Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/28/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
830 PM MDT FRI SEP 27 2013
.UPDATE...UPPER LEVEL TROUGH WILL MOVE ACROSS COLORADO TONIGHT.
DRIER AIR IS MOVING EAST ACROSS THE STATE. ALREADY SEEING BREAKS
IN THE CLOUDS OVER THE HIGH COUNTRY AND OVER THE FOOTHILLS. THIS
DRIER AIR WILL SPREAD EAST ACROSS EASTERN COLORADO AND BRING THE
SHOWERS AN END THIS EVENING. ADJUSTED POPS TO MATCH UP WITH
CURRENT TRENDS AND STILL APPEARS MOST OF THE PRECIPITATION WILL
END BY MIDNIGHT. MY SEE A FEW LINGERING SNOW SHOWERS OVER THE
MOUNTAINS AND RAIN SHOWERS OVER EASTERN COLORADO AFTER MIDNIGHT.
SKIES ARE EXPECTED TO CLEAR LATER TONIGHT. AIRMASS IS QUITE COOL
WITH EVEN THE MOUNTAIN VALLEYS NEAR OR BELOW FREEZING ALREADY.
THE LATEST HRRR AND RUC SHOW LOWS IN THE MID 30S ALONG THE FRONT
RANGE AND OVER THE EASTERN PLAINS. LINGERING CLOUDS MAY KEEP THE
FAR EASTERN PLAINS SLIGHTLY WARMER. EXPECT SOME FROST AROUND
SUNRISE IN THE LOW LYING AREAS WHERE THE COLD AIR SETTLES...THUS
EXPANDED THE FROST ADVISORY. MAY ALSO SEE SOME FOG IN THE LOW
LYING AREAS TOO.
&&
.AVIATION...THE RAIN SHOWERS AND LOW CLOUDS WILL DECREASE RAPIDLY
THROUGH THE EVENING HOURS. BY 06Z SCATTERED TO BROKEN MID CLOUDS
ARE EXPECTED AND BY 12Z MOSTLY CLEAR SKIES SHOULD PREVAIL. WILL BE
SCATTERED FOG AROUND 12Z IN LOW LYING AREAS...BUT EXPECT THE
DENVER AIRPORTS TO REMAIN FOG FREE...THOUGH THERE IS A SLIGHT
CHANCE FOR SEEING FOG FOR A SHORT TIME.
&&
.PREV DISCUSSION... /ISSUED 249 PM MDT FRI SEP 27 2013/
SHORT TERM...THE WATER VAPOR PICTURES ARE SHOWING THE UPPER
RIDGE AXIS JUST EAST OF THE WESTERN COLORADO BORDER. THERE ARE
TWO BATCHES OF SHOWERS MOVING ACROSS THE STATE RIGHT NOW...ONE
OVER THE EASTERN FOOTHILLS/URBAN CORRIDOR AND THE OTHER OVER THE
WESTERN HALF OF COLORADO. THE VISIBLE PICTURES SHOW NEARLY ALL THE
PLAINS ARE COMPLETELY COVERED BY CLOUDS. THAT SOUTHERN HALF OF
LINCOLN COUNTY WAS THE HOLD OUT...BUT CONVECTIVE CLOUDINESS IS
INCREASING THERE NOW. NORTH-NORTHEAST UPSLOPE WINDS ARE COVERING
ALL THE PLAINS UP INTO THE LOWER FOOTHILLS...MAYBE UP TO 7500 FEET
MSL. THE CURRENT SNOW LEVEL IS AROUND 8500 FEET MSL. THE SYNOPTIC
SCALE ENERGY ON THE QG VERTICAL VELOCITY FIELDS IS STILL PRETTY
SIGNIFICANT THIS EVENING OVER THE PLAINS. BY 12Z...THE UPPER
TROUGH AXIS IS PROGGED TO BE JUST EAST OF THE CWA. THE BOUNDARY
LAYER FLOW IS PROGGED TO BE NORTHWESTERLY THIS EVENING...THEN IT
GOES BACK TO NORMAL DIURNAL PATTERNS THROUGH SATURDAY. MODELS KEEP
THE MOISTURE AROUND UNTIL LATE EVENING...THEN IT DECREASES RAPIDLY
AND SIGNIFICANTLY. THERE IS SOME MEASURABLE PRECIPITATION THIS
EVENING...BUT ITS GONE BY 06Z TONIGHT. NOTHING ON SATURDAY. WILL
DROP THE SNOW LEVEL TO 7500 FEET MSL. WITH GO WITH A "CHANCE"S
OVER THE WESTERN THREE-QUARTER OF THE CWA THIS EVENING. THE
EASTERN QUARTER WILL HAVE "LIKELY"S. IT`S MAINLY A FUNCTION OF
TIMING THE UPPER TROUGH FROM THE REAL DATA. SATURDAY IS DRY. FOR
TEMPERATURES...DEPENDING ON HOW FAST IT CLEARS OUT...SOME OF THE
PLAINS COULD SEE FREEZING READINGS. WILL LEAVE THE FROST HIGHLIGHT
AS IS. SATUDAY`S HIGHS ARE 4-8 C WARMER THAN TODAY`S.
LONG TERM...FINALLY SOME SEPTEMBER WEATHER COMING JUST IN TIME
FOR OCTOBER. BROAD UPPER RIDGE WILL DOMINATE THE WEATHER THIS
WEEK WITH A COUPLE WEAK SHORTWAVES. ONE PASSES NORTH OF US ABOUT
MONDAY NIGHT...WITH HINTS OF A WEAKER WAVE OVER OR SOUTH OF US
ABOUT WEDNESDAY. NEITHER OF THESE LOOKS LIKE IT WILL HAVE MUCH
DYNAMICS OR MOISTURE TO WORK ON...BUT THEY MAY BRING LITTLE PUFFS
OF NORTH WIND TO LIMIT THE WARMTH...AND ALSO SOME HIGH CLOUDINESS
AT TIMES. IN GENERAL THOUGH...IT WILL BE A DRY WITH TEMPERATURES
NEAR OR ABOVE NORMAL...MAINLY 70S AND PERHAPS A FEW 80S EARLY IN
THE WEEK. WITH LONGER NIGHTS AND DRY AIR...MORNINGS WILL START
COOL WHICH WILL ALSO KEEP TEMPERATURES FROM RISING TOO MUCH PAST
80.
PRETTY GOOD AGREEMENT ON THE NEXT TROUGH FOR THAT FAR OUT...BUT
TIMING REMAINS PROBLEMATIC WITH MODELS GOING BACK AND FORTH
BETWEEN THURSDAY AND FRIDAY. AT THIS POINT THE SYSTEM LOOKS
PROGRESSIVE...BUT THIS COULD CHANGE. SOME COOLER AIR AND A CHANCE
OF PRECIPITATION AT LEAST...WE COULD GET SNOW DOWN INTO THE
FOOTHILLS BUT IT LOOKS TOO WARM FOR THE PLAINS. GENERALLY WENT
WITH THE MODEL CONSENSUS WHICH SMEARS OUT THE TIMING DETAILS
THURSDAY/FRIDAY...DID NUDGE THE POPS UP IN THE MOUNTAINS WHERE THE
CONSENSUS HAS A LOW BIAS.
AVIATION...CEILING ARE EXPECTED TO STAY BELOW 1000 AGL AT DIA
THROUGH ABOUT 02Z...THEN THEY INCREASE. BY 06Z...CEILINGS SHOULD
BE GONE ALTOGETHER. VISIBILITIES AT DIA SHOULD RANGE FROM 3-6SM
THROUGH 02Z...THEN THEY GET ABOVE 6SM BY 03Z. WINDS WILL STAY
NORTH-NORTHEASTERLY THROUGH ABOUT 02Z...THEN GO NORTHWESTERLY.
THEY WILL DECREASE IN SPEED BY MID TO LATE EVENING. NORMAL
DRAINAGE PATTERN WINDS ARE LIKELY AFTER 09Z OVERNIGHT.
HYDROLOGY...PRECIPITATION AMOUNTS FROM THIS CURRENT STORM COULD
PRODUCE WILL RANGE FORM 0.10 TO 0.30 INCH BY MIDNIGHT TONIGHT.
THAT IS FOR ALL OF THE FORECAST AREA. THERE WILL BE NO
PRECIPITATION AFTER MIDNIGHT TONIGHT THROUGH SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM TO 8 AM MDT SATURDAY FOR COZ038>046.
&&
$$
SHORT TERM...RPK
LONG TERM....GIMMESTAD
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1153 AM MDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1002 AM MDT THU SEP 26 2013
THE 12Z NAM12 CONTINUES TO SHOW SIGNIFICANT SNOWFALL OVER THE
HIGHER TERRAIN OF THE EASTERN UINTA MOUNTAINS IN NORTHEAST UT.
CURRENT FORECAST OF 4-8 INCHES ABOVE 9000 FT REMAINS REASONABLE WITH
SOME LOCALLY HIGHER AMTS POSSIBLE. SINCE THIS LOOKS LIKE THE FIRST
GOOD EARLY-SEASON SNOW EVENT FOR THIS AREA...DECIDED TO HEIGHTEN
AWARENESS EVEN MORE BY UPGRADING THE CURRENT WINTER WEATHER
ADVISORY FOR THE EASTERN UINTA MTNS (UT ZONE 23) TO A WINTER STORM
WARNING. ANTICIPATE THE BEST SNOW ACCUMULATIONS TO OCCUR BETWEEN
MIDNIGHT AND NOON FRI.
FOR WESTERN COLORADO...EARLY LOOK AT THE MODELS INDICATE THAT SNOW
LEVELS REMAIN HIGH UNTIL LATE TONIGHT AND FRIDAY MORNING. USING
WET-BULB ZERO AS AN INDICATOR...SNOW LEVELS STAY ABOVE 10K ALONG
THE DIVIDE DOWN ACROSS THE SAN JUANS UNTIL AFTER 12Z FRI...WHILE
DROPPING TO AROUND 9K OVER GRAND MESA BY 12Z FRI. ONCE THE FRONT
PASSES...SNOW LEVELS SHOULD DROP QUICKLY.
IN OTHER NEWS...WILL CONTINUE WITH THE CURRENT WIND ADVISORY FOR
THE VALLEYS OF SE UT AND PORTIONS OF SW CO TODAY. LATEST HIGH-
RESOLUTION HRRR MODEL INDICATES STRONG WIND GUSTS EXPANDING INTO
NW CO (CO ZONES 1 AND 2) THIS AFTERNOON AS THE COLD FRONT
TEMPORARILY RETREATS. WILL CONTINUE TO EVALUATE AND WATCH IN CASE
THE WIND ADVISORY NEEDS EXPANSION INTO THIS AREA.
UPDATE ISSUED AT 813 AM MDT THU SEP 26 2013
UDOT WEBCAMS REVEALED SOME LIGHT SNOW AT 8000 FT HAD OCCURRED ACROSS
THE ERN UINTA MTNS LAST NIGHT AND THIS MORNING BEHIND THE COLD
FRONT. DID A QUICK UPDATE TO THE GRIDDED AND WORDED FORECASTS FOR
UT ZONE 23 TO TAKE THIS INTO ACCOUNT. EXPECT MUCH OF THIS SNOW
WILL MELT TODAY AS THE FRONT WAVERS BACK NORTHWEST AND TEMPS RISE
INTO THE 40S.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 338 AM MDT THU SEP 26 2013
THE COLD FRONT ASSOCIATED WITH THE BROAD UPPER-LEVEL TROUGH
ENCOMPASSING MUCH OF THE NORTHERN INTERMOUNTAIN WEST LAY ALONG A
KBCE-35N KGJT-KEEO-K3MW LINE EARLY THIS MORNING. SOME VIRGA WAS
EVIDENT IN KGJX RADAR IMAGERY RESULTING FROM OVERRUNNING OF THE
FRONT. LITTLE MOISTURE ENTRAINED IN THE SOUTHWEST FLOW WHICH
EXPLAINS WHY MOISTURE WASN/T REACHING THE GROUND.
THE TROUGH IS EXPECTED TO DIG SOUTHWARD IN RESPONSE TO A 125KT JET
PLUNGING SOUTHWARD ON ITS BACK SIDE. THIS WILL CAUSE THE AXIS OF
THE TROUGH TO LOSE SOME OF ITS POSITIVE TILT WHICH...IN TURN...WILL
RESULT IN THE FRONT LIFTING BACK TO THE NORTHWEST AS A WARM FRONT.
BECAUSE SYSTEM DRAWING FROM DRYER AIRMASS TO THE SOUTH CUT POPS
ACROSS ALL BUT THE EASTERN UINTA MOUNTAINS TODAY. IN THIS REGION
INSTABILITY SUPPORTS THE FORMATION OF A FEW EMBEDDED
THUNDERSTORMS.
PRE-FRONTAL SOUTHWEST WINDS WILL CONTINUE TO BE RATHER STRONG ACROSS
THE AREA AGAIN THIS AFTERNOON. A CORE OF 45 KNOT WINDS AT THE 7H
LEVEL OVER SOUTHEAST UTAH AND SOUTHWEST COLORADO APPEARS DURING
THE AFTERNOON AS THE MID-LEVEL AND SURFACE GRADIENTS TIGHTEN WITH
THE APPROACH OF THE TROUGH. GIVEN YESTERDAY/S WINDS...NO REASON
TO BELIEVE WIND ADVISORY FOR LOWER ELEVATIONS OF SOUTHEAST UTAH AND
SOUTHWEST COLORADO WON/T VERIFY. THEREFORE...WILL CONTINUE THE WIND
ADVISORY FROM NOON TO 7 PM. SINCE MODELS WERE IN GOOD AGREEMENT
WITH PLACEMENT OF THE 7H WIND MAX OVER THE ADVISED AREA AND WERE
CONSISTENT WITH PREVIOUS RUNS HAVE NO PLANS TO EXPAND WIND HILITES.
THOUGH MUCH OF THE FORECAST AREA WILL BE IN THE WARM SECTOR AGAIN
TODAY...COOLING AT 7H LEVELS WILL RESULT IN A FEW DEGREES OF
COOLING THIS AFTERNOON. MET GUIDANCE SEEMED TO BE PICKING UP ON
THIS TREND BETTER THAN THE MAV GUIDANCE DESPITE THE FACT THAT THE
GFS SHOWED SIMILAR 7H COOLING.
TONIGHT AND FRIDAY...120+KT JET IS DROPPING DOWN THE CALIFORNIA
COAST THIS MORNING AND WILL HELP CARVE OUT THE WESTERN TROF
TODAY AS IT REFORMS ON THE DOWNSTREAM SIDE OVER THE ROCKIES THIS
EVENING. THIS WILL BEGIN TO PUSH THE TROF EASTWARD SUPPLYING A
STRONG AREA OF ASCENT AND INSTABILITY TO NORTHERN UTAH...WITH THE
TROP FOLD LOWERING TO NEAR 450MB. MODELS STILL WANT TO PUSH
MOISTURE UP THE 315K SURFACE THROUGH TODAY...BRINGING PWATS UP TO
NEAR NORMAL FOR LATE SEPTEMBER. THIS IS LESS THAN WHAT HAS BEEN IN
PLACE LATELY BUT THE DYNAMICS WITH THIS STORM LOOK SUFFICIENT TO
BRING A PERIOD OF MODERATE SNOWFALL TO THE NORTHWEST CWA
OVERNIGHT. A COLD FRONT MOVING THROUGH NORTHEAST UTAH THIS EVENING
APPEARED TO LINK UP WITH THE UPPER ASCENT BY MID LEVEL
FRONTOGENESIS...WITH THE NAM EVEN HINTING AT A COUPLED JET OVER
THIS REGION. MODELS ALSO HINT AT THE DRY CONVEYOR BELT LIFTING
ACROSS THIS REGION WITH PV LOBE PROVIDING INSTABILITY AND HAVE PUT
ISOLATED THUNDERSTORMS IN THE FORECAST. THE INSTABILITY...MOISTURE
AND LIFT ALL POINT TO A FEW HOURS OF MODERATE TO HEAVY SNOWFALL.
IT SHOULD BE NOTED THAT SNOW WAS SEEN TODAY AT 8000 FEET IN THE
EASTERN UINTAS THOUGH DYNAMICS WHERE WEAKER. GIVEN THE ABOVE...FELT
ADVZY LEVEL SNOWS MOST LIKELY TO IMPACT TRAVEL ROUTES WITH HIGHER
AMOUNTS OVER 10000 FEET. MODELS KEEP THE DENDRITIC LAYER SATURATED
UP NORTH SO POPS REMAIN THE HIGHEST HERE. A MOIST SOUTHWEST FLOW
AND INSTABILITY WILL BRING SOME CHANCE OF SNOWFALL TO THE HIGHER
MOUNTAINS IN THE CENTRAL AND SOUTH OVERNIGHT. THERMO PROFILES AND
DRIER ICE LAYER INDICATES HOWEVER THIS WILL BE FAIRLY LIGHT AND
MAINLY ABOVE THE 10000 FT LEVEL. THE FRONT WILL CONTINUE TO
PROGRESS ACROSS THE CWA ON FRIDAY...DRIVEN BY THE PROGRESSIVE TROF
ALOFT. MOISTURE LOOKS TO BE ON THE WAY OUT BUT INSTABILITY RE-
ENFORCED BY COLD AIR ALOFT. THE NORTHERLY FLOW WILL CONTINUE TO
FAVOR THE EASTERN UINTAS THROUGH THE DAY AS COLD AIR FILTERS IN.
SCATTERED SHOWERS ALSO CONTINUE ALONG THE FRONT AND THE HIGHER
TERRAIN OF WESTERN COLORADO. PROFILES OVER MANY VALLEY AREAS WERE
QUITE DRY IN THE LOWER LEVELS SO BACKED OFF ON POPS IN SEVERAL
PLACES. FRIDAY HIGHS WILL FALL BY SOME 10 TO 15 DEGREES BEHIND
THE FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 AM MDT THU SEP 26 2013
FRIDAY NIGHT INTO SATURDAY...CLEARING SKIES IN THE DRIER AIRMASS
WILL SPELL A COLD NIGHT ACROSS MUCH OF THE REGION AND FREEZING
TEMPERATURES WILL BE MORE COMMON ACROSS SOME OF THE LOWER
ELEVATIONS. LOOKS LIKE SOUTHERN FOOTHILLS OF THE SAN JUANS...
NORTHERN PLATEAUS...UINTA BASIN AND UPPER COLORADO MAY ALL BE IN
THREAT OF A SEASON ENDING FREEZE. RIDGING BUILDS IN FOR SATURDAY
AND TEMPERATURES WILL BEGIN A TREND BACK UPWARDS. THE COLD START
AND STRONGER INVERSION WILL KEEP TEMPERATURES ON THE COOL SIDE OF
NORMAL...BUT A DECENT START TO THE WEEKEND SHOULD COMMENCE.
SATURDAY NIGHT TO WEDNESDAY...FLAT ZONAL FLOW PREDOMINATES THROUGH
THE REMAINDER OF THE WEEK AND INTO THE MIDDLE OF THE COMING
WEEK. AS A RESULT...EXPECT DRY AND MILD CONDITIONS THROUGH
WEDNESDAY. TEMPERATURES WILL WARM A BIT RISING TO NEAR NORMAL BY
MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1152 AM MDT THU SEP 26 2013
A COLD FRONT FROM THE UTAH BOOK CLIFFS TO THE FLATTOPS WILL PUSH TO
THE NORTHWEST THIS AFTERNOON. THE FRONT WILL EXTEND FROM NEAR KBCE
TO KRWL LINE THIS AFTERNOON WHEN WINDS REACH THEIR PEAK. THE
STRONGEST WINDS ARE EXPECTED OVER SOUTHEAST UTAH AND PORTIONS OF
SOUTHWEST COLORADO WHERE SUSTAINED WINDS FROM 20 TO 30 MPH WITH
GUSTS TO NEAR 50 MPH ARE ANTICIPATED. EXPECT ANOTHER DAY OF
INCREASED MECHANICAL TURBULENCE OVER RIDGETOPS. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER NORTHEAST UT
AND EXTREME NORTHWEST CO THIS AFTERNOON INTO EARLY EVENING.
CIGS LOWER TO MOUNTAIN TOP LEVEL TONIGHT WITH THE COLD FRONT
RETURNING THROUGH NORTHEAST UT BY 06Z...AND ACROSS WESTERN COLORADO
BY 18Z FRI. VALLEY RAIN AND MOUNTAIN RAIN/SNOW WILL INCREASE IN
COVERAGE AFTER 06Z MAINLY NORTH OF INTERSTATE 70.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR COZ020-021.
FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR
COZ002-008-021>023.
UT...WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR UTZ022-027-029.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY
FOR UTZ023.
&&
$$
UPDATE...JAD
SHORT TERM...NL/15
LONG TERM...15/NL
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1002 AM MDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1002 AM MDT THU SEP 26 2013
THE 12Z NAM12 CONTINUES TO SHOW SIGNIFICANT SNOWFALL OVER THE
HIGHER TERRAIN OF THE EASTERN UINTA MOUNTAINS IN NORTHEAST UT.
CURRENT FORECAST OF 4-8 INCHES ABOVE 9000 FT REMAINS REASONABLE WITH
SOME LOCALLY HIGHER AMTS POSSIBLE. SINCE THIS LOOKS LIKE THE FIRST
GOOD EARLY-SEASON SNOW EVENT FOR THIS AREA...DECIDED TO HEIGHTEN
AWARENESS EVEN MORE BY UPGRADING THE CURRENT WINTER WEATHER
ADVISORY FOR THE EASTERN UINTA MTNS (UT ZONE 23) TO A WINTER STORM
WARNING. ANTICIPATE THE BEST SNOW ACCUMULATIONS TO OCCUR BETWEEN
MIDNIGHT AND NOON FRI.
FOR WESTERN COLORADO...EARLY LOOK AT THE MODELS INDICATE THAT SNOW
LEVELS REMAIN HIGH UNTIL LATE TONIGHT AND FRIDAY MORNING. USING
WET-BULB ZERO AS AN INDICATOR...SNOW LEVELS STAY ABOVE 10K ALONG
THE DIVIDE DOWN ACROSS THE SAN JUANS UNTIL AFTER 12Z FRI...WHILE
DROPPING TO AROUND 9K OVER GRAND MESA BY 12Z FRI. ONCE THE FRONT
PASSES...SNOW LEVELS SHOULD DROP QUICKLY.
IN OTHER NEWS...WILL CONTINUE WITH THE CURRENT WIND ADVISORY FOR
THE VALLEYS OF SE UT AND PORTIONS OF SW CO TODAY. LATEST HIGH-
RESOLUTION HRRR MODEL INDICATES STRONG WIND GUSTS EXPANDING INTO
NW CO (CO ZONES 1 AND 2) THIS AFTERNOON AS THE COLD FRONT
TEMPORARILY RETREATS. WILL CONTINUE TO EVALUATE AND WATCH IN CASE
THE WIND ADVISORY NEEDS EXPANSION INTO THIS AREA.
UPDATE ISSUED AT 813 AM MDT THU SEP 26 2013
UDOT WEBCAMS REVEALED SOME LIGHT SNOW AT 8000 FT HAD OCCURRED ACROSS
THE ERN UINTA MTNS LAST NIGHT AND THIS MORNING BEHIND THE COLD
FRONT. DID A QUICK UPDATE TO THE GRIDDED AND WORDED FORECASTS FOR
UT ZONE 23 TO TAKE THIS INTO ACCOUNT. EXPECT MUCH OF THIS SNOW
WILL MELT TODAY AS THE FRONT WAVERS BACK NORTHWEST AND TEMPS RISE
INTO THE 40S.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 338 AM MDT THU SEP 26 2013
THE COLD FRONT ASSOCIATED WITH THE BROAD UPPER-LEVEL TROUGH
ENCOMPASSING MUCH OF THE NORTHERN INTERMOUNTAIN WEST LAY ALONG A
KBCE-35N KGJT-KEEO-K3MW LINE EARLY THIS MORNING. SOME VIRGA WAS
EVIDENT IN KGJX RADAR IMAGERY RESULTING FROM OVERRUNNING OF THE
FRONT. LITTLE MOISTURE ENTRAINED IN THE SOUTHWEST FLOW WHICH
EXPLAINS WHY MOISTURE WASN/T REACHING THE GROUND.
THE TROUGH IS EXPECTED TO DIG SOUTHWARD IN RESPONSE TO A 125KT JET
PLUNGING SOUTHWARD ON ITS BACK SIDE. THIS WILL CAUSE THE AXIS OF
THE TROUGH TO LOSE SOME OF ITS POSITIVE TILT WHICH...IN TURN...WILL
RESULT IN THE FRONT LIFTING BACK TO THE NORTHWEST AS A WARM FRONT.
BECAUSE SYSTEM DRAWING FROM DRYER AIRMASS TO THE SOUTH CUT POPS
ACROSS ALL BUT THE EASTERN UINTA MOUNTAINS TODAY. IN THIS REGION
INSTABILITY SUPPORTS THE FORMATION OF A FEW EMBEDDED
THUNDERSTORMS.
PRE-FRONTAL SOUTHWEST WINDS WILL CONTINUE TO BE RATHER STRONG ACROSS
THE AREA AGAIN THIS AFTERNOON. A CORE OF 45 KNOT WINDS AT THE 7H
LEVEL OVER SOUTHEAST UTAH AND SOUTHWEST COLORADO APPEARS DURING
THE AFTERNOON AS THE MID-LEVEL AND SURFACE GRADIENTS TIGHTEN WITH
THE APPROACH OF THE TROUGH. GIVEN YESTERDAY/S WINDS...NO REASON
TO BELIEVE WIND ADVISORY FOR LOWER ELEVATIONS OF SOUTHEAST UTAH AND
SOUTHWEST COLORADO WON/T VERIFY. THEREFORE...WILL CONTINUE THE WIND
ADVISORY FROM NOON TO 7 PM. SINCE MODELS WERE IN GOOD AGREEMENT
WITH PLACEMENT OF THE 7H WIND MAX OVER THE ADVISED AREA AND WERE
CONSISTENT WITH PREVIOUS RUNS HAVE NO PLANS TO EXPAND WIND HILITES.
THOUGH MUCH OF THE FORECAST AREA WILL BE IN THE WARM SECTOR AGAIN
TODAY...COOLING AT 7H LEVELS WILL RESULT IN A FEW DEGREES OF
COOLING THIS AFTERNOON. MET GUIDANCE SEEMED TO BE PICKING UP ON
THIS TREND BETTER THAN THE MAV GUIDANCE DESPITE THE FACT THAT THE
GFS SHOWED SIMILAR 7H COOLING.
TONIGHT AND FRIDAY...120+KT JET IS DROPPING DOWN THE CALIFORNIA
COAST THIS MORNING AND WILL HELP CARVE OUT THE WESTERN TROF
TODAY AS IT REFORMS ON THE DOWNSTREAM SIDE OVER THE ROCKIES THIS
EVENING. THIS WILL BEGIN TO PUSH THE TROF EASTWARD SUPPLYING A
STRONG AREA OF ASCENT AND INSTABILITY TO NORTHERN UTAH...WITH THE
TROP FOLD LOWERING TO NEAR 450MB. MODELS STILL WANT TO PUSH
MOISTURE UP THE 315K SURFACE THROUGH TODAY...BRINGING PWATS UP TO
NEAR NORMAL FOR LATE SEPTEMBER. THIS IS LESS THAN WHAT HAS BEEN IN
PLACE LATELY BUT THE DYNAMICS WITH THIS STORM LOOK SUFFICIENT TO
BRING A PERIOD OF MODERATE SNOWFALL TO THE NORTHWEST CWA
OVERNIGHT. A COLD FRONT MOVING THROUGH NORTHEAST UTAH THIS EVENING
APPEARED TO LINK UP WITH THE UPPER ASCENT BY MID LEVEL
FRONTOGENESIS...WITH THE NAM EVEN HINTING AT A COUPLED JET OVER
THIS REGION. MODELS ALSO HINT AT THE DRY CONVEYOR BELT LIFTING
ACROSS THIS REGION WITH PV LOBE PROVIDING INSTABILITY AND HAVE PUT
ISOLATED THUNDERSTORMS IN THE FORECAST. THE INSTABILITY...MOISTURE
AND LIFT ALL POINT TO A FEW HOURS OF MODERATE TO HEAVY SNOWFALL.
IT SHOULD BE NOTED THAT SNOW WAS SEEN TODAY AT 8000 FEET IN THE
EASTERN UINTAS THOUGH DYNAMICS WHERE WEAKER. GIVEN THE ABOVE...FELT
ADVZY LEVEL SNOWS MOST LIKELY TO IMPACT TRAVEL ROUTES WITH HIGHER
AMOUNTS OVER 10000 FEET. MODELS KEEP THE DENDRITIC LAYER SATURATED
UP NORTH SO POPS REMAIN THE HIGHEST HERE. A MOIST SOUTHWEST FLOW
AND INSTABILITY WILL BRING SOME CHANCE OF SNOWFALL TO THE HIGHER
MOUNTAINS IN THE CENTRAL AND SOUTH OVERNIGHT. THERMO PROFILES AND
DRIER ICE LAYER INDICATES HOWEVER THIS WILL BE FAIRLY LIGHT AND
MAINLY ABOVE THE 10000 FT LEVEL. THE FRONT WILL CONTINUE TO
PROGRESS ACROSS THE CWA ON FRIDAY...DRIVEN BY THE PROGRESSIVE TROF
ALOFT. MOISTURE LOOKS TO BE ON THE WAY OUT BUT INSTABILITY RE-
ENFORCED BY COLD AIR ALOFT. THE NORTHERLY FLOW WILL CONTINUE TO
FAVOR THE EASTERN UINTAS THROUGH THE DAY AS COLD AIR FILTERS IN.
SCATTERED SHOWERS ALSO CONTINUE ALONG THE FRONT AND THE HIGHER
TERRAIN OF WESTERN COLORADO. PROFILES OVER MANY VALLEY AREAS WERE
QUITE DRY IN THE LOWER LEVELS SO BACKED OFF ON POPS IN SEVERAL
PLACES. FRIDAY HIGHS WILL FALL BY SOME 10 TO 15 DEGREES BEHIND
THE FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 AM MDT THU SEP 26 2013
FRIDAY NIGHT INTO SATURDAY...CLEARING SKIES IN THE DRIER AIRMASS
WILL SPELL A COLD NIGHT ACROSS MUCH OF THE REGION AND FREEZING
TEMPERATURES WILL BE MORE COMMON ACROSS SOME OF THE LOWER
ELEVATIONS. LOOKS LIKE SOUTHERN FOOTHILLS OF THE SAN JUANS...
NORTHERN PLATEAUS...UINTA BASIN AND UPPER COLORADO MAY ALL BE IN
THREAT OF A SEASON ENDING FREEZE. RIDGING BUILDS IN FOR SATURDAY
AND TEMPERATURES WILL BEGIN A TREND BACK UPWARDS. THE COLD START
AND STRONGER INVERSION WILL KEEP TEMPERATURES ON THE COOL SIDE OF
NORMAL...BUT A DECENT START TO THE WEEKEND SHOULD COMMENCE.
SATURDAY NIGHT TO WEDNESDAY...FLAT ZONAL FLOW PREDOMINATES THROUGH
THE REMAINDER OF THE WEEK AND INTO THE MIDDLE OF THE COMING
WEEK. AS A RESULT...EXPECT DRY AND MILD CONDITIONS THROUGH
WEDNESDAY. TEMPERATURES WILL WARM A BIT RISING TO NEAR NORMAL BY
MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 338 AM MDT THU SEP 26 2013
EXPECT STRONG SOUTHWEST WINDS TO GENERATE SIGNIFICANT MECHANICAL
TURBULENCE AHEAD OF A COLD FRONT ASSOCIATED WITH AN EARLY FALL
STORM CENTERED OVER SOUTH-CENTRAL IDAHO. THE FRONT WILL EXTEND
FROM NEAR KBCE TO KRWL LINE THIS AFTERNOON WHEN WINDS REACH THEIR
PEAK. THE STRONGEST WINDS ARE EXPECTED OVER SOUTHEAST UTAH AND
PORTIONS OF SOUTHWEST COLORADO WHERE SUSTAINED WINDS FROM 20 TO 30
MPH WITH GUSTS TO NEAR 50 MPH ARE ANTICIPATED.
IN ADDITION TO WINDS...SCATTERED LIGHT SHOWERS ARE EXPECTED TO
CONTINUE OVER THE EASTERN UINTA MOUNTAINS THROUGH MUCH OF THE DAY
RESULTING IN AREAS OF MOUNTAIN OBSCURATION. PRECIPITATION IS
UNLIKELY TO AFFECT AIRPORTS WITHIN THE FORECAST AREA UNTIL AFTER
00Z/FRIDAY.
AS THE SYSTEM FINALLY BEGINS TO PUSH ACROSS THE AREA TONIGHT
SHOWERS WILL INCREASE IN COVERAGE WITH A FEW EMBEDDED
THUNDERSTORMS ACROSS NORTHEAST UTAH AND NORTHWEST COLORADO
THROUGH 06Z. AS A RESULT...THERE IS A GOOD CHANCE AIRPORTS NORTH
OF THE I-70 CORRIDOR WILL EXPERIENCE MVFR CIGS AND/OR VSBY IN
SHOWERS THROUGH 12Z. CHANCES DECREASE SOUTH OF I-70 WITH ONLY A
SLIGHT CHANCE FOR THE SOUTHERNMOST AIRPORTS TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR COZ020-021.
FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR
COZ002-008-021>023.
UT...WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR UTZ022-027-029.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY
FOR UTZ023.
&&
$$
UPDATE...JAD
SHORT TERM...NL/15
LONG TERM...15/NL
AVIATION...NL
AREA FORECAST DISCUSSION
NWS MIAMI FL
852 AM EDT THU SEP 26 2013
.UPDATE...
SATELLITE AND OBSERVATIONS FROM THIS MORNING SHOWED A BOUNDARY
ACROSS NORTH FLORIDA. SCATTERED SHOWERS AND A COUPLE THUNDERSTORMS
WERE DEVELOPING ACROSS THE LOCAL GULF WATERS AND MOVING ACROSS
COLLIER...HENDRY...AND GLADES COUNTIES IN THE WESTERLY FLOW. THE
12Z SOUNDING SHOWED SOME DRIER AIR ALOFT...WITH PRECIPITABLE WATER
VALUES DOWN TO AROUND 1.8 INCHES. WATER VAPOR SHOWED MUCH DRIER MID
LEVEL AIR MOVING SOUTHWARD ACROSS THE SOUTHEAST AND INTO NORTH
FLORIDA. MODIFYING THE SOUNDING INDICATED THAT THERE WAS A
POSSIBILITY OF STRONG TO EVEN ISOLATED SEVERE STORMS THIS
AFTERNOON WITH THE MAIN THREAT BEING STRONG/ISOLATED SEVERE
DOWNBURST WINDS. THE LATEST HRRR SHOWS A LINE OF SHOWERS AND
STORMS DEVELOPING ACROSS THE NORTHERN PORTION OF THE REGION BY MID
AFTERNOON AND SLOWLY SLIDING SOUTHEAST. SO STRETCHED THE HIGHER
POPS THAT WERE ACROSS THE EAST BACK TO THE WESTERN PORTIONS OF THE
REGION AS WELL.
DRIER AIR WILL FILTER INTO THE REGION FROM THE NORTH BY THIS
EVENING AS A SHORTWAVE DIVES SOUTH AND LOW PRESSURE DEVELOPS OVER
THE WESTERN ATLANTIC. THIS WILL DRIVE THE DRIER AIR INTO THE
REGION OVERNIGHT TONIGHT INTO THE DAY ON FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 639 AM EDT THU SEP 26 2013/
AVIATION...
VFR CONDITIONS THIS MORNING WITH SOME ISOLATED TO SCATTERED
SHOWERS MOVING ACROSS THE AREA. LATER TODAY, A SURFACE COLD FRONT,
WHICH WILL BE MORE OF JUST A DRY LINE TYPE OF FRONT, WILL BEGIN TO
PUSH INTO SOUTH FLORIDA. THIS WILL ALLOW SHOWERS AND THUNDERSTORMS
TO DEVELOP THIS AFTERNOON. THE FRONTAL PASSAGE IS A LITTLE TRICKY TO
TIME AS IT HAS NOT BEGUN TO MOVE YET. CURRENTLY THINK IT WILL BE
LATER IN THE DAY, AFTER 22Z. BEHIND THE FRONT, CONDITIONS QUIET
DOWN AND SKIES SHOULD CLEAR. THE ONLY EXCEPTION TO VFR TODAY WILL
BE IN ASSOCIATION WITH ANY SHOWERS AND/OR THUNDERSTORMS THAT
AFFECT THE TAF SITES, BRINGING CONDITIONS TO MVFR, AND MAYBE EVEN
BRIEF IFR.
WINDS ARE LIGHT AND VARIABLE THIS MORNING. THEY WILL PICK UP OUT
OF THE WEST AROUND 10 KTS. THERE WILL BE A WIND SHIFT WITH THE
FRONTAL PASSAGE TO NW BETWEEN 5 AND 10 KTS. THEY SHOULD GO LIGHT
AND VARIABLE ONCE AGAIN LATE TONIGHT.
PREV DISCUSSION... /ISSUED 417 AM EDT THU SEP 26 2013/
DISCUSSION...
QUASI-STATIONARY FRONTAL BOUNDARY CONTINUES TO BE DRAPED ACROSS
NORTHERN FLORIDA EARLY THIS MORNING. THIS FRONT IS STILL EXPECTED
TO PUSH TO THE SOUTH THROUGH THE DAY AND INTO THE LAKE OKEECHOBEE
REGION BY THE LATE AFTERNOON TO EARLY EVENING HOURS...AND FURTHER
SOUTH INTO THE MID TO LATE EVENING HOURS. MODEL SOUNDINGS STILL
SHOW PRECIPITABLE WATER AMOUNTS AROUND 2 INCHES ACROSS SOUTH
FLORIDA PRECEDING THE FRONT. AS A RESULT...SCATTERED SHOWERS AND
A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE AREA
BEGINNING DURING THE LATE MORNING HOURS AND COULD BE ENHANCED BY
THE FRONTAL PASSAGE THIS EVENING. CURRENTLY BELIEVE THE BEST
COVERAGE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE FRONT
SHOULD BE ALONG THE EASTERN HALF OF THE CWA INCLUDING THE ATLANTIC
WATERS WITH SLIGHTLY BETTER CONVERGENCE. THIS IS ALSO DEPICTED
FAIRLY WELL BY MODEL REFLECTIVITY.
THIS FRONT WILL EXIT THE AREA BY FRIDAY MORNING USHERING IN MUCH
DRIER AIR INTO SOUTH FLORIDA UNDER NORTH TO NORTHEAST FLOW. THIS WILL
YIELD DEW POINTS IN THE UPPER 60S TO NEAR 70 ACROSS VIRTUALLY THE
ENTIRE AREA. BY LATE SATURDAY...CHANCES FOR A FEW DIURNAL SHOWERS
AND THUNDERSTORMS WILL RETURN AS MOISTURE WRAPS AROUND A PERSISTENT
AREA OF LOW PRESSURE ACROSS THE WESTERN ATLANTIC AND INTO SOUTH
FLORIDA.
DRIER WEATHER RETURNS SUNDAY PERSISTING INTO NEXT WEEK AS THE AREA
OF LOW PRESSURE GETS ABSORBED INTO A BROAD H5 SHORTWAVE AND
RETREATS TO THE NORTHEAST. UPPER RIDGING THEN BUILDS IN WITH A
RETURN TO A MORE EASTERLY FLOW PATTERN.
MARINE...
MODERATE WESTERLY WINDS WILL PREVAIL THROUGH THE DAY BEFORE
TURNING MORE NORTHERLY AS A COLD FRONT CROSSES THROUGH THE REGION
DURING THE LATE AFTERNOON/EARLY EVENING HOURS. SCATTERED SHOWERS
AND THUNDERSTORMS WILL ACCOMPANY THE FRONT ACROSS THE REGIONAL WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 77 87 75 / 50 30 20 20
FORT LAUDERDALE 87 79 87 75 / 50 30 20 20
MIAMI 88 78 88 75 / 50 20 20 20
NAPLES 87 77 88 73 / 50 20 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS GOODLAND KS
816 PM MDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 801 PM MDT FRI SEP 27 2013
JUST COMPLETED AN UPDATE. OVERALL THE FORECAST IS IN PRETTY GOOD
SHAPE SO JUST MADE SOME ADJUSTMENTS BASED ON RECENT TRENDS...
OBSERVATIONS...SATELLITE AND RADAR. MAIN BAND OF INSTABILITY AND
THUNDERSTORMS IS NOW OVER THE CENTRAL PORTION OF THE AREA. HIGHEST
CHANCE OF PRECIPITATION AND INSTABILITY IS IN THE EASTERN HALF.
MAIN UPPER TROUGH AND DECENT AMOUNT OF LIFT STILL TO OUR WEST. SO
SHOULD STILL SEE A DECENT CHANCE IN THE WESTERN HALF OF THE AREA
BUT WILL BE PRIMARILY SHOWERS WITH EMBEDDED THUNDERSTORMS. LEFT
THE PRECIPITATION FORECAST ALONE AFTER 06Z SINCE IT LOOKS GOOD COMPARED
TO REALITY.
HARD TO TELL EXACTLY WHERE THE FRONT IS DUE TO THE THUNDERSTORM
OUTFLOW. BELIEVE IT IS STILL MOSTLY TO THE NORTHWEST OF US. BECAUSE
OF THE OUTFLOW...TEMPERATURES HAVE DROPPED PRETTY FAST ALREADY. DO
EXPECT WIND TO STAY UP AND NOT LET THE TEMPERATURES DROP TOO RAPIDLY.
SO DID ADJUST OVERNIGHT MINS DOWN A FEW DEGREES. AT THIS TIME...UPPER
30S WILL STILL BE POSSIBLE IN THE FAR WEST PORTION OF THE AREA.
WILL CONTINUE TO MONITOR THE WIND AND TEMPERATURE TRENDS. IF WINDS
DROP OFF MORE THAN EXPECTED THEN WILL NEED TO ADJUST MINS DOWN
SOME MORE.
WILL BE KEEPING THE WIND ADVISORY GOING AT THIS TIME. CURRENT
MESOSCALE GUIDANCE WOULD INDICATE WINDS BEHIND THE FRONT MAY NOT
BE AS STRONG AS PREVIOUS INDICATED. HOWEVER...WILL CONTINUE TO
WATCH TRENDS AND LET 00Z GUIDANCE ROLL IN AND ASSESS ONCE AGAIN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1230 PM MDT FRI SEP 27 2013
AS OF NOON MDT/1PM CDT...WV IMAGERY AND RAP H5 ANALYSIS SHOW
POSITIVELY TITLED TROUGH EXTENDING FROM NORTHERN ROCKIES ACROSS
THE GREAT BASIN...WITH ITS BASE NEAR THE BAJA PENINSULA. SW FLOW
IS IN PLACE ACROSS THE PLAINS WITH MID LEVEL MOISTURE PLUME
EXTENDING FROM THE PACIFIC OCEAN AND INTO WESTERN KANSAS OVER OUR
CWA. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING FROM
ABOUT LIMON COLORADO...TO GOODLAND KS...AND NORTH INTO CENTRAL
NEBRASKA. LIGHT TO MODERATE SHOWERS HAVE DEVELOPED ALONG THE
LEADING EDGE OF THIS FRONT...WITH RECENT RADAR RETURNS SHOWING AN
INCREASE IN INTENSITY AND COVERAGE.
GUIDANCE CONTINUES TO INDICATE THIS FRONT LIFTING LATER THIS
AFTERNOON WITH INSTABILITY INCREASING EAST OF THE FRONT OVER
WESTERN/CENTRAL KANSAS. FORECAST SEEMS TO BE ON TRACK REGARDING
COVERAGE...WITH LIGHT TO MODERATE SHOWERS AND ISOLATED
THUNDERSTORMS LIKELY THIS AFTERNOON AND EVENING. HOWEVER THERE HAS
BEEN LITTLE INDICATION OF FRONT LIFTING SO FAR...AND UNTIL IT
DOES THUNDERSTORM COVERAGE (AND SEVERE THREAT) IS IN QUESTION.
LATEST RAP SHOWS 600-900 J/KG OF MUCAPE BY AROUND 00Z IN THE EAST
WHICH ISNT PARTICULARLY IMPRESSIVE...THOUGH IT IS WORTH MENTIONING
THAT THE NAM HAS OVER 1500 J/KG OF MU CAPE IN A SIMILAR AREA. THE
DIFFERENCE SEEMS TO BE TIMING/POSITION OF FRONT WITH NAM
QUICKER/FURTHER NORTH. SHEER IS VERY IMPRESSIVE WITH 0-6KM BULK
SHEER 50KT TO 80KT FROM THE EAST TO THE WEST...AND INCREASING
EFFECTIVE SHEER 40-50KT. IF WE CAN GET A STRONG ENOUGH UPDRAFT
(INSTABILITY DEPENDED) IT COULD QUICKLY BECOME SEVERE CONSIDERING
THE SHEER PROFILES. LCLS ARE STILL ADVERTISED AROUND 9-10KFT
WHICH IS PRETTY HIGH FOR A WIDESPREAD TORNADO THREAT...SO
WIND/HAIL/HEAVY RAIN CONTINUE TO BE THE PRIMARY CONCERNS THIS
AFTERNOON AND EVENING.
VERY DRY/SUBSIDENT AIR MASS WILL BUILD IN FROM THE WEST BEHIND A
COLD FRONT THIS EVENING...AND MODELS SUPPORT SHOWERS/THUNDERSTORMS
QUICKLY ENDING FROM WEST TO EAST IN THE 03-06Z PERIOD. I KEPT SOME
CHANCE POPS LINGERING THROUGH 09Z IN THE EAST TO ACCOUNT FOR A
SLOWER FRONTAL EXIT FOR THOSE LOCATIONS...HOWEVER THIS APPEARS TO
BE MAINLY A AFTERNOON/EVENING EVENT. PRECIP AMOUNTS COULD BE VERY
IMPRESSIVE CONSIDERING THE AMOUNT OF FORCING/MOISTURE
ADVERTISED...AND MODEL QPF FORECASTS CONTINUE TO SUPPORT RAINFALL
AMOUNTS FROM ONE QUARTER OF AN INCH IN THE WEST TO NEAR ONE INCH
IN THE NORTHEAST. WITH POSSIBLE TRAINING/BACK BUILDING OF
SHOWERS/THUNDERSTORMS WE WILL NEED TO MONITOR FOR POSSIBLE FLASH
FLOODING.
REGARDING WIND ADVISORY...THERE SHOULD BE A SHARP INCREASE IN
WINDS IMMEDIATELY BEHIND THE COLD FRONT THIS EVENING. LATEST MODELS
HAVE DECREASED THE WINDS ALOFT SOME FROM PREVIOUS GUIDANCE...AND
SPED UP THE FRONTAL PASSAGE. IM STILL CONFIDENT WE WILL SEE A
BRIEF PERIOD OF NEAR ADVISORY TO ABOVE ADVISORY WIND GUSTS THIS
EVENING THROUGH AROUND MIDNIGHT IN THE EAST...SO I DIDNT SEE A
REASON TO CANCEL THE WIND ADVISORY. IT CURRENTLY RUNS THROUGH
12Z...WHICH MANY BE TOO LONG...HOWEVER IT DOES COVER THE
POSSIBILITY OF A SLOWER FROPA IN THE EAST.
WITH CLEARING SKIES AND A VERY COOL/DRY AIR MASS ADVECTING IN FROM
THE WEST AFTER MIDNIGHT WE WILL LIKELY SEE SOME OF THE COOLER TEMPS
SO FAR THIS MONTH. IF WINDS DECREASE BELOW 10KT (WHICH IS NOT
CURRENTLY EXPECTED) WE COULD COOL TO THE LOW TO MID 30S IN THE
WEST WHICH WOULD PUT US WITHIN FROST ADVISORY CRITERIA
(CONSIDERING TD VALUES AROUND 33F ADVERTISED BY SHORT RANGE MODEL
CONSENSUS). LOWS ARE CURRENTLY EXPECTED TO BE FROM THE UPPER 30S
IN THE WEST TO NEAR 50 IN THE EAST...SO NO ADVISORY IS CURRENTLY
ANTICIPATED.
.LONG TERM...(TOMORROW THROUGH FRIDAY)
ISSUED AT 1237 PM MDT FRI SEP 27 2013
QUIET WEATHER IS EXPECTED THROUGH AT LEAST MID WEEK AS ZONAL FLOW
BECOMES ESTABLISHED ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE
WILL BE SOME EMBEDDED WEAK DISTURBANCES...BUT THE MAIN STORM TRACK
WILL SHIFT NORTHWARD WITH TIME AND LOW LEVEL MOISTURE WILL BE VERY
LIMITED. THE NEXT FRONTAL PASSAGE MAY OCCUR WEDNESDAY NIGHT AS THE
UPPER FLOW BECOMES MORE SOUTHWEST AHEAD OF A SHORTWAVE TROUGH IN
THE NORTHERN ROCKIES. MODELS ARE IN VERY POOR AGREEMENT AT THIS
TIME...THE ECMWF HAS THE FRONT IN THE DAKOTAS WHILE THE GFS PUSHES
IT THROUGH THE LOCAL AREA WITH A CHANCE OF PRECIPITATION...SO
PREFER TO WAIT FOR BETTER MODEL CONSISTENCY BEFORE COMMITTING TO
POPS. FOR THE LATER PART OF THE WEEK...MODEL CONSISTENCY BECOMES
EVEN WORSE WITH THE ECMWF AND GFS COMPLETELY OUT OF PHASE IN THEIR
UPPER PATTERNS BY FRIDAY. GIVEN THE LOW CONFIDENCE...FORECAST WILL
HEDGE TOWARD NEAR NORMAL TEMPERATURES AND NO MENTION OF PRECIPITATION
AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 620 PM MDT FRI SEP 27 2013
INITIAL CONCERNS ARE SHOWERS AND THUNDERSTORMS NEAR BOTH TAF SITES FOR
THE FIRST HOUR OR TWO OF THE TAF PERIOD. SLIGHT REDUCTION OF
VISIBILITY WILL LIKELY OCCUR IN THE HEAVIEST SHOWERS/STORMS...IF
ONE IMPACTS EITHER TERMINAL. ADDITIONALLY...STRONG WINDS WILL RESULT IN
AREAS OF BLOWING DUST RESULTING IN A REDUCED VISIBILITY. A COLD
FRONT WILL MOVE THROUGH THIS EVENING CAUSING WINDS TO SHIFT TO THE
NORTHWEST. STRONG PRESSURE GRADIENT WILL LIKELY RESULT IN A PERIOD
OF 20 TO 30 KT WINDS WITH GUSTS NEAR 40 KTS IMMEDIATELY BEHIND THE
COLD FRONT. SOME LOW STRATUS MAY OCCUR OVERNIGHT BEHIND THE
FRONT...ESPECIALLY AT GLD. THIS MAY REDUCE CEILINGS TO MVFR
CATEGORY. WINDS WILL SUBSIDE TOWARD DAWN AND SKIES WILL CLEAR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 5 AM MDT /6 AM CDT/ SATURDAY FOR KSZ001>004-
013>016-027>029-041-042.
CO...WIND ADVISORY UNTIL 5 AM MDT SATURDAY FOR COZ090>092.
NE...WIND ADVISORY UNTIL 5 AM MDT /6 AM CDT/ SATURDAY FOR NEZ079>081.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
635 PM MDT FRI SEP 27 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1230 PM MDT FRI SEP 27 2013
AS OF NOON MDT/1PM CDT...WV IMAGERY AND RAP H5 ANALYSIS SHOW
POSITIVELY TITLED TROUGH EXTENDING FROM NORTHERN ROCKIES ACROSS
THE GREAT BASIN...WITH ITS BASE NEAR THE BAJA PENINSULA. SW FLOW
IS IN PLACE ACROSS THE PLAINS WITH MID LEVEL MOISTURE PLUME
EXTENDING FROM THE PACIFIC OCEAN AND INTO WESTERN KANSAS OVER OUR
CWA. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING FROM
ABOUT LIMON COLORADO...TO GOODLAND KS...AND NORTH INTO CENTRAL
NEBRASKA. LIGHT TO MODERATE SHOWERS HAVE DEVELOPED ALONG THE
LEADING EDGE OF THIS FRONT...WITH RECENT RADAR RETURNS SHOWING AN
INCREASE IN INTENSITY AND COVERAGE.
GUIDANCE CONTINUES TO INDICATE THIS FRONT LIFTING LATER THIS
AFTERNOON WITH INSTABILITY INCREASING EAST OF THE FRONT OVER
WESTERN/CENTRAL KANSAS. FORECAST SEEMS TO BE ON TRACK REGARDING
COVERAGE...WITH LIGHT TO MODERATE SHOWERS AND ISOLATED
THUNDERSTORMS LIKELY THIS AFTERNOON AND EVENING. HOWEVER THERE HAS
BEEN LITTLE INDICATION OF FRONT LIFTING SO FAR...AND UNTIL IT
DOES THUNDERSTORM COVERAGE (AND SEVERE THREAT) IS IN QUESTION.
LATEST RAP SHOWS 600-900 J/KG OF MUCAPE BY AROUND 00Z IN THE EAST
WHICH ISNT PARTICULARLY IMPRESSIVE...THOUGH IT IS WORTH MENTIONING
THAT THE NAM HAS OVER 1500 J/KG OF MU CAPE IN A SIMILAR AREA. THE
DIFFERENCE SEEMS TO BE TIMING/POSITION OF FRONT WITH NAM
QUICKER/FURTHER NORTH. SHEER IS VERY IMPRESSIVE WITH 0-6KM BULK
SHEER 50KT TO 80KT FROM THE EAST TO THE WEST...AND INCREASING
EFFECTIVE SHEER 40-50KT. IF WE CAN GET A STRONG ENOUGH UPDRAFT
(INSTABILITY DEPENDED) IT COULD QUICKLY BECOME SEVERE CONSIDERING
THE SHEER PROFILES. LCLS ARE STILL ADVERTISED AROUND 9-10KFT
WHICH IS PRETTY HIGH FOR A WIDESPREAD TORNADO THREAT...SO
WIND/HAIL/HEAVY RAIN CONTINUE TO BE THE PRIMARY CONCERNS THIS
AFTERNOON AND EVENING.
VERY DRY/SUBSIDENT AIR MASS WILL BUILD IN FROM THE WEST BEHIND A
COLD FRONT THIS EVENING...AND MODELS SUPPORT SHOWERS/THUNDERSTORMS
QUICKLY ENDING FROM WEST TO EAST IN THE 03-06Z PERIOD. I KEPT SOME
CHANCE POPS LINGERING THROUGH 09Z IN THE EAST TO ACCOUNT FOR A
SLOWER FRONTAL EXIT FOR THOSE LOCATIONS...HOWEVER THIS APPEARS TO
BE MAINLY A AFTERNOON/EVENING EVENT. PRECIP AMOUNTS COULD BE VERY
IMPRESSIVE CONSIDERING THE AMOUNT OF FORCING/MOISTURE
ADVERTISED...AND MODEL QPF FORECASTS CONTINUE TO SUPPORT RAINFALL
AMOUNTS FROM ONE QUARTER OF AN INCH IN THE WEST TO NEAR ONE INCH
IN THE NORTHEAST. WITH POSSIBLE TRAINING/BACK BUILDING OF
SHOWERS/THUNDERSTORMS WE WILL NEED TO MONITOR FOR POSSIBLE FLASH
FLOODING.
REGARDING WIND ADVISORY...THERE SHOULD BE A SHARP INCREASE IN
WINDS IMMEDIATELY BEHIND THE COLD FRONT THIS EVENING. LATEST MODELS
HAVE DECREASED THE WINDS ALOFT SOME FROM PREVIOUS GUIDANCE...AND
SPED UP THE FRONTAL PASSAGE. IM STILL CONFIDENT WE WILL SEE A
BRIEF PERIOD OF NEAR ADVISORY TO ABOVE ADVISORY WIND GUSTS THIS
EVENING THROUGH AROUND MIDNIGHT IN THE EAST...SO I DIDNT SEE A
REASON TO CANCEL THE WIND ADVISORY. IT CURRENTLY RUNS THROUGH
12Z...WHICH MANY BE TOO LONG...HOWEVER IT DOES COVER THE
POSSIBILITY OF A SLOWER FROPA IN THE EAST.
WITH CLEARING SKIES AND A VERY COOL/DRY AIR MASS ADVECTING IN FROM
THE WEST AFTER MIDNIGHT WE WILL LIKELY SEE SOME OF THE COOLER TEMPS
SO FAR THIS MONTH. IF WINDS DECREASE BELOW 10KT (WHICH IS NOT
CURRENTLY EXPECTED) WE COULD COOL TO THE LOW TO MID 30S IN THE
WEST WHICH WOULD PUT US WITHIN FROST ADVISORY CRITERIA
(CONSIDERING TD VALUES AROUND 33F ADVERTISED BY SHORT RANGE MODEL
CONSENSUS). LOWS ARE CURRENTLY EXPECTED TO BE FROM THE UPPER 30S
IN THE WEST TO NEAR 50 IN THE EAST...SO NO ADVISORY IS CURRENTLY
ANTICIPATED.
.LONG TERM...(TOMORROW THROUGH FRIDAY)
ISSUED AT 1237 PM MDT FRI SEP 27 2013
QUIET WEATHER IS EXPECTED THROUGH AT LEAST MID WEEK AS ZONAL FLOW
BECOMES ESTABLISHED ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE
WILL BE SOME EMBEDDED WEAK DISTURBANCES...BUT THE MAIN STORM TRACK
WILL SHIFT NORTHWARD WITH TIME AND LOW LEVEL MOISTURE WILL BE VERY
LIMITED. THE NEXT FRONTAL PASSAGE MAY OCCUR WEDNESDAY NIGHT AS THE
UPPER FLOW BECOMES MORE SOUTHWEST AHEAD OF A SHORTWAVE TROUGH IN
THE NORTHERN ROCKIES. MODELS ARE IN VERY POOR AGREEMENT AT THIS
TIME...THE ECMWF HAS THE FRONT IN THE DAKOTAS WHILE THE GFS PUSHES
IT THROUGH THE LOCAL AREA WITH A CHANCE OF PRECIPITATION...SO
PREFER TO WAIT FOR BETTER MODEL CONSISTENCY BEFORE COMMITTING TO
POPS. FOR THE LATER PART OF THE WEEK...MODEL CONSISTENCY BECOMES
EVEN WORSE WITH THE ECMWF AND GFS COMPLETELY OUT OF PHASE IN THEIR
UPPER PATTERNS BY FRIDAY. GIVEN THE LOW CONFIDENCE...FORECAST WILL
HEDGE TOWARD NEAR NORMAL TEMPERATURES AND NO MENTION OF PRECIPITATION
AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 620 PM MDT FRI SEP 27 2013
INITIAL CONCERNS ARE SHOWERS AND THUNDERSTORMS NEAR BOTH TAF SITES FOR
THE FIRST HOUR OR TWO OF THE TAF PERIOD. SLIGHT REDUCTION OF
VISIBILITY WILL LIKELY OCCUR IN THE HEAVIEST SHOWERS/STORMS...IF
ONE IMPACTS EITHER TERMINAL. ADDITIONALLY...STRONG WINDS WILL RESULT IN
AREAS OF BLOWING DUST RESULTING IN A REDUCED VISIBILITY. A COLD
FRONT WILL MOVE THROUGH THIS EVENING CAUSING WINDS TO SHIFT TO THE
NORTHWEST. STRONG PRESSURE GRADIENT WILL LIKELY RESULT IN A PERIOD
OF 20 TO 30 KT WINDS WITH GUSTS NEAR 40 KTS IMMEDIATELY BEHIND THE
COLD FRONT. SOME LOW STRATUS MAY OCCUR OVERNIGHT BEHIND THE
FRONT...ESPECIALLY AT GLD. THIS MAY REDUCE CEILINGS TO MVFR
CATEGORY. WINDS WILL SUBSIDE TOWARD DAWN AND SKIES WILL CLEAR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 5 AM MDT /6 AM CDT/ SATURDAY FOR KSZ001>004-
013>016-027>029-041-042.
CO...WIND ADVISORY UNTIL 5 AM MDT SATURDAY FOR COZ090>092.
NE...WIND ADVISORY UNTIL 5 AM MDT /6 AM CDT/ SATURDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
649 PM CDT Fri Sep 27 2013
.SHORT TERM...(This Evening through Saturday)
Issued at 252 PM CDT FRI SEP 27 2013
Tonight through Saturday...
Analysis of the water vapor imagery at 19z depicts the potent
shortwave trough axis rotating through southern Wyoming. An embedded
wave and mid level jet streak within the mean flow was lifting
northward into western Kansas. Looking at the surface, the potent
cold front was oriented southwest to northeast from eastern Colorado
through northwest Kansas, through central and northern Nebraska.
Observations noted 30 degree F temp differences between the
boundaries with upper 40s in northeast Colorado. The surface trough
undergoing lee cyclogenesis over southern Colorado continued to
provide strong southerly winds between 15 and 25 mph with gusts over
30 mph during the current peak heating hours. In turn gulf moisture
streaming northward in advance of the sfc trough has brought
dewpoint temperatures into the low 60s. The aforementioned mid level
wave in combination with the surface front has continued to generate
elevated showers lifting northward across western Kansas.
As the upper wave lifts northeastward into the northern plains,
expect the lee surface trough and frontal boundary to quickly usher
eastward towards northeast Kansas. A line of numerous showers and
thunderstorms are likely to develop in vicinity and along the
boundary during the evening and overnight hours. Consistency between
the latest runs of the 3 km HRRR peg the edge of the precip and
front entering north central areas after 07z, impacting much of east
central areas(including Topeka) after 09z. While the highest
probabilities of severe storms reside towards western and central
Kansas, expect the instability gradient to drop steadily eastward
with only a few hundred j/kg of ML cape over north central areas
around 06z. However, strong effective shear values over 50 kts may
still allow for strong gusty winds from 40 to 50 mph. Locally heavy
rain is likely with the heavier showers as pwat values range from
1.25 to 1.9 inches. QPF values did not deviate much from previous
forecast based on fast track of the front ranging from 0.30 to three
quarters of an inch. Precipitation is expected to end Saturday
afternoon with cloud cover quickly exiting southeast as a drier and
cooler airmass settles in.
Temperatures tonight depend on thickness of cloud cover and showers
with lowest readings over north central areas where cool advection
behind the front will be filtering southward. Further east, lows in
the upper 60s appear to be more common. Expect temps to hover in the
60s for much of Saturday afternoon before a gradual warmup as the
clouds thin, topping out in the low 70s. Northerly winds remain
gusty through the period as the h85 shortwave trough continues to
impact the region before exiting Saturday evening.
.LONG TERM...(Saturday Night through Friday)
Issued at 252 PM CDT FRI SEP 27 2013
As skies clear out and winds settle down behind the front on
Saturday night, overnight lows into Sunday morning are expected to
drop into the lower to middle 40s. Will need to monitor for fog
potential, but air mass is quite dry and therefore fog potential
could be limited to low spots. Sunday forecast to be sunny with
highs in the lower to middle 70s and light south winds. Lows
overnight into Monday should be a few degrees warmer as southerly
winds continue. Thermal ridge out ahead of the next approaching
trof expected to bring highs Monday through Wednesday back up
toward 80 and then lows only falling into the 50s to near 60 by
Thursday morning.
While the sensible weather forecast for Thurs/Fri remains similar
to that of mid week, the speed of an upper trof advancing eastward
into the plains will be the driver of true timing of rain chances
and colder air. Was backing off on progressive solutions as
several ensemble members along with the 00z ECMWF showing a slower
trend, however 12z runs are now coming in slightly faster. Opted
to keep slight chances for rain Thur/Fri, with timing chances too
uncertain to make large changes to a consensus forecast this far
out.
&&
.AVIATION...(For the 00Z TAFs through 00Z Saturday Evening)
Issued at 649 PM CDT FRI SEP 27 2013
For the 00z TAFs, gusty southeasterly winds will continue into the
early evening hours before diminishing some overnight. With model
soundings showing modest wind speeds just above the surface, will
need to monitor the potential for llws this evening. Main focus is
on the timing of the approaching cold front. Most of the
precipitation is expected to be focused along and behind the front,
with short-range models showing showers and possibly a few isolated
thunderstorms moving into the TAF sites between 09-11z. Post-frontal
showers will continue through much of the morning hours with
conditions drying out by the afternoon. With this precipitation,
could see cigs drop down to MVFR conditions for a few hours in the
morning. With the frontal passage, winds will veer to the northwest
and persist through the remainder of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Bowen
LONG TERM...67
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS TOPEKA KS
646 PM CDT Fri Sep 27 2013
.SHORT TERM...(This Evening through Saturday)
Issued at 252 PM CDT FRI SEP 27 2013
Tonight through Saturday...
Analysis of the water vapor imagery at 19z depicts the potent
shortwave trough axis rotating through southern Wyoming. An embedded
wave and mid level jet streak within the mean flow was lifting
northward into western Kansas. Looking at the surface, the potent
cold front was oriented southwest to northeast from eastern Colorado
through northwest Kansas, through central and northern Nebraska.
Observations noted 30 degree F temp differences between the
boundaries with upper 40s in northeast Colorado. The surface trough
undergoing lee cyclogenesis over southern Colorado continued to
provide strong southerly winds between 15 and 25 mph with gusts over
30 mph during the current peak heating hours. In turn gulf moisture
streaming northward in advance of the sfc trough has brought
dewpoint temperatures into the low 60s. The aforementioned mid level
wave in combination with the surface front has continued to generate
elevated showers lifting northward across western Kansas.
As the upper wave lifts northeastward into the northern plains,
expect the lee surface trough and frontal boundary to quickly usher
eastward towards northeast Kansas. A line of numerous showers and
thunderstorms are likely to develop in vicinity and along the
boundary during the evening and overnight hours. Consistency between
the latest runs of the 3 km HRRR peg the edge of the precip and
front entering north central areas after 07z, impacting much of east
central areas(including Topeka) after 09z. While the highest
probabilities of severe storms reside towards western and central
Kansas, expect the instability gradient to drop steadily eastward
with only a few hundred j/kg of ML cape over north central areas
around 06z. However, strong effective shear values over 50 kts may
still allow for strong gusty winds from 40 to 50 mph. Locally heavy
rain is likely with the heavier showers as pwat values range from
1.25 to 1.9 inches. QPF values did not deviate much from previous
forecast based on fast track of the front ranging from 0.30 to three
quarters of an inch. Precipitation is expected to end Saturday
afternoon with cloud cover quickly exiting southeast as a drier and
cooler airmass settles in.
Temperatures tonight depend on thickness of cloud cover and showers
with lowest readings over north central areas where cool advection
behind the front will be filtering southward. Further east, lows in
the upper 60s appear to be more common. Expect temps to hover in the
60s for much of Saturday afternoon before a gradual warmup as the
clouds thin, topping out in the low 70s. Northerly winds remain
gusty through the period as the h85 shortwave trough continues to
impact the region before exiting Saturday evening.
.LONG TERM...(Saturday Night through Friday)
Issued at 252 PM CDT FRI SEP 27 2013
As skies clear out and winds settle down behind the front on
Saturday night, overnight lows into Sunday morning are expected to
drop into the lower to middle 40s. Will need to monitor for fog
potential, but air mass is quite dry and therefore fog potential
could be limited to low spots. Sunday forecast to be sunny with
highs in the lower to middle 70s and light south winds. Lows
overnight into Monday should be a few degrees warmer as southerly
winds continue. Thermal ridge out ahead of the next approaching
trof expected to bring highs Monday through Wednesday back up
toward 80 and then lows only falling into the 50s to near 60 by
Thursday morning.
While the sensible weather forecast for Thurs/Fri remains similar
to that of mid week, the speed of an upper trof advancing eastward
into the plains will be the driver of true timing of rain chances
and colder air. Was backing off on progressive solutions as
several ensemble members along with the 00z ECMWF showing a slower
trend, however 12z runs are now coming in slightly faster. Opted
to keep slight chances for rain Thur/Fri, with timing chances too
uncertain to make large changes to a consensus forecast this far
out.
.AVIATION...(For the 18Z TAFs through 18Z Saturday
Afternoon) Issued at 1227 PM CDT FRI SEP 27 2013
VFR at KTOP/KFOE/KMHK with gusty south winds thru afternoon. Primary
focus is a cold front and line of showers/isolated thunder impacting sites
aft 07z at KMHK and 09z at KTOP/KFOE. Cigs lower to MVFR through the
early morning. Instability is limited with low confidence and only
vcts mentioned. Gusty south winds back to the southeast in the
evening before gradually veering to the west and northwest with
the fropa.
&&
.AVIATION...(For the 00Z TAFs through 00Z Saturday Evening)
Issued at 645 PM CDT FRI SEP 27 2013
For the 00z TAFs, gusty southeasterly winds will continue into the
early evening hours before diminishing some overnight. With model
soundings showing modest wind speeds just above the surface, will
need to monitor the potential for llws this evening. Main focus is
on the timing of the approaching cold front. Most of the
precipitation is expected to be focused along and behind the front,
with short-range models showing showers and possibly a few isolated
thunderstorms moving into the TAF sites between 09-11z. Post-frontal
showers will continue through much of the morning hours with
conditions drying out by the afternoon. With this precipitation,
could see cigs drop down to MVFR conditions for a few hours in the
morning. With the frontal passage, winds will veer to the northwest
and persist through the remainder of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Bowen
LONG TERM...67
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS CARIBOU ME
631 PM EDT THU SEP 26 2013
.SYNOPSIS...
LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY MOVE EAST THIS
EVENING AND ALLOW A LARGE RIDGE OF HIGH PRESSURE TO BUILD INTO
OUR REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
631 PM UPDATE... THERE ARE A COUPLE OF BREAKS IN THE CLOUDS IN
PARTS OF AROOSTOOK AND PISCATAQUIS COUNTIES. OTHERWISE...MOST
AREAS ARE STILL OVC035. THE TIME HEIGHT FROM BOTH THE NAM AND GFS
INDICATE A LOT OF MOISTURE BELOW 750 MILLIBARS TONIGHT...AND IT
MAY BE VERY TOUGH TO GET RID OF THE CLOUDS UNTIL VERY LATE TONIGHT
OR EARLY FRIDAY MORNING. THE HRRR APPEARS WAY TOO QUICK TO ERODE
THE CLOUDS THIS EVENING. THE MAIN UPDATE WAS TO SLOW THE CLEARING
BY A FEW HOURS THIS EVENING ACROSS THE NORTHERN HALF OF THE CWA.
PREVIOUS DISCUSSION...
HIGH PRESSURE BUILDS OVERNIGHT WITH CLEARING SKIES ADVECTING FROM
THE CROWN OF MAINE SOUTHWARD TOWARDS BANGOR BY LATE NIGHT. LOWS
WILL RANGE FROM NEAR 40F IN THE SJV TO THE UPPER 40S FOR DOWN EAST
AND BANGOR WHERE CLOUDS WILL LINGER. THE LAST OF THE CLOUDS WILL MOVE
SOUTHWARD OUT OF THE FORECAST AREA FRIDAY MORNING. THIS WILL
PRODUCE A SUNNY DAY WITH SOME FAIR WEATHER CUMULUS AND HIGHS
REACHING THE UPPER 60S TO LOW 70S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
DRY WEATHER PATTERN AND MILDER RIGHT THROUGH THIS TERM.
A LARGE RIDGE OF HIGH PRES WILL MOVE INTO THE CWA OVER THE WEEKEND
PROVIDING A WELL NEEDED STRETCH OF DRY WEATHER AND ABOVE NORMAL
TEMPERATURES. DECIDED ON A BLEND OF THE EMCWFMOS/BCMOS FOR MIN
TEMPERATURES FRIDAY NIGHT AND AGAIN SATURDAY NIGHT. FRIDAY NIGHT
WILL BE THE COOLEST OF THE 2 W/OVERNIGHT LOWS EXPECTED IN THE
UPPER 30S TO LOWER 40S. DAYTIME HIGHS WILL BE ABOVE NORMAL FOR
LATE SEPTEMBER. DECIDED ON A BLEND OF THE BCMOS AND GMOS SHOWING
READINGS EXPECTED TO HIT THE 70S FOR JUST ABOUT THE ENTIRE CWA.
THE COAST COULD BE A FEW DEGREES COOLER GIVEN THE POTENTIAL FOR A
SEA BREEZE AND WEAK ON SHORE WIND.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE FCST LOOKS TO CONTINUE ON THE DRY SIDE W/THE ONLY DISRUPTION
BEING A SUB-TROPICAL LOW MOVING UP FROM THE BERMUDA AREA GIVING A
GLANCING BLOW MAINLY TO THE IMMEDIATE COAST/OUTER ISLAND. THE
TIME FRAME FOR THIS WOULD BE MONDAY NIGHT INTO TUESDAY. THE 12Z
ECWMF RUN MATCHED UP W/ITS 00Z RUN OF BRINGING THE SUB-TROPICAL
SYSTEM MME AND PASSING THE EAST OF NOVA SCOTIA. IF SCENARIO WERE
TO TAKE PLACE, THE OUTER BANDS OF PRECIPITATION WOULD SKIRT THE
IMMEDIATE COAST AND THE OUTER ISLANDS. THE 12Z RUN OF THE GFS AND
GEM GLOBAL KEEP THE LOW FURTHER SOUTH AND EAST W/THE NEW ENGLAND
REGION STAYING ON THE DRY SIDE. ATTM, DECIDED TO USE A BLEND OF ALL
3 AS SOME THE GFS ENSEMBLE MEMBERS SHOW A TRACK SIMILAR TO THE
ECMWF. THEREFORE, KEPT THE MAJORITY OF THE CWA DRY INTO TUESDAY AND
HUNG ON TO A 20-30% CHC FOR RAIN ALONG THE IMMEDIATE COAST AND THE
OUTER ISLANDS MONDAY NIGHT INTO TUESDAY. WEDNESDAY AND THURSDAY
APPEAR TO BE DRY AS HIGH PRES RE-ESTABLISHES ITSELF OVER THE
NORTHEASTERN US.
DAYTIME TEMPERATURES WILL CONTINUE TO BE AOA NORMAL. DECIDED TO
BLEND THE BCMOS INCLUDING THE ECMWF FOR THE OVERNIGHT LOWS AS THE
GMOS TEMPERATURES LOOK TO BE TOO COLD GIVEN THE ESTABLISHED
PATTERN IN PLACE.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: MOSTLY OVC035 AT THE TAF SITES THIS EVENING. THE
NORTHERN TAF SITES SHOULD REMAIN VFR WITH THE CLOUDS BECOMING SCT
OVERNIGHT. KBGR AND KBHB MAY GO BACK DOWN TO MVFR FOR A TIME LATER
THIS EVENING BEFORE LIFTING TO VFR EARLY MONDAY MORNING.
SHORT TERM: VFR RUNNING RIGHT INTO MONDAY.
&&
.MARINE...
NEAR TERM: LIGHT WINDS UNDER 15 KTS AND SEAS MOSTLY AROUND 2 FT ON
THE COASTAL WATERS AND 1 FOOT ON THE INTRA-COASTAL WATERS THROUGH
THE PERIOD.
SHORT TERM: NO HEADLINES EXPECTED. AS WINDS ADD SEAS ARE FCST TO
REMAIN BELOW SCA THRESHOLDS. WE AREA TALKING WINDS OF 10 KTS RIGHT
INTO MONDAY. THERE IS THE POTENTIAL FOR A SWELL TO BE GENERATED BY
MONDAY FROM THE LOW APCHG FROM THE S. ADJUSTED THE WAVE HEIGHTS TO
ACCOUNT FOR THIS POSSIBILITY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CB/MCW
SHORT TERM...FITZSIMMONS
LONG TERM...FITZSIMMONS
AVIATION...CB/MCW/FITZSIMMONS
MARINE...CB/MCW/FITZSIMMONS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
138 PM EDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1249 PM EDT THU SEP 26 2013
CHANGES THIS HOUR: FOG HAS FINALLY GIVEN WAY DOWN TOWARDS KMNM THIS
HOUR...WITH JUST A FEW CIRRUS FILTERING THE SUNSHINE. WILL EXTEND FOG
MENTION OVER NORTHERN GREEN BAY...BUT OTHERWISE LITTLE CHANGES ARE
NEEDED TO THE AFTERNOON FORECAST. TEMPERATURES RUNNING A LITTLE
BEHIND PREVIOUS FORECAST GIVEN THIS LATE CLEAR OUT...BUT DO EXPECT
THEM TO REBOUND NICELY WITH NEARLY FULL SUN THIS AFTERNOON.
UPDATE ISSUED AT 937 AM EDT THU SEP 26 2013
CHANGES THIS HOUR: WILL EXTEND FOG ANOTHER HOUR GIVEN EARLY MORNING
VISIBLE SATELLITE TRENDS WHICH SHOW A /VERY/ SLOW BURNING OFF PROCESS
BEGINNING. OTHERWISE...HAVE LOWERED AFTERNOON DEWPOINTS A TAD BASED
ON DRY AIRMASS CENTERING ITSELF OVERHEAD THIS AFTERNOON...WITH NO
OTHER SIGNIFICANT CHANGES NECESSARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT THU SEP 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A STAGNANT UPR
FLOW OVER THE CONUS WITH UPR RDG OVER THE GREAT LKS SANDWICHED BTWN
SLOW MOVING CLOSED LO OFF THE CANADIAN MARITIMES AND A DEEPENING
TROF OVER THE WRN STATES. SFC HI PRES REMAINS ANCHORED IN QUEBEC...
WITH RDG AXIS EXTENDING SWWD INTO THE UPR LKS. ALTHOUGH ABUNDANT MID
LVL DRY AIR ABOVE SHARP SUBSIDENCE INVRN NEAR H9 SHOWN ON THE 00Z
GRB/APX RAOBS IS BRINGING DRY WX...EFFICIENT NOCTURNAL COOLING HAS
ALLOWED FOG TO FORM OVER MAINLY THE SCENTRAL COUNTIES AND THE
KEWEENAW WHERE LGT E-SE FLOW ARND SFC HI PRES IS UPSLOPING OFF THE
LKS. BUT IN CONTRAST TO LAST NGT...ADVECTION OF VERY DRY NEAR SFC
AIRMASS SHOWN ON THE 00Z APX RAOB /PWAT 0.30 INCH/ IS TENDING TO
LIMIT THE COVERAGE OF THE THICKER FOG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOG TRENDS AND TEMPS AS
WELL AS THE POTENTIAL FOR MORE FOG FORMATION TNGT.
EARLY THIS MRNG/TDAY...MAIN LIMITATION TO WDSPRD DENSE FOG EARLY
THIS MRNG WL BE THE ADVECTION OF THE DRIER LLVL AIR SHOWN ON THE 00Z
APX RAOB. SHORT TERM MODEL FCSTS SHOW THIS DRIER H95-9 AIR BLO THE
SUBSIDENCE INVRN OVERSRREADING UPR MI EARLY THIS MRNG...COUNTERING
TO SOME EXTENT THE IMPACT OF NOCTURNAL COOLING UNDER THE MID LVL DRY
AIR. WL MAINTAIN A MENTION OF AREAS OF FOG UNTIL 13Z OVER THE
SCENTRAL WITH FVRBL UPSLOPE WIND COMPONENT. AWAY FM THIS
AREA...EXPECT NOTHING MORE THAN PATCHY FOG. DOWNSLOPE NATURE OF THE
LLVL FLOW WL LIKELY KEEP MUCH FOG FM DVLPG NEAR LK SUP AND OVER THE
FAR W ARND IWD. ISSUED SPS FOR THE SCENTRAL COUNTIES TO COVER
LOCALLY DENSE FOG IN THIS AREA THRU SUNRISE...BUT AN ADVY WL NOT BE
NECESSARY. ONCE ANY FOG BURNS OFF SOON AFTER SUNRISE...EXPECT
MOSUNNY SKIES. WITH H85 TEMPS FCST UP TO 17C OVER THE W...MAX TEMPS
THERE SHOULD TOP OUT IN THE 70S AWAY FM SOME MODERATION ON MAINLY
THE E SIDE OF THE KEWEENAW IN LLVL SE FLOW. THIS SE FLOW WL TEND TO
LIMIT THE DIURNAL TEMP RISE OVER THE SE COUNTIES.
TNGT...THE UPR RDG AXIS IS FCST TO DRIFT ONLY SLOWLY TO THE E...WITH
SFC HI OVER QUEBEC DRIFTING S INTO NEW ENGLAND. WITH FALLING MSLP IN
THE PLAINS ASSOCIATED WITH SHRTWV LIFTING OUT OF THE WRN TROF...THE
PRES GRADIENT/SLY FLOW IS PROGGED TO SHARPEN OVER MAINLY WRN UPR MI.
THIS INCRSG S WIND IN CONCERT WITH FCST INCRSG PWAT WL RESTRICT THE
DIURNAL TEMP FALL IN THIS AREA...SO TENDED TOWARD THE WARM SIDE OF
GUIDANCE FOR MIN TEMPS OVER THE FAR W FM IWD INTO THE KEWEENAW. A
FLATTER PRES GRADIENT/PWAT FCST AOB 0.50 INCH CLOSER TO THE SFC HI
TO THE E WL SUPPORT LOWER TEMPS OVER THE INTERIOR E HALF...AND FCST
LO TEMPS CLOSER TO THE LO END OF GUIDANCE IN THIS AREA. BUT SOMEWHAT
STRONGER H925 WINDS UP TO 20KTS FCST IN THIS AREA WL LIKELY KEEP THE
LOWS A BIT HIER THAN OBSVD THIS MRNG. WITH THE S WIND OFF LK MI...
EXPECT MORE FOG TO FORM IN THIS AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 406 AM EDT THU SEP 26 2013
FRIDAY WILL BE THE LAST COMPLETELY DRY DAY ACROSS THE CWA AS THE
HIGH PRESSURE RIDGE THAT HAS BEEN INFLUENCING OUR WEATHER SLIDES
SOUTHEAST INTO THE ATLANTIC STATES. AT THE SAME TIME...THE UPPER
TROUGH CURRENTLY OVER THE WESTERN CONUS WILL EJECT OUT OF THE
ROCKIES AND INTO THE CENTRAL AND NORTHERN PLAINS. A SHORTWAVE
EXITING THIS UPPER TROUGH WILL MOVE NORTHEAST THROUGH THE CANADIAN
PRAIRIES WITH AN ASSOCIATED SURFACE LOW THAT LEAVE AN ELONGATED
SURFACE TROUGH STRETCHING SOUTH THROUGH MINNESOTA AND INTO THE
CENTRAL PLAINS. SINCE THAT WILL BE THE MAIN FOCUS OF THE
PRECIPITATION ON FRIDAY AND THE AREA STILL UNDER THE DRY AIR OF THE
HIGH...SHOULD SEE ANOTHER MOSTLY SUNNY DAY ACROSS THE CWA. LATE IN
THE AFTERNOON...COULD SEE SOME MID-HIGH CLOUDS AFFECTING WESTERN
UPPER MICHIGAN. WITH THE SUNSHINE...SHOULD SEE ANOTHER DAY OF ABOVE
NORMAL HIGHS WITH TEMPERATURES IN THE UPPER 60S TO MIDDLE 70S. IT
SHOULD BE A LITTLE BREEZY ON FRIDAY DUE TO THE INCREASING PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING TROUGH...ESPECIALLY
OVER THE WEST WHERE THERE COULD BE GUSTS TO 25-30MPH. EXPECT BREEZY
CONDITIONS TO CONTINUE AT TIMES FRIDAY NIGHT INTO SATURDAY UNTIL
THE FRONT MOVES THROUGH.
THIS DRY AIR WILL REMAIN THROUGH FRIDAY NIGHT AND INTO SATURDAY
MORNING...WITH ONLY A FEW SHOWERS BRUSHING FAR WESTERN LAKE
SUPERIOR DURING THAT TIME. THEN...AS THE UPPER TROUGH EJECTS OUT OF
THE FOUR CORNERS REGION FRIDAY NIGHT...IT PULLS THE ENTIRE UPPER
TROUGH WITH IT AND THROUGH THE UPPER GREAT LAKES REGION THROUGH
SUNDAY. IN ADDITION...A SECONDARY LOW WILL DEVELOP ALONG THE TROUGH
NEAR WESTERN LAKE SUPERIOR AND THE MN ARROWHEAD AS THE RIGHT REAR
OF THE UPPER JET SLIDES NORTHEAST THROUGH THE AREA. THIS WILL ALLOW
A LINE OF SHOWERS ORIENTATED NORTH-SOUTH ALONG AND BEHIND THE
TROUGH TO MOVE EAST-NORTHEAST ACROSS UPPER MICHIGAN. AS HAS BEEN THE
CASE OVER THE LAST SEVERAL NIGHT...THE GFS REMAINS THE FASTEST WITH
THE ARRIVAL OF THE TROUGH/SHOWERS...WHILE THE GEM/ECMWF ARE MORE
CONSISTENT WITH THE SLOWER ARRIVAL. THE NAM ALSO FOLLOWS ALONG WITH
THE FASTER ARRIVAL SHOWN IN THE GFS. SINCE THERE IS AN EVEN SPLIT IN
ARRIVAL TIMES AND ONLY 50-75MI SPREAD...WILL SPLIT THE DIFFERENCE
AT THIS POINT AND HAVE THE WESTERN THIRD/HALF OF UPPER MICHIGAN
SEEING RAIN BY SUNSET AND THEN IT SPREADING ACROSS THE REST OF THE
CWA SATURDAY EVENING. WITH THE DIFFERENCES IN SPEED...ALSO FOLLOWED
THE SIMILAR IDEA FOR THE BACK SIDE OF THE RAIN OVERNIGHT SATURDAY.
STILL APPEARS LIKE A DECENT OPPORTUNITY FOR A QUARTER INCH OF RAIN
OVER MUCH OF THE CWA...ALTHOUGH IT WILL LIKELY FALL IN A 2-3HR
PERIOD. FINALLY...THUNDER POTENTIAL STILL LOOKS TO BE VERY
LIMITED...ESPECIALLY WITH MUCH OF THE RAIN EXPECTED TO BE
POST-FRONTAL. THERE ARE A COUPLE SMALL POCKETS OF 700-500MB LAPSE
RATES APPROACHING 6.5C/KM AHEAD OF THE FRONT AND SIMILAR POCKETS OF
MUCAPE NEAR 250 J/KG. IF A RUMBLE OF THUNDER OCCURS...BELIEVE IT
WOULD BE IN THE WESTERN U.P. IN THE AFTERNOON. BUT...SINCE COVERAGE
SHOULD BE VERY ISOLATED...OPTED TO REMOVE THE SLIGHT CHANCE OF
THUNDER.
WEAK UPPER RIDGE WILL QUICKLY BUILD IN ON SUNDAY AFTERNOON AND
REMAIN INTO MONDAY. THIS WILL LEAD TO ANOTHER DRY PERIOD OF
WEATHER. THERE MAY BE A SOME POST-FRONTAL CLOUDS SUNDAY AFTERNOON
AS A POCKET OF COOLER TEMPERATURES ALOFT MOVE THROUGH. ECMWF/GEM
SEEM TO LIKE THAT IDEA...WHILE GFS KEEPS THINGS CLEAR. SINCE THAT
MOISTURE AND COOLER AIR WILL BE QUICKLY PULLING OUT ON
SUNDAY...WITH FOLLOW THE GENERAL IDEA OF DECREASING CLOUDS ON
SUNDAY. HIGHS WILL BE COOLER ON SUNDAY WITH THAT COLD POCKET OF
AIR...BUT STILL THINK THEY WILL END UP IN THE LOWER-MID 60S IN MOST
LOCATIONS (WHICH IS NORMAL FOR THIS TIME OF YEAR). TEMPERATURES
SHOULD WARM BACK ABOVE NORMAL ON MONDAY WITH HIGHS IN THE UPPER 60S
AND LOWER 70S...AS 850MB TEMPERATURES PUSH BACK INTO THE LOWER
TEENS.
CONUS LOOKS TO COME UNDER ZONAL FLOW FOR TUESDAY AND PART OF
WEDNESDAY...AS THE UPPER JET RUNS WEST-EAST ACROSS THE NORTHERN
ROCKIES. THIS SHOULD KEEP THE MAIN SYNOPTIC FEATURES LOCKED IN
CANADA AND POSSIBLY JUST BRUSHING THE AREA AT TIMES MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL ALSO KEEP THE AREA UNDER ABOVE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 132 PM EDT THU SEP 26 2013
SUMMARY: HIGH PRESSURE OVER QUEBEC WILL GRADUALLY SETTLE SOUTH
THROUGH THE COMING TAF PERIOD...ALLOWING SOUTHERLY WINDS TO
INCREASE. OTHERWISE...WEATHER CONDITIONS ARE EXPECTED TO REMAIN
QUIET THROUGH FRIDAY AFTERNOON.
RESTRICTIONS: GENERALLY VFR THROUGH THE FORECAST PERIOD. ONLY THREAT
OF RESTRICTIONS WILL COME IN THE FORM OF FOG POTENTIAL TONIGHT.
INHERITED IDEA OF SOME LIGHT FOG SAW LOOKS GOOD...WITH TOO MUCH
MIXING TO THE WEST TO ALLOW A REDEVELOPMENT OF FOG. GUT FEELING IS
THAT IF FOG/STRATUS DOES REDEVELOP...IT WILL BE THINNDER AND OCCUR
FURTHER EAST THAN LAST NIGHT...AND THUS IS NOT EXPECTED TO HAVE AS
LARGE OF AN IMPACT AS IT DID THIS MORNING.
WINDS: SOUTHERLY WINDS 5-10KTS WILL DIMINISH TO AROUND 5KTS FOR THE
OVERNIGHT HOURS BEFORE STRENGTHENING TO 10G18KTS FOR THE DAY ON
FRIDAY.
LLWS: GIVEN THE STRENGTHENING GRADIENT THIS EVENING...EXPECT
SOUTHERLY WINDS JUST ABOVE THE SURFACE TO INCREASE TO 25-30KTS...
PRODUCING A PERIOD OF LLWS GIVEN EXPECTED STABLE PROFIILES IN THE LOW
LEVELS. THIS WILL MIX OUT FRIDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EDT THU SEP 26 2013
HIGH PRESSURE OVER WESTERN QUEBEC WILL CONTINUE TO DOMINATE THE
WEATHER FOR TODAY...ALTHOUGH IT WILL BEGIN TO SLIDE SOUTHEAST
TONIGHT. BEFORE THIS OCCURS...THERE IS AN AREA OF FOG (LOCALLY
DENSE) OVER THE WESTERN LAKE EARLY THIS MORNING AND EXPECT THAT TO
DIMINISH THIS MORNING AS DRIER AIR SLIDES IN FROM THE SOUTHEAST.
MEANWHILE...A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE
NORTHERN PLAINS TODAY WILL LINGER A TROUGH EASTERN DAKOTAS TONIGHT
AND THEN SLOWLY MOVE EAST ACROSS MINNESOTA ON FRIDAY. AS THIS
OCCURS...THE PRESSURE GRADIENT AND THUS SOUTHERLY WINDS WILL
INCREASE OVER LAKE SUPERIOR ON FRIDAY. THESE STRONGER WINDS...TO
25KTS...WILL CONTINUE FRIDAY NIGHT AND SATURDAY UNTIL THE TROUGH
MOVES THROUGH LATE SATURDAY AFTERNOON AND EVENING. BEHIND THE
TROUGH...THERE COULD BE A BRIEF PERIOD OF STRONGER WESTERLY WINDS TO
25KTS OVER NORTH CENTRAL LAKE SUPERIOR OVERNIGHT SATURDAY NIGHT INTO
EARLY SUNDAY MORNING. WEAK HIGH PRESSURE WILL BUILD IN TO THE UPPER
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...ARNOTT
SHORT TERM...KC
LONG TERM...SRF
AVIATION...ARNOTT
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1256 PM EDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1249 PM EDT THU SEP 26 2013
CHANGES THIS HOUR: FOG HAS FINALLY GIVEN WAY DOWN TOWARDS KMNM THIS
HOUR...WITH JUST A FEW CIRRUS FILTERING THE SUNSHINE. WILL EXTEND FOG
MENTION OVER NORTHERN GREEN BAY...BUT OTHERWISE LITTLE CHANGES ARE
NEEDED TO THE AFTERNOON FORECAST. TEMPERATURES RUNNING A LITTLE
BEHIND PREVIOUS FORECAST GIVEN THIS LATE CLEAR OUT...BUT DO EXPECT
THEM TO REBOUND NICELY WITH NEARLY FULL SUN THIS AFTERNOON.
UPDATE ISSUED AT 937 AM EDT THU SEP 26 2013
CHANGES THIS HOUR: WILL EXTEND FOG ANOTHER HOUR GIVEN EARLY MORNING
VISIBLE SATELLITE TRENDS WHICH SHOW A /VERY/ SLOW BURNING OFF PROCESS
BEGINNING. OTHERWISE...HAVE LOWERED AFTERNOON DEWPOINTS A TAD BASED
ON DRY AIRMASS CENTERING ITSELF OVERHEAD THIS AFTERNOON...WITH NO
OTHER SIGNIFICANT CHANGES NECESSARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT THU SEP 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A STAGNANT UPR
FLOW OVER THE CONUS WITH UPR RDG OVER THE GREAT LKS SANDWICHED BTWN
SLOW MOVING CLOSED LO OFF THE CANADIAN MARITIMES AND A DEEPENING
TROF OVER THE WRN STATES. SFC HI PRES REMAINS ANCHORED IN QUEBEC...
WITH RDG AXIS EXTENDING SWWD INTO THE UPR LKS. ALTHOUGH ABUNDANT MID
LVL DRY AIR ABOVE SHARP SUBSIDENCE INVRN NEAR H9 SHOWN ON THE 00Z
GRB/APX RAOBS IS BRINGING DRY WX...EFFICIENT NOCTURNAL COOLING HAS
ALLOWED FOG TO FORM OVER MAINLY THE SCENTRAL COUNTIES AND THE
KEWEENAW WHERE LGT E-SE FLOW ARND SFC HI PRES IS UPSLOPING OFF THE
LKS. BUT IN CONTRAST TO LAST NGT...ADVECTION OF VERY DRY NEAR SFC
AIRMASS SHOWN ON THE 00Z APX RAOB /PWAT 0.30 INCH/ IS TENDING TO
LIMIT THE COVERAGE OF THE THICKER FOG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOG TRENDS AND TEMPS AS
WELL AS THE POTENTIAL FOR MORE FOG FORMATION TNGT.
EARLY THIS MRNG/TDAY...MAIN LIMITATION TO WDSPRD DENSE FOG EARLY
THIS MRNG WL BE THE ADVECTION OF THE DRIER LLVL AIR SHOWN ON THE 00Z
APX RAOB. SHORT TERM MODEL FCSTS SHOW THIS DRIER H95-9 AIR BLO THE
SUBSIDENCE INVRN OVERSRREADING UPR MI EARLY THIS MRNG...COUNTERING
TO SOME EXTENT THE IMPACT OF NOCTURNAL COOLING UNDER THE MID LVL DRY
AIR. WL MAINTAIN A MENTION OF AREAS OF FOG UNTIL 13Z OVER THE
SCENTRAL WITH FVRBL UPSLOPE WIND COMPONENT. AWAY FM THIS
AREA...EXPECT NOTHING MORE THAN PATCHY FOG. DOWNSLOPE NATURE OF THE
LLVL FLOW WL LIKELY KEEP MUCH FOG FM DVLPG NEAR LK SUP AND OVER THE
FAR W ARND IWD. ISSUED SPS FOR THE SCENTRAL COUNTIES TO COVER
LOCALLY DENSE FOG IN THIS AREA THRU SUNRISE...BUT AN ADVY WL NOT BE
NECESSARY. ONCE ANY FOG BURNS OFF SOON AFTER SUNRISE...EXPECT
MOSUNNY SKIES. WITH H85 TEMPS FCST UP TO 17C OVER THE W...MAX TEMPS
THERE SHOULD TOP OUT IN THE 70S AWAY FM SOME MODERATION ON MAINLY
THE E SIDE OF THE KEWEENAW IN LLVL SE FLOW. THIS SE FLOW WL TEND TO
LIMIT THE DIURNAL TEMP RISE OVER THE SE COUNTIES.
TNGT...THE UPR RDG AXIS IS FCST TO DRIFT ONLY SLOWLY TO THE E...WITH
SFC HI OVER QUEBEC DRIFTING S INTO NEW ENGLAND. WITH FALLING MSLP IN
THE PLAINS ASSOCIATED WITH SHRTWV LIFTING OUT OF THE WRN TROF...THE
PRES GRADIENT/SLY FLOW IS PROGGED TO SHARPEN OVER MAINLY WRN UPR MI.
THIS INCRSG S WIND IN CONCERT WITH FCST INCRSG PWAT WL RESTRICT THE
DIURNAL TEMP FALL IN THIS AREA...SO TENDED TOWARD THE WARM SIDE OF
GUIDANCE FOR MIN TEMPS OVER THE FAR W FM IWD INTO THE KEWEENAW. A
FLATTER PRES GRADIENT/PWAT FCST AOB 0.50 INCH CLOSER TO THE SFC HI
TO THE E WL SUPPORT LOWER TEMPS OVER THE INTERIOR E HALF...AND FCST
LO TEMPS CLOSER TO THE LO END OF GUIDANCE IN THIS AREA. BUT SOMEWHAT
STRONGER H925 WINDS UP TO 20KTS FCST IN THIS AREA WL LIKELY KEEP THE
LOWS A BIT HIER THAN OBSVD THIS MRNG. WITH THE S WIND OFF LK MI...
EXPECT MORE FOG TO FORM IN THIS AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 406 AM EDT THU SEP 26 2013
FRIDAY WILL BE THE LAST COMPLETELY DRY DAY ACROSS THE CWA AS THE
HIGH PRESSURE RIDGE THAT HAS BEEN INFLUENCING OUR WEATHER SLIDES
SOUTHEAST INTO THE ATLANTIC STATES. AT THE SAME TIME...THE UPPER
TROUGH CURRENTLY OVER THE WESTERN CONUS WILL EJECT OUT OF THE
ROCKIES AND INTO THE CENTRAL AND NORTHERN PLAINS. A SHORTWAVE
EXITING THIS UPPER TROUGH WILL MOVE NORTHEAST THROUGH THE CANADIAN
PRAIRIES WITH AN ASSOCIATED SURFACE LOW THAT LEAVE AN ELONGATED
SURFACE TROUGH STRETCHING SOUTH THROUGH MINNESOTA AND INTO THE
CENTRAL PLAINS. SINCE THAT WILL BE THE MAIN FOCUS OF THE
PRECIPITATION ON FRIDAY AND THE AREA STILL UNDER THE DRY AIR OF THE
HIGH...SHOULD SEE ANOTHER MOSTLY SUNNY DAY ACROSS THE CWA. LATE IN
THE AFTERNOON...COULD SEE SOME MID-HIGH CLOUDS AFFECTING WESTERN
UPPER MICHIGAN. WITH THE SUNSHINE...SHOULD SEE ANOTHER DAY OF ABOVE
NORMAL HIGHS WITH TEMPERATURES IN THE UPPER 60S TO MIDDLE 70S. IT
SHOULD BE A LITTLE BREEZY ON FRIDAY DUE TO THE INCREASING PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING TROUGH...ESPECIALLY
OVER THE WEST WHERE THERE COULD BE GUSTS TO 25-30MPH. EXPECT BREEZY
CONDITIONS TO CONTINUE AT TIMES FRIDAY NIGHT INTO SATURDAY UNTIL
THE FRONT MOVES THROUGH.
THIS DRY AIR WILL REMAIN THROUGH FRIDAY NIGHT AND INTO SATURDAY
MORNING...WITH ONLY A FEW SHOWERS BRUSHING FAR WESTERN LAKE
SUPERIOR DURING THAT TIME. THEN...AS THE UPPER TROUGH EJECTS OUT OF
THE FOUR CORNERS REGION FRIDAY NIGHT...IT PULLS THE ENTIRE UPPER
TROUGH WITH IT AND THROUGH THE UPPER GREAT LAKES REGION THROUGH
SUNDAY. IN ADDITION...A SECONDARY LOW WILL DEVELOP ALONG THE TROUGH
NEAR WESTERN LAKE SUPERIOR AND THE MN ARROWHEAD AS THE RIGHT REAR
OF THE UPPER JET SLIDES NORTHEAST THROUGH THE AREA. THIS WILL ALLOW
A LINE OF SHOWERS ORIENTATED NORTH-SOUTH ALONG AND BEHIND THE
TROUGH TO MOVE EAST-NORTHEAST ACROSS UPPER MICHIGAN. AS HAS BEEN THE
CASE OVER THE LAST SEVERAL NIGHT...THE GFS REMAINS THE FASTEST WITH
THE ARRIVAL OF THE TROUGH/SHOWERS...WHILE THE GEM/ECMWF ARE MORE
CONSISTENT WITH THE SLOWER ARRIVAL. THE NAM ALSO FOLLOWS ALONG WITH
THE FASTER ARRIVAL SHOWN IN THE GFS. SINCE THERE IS AN EVEN SPLIT IN
ARRIVAL TIMES AND ONLY 50-75MI SPREAD...WILL SPLIT THE DIFFERENCE
AT THIS POINT AND HAVE THE WESTERN THIRD/HALF OF UPPER MICHIGAN
SEEING RAIN BY SUNSET AND THEN IT SPREADING ACROSS THE REST OF THE
CWA SATURDAY EVENING. WITH THE DIFFERENCES IN SPEED...ALSO FOLLOWED
THE SIMILAR IDEA FOR THE BACK SIDE OF THE RAIN OVERNIGHT SATURDAY.
STILL APPEARS LIKE A DECENT OPPORTUNITY FOR A QUARTER INCH OF RAIN
OVER MUCH OF THE CWA...ALTHOUGH IT WILL LIKELY FALL IN A 2-3HR
PERIOD. FINALLY...THUNDER POTENTIAL STILL LOOKS TO BE VERY
LIMITED...ESPECIALLY WITH MUCH OF THE RAIN EXPECTED TO BE
POST-FRONTAL. THERE ARE A COUPLE SMALL POCKETS OF 700-500MB LAPSE
RATES APPROACHING 6.5C/KM AHEAD OF THE FRONT AND SIMILAR POCKETS OF
MUCAPE NEAR 250 J/KG. IF A RUMBLE OF THUNDER OCCURS...BELIEVE IT
WOULD BE IN THE WESTERN U.P. IN THE AFTERNOON. BUT...SINCE COVERAGE
SHOULD BE VERY ISOLATED...OPTED TO REMOVE THE SLIGHT CHANCE OF
THUNDER.
WEAK UPPER RIDGE WILL QUICKLY BUILD IN ON SUNDAY AFTERNOON AND
REMAIN INTO MONDAY. THIS WILL LEAD TO ANOTHER DRY PERIOD OF
WEATHER. THERE MAY BE A SOME POST-FRONTAL CLOUDS SUNDAY AFTERNOON
AS A POCKET OF COOLER TEMPERATURES ALOFT MOVE THROUGH. ECMWF/GEM
SEEM TO LIKE THAT IDEA...WHILE GFS KEEPS THINGS CLEAR. SINCE THAT
MOISTURE AND COOLER AIR WILL BE QUICKLY PULLING OUT ON
SUNDAY...WITH FOLLOW THE GENERAL IDEA OF DECREASING CLOUDS ON
SUNDAY. HIGHS WILL BE COOLER ON SUNDAY WITH THAT COLD POCKET OF
AIR...BUT STILL THINK THEY WILL END UP IN THE LOWER-MID 60S IN MOST
LOCATIONS (WHICH IS NORMAL FOR THIS TIME OF YEAR). TEMPERATURES
SHOULD WARM BACK ABOVE NORMAL ON MONDAY WITH HIGHS IN THE UPPER 60S
AND LOWER 70S...AS 850MB TEMPERATURES PUSH BACK INTO THE LOWER
TEENS.
CONUS LOOKS TO COME UNDER ZONAL FLOW FOR TUESDAY AND PART OF
WEDNESDAY...AS THE UPPER JET RUNS WEST-EAST ACROSS THE NORTHERN
ROCKIES. THIS SHOULD KEEP THE MAIN SYNOPTIC FEATURES LOCKED IN
CANADA AND POSSIBLY JUST BRUSHING THE AREA AT TIMES MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL ALSO KEEP THE AREA UNDER ABOVE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 725 AM EDT THU SEP 26 2013
LINGERING FOG/IFR TO VLIFR CONDITIONS WL GIVE WAY TO VFR CONDITIONS
BY MID MRNG WITH THE ONSET OF DAYTIME HEATING THAT MIXES OUT THE
FOG. THEN VFR WX WL PREVAIL AT ALL 3 TAF SITES THRU AT LEAST 06Z
TNGT. A STRONGER S WIND ABOVE RADIATION INVRN TNGT THAT WL CAUSE
LLWS AT IWD SHOULD PREVENT MORE FOG FORMATION AT IWD AND CMX. BUT AT
SAW...UPSLOPE NATURE OF THE S WIND OFF LK MI AND SOMEWHAT WEAKER
FLOW THAT WL ALLOW MORE EFFICIENT RADIATIONAL COOLING WL BE
SUFFICIENT FOR A BETTER CHC OF RADIATION FOG AT THAT LOCATION. IF
THE WINDS ARE LIGHTER THAN EXPECTED AT SAW...IFR CONDITIONS MIGHT BE
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EDT THU SEP 26 2013
HIGH PRESSURE OVER WESTERN QUEBEC WILL CONTINUE TO DOMINATE THE
WEATHER FOR TODAY...ALTHOUGH IT WILL BEGIN TO SLIDE SOUTHEAST
TONIGHT. BEFORE THIS OCCURS...THERE IS AN AREA OF FOG (LOCALLY
DENSE) OVER THE WESTERN LAKE EARLY THIS MORNING AND EXPECT THAT TO
DIMINISH THIS MORNING AS DRIER AIR SLIDES IN FROM THE SOUTHEAST.
MEANWHILE...A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE
NORTHERN PLAINS TODAY WILL LINGER A TROUGH EASTERN DAKOTAS TONIGHT
AND THEN SLOWLY MOVE EAST ACROSS MINNESOTA ON FRIDAY. AS THIS
OCCURS...THE PRESSURE GRADIENT AND THUS SOUTHERLY WINDS WILL
INCREASE OVER LAKE SUPERIOR ON FRIDAY. THESE STRONGER WINDS...TO
25KTS...WILL CONTINUE FRIDAY NIGHT AND SATURDAY UNTIL THE TROUGH
MOVES THROUGH LATE SATURDAY AFTERNOON AND EVENING. BEHIND THE
TROUGH...THERE COULD BE A BRIEF PERIOD OF STRONGER WESTERLY WINDS TO
25KTS OVER NORTH CENTRAL LAKE SUPERIOR OVERNIGHT SATURDAY NIGHT INTO
EARLY SUNDAY MORNING. WEAK HIGH PRESSURE WILL BUILD IN TO THE UPPER
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...ARNOTT
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
944 AM EDT THU SEP 26 2013
.UPDATE...
ISSUED AT 937 AM EDT THU SEP 26 2013
CHANGES THIS HOUR: WILL EXTEND FOG ANOTHER HOUR GIVEN EARLY MORNING
VISIBLE SATELLITE TRENDS WHICH SHOW A /VERY/ SLOW BURNING OFF PROCESS
BEGINNING. OTHERWISE...HAVE LOWERED AFTERNOON DEWPOINTS A TAD BASED
ON DRY AIRMASS CENTERING ITSELF OVERHEAD THIS AFTERNOON...WITH NO
OTHER SIGNIFICANT CHANGES NECESSARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT THU SEP 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A STAGNANT UPR
FLOW OVER THE CONUS WITH UPR RDG OVER THE GREAT LKS SANDWICHED BTWN
SLOW MOVING CLOSED LO OFF THE CANADIAN MARITIMES AND A DEEPENING
TROF OVER THE WRN STATES. SFC HI PRES REMAINS ANCHORED IN QUEBEC...
WITH RDG AXIS EXTENDING SWWD INTO THE UPR LKS. ALTHOUGH ABUNDANT MID
LVL DRY AIR ABOVE SHARP SUBSIDENCE INVRN NEAR H9 SHOWN ON THE 00Z
GRB/APX RAOBS IS BRINGING DRY WX...EFFICIENT NOCTURNAL COOLING HAS
ALLOWED FOG TO FORM OVER MAINLY THE SCENTRAL COUNTIES AND THE
KEWEENAW WHERE LGT E-SE FLOW ARND SFC HI PRES IS UPSLOPING OFF THE
LKS. BUT IN CONTRAST TO LAST NGT...ADVECTION OF VERY DRY NEAR SFC
AIRMASS SHOWN ON THE 00Z APX RAOB /PWAT 0.30 INCH/ IS TENDING TO
LIMIT THE COVERAGE OF THE THICKER FOG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOG TRENDS AND TEMPS AS
WELL AS THE POTENTIAL FOR MORE FOG FORMATION TNGT.
EARLY THIS MRNG/TDAY...MAIN LIMITATION TO WDSPRD DENSE FOG EARLY
THIS MRNG WL BE THE ADVECTION OF THE DRIER LLVL AIR SHOWN ON THE 00Z
APX RAOB. SHORT TERM MODEL FCSTS SHOW THIS DRIER H95-9 AIR BLO THE
SUBSIDENCE INVRN OVERSRREADING UPR MI EARLY THIS MRNG...COUNTERING
TO SOME EXTENT THE IMPACT OF NOCTURNAL COOLING UNDER THE MID LVL DRY
AIR. WL MAINTAIN A MENTION OF AREAS OF FOG UNTIL 13Z OVER THE
SCENTRAL WITH FVRBL UPSLOPE WIND COMPONENT. AWAY FM THIS
AREA...EXPECT NOTHING MORE THAN PATCHY FOG. DOWNSLOPE NATURE OF THE
LLVL FLOW WL LIKELY KEEP MUCH FOG FM DVLPG NEAR LK SUP AND OVER THE
FAR W ARND IWD. ISSUED SPS FOR THE SCENTRAL COUNTIES TO COVER
LOCALLY DENSE FOG IN THIS AREA THRU SUNRISE...BUT AN ADVY WL NOT BE
NECESSARY. ONCE ANY FOG BURNS OFF SOON AFTER SUNRISE...EXPECT
MOSUNNY SKIES. WITH H85 TEMPS FCST UP TO 17C OVER THE W...MAX TEMPS
THERE SHOULD TOP OUT IN THE 70S AWAY FM SOME MODERATION ON MAINLY
THE E SIDE OF THE KEWEENAW IN LLVL SE FLOW. THIS SE FLOW WL TEND TO
LIMIT THE DIURNAL TEMP RISE OVER THE SE COUNTIES.
TNGT...THE UPR RDG AXIS IS FCST TO DRIFT ONLY SLOWLY TO THE E...WITH
SFC HI OVER QUEBEC DRIFTING S INTO NEW ENGLAND. WITH FALLING MSLP IN
THE PLAINS ASSOCIATED WITH SHRTWV LIFTING OUT OF THE WRN TROF...THE
PRES GRADIENT/SLY FLOW IS PROGGED TO SHARPEN OVER MAINLY WRN UPR MI.
THIS INCRSG S WIND IN CONCERT WITH FCST INCRSG PWAT WL RESTRICT THE
DIURNAL TEMP FALL IN THIS AREA...SO TENDED TOWARD THE WARM SIDE OF
GUIDANCE FOR MIN TEMPS OVER THE FAR W FM IWD INTO THE KEWEENAW. A
FLATTER PRES GRADIENT/PWAT FCST AOB 0.50 INCH CLOSER TO THE SFC HI
TO THE E WL SUPPORT LOWER TEMPS OVER THE INTERIOR E HALF...AND FCST
LO TEMPS CLOSER TO THE LO END OF GUIDANCE IN THIS AREA. BUT SOMEWHAT
STRONGER H925 WINDS UP TO 20KTS FCST IN THIS AREA WL LIKELY KEEP THE
LOWS A BIT HIER THAN OBSVD THIS MRNG. WITH THE S WIND OFF LK MI...
EXPECT MORE FOG TO FORM IN THIS AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 406 AM EDT THU SEP 26 2013
FRIDAY WILL BE THE LAST COMPLETELY DRY DAY ACROSS THE CWA AS THE
HIGH PRESSURE RIDGE THAT HAS BEEN INFLUENCING OUR WEATHER SLIDES
SOUTHEAST INTO THE ATLANTIC STATES. AT THE SAME TIME...THE UPPER
TROUGH CURRENTLY OVER THE WESTERN CONUS WILL EJECT OUT OF THE
ROCKIES AND INTO THE CENTRAL AND NORTHERN PLAINS. A SHORTWAVE
EXITING THIS UPPER TROUGH WILL MOVE NORTHEAST THROUGH THE CANADIAN
PRAIRIES WITH AN ASSOCIATED SURFACE LOW THAT LEAVE AN ELONGATED
SURFACE TROUGH STRETCHING SOUTH THROUGH MINNESOTA AND INTO THE
CENTRAL PLAINS. SINCE THAT WILL BE THE MAIN FOCUS OF THE
PRECIPITATION ON FRIDAY AND THE AREA STILL UNDER THE DRY AIR OF THE
HIGH...SHOULD SEE ANOTHER MOSTLY SUNNY DAY ACROSS THE CWA. LATE IN
THE AFTERNOON...COULD SEE SOME MID-HIGH CLOUDS AFFECTING WESTERN
UPPER MICHIGAN. WITH THE SUNSHINE...SHOULD SEE ANOTHER DAY OF ABOVE
NORMAL HIGHS WITH TEMPERATURES IN THE UPPER 60S TO MIDDLE 70S. IT
SHOULD BE A LITTLE BREEZY ON FRIDAY DUE TO THE INCREASING PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING TROUGH...ESPECIALLY
OVER THE WEST WHERE THERE COULD BE GUSTS TO 25-30MPH. EXPECT BREEZY
CONDITIONS TO CONTINUE AT TIMES FRIDAY NIGHT INTO SATURDAY UNTIL
THE FRONT MOVES THROUGH.
THIS DRY AIR WILL REMAIN THROUGH FRIDAY NIGHT AND INTO SATURDAY
MORNING...WITH ONLY A FEW SHOWERS BRUSHING FAR WESTERN LAKE
SUPERIOR DURING THAT TIME. THEN...AS THE UPPER TROUGH EJECTS OUT OF
THE FOUR CORNERS REGION FRIDAY NIGHT...IT PULLS THE ENTIRE UPPER
TROUGH WITH IT AND THROUGH THE UPPER GREAT LAKES REGION THROUGH
SUNDAY. IN ADDITION...A SECONDARY LOW WILL DEVELOP ALONG THE TROUGH
NEAR WESTERN LAKE SUPERIOR AND THE MN ARROWHEAD AS THE RIGHT REAR
OF THE UPPER JET SLIDES NORTHEAST THROUGH THE AREA. THIS WILL ALLOW
A LINE OF SHOWERS ORIENTATED NORTH-SOUTH ALONG AND BEHIND THE
TROUGH TO MOVE EAST-NORTHEAST ACROSS UPPER MICHIGAN. AS HAS BEEN THE
CASE OVER THE LAST SEVERAL NIGHT...THE GFS REMAINS THE FASTEST WITH
THE ARRIVAL OF THE TROUGH/SHOWERS...WHILE THE GEM/ECMWF ARE MORE
CONSISTENT WITH THE SLOWER ARRIVAL. THE NAM ALSO FOLLOWS ALONG WITH
THE FASTER ARRIVAL SHOWN IN THE GFS. SINCE THERE IS AN EVEN SPLIT IN
ARRIVAL TIMES AND ONLY 50-75MI SPREAD...WILL SPLIT THE DIFFERENCE
AT THIS POINT AND HAVE THE WESTERN THIRD/HALF OF UPPER MICHIGAN
SEEING RAIN BY SUNSET AND THEN IT SPREADING ACROSS THE REST OF THE
CWA SATURDAY EVENING. WITH THE DIFFERENCES IN SPEED...ALSO FOLLOWED
THE SIMILAR IDEA FOR THE BACK SIDE OF THE RAIN OVERNIGHT SATURDAY.
STILL APPEARS LIKE A DECENT OPPORTUNITY FOR A QUARTER INCH OF RAIN
OVER MUCH OF THE CWA...ALTHOUGH IT WILL LIKELY FALL IN A 2-3HR
PERIOD. FINALLY...THUNDER POTENTIAL STILL LOOKS TO BE VERY
LIMITED...ESPECIALLY WITH MUCH OF THE RAIN EXPECTED TO BE
POST-FRONTAL. THERE ARE A COUPLE SMALL POCKETS OF 700-500MB LAPSE
RATES APPROACHING 6.5C/KM AHEAD OF THE FRONT AND SIMILAR POCKETS OF
MUCAPE NEAR 250 J/KG. IF A RUMBLE OF THUNDER OCCURS...BELIEVE IT
WOULD BE IN THE WESTERN U.P. IN THE AFTERNOON. BUT...SINCE COVERAGE
SHOULD BE VERY ISOLATED...OPTED TO REMOVE THE SLIGHT CHANCE OF
THUNDER.
WEAK UPPER RIDGE WILL QUICKLY BUILD IN ON SUNDAY AFTERNOON AND
REMAIN INTO MONDAY. THIS WILL LEAD TO ANOTHER DRY PERIOD OF
WEATHER. THERE MAY BE A SOME POST-FRONTAL CLOUDS SUNDAY AFTERNOON
AS A POCKET OF COOLER TEMPERATURES ALOFT MOVE THROUGH. ECMWF/GEM
SEEM TO LIKE THAT IDEA...WHILE GFS KEEPS THINGS CLEAR. SINCE THAT
MOISTURE AND COOLER AIR WILL BE QUICKLY PULLING OUT ON
SUNDAY...WITH FOLLOW THE GENERAL IDEA OF DECREASING CLOUDS ON
SUNDAY. HIGHS WILL BE COOLER ON SUNDAY WITH THAT COLD POCKET OF
AIR...BUT STILL THINK THEY WILL END UP IN THE LOWER-MID 60S IN MOST
LOCATIONS (WHICH IS NORMAL FOR THIS TIME OF YEAR). TEMPERATURES
SHOULD WARM BACK ABOVE NORMAL ON MONDAY WITH HIGHS IN THE UPPER 60S
AND LOWER 70S...AS 850MB TEMPERATURES PUSH BACK INTO THE LOWER
TEENS.
CONUS LOOKS TO COME UNDER ZONAL FLOW FOR TUESDAY AND PART OF
WEDNESDAY...AS THE UPPER JET RUNS WEST-EAST ACROSS THE NORTHERN
ROCKIES. THIS SHOULD KEEP THE MAIN SYNOPTIC FEATURES LOCKED IN
CANADA AND POSSIBLY JUST BRUSHING THE AREA AT TIMES MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL ALSO KEEP THE AREA UNDER ABOVE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 725 AM EDT THU SEP 26 2013
LINGERING FOG/IFR TO VLIFR CONDITIONS WL GIVE WAY TO VFR CONDITIONS
BY MID MRNG WITH THE ONSET OF DAYTIME HEATING THAT MIXES OUT THE
FOG. THEN VFR WX WL PREVAIL AT ALL 3 TAF SITES THRU AT LEAST 06Z
TNGT. A STRONGER S WIND ABOVE RADIATION INVRN TNGT THAT WL CAUSE
LLWS AT IWD SHOULD PREVENT MORE FOG FORMATION AT IWD AND CMX. BUT AT
SAW...UPSLOPE NATURE OF THE S WIND OFF LK MI AND SOMEWHAT WEAKER
FLOW THAT WL ALLOW MORE EFFICIENT RADIATIONAL COOLING WL BE
SUFFICIENT FOR A BETTER CHC OF RADIATION FOG AT THAT LOCATION. IF
THE WINDS ARE LIGHTER THAN EXPECTED AT SAW...IFR CONDITIONS MIGHT BE
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EDT THU SEP 26 2013
HIGH PRESSURE OVER WESTERN QUEBEC WILL CONTINUE TO DOMINATE THE
WEATHER FOR TODAY...ALTHOUGH IT WILL BEGIN TO SLIDE SOUTHEAST
TONIGHT. BEFORE THIS OCCURS...THERE IS AN AREA OF FOG (LOCALLY
DENSE) OVER THE WESTERN LAKE EARLY THIS MORNING AND EXPECT THAT TO
DIMINISH THIS MORNING AS DRIER AIR SLIDES IN FROM THE SOUTHEAST.
MEANWHILE...A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE
NORTHERN PLAINS TODAY WILL LINGER A TROUGH EASTERN DAKOTAS TONIGHT
AND THEN SLOWLY MOVE EAST ACROSS MINNESOTA ON FRIDAY. AS THIS
OCCURS...THE PRESSURE GRADIENT AND THUS SOUTHERLY WINDS WILL
INCREASE OVER LAKE SUPERIOR ON FRIDAY. THESE STRONGER WINDS...TO
25KTS...WILL CONTINUE FRIDAY NIGHT AND SATURDAY UNTIL THE TROUGH
MOVES THROUGH LATE SATURDAY AFTERNOON AND EVENING. BEHIND THE
TROUGH...THERE COULD BE A BRIEF PERIOD OF STRONGER WESTERLY WINDS TO
25KTS OVER NORTH CENTRAL LAKE SUPERIOR OVERNIGHT SATURDAY NIGHT INTO
EARLY SUNDAY MORNING. WEAK HIGH PRESSURE WILL BUILD IN TO THE UPPER
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...ARNOTT
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 AM EDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT THU SEP 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A STAGNANT UPR
FLOW OVER THE CONUS WITH UPR RDG OVER THE GREAT LKS SANDWICHED BTWN
SLOW MOVING CLOSED LO OFF THE CANADIAN MARITIMES AND A DEEPENING
TROF OVER THE WRN STATES. SFC HI PRES REMAINS ANCHORED IN QUEBEC...
WITH RDG AXIS EXTENDING SWWD INTO THE UPR LKS. ALTHOUGH ABUNDANT MID
LVL DRY AIR ABOVE SHARP SUBSIDENCE INVRN NEAR H9 SHOWN ON THE 00Z
GRB/APX RAOBS IS BRINGING DRY WX...EFFICIENT NOCTURNAL COOLING HAS
ALLOWED FOG TO FORM OVER MAINLY THE SCENTRAL COUNTIES AND THE
KEWEENAW WHERE LGT E-SE FLOW ARND SFC HI PRES IS UPSLOPING OFF THE
LKS. BUT IN CONTRAST TO LAST NGT...ADVECTION OF VERY DRY NEAR SFC
AIRMASS SHOWN ON THE 00Z APX RAOB /PWAT 0.30 INCH/ IS TENDING TO
LIMIT THE COVERAGE OF THE THICKER FOG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOG TRENDS AND TEMPS AS
WELL AS THE POTENTIAL FOR MORE FOG FORMATION TNGT.
EARLY THIS MRNG/TDAY...MAIN LIMITATION TO WDSPRD DENSE FOG EARLY
THIS MRNG WL BE THE ADVECTION OF THE DRIER LLVL AIR SHOWN ON THE 00Z
APX RAOB. SHORT TERM MODEL FCSTS SHOW THIS DRIER H95-9 AIR BLO THE
SUBSIDENCE INVRN OVERSRREADING UPR MI EARLY THIS MRNG...COUNTERING
TO SOME EXTENT THE IMPACT OF NOCTURNAL COOLING UNDER THE MID LVL DRY
AIR. WL MAINTAIN A MENTION OF AREAS OF FOG UNTIL 13Z OVER THE
SCENTRAL WITH FVRBL UPSLOPE WIND COMPONENT. AWAY FM THIS
AREA...EXPECT NOTHING MORE THAN PATCHY FOG. DOWNSLOPE NATURE OF THE
LLVL FLOW WL LIKELY KEEP MUCH FOG FM DVLPG NEAR LK SUP AND OVER THE
FAR W ARND IWD. ISSUED SPS FOR THE SCENTRAL COUNTIES TO COVER
LOCALLY DENSE FOG IN THIS AREA THRU SUNRISE...BUT AN ADVY WL NOT BE
NECESSARY. ONCE ANY FOG BURNS OFF SOON AFTER SUNRISE...EXPECT
MOSUNNY SKIES. WITH H85 TEMPS FCST UP TO 17C OVER THE W...MAX TEMPS
THERE SHOULD TOP OUT IN THE 70S AWAY FM SOME MODERATION ON MAINLY
THE E SIDE OF THE KEWEENAW IN LLVL SE FLOW. THIS SE FLOW WL TEND TO
LIMIT THE DIURNAL TEMP RISE OVER THE SE COUNTIES.
TNGT...THE UPR RDG AXIS IS FCST TO DRIFT ONLY SLOWLY TO THE E...WITH
SFC HI OVER QUEBEC DRIFTING S INTO NEW ENGLAND. WITH FALLING MSLP IN
THE PLAINS ASSOCIATED WITH SHRTWV LIFTING OUT OF THE WRN TROF...THE
PRES GRADIENT/SLY FLOW IS PROGGED TO SHARPEN OVER MAINLY WRN UPR MI.
THIS INCRSG S WIND IN CONCERT WITH FCST INCRSG PWAT WL RESTRICT THE
DIURNAL TEMP FALL IN THIS AREA...SO TENDED TOWARD THE WARM SIDE OF
GUIDANCE FOR MIN TEMPS OVER THE FAR W FM IWD INTO THE KEWEENAW. A
FLATTER PRES GRADIENT/PWAT FCST AOB 0.50 INCH CLOSER TO THE SFC HI
TO THE E WL SUPPORT LOWER TEMPS OVER THE INTERIOR E HALF...AND FCST
LO TEMPS CLOSER TO THE LO END OF GUIDANCE IN THIS AREA. BUT SOMEWHAT
STRONGER H925 WINDS UP TO 20KTS FCST IN THIS AREA WL LIKELY KEEP THE
LOWS A BIT HIER THAN OBSVD THIS MRNG. WITH THE S WIND OFF LK MI...
EXPECT MORE FOG TO FORM IN THIS AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 406 AM EDT THU SEP 26 2013
FRIDAY WILL BE THE LAST COMPLETELY DRY DAY ACROSS THE CWA AS THE
HIGH PRESSURE RIDGE THAT HAS BEEN INFLUENCING OUR WEATHER SLIDES
SOUTHEAST INTO THE ATLANTIC STATES. AT THE SAME TIME...THE UPPER
TROUGH CURRENTLY OVER THE WESTERN CONUS WILL EJECT OUT OF THE
ROCKIES AND INTO THE CENTRAL AND NORTHERN PLAINS. A SHORTWAVE
EXITING THIS UPPER TROUGH WILL MOVE NORTHEAST THROUGH THE CANADIAN
PRAIRIES WITH AN ASSOCIATED SURFACE LOW THAT LEAVE AN ELONGATED
SURFACE TROUGH STRETCHING SOUTH THROUGH MINNESOTA AND INTO THE
CENTRAL PLAINS. SINCE THAT WILL BE THE MAIN FOCUS OF THE
PRECIPITATION ON FRIDAY AND THE AREA STILL UNDER THE DRY AIR OF THE
HIGH...SHOULD SEE ANOTHER MOSTLY SUNNY DAY ACROSS THE CWA. LATE IN
THE AFTERNOON...COULD SEE SOME MID-HIGH CLOUDS AFFECTING WESTERN
UPPER MICHIGAN. WITH THE SUNSHINE...SHOULD SEE ANOTHER DAY OF ABOVE
NORMAL HIGHS WITH TEMPERATURES IN THE UPPER 60S TO MIDDLE 70S. IT
SHOULD BE A LITTLE BREEZY ON FRIDAY DUE TO THE INCREASING PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING TROUGH...ESPECIALLY
OVER THE WEST WHERE THERE COULD BE GUSTS TO 25-30MPH. EXPECT BREEZY
CONDITIONS TO CONTINUE AT TIMES FRIDAY NIGHT INTO SATURDAY UNTIL
THE FRONT MOVES THROUGH.
THIS DRY AIR WILL REMAIN THROUGH FRIDAY NIGHT AND INTO SATURDAY
MORNING...WITH ONLY A FEW SHOWERS BRUSHING FAR WESTERN LAKE
SUPERIOR DURING THAT TIME. THEN...AS THE UPPER TROUGH EJECTS OUT OF
THE FOUR CORNERS REGION FRIDAY NIGHT...IT PULLS THE ENTIRE UPPER
TROUGH WITH IT AND THROUGH THE UPPER GREAT LAKES REGION THROUGH
SUNDAY. IN ADDITION...A SECONDARY LOW WILL DEVELOP ALONG THE TROUGH
NEAR WESTERN LAKE SUPERIOR AND THE MN ARROWHEAD AS THE RIGHT REAR
OF THE UPPER JET SLIDES NORTHEAST THROUGH THE AREA. THIS WILL ALLOW
A LINE OF SHOWERS ORIENTATED NORTH-SOUTH ALONG AND BEHIND THE
TROUGH TO MOVE EAST-NORTHEAST ACROSS UPPER MICHIGAN. AS HAS BEEN THE
CASE OVER THE LAST SEVERAL NIGHT...THE GFS REMAINS THE FASTEST WITH
THE ARRIVAL OF THE TROUGH/SHOWERS...WHILE THE GEM/ECMWF ARE MORE
CONSISTENT WITH THE SLOWER ARRIVAL. THE NAM ALSO FOLLOWS ALONG WITH
THE FASTER ARRIVAL SHOWN IN THE GFS. SINCE THERE IS AN EVEN SPLIT IN
ARRIVAL TIMES AND ONLY 50-75MI SPREAD...WILL SPLIT THE DIFFERENCE
AT THIS POINT AND HAVE THE WESTERN THIRD/HALF OF UPPER MICHIGAN
SEEING RAIN BY SUNSET AND THEN IT SPREADING ACROSS THE REST OF THE
CWA SATURDAY EVENING. WITH THE DIFFERENCES IN SPEED...ALSO FOLLOWED
THE SIMILAR IDEA FOR THE BACK SIDE OF THE RAIN OVERNIGHT SATURDAY.
STILL APPEARS LIKE A DECENT OPPORTUNITY FOR A QUARTER INCH OF RAIN
OVER MUCH OF THE CWA...ALTHOUGH IT WILL LIKELY FALL IN A 2-3HR
PERIOD. FINALLY...THUNDER POTENTIAL STILL LOOKS TO BE VERY
LIMITED...ESPECIALLY WITH MUCH OF THE RAIN EXPECTED TO BE
POST-FRONTAL. THERE ARE A COUPLE SMALL POCKETS OF 700-500MB LAPSE
RATES APPROACHING 6.5C/KM AHEAD OF THE FRONT AND SIMILAR POCKETS OF
MUCAPE NEAR 250 J/KG. IF A RUMBLE OF THUNDER OCCURS...BELIEVE IT
WOULD BE IN THE WESTERN U.P. IN THE AFTERNOON. BUT...SINCE COVERAGE
SHOULD BE VERY ISOLATED...OPTED TO REMOVE THE SLIGHT CHANCE OF
THUNDER.
WEAK UPPER RIDGE WILL QUICKLY BUILD IN ON SUNDAY AFTERNOON AND
REMAIN INTO MONDAY. THIS WILL LEAD TO ANOTHER DRY PERIOD OF
WEATHER. THERE MAY BE A SOME POST-FRONTAL CLOUDS SUNDAY AFTERNOON
AS A POCKET OF COOLER TEMPERATURES ALOFT MOVE THROUGH. ECMWF/GEM
SEEM TO LIKE THAT IDEA...WHILE GFS KEEPS THINGS CLEAR. SINCE THAT
MOISTURE AND COOLER AIR WILL BE QUICKLY PULLING OUT ON
SUNDAY...WITH FOLLOW THE GENERAL IDEA OF DECREASING CLOUDS ON
SUNDAY. HIGHS WILL BE COOLER ON SUNDAY WITH THAT COLD POCKET OF
AIR...BUT STILL THINK THEY WILL END UP IN THE LOWER-MID 60S IN MOST
LOCATIONS (WHICH IS NORMAL FOR THIS TIME OF YEAR). TEMPERATURES
SHOULD WARM BACK ABOVE NORMAL ON MONDAY WITH HIGHS IN THE UPPER 60S
AND LOWER 70S...AS 850MB TEMPERATURES PUSH BACK INTO THE LOWER
TEENS.
CONUS LOOKS TO COME UNDER ZONAL FLOW FOR TUESDAY AND PART OF
WEDNESDAY...AS THE UPPER JET RUNS WEST-EAST ACROSS THE NORTHERN
ROCKIES. THIS SHOULD KEEP THE MAIN SYNOPTIC FEATURES LOCKED IN
CANADA AND POSSIBLY JUST BRUSHING THE AREA AT TIMES MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL ALSO KEEP THE AREA UNDER ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 725 AM EDT THU SEP 26 2013
LINGERING FOG/IFR TO VLIFR CONDITIONS WL GIVE WAY TO VFR CONDITIONS
BY MID MRNG WITH THE ONSET OF DAYTIME HEATING THAT MIXES OUT THE
FOG. THEN VFR WX WL PREVAIL AT ALL 3 TAF SITES THRU AT LEAST 06Z
TNGT. A STRONGER S WIND ABOVE RADIATION INVRN TNGT THAT WL CAUSE
LLWS AT IWD SHOULD PREVENT MORE FOG FORMATION AT IWD AND CMX. BUT AT
SAW...UPSLOPE NATURE OF THE S WIND OFF LK MI AND SOMEWHAT WEAKER
FLOW THAT WL ALLOW MORE EFFICIENT RADIATIONAL COOLING WL BE
SUFFICIENT FOR A BETTER CHC OF RADIATION FOG AT THAT LOCATION. IF
THE WINDS ARE LIGHTER THAN EXPECTED AT SAW...IFR CONDITIONS MIGHT BE
PSBL FOR AT LEAST A PORTION OF THE TIME THERE AFT 06Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EDT THU SEP 26 2013
HIGH PRESSURE OVER WESTERN QUEBEC WILL CONTINUE TO DOMINATE THE
WEATHER FOR TODAY...ALTHOUGH IT WILL BEGIN TO SLIDE SOUTHEAST
TONIGHT. BEFORE THIS OCCURS...THERE IS AN AREA OF FOG (LOCALLY
DENSE) OVER THE WESTERN LAKE EARLY THIS MORNING AND EXPECT THAT TO
DIMINISH THIS MORNING AS DRIER AIR SLIDES IN FROM THE SOUTHEAST.
MEANWHILE...A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE
NORTHERN PLAINS TODAY WILL LINGER A TROUGH EASTERN DAKOTAS TONIGHT
AND THEN SLOWLY MOVE EAST ACROSS MINNESOTA ON FRIDAY. AS THIS
OCCURS...THE PRESSURE GRADIENT AND THUS SOUTHERLY WINDS WILL
INCREASE OVER LAKE SUPERIOR ON FRIDAY. THESE STRONGER WINDS...TO
25KTS...WILL CONTINUE FRIDAY NIGHT AND SATURDAY UNTIL THE TROUGH
MOVES THROUGH LATE SATURDAY AFTERNOON AND EVENING. BEHIND THE
TROUGH...THERE COULD BE A BRIEF PERIOD OF STRONGER WESTERLY WINDS TO
25KTS OVER NORTH CENTRAL LAKE SUPERIOR OVERNIGHT SATURDAY NIGHT INTO
EARLY SUNDAY MORNING. WEAK HIGH PRESSURE WILL BUILD IN TO THE UPPER
GREAT LAKES ON SUNDAY NIGHT AND MONDAY AND LOWER WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 AM EDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT THU SEP 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A STAGNANT UPR
FLOW OVER THE CONUS WITH UPR RDG OVER THE GREAT LKS SANDWICHED BTWN
SLOW MOVING CLOSED LO OFF THE CANADIAN MARITIMES AND A DEEPENING
TROF OVER THE WRN STATES. SFC HI PRES REMAINS ANCHORED IN QUEBEC...
WITH RDG AXIS EXTENDING SWWD INTO THE UPR LKS. ALTHOUGH ABUNDANT MID
LVL DRY AIR ABOVE SHARP SUBSIDENCE INVRN NEAR H9 SHOWN ON THE 00Z
GRB/APX RAOBS IS BRINGING DRY WX...EFFICIENT NOCTURNAL COOLING HAS
ALLOWED FOG TO FORM OVER MAINLY THE SCENTRAL COUNTIES AND THE
KEWEENAW WHERE LGT E-SE FLOW ARND SFC HI PRES IS UPSLOPING OFF THE
LKS. BUT IN CONTRAST TO LAST NGT...ADVECTION OF VERY DRY NEAR SFC
AIRMASS SHOWN ON THE 00Z APX RAOB /PWAT 0.30 INCH/ IS TENDING TO
LIMIT THE COVERAGE OF THE THICKER FOG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOG TRENDS AND TEMPS AS
WELL AS THE POTENTIAL FOR MORE FOG FORMATION TNGT.
EARLY THIS MRNG/TDAY...MAIN LIMITATION TO WDSPRD DENSE FOG EARLY
THIS MRNG WL BE THE ADVECTION OF THE DRIER LLVL AIR SHOWN ON THE 00Z
APX RAOB. SHORT TERM MODEL FCSTS SHOW THIS DRIER H95-9 AIR BLO THE
SUBSIDENCE INVRN OVERSRREADING UPR MI EARLY THIS MRNG...COUNTERING
TO SOME EXTENT THE IMPACT OF NOCTURNAL COOLING UNDER THE MID LVL DRY
AIR. WL MAINTAIN A MENTION OF AREAS OF FOG UNTIL 13Z OVER THE
SCENTRAL WITH FVRBL UPSLOPE WIND COMPONENT. AWAY FM THIS
AREA...EXPECT NOTHING MORE THAN PATCHY FOG. DOWNSLOPE NATURE OF THE
LLVL FLOW WL LIKELY KEEP MUCH FOG FM DVLPG NEAR LK SUP AND OVER THE
FAR W ARND IWD. ISSUED SPS FOR THE SCENTRAL COUNTIES TO COVER
LOCALLY DENSE FOG IN THIS AREA THRU SUNRISE...BUT AN ADVY WL NOT BE
NECESSARY. ONCE ANY FOG BURNS OFF SOON AFTER SUNRISE...EXPECT
MOSUNNY SKIES. WITH H85 TEMPS FCST UP TO 17C OVER THE W...MAX TEMPS
THERE SHOULD TOP OUT IN THE 70S AWAY FM SOME MODERATION ON MAINLY
THE E SIDE OF THE KEWEENAW IN LLVL SE FLOW. THIS SE FLOW WL TEND TO
LIMIT THE DIURNAL TEMP RISE OVER THE SE COUNTIES.
TNGT...THE UPR RDG AXIS IS FCST TO DRIFT ONLY SLOWLY TO THE E...WITH
SFC HI OVER QUEBEC DRIFTING S INTO NEW ENGLAND. WITH FALLING MSLP IN
THE PLAINS ASSOCIATED WITH SHRTWV LIFTING OUT OF THE WRN TROF...THE
PRES GRADIENT/SLY FLOW IS PROGGED TO SHARPEN OVER MAINLY WRN UPR MI.
THIS INCRSG S WIND IN CONCERT WITH FCST INCRSG PWAT WL RESTRICT THE
DIURNAL TEMP FALL IN THIS AREA...SO TENDED TOWARD THE WARM SIDE OF
GUIDANCE FOR MIN TEMPS OVER THE FAR W FM IWD INTO THE KEWEENAW. A
FLATTER PRES GRADIENT/PWAT FCST AOB 0.50 INCH CLOSER TO THE SFC HI
TO THE E WL SUPPORT LOWER TEMPS OVER THE INTERIOR E HALF...AND FCST
LO TEMPS CLOSER TO THE LO END OF GUIDANCE IN THIS AREA. BUT SOMEWHAT
STRONGER H925 WINDS UP TO 20KTS FCST IN THIS AREA WL LIKELY KEEP THE
LOWS A BIT HIER THAN OBSVD THIS MRNG. WITH THE S WIND OFF LK MI...
EXPECT MORE FOG TO FORM IN THIS AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 406 AM EDT THU SEP 26 2013
FRIDAY WILL BE THE LAST COMPLETELY DRY DAY ACROSS THE CWA AS THE
HIGH PRESSURE RIDGE THAT HAS BEEN INFLUENCING OUR WEATHER SLIDES
SOUTHEAST INTO THE ATLANTIC STATES. AT THE SAME TIME...THE UPPER
TROUGH CURRENTLY OVER THE WESTERN CONUS WILL EJECT OUT OF THE
ROCKIES AND INTO THE CENTRAL AND NORTHERN PLAINS. A SHORTWAVE
EXITING THIS UPPER TROUGH WILL MOVE NORTHEAST THROUGH THE CANADIAN
PRAIRIES WITH AN ASSOCIATED SURFACE LOW THAT LEAVE AN ELONGATED
SURFACE TROUGH STRETCHING SOUTH THROUGH MINNESOTA AND INTO THE
CENTRAL PLAINS. SINCE THAT WILL BE THE MAIN FOCUS OF THE
PRECIPITATION ON FRIDAY AND THE AREA STILL UNDER THE DRY AIR OF THE
HIGH...SHOULD SEE ANOTHER MOSTLY SUNNY DAY ACROSS THE CWA. LATE IN
THE AFTERNOON...COULD SEE SOME MID-HIGH CLOUDS AFFECTING WESTERN
UPPER MICHIGAN. WITH THE SUNSHINE...SHOULD SEE ANOTHER DAY OF ABOVE
NORMAL HIGHS WITH TEMPERATURES IN THE UPPER 60S TO MIDDLE 70S. IT
SHOULD BE A LITTLE BREEZY ON FRIDAY DUE TO THE INCREASING PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING TROUGH...ESPECIALLY
OVER THE WEST WHERE THERE COULD BE GUSTS TO 25-30MPH. EXPECT BREEZY
CONDITIONS TO CONTINUE AT TIMES FRIDAY NIGHT INTO SATURDAY UNTIL
THE FRONT MOVES THROUGH.
THIS DRY AIR WILL REMAIN THROUGH FRIDAY NIGHT AND INTO SATURDAY
MORNING...WITH ONLY A FEW SHOWERS BRUSHING FAR WESTERN LAKE
SUPERIOR DURING THAT TIME. THEN...AS THE UPPER TROUGH EJECTS OUT OF
THE FOUR CORNERS REGION FRIDAY NIGHT...IT PULLS THE ENTIRE UPPER
TROUGH WITH IT AND THROUGH THE UPPER GREAT LAKES REGION THROUGH
SUNDAY. IN ADDITION...A SECONDARY LOW WILL DEVELOP ALONG THE TROUGH
NEAR WESTERN LAKE SUPERIOR AND THE MN ARROWHEAD AS THE RIGHT REAR
OF THE UPPER JET SLIDES NORTHEAST THROUGH THE AREA. THIS WILL ALLOW
A LINE OF SHOWERS ORIENTATED NORTH-SOUTH ALONG AND BEHIND THE
TROUGH TO MOVE EAST-NORTHEAST ACROSS UPPER MICHIGAN. AS HAS BEEN THE
CASE OVER THE LAST SEVERAL NIGHT...THE GFS REMAINS THE FASTEST WITH
THE ARRIVAL OF THE TROUGH/SHOWERS...WHILE THE GEM/ECMWF ARE MORE
CONSISTENT WITH THE SLOWER ARRIVAL. THE NAM ALSO FOLLOWS ALONG WITH
THE FASTER ARRIVAL SHOWN IN THE GFS. SINCE THERE IS AN EVEN SPLIT IN
ARRIVAL TIMES AND ONLY 50-75MI SPREAD...WILL SPLIT THE DIFFERENCE
AT THIS POINT AND HAVE THE WESTERN THIRD/HALF OF UPPER MICHIGAN
SEEING RAIN BY SUNSET AND THEN IT SPREADING ACROSS THE REST OF THE
CWA SATURDAY EVENING. WITH THE DIFFERENCES IN SPEED...ALSO FOLLOWED
THE SIMILAR IDEA FOR THE BACK SIDE OF THE RAIN OVERNIGHT SATURDAY.
STILL APPEARS LIKE A DECENT OPPORTUNITY FOR A QUARTER INCH OF RAIN
OVER MUCH OF THE CWA...ALTHOUGH IT WILL LIKELY FALL IN A 2-3HR
PERIOD. FINALLY...THUNDER POTENTIAL STILL LOOKS TO BE VERY
LIMITED...ESPECIALLY WITH MUCH OF THE RAIN EXPECTED TO BE
POST-FRONTAL. THERE ARE A COUPLE SMALL POCKETS OF 700-500MB LAPSE
RATES APPROACHING 6.5C/KM AHEAD OF THE FRONT AND SIMILAR POCKETS OF
MUCAPE NEAR 250 J/KG. IF A RUMBLE OF THUNDER OCCURS...BELIEVE IT
WOULD BE IN THE WESTERN U.P. IN THE AFTERNOON. BUT...SINCE COVERAGE
SHOULD BE VERY ISOLATED...OPTED TO REMOVE THE SLIGHT CHANCE OF
THUNDER.
WEAK UPPER RIDGE WILL QUICKLY BUILD IN ON SUNDAY AFTERNOON AND
REMAIN INTO MONDAY. THIS WILL LEAD TO ANOTHER DRY PERIOD OF
WEATHER. THERE MAY BE A SOME POST-FRONTAL CLOUDS SUNDAY AFTERNOON
AS A POCKET OF COOLER TEMPERATURES ALOFT MOVE THROUGH. ECMWF/GEM
SEEM TO LIKE THAT IDEA...WHILE GFS KEEPS THINGS CLEAR. SINCE THAT
MOISTURE AND COOLER AIR WILL BE QUICKLY PULLING OUT ON
SUNDAY...WITH FOLLOW THE GENERAL IDEA OF DECREASING CLOUDS ON
SUNDAY. HIGHS WILL BE COOLER ON SUNDAY WITH THAT COLD POCKET OF
AIR...BUT STILL THINK THEY WILL END UP IN THE LOWER-MID 60S IN MOST
LOCATIONS (WHICH IS NORMAL FOR THIS TIME OF YEAR). TEMPERATURES
SHOULD WARM BACK ABOVE NORMAL ON MONDAY WITH HIGHS IN THE UPPER 60S
AND LOWER 70S...AS 850MB TEMPERATURES PUSH BACK INTO THE LOWER
TEENS.
CONUS LOOKS TO COME UNDER ZONAL FLOW FOR TUESDAY AND PART OF
WEDNESDAY...AS THE UPPER JET RUNS WEST-EAST ACROSS THE NORTHERN
ROCKIES. THIS SHOULD KEEP THE MAIN SYNOPTIC FEATURES LOCKED IN
CANADA AND POSSIBLY JUST BRUSHING THE AREA AT TIMES MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL ALSO KEEP THE AREA UNDER ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 131 AM EDT THU SEP 26 2013
MAIN FOCUS FOR THE PERIOD IS THE POTENTIAL FOR ANOTHER ROUND OF
NOCTURNAL FOG EARLY THIS MRNG. THE MAIN LIMITING FACTOR AGAINST
SGNFT FOG FORMATION IS THE VERY DRY LLVL AIR SHOWN ON THE 00Z APX
RAOB. MODELS IN GOOD AGREEMENT SHOWING SE FLOW ARND SFC HI PRES OVER
CANADA ADVECTING THIS DRIER AIR INTO UPR MI. SO ALTHOUGH THERE MAY
BE SOME SHALLOW FOG AT MAINLY SAW WITH AN UPSLOPE WIND COMPONENT...
IFR CONDITIONS EVEN THERE LOOK TO BE TRANSIENT. DOWNSLOPE NATURE OF
THE LLVL FLOW IN TANDEM WITH THE NEAR SFC DRY ADVECTION WL PROBABLY
KEEP FOG FM FORMING AT IWD AND RESTRICT INTENSITY AS WELL AT CMX.
ANY FOG WL ERODE QUICKLY AFTER SUNRISE AND GIVE WAY TO VFR WX WITH
THE HI PRES DOMINATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EDT THU SEP 26 2013
HIGH PRESSURE OVER WESTERN QUEBEC WILL CONTINUE TO DOMINATE THE
WEATHER FOR TODAY...ALTHOUGH IT WILL BEGIN TO SLIDE SOUTHEAST
TONIGHT. BEFORE THIS OCCURS...THERE IS AN AREA OF FOG (LOCALLY
DENSE) OVER THE WESTERN LAKE EARLY THIS MORNING AND EXPECT THAT TO
DIMINISH THIS MORNING AS DRIER AIR SLIDES IN FROM THE SOUTHEAST.
MEANWHILE...A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE
NORTHERN PLAINS TODAY WILL LINGER A TROUGH EASTERN DAKOTAS TONIGHT
AND THEN SLOWLY MOVE EAST ACROSS MINNESOTA ON FRIDAY. AS THIS
OCCURS...THE PRESSURE GRADIENT AND THUS SOUTHERLY WINDS WILL
INCREASE OVER LAKE SUPERIOR ON FRIDAY. THESE STRONGER WINDS...TO
25KTS...WILL CONTINUE FRIDAY NIGHT AND SATURDAY UNTIL THE TROUGH
MOVES THROUGH LATE SATURDAY AFTERNOON AND EVENING. BEHIND THE
TROUGH...THERE COULD BE A BRIEF PERIOD OF STRONGER WESTERLY WINDS TO
25KTS OVER NORTH CENTRAL LAKE SUPERIOR OVERNIGHT SATURDAY NIGHT INTO
EARLY SUNDAY MORNING. WEAK HIGH PRESSURE WILL BUILD IN TO THE UPPER
GREAT LAKES ON SUNDAY NIGHT AND MONDAY AND LOWER WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
715 PM CDT FRI SEP 27 2013
.SYNOPSIS...
ISSUED AT 330 PM CDT FRI SEP 27 2013
A HIGHLY AMPLIFIED UPPER AIR PATTERN IS IN PLACE THIS
AFTERNOON...WITH A RIDGE EXTENDING FROM THE GULF OF MEXICO UP INTO
THE GREAT LAKES AND A DEEP TROUGH EXTENDING DOWN THE ERN EDGE OF THE
ROCKIES.
AT THE SFC...CYCLOGENESIS HAS BEEN TAKING PLACE ACROSS SE COLORADO
TODAY...WHERE BETWEEN 12Z AND 19Z WE HAVE SEEN A 1001 MB LOW DEEPEN
INTO A 997 MB LOW. AT 3 PM...A MORE OR LESS STATIONARY FRONT
EXTENDED FROM THE COLORADO LOW NORTHEAST ACROSS ERN SODAK AND OFF TO
NEAR LAKE OF THE WOODS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 330 PM CDT FRI SEP 27 2013
SATELLITE IMAGERY THIS AFTERNOON IS SHOWING LIFT AHEAD OF THE
ROCKIES WAVE BEGINNING TO INCREASE AS CLOUD TOPS BEGIN TO COOL FROM
NW KS UP INTO SE SODAK. THIS IS THE BEGINNINGS OF THE POST FRONTAL
BAND OF FGEN INDUCED PRECIP THAT ALL MODELS SHOW DEVELOPING THIS
EVENING...WEST OF THE MPX AREA. BESIDE THE COOLING CLOUD
TOPS...SATELLITE ALSO SHOWING CLEARING RAPIDLY MOVING NORTH ACROSS
MN AND WE HAVE REALLY SEEN WINDS/TEMPS RESPOND TO THE
CLEARING...WITH FAIRMONT HITTING 88 AT 3 PM...ALONG WITH GUSTS
ACROSS SOUTH CENTRAL MN ALSO APPROACHING 40 MPH.
BIGGEST CHANGE MADE TO THE FORECAST WAS TO SLOW DOWN THE ARRIVAL OF
PRECIP TONIGHT. THE REASON IS THAT THE FRONT AND ITS ASSOCIATED FGEN
BAND DO NOT LOOK TO MOVE EAST UNTIL THE UPPER WAVE BEGINS TO EJECT
ACROSS THE PLAINS...WHICH DOES NOT BEGIN TO HAPPEN UNTIL AFTER 6Z.
GIVEN STRONG FORCING ASSOCIATED WITH THIS WAVE...SEEING STRONG
AGREEMENT AMONG HIRES MODELS...WITH EVERYTHING FROM THE HOPWRF
MEMBERS TO YOUR SPC/NMM/ARW WRFS SHOWING RAIN NOT BEGINNING TO MOVE
INTO WRN MN UNTIL ALMOST 9Z. THOUGHT ORIENTATION OF INHERITED POPS
FOR TONIGHT THROUGH SATURDAY LOOKED GOOD...SO MAINTAINED THE LOOK OF
THE POP GRIDS...JUST SLOWED THINGS DOWN BY 3 OR 4 HOURS TODAY.
HAVE MAINTAINED SOME CHANCE POPS IN THE NW CWA BETWEEN 00Z AND 06Z
AS THE HRRR CONTINUES TO SHOW SCATTERED CONVECTION DEVELOPING ALONG
THE COLD FRONT BETWEEN 00Z AND 02Z...BUT THE MAIN SHOW PRECIPITATION
WISE IS COMING LATE TONIGHT. IF WE DO GET CONVECTION TO FIRE AS THE
HRRR SUGGESTS...DO NOT ANTICIPATE ANY OF IT WILL BE SEVERE THANKS TO
SBCAPES LESS THAN 1000 J/KG. WOULD NEED MORE ROBUST INSTABILITY TO
GET MUCH MORE OF A SEVERE THREAT.
FOR TONIGHT...WAS TEMPTED TO REMOVE ANY THUNDER MENTION FROM THE
FORECAST SINCE FOR THE MOST PART THIS WILL JUST BE RAIN. BUT WILL
LIKELY HAVE A FEW RUMBLES OF THUNDER AS THE BAND MOVES THROUGH...SO
MAINTAINED THE ISO THUNDER WORDING.
FOR QPF...MODEL CONSENSUS HAS REMAINED QUITE HIGH IN 0.3-0.5 INCHES
FALLING ACROSS MOST OF THE AREA...SO KEPT THE QPF FORECAST CLOSE TO
A WPC/MODEL BLEND.
FINALLY FOR TEMPERATURES...BEING OUT AHEAD OF THE FRONT WE WILL HAVE
ANOTHER MILD NIGHT...WITH MUCH OF THE AREA ONLY FALLING BACK INTO
THE MID 60S FOR LOWS...WHICH IS RIGHT ABOUT NORMAL...FOR HIGHS THIS
TIME OF YEAR! FOR SATURDAY...USED THE NAM TO RUN THE DIURNAL TREND
FOR TEMPERATURES...WHICH RESULTED IN FALLING TEMPERATURES DURING THE
MORNING AND AFTERNOON IN THE ERN CWA AS THE BAND OF RAIN MOVES FROM
ERN MN INTO WRN WI.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 PM CDT FRI SEP 27 2013
AFTER SATURDAY SYSTEM MOVES ACROSS THE UPPER MIDWEST...THE MEAN
FLOW AND ASSOCIATED MOISTURE AND SFC FEATURES WILL BE WELL INTO
CANADA LEADING TO A DRY PERIOD THRU THE MIDDLE OF NEXT WEEK.
OVER THE PAST WEEK OR TWO...THE PACIFIC NW HAS BEEN VERY WET DUE
TO A PERSISTENT ONSHORE FLOW WHICH IS EXPECTED THRU THE EARLY PART
OF NEXT WEEK. OUR REGION WILL HOLD ONTO A MORE FAST WEST TO EAST
FLOW...WITH THE CENTRAL U.S. AND THE SE MUCH WARMER AS AN UPPER
LEVEL RIDGE BEGINS TO BUILD. THE MEAN LONG WAVE TROUGH ACROSS
WESTERN PART OF NORTH AMERICA IS EXPECTED TO TRANSITION TO A WEAK
UPPER RIDGE /PACIFIC NW/...WHICH IS A DRY WEATHER PATTERN.
BETWEEN THE RIDGE IN THE SE...AND THE PACIFIC NW...THE LONG WAVE
TROUGH IS EXPECTED TO MOVE ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS BY LATE NEXT WEEK. BASICALLY THIS IS A WETTER PATTERN FOR
THE UPPER MIDWEST AS MOISTURE FROM THE GULF BEGINS TO INTERACT
WITH A POWERFUL JET STREAM PROGGED TO BE ACROSS THE NORTHERN U.S.
THE UPPER JET ALONE WILL LEAD TO A BETTER CHC OF CYCLOGENESIS
DEVELOPING IN THE PLAINS /INCREASING MOIST FROM THE GULF/ AND AN
INCREASE IN PRECIPITATION CHC/S. THE MAIN UNCERTAINTY IS TIMING OF
THIS PATTERN CHG...ESPECIALLY IN REGARDS TO SFC FEATURES. BOTH THE
GFS/EC HAVE A SIMILAR PATTERN LATE NEXT WEEK...BUT THE DIFFERENCES
ARISE IN THE AMPLIFICATION. THE GFS IS MORE AMPLIFIED...ESPECIALLY
BY FRIDAY WITH A CUT OFF SYSTEM ACROSS THE WESTERN GREAT LAKES.
THE EC IS MORE PROGRESSIVE...BUT HAS THE SAME LONG WAVE TROUGH IN
THE NORTHERN U.S. THE GFS ENSEMBLE MEAN OF THE 50H PATTERN SEEMS
TO BE MORE IN LINE OF A DEEPER TROUGH...AND BETTER UPPER LEVEL
FORCING FOR THE UPPER MIDWEST. WILL HOLD ONTO THE CHC/LIKELY POPS
FOR THU/FRI OF NEXT WEEK. HOWEVER...TRENDS OF THE MODELS WILL
DICTATE THE STRENGTH AND SPEED ONCE THE PATTERN BEGINS TO CHG
EARLY NEXT WEEK.
A FINAL NOTE...BOTH THE GFS/EC DOES SHOW A SIGNIFICANT COOL DOWN
ONCE THIS PATTERN DEVELOPS AND MOVES THRU THE WEEKEND OF OCTOBER
5TH. 85H TEMPS FRIDAY NIGHT ARE COLD ENOUGH FOR SNOW IN THE
ARROWHEAD OF MN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 715 PM CDT FRI SEP 27 2013
SHOWERS LIFTING THROUGH WEST CENTRAL MN EARLY THIS EVENING...AND
OF THE TAF SITES...THE RAIN SHOULD ONLY AFFECT KAXN THROUGH 03Z.
FRONT HAS PASSED ELBOW LAKE MN BUT WITH SSW UPPER FLOW... FRONT
WILL BE SLOW TO ADVANCE ANOTHER 25-30 MILES INTO KAXN...BUT THAT
SHOULD TAKE PLACE LATER THIS EVENING. MAIN SHIELD OF PRECIP
EXTENDS FROM CENTRAL NEBRASKA TO THE SD/ND/MN BORDER AND INTO NWRN
MN. THIS WILL TAKE A LONG TIME TO REACH MN/WI BORDER...MAYBE NOT
UNTIL 16Z AT KRNH. ONCE IT MOVES IN...RAIN SHOULD PERSIST 5-8
HOURS. SHOULD SEE SOME MVFR VSBY/CIGS FOR SEVERAL HOURS WITH THE
HEAVIER RAIN. CONFIDENCE IN THE OCCURRENCE OF CONDITIONS IS ABOVE
AVERAGE BUT CONFIDENCE IN TIMING IS ONLY AVERAGE. IF TIMING
DIFFERS...IT WOULD LIKELY BE AN HOUR OR TWO SLOWER TO ARRIVE THAN
FORECAST.
KMSP...SSE WINDS WILL PERSIST OVERNIGHT...GENERALLY AT LEAST 10
KNOTS WITH GRADIENT IN PLACE. MAIN PRECIP WILL BE COMING LATER
SATURDAY MORNING INTO EARLY AFTERNOON. SOME POTENTIAL FOR
INCOMING RAIN AND MVFR VSBY/CIGS TO BE DELAYED UNTIL 17Z BUT THINK
15Z IS THE MORE LIKELY SCENARIO. HAVE KEPT CIGS ABOVE 017...BUT
THERE MAY BE A FEW HOURS DURING THE MIDDAY WHEN CIGS AROUND 015
ARE POSSIBLE.
/OUTLOOK FOR KMSP/
.SUN...VFR. WINDS SW 5-10 KTS.
.MON...VFR. WINDS S 10-20 KTS.
.TUE...VFR. WINDS SW-W 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...JLT
AVIATION...TDK
AREA FORECAST DISCUSSION
NWS DULUTH MN
317 AM CDT THU SEP 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 315 AM CDT THU SEP 26 2013
MAIN CHALLENGES IN THE SHORT TERM ARE CENTERED AROUND THE DENSE
FOG AROUND LAKE SUPERIOR THIS MORNING...THE GUSTY SE WINDS
EXPECTED THIS AFTERNOON...AND COOLER AFTERNOON TEMPERATURES
AROUND THE LAKE. THE FOCUS LATE TONIGHT AND THROUGH THE DAY FRIDAY
THEN SHIFTS TO PRECIP CHANCES MOVING IN WITH THE NEXT LOW PRESSURE
SYSTEM APPROACHING FROM THE SW.
UPPER LEVEL RIDGE AMPLIFYING OVER THE WRN GREAT LAKES THIS MORNING
AS WEAK HIGH PRESSURE AT THE SFC TO THE EAST SLOWLY ADVANCES OUT
OF THE AREA. A DEEPENING LONGWAVE TROUGH OVER THE INTER-MOUNTAIN
WEST IS EJECTING A FEW SHRT WVS INTO THE NRN PLAINS THIS MORNING
AND TRIGGERING A FEW SHOWERS AND STORMS ALONG A N-S ORIENTED
FRONTAL ZONE EXTENDING FROM FAR SERN SASKATCHEWAN INTO THE WRN
DAKOTAS AND WRN NEB. A FEW HIGH CLOUDS ARE STREAMING IN ACROSS THE
FAR WRN COUNTIES OF THE CWA...BUT THE MAIN CONCERN THIS MORNING IS
THE AREAS OF FOG...DENSE IN SOME LOCATIONS...AROUND LAKE SUPERIOR.
A DENSE FOG ADVISORY WAS ISSUED YESTERDAY FOR THE PERIPHERY OF THE
LAKE...HOWEVER ENOUGH DRY AIR ENTRAINMENT AND MIXING THROUGH THE
OVERNIGHT HAS ALLOWED A GOOD PORTION OF THE FOG TO ADVECT AWAY
FROM THE SOUTH SHORE...AND LEAVE THE MAIN AREA OF DENSE FOG
CONFINED TO THE NORTH SHORE. SO...DECIDED TO CANCEL THE ADVISORY
FOR THE SOUTH SHORE AND LET IT RIDE FROM DULUTH TO GRAND PORTAGE
UNTIL 9 AM. THERE IS ALSO AN AREA OF FOG DEVELOPING IN N-CNTRL WI
WITHIN THE LAST HOUR...WILL NEED TO WATCH THIS AS THE MORNING
PROGRESSES.
AN INITIAL BATCH OF HIGH CLOUDS ASSOCIATED WITH A PASSING S/W
THROUGH THE NRN PLAINS WILL LIFT NWD TODAY AND LEAVE MUCH OF THE
AREA UNDER MOSTLY SUNNY SKIES. A FEW LOW CLOUDS COULD LINGER ALONG
THE NORTH SHORE UNDER THE INFLUENCE OF SE WINDS OFF THE LAKE.
STRONG MIXING THIS AFTERNOON...ESPECIALLY ACROSS NE MN WILL ALLOW
WINDS TO INCREASE OUT OF THE S/SE. SHOULD SEE SUSTAINED WINDS
AROUND 15 TO 20 MPH...AND GUSTS UP TO 25 MPH. THE STRONGEST WINDS
WILL BE AROUND THE BRAINERD LAKES AREA...WITH LIGHTER WINDS
ELSEWHERE. STRONG WAA WILL ALSO ALLOW TEMPERATURES TO WARM WELL INTO
THE 70S. THE EXCEPTION WILL BE ALONG THE NORTH SHORE WHERE A LAKE
BREEZE WILL KEEP TEMPS IN THE UPPER 50S AND LOWER 60S.
ADDITIONAL CLOUD COVER WILL MOVE IN TONIGHT AS THE UPPER TROUGH
MOVES THROUGH THE SRN ROCKIES AND A SFC LOW DEVELOPS OVER THE SRN
PLAINS AND LIFTS NEWD INTO THE UPPER MIDWEST. THIS SFC FEATURE
WILL MOVE NEWD INTO THE NORTHLAND AS AN ELONGATED SFC TROUGH AND
PRODUCE SHOWERS AND THUNDERSTORMS THROUGH THE DAY FRIDAY. THE BEST
CHANCE FOR STORMS WILL BE IN THE AFTERNOON WHEN THE SFC FRONT
INTERACTS WITH ENOUGH BL INSTABILITY TO PRODUCE MODERATE CONVECTION.
TEMPERATURES WILL WARM INTO THE 70S AND LOWER 80S ON FRIDAY...AS
LOW LEVEL MOISTURE INCREASES AND LAPSE RATES STEEPEN OVER CENTRAL
AND NRN MN. SECTIONS OF NE MN ARE HIGHLIGHTED IN THE SPC DAY 2
CONVECTIVE OUTLOOK.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 315 AM CDT THU SEP 26 2013
NAM/GFS ARE THE QUICKEST WITH THE SFC LOW/COLD FRONT THAT WILL
AFFECT THE FA FRIDAY NIGHT THROUGH SATURDAY NIGHT. ECMWF/GEM ARE
SLOWER AND PREFERRED WITH THE HANDLING OF THIS SYSTEM. RAIN SHOULD
REACH THE WESTERN THIRD OF THE FA FRIDAY EVENING AND FALL MAINLY
WEST OF HIGHWAY 53 THROUGH THE REST OF FRIDAY NIGHT. WILL STILL
CARRY A MENTION OF ISOLD THUNDER WITH WEAK INSTABILITY. ON
SATURDAY...RAIN WILL PROGRESS ACROSS THE ENTIRE FA...BUT NOT
REACHING THE TIP OF THE ARROWHEAD AND EASTERN PORTION OF WI COUNTIES
UNTIL AFTERNOON. WHAT INSTABILITY WAS AVAILABLE HAS NOW DIMINISHED
AND WILL CARRY A MENTION OF ALL RAIN. THE COLD FRONT WILL MOVE
QUICKLY THROUGH THE AREA SATURDAY EVENING AND EXIT BY 12Z SUNDAY.
HAVE LINGERED SOME POPS SATURDAY EVENING OVER THE NORTH AND EAST IN
THE VCNTY OF THE FRONT AND SFC LOW AND REMOVED FROM THE OVERNIGHT. A
DRY PERIOD IS IN STORE SUNDAY THROUGH MONDAY NIGHT. MODEL
DIFFERENCES SHOW UP WITH A COLD FRONT MOVING ACROSS THE WESTERN
GREAT LAKES ON TUESDAY AND ASSOCIATED RAIN. HAVE GONE WITH A
COMPROMISE FOR POPS. DRY CONDITIONS RETURN TUESDAY NIGHT AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1150 PM CDT WED SEP 25 2013
STRATUS AND FOG AROUND LAKE SUPERIOR CONTINUED TO EXPAND WEST AND
NORTH LATE THIS EVENING...WITH THE STRATUS DIMINISHING IN COVERAGE
FROM THE EAST. THE MEAN LOW LEVEL FLOW IS FORECAST TO VEER TO MORE
SOUTHERLY TONIGHT AND INCREASE. THIS SHOULD HELP PUSH THE FOG AND
LOWER CEILINGS NORTH...AND WILL CAUSE THEM TO DIMINISH ALONG THE
SOUTH SHORE...PERHAPS INTO KDLH AS WELL LATE. THE HRRR IS PICKING UP
ON THIS TREND LATER TONIGHT. AT THIS TIME...WE KEPT LIFR CONDITIONS
IN THE KDLH TAF AS CONFIDENCE ON WHEN/IF CONDITIONS IMPROVE IS LOW.
MUCH OF THE FOG/STRATUS WILL LIFT BY 15Z...LINGERING LONGER ALONG
THE NORTH SHORE. GUSTY SOUTHEAST/SOUTH WINDS WILL DEVELOP DURING THE
DAY THURSDAY WITH VFR CONDITIONS. KBRD SOUNDING SHOWS 34KT AT THE
TOP OF THE MIXED LAYER AROUND 870MB.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 68 57 75 59 / 0 0 30 20
INL 76 59 71 53 / 0 10 70 80
BRD 79 63 73 57 / 0 20 60 80
HYR 74 54 77 61 / 0 0 10 10
ASX 72 55 78 61 / 0 0 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ020-021-
037.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...BJT
LONG TERM...GSF
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1152 PM CDT WED SEP 25 2013
.UPDATE...
ISSUED AT 1150 PM CDT WED SEP 25 2013
FOG AND STRATUS CONTINUED LATE THIS EVENING AROUND LAKE
SUPERIOR...ESPECIALLY FROM ABOUT ASHLAND TO THE TWIN PORTS TO
GRAND RAPIDS AND NORTHEAST ALONG THE NORTH SHORE. THE CLOUDS/FOG
WAS EXPANDING ACROSS THE RANGE AS WELL. THE LOW LEVEL FLOW IS
FORECAST TO VEER TO MORE SOUTH/SOUTHEAST OVERNIGHT AND INCREASE.
THIS WILL CAUSE THE STRATUS/FOG TO RETREAT/DISSIPATE ACROSS
PORTIONS OF THE SOUTH SHORE LATER TONIGHT. THIS MAY ALSO MAKE IT
INTO THE TWIN PORTS LATE. AT THIS TIME...WE`LL LEAVE THE DENSE FOG
ADVISORY AS IS...BUT LATER SHIFTS MAY BE ABLE TO CUT BACK THE
SOUTHERN PORTION.
&&
.SYNOPSIS...
ISSUED AT 328 PM CDT WED SEP 25 2013
LAKE SUPERIOR DOMINATED BY LOW STRATUS/FOG LAYER WHILE INLAND
AREAS ARE SUNNY UNDER A DRY AIR MASS AND HIGH PRESSURE. MAJOR
UPPER TROF OVER INTERMOUNTAIN WEST IS AMPLIFYING COURTESY OF 140KT
UPPER JET ON SWRN FLANK OF CIRCULATION. A SWRLY MID LVL FLOW IS
CURRENTLY IN PLACE ACROSS THE CWA. AN AREA OF MID CLOUDS
ASSOCIATED WITH A WEAK SHORTWAVE FEATURE ALOFT IS MOVING INTO THE
WRN CWA. WARM ADVECTION REGIME CONTINUES TO INCREASE OVER THE CWA
AS CYCLOGENESIS IS UNDERWAY OVER WRN HI PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 328 PM CDT WED SEP 25 2013
TONIGHT...EXPECT AREA OF CLOUDS/FOG OVER LAKE SUPERIOR TO ADVECT
INLAND AS SFC HEATING DECREASES. LATEST HRRR 3KM SHOWS HIGHEST PROB
OF LOWEST VIS ALONG NSHORE...TWIN PORTS...AND CHEQUAMEGON BAY.WILL
ISSUE A DENSE FOG ADVISORY CONSIDERING THE PRESENCE OF THE DENSE
FOG OVER THE LAKE AND ITS LIKELY PENETRATION INLAND. LATEST HI-RES
MDLS SUGGEST FOG BANK MAY TRY TO SHIFT FARTHER NORTH AND WEST
OVERNIGHT. ELSEWHERE WILL USE PATCHY FOG FOR POTENTIAL OF LIGHT
WINDS/SATURATION IN NEAR SFC LAYER.
TOMORROW...DENSE FOG EXPECTED TO PERSIST NEAR LAKE SUPERIOR
THROUGH EARLY MORNING. MAIN ISSUE TOMORROW WILL BE INCREASE IN
GUSTY SE WINDS. LATEST BUFKIT MOMENTUM PROFILES INDICATE GUSTS TO
35 AND POSSIBLY AN ISOLATED 40 MPH ARE POSSIBLE OVER NE MN ZONES BY
AFTN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 PM CDT WED SEP 25 2013
ON THURSDAY NIGHT...A SHARP UPPER LEVEL RIDGE WILL EXTEND THROUGH
THE CENTRAL PLAINS...INTO THE JAMES BAY AREA NEAR HUDSON BAY.
MEANWHILE...A LONGWAVE TROUGH WILL BE LOCATED IN THE FAR
SOUTHWESTERN UNITED STATES. IN BETWEEN WE WILL BE IN SW FLOW. THE
MODELS ARE HINTING AT A LOW PRESSURE SYSTEM DEVELOPING IN THE HIGH
PLAINS THURSDAY NIGHT AND FRIDAY...WITH A FRONT OR SURFACE TROUGH
EXTENDING NORTHEASTWARD INTO MINNESOTA. QPF AMOUNTS VARY...BUT THE
GENERAL CONSENSUS IS THAT THERE WILL BE SOME LIGHT PRECIPITATION
ACROSS THE MN SIDE OF OUR CWA. THE LONGWAVE TROUGH EDGES EASTWARD ON
FRIDAY...BRINGING A POTENTIALLY MORE SUBSTANTIAL CHANCE OF
PRECIPITATION TO THE CWA. THE BEST CHANCE OF RAIN AND EMBEDDED
THUNDERSTORMS WOULD BE IN THE MN SIDE ONCE AGAIN. A SHORTWAVE AND
UPPER LEVEL VORT MAX WILL LIFT INTO THE UPPER RED RIVER VALLEY AND
WESTERN GREAT LAKES REGION FRIDAY NIGHT AND SATURDAY...BRINGING A
WET PERIOD TO THE WESTERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE
GFS IS FASTEST AT PUSHING THE SYSTEM OUT OF THE AREA ON
SATURDAY...WITH THE GEM AND ECMWF BEING SLOWER. WILL USE A BLEND OF
THE ABOVE MODELS FOR THE MOST PART. BY SUNDAY...A MORE ZONAL FLOW
ESTABLISHES ITSELF ACROSS THE NORTH CENTRAL UNITED STATES. SUNDAY
INTO TUESDAY LOOKS LIKE IT WILL BE GENERALLY DRY ACROSS THE
REGION...WITH A CHANCE OF SHOWERS IN ONLY A FEW LOCATIONS THROUGH
WEDNESDAY AS WELL. TEMPERATURES WILL GENERALLY BE ABOVE NORMAL WITH
HIGHS IN THE 60S AND EVEN SOME LOWER TO MIDDLE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1150 PM CDT WED SEP 25 2013
STRATUS AND FOG AROUND LAKE SUPERIOR CONTINUED TO EXPAND WEST AND
NORTH LATE THIS EVENING...WITH THE STRATUS DIMINISHING IN COVERAGE
FROM THE EAST. THE MEAN LOW LEVEL FLOW IS FORECAST TO VEER TO MORE
SOUTHERLY TONIGHT AND INCREASE. THIS SHOULD HELP PUSH THE FOG AND
LOWER CEILINGS NORTH...AND WILL CAUSE THEM TO DIMINISH ALONG THE
SOUTH SHORE...PERHAPS INTO KDLH AS WELL LATE. THE HRRR IS PICKING UP
ON THIS TREND LATER TONIGHT. AT THIS TIME...WE KEPT LIFR CONDITIONS
IN THE KDLH TAF AS CONFIDENCE ON WHEN/IF CONDITIONS IMPROVE IS LOW.
MUCH OF THE FOG/STRATUS WILL LIFT BY 15Z...LINGERING LONGER ALONG
THE NORTH SHORE. GUSTY SOUTHEAST/SOUTH WINDS WILL DEVELOP DURING THE
DAY THURSDAY WITH VFR CONDITIONS. KBRD SOUNDING SHOWS 34KT AT THE
TOP OF THE MIXED LAYER AROUND 870MB.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 49 72 56 75 / 0 0 10 10
INL 50 75 57 69 / 0 0 10 70
BRD 53 81 61 72 / 0 0 10 40
HYR 43 74 57 79 / 0 0 0 10
ASX 46 72 57 78 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THURSDAY FOR MNZ020-021-037.
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THURSDAY FOR WIZ001>004.
LS...DENSE FOG ADVISORY UNTIL NOON CDT THURSDAY FOR LSZ121-140>148.
&&
$$
UPDATE...MELDE
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1258 PM EDT THU SEP 26 2013
.SYNOPSIS...
AN UPPER LEVEL WILL MOVE OFF THE CAROLINA COAST THIS AFTERNOON. HIGH
PRESSURE WILL BUILD IN FROM THE NORTH ON FRIDAY INTO SUNDAY.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...
AN UPPER LEVEL LOW CONTINUES TO ROTATE OVER THE CAROLINAS THIS
MORNING AND THE CURRENT RUN OF THE RAP MODELS SHOWS SOME STRONGER
POCKETS OF VORTICITY COMING OUT OF SOUTHERN VA AND APPROACHING OUR
NORTHERN LOCALES. FURTHER INSPECTION OF SATELLITE AND RADAR DATA
SHOWS SOME LIGHT SHOWERS TRYING TO GAIN SOME COVERAGE AS THEY
APPROACH ROXBORO OVER THE NEXT COUPLE OF HOURS. RAP MODEL SHOWS THE
VORTICITY FIELD WEAKENING SO IT IS UNCLEAR WEATHER OR NOT THESE
SHOWERS WILL HOLD TOGETHER BUT AT LEAST SOME SPRINKLES COULD BE
POSSIBLE THROUGH EARLY AFTERNOON IN OUR NORTHERN COUNTIES. OTHERWISE
THE REST OF THE CWA WILL REMAIN DRY AS DRIER AIR WORKS IN FROM THE
SOUTHWEST AND THE LOW GRADUALLY MOVES OFF THE COAST. SOME MID LEVEL
CLOUDS CAN BE EXPECTED ACROSS THE AREA THROUGH AT LEAST EARLY
AFTERNOON WHICH MAY HELP TO KEEP TEMPERATURES DOWN A BIT. CURRENT
OBS SHOW TEMPERATURES IN THE MID 60S TO NEAR 70 AND MAX TEMPS ARE
EXPECTED TO TOP OUT IN THE MID 70S TO NEAR 80 IN THE SOUTHWEST WHERE
CLEARING WILL OCCUR A LITTLE QUICKER. -ELLIS
FOR TONIGHT: ON THE BACK SIDE OF THE DEPARTING MID LEVEL LOW... FLOW
ALOFT BECOMES NORTHERLY... WHILE LOWER LEVEL FLOW STAYS A BIT STOUT
FROM THE NORTHEAST AS THE MSLP GRADIENT TIGHTENS BETWEEN THE SURFACE
LOW OFF THE FL/GA COAST AND THE INCOMING NARROW SURFACE HIGH
PRESSURE RIDGE OVER THE EASTERN STATES. THIS FLOW WILL DRAW COOLER
CANADIAN AIR INTO CENTRAL NC... WITH THICKNESSES BOTTOMING OUT
AROUND 1365 M TOWARD MORNING. FORECAST SOUNDINGS SHOW A LOT OF
DRYING THROUGH THE COLUMN AND DEEPLY STABLE AIR... SO EXPECT MOSTLY
CLEAR SKIES... WITH A LIGHT NE WIND AS LOW LEVELS DECOUPLE. LOWS
52-56. -GIH
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 315 AM THURSDAY...
THE AMPLIFIED MID LEVEL RIDGING FROM LA UP THROUGH MI AND TROUGHING
OVER THE NW ATLANTIC WILL KEEP NC BENEATH A MODERATE NORTHERLY FLOW
ALOFT... WHILE NEAR THE SURFACE... THE CANADIAN HIGH CENTERED OVER
THE ST LAWRENCE VALLEY WILL CONTINUE TO NOSE NARROWLY SSW THROUGH
CENTRAL/WRN NC. AS SURFACE PRESSURES REMAIN LOW OFF THE SOUTHEAST
COAST... THE SOMEWHAT TIGHT MSLP GRADIENT WILL KEEP A STEADY
NORTHEAST FLOW INTO NC... STRONGER OVER THE COASTAL PLAIN TRENDING
WEAKER OVER THE TRIAD... MOST NOTABLE FROM LATE MORNING THROUGH
AFTERNOON WITH A FEW GUSTS POSSIBLE. THE COLUMN STAYS FAIRLY DRY AND
NEUTRAL TO SUBSIDING... HOWEVER MODELS SHOW A WAVE IN THE NORTHERLY
STEERING FLOW DROPPING TO THE SOUTH FROM NEW ENGLAND LATE TONIGHT
THROUGH THE NORTHEAST AND MIDATLANTIC STATES THROUGH FRIDAY INTO THE
EVENING. THIS SHOULD SERVE TO REINFORCE THE COLD AIR ADVECTION AND
BRING JUST ENOUGH 925-800 MB MOISTURE INTO THE AREA FOR PARTLY
CLOUDY SKIES IN THE AFTERNOON AND POTENTIALLY INTO THE NIGHT TOO...
AS THIS MOISTURE REMAINS TRAPPED BENEATH THE SUBSIDENCE INVERSION
ALOFT. THICKNESSES ABOUT 15 M BELOW NORMAL WITH SOME SUNSHINE
SUPPORTS HIGHS OF 73-78. LOWS 51-56 WITH FAIR SKIES. -GIH
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...
SATURDAY AND SUNDAY:
ALL INDICATORS SUGGEST THAT THE CLOSED UPPER LEVEL LOW OFF THE
MID-ATLANTIC COAST WILL REMAIN OFFSHORE AND PROVE OF LITTLE
CONSEQUENCE(AT LEAST OUTSIDE OF MARINE IMPACTS)...HELD AT BAY
BY A HIGH-AMPLITUDE-LOW WAVELENGTH UPPER RIDGE AXIS BUILDING
EASTWARD INTO THE CENTRAL/SOUTHERN APPALACHIANS. BETWEEN THESE
TWO FEATURES...A COOL NORTHEASTERLY WIND WILL PREVAIL THROUGH THE
WEEKEND...ANCHORED IN THE LOW-LEVELS BY A ~1025MB SURFACE HIGH
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. DRY AND SEASONABLY
COOL WITH LOW-LEVEL THICKNESSES A GOOD 15-20M BELOW NORMAL SATURDAY
AND SUNDAY MORNING. HIGHS 73 TO 78...WITH SUNDAY BEFORE THE WARMEST
DAY OF THE TWO. LOWS IN THE LOWER TO MID 50S.
MID/UPPER LEVEL SHORTWAVE TROUGH OVER THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER GREAT LAKES AND SOUTHEAST CANADA
THROUGH THE WEEKEND. AS THE BETTER SUPPORT ALOFT HEADS NORTH OF THE
BORDER...AN ALREADY SCARCE PRECIP SHIELD ACCOMPANYING THE
DISSIPATING COLD FRONT WILL LIKELY DRY OUT COMPLETELY ACROSS THE
MID-ATLANTIC STATES ON MONDAY...WITH SERIOUS DOUBTS IF THE FRONT
WILL EVER MAKE THIS FAR SOUTH. WILL LEAVE FORECAST DRY FOR NOW...
BUT SOME SMALL/ISOLATED CHANCES MAY NEED TO BE ADDED AT A LATER TIME
AS MODELS INDICATE THE POTENTIAL FOR SOME WEAK SOUTHERN STREAM
ENERGY TO MOVE THROUGH THE SOUTHEAST US TUESDAY AND INTO WEDNESDAY.
MEANWHILE...TEMPERATURES WILL STEADILY MODERATE THROUGH THE WEEK
WITH LOW-LEVEL THICKNESSES CLIMBING A GOOD 20 TO 25 METERS ABOVE
NORMAL BY MID-WEEK. HIGHS IN THE UPPER 70S TO MID LOWER 80S. LOWS IN
THE MID 50S TO LOWER 60S.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 100 PM THURSDAY...
24 HOUR TAF PERIOD: MODERATELY HIGH CONFIDENCE OF VFR CONDITIONS
THROUGHOUT THE TAF PERIOD WITH THE EXCEPTION BEING SOME BRIEF
SUB-VFR FOG OR LOW STRATUS...PREDOMINATELY IN THE EAST JUST BEFORE
12Z. WILL COVER THIS WITH A TEMPO IN THE TAFS AT RDU...FAY...AND
KRWI. RH CROSS SECTIONS SHOW KRWI THE MOST LIKELY TO ENCOUNTER
FOG/LOW STRATUS OVERNIGHT. OTHERWISE A PRETTY DRY FORECAST OUTSIDE
OF A FEW ROGUE SPRINKLES IN THE TRIAD AND POSSIBLY RDU A BIT LATER
THIS AFTERNOON AS A SHORTWAVE IMPULSE MOVES THROUGH THE NORTHERN
TIER OF THE AREA. WINDS ARE EXPECTED TO BE GUSTY THIS AFTERNOON AND
A FEW OBSERVATION SIGHTS ALREADY CONFIRMING THIS WITH 15-20 KNOTS
THE MAXIMUM GUST. WITH SURFACE HIGH OVER THE MID-ATLANTIC AND NEW
ENGLAND...WINDS WILL REMAIN NORTHEASTERLY THROUGH THE TAF PERIOD.
LONG TERM: VERY DRY FORECAST FOR THE LONG TERM WITH VERY HIGH
CONFIDENCE OF VFR CONDITIONS WITH THE EXCEPTION OF SOME BRIEF FOG IN
THE LATE NIGHT/EARLY MORNING HOURS THROUGH THE WEEKEND. WINDS WILL
REMAIN NORTHEASTERLY AND FAIRLY GUSTY IN THE AFTERNOON THROUGH
SATURDAY. SUSTAINED WIND SPEEDS OF 10 KNOTS GUSTING 15 TO 20 KNOTS
CAN BE EXPECTED BEFORE RELAXING ON SUNDAY AND BEYOND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...ELLIS/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...CBL
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1007 AM EDT THU SEP 26 2013
.SYNOPSIS...
AN UPPER LEVEL WILL MOVE OFF THE CAROLINA COAST THIS AFTERNOON. HIGH
PRESSURE WILL BUILD IN FROM THE NORTH ON FRIDAY INTO SUNDAY.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...
AN UPPER LEVEL LOW CONTINUES TO ROTATE OVER THE CAROLINAS THIS
MORNING AND THE CURRENT RUN OF THE RAP MODELS SHOWS SOME STRONGER
POCKETS OF VORTICITY COMING OUT OF SOUTHERN VA AND APPROACHING OUR
NORTHERN LOCALES. FURTHER INSPECTION OF SATELLITE AND RADAR DATA
SHOWS SOME LIGHT SHOWERS TRYING TO GAIN SOME COVERAGE AS THEY
APPROACH ROXBORO OVER THE NEXT COUPLE OF HOURS. RAP MODEL SHOWS THE
VORTICITY FIELD WEAKENING SO IT IS UNCLEAR WEATHER OR NOT THESE
SHOWERS WILL HOLD TOGETHER BUT AT LEAST SOME SPRINKLES COULD BE
POSSIBLE THROUGH EARLY AFTERNOON IN OUR NORTHERN COUNTIES. OTHERWISE
THE REST OF THE CWA WILL REMAIN DRY AS DRIER AIR WORKS IN FROM THE
SOUTHWEST AND THE LOW GRADUALLY MOVES OFF THE COAST. SOME MID LEVEL
CLOUDS CAN BE EXPECTED ACROSS THE AREA THROUGH AT LEAST EARLY
AFTERNOON WHICH MAY HELP TO KEEP TEMPERATURES DOWN A BIT. CURRENT
OBS SHOW TEMPERATURES IN THE MID 60S TO NEAR 70 AND MAX TEMPS ARE
EXPECTED TO TOP OUT IN THE MID 70S TO NEAR 80 IN THE SOUTHWEST WHERE
CLEARING WILL OCCUR A LITTLE QUICKER. -ELLIS
FOR TONIGHT: ON THE BACK SIDE OF THE DEPARTING MID LEVEL LOW... FLOW
ALOFT BECOMES NORTHERLY... WHILE LOWER LEVEL FLOW STAYS A BIT STOUT
FROM THE NORTHEAST AS THE MSLP GRADIENT TIGHTENS BETWEEN THE SURFACE
LOW OFF THE FL/GA COAST AND THE INCOMING NARROW SURFACE HIGH
PRESSURE RIDGE OVER THE EASTERN STATES. THIS FLOW WILL DRAW COOLER
CANADIAN AIR INTO CENTRAL NC... WITH THICKNESSES BOTTOMING OUT
AROUND 1365 M TOWARD MORNING. FORECAST SOUNDINGS SHOW A LOT OF
DRYING THROUGH THE COLUMN AND DEEPLY STABLE AIR... SO EXPECT MOSTLY
CLEAR SKIES... WITH A LIGHT NE WIND AS LOW LEVELS DECOUPLE. LOWS
52-56. -GIH
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 315 AM THURSDAY...
THE AMPLIFIED MID LEVEL RIDGING FROM LA UP THROUGH MI AND TROUGHING
OVER THE NW ATLANTIC WILL KEEP NC BENEATH A MODERATE NORTHERLY FLOW
ALOFT... WHILE NEAR THE SURFACE... THE CANADIAN HIGH CENTERED OVER
THE ST LAWRENCE VALLEY WILL CONTINUE TO NOSE NARROWLY SSW THROUGH
CENTRAL/WRN NC. AS SURFACE PRESSURES REMAIN LOW OFF THE SOUTHEAST
COAST... THE SOMEWHAT TIGHT MSLP GRADIENT WILL KEEP A STEADY
NORTHEAST FLOW INTO NC... STRONGER OVER THE COASTAL PLAIN TRENDING
WEAKER OVER THE TRIAD... MOST NOTABLE FROM LATE MORNING THROUGH
AFTERNOON WITH A FEW GUSTS POSSIBLE. THE COLUMN STAYS FAIRLY DRY AND
NEUTRAL TO SUBSIDING... HOWEVER MODELS SHOW A WAVE IN THE NORTHERLY
STEERING FLOW DROPPING TO THE SOUTH FROM NEW ENGLAND LATE TONIGHT
THROUGH THE NORTHEAST AND MIDATLANTIC STATES THROUGH FRIDAY INTO THE
EVENING. THIS SHOULD SERVE TO REINFORCE THE COLD AIR ADVECTION AND
BRING JUST ENOUGH 925-800 MB MOISTURE INTO THE AREA FOR PARTLY
CLOUDY SKIES IN THE AFTERNOON AND POTENTIALLY INTO THE NIGHT TOO...
AS THIS MOISTURE REMAINS TRAPPED BENEATH THE SUBSIDENCE INVERSION
ALOFT. THICKNESSES ABOUT 15 M BELOW NORMAL WITH SOME SUNSHINE
SUPPORTS HIGHS OF 73-78. LOWS 51-56 WITH FAIR SKIES. -GIH
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...
SATURDAY AND SUNDAY:
ALL INDICATORS SUGGEST THAT THE CLOSED UPPER LEVEL LOW OFF THE
MID-ATLANTIC COAST WILL REMAIN OFFSHORE AND PROVE OF LITTLE
CONSEQUENCE(AT LEAST OUTSIDE OF MARINE IMPACTS)...HELD AT BAY
BY A HIGH-AMPLITUDE-LOW WAVELENGTH UPPER RIDGE AXIS BUILDING
EASTWARD INTO THE CENTRAL/SOUTHERN APPALACHIANS. BETWEEN THESE
TWO FEATURES...A COOL NORTHEASTERLY WIND WILL PREVAIL THROUGH THE
WEEKEND...ANCHORED IN THE LOW-LEVELS BY A ~1025MB SURFACE HIGH
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. DRY AND SEASONABLY
COOL WITH LOW-LEVEL THICKNESSES A GOOD 15-20M BELOW NORMAL SATURDAY
AND SUNDAY MORNING. HIGHS 73 TO 78...WITH SUNDAY BEFORE THE WARMEST
DAY OF THE TWO. LOWS IN THE LOWER TO MID 50S.
MID/UPPER LEVEL SHORTWAVE TROUGH OVER THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER GREAT LAKES AND SOUTHEAST CANADA
THROUGH THE WEEKEND. AS THE BETTER SUPPORT ALOFT HEADS NORTH OF THE
BORDER...AN ALREADY SCARCE PRECIP SHIELD ACCOMPANYING THE
DISSIPATING COLD FRONT WILL LIKELY DRY OUT COMPLETELY ACROSS THE
MID-ATLANTIC STATES ON MONDAY...WITH SERIOUS DOUBTS IF THE FRONT
WILL EVER MAKE THIS FAR SOUTH. WILL LEAVE FORECAST DRY FOR NOW...
BUT SOME SMALL/ISOLATED CHANCES MAY NEED TO BE ADDED AT A LATER TIME
AS MODELS INDICATE THE POTENTIAL FOR SOME WEAK SOUTHERN STREAM
ENERGY TO MOVE THROUGH THE SOUTHEAST US TUESDAY AND INTO WEDNESDAY.
MEANWHILE...TEMPERATURES WILL STEADILY MODERATE THROUGH THE WEEK
WITH LOW-LEVEL THICKNESSES CLIMBING A GOOD 20 TO 25 METERS ABOVE
NORMAL BY MID-WEEK. HIGHS IN THE UPPER 70S TO MID LOWER 80S. LOWS IN
THE MID 50S TO LOWER 60S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 655 AM THURSDAY...
VSBYS HAVE VARIED BETWEEN MVFR AND VFR FOR MUCH OF THE NIGHT ACROSS
CENTRAL NC TAF SITES... HOWEVER BRIEF PERIODS OF IFR TO LIFR
CONDITIONS OCCURRED AT RWI AND GSO... WHERE SKIES BRIEFLY BECAME
MOSTLY CLEAR... ALLOWING DENSE FOG TO FORM QUICKLY IN THE DAMP AND
LIGHT WIND ENVIRONMENT. WITH THE ONSET OF HEATING AS THE SUN IS
RISING... THE ISOLATED PATCHES OF FOG SHOULD START TO MIX OUT... BUT
THE RISK OF SUB-VFR VSBYS WILL REMAIN POSSIBLE THROUGH ABOUT 13Z.
OTHERWISE... WE`LL CONTINUE TO SEE CONSIDERABLE MID CLOUDS AS A MID
LEVEL LOW PRESSURE AREA MOVES OVER THE REGION... ALTHOUGH MOST BASES
WILL BE ABOVE 7000 FT AGL. AREAS OF LIGHT RAIN MAY PASS NEAR RWI
THROUGH 15Z. ONCE THE STORM SYSTEM ALOFT SHIFTS EASTWARD OFF THE
CAROLINA COAST TODAY... EXPECT INCREASING SUNSHINE THROUGH THE DAY
AS MID LEVEL CLOUDS SLOWLY BREAK UP AND EXIT THE REGION... WHILE
SURFACE HIGH PRESSURE BEGINS TO NOSE IN FROM THE NORTH. VFR
CONDITIONS WILL HOLD WITH MOSTLY CLEAR SKIES AFTER 21Z... ALTHOUGH
SHALLOW BANKS OF FOG MAY START TO FORM AT RWI 06Z-08Z. SURFACE WINDS
WILL BE FROM THE NNE OR NORTHEAST AT SPEEDS OF 5-10 KTS DROPPING TO
UNDER 6 KTS BY SUNSET.
LOOKING BEYOND 12Z FRIDAY MORNING... SHALLOW FOG BANKS MAY BRING
BRIEF IFR CONDITIONS AT RWI THROUGH SUNRISE. OTHERWISE... HIGH
CONFIDENCE IN VFR CONDITIONS DOMINATING THROUGH MONDAY AS A RIDGE OF
HIGH PRESSURE HOLDS OVER NC. BRIEF SHALLOW SUB-VFR GROUND FOG MAY
OCCUR 08Z-12Z EACH MORNING... PRIMARILY AT RWI. WINDS FROM THE
NORTHEAST ARE EXPECTED EACH AFTERNOON FRIDAY THROUGH SUNDAY... NEAR
10 KTS AT INT/GSO AND A LITTLE STRONGER -- NEAR 15 KTS -- AT
RDU/RWI/FAY... WITH A TIGHT GRADIENT BETWEEN THE HIGH PRESSURE RIDGE
AND OFFSHORE LOW PRESSURE. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...ELLIS/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...CBL
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
935 PM CDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 933 PM CDT FRI SEP 27 2013
CONTINUE TO MAKE MINOR POP ADJUSTMENTS THROUGH REMAINDER OF THE
EVENING. STEADIER RAIN BAND NOW INTO FAR NW FA SO INCREASED POPS
THERE. ELSEWHERE SOLID RAIN BAND WITH ISOLD T STILL A FEW HOURS
FROM REACHING FAR SOUTHERN FA SO CURRENT POPS OK FOR NOW. NO OTHER
CHANGES MADE.
UPDATE ISSUED AT 637 PM CDT FRI SEP 27 2013
PRIMARY FOCUS THIS UPDATE WAS TO ADJUST POPS THROUGH THE EARLY TO
MID EVENING. MORE ORGANIZED -RA APPROACHING NW FA AND INCREASED
POPS THROUGH THE EVENING THIS AREA. ELSEWHERE PCPN MORE SPOTTY
WITH MAIN RAIN BAND MOVING INTO SOUTHERN FA LATER THIS EVENING.
MADE POP ADJUSTMENTS ACCORDINGLY THESE AREAS. T THREAT AT THIS POINT
LOOKS MINIMAL. NO OTHER CHANGES NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 314 PM CDT FRI SEP 27 2013
THE CHALLENGE WILL BE RAIN CHANCES AND AMOUNTS. EVERYTHING YOU
HAVE READ IN THE PAST COUPLE DAYS (SEE PREVIOUS FORECAST
DISCUSSIONS) IS STILL VALID AND THE FORECAST IS UNFOLDING
ACCORDING TO PLAN. THE 12Z NAM IS A BIT FURTHER WEST WITH THE MAIN
BAND OF RAIN TONIGHT...AND THE RAP IS ALSO WEST. WILL CONTINUE TO
FOLLOW THE MOST CONSISTENT ECMWF (WHICH MOSTLY IS IN AGREEMENT
WITH THE GFS AND GEM). THERE WILL BE AREAS OF SHOWERS INTO THIS
EVENING BEFORE THE MORE WIDESPREAD AND MODERATE RAINFALL MOVES
INTO THE REGION (MOSTLY AFTER MIDNIGHT). STILL LOOKING LIKE AROUND
AN INCH OF WIDESPREAD RAINFALL...WITH ISOLATED HIGHER AMOUNTS
POSSIBLE. AS THE UPPER WAVE PROPAGATES NORTHEAST ON
SATURDAY...RAINFALL WILL END FROM WEST TO EAST ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 314 PM CDT FRI SEP 27 2013
SUNDAY-MONDAY...FAST ZONAL UPPER FLOW ALONG WITH LOW LEVEL
SOUTHERLY FLOW WILL DEVELOP. THIS SHOULD LEAD TO DRY WEATHER
ALONG WITH TEMPERATURES ABOVE NORMAL. 12Z MODELS DO NOT SHOW ANY
STRONGER UPPER WAVES DURING THIS PERIOD.
MONDAY NIGHT-FRIDAY...ZONAL FLOW TO START THE EXTENDED FORECAST
PERIOD ON TUESDAY...ECMWF HINTS AT A SHORT WAVE PASSING THROUGH
THE FLOW PAINTING SOME PCPN. BUT THIS SEEMS NEW AND IS CONTRARY TO
OTHER GUIDANCE SO WILL KEEP TUESDAY DRY. 850 MB TEMPS IN THE 10 TO
15C RANGE POINT TO A WARM START TO THE WEEK WITH SOUTHERN SPOTS
MAXING OUT IN THE 70S.
ECMWF ALSO APPEARS TO BE PLACING PCPN A LITTLE TOO FAR NORTH
FOR WEDNESDAY WITH HIGH PRESSURE OVER THE REGION AND HAVE OPTED TO
CONTINUE OUR DRY FCST THROUGH MIDWEEK. SURFACE TROUGH/FRONT SHOULD
MAKE ITS WAY TO THE CWA BY THURSDAY HOWEVER...WITH INDICATIONS OF
CAPE SUITABLE FOR SOME THUNDER...TRANSITIONING TO RAIN SHOWERS BY
FRIDAY AS THE SYSTEM MOVES WELL EAST. THE MILD TEMPS OF THE FIRST
HALF OF THE WEEK WILL BE GONE BY FRIDAY...AS COLDER IS DRAWN DOWN
FROM CANADA LEE OF THE TROUGH...LEAVING THE MERCURY IN THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 637 PM CDT FRI SEP 27 2013
TAFS WILL BE AN ONGOING PROCESS THROUGH THE EVENING WITH RADICALLY
VARYING CIGS. GENERAL CIGS MVFR/VFR WITH SPATTERING OF IFR CIGS.
EXPECT CIGS TO GRADUALLY LOWER LATER THIS EVENING AS MAIN RAIN
BANDS BEGIN TO AFFECT WESTERN AND SOUTHERN AREAS THEN SPREADING
NORTHWARD AFT MIDNIGHT. VSBY NOT A REAL ISSUE AT THIS POINT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
643 PM CDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 637 PM CDT FRI SEP 27 2013
PRIMARY FOCUS THIS UPDATE WAS TO ADJUST POPS THROUGH THE EARLY TO
MID EVENING. MORE ORGANIZED -RA APPROACHING NW FA AND INCREASED
POPS THROUGH THE EVENING THIS AREA. ELSEWHERE PCPN MORE SPOTTY
WITH MAIN RAIN BAND MOVING INTO SOUTHERN FA LATER THIS EVENING.
MADE POP ADJUSTMENTS ACCORDINGLY THESE AREAS. T THREAT AT THIS POINT
LOOKS MINIMAL. NO OTHER CHANGES NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 314 PM CDT FRI SEP 27 2013
THE CHALLENGE WILL BE RAIN CHANCES AND AMOUNTS. EVERYTHING YOU
HAVE READ IN THE PAST COUPLE DAYS (SEE PREVIOUS FORECAST
DISCUSSIONS) IS STILL VALID AND THE FORECAST IS UNFOLDING
ACCORDING TO PLAN. THE 12Z NAM IS A BIT FURTHER WEST WITH THE MAIN
BAND OF RAIN TONIGHT...AND THE RAP IS ALSO WEST. WILL CONTINUE TO
FOLLOW THE MOST CONSISTENT ECMWF (WHICH MOSTLY IS IN AGREEMENT
WITH THE GFS AND GEM). THERE WILL BE AREAS OF SHOWERS INTO THIS
EVENING BEFORE THE MORE WIDESPREAD AND MODERATE RAINFALL MOVES
INTO THE REGION (MOSTLY AFTER MIDNIGHT). STILL LOOKING LIKE AROUND
AN INCH OF WIDESPREAD RAINFALL...WITH ISOLATED HIGHER AMOUNTS
POSSIBLE. AS THE UPPER WAVE PROPAGATES NORTHEAST ON
SATURDAY...RAINFALL WILL END FROM WEST TO EAST ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 314 PM CDT FRI SEP 27 2013
SUNDAY-MONDAY...FAST ZONAL UPPER FLOW ALONG WITH LOW LEVEL
SOUTHERLY FLOW WILL DEVELOP. THIS SHOULD LEAD TO DRY WEATHER
ALONG WITH TEMPERATURES ABOVE NORMAL. 12Z MODELS DO NOT SHOW ANY
STRONGER UPPER WAVES DURING THIS PERIOD.
MONDAY NIGHT-FRIDAY...ZONAL FLOW TO START THE EXTENDED FORECAST
PERIOD ON TUESDAY...ECMWF HINTS AT A SHORT WAVE PASSING THROUGH
THE FLOW PAINTING SOME PCPN. BUT THIS SEEMS NEW AND IS CONTRARY TO
OTHER GUIDANCE SO WILL KEEP TUESDAY DRY. 850 MB TEMPS IN THE 10 TO
15C RANGE POINT TO A WARM START TO THE WEEK WITH SOUTHERN SPOTS
MAXING OUT IN THE 70S.
ECMWF ALSO APPEARS TO BE PLACING PCPN A LITTLE TOO FAR NORTH
FOR WEDNESDAY WITH HIGH PRESSURE OVER THE REGION AND HAVE OPTED TO
CONTINUE OUR DRY FCST THROUGH MIDWEEK. SURFACE TROUGH/FRONT SHOULD
MAKE ITS WAY TO THE CWA BY THURSDAY HOWEVER...WITH INDICATIONS OF
CAPE SUITABLE FOR SOME THUNDER...TRANSITIONING TO RAIN SHOWERS BY
FRIDAY AS THE SYSTEM MOVES WELL EAST. THE MILD TEMPS OF THE FIRST
HALF OF THE WEEK WILL BE GONE BY FRIDAY...AS COLDER IS DRAWN DOWN
FROM CANADA LEE OF THE TROUGH...LEAVING THE MERCURY IN THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 637 PM CDT FRI SEP 27 2013
TAFS WILL BE AN ONGOING PROCESS THROUGH THE EVENING WITH RADICALLY
VARYING CIGS. GENERAL CIGS MVFR/VFR WITH SPATTERING OF IFR CIGS.
EXPECT CIGS TO GRADUALLY LOWER LATER THIS EVENING AS MAIN RAIN
BANDS BEGIN TO AFFECT WESTERN AND SOUTHERN AREAS THEN SPREADING
NORTHWARD AFT MIDNIGHT. VSBY NOT A REAL ISSUE AT THIS POINT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
101 PM CDT THU SEP 26 2013
.UPDATE...
ISSUED AT 101 PM CDT THU SEP 26 2013
GRADIENT FLOW HAS NOT RESPONDED AS PREVIOUSLY EXPECTED. THE
SURFACE LOW CONTINUES TO LIFT FARTHER NORTH INTO CANADA THAN HIGH
PRESSURE CAN BUILD INTO WESTERN NORTH DAKOTA. THEREFORE...SUSTAINED
SURFACE WINDS HAVE ONLY INCREASED TO AROUND 20 KNOTS EARLY THIS
AFTERNOON.
IN ADDITION...THE LATEST MODEL GUIDANCE CONTINUES TO BACK OFF ON
WIND SPEEDS THIS AFTERNOON AS GRADIENT FLOW IS WEAKER THAN
PREVIOUSLY EXPECTED. SUSTAINED WIND SPEEDS ARE EXPECTED TO BE UP
TO 25 MPH THIS AFTERNOON WITH 35 MPH GUSTS...WHICH IS BELOW WIND
ADVISORY CRITERIA. AS A RESULT...DECIDED TO CANCEL THE WIND
ADVISORY FOR SOUTHWESTERN INTO NORTH CENTRAL NORTH DAKOTA THIS
AFTERNOON.
ALSO REMOVED AFTERNOON CONVECTION BASED ON CURRENT RADAR
OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 949 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO LIFT
NORTH OUT OF NORTH CENTRAL NORTH DAKOTA THIS MORNING. NONE OF THIS
ACTIVITY SHOULD BE SEVERE. ALL THUNDERSTORM ACTIVITY WILL BE OUT
OF THE CWA BY THIS AFTERNOON.
HIGH PRESSURE BUILDING INTO WESTERN NORTH DAKOTA AND LOW PRESSURE
LIFTING INTO MANITOBA WILL GENERATE WINDY CONDITIONS ACROSS
WESTERN AND NORTH CENTRAL NORTH DAKOTA THIS AFTERNOON. THE LATEST
MODEL PROGS HAVE BACKED OFF ON THE SUSTAINED WIND SPEED FORECAST
THIS AFTERNOON. HOWEVER...STILL THINK MARGINAL WIND ADVISORY
CONDITIONS WILL BE ACHIEVED IN SOME SPOTS. THEREFORE...MAINTAINED
THE CURRENT TEMPORAL AND AREAL RESOLUTION OF THE WIND ADVISORY
THIS AFTERNOON.
THE REMAINING FORECAST ELEMENTS ARE ON TRACK. THE UPDATED PRODUCTS
HAVE BEEN SENT.
UPDATE ISSUED AT 651 AM CDT THU SEP 26 2013
LOW PRESSURE SITUATED OVER CENTRAL NORTH DAKOTA WITH SCATTERED
SHOWERS AND THUNDERSTORMS LIFTING FROM EAST CENTRAL INTO NORTHEAST
NORTH DAKOTA...AND SHOWERS EXTENDING BACK INTO CENTRAL NORTH
DAKOTA JUST AHEAD OF THE LOW. COLD NORTHERLY FLOW HAS MOVED INTO
WESTERN NORTH DAKOTA WITH IFR CLOUDINESS SPREADING EAST ACROSS
WESTERN NORTH DAKOTA. UPDATED WEATHER POPS TO MATCH WITH LATEST
RADAR IMAGERY...AND EXTRAPOLATING NORTHEAST THROUGH THE MORNING.
LIMITED MENTION OF THUNDER TO THE EAST CENTRAL AND FAR NORTH
CENTRAL. INCREASED SKY COVER OVER THE WEST THROUGH THE MORNING TO
ACCOUNT FOR THE LOW STRATUS. EXPECT THIS TO DISSIPATE BY LATE
MORNING AND AFTERNOON WITH STRONG SUBSIDENCE MOVING INTO WESTERN
NORTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT THU SEP 26 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORMS EARLY THIS MORNING
FOLLOWED BY A WIND ADVISORY SOUTHWEST THROUGH NORTH CENTRAL. HAVE
UTILIZED A BLEND OF ALL MODELS...BUT SPECIFICALLY THE HRRR FOR
AREAL COVERAGE OF PRECIPITATION THIS MORNING AND NAM/GFS FOR THE
WIND ADVISORY.
THE LATEST WATER VAPOR IMAGERY ALONG WITH SPC MESOSCALE ANALYSIS
CONTINUES TO SHOW THE H3 JET STREAK WORKING ITS WAY THROUGH
WYOMING AND INTO SOUTH DAKOTA. UPPER DIVERGENCE FIELD ASSOCIATED
WITH THE LEFT EXIT REGION CENTERED OVER CENTRAL/NORTHERN NORTH
DAKOTA AS ISOLATED THUNDERSTORMS CONTINUE TO ESCALATE UPWARDS.
SURFACE LOW PRESSURE IN SOUTHERN SOUTH DAKOTA WILL BEGIN TO MOVE
NORTH ALONG A COLD FRONT WHICH IS NOW LOCATED FROM NEAR OXBOW
SASKATCHEWAN...SOUTH TO MINOT AND INTO LEMMON SOUTH DAKOTA. AS THE
JET STREAK AND UPPER DIVERGENCE FIELD SHIFT FURTHER NORTH THROUGH
THE MORNING...THE SURFACE LOW WILL DEEPEN AS IT ENTERS SOUTHERN
SASKATCHEWAN THIS AFTERNOON. A TIGHT PRESSURE GRADIENT WILL
ENSUE...RESULTING IN A MARGINAL WIND ADVISORY EVENT. WITH SUSTAINED
WINDS VERY NEAR 30 MPH AND GUSTS TO 40 MPH OVER A FAIRLY LARGE
AREA...DECIDED TO ISSUE A WIND ADVISORY FOR THE SOUTHWEST AND
NORTH CENTRAL ZONES. WINDS WILL INCREASE FIRST ACROSS THE SOUTHWEST
LATE THURSDAY MORNING...THEN TRANSLATE INTO NORTH CENTRAL BEGINNING
IN THE EARLY AFTERNOON. WINDS WILL THEN DIMINISH FROM SOUTH TO
NORTH THURSDAY EVENING.
AS FAR AS SHOWERS AND THUNDERSTORMS...THERE WILL BE A DIMINISHING
EFFECT AS THE SURFACE LOW MOVES FROM SOUTH TO NORTH TODAY. MAIN
INSTABILITY WASHES OUT BY 18Z IN THE NORTH AND HAVE ENDED THE
THUNDERSTORM THREAT IN THE GRIDDED FORECAST AT THAT TIME. DRY
WEATHER COMMENCES CENTRAL AND SOUTH TODAY INTO EARLY TONIGHT. THE
NEXT ROUND OF SHOWERS BEGINS IN THE SOUTHWEST EARLY TONIGHT AND
GRADUALLY EXPANDS NORTHEAST OVERNIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 249 AM CDT THU SEP 26 2013
THE MAIN FORECAST ISSUE IN THE LONG TERM PERIOD WILL BE
PRECIPITATION CHANCES AND PLACEMENT FRIDAY THROUGH SATURDAY MORNING.
THERE IS STILL SOME DISAGREEMENT AMONG THE DETERMINISTIC MODELS WITH
PRECIPITATION ACROSS NORTH DAKOTA ON FRIDAY. HOWEVER...THERE IS MUCH
BETTER AGREEMENT FRIDAY NIGHT INTO SATURDAY MORNING.
WE BEGIN THE LONG TERM PERIOD ON FRIDAY WITH AN UPPER LEVEL TROUGH
OVER THE NORTHERN AND CENTRAL ROCKIES. SHEARED VORTICITY ALONG THE
LEADING EDGE OF THE TROUGH EXTENDS ACROSS EASTERN MONTANA AND
WESTERN NORTH DAKOTA. THE ECMWF IS SHOWING A BROAD AREA OF LIGHT TO
MODERATE RAIN LIFTING SOUTHWEST TO NORTHEAST ACROSS THE FORECAST
AREA...WHILE THE GFS/GEM CONTINUE TO INDICATE TWO SEPARATE AREAS OF
PRECIPITATION...ONE OVER THE WESTERN DAKOTAS ASSOCIATED WITH THE
UPPER LEVEL TROUGH...AND ANOTHER OVER EASTERN NORTH DAKOTA
ASSOCIATED WITH THE SURFACE SYSTEM...AND A DRY SLOT OVER CENTRAL
NORTH DAKOTA. DUE TO CONTINUED DIFFERENCES...WILL SETTLE ON A BROAD
BRUSH OF CHANCE TO HIGH CHANCE POPS UNTIL THERE IS BETTER MODEL
AGREEMENT. EITHER WAY IT WILL BE QUITE COOL AND CLOUDY WITH
SCATTERED LIGHT RAIN AND HIGHS MAINLY IN THE 50S.
THERE IS BETTER MODEL AGREEMENT AS THE KICKER SHORTWAVE ROUNDS THE
BASE OF THE UPPER TROUGH AND LIFTS INTO THE CENTRAL PLAINS FRIDAY
NIGHT. STRONG 2D FRONTOGENESIS SETS UP OVER THE EASTERN DAKOTAS
FRIDAY NIGHT AS THE SURFACE LOW TRACKS FROM THE CENTRAL PLAINS INTO
NORTHERN MINNESOTA BY SATURDAY MORNING. THIS RESULTS IN AN ENHANCED
BAND OF DEFORMATION RAIN OVER FAR SOUTH CENTRAL NORTH DAKOTA THROUGH
THE JAMES RIVER VALLEY AND INTO EASTERN NORTH DAKOTA.
THE RAIN WILL EXIT THE JAMES RIVER VALLEY SATURDAY MORNING WITH
CLEARING SKIES OVER WESTERN NORTH DAKOTA. WE WILL NEED TO MONITOR
FOR POSSIBLE FROST HIGHLIGHTS ACROSS THE WEST ON SATURDAY MORNING
WITH LOWS POSSIBLY FALLING INTO THE MID TO UPPER 30S IF SKIES
CLEAR AND WINDS SUBSIDE.
UPPER LEVEL RIDGING BUILDS OVER THE AREA THROUGH THE REMAINDER OF
THE WEEKEND WITH TEMPERATURES WARMING INTO THE 70S BY SUNDAY AND
MONDAY. A QUASI-ZONAL FLOW THEN TAKES SHAPE THROUGH MID WEEK WITH
THE STORM TRACK SITUATED NORTH OF THE BORDER. THUS MAINLY DRY
CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 101 PM CDT THU SEP 26 2013
MVFR CIGS WILL GRADUALLY IMPROVE TO VFR FROM SOUTH TO NORTH THIS
AFTERNOON. VFR CONDITIONS ARE EXPECTED TO CONTINUE OVER WESTERN
AND CENTRAL NORTH DAKOTA TONIGHT. MVFR CONDITIONS WILL SPREAD
FROM SOUTHWEST TO NORTHEAST FRIDAY MORNING AS SHOWERS DEVELOP.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...KS
LONG TERM...TWH
AVIATION...TM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1235 PM CDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1235 PM CDT THU SEP 26 2013
EXPANDED THE MOSTLY CLOUDY SKY INTO THE VALLEY THROUGH MUCH OF THE
AFTERNOON HOURS. 15Z RAP INDICATES CLEARING POSSIBLE THIS
EVENING...SO KEPT THAT IDEA. CURRENT TEMPERATURES APPEAR TO BE ON
TRACK WITH THE FORECASTED HIGHS. WINDS AND PRECIP ARE BEHAVING AS
EXPECTED.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU SEP 26 2013
THE MAIN CHALLENGE WILL BE PRECIP CHANCES FRIDAY INTO SATURDAY.
MODELS HAVE COME INTO BETTER AGREEMENT WITH NEXT SYSTEM...AND THE
POTENTIAL FOR A FAIRLY LARGE AREA TO RECEIVE AN INCH OR MORE OF
RAIN. THE GFS/ECMWF APPEARS TO BE A GOOD COMPROMISE WITH MINIMAL
DIFFERENCES WITH THE ECMWF STILL A BIT SLOWER AND SLIGHTLY FURTHER
WEST.
FOR TODAY...IT WILL BE WINDY WITH ABOUT 30KT TO MIX FROM THE
SOUTH...SHIFTING SW BY LATE AFTERNOON. THERE COULD BE A FEW HOURS
THAT ARE BORDERLINE WIND ADVISORY IN THE VALLEY...BUT FEEL WE
SHOULD REMAIN BELOW THE 30 MPH SUSTAINED THRESHOLD...BUT SOMETHING
THE DAY CREW WILL MONITOR. OTHERWISE...IT WILL BE A VERY WARM DAY
WITH SOME AREAS REACHING 80 IN THE SOUTH IN THE WARM SECTOR. THERE
COULD ALSO BE A FEW SHOWERS/STORMS THIS MORNING IN THE DEVILS LAKE
BASIN INTO THE NORTHERN VALLEY NEAR MID LEVEL WARM ADVECTION AND
SOME WEAK INSTABILITY.
FOR TONIGHT...EXPECT A DRY START WITH THE CHANCES FOR SHOWERS AND
A FEW STORMS INCREASING AFTER 06Z IN THE SOUTH AND EAST. THERE
WILL BE INCREASING DEEP LAYERED MOISTURE AND SLIGHTLY NEGATIVE
SHOWALTERS ALONG A SFC BOUNDARY...WITH A FEW STRONG STORMS IN THE
SOUTH NOT OUT OF THE QUESTION.
FOR FRIDAY...EXPECT PLENTY OF CLOUDS WITH INCREASING LIFT AS A
SHORTWAVE APPROACHES IN SW FLOW ALOFT. THERE SHOULD BE SHOWERS AND
STORMS IN THE SOUTH WITH JUST SHOWERS IN THE NORTH. TEMPS WILL BE
MUCH COOLER THAN RECENT DAYS WITH CLOUDS AND PRECIP AROUND.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU SEP 26 2013
FOR FRIDAY NIGHT INTO SATURDAY...EXPECT A STRONG SHORTWAVE TO MOVE
OVER THE SFC BOUNDARY WITH PWATS AROUND 1.5 INCHES IN THE SOUTH.
EXPECT A FAIRLY WIDESPREAD DEFORMATION RAIN BAND TO THE NORTH OF
THE SFC FRONT...WITH SOME SHOWERS AND STORMS MAINLY IN THE FAR
EASTERN AREAS. RAINFALL COULD BE HEAVY AT TIMES LATER FRIDAY NIGHT
INTO SAT MORNING AND STRONG MID LEVEL OMEGA...AND A COUPLED UPPER
LEVEL JET ENHANCE DIVERGENCE ALOFT OVER MUCH OF THE REGION. EXPECT
AREAS IN THE DEFORMATION RAIN BAND TO GET 1 TO 1.25 INCHES OF
RAINFALL WITH LOCALLY HIGHER AMOUNTS POSSIBLE. ON SATURDAY...LIGHT
RAIN SHOULD LINGER ALL DAY IN THE FAR EAST WITH A SLOW CLEARING
TREND ALONG AND WEST OF THE VALLEY BY AFTERNOON.
FOR SUNDAY TO WEDNESDAY NIGHT...NO PCPN IN THE FORECAST FOR THIS
PERIOD AS ZONAL FLOW KEEPS MOISTURE SOUTH OF THE AREA. WEAK SHORT
WAVES EMBEDDED IN THE MEAN WESTERLY FLOW WILL TRACK NORTH OF THE
AREA KEEPING THE BEST PCPN CHANCES IN CANADA MONDAY AND TUESDAY.
TEMPS TO BE AT OR ABOVE NORMAL FOR THE FIRST HALF OF THE WEEK WITH
70S SUN TO TUE AND 60S EXPECTED ON WED...STILL NO WIDESPREAD FROST
OR KILLING FREEZE ANTICIPATED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU SEP 26 2013
AVIATION FORECAST CHALLENGE WILL BE CIG HEIGHTS BEHIND APPROACHING
COLD FRONT. ARE SEEING MVFR JUST AHEAD OF WIND SHIFT
BOUNDARY...WHICH SHOULD REACH DVL IN THE NEXT COUPLE OF HOURS.
MOST OF CENTRAL AND WESTERN ND ARE REPORTING MVFR CIGS BEHIND THE
FRONT...SO WILL LOWER CIGS FOR GFK/DVL FOR LATE EVENING AND
OVERNIGHT. NOT AS CONFIDENT FAR WILL GO MVFR BECAUSE BEST LOW
LEVEL MOISTURE IS FURTHER NORTH. WINDS WILL SHIFT FROM S TO NW AT
ALL SITES EXCEPT BJI BY FRI MORNING. EXPECT MVFR CIGS TO GRADUALLY
FILL IN REMAINDER OF THE AREA ON FRIDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...DK
LONG TERM...JK/DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
949 AM CDT THU SEP 26 2013
.UPDATE...
ISSUED AT 949 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO LIFT
NORTH OUT OF NORTH CENTRAL NORTH DAKOTA THIS MORNING. NONE OF THIS
ACTIVITY SHOULD BE SEVERE. ALL THUNDERSTORM ACTIVITY WILL BE OUT
OF THE CWA BY THIS AFTERNOON.
HIGH PRESSURE BUILDING INTO WESTERN NORTH DAKOTA AND LOW PRESSURE
LIFTING INTO MANITOBA WILL GENERATE WINDY CONDITIONS ACROSS
WESTERN AND NORTH CENTRAL NORTH DAKOTA THIS AFTERNOON. THE LATEST
MODEL PROGS HAVE BACKED OFF ON THE SUSTAINED WIND SPEED FORECAST
THIS AFTERNOON. HOWEVER...STILL THINK MARGINAL WIND ADVISORY
CONDITIONS WILL BE ACHIEVED IN SOME SPOTS. THEREFORE...MAINTAINED
THE CURRENT TEMPORAL AND AREAL RESOLUTION OF THE WIND ADVISORY
THIS AFTERNOON.
THE REMAINING FORECAST ELEMENTS ARE ON TRACK. THE UPDATED PRODUCTS
HAVE BEEN SENT.
UPDATE ISSUED AT 651 AM CDT THU SEP 26 2013
LOW PRESSURE SITUATED OVER CENTRAL NORTH DAKOTA WITH SCATTERED
SHOWERS AND THUNDERSTORMS LIFTING FROM EAST CENTRAL INTO NORTHEAST
NORTH DAKOTA...AND SHOWERS EXTENDING BACK INTO CENTRAL NORTH
DAKOTA JUST AHEAD OF THE LOW. COLD NORTHERLY FLOW HAS MOVED INTO
WESTERN NORTH DAKOTA WITH IFR CLOUDINESS SPREADING EAST ACROSS
WESTERN NORTH DAKOTA. UPDATED WEATHER POPS TO MATCH WITH LATEST
RADAR IMAGERY...AND EXTRAPOLATING NORTHEAST THROUGH THE MORNING.
LIMITED MENTION OF THUNDER TO THE EAST CENTRAL AND FAR NORTH
CENTRAL. INCREASED SKY COVER OVER THE WEST THROUGH THE MORNING TO
ACCOUNT FOR THE LOW STRATUS. EXPECT THIS TO DISSIPATE BY LATE
MORNING AND AFTERNOON WITH STRONG SUBSIDENCE MOVING INTO WESTERN
NORTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT THU SEP 26 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORMS EARLY THIS MORNING
FOLLOWED BY A WIND ADVISORY SOUTHWEST THROUGH NORTH CENTRAL. HAVE
UTILIZED A BLEND OF ALL MODELS...BUT SPECIFICALLY THE HRRR FOR
AREAL COVERAGE OF PRECIPITATION THIS MORNING AND NAM/GFS FOR THE
WIND ADVISORY.
THE LATEST WATER VAPOR IMAGERY ALONG WITH SPC MESOSCALE ANALYSIS
CONTINUES TO SHOW THE H3 JET STREAK WORKING ITS WAY THROUGH
WYOMING AND INTO SOUTH DAKOTA. UPPER DIVERGENCE FIELD ASSOCIATED
WITH THE LEFT EXIT REGION CENTERED OVER CENTRAL/NORTHERN NORTH
DAKOTA AS ISOLATED THUNDERSTORMS CONTINUE TO ESCALATE UPWARDS.
SURFACE LOW PRESSURE IN SOUTHERN SOUTH DAKOTA WILL BEGIN TO MOVE
NORTH ALONG A COLD FRONT WHICH IS NOW LOCATED FROM NEAR OXBOW
SASKATCHEWAN...SOUTH TO MINOT AND INTO LEMMON SOUTH DAKOTA. AS THE
JET STREAK AND UPPER DIVERGENCE FIELD SHIFT FURTHER NORTH THROUGH
THE MORNING...THE SURFACE LOW WILL DEEPEN AS IT ENTERS SOUTHERN
SASKATCHEWAN THIS AFTERNOON. A TIGHT PRESSURE GRADIENT WILL
ENSUE...RESULTING IN A MARGINAL WIND ADVISORY EVENT. WITH SUSTAINED
WINDS VERY NEAR 30 MPH AND GUSTS TO 40 MPH OVER A FAIRLY LARGE
AREA...DECIDED TO ISSUE A WIND ADVISORY FOR THE SOUTHWEST AND
NORTH CENTRAL ZONES. WINDS WILL INCREASE FIRST ACROSS THE SOUTHWEST
LATE THURSDAY MORNING...THEN TRANSLATE INTO NORTH CENTRAL BEGINNING
IN THE EARLY AFTERNOON. WINDS WILL THEN DIMINISH FROM SOUTH TO
NORTH THURSDAY EVENING.
AS FAR AS SHOWERS AND THUNDERSTORMS...THERE WILL BE A DIMINISHING
EFFECT AS THE SURFACE LOW MOVES FROM SOUTH TO NORTH TODAY. MAIN
INSTABILITY WASHES OUT BY 18Z IN THE NORTH AND HAVE ENDED THE
THUNDERSTORM THREAT IN THE GRIDDED FORECAST AT THAT TIME. DRY
WEATHER COMMENCES CENTRAL AND SOUTH TODAY INTO EARLY TONIGHT. THE
NEXT ROUND OF SHOWERS BEGINS IN THE SOUTHWEST EARLY TONIGHT AND
GRADUALLY EXPANDS NORTHEAST OVERNIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 249 AM CDT THU SEP 26 2013
THE MAIN FORECAST ISSUE IN THE LONG TERM PERIOD WILL BE
PRECIPITATION CHANCES AND PLACEMENT FRIDAY THROUGH SATURDAY MORNING.
THERE IS STILL SOME DISAGREEMENT AMONG THE DETERMINISTIC MODELS WITH
PRECIPITATION ACROSS NORTH DAKOTA ON FRIDAY. HOWEVER...THERE IS MUCH
BETTER AGREEMENT FRIDAY NIGHT INTO SATURDAY MORNING.
WE BEGIN THE LONG TERM PERIOD ON FRIDAY WITH AN UPPER LEVEL TROUGH
OVER THE NORTHERN AND CENTRAL ROCKIES. SHEARED VORTICITY ALONG THE
LEADING EDGE OF THE TROUGH EXTENDS ACROSS EASTERN MONTANA AND
WESTERN NORTH DAKOTA. THE ECMWF IS SHOWING A BROAD AREA OF LIGHT TO
MODERATE RAIN LIFTING SOUTHWEST TO NORTHEAST ACROSS THE FORECAST
AREA...WHILE THE GFS/GEM CONTINUE TO INDICATE TWO SEPARATE AREAS OF
PRECIPITATION...ONE OVER THE WESTERN DAKOTAS ASSOCIATED WITH THE
UPPER LEVEL TROUGH...AND ANOTHER OVER EASTERN NORTH DAKOTA
ASSOCIATED WITH THE SURFACE SYSTEM...AND A DRY SLOT OVER CENTRAL
NORTH DAKOTA. DUE TO CONTINUED DIFFERENCES...WILL SETTLE ON A BROAD
BRUSH OF CHANCE TO HIGH CHANCE POPS UNTIL THERE IS BETTER MODEL
AGREEMENT. EITHER WAY IT WILL BE QUITE COOL AND CLOUDY WITH
SCATTERED LIGHT RAIN AND HIGHS MAINLY IN THE 50S.
THERE IS BETTER MODEL AGREEMENT AS THE KICKER SHORTWAVE ROUNDS THE
BASE OF THE UPPER TROUGH AND LIFTS INTO THE CENTRAL PLAINS FRIDAY
NIGHT. STRONG 2D FRONTOGENESIS SETS UP OVER THE EASTERN DAKOTAS
FRIDAY NIGHT AS THE SURFACE LOW TRACKS FROM THE CENTRAL PLAINS INTO
NORTHERN MINNESOTA BY SATURDAY MORNING. THIS RESULTS IN AN ENHANCED
BAND OF DEFORMATION RAIN OVER FAR SOUTH CENTRAL NORTH DAKOTA THROUGH
THE JAMES RIVER VALLEY AND INTO EASTERN NORTH DAKOTA.
THE RAIN WILL EXIT THE JAMES RIVER VALLEY SATURDAY MORNING WITH
CLEARING SKIES OVER WESTERN NORTH DAKOTA. WE WILL NEED TO MONITOR
FOR POSSIBLE FROST HIGHLIGHTS ACROSS THE WEST ON SATURDAY MORNING
WITH LOWS POSSIBLY FALLING INTO THE MID TO UPPER 30S IF SKIES
CLEAR AND WINDS SUBSIDE.
UPPER LEVEL RIDGING BUILDS OVER THE AREA THROUGH THE REMAINDER OF
THE WEEKEND WITH TEMPERATURES WARMING INTO THE 70S BY SUNDAY AND
MONDAY. A QUASI-ZONAL FLOW THEN TAKES SHAPE THROUGH MID WEEK WITH
THE STORM TRACK SITUATED NORTH OF THE BORDER. THUS MAINLY DRY
CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 651 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS REMAIN IN THE FORECAST
FOR KMOT WITH A VCSH AT KISN/KDIK/KBIS. KJMS WILL HAVE A VCTS
THROUGH 16Z TODAY. EXPECT IFR TO MVFR CIGS THROUGH 18Z WITH CIGS
LIFTING TO LOW VFR. GUSTY WESTERLY TO SOUTHWESTERLY WINDS WILL
DEVELOP BY LATE MORNING AT KDIK AND EARLY AFTERNOON AT KMOT. CIGS
WILL AGAIN DETERIORATE THURSDAY NIGHT AS SHOWERS DEVELOP IN THE
SOUTHWEST AND SPREAD NORTHEAST THROUGH 12Z FRIDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NDZ018-
019-021-031>033-040-041-043-044.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM CDT THIS EVENING
FOR NDZ002>004-010>012.
&&
$$
UPDATE...TM
SHORT TERM...KS
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
651 AM CDT THU SEP 26 2013
.UPDATE...
ISSUED AT 651 AM CDT THU SEP 26 2013
LOW PRESSURE SITUATED OVER CENTRAL NORTH DAKOTA WITH SCATTERED
SHOWERS AND THUNDERSTORMS LIFTING FROM EAST CENTRAL INTO NORTHEAST
NORTH DAKOTA...AND SHOWERS EXTENDING BACK INTO CENTRAL NORTH
DAKOTA JUST AHEAD OF THE LOW. COLD NORTHERLY FLOW HAS MOVED INTO
WESTERN NORTH DAKOTA WITH IFR CLOUDINESS SPREADING EAST ACROSS
WESTERN NORTH DAKOTA. UPDATED WEATHER POPS TO MATCH WITH LATEST
RADAR IMAGERY...AND EXTRAPOLATING NORTHEAST THROUGH THE MORNING.
LIMITED MENTION OF THUNDER TO THE EAST CENTRAL AND FAR NORTH
CENTRAL. INCREASED SKY COVER OVER THE WEST THROUGH THE MORNING TO
ACCOUNT FOR THE LOW STRATUS. EXPECT THIS TO DISSIPATE BY LATE
MORNING AND AFTERNOON WITH STRONG SUBSIDENCE MOVING INTO WESTERN
NORTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT THU SEP 26 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORMS EARLY THIS MORNING
FOLLOWED BY A WIND ADVISORY SOUTHWEST THROUGH NORTH CENTRAL. HAVE
UTILIZED A BLEND OF ALL MODELS...BUT SPECIFICALLY THE HRRR FOR
AREAL COVERAGE OF PRECIPITATION THIS MORNING AND NAM/GFS FOR THE
WIND ADVISORY.
THE LATEST WATER VAPOR IMAGERY ALONG WITH SPC MESOSCALE ANALYSIS
CONTINUES TO SHOW THE H3 JET STREAK WORKING ITS WAY THROUGH
WYOMING AND INTO SOUTH DAKOTA. UPPER DIVERGENCE FIELD ASSOCIATED
WITH THE LEFT EXIT REGION CENTERED OVER CENTRAL/NORTHERN NORTH
DAKOTA AS ISOLATED THUNDERSTORMS CONTINUE TO ESCALATE UPWARDS.
SURFACE LOW PRESSURE IN SOUTHERN SOUTH DAKOTA WILL BEGIN TO MOVE
NORTH ALONG A COLD FRONT WHICH IS NOW LOCATED FROM NEAR OXBOW
SASKATCHEWAN...SOUTH TO MINOT AND INTO LEMMON SOUTH DAKOTA. AS THE
JET STREAK AND UPPER DIVERGENCE FIELD SHIFT FURTHER NORTH THROUGH
THE MORNING...THE SURFACE LOW WILL DEEPEN AS IT ENTERS SOUTHERN
SASKATCHEWAN THIS AFTERNOON. A TIGHT PRESSURE GRADIENT WILL
ENSUE...RESULTING IN A MARGINAL WIND ADVISORY EVENT. WITH SUSTAINED
WINDS VERY NEAR 30 MPH AND GUSTS TO 40 MPH OVER A FAIRLY LARGE
AREA...DECIDED TO ISSUE A WIND ADVISORY FOR THE SOUTHWEST AND
NORTH CENTRAL ZONES. WINDS WILL INCREASE FIRST ACROSS THE SOUTHWEST
LATE THURSDAY MORNING...THEN TRANSLATE INTO NORTH CENTRAL BEGINNING
IN THE EARLY AFTERNOON. WINDS WILL THEN DIMINISH FROM SOUTH TO
NORTH THURSDAY EVENING.
AS FAR AS SHOWERS AND THUNDERSTORMS...THERE WILL BE A DIMINISHING
EFFECT AS THE SURFACE LOW MOVES FROM SOUTH TO NORTH TODAY. MAIN
INSTABILITY WASHES OUT BY 18Z IN THE NORTH AND HAVE ENDED THE
THUNDERSTORM THREAT IN THE GRIDDED FORECAST AT THAT TIME. DRY
WEATHER COMMENCES CENTRAL AND SOUTH TODAY INTO EARLY TONIGHT. THE
NEXT ROUND OF SHOWERS BEGINS IN THE SOUTHWEST EARLY TONIGHT AND
GRADUALLY EXPANDS NORTHEAST OVERNIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 249 AM CDT THU SEP 26 2013
THE MAIN FORECAST ISSUE IN THE LONG TERM PERIOD WILL BE
PRECIPITATION CHANCES AND PLACEMENT FRIDAY THROUGH SATURDAY MORNING.
THERE IS STILL SOME DISAGREEMENT AMONG THE DETERMINISTIC MODELS WITH
PRECIPITATION ACROSS NORTH DAKOTA ON FRIDAY. HOWEVER...THERE IS MUCH
BETTER AGREEMENT FRIDAY NIGHT INTO SATURDAY MORNING.
WE BEGIN THE LONG TERM PERIOD ON FRIDAY WITH AN UPPER LEVEL TROUGH
OVER THE NORTHERN AND CENTRAL ROCKIES. SHEARED VORTICITY ALONG THE
LEADING EDGE OF THE TROUGH EXTENDS ACROSS EASTERN MONTANA AND
WESTERN NORTH DAKOTA. THE ECMWF IS SHOWING A BROAD AREA OF LIGHT TO
MODERATE RAIN LIFTING SOUTHWEST TO NORTHEAST ACROSS THE FORECAST
AREA...WHILE THE GFS/GEM CONTINUE TO INDICATE TWO SEPARATE AREAS OF
PRECIPITATION...ONE OVER THE WESTERN DAKOTAS ASSOCIATED WITH THE
UPPER LEVEL TROUGH...AND ANOTHER OVER EASTERN NORTH DAKOTA
ASSOCIATED WITH THE SURFACE SYSTEM...AND A DRY SLOT OVER CENTRAL
NORTH DAKOTA. DUE TO CONTINUED DIFFERENCES...WILL SETTLE ON A BROAD
BRUSH OF CHANCE TO HIGH CHANCE POPS UNTIL THERE IS BETTER MODEL
AGREEMENT. EITHER WAY IT WILL BE QUITE COOL AND CLOUDY WITH
SCATTERED LIGHT RAIN AND HIGHS MAINLY IN THE 50S.
THERE IS BETTER MODEL AGREEMENT AS THE KICKER SHORTWAVE ROUNDS THE
BASE OF THE UPPER TROUGH AND LIFTS INTO THE CENTRAL PLAINS FRIDAY
NIGHT. STRONG 2D FRONTOGENESIS SETS UP OVER THE EASTERN DAKOTAS
FRIDAY NIGHT AS THE SURFACE LOW TRACKS FROM THE CENTRAL PLAINS INTO
NORTHERN MINNESOTA BY SATURDAY MORNING. THIS RESULTS IN AN ENHANCED
BAND OF DEFORMATION RAIN OVER FAR SOUTH CENTRAL NORTH DAKOTA THROUGH
THE JAMES RIVER VALLEY AND INTO EASTERN NORTH DAKOTA.
THE RAIN WILL EXIT THE JAMES RIVER VALLEY SATURDAY MORNING WITH
CLEARING SKIES OVER WESTERN NORTH DAKOTA. WE WILL NEED TO MONITOR
FOR POSSIBLE FROST HIGHLIGHTS ACROSS THE WEST ON SATURDAY MORNING
WITH LOWS POSSIBLY FALLING INTO THE MID TO UPPER 30S IF SKIES
CLEAR AND WINDS SUBSIDE.
UPPER LEVEL RIDGING BUILDS OVER THE AREA THROUGH THE REMAINDER OF
THE WEEKEND WITH TEMPERATURES WARMING INTO THE 70S BY SUNDAY AND
MONDAY. A QUASI-ZONAL FLOW THEN TAKES SHAPE THROUGH MID WEEK WITH
THE STORM TRACK SITUATED NORTH OF THE BORDER. THUS MAINLY DRY
CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 651 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS REMAIN IN THE FORECAST
FOR KMOT WITH A VCSH AT KISN/KDIK/KBIS. KJMS WILL HAVE A VCTS
THROUGH 16Z TODAY. EXPECT IFR TO MVFR CIGS THROUGH 18Z WITH CIGS
LIFTING TO LOW VFR. GUSTY WESTERLY TO SOUTHWESTERLY WINDS WILL
DEVELOP BY LATE MORNING AT KDIK AND EARLY AFTERNOON AT KMOT. CIGS
WILL AGAIN DETERIORATE THURSDAY NIGHT AS SHOWERS DEVELOP IN THE
SOUTHWEST AND SPREAD NORTHEAST THROUGH 12Z FRIDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CDT /11 AM MDT/ TODAY TO 7 PM CDT /6 PM
MDT/ THIS EVENING FOR NDZ018-019-021-031>033-040-041-043-044.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM CDT THIS EVENING
FOR NDZ002>004-010>012.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
249 AM CDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT THU SEP 26 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORMS EARLY THIS MORNING
FOLLOWED BY A WIND ADVISORY SOUTHWEST THROUGH NORTH CENTRAL. HAVE
UTILIZED A BLEND OF ALL MODELS...BUT SPECIFICALLY THE HRRR FOR
AREAL COVERAGE OF PRECIPITATION THIS MORNING AND NAM/GFS FOR THE
WIND ADVISORY.
THE LATEST WATER VAPOR IMAGERY ALONG WITH SPC MESOSCALE ANALYSIS
CONTINUES TO SHOW THE H3 JET STREAK WORKING ITS WAY THROUGH
WYOMING AND INTO SOUTH DAKOTA. UPPER DIVERGENCE FIELD ASSOCIATED
WITH THE LEFT EXIT REGION CENTERED OVER CENTRAL/NORTHERN NORTH
DAKOTA AS ISOLATED THUNDERSTORMS CONTINUE TO ESCALATE UPWARDS.
SURFACE LOW PRESSURE IN SOUTHERN SOUTH DAKOTA WILL BEGIN TO MOVE
NORTH ALONG A COLD FRONT WHICH IS NOW LOCATED FROM NEAR OXBOW
SASKATCHEWAN...SOUTH TO MINOT AND INTO LEMMON SOUTH DAKOTA. AS THE
JET STREAK AND UPPER DIVERGENCE FIELD SHIFT FURTHER NORTH THROUGH
THE MORNING...THE SURFACE LOW WILL DEEPEN AS IT ENTERS SOUTHERN
SASKATCHEWAN THIS AFTERNOON. A TIGHT PRESSURE GRADIENT WILL
ENSUE...RESULTING IN A MARGINAL WIND ADVISORY EVENT. WITH SUSTAINED
WINDS VERY NEAR 30 MPH AND GUSTS TO 40 MPH OVER A FAIRLY LARGE
AREA...DECIDED TO ISSUE A WIND ADVISORY FOR THE SOUTHWEST AND
NORTH CENTRAL ZONES. WINDS WILL INCREASE FIRST ACROSS THE SOUTHWEST
LATE THURSDAY MORNING...THEN TRANSLATE INTO NORTH CENTRAL BEGINNING
IN THE EARLY AFTERNOON. WINDS WILL THEN DIMINISH FROM SOUTH TO
NORTH THURSDAY EVENING.
AS FAR AS SHOWERS AND THUNDERSTORMS...THERE WILL BE A DIMINISHING
EFFECT AS THE SURFACE LOW MOVES FROM SOUTH TO NORTH TODAY. MAIN
INSTABILITY WASHES OUT BY 18Z IN THE NORTH AND HAVE ENDED THE
THUNDERSTORM THREAT IN THE GRIDDED FORECAST AT THAT TIME. DRY
WEATHER COMMENCES CENTRAL AND SOUTH TODAY INTO EARLY TONIGHT. THE
NEXT ROUND OF SHOWERS BEGINS IN THE SOUTHWEST EARLY TONIGHT AND
GRADUALLY EXPANDS NORTHEAST OVERNIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 249 AM CDT THU SEP 26 2013
THE MAIN FORECAST ISSUE IN THE LONG TERM PERIOD WILL BE
PRECIPITATION CHANCES AND PLACEMENT FRIDAY THROUGH SATURDAY MORNING.
THERE IS STILL SOME DISAGREEMENT AMONG THE DETERMINISTIC MODELS WITH
PRECIPITATION ACROSS NORTH DAKOTA ON FRIDAY. HOWEVER...THERE IS MUCH
BETTER AGREEMENT FRIDAY NIGHT INTO SATURDAY MORNING.
WE BEGIN THE LONG TERM PERIOD ON FRIDAY WITH AN UPPER LEVEL TROUGH
OVER THE NORTHERN AND CENTRAL ROCKIES. SHEARED VORTICITY ALONG THE
LEADING EDGE OF THE TROUGH EXTENDS ACROSS EASTERN MONTANA AND
WESTERN NORTH DAKOTA. THE ECMWF IS SHOWING A BROAD AREA OF LIGHT TO
MODERATE RAIN LIFTING SOUTHWEST TO NORTHEAST ACROSS THE FORECAST
AREA...WHILE THE GFS/GEM CONTINUE TO INDICATE TWO SEPARATE AREAS OF
PRECIPITATION...ONE OVER THE WESTERN DAKOTAS ASSOCIATED WITH THE
UPPER LEVEL TROUGH...AND ANOTHER OVER EASTERN NORTH DAKOTA
ASSOCIATED WITH THE SURFACE SYSTEM...AND A DRY SLOT OVER CENTRAL
NORTH DAKOTA. DUE TO CONTINUED DIFFERENCES...WILL SETTLE ON A BROAD
BRUSH OF CHANCE TO HIGH CHANCE POPS UNTIL THERE IS BETTER MODEL
AGREEMENT. EITHER WAY IT WILL BE QUITE COOL AND CLOUDY WITH
SCATTERED LIGHT RAIN AND HIGHS MAINLY IN THE 50S.
THERE IS BETTER MODEL AGREEMENT AS THE KICKER SHORTWAVE ROUNDS THE
BASE OF THE UPPER TROUGH AND LIFTS INTO THE CENTRAL PLAINS FRIDAY
NIGHT. STRONG 2D FRONTOGENESIS SETS UP OVER THE EASTERN DAKOTAS
FRIDAY NIGHT AS THE SURFACE LOW TRACKS FROM THE CENTRAL PLAINS INTO
NORTHERN MINNESOTA BY SATURDAY MORNING. THIS RESULTS IN AN ENHANCED
BAND OF DEFORMATION RAIN OVER FAR SOUTH CENTRAL NORTH DAKOTA THROUGH
THE JAMES RIVER VALLEY AND INTO EASTERN NORTH DAKOTA.
THE RAIN WILL EXIT THE JAMES RIVER VALLEY SATURDAY MORNING WITH
CLEARING SKIES OVER WESTERN NORTH DAKOTA. WE WILL NEED TO MONITOR
FOR POSSIBLE FROST HIGHLIGHTS ACROSS THE WEST ON SATURDAY MORNING
WITH LOWS POSSIBLY FALLING INTO THE MID TO UPPER 30S IF SKIES
CLEAR AND WINDS SUBSIDE.
UPPER LEVEL RIDGING BUILDS OVER THE AREA THROUGH THE REMAINDER OF
THE WEEKEND WITH TEMPERATURES WARMING INTO THE 70S BY SUNDAY AND
MONDAY. A QUASI-ZONAL FLOW THEN TAKES SHAPE THROUGH MID WEEK WITH
THE STORM TRACK SITUATED NORTH OF THE BORDER. THUS MAINLY DRY
CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1206 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVERNIGHT FOR ALL
AERODROMES EXCEPT KJMS. A COLD FRONT JUST WEST OF KMOT AND KBIS
WILL SLOWLY MOVE EAST THURSDAY. A PERIOD OF MVFR CIGS TOWARD 10Z AND
12Z THURSDAY ARE FORECAST TO DEVELOP...WITH KJMS BARELY REMAINING IN
THE LOW VFR RANGE. GUSTY SOUTHWEST TO WESTERLY WINDS ARE FORECAST
THURSDAY...BETWEEN 20KT AND 32KT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CDT /11 AM MDT/ TODAY TO 7 PM CDT /6 PM
MDT/ THIS EVENING FOR NDZ018-019-021-031>033-040-041-043-044.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM CDT THIS EVENING
FOR NDZ002>004-010>012.
&&
$$
SHORT TERM...KS
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1206 AM CDT THU SEP 26 2013
.UPDATE...
ISSUED AT 1206 AM CDT THU SEP 26 2013
THE LATEST WATER VAPOR LOOP AND SPC MESOANALYSIS SHOW A H3 120KT
JET PUNCHING INTO CENTRAL AND EASTERN WYOMING WITH A DIVERGENCE
ALOFT FIELD CENTERED OVER WESTERN NORTH DAKOTA ASSOCIATED WITH THE
LEFT EXIT REGION. SURFACE COLD FRONT SLICING NORTH TO SOUTH...FROM
NEAR KENMARE SOUTH TO HAZEN AND INTO LEMMON SOUTH DAKOTA. LOW
PRESSURE WAS ANALYZED OVER SOUTHWESTERN SOUTH DAKOTA WITH 3HR
PRESSURE FALLS NON-EXISTENT ACROSS NORTH DAKOTA SUGGESTING
CONVECTION CURRENTLY IN THE WEST IS ELEVATED ABOVE THE SURFACE.
THUS FAR THE THUNDERSTORMS HAVE REMAINED BELOW SEVERE LIMITS. PEAK
WINDS HAVE BEEN 34 MPH NEAR RAY. MARGINAL MID LEVEL LAPSE RATES
WITH THE STRONGEST DOWNDRAFT CAPE DISPLACED FROM THE MAIN AREA OF
CONVECTION AS THE AXIS IS IN CENTRAL NORTH DAKOTA. WILL MAINTAIN A
MENTION OF SEVERE OVERNIGHT AS THE SURFACE LOW CONTINUES TO LIFT
NORTH AND SOME HIGHER REFLECTIVITY`S NOW EMERGING OVER WESTERN
SOUTH DAKOTA. EXPANDED POPS FURTHER NORTH AND EAST PER LATEST HRRR.
UPDATE ISSUED AT 1013 PM CDT WED SEP 25 2013
LATE EVENING UPDATE MAINLY FOR POPS BASED ON CURRENT RADAR TRENDS.
THUNDERSTORMS HAVE OVERSPREAD MUCH OF WESTERN NORTH DAKOTA. THUS
FAR...STORMS HAVE REMAINED NON-SEVERE. CANNOT RULE OUT AN ISOLATED
SEVERE STORM OVERNIGHT...MAINLY IN THE FORM OF WIND AS POTENTIAL
EXISTS FOR STRONG FLOW ALOFT TO BE TRANSPORTED TO THE LOW LEVELS BRIEFLY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 335 PM CDT WED SEP 25 2013
THE PRIMARY FORECAST CHALLENGE CONTINUES TO BE THE SEVERE WEATHER
CHANCES ACROSS WESTERN AND NORTH CENTRAL NORTH DAKOTA TONIGHT.
SHORT RANGE MODEL GUIDANCE CONTINUES TO PROG A SHORTWAVE TO LIFT
NORTH ACROSS EASTERN MONTANA AND NORTHWESTERN NORTH DAKOTA
TONIGHT. ITS ATTENDANT SURFACE TROUGH AXIS WILL TIGHTEN UP ACROSS
WESTERN NORTH DAKOTA THIS EVENING AS A RESULT. FURTHERMORE...MODEL
MUCAPE VALUES ARE FORECAST TO RANGE BETWEEN 200-400 J/KG WHILE
DEEP LAYER SHEAR WILL BE UP TO 50 KNOTS. EVEN THOUGH INSTABILITY
IS NOT TERRIBLY IMPRESSIVE...THE COMBINATION OF LOW-LEVEL MOISTURE
CONVERGENCE AND HIGH SHEAR ENVIRONMENT WILL LIKELY BE ENOUGH TO
GENERATE SEVERE THUNDERSTORMS THIS EVENING.
THE LATEST 4KM WRF-NMM AND 3KM HRRR PROG AN MCS TO DEVELOP OVER
SOUTHEASTERN MONTANA AROUND 01Z. THIS COMPLEX IS THEN PROGGED TO
LIFT NORTH ACROSS WESTERN NORTH DAKOTA THIS EVENING. THE HI-RES
MODELS ARE HINTING AT THE MCS MORPHING INTO AN MCV BY THE END OF
ITS CYCLE...GENERATING MORE OF A WIND THREAT. HOWEVER...IF
UPDRAFTS GET STRONG ENOUGH...LARGE HAIL CANNOT BE RULED OUT.
CONTINUED TO INDICATE LARGE HAIL AND DAMAGING WINDS IN THE
AFFECTED ZONES FOR TONIGHT.
PRECIP CHANCES WILL TAPER OFF FROM SOUTH TO NORTH AS THE PARENT
SHORTWAVE LIFTS INTO CANADA THURSDAY MORNING. DRY CONDITIONS ARE
THEN EXPECTED OVER MOST OF THE CWA (SANS NORTHWESTERN NORTH
DAKOTA) BY THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT WED SEP 25 2013
THE HIGHLIGHTS OF THE EXTENDED PERIOD ARE RAIN AND WIND THURSDAY
THROUGH FRIDAY NIGHT.
WIDESPREAD RAINFALL UP TO ONE INCH IS LIKELY FOR SOME PARTS OF NORTH
DAKOTA THURSDAY MORNING THROUGH FRIDAY NIGHT. GUSTY WINDS AROUND 35
MPH ARE LIKELY ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA
THURSDAY AFTERNOON.
STRONG FORCING AND AMPLE MOISTURE WILL LIKELY BE IN PLACE ACROSS THE
REGION THURSDAY THROUGH FRIDAY THANKS TO A STRONG UPPER LEVEL
JET...DEEP LONGWAVE TROUGH...AND ISALLOBARIC FORCING ALONG THE
INVERTED TROUGH. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS SHOULD EJECT
OUT OF THE MAIN LONGWAVE TROUGH TO THE WEST. IT APPEARS ONE SHOULD
ARRIVE ON OUR DOORSTEP WEDNESDAY NIGHT...THURSDAY NIGHT AND FRIDAY
NIGHT. THIS WOULD TEND TO FAVOR PRECIPITATION ARRIVING IN WAVES WITH
BREAKS IN BETWEEN.
THERE IS SOME UNCERTAINTY BETWEEN THE MAJOR MODELS AS TO
EXACT LOCATION OF THE HEAVIEST RAIN AND TIMING OF THE MAIN COLD
FRONT PUSH OUT OF THE REGION. THE 12 UTC GFS AND 12 UTC ECMWF APPEAR
TO BE SLIGHTLY SLOWER WITH THE EXIT OF THE SYSTEM AND THEREFORE
PRODUCE MORE PRECIP OVER WESTERN AND CENTRAL NORTH DAKOTA. THE 12
UTC GEM/NAM AND 09Z SREF HAVE THE BULK OF THE RAIN FALLING ACROSS
EASTERN NORTH DAKOTA WITH THE FRONT PUSHING THROUGH EARLIER FRIDAY.
THEREFORE...FOR THIS FORECAST ISSUANCE WENT WITH A BLEND OF THE
MAJOR MODELS WITH A SLIGHT FAVOR TOWARD THE EASTWARD (FASTER) MODELS
AS THE GFS HAS SHOWN A SLIGHT EASTWARD TREND OVER THE PAST FEW RUNS.
DUE TO UNCERTAINTY DID NOT INCREASE CHANCES OF PRECIPITATION FOR
THURSDAY OR FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1206 AM CDT THU SEP 26 2013
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVERNIGHT FOR ALL
AERODROMES EXCEPT KJMS. A COLD FRONT JUST WEST OF KMOT AND KBIS
WILL SLOWLY MOVE EAST THURSDAY. A PERIOD OF MVFR CIGS TOWARD 10Z AND
12Z THURSDAY ARE FORECAST TO DEVELOP...WITH KJMS BARELY REMAINING IN
THE LOW VFR RANGE. GUSTY SOUTHWEST TO WESTERLY WINDS ARE FORECAST
THURSDAY...BETWEEN 20KT AND 32KT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TM
LONG TERM...AJ
AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
ISSUED BY NATIONAL WEATHER SERVICE PITTSBURGH PA
1230 PM EDT THU SEP 26 2013
.SYNOPSIS...
HIGH PRESSURE BUILDS IN THIS AFTERNOON...REMAINING THROUGH MUCH
OF THE WEEKEND. A WEAK COLD FRONT CROSSES EARLY NEXT WEEK THEN A
RETURN TO DRY WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW CLOUDS CONTINUING TO ERODE ACR THE SRN COAL FIELDS OF WV. THEY
SHOULD BE ALL BONE BY 1730Z. DIURNAL CU IN THE MTNS...OTHERWISE NO
OTHER CHANGES TO THE ONGOING FORECAST OUTSIDE UPDATING CURRENT SKY
GRIDS. PREVIOUS DISCUSSION FOLLOWS:
H5 CYCLONE BECOMES AN OPEN WAVE TODAY AND MOVES EAST OF THE BLUE
RIDGE. MORNING FOG E OF THE OHIO RIVER ACROSS THE MTN STATE OF WV
INTO THE SWRN VA COAL FIELDS WILL DISSIPATE BY 15Z. THIS COINCIDES
WIT THE LATEST HRRR TOTAL CLOUD COVER OUTPUT. WILL BE WATCHING
POSSIBLE ADVECTION OF STRATUS ACROSS EASTERN POCAHONTAS COUNTY
DURING THE PREDAWN HOURS BASED ON LATEST H9-H8 RH TRENDS WITH ERLY
FLOW. OTHERWISE BUILDING MID LVL HEIGHTS OWE TO A WARMER AFTN.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
MODELS IN GENERAL AGREEMENT WITH UPPER RIDGE SLOWLY MOVING EASTWARD
THROUGH THE PERIOD. AS IT DOES A WEAK COOL FRONT WILL APPROACH THE
CWA FROM THE WEST AND ARRIVE LATE SUNDAY. WE WILL HAVE MOSTLY SUNNY
WARM DAYS AND RELATIVELY COOL EVENINGS WITH FOG DEVELOPING AT LEAST
FRIDAY MORNING AND TO A LESSER EXTENT AGAIN ON SATURDAY MORNING.
THE MAIN EFFECT FROM THE FRONT WILL BE AN INCREASE IN CLOUDS
SATURDAY NIGHT AS MOISTURE INCREASES FROM THE SOUTH. ON SUNDAY
LOOK FOR CLOUDS TO CONTINUE TO INCREASE AND THE CHANCE OF SHOWERS
TO INCREASE AS WELL FROM THE WEST. TEMPERATURES ARE A BLEND OF
CONSENSUS GUIDANCE AND CURRENT GRID TEMPS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THIS PERIOD WILL BE DOMINATED BY A WEAKENING COOL FRONT THAT WILL
MOVE EASTWARD ACROSS THE AREA SUNDAY NIGHT AND MONDAY MORNING.
SUPPORTING UPPER TROUGH FLATTENS OUT AS IT APPROACHES...WITH MUCH OF
THE ENERGY GOING INTO FLATTENING THE UPPER RIDGE. STILL...ENOUGH
MOISTURE RETURN AND UPPER SUPPORT TO SUPPORT SCATTERED SHOWERS WITH
THE FRONT. OTHERWISE...WITH A PROGRESSIVE WEST TO NORTHWEST UPPER
FLOW...FRONT MOVES OUT BY MONDAY EVENING WITH HIGH PRESSURE TAKING
CHARGE INTO THE MIDDLE OF NEXT WEEK. ONLY SLIGHT COOLING BEHIND THE
FRONT WITH LOTS OF SUNSHINE TUESDAY AND WEDNESDAY HELPING TO BOOST
TEMPERATURES BACK INTO THE 70S. HOWEVER...MONDAY NIGHT THROUGH
WEDNESDAY NIGHT WILL COOL BE DUE TO CLEAR SKIES AND DRY AIR.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
UPPER LEVEL SYSTEM WILL MOVE EASTWARD EARLY THIS MORNING. DENSE FOG
WILL BE SLOW TO LIFT. A CUMULUS DECK WILL THEN FORM OVER
SOUTHERN AND EASTERN PORTIONS OF THE AREA TODAY...POSSIBLY BEGINNING
AS MVFR. DENSE RIVER VALLEY FOG CAN BE EXPECTED TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM THIS MORNING...HIGH THIS AFTERNOON AND
TONIGHT.
ALTERNATE SCENARIOS: TIMING OF FOG LIFTING THIS MORNING AND FORMING
TONIGHT COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
AFTER 18Z FRIDAY...
DENSE RIVER VALLEY FOG FRIDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1018 PM EDT FRI SEP 27 2013
.SYNOPSIS...
DRY HIGH PRESSURE WILL CONTINUE TO SETTLE OVER THE REGION TONIGHT
AND LINGER INTO SUNDAY. A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE
NORTHWEST SUNDAY NIGHT INTO MONDAY BEFORE DISSIPATING OVER THE
REGION BY TUESDAY. WEAK HIGH PRESSURE WILL THEN RETURN IN ITS WAKE.
&&
.NEAR TERM /THROUGH SATURDAY/...
1000 PM UPDATE...STRATOCU IN THE MTNS/FOOTHILLS A BIT MORE
WIDESPREAD THAN ANTICIPATED...BUT SEEMS TO BE FAIRLY WELL HANDLED BY
18Z NAM AND RECENT RAP RUNS. THESE MODELS...IN PARTICULAR THE
NAM...HOLD ON TO THE CLOUD COVER UNTIL EARLY MORNING WHEN 850MB RH
VALUES DECREASE AND SUBSIDENCE STRENGTHENS AS COASTAL SFC HIGH
CONTINUES TO BUILD. THUS UPPED SKY COVER TO PCLDY-MCLDY ALONG THE
BLUE RIDGE AND INTO THE SC/GA FOOTHILLS...ALLOWING THE COVERAGE TO
TREND DOWNWARD AGAIN IN THE EARLY MRNG. REVISED TEMP TRENDS AS WELL
IN THE MORE CLOUDY AREA...AS OBS SUGGEST COOLING HAS SLOWED
ACCORDINGLY THERE. HOWEVER ANY AREAS THAT CLEAR OUT AGAIN SHOULD
QUICKLY SEE TEMPS DROP WITH DEWPOINTS WELL BELOW CURRENT READINGS AT
MOST SITES.
700 PM UPDATE...FCST REMAINS ON TRACK THOUGH WILL TOUCH UP SKY AND
TEMPS PER OBS. SEEING SOME MOISTURE IN 925-850MB LAYER ON 18Z MODELS
FOR MUCH OF THE OVERNIGHT AS WAS NOTED LAST NIGHT. WITH CONTINUED NE
WINDS...I EXPECT SOME LINGERING PATCHES OF STRATOCU NEAR THE BLUE
RIDGE THRU THE EVENING ONCE AGAIN. GUIDANCE CONTINUES TO FOCUS FOG
IN THE MTNS. WITH CONDITIONS BEING SLIGHTLY MORE BREEZY THAN LAST
NIGHT AS WELL AS SOILS HAVING HAD ANOTHER DAY TO DRY OUT...WILL BE
CONSERVATIVE WITH FOG MENTION AND ONCE AGAIN ADVERTISE IT ONLY IN
THE MTNS.
AT 230 PM EDT FRIDAY...A HIGH AMPLITUDE UPPER RIDGE WILL SLOWLY
PROGRESS ACROSS THE GREAT LAKES AND GULF STATES TONIGHT AND
SATURDAY...WHILE AN UPPER LOW CLOSES OFF EAST OF THE NC OUTER BANKS.
SURFACE HIGH PRESSURE WILL REMAIN ALONG THE EAST COAST...WHILE A
SURFACE LOW DEEPENS OFFSHORE...RESULTING IN A TIGHTENING PRESSURE
GRADIENT AND GUSTY NE WINDS ON SATURDAY. LOW LEVEL MOISTURE WILL
PERSIST EAST OF THE APPALACHIANS UNDER A SUBSIDENCE INVERSION...
RESULTING IN SCATTERED CUMULUS...MAINLY DURING DAYTIME HEATING. WARM
MID LEVEL TEMPERATURES AND LIMITED INSTABILITY WILL KEEP CONVECTION
FROM DEVELOPING. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL IN A
COOL NE FLOW.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 140 PM EDT FRI...AN APPROACHING SHORT WAVE TROUGH WILL WEAKEN
THE ERN CONUS RIDGE SATURDAY NIGHT AND SUNDAY. THE TROUGH ITSELF
WILL ALSO WEAKEN...TO THE POINT THAT THE MODELS ARE ONLY PRODUCING A
FEW SHOWERS OVER THE NC MTNS SUNDAY NIGHT. THE BALANCE OF THE DAY
SUNDAY WILL BE NICE AS THE SFC RIDGE WEAKENS BRINGING LIGHT AND
VARIABLE WINDS AND PARTLY CLOUDY SKIES. ON MONDAY A WEAKER TROUGH
WILL DIG ACROSS THE SRN APPALACHIANS. DEWPOINTS WILL INCREASE AND
LAPSE RATES WILL STEEPEN A LITTLE ON MONDAY. WITH AFTERNOON HEATING
A FEW TO SCATTERED SHRA AND TSTMS MAY FIRE OVER THE HIGH TERRAIN.
WENT WITH A 25-30 POP OVER THE NC MTNS TO ACCOUNT FOR THIS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 1 PM FRIDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON TUESDAY
WITH THE UPPER TROF LIFTING NORTHEASTWARD AND MERGING WITH THE
NORTHERN STREAM UPPER FLOW. HEIGHTS THEN BEGIN TO RISE AS THE MODELS
ARE BECOMING MORE BULLISH WITH ANOTHER UPPER RIDGE BUILDING OVER THE
SE CONUS. THIS IS IN CONTRAST WITH PREVIOUS RUNS THAT TENDED TO
FLATTEN OUT THE UPPER PATTERN AND THEN GRADUALLY BUILD THE RIDGE.
AT THE SFC...WHATS LEFT OF THE WEAK COLD FRONT SHOULD BE DISSIPATING
AS WEAK HIGH PRESSURE BUILDS BACK OVER THE REGION ON TUES AND
LINGERS THROUGH THE REMAINDER OF THE FCST PERIOD. LOW LVL WINDS WILL
LIKELY BE WEAK WITH A SLY BIAS THRU THE PERIOD. THE MODELS DIFFER ON
THE AMOUNT AND EXTENT OF DEEPER LAYER MOISTURE OVER THE FCST AREA
WITH THE ECMWF MAINTAINING MORE MOISTURE TO OUR SOUTH AND WEST THRU
MOST OF THE PERIOD. I DID NOT MAKE ANY SIGNIFICANT CHANGES TO THE
SENSIBLE FCST WITH MOSTLY DIURNAL SLIGHT CHANCE TO BRIEF SOLID
CHANCE POPS EACH DAY WITH THE SOLID CHANCE VALUES CONFINED TO THE
SOUTHERN AND WESTERN NC MTS. THESE VALUES MAY PROVE TOO HIGH IF THE
MODELS TREND AWAY FROM MORE MOIST SLY FLOW. HIGHS SHOULD START OUT
RIGHT AROUND CLIMATOLOGY AND PERSIST INTO NEW DAY 7. LOWS ARE
EXPECTED TO WARM A BIT MORE THRU THE PERIOD.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...VFR OVERNIGHT AND THRU DAYBREAK WITH A LIGHT NORTHEAST
BREEZE. A FEW STRATOCU AROUND 050 MAY DEVELOP IN MOIST MIDLEVEL FLOW
THIS EVENING BUT A CIG IS UNLIKELY OVER THE FIELD. NE WINDS CONTINUE
TOMORROW WITH MORE GUST POTENTIAL THAN THAT SEEN FRI...AS FLOW
STRENGTHENS BETWEEN SFC TROUGH APPROACHING FROM THE MISSISSIPPI
VALLEY AND ATLANTIC LOW PRESSURE. A FEW DIURNALLY DRIVEN CU MAY
DEVELOP ONCE AGAIN.
ELSEWHERE...SKIES SHOULD BE VIRTUALLY CLEAR TONIGHT AWAY FROM THE
BLUE RIDGE...WHERE MOIST EASTERLY MIDLEVEL FLOW IS GENERATING SOME
LOW VFR STRATOCU. THESE CLOUDS ARE EXPECTED TO DISSIPATE BY LATE
EVENING. MTN VALLEY FOG LOOKS LIKE A GOOD BET ONCE AGAIN. LIGHT
BREEZES WILL CONTINUE ACROSS THE REGION OVERNIGHT AND THIS IS THE
MAIN LIMITING FACTOR. ANY CIGS FROM THE STRATOCU COULD RETARD
COOLING AND PREVENT FOG...BUT THIS IS UNLIKELY. MOST GUIDANCE
SUPPORTS FOG AT KAVL AND ELSEWHERE IN THE VALLEYS...AS DOES
PERSISTENCE AND CLIMO. THUS TOOK KAVL TO LIFR. ON SATURDAY...NELY
WINDS CONTINUE WITH GUSTS A LITTLE STRONGER AND MORE FREQUENT AS
PRESSURE GRADIENT INCREASES BETWEEN TROUGH SWINGING THRU THE
MISSISSIPPI VALLEY AND THE STRENGTHENING LOW OVER THE WRN ATLANTIC.
DRY FCST THOUGH A FEW CU MAY BE SEEN AT VFR LEVEL.
OUTLOOK...DEEP HIGH PRESSURE WILL REMAIN ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA THRU THE WEEKEND. MTN VALLEY FOG MAY
DEVELOP AGAIN SUNDAY MORNING. A COLD FRONT APPROACHES THE REGION
MONDAY AND MONDAY NIGHT...BUT APPEARS TO WEAKEN BEFORE ARRIVING.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 85% MED 66% HIGH 97% HIGH 100%
KHKY HIGH 97% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...MCAVOY
LONG TERM...JPT
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1042 PM CDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 900 PM CDT FRI SEP 27 2013
FORECAST GENERALLY SEEMS TO BE IN GOOD SHAPE. HOWEVER SHOWERS WITH
EMBEDDED HEAVY RAIN FORMED A BIT FURTHER EAST THAN ORIGINALLY
EXPECTED...CLOSER TO THE LOW LEVEL FRONTAL ZONE. HRRR SHOWING A
COUPLE HUNDRED J/KG OF ELEVATED CAPE IN THIS AREA...ALLOWING FOR
EMBEDDED LIGHTNING. HOWEVER NONE OF THE STORMS ARE EVEN PUSHING
LIMITS WHERE SMALL HAIL WOULD BE POSSIBLE...AND SINCE THIS IS
ELEVATED AND IN THE COOLER AIRMASS...WIND SHOULD NOT BE AN ISSUE.
MEANWHILE...ANOTHER BAND OF RAIN IS EXPANDING ACROSS WEST CENTRAL
NEBRASKA AND SOUTH CENTRAL SOUTH DAKOTA...ASSOCIATED MORE WITH THE
MID LEVEL FRONT AND THE BETTER UPPER LEVEL SUPPORT. THE LEADING RAIN
BAND IS PROBABLY LIMITING MOISTURE TRANSPORT INTO THE TRIALING RAIN
AREA SOMEWHAT. EXPECT THE FIRST AREA TO CONTINUE MOVING NORTH
NORTHEAST...MAKING IT TO JUST WEST OF INTERSTATE 29 FROM SIOUX FALLS
TO BROOKINGS OVER THE NEXT FEW HOURS. THIS AREA SHOULD BEGIN TO
LESSON IN INTENSITY SOME AS MODELS SUGGEST THE ELEVATED INSTABILITY
DISSIPATES. THEN WOULD EXPECT THE TRIALING RAIN AREA ASSOCIATED WITH
THE MAIN WAVE TO TAKE OVER AND PUSH EAST RAPIDLY ACROSS THE AREA.
WHAT THIS ALL MEANS...IS THAT THE AXIS OF HIGHEST RAIN WILL PROBABLY
END UP A BIT EAST THAN ORIGINALLY FORECAST...AND MAY END UP FROM
EASTERN CHARLES MIX INTO BON HOMME COUNTIES...NORTH TOWARDS DAVIDSON
AND HANSON COUNTIES. BUT STILL EXPECTING EVERYONE TO GET WET
OVERNIGHT. DO NOT THINK WE SEE MUCH IN THE WAY OF LIGHTNING WITH THE
SECOND AREA OF RAIN WHEN IT MOVES THROUGH...ALTHOUGH WEAK ELEVATED
INSTABILITY NEAR THE MISSOURI RIVER MAY BE ENOUGH TO GET A FEW
EMBEDDED STORMS IN THAT AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 312 PM CDT FRI SEP 27 2013
SURFACE FRONT HAS MADE LITTLE HEADWAY ACROSS THE FORECAST AREA
TODAY. LIGHT BAND OF SHOWERS DEVELOPED IN SOUTH CENTRAL SOUTH DAKOTA
AND HAS MOVED NORTHEAST NEAR THE SURFACE FRONT. DUE TO STEEP LAPSE
RATES IN THE MID LEVELS...THERE IS A SMALL AMOUNT OF ELEVATED
INSTABILITY THAT MAY RESULT IN A FEW SPORADIC LIGHTNING STRIKES HERE
AND THERE. FURTHER TO THE WEST...ACROSS CENTRAL NEBRASKA SHOWERS
HAVE BEGUN TO DEVELOP ASSOCIATED WITH THE UPPER LEVEL WAVE AS UPPER
LEVEL SUPPORT AND STRONG FORCING DEVELOPS ACROSS THE AREA. EXPECT
PRECIPITATION TO BECOME FAIRLY WIDESPREAD ACROSS CENTRAL SOUTH
DAKOTA AS THE UPPER LEVEL WAVE LIFTS NORTHEAST. PWAT VALUES RANGE
FROM 1.3-1.5 INCHES WHICH IS NEAR TWO STANDARD DEVIATIONS. GIVEN
THE BULK OF THE UPPER LEVEL FORCING FOCUSES ACROSS THE WESTERN HALF
OF THE FORECAST AREA...EXPECT THE HEAVIEST PRECIPITATION AMOUNTS TO
BE ACROSS THE WEST.
OVERALL...MODELS HAVE CONTINUED TO TREND SLIGHTLY SLOWER WITH THE
SYSTEM SUGGESTING THAT PRECIPITATION WILL NOT REACH THE EASTERN EDGE
OF THE FORECAST AREA TILL NEAR 12Z. WITH STRONG UPPER LEVEL
WAVE...MODELS ARE HINTING AT LINGERING SHOWER ACTIVITY ASSOCIATED
WITH A TROWAL THROUGH THE NORTHERN EDGE OF THE FORECAST AREA ON
SATURDAY MORNING.
SKIES SHOULD GRADUALLY CLEAR THROUGHOUT THE DAY AS NORTHWEST WINDS
INCREASE ACROSS THE REGION DURING THE DAY. WITH CLEARING
SKIES...SHOULD SEE SOME PRETTY GOOD MIXING WITH GUSTY WINDS
LINGERING THROUGH THE EARLY EVENING HOURS. HAVE TWEAKED HIGH
TEMPERATURES DOWN SLIGHTLY ACROSS THE NORTHEASTERN CORNER OF THE
FORECAST AREA WHERE COLD CORE SYSTEM AND ASSOCIATED CLOUD COVER MAY
HAMPER MIXING SLIGHTLY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 312 PM CDT FRI SEP 27 2013
THE AIR IS EXPECTED TO REMAIN QUITE DRY AT ALL LEVELS TO BRING
CLEAR SKIES SATURDAY NIGHT THROUGH AT LEAST MONDAY. THE COOLING
SATURDAY NIGHT TO LOWS OF 40 TO 45 WILL GIVE WAY TO STRONG DAYTIME
WARMING UNDER MODEST SOUTHWESTERLY FLOW SUNDAY WITH 75 TO 80
HIGHS. LOWS CLOSE TO 50 SUNDAY NIGHT THEN HIGHS WITHIN 2 OR 3
DEGREES OF 80 MONDAY. A PLEASANTLY TOLERABLE BREEZE SUNDAY WILL BE
FOLLOWED BY BREEZY CONDITIONS MONDAY ESPECIALLY EAST. MONDAY NIGHT
AND EARLY TUESDAY WILL BRING THE PASSAGE OF A WEAK AND DRY COLD
FRONT DRIVEN BY WAVE MOVING EAST ACROSS CANADIAN BORDER AREA. A
BRIEF WESTERLY ZONAL TYPE FLOW WILL BE TEMPORARY...AND BE FOLLOWED
BY UPSTREAM WAVE DIGGING LONG WAVE TROUGH INTO THE WESTERN PLAINS
THURSDAY. THIS WILL BRING A CHANCE OF THUNDERSTORMS...THEN
SHOWERS...TO THE AREA THURSDAY THROUGH FRIDAY WITH COOLING BY
FRIDAY. THIS TROUGH SHOULD BE PROGRESSIVE SO THAT THE FIRST
OCTOBER WEEKEND...RIGHT AFTER THIS FORECAST PERIOD...TURNS OUT DRY
AND COOL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 1040 PM CDT FRI SEP 27 2013
A COLD FRONT WILL MOVE ACROSS THE AREA TONIGHT BRINGING AN AREA OF
RAIN THROUGH THE REGION. CURRENTLY VFR AT ALL TAF SITES...BUT EXPECT
CIGS AND VIS TO DROP INTO THE MVFR CATEGORY FROM WEST TO EAST AS THE
HEAVIER RAIN MOVES IN. THIS SHOULD HAPPEN AROUND KHON BY 04Z TO
05Z...INTERSTATE 29 CLOSER TO 07Z OR 08Z...AND SPENCER BY 12Z. MAY
EVEN SEE SOME BRIEF VIS REDUCTIONS TO IFR IN THE HEAVIER
ACTIVITY...WITH THE BEST CHANCE AT KHON WHERE THE HEAVIEST RAIN
IS EXPECTED. LIGHTNING THREAT SEEMS PRETTY LOW...ALTHOUGH AN
ISOLATED STRIKE OR TWO IS A POSSIBILITY...WITH THE BEST CHANCE ALONG
AND SOUTH OF THE MISSOURI RIVER. SOME IFR CIGS HAVE JUST DEVELOPED
IN NEBRASKA...SO OVERNIGHT SHIFT WILL HAVE TO MONITOR THEIR PROGRESS
AND ADJUST TAFS AS NECESSARY. THE RAIN WILL QUICKLY EXIT IN THE
MORNING...WITH STRATOCU GRADUALLY LIFTING TO VFR BY LATE MORNING.
LOOKS LIKE ENOUGH OF A DRY PUSH TO ALLOW THIS TO HAPPEN...BUT FUTURE
SHIFTS WILL NEED TO MONITOR...AS MVFR CIGS COULD LINGER A BIT LONGER
THAN CURRENTLY FORECAST. WINDS WILL BE BLUSTERY OUT OF THE WEST TO
NORTHWEST BEHIND THE FRONT TONIGHT INTO TOMORROW...WITH GUSTS OF 20
TO 25 KTS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
902 PM CDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 900 PM CDT FRI SEP 27 2013
FORECAST GENERALLY SEEMS TO BE IN GOOD SHAPE. HOWEVER SHOWERS WITH
EMBEDDED HEAVY RAIN FORMED A BIT FURTHER EAST THAN ORIGINALLY
EXPECTED...CLOSER TO THE LOW LEVEL FRONTAL ZONE. HRRR SHOWING A
COUPLE HUNDRED J/KG OF ELEVATED CAPE IN THIS AREA...ALLOWING FOR
EMBEDDED LIGHTNING. HOWEVER NONE OF THE STORMS ARE EVEN PUSHING
LIMITS WHERE SMALL HAIL WOULD BE POSSIBLE...AND SINCE THIS IS
ELEVATED AND IN THE COOLER AIRMASS...WIND SHOULD NOT BE AN ISSUE.
MEANWHILE...ANOTHER BAND OF RAIN IS EXPANDING ACROSS WEST CENTRAL
NEBRASKA AND SOUTH CENTRAL SOUTH DAKOTA...ASSOCIATED MORE WITH THE
MID LEVEL FRONT AND THE BETTER UPPER LEVEL SUPPORT. THE LEADING RAIN
BAND IS PROBABLY LIMITING MOISTURE TRANSPORT INTO THE TRIALING RAIN
AREA SOMEWHAT. EXPECT THE FIRST AREA TO CONTINUE MOVING NORTH
NORTHEAST...MAKING IT TO JUST WEST OF INTERSTATE 29 FROM SIOUX FALLS
TO BROOKINGS OVER THE NEXT FEW HOURS. THIS AREA SHOULD BEGIN TO
LESSON IN INTENSITY SOME AS MODELS SUGGEST THE ELEVATED INSTABILITY
DISSIPATES. THEN WOULD EXPECT THE TRIALING RAIN AREA ASSOCIATED WITH
THE MAIN WAVE TO TAKE OVER AND PUSH EAST RAPIDLY ACROSS THE AREA.
WHAT THIS ALL MEANS...IS THAT THE AXIS OF HIGHEST RAIN WILL PROBABLY
END UP A BIT EAST THAN ORIGINALLY FORECAST...AND MAY END UP FROM
EASTERN CHARLES MIX INTO BON HOMME COUNTIES...NORTH TOWARDS DAVIDSON
AND HANSON COUNTIES. BUT STILL EXPECTING EVERYONE TO GET WET
OVERNIGHT. DO NOT THINK WE SEE MUCH IN THE WAY OF LIGHTNING WITH THE
SECOND AREA OF RAIN WHEN IT MOVES THROUGH...ALTHOUGH WEAK ELEVATED
INSTABILITY NEAR THE MISSOURI RIVER MAY BE ENOUGH TO GET A FEW
EMBEDDED STORMS IN THAT AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 312 PM CDT FRI SEP 27 2013
SURFACE FRONT HAS MADE LITTLE HEADWAY ACROSS THE FORECAST AREA
TODAY. LIGHT BAND OF SHOWERS DEVELOPED IN SOUTH CENTRAL SOUTH DAKOTA
AND HAS MOVED NORTHEAST NEAR THE SURFACE FRONT. DUE TO STEEP LAPSE
RATES IN THE MID LEVELS...THERE IS A SMALL AMOUNT OF ELEVATED
INSTABILITY THAT MAY RESULT IN A FEW SPORADIC LIGHTNING STRIKES HERE
AND THERE. FURTHER TO THE WEST...ACROSS CENTRAL NEBRASKA SHOWERS
HAVE BEGUN TO DEVELOP ASSOCIATED WITH THE UPPER LEVEL WAVE AS UPPER
LEVEL SUPPORT AND STRONG FORCING DEVELOPS ACROSS THE AREA. EXPECT
PRECIPITATION TO BECOME FAIRLY WIDESPREAD ACROSS CENTRAL SOUTH
DAKOTA AS THE UPPER LEVEL WAVE LIFTS NORTHEAST. PWAT VALUES RANGE
FROM 1.3-1.5 INCHES WHICH IS NEAR TWO STANDARD DEVIATIONS. GIVEN
THE BULK OF THE UPPER LEVEL FORCING FOCUSES ACROSS THE WESTERN HALF
OF THE FORECAST AREA...EXPECT THE HEAVIEST PRECIPITATION AMOUNTS TO
BE ACROSS THE WEST.
OVERALL...MODELS HAVE CONTINUED TO TREND SLIGHTLY SLOWER WITH THE
SYSTEM SUGGESTING THAT PRECIPITATION WILL NOT REACH THE EASTERN EDGE
OF THE FORECAST AREA TILL NEAR 12Z. WITH STRONG UPPER LEVEL
WAVE...MODELS ARE HINTING AT LINGERING SHOWER ACTIVITY ASSOCIATED
WITH A TROWAL THROUGH THE NORTHERN EDGE OF THE FORECAST AREA ON
SATURDAY MORNING.
SKIES SHOULD GRADUALLY CLEAR THROUGHOUT THE DAY AS NORTHWEST WINDS
INCREASE ACROSS THE REGION DURING THE DAY. WITH CLEARING
SKIES...SHOULD SEE SOME PRETTY GOOD MIXING WITH GUSTY WINDS
LINGERING THROUGH THE EARLY EVENING HOURS. HAVE TWEAKED HIGH
TEMPERATURES DOWN SLIGHTLY ACROSS THE NORTHEASTERN CORNER OF THE
FORECAST AREA WHERE COLD CORE SYSTEM AND ASSOCIATED CLOUD COVER MAY
HAMPER MIXING SLIGHTLY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 312 PM CDT FRI SEP 27 2013
THE AIR IS EXPECTED TO REMAIN QUITE DRY AT ALL LEVELS TO BRING
CLEAR SKIES SATURDAY NIGHT THROUGH AT LEAST MONDAY. THE COOLING
SATURDAY NIGHT TO LOWS OF 40 TO 45 WILL GIVE WAY TO STRONG DAYTIME
WARMING UNDER MODEST SOUTHWESTERLY FLOW SUNDAY WITH 75 TO 80
HIGHS. LOWS CLOSE TO 50 SUNDAY NIGHT THEN HIGHS WITHIN 2 OR 3
DEGREES OF 80 MONDAY. A PLEASANTLY TOLERABLE BREEZE SUNDAY WILL BE
FOLLOWED BY BREEZY CONDITIONS MONDAY ESPECIALLY EAST. MONDAY NIGHT
AND EARLY TUESDAY WILL BRING THE PASSAGE OF A WEAK AND DRY COLD
FRONT DRIVEN BY WAVE MOVING EAST ACROSS CANADIAN BORDER AREA. A
BRIEF WESTERLY ZONAL TYPE FLOW WILL BE TEMPORARY...AND BE FOLLOWED
BY UPSTREAM WAVE DIGGING LONG WAVE TROUGH INTO THE WESTERN PLAINS
THURSDAY. THIS WILL BRING A CHANCE OF THUNDERSTORMS...THEN
SHOWERS...TO THE AREA THURSDAY THROUGH FRIDAY WITH COOLING BY
FRIDAY. THIS TROUGH SHOULD BE PROGRESSIVE SO THAT THE FIRST
OCTOBER WEEKEND...RIGHT AFTER THIS FORECAST PERIOD...TURNS OUT DRY
AND COOL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT FRI SEP 27 2013
A COLD FRONT WILL MOVE ACROSS THE AREA TONIGHT BRINGING AN AREA OF
RAIN THROUGH THE REGION. CURRENTLY VFR AT ALL TAF SITES...BUT EXPECT
CIGS AND VIS TO DROP INTO THE MVFR CATEGORY FROM WEST TO EAST AS THE
HEAVIER RAIN MOVES IN. THIS SHOULD HAPPEN AROUND KHON BY
02Z...INTERSTATE 29 CLOSER TO 07Z OR 08Z...AND SPENCER BY 12Z. MAY EVEN
SEE SOME BRIEF REDUCTIONS TO IFR IN THE HEAVIER ACTIVITY...ALTHOUGH
WILL LEAVE THAT OUT OF THE TAFS FOR NOW. LIGHTNING THREAT SEEMS
PRETTY LOW...ALTHOUGH AN ISOLATED STRIKE OR TWO IS A
POSSIBILITY...WITH THE BEST CHANCE ALONG AND SOUTH OF THE MISSOURI
RIVER. THE RAIN WILL QUICKLY EXIT IN THE MORNING...WITH STRATOCU
GRADUALLY LIFTING TO VFR BY LATE MORNING. LOOKS LIKE ENOUGH OF A DRY
PUSH TO ALLOW THIS TO HAPPEN...BUT FUTURE SHIFTS WILL NEED TO
MONITOR...AS MVFR CIGS COULD LINGER A BIT LONGER THAN CURRENTLY
FORECAST. WINDS WILL BE BLUSTERY OUT OF THE WEST TO NORTHWEST BEHIND
THE FRONT TONIGHT INTO TOMORROW...WITH GUSTS OF 20 TO 25 KTS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1047 PM CDT FRI SEP 27 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 204 PM CDT FRI SEP 27 2013
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE MOVING OVER EASTERN NORTH AMERICA...WHILE A COLD FRONT IS
SHIFTING EVER SO SLIGHTLY TO THE EAST ACROSS THE GREAT PLAINS AND
NORTHERN MISSISSIPPI VALLEY. A FEW SHOWERS HAVE PUSHED INTO FAR
NORTHWEST WISCONSIN AHEAD OF THE FRONT AND A MID-DECK IS JUST
BRUSHING PAST N-C WISCONSIN. OTHERWISE...MAINLY CLEAR SKIES EXIST
ACROSS THE FORECAST AREA EARLY THIS AFTERNOON WITH TEMPS IN THE MID
70S TO LOW 80S. AS THE COLD FRONT GRADUALLY MOVES EAST OVER THE
NEXT 24 HOURS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN THROUGH
SATURDAY.
TONIGHT...THE COLD FRONT OVER THE NORTHERN MISSISSIPPI VALLEY WILL
MAKE LITTLE PROGRESS TO THE EAST. MID AND UPPER LEVEL DRY AIR OVER
IOWA AND MISSOURI WILL PUSH THE CLOUD COVER OVER NORTHWEST WISCONSIN
NORTH OF THE REGION LATE IN THE EVENING AND OVERNIGHT...WHICH WILL
SET UP A PERIOD OF CLEAR SKIES ACROSS THE FORECAST AREA. UNLIKE THE
PAST FEW NIGHTS...A DECENT PRESSURE GRADIENT WILL BE IN PLACE...SO
WILL NOT HAVE TO WORRY ABOUT FOG FORMATION. LOW TEMPS WILL BE
SEVERAL DEGREES WARMER THAN LAST NIGHT...AND WILL GO WITH MINS IN
THE LOW TO MID 50S.
SATURDAY...CLOUDS WILL BE ON THE INCREASE DURING THE MORNING AS A
STRONG SHORTWAVE FINALLY PUSHES THE COLD FRONT TO THE EAST. MODELS
POINT TOWARD SHOWERS ARRIVING AHEAD OF THE FRONT ACROSS WESTERN
SECTIONS OF THE FORECAST AREA DURING THE EARLY TO MIDDLE AFTERNOON
HOURS. THE FRONT WILL HAVE PWATS UPWARDS OF 1.5 INCHES...AND PLENTY
OF FORCING ALOFT IN THE FORM OF MID-LEVEL FGEN AND DPVA...SO WILL
INCREASE POPS ACROSS THE WESTERN HALF TO NEARLY 100 PCT. THE ONLY
THING LACK IS INSTABILITY SINCE MID-LEVEL LAPSE RATES ARE BETWEEN 5
AND 6 C/KM AND 850-700MB THETAE LAPSE RATES ARE POSITIVE. MODIFYING
A FEW SOUNDINGS SHOW CAPES BETWEEN 50-100 J/KG...SO AN ISOLATED
LIGHTNING STRIKE SEEMS POSSIBLE. SLOWED DOWN THE PRECIP ACROSS THE
EAST A BIT AS MOST MODELS KEEP THE LAKE MICHIGAN SHORELINE DRY
THROUGH 00Z. HIGHS REACHING FROM THE MID TO UPPER 70S...THEN
COOLING AS CLOUDS INCREASE AND RAIN ARRIVES.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 204 PM CDT FRI SEP 27 2013
TROF LIFTS OUT OF CENTRAL US ON SUNDAY WITH LESS
AMPLIFIED/PROGRESSIVE FLOW OVER CONUS THROUGH LATE NEXT WEEK.
THROUGH WED...BRUNT OF SHORT WAVE ACTIVITY TO PASS NORTH AND
WEST OF CWA. TAIL END OF SFC FRONT TO PASS THROUGH TUE/WED
PERIOD...THOUGH MOISTURE LIMITED SO EXPECTED TO COME THROUGH DRY.
RATHER MILD PERIOD EXPECTED WITH HIGHS AROUND 70 AND LOWS IN THE
50S.
BY THU...SEE MORE AMPLIFICATION WITH TROF IN THE WEST...THOUGH
PATTERN STILL PROGRESSIVE. MOISTURE EXPECTED TO LIFT NORTH OUT OF
GULF AHEAD OF SYSTEM...WITH SFC WARM FRONT EXPECTED TO BE OVER OR
NEAR STATE ON THU. HAVE CONTINUED CHANCE POPS FOR WED/THU...GIVEN
UNCERTAINTY. COLD FRONT TO APPROACH LATER FRI.
IN NEAR TERM...WILL CONTINUE WITH PROGRESSING FRONT THROUGH REGION
SAT EVENING...ENDING PCPN ALONG LAKESHORE BETWEEN 06Z-09Z. HIGH
PRESSURE TO MOVE IN FOR MOSTLY SUNNY AND DRY DAY. TEMPERATURES SUN
TO RUN NEAR OR ABOVE NORMAL.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1047 PM CDT FRI SEP 27 2013
VFR CONDITIONS EXPECTED REST OF TONIGHT INTO EARLY
SATURDAY...WITH THE EXCEPTION OF SOME PATCHY MVFR FOG ALONG THE
LAKESHORE. OVERNIGHT LLWS CONDITIONS WILL LINGER TO AROUND 15Z BEFORE
BEING REPLACED BY GUSTY SURFACE WINDS LATER SATURDAY MORNING.
FOR SATURDAY AFTERNOON AND EVENING...A BAND OF SHOWERS WITH MVFR
CIGS ALONG A COLD FRONT WILL MOVE ACROSS THE STATE. LATEST TRENDS
INDICATE THE BAND OF SHOWERS WILL BE DEPARTING TO THE EAST OF
CENTRAL AND NORTH CENTRAL LATE SATURDAY EVENING...FOLLOWED WITH A
RETURN TO VFR CONDITIONS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
641 PM CDT FRI SEP 27 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 204 PM CDT FRI SEP 27 2013
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE MOVING OVER EASTERN NORTH AMERICA...WHILE A COLD FRONT IS
SHIFTING EVER SO SLIGHTLY TO THE EAST ACROSS THE GREAT PLAINS AND
NORTHERN MISSISSIPPI VALLEY. A FEW SHOWERS HAVE PUSHED INTO FAR
NORTHWEST WISCONSIN AHEAD OF THE FRONT AND A MID-DECK IS JUST
BRUSHING PAST N-C WISCONSIN. OTHERWISE...MAINLY CLEAR SKIES EXIST
ACROSS THE FORECAST AREA EARLY THIS AFTERNOON WITH TEMPS IN THE MID
70S TO LOW 80S. AS THE COLD FRONT GRADUALLY MOVES EAST OVER THE
NEXT 24 HOURS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN THROUGH
SATURDAY.
TONIGHT...THE COLD FRONT OVER THE NORTHERN MISSISSIPPI VALLEY WILL
MAKE LITTLE PROGRESS TO THE EAST. MID AND UPPER LEVEL DRY AIR OVER
IOWA AND MISSOURI WILL PUSH THE CLOUD COVER OVER NORTHWEST WISCONSIN
NORTH OF THE REGION LATE IN THE EVENING AND OVERNIGHT...WHICH WILL
SET UP A PERIOD OF CLEAR SKIES ACROSS THE FORECAST AREA. UNLIKE THE
PAST FEW NIGHTS...A DECENT PRESSURE GRADIENT WILL BE IN PLACE...SO
WILL NOT HAVE TO WORRY ABOUT FOG FORMATION. LOW TEMPS WILL BE
SEVERAL DEGREES WARMER THAN LAST NIGHT...AND WILL GO WITH MINS IN
THE LOW TO MID 50S.
SATURDAY...CLOUDS WILL BE ON THE INCREASE DURING THE MORNING AS A
STRONG SHORTWAVE FINALLY PUSHES THE COLD FRONT TO THE EAST. MODELS
POINT TOWARD SHOWERS ARRIVING AHEAD OF THE FRONT ACROSS WESTERN
SECTIONS OF THE FORECAST AREA DURING THE EARLY TO MIDDLE AFTERNOON
HOURS. THE FRONT WILL HAVE PWATS UPWARDS OF 1.5 INCHES...AND PLENTY
OF FORCING ALOFT IN THE FORM OF MID-LEVEL FGEN AND DPVA...SO WILL
INCREASE POPS ACROSS THE WESTERN HALF TO NEARLY 100 PCT. THE ONLY
THING LACK IS INSTABILITY SINCE MID-LEVEL LAPSE RATES ARE BETWEEN 5
AND 6 C/KM AND 850-700MB THETAE LAPSE RATES ARE POSITIVE. MODIFYING
A FEW SOUNDINGS SHOW CAPES BETWEEN 50-100 J/KG...SO AN ISOLATED
LIGHTNING STRIKE SEEMS POSSIBLE. SLOWED DOWN THE PRECIP ACROSS THE
EAST A BIT AS MOST MODELS KEEP THE LAKE MICHIGAN SHORELINE DRY
THROUGH 00Z. HIGHS REACHING FROM THE MID TO UPPER 70S...THEN
COOLING AS CLOUDS INCREASE AND RAIN ARRIVES.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 204 PM CDT FRI SEP 27 2013
TROF LIFTS OUT OF CENTRAL US ON SUNDAY WITH LESS
AMPLIFIED/PROGRESSIVE FLOW OVER CONUS THROUGH LATE NEXT WEEK.
THROUGH WED...BRUNT OF SHORT WAVE ACTIVITY TO PASS NORTH AND
WEST OF CWA. TAIL END OF SFC FRONT TO PASS THROUGH TUE/WED
PERIOD...THOUGH MOISTURE LIMITED SO EXPECTED TO COME THROUGH DRY.
RATHER MILD PERIOD EXPECTED WITH HIGHS AROUND 70 AND LOWS IN THE
50S.
BY THU...SEE MORE AMPLIFICATION WITH TROF IN THE WEST...THOUGH
PATTERN STILL PROGRESSIVE. MOISTURE EXPECTED TO LIFT NORTH OUT OF
GULF AHEAD OF SYSTEM...WITH SFC WARM FRONT EXPECTED TO BE OVER OR
NEAR STATE ON THU. HAVE CONTINUED CHANCE POPS FOR WED/THU...GIVEN
UNCERTAINTY. COLD FRONT TO APPROACH LATER FRI.
IN NEAR TERM...WILL CONTINUE WITH PROGRESSING FRONT THROUGH REGION
SAT EVENING...ENDING PCPN ALONG LAKESHORE BETWEEN 06Z-09Z. HIGH
PRESSURE TO MOVE IN FOR MOSTLY SUNNY AND DRY DAY. TEMPERATURES SUN
TO RUN NEAR OR ABOVE NORMAL.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 640 PM CDT FRI SEP 27 2013
VFR CONDITIONS EXPECTED TONIGHT INTO EARLY SATURDAY.
LATER THIS EVENING AS WINDS DIMINISH AT THE SURFACE...INCREASING
WINDS AT 2000 FEET AGL WILL PRODUCE LLWS CONDITIONS OVERNIGHT. THE
LLWS CONDITIONS WILL BE REPLACED BY GUSTY SURFACE WINDS SATURDAY
MORNING.
SATURDAY AFTERNOON AND EVENING...A BAND OF SHOWERS WITH MVFR CIGS
ALONG A COLD FRONT WILL MOVE ACROSS THE STATE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
545 PM CDT THU SEP 26 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 231 PM CDT THU SEP 26 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
STRETCHING FROM NORTHERN QUEBEC TO THE WESTERN GREAT LAKES EARLY
THIS AFTERNOON. MEANWHILE...A LOW PRESSURE AND COLD FRONT ARE
SLOWLY MOVING EAST OVER THE NORTHERN PLAINS. MOST OF THE FOG BURNED
OFF BY 16Z...LEAVING SUNNY SKIES ACROSS THE REGION. WITH
PLENTY OF CLEAR SKIES ALL THE WAY TO THE COLD FRONT...FOG AGAIN IS
THE MAIN FORECAST CONCERN TONIGHT...FOLLOWED BY TEMPERATURES ON
FRIDAY.
TONIGHT...THE MID-LEVEL RIDGE WILL REMAIN IN CLOSE PROXIMITY TO THE
REGION...WHILE SURFACE HIGH PRESSURE DRIFTS A LITTLE EASTWARD. AS A
COLD FRONT MOVES TOWARDS THE NORTHERN MISSISSIPPI VALLEY...THE LOW
LEVEL PRESSURE GRADIENT WILL BE TIGHTENING WHICH WILL RESULT IN
1000-850MB WINDS OF 15-20 KTS. THOUGH THE BL WILL BE MORE
MIXY...THE NAM IS STILL DEPICTING CALM WINDS OVER NORTHEAST
WISCONSIN LATE TONIGHT. SO UNFORTUNATELY...FOG WILL REMAIN A
CONCERN...JUST NOT AS MUCH AS YESTERDAY. WILL STILL SHOW AREAS
OF FOG NORTH OF THE FOX VALLEY AND WOULD NOT BE SURPRISED TO SEE
SOME PATCHY DENSE FOG SHOW UP. WILL LEAVE A PATCHY FOG MENTION OVER
CENTRAL AND EAST-CENTRAL WISCONSIN. LOWS WILL CONTINUE THEIR
WARMING TREND...AND WILL GO WITH MID 40S NORTH TO LOW 50S SOUTH AND
WEST.
FRIDAY...ONCE ANY FOG BURNS OFF EARLY...WILL SEE ANOTHER SUNNY DAY
AS THE FRONT WILL REMAIN OVER THE NORTHERN MISSISSIPPI VALLEY.
WARMER AIR WILL INVADE THE REGION...WHICH WILL PUSH HIGHS INTO THE
MID 70S TO LOW 80S. SOUTHEAST WINDS WILL ALSO BECOME GUSTY.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 231 PM CDT THU SEP 26 2013
MAIN ISSUE THIS PERIOD...PCPN SAT. TIMING DIFFERENCES CONTINUE TO
BE SEEN WITH COLD FRONT/UPPER SHORT WAVE EXPECTED TO CROSS STATE
SAT/SAT NIGHT. LITTLE CHANGE IN PREVIOUS THOUGHTS WITH PCPN TIED
TO FRONT...GOOD MOISTURE CONVERGENCE AND SOME UPPER DIVERGENCE
WITH JET LIFTING NORTH INTO CANADA. MAIN DYNAMICS WITH SHORT WAVE
LIFT NORTH AND WEST OF CWA...HAVE CARRIED HIGHEST POPS SAT AFTN
OVER FAR NORTH. INSTABILITY WEAK AND DIMINISHES FURTHER AS MOVES
INTO WI. HAVE LIMITED THUNDER TO JUST SAT AFTERNOON. MODELS
CONTINUE TO SHOW THE RAIN MOVING THROUGH THE AREA RATHER
QUICKLY. HAVE CONFINED POPS TO BETWEEN NOON AND MIDNIGHT SAT.
A MORE ZONAL UPPER LEVEL FLOW PATTERN EXPECTED THROUGH MID WEEK.
ISSUES WITH HOW MODELS HANDLING PACIFIC ENERGY LATER IN THE
PERIOD. PCPN CHANCES THROUGH WED LOW...THUS HAVE REMOVED SMALL
POPS KEEPING CHANCE ON THU AS FLOW BECOMES A BIT MORE AMPLIFIED.
MUCH ABOVE NORMAL TEMPERATURES AHEAD OF THE APPROACHING COLD
FRONT WITH GUSTY SOUTH WINDS ON SAT...WILL GIVE WAY TO
COOLER...BUT STILL ABOVE NORMAL DAYTIME HIGHS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 544 PM CDT THU SEP 26 2013
SLIGHTLY DIFFERENT WX PATTERN TNGT...BUT STILL EXPECTING ISSUES
WITH FOG. SFC HIGH HAS EDGED A BIT FARTHER E...WITH FRONTAL
SYSTEM NOW BEGINNING TO SLOWLY ADVANCE E FM THE NRN PLAINS. THOSE
CHGS WL RESULT IN A LITTLE STRONGER SFC PRESSURE GRADIENT ACRS THE
AREA TNGT...ESP ACRS THE WRN 1/2 OF THE FCST AREA. WINDS ATOP THE
BOUNDARY LAYER WL ALSO BE A BIT STRONGER. THOSE FACTORS WOULD SEEM
SUFFICIENT TO PREVENT SIG FOG FORMATION. HOWEVER...BASED ON WHAT/S
HAPPENED THE PAST FEW NIGHTS...DON/T THINK THEY WL BE ABLE TO
HOLD THE FOG OFF...ESP IN THE E. WL HIT FOG MUCH HARDER IN THE ERN
TAF SITES. WL TREND SOMEWHAT MORE PESSIMISTIC ACRS THE W
ALSO...THOUGH CONDITIONS THERE SHOULD NOT BE AS BAD AS THE PAST
FEW MORNINGS.
&&
.MARINE...
ISSUED AT 231 PM CDT THU SEP 26 2013
AN EXTENDED PERIOD OF SOUTHERLY WINDS FRIDAY NIGHT AND
SATURDAY WILL BUILD WAVES OVER LAKE MICHIGAN WITH SMALL CRAFT
CONDITIONS EXPECTED.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......SKOWRONSKI
MARINE.........TE
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 231 PM CDT THU SEP 26 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
STRETCHING FROM NORTHERN QUEBEC TO THE WESTERN GREAT LAKES EARLY
THIS AFTERNOON. MEANWHILE...A LOW PRESSURE AND COLD FRONT ARE
SLOWLY MOVING EAST OVER THE NORTHERN PLAINS. MOST OF THE FOG BURNED
OFF BY 16Z...LEAVING SUNNY SKIES ACROSS THE REGION. WITH
PLENTY OF CLEAR SKIES ALL THE WAY TO THE COLD FRONT...FOG AGAIN IS
THE MAIN FORECAST CONCERN TONIGHT...FOLLOWED BY TEMPERATURES ON
FRIDAY.
TONIGHT...THE MID-LEVEL RIDGE WILL REMAIN IN CLOSE PROXIMITY TO THE
REGION...WHILE SURFACE HIGH PRESSURE DRIFTS A LITTLE EASTWARD. AS A
COLD FRONT MOVES TOWARDS THE NORTHERN MISSISSIPPI VALLEY...THE LOW
LEVEL PRESSURE GRADIENT WILL BE TIGHTENING WHICH WILL RESULT IN
1000-850MB WINDS OF 15-20 KTS. THOUGH THE BL WILL BE MORE
MIXY...THE NAM IS STILL DEPICTING CALM WINDS OVER NORTHEAST
WISCONSIN LATE TONIGHT. SO UNFORTUNATELY...FOG WILL REMAIN A
CONCERN...JUST NOT AS MUCH AS YESTERDAY. WILL STILL SHOW AREAS
OF FOG NORTH OF THE FOX VALLEY AND WOULD NOT BE SURPRISED TO SEE
SOME PATCHY DENSE FOG SHOW UP. WILL LEAVE A PATCHY FOG MENTION OVER
CENTRAL AND EAST-CENTRAL WISCONSIN. LOWS WILL CONTINUE THEIR
WARMING TREND...AND WILL GO WITH MID 40S NORTH TO LOW 50S SOUTH AND
WEST.
FRIDAY...ONCE ANY FOG BURNS OFF EARLY...WILL SEE ANOTHER SUNNY DAY
AS THE FRONT WILL REMAIN OVER THE NORTHERN MISSISSIPPI VALLEY.
WARMER AIR WILL INVADE THE REGION...WHICH WILL PUSH HIGHS INTO THE
MID 70S TO LOW 80S. SOUTHEAST WINDS WILL ALSO BECOME GUSTY.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 231 PM CDT THU SEP 26 2013
MAIN ISSUE THIS PERIOD...PCPN SAT. TIMING DIFFERENCES CONTINUE TO
BE SEEN WITH COLD FRONT/UPPER SHORT WAVE EXPECTED TO CROSS STATE
SAT/SAT NIGHT. LITTLE CHANGE IN PREVIOUS THOUGHTS WITH PCPN TIED
TO FRONT...GOOD MOISTURE CONVERGENCE AND SOME UPPER DIVERGENCE
WITH JET LIFTING NORTH INTO CANADA. MAIN DYNAMICS WITH SHORT WAVE
LIFT NORTH AND WEST OF CWA...HAVE CARRIED HIGHEST POPS SAT AFTN
OVER FAR NORTH. INSTABILITY WEAK AND DIMINISHES FURTHER AS MOVES
INTO WI. HAVE LIMITED THUNDER TO JUST SAT AFTERNOON. MODELS
CONTINUE TO SHOW THE RAIN MOVING THROUGH THE AREA RATHER
QUICKLY. HAVE CONFINED POPS TO BETWEEN NOON AND MIDNIGHT SAT.
A MORE ZONAL UPPER LEVEL FLOW PATTERN EXPECTED THROUGH MID WEEK.
ISSUES WITH HOW MODELS HANDLING PACIFIC ENERGY LATER IN THE
PERIOD. PCPN CHANCES THROUGH WED LOW...THUS HAVE REMOVED SMALL
POPS KEEPING CHANCE ON THU AS FLOW BECOMES A BIT MORE AMPLIFIED.
MUCH ABOVE NORMAL TEMPERATURES AHEAD OF THE APPROACHING COLD
FRONT WITH GUSTY SOUTH WINDS ON SAT...WILL GIVE WAY TO
COOLER...BUT STILL ABOVE NORMAL DAYTIME HIGHS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1239 PM CDT THU SEP 26 2013
HIGH PRESSURE WILL DEPART TO THE EAST AS A COLD FRONT
MOVES ACROSS THE NORTHERN PLAINS OVER THE PERIOD. BETWEEN THE TWO
SYSTEMS...WINDS WILL BE GRADUALLY INCREASING FROM THE
SOUTH-SOUTHEAST. THE WINDS WILL ALLEVIATE FOG CONCERNS
TONIGHT...BUT STILL DROPPED VSBYS AT THE TAF SITES INTO THE IFR/MVFR
RANGE LATE. PATCHY DENSE FOG MAY STILL BE POSSIBLE NORTH OF THE FOX
VALLEY. ONCE ANY FOG LIFTS FRIDAY MORNING...SOUTH WINDS WILL TURN
GUSTY BUT OTHERWISE...GOOD FLYING WEATHER WILL BE PRESENT.
&&
.MARINE...
ISSUED AT 231 PM CDT THU SEP 26 2013
AN EXTENDED PERIOD OF SOUTHERLY WINDS FRIDAY NIGHT AND
SATURDAY WILL BUILD WAVES OVER LAKE MICHIGAN WITH SMALL CRAFT
CONDITIONS EXPECTED.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC
MARINE.........TE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
103 PM CDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT THU SEP 26 2013
AT 3 AM...A 1020 MB HIGH WAS CENTERED NORTH OF LAKE HURON.
EASTERLY WINDS ON THE SOUTHERN PERIPHERY OF THIS HIGH CONTINUES TO
BRING LOWER AND MID 40 DEW POINTS INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN. THE COMBINATION OF THESE DEW POINTS ALONG WITH CLEAR
SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES THESE AREAS TO COOL
INTO THE LOWER AND MID 40S. WITH THESE TEMPERATURES COOLER THAN
THE WATER TEMPERATURES...STEAM FOG HAS DEVELOPED IN THIS AREA.
THERE ARE EVEN A FEW REPORTS OF DENSE FOG AT VOLK FIELD AND WAUTOMA.
WITH BUFKIT RAP SOUNDINGS CONTINUING TO SHOW THAT THE WINDS BELOW
900 MB WILL BE INCREASING TO AROUND 10 KNOTS BY SUNRISE...NOT
EXPECTING THIS FOG TO BECOME AS WIDESPREAD AS WEDNESDAY MORNING.
HOWEVER WITH THIS SAID...WE ARE STILL CONSIDERING A DENSE FOG
ADVISORY IN ADAMS AND JUNEAU COUNTIES IN CENTRAL WISCONSIN.
SHERIFF DEPARTMENTS IN BOTH OF THESE COUNTIES ARE REPORTING
PATCHY DENSE FOG. THE RAP WOULD SUGGEST THAT THE LOW LEVEL
MOISTURE WILL INCREASE THROUGH THE REMAINDER OF THIS MORNING.
MEANWHILE NAM/WRF SHOWS THAT THIS LOW LEVEL MOISTURE MIXES OUT BY
26.14Z.
FOR TODAY...HIGH PRESSURE WILL PROVIDE ANOTHER SUNNY DAY ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY. AS DIURNAL HEATING MIXES OUT
THE NOCTURNAL INVERSION THIS MORNING...EXPECT WIND GUSTS TO CLIMB
INTO THE 15 TO 30 MPH BETWEEN 10 AM AND NOON...AND THEN CONTINUE
THROUGH THE AFTERNOON. LIKE YESTERDAY...IT LOOKS LIKE THE AREA
WILL MIX TO AROUND 875 MB. THIS WILL YIELD TEMPERATURES IN THE
LOWER TO MID 70S NORTH OF INTERSTATE 94...AND FROM THE MID 70S TO
AROUND 80 ACROSS THE REMAINDER OF THE AREA.
FOR TONIGHT...THE CENTER OF SURFACE HIGH WILL DRIFT EAST INTO
QUEBEC. THIS WILL ALLOW THE COLD FRONT...CURRENTLY LOCATED OVER
THE CENTRAL DAKOTAS...TO MOVE EAST INTO WESTERN AND NORTHERN
MINNESOTA. AS THIS OCCURS...SOME MOISTURE BETWEEN 600 AND 700 MB
WILL MOVE EAST INTO THE FORECAST AFTER AFTER 27.08Z. THE NOCTURNAL
INVERSION WILL QUICKLY THIS EVENING WITH THE LOSS OF DIURNAL
HEATING. AS THIS OCCURS...THE WIND GUSTS WILL DIMINISH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 321 AM CDT THU SEP 26 2013
FROM FRIDAY AFTERNOON INTO FRIDAY NIGHT...THE 26.00Z MODELS ARE
IN VERY GOOD AGREEMENT THAT THE COLD FRONT WILL MOVE EAST INTO
WESTERN MINNESOTA DURING THE AFTERNOON AND EVENING...AND THEN IT
STALLS ITS EASTWARD PROGRESS ON FRIDAY NIGHT AS A SURFACE LOW
MOVES NORTH ALONG IT. WITH SOUNDINGS CONTINUING TO SHOW CAPPING
BETWEEN 800 AND 650 MBS AND DRY AIR AHEAD OF THIS FRONT...NOT
EXPECTING ANY PRECIPITATION TO OCCUR AHEAD OF IT....THUS KEPT THE
FORECAST DRY.
FROM SATURDAY INTO SATURDAY EVENING...THE MODELS CONTINUE TO SHOW
THAT THE SURFACE COLD FRONT AND SHORT WAVE TROUGH WILL MOVE
QUICKLY EAST ACROSS THE AREA. LIKE THE PAST DAYS...THE 0-6 KM
SHEAR REMAINS ABOVE 40 KNOTS ALONG AND IN THE WAKE OF THE FRONT.
HOWEVER THE ML CAPES REMAIN GENERALLY LESS THAN 100 J/KG...SO
STILL NOT CONCERNED THAT THE AREA WILL EXPERIENCE ANY SEVERE
WEATHER. JUST TOO LITTLE INSTABILITY FOR THE AMOUNT SHEAR.
OVERALL...ACTUALLY THINK THAT OUR BEST CHANCE OF THUNDER WILL
ACTUALLY COME FROM MORE SLANTWISE THAN UPRIGHT CONVECTION. DUE TO
THE CONSISTENCY OF THE TIMING WITH THE FRONTOGENESIS...RAISED THE
PRECIPITATION CHANCES INTO THE 75 TO 84 PERCENT RANGE. THINKING
WITH THE SPEED OF THE SHORT WAVE TROUGH AND FRONT THAT THE
PRECIPITATION WILL LIKELY ONLY LAST 2 TO 4 HOURS IN ANY LOCATION.
FROM TUESDAY INTO WEDNESDAY...THE MODELS ARE NOW SHOWING THAT THE
SHORT WAVE WILL PASS WELL NORTH OF THE AREA. DUE TO THIS...THE
PRECIPITATION CHANCES WERE REMOVED FROM THE FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 103 PM CDT THU SEP 26 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. HIGH
PRESSURE WILL BE IN PLACE OVER THE EASTERN GREAT LAKES AS TROUGH
OF LOW PRESSURE DEEPENS OVER THE NORTHERN AND CENTRAL
PLAINS...PLACING THE UPPER MISSISSIPPI RIVE VALLEY IN A TIGHT
PRESSURE GRADIENT. PLAN ON BREEZY SOUTH/SOUTHEAST WINDS AT 15 TO 17
KTS. KLSE WILL DECOUPLE LATE THIS EVENING...LEADING TO LOW LEVEL
WIND SHEAR. WINDS INCREASE TO AROUND 40 KTS AT 1KFT. HAVE INCLUDED
LLWS IN THE TAF AT KLSE FROM 05Z THROUGH 14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1135 AM CDT THU SEP 26 2013
.UPDATE...CLEAR SKIES ARE EXPECTED FOR MOST OF THE AREA TODAY.
HOWEVER...SOME CU HAS DEVELOPED IN THE EAST...ESPECIALLY NEAR
SHEBOYGAN...WHERE DEW POINTS ARE HIGHER AND SOUTHEAST WINDS OFF
THE LAKE ARE PROVIDING CONVERGENCE. THE CLOUDS ARE EXPECTED TO
DISSIPATE...AS MIXING OCCURS AND RAP FORECAST SOUNDINGS SHOW
ABUNDANT DRY AIR AND SUBSIDENCE AROUND 850 MB BY EARLY AFTERNOON.
TEMPERATURES MAY GET A FEW DEGREES WARMER THIS AFTERNOON THAN
PLANNED. 925 MB TEMPS RANGE FROM 17 TO 20 C...WHICH WOULD GIVE US
HIGHS IN THE MID TO UPPER 70S. WHILE TEMPERATURES ALONG THE LAKE
ARE RISING QUICKLY...THEY ARE EXPECTED TO MODERATE THIS AFTERNOON
THANKS TO THE ONSHORE WIND. HIGH TEMPERATURES ARE NOW EXPECTED TO
RANGE FROM THE LOWER 70S IN THE EAST...TO THE UPPER 70S IN THE
WEST.
MEB
&&
.AVIATION/18Z TAFS/...HIGH PRESSURE WILL REMAIN WELL EAST OF THE
REGION THROUGH FRIDAY. LIGHT SOUTHEAST WINDS ARE EXPECTED UNTIL
SUNSET...WITH A FEW DIURNAL CUMULUS CLOUDS AT THE EASTERN SITES.
LIGHT SOUTHEAST WINDS SHOULD LINGER THROUGH TONIGHT AND EARLY
FRIDAY MORNING...THOUGH COULD SEE LIGHT/VARIABLE OR CALM WINDS AT
TIMES. PATCHY FOG WITH MVFR VISIBILITIES ARE EXPECTED AT SITES
EXCEPT MILWAUKEE BETWEEN 08Z AND 13Z FRIDAY.
LIGHT TO MODERATE SOUTHEAST WINDS ARE EXPECTED FOR THE REST OF
FRIDAY...WITH GUSTS TO 17 KNOTS AT TIMES. SCATTERED DIURNAL
CUMULUS ARE POSSIBLE DURING THE LATE MORNING AND EARLY
AFTERNOON...ESPECIALLY AT THE EASTERN SITES.
WOOD
&&
.MARINE...WINDS AND WAVES MAY REACH SMALL CRAFT ADVISORY LEVELS
MAINLY ON SATURDAY ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. A
TIGHT PRESSURE GRADIENT AHEAD OF A COLD FRONT SHOULD BRING GUSTY
SOUTH/SOUTHEAST WINDS UP TO 25 KNOTS DURING THIS TIME. THESE WINDS
SHOULD GENERATE HIGH WAVES OF 3 TO 6 FEET.
WOOD
&&
.PREV DISCUSSION... /ISSUED 318 AM CDT THU SEP 26 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH
500/250 MB RIDGE WILL BUILDS ACROSS EASTERN WISCONSIN AND THEN OVER
THE WESTERN GREAT LAKES LATE TONIGHT WITH DEVELOPING SOUTHWEST FLOW
OVER THE UPPER MISSISSIPPI VALLEY.
THE 850/700/500 MB LAYERS REMAIN DRY ALTHOUGH 850 MB RH INCREASES
TOWARD THE MISSISSIPPI VALLEY BY TONIGHT AS A STRONG SOUTH LOW LEVEL
EXTENDS FROM WESTERN KANSAS TO MINNESOTA. HOWEVER THE RIDGE WILL
REMAIN IN PLACE OVER THE GREAT LAKES.
ONLY A SLIGHT INCREASE IN 850/700 MB TEMPERATURES LATER TODAY.
THE SURFACE RIDGE WILL REMAIN OVER THE GREAT LAKES BUT THE LIGHT
EAST WINDS WILL BECOME MORE SOUTHEAST TONIGHT AND INCREASE SLIGHTLY
OVER SOUTH CENTRAL WISCONSIN.
MAIN ISSUE WILL BE THE VERY SHORT TERM WITH GOOD LONG WAVE
RADIATIONAL CONDITIONS DURING THE EARLY MORNING HOURS. VERY LIGHT
EAST FLOW SHOULD RESULT IN AREAS OF DENSE FOG. HOWEVER BOUNDARY
LAYER WINDS A BIT STRONGER THAN LAST NIGHT. STILL...FAIRLY SIMILAR
SETUP TO LAST NIGHT WHICH HAD DENSE FOG VISIBILITIES BOUNCING UP AND
DOWN IN MANY LOCATIONS.
RADIATIONAL CONDITIONS NOT QUITE AS GOOD LATE TONIGHT BUT AREAS OF
FOG STILL EXPECTED ESPECIALLY EAST.
FRIDAY - CONFIDENCE...HIGH
WARM DAY WITH SOUTHERLY FLOW AHEAD OF THE APPROACHING PLAINS COLD
FRONT. MODELS AGREE ON 925 TEMPS 18-20C FROM EAST TO WEST ACROSS THE
CWA. DYNAMICS AND FRONTAL FORCING REMAIN ACROSS MN AND IA.
SATURDAY AND SATURDAY NIGHT - CONFIDENCE...MEDIUM
LOW LEVEL THERMAL RIDGE ORIENTED ACROSS THE STATE AT 18Z. FRONT THEN
SWEEPS THROUGH DURING THE AFTERNOON EXITING THE SOUTHEAST AROUND
00Z. CWASP INTO THE 60S BUT BUFKIT IS REALLY SHOWING LITTLE IN THE
WAY OF INSTABILITY. WAS TEMPTED TO REMOVE THUNDER ALL TOGETHER BUT
LEFT THE TOKEN ISOLATED IN THE GRIDS. FIRST AND MORE SIGNIFICANT
SHORTWAVE ALIGNED WITH LOW LEVEL FORCING FEATURES WHISKS EAST THOUGH
LAGS SPEED OF SURFACE/850 FORCING. 12Z AND 00Z ECMWF NOT ADDING
GREAT CONFIDENCE TO GOING DRY AFTER 6Z SATURDAY NIGHT SO LINGERED A
HIGHER CHANCES IN THE EAST AND TO MESH BETTER WITH SURROUNDING
OFFICES. OTHER MODELS MORE PROGRESSIVE AND IMPLY THINGS DRY OUT
AFTER 6Z. SO ADDITIONAL REFINEMENT OF THE TIMING LIKELY AS MODELS
COME INTO BETTER AGREEMENT.
SUNDAY THROUGH WEDNESDAY - CONFIDENCE...MEDIUM
OVERALL A WARM PERIOD. QUICK HITTING THERMAL TROUGH IN THE WAKE OF
THE FRONTAL BOUNDARY. HIGH SHIFTS EAST MONDAY AND RETURN FLOW SETS
UP WITH MODIFYING 925 TEMPS. GFS MORE AGGRESSIVE WITH WEDNESDAY
PRECIP THOUGH MAIN SUPPORT FOR PRECIP LOOKS TO BE WELL NORTH WITH
THE STRONGER WESTERLIES. SO PER COLLAB WITH SURROUNDING
OFFICES...WILL KEEP FORECAST DRY GIVEN THE NOD TO THE DRY LOOK OF
THE ECMWF.
AVIATION/12Z TAFS/...MVFR/IFR FOG EARLY THIS MORNING WITH SOME LIFR
FOG ESPECIALLY IN LOW AREAS AND RIVER VALLEYS. FOG WILL DISSIPATE
DURING THE MID TO LATE MORNING. LESS MOISTURE MOISTURE BELOW THE INVERSION
AROUND 3 TO 4 THSD FT TO GENERATE FEW FAIR WEATHER CUMULUS WITH VFR
CONDITIONS BY AFTERNOON. SURFACE RIDGE WILL REMAIN OVER THE GREAT
LAKES.
VFR CONDITIONS DURING THE EVENING. THEN PATCHY IFR VSBYS AGAIN LATE
TONIGHT WITH FOG...ESPECIALLY EAST IN LOW AREAS AND RIVER VALLEYS.
MARINE...WINDS AND WAVES MAY REACH SMALL CRAFT ADVISORY LEVELS MAINLY
ON SATURDAY ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. A TIGHT
PRESSURE GRADIENT AHEAD OF A COLD FRONT SHOULD BRING GUSTY SOUTH/SOUTHEAST
WINDS UP TO 25 KNOTS DURING THIS TIME. THESE WINDS SHOULD GENERATE
HIGH WAVES OF 3 TO 6 FEET.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MEB/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
FRIDAY THROUGH WEDNESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
623 AM CDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT THU SEP 26 2013
AT 3 AM...A 1020 MB HIGH WAS CENTERED NORTH OF LAKE HURON.
EASTERLY WINDS ON THE SOUTHERN PERIPHERY OF THIS HIGH CONTINUES TO
BRING LOWER AND MID 40 DEW POINTS INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN. THE COMBINATION OF THESE DEW POINTS ALONG WITH CLEAR
SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES THESE AREAS TO COOL
INTO THE LOWER AND MID 40S. WITH THESE TEMPERATURES COOLER THAN
THE WATER TEMPERATURES...STEAM FOG HAS DEVELOPED IN THIS AREA.
THERE ARE EVEN A FEW REPORTS OF DENSE FOG AT VOLK FIELD AND WAUTOMA.
WITH BUFKIT RAP SOUNDINGS CONTINUING TO SHOW THAT THE WINDS BELOW
900 MB WILL BE INCREASING TO AROUND 10 KNOTS BY SUNRISE...NOT
EXPECTING THIS FOG TO BECOME AS WIDESPREAD AS WEDNESDAY MORNING.
HOWEVER WITH THIS SAID...WE ARE STILL CONSIDERING A DENSE FOG
ADVISORY IN ADAMS AND JUNEAU COUNTIES IN CENTRAL WISCONSIN.
SHERIFF DEPARTMENTS IN BOTH OF THESE COUNTIES ARE REPORTING
PATCHY DENSE FOG. THE RAP WOULD SUGGEST THAT THE LOW LEVEL
MOISTURE WILL INCREASE THROUGH THE REMAINDER OF THIS MORNING.
MEANWHILE NAM/WRF SHOWS THAT THIS LOW LEVEL MOISTURE MIXES OUT BY
26.14Z.
FOR TODAY...HIGH PRESSURE WILL PROVIDE ANOTHER SUNNY DAY ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY. AS DIURNAL HEATING MIXES OUT
THE NOCTURNAL INVERSION THIS MORNING...EXPECT WIND GUSTS TO CLIMB
INTO THE 15 TO 30 MPH BETWEEN 10 AM AND NOON...AND THEN CONTINUE
THROUGH THE AFTERNOON. LIKE YESTERDAY...IT LOOKS LIKE THE AREA
WILL MIX TO AROUND 875 MB. THIS WILL YIELD TEMPERATURES IN THE
LOWER TO MID 70S NORTH OF INTERSTATE 94...AND FROM THE MID 70S TO
AROUND 80 ACROSS THE REMAINDER OF THE AREA.
FOR TONIGHT...THE CENTER OF SURFACE HIGH WILL DRIFT EAST INTO
QUEBEC. THIS WILL ALLOW THE COLD FRONT...CURRENTLY LOCATED OVER
THE CENTRAL DAKOTAS...TO MOVE EAST INTO WESTERN AND NORTHERN
MINNESOTA. AS THIS OCCURS...SOME MOISTURE BETWEEN 600 AND 700 MB
WILL MOVE EAST INTO THE FORECAST AFTER AFTER 27.08Z. THE NOCTURNAL
INVERSION WILL QUICKLY THIS EVENING WITH THE LOSS OF DIURNAL
HEATING. AS THIS OCCURS...THE WIND GUSTS WILL DIMINISH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 321 AM CDT THU SEP 26 2013
FROM FRIDAY AFTERNOON INTO FRIDAY NIGHT...THE 26.00Z MODELS ARE
IN VERY GOOD AGREEMENT THAT THE COLD FRONT WILL MOVE EAST INTO
WESTERN MINNESOTA DURING THE AFTERNOON AND EVENING...AND THEN IT
STALLS ITS EASTWARD PROGRESS ON FRIDAY NIGHT AS A SURFACE LOW
MOVES NORTH ALONG IT. WITH SOUNDINGS CONTINUING TO SHOW CAPPING
BETWEEN 800 AND 650 MBS AND DRY AIR AHEAD OF THIS FRONT...NOT
EXPECTING ANY PRECIPITATION TO OCCUR AHEAD OF IT....THUS KEPT THE
FORECAST DRY.
FROM SATURDAY INTO SATURDAY EVENING...THE MODELS CONTINUE TO SHOW
THAT THE SURFACE COLD FRONT AND SHORT WAVE TROUGH WILL MOVE
QUICKLY EAST ACROSS THE AREA. LIKE THE PAST DAYS...THE 0-6 KM
SHEAR REMAINS ABOVE 40 KNOTS ALONG AND IN THE WAKE OF THE FRONT.
HOWEVER THE ML CAPES REMAIN GENERALLY LESS THAN 100 J/KG...SO
STILL NOT CONCERNED THAT THE AREA WILL EXPERIENCE ANY SEVERE
WEATHER. JUST TOO LITTLE INSTABILITY FOR THE AMOUNT SHEAR.
OVERALL...ACTUALLY THINK THAT OUR BEST CHANCE OF THUNDER WILL
ACTUALLY COME FROM MORE SLANTWISE THAN UPRIGHT CONVECTION. DUE TO
THE CONSISTENCY OF THE TIMING WITH THE FRONTOGENESIS...RAISED THE
PRECIPITATION CHANCES INTO THE 75 TO 84 PERCENT RANGE. THINKING
WITH THE SPEED OF THE SHORT WAVE TROUGH AND FRONT THAT THE
PRECIPITATION WILL LIKELY ONLY LAST 2 TO 4 HOURS IN ANY LOCATION.
FROM TUESDAY INTO WEDNESDAY...THE MODELS ARE NOW SHOWING THAT THE
SHORT WAVE WILL PASS WELL NORTH OF THE AREA. DUE TO THIS...THE
PRECIPITATION CHANCES WERE REMOVED FROM THE FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 623 AM CDT THU SEP 26 2013
THE MAIN FOCUS IS ON THE POTENTIAL FOR FOG THIS MORNING FOLLOWED
BY HOW WINDY IT WILL BE THIS AFTERNOON. DENSE FOG HAS FORMED
ACROSS THE EASTERN HALF OF WISCONSIN AND IS TRYING TO SPREAD WEST
WARD TOWARD LSE. LOW LEVEL WINDS APPEAR TO BE STRONGEST THERE AND
SHOULD KEEP CONDITIONS VFR OR MVFR AT THE WORST. WITH THIS
TIGHTENING PRESSURE GRADIENT EXPECTED TODAY ACROSS THE
REGION...WINDS WILL QUICKLY INCREASE LATER THIS MORNING ON INTO
THE AFTERNOON. SUSTAINED SOUTHEAST WINDS OF 12-18KTS WITH GUSTS UP
TO 26KTS ARE FORECAST THROUGH THE AFTERNOON BEFORE DIMINISHING
THIS EVENING. SKIES WILL MAINLY BE CLEAR THOUGH SOME SCT-BKN 4KFT
STRATOCUMULUS COMING OUT OF IOWA MAY LINGER FOR MUCH OF THE DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 AM CDT THU SEP 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT THU SEP 26 2013
AT 3 AM...A 1020 MB HIGH WAS CENTERED NORTH OF LAKE HURON.
EASTERLY WINDS ON THE SOUTHERN PERIPHERY OF THIS HIGH CONTINUES TO
BRING LOWER AND MID 40 DEW POINTS INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN. THE COMBINATION OF THESE DEW POINTS ALONG WITH CLEAR
SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES THESE AREAS TO COOL
INTO THE LOWER AND MID 40S. WITH THESE TEMPERATURES COOLER THAN
THE WATER TEMPERATURES...STEAM FOG HAS DEVELOPED IN THIS AREA.
THERE ARE EVEN A FEW REPORTS OF DENSE FOG AT VOLK FIELD AND WAUTOMA.
WITH BUFKIT RAP SOUNDINGS CONTINUING TO SHOW THAT THE WINDS BELOW
900 MB WILL BE INCREASING TO AROUND 10 KNOTS BY SUNRISE...NOT
EXPECTING THIS FOG TO BECOME AS WIDESPREAD AS WEDNESDAY MORNING.
HOWEVER WITH THIS SAID...WE ARE STILL CONSIDERING A DENSE FOG
ADVISORY IN ADAMS AND JUNEAU COUNTIES IN CENTRAL WISCONSIN.
SHERIFF DEPARTMENTS IN BOTH OF THESE COUNTIES ARE REPORTING
PATCHY DENSE FOG. THE RAP WOULD SUGGEST THAT THE LOW LEVEL
MOISTURE WILL INCREASE THROUGH THE REMAINDER OF THIS MORNING.
MEANWHILE NAM/WRF SHOWS THAT THIS LOW LEVEL MOISTURE MIXES OUT BY
26.14Z.
FOR TODAY...HIGH PRESSURE WILL PROVIDE ANOTHER SUNNY DAY ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY. AS DIURNAL HEATING MIXES OUT
THE NOCTURNAL INVERSION THIS MORNING...EXPECT WIND GUSTS TO CLIMB
INTO THE 15 TO 30 MPH BETWEEN 10 AM AND NOON...AND THEN CONTINUE
THROUGH THE AFTERNOON. LIKE YESTERDAY...IT LOOKS LIKE THE AREA
WILL MIX TO AROUND 875 MB. THIS WILL YIELD TEMPERATURES IN THE
LOWER TO MID 70S NORTH OF INTERSTATE 94...AND FROM THE MID 70S TO
AROUND 80 ACROSS THE REMAINDER OF THE AREA.
FOR TONIGHT...THE CENTER OF SURFACE HIGH WILL DRIFT EAST INTO
QUEBEC. THIS WILL ALLOW THE COLD FRONT...CURRENTLY LOCATED OVER
THE CENTRAL DAKOTAS...TO MOVE EAST INTO WESTERN AND NORTHERN
MINNESOTA. AS THIS OCCURS...SOME MOISTURE BETWEEN 600 AND 700 MB
WILL MOVE EAST INTO THE FORECAST AFTER AFTER 27.08Z. THE NOCTURNAL
INVERSION WILL QUICKLY THIS EVENING WITH THE LOSS OF DIURNAL
HEATING. AS THIS OCCURS...THE WIND GUSTS WILL DIMINISH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 321 AM CDT THU SEP 26 2013
FROM FRIDAY AFTERNOON INTO FRIDAY NIGHT...THE 26.00Z MODELS ARE
IN VERY GOOD AGREEMENT THAT THE COLD FRONT WILL MOVE EAST INTO
WESTERN MINNESOTA DURING THE AFTERNOON AND EVENING...AND THEN IT
STALLS ITS EASTWARD PROGRESS ON FRIDAY NIGHT AS A SURFACE LOW
MOVES NORTH ALONG IT. WITH SOUNDINGS CONTINUING TO SHOW CAPPING
BETWEEN 800 AND 650 MBS AND DRY AIR AHEAD OF THIS FRONT...NOT
EXPECTING ANY PRECIPITATION TO OCCUR AHEAD OF IT....THUS KEPT THE
FORECAST DRY.
FROM SATURDAY INTO SATURDAY EVENING...THE MODELS CONTINUE TO SHOW
THAT THE SURFACE COLD FRONT AND SHORT WAVE TROUGH WILL MOVE
QUICKLY EAST ACROSS THE AREA. LIKE THE PAST DAYS...THE 0-6 KM
SHEAR REMAINS ABOVE 40 KNOTS ALONG AND IN THE WAKE OF THE FRONT.
HOWEVER THE ML CAPES REMAIN GENERALLY LESS THAN 100 J/KG...SO
STILL NOT CONCERNED THAT THE AREA WILL EXPERIENCE ANY SEVERE
WEATHER. JUST TOO LITTLE INSTABILITY FOR THE AMOUNT SHEAR.
OVERALL...ACTUALLY THINK THAT OUR BEST CHANCE OF THUNDER WILL
ACTUALLY COME FROM MORE SLANTWISE THAN UPRIGHT CONVECTION. DUE TO
THE CONSISTENCY OF THE TIMING WITH THE FRONTOGENESIS...RAISED THE
PRECIPITATION CHANCES INTO THE 75 TO 84 PERCENT RANGE. THINKING
WITH THE SPEED OF THE SHORT WAVE TROUGH AND FRONT THAT THE
PRECIPITATION WILL LIKELY ONLY LAST 2 TO 4 HOURS IN ANY LOCATION.
FROM TUESDAY INTO WEDNESDAY...THE MODELS ARE NOW SHOWING THAT THE
SHORT WAVE WILL PASS WELL NORTH OF THE AREA. DUE TO THIS...THE
PRECIPITATION CHANCES WERE REMOVED FROM THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM CDT WED SEP 25 2013
THE 500 MB RIDGE AXIS HANGS ACROSS THE REGION OVERNIGHT...WHILE THE
SFC HIGH HOVERS OVER THE GREAT LAKES. WINDS HAVEN/T DECOUPLED IN THE
VALLEY AT KLSE...ALTHOUGH STILL ANTICIPATE THEY WILL LIGHTEN UP BY A
FEW MORE KTS. THAT SAID...KRST REMAINS IN THE 8-10 KT RANGE WHILE
WINDS INCREASE SEVERAL KNOTS MORE BY 200 FT. THIS NEAR SFC STIRRING
WILL MAKE IT DIFFICULT FOR RIVER VALLEY FOG TO SPREAD ACROSS
KLSE...IF IT WOULD DEVELOP. KLSE T/TD SPREAD AT 03Z WAS 8 F WITH 7
KT WINDS...NOT FAVORABLE FOR SUB 1/2SM. IF WINDS KEEP UP...MVFR BR
IS ALSO UNLIKELY. FOG DID NOT FORM IN THE PRESSURE GRADIENT THIS
MORNING...AND WITH THAT GRADIENT SHIFTED OVER KRST/KLSE...WILL STAY
WITH THE NON-FOG FORECAST FOR EARLY THU MORNING.
THE HIGH WILL CONTINUE TO EASE EAST THURSDAY...WITH A TIGHTENING
PRESSURE GRADIENT ACROSS THE REGION. WINDS WILL BE ON THE INCREASE
FROM THE SOUTH/SOUTHEAST AS A RESULT...GUSTY FOR THE LATE
MORNING/AFTERNOON HOURS.
ASIDE FROM ANY POTENTIAL FOR FOG OVERNIGHT...VFR CONDITIONS WILL
PERSIST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1149 PM MDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 1140 PM MDT FRI SEP 27 2013
JUST COMPLETED AN UPDATE. MAIN CHANGES WERE FIRST TO CANCEL THE
WIND ADVISORY AND TO ADJUST PRECIPITATION CHANCES. GRADIENT IS
BEGINNING TO DECREASE WITH THE 3 HOUR PRESSURE RISE MAX PUSHING
AWAY FROM THE AREA. BROKEN LINE OF THUNDERSTORMS OVER THE EASTERN
PORTION OF THE AREA PUSHING STEADILY EAST. ISOLATED RAIN SHOWERS
OVER THE WEST WILL BEGIN TO END AS WELL. OVERNIGHT TEMPERATURES
LOOKING ON TRACK WITH UPPER 30S EXPECTED IN THE WESTERN PORTION OF
THE AREA.
UPDATE ISSUED AT 801 PM MDT FRI SEP 27 2013
JUST COMPLETED AN UPDATE. OVERALL THE FORECAST IS IN PRETTY GOOD
SHAPE SO JUST MADE SOME ADJUSTMENTS BASED ON RECENT TRENDS...
OBSERVATIONS...SATELLITE AND RADAR. MAIN BAND OF INSTABILITY AND
THUNDERSTORMS IS NOW OVER THE CENTRAL PORTION OF THE AREA. HIGHEST
CHANCE OF PRECIPITATION AND INSTABILITY IS IN THE EASTERN HALF.
MAIN UPPER TROUGH AND DECENT AMOUNT OF LIFT STILL TO OUR WEST. SO
SHOULD STILL SEE A DECENT CHANCE IN THE WESTERN HALF OF THE AREA
BUT WILL BE PRIMARILY SHOWERS WITH EMBEDDED THUNDERSTORMS. LEFT
THE PRECIPITATION FORECAST ALONE AFTER 06Z SINCE IT LOOKS GOOD COMPARED
TO REALITY.
HARD TO TELL EXACTLY WHERE THE FRONT IS DUE TO THE THUNDERSTORM
OUTFLOW. BELIEVE IT IS STILL MOSTLY TO THE NORTHWEST OF US. BECAUSE
OF THE OUTFLOW...TEMPERATURES HAVE DROPPED PRETTY FAST ALREADY. DO
EXPECT WIND TO STAY UP AND NOT LET THE TEMPERATURES DROP TOO RAPIDLY.
SO DID ADJUST OVERNIGHT MINS DOWN A FEW DEGREES. AT THIS TIME...UPPER
30S WILL STILL BE POSSIBLE IN THE FAR WEST PORTION OF THE AREA.
WILL CONTINUE TO MONITOR THE WIND AND TEMPERATURE TRENDS. IF WINDS
DROP OFF MORE THAN EXPECTED THEN WILL NEED TO ADJUST MINS DOWN
SOME MORE.
WILL BE KEEPING THE WIND ADVISORY GOING AT THIS TIME. CURRENT
MESOSCALE GUIDANCE WOULD INDICATE WINDS BEHIND THE FRONT MAY NOT
BE AS STRONG AS PREVIOUS INDICATED. HOWEVER...WILL CONTINUE TO
WATCH TRENDS AND LET 00Z GUIDANCE ROLL IN AND ASSESS ONCE AGAIN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1230 PM MDT FRI SEP 27 2013
AS OF NOON MDT/1PM CDT...WV IMAGERY AND RAP H5 ANALYSIS SHOW
POSITIVELY TITLED TROUGH EXTENDING FROM NORTHERN ROCKIES ACROSS
THE GREAT BASIN...WITH ITS BASE NEAR THE BAJA PENINSULA. SW FLOW
IS IN PLACE ACROSS THE PLAINS WITH MID LEVEL MOISTURE PLUME
EXTENDING FROM THE PACIFIC OCEAN AND INTO WESTERN KANSAS OVER OUR
CWA. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING FROM
ABOUT LIMON COLORADO...TO GOODLAND KS...AND NORTH INTO CENTRAL
NEBRASKA. LIGHT TO MODERATE SHOWERS HAVE DEVELOPED ALONG THE
LEADING EDGE OF THIS FRONT...WITH RECENT RADAR RETURNS SHOWING AN
INCREASE IN INTENSITY AND COVERAGE.
GUIDANCE CONTINUES TO INDICATE THIS FRONT LIFTING LATER THIS
AFTERNOON WITH INSTABILITY INCREASING EAST OF THE FRONT OVER
WESTERN/CENTRAL KANSAS. FORECAST SEEMS TO BE ON TRACK REGARDING
COVERAGE...WITH LIGHT TO MODERATE SHOWERS AND ISOLATED
THUNDERSTORMS LIKELY THIS AFTERNOON AND EVENING. HOWEVER THERE HAS
BEEN LITTLE INDICATION OF FRONT LIFTING SO FAR...AND UNTIL IT
DOES THUNDERSTORM COVERAGE (AND SEVERE THREAT) IS IN QUESTION.
LATEST RAP SHOWS 600-900 J/KG OF MUCAPE BY AROUND 00Z IN THE EAST
WHICH ISNT PARTICULARLY IMPRESSIVE...THOUGH IT IS WORTH MENTIONING
THAT THE NAM HAS OVER 1500 J/KG OF MU CAPE IN A SIMILAR AREA. THE
DIFFERENCE SEEMS TO BE TIMING/POSITION OF FRONT WITH NAM
QUICKER/FURTHER NORTH. SHEER IS VERY IMPRESSIVE WITH 0-6KM BULK
SHEER 50KT TO 80KT FROM THE EAST TO THE WEST...AND INCREASING
EFFECTIVE SHEER 40-50KT. IF WE CAN GET A STRONG ENOUGH UPDRAFT
(INSTABILITY DEPENDED) IT COULD QUICKLY BECOME SEVERE CONSIDERING
THE SHEER PROFILES. LCLS ARE STILL ADVERTISED AROUND 9-10KFT
WHICH IS PRETTY HIGH FOR A WIDESPREAD TORNADO THREAT...SO
WIND/HAIL/HEAVY RAIN CONTINUE TO BE THE PRIMARY CONCERNS THIS
AFTERNOON AND EVENING.
VERY DRY/SUBSIDENT AIR MASS WILL BUILD IN FROM THE WEST BEHIND A
COLD FRONT THIS EVENING...AND MODELS SUPPORT SHOWERS/THUNDERSTORMS
QUICKLY ENDING FROM WEST TO EAST IN THE 03-06Z PERIOD. I KEPT SOME
CHANCE POPS LINGERING THROUGH 09Z IN THE EAST TO ACCOUNT FOR A
SLOWER FRONTAL EXIT FOR THOSE LOCATIONS...HOWEVER THIS APPEARS TO
BE MAINLY A AFTERNOON/EVENING EVENT. PRECIP AMOUNTS COULD BE VERY
IMPRESSIVE CONSIDERING THE AMOUNT OF FORCING/MOISTURE
ADVERTISED...AND MODEL QPF FORECASTS CONTINUE TO SUPPORT RAINFALL
AMOUNTS FROM ONE QUARTER OF AN INCH IN THE WEST TO NEAR ONE INCH
IN THE NORTHEAST. WITH POSSIBLE TRAINING/BACK BUILDING OF
SHOWERS/THUNDERSTORMS WE WILL NEED TO MONITOR FOR POSSIBLE FLASH
FLOODING.
REGARDING WIND ADVISORY...THERE SHOULD BE A SHARP INCREASE IN
WINDS IMMEDIATELY BEHIND THE COLD FRONT THIS EVENING. LATEST MODELS
HAVE DECREASED THE WINDS ALOFT SOME FROM PREVIOUS GUIDANCE...AND
SPED UP THE FRONTAL PASSAGE. IM STILL CONFIDENT WE WILL SEE A
BRIEF PERIOD OF NEAR ADVISORY TO ABOVE ADVISORY WIND GUSTS THIS
EVENING THROUGH AROUND MIDNIGHT IN THE EAST...SO I DIDNT SEE A
REASON TO CANCEL THE WIND ADVISORY. IT CURRENTLY RUNS THROUGH
12Z...WHICH MANY BE TOO LONG...HOWEVER IT DOES COVER THE
POSSIBILITY OF A SLOWER FROPA IN THE EAST.
WITH CLEARING SKIES AND A VERY COOL/DRY AIR MASS ADVECTING IN FROM
THE WEST AFTER MIDNIGHT WE WILL LIKELY SEE SOME OF THE COOLER TEMPS
SO FAR THIS MONTH. IF WINDS DECREASE BELOW 10KT (WHICH IS NOT
CURRENTLY EXPECTED) WE COULD COOL TO THE LOW TO MID 30S IN THE
WEST WHICH WOULD PUT US WITHIN FROST ADVISORY CRITERIA
(CONSIDERING TD VALUES AROUND 33F ADVERTISED BY SHORT RANGE MODEL
CONSENSUS). LOWS ARE CURRENTLY EXPECTED TO BE FROM THE UPPER 30S
IN THE WEST TO NEAR 50 IN THE EAST...SO NO ADVISORY IS CURRENTLY
ANTICIPATED.
.LONG TERM...(TOMORROW THROUGH FRIDAY)
ISSUED AT 1237 PM MDT FRI SEP 27 2013
QUIET WEATHER IS EXPECTED THROUGH AT LEAST MID WEEK AS ZONAL FLOW
BECOMES ESTABLISHED ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE
WILL BE SOME EMBEDDED WEAK DISTURBANCES...BUT THE MAIN STORM TRACK
WILL SHIFT NORTHWARD WITH TIME AND LOW LEVEL MOISTURE WILL BE VERY
LIMITED. THE NEXT FRONTAL PASSAGE MAY OCCUR WEDNESDAY NIGHT AS THE
UPPER FLOW BECOMES MORE SOUTHWEST AHEAD OF A SHORTWAVE TROUGH IN
THE NORTHERN ROCKIES. MODELS ARE IN VERY POOR AGREEMENT AT THIS
TIME...THE ECMWF HAS THE FRONT IN THE DAKOTAS WHILE THE GFS PUSHES
IT THROUGH THE LOCAL AREA WITH A CHANCE OF PRECIPITATION...SO
PREFER TO WAIT FOR BETTER MODEL CONSISTENCY BEFORE COMMITTING TO
POPS. FOR THE LATER PART OF THE WEEK...MODEL CONSISTENCY BECOMES
EVEN WORSE WITH THE ECMWF AND GFS COMPLETELY OUT OF PHASE IN THEIR
UPPER PATTERNS BY FRIDAY. GIVEN THE LOW CONFIDENCE...FORECAST WILL
HEDGE TOWARD NEAR NORMAL TEMPERATURES AND NO MENTION OF PRECIPITATION
AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1140 PM MDT FRI SEP 27 2013
BULK OF PRECIPITATION IS TO THE EAST OF BOTH TAF SITES. VERY LOW
CHANCE OF RAIN SHOWERS AFFECTING THE KMCK SITE WITH NO VISIBILITY
RESTRICTION EXPECTED. MVFR CEILINGS AT KMCK SHOULD END BY 09Z WITH
VFR CONDITIONS EXPECTED THERE AFTER THAT. VFR CONDITIONS EXPECTED
AT KGLD. GUSTY WINDS WILL END BY 09Z AT BOTH SITES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...024
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1156 PM CDT Fri Sep 27 2013
.SHORT TERM...(This Evening through Saturday)
Issued at 252 PM CDT FRI SEP 27 2013
Tonight through Saturday...
Analysis of the water vapor imagery at 19z depicts the potent
shortwave trough axis rotating through southern Wyoming. An embedded
wave and mid level jet streak within the mean flow was lifting
northward into western Kansas. Looking at the surface, the potent
cold front was oriented southwest to northeast from eastern Colorado
through northwest Kansas, through central and northern Nebraska.
Observations noted 30 degree F temp differences between the
boundaries with upper 40s in northeast Colorado. The surface trough
undergoing lee cyclogenesis over southern Colorado continued to
provide strong southerly winds between 15 and 25 mph with gusts over
30 mph during the current peak heating hours. In turn gulf moisture
streaming northward in advance of the sfc trough has brought
dewpoint temperatures into the low 60s. The aforementioned mid level
wave in combination with the surface front has continued to generate
elevated showers lifting northward across western Kansas.
As the upper wave lifts northeastward into the northern plains,
expect the lee surface trough and frontal boundary to quickly usher
eastward towards northeast Kansas. A line of numerous showers and
thunderstorms are likely to develop in vicinity and along the
boundary during the evening and overnight hours. Consistency between
the latest runs of the 3 km HRRR peg the edge of the precip and
front entering north central areas after 07z, impacting much of east
central areas(including Topeka) after 09z. While the highest
probabilities of severe storms reside towards western and central
Kansas, expect the instability gradient to drop steadily eastward
with only a few hundred j/kg of ML cape over north central areas
around 06z. However, strong effective shear values over 50 kts may
still allow for strong gusty winds from 40 to 50 mph. Locally heavy
rain is likely with the heavier showers as pwat values range from
1.25 to 1.9 inches. QPF values did not deviate much from previous
forecast based on fast track of the front ranging from 0.30 to three
quarters of an inch. Precipitation is expected to end Saturday
afternoon with cloud cover quickly exiting southeast as a drier and
cooler airmass settles in.
Temperatures tonight depend on thickness of cloud cover and showers
with lowest readings over north central areas where cool advection
behind the front will be filtering southward. Further east, lows in
the upper 60s appear to be more common. Expect temps to hover in the
60s for much of Saturday afternoon before a gradual warmup as the
clouds thin, topping out in the low 70s. Northerly winds remain
gusty through the period as the h85 shortwave trough continues to
impact the region before exiting Saturday evening.
.LONG TERM...(Saturday Night through Friday)
Issued at 252 PM CDT FRI SEP 27 2013
As skies clear out and winds settle down behind the front on
Saturday night, overnight lows into Sunday morning are expected to
drop into the lower to middle 40s. Will need to monitor for fog
potential, but air mass is quite dry and therefore fog potential
could be limited to low spots. Sunday forecast to be sunny with
highs in the lower to middle 70s and light south winds. Lows
overnight into Monday should be a few degrees warmer as southerly
winds continue. Thermal ridge out ahead of the next approaching
trof expected to bring highs Monday through Wednesday back up
toward 80 and then lows only falling into the 50s to near 60 by
Thursday morning.
While the sensible weather forecast for Thurs/Fri remains similar
to that of mid week, the speed of an upper trof advancing eastward
into the plains will be the driver of true timing of rain chances
and colder air. Was backing off on progressive solutions as
several ensemble members along with the 00z ECMWF showing a slower
trend, however 12z runs are now coming in slightly faster. Opted
to keep slight chances for rain Thur/Fri, with timing chances too
uncertain to make large changes to a consensus forecast this far
out.
&&
.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1156 PM CDT FRI SEP 27 2013
For the 06z TAFs, southeasterly winds at around 10-12kts will
continue through the overnight hours. Main focus is on the timing of
the approaching cold front, which as of 05z was located over western
Kansas. Most of the precipitation is expected to be focused along and
behind this front, with short-range models showing showers and
possibly a few isolated thunderstorms moving into the TAF sites
between 09-11z. Post-frontal showers will continue through much of
the morning hours with conditions drying out by the afternoon. With
this precipitation, could see cigs drop down to MVFR conditions for
a few hours in the morning. With the frontal passage, winds will
veer to the northwest and persist through the remainder of the
period. However, these winds should become light by tonight.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Bowen
LONG TERM...67
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1147 PM CDT FRI SEP 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 330 PM CDT FRI SEP 27 2013
SATELLITE IMAGERY THIS AFTERNOON IS SHOWING LIFT AHEAD OF THE
ROCKIES WAVE BEGINNING TO INCREASE AS CLOUD TOPS BEGIN TO COOL FROM
NW KS UP INTO SE SODAK. THIS IS THE BEGINNINGS OF THE POST FRONTAL
BAND OF FGEN INDUCED PRECIP THAT ALL MODELS SHOW DEVELOPING THIS
EVENING...WEST OF THE MPX AREA. BESIDE THE COOLING CLOUD
TOPS...SATELLITE ALSO SHOWING CLEARING RAPIDLY MOVING NORTH ACROSS
MN AND WE HAVE REALLY SEEN WINDS/TEMPS RESPOND TO THE
CLEARING...WITH FAIRMONT HITTING 88 AT 3 PM...ALONG WITH GUSTS
ACROSS SOUTH CENTRAL MN ALSO APPROACHING 40 MPH.
BIGGEST CHANGE MADE TO THE FORECAST WAS TO SLOW DOWN THE ARRIVAL OF
PRECIP TONIGHT. THE REASON IS THAT THE FRONT AND ITS ASSOCIATED FGEN
BAND DO NOT LOOK TO MOVE EAST UNTIL THE UPPER WAVE BEGINS TO EJECT
ACROSS THE PLAINS...WHICH DOES NOT BEGIN TO HAPPEN UNTIL AFTER 6Z.
GIVEN STRONG FORCING ASSOCIATED WITH THIS WAVE...SEEING STRONG
AGREEMENT AMONG HIRES MODELS...WITH EVERYTHING FROM THE HOPWRF
MEMBERS TO YOUR SPC/NMM/ARW WRFS SHOWING RAIN NOT BEGINNING TO MOVE
INTO WRN MN UNTIL ALMOST 9Z. THOUGHT ORIENTATION OF INHERITED POPS
FOR TONIGHT THROUGH SATURDAY LOOKED GOOD...SO MAINTAINED THE LOOK OF
THE POP GRIDS...JUST SLOWED THINGS DOWN BY 3 OR 4 HOURS TODAY.
HAVE MAINTAINED SOME CHANCE POPS IN THE NW CWA BETWEEN 00Z AND 06Z
AS THE HRRR CONTINUES TO SHOW SCATTERED CONVECTION DEVELOPING ALONG
THE COLD FRONT BETWEEN 00Z AND 02Z...BUT THE MAIN SHOW PRECIPITATION
WISE IS COMING LATE TONIGHT. IF WE DO GET CONVECTION TO FIRE AS THE
HRRR SUGGESTS...DO NOT ANTICIPATE ANY OF IT WILL BE SEVERE THANKS TO
SBCAPES LESS THAN 1000 J/KG. WOULD NEED MORE ROBUST INSTABILITY TO
GET MUCH MORE OF A SEVERE THREAT.
FOR TONIGHT...WAS TEMPTED TO REMOVE ANY THUNDER MENTION FROM THE
FORECAST SINCE FOR THE MOST PART THIS WILL JUST BE RAIN. BUT WILL
LIKELY HAVE A FEW RUMBLES OF THUNDER AS THE BAND MOVES THROUGH...SO
MAINTAINED THE ISO THUNDER WORDING.
FOR QPF...MODEL CONSENSUS HAS REMAINED QUITE HIGH IN 0.3-0.5 INCHES
FALLING ACROSS MOST OF THE AREA...SO KEPT THE QPF FORECAST CLOSE TO
A WPC/MODEL BLEND.
FINALLY FOR TEMPERATURES...BEING OUT AHEAD OF THE FRONT WE WILL HAVE
ANOTHER MILD NIGHT...WITH MUCH OF THE AREA ONLY FALLING BACK INTO
THE MID 60S FOR LOWS...WHICH IS RIGHT ABOUT NORMAL...FOR HIGHS THIS
TIME OF YEAR! FOR SATURDAY...USED THE NAM TO RUN THE DIURNAL TREND
FOR TEMPERATURES...WHICH RESULTED IN FALLING TEMPERATURES DURING THE
MORNING AND AFTERNOON IN THE ERN CWA AS THE BAND OF RAIN MOVES FROM
ERN MN INTO WRN WI.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 PM CDT FRI SEP 27 2013
AFTER SATURDAY SYSTEM MOVES ACROSS THE UPPER MIDWEST...THE MEAN
FLOW AND ASSOCIATED MOISTURE AND SFC FEATURES WILL BE WELL INTO
CANADA LEADING TO A DRY PERIOD THRU THE MIDDLE OF NEXT WEEK.
OVER THE PAST WEEK OR TWO...THE PACIFIC NW HAS BEEN VERY WET DUE
TO A PERSISTENT ONSHORE FLOW WHICH IS EXPECTED THRU THE EARLY PART
OF NEXT WEEK. OUR REGION WILL HOLD ONTO A MORE FAST WEST TO EAST
FLOW...WITH THE CENTRAL U.S. AND THE SE MUCH WARMER AS AN UPPER
LEVEL RIDGE BEGINS TO BUILD. THE MEAN LONG WAVE TROUGH ACROSS
WESTERN PART OF NORTH AMERICA IS EXPECTED TO TRANSITION TO A WEAK
UPPER RIDGE /PACIFIC NW/...WHICH IS A DRY WEATHER PATTERN.
BETWEEN THE RIDGE IN THE SE...AND THE PACIFIC NW...THE LONG WAVE
TROUGH IS EXPECTED TO MOVE ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS BY LATE NEXT WEEK. BASICALLY THIS IS A WETTER PATTERN FOR
THE UPPER MIDWEST AS MOISTURE FROM THE GULF BEGINS TO INTERACT
WITH A POWERFUL JET STREAM PROGGED TO BE ACROSS THE NORTHERN U.S.
THE UPPER JET ALONE WILL LEAD TO A BETTER CHC OF CYCLOGENESIS
DEVELOPING IN THE PLAINS /INCREASING MOIST FROM THE GULF/ AND AN
INCREASE IN PRECIPITATION CHC/S. THE MAIN UNCERTAINTY IS TIMING OF
THIS PATTERN CHG...ESPECIALLY IN REGARDS TO SFC FEATURES. BOTH THE
GFS/EC HAVE A SIMILAR PATTERN LATE NEXT WEEK...BUT THE DIFFERENCES
ARISE IN THE AMPLIFICATION. THE GFS IS MORE AMPLIFIED...ESPECIALLY
BY FRIDAY WITH A CUT OFF SYSTEM ACROSS THE WESTERN GREAT LAKES.
THE EC IS MORE PROGRESSIVE...BUT HAS THE SAME LONG WAVE TROUGH IN
THE NORTHERN U.S. THE GFS ENSEMBLE MEAN OF THE 50H PATTERN SEEMS
TO BE MORE IN LINE OF A DEEPER TROUGH...AND BETTER UPPER LEVEL
FORCING FOR THE UPPER MIDWEST. WILL HOLD ONTO THE CHC/LIKELY POPS
FOR THU/FRI OF NEXT WEEK. HOWEVER...TRENDS OF THE MODELS WILL
DICTATE THE STRENGTH AND SPEED ONCE THE PATTERN BEGINS TO CHG
EARLY NEXT WEEK.
A FINAL NOTE...BOTH THE GFS/EC DOES SHOW A SIGNIFICANT COOL DOWN
ONCE THIS PATTERN DEVELOPS AND MOVES THRU THE WEEKEND OF OCTOBER
5TH. 85H TEMPS FRIDAY NIGHT ARE COLD ENOUGH FOR SNOW IN THE
ARROWHEAD OF MN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1125 PM CDT FRI SEP 27 2013
SHOWERS/THUNDER ON THE MN/DAKOTAS BORDER WEST OF KAXN AT 05Z.
APPEARS THIS FIRST WAVE WILL MISS KAXN. WEAK SURFACE LOW OVER
EASTERN NEBRASKA IS FORECAST LIFT NORTHEAST ALONG THE FRONT
OVERNIGHT...SLOWING THE FORWARD PROGRESS OF THE FRONT. THE LOW
SHOULD BE NORTHEAST OF KAXN THROUGH ABOUT 10Z. THE FRONT SHOULD
THEN MAKE EASTWARD PROGRESS TO KMSP AROUND 15Z AND INTO THE KEAU
AREA BY 20Z. CEILINGS FORECAST TO DROP TO AT LEAST MVFR WITH
PASSAGE OF THE FRONT. DID MENTION IFR AT KAXN...AFTER 11Z FOR. LOW
END MVFR EXPECTED WITH THE SHRA/RA AS IT MOVES EAST. GOOD FORCING
ALONG THE FRONT SO DO ANTICIPATE A FEW HOURS OF RAIN AT MOST LOCATIONS.
THUNDER THREAT TOO LOW TO INCLUDE AT TAFS. SHOULD CLEAR OUT BY LATE
AFTERNOON WEST AND EARLY EVENING IN THE EAST. SOME THREAT OF FOG
FORMING LATE...MAINLY IN WEST CENTRAL WISCONSIN. THIS SHOULD BE
AFTER 06Z.29 HOWEVER. SURFACE WINDS WILL INCREASE OUT AHEAD OF THE
FRONT EARLY...THEN BECOME W/NW WITH FROPA AND GUSTY FOR A TIME AS
WELL. SHOULD ALL DIMINISH BE 00Z.29.
KMSP...
SSE WINDS WILL PERSIST THIS MORNING...WITH SOME GUSTS NEAR 20KTS
AS SURFACE LOW TO THE SOUTHWEST LIFTS NORTHEAST ALONG THE FRONT.
FROPA AROUND 15Z. WINDS BECOMING WEST AND INCREASING WITH SOME
GUSTS 20-25KTS POSSIBLE IN THE AFTERNOON. EXPECT CEILINGS TO DROP OFF
TO MVFR RAPIDLY WITH -SHRA. SOME POTENTIAL OF LESS THAN 017 BUT
WILL MONITOR FOR NEAR TAF ISSUANCE. APPEARS RAIN SHOULD END
THROUGH ABOUT 21Z WITH VFR CONDITIONS BY 00Z.29.
/OUTLOOK FOR KMSP/
.SUN...VFR. WINDS SW 5-10 KTS.
.MON...VFR. WINDS S 10-20 KTS.
.TUE...VFR. WINDS SW-W 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...JLT
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
329 AM CDT SAT SEP 28 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
FCST GOING AS EXPECTED. SFC LOW AT 08Z VERY NEAR MARSHALL MN AND
THIS IS PROGGED BY LATEST HRRR MODEL TO LIFT TO NEAR BEMIDJ-PARK
RAPIDS AREA IN THE 12-14Z PERIOD THEN TOWARD INTERNATIONAL FALLS
BY 16Z. MAIN PRECIP DEF ZONE BAND OVER ERN SD INTO ERN ND MAINLY
HOLDING ALONG AND WEST OF A ROSEAU TO DETROIT LAKES TO WHEATON
LINE. EXPECT RAIN AREA TO SHIFT BACK EAST AS SFC LOW MOVES TOWARD
BEMIDJI BY 12-14Z.
GOING OFF LATEST HRRR/RAP AND NAM12 TWEEKED POPS TO SHOW MAIN
PRECIP ENDING IN THE SRN RRV 15-17Z...THEN 17-19Z IN THEN NRN
VALLEY AND THEN 22-23Z IN LAKE OF THE WOODS REGION. RAIN TOTALS
PER AWOS/ASOS AND OTHER STATIONS INDICATE A TENTH OR TWO AN
HOUR...WITH MOST AREAS LIKELY TO RECEIVE AROUND AN INCH TOTAL FROM
THIS SYSTEM IN THE MAIN RAIN BAND IN THE RED RIVER VALLEY.
SKIES EXPECTED TO RAPIDLY CLEAR FROM THE WEST AND SOUTHWEST THIS
AFTN WITH A GENERALLY CLEAR SKY TONIGHT. WINDS WILL GO LIGHT AND
WITH A CLEAR SKY DO EXPECT LOWS TO REACH THE UPR 30S TO LOWER
40S...WITH AN ISOLD 35-36 PSBL IN PLACES SUCH AS LANGDON OR IN THE
SHEYENNE RIVER VALLEY (I.E. COOPERSTOWN AREA).
WINDS TO TURN SOUTH SUNDAY ALONG WITH PLENTY OF SUN AND TEMPS WILL
RISE INTO THE LOWER TO MID 70S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
SOUTH WIND STAYS UP A BIT SUN NIGHT KEEPING TEMPS MILDER THAN
TONIGHT. WINDS TURN A BIT MORE SOUTHWEST ON MONDAY AND WITH 850
MB TEMPS IN THE MID TEENS EXPECT HIGHS 75 TO 80 IN MOST AREAS. DID
INTRODUCE A LOW POP MON EVE IN NE ND AND MON OVERNIGHT IN FAR NW
MN WITH SFC TROUGH PASSAGE. MAIN LOW WELL TO OUR NORTH SO ANY
PRECIP VERY LIGHT.
TUESDAY WILL BE DRY...BUT COOLER AND BREEZY IN THE WAKE OF MONDAY
NIGHT/S COLD FRONTAL PASSAGE. AFTERNOON HIGHS WILL BE 10 DEGREES
LOWER THAN MONDAY WITH WESTERLY WIND FROM 15 TO 25 MPH. NEAR ZONAL
FLOW ALOFT WEDNESDAY SHOULD RESULT IN MOSTLY DRY CONDITIONS WITH
TEMPERATURES NEAR OR SLIGHTLY COOLER THAN TUESDAY. 00 UTC GFS/ECMWF
BEGIN TO DIVERGE WEDNESDAY NIGHT THROUGH FRIDAY WITH THE TIMING AND
TRACK OF THE NEXT PACIFIC WAVE. THE GFS IS QUICKER AND FARTHER SOUTH
WHEREAS THE ECMWF IS SLOWER AND FARTHER NORTH WITH MUCH HIGHER
PRECIPITATION CHANCES ACROSS THE FORECAST AREA. MODEL RUN-TO-RUN
CONTINUITY HAS BEEN POOR...SO CONFIDENCE IS LOW AND WILL FOLLOW ALL
BLEND CHANCE POPS. DEPENDING ON THE SPEED OF THE SYSTEM...FRIDAY
COULD BE DRY OR SEE LINGERING SHOWERS DISSIPATING FROM WEST TO EAST
THROUGH THE DAY. NO MATTER THE MODEL SOLUTION...EXPECT DRY
CONDITIONS BY FRIDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE
NORTHERN PLAINS. WITH CLOUD COVER AND POTENTIAL RAIN...THURSDAY WILL
BE COOLER WITH HIGHS FROM THE MID 50S TO LOW 60S. FRIDAY WILL BE
EVEN COLDER IN THE WAKE OF THE PACIFIC WAVE/S COLD FRONT DROPPING
AFTERNOON HIGHS INTO THE 50S REGION-WIDE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI SEP 27 2013
CIGS CONTINUE IN MVFR/VFR RANGE WITH PRIMARILY VFR VSBY. AS RAIN
SHIELD LIFTS NORTHWARD COULD SEE SOME MVFR VSBY AND LOWERING CIGS
WITH MORE IFR. CONDITIONS NOT LIKELY TO CHANGE MUCH OVERNIGHT AS
RAIN OVERSPREADS REGION. DVL TAF SITE SEEING BEST CHANCE OF
STAYING VFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1149 PM CDT FRI SEP 27 2013
.UPDATE...
ISSUED AT 1139 PM CDT FRI SEP 27 2013
LEADING EDGE OF MAIN PCPN BAND FROM NEAR BJI TO VALLEY CITY AND
WILL CONTINUE TO LIFT NORTHWARD OVERNIGHT. PLENTY OF RA UPSTREAM
AND AS SURFACE LOW RIDES UP BOUNDARY CAT POPS SEEM IN ORDER AFT
MIDNIGHT. ONLY MADE SOME MINOR CHANGES TO POPS FOR THE LATE
EVENING UPDATE. NARROW RIBBON OF T ACROSS WEST CENTRAL MN
WEAKENING AND LGT STRIKES DIMINISHING.
UPDATE ISSUED AT 933 PM CDT FRI SEP 27 2013
CONTINUE TO MAKE MINOR POP ADJUSTMENTS THROUGH REMAINDER OF THE
EVENING. STEADIER RAIN BAND NOW INTO FAR NW FA SO INCREASED POPS
THERE. ELSEWHERE SOLID RAIN BAND WITH ISOLD T STILL A FEW HOURS
FROM REACHING FAR SOUTHERN FA SO CURRENT POPS OK FOR NOW. NO OTHER
CHANGES MADE.
UPDATE ISSUED AT 637 PM CDT FRI SEP 27 2013
PRIMARY FOCUS THIS UPDATE WAS TO ADJUST POPS THROUGH THE EARLY TO
MID EVENING. MORE ORGANIZED -RA APPROACHING NW FA AND INCREASED
POPS THROUGH THE EVENING THIS AREA. ELSEWHERE PCPN MORE SPOTTY
WITH MAIN RAIN BAND MOVING INTO SOUTHERN FA LATER THIS EVENING.
MADE POP ADJUSTMENTS ACCORDINGLY THESE AREAS. T THREAT AT THIS POINT
LOOKS MINIMAL. NO OTHER CHANGES NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 314 PM CDT FRI SEP 27 2013
THE CHALLENGE WILL BE RAIN CHANCES AND AMOUNTS. EVERYTHING YOU
HAVE READ IN THE PAST COUPLE DAYS (SEE PREVIOUS FORECAST
DISCUSSIONS) IS STILL VALID AND THE FORECAST IS UNFOLDING
ACCORDING TO PLAN. THE 12Z NAM IS A BIT FURTHER WEST WITH THE MAIN
BAND OF RAIN TONIGHT...AND THE RAP IS ALSO WEST. WILL CONTINUE TO
FOLLOW THE MOST CONSISTENT ECMWF (WHICH MOSTLY IS IN AGREEMENT
WITH THE GFS AND GEM). THERE WILL BE AREAS OF SHOWERS INTO THIS
EVENING BEFORE THE MORE WIDESPREAD AND MODERATE RAINFALL MOVES
INTO THE REGION (MOSTLY AFTER MIDNIGHT). STILL LOOKING LIKE AROUND
AN INCH OF WIDESPREAD RAINFALL...WITH ISOLATED HIGHER AMOUNTS
POSSIBLE. AS THE UPPER WAVE PROPAGATES NORTHEAST ON
SATURDAY...RAINFALL WILL END FROM WEST TO EAST ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 314 PM CDT FRI SEP 27 2013
SUNDAY-MONDAY...FAST ZONAL UPPER FLOW ALONG WITH LOW LEVEL
SOUTHERLY FLOW WILL DEVELOP. THIS SHOULD LEAD TO DRY WEATHER
ALONG WITH TEMPERATURES ABOVE NORMAL. 12Z MODELS DO NOT SHOW ANY
STRONGER UPPER WAVES DURING THIS PERIOD.
MONDAY NIGHT-FRIDAY...ZONAL FLOW TO START THE EXTENDED FORECAST
PERIOD ON TUESDAY...ECMWF HINTS AT A SHORT WAVE PASSING THROUGH
THE FLOW PAINTING SOME PCPN. BUT THIS SEEMS NEW AND IS CONTRARY TO
OTHER GUIDANCE SO WILL KEEP TUESDAY DRY. 850 MB TEMPS IN THE 10 TO
15C RANGE POINT TO A WARM START TO THE WEEK WITH SOUTHERN SPOTS
MAXING OUT IN THE 70S.
ECMWF ALSO APPEARS TO BE PLACING PCPN A LITTLE TOO FAR NORTH
FOR WEDNESDAY WITH HIGH PRESSURE OVER THE REGION AND HAVE OPTED TO
CONTINUE OUR DRY FCST THROUGH MIDWEEK. SURFACE TROUGH/FRONT SHOULD
MAKE ITS WAY TO THE CWA BY THURSDAY HOWEVER...WITH INDICATIONS OF
CAPE SUITABLE FOR SOME THUNDER...TRANSITIONING TO RAIN SHOWERS BY
FRIDAY AS THE SYSTEM MOVES WELL EAST. THE MILD TEMPS OF THE FIRST
HALF OF THE WEEK WILL BE GONE BY FRIDAY...AS COLDER IS DRAWN DOWN
FROM CANADA LEE OF THE TROUGH...LEAVING THE MERCURY IN THE 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI SEP 27 2013
CIGS CONTINUE IN MVFR/VFR RANGE WITH PRIMARILY VFR VSBY. AS RAIN
SHIELD LIFTS NORTHWARD COULD SEE SOME MVFR VSBY AND LOWERING CIGS
WITH MORE IFR. CONDITIONS NOT LIKELY TO CHANGE MUCH OVERNIGHT AS
RAIN OVERSPREADS REGION. DVL TAF SITE SEEING BEST CHANCE OF
STAYING VFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
337 AM CDT SAT SEP 28 2013
.SHORT TERM...
Today and Tonight
I`m expecting showers and thunderstorms to bring rain to West
central Texas during the next 24 hours. Everything has come
together; we have low-level moisture, instability, and lift. If most
of West Central Texas doesn`t receive good rainfall today and
tonight, we`re going to miss a really great opportunity.
Precipitable water values from the GFS increase to around 2 inches
by this afternoon. So, some thunderstorms may produce locally heavy
rainfall. The main thunderstorm threats will be heavy rainfall and
deadly lightning. Some areas may receive one half to one inch of
rain today, while a few locations may have up to two inches today.
I`m expecting convection to be along and ahead of the cold front.
I`m expect the front to move into our northwest Big Country counties
by mid morning; this timing fits well with the latest RUC and the
06Z NAM. I`m thinking the best rain chances today will be across the
central and eastern Big Country and most of the Heartland; that`s
where the deeper moisture will be. As the front shifts slowly
southeast, I expect the better rain chances to shift to mainly our
Northwest Hill Country counties overnight tonight. As for
temperatures, numbers close to guidance look good.
Huber
.LONG TERM...
Sunday through Saturday...
A steady warm up can be expected next week, with a possible strong
cold front by next weekend. The cold front that will move through
West Central Texas today, will be south of the area Sunday morning.
The majority of the convection will be south of the area, but
lingering showers and thunderstorms will be possible across mainly
the southern and eastern counties. I have included slight chance to
chance PoPs, with most of the convection ending by 18z. Highs on
Sunday will generally be in the upper 70s to lower 80s, while
overnight lows drop into the lower to mid 60s.
A steady warm up is forecast through much of the week. Above normal
temperatures are forecast with highs in the upper 80s to lower 90s,
while overnight lows drop into the 60s. Our next weather player will
be a potent upper level trough that is forecast to be near the Four
Corners region by late Thursday, then swing across the Southern
Plains Saturday. This will drive a fairly strong cold front through
the area on Saturday. For now, I have trended temperatures down and
introduced slight chance PoPs across parts of the area. These may
need to be increased in the near future if the current model trends
continue. Below normal temperatures can be expected for the
remainder of next weekend and into the early part of following week.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 81 59 80 62 87 / 90 60 20 5 5
San Angelo 83 61 81 62 89 / 80 60 20 10 5
Junction 85 66 80 63 86 / 80 80 50 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Huber/Daniels
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
312 AM CDT SAT SEP 28 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CDT SAT SEP 28 2013
MAIN FOCUS THROUGH THE SHORT TERM WILL BE COLD FRONTAL PASSAGE AND
ASSOCIATED RAINFALL.
SURFACE MAP EARLY THIS MORNING HAS A COLD FRONT EXTENDING FROM
WESTERN ONTARIO CANADA/WESTERN MN...THROUGH EASTERN NEBRASKA AND
CENTRAL KS. RADAR MOSAIC SHOWING A RESPECTABLE 100 MILE WIDE BAND OF
FAIRLY SOLID SHOWERS AND AN OCCASIONAL EMBEDDED THUNDERSTORM BEHIND
THE FRONT IN STRONG 850-700MB FRONTOGENESIS/MODERATE MOISTURE
TRANSPORT. THIS ENERGY WAS BEING STEERED BY A VIGOROUS/DEEP
MID-LEVEL TROUGH MOVING EAST ACROSS EASTERN MT/WY/CO PER WATER VAPOR
SATELLITE/RAP 500MB ANALYSIS. ALSO NOTED ON WATER VAPOR IMAGERY WAS
A NARROW CORRIDOR OF SUBTROPICAL TAP STREAMING NORTHWARD AHEAD OF
THIS WAVE. RAP PRECIPITABLE WATER VALUES WHERE THE SHOWERS/EMBEDDED
THUNDERSTORMS WERE FALLING ARE IN THE 1.5-2" RANGE OR 200-250
PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. OTHERWISE...SKIES ACROSS
THE FORECAST AREA RANGED FROM CLEAR TO PARTLY CLOUDY WITH MILD
TEMPERATURES IN THE MIDDLE AND UPPER 50S...TO THE MIDDLE 60S.
LOOK FOR THE COLD FRONT TO MAKE EASTWARD PROGRESSION ACROSS THE AREA
TODAY. ALTHOUGH MOISTURE TRANSPORT DIMINISHES SOME THROUGH THE
DAY...700-300 PV-ADVECTION/850-700MB FRONTOGENESIS REMAINS FAIRLY
STRONG. BASED ON THIS SIGNAL AND WRF MODEL OUTPUT...APPEARS THE AREA
WILL SEE SOME RAINFALL. RAINFALL AMOUNTS ARE EXPECTED TO BE IN THE
1/4 TO 1/2 INCH RANGE. SOME ELEVATED INSTABILITY WILL ALSO EXIST
GENERALLY ABOVE 700MB FOR POCKETS OF THUNDER WITHIN THIS BAND OF
SHOWERS. LOOK FOR TEMPERATURES TO TOP OFF IN THE UPPER 60S TO THE
MIDDLE 70S...THEN SLOWLY FALL THROUGH THIS AFTERNOON WITH THE
FRONTAL PASSAGE AND IN THE SHOWER ACTIVITY.
PLAN ON THE FRONT AND RAIN TO PUSH EAST OF THE AREA THIS EVENING
WITH HIGH PRESSURE BUILDING OVERHEAD OVERNIGHT. CLEARING SKIES AND
RELATIVELY MOIST LOWER BOUNDARY LAYER ARE EXPECTED TO PRODUCE PATCHY
FOG LATE TONIGHT...MAINLY IN THE RIVER VALLEYS WHERE WINDS WILL BE
MORE LIKELY TO DECOUPLE. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE
40S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CDT SAT SEP 28 2013
GFS AND ECMWF ARE IN EXCELLENT AGREEMENT IN KEEPING THE MAIN STORM
TRACK NORTH OVER CENTRAL CANADA FOR SUNDAY THROUGH WEDNESDAY. THIS
KEEPS US DRY WITH BREEZY SOUTH-SOUTHWEST SURFACE FLOW //AT LEAST
INTO TUESDAY//WHICH WILL HELP DRAW UNSEASONABLY WARM AIR INTO THE
REGION. LOOK FOR HIGHS SUNDAY IN THE UPPER 60S TO THE MIDDLE
70S...WARMING INTO THE 70S TO AROUND THE 80 DEGREE MARK TUESDAY AND
WEDNESDAY.
LOW PRESSURE THEN MOVES OUT OF THE INTERMOUNTAIN WEST AND INTO THE
PLAINS WEDNESDAY NIGHT AND THURSDAY WITH INCREASING MOISTURE
TRANSPORT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. RESULT
WILL BE INCREASING CLOUDS WITH A GOOD CHANCE FOR SHOWERS AND
THUNDERSTORMS.
MODELS THEN DIVERGE A BIT FOR THURSDAY NIGHT INTO FRIDAY WITH
HANDLING OF THE MAIN SURFACE LOW MOVING OUT OF THE PLAINS. THE ECMWF
TAKES THE LOW TO NEAR THE ARROWHEAD OF MN BY FRIDAY EVENING WHICH
WOULD KEEP US WARMER WITH ISOLATED SHOWERS AND THUNDERSTORMS OR
POSSIBLY COMPLETELY DRY WITH A CAP IN PLACE. THE GFS ON THE OTHER
HAND FAVORS A FARTHER SOUTH SOLUTION WITH THE LOW WHICH WOULD KEEP
US IN MORE OF A DEFORMATION RAIN SHIELD AND COOLER. FOR NOW...WILL
FOLLOW A MODEL CONSENSUS WITH RESULTING HIGH TEMPERATURES IN THE 60S
AND SMALLER-END RAIN PROBABILITIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT
1100 PM CDT FRI SEP 27 2013
LLWS A CONCERN THROUGH THE OVERNIGHT HOURS WITH 35 TO 45 KTS OF WIND
IN THE 1-2 KFT LAYER FOR BOTH KRST/KLSE...PER BUFKIT SOUNDINGS.
MIXING WILL IMPROVE THESE CONDITIONS EARLY ON SAT. WILL CONTINUE
MENTION IN TAFS.
COLD FRONT WILL SWEEP WEST-EAST ACROSS THE REGION ON SAT...LIKELY
PASSING KRST BETWEEN 20-22Z AND KLSE 21-23Z. THE BULK OF THE FORCING
WITH THE SYSTEM WILL BE ALONG AND POST THE FRONT...WITH NO
INSTABILTY TO TAP INTO. STILL...ENOUGH MECHANICAL LIFTING VIA THE
FRONT THAT A FEW THUNDERSTORMS ARE POSSIBLE. EXPECT A LOWERING OF
CIGS WITH THE ADVENT OF THE FRONT...AND A PERIOD OF MVFR/IFR POST
THE BOUNDARY. ANY TS THREAT WOULD BE SHORT LIVED AND AROUND THE
FRONT. QUICK MOVEMENT OF THE FRONT WILL RESULT IN CLEARING FRIDAY
EVENING...WITH SKC CONDITIONS OVERNIGHT.
ALONG WITH THE LLWS TO CONTEND WITH TONIGHT...SFC PRESSURE GRADIENT
STAYS TIGHT...AND THE WINDS WILL BE FAIRLY BREEZY THROUGH SAT
AFTERNOON. EXPECT GUSTY CONDITIONS AHEAD OF THE FRONT.
CLEARING SKIES AFTER THE EXPECTED RAINS BRINGS THOUGHTS OF FOG
POTENTIAL FOR LATE SATURDAY NIGHT. CURRENTLY...THE SFC HIGH CENTER
IS PROGGED TO BE WELL SOUTHWEST OF THE LOCAL AREA...WHILE NEAR SFC
WINDS STAY BREEZY. DRIER AIR WILL ALSO BE ADVECTED IN POST THE
FRONT. THINK THE FOG THREAT IS MINIMAL AT KRST...BUT RIVER VALLEY
FOG AND POSSIBLE IMPACTS AT KLSE WILL CONTINUE TO BE EVALUATED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
949 AM CDT Sat Sep 28 2013
.UPDATE...
Issued at 949 AM CDT SAT SEP 28 2013
No major changes to forecast thinking as rain and storms move through
this morning. Any thunder is confined to the leading edge of this
activity which has already made it into the Sedalia and Kirksville
areas. These storms may become a bit stronger as they track toward
eastern MO later today where temps are rising into the mid/upper 70s,
but threat for any strong storms west of the US-63 corridor is very
low. Rainfall amounts so far have generally been around a quarter of
an inch or less, though some gauges on the west side of the KC metro
have picked up over a half inch so far. Followed closely the HRRR for
the back edge of this activity since this model has had a good handle
on this system so far. Looks like rapid clearing will make it to the
I-35 corridor by early afternoon and into far eastern portions of the
forecast area by late afternoon/early evening.
&&
.SHORT TERM...(Today through Monday Night)
Issued at 344 AM CDT SAT SEP 28 2013
Forecast is still on line for much of the area to get some rain on
Saturday. Radar trends across central Kansas and eastern Nebraska
show widespread showers and thunderstorms. They appear to be in
association with a rather potent neutrally tilted trough, which is
currently situated over the western Plains. While this mid level
trough is providing decent mid level forcing for ascent the surface
cold front also seems to be a contributing factor of where the more
widespread showery activity is located. Currently the surface cold
front is located on a line from KSUX through KAUH and KGBD. The first
echoes should be encroaching upon the forecast area in far NW
Missouri within the hour and precip will continue to spread eastward
through the rest of the morning and afternoon hours. Expect showers
to form in the KC Metro area perhaps around 12z, lasting through
around 18z before dissipating and moving off to the east. Areas of
central Missouri will likely see precipitation begin in the late
morning or early afternoon, lasting through the afternoon hours
before moving off to the east by later this evening. Currently not
expecting much in the way of a severe threat, however models do
indicate perhaps up to 500-1000 J/kg of MU Cape as the showers move
through, which may increase the coverage of thunderstorm activity. In
conjunction with the moderate instability NAM does hint at around
20-30 kts of 0-6 km wind shear, which may add to the updraft strength
of select storms. As a result, still expect a NIL severe weather day,
however coverage of thunderstorm activity may increase slightly, and
perhaps an isolated updraft or two could bring some small hail and/or
gusty winds. As mentioned above, expect showers and thunderstorms to
exit the area from west to east by this evening. Expected QPF for
this system will be on the low end, considering it`s convective
nature, but with it`s progressive nature expect only a quarter to
half inch of rain, with perhaps a few isolated locations receiving
higher amounts of around three quarters of an inch.
Northerly cool and dry air will then settle into the area for the
remainder of the weekend, as the surface high moves into Missouri.
At the moment expecting overnight lows on Saturday night into Sunday
morning to drop well into the 40s, especially along the northern
half of the forecast area, with perhaps some lower 50s further
south. Sunday will bring sunny conditions, with perhaps slightly
warmer temperatures in the middle 70s. Monday will be a near repeat
of Sunday with sunny skies and temperatures in the middle to upper
70s.
.LONG TERM...(Tuesday through Friday)
Issued at 344 AM CDT SAT SEP 28 2013
Above normal temperatures and dry conditions are expected for
Tuesday and most of Wednesday, as broad zonal flow gradually turns
west southwest and southerly low-level winds increase. A deep trough
building over the northeast Pacific will begin dropping southeast by
late Wednesday, orienting the flow more southwest-northeast and
allowing a few disturbances to lift northeast into the forecast area
from early Thursday morning through Friday. This shift in the
pattern will make showers and storms possible for much of the latter
half of the week, but will also hold temperatures down a bit with
cloud cover and precipitation around the area. Model agreement is
still poor for timing the main trough axis into the central CONUS,
but precipitation will be likely with that system as it pushes
through, sometime Friday or Saturday. Significantly more seasonable
temperatures are expected behind this system, especially if the low
cuts off as indicated by the 00z runs of the EC and GFS.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 625 AM CDT SAT SEP 28 2013
First wave of showers and thunderstorms is currently moving through
the terminals. The showers are separated so there will not be any
extended period of diminished conditions, however there may be a
brief shower at the terminals over the next couple hours. The more
widespread precipitation gets to the terminals around 13z, with a
more extended period of deteriorated conditions. Expect the bulk of
the precipitation to move through by 15z to 16z, with the lingering
showery activity clearing the area by 18z. Thereafter expect mostly
VFR conditions with light northerly winds for remainder of the
period.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Leighton
LONG TERM...Laflin
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT SAT SEP 28 2013
.UPDATE...
ISSUED AT 955 AM CDT SAT SEP 28 2013
1450Z RADAR IMAGERY SHOWS WIDESPREAD RAINFALL CONTINUES ACROSS THE
REGION. THERE APPEARS TO BE A BRIEF BREAK IN ACTIVITY WITHIN THE
CENTRAL VALLEY...BUT WILL NOT GET TOO CUTE WITH THE FORECAST. THE
AREA OF RAINFALL EAST OF THE VALLEY LIKELY ASSOCIATED WITH MID-
LEVEL FRONTOGENESIS...WHICH WILL ADVECT NORTHEASTWARD AND OUT OF
THE REGION QUICKLY. THE AREA OF RAINFALL WEST OF THE VALLEY LIKELY
ASSOCIATED WITH THE MAIN UPPER WAVE...AS SEEN IN 500MB-300MB
Q-VECTOR CONVERGENCE FROM THE MODELS. WILL FOLLOW THIS FORCING
FROM THE 12Z NAM FOR ENDING OF THE CATEGORICAL POPS TODAY. THIS
DELAYS THE ENDING OF RAINFALL AN HOUR TO TWO FROM PREVIOUS
FORECAST. THE 12Z HRRR/RAP AGREE WITH THIS CHANGE. WITH
THAT...ALSO DELAYED CLEARING A FEW HOURS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
FCST GOING AS EXPECTED. SFC LOW AT 08Z VERY NEAR MARSHALL MN AND
THIS IS PROGGED BY LATEST HRRR MODEL TO LIFT TO NEAR BEMIDJI-PARK
RAPIDS AREA IN THE 12-14Z PERIOD THEN TOWARD INTERNATIONAL FALLS
BY 16Z. MAIN PRECIP DEF ZONE BAND OVER ERN SD INTO ERN ND MAINLY
HOLDING ALONG AND WEST OF A ROSEAU TO DETROIT LAKES TO WHEATON
LINE. EXPECT RAIN AREA TO SHIFT BACK EAST AS SFC LOW MOVES TOWARD
BEMIDJI BY 12-14Z.
GOING OFF LATEST HRRR/RAP AND NAM12 TWEAKED POPS TO SHOW MAIN
PRECIP ENDING IN THE SRN RRV 15-17Z...THEN 17-19Z IN THEN NRN
VALLEY AND THEN 22-23Z IN LAKE OF THE WOODS REGION. RAIN TOTALS
PER AWOS/ASOS AND OTHER STATIONS INDICATE A TENTH OR TWO AN
HOUR...WITH MOST AREAS LIKELY TO RECEIVE AROUND AN INCH TOTAL FROM
THIS SYSTEM IN THE MAIN RAIN BAND IN THE RED RIVER VALLEY.
SKIES EXPECTED TO RAPIDLY CLEAR FROM THE WEST AND SOUTHWEST THIS
AFTN WITH A GENERALLY CLEAR SKY TONIGHT. WINDS WILL GO LIGHT AND
WITH A CLEAR SKY DO EXPECT LOWS TO REACH THE UPR 30S TO LOWER
40S...WITH AN ISOLD 35-36 PSBL IN PLACES SUCH AS LANGDON OR IN THE
SHEYENNE RIVER VALLEY (I.E. COOPERSTOWN AREA).
WINDS TO TURN SOUTH SUNDAY ALONG WITH PLENTY OF SUN AND TEMPS WILL
RISE INTO THE LOWER TO MID 70S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
SOUTH WIND STAYS UP A BIT SUN NIGHT KEEPING TEMPS MILDER THAN
TONIGHT. WINDS TURN A BIT MORE SOUTHWEST ON MONDAY AND WITH 850
MB TEMPS IN THE MID TEENS EXPECT HIGHS 75 TO 80 IN MOST AREAS. DID
INTRODUCE A LOW POP MON EVE IN NE ND AND MON OVERNIGHT IN FAR NW
MN WITH SFC TROUGH PASSAGE. MAIN LOW WELL TO OUR NORTH SO ANY
PRECIP VERY LIGHT.
TUESDAY WILL BE DRY...BUT COOLER AND BREEZY IN THE WAKE OF MONDAY
NIGHT/S COLD FRONTAL PASSAGE. AFTERNOON HIGHS WILL BE 10 DEGREES
LOWER THAN MONDAY WITH WESTERLY WIND FROM 15 TO 25 MPH. NEAR ZONAL
FLOW ALOFT WEDNESDAY SHOULD RESULT IN MOSTLY DRY CONDITIONS WITH
TEMPERATURES NEAR OR SLIGHTLY COOLER THAN TUESDAY. 00 UTC GFS/ECMWF
BEGIN TO DIVERGE WEDNESDAY NIGHT THROUGH FRIDAY WITH THE TIMING AND
TRACK OF THE NEXT PACIFIC WAVE. THE GFS IS QUICKER AND FARTHER SOUTH
WHEREAS THE ECMWF IS SLOWER AND FARTHER NORTH WITH MUCH HIGHER
PRECIPITATION CHANCES ACROSS THE FORECAST AREA. MODEL RUN-TO-RUN
CONTINUITY HAS BEEN POOR...SO CONFIDENCE IS LOW AND WILL FOLLOW ALL
BLEND CHANCE POPS. DEPENDING ON THE SPEED OF THE SYSTEM...FRIDAY
COULD BE DRY OR SEE LINGERING SHOWERS DISSIPATING FROM WEST TO EAST
THROUGH THE DAY. NO MATTER THE MODEL SOLUTION...EXPECT DRY
CONDITIONS BY FRIDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE
NORTHERN PLAINS. WITH CLOUD COVER AND POTENTIAL RAIN...THURSDAY WILL
BE COOLER WITH HIGHS FROM THE MID 50S TO LOW 60S. FRIDAY WILL BE
EVEN COLDER IN THE WAKE OF THE PACIFIC WAVE/S COLD FRONT DROPPING
AFTERNOON HIGHS INTO THE 50S REGION-WIDE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 955 AM CDT SAT SEP 28 2013
RAIN ENDING IN THE DEVILS LAKE BASIN WITH MVFR CIG IMPRVG TO VFR
16Z-17Z. THIS MORNINGS RAIN TO SLOWLY MOVE EAST OF THE AREA WITH
MOSTLY MVFR CIGS AND VSBYS...THOUGH LCL IFR CIGS BECOMING DOMINATE
THROUGH 18Z VALLEY AND 21Z FAR EAST. CLEARING LINE MAY BE QUITE
SHARP AND EXACT TIMING LIKELY WILL NEED UPDATING THROUGH THE DAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...RIDDLE/EWENS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
734 AM CDT SAT SEP 28 2013
.UPDATE...
ISSUED AT 731 AM CDT SAT SEP 28 2013
WESTERN EDGE OF RAIN BAND REMAINS ROLLA TO JUST EAST OF BISMARCK
AND LOOKS TO BE A BIT SLOWER THAN EARLIER THINKING IN SPREADING
EAST. THUS INCREASED POPS A BIT AND DELAYED ENDING OF RAIN JUST A
TAD THRU EARLY AFTN INTO THE VALLEY AND NW MN.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
FCST GOING AS EXPECTED. SFC LOW AT 08Z VERY NEAR MARSHALL MN AND
THIS IS PROGGED BY LATEST HRRR MODEL TO LIFT TO NEAR BEMIDJ-PARK
RAPIDS AREA IN THE 12-14Z PERIOD THEN TOWARD INTERNATIONAL FALLS
BY 16Z. MAIN PRECIP DEF ZONE BAND OVER ERN SD INTO ERN ND MAINLY
HOLDING ALONG AND WEST OF A ROSEAU TO DETROIT LAKES TO WHEATON
LINE. EXPECT RAIN AREA TO SHIFT BACK EAST AS SFC LOW MOVES TOWARD
BEMIDJI BY 12-14Z.
GOING OFF LATEST HRRR/RAP AND NAM12 TWEEKED POPS TO SHOW MAIN
PRECIP ENDING IN THE SRN RRV 15-17Z...THEN 17-19Z IN THEN NRN
VALLEY AND THEN 22-23Z IN LAKE OF THE WOODS REGION. RAIN TOTALS
PER AWOS/ASOS AND OTHER STATIONS INDICATE A TENTH OR TWO AN
HOUR...WITH MOST AREAS LIKELY TO RECEIVE AROUND AN INCH TOTAL FROM
THIS SYSTEM IN THE MAIN RAIN BAND IN THE RED RIVER VALLEY.
SKIES EXPECTED TO RAPIDLY CLEAR FROM THE WEST AND SOUTHWEST THIS
AFTN WITH A GENERALLY CLEAR SKY TONIGHT. WINDS WILL GO LIGHT AND
WITH A CLEAR SKY DO EXPECT LOWS TO REACH THE UPR 30S TO LOWER
40S...WITH AN ISOLD 35-36 PSBL IN PLACES SUCH AS LANGDON OR IN THE
SHEYENNE RIVER VALLEY (I.E. COOPERSTOWN AREA).
WINDS TO TURN SOUTH SUNDAY ALONG WITH PLENTY OF SUN AND TEMPS WILL
RISE INTO THE LOWER TO MID 70S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
SOUTH WIND STAYS UP A BIT SUN NIGHT KEEPING TEMPS MILDER THAN
TONIGHT. WINDS TURN A BIT MORE SOUTHWEST ON MONDAY AND WITH 850
MB TEMPS IN THE MID TEENS EXPECT HIGHS 75 TO 80 IN MOST AREAS. DID
INTRODUCE A LOW POP MON EVE IN NE ND AND MON OVERNIGHT IN FAR NW
MN WITH SFC TROUGH PASSAGE. MAIN LOW WELL TO OUR NORTH SO ANY
PRECIP VERY LIGHT.
TUESDAY WILL BE DRY...BUT COOLER AND BREEZY IN THE WAKE OF MONDAY
NIGHT/S COLD FRONTAL PASSAGE. AFTERNOON HIGHS WILL BE 10 DEGREES
LOWER THAN MONDAY WITH WESTERLY WIND FROM 15 TO 25 MPH. NEAR ZONAL
FLOW ALOFT WEDNESDAY SHOULD RESULT IN MOSTLY DRY CONDITIONS WITH
TEMPERATURES NEAR OR SLIGHTLY COOLER THAN TUESDAY. 00 UTC GFS/ECMWF
BEGIN TO DIVERGE WEDNESDAY NIGHT THROUGH FRIDAY WITH THE TIMING AND
TRACK OF THE NEXT PACIFIC WAVE. THE GFS IS QUICKER AND FARTHER SOUTH
WHEREAS THE ECMWF IS SLOWER AND FARTHER NORTH WITH MUCH HIGHER
PRECIPITATION CHANCES ACROSS THE FORECAST AREA. MODEL RUN-TO-RUN
CONTINUITY HAS BEEN POOR...SO CONFIDENCE IS LOW AND WILL FOLLOW ALL
BLEND CHANCE POPS. DEPENDING ON THE SPEED OF THE SYSTEM...FRIDAY
COULD BE DRY OR SEE LINGERING SHOWERS DISSIPATING FROM WEST TO EAST
THROUGH THE DAY. NO MATTER THE MODEL SOLUTION...EXPECT DRY
CONDITIONS BY FRIDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE
NORTHERN PLAINS. WITH CLOUD COVER AND POTENTIAL RAIN...THURSDAY WILL
BE COOLER WITH HIGHS FROM THE MID 50S TO LOW 60S. FRIDAY WILL BE
EVEN COLDER IN THE WAKE OF THE PACIFIC WAVE/S COLD FRONT DROPPING
AFTERNOON HIGHS INTO THE 50S REGION-WIDE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 731 AM CDT SAT SEP 28 2013
THIS MORNING RAIN TO DOMINATE THE AREA WITH MOSTLY MVFR CIGS AND
VSBYS...THOUGH LCL IFR CIGS BECOMING DOMINATE 12Z-15Z PERIOD IN
THE VALLEY INTO NRN MN. EXPECT IMPROVEMENT THIS AFTN IN ERN ND AND
EARLY THIS EVE IN NRN MN. CLEARING LINE MAY BE QUITE SHARP AND
EXACT TIMING LIKELY WILL NEED UPDATING THROUGH THE DAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
645 AM CDT SAT SEP 28 2013
.DISCUSSION...
Please see aviation below for discussion.
&&
.AVIATION...
Look for very challenging flight weather conditions across West
Central Texas during the next 24 hours. Ceilings in the MVFR range
and Thunderstorms will be the primary concerns today. Overnight
tonight, the primary concern will be ceilings. I believe MVFR
ceilings will end across the Big Country and Concho Valley by 06Z.
However, I expect MVFR ceilings to linger elsewhere overnight.
Huber
&&
.PREV DISCUSSION... /ISSUED 337 AM CDT SAT SEP 28 2013/
SHORT TERM...
Today and Tonight
I`m expecting showers and thunderstorms to bring rain to West
central Texas during the next 24 hours. Everything has come
together; we have low-level moisture, instability, and lift. If most
of West Central Texas doesn`t receive good rainfall today and
tonight, we`re going to miss a really great opportunity.
Precipitable water values from the GFS increase to around 2 inches
by this afternoon. So, some thunderstorms may produce locally heavy
rainfall. The main thunderstorm threats will be heavy rainfall and
deadly lightning. Some areas may receive one half to one inch of
rain today, while a few locations may have up to two inches today.
I`m expecting convection to be along and ahead of the cold front.
I`m expect the front to move into our northwest Big Country counties
by mid morning; this timing fits well with the latest RUC and the
06Z NAM. I`m thinking the best rain chances today will be across the
central and eastern Big Country and most of the Heartland; that`s
where the deeper moisture will be. As the front shifts slowly
southeast, I expect the better rain chances to shift to mainly our
Northwest Hill Country counties overnight tonight. As for
temperatures, numbers close to guidance look good.
Huber
LONG TERM...
Sunday through Saturday...
A steady warm up can be expected next week, with a possible strong
cold front by next weekend. The cold front that will move through
West Central Texas today, will be south of the area Sunday morning.
The majority of the convection will be south of the area, but
lingering showers and thunderstorms will be possible across mainly
the southern and eastern counties. I have included slight chance to
chance PoPs, with most of the convection ending by 18z. Highs on
Sunday will generally be in the upper 70s to lower 80s, while
overnight lows drop into the lower to mid 60s.
A steady warm up is forecast through much of the week. Above normal
temperatures are forecast with highs in the upper 80s to lower 90s,
while overnight lows drop into the 60s. Our next weather player will
be a potent upper level trough that is forecast to be near the Four
Corners region by late Thursday, then swing across the Southern
Plains Saturday. This will drive a fairly strong cold front through
the area on Saturday. For now, I have trended temperatures down and
introduced slight chance PoPs across parts of the area. These may
need to be increased in the near future if the current model trends
continue. Below normal temperatures can be expected for the
remainder of next weekend and into the early part of following week.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 81 59 80 62 87 / 90 60 20 5 5
San Angelo 83 61 81 62 89 / 80 60 20 10 5
Junction 85 66 80 63 86 / 80 80 50 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Huber/Daniels
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
640 AM CDT SAT SEP 28 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CDT SAT SEP 28 2013
MAIN FOCUS THROUGH THE SHORT TERM WILL BE COLD FRONTAL PASSAGE AND
ASSOCIATED RAINFALL.
SURFACE MAP EARLY THIS MORNING HAS A COLD FRONT EXTENDING FROM
WESTERN ONTARIO CANADA/WESTERN MN...THROUGH EASTERN NEBRASKA AND
CENTRAL KS. RADAR MOSAIC SHOWING A RESPECTABLE 100 MILE WIDE BAND OF
FAIRLY SOLID SHOWERS AND AN OCCASIONAL EMBEDDED THUNDERSTORM BEHIND
THE FRONT IN STRONG 850-700MB FRONTOGENESIS/MODERATE MOISTURE
TRANSPORT. THIS ENERGY WAS BEING STEERED BY A VIGOROUS/DEEP
MID-LEVEL TROUGH MOVING EAST ACROSS EASTERN MT/WY/CO PER WATER VAPOR
SATELLITE/RAP 500MB ANALYSIS. ALSO NOTED ON WATER VAPOR IMAGERY WAS
A NARROW CORRIDOR OF SUBTROPICAL TAP STREAMING NORTHWARD AHEAD OF
THIS WAVE. RAP PRECIPITABLE WATER VALUES WHERE THE SHOWERS/EMBEDDED
THUNDERSTORMS WERE FALLING ARE IN THE 1.5-2" RANGE OR 200-250
PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. OTHERWISE...SKIES ACROSS
THE FORECAST AREA RANGED FROM CLEAR TO PARTLY CLOUDY WITH MILD
TEMPERATURES IN THE MIDDLE AND UPPER 50S...TO THE MIDDLE 60S.
LOOK FOR THE COLD FRONT TO MAKE EASTWARD PROGRESSION ACROSS THE AREA
TODAY. ALTHOUGH MOISTURE TRANSPORT DIMINISHES SOME THROUGH THE
DAY...700-300 PV-ADVECTION/850-700MB FRONTOGENESIS REMAINS FAIRLY
STRONG. BASED ON THIS SIGNAL AND WRF MODEL OUTPUT...APPEARS THE AREA
WILL SEE SOME RAINFALL. RAINFALL AMOUNTS ARE EXPECTED TO BE IN THE
1/4 TO 1/2 INCH RANGE. SOME ELEVATED INSTABILITY WILL ALSO EXIST
GENERALLY ABOVE 700MB FOR POCKETS OF THUNDER WITHIN THIS BAND OF
SHOWERS. LOOK FOR TEMPERATURES TO TOP OFF IN THE UPPER 60S TO THE
MIDDLE 70S...THEN SLOWLY FALL THROUGH THIS AFTERNOON WITH THE
FRONTAL PASSAGE AND IN THE SHOWER ACTIVITY.
PLAN ON THE FRONT AND RAIN TO PUSH EAST OF THE AREA THIS EVENING
WITH HIGH PRESSURE BUILDING OVERHEAD OVERNIGHT. CLEARING SKIES AND
RELATIVELY MOIST LOWER BOUNDARY LAYER ARE EXPECTED TO PRODUCE PATCHY
FOG LATE TONIGHT...MAINLY IN THE RIVER VALLEYS WHERE WINDS WILL BE
MORE LIKELY TO DECOUPLE. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE
40S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CDT SAT SEP 28 2013
GFS AND ECMWF ARE IN EXCELLENT AGREEMENT IN KEEPING THE MAIN STORM
TRACK NORTH OVER CENTRAL CANADA FOR SUNDAY THROUGH WEDNESDAY. THIS
KEEPS US DRY WITH BREEZY SOUTH-SOUTHWEST SURFACE FLOW //AT LEAST
INTO TUESDAY//WHICH WILL HELP DRAW UNSEASONABLY WARM AIR INTO THE
REGION. LOOK FOR HIGHS SUNDAY IN THE UPPER 60S TO THE MIDDLE
70S...WARMING INTO THE 70S TO AROUND THE 80 DEGREE MARK TUESDAY AND
WEDNESDAY.
LOW PRESSURE THEN MOVES OUT OF THE INTERMOUNTAIN WEST AND INTO THE
PLAINS WEDNESDAY NIGHT AND THURSDAY WITH INCREASING MOISTURE
TRANSPORT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. RESULT
WILL BE INCREASING CLOUDS WITH A GOOD CHANCE FOR SHOWERS AND
THUNDERSTORMS.
MODELS THEN DIVERGE A BIT FOR THURSDAY NIGHT INTO FRIDAY WITH
HANDLING OF THE MAIN SURFACE LOW MOVING OUT OF THE PLAINS. THE ECMWF
TAKES THE LOW TO NEAR THE ARROWHEAD OF MN BY FRIDAY EVENING WHICH
WOULD KEEP US WARMER WITH ISOLATED SHOWERS AND THUNDERSTORMS OR
POSSIBLY COMPLETELY DRY WITH A CAP IN PLACE. THE GFS ON THE OTHER
HAND FAVORS A FARTHER SOUTH SOLUTION WITH THE LOW WHICH WOULD KEEP
US IN MORE OF A DEFORMATION RAIN SHIELD AND COOLER. FOR NOW...WILL
FOLLOW A MODEL CONSENSUS WITH RESULTING HIGH TEMPERATURES IN THE 60S
AND SMALLER-END RAIN PROBABILITIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 639 AM CDT SAT SEP 28 2013
MULTIPLE CONCERNS FOR THE FORECAST...
1. WINDS. GUSTS HAVE PERSISTED THROUGH THE OVERNIGHT HOURS AT
RST...STRONG ENOUGH TO BE ABLE TO REMOVE THE LOW LEVEL WIND SHEAR
THERE. LOW LEVEL WIND SHEAR IS NEEDED AT LSE UNTIL 14Z WHEN
DAYTIME MIXING WILL ALLOW GUSTS TO DEVELOP. GUSTS AT BOTH SITES
LOOK TO PICK UP TOWARDS 16-17Z AS DAYTIME MIXING BRINGS DOWN A
CORE OF STRONGER WINDS JUST AHEAD OF A COLD FRONT MARCHING EAST.
PRESENTLY HAVE GUSTS OF 25-30 KT...BUT THESE COULD BE HIGHER IF
TEMPERATURES WARM MORE THAN FORECAST. WINDS WILL VEER FROM SOUTH
TO WEST AS THE FRONT CROSSES BETWEEN 20-23Z. GUSTS AND SPEEDS ARE
ALSO EXPECTED TO DIMINISH WITH THE FRONTAL PASSAGE...AIDED EVEN
FURTHER IN THE EVENING WITH LOSS OF HEATING.
2. IMPACT FROM BAND OF SHOWERS ALONG/BEHIND COLD FRONT. THESE SHOWERS
LOOK TO MOVE INTO THE TAF SITES BETWEEN 15-18Z AND EXIST BY
21-23Z. CEILINGS SHOULD DROP TO MVFR WITH VISIBILITIES POSSIBLY
TO MVFR AT TIMES AS WELL. CANNOT RULE OUT A BRIEF PERIOD OF
IFR...ESPECIALLY AT RST...BUT CONFIDENCE TOO LOW TO INCLUDE. A
COUPLE OF THUNDERSTORMS MAY OCCUR AS WELL...BUT CONFIDENCE HAS
LOWERED A LOT ABOUT THEM IMPACTING THE TAF SITES...THEREFORE THE
TSRA HAS BEEN REMOVED FROM THE TAFS. PLAN ON CEILINGS TO CLIMB
BACK UP TO VFR DURING THE EVENING AS DRY AIR FILTERS IN.
3. POTENTIAL FOR VALLEY FOG LATE TONIGHT AT LSE. RAINFALL TODAY
COMBINED WITH CLEARING IN THE EVENING...COOLING TEMPERATURES AND
WINDS BECOMING LIGHT WITHIN THE VALLEYS COULD ALLOW FOR FOG
FORMATION. HOWEVER...DEPTH/TIMING OF THE LIGHT WINDS AS WELL AS
POTENTIAL FOR DRY AIR TO MOVE IN RESULT IN LOW CONFIDENCE OF
MENTIONING FOG IN THE LSE TAF AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
508 PM CDT SAT SEP 28 2013
.DISCUSSION...
254 PM CDT
MAIN CONCERNS TODAY REVOLVE AROUND TIMING PRECIPITATION ASSOCIATED
WITH A COLD FRONT SWEEPING ACROSS THE REGION THIS EVENING.
THIS EVENING AND TONIGHT...
A COLD FRONT SPANS FROM THE ARROWHEAD OF MINNESOTA SOUTH INTO
EASTERN IOWA THIS AFTERNOON WITH PRECIP GENERALLY OCCURRING ALONG
AND JUST AHEAD OF THIS SYSTEM. LIGHTNING ACTIVITY WAS CONFINED
MAINLY TO MISSOURI...BUT HAS REALLY DISSIPATED OVER THE PAST FEW
HOURS. LATEST RAP GUIDANCE DOES INDICATE POTENTIALLY A LITTLE MORE
ROBUST INSTABILITY THAN PREVIOUSLY THOUGHT THOUGH...AND ACCAS OVER THE
AREA THIS MORNING WOULD ALSO SUGGEST THE PRESENCE OF SOME MID LEVEL
INSTABILITY...SO WILL MAINTAIN AT LEAST A SLIGHT CHANCE MENTION FOR
THUNDERSTORMS TODAY THOUGH MAINLY EXPECT RAIN WITH A FEW EMBEDDED
MODERATE SHOWERS. WHILE THERMODYNAMICALLY UNIMPRESSIVE...DYNAMIC
FORCING THIS EVENT CONTINUES TO LEAD TO HIGH CONFIDENCE IN THE
ENTIRE CWA SEEING WETTING RAINS THIS EVENING. WATER VAPOR IMAGERY
SHOWS A WELL DEFINED NEGATIVELY TILTED VORT MAX LIFTING ACROSS THE
UPPER MIDWEST WITH DEEP MOISTURE EXTENDING SOUTH ALONG THE FRONT.
PWATS COULD BE PUSHING 2 INCHES ALONG THE FRONT AS IT SWEEPS ACROSS
THE REGION TONIGHT. WHILE THE BEST UPPER LEVEL FORCING LIES NORTH OF
THE AREA...STILL EXPECT DECENT HEIGHT FALLS TO SPREAD OVER NORTHERN
ILLINOIS...ESPECIALLY LATE THIS EVENING. NAM/GFS INDICATE COUPLED
JET WITH THE BEST AREA OF DIVERGENCE ALOFT MOVING DIRECTLY OVERHEAD
THIS EVENING. THESE COUPLED WITH THE STRONG LOW LEVEL CONVERGENCE
ALONG THE FRONT SHOULD LEAD TO A DEEP VERTICAL RESPONSE...WITH
ACTIVITY ALONG THE FRONT INCREASING IN COVERAGE/INTENSITY LATE THIS
EVENING AS THE FRONT MOVES ACROSS THE CENTRAL AND EASTERN PORTIONS
OF THE CWA.
SUNDAY THROUGH TUESDAY...
FLAT RIDGING WILL BUILD OVER THE LOCAL AREA THROUGH THIS PERIOD WITH
THE MAIN JET STREAM SETTING UP FROM THE PACIFIC NORTHWEST INTO THE
NORTHERN GREAT LAKES...RESULTING IN DRY WEATHER WITH PRECIP CHANCES
STAYING NORTH OF THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING COLD FRONT SUNDAY. NORTH/NORTHEAST WINDS
SUNDAY WILL KEEP CONDITIONS QUITE A BIT COOLER NEAR THE LAKE FRONT
SUNDAY...LIKELY IN THE MID 60S...BUT TEMPERATURES FARTHER INLAND
SHOULD BE ABLE TO RISE INTO THE LOW TO MID 70S. CLEAR SKIES AND CALM
WINDS UNDER THE RIDGE AXIS SUNDAY NIGHT WILL ALLOW TEMPERATURES TO
EFFECTIVELY RADIATE WITH OVERNIGHT LOWS EXPECTED IN THE LOW TO MID
40S OUTSIDE OF URBAN HEAT ISLAND OF CHICAGO...WHICH IS EXPECTED TO
STAY PROPPED INTO THE MID 50S. WOULDNT BE SURPRISED IF SOME OF THE
TYPICAL COLD SPOTS DIP INTO THE 30S. WILL HAVE TO KEEP AN EYE ON FOG
SUNDAY NIGHT...BUT FOR NOW GUIDANCE SUGGESTS THAT DEW POINTS MAY BE
TOO DRY FOR WIDESPREAD FOG DEVELOP. WITH RECENT RAINFALL
THOUGH...NOT CONFIDENT THAT MODELS ARE HANDLING LOW LEVEL MOISTURE
VERY WELL. WILL INCLUDE MENTION FOR PATCHY FOG OUTSIDE THE METRO
AREA.
WITH THE RIDGE AXIS GRADUALLY SHIFTING EAST OF THE AREA
ON MONDAY...RETURN FLOW WILL LEAD TO A WARMING TREND WITH MID TO
UPPER 70S MONDAY...AND 80S POSSIBLE AGAIN BY TUESDAY. GFS/EMCWF BOTH
SHOW THERMAL RIDGE LEANING OVER THE REGION TUESDAY WITH H85 TEMPS A
LITTLE WARMER THAN TODAY IN THE 16-18C RANGE...THOUGH IF RECENT
MODEL PERFORMANCE IS ANY INDICATOR...THIS MAY BE A BIT TOO WARM.
EVEN TAKING A CONSERVATIVE APPROACH...GUIDANCE APPEARS TO BE A BIT
ON THE COOL SIDE SO WILL MAINTAIN THE WARMER FORECAST OF LOW TO MID
80S.
WEDNESDAY THROUGH SATURDAY...
MODELS IN DECENT AGREEMENT THROUGH WEDNESDAY...WITH THE DEVELOPMENT
OF A DEEP TROUGH OVER THE WEST COAST WEDNESDAY NIGHT...THEN BEGIN TO
DIVERGE WITH TIMING/STRENGTH INTO THE WEEKEND. THE UPPER TROUGH IS
EXPECTED TO PROGRESS EAST ACROSS THE ROCKIES...WITH SURFACE LOW
DEVELOPING OVER THE PLAINS AND A WARM FRONT LIFTING NORTH ACROSS THE
LOCAL AREA. TIMING IS THE MAIN ISSUE. THE GFS IS FASTEST...FOLLOWED
BY THE ECMWF AND THEN THE GFS ENSEMBLE MEAN. A SPAGHETTI PLOT OF
GEFS MEMBERS SHOWING SIGNIFICANT SPREAD BY FRIDAY EVENING...WITH THE
MOST PROGRESSIVE MEMBER SHOWING THE TROUGH AXIS NEARING THE
MISSISSIPPI VALLEY BY FRIDAY EVENING...WHILE SLOWEST MEMBERS HAVE A
DEEPER CLOSED LOW STILL OVER THE INTERMOUNTAIN WEST. ALL THIS BOILS
DOWN TO VERY LOW CONFIDENCE IN THE EXTENDED...THUS MAINTAINED A
BLENDED MODEL SOLUTION IN THE EXTENDED FORECAST...UNTIL DETAILS
START TO BECOME MORE CLEAR.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SSW WINDS GUSTING 35-18 KT AT TIMES FOR THE NEXT FEW HOURS WITH
GUSTS DIMINISHING TOWARD/AFTER 00Z.
* LIGHT RAIN SHOWERS ARRIVE AROUND 00Z...WITH STEADIER RAIN
EXPECTED TOWARD/AFTER 03Z...WITH REDUCED VSBY. SHRA COVERAGE
SHOULD DECREASE AFTER 05Z.
* COLD FRONT PASSES AROUND 05Z SHIFTING WINDS TO NW.
* MVFR CIGS ARRIVING MID EVENING THEN EXIT OVERNIGHT.
MDB
//DISCUSSION...UPDATED 22Z...
HAVE MADE A FEW ADJUSTMENTS TO THE TAFS TO BETTER TIME RAIN
CHANCES AND WIND GUSTS. DIMINISHING BAND OF RAIN CONTINUES TO
MARCH EASTWARD ACROSS NORTH CENTRAL IL OUT AHEAD OF A COLD FRONT
WHICH IS JUST NOW APPROACHING THE THE WESTERN FRINGE OF THE QUAD
CITIES. THIS WILL BRING SOME LIGHT SHOWERS TO THE TERMINALS OVER
THE NEXT FEW HOURS. RAIN COVERAGE IS EXPECTED TO EXPAND EARLY
THIS EVENING TO THE SOUTHWEST OF THE TERMINALS AS BETTER FORCING
ARRIVES COMBINING WITH THE FRONT WHICH WILL BE MOVING CLOSER TO
THE AREA. THIS RAIN IS THEN EXPECTED TO MOVE ACROSS THE
TERMINALS. HAVE PUSHED BACK PERIOD OF BETTER ORGANIZED PRECIP AND
LOWER VSBY/CIG MENTION IN THE TAFS BY A FEW HOURS TO LINE UP WITH
THIS EXPECTATION. RFD MAY HAVE THE BEST CHANCE OF SEEING LESS RAIN
THIS EVENING AS THE BULK OF NEW DEVELOPMENT MAY BE JUST TO THEIR
SOUTH AND EAST...SO FURTHER TAF ADJUSTMENTS MAY BE NECESSARY. THE
FRONT WILL CROSS THE AREA AND FORCING BEHIND IT MAY ALLOW SOME
SCATTERED SHOWERS TO LINGER FOR 1-2 HOURS AFTER IT PASSES...WITH
LOWER END MVFR CIGS ALSO LINGERING BEHIND THE FRONT...THOUGH
THINGS SHOULD QUICKLY CLEAR AFTER THAT. THE PRESSURE GRADIENT JUST
AHEAD OF THE FRONT REMAINS FAIRLY WELL ORGANIZED SO EXPECT THAT
SOME GUSTINESS WILL CONTINUE THOUGH THE MAGNITUDE SHOULD DECREASE
INTO THE 15-20 KT RANGE. WINDS WILL SHIFT NORTHWEST BEHIND THE
FRONT WITH SOME SPORADIC GUSTS POSSIBLE BEFORE WINDS DIMINISH
LATER TONIGHT.
MDB
FROM 18Z...
ABUNDANT SUNSHINE WITH VFR CONDS WILL CONTINUE THRU THIS
AFTN...PRIOR TO THE FRONTAL BOUNDARY APPROACHING FROM THE WEST.
THIS AFTN A LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS
EXTENDS ALONG THE BOUNDARY IN EASTERN IOWA STRETCHING SOUTH
THROUGH EASTERN MISSOURI. GUIDANCE CONTINUES TO SLOWLY BRING THIS
BNDRY EAST TOWARDS RFD ARND 02-04Z...THEN CONTINUES TO PROGRESS
EAST THROUGH THE EVENING/OVERNIGHT. THE GUSTY WINDS FROM THE SOUTH
TO 25KT WILL QUICKLY DIMINISH ONCE THE THICKER CLOUD COVER ARRIVES
LATE THIS AFTN/EARLY EVE WITH SPEEDS GENERALLY ARND 10-12KT. THEN
POST FRONTAL PASSAGE WINDS WILL QUICKLY VEER TO THE NORTHWEST BTWN
07-10Z. WITH THE STEADIER PRECIP CIGS MAY DIP TO BORDERLINE
MVFR/VFR CONDS ARND 2500FT AGL. WITH THE QUICK SHIFT IN WINDS
BEHIND THE BNDRY...CIGS SHUD QUICKLY THIN AND LIFT ALONG WITH THE
DRIER AIR THAT WILL PUSH OVERHEAD.
WINDS TURN NORTHWEST THEN NORTHEAST ARND DAYBREAK SUN...WITH
SPEEDS GENERALLY HOVERING ARND 09-12KT THROUGH THIS PERIOD. VFR
CONDS WILL PREVAIL THRU MUCH OF SUN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND TRENDS THROUGH SUNSET.
* HIGH CONFIDENCE IN LIGHT RAIN SHOWERS ARRIVING BY ABOUT 00Z
...MEDIUM-HIGH CONFIDENCE IN STEADIER/HEAVIER RAIN ARRIVING MID
EVENING...MEDIUM CONFIDENCE IN TIMING. MEDIUM CONFIDENCE IN
SHOWERS LINGERING AFTER 05/06Z.
* HIGH CONFIDENCE IN TIMING OF COLD FRONTAL PASSAGE.
* HIGH CONFIDENCE IN A PERIOD OF MVFR CIGS STARTING MID
EVENING...MEDIUM CONFIDENCE IN TIMING OF ARRIVAL AND DEPARTURE.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
THURSDAY NIGHT AND FRIDAY...CHANCE SHRA/TSRA.
IZZI
&&
.MARINE...
220 PM CDT
HIGH PRESSURE IS OVER NEW ENGLAND WHILE A LOW IS OVER NORTHERN
MINNESOTA/SOUTHWEST ONTARIO. WINDS HAVE STRUGGLED TO STRENGTHEN
OVER THE LAKE TODAY...BUT ARE FINALLY STARTING TO PICK UP. WILL
KEEP THE SMALL CRAFT ADVISORY GOING AND END IT AT 7PM TONIGHT AS
PLANNED. THE HIGH SLOWLY SHIFTS OFF THE NE ATLANTIC COAST WHILE THE
LOW REACHES HUDSON BAY TOMORROW. GUIDANCE IS STILL SUGGESTING WINDS
WILL PICK UP TO 30KT THIS EVENING OVER THE NORTH HALF TO THE LAKE.
IN ADDITION...SOUNDINGS STILL INDICATE THAT GALE FORCE GUSTS LIE
JUST 200 FT ABOVE THE SURFACE. WILL KEEP OCNL GALE FORCE GUSTS GOING
THROUGH 03Z AND HIGHER VESSELS WILL PROBABLY ENCOUNTER MORE THAN
JUST OCNL GALE FORCE GUSTS.
THE LOWS COLD FRONT SWEEPS OVER THE LAKE LATE THIS EVENING WITH NW
WINDS 15-20 KT BEHIND IT. A WEAK SURFACE RIDGE MOVES OVER THE LAKE
TOMORROW AND WINDS QUICKLY DIMINISH. THE HIGH PUSHES EAST WITH
SOUTH WINDS EXPECTED ACROSS THE LAKE MONDAY AND TUESDAY. ANOTHER
LOW PASSES OVER THE SOUTHERN CANADIAN PRAIRIES EARLY NEXT WEEK...AND
EXPECTING THE PRESSURE GRADIENT TO TIGHTEN OVER THE NORTHERN HALF OF
THE LAKE. THEREFORE...HAVE 30KT WINDS OVER THE NORTHERN HALF OF THE
LAKE MONDAY NIGHT AND TUESDAY. WINDS TURN WEST AS THE LOW PUSHES
EAST AND ANOTHER WEAK SURFACE RIDGE SETS UP OVER THE LAKE.
LATE NEXT WEEK STILL LOOKS INTERESTING WITH A LARGE LOW CROSSING THE
PLAINS AND PASSING OVER LAKE SUPERIOR. MODEL TIMING IS NOT
CONSISTENT BETWEEN THE MODELS AND MODEL RUNS. THAT BEING SAID
GUIDANCE IS STILL SUGGESTING STRONG SOUTH WINDS LATE NEXT WEEK AHEAD
OF THE LOW.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 7 PM SATURDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
309 PM CDT SAT SEP 28 2013
.DISCUSSION...
254 PM CDT
MAIN CONCERNS TODAY REVOLVE AROUND TIMING PRECIPITATION ASSOCIATED
WITH A COLD FRONT SWEEPING ACROSS THE REGION THIS EVENING.
THIS EVENING AND TONIGHT...
A COLD FRONT SPANS FROM THE ARROWHEAD OF MINNESOTA SOUTH INTO
EASTERN IOWA THIS AFTERNOON WITH PRECIP GENERALLY OCCURRING ALONG
AND JUST AHEAD OF THIS SYSTEM. LIGHTNING ACTIVITY WAS CONFINED
MAINLY TO MISSOURI...BUT HAS REALLY DISSIPATED OVER THE PAST FEW
HOURS. LATEST RAP GUIDANCE DOES INDICATE POTENTIALLY A LITTLE MORE
ROBUST INSTABILITY THAN PREVIOUSLY THOUGHT THOUGH...AND ACCAS OVER THE
AREA THIS MORNING WOULD ALSO SUGGEST THE PRESENCE OF SOME MID LEVEL
INSTABILITY...SO WILL MAINTAIN AT LEAST A SLIGHT CHANCE MENTION FOR
THUNDERSTORMS TODAY THOUGH MAINLY EXPECT RAIN WITH A FEW EMBEDDED
MODERATE SHOWERS. WHILE THERMODYNAMICALLY UNIMPRESSIVE...DYNAMIC
FORCING THIS EVENT CONTINUES TO LEAD TO HIGH CONFIDENCE IN THE
ENTIRE CWA SEEING WETTING RAINS THIS EVENING. WATER VAPOR IMAGERY
SHOWS A WELL DEFINED NEGATIVELY TILTED VORT MAX LIFTING ACROSS THE
UPPER MIDWEST WITH DEEP MOISTURE EXTENDING SOUTH ALONG THE FRONT.
PWATS COULD BE PUSHING 2 INCHES ALONG THE FRONT AS IT SWEEPS ACROSS
THE REGION TONIGHT. WHILE THE BEST UPPER LEVEL FORCING LIES NORTH OF
THE AREA...STILL EXPECT DECENT HEIGHT FALLS TO SPREAD OVER NORTHERN
ILLINOIS...ESPECIALLY LATE THIS EVENING. NAM/GFS INDICATE COUPLED
JET WITH THE BEST AREA OF DIVERGENCE ALOFT MOVING DIRECTLY OVERHEAD
THIS EVENING. THESE COUPLED WITH THE STRONG LOW LEVEL CONVERGENCE
ALONG THE FRONT SHOULD LEAD TO A DEEP VERTICAL RESPONSE...WITH
ACTIVITY ALONG THE FRONT INCREASING IN COVERAGE/INTENSITY LATE THIS
EVENING AS THE FRONT MOVES ACROSS THE CENTRAL AND EASTERN PORTIONS
OF THE CWA.
SUNDAY THROUGH TUESDAY...
FLAT RIDGING WILL BUILD OVER THE LOCAL AREA THROUGH THIS PERIOD WITH
THE MAIN JET STREAM SETTING UP FROM THE PACIFIC NORTHWEST INTO THE
NORTHERN GREAT LAKES...RESULTING IN DRY WEATHER WITH PRECIP CHANCES
STAYING NORTH OF THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING COLD FRONT SUNDAY. NORTH/NORTHEAST WINDS
SUNDAY WILL KEEP CONDITIONS QUITE A BIT COOLER NEAR THE LAKE FRONT
SUNDAY...LIKELY IN THE MID 60S...BUT TEMPERATURES FARTHER INLAND
SHOULD BE ABLE TO RISE INTO THE LOW TO MID 70S. CLEAR SKIES AND CALM
WINDS UNDER THE RIDGE AXIS SUNDAY NIGHT WILL ALLOW TEMPERATURES TO
EFFECTIVELY RADIATE WITH OVERNIGHT LOWS EXPECTED IN THE LOW TO MID
40S OUTSIDE OF URBAN HEAT ISLAND OF CHICAGO...WHICH IS EXPECTED TO
STAY PROPPED INTO THE MID 50S. WOULDNT BE SURPRISED IF SOME OF THE
TYPICAL COLD SPOTS DIP INTO THE 30S. WILL HAVE TO KEEP AN EYE ON FOG
SUNDAY NIGHT...BUT FOR NOW GUIDANCE SUGGESTS THAT DEW POINTS MAY BE
TOO DRY FOR WIDESPREAD FOG DEVELOP. WITH RECENT RAINFALL
THOUGH...NOT CONFIDENT THAT MODELS ARE HANDLING LOW LEVEL MOISTURE
VERY WELL. WILL INCLUDE MENTION FOR PATCHY FOG OUTSIDE THE METRO
AREA.
WITH THE RIDGE AXIS GRADUALLY SHIFTING EAST OF THE AREA
ON MONDAY...RETURN FLOW WILL LEAD TO A WARMING TREND WITH MID TO
UPPER 70S MONDAY...AND 80S POSSIBLE AGAIN BY TUESDAY. GFS/EMCWF BOTH
SHOW THERMAL RIDGE LEANING OVER THE REGION TUESDAY WITH H85 TEMPS A
LITTLE WARMER THAN TODAY IN THE 16-18C RANGE...THOUGH IF RECENT
MODEL PERFORMANCE IS ANY INDICATOR...THIS MAY BE A BIT TOO WARM.
EVEN TAKING A CONSERVATIVE APPROACH...GUIDANCE APPEARS TO BE A BIT
ON THE COOL SIDE SO WILL MAINTAIN THE WARMER FORECAST OF LOW TO MID
80S.
WEDNESDAY THROUGH SATURDAY...
MODELS IN DECENT AGREEMENT THROUGH WEDNESDAY...WITH THE DEVELOPMENT
OF A DEEP TROUGH OVER THE WEST COAST WEDNESDAY NIGHT...THEN BEGIN TO
DIVERGE WITH TIMING/STRENGTH INTO THE WEEKEND. THE UPPER TROUGH IS
EXPECTED TO PROGRESS EAST ACROSS THE ROCKIES...WITH SURFACE LOW
DEVELOPING OVER THE PLAINS AND A WARM FRONT LIFTING NORTH ACROSS THE
LOCAL AREA. TIMING IS THE MAIN ISSUE. THE GFS IS FASTEST...FOLLOWED
BY THE ECMWF AND THEN THE GFS ENSEMBLE MEAN. A SPAGHETTI PLOT OF
GEFS MEMBERS SHOWING SIGNIFICANT SPREAD BY FRIDAY EVENING...WITH THE
MOST PROGRESSIVE MEMBER SHOWING THE TROUGH AXIS NEARING THE
MISSISSIPPI VALLEY BY FRIDAY EVENING...WHILE SLOWEST MEMBERS HAVE A
DEEPER CLOSED LOW STILL OVER THE INTERMOUNTAIN WEST. ALL THIS BOILS
DOWN TO VERY LOW CONFIDENCE IN THE EXTENDED...THUS MANINTAINED A
BLENDED MODEL SOLUTION IN THE EXTENDED FORECAST...UNTIL DETAILS
START TO BECOME MORE CLEAR.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* BREEZY SOUTH WINDS CONTINUE AROUND 15-18KT WITH GUSTS TO 28KT
THRU LATE THIS AFTN. SPEEDS WILL QUICKLY DECREASE WITH THICKER
CLOUD COVER ARRIVING AFT 23Z.
* PRECIP ARRIVES ARND 0-2Z WITH THE MORE STEADY RAIN AND POSSIBLY
A RUMBLE OF THUNDER ARND 2-4Z. THEN ALL PRECIP SHUD COME TO AN
END ARND 6Z. PSBL PERIOD OF MVFR CIGS WITH STEADIER PRECIP.
* FRONTAL PASSAGE ARND 6Z WITH WINDS QUICKLY VEERING NORTHWEST
AND SPEEDS DECREASING TO ARND 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ABUNDANT SUNSHINE WITH VFR CONDS WILL CONTINUE THRU THIS
AFTN...PRIOR TO THE FRONTAL BOUNDARY APPROACHING FROM THE WEST.
THIS AFTN A LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS
EXTENDS ALONG THE BOUNDARY IN EASTERN IOWA STRETCHING SOUTH
THROUGH EASTERN MISSOURI. GUIDANCE CONTINUES TO SLOWLY BRING THIS
BNDRY EAST TOWARDS RFD ARND 02-04Z...THEN CONTINUES TO PROGRESS
EAST THROUGH THE EVENING/OVERNIGHT. THE GUSTY WINDS FROM THE SOUTH
TO 25KT WILL QUICKLY DIMINISH ONCE THE THICKER CLOUD COVER ARRIVES
LATE THIS AFTN/EARLY EVE WITH SPEEDS GENERALLY ARND 10-12KT. THEN
POST FRONTAL PASSAGE WINDS WILL QUICKLY VEER TO THE NORTHWEST BTWN
07-10Z. WITH THE STEADIER PRECIP CIGS MAY DIP TO BORDERLINE
MVFR/VFR CONDS ARND 2500FT AGL. WITH THE QUICK SHIFT IN WINDS
BEHIND THE BNDRY...CIGS SHUD QUICKLY THIN AND LIFT ALONG WITH THE
DRIER AIR THAT WILL PUSH OVERHEAD.
WINDS TURN NORTHWEST THEN NORTHEAST ARND DAYBREAK SUN...WITH
SPEEDS GENERALLY HOVERING ARND 09-12KT THROUGH THIS PERIOD. VFR
CONDS WILL PREVAIL THRU MUCH OF SUN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS THRU 23Z...THEN
MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEEDS.
* MEDIUM CONFIDECE IN PRECISE TIME OF WIND SHIFT AND SPEEDS
THROUGH FRONTAL PASSAGE.
* HIGH CONFIDENCE IN PRECIP ARRIVING AT ORD/MDW. MEDIUM CONFIDENCE
IN PRECISE TIME OF PRECIP ARRIVAL AND DURATION.
* HIGH CONFIDENCE IN PRECIP ENDING BY 08Z SUN.
* HIGH CONFIDENCE IN VFR CONDS AND LGT N/NE WINDS DEVELOPING BY
12Z SUN.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
THURSDAY NIGHT AND FRIDAY...CHANCE SHRA/TSRA.
IZZI
&&
.MARINE...
220 PM CDT
HIGH PRESSURE IS OVER NEW ENGLAND WHILE A LOW IS OVER NORTHERN
MINNESOTA/SOUTHWEST ONTARIO. WINDS HAVE STRUGGLED TO STRENGTHEN
OVER THE LAKE TODAY...BUT ARE FINALLY STARTING TO PICK UP. WILL
KEEP THE SMALL CRAFT ADVISORY GOING AND END IT AT 7PM TONIGHT AS
PLANNED. THE HIGH SLOWLY SHIFTS OFF THE NE ATLANTIC COAST WHILE THE
LOW REACHES HUDSON BAY TOMORROW. GUIDANCE IS STILL SUGGESTING WINDS
WILL PICK UP TO 30KT THIS EVENING OVER THE NORTH HALF TO THE LAKE.
IN ADDITION...SOUNDINGS STILL INDICATE THAT GALE FORCE GUSTS LIE
JUST 200 FT ABOVE THE SURFACE. WILL KEEP OCNL GALE FORCE GUSTS GOING
THROUGH 03Z AND HIGHER VESSELS WILL PROBABLY ENCOUNTER MORE THAN
JUST OCNL GALE FORCE GUSTS.
THE LOWS COLD FRONT SWEEPS OVER THE LAKE LATE THIS EVENING WITH NW
WINDS 15-20 KT BEHIND IT. A WEAK SURFACE RIDGE MOVES OVER THE LAKE
TOMORROW AND WINDS QUICKLY DIMINISH. THE HIGH PUSHES EAST WITH
SOUTH WINDS EXPECTED ACROSS THE LAKE MONDAY AND TUESDAY. ANOTHER
LOW PASSES OVER THE SOUTHERN CANADIAN PRAIRIES EARLY NEXT WEEK...AND
EXPECTING THE PRESSURE GRADIENT TO TIGHTEN OVER THE NORTHERN HALF OF
THE LAKE. THEREFORE...HAVE 30KT WINDS OVER THE NORTHERN HALF OF THE
LAKE MONDAY NIGHT AND TUESDAY. WINDS TURN WEST AS THE LOW PUSHES
EAST AND ANOTHER WEAK SURFACE RIDGE SETS UP OVER THE LAKE.
LATE NEXT WEEK STILL LOOKS INTERESTING WITH A LARGE LOW CROSSING THE
PLAINS AND PASSING OVER LAKE SUPERIOR. MODEL TIMING IS NOT
CONSISTENT BETWEEN THE MODELS AND MODEL RUNS. THAT BEING SAID
GUIDANCE IS STILL SUGGESTING STRONG SOUTH WINDS LATE NEXT WEEK AHEAD
OF THE LOW.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 PM SATURDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT SAT SEP 28 2013
.DISCUSSION...
254 PM CDT
MAIN CONCERNS TODAY REVOLVE AROUND TIMING PRECIPITATION ASSOCIATED
WITH A COLD FRONT SWEEPING ACROSS THE REGION THIS EVENING.
THIS EVENING AND TONIGHT...
A COLD FRONT SPANS FROM THE ARROWHEAD OF MINNESOTA SOUTH INTO
EASTERN IOWA THIS AFTERNOON WITH PRECIP GENERALLY OCCURRING ALONG
AND JUST AHEAD OF THIS SYSTEM. LIGHTNING ACTIVITY WAS CONFINED
MAINLY TO MISSOURI...BUT HAS REALLY DISSIPATED OVER THE PAST FEW
HOURS. LATEST RAP GUIDANCE DOES INDICATE POTENTIALLY A LITTLE MORE
ROBUST INSTABILITY THAN PREVIOUSLY THOUGHT THOUGH...AND ACCAS OVER THE
AREA THIS MORNING WOULD ALSO SUGGEST THE PRESENCE OF SOME MID LEVEL
INSTABILITY...SO WILL MAINTAIN AT LEAST A SLIGHT CHANCE MENTION FOR
THUNDERSTORMS TODAY THOUGH MAINLY EXPECT RAIN WITH A FEW EMBEDDED
MODERATE SHOWERS. WHILE THERMODYNAMICALLY UNIMPRESSIVE...DYNAMIC
FORCING THIS EVENT CONTINUES TO LEAD TO HIGH CONFIDENCE IN THE
ENTIRE CWA SEEING WETTING RAINS THIS EVENING. WATER VAPOR IMAGERY
SHOWS A WELL DEFINED NEGATIVELY TILTED VORT MAX LIFTING ACROSS THE
UPPER MIDWEST WITH DEEP MOISTURE EXTENDING SOUTH ALONG THE FRONT.
PWATS COULD BE PUSHING 2 INCHES ALONG THE FRONT AS IT SWEEPS ACROSS
THE REGION TONIGHT. WHILE THE BEST UPPER LEVEL FORCING LIES NORTH OF
THE AREA...STILL EXPECT DECENT HEIGHT FALLS TO SPREAD OVER NORTHERN
ILLINOIS...ESPECIALLY LATE THIS EVENING. NAM/GFS INDICATE COUPLED
JET WITH THE BEST AREA OF DIVERGENCE ALOFT MOVING DIRECTLY OVERHEAD
THIS EVENING. THESE COUPLED WITH THE STRONG LOW LEVEL CONVERGENCE
ALONG THE FRONT SHOULD LEAD TO A DEEP VERTICAL RESPONSE...WITH
ACTIVITY ALONG THE FRONT INCREASING IN COVERAGE/INTENSITY LATE THIS
EVENING AS THE FRONT MOVES ACROSS THE CENTRAL AND EASTERN PORTIONS
OF THE CWA.
SUNDAY THROUGH TUESDAY...
FLAT RIDGING WILL BUILD OVER THE LOCAL AREA THROUGH THIS PERIOD WITH
THE MAIN JET STREAM SETTING UP FROM THE PACIFIC NORTHWEST INTO THE
NORTHERN GREAT LAKES...RESULTING IN DRY WEATHER WITH PRECIP CHANCES
STAYING NORTH OF THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING COLD FRONT SUNDAY. NORTH/NORTHEAST WINDS
SUNDAY WILL KEEP CONDITIONS QUITE A BIT COOLER NEAR THE LAKE FRONT
SUNDAY...LIKELY IN THE MID 60S...BUT TEMPERATURES FARTHER INLAND
SHOULD BE ABLE TO RISE INTO THE LOW TO MID 70S. CLEAR SKIES AND CALM
WINDS UNDER THE RIDGE AXIS SUNDAY NIGHT WILL ALLOW TEMPERATURES TO
EFFECTIVELY RADIATE WITH OVERNIGHT LOWS EXPECTED IN THE LOW TO MID
40S OUTSIDE OF URBAN HEAT ISLAND OF CHICAGO...WHICH IS EXPECTED TO
STAY PROPPED INTO THE MID 50S. WOULDNT BE SURPRISED IF SOME OF THE
TYPICAL COLD SPOTS DIP INTO THE 30S. WILL HAVE TO KEEP AN EYE ON FOG
SUNDAY NIGHT...BUT FOR NOW GUIDANCE SUGGESTS THAT DEW POINTS MAY BE
TOO DRY FOR WIDESPREAD FOG DEVELOP. WITH RECENT RAINFALL
THOUGH...NOT CONFIDENT THAT MODELS ARE HANDLING LOW LEVEL MOISTURE
VERY WELL. WILL INCLUDE MENTION FOR PATCHY FOG OUTSIDE THE METRO
AREA.
WITH THE RIDGE AXIS GRADUALLY SHIFTING EAST OF THE AREA
ON MONDAY...RETURN FLOW WILL LEAD TO A WARMING TREND WITH MID TO
UPPER 70S MONDAY...AND 80S POSSIBLE AGAIN BY TUESDAY. GFS/EMCWF BOTH
SHOW THERMAL RIDGE LEANING OVER THE REGION TUESDAY WITH H85 TEMPS A
LITTLE WARMER THAN TODAY IN THE 16-18C RANGE...THOUGH IF RECENT
MODEL PERFORMANCE IS ANY INDICATOR...THIS MAY BE A BIT TOO WARM.
EVEN TAKING A CONSERVATIVE APPROACH...GUIDANCE APPEARS TO BE A BIT
ON THE COOL SIDE SO WILL MAINTAIN THE WARMER FORECAST OF LOW TO MID
80S.
WEDNESDAY THROUGH SATURDAY...
MODELS IN DECENT AGREEMENT THROUGH WEDNESDAY...WITH THE DEVELOPMENT
OF A DEEP TROUGH OVER THE WEST COAST WEDNESDAY NIGHT...THEN BEGIN TO
DIVERGE WITH TIMING/STRENGTH INTO THE WEEKEND. THE UPPER TROUGH IS
EXPECTED TO PROGRESS EAST ACROSS THE ROCKIES...WITH SURFACE LOW
DEVELOPING OVER THE PLAINS AND A WARM FRONT LIFTING NORTH ACROSS THE
LOCAL AREA. TIMING IS THE MAIN ISSUE. THE GFS IS FASTEST...FOLLOWED
BY THE ECMWF AND THEN THE GFS ENSEMBLE MEAN. A SPAGHETTI PLOT OF
GEFS MEMBERS SHOWING SIGNIFICANT SPREAD BY FRIDAY EVENING...WITH THE
MOST PROGRESSIVE MEMBER SHOWING THE TROUGH AXIS NEARING THE
MISSISSIPPI VALLEY BY FRIDAY EVENING...WHILE SLOWEST MEMBERS HAVE A
DEEPER CLOSED LOW STILL OVER THE INTERMOUNTAIN WEST. ALL THIS BOILS
DOWN TO VERY LOW CONFIDENCE IN THE EXTENDED...THUS MANINTAINED A
BLENDED MODEL SOLUTION IN THE EXTENDED FORECAST...UNTIL DETAILS
START TO BECOME MORE CLEAR.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTH WINDS INCREASING WITH SPEEDS ARND 15-18KT AND GUSTS UP TO
25KT THRU LATE THIS AFTN. SPEEDS WILL QUICKLY DECREASE WITH
THICKER CLOUD COVER ARRIVING AFT 23Z.
* PRECIP ARRIVES ARND 3Z WITH THE MORE STEADY RAIN AND POSSIBLY A
RUMBLE OF THUNDER ARND 4-6Z. THEN ALL PRECIP SHUD COME TO AN END
ARND 8-9Z. PSBL PERIOD OF MVFR CIGS WITH STEADIER PRECIP.
* FRONTAL PASSAGE ARND 6-9Z WITH WINDS QUICKLY VEERING NORTHWEST
AND SPEEDS DECREASING TO ARND 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ABUNDANT SUNSHINE WITH VFR CONDS WILL CONTINUE THRU THIS
AFTN...PRIOR TO THE FRONTAL BOUNDARY APPROACHING FROM THE WEST.
THIS AFTN A LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS
EXTENDS ALONG THE BOUNDARY IN EASTERN IOWA STRETCHING SOUTH
THROUGH EASTERN MISSOURI. GUIDANCE CONTINUES TO SLOWLY BRING THIS
BNDRY EAST TOWARDS RFD ARND 02-04Z...THEN CONTINUES TO PROGRESS
EAST THROUGH THE EVENING/OVERNIGHT. THE GUSTY WINDS FROM THE SOUTH
TO 25KT WILL QUICKLY DIMINISH ONCE THE THICKER CLOUD COVER ARRIVES
LATE THIS AFTN/EARLY EVE WITH SPEEDS GENERALLY ARND 10-12KT. THEN
POST FRONTAL PASSAGE WINDS WILL QUICKLY VEER TO THE NORTHWEST BTWN
07-10Z. WITH THE STEADIER PRECIP CIGS MAY DIP TO BORDERLINE
MVFR/VFR CONDS ARND 2500FT AGL. WITH THE QUICK SHIFT IN WINDS
BEHIND THE BNDRY...CIGS SHUD QUICKLY THIN AND LIFT ALONG WITH THE
DRIER AIR THAT WILL PUSH OVERHEAD.
WINDS TURN NORTHWEST THEN NORTHEAST ARND DAYBREAK SUN...WITH
SPEEDS GENERALLY HOVERING ARND 09-12KT THROUGH THIS PERIOD. VFR
CONDS WILL PREVAIL THRU MUCH OF SUN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS THRU 23Z...THEN
MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEEDS.
* MEDIUM CONFIDECE IN PRECISE TIME OF WIND SHIFT AND SPEEDS
THROUGH FRONTAL PASSAGE.
* HIGH CONFIDENCE IN PRECIP ARRIVING AT ORD/MDW. MEDIUM CONFIDENCE
IN PRECISE TIME OF PRECIP ARRIVAL AND DURATION.
* HIGH CONFIDENCE IN PRECIP ENDING BY 08Z SUN.
* HIGH CONFIDENCE IN VFR CONDS AND LGT N/NE WINDS DEVELOPING BY
12Z SUN.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
THURSDAY NIGHT AND FRIDAY...CHANCE SHRA/TSRA.
IZZI
&&
.MARINE...
220 PM CDT
HIGH PRESSURE IS OVER NEW ENGLAND WHILE A LOW IS OVER NORTHERN
MINNESOTA/SOUTHWEST ONTARIO. WINDS HAVE STRUGGLED TO STRENGTHEN
OVER THE LAKE TODAY...BUT ARE FINALLY STARTING TO PICK UP. WILL
KEEP THE SMALL CRAFT ADVISORY GOING AND END IT AT 7PM TONIGHT AS
PLANNED. THE HIGH SLOWLY SHIFTS OFF THE NE ATLANTIC COAST WHILE THE
LOW REACHES HUDSON BAY TOMORROW. GUIDANCE IS STILL SUGGESTING WINDS
WILL PICK UP TO 30KT THIS EVENING OVER THE NORTH HALF TO THE LAKE.
IN ADDITION...SOUNDINGS STILL INDICATE THAT GALE FORCE GUSTS LIE
JUST 200 FT ABOVE THE SURFACE. WILL KEEP OCNL GALE FORCE GUSTS GOING
THROUGH 03Z AND HIGHER VESSELS WILL PROBABLY ENCOUNTER MORE THAN
JUST OCNL GALE FORCE GUSTS.
THE LOWS COLD FRONT SWEEPS OVER THE LAKE LATE THIS EVENING WITH NW
WINDS 15-20 KT BEHIND IT. A WEAK SURFACE RIDGE MOVES OVER THE LAKE
TOMORROW AND WINDS QUICKLY DIMINISH. THE HIGH PUSHES EAST WITH
SOUTH WINDS EXPECTED ACROSS THE LAKE MONDAY AND TUESDAY. ANOTHER
LOW PASSES OVER THE SOUTHERN CANADIAN PRAIRIES EARLY NEXT WEEK...AND
EXPECTING THE PRESSURE GRADIENT TO TIGHTEN OVER THE NORTHERN HALF OF
THE LAKE. THEREFORE...HAVE 30KT WINDS OVER THE NORTHERN HALF OF THE
LAKE MONDAY NIGHT AND TUESDAY. WINDS TURN WEST AS THE LOW PUSHES
EAST AND ANOTHER WEAK SURFACE RIDGE SETS UP OVER THE LAKE.
LATE NEXT WEEK STILL LOOKS INTERESTING WITH A LARGE LOW CROSSING THE
PLAINS AND PASSING OVER LAKE SUPERIOR. MODEL TIMING IS NOT
CONSISTENT BETWEEN THE MODELS AND MODEL RUNS. THAT BEING SAID
GUIDANCE IS STILL SUGGESTING STRONG SOUTH WINDS LATE NEXT WEEK AHEAD
OF THE LOW.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 PM SATURDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 PM EDT SAT SEP 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 412 PM EDT SAT SEEP 28 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT SHORTWAVE TROUGH
FROM ERN NORTH DAKOTA INTO SW MN. AN AREA OF RAIN ALONG AND BEHIND
THE SFC COLD FRONT FROM NE MN THROUGH WRN WI WAS ADVANCING STEADILY
TOWARD UPPER MI. THE COLD FRONT WAS DEFINED BY A VERY NARROW HEAVIER
N-S RAIN BAND TO NEAR HYR AT 1930Z.
TONIGHT...FCST ONSET OF PCPN WAS DELAYED SLIGHTLY COMPARED TO THE
PREVIOUS FCSTS...PER RADAR TRENDS AND SHORT TERM MODELS. OTHERWISE...
THE COMBINATION OF MODERATE TO STRONG 700-300 MB QVECTOR
CONV...AROUND 100M 5H HEIGHT FALLS WITH TROUGH...STRONG 850-700MB
FGEN AND RIGHT ENTRANCE REGION FORCING FROM A 120 KNOT 250-300 MB
JET...AND GOOD MOISTURE AVAILABILITY WITH PWAT VALUES AT OR ABOVE 1.6
INCHES WILL SUSTAIN THE RAIN BAND AS IT MOVES THROUGH THE CWA
TONIGHT. THE SPEED OF THE FRONT MAY LIMIT OVERALL QPF AMOUNTS TO
0.20-0.35 INCH WITH LESSER AMOUNTS IN LOW LEVEL SRLY DOWNSLOPE FLOW
LOCATIONS NEAR LAKE SUPERIOR. THE FRONT AND POST-FRONTAL PCPN WILL
EXIT THE ERN CWA SHORTLY AFTER 06Z SUN WITH GOOD SUBSIDENCE/CLEARING
EXPECTED IN THE WAKE OF THE FRONT LATE TONIGHT.
SUNDAY...THE SHORTWAVE TROUGH WILL CONTINUE TO LIFT INTO NORTHERN
ONTARIO REACHING JAMES BAY BY SUN AFTERNOON. THOUGH SUBSIDENCE BEHIND
THE WAVE SHOULD CLEAR OUT MOST OF THE CLOUDS BY SUNRISE ON
SUNDAY...850-750 MB THERMAL TROUGH SUPPORT SCT-BKN STRATOCU CLOUDS
DEVELOPING OVR CNTRL AND EAST. MIXING TO 850 MB RESULTS IN MAX TEMPS
IN THE MID TO UPPERR 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 412 PM EDT SAT SEP 28 2013
STARTING 00Z MON...THE TROUGH/COLD FRONT THAT WILL MOVE THROUGH
TONIGHT WILL BE WELL E OF THE CWA...AS WILL ALL ASSOCIATED PRECIP.
MORE ZONAL UPPER LEVEL FLOW WILL BE PRESENT OVER THE REGION...WITH
UPPER TROUGHING OVER THE NW CONUS. THROUGH WED...ZONAL FLOW LOOKS TO
REMAIN THE DOMINANT UPPER PATTERN OVER THE CWA...WITH SEVERAL
DISTURBANCES MOVING ACROSS CANADA BUT STAYING FAR ENOUGH N OF THE
CWA TO RULE OUT SIGNIFICANT PRECIP.
WITH A WEAK SFC TROUGH/COLD FRONT BUILDING TO OUR W MON AND MON
NIGHT...THEN MOVING THROUGH THE CWA LATE TUE AND TUE NIGHT...WINDS
WILL INCREASE OUT OF THE SW AHEAD OF THE TROUGH...THEN TURN W TO WNW
LAT TUE THROUGH WED BEHIND THE TROUGH. THIS LEADS TO 850MB TEMPS
INCREASING TO AROUND 15C BY 00Z TUE /AN INCREASE OF AROUND 9C FROM
SUN/...AND POSSIBLY WARMING A BIT MORE THROUGH MON NIGHT. WHILE
HIGHS ON SUN LOOK TO BE IN THE 60S...HIGHS ON MON ARE EXPECTED TO BE
IN THE 70S TO NEAR 80 IN SOME SPOTS OVER WRN UPPER MI. LOWS ON MON
NIGHT SHOULD THEN BE IN THE MID 40S IN THE COLDEST SPOTS OVER ERN
UPPER MI TO THE MID 50S NEAR LAKE SUPERIOR AND W. LOOKS LIKE ANY
PRECIP WITH FROPA ON TUE/TUE NIGHT WILL STAY N OF LAKE SUPERIOR WITH
THE BETTER UPPER LEVEL FORCING. TUE SHOULD SEE SIMILAR TEMPS TO
MON...OR POSSIBLY A COUPLE OF DEGREES WARMER GIVEN THE WARM LOW
TEMPS MON NIGHT.
COOLER AIR ARRIVES TUE NIGHT...BUT BREEZY WINDS BEHIND THE COLD FRONT
WILL HELP KEEP LOW TEMPS FROM FALLING TOO LOW. WITH 850MB TEMPS OF
7-8C ON WED...TEMPS WILL BE COOLER THAN TUE WITH HIGHS PRIMARILY IN
THE 60S TO AROUND 70.
THINGS BECOME MUCH MORE UNCLEAR THU THROUGH NEXT SAT AS MODELS
CONTINUE TO SHOW SOME SORT OF UPPER LEVEL ENERGY MOVING INTO THE
CENTRAL CONUS. WHILE MODELS DO AGREE THAT THE ENERGY WILL BE
STRONGER /AND EITHER A DEEP TROUGH OR A CLOSED LOW/...THEY HAVE POOR
RUN TO RUN CONTINUITY AND POOR MODEL TO MODEL AGREEMENT. THIS LENDS
VERY LITTLE CONFIDENCE IN DETAILS FOR THIS PORTION OF THE FORECAST.
FOR THIS REASON...WILL LOAD A GENERAL CONSENSUS OF MODEL
GUIDANCE...AND AM FINE WITH HIGHER END POPS AS ALL MODEL SCENARIOS
WOULD LEAD TO PRECIP AT ONE TIME OR ANOTHER. IT IS WORTH POINTING
OUT THAT ALL MODELS AT THIS TIME ARE WARM ENOUGH TO NOT WARRANT
TALKING ABOUT MIXED PRECIP...SO IT SEEMS THAT THERE WILL NOT BE ANY
WINTER QUITE YET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 149 PM EDT SAT SEP 28 2013
EXPECT GUSTY SRLY WINDS AT ALL TAF SITES THIS AFTERNOON AHEAD OF AN
APPROACHING COLD FRONT. A PERIOD OF GUSTY WEST WINDS AT KCMX WILL ALSO
PREVAIL IN THE WAKE OF THE FRONT. RAIN WILL MOVE INTO KIWD AROUND
20Z AND KCMX/KSAW AT 22Z/00Z. CIGS SHOULD LOWER BRIEFLY TO
MVFR...ESPECIALLY AT CMX...WITH THE ARRIVAL OF THE RAIN BUT EXPECT
IMPROVEMENT TO VFR AS DRIER AIR MOVES IN BEHIND THE FRONT AND
SCATTERS OUT CLOUD DECK.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT SAT SEP 28 2013
A FRONT WILL SLIDE EAST ACROSS LAKE SUPERIOR THIS EVENING AND
DURING THE EARLY OVERNIGHT HOURS...SHIFTING THE WINDS TO THE WEST.
THERE COULD BE A FEW HOUR PERIOD OF GALE FORCE GUSTS OVER THE
WESTERN LAKE THIS EVENING BEHIND THE FRONT. HIGH PRESSURE
WILL THEN BUILD IN FOR SUNDAY AND QUICKLY DECREASE THE WINDS ACROSS
THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW
PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A
BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR MONDAY NIGHT
WITH A FEW GUSTS REACHING 25 KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1223 PM CDT Sat Sep 28 2013
.UPDATE...
Issued at 949 AM CDT SAT SEP 28 2013
No major changes to forecast thinking as rain and storms move through
this morning. Any thunder is confined to the leading edge of this
activity which has already made it into the Sedalia and Kirksville
areas. These storms may become a bit stronger as they track toward
eastern MO later today where temps are rising into the mid/upper 70s,
but threat for any strong storms west of the US-63 corridor is very
low. Rainfall amounts so far have generally been around a quarter of
an inch or less, though some gauges on the west side of the KC metro
have picked up over a half inch so far. Followed closely the HRRR for
the back edge of this activity since this model has had a good handle
on this system so far. Looks like rapid clearing will make it to the
I-35 corridor by early afternoon and into far eastern portions of the
forecast area by late afternoon/early evening.
&&
.SHORT TERM...(Today through Monday Night)
Issued at 344 AM CDT SAT SEP 28 2013
Forecast is still on line for much of the area to get some rain on
Saturday. Radar trends across central Kansas and eastern Nebraska
show widespread showers and thunderstorms. They appear to be in
association with a rather potent neutrally tilted trough, which is
currently situated over the western Plains. While this mid level
trough is providing decent mid level forcing for ascent the surface
cold front also seems to be a contributing factor of where the more
widespread showery activity is located. Currently the surface cold
front is located on a line from KSUX through KAUH and KGBD. The first
echoes should be encroaching upon the forecast area in far NW
Missouri within the hour and precip will continue to spread eastward
through the rest of the morning and afternoon hours. Expect showers
to form in the KC Metro area perhaps around 12z, lasting through
around 18z before dissipating and moving off to the east. Areas of
central Missouri will likely see precipitation begin in the late
morning or early afternoon, lasting through the afternoon hours
before moving off to the east by later this evening. Currently not
expecting much in the way of a severe threat, however models do
indicate perhaps up to 500-1000 J/kg of MU Cape as the showers move
through, which may increase the coverage of thunderstorm activity. In
conjunction with the moderate instability NAM does hint at around
20-30 kts of 0-6 km wind shear, which may add to the updraft strength
of select storms. As a result, still expect a NIL severe weather day,
however coverage of thunderstorm activity may increase slightly, and
perhaps an isolated updraft or two could bring some small hail and/or
gusty winds. As mentioned above, expect showers and thunderstorms to
exit the area from west to east by this evening. Expected QPF for
this system will be on the low end, considering it`s convective
nature, but with it`s progressive nature expect only a quarter to
half inch of rain, with perhaps a few isolated locations receiving
higher amounts of around three quarters of an inch.
Northerly cool and dry air will then settle into the area for the
remainder of the weekend, as the surface high moves into Missouri.
At the moment expecting overnight lows on Saturday night into Sunday
morning to drop well into the 40s, especially along the northern
half of the forecast area, with perhaps some lower 50s further
south. Sunday will bring sunny conditions, with perhaps slightly
warmer temperatures in the middle 70s. Monday will be a near repeat
of Sunday with sunny skies and temperatures in the middle to upper
70s.
.LONG TERM...(Tuesday through Friday)
Issued at 344 AM CDT SAT SEP 28 2013
Above normal temperatures and dry conditions are expected for
Tuesday and most of Wednesday, as broad zonal flow gradually turns
west southwest and southerly low-level winds increase. A deep trough
building over the northeast Pacific will begin dropping southeast by
late Wednesday, orienting the flow more southwest-northeast and
allowing a few disturbances to lift northeast into the forecast area
from early Thursday morning through Friday. This shift in the
pattern will make showers and storms possible for much of the latter
half of the week, but will also hold temperatures down a bit with
cloud cover and precipitation around the area. Model agreement is
still poor for timing the main trough axis into the central CONUS,
but precipitation will be likely with that system as it pushes
through, sometime Friday or Saturday. Significantly more seasonable
temperatures are expected behind this system, especially if the low
cuts off as indicated by the 00z runs of the EC and GFS.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1223 PM CDT SAT SEP 28 2013
Rapid improvement is moving in from the west at this hour with the
back edge of rain already clearing the KC area. An hour or two of
IFR/MVFR cigs will persist after the rain clears out before
conditions quickly lift into VFR for the rest of the evening. Back
edge of rain should reach the IRK-COU corridor by 23Z or so. Winds
will quickly decrease toward 00Z, becoming light and variable by
sunrise. This may favor a few areas of mist or fog toward sunrise given
the wet ground.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Leighton
LONG TERM...Laflin
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1239 PM CDT SAT SEP 28 2013
.UPDATE...
ISSUED AT 955 AM CDT SAT SEP 28 2013
1450Z RADAR IMAGERY SHOWS WIDESPREAD RAINFALL CONTINUES ACROSS THE
REGION. THERE APPEARS TO BE A BRIEF BREAK IN ACTIVITY WITHIN THE
CENTRAL VALLEY...BUT WILL NOT GET TOO CUTE WITH THE FORECAST. THE
AREA OF RAINFALL EAST OF THE VALLEY LIKELY ASSOCIATED WITH MID-
LEVEL FRONTOGENESIS...WHICH WILL ADVECT NORTHEASTWARD AND OUT OF
THE REGION QUICKLY. THE AREA OF RAINFALL WEST OF THE VALLEY LIKELY
ASSOCIATED WITH THE MAIN UPPER WAVE...AS SEEN IN 500MB-300MB
Q-VECTOR CONVERGENCE FROM THE MODELS. WILL FOLLOW THIS FORCING
FROM THE 12Z NAM FOR ENDING OF THE CATEGORICAL POPS TODAY. THIS
DELAYS THE ENDING OF RAINFALL AN HOUR TO TWO FROM PREVIOUS
FORECAST. THE 12Z HRRR/RAP AGREE WITH THIS CHANGE. WITH
THAT...ALSO DELAYED CLEARING A FEW HOURS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
FCST GOING AS EXPECTED. SFC LOW AT 08Z VERY NEAR MARSHALL MN AND
THIS IS PROGGED BY LATEST HRRR MODEL TO LIFT TO NEAR BEMIDJI-PARK
RAPIDS AREA IN THE 12-14Z PERIOD THEN TOWARD INTERNATIONAL FALLS
BY 16Z. MAIN PRECIP DEF ZONE BAND OVER ERN SD INTO ERN ND MAINLY
HOLDING ALONG AND WEST OF A ROSEAU TO DETROIT LAKES TO WHEATON
LINE. EXPECT RAIN AREA TO SHIFT BACK EAST AS SFC LOW MOVES TOWARD
BEMIDJI BY 12-14Z.
GOING OFF LATEST HRRR/RAP AND NAM12 TWEAKED POPS TO SHOW MAIN
PRECIP ENDING IN THE SRN RRV 15-17Z...THEN 17-19Z IN THEN NRN
VALLEY AND THEN 22-23Z IN LAKE OF THE WOODS REGION. RAIN TOTALS
PER AWOS/ASOS AND OTHER STATIONS INDICATE A TENTH OR TWO AN
HOUR...WITH MOST AREAS LIKELY TO RECEIVE AROUND AN INCH TOTAL FROM
THIS SYSTEM IN THE MAIN RAIN BAND IN THE RED RIVER VALLEY.
SKIES EXPECTED TO RAPIDLY CLEAR FROM THE WEST AND SOUTHWEST THIS
AFTN WITH A GENERALLY CLEAR SKY TONIGHT. WINDS WILL GO LIGHT AND
WITH A CLEAR SKY DO EXPECT LOWS TO REACH THE UPR 30S TO LOWER
40S...WITH AN ISOLD 35-36 PSBL IN PLACES SUCH AS LANGDON OR IN THE
SHEYENNE RIVER VALLEY (I.E. COOPERSTOWN AREA).
WINDS TO TURN SOUTH SUNDAY ALONG WITH PLENTY OF SUN AND TEMPS WILL
RISE INTO THE LOWER TO MID 70S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 311 AM CDT SAT SEP 28 2013
SOUTH WIND STAYS UP A BIT SUN NIGHT KEEPING TEMPS MILDER THAN
TONIGHT. WINDS TURN A BIT MORE SOUTHWEST ON MONDAY AND WITH 850
MB TEMPS IN THE MID TEENS EXPECT HIGHS 75 TO 80 IN MOST AREAS. DID
INTRODUCE A LOW POP MON EVE IN NE ND AND MON OVERNIGHT IN FAR NW
MN WITH SFC TROUGH PASSAGE. MAIN LOW WELL TO OUR NORTH SO ANY
PRECIP VERY LIGHT.
TUESDAY WILL BE DRY...BUT COOLER AND BREEZY IN THE WAKE OF MONDAY
NIGHT/S COLD FRONTAL PASSAGE. AFTERNOON HIGHS WILL BE 10 DEGREES
LOWER THAN MONDAY WITH WESTERLY WIND FROM 15 TO 25 MPH. NEAR ZONAL
FLOW ALOFT WEDNESDAY SHOULD RESULT IN MOSTLY DRY CONDITIONS WITH
TEMPERATURES NEAR OR SLIGHTLY COOLER THAN TUESDAY. 00 UTC GFS/ECMWF
BEGIN TO DIVERGE WEDNESDAY NIGHT THROUGH FRIDAY WITH THE TIMING AND
TRACK OF THE NEXT PACIFIC WAVE. THE GFS IS QUICKER AND FARTHER SOUTH
WHEREAS THE ECMWF IS SLOWER AND FARTHER NORTH WITH MUCH HIGHER
PRECIPITATION CHANCES ACROSS THE FORECAST AREA. MODEL RUN-TO-RUN
CONTINUITY HAS BEEN POOR...SO CONFIDENCE IS LOW AND WILL FOLLOW ALL
BLEND CHANCE POPS. DEPENDING ON THE SPEED OF THE SYSTEM...FRIDAY
COULD BE DRY OR SEE LINGERING SHOWERS DISSIPATING FROM WEST TO EAST
THROUGH THE DAY. NO MATTER THE MODEL SOLUTION...EXPECT DRY
CONDITIONS BY FRIDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE
NORTHERN PLAINS. WITH CLOUD COVER AND POTENTIAL RAIN...THURSDAY WILL
BE COOLER WITH HIGHS FROM THE MID 50S TO LOW 60S. FRIDAY WILL BE
EVEN COLDER IN THE WAKE OF THE PACIFIC WAVE/S COLD FRONT DROPPING
AFTERNOON HIGHS INTO THE 50S REGION-WIDE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1239 PM CDT SAT SEP 28 2013
VFR CONDITIONS SPREADING NORTH AND EAST HAVE CLEARED THE KDVL AREA
AND ARE APPROACHING KFAR. TRANSITION FROM LCL IFR / MVFR TO VFR WILL
OCCUR RELATIVELY QUICKLY AFTER -RA ENDS....REACHING KBJI CLOSER TO
00Z. WITH DECREASING CLDS EXPECT WESTERLY FLOW TO BRIEFLY GUST TO
AROUND 20KTS...BEFORE DYING OFF NEAR 00Z. VFR AFTER 00Z AND
SOUTHWEST FLOW LT 10KTS AFTER DARK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...EWENS
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1240 PM CDT SAT SEP 28 2013
.DISCUSSION...
/See below for aviation discussion/
&&
.AVIATION...
Band of showers and thunderstorms associated with a cold front from
Sonora to San Angelo to Abilene will spread east to Brady and
Junction this afternoon. IFR to MVFR CIGS and visibilities will
accompany the storms. Rain should move east of San Angelo around 3
PM and east of Abilene by 7 PM...as drier air begins to move in from
the northwest. Sonora...Brady...and Junction will see occasional
showers and thunderstorms into Sunday.
04
&&
.PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Sep 28 2013/
.UPDATE...
UPDATED FOR HIGHS TODAY.
&&
.DISCUSSION...
BAND OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE SLOWLY EAST
ACROSS WEST CENTRAL TEXAS. 11 AM TEMPERATURES ARE UP TO 10 DEGREES
BELOW FORECAST...AS CONVECTIVELY DRIVEN COLD FRONT FROM OZONA TO
SAN ANGELO TO COLEMAN CONTINUES TO MOVE SOUTHEASTWARD. REDUCED
HIGHS TODAY 5 TO 8 DEGREES ACCORDINGLY. MAIN THREAT CONTINUES TO
BE URBAN FLOODING DUE TO LOCALLY HEAVY RAINFALL.
04
&&
.PREV DISCUSSION... /ISSUED 645 AM CDT SAT SEP 28 2013/
DISCUSSION...
Please see aviation below for discussion.
AVIATION...
Look for very challenging flight weather conditions across West
Central Texas during the next 24 hours. Ceilings in the MVFR range
and Thunderstorms will be the primary concerns today. Overnight
tonight, the primary concern will be ceilings. I believe MVFR
ceilings will end across the Big Country and Concho Valley by 06Z.
However, I expect MVFR ceilings to linger elsewhere overnight.
Huber
PREV DISCUSSION... /ISSUED 337 AM CDT SAT SEP 28 2013/
SHORT TERM...
Today and Tonight
I`m expecting showers and thunderstorms to bring rain to West
central Texas during the next 24 hours. Everything has come
together; we have low-level moisture, instability, and lift. If most
of West Central Texas doesn`t receive good rainfall today and
tonight, we`re going to miss a really great opportunity.
Precipitable water values from the GFS increase to around 2 inches
by this afternoon. So, some thunderstorms may produce locally heavy
rainfall. The main thunderstorm threats will be heavy rainfall and
deadly lightning. Some areas may receive one half to one inch of
rain today, while a few locations may have up to two inches today.
I`m expecting convection to be along and ahead of the cold front.
I`m expect the front to move into our northwest Big Country counties
by mid morning; this timing fits well with the latest RUC and the
06Z NAM. I`m thinking the best rain chances today will be across the
central and eastern Big Country and most of the Heartland; that`s
where the deeper moisture will be. As the front shifts slowly
southeast, I expect the better rain chances to shift to mainly our
Northwest Hill Country counties overnight tonight. As for
temperatures, numbers close to guidance look good.
Huber
LONG TERM...
Sunday through Saturday...
A steady warm up can be expected next week, with a possible strong
cold front by next weekend. The cold front that will move through
West Central Texas today, will be south of the area Sunday morning.
The majority of the convection will be south of the area, but
lingering showers and thunderstorms will be possible across mainly
the southern and eastern counties. I have included slight chance to
chance PoPs, with most of the convection ending by 18z. Highs on
Sunday will generally be in the upper 70s to lower 80s, while
overnight lows drop into the lower to mid 60s.
A steady warm up is forecast through much of the week. Above normal
temperatures are forecast with highs in the upper 80s to lower 90s,
while overnight lows drop into the 60s. Our next weather player will
be a potent upper level trough that is forecast to be near the Four
Corners region by late Thursday, then swing across the Southern
Plains Saturday. This will drive a fairly strong cold front through
the area on Saturday. For now, I have trended temperatures down and
introduced slight chance PoPs across parts of the area. These may
need to be increased in the near future if the current model trends
continue. Below normal temperatures can be expected for the
remainder of next weekend and into the early part of following week.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 80 62 87 / 90 60 20 5 5
San Angelo 78 61 81 62 89 / 80 60 20 10 5
Junction 85 66 80 63 86 / 80 80 50 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/99
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1112 AM CDT Sat Sep 28 2013
.UPDATE...
UPDATED FOR HIGHS TODAY.
&&
.DISCUSSION...
BAND OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE SLOWLY EAST
ACROSS WEST CENTRAL TEXAS. 11 AM TEMPERATURES ARE UP TO 10 DEGREES
BELOW FORECAST...AS CONVECTIVELY DRIVEN COLD FRONT FROM OZONA TO
SAN ANGELO TO COLEMAN CONTINUES TO MOVE SOUTHEASTWARD. REDUCED
HIGHS TODAY 5 TO 8 DEGREES ACCORDINGLY. MAIN THREAT CONTINUES TO
BE URBAN FLOODING DUE TO LOCALLY HEAVY RAINFALL.
04
&&
.PREV DISCUSSION... /ISSUED 645 AM CDT SAT SEP 28 2013/
DISCUSSION...
Please see aviation below for discussion.
AVIATION...
Look for very challenging flight weather conditions across West
Central Texas during the next 24 hours. Ceilings in the MVFR range
and Thunderstorms will be the primary concerns today. Overnight
tonight, the primary concern will be ceilings. I believe MVFR
ceilings will end across the Big Country and Concho Valley by 06Z.
However, I expect MVFR ceilings to linger elsewhere overnight.
Huber
PREV DISCUSSION... /ISSUED 337 AM CDT SAT SEP 28 2013/
SHORT TERM...
Today and Tonight
I`m expecting showers and thunderstorms to bring rain to West
central Texas during the next 24 hours. Everything has come
together; we have low-level moisture, instability, and lift. If most
of West Central Texas doesn`t receive good rainfall today and
tonight, we`re going to miss a really great opportunity.
Precipitable water values from the GFS increase to around 2 inches
by this afternoon. So, some thunderstorms may produce locally heavy
rainfall. The main thunderstorm threats will be heavy rainfall and
deadly lightning. Some areas may receive one half to one inch of
rain today, while a few locations may have up to two inches today.
I`m expecting convection to be along and ahead of the cold front.
I`m expect the front to move into our northwest Big Country counties
by mid morning; this timing fits well with the latest RUC and the
06Z NAM. I`m thinking the best rain chances today will be across the
central and eastern Big Country and most of the Heartland; that`s
where the deeper moisture will be. As the front shifts slowly
southeast, I expect the better rain chances to shift to mainly our
Northwest Hill Country counties overnight tonight. As for
temperatures, numbers close to guidance look good.
Huber
LONG TERM...
Sunday through Saturday...
A steady warm up can be expected next week, with a possible strong
cold front by next weekend. The cold front that will move through
West Central Texas today, will be south of the area Sunday morning.
The majority of the convection will be south of the area, but
lingering showers and thunderstorms will be possible across mainly
the southern and eastern counties. I have included slight chance to
chance PoPs, with most of the convection ending by 18z. Highs on
Sunday will generally be in the upper 70s to lower 80s, while
overnight lows drop into the lower to mid 60s.
A steady warm up is forecast through much of the week. Above normal
temperatures are forecast with highs in the upper 80s to lower 90s,
while overnight lows drop into the 60s. Our next weather player will
be a potent upper level trough that is forecast to be near the Four
Corners region by late Thursday, then swing across the Southern
Plains Saturday. This will drive a fairly strong cold front through
the area on Saturday. For now, I have trended temperatures down and
introduced slight chance PoPs across parts of the area. These may
need to be increased in the near future if the current model trends
continue. Below normal temperatures can be expected for the
remainder of next weekend and into the early part of following week.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 80 62 87 / 90 60 20 5 5
San Angelo 78 61 81 62 89 / 80 60 20 10 5
Junction 85 66 80 63 86 / 80 80 50 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/99
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
313 PM CDT SAT SEP 28 2013
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM
WATER VAPOR/RUC COMBO SHOWS UPPER TROUGH WITH DECENT 200-300
MILLIBAR SPEED MAX ON THE EASTERN SIDE. BRUNT OF MAIN VORT LIFTING
NORTHEAST FROM NRN MN. TIGHT PRESSURE GRADIENT WITH GUSTY
SOUTH/SOUTHEAST WINDS WILL GRADUALLY GIVE WAY TO WEST/NORTHWEST
WINDS AFTER FROPA. SURFACE LOW LIFTING INTO CANADA FROM MN. BAND
OF SHOWERS TO PUSH THROUGH SRN WI THROUGH THE EVENING HOURS. THIS
WILL BE HELPED ALONG BY THE COMBO OF LOW LEVEL FORCING AND THE
STRONG JET ACTION ON THE EASTERN SIDE OF UPPER TROUGH. DECENT
MOISTURE SURGE WITH LOW TO MID 60S DP/S INTO SE IA. HRRR HAS BEEN
LINGERING PRECIP IN THE FAR SE A BIT LONGER WITH EACH RUN. WILL
HANG ONTO SOME SMALL CHANCES IN THE SE AFTER MIDNIGHT FOR A TIME.
SUNDAY...FORECAST CONFIDENCE HIGH
SURFACE HIGH AND DRY AIRMASS TAKES HOLD. LINGERING 850 COOL POOL
GETS DISPLACED AS WEAK WARM AIR ADVECTION COMMENCES IN THE
AFTERNOON. 925 TEMPS OF 14-16C SET UP FOR HIGHS MOSTLY IN THE
UPPER 60S TO LOW 70S.
SUNDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE HIGH
A 100 KT WSWLY POLAR JET STREAM WILL STRETCH FROM THE PACIFIC NW
TO ONTARIO CANADA THROUGH THIS PERIOD WITH LOW AMPLITUDE RIDGING
OVER THE ERN USA. AT THE SFC...A HIGH PRESSURE RIDGE WILL EXTEND
FROM MI TO MO SUN NT THEN MOVE TO THE ERN GREAT LAKES AND THE OHIO
RIVER VALLEY FOR MON AND TUE. ALSO...A STRONG AND OCCLUDED LOW WILL MOVE
EAST ACROSS SRN CANADA DURING THIS TIME.
SLY FLOW AND LOW TO MID LEVEL WARM ADVECTION WILL DEVELOP DURING
THIS PERIOD...BEING WEAK FOR SUN NT...BUT INCREASING MON AND TUE.
A THERMAL RIDGE WILL THEN MOVE ACROSS THE REGION ON TUE AHEAD OF
THE WEAKENING TAIL END OF THE COLD FRONT EXTENDING OUT OF CANADA.
WARM AND DRY CONDITIONS ARE EXPECTED. 925 MB TEMPS IN THE UPPER
TEENS TO LOWER 20S CELSIUS SUPPORT HIGH TEMPS IN THE MID 70S MON
AND LOWER 80S FOR TUE. SUN NT WILL BE COOL DUE TO THE CLOSE
PROXIMITY OF THE HIGH AND DECOUPLED WINDS...BUT WITH MILD NIGHTS
THEREAFTER VIA SLY FLOW AND WAA.
.LONG TERM...
WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE LOW TO MEDIUM
THE EXTENDED MODELS DEPICT AN UPPER TROUGH DIGGING INTO THE PACIFIC
NW ON WED...BUT THEN DIFFER ON THE TIMING AND EVOLUTION OF THE
UPPER TROUGH AND EVENTUAL LEE SIDE TROUGH AND CYCLOGENESIS AS IT
MOVES IN THE CENTRAL USA AND GREAT LAKES. THE BEST ESTIMATE AT
THIS TIME IS FOR A SFC TROUGH TO EXTEND FROM THE CENTRAL PLAINS
INTO MN ON THU FOLLOWED BY CYCLOGENESIS NEWD INTO ONTARIO FOR THU
NT INTO SAT. WED WILL BE DRY WITH A SFC RIDGE OVER THE AREA BUT WARM
ADVECTION PCPN WILL BE POSSIBLE WED NT INTO THU NT FOLLOWED BY
FROPA PCPN ANYTIME FROM FRI INTO SAT. ABOVE NORMAL TEMPS WILL
CONTINUE UNTIL COLD FROPA.
&&
.AVIATION/00Z TAFS/...VFR CONDITIONS CONTINUE THIS AFTERNOON WITH
GUSTY SSE WINDS AHEAD OF APPROACHING FRONTAL BOUNDARY. WATER VAPOR
SHOWS THE UPPER TROUGH QUITE WELL WITH STRONG JET MAX ON EASTERN
SIDE. RAIN PUSHING INTO WRN WI AND CONTINUE TO SPREAD ACROSS THE
AREA INTO EARLY THIS EVENING. CURRENT TIMING IN TAFS LOOK PRETTY
GOOD SO NOT EXPECTING ANY SIGGY CHANGES THERE...21Z IN KMSN AND
CLOSE TO 00Z AT KMKE. JUST A FEW HOURS OF PRECIP POTENTIAL AT ANY
GIVEN LOCATION. HIGH PRESSURE DOMINATES SUNDAY. MOS AND LLVL RH
PROGS SHOW A GOOD DEAL OF SUNSHINE.
&&
.MARINE...THE TIGHT SURFACE PRESSURE GRADIENT AHEAD OF A COLD FRONT
HAS BROUGHT GUSTS AT OR ABOVE CRITERIA. THE SOUTHEAST WINDS WILL
SHIFT SOUTH WITH FREQUENT GUSTS UP TO 25 KNOTS. THE GUSTY WINDS WILL
GENERATE HIGH WAVES...ESPECIALLY NORTH OF PORT WASHINGTON. WINDS
WILL EASE EARLY THIS EVENING AS GRADIENT WEAKENS AHEAD OF
FRONT...BUT 06Z END TIME LOOKS ON TRACK TO ALLOW WAVES TO SUBSIDE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ644>646.
SMALL CRAFT ADVISORY UNTIL 1 AM CDT SUNDAY FOR LMZ643.
&&
$$
TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR
SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
116 PM CDT SAT SEP 28 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CDT SAT SEP 28 2013
MAIN FOCUS THROUGH THE SHORT TERM WILL BE COLD FRONTAL PASSAGE AND
ASSOCIATED RAINFALL.
SURFACE MAP EARLY THIS MORNING HAS A COLD FRONT EXTENDING FROM
WESTERN ONTARIO CANADA/WESTERN MN...THROUGH EASTERN NEBRASKA AND
CENTRAL KS. RADAR MOSAIC SHOWING A RESPECTABLE 100 MILE WIDE BAND OF
FAIRLY SOLID SHOWERS AND AN OCCASIONAL EMBEDDED THUNDERSTORM BEHIND
THE FRONT IN STRONG 850-700MB FRONTOGENESIS/MODERATE MOISTURE
TRANSPORT. THIS ENERGY WAS BEING STEERED BY A VIGOROUS/DEEP
MID-LEVEL TROUGH MOVING EAST ACROSS EASTERN MT/WY/CO PER WATER VAPOR
SATELLITE/RAP 500MB ANALYSIS. ALSO NOTED ON WATER VAPOR IMAGERY WAS
A NARROW CORRIDOR OF SUBTROPICAL TAP STREAMING NORTHWARD AHEAD OF
THIS WAVE. RAP PRECIPITABLE WATER VALUES WHERE THE SHOWERS/EMBEDDED
THUNDERSTORMS WERE FALLING ARE IN THE 1.5-2" RANGE OR 200-250
PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. OTHERWISE...SKIES ACROSS
THE FORECAST AREA RANGED FROM CLEAR TO PARTLY CLOUDY WITH MILD
TEMPERATURES IN THE MIDDLE AND UPPER 50S...TO THE MIDDLE 60S.
LOOK FOR THE COLD FRONT TO MAKE EASTWARD PROGRESSION ACROSS THE AREA
TODAY. ALTHOUGH MOISTURE TRANSPORT DIMINISHES SOME THROUGH THE
DAY...700-300 PV-ADVECTION/850-700MB FRONTOGENESIS REMAINS FAIRLY
STRONG. BASED ON THIS SIGNAL AND WRF MODEL OUTPUT...APPEARS THE AREA
WILL SEE SOME RAINFALL. RAINFALL AMOUNTS ARE EXPECTED TO BE IN THE
1/4 TO 1/2 INCH RANGE. SOME ELEVATED INSTABILITY WILL ALSO EXIST
GENERALLY ABOVE 700MB FOR POCKETS OF THUNDER WITHIN THIS BAND OF
SHOWERS. LOOK FOR TEMPERATURES TO TOP OFF IN THE UPPER 60S TO THE
MIDDLE 70S...THEN SLOWLY FALL THROUGH THIS AFTERNOON WITH THE
FRONTAL PASSAGE AND IN THE SHOWER ACTIVITY.
PLAN ON THE FRONT AND RAIN TO PUSH EAST OF THE AREA THIS EVENING
WITH HIGH PRESSURE BUILDING OVERHEAD OVERNIGHT. CLEARING SKIES AND
RELATIVELY MOIST LOWER BOUNDARY LAYER ARE EXPECTED TO PRODUCE PATCHY
FOG LATE TONIGHT...MAINLY IN THE RIVER VALLEYS WHERE WINDS WILL BE
MORE LIKELY TO DECOUPLE. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE
40S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CDT SAT SEP 28 2013
GFS AND ECMWF ARE IN EXCELLENT AGREEMENT IN KEEPING THE MAIN STORM
TRACK NORTH OVER CENTRAL CANADA FOR SUNDAY THROUGH WEDNESDAY. THIS
KEEPS US DRY WITH BREEZY SOUTH-SOUTHWEST SURFACE FLOW //AT LEAST
INTO TUESDAY//WHICH WILL HELP DRAW UNSEASONABLY WARM AIR INTO THE
REGION. LOOK FOR HIGHS SUNDAY IN THE UPPER 60S TO THE MIDDLE
70S...WARMING INTO THE 70S TO AROUND THE 80 DEGREE MARK TUESDAY AND
WEDNESDAY.
LOW PRESSURE THEN MOVES OUT OF THE INTER-MOUNTAIN WEST AND INTO THE
PLAINS WEDNESDAY NIGHT AND THURSDAY WITH INCREASING MOISTURE
TRANSPORT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. RESULT
WILL BE INCREASING CLOUDS WITH A GOOD CHANCE FOR SHOWERS AND
THUNDERSTORMS.
MODELS THEN DIVERGE A BIT FOR THURSDAY NIGHT INTO FRIDAY WITH
HANDLING OF THE MAIN SURFACE LOW MOVING OUT OF THE PLAINS. THE ECMWF
TAKES THE LOW TO NEAR THE ARROWHEAD OF MN BY FRIDAY EVENING WHICH
WOULD KEEP US WARMER WITH ISOLATED SHOWERS AND THUNDERSTORMS OR
POSSIBLY COMPLETELY DRY WITH A CAP IN PLACE. THE GFS ON THE OTHER
HAND FAVORS A FARTHER SOUTH SOLUTION WITH THE LOW WHICH WOULD KEEP
US IN MORE OF A DEFORMATION RAIN SHIELD AND COOLER. FOR NOW...WILL
FOLLOW A MODEL CONSENSUS WITH RESULTING HIGH TEMPERATURES IN THE 60S
AND SMALLER-END RAIN PROBABILITIES.
&&
.AVIATION...THROUGH 18Z SUNDAY
115 PM CDT SAT SEP 28 2013
STRONG COLD FRONT ADVANCING EAST ACROSS MN/IA...WITH AN EXTENSIVE
AREA OF SHOWERS ALONG AND AHEAD OF IT. ALREADY RAINING AT KRST AT
ISSUANCE...AND WILL BE AT KLSE SHORTLY. NO LIGHTNING SHOWING
UP...EITHER GROUND STROKES OR ALOFT...ALTHOUGH AS WE REACH PEAK
HEATING CANNOT RULE IT OUT EAST AND SOUTH OF KLSE. LEFT OUT OF THE
TAFS...BUT COULD IMPACT THOSE FLYING EAST/SOUTH FROM EITHER
AIRFIELD. GUSTY WINDS ASSOCIATED WITH THIS SYSTEM AS IT PASSES.
WIND FROM THE SOUTH WITH G30 KTS AT TIMES AHEAD OF THE FRONT AND
RAIN SHIELD...WITH WINDS FROM THE WEST IN THE 30-40 KT RANGE
BEHIND IT. FOCUS FOR STRONGEST WINDS SHIFTING NORTH WITH THE MAIN
SHORT WAVE...SO DO NOT ANTICIPATE WE WILL SEE THAT KIND OF SPEED
FOR EITHER AIRFIELD. BUT FLIGHTS HEADING NORTH/WEST WILL NEED TO
BE AWARE OF THAT. EXPECT CLEARING SKIES THIS EVENING AS DRY AIR
SURGES IN BEHIND THE FRONT. WINDS WILL DIMINISH AS WELL. LAST
CONCERN WILL BE FOR THE SMALL POTENTIAL FOR VALLEY FOG AT KLSE
TONIGHT. WINDS DO DIE OFF AND THERE WILL BE RESIDUAL MOISTURE
AVAILABLE DUE TO THE RAIN. BUT FEEL THERE WILL BE JUST A LITTLE
TOO MUCH MIXING OF THE DRY AIR ALOFT TO ALLOW FOR REDUCED
VISIBILITY AND A STRATUS/FOG DECK IN THE VALLEY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...MW