Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/21/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
621 PM MDT FRI SEP 20 2013
.UPDATE...
ISSUED AT 616 PM MDT FRI SEP 20 2013
RAN A QUICK UPDATE TO REDUCE CLOUD COVER ACROSS THE STATE.
SCATTERED CLOUDS SHOULD HANG ON ALONG THE NEW MEXICO BORDER
THROUGH 10 PM...WITH CLEAR SKIES ELSEWHERE. ALSO ADDED THE MENTION
OF PATCHY FOG OVER THE SAN LUIS VALLEY LATE TONIGHT INTO SATURDAY
MORNING...BASED ON THE LATEST MODEL DATA AND BUFKIT SOUNDINGS. MOZLEY
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 331 PM MDT FRI SEP 20 2013
QUIET WEATHER OVER THE AREA TODAY BENEATH TRANSIENT UPPER RIDGE.
STRATUS HAS CLEARED OUT OF MOST OF THE SE PLAINS...THOUGH COOLER AIR
MASS OVER THE REGION HAS KEPT SE PLAINS CAPPED. STILL WAITING TO
SEE IF SUFFICIENT HEATING WILL OCCUR TO POP A THUNDERSTORM OR TWO
ALONG THE CREST OF THE SOUTHERN SANGRES...AND PERHAPS ACROSS THE
EASTERN SAN JUAN MOUNTAINS...BUT SO FAR CONVECTION HAS HAD A HARD
TIME GETTING GOING...WITH AIRMASS LOOKING TOO DRY ACROSS THE SW MTS
WHERE DEW POINTS HAVE DROPPED INTO THE 20S...AND TOO CAPPED AND COOL
FOR THE SOUTHERN SANGRES. EACH SUCCESSIVE HRRR RUN HAS BACKED OFF
WITH QPF FOR THOSE AREAS...SO HAVE TRIMMED BACK POPS INTO THE SILENT
CATEGORY.
SOUTHWEST FLOW INCREASES OVER THE AREA FOR SUNDAY. NAM12 PICKS UP
SOME LOW LEVEL MOISTURE AND GENERATES SOME OROGRAPHIC SHOWERS ACROSS
THE SOUTHWEST MTS EARLY SATURDAY MORNING. THIS COULD BE A BIT
OVERDONE...BUT GFS HINTS AT THIS TOO SO WILL MAINTAIN SOME ISOLATED
SHOWERS FOR THAT AREA. BY AFTERNOON...MODELS SHOW SOME ISOLATED
THUNDERSTORMS SPREADING NORTH AND EASTWARD INTO THE SAWATCH AND
MOSQUITO RANGES AND THE SANGRES. OTHERWISE...TEMPERATURES SHOULD
REBOUND NICELY BACK INTO THE 80S FOR THE SE PLAINS WITH A MIX OF 60S
AND 70S FOR THE MOUNTAIN AREAS. SOUTHERLY WINDS WILL INCREASE
ACROSS THE AREA AS THE LEE TROF DEEPENS AHEAD OF THE NEXT
APPROACHING TROF. STRONGEST WINDS WILL BE ACROSS THE HIGHER PEAKS
IN THE AFTERNOON AND ALONG THE FAR EASTERN BORDER ON THE EAST SIDE
OF THE SFC TROF AXIS. BOTH AREAS COULD SEE GUSTS IN THE 25-30 KT
RANGE. -KT
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 331 PM MDT FRI SEP 20 2013
.SATURDAY NIGHT THROUGH SUNDAY NIGHT...TROUGH MOVES ACROSS THE
REGION SUNDAY AFTERNOON AND EVENING. MODELS HAVE SOME DIFFERENCES
ON THE STRENGTH OF THE TROUGH. THE NAM IS THE WEAKEST WHILE THE EC
IS THE STRONGEST. MAIN CONCERNS WITH TROUGH PASSAGE WOULD BE SNOW
LEVELS ALONG THE CONTINENTAL DIVIDE AND WINDS OVER THE EASTERN
MOUNTAINS AND PLAINS. MOST OF THE PRECIPITATION OVER THE
CONTINENTAL DIVIDE REGION OCCURS AHEAD OF THE COLDEST AIR
ALOFT...AND SNOW IS MOSTLY LIMITED TO THE HIGHEST PEAKS. SNOW
LEVELS COULD FALL BELOW TREE LINE BEFORE PRECIPITATION ENDS FOR
SOME ACCUMULATIONS. IF THE TROUGH IS DEEPER...MORE SNOW COULD FALL
BELOW TREE LINE. THE BEST CHANCES FOR SNOW BELOW TREELINE WILL BE
SUNDAY EVENING. SECOND CONCERN WILL BE WINDS. GUSTY SOUTH TO
SOUTHWEST WINDS WILL DEVELOP AHEAD OF THE TROUGH SUNDAY ON THE
PLAINS. GFS AND EC HAVE THE 500MB TROUGH CUT OFF BRIEFLY AS IT
LIFTS NORTHEAST INTO NEBRASKA. HAVE SOME CONCERNS FOR A BRIEF
PERIOD OF STRONG WINDS SUNDAY EVENING OVER THE EASTERN MOUNTAINS
AND INTERSTATE 25 CORRIDOR. MODELS DO NOT HAVE STRONG WINDS AT
THIS TIME...BUT HAVE SEEN WINDY CONDITIONS WITH SIMILAR PATTERNS.
.MONDAY THROUGH WEDNESDAY...DRY AND WARM PATTERN DEVELOPS BEHIND
DEPARTING TROUGH AND AHEAD OF THE NEXT TROUGH. BREEZY TO WINDY
CONDITIONS ARE POSSIBLE ON WEDNESDAY AS SOUTHWEST FLOW ALOFT
STRENGTHENS AHEAD OF THE NEXT TROUGH MOVING INTO THE PACIFIC
NORTHWEST.
.THRUSDAY AND FRIDAY...EC AND GFS HAVE THE TROUGH OVER THE
NORTHWEST US MOVING NORTHEASTWARD ACROSS THE NORTHERN ROCKIES.
REGION WILL BE ON THE SOUTHERN END OF THE TROUGH. BOTH MODELS
SUGGEST A COLD FRONT IN THE REGION...WITH THE POTENTIAL FOR SOME
UPSLOPE ON THE EASTERN PLAINS. TOO EARLY TO GET VERY SPECIFIC ON
DETAILS SUCH AS THE LOCATION OF THE FRONT...STRENGTH OF EASTERLY
UPSLOPE FLOW AND STRENGTH OF THE TROUGH. GRIDS HAVE A MODEST
COOLING TREND WITH SOME ISOLATED POPS. --PGW--
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 331 PM MDT FRI SEP 20 2013
VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE NIGHT
WITH PATCHY REMNANT CLOUD COVER AROUND KCOS DISSIPATING BY 00Z.
EXPECT CLEAR SKIES OVERNIGHT THOUGH KALS COULD SEE A RETURN OF SOME
PATCHY GROUND FOG TOWARDS 12Z. FOR NOW HAVE KEPT VIS IN THE MVFR
CATEGORY FOR A COUPLE HOURS AROUND SUNRISE...BUT VIS COULD VERY WELL
DROP INTO THE IFR RANGE IF SKIES REMAIN SUFFICIENT CLEAR.
OTHERWISE...VFR CONDITIONS WILL CONTINUE INTO SATURDAY WITH WINDS
INCREASING FROM THE SOUTH DURING THE AFTERNOON WITH SPEEDS 10-15
KTS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOZLEY
SHORT TERM...KT
LONG TERM...PGW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
320 PM MDT THU SEP 19 2013
.SHORT TERM...AREA OF ELONGATED MID LEVEL POTENTIAL VORTICITY
EXTENDING FROM FAR NORTHEAST COLORADO SOUTHWEST ACROSS THE PLAINS
INTO THE SOUTHERN FOOTHILLS AND PARK COUNTY HEADING EAST. THIS
FEATURE HELPED DEVELOP ISOLATED RAIN SHOWERS...WITH A FEW
THUNDERSTORMS OVER SOUTH PARK AND SOUTHERN FOOTHILLS. RAINFALL HAD
BEEN LIGHT...LESS THAN A TENTH OF AN INCH. THIS ACTIVITY WAS
SHIFTING EAST WITH THE POTENTIAL VORTICITY. LATEST SATELLITE
SHOWING A DECENT BACK EDGE OF THE MOISTURE WITH DRIER AIR MOVING
SOUTH. MODELS SHOW THIS FEATURE CONTINUING TO SHIFT EAST INTO THE
EVENING...WITH THE LATEST HRRR AND RAP SHOWING ALL THE
PRECIPITATION EAST OF THE AREA BY MIDNIGHT. THIS SEEMS REASONABLE
BASED ON THE CURRENT TRENDS. WILL KEEP A SLIGHT CHANCE OF STORMS
ACROSS PARK COUNTY AND SOUTHERN FOOTHILLS AND PALMER DIVIDE THIS
EVENING. THE NAM SEEMS A BIT SLOWER IN SHIFTING THE PRECIPITATION
EASTWARD...WILL LEAN TOWARD THE HRRR AND RAP SOLUTIONS. AFTER
MIDNIGHT...LOW LEVEL SOUTHEAST WINDS COULD BRING SOME LOW LEVEL
MOISTURE BACK INTO THE FOOTHILLS. THIS SHOWN BY FORECAST
SOUNDINGS. WILL INCREASE CLOUD COVER A BIT...ESPECIALLY ACROSS
LINCOLN COUNTY. OVERNIGHT TEMPERATURES TO COOL INTO THE 40S ACROSS
NORTHEAST COLORADO WITH MOUNTAIN VALLEYS NEAR OR BELOW FREEZING.
ON FRIDAY...UPPER RIDGE OVER GREAT BASIN SHIFTS EAST WITH THE AXIS
ALONG THE COLORADO WESTERN BORDER. NORTHWEST FLOW ALOFT WILL
CONTINUE TO SPREAD DRIER AND MORE SUBSIDENT AIR ACROSS THE THE
AREA. CLOUDS SHOULD DECREASE DURING THE MORNING WITH MAINLY SUNNY
CONDITIONS BY THE AFTERNOON. TEMPERATURES ACROSS THE PLAINS TO
WARM INTO THE LOWER AND MIDDLE 70S.
.LONG TERM...A PAIR OF WEATHER SYSTEMS WILL MOVE ACROSS THE
STATE...ONE ON SUNDAY AND ANOTHER LATE NEXT WEEK. IN THE
MEANTIME...DRY AND SEASONABLE TEMPERATURES WILL PREVAIL. THE GFS
AND ECMWF MODELS ARE IN GOOD AGREEMENT AS THESE WELL DEFINED
TROUGHS TRAVERSE ACROSS THE WESTERN UNITED STATES. SATURDAY WILL
BE WARM AND SUNNY WHILE SUNDAY WILL BE A TRANSITION AHEAD OF THE
APPROACHING SYSTEM. PRECIPITATION SHOULD SPREAD INTO THE MOUNTAINS
BY SUNDAY AFTERNOON AND THEN MOVE ACROSS THE PLAINS SUNDAY NIGHT.
TEMPERATURES COULD DROP COLD ENOUGH FOR A CHANCE OF SNOW ABOVE
11000 FEET AS THE SYSTEM MOVES THROUGH. BEYOND SUNDAY...A RETURN
TO WESTERLY FLOW ALOFT WILL BRING WARM TEMPERATURES AND DRY
WEATHER BACK TO THE FORECAST AREA. NEXT FRIDAY MAY BE THE NEXT
TIME THE FORECAST AREA SEES ANY PRECIPITATION. AT THIS TIME...THE
SYSTEM LOOKS A BIT STRONGER THAN THE FIRST SYSTEM OVER THIS
WEEKEND.
&&
.AVIATION...NORTHEAST TO EAST WINDS TO SHIFT TO THE SOUTHEAST BY
00Z AS SURFACE HIGH MOVE SOUTH ACROSS THE EASTERN PLAINS. MODELS
CONTINUE TO SHOW SOME LOW LEVEL MOISTURE SPREADING NORTH AFTER
06Z. CEILINGS OF 4000 TO 6000 FEET AGL STILL EXPECTED TO DEVELOP
BETWEEN 07Z AND 13Z. SOUTHEAST SURFACE WINDS TO CONTINUE THROUGH
THE DAY FRIDAY AS DRIER AIR SPREADS OVER THE AREA. SHOULD SEE
CEILINGS IMPROVE AFTER 13Z.
&&
.HYDROLOGY...LINGERING SHOWERS AND A FEW THUNDERSTORMS ACROSS
SOUTH PARK AND SOUTHERN FOOTHILLS WILL COME TO AN END AROUND
MIDNIGHT AS DRIER AIR MOVES INTO THE REGION. ANY RAINFALL AMOUNTS
WILL BE LIGHT. NO SHOWERS OR STORMS EXPECTED FRIDAY.
RIVER LEVELS HAVE FLATTENED AND WILL GRADUALLY RECEDE OVER THE
NEXT FEW DAYS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLOOD WARNING CONTINUES FOR THE SOUTH PLATTE RIVER FROM
KERSEY TO THE NEBRASKA STATE LINE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
338 PM MDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM MDT THU SEP 19 2013
FAIRLY MEAGER CONVECTION OUT THERE SO FAR WITH DEW POINTS
STRUGGLING TO REBOUND ALONG THE NORTHERN PORTIONS OF THE AREA
BEHIND THIS MORNING`S COLD FRONT. THEY ARE SLOWLY CREEPING UP INTO
THE LOWER 40S TO MID 40S ACROSS EL PASO AND PUEBLO COUNTIES AS
WINDS SWING AROUND FROM THE EAST THIS AFTERNOON. FARTHER
EAST...DEW POINTS AT KLHX AND KLAA ARE STILL HOVERING IN THE 50S.
THUS HIGHEST MIXED LAYER CAPES OFF OF SPC MESO ANALYSIS IS RUNNING
AROUND 1000 J/KG ACROSS THE SOUTHEAST PLAINS SOUTH OF HIGHWAY
50...BUT THERE APPEARS TO BE A LITTLE CIN TO OVERCOME YET OUT THAT
WAY. AS THE UPPER TROF TRAILS ACROSS THE AREA THIS EVENING...SHORT
RANGE HIGH RES MODELS (LOCAL 4KM WRF...HRRR AND NAM12) ALL SHOW A
WINDOW FOR SOME ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST MTS/SPREADING INTO THE ADJACENT PLAINS THROUGH THE
EVENING. WITH FORCING STILL COMING THROUGH ITS HARD TO ARGUE.
HOWEVER...HAVE NOTICED TREND IN HRRR TO DECREASE COVERAGE OF QPF
ACROSS THE SOUTHERN I-25 CORRIDOR WITH EACH RUN. AFTER MIDNIGHT
THINK MOST OF THE ACTIVITY WILL BE DONE...HOWEVER...LOW LEVEL
WINDS SWING AROUND FROM THE SOUTHEAST AND MODEL SOUNDINGS BECOME
DEEPLY SATURATED SUGGESTING POTENTIAL FOR LOTS OF LOW
CLOUDS...FOG...AND EVEN PATCHY DRIZZLE ALONG THE SOUTHERN SLOPES
OF THE PALMER DIVIDE WHERE UPSLOPE WILL BE MAXIMIZED. HAVE THROWN
IN SOME ISOLATED -SHRA AND DRIZZLE FOR THE LATE NIGHT/EARLY
MORNING HOURS ALONG WITH AREAS OF FOG ALONG THE I-25 CORRIDOR.
STRATUS WILL SLOWLY CLEAR ON FRIDAY...THOUGH THINK THAT SOUTHERN
SLOPES OF THE PALMER DIVIDE/COLORADO SPRINGS AREA MAY HANG ON TO
CLOUD COVER THROUGH THE MORNING BEFORE BREAKS START TO APPEAR IN THE
AFTERNOON...AS IS THE TYPICAL PATTERN FOR SOUTHERLY UPSLOPE CASES.
OTHERWISE...MODELS KEEP FORECAST AREA DRY FRIDAY AFTERNOON...WITH SE
PLAINS REMAINING CAPPED. TEMPERATURES SHOULD BE ABOUT A CATEGORY COOLER THAN
THOSE OF TODAY. -KT
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM MDT THU SEP 19 2013
GENERALLY WARM AND DRY WEATHER STILL ON TRACK FOR THE EXTENDED...WITH
JUST A COUPLE OF STORM SYSTEMS TO CONTEND WITH. THE WEEKEND STARTS
OUT WARM AND DRY. SHOULD SEE 80S OVER THE PLAINS BOTH SAT AND SUNDAY.
GFS MOS CONTINUES TO LOOK TOO WARM FOR THE PLAINS...SO HAVE STAYED ON
THE COOL SIDE OF GUIDANCE...PARTICULARLY SUNDAY AS HIGH CLOUDS START
MOVING IN FROM THE WEST.
SOME MODEL DISCREPANCIES FOR OUR FIRST SHORT WAVE LATE SUNDAY. THE TREND
HAS BEEN TOWARDS A SLIGHTLY DEEPER OR SHARPER TROUGH...WHICH THE
ECMWF HAS BEEN ADVERTISING FOR A WHILE NOW. THE GFS NOW LOOKS
COOLER AND WETTER...AND WOULD BRING SEVERAL INCHES OF SNOW TO THE AREA
ABOVE 9K FEET SUNDAY NIGHT. THE NAM IS CONSIDERABLY WARMER AND
PROBABLY WOULD JUST LEAD TO TRACE SNOW AMOUNTS. THE TRUTH LIKELY IS
SOMEWHERE IN BETWEEN...BUT PROBABLY CLOSER TO THE GFS. SHOULD KNOW
BETTER BY TOMORROW OR FRIDAY IF THE NAM MOVES TOWARD A COOLER
SOLUTION. HAVE BUMPED UP POPS ABOUT 10-20 PERCENT AREA WIDE AS THE
TROUGH MOVES THROUGH SUN NIGHT.
MONDAY AND TUESDAY...THINGS REALLY DRY OUT IN ZONAL FLOW...AND WE
SHOULD SEE SOME REAL PLEASANT FALL WEATHER WITH LOTS OF SUNSHINE
AND TEMPS IN THE 70S-NR 80 FOR THE LOWLANDS AND 60S FOR THE HIGHER
VALLEYS. POPS ESSENTIALLY NIL EVEN FOR THE MTS.
NEXT SYSTEM BEGINS TO TAKE SHAPE ON WED THROUGH THU AS A DEEPER TROUGH
MOVES THROUGH THE PACNW AND INTO THE INTER-MOUNTAIN REGION. STILL PLENTY
OF UNCERTAINTY WITH THE TIMING AND DEPTH OF THIS LOW...BUT THE
TREND FOR A WHILE NOW HAS BEEN FOR IT TO LIFT INTO THE NRN ROCKIES
BY LATE THU OR FRI...WHICH WOULD BRING MOST OF THE PRECIP N OF OUR
CWA AND LEAVE US IN A DRY AND BREEZY CORNER. CERTAINLY DOES NOT
LOOK LIKE A BIG STORM FOR OUR AREA...BUT THE MTS SHOULD SEE AT
LEAST SOME LIGHT SNOWFALL ABOVE 9 OR 10K FEET AS H7 TEMPS DROP
CLOSE TO ZERO BY THE END OF THE WEEK. ROSE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 317 PM MDT THU SEP 19 2013
ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AND SPREAD OFF INTO THE ADJACENT PLAINS DURING THE
AFTERNOON AND EARLY EVENING. THE MAIN THREAT WITH THUNDERSTORMS
WILL BE SOME BRIEF MODERATE RAINFALL AND WIND GUSTS TO AROUND 40
KTS...AS WELL AS LIGHTNING. OVERNIGHT...WINDS ACROSS THE PLAINS
WILL SHIFT AROUND FROM THE SOUTHEAST WITH WIDESPREAD STRATUS AND
AREAS OF FOG AND PATCHY DRIZZLE DEVELOPING ALONG THE LOWER EASTERN
SLOPES OF THE SOUTHEAST MTS AND I-25 CORRIDOR AFTER 06Z. EXPECT
IFR TO LIFR CIGS/VIS FOR KCOS AND KPUB TO DEVELOP AFTER 06Z WITH
THE LOWEST CIGS/VIS ACROSS SOUTHERN EL PASO COUNTY INCLUDING KCOS.
CIGS WILL BE SLOW TO BREAK ACROSS THE SE PLAINS ON
FRIDAY...PARTICULARLY FOR KCOS DUE TO PERSISTENT SOUTHERLY FLOW.
CIGS MAY LIFT INTO THE MVFR TO IFR CATEGORY AROUND 18Z...BEFORE
CLEARING AFTER THAT. KALS WILL REMAIN UNDER VFR CONDITIONS THROUGH
THE NIGHT. THERE IS A LOW PROBABILITY FOR A REPEAT THREAT FOR FOG
OVERNIGHT AT KALS...BUT CHANCES LOOK TOO LOW TO WARRANT MENTION IN
TAFS AT THIS POINT. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...ROSE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1034 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
COLD FRONT IS NOW LOCATED ALONG I-70 AND IS EXPECTED TO CONTINUE
DROPPING SEWRD TO NEAR THE SAN JUAN MOUNTAINS BEFORE WASHING OUT.
THE UPPER LEVEL TROUGH IS LAGGING BEHIND THE SFC FRONT AND IS JUST
ENTERING WRN CO AT THIS HOUR. AHEAD OF THE TROUGH...RADAR PICKING
UP SOME RETURNS N OF I-70 WITH A FEW STRAY STORMS ALSO FORMING
THANKS TO UPPER LEVEL SUPPORT AND OROGRAPHIC LIFT. EXPECT THIS TO
CONTINUE THROUGH DAYBREAK WITH SOME MIDLEVEL CLOUDS AROUND THE
AREA FOR THE COMMUTE TO WORK. 00Z NAM12 SHOWED SOME VERY ISOLD
SHOWERS OVER CENT/SRN MTNS THIS AFTERNOON DUE TO LIMITED MOISTURE
AND SOME OROGRAPHICS WHILE 06Z NAM12 HAS ALL BUT REMOVED THEM.
LATEST HRRR AND RAP13 GUIDANCE ALSO SHOWING A DISTINCT LACK OF
PRECIP FOR THE ENTIRE CWA TODAY. NOT SOLD ON IDEA THOUGH AS SOME
MARGINAL INSTABILITY EXISTS ALONG WITH SOME MOISTURE IN LOWER
LEVELS. FOR NOW...WILL LEAVE ISOLD CONVECTION IN FORECAST FOR THE
HIGHEST TERRAIN IN THE SAN JUANS AND CENTRAL MTNS. MOST AREAS
TODAY WILL SEE SUN...SUN...AND MORE SUN AND MORE FALL LIKE
TEMPERATURES AS A PATTERN SHIFT FINALLY SETS UP.
ANY LINGERING SHOWER OR STORM NEAR THE CENTRAL OR SOUTHERN DIVIDE
WILL QUICKLY DIMINISH THIS EVENING WITH SUNSET. WEAK WARM ADVECTION
ALOFT THEN COMMENCES TONIGHT AS A PROGRESSIVE UPPER RIDGE
APPROACHES...BUT IT WILL NOT LIKELY BE ENOUGH TO OFFSET RADIATIONAL
COOLING DUE TO CLEAR SKIES AND DRIER AIR. HENCE...A COOL NIGHT LOOKS
IN STORE WITH POCKETS OF FREEZING OR NEAR FREEZING TEMPS TO THE
LOWER VALLEYS IN THE CRAIG AND MEEKER AREAS AND WILL CONTINUE THE
FREEZE WATCH FOR THESE AREAS TONIGHT. MODELS SUGGEST THAT THE
STEAMBOAT VALLEY AND AROUND GUNNISON WILL BOTTOM OUT IN THE MID 30S.
TEMPS SHOULD WARM QUICKLY FRIDAY MORNING WITH PLENTY OF SUNSHINE.
DRY AND SUNNY CONDITIONS ARE EXPECTED FRIDAY WITH HIGH TEMPS
REBOUNDING AS THE UPPER RIDGE SLIDES ACROSS THE AREA. AFTERNOON
HUMIDITIES WILL DROP INTO THE TEENS FRIDAY AFTERNOON IN MANY OF THE
NORTHWEST AND WEST-CENTRAL COLORADO VALLEYS...AND EASTERN UTAH
VALLEYS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
FLOW ALOFT BECOMES SOUTHWEST FRIDAY NIGHT AND SATURDAY AS THE UPPER
RIDGE MOVES TO THE EAST AND A PACIFIC TROUGH PUSHES INLAND. GRADIENT
TIGHTENS SATURDAY AS THE TROUGH ADVANCES FOR STRENGTHENING AND GUSTY
SURFACE WINDS ACROSS NE UT/NW CO SATURDAY AFTERNOON...AND TEMPS
SHOULD WARM OVER FRIDAY. NAM MODEL SHOWS MID-LEVEL MOISTURE BEING
DRAWN NORTHWARD INTO SW CO AS EARLY AS FRI NIGHT WHILE THE GFS WAITS
UNTIL SAT. THE EVENING MODELS ALSO DID SEEM QUITE AS ENTHUSIASTIC
WITH RAISING PRECIPITABLE WATER VALUES AS EARLIER RUNS. STILL...MAY
SEE A FEW SHOWERS OR THUNDERSTORMS OVER THE SAN JUANS SAT AFTERNOON
AND MADE LITTLE CHANGE TO THE CURRENT FORECAST FOR THE FIRST HALF OF
THE WEEKEND.
BIG DIFFERENCE IN LONG-TERM FOR THE WEEKEND AS PREVIOUS GFS RUNS
SHOWED MARGINAL PRECIP WITH AN APPROACHING TROUGH AND SFC COLD
FRONT WHILE LATEST RUN SHOWS SIGNIFICANT PRECIP FOR MUCH OF THE
AREA SUNDAY AFTERNOON AND NIGHT. EC ALSO SHOWING THIS PRECIP WHILE
NAM12 SHOWING VERY LITTLE AT THIS TIME. MOISTURE TRANSPORT VECTORS
ON THE 320K SURFACE DO SHOW SOME MOISTURE STREAMING UP FROM THE
SOUTH SATURDAY NIGHT INTO SUNDAY MORNING BEFORE BEING WORKED ON BY
THE TROUGH. THE TROUGH WILL BE SUPPORTED BY AN 80 KT JET STREAK
AND IT LOOKS LIKE THIS TROUGH MAY BECOME NEGATIVELY TILTED. IF YOU
PUT ALL OF THESE TOGETHER...SOME WIDESPREAD PRECIP CAN BE EXPECTED
WITH SOME STRONG THUNDERSTORMS POSSIBLE. CAN ALSO EXPECT SOME
GUSTY SFC WINDS...ESPECIALLY SUNDAY...AHEAD OF SAID FRONT. SOME
WHITE STUFF ALSO POSSIBLE AT THE HIGHEST ELEVATIONS...ABOVE 13K
FT...AS H7 TEMPS DROP TO AROUND 3C. SFC TEMPERATURES WILL DROP 8
TO 10 DEGREES FROM SATURDAY TO SUNDAY AS THE COLD FRONT PUSHES
THROUGH.
BY MONDAY MORNING...THE TROUGH AND FRONT WILL HAVE EXITED OUR AREA
ALLOWING ZONAL FLOW TO SET UP BRINGING A PERIOD OF DRY WEATHER AND
SEASONAL TEMPERATURES THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1034 AM MDT THU SEP 19 2013
VFR CONDITIONS WILL CONTINUE OVER THE REGION THROUGH THE NEXT 24
HOURS AS DRIER AIR BRINGS QUIET WEATHER TO REGION. A FEW
THUNDERSTORMS REMAIN A POSSIBILITY OVER THE RIDGES ALONG THE
CONTINENTAL DIVIDE FROM 19Z THROUGH 01Z FRIDAY. THIS ACTIVITY WILL
RESULT IN BRIEF AND LOCALIZED RIDGE AND PEAK OBSCURATIONS AND
SHOULD NOT AFFECT AIRPORT FLIGHT OPERATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ002.
UT...NONE.
&&
$$
SHORT TERM...TGR/JAD
LONG TERM...JAD/TGR
AVIATION...NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
313 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
COLD FRONT IS NOW LOCATED ALONG I-70 AND IS EXPECTED TO CONTINUE
DROPPING SEWRD TO NEAR THE SAN JUAN MOUNTAINS BEFORE WASHING OUT.
THE UPPER LEVEL TROUGH IS LAGGING BEHIND THE SFC FRONT AND IS JUST
ENTERING WRN CO AT THIS HOUR. AHEAD OF THE TROUGH...RADAR PICKING
UP SOME RETURNS N OF I-70 WITH A FEW STRAY STORMS ALSO FORMING
THANKS TO UPPER LEVEL SUPPORT AND OROGRAPHIC LIFT. EXPECT THIS TO
CONTINUE THROUGH DAYBREAK WITH SOME MIDLEVEL CLOUDS AROUND THE
AREA FOR THE COMMUTE TO WORK. 00Z NAM12 SHOWED SOME VERY ISOLD
SHOWERS OVER CENT/SRN MTNS THIS AFTERNOON DUE TO LIMITED MOISTURE
AND SOME OROGRAPHICS WHILE 06Z NAM12 HAS ALL BUT REMOVED THEM.
LATEST HRRR AND RAP13 GUIDANCE ALSO SHOWING A DISTINCT LACK OF
PRECIP FOR THE ENTIRE CWA TODAY. NOT SOLD ON IDEA THOUGH AS SOME
MARGINAL INSTABILITY EXISTS ALONG WITH SOME MOISTURE IN LOWER
LEVELS. FOR NOW...WILL LEAVE ISOLD CONVECTION IN FORECAST FOR THE
HIGHEST TERRAIN IN THE SAN JUANS AND CENTRAL MTNS. MOST AREAS
TODAY WILL SEE SUN...SUN...AND MORE SUN AND MORE FALL LIKE
TEMPERATURES AS A PATTERN SHIFT FINALLY SETS UP.
ANY LINGERING SHOWER OR STORM NEAR THE CENTRAL OR SOUTHERN DIVIDE
WILL QUICKLY DIMINISH THIS EVENING WITH SUNSET. WEAK WARM ADVECTION
ALOFT THEN COMMENCES TONIGHT AS A PROGRESSIVE UPPER RIDGE
APPROACHES...BUT IT WILL NOT LIKELY BE ENOUGH TO OFFSET RADIATIONAL
COOLING DUE TO CLEAR SKIES AND DRIER AIR. HENCE...A COOL NIGHT LOOKS
IN STORE WITH POCKETS OF FREEZING OR NEAR FREEZING TEMPS TO THE
LOWER VALLEYS IN THE CRAIG AND MEEKER AREAS AND WILL CONTINUE THE
FREEZE WATCH FOR THESE AREAS TONIGHT. MODELS SUGGEST THAT THE
STEAMBOAT VALLEY AND AROUND GUNNISON WILL BOTTOM OUT IN THE MID 30S.
TEMPS SHOULD WARM QUICKLY FRIDAY MORNING WITH PLENTY OF SUNSHINE.
DRY AND SUNNY CONDITIONS ARE EXPECTED FRIDAY WITH HIGH TEMPS
REBOUNDING AS THE UPPER RIDGE SLIDES ACROSS THE AREA. AFTERNOON
HUMIDITIES WILL DROP INTO THE TEENS FRIDAY AFTERNOON IN MANY OF THE
NORTHWEST AND WEST-CENTRAL COLORADO VALLEYS...AND EASTERN UTAH
VALLEYS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
FLOW ALOFT BECOMES SOUTHWEST FRIDAY NIGHT AND SATURDAY AS THE UPPER
RIDGE MOVES TO THE EAST AND A PACIFIC TROUGH PUSHES INLAND. GRADIENT
TIGHTENS SATURDAY AS THE TROUGH ADVANCES FOR STRENGTHENING AND GUSTY
SURFACE WINDS ACROSS NE UT/NW CO SATURDAY AFTERNOON...AND TEMPS
SHOULD WARM OVER FRIDAY. NAM MODEL SHOWS MID-LEVEL MOISTURE BEING
DRAWN NORTHWARD INTO SW CO AS EARLY AS FRI NIGHT WHILE THE GFS WAITS
UNTIL SAT. THE EVENING MODELS ALSO DID SEEM QUITE AS ENTHUSIASTIC
WITH RAISING PRECIPITABLE WATER VALUES AS EARLIER RUNS. STILL...MAY
SEE A FEW SHOWERS OR THUNDERSTORMS OVER THE SAN JUANS SAT AFTERNOON
AND MADE LITTLE CHANGE TO THE CURRENT FORECAST FOR THE FIRST HALF OF
THE WEEKEND.
BIG DIFFERENCE IN LONG-TERM FOR THE WEEKEND AS PREVIOUS GFS RUNS
SHOWED MARGINAL PRECIP WITH AN APPROACHING TROUGH AND SFC COLD
FRONT WHILE LATEST RUN SHOWS SIGNIFICANT PRECIP FOR MUCH OF THE
AREA SUNDAY AFTERNOON AND NIGHT. EC ALSO SHOWING THIS PRECIP WHILE
NAM12 SHOWING VERY LITTLE AT THIS TIME. MOISTURE TRANSPORT VECTORS
ON THE 320K SURFACE DO SHOW SOME MOISTURE STREAMING UP FROM THE
SOUTH SATURDAY NIGHT INTO SUNDAY MORNING BEFORE BEING WORKED ON BY
THE TROUGH. THE TROUGH WILL BE SUPPORTED BY AN 80 KT JET STREAK
AND IT LOOKS LIKE THIS TROUGH MAY BECOME NEGATIVELY TILTED. IF YOU
PUT ALL OF THESE TOGETHER...SOME WIDESPREAD PRECIP CAN BE EXPECTED
WITH SOME STRONG THUNDERSTORMS POSSIBLE. CAN ALSO EXPECT SOME
GUSTY SFC WINDS...ESPECIALLY SUNDAY...AHEAD OF SAID FRONT. SOME
WHITE STUFF ALSO POSSIBLE AT THE HIGHEST ELEVATIONS...ABOVE 13K
FT...AS H7 TEMPS DROP TO AROUND 3C. SFC TEMPERATURES WILL DROP 8
TO 10 DEGREES FROM SATURDAY TO SUNDAY AS THE COLD FRONT PUSHES
THROUGH.
BY MONDAY MORNING...THE TROUGH AND FRONT WILL HAVE EXITED OUR AREA
ALLOWING ZONAL FLOW TO SET UP BRINGING A PERIOD OF DRY WEATHER AND
SEASONAL TEMPERATURES THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 310 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE PREDOMINANT AT THIS HOUR AND THESE CONDITIONS
WILL CONTINUE FOR THE NEXT 24 HOURS. A SLIGHT CHANCE EXISTS FOR
SOME CONVECTION TO FIRE OVER THE HIGHER ELEVATIONS OF THE SAN
JUANS AND CENTRAL MOUNTAINS BUT NO EFFECTS TO TAF SITES EXPECTED.
SOME MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH DAYBREAK TODAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ002.
UT...NONE.
&&
$$
SHORT TERM...TGR/JAD
LONG TERM...JAD/TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS MIAMI FL
227 PM EDT THU SEP 19 2013
.SHORT TERM (TONIGHT-SATURDAY NIGHT)...
THIS EVENING...THE LATEST RADAR SCAN SHOWED SCATTERED ACTIVITY
DEVELOPING OVER THE INTERIOR AREAS SPREADING WESTWARD TOWARD THE
GULF COAST. THE LATEST HRRR MODEL RUNS LINE UP WELL WITH THIS AND
INDICATE THIS ACTIVITY BECOMING FOCUSED OVER AND AROUND THE GULF
COAST AREAS THROUGH THE LATE AFTERNOON AND EVENING HOURS ONCE AGAIN.
CONSIDERING THE EXTENSIVE RAINFALL COVERAGE OVER THE GULF COAST
YESTERDAY...THE MAIN CONCERN THROUGH THIS EVENING WILL BE THE
POTENTIAL FOR ADDITIONAL HEAVY RAINFALL AND FLOODING DUE TO THE
SATURATED GROUNDS.
FRIDAY THROUGH SATURDAY NIGHT...THE LATEST NUMERICAL GUIDANCE
REMAINS IN DECENT AGREEMENT THROUGH THIS PERIOD AND SHOWS WHAT IS
LEFT OF THE WEAKENING BOUNDARY OR TROUGH CURRENTLY MOVING INTO
THE AREA CONTINUING SOUTH WITH SOME DRIER AIR FILLING IN BEHIND IT
FROM THE NORTH. THIS COMBINED WITH THE MEAN LOW-LEVEL FLOW UP TO
10 KFT SHIFTING TO THE NORTH WILL TRANSLATE TO LOWER RAINFALL
CHANCES EACH DAY. DEWPOINTS COULD REACH THE LOWER 60S ACROSS
PORTIONS OF THE INTERIOR AREAS SATURDAY AFTERNOON. MODEL SOUNDINGS
INDICATE PRECIPITABLE WATER VALUES DIPPING DOWN TO AROUND 1.3"
ACROSS PORTIONS OF THE AREA BY SATURDAY. TEMPERATURES ARE FORECAST
TO REMAIN AROUND NORMAL THROUGH THIS PERIOD...WITH THE EXCEPTION
BEING THE POSSIBILITY OF REACHING THE UPPER 60S ACROSS THE
NORTHERN INTERIOR AREAS BY DAYBREAK SATURDAY MORNING.
.LONG TERM (SUNDAY-WEDNESDAY)...
AN UPPER TROUGH IS FORECAST TO DIG ACROSS THE SOUTHEAST AND
EASTERN SEABOARD THROUGH THE SECOND HALF OF THE WEEKEND. OUT AHEAD
OF THIS...SURFACE AND LOW LEVEL FLOW WILL SHIFT TO THE
SOUTH...BRINGING A SURGE OF MOISTURE BACK INTO SOUTH FLORIDA ON
SUNDAY. MODELS HAVE BEEN TRENDING TOWARDS A WEAKER LOW LEVEL/SURFACE
REFLECTION ACROSS THE SOUTHEAST...AND THUS A WEAKER COLD FRONT
MOVING INTO THE SOUTHEAST STATES. THE ECMWF IS NOW STRONGER THAN THE
GFS WITH THE BAROCLINIC SURFACE LOW ACROSS THE NORTHERN GULF
COAST/SOUTHEAST STATES...AND DRAWS THE MOISTURE FROM THE BAY OF
CAMPECHE SYSTEM TO THE NORTHEAST. REGARDLESS...SINCE THE MODELS HAVE
TRENDED SLOWER WITH THE COLD FRONT AND KEEP IT ACROSS NORTH FLORIDA
THROUGH EARLY NEXT WEEK...THE FOCUS FOR STORMS MAY BE ACROSS THE
GULF WATERS AND NORTH OR CENTRAL FLORIDA. WITH NO FOCUS FOR RAINFALL
ACROSS SOUTH FLORIDA AND EXTENSIVE CLOUD COVER POSSIBLY LIMITING
RAINFALL AMOUNTS DURING THE DAY MONDAY AND TUESDAY...THE HEAVIEST
RAINS MAY ACTUALLY FALL OVER THE NIGHT TIME HOURS AS SPEED/COASTAL
CONVERGENCE SETS UP. THE GFS AND ECMWF ARE HINTING AT THIS AS
WELL. SO RAINFALL CHANCES WILL LIKELY REMAIN HIGH SUNDAY THROUGH
TUESDAY. THE FORECAST IS UNCLEAR BEYOND THAT POINT...BUT RAINFALL
CHANCES WILL REMAIN ELEVATED THROUGH AT LEAST WEDNESDAY.
&&
.AVIATION...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP THROUGH THE AFTERNOON ACROSS THE INTERIOR AND MOVE TOWARDS
KAPF WITH A FEW SHOWERS ALONG THE EAST COAST. SEA BREEZES ALONG BOTH
COASTS UNTIL EARLY THIS EVENING. MOST CONVECTION SHOULD DIMINISH BY
00Z WITH DRIER AIR MOVING INTO THE AREA THROUGH EARLY FRIDAY.
&&
.MARINE...
LIGHT TO MODERATE NORTHEAST WINDS WILL CONTINUE THROUGH SATURDAY AS
A WEAKENING FRONTAL BOUNDARY SHIFTS SOUTH INTO THE AREA. WINDS WILL
SHIFT TO THE SOUTH THROUGH THE SECOND HALF OF THE WEEKEND AND INTO
EARLY NEXT WEEK AS ANOTHER FRONTAL BOUNDARY APPROACHES FROM THE
NORTH. SEAS OVER THE ATLANTIC WATERS SHOULD BEGIN TO SUBSIDE OVER
THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 88 74 88 / 20 20 10 10
FORT LAUDERDALE 76 88 77 89 / 20 20 10 10
MIAMI 76 89 75 89 / 20 20 10 10
NAPLES 73 90 73 90 / 30 20 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 PM CDT THU SEP 19 2013
.DISCUSSION...
338 AM CDT
THE FORECAST CHALLENGES ARE CENTERED ON THE NEXT 36 HOURS AS
AN UNSEASONABLY WARM AND MOIST AIR MASS FOR LATTER SEPTEMBER IN
PLACE WILL KEEP THE POTENTIAL FOR STORMS THROUGH TODAY AND AID IN
ACTIVITY ALONG A COLD FRONT MOVING THROUGH LATER TONIGHT AND
FRIDAY.
THIS MORNING...PESKY MCV IS CENTERED OVER NORTHERN IN THIS
MORNING AFTER ITS 18-24 HOUR EASTWARD TRACK OF TROUBLE FROM
CENTRAL IA YESTERDAY MORNING. THE STORM ACTIVITY OF YESTERDAY AND
LAST NIGHT KEPT THE LOW-LEVEL WARM FRONT FROM DEVELOPING TOO
QUICKLY NORTHWARD...SO THAT IS ROUGHLY ANALYZED FROM A 1001MB LOW
ACROSS EASTERN SD THROUGH SOUTHERN MN AND INTO THE WESTERN AND
SOUTHERN FORECAST AREA. WARM AIR ADVECTION INDUCED ASCENT NORTH OF
THIS HAS ONCE AGAIN SPARKED CONVECTION IN THE FAST PACED WSW MID-
LEVEL FLOW EARLY THIS MORNING...THIS TIME ACROSS SW WI/NE IA/NW
IL. A SUBTLE SHORT WAVE IS NOTED IN WATER VAPOR AND ANALYZED BY
HIGH RES MODELS AS WELL. AS THE LOW-LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT VEER EASTWARD THIS MORNING...SOME OF THIS
ACTIVITY SHOULD FEED ON INSTABILITY AND TRAVERSE THE FORECAST AREA
AHEAD OF THE WAVE. AMDAR SOUNDING FROM ROCKFORD EARLY THIS MORNING
SHOWED 1300 J/KG OF ELEVATED CAPE WHEN LIFTING FROM 850MB...SO
SOME FUEL THERE FOR STORMS AND POSSIBLY A COUPLE STRONGER ONES
CAPABLE OF SMALL HAIL...GUSTY WINDS...AND VERY EFFICIENT RAINFALL.
EXPECT THE ACTIVITY TO MOVE MAINLY EAST OF THE FORECAST AREA BY
LATE MORNING/EARLY AFTERNOON WITH WARM AIR ADVECTION CLOUDS
SCATTERING.
THIS AFTERNOON...THE THERMAL RIDGE AHEAD OF THE SYSTEM COLD FRONT
DEVELOPS NORTHEAST OVER THE AREA THIS PERIOD AND IS ROBUST FOR
THIS TIME OF YEAR...WITH 850MB TEMPERATURES OF 18C-20C FROM EAST
TO WEST ACROSS THE CWA. LOCAL CLIMATOLOGY SUPPORTS HIGHS AROUND
90...OR IN OTHER WORDS WITHIN 5F OF RECORD HIGHS FOR TODAY. SOME
OF THE MORNING CLOUDS...ESPECIALLY ACROSS THE NORTHEAST FORECAST
AREA WHERE THEY MAY LAST THE LONGEST...WILL HINDER THAT SOME.
OTHERWISE GOING FORECAST HIGHS CONTINUE TO LOOK GOOD AND ARE
SUPPORTED BY SOME OF THE BEST VERIFYING GUIDANCE ON WARM DAYS
WITHIN THIS PAST MONTH. IF STORMS FESTER FOR LONGER THIS
MORNING AND CONTINUE INTO AFTERNOON...THEN GOING FORECAST IS TOO
HIGH BY SEVERAL DEGREES. WHILE MLCAPES ARE FORECAST TO BUILD TO
2000-2500 J/KG ACROSS THE CWA LIKELY ERODING CIN BY MID TO LATE
AFTERNOON...THE FOCUS OF PRE-FRONTAL CONVERGENCE AND SHORT WAVE
ENERGY STILL MAINLY LOOKS TO BE AFTER 00Z. BUT THIS IS A HIGH PWAT
WARM SECTOR WITH LIMITED CAPPING AND AS YESTERDAY SHOWED...EVEN
SOMETHING SUBTLE CAN CAUSE PROBLEMS. SO START INCHING UP POPS IN
THE WESTERN CWA LATE THIS AFTERNOON. IF STORMS CAN MAKE IT IN THAT
EARLY...SCATTERED SEVERE POTENTIAL IS THERE GIVEN JUST THE
INSTABILITY AND PWATS.
TONIGHT AND FRIDAY...THE SURFACE LOW WILL DEVELOP NORTHEASTWARD
INTO ONTARIO TONIGHT STEERING THE COLD FRONT INTO THE WESTERN
FORECAST AREA LIKELY BY AROUND DAYBREAK FRIDAY. FOCUS FOR
CONVECTION REMAINS GOOD...ESPECIALLY FOR THE WESTERN FORECAST AREA
THIS EVE INTO EARLY OVERNIGHT. A SCATTERED SEVERE THREAT EXISTS
EVEN WITH MARGINAL DEEP LAYER SHEAR. MUCH LIKE YESTERDAY...THE
THREATS FROM LIKELY MULTI-CELL OR SOMEWHAT LINEAR ACTIVITY THAT
COULD REACH SEVERE LIMITS WOULD BE VERY HEAVY RAINFALL...GUSTY
WINDS...AND HAIL. SOME INDICATION IN BOTH THE 19.00 NAM AND GFS
THAT THE BEST DEEP CONVERGENCE SORT OF SPLITS THE EASTERN FORECAST
AREA AS THE BOUNDARY ADVANCES...AND SEVERAL CONVECTIVE ALLOWING
GUIDANCE MEMBERS DO SHOW A GENERAL DECREASE IN REFLECTIVITY INTO
THE OVERNIGHT. THINK THAT MAY BE A LITTLE TOO EAGER TO DIMINISH
CONVECTION GIVEN THE PWATS AT TWO STANDARD DEVIATIONS ABOVE NORMAL
AND A WELL-DEFINED COLD FRONT MOVING INTO THAT AIR MASS. SO STILL
HAVE MAINTAINED HIGH POPS EVEN FURTHER EAST LATE INTO THE NIGHT
AND INTO FRIDAY MORNING. DID ADD MENTION OF HEAVY RAIN IN THE
WESTERN FORECAST AREA GIVEN THE HIGH LIKELIHOOD OF RAIN IN A MOIST
AND REPLENISHING AIR MASS. THANKFULLY THAT AREA DID NOT RECEIVE
THE HIGHER RAIN YESTERDAY. A REGENERATION OF STRONGER CONVECTION
ON FRIDAY LOOKS POSSIBLE...BUT MAINLY EAST OF THE FORECAST AREA ON
THE MEAN OF MODEL GUIDANCE. COULD SEE A LITTLE SLOW DOWN
AGAIN...BUT AT THIS POINT NOT TOO CONCERNED ON A SEVERE THREAT
FRIDAY IN OUR CWA. MORE SO IT WOULD STILL BE THE HEAVY RAIN
POTENTIAL. MILD TEMPERATURES TONIGHT LOOK TO CLIMB TO THE MID 70S
TO 80 ON FRIDAY AS THE COLD AIR ADVECTION ENSUES ALOFT.
SATURDAY AND BEYOND...GIVEN ACTIVE SHORT TERM WEATHER HAVE GONE
WITH A SMART CONSENSUS BLEND DURING THIS TIME. WITH 850MB
TEMPERATURES FORECAST BY THE NAM/GFS/EC OF 3C-5C OVER LAKE MI...SOME
LAKE EFFECT CLOUDS ARE LIKELY SATURDAY NIGHT INTO EARLY SUNDAY
INTO NW IN/NE IL AS THE WINDS VEER NNE OVER THE LAKE. OVER LAND
SATURDAY NIGHT CONDITIONS SHOULD BE CLOSER TO CALM. SO THAT SPELLS
WHAT COULD BE QUITE AN IMPRESSIVE TEMPERATURE CONTRAST ACROSS
CHICAGOLAND AND HAVE THAT AT ALMOST 20F IN THE FORECAST SUNDAY
MORNING...WITH LOWS AROUND 39F IN AURORA WHILE 58F DOWNTOWN
CHICAGO. THE SURFACE HIGH MOVES EASTWARD EARLY NEXT WEEK WITH VERY
GRADUALLY DEVELOPING WARM AIR ADVECTION. TEMPERATURES ARE FORECAST
TO INCH UP A COUPLE DEGREES EACH DAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MAIN CONCERN IS TIMING AND EXTENT OF ADDITIONAL CONVECTION
TODAY...HOPING IT HOLDS OFF UNTIL AFTER EVENING RUSH.
* IN THE SHORT TERM THE WINDS SHOULD BE TURNING SOUTHWEST AND
INCREASING BUT EFFECTS OF EARLIER CONVECTION ARE STILL BEING FELT.
* LINGERING MVFR VSBY EXPECTED TO IMPROVE SHORTLY.
LENNING
//DISCUSSION...UPDATED 18Z...
CONVECTION THAT MOVED THROUGH THIS MORNING HAS EXITED THE
TERMINALS TO THE EAST. SATELLITE PICS AND UPSTREAM OBS SUGGEST
CONDITIONS SHOULD BE IMPROVING RAPIDLY EARLY THIS AFTERNOON BEFORE
ADDITIONAL CONVECTION DEVELOPS WITH AN APPROACHING COLD FRONT THIS
EVENING. THERE IS A CHANCE OF SEEING SOME TSRA DEVELOPMENT THIS
AFTERNOON EARLIER THAN DEPICTED IN THE 18Z TAFS...BUT FCST MODELS
MATCH LATEST RADAR TRENDS IN KEEPING THE BULK OF THE ACTIVITY
ALONG OR BEHIND THE FRONT WHICH ARRIVES WELL AFTER MIDNIGHT.
UNFORTUNATELY THINGS COULD START SLOW AGAIN TOMORROW MORNING
BEFORE PRECIP COMES TO AN END WITH POSTFRONTAL WINDS VEERING
NORTHWEST AND SKIES IMPROVING.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE OF NOT SEEING ADDITIONAL TSRA BEFORE FRONTAL
TSRA ARRIVES TONIGHT.
* MEDIUM TO HIGH CONFIDENCE OF IMPROVING CONDITIONS AND SOUTHWEST
WINDS THIS AFTERNOON.
* MEDIUM CONFIDENCE ON TIMING AND EXTENT OF ACTIVITY TONIGHT.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1250 PM CDT Thu Sep 19 2013
.DISCUSSION...
ISSUED 1040 AM CDT Thu Sep 19 2013
Warm front has lifted well to the northeast of central Illinois
this morning, leaving behind partly to mostly sunny skies and very
warm temps in the upper 70s and lower 80s. Convection continues to
fire along the edge of the strengthening cap in the warm sector,
mainly from southern Lake Michigan S/SE across Indiana into the
Ohio River Valley. As warm air aloft spreads further east, this
activity will continue to shift further away from Illinois this
afternoon. End result will be a hot and mainly dry day, with
perhaps a few isolated thunderstorms. Afternoon high temps will
reach the upper 80s and lower 90s. Better thunderstorm chances
will arrive by late evening across the Illinois River Valley.
Latest HRRR shows a line of convection developing along an
advancing cold front and pushing toward the Illinois River by
around 03z. This activity should continue eastward in a weakening
state overnight.
Barnes
&&
.AVIATION...
ISSUED 1250 PM CDT Thu Sep 19 2013
Southwesterly winds gusting to around 20kt will prevail at the
KILX terminals throughout the afternoon before subsiding to around
10kt by sunset. Will see a gradual increase in mid-level
cloudiness, with BKN conditions expected by around 00z. Forecast
soundings remain rather dry through the evening before an
advancing cold front comes into the picture toward midnight. HRRR
brings scattered showers/thunder into the Illinois River Valley
after 04z...while NAM and 4km WRF-NMM are similar. All models tend
to develop a vigorous line of convection with the front late this
afternoon/early this evening well west of the Mississippi River,
then weaken it considerably as it pushes into central Illinois
overnight. For that reason, have decided to limit the convection
in the 18z TAFs. Will carry a tempo group for thunder at only KPIA
between 07z and 11z...with just predominant showers and VCTS
further east at the remaining terminals late tonight into Friday
morning. Winds will remain southwesterly overnight, then will veer
to west-northwest after FROPA Friday morning.
Barnes
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT Thu Sep 19 2013
Developing storm system over the northern Plains to be the main
issue for the forecast in the Midwest for this package. High
pressure over the Atlantic seaboard slowly sliding eastward with
southerly flow ramping up over the region in the middle of the
country. Sunshine and WAA will send temperatures well above normal
ahead of the storm system. All the warm air in place will provide
instability for advancing chances of thunderstorms through tonight
and tomorrow. Biggest issues for the forecast revolve around the
timing of the front vs. max heating, and speed of the front
itself. Ongoing convection already starting to hint that the
mesoscale influences with prefrontal trofs and outflow boundaries
will more than likely complicate the forecast of the details. Best
chances for precip tonight and through tomorrow.
SHORT TERM...Today and tomorrow...
Hot today with the ridge expanding into the Midwest. Warmest
midlevels in western CWA but will likely be countered somewhat by
advancing clouds. However, front will hold off enough to see upper
80s over majority of the area. Cold front has slowed progression
to tomorrow but convection ahead of the front and associated cold
pools will mask some of the distinction of the leading edge.
Plenty of instability in the region...but the cold front being
delayed a bit results in the FA barely clipped by the slight risk
outlook to the northwest for tonight. Frontal progression tomorrow
to be slower, and already in rain and cloud cover from the overnight
will likely inhibit intense storm development. So far tomorrow
remains in a general thunder. Overnight Friday will see a clearing
from west to east. Will need to keep an eye on guidance NW of
Interstate 55 corridor for rapid clearing may result in a need for
an adjustment of the lows down a couple degrees.
LONG TERM...Saturday through Wednesday...
Milder weather and dry through the extended. High pressure
dominates the eastern half of the country and temperatures remain
milder and closer to normal...with heat building again under a
thermal ridge in the southwestern US. With southwesterly flow
kicking in next week Tues, the extended could see some warmer
temps as time draws nearer should the pattern persist. Guidance
is still being pulled to 70s by climatology at this point.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1121 AM CDT THU SEP 19 2013
.DISCUSSION...
338 AM CDT
THE FORECAST CHALLENGES ARE CENTERED ON THE NEXT 36 HOURS AS
AN UNSEASONABLY WARM AND MOIST AIR MASS FOR LATTER SEPTEMBER IN
PLACE WILL KEEP THE POTENTIAL FOR STORMS THROUGH TODAY AND AID IN
ACTIVITY ALONG A COLD FRONT MOVING THROUGH LATER TONIGHT AND
FRIDAY.
THIS MORNING...PESKY MCV IS CENTERED OVER NORTHERN IN THIS
MORNING AFTER ITS 18-24 HOUR EASTWARD TRACK OF TROUBLE FROM
CENTRAL IA YESTERDAY MORNING. THE STORM ACTIVITY OF YESTERDAY AND
LAST NIGHT KEPT THE LOW-LEVEL WARM FRONT FROM DEVELOPING TOO
QUICKLY NORTHWARD...SO THAT IS ROUGHLY ANALYZED FROM A 1001MB LOW
ACROSS EASTERN SD THROUGH SOUTHERN MN AND INTO THE WESTERN AND
SOUTHERN FORECAST AREA. WARM AIR ADVECTION INDUCED ASCENT NORTH OF
THIS HAS ONCE AGAIN SPARKED CONVECTION IN THE FAST PACED WSW MID-
LEVEL FLOW EARLY THIS MORNING...THIS TIME ACROSS SW WI/NE IA/NW
IL. A SUBTLE SHORT WAVE IS NOTED IN WATER VAPOR AND ANALYZED BY
HIGH RES MODELS AS WELL. AS THE LOW-LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT VEER EASTWARD THIS MORNING...SOME OF THIS
ACTIVITY SHOULD FEED ON INSTABILITY AND TRAVERSE THE FORECAST AREA
AHEAD OF THE WAVE. AMDAR SOUNDING FROM ROCKFORD EARLY THIS MORNING
SHOWED 1300 J/KG OF ELEVATED CAPE WHEN LIFTING FROM 850MB...SO
SOME FUEL THERE FOR STORMS AND POSSIBLY A COUPLE STRONGER ONES
CAPABLE OF SMALL HAIL...GUSTY WINDS...AND VERY EFFICIENT RAINFALL.
EXPECT THE ACTIVITY TO MOVE MAINLY EAST OF THE FORECAST AREA BY
LATE MORNING/EARLY AFTERNOON WITH WARM AIR ADVECTION CLOUDS
SCATTERING.
THIS AFTERNOON...THE THERMAL RIDGE AHEAD OF THE SYSTEM COLD FRONT
DEVELOPS NORTHEAST OVER THE AREA THIS PERIOD AND IS ROBUST FOR
THIS TIME OF YEAR...WITH 850MB TEMPERATURES OF 18C-20C FROM EAST
TO WEST ACROSS THE CWA. LOCAL CLIMATOLOGY SUPPORTS HIGHS AROUND
90...OR IN OTHER WORDS WITHIN 5F OF RECORD HIGHS FOR TODAY. SOME
OF THE MORNING CLOUDS...ESPECIALLY ACROSS THE NORTHEAST FORECAST
AREA WHERE THEY MAY LAST THE LONGEST...WILL HINDER THAT SOME.
OTHERWISE GOING FORECAST HIGHS CONTINUE TO LOOK GOOD AND ARE
SUPPORTED BY SOME OF THE BEST VERIFYING GUIDANCE ON WARM DAYS
WITHIN THIS PAST MONTH. IF STORMS FESTER FOR LONGER THIS
MORNING AND CONTINUE INTO AFTERNOON...THEN GOING FORECAST IS TOO
HIGH BY SEVERAL DEGREES. WHILE MLCAPES ARE FORECAST TO BUILD TO
2000-2500 J/KG ACROSS THE CWA LIKELY ERODING CIN BY MID TO LATE
AFTERNOON...THE FOCUS OF PRE-FRONTAL CONVERGENCE AND SHORT WAVE
ENERGY STILL MAINLY LOOKS TO BE AFTER 00Z. BUT THIS IS A HIGH PWAT
WARM SECTOR WITH LIMITED CAPPING AND AS YESTERDAY SHOWED...EVEN
SOMETHING SUBTLE CAN CAUSE PROBLEMS. SO START INCHING UP POPS IN
THE WESTERN CWA LATE THIS AFTERNOON. IF STORMS CAN MAKE IT IN THAT
EARLY...SCATTERED SEVERE POTENTIAL IS THERE GIVEN JUST THE
INSTABILITY AND PWATS.
TONIGHT AND FRIDAY...THE SURFACE LOW WILL DEVELOP NORTHEASTWARD
INTO ONTARIO TONIGHT STEERING THE COLD FRONT INTO THE WESTERN
FORECAST AREA LIKELY BY AROUND DAYBREAK FRIDAY. FOCUS FOR
CONVECTION REMAINS GOOD...ESPECIALLY FOR THE WESTERN FORECAST AREA
THIS EVE INTO EARLY OVERNIGHT. A SCATTERED SEVERE THREAT EXISTS
EVEN WITH MARGINAL DEEP LAYER SHEAR. MUCH LIKE YESTERDAY...THE
THREATS FROM LIKELY MULTI-CELL OR SOMEWHAT LINEAR ACTIVITY THAT
COULD REACH SEVERE LIMITS WOULD BE VERY HEAVY RAINFALL...GUSTY
WINDS...AND HAIL. SOME INDICATION IN BOTH THE 19.00 NAM AND GFS
THAT THE BEST DEEP CONVERGENCE SORT OF SPLITS THE EASTERN FORECAST
AREA AS THE BOUNDARY ADVANCES...AND SEVERAL CONVECTIVE ALLOWING
GUIDANCE MEMBERS DO SHOW A GENERAL DECREASE IN REFLECTIVITY INTO
THE OVERNIGHT. THINK THAT MAY BE A LITTLE TOO EAGER TO DIMINISH
CONVECTION GIVEN THE PWATS AT TWO STANDARD DEVIATIONS ABOVE NORMAL
AND A WELL-DEFINED COLD FRONT MOVING INTO THAT AIR MASS. SO STILL
HAVE MAINTAINED HIGH POPS EVEN FURTHER EAST LATE INTO THE NIGHT
AND INTO FRIDAY MORNING. DID ADD MENTION OF HEAVY RAIN IN THE
WESTERN FORECAST AREA GIVEN THE HIGH LIKELIHOOD OF RAIN IN A MOIST
AND REPLENISHING AIR MASS. THANKFULLY THAT AREA DID NOT RECEIVE
THE HIGHER RAIN YESTERDAY. A REGENERATION OF STRONGER CONVECTION
ON FRIDAY LOOKS POSSIBLE...BUT MAINLY EAST OF THE FORECAST AREA ON
THE MEAN OF MODEL GUIDANCE. COULD SEE A LITTLE SLOW DOWN
AGAIN...BUT AT THIS POINT NOT TOO CONCERNED ON A SEVERE THREAT
FRIDAY IN OUR CWA. MORE SO IT WOULD STILL BE THE HEAVY RAIN
POTENTIAL. MILD TEMPERATURES TONIGHT LOOK TO CLIMB TO THE MID 70S
TO 80 ON FRIDAY AS THE COLD AIR ADVECTION ENSUES ALOFT.
SATURDAY AND BEYOND...GIVEN ACTIVE SHORT TERM WEATHER HAVE GONE
WITH A SMART CONSENSUS BLEND DURING THIS TIME. WITH 850MB
TEMPERATURES FORECAST BY THE NAM/GFS/EC OF 3C-5C OVER LAKE MI...SOME
LAKE EFFECT CLOUDS ARE LIKELY SATURDAY NIGHT INTO EARLY SUNDAY
INTO NW IN/NE IL AS THE WINDS VEER NNE OVER THE LAKE. OVER LAND
SATURDAY NIGHT CONDITIONS SHOULD BE CLOSER TO CALM. SO THAT SPELLS
WHAT COULD BE QUITE AN IMPRESSIVE TEMPERATURE CONTRAST ACROSS
CHICAGOLAND AND HAVE THAT AT ALMOST 20F IN THE FORECAST SUNDAY
MORNING...WITH LOWS AROUND 39F IN AURORA WHILE 58F DOWNTOWN
CHICAGO. THE SURFACE HIGH MOVES EASTWARD EARLY NEXT WEEK WITH VERY
GRADUALLY DEVELOPING WARM AIR ADVECTION. TEMPERATURES ARE FORECAST
TO INCH UP A COUPLE DEGREES EACH DAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CONVECTION MOSTLY WINDING DOWN...WITH WINDS TO VEER AND INCREASE.
* MVFR CIGS AND IFR VSBYS FOR A BIT LONGER THIS MORNING.
* ADDITIONAL TSRA TOWARD EVENING WITH AN APPROACHING FRONT.
LENNING
//DISCUSSION...UPDATED 12Z...
PRIMARY CONCERNS THROUGH THE PERIOD WILL BE PERIODIC CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING TO 20-25 KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY. THE BROAD AREA OF WARM ADVECTION AND LIFT WILL
KEEP THE CHANCES FOR SCT THUNDER OVER THE AREA FOR THE NEXT FEW
HOURS...HOWEVER...GIVED THE LACK OF A SPECIFIC FOCUSING
MECHANISM...THE ACTIVITY WILL BE SCATTERED AND LIKELY WILL NOT
IMPACT THE TERMINALS FOR A SOLID BLOCK OF TIME. SO...WILL KEEP THE
VCSH AND TEMPO GROUPS IN THE FORECAST...BUT CONFIDENCE REMAINS LOW
AS TO THE EXACT TIMING OF DIRECT IMPACT ON THE TERMINALS. THE
OTHER SIGNIFICANT CHANCE FOR THUNDER WILL COME THIS EVENING AND
THROUGH THE NIGHT AS A COLD FRONT MOVES THROUGH THE REGION. FOR
THE EVENING HOURS...THE ACTIVITY...ONCE AGAIN...WILL LIKELY BE
MORE SCATTERED...BUT AS THE COLD FRONT APPROACHES...THE ACTIVITY
SHOULD SOLIDIFY WITH A PERIOD OF PREVAILING THUNDER LIKELY. AT
THIS POINT...THE BEST CHANCE FOR PREVAILING THUNDER SHOULD BE JUST
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS. THERE SHOULD THEN
BE A PERIOD OF SOME TRAILING STRATIFORM RAIN WITH LOWER END MVFR
OR POSSIBLY IFR CIGS DEVELOPING FOR THE PRE-DAWN HOURS.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE MORNING AT ARND 10KT...AWAY FROM
THUNDER. SOME LOCALLY HIGHER GUSTS ARE POSSIBLY INVOF THUNDER. WITH
DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER GUSTS
SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT SHOULD
PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE FRONTAL
TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE SHIFTING TO NWLY WITH THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE OF MOSTLY DRY THIS AFTERNOON UNTIL FRONTAL
PRECIP ARRIVES TOWARD EVENING.
* MEDIUM CONFIDENCE IN CIG/VSBY IMPROVEMENTS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1040 AM CDT Thu Sep 19 2013
.DISCUSSION...
ISSUED 1040 AM CDT Thu Sep 19 2013
Warm front has lifted well to the northeast of central Illinois
this morning, leaving behind partly to mostly sunny skies and very
warm temps in the upper 70s and lower 80s. Convection continues to
fire along the edge of the strengthening cap in the warm sector,
mainly from southern Lake Michigan S/SE across Indiana into the
Ohio River Valley. As warm air aloft spreads further east, this
activity will continue to shift further away from Illinois this
afternoon. End result will be a hot and mainly dry day, with
perhaps a few isolated thunderstorms. Afternoon high temps will
reach the upper 80s and lower 90s. Better thunderstorm chances
will arrive by late evening across the Illinois River Valley.
Latest HRRR shows a line of convection developing along an
advancing cold front and pushing toward the Illinois River by
around 03z. This activity should continue eastward in a weakening
state overnight.
Barnes
&&
.AVIATION...
ISSUED 655 AM CDT Thu Sep 19 2013
An area of showers and thunderstorms associated with a small MCS will
mainly stay east of the central IL terminal airports this morning
from Vermilion county ese into Indiana. Carried VCSH over eastern
IL airports til 14-15Z with light fog/haze bringing visibilities
of 4-6 miles. Isolated convection possible this afternoon and
early evening as airmass become more unstable, but coverage too
limited to pinpoint down in the TAFs. VFR conditions should
generally prevail today and this evening with scattered cumulus
clouds and scattered-broken mid level clouds. A cold front
extending from 1001 mb low pressure over se part of Lake Winnipeg
through western MN thru far nw corner of IA into se Nebraska and
nw KS. Cold front slated to push se to near the IL river by PIA
around 12Z/7 am Fri. A band of showers and thunderstorms to
accompany the cold front and spread se across central IL
overnight, reaching PIA after 05Z/midnight and DEC and CMI after
09Z/4 am. MVFR ceilings and visibilities possible with convection
overnight. SSW winds around 10 kts early this morning to increase
to 10-15 kts with gusts 18-23 kts by 15Z and continue through
early evening, then be 10-14 kts tonight and gradually veer sw
overnight.
07
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT Thu Sep 19 2013
Developing storm system over the northern Plains to be the main
issue for the forecast in the Midwest for this package. High
pressure over the Atlantic seaboard slowly sliding eastward with
southerly flow ramping up over the region in the middle of the
country. Sunshine and WAA will send temperatures well above normal
ahead of the storm system. All the warm air in place will provide
instability for advancing chances of thunderstorms through tonight
and tomorrow. Biggest issues for the forecast revolve around the
timing of the front vs. max heating, and speed of the front
itself. Ongoing convection already starting to hint that the
mesoscale influences with prefrontal trofs and outflow boundaries
will more than likely complicate the forecast of the details. Best
chances for precip tonight and through tomorrow.
SHORT TERM...Today and tomorrow...
Hot today with the ridge expanding into the Midwest. Warmest
midlevels in western CWA but will likely be countered somewhat by
advancing clouds. However, front will hold off enough to see upper
80s over majority of the area. Cold front has slowed progression
to tomorrow but convection ahead of the front and associated cold
pools will mask some of the distinction of the leading edge.
Plenty of instability in the region...but the cold front being
delayed a bit results in the FA barely clipped by the slight risk
outlook to the northwest for tonight. Frontal progression tomorrow
to be slower, and already in rain and cloud cover from the overnight
will likely inhibit intense storm development. So far tomorrow
remains in a general thunder. Overnight Friday will see a clearing
from west to east. Will need to keep an eye on guidance NW of
Interstate 55 corridor for rapid clearing may result in a need for
an adjustment of the lows down a couple degrees.
LONG TERM...Saturday through Wednesday...
Milder weather and dry through the extended. High pressure
dominates the eastern half of the country and temperatures remain
milder and closer to normal...with heat building again under a
thermal ridge in the southwestern US. With southwesterly flow
kicking in next week Tues, the extended could see some warmer
temps as time draws nearer should the pattern persist. Guidance
is still being pulled to 70s by climatology at this point.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 AM CDT THU SEP 19 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA DURG THE MORNING HOURS.
* ANOTHER ROUND OF SHRA/TSRA POSSIBLE LATE THURSDAY NIGHT WITH
COLD FRONT PASSAGE.
* SLY TO SSWLY WINDS GUSTING TO ARND 20KT LATE MORNING THROUGH
EARLY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
TWO PRIMARY CONCERNS THROUGH THE PERIOD WILL BE CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING IN THE LOW 20S KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY...THERE WILL STILL BE ENOUGH FORCING TO KEEP A
CHANCE OF SHRA/TSRA IN THE TAFS. CONFIDENCE IS LOW AS TO THE
TIMING AND COVERAGE OF PCPN THIS MORNING...SO WILL KEEP THE TEMPO
GROUP IN THE FORECAST. LATEST RADAR IMAGERY ONLY INDICATES SOME
ISOLD ECHOES OVER NRN IL/IN...ASIDE FROM THE ONGOING CONVECTION
OVER NWRN INDIANA...EAST OF GYY. BUT GIVEN THE MOIST
ENVIRONMENT...WILL LEAVE THE TEMPO IN THE FORECAST FOR A LITTLE
LONGER AS THERE IS A CHANCE FOR INCREASED DEVELOPMENT THROUGH THE
MORNING HOURS. WHILE THERE MAY STILL BE LOW CHANCES FOR ADDITIONAL
SHRA/TSRA THROUGH THE AFTERNOON AND INTO EARLY
EVENING...CONFIDENCE IN TIMING AND COVERAGE IS EVEN LOWER...SO
WILL KEEP THE FORECAST DRY THROUGH THIS EVENING.
THE NEXT...MORE SIGNIFICANT CHANCE FOR SHRA/TSRA WILL COME
OVERNIGHT THURSDAY NIGHT AS A STRONG COLD FRONT APPROACHES THE
REGION. THE CONVECTIVE ACTIVITY SHOULD LARGELY BE INVOF THE
FRONT...WHICH SHOULD MOVE INTO NWRN IL BY LATE THIS EVENING AND
THEN REACH THE CHICAGO AREA TERMINALS. CONFIDENCE IS A LITTLE
HIGHER WITH THIS SYSTEM...SO HAVE ADDED A TEMPO GROUP THE END OF
THE RFD TAF...AND A PROB30 GROUP TO THE 30-HR EXTENDED PERIOD OF
THE ORD TAF. AS TIMING OF THE FRONTAL PASSAGE BECOMES A BIT MORE
CERTAIN...WILL LIKELY NEED TO CARRY A PREVAILING GROUP TSRA.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE NIGHT AT ARND 10KT. THERE IS A
CHANCE FOR SOME HIGHER GUSTINESS IF ADDITIONAL PCPN DOES DEVELOP.
WITH DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER
GUSTS SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT
SHOULD PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE
FRONTAL TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE QUICKLY SHIFTING TO NWLY WITH THE FROPA.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON SHRA/TSRA THROUGH LATE THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL SHRA/TSRA LATE THURSDAY
NIGHT INTO FRIDAY MORNING WITH THE FROPA...BUT LOWER CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1250 AM CDT THU SEP 19 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA DURG THE MORNING HOURS.
* ANOTHER ROUND OF SHRA/TSRA POSSIBLE LATE THURSDAY NIGHT WITH
COLD FRONT PASSAGE.
* SLY TO SSWLY WINDS GUSTING TO ARND 20KT LATE MORNING THROUGH
EARLY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
TWO PRIMARY CONCERNS THROUGH THE PERIOD WILL BE CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING IN THE LOW 20S KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY...THERE WILL STILL BE ENOUGH FORCING TO KEEP A
CHANCE OF SHRA/TSRA IN THE TAFS. CONFIDENCE IS LOW AS TO THE
TIMING AND COVERAGE OF PCPN THIS MORNING...SO WILL KEEP THE TEMPO
GROUP IN THE FORECAST. LATEST RADAR IMAGERY ONLY INDICATES SOME
ISOLD ECHOES OVER NRN IL/IN...ASIDE FROM THE ONGOING CONVECTION
OVER NWRN INDIANA...EAST OF GYY. BUT GIVEN THE MOIST
ENVIRONMENT...WILL LEAVE THE TEMPO IN THE FORECAST FOR A LITTLE
LONGER AS THERE IS A CHANCE FOR INCREASED DEVELOPMENT THROUGH THE
MORNING HOURS. WHILE THERE MAY STILL BE LOW CHANCES FOR ADDITIONAL
SHRA/TSRA THROUGH THE AFTERNOON AND INTO EARLY
EVENING...CONFIDENCE IN TIMING AND COVERAGE IS EVEN LOWER...SO
WILL KEEP THE FORECAST DRY THROUGH THIS EVENING.
THE NEXT...MORE SIGNIFICANT CHANCE FOR SHRA/TSRA WILL COME
OVERNIGHT THURSDAY NIGHT AS A STRONG COLD FRONT APPROACHES THE
REGION. THE CONVECTIVE ACTIVITY SHOULD LARGELY BE INVOF THE
FRONT...WHICH SHOULD MOVE INTO NWRN IL BY LATE THIS EVENING AND
THEN REACH THE CHICAGO AREA TERMINALS. CONFIDENCE IS A LITTLE
HIGHER WITH THIS SYSTEM...SO HAVE ADDED A TEMPO GROUP THE END OF
THE RFD TAF...AND A PROB30 GROUP TO THE 30-HR EXTENDED PERIOD OF
THE ORD TAF. AS TIMING OF THE FRONTAL PASSAGE BECOMES A BIT MORE
CERTAIN...WILL LIKELY NEED TO CARRY A PREVAILING GROUP TSRA.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE NIGHT AT ARND 10KT. THERE IS A
CHANCE FOR SOME HIGHER GUSTINESS IF ADDITIONAL PCPN DOES DEVELOP.
WITH DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER
GUSTS SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT
SHOULD PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE
FRONTAL TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE QUICKLY SHIFTING TO NWLY WITH THE FROPA.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON SHRA/TSRA THROUGH LATE THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL SHRA/TSRA LATE THURSDAY
NIGHT INTO FRIDAY MORNING WITH THE FROPA...BUT LOWER CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
256 PM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE DAKOTAS IS TO WEAKEN
SLIGHTLY AS IT TRACKS NORTHEAST TO SOUTHERN CANADA BY MIDDAY
THURSDAY. THE LOW THEN DEEPENS FRIDAY AND MOVES ACROSS JAMES BAY.
AN ASSOCIATED COLD FRONT WILL MOVE SOUTHEASTWARD AND ACROSS LAKE
MI DURING FRIDAY SHIFTING SOUTH AND SOUTHWESTERLY WINDS TO OUT OF
THE WEST AND NORTHWEST AND INCREASING TO STRONG BREEZES. AS LARGE
HIGH PRESSURE BUILDS SOUTHEASTWARD ACROSS THE WESTERN GREAT LAKES
FRIDAY THROUGH SUNDAY WINDS WILL GRADUALLY RELAX AS THEY VEER
THROUGH NORTH AND EAST TO SOUTHEAST.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
107 PM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR 191800Z TAF ISSUANCE/...
ISSUED AT 1259 PM EDT THU SEP 19 2013
CONVECTION HAS MOVED EAST OF THE SITES AT THIS POINT. WHILE SOME
POP UP DEVELOPMENT IS POSSIBLE YET THIS AFTERNOON/EVENING BOTH
TIMING AND PLACEMENT ARE UNCERTAIN ENOUGH TO LEAVE OUT AT THIS
TIME. MODEL SOUNDINGS SHOW PRETTY GOOD INVERSION AND LOW LEVEL
SATURATION OVERNIGHT BUT WINDS SHOULD STAY BETWEEN 5-10 KTS SO FOR
NOW WILL JUST DROP OUTLYING SITES TO MVFR FOG FOR A FEW HOURS
AFTER 9Z. A COLD FRONT WILL APPROACH TOMORROW AND WILL BRING
THUNDERSTORMS WITH IT BUT EXACT TIMING IS STILL FAR ENOUGH OUT TO
JUST INCLUDE A PROB30 AT THIS TIME. LEFT THIS OUT AT KBMG AS IT
WILL BE BEYOND THE FORECAST PERIOD THERE. ALSO EXPECT TO SEE SOME
WIND GUSTS UP TO AROUND 20 KTS BY MID MORNING OUT OF THE SOUTHWEST AHEAD
OF THE FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1045 AM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 191500Z TAF UPDATE/...
ISSUED AT 1045 AM EDT THU SEP 19 2013
RADAR LOOP SHOWS AREAS OF THUNDERSTORMS WEST OF KIND AND AROUND AND
SOUTH AND SOUTHEAST OF KBMG. THINK CONVECTIVE THREAT WILL REMAIN
RATHER HIGH ACROSS THESE TAF SITES UNTIL THIS WAVE PASSES BY AROUND
191700Z OR SO WITH CONVECTIVE THREAT EAST OF KHUF AND KLAF. BRIEF
IFR VISIBILITY/CEILING RESTRICTIONS IN THE HEAVIER SHOWERS.
OTHERWISE...AREAS OF CEILINGS AROUND 020-025 EXPECTED THIS MORNING
AS WELL...ESPECIALLY AT KLAF/KIND...WITH CEILINGS GRADUALLY LIFTING
INTO A HIGHER DECK BY THIS AFTERNOON AS WAVE PULLS OFF TO THE EAST.
OUTSIDE OF ANY CONVECTION...SURFACE WINDS GENERALLY AROUND 10 KTS OR
LESS TODAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...JAS/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1008 AM EDT THU SEP 19 2013
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 191200Z TAFS/...
ISSUED AT 725 AM EDT THU SEP 19 2013
ORGANIZED AREA OF CONVECTION CONTINUES TO DROP SOUTHEAST ACROSS THE
CENTRAL SECTIONS OF THE FORECAST AREA...AIDED BY A 25-30KT LOW LEVEL
JET. BASED ON ITS MOVEMENT...APPEARS IT SHOULD BE OUT OF THE KIND
VICINITY BY OR SHORTLY AFTER ISSUANCE TIME. ADDITIONAL CONVECTION
DEVELOPING BEHIND THIS AREA AHEAD OF AN UPPER WAVE CURRENTLY MOVING
THROUGH EASTERN ILLINOIS. THINK CONVECTIVE THREAT WILL REMAIN RATHER
HIGH ACROSS THE TAF SITES UNTIL THIS WAVE PASSES BY AROUND 191700Z
OR SO. BRIEF IFR VISIBILITY RESTRICTIONS IN THE HEAVIER SHOWERS.
OTHERWISE...SOME MVFR VISIBILITY RESTRICTIONS IN LIGHT FOG EXPECTED
TO LIFT BY THE MID MORNING HOURS. AREAS OF CEILINGS AROUND 020-025
EXPECTED THIS MORNING AS WELL...ESPECIALLY AT KLAF/KIND...WITH
CEILINGS GRADUALLY LIFTING INTO A HIGHER DECK BY THIS AFTERNOON AS
WAVE PULLS OFF TO THE EAST.
OUTSIDE OF ANY CONVECTION...SURFACE WINDS GENERALLY AROUND 10 KTS OR
LESS TODAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
459 AM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 454 AM EDT THU SEP 19 2013
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA TODAY...MAKING
IT FEEL MUCH MORE HUMID AND IT WILL BE WARMER AS WELL. A COUPLE OF
WEAK UPPER LEVEL DISTURBANCES WILL COMBINE WITH THE MOISTURE TO
PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY
AS A STRONG COLD FRONT MOVES THROUGH. TEMPERATURES WILL COOL BACK
BELOW NORMAL FOR THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 454 AM EDT THU SEP 19 2013
MESOSCALE CONVECTIVE VORTEX...MCV...WHICH MOVED OUT OF IA
YESTERDAY AND INTO IL LAST EVENING HAS BEEN SLOWLY MOVING ACROSS
NORTHERN INDIANA EARLY THIS MORNING. THIS FEATURE INTERACTED WITH
THETA E RIDGE ADVECTING ACROSS THE REGION ALONG WITH PRECIPITABLE
WATER VALUES OVER 1.5 INCHES. THE RESULT WAS SLOW MOVING
THUNDERSTORMS WITH SOME TRAINING OVER WESTERN AREAS. DUAL POL
RADAR ESTIMATES OF BETWEEN 2 AND 5 INCHES OF RAIN IN SOUTHWEST
PULASKI AND WHITE COUNTIES PROMPTED ISSUANCE OF FLASH FLOOD
WARNING AS FFG WAS AROUND 3 INCHES. RADAR SHOWING THIS PCPN
FINALLY COMING TO AN END. HOWEVER...ANOTHER LINE OF TSRA HAS
DEVELOPED ON LEADING EDGE OF SECONDARY THETA E MAX WITH LOW LEVEL
JET ADDING CONVERGENCE AND THIS LINE IS MOVING EAST. HAVE INCLUDED
SCATTERED TO NUMEROUS THUNDERSTORMS THROUGH DAYBREAK TO ACCOUNT
FOR BOTH AREAS OF PRECIPITATION. SHOULD SEE ALL ACTIVITY END/MOVE
OUT OF THE AREA SHORTLY AFTER DAYBREAK.
REMAINDER OF DAY IN FLUX AS SUBSIDENCE FROM DEPARTING MCV SHOULD
STABILIZE LOWER LEVELS. HOWEVER...BREAKS IN CLOUDS TO DEVELOP WITH
PARTLY CLOUDY EXPECTED AGAIN TODAY. 925-850MB TEMPS WARM A FEW
DEGREES FROM YESTERDAY AND HIGHS EXPECTED TO CLIMB WELL INTO 80S.
MODEST INSTABILITY DEVELOPS THIS AFTERNOON WITH PEAK HEATING AND
MOISTURE RICH AIR AS SFC DEW POINTS CLIMB INTO UPPER 60S. NAM12
SHOWING MUCAPES OVER 3000 J/KG BUT LIKELY OVERDONE GIVEN ITS
DEWPOINTS INTO LOWER 70S. HAVE TRENDED POPS DOWN TO SLIGHT CHANCE
MID MORNING INTO EARLY AFTERNOON WITH A TREND BACK UP TO LOW CHANCE
THIS AFTERNOON WITH ANY DEVELOPMENT WITH PEAK HEATING.
MODELS CONTINUE TO BE RATHER AGGRESSIVE WITH CONVECTIVE DEVELOPMENT
TONIGHT WELL AHEAD OF MAIN COLD FRONT. KEPT SIMILAR TREND OF
INCREASING POPS THROUGH THE NIGHT AS FRONT NEARS. LOCALIZED HEAVY
RAINFALL STILL POSSIBLE THROUGH THE SHORT TERM PERIOD GIVEN HIGH
PWATS AND THETA E AIR ALONG WITH TRAINING POTENTIAL.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 454 AM EDT THU SEP 19 2013
A COLD FRONT WILL BE MOVING SOUTHEAST INTO THE AREA FRIDAY.
GFS/ECMWF TELECONNECTIONS SUPPORT THE TROF STARTING TO BECOME
POSITIVELY TILTED BY LATE SATURDAY. CONCERNS FRIDAY AND FRIDAY NIGHT
FOR THUNDERSTORMS WITH HEAVY RAIN GIVEN THE LIKELIHOOD OF
BACKBUILDING CELLS. GFS BUFKIT FOR SEVERAL RUNS CONTINUES TO SHOW
MEAN CLOUD LAYER WINDS COMBINED WITH A LOW LEVEL JET FAVORING LITTLE
NET CELL MOVEMENT. ALSO FAVORING HEAVY RAIN IS THAT THE WARM CLOUD
LAYER WILL LIKELY BE GENERALLY OVER 11K FEET DEEP WITH PRECIPITABLE
WATER VALUES BETWEEN 1.7 TO 1.9 INCHES. THIS IS AROUND 2 STANDARD
DEVIATIONS AND APPROACHING THE 99TH PERCENTILE PER UPPER AIR CLIMATE
DATA. ALSO...CAPES SHOULD GENERALLY BE UNDER 1000 J/KG. THE SEVERE
WEATHER POTENTIAL LOOKS MORE MARGINAL FRIDAY GIVEN LIMITED/SKINNY
CAPES AND WEAK/STABLE MID LEVEL LAPSE RATES. HOWEVER...UPPER LEVEL
DYNAMICS INCLUDING THE TRANSLATION OF THE RIGHT ENTRANCE OF A 100+
KNOT JET SHOULD HELP TO STRENGTHEN STORMS. USED THE ECMWF/GFS TO
PUT SOME DETAIL IN THE TIMING OF THE SHOWERS AND STORMS FRIDAY.
ALSO...RAISED RAINFALL AMOUNTS GIVEN THE ABOVE REASONING.
OTHERWISE...LINGERING SHOWERS SHOULD END EARLY SATURDAY FOLLOWED BY
DRY CONDITIONS THE REST OF THE PERIOD. TRIED TO BLEND TEMPERATURES
TOWARD THE GFS OPERATIONAL RUN MEX WHICH APPEARS ON TRACK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 454 AM EDT THU SEP 19 2013
A DIFFICULT AVIATION FORECAST THIS PERIOD WITH MESOSCALE
CONVECTIVE SYSTEM OVER THE AREA AND HEADING TOWARD KFWA. MODEL
GUIDANCE STRUGGLING WITH THIS FEATURE BUT HIRES HRRR HAS A
REASONABLE HANDLE ON MOVEMENT. EXPECT SHOWERS INTO KFWA AROUND 06Z
WITH OCCASIONAL THUNDER FOR A FEW HOURS. RADAR SHOWS A TRAILING
CONVECTIVE LINE PARALLEL TO MEAN FLOW AND SHEAR VECTOR OVER
NORTHWEST INDIANA. THIS IS SLOWLY DRIFTING EAST WHILE ALSO SHOWING
SIGNS OF WEAKENING. MEANWHILE...NEW DEVELOPMENT OCCURRING OVER
LAKE MICHIGAN. HAVE INCLUDED A VCTS AT KSBN STARTING AROUND 08Z
FOR THIS ACTIVITY AND WILL MONITOR MOVEMENT FOR POSSIBLE UPDATE.
OTHERWISE SATELLITE SHOWING MID LEVEL CLOUD DECK DEVELOPING
UPSTREAM IN WARM AND MOIST SOUTHERLY FLOW. CLOUD COVER AGAIN A
PROBLEM FOR TODAY BUT EXPECT MAINLY VFR CIGS AFTER DAYBREAK WITH
AN OUTSIDE CHANCE OF SOME MVFR CIGS AFTER RAIN ENDS BEFORE
SUNRISE. CONFIDENCE LOW IN CONVECTIVE DEVELOPMENT TODAY. MOIST LOW
LEVELS BUT NO STRONG TRIGGER AND MODELS ALL OVER THE PLACE. HAVE
OPTED TO LEAVE OUT OF TAFS GIVEN UNCERTAINTY IN COVERAGE BUT A LOW
CHANCE WILL EXIST THROUGH THE PERIOD AND INTO FRIDAY WHEN STRONG
COLD FRONT ARRIVES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...LASHLEY
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
146 AM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 800 PM EDT WED SEP 18 2013
INCREASED MOISTURE WILL CONTINUE TO LIFT NORTHEAST INTO THE AREA
THROUGH THURSDAY. A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL
COMBINE WITH THIS MOISTURE TO PRODUCE A CHANCE OF SHOWERS AND
THUNDERSTORMS TONIGHT THROUGH THURSDAY NIGHT. A BETTER CHANCE OF
SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY AS A STRONGER
UPPER LEVEL SYSTEM SHIFTS INTO THE UPPER MIDWEST ALLOWING A COLD
FRONT TO APPROACH FRIDAY AFTERNOON AND EVENING. WARMER CONDITIONS
CAN BE EXPECTED THURSDAY IN ADVANCE OF THE FRONT...COOLING BACK
BELOW NORMAL FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 800 PM EDT WED SEP 18 2013
A FAIRLY COMPACT MCV HAS ALLOWED FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO BE MAINTAINED INTO NORTHWEST INDIANA THIS
EVENING. THE STRONGEST OF THESE CELLS EARLY THIS EVENING IS
LOCATED ON THE SOUTHERN PERIPHERY OF THE MCV ACROSS JASPER COUNTY
IN NORTHWEST INDIANA...BUT SHOULD GRADUALLY WEAKEN AS IT MOVES OFF
PRIMARY 500-1000 J/KG MUCAPE AXIS OVER NEXT FEW HOURS. POTENTIAL
OF SURFACE BASED INSTABILITY ALSO SHOULD WANE DURING THIS TIME
FRAME...ALTHOUGH MARGINAL CAPES ON THE ORDER OF 500 J/KG FOR
SLIGHTLY ELEVATED PARCELS SHOULD PERSIST. SCATTERED THUNDERSTORMS
HAVE ALSO DEVELOPED ON NORTHERN EDGE OF MCV ACROSS NORTHEAST
ILLINOIS...BUT CONFIDENCE REMAINS LOW THAT THESE THUNDERSTORMS
WILL SURVIVE INTO WESTERN PORTIONS OF THE AREA TOWARD MIDNIGHT. SHORT
TERM GUIDANCE IS IN FAIRLY GOOD AGREEMENT IN SECONDARY LOW LEVEL
THETAE SURGE WORKING INTO ESPECIALLY NORTHERN LOCATIONS OVERNIGHT
AS WEAK SHORT WAVE ACROSS NORTHERN IOWA TOPS THE UPPER LEVEL RIDGE
IN PLACE. THIS COULD RESULT IN ADDITIONAL ELEVATED CONVECTION
OVERNIGHT WHICH IS ALREADY COVERED IN INHERITED FORECAST WITH
SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF THE AREA. ONLY
TWEAK TO PREVIOUS FORECAST WAS TO INCREASE POPS ACROSS THE WEST
THIS EVENING TO ACCOUNT FOR MCV EVOLUTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM EDT WED SEP 18 2013
LEE CYCLOGENESIS IS NOW WELL UNDERWAY ACROSS THE NORTHERN PLAINS AS
MODERATE AMPLITUDE PV ANOMALY LIFTS OUT OF THE NORTHERN ROCKIES.
WITH A PERSISTENT SURFACE HIGH ACROSS THE EAST COAST...THIS HAS
OPENED THE DOOR FOR SOUTHWEST FLOW AND BROAD THETA-E ADVECTION
LOCALLY. VERY LITTLE FOCUS FOR SUSTAINED UVM IN THE WAKE OF THIS
MORNING`S SHORTWAVE PASSAGE THOUGH. LINGERING EFFECTS OF VERY DRY
CANADIAN AIRMASS ARE STILL BEING FELT WITH LITTLE MORE THAN AN
ISOLATED SPRINKLE ACROSS THE AREA EARLIER TODAY. CONVECTIVE LINE
ACROSS NORTHERN ILLINOIS IS EXPECTED TO DISSIPATE AS IT INTERSECTS
THIS VERY DRY AND STABLE AIRMASS LATER THIS EVENING BUT A FEW
DECAYING SHOWERS MAY BE POSSIBLE IN OUR WEST AS SUGGESTED BY SOME
PREVIOUS RUNS OF THE HRRR. THE CHANCES OF RAIN WILL THEN INCREASE
AGAIN BY LATE TONIGHT AND INTO TOMORROW BUT THE FORCING WILL
REMAIN RATHER WEAK AND BROAD. PRECIP CHANCES WILL LARGELY DEPEND
ON NOCTURNAL STRENGTHENING OF THE LLJ DRAPED ACROSS THE MIDWEST.
THOUGH THE BEST MOISTURE CONVERGENCE WILL INITIALLY BE FOCUSED
NORTHWEST OF OUR CWA...SLIGHT VEERING IS EXPECTED BY EARLY
TOMORROW MORNING WITH ANOTHER SURGE OF INCREASING
WAA/FRONTOGENESIS ACROSS OUR NORTHWEST COUNTIES. 305K SYSTEM
RELATIVE ISENTROPIC ASCENT IS NOT OVERLY IMPRESSIVE AND THERE WILL
BE A LIMITED TIME WINDOW BEFORE THE LLJ WEAKENS LATER THURSDAY
MORNING BUT SHOULD BE ENOUGH FORCING AND AVAILABLE MOISTURE TO
SUPPORT A FEW SCATTERED SHOWERS AND PERHAPS AN ISOLATED RUMBLE OF
THUNDER...MAINLY IN OUR NORTHWEST. INCREASING WAA AND ASSOCIATED
CLOUD COVER WILL ALSO LEAD TO MILD OVERNIGHT LOWS WITH VALUES
LIKELY NOT DROPPING MUCH BELOW THE LOW TO MID 60S.
SOUTHERN GREAT LAKES WILL BE FIRMLY IN THE WARM SECTOR TOMORROW.
850MB TEMPS CLIMB INTO THE UPPER TEENS...YIELDING AFTERNOON HIGHS IN
THE LOW TO MID 80S DESPITE A FAIR AMOUNT OF CLOUD COVER. CONTINUED
MOISTURE ADVECTION WILL ALSO PUSH SURFACE DEWPOINTS INTO THE MID TO
UPPER 60S...RAISING THE PROSPECTS FOR SURFACE BASED CONVECTION.
APPROACHING TROUGH AND OVERALL MODEST NATURE OF DOWNSTREAM RIDGE
RESULTS IN VERY LITTLE CAP AS WELL. FORCING WILL BE RATHER
ILL-DEFINED BUT MODEST INSTABILITY IN A REGION OF BROAD WARM/MOIST
AIR ADVECTION SHOULD SUPPORT AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS BY THE AFTERNOON. NO SEVERE WEATHER EXPECTED GIVEN
ONLY ABOUT 1500 J/KG OF SBCAPE AND 15-20 KTS DEEP LAYER SHEAR.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM EDT WED SEP 18 2013
STRONG UPR LEVEL TROF OVER THE NRN ROCKIES THIS AFTN IS EXPECTED TO
MOVE EAST TO THE UPR MS VALLEY THU NGT AND ACROSS THE GRTLKS FRI-FRI
NGT. AS THIS SYSTEM APPROACHES... MOISTURE AND LIFT SHOULD GRDLY
INCREASE FROM NW-SE ACROSS THE CWA THU NGT CAUSING SCT
SHOWERS/TSTMS. MODEST S-SW SFC GRADIENT WINDS WILL PERSIST THROUGH
THE NGT RESULTING IN MILD LOW TEMPS IN THE U60S. SFC CDFNT
ASSOCIATED WITH THIS TROF IS EXPECTED MOVE FROM NW-SE ACROSS OUR CWA
FRI AFTN-NGT WITH RAIN CHANCES PEAKING DURING THIS TIMEFRAME. GIVEN
GOOD INTRA MODEL AND RUN-RUN CONTINUITY IN THIS REGARD... HAVE
TRENDED POPS UP FRI. MODELS SUGGEST MODERATE SFC BASED INSTABILITY
WILL DVLP IN OUR AREA FRI AS STRENGTHENING 0-6KM SHEAR ASSOCIATED
WITH THE UPR TROF MOVES IN FROM THE NW. STILL APPEARS TO BE JUST A
SMALL CHC INGREDIENTS NEEDED FOR SEVERE STORMS WILL COME TOGETHER
OVER OUR AREA... WITH BULK OF STRONG SHEAR STILL FCST TO LAG
BEST INSTABILITY. LOCALLY HEAVY RAINFALL REMAINS A POSSIBILITY
FRI/FRI EVE AS PROGGED SMALL MBE VECTORS... VERY MOIST AIRMASS...
AND DEEP WARM CLOUD LAYER SUGGEST EFFICIENT RAINFALL PROCESS IN
CONVECTION WITH POTENTIAL FOR SOME TRAINING/BACKBUILDING CELLS...
THOUGH GIVEN DRY ANTECEDENT MOISTURE CONDITIONS ACROSS MOST OF OUR
CWA... EXPECT ANY FLOODING WILL BE LOCALIZED. LEANED TOWARD WARMER
MOS GUIDANCE FOR HIGHS FRIDAY AS GOOD GRADIENT MIXING OF WARM
AIRMASS EXPECTED DURING DRY PERIODS.
HIGH PRESSURE RIDGE WILL BUILD INTO THE AREA SATURDAY BRINGING ANY
LINGERING SHOWERS ERN PORTION OF CWA TO AN END EARLY WITH CAA
RESULTING IN TEMPS A BIT BLO NORMAL. THIS RIDGE IS EXPECTED TO
LINGER OVER THE WRN GRTLKS INTO THE MIDDLE OF NEXT WEEK AS ANOTHER
STRONG TROF DIGS INTO THE WRN U.S. AND A CUT-OFF LOW FORMS OVER THE
SERN U.S. AND THEN LIFTS NEWD UP THE ERN SEABOARD. THIS SHOULD
RESULT IN A PROLONGED PERIOD OF DRY WX WITH TEMPS MODERATING TO A
LITTLE ABOVE NORMAL EARLY-MIDDLE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 145 AM EDT THU SEP 19 2013
A DIFFICULT AVIATION FORECAST THIS PERIOD WITH MESOSCALE
CONVECTIVE SYSTEM OVER THE AREA AND HEADING TOWARD KFWA. MODEL
GUIDANCE STRUGGLING WITH THIS FEATURE BUT HIRES HRRR HAS A
REASONABLE HANDLE ON MOVEMENT. EXPECT SHOWERS INTO KFWA AROUND 06Z
WITH OCCASIONAL THUNDER FOR A FEW HOURS. RADAR SHOWS A TRAILING
CONVECTIVE LINE PARALLEL TO MEAN FLOW AND SHEAR VECTOR OVER
NORTHWEST INDIANA. THIS IS SLOWLY DRIFTING EAST WHILE ALSO SHOWING
SIGNS OF WEAKENING. MEANWHILE...NEW DEVELOPMENT OCCURRING OVER
LAKE MICHIGAN. HAVE INCLUDED A VCTS AT KSBN STARTING AROUND 08Z
FOR THIS ACTIVITY AND WILL MONITOR MOVEMENT FOR POSSIBLE UPDATE.
OTHERWISE SATELLITE SHOWING MID LEVEL CLOUD DECK DEVELOPING
UPSTREAM IN WARM AND MOIST SOUTHERLY FLOW. CLOUD COVER AGAIN A
PROBLEM FOR TODAY BUT EXPECT MAINLY VFR CIGS AFTER DAYBREAK WITH
AN OUTSIDE CHANCE OF SOME MVFR CIGS AFTER RAIN ENDS BEFORE
SUNRISE. CONFIDENCE LOW IN CONVECTIVE DEVELOPMENT TODAY IN WAKE OF
MCV. MOIST LOW LEVELS BUT NO STRONG TRIGGER AND MODELS ALL OVER
THE PLACE. HAVE OPTED TO LEAVE OUT OF TAFS GIVEN UNCERTAINTY IN
COVERAGE BUT A LOW CHANCE WILL EXIST THROUGH THE PERIOD AND INTO
FRIDAY WHEN STRONG COLD FRONT ARRIVES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...AGD
LONG TERM...JT
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1230 AM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 358 PM EDT WED SEP 18 2013
A BROAD UPPER LEVEL RIDGE TO OUR SOUTH IS BEING ROUNDED BY VERY
WEAK AND VERY SUBTLE UPPER LEVEL WAVES...POORLY RESOLVED BY
GUIDANCE. THESE WEAK WAVES MAY BE ABLE TO SPARK A SHOWER OR STORM
AT TIMES THROUGH LATE THURSDAY NIGHT INTO FRIDAY NIGHT...WHEN THE
MAIN FRONTAL SYSTEM WILL PUSH THROUGH THE AREA AND BRING A MORE
SUBSTANTIAL OPPORTUNITY FOR STORMS TO THE AREA BEFORE DRY AND
COOLER CONDITIONS RETURN FOR THE REMAINDER OF THE FORECAST PERIOD.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 946 PM EDT WED SEP 18 2013
RADAR LOOP SHOWS SOME STORMS IN NORTHWEST INDIANA WITH A LITTLE
SHOWER ALSO OVER NORTHERN CARROLL COUNTY. THE LARGER AREA OF
STORMS IS MOVING SOUTHEAST. LOOKING AT HRRR MODEL OUTPUT IT
APPEARS THAT THIS WILL WEAKEN AS IT HEADS THIS WAY SIMILAR TO THE
ECHOES THAT ARE NOW ONLY A BRIEF SHOWER. STILL IT LOOKS POSSIBLE
THAT STORMS COULD REACH THE NORTHERN COUNTIES OF THE AREA OVER THE
NEXT FEW HOURS AND THUS WENT WITH A SLIGHT TO LOW END CHANCE THERE
DURING THIS TIME. ALSO SEEING SOME LIGHT RAIN OVER CENTRAL
ILLINOIS PROMPTED BY A WEAK UPPER WAVE AND SOME ISENTROPIC LIFT
AND THIS COULD MOVE INTO THE AREA AFTER 6Z...SO WENT WITH A SLIGHT
CHANCE ACROSS ALL OF CENTRAL INDIANA THEN. THIS SHOULD ALSO COVER
SOME REDEVELOPMENT OVER THE NORTHEASTERN COUNTIES THAT THE HRRR IS
SHOWING...ALTHOUGH CONFIDENCE IN THIS SOLUTION IS LOW AND THUS NO
HIGHER THAN 20 POPS WILL BE USED DURING THAT TIME.
GOING LOW TEMPERATURES IN THE MIDDLE 60S LOOK GOOD BASED ON
EXPECTED CLOUD COVER AND CURRENT TEMPERATURES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 358 PM EDT WED SEP 18 2013
MAY SEE SOME SHOWERS OR STORMS DEVELOP FROM MIDDAY ONWARD
TOMORROW...AGAIN NO MORE THAN SCATTERED IN NATURE. HIGHER POPS ARE
ONLY MERITED FRIDAY INTO FRIDAY NIGHT AS THE FRONT FINALLY PUSHES
THROUGH THE AREA. SPC SEE TEXT OUTLOOK DAY 3 APPEARS REASONABLE
GIVEN THE TIME OF DAY THE FRONT IS EXPECTED...BUT INSTABILITY AND
SHEAR ARE MODEST AT BEST AND DO NOT EXPECT MUCH MORE THAN ISOLATED
SEVERE IF THAT.
ON TEMPS...CONSENSUS NUMBERS LOOKED OK THROUGHOUT GIVEN EXPECTED
THICKNESSES AND PRECIP COVERAGE...EXCEPT FOR SATURDAY WHERE A
WARMER MOS BLEND WAS PREFERRED WITH SKIES LIKELY TO CLEAR AND
AMPLE SUN EXPECTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 220 PM EDT WED SEP 18 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 190600Z TAFS/...
ISSUED AT 1230 AM EDT THU SEP 19 2013
MVFR CONDITIONS WILL BE POSSIBLE EARLY THIS MORNING. A RETURN TO VFR
IS EXPECTED BY LATE MORNING.
MODELS DEPICT A LOWERING CIGS AND VISIBILITIES DIURNALLY OVERNIGHT
AS HIGH DEW POINTS AND DIURNAL COOLING IS ONGOING. THEN MODELS ONCE
AGAIN HINT AT ANOTHER BIT OF LIFT PUSHING THROUGH THE AREA ON LATE
THIS AFTERNOON...HOWEVER...CONFIDENCE IN THIS WEAK FEATURES REMAIN
LOW AND WILL STICK WITH VFR AND VCSH ATTM. BETTER CHANCES FOR RAIN
WILL COME LATER ON FRIDAY...JUST OUTSIDE OF THE TAF FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...SMF
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1145 PM CDT WED SEP 18 2013
.UPDATE...
ISSUED AT 847 PM CDT WED SEP 18 2013
AN UPDATE WAS JUST SENT TO INCREASE POPS OVER THE NORTH HALF OF
THE AREA AFTER MIDNIGHT. LLJ PROGGED TO STRENGTHEN TO 40+KTS LATE
TONIGHT AND IS POINTED AT NORTHEAST IOWA DURING THE EARLY MORNING
HOURS. SATELLITE IMAGERY IS SHOWING AN AREA OF MID CLOUDS DRIFTING EAST
THROUGH NORTH CENTRAL IA AND THEY SHOULD BE OVER THE NE QUARTER
OF THE STATE BY MIDNIGHT...WHERE THE NOSE OF THE LLJ IS AIMED. THE
PAST SEVERAL RUNS OF THE HRRR HAVE BEEN CONSISTENTLY DEVELOPING
CONVECTION IN THE SAME AREA. GIVEN THESE FACTORS THERE WAS ENOUGH
CONFIDENCE TO INCREASE POPS INTO THE CHANCE CATEGORY BETWEEN 06Z
AND 12Z.
DLF
&&
.SYNOPSIS...
ISSUED AT 310 PM CDT WED SEP 18 2013
12Z UA ANALYSIS HAD AN 850MB LOW NEAR KBIS WITH A DEVELOPING WARM
FRONT RUNNING SOUTHEAST TO KSTL. A LLJ RAN FROM WEST TEXAS INTO
SOUTHWEST IOWA AND DEW POINTS WERE IN THE MID TEENS FROM MEXICO INTO
SOUTHERN MINNESOTA. SATELLITE/RADAR TRENDS SHOW THE SMALL COMPLEX OF
STORMS MOVING INTO NORTHEAST IOWA WITH GENERALLY CLEAR SKIES ACROSS
THE PLAINS AND IOWA.
18Z SFC ANALYSIS HAS A LOW NEAR KPIR WITH A WARM FRONT RUNNING
SOUTHEAST TO NEAR KMLI AND THEN SOUTH TO NEAR K3LF. RAIN COOLED AIR
REMAINED ACROSS NORTHEAST IOWA AND NORTHWEST ILLINOIS. DEW POINTS
WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70S IN THE
SOUTHERN PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
SATELLITE TRENDS INDICATE LITTLE IN THE WAY OF NEW CLOUDS HAVE
FORMED DURING THE AFTERNOON SO THE THREAT OF NEW CONVECTION PRIOR TO
SUNSET IS VERY LOW.
THE MCS AND LIFT TOOLS ARE SUGGESTING SOME ISOLATED WEAK CONVECTION
MAY DEVELOP OVER THE AREA BY LATE EVENING AND MOVE EAST.
HOWEVER...THE BETTER FORCING/MOISTURE IS WEST OF THE AREA. THE MCS
AND LIFT TOOLS ARE SUGGESTING ANOTHER STORM COMPLEX DEVELOPING ALONG
THE IA/MO BORDER LATE TONIGHT AND POSSIBLY ARRIVING IN THE WESTERN
CWFA AROUND SUNRISE THURSDAY. THUS MOST OF THE AREA SHOULD SEE DRY
CONDITIONS TONIGHT.
IF THE STORM COMPLEX DEVELOPS AS SUGGESTED ALONG THE IA/MO
BORDER...THEN THIS COMPLEX WOULD MOVE ACROSS THE WESTERN HALF OF THE
CWFA DURING THE MORNING. CLOUD COVER/PRECIPITATION MAY MAKE IT
DIFFICULT TO ACHIEVE HIGHS IN THE MID AND UPPER 80S THURSDAY.
NEW CONVECTION IS EXPECTED TO DEVELOP THURSDAY AFTERNOON AHEAD OF
THE APPROACHING COLD FRONT. MOISTURE LEVELS IN THE ATMOSPHERE ARE
PROJECTED TO BE QUITE HIGH UP INTO THE MID LEVELS. THUS THE
POTENTIAL FOR ANY SEVERE STORMS APPEARS TO BE LOW. ..08..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
MODERATE TO HEAVY RAIN EVENT THURSDAY NIGHT...THEN SEASONABLY COOL.
OVERVIEW...INITIALIZATION AND VERIFICATION AVERAGE WITH MOST SOLUTIONS
UNDERPLAYING MOISTURE IN CENTRAL PLAINS AND SW MONSOON PLUME. PACIFIC
ENERGY IS ALSO UNDERPLAYED WITH 10 TO 20 METER HEIGHT FALLS UNDERDONE.
THIS SHOWS UP IN SURFACE PRESSURE FIELDS. VERIFICATION AT 18Z SUPPORTS
FORCING OF HI-RES ECMWF/UKMET AND NAM-WRF WITH HI- RES ECMWF CLOSEST
ON MOISTURE FLUX WITH COOL FRONT PASSING THURSDAY NIGHT. THEN...EARLY
FALL HIGH PRESSURE TO BRING SEVERAL DAYS OF NICE LATE SEPTEMBER WEATHER
WITH LOW HUMIDITY.
THURSDAY NIGHT...STRAIGHTFORWARD FORECAST. PW/S OF 1.5" OF DEEP MOISTURE
AHEAD OF DEEP SURFACE AND UPPER LEVEL TROUGH TO BRING A LARGE SWATH
OF SHOWERS AND THUNDERSTORMS. LITTLE OR NO SURFACE WAVE SUGGESTED AT
THIS TIME...LOCAL TOOLS INDICATE ALMOST ALL THE AREA TO PICK UP .5 TO
LOCALLY NEAR 1.5 INCHES OF RAIN. WENT WITH 80-90 POPS WITH FRONT PASSING
BETWEEN MIDNIGHT AND 7 AM. DEEP MOISTURE...OVERNIGHT FORCING AND HIGH
FREEZING LEVELS DO NOT SUPPORT A SEVERE RISK AT THIS TIME WITH STRONGEST
STORMS PRODUCING MAYBE 30-40 MPH WINDS. LATER SHIFTS WILL NEED TO REASSESS
AS NAM- WRF IS TOO UNSTABLE IN BL AS HAS BEEN MORE OFTEN THE CASE THIS
WARM SEASON. NOTE: IF A WAVE FORMS...LOCALLY 2+ INCH AMOUNTS WILL BE
POSSIBLE.
FRIDAY...KEPT MORNING POPS EAST SECTIONS WITH CLEARING BY MID DAY AND
BREEZING NW WINDS OF 10-20+ MPH. HIGHS MOSTLY 70-75F FOR A NICE DAY.
FRIDAY NIGHT THROUGH WEDNESDAY...MOSTLY FAIR AND SLIGHTLY BELOW NORMAL
TEMPERATURES AS CANADIAN HIGH PRESSURE DOMINATES. HIGHS GENERALLY UPPER
60S TO MIDDLE 70S WITH LOWS 45 TO 55 DEGREES. GOOD WEATHER FOR MOST
OUTDOOR ACTIVITIES. ANOTHER PROMISING RAIN EVENT POSSIBLE BY LATE IN
THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED SEP 18 2013
THE MAIN CONCERN WILL BE THE THUNDERSTORM POTENTIAL OVERNIGHT.
THERE ARE STILL INDICATIONS OF A THUNDERSTORM COMPLEX DEVELOPING
OVER EAST CENTRAL IOWA AFTER MIDNIGHT AND MOVING NORTHEAST THROUGH
NORTHWEST IL BY THURSDAY MORNING. IT APPEARS THE BETTER FORCING
WILL BE NORTH OF I80 SO LIMITED THE MENTION OF THUNDER TO THE CID
AND DBQ TAFS BETWEEN 10Z AND 14Z. OTHERWISE EXPECT MAINLY VFR
CONDITIONS OVERNIGHT THURSDAY. A COLD FRONT WILL BE APPROACHING
THE AREA THURSDAY AFTERNOON. THUNDERSTORMS AHEAD OF THE FRONT
COULD REACH CID AND DBQ AS EARLY AS LATE THURSDAY AFTERNOON. THE
THUNDERSTORMS WILL SPREAD SOUTHEAST DURING THE EVENING. THE
STRONGEST STORMS SHOULD OCCUR LATE IN THE AFTERNOON AND EARLY IN
THE EVENING. IFR/MVFR CONDITIONS WOULD ACCOMPANY THE STRONGER STORMS.
ALSO SOUTHWEST WINDS AHEAD OF THE FRONT WILL GUST TO 20 TO 25KTS
DURING THE AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...DLF
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
223 PM CDT Thu Sep 19 2013
...Updated long term section...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 145 PM CDT THU SEP 19 2013
Based on 18z surface analysis the surface cold front was
progressing across western Kansas slightly quicker than what the
12z GFS and 12z NAM suggested. The latest HRRR and RAP seems to be
tracking the front a little better earlier this afternoon so will
follow these models for the frontal location between 21z and 00z.
Convection is expected to begin to initiate near this boundary
late day given the afternoon instability progged and improving
upper level dynamic from the left entrance region of an weak upper
level jet crossing western Oklahoma. The current distribution of
precipitation chances across south central Kansas still looks on
track so other than adjusting the location of the front, no major
adjustments to the previous forecast is anticipated late today and
early tonight. SPC mesoanalysis indicating better 0-6km shear late
today so at this time can not rule the chance of a few
thunderstorms near the Oklahoma border. Quarter size hail, gusty
winds and periods of heavy rainfall currently appear to be the
main hazard late today.
Convection across south central Kansas and near the Oklahoma
border after sunset will taper off towards midnight and skies are
expected to begin to clear from north to south. Lows tonight will
be cooler than the past few nights and based on expected 09z to
12z dewpoints will keep lows mainly in the 50s.
High pressure at the surface will build into western Kansas on
Friday as an upper level ridge builds into the western high plains
from the west. The highs on Friday are expected to climb only into
the mid to upper 70s given that both the NAM and GFS suggest a 3c-
6c decrease in 925mb-850mb temperature from 00z Thursday to 00z
Friday.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 222 PM CDT THU SEP 19 2013
Mostly clear skies and dry conditions are anticipated Friday night
through Sunday morning as an upper level ridge moves over the
Central Plains, mid levels of the atmosphere remain dry, and a dome
of high pressure slides southeast of the area. The only exception to
this will be the possibility of a few cumulus clouds around peak
heating. Winds will generally be from the northeast Friday night
shifting to more of a southerly direction Saturday into Sunday
morning. Meanwhile, an upper level shortwave will be moving through
the Western United States Saturday then into the Central Rockies
Sunday. Mid to upper level moisture will be on the increase during
the day Sunday allowing for a few clouds to form. This shortwave
will also help push a cold front through the area Sunday night. A
few thunderstorms will be possible along and ahead of this front
with winds shifting to more of a southerly direction behind it. Cold
air advection will be short lived with this front as winds shift
back to a southerly direction Monday night through Wednesday. Flow
aloft becomes more zonal (west to east) Monday night through Tuesday
then more of a southwest direction Wednesday as the next shortwave
digs into the Intermountain West. Mostly clear skies and dry
conditions are expected over Western Kansas during this timeframe
with lee troughing strengthening across eastern Colorado.
Seasonable temperatures are expected Saturday with highs around 80
degrees and lows Saturday and Sunday morning in the 50s. Highs are
then expected to reach into the lower 80s Sunday and Monday with mid
80s Tuesday and Wednesday. Lows are forecasted to range from the
upper 50s to mid 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z NAM bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 77 51 80 / 20 0 0 0
GCK 53 76 51 81 / 10 0 0 0
EHA 52 75 53 81 / 20 0 0 0
LBL 55 78 52 82 / 40 0 0 0
HYS 52 75 51 81 / 10 0 0 0
P28 60 80 53 80 / 90 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Hovorka_42
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
147 PM CDT Thu Sep 19 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 145 PM CDT THU SEP 19 2013
Based on 18z surface analysis the surface cold front was
progressing across western Kansas slightly quicker than what the
12z GFS and 12z NAM suggested. The latest HRRR and RAP seems to be
tracking the front a little better earlier this afternoon so will
follow these models for the frontal location between 21z and 00z.
Convection is expected to begin to initiate near this boundary
late day given the afternoon instability progged and improving
upper level dynamic from the left entrance region of an weak upper
level jet crossing western Oklahoma. The current distribution of
precipitation chances across south central Kansas still looks on
track so other than adjusting the location of the front, no major
adjustments to the previous forecast is anticipated late today and
early tonight. SPC mesoanalysis indicating better 0-6km shear late
today so at this time can not rule the chance of a few
thunderstorms near the Oklahoma border. Quarter size hail, gusty
winds and periods of heavy rainfall currently appear to be the
main hazard late today.
Convection across south central Kansas and near the Oklahoma
border after sunset will taper off towards midnight and skies are
expected to begin to clear from north to south. Lows tonight will
be cooler than the past few nights and based on expected 09z to
12z dewpoints will keep lows mainly in the 50s.
High pressure at the surface will build into western Kansas on
Friday as an upper level ridge builds into the western high plains
from the west. The highs on Friday are expected to climb only into
the mid to upper 70s given that both the NAM and GFS suggest a 3c-
6c decrease in 925mb-850mb temperature from 00z Thursday to 00z
Friday.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z NAM bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 77 50 80 / 20 0 0 0
GCK 53 76 50 81 / 10 0 0 0
EHA 52 75 52 81 / 20 0 0 0
LBL 55 78 51 81 / 40 0 0 0
HYS 52 75 50 80 / 10 0 0 0
P28 60 80 52 80 / 90 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Gerard
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1122 AM MDT THU SEP 19 2013
.UPDATE...
ISSUED AT 909 AM MDT THU SEP 19 2013
AREA OF PRECIPITATION CONTINUES TO MARCH EAST AHEAD OF A COLD
FRONT THAT HAS MOVED THROUGH THE WEST HALF OF THE AREA SO FAR.
BEST CHANCES FOR RAINFALL CONTINUE TO LOOK TO BE OVER THE FAR EAST
AS LIFT FROM THE COLD FRONT COMBINED WITH AN UPPER LEVEL TROUGH
WILL MOVE THROUGH AROUND NOON. BEHIND THE FRONT NORTHERLY WINDS
HAVE BECOME GUSTY...RANGING FROM 20-30 MPH WITH SOME GUSTS NEARING
40 MPH IN FAR NORTHEAST COLORADO. THE GUSTS SHOULD START TO
DECLINE BY THE EARLY AFTERNOON AS THE SURFACE PRESSURE GRADIENT
BEHIND THE FRONT SLACKENS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1119 AM MDT THU SEP 19 2013
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. CURRENT LOW CLOUDS OVER
KGLD WILL MOVE EAST AHEAD OF THE MID LEVEL TROUGH AXIS. GUSTY
WINDS WILL DECLINE GRADUALLY THROUGH EARLY AFTERNOON...BECOMING
LIGHTER BY MID AFTERNOON THEN LIGHT BY EARLY EVENING. THE LIGHT
WINDS WILL CONTINUE THROUGH THE REST OF THE PERIOD DUE TO A
SURFACE HIGH PRESSURE BUILDING OVER THE AREA TONIGHT/FRIDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1210 PM CDT Thu Sep 19 2013
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.UPDATE...
ISSUED AT 844 AM CDT THU SEP 19 2013
Scatted showers and even a few isolated thunderstorms will
continue across western and north central Kansas as an upper level
disturbance based the nam 450mb- 400mb pv lifts northeast across
western Kansas. HRRR appears to have a decent handle on this so
will lean in that direction for precipitation chances through the
early afternoon. Thunderstorms still appear become more widespread
across south central Kansas during the mid to late afternoon as a
cold front moves into south central Kansas, late day instability,
and the location of the left exit region of an upper level jet at
00z Friday. Also trended towards a non diurnal trend in
temperatures this afternoon behind the cold front as it crosses
western Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 212 AM CDT THU SEP 19 2013
Short range models indicate the upper level trough kicking out of
the Rockies into the Northern Plains today setting up shower and
thunderstorm chances across the Upper Midwest southwestward into the
Central Plains, including portions of central and western Kansas.
As the upper level trough moves into the Dakotas and Nebraska, an
attendant cold front will push southeastward into western Kansas
late this morning into the afternoon. Meanwhile, a +85kt upper level
jet is projected to climb northeast out of the desert southwest into
western and central Kansas from this afternoon into this evening.
Along with more favorable dynamic support aloft, steepening mid
level lapse rates and increased instability will be enough to
support thunderstorm development along and ahead of the cold front
as it begins to push further southeast into more favorable
moisture across central Kansas and eastern portions of southwest
Kansas. Although vertical shear profiles are not exactly ideal,
CAPE values in excess of 2000 J/KG ahead of the front will be
enough to support strong to marginally severe thunderstorms...mainly
southeast of a Hays to Liberal line. The potential for heavy
rainfall exists as well with NAM/GFS model soundings showing PW
values up around 1.5 inches.
Temperatures are expected to climb back up into the lower 90s(F)
across south central Kansas where the frontal passage isn`t likely
to occur until late this afternoon. Otherwise, look for highs up
into the upper 70s(F) and 80s(F) behind the front with the cooler
temperatures across west central Kansas. Lows generally down into
the 50s(F) are likely tonight as much cooler air filters south into
western Kansas overnight.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z nam bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 55 78 50 / 30 30 0 0
GCK 80 53 76 50 / 30 10 0 0
EHA 82 52 76 52 / 40 10 0 0
LBL 85 55 79 51 / 30 20 0 0
HYS 80 52 75 50 / 30 10 0 0
P28 92 60 80 52 / 80 80 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Burgert
SYNOPSIS...Burgert
SHORT TERM...JJohnson
LONG TERM...Gerard
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
921 AM MDT THU SEP 19 2013
.UPDATE...
ISSUED AT 909 AM MDT THU SEP 19 2013
AREA OF PRECIPITATION CONTINUES TO MARCH EAST AHEAD OF A COLD
FRONT THAT HAS MOVED THROUGH THE WEST HALF OF THE AREA SO FAR.
BEST CHANCES FOR RAINFALL CONTINUE TO LOOK TO BE OVER THE FAR EAST
AS LIFT FROM THE COLD FRONT COMBINED WITH AN UPPER LEVEL TROUGH
WILL MOVE THROUGH AROUND NOON. BEHIND THE FRONT NORTHERLY WINDS
HAVE BECOME GUSTY...RANGING FROM 20-30 MPH WITH SOME GUSTS NEARING
40 MPH IN FAR NORTHEAST COLORADO. THE GUSTS SHOULD START TO
DECLINE BY THE EARLY AFTERNOON AS THE SURFACE PRESSURE GRADIENT
BEHIND THE FRONT SLACKENS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE TAF PERIOD AT BOTH
TAF SITES. A SMALL SPREAD IN TEMPERATURE AND DEW POINT AT MCK
COULD LEAD TO MINOR REDUCTION OF VISIBILITY BRIEFLY THIS
MORNING...BUT NO VISIBILITY OR CEILING RESTRICTIONS ARE EXPECTED.
THERE IS SOME DISAGREEMENT IN MODEL GUIDANCE ON HOW EXTENSIVE
CLOUDS WILL BE THROUGH AFTERNOON. A BROKEN DECK IS A POSSIBILITY
BUT SHOULD REMAIN JUST ABOVE MVFR CRITERIA. WINDS WILL INCREASE THIS
AFTERNOON FROM THE NORTH AND VEER TO A NORTHEASTERLY DIRECTION BY
EVENING. GUSTS OVER 20 KNOTS ARE EXPECTED FROM LATE MORNING
THROUGH MID AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
857 AM CDT Thu Sep 19 2013
...Updated to precipitation chances today...
.SYNOPSIS...
ISSUED AT 1020 PM CDT WED SEP 18 2013
Water vapor imagery and upper air analysis indicate an upper level
trough of low pressure pushing eastward across the northern
Rockies of Montana and Wyoming. Near the surface, a lee side
trough of low pressure remains anchored across extreme eastern
Colorado. Surface dewpoints are in the upper 50s(F) to the lower
and mid 60s(F) across central and southwest Kansas.
&&
.UPDATE...
ISSUED AT 844 AM CDT THU SEP 19 2013
Scatted showers and even a few isolated thunderstorms will
continue across western and north central Kansas as an upper level
disturbance based the nam 450mb- 400mb pv lifts northeast across
western Kansas. HRRR appears to have a decent handle on this so
will lean in that direction for precipitation chances through the
early afternoon. Thunderstorms still appear become more widespread
across south central Kansas during the mid to late afternoon as a
cold front moves into south central Kansas, late day instability,
and the location of the left exit region of an upper level jet at
00z Friday. Also trended towards a non diurnal trend in
temperatures this afternoon behind the cold front as it crosses
western Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 212 AM CDT THU SEP 19 2013
Short range models indicate the upper level trough kicking out of
the Rockies into the Northern Plains today setting up shower and
thunderstorm chances across the Upper Midwest southwestward into the
Central Plains, including portions of central and western Kansas.
As the upper level trough moves into the Dakotas and Nebraska, an
attendant cold front will push southeastward into western Kansas
late this morning into the afternoon. Meanwhile, a +85kt upper level
jet is projected to climb northeast out of the desert southwest into
western and central Kansas from this afternoon into this evening.
Along with more favorable dynamic support aloft, steepening mid
level lapse rates and increased instability will be enough to
support thunderstorm development along and ahead of the cold front
as it begins to push further southeast into more favorable
moisture across central Kansas and eastern portions of southwest
Kansas. Although vertical shear profiles are not exactly ideal,
CAPE values in excess of 2000 J/KG ahead of the front will be
enough to support strong to marginally severe thunderstorms...mainly
southeast of a Hays to Liberal line. The potential for heavy
rainfall exists as well with NAM/GFS model soundings showing PW
values up around 1.5 inches.
Temperatures are expected to climb back up into the lower 90s(F)
across south central Kansas where the frontal passage isn`t likely
to occur until late this afternoon. Otherwise, look for highs up
into the upper 70s(F) and 80s(F) behind the front with the cooler
temperatures across west central Kansas. Lows generally down into
the 50s(F) are likely tonight as much cooler air filters south into
western Kansas overnight.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 649 AM CDT THU SEP 19 2013
Widely scattered thunderstorms will be possible across western and
central Kansas today as a cold front pushes south across the
western part of the state. Will carry VCTS at the taf sites
through much of the day. Depending on thunderstorm trends,
thunderstorms may need to be added to tempo or prevailing groups
this afternoon. Southwesterly winds will become westerly ahead of
the front this morning before switching to the north to northeast
behind the front this afternoon. Showers and thunderstorms will be
moving out of the region by this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 55 78 50 / 30 30 0 0
GCK 80 53 76 50 / 30 10 0 0
EHA 82 52 76 52 / 40 10 0 0
LBL 85 55 79 51 / 30 20 0 0
HYS 80 52 75 50 / 40 10 0 0
P28 92 60 80 52 / 80 80 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Burgert
SYNOPSIS...JJohnson
SHORT TERM...JJohnson
LONG TERM...Gerard
AVIATION...Gerard
AREA FORECAST DISCUSSION
NWS GOODLAND KS
545 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE TAF PERIOD AT BOTH
TAF SITES. A SMALL SPREAD IN TEMPERATURE AND DEW POINT AT MCK
COULD LEAD TO MINOR REDUCTION OF VISIBILITY BRIEFLY THIS
MORNING...BUT NO VISIBILITY OR CEILING RESTRICTIONS ARE EXPECTED.
THERE IS SOME DISAGREEMENT IN MODEL GUIDANCE ON HOW EXTENSIVE
CLOUDS WILL BE THROUGH AFTERNOON. A BROKEN DECK IS A POSSIBILITY
BUT SHOULD REMAIN JUST ABOVE MVFR CRITERIA. WINDS WILL INCREASE THIS
AFTERNOON FROM THE NORTH AND VEER TO A NORTHEASTERLY DIRECTION BY
EVENING. GUSTS OVER 20 KNOTS ARE EXPECTED FROM LATE MORNING
THROUGH MID AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1154 PM MDT WED SEP 18 2013
A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE PRE-FRONTAL TROUGH
MOVING ACROSS THE CENTRAL HIGH PLAINS REGION TONIGHT. A FEW STORMS
ARE MOVING NORTHEASTWARD IN THE VICINITY OF MCK AND GLD AND ARE
EXPECTED TO BE PRESENT THROUGH ABOUT 09Z. AFTER 09Z...STORMS ARE
EXPECTED TO DIMINISH AND MOVE OUT OF THE REGION. VFR CONDITIONS
ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD AT BOTH MCK AND GLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM..BRB
LONG TERM...BULLER
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS PADUCAH KY
845 PM CDT Fri Sep 20 2013
.UPDATE...
A tight sfc wave (shown especially in NAM12 data) was moving newd
through the srn Pennyrile region of wrn ky this evening, offering a
potential source of lift. To the nw of this feature, light sfc winds
had already turned to the north ahead of a cold front moving through
the nwrn half of the PAH forecast area. Working against the feature
is the stabilizing atmosphere. What is left of any lower trop
instability will quickly exit the ern fringes of the region shortly.
Thus, there is no mention of tstms or locally heavy rain in the
forecast beyond 03z. The forward progress of the front seemed to be
on track at this time, and all pcpn should be out of the region by
12z.
&&
.SHORT TERM /Tonight through Sunday night/...
ISSUED AT 240 PM CDT FRI SEP 20 2013
Forecast seems to be panning out fairly well. Widespread rain has
overspread most of the forecast area this afternoon. Aside from a
convective cluster over western Kentucky...deep convection has been
largely absent. Instability has been limited by lack of solar
heating due to thickening mid/high clouds.
The qpf forecast seems to be on track...with the lowest amounts in
southern IL and southeast MO. Heavy rainfall is still occurring and
expected in western KY and possibly southwest IN. Due to dry
ground...any issues should be limited to urban and poor drainage
areas. Rainfall rates will continue to be locally over one inch per
hour in convection.
The latest HRRR is fairly close to the model consensus. The back
edge of the rain will move across the kpah/kevv areas in the 03z to
06z time frame. The precip will end in the khop area by 12z.
Clearing will occur on Saturday morning...with nothing more than
some scattered cu in the afternoon. 850 mb temps are forecast to
fall to around 10...which supports mos guidance highs in the mid
70s.
Little change in 850 mb temps or moisture profiles is forecast
through Sunday night. This will keep clear and cool conditions in
place...with daytime highs in the 70s and overnight lows in the mid
40s to near 50. North to northeast low level winds will slowly
decrease as high pressure builds overhead.
.LONG TERM /Monday through Friday/...
ISSUED AT 240 PM CDT FRI SEP 20 2013
As we head into next week, it now appears as though the upper level
high over the eastern U.S. will shift farther east as short wave
energy moves east into the MS River Valley. It still appears as
though our region may stay in between the two main branches of
energy, one passing to our north and the other just to our
south/east. If current trends continue, later forecasts may need to
mention a chc of rain in srn portions of west KY on Tuesday/Tue
night.
Thereafter...the upper high over the southeast U.S. will begin to
flex its muscle, and build north into the Ohio Valley. Thus... we
should see less cloud cover and warming temps as we head into the
Wed/Thu/Fri time frame. Most locations will likely be back into the
middle 80s by Wednesday afternoon. Humidity levels should stay
fairly comfortable until late in the week, when southerly flow will
develop ahead of an approaching cold front.
&&
.AVIATION...
ISSUED AT 1237 PM CDT FRI SEP 20 2013
Cold front pushing into the region 22z-02z, turning winds from
west to north around 10 kts after the passage. Expect numerous
showers and MVFR vsbys/cigs ahead of the front. Cannot rule out
isolated thunder along and south of the OH River until the front
passes. May also be a period of IFR/Low IFR behind the front in
light rain or DZ. Skies should finally clear 08-12z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DB
SHORT TERM...MY
LONG TERM...GM
AVIATION...GM
AREA FORECAST DISCUSSION
NWS JACKSON KY
217 AM EDT THU SEP 19 2013
.UPDATE...
ISSUED AT 217 AM EDT THU SEP 19 2013
HAVE SENT A MINOR UPDATE INCORPORATING RECENT OBSERVATIONS.
UPDATE ISSUED AT 1030 PM EDT WED SEP 18 2013
FRESHENED UP THE SKY COVER AND HOURLY TEMPERATURES AND DEW POINTS TO
ACCOUNT FOR THE LATEST TRENDS. SOME PARTIAL CLEARING WILL WORK IN
FROM THE WEST...HOWEVER BELIEVE THAT LOW CLOUDS WILL FILL BACK IN
DURING THE OVERNIGHT WITH HIGH MOISTURE IN THE 1000-850 MB LAYER
LINGERING. LEFT THE POPS AS IS...ALTHOUGH THE LATEST HRRR HAS BACKED
OFF ON THE UPTICK IN CONVECTION TOWARDS DAWN FOR THE NORTHEASTERN
PORTION OF THE AREA.
UPDATE ISSUED AT 807 PM EDT WED SEP 18 2013
A FEW SHOWERS WILL WIND DOWN ACROSS NORTHEASTERN KENTUCKY IN THE NEXT
HOUR. THE LATEST SHORT RANGE MODELS SHOW A LULL IN THE ACTIVITY
THROUGH THE OVERNIGHT...BEFORE AN UPTICK OCCURS TOWARDS DAWN IN THE
NORTHEASTERN HALF OF THE AREA...AS A WEAK SHORT WAVE TROUGH MOVES
SOUTHEAST ACROSS OHIO VALLEY. HAVE BUMPED UP THE POPS A BIT
CONSIDERING THE DECENT MODEL AGREEMENT. ALSO ADDED SOME PATCHY FOG
AND MADE THE VALLEY TEMPERATURES A BIT MORE UNIFORM WITH ALL OF THE
CLOUD COVER AND STEADY DEW POINTS IN THE LOW 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 307 PM EDT WED SEP 18 2013
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE MAJOR UPPER AIR
FEATURES...HOWEVER THERE IS QUITE A BIT OF DIFFERENCE IN HOW THEY
HANDLE THE PRECIPITATION FORECASTS OVER THE NEXT 36 HOURS. A WARM
FRONT HAS MOVED TO THE NORTHEAST OF THE AREA AND EASTERN KENTUCKY IS
NOW IN THE WARM SECTOR WITH A SURFACE HIGH OFF THE EAST COAST AND A
SURFACE RIDGE EXTENDING ACROSS EASTERN KENTUCKY. A COLD FRONT IS OVER
THE HEARTLAND AND WILL BE APPROACHING THE AREA...HOWEVER WILL NOT
MOVE INTO EASTERN KENTUCKY UNTIL SATURDAY. THIS ALLOWS FOR THE GULF
TO BE OPENED UP AND THERE WILL BE SOME FAIRLY WARM...MOIST AND
CONDITIONALLY UNSTABLE AIR OVER THE AREA. THE MODELS DIFFER AS TO
WHEN WEAK LITTLE PERTURBATIONS WILL BE ABLE TO KICK OFF ANY
CONVECTIVE ACTIVITY. FROM EXPERIENCE...EXPECT THAT THERE WILL BE AN
AFTERNOON AND EVENING MAXIMUM OF CONVECTIVE ACTIVITY...HOWEVER THERE
MAY BE SOME UNEXPECTED LITTLE POP-UPS DURING THE OFF HOURS. THE MODEL
BLEND HANDLED THE TEMPERATURES VERY WELL AND JUST MADE SOME MINOR
TWEAKS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 PM EDT WED SEP 18 2013
ON FRIDAY A COLD FRONT EXTENDING FROM THE WESTERN GREAT LAKES INTO
THE MID MS VALLEY WILL BE MOVING EAST AS AN UPPER LEVEL SHORT WAVE
TROUGH PUSHES EAST THROUGH THE PLAINS. THE UPPER TROUGH AND SURFACE
COLD FRONT WILL MOVE EAST WITH RAIN CHANCES INCREASING ACROSS THE
AREA AS WE HEAD INTO THE WEEKEND. MOST RECENT RUNS OF THE VARIOUS
OPERATIONAL MODELS ARE POINTING TOWARDS SLOW FRONTAL MOVEMENT WITH
THE FRONT MOVING ACROSS THE AREA ON SATURDAY...AND LIKELY STALLING
OUT. THE LATEST WPC GUIDANCE IS ALSO FAVORING THIS IDEA WITH THE
FRONT APPROACHING THE FORECAST AREA AT 12Z SATURDAY. OF THE
OPERATIONAL MODELS THE 12Z NAM IS THE OUTLIER...AS IT PUSHES THE
UPPER TROUGH AND SURFACE FRONT THROUGH MUCH QUICKER...WITH THE FRONT
EAST OF KY BY 15Z SATURDAY. WILL LEAN AWAY FROM THE NAM FORECAST AS
ALL THE OTHER MODELS ARE MUCH SLOWER. THE 12Z GFS SHOWS THE SOUTHERN
PART OF THE UPPER TROF SLOWING DOWN WITH AN UPPER LOW CLOSING OFF IN
THE VICINITY OF EASTERN KY BY SUNDAY. THE 00Z ECMWF AND 12Z GEM ALSO
SUPPORT THE IDEA OF SLOW MOVEMENT WITH AN UPPER LOW FORMING OVER THE
UPPER SOUTH INTO THE TN VALLEY. OVERALL...MODELS AND WPC GUIDANCE
POINT TOWARDS WET CONDITIONS OVER THE WEEKEND. THE LATEST BLENDED
LOAD ALSO SUPPORTS THIS. EXACTLY HOW LONG THE SLOW MOVING UPPER LOW
AND ASSOCIATED SURFACE LOW LINGER NEARBY AND CONTINUE TO AFFECT
OUR WEATHER IS STILL UNCERTAIN. THE 00Z ECMWF POINTS TOWARDS RAIN
CHANCES LINGERING INTO THE MIDDLE OF NEXT WEEK...WHILE THE 12Z GFS
IS DRIER...WITH LESS OF A CHANCE OF RAIN AFTER MONDAY. WHILE THE
STANDARD BLENDED LOAD RESULTED IN A CHANCE OF RAIN IN THE SOUTHEAST
ON TUESDAY AND WEDNESDAY HAVE DECIDED TO FOLLOW THE CONSENSUS OF
NEIGHBORING WFOS AND WILL GO WITH A DRY FORECAST ON TUESDAY AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 217 AM EDT THU SEP 19 2013
CONDITIONS STARTED OUT MOSTLY VFR. HOWEVER...DETERIORATION IS
EXPECTED OVERNIGHT. IFR IS FORECAST FOR MOST LOCATIONS DUE TO LIGHT
FOG. HOWEVER...CONFIDENCE IS LOW CONCERNING HOW FAR THE VISIBILITY
DROPS. FOG WILL DISSIPATE ON THURSDAY MORNING...BUT MVFR CEILINGS ARE
EXPECTED TO PERSIST IN MOST AREA UNTIL EARLY AFTERNOON...BEFORE
SCATTERING OUT AND LEAVING VFR TO FINISH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JJ
LONG TERM...SBH
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1153 PM CDT Wed Sep 18 2013
.UPDATE...
ISSUED AT 1153 PM CDT WED SEP 18 2013
The aviation section has been updated for the 06Z TAF issuance.
&&
.SHORT TERM /Tonight through Friday night/...
ISSUED AT 230 PM CDT WED SEP 18 2013
The showers and isolated thunderstorms that occurred this morning
have all but dissipated by mid afternoon. Partial clearing will
continue to spread slowly east. The trend toward low and mid level
drying is indicated by RAP and nam model soundings. This drying
appears to be in response to a gradual rebuilding of the 500 mb
ridge that was flattened by a weak impulse this morning.
Through Thursday...the mid level ridge will continue to slowly build
over our region. This should continue to suppress most convection
over the Lower Ohio and Mid Mississippi Valleys. Will keep slight
chance pops during the peak heating hours from roughly 18z to 00z to
account for isolated diurnally driven storms.
A rather strong cold front will approach from the northwest on
Thursday night...reaching southern Illinois and southeast Missouri
on Friday. The front will continue moving southeast across western
Kentucky and southwest Indiana on Friday evening. The 09z sref
timing looks reasonable. A deepening upper trough will enhance lift
along the frontal zone...and deep layer moisture will be high for
this time of year /sref precip water values about 1.9 inches/. Looks
like the first widespread significant rainfall of the month will
occur. Storm total qpf should be at least one half inch...with some
1 inch amounts likely in heavier convection. Severe weather
potential will depend on how much sunshine and diurnal heating takes
place ahead of the front. Isolated severe convection is currently
forecast by SPC /see day 3 outlook/.
South to southwest low level flow will keep unseasonably warm and
humid conditions in place through Friday. The nam continues to have
problems with too much moisture in the model...as shown in its high
pops and abundant cloudiness. The warmer gfs mos highs look better
for Thursday.
.LONG TERM /Saturday through Wednesday/...
ISSUED AT 230 PM CDT WED SEP 18 2013
Main issue in the extended looks to be with how quickly an upper
level trof will move east out of the region over the weekend. Models
seem to be trending toward a less progressive solution in this
respect. Both the operational GFS and ECMWF suggest showers will
linger into Saturday along and south of the Ohio River, east of
the H50 trof axis. Will bump up precip chances on Sat into the 40
to 50 percent range over much of the Pennyrile region of western
KY.
Otherwise, the most noticeable change over the weekend will be
another transition to much cooler and less humid conditions. Highs
both Saturday and Sunday will likely stay down in the 70s, with lows
Sat night mostly in the 50 to 55 degree range.
As we head into next week, it now appears as though an Omega
Blocking pattern will become established along the MS River Valley.
This should keep things quite dry across our region, with sunny,
warm afternoons and cool nights. Temperatures will warm a touch each
day, and most locations will likely be back into the middle 80s by
Wednesday afternoon. Humidity levels should stay low though.
&&
.AVIATION...
ISSUED AT 1153 PM CDT WED SEP 18 2013
Some mid-level ceilings and light showers over central Illinois
may try to clip KEVV late tonight. Elected not to mention any
precipitation as it would likely be of little impact. Still
looking at 5kts of a south wind overnight at all sites, so will
not mention fog. The only issue may be at KOWB where they are
nearly saturated as of 04Z.
Added in a minor SSW gust in most locations for Thursday, due to
a decent pressure gradient and decent mixing expected. Still
cannot rule out some isolated to scattered diurnal convection, but
will not mention anything in the forecast at this time. Even if
there is development, the coverage would likely be too sparse to
mention.
Light south winds and mid clouds can be expected throughout the
area Thursday evening.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MY
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
328 PM EDT THU SEP 19 2013
.SYNOPSIS...
ALTHOUGH SHOWERS ARE POSSIBLE THROUGH FRIDAY...WIDESPREAD RAIN IS
NOT EXPECTED TO FALL UNTIL FRIDAY NIGHT AND SATURDAY WITH THE
ARRIVAL OF A STRONG COLD FRONT.
&&
.NEAR TERM /THROUGH FRIDAY/...
STARTING TO LOOK AS IF PRECIPITATION WILL JUST NOT GET STARTED THIS
AFTERNOON. SHOWERS HAVE MANAGED TO STAY ACROSS CENTRAL OHIO AND
WESTERN WEST VIRGINIA...NOT ENTERING OUR FORECAST AREA. RAP MODEL
SHOWS A VERY SMALL SHORTWAVE OVER OHIO DISSIPATING AS IT MOVES TO
THE SOUTHEAST THIS AFTERNOON...AND EXCEPT FOR THE FAR WESTERN OHIO
COUNTIES...CONDITIONS SHOULD REMAIN DRY WELL PAST MIDNIGHT. COULD
START TO SEE SOME CONVECTION OVERNIGHT...BUT REALLY THINK THAT
DIURNAL TIMING SHOULD STILL PUSH MOST PRECIPITATION UNTIL FRIDAY
AFTERNOON. HIGH-RESOLUTION MODELS ARE SHOWING VERY LITTLE
PRECIPITATION AHEAD OF THE COLD FRONT EVEN DURING THE AFTERNOON. SPC
CONVECTIVE OUTLOOK SHOWS A POSSIBILITY FOR A STRONG TO SEVERE STORM
FRIDAY...BUT BOTH INSTABILITY AND WIND SHEAR SHOULD REMAIN MARGINAL.
EVEN WITHOUT PRECIPITATION...THINK THAT MOIST LOW LEVELS COULD ALLOW
FOR ANOTHER ROUND OF LOW CLOUDS TO DEVELOP AFTER MIDNIGHT AND
PERSIST INTO THE MORNING HOURS. THIS WOULD SQUASH MUCH OF THE
DIURNAL TEMPERATURE CURVE...ALLOWING FOR ABOVE NORMAL LOW
TEMPERATURES...WITH HIGHS REACHING INTO THE UPPER 70S WITH MOSTLY
HIGH CLOUDS TOMORROW.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
MODEL SOLUTIONS CONTINUE TO GENERALLY VARY LESS THAN 6 HOURS WITH
THE TIMING OF THE FRONTAL PROGRESSION ACROSS THE AREA ON SATURDAY.
IN GENERAL...MODELS FAVOR A PASSAGE IN OHIO IN THE MORNING...AND
PENNSYLVANIA/WEST VIRGINIA IN THE AFTERNOON. THE FORECAST WAS
ADJUSTED A BIT TOWARD THE SLOWER END OF THE GUIDANCE OWING TO A
SECONDARY VORT MAXIMA DIGGING INTO THE BASE OF THE MID-LEVEL
TROUGH SUPPORTING THE FRONTAL PROGRESSION. WITH THIS TYPE OF
DEVELOPMENT...A SLOWER SOLUTION GENERALLY VERIFIES.
ADDITIONALLY...THE 12Z GFS/ECMWF/CANADIAN ALL CAME IN A TAD SLOWER
THAN THE NAM AND THEIR PREVIOUS CYCLE COUNTERPARTS...SO HANGING
ONTO HIGHER POPS INTO THE AFTERNOON STILL SEEMS PRUDENT.
CONVECTIVE DEVELOPMENT ALONG THE FRONT STILL SEEMS RATHER
UNLIKELY. UPPER JET STREAK COUPLING...WHILE STRONG OVER INDIANA
FRIDAY EVENING AND NIGHT...QUICK BECOMES LESS IMPRESSIVE ON
SATURDAY AS THE SECONDARY VORT DIGS INTO THE TROUGH. AS THIS
OCCURS...THE NORTHER JET STREAK QUICKLY BECOMES DISASSOCIATED FROM
THE SOUTHERN JET STREAK BY SATURDAY AFTERNOON. AS A
CONSEQUENCE...UPPER FORCING FADES A BIT AS THE FRONT PROGRESSES
ACROSS THE AREA. ADDITIONALLY...SIGNIFICANT ADVANCE CLOUD COVER
SHOULD PRECLUDE SIGNIFICANT INSTABILITY GENERATION.
FURTHERMORE...WITH THE DISSOCIATION OF THE LARGE SCALE FLOW IN THE
MID AND UPPER LEVELS...SHEAR VALUES ACTUALLY DECREASE IN OUR
SECTOR OF THE FRONT THROUGH THE DAY SATURDAY. AS SUCH...WITH
LITTLE INSTABILITY AND WEAKENING SHEAR...THUNDERSTORM CHANCES DO
NOT SEEM LIKELY WITH FADING UPPER LEVEL SUPPORT. HOWEVER...WHILE
NOT LIKELY...LOW LEVEL CONVERGENCE ALONG THE FRONT AND SOME AMOUNT
OF FRONTOGENETICAL FORCING MAY GIVE ENOUGH OF A KICK TO WORK WITH
THE ROUGHLY 300 J/KG OF 1000-700 MB MUCAPE IMMEDIATELY ALONG THE
FRONT. TO COVER THIS...SLIGHT CHANCES OF THUNDER WERE CARRIED
BASICALLY RIGHT WITH THE FRONTAL PASSAGE.
WHILE THUNDER DOES NOT SEEM PARTICULARLY LIKELY...MODEL TIME HEIGHT
SECTIONS DO INDICATE NEGATIVE THETA-E LAPSE RATES THROUGH THE
DEEPLY SATURATED LAYER IN THE 5-10 KFT LAYER...WHICH IS ALL WARMER
THAN 0C. SHALLOW CONVECTION WITH LOW CENTROID ECHOES AND DECENT
INSTABILITY IN THE STRONGLY SATURATED LAYER COUPLED WITH PWATS UP
TOWARD 1.7 INCHES SHOULD ALLOW FOR A PERIOD OF FAIRLY HEAVY
RAINFALL ALONG THE FRONT. AS SUCH...QPF VALUES COULD PUSH AN INCH
ACROSS THE AREA DUE TO A BIT SLOWER FRONTAL PROGRESSION.
THE FRONT EXITS TO THE EAST SATURDAY NIGHT. MUCH COLDER AIR FLOODS
INTO THE REGION AS CONSENSUS 850 MB TEMPERATURES FALL TOWARD +2 TO
+4C. SOME STRATOCUMULUS GENERATION IS LIKELY OFF LAKE ERIE IN
NORTHWESTERLY FLOW THROUGH SUNDAY...WHICH SHOULD HOLD TEMPERATURES
BACK QUITE A BIT BELOW NORMAL. FRIES
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
STRONG SHORTWAVE TROUGH WILL CROSS THE AREA LATE SAT/SAT NIGHT
WITH THE CAA. COULD SEE SOME ADDITIONAL SHOWERS DEVELOP WITH THIS
FEATURE.
STRONG SURFACE HIGH WILL MOVE THROUGH THE GREAT LAKES FOR THE
REMAINDER OF THE LONG TERM.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
CLOUDS HAVE BEEN SLOW TO LIFT TODAY...BUT THINK THAT ALL LOCATIONS
SHOULD EVENTUALLY REACH VFR BY SUNSET. MODELS ARE INDICATING THAT
WITH MOIST LOW LEVELS...ANOTHER ROUND OF LOW MVFR/IFR CIGS ARE
POSSIBLE OVERNIGHT INTO FRIDAY MORNING. CONSIDERING MODEL GUIDANCE
PICKED UP ON THIS LAST NIGHT...WILL TRUST THE GUIDANCE A BIT MORE
WITH THE LOW CIG FORECAST TONIGHT. WITH WINDS A BIT STRONGER FRIDAY
MORNING COMPARED TO THIS MORNING...THINK CLOUDS WILL SCATTER OUT BY
MID MORNING...WITH GENERALLY HIGH CLOUDS AHEAD OF THE ADVANCING COLD
FRONT. WIDESPREAD PRECIPITATION IS EXPECTED TO STAY WEST OF ZZV BY
18Z AND PIT BY 00Z SATURDAY.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED FRI NGT THROUGH SAT NGT AS
RAIN DVLPS WITH A CROSSING CDFNT. HIGH PRESSURE SHOULD THEN KEEP
CONDITIONS VFR SUNDAY THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
409 PM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 407 PM EDT THU SEP 19 2013
IT WILL BE WARM AND HUMID ACROSS NORTHERN MICHIGAN THROUGH
FRIDAY...AHEAD OF A STRONG COLD FRONT PUSHING ACROSS THE WESTERN
LAKES. THIS BOUNDARY WILL GENERATE SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS THROUGH FRIDAY...BEFORE SEASONAL CONDITIONS AND SOME
LAKE INDUCED RAINS RETURN TO NORTHERN MICHIGAN TO START THE WEEKEND.
HIGH PRESSURE WILL SETTLE INTO THE REGION SUNDAY AND MONDAY. THIS
PATTERN WILL GENERATE AN EXTENDED STRETCH OF DRY AND COMFORTABLE
WEATHER ACROSS THE GREAT LAKES FOR THE FIRST OFFICIAL WEEK OF FALL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 407 PM EDT THU SEP 19 2013
WARM...AND AN APPRECIABLY MUGGY AIRMASS...HAS OVERSPREAD THE NORTH
WOODS THIS AFTERNOON. DESPITE THIS...LOSS OF ANY DYNAMICS HAS LED
TO A DRY LATE MORNING AND EARLY AFTERNOON...WITH FOCUS FOR RAINS
SHIFTING WELL TO OUR SOUTH AND WEST. FORMER TIED TO REMNANT COLD
POOL AND LOW LEVEL JET DYNAMICS...WITH THE LATTER FOCUSED ALONG AND
AHEAD OF STRONG SHORTWAVE TROUGH AND ATTENDANT COLD FRONT SUPPORT.
THIS UPSTREAM SYSTEM WILL BE THE IMPETUS FOR ADDITIONAL SHOWERS AND
STORMS HEADING INTO TONIGHT AND FRIDAY. FORECAST CHALLENGES CENTER
ON THESE RAIN POSSIBILITIES.
TOUGH CALL FOR THE REMAINDER OF THIS AFTERNOON INTO EARLY THIS
EVENING. APPEARS FOCUS FOR ANY RAINS WILL BE CENTERED ON LOW LEVEL
CONVERGENCE AXES AND DEVELOPMENT OF SURFACE INSTABILITY. NOTED
CONVERGENCE AXIS DRIFTING SLOWLY NORTH ACROSS THE HIGHLANDS AS OF
THIS WRITING...WELL EVIDENT ON LOCAL RADAR IMAGERY. PER SPS SURFACE
ANALYSIS...BULLSEYE OF 1.5K TO 2.0K ML CAPE HAS DEVELOPED OVER
INTERIOR NORTHERN LOWER MICHIGAN. STILL EVIDENCE OF SOME WEAKISH
CINH TO OVERCOME. REALLY NOT SURE HOW THIS WILL ALL PLAY OUT...BUT
FEEL ABOVE DEFINITELY WORTHY OF KEEPING SOME SHOWER AND STORM
MENTION HEADING INTO EARLY THIS EVENING. FOR WHAT IT`S
WORTH...LATEST RAP SHOWS GOOD STORM DEVELOPMENT HEADING INTO THIS
PERIOD...FOCUSED ACROSS THE INTERIOR HIGHLANDS. RELATIVELY HIGH
PWATS SUPPORT LOCALLY HEAVY RAINS IF/WHERE CONVECTION DEVELOPS.
FOCUS WILL SHIFT TO LOW LEVEL JET DYNAMICS AND APPROACH OF COLD
FRONT FOR SHOWER AND STORM POTENTIAL HEADING INTO TONIGHT. RECENT
TRENDS AND PATTERN RECOGNITION SUPPORT BEST FORCED LOW LEVEL MASS
CONVERGENCE FOCUSED ALONG THE LAKE MICHIGAN CORRIDOR OF NORTHWEST
LOWER AND EASTERN UPPER MICHIGAN AFTER 05Z. MOISTURE REMAINS
GREAT...AND SIMPLE MAGNITUDE OF CONVERGENCE SHOULD BE ENOUGH TO
DRIVE ADDITIONAL ACTIVITY. WILL FOCUS BEST POTENTIAL IN THESE
AREAS...TAPERING TO JUST CHANCY WORDING ACROSS NORTHEAST LOWER
MICHIGAN. ELEVATED NATURE OF STORMS SHOULD PRECLUDE MUCH SEVERE
POTENTIAL. ONCE AGAIN... HOWEVER...GOOD MOISTURE PROFILES SUPPORT
LOCALLY HEAVY RAIN CONCERNS.
SURFACE FRONT LOOKS TO REMAIN AGGRESSIVE HEADING INTO FRIDAY...WITH
LATEST GFS/ECMWF TRENDS DRIVING THE FRONT INTO LAKE HURON THROUGH
EARLY AFTERNOON. PRE-FRONTAL SHOWERS AND STORMS SHOULD
CONTINUE...WITH STRONG UPPER JET SUPPORT AND FGEN DYNAMICS DRIVING
POST-FRONTAL RAINS IMMEDIATELY BEHIND THE SURFACE PORTION OF THE
FRONT. INHERITED GRIDS WELL TRENDED THIS DIRECTION WITH NO
SIGNIFICANT CHANGES NEEDED. DESPITE DECENT KINEMATICS...PLENTY OF
CLOUD COVER AND FASTER TIMING OF FRONT LOOKS TO KEEP SURFACE BASED
INSTABILITY IN CHECK...ONCE AGAIN PRECLUDING MUCH SEVERE WEATHER
POTENTIAL. LATEST SPC GRAPHICS CONCUR...KEEPING SLIGHT CHANCE
WORDING JUST TO OUR SOUTHEAST.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 407 PM EDT THU SEP 19 2013
OVERVIEW AND TRENDS: SUBSTANTIAL LONG WAVE TROUGHING IN PLACE THIS
MORNING FROM THE GULF OF ALASKA DOWN ALONG THE WEST COAST...WITH
DOWNSTREAM RIDGING/WARM AIR ACROSS THE CENTRAL CONUS INTO THE GREAT
LAKES...AND TROUGHING FROM GREENLAND DOWN THROUGH EASTERN CANADA.
LONG WAVE RIDGING IS STILL SLATED TO SLOWLY ADVANCE INTO THE EASTERN
CONUS THROUGH THE WEEKEND...WHILE LARGER SCALE FLOW FLATTENS AND
CONTRACTS TOWARD THE POLE AS WE GO THROUGH NEXT WEEK. SO...NO LONG
LASTING TRANSITION TOWARD COOL FALL WEATHER JUST YET.
ON THE SMALLER SCALE...A COUPLE OF STRONGER SHORT WAVES EMBEDDED
WITHIN THE LARGER SCALE FLOW...ONE PUSHING INTO THE NRN PLAINS THAT
WILL IMPACT US OVER THE NEXT FEW DAYS...AND ANOTHER STRONG WAVE JUST
OFF THE PACIFIC NW COAST THAT WILL PUSH INTO THE PAC NW LATER THIS
WEEKEND. CLOSER TO HOME...LOW PRESSURE STRETCHES FROM SOUTH-CENTRAL
CANADA INTO THE NRN PLAINS...AHEAD OF THE AFOREMENTIONED SHORT WAVE.
ASSOCIATED WARM FRONT STRETCHES DOWN THROUGH THE MIDWEST AND
TRAILING COLD FRONT FROM MINNESOTA INTO THE CENTRAL PLAINS. HAVE
DEALT WITH A COUPLE OF ROUNDS OF SHOWERS AND STORMS WORKING THROUGH
THE REGION ALONG ADVANCING LOW LEVEL MOISTURE AXIS PUSHING INTO THE
REGION NORTH OF THE WARM FRONT.
LATE FRIDAY AFTERNOON THROUGH SATURDAY...SHORT WAVE/THERMAL TROUGH
AXIS ADVANCES INTO THE GREAT LAKES OVERNIGHT THROUGH SATURDAY
MORNING. FROPA TIMING AMONG MODEL SOLUTIONS STILL IN GOOD
AGREEMENT...KICKING THE FRONT EASTWARD INTO LAKE HURON BY EARLY
FRIDAY EVENING. CONSENSUS AMONG MODEL QPF ALSO SUGGESTS MOST...IF
NOT ALL...SYNOPTIC PRECIP WILL END BY EARLY EVENING...SAVE FOR JUST
A SMALL SLIVER OF THE E/SE COUNTIES. HOWEVER...GIVEN THE STRONG S-N
ORIENTED UPPER JET CORE ALONG THE BASE OF THE INCOMING TROUGH THAT
SLIDES ACROSS THE CWA RIGHT BEHIND THE FRONT...AM STILL CONCERNED
THAT POST FRONTAL/JET FORCED RAINFALL LINGERS JUST A BIT LONGER INTO
THE EARLY TO MID EVENING HOURS THAN MODEL QPF SUGGESTS. WITH THAT IN
MIND...HAVE SLOWED PRECIP ENDING JUST A BIT LATE FRIDAY AFTERNOON
AND EARLY EVENING. PROBABLY THE PATH OF LEAST REGRET AT THIS POINT
GIVEN ALL THE FRIDAY EVENING ACTIVITIES. REGARDLESS...LOW LEVEL
COOL/MOIST AIR OVERSPREADING THE REGION FRIDAY EVENING (AND SOME
SEMBLANCE OF A WEAK LOW LEVEL TROUGH) MAY LEAD TO STRATUS AND
PERHAPS SOME PATCHY DRIZZLE FRIDAY EVENING. THEN...SUBSIDENCE AND
STRONG COLD ADVECTION CONTINUE THROUGH THE REST OF FRIDAY NIGHT AND
THROUGH THE DAY SATURDAY WITH H8 TEMPS DIPPING TO A FEW DEGREES
ABOVE 0C BY SATURDAY MORNING...AND DOWN AROUND 0C DURING THE DAY
SATURDAY. PLENTY ENOUGH COOL AIR/LAKE INSTABILITY AND SYNOPTIC
MOISTURE ALONG THE BACKSIDE OF THE DEPARTING LOW FOR LAKE
EFFECT/INDUCED RAIN SHOWERS OVERNIGHT FRIDAY NIGHT THROUGH A GOOD
PART OF SATURDAY. SO ANOTHER COOL-ISH SATURDAY LOOKS ON TAP WITH
MAINLY CLOUDY SKIES...SCATTERED RAIN SHOWERS AND SOME GUSTIER NW
WINDS.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...IMPROVEMENT SATURDAY NIGHT AND
ESPECIALLY SUNDAY AS LARGE EXPANSE OF HIGH PRESSURE BUILDS OVER THE
REGION AND SUBSTANTIALLY DRIER AIR BUILDS OVERHEAD. COOLEST NIGHTS
OF FORECAST WILL OCCUR BOTH SATURDAY NIGHT AND SUNDAY NIGHT AS
CLEARING SKIES/WEAKENING WINDS SET THE STAGE FOR GOOD RADIATIONAL
COOLING. A GOOD DEAL OF SUNSHINE FOR SUNDAY WITH TEMPERATURES
REBOUNDING JUST A BIT TO THE MIDDLE 50S TO LOWER 60S.
MONDAY THROUGH THURSDAY...LARGE EXPANSE OF HIGH PRESSURE WILL REMAIN
THE DOMINANT WEATHER FEATURE ACROSS THE GREAT LAKES AND ACROSS
EASTERN CANADA THROUGH MUCH OF NEXT WEEK...WITH FAIR WEATHER
ANTICIPATED TO KICK OFF THE FIRST OFFICIAL WEEK OF FALL. GRADUAL
WARMING TREND THROUGH MIDWEEK AS TEMPERATURES REBOUND BACK TO AROUND
NORMAL READINGS FOR MID-LATE SEPTEMBER. GFS SOLUTION HAS ENOUGH
WARM/MOIST ADVECTION INTO THE UPPER MIDWEST/WESTERN GREAT LAKES TO
CONSIDER SOME CHANCES FOR SHOWERS BY THURSDAY. ECMWF IS NOWHERE
CLOSE WITH HIGH PRESSURE REMAINING DOMINANT. WILL FOLLOW THE DRY
ECMWF FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 135 PM EDT THU SEP 19 2013
SHOWERS AND STORMS WILL LIKELY BE ON THE INCREASE ONCE AGAIN
HEADING THROUGH TONIGHT AND INTO FRIDAY AS A STRONG COLD FRONT
MOVES THROUGH THE REGION. WILL INTRODUCE MVFR CONDITIONS WITH
PASSAGE OF BETTER SHOWERS AND MOST AGGRESSIVE DYNAMICS. SOME
CONCERN FOR IFR CIGS DEVELOPING IN AND JUST BEHIND THE PRIMARY
RAIN SHIELD HEADING INTO FRIDAY MORNING. CONFIDENCE JUST NOT THERE
TO INCLUDE AT THIS TIME. LOW LEVEL JET WILL LEAD TO WIND SHEAR
OVER THE WESTERN TAF SITES TONIGHT.
&&
.MARINE...
ISSUED AT 407 PM EDT THU SEP 19 2013
GUSTY SOUTH WINDS WILL CONTINUE TONIGHT...ESPECIALLY ACROSS
LAKE MICHIGAN...AS A STRONG COLD FRONT APPROACHES THE NORTHERN
LAKES. CURRENT TRENDS SUPPORT CONDITIONS REMAINING JUST BELOW SCA
CRITERIA. SHOWERS AND STORMS EXPECTED TO REDEVELOP THIS EVENING AND
OVERNIGHT...POSSIBLY LEADING TO LOCAL ENHANCEMENT OF WINDS. WINDS
VEER MORE WESTERLY BEHIND THE PASSING FRONT FRIDAY...REMAINING GUSTY
AT TIMES. WINDS INCREASE AND BECOME NORTHWEST FRIDAY NIGHT AND
SATURDAY. SCA/S WILL LIKELY BE NEEDED DURING THIS PERIOD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...KB
SHORT TERM...MB
LONG TERM...BA
AVIATION...MB
MARINE...MB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1208 AM EDT THU SEP 19 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 148 PM EDT WED SEP 18 2013
A WARM FRONT WILL PUSH NORTHWARD THROUGH LOWER MICHIGAN TONIGHT
LEADING TO SOME SHOWERS AND THUNDERSTORMS. SOUTHWEST WINDS WILL
INCREASE THURSDAY ALLOWING FOR AND UNSEASONABLY WARM DAY. MOISTURE
FROM THE GULF OF MEXICO WILL STREAM INTO THE AREA THURSDAY NIGHT
AND EARLY FRIDAY AHEAD OF A COLD FRONT. AS THIS FRONT PUSHES
THROUGH THE REGION FRIDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS
CAN BE EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 148 PM EDT WED SEP 18 2013
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE TIMING AND
STRENGTH OF THE CONVECTION. STORMS IN NW ILLINOIS ARE SHOWN TO
WEAKEN AS THEY HEAD TOWARD CHICAGO THIS AFTERNOON. HRRR SHOWS
CONVECTION REDEVELOPING OVER LAKE MI LATER TONIGHT AND MOVING INTO
THE HOLLAND TO MUSKEGON REGION. THIS MAKES SENSE WITH A
STRENGTHENING LOW LEVEL JET ACCOMPANYING THE WARM FRONT THAT
FEATURES ELEVATED INSTABILITY. NOT ALL MODELS HAVE THIS...BUT THE
HRRR TENDS TO HANDLE THE CONVECTION BETTER THAN MOST. WILL
DECREASE POPS INLAND TONIGHT...BUT CLOSER TO LAKE MI WILL KEEP THE
LIKELY VALUES GOING. SEVERE WEATHER IS NOT FORECASTED...BUT
PERHAPS A HEAVY RAIN THREAT MAY EXIST.
A LULL IN THE CONVECTION IS EXPECTED THU AS NO FOCUSING MECHANISM
IS SHOWN. IT WILL BE A WARM AND INCREASINGLY HUMID. IT DOES BECOME
RATHER UNSTABLE...SO WILL HOLD ONTO A LOW POP FOR STORMS.
I RAISED POPS FOR FRIDAY. WITH PWAT VALUES APPROACHING 2 INCHES
AND A FRONT PRESSING IN ALONG WITH LIFT...IT SHOULD BE RATHER WET
AT TIMES. MODELS HAVE TRENDED SOMEWHAT FASTER WITH THE FRONT...SO
WE MAY BE ABLE TO START DRYING THINGS OUT FROM THE WEST BEFORE THE
END OF THE DAY. WILL WAIT TO SEE IF THIS TREND PERSISTS BEFORE
CHANGING FRIDAYS FORECAST. I DID LOWER POPS FOR FRIDAY NIGHT
BECAUSE OF THIS. AS FOR SEVERE WEATHER...THE STRONGER DEEP LAYER
SHEAR IS SHOWN TO LAG BEHIND THE COLD FRONT...SO SOMEWHAT OF A
LIMITED RISK. STILL WITH BETTER INSTABILITY DEVELOPING AND
INCREASING WIND FIELDS ALONG WITH A LOW LEVEL JET MOVING IN AND
STRENGTHENING...A RISK STILL EXISTS. WILL NEED TO MONITOR TRENDS
CLOSELY IN THE COMING DAYS.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 243 PM EDT WED SEP 18 2013
AN UNEVENTFUL PERIOD IS EXCEPTED FOR THIS WEEKEND AND INTO THE
FIRST HALF OF NEXT WEEK. HIGH PRESSURE OVER THE UPPER MIDWEST ON
SATURDAY WILL SLOWLY MOVE OVER THE GREAT LAKES BY LATE IN THE
WEEKEND. THIS HIGH WILL BE STALLED OVER THE AREA AS A STORM SYSTEM
MOVES UP THE EAST COAST THROUGH THE FIRST HALF OF THE WORK WEEK.
SO FAIR WEATHER SHOULD PREVAIL.
LOWERED TEMPS A BIT FOR SATURDAY AND SUNDAY AS WE WILL BE UNDER A
THERMAL TROUGH . BOTH DAYS SHOULD SEE HIGHS STAYING IN THE 60S. WE
SHOULD SEE A WARM UP INTO THE WORK WEEK. HOWEVER LOW LEVEL FLOW
WILL BE FROM THE EAST OR SOUTHEAST...SO ANY MODERATION OF TEMPS
WILL BE GENTLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1159 PM EDT WED SEP 18 2013
THE POTENTIAL AND TIMING OF THUNDERSTORMS CONTINUES TO BE
PROBLEMATIC SO THIS IS A LOW CONFIDENCE FCST. TSTM COMPLEXES HAVE
DEVELOPED TO OUR SOUTH AND OUR NORTH ALTHOUGH NOTHING YET IN
BETWEEN THE TWO.
WILL NOT MAKE MUCH CHANGE FROM THE PREVIOUS TAFS... KEEPING VCTS
OVERNIGHT INTO THURSDAY MORNING BUT THIS IS QUESTIONABLE. A LULL
IN CONVECTIVE POTENTIAL IS STILL EXPECTED THURSDAY AFTERNOON AND
EVENING BEFORE THE NEXT DECENT CHANCE OF TSTMS WILL COME THURSDAY
NIGHT AFTER 06Z.
OUTSIDE OF ANY TSTMS...VFR IS EXPECTED OVER THE NEXT 24 HOURS.
HOWVER THERE COULD BE SOME LIGHT FOG/HAZE DEVELOPING LATE TONIGHT
AND THURSDAY AS HIGHER DEW POINTS COME IT...POSSIBLY GIVING MVFR
VSBYS IN SPOTS.
&&
.MARINE...
ISSUED AT 148 PM EDT WED SEP 18 2013
WINDS ARE FORECASTED TO BE STRONGER THU INTO THU NIGHT. MAY NEED
SMALL CRAFT AND BEACH HAZARDS TO COVER THIS. UNTIL THEN THE
SOUTHERLY FLOW WILL KEEP WAVES UP TO AROUND 2 TO 4
FEET...ESPECIALLY OFF OF LITTLE AND BIG SABLE POINTS.
&&
.HYDROLOGY...
ISSUED AT 148 PM EDT WED SEP 18 2013
LOCALIZED HEAVY RAIN WILL BE POSSIBLE WITH THE STORMS TONIGHT AS A
LOW LEVEL JET MOVES IN PWAT VALUES CLIMB TO OVER 1.5 INCHES.
CORFIDI VECTORS SUGGESTS A LOCALIZED HEAVY RAIN THREAT MAY EXIST.
CURRENTLY IT APPEARS THAT AREAS ALONG THE LAKESHORE STAND THE
HIGHEST CHANCE FOR THE STORMS. A MORE WIDESPREAD ROUND OF STORMS
IS FORECASTED FOR THU NIGHT INTO FRI. PWAT VALUES LIKELY TO CLIMB
ABOVE 1.75 INCHES WITH ANOTHER LOW LEVEL JET PUSHING THROUGH.
CORFIDI VECTORS ALSO SUGGEST A HEAVY RAIN THREAT. HOW MUCH RAIN
FALLS WILL LIKELY DEPEND ON HOW EFFICIENT THE RAIN BECOMES AND HOW
THE CONVECTION EVOLVES. SUSPECT LOCALLY MORE THAN 2 INCHES WILL
FALL BY FRI NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...MEADE
HYDROLOGY...MJS
MARINE...MJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 PM CDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 237 PM CDT THU SEP 19 2013
AS OF 2 PM...THE FRONT WAS STILL SLOWLY MOVING ACROSS THE EASTERN
HALF OF MINNESOTA...BUT IT HAD NOT PASSED THROUGH THE TWIN CITIES
METRO. EVEN WITH THE THE THUNDERSTORM ACTIVITY DIMINISHING IN
WESTERN WI...THERE IS STILL A NICE POOL OF INSTABILITY IN WI AND
EASTERN IA. THE STEEPEST CAPE GRADIENT EXTENDS FROM ROUGHLY EAU
CLAIRE...TO ALBERT LEA. THIS SAME AREA HAS SEEN MOSTLY CLEAR SKIES
SO FAR TODAY...BUT TOWERING CU HAS FILLED IN ACROSS MUCH OF THIS
AREA WITH SCATTERED SHOWERS. IF THERE IS TO BE CONVECTIVE REDEVELOP
IN THE MPX FORECAST AREA...THEN THIS IS THE SPOT TO KEEP AN EYE ON.
THERE IS A NICE SHORTWAVE IN EASTERN NE THAT SHOULD CONTINUE TO
DRIVE STORMS ACROSS IA. FARTHER NORTH THERE ARE FAR MORE QUESTIONS
AND WE THINK ACTIVITY WILL LARGELY REMAIN EAST AND SOUTH OF HERE.
THAT BEING SAID...THE 19.17Z HRRR HAS ANOTHER LINE OF STORMS GOING
RIGHT ALONG THE AFOREMENTIONED CAPE GRADIENT LATE THIS
AFTERNOON...AROUND 21Z FOR EAU CLAIRE.
OTHERWISE...LOOK FOR SOME NICE COLD ADVECTION TONIGHT AND TOMORROW
WITH A DRIER AND BREEZY NORTHWEST FLOW. THERE IS ACTUALLY A
SECONDARY COLD FRONT BACK ACROSS THE DAKOTAS ASSOCIATED WITH THAT
STRATO CU DECK AND TEMPS IN THE UPPER 40S AND LOWER 50S. THAT IS ON
TAP FOR TOMORROW. THE AIR WILL MODIFY...BUT WOULD NOT BE SURPRISED
IF SOME SITES IN CENTRAL MN STRUGGLE TO GET OUT OF THE 50S. WE
LOWERED HIGHS TOMORROW A BIT...BUT PROBABLY COULD HAVE GONE A COUPLE
DEGREES MORE. IT WILL BE A VERY FALL LIKE DAY TOMORROW.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 PM CDT THU SEP 19 2013
LOTS OF DISCREPANCIES EXIST IN THE LONG RANGE WITH RESPECT TO
TIMING OF INDIVIDUAL WAVES...BUT MODELS DO AGREE ON THE GENERAL
PROGRESSION OF THE LARGE SCALE UPPER AIR PATTERN. THE WEEKEND WILL
START WITH A RIDGE MOVING ACROSS THE NATIONS MID SECTION...BUT BY
MONDAY...AN ANOMALOUSLY STRONG UPPER RIDGE WILL BECOME CENTERED
OVER THE THE SE CONUS...WITH A DEEP TROUGH CARVING OUT ACROSS WRN
NOAM. DURING THE WEEK...THIS WRN TROUGH WILL SLOWLY DRIFT TOWARD
THE CENTRAL CONUS...APPROACHING THE UPPER MS VALLEY TOWARD THE END
OF NEXT WEEK.
SATURDAY STILL LOOKS TO START OUT IN THE UPPER 30S TO MID
40S...BUT DID NUDGE LOWS A COUPLE OF DEGREES UP...AS THE RIDGE
AXIS DOES NOT LOOK TO COME INTO WRN MN UNTIL CLOSER TO DAY
BREAK...KEEPING WINDS UP ENOUGH TO KEEP THE ATMO FROM COMPLETELY
DECOUPLING. OTHERWISE...ONLY THING REMOTELY SIGNIFICANT ABOUT THE
WEATHER THIS WEEKEND WILL BE THE BREEZY CONDITIONS DEVELOPING
SUNDAY AS GRADIENT TIGHTENS SIGNIFICANTLY ACROSS MN IN RESPONSE TO
A 1020 MB HIGH OVER THE GREAT LAKES AND A 995 MB LOW OVER THE WRN
DAKOTAS. 1000-850 WINDS OFF THE NAM INCREASE TO OVER 30 KTS BY THE
AFTERNOON IN WRN MN...SO SHOULD TURN INTO A FAIRLY BREEZY DAY IN
OUR TYPICALLY WINDY AREAS.
TIMING DETAILS QUICKLY SHOW UP WITH THE WAVE DUE TO MOVE THROUGH ON
MONDAY AS MODELS STRUGGLE TO PIN DOWN HOW THE RIDGING OVER THE
SOUTHEAST WILL IMPACT THE SPEED OF WAVES BACK THIS DIRECTION. THE
GEM/GFS CONTINUE TO BRING A POTENT NEGATIVELY TILTED THROUGH
ACROSS THE NRN PLAINS MONDAY...WITH A BAND OF SHRA/TSRA COMING
ALONG WITH AS WELL. THE 19.12 ECMWF SLOWED DOWN CONSIDERABLY WITH
THIS FEATURE...BRINGING IT THROUGH ABOUT 12 HRS LATER...WITH
PRECIP COMING THROUGH MONDAY NIGHT AS A RESULT. GIVEN TIMING
DIFFERENCES...CONTINUED WITH CHANCES POPS MON/MON NIGHT...BUT AT
SOME POINT...GIVEN THE DYNAMICS ASSOCIATED WITH THE NEGATIVELY
TITLED WAVE...WE SHOULD BE HEADING FOR A HIGH POP/LOW QPF TYPE
SCENARIO ONCE BETTER TIMING CAN BE NAILED DOWN. GIVEN THE RIDGING
TO THE SE...ITS USUALLY A SAFER BET TO GO THE SLOWER ROUTE.
THIS RIDGE TO THE SOUTHEAST WILL BE A MAJOR PLAYER FOR THE WEATHER
HERE THROUGH THE REST OF THE WEEK...AS IT WILL ACT TO DEFLECT
MUCH OF THE SHORTWAVE ENERGY TO THE NW OF THE MPX AREA. HAVE SEEN
MODELS RESPOND TO THIS...WITH EACH RUN GRADUALLY SLOWING DOWN WHEN
THE NEXT SYSTEM WILL IMPACT THE AREA. THE GFS WANTS TO BRING A
POTENT FRONT/LOW THROUGH WED NIGHT/THU...WHILE THE ECMWF HOLDS OFF
UNTIL FRIDAY. MUCH LIKE WAS STATED IN THE PREVIOUS
PARAGRAPH...GIVEN THE STRENGTH OF THE RIDGING TO THE SE...THE
SLOWER PROGRESSION WILL LIKELY BE THE WAY THINGS GO...BUT GIVEN
THE BLENDING PROCEDURE USED...PRECIP CHANCES RETURN WEDNESDAY.
THOUGH THERE IS UNCERTAINTY ABOUT PRECIP...WHAT IS MORE CERTAIN IS
THAT SW FLOW RESULTING FROM THE TROUGH WEST/RIDGE EAST WILL BRING
WITH IT TEMPERATURES WELL ABOVE NORMAL...WITH HIGHS IN THE 80S
LOOKING POSSIBLE BY THE MIDDLE OF NEXT WEEK...WHICH THANKS TO OUR
RAPIDLY FALLING AVERAGE HIGHS WOULD BE CLOSE 20 DEGREES ABOVE
NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU SEP 19 2013
IMMEDIATE CONCERN THIS AFTERNOON ACROSS THE AREA IS THE DEPARTING
THUNDER...BRIEF POST FRONTAL LOW CIGS...AND RAPIDLY
VARYING/CHANGING WIND DIRECTION. ALL MN TAF SITES ARE DONE WITH
THE THUNDER AT THIS POINT...BUT WESTERN WI WILL SEE ADDITIONAL
THUNDER FOR THE NEXT HOUR OR TWO. A NARROW AREA OF IFR CIGS BEHIND
THE FRONT HAS DEVELOPED AND WILL TRANSLATE EAST AS IT SLOWLY
DISSIPATES THIS AFTERNOON. THIS WILL NEED TO BE MONITORED TO SEE
HOW LONG IT HOLDS TOGETHER. WINDS TURN NW BY THIS EVE ACROSS THE
ENTIRE AREA...AND VFR CONDITIONS ARE EXPECTED BEHIND THE POST
FRONTAL STRATUS...UNTIL THE EARLY MORNING HOURS. AT THAT TIME...A
SHIELD OF LOW STRATUS WILL ADVECT IN FROM THE NORTHWEST...WITH THE
ENTIRE AREA SEEING MVFR CIGS...WITH THE POSSIBILITY OF IFR
CEILINGS BEFORE SUNRISE. CIGS WILL LIFT TO VFR BY LATE
MORNING/EARLY AFTERNOON. WINDS TOMORROW WILL BE GUSTY FROM THE NORTHWEST.
KMSP...VFR CONDITIONS SHOULD PREVAIL UNTIL THE OVERNIGHT HOURS
WHEN THE LOW STRATUS APPROACHES NEAR SUNRISE. ADVERTISING MVFR
CIGS 10-16Z...BUT BEWARE OF THE POTENTIAL FOR CEILINGS CLOSER TO
1K FT FROM AROUND 10-13Z. WINDS WILL BE NW BY TONIGHT AND REMAIN
THAT WAY THROUGH THE TAF PERIOD. MVFR CIGS LIFT DUE TO MIXING TO
VFR BY LATE MORNING.
/OUTLOOK FOR KMSP/
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...MPG
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
238 PM CDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 237 PM CDT THU SEP 19 2013
AS OF 2 PM...THE FRONT WAS STILL SLOWLY MOVING ACROSS THE EASTERN
HALF OF MINNESOTA...BUT IT HAD NOT PASSED THROUGH THE TWIN CITIES
METRO. EVEN WITH THE THE THUNDERSTORM ACTIVITY DIMINISHING IN
WESTERN WI...THERE IS STILL A NICE POOL OF INSTABILITY IN WI AND
EASTERN IA. THE STEEPEST CAPE GRADIENT EXTENDS FROM ROUGHLY EAU
CLAIRE...TO ALBERT LEA. THIS SAME AREA HAS SEEN MOSTLY CLEAR SKIES
SO FAR TODAY...BUT TOWERING CU HAS FILLED IN ACROSS MUCH OF THIS
AREA WITH SCATTERED SHOWERS. IF THERE IS TO BE CONVECTIVE REDEVELOP
IN THE MPX FORECAST AREA...THEN THIS IS THE SPOT TO KEEP AN EYE ON.
THERE IS A NICE SHORTWAVE IN EASTERN NE THAT SHOULD CONTINUE TO
DRIVE STORMS ACROSS IA. FARTHER NORTH THERE ARE FAR MORE QUESTIONS
AND WE THINK ACTIVITY WILL LARGELY REMAIN EAST AND SOUTH OF HERE.
THAT BEING SAID...THE 19.17Z HRRR HAS ANOTHER LINE OF STORMS GOING
RIGHT ALONG THE AFOREMENTIONED CAPE GRADIENT LATE THIS
AFTERNOON...AROUND 21Z FOR EAU CLAIRE.
OTHERWISE...LOOK FOR SOME NICE COLD ADVECTION TONIGHT AND TOMORROW
WITH A DRIER AND BREEZY NORTHWEST FLOW. THERE IS ACTUALLY A
SECONDARY COLD FRONT BACK ACROSS THE DAKOTAS ASSOCIATED WITH THAT
STRATO CU DECK AND TEMPS IN THE UPPER 40S AND LOWER 50S. THAT IS ON
TAP FOR TOMORROW. THE AIR WILL MODIFY...BUT WOULD NOT BE SURPRISED
IF SOME SITES IN CENTRAL MN STRUGGLE TO GET OUT OF THE 50S. WE
LOWERED HIGHS TOMORROW A BIT...BUT PROBABLY COULD HAVE GONE A COUPLE
DEGREES MORE. IT WILL BE A VERY FALL LIKE DAY TOMORROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU SEP 19 2013
STRONG CAA IN THE WAKE OF THE COLD FRONT AND RESULTANT STEEP LOW
LEVEL LAPSE RATES WILL PROMOTE GUSTY WINDS AND A DEVELOPMENT OF
STRATOCU BEGINNING LATE TONIGHT TO THE NORTH AND WEST...PUSHING
OVERHEAD FRIDAY. MODEST AMOUNTS OF INSTABILITY THROUGH THE CLOUD-
BEARING LAYER MAY ALSO BRING A FEW SPRINKLES TO THE REGION...
PARTICULARLY NORTH OF THE MINNESOTA RIVER. LIGHT QPF ON THE
NAM/GFS/ECMWF ALSO HINT TOWARD THIS. THUS...INCREASED CLOUDS AND
WINDS...AND DECREASED TEMPERATURES FRIDAY FROM THE LAST FORECAST
PACKAGE.
THE HIGH WILL PUSH ACROSS WESTERN MINNESOTA FRIDAY NIGHT.
FORECAST SOUNDINGS REMAIN QUITE MIXED...BUT AM A BIT SKEPTICAL OF
THIS WITH THE SURFACE HIGH SO NEARBY. CLOUDS WILL QUICKLY
DISSIPATE FRIDAY EVENING AS CYCLONIC FLOW PUSHES OUT...SETTING THE
STAGE FOR A COLD NIGHT OVER THE AREA WITH LOWS IN THE MID 30S TO
LOWER 40S.
UPPER RIDGING QUICKLY BUILDS BACK OVER THE PLAINS DURING THE
WEEKEND. A FAIRLY IMPRESSIVE TEMPERATURE GRADIENT IS POSSIBLE ON
EITHER SIDE OF THE SURFACE RIDGE AXIS ACROSS THE CWA SATURDAY
AFTERNOON.
A SOUTHEASTERLY SURFACE FLOW WILL ENVELOP THE ENTIRE AREA FROM
SUNDAY INTO EARLY NEXT WEEK AS A SOUTHWEST FLOW IN THE UPPER
ATMOSPHERE STEERS WEAKENING SYSTEMS TO THE NORTH. ONE SUCH SYSTEM
WILL LIMP THROUGH MONDAY/MONDAY NIGHT. WITH RIDGING BUILDING IN
IMMEDIATELY IN THE WAKE OF THE SYSTEM...A DE-AMPLIFICATION OF SAID
SYSTEM WILL TAKE PLACE AND LITTLE OR NO FORCING WILL ACCOMPANY
WHAT IS LEFT OF THE FRONT. THUS...MAINTAINED ONLY LOW POPS.
WINDS WILL VEER MORE SOUTHERLY MIDWEEK WITH WARMER AND MORE HUMID
AIR RETURNING. MODELS ARE INCONSISTENT WITH THE POSITIONING OF A
SW-NW ORIENTED SURFACE BOUNDARY WITH THE EC FURTHER NORTH THAN
THE GFS. GFS SOLUTION WOULD BRING HIGHER POPS. EITHER
WAY...TEMPERATURES SHOULD BE 10-15 DEGREES ABOVE AVERAGE DURING
THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU SEP 19 2013
IMMEADITE CONCERN THIS AFTERNOOON ACROSS THE AREA IS THE DEPARTING
THUNDER...BRIEF POST FRONTAL LOW CIGS...AND RAPIDLY
VARYING/CHANGING WIND DIRECTION. ALL MN TAF SITES ARE DONE WITH
THE THUNDER AT THIS POINT...BUT WESTERN WI WILL SEE ADDITIONAL
THUNDER FOR THE NEXT HOUR OR TWO. A NARROW AREA OF IFR CIGS BEHIND
THE FRONT HAS DEVELOPED AND WILL TRANSLATE EAST AS IT SLOWLY
DISSIPATES THIS AFTERNOON. THIS WILL NEED TO BE MONITIORED TO SEE
HOW LONG IT HOLDS TOGETHER. WINDS TURN NW BY THIS EVE ACROSS THE
ENTIRE AREA...AND VFR CONDITIONS ARE EXPECTED BEHIND THE POST
FRONTAL STRATUS...UNTIL THE EARLY MORNING HOURS. AT THAT TIME...A
SHIELD OF LOW STRATUS WILL ADVECT IN FROM THE NORTHWEST...WITH THE
ENTIRE AREA SEEING MVFR CIGS...WITH THE POSSIBILITY OF IFR
CEILINGS BEFORE SUNRISE. CIGS WILL LIFT TO VFR BY LATE
MORNING/EARLY AFTERNOON. WINDS TOMORROW WILL BE GUSTY FROM THE NORTHWEST.
KMSP...VFR CONDITIONS SHOULD PREVAIL UNTIL THE OVERNIGHT HOURS
WHEN THE LOW STRATUS APPROACHES NEAR SUNRISE. ADVERTISING MVFR
CIGS 10-16Z...BUT BEWARE OF THE POTENTIAL FOR CEILINGS CLOSER TO
1K FT FROM AROUND 10-13Z. WINDS WILL BE NW BY TONIGHT AND REMAIN
THAT WAY THROUGH THE TAF PERIOD. MVFR CIGS LIFT DUE TO MIXING TO
VFR BY LATE MORNING.
/OUTLOOK FOR KMSP/
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...BORGHOFF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS BILLINGS MT
238 PM MDT THU SEP 19 2013
.SHORT TERM...VALID FOR FRI AND SAT...
UPPER TROF CONTINUES TO SHIFT EAST AND WE ARE BEGINNING TO SEE
HEIGHT RISES INTO CENTRAL MT. SOME LIGHT SHOWERS REMAIN EAST OF
MILES CITY...ASSOCIATED WITH WEAK SHORTWAVE EMBEDDED IN THE NW
FLOW ALOFT...BUT THIS ACTIVITY IS WEAKENING AND WILL BE DONE
BEFORE 00Z.
ISSUES FOR TONIGHT INCLUDE FOG AND FROST POTENTIAL. PLENTY OF
CLOUD COVER CURRENTLY EXISTS IN OUR EAST BUT THIS WILL BE
DISSIPATING INTO THE EVENING. CURRENT DEWPTS ARE NOTEWORTHY...IN
THE UPPER 30S TO AROUND 40...AND WILL NOT SEE ANY SIGNIFICANT LOW
LEVEL DRYING IN OUR EAST BEFORE SUNSET. WITH THIS IN MIND...AND AS
SFC RIDGE BUILDS TO THE SOUTHEAST ALLOWING FOR THE NWLY GRADIENT
TO RELAX...BELIEVE SOME FOG OR STRATUS DEVELOPMENT IS POSSIBLE IN
OUR EAST. MIGHT LEAN TOWARD PATCHY VALLEY FOG HERE AS RAP SHOWS A
DECENT NW WIND AT 850MB THRU 12Z. WITHOUT ANY STRATUS BELIEVE SOME
AREAS IN OUR FAR EAST WILL SEE SOME FROST WITH TEMPS INTO THE MID
30S TONIGHT. IN OUR WEST...CLEAR SKIES A CERTAINTY WITH ONLY WEAK
DOWNSLOPE GRADIENTS DEVELOPING AFTER MIDNIGHT. SO BELIEVE
NOTORIOUSLY COLDER SPOTS SUCH AS HARLOWTON...LIVINGSTON AND
SHERIDAN WILL SEE SOME FROST TONIGHT. DEWPTS ARE PROBABLY TOO HIGH
TO SUPPORT A REAL FREEZE THOUGH. GENERALLY SPEAKING HAVE LOWERED
TEMPS FOR TONIGHT A BIT MORE...AND THIS IS CONSISTENT WITH THE
SLOWER PROGRESSING UPPER TROF AND COOLING TREND IN ALL GUIDANCE.
FOR BILLINGS...COULD SEE MID OR UPPER 30S FOR LOWS ALONG THE
YELLOWSTONE VALLEY...BUT RIDGES SHOULD NOT FALL BELOW THE LOW 40S.
DRY WX WITH A WARMING TREND IN STORE FOR FRI/SAT AS STRONG RIDGE
ALOFT BUILDS OVER THE REGION. EXPECT TEMPS TO CLIMB BACK INTO THE
70S TOMORROW AND 80S ON SAT...WITH GOOD CONFIDENCE IN A STRONG
WARM UP SUPPORTED BY DRY AIRMASS SETTLING IN AND WHAT WILL BE DEW
PTS IN THE 20S AND 30S. DEEPER MIXING OF INCREASED SW WINDS ALOFT
WILL RESULT IN GUSTY WINDS FOR OUR WESTERN FOOTHILLS INCLUDING
LIVINGSTON ON SAT...WHICH WILL COINCIDE WITH AFTN RHS IN THE LOW
TEENS. THESE CONDITIONS WILL BE HIGHLIGHTED IN THE FIRE WEATHER
FORECAST.
NEXT PACIFIC TROF...THOUGH WEAKENING AS IT COMES INLAND...WILL
BEGIN TO IMPACT OUR FAR WEST LATE SAT NIGHT. HAVE SCALED BACK POPS
SLIGHTLY AND PUSHED THEM WEST AFTER 06Z...BASED ON MODEL CONSENSUS
FOR THIS SLOWER TIMING. WEAK COLD FRONT WILL ALLOW FOR COOLER
PACIFIC AIR TO BEGIN SPREADING IN FROM THE WEST LATE SAT NITE...
SETTING UP A COOLER SUNDAY.
JKL
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
THE EXTENDED FORECAST LOOKS A LOT MORE LIKE FALL WITH TWO WEATHER
SYSTEMS TO WATCH. THE FIRST SYSTEM WILL IMPACT THE REGION ON
SUNDAY...AND WILL BRING SOME SNOW SHOWERS TO HIGH ELEVATIONS IN
THE MOUNTAINS AND RAIN SHOWERS ACROSS THE REST OF THE FORECAST
AREA...BRINGING TEMPERATURES BACK TO NEAR SEASONAL NORMALS. THE
SECOND SYSTEM...WHICH IS MUCH MORE INTERESTING...WILL IMPACT THE
REGION BY WEDNESDAY AND THURSDAY...AND WILL BRING MUCH BELOW
NORMAL TEMPERATURES AND A GOOD CHANCE OF WIDESPREAD PRECIPITATION.
...SUNDAY THROUGH TUESDAY...
A SPLITTING TROUGH WILL CROSS THE REGION ON SUNDAY...BRINGING AN
INCREASE IN PACIFIC MOISTURE AND QG FORCING ACROSS THE FORECAST
AREA. ELEVATED MOUNTAIN LOCATIONS WILL LIKELY CATCH SOME SNOW
SHOWERS WITH THIS SYSTEM AS H7 TEMPS DECREASE TO AROUND 0C. WINDS
WILL REMAIN MOSTLY WESTERLY AND DOWNSLOPE...WHICH WILL ACT TO
LIMITE THE AMOUNT OF PRECIPITATON ACROSS THE PLAINS LOCATIONS.
HOWEVER...FULLY EXPECT A COOLER AND CLOUDY DAY WITH SCATTERED RAIN
SHOWERS ACROSS THE PLAINS. THE FLOW BEHIND THE WAVE FOR MONDAY AND
TUESDAY WILL REMAIN NEAR ZONAL WITH THE JET OVERHEAD...KEEPING
TEMPERATURES NEAR NORMAL AND A CHANCE OF SOME SHOWERS IN THE
MOUNTAINS...OTHERWISE THE REMAINDER OF THE FORECAST AREA SHOULD
STAY DRY.
...WEDNESDAY AND THURSDAY...
GLOBAL MODELS ARE EXTREMELY CONSISTENT WITH THE WEATHER PATTERN
OVER THE PACIFIC BY THIS TIME FRAME...AND ALL DEVELOP A DIGGING
TROUGH DOWN THE WEST COAST BY TUESDAY INTO WEDNESDAY. THE PATTERN
WILL OPEN THE DOOR TO MUCH COOLER TEMPERATURES FOR WEDNESDAY AND
THURSDAY. WHILE THERE ARE MINOR DIFFERENCES IN THE EVOLUTION OF
THE TROUGH...BOTH THE GFS AND ECMWF POSITION THE LOW JUST TO OUR
WEST BY WEDNESDAY AFTERNOON AND SLIDE THE LOW ACROSS OUR SOUTH BY
THURSDAY. THIS SOLUTION IS FAVORABLE FOR A PROLONGED UPSLOPE
EVENT. THAT COMBINED WITH THE DYNAMICS OF THE LOW COULD PRODUCE A
WIDESPREAD PRECIPITATION EVENT ACROSS THE AREA...AND IN PARTICULAR
ALONG THE FOOTHILLS AND EAST FACING MOUNTAIN LOCATIONS.
TEMPERATURES ARE COOL ENOUGH THAT SNOW IN THE MOUNTAINS WOULD BE
LIKELY AND COULD GET INTO HIGH FOOTHILLS LOCATIONS. TEMPERATURES
ACROSS THE PLAINS WOULD CERTAINLY BE THE COOLEST WE HAVE SEEN THIS
FALL...BUT AT THIS POINT LOOK JUST WARM ENOUGH FOR MAINLY RAIN
EVENT. THIS WEATHER SYSTEM WILL BE THE ONE TO WATCH AS IT BECOMES
CLOSER IN TIME.
CHURCH
&&
.AVIATION...
THE LOWER CLOUD DECK WILL CONTINUE TO ERODE FROM WEST TO EAST
ACROSS THE AREA AS DRIER AIR WORKS IN FROM THE WEST. MVFR CEILINGS
SHOULD BE LIMITED TO FAR EASTERN MONTANA...NEAR KBHK THIS
AFTERNOON. OTHERWISE VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF
SITES OVERNIGHT. WINDS WILL ALSO CONTINUE TO DECREASE THROUGH THIS
EVENING. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 043/075 050/084 054/069 048/071 048/068 047/055 043/052
00/U 00/U 12/T 11/B 02/T 23/W 44/W
LVM 034/078 042/086 047/065 042/068 043/065 043/048 038/047
00/U 00/N 22/T 11/B 12/T 23/W 44/W
HDN 038/078 046/086 051/073 046/073 045/073 047/059 044/054
00/U 00/U 02/T 21/B 01/B 13/W 44/W
MLS 040/075 049/084 054/075 051/075 050/075 050/063 047/057
00/U 00/U 02/T 21/U 11/B 13/W 44/W
4BQ 038/074 044/084 053/076 046/074 046/074 047/065 046/056
00/U 00/U 02/T 21/U 11/U 12/W 33/W
BHK 036/070 043/080 050/077 046/073 044/075 045/064 048/057
00/U 00/U 02/T 21/U 11/U 12/W 44/W
SHR 035/076 045/084 050/072 044/071 045/073 044/060 042/051
00/U 00/U 02/T 30/U 01/U 12/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
906 AM MDT THU SEP 19 2013
.UPDATE...
WEAK SHORTWAVE IN NW FLOW ALOFT IS INTERACTING WITH SHALLOW BUT
MOIST LOW LEVEL INSTABILITY TO PRODUCE AREAS OF LIGHT SHOWERS OR
SPRINKLES FROM NEAR COLUMBUS EAST. IN FACT...CONVERGENT BAND HAS
DEVELOPED DOWNWIND OF THE SNOWIES...THUS THE LIGHT SHOWERS IN THE
BILLINGS AREA AT 9AM WITH A VEERED-TO-NORTH WIND. THIS ACTIVITY
SHOULD END BY NOON IN OUR WEST...BUT STRONGER ASCENT AND DEEPER
MOISTURE WILL IMPACT OUR EAST INTO THE AFTERNOON. RAP/NAM
SOUNDINGS SHOW MOIST LOW LEVELS PERSISTING THRU THE AFTERNOON.
HAVE THUS RAISED AND EXPANDED POPS FROM MILES CITY TO BAKER AND
EKALAKA...AND DROPPED TEMPS JUST A BIT. PRECIP AMOUNTS WILL BE
LIGHT BUT SHOULD AMOUNT TO A FEW HUNDREDTHS. TEMP AT BAKER COULD
STRUGGLE TO RISE ABOVE THE LOW 50S TODAY...ALONG WITH A BRISK NW
WIND WITH GUSTS TO 30 MPH. EASILY THE COOLEST DAY WE HAVE SEEN IN
A LONG TIME. JKL
&&
.SHORT TERM...VALID FOR TDY AND FRI...
UPPER TROUGH CROSSING THE REGION TONIGHT WILL CONTINUE TO EXERT
ITS INFLUENCE OVER OUR FORECAST AREA WELL INTO THURSDAY...
ESPECIALLY IN THE NORTHEAST ZONES. AS SUCH...SOME CHANGES HAVE
BEEN MADE FOR TODAY FORECAST.
EARLY THIS MORNING...THE MAIN 500MB COLD POOL WAS SITUATED OVER
SOUTHWEST MONTANA. THERE WAS ANOTHER MID LEVEL COLD POOL OVER
NORTH CENTRAL MONTANA AS WELL WITH AN ASSOCIATED FRONT PUSHING
EAST/SOUTHEAST ACROSS MONTANA. THIS FEATURE WILL SLIP DOWN
THROUGH OUR ZONES BY 6AM. THERE IS A CONSISTENT EFFORT FROM THE
MODELS TO BRING IN A LOW CLOUD DECK BEHIND THIS FEATURE...THICKEST
ACROSS CUTER AND FALLON COUNTIES. WHILE SOUNDINGS AND HRRR DATA
PARTIALLY BREAK MILES CITY OUT OF THIS IN THE AFTERNOON...THEY
SUGGEST BAKER AND FALLON COUNTY WILL PERSIST UNDER OVERCAST
CONDITIONS AS LONG AS 6PM. THIS SCENARIO IS A NOTORIOUS FORECAST
BUSTER FOR BAKER. UNLESS I SEE SOMETHING AT THE LAST MOMENT
SUGGESTING OTHERWISE...I WILL PLAN TO LOWER TEMPERATURES QUITE A
BIT IN THIS AREA.
ANOTHER CHANGE...THOUGH MINOR...WAS IN REGARD TO A TROWEL FEATURE
ON THE BACKSIDE OF THE TROUGH. THIS IS CURRENTLY GENERATING SOME
PRECIPITATION ALONG THE FRONT RANGE AND NORTHWEST MOUNTAINS. CROSS
SECTIONS SHOW SOME MODEST LIFT AND MOISTURE AS IT WORKS OVER OUR
FORECAST AREA THIS MORNING. IT WILL HAVE TO BATTLE A BRISK
DOWNSLOPE WIND...SO VIRGA AND SPRINKLES MAY BE THE MAIN
OUTCOME. HOWEVER...I HAVE SPREAD SOME LOW POPS BACK TO THE WEST
AS WELL AS A LITTLE FURTHER SOUTH INTO UPSLOPE AREAS NEAR THE BIG
HORNS FOR THE FIRST HALF OF THE DAY.
THE TROUGH AXIS WILL BE JUST EAST OF THE MONTANA/DAKOTA BORDER
BY EVENING. SO WE SHOULD SEE DECREASING CLOUDS AND WIND. LOWS MAY
DIP TO AROUND OR JUST BELOW AVERAGE FOR THIS TIME OF YEAR...MAKING
IT ONE OF THE OVERALL COOLEST WE HAVE HAD SO FAR THIS SEPTEMBER.
RIDGE BUILDS IN QUICKLY FOR TOMORROW WHICH WILL RESULT IN A NICE
BUMP IN THE MERCURY. BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS IN GOOD AGREEMENT FOR THIS WEEKEND GOING INTO
EARLY NEXT WEEK BUT DIVERGE WITH A LARGE SYSTEM ACROSS THE WESTERN
STATES BY MID NEXT WEEK. RIDGE AND ITS AXIS SHIFT EAST SATURDAY AS
AN UPPER LOW AND TROUGH MOVE ONTO THE PACIFIC NORTHWEST AND
NORTHERN CALIFORNIA COAST. SOUTHWEST FLOW ALOFT WILL PREVAIL ALONG
WITH ABOVE NORMAL TEMPERATURES AND A SLIGHT SHOWER/THUNDERSTORM
CHANCE. THE TROUGH ALONG WITH A COLD FRONT MOVE THROUGH THE
FORECAST AREA LATE SATURDAY NIGHT INTO SUNDAY MORNING BRINGING
BETTER CHANCES FOR SHOWERS WITH COOLER AND MORE NORMAL
TEMPERATURES FOR SUNDAY.
FAST ZONAL FLOW ALOFT LOOKS IN STORE FOR MONDAY AND TUESDAY WITH
MAINLY A DOWNSLOPE SURFACE FLOW KEEPING CONDITIONS DRY FOR THE
LOWER ELEVATIONS WITH SHOWERS FOR THE MOUNTAINS. BY LATE TUESDAY
INTO WEDNESDAY...AN UPPER LOW TAKES SHAPE ACROSS THE PACIFIC
NORTHWEST. MODELS DIVERGE GREATLY FROM THAT POINT ONWARD. THE GFS
TAKES THE LOW SOUTH INTO THE GREAT BASIN AREA WEDNESDAY AND
THURSDAY WHILE THE ECMWF EJECTS THE LOW NORTHEAST ACROSS MONTANA
BUT STILL KEEPING A TROUGH ACROSS THE CENTRAL AND NORTHERN
ROCKIES. EITHER SCENARIO WILL BRING INCREASING CHANCES FOR PRECIP
TO THE FORECAST AREA. HOWEVER...LOCATION AND AMOUNTS OF PRECIP
ALONG WITH TEMPEATURES VARY QUITE A BIT DEPENDING ON MODEL. WILL
KEEP CHANCE POPS FOR MID NEXT WEEK WITH HIGHEST CHANCES FOR THE
MOUNTAINS ALONG WITH A TREND TO COOLER TEMPERATURES. HOOLEY
&&
.AVIATION...
EXPECT MOSTLY CLOUDY SKIES TODAY WITH VFR CONDITIONS PREVAILING.
THE EXCEPTION WILL BE ISOLATED TO SCATTERED SHOWERS POSSIBLE ALONG
AND NORTH OF A KLVM - KBIL - KBHK LINE TODAY WHICH WILL RESULT IN
POSSIBLE MVFR CONDITIONS AT TIMES. MVFR TO IFR CONDITIONS WILL
ALSO BE POSSIBLE AT TIMES DUE TO LOW CEILINGS FROM KMLS EASTWARD.
GUSTY NORTHWEST WINDS WILL BE LIKELY EAST OF KBIL TOWARD KMLS TO
THE DAKOTA BORDERS. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 064 043/077 049/084 053/068 048/071 050/071 048/062
2/W 00/U 00/U 22/T 11/B 02/T 22/W
LVM 064 035/078 043/083 046/065 042/068 045/068 045/054
0/B 00/U 00/U 22/T 11/B 12/T 23/W
HDN 066 038/079 045/086 051/072 046/073 049/074 048/065
2/W 00/U 00/U 12/T 21/B 01/B 12/W
MLS 059 042/075 048/084 054/073 050/075 052/074 050/068
6/W 00/U 00/U 22/T 21/U 11/B 12/W
4BQ 061 038/075 045/084 053/075 047/074 049/075 047/068
2/W 00/U 00/U 12/T 21/U 11/U 12/W
BHK 055 037/072 044/080 050/075 047/073 048/074 047/069
6/W 00/U 00/U 12/T 21/U 11/U 12/W
SHR 063 036/076 046/084 050/070 044/071 047/072 045/064
1/B 00/U 00/U 12/T 30/U 01/U 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
318 AM MDT THU SEP 19 2013
.SHORT TERM...VALID FOR TDY AND FRI...
UPPER TROUGH CROSSING THE REGION TONIGHT WILL CONTINUE TO EXERT
ITS INFLUENCE OVER OUR FORECAST AREA WELL INTO THURSDAY...
ESPECIALLY IN THE NORTHEAST ZONES. AS SUCH...SOME CHANGES HAVE
BEEN MADE FOR TODAYS FORECAST.
EARLY THIS MORNING...THE MAIN 500MB COLD POOL WAS SITUATED OVER
SOUTHWEST MONTANA. THERE WAS ANOTHER MID LEVEL COLD POOL OVER
NORTH CENTRAL MONTANA AS WELL WITH AN ASSOCIATED FRONT PUSHING
EAST/SOUTHEAST ACROSS MONTANA. THIS FEATURE WILL SLIP DOWN
THROUGH OUR ZONES BY 6AM. THERE IS A CONSISTENT EFFORT FROM THE
MODELS TO BRING IN A LOW CLOUD DECK BEHIND THIS FEATURE...THICKEST
ACROSS CUSTER AND FALLON COUNTIES. WHILE SOUNDINGS AND HRRR DATA
PARTIALLY BREAK MILES CITY OUT OF THIS IN THE AFTERNOON...THEY
SUGGEST BAKER AND FALLON COUNTY WILL PERSIST UNDER OVERCAST
CONDITIONS AS LONG AS 6PM. THIS SCENARIO IS A NOTORIOUS FORECAST
BUSTER FOR BAKER. UNLESS I SEE SOMETHING AT THE LAST MOMENT
SUGGESTING OTHERWISE...I WILL PLAN TO LOWER TEMPERATURES QUITE A
BIT IN THIS AREA.
ANOTHER CHANGE...THOUGH MINOR...WAS IN REGARD TO A TROWEL FEATURE
ON THE BACKSIDE OF THE TROUGH. THIS IS CURRENTLY GENERATING SOME
PRECIPITATION ALONG THE FRONT RANGE AND NORTHWEST MOUNTAINS. CROSS
SECTIONS SHOW SOME MODEST LIFT AND MOISTURE AS IT WORKS OVER OUR
FORECAST AREA THIS MORNING. IT WILL HAVE TO BATTLE A BRISK
DOWNSLOPE WIND...SO VIRGA AND SPRINKLES MAY BE THE MAIN
OUTCOME. HOWEVER...I HAVE SPREAD SOME LOW POPS BACK TO THE WEST
AS WELL AS A LITTLE FURTHER SOUTH INTO UPSLOPE AREAS NEAR THE BIG
HORNS FOR THE FIRST HALF OF THE DAY.
THE TROUGH AXIS WILL BE JUST EAST OF THE MONTANA/DAKOTA BORDER
BY EVENING. SO WE SHOULD SEE DECREASING CLOUDS AND WIND. LOWS MAY
DIP TO AROUND OR JUST BELOW AVERAGE FOR THIS TIME OF YEAR...MAKING
IT ONE OF THE OVERALL COOLEST WE HAVE HAD SO FAR THIS SEPTEMBER.
RIDGE BUILDS IN QUICKLY FOR TOMORROW WHICH WILL RESULT IN A NICE
BUMP IN THE MERCURY. BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS IN GOOD AGREEMENT FOR THIS WEEKEND GOING INTO
EARLY NEXT WEEK BUT DIVERGE WITH A LARGE SYSTEM ACROSS THE WESTERN
STATES BY MID NEXT WEEK. RIDGE AND ITS AXIS SHIFT EAST SATURDAY AS
AN UPPER LOW AND TROUGH MOVE ONTO THE PACIFIC NORTHWEST AND
NORTHERN CALIFORNIA COAST. SOUTHWEST FLOW ALOFT WILL PREVAIL ALONG
WITH ABOVE NORMAL TEMPERATURES AND A SLIGHT SHOWER/THUNDERSTORM
CHANCE. THE TROUGH ALONG WITH A COLD FRONT MOVE THROUGH THE
FORECAST AREA LATE SATURDAY NIGHT INTO SUNDAY MORNING BRINGING
BETTER CHANCES FOR SHOWERS WITH COOLER AND MORE NORMAL
TEMPERATURES FOR SUNDAY.
FAST ZONAL FLOW ALOFT LOOKS IN STORE FOR MONDAY AND TUESDAY WITH
MAINLY A DOWNSLOPE SURFACE FLOW KEEPING CONDITIONS DRY FOR THE
LOWER ELEVATIONS WITH SHOWERS FOR THE MOUNTAINS. BY LATE TUESDAY
INTO WEDNESDAY...AN UPPER LOW TAKES SHAPE ACROSS THE PACIFIC
NORTHWEST. MODELS DIVERGE GREATLY FROM THAT POINT ONWARD. THE GFS
TAKES THE LOW SOUTH INTO THE GREAT BASIN AREA WEDNESDAY AND
THURSDAY WHILE THE ECMWF EJECTS THE LOW NORTHEAST ACROSS MONTANA
BUT STILL KEEPING A TROUGH ACROSS THE CENTRAL AND NORTHERN
ROCKIES. EITHER SCENARIO WILL BRING INCREASING CHANCES FOR PRECIP
TO THE FORECAST AREA. HOWEVER...LOCATION AND AMOUNTS OF PRECIP
ALONG WITH TEMPEATURES VARY QUITE A BIT DEPENDING ON MODEL. WILL
KEEP CHANCE POPS FOR MID NEXT WEEK WITH HIGHEST CHANCES FOR THE
MOUNTAINS ALONG WITH A TREND TO COOLER TEMPERATURES. HOOLEY
&&
.AVIATION...
EXPECT PARTLY TO MOSTLY CLOUDY SKIES TODAY WITH VFR CONDITIONS
PREVAILING. THE EXCEPTION WILL BE ISOLATED TO SCATTERED SHOWERS
POSSIBLE ALONG AND NORTH OF A KLVM- KBIL-KBHK LINE TODAY WHICH
WILL RESULT IN POSSIBLE MVFR CONDITIONS AT TIMES. MVFR TO IFR
CONDITIONS WILL ALSO BE POSSIBLE AT TIMES DUE TO LOW CEILINGS FROM
KMLS EASTWARD. GUSTY NORTHWEST WINDS WILL BE LIKELY FROM KBIL
EASTWARD BUT ESPECIALLY TOWARD KMLS TO THE DAKOTA BORDERS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 065 043/077 049/084 053/068 048/071 050/071 048/062
1/B 00/U 00/U 22/T 11/B 02/T 22/W
LVM 064 035/078 043/083 046/065 042/068 045/068 045/054
0/B 00/U 00/U 22/T 11/B 12/T 23/W
HDN 066 038/079 045/086 051/072 046/073 049/074 048/065
2/W 00/U 00/U 12/T 21/B 01/B 12/W
MLS 059 042/075 048/084 054/073 050/075 052/074 050/068
2/W 00/U 00/U 22/T 21/U 11/B 12/W
4BQ 062 038/075 045/084 053/075 047/074 049/075 047/068
1/B 00/U 00/U 12/T 21/U 11/U 12/W
BHK 056 037/072 044/080 050/075 047/073 048/074 047/069
2/W 00/U 00/U 12/T 21/U 11/U 12/W
SHR 063 036/076 046/084 050/070 044/071 047/072 045/064
1/B 00/U 00/U 12/T 30/U 01/U 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
122 PM CDT THU SEP 19 2013
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
SURFACE COLD FRONT AT 18Z EXTENDED FROM SOUTH OF KOMA TO SOUTH OF
KLNK WILL CONTINUE TO MOVE SLOWLY SOUTHEASTWARD THROUGH THE
FORECAST PERIOD. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
AT KOMA AND KLNK THROUGH 21Z. SOME STORMS MAY BECOME SEVERE SOUTH
AND EAST OF KLNK THROUGH 19/00Z. CEILINGS ARE EXPECTED TO REMAIN
ABOVE MVFR RANGE IN THUNDERSTORM AREAS. JUST BEHIND THE
FRONT...CEILINGS MAY DROP BRIEFLY INTO MVFR RANGE BEFORE BECOMING
VFR THE REMAINDER OF THE PERIOD.
SMITH
&&
DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
729 AM CDT THU SEP 19 2013
.AVIATION...
12Z TAFS FOR KOMA...KOFK...KLNK
THE SURFACE COLD FRONT WILL MOVE THROUGH OFK BY MID MORNING AND
OMA/LNK BY EARLY AFTERNOON. SCT SHRA AND ISO TSRA ARE EXPECTED
WITH THE FRONT AT ALL 3 TAF SITES WITH SOME MVFR VISBY
POSSIBLE...BUT CIGS ARE EXPECTED TO REMAIN ABOVE MVFR RANGE. WILL
INCLUDE THUNDER AT ALL 3 SITES FOR A COUPLE OF HOURS...BUT THE
MAJORITY OF THE TIME IT WILL LIKELY BE JUST SHOWERS. THE PRECIP
WILL CLEAR OUT OF THE TAF SITES BY LATE AFTERNOON WITH SKIES
CLEARING OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 251 AM CDT THU SEP 19 2013/
DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
251 AM CDT THU SEP 19 2013
.DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.AVIATION...06Z TAFS FOR KOFK...KOMA AND KLNK.
A COLD FRONT IS STILL ON TRACK TO CROSS TAF SITES THURSDAY WITH
SCATTERED SHOWERS AND THUNDERSTORMS MOSTLY ALONG OR BEHIND FRONT.
FIRST ROUND OF CONVECTION OVER WRN NEBR COULD MOVE ACROSS KOFK
VICINITY THURSDAY MORNING AND FORECAST WILL REFLECT THIS. ALTHOUGH
SOME OF THIS ACTIVITY COULD IMPACT KLNK AND KLNK...TSTMS WERE NOT
MENTIONED AT THOSE SITES UNTIL AFTERNOON WHEN ADDITIONAL
DEVELOPMENT IS EXPECTED AND CHANCES APPEARED HIGHER. THUS PROB30
GROUPS IN 00Z FORECAST WERE UPGRADED TO TEMPO GROUPS AT BOTH
KLNK AND KOMA. SHOWERS/ISOLD TSTMS COULD LINGER INTO EARLY
THURSDAY EVENING BEFORE MOVING TO THE EAST.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1111 PM MDT WED SEP 18 2013
.AVIATION...
06Z TAF CYCLE
MTS OCCASIONALLY OBSCURED. ISOLD CONVECTION TO PERSIST AND MOVE
GENLY NORTHEAST TO EAST OVER NRN AND CENTRAL NM THROUGH THE
OVERNIGHT HOURS AS UPPER DISTURBANCE TRACKS EAST OVER THE REGION.
LOCALIZED MVFR CIGS/VSBYS IN TSRA WILL BE POSSIBLE ALONG WITH
SFC WND GUSTS TO 35KT. LOCAL MVFR CIGS POSSIBLE FROM THE CENTRAL
MT CHAIN ACROSS THE EASTERN PLAINS AFT 08Z TO AROUND 15Z THURSDAY.
SFC FRONT TO APPROACH FAR NE NM BY 15Z THURSDAY WITH SCT
CONVECTION DVLPG THEREAFTER FROM THE CENTRAL MT CHAIN TO THE TX
BORDER.
&&
.PREV DISCUSSION...256 PM MDT WED SEP 18 2013...
ANOTHER ACTIVE WX SCENARIO SHAPING UP OVER THE REGION FOR REMAINDER
OF TODAY THRU THURSDAY. CIRA LAYERED TOTAL PW PRODUCT SHOWS ABUNDANT
LOW/MID LEVEL MOISTURE ACROSS THE REGION WITH VERY DRY CONDITIONS
ALOFT. VALUES ARE ON THE ORDER OF 130-160 PCT OF NORMAL. A THIN 30-
50 KT UPPER JET AXIS OVER NM AS SEEN ON THE LATEST AMDAR DATA IS
INTERACTING WITH THE LOW LEVEL MOISTURE AND INSTABILITY TO PRODUCE
A WELL DEFINED BAND OF THUNDERSTORMS OVER WESTERN AND NORTHERN NM.
STEERING FLOWS ARE STRONG TODAY HOWEVER THE SHEAR AXIS IS ORIENTED
IN THE DRXN OF STORM MOTION SO MORE LOCALLY HEAVY RAINFALL ON TAP.
LATEST HRRR SHOWS THIS AREA OF SHOWERS AND STORMS PROPAGATING EVER
SO SLOWLY EAST THIS EVENING INTO THE RIO GRANDE VALLEY AND NEARBY
HIGH TERRAIN. HAVE RAISED POPS TO HIGH CHANCE AND LIKELY FOR CENTRAL
NM.
EVEN MORE ACTIVE CONDITIONS WILL TAKE SHAPE INTO THURSDAY NIGHT BUT
MORE INTO THE EASTERN PLAINS. A LARGE UPPER TROUGH OVER THE PACIFIC
NW WILL SLIDE EAST INTO THE GREAT PLAINS AND HELP DRIVE A SURFACE
BACK DOOR FRONTAL BOUNDARY INTO NM. MEANWHILE...A VERY WELL DEFINED
UPPER WAVE EMBEDDED ON THE BACK SIDE OF THE LARGE SCALE WAVE WILL
SLIDE OVER NORTHERN NM AND HELP LIFT FOCUS OVER FRONT. CURRENT QPF
VALUES ARE POTENTIALLY TOO LOW FOR THIS EVENT ACROSS THE EAST WHERE
SUBSTANTIALLY MOISTURE REMAINS IN PLACE. FLOODING IS NOT EXPECTED
HOWEVER SOME LOCALIZED IMPACTS ARE LIKELY IF THE RAIN FALLS OVER
THE WRONG SPOT. ALSO RAISED POPS FOR THE EASTERN PLAINS THURSDAY
NIGHT TO LIKELY. TEMPS THROUGH THIS PERIOD WILL COOL BELOW NORMAL
FOR MUCH OF THE REGION...ESPECIALLY THE EAST.
MODELS DO INDICATE STRONGER WESTERLIES AND DRIER AIR SHIFTING EAST
INTO THE STATE FRIDAY THRU SUNDAY HOWEVER STRONG MOISTURE RECYCLING
PROCESSES WILL STILL BE AT PLAY. LOW CLOUDS AND FOG ARE POSSIBLE
ANY NIGHT ESPECIALLY IF SKIES CLEAR AND WINDS TAPER OFF. TEMPS WILL
BE COOL OUT WEST WHERE MUCH DRIER DEWPOINTS WILL MOVE IN. THE
EXTENDED PATTERN IS STILL HIGHLY UNCERTAIN SO MADE NO CHANGES. THE
ECMWF PROGS A DEEP LARGE SCALE STATIONARY UPPER LOW OVER THE GREAT
BASIN WITH A RELATIVELY ABUNDANT MONSOONAL MOISTURE TAP OVER NM. THE
GFS HAS AN EVEN DEEPER TIGHTLY WOUND COLD UPPER LOW DRIVING EAST
ACROSS THE CENTRAL ROCKIES THRU MID WEEK.
GUYER
&&
.FIRE WEATHER...
SCATTERED WETTING THUNDERSTORMS FOUND ACROSS WESTERN AND NORTHERN
AREAS WILL TRANSITION EASTWARD THIS EVENING BEFORE DIMINISHING SOME.
DRIER AIR WILL EVENTUALLY FILL IN FROM WEST TO EAST LATER TONIGHT
AND WILL SET THE STAGE FOR A DRIER WESTERN AND CENTRAL AREAS ON
THURSDAY.
A BACK DOOR COLD FRONT IS STILL EXPECTED FOR THURSDAY WITH EASTERN
AREAS OBSERVING THAT INFLUENCE. THIS INCLUDES WETTING SHOWERS AND
THUNDERSTORMS WHICH WOULD FAVOR MOST OF THE EASTERN PLAINS THURSDAY
AFTERNOON INTO THE OVERNIGHT. MIXING HEIGHTS WILL INCREASE ACROSS
THE MAJORITY OF THE AREA ALTHOUGH TRANSPORT WINDS WILL COME DOWN
MOST AREAS SO VENTILATION RATES WILL LOWER PRETTY MUCH AREAWIDE.
THE BACK DOOR COLD FRONT WILL PUSH THROUGH THE CENTRAL MOUNTAINS
THURSDAY NIGHT AND MOST LIKELY MAKE IT TO THE AZ STATE LINE BY
FRIDAY MORNING. MIXING DURING FRIDAY AFTERNOON SHOULD SET UP A
CONVERGENCE BOUNDARY NEAR THE CONTINENTAL DIVIDE AND MOST LIKELY
PROVIDE A FOCUS FOR THUNDERSTORMS THERE. THE ATMOSPHERE COULD BE TOO
STABLE FOR SIGNIFICANT SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL AND EASTERN AREAS DUE TO RESIDUAL IMPACTS FROM THE COLD
FRONT. HUMIDITY VALUES WILL BE UNSEASONABLY HIGH FRIDAY AFTERNOON.
TEMPERATURES WILL BE COOLER THAN NORMAL CENTRAL AND EASTERN AREAS
WHILE BEING NEAR NORMAL WEST OF THE CONTINENTAL DIVIDE. VENTILATION
RATES WILL BE LOWEST EXTENDING FROM ZONE 109 NORTHEASTWARD OVER THE
MIDDLE RIO GRANDE VALLEY AND AREAS TO THE LEE OF THE SANGRE DE
CRISTOS.
THE NEXT PACIFIC TROUGH WILL PLUNGE INTO THE FAR WESTERN US SATURDAY
AND CONTINUE TO TRAVERSE ACROSS THE INTERMOUNTAIN WEST ON SUNDAY.
MOISTURE WILL TRY TO SEEP UP FROM MEXICO AHEAD OF THIS TROUGH SO
LOOK FOR UNSETTLED WEATHER ACROSS THE WEST ON SATURDAY TRANSITIONING
SOME EASTWARD ON SUNDAY. WETTING RAIN WOULD CERTAINLY BE POSSIBLE
ALTHOUGH NOT AS WIDESPREAD AS THE PREVIOUS WEEK. HUMIDITY IS
EXPECTED TO TREND UP ACROSS THE WEST ON SATURDAY WHILE LOWER ACROSS
THE EAST. ON SUNDAY...HUMIDITY IS EXPECTED TO LOWER AREAWIDE
ALTHOUGH THIS COULD CHANGE. VENTILATION WILL INCREASE DURING THE
WEEKEND THANKS TO STRONGER WEST/SOUTHWEST TRANSPORT WIND. CONFIDENCE
IS PRETTY GOOD THAT A PACIFIC TROUGH WILL IMPACT THE AREA BUT STILL
NOT TOTALLY SURE ABOUT HOW MUCH MOISTURE WILL SEEP UP FROM THE SOUTH
AND FEED THE TROUGH. SURFACE WIND SHOULD ALSO INCREASE DURING THE
WEEKEND PERIOD.
ANOTHER PACIFIC TROUGH IS EXPECTED TO AFFECT THE WESTERN US BY THE
MIDDLE OF NEXT WEEK. THE LONG RANGE MODELS DIFFER SOMEWHAT IN THE
EXTENSION SOUTHWARD OF THE TROUGH BUT EITHER WAY IMPACT POTENTIAL
WOULD INCREASE BY MID NEXT WEEK. DEPENDING ON HOW THE TROUGH COMES
IN...ADDITIONAL WETTING RAIN WOULD BE POSSIBLE. CONDITIONS FOLLOWING
THE TROUGH PASSAGE COULD LEAD TO THE MOUNTAINS FIRST BIG FREEZE OF
THE FALL SEASON SO WILL BE WATCHING THAT AS THAT WOULD BEGIN THE
CURING PROCESS TO THE ABUNDANT FUELS THAT HAVE GREENED UP THIS SUMMER.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
950 PM EDT FRI SEP 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL GIVER WAY TO LOW PRESSURE TONIGHT
AND SATURDAY WITH SURFACE FRONT EXPECTED TO CROSS THE AREA SATURDAY
NIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA FOR THE FIRST PART OF
THE WEEK. A SYSTEM WILL APPROACH FROM THE SOUTH WEDNESDAY AND MOVE
EAST OF THE THE AREA THURSDAY WITH HIGH PRESSURE BUILDING BACK IN
BY THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 950 PM FRIDAY...PATCHY SHOWERS HAVE INCREASED A BIT IN
COVERAGE OVER THE PAST COUPLE OF HOURS AND HAVE RAISED POPS
SLIGHTLY OVER THE FAR WESTERN COUNTIES WITH POPS INCREASING EAST
TOWARD THE HIGHWAY 17 CORRIDOR TOWARD MORNING AS 3 KM HRRR AND RUC
CONTINUES TO SHOW SCATTERED LIGHT SHOWERS OVER THE WESTERN TWO-
THIRDS OF OUR CWA. NO REAL CHANGES IN FORECAST TEMPERATURES
OVERNIGHT AS TEMPS WILL MUCH MILDER THAN RECENT NIGHTS AS THE LOW-
LEVELS MOISTEN AND THE FLOW BECOMES SE/S.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
AS OF 124 PM FRI...HIGH PRESSURE ALOFT WILL WEAKEN THROUGH THE DAY
ON SATURDAY AS FULL LATITUDE TROUGH APPROACHES FROM THE WEST. UPPER
LOW OFF THE COAST WILL BE ABSORBED BY THE APPROACHING SYSTEM.
SURFACE REFLECTION FRONT WILL APPROACH THE AREA DURING THE
DAY...WITH SURFACE FLOW BECOMING SOUTHWESTERLY AND PICKING UP IN
SPEED TO 10 TO 15 MPH. AS FRONT APPROACHES WITH WEAK UPPER LEVEL
FORCING...WILL HAVE SMALL BUT INCREASED POPS. HIGHEST CHANCES WILL
BE IN WESTERN SECTIONS DURING THE LATER AFTERNOON...BUT WILL KEEP
POPS AROUND 30 IN THOSE AREAS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
SHORT WAVE EMBEDDED IN THE DIGGING FULL LATITUDE TROF DEVELOPING
OVER THE EASTERN STATES WILL PASS THRU THE FORECAST AREA SAT
NIGHT. GIVEN THE GOOD MID LEVEL MOISTURE INFLOW FROM THE GULF
REGION AND SFC MOIST FLOW OFF THE ATLANTIC HAVE UPPED POPS TO
LIKELY SAT NIGHT. INSTABILITY WILL BE LIMITED DUE TO THE
UNFAVORABLE DIURNAL CYCLE BUT WILL HANG ONTO ISOLD TSTM MENTION
GIVEN THE MODEST SHEAR, MAINLY FOR SAT EVE AREAWIDE THEN SHIFTING
TO THE COAST AFTER MIDNIGHT. SHORTER RANGE MODELS ARE IN DECENT
AGREEMENT PUSHING THE SFC COLD FRONT THRU THE AREA OVERNIGHT AND
OFFSHORE BY DAYBREAK SUNDAY. RAINFALL TOTALS DO NOT LOOK TO BE
IMPRESSIVE GIVEN THE RELATIVELY FAST MOVING SYSTEM WITH GENERAL
ONE HALF INCH AMOUNTS EXPECTED AND LOCALLY HIGHER AMOUNTS.
SFC BNDRY SAGS SOUTH OF THE REGION ON SUNDAY. CUD BE SOME
LEFTOVER PRECIP ESP OVER SOUTHERN AREAS BUT MOST OF SUNDAY INTO
SUNDAY NIGHT SHUD BE DRY WITH GRADUALLY CLEARING AS HIGH PRESSURE
RIDGES IN FROM THE NW. BROAD EAST COAST TROF WILL PUSH OFFSHORE
EARLY NEXT WEEK AS SHORT WAVE RIDGE SLIDES EAST TO THE NORTHERN
MID ATLC STATES. SOUTHERN STREAM SYSTEM UNDERCUTS THE RIDGE OVER
THE GULF COAST AND SE STATES WHICH WILL THROW CLOUDS AND LOW
PRECIP CHANCES AS FAR NORTH AS EASTERN NC DURING MIDWEEK.
UPPER RIDGE BUILDS OVER SE STATES IN THE WAKE OF THE SOUTHERN
STREAM SYSTEM MOVING OFF THE COAST LATE IN THE WEEK...WITH A
RETURN TO MAINLY CLEAR SKIES...COOL NIGHTS AND MILD DAYS.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 645 PM FRI...GIVEN SKIES THAT HAVE REMAINED RELATIVELY
CLEAR AT THE TAF SITES...AND WITH LOW-LEVEL FLOW BECOMING MORE
SE/S TOWARD MORNING...AM A BIT MORE CONCERNED ABOUT THE
DEVELOPMENT OF FOG AND STRATUS TOWARD MORNING AS ALL OF THE
NUMERICAL MOS GUIDANCE INDICATES LOW CEILINGS AND VSBYS AFTER 08Z
OR SO. WILL BE A BIT MORE CONSERVATIVE...BUT WILL INDICATE A
PERIOD OF MVFR VSBYS/CEILINGS TOWARD MORNING. GENERALLY VFR FOR
MOST OF SATURDAY AS PRECIPITATION SHOULD NOT BECOME MORE
WIDESPREAD UNTIL LATER IN THE DAY.
LONG TERM /SAT NIGHT THROUGH WEDNESDAY/...
SHOWERS/ISOLD TSTMS AHEAD OF A COLD FRONT SAT NIGHT WILL LIKELY
BRING PERIODS OF SUB-VFR CONDITIONS. GRADUAL IMPROVEMENT IN FLYING
CONDITIONS ON SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH
THROUGH EARLY NEXT WEEK. FRINGE EFFECTS OF A SOUTHERN STREAM
SYSTEM MOVING OFF THE SE COAST WILL BRING CLOUDINESS AND PRECIP
CHANCES BACK INTO THE AREA TUE NIGHT AND WEDNESDAY WITH SUB-VFR
CONDITIONS POSSIBLE.
&&
.MARINE...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 950 PM FRI...GENERALLY SEEING A ENE/E WIND ALONG THE COASTAL
WATERS AT SOUNDS WITH WIND SPEEDS AT 10 TO 15 KNOTS. THESE WINDS
SHOULD GRADUALLY VEER TO A MORE SE/S DIRECTION TOWARD MORNING AS
AXIS OF HIGH PRESSURE RIDGE MOVES OFFSHORE AS A COLD FRONT
APPROACHES. WIND SPEEDS SHOULD BE 15 KNOT OR LESS WITH SEAS
GENERALLY 2 TO 4 FEET WITH LONG PERIOD 10 TO 11 SECOND SWELLS. AS
THE FRONT APPROACHES THE AREA SATURDAY...BRINGING WIND TO A
SOUTHERLY DIRECTION...AND INCREASING SPEEDS TO 10 TO 15 KNOTS AS
GRADIENT INCREASING AHEAD OF THE APPROACHING FRONT. SEAS WILL
REMAIN 2 TO 4 FEET THROUGH THE PERIOD. OVERALL NO BIG CHANGES TO
THE FORECAST.
LONG TERM /SAT NIGHT THROUGH WEDS/...
MODERATE SW FLOW AHEAD OF A COLD FRONT PASSAGE SAT NIGHT WILL
SHIFT WEST THEN NW AND DECREASING SLIGHTLY ON SUNDAY. THE MAIN
PUSH OF COLD AIR ADVECTION WILL MOVE DOWN THE NC COAST LATE SUNDAY
NIGHT/EARLY MONDAY WITH N/NE WINDS (AND SEAS) APPROACHING SMALL
CRAFT ADVISORY LEVELS. LIGHT TO MODERATE NE WINDS WILL CONTINUE
THRU THE EARLY PART OF THE WEEK THEN INCREASE SOMEWHAT AS LOW
PRESSURE PASSES OFF THE SE COAST DURING MIDWEEK.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CGG
NEAR TERM...CTC
SHORT TERM...CGG
LONG TERM...BTC
AVIATION...CTC/BTC/BM
MARINE...CTC/BTC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 AM CDT THU SEP 19 2013
.UPDATE...
ISSUED AT 645 AM CDT THU SEP 19 2013
NO SIGNIFICANT CHANGES WITH THIS UPDATE. THE FORECAST FOR THE
REMAINDER OF THE DAY WAS BLENDED TO THE 10 UTC RAP AND 06 UTC NAM
GIVEN THEIR GOOD HANDLE OF THE STRATUS FIELD THAT IS OVERTAKING
THE AREA. DID LOWER HIGHS A FEW DEGREES FROM THE PREVIOUS FORECAST
ALONG AND WEST OF HIGHWAY 83 AS LOW LEVEL COLD AIR ADVECTION AND
CLOUD COVER WILL SIGNIFICANTLY LIMIT TEMPERATURE RECOVERY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 256 AM CDT THU SEP 19 2013
LATEST WATER VAPOR IMAGERY SHOWS A DRY SLOT COVERING MOST OF
WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. UPPER LOW CIRCULATING
OVER NORTHEAST MONTANA IS FORECAST TO SHIFT EAST INTO THE DEVILS
LAKE AREA BY THURSDAY NIGHT. INSTABILITY SHOWERS WILL CONTINUE TO WRAP
AROUND THE LOW AND SLIDE MAINLY ACROSS NORTHERN NORTH DAKOTA TODAY.
HAVE REMOVED THE MENTION OF THUNDER WITH SOUNDINGS SHOWING A STABLE
PATTERN ALONG WITH A HIGH RH FIELD IN THE H85-H7 LAYER. THE
NAM/RUC H85 RH FIELD SHOWS A LARGE SHIELD OF CLOUDY SKIES MOVING
SOUTHEAST FROM SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA. THIS
IS VERIFIED ON THE FOG/STRATUS LOOP. PATCHY FOG WAS ALSO
ACCOMPANYING THE STRATUS DECK. SOUNDINGS INDICATE BREEZY WINDS
TODAY WITH THE STRONGEST WINDS IN THE SOUTHWEST...HOWEVER WILL NOT
ISSUE A WIND ADVISORY AS WINDS ARE FORECAST TO REMAIN BELOW
CRITERIA...AS MIXING WILL BE LIMITED DUE TO THE EXTENSIVE LOW
LEVEL CLOUD COVER FORECAST TODAY. HIGHS WILL BE IN THE UPPER 50S
WEST TO AROUND 70F FAR SOUTHEAST. WILL NEED TO MONITOR THE FAR
SOUTHWEST FOR A POSSIBLE FROST ADVISORY FRIDAY MORNING AS CLEARING
SKIES ARRIVE LATE THURSDAY NIGHT WITH HETTINGER POSSIBLY DOWN TO
35F FOR A LOW TEMPERATURE. ELSEWHERE...EXPECT A SLOW DECREASE IN
CLOUDS FOR CENTRAL NORTH DAKOTA THURSDAY NIGHT WHICH WILL HELP TO
KEEP OVERNIGHT LOWS IN THE LOWER 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 AM CDT THU SEP 19 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE FROST POTENTIAL FRIDAY
NIGHT AND THUNDERSTORMS SUNDAY NIGHT INTO MONDAY.
THE 00 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON COOL SURFACE
HIGH PRESSURE ACROSS WESTERN AND CENTRAL NORTH DAKOTA ON FRIDAY.
GIVEN LITTLE MIXING AND A COOL MORNING START...WIDESPREAD HIGHS IN
THE LOW TO MID 60S ARE FORECAST...WHICH PERHAPS A FEW READINGS IN
THE 50S ACROSS THE TURTLE MOUNTAINS AND JAMES RIVER VALLEY.
SURFACE HIGH PRESSURE PROPAGATES INTO FAR WESTERN MINNESOTA FRIDAY
NIGHT...WITH RETURN FLOW COMMENCING ACROSS WESTERN NORTH DAKOTA.
HOWEVER...THE COOL DAYTIME TEMPERATURES FRIDAY SET THE STAGE FOR
FROST POTENTIAL WITH WIDESPREAD LOWS IN THE 30S POSSIBLE FOR
CENTRAL NORTH DAKOTA WHERE RETURN FLOW WILL NOT ESTABLISH ITSELF.
THEREAFTER...TEMPERATURES TREND BACK TO NEAR TO SLIGHTLY ABOVE
NORMAL WITH HIGHS IN THE 70S SATURDAY AND SUNDAY UNDER A HIGH
AMPLITUDE UPPER LEVEL RIDGE. THE 00 UTC DETERMINISTIC MODELS ALL
DEPICT A POTENT SHORTWAVE PROPAGATING INTO THE NORTHERN PLAINS
SUNDAY NIGHT INTO MONDAY...WITH WIDESPREAD CONVECTION POSSIBLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM CDT THU SEP 19 2013
LATEST SATELLITE AND SURFACE OBSERVATIONS SHOW MVFR/IFR CIGS
ACROSS THE NORTHERN AERODROMES OF KISN/KMOT. ANOTHER AREA OF MVFR
CIGS IN EASTERN MONTANA WILL SWEEP INTO KDIK BY 13Z...INTO KBIS BY
AROUND 15Z...AND KJMS BY MID AFTERNOON. MVFR CIGS WILL BE LOCKED
IN PLACE THROUGH 03Z FRIDAY WITH A GRADUAL RETURN TO VFR IN THE
WEST BY 06Z AND CENTRAL BETWEEN 06Z AND 12Z FRIDAY. BREEZY
NORTHWEST WINDS OF 15 TO 25 MPH CAN BE EXPECTED ACROSS
WESTERN/CENTRAL NORTH DAKOTA TODAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...KS
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
634 AM EDT THU SEP 19 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CHANCE OF
SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SHOWERS AND
A FEW THUNDERSTORMS WILL CONTINUE INTO SATURDAY BEFORE A DRIER AND
COOLER AIRMASS SETTLES INTO THE REGION FOR THE FIRST PART OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A PERSISTENT MCV HAS BEEN PROGRESSING VERY SLOWLY SOUTHEAST ACROSS
NORTHERN INDIANA THROUGH THE OVERNIGHT HOURS. SO FAR IT HAS NOT
SHOWED TOO MAY SIGNS OF DISSIPATING OR EVEN WEAKENING AND THE LAST SEVERAL
RUNS OF THE HRRR HAVE BEEN CONSISTENTLY TRYING TO PUSH IT
SOUTHEAST INTO OUR AREA THROUGH MID MORNING. THE AIRMASS ACROSS
OUR AREA IS MORE STABLE WITH THE INSTABILITY GRADIENT DROPPING OFF
FAIRLY QUICKLY ACROSS EASTERN INDIANA INTO WESTERN OHIO. AS A
RESULT..WOULD EXPECT THE BETTER CHANCE OF THUNDERSTORM MAINTENANCE
TO WORK MORE TO THE SOUTH AND STAY WEST OF MOST OF OUR AREA
THROUGH THE MORNING HOURS. HOWEVER...THE 850-300 MB MEAN WIND IS
MORE WESTERLY ACROSS NORTHERN INDIANA...BECOMING SOUTHEASTERLY
ACROSS OUR AREA. THIS WOULD SUGGEST A DECENT CHANCE THAT SOME OF
THE SHOWER ACTIVITY WILL WORK ITS WAY INTO AT LEAST THE WESTERN
HALF OF OUR FA OVER THE NEXT SEVERAL HOURS.
MEANWHILE...ABUNDANT LOW LEVEL MOISTURE ACROSS OUR AREA HAS ALLOWED
FOR SOME FAIRLY WIDESPREAD STRATUS DEVELOPMENT ACROSS ABOUT THE
SOUTHEAST TWO THIRDS OF OUR FA. WITH THE LOW LEVELS REMAINING MIXY
THROUGH DAYBREAK...WOULD NORMALLY NOT BE SURPRISED TO SEE THE
STRATUS EXPAND A LITTLE MORE...BUT THE DEBRIS CLOUDS FROM THE MCV
MAY MITIGATE THIS TO SOME DEGREE. EITHER WAY...THE COMBINATION OF
THE DEBRIS CLOUDS AND STRATUS DECK SHOULD KEEP US MAINLY CLOUD
THROUGH THE MORNING HOURS. THIS MAY ALSO HAVE AN IMPACT ON
TEMPERATURES AND HOW WELL WE DESTABILIZE THROUGH THIS AFTERNOON. IN
THE WESTERLY TO SOUTHWESTERLY LOW LEVEL WAA PATTERN...WOULD EXPECT
TO SEE SOME DECENT EROSION/DISSIPATION OF THE LOWER CLOUDS
THROUGH LATE MORNING/EARLY AFTERNOON WHICH SHOULD EVENTUALLY ALLOW
FOR PARTLY SUNNY SKIES. WILL NUDGE DOWN HIGHS JUST A TAD...GENERALLY
RANGING FROM UPPER 70S EAST TO LOWER 80S WEST. THIS WOULD STILL
ALLOW US TO DESTABILIZE THROUGH THIS AFTERNOON WITH ML CAPES PUSHING
UP CLOSE TO 1000 J/KG. AS A RESULT...WILL GO AHEAD AND ALLOW FOR
SOME CHANCE POPS ACROSS MUCH OF THE AREA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE 00Z NAM/GFS AND CMC ARE ALL TRYING TO HINT AT SOME SORT OF
CONTINUING PCPN OR REDEVELOPMENT TONIGHT SOMEWHERE ACROSS OUR AREA
WHILE THE 00Z ECMWF IS DRY. IT DOES LOOK LIKE WE COULD BE ON THE
EDGE OF A SOUTHWEST TO NORTHEAST ORIENTED 925-850 MB LOW LEVEL
JET LATER TONIGHT AND THIS COULD SERVE AS A FOCUSING MECHANISM.
AS A RESULT..WILL HANG ON TO SOME LOWER END POPS...BUT CONFIDENCE
IS NOT ALL THAT HIGH.
A COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT. AHEAD OF
THIS...WE SHOULD WARM UP FAIRLY WELL THROUGH THE DAY WITH HIGHS
PUSHING UP INTO THE LOW TO MID 80S. THIS WILL ALLOW US TO
DESTABILIZE ONCE AGAIN WITH MLCAPES AGAIN UP CLOSE TO 1000 J/KG.
THIS SHOULD LEAD TO SOME SCATTERED PRE FRONTAL SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. BETTER LOW LEVEL CONVERGENCE JUST
AHEAD OF THE FRONT WILL PUSH INTO OUR NORTHWEST LATE FRIDAY
AFTERNOON AND THEN PROGRESS SOUTHEAST ACROSS OUR AREA THROUGH FRIDAY
EVENING. THIS WILL ALLOW FOR A MORE ORGANIZED LINE OF SHOWERS AND
THUNDERSTORMS. DEEP LAYER SHEAR IS NOT TERRIBLY STRONG INITIALLY WITH
THE PCPN FRIDAY AFTERNOON/FRIDAY EVENING...BUT THE 0-3 KM SHEAR
VALUES DO PUSH UP INTO THE 25 TO 30 KNOT RANGE. THIS MAY BE
ENOUGH TO SUPPORT SOME MARGINALLY SEVERE STORMS LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING....ESPECIALLY ACROSS OUR NORTHWEST.
AS THE FRONT PUSHES OFF TO THE SOUTHEAST...EXPECT PCPN TO TAPER
OFF FROM NORTHWEST TO SOUTHEAST DURING THE DAY ON SATURDAY.
HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD INTO THE AREA THROUGH
THE LATER PART OF THE WEEKEND. HIGHS ON SATURDAY WILL BE IN THE 70-75
DEGREE RANGE WITH HIGHS ON SUNDAY IN THE UPPER 60S TO NEAR 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. COULD SEE
ENOUGH MOISTURE FROM THE LOW MOVING UP THE COAST TO PRODUCE
ISOLATED SHOWERS IN THE EXTREME EAST. AFTER MONDAY...SURFACE HIGH
PRESSURE EXTENDING INTO THE REGION FROM THE NE WILL BRING DRY
WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE NEXT
SEVERAL DAYS UNTIL A COLD FRONT PUSHES THROUGH SATURDAY MORNING.
MOISTURE CONTINUES TO INCREASE OVER THE OHIO VALLEY...RESULTING IN
INCREASING CLOUDS...SHOWERS AND A FEW THUNDERSTORMS.
THE SHOWER AND THUNDERSTORM COMPLEX WHICH ORIGINATED OVER NORTHERN
ILLINOIS LATE YESTERDAY EVENING CONTINUES TO PUSH SOUTHEAST AND IS CURRENTLY
LOCATED OVER CENTRAL INDIANA AND WEST CENTRAL OHIO. THIS PRECIPITATION
COMPLEX IS EXPECTED TO MOVE THROUGH THE AREA THIS MORNING AND
EARLY AFTERNOON. THERE IS A RISK OF THUNDERSTORMS WITH THIS
COMPLEX OVER THE WESTERN TAF SITES AND THIS HAS BEEN INCLUDED IN
THE FORECAST. AHEAD OF THIS AREA CONDITIONS ARE IFR DUE TO FOG AND
STRATUS. AS THE PRECIPITATION MOVES INTO THESE AREAS THE IFR
CONDITIONS SHOULD IMPROVE RAPIDLY. IN THE RAIN AREAS AFTER THE IFR
CONDITIONS HAVE IMPROVED EXPECT VFR WITH MVFR CIGS AND VSBY IN
THE HEAVIER SHOWERS AND THUNDERSTORMS.
ONCE THESE CONDITIONS MOVE TO THE EAST AND SOUTHEAST OF THE
FORECAST AREA THERE SHOULD BE A SIGNIFICANT BREAK WHERE VFR
CONDITIONS DOMINATE THE FORECAST AREA WELL INTO THE NIGHTTIME
HOURS. THEN FOG AND POSSIBLE STRATUS ONCE AGAIN WILL RETURN.
THESE CONDITIONS ARE MENTIONED IN THE FORECAST BUT TIMING AND
AREAL EXTENT OF COVERAGE WILL HAVE TO BE FINE TUNED IN LATER
FORECASTS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...PARKER
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
401 AM EDT THU SEP 19 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CHANCE OF
SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SHOWERS AND
A FEW THUNDERSTORMS WILL CONTINUE INTO SATURDAY BEFORE A DRIER AND
COOLER AIRMASS SETTLES INTO THE REGION FOR THE FIRST PART OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A PERSISTENT MCV HAS BEEN PROGRESSING VERY SLOWLY SOUTHEAST ACROSS
NORTHERN INDIANA THROUGH THE OVERNIGHT HOURS. SO FAR IT HAS NOT
SHOWED TOO MAY SIGNS OF DISSIPATING OR EVEN WEAKENING AND THE LAST SEVERAL
RUNS OF THE HRRR HAVE BEEN CONSISTENTLY TRYING TO PUSH IT
SOUTHEAST INTO OUR AREA THROUGH MID MORNING. THE AIRMASS ACROSS
OUR AREA IS MORE STABLE WITH THE INSTABILITY GRADIENT DROPPING OFF
FAIRLY QUICKLY ACROSS EASTERN INDIANA INTO WESTERN OHIO. AS A
RESULT..WOULD EXPECT THE BETTER CHANCE OF THUNDERSTORM MAINTENANCE
TO WORK MORE TO THE SOUTH AND STAY WEST OF MOST OF OUR AREA
THROUGH THE MORNING HOURS. HOWEVER...THE 850-300 MB MEAN WIND IS
MORE WESTERLY ACROSS NORTHERN INDIANA...BECOMING SOUTHEASTERLY
ACROSS OUR AREA. THIS WOULD SUGGEST A DECENT CHANCE THAT SOME OF
THE SHOWER ACTIVITY WILL WORK ITS WAY INTO AT LEAST THE WESTERN
HALF OF OUR FA OVER THE NEXT SEVERAL HOURS.
MEANWHILE...ABUNDANT LOW LEVEL MOISTURE ACROSS OUR AREA HAS ALLOWED
FOR SOME FAIRLY WIDESPREAD STRATUS DEVELOPMENT ACROSS ABOUT THE
SOUTHEAST TWO THIRDS OF OUR FA. WITH THE LOW LEVELS REMAINING MIXY
THROUGH DAYBREAK...WOULD NORMALLY NOT BE SURPRISED TO SEE THE
STRATUS EXPAND A LITTLE MORE...BUT THE DEBRIS CLOUDS FROM THE MCV
MAY MITIGATE THIS TO SOME DEGREE. EITHER WAY...THE COMBINATION OF
THE DEBRIS CLOUDS AND STRATUS DECK SHOULD KEEP US MAINLY CLOUD
THROUGH THE MORNING HOURS. THIS MAY ALSO HAVE AN IMPACT ON
TEMPERATURES AND HOW WELL WE DESTABILIZE THROUGH THIS AFTERNOON. IN
THE WESTERLY TO SOUTHWESTERLY LOW LEVEL WAA PATTERN...WOULD EXPECT
TO SEE SOME DECENT EROSION/DISSIPATION OF THE LOWER CLOUDS
THROUGH LATE MORNING/EARLY AFTERNOON WHICH SHOULD EVENTUALLY ALLOW
FOR PARTLY SUNNY SKIES. WILL NUDGE DOWN HIGHS JUST A TAD...GENERALLY
RANGING FROM UPPER 70S EAST TO LOWER 80S WEST. THIS WOULD STILL
ALLOW US TO DESTABILIZE THROUGH THIS AFTERNOON WITH ML CAPES PUSHING
UP CLOSE TO 1000 J/KG. AS A RESULT...WILL GO AHEAD AND ALLOW FOR
SOME CHANCE POPS ACROSS MUCH OF THE AREA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE 00Z NAM/GFS AND CMC ARE ALL TRYING TO HINT AT SOME SORT OF
CONTINUING PCPN OR REDEVELOPMENT TONIGHT SOMEWHERE ACROSS OUR AREA
WHILE THE 00Z ECMWF IS DRY. IT DOES LOOK LIKE WE COULD BE ON THE
EDGE OF A SOUTHWEST TO NORTHEAST ORIENTED 925-850 MB LOW LEVEL
JET LATER TONIGHT AND THIS COULD SERVE AS A FOCUSING MECHANISM.
AS A RESULT..WILL HANG ON TO SOME LOWER END POPS...BUT CONFIDENCE
IS NOT ALL THAT HIGH.
A COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT. AHEAD OF
THIS...WE SHOULD WARM UP FAIRLY WELL THROUGH THE DAY WITH HIGHS
PUSHING UP INTO THE LOW TO MID 80S. THIS WILL ALLOW US TO
DESTABILIZE ONCE AGAIN WITH MLCAPES AGAIN UP CLOSE TO 1000 J/KG.
THIS SHOULD LEAD TO SOME SCATTERED PRE FRONTAL SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. BETTER LOW LEVEL CONVERGENCE JUST
AHEAD OF THE FRONT WILL PUSH INTO OUR NORTHWEST LATE FRIDAY
AFTERNOON AND THEN PROGRESS SOUTHEAST ACROSS OUR AREA THROUGH FRIDAY
EVENING. THIS WILL ALLOW FOR A MORE ORGANIZED LINE OF SHOWERS AND
THUNDERSTORMS. DEEP LAYER SHEAR IS NOT TERRIBLY STRONG INITIALLY WITH
THE PCPN FRIDAY AFTERNOON/FRIDAY EVENING...BUT THE 0-3 KM SHEAR
VALUES DO PUSH UP INTO THE 25 TO 30 KNOT RANGE. THIS MAY BE
ENOUGH TO SUPPORT SOME MARGINALLY SEVERE STORMS LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING....ESPECIALLY ACROSS OUR NORTHWEST.
AS THE FRONT PUSHES OFF TO THE SOUTHEAST...EXPECT PCPN TO TAPER
OFF FROM NORTHWEST TO SOUTHEAST DURING THE DAY ON SATURDAY.
HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD INTO THE AREA THROUGH
THE LATER PART OF THE WEEKEND. HIGHS ON SATURDAY WILL BE IN THE 70-75
DEGREE RANGE WITH HIGHS ON SUNDAY IN THE UPPER 60S TO NEAR 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. COULD SEE
ENOUGH MOISTURE FROM THE LOW MOVING UP THE COAST TO PRODUCE
ISOLATED SHOWERS IN THE EXTREME EAST. AFTER MONDAY...SURFACE HIGH
PRESSURE EXTENDING INTO THE REGION FROM THE NE WILL BRING DRY
WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
SLIGHTLY UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE
NEXT SEVERAL DAYS. MOISTURE CONTINUES TO INCREASE OVER THE OHIO
VALLEY...RESULTING IN INCREASING CLOUDS...AND SHOWERS.
THE BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR STRATUS
DEVELOPMENT. THERE IS HIGH CONFIDENCE IN A THICKENING OF THE LOW-
LEVEL MOISTURE OVERNIGHT...WITH UPSTREAM CONDITIONS ALREADY
INDICATING MVFR CEILINGS ACROSS MUCH OF KENTUCKY AND IFR CIGS
ACROSS MUCH OF THE EASTERN HALF OF OHIO. THESE CLOUDS ARE EXPECTED
TO LOWER AS THEY OVERSPREAD THE TAF SITES. THIS WILL MAKE THE FOG
FORECAST SOMEWHAT MORE DIFFICULT BECAUSE THE STRATUS SHOULD KEEP
THE VSBYS FROM LOWERING TO LIFR MOST AREAS. BOTTOM LINE IS THAT A
BLANKET OF IFR CONDITIONS ARE EXPECTED TO DEVELOP ACROSS THE
ENTIRE FORECAST AREA OVER THE NEXT FEW HOURS. CEILINGS WILL BE SLOW
TO LIFT ON THURSDAY...AS SHOWERS AND LARGE PATCHES OF LATE RAIN
OVER SPREAD THE AREA AFTER 09Z ASSOCIATED WITH A SMALL
THUNDERSTORM COMPLEX OVER NORTHERN INDIANA MOVING TOWARDS THE
SOUTHEAST. WHILE THERE IS A RISK OF THUNDER AS THE PRECIPITATION
MOVES IN THIS MORNING...IT IS NOT HIGH ENOUGH TO PUT INTO THE
FORECAST AT THIS TIME. SHOWERS AND LOW CLOUDS WITH MVFR
CONDITIONS ARE EXPECTED TO LAST INTO THE MID AFTERNOON HOURS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...PARKER
AVIATION...HATZOS/HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
118 AM EDT THU SEP 19 2013
.SYNOPSIS...
AN INCREASE IN MOISTURE AND A SERIES OF WEAK UPPER LEVEL
DISTURBANCES WILL RESULT IN A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS
TO THE REGION TONIGHT AND THURSDAY. A BETTER CHANCE OF THUNDERSTORMS
WILL DEVELOP FRIDAY AFTERNOON INTO FRIDAY NIGHT AS A COLD FRONT
MOVES ACROSS THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THERE ARE CONCERNS ON BOTH SIDES OF THE CWA TONIGHT...REQUIRING A
FEW CHANGES TO THE GRIDS.
IN THE EASTERN CWA...A LARGE EXPANSE OF STRATUS HAS DEVELOPED. AS
ADDITIONAL MOISTURE MOVES NORTH INTO THE CWA...THIS IS EXPECTED TO
CONTINUE THROUGH THE NIGHT...WITH CEILINGS LOWERING. SKY GRIDS
HAVE BEEN ADJUSTED...THOUGH IT WAS NOT QUITE POSSIBLE TO INCREASE
TO 100 PERCENT WHEN MOST OF THE CWA STILL IS MOSTLY CLEAR...OR
EVEN BROKEN ON THE EDGES OF THE STRATUS. HOWEVER...THE FAR EASTERN
CWA SHOULD REMAIN CLOUDY THROUGH THE NIGHT.
ATTENTION IS ALSO TURNING TO CONVECTION NEAR CHICAGO...WHICH
SEVERAL RUNS OF THE HRRR AND RAP INDICATE WILL MAKE IT INTO THE
NORTHWEST CWA BY THE EARLY MORNING HOURS. THERE IS A GRADIENT OF
ELEVATED INSTABILITY THAT WILL SHIFT GRADUALLY EAST THROUGH THE
NIGHT...ALLOWING A TRAJECTORY (IF THE CONVECTION HOLDS TOGETHER)
THAT WOULD EVENTUALLY MOVE THROUGH INDIANA AND INTO THE ILN
FORECAST AREA. POPS HAVE BEEN INCREASED IN THE NORTHWESTERN CWA
WITH THUNDER INTRODUCED. TIMING THE CONVECTION OUT WOULD HAVE IT
INTO THE MERCER/WAYNE COUNTY AREAS BY 07Z...AND FURTHER FORECAST
UPDATES WILL BE NECESSARY IF THIS LOOKS MORE LIKELY TO OCCUR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
ISENTROPIC LIFT DEVELOPS ACROSS THE AREA THURSDAY WITH WARM FRONT
LIFTING NORTHEAST INTO THE GREAT LAKES. WILL CONTINUE CHANCE POPS
WITH THE BEST THREAT ACRS THE NW WHERE MOST FAVORABLE INSTBY WILL
EXIST. IN WARM AIR ADVECTION PATTERN EXPECT TEMPERATURES TO RUN
AROUND 5 DEGREES ABOVE NORMAL...WITH HIGHS RANGING FROM NEAR 80 NE
TO THE MID 80S SW.
WITH THE PASSAGE OF THE WARM FRONT AND RIDGING IN MID LEVELS THERE
WILL BE A LACK OF SIGNIFICANT FORCING THURSDAY NIGHT. HAVE DIMINISHED
POPS FROM THE SOUTH WITH A SLIGHT CHANCE EARLY TO DRY OVERNIGHT.
SRLY SFC WINDS WILL STAY UP AT 5 TO 10 MPH ALONG WITH CLOUD COVER
WILL KEEP TEMPERATURES ON THE WARMER SIDE. EXPECT OVERNIGHT LOWS
TO RANGE FROM THE MID 60S SE TO THE UPPER 60S NW.
PROGRESSIVE/DIGGING MID LEVEL TROF TO MOVE INTO THE WESTERN GREAT
LAKES/UPR MS VLY FRIDAY AND THE GREAT LAKES FRIDAY NIGHT.
ASSOCIATED SFC COLD FRONT TO PUSH EAST THRU ILN/S FA FRIDAY
NIGHT/EARLY SATURDAY. NAM SOLN IS DEPICTING A PRE-FRONTAL TROF
WITH MODERATE INSTBY INTO THE WEST LATE FRIDAY AFTN. GIVEN THE
HIGHER RESOLUTION THIS LOOKS REASONABLE. WILL CONTINUE TO RAMP UP
POPS TO LKLY LATE IN THE DAY FRIDAY AND THEN CATEGORICAL FRIDAY
NIGHT ACRS THE ENTIRE REGION AS THE FRONT PUSHES IN. WILL CONTINUE
TO HIGHLIGHT POTENTIAL FOR LOCALLY DAMAGING WINDS AND SOME HAIL
WITH SOME OF THE STRONGER STORMS FRIDAY AFTN/EARLY EVENING. THIS
WILL BE DEPENDENT ON INSTBY AND WILL LIMIT AREAL EXTENT TO OVER
THE WESTERN COUNTIES. GIVEN WAA AHEAD OF THE FRONT...EXPECT TEMPS
TO BE CLOSE TO 10 DEGREES ABOVE NORMAL WITH HIGHS ON FRIDAY
RANGING FROM THE MID/UPR 80S SE TO THE LOWER 80S FAR NW.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT IS EXPECTED TO BE LOCATED THROUGH THE EASTERN PARTS OF
THE FA SATURDAY MORNING. SHOWERS AND SOME THUNDERSTORMS WILL LINGER
BEHIND THE FRONT ON SATURDAY AS THE UPPER TROUGH SWINGS THROUGH THE
OHIO RIVER VALLEY REGION. WIDELY SCATTERED SHOWERS MAY LINGER IN THE
SE ON SUNDAY. LATEST ECMWF IS MORE PROGRESSIVE WITH THE FRONT AND
FUTURE FORECASTS MAY NEED TO CUT BACK ON PRECIPITATION SATURDAY
AFTERNOON AND SUNDAY. ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM
THE NORTH. COULD SEE ENOUGH MOISTURE FROM THE LOW MOVING UP THE
COAST TO PRODUCE ISOLATED SHOWERS IN THE EXTREME EAST. AFTER
MONDAY...SURFACE HIGH PRESSURE EXTENDING INTO THE REGION FROM THE
NE WILL BRING DRY WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SLIGHTLY UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE
NEXT SEVERAL DAYS. MOISTURE CONTINUES TO INCREASE OVER THE OHIO
VALLEY...RESULTING IN INCREASING CLOUDS...AND SHOWERS.
THE BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR STRATUS
DEVELOPMENT. THERE IS HIGH CONFIDENCE IN A THICKENING OF THE LOW-
LEVEL MOISTURE OVERNIGHT...WITH UPSTREAM CONDITIONS ALREADY
INDICATING MVFR CEILINGS ACROSS MUCH OF KENTUCKY AND IFR CIGS
ACROSS MUCH OF THE EASTERN HALF OF OHIO. THESE CLOUDS ARE EXPECTED
TO LOWER AS THEY OVERSPREAD THE TAF SITES. THIS WILL MAKE THE FOG
FORECAST SOMEWHAT MORE DIFFICULT BECAUSE THE STRATUS SHOULD KEEP
THE VSBYS FROM LOWERING TO LIFR MOST AREAS. BOTTOM LINE IS THAT A
BLANKET OF IFR CONDITIONS ARE EXPECTED TO DEVELOP ACROSS THE
ENTIRE FORECAST AREA OVER THE NEXT FEW HOURS. CEILINGS WILL BE SLOW
TO LIFT ON THURSDAY...AS SHOWERS AND LARGE PATCHES OF LATE RAIN
OVER SPREAD THE AREA AFTER 09Z ASSOCIATED WITH A SMALL
THUNDERSTORM COMPLEX OVER NORTHERN INDIANA MOVING TOWARDS THE
SOUTHEAST. WHILE THERE IS A RISK OF THUNDER AS THE PRECIPITATION
MOVES IN THIS MORNING...IT IS NOT HIGH ENOUGH TO PUT INTO THE
FORECAST AT THIS TIME. SHOWERS AND LOW CLOUDS WITH MVFR
CONDITIONS ARE EXPECTED TO LAST INTO THE MID AFTERNOON HOURS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS
SHORT TERM...AR
LONG TERM...PARKER
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
607 AM EDT THU SEP 19 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER EASTERN PENNSYLVANIA TODAY WILL SLIDE
OFF THE EAST COAST FRIDAY. A COLD FRONT WILL PUSH EAST ACROSS THE
STATE SATURDAY AND SATURDAY NIGHT. ANOTHER SLOW MOVING HIGH
PRESSURE SYSTEM WILL THEN BUILD INTO THE REGION SUNDAY AND REMAIN
OVER THE AREA THROUGH MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SATELLITE SHOWS AN EXPANDING AREA OF STRATOCU ACROSS WESTERN PA
EARLY THIS AM...THE RESULT OF COOLING/MOISTENING BLYR BENEATH A
STRONG SUBSIDENCE INVERSION. SATL TRENDS SUGGEST ROUGHLY THE
WESTERN HALF OF THE STATE WILL BE COVERED BY THIS DECK OF LOW
CLOUDS BY 12Z. WHERE SKIES HAVE REMAINED CLEAR...MODIS 11-3.7UM
IMAGERY SHOWS FOG HAS DEVELOPED IN THE VALLEYS OF NORTH CENTRAL
PA.
THE PATCHY FOG ACROSS THE EASTERN HALF OF THE STATE SHOULD BURN
OFF BY ARND 13Z BASED ON LATEST 3KM HRRR SFC RH. FURTHER WEST...ARRIVAL
OF MUCH HIGHER DWPTS WILL RESULT IN ONLY SLOW CLEARING FROM EARLY
AM STRATOCU. EXPECT THE LOWS CLOUDS TO LIFT AND BREAK UP TO A BKN
CU FIELD BY AFTN ACROSS THE W MTNS.
GEFS MEAN 925MB TEMPS SUPPORT MAX TEMPS THIS AFTN IN THE L/M70S...WITH
THE WARMEST TEMPS RELATIVE TO NORMAL ACROSS THE W MTNS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
A MAINLY CLEAR SKY AND LIGHT WINDS SHOULD LEAD TO PATCHY VALLEY
FOG LATE TONIGHT. INCREASING LOW LVL MOISTURE ON A LIGHT SOUTHERLY
FLOW SHOULD LEAD TO A MILDER NIGHT WITH MINS FROM THE U40S TO L50S
MOST LOCATIONS.
AN INCREASING SSW FLOW AHEAD OF SHORTWAVE DIVING INTO THE GRT LKS
WILL PUSH PWATS AND 8H TEMPS WELL ABV SEASONAL NORMS ACROSS
WESTERN PA FRIDAY. DIURNAL HEATING OF THIS AIR MASS SHOULD RESULT IN
MARGINAL INSTABILITY ACROSS THE W MTNS BY LATE IN THE
DAY...POSSIBLY SUPPORTING DEVELOPMENT OF A FEW PM TSRA ACROSS THE
ALLEGHENY PLATEAU. SKIES SHOULD RANGE FROM PTSUNNY ACROSS THE W
MTNS...TO SUNNY E OF THE SUSQ RIVER...WHERE LOWER PWAT AIR WILL
LINGER. GEFS MEAN 925 TEMPS RISE ABOUT 2C FROM THOSE OF TDY...SUPPORTING
MAX TEMPS BTWN 75-80F.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FAIRLY MINOR TIMING DIFFS WITH RESPECT TO FROPA SAT/SAT NIGHT.
LATEST GEFS/SREF AND OPER RUNS SUPPORT RAINFALL BTWN 0.5 AND ONE
INCH OVR MUCH OF THE AREA WITH LOCALLY HIGHER AMTS POSS...AS PLUME
OF ANOMALOUS PWATS WITH GULF OF MEX CONNECTION WORKS ACROSS THE
AREA AHEAD OF CDFRONT. ABUNDANT PRE-FRONTAL CLOUD COVER INDICATED
BY MDL 850-500RH FIELDS AND THIS IS REFLECTED BY PRETTY MEAGER
CAPES SAT AFTN...BUT WILL MAINTAIN SLIGHT CHC OF TSRA FOR NOW.
BY SUNDAY...A MORE PROGRESSIVE UPPER AIR PATTERN IS NOW INDICATED
THAN A DAY AGO...WITH BULK OF MDL DATA PUSHING CDFRONT EAST OF THE
REGION BY EARLY SUNDAY. HAVE TRIMMED POPS BUT KEPT SLIGHT CHC IN
THE FCST FOR SUNDAY TO ACCOUNT FOR HANDFUL OF GEFS MEMBERS WHICH
STILL DEVELOP WAVE ON FRONT AND KEEP SHRA GOING ACROSS EASTERN PA
SUNDAY.
A TRANQUIL WX PATTERN APPEARS TO BE IN STORE FOR CENTRAL PA NEXT
WEEK...AS NEARLY ALL MED RANGE MDL DATA KEEP CENTRAL PA UNDER THE
INFLUENCE OF HIGH PRES AND DRY NORTHERLY FLOW. 925-850MB TEMPS
INDICATE DAYTIME TEMPS SHOULD BE CLOSE TO NORMAL FOR LATE
SEPT...ALTHOUGH SOME COOL NIGHTS APPEAR LIKELY DUE TO DRY AIR AND
PROXIMITY OF SFC HIGH.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
LIGHT SOUTHERLY FLOW PUSHING AN AREA OF INCREASED LOW LEVEL
MOISTURE NORTHWARD ACROSS W PA. AN AREA OF MVFR CIGS ASSOCIATED
WITH THIS FEATURE WILL WORK INTO KJST-KAOO-KFIG-KBFD DURING THE
PREDAWN HOURS...WITH CIGS DIPPING TO IFR AT KJST FOR A FEW HOURS
BEFORE SUNRISE IN UPSLOPE FLOW. ELSEWHERE...VFR CONDITIONS WILL
CONTINUE EXCEPT FOR LOCALIZED VALLEY FOG.
LOWER CIGS ACROSS PORTIONS OF THE WEST WILL IMPROVE TO VFR SHORTLY
AFTER SUNRISE AS LAYER MIXES...LEAVING A VFR DAY AREAWIDE.
CIG RESTRICTIONS AGAIN LIKELY EARLY FRI MORNING ACROSS THE WEST AS
INCREASING LOW LEVEL SOUTHWEST FLOW CONTINUES MOISTURE TRANSPORT
INTO THE REGION.
OUTLOOK...
FRI...PATCHY AM FOG POSS. OCNL MVFR CIGS ALSO POSS AT KJST-KBFD
IN SCT SHRA/TSRA DURING THE DAY. ELSEWHERE...MAINLY VFR.
FRI NIGHT...PATCHY FOG. LOWERING CIGS ACROSS THE WEST WITH SHOWERS
DEVELOPING AS COLD FRONT APPROACHES.
SAT-SAT NIGHT...COLD FRONT CROSSES REGION. RAIN AND SCT TSTMS WILL
BRING RESTRICTIONS AREAWIDE.
SUN...MVFR CONTINUES IN SCT SHRA/TSRA...ESP SE.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
327 PM CDT THU SEP 19 2013
.DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER/WSR-88D VAD
WIND PROFILE TRENDS STILL PLACE AN UPPER LEVEL RIDGE AXIS OVER THE
SOUTHEAST UNITED STATES THIS AFTERNOON. THIS IS RESULTING IN
ACROSS THE MID SOUTH WITH ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY THUS FAR LIMITED TO PORTIONS OF
CENTRAL/NORTH CENTRAL ARKANSAS AND SOUTH CENTRAL/SOUTHEAST
MISSOURI. TEMPERATURES AS OF 3 PM CDT ARE IN THE MIDDLE TO UPPER
80S AT MOST LOCATIONS. SHOWER AND THUNDERSTORM CHANCES ASSOCIATED
WITH AN APPROACHING COLD FRONT IS THE MAIN FORECAST CHALLENGE IN
THIS AFTERNOON/S FORECAST.
SHORT TERM MODELS INCLUDING THE 3KM HRRR INDICATE SHOWERS AND
THUNDERSTORMS LOCATED OVER PORTIONS OF ARKANSAS AND SOUTHERN
MISSOURI WILL WEAKEN AND DIMINISH WITH THE LOSS OF DAYTIME HEATING
THIS EVENING. THERE IS A POSSIBILITY THAT SOME OF THIS ACTIVITY
MAY REACH AREAS WEST OF THE MISSISSIPPI RIVER THIS EVENING AND
LEFT ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST. HOWEVER...THINK
BETTER SHOWER/THUNDERSTORM CHANCES WILL HOLD OFF UNTIL LATER
TONIGHT AS THE RIDGE MOVES FURTHER EAST AND MID LEVEL HEIGHT FALLS
WEAKEN SLIGHTLY.
A COLD FRONT CURRENTLY LOCATED OVER THE UPPER MIDWEST AND CENTRAL
PLAINS THIS AFTERNOON WILL DROP INTO THE LOWER MISSISSIPPI VALLEY
ON FRIDAY. MODEST MID LEVEL HEIGHT FALLS AND INSTABILITY WILL
ALLOW FOR SHOWERS AND THUNDERSTORMS TO OVERSPREAD THE MID SOUTH
MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER FRIDAY MORNING AND
SPREAD EAST TO THE REMAINDER OF THE FORECAST AREA FRIDAY AFTERNOON
INTO FRIDAY NIGHT.
NOT OVERLY IMPRESSED WITH STRONG/SEVERE THUNDERSTORM POTENTIAL AS
OVERALL SHEAR...INSTABILITY...AND FORCING WILL REMAIN ON THE WEAK
SIDE. LATER SHIFTS WILL MONITOR SHORT TERM TRENDS AND ADD STRONG
THUNDERSTORM MENTION IN THE HAZARDOUS WEATHER OUTLOOK IF
CONDITIONS BECOME MORE FAVORABLE AS THE FRONT APPROACHES. OVERALL
RAINFALL AMOUNTS THROUGH FRIDAY NIGHT MAY AVERAGE AROUND ONE HALF
INCH WITH LOCALIZED AMOUNTS UP TO PERHAPS 1.5-2 INCHES ALONG AND
WEST OF THE MISSISSIPPI RIVER...AND LESSER AMOUNTS TOWARDS THE
TENNESSEE RIVER. THE 12Z GFS HAS REMAINED ON THE QUICKER SIDE OF
MODEL SOLUTIONS TODAY AND LEANED FORECAST TOWARDS THE WRF/ECMWF
WHICH SUGGEST FRONTAL PASSAGE FRIDAY AFTERNOON/FRIDAY NIGHT.
LINGERING SHOWERS AND THUNDERSTORMS MAY PERSIST ON SATURDAY...ESPECIALLY
ACROSS NORTHEAST MISSISSIPPI AS THE FRONT SLOWS BEFORE DEPARTING
THE FORECAST AREA BY SATURDAY NIGHT. COOLER AND DRIER AIR WILL
FILTER IN BEHIND THE FRONT RESULTING IN A PERIOD OF MAINLY RAIN
FREE WEATHER ACROSS THE MID SOUTH THROUGH AT LEAST EARLY NEXT
WEEK AND TEMPERATURES AVERAGING NEAR NORMAL FOR SEPTEMBER. 12Z
GFS/ECMWF INDICATE SOME MODEL RUN TO RUN CONTINUITY ISSUES WITH
THE APPROACH OF AN UPPER LEVEL TROUGH OVER THE
PLAINS/MIDWEST...A BUILDING RIDGE OVER THE LOWER MISSISSIPPI
VALLEY AND THE POTENTIAL FOR WEAK SOUTHERLY LOW LEVEL RETURN FLOW
FROM THE GULF OF MEXICO PRODUCING SHOWERS AND THUNDERSTORMS. WILL
KEEP REMAINDER OF FORECAST NEXT WEEK DRY FOR NOW UNTIL MODELS
COME INTO BETTER AGREEMENT.
CJC
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. A FEW SHOWERS AND
THUNDERSTORMS MAY DEVELOP THIS AFTERNOON BUT COVERAGE IS NOT
EXPECTED TO BE ENOUGH TO INCLUDE IN TAFS. WILL AMEND AS NECESSARY
BASED ON RADAR TRENDS. WINDS WILL BE SOUTH AT 8-12 KTS...ONLY
DIMINISHING SLIGHTLY OVERNIGHT IN ADVANCE OF A COLD FRONT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE IN THE
FORECAST PERIOD. WILL LIKELY ADD PREVAILING SHOWERS IN LATER
UPDATES...WILL START WITH VCSH AT ALL SITES TOMORROW BETWEEN 10Z
AT JBR AND 16Z AT TUP. MEM AND MKL SHOULD SEE SHOWERS AROUND 14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 72 84 67 81 / 30 80 70 40
MKL 68 84 65 78 / 20 60 70 30
JBR 70 80 61 78 / 50 90 60 10
TUP 68 87 68 81 / 10 50 90 70
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
130 PM CDT THU SEP 19 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
THE MID-SOUTH WILL REMAIN IN THE WARM SECTOR AS A COLD FRONT
APPROACHES. THIS FRONT IS EXPECTED TO MOVE INTO MIDDLE TN LATE
FRIDAY NIGHT. THROUGH THIS PERIOD...LITTLE IMPACT WILL BE FELT
DESPITE MOISTURE SLOWLY INCREASING. STRATA CU ABV 3KFT TODAY
WILL DISSIPATED AFTER SUNSET BUT POSSIBLY RETURN TOWARD SUNRISE
CKV/BNA. SOME EARLY MORNING LIGHT FOG MAY DEVELOP CSV AS WELL.
OVERALL...VFR CONDITIONS WILL DOMINATE THE PERIOD. SOUTH WIND
TODAY MAY BRIEFLY GO ABV 10KNTS.
&&
.PREV DISCUSSION... /ISSUED 851 AM CDT THU SEP 19 2013/
UPDATE...
WARM FRONT WILL CONTINUE TO LIFT NORTHWARD AND AWAY FROM TN TODAY.
MEANWHILE...SFC HIGH WILL ALSO CONTINUE TO MOVE EAST TOWARD THE
ATLANTIC COAST. NO APPRECIABLE UPPER DYNAMICS ARE APPARENT AS THE
UPPER RIDGE AXIS WILL ACTUALLY BE IN CLOSER PROXIMITY TO THE MID
STATE BY LATE THIS AFTERNOON. HOWEVER...SOME WEAK BUT FAVORABLE
CURVATURE AND SHEAR WILL ROTATE ACROSS PORTIONS OF THE AXIS LATER
TODAY. THIS ALL TRANSLATES INTO A SLIGHT CHANCE OF SHOWERS OR
TSTMS ACROSS NORTHERN AREAS.
TEMPERATURES SHOULD BE A FEW DEGREES GREATER THAN YESTERDAY.
THUS...UPPER 80S FOR HIGHS STILL LOOKS REASONABLE. HRRR IN LINE
WITH CURRENT FCST THINKING.
ONLY MOD WILL BE TO RERUN ZONES WHICH WILL AUTOMATICALLY REMOVE
THE PATCHY FOG WORDING.
PREV DISCUSSION... /ISSUED 614 AM CDT THU SEP 19 2013/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THIS
PERIOD...THE ONLY EXCEPTION WILL BE SOME POSSIBLE EARLY MORNING
MVFR FOG. SURFACE HIGH PRESSURE ALONG THE EAST COAST WILL PRODUCE
A SOUTH FLOW INTO MID TN WITH SCT-BKN CLOUDS. A STRAY SHRA/TSRA
CANNOT BE RULED OUT...BUT PROB TOO LOW TO INCUDE IN TAFS.
13
PREV DISCUSSION... /ISSUED 355 AM CDT THU SEP 19 2013/
DISCUSSION...
FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION
COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED.
FORECAST QUANDARIES...PATCHY FOG POTENTIAL THRU THE MID MORNING
HRS TODAY...SHWR/TSTM CHANCES ESPECIALLY IN ASSOCIATION WITH FRONTAL
PASSAGE FRI NIGHT INTO SAT ALONG WITH POTENTIAL OF THIS BRINGING
HEAVY RAINFALL TO THE MID STATE...OVERALL WX PATTERN SAT NIGHT INTO
THE FIRST PART OF NEXT WEEK...AND TEMPS.
WITH MOST OF THE MID STATE EXPERIENCING CLR SKIES THIS MORNING...AND WITH
TEMPS/DEWPOINTS MAINLY IN THE LOW TO MID 60S ALONG WITH CALM WINDS...DO
EXPECT SOME PATCHY FOG TO FORM IN THE USUAL FOG PRONE LOCATIONS AND NEAR
BODIES OF WATER AND LAST THRU THE MID MORNING HRS. OTHERWISE...WITH RIDGING
INFLUENCES STILL DEPICTED BY MODEL CONSENSUS TO BECOME A LITTLE BIT MORE
ENHANCED THRU THE MORNING HRS ON FRI...WILL ONLY INTRODUCE A SLIGHT CHANCE
OF SHWRS LATE MORNING WITH A SLIGHT CHANCE OF SHWRS/TSTMS BY THE AFTERNOON
HRS WITH AFTERNOON HIGH TEMPS BEING AROUND 5 DEGREES OR SO ABOVE SEASONABLE
NORMAL VALUES UNDER PTCLDY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S...
LOWER 80S PLATEAU. WILL KEEP THE MID STATE DRY TONIGHT AGAIN UNDER PTCDLY
SKIES WITH THE POSSIBILITY OF YET AGAIN PATCHY FOG ACROSS USUAL FOG PRONE
LOCATIONS AND NEAR BODIES OF WATER THRU THE EARLY MORNING HRS...WITH A
SLIGHT CHANCE OF SHWRS/TSTMS ACROSS WRN PORTIONS OF THE MID STATE THRU THE
MID FRI MORNING HRS WITH THAT PATCHY FOG CONTINUING ACROSS CNTRL AND ERN
PORTIONS OF THE MID STATE DURING THIS TIME PERIOD ALSO. LOWS TONIGHT
ARE EXPECTED TO BE IN THE LOW TO MID 60S...AROUND 60 PLATEAU.
STILL LOOKS LIKE A PRONOUNCED UPPER LEVEL TROUGH WILL DEVELOP TO OUR W IN
ASSOCIATION WITH A SFC COLD FRONT...WITH THEN BOTH APPROACH FRI NIGHT AND
THEN MOVE ACROSS THE MID STATE AS THE DAY PROGRESSES ON SAT. GFS SHOWING
A LITTLE BIT MORE ENHANCED LOW LEVEL JET DYNAMICS MAINLY ACROSS SRN AND
ERN/PLATEAU PORTIONS OF THE MID STATE BY SAT MORNING WITH PRECIP WATER
AMOUNTS APPROACHING AND EVEN SLIGHTLY OVER TWO INCHES. IN LOOKING AT OTHER
FORECAST SOUNDINGS...GFS THE MOST AGGRESSIVE HERE WITH PRECIP WATER VALUES
ALONG WITH THE ABOVE MENTIONED LOW LEVEL JET STRUCTURE AND THUS PRODUCING
SOME HIGH QPF VALUES FOR THE MID STATE FRI NIGHT INTO THE FIRST HALF OF SAT.
IN LOOKING AT LATEST WPC QPF FORECAST ALONG WITH THE OTHER MODELS...AM AT
THIS TIME INCLINED TO BE A LITTLE CONSERVATIVE HERE AS THIS SYSTEM IS NOT
EXPECTED TO BRING A SIGNIFICANT FORCING...INSTABILITY...OR TEMP AIRMASS
CONTRAST WITH IT...THUS WILL GO WITH SLIGHTLY LOWER QPF VALUES THRU THIS
TIME PERIOD. HOWEVER...CAN NOT RULE OUT THE HEAVY RAINFALL POTENTIAL...
BUT THINK AT THIS TIME THAT ANY TYPE OF FLOODING WOULD BE LOCALIZED AND
MINOR AT BEST PER HIGH FFG VALUES AND RAINFALL NOT HAVING BEEN RECEIVED
OVER WIDE AREAS DURING THE PAST FEW DAYS AND WHAT IS EXPECTED TO HAPPEN
UP UNTIL FRI NIGHT. HOWEVER...TO GIVE A HEADS UP POTENTIAL ON THIS HEAVY
RAINFALL POSSIBILITY...WILL GO AHEAD AND MENTION IN THE MORNING`S HWO
ISSUANCE. OTHERWISE...HAVE MENTIONED INCREASING CHANCES OF SHWR/TSTMS E TO
W AS THE DAY PROGRESSES ON FRI WITH THE ABOVE MENTIONED LIMITED INSTABILITY
KEEPING ONLY A CHANCE OF TSTMS THRU FRI NIGHT INTO SAT. HAVE INCREASED POPS
TO CAT MOST LOCATIONS AFTER MIDNIGHT FRI NIGHT...LIKELY S AND PLATEAU...AND
WILL CONTINUE THE TREND OF DECREASING CHANCES OF SHWRS/TSTMS W TO E AS THE
DAY PROGRESSES ON SAT. HIGHS ON FRI WILL CONTINUE THE TREND OF 5 DEGREES OR
SO ABOVE SEASONABLE NORMAL VALUES WITH LOWS FRI NIGHT MAINLY IN THE LOW TO
UPPER 60S...WITH HIGHS ON SAT...AS THE FRONT MOVES THRU ALONG WITH THE UPPER
LEVEL TROUGH...NEAR OR ACTUALLY BELOW SEASONABLE NORMAL VALUES WITH HIGHS
MAINLY IN THE MID TO UPPER 70S.
AS FOR SAT NIGHT INTO THE MID PORTION OF NEXT WEEK...THRU THE FIRST PART
OF NEXT WEEK...WILL TREND CLOSE TO CURRENT FORECAST REASONING WITH
A SLIGHT CHANCE TO CHANCE OF SHWRS ACROSS AT LEAST ERN AND PLATEAU COUNTIES
SAT NIGHT...BUT AM LEANING TOWARD KEEPING THE MID STATE DRY ON SUN WITH
RIDGING INFLUENCES BUILDING ACROSS THE MID STATE PROVIDING DRY CONDITIONS
AND A RETURN TOWARD TEMPS NEAR SEASONABLE NORMS. EVEN THOUGH THERE ARE
SOME TIMING DIFFERENCES IN MODELS...UNLIKE AT THIS TIME YESTERDAY...IT
DOES NOT LOOK LIKE ANY OF THE MODELS ARE ADVERTISING ANY TYPE OF CLOSED
UPPER LEVEL LOW DEVELOPMENT BEHIND THE ABOVE MENTIONED FRONTAL SYSTEM THAT
WOULD SUBSTANTIALLY AFFECT THE MID STATE. THE LATEST EURO DOES DEVELOP A
CLOSED LOW ACROSS CNTRL MS BY MON MORNING BUT MOVES IT WELL SOUTH OF THE
MID STATE AND THEN OPENS IT UP BY TUE...POSSIBLY BRINGING SOME WRAP AROUND
ADDITIONAL MOISTURE TO THE MID STATE DURING THE FIRST PART OF NEXT WEEK.
WITH THIS OVERALL...AND MORE LIKELY TO OCCUR...CHANGE IN CONSENSUS MODEL
SOLUTIONS...WILL GO CLOSE TO CURRENT FORECASTED WX CONDITIONS ACROSS THE
MID STATE DURING THIS TIME PERIOD.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1219 PM CDT THU SEP 19 2013
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1039 AM CDT THU SEP 19 2013/
DISCUSSION...12Z UPPER AIR ANALYSIS PLACES AN UPPER LEVEL RIDGE
AXIS OVER THE SOUTHEAST UNITED STATES THIS MORNING.
CONSEQUENTLY...RAIN FREE WEATHER IS OCCURRING ACROSS THE MID SOUTH
WITH ANY CONVECTIVE ACTIVITY OCCURRING THUS FAR OVER THE OHIO
VALLEY AND PORTIONS OF THE UPPER MID WEST AND NORTHERN/CENTRAL
PLAINS. AS OF 10 AM CDT...TEMPERATURES ARE IN THE UPPER 70S TO
AROUND 80 DEGREES AT MOST LOCATIONS.
LATEST SHORT TERM MODEL TRENDS INDICATE THE POTENTIAL FOR SOME
ISOLATED TO PERHAPS SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP
FROM DAYTIME HEATING ACROSS PORTIONS OF THE MID SOUTH...MAINLY
ALONG AND WEST OF THE MISSISSIPPI RIVER WHERE BETTER LOW LEVEL
MOISTURE RESIDES. AT THIS TIME...FEEL THE LATEST 3KM HRRR AND RUC
MAY BE HANDLING THE CONVECTIVE POTENTIAL THE BEST. WILL UPDATE
FORECAST TO ADJUST POPS ACCORDINGLY...AND MAKE ADJUSTMENTS TO
TEMPERATURES...CLOUD COVER AND ALL OTHER ELEMENTS AS NEEDED.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 709 AM CDT THU SEP 19 2013/
DISCUSSION...
UPDATED FOR 12Z AVIATION DISCUSSION
PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 19 2013/
SKIES ARE MOSTLY CLEAR ACROSS MUCH OF THE FORECAST AREA THIS
MORNING WITH TEMPERATURES RANGING FROM THE MID 60S TO MID 70S.
TODAY SHOULD BE FAIRLY SIMILAR TO YESTERDAY WITH SOME SCATTERED
THUNDERSTORMS FORMING MAINLY DURING THE AFTERNOON HOURS ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. TEMPERATURES WILL REMAIN QUITE
WARM AGAIN TODAY WITH HIGHS IN THE MID 80S TO AROUND 90 DEGREES.
BY TONIGHT...A COLD FRONT WILL BE MOVING THROUGH THE CENTRAL
PLAINS AND INTO SOUTHWEST MISSOURI. AHEAD OF THE FRONT SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP WITH SOME OF THIS ACTIVITY
REACHING MAINLY WESTERN SECTIONS OF THE FORECAST AREA. ON FRIDAY
THE COLD FRONT WILL START MOVING THROUGH ARKANSAS SO THE CHANCE OF
RAIN WILL INCREASE OVER THE FORECAST AREA WITH THE BEST CHANCE OF
THUNDERSTORMS WEST OF THE MISSISSIPPI RIVER.
THIS MODEL RUN SEEMS TO BRING THE COLD FRONT THROUGH THE FORECAST
AREA FASTER THAN PREVIOUS RUNS SO THAT THE FRONT WILL BE JUST
ABOUT OUT OF THE REGION BY SATURDAY MORNING. FRIDAY NIGHT SHOULD
BE QUITE WET AS THE FRONT MOVES THROUGH. ON SATURDAY RAIN CHANCES
WILL DIMINISH FROM NORTHWEST TO SOUTHEAST AS COOLER AND DRIER AIR
BEGIN TO MOVE IN. TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
COOLER THAN NORMAL WITH HIGHS AROUND 80 DEGREES EXPECTED FOR MUCH
OF THE FORECAST AREA.
BY SATURDAY NIGHT...THE EXTREME SOUTHEAST CORNER OF THE FORECAST
AREA IS THE ONLY AREA THAT MIGHT SEE AN ISOLATED SHOWER. BY SUNDAY
HIGH PRESSURE WILL IN CONTROL OF THE WEATHER FOR MUCH OF THE EASTERN
U.S. INCLUDING THE FORECAST AREA. THIS WILL MEAN ANOTHER PERIOD OF
DRY WEATHER FROM SUNDAY THROUGH WEDNESDAY. TEMPERATURES WILL
REMAIN SLIGHTLY BELOW NORMAL SUNDAY AND MONDAY BUT WINDS SHOULD
BEGIN TO SHIFT TO THE SOUTH BY TUESDAY ALLOWING FOR WARMER AIR TO
RETURN TO THE REGION WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
TUESDAY AND WEDNESDAY.
ARS
.AVIATION...18Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. A FEW SHOWERS AND
THUNDERSTORMS MAY DEVELOP THIS AFTERNOON BUT COVERAGE IS NOT
EXPECTED TO BE ENOUGH TO INCLUDE IN TAFS. WILL AMEND AS NECESSARY
BASED ON RADAR TRENDS. WINDS WILL BE SOUTH AT 8-12 KTS...ONLY
DIMINISHING SLIGHTLY OVERNIGHT IN ADVANCE OF A COLD FRONT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE IN THE
FORECAST PERIOD. WILL LIKELY ADD PREVAILING SHOWERS IN LATER
UPDATES...WILL START WITH VCSH AT ALL SITES TOMORROW BETWEEN 10Z
AT JBR AND 16Z AT TUP. MEM AND MKL SHOULD SEE SHOWERS AROUND 14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 91 72 85 68 / 20 30 80 70
MKL 90 68 85 64 / 20 20 60 70
JBR 92 71 82 63 / 20 30 90 50
TUP 90 68 88 70 / 10 10 50 80
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1039 AM CDT THU SEP 19 2013
.DISCUSSION...12Z UPPER AIR ANALYSIS PLACES AN UPPER LEVEL RIDGE
AXIS OVER THE SOUTHEAST UNITED STATES THIS MORNING.
CONSEQUENTLY...RAIN FREE WEATHER IS OCCURRING ACROSS THE MID SOUTH
WITH ANY CONVECTIVE ACTIVITY OCCURRING THUS FAR OVER THE OHIO
VALLEY AND PORTIONS OF THE UPPER MID WEST AND NORTHERN/CENTRAL
PLAINS. AS OF 10 AM CDT...TEMPERATURES ARE IN THE UPPER 70S TO
AROUND 80 DEGREES AT MOST LOCATIONS.
LATEST SHORT TERM MODEL TRENDS INDICATE THE POTENTIAL FOR SOME
ISOLATED TO PERHAPS SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP
FROM DAYTIME HEATING ACROSS PORTIONS OF THE MID SOUTH...MAINLY
ALONG AND WEST OF THE MISSISSIPPI RIVER WHERE BETTER LOW LEVEL
MOISTURE RESIDES. AT THIS TIME...FEEL THE LATEST 3KM HRRR AND RUC
MAY BE HANDLING THE CONVECTIVE POTENTIAL THE BEST. WILL UPDATE
FORECAST TO ADJUST POPS ACCORDINGLY...AND MAKE ADJUSTMENTS TO
TEMPERATURES...CLOUD COVER AND ALL OTHER ELEMENTS AS NEEDED.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
&&
.PREV DISCUSSION... /ISSUED 709 AM CDT THU SEP 19 2013/
DISCUSSION...
UPDATED FOR 12Z AVIATION DISCUSSION
PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 19 2013/
SKIES ARE MOSTLY CLEAR ACROSS MUCH OF THE FORECAST AREA THIS
MORNING WITH TEMPERATURES RANGING FROM THE MID 60S TO MID 70S.
TODAY SHOULD BE FAIRLY SIMILAR TO YESTERDAY WITH SOME SCATTERED
THUNDERSTORMS FORMING MAINLY DURING THE AFTERNOON HOURS ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. TEMPERATURES WILL REMAIN QUITE
WARM AGAIN TODAY WITH HIGHS IN THE MID 80S TO AROUND 90 DEGREES.
BY TONIGHT...A COLD FRONT WILL BE MOVING THROUGH THE CENTRAL
PLAINS AND INTO SOUTHWEST MISSOURI. AHEAD OF THE FRONT SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP WITH SOME OF THIS ACTIVITY
REACHING MAINLY WESTERN SECTIONS OF THE FORECAST AREA. ON FRIDAY
THE COLD FRONT WILL START MOVING THROUGH ARKANSAS SO THE CHANCE OF
RAIN WILL INCREASE OVER THE FORECAST AREA WITH THE BEST CHANCE OF
THUNDERSTORMS WEST OF THE MISSISSIPPI RIVER.
THIS MODEL RUN SEEMS TO BRING THE COLD FRONT THROUGH THE FORECAST
AREA FASTER THAN PREVIOUS RUNS SO THAT THE FRONT WILL BE JUST
ABOUT OUT OF THE REGION BY SATURDAY MORNING. FRIDAY NIGHT SHOULD
BE QUITE WET AS THE FRONT MOVES THROUGH. ON SATURDAY RAIN CHANCES
WILL DIMINISH FROM NORTHWEST TO SOUTHEAST AS COOLER AND DRIER AIR
BEGIN TO MOVE IN. TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
COOLER THAN NORMAL WITH HIGHS AROUND 80 DEGREES EXPECTED FOR MUCH
OF THE FORECAST AREA.
BY SATURDAY NIGHT...THE EXTREME SOUTHEAST CORNER OF THE FORECAST
AREA IS THE ONLY AREA THAT MIGHT SEE AN ISOLATED SHOWER. BY SUNDAY
HIGH PRESSURE WILL IN CONTROL OF THE WEATHER FOR MUCH OF THE EASTERN
U.S. INCLUDING THE FORECAST AREA. THIS WILL MEAN ANOTHER PERIOD OF
DRY WEATHER FROM SUNDAY THROUGH WEDNESDAY. TEMPERATURES WILL
REMAIN SLIGHTLY BELOW NORMAL SUNDAY AND MONDAY BUT WINDS SHOULD
BEGIN TO SHIFT TO THE SOUTH BY TUESDAY ALLOWING FOR WARMER AIR TO
RETURN TO THE REGION WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
TUESDAY AND WEDNESDAY.
ARS
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. EXPECT A FEW SHRAS
AND TSRAS TO DEVELOP ACROSS NORTHERN SECTIONS THIS AFTN.
CONSIDERING THE LATEST INFO AND WHAT HAPPENED YESTERDAY NOT
CONFIDENT ENOUGH IN THE AMOUNT OF COVERAGE TO PLACE THE MENTION OF
VCTS AT ANY OF THE TAF SITES. WL INCLUDE A MENTION OF VCSH AT KJBR
AND KMKL. WINDS WILL BE SOUTH AT 8-12 KTS TODAY. TONIGHT...SHRAS
IN ADVANCE OF A COLD FRONT MAY BEGIN MOVING INTO KJBR BY THE END
OF THE PERIOD. WINDS OVERNIGHT WILL BE SOUTH AT 3-8 KTS.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 90 72 85 68 / 20 30 70 70
MKL 89 68 85 64 / 20 20 70 70
JBR 89 71 82 63 / 30 30 80 50
TUP 89 68 88 70 / 10 10 40 80
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
851 AM CDT THU SEP 19 2013
.UPDATE...
WARM FRONT WILL CONTINUE TO LIFT NORTHWARD AND AWAY FROM TN TODAY.
MEANWHILE...SFC HIGH WILL ALSO CONTINUE TO MOVE EAST TOWARD THE
ATLANTIC COAST. NO APPRECIABLE UPPER DYNAMICS ARE APPARENT AS THE
UPPER RIDGE AXIS WILL ACTUALLY BE IN CLOSER PROXIMITY TO THE MID
STATE BY LATE THIS AFTERNOON. HOWEVER...SOME WEAK BUT FAVORABLE
CURVATURE AND SHEAR WILL ROTATE ACROSS PORTIONS OF THE AXIS LATER
TODAY. THIS ALL TRANSLATES INTO A SLIGHT CHANCE OF SHOWERS OR
TSTMS ACROSS NORTHERN AREAS.
TEMPERATURES SHOULD BE A FEW DEGREES GREATER THAN YESTERDAY.
THUS...UPPER 80S FOR HIGHS STILL LOOKS REASONABLE. HRRR IN LINE
WITH CURRENT FCST THINKING.
ONLY MOD WILL BE TO RERUN ZONES WHICH WILL AUTOMATICALLY REMOVE
THE PATCHY FOG WORDING.
&&
.PREV DISCUSSION... /ISSUED 614 AM CDT THU SEP 19 2013/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THIS
PERIOD...THE ONLY EXCEPTION WILL BE SOME POSSIBLE EARLY MORNING
MVFR FOG. SURFACE HIGH PRESSURE ALONG THE EAST COAST WILL PRODUCE
A SOUTH FLOW INTO MID TN WITH SCT-BKN CLOUDS. A STRAY SHRA/TSRA
CANNOT BE RULED OUT...BUT PROB TOO LOW TO INCUDE IN TAFS.
13
PREV DISCUSSION... /ISSUED 355 AM CDT THU SEP 19 2013/
DISCUSSION...
FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION
COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED.
FORECAST QUANDARIES...PATCHY FOG POTENTIAL THRU THE MID MORNING
HRS TODAY...SHWR/TSTM CHANCES ESPECIALLY IN ASSOCIATION WITH FRONTAL
PASSAGE FRI NIGHT INTO SAT ALONG WITH POTENTIAL OF THIS BRINGING
HEAVY RAINFALL TO THE MID STATE...OVERALL WX PATTERN SAT NIGHT INTO
THE FIRST PART OF NEXT WEEK...AND TEMPS.
WITH MOST OF THE MID STATE EXPERIENCING CLR SKIES THIS MORNING...AND WITH
TEMPS/DEWPOINTS MAINLY IN THE LOW TO MID 60S ALONG WITH CALM WINDS...DO
EXPECT SOME PATCHY FOG TO FORM IN THE USUAL FOG PRONE LOCATIONS AND NEAR
BODIES OF WATER AND LAST THRU THE MID MORNING HRS. OTHERWISE...WITH RIDGING
INFLUENCES STILL DEPICTED BY MODEL CONSENSUS TO BECOME A LITTLE BIT MORE
ENHANCED THRU THE MORNING HRS ON FRI...WILL ONLY INTRODUCE A SLIGHT CHANCE
OF SHWRS LATE MORNING WITH A SLIGHT CHANCE OF SHWRS/TSTMS BY THE AFTERNOON
HRS WITH AFTERNOON HIGH TEMPS BEING AROUND 5 DEGREES OR SO ABOVE SEASONABLE
NORMAL VALUES UNDER PTCLDY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S...
LOWER 80S PLATEAU. WILL KEEP THE MID STATE DRY TONIGHT AGAIN UNDER PTCDLY
SKIES WITH THE POSSIBILITY OF YET AGAIN PATCHY FOG ACROSS USUAL FOG PRONE
LOCATIONS AND NEAR BODIES OF WATER THRU THE EARLY MORNING HRS...WITH A
SLIGHT CHANCE OF SHWRS/TSTMS ACROSS WRN PORTIONS OF THE MID STATE THRU THE
MID FRI MORNING HRS WITH THAT PATCHY FOG CONTINUING ACROSS CNTRL AND ERN
PORTIONS OF THE MID STATE DURING THIS TIME PERIOD ALSO. LOWS TONIGHT
ARE EXPECTED TO BE IN THE LOW TO MID 60S...AROUND 60 PLATEAU.
STILL LOOKS LIKE A PRONOUNCED UPPER LEVEL TROUGH WILL DEVELOP TO OUR W IN
ASSOCIATION WITH A SFC COLD FRONT...WITH THEN BOTH APPROACH FRI NIGHT AND
THEN MOVE ACROSS THE MID STATE AS THE DAY PROGRESSES ON SAT. GFS SHOWING
A LITTLE BIT MORE ENHANCED LOW LEVEL JET DYNAMICS MAINLY ACROSS SRN AND
ERN/PLATEAU PORTIONS OF THE MID STATE BY SAT MORNING WITH PRECIP WATER
AMOUNTS APPROACHING AND EVEN SLIGHTLY OVER TWO INCHES. IN LOOKING AT OTHER
FORECAST SOUNDINGS...GFS THE MOST AGGRESSIVE HERE WITH PRECIP WATER VALUES
ALONG WITH THE ABOVE MENTIONED LOW LEVEL JET STRUCTURE AND THUS PRODUCING
SOME HIGH QPF VALUES FOR THE MID STATE FRI NIGHT INTO THE FIRST HALF OF SAT.
IN LOOKING AT LATEST WPC QPF FORECAST ALONG WITH THE OTHER MODELS...AM AT
THIS TIME INCLINED TO BE A LITTLE CONSERVATIVE HERE AS THIS SYSTEM IS NOT
EXPECTED TO BRING A SIGNIFICANT FORCING...INSTABILITY...OR TEMP AIRMASS
CONTRAST WITH IT...THUS WILL GO WITH SLIGHTLY LOWER QPF VALUES THRU THIS
TIME PERIOD. HOWEVER...CAN NOT RULE OUT THE HEAVY RAINFALL POTENTIAL...
BUT THINK AT THIS TIME THAT ANY TYPE OF FLOODING WOULD BE LOCALIZED AND
MINOR AT BEST PER HIGH FFG VALUES AND RAINFALL NOT HAVING BEEN RECEIVED
OVER WIDE AREAS DURING THE PAST FEW DAYS AND WHAT IS EXPECTED TO HAPPEN
UP UNTIL FRI NIGHT. HOWEVER...TO GIVE A HEADS UP POTENTIAL ON THIS HEAVY
RAINFALL POSSIBILITY...WILL GO AHEAD AND MENTION IN THE MORNING`S HWO
ISSUANCE. OTHERWISE...HAVE MENTIONED INCREASING CHANCES OF SHWR/TSTMS E TO
W AS THE DAY PROGRESSES ON FRI WITH THE ABOVE MENTIONED LIMITED INSTABILITY
KEEPING ONLY A CHANCE OF TSTMS THRU FRI NIGHT INTO SAT. HAVE INCREASED POPS
TO CAT MOST LOCATIONS AFTER MIDNIGHT FRI NIGHT...LIKELY S AND PLATEAU...AND
WILL CONTINUE THE TREND OF DECREASING CHANCES OF SHWRS/TSTMS W TO E AS THE
DAY PROGRESSES ON SAT. HIGHS ON FRI WILL CONTINUE THE TREND OF 5 DEGREES OR
SO ABOVE SEASONABLE NORMAL VALUES WITH LOWS FRI NIGHT MAINLY IN THE LOW TO
UPPER 60S...WITH HIGHS ON SAT...AS THE FRONT MOVES THRU ALONG WITH THE UPPER
LEVEL TROUGH...NEAR OR ACTUALLY BELOW SEASONABLE NORMAL VALUES WITH HIGHS
MAINLY IN THE MID TO UPPER 70S.
AS FOR SAT NIGHT INTO THE MID PORTION OF NEXT WEEK...THRU THE FIRST PART
OF NEXT WEEK...WILL TREND CLOSE TO CURRENT FORECAST REASONING WITH
A SLIGHT CHANCE TO CHANCE OF SHWRS ACROSS AT LEAST ERN AND PLATEAU COUNTIES
SAT NIGHT...BUT AM LEANING TOWARD KEEPING THE MID STATE DRY ON SUN WITH
RIDGING INFLUENCES BUILDING ACROSS THE MID STATE PROVIDING DRY CONDITIONS
AND A RETURN TOWARD TEMPS NEAR SEASONABLE NORMS. EVEN THOUGH THERE ARE
SOME TIMING DIFFERENCES IN MODELS...UNLIKE AT THIS TIME YESTERDAY...IT
DOES NOT LOOK LIKE ANY OF THE MODELS ARE ADVERTISING ANY TYPE OF CLOSED
UPPER LEVEL LOW DEVELOPMENT BEHIND THE ABOVE MENTIONED FRONTAL SYSTEM THAT
WOULD SUBSTANTIALLY AFFECT THE MID STATE. THE LATEST EURO DOES DEVELOP A
CLOSED LOW ACROSS CNTRL MS BY MON MORNING BUT MOVES IT WELL SOUTH OF THE
MID STATE AND THEN OPENS IT UP BY TUE...POSSIBLY BRINGING SOME WRAP AROUND
ADDITIONAL MOISTURE TO THE MID STATE DURING THE FIRST PART OF NEXT WEEK.
WITH THIS OVERALL...AND MORE LIKELY TO OCCUR...CHANGE IN CONSENSUS MODEL
SOLUTIONS...WILL GO CLOSE TO CURRENT FORECASTED WX CONDITIONS ACROSS THE
MID STATE DURING THIS TIME PERIOD.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
940 PM CDT FRI SEP 20 2013
.UPDATE...
SOME WEAK LIFT WILL CONTINUE ACROSS THE SOUTHEASTERN HALF OF THE
CWA...BUT THE THREAT FOR HEAVY RAIN HAS ENDED. WILL KEEP THE
MENTION OF ISOLATED THUNDERSTORMS IN THE FAR SOUTH AND
SOUTHEAST THIS EVENING...WHERE THE MID-LEVEL TROUGH AXIS IS STILL
UPSTREAM. THE LIKELIHOOD OF DEEP CONVECTION WILL BE DIMINISHING
RAPIDLY AFTER MIDNIGHT.
THE 60-DEGREE ISODROSOTHERM IS STILL NORTHWEST OF THE CWA...BUT
WITH DEEP NORTHWESTERLY FLOW IN THE WAKE OF THE EXITING SYSTEM...
THE COLD FRONT SHOULD FINALLY HAVE THE THRUST NEEDED TO INVADE.
NOTICEABLY COOLER AND DRIER AIR WILL GREET MUCH OF NORTH TEXAS BY
DAYBREAK.
25
&&
.AVIATION...
/00Z TAFS/
CHALLENGES THIS EVENING WILL BE TIMING THE END OF LIGHT RAIN AND
TRANSITION FROM MVFR TO VFR CONDITIONS BY OR SHORTLY AFTER
MIDNIGHT.
THE MID LEVEL SHORTWAVE THAT HAS HELD UP THE TRUE COLD FRONT WELL
TO THE NORTHWEST OF THE AIRPORTS WAS SLOWLY MOVING EAST ACROSS
AREAS FROM KBKD TO KGLE AND THIS PROGRESS SHOULD CONTINUE
OVERNIGHT. THE TRUE COLD FRONT IS SHOWING SIGNS OF RESPONDING AND
SLOWLY MOVING SOUTHEAST AS WELL. NORTH FLOW AROUND 10 KTS WITH
WEAK LOW LEVEL ISENTROPIC ASCENT CONTINUING AHEAD OF THE FRONT
WILL KEEP MVFR CIGS IN AT DFW METRO AIRPORTS THROUGH AT LEAST
MIDNIGHT AND EVEN LATER AT WACO REGIONAL. THIS WILL KEEP MVFR
CONDITIONS IN AT ALL AIRPORTS ALL EVENING LONG.
MOS GUI DANCES ARE TRYING TO ADVERTISE BRIEF IFR AT WACO BETWEEN
MIDNIGHT-4 AM...BUT NOT BUYING INTO THIS AS BUFR AND RUC BAK40
SOUNDINGS INDICATE DRIER AIR ADVECTING IN AFTER MIDNIGHT AND WITH
NORTH FLOW AT LEAST 10 KTS...IFR IS UNLIKELY. ALL SITES SHOULD GO
VFR BETWEEN MIDNIGHT AND SUNRISE SATURDAY.
ONE CAVEAT HOWEVER. IF OUR SHORTWAVE PICKS UP FORWARD MOMENTUM...OR
SLOWS DOWN FOR ANY REASON...THEN TIMING OF TRENDS WILL BE ADJUSTED
ACCORDINGLY IN FUTURE AMENDMENTS AND ISSUANCES. NORTH FLOW 10-15 KTS
WILL VEER NORTHEAST AFTER SUNRISE SATURDAY MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT FRI SEP 20 2013/
AN UPPER LOW CURRENTLY CENTERED OVER THE WESTERN CONCHO VALLEY
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TONIGHT. THE LOW IS
ROTATING THROUGH THE BASE OF A LONG WAVE TROUGH WHICH EXTENDS FROM
WESTERN ONTARIO...THROUGH THE CENTRAL PLAINS...TO THE BIG BEND.
AS THE THE UPPER TROUGH AXIS MOVES EAST IT WILL ALLOW A COLD
FRONT...CURRENTLY LOCATED FROM NEAR A DUNCAN OKLAHOMA...WICHITA
FALLS...TO BIG SPRING LINE...TO MOVE SOUTH. THE PASSAGE OF THE
FRONT WILL BRING A SLOW AND STEADY DOSE OF DRIER AND COOLER AIR.
AHEAD OF THE FRONT...SHOWERS AND SOME THUNDERSTORMS WILL CONTINUE
THROUGH THE EVENING WITH THE HEAVIEST RAINFALL ACROSS THE
SOUTHERN/SOUTHEASTERN ZONES WHERE LARGE SCALE LIFT AND INSTABILITY
IS MOST ABUNDANT. WE WILL LEAVE THE CURRENT FLASH FLOOD WATCH IN
EFFECT FOR LOCATIONS SOUTH OF A LINE FROM GOLDTHWAITE TO HILLSBORO
TO ATHENS. SOME OF THESE AREAS HAVE ALREADY SEEN FLOODING OR AT
LEAST RAINFALL AMOUNTS IN EXCESS OF 4 INCHES AND AN ADDITIONAL 2
TO 3 INCHES OF RAIN IS POSSIBLE. WE EXPECT THE RAIN CHANCES TO
LINGER THROUGH SATURDAY ACROSS THE EXTREME SOUTHERN ZONES AS
RESIDUAL MOISTURE WRAPS AROUND THE DEPARTING UPPER LOW.
THE REMAINDER OF NORTH TEXAS SHOULD SEE DECREASING CLOUDS ON
SATURDAY WITH AFTERNOON HIGHS MAINLY IN THE LOWER AND MIDDLE 80S
AND A NORTH WIND IN THE 5 TO 15 MPH RANGE. A MOSTLY CLEAR SKY AND
LIGHT WIND SATURDAY NIGHT/SUNDAY MORNING WILL RESULT IN SOME
FAIRLY COOL TEMPERATURES WITH MORNING LOWS RANGING FROM THE MIDDLE
50S IN THE NORTH TO THE MIDDLE 60S IN THE SOUTH. SUNDAY HAS THE
MAKINGS OF A VERY PLEASANT DAY WITH A LIGHT WIND... ABUNDANT SUN
AND AFTERNOON HIGHS IN THE LOWER AND MIDDLE 80S.
THE UPPER PATTERN WILL REMAIN PROGRESSIVE THROUGH NEXT WEEK WITH
GENERALLY WEST TO SOUTHWEST FLOW ALOFT. THE GULF WILL REMAIN
CLOSED OFF THROUGH ABOUT MID WEEK. HOWEVER...LOW LEVEL MOISTURE
WILL BE ON THE INCREASE THE SECOND HALF OF THE WEEK AS AN UPPER
TROUGH AND ASSOCIATED SURFACE LOW DEVELOP IN THE WEST. THE UPPER
TROUGH IS PROGGED TO MOVE INTO THE CENTRAL PLAINS BY SATURDAY AND
ALLOW A COLD FRONT TO MOVE INTO THE REGION. THE PASSAGE OF THIS
SYSTEM MAY BRING ANOTHER CHANCE FOR RAIN TO NORTH TEXAS AROUND
SATURDAY OF NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 63 84 63 86 61 / 20 10 0 0 5
WACO, TX 66 81 59 84 61 / 40 10 0 0 5
PARIS, TX 61 81 58 81 57 / 20 10 0 0 5
DENTON, TX 59 84 56 86 59 / 10 5 0 0 5
MCKINNEY, TX 60 82 56 82 54 / 20 10 0 0 5
DALLAS, TX 63 83 64 85 63 / 20 10 0 0 5
TERRELL, TX 62 81 58 82 60 / 20 10 0 0 5
CORSICANA, TX 67 84 61 83 60 / 40 20 0 0 5
TEMPLE, TX 65 84 63 85 62 / 50 20 5 0 5
MINERAL WELLS, TX 58 83 57 85 60 / 10 5 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/25
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
657 PM CDT FRI SEP 20 2013
.AVIATION...
/00Z TAFS/
CHALLENGES THIS EVENING WILL BE TIMING THE END OF LIGHT RAIN AND
TRANSITION FROM MVFR TO VFR CONDITIONS BY OR SHORTLY AFTER
MIDNIGHT.
THE MID LEVEL SHORTWAVE THAT HAS HELP UP THE TRUE COLD FRONT WELL
TO THE NORTHWEST OF THE AIRPORTS WAS SLOWLY MOVING EAST ACROSS
AREAS FROM KBKD TO KGLE AND THIS PROGRESS SHOULD CONTINUE
OVERNIGHT. THE TRUE COLD FRONT IS SHOWING SIGNS OF RESPONDING AND
SLOWLY MOVING SOUTHEAST AS WELL. NORTH FLOW AROUND 10 KTS WITH
WEAK LOW LEVEL ISENTROPIC ASCENT CONTINUING AHEAD OF THE FRONT
WILL KEEP MVFR CIGS IN AT DFW METRO AIRPORTS THROUGH AT LEAST
MIDNIGHT AND EVENING LATER AT WACO REGIONAL. THIS WILL KEEP MVFR
CONDITIONS IN AT ALL AIRPORTS ALL EVENING LONG.
MOS GUIDANCES ARE TRYING TO ADVERTISE BRIEF IFR AT WACO BETWEEN
MIDNIGHT-4 AM...BUT NOT BUYING INTO THIS AS BUFR AND RUC BAK40
SOUNDINGS INDICATE DRIER AIR ADVECTING IN AFFTER MIDNIGTH AND WITH
NORTH FLOW AT LEAST 10 KTS...IFR IS UNLIKELY. ALL SITES SHOULD GO
VFR BETWEEN MIDNIGHT AND SUNRISE SATURDAY.
ONE CAVEAT HOWEVER. IF OUR SHORTWAVE PICKS UP FORWARD MOMENTUM...OR
SLOWS DOWN FOR ANY REASON...THEN TIMING OF TRENDS WILL BE ADJUSTED
ACCORDINGLY IN FUTURE AMENDMENTS AND ISSUANCES. NORTH FLOW 10-15 KTS
WILL VEER NORTHEAST AFTER SUNRISE SATURDAY MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT FRI SEP 20 2013/
AN UPPER LOW CURRENTLY CENTERED OVER THE WESTERN CONCHO VALLEY
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TONIGHT. THE LOW IS
ROTATING THROUGH THE BASE OF A LONG WAVE TROUGH WHICH EXTENDS FROM
WESTERN ONTARIO...THROUGH THE CENTRAL PLAINS...TO THE BIG BEND.
AS THE THE UPPER TROUGH AXIS MOVES EAST IT WILL ALLOW A COLD
FRONT...CURRENTLY LOCATED FROM NEAR A DUNCAN OKLAHOMA...WICHITA
FALLS...TO BIG SPRING LINE...TO MOVE SOUTH. THE PASSAGE OF THE
FRONT WILL BRING A SLOW AND STEADY DOSE OF DRIER AND COOLER AIR.
AHEAD OF THE FRONT...SHOWERS AND SOME THUNDERSTORMS WILL CONTINUE
THROUGH THE EVENING WITH THE HEAVIEST RAINFALL ACROSS THE
SOUTHERN/SOUTHEASTERN ZONES WHERE LARGE SCALE LIFT AND INSTABILITY
IS MOST ABUNDANT. WE WILL LEAVE THE CURRENT FLASH FLOOD WATCH IN
EFFECT FOR LOCATIONS SOUTH OF A LINE FROM GOLDTHWAITE TO HILLSBORO
TO ATHENS. SOME OF THESE AREAS HAVE ALREADY SEEN FLOODING OR AT
LEAST RAINFALL AMOUNTS IN EXCESS OF 4 INCHES AND AN ADDITIONAL 2
TO 3 INCHES OF RAIN IS POSSIBLE. WE EXPECT THE RAIN CHANCES TO
LINGER THROUGH SATURDAY ACROSS THE EXTREME SOUTHERN ZONES AS
RESIDUAL MOISTURE WRAPS AROUND THE DEPARTING UPPER LOW.
THE REMAINDER OF NORTH TEXAS SHOULD SEE DECREASING CLOUDS ON
SATURDAY WITH AFTERNOON HIGHS MAINLY IN THE LOWER AND MIDDLE 80S
AND A NORTH WIND IN THE 5 TO 15 MPH RANGE. A MOSTLY CLEAR SKY AND
LIGHT WIND SATURDAY NIGHT/SUNDAY MORNING WILL RESULT IN SOME
FAIRLY COOL TEMPERATURES WITH MORNING LOWS RANGING FROM THE MIDDLE
50S IN THE NORTH TO THE MIDDLE 60S IN THE SOUTH. SUNDAY HAS THE
MAKINGS OF A VERY PLEASANT DAY WITH A LIGHT WIND... ABUNDANT SUN
AND AFTERNOON HIGHS IN THE LOWER AND MIDDLE 80S.
THE UPPER PATTERN WILL REMAIN PROGRESSIVE THROUGH NEXT WEEK WITH
GENERALLY WEST TO SOUTHWEST FLOW ALOFT. THE GULF WILL REMAIN
CLOSED OFF THROUGH ABOUT MID WEEK. HOWEVER...LOW LEVEL MOISTURE
WILL BE ON THE INCREASE THE SECOND HALF OF THE WEEK AS AN UPPER
TROUGH AND ASSOCIATED SURFACE LOW DEVELOP IN THE WEST. THE UPPER
TROUGH IS PROGGED TO MOVE INTO THE CENTRAL PLAINS BY SATURDAY AND
ALLOW A COLD FRONT TO MOVE INTO THE REGION. THE PASSAGE OF THIS
SYSTEM MAY BRING ANOTHER CHANCE FOR RAIN TO NORTH TEXAS AROUND
SATURDAY OF NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 63 84 63 86 61 / 50 10 0 0 5
WACO, TX 66 81 59 84 61 / 70 10 0 0 5
PARIS, TX 61 81 58 81 57 / 50 10 0 0 5
DENTON, TX 59 84 56 86 59 / 50 5 0 0 5
MCKINNEY, TX 60 82 56 82 54 / 50 10 0 0 5
DALLAS, TX 63 83 64 85 63 / 50 10 0 0 5
TERRELL, TX 62 81 58 82 60 / 50 10 0 0 5
CORSICANA, TX 67 84 61 83 60 / 60 20 0 0 5
TEMPLE, TX 65 84 63 85 62 / 100 20 5 0 5
MINERAL WELLS, TX 58 83 57 85 60 / 40 5 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR TXZ135-142>148-
156>162-174-175.
&&
$$
05/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
619 AM CDT THU SEP 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT THU SEP 19 2013
MAIN FORECAST CONCERNS ARE ON SHOWERS AND THUNDERSTORMS TODAY INTO
TONIGHT WITH THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS
AFTERNOON AND EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH DIGGING INTO THE EASTERN
DAKOTAS AND CENTRAL PLAINS...PUSHING EAST TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY. SEVERAL WEAK EMBEDDED SHORTWAVES NOTED IN
SOUTHWEST FLOW OVER THE REGION THIS MORNING. SURFACE OBSERVATIONS
PLACED A COLD FRONT OVER THE EASTERN DAKOTAS MOVING EAST. SHOWERS
AND ISOLATED THUNDERSTORMS WERE OCCURRING EARLY THIS MORNING MAINLY
SOUTH OF INTERSTATE 90.
THE COLD FRONT WILL MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY
TODAY BRINGING SHOWERS AND THUNDERSTORMS TO THE AREA. MLCAPE VALUES
INCREASE TO 1500 TO 2200 J/KG THIS AFTERNOON AHEAD OF THE COLD
FRONT. 0-6 KM BULK SHEAR VALUES START OFF RATHER WEAK EARLY THIS
AFTERNOON AS THE UPPER TROUGH AND JET STREAK ARE LOCATED WELL
WELL WEST OF THE REGION. HOWEVER...THE TROUGH STARTS TO CATCH UP
TO THE COLD FRONT DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS. 0-6 KM SHEAR STARTS OUT IN THE 20 TO 25 KT RANGE EARLY THIS
AFTERNOON AND THEN INCREASES TO 30 TO 40 KTS DURING THE EARLY
EVENING HOURS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER
WHICH WOULD FAVOR A LINEAR CONVECTIVE MODE WITH POSSIBLE BOWING
SEGMENTS...CAPABLE OF PRODUCING DAMAGING WINDS. MESOSCALE MODELS
SUCH AS THE SPCWRF AND HIRESARW EAST ARE IN AGREEMENT WITH THIS
CONVECTIVE MODE. THE 0-3 KM SHEAR VECTOR IS INITIALLY ORIENTED
PERPENDICULAR TO THE FRONT BUT THEN TURNS MORE PARALLEL TO IT.
STORMS ALONG OR BEHIND THE FRONT COULD STRUGGLE TO ORGANIZE INTO
LINEAR STRUCTURES IF THEY DEVELOP BEHIND THE LEADING WIND SHIFT
OF THE FRONT. ALSO...CANNOT RULE OUT SOME MARGINALLY SEVERE HAIL
WITH THIS ACTIVITY GIVEN THE HIGHER CAPE VALUES. SHOWERS AND
STORMS WILL CONTINUE ACROSS MUCH OF THE AREA EARLY THIS EVENING
THEN GRADUALLY SHIFT SOUTHEAST LATE TONIGHT AS THE COLD FRONT
PROGRESSES EAST. SHOWERS AND THUNDERSTORMS WILL ALSO SHIFT
SOUTHEAST AND EXIT THE AREA LATE TONIGHT INTO FRIDAY MORNING. PLAN
ON AN UNSEASONABLY WARM DAY ACROSS THE AREA TODAY WITH WARM
SOUTHERLY FLOW. LOOK FOR HIGH TEMPERATURES TO CLIMB INTO THE THE
LOWER TO MID 80S BEFORE THE PRECIPITATION MOVES IN. CANNOT RULE
OUT SOME UPPER 80S OVER NORTHEAST IOWA INTO SOUTHWEST WISCONSIN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 AM CDT THU SEP 19 2013
THE UPPER LEVEL TROUGH SWINGS THROUGH THE FORECAST AREA ON FRIDAY
PRODUCING STRATUS AND SOME STRATOCUMULUS DURING THE AFTERNOON
HOURS...LEADING TO MOSTLY CLOUDY SKIES. FRIDAY WILL BE BREEZY WITH
A TIGHT PRESSURE GRADIENT OVER THE REGION AS HIGH PRESSURE BUILDS
IN FROM THE WEST. THE HIGH WILL THEN MOVE INTO THE AREA FRIDAY
NIGHT INTO SATURDAY MORNING WITH DRY AND QUIET WEATHER EXPECTED.
PLAN ON LOW TEMPERATURES FALLING INTO THE 40S FRIDAY NIGHT...WITH
SOME UPPER 30S POSSIBLE OVER FAVORED COLD SPOTS ACROSS CENTRAL
INTO NORTH CENTRAL WISCONSIN. THE HIGH WILL REMAIN OVER THE AREA
THROUGH THE WEEKEND. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE
60S...WITH OVERNIGHT LOWS FALLING INTO THE UPPER 30S TO LOWER 40S.
THE COLDEST TEMPERATURES WILL BE ACROSS CENTRAL AND NORTH CENTRAL
WISCONSIN WHERE SOME LOWER 30S ARE POSSIBLE. HAVE ADDED FROST TO
THE FORECAST ACROSS THESE AREAS LATE SATURDAY NIGHT INTO EARLY
SUNDAY MORNING. A FROST ADVISORY MAY BE NEEDED ALONG AND NORTH OF
THE INTERSTATE 94 CORRIDOR. THE HIGH WILL START TO SLIDE EAST OF
THE REGION SUNDAY INTO SUNDAY NIGHT AS A TROUGH DEVELOPS OVER THE
PLAINS. SOUTH/SOUTHEAST FLOW WILL SET UP OVER THE REGION USHERING
IN SLIGHTLY WARMER TEMPERATURES FOR SUNDAY. PLAN ON HIGHS IN THE
UPPER 60S TO LOWER 70S. THE NEXT CHANCE FOR RAIN WILL BE MONDAY
NIGHT INTO TUESDAY AS AN UPPER TROUGH SWINGS THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY FROM THE CENTRAL/NORTHERN PLAINS. SURFACE
HIGH PRESSURE LOOKS TO HOLD STRONG OVER THE AREA AND MUCH OF THE
PRECIPITATION THE FORECAST MODELS ARE SHOWING STARTS TO REALLY DRY
UP AS THE TROUGH MOVES INTO THE HIGH. SOUTHERLY FLOW LOOKS TO
CONTINUE OVER THE AREA THROUGH THE MIDDLE OF NEXT WEEK WITH MAINLY
QUIET WEATHER EXPECTED AND TEMPERATURES HOLDING NEAR NORMAL WITH
HIGHS IN THE 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 619 AM CDT THU SEP 19 2013
SCATTERED CONVECTION KEEPS POPPING UP AROUND THE AREA THIS
MORNING IN THE LOW LEVEL JET AND THE ISENTROPIC UP GLIDE OCCURRING
ON THE 305K AND 310K SURFACES. THE 19.09Z RAP SUGGESTS THIS
MOISTURE TRANSPORT AND ISENTROPIC UP GLIDE WILL START TO DIMINISH
AFTER SUNRISE AND EXPECT THAT THE ACTIVITY WILL ALSO START TO
WEAKEN AS THIS OCCURS. WILL INCLUDE A VCTS FOR BOTH SITES FOR A
COUPLE OF HOURS AS THE BEST COVERAGE IS OVER CENTRAL WISCONSIN.
FOCUS THEN TURNS TO THE INCOMING COLD FRONT FOR THE AFTERNOON. THE
19.06Z NAM INDICATES THE MAIN UPPER LEVEL TROUGH WILL STILL BE
BACK ACROSS THE DAKOTAS LATE THIS AFTERNOON BUT THAT THERE WILL BE
A LEAD SHORT WAVE TROUGH AHEAD OF THIS. THIS SHORT WAVE TROUGH WILL
BE COMING WITH THE COLD FRONT AND SHOULD HELP WIDESPREAD SHOWER
AND STORMS DEVELOP DURING THE AFTERNOON. THE 19.08Z ARX LAPS AND
19.07Z HRRR SUGGEST THE CONVECTION WILL START TO IMPACT BOTH SITES
BETWEEN 21Z AND 22Z AND SHOULD LAST FOR A COUPLE OF HOURS UNTIL
THE FRONT COMES THROUGH SWINGING THE WINDS AROUND TO THE NORTHWEST.
THE FORCING FROM THE MAIN SHORT WAVE TROUGH WILL BE BEST RIGHT
BEHIND THE FRONT SO EXPECTING A 2 TO 3 HOUR PERIOD OF SOME POST-
FRONTAL SHOWERS TO OCCUR WITH MVFR CEILINGS. ONCE THIS ACTIVITY
ENDS...DRIER AIR STARTS TO WORK IN TO ALLOW THE CEILINGS TO GO UP
TO VFR FOR THE REMAINDER OF THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1114 PM MDT FRI SEP 20 2013
.UPDATE...
ISSUED AT 616 PM MDT FRI SEP 20 2013
RAN A QUICK UPDATE TO REDUCE CLOUD COVER ACROSS THE STATE.
SCATTERED CLOUDS SHOULD HANG ON ALONG THE NEW MEXICO BORDER
THROUGH 10 PM...WITH CLEAR SKIES ELSEWHERE. ALSO ADDED THE MENTION
OF PATCHY FOG OVER THE SAN LUIS VALLEY LATE TONIGHT INTO SATURDAY
MORNING...BASED ON THE LATEST MODEL DATA AND BUFKIT SOUNDINGS. MOZLEY
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 331 PM MDT FRI SEP 20 2013
QUIET WEATHER OVER THE AREA TODAY BENEATH TRANSIENT UPPER RIDGE.
STRATUS HAS CLEARED OUT OF MOST OF THE SE PLAINS...THOUGH COOLER AIR
MASS OVER THE REGION HAS KEPT SE PLAINS CAPPED. STILL WAITING TO
SEE IF SUFFICIENT HEATING WILL OCCUR TO POP A THUNDERSTORM OR TWO
ALONG THE CREST OF THE SOUTHERN SANGRES...AND PERHAPS ACROSS THE
EASTERN SAN JUAN MOUNTAINS...BUT SO FAR CONVECTION HAS HAD A HARD
TIME GETTING GOING...WITH AIRMASS LOOKING TOO DRY ACROSS THE SW MTS
WHERE DEW POINTS HAVE DROPPED INTO THE 20S...AND TOO CAPPED AND COOL
FOR THE SOUTHERN SANGRES. EACH SUCCESSIVE HRRR RUN HAS BACKED OFF
WITH QPF FOR THOSE AREAS...SO HAVE TRIMMED BACK POPS INTO THE SILENT
CATEGORY.
SOUTHWEST FLOW INCREASES OVER THE AREA FOR SUNDAY. NAM12 PICKS UP
SOME LOW LEVEL MOISTURE AND GENERATES SOME OROGRAPHIC SHOWERS ACROSS
THE SOUTHWEST MTS EARLY SATURDAY MORNING. THIS COULD BE A BIT
OVERDONE...BUT GFS HINTS AT THIS TOO SO WILL MAINTAIN SOME ISOLATED
SHOWERS FOR THAT AREA. BY AFTERNOON...MODELS SHOW SOME ISOLATED
THUNDERSTORMS SPREADING NORTH AND EASTWARD INTO THE SAWATCH AND
MOSQUITO RANGES AND THE SANGRES. OTHERWISE...TEMPERATURES SHOULD
REBOUND NICELY BACK INTO THE 80S FOR THE SE PLAINS WITH A MIX OF 60S
AND 70S FOR THE MOUNTAIN AREAS. SOUTHERLY WINDS WILL INCREASE
ACROSS THE AREA AS THE LEE TROF DEEPENS AHEAD OF THE NEXT
APPROACHING TROF. STRONGEST WINDS WILL BE ACROSS THE HIGHER PEAKS
IN THE AFTERNOON AND ALONG THE FAR EASTERN BORDER ON THE EAST SIDE
OF THE SFC TROF AXIS. BOTH AREAS COULD SEE GUSTS IN THE 25-30 KT
RANGE. -KT
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 331 PM MDT FRI SEP 20 2013
.SATURDAY NIGHT THROUGH SUNDAY NIGHT...TROUGH MOVES ACROSS THE
REGION SUNDAY AFTERNOON AND EVENING. MODELS HAVE SOME DIFFERENCES
ON THE STRENGTH OF THE TROUGH. THE NAM IS THE WEAKEST WHILE THE EC
IS THE STRONGEST. MAIN CONCERNS WITH TROUGH PASSAGE WOULD BE SNOW
LEVELS ALONG THE CONTINENTAL DIVIDE AND WINDS OVER THE EASTERN
MOUNTAINS AND PLAINS. MOST OF THE PRECIPITATION OVER THE
CONTINENTAL DIVIDE REGION OCCURS AHEAD OF THE COLDEST AIR
ALOFT...AND SNOW IS MOSTLY LIMITED TO THE HIGHEST PEAKS. SNOW
LEVELS COULD FALL BELOW TREE LINE BEFORE PRECIPITATION ENDS FOR
SOME ACCUMULATIONS. IF THE TROUGH IS DEEPER...MORE SNOW COULD FALL
BELOW TREE LINE. THE BEST CHANCES FOR SNOW BELOW TREELINE WILL BE
SUNDAY EVENING. SECOND CONCERN WILL BE WINDS. GUSTY SOUTH TO
SOUTHWEST WINDS WILL DEVELOP AHEAD OF THE TROUGH SUNDAY ON THE
PLAINS. GFS AND EC HAVE THE 500MB TROUGH CUT OFF BRIEFLY AS IT
LIFTS NORTHEAST INTO NEBRASKA. HAVE SOME CONCERNS FOR A BRIEF
PERIOD OF STRONG WINDS SUNDAY EVENING OVER THE EASTERN MOUNTAINS
AND INTERSTATE 25 CORRIDOR. MODELS DO NOT HAVE STRONG WINDS AT
THIS TIME...BUT HAVE SEEN WINDY CONDITIONS WITH SIMILAR PATTERNS.
.MONDAY THROUGH WEDNESDAY...DRY AND WARM PATTERN DEVELOPS BEHIND
DEPARTING TROUGH AND AHEAD OF THE NEXT TROUGH. BREEZY TO WINDY
CONDITIONS ARE POSSIBLE ON WEDNESDAY AS SOUTHWEST FLOW ALOFT
STRENGTHENS AHEAD OF THE NEXT TROUGH MOVING INTO THE PACIFIC
NORTHWEST.
.THRUSDAY AND FRIDAY...EC AND GFS HAVE THE TROUGH OVER THE
NORTHWEST US MOVING NORTHEASTWARD ACROSS THE NORTHERN ROCKIES.
REGION WILL BE ON THE SOUTHERN END OF THE TROUGH. BOTH MODELS
SUGGEST A COLD FRONT IN THE REGION...WITH THE POTENTIAL FOR SOME
UPSLOPE ON THE EASTERN PLAINS. TOO EARLY TO GET VERY SPECIFIC ON
DETAILS SUCH AS THE LOCATION OF THE FRONT...STRENGTH OF EASTERLY
UPSLOPE FLOW AND STRENGTH OF THE TROUGH. GRIDS HAVE A MODEST
COOLING TREND WITH SOME ISOLATED POPS. --PGW--
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1112 PM MDT FRI SEP 20 2013
VFR CONDITIONS AT KPUB AND KCOS THROUGH THE NEXT 24 HOURS
DIURNALLY DRIVEN WINDS. MODELS HAVE BACKED OFF ON THE PROBABILITY
OF FOG LATE TONIGHT AT KALS...BUT GIVEN THERE IS STILL SOME
MOISTURE ACROSS THE SAN LUIS VALLEY...FEEL THERE MAY STILL BE SOME
PATCHY FOG 12-15Z/SAT WITH REDUCED VIS AND CIGS. OTHERWISE EXPECT
VFR CONDITIONS AT KALS. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOZLEY
SHORT TERM...KT
LONG TERM...PGW
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
309 AM CDT SAT SEP 21 2013
.SYNOPSIS...
ISSUED AT 302 AM CDT SAT SEP 21 2013
FRIDAYS COLD FRONT STRETCHED FROM THE JAMES BAY SOUTHWARD TO KDTW TO
KDAY TO KMKL WITH SURFACE HIGH PRESSURE STRETCHING FROM SOUTHERN MANITOBA
SOUTHWARD TO THE TEXAS PANHANDLE. COOL...DRY AIR CONTINUED TO DROP
SOUTHWARD INTO THE UPPER MIDWEST FROM SOUTHERN CANADA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CDT SAT SEP 21 2013
THE 500 HPA TROUGH AXIS HAS SHIFTED EASTWARD INTO CENTRAL ILLINOIS
AND WISCONSIN THIS MORNING WITH NORTHWEST FLOW ALOFT ACROSS THE
REGION. STRATUS WAS UPSTREAM OF THE REGION ACROSS EASTERN NORTH
DAKOTA AND WESTERN MINNESOTA. THIS AREA OF CLOUDS IS REPRESENTED
WELL BY 850 HPA RH. THE 00 UTC GFS AND ECMWF BOTH DEPICT THIS AREA
OF CLOUDS DISSIPATING OR GRAZING THE CORNER OF NORTHWEST ILLINOIS
LATER THIS MORNING WHILE THE RAP DEPICTS THE MOISTURE
OVERSPREADING THE REGION. THE RAP HAS TOO MUCH MOISTURE IN THE LOW
LEVELS AND WILL THUS KEEP CLOUD COVER DOWN ACROSS THE REGION THIS
MORNING. OTHERWISE HIGH PRESSURE WILL SLOW BUILD SOUTHWARD ACROSS
THE REGION DURING THE DAY ON SATURDAY. SKIES WILL BE MOSTLY SUNNY
WITH A FEW CU DEVELOPING. A PLEASANT DAY WITH HIGH TEMPERATURES
FROM THE MID 60S ALONG HIGHWAY 20 TO AROUND 70 ACROSS SOUTHEAST
IOWA AND NORTHWEST MISSOURI WHICH IS 10 DEGREES BELOW NORMAL FOR
MID SEPTEMBER.
HIGH PRESSURE WILL BE SITTING OVER THE REGION SATURDAY NIGHT INTO
SUNDAY MORNING WITH CLEAR SKIES AND STRONG RADIATIONAL COOLING. KEPT
LOW TEMPERATURES FOR SUNDAY MORNING THE SAME AS PREVIOUS SHIFTS. A
CHILLY MORNING ON SUNDAY WITH TEMPERATURES REMAINING BELOW NORMAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 302 AM CDT SAT SEP 21 2013
A CONSISTENTLY PLEASANT FALL WEATHER FORECAST IS IN STORE FOR SUNDAY
THROUGH THURSDAY...AS DRY WEATHER DOMINATES THE MIDWEST WEATHER.
THIS WILL INITIALLY BE THROUGH A COOL GREAT LAKES HIGH
PRESSURE...ONE THAT IS BUILDING IN TODAY. THE RESULTING WEATHER
ASSOCIATED WITH THIS HIGH WILL BE SEVERAL DAYS OF LIGHT EASTERLY
FLOW AT LOW LEVELS...AND VERY LARGE DIURNAL DAILY TRENDS. GUIDANCE
CONTINUES TO BE COOLING IN THE PAST FEW DAYS FOR SUNDAY THROUGH
TUESDAY...AND WE WILL CONTINUE TO FORECAST NEAR THE COOLER SIDE OF
OVERNIGHT LOWS...AND NEAR THE MEAN OF GUIDANCE HIGHS. THIS RESULTS
IN LOWS MAINLY IN THE LOWER 40S EAST TO UPPER 40S WEST SUNDAY
NIGHT...AND UPPER 40S/LOW 50S MONDAY NIGHT. SUNDAY THROUGH
TUESDAY...HIGHS WILL GRADUALLY INCREASE FROM THE LOWER 70S...TO MID
70S. IN ALL...VERY PLEASANT WEATHER.
A MOISTURE STARVED UPPER LOW WILL WEAKEN OF MOVE NORTHEAST IN THE
UPPER MIDWEST TUESDAY. OTHER THAN A BRIEF INCREASE IN MID AND HIGH
CLOUDS TUESDAY...AND AN INCREASE IN SOUTH WINDS...THIS SYSTEM WILL
OFFER NO CHANCE OF MEASURABLE RAIN. IT IS HERE WHEN THE TWO MAIN
EXTEND MODELS DIVERGE. BOTH THE GFS AND ECMWF DEVELOP A LARGE
SYNOPTIC CUT OFF LOW IN THE ROCKIES BY WEDNESDAY. THE DEEP MOISTURE
RETURN ON BOTH MODELS INCREASES BY LATE THURSDAY...BUT THE ECMWF
BRINGS THIS ENERGY OUT OF THE SOUTHWEST IN ONE LARGE LOW...WELL TO
THE NORTH...VS THE GFS BRINGING ENERGY OUT IN TWO WAVES. THUS...IT
IS FASTER INITIALLY...AS IT BRINGS THE FRONT TO EASTERN IOWA BY
THURSDAY NIGHT...BUT AS ANOTHER WAVE LIFTS OUT OF THE ROCKIES
FRIDAY...MOISTURE CONVERGES ALONG THE BOUNDARY NEARBY TO PRODUCE A
SIGNIFICANT RAIN EVENT. THE ECMWF AND ITS SINGLE QUICK COLD FROPA
OFFERS VERY LITTLE THREAT OF RAIN. SO...WE ARE LEFT WITH A BLENDED
MODEL OUTPUT OF CHANCE POPS ON DAY 7. BOTH THE GFS AND ECMWF HAVE
BEEN CONSISTENT IN THESE SCENARIOS...AND BOTH APPEAR POSSIBLE.
THUS...TIME WILL TELL AS TO WHICH ENERGY DISTRIBUTION WILL BE
CORRECT.
ERVIN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1136 PM CDT FRI SEP 20 2013
HIGH PRESSURE OVER THE PLAINS WILL MOVE EAST INTO THE MISSISSIPPI
VALLEY BY SATURDAY AFTERNOON. VFR CONDITIONS WILL REMAIN OVER THE
AREA WITH SCATTERED CLOUDS BASED AROUND 4KFT REMAINING OVER THE
AREA THE REST OF TONIGHT AND SATURDAY.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DC
SHORT TERM...DC
LONG TERM...ERVIN
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1100 PM CDT Fri Sep 20 2013
.UPDATE...
ISSUED AT 1056 PM CDT FRI SEP 20 2013
UPDATED AVIATION SECTION FOR 06Z TAF ISSUANCE.
UPDATE A tight sfc wave (shown especially in NAM12 data) was moving newd
through the srn Pennyrile region of wrn ky this evening, offering a
potential source of lift. To the nw of this feature, light sfc winds
had already turned to the north ahead of a cold front moving through
the nwrn half of the PAH forecast area. Working against the feature
is the stabilizing atmosphere. What is left of any lower trop
instability will quickly exit the ern fringes of the region shortly.
Thus, there is no mention of tstms or locally heavy rain in the
forecast beyond 03z. The forward progress of the front seemed to be
on track at this time, and all pcpn should be out of the region by
12z.
&&
.SHORT TERM /Tonight through Sunday night/...
ISSUED AT 240 PM CDT FRI SEP 20 2013
Forecast seems to be panning out fairly well. Widespread rain has
overspread most of the forecast area this afternoon. Aside from a
convective cluster over western Kentucky...deep convection has been
largely absent. Instability has been limited by lack of solar
heating due to thickening mid/high clouds.
The qpf forecast seems to be on track...with the lowest amounts in
southern IL and southeast MO. Heavy rainfall is still occurring and
expected in western KY and possibly southwest IN. Due to dry
ground...any issues should be limited to urban and poor drainage
areas. Rainfall rates will continue to be locally over one inch per
hour in convection.
The latest HRRR is fairly close to the model consensus. The back
edge of the rain will move across the kpah/kevv areas in the 03z to
06z time frame. The precip will end in the khop area by 12z.
Clearing will occur on Saturday morning...with nothing more than
some scattered cu in the afternoon. 850 mb temps are forecast to
fall to around 10...which supports mos guidance highs in the mid
70s.
Little change in 850 mb temps or moisture profiles is forecast
through Sunday night. This will keep clear and cool conditions in
place...with daytime highs in the 70s and overnight lows in the mid
40s to near 50. North to northeast low level winds will slowly
decrease as high pressure builds overhead.
.LONG TERM /Monday through Friday/...
ISSUED AT 240 PM CDT FRI SEP 20 2013
As we head into next week, it now appears as though the upper level
high over the eastern U.S. will shift farther east as short wave
energy moves east into the MS River Valley. It still appears as
though our region may stay in between the two main branches of
energy, one passing to our north and the other just to our
south/east. If current trends continue, later forecasts may need to
mention a chc of rain in srn portions of west KY on Tuesday/Tue
night.
Thereafter...the upper high over the southeast U.S. will begin to
flex its muscle, and build north into the Ohio Valley. Thus... we
should see less cloud cover and warming temps as we head into the
Wed/Thu/Fri time frame. Most locations will likely be back into the
middle 80s by Wednesday afternoon. Humidity levels should stay
fairly comfortable until late in the week, when southerly flow will
develop ahead of an approaching cold front.
&&
.AVIATION...
ISSUED AT 1056 PM CDT FRI SEP 20 2013
CIGS VARYING FROM IFR TO VFR WILL CONTINUE FOR A FEW MORE HOURS.
PCPN WILL BE SLOW TO DEPART AS WELL. BUT EVENTUALLY LATE TONIGHT
BOTH WILL CEDE TO CLEARING SKIES AS POST FRONTAL DRIER/COOLER AIR
WORKS IN. SOME LIGHT NLYS SHOULD PICK UP AND PRECLUDE FOG...BUT
THIS SHOULD BE MONITORED CLOSELY AS MOS SUGGESTS OTHERWISE. TMRW
SHOULD BE NIL WX DAY WITH VFR THRU REMAINDER OF FORECAST.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
509 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A SOUTHERLY FLOW WILL BRING WARMER AND INCREASINGLY MOIST AIR TO
THE REGION TODAY. A STRONG COLD FRONT WILL APPROACH THE STATE TONIGHT
AND IS EXPECTED TO MOVE THROUGH THE FORECAST AREA ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CHALLENGE THIS TERM WILL BE CLOUDS AND DRIZZLE TODAY AND TIMING OF
RAIN AND INCREASING WINDS TONIGHT.
LATEST IR SATL 11.3-3.9 MICRON IMAGERY SHOWING LOW CLOUDS OVER THE
EASTERN 1/2 OF THE CWA THANKS IN PART TO THE SE FLOW. LOW CLOUDS
EXTEND FROM KFVE ALL THE DOWN TO THE KBHB REGION. FURTHER W, HIGH
CLOUDS MOVING ACROSS THE REGION. SOME DRIZZLE OCCURRING MAINLY
ACROSS THE E AND NE SECTIONS PER THE METARS AND WEBCAMS. THE NAM12
AND HRRR HANDLING THE CLOUDS WELL PER THE 06Z ANALYSIS. LATEST
RADAR TRENDS SHOWED DRIZZLE BECOMING MORE SPOTTY AS THE WINDS
BEGIN TO SHIFT TO A MORE S DIRECTION AND THIS PICKED UP WELL BY
THE 00Z NAM AS WELL. ACROSS THE DOWNEAST AND COAST, AREAS OF DRIZZLE
AND FOG THIS MORNING. CONDITIONS ARE EXPECTED TO IMPROVE LATER
THIS MORNING AS THE FLOW BECOMES MORE SLY AND LLVLS DRY OUT.
SUNSHINE RETURNING LATER ON WILL ALLOW FOR TEMPERATURES TO WARM
INTO THE 70S AWAY FROM THE DOWNEAST AND COAST AS S WIND WILL KEEP
TEMPERATURES DOWN ACROSS THE DOWNEAST AND COAST. THE LATEST NAM/RUC
SOUNDINGS POINT TO THIS TAKING PLACE. S WINDS PICKING UP TODAY AT
15 TO 20 MPH WITH HIGHER GUSTS AS SHOWN BY THE 00Z NAM AND 04Z HRRR.
THE TREND CONTINUES TO BE THAT RAIN WILL BE HELD OFF UNTIL LATER
TONIGHT AS A STRONG COLD FRONT BEGINS TO APCH FROM THE W. THE 00Z
RUNS OF THE NAM AND GFS SHOW AN INITIAL BATCH OF SHOWERS/RAIN OUT
AHEAD OF THE FRONT ACROSS THE W AND SW AREAS AND IN RESPONSE TO
AN UPPER LEVEL DISTURBANCE MOVING ACROSS THIS REGION. BUFKIT
PROFILES ALSO SHOW THE POTENTIAL FOR DRIZZLE TO SET UP AGAIN LATER
TONIGHT W/THE INCREASINGLY MOIST S FLOW. SOUNDINGS SHOW LLVLS
BELOW 900MBS MOISTENING W/DRY AIR ABOVE THIS LEVEL INDICATIVE OF
THE POTENTIAL FOR DRIZZLE. ADDED PERIODS OF DRIZZLE STARTING LATER
THIS EVENING AND THEN TRANSITIONING TO RAIN MOVES IN BY SUNDAY
MORNING. THE STEADIEST RAINFALL WILL BE W OF A CARIBOU-BANGOR
LINE. S WINDS WILL BE ON THE INCREASE AS WELL AS SHOWN BY THE
LATEST NAM AND GFS. KEPT WINDS 10 TO 20 MPH TONIGHT W/GUSTS TO 25
MPH.
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A COLD FRONT WILL CROSS THE REGION DURING SUNDAY. THE FRONT WILL
BE ACCOMPANIED BY A PERIOD OF STEADIER RAIN LATER SUNDAY MORNING
AND SUNDAY AFTERNOON. RAINFALL AMOUNTS DURING SUNDAY ARE EXPECTED
TO RANGE FROM THREE-QUARTERS TO ONE INCH AS A LOW LEVEL JET IN THE
925-850 MB LEVEL TRAVERSES THE REGION IN ADVANCE OF THE FRONT. THE
LOW LEVEL JET WILL ALSO RESULT IN GUSTY SOUTH WINDS IN ADVANCE OF
THE FRONT. HAVE INCLUDED THE MENTION OF ISOLATED THUNDER WITH SOME
ELEVATED INSTABILITY AHEAD OF THE FRONT AND THERE CURRENTLY IS
SOME LIGHTNING SHOWING UP IN ADVANCE OF THE BOUNDARY ATTM. THE
FRONT WILL MOVE EAST OF THE DOWNEAST COAST LATER SUNDAY AFTERNOON
ENDING THE STEADIEST RAINFALL.
EXPECT PARTLY TO MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS SUNDAY
NIGHT AND MONDAY AS AN UPPER LEVEL LOW CROSSES THE REGION WITH
PARTLY CLOUDY SKIES DOWNEAST. MUCH COOLER AIR WILL FLOW IN BEHIND
THE FRONT SUNDAY NIGHT AND MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM
THE LOW TO MID 40S AND HIGHS ON MONDAY WILL RANGE FROM THE LOW TO
MID 50S NORTH AND MID TO UPPER 50S DOWNEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AN UPPER LOW WILL SLOWLY MOVE EAST OF THE MARITIMES THROUGH MID
WEEK. THIS WILL KEEP A MAINLY DRY AND CHILLY WEATHER PATTERN
ACROSS THE REGION THROUGH MID WEEK.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR ATTM ACROSS ALL THE TERMINALS W/FOG A NUISANCE AS
VSBYS ARE <1 MILE AT KBGR AND KBHB. CONDITIONS ARE EXPECTED TO
IMPROVE LATER THIS MORNING TO MVFR AND THEN VFR. EXPECTING
CONDITIONS TO DROP BACK TO MVFR LATER IN THE EVENING AND THEN DOWN
TO IFR BY EARLY SUNDAY MORNING.
SHORT TERM:IFR/MVFR CONDITIONS CAN BE EXPECTED ON SUNDAY IN RAIN IN
ADVANCE OF AN APPROACHING COLD FRONT. GENERALLY VFR IS EXPECTED
SUNDAY NIGHT AND BEYOND EXCEPT SOME MVFR CIGS ARE IS POSSIBLE AT
TIMES MAINLY ACROSS NORTHERN AREAS.
&&
.MARINE...
NEAR TERM: FOG WILL LEAD TO NAVIGATIONAL PROBLEMS TODAY AS A SSE
WIND CONTINUES. DECIDED TO HOIST AN SCA FOR LATER TONIGHT INTO
SUNDAY AS WINDS ARE FCST TO INCREASE TO SUSTAINED SPEEDS OF 15 TO
20 KTS AND GUSTS TO 25 KTS. LATEST WNAWAVE COMING IN LINE ATTM PER
THE LATEST OBS SHOWING WAVE HEIGHTS OF 2 FT. DECIDED TO FOLLOW THE
DAYCREW`S LEAD OF INCREASING SEAS TO 4 TO 6 FT BY SUNDAY MORNING.
SHORT TERM: A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AS
WINDS/SEAS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EDT SUNDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS BUFFALO NY
422 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL CROSS OUR REGION TODAY AND BRING A
WIDESPREAD SOAKING RAINFALL. BEHIND THE FRONT...DRY WEATHER WILL
RETURN WITH TEMPERATURES FALLING BACK BELOW AVERAGE SUNDAY AND
MONDAY. AFTER THAT...DRY WEATHER SHOULD CONTINUE THROUGH MOST OF
NEXT WEEK...WITH TEMPERATURES WARMING BACK TO ABOVE AVERAGE
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DEEP LOW LEVEL THETA-E PLUME REMAINS FIRMLY IN PLACE JUST
UPSTREAM...LODGED WITHIN THE STEADY SOUTHWEST LOW LEVEL FLOW
ANCHORED IN ADVANCE OF THE COLD FRONT CURRENTLY WORKING THROUGH
EASTERN MICHIGAN/NORTHWEST OHIO. MOST RECENT HRRR AND SPC SSEO
OUTPUT SUGGESTING A GRADUAL EASTWARD SHIFT TO THE SOLID BAND OF
SHOWERS FOCUSED AHEAD OF THE COLD FRONT INTO THE REGION BEFORE
SUNRISE IN THE FAR WEST AND THE REMAINDER OF THE AREA THROUGH THE
DAY TODAY. THIS SUGGESTION LOOKS REASONABLE AS STRONGER LOW-MID
LEVEL ASCENT ATTRIBUTED TO FRONTAL CONVERGENCE...FAVORABLE EXIT
REGION JET DYNAMICS...AND THE ARRIVAL OF THE BETTER HEIGHTS
ATTENDANT WITH THE PV ANOMALY EJECTING ACROSS GREAT LAKES WILL WORK
ACROSS WESTERN AND NORTH CENTRAL NEW YORK THROUGH AT LEAST THE FIRST
HALF OF THE DAY. IMPRESSIVE MOISTURE QUALITY WORKING INTO THE REGION
WILL LEAD TO THE POTENTIAL FOR A STEADY MODERATE TO HEAVY RAINFALL
EVENT WITH MOST MODEL CONSENSUS SUGGESTING AMOUNTS EXCEEDING AN INCH.
THESE AMOUNTS MAY BE ENOUGH TO BRING SOME LOCALIZED FLOOD
PROBLEMS...BUT LIKELY NOT ENOUGH TO CAUSE SIGNIFICANT ISSUES WITH
LOCAL RIVERS AND CREEKS. THE POTENTIAL FOR THUNDER APPEARS LESS
FAVORABLE WITH VERY POOR INSTABILITY PARAMETERS THEREFORE WILL
DOWNPLAY THE POTENTIAL WITH ONLY THE SUGGESTION OF ISOLATED COVERAGE.
POST FRONTAL COLD/DRY ADVECTION RAMPS UP IN WAKE OF FRONT TONIGHT...
WITH MODELS AGREEING ON 850 MB TEMPERATURES FALLING TO 2-4C IN
DEEPENING NORTHWEST FLOW REGIME. COULD SEE A PERIOD OF CLEARING...BUT
EXPECT A BKN/OVC STRATOCUMULUS CLOUD DECK TO SETTLE IN FOR MUCH OF
THE NIGHT GIVEN CYCLONIC FLOW AND MOISTURE FLUX OFF THE LAKES PER
LAKE-850 MB TEMPERATURE DIFFERENTIALS. CANNOT RULE A FEW
INSTABILITY/LAKE EFFECT SHOWERS AS COLD POCKET ALOFT PIVOTS
THROUGH THE LOWER LAKES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE COLD FRONT WILL BE WELL EAST OF THE REGION ON SUNDAY
MORNING...BUT MOISTURE LINGERING BEHIND THE FRONT WILL ENCOUNTER AN
UPSLOPE NORTHWESTERLY WIND AND WILL LIKELY FORM AN INLAND CLOUD DECK
DURING A LARGE PART OF SUNDAY. THE COLDER CORE OF THE UPPER
TROUGH/LOW WILL BE FAR ENOUGH TO THE NORTH TO LIMIT THE MID LEVEL
INSTABILITY DURING SUNDAY AFTERNOON...BUT COLDER BOUNDARY LAYER
TEMPS WILL PUT QUITE A CHILL IN THE AIR FOR THE DAYTIME WITH HIGH
TEMPS ONLY IN THE MID TO UPPER 50S.
CONTINUED INFLUX OF DRIER AIR ALOFT WILL RESULT IN A CLEARING TREND
FOR SUNDAY NIGHT WITH COLD ADVECTION AND PRIME RADIATIONAL COOLING
DROPPING OVERNIGHT TEMPS TO THE UPPER 30S TO LOWER 40S. EXPECT
VALLEY FOG ACROSS THE SOUTHERN TIER AND PATCHY FROST ACROSS THE
HILLTOPS OF THE SOUTHERN TIER AND WESTERN ADIRONDACKS.
COOL HIGH PRESSURE CENTERED OVER ONTARIO AND WESTERN QUEBEC WILL
MAINTAIN A COOL INFLUX OF DRY AIR DURING THE BEGINNING OF THE
WORKWEEK. SUNSHINE WILL ABOUND ON MONDAY BUT COOL AIR WILL HOLD HIGH
TEMPS TO THE MID TO UPPER 50S ONCE AGAIN. OVERNIGHT LOWS WILL BE A
SHADE LESS CHILLY ON MONDAY NIGHT AS THE AIRMASS MODIFIES SLOWLY
OVER TIME. LOW TEMPS WILL BE IN THE UPPER 30S TO LOWER 40S ONCE
AGAIN...AND STILL THAT CHANCE FOR FROST PATCHES ON THE EXPOSED
HILLTOPS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AN EXTENDED PERIOD OF QUIET WEATHER WILL BE IN PLACE FOR MUCH OF
NEXT WEEK COURTESY OF HIGH PRESSURE EXTENDED FROM THE OHIO VALLEY
INTO NEW ENGLAND. TUESDAY AND WEDNESDAY TEMPERATURES WILL CLIMB BACK
TO NORMAL LATE SEPTEMBER LEVELS. MODELS SHOW A RETURN OF WARM AIR
FOR THURSDAY AND FRIDAY AS THE SURFACE HIGH CENTERED ALONG THE EAST
COAST. HIGHS WILL RUN IN THE 70S AGAIN THURSDAY AND FRIDAY WITH OUR
NEXT CHANCE FOR RAIN LIKELY HOLDING OFF UNTIL NEXT WEEKEND.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL CROSS THE REGION SATURDAY. A LINE OF SHOWERS
LOCATED BETWEEN LAKE HURON AND LAKE ONTARIO WILL CONTINUE TO MOVE TO
THE EAST AND IMPACT WESTERN TAF SITES AFTER 07Z. THE SHOWER
ACTIVITY WILL BECOME MORE WIDESPREAD AS THE FRONT PUSHES SLOWLY TO
THE EAST. SOME OF THIS RAIN MAY BE LOCALLY HEAVY AT TIMES...AND
WILL CAUSE VFR CONDITIONS TO LOWER TO MVFR/IFR FROM WEST TO EAST
LATE TONIGHT AND SATURDAY MORNING. EMBEDDED THUNDER IS LOOKING
LESS LIKELY WITH ALL MENTION OF THUNDER REMOVED FROM THE TAFS.
OVERNIGHT INTO EARLY SATURDAY MORNING...A BRIEF PERIOD OF LOW LEVEL
WIND SHEAR WILL ALSO BE POSSIBLE AT ALL SITES AS A 40+ KT LOW LEVEL
JET SLIDES EAST ACROSS THE AREA IN ADVANCE OF THE APPROACHING FRONT.
OUTLOOK...
SATURDAY NIGHT...LINGERING IFR/MVFR.
SUNDAY...BECOMING VFR.
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
&&
.MARINE...
A COLD FRONT WILL PUSH ACROSS THE CENTRAL AND EASTERN GREAT LAKES
TODAY WITH WAVES INCREASING ON THE EASTERN ENDS OF BOTH LAKES ERIE
AND ONTARIO. ADVISORY LEVEL WINDS AND WAVES WILL CONTINUE
ACROSS THE EAST END OF LAKE ONTARIO AS THE FRONT APPROACHES.
EXPECT THE WINDS TO SHIFT TO NORTHWESTERLY FOLLOWING THE FRONTAL
PASSAGE TONIGHT. ADVISORY CRITERIA MAY DEVELOP ALONG THE SOUTH SHORE
OF LAKE ONTARIO LATE TONIGHT AND SUNDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LOZ045.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...JJR/TJP/TMA
MARINE...TMA
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
528 AM PDT SAT SEP 21 2013
.SYNOPSIS...
A STORM SYSTEM MOVING THROUGH THE AREA TODAY WILL BRING COOL TEMPERATURES
AND RELATIVELY WET WEATHER. THUNDERSTORMS ARE POSSIBLE ACROSS THE
SACRAMENTO VALLEY IN THE AFTERNOON AND EVENING. DRY WEATHER SUNDAY
INTO MONDAY THEN MOUNTAIN SHOWERS POSSIBLE TUESDAY INTO WEDNESDAY.
BREEZY CONDITIONS LATE TUESDAY THROUGH EARLY FRIDAY. BELOW NORMAL
TEMPERATURES THROUGH MID WEEK WITH DRYER AND WARMER CONDITIONS
TOWARDS THE END OF THE WEEK.
.DISCUSSION...
A WEAKENING COLD FRONT PASSING THROUGH THE AREA IS PRODUCING SOME
SCATTERED RAIN SHOWERS NORTH OF INTERSTATE 80. THE HRRR MODEL
SHOWS A MUCH MORE DEFINED SW TO NE BAND OF HEAVIER RAIN MOVING
INLAND REACHING REDDING BY MID MORNING AND THE DELTA AROUND NOON.
RADAR SHOWS A PORTION OF THIS BAND CURRENTLY ALONG THE NORTHWEST
CALIFORNIA COAST ASSOCIATED WITH THE MAIN TROUGH. THIS BAND WILL
GRADUALLY SHIFT EASTWARD WITH THE REST OF THE SACRAMENTO VALLEY
AND NORTHERN SAN JOAQUIN SEEING THIS HEAVIER PRECIPITATION BY
AROUND NOON. PEAK PRECIPITATION IN THE SIERRA SHOULD BE REACHED
LATE IN THE AFTERNOON. SNOW LEVELS AROUND 7500 FEET IN THE SIERRA COULD
BRING A DUSTING OF SNOW TO HIGHER MOUNTAINS. MOUNTAINS TO THE
NORTH COULD SEE LIGHT SNOW DOWN TO 7000 FEET OR SO.
CAPE AND LI LEVELS SUGGEST AN AREA OF FAIRLY STRONG INSTABILITY
CENTERED BETWEEN CHICO AND YUBA CITY BY MID DAY. EXPECT HEAVIER
SHOWERS AND THUNDERSTORMS TO DEVELOP IN THAT AREA THROUGH THE
AFTERNOON AND INTO THE EARLY EVENING. SOME THUNDERSTORMS MAY ALSO
DEVELOP ELSEWHERE IN THE SACRAMENTO VALLEY. BREAKS IN THE CLOUDS
IN THE AFTERNOON MAY ALLOW FOR ADDITIONAL DESTABILIZATION BUT THIS
IS STILL UNCERTAIN. THE GFS SOUNDING AROUND CHICO HAS CAPE REACHING OVER
700 J/KG BY LATE AFTERNOON AND MODIFYING THE SOUNDING SUGGESTS
LEVELS OVER 800 J/KG. THE NAM IS NOT AS IMPRESSIVE AND HAS CAPE
LEVELS AROUND 450 J/KG. GENERAL SHEAR LEVELS AT 0-1 KM AND 0-6 KM
DO NOT LOOK TOO IMPRESSIVE (PEAKING AROUND 9 AND 36 M/S BY 2 PM)
BUT COULD BE SEE SOME DECENT SHEAR DEVELOP LOCALLY IN THE BUTTE
COUNTY AREA WITH A CONVERGENCE AREA. WILL HAVE TO WATCH THIS SETUP
CLOSELY TO SEE IF THE POTENTIAL FOR SOME SEVERE STORMS DEVELOPS.
PRECIPITATION WILL CONTINUE INTO THE EVENING THEN SHOULD SHIFT
EASTWARD AFTER MIDNIGHT WITH JUST SOME LINGERING MOUNTAIN SHOWERS,
MAINLY OVER THE SIERRA. THE TROUGH PULLS EAST OF THE AREA QUICKLY
ON SUNDAY, WITH SOME MORNING FOG POSSIBLE IN MOUNTAIN VALLEYS. SKIES
SHOULD CLEAR BY MIDDAY. TEMPERATURES WILL REBOUND A BIT, BUT LOOK
TO REMAIN A BIT BELOW NORMAL A BRINGING A CRISP FIRST DAY OF FALL.
HIGHS MONDAY AND TUESDAY WILL BE MORE MILD AND SEASONABLE. THE
FLOW ALOFT REMAINS ACTIVE ACROSS THE EASTERN PACIFIC GOING INTO
NEXT WEEK. PRECIPITATION ON MONDAY SHOULD MAINLY BE TO THE NORTH
OF THE SHASTA COUNTY MOUNTAINS, WITH SOME LIGHT SHOWERS OVER THAT
AREA POSSIBLE MONDAY NIGHT INTO TUESDAY AS AN INSIDE SLIDER SYSTEM
DROPS DOWN IN NE CALIFORNIA/N NEVADA. EK
.EXTENDED DISCUSSION (WEDNESDAY THROUGH SATURDAY)
BY WEDNESDAY THE TROUGH WILL BE CENTERED OVER THE GREAT BASIN WITH
CHANCES OF SOME PRECIPITATION OVER THE SIERRA. WITH THE AREA
BEING ON THE BACK PORTION OF THE TROUGH WEDNESDAY AND THURSDAY,
NORTHERLY WINDS WILL PICK UP AND BECOME BREEZY THROUGH THE VALLEY.
THIS COULD BRING A RETURN OF INCREASED FIRE DANGER TO THE AREA
INTO FRIDAY WITH LOWERING HUMIDITY LEVELS. CONDITIONS WILL BE DRY
AND COOL WITH BELOW AVERAGE TEMPERATURES. EK
.EXTENDED DISCUSSION (WEDNESDAY THROUGH SATURDAY)
BY WEDNESDAY THE TROUGH WILL BE CENTERED OVER THE GREAT BASIN WITH
CHANCES OF SOME PRECIPITATION OVER THE SIERRA. WITH THE AREA
BEING ON THE BACK PORTION OF THE TROUGH WEDNESDAY AND THURSDAY,
NORTHERLY WINDS WILL PICK UP AND BECOME BREEZY THROUGH THE VALLEY.
THIS COULD BRING A RETURN OF INCREASED FIRE DANGER TO THE AREA
INTO FRIDAY WITH LOWERING HUMIDITY LEVELS. CONDITIONS WILL BE DRY
AND COOL WITH BELOW AVERAGE TEMPERATURES. EK
&&
.AVIATION...
FRONTAL SYSTEM WILL MOVE THROUGH NORCAL THIS AFTERNOON. ISOLATED
TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON OVER
MUCH OF NOCAL. GENERALLY VFR/MVFR WITH LOCAL IFR CONDITIONS ARE
EXPECTED IN THE VALLEY IN -SHRA AND IFR/LIFR CONDITIONS OVER THE
MOUNTAINS. SNOW LEVELS WILL LOWER TO AROUND 7500 FT BY AFTERNOON.
SOUTH TO SOUTHWEST WINDS 10-20 KT WITH LOCAL GUSTS TO 40 KTS OVER
THE MOUNTAINS.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1051 AM CDT SAT SEP 21 2013
.UPDATE...
ISSUED AT 1050 AM CDT SAT SEP 21 2013
PLEASANT FALL-LIKE DAY IN PROGRESS WITH CURRENT TEMPERATURES IN
THE MID 50S TO LOWER 60S. THESE READINGS APPEAR ON TARGET FOR
AFTERNOON HIGHS IN THE MID 60S TO LOWER 70S.
I AM WATCHING AN AREA OF STRATUS ACROSS MUCH OF WI AND EASTERN MN
WHERE THE LOW LEVELS ARE QUITE MOIST. THESE CLOUDS ARE SPREADING
SOUTHWARD BUT ALSO WILL BE RUNNING INTO DRIER AIR. OUR NW IL
COUNTIES LOOK VULNERABLE TO HAVING AT LEAST PARTLY SUNNY SKIES AND
HAVE INCREASED THE SKY GRIDS FOR THAT AREA. ELSEWHERE SCATTERED
CUMULUS/STRATOCUMULUS EXPECTED.
&&
.SYNOPSIS...
ISSUED AT 302 AM CDT SAT SEP 21 2013
FRIDAYS COLD FRONT STRETCHED FROM THE JAMES BAY SOUTHWARD TO KDTW TO
KDAY TO KMKL WITH SURFACE HIGH PRESSURE STRETCHING FROM SOUTHERN MANITOBA
SOUTHWARD TO THE TEXAS PANHANDLE. COOL...DRY AIR CONTINUED TO DROP
SOUTHWARD INTO THE UPPER MIDWEST FROM SOUTHERN CANADA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CDT SAT SEP 21 2013
THE 500 HPA TROUGH AXIS HAS SHIFTED EASTWARD INTO CENTRAL ILLINOIS
AND WISCONSIN THIS MORNING WITH NORTHWEST FLOW ALOFT ACROSS THE
REGION. STRATUS WAS UPSTREAM OF THE REGION ACROSS EASTERN NORTH
DAKOTA AND WESTERN MINNESOTA. THIS AREA OF CLOUDS IS REPRESENTED
WELL BY 850 HPA RH. THE 00 UTC GFS AND ECMWF BOTH DEPICT THIS AREA
OF CLOUDS DISSIPATING OR GRAZING THE CORNER OF NORTHWEST ILLINOIS
LATER THIS MORNING WHILE THE RAP DEPICTS THE MOISTURE
OVERSPREADING THE REGION. THE RAP HAS TOO MUCH MOISTURE IN THE LOW
LEVELS AND WILL THUS KEEP CLOUD COVER DOWN ACROSS THE REGION THIS
MORNING. OTHERWISE HIGH PRESSURE WILL SLOW BUILD SOUTHWARD ACROSS
THE REGION DURING THE DAY ON SATURDAY. SKIES WILL BE MOSTLY SUNNY
WITH A FEW CU DEVELOPING. A PLEASANT DAY WITH HIGH TEMPERATURES
FROM THE MID 60S ALONG HIGHWAY 20 TO AROUND 70 ACROSS SOUTHEAST
IOWA AND NORTHWEST MISSOURI WHICH IS 10 DEGREES BELOW NORMAL FOR
MID SEPTEMBER.
HIGH PRESSURE WILL BE SITTING OVER THE REGION SATURDAY NIGHT INTO
SUNDAY MORNING WITH CLEAR SKIES AND STRONG RADIATIONAL COOLING. KEPT
LOW TEMPERATURES FOR SUNDAY MORNING THE SAME AS PREVIOUS SHIFTS. A
CHILLY MORNING ON SUNDAY WITH TEMPERATURES REMAINING BELOW NORMAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 302 AM CDT SAT SEP 21 2013
A CONSISTENTLY PLEASANT FALL WEATHER FORECAST IS IN STORE FOR SUNDAY
THROUGH THURSDAY...AS DRY WEATHER DOMINATES THE MIDWEST WEATHER.
THIS WILL INITIALLY BE THROUGH A COOL GREAT LAKES HIGH
PRESSURE...ONE THAT IS BUILDING IN TODAY. THE RESULTING WEATHER
ASSOCIATED WITH THIS HIGH WILL BE SEVERAL DAYS OF LIGHT EASTERLY
FLOW AT LOW LEVELS...AND VERY LARGE DIURNAL DAILY TRENDS. GUIDANCE
CONTINUES TO BE COOLING IN THE PAST FEW DAYS FOR SUNDAY THROUGH
TUESDAY...AND WE WILL CONTINUE TO FORECAST NEAR THE COOLER SIDE OF
OVERNIGHT LOWS...AND NEAR THE MEAN OF GUIDANCE HIGHS. THIS RESULTS
IN LOWS MAINLY IN THE LOWER 40S EAST TO UPPER 40S WEST SUNDAY
NIGHT...AND UPPER 40S/LOW 50S MONDAY NIGHT. SUNDAY THROUGH
TUESDAY...HIGHS WILL GRADUALLY INCREASE FROM THE LOWER 70S...TO MID
70S. IN ALL...VERY PLEASANT WEATHER.
A MOISTURE STARVED UPPER LOW WILL WEAKEN OF MOVE NORTHEAST IN THE
UPPER MIDWEST TUESDAY. OTHER THAN A BRIEF INCREASE IN MID AND HIGH
CLOUDS TUESDAY...AND AN INCREASE IN SOUTH WINDS...THIS SYSTEM WILL
OFFER NO CHANCE OF MEASURABLE RAIN. IT IS HERE WHEN THE TWO MAIN
EXTEND MODELS DIVERGE. BOTH THE GFS AND ECMWF DEVELOP A LARGE
SYNOPTIC CUT OFF LOW IN THE ROCKIES BY WEDNESDAY. THE DEEP MOISTURE
RETURN ON BOTH MODELS INCREASES BY LATE THURSDAY...BUT THE ECMWF
BRINGS THIS ENERGY OUT OF THE SOUTHWEST IN ONE LARGE LOW...WELL TO
THE NORTH...VS THE GFS BRINGING ENERGY OUT IN TWO WAVES. THUS...IT
IS FASTER INITIALLY...AS IT BRINGS THE FRONT TO EASTERN IOWA BY
THURSDAY NIGHT...BUT AS ANOTHER WAVE LIFTS OUT OF THE ROCKIES
FRIDAY...MOISTURE CONVERGES ALONG THE BOUNDARY NEARBY TO PRODUCE A
SIGNIFICANT RAIN EVENT. THE ECMWF AND ITS SINGLE QUICK COLD FROPA
OFFERS VERY LITTLE THREAT OF RAIN. SO...WE ARE LEFT WITH A BLENDED
MODEL OUTPUT OF CHANCE POPS ON DAY 7. BOTH THE GFS AND ECMWF HAVE
BEEN CONSISTENT IN THESE SCENARIOS...AND BOTH APPEAR POSSIBLE.
THUS...TIME WILL TELL AS TO WHICH ENERGY DISTRIBUTION WILL BE
CORRECT.
ERVIN
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 624 AM CDT SAT SEP 21 2013
HIGH PRESSURE WILL MOVE EASTWARD THROUGH THE DAY ON SATURDAY
BRINGING VFR CONDITIONS TO ALL TAF SITES THROUGH THE PERIOD.
HOWEVER...AN AREA OF MVFR STRATUS CURRENTLY SITS ACROSS NORTHERN
MINNNESOTA AND WISCONSIN BUT CONFIDENCE IS LOW THAT IT WILL EFFECT
AREA TAF SITES. EXPECT A FEW TO SCT CU TO DEVELOP LATE THIS
MORING AND CONTINUE INTO THE EARLY AFTERNOON WITH THE BASES AOA
4KFT. NORTH TO NORTHWEST WINDS WILL INCREASE TO 10 TO 15 KNOTS BY
EARLY AFTERNOON AND DIMINISH BY EARLY EVENING. WINDS WILL DROP TO
5 KNOTS OR LESS AND SWING AROUND TO AN EASTERLY DIRECTION AFTER
00 UTC ON SUNDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...DC
SHORT TERM...DC
LONG TERM...ERVIN
AVIATION...DC
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
635 AM CDT SAT SEP 21 2013
.SYNOPSIS...
ISSUED AT 302 AM CDT SAT SEP 21 2013
FRIDAYS COLD FRONT STRETCHED FROM THE JAMES BAY SOUTHWARD TO KDTW TO
KDAY TO KMKL WITH SURFACE HIGH PRESSURE STRETCHING FROM SOUTHERN MANITOBA
SOUTHWARD TO THE TEXAS PANHANDLE. COOL...DRY AIR CONTINUED TO DROP
SOUTHWARD INTO THE UPPER MIDWEST FROM SOUTHERN CANADA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CDT SAT SEP 21 2013
THE 500 HPA TROUGH AXIS HAS SHIFTED EASTWARD INTO CENTRAL ILLINOIS
AND WISCONSIN THIS MORNING WITH NORTHWEST FLOW ALOFT ACROSS THE
REGION. STRATUS WAS UPSTREAM OF THE REGION ACROSS EASTERN NORTH
DAKOTA AND WESTERN MINNESOTA. THIS AREA OF CLOUDS IS REPRESENTED
WELL BY 850 HPA RH. THE 00 UTC GFS AND ECMWF BOTH DEPICT THIS AREA
OF CLOUDS DISSIPATING OR GRAZING THE CORNER OF NORTHWEST ILLINOIS
LATER THIS MORNING WHILE THE RAP DEPICTS THE MOISTURE
OVERSPREADING THE REGION. THE RAP HAS TOO MUCH MOISTURE IN THE LOW
LEVELS AND WILL THUS KEEP CLOUD COVER DOWN ACROSS THE REGION THIS
MORNING. OTHERWISE HIGH PRESSURE WILL SLOW BUILD SOUTHWARD ACROSS
THE REGION DURING THE DAY ON SATURDAY. SKIES WILL BE MOSTLY SUNNY
WITH A FEW CU DEVELOPING. A PLEASANT DAY WITH HIGH TEMPERATURES
FROM THE MID 60S ALONG HIGHWAY 20 TO AROUND 70 ACROSS SOUTHEAST
IOWA AND NORTHWEST MISSOURI WHICH IS 10 DEGREES BELOW NORMAL FOR
MID SEPTEMBER.
HIGH PRESSURE WILL BE SITTING OVER THE REGION SATURDAY NIGHT INTO
SUNDAY MORNING WITH CLEAR SKIES AND STRONG RADIATIONAL COOLING. KEPT
LOW TEMPERATURES FOR SUNDAY MORNING THE SAME AS PREVIOUS SHIFTS. A
CHILLY MORNING ON SUNDAY WITH TEMPERATURES REMAINING BELOW NORMAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 302 AM CDT SAT SEP 21 2013
A CONSISTENTLY PLEASANT FALL WEATHER FORECAST IS IN STORE FOR SUNDAY
THROUGH THURSDAY...AS DRY WEATHER DOMINATES THE MIDWEST WEATHER.
THIS WILL INITIALLY BE THROUGH A COOL GREAT LAKES HIGH
PRESSURE...ONE THAT IS BUILDING IN TODAY. THE RESULTING WEATHER
ASSOCIATED WITH THIS HIGH WILL BE SEVERAL DAYS OF LIGHT EASTERLY
FLOW AT LOW LEVELS...AND VERY LARGE DIURNAL DAILY TRENDS. GUIDANCE
CONTINUES TO BE COOLING IN THE PAST FEW DAYS FOR SUNDAY THROUGH
TUESDAY...AND WE WILL CONTINUE TO FORECAST NEAR THE COOLER SIDE OF
OVERNIGHT LOWS...AND NEAR THE MEAN OF GUIDANCE HIGHS. THIS RESULTS
IN LOWS MAINLY IN THE LOWER 40S EAST TO UPPER 40S WEST SUNDAY
NIGHT...AND UPPER 40S/LOW 50S MONDAY NIGHT. SUNDAY THROUGH
TUESDAY...HIGHS WILL GRADUALLY INCREASE FROM THE LOWER 70S...TO MID
70S. IN ALL...VERY PLEASANT WEATHER.
A MOISTURE STARVED UPPER LOW WILL WEAKEN OF MOVE NORTHEAST IN THE
UPPER MIDWEST TUESDAY. OTHER THAN A BRIEF INCREASE IN MID AND HIGH
CLOUDS TUESDAY...AND AN INCREASE IN SOUTH WINDS...THIS SYSTEM WILL
OFFER NO CHANCE OF MEASURABLE RAIN. IT IS HERE WHEN THE TWO MAIN
EXTEND MODELS DIVERGE. BOTH THE GFS AND ECMWF DEVELOP A LARGE
SYNOPTIC CUT OFF LOW IN THE ROCKIES BY WEDNESDAY. THE DEEP MOISTURE
RETURN ON BOTH MODELS INCREASES BY LATE THURSDAY...BUT THE ECMWF
BRINGS THIS ENERGY OUT OF THE SOUTHWEST IN ONE LARGE LOW...WELL TO
THE NORTH...VS THE GFS BRINGING ENERGY OUT IN TWO WAVES. THUS...IT
IS FASTER INITIALLY...AS IT BRINGS THE FRONT TO EASTERN IOWA BY
THURSDAY NIGHT...BUT AS ANOTHER WAVE LIFTS OUT OF THE ROCKIES
FRIDAY...MOISTURE CONVERGES ALONG THE BOUNDARY NEARBY TO PRODUCE A
SIGNIFICANT RAIN EVENT. THE ECMWF AND ITS SINGLE QUICK COLD FROPA
OFFERS VERY LITTLE THREAT OF RAIN. SO...WE ARE LEFT WITH A BLENDED
MODEL OUTPUT OF CHANCE POPS ON DAY 7. BOTH THE GFS AND ECMWF HAVE
BEEN CONSISTENT IN THESE SCENARIOS...AND BOTH APPEAR POSSIBLE.
THUS...TIME WILL TELL AS TO WHICH ENERGY DISTRIBUTION WILL BE
CORRECT.
ERVIN
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 624 AM CDT SAT SEP 21 2013
HIGH PRESSURE WILL MOVE EASTWARD THROUGH THE DAY ON SATURDAY
BRINGING VFR CONDITIONS TO ALL TAF SITES THROUGH THE PERIOD.
HOWEVER...AN AREA OF MVFR STRATUS CURRENTLY SITS ACROSS NORTHERN
MINNNESOTA AND WISCONSIN BUT CONFIDENCE IS LOW THAT IT WILL EFFECT
AREA TAF SITES. EXPECT A FEW TO SCT CU TO DEVELOP LATE THIS
MORING AND CONTINUE INTO THE EARLY AFTERNOON WITH THE BASES AOA
4KFT. NORTH TO NORTHWEST WINDS WILL INCREASE TO 10 TO 15 KNOTS BY
EARLY AFTERNOON AND DIMINISH BY EARLY EVENING. WINDS WILL DROP TO
5 KNOTS OR LESS AND SWING AROUND TO AN EASTERLY DIRECTION AFTER
00 UTC ON SUNDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DC
SHORT TERM...DC
LONG TERM...ERVIN
AVIATION...DC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
935 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A SOUTHERLY FLOW WILL BRING WARMER AND INCREASINGLY MOIST AIR TO
THE REGION TODAY. A STRONG COLD FRONT WILL APPROACH THE STATE TONIGHT
AND IS EXPECTED TO MOVE THROUGH THE FORECAST AREA ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE: MADE SOME FAIRLY MINOR CHANGES TO SKY COVER,
TEMPERATURE, DEW POINT, AND WIND GRIDS FOR THIS MORNING INTO THE
EARLY AFTERNOON BASED ON CURRENT CURRENT CONDITIONS. ALSO REMOVED
PATCHY DRIZZLE FROM THE FORECAST FOR THIS MORNING AS THIS NO
LONGER LOOKS TO BE AN ISSUE. NO OTHER CHANGES AT THIS TIME.
PREVIOUS DISCUSSION... CHALLENGE THIS TERM WILL BE
CLOUDS AND DRIZZLE TODAY AND TIMING OF RAIN AND INCREASING WINDS
TONIGHT.
LATEST IR SATL 11.3-3.9 MICRON IMAGERY SHOWING LOW CLOUDS OVER THE
EASTERN 1/2 OF THE CWA THANKS IN PART TO THE SE FLOW. LOW CLOUDS
EXTEND FROM KFVE ALL THE DOWN TO THE KBHB REGION. FURTHER W, HIGH
CLOUDS MOVING ACROSS THE REGION. SOME DRIZZLE OCCURRING MAINLY
ACROSS THE E AND NE SECTIONS PER THE METARS AND WEBCAMS. THE NAM12
AND HRRR HANDLING THE CLOUDS WELL PER THE 06Z ANALYSIS. LATEST
RADAR TRENDS SHOWED DRIZZLE BECOMING MORE SPOTTY AS THE WINDS
BEGIN TO SHIFT TO A MORE S DIRECTION AND THIS PICKED UP WELL BY
THE 00Z NAM AS WELL. ACROSS THE DOWNEAST AND COAST, AREAS OF DRIZZLE
AND FOG THIS MORNING. CONDITIONS ARE EXPECTED TO IMPROVE LATER
THIS MORNING AS THE FLOW BECOMES MORE SLY AND LLVLS DRY OUT.
SUNSHINE RETURNING LATER ON WILL ALLOW FOR TEMPERATURES TO WARM
INTO THE 70S AWAY FROM THE DOWNEAST AND COAST AS S WIND WILL KEEP
TEMPERATURES DOWN ACROSS THE DOWNEAST AND COAST. THE LATEST NAM/RUC
SOUNDINGS POINT TO THIS TAKING PLACE. S WINDS PICKING UP TODAY AT
15 TO 20 MPH WITH HIGHER GUSTS AS SHOWN BY THE 00Z NAM AND 04Z HRRR.
THE TREND CONTINUES TO BE THAT RAIN WILL BE HELD OFF UNTIL LATER
TONIGHT AS A STRONG COLD FRONT BEGINS TO APCH FROM THE W. THE 00Z
RUNS OF THE NAM AND GFS SHOW AN INITIAL BATCH OF SHOWERS/RAIN OUT
AHEAD OF THE FRONT ACROSS THE W AND SW AREAS AND IN RESPONSE TO
AN UPPER LEVEL DISTURBANCE MOVING ACROSS THIS REGION. BUFKIT
PROFILES ALSO SHOW THE POTENTIAL FOR DRIZZLE TO SET UP AGAIN LATER
TONIGHT W/THE INCREASINGLY MOIST S FLOW. SOUNDINGS SHOW LLVLS
BELOW 900MBS MOISTENING W/DRY AIR ABOVE THIS LEVEL INDICATIVE OF
THE POTENTIAL FOR DRIZZLE. ADDED PERIODS OF DRIZZLE STARTING LATER
THIS EVENING AND THEN TRANSITIONING TO RAIN MOVES IN BY SUNDAY
MORNING. THE STEADIEST RAINFALL WILL BE W OF A CARIBOU-BANGOR
LINE. S WINDS WILL BE ON THE INCREASE AS WELL AS SHOWN BY THE
LATEST NAM AND GFS. KEPT WINDS 10 TO 20 MPH TONIGHT W/GUSTS TO 25
MPH.
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A COLD FRONT WILL CROSS THE REGION DURING SUNDAY. THE FRONT WILL
BE ACCOMPANIED BY A PERIOD OF STEADIER RAIN LATER SUNDAY MORNING
AND SUNDAY AFTERNOON. RAINFALL AMOUNTS DURING SUNDAY ARE EXPECTED
TO RANGE FROM THREE-QUARTERS TO ONE INCH AS A LOW LEVEL JET IN THE
925-850 MB LEVEL TRAVERSES THE REGION IN ADVANCE OF THE FRONT. THE
LOW LEVEL JET WILL ALSO RESULT IN GUSTY SOUTH WINDS IN ADVANCE OF
THE FRONT. HAVE INCLUDED THE MENTION OF ISOLATED THUNDER WITH SOME
ELEVATED INSTABILITY AHEAD OF THE FRONT AND THERE CURRENTLY IS
SOME LIGHTNING SHOWING UP IN ADVANCE OF THE BOUNDARY ATTM. THE
FRONT WILL MOVE EAST OF THE DOWNEAST COAST LATER SUNDAY AFTERNOON
ENDING THE STEADIEST RAINFALL.
EXPECT PARTLY TO MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS SUNDAY
NIGHT AND MONDAY AS AN UPPER LEVEL LOW CROSSES THE REGION WITH
PARTLY CLOUDY SKIES DOWNEAST. MUCH COOLER AIR WILL FLOW IN BEHIND
THE FRONT SUNDAY NIGHT AND MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM
THE LOW TO MID 40S AND HIGHS ON MONDAY WILL RANGE FROM THE LOW TO
MID 50S NORTH AND MID TO UPPER 50S DOWNEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AN UPPER LOW WILL SLOWLY MOVE EAST OF THE MARITIMES THROUGH MID
WEEK. THIS WILL KEEP A MAINLY DRY AND CHILLY WEATHER PATTERN
ACROSS THE REGION THROUGH MID WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR ATTM ACROSS ALL THE TERMINALS W/FOG A NUISANCE AS
VSBYS ARE <1 MILE AT KBGR AND KBHB. CONDITIONS ARE EXPECTED TO
IMPROVE LATER THIS MORNING TO MVFR AND THEN VFR. EXPECTING
CONDITIONS TO DROP BACK TO MVFR LATER IN THE EVENING AND THEN DOWN
TO IFR BY EARLY SUNDAY MORNING.
SHORT TERM:IFR/MVFR CONDITIONS CAN BE EXPECTED ON SUNDAY IN RAIN IN
ADVANCE OF AN APPROACHING COLD FRONT. GENERALLY VFR IS EXPECTED
SUNDAY NIGHT AND BEYOND EXCEPT SOME MVFR CIGS ARE IS POSSIBLE AT
TIMES MAINLY ACROSS NORTHERN AREAS.
&&
.MARINE...
NEAR TERM: FOG WILL LEAD TO NAVIGATIONAL PROBLEMS TODAY AS A SSE
WIND CONTINUES. DECIDED TO HOIST AN SCA FOR LATER TONIGHT INTO
SUNDAY AS WINDS ARE FCST TO INCREASE TO SUSTAINED SPEEDS OF 15 TO
20 KTS AND GUSTS TO 25 KTS. LATEST WNAWAVE COMING IN LINE ATTM PER
THE LATEST OBS SHOWING WAVE HEIGHTS OF 2 FT. DECIDED TO FOLLOW THE
DAY CREW`S LEAD OF INCREASING SEAS TO 4 TO 6 FT BY SUNDAY MORNING.
SHORT TERM: A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AS
WINDS/SEAS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EDT SUNDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...FITZSIMMONS/HEWITT/DUDA
MARINE...FITZSIMMONS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
649 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A SOUTHERLY FLOW WILL BRING WARMER AND INCREASINGLY MOIST AIR TO
THE REGION TODAY. A STRONG COLD FRONT WILL APPROACH THE STATE TONIGHT
AND IS EXPECTED TO MOVE THROUGH THE FORECAST AREA ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
650 AM UPDATE: ADJUSTED THE SKY COVER TO CARRY LOW CLOUDS A BIT
LONGER AS EVIDENT FROM THE LATEST SATL IMAGERY SHOWING LOW CLOUDS
HANGING TOUGH AND EXPANDING A BIT BACK TO THE W COVER THE
PISCATAQUIS COUNTY REGION. EXTENDED FOG AND DRIZZLE FOR THE
DOWNEAST AND COAST THROUGH LATE MORNING.
PREVIOUS DISCUSSION...
CHALLENGE THIS TERM WILL BE CLOUDS AND DRIZZLE TODAY AND TIMING
OF RAIN AND INCREASING WINDS TONIGHT.
LATEST IR SATL 11.3-3.9 MICRON IMAGERY SHOWING LOW CLOUDS OVER THE
EASTERN 1/2 OF THE CWA THANKS IN PART TO THE SE FLOW. LOW CLOUDS
EXTEND FROM KFVE ALL THE DOWN TO THE KBHB REGION. FURTHER W, HIGH
CLOUDS MOVING ACROSS THE REGION. SOME DRIZZLE OCCURRING MAINLY
ACROSS THE E AND NE SECTIONS PER THE METARS AND WEBCAMS. THE NAM12
AND HRRR HANDLING THE CLOUDS WELL PER THE 06Z ANALYSIS. LATEST
RADAR TRENDS SHOWED DRIZZLE BECOMING MORE SPOTTY AS THE WINDS
BEGIN TO SHIFT TO A MORE S DIRECTION AND THIS PICKED UP WELL BY
THE 00Z NAM AS WELL. ACROSS THE DOWNEAST AND COAST, AREAS OF DRIZZLE
AND FOG THIS MORNING. CONDITIONS ARE EXPECTED TO IMPROVE LATER
THIS MORNING AS THE FLOW BECOMES MORE SLY AND LLVLS DRY OUT.
SUNSHINE RETURNING LATER ON WILL ALLOW FOR TEMPERATURES TO WARM
INTO THE 70S AWAY FROM THE DOWNEAST AND COAST AS S WIND WILL KEEP
TEMPERATURES DOWN ACROSS THE DOWNEAST AND COAST. THE LATEST NAM/RUC
SOUNDINGS POINT TO THIS TAKING PLACE. S WINDS PICKING UP TODAY AT
15 TO 20 MPH WITH HIGHER GUSTS AS SHOWN BY THE 00Z NAM AND 04Z HRRR.
THE TREND CONTINUES TO BE THAT RAIN WILL BE HELD OFF UNTIL LATER
TONIGHT AS A STRONG COLD FRONT BEGINS TO APCH FROM THE W. THE 00Z
RUNS OF THE NAM AND GFS SHOW AN INITIAL BATCH OF SHOWERS/RAIN OUT
AHEAD OF THE FRONT ACROSS THE W AND SW AREAS AND IN RESPONSE TO
AN UPPER LEVEL DISTURBANCE MOVING ACROSS THIS REGION. BUFKIT
PROFILES ALSO SHOW THE POTENTIAL FOR DRIZZLE TO SET UP AGAIN LATER
TONIGHT W/THE INCREASINGLY MOIST S FLOW. SOUNDINGS SHOW LLVLS
BELOW 900MBS MOISTENING W/DRY AIR ABOVE THIS LEVEL INDICATIVE OF
THE POTENTIAL FOR DRIZZLE. ADDED PERIODS OF DRIZZLE STARTING LATER
THIS EVENING AND THEN TRANSITIONING TO RAIN MOVES IN BY SUNDAY
MORNING. THE STEADIEST RAINFALL WILL BE W OF A CARIBOU-BANGOR
LINE. S WINDS WILL BE ON THE INCREASE AS WELL AS SHOWN BY THE
LATEST NAM AND GFS. KEPT WINDS 10 TO 20 MPH TONIGHT W/GUSTS TO 25
MPH.
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A COLD FRONT WILL CROSS THE REGION DURING SUNDAY. THE FRONT WILL
BE ACCOMPANIED BY A PERIOD OF STEADIER RAIN LATER SUNDAY MORNING
AND SUNDAY AFTERNOON. RAINFALL AMOUNTS DURING SUNDAY ARE EXPECTED
TO RANGE FROM THREE-QUARTERS TO ONE INCH AS A LOW LEVEL JET IN THE
925-850 MB LEVEL TRAVERSES THE REGION IN ADVANCE OF THE FRONT. THE
LOW LEVEL JET WILL ALSO RESULT IN GUSTY SOUTH WINDS IN ADVANCE OF
THE FRONT. HAVE INCLUDED THE MENTION OF ISOLATED THUNDER WITH SOME
ELEVATED INSTABILITY AHEAD OF THE FRONT AND THERE CURRENTLY IS
SOME LIGHTNING SHOWING UP IN ADVANCE OF THE BOUNDARY ATTM. THE
FRONT WILL MOVE EAST OF THE DOWNEAST COAST LATER SUNDAY AFTERNOON
ENDING THE STEADIEST RAINFALL.
EXPECT PARTLY TO MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS SUNDAY
NIGHT AND MONDAY AS AN UPPER LEVEL LOW CROSSES THE REGION WITH
PARTLY CLOUDY SKIES DOWNEAST. MUCH COOLER AIR WILL FLOW IN BEHIND
THE FRONT SUNDAY NIGHT AND MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM
THE LOW TO MID 40S AND HIGHS ON MONDAY WILL RANGE FROM THE LOW TO
MID 50S NORTH AND MID TO UPPER 50S DOWNEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AN UPPER LOW WILL SLOWLY MOVE EAST OF THE MARITIMES THROUGH MID
WEEK. THIS WILL KEEP A MAINLY DRY AND CHILLY WEATHER PATTERN
ACROSS THE REGION THROUGH MID WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR ATTM ACROSS ALL THE TERMINALS W/FOG A NUISANCE AS
VSBYS ARE <1 MILE AT KBGR AND KBHB. CONDITIONS ARE EXPECTED TO
IMPROVE LATER THIS MORNING TO MVFR AND THEN VFR. EXPECTING
CONDITIONS TO DROP BACK TO MVFR LATER IN THE EVENING AND THEN DOWN
TO IFR BY EARLY SUNDAY MORNING.
SHORT TERM:IFR/MVFR CONDITIONS CAN BE EXPECTED ON SUNDAY IN RAIN IN
ADVANCE OF AN APPROACHING COLD FRONT. GENERALLY VFR IS EXPECTED
SUNDAY NIGHT AND BEYOND EXCEPT SOME MVFR CIGS ARE IS POSSIBLE AT
TIMES MAINLY ACROSS NORTHERN AREAS.
&&
.MARINE...
NEAR TERM: FOG WILL LEAD TO NAVIGATIONAL PROBLEMS TODAY AS A SSE
WIND CONTINUES. DECIDED TO HOIST AN SCA FOR LATER TONIGHT INTO
SUNDAY AS WINDS ARE FCST TO INCREASE TO SUSTAINED SPEEDS OF 15 TO
20 KTS AND GUSTS TO 25 KTS. LATEST WNAWAVE COMING IN LINE ATTM PER
THE LATEST OBS SHOWING WAVE HEIGHTS OF 2 FT. DECIDED TO FOLLOW THE
DAYCREW`S LEAD OF INCREASING SEAS TO 4 TO 6 FT BY SUNDAY MORNING.
SHORT TERM: A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AS
WINDS/SEAS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EDT SUNDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1100 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A COLD FRONT ACROSS THE GREAT LAKES AND OHIO VALLEY WILL PROGRESS
EAST TODAY...BEFORE MOVING THROUGH THE AREA TONIGHT. HIGH
PRESSURE BUILDS INTO THE REGION SUNDAY AND DOMINATES THE WEATHER
PATTERN FOR MUCH OF THE WEEK AHEAD.
&&
.NEAR TERM /THROUGH TONIGHT/...
14Z SFC ANALYSIS SHOWS A COLD FRONT IS LOCATED ALONG THE WRN
SPINE OF THE APPALACHIANS. 12Z RAOBS AND LATEST WATER VAPOR AND
BLENDED TOTAL PWAT SATELLITE IMAGERY SAT...IMAGERY SHOW AN
ATMOSPHERIC RIVER FROM THE TROPICAL PACIFIC AND GULF OF
MEXICO..EXITING POLEWARD UP INTO INTO ERN CANADA. THIS PLUME OF
MOISTURE AND WIDESPREAD SHOWERS...WHICH IS JUXTAPOSED WITH A SLY
LLVL JET...WILL PROGRESS INTO THE CWA FROM WEST TO EAST THIS AFTN.
SOME OF THESE SHOWERS THAT ARE COINCIDENT ALONG AND AHEAD OF FROPA
WILL BE MODERATE TO LOCALLY HEAVY WHEN PWATS INCREASE TO AROUND
1.75 INCHES. WIDESPREAD QPF AMOUNTS BETWEEN ONE-HALF TO ONE INCH
AND LOCALLY HIGHER AMNTS POSSIBLE. FLOODING THREAT WILL BE LOW
DUE TO DRY ANTECEDENT CONDITIONS. HAVE ADJUSTED POPS BASED ON
LATEST EXPECTED PROGRESSION OF THE FRONT.
OVC SKIES WILL LIMIT AMNT OF DAYTIME HEATING WITH MAX TEMPS ONLY
IN THE 70S THIS AFTN. THE ONE EXCEPTION WILL BE THE MD CHSPK BAY
AND WRN SHORE LOCATIONS...WHERE LEADING EDGE OF DENSE OVC HAS YET
TO REACH AND MAX TEMPS NEAR 80F CERTAINLY POSSIBLE. WEAK LOW- AND
MID-LVL LAPSE RATES WILL NOT SUPPORT MUCH INSTABILITY TDA. FCST
EQUIL LVLS HEIGHTS FROM THE LATEST RAP ARE LOW AND NOT SUPPORTIVE
OF TSTMS TDA. THE ONE EXCEPTION WHERE ISO TSTMS WERE KEPT IN THE
FCST IS THE WRN SHORE OF THE BAY.
RAIN/CONVECTIVE CHANCES WILL HOLD IN LONGER OVER EASTERN SECTIONS
INTO LATER TONIGHT...PARTICULARLY SOUTHERN MD NORTH TO BALTIMORE
AND HARFORD COUNTIES WITH ALL OTHER REMAINING ACTIVITY COMING TO
AN END BEFORE MIDNIGHT.
WILL HAVE TO WATCH FOR FOG DEVELOPMENT LATE TONIGHT INTO EARLY
SUNDAY DEPENDING ON EXTENT OF CLEARING AND MOIST GROUND FROM
RAINFALL. POST-FRONTAL NWLY SURGE OF DRIER AIR IN THEORY WOULD
LIMIT FOG POTENTIAL...BUT SOME SHELTERED VLYS MAY BE PROTECTED
ENOUGH FROM THE WINDS TO ALLOW FOR FOG..
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FRONTAL SYSTEM EARLY SUNDAY MORNING WILL BE OVER THE DELMARVA.
A CHANCE OF SHOWERS OVER THE LOWER BAY IS POSSIBLE EARLY
SUNDAY...BUT OVERALL SKIES ON SUNDAY WILL CLEAR AND EXPECT
ABUNDANT SUNSHINE THROUGHOUT THE CWA.
FOR MON THROUGH TUE...HIGH PRESSURE WILL DOMINATE THE WEATHER
ACROSS THE REGION...ALL GUIDANCE IS CONSISTENT IN THAT REGARD.
TEMPERATURES WILL BE BELOW SEASONAL NORMALS MON AND TUE. DRY
AIRMASS OVER THE REGION WILL ALLOW NIGHTTIME MINS TO BE
PARTICULARLY COOL BOTH MON AND TUE MORNINGS.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
FOR WED...THERE IS NOW DISAGREEMENT BETWEEN THE 00Z/GFS AND NEW 00Z/21
ECMWF. THE GFS MAINTAINS UPPER LEVEL RIDGING ALONG THE EASTERN US
WHILE THE ECMWF BRINGS A POTENT-LOOKING UPPER LOW ACROSS THE MID
ATLANTIC REGION ON WED-WED NIGHT. FOR NOW...WENT WITH A MORE
OPTIMISTIC SOLN FROM THE GFS...AND THIS IS ALSO WHAT WPC SEEMS TO
THINK AS WELL. A GRADUAL WARM UP IS EXPECTED THUR AND FRI...UNDER
HIGH PRESSURE.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS FOR MOST OF THE CWA THIS MRNG EXCEPT FOR
CHO...WHICH IS SOCKED IN WITH LOW CLOUDS AND FOG. EXPECT THIS TO
TEMPORARILY MIX OUT AROUND MIDDAY UNTIL CIGS/VSBYS LOWER THIS AFTN
WHEN WIDESPREAD SHRA ARRIVE. SHRA WILL BE MOD TO LOCALLY HVY
ACROSS ALL TERMINALS AS THE COLD FRONT MOVES THRU FROM W TO E
BETWEEN 20Z-03Z. MOSTLY MVFR CIGS/VSBYS EXPECTED...PERHAPS BRIEF
IFR IN THIS HEAVIER ACTIVITY. CLEARING EXPECTED DURING THE
EVENING FROM WEST TO EAST...HOWEVER...PATCHY TO AREAS OF FOG WILL
BE POSSIBLE OVERNIGHT INTO EARLY SUNDAY.
SUNDAY THROUGH WEDNESDAY...EXPECT VFR CONDITIONS AS SUBSIDENCE
ASSOCIATED WITH HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR TO
PARTLY CLOUDY. ONLY ISSUE COULD BE FOR CHO TAF ON WED...AS ECMWF
MODEL AT ODDS WITH GFS...ECMWF SUGGESTS SOME MVFR CLOUDS ASSOCIATED
WITH LOW PRESSURE OVER NORTH CAROLINA COULD SPREAD AS FAR NORTH TO
AFFECT CHO.
&&
.MARINE...
SLY FLOW AHEAD OF A COLD FRONT WILL STRENGTHEN THIS AFTN AND EVE.
SCA EXPANDED TO INCLUDE ALL MARINE ZONES...BUT SLY CHANNELING WILL
PRODUCE MORE FREQUENT SCA LVL GUSTS IN THE MAIN STEM OF THE CHSPK
BAY. SHOWERS AND ISOLATED THUNDERSTORMS MAY PRODUCE LOCALLY GUSTY
WINDS AS WELL DURING THE MID TO LATE AFTN AND EVE. COLD FRONT
WILL OCCUR IN THE WATERS LATE TONIGHT WITH WINDS SHIFTING TO
NORTHWEST.
NW WINDS BEHIND THE FRONT NOT AS STRONG AS THE PRE-
FRONTAL SLY WINDS...BUT DEEPER MIXING MAY PRODUCE GUSTS NEAR SCA
LVLS ON SUN. WINDS SHIFT TO NORTH DURING THE AFTN AS HIPRES BUILDS
IN. THE PRES GRADIENT DOES INCREASE SUN NIGHT INTO EARLY MON.
NORTHERLY CHANNELLING ON WINDS EARLY MON COULD RESULT IN SOME SCA
GUSTS THROUGH MID MORNING BEFORE GRADIENT SLACKENS.
&&
.TIDES/COASTAL FLOODING...
SLY WINDS AHEAD OF A COLD FRONT HAS ACCOMPANIED AN INCREASE IN
POSITIVE TIDAL DEPARTURES. ANOMALIES IN THE BAY ARE AROUND 2/3
FOOT AS OF 1030 AM...AND ARE FCST TO INCREASE TO AROUND A FT BY
HIGH TIDE THIS EVE. COMBINATION OF A RECENT FULL MOON AND THESE
EXPECTED ANOMALIES WAS ENOUGH TO ISSUE A COASTAL FLOOD ADVISORY
ALONG THE WRN SHORE FROM ANNE ARUNDEL TO HARFORD COUNTIES. WILL
ALSO NEED TO MONITOR THE POTENTIAL FOR MINOR FLOODING IN
WASHINGTON CHANNEL IF ANOMALIES INCREASE TO AROUND 3/4 FT
ABOVE /THERE IS ENOUGH UNCERTAINTY TO HOLD OFF ON AN ADIVOSRY AS
OF NOW./
WINDS WILL SHIFT FROM SOUTHERLY TO WESTERLY LATER TODAY/TONIGHT
WITH WATER LEVELS DECREASING OVERNIGHT INTO SUNDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT
SUNDAY FOR MDZ007.
COASTAL FLOOD ADVISORY FROM 6 PM TO 11 PM EDT THIS EVENING FOR
MDZ011-014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ530>534-
539>541-543.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ535>538-
542.
&&
$$
SYNOPSIS...JRK/
NEAR TERM...JRK/KRW
SHORT TERM...SMZ
LONG TERM...SMZ
AVIATION...JRK/SMZ
MARINE...JRK/SMZ
TIDES/COASTAL FLOODING...JRK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
746 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL CROSS OUR REGION TODAY AND BRING A
WIDESPREAD SOAKING RAINFALL. BEHIND THE FRONT...DRY WEATHER WILL
RETURN WITH TEMPERATURES FALLING BACK BELOW AVERAGE SUNDAY AND
MONDAY. AFTER THAT...DRY WEATHER SHOULD CONTINUE THROUGH MOST OF
NEXT WEEK...WITH TEMPERATURES WARMING BACK TO ABOVE AVERAGE
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DEEP LOW LEVEL THETA-E PLUME REMAINS FIRMLY IN PLACE JUST
UPSTREAM...LODGED WITHIN THE STEADY SOUTHWEST LOW LEVEL FLOW
ANCHORED IN ADVANCE OF THE COLD FRONT CURRENTLY WORKING THROUGH
EASTERN MICHIGAN/NORTHWEST OHIO. MOST RECENT HRRR AND SPC SSEO
OUTPUT SUGGESTING A GRADUAL EASTWARD SHIFT TO THE SOLID BAND OF
SHOWERS FOCUSED AHEAD OF THE COLD FRONT INTO THE REGION BEFORE
SUNRISE IN THE FAR WEST AND THE REMAINDER OF THE AREA THROUGH THE
DAY TODAY. THIS SUGGESTION LOOKS REASONABLE AS STRONGER LOW-MID
LEVEL ASCENT ATTRIBUTED TO FRONTAL CONVERGENCE...FAVORABLE EXIT
REGION JET DYNAMICS...AND THE ARRIVAL OF THE BETTER HEIGHTS
ATTENDANT WITH THE PV ANOMALY EJECTING ACROSS GREAT LAKES WILL WORK
ACROSS WESTERN AND NORTH CENTRAL NEW YORK THROUGH AT LEAST THE FIRST
HALF OF THE DAY. IMPRESSIVE MOISTURE QUALITY WORKING INTO THE REGION
WILL LEAD TO THE POTENTIAL FOR A STEADY MODERATE TO HEAVY RAINFALL
EVENT WITH MOST MODEL CONSENSUS SUGGESTING AMOUNTS EXCEEDING AN INCH.
THESE AMOUNTS MAY BE ENOUGH TO BRING SOME LOCALIZED FLOOD
PROBLEMS...BUT LIKELY NOT ENOUGH TO CAUSE SIGNIFICANT ISSUES WITH
LOCAL RIVERS AND CREEKS. THE POTENTIAL FOR THUNDER APPEARS LESS
FAVORABLE WITH VERY POOR INSTABILITY PARAMETERS THEREFORE WILL
DOWNPLAY THE POTENTIAL WITH ONLY THE SUGGESTION OF ISOLATED COVERAGE.
POST FRONTAL COLD/DRY ADVECTION RAMPS UP IN WAKE OF FRONT TONIGHT...
WITH MODELS AGREEING ON 850 MB TEMPERATURES FALLING TO 2-4C IN
DEEPENING NORTHWEST FLOW REGIME. COULD SEE A PERIOD OF CLEARING...BUT
EXPECT A BKN/OVC STRATOCUMULUS CLOUD DECK TO SETTLE IN FOR MUCH OF
THE NIGHT GIVEN CYCLONIC FLOW AND MOISTURE FLUX OFF THE LAKES PER
LAKE-850 MB TEMPERATURE DIFFERENTIALS. CANNOT RULE A FEW
INSTABILITY/LAKE EFFECT SHOWERS AS COLD POCKET ALOFT PIVOTS
THROUGH THE LOWER LAKES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE COLD FRONT WILL BE WELL EAST OF THE REGION ON SUNDAY
MORNING...BUT MOISTURE LINGERING BEHIND THE FRONT WILL ENCOUNTER AN
UPSLOPE NORTHWESTERLY WIND AND WILL LIKELY FORM AN INLAND CLOUD DECK
DURING A LARGE PART OF SUNDAY. THE COLDER CORE OF THE UPPER
TROUGH/LOW WILL BE FAR ENOUGH TO THE NORTH TO LIMIT THE MID LEVEL
INSTABILITY DURING SUNDAY AFTERNOON...BUT COLDER BOUNDARY LAYER
TEMPS WILL PUT QUITE A CHILL IN THE AIR FOR THE DAYTIME WITH HIGH
TEMPS ONLY IN THE MID TO UPPER 50S.
CONTINUED INFLUX OF DRIER AIR ALOFT WILL RESULT IN A CLEARING TREND
FOR SUNDAY NIGHT WITH COLD ADVECTION AND PRIME RADIATIONAL COOLING
DROPPING OVERNIGHT TEMPS TO THE UPPER 30S TO LOWER 40S. EXPECT
VALLEY FOG ACROSS THE SOUTHERN TIER AND PATCHY FROST ACROSS THE
HILLTOPS OF THE SOUTHERN TIER AND WESTERN ADIRONDACKS.
COOL HIGH PRESSURE CENTERED OVER ONTARIO AND WESTERN QUEBEC WILL
MAINTAIN A COOL INFLUX OF DRY AIR DURING THE BEGINNING OF THE
WORKWEEK. SUNSHINE WILL ABOUND ON MONDAY BUT COOL AIR WILL HOLD HIGH
TEMPS TO THE MID TO UPPER 50S ONCE AGAIN. OVERNIGHT LOWS WILL BE A
SHADE LESS CHILLY ON MONDAY NIGHT AS THE AIRMASS MODIFIES SLOWLY
OVER TIME. LOW TEMPS WILL BE IN THE UPPER 30S TO LOWER 40S ONCE
AGAIN...AND STILL THAT CHANCE FOR FROST PATCHES ON THE EXPOSED
HILLTOPS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AN EXTENDED PERIOD OF QUIET WEATHER WILL BE IN PLACE FOR MUCH OF
NEXT WEEK COURTESY OF HIGH PRESSURE EXTENDED FROM THE OHIO VALLEY
INTO NEW ENGLAND. TUESDAY AND WEDNESDAY TEMPERATURES WILL CLIMB BACK
TO NORMAL LATE SEPTEMBER LEVELS. MODELS SHOW A RETURN OF WARM AIR
FOR THURSDAY AND FRIDAY AS THE SURFACE HIGH CENTERED ALONG THE EAST
COAST. HIGHS WILL RUN IN THE 70S AGAIN THURSDAY AND FRIDAY WITH OUR
NEXT CHANCE FOR RAIN LIKELY HOLDING OFF UNTIL NEXT WEEKEND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A SLOW MOVING COLD FRONT WILL CROSS THE REGION TODAY. A BAND OF
SHOWERS WILL WORK EASTWARD ACROSS THE REGION THROUGH THISAFTERNOON.
WIDESPREAD IFR CONDITIONS ASSOCIATED WITH THIS BAND. EMBEDDED
THUNDER IS LOOKING LESS LIKELY WITH ALL MENTION OF THUNDER REMOVED
FROM THE TAFS.
THIS MORNING...A BRIEF PERIOD OF LOW LEVEL WIND SHEAR WILL ALSO BE
POSSIBLE AT KART AS A 40+ KT LOW LEVEL JET SLIDES EAST IN ADVANCE
OF THE APPROACHING FRONT.
IMPROVING CONDITIONS WILL OCCUR BEHIND THE FRONT WITH JIAG/KBUF/KROC
BECOMING VFR BY LATE AFTERNOON...BUT NOT UNTIL LATE EVENING AT
KART AND KJHW.
OUTLOOK...
SUNDAY THROUGH WEDNESDAY...VFR.
&&
.MARINE...
A COLD FRONT WILL PUSH ACROSS THE CENTRAL AND EASTERN GREAT LAKES
TODAY WITH WAVES INCREASING ON THE EASTERN ENDS OF BOTH LAKES ERIE
AND ONTARIO. ADVISORY LEVEL WINDS AND WAVES WILL CONTINUE
ACROSS THE EAST END OF LAKE ONTARIO AS THE FRONT APPROACHES.
EXPECT THE WINDS TO SHIFT TO NORTHWESTERLY FOLLOWING THE FRONTAL
PASSAGE TONIGHT. ADVISORY CRITERIA MAY DEVELOP ALONG THE SOUTH SHORE
OF LAKE ONTARIO LATE TONIGHT AND SUNDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LOZ045.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EDT SAT SEP 21 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY EASTWARD THROUGH THE AREA LATE TODAY
THROUGH SUNDAY MORNING. HIGH PRESSURE WILL BUILD BACK OVER THE
REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED A COLD FRONT FROM THE LOWER GREAT
LAKES THROUGH THE OHIO AND TENNESSEE VALLEYS...HEADED TOWARD THE
TN/NC BORDER. 12Z SOUNDINGS TOWARD KGSO AND KRNK...ALONG WITH THE
UPPER-AIR ANALYSIS...SHOWED A LAYER OF GOOD DRYING AROUND 500MB...
COINCIDENT WITH SOME CLEARING OVER THE SOUTHWEST PIEDMONT AND A LACK
OF RETURNS ON NEARBY RADARS TO THE WEST. AS THE SHORTWAVE RIDGE ALSO
OVER THE AREA OF DRYING/CLEARING DAMPENS AND MOVES EAST...DIFFLUENCE
INCREASES FOR THE AFTERNOON. ALREADY...WIDESPREAD SHOWERS WERE NOTED
ON REGIONAL RADARS MOVING INTO THE WESTERN QUARTER OF THE STATE...
MOVING GRADUALLY EAST.
LIFT INCREASES FOR THE AFTERNOON OVER CENTRAL NORTH CAROLINA AS
DIFFLUENCE AHEAD OF THE SURFACE COLD FRONT MOVES EAST. IN THE MOIST
AIR MASS OVER CENTRAL NORTH CAROLINA...WITH PRECIPITABLE WATER
VALUES FROM 1.75 INCHES TO 2 INCHES THIS AFTERNOON...AND AS THE LIFT
INCREASES SCATTERED SHOWERS SHOULD DEVELOP EARLY...FOLLOWED BY MORE
NUMEROUS TO WIDESPREAD SHOWERS SPREADING GRADUALLY FROM WEST TO EAST
OVER THE AREA. THE LATEST RAP SHOWS A MODERATELY-STRONG MID-LEVEL
SHORTWAVE WEAKENING SOME AS IT MOVES EAST AND APPROACHES CENTRAL
NORTH CAROLINA...AND THE RAP 850MB THETA-E DOES NOT RECOVER FROM IN
THAT MODEL/S FORECAST FROM HIGH VALUES EARLIER THIS MORNING. ALSO...
MLCAPE OVER THE AREA BARELY REGISTERS...WITH LOW DCAPE AND LIFTED
INDICES ONLY FALLING TO AROUND 0C. GIVEN THE CURRENT UPPER-AIR AND
AIRCRAFT SOUNDINGS...ALONG WITH THE RAP FORECAST SOUNDINGS THROUGH
00Z...ALL SHOWING SOME WARMING ALOFT AROUND 500MB WHICH DOES NOT
SEEM TO CHANGE GIVEN UPSTREAM TEMPERATURES...THUNDER SHOULD BE HARD
TO COME BY AT LEAST INTO THE EARLY EVENING. TEMPERATURE PROFILES ON
RAP MODEL SOUNDINGS THROUGH 00Z ARE ALL AVERAGING AT OR RIGHT OF THE
MOIST ADIABAT. PRECIPITATION INTENSITY COULD WANE OVER OUR AREA
COMPARED TO RADAR RETURNS UPSTREAM...BUT THERE SHOULD BE ENOUGH
COVERAGE FOR NUMEROUS TO WIDESPREAD SHOWERS...AND POSSIBLY AN
ISOLATED RUMBLE OF THUNDER...FROM THE LATE AFTERNOON INTO THE
EVENING HOURS. CURRENT TEMPERATURE FORECAST IS LIKELY AT OR JUST
BEYOND THE HIGH END OF THE EXPECTED RANGE AND WILL WATCH THE
PROGRESSION OF FLEETING CLEARING ON VISIBLE IMAGERY...LIKELY NEEDING
TO MODIFY LOWER MAXES IN AREAS IN A SUBSEQUENT LATE-MORNING UPDATE.
TONIGHT...WHILE NEARLY THE ENTIRE FORECAST AREA SHOULD SEE
MEASURABLE RAIN...THE SPECIFICS OF ENDING TIMING AND AMOUNTS ARE
LESS CERTAIN. WILL STICK CLOSER TO THE NAM/GFS/WRF-ARW/WRK-NMM/SREF
MEAN TIMING...SHOWING THE HIGH POPS TAPERING DOWN LATE TONIGHT FROM
NW TO SE...BUT WILL SLOW THE EXIT DOWN BY A COUPLE OF HOURS AS A NOD
TO THE CONSISTENT ECMWF. AND...WHILE WE COULD SEE A FEW TRAINING
SHOWERS CAUSING LOCALLY HIGHER RAIN TOTALS...WILL HOLD AMOUNTS DOWN
GIVEN THIS VERY REAL POSSIBILITY OF A "CAROLINA SPLIT" IN THE PRECIP
SHIELD...AS THE BETTER DYNAMIC FORCING FOR ASCENT (INCLUDING UPPER
DIVERGENCE WITH THE POLAR STREAM JET) COULD HEAD TO OUR NORTH...
WHILE THE BETTER THERMODYNAMICS AND LOW LEVEL MASS CONVERGENCE MAY
HOLD JUST TO OUR SOUTH. LOWS 60-66 ARE IN LINE WITH STATISTICAL
GUIDANCE.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 255 AM SATURDAY...
WITH THE ABOVE REASONING IN MIND... WILL HOLD ONTO A CHANCE OF RAIN
IN THE EAST THROUGH SUNDAY MORNING. FORECAST SOUNDINGS DEPICT LOTS
OF DRY AND RATHER STABLE MID-UPPER LEVEL AIR PUSHING IN FROM THE WNW
BEHIND THE MID LEVEL TROUGH AXIS. BUT LOW LEVEL FLOW IS EXPECTED TO
BECOMING EASTERLY OR ENE BEHIND THE FRONT AS IT TAKES ON A MORE
NW-SE ORIENTATION... GIVEN THE RAPID LOOSENING OF THE HEIGHT
GRADIENT ALOFT AS THE SOUTHERN PORTION OF THE TROUGH WEAKENS. THIS
SHOULD SERVE TO HOLD CLOUDS IN LONGER ACROSS THE SRN AND ERN CWA
THROUGH MUCH OF SUNDAY... WITH LINGERING LIGHT RAIN POSSIBLE IN THE
FAR SOUTHEAST WELL INTO THE DAY. AGAIN... CONFIDENCE IN THIS
SCENARIO IS NOT TERRIBLY HIGH. WILL HOLD ONTO RAIN CHANCES MAINLY IN
THE SOUTHEAST A LITTLE LONGER INTO THE DAY. COLD AIR ADVECTION WILL
NOT BEGIN IN EARNEST UNTIL LATE IN THE DAY... ALTHOUGH THE EASTERLY
FLOW MAY ALLOW FOR LITTLE HEATING IN THE SE SECTIONS WITH TEMPS
POTENTIALLY HOLDING IN THE 70S AREAWIDE. HAVE TRIMMED A DEGREE OR
TWO OFF HIGHS... TO RANGE FROM 76 TO 80. EXPECT SCATTERED CLOUDS TO
HOLD ON OVERNIGHT ESPECIALLY IN CENTRAL/ERN PARTS OF THE FORECAST
AREA GIVEN EXPECTED MOISTURE TRAPPED BENEATH THE SUBSIDENCE
INVERSION ALOFT WITH LITTLE OPPORTUNITY FOR DISPERSION VERTICALLY OR
HORIZONTALLY. LOWS AROUND 50 NORTH TO NEAR 59 SOUTH. -GIH
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...
AN AMPLIFIED...BUT RELATIVELY PROGRESSIVE UPPER LEVEL FLOW WILL LEAD
TO RIDGING OVER THE EASTERN US WHILE A SHORTWAVE MOVING ONSHORE OF
THE WEST COAST TODAY TRACKS ACROSS THE CENTRAL US MONDAY AND
TUESDAY. AT THE SURFACE...HIGH PRESSURE WILL SETTLE OVER EASTERN
CANADA AND EXTEND DOWN THE EAST COAST. THE MAIN FORECAST CHALLENGE
IS THE AFOREMENTIONED SHORTWAVE...WITH MEDIUM RANGE MODEL GUIDANCE
SHOWING SIGNIFICANTLY DIFFERENT IMPACTS. THE ECMWF PUSHES THE
SHORTWAVE THROUGH THE RIDGE...DRAWING MORE MOISTURE NORTH FROM THE
GULF OF MEXICO ATOP THE SURFACE RIDGE...LEADING TO MORE CLOUD
COVER/PRECIP...AND EVENTUALLY CYCLOGENESIS ALONG THE STALLED FRONTAL
ZONE OFF THE SOUTHEAST COAST. THE GFS LIFTS THE SHORTWAVE
TOWARD THE GREAT LAKES AND LEAVES THE SOUTHEAST US DRY. WPC PREFERS
AN ECMWF-LIKE SOLUTION BASED AN ENSEMBLE GUIDANCE...WHICH WOULD
STILL KEEP MOST PRECIP SOUTH OF THE CWA AND LIMIT A COLD AIR DAMMING
SCENARIO. WILL INDICATE A CHANCE POP ACROSS SOUTHERN COUNTIES ON
WEDNESDAY...WITH JUST A SLIGHT CHANCE TO THE NORTH. HIGHS WILL
GENERALLY BE AT OR BELOW NORMAL FOR MOST OF THE WEEK...COOLEST
TUESDAY/WEDNESDAY WITH ADDED CLOUD COVER...AND SHOULD RISE BACK TO
AROUND OR JUST ABOVE NORMAL BY THE END OF THE WEEK AHEAD OF THE NEXT
COLD FRONT.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1015 AM SATURDAY...
IFR/LIFR CEILINGS WEST OF U.S. 1...MAINLY WEST OF KRDU TOWARD THE
TRIAD...SHOULD LIFT TO VFR THIS MORNING. VISIBLE SATELLITE IMAGERY
SHOWS A SLOW EROSION OF THE LOW CLOUDS UNDERNEATH THE HIGH CLOUDS.
ELSEWHERE...WITH A WEAK WARM FRONTAL ZONE SITTING OVER CENTRAL NC...
CIGS/VSBYS AT RDU/FAY WILL VARY BETWEEN MVFR AND VFR...WITH VFR
CONDITIONS DOMINANT BY 16Z. WIDESPREAD RAIN AND A FEW STORMS SHOULD
AFFECT INT/GSO BETWEEN 20Z AND 03Z THIS EVENING...AT RDU FROM 21Z
UNTIL AROUND 05Z...AND AT RWI/FAY AFTER 22Z THROUGH THE END OF THE
TAF VALID PERIOD. CIGS WITHIN THESE SHOWERS AND ISOLATED STORMS
SHOULD VARY BETWEEN MVFR AND VFR WITH MOSTLY MVFR VSBYS. CIGS SHOULD
START TO DROP BACK TO MVFR/IFR STARTING BETWEEN 03Z AND 06Z JUST
BEHIND THE FRONT...LASTING THROUGH 12Z SUNDAY MORNING.
LOOKING BEYOND 12Z SUNDAY MORNING...CIGS ARE EXPECTED TO REBOUND TO
VFR SLOWLY WEST TO EAST SUNDAY AS THE FRONT PUSHES EASTWARD...
ALTHOUGH IMPROVEMENT MAY NOT REACH FAY UNTIL AFTER 18Z SUNDAY AS A
FEW MODELS HAVE RAIN HOLDING IN ACROSS OUR SOUTHEAST WELL INTO THE
DAY. OTHERWISE...VFR CONDITIONS SHOULD DOMINATE FROM SUNDAY NIGHT
THROUGH WEDNESDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH WITH DRY
AIR MOVING IN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...DJF/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...DJF/HARTFIELD
AREA FORECAST DISCUSSION
NWS PORTLAND OR
255 AM PDT SAT SEP 21 2013
.SYNOPSIS...ADDITIONAL RAIN SHOWERS WILL CONTINUE THROUGH SATURDAY
WITH PERHAPS A FEW LIGHTNING STRIKES SCATTERED ABOUT NORTHWEST
OREGON. A STRONGER FRONT WILL BRING WINDY CONDITIONS TO THE
COAST...BREEZY CONDITIONS INLAND...AND ANOTHER ROUND OF WIDESPREAD
RAIN TO THE AREA SUNDAY. EXPECT COOL TEMPERATURES AND PERIODS OF
SHOWERS FOR THE FIRST HALF OF NEXT WEEK. DRIER CONDITIONS LOOK IN
STORE FOR THE SECOND HALF OF THE WORK WORK.
&&
.SHORT TERM...INFRARED SATELLITE IMAGERY EARLY THIS MORNING REVEALS
THE STRETCHING COLD FRONT THAT BROUGHT RAIN SHOWERS TO THE REGION
EARLIER THIS AFTERNOON AND EVENING IS NOW WELL EAST OF THE CASCADE
CREST. ALSO...A CLUSTER OF COOLING CLOUD TOPS CURRENTLY RESIDES JUST
OFF THE SOUTHWEST OREGON AND NORTHERN CALIFORNIA COASTS WITH A DECENT
AMOUNT OF LIGHTNING STRIKES OCCURRING OVERNIGHT IN THIS REGION.
LIGHTNING HAS BEEN OBSERVED OFFSHORE ABOUT AS FAR NORTH AS TILLAMOOK.
BASED ON SATELLITE EXTRAPOLATION...THE BULK OF THE CONVECTION LOOKS
LIKE IT WILL FLIRT WITH THE COAST AND OUR SOUTHERN INTERIOR ZONES
THIS MORNING AS MOST OF THE CONVECTION SLIDES EASTWARD INTO MEDFORDS
CWA. HRRR AND EVEN THE GLOBAL MODELS SUGGEST CONVECTION WILL BE MUCH
MORE LIMITED NORTH AND EAST OF SALEM TODAY WHEN COMPARED TO POINTS
SOUTH AND WEST. THIS SEEMS PLAUSIBLE GIVEN THE TRACK OF THE 500MB
COLD POOL. HOWEVER...CANNOT RULE OUT A THUNDERSTORM OR TWO NORTH AND
EAST OF SALEM DURING PEAK HEATING SO IT WAS RETAINED FOR THE
AFTERNOON HOURS.
BRIEF SHORTWAVE RIDGING SATURDAY NIGHT WILL CAUSE SHOWERS TO DIE AND
BECOME MUCH MORE ISOLATED IN NATURE. THE BREAK IN THE WET WEATHER
WILL BE SHORT LIVED HOWEVER...AS A SHORTWAVE TROUGH DIVES
SOUTHEASTWARD OUT OF THE GULF OF ALASKA. STRONG UPPER LEVEL SUPPORT
WILL ALLOW AN ORGANIZED FRONT TO MOVE SOUTHEASTWARD ACROSS THE AREA
SUNDAY. ISENTROPIC LIFT AHEAD OF THIS FRONT WILL PRODUCE WIDESPREAD
RAIN...LIKELY IN EXCESS OF AN INCH ACROSS THE COAST RANGE...WITH UP
TO A HALF INCH FOR THE WILLAMETTE VALLEY SUNDAY AFTERNOON AND
EVENING.
EXPECT WINDS TO INCREASE AREA WIDE SUNDAY MORNING AS PRESSURE
GRADIENTS INCREASE. MODELS CONTINUE TO DISAGREE ON THE POTENTIAL FOR
HIGH WIND CRITERIA FOR THE COAST. THE NAM APPEARS MORE FAVORABLE
WHILE THE GFS IS SLOWLY TRENDING WEAKER AND HAS WINDS 10 TO 15 KTS
LESS THAN THE NAM AT 925MB AND 850MB. SO FOR NOW...WILL HOLD OFF
ON A HIGH WIND WATCH FOR THE COAST...AND HIGHLIGHT THE FIRST OF THE
SEASON WIND EVENT FOR THE COAST WITH AN SPS. EVEN ISOLATED POWER
OUTAGES SEEM LIKE A DECENT BET FOR THE WILLAMETTE VALLEY WHERE 30 TO
35 MPH WINDS WILL LIKELY TOPPLE A FEW TREES GIVEN MANY AREAS HAVE
NOT EXPERIENCED ANY WINDS OF SIGNIFICANCE IN MONTHS.
ONCE THE FRONT SLIDES SOUTHEAST OF THE AREA SUNDAY EVENING...STRONG
ZONAL FLOW AND LOW LEVEL INSTABILITY SHOULD KEEP SHOWERS GOING
SUNDAY NIGHT INTO MONDAY. HOWEVER...THE COLD AIR ALOFT AND UPPER
LEVEL DYNAMICS LOOK TO REMAIN WELL TO OUR NORTH...WHICH SHOULD
RESULT IN SHOWERS HAVING AN INCREASINGLY HARD TIME MAKING IT INTO
THE WILLAMETTE VALLEY DURING THIS TIME. AS A RESULT...KEPT THE
HIGHEST CHANCES FOR RAIN ALONG THE COAST...CASCADES AND OUR FAR
NORTHERN ZONES.
THE MAIN GULF OF ALASKA TROUGH AND A SECONDARY COLD FRONT WILL
EVENTUALLY SWING THROUGH THE REGION TUESDAY. THIS SHOULD BRING A
BETTER THREAT FOR SHOWERS AREA WIDE SO POPS WERE NUDGED UPWARD
ACCORDINGLY. IN ADDITION...SNOW LEVELS WILL ONCE AGAIN DIP INTO THE
6KFT RANGE...IF NOT A TOUCH LOWER. /NEUMAN
.LONG TERM...MONDAY THROUGH FRIDAY...ONSHORE FLOW AHEAD OF THE COLD
UPPER TROUGH OFF THE B.C. COAST SHOULD RESULT COOL AND BREEZY
CONDITIONS...ALONG WITH ADDITIONAL ROUNDS OF SHOWERS MONDAY AND
TUESDAY AS AN UPPER LEVEL TROUGH DROPS INTO THE PACIFIC NORTHWEST.
THE UPPER LOW WILL SHIFT SOUTH AND EAST OF THE AREA THROUGH THE DAY
ON WEDNESDAY ALLOWING SHOWERS TO DIMINISH...THOUGH CLOUDS LINGER AS
WE REMAIN IN CYCLONIC FLOW ALOFT. EXPECT AN UPPER LEVEL RIDGE WILL
BE OFFSHORE ON WEDNESDAY EVENING AND ATTEMPT TO SLOWLY PUSH ONSHORE.
THE FLOW TURNS NORTH TO NORTHEASTERLY WHICH WILL ALLOW THE AREA TO
DRY OUT THROUGH AT LEAST EARLY FRIDAY. EXPECT SOME OF THE COOLEST
OVERNIGHT LOWS OF THE SEASON DURING THE LATTER HALF OF THE EXTENDED
PERIOD...AND WE MAY SEE SOME MORNING LOW CLOUDS AND FOG. KMD/ROCKEY
&&
.AVIATION...A MOIST AND UNSTABLE AIRMASS WILL BRING A THREAT OF
SHOWERS AND THUNDERSTORMS TODAY...WITH VARYING FLIGHT CONDITIONS.
EXPECT VFR CONDITIONS TO BE THE MOST PREVALENT...BUT MVFR CONDITIONS
ARE LIKELY TO OCCUR AT TIMES THROUGHOUT NW OREGON. COASTAL AIRPORTS
ARE LIKELY TO SEE THE MOST TIME WITH MVFR CONDITIONS HOWEVER. IFR
CIGS AT KONP EARLY THIS MORNING ARE LIKELY TO GIVE WAY TO VFR OR
MVFR CONDITION LATE THIS MORNING...ESPECIALLY AFTER 18Z.
AIR MASS BEGINS TO STABILIZE AFTER 02Z AS THE UPPER TROUGH PASSES
WITH VFR CONDITIONS LIKELY TO DOMINATE IN THE EVENING BETWEEN 02Z
AND 08Z. EXPECT A RETURN TO MVFR CONDITIONS AFTER 08Z MOST AREAS AS
AIR MASS STABILIZES.
KPDX AND APPROACHES...VFR CONDITIONS LIKELY TO PREVAIL TODAY INTO
THE EVENING. HOWEVER...MVFR CIGS ARE LIKELY TO OCCUR SPORADICALLY
TODAY...ESPECIALLY AS SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP.
&&
.MARINE...WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA
THROUGH THIS EVENING AS A TROUGH OF LOW PRES MOVES ACROSS THE
WATERS. SEAS ALSO WILL SUBSIDE SOME...GOING UNDER 10 FT BY THE
AFTERNOON.
WINDS EXPECTED TO RAMP UP LATE TONIGHT AND SUN AHEAD OF AN OCCLUDED
FRONT THAT IS EXPECTED TO MOVE E ACROSS THE COASTAL WATERS SUN
AFTERNOON. WILL CONTINUE WITH THE GALE WATCH FOR THE OUTER WATERS
SUN AS STRONG PRES GRADIENTS PRECEDE THE FRONT. COMPUTER MODELS
HOWEVER INDICATE SOME WEAKENING OF THE FRONT AS IT APPROACHES THE
COAST AT THE END OF THE DAY...AND WITH WINDS AHEAD OF THE FRONT
BLOWING A LITTLE OFFSHORE IT IS NOT CLEAR THAT GALE FORCE WINDS WILL
EXTEND INTO THE INNER WATERS...ALTHOUGH IT IS NOT OUT OF THE
QUESTION EITHER. STEEP SHORT PERIOD SEAS WILL BUILD WITH THE WINDS
SUN...THEN A LONGER PERIOD WESTERLY SWELL WILL BUILD SUN NIGHT AND
MON...BRINGING SEAS TO AROUND 15 FT MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO
60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
10 AM PDT THIS MORNING.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM
THIS AFTERNOON TO 8 PM PDT THIS EVENING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1047 AM CDT SAT SEP 21 2013
.UPDATE...
MID LEVEL TROUGH AXIS HAS SHIFTED EAST INTO MI/IN AS SURFACE HIGH
PRESSURE PUSHES IN BEHIND IT. LOW STRATUS HAVE MOVED IN FROM THE
NORTHWEST. EXPECT CLOUDY SKIES THROUGH MID AFTERNOON THEN CLEARING
FROM WEST TO EAST PER THE 13Z HRRR WHICH HAS PERFORMED WELL WITH
THE CURRENT TREND.
&&
.AVIATION/18Z TAFS/...
INITIAL CUMULUS DEVELOPMENT IS MVFR IN SPOTS THIS MORNING...BUT
DAYTIME MIXING WILL HELP TO RAISE CEILINGS TO VFR BY 18Z. CIGS
WILL LIKELY SCATTER BY LATE AFTERNOON...WITH MUCH LESS CLOUDS
EXPECTED TONIGHT INTO SUNDAY UNDER HIGH PRESSURE.
&&
.PREV DISCUSSION... /ISSUED 308 AM CDT SAT SEP 21 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.
SCATTERED CLOUDS THIS MORNING WITH LOWEST BASES AROUND THREE
THOUSAND FEET WILL CONTINUE TO LINGER OVER THE AREA THROUGH THE
AFTERNOON. HIGH PRESSURE WILL BUILD OVER THE AREA SATURDAY AND
WILL BE CENTERED OVER LAKE SUPERIOR SUNDAY MID-DAY.
FOR TONIGHT...HIGH PRESSURE WITH MOSTLY CLEAR SKIES AND LIGHT
WINDS WILL ALLOW TEMPERATURES TO RAPIDLY DROP TO MIDDLE 40S ALONG
LAKE MICHIGAN SHORELINE...TO UPPER 30S WELL INLAND. EXPECT PATCHY
FROST IN LOW-LYING AREAS SHORTLY BEFORE SUNRISE IN INLAND COUNTIES
NORTH AND WEST OF MADISON...AND ALSO IN THE WISCONSIN RIVER VALLEY.
SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
SHORT TERM MODELS IN GOOD AGREEMENT WITH FEATURES DURING THIS
TIME. HIGH PRESSURE SLIDES SOUTHEAST ACROSS THE WESTERN AND
CENTRAL GREAT LAKES REGION DURING THIS PERIOD. A 500MB RIDGE ALSO
MOVES EAST ACROSS THE REGION SUNDAY THROUGH MONDAY...WITH A
SHORTWAVE TROUGH MOVING INTO IOWA AND MINNESOTA MONDAY NIGHT.
QUIET WEATHER IS EXPECTED SUNDAY THROUGH MONDAY NIGHT.
FAVORABLE DELTA T VALUES WITH ONSHORE WINDS SUNDAY MAY BRING A FEW
CLOUDS...THOUGH MOISTURE IS MEAGER. THE SHORTWAVE TROUGH MONDAY
NIGHT IS POTENT...BUT THERE IS LITTLE IN THE WAY OF MOISTURE PER
AREA FORECAST SOUNDINGS.
925MB TEMPERATURE TRENDS SUGGEST HIGHS IN THE 60S SUNDAY AND
MONDAY...A BIT MILDER ON MONDAY WITH A SLIGHTLY WARMER AIRMASS.
LOWS MAY DROP INTO THE UPPER 30S IN LOW SPOTS SUNDAY NIGHT WITH
RADIATIONAL COOLING CONDITIONS...THOUGH MOST OF THE AREA WILL BE
IN THE 40S. MILDER MID TO UPPER 40S MONDAY NIGHT ARE EXPECTED WITH
CONTINUED WARM AIR ADVECTION PER GFS/ECMWF.
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS MEDIUM.
GFS/ECMWF ARE SHOWING SOME DIFFERENCES DURING THIS PERIOD. THE GFS
BRINGS THE POTENT 500MB SHORTWAVE TROUGH THROUGH THE REGION
TUESDAY...WITH THE ECMWF DELAYING IT UNTIL TUESDAY NIGHT. BOTH
MODELS KEEP THE AREA DRY...AS AIRMASS REMAINS QUITE DRY PER AREA
FORECAST SOUNDINGS. NEAR NORMAL TEMPERATURES ARE EXPECTED.
500MB RIDGE CROSSES THE AREA WEDNESDAY...WITH FLOW BECOMING
SOUTHWESTERLY WEDNESDAY NIGHT INTO FRIDAY. HIGH PRESSURE TO THE
EAST OF THE AREA WILL KEEP DRY CONDITIONS GOING FOR WEDNESDAY INTO
THURSDAY. WARM AIR ADVECTION KICKING IN THURSDAY WILL BRING ABOVE
NORMAL TEMPERATURES INTO THE REGION.
GFS THEN BRINGS COLD FRONT EASTWARD INTO THE REGION THURSDAY
NIGHT AND FRIDAY...WITH THE ECMWF SLOWER AND KEEPING THE AREA DRY
DURING THIS TIME. GIVEN THE DIFFERENCES...WILL USE CONSENSUS POPS
AND TEMPERATURES FOR THURSDAY NIGHT INTO FRIDAY.
AVIATION/12Z TAFS/...
VFR CONDITIONS WITH LIGHT WINDS EXPECTED THROUGH THE WEEKEND.
MARINE...
LIGHT NORTHWEST WINDS TODAY BECOME NORTHEAST SUNDAY. WAVES AND
WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH
THE WEEKEND. MONDAY THROUGH THURSDAY...SOUTHERLY WINDS AND MOSTLY
SUNNY SKIES WITH NO SIGNIFICANT WEATHER OR SMALL CRAFT ADVISORY
CONDITIONS EXPECTED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...SM/DDV
TODAY/TONIGHT AND AVIATION/MARINE...SLB
SUNDAY THROUGH FRIDAY...WOOD
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1050 AM PDT SAT SEP 21 2013
.DISCUSSION...AS OF 08:43 AM PDT SATURDAY...IMPRESSIVE RAINFALL
NUMBERS ALREADY IN THE SANTA CRUZ MOUNTAINS AND NORTH
BAY...UP TO THREE QUARTERS OF AN INCH AT MOUNT SAINT HELENA.
OROGRAPHIC EFFECTS STRONGLY IN FORCE AT TIME IN WARM ADVECTIVE
SECTOR OF APPROACHING BAROCLINIC ZONE.
MODELS STRUGGLING WITH PRECIP AMOUNTS WITH 12Z NAM
UNDER FORECASTING AMOUNTS. PREFER HRRR SHORT TERM FORECAST THOUGH
TIMING HAS BEEN A LITTLE BIT SLOW WITH MODEL. 00Z ECMWF AND HRRR
APPEAR TO HAVE THE MOST REALISTIC SOLUTIONS WITH QPF.
INITIAL FRONTAL BOUNDARY HAS WASHED OUT OVER MONTEREY COUNTY WITH
MAIN BOUNDARY SHOWING CLOUD TOP COOLING AND DEVELOPMENT AS IT
MOVES INTO NORTH BAY. RAINFALL SHOULD SPREAD EAST AND SOUTHWARD
INTO THE BAY AREA THROUGH THE REST OF THE MORNING. APPEARS TO BE
SIGNIFICANT CONVECTION WITH OFFSHORE BOUNDARY...SO INCLUDED SLIGHT
CHANCE THUNDERSTORMS ACROSS MOST OF CWFA DOWN TO ABOUT MONTEREY.
PRECIPITATION WITH FRONTAL BOUNDARY WILL MOVE SOUTH INTO COASTAL
MONTEREY COUNTY THIS AFTERNOON...THOUGH SYSTEM WILL GRADUALLY
WEAKEN. BOUNDARY EXPECTED TO MOVE EAST AND SOUTH OF THE AREA BY
EVENING WITH RAPID CLEARING FROM NORTHWEST TO SOUTHEAST.
MADE SOME SIGNIFICANT UPDATES IN TODAYS FORECAST PERIOD WITH
REGARDS TO QPF AND POPS...INCREASING AMOUNTS AS RADAR AND
SATELLITE IMAGERY INDICATE DYNAMIC SYSTEM APPROACHING COAST.
LOOKING AT CONVECTIVE NATURE OF CELLS OFFSHORE ALREADY SHOWING ON
RADAR...WOULD NOT BE SURPRISED TO SEE A FEW HEAVIER SHOWERS AND
EVEN A THUNDERSTORM BY AFTERNOON.
&&
.PREV DISCUSSION...AS OF 3:39 AM PDT SATURDAY...SHOWER ACTIVITY IS
CONTINUING ACROSS THE NORTH BAY EARLY THIS MORNING WITH RAIN
TOTALS SO FAR FROM ABOUT 0.10 TO 0.30 FOR MARIN AND SONOMA
COUNTIES. IN GENERAL ONLY SPOTTY PRECIP HAS MADE IT SOUTH OF THE
GOLDEN GATE SO FAR WITH A FEW HUNDREDTHS IN THE HILLS OF SAN
MATEO AND SANTA CRUZ COUNTY. WERE STILL IN THE WARM SECTOR OF THE
SYSTEM WITH SOUTHERLY WINDS AT THE BUOYS AND OVER LAND KEEPING
OVERNIGHT TEMPERATURES FROM THE UPPER 50S TO MID 60S.
A POTENT SHORTWAVE IS JUST ABOUT TO PASS OVER 38N/130W AND IS
POISED TO TAKE AIM ON THE GREATER BAY AREA LATER THIS MORNING AND
AFTERNOON AS THE UPPER TROUGH AXIS PASSES OVERHEAD. LATEST MODEL
TRENDS HAVE TRENDED SLIGHTLY WETTER AND EXPECT SHOWER ACTIVITY TO
INCREASE FROM MID-MORNING THROUGH EARLY AFTERNOON AS IT SHIFTS
SOUTHWARD FROM THE NORTH BAY...THROUGH THE GREATER BAY AREA AND
THEN DISSIPATES WITH LITTLE OR NO PRECIP SOUTH OF MONTEREY.
HIGHEST RAIN TOTALS WILL BE IN THE NORTH BAY WITH A TENTH OF AN
INCH OR SO FOR THE BAY AREA TAPERING TO A FEW HUNDREDTHS AROUND
MONTEREY BAY. GIVEN STRENGTH OF SHORTWAVE AND STEEP LAPSE RATES
ALOFT AS WELL AS HIGH SURFACE DEWPOINTS WILL KEEP THE THREAT OF
THUNDERSTORMS GOING IN THE NORTH BAY TODAY.
SHOWER ACTIVITY SHOULD RAPIDLY WIND DOWN BY EARLY EVENING AND END
BY SUNSET AS THE VORT MAX SHIFTS EASTWARD AND SOLAR HEATING ENDS.
AFTER A CHILLY START SUNDAY LOOKS TO BE A NICE DAY WITH CRYSTAL
BLUE SKIES IN THE WAKE OF THE UPPER TROUGH AND SEASONABLY MILD
TEMPS FROM THE 60S COAST TO 70S INLAND.
NO BIG WEATHER CHANGES FOR MONDAY WITH MOSTLY CLEAR AND SEASONABLE
WEATHER FORECAST.
NEXT SHORTWAVE APPROACHES NORCAL BY TUESDAY BUT ANY PRECIP WILL
STAY EAST OF THE BAY AREA AS THE MAIN SHORTWAVE SHIFTS WELL
INLAND. THE PATTERN WILL PRODUCE SOME BREEZY CONDITIONS LATER
TUESDAY INTO WEDS. SURFACE PATTERN WILL THEN SHIFT A THERMAL
TROUGH TOWARDS THE COAST WEDS NIGHT INTO THURSDAY WITH A TIGHT
PRESSURE GRADIENT SETTING UP ACROSS NORCAL. MODELS HAVE BEEN
KEYING IN ON THE 06-12Z THURSDAY TIME FRAME FOR SOME STRONGER
NORTH TO NORTHEAST WINDS. WILL CONTINUE TO MONITOR THAT TREND AND
WILL HAVE TO SEE HOW MUCH DRYING OCCURS AFTER TODAYS RAIN BEFORE
THE WINDS BLOW AS TO HOW THAT WILL IMPACT FIRE WEATHER CONDITIONS.
LIVE FUEL MOISTURES WONT BE IMPACTED BY TODAYS RAIN AS THE PLANTS
ARE DORMANT.
&&
.AVIATION...AS OF 10:45 AM PDT SATURDAY...FORECAST CONFIDENCE IS
REMAINING LOW. A MID LEVEL TROUGH AXIS PUSHING TOWARDS THE AREA
CURRENTLY BRINGING LOTS OF SHOWERS AND EVEN OCCASIONAL MODERATE TO
HEAVY RAIN AT TERMINALS. CEILINGS HAVING A DIFFICULT TIME FALLING
BELOW VFR DESPITE RAINFALL BUT SOME OCCASIONAL IFR OBSERVED IN
HEAVIER RAIN SHOWERS. EXPECT RAIN THREAT TO TAPER OFF AT TERMINALS
BY 00Z SUN AND WIND SHIFT TO NORTHWEST SHORTLY THEREAFTER.
GENERALLY VFR BUT SOME MVFR/IFR CIGS OVERNIGHT AT TERMINALS. LOW
PROBABILITY OF THUNDER THIS MORNING AND EARLY AFTERNOON SO WILL
NOT CARRY MENTION IN TAF.
VICINITY OF KSFO...DESPITE HEAVY RAIN AT TIMES...CIGS REMAIN VFR.
WILL KEEP THIS TREND WITH GRADUAL DECREASE INTO MVFR CATEGORY.
BAND OF MODERATE TO HEAVY RAIN WILL EXIT THE AREA BY 23Z AND WIND
SHIFT TO WEST WILL OCCUR SHORTLY THEREAFTER. MAY BE BRIEFLY GUSTY
WITH WEST WIND SHIFT. CIGS WILL BOUNCE AROUND MVFR TO VFR
OVERNIGHT WITH SOME INDICATION OF A PERIOD OF MVFR CIGS AROUND
SUNRISE BUT NOT A GOOD CONFIDENCE IN THE FORECAST OVERALL.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR THIS MORNING WILL FALL INTO MVFR
CATEGORY AS CLOUDINESS AND SHOWERS APPROACH SLOWLY FROM THE
NORTHWEST. WILL EXPECT MVFR/IFR CONDITIONS AFTER 21-23Z SAT AND
EXPECTING PERSISTENT IN THAT RANGE THROUGH 12Z SUN. WEST WIND
SHIFT EARLY SUNDAY MORNING BUT LOW CONFIDENCE IN CIG IMPROVEMENT.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
&&
$$
PUBLIC FORECAST: KBB
AVIATION/MARINE: JOHNSON
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
903 AM PDT SAT SEP 21 2013
.DISCUSSION...AS OF 08:43 AM PDT SATURDAY...IMPRESSIVE RAINFALL
NUMBERS ALREADY IN THE SANTA CRUZ MOUNTAINS AND NORTH
BAY...UP TO THREE QUARTERS OF AN INCH AT MOUNT SAINT HELENA.
OROGRAPHIC EFFECTS STRONGLY IN FORCE AT TIME IN WARM ADVECTIVE
SECTOR OF APPROACHING BAROCLINIC ZONE.
MODELS STRUGGLING WITH PRECIP AMOUNTS WITH 12Z NAM
UNDER FORECASTING AMOUNTS. PREFER HRRR SHORT TERM FORECAST THOUGH
TIMING HAS BEEN A LITTLE BIT SLOW WITH MODEL. 00Z ECMWF AND HRRR
APPEAR TO HAVE THE MOST REALISTIC SOLUTIONS WITH QPF.
INITIAL FRONTAL BOUNDARY HAS WASHED OUT OVER MONTEREY COUNTY WITH
MAIN BOUNDARY SHOWING CLOUD TOP COOLING AND DEVELOPMENT AS IT
MOVES INTO NORTH BAY. RAINFALL SHOULD SPREAD EAST AND SOUTHWARD
INTO THE BAY AREA THROUGH THE REST OF THE MORNING. APPEARS TO BE
SIGNIFICANT CONVECTION WITH OFFSHORE BOUNDARY...SO INCLUDED SLIGHT
CHANCE THUNDERSTORMS ACROSS MOST OF CWFA DOWN TO ABOUT MONTEREY.
PRECIPITATION WITH FRONTAL BOUNDARY WILL MOVE SOUTH INTO COASTAL
MONTEREY COUNTY THIS AFTERNOON...THOUGH SYSTEM WILL GRADUALLY
WEAKEN. BOUNDARY EXPECTED TO MOVE EAST AND SOUTH OF THE AREA BY
EVENING WITH RAPID CLEARING FROM NORTHWEST TO SOUTHEAST.
MADE SOME SIGNIFICANT UPDATES IN TODAYS FORECAST PERIOD WITH
REGARDS TO QPF AND POPS...INCREASING AMOUNTS AS RADAR AND
SATELLITE IMAGERY INDICATE DYNAMIC SYSTEM APPROACHING COAST.
LOOKING AT CONVECTIVE NATURE OF CELLS OFFSHORE ALREADY SHOWING ON
RADAR...WOULD NOT BE SURPRISED TO SEE A FEW HEAVIER SHOWERS AND
EVEN A THUNDERSTORM BY AFTERNOON.
&&
.PREV DISCUSSION...AS OF 3:39 AM PDT SATURDAY...SHOWER ACTIVITY IS
CONTINUING ACROSS THE NORTH BAY EARLY THIS MORNING WITH RAIN
TOTALS SO FAR FROM ABOUT 0.10 TO 0.30 FOR MARIN AND SONOMA
COUNTIES. IN GENERAL ONLY SPOTTY PRECIP HAS MADE IT SOUTH OF THE
GOLDEN GATE SO FAR WITH A FEW HUNDREDTHS IN THE HILLS OF SAN
MATEO AND SANTA CRUZ COUNTY. WERE STILL IN THE WARM SECTOR OF THE
SYSTEM WITH SOUTHERLY WINDS AT THE BUOYS AND OVER LAND KEEPING
OVERNIGHT TEMPERATURES FROM THE UPPER 50S TO MID 60S.
A POTENT SHORTWAVE IS JUST ABOUT TO PASS OVER 38N/130W AND IS
POISED TO TAKE AIM ON THE GREATER BAY AREA LATER THIS MORNING AND
AFTERNOON AS THE UPPER TROUGH AXIS PASSES OVERHEAD. LATEST MODEL
TRENDS HAVE TRENDED SLIGHTLY WETTER AND EXPECT SHOWER ACTIVITY TO
INCREASE FROM MID-MORNING THROUGH EARLY AFTERNOON AS IT SHIFTS
SOUTHWARD FROM THE NORTH BAY...THROUGH THE GREATER BAY AREA AND
THEN DISSIPATES WITH LITTLE OR NO PRECIP SOUTH OF MONTEREY.
HIGHEST RAIN TOTALS WILL BE IN THE NORTH BAY WITH A TENTH OF AN
INCH OR SO FOR THE BAY AREA TAPERING TO A FEW HUNDREDTHS AROUND
MONTEREY BAY. GIVEN STRENGTH OF SHORTWAVE AND STEEP LAPSE RATES
ALOFT AS WELL AS HIGH SURFACE DEWPOINTS WILL KEEP THE THREAT OF
THUNDERSTORMS GOING IN THE NORTH BAY TODAY.
SHOWER ACTIVITY SHOULD RAPIDLY WIND DOWN BY EARLY EVENING AND END
BY SUNSET AS THE VORT MAX SHIFTS EASTWARD AND SOLAR HEATING ENDS.
AFTER A CHILLY START SUNDAY LOOKS TO BE A NICE DAY WITH CRYSTAL
BLUE SKIES IN THE WAKE OF THE UPPER TROUGH AND SEASONABLY MILD
TEMPS FROM THE 60S COAST TO 70S INLAND.
NO BIG WEATHER CHANGES FOR MONDAY WITH MOSTLY CLEAR AND SEASONABLE
WEATHER FORECAST.
NEXT SHORTWAVE APPROACHES NORCAL BY TUESDAY BUT ANY PRECIP WILL
STAY EAST OF THE BAY AREA AS THE MAIN SHORTWAVE SHIFTS WELL
INLAND. THE PATTERN WILL PRODUCE SOME BREEZY CONDITIONS LATER
TUESDAY INTO WEDS. SURFACE PATTERN WILL THEN SHIFT A THERMAL
TROUGH TOWARDS THE COAST WEDS NIGHT INTO THURSDAY WITH A TIGHT
PRESSURE GRADIENT SETTING UP ACROSS NORCAL. MODELS HAVE BEEN
KEYING IN ON THE 06-12Z THURSDAY TIME FRAME FOR SOME STRONGER
NORTH TO NORTHEAST WINDS. WILL CONTINUE TO MONITOR THAT TREND AND
WILL HAVE TO SEE HOW MUCH DRYING OCCURS AFTER TODAYS RAIN BEFORE
THE WINDS BLOW AS TO HOW THAT WILL IMPACT FIRE WEATHER CONDITIONS.
LIVE FUEL MOISTURES WONT BE IMPACTED BY TODAYS RAIN AS THE PLANTS
ARE DORMANT.
&&
.AVIATION...AS OF 5:00 AM PDT SATURDAY...VERY TRICKY LOW
CONFIDENCE FORECAST TODAY AS CIGS HAVE BEEN ALL OVER THE PLACE SO
FAR TONIGHT. MODELS ARE IN GOOD AGREEMENT AND BRING RAIN TO THE
NORTH BAY AFTER 12Z AND DOWN TO ABOUT MONTEREY 18 TO 21Z. STILL AM
EXPECTING MOSTLY IFR TO LOW MVFR CONDITIONS THROUGH MOST OF THE
MORNING WITH GUSTS LIKELY DURING ANY SHOWERS. CONDITIONS IMPROVE
AFTER THE FRONTAL PASSAGE.
VICINITY OF KSFO...CURRENTLY AROUND VFR LEVELS BUT SHOULD DROP BACK
TO MVFR/IFR FOR MOST OF THE MORNING. RAIN CHANCES FROM 15 TO
AROUND 23Z WITH GUSTS POSSIBLE DURING ANY SHOWERS. SW WINDS
THIS MORNING WITH GUSTS TO 20KT BY AFTERNOON. EVEN STRONGER
WESTERLY WINDS BY THE EVENING. VFR RETURNS BY TONIGHT. LOW CONFIDENCE.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR SHOULD SWITCH TO MVFR BY LATER
THIS MORNING. RAIN FORECAST TO REMAIN NORTH OF MONTEREY BAY
ALTHOUGH ENOUGH OF A CHANCE IN THE FORECAST SO ADDED VCSH TO BOTH
TERMINALS. LOW TO MODERATE CONFIDENCE.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
&&
$$
PUBLIC FORECAST: KBB
AVIATION/MARINE: BELL
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FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
355 PM EDT SAT SEP 21 2013
.SYNOPSIS...
ISSUED AT 1022 AM EDT SAT SEP 21 2013
HIGH PRESSURE WILL BE OVER THE REGION THIS WEEKEND PROVIDING US
WITH A COOL WEEKEND. SUNNY TO MOSTLY CLOUDY IN AREAS TODAY WITH
HIGH TEMPERATURES ONLY IN THE LOWER 60S NEAR LAKE MICHIGAN TO THE
LOWER 70S NEAR THE OHIO RIVER. SKIES TONIGHT WILL BE MAINLY CLEAR
ALLOWING TEMPERATURES TO DROP DOWN INTO THE 40S. TOMORROW SKIES
WILL BE SUNNY WITH HIGH TEMPERATURES RANGING FROM THE LOWER 60S IN
SOUTHERN MICHIGAN TO AROUND 70 ALONG THE OHIO RIVER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 354 PM EDT SAT SEP 21 2013
BROKEN STRATOCU DECK IS CONTINUING TO EXPAND ACROSS THE AREA AS COLD
AIR ADVECTION CONTINUES. THE COLDEST PORTION OF THIS AIRMASS WILL
ADVECT OVERHEAD TONIGHT WHICH WILL ALLOW TEMPERATURES TO DROP INTO
THE MID 40S. THE EXCEPTION WILL BE IN WESTERN AREAS WHERE LAKE
EFFECT CLOUD COVER WILL KEEP TEMPERATURES IN THE UPPER 40S. WENT
WITH A BLEND OF THE BCSREF AND BCEURO FOR OVERNIGHT LOWS AS THEY
WERE BOTH ON THE WARMER SIDE OF GUIDANCE. HAVE ELECTED FOR OVERNIGHT
LOWS A FEW DEGREES HIGHER DUE TO CONCERN OF SCATTERED CLOUDCOVER
PERSISTING ACROSS THE AREA TONIGHT AS WELL AS SLIGHTLY HIGHER
FORECAST DEWPOINTS. STRATOCU DECK ACROSS WISCONSIN HAS BEEN VERY
PERSISTENT TODAY AND BOTH THE RAP AND HRRR SHOW LITTLE DISSIPATION
AS IT ADVECTS OUR WAY OVERNIGHT. ON THE OTHER HAND...THE LAST FEW
FRAMES OF VISIBLE SATELLITE MAY BE HINTING AT SOME DRY AIR
ENTRAINMENT ON THE WESTERN EDGE OF THIS DECK. RAP/HRRR/NAM ARE ALL
INDICATING POTENTIAL FOR LAKE EFFECT RAIN SHOWERS AFTER MIDNIGHT AS
A SHORTWAVE DROPS THROUGH MICHIGAN...BUT HAVE KEPT FORECAST DRY
GIVEN LOWERING/STRENGTHENING INVERSION...DRY AIR ABOVE 850 MB...AND
SHALLOW FORECAST CLOUD DEPTH.
SUNDAY WILL BE COOL AND MOSTLY SUNNY AS HIGH PRESSURE SLIDES ACROSS
THE GREAT LAKES AND CYCLONIC FLOW ALOFT COMES TO AN END. CU RULE
VALUES IN THE WEST INDICATE THE POTENTIAL FOR SOME LAKE EFFECT CLOUD
COVER FOR THE FIRST PORTION OF THE DAY...BUT EVEN THIS WILL COME TO
AN END BY MID DAY ONCE WARM AIR ADVECTION ARRIVES.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 354 PM EDT SAT SEP 21 2013
UPR LEVEL RIDGE OVER THE PLAINS THIS AFTN WILL MOVE EAST TO THE WRN
GRTLKS SUNDAY NIGHT. THIS RIDGE SHOULD BECOME NRLY STNRY OVER THE
GRTLKS MON-TUE AS A DEEP CUT-OFF LOW FORMS OVER SERN CANADA. STRONG
SHRTWV MOVG ONTO THE WEST COAST THIS AFTN IS EXPECTED TO MOVE EAST
TO THE MS VALLEY TUE. COMBINATION OF ENCOUNTER WITH STALLED RIDGE
AND SHEARING ASSOCIATED WITH ANOTHER STRONG SHRTWV MOVG INTO THE
MEAN WRN TROF WILL WEAKEN THE LEAD SHRTWV AS IT APPROACHES OUR AREA.
SHOULD BE SOME INCREASE IN MOISTURE/CLOUDINESS AS THIS SYSTEM MOVES
THROUGH THE AREA TUE NGT/WED BUT AIRMASS EXPECTED TO REMAIN STABLE
WITH RATHER WARM MID/UPR LEVELS SO KEPT FCST DRY THROUGH THIS
TIMEFRAME.
RIDGE SHOULD REBUILD OVER THE AREA THU-FRI AS THE NEXT STRONG SHRTWV
CURRENTLY LOCATED OVER THE GULF OF ALASKA MOVES ACROSS THE ROCKIES.
12Z MEDIUM RANGE MODELS CONT TO HAVE CONSIDERABLE DIFFERENCE ON
TIMING/EVOLUTION OF THE TROF BY SATURDAY WITH ECMWF SHEARING SYSTEM
NE ACROSS THE NRN PLAINS/UPR GRTLKS INTO MANITOBA/ONTARIO WHILE
GFS/GEFS MAINTAIN A STRONGER UPR TROF/SFC CDFNT MOVG EAST INTO THE
MID/UPR MS VALLEY. BOTH MODELS HAVE TRENDED TOWARD A MORE PERSISTENT
RIDGE NEXT WEEKEND ACROSS THE GRTLKS OVER THE PAST 24HRS SO PREFER
ECMWF FARTHER WEST SOLUTION IN THIS REGARD AND THUS KEPT FCST FOR
SAT DRY FOR NOW.
TEMPS SHOULD BE A BIT BLO NORMAL AT THE START OF THE PERIOD WITH
LOWS IN THE L-M40S AND HIGHS IN THE M-U60S MONDAY. A SLOW WARMING
TREND EXPECTED THROUGH THE WEEK AS UPR RIDGE BUILDS INTO THE AREA
WITH ABOVE NORMAL TEMPS MID-LATE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 152 PM EDT SAT SEP 21 2013
BREEZY NORTHWEST WINDS ARE USHERING A COOLER AIRMASS INTO THE AREA.
WITH COLD TEMPS ALOFT... BKN/OVC IFR STRATOCU DECK HAS DEVELOPED
THIS AFTERNOON AND WILL CONTINUE THROUGH THE EVENING. EXPECT THE
CLOUDS TO SCATTER OUT OVERNIGHT AT KFWA...BUT LAKE EFFECT CLOUDS
WILL KEEP CLOUD COVER MORE PERSISTENT AT KSBN. ALL CEILINGS EXPECTED
TO REMAIN IFR THROUGH THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR INZ003.
MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR LMZ043-046.
&&
$$
SYNOPSIS...LOTHAMER
SHORT TERM...BENTLEY
LONG TERM...JT
AVIATION...BENTLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1245 PM CDT SAT SEP 21 2013
.UPDATE...
ISSUED AT 1245 PM CDT SAT SEP 21 2013
VISIBLE SATELLITE INDICATES THE AREA OF STRATUS HAS PUSHED
SOUTHWARD INTO EXTREME NW IL. HOWEVER...THE WESTERN EDGE OF THE
STRATUS FROM EASTERN MN INTO EXTREME NORTHEAST IA WAS BEGINNING TO
ERODE AS HIGH PRESSURE BUILDS IN FROM THE PLAINS. SKIES SHOULD BE
PARTLY TO MOSTLY CLOUDY EARLY THIS AFTERNOON IN EXTREME NW IL BUT
THEN SKIES WILL BECOME MOSTLY SUNNY. ELSEWHERE ACROSS THE CWA ONLY
A FEW TO SCATTERED FLAT CUMULUS.
CURRENT TEMPERATURES RANGED FROM THE UPPER 50S TO UPPER 60S ON
TARGET FOR THE MID 60S TO LOWER 70S LATER THIS AFTERNOON.
UPDATE ISSUED AT 1050 AM CDT SAT SEP 21 2013
PLEASANT FALL-LIKE DAY IN PROGRESS WITH CURRENT TEMPERATURES IN
THE MID 50S TO LOWER 60S. THESE READINGS APPEAR ON TARGET FOR
AFTERNOON HIGHS IN THE MID 60S TO LOWER 70S.
I AM WATCHING AN AREA OF STRATUS ACROSS MUCH OF WI AND EASTERN MN
WHERE THE LOW LEVELS ARE QUITE MOIST. THESE CLOUDS ARE SPREADING
SOUTHWARD BUT ALSO WILL BE RUNNING INTO DRIER AIR. OUR NW IL
COUNTIES LOOK VULNERABLE TO HAVING AT LEAST PARTLY SUNNY SKIES AND
HAVE INCREASED THE SKY GRIDS FOR THAT AREA. ELSEWHERE SCATTERED
CUMULUS/STRATOCUMULUS EXPECTED.
&&
.SYNOPSIS...
ISSUED AT 302 AM CDT SAT SEP 21 2013
FRIDAYS COLD FRONT STRETCHED FROM THE JAMES BAY SOUTHWARD TO KDTW TO
KDAY TO KMKL WITH SURFACE HIGH PRESSURE STRETCHING FROM SOUTHERN MANITOBA
SOUTHWARD TO THE TEXAS PANHANDLE. COOL...DRY AIR CONTINUED TO DROP
SOUTHWARD INTO THE UPPER MIDWEST FROM SOUTHERN CANADA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CDT SAT SEP 21 2013
THE 500 HPA TROUGH AXIS HAS SHIFTED EASTWARD INTO CENTRAL ILLINOIS
AND WISCONSIN THIS MORNING WITH NORTHWEST FLOW ALOFT ACROSS THE
REGION. STRATUS WAS UPSTREAM OF THE REGION ACROSS EASTERN NORTH
DAKOTA AND WESTERN MINNESOTA. THIS AREA OF CLOUDS IS REPRESENTED
WELL BY 850 HPA RH. THE 00 UTC GFS AND ECMWF BOTH DEPICT THIS AREA
OF CLOUDS DISSIPATING OR GRAZING THE CORNER OF NORTHWEST ILLINOIS
LATER THIS MORNING WHILE THE RAP DEPICTS THE MOISTURE
OVERSPREADING THE REGION. THE RAP HAS TOO MUCH MOISTURE IN THE LOW
LEVELS AND WILL THUS KEEP CLOUD COVER DOWN ACROSS THE REGION THIS
MORNING. OTHERWISE HIGH PRESSURE WILL SLOW BUILD SOUTHWARD ACROSS
THE REGION DURING THE DAY ON SATURDAY. SKIES WILL BE MOSTLY SUNNY
WITH A FEW CU DEVELOPING. A PLEASANT DAY WITH HIGH TEMPERATURES
FROM THE MID 60S ALONG HIGHWAY 20 TO AROUND 70 ACROSS SOUTHEAST
IOWA AND NORTHWEST MISSOURI WHICH IS 10 DEGREES BELOW NORMAL FOR
MID SEPTEMBER.
HIGH PRESSURE WILL BE SITTING OVER THE REGION SATURDAY NIGHT INTO
SUNDAY MORNING WITH CLEAR SKIES AND STRONG RADIATIONAL COOLING. KEPT
LOW TEMPERATURES FOR SUNDAY MORNING THE SAME AS PREVIOUS SHIFTS. A
CHILLY MORNING ON SUNDAY WITH TEMPERATURES REMAINING BELOW NORMAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 302 AM CDT SAT SEP 21 2013
A CONSISTENTLY PLEASANT FALL WEATHER FORECAST IS IN STORE FOR SUNDAY
THROUGH THURSDAY...AS DRY WEATHER DOMINATES THE MIDWEST WEATHER.
THIS WILL INITIALLY BE THROUGH A COOL GREAT LAKES HIGH
PRESSURE...ONE THAT IS BUILDING IN TODAY. THE RESULTING WEATHER
ASSOCIATED WITH THIS HIGH WILL BE SEVERAL DAYS OF LIGHT EASTERLY
FLOW AT LOW LEVELS...AND VERY LARGE DIURNAL DAILY TRENDS. GUIDANCE
CONTINUES TO BE COOLING IN THE PAST FEW DAYS FOR SUNDAY THROUGH
TUESDAY...AND WE WILL CONTINUE TO FORECAST NEAR THE COOLER SIDE OF
OVERNIGHT LOWS...AND NEAR THE MEAN OF GUIDANCE HIGHS. THIS RESULTS
IN LOWS MAINLY IN THE LOWER 40S EAST TO UPPER 40S WEST SUNDAY
NIGHT...AND UPPER 40S/LOW 50S MONDAY NIGHT. SUNDAY THROUGH
TUESDAY...HIGHS WILL GRADUALLY INCREASE FROM THE LOWER 70S...TO MID
70S. IN ALL...VERY PLEASANT WEATHER.
A MOISTURE STARVED UPPER LOW WILL WEAKEN OF MOVE NORTHEAST IN THE
UPPER MIDWEST TUESDAY. OTHER THAN A BRIEF INCREASE IN MID AND HIGH
CLOUDS TUESDAY...AND AN INCREASE IN SOUTH WINDS...THIS SYSTEM WILL
OFFER NO CHANCE OF MEASURABLE RAIN. IT IS HERE WHEN THE TWO MAIN
EXTEND MODELS DIVERGE. BOTH THE GFS AND ECMWF DEVELOP A LARGE
SYNOPTIC CUT OFF LOW IN THE ROCKIES BY WEDNESDAY. THE DEEP MOISTURE
RETURN ON BOTH MODELS INCREASES BY LATE THURSDAY...BUT THE ECMWF
BRINGS THIS ENERGY OUT OF THE SOUTHWEST IN ONE LARGE LOW...WELL TO
THE NORTH...VS THE GFS BRINGING ENERGY OUT IN TWO WAVES. THUS...IT
IS FASTER INITIALLY...AS IT BRINGS THE FRONT TO EASTERN IOWA BY
THURSDAY NIGHT...BUT AS ANOTHER WAVE LIFTS OUT OF THE ROCKIES
FRIDAY...MOISTURE CONVERGES ALONG THE BOUNDARY NEARBY TO PRODUCE A
SIGNIFICANT RAIN EVENT. THE ECMWF AND ITS SINGLE QUICK COLD FROPA
OFFERS VERY LITTLE THREAT OF RAIN. SO...WE ARE LEFT WITH A BLENDED
MODEL OUTPUT OF CHANCE POPS ON DAY 7. BOTH THE GFS AND ECMWF HAVE
BEEN CONSISTENT IN THESE SCENARIOS...AND BOTH APPEAR POSSIBLE.
THUS...TIME WILL TELL AS TO WHICH ENERGY DISTRIBUTION WILL BE
CORRECT.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1245 PM CDT SAT SEP 21 2013
SCT-BKN028 TIL 21Z/21 AT KDBQ. ELSEWHERE ONLY SCT030-040 THIS AFTERNOON.
SKC TONIGHT AND SUNDAY AS HIGH PRESSURE BUILDS INTO THE REGION
FROM THE PLAINS. NORTHWEST WINDS 10 TO 15 KNOTS WITH OCNL GUSTS TO
NEAR 20 KNOTS THIS AFTERNOON. VARIABLE WINDS AROUND 5 KNOTS OR
LESS TONIGHT THEN SOUTHEAST WINDS LESS THAN 10 KNOTS SUNDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...DC
SHORT TERM...DC
LONG TERM...ERVIN
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
102 PM EDT SAT SEP 21 2013
.SYNOPSIS...
A SOUTHERLY FLOW WILL BRING WARMER AND INCREASINGLY MOIST AIR TO
THE REGION TODAY. A STRONG COLD FRONT WILL APPROACH THE STATE TONIGHT
AND IS EXPECTED TO MOVE THROUGH THE FORECAST AREA ON SUNDAY.&&
.NEAR TERM /THROUGH TONIGHT/...
1 PM UPDATE: MADE SOME MINOR CHANGES TO TEMPERATURE, WIND, SKY
GRIDS FOR THIS AFTERNOON BASED ON CURRENT CONDITIONS. ALSO MADE
SOME CHANGES TO POP, QPF GRIDS FOR LATER TONIGHT BASED ON THE
LATEST TRENDS WITH RADAR, SATELLITE AND FORECAST GUIDANCE. MAIN
CHANGE WAS TO BEEF UP QPF FOR THE OVERNIGHT PERIOD ALONG THE
WESTERN BORDER OF THE CWA.
PREVIOUS DISCUSSION... CHALLENGE THIS TERM WILL BE
CLOUDS AND DRIZZLE TODAY AND TIMING OF RAIN AND INCREASING WINDS
TONIGHT.
LATEST IR SATL 11.3-3.9 MICRON IMAGERY SHOWING LOW CLOUDS OVER THE
EASTERN 1/2 OF THE CWA THANKS IN PART TO THE SE FLOW. LOW CLOUDS
EXTEND FROM KFVE ALL THE DOWN TO THE KBHB REGION. FURTHER W, HIGH
CLOUDS MOVING ACROSS THE REGION. SOME DRIZZLE OCCURRING MAINLY
ACROSS THE E AND NE SECTIONS PER THE METARS AND WEBCAMS. THE NAM12
AND HRRR HANDLING THE CLOUDS WELL PER THE 06Z ANALYSIS. LATEST
RADAR TRENDS SHOWED DRIZZLE BECOMING MORE SPOTTY AS THE WINDS
BEGIN TO SHIFT TO A MORE S DIRECTION AND THIS PICKED UP WELL BY
THE 00Z NAM AS WELL. ACROSS THE DOWNEAST AND COAST, AREAS OF DRIZZLE
AND FOG THIS MORNING. CONDITIONS ARE EXPECTED TO IMPROVE LATER
THIS MORNING AS THE FLOW BECOMES MORE SLY AND LLVLS DRY OUT.
SUNSHINE RETURNING LATER ON WILL ALLOW FOR TEMPERATURES TO WARM
INTO THE 70S AWAY FROM THE DOWNEAST AND COAST AS S WIND WILL KEEP
TEMPERATURES DOWN ACROSS THE DOWNEAST AND COAST. THE LATEST NAM/RUC
SOUNDINGS POINT TO THIS TAKING PLACE. S WINDS PICKING UP TODAY AT
15 TO 20 MPH WITH HIGHER GUSTS AS SHOWN BY THE 00Z NAM AND 04Z HRRR.
THE TREND CONTINUES TO BE THAT RAIN WILL BE HELD OFF UNTIL LATER
TONIGHT AS A STRONG COLD FRONT BEGINS TO APCH FROM THE W. THE 00Z
RUNS OF THE NAM AND GFS SHOW AN INITIAL BATCH OF SHOWERS/RAIN OUT
AHEAD OF THE FRONT ACROSS THE W AND SW AREAS AND IN RESPONSE TO
AN UPPER LEVEL DISTURBANCE MOVING ACROSS THIS REGION. BUFKIT
PROFILES ALSO SHOW THE POTENTIAL FOR DRIZZLE TO SET UP AGAIN LATER
TONIGHT W/THE INCREASINGLY MOIST S FLOW. SOUNDINGS SHOW LLVLS
BELOW 900MBS MOISTENING W/DRY AIR ABOVE THIS LEVEL INDICATIVE OF
THE POTENTIAL FOR DRIZZLE. ADDED PERIODS OF DRIZZLE STARTING LATER
THIS EVENING AND THEN TRANSITIONING TO RAIN MOVES IN BY SUNDAY
MORNING. THE STEADIEST RAINFALL WILL BE W OF A CARIBOU-BANGOR
LINE. S WINDS WILL BE ON THE INCREASE AS WELL AS SHOWN BY THE
LATEST NAM AND GFS. KEPT WINDS 10 TO 20 MPH TONIGHT W/GUSTS TO 25
MPH.
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A COLD FRONT WILL CROSS THE REGION DURING SUNDAY. THE FRONT WILL
BE ACCOMPANIED BY A PERIOD OF STEADIER RAIN LATER SUNDAY MORNING
AND SUNDAY AFTERNOON. RAINFALL AMOUNTS DURING SUNDAY ARE EXPECTED
TO RANGE FROM THREE-QUARTERS TO ONE INCH AS A LOW LEVEL JET IN THE
925-850 MB LEVEL TRAVERSES THE REGION IN ADVANCE OF THE FRONT. THE
LOW LEVEL JET WILL ALSO RESULT IN GUSTY SOUTH WINDS IN ADVANCE OF
THE FRONT. HAVE INCLUDED THE MENTION OF ISOLATED THUNDER WITH SOME
ELEVATED INSTABILITY AHEAD OF THE FRONT AND THERE CURRENTLY IS
SOME LIGHTNING SHOWING UP IN ADVANCE OF THE BOUNDARY ATTM. THE
FRONT WILL MOVE EAST OF THE DOWNEAST COAST LATER SUNDAY AFTERNOON
ENDING THE STEADIEST RAINFALL.
EXPECT PARTLY TO MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS SUNDAY
NIGHT AND MONDAY AS AN UPPER LEVEL LOW CROSSES THE REGION WITH
PARTLY CLOUDY SKIES DOWNEAST. MUCH COOLER AIR WILL FLOW IN BEHIND
THE FRONT SUNDAY NIGHT AND MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM
THE LOW TO MID 40S AND HIGHS ON MONDAY WILL RANGE FROM THE LOW TO
MID 50S NORTH AND MID TO UPPER 50S DOWNEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AN UPPER LOW WILL SLOWLY MOVE EAST OF THE MARITIMES THROUGH MID
WEEK. THIS WILL KEEP A MAINLY DRY AND CHILLY WEATHER PATTERN
ACROSS THE REGION THROUGH MID WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: IFR ATTM ACROSS ALL THE TERMINALS W/FOG A NUISANCE AS
VSBYS ARE <1 MILE AT KBGR AND KBHB. CONDITIONS ARE EXPECTED TO
IMPROVE LATER THIS MORNING TO MVFR AND THEN VFR. EXPECTING
CONDITIONS TO DROP BACK TO MVFR LATER IN THE EVENING AND THEN DOWN
TO IFR BY EARLY SUNDAY MORNING.
SHORT TERM:IFR/MVFR CONDITIONS CAN BE EXPECTED ON SUNDAY IN RAIN IN
ADVANCE OF AN APPROACHING COLD FRONT. GENERALLY VFR IS EXPECTED
SUNDAY NIGHT AND BEYOND EXCEPT SOME MVFR CIGS ARE IS POSSIBLE AT
TIMES MAINLY ACROSS NORTHERN AREAS.
&&
.MARINE...
NEAR TERM: FOG WILL LEAD TO NAVIGATIONAL PROBLEMS TODAY AS A SSE
WIND CONTINUES. DECIDED TO HOIST AN SCA FOR LATER TONIGHT INTO
SUNDAY AS WINDS ARE FCST TO INCREASE TO SUSTAINED SPEEDS OF 15 TO
20 KTS AND GUSTS TO 25 KTS. LATEST WNAWAVE COMING IN LINE ATTM PER
THE LATEST OBS SHOWING WAVE HEIGHTS OF 2 FT. DECIDED TO FOLLOW THE
DAY CREW`S LEAD OF INCREASING SEAS TO 4 TO 6 FT BY SUNDAY MORNING.
SHORT TERM: A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AS
WINDS/SEAS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EDT SUNDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...FITZSIMMONS/HEWITT/DUDA
MARINE...FITZSIMMONS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT SEP 21 2013
.SYNOPSIS...
A COLD FRONT MOVES GRADUALLY EAST ACROSS THE REGION TONIGHT AND
EARLY SUNDAY...PUSHING OFFSHORE OF NORTH CAROLINA SUNDAY AFTERNOON.
HIGH PRESSURE BUILDS OVER THE REGION BEHIND THE FRONT...REMAINING IN
PLACE AT LEAST THROUGH THE EARLY PART OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED A COLD FRONT FROM THE LOWER GREAT
LAKES THROUGH THE OHIO AND TENNESSEE VALLEYS...HEADED TOWARD THE
TN/NC BORDER. 12Z SOUNDINGS TOWARD KGSO AND KRNK...ALONG WITH THE
UPPER-AIR ANALYSIS...SHOWED A LAYER OF GOOD DRYING AROUND 500MB...
COINCIDENT WITH SOME CLEARING OVER THE SOUTHWEST PIEDMONT AND A LACK
OF RETURNS ON NEARBY RADARS TO THE WEST. AS THE SHORTWAVE RIDGE ALSO
OVER THE AREA OF DRYING/CLEARING DAMPENS AND MOVES EAST...DIFFLUENCE
INCREASES FOR THE AFTERNOON. ALREADY...WIDESPREAD SHOWERS WERE NOTED
ON REGIONAL RADARS MOVING INTO THE WESTERN QUARTER OF THE STATE...
MOVING GRADUALLY EAST.
LIFT INCREASES FOR THE AFTERNOON OVER CENTRAL NORTH CAROLINA AS
DIFFLUENCE AHEAD OF THE SURFACE COLD FRONT MOVES EAST. IN THE MOIST
AIR MASS OVER CENTRAL NORTH CAROLINA...WITH PRECIPITABLE WATER
VALUES FROM 1.75 INCHES TO 2 INCHES THIS AFTERNOON...AND AS THE LIFT
INCREASES SCATTERED SHOWERS SHOULD DEVELOP EARLY...FOLLOWED BY MORE
NUMEROUS TO WIDESPREAD SHOWERS SPREADING GRADUALLY FROM WEST TO EAST
OVER THE AREA. THE LATEST RAP SHOWS A MODERATELY-STRONG MID-LEVEL
SHORTWAVE WEAKENING SOME AS IT MOVES EAST AND APPROACHES CENTRAL
NORTH CAROLINA...AND THE RAP 850MB THETA-E DOES NOT RECOVER FROM IN
THAT MODEL/S FORECAST FROM HIGH VALUES EARLIER THIS MORNING. ALSO...
MLCAPE OVER THE AREA BARELY REGISTERS...WITH LOW DCAPE AND LIFTED
INDICES ONLY FALLING TO AROUND 0C. GIVEN THE CURRENT UPPER-AIR AND
AIRCRAFT SOUNDINGS...ALONG WITH THE RAP FORECAST SOUNDINGS THROUGH
00Z...ALL SHOWING SOME WARMING ALOFT AROUND 500MB WHICH DOES NOT
SEEM TO CHANGE GIVEN UPSTREAM TEMPERATURES...THUNDER SHOULD BE HARD
TO COME BY AT LEAST INTO THE EARLY EVENING. TEMPERATURE PROFILES ON
RAP MODEL SOUNDINGS THROUGH 00Z ARE ALL AVERAGING AT OR RIGHT OF THE
MOIST ADIABAT. PRECIPITATION INTENSITY COULD WANE OVER OUR AREA
COMPARED TO RADAR RETURNS UPSTREAM...BUT THERE SHOULD BE ENOUGH
COVERAGE FOR NUMEROUS TO WIDESPREAD SHOWERS...AND POSSIBLY AN
ISOLATED RUMBLE OF THUNDER...FROM THE LATE AFTERNOON INTO THE
EVENING HOURS. CURRENT TEMPERATURE FORECAST IS LIKELY AT OR JUST
BEYOND THE HIGH END OF THE EXPECTED RANGE AND WILL WATCH THE
PROGRESSION OF FLEETING CLEARING ON VISIBLE IMAGERY...LIKELY NEEDING
TO MODIFY LOWER MAXES IN AREAS IN A SUBSEQUENT LATE-MORNING UPDATE.
TONIGHT...WHILE NEARLY THE ENTIRE FORECAST AREA SHOULD SEE
MEASURABLE RAIN...THE SPECIFICS OF ENDING TIMING AND AMOUNTS ARE
LESS CERTAIN. WILL STICK CLOSER TO THE NAM/GFS/WRF-ARW/WRK-NMM/SREF
MEAN TIMING...SHOWING THE HIGH POPS TAPERING DOWN LATE TONIGHT FROM
NW TO SE...BUT WILL SLOW THE EXIT DOWN BY A COUPLE OF HOURS AS A NOD
TO THE CONSISTENT ECMWF. AND...WHILE WE COULD SEE A FEW TRAINING
SHOWERS CAUSING LOCALLY HIGHER RAIN TOTALS...WILL HOLD AMOUNTS DOWN
GIVEN THIS VERY REAL POSSIBILITY OF A "CAROLINA SPLIT" IN THE PRECIP
SHIELD...AS THE BETTER DYNAMIC FORCING FOR ASCENT (INCLUDING UPPER
DIVERGENCE WITH THE POLAR STREAM JET) COULD HEAD TO OUR NORTH...
WHILE THE BETTER THERMODYNAMICS AND LOW LEVEL MASS CONVERGENCE MAY
HOLD JUST TO OUR SOUTH. LOWS 60-66 ARE IN LINE WITH STATISTICAL
GUIDANCE.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 255 AM SATURDAY...
WITH THE ABOVE REASONING IN MIND... WILL HOLD ONTO A CHANCE OF RAIN
IN THE EAST THROUGH SUNDAY MORNING. FORECAST SOUNDINGS DEPICT LOTS
OF DRY AND RATHER STABLE MID-UPPER LEVEL AIR PUSHING IN FROM THE WNW
BEHIND THE MID LEVEL TROUGH AXIS. BUT LOW LEVEL FLOW IS EXPECTED TO
BECOMING EASTERLY OR ENE BEHIND THE FRONT AS IT TAKES ON A MORE
NW-SE ORIENTATION... GIVEN THE RAPID LOOSENING OF THE HEIGHT
GRADIENT ALOFT AS THE SOUTHERN PORTION OF THE TROUGH WEAKENS. THIS
SHOULD SERVE TO HOLD CLOUDS IN LONGER ACROSS THE SRN AND ERN CWA
THROUGH MUCH OF SUNDAY... WITH LINGERING LIGHT RAIN POSSIBLE IN THE
FAR SOUTHEAST WELL INTO THE DAY. AGAIN... CONFIDENCE IN THIS
SCENARIO IS NOT TERRIBLY HIGH. WILL HOLD ONTO RAIN CHANCES MAINLY IN
THE SOUTHEAST A LITTLE LONGER INTO THE DAY. COLD AIR ADVECTION WILL
NOT BEGIN IN EARNEST UNTIL LATE IN THE DAY... ALTHOUGH THE EASTERLY
FLOW MAY ALLOW FOR LITTLE HEATING IN THE SE SECTIONS WITH TEMPS
POTENTIALLY HOLDING IN THE 70S AREAWIDE. HAVE TRIMMED A DEGREE OR
TWO OFF HIGHS... TO RANGE FROM 76 TO 80. EXPECT SCATTERED CLOUDS TO
HOLD ON OVERNIGHT ESPECIALLY IN CENTRAL/ERN PARTS OF THE FORECAST
AREA GIVEN EXPECTED MOISTURE TRAPPED BENEATH THE SUBSIDENCE
INVERSION ALOFT WITH LITTLE OPPORTUNITY FOR DISPERSION VERTICALLY OR
HORIZONTALLY. LOWS AROUND 50 NORTH TO NEAR 59 SOUTH. -GIH
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...
AN AMPLIFIED...BUT RELATIVELY PROGRESSIVE UPPER LEVEL FLOW WILL LEAD
TO RIDGING OVER THE EASTERN US WHILE A SHORTWAVE MOVING ONSHORE OF
THE WEST COAST TODAY TRACKS ACROSS THE CENTRAL US MONDAY AND
TUESDAY. AT THE SURFACE...HIGH PRESSURE WILL SETTLE OVER EASTERN
CANADA AND EXTEND DOWN THE EAST COAST. THE MAIN FORECAST CHALLENGE
IS THE AFOREMENTIONED SHORTWAVE...WITH MEDIUM RANGE MODEL GUIDANCE
SHOWING SIGNIFICANTLY DIFFERENT IMPACTS. THE ECMWF PUSHES THE
SHORTWAVE THROUGH THE RIDGE...DRAWING MORE MOISTURE NORTH FROM THE
GULF OF MEXICO ATOP THE SURFACE RIDGE...LEADING TO MORE CLOUD
COVER/PRECIP...AND EVENTUALLY CYCLOGENESIS ALONG THE STALLED FRONTAL
ZONE OFF THE SOUTHEAST COAST. THE GFS LIFTS THE SHORTWAVE
TOWARD THE GREAT LAKES AND LEAVES THE SOUTHEAST US DRY. WPC PREFERS
AN ECMWF-LIKE SOLUTION BASED AN ENSEMBLE GUIDANCE...WHICH WOULD
STILL KEEP MOST PRECIP SOUTH OF THE CWA AND LIMIT A COLD AIR DAMMING
SCENARIO. WILL INDICATE A CHANCE POP ACROSS SOUTHERN COUNTIES ON
WEDNESDAY...WITH JUST A SLIGHT CHANCE TO THE NORTH. HIGHS WILL
GENERALLY BE AT OR BELOW NORMAL FOR MOST OF THE WEEK...COOLEST
TUESDAY/WEDNESDAY WITH ADDED CLOUD COVER...AND SHOULD RISE BACK TO
AROUND OR JUST ABOVE NORMAL BY THE END OF THE WEEK AHEAD OF THE NEXT
COLD FRONT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 155 PM SATURDAY...
AREAS OF MVFR CEILINGS HAVE HELD FIRM INTO EARLY AFTERNOON
ESPECIALLY OVER THE WESTERN PIEDMONT. WHILE THERE SHOULD BE SOME
LIFTING OF THE CEILINGS EVEN THERE FOR A PERIOD...SCATTERED SHOWERS
AND AREAS OF RAIN...WITH INCREASING MOISTURE...WILL SPREAD EAST AND
RESULT IN A RETURN TO SUB-VFR CONDITIONS THIS EVENING. OVERNIGHT...
GUIDANCE IS CONSISTENT WITH NUMEROUS TO WIDESPREAD AREAS OF IFR
CONDITIONS DUE TO CEILINGS ACROSS CENTRAL NORTH CAROLINA...AS AREAS
OF SHOWERS GRADUALLY MOVE EAST. IFR CONDITIONS CONTINUE INTO EARLY
SUNDAY BEFORE CONDITIONS INCREASE TO MVFR DURING THE MORNING...
POSSIBLY TO VFR BY SUNDAY AFTERNOON. BEYOND THE 18Z VALID TAF
PERIOD...SOME MVFR CEILINGS COULD CONTINUE INTO THE AFTERNOON SUNDAY
MAINLY TOWARD KFAY AND KRWI. BY SUNDAY NIGHT...WIDESPREAD VFR
CONDITIONS ARE EXPECTED...AND THESE CONDITIONS SHOULD LARGELY
PERSIST THROUGH THE MIDDLE OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...DJF