOP MOS SITES ARE
SHOWING TEMPERATURES A BIT LOWER THAN WHAT IS CURRENTLY FORECAST.
ITS NOT IMPOSSIBLE TO SEE THESE LOWER VALUES...HOWEVER IN
GENERAL...UNLESS YOU ARE IN A NEAR IDEAL RADIATIONAL COOLING SETUP
(RESERVED MAINLY FOR WINTER HIGH PRESSURE)...THESE COOP VALUES ARE
OFTEN BIASED ON THE LOW SIDE.
FRIDAY/FRIDAY NIGHT...
THE COOL START TO THE MORNING WILL ONLY LEAD INTO YET ANOTHER MAINLY
SUNNY AND SEASONABLE DAY TO END OUT THE WORK WEEK. SURFACE HIGH
PRESSURE WILL HAVE BECOME ESTABLISHED OVER THE NORTHEAST GULF AND
NORTHERN HALF OF THE FL PENINSULA UNDERNEATH A DEEP LAYER NW FLOW ON
THE BACKSIDE OF THE EASTERN U.S. TROUGH. THIS NW FLOW WILL CONTINUE
TO DELIVER A DRY MID/UPPER LEVEL AIRMASS WITH A LEAST MODEST LEVELS
OF SYNOPTIC SUPPRESSION. AS MENTIONED ABOVE THIS WILL LEAD TO A
DRY...AND COMFORTABLE DAY WITH HIGH TEMPS RISING INTO THE 80S UNDER
MOSTLY CLEAR SKIES IN THE MORNING...AND A MIX OF SUN AND SHALLOW CU
FOR THE AFTERNOON. FRIDAY NIGHT MAY BE THE BEST CHANCE TO SEE A FEW
NORMALLY COLDER SPOTS UP OVER THE NATURE COAST REACH THE LOWER/MID
50S...DUE TO AN ALMOST NIL GRADIENT. ELSEWHERE IT WILL STILL BE ON
THE COOL SIDE (ESPECIALLY AFTER THE LONG SUMMER) WITH MANY INLAND
SPOTS IN THE UPPER 50S TO AROUND 60 AND COASTAL SPOTS IN THE 60S.
SATURDAY...MORE OF THE SAME. UPPER TROUGH PULLS A BIT FURTHER EAST
ALLOWING HEIGHT RISES TO BUILD OVER THE STATE FROM THE GULF OF
MEXICO AND NORTHERN GULF COAST. LOOKING LIKE A "CHAMBER OF COMMERCE"
TYPE OF DAY TO START OUT THE WEEKEND WITH PLENTY OF
SUNSHINE...SEASONABLE TEMPS...AND COMFORTABLE DEWPOINTS. NEAR ZERO
CHANCE OF RAIN FOR SATURDAY...SO TRY TO GET OUTSIDE AND ENJOY IT!
&&
.LONG TERM (SUNDAY - THURSDAY)...
MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH EARLY NEXT
WEEK...WITH SOLUTIONS THEN BEGINNING TO DIVERGE A BIT BY THE MIDDLE
AND END OF NEXT WEEK WITH RESPECT TO THE PROGRESSIVENESS OF THE NEXT
COLD FRONT. OVERALL...HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER
FEATURE THROUGH THE PERIOD...WITH THE POTENTIAL FOR A COLD FRONT TO
APPROACH THE REGION LATE NEXT WEEK. MAINLY DRY CONDITIONS ARE
EXPECTED...BUT SOME INCREASE IN DEEP LAYER MOISTURE MAY RESULT IN A
FEW ISOLATED SHOWERS NEXT WEDNESDAY AND THURSDAY. AS A RESULT...WILL
CARRY SLIGHT CHANCE POPS THESE DAYS...WITH RAIN FREE CONDITIONS
THROUGH THE REMAINDER OF THE LONG TERM PERIODS. TEMPERATURES ARE
EXPECTED TO RUN SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
FR...WITH OCNL BKN CIGS AOA 035 THROUGH THE AFTERNOON. VFR CONTINUES
THROUGH FRI ALTHOUGH THERE MAY BE LIMITED BR AND/OR LOW
CIGS....ESPECIALLY LAL AND PGD...LATE NIGHT. WINDS ARE IN THE
PROCESS OF SHIFTING TO ONSHORE AT COASTAL TERMINALS FOR THE
AFTERNOON. WINDS GO TO NE OR EAST AND DIMINISH SOME OVERNIGHT.
&&
.MARINE...
HIGH PRESSURE WILL BUILD OVER THE NORTHEAST GULF OF MEXICO THROUGH
THIS EVENING...AND THEN REMAIN IN PLACE THROUGH AT LEAST THE FIRST
HALF OF THE UPCOMING WEEKEND. NORTH OF THE WATERS AND REMAIN IN
PLACE THROUGH THE WEEKEND.
&&
.FIRE WEATHER...
HIGH PRESSURE BUILDS INTO NORTH FLORIDA TONIGHT AND REMAINS IN PLACE
THROUGH THE EARLY PORTION OF THE UPCOMING WEEKEND. ENOUGH DRY AIR
WILL BE IN PLACE TO RESULT RELATIVE HUMIDITY VALUES APPROACHING OR
BRIEFLY DROPPING BELOW CRITICAL LEVELS DURING BOTH FRIDAY AND
SATURDAY AFTERNOONS. THE GREATEST POTENTIAL FOR A BRIEF PERIOD WITH
RELATIVE HUMIDITY VALUES DROPPING BELOW 35 PERCENT WILL BE ALONG AND
NORTH OF THE I-4 CORRIDOR. HOWEVER...ERC VALUES AND DISPERSION
INDICES WILL BE WELL BELOW CRITICAL LEVELS AND NO SIGNIFICANT FIRE
WEATHER CONCERNS ARE ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 67 86 66 85 / 0 0 0 10
FMY 68 88 66 86 / 0 0 0 10
GIF 64 89 61 86 / 0 0 0 10
SRQ 68 85 65 84 / 0 0 0 10
BKV 58 86 56 86 / 0 0 0 10
SPG 71 85 69 85 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM...JELSEMA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1045 AM EDT THU OCT 10 2013
.UPDATE (REST OF TODAY THROUGH FRIDAY)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER ENERGETIC UPPER
LEVEL PATTERN OVER THE CONUS. DEEP AND SHARP TROUGHING IS IN PLACE
OVER THE INTER-MOUNTAIN WEST WHICH IS ANCHORED BY A VIGOROUS UPPER
LOW NEAR THE 4-CORNERS REGION. QUITE A BIT OF LIGHTNING SHOWING UP
WITHIN THE COLD POOL UNDER THE LOW...HIGHLIGHTING THE STRENGTH OF
THIS FEATURE. NORTHERN STREAM FLOW THEN RIDGES TO THE NORTH THROUGH
THE HIGH PLAINS INTO SOUTH-CENTRAL AND SOUTHEAST CANADA. REMOVED
FROM THIS FLOW IS A BROAD TROUGH ALONG THE EAST COAST WITH AN UPPER
LOW SPINNING OVER THE DELMARVA REGION. THIS FEATURE AND AN
ASSOCIATED SURFACE REFLECTION LOW WILL REMAIN IN PLACE THROUGH THE
NEXT COUPLE OF DAYS PROVIDING A WET AND DREARY FORECAST TO THE
MID-ATLANTIC STATES.
OUR POSITION BEHIND THIS TROUGH AXIS GIVES US A VERY DIFFERENT
FORECAST TO THOSE AREAS TO OUR NORTH. WV IMAGERY SHOWS SIGNIFICANT
SUPPRESSION/DRYING WORKING SOUTHWARD OVER THE FLORIDA PENINSULA. IN
FACT...THE GFS AND ECMWF SUGGEST THE UPPER LEVEL Q-VECTOR DIVERGENCE
WILL ONLY INCREASE WITH TIME INTO TONIGHT OVER OUR FORECAST AREA.
10/12Z RAOBS ACROSS THE STATE SHOWED A STEADY DECREASE IN PW VALUES
FROM SOUTH TO NORTH WITH KMFL AROUND 1.7"...KTBW...JUST OVER
1"...AND KJAX DOWN BELOW 1". THESE VALUES ARE BELOW NORMAL...BUT NOT
UNHEARD OF FOR MID OCTOBER. HOWEVER...THE COMBINATION OF THE DRIER
COLUMN...NO FOCUS MECHANISM...AND THE OVERALL SUPPRESSION OF THE
MID/UPPER TROP WILL KEEP OUR FORECAST RAIN FREE THROUGH THE NEXT
COUPLE OF DAYS.
BARELY A CLOUD IN THE SKY LATE THIS MORNING FOR MUCH OF THE FORECAST
AREA. SEEING A FEW LOWER LEVEL CLOUDS DOWN TOWARD FT. MYERS...BUT
OTHERWISE BRIGHT AND SUNNY FOR THE REST OF THE ZONES. WE DO SEE
SCT-BKN STRATOCU BEGINNING ABOUT 20 OR SO MILES OFFSHORE INTO THE
GULF. THESE LOWER CLOUDS ARE AN INSTABILITY RESPONSE TO THE COOL
MORNING LAND TEMPS BEING ADVECTED OUT OVER THE WARMER GULF
WATERS...A SURE SIGN THAT FALL IS BEGINNING TO ARRIVE. EARLY MORNING
LOW TEMPERATURES REACHED DOWN INTO THE UPPER 50S OVER PORTIONS OF
THE NATURE COAST WITH GENERALLY 60S ELSEWHERE.
REST OF TODAY...VERY LITTLE TO NO CHANCE OF RAIN THROUGH THE REST OF
THE DAY. TIME-HEIGHT PLOTS SHOW ENOUGH LOW LEVEL TRAPPED MOISTURE
UNDERNEATH THE UPPER LEVEL SUPPRESSION TO SUPPORT A SCT AND SHALLOW
CU FIELD FOR OUR SOUTHERN ZONES THROUGH THE AFTERNOON
HOURS...HOWEVER...BY THE TIME YOU GET TO TAMPA AND NORTHWARD...EVEN
MUCH OF THIS LOWER LEVEL MOISTURE HAS BEEN SCOURED OUT...AND WOULD
EXPECT A FEW CU AT BEST. WILL KEEP THE FORECAST MOSTLY SUNNY WITH
HIGH TEMP REACHING THE MIDDLE 80S BY 3-4PM.
SKIES BECOME CLEAR QUICKLY WITH THE SETTING OF THE SUN. THE DRY
ATMOSPHERE AND CLEAR SKIES WILL ALLOW FOR ANOTHER COMFORTABLY COOL
OCTOBER NIGHT INTO EARLY FRIDAY MORNING. LOW TEMPS BY SUNRISE SHOULD
REACH DOWN IN THE UPPER 50S/AROUND 60 NORTH OF TAMPA...AND IN THE
60S SOUTH OF THE I-4 CORRIDOR.
THE COOL START FRIDAY MORNING WILL ONLY LEAD INTO YET ANOTHER MAINLY
SUNNY AND SEASONABLE DAY TO END OUT THE WORK WEEK. ENJOY!
&&
.AVIATION...
LIMITED EARLY MORNING BR/LOW CIGS HAVE LIFTED. VFR THROUGH 11/12Z
WITH ONLY FEW-SCT AOA 035. NE WINDS BACK TO NORTH OR NW DURING THE
AFTERNOON AT COASTAL TERMINALS...AT 9 KT OR LESS.
&&
.MARINE...
HIGH PRESSURE WILL BUILD OVER THE NORTHEAST GULF OF MEXICO THROUGH
THIS EVENING...AND THEN REMAIN IN PLACE THROUGH AT LEAST THE FIRST
HALF OF THE UPCOMING WEEKEND. NORTH OF THE WATERS AND REMAIN IN
PLACE THROUGH THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 86 69 86 68 / 0 0 0 0
FMY 88 69 88 67 / 10 0 0 0
GIF 88 67 88 65 / 0 0 0 0
SRQ 85 68 86 66 / 0 0 0 0
BKV 87 56 87 55 / 0 0 0 0
SPG 84 73 86 70 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
106 PM CDT THU OCT 10 2013
.DISCUSSION...
322 AM CDT
TODAY THROUGH TONIGHT...
SIMILAR STORY FOR TODAY...ABUNDANT SUNSHINE AND UNSEASONABLE
WARMTH ACROSS THE REGION. BROAD ANTI-CYCLONIC FLOW REMAINS
ANCHORED ACROSS THE EASTERN THIRD OF THE CONUS...WITH A WAVE
LIFTING NORTHEAST OFF OF THE VIRGINIA COAST. NEAR CLOUDLESS SKIES
WITH LIGHT TO CALM WINDS EARLY THIS MORNING ACROSS THE FORECAST
AREA. VWP FROM WSR-88D KLOT INDICATE WINDS REMAIN RATHER UNIFORM
FROM THE EAST AT 1-9KFT AGL. LOCATIONS ADJACENT TO LAKE MICHIGAN
IN FAR NORTHEAST IL CONTINUE TO SEE TEMPS HOLDING IN THE LOW
50S...WHILE FURTHER SOUTH IN THE METRO CHICAGO AREA TEMPS HOVER IN
THE MID 50S. ELSEWHERE TEMPS HAVE RADIATED INTO THE LOW/MID
40S...WITH T/TD SPREADS NEARING 2 DEG OR LESS. THE COMBINATION OF
MINIMAL T/TD SPREADS AND CALM WINDS HAS ALLOWED PATCHY FOG TO
DEVELOP AGAIN THIS MORNING. EXPECT A FEW LOW LYING AREAS TO SEE
VSBYS REDUCED TO ARND 1SM...HOWEVER SHOULD ONLY LINGER UNTIL JUST
AFTER DAYBREAK. SHORTLY AFT SUNRISE THE SFC SHUD QUICKLY WARM
GIVEN THE PAST SEVERAL DAYS OF DRY CONDS. THIS HAS RESULTED IN
REDUCED HEAT CAPACITY...AND ATMOSPHERIC PARCELS WILL RESPOND TO
THE SOLAR RADIATION IN THE FORM OF A LARGE DIURNAL SWING IN TEMPS
TODAY. PLUMES SUGGEST TEMPS WILL BE IN THE MID/UPR 70S FOR MUCH OF
THE CWFA...WITH THE EXCEPTION OF AREAS ADJACENT TO LAKE MICHIGAN.
AN AFTN LAKE BREEZE IS EXPECTED TO DEVELOP AND PUSH INLAND...WHICH
WILL LIKELY CAP TEMPS DOWNTOWN CHICAGO IN THE UPR 60S.
TONIGHT DRY WEATHER CONTINUES WITH NEAR CLOUDLESS SKIES YET
AGAIN...A FEW CIRRUS CLOUDS MAY SLIDE OVERHEAD WHICH MAY SLOW THE
RATE OF COOLING TONIGHT. THUS IT APPEARS TEMPS WILL LIKELY BE
SLIGHTLY WARMER IN THE LOW 50S...WITH A FEW TRADITIONAL LOCATIONS
RADIATING INTO THE UPR 40S.
CONFIDENCE...HIGH.
FRIDAY THROUGH SATURDAY...
MID-LVL RIDGING CONTINUES TO HANG TOUGH THROUGH MUCH OF FRI...AS
THE STRENGTH OF THE 500MB RIDGE OVER QUEBEC/EASTERN ONTARIO REMAINS
PROGGED AT 3 SIGMA. GIVEN THE STRENGTH OF THE DOWNSTREAM RIDGE
THROUGH FRI NGT...IT APPEARS TO BE HAVING A SIGNIFICANT DIMINISHING
ROLE IN THE APPROACHING MID-LVL SHORTWAVE THAT WILL LIFT NORTHEAST
FROM THE FOUR-CORNERS REGION. OPERATIONAL GUIDANCE HAS CONTINUED TO
TREND DRIER WITH THIS SYSTEM...WITH THE EARLIEST PRECIP NOT ARRIVING
UNTIL ARND DAYBREAK SAT. LCL WRF MODEL THRU 12Z SAT INDICATES DRY
WEATHER WITH THE FRONTAL BOUNDARY MUCH FASTER AND NEARING FAR
NORTHWEST IL ARND DAYBREAK SAT. EC/GFS BOTH HAVE TRENDED DRIER WITH
THE EARLY WEEKEND SYSTEM...WITH THE BEST DYNAMICS PASSING WELL
NORTHWEST OF THE FORECAST AREA SAT. IT IS CONCEIVABLE THAT SAT MAY
JUST SEE SPOTTY SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM SOUTH
OF I-80...AS MUCAPE IN THE SFC-500MB LAYER HOVERS ARND 200-400J/KG.
THIS TOO HAS BEEN ON A DECREASING TREND.
AT THIS TIME HAVE HELD ONTO MENTION OF ISOLATED THUNDER FOR SAT THRU
SAT EVE...THEN WITH THE FORWARD SPEED INCREASING FOR SAT NGT HAVE
PULLED MENTION OF PRECIP AFT MIDNIGHT. FLOW THEN TURNS NORTHWEST
BEHIND THE BOUNDARY...WITH COOLER/DRIER AIR FILTERING INTO THE CWFA
FOR THE REMAINDER OF THE WEEKEND.
TEMPS FRI AHEAD OF THE SYSTEM WILL LIKELY BE WARM AGAIN...WITH
STRONG SOUTHEASTERLY TURNING SOUTHERLY FLOW. MANY PLUMES INDICATE
TEMPS WILL BE IN THE MID/UPR 70S FRI...AND COULD PERHAPS SEE A
HANDFUL OF POINTS REACH 80 DEGREES SOUTH OF A LASALLE TO KANKAKEE
LINE. THEN WITH INCREASED CLOUD COVER FRI NGT TEMPS WILL REMAIN MILD
IN THE MID/UPR 50S. DEPENDING ON THE TIMING OF FRONTAL PASSAGE
SAT...AND IF CLOUD COVER CAN ERODE QUICK ENOUGH BEFORE
SUNSET...TEMPS COULD STILL WARM INTO THE LOW/MID 70S. THE WARMEST
LOCATIONS WILL LIKELY BE THE SOUTHEAST CWFA WHERE TEMPS MAY TOUCH 80
DEG SAT AFTN.
CONFIDENCE...HIGH.
SUNDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE CONTINUED TO PROG SLOW WEAKENING IN THE 500MB RIDGE
OVER QUEBEC SUN...WITH THE TROUGH OVER THE CENTRAL CONUS FLATTENING.
AN ELONGATED TROUGH APPEARS TO SETUP SUN NGT STRETCHING SOUTHWEST
THROUGH THE ROCKIES...THEN RIDGING IS POISED TO DEVELOP ACROSS THE
PAC-NW MON INTO TUE. THE INCREASING MID-LVL HEIGHTS ACROSS THE
PAC-NW/WESTERN CANADA WILL PLAY A ROLE IN A POSSIBLE PATTERN
ADJUSTMENT TOWARDS THE MIDDLE OF NEXT WEEK.
OPERATIONAL GUIDANCE SLIDES SFC RIDGE INTO THE REGION SUN THRU
MON...THEN QUICKLY DRIFTS NORTHEAST MON NIGHT. OPERATIONAL GUIDANCE
HAS COME INTO BETTER AGREEMENT WITH A SHORTWAVE LIFTING INTO THE
CENTRAL PLAINS MON NGT...WITH CONSIDERABLE MOISTURE BEING PUMPED
INTO THIS FEATURE. GUIDANCE THEN BRINGS PRECIP NORTHEAST INTO THE
FORECAST AREA MON NGT/TUE. SOME UNCERTAINTY REMAINS WITH RESPECT TO
THE TIMING/COVERAGE OF PRECIP...HOWEVER CONCEPTUALLY THIS SYSTEM
WOULD LIKELY PRODUCE A DECENT SLUG OF PRECIP TUE BEFORE A DRY SLOT
PIVOTS EAST TUE NGT/WED.
THE OVERALL THEME WITH TEMPS IN THE EXTENDED PERIODS IS MORE OF A
SEASONAL SETUP...HOWEVER TEMPS COULD REMAIN MUCH COOLER IF ABUNDANT
PRECIP DOES DEVELOP. THIS COULD HOLD TEMPS IN THE MID/UPR 50S...AT
THIS POINT HAVE HELD ONTO TEMPS IN THE LOW/MID 60S.
THEN TOWARDS THE MIDDLE OF NEXT WEEK WITH THE AFOREMENTIONED RIDGING
ACROSS THE PAC-NW/WESTERN CANADA REMAINING IN PLACE...THIS WILL
LIKELY PROVIDE COOLER AIR TO SLIDE SOUTHEAST ACROSS CENTRAL CANADA
AND PUSH IN BEHIND THE EARLY WEEK SYSTEM INTO THE CWFA WED. HIGHS
WED MAY STRUGGLE TO WARM BEYOND THE MID 50S.
CONFIDENCE...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEAK LAKE BREEZE ALONG/JUST INLAND OF SHORE AT MIDDAY TO
CONTINUE TO MOVE INLAND AND PASS BY KMDW AND KORD DURING THE
EARLY TO MID AFTERNOON.
TRS
//DISCUSSION...UPDATED 18Z...
* WEAK PRESSURE GRADIENT TO REMAIN ACROSS THE REGION THROUGH
TONIGHT. CONTINUED SURFACE HEATING DESPITE SOME PATCHES OF
THICKER CIRRUS MOVING OVERHEAD WILL RESULT IN ADVANCEMENT OF A
WEAK LAKE BREEZE INLAND DURING THE AFTERNOON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...DRY/VFR.
* SATURDAY...CHANCE OF SHRA/SLIGHT CHANCE OF TSRA. COLD FRONT/WIND
SHIFT TO THE WEST BY EARLY AFTERNOON.
* SUNDAY AND MONDAY...DRY/VFR.
* TUESDAY AND WEDNESDAY...CHANCE OF SHRA.
&&
.MARINE...
106 PM CDT
LOW PRESSURE OVER THE CENTRAL HIGH PLAINS WILL RAPIDLY DEEPEN AS IT
LIFTS NORTH INTO THE NORTHERN PLAINS FRIDAY...THEN CONTINUES NORTH
TO HUDSON BAY OVER THE WEEKEND. THE STRONG LOW WILL RESULT IN
STRENGTHENING SOUTHERLY FLOW FRIDAY INTO FRIDAY NIGHT BEFORE
GRADIENT WEAKENS AS THE LOW LIFTS FARTHER NORTH AWAY FROM THE LAKE
THIS WEEKEND AND WINDS SHIFT TO THE WEST. PUSH OF COLD AIR BEHIND
THE SYSTEM IS WEAK AND HIGH PRESSURE WILL MOVE QUICKLY IN RESULTING
IN QUICKLY DIMINISHING WINDS/WAVES BEHIND THE FRONT. ANOTHER STRONG
LOW PRESSURE IS FORECAST TO DEVELOP OVER THE PLAINS EARLY NEXT WEEK
BEFORE MOVING INTO THE GREAT LAKES REGION TUESDAY. THERE ARE STILL
DIFFERENCES IN THE MODELS WITH RESPECT TO INTENSITY AND TRACK...BUT
GROWING CONSENSUS WOULD SEEM TO SUPPORT INCREASING WINDS AND
BUILDING WAVES BY TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1246 PM CDT Thu Oct 10 2013
.DISCUSSION...
ISSUED 1038 AM CDT Thu Oct 10 2013
High pressure ridge extending back from the eastern Great Lakes
into the Midwest this morning. Very few clouds associated with a
small stretch of moisture creeping into the llvls. Other than a
few clouds...not much in the way of weather to speak of in the
short term. Somewhat variable and light winds in the absence of a
strong gradient...though south-southwesterly is the predominant
direction. Forecast on track, but will update the grids for a
quicker diurnal warm up this morning, and send update to eliminate
the morning fog wording in the southern tier.
&&
.AVIATION...
ISSUED 1241 PM CDT Thu Oct 10 2013
Increased RH at and below 850mb resulting in a cloud deck this
afternoon around 4kft. Diurnal enhancement...so expect a slight
lift and sct out before sunset...and a lowering when the inversion
sets up tonight. Some vis reduction possible in DEC closer to the
richer boundary layer moisture in the SE. Hesitate to go too far
north with the BR mention for now. Bringing back the BKN deck mid
morning. Light south/southeasterly flow through today and the
overnight. VFR for much of the forecast with a tempo drop to MVFR
vis toward dawn.
HJS
&&
.PREV DISCUSSION...
ISSUED 305 AM CDT Thu Oct 10 2013
SHORT TERM...Today through Saturday
Gradual moisture advection from the south over the past 24 hours
has resulted in 50+ surface dewpoints spreading northward into
southern Illinois early this morning. Due to the increased low-level
moisture and nearly calm winds beneath ridge axis, areas of fog
are beginning to develop south of I-70. HRRR shows the fog
developing/spreading further north toward dawn. Have therefore
included patchy fog along and south of a Jacksonville to Paris
line through 14z/9am. Once early morning fog dissipates, partly to
mostly sunny skies and very warm conditions will prevail for the
remainder of the day. Afternoon high temperatures will be a degree
or two warmer than yesterday, with readings reaching the middle to
upper 70s.
As ridge only slowly shifts eastward, the potential exists for
more patchy fog tonight. Given increasing moisture, clear skies,
and continued light winds near the departing ridge axis, will
include fog mention for the eastern half of the KILX CWA. Further
west, light return flow should keep atmosphere mixed just enough
to prevent fog west of I-55. Once fog dissipates, another mostly
sunny and warm day will unfold on Friday...with highs reaching the
80-degree mark.
00z Oct 10 models have sped up the approach of the weekend system,
with FROPA now expected to occur Saturday afternoon. NAM is the
fastest of the models, but think it is too aggressive with pushing
the front eastward into the prevailing upper ridge. Will therefore
trend closer to the slightly slower ECMWF/GFS solution. With front
expected to be along the Mississippi River by 12z Saturday, will
maintain low chance POPs in the Illinois River Valley late Friday
night, then will spread rain chances further east across the
rest of the area on Saturday. With best upper support remaining
well to the N/NW and only a shallow moisture profile in place, am
not expecting a widespread soaking rainfall on Saturday. Will keep
POPs in the chance category accordingly. Since system is moving a
bit faster than previously forecast, will only hold on to chance
POPs across the eastern CWA into the evening hours, then will go
dry across the board overnight.
LONG TERM...Sunday through Wednesday
High pressure will build into the region behind the departing cold
front on Sunday, with models indicating a very dry airmass with
dewpoints in the lower to middle 40s settling in. Mostly clear and
dry weather is expected for both Sunday and Monday, with warm
afternoon highs in the upper 60s/lower 70s and cool overnight lows
in the 40s.
Next system is still slated to come into the picture early next
week, although details are not clear at this point. An upper-level
trough is expected to dig into the Rockies Sunday into Monday,
although how deep the system becomes and how quickly it lifts
northeastward are still very much in question. GFS is more
progressive with the system, with the upper low and its associated
surface wave ejecting into the western Great Lakes by Tuesday
evening. Meanwhile, latest ECMWF is deeper and holds the system
back in the Rockies/Plains until Thursday. Given significant
timing discrepancies, have opted to leave going forecast alone
until better agreement is achieved. As such, am expecting showers
and thunderstorms to develop across the area Monday night into
Tuesday, followed by cooler/drier weather by Wednesday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1218 PM CDT THU OCT 10 2013
.DISCUSSION...
322 AM CDT
TODAY THROUGH TONIGHT...
SIMILAR STORY FOR TODAY...ABUNDANT SUNSHINE AND UNSEASONABLE
WARMTH ACROSS THE REGION. BROAD ANTI-CYCLONIC FLOW REMAINS
ANCHORED ACROSS THE EASTERN THIRD OF THE CONUS...WITH A WAVE
LIFTING NORTHEAST OFF OF THE VIRGINIA COAST. NEAR CLOUDLESS SKIES
WITH LIGHT TO CALM WINDS EARLY THIS MORNING ACROSS THE FORECAST
AREA. VWP FROM WSR-88D KLOT INDICATE WINDS REMAIN RATHER UNIFORM
FROM THE EAST AT 1-9KFT AGL. LOCATIONS ADJACENT TO LAKE MICHIGAN
IN FAR NORTHEAST IL CONTINUE TO SEE TEMPS HOLDING IN THE LOW
50S...WHILE FURTHER SOUTH IN THE METRO CHICAGO AREA TEMPS HOVER IN
THE MID 50S. ELSEWHERE TEMPS HAVE RADIATED INTO THE LOW/MID
40S...WITH T/TD SPREADS NEARING 2 DEG OR LESS. THE COMBINATION OF
MINIMAL T/TD SPREADS AND CALM WINDS HAS ALLOWED PATCHY FOG TO
DEVELOP AGAIN THIS MORNING. EXPECT A FEW LOW LYING AREAS TO SEE
VSBYS REDUCED TO ARND 1SM...HOWEVER SHOULD ONLY LINGER UNTIL JUST
AFTER DAYBREAK. SHORTLY AFT SUNRISE THE SFC SHUD QUICKLY WARM
GIVEN THE PAST SEVERAL DAYS OF DRY CONDS. THIS HAS RESULTED IN
REDUCED HEAT CAPACITY...AND ATMOSPHERIC PARCELS WILL RESPOND TO
THE SOLAR RADIATION IN THE FORM OF A LARGE DIURNAL SWING IN TEMPS
TODAY. PLUMES SUGGEST TEMPS WILL BE IN THE MID/UPR 70S FOR MUCH OF
THE CWFA...WITH THE EXCEPTION OF AREAS ADJACENT TO LAKE MICHIGAN.
AN AFTN LAKE BREEZE IS EXPECTED TO DEVELOP AND PUSH INLAND...WHICH
WILL LIKELY CAP TEMPS DOWNTOWN CHICAGO IN THE UPR 60S.
TONIGHT DRY WEATHER CONTINUES WITH NEAR CLOUDLESS SKIES YET
AGAIN...A FEW CIRRUS CLOUDS MAY SLIDE OVERHEAD WHICH MAY SLOW THE
RATE OF COOLING TONIGHT. THUS IT APPEARS TEMPS WILL LIKELY BE
SLIGHTLY WARMER IN THE LOW 50S...WITH A FEW TRADITIONAL LOCATIONS
RADIATING INTO THE UPR 40S.
CONFIDENCE...HIGH.
FRIDAY THROUGH SATURDAY...
MID-LVL RIDGING CONTINUES TO HANG TOUGH THROUGH MUCH OF FRI...AS
THE STRENGTH OF THE 500MB RIDGE OVER QUEBEC/EASTERN ONTARIO REMAINS
PROGGED AT 3 SIGMA. GIVEN THE STRENGTH OF THE DOWNSTREAM RIDGE
THROUGH FRI NGT...IT APPEARS TO BE HAVING A SIGNIFICANT DIMINISHING
ROLE IN THE APPROACHING MID-LVL SHORTWAVE THAT WILL LIFT NORTHEAST
FROM THE FOUR-CORNERS REGION. OPERATIONAL GUIDANCE HAS CONTINUED TO
TREND DRIER WITH THIS SYSTEM...WITH THE EARLIEST PRECIP NOT ARRIVING
UNTIL ARND DAYBREAK SAT. LCL WRF MODEL THRU 12Z SAT INDICATES DRY
WEATHER WITH THE FRONTAL BOUNDARY MUCH FASTER AND NEARING FAR
NORTHWEST IL ARND DAYBREAK SAT. EC/GFS BOTH HAVE TRENDED DRIER WITH
THE EARLY WEEKEND SYSTEM...WITH THE BEST DYNAMICS PASSING WELL
NORTHWEST OF THE FORECAST AREA SAT. IT IS CONCEIVABLE THAT SAT MAY
JUST SEE SPOTTY SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM SOUTH
OF I-80...AS MUCAPE IN THE SFC-500MB LAYER HOVERS ARND 200-400J/KG.
THIS TOO HAS BEEN ON A DECREASING TREND.
AT THIS TIME HAVE HELD ONTO MENTION OF ISOLATED THUNDER FOR SAT THRU
SAT EVE...THEN WITH THE FORWARD SPEED INCREASING FOR SAT NGT HAVE
PULLED MENTION OF PRECIP AFT MIDNIGHT. FLOW THEN TURNS NORTHWEST
BEHIND THE BOUNDARY...WITH COOLER/DRIER AIR FILTERING INTO THE CWFA
FOR THE REMAINDER OF THE WEEKEND.
TEMPS FRI AHEAD OF THE SYSTEM WILL LIKELY BE WARM AGAIN...WITH
STRONG SOUTHEASTERLY TURNING SOUTHERLY FLOW. MANY PLUMES INDICATE
TEMPS WILL BE IN THE MID/UPR 70S FRI...AND COULD PERHAPS SEE A
HANDFUL OF POINTS REACH 80 DEGREES SOUTH OF A LASALLE TO KANKAKEE
LINE. THEN WITH INCREASED CLOUD COVER FRI NGT TEMPS WILL REMAIN MILD
IN THE MID/UPR 50S. DEPENDING ON THE TIMING OF FRONTAL PASSAGE
SAT...AND IF CLOUD COVER CAN ERODE QUICK ENOUGH BEFORE
SUNSET...TEMPS COULD STILL WARM INTO THE LOW/MID 70S. THE WARMEST
LOCATIONS WILL LIKELY BE THE SOUTHEAST CWFA WHERE TEMPS MAY TOUCH 80
DEG SAT AFTN.
CONFIDENCE...HIGH.
SUNDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE CONTINUED TO PROG SLOW WEAKENING IN THE 500MB RIDGE
OVER QUEBEC SUN...WITH THE TROUGH OVER THE CENTRAL CONUS FLATTENING.
AN ELONGATED TROUGH APPEARS TO SETUP SUN NGT STRETCHING SOUTHWEST
THROUGH THE ROCKIES...THEN RIDGING IS POISED TO DEVELOP ACROSS THE
PAC-NW MON INTO TUE. THE INCREASING MID-LVL HEIGHTS ACROSS THE
PAC-NW/WESTERN CANADA WILL PLAY A ROLE IN A POSSIBLE PATTERN
ADJUSTMENT TOWARDS THE MIDDLE OF NEXT WEEK.
OPERATIONAL GUIDANCE SLIDES SFC RIDGE INTO THE REGION SUN THRU
MON...THEN QUICKLY DRIFTS NORTHEAST MON NIGHT. OPERATIONAL GUIDANCE
HAS COME INTO BETTER AGREEMENT WITH A SHORTWAVE LIFTING INTO THE
CENTRAL PLAINS MON NGT...WITH CONSIDERABLE MOISTURE BEING PUMPED
INTO THIS FEATURE. GUIDANCE THEN BRINGS PRECIP NORTHEAST INTO THE
FORECAST AREA MON NGT/TUE. SOME UNCERTAINTY REMAINS WITH RESPECT TO
THE TIMING/COVERAGE OF PRECIP...HOWEVER CONCEPTUALLY THIS SYSTEM
WOULD LIKELY PRODUCE A DECENT SLUG OF PRECIP TUE BEFORE A DRY SLOT
PIVOTS EAST TUE NGT/WED.
THE OVERALL THEME WITH TEMPS IN THE EXTENDED PERIODS IS MORE OF A
SEASONAL SETUP...HOWEVER TEMPS COULD REMAIN MUCH COOLER IF ABUNDANT
PRECIP DOES DEVELOP. THIS COULD HOLD TEMPS IN THE MID/UPR 50S...AT
THIS POINT HAVE HELD ONTO TEMPS IN THE LOW/MID 60S.
THEN TOWARDS THE MIDDLE OF NEXT WEEK WITH THE AFOREMENTIONED RIDGING
ACROSS THE PAC-NW/WESTERN CANADA REMAINING IN PLACE...THIS WILL
LIKELY PROVIDE COOLER AIR TO SLIDE SOUTHEAST ACROSS CENTRAL CANADA
AND PUSH IN BEHIND THE EARLY WEEK SYSTEM INTO THE CWFA WED. HIGHS
WED MAY STRUGGLE TO WARM BEYOND THE MID 50S.
CONFIDENCE...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEAK LAKE BREEZE ALONG/JUST INLAND OF SHORE AT MIDDAY TO
CONTINUE TO MOVE INLAND AND PASS BY KMDW AND KORD DURING THE
EARLY TO MID AFTERNOON.
TRS
//DISCUSSION...UPDATED 18Z...
* WEAK PRESSURE GRADIENT TO REMAIN ACROSS THE REGION THROUGH
TONIGHT. CONTINUED SURFACE HEATING DESPITE SOME PATCHES OF
THICKER CIRRUS MOVING OVERHEAD WILL RESULT IN ADVANCEMENT OF A
WEAK LAKE BREEZE INLAND DURING THE AFTERNOON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...DRY/VFR.
* SATURDAY...CHANCE OF SHRA/SLIGHT CHANCE OF TSRA. COLD FRONT/WIND
SHIFT TO THE WEST BY EARLY AFTERNOON.
* SUNDAY AND MONDAY...DRY/VFR.
* TUESDAY AND WEDNESDAY...CHANCE OF SHRA.
&&
.MARINE...
300 AM...A LARGE RIDGE OF HIGH PRESSURE EXTENDING FROM THE WESTERN
LAKES TO NEW ENGLAND WILL SLOWLY DRIFT SOUTHEAST TONIGHT AND FRIDAY
AND EVENTUALLY MERGE WITH STRONGER HIGH PRESSURE MOVING SOUTHEAST
ACROSS QUEBEC FRIDAY AND FRIDAY NIGHT. THIS WILL MAINTAIN MAINLY
SOUTHEASTERLY FLOW OVER THE LAKE INTO FRIDAY WITH SPEEDS GRADUALLY
INCREASING INTO THE 10-20 KT RANGE FRIDAY. WEAK LOW PRESSURE NEAR
COLORADO THIS MORNING WILL DEEPEN AS IT MOVES NORTH ACROSS THE
DAKOTAS FRIDAY AND ACROSS MANITOBA AND WESTERN ONTARIO FRIDAY
NIGHT. THIS WILL CAUSE THE GRADIENT TO TIGHTEN ACROSS THE WESTERN
LAKES FRIDAY NIGHT INTO SATURDAY MORNING WITH A PERIOD OF 20-25KTS
POSSIBLE. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE SATURDAY
AFTERNOON OR SATURDAY EVENING SHIFTING WINDS TO THE WEST AND THEN
TO THE NORTHWEST SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE LAKES REGION SUNDAY INTO SUNDAY
NIGHT. ANOTHER LOW PRESSURE IS EXPECTED TO MOVE FROM THE CENTRAL
PLAINS MONDAY ACROSS THE LAKES REGION TUESDAY INTO WEDNESDAY...
THOUGH CONFIDENCE REGARDING THE STRENGTH AND TRACK OF THIS SYSTEM
REMAINS LOW AT THIS TIME. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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TIMELY DELIVERY OF DATA AND PRODUCTS BUT EVEN THESE SOURCES
CANNOT BE GUARANTEED DUE TO THE NATURE OF THE INTERNET.
Area Forecast Discussion
National Weather Service Lincoln IL
1042 AM CDT Thu Oct 10 2013
.DISCUSSION...
ISSUED 1038 AM CDT Thu Oct 10 2013
High pressure ridge extending back from the eastern Great Lakes
into the Midwest this morning. Very few clouds associated with a
small stretch of moisture creeping into the llvls. Other than a
few clouds...not much in the way of weather to speak of in the
short term. Somewhat variable and light winds in the absence of a
strong gradient...though south-southwesterly is the predominant
direction. Forecast on track, but will update the grids for a
quicker diurnal warm up this morning, and send update to eliminate
the morning fog wording in the southern tier.
HJS
&&
.AVIATION...
ISSUED 629 AM CDT Thu Oct 10 2013
VFR conditions will continue next 24hrs at all TAF sites. Lower
level moisture streaming up into the area currently and will
continue through the day and into tonight. Sct to broken clouds
around 4kft being reported in the obs and satellite shows this as
well. Based on satellite loop and obs, will have broken cigs at
all sites except for PIA during the day. Then all sites will
scatter out for this evening with scattered clouds continuing
overnight tonight. Winds will be southerly to southeasterly
through the whole period. Winds speeds strongest during the day at
7-8kts but then decrease some after sunset.
Auten
&&
.PREV DISCUSSION...
ISSUED 305 AM CDT Thu Oct 10 2013
SHORT TERM...Today through Saturday
Gradual moisture advection from the south over the past 24 hours
has resulted in 50+ surface dewpoints spreading northward into
southern Illinois early this morning. Due to the increased low-level
moisture and nearly calm winds beneath ridge axis, areas of fog
are beginning to develop south of I-70. HRRR shows the fog
developing/spreading further north toward dawn. Have therefore
included patchy fog along and south of a Jacksonville to Paris
line through 14z/9am. Once early morning fog dissipates, partly to
mostly sunny skies and very warm conditions will prevail for the
remainder of the day. Afternoon high temperatures will be a degree
or two warmer than yesterday, with readings reaching the middle to
upper 70s.
As ridge only slowly shifts eastward, the potential exists for
more patchy fog tonight. Given increasing moisture, clear skies,
and continued light winds near the departing ridge axis, will
include fog mention for the eastern half of the KILX CWA. Further
west, light return flow should keep atmosphere mixed just enough
to prevent fog west of I-55. Once fog dissipates, another mostly
sunny and warm day will unfold on Friday...with highs reaching the
80-degree mark.
00z Oct 10 models have sped up the approach of the weekend system,
with FROPA now expected to occur Saturday afternoon. NAM is the
fastest of the models, but think it is too aggressive with pushing
the front eastward into the prevailing upper ridge. Will therefore
trend closer to the slightly slower ECMWF/GFS solution. With front
expected to be along the Mississippi River by 12z Saturday, will
maintain low chance POPs in the Illinois River Valley late Friday
night, then will spread rain chances further east across the
rest of the area on Saturday. With best upper support remaining
well to the N/NW and only a shallow moisture profile in place, am
not expecting a widespread soaking rainfall on Saturday. Will keep
POPs in the chance category accordingly. Since system is moving a
bit faster than previously forecast, will only hold on to chance
POPs across the eastern CWA into the evening hours, then will go
dry across the board overnight.
LONG TERM...Sunday through Wednesday
High pressure will build into the region behind the departing cold
front on Sunday, with models indicating a very dry airmass with
dewpoints in the lower to middle 40s settling in. Mostly clear and
dry weather is expected for both Sunday and Monday, with warm
afternoon highs in the upper 60s/lower 70s and cool overnight lows
in the 40s.
Next system is still slated to come into the picture early next
week, although details are not clear at this point. An upper-level
trough is expected to dig into the Rockies Sunday into Monday,
although how deep the system becomes and how quickly it lifts
northeastward are still very much in question. GFS is more
progressive with the system, with the upper low and its associated
surface wave ejecting into the western Great Lakes by Tuesday
evening. Meanwhile, latest ECMWF is deeper and holds the system
back in the Rockies/Plains until Thursday. Given significant
timing discrepancies, have opted to leave going forecast alone
until better agreement is achieved. As such, am expecting showers
and thunderstorms to develop across the area Monday night into
Tuesday, followed by cooler/drier weather by Wednesday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
648 AM CDT THU OCT 10 2013
.DISCUSSION...
322 AM CDT
TODAY THROUGH TONIGHT...
SIMILAR STORY FOR TODAY...ABUNDANT SUNSHINE AND UNSEASONABLE
WARMTH ACROSS THE REGION. BROAD ANTI-CYCLONIC FLOW REMAINS
ANCHORED ACROSS THE EASTERN THIRD OF THE CONUS...WITH A WAVE
LIFTING NORTHEAST OFF OF THE VIRGINIA COAST. NEAR CLOUDLESS SKIES
WITH LIGHT TO CALM WINDS EARLY THIS MORNING ACROSS THE FORECAST
AREA. VWP FROM WSR-88D KLOT INDICATE WINDS REMAIN RATHER UNIFORM
FROM THE EAST AT 1-9KFT AGL. LOCATIONS ADJACENT TO LAKE MICHIGAN
IN FAR NORTHEAST IL CONTINUE TO SEE TEMPS HOLDING IN THE LOW
50S...WHILE FURTHER SOUTH IN THE METRO CHICAGO AREA TEMPS HOVER IN
THE MID 50S. ELSEWHERE TEMPS HAVE RADIATED INTO THE LOW/MID
40S...WITH T/TD SPREADS NEARING 2 DEG OR LESS. THE COMBINATION OF
MINIMAL T/TD SPREADS AND CALM WINDS HAS ALLOWED PATCHY FOG TO
DEVELOP AGAIN THIS MORNING. EXPECT A FEW LOW LYING AREAS TO SEE
VSBYS REDUCED TO ARND 1SM...HOWEVER SHOULD ONLY LINGER UNTIL JUST
AFTER DAYBREAK. SHORTLY AFT SUNRISE THE SFC SHUD QUICKLY WARM
GIVEN THE PAST SEVERAL DAYS OF DRY CONDS. THIS HAS RESULTED IN
REDUCED HEAT CAPACITY...AND ATMOSPHERIC PARCELS WILL RESPOND TO
THE SOLAR RADIATION IN THE FORM OF A LARGE DIURNAL SWING IN TEMPS
TODAY. PLUMES SUGGEST TEMPS WILL BE IN THE MID/UPR 70S FOR MUCH OF
THE CWFA...WITH THE EXCEPTION OF AREAS ADJACENT TO LAKE MICHIGAN.
AN AFTN LAKE BREEZE IS EXPECTED TO DEVELOP AND PUSH INLAND...WHICH
WILL LIKELY CAP TEMPS DOWNTOWN CHICAGO IN THE UPR 60S.
TONIGHT DRY WEATHER CONTINUES WITH NEAR CLOUDLESS SKIES YET
AGAIN...A FEW CIRRUS CLOUDS MAY SLIDE OVERHEAD WHICH MAY SLOW THE
RATE OF COOLING TONIGHT. THUS IT APPEARS TEMPS WILL LIKELY BE
SLIGHTLY WARMER IN THE LOW 50S...WITH A FEW TRADITIONAL LOCATIONS
RADIATING INTO THE UPR 40S.
CONFIDENCE...HIGH.
FRIDAY THROUGH SATURDAY...
MID-LVL RIDGING CONTINUES TO HANG TOUGH THROUGH MUCH OF FRI...AS
THE STRENGTH OF THE 500MB RIDGE OVER QUEBEC/EASTERN ONTARIO REMAINS
PROGGED AT 3 SIGMA. GIVEN THE STRENGTH OF THE DOWNSTREAM RIDGE
THROUGH FRI NGT...IT APPEARS TO BE HAVING A SIGNIFICANT DIMINISHING
ROLE IN THE APPROACHING MID-LVL SHORTWAVE THAT WILL LIFT NORTHEAST
FROM THE FOUR-CORNERS REGION. OPERATIONAL GUIDANCE HAS CONTINUED TO
TREND DRIER WITH THIS SYSTEM...WITH THE EARLIEST PRECIP NOT ARRIVING
UNTIL ARND DAYBREAK SAT. LCL WRF MODEL THRU 12Z SAT INDICATES DRY
WEATHER WITH THE FRONTAL BOUNDARY MUCH FASTER AND NEARING FAR
NORTHWEST IL ARND DAYBREAK SAT. EC/GFS BOTH HAVE TRENDED DRIER WITH
THE EARLY WEEKEND SYSTEM...WITH THE BEST DYNAMICS PASSING WELL
NORTHWEST OF THE FORECAST AREA SAT. IT IS CONCEIVABLE THAT SAT MAY
JUST SEE SPOTTY SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM SOUTH
OF I-80...AS MUCAPE IN THE SFC-500MB LAYER HOVERS ARND 200-400J/KG.
THIS TOO HAS BEEN ON A DECREASING TREND.
AT THIS TIME HAVE HELD ONTO MENTION OF ISOLATED THUNDER FOR SAT THRU
SAT EVE...THEN WITH THE FORWARD SPEED INCREASING FOR SAT NGT HAVE
PULLED MENTION OF PRECIP AFT MIDNIGHT. FLOW THEN TURNS NORTHWEST
BEHIND THE BOUNDARY...WITH COOLER/DRIER AIR FILTERING INTO THE CWFA
FOR THE REMAINDER OF THE WEEKEND.
TEMPS FRI AHEAD OF THE SYSTEM WILL LIKELY BE WARM AGAIN...WITH
STRONG SOUTHEASTERLY TURNING SOUTHERLY FLOW. MANY PLUMES INDICATE
TEMPS WILL BE IN THE MID/UPR 70S FRI...AND COULD PERHAPS SEE A
HANDFUL OF POINTS REACH 80 DEGREES SOUTH OF A LASALLE TO KANKAKEE
LINE. THEN WITH INCREASED CLOUD COVER FRI NGT TEMPS WILL REMAIN MILD
IN THE MID/UPR 50S. DEPENDING ON THE TIMING OF FRONTAL PASSAGE
SAT...AND IF CLOUD COVER CAN ERODE QUICK ENOUGH BEFORE
SUNSET...TEMPS COULD STILL WARM INTO THE LOW/MID 70S. THE WARMEST
LOCATIONS WILL LIKELY BE THE SOUTHEAST CWFA WHERE TEMPS MAY TOUCH 80
DEG SAT AFTN.
CONFIDENCE...HIGH.
SUNDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE CONTINUED TO PROG SLOW WEAKENING IN THE 500MB RIDGE
OVER QUEBEC SUN...WITH THE TROUGH OVER THE CENTRAL CONUS FLATTENING.
AN ELONGATED TROUGH APPEARS TO SETUP SUN NGT STRETCHING SOUTHWEST
THROUGH THE ROCKIES...THEN RIDGING IS POISED TO DEVELOP ACROSS THE
PAC-NW MON INTO TUE. THE INCREASING MID-LVL HEIGHTS ACROSS THE
PAC-NW/WESTERN CANADA WILL PLAY A ROLE IN A POSSIBLE PATTERN
ADJUSTMENT TOWARDS THE MIDDLE OF NEXT WEEK.
OPERATIONAL GUIDANCE SLIDES SFC RIDGE INTO THE REGION SUN THRU
MON...THEN QUICKLY DRIFTS NORTHEAST MON NIGHT. OPERATIONAL GUIDANCE
HAS COME INTO BETTER AGREEMENT WITH A SHORTWAVE LIFTING INTO THE
CENTRAL PLAINS MON NGT...WITH CONSIDERABLE MOISTURE BEING PUMPED
INTO THIS FEATURE. GUIDANCE THEN BRINGS PRECIP NORTHEAST INTO THE
FORECAST AREA MON NGT/TUE. SOME UNCERTAINTY REMAINS WITH RESPECT TO
THE TIMING/COVERAGE OF PRECIP...HOWEVER CONCEPTUALLY THIS SYSTEM
WOULD LIKELY PRODUCE A DECENT SLUG OF PRECIP TUE BEFORE A DRY SLOT
PIVOTS EAST TUE NGT/WED.
THE OVERALL THEME WITH TEMPS IN THE EXTENDED PERIODS IS MORE OF A
SEASONAL SETUP...HOWEVER TEMPS COULD REMAIN MUCH COOLER IF ABUNDANT
PRECIP DOES DEVELOP. THIS COULD HOLD TEMPS IN THE MID/UPR 50S...AT
THIS POINT HAVE HELD ONTO TEMPS IN THE LOW/MID 60S.
THEN TOWARDS THE MIDDLE OF NEXT WEEK WITH THE AFOREMENTIONED RIDGING
ACROSS THE PAC-NW/WESTERN CANADA REMAINING IN PLACE...THIS WILL
LIKELY PROVIDE COOLER AIR TO SLIDE SOUTHEAST ACROSS CENTRAL CANADA
AND PUSH IN BEHIND THE EARLY WEEK SYSTEM INTO THE CWFA WED. HIGHS
WED MAY STRUGGLE TO WARM BEYOND THE MID 50S.
CONFIDENCE...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LAKE BREEZE THIS AFTERNOON. CMS
//DISCUSSION...UPDATED 12Z...
A RIDGE OF HIGH PRESSURE EXTENDS OVER THE GREAT LAKES REGION THIS
MORNING AND WILL VERY SLOWLY DRIFT EAST TONIGHT AND FRIDAY. CALM
WINDS TO START WILL BECOME SOUTHEASTERLY UNDER 10KTS THIS MORNING.
THIS HIGH WILL ALSO ALLOW A LAKE BREEZE TO FORM WITH WINDS TURNING
EASTERLY AT ORD/MDW BY MID AFTERNOON...NORTHEASTERLY AT GYY. WINDS
WILL THEN SETTLE BACK TO LIGHT SOUTHEASTERLY AFTER SUNSET.
HIGH CLOUDS WILL SPREAD ACROSS THE REGION THIS MORNING AND A
4-5KFT STRATOCU DECK HAS DEVELOPED ACROSS SOUTH CENTRAL IL. THIS
MOISTURE WILL LIKELY CREEP NORTH THROUGH THE DAY AND SOME CU ARE
POSSIBLE THIS AFTERNOON.
FOG HAS BEEN QUITE VARIABLE EARLY THIS MORNING DUE TO ITS SHALLOW
NATURE. SOME MVFR VIS IS STILL POSSIBLE FOR A FEW HOURS AT
RFD/DPA...OTHERWISE VFR EXPECTED INTO THIS EVENING. WITH A BIT
MORE LOW LEVEL MOISTURE TONIGHT...EXPECT SIMILAR CONDITIONS WITH
LIGHT/SHALLOW FOG DEVELOPING IN SOME AREAS AFTER MIDNIGHT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH FOR A LAKE BREEZE REACHING ORD/MDW...MEDIUM FOR TIMING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...DRY/VFR.
* SATURDAY...CHANCE OF SHRA/SLIGHT CHANCE OF TSRA. COLD FRONT/WIND
SHIFT TO THE WEST BY EARLY AFTERNOON.
* SUNDAY AND MONDAY...DRY/VFR.
* TUESDAY AND WEDNESDAY...CHANCE OF SHRA.
&&
.MARINE...
300 AM...A LARGE RIDGE OF HIGH PRESSURE EXTENDING FROM THE WESTERN
LAKES TO NEW ENGLAND WILL SLOWLY DRIFT SOUTHEAST TONIGHT AND FRIDAY
AND EVENTUALLY MERGE WITH STRONGER HIGH PRESSURE MOVING SOUTHEAST
ACROSS QUEBEC FRIDAY AND FRIDAY NIGHT. THIS WILL MAINTAIN MAINLY
SOUTHEASTERLY FLOW OVER THE LAKE INTO FRIDAY WITH SPEEDS GRADUALLY
INCREASING INTO THE 10-20 KT RANGE FRIDAY. WEAK LOW PRESSURE NEAR
COLORADO THIS MORNING WILL DEEPEN AS IT MOVES NORTH ACROSS THE
DAKOTAS FRIDAY AND ACROSS MANITOBA AND WESTERN ONTARIO FRIDAY
NIGHT. THIS WILL CAUSE THE GRADIENT TO TIGHTEN ACROSS THE WESTERN
LAKES FRIDAY NIGHT INTO SATURDAY MORNING WITH A PERIOD OF 20-25KTS
POSSIBLE. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE SATURDAY
AFTERNOON OR SATURDAY EVENING SHIFTING WINDS TO THE WEST AND THEN
TO THE NORTHWEST SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE LAKES REGION SUNDAY INTO SUNDAY
NIGHT. ANOTHER LOW PRESSURE IS EXPECTED TO MOVE FROM THE CENTRAL
PLAINS MONDAY ACROSS THE LAKES REGION TUESDAY INTO WEDNESDAY...
THOUGH CONFIDENCE REGARDING THE STRENGTH AND TRACK OF THIS SYSTEM
REMAINS LOW AT THIS TIME. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
629 AM CDT Thu Oct 10 2013
.DISCUSSION...
ISSUED 305 AM CDT Thu Oct 10 2013
SHORT TERM...Today through Saturday
Gradual moisture advection from the south over the past 24 hours
has resulted in 50+ surface dewpoints spreading northward into
southern Illinois early this morning. Due to the increased low-level
moisture and nearly calm winds beneath ridge axis, areas of fog
are beginning to develop south of I-70. HRRR shows the fog
developing/spreading further north toward dawn. Have therefore
included patchy fog along and south of a Jacksonville to Paris
line through 14z/9am. Once early morning fog dissipates, partly to
mostly sunny skies and very warm conditions will prevail for the
remainder of the day. Afternoon high temperatures will be a degree
or two warmer than yesterday, with readings reaching the middle to
upper 70s.
As ridge only slowly shifts eastward, the potential exists for
more patchy fog tonight. Given increasing moisture, clear skies,
and continued light winds near the departing ridge axis, will
include fog mention for the eastern half of the KILX CWA. Further
west, light return flow should keep atmosphere mixed just enough
to prevent fog west of I-55. Once fog dissipates, another mostly
sunny and warm day will unfold on Friday...with highs reaching the
80-degree mark.
00z Oct 10 models have sped up the approach of the weekend system,
with FROPA now expected to occur Saturday afternoon. NAM is the
fastest of the models, but think it is too aggressive with pushing
the front eastward into the prevailing upper ridge. Will therefore
trend closer to the slightly slower ECMWF/GFS solution. With front
expected to be along the Mississippi River by 12z Saturday, will
maintain low chance POPs in the Illinois River Valley late Friday
night, then will spread rain chances further east across the
rest of the area on Saturday. With best upper support remaining
well to the N/NW and only a shallow moisture profile in place, am
not expecting a widespread soaking rainfall on Saturday. Will keep
POPs in the chance category accordingly. Since system is moving a
bit faster than previously forecast, will only hold on to chance
POPs across the eastern CWA into the evening hours, then will go
dry across the board overnight.
LONG TERM...Sunday through Wednesday
High pressure will build into the region behind the departing cold
front on Sunday, with models indicating a very dry airmass with
dewpoints in the lower to middle 40s settling in. Mostly clear and
dry weather is expected for both Sunday and Monday, with warm
afternoon highs in the upper 60s/lower 70s and cool overnight lows
in the 40s.
Next system is still slated to come into the picture early next
week, although details are not clear at this point. An upper-level
trough is expected to dig into the Rockies Sunday into Monday,
although how deep the system becomes and how quickly it lifts
northeastward are still very much in question. GFS is more
progressive with the system, with the upper low and its associated
surface wave ejecting into the western Great Lakes by Tuesday
evening. Meanwhile, latest ECMWF is deeper and holds the system
back in the Rockies/Plains until Thursday. Given significant
timing discrepancies, have opted to leave going forecast alone
until better agreement is achieved. As such, am expecting showers
and thunderstorms to develop across the area Monday night into
Tuesday, followed by cooler/drier weather by Wednesday.
Barnes
&&
.AVIATION...
ISSUED 629 AM CDT Thu Oct 10 2013
VFR conditions will continue next 24hrs at all TAF sites. Lower
level moisture streaming up into the area currently and will
continue through the day and into tonight. Sct to broken clouds
around 4kft being reported in the obs and satellite shows this as
well. Based on satellite loop and obs, will have broken cigs at
all sites except for PIA during the day. Then all sites will
scatter out for this evening with scattered clouds continuing
overnight tonight. Winds will be southerly to southeasterly
through the whole period. Winds speeds strongest during the day at
7-8kts but then decrease some after sunset.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
323 AM CDT THU OCT 10 2013
.DISCUSSION...
322 AM CDT
TODAY THROUGH TONIGHT...
SIMILAR STORY FOR TODAY...ABUNDANT SUNSHINE AND UNSEASONABLE
WARMTH ACROSS THE REGION. BROAD ANTI-CYCLONIC FLOW REMAINS
ANCHORED ACROSS THE EASTERN THIRD OF THE CONUS...WITH A WAVE
LIFTING NORTHEAST OFF OF THE VIRGINIA COAST. NEAR CLOUDLESS SKIES
WITH LIGHT TO CALM WINDS EARLY THIS MORNING ACROSS THE FORECAST
AREA. VWP FROM WSR-88D KLOT INDICATE WINDS REMAIN RATHER UNIFORM
FROM THE EAST AT 1-9KFT AGL. LOCATIONS ADJACENT TO LAKE MICHIGAN
IN FAR NORTHEAST IL CONTINUE TO SEE TEMPS HOLDING IN THE LOW
50S...WHILE FURTHER SOUTH IN THE METRO CHICAGO AREA TEMPS HOVER IN
THE MID 50S. ELSEWHERE TEMPS HAVE RADIATED INTO THE LOW/MID
40S...WITH T/TD SPREADS NEARING 2 DEG OR LESS. THE COMBINATION OF
MINIMAL T/TD SPREADS AND CALM WINDS HAS ALLOWED PATCHY FOG TO
DEVELOP AGAIN THIS MORNING. EXPECT A FEW LOW LYING AREAS TO SEE
VSBYS REDUCED TO ARND 1SM...HOWEVER SHOULD ONLY LINGER UNTIL JUST
AFTER DAYBREAK. SHORTLY AFT SUNRISE THE SFC SHUD QUICKLY WARM
GIVEN THE PAST SEVERAL DAYS OF DRY CONDS. THIS HAS RESULTED IN
REDUCED HEAT CAPACITY...AND ATMOSPHERIC PARCELS WILL RESPOND TO
THE SOLAR RADIATION IN THE FORM OF A LARGE DIURNAL SWING IN TEMPS
TODAY. PLUMES SUGGEST TEMPS WILL BE IN THE MID/UPR 70S FOR MUCH OF
THE CWFA...WITH THE EXCEPTION OF AREAS ADJACENT TO LAKE MICHIGAN.
AN AFTN LAKE BREEZE IS EXPECTED TO DEVELOP AND PUSH INLAND...WHICH
WILL LIKELY CAP TEMPS DOWNTOWN CHICAGO IN THE UPR 60S.
TONIGHT DRY WEATHER CONTINUES WITH NEAR CLOUDLESS SKIES YET
AGAIN...A FEW CIRRUS CLOUDS MAY SLIDE OVERHEAD WHICH MAY SLOW THE
RATE OF COOLING TONIGHT. THUS IT APPEARS TEMPS WILL LIKELY BE
SLIGHTLY WARMER IN THE LOW 50S...WITH A FEW TRADITIONAL LOCATIONS
RADIATING INTO THE UPR 40S.
CONFIDENCE...HIGH.
FRIDAY THROUGH SATURDAY...
MID-LVL RIDGING CONTINUES TO HANG TOUGH THROUGH MUCH OF FRI...AS
THE STRENGTH OF THE 500MB RIDGE OVER QUEBEC/EASTERN ONTARIO REMAINS
PROGGED AT 3 SIGMA. GIVEN THE STRENGTH OF THE DOWNSTREAM RIDGE
THROUGH FRI NGT...IT APPEARS TO BE HAVING A SIGNIFICANT DIMINISHING
ROLE IN THE APPROACHING MID-LVL SHORTWAVE THAT WILL LIFT NORTHEAST
FROM THE FOUR-CORNERS REGION. OPERATIONAL GUIDANCE HAS CONTINUED TO
TREND DRIER WITH THIS SYSTEM...WITH THE EARLIEST PRECIP NOT ARRIVING
UNTIL ARND DAYBREAK SAT. LCL WRF MODEL THRU 12Z SAT INDICATES DRY
WEATHER WITH THE FRONTAL BOUNDARY MUCH FASTER AND NEARING FAR
NORTHWEST IL ARND DAYBREAK SAT. EC/GFS BOTH HAVE TRENDED DRIER WITH
THE EARLY WEEKEND SYSTEM...WITH THE BEST DYNAMICS PASSING WELL
NORTHWEST OF THE FORECAST AREA SAT. IT IS CONCEIVABLE THAT SAT MAY
JUST SEE SPOTTY SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM SOUTH
OF I-80...AS MUCAPE IN THE SFC-500MB LAYER HOVERS ARND 200-400J/KG.
THIS TOO HAS BEEN ON A DECREASING TREND.
AT THIS TIME HAVE HELD ONTO MENTION OF ISOLATED THUNDER FOR SAT THRU
SAT EVE...THEN WITH THE FORWARD SPEED INCREASING FOR SAT NGT HAVE
PULLED MENTION OF PRECIP AFT MIDNIGHT. FLOW THEN TURNS NORTHWEST
BEHIND THE BOUNDARY...WITH COOLER/DRIER AIR FILTERING INTO THE CWFA
FOR THE REMAINDER OF THE WEEKEND.
TEMPS FRI AHEAD OF THE SYSTEM WILL LIKELY BE WARM AGAIN...WITH
STRONG SOUTHEASTERLY TURNING SOUTHERLY FLOW. MANY PLUMES INDICATE
TEMPS WILL BE IN THE MID/UPR 70S FRI...AND COULD PERHAPS SEE A
HANDFUL OF POINTS REACH 80 DEGREES SOUTH OF A LASALLE TO KANKAKEE
LINE. THEN WITH INCREASED CLOUD COVER FRI NGT TEMPS WILL REMAIN MILD
IN THE MID/UPR 50S. DEPENDING ON THE TIMING OF FRONTAL PASSAGE
SAT...AND IF CLOUD COVER CAN ERODE QUICK ENOUGH BEFORE
SUNSET...TEMPS COULD STILL WARM INTO THE LOW/MID 70S. THE WARMEST
LOCATIONS WILL LIKELY BE THE SOUTHEAST CWFA WHERE TEMPS MAY TOUCH 80
DEG SAT AFTN.
CONFIDENCE...HIGH.
SUNDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE CONTINUED TO PROG SLOW WEAKENING IN THE 500MB RIDGE
OVER QUEBEC SUN...WITH THE TROUGH OVER THE CENTRAL CONUS FLATTENING.
AN ELONGATED TROUGH APPEARS TO SETUP SUN NGT STRETCHING SOUTHWEST
THROUGH THE ROCKIES...THEN RIDGING IS POISED TO DEVELOP ACROSS THE
PAC-NW MON INTO TUE. THE INCREASING MID-LVL HEIGHTS ACROSS THE
PAC-NW/WESTERN CANADA WILL PLAY A ROLE IN A POSSIBLE PATTERN
ADJUSTMENT TOWARDS THE MIDDLE OF NEXT WEEK.
OPERATIONAL GUIDANCE SLIDES SFC RIDGE INTO THE REGION SUN THRU
MON...THEN QUICKLY DRIFTS NORTHEAST MON NIGHT. OPERATIONAL GUIDANCE
HAS COME INTO BETTER AGREEMENT WITH A SHORTWAVE LIFTING INTO THE
CENTRAL PLAINS MON NGT...WITH CONSIDERABLE MOISTURE BEING PUMPED
INTO THIS FEATURE. GUIDANCE THEN BRINGS PRECIP NORTHEAST INTO THE
FORECAST AREA MON NGT/TUE. SOME UNCERTAINTY REMAINS WITH RESPECT TO
THE TIMING/COVERAGE OF PRECIP...HOWEVER CONCEPTUALLY THIS SYSTEM
WOULD LIKELY PRODUCE A DECENT SLUG OF PRECIP TUE BEFORE A DRY SLOT
PIVOTS EAST TUE NGT/WED.
THE OVERALL THEME WITH TEMPS IN THE EXTENDED PERIODS IS MORE OF A
SEASONAL SETUP...HOWEVER TEMPS COULD REMAIN MUCH COOLER IF ABUNDANT
PRECIP DOES DEVELOP. THIS COULD HOLD TEMPS IN THE MID/UPR 50S...AT
THIS POINT HAVE HELD ONTO TEMPS IN THE LOW/MID 60S.
THEN TOWARDS THE MIDDLE OF NEXT WEEK WITH THE AFOREMENTIONED RIDGING
ACROSS THE PAC-NW/WESTERN CANADA REMAINING IN PLACE...THIS WILL
LIKELY PROVIDE COOLER AIR TO SLIDE SOUTHEAST ACROSS CENTRAL CANADA
AND PUSH IN BEHIND THE EARLY WEEK SYSTEM INTO THE CWFA WED. HIGHS
WED MAY STRUGGLE TO WARM BEYOND THE MID 50S.
CONFIDENCE...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LIGHT/SHALLOW FOG THIS MORNING.
* LAKE BREEZE THIS AFTERNOON. CMS
//DISCUSSION...UPDATED 06Z...
A RIDGE OF HIGH PRESSURE EXTENDS OVER THE GREAT LAKES REGION THIS
MORNING AND WILL VERY SLOWLY DRIFT EAST TONIGHT AND FRIDAY. WINDS
WILL REMAIN LIGHT AND VARIABLE OR CALM THROUGH SUNRISE THEN TURN
SOUTHEASTERLY...WITH SPEEDS UNDER 10KTS. THIS HIGH WILL ALSO A
LAKE BREEZE TO FORM WITH WINDS TURNING EASTERLY AT ORD/MDW BY MID
AFTERNOON...NORTHEASTERLY AT GYY. WINDS WILL THEN SETTLE BACK TO
LIGHT SOUTHEASTERLY AFTER SUNSET.
PATCHES OF LIGHT/SHALLOW GROUND FOG HAVE DEVELOPED IN SOME AREAS
INCLUDING AT GYY. AS TEMPS COOL TOWARD THE DEWPOINTS...EXPECT FOG
TO CONTINUE TO DEVELOP IN COVERAGE AND CURRENT MVFR VIS WITH
SHALLOW FOG MENTION AT RFD/DPA/GYY SEEMS REASONABLE...THOUGH SOME
AREAS...PERHAPS NORTH OF THE TERMINALS INTO SOUTHERN WI...COULD
BECOME MORE WIDESPREAD IFR VIS OR LOWER. POSSIBLE TO SEEM SOME
4-6SM VIS AT ORD/MDW BEFORE SUNRISE BUT CONFIDENCE IS LOW AND
HAVE LEFT OUT OF THIS FORECAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW FOR LIGHT/SHALLOW FOG THIS MORNING.
* HIGH FOR A LAKE BREEZE REACHING ORD/MDW...MEDIUM FOR TIMING. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
* FRIDAY...DRY/VFR.
* SATURDAY...CHANCE OF SHRA/TSRA.
* SUNDAY AND MONDAY...DRY/VFR.
* TUESDAY...SLIGHT CHANCE OF SHRA.
KJB
&&
.MARINE...
300 AM...A LARGE RIDGE OF HIGH PRESSURE EXTENDING FROM THE WESTERN
LAKES TO NEW ENGLAND WILL SLOWLY DRIFT SOUTHEAST TONIGHT AND FRIDAY
AND EVENTUALLY MERGE WITH STRONGER HIGH PRESSURE MOVING SOUTHEAST
ACROSS QUEBEC FRIDAY AND FRIDAY NIGHT. THIS WILL MAINTAIN MAINLY
SOUTHEASTERLY FLOW OVER THE LAKE INTO FRIDAY WITH SPEEDS GRADUALLY
INCREASING INTO THE 10-20 KT RANGE FRIDAY. WEAK LOW PRESSURE NEAR
COLORADO THIS MORNING WILL DEEPEN AS IT MOVES NORTH ACROSS THE
DAKOTAS FRIDAY AND ACROSS MANITOBA AND WESTERN ONTARIO FRIDAY
NIGHT. THIS WILL CAUSE THE GRADIENT TO TIGHTEN ACROSS THE WESTERN
LAKES FRIDAY NIGHT INTO SATURDAY MORNING WITH A PERIOD OF 20-25KTS
POSSIBLE. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE SATURDAY
AFTERNOON OR SATURDAY EVENING SHIFTING WINDS TO THE WEST AND THEN
TO THE NORTHWEST SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE LAKES REGION SUNDAY INTO SUNDAY
NIGHT. ANOTHER LOW PRESSURE IS EXPECTED TO MOVE FROM THE CENTRAL
PLAINS MONDAY ACROSS THE LAKES REGION TUESDAY INTO WEDNESDAY...
THOUGH CONFIDENCE REGARDING THE STRENGTH AND TRACK OF THIS SYSTEM
REMAINS LOW AT THIS TIME. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
305 AM CDT Thu Oct 10 2013
.DISCUSSION...
ISSUED 305 AM CDT Thu Oct 10 2013
SHORT TERM...Today through Saturday
Gradual moisture advection from the south over the past 24 hours
has resulted in 50+ surface dewpoints spreading northward into
southern Illinois early this morning. Due to the increased low-level
moisture and nearly calm winds beneath ridge axis, areas of fog
are beginning to develop south of I-70. HRRR shows the fog
developing/spreading further north toward dawn. Have therefore
included patchy fog along and south of a Jacksonville to Paris
line through 14z/9am. Once early morning fog dissipates, partly to
mostly sunny skies and very warm conditions will prevail for the
remainder of the day. Afternoon high temperatures will be a degree
or two warmer than yesterday, with readings reaching the middle to
upper 70s.
As ridge only slowly shifts eastward, the potential exists for
more patchy fog tonight. Given increasing moisture, clear skies,
and continued light winds near the departing ridge axis, will
include fog mention for the eastern half of the KILX CWA. Further
west, light return flow should keep atmosphere mixed just enough
to prevent fog west of I-55. Once fog dissipates, another mostly
sunny and warm day will unfold on Friday...with highs reaching the
80-degree mark.
00z Oct 10 models have sped up the approach of the weekend system,
with FROPA now expected to occur Saturday afternoon. NAM is the
fastest of the models, but think it is too aggressive with pushing
the front eastward into the prevailing upper ridge. Will therefore
trend closer to the slightly slower ECMWF/GFS solution. With front
expected to be along the Mississippi River by 12z Saturday, will
maintain low chance POPs in the Illinois River Valley late Friday
night, then will spread rain chances further east across the
rest of the area on Saturday. With best upper support remaining
well to the N/NW and only a shallow moisture profile in place, am
not expecting a widespread soaking rainfall on Saturday. Will keep
POPs in the chance category accordingly. Since system is moving a
bit faster than previously forecast, will only hold on to chance
POPs across the eastern CWA into the evening hours, then will go
dry across the board overnight.
LONG TERM...Sunday through Wednesday
High pressure will build into the region behind the departing cold
front on Sunday, with models indicating a very dry airmass with
dewpoints in the lower to middle 40s settling in. Mostly clear and
dry weather is expected for both Sunday and Monday, with warm
afternoon highs in the upper 60s/lower 70s and cool overnight lows
in the 40s.
Next system is still slated to come into the picture early next
week, although details are not clear at this point. An upper-level
trough is expected to dig into the Rockies Sunday into Monday,
although how deep the system becomes and how quickly it lifts
northeastward are still very much in question. GFS is more
progressive with the system, with the upper low and its associated
surface wave ejecting into the western Great Lakes by Tuesday
evening. Meanwhile, latest ECMWF is deeper and holds the system
back in the Rockies/Plains until Thursday. Given significant
timing discrepancies, have opted to leave going forecast alone
until better agreement is achieved. As such, am expecting showers
and thunderstorms to develop across the area Monday night into
Tuesday, followed by cooler/drier weather by Wednesday.
Barnes
&&
.AVIATION...
ISSUED 1125 PM CDT Wed Oct 9 2013
Main forecast concern will be with the development of fog in the 08z
to 13z time frame, with VFR conditions expected for the remainder of
the forecast period. Persistent S-SE flow has gradually drawn moisture
northward into parts of south central IL late this evening with sfc
dew points in the 50s along the I-70 corridor. Temp-dew point spreads
already down to between 3-5 degrees in parts of our area so with a
light wind and clear sky, it appears that a few locations in our
taf area will see MVFR vsbys late tonight. What fog we do see should
dissipate by 15z with the next concern being with sct-bkn cu forming
by 18z. Forecast soundings suggest cig bases around 4000 feet during
the afternoon with the better probabilities for bkn cigs at SPI and
DEC. Light and variable winds today will turn more into a southerly
direction around 10 kts on Thursday, and then back into a light
southeast flow Thursday night with speeds around 5 kts.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
146 PM MDT THU OCT 10 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 145 PM MDT THU OCT 10 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW STRONG TROUGH
WITH CLOSED CENTER JUST WEST OF FOUR CORNERS REGION...AND
SOUTH-SOUTHWEST FLOW OVER EASTERN COLORADO/WESTERN KANSAS. 120-125KT
H3 JET STREAK IS ROUNDING THE BASE OF THE TROUGH WITH NOSE OF JET
STREAK BEGINNING TO MOVE INTO SOUTHERN COLORADO. AT THE SURFACE A
STATIONARY FRONT HAS LINGERED OVER NW KS THROUGH MOST OF THE
DAY...WITH LATEST OBS TRENDS INDICATING THE FRONT HAS FINALLY PUSHED
NORTH OF KGLD TOWARDS THE NORTHWEST PART OF OUR CWA.
UPPER LEVEL TROUGH IS EXPECTED TO MOVE NORTHEAST BECOMING NEGATIVELY
TILTED OVER NORTHEAST COLORADO/SOUTHWEST NEBRASKA BY 06Z WITH BEST
FORCING AHEAD OF THIS FEATURE. MODELS ARE STILL IN AGREEMENT THAT
BEST FORCING OVER OUR CWA WILL BE THIS EVENING WITH STRONG
SUBSIDENCE AND DRY SLOT MOVING OVER THE CWA BETWEEN 06Z-03Z.
FORECAST INITIATION MAY BE SLOWER THAN ORIGINALLY THOUGHT THIS
AFTERNOON DUE TO HIGH CINH AND WEAK LOW LEVEL MOISTURE RETURN
LIMITING CAPE EARLY THIS AFTERNOON. THERE HAS BEEN SOME VIRGA
APPARENT ON RADAR...HOWEVER MAIN ACTIVITY LIKELY WONT GET GOING
UNTIL CLOSER TO 00Z. MODELS MAY BE TOO HIGH ON TD WITH LOW LEVEL
AIR MASS LIKELY ORIGINATING OVER THE TX/OK PANHANDLES WHERE TD VALUES
RANGE FROM THE 40S TO LOW 50S. THIS WILL IMPACT HOW MUCH CAPE WILL
BE AVAILABLE OVER THE CWA. AT THIS POINT RAP SOLUTION OF 500-600
J/KG ML CAPE SEEMS TO BE THE MOST REASONABLE...THOUGH I WOULDNT RULE
OUT EASTERN LOCATIONS GETTING HIGHER ELEVATED INSTABILITY AFTER 00Z.
WITH LOW LEVEL LAPSE RATES CONTINUING TO STEEPEN THIS AFTERNOON WE
SHOULD SEE SHOWER/THUNDERSTORM DEVELOPMENT ALONG KS/CO BORDER WHERE
CONVERGENCE ALONG FRONT/SURFACE TROUGH WILL PROVIDE FORCING. BETTER
COVERAGE WILL BE ASSOCIATED WITH INCREASING LARGE SCALE SUPPORT FROM
UPPER TROUGH WHICH SHOULD MOVE INTO THE CWA AROUND 00Z FROM THE
WEST. MODELS CONTINUE TO INDICATE SHOWERS/THUNDERSTORMS FORMING INTO
A LINE OR MULTI-CELL CLUSTER BY THIS EVENING AND QUICKLY MOVING
EAST...WHICH IS REASONABLE CONSIDERING THE UNIDIRECTIONAL SHEER
PROFILES IN PLACE. I STILL EXPECT WIND TO BE THE PRIMARY THREAT WITH
THUNDERSTORMS...THOUGH IF WE CAN GET AN ORGANIZED/DISCREET CELL THEN
SEVERE HAIL WILL CERTAINLY BE POSSIBLE.
REGARDING WINDS...WIND SPEEDS HAVE BEEN CLOSE TO ADVISORY CRITERIA
IN THE WEST AND WITH LEE TROUGH STILL DEEPENING I EXPECT MOST
LOCATIONS IN OUR CWA TO REACH CRITERIA BY LATE THIS AFTERNOON.
GFS/MAV GUIDANCE STILL SUPPORTS NEAR WARNING CONDITIONS...WHICH IS
PROBABLY TOO WINDY CONSIDERING EXPECTED MIXING HEIGHTS. UNLESS WE SEE
A SHOWER/THUNDERSTORM MIX WINDS FROM ABOUT 700-750MB I THINK WE
SHOULD REMAIN BELOW WARNING CRITERIA. THIS WILL NEED TO BE
MONITORED. WINDS SHOULD DIMINISH AROUND 03Z THOUGH THEY WILL REMAIN
BREEZY THROUGH FRIDAY. NW WINDS WILL INCREASE BEHIND UPPER LOW
FRIDAY AFTERNOON...AND COULD APPROACH ADVISORY CRITERIA ACROSS THE
NORTH. BASED ON CURRENT GUIDANCE IT APPEARS THE STRONGEST WINDS WILL
REMAIN NORTH OF OUR CWA...SO NO ADVISORY IS PLANNED FOR FRI
AFTERNOON AT THIS TIME.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 1239 PM MDT THU OCT 10 2013
A SECONDARY VORT LOBE ROTATING THROUGH NORTHERN COLORADO FRIDAY
NIGHT MIGHT BE ENOUGH TO PRODUCE A FEW ISOLATED LIGHT RAIN
SHOWERS...BUT FORCING WILL BE WEAK AND MOISTURE LACKING. LOW LEVEL
RETURN FLOW GETS UNDERWAY ON SATURDAY WITH INCREASING
SOUTHEASTERLY WINDS. TEMPERATURES SHOULD REBOUND QUICKLY AND
RAISED HIGHS AS MUCH AS ISC ALLOWED. AS THE NEXT SYSTEM ORGANIZES
IN THE GREAT BASIN...A SERIES OF SHORTWAVE TROUGHS WILL EJECT OUT
AHEAD OF IT ACROSS THE CENTRAL ROCKIES AND ADJACENT PLAINS. THERE
WILL BE LOW CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS
BEGINNING AND SUNDAY BUT INCREASING SUNDAY NIGHT AND MONDAY AS THE
MAIN ENERGY APPROACHES. BREEZY TO WINDY CONDITIONS WILL DEVELOP
BOTH SUNDAY AND MONDAY WHICH MAY REQUIRE HIGHLIGHTS. MODELS IN
VERY POOR AGREEMENT ON EVOLUTION OF THAT SYSTEM PAST MONDAY...THE
ECMWF MUCH SLOWER TO KICK IT OUT COMPARED TO THE PROGRESSIVE GFS
SOLUTION. AS A RESULT...THERE WILL BE SOME LINGERING LOW POPS
THROUGH THE REMAINDER OF THE PERIOD. TEMPERATURES WILL BE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH MONDAY...FOLLOWED BY BELOW NORMAL
TUESDAY THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1122 AM MDT THU OCT 10 2013
VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK TERMINALS...THOUGH MVFR CONDITIONS COULDNT BE RULED OUT IF
A HEAVIER SHOWER/THUNDERSTORM DEVELOPS AT EITHER SITE. GUSTY WINDS
WILL CONTINUE TO INCREASE THIS AFTERNOON AND CONTINUE THROUGH THE
TAF PERIOD...WITH STRONGEST WINDS LATE THIS AFTERNOON THROUGH THE
EARLY PART OF THE EVENING. WINDS WILL START FROM A SOUTHEASTERLY
DIRECTION SHIFTING TO THE SOUTH-SOUTHWEST...AND THEN BACKING TO
THE NW BY FRIDAY MORNING BEHIND MAIN SYSTEM. SHOWERS/THUNDERSTORMS
WILL DEVELOP THIS AFTERNOON AND OVERSPREAD BOTH TERMINALS THIS
EVENING UPPER LEVEL SYSTEM SHIFTS EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
KSZ001>004-013>016-027>029-041-042.
CO...WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR COZ090>092.
NE...WIND ADVISORY UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
252 AM MDT THU OCT 10 2013
.UPDATE...
ISSUED AT 806 PM MDT WED OCT 9 2013
UPDATED FORECAST TO INCLUDE A WIND ADVISORY ACROSS ROUGHLY THE
SOUTHEAST 2/3 OF THE FORECAST AREA FROM MID DAY THROUGH THE
EVENING HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 149 PM MDT WED OCT 9 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS WESTERN CONUS WITH CLOSED 548DM H5 CENTER OVER
WESTCENTRAL CALIFORNIA. 135KT H3 JET IS ROUNDING WESTERN EXTENT OF
THIS TROUGH WITH WELL DEFINED PV HEIGHT ANOMALY OVER SOUTHERN
CALIFORNIA. SW FLOW AHEAD OF THIS FEATURE IS IN PLACE ACROSS THE
PLAINS. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING
FORM THE NORTHERN PLAINS ACROSS CENTRAL NEBRASKA TO NEAR KGLD AND
WEST TOWARDS NORTHCENTRAL COLORADO.
TONIGHT...WITH DRY/STABLE AIR MASS IN PLACE WE SHOULD SEE DRY
CONDITIONS CONTINUE THROUGH TONIGHT. FRONT IS PROGGED TO LIFT
NORTH THROUGH THE NIGHT WITH SLIGHTLY WARMER AIR MASS BUILDING
BACK OVER THE CWA. WHILE H85 TEMPS ARENT TOO DIFFERENT THAN LAST
NIGHT...WINDS MAY REMAIN IN THE 10-12KT RANGE WHICH COULD LIMIT
RADIATIONAL COOLING. I WENT AHEAD AND BUMPED OVERNIGHT LOWS UP A
LITTLE...THOUGH WITH CLEAR SKIES IF WINDS DIMINISH WE COULD END UP
WITH LOWS SIMILAR TO LAST NIGHT.
THURSDAY...LEE TROUGH DEEPENS THROUGH THE DAY THURSDAY WITH TIGHT
PRESSURE GRADIENT DEVELOPING BY THURSDAY AFTERNOON. CONFIDENCE IS
HIGH IN WINDY CONDITIONS...HOWEVER THERE ARE SOME MODEL
DISCREPANCIES REGARDING WINDS ALOFT...AND THUS PEAK GUST POTENTIAL.
BASED ON BL/ML WINDS ON THE NAM I WOULD BE CONFIDENT IN A PERIOD
OF ADVISORY LEVEL WINDS (GUSTS 45-50MPH). GFS CONTINUES TO BE THE
STRONGER MODEL...WITH HIGH END ADVISORY/NEAR WARNING CRITERIA. THE
STRONGEST WINDS APPEAR TO OCCUR AROUND 00Z WHEN MIXING MIGHT NOT
BE AS DEEP (CONSIDERING THE EARLIER SUNSET THIS TIME OF YEAR)...SO
I WAS NOT CONFIDENT ENOUGH TO ADD A HIGHLIGHT AT THIS
TIME.
PRECIPITATION CHANCES INCREASE FROM MID AFTERNOON THROUGH 00Z AS
LAPSE RATES STEEPEN ALONG SURFACE TROUGH IN EASTERN COLORADO.
TD VALUES GENERALLY IN THE 40S WILL LIMIT CAPE TO 500 J/KG OR
LESS...AND THUNDERSTORMS WILL BE HIGH BASED (LCL/LFC AROUND 10KFT).
AT THE SAME TIME UNIDIRECTIONAL SHEER WILL BE IMPRESSIVE AHEAD OF
TROUGH BY LATE AFTERNOON...AND SOUNDINGS ARE INDICATIVE OF STRONG
DOWNDRAFT POTENTIAL.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 252 AM MDT THU OCT 10 2013
A TROUGH SITUATED OVER THE PACIFIC NORTHWEST AT THE START OF THE
EXTENDED PERIOD WILL MOVE QUICKLY SOUTHEASTWARD TOWARD THE CENTRAL
ROCKIES BY LATE SUNDAY. WEAK UPPER RIDGING WILL SHIFT EAST DURING
THE DAY SUNDAY AND SIGNIFICANT STRENGTHENING OF MID/UPPER FLOW
OCCURS. IN RESPONSE TO THE APPROACHING SYSTEM...STRONG SOUTHEASTERLY
LOW LEVEL FLOW BECOMES REESTABLISHED ACROSS THE HIGH PLAINS. THE
PREVIOUS FRONTAL INTRUSION WILL HAVE ONLY MADE IT INTO THE SOUTHERN
PLAINS AND POOLING OF LOW LEVEL MOISTURE OVER ARKLATEX REGION WILL
QUICKLY BE ADVECTED NORTHWESTWARD INTO THE AREA BY SUNDAY NIGHT INTO
MONDAY. MODELS BEGIN TO DIFFER ON TIMING AND CHARACTER OF THE TROUGH
BY THIS TIME. OPERATIONAL GFS REMAINS THE FASTEST WITH PROGRESSING
THIS SYSTEM EASTWARD...EVEN CONSIDERABLY FASTER THAN GFS ENSEMBLE
MEAN. ECMWF AND GEM ARE SIMILAR IN PLACEMENT/TIMING AND BOTH ARE
MORE CLOSED OFF. THE SLOWER SOLUTION OF THE ECMWF AND GEM IS
PROBABLY MORE REALISTIC AND THE FORECAST IS WEIGHTED TOWARD A BLEND
OF THE TWO WITH REGARD TO TIMING. GREATEST PRECIPITATION CHANCES ARE
DEPICTED AFTER LOW LEVEL MOISTURE / HIGH PWATS ABOVE CLIMO ARRIVE
AND BEFORE FRONTAL PASSAGE WHICH WOULD OCCUR MONDAY EVENING.
A CURSORY GLANCE AT GFS FORECAST SOUNDINGS INDICATES AT LEAST SOME
ELEVATED INSTABILITY PRESENT BUT THE BOUNDARY LAYER IS SHOWN TO BE
RATHER COOL/STABLE...PERHAPS A BIT TOO MUCH GIVEN THE SYNOPTIC
PATTERN. WITH A SLIGHTLY FURTHER NORTHWEST TRACK OF SURFACE
LOW...CONSIDERABLE UPWARD ADJUSTMENT OF TEMPERATURES LATE SUNDAY
THROUGH MONDAY WOULD BE NEEDED ACROSS AT LEAST THE EASTERN PORTION
OF THE AREA AND A MORE FAVORABLE THERMODYNAMIC PROFILE MAY BE
PRESENT FOR A MORE ROBUST CONVECTIVE EPISODE. FOR NOW...HAVE
CONFINED GREATEST THUNDER CHANCES TO THE SOUTHEASTERN PORTION OF THE
AREA. ADDITIONALLY...WITH PWAT VALUES APPROACHING THE 99TH
PERCENTILE FOR OCTOBER AND THE 75TH PERCENTILE BY MID SUMMER
STANDARDS...HEAVY RAINFALL IS A POSSIBILITY.
MODEL SOLUTION DIFFERENCES CONTINUE TO GROW INTO EARLY/MID WEEK. IN
THE ECMWF THE TROUGH BECOMES ELONGATED ACROSS THE WESTERN CONUS
KEEPING OUR REGION IN SOUTHWESTERLY FLOW ALOFT THROUGH WEDNESDAY. A
CLOSED LOW BEGINS TO EVOLVE OVER NORTHERN UTAH AND WESTERN WYOMING
BY LATE TUESDAY AND WEDNESDAY AND HEIGHT VALUES THAT WOULD SUPPORT
NEAR OR ABOVE NORMAL TEMPERATURES. ON THE CONTRARY...GFS HAS THE
UPPER LEVEL TROUGH AXIS POSITIONED WELL EAST OF THE AREA AND COOL
NORTHWESTERLY SURFACE FLOW WITH BELOW NORMAL TEMPERATURES AS
INDICATED BY MEX MOS. GFS ENSEMBLE IS A COMPROMISE BUT IS CLOSER TO
THE MORE PROGRESSIVE OPERATIONAL GFS. CONFIDENCE IN THE LATTER HALF
OF THE EXTENDED PERIOD IS SO LOW THAT A FORECAST OF CLIMATOLOGICALLY
NORMAL CONDITIONS WOULD PROBABLY THE BEST APPROACH.
HOWEVER...ALLBLEND SEEMS TO BE SIGNIFICANTLY WEIGHTED TOWARD THE
GFS/GEFS AND DID NOT DEVIATED FROM THAT AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1149 PM MDT WED OCT 9 2013
VFR CONDITIONS SHOULD PREVAIL AT BOTH MCK AND GLD THROUGH THE TAF
PERIOD. A FEW HIGH CLOUDS WILL BE OBSERVED ALONG WITH LIGHT WINDS
OVERNIGHT THAT WILL BECOME STRONG AND GUSTY OUT OF THE SOUTH
BETWEEN 18Z-03Z AS THE SURFACE TROUGH OVER EASTERN COLORADO AND
WESTERN KANSAS DEEPENS AHEAD OF THE MAIN UPPER TROUGH MOVING
THROUGH THE SOUTHWEST U.S. AND INTO THE CENTRAL ROCKIES BY 06Z
THURSDAY NIGHT. AHEAD OF THE SURFACE TROUGH AND MAIN UPPER
TROUGH...THUNDERSTORMS WILL LIKELY FORM AND SPREAD EASTWARD
THROUGH THE EVENING. STRONG GUSTY WINDS ARE POSSIBLE FROM THESE
STORMS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM NOON MDT /1 PM CDT/ TODAY TO 9 PM MDT /10 PM
CDT/ THIS EVENING FOR KSZ002>004-013>016-027>029-041-042.
CO...WIND ADVISORY FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
COZ092.
NE...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS EVENING
FOR NEZ081.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...BRB
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1202 AM MDT THU OCT 10 2013
.UPDATE...
ISSUED AT 806 PM MDT WED OCT 9 2013
UPDATED FORECAST TO INCLUDE A WIND ADVISORY ACROSS ROUGHLY THE
SOUTHEAST 2/3 OF THE FORECAST AREA FROM MID DAY THROUGH THE
EVENING HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 149 PM MDT WED OCT 9 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS WESTERN CONUS WITH CLOSED 548DM H5 CENTER OVER
WESTCENTRAL CALIFORNIA. 135KT H3 JET IS ROUNDING WESTERN EXTENT OF
THIS TROUGH WITH WELL DEFINED PV HEIGHT ANOMALY OVER SOUTHERN
CALIFORNIA. SW FLOW AHEAD OF THIS FEATURE IS IN PLACE ACROSS THE
PLAINS. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING
FORM THE NORTHERN PLAINS ACROSS CENTRAL NEBRASKA TO NEAR KGLD AND
WEST TOWARDS NORTHCENTRAL COLORADO.
TONIGHT...WITH DRY/STABLE AIR MASS IN PLACE WE SHOULD SEE DRY
CONDITIONS CONTINUE THROUGH TONIGHT. FRONT IS PROGGED TO LIFT
NORTH THROUGH THE NIGHT WITH SLIGHTLY WARMER AIR MASS BUILDING
BACK OVER THE CWA. WHILE H85 TEMPS ARENT TOO DIFFERENT THAN LAST
NIGHT...WINDS MAY REMAIN IN THE 10-12KT RANGE WHICH COULD LIMIT
RADIATIONAL COOLING. I WENT AHEAD AND BUMPED OVERNIGHT LOWS UP A
LITTLE...THOUGH WITH CLEAR SKIES IF WINDS DIMINISH WE COULD END UP
WITH LOWS SIMILAR TO LAST NIGHT.
THURSDAY...LEE TROUGH DEEPENS THROUGH THE DAY THURSDAY WITH TIGHT
PRESSURE GRADIENT DEVELOPING BY THURSDAY AFTERNOON. CONFIDENCE IS
HIGH IN WINDY CONDITIONS...HOWEVER THERE ARE SOME MODEL
DISCREPANCIES REGARDING WINDS ALOFT...AND THUS PEAK GUST POTENTIAL.
BASED ON BL/ML WINDS ON THE NAM I WOULD BE CONFIDENT IN A PERIOD
OF ADVISORY LEVEL WINDS (GUSTS 45-50MPH). GFS CONTINUES TO BE THE
STRONGER MODEL...WITH HIGH END ADVISORY/NEAR WARNING CRITERIA. THE
STRONGEST WINDS APPEAR TO OCCUR AROUND 00Z WHEN MIXING MIGHT NOT
BE AS DEEP (CONSIDERING THE EARLIER SUNSET THIS TIME OF YEAR)...SO
I WAS NOT CONFIDENT ENOUGH TO ADD A HIGHLIGHT AT THIS
TIME.
PRECIPITATION CHANCES INCREASE FROM MID AFTERNOON THROUGH 00Z AS
LAPSE RATES STEEPEN ALONG SURFACE TROUGH IN EASTERN COLORADO.
TD VALUES GENERALLY IN THE 40S WILL LIMIT CAPE TO 500 J/KG OR
LESS...AND THUNDERSTORMS WILL BE HIGH BASED (LCL/LFC AROUND 10KFT).
AT THE SAME TIME UNIDIRECTIONAL SHEER WILL BE IMPRESSIVE AHEAD OF
TROUGH BY LATE AFTERNOON...AND SOUNDINGS ARE INDICATIVE OF STRONG
DOWNDRAFT POTENTIAL.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 1246 PM MDT WED OCT 9 2013
STRONG SHORTWAVE TROUGH WILL BRING WIDESPREAD SHOWERS AND
THUNDERSTORMS THURSDAY EVENING TO THE AREA. LACK OF MOISTURE/WEAK
INSTABILITY CONTINUE TO BE THE LIMITING FACTORS FOR MORE INTENSE
CONVECTION. NONETHELESS...HIGH BASED THUNDERSTORMS WILL DEVELOP
ALONG THE LEE TROUGH IN EASTERN COLORADO AND MOVE EAST AS A SQUALL
LINE IN THE EVENING...WHILE INDIVIDUAL CELLS RACE NORTHEAST AT
AROUND 50KTS. DESPITE FAVORABLE SHEAR PROFILES...UPDRAFTS WILL
STRUGGLE TO ORGANIZE GIVEN SBCAPE OF LESS THAN 500 J/KG. AS A
RESULT...HAIL THREAT SEEMS MINIMAL AND TORNADO THREAT EVEN
LESS...HOWEVER DAMAGING WINDS WILL BE LIKELY WITH STRONGEST
STORMS GIVEN HIGH BASES AND UNIDIRECTIONAL WINDS THROUGH NEARLY
THE ENTIRE TROPOSPHERE. PRECIPITATION WILL END BY 06Z AS SYSTEM
QUICKLY LIFTS INTO THE NORTHERN PLAINS.
FRIDAY WILL BE COOLER AND DRY...BUT ANOTHER VORT LOBE WILL ROTATE
THROUGH THE BASE OF THE LONGWAVE TROUGH FRIDAY NIGHT.
HOWEVER...THERE WILL NOT BE ENOUGH TIME FOR MOISTURE RETURN AND
THE WEAK LIFT WILL HAVE DIFFICULTY IN GENERATING MORE THAN A FEW
ISOLATED TO WIDELY SCATTERED RAIN SHOWERS ACROSS NORTHERN PORTIONS
OF THE AREA FRIDAY NIGHT THROUGH SATURDAY MORNING. SHORTWAVE
RIDGING WILL BRIEFLY FOLLOW SATURDAY AFTERNOON AND SATURDAY
NIGHT...HOWEVER ANOTHER WEAK TROUGH WILL BE MOVING THROUGH THE
FLOW ON SUNDAY BRINGING LOW CHANCES OF SHOWERS AND PERHAPS AN
ISOLATED THUNDERSTORM AS SOME WEAK INSTABILITY IS FORECAST. THE
MAIN SYSTEM WILL EJECT ACROSS THE CENTRAL AND NORTHERN ROCKIES
MONDAY WITH PRECIPITATION CHANCES CONTINUING AS ASSOCIATED SURFACE
COLD FRONT MOVES THROUGH DURING THE DAY ON MONDAY. BREEZY
NORTHWEST WINDS WILL FOLLOW FRONTAL PASSAGE MONDAY AFTERNOON AND
EVENING AS PRECIPITATION COMES TO AN END.
THE REMAINDER OF THE PERIOD (TUESDAY AND WEDNESDAY) WILL SEE DRY
NORTHWEST FLOW WITH TEMPERATURES SLIGHTLY BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1149 PM MDT WED OCT 9 2013
VFR CONDITIONS SHOULD PREVAIL AT BOTH MCK AND GLD THROUGH THE TAF
PERIOD. A FEW HIGH CLOUDS WILL BE OBSERVED ALONG WITH LIGHT WINDS
OVERNIGHT THAT WILL BECOME STRONG AND GUSTY OUT OF THE SOUTH
BETWEEN 18Z-03Z AS THE SURFACE TROUGH OVER EASTERN COLORADO AND
WESTERN KANSAS DEEPENS AHEAD OF THE MAIN UPPER TROUGH MOVING
THROUGH THE SOUTHWEST U.S. AND INTO THE CENTRAL ROCKIES BY 06Z
THURSDAY NIGHT. AHEAD OF THE SURFACE TROUGH AND MAIN UPPER
TROUGH...THUNDERSTORMS WILL LIKELY FORM AND SPREAD EASTWARD
THROUGH THE EVENING. STRONG GUSTY WINDS ARE POSSIBLE FROM THESE
STORMS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM NOON MDT /1 PM CDT/ TO 9 PM MDT /10 PM CDT/
THURSDAY FOR KSZ002>004-013>016-027>029-041-042.
CO...WIND ADVISORY FROM NOON TO 9 PM MDT THURSDAY FOR COZ092.
NE...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS EVENING
FOR NEZ081.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...024
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GRAY ME
513 PM EDT THU OCT 10 2013
.SYNOPSIS...
HIGH PRESSURE WILL HOLD OVER THE REGION TONIGHT AND FRIDAY. A WEAK
BACK DOOR COLD FRONT WILL SLOWLY SAG SOUTHWEST THROUGH THE REGION
FRIDAY NIGHT THROUGH SATURDAY. HIGH PRESSURE WILL BUILD IN FROM
THE NORTHEAST BEHIND THE FRONT SATURDAY NIGHT AND SUNDAY. HIGH
PRESSURE WILL GRADUALLY SHIFT OFF TO THE EAST SUNDAY NIGHT AS A
COLD FRONT APPROACHES FROM THE NORTHWEST. THE FRONT WILL STALL
ACROSS NORTHERN NEW ENGLAND ON MONDAY AND THEN LIFT NORTH AS A
WARM FRONT ON TUESDAY. A COLD FRONT WILL APPROACH FROM THE WEST ON
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
QUIET WEATHER WILL CONTINUE ACROSS THE NORTHEAST AS HIGH PRESSURE
REMAINS IN CONTROL. ONLY FLY IN THE OINTMENT IS THE CUTOFF SYSTEM
OVER THE MID ATLANTIC STATES WHICH IS CURRENTLY THROWING A FAIR
AMOUNT OF HIGH CLOUDINESS ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA. HIGH LEVEL MOISTURE WILL CONTINUE TO SPREAD NORTH THROUGH
THE REMAINDER OF THE AFTERNOON AND OVERNIGHT BEFORE GRADUALLY
RETREATING ON FRIDAY. INCREASING MID LEVEL MOISTURE ACROSS FAR
SOUTHERN NEW HAMPSHIRE WILL LIKELY HELP TO KEEP TEMPS UP IN THIS
AREA OVERNIGHT. MODELS STILL TRYING TO INTRODUCE SOME LOW CHANCE
POPS INTO SOUTHERN NEW HAMPSHIRE OVERNIGHT AND EARLY FRIDAY BUT
HAVE SCALED THESE BACK CONSIDERING THE VERY DRY AIRMASS IN PLACE
OVER THE REGION. WILL SEE A SLIGHTLY WARMER NIGHT WITH LOWS
RANGING THROUGH THE 30S IN THE NORTH AND MID 30S TO MID 40S IN THE
SOUTH.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. DEW POINTS REMAIN
RELATIVELY HIGH...SO WILL BE MONITORING FOR POSSIBLE PATCHY FOG IF
SKIES CLEAR OVER CENTRAL AND NORTHERN AREAS.
LATEST HRRR MODEL CONTINUES TO SHOW ANY PRECIPITATION REMAINING
WELL TO OUR SOUTHWEST DURING THE OVERNIGHT HOURS...WITH VERY DRY
AIR IN PLACE ACROSS NORTHERN NEW ENGLAND. OTHERWISE...NO
SIGNIFICANT CHANGES TO THE FORECAST.
PREV DISC...
EXPECT FRIDAY TO START OUT WITH MOSTLY CLOUDY SKIES BUT THIS
MOISTURE WILL GRADUALLY DIMINISH AS THE DAY GOES ON. SHOULD SEE
HIGHS PUSHING ABOVE NORMAL WITH CENTRAL AND NORTHERN AREAS TOPPING
OUT IN THE LOWER 70S. EASTERLY FLOW WILL HOLD TEMPS DOWN ALONG THE
COAST WITH HIGHS RANGING THROUGH THE 60S.
BACKDOOR COLD FRONT APPROACHING FROM THE NORTHEAST WILL PUSH LOW
LEVEL MOISTURE INTO THE REGION FRIDAY NIGHT UNDER A FAIRLY SHARP
INVERSION. THIS WILL KEEP TEMPS UP ABOVE NORMAL THROUGH THE NIGHT
WITH OVERNIGHT LOWS RANGING THROUGH THE 40S.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE DRY FALL WEATHER WILL CONTINUE THROUGH MUCH OF THE NEXT WEEK.
ON THURSDAY MORNING...A RIDGE OF HIGH PRESSURE WAS WELL
ESTABLISHED OVER ICELAND. THIS WILL PROVE TO BE A BENEFIT TO
NORTHERN NEW ENGLAND AS THE HIGH DEVELOPS INTO A STRONG BLOCKING
PATTERN OVER THE EASTERN NORTH ATLANTIC THROUGH THE WEEKEND. THE
BROAD RIDGE OF HIGH PRESSURE CURRENTLY OVER OUR AREA HAS NOWHERE
TO GO... AND WILL STRENGTHEN IN PLACE THROUGH EARLY NEXT WEEK.
SATURDAY A LOW PUSHING THROUGH TO THE SOUTH OF THE REGION IN
COMBINATION WITH MOIST AIR FROM THE MARI TIMES WILL DRIVE A WEAK
BACK DOOR FRONT INTO COASTAL MAINE AND THE WESTERN MOUNTAINS.
EASTERLY ON-SHORE FLOW COULD LEAD TO THE DEVELOPMENT OF PERIODS OF
LIGHT DRIZZLE ON THE COAST...ALONG WITH A FEW SHOWERS IN THE
INTERIOR BUT ANY WET WEATHER IS SHORT LIVED AS THE HIGH STRENGTHENS
FOR THE END OF THE WEEKEND.
THE LONG WAVE BLOCKING PATTERN WILL EVENTUALLY BREAK
DOWN...RESULTING IN THE TROUGH OVER THE CENTRAL UNITED STATES
SHIFTING EASTWARD AND DRAGGING A COLD FRONT THROUGH NEW ENGLAND.
AS IS OFTEN THE CASE WITH BLOCKS... THERE IS LOW CONFIDENCE ON THE
TIMING OF THIS CHANGE IN THE UPPER LEVEL PATTERN... WITH EACH
MODEL RUN COMING IN PROGRESSIVELY LATER IN THE WEEK. I HAVE LEANED
ON THE WARMER AND DRIER SIDE FOR EARLY NEXT WEEK... REFLECTING THE
TREND TOWARDS A LATER BREAK DOWN OF THE TROUGH. BY WEDNESDAY THE
BLOCK WILL BREAK DOWN ALLOWING FOR THE COLD FRONT WHICH HAD BEEN
STALLED TO OUR WEST TO SWEEP THROUGH BRINGING WIDESPREAD RAIN
WEDNESDAY AND THURSDAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...VFR TONIGHT THROUGH FRIDAY NIGHT WITH IFR/LIFR
CEILINGS AND VSBY IN MORNING VALLEY FOG.
LONG TERM...
SATURDAY MORNING WILL SEE VALLEY FOG FOR LEB AND HIE WHERE CLEAR
SKIES PREVAIL. EAST OF THE MTNS... ONSHORE FLOW WILL KEEP LIFR/IFR
CEILINGS IN PLACE THROUGH THE MORNING. CIGS WILL INCREASE TO VFR
BY SATURDAY AFTERNOON AND REMAIN VFR THROUGH EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...NO FLAGS.
LONG TERM...
MOSTLY QUIET. SEAS WILL BUILD TO 5FT ON THE OUTER WATERS UNDER
EAST FLOW FOR SATURDAY...THEN DIMINISH TO 2FT AS THE HIGH
BUILDS IN. CONDITIONS WILL REMAIN CALM UNTIL SOMETIME WEDNESDAY
WHEN WINDS AND SEAS WILL BUILD TO SCA AHEAD OF THE FRONT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
418 PM EDT THU OCT 10 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 415 PM EDT THU OCT 10 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT UPR RDG
DOMINATING THE E HALF OF THE CONUS DOWNSTREAM OF TROF OVER THE W. AT
THE SFC...HI PRES EXTENDS FM NEW ENGLAND TO LOWER MI...WITH SW FLOW
ARND THIS RDG DOMINATING UPR MI. IN CONCERT WITH VERY DRY LO-MID LVL
AIR SHOWN ON THE 12Z GRB/MPX RAOBS...THE CWA IS ENJOYING ANOTHER
VERY PLEASANT OCT DAY DESPITE A STREAM OF SCT-BKN CI/CS IN THE SW
FLOW ALF BTWN THE ERN RDG/WRN TROF. MORE CLDS ARE PRESENT OVER NW MN
AND ONTARIO ALONG A STNRY FNT EXTENDING NE FM LO PRES IN THE NRN
PLAINS...BUT THESE CLDS ARE MAKING NO PROGRESS TOWARD THE CWA AND
THE DOMINATING UPR RDG. THERE WAS SOME FOG OVER INTERIOR E AND
SCENTRAL UPR MI AS WELL AS WI/LOWER MI THIS MRNG...BUT DAYTIME
HEATING/MIXING HAS DSPTD THIS FOG.
MAIN FCST CONCERNS THRU FRI REMAIN TEMPS AS WELL AS THE POTENTIAL
FOR MORE FOG TNGT AS THE UPR RDG/SFC HI PRES/DRY AIRMASS ARE FCST TO
REMAIN DOMINANT.
TNGT...EXPECT THE LOWEST MIN TEMPS TOWARD THE LO END OF GUIDANCE
OVER THE INTERIOR E AND SCENTRAL AGAIN TNGT CLOSER TO FLATTER PRES
GRADIENT AND CORE OF DRY AIR WITH PWAT FCST AOB 0.50 INCH EXCEPT
OVER THE FAR W...WHERE SHARPER PRES GRADIENT/STRONGER S WIND FARTHER
FM HI CENTER WL ALSO LIMIT THE DIURNAL TEMP FALL. EXPANDED FCST AREA
OF FOG INTO MUCH OF THE CENTRAL AWAY FM THE LK SUP SHORE WITH
UPSLOPE SSE LLVL FLOW OFF LK MI. SUSPECT THE FOG WL BECOME LOCALLY
DENSE IN THIS AREA.
FRI...AS POTENT SHRTWV LIFTS NEWD OUT OF THE WRN TROF AND THE PRES
FALLS IN THE PLAINS...THE GRADIENT OVER UPR MI WL SHARPEN THRU THE
DAY...RESULTING IN GUSTY S WINDS WITH MIXING IN THE AFTN. ALTHOUGH
THERE WL LIKELY BE AN INCRS IN HI CLDS AT LEAST OVER THE W UNDER THE
MORE DIFFLUENT SW FLOW ALF CLOSER TO THE SHRTWV IN THE PLAINS...
MODELS SHOW THE LO/MID LYRS REMAINING DRY. WITH FCST H85 TEMPS TO
12C-14C...EXPECT THE MERCURY TO TOP OUT IN THE 70S AGAIN AWAY FM THE
MODERATING INFLUENCE OF LK MI IN LLVL SE FLOW. AS HAS BEEN THE CASE
IN RECENT DAYS...THE HIEST TEMPS SHOULD OCCUR IN THE DOWNSLOPE AREAS
OVER THE W NEAR LK SUP.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 415 PM EDT THU OCT 10 2013
FRI NIGHT...MODELS HAVE MAIN SHORTWAVE AND ASSOC SFC LOW LIFTING
FROM THE NORTH DAKOTA INTO SRN MANITOBA AS COLD FRONT MOVES SLOWLY
FM CENTRAL MN IN THE EVENING INTO FAR WRN UPPER MI BY 12Z SAT. WEAK
DYNAMICS NOTED ALONG THE FRONT INITIALLY AS IT WORKS ITS WAY INTO
WRN UPPER MI LATE FRI NIGHT AS BEST Q-VECT CONV WILL PASS WELL TO
THE NW ALONG WITH MAIN SHORTWAVE AND SFC LOW. GIVEN RELATIVELY POOR
DYNAMICS...LOOK FOR ONLY ISOLD TO SCT SHRA COVERAGE ALONG THE FRONT
OVER FAR WRN UPPER MI LATE FRI NIGHT. CURRENT 20-30 PCT POPS SHOULD
COVER IT.
SAT INTO SAT EVENING...MODELS SHOW TWO SEPARATE SHORTWAVES...ONE
FROM THE CENTRAL PLAINS AND A SECOND FROM THE NORTHERN PLAINS
EJECTING INTO THE UPPER GREAT LAKES AND ALONG THE COLD FRONT AS IT
MOVES ACROSS CENTRAL AND EASTERN UPPER MI. NOT SURPRISINGLY...MODELS
SHOW RAIN COVERAGE INCREASING ALONG THE COLD FRONT AS 300K
ISENTROPIC ASCENT AND Q-VECT CONV INCREASES AHEAD OF THE SHORTWAVES.
GIVEN GOOD MODEL AGREEMENT WITH THESE DETAILS AND FCST PWAT VALUES
NEAR 200 PCT OF NORMAL WILL PROBABLY NEED BOOST POPS UP TO HIGH
LIKELY TO CATEGORICAL OVER CENTRAL AND ERN COUNTIES. WESTERN
COUNTIES SHOULD BE MOSTLY DRY SAT INTO SAT NIGHT AS COLD FRONT AND
BEST DYNAMICS WILL BE EAST.
LATE SAT EVENING INTO MONDAY...DRIER WEATHER IS IN STORE IN THE WAKE
OF THE FRONT AS BROAD SFC HIGH PRESSURE BUILDS IN FM CENTRAL CANADA
AND THE NORTHERN PLAINS. HIGHS SUNDAY WILL COOL MAINLY INTO THE 50S
CLOSER TO SEASONAL NORMALS...AS W-NW FLOW BRINGS 8H TEMPS OF 0-1C
ACROSS THE AREA. SUNDAY NIGHT SHOULD SEE GOOD RADIATIONAL COOLING
WITH SFC HIGH OVERHEAD AND SREF MODEL INDICATING PWAT VALUES AOB .50
INCH. WILL FCST TEMPS ON THE LOWER END OF MODEL GUIDANCE CLOSER TO
BIAS CORRECTED GEM VALUES. HIGH TEMPS COULD MODERATE A FEW DEGREES
ON MONDAY AS NORTHERLY FLOW WEAKENS AND VEERS EASTERLY.
TUE INTO THU...MODEL CONSISTENCY DIMINISHES OUT TOWARD THE MIDDLE OF
NEXT WEEK...ALTHOUGH GFS/ECMWF AND GEM IN GENERAL AGREEMENT WITH
SYSTEM COMING IN FOR TUESDAY. NCEP FAVORED THE ECMWF SOLN WHICH IS
SIMILAR TO GEM-NH AND SLOWER THAN GFS DUE IN LARGE PART TO DEEPER
TROUGHING EXPECTED OVER SW CONUS AND BLOCKING PATTERN SETTING UP
OVER THE EASTERN PACIFIC. FOLLOWING THE SLOWER ECMWF SOLN...BROUGHT
IN HIGHER CHC TO LIKELY POPS OVER THE WRN COUNTIES MON NIGHT WITH
INCREASING DEEP LYR Q-VECT CONV AND THEN SPREAD HIGH CHC TO LIKELY
POPS ACROSS THE CWA ON TUE INTO TUE EVENING AS SFC LOW TRACKS JUST
SOUTH OF THE AREA. MAINTAINED SOME HIGHER CHC POPS FOR WED AS
COMMA-HEAD MOISTURE ON THE BACKSIDE OF THE LOW PRESSURE SYSTEM COULD
LINGER OVER INTO THE AREA. BOTH THE 12Z GFS AND ECMWF SUGGEST
SHORTWAVE RDGG AND DRIER CONDITIONS WED NIGHT IN WAKE OF DEPARTING
STORM SYSTEM BEFORE ANOTHER SHORTWAVE MOVES IN FROM THE PLAINS ON
THU BRINGING ANOTHER CHC OF SHRA. MODELS NOT SHOWING VERY GOOD
CONSISTENCY WITH DETAILS OR STRENGTH WITH THU SYSTEM...SO EXPECT
THERE WILL BE PLENTY OF FINE TUNING OF FCST YET TO COME FOR LATE NEXT
WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 121 PM EDT THU OCT 10 2013
WITH DRY HI PRES DOMINATING...EXPECT VFR CONDITIONS TO BE THE RULE
THIS TAF PERIOD. THE EXCEPTION WL BE LATE TNGT INTO FRI MRNG AT SAW.
WITH A LGT UPSLOPE SSE WIND OFF LK MI UNDER LINGERING MID LVL DRY
AIR...OPTED TO INCLUDE A FCST OF FOG/LIFR CONDITIONS FOR THAT
LOCATION. DOWNSLOPE NATURE OF THIS FLOW AT CMX/IWD SHOULD LIMIT THE
POTENTIAL FOR THIS FOG AT THOSE SITES. A GUSTY S WIND WL DVLP LATER
IN THE TAF PERIOD ON FRI AFTN AT IWD WITH ONSET OF DAYTIME HEATING/
MIXING UNDER TIGHTENING PRES GRADIENT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 415 PM EDT THU OCT 10 2013
LIGHT E-SE WINDS WITH HI PRES DOMINATING WILL VEER TO THE S AND
INCREASE UP TO 25 KTS ON FRI INTO SAT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN THE HI CENTER TO THE E AND A DEVELOPING
LO IN THE PLAINS. THIS LOW WILL MOVE NE THRU SCENTRAL CANADA INTO
HUDSON BAY OVER THE WEEKEND...DRAGGING A COLD FRONT ACROSS LAKE
SUPERIOR ON SAT. EXPECT A WIND SHIFT TO THE W-NW BEHIND THIS FROPA
SAT NIGHT/SUN AND DIMINISHING WINDS AS HI PRES MOVES INTO THE AREA.
WINDS ON MON INTO TUE WILL SHIFT TO THE E-NE AS THE HI RETREATS INTO
CANADA AND A LO PRES APPROACHES FROM THE PLAINS. WINDS OVER THE
WESTERN LAKE MAY INCREASE UP TO 25 KTS BY TUE WITH FAVORABLE TERRAIN
ENHANCEMENT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
330 AM EDT THU OCT 10 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 239 PM EDT WED OCT 9 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
OVER THE E HALF OF THE CONUS DOWNWIND OF TROF OVER THE W. AT THE
SFC...HI PRES IS SITUATED OVER NEW ENGLAND...WITH WEAKENING LO PRES
OVER NW ONTARIO ASSOCIATED WITH CNDN SHRTWV RIDING OVER UPR RDG. THE
CWA IS DOMINATED BY THE LLVL SW FLOW BTWN THESE FEATURES. BUT
BECAUSE THE SFC LO IS WEAKENING WITH PRES RISES OBSVD OVER THE SFC
LO...THE GRADIENT IS WEAKENING STEADILY WITH TIME. SO SW WINDS THIS
AFTN ARE NOT AS GUSTY AS YDAY DESPITE DAYTIME HEATING/MIXING.
OTRW...THE LOCAL AND UPSTREAM 12Z RAOBS SHOW A RELATIVELY DRY LLVL
AIRMASS...SO THERE IS NOTHING MORE THAN PATCHY HI CLDS TO THE SW OF
SOME THICKER CLDS IN ONTARIO ASSOCIATED WITH THE LO WELL N OF THE
BORDER. THE ONLY EXCEPTION WAS A BIT OF LO CLD THAT DVLPD DOWNWIND
OF LK MI NEAR MANISTIQUE WHERE THE SW FLOW OFF THE WATER HAS LIFTED
SFC DEWPTS AS HI AS 55 TO 60. WITH A RIBBON OF H85 TEMPS UP TO 15C
STREAMING INTO THE WRN CWA IN THE SW FLOW...TEMPS ARE RUNNING WELL
ABV NORMAL EARLY THIS AFTN WITH READINGS AS HI AS THE LO 70S AT SOME
PLACES AWAY FM THE MODERATING INFLUENCE OF LK MI.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON TEMPS WITH
DRY...ACYC SW FLOW ARND SFC HI PRES STRETCHING FM THE NE COAST INTO
THE GREAT LKS FCST TO DOMINATE THRU THU.
TNGT...EXPECT LO TEMPS TNGT TO FALL A BIT MORE THAN LAST NGT WITH
DRY AIR LINGERING UNDER WEAKENING PRES GRADIENT/SW FLOW AS HIER PRES
SLOWLY EXPANDS TO THE W. EXPECT THE LOWEST MIN TEMPS OVER THE
INTERIOR SCENTRAL AND E...CLOSER TO THE WEAKEST GRADIENT/LOWER PWATS
AOB 0.5 INCH. WITH THESE IMPROVED RADIATIONAL COOLING CONDITIONS
OVER HIER DEWPTS OBSVD THIS AFTN...EXPECT PATCHY FOG IN THESE AREAS.
THU...LOOKS LIKE ANOTHER PLEASANT OCT DAY WITH DRY SW FLOW FCST TO
DOMINATE AND LEAD TO MOSUNNY CONDITIONS. H85 TEMPS ARE FCST NEAR
14C...ALMOST THE SAME AS TDAY...SO EXPECT MAX TEMPS TO BE SIMILAR TO
THIS AFTN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT THU OCT 10 2013
UPPER AIR PATTERN WILL BE A TROUGH AND CLOSED LOW OVER THE NORTHERN
PLAINS 12Z FRI WITH THE LOW HEADING NE AND THE TROUGH MOVING INTO
THE UPPER GREAT LAKES ON SAT. THIS TROUGH MOVES THROUGH SAT NIGHT.
NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA FRI
NIGHT AND SAT AND GFS SHOWS THIS AS WELL. SINCE VERY LITTLE MOISTURE
IS THERE TO WORK WITH FOR FRI NIGHT...SLIGHT CHANCE POPS FOR THE
WEST HALF LOOK GOOD. ON SATURDAY...A BIT MORE MOISTURE COMES IN AND
WENT WITH CHANCE POPS ACROSS THE CENTRAL CWA. THE PCPN MOVES OUT SAT
NIGHT AND LOW CHANCE TO CHANCE POPS OVER THE EAST STILL LOOK GOOD.
AS FOR TEMPERATURES...MADE A FEW ADJUSTMENTS HERE AND THERE TAKING
INTO ACCOUNT SOME DOWNSLOPE AREAS WITH WEST OR SOUTH WINDS.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
WESTERN U.S. AND A SHORTWAVE TROUGH OVER THE UPPER GREAT LAKES 12Z
SUN. THE TROUGH OVER THE WESTERN U.S. DIGS INTO THE DESERT SW 12Z
MON AND THIS TROUGH MOVES INTO THE PLAINS 12Z TUE AND INTO THE UPPER
GREAT LAKES 12Z WED. TEMPERATURES FALL TO BELOW NORMAL THIS PERIOD
STARTING TUE. THERE WILL BE A CHANCE OF RAIN STARTING MON NIGHT
LASTING INTO WED WITH A STORM SYSTEM PASSING BY TO THE SOUTH AND
CHANCE POPS COVERS THIS FOR NOW...BUT THIS IS STARTING TO LOOK LIKE
A GOOD RAIN PRODUCER AND FEELING IS FUTURE SHIFTS WILL PROBABLY
HAVE TO BOOST POPS AS THIS APPROACHES THE AREA. IT WILL BE DRY
SUNDAY THROUGH MONDAY AND NOTICEABLY COOLER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM EDT THU OCT 10 2013
DRY HIGH PRESSURE WILL BRING VFR CONDITIONS TO THE TAF SITES THIS
FCST PERIOD. THE ONE EXCEPTION MAY BE SAW LATE TONIGHT OR EARLY
THU...WHERE SOME FOG COULD DEVELOP. WITH THE LOW LEVEL FLOW MORE SSW
COMPARED TO SSE OFF LAKE MI...PROBABILITY OF FOG FORMATION WAS LOW
AND NOT INCLUDED IN THE TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 312 AM EDT THU OCT 10 2013
LAKE SUPERIOR WILL REMAIN IN BETWEEN HIGH PRESSURE TO OUR E AND LOW
PRESSURE TO THE W. THE RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE
GREAT LAKES AND NEW ENGLAND STATES WILL SLOWLY BE REPLACED BY LOW
PRESSURE NEARING FROM THE SOUTHWEST. LOW PRESSURE OFF THE COLORADO
ROCKIES THIS AFTERNOON WILL LIFT ACROSS THE DAKOTAS FRIDAY...BEFORE
SURGING INTO HUDSON BAY SATURDAY NIGHT AND SUNDAY. THIS WILL ALLOW A
TROUGH TO PUSH ACROSS LAKE SUPERIOR SATURDAY AND SATURDAY NIGHT.
AHEAD OF THE TROUGH...S GUSTS OF 25-30KTS WILL BE POSSIBLE FRIDAY
NIGHT THROUGH SATURDAY. EXPECT LARGE HIGH PRESSURE OVER THE PLAINS
STATES TO QUICKLY PUSH ACROSS THE UPPER GREAT LAKES SUNDAY AND
MONDAY. LOOKING FARTHER OUT...MID WEEK LOOKS COOL AND BREEZY.
ALTHOUGH THERE IS SOME VARIABILITY IN TIMING AND INTENSITY...MORE
20-30KT WINDS IF NOT GALE FORCE GUSTS WILL BE POSSIBLE WEDNESDAY
INTO THURSDAY AS LOW PRESSURE CROSSES THE REGION FROM THE SW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
313 AM EDT THU OCT 10 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 239 PM EDT WED OCT 9 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
OVER THE E HALF OF THE CONUS DOWNWIND OF TROF OVER THE W. AT THE
SFC...HI PRES IS SITUATED OVER NEW ENGLAND...WITH WEAKENING LO PRES
OVER NW ONTARIO ASSOCIATED WITH CNDN SHRTWV RIDING OVER UPR RDG. THE
CWA IS DOMINATED BY THE LLVL SW FLOW BTWN THESE FEATURES. BUT
BECAUSE THE SFC LO IS WEAKENING WITH PRES RISES OBSVD OVER THE SFC
LO...THE GRADIENT IS WEAKENING STEADILY WITH TIME. SO SW WINDS THIS
AFTN ARE NOT AS GUSTY AS YDAY DESPITE DAYTIME HEATING/MIXING.
OTRW...THE LOCAL AND UPSTREAM 12Z RAOBS SHOW A RELATIVELY DRY LLVL
AIRMASS...SO THERE IS NOTHING MORE THAN PATCHY HI CLDS TO THE SW OF
SOME THICKER CLDS IN ONTARIO ASSOCIATED WITH THE LO WELL N OF THE
BORDER. THE ONLY EXCEPTION WAS A BIT OF LO CLD THAT DVLPD DOWNWIND
OF LK MI NEAR MANISTIQUE WHERE THE SW FLOW OFF THE WATER HAS LIFTED
SFC DEWPTS AS HI AS 55 TO 60. WITH A RIBBON OF H85 TEMPS UP TO 15C
STREAMING INTO THE WRN CWA IN THE SW FLOW...TEMPS ARE RUNNING WELL
ABV NORMAL EARLY THIS AFTN WITH READINGS AS HI AS THE LO 70S AT SOME
PLACES AWAY FM THE MODERATING INFLUENCE OF LK MI.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON TEMPS WITH
DRY...ACYC SW FLOW ARND SFC HI PRES STRETCHING FM THE NE COAST INTO
THE GREAT LKS FCST TO DOMINATE THRU THU.
TNGT...EXPECT LO TEMPS TNGT TO FALL A BIT MORE THAN LAST NGT WITH
DRY AIR LINGERING UNDER WEAKENING PRES GRADIENT/SW FLOW AS HIER PRES
SLOWLY EXPANDS TO THE W. EXPECT THE LOWEST MIN TEMPS OVER THE
INTERIOR SCENTRAL AND E...CLOSER TO THE WEAKEST GRADIENT/LOWER PWATS
AOB 0.5 INCH. WITH THESE IMPROVED RADIATIONAL COOLING CONDITIONS
OVER HIER DEWPTS OBSVD THIS AFTN...EXPECT PATCHY FOG IN THESE AREAS.
THU...LOOKS LIKE ANOTHER PLEASANT OCT DAY WITH DRY SW FLOW FCST TO
DOMINATE AND LEAD TO MOSUNNY CONDITIONS. H85 TEMPS ARE FCST NEAR
14C...ALMOST THE SAME AS TDAY...SO EXPECT MAX TEMPS TO BE SIMILAR TO
THIS AFTN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 239 PM EDT WED OCT 9 2013
AT 00Z FRI...THERE WILL BE AN UPPER RIDGE OVER THE CWA THAT WILL
GIVE WAY TO A LOW PRESSURE SYSTEM MOVING FROM NE AT 12Z FRI TO FAR
SRN MANITOBA AT 12Z SAT. FRI WILL BE QUIET WITH NO PRECIP EXPECTED
DUE TO THE RIDGE BEING OVERHEAD...BUT WITH 850MB TEMPS AROUND
14C...TEMPS WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE 60S AND 70S.
AFTER 12Z SAT...MODEL DISAGREEMENT ON THE TIMING/TRACK OF THE SYSTEM
IS MORE UNCERTAIN. THE 12Z/09 GFS KEEPS THE LOW MOVING RAPIDLY NNE
TO HUDSON BAY BY 00Z SUN...WHILE 00Z/09 ECMWF HANGS THE LOW OVER
ONTARIO WHILE WEAKENING...AND FINALLY MOVING TO JAMES BAY AROUND 06Z
MON. THE 00Z/09 GEM SOLUTION IS BETWEEN THE GFS AND ECMWF WITH
TIMING/TRACK. PRECIP OVER THE CWA FROM THIS SYSTEM WILL MAINLY
RESULT FROM THE ASSOCIATED COLD FRONT MOVING THROUGH. OF
COURSE...THERE ARE ALSO SOME TIMING DIFFERENCES WITH TIMING OF
FROPA. THE GFS MOVES THE FRONT FROM THE WRN U.P. AT 18Z SAT TO THE
ERN CWA AROUND 06Z SUN...WITH THE ECMWF BEING AROUND 6 HOURS SLOWER.
THE GEM MATCHES UP PRETTY CLOSE TO THE GFS WITH FROPA TIMING. THERE
MAY BE SOME SHOWERS OVER THE WRN CWA FRI NIGHT AS THE LOW MOVES TO
THE W...BUT OTHERWISE MOST PRECIP WITH THE FRONT SHOULD BE OVER THE
CENTRAL AND ERN CWA WHERE THE FRONT WILL INTERACT WITH BETTER
INSTABILITY AND MAY BE BACKED UP BY AN UPPER SHORTWAVE TROUGH. WILL
NOT GO COMPLETELY DRY OVER THE W...BUT WILL HAVE HIGHEST POPS
CENTRAL AND E AND TIMING CLOSER THE GFS/GEM SOLUTIONS.
COLDER AIR WILL FILTER IN BEHIND THE SYSTEM...WITH 850MB TEMPS
FALLING INTO THE LOW SINGLE DIGITS ABOVE AND MAYBE JUST BELOW ZERO
BY LATE SUN/SUN NIGHT. THIS IS WHERE THE MODEL DIFFERENCES BECOME
MORE SIGNIFICANT AS THE GFS AND GEM USHER IN DRY HIGH PRESSURE FOR SUN
NIGHT WHILE THE ECMWF SOLUTION WITH THE LAGGING LOW WILL KEEP MORE
CLOUDS OVERHEAD. WITH THE CLOUDIER ECMWF SOLUTION...LOW TEMPS SUN
NIGHT SHOULD FALL INTO THE UPPER 30S TO MID 40S. THE LESS CLOUDY
SOLUTIONS WOULD LIKELY RESULT IN A DECENT FREEZE AWAY FROM THE
IMMEDIATE SHORES OF THE GREAT LAKES. WILL GO WITH A MIDDLE OF THE
ROAD APPROACH AND KEEP CONSENSUS LOW TEMPS FROM THE MID 30S TO MID
40S.
THINGS BECOME MORE UNCERTAIN MON THROUGH NEXT WED AS MODELS CONTINUE
TO POINT TO A MAJOR PATTERN CHANGE FROM THIS PORTION OF THE COUNTRY.
MODELS GENERALLY SHOW MUCH INCREASED UPPER TROUGHING OVER THE ERN
HAVE OF THE CONUS...RESULTING IN COLDER TEMPERATURES AND GREATER
STRENGTH/FREQUENCY OF SYSTEMS MOVING THROUGH THE REGION. DEFINITELY
LOOKS COLDER WITH TEMPS EVEN FALLING TO BELOW NORMAL VALUES. POPS
ARE FAR MORE UNCERTAIN AS SYSTEM STRENGTH/TRACK IS FAR FROM CERTAIN.
TEMPS DO NOT LOOK QUITE COLD ENOUGH TO ADD MIXED PRECIP TO THE
FORECAST...ESPECIALLY GIVEN UNCERTAINTY INVOLVED. USED A CONSENSUS
OF MODEL GUIDANCE FOR THIS PORTION OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM EDT THU OCT 10 2013
DRY HIGH PRESSURE WILL BRING VFR CONDITIONS TO THE TAF SITES THIS
FCST PERIOD. THE ONE EXCEPTION MAY BE SAW LATE TONIGHT OR EARLY
THU...WHERE SOME FOG COULD DEVELOP. WITH THE LOW LEVEL FLOW MORE SSW
COMPARED TO SSE OFF LAKE MI...PROBABILITY OF FOG FORMATION WAS LOW
AND NOT INCLUDED IN THE TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 312 AM EDT THU OCT 10 2013
LAKE SUPERIOR WILL REMAIN IN BETWEEN HIGH PRESSURE TO OUR E AND LOW
PRESSURE TO THE W. THE RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE
GREAT LAKES AND NEW ENGLAND STATES WILL SLOWLY BE REPLACED BY LOW
PRESSURE NEARING FROM THE SOUTHWEST. LOW PRESSURE OFF THE COLORADO
ROCKIES THIS AFTERNOON WILL LIFT ACROSS THE DAKOTAS FRIDAY...BEFORE
SURGING INTO HUDSON BAY SATURDAY NIGHT AND SUNDAY. THIS WILL ALLOW A
TROUGH TO PUSH ACROSS LAKE SUPERIOR SATURDAY AND SATURDAY NIGHT.
AHEAD OF THE TROUGH...S GUSTS OF 25-30KTS WILL BE POSSIBLE FRIDAY
NIGHT THROUGH SATURDAY. EXPECT LARGE HIGH PRESSURE OVER THE PLAINS
STATES TO QUICKLY PUSH ACROSS THE UPPER GREAT LAKES SUNDAY AND
MONDAY. LOOKING FARTHER OUT...MID WEEK LOOKS COOL AND BREEZY.
ALTHOUGH THERE IS SOME VARIABILITY IN TIMING AND INTENSITY...MORE
20-30KT WINDS IF NOT GALE FORCE GUSTS WILL BE POSSIBLE WEDNESDAY
INTO THURSDAY AS LOW PRESSURE CROSSES THE REGION FROM THE SW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1208 AM EDT THU OCT 10 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 239 PM EDT WED OCT 9 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
OVER THE E HALF OF THE CONUS DOWNWIND OF TROF OVER THE W. AT THE
SFC...HI PRES IS SITUATED OVER NEW ENGLAND...WITH WEAKENING LO PRES
OVER NW ONTARIO ASSOCIATED WITH CNDN SHRTWV RIDING OVER UPR RDG. THE
CWA IS DOMINATED BY THE LLVL SW FLOW BTWN THESE FEATURES. BUT
BECAUSE THE SFC LO IS WEAKENING WITH PRES RISES OBSVD OVER THE SFC
LO...THE GRADIENT IS WEAKENING STEADILY WITH TIME. SO SW WINDS THIS
AFTN ARE NOT AS GUSTY AS YDAY DESPITE DAYTIME HEATING/MIXING.
OTRW...THE LOCAL AND UPSTREAM 12Z RAOBS SHOW A RELATIVELY DRY LLVL
AIRMASS...SO THERE IS NOTHING MORE THAN PATCHY HI CLDS TO THE SW OF
SOME THICKER CLDS IN ONTARIO ASSOCIATED WITH THE LO WELL N OF THE
BORDER. THE ONLY EXCEPTION WAS A BIT OF LO CLD THAT DVLPD DOWNWIND
OF LK MI NEAR MANISTIQUE WHERE THE SW FLOW OFF THE WATER HAS LIFTED
SFC DEWPTS AS HI AS 55 TO 60. WITH A RIBBON OF H85 TEMPS UP TO 15C
STREAMING INTO THE WRN CWA IN THE SW FLOW...TEMPS ARE RUNNING WELL
ABV NORMAL EARLY THIS AFTN WITH READINGS AS HI AS THE LO 70S AT SOME
PLACES AWAY FM THE MODERATING INFLUENCE OF LK MI.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON TEMPS WITH
DRY...ACYC SW FLOW ARND SFC HI PRES STRETCHING FM THE NE COAST INTO
THE GREAT LKS FCST TO DOMINATE THRU THU.
TNGT...EXPECT LO TEMPS TNGT TO FALL A BIT MORE THAN LAST NGT WITH
DRY AIR LINGERING UNDER WEAKENING PRES GRADIENT/SW FLOW AS HIER PRES
SLOWLY EXPANDS TO THE W. EXPECT THE LOWEST MIN TEMPS OVER THE
INTERIOR SCENTRAL AND E...CLOSER TO THE WEAKEST GRADIENT/LOWER PWATS
AOB 0.5 INCH. WITH THESE IMPROVED RADIATIONAL COOLING CONDITIONS
OVER HIER DEWPTS OBSVD THIS AFTN...EXPECT PATCHY FOG IN THESE AREAS.
THU...LOOKS LIKE ANOTHER PLEASANT OCT DAY WITH DRY SW FLOW FCST TO
DOMINATE AND LEAD TO MOSUNNY CONDITIONS. H85 TEMPS ARE FCST NEAR
14C...ALMOST THE SAME AS TDAY...SO EXPECT MAX TEMPS TO BE SIMILAR TO
THIS AFTN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 239 PM EDT WED OCT 9 2013
AT 00Z FRI...THERE WILL BE AN UPPER RIDGE OVER THE CWA THAT WILL
GIVE WAY TO A LOW PRESSURE SYSTEM MOVING FROM NE AT 12Z FRI TO FAR
SRN MANITOBA AT 12Z SAT. FRI WILL BE QUIET WITH NO PRECIP EXPECTED
DUE TO THE RIDGE BEING OVERHEAD...BUT WITH 850MB TEMPS AROUND
14C...TEMPS WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE 60S AND 70S.
AFTER 12Z SAT...MODEL DISAGREEMENT ON THE TIMING/TRACK OF THE SYSTEM
IS MORE UNCERTAIN. THE 12Z/09 GFS KEEPS THE LOW MOVING RAPIDLY NNE
TO HUDSON BAY BY 00Z SUN...WHILE 00Z/09 ECMWF HANGS THE LOW OVER
ONTARIO WHILE WEAKENING...AND FINALLY MOVING TO JAMES BAY AROUND 06Z
MON. THE 00Z/09 GEM SOLUTION IS BETWEEN THE GFS AND ECMWF WITH
TIMING/TRACK. PRECIP OVER THE CWA FROM THIS SYSTEM WILL MAINLY
RESULT FROM THE ASSOCIATED COLD FRONT MOVING THROUGH. OF
COURSE...THERE ARE ALSO SOME TIMING DIFFERENCES WITH TIMING OF
FROPA. THE GFS MOVES THE FRONT FROM THE WRN U.P. AT 18Z SAT TO THE
ERN CWA AROUND 06Z SUN...WITH THE ECMWF BEING AROUND 6 HOURS SLOWER.
THE GEM MATCHES UP PRETTY CLOSE TO THE GFS WITH FROPA TIMING. THERE
MAY BE SOME SHOWERS OVER THE WRN CWA FRI NIGHT AS THE LOW MOVES TO
THE W...BUT OTHERWISE MOST PRECIP WITH THE FRONT SHOULD BE OVER THE
CENTRAL AND ERN CWA WHERE THE FRONT WILL INTERACT WITH BETTER
INSTABILITY AND MAY BE BACKED UP BY AN UPPER SHORTWAVE TROUGH. WILL
NOT GO COMPLETELY DRY OVER THE W...BUT WILL HAVE HIGHEST POPS
CENTRAL AND E AND TIMING CLOSER THE GFS/GEM SOLUTIONS.
COLDER AIR WILL FILTER IN BEHIND THE SYSTEM...WITH 850MB TEMPS
FALLING INTO THE LOW SINGLE DIGITS ABOVE AND MAYBE JUST BELOW ZERO
BY LATE SUN/SUN NIGHT. THIS IS WHERE THE MODEL DIFFERENCES BECOME
MORE SIGNIFICANT AS THE GFS AND GEM USHER IN DRY HIGH PRESSURE FOR SUN
NIGHT WHILE THE ECMWF SOLUTION WITH THE LAGGING LOW WILL KEEP MORE
CLOUDS OVERHEAD. WITH THE CLOUDIER ECMWF SOLUTION...LOW TEMPS SUN
NIGHT SHOULD FALL INTO THE UPPER 30S TO MID 40S. THE LESS CLOUDY
SOLUTIONS WOULD LIKELY RESULT IN A DECENT FREEZE AWAY FROM THE
IMMEDIATE SHORES OF THE GREAT LAKES. WILL GO WITH A MIDDLE OF THE
ROAD APPROACH AND KEEP CONSENSUS LOW TEMPS FROM THE MID 30S TO MID
40S.
THINGS BECOME MORE UNCERTAIN MON THROUGH NEXT WED AS MODELS CONTINUE
TO POINT TO A MAJOR PATTERN CHANGE FROM THIS PORTION OF THE COUNTRY.
MODELS GENERALLY SHOW MUCH INCREASED UPPER TROUGHING OVER THE ERN
HAVE OF THE CONUS...RESULTING IN COLDER TEMPERATURES AND GREATER
STRENGTH/FREQUENCY OF SYSTEMS MOVING THROUGH THE REGION. DEFINITELY
LOOKS COLDER WITH TEMPS EVEN FALLING TO BELOW NORMAL VALUES. POPS
ARE FAR MORE UNCERTAIN AS SYSTEM STRENGTH/TRACK IS FAR FROM CERTAIN.
TEMPS DO NOT LOOK QUITE COLD ENOUGH TO ADD MIXED PRECIP TO THE
FORECAST...ESPECIALLY GIVEN UNCERTAINTY INVOLVED. USED A CONSENSUS
OF MODEL GUIDANCE FOR THIS PORTION OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM EDT THU OCT 10 2013
DRY HIGH PRESSURE WILL BRING VFR CONDITIONS TO THE TAF SITES THIS
FCST PERIOD. THE ONE EXCEPTION MAY BE SAW LATE TONIGHT OR EARLY
THU...WHERE SOME FOG COULD DEVELOP. WITH THE LOW LEVEL FLOW MORE SSW
COMPARED TO SSE OFF LAKE MI...PROBABILITY OF FOG FORMATION WAS LOW
AND NOT INCLUDED IN THE TAF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 239 PM EDT WED OCT 9 2013
EXPECT S TO SW WINDS UP TO 20 KTS THRU THU NIGHT TO INCREASE TO UP
TO 25 KTS ON FRI INTO SAT AS THE PRES GRADIENT TIGHTENS BETWEEN HI
PRES OVER THE EASTERN CONUS AND AN APPROACHING COLD FRONT. BEHIND
THIS FRONTAL PASSAGE ON SAT...LOOK FOR A WIND SHIFT TO THE W-NW
BEFORE WINDS SLOWLY VEER TO THE N BY MON AHEAD OF AN APPROACHING HI
PRES CENTER. WINDS WILL BE AS HI AS 20-25 KTS ON SAT NIGHT/SUN
FOLLOWING THIS FROPA...BUT THESE WINDS SHOULD DIMINISH UNDER 20 KTS
BY MON AS THE HI PRES/WEAKER PRES GRADIENT MOVES NEARBY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
649 PM CDT FRI OCT 11 2013
.MESOSCALE DISCUSSION...
ISSUED AT 649 PM CDT FRI OCT 11 2013
SHOWERS AND THUNDERSTORMS CONTINUED TO MOVE THROUGH NORTHEAST
MINNESOTA AND PORTIONS OF NORTHERN WISCONSIN EARLY THIS EVENING.
THE THUNDERSTORMS HAVE NOT BEEN VERY STRONG THIS EVENING...WITH
A BRIEF PERIOD OF HEAVY RAIN AND SOME GUSTY WINDS THE MAIN THREATS
WITH THIS FIRST BATCH OF SHOWERS/STORMS.
ANOTHER LINE OF STRONGER SHOWERS/THUNDERSTORMS WERE ASSOCIATED WITH THE
FRONTAL BOUNDARY. THESE WERE ARCING FROM NEAR KMVX INTO SOUTHWEST
MINNESOTA. SPC MESOANALYSIS SHOWED BEST THE 0-3KM CAPE OF
50-70J/KG OVER SOUTHEAST NORTH DAKOTA INTO EXTREME WEST CENTRAL MINNESOTA
AS OF 23Z. THESE STORMS WERE MOVING NORTHEAST AND SHOULD IMPACT
OUR SOUTHWEST CWA AS EARLY AS 800 PM. WITH LOSS OF HEATING...WE DO
EXPECT SOME DECREASE IN INTENSITY...BUT STILL A STRONG
THUNDERSTORM IS POSSIBLE IN THE BRAINERD LAKES...PINE
RIVER...LONGVILLE...WALKER AREAS THROUGH 9 PM. THE NMM-WRF
SUGGESTS THIS LINE OF STORMS WILL MAINTAIN IT`S STRENGTH AS IT
MOVES FURTHER EAST INTO FAR EASTERN MINNESOTA BY LATE
EVENING...THEN WEAKEN. SEVERE THREAT WILL BE LOW ACROSS OUR CWA
DUE TO LACK OF INSTABILITY. IMPRESSIVE SHEAR DOES EXIST THOUGH.
WE`LL CONTINUE TO WATCH THE STORMS THIS EVENING AND ISSUE
STATEMENTS AS THESE STORMS NEAR OUR CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 301 PM CDT FRI OCT 11 2013
AT 300PM/2000Z...THERE WAS A STRONG AND STACKED LOW PRESSURE SYSTEM
LIFTING NNE THROUGH NORTH CENTRAL SOUTH DAKOTA. A STRONG COLD
FRONT STRETCHED FROM THE LOW THROUGH CENTRAL SOUTH
DAKOTA...CENTRAL NEBRASKA...AND CENTRAL KANSAS. THIS STORM SYSTEM
HAD MULTIPLE BANDS OF SHOWERS AND STORMS ACROSS THE
DAKOTAS...WESTERN MINNESOTA...AND SOUTHERN MANITOBA. ONE BAND OF
SHOWERS AND STORMS STRETCHED FROM NE NORTH DAKOTA THROUGH NW AND
WESTERN MINNESOTA. THE BAND WAS STEADILY MOVING NORTH AND SLOWLY
EAST. CLOUDY TO MOSTLY CLOUDY SKIES COVERED MUCH OF THE DAKOTAS
AND WESTERN AND SOUTHERN MINNESOTA...WHILE EASTERN MINNESOTA AND
WISCONSIN STILL HAD PARTLY TO MOSTLY SUNNY SKIES. THE NORTHLAND
HAD SE WINDS OF ABOUT 10 TO 20 MPH WITH GUSTS UP TO 35 MPH IN SOME
AREAS. TEMPERATURES WERE IN THE LOWER 70S ACROSS MOST OF THE
REGION...EXCEPT FOR 60S OVER THE ARROWHEAD AND UPPER 70S NEAR
BAYFIELD PENINSULA. DEW POINT TEMPERATURES WERE IN THE UPPER 40S
TO LOWER 50S.
TONIGHT...THE STRONG LOW PRESSURE SYSTEM WILL LIFT THROUGH EASTERN
NORTH DAKOTA THIS EVENING AND SOUTHERN MANITOBA LATE TONIGHT.
THE STRONG COLD FRONT WILL MOVE THROUGH THE NORTHLAND OVERNIGHT.
THE BAND OF SHOWERS AND STORMS CURRENTLY ACROSS WESTERN MINNESOTA
WILL WORK ITS WAY THROUGH AT LEAST THE WESTERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING BEFORE BEGINNING TO DISSIPATE.
ANOTHER BAND OF SHOWERS AND STORMS WILL LIKELY FOLLOW IN ITS WAKE
A FEW HOURS BEHIND THE FIRST BAND. I FORECAST HIGH CHANCES OF PCPN
FOR THE SW FORECAST AREA SINCE IT WILL LIKELY BE AFFECTED...AND WE
MAY NEED TO INCREASE PCPN CHANCES OVER OTHER PARTS OF THE FORECAST
AREA AS THE BAND OF SHOWERS AND STORMS BEGINS TO MOVE INTO THE
NORTHERN AND CENTRAL FORECAST AREA. THESE SHOWERS AND STORMS COULD
PRODUCE VERY GUSTY WINDS...PERHAPS AS HIGH AS 45 MPH...DUE TO THE
STRONG FLOW ALOFT IN THE MIXING LAYER AND JUST ABOVE THE MIXING
LAYER. AND DESPITE THE DECOUPLING THAT WILL OCCUR THIS
EVENING...THE SHOWERS COULD STILL MIX DOWN THESE STRONG GUSTS FOR
A WHILE THIS EVENING. STORM PREDICTION CENTER CONTINUES TO HAVE A
SLIGHT RISK OF SEVERE STORMS ACROSS THE FAR SW FORECAST AREA. THIS
IS DUE TO THE STRONG LOW LEVEL SHEAR AND STRONG LOW LEVEL FLOW
WHICH COULD PRODUCE DAMAGING WINDS AND ISOLATED TORNADOES WITH
STORMS...BUT THE LIMITING FACTOR IS CAPE...ESPECIALLY SURFACE
BASED CAPE. OVERNIGHT LOWS SHOULD BE IN THE UPPER 40S TO MID 50S.
SATURDAY...THE NORTHLAND WILL HAVE A CLOUDY AND WINDY DAY IN THE
WAKE OF THE COLD FRONT AS A POTENT SHORTWAVE LIFTS THROUGH THE
NORTHLAND AND SURROUNDING REGION. THE SW WINDS OF 15 TO 20 MPH
WILL GUST UP TO 30 MPH. THE COLD AIR ALOFT AND STRONG MIXING WILL
HELP GENERATE THICK CLOUD COVER AND RAIN SHOWERS. I LOWERED THE
HIGH TEMPERATURES TO THE LOW 50S ACROSS NE MINNESOTA AND THE UPPER
50S TO NEAR 60 DEGREES ACROSS NW WISCONSIN. WE MAY NEED TO LOWER
THE TEMPERATURES A BIT MORE DEPENDING ON HOW QUICKLY THE HEAVY
CLOUD COVER DEVELOPS AND/OR MOVES INTO THE NORTHLAND.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 301 PM CDT FRI OCT 11 2013
AN UPPER LEVEL TROUGH WILL SWING ACROSS THE NORTHLAND SATURDAY
NIGHT...RESULTING IN SOME EVENING SHOWERS ACROSS THE REGION. THE
GUSTY SOUTHWEST TO WEST WINDS WILL ALSO CONTINUE INTO THE NIGHT
BEFORE SUBSIDING SOME OVERNIGHT. SKIES WILL GRADUALLY START TO
CLEAR LATER IN THE NIGHT FROM WEST TO EAST. THE NEXT SYSTEM WILL
ALREADY START TO AFFECT THE REGION LATER SUNDAY...AS HIGH AND MID
CLOUDS INCREASE ACROSS AT LEAST THE SW PART OF THE REGION. THE
MODELS INDICATE SOME PRECIPITATION MAY MAKE IT INTO THE CWA LATER
SUNDAY NIGHT...ESPECIALLY IN THE BRAINERD LAKES REGION. BEYOND
THAT...IT IS SHAPING UP TO BE A VERY WET PERIOD MONDAY INTO
WEDNESDAY. THERE ARE SOME DIFFERENCES AMONGST THE DETERMINISTIC
MODELS...ESPECIALLY WITH RESPECT TO TIMING AND SPEED OF THE
SYSTEM...BUT OVERALL IT LOOKS LIKE IT WILL BE A WET EARLY TO
MIDDLE PART OF THE UPCOMING WORK WEEK. TEMPERATURES WILL BE KEPT
COOLER BY THE RAIN AND CLOUDS. THE GFS AND ECMWF DISAGREE TO SOME
EXTENT DURING THE LATTER PART OF THE WORK WEEK AS WELL...BUT BOTH
MODELS MAINTAIN SOME SORT OF UNSETTLED WEATHER WITH SOME SCATTERED
SHOWERS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 649 PM CDT FRI OCT 11 2013
AN AREA OF SHOWERS/THUNDERSTORMS WERE MOVING THROUGH NORTHERN
MINNESOTA AND PORTIONS OF NORTHWEST WISCONSIN EARLY THIS
EVENING...AND WILL CONTINUE TO MOVE NORTHEAST THROUGH THE REST OF
THE EVENING. ANOTHER LINE OF SHOWERS/STORMS WERE LOCATED ALONG THE
SURFACE BOUNDARY ROUGHLY FROM KMVX INTO SOUTHWEST MINNESOTA. SOME
OF THE STORMS HAVE BEEN STRONGER AND THEY SHOULD IMPACT KBRD
AROUND 01Z. MVFR CEILINGS/VSBYS WILL BE POSSIBLE WITH THE
SHOWERS/STORMS...THEN WE EXPECT PREVAILING CEILINGS TO LOWER
OVERNIGHT. THE RAP MOVES IN 1500-2500FT CEILINGS INTO THE
NORTHLAND OVERNIGHT. CEILINGS SHOULD RISE FOR MOST AREAS ON
SATURDAY...BUT WITH COLD AIR ALOFT AND THE UPPER TROUGH OVER THE
REGION...WE SHOULD SEE QUITE A BIT OF CU/STRATCU DEVELOP THROUGH
THE DAY AND SHOWERS. SHOWERS WILL BE MOST WIDESPREAD OVER THE
WESTERN AND FAR NORTHERN PORTIONS OF THE NORTHLAND. CEILINGS WILL
DIP INTO MVFR AT TIMES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 50 54 38 54 / 50 50 10 0
INL 52 53 35 52 / 60 60 30 10
BRD 48 54 36 57 / 60 50 10 0
HYR 53 61 36 58 / 30 10 10 0
ASX 56 61 39 57 / 30 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ144-145.
&&
$$
MESOSCALE...MELDE
SHORT TERM...GROCHOCINSKI
LONG TERM...DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
914 PM CDT FRI OCT 11 2013
.UPDATE...
MADE A COUPLE ADJUSTMENTS TO THE GRIDS TONIGHT. AN OUTFLOW BOUNDARY
OF SORTS TRAVELING NWD FROM LA WAS PRODUCING A COUPLE SCATTERED
SHOWERS IN S MS THIS EVENING SO A SLIGHT MENTION OF THESE WAS ADDED
TO THE GRIDS. THESE WON`T LAST MUCH LONGER HOWEVER. ALSO ADJUSTED
OVERNIGHT LOWS A BIT AFTER TAKING NOTE OF THE CURRENT TRENDS AND HOW
QUICKLY TEMPS DROPPED AFTER SUNSET. NOT GOING TO ISSUE A DENSE FOG
ADVISORY YET EITHER. THERE ARE INCREASED FEELINGS THAT THE MID-LEVEL
MOISTURE IS GOING TO DECREASE THE CHANCES FOR WIDESPREAD DENSE
FOG...ESPECIALLY SOUTH OF I-20. WILL KEEP AN EYE ON THIS THOUGH AS
DEWPOINT DEPRESSIONS ARE VERY LOW ALL AROUND. PATCHY FOG HOWEVER CAN
BE EXPECTED ACROSS THE CWA AFTER MIDNIGHT. /10/
&&
.AVIATION...
AREAS OF LOW STRATUS AND FOG SHOULD DEVELOP AND INCREASE AFTER 06Z
WITH LIFR RESTRICTIONS IN THE 09-15Z TIME FRAME...PARTICULARLY ALONG
AND SOUTH OF THE TVR-JAN-MEI CORRIDOR. INCREASING MID LEVEL
MOISTURE/CLOUDINESS SUGGEST THE FOG MAY NOT BE QUITE AS EXTENSIVE AS
FRIDAY MORNING. DAYTIME HEATING WILL MIX OUT STRATUS/FOG AND ALLOW
VFR CONDITIONS TO RETURN TO THE ENTIRE AREA AFTER 16Z AND CONTINUE
THROUGH SATURDAY EVENING. /EC/
&&
.PREV DISCUSSION... /ISSUED 402 PM CDT FRI OCT 11 2013/
SHORT TERM...
FRIDAY NIGHT THROUGH MONDAY MORNING...
TEMPERATURES TODAY HAVE WARMED UP QUICKLY AFTER THE FOG/STRATUS
CLEARED OUT OF THE REGION. GUIDANCE IS IN PRETTY GOOD AGREEMENT FOR
TEMPS OVERNIGHT AND WENT CLOSE TO MAV. MAIN FORECAST CONCERN WILL
BE THE POTENTIAL FOR DENSE FOG OVERNIGHT TONIGHT. THERE ARE CURRENTLY
DEWPOINTS IN THE UPPER 60S-LOW 70S S OF THE I-20 CORRIDOR. THIS HIGH
LOW LEVEL MOISTURE REGION WILL AID IN THE POTENTIAL FOR FOG
DEVELOPMENT TONIGHT AS FORECAST RUC DEWPOINT DEPRESSIONS ARE VERY LOW.
ALSO...LOW TEMPERATURES OVERNIGHT LOOK TO FALL BETWEEN 2-4 DEGREES
BELOW THE CROSSOVER TEMPERATURE. THIS WILL FAVOR THE POTENTIAL FOR
SOME DENSE FOG OVERNIGHT. DID NOT ISSUE A DENSE FOG ADVISORY AT THE
MOMENT BUT WILL KEEP AN EYE ON THE POTENTIAL. SOME MID-HIGH LEVEL
CLOUDS LOOK TO MOVE INTO THE REGION TONIGHT BUT DOES NOT LOOK TO
HINDER FOG POTENTIAL. FOG SHOULD LIFT EARLY SATURDAY MORNING AROUND
14-15Z. AN UPPER TROUGH OVER THE CENTRAL PLAINS WILL GRADUALLY PIVOT
NE...SLIDING THE S/WV RIDGE AXIS OVER THE REGION FURTHER EAST
OVERNIGHT TONIGHT INTO TOMORROW. THIS WILL AID IN A SURFACE FRONTAL
BOUNDARY APPROACHING THE AREA TOMORROW FROM THE W/NW. AS THE UPPER
TROUGH LIFTS N THROUGH THE NRN PLAINS...THE BOUNDARY WILL LOSE SOME
EASTWARD MOTION AND STALL ON THE WESTERN FRINGES OF THE REGION. SOME
SHOWERS COULD MOVE INTO THE NW/CENTRAL AREAS TOMORROW WITH SLIGHT
CHANCES FOR A THUNDERSTORM IN THE FAR NW DELTA DUE TO SOME ELEVATED
INSTABILITY IN THIS AREA. WENT CLOSE TO MAV HIGHS/POPS SATURDAY.
THERE COULD BE SOME PATCHY FOG POTENTIAL AGAIN SATURDAY NIGHT
AS LOW MAV INDICATES SOME LOW DEWPOINT DEPRESSIONS S OF THE I-20
CORRIDOR...ESPECIALLY IN THE SW. ALSO GUIDANCE INDICATES SOME
LINGERING SHOWERS BEFORE 12Z IN THE W/NW BUT SHOULD END AFTER 3-6Z.
H5 UPPER RIDGE OVER THE CENTRAL/SW GULF WILL GRADUALLY SLIDE E AND
THE AREA WILL WARM NICELY INTO THE MID/UPPER 80S SUNDAY. SOME HIGHER
PWATS IN THE SW WILL AID IN SOME POSSIBLE SHOWERS SUNDAY AFTERNOON
TO EVENING. WENT CLOSE TO MAV HIGHS/POPS SUNDAY. AS THE UPPER RIDGE
AXIS MOVES OVER THE REGION SUNDAY NIGHT INTO MONDAY MORNING...CLOUDS
WILL CLEAR SLIGHTLY IN THE E...SUPPORTING NEAR MAV LOWS MONDAY
MORNING. LINGERING RAIN CHANCES WILL END AROUND 3Z MONDAY IN THE
FAR SW. RELEVANT PORTION OF PREVIOUS LONG TERM DISCUSSION IS
ATTACHED. /DC/
LONG TERM...
MONDAY INTO LATE NEXT WEEK...
NOT TOO MUCH HAS CHANGED IN THE LONG TERM FROM YESTERDAY MORNING. THE
REGION WILL BE SITUATED UNDER AN UPPER RIDGE THROUGH THE WEEKEND. A
WEAKENING BOUNDARY WAS APPROACHING THE REGION EARLIER IN THE WEEKEND
BUT LOOKS TO STALL TO OUR WEST. MOST OF THE ARKLAMISS WILL REMAIN ON
THE DRIER AND WARMER SIDE GIVEN THE INFLUENCE OF THE UPPER RIDGE.
TEMPERATURES WILL BE IN THE MID TO PERHAPS EVEN UPPER 80S THROUGH
MID-WEEK. CHANGES WILL BE ON THE WAY AS ANOTHER LOW PRESSURE SYSTEM
DEVELOPS ACROSS THE WEST AND BRINGS A FRONT TOWARD THE REGION. MODELS
REMAIN IN FAIRLY GOOD AGREEMENT ABOUT BRINGING THIS FRONT THROUGH
MID-WEEK...GENERALLY AROUND THE WEDNESDAY TO THURSDAY TIME PERIOD.
THE 12Z ECMWF WAS MUCH SLOWER IN BRINGING THE FRONT AND ASSOCIATED
RAINS THROUGH THE REGION...STALLING IT AGAIN TO THE WEST UNTIL BETTER
SUPPORT BROUGHT IT THROUGH BY THE END OF NEXT WEEKEND. THE 00Z ECMWF
RETURNS MORE IN LINE WITH LAST NIGHTS MODEL RUN AND THE MOST RECENT
00Z GFS AND GFS ENSEMBLES WITH BRINGING THE FRONT THROUGH ON WED-
THURS AND CLEARING OUT THE RAIN SHORTLY THEREAFTER. AT THIS
TIME...STILL LOOKS LIKE JUST RAIN AS INSTABILITY IS NOT GREAT. MODELS
CLEAR OUT THE REGION FOR THE WEEKEND WHILE COOLER TEMPERATURES AND
DRIER AIR FILTER IN. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 63 85 64 88 / 4 14 14 20
MERIDIAN 59 86 61 88 / 3 5 4 10
VICKSBURG 62 85 63 88 / 7 25 18 28
HATTIESBURG 63 87 63 89 / 6 6 6 20
NATCHEZ 65 84 66 85 / 5 22 15 36
GREENVILLE 62 85 64 85 / 11 35 24 14
GREENWOOD 61 85 63 87 / 7 26 16 9
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
946 PM CDT Fri Oct 11 2013
.UPDATE:
Issued at 929 PM CDT Fri Oct 11 2013
Scattered showers and thunderstorms currently extending from
northwest Missouri through southeast Kansas is in response to
upstream upper air pertubation over eastern Colorado southwest
Kansas moving east-northweastward into northern and central
Kansas. Cold frontal boundary extending from western Iowa through
northeast Kansas then south-central Kansas continues too move east
and southeastward. We delayed the arrival of showers and
thunderstorms over most areas in the LSX CWA. Believe shower and
thunderstorm activitly will be moving into Qunicy - Columbia area
after 0700 UTC and into St. Louis area after 10 or 11 UTC. Would
not be surprise if a new band of convection forms after midhight ahead
of the current bands observed on EAX and SGF radars. RAP and local
LSX WRF models supporting this tread. Instability not too
impressive at this time over area. Well defined subsidence
inversion at 780 mb noted at SGF sounding this evening. This might
challenge convection a little. However colder air aloft over
western Kansas may increase the instability early Saturday
morning. Adjusted temps a little over CWA.
Przybylinski
&&
.SHORT TERM: (Through Late Tonight)
Issued at 318 PM CDT Fri Oct 11 2013
Although upstream front/dry line remain tranquil at 20z, believe
that modest instability and convergence along the front should
initiate scattered convection over the next few hours. The coverage
of this activity should then increase later tonight as upstream
shortwave currently near the 4 corners works into the region. It
may take a while for the upstream convection to work into the CWA,
but amount of moisture, instability, and lift all suggest scattered
convection will threaten much of the CWA late tonight and during the
predawn hours. For now have placed the highest PoPs at 50% west of
a KFAM-KTAZ line, with PoPs tapering off southeast of this line to
low chance in KSLO area by daybreak. For now have stayed with
overnight lows in the 50s with the thinking that there should be a
bit of cooling due to precip; however if convection does remain
isolated these lows will likely be too cool by a cat or so.
Truett
.LONG TERM: (Saturday through Next Friday)
Issued at 318 PM CDT Fri Oct 11 2013
Overall forecast trends appear on track for tomorrow with scattered
showers and thunderstorms expected to persist from tonight into
Saturday. A stacked low pressure system over the northern Plains
will lift into Canada by tomorrow morning while at least one
secondary vort max rotates around its back side, providing another
source of lift for MO/IL. The occluding system will also continue to
draw a narrow ribbon of moisture through the area ahead of the cold
front (PW values will be near +2 SD). In addition, models are
forecasting a coupled jet structure at H3 which places the LSX CWA
beneath the favored region for enhanced lift, especially between
12-18z. The combination of these factors should be sufficient for
isolated to scattered precipitation, but this does not look like a
widespread rainfall event because of the spatially limited moisture
and overall weak forcing.
Precipitation should end fairly quickly after the cold front moves
through the region due to increasing subsidence with a 1025 hPa high
pressure center that will be sliding into the northern Plains and
western Great Lakes on Saturday night and Sunday. This area of high
pressure will push the cold front to near the MO/AR border before
cyclogenesis over the central Plains occurs and lifts the stalled
boundary back northward as a warm front on Tuesday. There are still
some model differences regarding the upper level disturbance which
will be responsible for the surface low, but recent runs of the
ECMWF/GFS/GEM all agree at that least a portion of that energy will
lift through the central CONUS on Monday night and Tuesday. The
moisture and dynamics are expected to be much better with the
Mon/Tue system. Depending on how the upper level disturbance splits
apart, the other half could move across the area during the middle
or end of the week and provide additional precipitation chances.
Kanofsky
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 542 PM CDT Fri Oct 11 2013
Cold front extending from a sfc low over sern ND s-sw into cntrl
KS will move sewd through UIN and COU late tgt, and through the St
Louis metro area Saturday mrng. Scattered showers and a few
thunderstorms are expected along and just ahead of this front. A
band of VFR, low level clouds ahead of the front will move into
COU and UIN early this evng, and into the St Louis metro area late
this evng. Showers and a few storms should move through UIN and
COU around 06z Saturday, and through the St Louis metro area around
12z Saturday. The s-sely sfc wind should weaken this evng and lose
the gusts, then veer around to a nwly direction after fropa in
UIN and COU by early Saturday mrng and in the St Louis metro area
by late mrng. The low level clouds will clear out in the mrng in
UIN and COU, and in the aftn in the St Louis metro area as a ridge
of high pressure builds into the area behind the cold front.
Specifics for KSTL: Clouds at 4000-6000 ft will advect into STL
by late this evng with scattered showers moving into the STL area
by 12z Saturday. The showers will move out by late mrng with the
clouds clearing out in the aftn. Sely sfc wind will weaken tgt and
veer around to a swly direction Saturday mrng, and a nwly direction
Saturday aftn.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
806 PM CDT FRI OCT 11 2013
.UPDATE...
Issued at 803 PM CDT FRI OCT 11 2013
Forecaster`s intuition was correct and thunderstorms have quickly
erupted along the confluence zone over NE KS/NW MO. Recent IR
satellite imagery clearly depicts the moisture discontinuities with
the dryline and the trailing cold front, with the front poised to
overtake the dryline during the next several hours.
The net increase in large scale ascent provided by the boundary
push, aided by an increasing low level jet, was already being
evidenced by increasing cumulus over eastern KS into central OK as
well as mid cloud development back toward Medicine Lodge/Hutchison.
Thus, I would expect a gradual increase in thunderstorm coverage
over the next several hours.
As of 01Z, the narrow axis of thunderstorms has been generally
stationary/training, and oriented parallel to the deep layer shear.
However, this is likely to change very shortly as stronger forcing
arrives from the west, giving the ongoing convection an eastward
push, while also allowing storms that may develop further south down
the boundary to be a bit more discrete. Storm scale rotation remains
possible further south where shear will be at a more obtuse angle to
the frontal zone, perhaps leading to a few severe storms through
03-04Z.
Bookbinder
.MESOSCALE DISCUSSION...
Issued at 453 PM CDT FRI OCT 11 2013
Latest surface analysis shows a broad confluence zone stretching
through eastern Kansas, situated along the western edge of a low
level moist axis characterized by dewpoints in the lower 60s.
Visible satellite imagery shows that clouds have scattered between
the approaching surface dryline and widespread overcast across
western MO, with a congealing line of cumulus present from FNB to
EMP where temperatures have quickly climbed to near 80 degrees. This
has yielded modest SBCAPE between 500-1000 J/kg, thanks to
seasonably rich moisture in the sfc-800mb layer and dry air
advancing aloft ahead of the upper trough. Potential cloud bearing
shear values are quite strong ahead of the upper trough, estimated
based on recent aircraft soundings between 45-50 knots, with vectors
largely orthogonal to the dryline and trailing cold front
orientations.
The big question mark over the next several hours will be whether or
not sufficient low level convergence can lift out the remaining
inhibition (roughly 50 J/kg) still present per latest RUC analysis.
Although several convective allowing models and the NAM-WRF do
generate deep convection, their preferred location seems to be well
east of where recent trends suggest its most possible. Several
scenarios remain plausible, including a null event. However, it
seems to reason that sufficient synoptic forcing and/or the evening
low level jet should force at least isolated convection sometime in
the next 1-3 hours, possibly as far west as eastern Kansas.
/If/ storms develop...0-3km CAPE between 100-200 J/kg, coupled with
favorable deep layer shear could support discrete storms capable of
producing bouts of at least marginal severe weather through mid
evening. Obviously concerns surrounding numerous ongoing evening
activities as well, so will monitor closely for signs of
development.
Bookbinder
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 355 PM CDT FRI OCT 11 2013
Forecast for the next couple of days is focused on precipitation
chances for tonight. Water vapor imagery shows us a compact low
lifting northeast through Dakota`s with a cold front extending south
through eastern Nebraska and central Kansas. The band of showers
that transited the forecast area earlier today has petered out as
the spoke of isentropic lift that was helping fuel this activity on
the 300K to 305K surfaces has shifted off to the northeast. Thick
cloud cover across western Missouri, with more scattered cover in
eastern Kansas, is a result of the continued broad isentropic assent
occurring ahead of the cold front in Kansas. As the front pushes
slowly east tonight lift ahead of the front will intersect the
deeper moisture across Missouri, likely resulting in showers and
embedded thunderstorms tonight. Current short range model outputs
indicate that much of this activity will likely develop in place
across western Missouri, and recent visible satellite imagery backs
that assertion up as the cloud cover is looking decidedly flat at
this time. As a result, still expect storms to develop late this
afternoon and-or early this evening across western Missouri
--possibly just east of KC--, with the potential for a good wetting
rain increasing as you move towards central Missouri. Much of the
activity under the "Friday Night Lights" should be minimally
impacted as showers and thunderstorms likely wont get going till the
mid to late evening hours --after 7 PM--. That being said, when
storms do develop lightning will be of concern to anyone still
outside.
By Saturday morning the front, and associated showers, will have
left our section of Missouri behind. Near normal temperatures will
sweep in to dominate the rest of the weekend with highs in the upper
60s to low 70s for both Saturday and Sunday. Next chance at storms
will arrive Monday as another storm system moves through the Plains
States.
.LONG TERM...(Monday through Friday)
Issued at 355 PM CDT FRI OCT 11 2013
Another upper trough is slated to dig/deepen over the Great Basin
Sunday night with southwesterly flow aloft downstream. The general
model trend through Tuesday allows for a broadening and positive
tilting of this upper trough with several pieces of energy ejecting
through the Central/Northern Plains and Upper MS Valley while
retaining a secondary shortwave in the base of the trough. The
initial shortwave ejecting out of the main upper trough is expected
to track further south than the one currently moving through NE/SD.
This should allow for a better quality of low level moisture to work
into the MO River Valley for convective development at the start of
the work week.
Sunday night: Dome of Pacific high pressure will retreat eastward
overnight while warm air advection begins to ramp-up over the
Central Plains in response to pressure falls ahead of the first
shortwave ejecting from the Great Basin upper trough. Believe there
will be enough dry air to overcome due to easterly boundary layer
flow to hold precipitation at bay for most of the night except for
the far western CWA where slight chance PoPs inserted after midnight.
Monday-Tuesday: Models are in very good agreement with strong/deep
isentropic ascent on the 300K through 315K layers although the 12z
NAM may be a bit too fast in spreading precipitation east. However,
don`t want to underestimate the degree of warm air advection. High
confidence on going with high PoPs for Monday/Monday night. Have
raised Monday max temperatures over the eastern CWA due to a delay
in precipitation arriving and partial sunshine. A cold front moving
through KS/MO Monday night will likely enhance convergence and
likely another round of convection Monday night.
Mid level dry slot wrapping under the surface low passing north of
the CWA will strip away deeper moisture and limit qpf on Tuesday.
Scattered residual showers are expected to end from west to east
during the morning. Cold air advection and left over cloud cover
will result in below average temperatures.
Wednesday-Friday: Confidence decreases markedly during this period
owing to widening model spread with time. Wrap around cloud
cover/sprinkles associated with the departing cyclone could spread
back into the CWA on Wednesday as suggested by ECMWF/GFS solutions.
Despite the wide model spread there is an over-riding theme during
this period and it revolves around below average temperatures. Will
leave precipitation out for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 647 PM CDT FRI OCT 11 2013
Skies have cleared across the terminals in advance of a dryline
moving into eastern Kansas. Satellite imagery suggest that showers
and thunderstorms may develop in the next 1-2 hours, with a chance
that this activity (if it develops) would impact the terminals from
roughly 0130-0400Z. The dryline passage should induce a wind shift
from the south to the west-southwest, with a subsequent shift to the
northwest upon cold front passage toward 06Z.
VFR conditions will continue through the period outside of any
thunderstorms this evening.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Bookbinder
MESOSCALE DISCUSSION...Bookbinder
SHORT TERM...Cutter
LONG TERM...MJ
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
647 PM CDT FRI OCT 11 2013
.MESOSCALE DISCUSSION...
Issued at 453 PM CDT FRI OCT 11 2013
Latest surface analysis shows a broad confluence zone stretching
through eastern Kansas, situated along the western edge of a low
level moist axis characterized by dewpoints in the lower 60s.
Visible satellite imagery shows that clouds have scattered between
the approaching surface dryline and widespread overcast across
western MO, with a congealing line of cumulus present from FNB to
EMP where temperatures have quickly climbed to near 80 degrees. This
has yielded modest SBCAPE between 500-1000 J/kg, thanks to
seasonably rich moisture in the sfc-800mb layer and dry air
advancing aloft ahead of the upper trough. Potential cloud bearing
shear values are quite strong ahead of the upper trough, estimated
based on recent aircraft soundings between 45-50 knots, with vectors
largely orthogonal to the dryline and trailing cold front
orientations.
The big question mark over the next several hours will be whether or
not sufficient low level convergence can lift out the remaining
inhibition (roughly 50 J/kg) still present per latest RUC analysis.
Although several convective allowing models and the NAM-WRF do
generate deep convection, their preferred location seems to be well
east of where recent trends suggest its most possible. Several
scenarios remain plausible, including a null event. However, it
seems to reason that sufficient synoptic forcing and/or the evening
low level jet should force at least isolated convection sometime in
the next 1-3 hours, possibly as far west as eastern Kansas.
/If/ storms develop...0-3km CAPE between 100-200 J/kg, coupled with
favorable deep layer shear could support discrete storms capable of
producing bouts of at least marginal severe weather through mid
evening. Obviously concerns surrounding numerous ongoing evening
activities as well, so will monitor closely for signs of
development.
Bookbinder
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 355 PM CDT FRI OCT 11 2013
Forecast for the next couple of days is focused on precipitation
chances for tonight. Water vapor imagery shows us a compact low
lifting northeast through Dakota`s with a cold front extending south
through eastern Nebraska and central Kansas. The band of showers
that transited the forecast area earlier today has petered out as
the spoke of isentropic lift that was helping fuel this activity on
the 300K to 305K surfaces has shifted off to the northeast. Thick
cloud cover across western Missouri, with more scattered cover in
eastern Kansas, is a result of the continued broad isentropic assent
occurring ahead of the cold front in Kansas. As the front pushes
slowly east tonight lift ahead of the front will intersect the
deeper moisture across Missouri, likely resulting in showers and
embedded thunderstorms tonight. Current short range model outputs
indicate that much of this activity will likely develop in place
across western Missouri, and recent visible satellite imagery backs
that assertion up as the cloud cover is looking decidedly flat at
this time. As a result, still expect storms to develop late this
afternoon and-or early this evening across western Missouri
--possibly just east of KC--, with the potential for a good wetting
rain increasing as you move towards central Missouri. Much of the
activity under the "Friday Night Lights" should be minimally
impacted as showers and thunderstorms likely wont get going till the
mid to late evening hours --after 7 PM--. That being said, when
storms do develop lightning will be of concern to anyone still
outside.
By Saturday morning the front, and associated showers, will have
left our section of Missouri behind. Near normal temperatures will
sweep in to dominate the rest of the weekend with highs in the upper
60s to low 70s for both Saturday and Sunday. Next chance at storms
will arrive Monday as another storm system moves through the Plains
States.
.LONG TERM...(Monday through Friday)
Issued at 355 PM CDT FRI OCT 11 2013
Another upper trough is slated to dig/deepen over the Great Basin
Sunday night with southwesterly flow aloft downstream. The general
model trend through Tuesday allows for a broadening and positive
tilting of this upper trough with several pieces of energy ejecting
through the Central/Northern Plains and Upper MS Valley while
retaining a secondary shortwave in the base of the trough. The
initial shortwave ejecting out of the main upper trough is expected
to track further south than the one currently moving through NE/SD.
This should allow for a better quality of low level moisture to work
into the MO River Valley for convective development at the start of
the work week.
Sunday night: Dome of Pacific high pressure will retreat eastward
overnight while warm air advection begins to ramp-up over the
Central Plains in response to pressure falls ahead of the first
shortwave ejecting from the Great Basin upper trough. Believe there
will be enough dry air to overcome due to easterly boundary layer
flow to hold precipitation at bay for most of the night except for
the far western CWA where slight chance PoPs inserted after midnight.
Monday-Tuesday: Models are in very good agreement with strong/deep
isentropic ascent on the 300K through 315K layers although the 12z
NAM may be a bit too fast in spreading precipitation east. However,
don`t want to underestimate the degree of warm air advection. High
confidence on going with high PoPs for Monday/Monday night. Have
raised Monday max temperatures over the eastern CWA due to a delay
in precipitation arriving and partial sunshine. A cold front moving
through KS/MO Monday night will likely enhance convergence and
likely another round of convection Monday night.
Mid level dry slot wrapping under the surface low passing north of
the CWA will strip away deeper moisture and limit qpf on Tuesday.
Scattered residual showers are expected to end from west to east
during the morning. Cold air advection and left over cloud cover
will result in below average temperatures.
Wednesday-Friday: Confidence decreases markedly during this period
owing to widening model spread with time. Wrap around cloud
cover/sprinkles associated with the departing cyclone could spread
back into the CWA on Wednesday as suggested by ECMWF/GFS solutions.
Despite the wide model spread there is an over-riding theme during
this period and it revolves around below average temperatures. Will
leave precipitation out for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 647 PM CDT FRI OCT 11 2013
Skies have cleared across the terminals in advance of a dryline
moving into eastern Kansas. Satellite imagery suggest that showers
and thunderstorms may develop in the next 1-2 hours, with a chance
that this activity (if it develops) would impact the terminals from
roughly 0130-0400Z. The dryline passage should induce a wind shift
from the south to the west-southwest, with a subsequent shift to the
northwest upon cold front passage toward 06Z.
VFR conditions will continue through the period outside of any
thunderstorms this evening.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
MESOSCALE DISCUSSION...Bookbinder
SHORT TERM...Cutter
LONG TERM...MJ
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
154 AM EDT THU OCT 10 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST UNITED STATES TONIGHT WILL GIVE
WAY TO A LOW PRESSURE SYSTEM MOVING UP ALONG THE EAST COAST
THURSDAY INTO FRIDAY, BRINGING A CHANCE OF SHOWERS TO THE AREA.
THE BEST CHANCE FOR SHOWERS WILL BE ACROSS NORTHEAST PENNSYLVANIA
AND THE CATSKILLS. EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL FOR
EARLY TO MID OCTOBER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
1020 PM UPDATE...
FORECAST IN GOOD SHAPE. LATEST HRRR STILL SUPPORTS A DRY
OVERNIGHT...WITH A FEW SHOWERS POSSIBLE TOWARD 15Z FAR SOUTH. THIS
MATCHES UP WELL WITH THE CURRENT FORECAST SO LITTLE TO CHANGE.
ALSO LEFT IN THE MENTION OF PATCHY FOG IN THE VALLEYS. WHILE THE
CIRRUS SHIELD IS ALREADY OVERHEAD...IT IS NOT VERY THICK WITH THE
STARS STILL VISIBLE. IT TAKES A LOT TO NOT HAVE FOG IN OUR RIVER
VALLEYS SO FOR NOW PATCHY FOG LOOKS REASONABLE. THE PREVIOUS AFD IS
BELOW...
FOR THE REST OF THE AFTERNOON...WE EXPECT TO SEE CONTINUED
HIGH LEVEL MOISTURE ADVECTION FROM THE MIDDLE ATLANTIC LOW SUPPORT
MORE CIRRUS INTO NY AND PA WHICH WILL THIN OUT AS IT WORKS INTO A
REGION OF UPPER LEVEL SUBSDC. THIS SUBSDC WAS SUPPORTG A LL
ANTICYCLONE OVER THE NORTHEAST U.S. WITH SUBSBC...850-925 MB TEMPS
CONT TO WARM AND WILL BE IN THE LOW TO MID 50S (F) THIS PM. THE
SFC LAYER REMAINS FAIRLY DRY WITH DEWPOINTS ONLY THE UPPER 30S AND
40S. THIS COLLABORATES THE MODEL SOUNDING DATA WHICH SUGGEST NO
CUMULUS FORMS WITH THE DAY/S HEATING. HENCE ALL WE WILL HAVE IN
THE SKY GRIDS IS RELATED TO THINNING CI. CIRRUS WILL BE THICKEST
IN NE PA IN CLOSER PROXIMITY TO THE MID ATLANTIC SYSTEM. OTHERWISE
A MILD FALL DAY WITH FILTERED SUNSHINE.
FOR TONIGHT...WEAK MID ATLANTIC CYCLONE CONTINUES TO SLOWLY WORK
NORTHWARD AS PER ALL SYNOPTIC AND MESOSCALE MODEL GUIDC. THIS
FEATURE SUPPORTS A FAIRLY STRG LL ERLY JET DUE TO THE STRG HIGH
PRESSURE SYSTEM TO THE NE WHICH IS ENHANCING THE PRES GRAD. HENCE
WE HAVE A WEAK SFC LOW OFF THE MID ATLANTIC COAST WITH A PRETTY
DECENT PRESSURE GRADIENT TO THE NORTH. THIS WILL LEAD TO DECENT
MOISTURE ADVECTIONS INTO NE PA BEGINNING LATE TONIGHT...BUT GIVEN
THAT THE LOWER AMS BEGINS VERY DRY WE DON/T SEE MUCH IF ANY PRECIP
REACHING NE PA B4 12Z THU. SO MID TO HI CLDS WILL STREAM
NORTHWARD INTO NE PA AND THIN OUT OVERNGT AS THEY WORK INTO C NY.
THERE LIKELY WILL BE VALLEY FOG FORMING IN C NY WHERE MOSTLY CLR
SKIES WILL PREDOMINATE AND LIGHT WINDS...BUT IT WON/T BE AS
EXTENSIVE AS THIS MORNING/S FOG.
BY LATER THU...850 MB JET AS PER GFS...EURO AND CMC MOVES TO THE
NORTH OF THIS ADVANCING CYCLONE AND REACHES ACRS ALL OF NE
PA/CATSKILLS AND INTO SC NY. THE NAM CONTS TO BE THE ODD MODEL OUT
KEEPING THE BEST MOISTURE ADVTNS AND ALL QPF TO THE SOUTH B4 00Z
FRI. THINK PRECIP WILL CREEP NORTHWARD AND DRY OUT THU PM BUT
SOME LIGHT PRECIP WILL POTENTIALLY REACH INTO NE PA BY LATE THU.
THERE IS UNCERTAINTY AS TO HOW FAR N AND W THE PRECIP MAKES IT
INTO SC NY THU PM GIVEN THE DRY LL/S SO BASICALLY HAVE DROPPED
POPS IN C NY UNTIL THU NGT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
MID-ATLANTIC CYCLONE SLOWLY WORKS NORTHWARD REACHING OFF THE VA/NC
COAST BY 12Z FRI ON THE CMC...EURO AND GFS. THE NAM CONTS TO BE
THE OUTLIER WITH THE SFC LOW AND ASSCTD UPPER LOW MUCH FARTHER S
ONLY REACHING OFF THE SC COAST AT THE SAME TIME. SINCE THE
GFS/EURO AND CMC HAVE BEEN CONSISTENT ALL SHOW SOME LIGHT PRECIP
REACHING INTO NE PA AND THE CATSKILLS THU NGT...ESP LATER AT NGT.
AS SUCH HAVE GRADUALLY RAMPED POPS UP THU NGT FRM CHC TO LIKELY IN
THE POCONOS BTWN 00Z AND 12Z FRI AND FROM BELOW 15 PCT TO CHC
MOST OF REST OF CWA AND REACHING UP TO SLGHT CHC IN OUR FAR NW
COUNTIES MAINLY ACROSS THE FINGER LAKES TO UPPER MOHAWK THU NGT.
FRIDAY THE CYCLONE THEN BEGINS TO PUSH BACK TO THE SOUTH SLOWLY.
THIS IS IN RESPONSE TO AN UPPER LEVEL WAVE WHICH DROPS SOUTHWARD ACRS
SERN CANADA AND RE-ENFORCES LL HIGH PRESSURE ACRS THE NE U.S AND
SERN CANADA IT IS WAKE ON FROM FRI INTO SAT. HENCE POPS PEAK FRI
PM FROM SLGHT CHC NW ZONES TO CHC/LIKELY IN THE SERN ZONES. THEN I
HAVE POPS TRENDING BACK DOWN FRI NGT THRU SAT AS THE UPPER LEVEL
LOW IS PUSHED SOUTHWARD. FOR QPF POTENTIALLY UP TO 1/2 TO 1 INCH
WHICH SHUD NOT CAUSE ANY HYDRO ISSUES MAINLY POCONOS-CATSKILLS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STILL SOME MODEL DISAGREEMENT TO START OUT THE EXTENDED TIME FRAME
WITH RESPECT TO POTENTIAL IMPACTS ACROSS OUR REGION FROM CLOSED LOW
PRESSURE CENTER PERSISTING OFF THE MID-ATLANTIC COAST. GFS AND
CANADIAN-CMC CONTINUE TO SHOW THE FEATURE GRADUALLY DEFLECTING TO
THE SOUTH AS WEAK SHORTWAVE RIDGING BUILDS OVER THE NORTHEAST THIS
WEEKEND. THE ECMWF ON THE OTHER HAND SHOWS A FURTHER NORTHWARD
POSITION WITH POSSIBLE SHWR ACTIVITY PERSISTING ACROSS OUR REGION
THROUGH EARLY NEXT WEEK BEFORE A WEAK COLD FRONT MOVES THROUGH
THE AREA BY LATE MONDAY/EARLY TUESDAY TIMEFRAME. FOR NOW...WILL
ADVERTISE SLGT CHC POPS ACROSS THE FAR SOUTH AND SOUTHEAST AT THE
START OF THE PERIOD BEFORE INCREASING POPS REGION WIDE BY
MONDAY IN ANTICIPATION OF AFOREMENTIONED FRONT. WX BECOMES A BIT
MORE INTERESTING BY TUESDAY/WEDNESDAY AS A STRONG STORM SYSTEM
SHIFTING EAST FROM THE CENTRAL/NORTHERN PLANS REGION LIFTS A WARM
FRONT NORTH THROUGH THE AREA. FROM THIS VANTAGE POINT...STORM
SYSTEM APPEARS FAIRLY WELL SUPPORTED WITH STRONG DYNAMICS ALOFT
AND HAVE INCREASED POPS INTO THE CHC CATEGORY BY MIDWEEK BASED ON
FAVORABLE AGREEMENT BETWEEN THE ECMWF AND GFS. THAT SAID...SOME
DISAGREEMENTS WITH 12Z MODEL SUITE AND FROPA TIMING...HOWEVER
INDICATIONS SUGGEST A REGION WIDE RAIN EVENT WILL BE POSSIBLE BY
MIDWEEK AS STORM SYSTEM MOVES EAST WITH TIME.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
140 AM EDT UPDATE...
VFR CONDITIONS WITH LIGHT WINDS ARE EXPECTED FOR ALL TAFS THROUGH
THE NEXT 24 HOURS EXCEPT FOR KELM. FOG HAS DEVELOPED THIS MORNING
AT KELM DESPITE WIDESPREAD COVERAGE OF HIGH CLOUDS ACROSS NEW
YORK. AT THE MOMENT DECIDED TO KEEP A TEMPO IN FOR VISBYS WITH
BELOW ALTERNATE MINIMUMS THROUGH 10Z. THE FORECAST CHALLENGE OF
THE NIGHT IS HOW DENSE WILL THE FOG GET AT KELM. CONFIDENCE IS NOT
HIGH THAT IT WILL BECOME AS DENSE AS LAST NIGHT SO LEFT 1SM BR FOR
THE TIME BEING.
OUTLOOK...
THU NGT-MON...VFR WITH THE EXCEPTION OF POTENTIAL VALLEY FOG
ACROSS THE TWIN TIERS EACH MORNING OVER THE WEEKEND
/MAINLY IMPACTING KELM/.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/HEDEN
SHORT TERM...DJN
LONG TERM...CMG
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1244 PM CDT THU OCT 10 2013
.UPDATE...
ISSUED AT 1244 PM CDT THU OCT 10 2013
MINOR CHANGES REQUIRED WITH EARLY AFTERNOON UPDATE. MUCH OF
SOUTHERN TWO THIRDS OF CWA HAVE CLEARED OUT WITH CIRRUS MOVING IN
FROM UPSTREAM...SO HAVE DECREASED SKY THROUGH 00Z FRIDAY. MODELS
IN DECENT AGREEMENT WITH PRECIP ASSOCIATED WITH TOMORROWS SYSTEM
ENDING AFT 03Z SUN...AND HAVE REMOVED POPS FOR MOST OF SAT NIGHT.
NEXT SYSTEM LIFTS INTO SOUTHEASTERN ND ON LATE SUN AFTN AND HAVE
ADDED A CHANCE FOR RAIN FROM 21Z SUN TO 00Z MON. NO OTHER CHANGES
FOR TONIGHT AND SATURDAY AT THIS TIME AS AWAITING NEWEST SREF AND
ECMWF. BIG CHALLENGE WILL BE TIMING PRECIP INTO THE WESTERN
CWA...AND HAVE ADDED A CHANCE IN FOR THE UPPER SHEYENNE VALLEY
(FROM SLIGHT CHANCE) EARLY IN THE EVENING.
UPDATE ISSUED AT 935 AM CDT THU OCT 10 2013
MAIN FORECAST CONCERN THIS MORNING WILL BE WHICH 12Z MODEL
INITIALIZES BEST FOR PRECIP STARTING LATE TONIGHT INTO FRI
MORNING. 12Z NAM APPEARS TO BE TOO DRY WITH ACTIVITY OVER EASTERN
SD WHILE THE LATEST RUC IS TOO AGGRESSIVE IN BRINGING THAT SHOWERY
ACTIVITY INTO OUR CWA (TOO EARLY IF AT ALL). SO NO PLANS (FROM
LATEST NAM RUN) FOR MAIN SYSTEM WHICH WILL BRING RAIN TO THE AREA
TOMORROW. ONLY FCST CHANGE FOR NOW WILL BE TO FURTHER INCREASE SKY
BASED ON CURRENT SAT TRENDS...MAINLY ACROSS THE NORTHERN HALF OF
CWA. WILL LOOK AT TEMPS CLOSER TO 10 AM BUT NO MAJOR PLANS
EXPECTED FOR DAYTIME HIGHS.
UPDATE ISSUED AT 641 AM CDT THU OCT 10 2013
MADE A FEW TWEAKS TO CLOUDS AS HIGH AND MID LEVEL CLOUDS CONTINUE
TO SPREAD OVER THE AREA ALTHOUGH THERE APPEAR TO BE SOME BREAKS.
TEMPS HAVE STAYED IN THE 40S TO LOW 50S AND THINK EVEN WITH HIGH
CLOUDS WE SHOULD STILL GET INTO THE 60S AND 70S THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT THU OCT 10 2013
TEMPERATURES TODAY AND PRECIP CHANCES TONIGHT AND TOMORROW WILL BE
THE MAIN ISSUES FOR THE SHORT TERM.
WV LOOP SHOWS THE MAIN UPPER LOW DIGGING FROM SOUTHERN CA INTO
AZ...AND THE SYSTEM WILL SWING NORTHEASTWARD INTO THE CENTRAL
ROCKIES LATER TODAY. A WEAK LEAD SHORTWAVE HAS BEEN PRODUCING SOME
SHOWERS OVER NORTHWESTERN ND...BUT THE UPPER FLOW HAS IT TRACKING
INTO CANADA AND STAYING WEST OF US. WILL CONTINUE TO KEEP THE
FORECAST DRY THROUGH 00Z. THERE WILL BE PLENTY OF MID AND HIGH
CLOUDS IN THE SOUTHWESTERLY FLOW OVER THE NORTHERN PLAINS.
INSOLATION WILL BE REDUCED A BIT BUT THERE WILL BE PLENTY OF WARM
AIR ADVECTION AS SOUTHEASTERLY WINDS PICK UP AHEAD OF THE SFC LOW
TODAY. KEPT HIGHS IN THE UPPER 60S TO MID 70S.
THE UPPER LOW WILL BE CLOSING OFF AND MOVING INTO THE SD/NEB
REGION TONIGHT. Q VECTOR CONVERGENCE SHOWS THE BEST SUPPORT WITH
THE UPPER LOW WILL REMAIN MOSTLY TO OUR SOUTHWEST OVERNIGHT...BUT
SOME PRECIP COULD BEGIN TO MOVE INTO THE DEVILS LAKE AREA LATER
ON. MADE ONLY MINOR TWEAKS TO THE 30-40 POPS THAT WE HAD GOING FOR
OUR WESTERN COUNTIES.
THE UPPER LOW WILL BE LIFTING INTO EASTERN ND DURING THE DAY ON
FRIDAY...WITH A FAIRLY STACKED SFC LOW TAKING A SIMILAR TRACK.
THE MODELS STILL HAVE SOME MINOR DIFFERENCES IN EXACTLY WHERE THEY
PUT THE SFC LOW BUT ARE IN BETTER AGREEMENT THAN LAST NIGHT. WITH
STRONG UPPER SUPPORT AS THE SYSTEM MOVES INTO THE AREA CONTINUED
TO KEEP PRETTY HIGH POPS FOR FRIDAY AS SHOWERS AND THUNDERSTORMS
MOVE ACROSS THE AREA IN THE WARM SIDE OF THE SFC LOW. WITH THE
VERY STRONG UPPER SYSTEM...THERE IS THE POSSIBILITY OF SOME LOW
TOPPED SUPERCELLS IF WE GET THE CAPE THAT THE NAM IS
SUGGESTING...AROUND 500 J/KG. MUCH WILL DEPEND ON HOW MUCH CLOUD
COVER WE REALLY END UP WITH...AND SOME OF THE MODELS HAVE NOT MUCH
SFC INSTABILITY AT ALL. WILL INCLUDE A MENTION IN THE HWO FOR
POSSIBILITY OF SEVERE BUT WILL NOT INCLUDE IN GRIDS FOR NOW.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU OCT 10 2013
FRIDAY NIGHT...THE UPPER LOW WILL LIFT OFF INTO CANADA...AND THE
COLD FRONT WILL MOVE THROUGH. WITH THE TIGHT PRESSURE GRADIENT WINDS
WILL BECOME QUITE STRONG AND BE ASSISTED BY COLD AIR ADVECTION ON
THE BACKSIDE OF THE SFC LOW. SO WILL HAVE TO WATCH OUT FOR
ADVISORY CRITERIA EVEN AT NIGHT. SHOWERS WILL CONTINUE MAINLY OVER
THE NORTHERN CWA AS PRECIP WRAPS AROUND THE BACKSIDE OF THE LOW AS
IT LIFTS OUT. THE ECMWF AND GEM KEEP PRECIP A BIT FURTHER WEST
INTO SATURDAY WHILE THE DOMESTIC MODELS JUST KEEP SOME ACTIVITY
OVER THE NORTHEASTERN COUNTIES. WITH CONVECTIVE TEMPS PRETTY LOW
THINK THAT SHOWER ACTIVITY WILL CONTINUE OVER AT LEAST PART OF THE
CWA SO KEPT 20-30 POPS GOING FOR A WHILE EVEN AS SFC HIGH PRESSURE
BUILDS INTO THE AREA. THE SFC HIGH AND COOL AIR WILL HELP SATURDAY
NIGHT DROP BACK INTO THE 30S.
SUNDAY TO WEDNESDAY NIGHT...MODELS IN FAIR AGREEMENT WITH THE
BEGINNING OF NEXT WEEK BRINGING IN THE NEXT STORM SYSTEM ON MONDAY
AND INTO TUESDAY. POPS INCREASED TO LIKELY ACROSS THE S RRV FOR
TUESDAY AM AS SHORTWAVE ENERGY MOVES INTO THE E DAKOTAS WHILE THE
500MB TROUGH STAYS POSITIVELY TILTED ACROSS THE FOUR CORNERS TO THE
NORTHERN PLAINS. MODEL SOLNS CONTINUE TO AGREE WITH THE MOST QPF
ACROSS THE SOUTH WITH VERY LITTLE IN THE NORTHERN HALF OF THE FA.
TEMPS TO BE IN THE 50S FOR HIGHS FOR THE FIRST HALF OF THE WEEK...AT
TO SLIGHTLY BELOW MID OCT NORMALS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1244 PM CDT THU OCT 10 2013
SCATTERED HIGH CLOUDS THIS AFTERNOON THEN INCREASING AND THICKENING
HIGH CLOUD COVER TONIGHT AS LOW PRESSURE MOVES NORTH INTO WESTERN
NEBRASKA. LOOK FOR THE SOUTHEAST WIND SHIFT LINE TO CONTINUE TO
MOVE NORTH WITH WINDS AT DVL TURNING SOUTHEAST 00Z-02Z PERIOD.
OTHER SITES WILL SEE SOUTHEAST WINDS THRU 12Z IN THE 8 TO 15 KT
RANGE. WINDS WILL INCREASE QUICKLY AFTER SUNRISE FRIDAY AS SURFACE
LOW MOVES TO OUR WEST WITH GUSTS OVER 20 KTS LIKELY OVER THE ENTIRE
AREA WITH GUSTS OVER 25 KTS LIKELY DVL-GFK-FAR IN THE 14-18Z
PERIOD. SOME SHOWER CHANCE IN TO DVL REGION LATE TONIGHT OR EARLY
FRIDAY BUT OTHERWISE MAIN ACTIVITY HOLD OFF TIL PAST 18Z.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
936 AM CDT THU OCT 10 2013
.UPDATE...
ISSUED AT 935 AM CDT THU OCT 10 2013
MAIN FORECAST CONCERN THIS MORNING WILL BE WHICH 12Z MODEL
INITIALIZES BEST FOR PRECIP STARTING LATE TONIGHT INTO FRI
MORNING. 12Z NAM APPEARS TO BE TOO DRY WITH ACTIVITY OVER EASTERN
SD WHILE THE LATEST RUC IS TOO AGGRESSIVE IN BRINGING THAT SHOWERY
ACTIVITY INTO OUR CWA (TOO EARLY IF AT ALL). SO NO PLANS (FROM
LATEST NAM RUN) FOR MAIN SYSTEM WHICH WILL BRING RAIN TO THE AREA
TOMORROW. ONLY FCST CHANGE FOR NOW WILL BE TO FURTHER INCREASE SKY
BASED ON CURRENT SAT TRENDS...MAINLY ACROSS THE NORTHERN HALF OF
CWA. WILL LOOK AT TEMPS CLOSER TO 10 AM BUT NO MAJOR PLANS
EXPECTED FOR DAYTIME HIGHS.
UPDATE ISSUED AT 641 AM CDT THU OCT 10 2013
MADE A FEW TWEAKS TO CLOUDS AS HIGH AND MID LEVEL CLOUDS CONTINUE
TO SPREAD OVER THE AREA ALTHOUGH THERE APPEAR TO BE SOME BREAKS.
TEMPS HAVE STAYED IN THE 40S TO LOW 50S AND THINK EVEN WITH HIGH
CLOUDS WE SHOULD STILL GET INTO THE 60S AND 70S THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT THU OCT 10 2013
TEMPERATURES TODAY AND PRECIP CHANCES TONIGHT AND TOMORROW WILL BE
THE MAIN ISSUES FOR THE SHORT TERM.
WV LOOP SHOWS THE MAIN UPPER LOW DIGGING FROM SOUTHERN CA INTO
AZ...AND THE SYSTEM WILL SWING NORTHEASTWARD INTO THE CENTRAL
ROCKIES LATER TODAY. A WEAK LEAD SHORTWAVE HAS BEEN PRODUCING SOME
SHOWERS OVER NORTHWESTERN ND...BUT THE UPPER FLOW HAS IT TRACKING
INTO CANADA AND STAYING WEST OF US. WILL CONTINUE TO KEEP THE
FORECAST DRY THROUGH 00Z. THERE WILL BE PLENTY OF MID AND HIGH
CLOUDS IN THE SOUTHWESTERLY FLOW OVER THE NORTHERN PLAINS.
INSOLATION WILL BE REDUCED A BIT BUT THERE WILL BE PLENTY OF WARM
AIR ADVECTION AS SOUTHEASTERLY WINDS PICK UP AHEAD OF THE SFC LOW
TODAY. KEPT HIGHS IN THE UPPER 60S TO MID 70S.
THE UPPER LOW WILL BE CLOSING OFF AND MOVING INTO THE SD/NEB
REGION TONIGHT. Q VECTOR CONVERGENCE SHOWS THE BEST SUPPORT WITH
THE UPPER LOW WILL REMAIN MOSTLY TO OUR SOUTHWEST OVERNIGHT...BUT
SOME PRECIP COULD BEGIN TO MOVE INTO THE DEVILS LAKE AREA LATER
ON. MADE ONLY MINOR TWEAKS TO THE 30-40 POPS THAT WE HAD GOING FOR
OUR WESTERN COUNTIES.
THE UPPER LOW WILL BE LIFTING INTO EASTERN ND DURING THE DAY ON
FRIDAY...WITH A FAIRLY STACKED SFC LOW TAKING A SIMILAR TRACK.
THE MODELS STILL HAVE SOME MINOR DIFFERENCES IN EXACTLY WHERE THEY
PUT THE SFC LOW BUT ARE IN BETTER AGREEMENT THAN LAST NIGHT. WITH
STRONG UPPER SUPPORT AS THE SYSTEM MOVES INTO THE AREA CONTINUED
TO KEEP PRETTY HIGH POPS FOR FRIDAY AS SHOWERS AND THUNDERSTORMS
MOVE ACROSS THE AREA IN THE WARM SIDE OF THE SFC LOW. WITH THE
VERY STRONG UPPER SYSTEM...THERE IS THE POSSIBILITY OF SOME LOW
TOPPED SUPERCELLS IF WE GET THE CAPE THAT THE NAM IS
SUGGESTING...AROUND 500 J/KG. MUCH WILL DEPEND ON HOW MUCH CLOUD
COVER WE REALLY END UP WITH...AND SOME OF THE MODELS HAVE NOT MUCH
SFC INSTABILITY AT ALL. WILL INCLUDE A MENTION IN THE HWO FOR
POSSIBILITY OF SEVERE BUT WILL NOT INCLUDE IN GRIDS FOR NOW.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU OCT 10 2013
FRIDAY NIGHT...THE UPPER LOW WILL LIFT OFF INTO CANADA...AND THE
COLD FRONT WILL MOVE THROUGH. WITH THE TIGHT PRESSURE GRADIENT WINDS
WILL BECOME QUITE STRONG AND BE ASSISTED BY COLD AIR ADVECTION ON
THE BACKSIDE OF THE SFC LOW. SO WILL HAVE TO WATCH OUT FOR
ADVISORY CRITERIA EVEN AT NIGHT. SHOWERS WILL CONTINUE MAINLY OVER
THE NORTHERN CWA AS PRECIP WRAPS AROUND THE BACKSIDE OF THE LOW AS
IT LIFTS OUT. THE ECMWF AND GEM KEEP PRECIP A BIT FURTHER WEST
INTO SATURDAY WHILE THE DOMESTIC MODELS JUST KEEP SOME ACTIVITY
OVER THE NORTHEASTERN COUNTIES. WITH CONVECTIVE TEMPS PRETTY LOW
THINK THAT SHOWER ACTIVITY WILL CONTINUE OVER AT LEAST PART OF THE
CWA SO KEPT 20-30 POPS GOING FOR A WHILE EVEN AS SFC HIGH PRESSURE
BUILDS INTO THE AREA. THE SFC HIGH AND COOL AIR WILL HELP SATURDAY
NIGHT DROP BACK INTO THE 30S.
SUNDAY TO WEDNESDAY NIGHT...MODELS IN FAIR AGREEMENT WITH THE
BEGINNING OF NEXT WEEK BRINGING IN THE NEXT STORM SYSTEM ON MONDAY
AND INTO TUESDAY. POPS INCREASED TO LIKELY ACROSS THE S RRV FOR
TUESDAY AM AS SHORTWAVE ENERGY MOVES INTO THE E DAKOTAS WHILE THE
500MB TROUGH STAYS POSITIVELY TILTED ACROSS THE FOUR CORNERS TO THE
NORTHERN PLAINS. MODEL SOLNS CONTINUE TO AGREE WITH THE MOST QPF
ACROSS THE SOUTH WITH VERY LITTLE IN THE NORTHERN HALF OF THE FA.
TEMPS TO BE IN THE 50S FOR HIGHS FOR THE FIRST HALF OF THE WEEK...AT
TO SLIGHTLY BELOW MID OCT NORMALS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CDT THU OCT 10 2013
VFR CIGS CONTINUE OVER THE FORECAST AREA WITH MID AND HIGH CLOUDS
MOSTLY ABOVE 8500 FT. A BIT OF LIGHT FOG BROUGHT VIS AT KTVF TO
4SM...BUT REDUCTIONS HAVE BEEN IN AND OUT AND SHOULD DISAPPEAR
COMPLETELY IN THE NEXT HOUR OR SO. LIGHT WINDS WILL PICK UP OUT OF
THE SOUTHEAST TODAY AND TONIGHT. THERE COULD BE A FEW SHOWERS NEAR
KDVL TOWARDS THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1057 PM CDT FRI OCT 11 2013
.UPDATE...
ISSUED AT 932 PM CDT FRI OCT 11 2013
HAVE CONTINUED TO SEE STEADY SLOW DECLINE IN WINDS ACROSS THE
REMAINDER OF THE AREA THIS EVENING...SO WENT AHEAD AND CANCELLED
REMAINDER OF THE WIND ADVISORY A BIT EARLY. TEMPS/CLOUD COVER STILL
LOOK TO BE IN GOOD SHAPE AND NO REAL CHANGES THERE AT THIS TIME.
UPDATE ISSUED AT 735 PM CDT FRI OCT 11 2013
HAVE CANCELLED PORTIONS OF THE WIND ADVISORY...MAINLY FOR NORTHWEST
IOWA...NORTHEAST NEBRASKA...AND FAR SOUTHEAST SOUTH DAKOTA. ALTHOUGH
MODELS STILL SHOW A SURGE OF COLD ADVECTION AND SOME PRESSURE RISES
MOVING IN BEHIND THE COLD FRONT...SPEEDS THROUGH THE MIXED LAYER IN
THESE AREAS SHOULD BE ON THE LIGHTER SIDE AND NOT SUPPORTIVE OF
ADVISORY CRITERIA. WILL LET THE ADVISORY RIDE ACROSS OUR WEST AND
NORTH FOR NOW...THOUGH EVEN IN THESE AREAS SPEEDS HAVE EASED TO JUST
BELOW ADVISORY CRITERIA WITH SUNSET. WILL MONITOR THESE AREAS FOR
PERSISTENCE OF LOWER SPEEDS...AND MAY CANCEL THEM PRIOR TO 10PM AS
WELL IF THE TREND CONTINUES. REMAINDER OF THE FORECAST LOOKS GOOD FOR
NOW...WITH JUST SOME MINOR CHANGES TO HOURLY TEMPERATURES.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
INTENSE LOW PRESSURE SYSTEM CONTINUES TO MOVE NORTHEAST THROUGH
NORTH CENTRAL SOUTH DAKOTA. THE DRY SLOT CURRENTLY ENCOMPASSES THE
CWA WITH PARTLY SUNNY SKIES. MOST OF THE CONVECTION APPEARS TO BE
FOCUSING NORTH AND EAST OF OUR CWA...AND LATEST HRRR SUPPORTS A
MAINLY DRY AFTERNOON AND EVENING. WINDS WILL REMAIN STRONG WITH
GUSTS OF 40 TO 50 MPH AT TIMES. MAY SEE A SECONDARY SURGE OF
WESTERLY WINDS LATER THIS AFTERNOON INTO THIS EVENING AS THE LOW
MOVES MORE NORTHEAST...AND A PUSH OF COLD AIR ADVECTION MOVES IN.
STRONGEST OF THESE WINDS SHOULD MAINLY STAY ALONG AND WEST OF THE
JAMES RIVER...WHERE GUSTS UP TO 55 MPH COULD OCCUR FOR A TIME INTO
THIS EVENING. WINDS EXPECTED TO BEGIN TO TAPER OFF LATER THIS
EVENING AS ADVECTION BECOMES MORE NEUTRAL AND WE ARE ABLE TO
DECOUPLE A BIT AT THE SURFACE. SO FOR NOW ENDING THE ADVISORY AT 03Z
SEEMS OK. BUT WILL HAVE TO MONITOR...AS IF WE STAY MIXED LONGER
COULD SEE ADVISORY CRITERIA LINGER A BIT LONGER INTO THE NIGHT. SOME
STRATUS WILL LIKELY REENTER THE CWA BEHIND THE LOW OVERNIGHT AS
WELL. THINK LOWS WILL END UP CLOSER TO THE WARMER RAW GUIDANCE GIVEN
THE MIXED STATE OF THE ATMOSPHERE. LOOKING AT READINGS IN THE MID
40S. STRATUS MAY LINGER NORTH OF INTERSTATE 90 THROUGH THE
MORNING...BUT OVERALL SHOULD SEE INCREASING SUN THROUGH THE DAY
TOMORROW. COULD ALSO SEE A FEW ISOLATED SHOWERS ALONG THE HIGHWAY 14
CORRIDOR IN THE MORNING AS THE TROUGH AXIS SWINGS THROUGH. WESTERLY
WINDS WILL REMAIN BLUSTERY...WITH GUSTS OF 25 TO 40 MPH. SOUTHWEST
MINNESOTA MAY APPROACH WIND ADVISORY CRITERIA. WILL HOLD OFF ON ANY
HEADLINE AT THIS POINT...BUT OVERNIGHT SHIFT WILL HAVE TO TAKE
ANOTHER LOOK. HIGHS SHOULD RANGE FROM THE UPPER 50S TO MID 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
MILD DAY EXPECTED ACROSS THE REGION ON SUNDAY WITH RIDGING SLIDING
OFF TO OUR EAST AND SOUTHWEST UPPER LEVEL FLOW SETTING UP AHEAD OF
THE NEXT STORM SYSTEM. WINDS WILL BE SOMEWHAT BREEZY IN THE
AFTERNOON FROM THE SOUTHEAST...BUT COPIOUS SUNSHINE SHOULD ALLOW
AFTERNOON TEMPERATURES TO CLIMB INTO THE LOW TO MID 60S. WITH WINDS
EXPECTED TO BECOME LIGHT AND VARIABLE OVERNIGHT UNDER MOSTLY CLEAR
SKIES...LEFT MENTION OF SOME PATCHY FOG LATE SUNDAY NIGHT/EARLY
MONDAY WITH TEMPERATURES FALLING INTO THE MID 30S.
LARGE UPPER LEVEL LOW DIGS INTO THE GREAT BASIN SUNDAY AND OPENS
INTO THE NORTHERN PLAINS BY MONDAY AFTERNOON. ASSOCIATED SURFACE LOW
DEEPENS OVER THE CENTRAL HIGH PLAINS MONDAY AND SLOWLY LIFTS
NORTHEASTWARD MONDAY NIGHT AND TUESDAY...REACHING NORTHERN WISCONSIN
BY AROUND TUESDAY AFTERNOON. STILL A BIT OF UNCERTAINTY WITH THE
TIMING AND TRACK OF THIS SYSTEM...MOST NOTABLY WITH THE ECMWF
SLOWING THE UPPER LEVEL FEATURE AND LINGERING IT OVER OUR VICINITY
MUCH LONGER. AS IT STANDS...ALL MODELS POINT TO A VERY WET AND COOL
PATTERN EARLY NEXT WEEK. INSTABILITY IS PRETTY WEAK WITH THIS
SYSTEM...SO DO NOT ANTICIPATE MUCH MORE THAN A FEW EMBEDDED NON
SEVERE STORMS. WINDS WILL LIKELY ALSO BE STRONG AGAIN WITH THIS
SYSTEM. WHILE TEMPERATURES DO COOL SIGNIFICANTLY...PRECIPITATION
LOOKS TO REMAIN ENTIRELY RAIN. HIGHS WILL BE IN THE 40S AND 50S WITH
VERY LITTLE DIURNAL RANGE.
REMOVED MENTION OF SOME VERY LOW END POPS PRODUCED BY THE ALLBLEND
WEDNESDAY AND BEYOND WITH QUITE A BIT OF UNCERTAINTY THERE. BUT IF
THE ECMWF PANS OUT...COULD SEE WET AND CLOUDY CONDITIONS LINGER INTO
MIDWEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1056 PM CDT FRI OCT 11 2013
GUSTY WINDS REMAIN THE PRIMARY AVIATION CONCERN TONIGHT THROUGH THE
DAYLIGHT HOURS SATURDAY. STRONGEST WINDS THROUGH THE PERIOD WILL BE
NORTH OF I-90...WHERE GUSTS OF 20-30KT ARE EXPECTED OVERNIGHT...AND
GUSTS OF 30-35KT WILL BE FREQUENT AFTER 14Z-15Z SATURDAY. SOMEWHAT
LIGHTER WINDS ARE EXPECTED ALONG AND SOUTH OF I-90...THOUGH EVEN
THERE GUSTS OF 20-30KT WILL BE COMMON DURING THE DAY SATURDAY. ALL
AREAS WILL SEE WINDS QUICKLY DIMINISH DURING THE LATE AFTERNOON...
WITH SPEEDS GENERALLY AT OR BELOW 10KT AFTER 13/00Z. SOME LINGERING
MVFR CEILINGS NORTH OF I-90 AND EAST OF THE JAMES RIVER AT THE START
OF THIS TAF PERIOD...AND THIS AREA COULD CONTINUE TO SEE PERIODS OF
MVFR CEILINGS THROUGH 16Z-18Z SATURDAY. OTHERWISE VFR CONDITIONS WILL
DOMINATE ACROSS THE AREA THROUGH THE PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...JH
SHORT TERM...CHENARD
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
932 PM CDT FRI OCT 11 2013
.UPDATE...
ISSUED AT 932 PM CDT FRI OCT 11 2013
HAVE CONTINUED TO SEE STEADY SLOW DECLINE IN WINDS ACROSS THE
REMAINDER OF THE AREA THIS EVENING...SO WENT AHEAD AND CANCELLED
REMAINDER OF THE WIND ADVISORY A BIT EARLY. TEMPS/CLOUD COVER STILL
LOOK TO BE IN GOOD SHAPE AND NO REAL CHANGES THERE AT THIS TIME.
UPDATE ISSUED AT 735 PM CDT FRI OCT 11 2013
HAVE CANCELLED PORTIONS OF THE WIND ADVISORY...MAINLY FOR NORTHWEST
IOWA...NORTHEAST NEBRASKA...AND FAR SOUTHEAST SOUTH DAKOTA. ALTHOUGH
MODELS STILL SHOW A SURGE OF COLD ADVECTION AND SOME PRESSURE RISES
MOVING IN BEHIND THE COLD FRONT...SPEEDS THROUGH THE MIXED LAYER IN
THESE AREAS SHOULD BE ON THE LIGHTER SIDE AND NOT SUPPORTIVE OF
ADVISORY CRITERIA. WILL LET THE ADVISORY RIDE ACROSS OUR WEST AND
NORTH FOR NOW...THOUGH EVEN IN THESE AREAS SPEEDS HAVE EASED TO JUST
BELOW ADVISORY CRITERIA WITH SUNSET. WILL MONITOR THESE AREAS FOR
PERSISTENCE OF LOWER SPEEDS...AND MAY CANCEL THEM PRIOR TO 10PM AS
WELL IF THE TREND CONTINUES. REMAINDER OF THE FORECAST LOOKS GOOD FOR
NOW...WITH JUST SOME MINOR CHANGES TO HOURLY TEMPERATURES.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
INTENSE LOW PRESSURE SYSTEM CONTINUES TO MOVE NORTHEAST THROUGH
NORTH CENTRAL SOUTH DAKOTA. THE DRY SLOT CURRENTLY ENCOMPASSES THE
CWA WITH PARTLY SUNNY SKIES. MOST OF THE CONVECTION APPEARS TO BE
FOCUSING NORTH AND EAST OF OUR CWA...AND LATEST HRRR SUPPORTS A
MAINLY DRY AFTERNOON AND EVENING. WINDS WILL REMAIN STRONG WITH
GUSTS OF 40 TO 50 MPH AT TIMES. MAY SEE A SECONDARY SURGE OF
WESTERLY WINDS LATER THIS AFTERNOON INTO THIS EVENING AS THE LOW
MOVES MORE NORTHEAST...AND A PUSH OF COLD AIR ADVECTION MOVES IN.
STRONGEST OF THESE WINDS SHOULD MAINLY STAY ALONG AND WEST OF THE
JAMES RIVER...WHERE GUSTS UP TO 55 MPH COULD OCCUR FOR A TIME INTO
THIS EVENING. WINDS EXPECTED TO BEGIN TO TAPER OFF LATER THIS
EVENING AS ADVECTION BECOMES MORE NEUTRAL AND WE ARE ABLE TO
DECOUPLE A BIT AT THE SURFACE. SO FOR NOW ENDING THE ADVISORY AT 03Z
SEEMS OK. BUT WILL HAVE TO MONITOR...AS IF WE STAY MIXED LONGER
COULD SEE ADVISORY CRITERIA LINGER A BIT LONGER INTO THE NIGHT. SOME
STRATUS WILL LIKELY REENTER THE CWA BEHIND THE LOW OVERNIGHT AS
WELL. THINK LOWS WILL END UP CLOSER TO THE WARMER RAW GUIDANCE GIVEN
THE MIXED STATE OF THE ATMOSPHERE. LOOKING AT READINGS IN THE MID
40S. STRATUS MAY LINGER NORTH OF INTERSTATE 90 THROUGH THE
MORNING...BUT OVERALL SHOULD SEE INCREASING SUN THROUGH THE DAY
TOMORROW. COULD ALSO SEE A FEW ISOLATED SHOWERS ALONG THE HIGHWAY 14
CORRIDOR IN THE MORNING AS THE TROUGH AXIS SWINGS THROUGH. WESTERLY
WINDS WILL REMAIN BLUSTERY...WITH GUSTS OF 25 TO 40 MPH. SOUTHWEST
MINNESOTA MAY APPROACH WIND ADVISORY CRITERIA. WILL HOLD OFF ON ANY
HEADLINE AT THIS POINT...BUT OVERNIGHT SHIFT WILL HAVE TO TAKE
ANOTHER LOOK. HIGHS SHOULD RANGE FROM THE UPPER 50S TO MID 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
MILD DAY EXPECTED ACROSS THE REGION ON SUNDAY WITH RIDGING SLIDING
OFF TO OUR EAST AND SOUTHWEST UPPER LEVEL FLOW SETTING UP AHEAD OF
THE NEXT STORM SYSTEM. WINDS WILL BE SOMEWHAT BREEZY IN THE
AFTERNOON FROM THE SOUTHEAST...BUT COPIOUS SUNSHINE SHOULD ALLOW
AFTERNOON TEMPERATURES TO CLIMB INTO THE LOW TO MID 60S. WITH WINDS
EXPECTED TO BECOME LIGHT AND VARIABLE OVERNIGHT UNDER MOSTLY CLEAR
SKIES...LEFT MENTION OF SOME PATCHY FOG LATE SUNDAY NIGHT/EARLY
MONDAY WITH TEMPERATURES FALLING INTO THE MID 30S.
LARGE UPPER LEVEL LOW DIGS INTO THE GREAT BASIN SUNDAY AND OPENS
INTO THE NORTHERN PLAINS BY MONDAY AFTERNOON. ASSOCIATED SURFACE LOW
DEEPENS OVER THE CENTRAL HIGH PLAINS MONDAY AND SLOWLY LIFTS
NORTHEASTWARD MONDAY NIGHT AND TUESDAY...REACHING NORTHERN WISCONSIN
BY AROUND TUESDAY AFTERNOON. STILL A BIT OF UNCERTAINTY WITH THE
TIMING AND TRACK OF THIS SYSTEM...MOST NOTABLY WITH THE ECMWF
SLOWING THE UPPER LEVEL FEATURE AND LINGERING IT OVER OUR VICINITY
MUCH LONGER. AS IT STANDS...ALL MODELS POINT TO A VERY WET AND COOL
PATTERN EARLY NEXT WEEK. INSTABILITY IS PRETTY WEAK WITH THIS
SYSTEM...SO DO NOT ANTICIPATE MUCH MORE THAN A FEW EMBEDDED NON
SEVERE STORMS. WINDS WILL LIKELY ALSO BE STRONG AGAIN WITH THIS
SYSTEM. WHILE TEMPERATURES DO COOL SIGNIFICANTLY...PRECIPITATION
LOOKS TO REMAIN ENTIRELY RAIN. HIGHS WILL BE IN THE 40S AND 50S WITH
VERY LITTLE DIURNAL RANGE.
REMOVED MENTION OF SOME VERY LOW END POPS PRODUCED BY THE ALLBLEND
WEDNESDAY AND BEYOND WITH QUITE A BIT OF UNCERTAINTY THERE. BUT IF
THE ECMWF PANS OUT...COULD SEE WET AND CLOUDY CONDITIONS LINGER INTO
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 651 PM CDT FRI OCT 11 2013
GUSTY WINDS WILL BE THE PRIMARY AVIATION CONCERN THROUGH THIS PERIOD.
GUSTS WILL GENERALLY BE IN THE 20-30KT RANGE THROUGH THE PERIOD...
WITH THE STRONGEST WINDS THIS EVENING THROUGH 03Z-04Z...AND AGAIN
AFTER 14Z-15Z SATURDAY AS DEEPER MIXING ONCE AGAIN COMMENCES. THE
WINDS SHOULD BEGIN TO DIMINISH QUICKLY AFTER 22Z-23Z SATURDAY WITH
SURFACE RIDGE BRINGING QUICK DECOUPLING TOWARD SUNSET. ASIDE FROM THE
WINDS...GENERALLY VFR CONDITIONS WILL PREVAIL...THOUGH MVFR CEILINGS
WILL ROTATE THROUGH AREAS NORTH OF INTERSTATE 90 THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...JH
SHORT TERM...CHENARD
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
735 PM CDT FRI OCT 11 2013
.UPDATE...
ISSUED AT 735 PM CDT FRI OCT 11 2013
HAVE CANCELLED PORTIONS OF THE WIND ADVISORY...MAINLY FOR NORTHWEST
IOWA...NORTHEAST NEBRASKA...AND FAR SOUTHEAST SOUTH DAKOTA. ALTHOUGH
MODELS STILL SHOW A SURGE OF COLD ADVECTION AND SOME PRESSURE RISES
MOVING IN BEHIND THE COLD FRONT...SPEEDS THROUGH THE MIXED LAYER IN
THESE AREAS SHOULD BE ON THE LIGHTER SIDE AND NOT SUPPORTIVE OF
ADVISORY CRITERIA. WILL LET THE ADVISORY RIDE ACROSS OUR WEST AND
NORTH FOR NOW...THOUGH EVEN IN THESE AREAS SPEEDS HAVE EASED TO JUST
BELOW ADVISORY CRITERIA WITH SUNSET. WILL MONITOR THESE AREAS FOR
PERSISTENCE OF LOWER SPEEDS...AND MAY CANCEL THEM PRIOR TO 10PM AS
WELL IF THE TREND CONTINUES. REMAINDER OF THE FORECAST LOOKS GOOD FOR
NOW...WITH JUST SOME MINOR CHANGES TO HOURLY TEMPERATURES.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
INTENSE LOW PRESSURE SYSTEM CONTINUES TO MOVE NORTHEAST THROUGH
NORTH CENTRAL SOUTH DAKOTA. THE DRY SLOT CURRENTLY ENCOMPASSES THE
CWA WITH PARTLY SUNNY SKIES. MOST OF THE CONVECTION APPEARS TO BE
FOCUSING NORTH AND EAST OF OUR CWA...AND LATEST HRRR SUPPORTS A
MAINLY DRY AFTERNOON AND EVENING. WINDS WILL REMAIN STRONG WITH
GUSTS OF 40 TO 50 MPH AT TIMES. MAY SEE A SECONDARY SURGE OF
WESTERLY WINDS LATER THIS AFTERNOON INTO THIS EVENING AS THE LOW
MOVES MORE NORTHEAST...AND A PUSH OF COLD AIR ADVECTION MOVES IN.
STRONGEST OF THESE WINDS SHOULD MAINLY STAY ALONG AND WEST OF THE
JAMES RIVER...WHERE GUSTS UP TO 55 MPH COULD OCCUR FOR A TIME INTO
THIS EVENING. WINDS EXPECTED TO BEGIN TO TAPER OFF LATER THIS
EVENING AS ADVECTION BECOMES MORE NEUTRAL AND WE ARE ABLE TO
DECOUPLE A BIT AT THE SURFACE. SO FOR NOW ENDING THE ADVISORY AT 03Z
SEEMS OK. BUT WILL HAVE TO MONITOR...AS IF WE STAY MIXED LONGER
COULD SEE ADVISORY CRITERIA LINGER A BIT LONGER INTO THE NIGHT. SOME
STRATUS WILL LIKELY REENTER THE CWA BEHIND THE LOW OVERNIGHT AS
WELL. THINK LOWS WILL END UP CLOSER TO THE WARMER RAW GUIDANCE GIVEN
THE MIXED STATE OF THE ATMOSPHERE. LOOKING AT READINGS IN THE MID
40S. STRATUS MAY LINGER NORTH OF INTERSTATE 90 THROUGH THE
MORNING...BUT OVERALL SHOULD SEE INCREASING SUN THROUGH THE DAY
TOMORROW. COULD ALSO SEE A FEW ISOLATED SHOWERS ALONG THE HIGHWAY 14
CORRIDOR IN THE MORNING AS THE TROUGH AXIS SWINGS THROUGH. WESTERLY
WINDS WILL REMAIN BLUSTERY...WITH GUSTS OF 25 TO 40 MPH. SOUTHWEST
MINNESOTA MAY APPROACH WIND ADVISORY CRITERIA. WILL HOLD OFF ON ANY
HEADLINE AT THIS POINT...BUT OVERNIGHT SHIFT WILL HAVE TO TAKE
ANOTHER LOOK. HIGHS SHOULD RANGE FROM THE UPPER 50S TO MID 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
MILD DAY EXPECTED ACROSS THE REGION ON SUNDAY WITH RIDGING SLIDING
OFF TO OUR EAST AND SOUTHWEST UPPER LEVEL FLOW SETTING UP AHEAD OF
THE NEXT STORM SYSTEM. WINDS WILL BE SOMEWHAT BREEZY IN THE
AFTERNOON FROM THE SOUTHEAST...BUT COPIOUS SUNSHINE SHOULD ALLOW
AFTERNOON TEMPERATURES TO CLIMB INTO THE LOW TO MID 60S. WITH WINDS
EXPECTED TO BECOME LIGHT AND VARIABLE OVERNIGHT UNDER MOSTLY CLEAR
SKIES...LEFT MENTION OF SOME PATCHY FOG LATE SUNDAY NIGHT/EARLY
MONDAY WITH TEMPERATURES FALLING INTO THE MID 30S.
LARGE UPPER LEVEL LOW DIGS INTO THE GREAT BASIN SUNDAY AND OPENS
INTO THE NORTHERN PLAINS BY MONDAY AFTERNOON. ASSOCIATED SURFACE LOW
DEEPENS OVER THE CENTRAL HIGH PLAINS MONDAY AND SLOWLY LIFTS
NORTHEASTWARD MONDAY NIGHT AND TUESDAY...REACHING NORTHERN WISCONSIN
BY AROUND TUESDAY AFTERNOON. STILL A BIT OF UNCERTAINTY WITH THE
TIMING AND TRACK OF THIS SYSTEM...MOST NOTABLY WITH THE ECMWF
SLOWING THE UPPER LEVEL FEATURE AND LINGERING IT OVER OUR VICINITY
MUCH LONGER. AS IT STANDS...ALL MODELS POINT TO A VERY WET AND COOL
PATTERN EARLY NEXT WEEK. INSTABILITY IS PRETTY WEAK WITH THIS
SYSTEM...SO DO NOT ANTICIPATE MUCH MORE THAN A FEW EMBEDDED NON
SEVERE STORMS. WINDS WILL LIKELY ALSO BE STRONG AGAIN WITH THIS
SYSTEM. WHILE TEMPERATURES DO COOL SIGNIFICANTLY...PRECIPITATION
LOOKS TO REMAIN ENTIRELY RAIN. HIGHS WILL BE IN THE 40S AND 50S WITH
VERY LITTLE DIURNAL RANGE.
REMOVED MENTION OF SOME VERY LOW END POPS PRODUCED BY THE ALLBLEND
WEDNESDAY AND BEYOND WITH QUITE A BIT OF UNCERTAINTY THERE. BUT IF
THE ECMWF PANS OUT...COULD SEE WET AND CLOUDY CONDITIONS LINGER INTO
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 651 PM CDT FRI OCT 11 2013
GUSTY WINDS WILL BE THE PRIMARY AVIATION CONCERN THROUGH THIS PERIOD.
GUSTS WILL GENERALLY BE IN THE 20-30KT RANGE THROUGH THE PERIOD...
WITH THE STRONGEST WINDS THIS EVENING THROUGH 03Z-04Z...AND AGAIN
AFTER 14Z-15Z SATURDAY AS DEEPER MIXING ONCE AGAIN COMMENCES. THE
WINDS SHOULD BEGIN TO DIMINISH QUICKLY AFTER 22Z-23Z SATURDAY WITH
SURFACE RIDGE BRINGING QUICK DECOUPLING TOWARD SUNSET. ASIDE FROM THE
WINDS...GENERALLY VFR CONDITIONS WILL PREVAIL...THOUGH MVFR CEILINGS
WILL ROTATE THROUGH AREAS NORTH OF INTERSTATE 90 THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR SDZ038>040-050-
052>065.
MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ071-072-080-
081-089-090-097-098.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...JH
SHORT TERM...CHENARD
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
651 PM CDT FRI OCT 11 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
INTENSE LOW PRESSURE SYSTEM CONTINUES TO MOVE NORTHEAST THROUGH
NORTH CENTRAL SOUTH DAKOTA. THE DRY SLOT CURRENTLY ENCOMPASSES THE
CWA WITH PARTLY SUNNY SKIES. MOST OF THE CONVECTION APPEARS TO BE
FOCUSING NORTH AND EAST OF OUR CWA...AND LATEST HRRR SUPPORTS A
MAINLY DRY AFTERNOON AND EVENING. WINDS WILL REMAIN STRONG WITH
GUSTS OF 40 TO 50 MPH AT TIMES. MAY SEE A SECONDARY SURGE OF
WESTERLY WINDS LATER THIS AFTERNOON INTO THIS EVENING AS THE LOW
MOVES MORE NORTHEAST...AND A PUSH OF COLD AIR ADVECTION MOVES IN.
STRONGEST OF THESE WINDS SHOULD MAINLY STAY ALONG AND WEST OF THE
JAMES RIVER...WHERE GUSTS UP TO 55 MPH COULD OCCUR FOR A TIME INTO
THIS EVENING. WINDS EXPECTED TO BEGIN TO TAPER OFF LATER THIS
EVENING AS ADVECTION BECOMES MORE NEUTRAL AND WE ARE ABLE TO
DECOUPLE A BIT AT THE SURFACE. SO FOR NOW ENDING THE ADVISORY AT 03Z
SEEMS OK. BUT WILL HAVE TO MONITOR...AS IF WE STAY MIXED LONGER
COULD SEE ADVISORY CRITERIA LINGER A BIT LONGER INTO THE NIGHT. SOME
STRATUS WILL LIKELY REENTER THE CWA BEHIND THE LOW OVERNIGHT AS
WELL. THINK LOWS WILL END UP CLOSER TO THE WARMER RAW GUIDANCE GIVEN
THE MIXED STATE OF THE ATMOSPHERE. LOOKING AT READINGS IN THE MID
40S. STRATUS MAY LINGER NORTH OF INTERSTATE 90 THROUGH THE
MORNING...BUT OVERALL SHOULD SEE INCREASING SUN THROUGH THE DAY
TOMORROW. COULD ALSO SEE A FEW ISOLATED SHOWERS ALONG THE HIGHWAY 14
CORRIDOR IN THE MORNING AS THE TROUGH AXIS SWINGS THROUGH. WESTERLY
WINDS WILL REMAIN BLUSTERY...WITH GUSTS OF 25 TO 40 MPH. SOUTHWEST
MINNESOTA MAY APPROACH WIND ADVISORY CRITERIA. WILL HOLD OFF ON ANY
HEADLINE AT THIS POINT...BUT OVERNIGHT SHIFT WILL HAVE TO TAKE
ANOTHER LOOK. HIGHS SHOULD RANGE FROM THE UPPER 50S TO MID 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 PM CDT FRI OCT 11 2013
MILD DAY EXPECTED ACROSS THE REGION ON SUNDAY WITH RIDGING SLIDING
OFF TO OUR EAST AND SOUTHWEST UPPER LEVEL FLOW SETTING UP AHEAD OF
THE NEXT STORM SYSTEM. WINDS WILL BE SOMEWHAT BREEZY IN THE
AFTERNOON FROM THE SOUTHEAST...BUT COPIOUS SUNSHINE SHOULD ALLOW
AFTERNOON TEMPERATURES TO CLIMB INTO THE LOW TO MID 60S. WITH WINDS
EXPECTED TO BECOME LIGHT AND VARIABLE OVERNIGHT UNDER MOSTLY CLEAR
SKIES...LEFT MENTION OF SOME PATCHY FOG LATE SUNDAY NIGHT/EARLY
MONDAY WITH TEMPERATURES FALLING INTO THE MID 30S.
LARGE UPPER LEVEL LOW DIGS INTO THE GREAT BASIN SUNDAY AND OPENS
INTO THE NORTHERN PLAINS BY MONDAY AFTERNOON. ASSOCIATED SURFACE LOW
DEEPENS OVER THE CENTRAL HIGH PLAINS MONDAY AND SLOWLY LIFTS
NORTHEASTWARD MONDAY NIGHT AND TUESDAY...REACHING NORTHERN WISCONSIN
BY AROUND TUESDAY AFTERNOON. STILL A BIT OF UNCERTAINTY WITH THE
TIMING AND TRACK OF THIS SYSTEM...MOST NOTABLY WITH THE ECMWF
SLOWING THE UPPER LEVEL FEATURE AND LINGERING IT OVER OUR VICINITY
MUCH LONGER. AS IT STANDS...ALL MODELS POINT TO A VERY WET AND COOL
PATTERN EARLY NEXT WEEK. INSTABILITY IS PRETTY WEAK WITH THIS
SYSTEM...SO DO NOT ANTICIPATE MUCH MORE THAN A FEW EMBEDDED NON
SEVERE STORMS. WINDS WILL LIKELY ALSO BE STRONG AGAIN WITH THIS
SYSTEM. WHILE TEMPERATURES DO COOL SIGNIFICANTLY...PRECIPITATION
LOOKS TO REMAIN ENTIRELY RAIN. HIGHS WILL BE IN THE 40S AND 50S WITH
VERY LITTLE DIURNAL RANGE.
REMOVED MENTION OF SOME VERY LOW END POPS PRODUCED BY THE ALLBLEND
WEDNESDAY AND BEYOND WITH QUITE A BIT OF UNCERTAINTY THERE. BUT IF
THE ECMWF PANS OUT...COULD SEE WET AND CLOUDY CONDITIONS LINGER INTO
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 651 PM CDT FRI OCT 11 2013
GUSTY WINDS WILL BE THE PRIMARY AVIATION CONCERN THROUGH THIS PERIOD.
GUSTS WILL GENERALLY BE IN THE 20-30KT RANGE THROUGH THE PERIOD...
WITH THE STRONGEST WINDS THIS EVENING THROUGH 03Z-04Z...AND AGAIN
AFTER 14Z-15Z SATURDAY AS DEEPER MIXING ONCE AGAIN COMMENCES. THE
WINDS SHOULD BEGIN TO DIMINISH QUICKLY AFTER 22Z-23Z SATURDAY WITH
SURFACE RIDGE BRINGING QUICK DECOUPLING TOWARD SUNSET. ASIDE FROM THE
WINDS...GENERALLY VFR CONDITIONS WILL PREVAIL...THOUGH MVFR CEILINGS
WILL ROTATE THROUGH AREAS NORTH OF INTERSTATE 90 THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR SDZ038>040-050-
052>071.
MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ071-072-080-
081-089-090-097-098.
IA...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR IAZ001>003-
012>014-020>022-031-032.
NE...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR NEZ013-014.
&&
$$
SHORT TERM...CHENARD
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
955 PM CDT FRI OCT 11 2013
.UPDATE...
SECOND LINE OF SHOWERS THAT HRRR AND SOME OF THE OTHER HI-RES
MODELS HAVE BEEN SHOWING FORMING EAST OF THE MAIN NARROW BAND IN
MN/IA LOOKS TO BE STRUGGLING A BIT. LATEST NAM ON TRACK WITH
CURRENT FORECAST TIMING. WILL LEAVE POPS AS IS WITH THE BETTER
CHANCE FOR LIGHT MEASURABLE PCPN IN CONVERGENCE ZONE ALONG SURFACE
TROUGH/OCCLUSION WHICH REACHES WESTERN AREAS AROUND 10Z.
&&
.AVIATION/06Z TAFS/...
GRADIENT WINDS SHOULD LIMIT CHANCE FOR ANY FOG TONIGHT. MODELS
STILL SHOWING 3-HOUR WINDOW OF OPPORTUNITY FOR SHOWERS WILL BE
BETWEEN 10Z AND 13Z AT KMSN...11Z TO 14Z AT KUES AND 12Z TO 15Z AT
KMKE AND KENW. HI-RES MODELS TRYING TO FORM A LINE OF SCATTERED
SHOWERS OUT AHEAD OF THE NARROW MAIN BAND...BUT IT IS STRUGGLING
ON AREA RADAR LOOPS. WILL MAKE NEEDED ADJUSTMENTS WITH TIMING
CLOSER TO ISSUANCE TIME. OTHERWISE VFR CONDITIONS WITH ONLY BRIEF
MVFR VSBYS IN SHOWERS.
&&
.MARINE...
SE 10 TO 15 KNOT WINDS EXPECTED TO SHIFT SOUTH AND INCREASE TO 10 TO
20 KNOTS...POSSIBLY 15 TO 20 KNOTS IN NRN ZONES AROUND/AFTER
MIDNIGHT. WAVE HEIGHTS OF 3 TO 5 FEET NORTH OF PORT WASHINGTON EXPECTED
UNTIL WINDS TURN SOUTHWEST AND LOWER EARLY IN THE AFTERNOON...THEN
VEER WEST LATE IN THE AFTERNOON. TIMING OF SMALL CRAFT ADVISORY
FOR WAVES LOOKS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 355 PM CDT FRI OCT 11 2013/
VERY SHORT TERM...TONIGHT AND SATURDAY.
MAIN CONCERNS WERE POPS/WX...TEMPS...AND DEW POINTS THIS PERIOD. OF
WHICH...FEATURES A COLD FRONT PASSING THROUGH THE CWA SATURDAY.
DIURNALLY DRIVEN CU EXPECTED TO DISSIPATE WITH THE LOSS OF DAYTIME
HEATING THIS EVENING. THEN WILL HAVE A PERIOD OF REDUCED SKY COVER
BEFORE CLOUDS UPSTREAM ASSOCIATED WITH SFC LOW PRESSURE IN THE
NORTHERN GREAT PLAINS MOVES IN. CURRENT THINKING IS THE BEST CHANCES
FOR PRECIP WILL BE BETWEEN 12 AND 18 UTC GIVEN THE SHORT WAVE TROUGH
AND ASSOCIATED VORT MAX AND THE BEST FRONTOGENETICAL RESPONSE.
INCLUDED ISOLATE THUNDER DURING THE DAY GIVEN THE MARGINAL ELEVATED
POTENTIAL INSTABILITY PRESENT.
SHORT TERM...SATURDAY NIGHT THROUGH MONDAY.
A QUIET AND PLEASANT PERIOD IS EXPECTED FOR MID-OCTOBER AS SHORT
WAVE RIDGING AND WEAK HIGH PRESSURE PASSES ACROSS THE REGION. DRY
AIR WILL ACCOMPANY THE HIGH PRESSURE. 925H TEMPS FALL TO AROUND 8C
FOR MUCH OF THE PERIOD. EXPECTING CLEAR TO M/CLR CONDITIONS FOR MUCH
OF THE PERIOD INLAND. MOST CONCERNED ABOUT A PERIOD OF LAKE CLOUDS
AFFECTING ERN AREAS LATER SUN NGT INTO MONDAY MORNING AS DELTA-T
INCREASES TO 11 TO 14C. BOTH GFS AND NAM CROSS-SECTIONS SHOW
INCREASE IN LOW LEVEL RH DURING THIS PERIOD...HOWEVER INCREASE IN RH
SHALLOW AROUND 3K FEET. ALSO...LOW LEVEL WINDS VEER MOST OF THE
NIGHT AND BECOME E-SELY LATER MONDAY MORNING. HENCE IF LOW CLOUDS
DO DEVELOP...EXPECT THE BKN DECK TO LINGER FOR ONLY A SHORT PERIOD
OF TIME.
RIDGE AXIS REMAINS WEST OF THE AREA SUNDAY NIGHT...SO THINKING
BOUNDARY LAYER MIXING SHOULD PREVENT MOST FROST EXCEPT IN FAVORABLE
LOW AREAS OF WRN CWA. FAVORABLE SETUP HOWEVER FOR FOG IN THE WI
RIVER VALLEY.
BETTER CHANCE FOR LIGHT BOUNDARY LAYER WINDS OVER A GOOD PORTION OF
THE NIGHT SUNDAY NIGHT AS RIDGE SPRAWLS ACROSS WISCONSIN. HENCE
ADDED PATCHY FROST MOST INLAND AREAS BUT KEPT IT OUT OF THE EAST DUE
TO POTENTIAL PATCHY LAKE CLOUDS AND HIGHER DEWPTS FROM MARINE
LAYER. OVERNIGHT LOWS AWAY FROM THE LAKE EXPECTED IN THE MIDDLE TO
UPPER 30S WITH SOME ISOLATED LOW 30S.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
REVIEWING SUCCESSIVE RUNS OF LONG TERM GUIDANCE...APPEARS
APPROACHING AMPLIFYING SHORT WAVE TROUGH SLOWING DOWN AND GATHERING
STRENGTH UPSTREAM OVER THE CENTRAL PLAINS ON MONDAY AND TUESDAY.
DEEPENING MOISTURE BEING PULLED NORTHWARD AHEAD OF THIS SYSTEM
DELAYED SOMEWHAT BY SLOWER MOVEMENT AND PERSISTENT DRY EAST FLOW.
HENCE WL BE ABLE TO ADD TIGHTER GRADIENT TO PRECIP CHANCE PUSHING IN
MONDAY NIGHT. UPPER LOW BEGINS TO OCCLUDE AND SLOWLY WEAKEN AS IT
PROGRESSES NORTHEAST ACROSS WISCONSIN ON WED. WILL NEED TO KEEP
CHANCES IN FOR -SHRA INTO WED AS LOW PASSES BY. BEST CHANCE FOR
PRECIP STILL LOOKS TO BE TUE WHEN PRECIPITABLE WATER VALUES INCREASE
TO OVER 1 INCH AS STRONGER WARM AIR ADVECTION PASSES THROUGH. NOT
SEEING MUCH ELEVATED INSTABILITY SO WL HOLD OFF ON THUNDER MENTION
FOR NOW.
INCREASING NORTHWEST FLOW IN THE WAKE OF THIS SYSTEM WILL USHER
COLDER AIR INTO SOUTHERN WI FOR THE LATER PERIODS. UPSTREAM SHORT
WAVE MOVING ACROSS SOUTHERN CANADA INTO CENTRAL CONUS SHOULD KEEP
UPPER LOW PROGRESSIVE AND MOVING NORTHEAST. HOWEVER CONSIDERABLE
UNCERTAINTY AS TO THE TRACK OF THE FOLLOWING SHORT WAVE TROF IN THE
EXTENDED GUIDANCE. LATEST ECMWF TAKES PIECE OF SHORT WAVE ENERGY
ACROSS WESTERN CONUS INTO SOUTHWEST BY FRIDAY WITH SLIGHTLY MILDER
SOUTHWEST FLOW ALOFT SETTING UP INTO THE GREAT LAKES. GFS HAS
CANADIAN ENERGY DIGGING SOUTHWEST INTO CENTRAL CONUS...AMPLIFYING
LONG WAVE TROF IN THIS AREA. GFS 5 DAY MEANS OF 500H STILL HAS
NEGATIVE HEIGHT ANOMOLY OF OVER 100 METERS CENTERED OVER WI AT
00Z/19 AND REMAINING OVER THE AREA THROUGH THE 22ND. GFS ENSEMBLE
HEIGHTS ABOUT SPLIT ON STRENGTH OF LONG WAVE TROFFING AND RESULTANT
COLD AIR OVER UPPER MIDWEST BY THE END OF THE WEEK.
NEVER THE LESS...CLEAR SKIES AND LIGHTER WINDS LATER NEXT WEEK
SHOULD RESULT IN A GREATER POTENTIAL FOR WIDESPREAD FROST AND
FREEZING TEMPS.
AVIATION /00Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH THE
ENTIRE PERIOD. DIURNALLY DRIVEN CLOUDS WILL DISSIPATE THIS EVENING
AND THIS WILL RESULT IN PERIOD OF LESS CLOUD COVER BEFORE CLOUDS
UPSTREAM MOVE IN THAT ARE ASSOCIATED WITH A LOW PRESSURE SYSTEM IN
THE NORTHERN GREAT PLAINS. BEST CHANCES FOR PRECIP ARE BETWEEN 12
AND 15 UTC AT THE EASTERN TAF SITES MINUS KMSN. KMSN SHOULD SEE
SHOWERS EARLIER WITH THEIR BEST CHANCE AFTER 9 UTC. A BIT UNCERTAIN
GIVEN THE SHOWERY NATURE THAT IS EXPECTED...SO HAVE VCSH STARTING A
LITTLE EARLIER. CEILINGS OF 5000 FT ARE EXPECTED WITH THE SHOWERS
WITH VIS GREATER THAN OR EQUAL TO 6 SM.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 7 PM FRIDAY
EVENING TO 3 PM SATURDAY NORTH OF PORT WASHINGTON TO SHEBOYGAN.
WINDS OVER THE NEARSHORE WATERS WILL BE BREEZY THIS EVENING AND
OVERNIGHT AND WILL BUILD WAVES 3 TO 5 FT NORTH OF PORT WASHINGTON.
ELSEWHERE...WAVES WILL BE BETWEEN 2 AND 3 FT. THE WAVES AND WINDS
WILL SUBSIDE AFTER A COLD FRONT PASSES THROUGH SATURDAY AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT SATURDAY FOR LMZ643.
&&
$$
UPDATE...REM
TONIGHT/SATURDAY AND AVIATION/MARINE...ET
SATURDAY NIGHT THROUGH FRIDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
910 PM CDT FRI OCT 11 2013
.UPDATE...TONIGHT INTO TOMORROW
ISSUED AT 910 PM CDT FRI OCT 11 2013
CHANGES ARE ON THE WAY AS A COLD FRONT WILL COME THROUGH THE
REGION TONIGHT. A FIRST ROUND OF ISOLATED TO SCATTERED SHOWERS HAS
MOVED INTO NW WI/SE MN/NE IA ALONG A WEAKENING LEAD MID LEVEL
TROUGH. FURTHER TO THE WEST...A NARROW BAND OF SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ALONG A STRONG FRONTOGENETIC BAND
ALONG THE SURFACE COLD FRONT. INSTABILITY IS RATHER LIMITED WITH
12.01Z LAPS ANALYSIS SHOWING ABOUT 500 J/KG OF MUCAPE ACROSS SOUTH
CENTRAL MINNESOTA. RECENT MESO MODELS SEEM TO HAVE A DECENT IDEA
OF SHOWING THE LATEST DEVELOPMENT ALONG THE COLD FRONT WITH A
GRADUAL WEAKENING OF THE INSTABILITY/FGEN ALONG/AHEAD OF THE FRONT
OVERNIGHT. LOW LEVEL TO DEEP WIND SHEAR IS MORE THAN SUPPORTIVE OF
SEVERE WEATHER...BUT THE LACK OF INSTABILITY AND DEEP FORCING
ABOVE THE SURFACE/LOW LEVELS WILL KEEP THIS CONVECTION LOW TOPPED
AND NOT SEVERE.
ONCE THE FRONT MOVES THROUGH...WINDS WILL SHIFT TO THE WEST AND
REMAIN GUSTY ON INTO THE AFTERNOON SATURDAY. HAVE BUMPED UP THE
GUSTS THERE BUT IT DOES NOT LOOK HIGH ENOUGH TO WARRANT AN
ADVISORY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
AT 3 PM...A 990 MB SURFACE LOW WAS LOCATED JUST NORTH OF PIERRE
SOUTH DAKOTA. DURING THE PAST 3 HOURS...MSAS DATA SHOWS THAT THE
SURFACE PRESSURE HAS FALLEN 4 MB ACROSS NORTHEAST SOUTH DAKOTA.
MEANWHILE THE PRESSURE HAS RISEN 6 MB ACROSS THE NEBRASKA
PANHANDLE. LAPS SHOWS THE TROPOSPHERIC FOLD EXTENDING DOWN
800 MB. MEANWHILE FURTHER SOUTHEAST...THERE IS A 1019 MB SURFACE
HIGH CENTERED OVER KENTUCKY. THE TIGHT SURFACE PRESSURE GRADIENT
BETWEEN THESE TWO SYSTEMS HAS RESULTED IN WIND GUSTS AS HIGH AS
41 MPH /149 PM/ AT ROCHESTER INTERNATIONAL AIRPORT AND 39 MPH
/133 PM/ AT THE DODGE CENTER AWOS. A BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUES TO BE LOCATED ACROSS NORTH-CENTRAL IOWA
AND SOUTH-CENTRAL MINNESOTA. THIS IS LOCATED IN AN AREA OF DEEP
MOISTURE CONVERGENCE.
FOR TONIGHT...THE LATEST RAP SHOW THAT THE 850 MB MOISTURE
TRANSPORT WILL GRADUALLY WEAKEN AND SHIFT NORTHEAST INTO NORTHERN
WISCONSIN THIS EVENING. IN ADDITION...THE 900 TO 800 MB
FRONTOGENESIS WILL GRADUALLY WEAKEN AS IT MOVES EAST ACROSS THE
FORECAST AREA. THIS WILL RESULT IN THE ECHO COVERAGE BECOMING MORE
SCATTERED. THIS SHOWS UP WELL IN THE RAP...NMM...AND ARW. AS A
RESULT...KEPT THE PRECIPITATION CHANCES IN THE 15 TO 24 PERCENT
RANGE. ML CAPES GRADUALLY DECREASE FROM AROUND 500 J/KG LATE THIS
AFTERNOON TO LESS THAN 200 J/KG AFTER MIDNIGHT. DUE TO
THIS...CONFINED THE ISOLATED THUNDERSTORMS TO THE EVENING. LIKE
YESTERDAY...IT APPEARS THAT THE SHEAR WILL BE TOO GREAT FOR THE
AMOUNT OF INSTABILITY AVAILABLE...THUS ANY THUNDERSTORMS THAT DO
HAPPEN DEVELOP WILL LIKELY GET SHEARED APART QUICKLY. WITH LOSS OF
DIURNAL HEATING LATE THIS AFTERNOON AND EARLY EVENING...EXPECT THE
WIND GUSTS TO QUICKLY WANE.
ON SATURDAY MORNING...THE 11.12Z MODELS APPEAR TO BE JUST A BIT
SLOWER AT MOVING THE FRONT OUT OF THE AREA. AS A RESULT...HELD
ONTO A SLIGHT CHANCE OF SHOWERS IN CENTRAL AND SOUTHWEST WISCONSIN
THROUGH 12.14Z.
ON SATURDAY EVENING...ANOTHER SHORT WAVE TROUGH MOVES EAST THROUGH
THE REGION. LIKE YESTERDAY...THE BEST SYNOPTIC FORCING AND
MOISTURE LOOKS TO BE WELL NORTH OF THE FORECAST AREA. AS A
RESULT...KEPT THE FORECAST DRY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
ON SATURDAY NIGHT...A CANADIAN HIGH WILL BUILD ACROSS THE AREA.
WITH THE CENTER OF THIS HIGH BEING LOCATED MORE ACROSS IOWA THAN
OUR FORECAST AREA. THINKING THAT THERE MIGHT BE JUST ENOUGH MIXING
IN THE BOUNDARY LAYER TO PREVENT THE TEMPERATURES BOTTOMING OUT AS
MUCH AS THEY WILL BE UNDERNEATH THE CORE OF THE HIGH. AS A RESULT...
KEPT LOW TEMPERATURES IN THE 35 TO 42 DEGREE RANGE. THE WARMEST
TEMPERATURES WILL BE FOUND IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS. MEANWHILE THE REMAINDER OF THE AREA WILL BE COLD ENOUGH
FOR SOME FROST TO DEVELOP.
ON SUNDAY NIGHT...THE COMBINATION OF LIGHT WINDS AND MOSTLY CLEAR
SKIES ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN WILL ALLOW
TEMPERATURES TO FALL INTO THE MID 30S. THESE TEMPERATURES WILL BE
COLD ENOUGH FOR SOME FROST TO DEVELOP.
FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO
LOW THAT A CLOSED 500 MB LOW WILL MOVE THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY. THE MAIN QUESTION IS WHEN EXACTLY WILL
THIS OCCUR. THE 11.12Z ECMWF IS A BIT SLOWER THAN ITS PREVIOUS RUN
AND SLOWER THAN SOME OF THE OTHER DETERMINISTIC MODELS. AS
RESULT NOT EXACTLY SURE WHICH TIME PERIOD /MONDAY NIGHT...TUESDAY...
OR BOTH/ TO GO WITH CATEGORICAL PRECIPITATION CHANCES /80 TO
100 PERCENT/. WITH THIS UNCERTAINTY...JUST STAYED WITH THE ALL
BLEND SOLUTION. A COUPLE OF DAYS AGO...IT LOOKED LIKE WE WOULD
POTENTIALLY SEE SOME THUNDERSTORMS AHEAD OF THIS LOW...BUT THE
MODELS NOW SUGGEST THAT WE WILL ONLY SEE RAIN FROM THIS SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 636 PM CDT FRI OCT 11 2013
INITIAL FOCUS OF THE FORECAST IS ON THE INITIAL BAND OF RAIN
SHOWERS CURRENTLY MOVING EAST ACROSS SOUTHEAST MINNESOTA.
CONDITIONS ARE VFR FOR THE MOST PART THOUGH VIS HAS BRIEFLY
DROPPED TO 4-5SM IN A FEW SPOTS THAT MANAGED TO GET HIT WITH SOME
OF THE STRONGER SHOWERS. CHANCES ARE LOW ENOUGH FOR THESE MVFR
CONDITIONS THAT THEY HAVE BEEN LEFT FROM THE TAFS. EXPECT THAT
THESE SHOWERS WILL BE CLEAR OF RST AROUND 1Z AND INTO LSE BETWEEN
2-5Z. AFTER THAT...THE COLD FRONT WILL COME THROUGH OVERNIGHT AS
MAINLY A WIND SHIFT WITH LITTLE IN THE WAY OF SHOWERS DEVELOPING
ALONG IT. WITH COOLER AND DRIER AIR MOVING INTO THE REGION...SOME
DEEP MIXING WILL OCCUR IN THE LATE MORNING/AFTERNOON HOURS ON
SATURDAY WITH SOME GUSTS IN THE 25-30KT RANGE EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
636 PM CDT FRI OCT 11 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
AT 3 PM...A 990 MB SURFACE LOW WAS LOCATED JUST NORTH OF PIERRE
SOUTH DAKOTA. DURING THE PAST 3 HOURS...MSAS DATA SHOWS THAT THE
SURFACE PRESSURE HAS FALLEN 4 MB ACROSS NORTHEAST SOUTH DAKOTA.
MEANWHILE THE PRESSURE HAS RISEN 6 MB ACROSS THE NEBRASKA
PANHANDLE. LAPS SHOWS THE TROPOSPHERIC FOLD EXTENDING DOWN
800 MB. MEANWHILE FURTHER SOUTHEAST...THERE IS A 1019 MB SURFACE
HIGH CENTERED OVER KENTUCKY. THE TIGHT SURFACE PRESSURE GRADIENT
BETWEEN THESE TWO SYSTEMS HAS RESULTED IN WIND GUSTS AS HIGH AS
41 MPH /149 PM/ AT ROCHESTER INTERNATIONAL AIRPORT AND 39 MPH
/133 PM/ AT THE DODGE CENTER AWOS. A BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUES TO BE LOCATED ACROSS NORTH-CENTRAL IOWA
AND SOUTH-CENTRAL MINNESOTA. THIS IS LOCATED IN AN AREA OF DEEP
MOISTURE CONVERGENCE.
FOR TONIGHT...THE LATEST RAP SHOW THAT THE 850 MB MOISTURE
TRANSPORT WILL GRADUALLY WEAKEN AND SHIFT NORTHEAST INTO NORTHERN
WISCONSIN THIS EVENING. IN ADDITION...THE 900 TO 800 MB
FRONTOGENESIS WILL GRADUALLY WEAKEN AS IT MOVES EAST ACROSS THE
FORECAST AREA. THIS WILL RESULT IN THE ECHO COVERAGE BECOMING MORE
SCATTERED. THIS SHOWS UP WELL IN THE RAP...NMM...AND ARW. AS A
RESULT...KEPT THE PRECIPITATION CHANCES IN THE 15 TO 24 PERCENT
RANGE. ML CAPES GRADUALLY DECREASE FROM AROUND 500 J/KG LATE THIS
AFTERNOON TO LESS THAN 200 J/KG AFTER MIDNIGHT. DUE TO
THIS...CONFINED THE ISOLATED THUNDERSTORMS TO THE EVENING. LIKE
YESTERDAY...IT APPEARS THAT THE SHEAR WILL BE TOO GREAT FOR THE
AMOUNT OF INSTABILITY AVAILABLE...THUS ANY THUNDERSTORMS THAT DO
HAPPEN DEVELOP WILL LIKELY GET SHEARED APART QUICKLY. WITH LOSS OF
DIURNAL HEATING LATE THIS AFTERNOON AND EARLY EVENING...EXPECT THE
WIND GUSTS TO QUICKLY WANE.
ON SATURDAY MORNING...THE 11.12Z MODELS APPEAR TO BE JUST A BIT
SLOWER AT MOVING THE FRONT OUT OF THE AREA. AS A RESULT...HELD
ONTO A SLIGHT CHANCE OF SHOWERS IN CENTRAL AND SOUTHWEST WISCONSIN
THROUGH 12.14Z.
ON SATURDAY EVENING...ANOTHER SHORT WAVE TROUGH MOVES EAST THROUGH
THE REGION. LIKE YESTERDAY...THE BEST SYNOPTIC FORCING AND
MOISTURE LOOKS TO BE WELL NORTH OF THE FORECAST AREA. AS A
RESULT...KEPT THE FORECAST DRY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
ON SATURDAY NIGHT...A CANADIAN HIGH WILL BUILD ACROSS THE AREA.
WITH THE CENTER OF THIS HIGH BEING LOCATED MORE ACROSS IOWA THAN
OUR FORECAST AREA. THINKING THAT THERE MIGHT BE JUST ENOUGH MIXING
IN THE BOUNDARY LAYER TO PREVENT THE TEMPERATURES BOTTOMING OUT AS
MUCH AS THEY WILL BE UNDERNEATH THE CORE OF THE HIGH. AS A RESULT...
KEPT LOW TEMPERATURES IN THE 35 TO 42 DEGREE RANGE. THE WARMEST
TEMPERATURES WILL BE FOUND IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS. MEANWHILE THE REMAINDER OF THE AREA WILL BE COLD ENOUGH
FOR SOME FROST TO DEVELOP.
ON SUNDAY NIGHT...THE COMBINATION OF LIGHT WINDS AND MOSTLY CLEAR
SKIES ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN WILL ALLOW
TEMPERATURES TO FALL INTO THE MID 30S. THESE TEMPERATURES WILL BE
COLD ENOUGH FOR SOME FROST TO DEVELOP.
FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO
LOW THAT A CLOSED 500 MB LOW WILL MOVE THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY. THE MAIN QUESTION IS WHEN EXACTLY WILL
THIS OCCUR. THE 11.12Z ECMWF IS A BIT SLOWER THAN ITS PREVIOUS RUN
AND SLOWER THAN SOME OF THE OTHER DETERMINISTIC MODELS. AS
RESULT NOT EXACTLY SURE WHICH TIME PERIOD /MONDAY NIGHT...TUESDAY...
OR BOTH/ TO GO WITH CATEGORICAL PRECIPITATION CHANCES /80 TO
100 PERCENT/. WITH THIS UNCERTAINTY...JUST STAYED WITH THE ALL
BLEND SOLUTION. A COUPLE OF DAYS AGO...IT LOOKED LIKE WE WOULD
POTENTIALLY SEE SOME THUNDERSTORMS AHEAD OF THIS LOW...BUT THE
MODELS NOW SUGGEST THAT WE WILL ONLY SEE RAIN FROM THIS SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 636 PM CDT FRI OCT 11 2013
INITIAL FOCUS OF THE FORECAST IS ON THE INITIAL BAND OF RAIN
SHOWERS CURRENTLY MOVING EAST ACROSS SOUTHEAST MINNESOTA.
CONDITIONS ARE VFR FOR THE MOST PART THOUGH VIS HAS BRIEFLY
DROPPED TO 4-5SM IN A FEW SPOTS THAT MANAGED TO GET HIT WITH SOME
OF THE STRONGER SHOWERS. CHANCES ARE LOW ENOUGH FOR THESE MVFR
CONDITIONS THAT THEY HAVE BEEN LEFT FROM THE TAFS. EXPECT THAT
THESE SHOWERS WILL BE CLEAR OF RST AROUND 1Z AND INTO LSE BETWEEN
2-5Z. AFTER THAT...THE COLD FRONT WILL COME THROUGH OVERNIGHT AS
MAINLY A WIND SHIFT WITH LITTLE IN THE WAY OF SHOWERS DEVELOPING
ALONG IT. WITH COOLER AND DRIER AIR MOVING INTO THE REGION...SOME
DEEP MIXING WILL OCCUR IN THE LATE MORNING/AFTERNOON HOURS ON
SATURDAY WITH SOME GUSTS IN THE 25-30KT RANGE EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
320 PM CDT THU OCT 10 2013
.VERY SHORT TERM...TONIGHT AND FRIDAY.
PATTERN REMAINS ESSENTIALLY UNCHANGED WITH JUST A SLOW APPROACH OF
THE TROUGH FROM THE PLAINS. DEW POINTS INCREASING INTO THE 50S
ACROSS ILLINOIS AND THIS MOISTURE WILL CONTINUE TO BE DRAWN NORTH.
LOW LEVEL RH PROGS HAVE BEEN CONSISTENT IN SHOWING THIS INCREASE IN
RH ADVECTING INTO OUR AREA LATER TONIGHT INTO FRIDAY. MAIN CONCERN
RESTS WITH HOW EXTENSIVE FOG WILL BE. SREF...WHILE WOEFULLY
UNDERFORECASTING FOG LAST NIGHT...IS SHOWING A LITTLE BETTER SIGNAL
TONIGHT. HRRR SHOWS SOME FOG MOVING IN FROM THE LAKE AS THE NIGHT
WEARS ON. THE 925-950 WINDS ARE A BIT HIGHER THAN LAST NIGHT.
OVERALL THE GRADIENT IN THE CWA REMAINS PRETTY WEAK. FOR NOW WILL
STICK WITH THE PATCHY FOG IDEA...THOUGH FEEL THE EASTERN CWA MAY BE
MORE FAVORED FOR A BIT MORE GIVEN LESS 925/850 WIND SPEEDS AND
PROXIMITY TO THE LAKE. WILL PASS ALONG CONCERNS TO THE EVENING SHIFT.
WARM AND MILD DAY AFTER THE LINGERING FOG BURNS OFF. 925 TEMPS
MODIFY FURTHER INTO THE 15-17C RANGE. THE 925-850 RH SUGGESTS WE MAY
END UP WITH AT LEAST A BROKEN CU FIELD WITH THE HIGHER DEW POINTS IN
PLACE. ANY FORCING FROM THE SURFACE FRONT OR UPPER TROUGH WILL
REMAIN TO OUR WEST. WITH THE PRESSURE GRADIENT TIGHTENING
UP...BREEZY SSE WINDS ARE EXPECTED WITH 925 WINDS INCREASING TO 20
TO 30 KNOTS IN THE AFTERNOON.
.SHORT TERM...FRIDAY NIGHT THROUGH SUNDAY.
SHORT TERM GUIDANCE IN GOOD AGREEMENT ON CARRYING COLD FRONT ACROSS
SOUTHERN WISCONSIN LATER FRIDAY NIGHT AND SATURDAY MORNING. COLUMN
PRECIPITABLE WATER INCREASES TO OVER ONE INCH AHEAD OF THE FRONT
FRIDAY EVENING. WHILE MAIN SHORT WAVE TROUGH REMAINS WELL WEST OF
THE AREA...SPOKE OF SHORT WAVE VORTICITY AND WEAKER WARM AIR
ADVECTION SWEEP ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY MORNING.
MUCAPE INCREASES TO AROUND 200 J/KG. BEST CHANCE FOR SHRA WL BE
SATURDAY MORNING ACROSS ERN CWA WHEN LOW LEVEL FORCING ASSOCD WITH
FRONT COINCIDES WITH RIGHT ENTRANCE REGION OF PASSING UPPER JET.
DRIER AIR SETTLES IN FAIRLY QUICKLY BEHIND FRONT ON SATURDAY AS MAIN
SHORT WAVE TROUGH SWEEPS ACROSS WISCONSIN.
SFC HIGH PRESSURE SETTLES IN SATURDAY NIGHT. CLEAR SKIES AND 925H
TEMPS FAVOR OVERNIGHT LOWS DIPPING INTO THE UPPER 30S TO LOW 40S.
FOR NOW WILL HOLD OFF ON MENTIONING FROST IN WESTERN CWA DUE TO
BOUNDARY LAYER MIXING BUT WL NEED TO WATCH THOSE OVERNIGHT TEMPS
CLOSELY FOR SUNDAY MORNING.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY.
SHORT WAVE RIDGING AND DRY EASTERLY FLOW WILL RESULT IN A PLEASANT
START TO THE EXTENDED PERIOD...WITH DRY CONDITIONS EXPECTED SUNDAY
NIGHT AND MONDAY. INCREASING SOUTHERLY WINDS AHEAD OF AN
APPROACHING SHORT WAVE TROUGH WILL BEGIN TO CARRY DEEPER MOISTURE
INTO THE AREA MONDAY NIGHT. EXTENDED GUIDANCE IS IN REASONABLE
AGREEMENT ON SHORT WAVE TROUGH AND SURFACE SYSTEM AFFECTING SOUTHERN
WI MONDAY NIGHT THROUGH MID-WEEK...HOWEVER CONSIDERABLE DIFFERENCES
ON STRENGTH OF SYSTEM AS WELL AS TIMING. AT THIS POINT...WL LEAN
MORE ON WEAKER SOLUTION THAT GEM AND ECMWF HAVE BEEN GRAVITATING
TOWARDS OVER LAST SEVERAL RUNS...CONSIDERING LACK OF UPSTREAM KICKER
AND INCREASE OF SIGNIFICANT BAROCLINICITY...AND DISREGARD GFS
STRONGER SOLUTION AS MORE OF AN OUTLIER FOR NOW. HENCE SHOWER
THREAT SPREADS INTO THE AREA LATER MONDAY NIGHT AND CONTINUES INTO
WED.
MAY BE A BRIEF PERIOD OF DRY WEATHER AROUND WED NGT...HOWEVER WITH
LINGERING UPSTREAM TROF...ANOTHER SHORT WAVE LOOKS TO AFFECT THE
AREA ON THURSDAY. THIS SECOND SYSTEM WILL LIKELY USHER COLDER AIR
INTO THE AREA WITH AN INCREASING LIKLIHOOD OF FROST/FREEZING TEMPS
TOWARD THE END OF NEXT WEEK. GFS 5-DAY 500H MEANS SHOW 150 METER
NEGATIVE ANOMOLY SETTING UP OVER THE WESTERN GREAT LAKES CENTERED AT
00Z/18.
&&
.AVIATION /00Z TAFS/...MAIN CONCERN WILL BE FOG REDEVELOPMENT
TONIGHT INTO FRIDAY MORNING. 925-850 WINDS WILL BE STRONGER THAN
LAST NIGHT THOUGH SURFACE WINDS WILL BE FAIRLY WEAK FROM THE
SOUTHEAST. MOS AND HRRR VSBYS HANDLED THINGS PRETTY WELL LAST NIGHT
WITH SREF NOT SO GOOD. WILL TREND VSBYS LOWER GIVEN CONSENSUS
BETWEEN GFS AND NAM MOS DATA. HIGHER 925-850 RH FIELD SURGES NORTH
LATER TONIGHT INTO FRIDAY. THIS CURRENTLY SHOWING ITSELF AS A
DIURNALLY DRIVEN CU FIELD CNTRL IL. SO AT THIS TIME WILL NOT
FORECAST WIDESPREAD STRATUS WITH THIS INCREASE IN RH. MAIN DYNAMICS
AND FRONTAL FORCING FOR SHRA/TSRA ARRIVE FRIDAY NIGHT INTO SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
.CONFIDENCE...
TONIGHT AND FRIDAY...MEDIUM.
FRIDAY NIGHT AND SATURDAY...MEDIUM.
SATURDAY NIGHT AND SUNDAY...MEDIUM TO HIGH.
SUNDAY NIGHT AND MONDAY...HIGH.
MONDAY NIGHT THROUGH THURSDAY...MEDIUM.
$$
VERY SHORT TERM/AVIATION...PC
SHORT TERM/LONG TERM...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1228 PM CDT THU OCT 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 225 AM CDT THU OCT 10 2013
NO FORECAST CONCERNS FOR THE SHORT TERM PERIOD WITH QUIET WEATHER
CONTINUING.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A NORTHERN STREAM UPPER TROUGH CROSSING BRITISH COLUMBIA...A
DEEP UPPER LOW/TROUGH OVER SOUTHERN CALIFORNIA...AND STRONG RIDGING
FROM EASTERN TEXAS THROUGH THE EASTERN GREAT LAKES. VERY LITTLE
CLOUD COVER TO SPEAK OF FROM THE CENTRAL PLAINS INTO THE FORECAST
AREA... EXCEPT FOR A BAND OF CIRRUS ASSOCIATED WITH A SHORTWAVE
LIFTING THROUGH WESTERN IA. THE LACK OF CLOUD COVER IS A RESULT OF
PLENTIFUL DRY AIR SEEN ON 00Z SOUNDINGS FROM GRB...DVN...MPX...OAX
AND DDC. AT THE SURFACE...LOW PRESSURE WAS DEVELOPING OVER EASTERN
COLORADO WHILE HIGH PRESSURE WAS PRESENT OVER LOWER MICHIGAN. THE
PRESSURE GRADIENT BETWEEN THESE FEATURES OVER THE FORECAST AREA IS
LIGHTER THAN THIS TIME YESTERDAY...RESULTING IN LIGHTER WINDS AND
THEREFORE COOLER TEMPERATURES. THE TYPICAL WISCONSIN COLD SPOTS HAVE
DROPPED INTO THE UPPER 30S...MEANWHILE HIGHER TERRAIN SITES ALONG
AND WEST OF THE MISSISSIPPI RIVER WHICH ARE EXPERIENCING MORE WIND
ARE IN THE LOW TO MID 50S. AIRMASS REMAINS ABNORMALLY WARM...
THOUGH...WITH 00Z SOUNDINGS SHOWING 925MB TEMPERATURES OF 15-17C
EAST TO WEST.
THE DRY CONDITIONS WILL CONTINUE FOR ANOTHER 24 HOURS AS THE
FORECAST AREA REMAINS SITUATED IN A BLOCKED UPPER LEVEL PATTERN.
THAT PATTERN FEATURES THE UPPER LOW IN SOUTHERN CALIFORNIA PROGGED
TO EJECT NORTHEASTWARD TOWARDS THE BLACK HILLS OF SOUTH DAKOTA BY
12Z FRIDAY...WHILE STRONG RIDGING HOLDS IN PLACE OVER LOWER
MICHIGAN. EXPECT WINDS TO INCREASE...A RESULT OF THE PRESSURE
GRADIENT TIGHTENING AHEAD OF THE DEEPENING SURFACE LOW IN COLORADO
LIFTING NORTH WITH THE UPPER LOW. THE STRONGER SOUTHERLY WINDS DO
NOT BRING ANY WARMER AIR IN FOR TODAY AT 925MB...AS MODEL FORECASTS
SUGGESTS 925MB TEMPERATURES END UP AGAIN BETWEEN 16-18C AT 00Z. THUS
HIGHS ARE LIKELY TO BE SIMILAR TO THOSE SEEN YESTERDAY. HOWEVER...
THE WINDS WILL HELP TO KEEP THE NEAR SURFACE LAYER MORE MIXED
TONIGHT...RESULTING IN A WARMER NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 225 AM CDT THU OCT 10 2013
FORECAST CONCERNS ARE ON WINDS FRIDAY...PRECIPITATION CHANCES LATE
FRIDAY THROUGH SATURDAY...AND PRECIPITATION CHANCES AGAIN EARLY NEXT
WEEK.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT THAT THE UPPER AND SURFACE LOWS OVER
WESTERN SOUTH DAKOTA FRIDAY MORNING WILL CONTINUE LIFTING
NORTH-NORTHEAST...AND BEGIN PHASING FRIDAY NIGHT WITH THE NORTHERN
STREAM TROUGH CURRENTLY OVER BRITISH MARCHING EAST. AS THIS PHASING
OCCURS...THE SYSTEMS COLD FRONT LOOKS PROGGED TO MOVE THROUGH THE
FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY. ANOTHER SHORTWAVE
TROUGH LOOKS TO MOVE INTO THE AREA LATE SATURDAY BUT LITTLE IMPACT
IS SUGGESTED WITH IT. ATTENTION THEN FOCUSES BACK WEST AS ANOTHER
DEEP UPPER TROUGH IS PROGGED TO DEVELOP OVER THE WESTERN U.S..
ECMWF/GFS/CANADIAN AND THEIR RESPECTIVE ENSEMBLES ARE COMING INTO
BETTER AGREEMENT OF THIS UPPER TROUGH EJECTING EASTWARD SLOWLY
TOWARDS THE FORECAST AREA MONDAY NIGHT THROUGH WEDNESDAY. A
RELATIVELY STRONG SURFACE SYSTEM LOOKS TO ACCOMPANY THIS
TROUGH...SETTING UP A GOOD CHANCE OF RAIN DURING THIS
PERIOD...ESPECIALLY MONDAY NIGHT AND TUESDAY.
DETAILS...
WINDS ON FRIDAY REMAIN IN FOCUS AS A TIGHT PRESSURE GRADIENT IS
FORECAST OVER THE AREA AHEAD OF THE DAKOTAS LOW. THE BEST
JUXTAPOSITION OF HIGHEST PRESSURE GRADIENT MAGNITUDE AND MIXING
APPEARS TO OCCUR OVER SOUTHEAST MN. MOMENTUM TRANSFER FROM SOUNDINGS
SUGGEST GUSTS OVER THE HIGHER TERRAIN OF SOUTHEAST MN OF 35 KT...AND
PERHAPS BRIEFLY UP TO 40 KT. THUS...THE CONCERN FOR A MARGINAL WIND
ADVISORY PERSISTS. ELSEWHERE...GUSTS OF 25-30 KT SEEM REASONABLE.
THESE WINDS OUT OF THE SOUTH HELP TO ADVECT IN 925MB TEMPS OF
16-18C...ALLOWING HIGH TEMPERATURES TO END UP SLIGHTLY WARMER THAN
TODAY.
NEXT CONCERN IS ON PRECIPITATION CHANCES. A WARM CONVEYOR BELT OF
PRECIPITATION AHEAD OF THE LOW SHOULD BE LIFTING THROUGH WESTERN
PORTIONS OF IOWA AND MINNESOTA FRIDAY MORNING. ALL INDICATIONS...
MINUS THE 10.00Z ECMWF...ARE THAT THIS BELT OF PRECIPITATION WILL
FALL APART AS IT PUSHES TOWARDS THE FORECAST AREA FRIDAY
AFTERNOON...RESULTING FROM RUNNING INTO DRIER AIR AND THE DYNAMIC
FORCING LIFTING NORTH. THE ECMWF HOLDS PRECIPITATION TOGETHER TO
AFFECT SOUTHEAST MN AND NORTHEAST IA. FOR NOW HAVE KEPT FRIDAY
MOSTLY DRY FROM THE PREVIOUS FORECAST...BUT INTRODUCED A SPRINKLES
MENTION. AN INCREASE IN CLOUDS IS LIKELY LATER IN THE DAY NO MATTER
WHAT. THERE IS GOOD MODEL AGREEMENT FRIDAY NIGHT AND ESPECIALLY ON
SATURDAY THAT A BAND OF SHOWERS WILL FORM AROUND THE COLD FRONT
MARCHING EAST. THIS PRECIPITATION IS A RESULT OF MID LEVEL
FRONTOGENESIS FORCING AND A STREAM OF 1-1.3 INCH PRECIPITABLE WATER
VALUES ADVECTING NORTH PROVIDING MOISTURE. THE FORECAST PROBLEM IS
WHERE THE PRECIPITATION ENDS UP AS MODELS DIFFER ON FRONTAL TIMING.
TIMING OF THE FRONT TO GET THROUGH THE ENTIRE AREA VARIES FROM 12Z
SATURDAY ACCORDING TO THE 10.00Z NAM...15Z SATURDAY FROM THE 10.00Z
GFS...18Z SATURDAY FROM THE 10.00Z CANADIAN/ECMWF AND ABOUT 21Z
SATURDAY FROM THE 10.00Z UKMET/09.12Z ECMWF. IF THE FRONT ENDS UP
SLOWER...THE GREATER THE CHANCE AT LEAST THE SOUTHEAST HALF OF THE
FORECAST AREA WILL SEE RAIN. FOR NOW...HAVE STAYED WITH A CONSENSUS
APPROACH WHICH RESULTS IN MAXIMUM CHANCES IN THE 30-35 PERCENT
RANGE.
TEMPERATURES DEFINITELY LOOK COOLER FOR THE WEEKEND AS 925MB
READINGS FALL TO 10-13C ON SATURDAY AND 8-10C ON SUNDAY.
DRY CONDITIONS ARE LIKELY SATURDAY NIGHT THROUGH AT LEAST MONDAY
MORNING AS THE AREA IS UNDER THE INFLUENCE OF HIGH PRESSURE.
ATTENTION THEN TURNS TO THE UPPER TROUGH AND LOW PRESSURE SYSTEM
COMING OUT OF THE WESTERN U.S. AND PLAINS. PRECIPITABLE WATER VALUES
AGAIN CLIMB TO 1-1.3 INCHES OR UP TO 200 PERCENT OF NORMAL AHEAD OF
THE SYSTEM. THE COMBINATION OF THIS MOISTURE...FRONTOGENETICAL AND
DPVA FORCING WILL ALL COMBINE TO SPREAD PRECIPITATION ACROSS THE
UPPER MIDWEST WITH THIS SYSTEM. MODEL TIMING OF THIS PRECIPITATION
TO AFFECT THE FORECAST AREA IS REALLY CENTERING ON MONDAY NIGHT AND
TUESDAY...THUS HAVE RAISED PRECIPITATION CHANCES CONSIDERABLY FOR
THIS TIME PERIOD. MUCAPE IS ALMOST NIL WITH THE SYSTEM...RESULTING
FROM NEARLY MOIST-ADIABATIC LAPSE RATES...THUS HAVE KEPT THE MENTION
OF THUNDER OUT OF THE FORECAST. THE FORECAST AREA LOOKS TO BECOME
AFFECTED BY THE COLD CONVEYOR BELT OF THE SYSTEM TUESDAY NIGHT AND
WEDNESDAY...RESULTING IN THE NEED TO CARRY 30-50 PERCENT CHANCES.
THESE MAY NEED TO BE RAISED LATER AS THE SYSTEM TRACK FIRMS UP.
THERMAL FIELDS ARE WARM ENOUGH TO KEEP THE PRECIPITATION TYPE AS
RAIN...BUT WITH 925MB TEMPS DROPPING TO 3-6C ON WEDNESDAY...IT IS
GOING TO FEEL MUCH COLDER THAN WHAT WE HAVE SEEN AS OF LATE.
&&
.AVIATION...THROUGH 18Z FRIDAY
1228 PM CDT THU OCT 10 2013
MAIN AVIATION CONCERNS ARE WIND SPEEDS AND GUSTS AT BOTH RST AND
LSE TAF SITES AFTER 12Z FRIDAY. VFR CONDITIONS WILL CONTINUE TO PREVAIL
THROUGH THE TAF PERIOD. PRESSURE GRADIENT WILL BE MORE RELAXED
ACROSS THE REGION THIS AFTERNOON THAN PREVIOUS COUPLE OF
DAYS...SOUTHERLY WIND SPEEDS WILL BE IN THE 10 TO 12 KNOT RANGE AT
BOTH TAF SITES WITH GUSTS POSSIBLY UP TO 20 KNOTS AT RST THIS
AFTERNOON. WINDS WILL DIMINISH THIS EVENING. THEN...PRESSURE
GRADIENT TIGHTENS ACROSS THE AREA AFTER 12Z FRIDAY...AS LOW
PRESSURE DEEPENS OVER THE DAKOTAS. THIS WILL ALLOW WINDS TO INCREASE
TO 15 TO 20 KNOTS WITH GUST 25 TO 30 KNOTS AT BOTH TAF SITES AFTER
12Z FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1127 AM CDT THU OCT 10 2013
.AVIATION/18Z TAFS/...MAIN CONCERN WILL BE FOG REDEVELOPMENT
TONIGHT INTO FRIDAY MORNING. 925-850 WINDS WILL BE STRONGER THAN
LAST NIGHT THOUGH SURFACE WINDS WILL BE FAIRLY WEAK FROM THE SOUTHEAST.
MOS AND HRRR VSBYS HANDLED THINGS PRETTY WELL LAST NIGHT WITH SREF
NOT SO GOOD. WILL TREND VSBYS LOWER THAN CURRENT FCST GIVEN
CONSENSUS BETWEEN GFS AND NAM MOS DATA. HIGHER 925-850 RH FIELD
SURGES NORTH LATER TONIGHT INTO FRIDAY. THIS CURRENTLY SHOWING
ITSELF AS A DIURNALLY DRIVEN CU FIELD CNTRL IL. SO AT THIS TIME
WILL NOT FORECAST WIDESPREAD STRATUS WITH THIS INCREASE IN RH.
SYNOPTICALLY INDUCED CLOUD FIELD WITH APPROACHING TROUGH PROGGD TO
REMAIN WEST OF THE AREA THROUGH LATE FRIDAY.
PC
&&
.PREV DISCUSSION... /ISSUED 327 AM CDT THU OCT 10 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.
PATCHY GROUND FOG WILL PREVAIL EARLY THIS MORNING ESPECIALLY IN
THE FAVORED AREAS. OTHERWISE SELY FLOW WILL CONTINUE TODAY AND TNT
AS HIGH PRESSURE REMAINS OVER THE ERN GREAT LAKES AND CYCLOGENESIS
ENSUES FROM NE CO AND TRACKS TO THE SD/NE BORDER BY 12Z FRI. THIS
IS IN RESPONSE TO THE UPPER LOW OVER SRN CA THAT WILL LIFT NEWD TO
THE SD/NE BORDER BY 12Z FRI.
925 MB TEMPS IN THE MID TEENS CELSIUS SUGGESTS HIGH TEMPS WILL BE
IN THE LOWER 70S INLAND. THE LAKE BREEZE AND SYNOPTIC SELY FLOW
WILL DEVELOP EARLIER TODAY THAN YESTERDAY SO EXPECT TEMPS TO BE A
LITTLE COOLER OVER THE LAKE COUNTIES.
FOR TNT THE SLY FLOW WILL BRING INCREASED AMOUNTS OF LOW LEVEL
MOISTURE INTO THE REGION. THIS SHOULD RESULT IN SCT CLOUD COVER
AFTER 08Z ALONG WITH PATCHY FOG.
FRIDAY THROUGH SATURDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM TO
HIGH.
SHORT TERM MODELS IN GOOD AGREEMENT WITH FEATURES DURING THIS
PERIOD. DEEP LOW PRESSURE AND ASSOCIATED 500MB LOW WILL SHIFT FROM
CENTRAL SOUTH DAKOTA TO EASTERN MANITOBA CANADA FRIDAY AND FRIDAY
NIGHT. BREEZY SOUTH SOUTHEAST WINDS WILL KEEP WARM TEMPERATURES
ACROSS THE AREA FRIDAY...WITH DRY CONDITIONS.
COLD FRONT EXTENDING SOUTHWARD FROM THE LOW PUSHES EAST THROUGH
THE AREA FRIDAY NIGHT INTO SATURDAY. WEAK TO MODEST LOW LEVEL
FRONTOGENESIS RESPONSE AND Q VECTOR CONVERGENCE IS SEEN WITH THE
FRONT. MAIN 500MB SHORTWAVE TROUGH SLIDES THROUGH THE AREA
SATURDAY AFTERNOON.
AREA FORECAST SOUNDINGS ARE SHOWING GOOD COLUMN MOISTURE LATER
FRIDAY NIGHT INTO SATURDAY MORNING. QPF VALUES ARE DECENT ON
GFS/CANADIAN/ECMWF...LESS SO ON NAM. CONTINUED WITH HIGH CHANCE
POPS FOR THIS PERIOD...AND WOULD NEED TO RAISE THEM LATER ON IF
MODELS CONTINUE TO SHOW GOOD AGREEMENT. LEFT SLIGHT CHANCE FOR
THUNDER WITH WEAK ELEVATED CAPE. STILL WARM AHEAD OF FRONT WITH
SOUTH WINDS.
COLD AIR ADVECTION OCCURS BEHIND FRONT LATER SATURDAY INTO
SATURDAY NIGHT...WITH HIGH PRESSURE MOVING EASTWARD TOWARD THE
REGION. BRISK WEST WINDS SATURDAY AFTERNOON TAPER OFF SATURDAY
NIGHT...BRINGING MORE SEASONAL TEMPERATURES FOR SATURDAY NIGHT.
SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
ECMWF AND GFS ARE IN SOMEWHAT BETTER AGREEMENT WITH FEATURES
DURING THIS PERIOD. THEY TAKE HIGH PRESSURE EAST ACROSS THE REGION
SUNDAY AND SUNDAY NIGHT...THEN EAST OF THE REGION ON MONDAY. THIS
SHOULD RESULT IN QUIET WEATHER WITH NEAR NORMAL TEMPERATURES.
ECMWF AND GFS ARE IN A BIT MORE OF AN AGREEMENT WITH THE NEXT LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION EARLY NEXT WEEK. THE GFS
IS A BIT FURTHER NORTH WITH THE LOW TRACK AND SOMEWHAT STRONGER
THAN THE ECMWF. THE GFS TAKES THE LOW FROM SOUTHEAST NEBRASKA AT
00Z TUESDAY TO NEAR LA CROSSE WISCONSIN BY 00Z WEDNESDAY...AND
WEAKENS AS IT SHIFTS TO NORTHERN LAKE MICHIGAN BY 00Z THURSDAY.
THE ECMWF TAKES IT FROM THE SOUTHERN HIGH PLAINS AT 00Z TUESDAY TO
SOUTHEAST WISCONSIN BY 00Z WEDNESDAY...THEN WELL EAST OF THE
REGION BY 00Z THURSDAY. GFS TAKES MAIN SHORTWAVE TROUGH EAST
THROUGH THE REGION DURING THIS TIME...WITH THE ECMWF TAKING IT
THROUGH MAINLY NORTHERN WISCONSIN.
MORE DIFFERENCES SHOW UP ON WEDNESDAY...WITH THE GFS KEEPING THE
LOW AND 500MB LOW OVER THE REGION WITH QPF...AND THE ECMWF DRY
WITH WEAK HIGH PRESSURE.
REGARDLESS OF THE MODEL DIFFERENCES...IT LOOKS LIKE A WET PERIOD
MONDAY NIGHT INTO WEDNESDAY ACROSS THE AREA. THE BEST CHANCES
WOULD BE ON TUESDAY. INCREASED POPS OVER INITIAL MODEL BLEND GIVEN
BETTER CONFIDENCE IN THE MODEL TRENDS WITH POPS. TEMPERATURES
LOOK TO DROP TO BELOW SEASONAL NORMALS DURING THIS TIME.
AVIATION/12Z TAFS/...GROUND FOG WILL AFFECT SRN WI INCLUDING THE
TAF SITES THIS AM. VSBYS WILL HAVE A WIDE RANGE FROM 1/4 TO 3
MILES...WHICH IS TYPICAL OF GROUND FOG. MOST OF THE FOG WILL END
BY 14Z WITH VFR CONDITIONS AND FEW-SCT HIGH CLOUDS THE REMAINDER
OF THE DAY INTO THE EVENING. THIS FOG WILL OCCUR AGAIN MAINLY
AFTER 06Z TNT ALONG WITH SCT STRATOCUMULUS AROUND 4 KFT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
FRIDAY THROUGH WEDNESDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
704 AM CDT THU OCT 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 225 AM CDT THU OCT 10 2013
NO FORECAST CONCERNS FOR THE SHORT TERM PERIOD WITH QUIET WEATHER
CONTINUING.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A NORTHERN STREAM UPPER TROUGH CROSSING BRITISH COLUMBIA...A
DEEP UPPER LOW/TROUGH OVER SOUTHERN CALIFORNIA...AND STRONG RIDGING
FROM EASTERN TEXAS THROUGH THE EASTERN GREAT LAKES. VERY LITTLE
CLOUD COVER TO SPEAK OF FROM THE CENTRAL PLAINS INTO THE FORECAST
AREA... EXCEPT FOR A BAND OF CIRRUS ASSOCIATED WITH A SHORTWAVE
LIFTING THROUGH WESTERN IA. THE LACK OF CLOUD COVER IS A RESULT OF
PLENTIFUL DRY AIR SEEN ON 00Z SOUNDINGS FROM GRB...DVN...MPX...OAX
AND DDC. AT THE SURFACE...LOW PRESSURE WAS DEVELOPING OVER EASTERN
COLORADO WHILE HIGH PRESSURE WAS PRESENT OVER LOWER MICHIGAN. THE
PRESSURE GRADIENT BETWEEN THESE FEATURES OVER THE FORECAST AREA IS
LIGHTER THAN THIS TIME YESTERDAY...RESULTING IN LIGHTER WINDS AND
THEREFORE COOLER TEMPERATURES. THE TYPICAL WISCONSIN COLD SPOTS HAVE
DROPPED INTO THE UPPER 30S...MEANWHILE HIGHER TERRAIN SITES ALONG
AND WEST OF THE MISSISSIPPI RIVER WHICH ARE EXPERIENCING MORE WIND
ARE IN THE LOW TO MID 50S. AIRMASS REMAINS ABNORMALLY WARM...
THOUGH...WITH 00Z SOUNDINGS SHOWING 925MB TEMPERATURES OF 15-17C
EAST TO WEST.
THE DRY CONDITIONS WILL CONTINUE FOR ANOTHER 24 HOURS AS THE
FORECAST AREA REMAINS SITUATED IN A BLOCKED UPPER LEVEL PATTERN.
THAT PATTERN FEATURES THE UPPER LOW IN SOUTHERN CALIFORNIA PROGGED
TO EJECT NORTHEASTWARD TOWARDS THE BLACK HILLS OF SOUTH DAKOTA BY
12Z FRIDAY...WHILE STRONG RIDGING HOLDS IN PLACE OVER LOWER
MICHIGAN. EXPECT WINDS TO INCREASE...A RESULT OF THE PRESSURE
GRADIENT TIGHTENING AHEAD OF THE DEEPENING SURFACE LOW IN COLORADO
LIFTING NORTH WITH THE UPPER LOW. THE STRONGER SOUTHERLY WINDS DO
NOT BRING ANY WARMER AIR IN FOR TODAY AT 925MB...AS MODEL FORECASTS
SUGGESTS 925MB TEMPERATURES END UP AGAIN BETWEEN 16-18C AT 00Z. THUS
HIGHS ARE LIKELY TO BE SIMILAR TO THOSE SEEN YESTERDAY. HOWEVER...
THE WINDS WILL HELP TO KEEP THE NEAR SURFACE LAYER MORE MIXED
TONIGHT...RESULTING IN A WARMER NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 225 AM CDT THU OCT 10 2013
FORECAST CONCERNS ARE ON WINDS FRIDAY...PRECIPITATION CHANCES LATE
FRIDAY THROUGH SATURDAY...AND PRECIPITATION CHANCES AGAIN EARLY NEXT
WEEK.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT THAT THE UPPER AND SURFACE LOWS OVER
WESTERN SOUTH DAKOTA FRIDAY MORNING WILL CONTINUE LIFTING
NORTH-NORTHEAST...AND BEGIN PHASING FRIDAY NIGHT WITH THE NORTHERN
STREAM TROUGH CURRENTLY OVER BRITISH MARCHING EAST. AS THIS PHASING
OCCURS...THE SYSTEMS COLD FRONT LOOKS PROGGED TO MOVE THROUGH THE
FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY. ANOTHER SHORTWAVE
TROUGH LOOKS TO MOVE INTO THE AREA LATE SATURDAY BUT LITTLE IMPACT
IS SUGGESTED WITH IT. ATTENTION THEN FOCUSES BACK WEST AS ANOTHER
DEEP UPPER TROUGH IS PROGGED TO DEVELOP OVER THE WESTERN U.S..
ECMWF/GFS/CANADIAN AND THEIR RESPECTIVE ENSEMBLES ARE COMING INTO
BETTER AGREEMENT OF THIS UPPER TROUGH EJECTING EASTWARD SLOWLY
TOWARDS THE FORECAST AREA MONDAY NIGHT THROUGH WEDNESDAY. A
RELATIVELY STRONG SURFACE SYSTEM LOOKS TO ACCOMPANY THIS
TROUGH...SETTING UP A GOOD CHANCE OF RAIN DURING THIS
PERIOD...ESPECIALLY MONDAY NIGHT AND TUESDAY.
DETAILS...
WINDS ON FRIDAY REMAIN IN FOCUS AS A TIGHT PRESSURE GRADIENT IS
FORECAST OVER THE AREA AHEAD OF THE DAKOTAS LOW. THE BEST
JUXTAPOSITION OF HIGHEST PRESSURE GRADIENT MAGNITUDE AND MIXING
APPEARS TO OCCUR OVER SOUTHEAST MN. MOMENTUM TRANSFER FROM SOUNDINGS
SUGGEST GUSTS OVER THE HIGHER TERRAIN OF SOUTHEAST MN OF 35 KT...AND
PERHAPS BRIEFLY UP TO 40 KT. THUS...THE CONCERN FOR A MARGINAL WIND
ADVISORY PERSISTS. ELSEWHERE...GUSTS OF 25-30 KT SEEM REASONABLE.
THESE WINDS OUT OF THE SOUTH HELP TO ADVECT IN 925MB TEMPS OF
16-18C...ALLOWING HIGH TEMPERATURES TO END UP SLIGHTLY WARMER THAN
TODAY.
NEXT CONCERN IS ON PRECIPITATION CHANCES. A WARM CONVEYOR BELT OF
PRECIPITATION AHEAD OF THE LOW SHOULD BE LIFTING THROUGH WESTERN
PORTIONS OF IOWA AND MINNESOTA FRIDAY MORNING. ALL INDICATIONS...
MINUS THE 10.00Z ECMWF...ARE THAT THIS BELT OF PRECIPITATION WILL
FALL APART AS IT PUSHES TOWARDS THE FORECAST AREA FRIDAY
AFTERNOON...RESULTING FROM RUNNING INTO DRIER AIR AND THE DYNAMIC
FORCING LIFTING NORTH. THE ECMWF HOLDS PRECIPITATION TOGETHER TO
AFFECT SOUTHEAST MN AND NORTHEAST IA. FOR NOW HAVE KEPT FRIDAY
MOSTLY DRY FROM THE PREVIOUS FORECAST...BUT INTRODUCED A SPRINKLES
MENTION. AN INCREASE IN CLOUDS IS LIKELY LATER IN THE DAY NO MATTER
WHAT. THERE IS GOOD MODEL AGREEMENT FRIDAY NIGHT AND ESPECIALLY ON
SATURDAY THAT A BAND OF SHOWERS WILL FORM AROUND THE COLD FRONT
MARCHING EAST. THIS PRECIPITATION IS A RESULT OF MID LEVEL
FRONTOGENESIS FORCING AND A STREAM OF 1-1.3 INCH PRECIPITABLE WATER
VALUES ADVECTING NORTH PROVIDING MOISTURE. THE FORECAST PROBLEM IS
WHERE THE PRECIPITATION ENDS UP AS MODELS DIFFER ON FRONTAL TIMING.
TIMING OF THE FRONT TO GET THROUGH THE ENTIRE AREA VARIES FROM 12Z
SATURDAY ACCORDING TO THE 10.00Z NAM...15Z SATURDAY FROM THE 10.00Z
GFS...18Z SATURDAY FROM THE 10.00Z CANADIAN/ECMWF AND ABOUT 21Z
SATURDAY FROM THE 10.00Z UKMET/09.12Z ECMWF. IF THE FRONT ENDS UP
SLOWER...THE GREATER THE CHANCE AT LEAST THE SOUTHEAST HALF OF THE
FORECAST AREA WILL SEE RAIN. FOR NOW...HAVE STAYED WITH A CONSENSUS
APPROACH WHICH RESULTS IN MAXIMUM CHANCES IN THE 30-35 PERCENT
RANGE.
TEMPERATURES DEFINITELY LOOK COOLER FOR THE WEEKEND AS 925MB
READINGS FALL TO 10-13C ON SATURDAY AND 8-10C ON SUNDAY.
DRY CONDITIONS ARE LIKELY SATURDAY NIGHT THROUGH AT LEAST MONDAY
MORNING AS THE AREA IS UNDER THE INFLUENCE OF HIGH PRESSURE.
ATTENTION THEN TURNS TO THE UPPER TROUGH AND LOW PRESSURE SYSTEM
COMING OUT OF THE WESTERN U.S. AND PLAINS. PRECIPITABLE WATER VALUES
AGAIN CLIMB TO 1-1.3 INCHES OR UP TO 200 PERCENT OF NORMAL AHEAD OF
THE SYSTEM. THE COMBINATION OF THIS MOISTURE...FRONTOGENETICAL AND
DPVA FORCING WILL ALL COMBINE TO SPREAD PRECIPITATION ACROSS THE
UPPER MIDWEST WITH THIS SYSTEM. MODEL TIMING OF THIS PRECIPITATION
TO AFFECT THE FORECAST AREA IS REALLY CENTERING ON MONDAY NIGHT AND
TUESDAY...THUS HAVE RAISED PRECIPITATION CHANCES CONSIDERABLY FOR
THIS TIME PERIOD. MUCAPE IS ALMOST NIL WITH THE SYSTEM...RESULTING
FROM NEARLY MOIST-ADIABATIC LAPSE RATES...THUS HAVE KEPT THE MENTION
OF THUNDER OUT OF THE FORECAST. THE FORECAST AREA LOOKS TO BECOME
AFFECTED BY THE COLD CONVEYOR BELT OF THE SYSTEM TUESDAY NIGHT AND
WEDNESDAY...RESULTING IN THE NEED TO CARRY 30-50 PERCENT CHANCES.
THESE MAY NEED TO BE RAISED LATER AS THE SYSTEM TRACK FIRMS UP.
THERMAL FIELDS ARE WARM ENOUGH TO KEEP THE PRECIPITATION TYPE AS
RAIN...BUT WITH 925MB TEMPS DROPPING TO 3-6C ON WEDNESDAY...IT IS
GOING TO FEEL MUCH COLDER THAN WHAT WE HAVE SEEN AS OF LATE.
&&
.AVIATION...TODAY AND TONIGHT
704 AM CDT THU OCT 10 2013
MAIN CONCERN FOR AVIATION REMAINS WIND GUSTS...AS VFR CONDITIONS
WILL PREVAIL THROUGH THE PERIOD. WITH LOW PRESSURE ACROSS THE
DAKOTAS AND HIGH PRESSURE OVER THE GREAT LAKES...AREA REMAINS IN
SOUTHERLY FLOW. GRADIENT NOT QUITE AS STRONG AS THE PAST FEW DAYS
SO DO NOT ANTICIPATE WINDS TO BE QUITE AS HIGH TODAY. BUT THAT
WILL CHANGE TOMORROW AS THE MAIN SHORT WAVE TROUGH EJECTS THROUGH
THE UPPER MIDWEST. ANTICIPATE WIND GUSTS OF 30-40 KTS ON
FRIDAY...BUT THAT IS BEYOND THIS TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
225 AM CDT THU OCT 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 225 AM CDT THU OCT 10 2013
NO FORECAST CONCERNS FOR THE SHORT TERM PERIOD WITH QUIET WEATHER
CONTINUING.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A NORTHERN STREAM UPPER TROUGH CROSSING BRITISH COLUMBIA...A
DEEP UPPER LOW/TROUGH OVER SOUTHERN CALIFORNIA...AND STRONG RIDGING
FROM EASTERN TEXAS THROUGH THE EASTERN GREAT LAKES. VERY LITTLE
CLOUD COVER TO SPEAK OF FROM THE CENTRAL PLAINS INTO THE FORECAST
AREA... EXCEPT FOR A BAND OF CIRRUS ASSOCIATED WITH A SHORTWAVE
LIFTING THROUGH WESTERN IA. THE LACK OF CLOUD COVER IS A RESULT OF
PLENTIFUL DRY AIR SEEN ON 00Z SOUNDINGS FROM GRB...DVN...MPX...OAX
AND DDC. AT THE SURFACE...LOW PRESSURE WAS DEVELOPING OVER EASTERN
COLORADO WHILE HIGH PRESSURE WAS PRESENT OVER LOWER MICHIGAN. THE
PRESSURE GRADIENT BETWEEN THESE FEATURES OVER THE FORECAST AREA IS
LIGHTER THAN THIS TIME YESTERDAY...RESULTING IN LIGHTER WINDS AND
THEREFORE COOLER TEMPERATURES. THE TYPICAL WISCONSIN COLD SPOTS HAVE
DROPPED INTO THE UPPER 30S...MEANWHILE HIGHER TERRAIN SITES ALONG
AND WEST OF THE MISSISSIPPI RIVER WHICH ARE EXPERIENCING MORE WIND
ARE IN THE LOW TO MID 50S. AIRMASS REMAINS ABNORMALLY WARM...
THOUGH...WITH 00Z SOUNDINGS SHOWING 925MB TEMPERATURES OF 15-17C
EAST TO WEST.
THE DRY CONDITIONS WILL CONTINUE FOR ANOTHER 24 HOURS AS THE
FORECAST AREA REMAINS SITUATED IN A BLOCKED UPPER LEVEL PATTERN.
THAT PATTERN FEATURES THE UPPER LOW IN SOUTHERN CALIFORNIA PROGGED
TO EJECT NORTHEASTWARD TOWARDS THE BLACK HILLS OF SOUTH DAKOTA BY
12Z FRIDAY...WHILE STRONG RIDGING HOLDS IN PLACE OVER LOWER
MICHIGAN. EXPECT WINDS TO INCREASE...A RESULT OF THE PRESSURE
GRADIENT TIGHTENING AHEAD OF THE DEEPENING SURFACE LOW IN COLORADO
LIFTING NORTH WITH THE UPPER LOW. THE STRONGER SOUTHERLY WINDS DO
NOT BRING ANY WARMER AIR IN FOR TODAY AT 925MB...AS MODEL FORECASTS
SUGGESTS 925MB TEMPERATURES END UP AGAIN BETWEEN 16-18C AT 00Z. THUS
HIGHS ARE LIKELY TO BE SIMILAR TO THOSE SEEN YESTERDAY. HOWEVER...
THE WINDS WILL HELP TO KEEP THE NEAR SURFACE LAYER MORE MIXED
TONIGHT...RESULTING IN A WARMER NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 225 AM CDT THU OCT 10 2013
FORECAST CONCERNS ARE ON WINDS FRIDAY...PRECIPITATION CHANCES LATE
FRIDAY THROUGH SATURDAY...AND PRECIPITATION CHANCES AGAIN EARLY NEXT
WEEK.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT THAT THE UPPER AND SURFACE LOWS OVER
WESTERN SOUTH DAKOTA FRIDAY MORNING WILL CONTINUE LIFTING
NORTH-NORTHEAST...AND BEGIN PHASING FRIDAY NIGHT WITH THE NORTHERN
STREAM TROUGH CURRENTLY OVER BRITISH MARCHING EAST. AS THIS PHASING
OCCURS...THE SYSTEMS COLD FRONT LOOKS PROGGED TO MOVE THROUGH THE
FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY. ANOTHER SHORTWAVE
TROUGH LOOKS TO MOVE INTO THE AREA LATE SATURDAY BUT LITTLE IMPACT
IS SUGGESTED WITH IT. ATTENTION THEN FOCUSES BACK WEST AS ANOTHER
DEEP UPPER TROUGH IS PROGGED TO DEVELOP OVER THE WESTERN U.S..
ECMWF/GFS/CANADIAN AND THEIR RESPECTIVE ENSEMBLES ARE COMING INTO
BETTER AGREEMENT OF THIS UPPER TROUGH EJECTING EASTWARD SLOWLY
TOWARDS THE FORECAST AREA MONDAY NIGHT THROUGH WEDNESDAY. A
RELATIVELY STRONG SURFACE SYSTEM LOOKS TO ACCOMPANY THIS
TROUGH...SETTING UP A GOOD CHANCE OF RAIN DURING THIS
PERIOD...ESPECIALLY MONDAY NIGHT AND TUESDAY.
DETAILS...
WINDS ON FRIDAY REMAIN IN FOCUS AS A TIGHT PRESSURE GRADIENT IS
FORECAST OVER THE AREA AHEAD OF THE DAKOTAS LOW. THE BEST
JUXTAPOSITION OF HIGHEST PRESSURE GRADIENT MAGNITUDE AND MIXING
APPEARS TO OCCUR OVER SOUTHEAST MN. MOMENTUM TRANSFER FROM SOUNDINGS
SUGGEST GUSTS OVER THE HIGHER TERRAIN OF SOUTHEAST MN OF 35 KT...AND
PERHAPS BRIEFLY UP TO 40 KT. THUS...THE CONCERN FOR A MARGINAL WIND
ADVISORY PERSISTS. ELSEWHERE...GUSTS OF 25-30 KT SEEM REASONABLE.
THESE WINDS OUT OF THE SOUTH HELP TO ADVECT IN 925MB TEMPS OF
16-18C...ALLOWING HIGH TEMPERATURES TO END UP SLIGHTLY WARMER THAN
TODAY.
NEXT CONCERN IS ON PRECIPITATION CHANCES. A WARM CONVEYOR BELT OF
PRECIPITATION AHEAD OF THE LOW SHOULD BE LIFTING THROUGH WESTERN
PORTIONS OF IOWA AND MINNESOTA FRIDAY MORNING. ALL INDICATIONS...
MINUS THE 10.00Z ECMWF...ARE THAT THIS BELT OF PRECIPITATION WILL
FALL APART AS IT PUSHES TOWARDS THE FORECAST AREA FRIDAY
AFTERNOON...RESULTING FROM RUNNING INTO DRIER AIR AND THE DYNAMIC
FORCING LIFTING NORTH. THE ECMWF HOLDS PRECIPITATION TOGETHER TO
AFFECT SOUTHEAST MN AND NORTHEAST IA. FOR NOW HAVE KEPT FRIDAY
MOSTLY DRY FROM THE PREVIOUS FORECAST...BUT INTRODUCED A SPRINKLES
MENTION. AN INCREASE IN CLOUDS IS LIKELY LATER IN THE DAY NO MATTER
WHAT. THERE IS GOOD MODEL AGREEMENT FRIDAY NIGHT AND ESPECIALLY ON
SATURDAY THAT A BAND OF SHOWERS WILL FORM AROUND THE COLD FRONT
MARCHING EAST. THIS PRECIPITATION IS A RESULT OF MID LEVEL
FRONTOGENESIS FORCING AND A STREAM OF 1-1.3 INCH PRECIPITABLE WATER
VALUES ADVECTING NORTH PROVIDING MOISTURE. THE FORECAST PROBLEM IS
WHERE THE PRECIPITATION ENDS UP AS MODELS DIFFER ON FRONTAL TIMING.
TIMING OF THE FRONT TO GET THROUGH THE ENTIRE AREA VARIES FROM 12Z
SATURDAY ACCORDING TO THE 10.00Z NAM...15Z SATURDAY FROM THE 10.00Z
GFS...18Z SATURDAY FROM THE 10.00Z CANADIAN/ECMWF AND ABOUT 21Z
SATURDAY FROM THE 10.00Z UKMET/09.12Z ECMWF. IF THE FRONT ENDS UP
SLOWER...THE GREATER THE CHANCE AT LEAST THE SOUTHEAST HALF OF THE
FORECAST AREA WILL SEE RAIN. FOR NOW...HAVE STAYED WITH A CONSENSUS
APPROACH WHICH RESULTS IN MAXIMUM CHANCES IN THE 30-35 PERCENT
RANGE.
TEMPERATURES DEFINITELY LOOK COOLER FOR THE WEEKEND AS 925MB
READINGS FALL TO 10-13C ON SATURDAY AND 8-10C ON SUNDAY.
DRY CONDITIONS ARE LIKELY SATURDAY NIGHT THROUGH AT LEAST MONDAY
MORNING AS THE AREA IS UNDER THE INFLUENCE OF HIGH PRESSURE.
ATTENTION THEN TURNS TO THE UPPER TROUGH AND LOW PRESSURE SYSTEM
COMING OUT OF THE WESTERN U.S. AND PLAINS. PRECIPITABLE WATER VALUES
AGAIN CLIMB TO 1-1.3 INCHES OR UP TO 200 PERCENT OF NORMAL AHEAD OF
THE SYSTEM. THE COMBINATION OF THIS MOISTURE...FRONTOGENETICAL AND
DPVA FORCING WILL ALL COMBINE TO SPREAD PRECIPITATION ACROSS THE
UPPER MIDWEST WITH THIS SYSTEM. MODEL TIMING OF THIS PRECIPITATION
TO AFFECT THE FORECAST AREA IS REALLY CENTERING ON MONDAY NIGHT AND
TUESDAY...THUS HAVE RAISED PRECIPITATION CHANCES CONSIDERABLY FOR
THIS TIME PERIOD. MUCAPE IS ALMOST NIL WITH THE SYSTEM...RESULTING
FROM NEARLY MOIST-ADIABATIC LAPSE RATES...THUS HAVE KEPT THE MENTION
OF THUNDER OUT OF THE FORECAST. THE FORECAST AREA LOOKS TO BECOME
AFFECTED BY THE COLD CONVEYOR BELT OF THE SYSTEM TUESDAY NIGHT AND
WEDNESDAY...RESULTING IN THE NEED TO CARRY 30-50 PERCENT CHANCES.
THESE MAY NEED TO BE RAISED LATER AS THE SYSTEM TRACK FIRMS UP.
THERMAL FIELDS ARE WARM ENOUGH TO KEEP THE PRECIPITATION TYPE AS
RAIN...BUT WITH 925MB TEMPS DROPPING TO 3-6C ON WEDNESDAY...IT IS
GOING TO FEEL MUCH COLDER THAN WHAT WE HAVE SEEN AS OF LATE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1141 PM CDT WED OCT 9 2013
THE MAIN FOCUS FOR THE TAF SITES IS ON LOW CHANCES FOR RIVER
VALLEY FOG AT LSE FOLLOWED BY HOW STRONG WINDS WILL BE THURSDAY.
SURFACE WINDS HAVE DROPPED OFF IN THE VALLEY WITH LSE AT 4-6KTS
THOUGH WINDS JUST ABOVE IT ARE STILL BLOWING AT 10-20KTS. IT DOES
NOT LOOK LIKE AN OVERLY FAVORABLE SETUP FOR VALLEY FOG...BUT THERE
IS AN OUTSIDE CHANCE THAT SOMETHING COULD FORM ALONG THE LA CROSSE
RIVER VALLEY AND DRAIN TO THE WEST TOWARD THE AIRPORT.
OTHERWISE...WINDS WILL PICK UP THURSDAY MORNING WITH SOME GUSTS IN
THE 16-20KT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1155 PM CDT WED OCT 9 2013
.UPDATE...
&&
.AVIATION/06Z TAFS/...
LIGHTER WIND REGIME IN THE BOUNDARY LEVEL TONIGHT SO SOME CONCERN
FOR FOG IN THE EASTERN INLAND AREAS...POTENTIALLY AFFECTING THE
KENW/KUES CORRIDOR. SREF PROBS WERE LOW BUT THE HRRR BRINGS VSBYS
DOWN TO 1/4 MILE FROM SOUTH OF SHEBOYGAN TO KENOSHA. WILL INCLUDE
SOME FOG BUT NOT GO QUITE AS WIDESPREAD AS THE HRRR SHOWS. THE
DENSE LIFR FOG WOULD LIKELY BE IN THE TYPICAL LOW AREA/RIVER VALLEYS
UNTIL 13Z.
OTHERWISE MOSTLY CLEAR SKIES WITH ONLY SOME SCATTERED CIRRUS.
&&
.PREV DISCUSSION... /ISSUED 306 PM CDT WED OCT 9 2013/
TONIGHT AND THURSDAY - CONFIDENCE...HIGH
QUIET WEATHER CONTINUES. HIGH PRESSURE REMAINS ACROSS THE EASTERN
U.S. WITH A NEARLY STATIONARY TROUGH OF LOW PRESSURE IN THE PLAINS.
THE SOUTHERLY FLOW PERSISTS WITH AN ONSHORE FLOW AS WELL. AIRMASS
REMAINS DRY WITH ONLY A BIT OF CIRRUS. 925 TEMPS SUPPORT MORE IN THE
WAY OF ABOVE NORMAL TEMPERATURES.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE EXITS TO THE EAST WHILE STRONG LOW PRESSURE MOVES
FROM THE HIGH PLAINS OF ERN COLORADO...NORTHEAST TO EASTERN NORTH
DAKOTA BY FRIDAY EVENING. THE TIGHTENING PRESSURE GRADIENT WILL
BRING BREEZY SOUTHERLY WINDS TO SOUTHERN WISCONSIN BY FRIDAY
AFTERNOON. GUSTS COULD REACH 30 MPH WEST OF MADISON...LOWER IN THE
EAST. THE STRONGEST WINDS JUST OFF THE SURFACE ARRIVE FRIDAY
EVENING...BUT WE DECOUPLE WITH SUNSET WHICH WILL LIMIT WIND
SPEEDS. OTHERWISE...STILL DRY AND WARM FOR MID OCTOBER.
FRIDAY NIGHT AND SATURDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
A COLD FRONT ASSOCIATED WITH THE LOW TRACKING NORTH INTO CANADA
WILL SWEEP THROUGH ON SATURDAY. SHOWERS ALONG AND AHEAD OF IT
COULD ARRIVE IN THE WEST AFTER MIDNIGHT FRIDAY NIGHT. THE MODELS
ARE IN BETTER AGREEMENT WITH TIMING. THERE IS A SECONDARY MID
LEVEL SHORT WAVE THAT SWINGS NORTHEAST INTO THE AREA ON
SATURDAY...ENHANCING THE FROTOGENESIS AND OMEGA WITH THE FRONT. IN
ADDITION...ALTHOUGH MOISTURE WILL BE LACKING WITH THE FRONT WHEN
IT IS UPSTREAM...WE SHOULD SEE A RIBBON OF HIGHER DEWPOINTS MOVE
INTO THE AREA. ALL THIS LOOKS TO COME TOGETHER ACROSS THE AREA ON
SATURDAY...SO WILL MAINTAIN HIGH CHC POPS FOR NOW...AND IF
CONFIDENCE INCREASES...THOSE POPS WILL RISE. THERE IS SOME
CAPE...BUT NOT IMPRESSIVE...SO WILL MAINTAIN JUST A SLIGHT CHANCE
OF STORMS. LOOKING AT TIMING...AREAS WEST OF MADISON MAY BE
CLEARING OUT BY AFTERNOON WITH THE RAIN ENDING BY EARLY EVENING IN
THE EAST.
SUNDAY AND MONDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
COOLER HIGH PRESSURE ARRIVES IN THE WAKE OF THE LOW WITH
TEMPERATURES FALLING BACK TO LEVELS MORE NORMAL FOR THE TIME OF
YEAR.
TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
A NICE MEATY SYNOPTIC SYSTEM IS EXPECTED TO COME THROUGH DURING
THIS PERIOD. IT/S STARTING TO LOOK MORE FALL-LIKE WITH THESE TYPES
OF SYSTEMS SPINNING THROUGH.
THE GFS AND ECMWF WERE AT ODDS ON TIMING OVER THE LAST FEW
RUNS...BUT HAVE COME INTO SYNC WITH BOTH THE TIMING AND THE
GENERAL TRACK OF THE LOW. RAIN SHOULD MOVE LATE MONDAY NIGHT AND
CONTINUE INTO WEDNESDAY MORNING. THE HEAVIEST RAIN LOOKS TO BE
TUESDAY AFTERNOON AND EVENING. NO FEAR OF ANY SNOW FLAKES AS
TEMPERATURES WILL BE TOO WARM. THEN EVEN COOLER TEMPERATURES
ARRIVE LATE NEXT WEEK.
AVIATION/00Z TAFS/...VFR MOSTLY SKC THIS PERIOD. LIGHTER WIND REGIME
OFF THE DECK TONIGHT SO SOME CONCERN FOR FOG IN THE EASTERN INLAND
AREAS...POTENTIALLY AFFECTING THE KENW/KUES CORRIDOR. SREF PROBS ARE
VERY LOW. SO FOR NOW WILL INCLUDE SOME FOG BUT NOT GO QUITE AS LOW
AS MOS SUGGESTS AT THIS POINT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...HENTZ
TONIGHT/THURSDAY AND AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
415 AM CDT SAT OCT 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING
INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN
AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT
FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15.
THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH
TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL.
ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL
FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH
A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM
NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS
TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT
SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL
15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP
MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS
OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL
MN TODAY.
TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK
THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS
BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES
IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH
COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH
30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL
COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE
GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND
THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS
FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP
THEIR FIRST 32 OR COLDER LOW THIS SEASON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH
PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW
AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS
RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE
FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS
TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW
REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST
FOUR NIGHTS IS BEST WITH THE ECWMF. THIS SOLUTION RECEIVED THE
MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN
AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL
LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING
I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI
MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN
WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE
TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE
FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A
THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH
CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS.
RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY
SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL
KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT
RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE
LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT
LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH
THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF
THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF
CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE
COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH...
STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME...
THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY
WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN
PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW
ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE
UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT-
OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM
LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED
NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1224 AM CDT SAT OCT 12 2013
COLD FRONT JUST NOW MOVING INTO WI. SHRA/TSRA AHEAD OF THE
BOUNDARY HAS REALLY FALLEN APART...SO PARED BACK PRECIP MENTION
AT EAU TO A VCSH. MVFR/VFR STRATUS HAS MOVED INTO WRN MN BEHIND
THE BOUNDARY...BUT LEADING EDGE OF STRATUS IS MOVING NNE TOWARD
LAKE SUPERIOR AND MAY CLIP MSP AT BEST. NAM AND RAP SHOW THESE
CLOUDS MORE OR LESS REMAINING STATIONARY UNTIL AFTER 12Z AS NEXT
SHORT WAVE COMES OUT OF THE DAKOTAS AND INTO MN. CONFIDENCE IS
HIGH IN MVFR CIGS RESULTING FOR MUCH OF THE DAY ACROSS CENTRAL
MN...BUT IS A FAIR AMOUNT OF UNCERTAINTY WITH HOW LOW CIGS WILL BE
DOWN TOWARD THE TWIN CITIES. AT THE VERY LEAST CU RULE OFF THE
NAM/RAP WOULD SAY MIXING AND CAA WILL COMBINE BRING BKN CIGS ABOUT
AS FAR SOUTH AS MKT THIS AFTERNOON. ANY ADDITIONAL PRECIP WILL BE
MOVING INTO WRN MN AFTER 14Z AND WILL MAINLY IMPACT CENTRAL
MN...SO HAVE VCSH MENTIONS AT AXN/STC. WINDS WILL REMAIN GUSTY
ACROSS WRN MN THROUGH THE NIGHT...BUT WILL RELAX SOME ACROSS ERN
MN/WRN WI. GUSTY WSW WINDS RETURN FOR SUNDAY...THOUGH NOT AS
STRONG AS WAS SEEN SATURDAY. SUNDAY NIGHT...HIGH PRESSURE WILL
BEGIN MOVING IN WHICH WILL FINALLY START TO RELAX THE WINDS AND
CLEAR OUT THE SKIES.
KMSP...THE FIELD MAY GET CLIPPED BY A BATCH OF MVFR CIGS BETWEEN 8
AND 10Z...BUT LOOKS MORE LIKELY THAT MVFR CIGS WEST OF MSP WILL
HEAD MORE FOR THE NORTH METRO. MAIN CLOUD MASS WILL MOVE IN LATE
SUNDAY MORNING. FOR NOW KEPT THIS VFR...THOUGH SOME CIGS DOWN TO
AROUND 025 MAY BE POSSIBLE. ANY SHOWERY ACTIVITY TODAY WILL REMAIN
WELL NORTH OF MSP.
/OUTLOOK FOR KMSP/
MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS.
TUE...MVFR/IFR WITH SHRA. WINDS NNE 7-12 KTS.
WED...CHANCE MVFR/SHRA IN MORNING. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
319 AM CDT SAT OCT 12 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM CDT SAT OCT 12 2013
VERTICALLY STACKED SYSTEM IS LIFTING NWD INTO SOUTH CENTRAL CANADA
AT 08Z. SEVERAL FRONTAL BOUNDARIES FROM THIS SYSTEM WILL AFFECT THE
FA THROUGH THE DAY AND INTO THIS EVENING. AS THESE FRONTS PROGRESS
THROUGH THE AREA...SEVERAL PIECES OF SHORT WAVE ENERGY WILL ROTATE
OVERHEAD AND GENERATE SOME SHOWERS. BEST OPPORTUNITY FOR RAIN WILL
BE THIS AFTERNOON OVER THE WESTERN TWO THIRDS OF THE FA. RAIN FALL
AMOUNTS WILL BE ON THE LIGHT SIDE EXCEPT OVER THE BORDERLAND WHERE
UP TO .20 INCHES MAY FALL. SOME BREAKS IN THE CLOUD COVER ARE
POSSIBLE...ESPECIALLY OVER NW WI WHICH WILL ALLOW MAX TEMPS TO REACH
INTO THE UPPER 50S TO AROUND 60...WITH LOWER TO MIDDLE 50S
ELSEWHERE.
A NEGATIVELY TILTED SHORT WAVE TROF WILL SWEEP THROUGH THE FA
TONIGHT. THE SHOWERS WILL LINGER INTO THE EVENING OVER THE NORTHERN
PORTION OF THE FA UNDERNEATH BEST FORCING FROM SAID TROF. THE
SHOWERS WILL DIMINISH OVERNIGHT. A DRY DAY IS IN STORE FOR MONDAY AS
HIGH PRESSURE SETTLES OVER THE UPPER MIDWEST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 318 AM CDT SAT OCT 12 2013
WEAK HIGH PRESSURE WILL BE IN PLACE ACROSS THE WRN GREAT LAKES SUN
NIGHT AND EARLY MONDAY...BUT WILL QUICKLY SHIFT TO THE EAST AS A
DEEP TROUGH OVER THE ROCKIES EJECTS EWD INTO THE PLAINS AND MIDWEST
THROUGH WEDNESDAY. THIS SYSTEM WILL BRING A PROLONGED PERIOD OF RAIN
TO THE NORTHLAND...ALONG WITH COOLER TEMPERATURES. THERE ARE
SIGNIFICANT DIFFERENCES IN THE TRACK OF THIS LOW PRESSURE SYSTEM
THROUGH THE CENTRAL US. THE LATEST RUNS OF THE ECMWF AND GEM ARE
MUCH SLOWER THAN THE GFS AND NAM. THE DETERMINISTIC RUN OF THE GFS
IS EVEN FASTER THAN THE GFS ENSEMBLE MEAN. SO...WILL LEAN MORE
TOWARD A SLOWER PROGRESSION OF THE RAIN THROUGH THE REGION INTO THE
MIDDLE OF THE WEEK. EVEN AS THIS TROUGH LIFTS EWD INTO NEW ENGLAND
AND ERN CANADA LATE WED AND THURSDAY...A SECONDARY RE-ENFORCING
UPPER TROUGH DROPS INTO THE UPPER MIDWEST QUICKLY ON THE HEALS OF
THE DEPARTING LOW THROUGH FRIDAY...WITH ADDITIONAL CHANCES FOR
SHOWERS. THE BEST CHANCE FOR SIGNIFICANT RAINFALL THIS WEEK APPEARS
TO BE MON NIGHT AND TUESDAY.
HIGH TEMPERATURES THROUGH THE WEEK WILL BE STEADY...IN THE 40S AND
LOWER 50S. WHILE OVER NIGHT LOWS WILL OCCASIONALLY DIP INTO THE
LOWER TO MID 30S...WITH WIDESPREAD UPPER 30S AND 40S THROUGH THE
WEEK. WOULD NOT BE SURPRISED TO SEE A FEW FLAKES MIXED IN ACROSS THE
NRN COUNTIES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1200 AM CDT SAT OCT 12 2013
MVFR CEILINGS WERE MOVING THROUGH THE AREA WITH VERTICALLY STACKED
LOW. THE RAP 900-925MB CONDENSATION PRESSURE DEFICITS WERE DOING
A DECENT JOB WITH THESE LOWER CEILINGS AND WAS USED TO IN THE
TAFS. THE MVFR CEILINGS MAY NOT REACH KHYR OR ONLY BE INTERMITTENT
THERE.
AN UPPER LEVEL TROUGH AND COLD AIR ALOFT WILL LEAD TO PLENTY OF
CU/STRATOCU BY SATURDAY AFTERNOON...WITH WIDESPREAD LOW VFR/MVFR
CEILINGS AND SOME SHOWERS. SHOWERS WILL BE MOST WIDESPREAD OVER
NORTHEAST MINNESOTA.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 54 39 55 39 / 20 10 0 0
INL 54 34 52 33 / 50 50 0 0
BRD 53 36 57 39 / 20 0 0 10
HYR 60 36 58 30 / 10 0 0 0
ASX 60 38 57 33 / 10 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...GSF
LONG TERM...BJT
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1243 AM CDT SAT OCT 12 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 310 PM CDT FRI OCT 11 2013
LEADING LINE OF CONVECTION WILL CONTINUE TO MOVE SLOWLY EAST INTO
WESTERN WISCONSIN THIS EVENING BEFORE DIMINISHING. INDIVIDUAL CELLS
WITH IN THE LINE WERE MOVING NORTHEAST CLOSE TO 60 KTS DURING THE
AFTERNOON. STILL HAD STABLE BOUNDARY LAYER INTO THE AFTERNOON WHICH
HELD SURFACE WIND GUSTS IN CHECK. THE UPPER CIRCULATION LIFTING
NORTH/NORTHEAST INTO SOUTHERN NORTH DAKOTA LATE THIS AFTERNOON.
THERE REMAINS A NARROW CORRIDOR OF INSTABILITY TO THE WEST OF THE
LINE AND VARIOUS HIRES MODELS CONTINUE TO INDICATE ANOTHER BROKEN
LINE OF CONVECTION EXPECTED TO DEVELOP AND LIFT NORTHEAST INTO
EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA INTO THIS EVENING.
STILL MAY CLIP THE NORTHWEST QUADRANT OF THE CWA INTO THIS EARLY
EVENING. STRONG SOUTHEAST TO SOUTH WINDS EXPECTED TO CONTINUE AHEAD
OF THE FEATURE GRADUALLY DIMINISHING OVERNIGHT. WILL LEAVE THE WIND
ADVISORY GO UNTIL EXPIRATION.
COLDER AIR TO WRAP IN BEHIND THE SYSTEM OVERNIGHT...WITH LOWER
CLOUDS EXPECTED TO WRAP INTO NORTHERN PORTION OF THE REGION INTO THE
DAY SATURDAY. SOME LIGHT SHOWERS ALSO WILL AFFECT THE NORTHERN AREA
AS WELL AS THE UPPER LOW EXITS THE REGION TO THE NORTHEAST. SURFACE
WINDS WILL INCREASE AGAIN SATURDAY MORNING WITH SOME GUSTS TO 30
KNOTS AGAIN FROM THE SOUTHWEST AND WEST. HIGH TEMPERATURES ARE
EXPECTED TO COOL BACK CLOSE TO AVERAGE FOR THIS TIME OF YEAR.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 310 PM CDT FRI OCT 11 2013
SURFACE HIGH PRESSURE BUILDS IN FOR SATURDAY NIGHT AND
SUNDAY...AND BRINGS A BRIEF PERIOD OF MOSTLY CLEAR SKIES AND LIGHT
WINDS. TEMPERATURES WILL COOL INTO THE MID AND UPPER 30S BY EARLY
SUNDAY MORNING...WITH PATCHY FROST EXPECTED /MAINLY ACROSS CENTRAL
MN AND WI/. SUNDAY WILL FEATURE NEAR NORMAL TEMPERATURES IN THE
UPPER 50S AND LOWER 60S...ALONG WITH MOSTLY SUNNY SKIES.
MONDAY THROUGH A LARGE PORTION OF NEXT WEEK WILL BE FOCUSED ON THE
EVOLUTION OF A WESTERN CONUS UPPER TROUGH...WHICH IS FORECAST TO
CLOSE OFF OVER THE ROCKIES AND THEN SLOWLY MEANDER ACROSS THE
CENTRAL CONUS TOWARD THE UPPER GREAT LAKES. THE 15.12Z MODEL
SOLUTIONS CONTINUED TO FEATURE THE TIMING DIFFERENCES THAT HAVE
BEEN PRESENT IN PRIOR RUNS. NAMELY...THE ECMWF IS DEEPER AND
SLOWER THAN THE GFS WITH THE LOW. THE RESULT IS ABOUT A 12 HOUR
DIFFERENCE BETWEEN THE TWO WITH RESPECT TO PRECIP ONSET/DEPARTURE.
DESPITE THE TIMING DIFFERENCES...CONFIDENCE IS HIGH THAT PRECIP
WILL ENTER WEST CENTRAL MN BY MONDAY AFTERNOON...AND THEN EXPAND
ACROSS THE AREA ON MONDAY NIGHT INTO TUESDAY. HAVE INCLUDED 80-90
POPS ACROSS THE MN PORTION OF THE FORECAST AREA...AND 60-70 POPS
ACROSS WEST CENTRAL WI. BOTH MODELS FEATURE RUN TOTAL
PRECIPITATION AMOUNTS FROM 1 TO OVER 3 INCHES ACROSS THE FORECAST
AREA BY 12Z FRIDAY.
A LARGE TROUGH IS CARVED OUT ACROSS MUCH OF CANADA AND THE
CENTRAL/EASTERN UNITED STATES INTO NEXT WEEKEND. THE ASSOCIATED
REDUCED HEIGHTS...IN COMBINATION WITH ENHANCED CLOUDINESS AND
PRECIPITATION...WILL CAUSE HIGH TEMPERATURES TO RUN AROUND 5 TO 10
DEGREES BELOW CLIMATOLOGICAL NORMALS...WITH HIGHS GENERALLY IN THE
UPPER 40S AND LOWER 50S FROM TUESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1224 AM CDT SAT OCT 12 2013
COLD FRONT JUST NOW MOVING INTO WI. SHRA/TSRA AHEAD OF THE
BOUNDARY HAS REALLY FALLEN APART...SO PARED BACK PRECIP MENTION
AT EAU TO A VCSH. MVFR/VFR STRATUS HAS MOVED INTO WRN MN BEHIND
THE BOUNDARY...BUT LEADING EDGE OF STRATUS IS MOVING NNE TOWARD
LAKE SUPERIOR AND MAY CLIP MSP AT BEST. NAM AND RAP SHOW THESE
CLOUDS MORE OR LESS REMAINING STATIONARY UNTIL AFTER 12Z AS NEXT
SHORT WAVE COMES OUT OF THE DAKOTAS AND INTO MN. CONFIDENCE IS
HIGH IN MVFR CIGS RESULTING FOR MUCH OF THE DAY ACROSS CENTRAL
MN...BUT IS A FAIR AMOUNT OF UNCERTAINTY WITH HOW LOW CIGS WILL BE
DOWN TOWARD THE TWIN CITIES. AT THE VERY LEAST CU RULE OFF THE
NAM/RAP WOULD SAY MIXING AND CAA WILL COMBINE BRING BKN CIGS ABOUT
AS FAR SOUTH AS MKT THIS AFTERNOON. ANY ADDITIONAL PRECIP WILL BE
MOVING INTO WRN MN AFTER 14Z AND WILL MAINLY IMPACT CENTRAL
MN...SO HAVE VCSH MENTIONS AT AXN/STC. WINDS WILL REMAIN GUSTY
ACROSS WRN MN THROUGH THE NIGHT...BUT WILL RELAX SOME ACROSS ERN
MN/WRN WI. GUSTY WSW WINDS RETURN FOR SUNDAY...THOUGH NOT AS
STRONG AS WAS SEEN SATURDAY. SUNDAY NIGHT...HIGH PRESSURE WILL
BEGIN MOVING IN WHICH WILL FINALLY START TO RELAX THE WINDS AND
CLEAR OUT THE SKIES.
KMSP...THE FIELD MAY GET CLIPPED BY A BATCH OF MVFR CIGS BETWEEN 8
AND 10Z...BUT LOOKS MORE LIKELY THAT MVFR CIGS WEST OF MSP WILL
HEAD MORE FOR THE NORTH METRO. MAIN CLOUD MASS WILL MOVE IN LATE
SUNDAY MORNING. FOR NOW KEPT THIS VFR...THOUGH SOME CIGS DOWN TO
AROUND 025 MAY BE POSSIBLE. ANY SHOWERY ACTIVITY TODAY WILL REMAIN
WELL NORTH OF MSP.
/OUTLOOK FOR KMSP/
MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS.
TUE...MVFR/IFR WITH SHRA. WINDS NNE 7-12 KTS.
WED...CHANCE MVFR/SHRA IN MORNING. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1200 AM CDT SAT OCT 12 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 301 PM CDT FRI OCT 11 2013
AT 300PM/2000Z...THERE WAS A STRONG AND STACKED LOW PRESSURE SYSTEM
LIFTING NNE THROUGH NORTH CENTRAL SOUTH DAKOTA. A STRONG COLD
FRONT STRETCHED FROM THE LOW THROUGH CENTRAL SOUTH
DAKOTA...CENTRAL NEBRASKA...AND CENTRAL KANSAS. THIS STORM SYSTEM
HAD MULTIPLE BANDS OF SHOWERS AND STORMS ACROSS THE
DAKOTAS...WESTERN MINNESOTA...AND SOUTHERN MANITOBA. ONE BAND OF
SHOWERS AND STORMS STRETCHED FROM NE NORTH DAKOTA THROUGH NW AND
WESTERN MINNESOTA. THE BAND WAS STEADILY MOVING NORTH AND SLOWLY
EAST. CLOUDY TO MOSTLY CLOUDY SKIES COVERED MUCH OF THE DAKOTAS
AND WESTERN AND SOUTHERN MINNESOTA...WHILE EASTERN MINNESOTA AND
WISCONSIN STILL HAD PARTLY TO MOSTLY SUNNY SKIES. THE NORTHLAND
HAD SE WINDS OF ABOUT 10 TO 20 MPH WITH GUSTS UP TO 35 MPH IN SOME
AREAS. TEMPERATURES WERE IN THE LOWER 70S ACROSS MOST OF THE
REGION...EXCEPT FOR 60S OVER THE ARROWHEAD AND UPPER 70S NEAR
BAYFIELD PENINSULA. DEW POINT TEMPERATURES WERE IN THE UPPER 40S
TO LOWER 50S.
TONIGHT...THE STRONG LOW PRESSURE SYSTEM WILL LIFT THROUGH EASTERN
NORTH DAKOTA THIS EVENING AND SOUTHERN MANITOBA LATE TONIGHT.
THE STRONG COLD FRONT WILL MOVE THROUGH THE NORTHLAND OVERNIGHT.
THE BAND OF SHOWERS AND STORMS CURRENTLY ACROSS WESTERN MINNESOTA
WILL WORK ITS WAY THROUGH AT LEAST THE WESTERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING BEFORE BEGINNING TO DISSIPATE.
ANOTHER BAND OF SHOWERS AND STORMS WILL LIKELY FOLLOW IN ITS WAKE
A FEW HOURS BEHIND THE FIRST BAND. I FORECAST HIGH CHANCES OF PCPN
FOR THE SW FORECAST AREA SINCE IT WILL LIKELY BE AFFECTED...AND WE
MAY NEED TO INCREASE PCPN CHANCES OVER OTHER PARTS OF THE FORECAST
AREA AS THE BAND OF SHOWERS AND STORMS BEGINS TO MOVE INTO THE
NORTHERN AND CENTRAL FORECAST AREA. THESE SHOWERS AND STORMS COULD
PRODUCE VERY GUSTY WINDS...PERHAPS AS HIGH AS 45 MPH...DUE TO THE
STRONG FLOW ALOFT IN THE MIXING LAYER AND JUST ABOVE THE MIXING
LAYER. AND DESPITE THE DECOUPLING THAT WILL OCCUR THIS
EVENING...THE SHOWERS COULD STILL MIX DOWN THESE STRONG GUSTS FOR
A WHILE THIS EVENING. STORM PREDICTION CENTER CONTINUES TO HAVE A
SLIGHT RISK OF SEVERE STORMS ACROSS THE FAR SW FORECAST AREA. THIS
IS DUE TO THE STRONG LOW LEVEL SHEAR AND STRONG LOW LEVEL FLOW
WHICH COULD PRODUCE DAMAGING WINDS AND ISOLATED TORNADOES WITH
STORMS...BUT THE LIMITING FACTOR IS CAPE...ESPECIALLY SURFACE
BASED CAPE. OVERNIGHT LOWS SHOULD BE IN THE UPPER 40S TO MID 50S.
SATURDAY...THE NORTHLAND WILL HAVE A CLOUDY AND WINDY DAY IN THE
WAKE OF THE COLD FRONT AS A POTENT SHORTWAVE LIFTS THROUGH THE
NORTHLAND AND SURROUNDING REGION. THE SW WINDS OF 15 TO 20 MPH
WILL GUST UP TO 30 MPH. THE COLD AIR ALOFT AND STRONG MIXING WILL
HELP GENERATE THICK CLOUD COVER AND RAIN SHOWERS. I LOWERED THE
HIGH TEMPERATURES TO THE LOW 50S ACROSS NE MINNESOTA AND THE UPPER
50S TO NEAR 60 DEGREES ACROSS NW WISCONSIN. WE MAY NEED TO LOWER
THE TEMPERATURES A BIT MORE DEPENDING ON HOW QUICKLY THE HEAVY
CLOUD COVER DEVELOPS AND/OR MOVES INTO THE NORTHLAND.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 301 PM CDT FRI OCT 11 2013
AN UPPER LEVEL TROUGH WILL SWING ACROSS THE NORTHLAND SATURDAY
NIGHT...RESULTING IN SOME EVENING SHOWERS ACROSS THE REGION. THE
GUSTY SOUTHWEST TO WEST WINDS WILL ALSO CONTINUE INTO THE NIGHT
BEFORE SUBSIDING SOME OVERNIGHT. SKIES WILL GRADUALLY START TO
CLEAR LATER IN THE NIGHT FROM WEST TO EAST. THE NEXT SYSTEM WILL
ALREADY START TO AFFECT THE REGION LATER SUNDAY...AS HIGH AND MID
CLOUDS INCREASE ACROSS AT LEAST THE SW PART OF THE REGION. THE
MODELS INDICATE SOME PRECIPITATION MAY MAKE IT INTO THE CWA LATER
SUNDAY NIGHT...ESPECIALLY IN THE BRAINERD LAKES REGION. BEYOND
THAT...IT IS SHAPING UP TO BE A VERY WET PERIOD MONDAY INTO
WEDNESDAY. THERE ARE SOME DIFFERENCES AMONGST THE DETERMINISTIC
MODELS...ESPECIALLY WITH RESPECT TO TIMING AND SPEED OF THE
SYSTEM...BUT OVERALL IT LOOKS LIKE IT WILL BE A WET EARLY TO
MIDDLE PART OF THE UPCOMING WORK WEEK. TEMPERATURES WILL BE KEPT
COOLER BY THE RAIN AND CLOUDS. THE GFS AND ECMWF DISAGREE TO SOME
EXTENT DURING THE LATTER PART OF THE WORK WEEK AS WELL...BUT BOTH
MODELS MAINTAIN SOME SORT OF UNSETTLED WEATHER WITH SOME SCATTERED
SHOWERS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1200 AM CDT SAT OCT 12 2013
A FRONTAL BOUNDARY WAS MOVING THROUGH THE NORTHLAND LATE THIS
EVENING...WITH A BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM
KINL TO K04W AT 0430Z. THIS BAND WAS MOVING NORTHEAST. THE NMM-WRF
WAS DOING A GOOD JOB DEPICTING THIS BAND OF RAIN...AND FORECASTS IT
TO DIMINISH IN INTENSITY/COVERAGE AROUND 08Z.
MVFR CEILINGS WERE MOVING TOWARD KBRD BEHIND THIS FRONT AND SHOULD
PROGRESS NORTH AND EAST OVERNIGHT. THE RAP 900-925MB CONDENSATION
PRESSURE DEFICITS WERE DOING A DECENT JOB WITH THESE LOWER CEILINGS
AND WAS USED TO IN THE TAFS. THE MVFR CEILINGS MAY NOT REACH KHYR OR
ONLY BE INTERMITTENT THERE.
AN UPPER LEVEL TROUGH AND COLD AIR ALOFT WILL LEAD TO PLENTY OF
CU/STRATOCU BY SATURDAY AFTERNOON...WITH WIDESPREAD LOW VFR/MVFR
CEILINGS AND SOME SHOWERS. SHOWERS WILL BE MOST WIDESPREAD OVER
NORTHEAST MINNESOTA.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 50 54 38 54 / 60 50 10 0
INL 52 53 35 52 / 50 60 30 10
BRD 48 54 36 57 / 60 50 10 0
HYR 53 61 36 58 / 40 10 10 0
ASX 55 61 39 57 / 40 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 9 AM CDT SUNDAY FOR LSZ140-141.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM...DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1114 PM CDT Fri Oct 11 2013
.UPDATE:
Issued at 929 PM CDT Fri Oct 11 2013
Scattered showers and thunderstorms currently extending from
northwest Missouri through southeast Kansas is in response to
upstream upper air pertubation over eastern Colorado southwest
Kansas moving east-northweastward into northern and central
Kansas. Cold frontal boundary extending from western Iowa through
northeast Kansas then south-central Kansas continues too move east
and southeastward. We delayed the arrival of showers and
thunderstorms over most areas in the LSX CWA. Believe shower and
thunderstorm activitly will be moving into Qunicy - Columbia area
after 0700 UTC and into St. Louis area after 10 or 11 UTC. Would
not be surprise if a new band of convection forms after midhight ahead
of the current bands observed on EAX and SGF radars. RAP and local
LSX WRF models supporting this tread. Instability not too
impressive at this time over area. Well defined subsidence
inversion at 780 mb noted at SGF sounding this evening. This might
challenge convection a little. However colder air aloft over
western Kansas may increase the instability early Saturday
morning. Adjusted temps a little over CWA.
Przybylinski
&&
.SHORT TERM: (Through Late Tonight)
Issued at 318 PM CDT Fri Oct 11 2013
Although upstream front/dry line remain tranquil at 20z, believe
that modest instability and convergence along the front should
initiate scattered convection over the next few hours. The coverage
of this activity should then increase later tonight as upstream
shortwave currently near the 4 corners works into the region. It
may take a while for the upstream convection to work into the CWA,
but amount of moisture, instability, and lift all suggest scattered
convection will threaten much of the CWA late tonight and during the
predawn hours. For now have placed the highest PoPs at 50% west of
a KFAM-KTAZ line, with PoPs tapering off southeast of this line to
low chance in KSLO area by daybreak. For now have stayed with
overnight lows in the 50s with the thinking that there should be a
bit of cooling due to precip; however if convection does remain
isolated these lows will likely be too cool by a cat or so.
Truett
.LONG TERM: (Saturday through Next Friday)
Issued at 318 PM CDT Fri Oct 11 2013
Overall forecast trends appear on track for tomorrow with scattered
showers and thunderstorms expected to persist from tonight into
Saturday. A stacked low pressure system over the northern Plains
will lift into Canada by tomorrow morning while at least one
secondary vort max rotates around its back side, providing another
source of lift for MO/IL. The occluding system will also continue to
draw a narrow ribbon of moisture through the area ahead of the cold
front (PW values will be near +2 SD). In addition, models are
forecasting a coupled jet structure at H3 which places the LSX CWA
beneath the favored region for enhanced lift, especially between
12-18z. The combination of these factors should be sufficient for
isolated to scattered precipitation, but this does not look like a
widespread rainfall event because of the spatially limited moisture
and overall weak forcing.
Precipitation should end fairly quickly after the cold front moves
through the region due to increasing subsidence with a 1025 hPa high
pressure center that will be sliding into the northern Plains and
western Great Lakes on Saturday night and Sunday. This area of high
pressure will push the cold front to near the MO/AR border before
cyclogenesis over the central Plains occurs and lifts the stalled
boundary back northward as a warm front on Tuesday. There are still
some model differences regarding the upper level disturbance which
will be responsible for the surface low, but recent runs of the
ECMWF/GFS/GEM all agree at that least a portion of that energy will
lift through the central CONUS on Monday night and Tuesday. The
moisture and dynamics are expected to be much better with the
Mon/Tue system. Depending on how the upper level disturbance splits
apart, the other half could move across the area during the middle
or end of the week and provide additional precipitation chances.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1053 PM CDT Fri Oct 11 2013
Cold front extending from a sfc low over nern ND south through
nwrn MO and sern KS will move sewd through UIN and COU late tgt,
and through the St Louis metro area Saturday mrng. Scattered
showers and thunderstorms are along and just ahead of this front
this evng. A band of VFR, low-mid level clouds well ahead of the
front in COU and UIN this evng will advect into the St Louis metro
area late tgt. Showers and a few storms should move through UIN
and COU late tgt, and through the St Louis metro area around 12z
Saturday. The s-sely sfc wind will veer around to a nwly direction
after fropa in UIN and COU by early Saturday mrng and in the St
Louis metro area by late mrng. The low level clouds will clear out
in the mrng in UIN and COU, and in the aftn in the St Louis metro
area as a ridge of high pressure builds into the area behind the
cold front.
Specifics for KSTL: Clouds at 5000-7000 ft will advect into STL
just after 06z Saturday with scattered showers moving into the STL
area by 12z Saturday. The showers will move out by late mrng with
the clouds clearing out in the aftn. Sely sfc wind will veer
around to a swly direction Saturday mrng, and a nwly direction
Saturday aftn.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT FRI OCT 11 2013
.UPDATE...
ISSUED AT 910 PM CDT FRI OCT 11 2013
CHANGES ARE ON THE WAY AS A COLD FRONT WILL COME THROUGH THE
REGION TONIGHT. A FIRST ROUND OF ISOLATED TO SCATTERED SHOWERS HAS
MOVED INTO NW WI/SE MN/NE IA ALONG A WEAKENING LEAD MID LEVEL
TROUGH. FURTHER TO THE WEST...A NARROW BAND OF SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ALONG A STRONG FRONTOGENETIC BAND
ALONG THE SURFACE COLD FRONT. INSTABILITY IS RATHER LIMITED WITH
12.01Z LAPS ANALYSIS SHOWING ABOUT 500 J/KG OF MUCAPE ACROSS SOUTH
CENTRAL MINNESOTA. RECENT MESO MODELS SEEM TO HAVE A DECENT IDEA
OF SHOWING THE LATEST DEVELOPMENT ALONG THE COLD FRONT WITH A
GRADUAL WEAKENING OF THE INSTABILITY/FGEN ALONG/AHEAD OF THE FRONT
OVERNIGHT. LOW LEVEL TO DEEP WIND SHEAR IS MORE THAN SUPPORTIVE OF
SEVERE WEATHER...BUT THE LACK OF INSTABILITY AND DEEP FORCING
ABOVE THE SURFACE/LOW LEVELS WILL KEEP THIS CONVECTION LOW TOPPED
AND NOT SEVERE.
ONCE THE FRONT MOVES THROUGH...WINDS WILL SHIFT TO THE WEST AND
REMAIN GUSTY ON INTO THE AFTERNOON SATURDAY. HAVE BUMPED UP THE
GUSTS THERE BUT IT DOES NOT LOOK HIGH ENOUGH TO WARRANT AN
ADVISORY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
AT 3 PM...A 990 MB SURFACE LOW WAS LOCATED JUST NORTH OF PIERRE
SOUTH DAKOTA. DURING THE PAST 3 HOURS...MSAS DATA SHOWS THAT THE
SURFACE PRESSURE HAS FALLEN 4 MB ACROSS NORTHEAST SOUTH DAKOTA.
MEANWHILE THE PRESSURE HAS RISEN 6 MB ACROSS THE NEBRASKA
PANHANDLE. LAPS SHOWS THE TROPOSPHERIC FOLD EXTENDING DOWN
800 MB. MEANWHILE FURTHER SOUTHEAST...THERE IS A 1019 MB SURFACE
HIGH CENTERED OVER KENTUCKY. THE TIGHT SURFACE PRESSURE GRADIENT
BETWEEN THESE TWO SYSTEMS HAS RESULTED IN WIND GUSTS AS HIGH AS
41 MPH /149 PM/ AT ROCHESTER INTERNATIONAL AIRPORT AND 39 MPH
/133 PM/ AT THE DODGE CENTER AWOS. A BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUES TO BE LOCATED ACROSS NORTH-CENTRAL IOWA
AND SOUTH-CENTRAL MINNESOTA. THIS IS LOCATED IN AN AREA OF DEEP
MOISTURE CONVERGENCE.
FOR TONIGHT...THE LATEST RAP SHOW THAT THE 850 MB MOISTURE
TRANSPORT WILL GRADUALLY WEAKEN AND SHIFT NORTHEAST INTO NORTHERN
WISCONSIN THIS EVENING. IN ADDITION...THE 900 TO 800 MB
FRONTOGENESIS WILL GRADUALLY WEAKEN AS IT MOVES EAST ACROSS THE
FORECAST AREA. THIS WILL RESULT IN THE ECHO COVERAGE BECOMING MORE
SCATTERED. THIS SHOWS UP WELL IN THE RAP...NMM...AND ARW. AS A
RESULT...KEPT THE PRECIPITATION CHANCES IN THE 15 TO 24 PERCENT
RANGE. ML CAPES GRADUALLY DECREASE FROM AROUND 500 J/KG LATE THIS
AFTERNOON TO LESS THAN 200 J/KG AFTER MIDNIGHT. DUE TO
THIS...CONFINED THE ISOLATED THUNDERSTORMS TO THE EVENING. LIKE
YESTERDAY...IT APPEARS THAT THE SHEAR WILL BE TOO GREAT FOR THE
AMOUNT OF INSTABILITY AVAILABLE...THUS ANY THUNDERSTORMS THAT DO
HAPPEN DEVELOP WILL LIKELY GET SHEARED APART QUICKLY. WITH LOSS OF
DIURNAL HEATING LATE THIS AFTERNOON AND EARLY EVENING...EXPECT THE
WIND GUSTS TO QUICKLY WANE.
ON SATURDAY MORNING...THE 11.12Z MODELS APPEAR TO BE JUST A BIT
SLOWER AT MOVING THE FRONT OUT OF THE AREA. AS A RESULT...HELD
ONTO A SLIGHT CHANCE OF SHOWERS IN CENTRAL AND SOUTHWEST WISCONSIN
THROUGH 12.14Z.
ON SATURDAY EVENING...ANOTHER SHORT WAVE TROUGH MOVES EAST THROUGH
THE REGION. LIKE YESTERDAY...THE BEST SYNOPTIC FORCING AND
MOISTURE LOOKS TO BE WELL NORTH OF THE FORECAST AREA. AS A
RESULT...KEPT THE FORECAST DRY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 PM CDT FRI OCT 11 2013
ON SATURDAY NIGHT...A CANADIAN HIGH WILL BUILD ACROSS THE AREA.
WITH THE CENTER OF THIS HIGH BEING LOCATED MORE ACROSS IOWA THAN
OUR FORECAST AREA. THINKING THAT THERE MIGHT BE JUST ENOUGH MIXING
IN THE BOUNDARY LAYER TO PREVENT THE TEMPERATURES BOTTOMING OUT AS
MUCH AS THEY WILL BE UNDERNEATH THE CORE OF THE HIGH. AS A RESULT...
KEPT LOW TEMPERATURES IN THE 35 TO 42 DEGREE RANGE. THE WARMEST
TEMPERATURES WILL BE FOUND IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS. MEANWHILE THE REMAINDER OF THE AREA WILL BE COLD ENOUGH
FOR SOME FROST TO DEVELOP.
ON SUNDAY NIGHT...THE COMBINATION OF LIGHT WINDS AND MOSTLY CLEAR
SKIES ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN WILL ALLOW
TEMPERATURES TO FALL INTO THE MID 30S. THESE TEMPERATURES WILL BE
COLD ENOUGH FOR SOME FROST TO DEVELOP.
FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO
LOW THAT A CLOSED 500 MB LOW WILL MOVE THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY. THE MAIN QUESTION IS WHEN EXACTLY WILL
THIS OCCUR. THE 11.12Z ECMWF IS A BIT SLOWER THAN ITS PREVIOUS RUN
AND SLOWER THAN SOME OF THE OTHER DETERMINISTIC MODELS. AS
RESULT NOT EXACTLY SURE WHICH TIME PERIOD /MONDAY NIGHT...TUESDAY...
OR BOTH/ TO GO WITH CATEGORICAL PRECIPITATION CHANCES /80 TO
100 PERCENT/. WITH THIS UNCERTAINTY...JUST STAYED WITH THE ALL
BLEND SOLUTION. A COUPLE OF DAYS AGO...IT LOOKED LIKE WE WOULD
POTENTIALLY SEE SOME THUNDERSTORMS AHEAD OF THIS LOW...BUT THE
MODELS NOW SUGGEST THAT WE WILL ONLY SEE RAIN FROM THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1151 PM CDT FRI OCT 11 2013
A COLD FRONT MOVING THROUGH THE REGION WILL BRING WINDS AROUND
FROM THE SOUTHEAST TO THE WEST TONIGHT AS IT PASSES. SHOWERS AND
THUNDERSTORMS THAT HAD DEVELOPED AHEAD OF IT IN A THIN LINE HAS
STARTED TO FALL APART AS CONVECTION FURTHER SOUTH IN IOWA HAS
TAKEN OVER SOME OF THE MOISTURE RETURN. RST HAS THE GREATER
CHANCES OF HAVING SOME OF THE CURRENT SHOWERS IN ITS
VICINITY...BUT AM GROWING MORE CONFIDENT THAT THEY WILL NOT REACH
LSE. WINDS WILL BECOME GUSTY OUT OF THE WEST AT BOTH SITES WITH
SOME GUSTS IN THE 20-30KT RANGE IN THE AFTERNOON. EXPECT THAT SOME
DIURNAL CUMULUS WILL DEVELOP AS WELL IN THE 3-5KFT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1016 AM CDT SAT OCT 12 2013
.DISCUSSION...
1015 AM CDT
MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES
HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST
MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID
70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY
IN THE UPPER 60S.
THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES
TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND
THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY
DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY
ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS
WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE
TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN
SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED
SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES
SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON
THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED
CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW
HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM
850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF
ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE
FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN
THE SLIGHT CHANCE OF THUNDER.
TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH
FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT
HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL
LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS
THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH
FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST
AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO
THE SCATTERED SHOWER ARRIVAL.
MTF
&&
.PREV DISCUSSION...
256 AM CDT
TODAY...
THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY
LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING
AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE
IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN
KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER
SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN
IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE
SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET
OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE
FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS
SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR
ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING.
MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID
AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA.
GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60
DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT
RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE
REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE
NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED
VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY
WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS
MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT
BEHIND.
TONIGHT THROUGH MONDAY NIGHT...
PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH
PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD
ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY
DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS
PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE
ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND
CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE
30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP
TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA.
FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO
MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES
WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE
WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO
INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH
DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST
RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT
RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY
NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN...
EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS
COOLER SIDE OF GUIDANCE.
TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT
EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER
SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID
LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT
RANGE TO THE MID MISSOURI VALLEY.
TUESDAY THROUGH FRIDAY...
STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING
WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH
A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL
MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED
SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK
DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY
SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD
TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE
TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE
LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND
MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY.
PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO
END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A
BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A
PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD
AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C//
WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A
PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS
LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL
TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SCATTERED SHOWERS LATE THIS MORNING THROUGH MID AFTERNOON WITH A
CHANCE FOR ISOLATED THUNDER BETWEEN 18Z-20Z.
* A POSSIBLE 2-3 HOUR PERIOD OF MVFR CIGS ALONG THE COLD FRONT
LATER THIS AFTERNOON...MAINLY BETWEEN 21Z AND 00Z.
* WIND SHIFT FROM SOUTH TO WEST-SOUTHWEST LATE THIS AFTERNOON
WITH COLD FRONTAL PASSAGE. A SHIFT TO NORTHERLY IS EXPECTED
SUNDAY MORNING.
MDB/MTF
//DISCUSSION...UPDATED 12Z...
STRONG LOW PRESSURE IS MOVING NORTH-NORTHEAST ACROSS FAR SOUTHEAST
MANITOBA HAS A COLD FRONTAL BOUNDARY STRETCHING SOUTHWARD FROM IT
WHICH IS JUST NOW REACHING THE MISSISSIPPI RIVER NEAR THE QUAD
CITIES. SEVERAL WEAK WAVES APPEAR TO BE EMBEDDED IN THE UPPER
FLOW PATTERN. A NARROW BAND OF SHOWERS HAS DEVELOPED OUT AHEAD OF
THE FRONT IN CONJUNCTION WITH THE ACTIVE UPPER FLOW. THE EASTWARD
PUSH OF THIS BAND HAS BEEN SLOW BUT IT LOOKS TO CONTINUE THROUGH
THE MORNING. THE FRONT WILL TRY TO CATCH UP TO THE UPPER FORCING
THROUGH THE DAY SO ANY GAP BETWEEN THE CURRENT ACTIVITY NEAR RFD
AND ACTIVITY NEAR THE FRONT TO THE WEST MAY CLOSE WITH TIME. WILL
CONTINUE WITH A FEW HOURS OF TEMPO SHOWERS ACROSS THE TERMINALS
INTO THE AFTERNOON. STILL CANNOT RULE OUT THUNDER BUT THUNDER
COVERAGE LOOKS TO BE ISOLATED OVER THE AREA WITH THE THREAT TOO
LOW TO MENTION IN THE TAFS AT THIS TIME. BRIEF MVFR CIGS MAY
ACCOMPANY THE FRONTAL PASSAGE BUT THESE LOOKS TO BE SHORT LIVED SO
WILL CARRY PREVAILING LOWER END VFR CLOUD COVER.
SOUTH-SOUTHEAST WINDS WILL INCREASE IN SPEED WITH TIME THIS
MORNING AND TURN MORE SOUTH OR EVEN SOUTH-SOUTHWEST BEFORE TURNING
SOUTHWEST THEN WEST WITH THE APPROACH AND PASSAGE OF THE FRONT
THROUGH THE AFTERNOON. SPEEDS WILL EASE UP OVERNIGHT AS HIGH
PRESSURE ARRIVES KEEPING QUIET WEATHER IN PLACE. WINDS WILL THEN
TURN MORE NORTHERLY SUNDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN SCATTERED SHOWERS IN THE AREA FROM 17Z-20Z.
LOW CONFIDENCE IF THUNDER WILL OCCUR AT THE AIRPORT ITSELF.
* LOW CONFIDENCE IF MVFR CIGS WILL MATERIALIZE LATER THIS
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS.
MDB/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
&&
.MARINE...
125 AM CDT
DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH
DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS
FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE
PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE
NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE
20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH
30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD
FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS
AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND
EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL
MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY
THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE
WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY
NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS
QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS
AS THE RIDGE APPROACHES.
THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY
NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS
THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER
BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE
NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE
CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS
DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT
WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN
WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN
FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE
TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1134 AM EDT SAT OCT 12 2013
.UPDATE...
ISSUED AT 1122 AM EDT SAT OCT 12 2013
STRATUS AROUND THE WESTERN EDGE OF THE EAST COAST CLOSED LOW HAS
ADVECTED ABOUT A THIRD TO A HALF OF THE WAY WEST ACROSS THE CWA THIS
MORNING. THE WESTERN EDGE OF THIS IS NEAR THE KY HIGHWAY 15 CORRIDOR
IN EASTERN KY. DAYTIME HEATING MAY TEND TO WHITTLE AWAY AT THE
WESTERN TO SOUTHWESTERN EDGE OF THIS...BUT SUFFICIENT MOISTURE IS ALSO
IN PLACE FOR SOME PANCAKE CU TO THE WEST OF THIS. THE STRATUS SHOULD
BECOME MORE STRATOCU AND CU IN NATURE AS THE AFTERNOON PROGRESSES AND
MIX OUT TO AN EXTENT. THE TUG VALLEY NEAR THE WV BORDER APPEARS TO BE
DESTINED TO BE CLOUDY THE LONGEST.
THE CLOUD COVER WILL AFFECT DAYTIME HIGHS AND THEY HAVE BEEN ADJUSTED
DOWNWARD ACCORDINGLY A FEW DEGREES IN THE EASTERN HALF OF THE
CWA...ESPECIALLY NEAR THE WV BORDER.
UPDATE ISSUED AT 758 AM EDT SAT OCT 12 2013
LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST.
THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN
TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE
UPDATED FORECAST GRIDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM EDT SAT OCT 12 2013
A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR
DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR
EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT.
WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS
TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE
EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS
COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE
WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE
LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY
THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE
CAPPED BELOW THE -20C LEVEL.
WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN
TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS
WHERE CLOUDS ARE MORE SIGNIFICANT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 413 AM EDT SAT OCT 12 2013
BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD
AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE
APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND
A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE
LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT
WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT
WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY
SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED
FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY.
LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS
CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN
AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN
KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS
MONDAY TO ACCOUNT FOR THIS.
SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG
500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE
SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE
LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE
GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN
SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS
TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH
MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN
MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES
KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH
THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME
PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO
THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE
FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT
PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON
ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO
MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD
FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 758 AM EDT SAT OCT 12 2013
LOW CLOUDS WITH MVFR AND IFR CEILINGS WERE SPREADING WESTWARD INTO
THE FORECAST AREA EARLY THIS MORNING. WEST OF THE CLOUD DECK...
VALLEY FOG WAS PREVALENT NEAR RIVERS...LAKES...AND LARGE STREAMS...
BRINGING AREAS OF VLIFR. THE FOG WILL DISSIPATE THIS MORNING. THE
CLOUD DECK IS EXPECTED TO CONTINUE A SLOW WESTWARD PROGRESSION...BUT
ALSO SLOWLY RISE AND BEGIN TO BREAK UP WITH TIME TODAY...GIVING WAY
TO MAINLY VFR THIS AFTERNOON. VALLEY FOG SHOULD DEVELOP AGAIN LATE
TONIGHT...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE EASTERN PART
OF THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
758 AM EDT SAT OCT 12 2013
.UPDATE...
ISSUED AT 758 AM EDT SAT OCT 12 2013
LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST.
THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN
TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE
UPDATED FORECAST GRIDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM EDT SAT OCT 12 2013
A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR
DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR
EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT.
WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS
TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE
EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS
COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE
WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE
LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY
THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE
CAPPED BELOW THE -20C LEVEL.
WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN
TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS
WHERE CLOUDS ARE MORE SIGNIFICANT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 413 AM EDT SAT OCT 12 2013
BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD
AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE
APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND
A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE
LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT
WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT
WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY
SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED
FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY.
LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS
CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN
AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN
KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS
MONDAY TO ACCOUNT FOR THIS.
SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG
500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE
SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE
LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE
GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN
SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS
TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH
MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN
MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES
KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH
THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME
PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO
THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE
FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT
PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON
ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO
MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD
FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 758 AM EDT SAT OCT 12 2013
LOW CLOUDS WITH MVFR AND IFR CEILINGS WERE SPREADING WESTWARD INTO
THE FORECAST AREA EARLY THIS MORNING. WEST OF THE CLOUD DECK...
VALLEY FOG WAS PREVALENT NEAR RIVERS...LAKES...AND LARGE STREAMS...
BRINGING AREAS OF VLIFR. THE FOG WILL DISSIPATE THIS MORNING. THE
CLOUD DECK IS EXPECTED TO CONTINUE A SLOW WESTWARD PROGRESSION...BUT
ALSO SLOWLY RISE AND BEGIN TO BREAK UP WITH TIME TODAY...GIVING WAY
TO MAINLY VFR THIS AFTERNOON. VALLEY FOG SHOULD DEVELOP AGAIN LATE
TONIGHT...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE EASTERN PART
OF THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
520 AM CDT SAT OCT 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING
INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN
AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT
FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15.
THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH
TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL.
ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL
FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH
A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM
NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS
TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT
SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL
15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP
MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS
OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL
MN TODAY.
TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK
THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS
BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES
IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH
COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH
30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL
COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE
GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND
THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS
FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP
THEIR FIRST 32 OR COLDER LOW THIS SEASON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH
PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW
AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS
RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE
FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS
TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW
REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST
FOUR NIGHTS IS BEST WITH THE ECMWF. THIS SOLUTION RECEIVED THE
MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN
AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL
LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING
I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI
MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN
WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE
TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE
FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A
THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH
CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS.
RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY
SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL
KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT
RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE
LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT
LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH
THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF
THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF
CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE
COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH...
STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME...
THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY
WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN
PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW
ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE
UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT-
OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM
LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED
NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 520 AM CDT SAT OCT 12 2013
WITH SFC LOW MOVING NEARLY DUE NORTH ACROSS SRN CANADA...POST
FRONTAL STRATUS ACROSS WRN MN HAS STAYED PUT MOST OF THE NIGHT.
STILL EXPECT IT TO HEAD EAST THIS MORNING...REACHING WRN WI BY THE
AFTERNOON AS A STRONG SHORT WAVE MOVES FROM THE DAKOTAS ACROSS
CENTRAL MN. FOLLOWED THE RAP/NAM FOR BRINGING THESE CLOUDS BACK
ACROSS TERMINALS TODAY. ALSO FOLLOWED THE IDEA OF THE RAP WITH
MVFR CIGS STAYING CONFINED TO CENTRAL MN...WITH CIGS WORKING INTO
MSP/RNH/EAU BEING OF THE VFR VARIETY. GUSTY WINDS WILL RETURN BY
15Z...THOUGH OUT OF THE WSW TODAY. NOT EXPECTING GUSTS LIKE WERE
SEEN FRIDAY...BUT SHOULD STILL SEE GUSTS UP NEAR 30 KTS IN WRN MN
AND 25 KTS OVER IN WI THIS AFTERNOON. TONIGHT...HIGH PRESSURE
ARRIVES AND WITH IT A SLACKENING OF THE WINDS AND A CLEARING OF
THE SKIES.
KMSP...MAY SEE A BRIEF MVFR CIG WHEN STRATUS MOVES BACK IN AROUND
17Z...OTHERWISE VFR CONDITIONS WILL PREVAIL. CONFIDENCE HIGH IN
ALL OTHER ASPECTS OF THE TAF.
/OUTLOOK FOR KMSP/
MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS.
TUE...MVFR/IFR WITH SHRA. WINDS NE 5 KTS.
WED...MVFR. CHANCE SHRA. WINDS NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
928 AM CDT SAT OCT 12 2013
.UPDATE...
UPDATED TO INCREASE PRECIPITATION CHANCES FOR EARLY AFTERNOON.
&&
.DISCUSSION...
LINE OF CONVECTION CONTINUES TO HOLD TOGETHER AS IT BEGINS TO MOVE
INTO EASTERN ARKANSAS THIS MORNING. THIS LINE SHOULD MAKE IT TO
THE MISSISSIPPI RIVER JUST BEFORE NOON...SO HAVE INCREASED RAIN
CHANCES IN THIS CORRIDOR FROM ROUGHLY 12-3 PM. HAVE ALSO
INCREASED THE SHOWER INTENSITY TO MODERATE BASED ON REFELCTIVITY
TRENDS AND CURRENT RAINFALL AMOUNTS. STORMS HAVE BEEN PRODUCING
GUSTS IN THE 20 TO 30 MPH RANGE...BUT WITH A FEW MORE HOURS OF
HEATING THEY COULD INTENSIFY TO PRODUCE GUSTS NEAR 40 MPH.
ALL OTHER FORECAST PARAMETERS ARE CURRENTLY ON TRACK.
JAB
&&
.PREV DISCUSSION... /ISSUED 617 AM CDT SAT OCT 12 2013/
DISCUSSION... /ISSUED 501 AM CDT SAT OCT 12 2013/
A RATHER ACTIVE PATTERN OVER THE NEXT SEVEN DAYS. ABOVE NORMAL
TEMPS WILL CONTINUE TODAY... BUT WILL LIKELY BE TEMPERED A BIT BY
INCREASED CLOUDS AHEAD OF SHORTWAVE LIFTING INTO THE MID MS RIVER
VALLEY. THIS FEATURE HAD AIDED THUNDERSTORM DEVELOPMENT OVER
EASTERN OK EARLY THIS MORNING. CONVECTIVE POTENTIAL WILL SPREAD
INTO EASTER AR LATE THIS MORNING/EARLY AFTERNOON...WITH THE
SHORTWAVE PASSING BY TO THE NORTH. NAM BUFR SOUNDINGS FOR
JONESBORO DEPICTED SURFACE BASED CAPE AROUND 1500 J/KG AT 19Z...
ACCOMPANIED BY MODEST SHEAR. A FEW STORMS MAY CROSS THE RIVER INTO
WEST TN... BUT SHOULD WEAKEN AS THEY MOVE FURTHER INTO THE
MIDLEVEL RIDGE. BY THIS EVENING... THE SHORTWAVE WILL HAVE MOVED
WELL OFF THE NORTHEAST AND THE BOUNDARY LAYER WILL HAVE
STABILIZED. A SURFACE COLD FRONT WILL DROP INTO THE MIDSOUTH AND
STALL TONIGHT BEHIND THE EXITING MIDLEVEL SHORTWAVE. SLIGHTLY
DRIER AIR AND SHORTWAVE RIDGING SHOULD KEEP RAIN CHANCES AT BAY
FOR SUNDAY.
BY MONDAY AFTERNOON... THE FIRST IN A SERIES OF SHORTWAVES WILL
EJECT FROM A DEEP UPPER TROF CENTERED OVER CENTRAL ROCKIES. THIS
SHORTWAVE WILL ARRIVE OVER THE OZARKS MONDAY EVENING AS IT DEAMPLIFIES.
LOW LEVEL FLOW WILL VEER IN RESPONSE TO THE APPROACHING UPPER
LEVEL WAVE LATE MONDAY/EARLY TUESDAY...RETURNING MODIFIED GULF
AIR THE MIDSOUTH. GFS PROGS PRECIPITABLE WATER VALUES NEAR 1.9
INCHES BY TUESDAY AFTERNOON.
GFS AND ECMWF MODELS LIFT THE CENTER OF THE DEEP AND BROAD LONGWAVE
TROF FROM THE ROCKIES INTO THE CENTRAL PLAINS BY WEDNESDAY...
LOWERING HEIGHTS OVER MUCH OF CONUS. A SURFACE COLD FRONT WILL LAY OUT
NEARLY PARALLEL TO THE SOUTHWEST FLOW ALOFT...BEFORE DROPPING
THROUGH THE MIDSOUTH WITH A SHORTWAVE TROF PASSAGE LATE WEDNESDAY.
GIVEN THE PREFRONTAL MOISTURE PLUME AND COLD FRONTAL PASSAGE...
RAIN CHANCES APPEAR GOOD TUESDAY AND WEDNESDAY.
BY LATE WEDNESDAY... THE GFS AND ECMWF BEGIN TO PART WAYS. THE GFS
KEEPS A RIDGE WEST/TROF EAST PATTERN THROUGH THE WEEKEND...KEEPING THE
MIDSOUTH IN DRY NORTHWEST FLOW ALONG. CONVERSELY...THE ECMWF
DROPS SIGNIFICANT UPPER LEVEL ENERGY FROM WESTERN CANADA INTO THE
THE FOUR CORNERS REGION BY FRIDAY...THEN EJECTS AN OPEN BUT HIGHLY
AMPLIFIED TROF INTO THE CENTRAL AND SOUTHERN PLAINS BY LATE
SATURDAY. THE ECMWF SOLUTION WOULD RESULT IN POTENTIALLY ACTIVE
WEATHER ACROSS THE MIDSOUTH ON SATURDAY...A VERY DIFFERENT SOLUTION
THAN THAT OF THE GFS.
EXTENDED FORECAST PERIODS WERE HEAVILY WEIGHTED TOWARD THE ECMWF...
GIVEN THE ECMWF/S GREATER RECENT RUN TO RUN CONSISTENCY. WITH THE
LACK OF GFS CONCURRENCE...FORECAST CONFIDENCE IS BELOW AVERAGE
FOR THE LATE WEEK PERIODS.
PWB
&&
.AVIATION...
12Z TAF SET
PATCHY FOG IS OCCURRING AGAIN THIS MORNING AT KMKL REDUCING VSBYS
TO MVFR OR IFR AT TIMES. FOG WILL LIFT AFTER 13Z. SCT TSRAS WILL
DEVELOP TODAY ACROSS THE CWA AHEAD OF AN APPROACHING COLD FRONT.
WILL CONTINUE MENTION OF VCTS FOR NOW. EXPECT GENERALLY VFR
CONDITIONS UNLESS A TAF SITE IS AFFECTED BY A TSRA. AFTER
01Z...EXPECT TSRAS TO DIE OUT. NOT SURE ABOUT CLOUD COVER DURING
THE EVENING INTO THE OVERNIGHT HOURS. RAP INDICATES THERE COULD BE
SOME LOWER CIGS OCCUR DURING AT LEAST THE EVENING HOURS AND
CURRENTLY ON SATELLITE THERE IS SOME LOWER CIGS IN OKLAHOMA ALONG
FRONT. OTHER MODELS SCATTER CLOUDS OUT. FOR NOW WILL CONTINUE
WITH VFR CONDITIONS BUT WILL CHANGE FROM SCT040 SCT120 TO BKN040.
CAN/T RULE OUT SOME PATCHY FOG AT KMKL AGAIN LATE TONIGHT. LIGHT S
WINDS WILL BECOME NE THIS EVENING.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 81 60 80 59 / 60 10 10 10
MKL 79 57 80 54 / 30 20 0 0
JBR 77 57 77 54 / 70 10 10 10
TUP 83 60 80 59 / 20 10 0 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
617 AM CDT SAT OCT 12 2013
.DISCUSSION... /ISSUED 501 AM CDT SAT OCT 12 2013/
A RATHER ACTIVE PATTERN OVER THE NEXT SEVEN DAYS. ABOVE NORMAL
TEMPS WILL CONTINUE TODAY... BUT WILL LIKELY BE TEMPERED A BIT BY
INCREASED CLOUDS AHEAD OF SHORTWAVE LIFTING INTO THE MID MS RIVER
VALLEY. THIS FEATURE HAD AIDED THUNDERSTORM DEVELOPMENT OVER
EASTERN OK EARLY THIS MORNING. CONVECTIVE POTENTIAL WILL SPREAD
INTO EASTER AR LATE THIS MORNING/EARLY AFTERNOON...WITH THE
SHORTWAVE PASSING BY TO THE NORTH. NAM BUFR SOUNDINGS FOR
JONESBORO DEPICTED SURFACE BASED CAPE AROUND 1500 J/KG AT 19Z...
ACCOMPANIED BY MODEST SHEAR. A FEW STORMS MAY CROSS THE RIVER INTO
WEST TN... BUT SHOULD WEAKEN AS THEY MOVE FURTHER INTO THE
MIDLEVEL RIDGE. BY THIS EVENING... THE SHORTWAVE WILL HAVE MOVED
WELL OFF THE NORTHEAST AND THE BOUNDARY LAYER WILL HAVE
STABILIZED. A SURFACE COLD FRONT WILL DROP INTO THE MIDSOUTH AND
STALL TONIGHT BEHIND THE EXITING MIDLEVEL SHORTWAVE. SLIGHTLY
DRIER AIR AND SHORTWAVE RIDGING SHOULD KEEP RAIN CHANCES AT BAY
FOR SUNDAY.
BY MONDAY AFTERNOON... THE FIRST IN A SERIES OF SHORTWAVES WILL
EJECT FROM A DEEP UPPER TROF CENTERED OVER CENTRAL ROCKIES. THIS
SHORTWAVE WILL ARRIVE OVER THE OZARKS MONDAY EVENING AS IT DEAMPLIFIES.
LOW LEVEL FLOW WILL VEER IN RESPONSE TO THE APPROACHING UPPER
LEVEL WAVE LATE MONDAY/EARLY TUESDAY...RETURNING MODIFIED GULF
AIR THE MIDSOUTH. GFS PROGS PRECIPITABLE WATER VALUES NEAR 1.9
INCHES BY TUESDAY AFTERNOON.
GFS AND ECMWF MODELS LIFT THE CENTER OF THE DEEP AND BROAD LONGWAVE
TROF FROM THE ROCKIES INTO THE CENTRAL PLAINS BY WEDNESDAY...
LOWERING HEIGHTS OVER MUCH OF CONUS. A SURFACE COLD FRONT WILL LAY OUT
NEARLY PARALLEL TO THE SOUTHWEST FLOW ALOFT...BEFORE DROPPING
THROUGH THE MIDSOUTH WITH A SHORTWAVE TROF PASSAGE LATE WEDNESDAY.
GIVEN THE PREFRONTAL MOISTURE PLUME AND COLD FRONTAL PASSAGE...
RAIN CHANCES APPEAR GOOD TUESDAY AND WEDNESDAY.
BY LATE WEDNESDAY... THE GFS AND ECMWF BEGIN TO PART WAYS. THE GFS
KEEPS A RIDGE WEST/TROF EAST PATTERN THROUGH THE WEEKEND...KEEPING THE
MIDSOUTH IN DRY NORTHWEST FLOW ALONG. CONVERSELY...THE ECMWF
DROPS SIGNIFICANT UPPER LEVEL ENERGY FROM WESTERN CANADA INTO THE
THE FOUR CORNERS REGION BY FRIDAY...THEN EJECTS AN OPEN BUT HIGHLY
AMPLIFIED TROF INTO THE CENTRAL AND SOUTHERN PLAINS BY LATE
SATURDAY. THE ECMWF SOLUTION WOULD RESULT IN POTENTIALLY ACTIVE
WEATHER ACROSS THE MIDSOUTH ON SATURDAY...A VERY DIFFERENT SOLUTION
THAN THAT OF THE GFS.
EXTENDED FORECAST PERIODS WERE HEAVILY WEIGHTED TOWARD THE ECMWF...
GIVEN THE ECMWF/S GREATER RECENT RUN TO RUN CONSISTENCY. WITH THE
LACK OF GFS CONCURRENCE...FORECAST CONFIDENCE IS BELOW AVERAGE
FOR THE LATE WEEK PERIODS.
PWB
&&
.AVIATION...
12Z TAF SET
PATCHY FOG IS OCCURRING AGAIN THIS MORNING AT KMKL REDUCING VSBYS
TO MVFR OR IFR AT TIMES. FOG WILL LIFT AFTER 13Z. SCT TSRAS WILL
DEVELOP TODAY ACROSS THE CWA AHEAD OF AN APPROACHING COLD FRONT.
WILL CONTINUE MENTION OF VCTS FOR NOW. EXPECT GENERALLY VFR
CONDITIONS UNLESS A TAF SITE IS AFFECTED BY A TSRA. AFTER
01Z...EXPECT TSRAS TO DIE OUT. NOT SURE ABOUT CLOUD COVER DURING
THE EVENING INTO THE OVERNIGHT HOURS. RAP INDICATES THERE COULD BE
SOME LOWER CIGS OCCUR DURING AT LEAST THE EVENING HOURS AND
CURRENTLY ON SATELLITE THERE IS SOME LOWER CIGS IN OKLAHOMA ALONG
FRONT. OTHER MODELS SCATTER CLOUDS OUT. FOR NOW WILL CONTINUE
WITH VFR CONDITIONS BUT WILL CHANGE FROM SCT040 SCT120 TO BKN040.
CAN/T RULE OUT SOME PATCHY FOG AT KMKL AGAIN LATE TONIGHT. LIGHT S
WINDS WILL BECOME NE THIS EVENING.
KRM
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 81 60 80 59 / 30 10 10 10
MKL 79 57 80 54 / 20 20 0 0
JBR 77 57 77 54 / 40 10 10 10
TUP 83 60 80 59 / 10 10 0 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
519 PM CDT SAT OCT 12 2013
.DISCUSSION...
253 PM CDT
SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON
WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER
AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW
BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON
WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE
NEXT WEEK.
REST OF TODAY AND TONIGHT...
THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO
CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY
EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG
THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND
IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS
SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM
COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING
INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS
POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER
SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL
UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT
AS THE SUN BREAKS OUT AGAIN.
LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING
AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN
DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT
LOWER THAN FORECAST.
SUNDAY AND MONDAY...
THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH
TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE
HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING
SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH
SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW.
WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S
TO AROUND 70 SOUTH.
TUESDAY AND WEDNESDAY...
AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE
NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN
RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN
MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW
CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND
SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A
SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS
AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL
BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE
EVALUATION.
THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS
BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED
WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET
SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW
IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO
CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT
LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A
FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE
OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT
JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500
J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF
1-1.5 INCHES.
THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH
ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS
THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE
SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW
WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT
CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE.
FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND
70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY
WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S.
EXTENDED...THURSDAY AND FRIDAY...
GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA
THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE
ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE
THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR
THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER
LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS
OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE
BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL
LOOKING COLD AS PREVIOUSLY ADVERTISED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* VFR CEILINGS SCATTERING OUT THIS NEXT HOUR.
* SOUTHWEST WINDS TURNING TO THE WEST THIS NEXT HOUR...WITH MID
TEEN GUSTS THROUGH EARLY EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT PROGRESSION HAS CONTINUED TO BE QUICKER THAN
INITIALLY THOUGHT...WHICH MEANS A SLIGHTLY EARLIER DEPARTURE OF
MVFR CLOUDS ALONG WITH THE WIND SHIFT TO WESTERLY. HAVE ADJUSTED
ACCORDINGLY QUICKER IN TAFS.
//PREV DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL
AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED
SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED
STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT
MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD.
WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY
45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS
SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO
SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW.
MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE
SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL
INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT
LAST LONG IF IT OCCURS.
AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW
AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO
LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND
MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE WITH CEILING TRENDS.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
MTF
&&
.MARINE...
300 PM CDT
A COLD FRONT TRAILING FROM LOW PRESSURE INCHES IN EASTERN
MANITOBA WILL MOVE EAST ACROSS LAKE MICHIGAN LATE THIS AFTERNOON
AND EARLY THIS EVENING SHIFTING WINDS TO OUT OF THE WEST AND
NORTHWEST. THE LOW CONTINUES NORTH-NORTHEASTWARD TO SOUTHWESTERN
HUDSON BAY TONIGHT AND HIGH PRESSURE MOVES NORTHEAST FROM THE
CENTRAL HIGH PLAINS TO IOWA. NORTHWEST AND NORTH WINDS WILL
DIMINISH SUNDAY AS THE HIGH CONTINUE TO THE NORTHEAST....REACHING
THE UPPER GREAT LAKES BY MONDAY MORNING. LOW PRESSURE TRACKS
NORTHEASTWARD FROM THE CENTRAL HIGH PLAINS TO IOWA MONDAY AND
MONDAY NIGHT. IN RESPONSE WINDS ON LAKE MICHIGAN WILL VEER TO OUT
OF THE EAST AND SOUTHEAST AND GRADUALLY INCREASE. THIS LOW WILL
MOVE ACROSS WISCONSIN AND CENTRAL LAKE MICHIGAN DURING TUESDAY
AND TUESDAY NIGHT...AND THEN ON ACROSS ONTARIO TO WESTERN QUEBEC
WEDNESDAY AND THURSDAY.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
301 PM CDT SAT OCT 12 2013
.DISCUSSION...
253 PM CDT
SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON
WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER
AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW
BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON
WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE
NEXT WEEK.
REST OF TODAY AND TONIGHT...
THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO
CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY
EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG
THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND
IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS
SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM
COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING
INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS
POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER
SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL
UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT
AS THE SUN BREAKS OUT AGAIN.
LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING
AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN
DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT
LOWER THAN FORECAST.
SUNDAY AND MONDAY...
THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH
TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE
HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING
SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH
SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW.
WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S
TO AROUND 70 SOUTH.
TUESDAY AND WEDNESDAY...
AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE
NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN
RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN
MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW
CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND
SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A
SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS
AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL
BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE
EVALUATION.
THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS
BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED
WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET
SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW
IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO
CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT
LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A
FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE
OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT
JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500
J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF
1-1.5 INCHES.
THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH
ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS
THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE
SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW
WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT
CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE.
FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND
70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY
WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S.
EXTENDED...THURSDAY AND FRIDAY...
GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA
THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE
ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE
THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR
THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER
LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS
OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE
BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL
LOOKING COLD AS PREVIOUSLY ADVERTISED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW
PRIOR TO 20Z.
* MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER
THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE.
* WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z.
* WINDS TURNING NE DURING SUNDAY AFTERNOON.
//DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL
AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED
SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED
STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT
MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD.
WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY
45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS
SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO
SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW.
MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE
SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL
INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT
LAST LONG IF IT OCCURS.
AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW
AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO
LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND
MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA
OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY.
* HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT
MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE
BRIEF /LIKELY UNDER ONE HOUR/.
* HIGH CONFIDENCE IN WSW WINDS BY 23Z.
* MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING
NE ON SUNDAY.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
MTF
&&
.MARINE...
300 PM CDT
A COLD FRONT TRAILING FROM LOW PRESSURE INCHES IN EASTERN
MANITOBA WILL MOVE EAST ACROSS LAKE MICHIGAN LATE THIS AFTERNOON
AND EARLY THIS EVENING SHIFTING WINDS TO OUT OF THE WEST AND
NORTHWEST. THE LOW CONTINUES NORTH-NORTHEASTWARD TO SOUTHWESTERN
HUDSON BAY TONIGHT AND HIGH PRESSURE MOVES NORTHEAST FROM THE
CENTRAL HIGH PLAINS TO IOWA. NORTHWEST AND NORTH WINDS WILL
DIMINISH SUNDAY AS THE HIGH CONTINUE TO THE NORTHEAST....REACHING
THE UPPER GREAT LAKES BY MONDAY MORNING. LOW PRESSURE TRACKS
NORTHEASTWARD FROM THE CENTRAL HIGH PLAINS TO IOWA MONDAY AND
MONDAY NIGHT. IN RESPONSE WINDS ON LAKE MICHIGAN WILL VEER TO OUT
OF THE EAST AND SOUTHEAST AND GRADUALLY INCREASE. THIS LOW WILL
MOVE ACROSS WISCONSIN AND CENTRAL LAKE MICHIGAN DURING TUESDAY
AND TUESDAY NIGHT...AND THEN ON ACROSS ONTARIO TO WESTERN QUEBEC
WEDNESDAY AND THURSDAY.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 PM CDT SAT OCT 12 2013
.DISCUSSION...
253 PM CDT
SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON
WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER
AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW
BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON
WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE
NEXT WEEK.
REST OF TODAY AND TONIGHT...
THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO
CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY
EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG
THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND
IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS
SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM
COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING
INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS
POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER
SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL
UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT
AS THE SUN BREAKS OUT AGAIN.
LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING
AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN
DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT
LOWER THAN FORECAST.
SUNDAY AND MONDAY...
THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH
TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE
HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING
SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH
SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW.
WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S
TO AROUND 70 SOUTH.
TUESDAY AND WEDNESDAY...
AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE
NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN
RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN
MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW
CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND
SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A
SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS
AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL
BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE
EVALUATION.
THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS
BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED
WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET
SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW
IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO
CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT
LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A
FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE
OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT
JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500
J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF
1-1.5 INCHES.
THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH
ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS
THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE
SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW
WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT
CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE.
FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND
70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY
WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S.
EXTENDED...THURSDAY AND FRIDAY...
GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA
THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE
ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE
THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR
THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER
LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS
OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE
BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL
LOOKING COLD AS PREVIOUSLY ADVERTISED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW
PRIOR TO 20Z.
* MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER
THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE.
* WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z.
* WINDS TURNING NE DURING SUNDAY AFTERNOON.
//DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL
AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED
SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED
STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT
MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD.
WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY
45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS
SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO
SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW.
MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE
SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL
INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT
LAST LONG IF IT OCCURS.
AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW
AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO
LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND
MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA
OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY.
* HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT
MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE
BRIEF /LIKELY UNDER ONE HOUR/.
* HIGH CONFIDENCE IN WSW WINDS BY 23Z.
* MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING
NE ON SUNDAY.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
MTF
&&
.MARINE...
125 AM CDT
DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH
DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS
FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE
PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE
NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE
20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH
30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD
FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS
AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND
EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL
MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY
THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE
WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY
NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS
QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS
AS THE RIDGE APPROACHES.
THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY
NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS
THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER
BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE
NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE
CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS
DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT
WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN
WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN
FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE
TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1248 PM CDT SAT OCT 12 2013
.DISCUSSION...
1015 AM CDT
MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES
HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST
MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID
70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY
IN THE UPPER 60S.
THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES
TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND
THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY
DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY
ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS
WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE
TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN
SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED
SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES
SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON
THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED
CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW
HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM
850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF
ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE
FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN
THE SLIGHT CHANCE OF THUNDER.
TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH
FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT
HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL
LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS
THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH
FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST
AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO
THE SCATTERED SHOWER ARRIVAL.
MTF
//PREV DISCUSSION...
256 AM CDT
TODAY...
THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY
LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING
AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE
IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN
KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER
SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN
IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE
SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET
OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE
FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS
SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR
ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING.
MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID
AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA.
GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60
DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT
RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE
REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE
NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED
VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY
WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS
MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT
BEHIND.
TONIGHT THROUGH MONDAY NIGHT...
PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH
PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD
ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY
DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS
PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE
ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND
CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE
30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP
TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA.
FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO
MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES
WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE
WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO
INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH
DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST
RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT
RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY
NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN...
EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS
COOLER SIDE OF GUIDANCE.
TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT
EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER
SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID
LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT
RANGE TO THE MID MISSOURI VALLEY.
TUESDAY THROUGH FRIDAY...
STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING
WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH
A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL
MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED
SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK
DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY
SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD
TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE
TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE
LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND
MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY.
PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO
END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A
BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A
PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD
AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C//
WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A
PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS
LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL
TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW
PRIOR TO 20Z.
* MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER
THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE.
* WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z.
* WINDS TURNING NE DURING SUNDAY AFTERNOON.
//DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL
AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED
SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED
STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT
MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD.
WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY
45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS
SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO
SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW.
MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE
SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL
INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT
LAST LONG IF IT OCCURS.
AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW
AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO
LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND
MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA
OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY.
* HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT
MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE
BRIEF /LIKELY UNDER ONE HOUR/.
* HIGH CONFIDENCE IN WSW WINDS BY 23Z.
* MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING
NE ON SUNDAY.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
MTF
&&
.MARINE...
125 AM CDT
DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH
DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS
FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE
PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE
NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE
20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH
30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD
FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS
AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND
EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL
MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY
THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE
WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY
NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS
QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS
AS THE RIDGE APPROACHES.
THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY
NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS
THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER
BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE
NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE
CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS
DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT
WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN
WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN
FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE
TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1107 AM CDT SAT OCT 12 2013
.DISCUSSION...
1015 AM CDT
MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES
HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST
MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID
70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY
IN THE UPPER 60S.
THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES
TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND
THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY
DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY
ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS
WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE
TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN
SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED
SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES
SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON
THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED
CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW
HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM
850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF
ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE
FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN
THE SLIGHT CHANCE OF THUNDER.
TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH
FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT
HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL
LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS
THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH
FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST
AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO
THE SCATTERED SHOWER ARRIVAL.
MTF
//PREV DISCUSSION...
256 AM CDT
TODAY...
THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY
LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING
AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE
IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN
KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER
SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN
IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE
SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET
OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE
FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS
SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR
ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING.
MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID
AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA.
GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60
DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT
RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE
REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE
NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED
VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY
WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS
MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT
BEHIND.
TONIGHT THROUGH MONDAY NIGHT...
PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH
PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD
ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY
DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS
PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE
ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND
CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE
30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP
TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA.
FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO
MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES
WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE
WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO
INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH
DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST
RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT
RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY
NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN...
EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS
COOLER SIDE OF GUIDANCE.
TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT
EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER
SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID
LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT
RANGE TO THE MID MISSOURI VALLEY.
TUESDAY THROUGH FRIDAY...
STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING
WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH
A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL
MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED
SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK
DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY
SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD
TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE
TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE
LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND
MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY.
PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO
END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A
BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A
PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD
AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C//
WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A
PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS
LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL
TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SCATTERED SHOWERS FROM 1730Z-2000Z WITH A CHANCE FOR ISOLATED
THUNDER.
* A LIKELY 2-3 HOUR PERIOD OF 1700-2500 FT CIGS BEHIND THE
SHOWERS DURING THE MID TO LATE AFTERNOON.
* WIND SHIFT FROM S TO WSW LATE THIS AFTERNOON WITH COLD FRONTAL
PASSAGE. A SHIFT TO NORTHERLY IS EXPECTED SUNDAY MORNING.
MDB/MTF
//DISCUSSION...UPDATED 12Z...
STRONG LOW PRESSURE IS MOVING NORTH-NORTHEAST ACROSS FAR SOUTHEAST
MANITOBA HAS A COLD FRONTAL BOUNDARY STRETCHING SOUTHWARD FROM IT
WHICH IS JUST NOW REACHING THE MISSISSIPPI RIVER NEAR THE QUAD
CITIES. SEVERAL WEAK WAVES APPEAR TO BE EMBEDDED IN THE UPPER
FLOW PATTERN. A NARROW BAND OF SHOWERS HAS DEVELOPED OUT AHEAD OF
THE FRONT IN CONJUNCTION WITH THE ACTIVE UPPER FLOW. THE EASTWARD
PUSH OF THIS BAND HAS BEEN SLOW BUT IT LOOKS TO CONTINUE THROUGH
THE MORNING. THE FRONT WILL TRY TO CATCH UP TO THE UPPER FORCING
THROUGH THE DAY SO ANY GAP BETWEEN THE CURRENT ACTIVITY NEAR RFD
AND ACTIVITY NEAR THE FRONT TO THE WEST MAY CLOSE WITH TIME. WILL
CONTINUE WITH A FEW HOURS OF TEMPO SHOWERS ACROSS THE TERMINALS
INTO THE AFTERNOON. STILL CANNOT RULE OUT THUNDER BUT THUNDER
COVERAGE LOOKS TO BE ISOLATED OVER THE AREA WITH THE THREAT TOO
LOW TO MENTION IN THE TAFS AT THIS TIME. BRIEF MVFR CIGS MAY
ACCOMPANY THE FRONTAL PASSAGE BUT THESE LOOKS TO BE SHORT LIVED SO
WILL CARRY PREVAILING LOWER END VFR CLOUD COVER.
SOUTH-SOUTHEAST WINDS WILL INCREASE IN SPEED WITH TIME THIS
MORNING AND TURN MORE SOUTH OR EVEN SOUTH-SOUTHWEST BEFORE TURNING
SOUTHWEST THEN WEST WITH THE APPROACH AND PASSAGE OF THE FRONT
THROUGH THE AFTERNOON. SPEEDS WILL EASE UP OVERNIGHT AS HIGH
PRESSURE ARRIVES KEEPING QUIET WEATHER IN PLACE. WINDS WILL THEN
TURN MORE NORTHERLY SUNDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN SCATTERED SHOWERS WITH ISOLATED THUNDER IN
THE AREA THROUGH 20Z.
* MEDIUM CONFIDENCE IF MVFR CIGS TIMING AFTER THE SHOWERS BUT LOW
CONFIDENCE IN THEM STAYING ABOVE 1500 FT.
* HIGH CONFIDENCE IN WIND TRENDS.
MDB/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...VFR.
TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE.
WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR.
FRIDAY...VFR.
&&
.MARINE...
125 AM CDT
DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH
DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS
FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE
PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE
NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE
20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH
30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD
FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS
AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND
EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL
MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY
THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE
WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY
NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS
QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS
AS THE RIDGE APPROACHES.
THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY
NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS
THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER
BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE
NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE
CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS
DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT
WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN
WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN
FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE
TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
605 PM EDT SAT OCT 12 2013
.SYNOPSIS...
ISSUED AT 604 PM EDT SAT OCT 12 2013
A WEAKENING COLD FRONT WILL MOVE EAST ACROSS THE AREA
TONIGHT...BRINGING A CHANCE FOR SCATTERED SHOWERS AND PERHAPS AN
ISOLATED THUNDERSTORM. MANY LOCATIONS MAY REMAIN DRY THOUGH. HIGH
PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY WITH COOLER
TEMPERATURES AND DRY WEATHER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 350 PM EDT SAT OCT 12 2013
LEAD UPPER LEVEL SHORT WAVE ENTERING NORTHWEST ILLINOIS THIS
AFTERNOON WILL CONTINUE TO LIFT NORTHEAST THROUGH THE WESTERN
GREAT LAKES REGION THIS EVENING. SOUTHERN FRINGE OF DPVA ZONE WITH
THIS VORT MAX AND PROXIMITY TO RIGHT ENTRANCE REGION OF WESTERN
GREAT LAKES UPPER JET STREAK SHOULD SUPPORT SCT SHOWER DEVELOPMENT
INTO NORTHWEST INDIANA/SOUTHWEST LOWER MICHIGAN OVER THE NEXT
SEVERAL HOURS. A PREFRONTAL BAND OF SHOWERS LIKELY ASSOCIATED WITH
NARROW ZONE OF STRONG LOW LEVEL THETAE ADVECTION HAS BEEN
DIMINISHING IN COVERAGE THROUGH THE AFTERNOON...BUT COULD BE
ENOUGH FORCING FOR ISOLATED/SCATTERED SHOWERS OVER NEXT FEW HOURS
ACROSS EXTREME NORTHWEST PORTIONS OF THE AREA. SHEARING NATURE TO
NORTHERN ILLINOIS SHORT WAVE AS IT LIFTS NORTHEAST SHOULD LEAD TO
EVENTUAL WEAKENING OF LOW LEVEL FRONTOGENESIS FORCING FROM WEST TO
EAST ACROSS THE AREA OVERNIGHT AS COLD FRONT MOVES THROUGH. ALONG
WITH THIS WEAKENING CONVERGENCE...SHORT TERM MODEL GUIDANCE IS IN
GOOD AGREEMENT IN PWATS DIMINISHING INTO THE 1.25 RANGE AS THIS
MOISTURE AXIS SHIFTS INTO FAR EASTERN PORTIONS OF THE FORECAST
AREA OVERNIGHT. BASED ON RECENT TRENDS AND STRONGEST MID/UPPER
FORCING SHIFTING NORTH OF THE AREA...GREATEST PRECIP COVERAGE
SHOULD REMAIN TO THE NORTH AND HAVE LOWERED POPS INTO THE LOW TO
MID CHANCE RANGE...AND THIS TREND MAY NEED TO BE CONTINUED THIS
EVENING. HAVE MADE NO CHANGE TO PREVIOUS FORECAST IN REGARDS TO
DIMINISHING POPS FROM WEST TO EAST TONIGHT WITH CONTINUED
WEAKENING OF LOW/MID LEVEL FRONTOGENESIS FORCING AND WANING
MID/UPPER LEVEL FORCING. 18Z RUC ANALYSIS DEPICTS AXIS OF 250-500
J/KG MUCAPES TRACKING INTO NORTHWEST INDIANA THIS AFTERNOON IN
ASSOCIATION WITH THIS LOW LEVEL MOISTURE AXIS...WHICH COMBINED
WITH SOUTHERN TAIL OF STRONGER UPPER FORCING COULD BE ENOUGH FOR
AN ISOLD TSRA ACROSS ESPECIALLY THE WESTERN HALF OF THE AREA THIS
EVENING. DID MAINTAIN SOME SLIGHT CHANCE -RW POPS ACROSS THE FAR
SOUTHEAST INTO SUNDAY MORNING WITH SOME SIGNAL IN MODEL GUIDANCE
OF LINGERING WEAK MID LEVEL FRONTOGENESIS POSSIBLY SUSTAINING A
FEW LIGHT RAIN SHOWERS. STRONG LOW LEVEL CAA TO OVERSPREAD THE
AREA LATE TONIGHT INTO SUNDAY MORNING WITH COOLER CONDITIONS FROM
THE MID 60S NORTHWEST TO AROUND 70 SOUTHEAST SUNDAY AFTERNOON.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM EDT SAT OCT 12 2013
HIGH PRESSURE WILL KEEP THE AREA HIGH AND DRY AS YET ANOTHER WAVE
ROUNDS THE WEST COAST TROUGH AND TAKES AIM ON THE REGION. MODELS
CONTINUE TO VARY ON TIMING/SPEED OF EJECTION OF THIS FEATURE WITH
12Z GEM SLOWER VS 12Z GFS. ECMWF IS FLIP-FLOPPING SOLUTIONS WITH NEW
12Z RUN VERY SIMILAR IN SPEED/LOCATION TO 12Z GFS. CONFIDENCE HIGH
ENOUGH IN SLOWING DOWN ARRIVAL ON TUESDAY TO BACK OFF POPS IN THE
EAST...BUT TO INCREASE TO LOW END LIKELY TUESDAY NIGHT WHICH HAS
BEEN CONSISTENTLY THE MOST FAVORED PERIOD. BEYOND THIS...TIMING
ISSUES ALREADY NOTED WITH TROUGH WARRANTS HOLDING ONTO SLGT CHC/CHC
POPS WEDS/WEDS WITH HIGHEST EAST WHERE FRONTAL BOUNDARY MAY LINGER
LONGER.
COLDER AIR ARRIVES BEHIND THE SYSTEM WITH MODELS AGREEING TO SOME
EXTENT ON 850 MB TEMPS DROPPING TO AROUND 0 C. AS A RESULT...BELOW
NORMAL TEMPS IN THE 50S WILL SETTLE IN AND PERSIST THROUGH SATURDAY.
LAKE ENHANCED SHOWERS WILL BE POSSIBLE AT TIMES THURS INTO FRI AS
WEAK WAVES ROTATE THROUGH TO CONTRIBUTE MSTR...LIFT AND SOMEWHAT
MORE FAVORABLE INVERSION HGTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 350 PM EDT SAT OCT 12 2013
A STRONG UPPER VORT MAX ACROSS NORTHERN IOWA/MINNESOTA WILL
CONTINUE TO TRACK INTO THE WESTERN GREAT LAKES THIS EVENING. THE
APPROACH OF THIS SHORT WAVE HAS LED TO AN INCREASE IN THE COVERAGE
OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL
ILLINOIS. ANOTHER AREA OF PREFRONTAL SHOWERS CONTINUES TO LIFT
NORTHEAST ACROSS EAST CENTRAL ILLINOIS. CONFIDENCE IS SOMEWHAT LOW
IN REGARDS TO PRECIP COVERAGE FOR TERMINALS GIVEN AFOREMENTIONED
IOWA VORT MAX WILL BE LIFTING NORTHEAST THIS AFTERNOON WITH
WEAKENING CONVERGENCE ALONG THE COLD FRONT THIS EVENING. WILL
CARRY TEMPO -SHRA IN THE 22Z-02Z TIMEFRAME WITH MVFR CIGS POSSIBLE
IN ASSOCIATION WITH POOLED MOISTURE ALONG THE FRONT. WEAKENING
FRONTAL CONVERGENCE WITH EASTWARD EXTENT LENDS EVEN LOWER
CONFIDENCE TO SHRA COVERAGE AT KFWA WHERE HAVE LIMITED MENTION TO
VCSH TONIGHT. AN ISOLATED TSRA IS POSSIBLE AT KSBN...ALTHOUGH WITH
EARLY EVENING FRONTAL TIMING AND LOSS OF PEAK INSTABILITY WILL
CONTINUE TO OMIT WITH 18Z TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...CEO
SHORT TERM...MARSILI
LONG TERM...FISHER
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
356 PM EDT SAT OCT 12 2013
.SYNOPSIS...
ISSUED AT 1213 PM EDT SAT OCT 12 2013
AN UPPER LEVEL DISTURBANCE TRACKING ACROSS THE WESTERN GREAT LAKES
REGION TONIGHT WILL ALLOW A COLD FRONT TO TRACK FROM WEST TO EAST
ACROSS THE AREA. SCATTERED SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT TONIGHT. A RETURN TO
SOMEWHAT COOLER CONDITIONS IS THEN EXPECTED FOR THE EARLY PORTIONS
OF NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 350 PM EDT SAT OCT 12 2013
LEAD UPPER LEVEL SHORT WAVE ENTERING NORTHWEST ILLINOIS THIS
AFTERNOON WILL CONTINUE TO LIFT NORTHEAST THROUGH THE WESTERN
GREAT LAKES REGION THIS EVENING. SOUTHERN FRINGE OF DPVA ZONE WITH
THIS VORT MAX AND PROXIMITY TO RIGHT ENTRANCE REGION OF WESTERN
GREAT LAKES UPPER JET STREAK SHOULD SUPPORT SCT SHOWER DEVELOPMENT
INTO NORTHWEST INDIANA/SOUTHWEST LOWER MICHIGAN OVER THE NEXT
SEVERAL HOURS. A PREFRONTAL BAND OF SHOWERS LIKELY ASSOCIATED WITH
NARROW ZONE OF STRONG LOW LEVEL THETAE ADVECTION HAS BEEN
DIMINISHING IN COVERAGE THROUGH THE AFTERNOON...BUT COULD BE
ENOUGH FORCING FOR ISOLATED/SCATTERED SHOWERS OVER NEXT FEW HOURS
ACROSS EXTREME NORTHWEST PORTIONS OF THE AREA. SHEARING NATURE TO
NORTHERN ILLINOIS SHORT WAVE AS IT LIFTS NORTHEAST SHOULD LEAD TO
EVENTUAL WEAKENING OF LOW LEVEL FRONTOGENESIS FORCING FROM WEST TO
EAST ACROSS THE AREA OVERNIGHT AS COLD FRONT MOVES THROUGH. ALONG
WITH THIS WEAKENING CONVERGENCE...SHORT TERM MODEL GUIDANCE IS IN
GOOD AGREEMENT IN PWATS DIMINISHING INTO THE 1.25 RANGE AS THIS
MOISTURE AXIS SHIFTS INTO FAR EASTERN PORTIONS OF THE FORECAST
AREA OVERNIGHT. BASED ON RECENT TRENDS AND STRONGEST MID/UPPER
FORCING SHIFTING NORTH OF THE AREA...GREATEST PRECIP COVERAGE
SHOULD REMAIN TO THE NORTH AND HAVE LOWERED POPS INTO THE LOW TO
MID CHANCE RANGE...AND THIS TREND MAY NEED TO BE CONTINUED THIS
EVENING. HAVE MADE NO CHANGE TO PREVIOUS FORECAST IN REGARDS TO
DIMINISHING POPS FROM WEST TO EAST TONIGHT WITH CONTINUED
WEAKENING OF LOW/MID LEVEL FRONTOGENESIS FORCING AND WANING
MID/UPPER LEVEL FORCING. 18Z RUC ANALYSIS DEPICTS AXIS OF 250-500
J/KG MUCAPES TRACKING INTO NORTHWEST INDIANA THIS AFTERNOON IN
ASSOCIATION WITH THIS LOW LEVEL MOISTURE AXIS...WHICH COMBINED
WITH SOUTHERN TAIL OF STRONGER UPPER FORCING COULD BE ENOUGH FOR
AN ISOLD TSRA ACROSS ESPECIALLY THE WESTERN HALF OF THE AREA THIS
EVENING. DID MAINTAIN SOME SLIGHT CHANCE -RW POPS ACROSS THE FAR
SOUTHEAST INTO SUNDAY MORNING WITH SOME SIGNAL IN MODEL GUIDANCE
OF LINGERING WEAK MID LEVEL FRONTOGENESIS POSSIBLY SUSTAINING A
FEW LIGHT RAIN SHOWERS. STRONG LOW LEVEL CAA TO OVERSPREAD THE
AREA LATE TONIGHT INTO SUNDAY MORNING WITH COOLER CONDITIONS FROM
THE MID 60S NORTHWEST TO AROUND 70 SOUTHEAST SUNDAY AFTERNOON.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM EDT SAT OCT 12 2013
HIGH PRESSURE WILL KEEP THE AREA HIGH AND DRY AS YET ANOTHER WAVE
ROUNDS THE WEST COAST TROUGH AND TAKES AIM ON THE REGION. MODELS
CONTINUE TO VARY ON TIMING/SPEED OF EJECTION OF THIS FEATURE WITH
12Z GEM SLOWER VS 12Z GFS. ECMWF IS FLIP-FLOPPING SOLUTIONS WITH NEW
12Z RUN VERY SIMILAR IN SPEED/LOCATION TO 12Z GFS. CONFIDENCE HIGH
ENOUGH IN SLOWING DOWN ARRIVAL ON TUESDAY TO BACK OFF POPS IN THE
EAST...BUT TO INCREASE TO LOW END LIKELY TUESDAY NIGHT WHICH HAS
BEEN CONSISTENTLY THE MOST FAVORED PERIOD. BEYOND THIS...TIMING
ISSUES ALREADY NOTED WITH TROUGH WARRANTS HOLDING ONTO SLGT CHC/CHC
POPS WEDS/WEDS WITH HIGHEST EAST WHERE FRONTAL BOUNDARY MAY LINGER
LONGER.
COLDER AIR ARRIVES BEHIND THE SYSTEM WITH MODELS AGREEING TO SOME
EXTENT ON 850 MB TEMPS DROPPING TO AROUND 0 C. AS A RESULT...BELOW
NORMAL TEMPS IN THE 50S WILL SETTLE IN AND PERSIST THROUGH SATURDAY.
LAKE ENHANCED SHOWERS WILL BE POSSIBLE AT TIMES THURS INTO FRI AS
WEAK WAVES ROTATE THROUGH TO CONTRIBUTE MSTR...LIFT AND SOMEWHAT
MORE FAVORABLE INVERSION HGTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 350 PM EDT SAT OCT 12 2013
A STRONG UPPER VORT MAX ACROSS NORTHERN IOWA/MINNESOTA WILL
CONTINUE TO TRACK INTO THE WESTERN GREAT LAKES THIS EVENING. THE
APPROACH OF THIS SHORT WAVE HAS LED TO AN INCREASE IN THE COVERAGE
OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL
ILLINOIS. ANOTHER AREA OF PREFRONTAL SHOWERS CONTINUES TO LIFT
NORTHEAST ACROSS EAST CENTRAL ILLINOIS. CONFIDENCE IS SOMEWHAT LOW
IN REGARDS TO PRECIP COVERAGE FOR TERMINALS GIVEN AFOREMENTIONED
IOWA VORT MAX WILL BE LIFTING NORTHEAST THIS AFTERNOON WITH
WEAKENING CONVERGENCE ALONG THE COLD FRONT THIS EVENING. WILL
CARRY TEMPO -SHRA IN THE 22Z-02Z TIMEFRAME WITH MVFR CIGS POSSIBLE
IN ASSOCIATION WITH POOLED MOISTURE ALONG THE FRONT. WEAKENING
FRONTAL CONVERGENCE WITH EASTWARD EXTENT LENDS EVEN LOWER
CONFIDENCE TO SHRA COVERAGE AT KFWA WHERE HAVE LIMITED MENTION TO
VCSH TONIGHT. AN ISOLATED TSRA IS POSSIBLE AT KSBN...ALTHOUGH WITH
EARLY EVENING FRONTAL TIMING AND LOSS OF PEAK INSTABILITY WILL
CONTINUE TO OMIT WITH 18Z TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...FISHER
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
234 PM EDT SAT OCT 12 2013
.UPDATE...
ISSUED AT 230 PM EDT SAT OCT 12 2013
HOURLY GRIDS WERE UPDATED BASED ON RECENT SATELLITE AND OBSERVATION
TRENDS. THE STRATUS AND STRATOCU OVER THE EASTERN CWA HAS GRADUALLY
BEEN ERODING WITH CU DEVELOPING TO ITS WEST. THIS TREND SHOULD
CONTINUE OVER THE NEXT FEW HOURS WITH CU AND STRATOCU TENDING TO
DISSIPATE DURING THE EVENING.
UPDATE ISSUED AT 1122 AM EDT SAT OCT 12 2013
STRATUS AROUND THE WESTERN EDGE OF THE EAST COAST CLOSED LOW HAS
ADVECTED ABOUT A THIRD TO A HALF OF THE WAY WEST ACROSS THE CWA THIS
MORNING. THE WESTERN EDGE OF THIS IS NEAR THE KY HIGHWAY 15 CORRIDOR
IN EASTERN KY. DAYTIME HEATING MAY TEND TO WHITTLE AWAY AT THE
WESTERN TO SOUTHWESTERN EDGE OF THIS...BUT SUFFICIENT MOISTURE IS ALSO
IN PLACE FOR SOME PANCAKE CU TO THE WEST OF THIS. THE STRATUS SHOULD
BECOME MORE STRATOCU AND CU IN NATURE AS THE AFTERNOON PROGRESSES AND
MIX OUT TO AN EXTENT. THE TUG VALLEY NEAR THE WV BORDER APPEARS TO BE
DESTINED TO BE CLOUDY THE LONGEST.
THE CLOUD COVER WILL AFFECT DAYTIME HIGHS AND THEY HAVE BEEN ADJUSTED
DOWNWARD ACCORDINGLY A FEW DEGREES IN THE EASTERN HALF OF THE
CWA...ESPECIALLY NEAR THE WV BORDER.
UPDATE ISSUED AT 758 AM EDT SAT OCT 12 2013
LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST.
THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN
TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE
UPDATED FORECAST GRIDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM EDT SAT OCT 12 2013
A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR
DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR
EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT.
WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS
TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE
EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS
COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE
WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE
LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY
THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE
CAPPED BELOW THE -20C LEVEL.
WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN
TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS
WHERE CLOUDS ARE MORE SIGNIFICANT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 413 AM EDT SAT OCT 12 2013
BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD
AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE
APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND
A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE
LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT
WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT
WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY
SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED
FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY.
LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS
CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN
AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN
KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS
MONDAY TO ACCOUNT FOR THIS.
SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG
500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE
SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE
LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE
GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN
SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS
TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH
MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN
MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES
KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH
THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME
PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO
THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE
FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT
PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON
ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO
MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD
FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 225 PM EDT SAT OCT 12 2013
THE STRATUS AND STRATOCU EAST AND SOUTHEAST OF JKL CONTINUES TO LIFT
AND MIXOUT THOUGH IFR IS POSSIBLE AT SJS FOR THE NEXT COUPLE OF
HOURS. OTHERWISE...CU IN THE VFR RANGE SHOULD DEVELOP FURTHER WEST
NEAR JKL...LOZ AND SME WITH THIS TENDING TO DISSIPATE AFTER 21Z. SOME
CLOUDS MAY LINGER IN THE LOWER END OF THE VFR RANGE OVERNIGHT...ESPECIALLY
FROM JKL SOUTHEAST AND EAST. HOWEVER...VALLEY FOG SHOULD DEVELOP
AGAIN AROUND 6Z...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE
EASTERN PART OF THE AREA. THIS COULD SET THE STAGE FOR FOG WITH VIS
DOWN TO AIRPORT MINS OR BELOW BETWEEN 8Z AND 13Z AT LOZ AND SME AND
OTHER LOCATIONS IN THE SOUTHWEST CWA. OTHERWISE...SOME CU NEAR 5KFT
AND SOME ISOLATED SHOWERS MAY DEVELOP LATE IN THE PERIOD AS A COLD
FRONT AND UPPER LEVEL DISTURBANCE APPROACH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...JP
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1238 PM CDT SAT OCT 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING
INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN
AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT
FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15.
THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH
TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL.
ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL
FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH
A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM
NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS
TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT
SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL
15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP
MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS
OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL
MN TODAY.
TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK
THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS
BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES
IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH
COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH
30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL
COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE
GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND
THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS
FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP
THEIR FIRST 32 OR COLDER LOW THIS SEASON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CDT SAT OCT 12 2013
SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH
PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW
AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS
RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE
FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS
TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW
REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST
FOUR NIGHTS IS BEST WITH THE ECMWF. THIS SOLUTION RECEIVED THE
MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN
AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL
LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING
I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI
MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN
WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE
TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE
FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A
THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH
CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS.
RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY
SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL
KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT
RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE
LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT
LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH
THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF
THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF
CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE
COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH...
STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME...
THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY
WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN
PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW
ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE
UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT-
OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM
LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED
NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1227 PM CDT SAT OCT 12 2013
MVFR CONDS OVER THE NORTHERN CWA THIS AFTERNOON...WITH ISOLD IFR
CONDITIONS AS COLD CORE TROUGH LIFTS NORTHEAST THIS AFTERNOON. THIS
WILL AFFECT MAINLY KAXN/KSTC. THE REST OF THE AREA WILL SEE SOME
VFR CIGS 3-4K FEET. THEN CLEARING INTO THE EVENING. WEST/NORTHWEST
WINDS SUSTAINED 15-25 WITH SOME GUSTS AROUND 30 KTS AT TIMES.
EXPECT WINDS TO DIMINISH AS TROUGH EXITS TO THE NORTHEAST. WITH
SURFACE RIDGE MOVING INTO THE WEST SHOULD SEE LIGHT WEST WINDS
LESS THAN 10 KTS INTO SUNDAY.
KMSP...CIGS AROUND 3-4K FEET THROUGH THE AFTERNOON SHOULD CLEAR
INTO THE EVENING. SOME SPRINKLES ASSOCIATED WITH UPPER TROUGH TO
THE WEST...BUT FEEL THEY WILL LIFT OFF TO THE NORTH THROUGH THE
AFTERNOON. SURFACE WINDS SOUTHWEST TO WEST THIS AFTERNOON AND
GUSTY. THEY SHOULD DIMINISH THIS EVENING AND BE LIGHT WEST INTO SUNDAY.
/OUTLOOK FOR KMSP/
MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS.
TUE...MVFR/IFR WITH SHRA. WINDS NE 5 KTS.
WED...MVFR. CHANCE SHRA. WINDS NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 PM CDT SAT OCT 12 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 341 PM CDT SAT OCT 12 2013
AT 3 PM...THE COLD FRONT...WHICH BROUGHT ISOLATED TO SCATTERED
SHOWERS TO THE AREA OVERNIGHT...WAS JUST MOVING INTO LAKE MICHIGAN.
THIS FRONT BECAME MORE ACTIVE AS IT RAN INTO DEEPER MOISTURE EAST
OF THE FORECAST AREA. WATER VAPOR IMAGERY SHOWS A VORT MAX MOVING
THROUGH CENTRAL MINNESOTA. THIS SYSTEM WAS PRODUCING AN AREA OF
SHOWERS ACROSS EAST CENTRAL MINNESOTA AND CLOUDS ACROSS THE
NORTHERN TWO-THIRDS OF MINNESOTA AND IN WEST-CENTRAL AND NORTHWEST
WISCONSIN. WITH THE LOSS OF DIURNAL HEATING...THE HRRR CONTINUES TO
SHOW THAT THE SHOWERS WILL RAPIDLY DISSIPATE AS THEY MOVE EAST
INTO WISCONSIN THIS EVENING. WITH AN OPEN CELLULAR STRUCTURE TO
THE CLOUDS ACROSS SOUTHEAST MINNESOTA AND WEST CENTRAL
WISCONSIN...EXPECT THE CLOUDS TO ALL DISSIPATE WITH THE LOSS OF
DIURNAL HEATING THIS EVENING.
AFTER MIDNIGHT TONIGHT...THE MAIN CONCERN WILL BE WHETHER FROST
WILL DEVELOP OR NOT. IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA...
THE BUFKIT SOUNDINGS SHOW THE LOWEST 1 KM WILL HAVE THE WINDS DROP
OFF INTO THE 5 TO 10 KNOT RANGE. HOWEVER THE NOCTURNAL BOUNDARY
LAYER REMAINS VERY DRY. AS A RESULT...ONLY EXPECTING PATCHY FROST
IN THESE AREAS. MEANWHILE IN CENTRAL AND NORTH-CENTRAL WISCONSIN...
THE BOUNDARY LAYER IS VERY SHALLOW ONLY A COUPLE 100 FEET.
MEANWHILE THE WINDS ALOFT REMAIN IN THE 10 TO 15 KNOT RANGE. WHILE
THE WINDS ARE NOT OVERLY FAVORABLE...THERE IS MORE MOISTURE IN THE
LOWEST LAYERS. LIKE IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA...IT
LOOKS LIKE THE FROST WILL BE PATCHY TO SCATTERED. WITH NO AREAS OF
WIDESPREAD FROST...THE CONSENSUS WAS NOT ISSUE A FROST ADVISORY.
ON SUNDAY...A 1029 MB SURFACE HIGH WILL MOVE EAST ACROSS THE AREA.
THIS HIGH PROVIDE SUNNY SKIES ACROSS THE REGION. BUFKIT SOUNDINGS
SUGGEST THAT THE AREA WILL MIX TO AROUND 875 MB DURING THE
AFTERNOON. WITH TEMPERATURES AT THIS LEVEL RANGING FROM 2 TO 5C...
HIGH TEMPERATURES WILL LIKELY TOP OUT AROUND 60 DEGREES. THIS IS
VERY CLOSE TO THE NORMAL HIGH FOR MID-OCTOBER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 341 PM CDT SAT OCT 12 2013
ON SUNDAY NIGHT...A DEEP LAYER OF LIGHT WINDS REMAINS ACROSS
CENTRAL AND NORTH-CENTRAL WISCONSIN. IN ADDITION SKIES WILL REMAIN
MOSTLY CLEAR. THIS WILL ALLOW TEMPERATURES TO FALL INTO THE LOWER
AND MID 30S ALONG AND NORTH OF INTERSTATE 94. THESE TEMPERATURES
WILL BE COLD ENOUGH FOR SOME FROST TO DEVELOP. THE COVERAGE LOOKS
TO BE MUCH MORE WIDESPREAD THAN TONIGHT. IF THIS CONTINUES...WILL
LIKELY HAVE TO ISSUE A FROST ADVISORY.
FROM MONDAY NIGHT INTO TUESDAY...THE 12.12Z MODELS CONTINUE TO
SHOW THAT A TROUGH WILL MOVE NORTHEAST TOWARD THE FORECAST AREA.
WHILE THEY CONTINUE TO BE IN GOOD AGREEMENT WITH THIS OCCURRING...
MODELS HAVE CONTINUED TO SLOW ITS MOVEMENT INTO THE AREA. DURING
THE EVENING...MODERATE TO STRONG 850 MB MOISTURE TRANSPORT AND STRONG
SYNOPTIC FORCING DEVELOPS WEST OF THE MISSISSIPPI RIVER. AS THIS
OCCURS...EXPECT THE RAPID DEVELOPMENT OF SHOWERS. MEANWHILE THE
COMBINATION OF DRY AIR AND WEAK FORCING WILL KEEP MUCH OF WESTERN
WISCONSIN DRY. FROM LATE MONDAY NIGHT INTO TUESDAY...THE AREA
WILL SEE MODERATE MOISTURE TRANSPORT AND STRONG SYNOPTIC FORCING.
AS A RESULT EXPECT THE RAIN TO CONTINUE THROUGH MUCH OF THIS TIME
PERIOD. HOWEVER AS THE LOW MOVES OFF TO THE NORTHEAST...THERE ARE
SOME INDICATIONS THAT DRY SLOT MAY MOVE INTO NORTHEAST IOWA
DURING THE MID TO LATE AFTERNOON. IF THIS OCCUR...THERE WOULD
LIKELY BE A DECREASE IN PRECIPITATION CHANCES IN THIS AREA.
FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT...THE MAIN QUESTION CONTINUES
TO BE WHERE WILL THE DEFORMATION BAND WILL BE LOCATED AND HOW FAST
WILL IT MOVE NORTHEAST OUT OF THE AREA. LIKE THEIR
PREDECESSORS...THE 12.12Z MODELS CONTINUE TO STRUGGLE WITH ITS
LOCATION AND TIMING. DUE TO THIS...KEPT PRECIPITATION CHANCES
RANGING FROM 16 TO 44 PERCENT. REGARDLESS WHETHER THERE IS ANY
PRECIPITATION...THE CYCLONIC FLOW WILL KEEP CLOUDS ACROSS THE
REGION. THESE CLOUDS WILL TEMPER HIGH TEMPERATURES INTO THE LOWER
AND MID 50S AND KEEP LOW TEMPERATURES AROUND 40 DEGREES.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO SHOW THAT A LONG
WAVE TROUGH WILL DEVELOP ACROSS THE REGION. THIS TROUGH WILL KEEP
TEMPERATURES BELOW-NORMAL INTO NEXT WEEKEND. HIGH TEMPERATURES
WILL REMAIN IN THE LOWER AND MID 50S...AND LOW TEMPERATURES WILL
BE IN THE 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM CDT SAT OCT 12 2013
SURFACE LOW PRESSURE IS MOVING INTO WESTERN ONTARIO EARLY THIS
AFTERNOON. LARGE AREA OF WRAP AROUND CLOUDS FROM THE LOW IS
EXTENDING SOUTH ACROSS MUCH OF MINNESOTA. LATEST VISIBLE
SATELLITE IS SHOWING SOME DIURNAL CUMULUS FORMING ON THE SOUTHERN
EDGE OF THIS CLOUD SHIELD. THE 12.15Z RAP AND 12.12Z NAM BUFKIT
SOUNDINGS BOTH SHOW THE POTENTIAL FOR THESE DIURNAL CUMULUS TO
FORM A VFR CEILING AT BOTH AIRPORTS DURING THE AFTERNOON. THESE
CLOUDS SHOULD DISSIPATE LATE THIS AFTERNOON LEAVING BEHIND CLEAR
SKIES FOR THE REMAINDER OF THE PERIOD AS HIGH PRESSURE BUILDS IN
FROM THE WEST. THE CENTER OF THE HIGH WILL REMAIN SOUTH OF THE
REGION OVERNIGHT SO NOT EXPECTING THE WINDS TO COMPLETELY STILL
OFF...BUT KLSE BEING IN THE VALLEY COULD GO DOWN TO AN ALMOST CALM
WIND. HIGH WILL STILL BE OVER THE REGION FOR SUNDAY MORNING TO
CONTINUE THE CLEAR SKIES AND WEST TO NORTHWEST WINDS UNDER 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 239 PM CDT SAT OCT 12 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT
MOVING EAST OVER CENTRAL WISCONSIN AND ABOUT TO ENTER EASTERN
WISCONSIN. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CONTINUE
TO DEVELOP OVER EASTERN WISCONSIN AHEAD OF THE FRONT...THE HEAVIEST
WHICH IS MOVING ACROSS THE LAKE MICHIGAN SHORELINE. CANNOT RULE OUT
SHOWERS POPPING UP UNTIL THE FRONT EXITS...BUT LOOKS LIKE THE MOST
WIDESPREAD COVERAGE WILL HAVE PASSED TO THE EAST BY PRESS ISSUANCE.
BEHIND THE FRONT...A DRY SLOT IS PROVIDING A PERIOD OF CLEAR
CONDITIONS OVER PARTS OF WESTERN WISCONSIN. BUT OVER MINNESOTA AND
FAR WESTERN WISCONSIN...A LARGE AND SOLID STRATO-CU FIELD IS MOVING
EAST. SOME SHOWERS FALLING OUT OF THE CLOUD MASS UNDER THE COLDER
CLOUD TOPS. SMALL PRECIP CHANCES/CLOUDS/TEMPS ARE THE MAIN FORECAST
CONCERN IN THE SHORT-TERM.
TONIGHT...THE COLD FRONT WILL MOVE EAST OVER LOWER MICHIGAN WHILE
NORTHEAST WISCONSIN WILL SEE THE DRY SLOT MOVE OVERHEAD. SKIES WILL
BE CLEARING OVER NORTHEAST WISCONSIN AS A RESULT...WHICH WILL LEAD
TO A QUIET BUT BREEZY NIGHT. FARTHER WEST...SOLID MVFR STRATUS DECK
OVER MINNESOTA WILL MOVE NORTHEAST ACROSS WESTERN AND NORTHERN
SECTIONS OF THE FORECAST AREA TONIGHT. COLD ADVECTION/THERMAL
TROUGHING AND ENOUGH MOISTURE IN THE 850-700MB LAYER POINTS TOWARDS
THIS CLOUD MASS HOLDING TOGETHER AS IT MOVES ACROSS THE NORTHWEST
HALF OF THE FORECAST AREA. SOME SHOWERS NOTED IN THE OBS...BUT
ENHANCED CLOUD TOPS SUGGEST DEEPER MID-LEVEL MOISTURE IS PRESENT
OVER MN THAN WHAT WILL BE AROUND WHEN THE STRATUS DECK ARRIVES.
HAVE INCREASED CLOUD COVER AND MIN TEMPS TONIGHT...BUT STILL MAY NOT
BE HIGH ENOUGH. WILL PASS CONCERNS TO THE EVENING CREW. LOWS
MAINLY IN THE UPPER 30S TO LOW 40S.
SUNDAY...IF IT HAS NOT ALREADY DONE SO...THE LOW STRATUS DECK
WILL BE EXITING NORTHERN WISCONSIN EARLY SUNDAY MORNING. SOME
RESIDUAL MOISTURE MAY LEAD TO A SCT CU DECK FORMING BY LATE MORNING
OVER NORTH-CENTRAL WISCONSIN...BUT SHOULD SEE MOSTLY SUNNY
CONDITIONS ELSEWHERE. HIGHS IN THE UPPER 50S TO LOWER 60S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 239 PM CDT SAT OCT 12 2013
MODELS CONTINUE WITH SAME THOUGHTS THIS PERIOD AS AMPLIFIED YET
COLDER PATTERN EXPECTED OVER AREA AS RIDGE LIES OFF WEST COAST AND
DEEPENING TROF OVER THE EASTERN 2/3RDS OF CONUS. S/W ENERGY DROPPING SE
OUT OF PACIFIC NORTHWEST INTO SOUTHWEST STATES EXPECTED TO CLOSE
OFF OFF EARLY IN PERIOD IS FEATURE THAT BRINGS CONCERNS TO THIS
FORECAST PERIOD. STILL SOME ISSUES WITH TIMING BETWEEN MODELS AND
INDIVIDUAL RUNS OF MODELS. ECMWF SLOWEST WITH PCPN NOW HOLDING OUT
TIL LATER TUE. WITH SYSTEM CUTTING OFF IT WOULD SUGGEST A SLOWER
PROGRESSION. NEITHER GFS OR ECMWF IS REALLY FAVORED BY ENSEMBLE
MEANS SO WILL GO WITH A GENERAL BLEND FOR TUE AND WED. HAVE
TRENDED TOWARDS ECMWF FOR LATER PERIODS AS IT PULLS ENERGY/TROF
BACK OVER THE SOUTHWEST STATES PER ENSEMBLES. THIS WOULD LEAD TO
TEMPS A BIT WARMER THAN SEEN YESTERDAY OR CURRENT OPS GFS.
IN NEAR TERM...HIGH PRESSURE OVER REGION ON SUNDAY NIGHT. LIGHT
WINDS AND CLEAR SKIES TO LEAD TO COLD NIGHT. EXPECT TEMPS TO DROP
INTO THE 30S OVER THE REGION...DROPPING TO BELOW FREEZING IN
TYPICAL COLD SPOTS. PLEASANT FALL DAY EXPECTED MONDAY. EASTERLY
GRADIENT TO PICK UP AS LOW DEEPENS IN THE PLAINS. THIS WILL
MODERATE TEMPS SOME. MAY ALSO SEE SOME LAKE CLOUDS FROM TIME TO
TIME MONDAY GIVEN STILL RELATIVELY WARM WATERS. HAVE BACKED OFF A
BIT ON POPS MON NIGHT AS MODEL CROSS SECTIONS EVEN ON MORE
AGGRESSIVE GFS HOLDING ONTO DRY WEDGE BETWEEN 900 AND 700 MB INTO
TUE MORNING.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1218 PM CDT SAT OCT 12 2013
A COLD FRONT WILL PROGRESS ACROSS EASTERN WISCONSIN
EARLY THIS AFTERNOON WHICH WILL END THE SHOWER AND THUNDERSTORM
THREAT. A PERIOD OF CLEAR SKIES WILL THE FOLLOW IN THE WAKE OF THE
FRONT UNTIL A BKN/OVC AREA OF MVFR CIGS ROTATES NORTHEAST ACROSS
CENTRAL AND NORTH-CENTRAL WISCONSIN LATE THIS AFTERNOON THROUGH MUCH
OF TONIGHT. WINDS WILL ALSO TURN GUSTY OUT OF THE SOUTHWEST THIS
AFTERNOON AND THEN PARTIALLY DIMINISH EARLY THIS EVENING. THE
MVFR CLOUD DECK TO EXIT THE REGION LATE TONIGHT...WHICH WILL LEAVE
GOOD FLYING WEATHER FOR THE REST OF SUNDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CDT SAT OCT 12 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 250 AM CDT SAT OCT 12 2013
COLD FRONT TRUDGING ACROSS THE REGION EARLY THIS MORNING...MORE OR
LESS RESTING ALONG THE MISSISSIPPI RIVER AT 06Z. EARLY CONVECTION
AROUND THE FRONT HAS DIMINISHED WITH 88-D RADAR RETURNS DEPICTING
ONLY VERY SPOTTY SHOWERS. THE FRONT AND PCPN SHOULD BE NEARLY EAST
OF THE FORECAST AREA BY 12Z. MEANWHILE TO THE NORTH...AREAS OF
SHOWERS WILL TRACK EAST/NORTHEAST ACROSS NORTHERN MN...ASSOCIATED
WITH AN AREA OF LOW PRESSURE OVER CANADA. NONE OF THIS ACTIVITY IS
EXPECTED TO DIP FAR ENOUGH SOUTH TO IMPACT THE LOCAL AREA.
HIGH PRESSURE BUILDS IN TONIGHT...AND WILL HELP ROUND OUT THE
WEEKEND WITH SUNSHINE. THE CLEAR SKIES AND ANTICIPATED LIGHT WINDS
WILL HELP TEMPS TUMBLE THOUGH...WITH MID 30S EXPECTED ACROSS THE
COLD PRONE/DRAINAGE AREAS OF CENTRAL AND NORTH-CENTRAL WI. MOSTLY
ALONG AND NORTH/EAST OF THE I-94 CORRIDOR. IT WILL PROBABLY BE MORE
PATCHY IN NATURE...BUT IF TEMPS LOOK LIKE THEY COULD BE A COUPLE
DEGREES COLDER...A FROST ADVISORY WOULD BE NEEDED. MONDAY MORNING
PRESENTS A SIMILAR SCENARIO.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 250 AM CDT SAT OCT 12 2013
OVERALL...PRETTY GOOD AGREEMENT BETWEEN THE GFS/ECMWF/GEM/NAM WITH
BRINGING A RAINMAKER ACROSS THE REGION LATE MONDAY NIGHT...LIKELY
LINGERING THROUGH WED. THERE ARE DIFFERENCES IN TIMING...WITH THE
NAM A BIT FASTER THAN THE REST...A TAD MORE NORTH. ON THE
WHOLE...ALL PROMISE A PERIOD OF WETTING...WITH 1/2 TO 1 INCH OF RAIN
POSSIBLE.
AN UPPER LEVEL SHORTWAVE WILL EJECT OUT OF THE WEST COAST
TROUGH...SPINNING ACROSS THE DAKOTAS MONDAY...AND GRADUALLY SLIPPING
WEST TO EAST ACROSS THE UPPER MISSISSIPPI TUE-WED. THE SYSTEM/S SFC
LOW WILL TRACK INTO SOUTHERN MN ON TUE...GRADUALLY EXIT EAST WITH
THE UPPER LEVEL TROUGH ON WED. FAIRLY STRONG QG CONVERGENCE THROUGH
THE 850-300 MB LAYER WITH THE STORM SYSTEM...DEEPEST/STRONGEST
ACROSS MN/NORTHERN WI...GENERALLY NORTH OF THE SFC LOW. GOOD SHOT OF
LOW LEVEL WARM AIR ADVECTION ALSO ACCOMPANIES THE LOW...WITH A 50 KT
850 MB JET NOSING MOISTURE AHEAD OF THE SYSTEM. A LOT OF UPPER
AIR/THERMODYNAMIC FORCING WITH THE STORM...AND AMPLE MOISTURE TO
FUEL IT. RAIN REMAINS LIKELY AS A RESULT...WITH SOME AFOREMENTIONED
TIMING/PLACEMENT CONCERNS FOR THE HIGHER CHANCES. UNSURE ON IF THERE
WILL BE ANY ISOLATED/SCATTERED STORMS TO CONTEND WITH. NO
INSTABILITY INDICATED VIA THE GFS...BUT THE DYNAMICS ARE PRETTY
STRONG...AND THAT ALONE COULD BE STRONG ENOUGH TO SPARK A
THUNDERSTORM OR TWO. FOR NOW...WILL KEEP STORMS OUT OF THE FORECAST.
A TROUGH WILL HANG WEST OF THE EXITING SFC LOW FOR TUE
NIGHT/WED...INTERACTING THE UPPER LEVEL ENERGY IN THE 500 MB
SHORTWAVE. SHOWERS SHOULD CONTINUE AS RESULT...LIKELY FOCUSED AROUND
THE SFC BOUNDARY.
COLDER AIR FLOWS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FOR
THU/FRI. COUPLE THIS WITH FAVORABLE LOW LEVEL LAPSE RATES AND
LINGERING MOISTURE AND ISOLD/SCT SHOWERS ARE LIKELY. CURRENT
PLACEMENT OF THE COLDER AIR/MOISTURE WOULD KEEP MOST OF THE SHOWERS
ACROSS NORTHERN PARTS OF MN/WI...WITH SOME DIURNAL ELEMENTS TO THE
SHOWERS ALSO PROBABLE.
TEMPERATURES WILL CONTINUE TO TUMBLE. HIGHS BY THE END OF THE WORK
WEEK WILL STRUGGLE TO REACH 50 IN AREAS TO THE NORTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM CDT SAT OCT 12 2013
SURFACE LOW PRESSURE IS MOVING INTO WESTERN ONTARIO EARLY THIS
AFTERNOON. LARGE AREA OF WRAP AROUND CLOUDS FROM THE LOW IS
EXTENDING SOUTH ACROSS MUCH OF MINNESOTA. LATEST VISIBLE
SATELLITE IS SHOWING SOME DIURNAL CUMULUS FORMING ON THE SOUTHERN
EDGE OF THIS CLOUD SHIELD. THE 12.15Z RAP AND 12.12Z NAM BUFKIT
SOUNDINGS BOTH SHOW THE POTENTIAL FOR THESE DIURNAL CUMULUS TO
FORM A VFR CEILING AT BOTH AIRPORTS DURING THE AFTERNOON. THESE
CLOUDS SHOULD DISSIPATE LATE THIS AFTERNOON LEAVING BEHIND CLEAR
SKIES FOR THE REMAINDER OF THE PERIOD AS HIGH PRESSURE BUILDS IN
FROM THE WEST. THE CENTER OF THE HIGH WILL REMAIN SOUTH OF THE
REGION OVERNIGHT SO NOT EXPECTING THE WINDS TO COMPLETELY STILL
OFF...BUT KLSE BEING IN THE VALLEY COULD GO DOWN TO AN ALMOST CALM
WIND. HIGH WILL STILL BE OVER THE REGION FOR SUNDAY MORNING TO
CONTINUE THE CLEAR SKIES AND WEST TO NORTHWEST WINDS UNDER 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1131 AM CDT SAT OCT 12 2013
.UPDATE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE
SHIFTING NORTH NORTHEAST THROUGH MAINLY SOUTHEAST WISCONSIN AT
THIS TIME. THESE WERE BEING DRIVEN BY COLD FRONT MOVING EAST
THROUGH THE AREA...ALONG WITH PASSING 500MB VORTICITY
MAXIMUM...AND WEAK TO MODEST LOW LEVEL FRONTOGENESIS RESPONSE.
AREA FORECAST SOUNDINGS SUPPORT CONTINUATION OF SHOWERS AND
ISOLATED STORMS THROUGH MID AFTERNOON...UNTIL COLD FRONT/LOW LEVEL
FRONTOGENESIS RESPONSE MOVES EAST OF THE AREA. HRRR AND OTHER
HIGH RESOLUTION MODELS SHOW AN AREA OF SHOWERS BECOMING BETTER
ORGANIZED OVER THE FAR EASTERN COUNTIES AND OVER LAKE MICHIGAN
BETWEEN 20Z AND 22Z...SO CONTINUED TO HAVE THE HIGHEST POPS IN
THAT AREA.
CLOUDS WILL CLEAR AREA FROM WEST TO EAST BEHIND COLD FRONT BY
SUNSET...WITH DOWNWARD MOTION FROM COLD AIR ADVECTION. SHOULD SEE
HIGHS REMAIN IN THE MID TO UPPER 60S AHEAD OF THE FRONT...WITH
VALUES SLOWLY FALLING BEHIND IT WITHIN THE COLD AIR ADVECTION.
&&
.AVIATION/18Z TAFS/...SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS ARE EXPECTED AT EASTERN TAF SITES UNTIL AROUND 23Z.
COLD FRONT WILL MOVE EAST THROUGH THE AREA THIS
AFTERNOON...HELPING GENERATE THE PRECIPITATION. SOUTH WINDS AHEAD
OF THE FRONT WILL SHIFT WEST BEHIND IT DURING THE AFTERNOON...WITH
MVFR/VFR CLOUD DECK SCATTERING OUT FROM WEST TO EAST SOON AFTER.
HIGH PRESSURE MOVING EAST INTO THE REGION TONIGHT AND SUNDAY WILL
BRING VFR CONDITIONS...WITH WEAKENING WEST WINDS AND CLEAR SKIES.
LIGHT NORTHWEST WINDS ARE EXPECTED ON SUNDAY...WITH SUNNY SKIES.
&&
.MARINE...SMALL CRAFT ADVISORY CONTINUES FOR ALL OF THE NEARSHORE
WATERS UNTIL 23Z. REPORT FROM LARGE BARGE CAPTAIN 2 MILES EAST OF
RACINE INDICATED HIGH WAVES WERE OCCURRING...SO EXPANDED THE SMALL
CRAFT ADVISORY FOR THE ENTIRE NEARSHORE WATERS UNTIL 23Z.
BREEZY SOUTH SOUTHEAST WINDS WERE HELPING GENERATE 3 TO 6 FOOT
WAVES IN THE NEARSHORE WATERS. WINDS WILL VEER SOUTHWEST TO WEST
LATE THIS AFTERNOON AND EARLY EVENING...AS THE COLD FRONT MOVES
EAST THROUGH THE AREA. WINDS WILL ALSO DIMINISH DURING THIS
TIME...ALLOWING WAVES TO SUBSIDE BELOW 4 FEET BY EVENING.
&&
.PREV DISCUSSION... /ISSUED 343 AM CDT SAT OCT 12 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH
DECENT SHORTWAVE AND COLD FRONT WILL BRING A ROUND OF SHOWERS TO
SOUTHERN WISCONSIN TODAY. HAVE ALREADY SEEN A SHOWER OR TWO IN THE
WEST AND EXPECTING COVERAGE WILL PICK UP INTO THE MORNING. BEST
CHANCE SEEMS TO BE IN THE EASTERN TWO-THIRDS OF THE FORECAST AREA
MID MORNING INTO EARLY AFTERNOON AS BETTER LOW LEVEL FRONTOGENESIS
AND UPPER DIVERGENCE FROM REAR JET ENTRANCE REGION MOVE THROUGH.
GIVEN SOME LIGHTNING UPSTREAM AND ELEVATED CAPE IN SOUNDINGS...LEFT
ISOLATED THUNDER IN THE FORECAST.
THERE WILL BE A PRETTY GOOD PUNCH OF DRY AIR BEHIND THE FRONT THIS
AFTERNOON...SO SHOULD SEE SKIES CLEAR PRETTY QUICKLY...WITH MOSTLY
SUNNY SKIES EARLY AFTERNOON WEST AND LATE AFTERNOON EAST. ALREADY
UPPER 50S AND LOW 60S MOST PLACES...EVEN MID TO UPPER 60S WEST...SO
HIGHS IN THE UPPER 60S TO AROUND 70 STILL SEEM REASONABLE.
WILL SEE MOSTLY CLEAR SKIES AND NEAR NORMAL TEMPS TONIGHT AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE WEST.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE HIGH.
UPPER LEVEL RIDGE AND SURFACE HIGH WILL DRIFT ACROSS THE GREAT LAKES
REGION SUNDAY AND MONDAY. SUNNY SKIES...DRY AIR AND 925MB TEMPS
AROUND 8C-9C WILL LEAD TO HIGHS IN THE LOWER 60S. WITH LIGHT
WINDS...SUNDAY NIGHT LOWS WILL DIP INTO THE MID 30S INLAND FROM THE
LAKE. KEPT THEN MENTION OF PATCHY FROST FOR MUCH OF THE AREA.
LONG TERM...
MONDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
A HIGH-AMPLITUDE UPPER LOW OVER THE WESTERN U.S. WILL BRING ANOTHER
DEEP SURFACE LOW ACROSS THE PLAINS AND INTO THE GREAT LAKES REGION
AS IT OCCLUDES AND WEAKENS. MODELS ARE TRENDING SLOWER WITH THE
PRECIP ARRIVAL IN SOUTH CENTRAL WI UNTIL EARLY TUESDAY MORNING
NOW...WHICH MAKES SENSE GIVEN THE DRY AIR IN PLACE OVER THE GREAT
LAKES.
PRECIP CHANCES WILL CONTINUE TO BE HIGHER TOWARD CENTRAL WI RATHER
THAN SOUTHERN WI AS A SECONDARY SURFACE LOW IS FORECAST TO TRACK
RIGHT ACROSS THE MKX FORECAST AREA. THE DRY AIR WILL WRAP INTO
SOUTHERN WI TUE NIGHT AS THE SYSTEM TRACKS EASTWARD.
LIGHT SHOWERS AND CLOUDS WILL LINGER OVER CENTRAL AND SOUTHERN WI
THROUGH AT LEAST WEDNESDAY MORNING...BUT POTENTIALLY THROUGH
THURSDAY MORNING IF THE SLOWER 00Z ECMWF SOLUTION PANS OUT.
FRIDAY AND BEYOND...FORECAST CONFIDENCE MEDIUM.
ANOTHER UPPER TROUGH WILL DROP DOWN OUT OF WESTERN CANADA AND SETTLE
OVER THE UPPER MIDWEST THURSDAY NIGHT THROUGH THE WEEKEND. 850MB
TEMPS ARE EXPECTED TO DROP TO AROUND -2C. THIS MEANS HIGHS IN THE
50S FOR FRIDAY AND SATURDAY...AND A POTENTIAL WIDESPREAD FREEZE
SATURDAY NIGHT. OF COURSE...THERE ARE MODEL DIFFERENCES AND
RUN-TO-RUN INCONSISTENCIES THAT FAR OUT AND CLOUDS AND PRECIP COULD
INHIBIT THE FREEZE. STAY TUNED.
AVIATION/12Z TAFS/...
WILL SEE SHOWERS AND A FEW RUMBLES OF THUNDER THIS
MORNING...AFFECTING AREAS WEST FIRST AND THEN WINDING DOWN IN THE
EAST BY EARLY OR MID AFTERNOON. COULD SEE SOME BRIEF MVFR CIGS AS
THE COLD FRONT AND SHOWERS MOVE THROUGH...BUT OTHERWISE VFR
CONDITIONS WILL CONTINUE THROUGH THE DAYTIME AND OVERNIGHT HOURS.
MARINE...
THE CURRENT SMALL CRAFT ADVISORY NORTH OF PORT WASHINGTON STILL
SEEMS REASONABLE. WILL SEE BREEZY SOUTHERLY WINDS TODAY WITH GUSTS
TO AROUND 20 KNOTS. THESE PERSISTENT WINDS WILL KEEP WAVES OF 3 TO 5
FEET ACROSS THIS AREA INTO THE AFTERNOON. WINDS WILL EVENTUALLY VEER
TO THE SOUTHWEST THIS AFTERNOON AND EASE A BIT...ALLOWING THE WAVES
TO SUBSIDE SOME BY EVENING. COULD SEE SOME HIGHER WAVES LINGER A BIT
LONGER THAN PREVIOUSLY EXPECTED...SO WILL EXTEND THE ADVISORY
EXPIRATION TIME FROM 20Z TO 23Z.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DDV
SUNDAY THROUGH FRIDAY...MRC