Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/24/14
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
550 AM MST FRI AUG 22 2014
.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.
&&
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE AREA TODAY...HOWEVER
ONLY A FEW ISOLATED SHOWERS ARE EXPECTED ACROSS THE REGION. DRIER
CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND ALONG
WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES. A RETURN TO A MORE
TYPICAL MONSOON PATTERN IS EXPECTED NEXT WEEK...WITH AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE WAS SITUATED OVER NORTH-CENTRAL ARIZONA
THIS MORNING AS OF 0830Z...WITH THE MAJORITY OF THE STORM ACTIVITY
WELL AHEAD OF THE LOW IN NEW MEXICO. WHILE THERE WERE A FEW SHOWERS
NOTED ON RADAR BENEATH THE UPPER LEVEL DEFORMATION ZONE /LOCATED
APPROXIMATELY ALONG INTERSTATE 17/...THE STORMS FROM THURSDAY
EVENING HAD LARGELY DISSIPATED ACROSS THE DESERTS. IN THE WAKE OF
THIS STORM...TEMPERATURES WERE GENERALLY IN THE UPPER 60S TO LOWER
70S ACROSS THE DESERTS...APPROXIMATELY 10 DEGREES BELOW NORMAL FOR
MID/LATE AUGUST.
STRONG ISENTROPIC DESCENT IS EXPECTED ACROSS THE REGION TODAY AS THE
TROUGH MOVES OUT OF THE AREA. BL MOISTURE WILL REMAIN SOMEWHAT
ELEVATED AS 1000-700MB MEAN MIXING RATIOS WILL STILL LINGER IN THE
8-12 G/KG RANGE...HOWEVER THE LACK OF UPPER LEVEL SUPPORT SHOULD
PRECLUDE MUCH IN THE WAY OF WIDESPREAD SHOWERS AND THUNDERSTORMS.
GIVEN THE CLOSER PROXIMITY TO THE DEPARTING LOW...I WOULD EXPECT TO
SEE A FEW POP-UP SHOWERS NORTH AND EAST OF PHOENIX WITH LITTLE OF
CONSEQUENCE ACROSS THE DESERTS. THERE COULD ALSO BE SOME ACTIVITY
ACROSS PORTIONS OF SOUTHEAST ARIZONA THAT GLANCES PINAL COUNTY...BUT
THAT WOULD BE ABOUT IT. HI-RES WRF MODELS ALONG WITH THE HRRR PAINT
A SIMILAR SOLUTION FOR TODAY. MORE SUBSTANTIAL BL DRYING IS EXPECTED
THIS WEEKEND AS ALL OPERATIONAL MODELS SUGGEST MIXING RATIOS WILL
DROP TO AROUND 3-4 G/KG ACROSS SOUTHEAST CALIFORNIA AND TO 6-8 G/KG
ACROSS ARIZONA. WITH EVEN LESS UPPER LEVEL SUPPORT THIS
WEEKEND...POPS WILL REMAIN SUBSTANTIALLY BELOW CLIMO THIS WEEKEND.
NEXT WEEK WILL SEE A RETURN TO A MORE TYPICAL MONSOON SETUP AS HIGH
PRESSURE SLIDES EAST AND LOW LEVEL WINDS TURN AROUND OUT OF THE
SOUTHEAST. WHILE THERE ARE SOME DIFFERENCES IN THE MODELS REGARDING
A TROUGH MOVING THROUGH UTAH BY THE MIDDLE OF NEXT WEEK...BOTH THE
GFS AND EUROPEAN...AS WELL AS THE 12Z NAEFS INDICATE A NOTEWORTHY
INCREASE IN MOISTURE ACROSS THE AREA MONDAY/TUESDAY NEXT WEEK. THIS
COULD BE THE RESULT OF THE PASSAGE OF A TROPICAL SYSTEM WELL SOUTH
OF THE GULF OF CALIFORNIA...OR IT COULD SIMPLY BE OUTFLOW DRIVEN
FROM CONVECTION OVER SONORA. REGARDLESS...MIXING RATIOS EXPECTED TO
RETURN TO THE 10-12 G/KG RANGE EARLY NEXT WEEK WHICH SHOULD SET THE
STAGE FOR AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY THROUGH AT
LEAST FRIDAY. TOUGH TO PICK OUT ONE ACTIVE DAY OVER ANOTHER...BUT
POPS HAVE BEEN NUDGED TOWARD CLIMO /AND SLIGHTLY HIGHER EAST OF
PHOENIX/ FROM TUESDAY THROUGH FRIDAY.
AS FOR TEMPERATURES...THE BOUNDARY LAYER WILL STRUGGLE TO RECOVER
TODAY AND TEMPERATURES SHOULD REMAIN BELOW NORMAL. SOME RECOVERY IS
EXPECTED ON SATURDAY WITH A RETURN TO NORMAL TEMPERATURES EXPECTED
SUNDAY THROUGH THE END OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA
INCLUDING KPHX...KIWA...KSDL...KIPL..AND KBLH...
A WEAKENING UPPER LOW WAS CENTERED JUST WEST OF PHX AT 12Z AND WILL
CONTINUE SHIFTING EAST DURING THE DAY WITH FURTHER WEAKENING.
ANTICIPATE FEW-SCT BASES AT 8-10 KFT MSL...BECOMING SCT-BKN BY
MIDDAY OVER HIGHER TERRAIN NEAR AND EAST OF PHOENIX METRO. A STRAY
SHOWER CANNOT BE RULED OUT OVER SOUTH-CENTRAL ARIZONA INCLUDING
PHOENIX AREA...MORE LIKELY FURTHER EAST...BUT PROBABILITY TOO LOW TO
REFLECT IN TAFS. EXPECT CLEAR SKIES THIS EVENING AS THE SYSTEM
SHIFTS INTO NEW MEXICO AND WEAKENS EVEN FURTHER. SURFACE WINDS OVER
PHOENIX AREA WILL FAVOR EAST AND SOUTHEAST DIRECTIONS THIS MORNING
BEFORE TRANSITIONING TO WESTERLY AROUND MIDDAY. SURFACE WINDS OVER
SOUTHWEST AZ AND SOUTHEAST CA WILL HOLD ON TO SOUTHERLY COMPONENT
LONGER BEFORE TRENDING TOWARD SOUTHWEST AND WEST THIS
EVENING...LOCAL GUSTS TO 20 KTS THIS EVENING IMPERIAL VALLEY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
HUMIDITIES WILL TREND UPWARD MONDAY AND TUESDAY BEFORE STARTING TO
TREND DOWNWARD THURSDAY. OVERNIGHT RECOVERY WILL REMAIN GOOD THROUGH
THE WEEK. STORM CHANCES WILL REMAIN SLIGHT AND FAVOR THE HIGHER
TERRAIN OF SOUTH-CENTRAL ARIZONA HOWEVER THEY WILL EXPAND SLOWLY
WESTWARD TO NEAR THE LOWER COLORADO RIVER VALLEY BY WEDNESDAY.
HAINES INDEX VALUES PEAK AT 5 OVER PORTIONS OF SOUTHEAST CALIFORNIA
AND SOUTHWEST ARIZONA SUNDAY AND MONDAY BEFORE TRENDING DOWNWARD.
EXPECT LOWER VALUES OVER SOUTH-CENTRAL ARIZONA DUE TO BETTER
ATMOSPHERIC MOISTURE CONTENT.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
157 AM MST FRI AUG 22 2014
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE AREA TODAY...HOWEVER
ONLY A FEW ISOLATED SHOWERS ARE EXPECTED ACROSS THE REGION. DRIER
CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND ALONG
WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES. A RETURN TO A MORE
TYPICAL MONSOON PATTERN IS EXPECTED NEXT WEEK...WITH AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE WAS SITUATED OVER NORTH-CENTRAL ARIZONA
THIS MORNING AS OF 0830Z...WITH THE MAJORITY OF THE STORM ACTIVITY
WELL AHEAD OF THE LOW IN NEW MEXICO. WHILE THERE WERE A FEW SHOWERS
NOTED ON RADAR BENEATH THE UPPER LEVEL DEFORMATION ZONE /LOCATED
APPROXIMATELY ALONG INTERSTATE 17/...THE STORMS FROM THURSDAY
EVENING HAD LARGELY DISSIPATED ACROSS THE DESERTS. IN THE WAKE OF
THIS STORM...TEMPERATURES WERE GENERALLY IN THE UPPER 60S TO LOWER
70S ACROSS THE DESERTS...APPROXIMATELY 10 DEGREES BELOW NORMAL FOR
MID/LATE AUGUST.
STRONG ISENTROPIC DESCENT IS EXPECTED ACROSS THE REGION TODAY AS THE
TROUGH MOVES OUT OF THE AREA. BL MOISTURE WILL REMAIN SOMEWHAT
ELEVATED AS 1000-700MB MEAN MIXING RATIOS WILL STILL LINGER IN THE
8-12 G/KG RANGE...HOWEVER THE LACK OF UPPER LEVEL SUPPORT SHOULD
PRECLUDE MUCH IN THE WAY OF WIDESPREAD SHOWERS AND THUNDERSTORMS.
GIVEN THE CLOSER PROXIMITY TO THE DEPARTING LOW...I WOULD EXPECT TO
SEE A FEW POP-UP SHOWERS NORTH AND EAST OF PHOENIX WITH LITTLE OF
CONSEQUENCE ACROSS THE DESERTS. THERE COULD ALSO BE SOME ACTIVITY
ACROSS PORTIONS OF SOUTHEAST ARIZONA THAT GLANCES PINAL COUNTY...BUT
THAT WOULD BE ABOUT IT. HI-RES WRF MODELS ALONG WITH THE HRRR PAINT
A SIMILAR SOLUTION FOR TODAY. MORE SUBSTANTIAL BL DRYING IS EXPECTED
THIS WEEKEND AS ALL OPERATIONAL MODELS SUGGEST MIXING RATIOS WILL
DROP TO AROUND 3-4 G/KG ACROSS SOUTHEAST CALIFORNIA AND TO 6-8 G/KG
ACROSS ARIZONA. WITH EVEN LESS UPPER LEVEL SUPPORT THIS
WEEKEND...POPS WILL REMAIN SUBSTANTIALLY BELOW CLIMO THIS WEEKEND.
NEXT WEEK WILL SEE A RETURN TO A MORE TYPICAL MONSOON SETUP AS HIGH
PRESSURE SLIDES EAST AND LOW LEVEL WINDS TURN AROUND OUT OF THE
SOUTHEAST. WHILE THERE ARE SOME DIFFERENCES IN THE MODELS REGARDING
A TROUGH MOVING THROUGH UTAH BY THE MIDDLE OF NEXT WEEK...BOTH THE
GFS AND EUROPEAN...AS WELL AS THE 12Z NAEFS INDICATE A NOTEWORTHY
INCREASE IN MOISTURE ACROSS THE AREA MONDAY/TUESDAY NEXT WEEK. THIS
COULD BE THE RESULT OF THE PASSAGE OF A TROPICAL SYSTEM WELL SOUTH
OF THE GULF OF CALIFORNIA...OR IT COULD SIMPLY BE OUTFLOW DRIVEN
FROM CONVECTION OVER SONORA. REGARDLESS...MIXING RATIOS EXPECTED TO
RETURN TO THE 10-12 G/KG RANGE EARLY NEXT WEEK WHICH SHOULD SET THE
STAGE FOR AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY THROUGH AT
LEAST FRIDAY. TOUGH TO PICK OUT ONE ACTIVE DAY OVER ANOTHER...BUT
POPS HAVE BEEN NUDGED TOWARD CLIMO /AND SLIGHTLY HIGHER EAST OF
PHOENIX/ FROM TUESDAY THROUGH FRIDAY.
AS FOR TEMPERATURES...THE BOUNDARY LAYER WILL STRUGGLE TO RECOVER
TODAY AND TEMPERATURES SHOULD REMAIN BELOW NORMAL. SOME RECOVERY IS
EXPECTED ON SATURDAY WITH A RETURN TO NORMAL TEMPERATURES EXPECTED
SUNDAY THROUGH THE END OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
AN AREA OF SHOWERS AND A FEW LINGERING EMBEDDED THUNDERSTORMS WILL
AFFECT THE PHOENIX TERMINALS THROUGH AROUND 06Z BEFORE GRADUALLY
DIMINISHING AND LIFTING OUT OF THE AREA TO THE NORTHEAST. GUSTY
OUTFLOW WINDS GENERALLY OUT OF THE SOUTHWEST WILL LAST INTO LATE
EVENING...BUT DIMINISH CONSIDERABLY BY MIDNIGHT. NOW EXPECTING A
DELAYED ONSET TO DOWNSLOPE EASTERLY WINDS...LIKELY NOT SWITCHING
AROUND UNTIL 09-10Z. CIGS AT 10-12K FEET WILL LINGER THROUGH MUCH OF
THE OVERNIGHT...BEFORE SCATTERING OUT AROUND DAYBREAK. AN ISOLATED
SHOWER AND THUNDERSTORM THREAT WILL AGAIN BE POSSIBLE FOR FRIDAY
AFTERNOON...BUT CONFIDENCE IN AFFECTING AREA TERMINALS IS FAIRLY LOW
AT THIS POINT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THE UPPER LOW CENTER HAS PUSHED INTO SOUTHWEST ARIZONA WITH CLOUDS
BEGINNING TO SCATTER OUT FROM WEST TO EAST ACROSS SOUTHEAST
CALIFORNIA. A GENERAL WESTERLY WIND COMPONENT IS EXPECTED THROUGH
THE OVERNIGHT. SKIES WILL LIKELY CLEAR OUT SOMETIME FRIDAY MORNING
WITH ONLY SOME LINGERING HIGH CIRRUS POSSIBLE FOR THE REST OF FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
QUIET WEATHER IS EXPECTED ON SUNDAY...HOWEVER HUMIDITIES WILL
INCREASE AS WE GET INTO NEXT WEEK WITH A BIG JUMP EXPECTED ON MONDAY
INTO TUESDAY. CONSEQUENTLY...THE CHANCES OF AFTERNOON SHOWERS AND
THUNDERSTORMS WILL STEADILY INCREASE THROUGH THE WEEK. THE GREATEST
STORM CHANCES WILL BE IN THE USUAL LOCATIONS NORTH AND EAST OF
PHOENIX...WITH LESSER CHANCES ACROSS THE DESERTS. AS FOR
HUMIDITIES...OVERNIGHT RECOVERIES WILL BE GOOD THROUGH NEXT WEEK
WITH NO MAJOR WIDESPREAD WIND EVENTS EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1151 AM MDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 1135 AM MDT FRI AUG 22 2014
CONVECTION CONTINUES IN AREA OF ISENTROPIC LIFT OVER NORTHEASTERN
COLORADO. THIS HAD BEEN GRADUALLY LIFTING NORTH...THOUGH WITH
HEATING IT HAS BEGUN TO FILL BACK IN TOWARD THE SOUTH. WE WILL
NEED TO WATCH THE AREA BETWEEN STERLING AND AKRON AS THIS AREA
RECEIVED RAIN EARLIER THIS MORNING. FORTUNATELY THAT IS NOT A
FLOOD PRONE AREA. MEANWHILE LARGE AREA OF LIFT IS PROGRESSING
NORTHEAST FROM THE SOUTHERN AND CENTRAL MOUNTAINS AND HAS FILLED
IN PRETTY WELL WITH RAIN SHOWERS. EXPECT THE MAIN STORY TODAY WILL
BE THIS AREA OF FAIRLY STEADY RAIN MOVING NORTHEAST.
BIG QUESTION IS THE OUTLOOK FOR STRONGER THUNDERSTORMS...AND THE
ANSWER REMAINS MUDDLED BUT ORGANIZED STRONG CONVECTION IS LOOKING
LESS LIKELY. FRONTAL ZONE IS RATHER DIFFUSE...THOUGH THERE IS A
BROAD AREA OF CONVERGENCE FROM THE CURRENT NE COLORADO CONVECTION
SOUTH TOWARD THE ARKANSAS RIVER. LIFT FROM THE UPSTREAM SHORTWAVE
IS CREATING PRESSURE FALLS OVER NE COLORADO...HOLDING THIS
CONVERGENCE AREA IN PLACE BUT NOT REALLY FOCUSING IT ANY MORE.
LARGER SCALE MODELS HAVE A BETTER DEFINED FRONTAL ZONE AND BLOW UP
CONVECTION ON IT...WITH HEAVY RAIN ON THE NORTH SIDE AND A
POTENTIAL SUPERCELLS NORTH OF THE WARM FRONT SCENARIO WITH STRONG
EASTERLY WINDS. MEANWHILE THE HRRR DEVELOPS STORMS ON THE LEADING
EDGE OF THE MOUNTAIN RAIN AREA AND THEY MOVE QUICKLY TOWARD THE
NORTHEAST...WHILE THE FRONTAL ZONE CONVECTION IS LIMITED TO
KANSAS. I DO THINK THE TIGHT FRONTAL ZONE IS WRONG ALONG WITH THE
SIGNIFICANT PLUME OF MOISTURE ON LOW LEVEL EASTERLY WINDS...THAT
JUST IS NOT HAPPENING. THUS I HAVE PARED BACK THE SEVERE THREAT TO
OUR EASTERNMOST AREAS...AND IT IS PROBABLY JUST THE EASTERN PARTS
OF LINCOLN AND WASHINGTON COUNTIES AND AREAS EAST OF THERE. AREAS
FURTHER WEST AND NORTH WILL STILL HAVE A HEAVY RAIN THREAT IF
THERE IS REGENERATION ON AN EAST-WEST ZONE...AND OBVIOUSLY SOME
POTENTIAL FOR THAT TO CONTINUE. PREVIOUS OUTLOOKS OF UP TO 3
INCHES IN 2 HOURS IF THERE IS TRAINING SEEM ALRIGHT...BUT THE
THREAT SHOULD BE LIMITED TO THOSE EASTERN PLAINS AREAS AS
CONVECTION FURTHER WEST SHOULD BE QUITE A BIT WEAKER WITH FAST
CELL MOTIONS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 318 AM MDT FRI AUG 22 2014
AN UPPER LEVEL LOW OVER CENTRAL ARIZONA WILL GRADUALLY MOVE NE
INTO THE FOUR CORNERS BY MIDDAY AND THEN INTO NE COLORADO BY EARLY
THIS EVENING. AS THIS FEATURE MOVES ACROSS A DECENT SHOT OF MID
LVL QG ASCENT WILL OCCUR AS WELL. AT THE SFC LOW PRES WILL EXTEND
FM SC WY INTO SERN CO WITH A WK SFC HIGH OVER WRN NEBRASKA. THIS
WILL ALLOW FOR ESE LOW LVL FLOW TO DVLP BY MIDDAY OVER NERN CO AND
ALLOW FOR DEEPER LOW LVL MOISTURE TO ADVECT INTO THE PLAINS.
OVERALL SHOULD SEE A GOOD CHC OF SHOWERS AND TSTMS ACROSS MUCH OF
THE AREA STARTING IN THE MTNS BY MIDDAY AND THEN SPREADING ACROSS
THE PLAINS BY EARLY EVENING.
PRECIPITABLE WATER VALUES ARE FCST TO BE AROUND AN INCH IN THE
MTNS WITH 1.25 TO 1.5 INCHES OVER THE PLAINS SO THE STORMS WILL
PRODUCE HEAVY RAIN...HOWEVER THEY WILL BE QUICK MOVING DUE TO
RATHER STG MID LVL FLOW. THERE WILL BE SOME POTENTIAL FOR TRAINING
OF CELLS OVER THE PLAINS SO COULD SEE A FEW SPOTS RECEIVE FM 2 TO
3 INCHES OF RAIN. AS FOR SVR POTENTIAL MAIN THREAT WOULD BE STRONG
WINDS DUE TO WET MICROBURSTS. ALSO CAN NOT RULE OUT A FEW
TORNADOES AS WELL AS STORM RELATIVE HELICITIES INCREASE BY LATE
AFTN INTO THE EARLY EVENING HOURS OVER THE PLAINS. AS FOR HIGHS
THIS AFTN WILL KEEP READINGS IN THE UPPER 70S TO MID 80S OVER THE
PLAINS.
BY TONIGHT AS MAIN DISTURBANCE MOVES QUICKLY NE SHOULD SEE PRECIP
CHANCES DECREASE ALONG THE FRONT RANGE BY EARLY EVENING AND THEN
BY MIDNIGHT OVER THE FAR NERN PLAINS. SOME MOISTURE MAY LINGER IN
THE NRN MTNS OVERNIGHT SO WILL KEEP IN A CHC OF SHOWERS MAINLY
NORTH OF I-70.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM MDT FRI AUG 22 2014
A DRIER SOUTHWESTERLY FLOW ALOFT WILL BE OVER NERN CO EARLY
SATURDAY FOLLOWING THE PASSAGE OF THE UPPER LEVEL TROUGH. THIS
WILL BE SHORT LIVED...AS ANOTHER SYSTEM OVER SRN IDAHO AT 12Z
SATURDAY MAKES ITS WAY ACROSS MONTANA/WYOMING LATE SATURDAY
AFTERNOON AND SATURDAY NIGHT. THE FLOW ALOFT OVER COLORADO WILL
INCREASE FM THE WEST WITH SCATTERED SHOWERS AND THUNDERSTORMS IN
THE MOUNTAINS. ALONG THE FRONT RANGE FOOTHILLS...URBAN CORRIDOR
AND ADJACENT PLAINS WILL MINIMIZE THE POPS SOUTH AND EAST OF
DENVER WITH HIGHER POPS TO THE NORTH AND WEST....AS THE TROF AXIS
BRUSHES ACROSS THE STATE. SUNDAY AND SUNDAY NIGHT...A DRIER
WESTERLY FLOW ALOFT WILL BE OVER THE CWA. IT WILL BE STABLE AND
COOLER FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY NIGHT INTO
SUNDAY MORNING. THE NAM12/ECMWF GENERATE LITTLE QPF OVER THE
REGION ON SUNDAY WHILE THE GFS DOES REFLECTS MORE SUBTROPICAL
MOISTURE EMBEDDED IN THE FLOW. WL LEAN TOWARD THE NAM12/ECMWF
SOLUTIONS WITH MINIMAL POPS MAINLY OVER THE MOUNTAINS IN THE
AFTN/EVNG. SUNDAY NIGHT INTO MONDAY...THE FLOW ALOFT BECOMES MORE
SOUTHWESTERLY WHICH MAY HELP TAP INTO THE SUBTROPICAL MOISTURE
OVER ERN AZ/NEW MX. POPS STILL ON THE LOW SIDE MONDAY
AFTERNOON/EVENING. THE NEXT SYSTEM IS PROGGED TO DROP OUT OF THE
NORTHERN ROCKIES AND ACROSS COLORADO TUESDAY AND TUESDAY NIGHT.
THE TROUGH AXIS AND ITS ASSOCIATED COLD FRONT WILL PASS ACROSS
NORTHERN COLORADO ON TUESDAY. IT WILL BE COOLER WITH A BETTER
CHANCE OF SHOWERS AND TSTMS AT THAT TIME. WEDNESDAY INTO
THURSDAY...AN UPPER RIDGE DEVELOPS OVER THE WESTERN U.S. WITH A
DRIER NORTHWESTERLY FLOW ALOFT OVER COLORADO. AS A RESULT...LESS
POPS WITH MODERATING TEMPERATURES FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 1135 AM MDT FRI AUG 22 2014
SHOWERS WILL BE FAIRLY WIDESPREAD AROUND THE DENVER AREA THROUGH
THIS EVENING...WITH EMBEDDED THUNDERSTORMS. THE THREAT OF VERY
HEAVY RAIN WITH IFR CONDITIONS IS NOW LOOKING LOW...BUT THERE
SHOULD BE ENOUGH RAIN TO LOWER CEILINGS/VISIBILITIES WITH AREAS
OF MVFR IN THE LATE AFTERNOON AND EVENING. IT APPEARS THAT
CLEARING WILL BE SLOWER ON SATURDAY MORNING...BUT THERE IS STILL A
LOW CHANCE OF IFR/LIFR FOG FOR A FEW HOURS IF IT DOES CLEAR OUT
EARLY ENOUGH. FOR THE REST OF SATURDAY VFR CONDITIONS ARE EXPECTED
WITH ONLY ISOLATED LATE AFTERNOON THUNDERSTORMS.
&&
.HYDROLOGY...
ISSUED AT 318 AM MDT FRI AUG 22 2014
STORMS WILL MOVE QUICKLY TODAY HOWEVER THERE WILL BE SOME POTENTIAL
FOR TRAINING OF STORMS OVER NORTHEAST COLORADO AS A FEW LOCATIONS
COULD SEE UP TO 2 INCHES OF RAIN IN LESS THAN HOUR. IN THE
FOOTHILLS AND MTNS ISOLATED AMOUNTS UP TO AN INCH IN LESS THAN AN
HOUR WILL BE POSSIBLE WITH SOME MINOR FLOODING IN THE BURN SCARS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GIMMESTAD
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...GIMMESTAD
HYDROLOGY...RPK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 AM MDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 1054 AM MDT FRI AUG 22 2014
UPDATED TO INCREASE PRECIPITATION CHANCES ACROSS ALL OF SOUTHERN
COLORADO THROUGH THIS AFTERNOON. RAIN HAS STARTED TO BLOSSOM ON
RADAR ACROSS THE REGION LATE THIS MORNING...AND AS THE UPPER
SYSTEM OVER NORTHWEST NEW MEXICO LIFTS ACROSS COLORADO...IT SHOULD
PROVIDE FOCUS FOR RAINFALL AND THUNDERSTORM ENHANCEMENT. STILL
WATCHING THE POTENTIAL FOR HEAVIER RAINFALL OVER PORTIONS OF THE
AREA...FROM FREMONT COUNTY...NORTHEAST OVER TELLER AND EL PASO
COUNTIES FOR THIS AFTERNOON. DEWPOINTS HAVE CLIMBED INTO THE 50S
WITH NORTHEASTERLY UPSLOPE FLOW ARE WORKING IN FAVOR OF THE HEAVY
RAIN POTENTIAL...HOWEVER DENSE CLOUD COVER WILL HELP LIMIT
INSTABILITY AND MAY HELP KEEP RAINFALL RATES DOWN. THE MAIN CAVEAT
WILL BE HOW THE UPPER LEVEL SYSTEM IMPACTS THE LOWER LEVEL
INGREDIENTS. WHILE A FLASH FLOOD WATCH IS NOT IN EFFECT AT THIS
TIME DUE TO THE UNCERTAINTY OF RAINFALL RATES...PEOPLE IN AND
AROUND FLASH FLOOD PRONE AREAS SHOULD BE ON ALERT THROUGH AT LEAST
6 PM THIS EVENING. MOZLEY
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM MDT FRI AUG 22 2014
...POTENT STORM SYSTEM TO WILL BRING FAST MOVING THUNDERSTORMS
CAPABLE OF LOCALLY HEAVY RAINFALL...SMALL HAIL...AND LIGHTNING TO
SOUTH CENTRAL AND SOUTHEAST COLORADO...WITH POTENTIAL FOR SEVERE
WEATHER FOR NORTHERN PORTIONS OF THE SOUTHEAST PLAINS BY AFTERNOON...
UPPER LOW OVER WESTERN AZ IS FORECAST TO EJECT TO THE NORTHEAST
TODAY...AS THE KICKER SYSTEM DROPS THROUGH THE PACIFIC NORTHWEST.
ALREADY HAVE A ROUND OF THUNDERSTORMS ONGOING ACROSS EAST CENTRAL
AND NORTHEAST COLORADO ALONG/NORTH OF THE FRONT AS THE FIRST UPPER
JET LIFTS OFF TO THE NORTHEAST. THESE WILL CONTINUE TO LIFT OFF TO
THE NORTHEAST THIS MORNING...AND FOCUS FOR PRECIPITATION WILL TO
SHIFT INTO WESTERN PORTIONS OF THE FORECAST AREA THIS MORNING AS
MOISTURE AND LIFT INCREASES WITH THE NEXT IMPULSE AHEAD OF THE
ADVANCING SYSTEM. SO FAR...RAINFALL RATES OUT WEST DO NOT LOOK HEAVY
ENOUGH TO CAUSE CONCERNS FOR THE WEST FORK BURN SCAR...BUT THIS WILL
HAVE TO BE MONITORED CLOSELY THROUGH THE MORNING.
OF GREATER CONCERN WILL BE POTENTIAL FOR THUNDERSTORMS ACROSS THE
SOUTHEAST MOUNTAINS THIS AFTERNOON AS UPPER TROF LIFTS ACROSS THE
AREA DURING PEAK HEATING PERIOD. SFC LOW ACROSS SOUTHERN CO IS
PROGGED TO LIFT BACK NORTHWARD DURING THE AFTERNOON...WITH FRONTAL
BOUNDARY BECOMING THE FOCUS FOR STRONG TO EVEN SEVERE THUNDERSTORMS
THIS AFTERNOON AS IT LIFTS BACK NORTHWARD. VARIOUS SHORT RANGE
MODELS SHOW THIS LIFTING BACK NORTHWARD TO ALONG A LINE FROM
COLORADO SPRINGS TO EADS AS OF 21Z. DEPENDING ON SFC DEW
POINTS...CAPES COULD BE RUNNING ANYWHERE FROM 1000 J/KG TO 1500 J/KG
TO THE NORTH OF THIS BOUNDARY...AND WITH NEXT UPPER JET SHIFTING
NORTHWARD INTO THE REGION...COULD SEE DEEP LAYER SHEARS 40KTS...ESP
WHERE LOW LEVEL SFC WINDS REMAIN EASTERLY. SEEMS BEST THREAT AREA
FOR SEVERE POTENTIAL WILL BE ACROSS NORTHEAST EL PASO AND KIOWA
COUNTIES...AND POINTS TO THE NORTHEAST. LARGE HAIL AND DAMAGING
WINDS WILL BE THE PRIMARY STORM THREATS.
WITH UPPER LEVEL FORCING MOVING ACROSS DURING THE AFTERNOON...HIGH
RES AND CONCEPTUAL MODELS SUGGEST A LINE OF THUNDERSTORMS WILL
DEVELOP ACROSS THE SOUTHEAST MOUNTAINS AND MOVE OFF TO THE NORTHEAST
THROUGH THE AFTERNOON AND EARLY EVENING. LOCALLY HEAVY
RAINFALL...SMALL HAIL...AND ERRATIC GUSTY WINDS UP TO 50 MPH WILL BE
THE MAIN STORM THREATS. QUESTION IS...WILL THUNDERSTORMS BE CAPABLE
OF PRODUCING ENOUGH RAINFALL TO CAUSE FLASH FLOODING ON AREA BURN
SCARS. STORM MOTIONS TODAY WILL BE NORTH TO NORTHEAST AT AROUND 30-
35 MPH...WHICH SHOULD MITIGATE THIS THREAT SOME. HOWEVER THE WALDO
BURN SCAR WITH ITS VERY LOW FLASH FLOOD THRESHOLD LOOKS TO MOST
UNDER THE THREAT TODAY. IF SUFFICIENT HEATING CAN TAKE PLACE...WE
COULD SEE CAPES OF NEAR 1000 J/KG (WITH SFC DEW POINTS IN THE LOWER
50S). IF FRONTAL BOUNDARY LIFTS BACK NORTHWARD INTO THIS REGION AND
STALLS...THEN THIS COULD ALSO PROVIDE A FOCUS FOR A COUPLE OF ROUNDS
OF THUNDERSTORMS. HOWEVER...MODELS ARE NOT ALL IN AGREEMENT OF
WHERE THE HEAVIER PRECIPITATION WILL FALL. 06Z NAM12 IS THE
HEAVIEST HANDED WITH QPF AMOUNTS OF OVER AN INCH FALLING ACROSS
NORTHERN EL PASO AND TELLER COUNTIES DURING THE NOON TO 6 PM TIME
FRAME. HOWEVER RAP13...GFS...AND ECMWF ALL KEEP PRECIPITATION
AMOUNTS MUCH LIGHTER AROUND .25 TO CLOSE TO .50...AND ALL MODELS
SEEM TO POINT AT THE QPF MAXIMUM OCCURRING ACROSS NORTHEAST COLORADO
GIVEN THE CURRENT STORM TRACK. STILL CONTEMPLATING ISSUING A FLASH
FLOOD WATCH FOR WALDO BURN SCAR TODAY. SOME FACTORS THAT FAVOR
FLASH FLOODING TODAY FOR THE WALDO WOULD BE HIGHER PRECIPITABLE
WATERS...GOOD FORCING WITH SHORTWAVE MOVING ACROSS DURING THE
AFTERNOON...SOME POTENTIAL INSTABILITY IN THE AFTERNOON...AND EVEN A
BRIEF PERIOD OF SOUTHEAST UPSLOPE BEFORE 00Z. SOME FACTORS THAT DO
NOT PARTICULARLY FAVOR FLASH FLOOD POTENTIAL FOR WALDO INCLUDE FAST
STORM MOTIONS...EXTENSIVE MORNING CLOUD COVER...WARMING H5
TEMPERATURES AHEAD OF THE UPPER LOW TODAY...AND QUICK SHIFT TO A
SOUTHWEST DOWNSLOPE FLOW BY 00Z AS SYSTEM LIFTS TO THE NORTHEAST OF
THE AREA. WOULD LIKE TO SEE A FEW RUNS OF THE HRRR RESOLVE SOME OF
THESE MESOSCALE DETAILS BEFORE COMMITTING TO A WATCH. AM CONFIDENT
THAT SOMEWHERE CLOSE BY...LIKELY TO THE NORTHEAST OF THE BURN
SCAR...QPF AMOUNTS OF AN INCH OR MORE WILL BE POSSIBLE WITH THE
STRONGER STORMS. BUT NOT CONFIDENT ENOUGH THAT THIS WILL HAPPEN ON
WALDO TO GO WITH A WATCH. WILL CONTINUE TO MONITOR LATEST HIGH RES
MODELS THROUGH THE MORNING AND MAY HOIST A WATCH AS DETAILS BECOME
BETTER RESOLVED. REGARDLESS...ANYONE IN OR NEAR THE BURN SCARS TODAY
NEEDS TO MAINTAIN A HEIGHTENED AWARENESS OF THE WEATHER TODAY.
TIMEFRAME WITH THE GREATEST THREAT APPEARS TO BE BETWEEN NOON AND 6
PM.
THUNDERSTORMS WILL DIMINISH RAPIDLY THIS EVENING AS THE SYSTEM LIFTS
OFF TO THE NORTHEAST. SOME SHOWERS MAY LINGER ALONG THE CONTINENTAL
DIVIDE PAST MIDNIGHT AS THE NEXT UPPER TROF DROPS IN FROM THE
NORTHWEST. -KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 450 AM MDT FRI AUG 22 2014
PRIMARY LONGER TERM METEOROLOGICAL CHALLENGES INCLUDE
POPS...TEMPERATURES AND EVEN SOME GUSTY WINDS AT TIMES.
LATEST COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS SUGGEST
THAT ADEQUATE ATMOSPHERIC MOISTURE WILL INTERACT WITH SEVERAL
UPPER DISTURBANCES INTO THE MIDDLE PORTION OF NEXT WEEK. IN
ADDITION...A NORTHERLY SURGE IS PROJECTED TO PUSH ACROSS EASTERN
SECTIONS OF THE FORECAST DISTRICT TUESDAY NIGHT.
THE COMBINATION OF THESE FEATURES IS EXPECTED TO GENERATE
ISOLATED TO SCATTERED POPS AT TIMES OVER THE MAJORITY OF THE
FORECAST DISTRICT FROM FRIDAY INTO NEXT WEDNESDAY(ESPECIALLY IF
THE LATEST VERSION OF THE ECMWF IS CORRECT) WITH SOME DRYING
THEN ANTICIPATED BY LATER NEXT WEEK.
IN ADDITION...MAXIMUM AND MINIMUM TEMPERATURES ARE EXPECTED TO
RUN WITHIN A CATEGORY OR SO OF LATE AUGUST CLIMATOLOGICAL AVERAGES
DURING THE LONGER WHILE GUSTY GRADIENT WINDS WILL BE POSSIBLE AT
TIMES(PRIMARILY OVER FAR EASTERN SECTIONS) FROM SATURDAY INTO
SATURDAY NIGHT AND THEN AGAIN FROM SUNDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1054 AM MDT FRI AUG 22 2014
AN UPPER LEVEL STORM SYSTEM WILL MOVE ACROSS COLORADO THROUGH THIS
EVENING WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IMPACTING
ALL THREE TERMINALS. LOWERED CIGS AND VISIBILITIES ARE EXPECTED
THIS AFTERNOON AT ALL THREE TERMINALS...WITH LOCALLY HEAVY
RAINFALL EXPECTED. MODELS IN GOOD AGREEMENT WITH THE THUNDERSTORM
ACTIVITY ENDING AROUND 00Z/SAT AND GENERALLY FOLLOWED THIS TREND
IN THE TAFS. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOZLEY
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS PUEBLO CO
502 AM MDT FRI AUG 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM MDT FRI AUG 22 2014
...POTENT STORM SYSTEM TO WILL BRING FAST MOVING THUNDERSTORMS
CAPABLE OF LOCALLY HEAVY RAINFALL...SMALL HAIL...AND LIGHTNING TO
SOUTH CENTRAL AND SOUTHEAST COLORADO...WITH POTENTIAL FOR SEVERE
WEATHER FOR NORTHERN PORTIONS OF THE SOUTHEAST PLAINS BY AFTERNOON...
UPPER LOW OVER WESTERN AZ IS FORECAST TO EJECT TO THE NORTHEAST
TODAY...AS THE KICKER SYSTEM DROPS THROUGH THE PACIFIC NORTHWEST.
ALREADY HAVE A ROUND OF THUNDERSTORMS ONGOING ACROSS EAST CENTRAL
AND NORTHEAST COLORADO ALONG/NORTH OF THE FRONT AS THE FIRST UPPER
JET LIFTS OFF TO THE NORTHEAST. THESE WILL CONTINUE TO LIFT OFF TO
THE NORTHEAST THIS MORNING...AND FOCUS FOR PRECIPITATION WILL TO
SHIFT INTO WESTERN PORTIONS OF THE FORECAST AREA THIS MORNING AS
MOISTURE AND LIFT INCREASES WITH THE NEXT IMPULSE AHEAD OF THE
ADVANCING SYSTEM. SO FAR...RAINFALL RATES OUT WEST DO NOT LOOK HEAVY
ENOUGH TO CAUSE CONCERNS FOR THE WEST FORK BURN SCAR...BUT THIS WILL
HAVE TO BE MONITORED CLOSELY THROUGH THE MORNING.
OF GREATER CONCERN WILL BE POTENTIAL FOR THUNDERSTORMS ACROSS THE
SOUTHEAST MOUNTAINS THIS AFTERNOON AS UPPER TROF LIFTS ACROSS THE
AREA DURING PEAK HEATING PERIOD. SFC LOW ACROSS SOUTHERN CO IS
PROGGED TO LIFT BACK NORTHWARD DURING THE AFTERNOON...WITH FRONTAL
BOUNDARY BECOMING THE FOCUS FOR STRONG TO EVEN SEVERE THUNDERSTORMS
THIS AFTERNOON AS IT LIFTS BACK NORTHWARD. VARIOUS SHORT RANGE
MODELS SHOW THIS LIFTING BACK NORTHWARD TO ALONG A LINE FROM
COLORADO SPRINGS TO EADS AS OF 21Z. DEPENDING ON SFC DEW
POINTS...CAPES COULD BE RUNNING ANYWHERE FROM 1000 J/KG TO 1500 J/KG
TO THE NORTH OF THIS BOUNDARY...AND WITH NEXT UPPER JET SHIFTING
NORTHWARD INTO THE REGION...COULD SEE DEEP LAYER SHEARS 40KTS...ESP
WHERE LOW LEVEL SFC WINDS REMAIN EASTERLY. SEEMS BEST THREAT AREA
FOR SEVERE POTENTIAL WILL BE ACROSS NORTHEAST EL PASO AND KIOWA
COUNTIES...AND POINTS TO THE NORTHEAST. LARGE HAIL AND DAMAGING
WINDS WILL BE THE PRIMARY STORM THREATS.
WITH UPPER LEVEL FORCING MOVING ACROSS DURING THE AFTERNOON...HIGH
RES AND CONCEPTUAL MODELS SUGGEST A LINE OF THUNDERSTORMS WILL
DEVELOP ACROSS THE SOUTHEAST MOUNTAINS AND MOVE OFF TO THE NORTHEAST
THROUGH THE AFTERNOON AND EARLY EVENING. LOCALLY HEAVY
RAINFALL...SMALL HAIL...AND ERRATIC GUSTY WINDS UP TO 50 MPH WILL BE
THE MAIN STORM THREATS. QUESTION IS...WILL THUNDERSTORMS BE CAPABLE
OF PRODUCING ENOUGH RAINFALL TO CAUSE FLASH FLOODING ON AREA BURN
SCARS. STORM MOTIONS TODAY WILL BE NORTH TO NORTHEAST AT AROUND 30-
35 MPH...WHICH SHOULD MITIGATE THIS THREAT SOME. HOWEVER THE WALDO
BURN SCAR WITH ITS VERY LOW FLASH FLOOD THRESHOLD LOOKS TO MOST
UNDER THE THREAT TODAY. IF SUFFICIENT HEATING CAN TAKE PLACE...WE
COULD SEE CAPES OF NEAR 1000 J/KG (WITH SFC DEW POINTS IN THE LOWER
50S). IF FRONTAL BOUNDARY LIFTS BACK NORTHWARD INTO THIS REGION AND
STALLS...THEN THIS COULD ALSO PROVIDE A FOCUS FOR A COUPLE OF ROUNDS
OF THUNDERSTORMS. HOWEVER...MODELS ARE NOT ALL IN AGREEMENT OF
WHERE THE HEAVIER PRECIPITATION WILL FALL. 06Z NAM12 IS THE
HEAVIEST HANDED WITH QPF AMOUNTS OF OVER AN INCH FALLING ACROSS
NORTHERN EL PASO AND TELLER COUNTIES DURING THE NOON TO 6 PM TIME
FRAME. HOWEVER RAP13...GFS...AND ECMWF ALL KEEP PRECIPITATION
AMOUNTS MUCH LIGHTER AROUND .25 TO CLOSE TO .50...AND ALL MODELS
SEEM TO POINT AT THE QPF MAXIMUM OCCURRING ACROSS NORTHEAST COLORADO
GIVEN THE CURRENT STORM TRACK. STILL CONTEMPLATING ISSUING A FLASH
FLOOD WATCH FOR WALDO BURN SCAR TODAY. SOME FACTORS THAT FAVOR
FLASH FLOODING TODAY FOR THE WALDO WOULD BE HIGHER PRECIPITABLE
WATERS...GOOD FORCING WITH SHORTWAVE MOVING ACROSS DURING THE
AFTERNOON...SOME POTENTIAL INSTABILITY IN THE AFTERNOON...AND EVEN A
BRIEF PERIOD OF SOUTHEAST UPSLOPE BEFORE 00Z. SOME FACTORS THAT DO
NOT PARTICULARLY FAVOR FLASH FLOOD POTENTIAL FOR WALDO INCLUDE FAST
STORM MOTIONS...EXTENSIVE MORNING CLOUD COVER...WARMING H5
TEMPERATURES AHEAD OF THE UPPER LOW TODAY...AND QUICK SHIFT TO A
SOUTHWEST DOWNSLOPE FLOW BY 00Z AS SYSTEM LIFTS TO THE NORTHEAST OF
THE AREA. WOULD LIKE TO SEE A FEW RUNS OF THE HRRR RESOLVE SOME OF
THESE MESOSCALE DETAILS BEFORE COMMITTING TO A WATCH. AM CONFIDENT
THAT SOMEWHERE CLOSE BY...LIKELY TO THE NORTHEAST OF THE BURN
SCAR...QPF AMOUNTS OF AN INCH OR MORE WILL BE POSSIBLE WITH THE
STRONGER STORMS. BUT NOT CONFIDENT ENOUGH THAT THIS WILL HAPPEN ON
WALDO TO GO WITH A WATCH. WILL CONTINUE TO MONITOR LATEST HIGH RES
MODELS THROUGH THE MORNING AND MAY HOIST A WATCH AS DETAILS BECOME
BETTER RESOLVED. REGARDLESS...ANYONE IN OR NEAR THE BURN SCARS TODAY
NEEDS TO MAINTAIN A HEIGHTENED AWARENESS OF THE WEATHER TODAY.
TIMEFRAME WITH THE GREATEST THREAT APPEARS TO BE BETWEEN NOON AND 6
PM.
THUNDERSTORMS WILL DIMINISH RAPIDLY THIS EVENING AS THE SYSTEM LIFTS
OFF TO THE NORTHEAST. SOME SHOWERS MAY LINGER ALONG THE CONTINENTAL
DIVIDE PAST MIDNIGHT AS THE NEXT UPPER TROF DROPS IN FROM THE
NORTHWEST. -KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 450 AM MDT FRI AUG 22 2014
PRIMARY LONGER TERM METEOROLOGICAL CHALLENGES INCLUDE
POPS...TEMPERATURES AND EVEN SOME GUSTY WINDS AT TIMES.
LATEST COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS SUGGEST
THAT ADEQUATE ATMOSPHERIC MOISTURE WILL INTERACT WITH SEVERAL
UPPER DISTURBANCES INTO THE MIDDLE PORTION OF NEXT WEEK. IN
ADDITION...A NORTHERLY SURGE IS PROJECTED TO PUSH ACROSS EASTERN
SECTIONS OF THE FORECAST DISTRICT TUESDAY NIGHT.
THE COMBINATION OF THESE FEATURES IS EXPECTED TO GENERATE
ISOLATED TO SCATTERED POPS AT TIMES OVER THE MAJORITY OF THE
FORECAST DISTRICT FROM FRIDAY INTO NEXT WEDNESDAY(ESPECIALLY IF
THE LATEST VERSION OF THE ECMWF IS CORRECT) WITH SOME DRYING
THEN ANTICIPATED BY LATER NEXT WEEK.
IN ADDITION...MAXIMUM AND MINIMUM TEMPERATURES ARE EXPECTED TO
RUN WITHIN A CATEGORY OR SO OF LATE AUGUST CLIMATOLOGICAL AVERAGES
DURING THE LONGER WHILE GUSTY GRADIENT WINDS WILL BE POSSIBLE AT
TIMES(PRIMARILY OVER FAR EASTERN SECTIONS) FROM SATURDAY INTO
SATURDAY NIGHT AND THEN AGAIN FROM SUNDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 450 AM MDT FRI AUG 22 2014
OUTFLOW BOUNDARIES FROM THUNDERSTORMS TO THE NORTH WILL KEEP ERRATIC
GUSTY NORTH WINDS GUSTY ACROSS THE KCOS AND KPUB TERMINALS THIS
MORNING. WINDS WILL SHIFT AROUND TO THE EAST AND SOUTHEAST DURING
THE AFTERNOON. WIDESPREAD SHOWERS AND THUNDERSTORMS ALONG THE
CONTINENTAL DIVIDE THIS MORNING WILL SPREAD EASTWARD THROUGH THE
AFTERNOON. THIS WILL BRING LOWERING CIGS TO KALS THROUGH THE LATE
MORNING WITH THE POTENTIAL FOR AFTERNOON SHOWERS AND THUNDERSTORMS.
A LINE OF THUNDERSTORMS WILL DEVELOP ACROSS THE SOUTHEAST MOUNTAINS
AROUND 18Z...AND MOVE OFF INTO THE ADJACENT PLAINS AFFECTING THE
KCOS AND KPUB TERMINALS AFTER 19-20Z. THE MAIN STORM THREATS TODAY
WILL BE BRIEF MVFR TO IFR CONDITIONS WITH TSRA...SOME BRIEF SMALL
HAIL...AND ERRATIC WIND GUSTS TO 45 KTS. HOWEVER...A FEW STRONG TO
SEVERE STORMS WILL BE POSSIBLE...PARTICULARLY TO THE NORTH AND EAST
OF A LINE EXTENDING FROM KCOS TO EADS THIS AFTERNOON WHERE LARGE
HAIL AND WIND GUSTS TO 50 KTS OR BETTER WILL BE POSSIBLE.
THUNDERSTORMS SHOULD LIFT OFF TO THE NORTHEAST DURING THE EARLY
EVENING WITH -TSRA THREAT ENDING FOR ALL THREE TERMINALS BY 00Z-01Z.
-KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
430 PM EDT FRI AUG 22 2014
.SYNOPSIS...
AN UPPER LEVEL LOW OVER NEW ENGLAND WILL CONTINUE TO MOVE AWAY FROM
THE REGION TONIGHT...ENDING THE THREAT FOR SHOWERS. AS HIGH PRESSURE
BUILDS INTO THE AREA...IMPROVING CONDITIONS ARE EXPECTED OVER THE
WEEKEND...WITH GRADUALLY MORE AMOUNTS OF SUNSHINE AND WARMER
TEMPERATURES. WITH DRY WEATHER IN PLACE...ABOVE NORMAL TEMPERATURES
ARE EXPECTED FOR MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 430 PM EDT...AN UPPER LEVEL LOW IS SITUATED JUST EAST OF THE
AREA OVER EASTERN NEW ENGLAND. LOW LEVEL MOISTURE REMAINS HIGHS
OVER THE REGION WITH DEWPOINTS STILL IN THE 60S...AND PWAT VALUES
AROUND 1.50 INCHES. WEAK IMPULSES EMBEDDED WITHIN THE CYCLONIC
FLOW AROUND THIS UPPER LEVEL LOW ARE ALLOWING FOR PLENTY OF CLOUDS
AND SOME ON AND OFF RAIN SHOWERS. NO THUNDER HAS BEEN OCCURRING
DUE TO A LACK OF INSTABILITY THANKS TO THE THICK CLOUD COVER IN PLACE.
THE LATEST REGIONAL MOSAIC RADAR SHOWS THE MOST CONCENTRATED
ACTIVITY OF SHOWERS IS CURRENTLY SOUTHWEST OF THE AREA OVER
CENTRAL NY. THE SHOWERS HAVE BEEN RATHER SLOW MOVING TODAY DUE TO
THE LIGHT FLOW DUE TO THE UPPER LEVEL LOW NEARBY. THE LATEST 18Z
3KM HRRR MATCHES UP WELL WITH THE CURRENT RADAR...AND SHOWS A
DECREASING TREND IN THE COVERAGE AND INTENSITY OF RAIN SHOWERS
TOWARDS EVENING. AS THE UPPER LEVEL LOW STARTS TO MOVE AWAY...AND
DIURNAL INFLUENCES BEGAN TO WANE...THIS SEEMS TO MAKE SENSE...SO
HAVE DECREASED POPS FROM LIKELY AND HIGH CHANCE TO JUST SLIGHT TO
LOW CHC FOR THE OVERNIGHT HOURS.
WITH ALL THE LOW LEVEL MOISTURE IN PLACE...WILL KEEP CLOUDS IN
PLACE THROUGH THE DURATION OF THE OVERNIGHT HOURS. WILL ALSO ALLOW
FOR SOME PATCHY/AREAS OF FOG FOR VALLEY LOCATIONS FOR THE SECOND
HALF OF THE NIGHT AS WELL WITH ALL THE LOW LEVEL MOISTURE PRESENT.
OVERNIGHT LOWS LOOK TO RANGE FROM THE MID 50S TO LOW 60S.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
A DRYING AND WARMING TREND WILL TAKE PLACE THROUGH THE SHORT TERM
PERIOD. HIGH PRESSURE OVER SOUTHERN CANADA WILL BUILD SOUTHWARD
INTO THE REGION ON SATURDAY. WHILE THERE MAY BE A LINGERING RAIN
SHOWER ON SATURDAY /MAINLY FOR SOUTHERN OR HIGH TERRAIN
AREAS/...MOST AREAS WILL BE DRYING OUT. CLOUDS SHOULD BREAK FOR
SOME SUN FROM NORTH TO SOUTH DURING THE AFTERNOON HOURS...AS DRIER
AIR BEGINS TO WORK IN FROM SOUTHERN CANADA. MAX TEMPS LOOK TO
REACH THE 70S FOR MOST LOCATIONS.
DRY AND QUIET WEATHER WILL BE IN PLACE BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. OVERNIGHT LOWS LOOK TO BE IN THE 50S...AND DAYTIME
HIGHS ON SUNDAY LOOK TO REACH THE MID 70S TO LOW 80S. SKIES LOOK
TO BE MOSTLY CLEAR DURING THIS TIME PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A DRY START TO THE PERIOD FOLLOWED BY POSSIBLE POST-FRONTAL SHOWERS
TOWARD THE END OF THE WORK WEEK...THEN A RETURN TO DRY WEATHER FOR
THE START OF THE WEEKEND. SUNSHINE WILL BE PLENTIFUL THROUGH MID-
WEEK...WITH PARTLY TO MOSTLY CLOUDY SKIES THEREAFTER. HIGH
TEMPERATURE READINGS FROM MAINLY THE LOWER 70S TO MID 80S WILL BE
THE RULE MONDAY AND TUESDAY...WITH SLIGHTLY WARMER READINGS FOR
WEDNESDAY. BEHIND THE FRONT...THINGS COOL DOWN TO HIGHS FROM THE
MID 60S TO MID 70S BY FRIDAY. LOWS WILL BE PRIMARILY IN THE 50S OR
LOWER 60 UNTIL FRIDAY NIGHT...WHEN READINGS WILL RANGE FROM THE
UPPER 40S IN THE WESTERN ADIRONDACKS...TO AROUND 60 DEGREES IN THE
LOWER MID HUDSON VALLEY.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
PREDOMINATELY MVFR FLYING CONDITIONS WILL PREVAIL THROUGHOUT THE TAF
PERIOD AS SCATTERED DRIZZLE/SHOWERS FROM A SLOWLY DEPARTING LOW
PRESSURE SYSTEM CONTINUE TO AFFECT THE REGION.
THIS AFTERNOON...SCATTERED DRIZZLE/SHOWERS WILL CONTINUE INTO THE
EVENING HOURS RESULTING IN MVFR CEILINGS...WITH THE BEST CHANCE FOR
SHOWERS AT KALB THROUGH 20Z. HAVE INCLUDED A TEMPO GROUP AT KALB AS
WELL FROM 18Z TO 20Z TO ACCOUNT FOR BRIEF REDUCTIONS TO IFR CEILINGS
ASSOCIATED WITH NEARBY SHOWERS. ELSEWHERE EXPECT OCCASIONAL
DRIZZLE/MIST THAT MAY ALLOW FOR BRIEF REDUCTIONS TO MVFR
VISIBILITIES. WINDS WILL BE OUT OF THE EAST/SOUTHEAST AND LIGHT
AROUND 5 KNOTS.
TONIGHT INTO SATURDAY...MVFR CEILINGS WILL CONTINUE THROUGH THE
OVERNIGHT PERIOD WITH MVFR VISIBILITIES ALSO EXPECTED AFTER 06Z.
SHOWER ACTIVITY WILL GRADUALLY DECREASE DURING THE NIGHT AS WELL.
IFR CEILINGS WILL BE POSSIBLE AT KPSF AFTER 09Z BEFORE DRIER AIR
ALLOWS VFR FLYING CONDITIONS TO RETURN TO THE TAF SITES BY 15Z
SATURDAY...EXCEPT AT KPSF WHERE MVFR CEILINGS WILL CONTINUE THROUGH
AT LEAST 18Z SATURDAY. WINDS WILL BE LIGHT AND VARIABLE LESS THAN 5
KNOTS TONIGHT AND INTO SATURDAY.
OUTLOOK...
SATURDAY NIGHT THROUGH WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
SCATTERED SHOWERS INTO TONIGHT WILL KEEP FIRE WEATHER CONCERNS AT A
MINIMUM. RH VALUES WILL BE NEAR 100 PERCENT TONIGHT. WINDS WILL
GENERALLY BE LIGHT AND VARIABLE TONIGHT. TOMORROW...THE RH VALUES
WILL DROP TO 50 TO 60 PERCENT DURING THE AFTERNOON HOURS WITH
CLOUDS BREAKING FOR SOME SUNSHINE. THERE IS JUST A SLIGHT CHANCE
FOR A RAIN SHOWER OVER THE HIGH TERRAIN AND SOUTHERN PARTS OF THE
AREA. WINDS WILL CONTINUE TO BE LIGHT AND VARIABLE.
&&
.HYDROLOGY...
RECENT HEAVY RAINFALL LED TO FLOODING LAST NIGHT ACROSS PARTS OF
THE MOHAWK VALLEY...AND SMALLER RIVERS AND STREAMS CONTINUE TO BE
HIGH ACROSS THIS AREA DUE TO SHOWERS FROM THIS MORNING. THE
GROUND REMAINS RATHER SATURATED IN THE SACANDAGA AND SARATOGA
REGION AS WELL. ELSEWHERE...THERE HAVE BEEN PERIODS OF SHOWERS
FROM TIME TO TIME AS WELL...BUT RAINFALL AMOUNTS HAVEN/T BEEN
OVERLY EXCESSIVE.
THERE MAY BE A FEW ADDITIONAL RAIN SHOWERS BETWEEN LATE TONIGHT
AND INTO TONIGHT...BUT RAINFALL RATES ARE EXPECTED TO BE LIGHT FOR
THE MOST PART. THE ONLY WAY ANY ADDITIONAL FLOODING WOULD OCCUR
WOULD BE IF A HEAVY RAIN SHOWER HAPPENED TO SIT OVER A LOCATION
THAT SAW SIGNIFICANT RAINFALL LAST EVENING/NIGHT...OTHERWISE NO
ADDITIONAL FLOODING IS EXPECTED. THE COVERAGE OF SHOWERS WILL
DIMINISH BY LATER THIS EVENING.
THE ONLY RIVER POINT THAT IS CLOSE TO FLOOD STAGE IS THE
CANAJOHARIE CREEK AT CANAJOHARIE. THE RIVER HAS CRESTED JUST
BELOW FLOOD STAGE AFTER THIS MORNING/S ADDITIONAL BOUT OF
RAIN...AND LOOKS TO CONTINUE TO RECEDE. THE RECESSION MAY BE
SLOWED IF ADDITIONAL RAINFALL FALLS OVER THE BASIN...BUT THE
GENERAL TREND WILL BE TO FALL.
OVER THE WEEKEND AND INTO EARLY NEXT WEEK...A DRYING TREND WILL
BE IN PLACE...WITH JUST A SLIGHT CHANCE FOR A BRIEF LIGHT RAIN
SHOWER OVER THE HIGH TERRAIN ON SATURDAY. THIS WILL ALLOW FOR THE
GROUND TO DRY OUT...AND RIVER AND STREAM LEVELS TO SLOWLY RECEDE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...ELH
AVIATION...IRL
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
726 AM EDT FRI AUG 22 2014
.SYNOPSIS...
THE THREAT FOR SHOWERS WILL CONTINUE...ESPECIALLY ACROSS THE WEST
THROUGH TONIGHT. DRIER AND COOLER WEATHER FOLLOWS THIS WEEKEND. A
WARM-UP IS POSSIBLE NEXT WEEK PRIOR TO AN UNSETTLED PATTERN AHEAD
OF A FRONTAL BOUNDARY SWEEPING SOUTH OUT OF CANADA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
725 AM UPDATE...
LATEST RUNS OF THE HRRR APPEAR TO HAVE A GOOD HANDLE ON THE
SHOWERS THIS MORNING...AT LEAST IN TERMS OF THE OVERALL TRENDS.
AS SUCH...USED THE HRRR TO TWEAK POPS FOR THIS MORNING. ALSO
TWEAKED TEMPERATURES AND DEW POINTS TO REFLECT THE LATEST
OBSERVED TRENDS.
PREVIOUS DISCUSSION...
SHOWERS CONTINUE TO DEVELOP IN-SITU THIS MORNING ACROSS THE REGION
AS THE FIRST OF A SERIES OF VORT-MAX/S MOVES THROUGH THE REGION
EARLY THIS MORNING. PWATS ARE MARGINAL /AROUND TO JUST BELOW 1.5
INCHES/ WITH K-VALES IN THE W ABOUT 30-32. THEREFORE...SUSPECT
THIS THREAT FOR -SHRA TO CONTINUE THROUGH THE MORNING. ESPECIALLY
WERE WEAK CONVERGENT BOUNDARIES ARE ALLOWED TO FORM IN THE
RELATIVELY WEAK NEAR SFC FLOW. WILL CARRY POPS THROUGH MID DAY
MAINLY W OF THE WORCESTER HILLS INTO SRN NH...BUT WOULD NOT BE
SURPRISED TO SEE A FEW SHOWERS MAKE IT INTO THE BOS-PVD CORRIDOR.
OTHERWISE TODAY...THIS FIRST VORT MAX IS EXPECTED TO JOIN FORCES
WITH CUTOFF LOW PRES STALLED IN BLOCKING FLOW ACROSS ATLANTIC
CANADA...FORMING A HANGING TROF WHOSE BASE WILL REST TO THE S OF
REGION. NOTE THAT AS THIS TROF DEVELOPS AND A SERIES OF WEAKER
WAVES ROTATE THROUGH...HEIGHTS CONTINUE DECLINE INTO THE OVERNIGHT
HOURS. OVERALL COLUMN MOISTURE DOES ACTUALLY DIMINISH THROUGH THE
DAY...CLOSER TO BETWEEN 1.0-1.25 INCHES AND OVERALL INSTABILITY
/INCLUDING K-VALUES/ DIMINISH THROUGH THE DAY AS WELL. GIVEN
THIS...AND THE FACT THAT ANOTHER AXIS OF SFC BASED INSTABILITY
REMAINS TO THE W IN NY THANKS TO WHAT IS LIKELY TO BE MORE CLEAR
SKIES...AND CONTINUED MARINE INFLUENCE THANKS TO E COMPONENT TO
THE FLOW SUSPECT CONVECTIVE ACTIVITY TO ONCE AGAIN FIRE MAINLY W
OF NEW ENGLAND THIS AFTERNOON AND EVENING. THIS MAY ACTUALLY USURP
SOME OF THE AVAILABLE MOISTURE...SO WILL ACTUALLY HIGHLIGHT
DECLINING POPS THROUGH THE AFTERNOON...EXCEPT IN THE DUE TO
REMNANT CONVECTION ADVECTING E.
AS MENTIONED...EXPECT A LOT MORE WIDESPREAD CLOUD COVER TODAY
THANKS TO MARINE INFLUENCE AND COOLING TEMPS ALOFT.
THEREFORE...HIGHS MAY STRUGGLE TO MAKE IT OUT OF THE 60S IN SPOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT...
AM NOTING SIMILAR SETUP AS THU NIGHT. ANOTHER WEAK SHORTWAVE WILL
PUSH N-S ACROSS THE REGION AND PHASE WITH OFFSHORE LONGWAVE TROF
CONNECTED TO CUTOFF IN ATLANTIC CANADA. TWO CONDITIONS ARE
DIFFERENT HOWEVER...PWATS ARE A BIT LOWER /1.0-1.25 INCHES AS
OPPOSED TO 1.5/ AND K INDEX VALUES ARE LOWER AS DRIER AIR INTRUDES
THROUGH THE COLUMN FROM THE TOP DOWN. THEREFORE...SAVE FOR THE
ADVECTION OF LEFTOVER CONVECTION FROM THE W...SUSPECT THAT -SHRA
ARE LIKELY TO BE A BIT WEAKER AND LESS WIDESPREAD THAN THU NIGHT.
HOWEVER...WILL STILL MAINTAIN AT LEAST CHANCE POPS ESPECIALLY FOR
W AND NW PORTIONS OF THE FORECAST AREA.
ONE OTHER ISSUE IS FOG AND/OR LOW CIGS MOVING INTO E PORTIONS OF
THE FORECAST AREA. GUIDANCE CONTINUES TO NOTE AN AREA OF MOISTURE
BACKING IN FROM THE GULF OF MAINE OVERNIGHT THANKS TO CONTINUED
ELY COMPONENT OF THE FLOW. DO NOTE IN BUFKIT PROFILES THAT THERE
IS A LAYER OF DRY AIR ABOVE THE SFC WHICH MAY NEGATE FOG
DEVELOPMENT...ESPECIALLY IF STRATUS BACKS IN...LIMITING RADIATIVE
PROCESSES. THEREFORE...WILL MAINLY MENTION LOW CLOUDS...BUT MAY
NEED TO MONITOR FOR DRIZZLE WITH DRIER MOVING IN OVER MOISTURE
POOLING IN THE LOW-MID LVLS. SHOULD SOME AREAS RADIATE...FOG
REMAINS A RISK.
SAT...
ONE LAST PARTING SHOT FOR SHOWERS SAT AS SHORTWAVE ENERGY FORCES
SOME DIGGING AND SOUTHWARD PROGRESSION OF THE OFFSHORE LONGWAVE
TROF. LEFTOVER MOISTURE COMBINED WITH COOLING TEMPS ALOFT ARE
LIKELY TO LEAD TO A FAIR AMOUNT OF CLOUD COVER DURING THE EARLY
HALF OF THE DAY...ALONG WITH SHOWERS ESPECIALLY FROM PORTIONS OF
THE MERRIMACK VALLEY E AND POINTS SE. HOWEVER...IMPROVEMENT BY THE
AFTERNOON LOOKS POSSIBLE THANKS TO GRADUALLY RISING HEIGHTS FROM
THE S SHIFT IN THE TROF. THIS WILL ALLOW SFC INVERTED RIDGING TO
GRADUALLY REGAIN CONTROL ACROSS THE REGION TOWARD EVENING. IN
FACT...DESPITE THE CLOUDY START TO THE DAY...ITS POSSIBLE MANY
LOCATIONS STILL GET TO SEE THE SUNSET /EVEN IN THE E WHICH WILL
LIKELY TAKE THE LONGEST TO BREAK OUT/. HIGHS REMAIN ON THE COOL
SIDE OF NORMAL THANKS TO THE EARLY CLOUD COVER LIMITING DIURNAL
INFLUENCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...
* QUIET WEATHER EXPECTED THROUGH MUCH OF THIS PERIOD
* UNCERTAINTY INCREASES MIDDLE OF NEXT WEEK WITH AN APPROACHING
FRONT
21/00Z MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT TUESDAY. THEN
SIGNIFICANT DIFFERENCES ARISE FOR THE LATTER HALF OF NEXT WEEK...
MAKING FOR A LOWER CONFIDENCE FORECAST FROM THE MIDDLE OF NEXT WEEK
ONWARD.
A PERSISTENT UPPER LEVEL TROUGH OVER THE NORTHEAST WILL SLOWLY MAKE
ITS WAY EAST...MOVING JUST OFFSHORE THIS WEEKEND AS AN UPPER LEVEL
RIDGE TRIES TO PUSH NORTHEASTWARD FROM THE SOUTHERN USA. THIS UPPER
TROUGH IS RATHER PERSISTENT THOUGH...WITH EACH SUCCESSIVE MODEL RUN
LINGERING THIS TROUGH OVER THE NORTH ATLANTIC LONGER AND LONGER.
COOLER...LESS SEASONABLE WEATHER IS EXPECTED WHILE HIGH PRESSURE IN
QUEBEC WILL KEEP THINGS RELATIVELY DRY. STILL AGREE WITH THE
PREVIOUS FORECASTER...THINKING 21/00Z GUIDANCE CONTINUES TO STRUGGLE
WITH CONVECTIVE FEEDBACK INTO EARLY NEXT WEEK. AS SUCH...KEPT A DRY
FORECAST ACROSS MOST OF SOUTHERN NEW ENGLAND.
A HIGH PRESSURE WILL SINK SOUTH INTO EARLY NEXT WEEK...EVENTUALLY
MOVING SOUTH AND EAST OF SOUTHERN NEW ENGLAND AND RETURNING US TO A
MORE WESTERLY FLOW. A LOW PRESSURE IN ONTARIO MAY EVENTUALLY MOVE
EAST INTO QUEBEC...SWINGING A COLD FRONT THROUGH SOUTHERN NEW
ENGLAND WEDNESDAY OR THURSDAY. THIS IS WHERE MODELS START TO DIVERGE
MORE SIGNIFICANTLY.
THE ECMWF LOOKS A BIT QUICKER THAN THE GFS WITH THE APPROACH OF THIS
FRONT...BUT NEITHER IS AS PROGRESSIVE AS THE CANADIAN. WILL TAKE A
BLENDED APPROACH WITH THE TIMING FOR NOW. GIVEN THE STRENGTH OF THE
SURFACE RIDGE EXPECTED TO BE NEAR THE COAST...WOULD NOT BE OVERLY
SURPRISED IF THE ULTIMATE TIMING TURNS OUT TO BE SLOWER THAN THE
GFS. DEPENDING ON AVAILABLE MOISTURE...WE COULD SEE SOME SHOWERS AND
THUNDERSTORMS AHEAD OF THIS FRONT.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM...THROUGH SATURDAY...MODERATE CONFIDENCE.
TODAY INTO TONIGHT...
CONDITIONS IMPROVE TO VFR MOST LOCATIONS THROUGH THE DAY...
ALTHOUGH LOW VFR CIGS ARE LIKELY ESPECIALLY AREAS W OF THE
WORCESTER HILLS. SHOWERS LINGER IN THIS REGION AS WELL. BY
TONIGHT...SHOWERS DISSIPATE BUT THERE MAY BE MORE WIDESPREAD FOG
IN THE W AND THE POSSIBILITY OF LOWER CIGS IN THE E.
THEREFORE...COMPLEX OVERNIGHT SCENARIO...WHERE SOME OCCASIONAL
MVFR/IFR CONDITIONS ARE POSSIBLE.
SAT...
CONDITIONS IMPROVE TO VFR ALL LOCATIONS EXCEPT MAYBE AREAS E OF
THE WST-ORH-AFN...WHERE SOME MVFR CONDITIONS MAY LINGER INTO THE
DAY IN LOW CIGS. BY AFTERNOON...LIKELY TO SEE VFR ALL LOCATIONS.
KBOS TERMINAL...MODERATE CONFIDENCE. MAINLY VFR TODAY EXCEPT FOR
OCCASIONAL SHOWERS AND MVFR THIS MORNING. OVERNIGHT...EASTERLY
FLOW COULD YIELD A PERIOD OF LOW CLOUDS WITH MVFR/IFR CIGS
POSSIBLE. SHOULD THESE BE ESTABLISHED...ITS POSSIBLE THEY LINGER
INTO THE MORNING HOURS SAT.
KBDL TERMINAL...MODERATE CONFIDENCE. MVFR/VFR MAY BOUNCE BACK AND
FORTH THROUGH THE MORNING WITH SHOWERS. BY AFTERNOON...CONDITIONS
IMPROVE TO VFR AND MAY STAY THAT WAY THEREAFTER.
OUTLOOK...SATURDAY THROUGH TUESDAY...
HIGH CONFIDENCE VFR. LOW PROBABILITY OF PATCHY MVFR/IFR FOG EACH
NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM...THROUGH SATURDAY...HIGH CONFIDENCE.
E TO NE FLOW WILL CONTINUE INTO SAT AS HIGH PRES TO THE NE SLOWLY
REGAINS CONTROL. THROUGH THE DAY TODAY AND NIGHT TONIGHT...PERIODS
OF WIND GUSTS OF 15-20 KT ARE POSSIBLE AT TIMES WITH A SLOWLY
BUILDING SWELL. SEAS SHOULD REMAIN BELOW 4 FT EVEN ON THE SE AND S
WATERS. THEREFORE...NO SMALL CRAFT HEADLINES. SOME FOG AND SHOWERS
ARE POSSIBLE ON THE WATERS AT TIMES AS WELL...MAINLY THIS
MORNING...AND ONCE AGAIN OVERNIGHT.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
HIGH CONFIDENCE.
HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED FOR MUCH OF THIS
PERIOD WITH HIGH PRESSURE ACROSS THE REGION. SEAS COULD APPROACH 5
FT ACROSS THE OUTERMOST SOUTHERN COASTAL WATERS THIS WEEKEND. NOT
ENOUGH CONFIDENCE TO ISSUE A SMALL CRAFT ADVISORY THOUGH. LOW
PROBABILITY OF PATCHY OVERNIGHT FOG LIMITING VISIBILITIES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...BELK/DOODY
SHORT TERM...DOODY
LONG TERM...BELK
AVIATION...BELK/DOODY
MARINE...BELK/DOODY
AREA FORECAST DISCUSSION
NWS TAUNTON MA
147 AM EDT FRI AUG 22 2014
.SYNOPSIS...
SHOWERS CONTINUING ACROSS WESTERN NEW ENGLAND OVERNIGHT INTO
FRIDAY...DISSOLVING SOUTHWEST AS HIGH PRESSURE BUILDS IN FROM THE
NORTH. HIGH PRESSURE OUT OF THE MARITIMES WILL BRING DRIER AND
COOLER CONDITIONS THIS WEEKEND. MILDER TEMPERATURES WILL RETURN
EARLY NEXT WEEK. UNSETTLED CONDITIONS MAY RETURN LATE WEDNESDAY OR
NEXT THURSDAY AS A FRONT MAY APPROACH OUT OF QUEBEC.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
10 PM UPDATE...
WV IMAGERY SHOWS WEAKENED UPPER LVL CUTOFF VORTMAX NOW SLIDING SE
THROUGH NY INTO PA/NJ THIS EVENING. LATEST RAP ALSO SHOWS THAT
AXIS OF LEFTOVER INSTABILITY RESIDES TO THE W AS WELL. HENCE WHY
MUCH OF THE CONVECTIVE ACTIVITY IS TAKING ON A MORE N-S
PROPAGATION THIS EVENING AND WHY ONLY LEFTOVER CONVECTION IN THE
FORM OF LIGHT-MOD -SHRA ARE MAKING IT/S WAY INTO THE WRN ZONES.
FEEL THIS WILL CONTINUE TO BE THE TREND MUCH OF THE
NIGHT...ALTHOUGH EXPECT THAT THE BULK OF THE STRONGER CONVECTION
IS LIKELY TO WEAKEN WITH THE LOSS OF HEATING.
ELSEWHERE...FURTHER E...SPOTTY -SHRA CONTINUE TO FORM AHEAD OF THE
VORTMAX ALONG AN AXIS OF 30+ K-INDEX VALUES SUGGESTIVE OF MODERATE
COLUMN MOISTURE IN THE LOW-MID LVLS AND JUST ENOUGH CONDITIONAL
INSTABILITY TO SUPPORT THE LIFT PROVIDED BY THE APPROACHING WAVE.
THESE ARE LIKELY TO CONTINUE FORMING IN-SITU ACROSS THE
REGION...SO AN AXIS OF HIGH CHANCE TO LOW LIKELY POPS WILL BE
USED. SOME OF THESE ARE LIKELY TO HOLD TOGETHER INTO THE
PROVIDENCE-BOSTON CORRIDOR AS WELL.
PREVIOUS DISCUSSION...
TONIGHT...
LOW TRANSITIONS AS AN OPEN WAVE LOW TOWARDS THE SE. ACCOMPANYING
MAIN CRUX OF ENERGY YIELDS ASCENT OF AVAILABLE MOISTURE FUELED BY
A SW-PLUME OF HIGHER THETA-E AIR WRAPPING AHEAD OF THE LOW /1.5
PWAT AIRMASS/ CONVERGING AGAINST HIGH PRESSURE AND DRY AIR
BUILDING SW BELOW H8. THIS YIELDS NW-SE ORIENTED AREAS OF F-GEN
FORCING WITHIN THE LOW-LEVELS THAT WILL LIKELY PARENT WITH MID-
LEVEL FORCING.
A CONSENSUS WEIGHTING OF MODEL GUIDANCE PUTS THE LIKELIHOOD OF
SHOWERS TOWARDS THE W/SW FORECAST ZONE WHICH WOULD BE EXPECTED BUT
CAN NOT RULE OUT OF CHANCE OF SHOWERS ELSEWHERE. ONLY THE
IMMEDIATE E/SE MAY BE SPARED OF WET WEATHER...BUT AM NOT HOLDING
MY BREATH. LOW CONFIDENCE OF THUNDER WITH THE STABLE ENVIRONMENT.
WILL NEED TO MONITOR FOR FOG AND LOW CLOUDS. HIGHEST CONFIDENCE
IS IN AREAS OF STRONG LOW-LEVEL CONVERGENCE AND SHOWERS...
ESPECIALLY ACROSS THE HIGHER TERRAIN. YET WITH E-ONSHORE FLOW
DRIVING IN HIGHER DEWPOINT AIR...ALONG WITH THE GREATER CAPACITY
FOR AREAS TO RADIATE EFFICIENTLY THE LAST COUPLE OF NIGHTS...FOG
AND LOW CLOUDS MAY BE POSSIBLE FOR E/SE PORTIONS OF NEW ENGLAND.
INCREASING CLOUDS FROM THE W MAY COMPLICATE THE MATTER.
WILL GO WITH LOWS AROUND THE UPPER-50S TO LOW-60S WITH THE COOL
SPOTS TO THE N/W WHICH BARELY SAW ANY SUN...AND THE E/SE IMMEDIATE
INTERIOR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
FRIDAY...
WITH THE LOW SWUNG SE OF THE REGION...CUTOFF ENERGY WRAPS REARWARD
AND SE INTO THE REGION INVOKING A HANGING TROUGH. RISING HEIGHTS IN
WAKE OF THE TROUGH ALLOW FOR ENHANCED RIDGING OF HIGH PRESSURE SW
AHEAD OF WHICH F-GEN FORCING IS MAXIMIZED WITHIN THE LOW-LEVELS.
PARENTING WITH MID-LEVEL ASCENT PER CUTOFF ENERGY...THERE IS THE
LIKELIHOOD FOR CONTINUED SHOWERY WEATHER OVER SW PORTIONS OF NEW
ENGLAND.
WILL HOLD WITH LIKELY POPS ACROSS FAR W/SW PORTIONS OF THE
FORECAST AREA BENEATH AN ABUNDANCE OF CLOUDS. AM NOT GOING TO GET
SPECIFIC WITH THE FORECAST POPS BUT RATHER BROAD BRUSH AN AREA
WHERE THERE IS HIGHEST CONFIDENCE. CHANCE TO SLIGHT CHANCE POPS E.
COMBINATION OF CLOUDS AND RAIN COULD MAKE FOR A VERY CHILL DAY
ESPECIALLY FOR MID- TO LATE-AUGUST. THE DREARY WEATHER COULD YIELD
HIGHS AROUND THE LOW- TO MID-60S FOR THE S/W...WARMER E WHERE THE
GREATER CHANCE OF SEEING SOME SUNSHINE YET ONLY INTO THE UPPER-60S
WITH THE BRISK ONSHORE E-FLOW SURGING INTO INTERIOR NEW ENGLAND.
FRIDAY NIGHT...
ACTIVITY SHOULD DIMINISH WITH SUBSIDENCE AND DRY AIR BUILDING SW AS
HEIGHTS RISE IN RESPONSE TO THE HANGING TROUGH SWINGING S/E. LOW-
LEVEL F-GEN FORCING AND MID-LEVEL FORCING SHOULD CONTINUE TO PUSH SW
INTO NY/PA AHEAD OF CONTINUED RIDGE ENHANCEMENT.
WHILE CONSENSUS WEIGHTING OF MODEL GUIDANCE YIELDS A SLIGHT CHANCE
OF SHOWERS FOR S/W PORTIONS OF THE FORECAST AREA...THE LONG E-FETCH
OFF THE WATERS LIKELY RESULTING IN MOISTURE POOLING WITHIN THE LOW-
LEVELS COULD RESULT IN LOW CLOUDS AND FOG...PERHAPS EVEN DRIZZLE AS
THE FLOW UNDERGOES OROGRAPHIC LIFT ALONG THE E-SHORELINE.
A TOUGH FORECAST AND A LIKELY COOL AND DREARY NIGHT WITH LOWS
GETTING DOWN AROUND THE MID-50S. WITH DEWPOINTS AT SIMILAR VALUES...
ANTICIPATING A PLETHORA OF PATCHY DENSE FOG WHERE THE E-FLOW IS
LIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...
* QUIET WEATHER EXPECTED THROUGH MUCH OF THIS PERIOD
* MILDER TEMPERATURES WILL RETURN MONDAY AND TUESDAY AS RIDGE TRIES
TO BUILD EAST
* TIMING OF APPROACHING FRONT BY LATE NEXT WEEK REMAINS UNCERTAIN
BLOCKING UPPER LEVEL PATTERN LOOKS TO REMAIN IN PLACE ACROSS NORTH
AMERICA AS H5 CUTOFF LOW PRES REMAINS PERSISTENT S OF GREENLAND
THROUGH MOST IF NOT ALL OF THE LONG TERM PERIOD. SOME QUESTIONS DO
COME INTO PLAY AS THE NORTHERN STREAM UPPER FLOW TRIES TO
RECONFIGURE EARLY NEXT WEEK. NW FLOW TRIES TO FLATTEN OUT LATER THIS
WEEKEND...THEN UPPER LEVEL RIDGING APPEARS TO BUILD IN BRIEFLY
AROUND MONDAY OR TUESDAY. OPERATIONAL MODEL RUN DIFFERENCES MAY BE
RESOLVING...BUT STILL SOME TIMING ISSUES CONTINUE LATE NEXT WEEK.
THIS LENDS TO LOWER FORECAST CONFIDENCE BEYOND TUESDAY.
DETAILS...
SATURDAY AND SUNDAY...
EXPECT HIGH PRES RIDGING TO CONTINUE TO NOSE IN FROM THE MARITIMES.
THE ORIENTATION OF THIS RIDGE WILL KEEP COOL ONSHORE WINDS. SEVERAL
OPERATIONAL MODEL SOLUTIONS...MAINLY THE 12Z GFS/ECMWF...TRY TO WORK
CLOUDS AND SOME LIGHT PRECIP OFF THE OCEAN DURING SAT WITH LONG
FETCH OFF THE GULF OF MAINE. CAN NOT RULE OUT ISOLD SHOWERS THAT MAY
MOVE ONSHORE SATURDAY MORNING THEN PUSH W. COULD EVEN SEE SOME LIGHT
DRIZZLE AROUND SUNRISE ALONG THE IMMEDIATE COAST. HAVE MENTIONED
ONLY SLIGHT CHANCE POPS AT THIS POINT...THOUGH...BECAUSE OF
UNCERTAINTY OF HOW MUCH MOISTURE WILL BE REALIZED. ONE CERTAINTY
THOUGH IS THAT COOLER THAN NORMAL TEMPS WILL REMAIN WITH THE ONSHORE
WINDS THROUGH THE WEEKEND.
MONDAY AND TUESDAY...
LOOKS LIKE THE MARITIMES RIDGE AXIS TRIES TO PUSH OFFSHORE AS H5
RIDGE PUSHES SE OUT OF ONTARIO AND THE GREAT LAKES AND ACTUALLY
BUILDS INTO QUEBEC...A SET UP THAT HAS BEEN RARE THIS SUMMER. WILL
REMAIN DRY BUT LOOKS LIKE MILDER TEMPS ON THE HORIZON AS WINDS BACK
AROUND TO W AND SW. TEMPS LOOK BE CLOSE TO SEASONAL NORMS FOR LATE
AUGUST...THOUGH WILL REMAIN A BIT COOLER ALONG THE S COAST. HUMIDITY
WILL ALSO START TO INCREASE DURING TUESDAY.
WEDNESDAY AND THURSDAY...
WHILE THE LAST SEVERAL ECMWF OP RUNS HAVE BEEN MUCH FASTER THAN THE
COUNTERPART GFS...THE 12Z RUN LOOKS MUCH CLOSER WITH ITS SOLUTION IN
KEEPING RIDGING ACROSS MOST OF THE EASTERN SEABOARD. ONE BIG FLY IN
THE OINTMENT IS THE POSSIBILITY OF A SYSTEM THAT WILL TRY TO MAKE
THE TURN AROUND THE SUBTROPICAL RIDGE OFFSHORE...BUT THAT IS HIGHLY
UNCERTAIN. WEAK COLD FRONT MAY STILL TRY TO WORK OUT OF QUEBEC LAST
WED OR THU...THEN COULD STALL SOMEWHERE ACROSS THE REGION. STILL A
TOUGH CALL. ALSO...DEPENDING UPON AVAILABLE MOISTURE AND
INSTABILITY...MIGHT SEE SOME SHOWERS AND/OR THUNDERSTORMS IN
VICINITY OF THE FRONT. LEANED TOWARD A BLEND OF THE 12Z GFS RUN
ALONG WITH GFS/EC ENSEMBLES FOR THIS PORTION OF THE FORECAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM...THROUGH SATURDAY...MODERATE CONFIDENCE.
THROUGH 12Z...
A FEW SHOWERS ACROSS THE REGION THROUGH THE MORNING...ESPECIALLY
ACROSS SRN NH AND POINTS W OF THE WORCESTER HILLS. THESE ARE THE
MOST LIKELY SPOTS TO EXPERIENCE MVFR CONDITIONS. VFR DOMINATES
ELSEWHERE...EXCEPT ACK...WHERE IFR CIGS LINGER THROUGH THE
MORNING.
TODAY INTO TONIGHT...
CONDITIONS IMPROVE TO VFR MOST LOCATIONS THROUGH THE DAY ALTHOUGH
LOW VFR CIGS ARE LIKELY ESPECIALLY AREAS W OF THE WORCESTER
HILLS. SHOWERS LINGER IN THIS REGION AS WELL. BY TONIGHT...SHOWERS
DISSIPATE BUT THERE MAY BE MORE WIDESPREAD FOG IN THE W AND THE
POSSIBILITY OF LOWER CIGS IN THE E. THEREFORE...COMPLEX OVERNIGHT
SCENARIO...WHERE SOME OCCASIONAL MVFR/IFR CONDITIONS ARE POSSIBLE.
SAT...
CONDITIONS IMPROVE TO VFR ALL LOCATIONS EXCEPT MAYBE AREAS E OF
THE WST-ORH-AFN...WHERE SOME MVFR CONDITIONS MAY LINGER INTO THE
DAY IN LOW CIGS. BY AFTERNOON...LIKELY TO SEE VFR ALL LOCATIONS.
KBOS TERMINAL...MODERATE CONFIDENCE. MAINLY VFR TODAY EXCEPT FOR
OCCASIONAL SHOWERS EARLY THIS MORNING. OVERNIGHT...EASTERLY FLOW
COULD YIELD A PERIOD OF LOW CLOUDS WITH MVFR/IFR CIGS POSSIBLE.
SHOULD THESE BE ESTABLISHED...ITS POSSIBLE THEY LINGER INTO THE
MORNING HOURS SAT.
KBDL TERMINAL...MODERATE CONFIDENCE. MVFR/VFR MAY BOUNCE BACK AND
FORTH THROUGH THE MORNING WITH SHOWERS. BY AFTERNOON...CONDITIONS
IMPROVE TO VFR AND MAY STAY THAT WAY THEREAFTER.
OUTLOOK...SATURDAY THROUGH TUESDAY...
HIGH CONFIDENCE FOR VFR. LOW PROBABILITY OF PATCHY FOG WITH BRIEF
LOCAL MVFR-IFR CONDITIONS EACH NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM...THROUGH FRIDAY...MODERATE CONFIDENCE.
NE-WINDS INCREASING IN RESPONSE TO INTERIOR LOW PRESSURE SHIFTING
SE ACROSS THE WATERS WITH SOME MILD STRENGTHENING AS HIGH PRESSURE
BUILDS IN FROM THE N. SUBSEQUENT PRESSURE-GRADIENT MAY YIELD SOME
DECENT FETCH WITH GUSTS UP TO 20 KTS TO CAUSE SEAS TO RISE...BUT
WILL HOLD AT 4 FEET. FEEL BRISK WINDS WILL DIMINISH FOG POTENTIAL
YET LOW CLOUDS AND SHOWERS MAY BE AN ISSUE FOR AREAS TOWARDS THE
SW.
OUTLOOK...SATURDAY THROUGH TUESDAY...
HIGH CONFIDENCE.
EXPECT WINDS AND SEAS BELOW SMALL CRAFT CRITERIA THROUGH THE PERIOD.
THERE IS A CHANCE THAT E SWELLS COULD BUILD CLOSE TO 5 FT ON THE
OUTER WATERS THIS WEEKEND WITH LONG E FETCH...EVEN WITH WIND SPEEDS
LESS THAN 15 KT. MAY SEE PATCHY OVERNIGHT FOG REDUCING VISIBILITIES
EACH NIGHT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SIPPRELL/EVT
NEAR TERM...DOODY/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...EVT
AVIATION...DOODY/EVT
MARINE...SIPPRELL/EVT
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1042 PM EDT SAT AUG 23 2014
.UPDATE...
COMPLEX OF SHOWERS/TSTORMS OVER SRN KY/NRN TN WAS PROGRESSING SOUTH.
THIS AREA IS DIMINISHING IN SIZE AND COVERAGE...HOWEVER EACH RUN OF
THE HRRR BRINGS IT CLOSER TO THE GA BORDER AFTER MIDNIGHT. WILL
THEREFORE INCREASE POPS TO CHANCE POPS ACROSS EXTREME NORTH GA AFTER
MIDNIGHT. NO OTHER CHANGES PLANNED.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
/ISSUED AT 346 PM EDT SAT AUG 23 2014/
NO CHANGES PLANNED TO THE CURRENT HEAT ADVISORY HEADLINE THIS
AFTERNOON. TEMPERATURES ARE EXPECTED TO BE COOLER TOMORROW...SO NO
EXTENSION INTO SUNDAY IS PLANNED AT THIS TIME.
19Z SURFACE ANALYSIS SHOWS A WEAK TROUGH ACROSS NE GA...WHILE HIGH
PRESSURE IS CENTERED ACROSS THE GULF STATES. 500MB ANALYSIS SHOWS A
WEAK SHORTWAVE DIVING SOUTH ACROSS WESTERN GA THIS AFTERNOON. THIS
SHORTWAVE HAS HELPED INITIATE AND SUSTAIN SOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS NORTHERN GA THIS AFTERNOON. LATEST RUNS OF THE
HRRR KEEP CONVECTION GOING...ESPECIALLY ACROSS NW GA...INTO THE
EVENING HOURS AS THE SHORTWAVE CONTINUES TO IMPACT THE CWFA. DO
EXPECT CONVECTION TO BEGIN DIMINISHING BY THE LATE EVENING.
MODELS HAVE BEEN PERSISTENT IN BRINGING A BACKDOOR FRONTAL BOUNDARY
INTO NE GA TOMORROW. THE SURFACE FLOW WILL SWITCH AROUND TO THE EAST
OVERNIGHT...AND LOW LEVEL MOISTURE WILL BEGIN TO INCREASE ALONG AND
JUST AHEAD OF THE APPROACHING BOUNDARY. MODELS HAVE ALSO BEEN VERY
CONSISTENT IN PRODUCING HIGH POPS FOR THIS PERIOD. WITH THE
INCREASED CLOUD COVER AND PRECIPITATION...TEMPERATURES ACROSS THE
NORTHERN CWFA WILL BE SEVERAL DEGREES COOLER THAN TODAYS READINGS.
TEMPERATURES ACROSS THE SOUTHERN CWFA WILL HEAVILY DEPEND UPON HOW
FAR SOUTH THE BOUNDARY MAKES IT. MADE SOME MINOR TWEAKS TO THE
PRECIP TIMING...BUT OVERALL...NO MAJOR CHANGES TO THE POPS.
MODELS ARE DIMINISHING PRECIP CHANGES DURING THE EVENING HOURS.
HAVENT MADE MANY CHANGES TO THE SUNDAY NIGHT PERIOD.
NLISTEMAA
.LONG TERM /MONDAY THROUGH SATURDAY/...
/ISSUED AT 346 PM EDT SAT AUG 23 2014/
PATTERN IN BEGINNING OF LONG TERM PERIOD DOMINATED BY LARGE
POSITIVELY TILTED UPPER RIDGE OVER ALL SOUTHERN AND EASTERN STATES
WITH TROUGH ON EITHER SIDE...ONE OVER WESTERN CONUS AND ANOTHER
HIGHLY POSITIVELY TILTED TROUGH IN THE WESTERN ATLANTIC
PARALLELING THE EAST COAST. 12Z MED RANGE MODELS EXPANDS SOUTH AND
EAST CONUS RIDGE THRU EARLY WED WHILE PIECE OF WESTERN ATLANTIC
TROUGH DIPS SOUTH TOWARDS DEVELOPING TROPICAL SYSTEM. QUITE A
COMPLICATED PATTERN AND MAKES FORECASTING TRACK OF INVEST 96L
PROBLEMATIC. BY THURS...PATTERN BECOMES MORE ZONAL WITH BROAD
TROUGH OVER THE CENTRAL US AND BROAD RIDGES OVER THE WEST AND
EAST. 12Z GFS IS SLOWER WITH THE CENTRAL US TROUGH WHICH GIVES
A MORE WESTERN TRACK TO 96L...WHICH BASED ON RECENT MODEL RUNS AND
CONTINUED HIGH PROBABILITIES FROM NHC OUTLOOKS WILL LIKELY BECOME
TS CRISTOBAL. 12Z ECMWF SLIGHTLY MORE NORTHERN TRACK BUT BOTH
MODELS COMING INTO SIGNIFICANTLY BETTER AGREEMENT.
AS LONG AS TRACK DOES NOT SHIFT DRAMATICALLY WEST AND SOUTH FROM
CURRENT TRACK...IMPACT TO THE AREA WILL BE MINIMAL WITH DEEP DRY
AIRMASS AND SLIGHTLY STRONGER SFC WINDS.
COULD SEE ISOLD SHRA/TSRA BY THURS-FRI AS SLOW-MOVING CENTRAL US
TROUGH APPROACHES REGION FROM THE WEST.
SNELSON
PREV LONG TERM DISCUSSION /SUNDAY NIGHT THROUGH FRIDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
UPPER RIDGE CONTINUES TO DOMINATE AT THE BEGINNING OF THE
EXTENDED...WHILE SFC RIDGE BUILDS ACROSS THE MID ATLANTIC AND
DOWN THE APPALACHIANS. WITH THE PSEUDO WEDGE BUILDING IN...WINDS
BECOME EASTERLY AND CLOUD COVERAGE REMAINS BKN AT LEAST INITIALLY.
CLOUD COVERAGE DOES HELP TO KEEP TEMPS ON THE COOLER SIDE ON
MONDAY. DRIER AIR MOVES IN FOR THE FIRST HALF OF THE WEEK /BEHIND
THE BACKDOOR FRONT/. WITH THIS...DO NOT HAVE MOISTURE AROUND FOR
MUCH IN TERMS OF PRECIP AND THUS HAVE LIMITED POPS TO NO MENTION
OR SLIGHT CHANCE. DIFFERENCES EXIST BETWEEN THE GFS AND ECMWF IN
THE SECOND HALF THE OF THE EXTENDED. GFS BRINGS A COLD FRONT INTO
THE AREA ON FRIDAY...WHILE THE ECMWF KEEPS AN UPPER RIDGE ACROSS
THE SOUTHEAST. HAVE TENDED MORE TOWARDS THE GFS AND SHOWN AN
INCREASE IN CLOUDS/PRECIP FOR FRIDAY ASSOCIATED WITH THE FRONT.
DIFFERENCES ALSO EXIST STILL WITH HOW THE MODELS ARE HANDLING THE
POTENTIAL TROPICAL SYSTEM NEXT WEEK. GFS REMAINS FURTHER WEST AND
SLOWER WHILE THE ECMWF IS FURTHER EAST /ALTHOUGH LATEST RUN IS
WEST OF PREVIOUS RUN/ AND FASTER. NEITHER 00Z SOLUTION BRINGS
IMPACTS TO THE CWA...BUT REGARDLESS...STILL FAR OUT IN THE
FORECAST AND ITS SOMETHING THAT NEEDS TO BE WATCHED AS WE HEAD
INTO NEXT WEEK.
11
&&
.AVIATION...
00Z UPDATE...
CONVECTION OVER NORTH GA IS SLOWLY DISSIPATING AND SHOULD NOT AFFECT
ANY TAF SITES THIS EVENING. BACK DOOR FRONT WILL ENTER NORTHEAST GA
SHORTLY AFTER MIDNIGHT AND MOVE ACROSS THE FORECAST AREA AND INTO AL
BY 12Z. MVFR CIGS WILL MOVE INTO NORTHEAST GA LATE TONIGHT...AND
POSSIBLY INTO THE ATL AREA. SHOULD ALSO SEE AN INCREASE IN SHOWERS
SUNDAY MORNING WITH SCATTERED TSRA IN THE AFTERNOON OVER
ATL/MCN/CSG. ONCE WINDS BECOME NORTHEAST AFTER THE FROPA...THEY
SHOULD STAY NORTHEAST FOR THE REST OF THE FORECAST.
//ATL CONFIDENCE...00Z UPDATE...
HIGH CONFIDENCE ALL ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 74 89 70 87 / 40 60 40 10
ATLANTA 76 90 72 86 / 30 60 40 20
BLAIRSVILLE 68 83 66 82 / 40 60 40 20
CARTERSVILLE 73 91 72 87 / 30 60 40 20
COLUMBUS 79 95 74 88 / 20 60 40 20
GAINESVILLE 73 87 70 84 / 40 60 40 20
MACON 77 94 72 88 / 20 60 40 10
ROME 74 92 73 88 / 40 60 40 20
PEACHTREE CITY 75 91 72 87 / 20 60 40 20
VIDALIA 77 93 72 89 / 20 60 50 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BALDWIN...BIBB...BLECKLEY...CHATTAHOOCHEE...CLARKE...
CRAWFORD...CRISP...DODGE...DOOLY...EMANUEL...GLASCOCK...GREENE...
HANCOCK...HOUSTON...JASPER...JEFFERSON...JOHNSON...JONES...
LAMAR...LAURENS...MACON...MARION...MONROE...MONTGOMERY...
MORGAN...MUSCOGEE...OCONEE...OGLETHORPE...PEACH...PULASKI...
PUTNAM...SCHLEY...STEWART...SUMTER...TALBOT...TALIAFERRO...
TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TWIGGS...UPSON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...WILKINSON.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....SNELSON
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
618 PM EDT FRI AUG 22 2014
.SYNOPSIS...
A BACK DOOR COLD FRONT WILL THROUGH THE NORTHERN AND CENTRAL
MIDLANDS SATURDAY...AND SHIFT TOWARDS THE CSRA SUNDAY. THIS WILL
LEAD TO A CHANCE OF THUNDERSTORMS ALONG AND AHEAD OF THE
FRONT...WITH TEMPERATURES RETURNING TO MORE NORMAL LEVELS BEHIND
IT. THE FRONT WILL LINGER SOUTH OF THE CSRA EARLY TO MID NEXT
WEEK...LEADING TO GENERALLY FAIR WEATHER WITH NEAR NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH SATURDAY/...
88D REGIONAL COMPOSITE SHOWS A FEW ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS THE UPSTATE...PEE DEE AND CENTRAL GEORGIA.
ATMOSPHERE REMAINS CAPPED ACROSS THE MIDLANDS AND AIRMASS IS
DRIER WITH DEWPOINT TEMPERATURES IN THE UPPER 50S TO MIDDLE 60S.
ONLY EXPECT AN ISOLATED SHRA/TSRA THROUGH EARLY EVENING. FORECAST
AGRESS WELL WITH HRRR AS IT SHOWS ANY ACTIVITY REMAINING NORTH OF
THE CWA.
SURFACE LOW PRESSURE ALONG THE VA COAST IS FORECAST TO MOVE
SOUTHWARD OVERNIGHT INTO EASTERN NC. THIS WILL ALLOW A BACKDOOR
COLD FRONT TO APPROACH THE NORTHERN MIDLANDS AROUND DAYBREAK
SATURDAY. KEPT OVERNIGHT LOWS NEAR CONSENSUS IN THE LOWER AND
MIDDLE 70S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
MAIN ISSUE FOR SATURDAY AND INTO SUNDAY IS TIMING OF APPROACHING
BACK DOOR FRONT. THINK PRE-FRONTAL TROUGH SETS UP ACROSS SOUTHERN
CWA SATURDAY WITH FRONT IN EASTERN NORTH CAROLINA SHIFTING
SOUTHWEST DURING SATURDAY EVENING. MOS POP GUIDANCE LOW BUT SREF
AND MODEL QPF SUGGEST SCATTERED SHOWERS AND THUNDERSTORMS AHEAD
AND ALONG FRONT AS AIR MASS MODERATELY UNSTABLE AND MOISTURE
INCREASING...PRECIPITABLE WATER MAY RISE TO AROUND 2 INCHES.
WARM MAX TEMPS STILL POSSIBLE SAT AHEAD OF THE FRONT...WITH
WARMEST TEMPS FAVORING THE CSRA WHERE TEMPS COULD REACH 100 AGAIN.
WITH NAM BEING SLIGHTLY FASTER THAN GFS WITH THE BACK DOOR FRONT...THE
NAM MOS IS SLIGHTLY COOLER THAN THE GFS MOS FOR SAT MAX
TEMP...ESPECIALLY NORTH AND CENTRAL. EVEN IF TEMPS NEAR 100
REACHED AGAIN SAT...GUIDANCE STILL SUGGESTS DEWPOINTS LOW ENOUGH
TO PRECLUDE HEAT INDEX VALUES FROM REACHING OUR HEAT ADVISORY
CRITERIA OF 110F.
FRONT EXPECTED TO SHIFT SW THRU THE FA SAT NIGHT THRU SUN NIGHT.
EXPECT CHANCE POPS NEAR AND JUST AHEAD OF THE FRONT...WITH COOLING
TEMPS ALONG AND NORTH OF IT. SO...POPS SUN AFTERNOON FAVORING THE
CSRA WHERE INSTABILITY/LOW LEVEL CONVERGENCE STRONGER. HIGH TEMPS SUNDAY
SHOULD BE NOTICEABLY LESS BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MODELS IN GOOD AGREEMENT WITH MOVING THE FRONT SOUTH OF THE SAVANNAH
RIVER WITH UPPER LEVEL RIDGE BUILDING IN FOR THE WEEK. WITH COOLER
DRY AIR SETTLING IN WILL BRING SLIGHTLY BELOW NORMAL TEMPS. EXPECT
MAX TEMPS 85 TO 90 EARLY TO MID WEEK RISING BACK INTO THE LOWER 90S
LATER IN THE WEEK. OVERNIGHT MINS WILL BE 65 TO 70 RISING INTO
THE LOWER 70S LATER IN THE WEEK.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
DIURNAL WIDELY SCATTERED CUMULUS AOA 6-7 KFT ACROSS THE REGION
THIS AFTERNOON...BUT THIS WILL BE DIMINISHING THIS EVENING WITH
LOSS OF HEATING. GIVEN FRONTAL BOUNDARY REMAINING WELL NORTH OF
THE AREA...CHANCE FOR CONVECTION TOO LOW TO INCLUDE IN TAFS ATTM.
NORTHWEST TO WEST WINDS 10 KNOTS OR LESS THIS AFTERNOON WILL
DIMINISH AND VEER NORTHERLY OVERNIGHT.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE
NIGHT AND EARLY MORNING FOG SUNDAY AND MONDAY. ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS SATURDAY AND
SUNDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1016 AM EDT FRI AUG 22 2014
.SYNOPSIS...
A STRONG UPPER RIDGE WILL LEAD TO CONTINUED HOT CONDITIONS
TODAY. A BACK DOOR COLD FRONT WILL MOVE SW INTO THE NORTHERN AND
CENTRAL MIDLANDS SATURDAY...AND SHIFT TOWARDS THE CSRA SUNDAY.
THIS WILL LEAD TO A CHANCE OF THUNDERSTORMS ALONG AND AHEAD OF THE
FRONT...WITH TEMPERATURES RETURNING TO MORE NORMAL LEVELS BEHIND
IT. THE FRONT WILL SHIFT TO OUR SOUTH EARLY TO MID NEXT
WEEK...LEADING TO GENERALLY FAIR WEATHER WITH NEAR NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIN HIGH CLOUDS ACROSS THE MIDLANDS LATE THIS MORNING.
TEMPERATURES IN THE MID/UPPER 80S WELL ON THE WAY TO AROUND 100
DEGREES FOR LATER THIS AFTERNOON. MODELS INDICATE SUBSIDENCE
THROUGH LATE AFTERNOON. HAVE DELAYED CHANCE FOR CONVECTION UNTIL
21Z BASED TIMING OF SHORT WAVE INDICATED BY THE RUC AND NAM MODELS
AND ALSO BASES ON HI RES MODELS. OTHERWISE FORECAST STILL ON TRACK.
PREVIOUS DISCUSSION:
UPPER LEVEL RIDGE REMAINS CENTERED OVER THE LOWER MISSISSIPPI
VALLEY. SURFACE TROUGH ACROSS COASTAL CAROLINA. LOW LEVEL
DOWNSLOPE FLOW WILL CONTINUE TODAY. BOUNDARY LAYER AND 850MB
TEMPERATURES SUPPORT AFTERNOON TEMPERATURES NEAR 100 DEGREES. DEW
POINTS MIXING DOWN INTO THE 60S WILL RESULT IN HEAT INDEX VALUES
AROUND 105. NAM MODEL SUGGEST STRONGER INSTABILITY THAN GFS. BUT
EXPECT HIGH LFC AND LIMITED LIFT FOR THUNDERSTORMS. BULK OF
CONVECTION EXPECTED NORTH OF THE REGION AROUND UPPER LEVEL RIDGE.
ISOLATED THUNDERSTORMS FORECAST THIS AFTERNOON AND EARLY EVENING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
MAIN ISSUE FOR SATURDAY AND INTO SUNDAY IS TIMING OF APPROACHING
BACK DOOR FRONT. THINK PRE-FRONTAL TROUGH SETS UP ACROSS SOUTHERN
CWA SATURDAY WITH FRONT IN EASTERN NORTH CAROLINA SHIFTING
SOUTHWEST DURING SATURDAY EVENING. MOS POP GUIDANCE LOW BUT SREF
AND MODEL QPF SUGGEST SCATTERED SHOWERS AND THUNDERSTORMS AHEAD
AND ALONG FRONT AS AIR MASS MODERATELY UNSTABLE AND MOISTURE
INCREASING...PRECIPITABLE WATER MAY RISE TO AROUND 2 INCHES.
WARM MAX TEMPS STILL POSSIBLE SAT AHEAD OF THE FRONT...WITH
WARMEST TEMPS FAVORING THE CSRA WHERE TEMPS COULD REACH 100 AGAIN.
WITH NAM BEING SLIGHTLY FASTER THAN GFS WITH THE BACK DOOR FRONT...THE
NAM MOS IS SLIGHTLY COOLER THAN THE GFS MOS FOR SAT MAX
TEMP...ESPECIALLY NORTH AND CENTRAL. EVEN IF TEMPS NEAR 100
REACHED AGAIN SAT...GUIDANCE STILL SUGGESTS DEWPOINTS LOW ENOUGH
TO PRECLUDE HEAT INDEX VALUES FROM REACHING OUR HEAT ADVISORY
CRITERIA OF 110F.
FRONT EXPECTED TO SHIFT SW THRU THE FA SAT NIGHT THRU SUN NIGHT.
EXPECT CHANCE POPS NEAR AND JUST AHEAD OF THE FRONT...WITH COOLING
TEMPS ALONG AND NORTH OF IT. SO...POPS SUN AFTERNOON FAVORING THE
CSRA WHERE INSTABILITY/LOW LEVEL CONVERGENCE STRONGER. HIGH TEMPS SUNDAY
SHOULD BE NOTICEABLY LESS BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
FRONT TO PUSH TO OUR SOUTH EARLY TO MID NEXT WEEK WITH SURFACE HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD...WITH UPPER RIDGE
ALOFT. SLIGHTLY COOLER AND DRIER AIR BEHIND THE FRONT ALONG WITH
RIDGE ALOFT WILL REDUCE CONVECTIVE CHANCES...TO SLIGHT CHANCE AT
BEST. TEMPS EXPECTED TO BE GENERALLY NEAR NORMAL.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
THIN CIRRUS CLOUDS ACROSS THE TAF SITES IN NORTHWEST FLOW ALOFT.
DIURNAL CUMULUS EXPECTED TO DEVELOP THIS AFTERNOON. GIVEN FRONTAL
BOUNDARY REMAINING WELL NORTH OF THE AREA...CHANCE FOR CONVECTION
TOO LOW TO INCLUDE IN TAFS ATTM. WINDS THROUGH THE PERIOD WILL BE
WESTERLY AT 7 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE
NIGHT AND EARLY MORNING FOG SATURDAY THROUGH MONDAY. ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
149 AM EDT FRI AUG 22 2014
.SYNOPSIS...
A STRONG UPPER RIDGE WILL LEAD TO CONTINUED HOT CONDITIONS
FRIDAY. A BACK DOOR COLD FRONT WILL MOVE SW INTO THE NORTHERN AND
CENTRAL MIDLANDS SATURDAY...AND SHIFT TOWARDS THE CSRA SUNDAY.
THIS WILL LEAD TO A CHANCE OF THUNDERSTORMS ALONG AND AHEAD OF THE
FRONT...WITH TEMPERATURES RETURNING TO MORE NORMAL LEVELS BEHIND
IT. THE FRONT WILL SHIFT TO OUR SOUTH EARLY TO MID NEXT
WEEK...LEADING TO GENERALLY FAIR WEATHER WITH NEAR NORMAL
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPPER RIDGE AND SURFACE HIGH PRESSURE CENTERED OVER THE LOWER
MISSISSIPPI VALLEY/GULF COAST CONTINUE TO DOMINATE THE WEATHER
ACROSS THE MIDLANDS AND CSRA. THIS WILL CONTINUE INTO FRIDAY. 88D
REGIONAL RADAR COMPOSITE SHOWS DECAYING LINE OF SHOWERS MOVING
SOUTHEAST ACROSS CENTRAL/EAST NC. THIS WAS ONCE A PART OF A LARGER
LINE OF SHOWERS AND THUNDERSTORMS THAT BOTH THE HRRR AND WRF
INDICATED WOULD WEAKEN THROUGH THE EVENING HOURS. SATELLITE LOOP
SHOWS SOME DEBRIS CLOUDS FROM THIS CONVECTION THAT WILL BE
SPREADING ACROSS THE REGION OVERNIGHT...ESPECIALLY ALONG THE NC/SC
BORDER. OTHERWISE...SKIES WILL REMAIN MOSTLY CLEAR AND
TEMPERATURES FALLING INTO THE LOWER/MIDDLE 70S BY SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
LITTLE CHANGE FRIDAY. UPPER RIDGE WILL REMAIN CENTERED JUST TO OUR
WEST...WITH SURFACE TROUGH ACROSS THE COASTAL CAROLINAS. THIS AND
A LOW LEVEL DOWNSLOPE FLOW WILL LEAD TO CONTINUED HOT MAX TEMPS.
MODELS CONTINUE TO INDICATE MAX TEMPS NEAR 100 DEGREES AGAIN MOST
AREAS...AND ALSO CONTINUES TO INDICATES DEW POINTS MIXING DOWN
INTO THE 60S ACROSS MOST OF OUR FA TO NEAR 70 SE FA...KEEPING HEAT
INDICES BELOW OUR HEAT ADVISORY CRITERIA OF 110F. ONLY ISOLATED TO
SLIGHT CHANCE DIURNAL TSTMS AT BEST DUE TO BUILDING RIDGE
ALOFT...AND FAIRLY DRY LOW LEVEL AIR LEADING TO HIGH LEVELS OF
FREE CONVECTION/HIGH CONVECTIVE TEMPS.
MAIN ISSUE FOR SATURDAY AND INTO SUNDAY IS TIMING OF APPROACHING
BACK DOOR FRONT. LATEST NAM A LITTLE FASTER THAN GFS. GUIDANCE
BLEND AND SHORT RANGE ENSEMBLE SUGGEST FRONT WITH ASSOCIATED BAND
OF THUNDERSTORMS MOVING INTO THE NORTHERN AND CENTRAL FA SATURDAY
AFTERNOON. CHANCE POPS SHOULD GENERALLY SUFFICE.
WARM MAX TEMPS STILL POSSIBLE SAT AHEAD OF THE FRONT...WITH
WARMEST TEMPS FAVORING THE CSRA WHERE TEMPS COULD REACH 100 AGAIN.
WITH NAM BEING SLIGHTLY FASTER THAN GFS WITH THE BACK DOOR FRONT...THE
NAM MOS IS SLIGHTLY COOLER THAN THE GFS MOS FOR SAT MAX
TEMP...ESPECIALLY NORTH AND CENTRAL. EVEN IF TEMPS NEAR 100
REACHED AGAIN SAT...GUIDANCE STILL SUGGESTS DEWPOINTS LOW ENOUGH
TO PRECLUDE HEAT INDEX VALUES FROM REACHING OUR HEAT ADVISORY
CRITERIA OF 110F.
FRONT EXPECTED TO SHIFT SW THRU THE FA SAT NT THRU SUN NT. EXPECT
CHANCE POPS NEAR AND JUST AHEAD OF THE FRONT...WITH COOLING TEMPS
ALONG AND NORTH OF IT. SO...POPS SUN AFTN FAVORING THE CSRA. HIGH
TEMPS SUNDAY SHOULD BE NOTICEABLY LESS BEHIND THE FRONT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FRONT TO PUSH TO OUR SOUTH EARLY TO MID NEXT WEEK WITH SURFACE HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD...WITH UPPER RIDGE
ALOFT. SLIGHTLY COOLER AND DRIER AIR BEHIND THE FRONT ALONG WITH
RIDGE ALOFT WILL REDUCE CONVECTIVE CHANCES...TO SLIGHT CHANCE AT
BEST. TEMPS EXPECTED TO BE GENERALLY NEAR NORMAL.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH EARLY MORNING MVFR
POSSIBLE AT AGS/OGB.
SOME CONVECTIVE DEBRIS CONTINUES TO CROSS THE REGION WITH MOSTLY
CLEAR SKIES ACROSS THE SOUTHERN MIDLANDS AND CSRA. EXPECT THE
DEBRIS CLOUDS TO LIMIT FOG POTENTIAL...HOWEVER THERE IS ENOUGH
POTENTIAL TO INCLUDE A TEMPO GROUP FOR AGS/OGB BETWEEN 08 AND 12Z
THIS MORNING. FOG WHICH DEVELOPS WILL RAPIDLY ERODE WITH SUNRISE
WITH SOME DIURNAL CUMULUS FORMING THROUGH THE LATE MORNING AND
AFTERNOON HOURS. CHANCES FOR CONVECTION AT THE TAF SITES REMAINS
TOO LOW TO INCLUDE ATTM. WINDS THROUGH THE PERIOD WILL BE WEST TO
NORTHWEST AT 7 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE
NIGHT AND EARLY MORNING FOG SATURDAY THROUGH MONDAY. ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 PM CDT SAT AUG 23 2014
.DISCUSSION...
326 PM CDT
A PERSISTENT UPPER RIDGE THAT HAS BEEN SITTING OVER THE MIDWEST WILL
GRADUALLY FLATTEN AND BE PUSHED TO THE SOUTH AND EAST OVER THE NEXT
FEW DAYS...BUT NOT UNTIL THIS COMING THURSDAY OR FRIDAY WILL IT
AND ITS SURFACE MANIFESTATION BE PUSHED FAR ENOUGH AWAY TO ALLOW A
SURGE OF COOLER AND DRIER AIR INTO THE LOCAL AREA. UNTIL MIDWEEK
THE WARM AND HUMID AIRMASS WILL REMAIN IN PLACE...SUPPORTING
ONGOING CHANCES OF SHOWERS AND THUNDERSTORMS...WITH HEAT INDICIES
ON MONDAY APPROACHING THE LOCAL HEAT ADVISORY CRITERIA OF 105F.
POTENT SHORTWAVES LIFTING THROUGH THE TOP OF THE RIDGE TODAY HAVE
SUPPORTED A BROAD CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN. MODELS
ARE IN REASONABLE AGREEMENT IN SHOWING SIMILAR BUT SOMEWHAT WEAKER
WAVES LIFTING THROUGH AGAIN TOMORROW...THOUGH THE FOCUS IS A BIT
FARTHER WEST. ALSO...MORE PRONOUNCED WARM ADVECTION AROUND THE
850MB LEVEL LOCALLY IS EXPECTED TO INHIBIT CONVECTIVE DEVELOPMENT
COMPARED TO WHAT WE SAW TODAY...AND THE INCREASED CLOUDINESS FROM
THE SHORTWAVES SHOULD ALSO SERVE TO LIMIT THE DEGREE OF AFTERNOON
SURFACE HEATING.
AS A WEAK SURFACE TROUGH APPROACHES SLOWLY FROM THE NORTHWEST...TSRA
CHANCES CREEP BACK UP AGAIN MONDAY AND TUESDAY ALONG WITH...AND
BECAUSE OF...MORE PRONOUNCED LOW LEVEL HEATING WITH SOUTH TO
SOUTHWEST WINDS SUPPORTING BETTER MIXING AND A WEAKER CAP ALOFT.
MONDAY LOOKS TO BE WARMER THAN EITHER SUNDAY OR TUESDAY...AND
AMPLE MOISTURE WILL SUPPORT HEAT INDICIES BETWEEN 100 AND
105...NEAR THE CRITERIA FOR A HEAT ADVISORY. IT IS A BIT EARLY TO
HOIST A HEADLINE BUT THIS WILL CONTINUE TO BE MONITORED.
BY WEDNESDAY THE TROUGH JUST TO OUR NORTHWEST WILL HAVE EVOLVED TO A
WARM FRONT ASSOCIATED WITH A LOW OVER THE PLAINS. THIS LOW THEN
LIFTS ALONG THIS BOUNDARY AND SETTLES OVER THE LOCAL AREA ON
THURSDAY BEFORE CONTINUING OFF TO THE EAST ON FRIDAY. HIGH
TEMPERATURES BOTH WEDNESDAY AND THURSDAY COULD BE TRICKY DEPENDING
ON WHERE THE SURFACE BOUNDARIES SET UP...BUT INCREASED CLOUDINESS
AND ONGOING TSRA CHANCES SHOULD KEEP THOSE DAYS COOLER THAN MONDAY
AND TUESDAY. THE MORE SIGNIFICANT CHANGE OF AIRMASS WILL THEN BE
IN PLACE ACROSS THE ENTIRE AREA BY FRIDAY AND SATURDAY...THOUGH
THE ECMWF IS A BIT SLOWER THAN THE GFS IN PUSHING THIS BOUNDARY
THROUGH.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* VARIABLE WINDS RETURNING TO AN EASTERLY DIRECTION TONIGHT.
* LOW PROBABILITY FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO
SUNDAY MORNING.
* LOW PROBABILITY FOR BRIEF SHRA/TSRA AROUND TERMINALS LATE
TONIGHT.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
RODRIGUEZ
//DISCUSSION...UPDATED 00Z...
QUIETER EARLY THIS EVENING ACROSS THE TERMINALS AS SHOWERS AND
THUNDERSTORMS ARE WELL TO THE EAST IN INDIANA...AND WITH VFR
CONDITIONS IN PLACE. CONDITIONS SHOULD REMAIN QUIET THIS EVENING
WITH DRY CONDITIONS EXPECTED AND WITH LIGHTER VARIABLE WINDS IN
PLACE. AM MONITORING THE POTENTIAL FOR SOME REDEVELOPING SHOWERS
AND THUNDERSTORMS LATE TONIGHT INTO EARLY SUNDAY MORNING AROUND
THE TERMINALS. CONFIDENCE IS LOW WITH COVERAGE...BUT COULD EASILY
SEE AT LEAST SOME ISOLATED TO WIDELY SCATTERED PRECIP TO DEVELOP.
FOCUS SHOULD STAY AWAY FROM THE TERMINALS...BUT WILL NEED TO
MONITOR THE POTENTIAL FOR ANY STRAY PRECIP TO MOVE NEAR THE
TERMINALS. WITH LIGHTER WINDS AND A FAIRLY MOIST ENVIRONMENT IN
PLACE...FOG AND LOW CEILINGS WILL LIKELY DEVELOP TONIGHT. WITH THE
HIGHER CLOUDS IN PLACE...IT WILL LIKELY REMAIN PATCHY.
NONETHELESS...ALL TERMINALS WILL HAVE THE POTENTIAL TO DEVELOP
THIS FOG/LOW CIGS...ESPECIALLY IF THE HIGHER CLOUDS IN PLACE
EXIT. HAVE NOT INCLUDED IFR CEILINGS FOR ORD/MDW...BUT WILL
MONITOR THE NEED TO ADD LATER.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE FOR IFR CIGS/VIS TONIGHT INTO SUNDAY
MORNING.
* LOW CONFIDENCE ON BRIEF SHRA/TSRA LATE TONIGHT.
* MEDIUM HIGH CONFIDENCE WITH LAKE BREEZE SUNDAY.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF TSRA.
TUESDAY...CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
THURSDAY...CHANCE OF TSRA.
FRIDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
904 PM CDT Sat Aug 23 2014
.UPDATE...
ISSUED AT 855 PM CDT SAT AUG 23 2014
Storms have finally pushed southeast of our area early this
evening as the outflow boundary from this morning`s convection
ignited scattered storms across the I70 corridor as it edged
southeast during the afternoon. The air mass from Springfield
south to I70 was characterized by surface base capes of 5500-6000
J/KG but very weak winds aloft, so storms developed quickly but
moved very slowly along the boundary. 00z ILX and DVN soundings
showing the stabilizing effect from the storms that moved across
the area this morning and early this afternoon with capes quite a
bit lower than analyzed across the south with a fairly significant
cap in place.
Looking at the latest HRRR model suggests very little threat for
rain overnight with the axis of the low level jet and 850 mb moisture
convergence further to our west across Iowa into northwest Illinois.
Will remove the slight chances over the east and southeast as the
rain has shifted out of our area. Will keep the threat for fog going
as it appears tonight will be a very similar setup to what occurred
over parts of central and east central Illinois last night. Very
light winds and copious amounts of moisture in the low levels should
lead to patchy fog development after midnight.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Southern flank of morning thunderstorm complex continues to impact
the northeast KILX CWA around Champaign and Danville this afternoon,
with only minimal development noted further southwest along the
trailing outflow boundary. Models have once again handled the
situation poorly, with the NAM/GFS being too aggressive with
convective development and the HRRR keeping system too far north.
Think storms will gradually push into Indiana over the next 3 to 4
hours, followed by only isolated convection across the eastern CWA
early this evening. Once daytime instability wanes, dry conditions
are expected overnight. With clearing skies and light winds, fog
will likely develop late tonight into Sunday morning. Forecast
soundings and numeric guidance both suggest at least some
restriction to visibilities, and based on what happened last night,
think its prudent to carry patchy fog late tonight. Upper ridge
axis will continue to control the weather across central Illinois on
Sunday, providing hot and mainly dry conditions. Some models are
hinting that widely scattered convection may fire along the Indiana
border by afternoon, but think this is a bit overdone. Will only
maintain slight chance PoPs across the far southeast, with dry
weather elsewhere. High temperatures will reach the lower 90s,
resulting in heat index values of 100 to 105 degrees.
&&
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Medium range models are generally in good agreement for the first
few days of next week, then they digress pretty rapidly for two
reasons. First is the difference in solutions involving the speed
and strength of the upper level trough expected to move from the
Rockies to Midwest. This looks like it is being caused by the second
main difference, which is a lot of uncertainty with the speed and
motion of a pending tropical system in the western Atlantic. These
tropical systems tend to back up the west-east progression of
weather systems in the middle U.S. Thus, there is a greater than
normal level of uncertainty with the forecast for Wednesday through
the end of the week.
In the nearer term period for Monday and Tuesday, it appears likely
that the hot and humid conditions will continue. Monday could end up
being one of the hottest days with highs from 93-95 in central IL
and 91-93 in east/southeast IL. This will keep heat index values in
the 105-108 range in much of central and southeast IL, so will keep
the heat advisory going through Monday. Considered extending the
advisory into Tuesday, but will hold off for now since there is some
level of uncertainty as to the amount of increasing cloudiness
during the day, which could keep temps down just a bit.
The movement of a cold front, associated with aforementioned
approaching upper level trough, will really depend on the east coast
tropical system. The most likely scenario, which is not really
handled very well by any model, is that the front will slowly
approach - and may even get hung up in central IL for a day or two.
Thus, will stick with a prolonged period of scattered showers/t-storms
Wednesday into Friday. The cloudiness associated with this rain
potential will keep temperatures down in the 80s, ending the stretch
of hot weather. However, longer term trends indicate the possibility
that we may see a return to very warm conditions for Labor Day
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 600 PM CDT SAT AUG 23 2014
VFR conditions will prevail thru this evening with fog development
the main forecast concern late tonight thru early Sunday morning
with some MVFR and local IFR cigs and vsbys in the 10z-13z time
frame, especially at CMI and BMI. Storms were occurring to the
east and south of the TAF sites late this afternoon and should
remain there into early this evening. A bit concerned about an
outflow boundary stretching from Shelbyville northwest to just
north of SPI. However, have not seen any development in that
location over the past few hours with the newly developed storms
further south. Any fog that does form late tonight should begin
to lift between 13 and 15z with VFR conditions expected for the
remainder of the period. Surface winds will be from and easterly
direction at 4 to 8 kts until sunset and then a light east to
southeast wind is expected after that with speeds of 5 kts or less.
Southeast winds will prevail on Sunday at 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056-
061>063-066>068-071>073.
HEAT ADVISORY from Noon Sunday to 7 PM CDT Monday FOR ILZ036-040-
041.
&&
$$
UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...MILLER
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
711 PM CDT SAT AUG 23 2014
.DISCUSSION...
326 PM CDT
A PERSISTENT UPPER RIDGE THAT HAS BEEN SITTING OVER THE MIDWEST WILL
GRADUALLY FLATTEN AND BE PUSHED TO THE SOUTH AND EAST OVER THE NEXT
FEW DAYS...BUT NOT UNTIL THIS COMING THURSDAY OR FRIDAY WILL IT
AND ITS SURFACE MANIFESTATION BE PUSHED FAR ENOUGH AWAY TO ALLOW A
SURGE OF COOLER AND DRIER AIR INTO THE LOCAL AREA. UNTIL MIDWEEK
THE WARM AND HUMID AIRMASS WILL REMAIN IN PLACE...SUPPORTING
ONGOING CHANCES OF SHOWERS AND THUNDERSTORMS...WITH HEAT INDICIES
ON MONDAY APPROACHING THE LOCAL HEAT ADVISORY CRITERIA OF 105F.
POTENT SHORTWAVES LIFTING THROUGH THE TOP OF THE RIDGE TODAY HAVE
SUPPORTED A BROAD CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN. MODELS
ARE IN REASONABLE AGREEMENT IN SHOWING SIMILAR BUT SOMEWHAT WEAKER
WAVES LIFTING THROUGH AGAIN TOMORROW...THOUGH THE FOCUS IS A BIT
FARTHER WEST. ALSO...MORE PRONOUNCED WARM ADVECTION AROUND THE
850MB LEVEL LOCALLY IS EXPECTED TO INHIBIT CONVECTIVE DEVELOPMENT
COMPARED TO WHAT WE SAW TODAY...AND THE INCREASED CLOUDINESS FROM
THE SHORTWAVES SHOULD ALSO SERVE TO LIMIT THE DEGREE OF AFTERNOON
SURFACE HEATING.
AS A WEAK SURFACE TROUGH APPROACHES SLOWLY FROM THE NORTHWEST...TSRA
CHANCES CREEP BACK UP AGAIN MONDAY AND TUESDAY ALONG WITH...AND
BECAUSE OF...MORE PRONOUNCED LOW LEVEL HEATING WITH SOUTH TO
SOUTHWEST WINDS SUPPORTING BETTER MIXING AND A WEAKER CAP ALOFT.
MONDAY LOOKS TO BE WARMER THAN EITHER SUNDAY OR TUESDAY...AND
AMPLE MOISTURE WILL SUPPORT HEAT INDICIES BETWEEN 100 AND
105...NEAR THE CRITERIA FOR A HEAT ADVISORY. IT IS A BIT EARLY TO
HOIST A HEADLINE BUT THIS WILL CONTINUE TO BE MONITORED.
BY WEDNESDAY THE TROUGH JUST TO OUR NORTHWEST WILL HAVE EVOLVED TO A
WARM FRONT ASSOCIATED WITH A LOW OVER THE PLAINS. THIS LOW THEN
LIFTS ALONG THIS BOUNDARY AND SETTLES OVER THE LOCAL AREA ON
THURSDAY BEFORE CONTINUING OFF TO THE EAST ON FRIDAY. HIGH
TEMPERATURES BOTH WEDNESDAY AND THURSDAY COULD BE TRICKY DEPENDING
ON WHERE THE SURFACE BOUNDARIES SET UP...BUT INCREASED CLOUDINESS
AND ONGOING TSRA CHANCES SHOULD KEEP THOSE DAYS COOLER THAN MONDAY
AND TUESDAY. THE MORE SIGNIFICANT CHANGE OF AIRMASS WILL THEN BE
IN PLACE ACROSS THE ENTIRE AREA BY FRIDAY AND SATURDAY...THOUGH
THE ECMWF IS A BIT SLOWER THAN THE GFS IN PUSHING THIS BOUNDARY
THROUGH.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* VARIABLE WINDS RETURNING TO AN EASTERLY DIRECTION TONIGHT.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LOW PROBABILITY FOR BRIEF SHRA/TSRA AROUND TERMINALS LATE
TONIGHT.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
RODRIGUEZ
//DISCUSSION...UPDATED 00Z...
QUIETER EARLY THIS EVENING ACROSS THE TERMINALS AS SHOWERS AND
THUNDERSTORMS ARE WELL TO THE EAST IN INDIANA...AND WITH VFR
CONDITIONS IN PLACE. CONDITIONS SHOULD REMAIN QUIET THIS EVENING
WITH DRY CONDITIONS EXPECTED AND WITH LIGHTER VARIABLE WINDS IN
PLACE. AM MONITORING THE POTENTIAL FOR SOME REDEVELOPING SHOWERS
AND THUNDERSTORMS LATE TONIGHT INTO EARLY SUNDAY MORNING AROUND
THE TERMINALS. CONFIDENCE IS LOW WITH COVERAGE...BUT COULD EASILY
SEE AT LEAST SOME ISOLATED TO WIDELY SCATTERED PRECIP TO DEVELOP.
FOCUS SHOULD STAY AWAY FROM THE TERMINALS...BUT WILL NEED TO
MONITOR THE POTENTIAL FOR ANY STRAY PRECIP TO MOVE NEAR THE
TERMINALS. WITH LIGHTER WINDS AND A FAIRLY MOIST ENVIRONMENT IN
PLACE...FOG AND LOW CEILINGS WILL LIKELY DEVELOP TONIGHT. WITH THE
HIGHER CLOUDS IN PLACE...IT WILL LIKELY REMAIN PATCHY.
NONETHELESS...ALL TERMINALS WILL HAVE THE POTENTIAL TO DEVELOP
THIS FOG/LOW CIGS...ESPECIALLY IF THE HIGHER CLOUDS IN PLACE
EXIT. HAVE NOT INCLUDED IFR CEILINGS FOR ORD/MDW...BUT WILL
MONITOR THE NEED TO ADD LATER.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE FOR IFR CIGS/VIS TONIGHT INTO SUNDAY
MORNING.
* LOW CONFIDENCE ON BRIEF SHRA/TSRA LATE TONIGHT.
* MEDIUM HIGH CONFIDENCE WITH LAKE BREEZE SUNDAY.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF TSRA.
TUESDAY...CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
THURSDAY...CHANCE OF TSRA.
FRIDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
600 PM CDT Sat Aug 23 2014
.SHORT TERM...(This evening through Sunday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Southern flank of morning thunderstorm complex continues to impact
the northeast KILX CWA around Champaign and Danville this afternoon,
with only minimal development noted further southwest along the
trailing outflow boundary. Models have once again handled the
situation poorly, with the NAM/GFS being too aggressive with
convective development and the HRRR keeping system too far north.
Think storms will gradually push into Indiana over the next 3 to 4
hours, followed by only isolated convection across the eastern CWA
early this evening. Once daytime instability wanes, dry conditions
are expected overnight. With clearing skies and light winds, fog
will likely develop late tonight into Sunday morning. Forecast
soundings and numeric guidance both suggest at least some
restriction to visibilities, and based on what happened last night,
think its prudent to carry patchy fog late tonight. Upper ridge
axis will continue to control the weather across central Illinois on
Sunday, providing hot and mainly dry conditions. Some models are
hinting that widely scattered convection may fire along the Indiana
border by afternoon, but think this is a bit overdone. Will only
maintain slight chance PoPs across the far southeast, with dry
weather elsewhere. High temperatures will reach the lower 90s,
resulting in heat index values of 100 to 105 degrees.
&&
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Medium range models are generally in good agreement for the first
few days of next week, then they digress pretty rapidly for two
reasons. First is the difference in solutions involving the speed
and strength of the upper level trough expected to move from the
Rockies to Midwest. This looks like it is being caused by the second
main difference, which is a lot of uncertainty with the speed and
motion of a pending tropical system in the western Atlantic. These
tropical systems tend to back up the west-east progression of
weather systems in the middle U.S. Thus, there is a greater than
normal level of uncertainty with the forecast for Wednesday through
the end of the week.
In the nearer term period for Monday and Tuesday, it appears likely
that the hot and humid conditions will continue. Monday could end up
being one of the hottest days with highs from 93-95 in central IL
and 91-93 in east/southeast IL. This will keep heat index values in
the 105-108 range in much of central and southeast IL, so will keep
the heat advisory going through Monday. Considered extending the
advisory into Tuesday, but will hold off for now since there is some
level of uncertainty as to the amount of increasing cloudiness
during the day, which could keep temps down just a bit.
The movement of a cold front, associated with aforementioned
approaching upper level trough, will really depend on the east coast
tropical system. The most likely scenario, which is not really
handled very well by any model, is that the front will slowly
approach - and may even get hung up in central IL for a day or two.
Thus, will stick with a prolonged period of scattered showers/t-storms
Wednesday into Friday. The cloudiness associated with this rain
potential will keep temperatures down in the 80s, ending the stretch
of hot weather. However, longer term trends indicate the possibility
that we may see a return to very warm conditions for Labor Day
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 600 PM CDT SAT AUG 23 2014
VFR conditions will prevail thru this evening with fog development
the main forecast concern late tonight thru early Sunday morning
with some MVFR and local IFR cigs and vsbys in the 10z-13z time
frame, especially at CMI and BMI. Storms were occurring to the
east and south of the TAF sites late this afternoon and should
remain there into early this evening. A bit concerned about an
outflow boundary stretching from Shelbyville northwest to just
north of SPI. However, have not seen any development in that
location over the past few hours with the newly developed storms
further south. Any fog that does form late tonight should begin
to lift between 13 and 15z with VFR conditions expected for the
remainder of the period. Surface winds will be from and easterly
direction at 4 to 8 kts until sunset and then a light east to
southeast wind is expected after that with speeds of 5 kts or less.
Southeast winds will prevail on Sunday at 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056-
061>063-066>068-071>073.
HEAT ADVISORY from Noon Sunday to 7 PM CDT Monday FOR ILZ036-040-
041.
&&
$$
SHORT TERM...BARNES
LONG TERM...MILLER
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1118 AM CDT FRI AUG 22 2014
.DISCUSSION...
935 AM CDT
THE MAIN CORRIDOR OF HEAVY RAIN LATE LAST NIGHT INTO EARLY THIS
MORNING HAS SHIFTED INTO CENTRAL IL AND WEAKENED...HOWEVER AN AREA
OF THUNDERSTORM ACTIVITY HAS BUILT FROM EASTERN IA INTO WESTERN
IL AS OF 930 AM. THIS IS ASSOCIATED WITH A SHORT WAVE AND APPEARS
BY RADAR AND SATELLITE ALSO MAS AN MCV WITH IT. SHORT TERM
GUIDANCE VARIES WIDELY ON HOW THIS WILL UNFOLD BUT GIVEN ITS
ORGANIZATION WOULD EXPECT FOR IT TO PROGRESS EASTWARD ALONG AN
AXIS OF CONFLUENT FLOW AT 850-700MB. RAINFALL RATES HAVE TAPERED
IN THE PAST HALF HOUR...BUT STILL IN A VERY MOIST ATMOSPHERE
/PWATS OVER TWO INCHES/ WE ARE SEEING RAINFALL RATES IN EXCESS OF
ONE INCH PER HOUR AT TIMES WITH THIS. PARTS OF LASALLE AND
LIVINGSTON COUNTIES WERE HIT HARD LAST NIGHT INTO EARLY THIS
MORNING...SO THRESHOLDS FOR FLASH FLOOD WARNINGS WILL LIKELY BE
LOW IF THIS AREA WERE TO GET ANY MORE AGGRESSIVE OR SLOW DOWN.
BASED ON CALLS TO EMERGENCY MANAGEMENT AND LAW ENFORCEMENT
PARTNERS...EARLIER FLASH FLOOD WARNINGS WERE TRANSITIONED TO AREAL
FLOOD WARNINGS WHERE MAJOR IMPACTS WERE STILL OCCURRING. THE SAME
MAY BE DONE FOR PART OF LIVINGSTON/LASALLE/GRUNDY COUNTY DEPENDING
ALSO ON HOW EARLIER MENTIONED CONVECTION IS EVOLVING.
THE DENSE FOG ADVISORY FOR LAKE AND MCHENRY COUNTIES WILL BE
ALLOWED TO EXPIRE AT 10 AM AS OBSERVATIONS AND WEBCAMS HAVE SHOWN
IMPROVEMENT.
WILL LIKELY HAVE TO LOWER HIGH TEMPERATURE FORECAST SOME BASED ON
DEGREE OF CLOUD COVER OVER THE AREA. CONTINUED DEW POINTS OF 70 TO
75 WILL KEEP IT FEELING MUGGY.
MTF
//PREV DISCUSSION...
349 AM...FORECAST CONCERNS INCLUDE HEAVY RAIN WITH THUNDERSTORMS
THROUGH SATURDAY NIGHT...IN ADDITION TO TIMING AND LOCATION OF
STORMS. ADDITIONAL CONCERNS AND CHALLENGES INCLUDE TEMPERATURES/
DEWPOINTS AND ASSOCIATED HEAT INDICES THROUGH EARLY NEXT WEEK.
ONE COMPLEX OF THUNDERSTORMS MOVING ACROSS FAR NORTHEAST IL AND
NORTHWEST INDIANA WITH A SECOND COMPLEX MOVING SOUTHEAST ACROSS
THE SOUTHERN CWA. THESE ARE VERY EFFICIENT RAIN PRODUCES WITH
DEWPOINTS IN THE 70S AND PRECIPITABLE WATER VALUES AROUND 2
INCHES. COOP OBSERVER 3SW OF MIDWAY AIRPORT MEASURED 3.60 INCHES
OF RAIN IN JUST 40 MINUTES WITH SEVERAL REPORTS OF FLOODED ROADS
IN THAT AREA. WHILE ADDITIONAL ACTIVITY CONTINUES ACROSS THE
AREA...THE GENERAL TREND IS FOR ALL THIS ACTIVITY TO MOVE
SOUTHEAST THIS MORNING. HOWEVER...ADDITIONAL ACTIVITY OVER
WESTERN IL AND SOUTHERN IOWA MAY CONTINUE MOVING EAST ACROSS THE
SOUTHERN CWA LATER THIS MORNING.
CONVECTIVE TRENDS ARE STILL SOMEWHAT UNCERTAIN OVER THE NEXT 36
HOURS OR SO. IF CURRENT ACTIVITY ACROSS SOUTHERN IA/WESTERN IL
DRIFTS SOUTHEAST...MUCH OF THE DAYLIGHT HOURS COULD END UP RATHER
DRY WITH TONIGHT POSSIBLY BEING MORE ACTIVE AS HINTED AT BY THE
ECMWF. HAVE TRENDED THIS DIRECTION BUT CONFIDENCE IS LOW. WITH
DEWPOINTS REMAINING IN THE LOWER/MID 70S AND PRECIPITABLE WATER
VALUES REMAINING AROUND 2 INCHES...ADDITIONAL TORRENTIAL RAIN WILL
BE POSSIBLE WITH ANY STORMS THAT DEVELOP. IF TRENDS BECOME MORE
CLEAR...ITS POSSIBLE A FLASH FLOOD WATCH MAY BE NEEDED FOR PART OF
THE AREA...BUT GIVEN THE UNCERTAINTY OF WHEN/WHERE ADDITIONAL
HEAVY RAIN WILL OCCUR...NO HEADLINES THIS MORNING.
CONVECTION THEN APPEARS TO SHIFT NORTHEAST DURING THE DAY ON
SATURDAY AS THE UPPER RIDGE BUILDS INTO THE AREA. THUS A DRY
PERIOD IS EXPECTED FROM LATER SATURDAY NIGHT THROUGH SUNDAY NIGHT
AND POSSIBLY INTO MUCH OF THE DAY ON MONDAY. CHANCE POPS THEN
ENTER BACK INTO THE FORECAST THROUGH THURSDAY. MEDIUM RANGE
MODELS ARE IN GOOD AGREEMENT WITH A COLD FRONT MOVING ACROSS THE
AREA MIDWEEK...THOUGH TIMING DIFFERENCES REMAIN. ADDITIONAL HEAVY
RAIN WILL BE POSSIBLE DURING THIS TIME AS WELL.
WHILE SUNDAY MAY END UP BEING COMPLETELY DRY AS THE RIDGE CAPS THE
AREA...IT DOES APPEAR THERE COULD BE A LAKE BREEZE ALONG THE IL
SHORE SUNDAY AFTERNOON. HOW MUCH CONVERGENCE OCCURS IS UNCERTAIN
BUT GIVEN HOW WARM/HUMID CONDITIONS WILL BE SUNDAY AFTERNOON...IF
THIS IS ENOUGH FOR THUNDERSTORMS TO DEVELOP...THERE COULD BE SOME
LOCALLY HEAVY RAIN ACROSS FAR NORTHEAST IL. ADDED SLIGHT CHANCE
POPS DURING THIS TIME TO ACCOUNT FOR THIS POTENTIAL.
DENSE FOG HAS FORMED ACROSS FAR NORTHEAST IL AND MAY SPREAD
SOUTHWEST INTO NORTHWEST IL EARLY THIS MORNING AS RAIN ENDS.
ISSUED A DENSE FOG ADVISORY FOR LAKE/MCHENRY COUNTIES EARLIER THIS
MORNING AND MAY NEED TO EXPAND THAT AS TRENDS EMERGE. DEPENDING ON
PRECIP COVERAGE TONIGHT...AREAS OF FOG POSSIBLY DENSE MAY DEVELOP
AGAIN INTO SATURDAY MORNING.
TEMPERATURES TODAY AND SATURDAY WILL BE DEPENDENT ON CLOUD COVER
AND PRECIP COVERAGE. MADE ONLY SMALL TWEAKS...BASICALLY NO
CHANGES. DID BUMP TEMPS UP A FEW DEGREES ON SUNDAY AND MONDAY WITH
EXPECTED LESS OR NO PRECIP AND MORE SUNSHINE. OVERNIGHT LOWS WILL
LIKELY REMAIN IN THE LOWER 70S MOST AREAS...POSSIBLY MID OR UPPER
70S DOWNTOWN CHICAGO SUNDAY NIGHT/MONDAY MORNING. FORECAST HEAT
INDICES WILL BE NEAR 100 TODAY...RETREAT JUST A LITTLE SATURDAY
AND THEN AGAIN NEAR 100 SUNDAY AND MONDAY. ACROSS THE SOUTHERN
CWA...HEAT INDICES APPROACH THE 105 MARK. IF CURRENT TRENDS
CONTINUE...ITS POSSIBLE PORTIONS OF THE SOUTHERN CWA MAY NEED A
HEAT ADVISORY SUNDAY/MONDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CIGS GRADUALLY LIFTING AND POSSIBLY SCATTERING THROUGH
EARLY-MID AFTERNOON.
* LIGHT SOUTHWEST WINDS TURNING EAST-NORTHEAST EARLY THIS
AFTERNOON. SPEEDS EXPECTED TO BE UNDER 10 KT THROUGH THAT TIME.
* ISOLD SHRA/TSRA POSSIBLE THIS AFTERNOON. MAY DEVELOP WEST OF
TERMINALS AND DRIFT BACK TO THE EAST.
* CHANCES FOR SHRA/TSRA TONIGHT AND SATURDAY MORNING...TIMING
UNCLEAR.
MDB/MTF
//DISCUSSION...UPDATED 12Z...
WEAK LOW PRESSURE EXTENDS FROM SOUTHERN MINNESOTA/NORTHERN IOWA
SOUTHWEST INTO THE SOUTHERN PLAINS. A FRONTAL BOUNDARY EXTENDS
FROM EASTERN IOWA ACROSS NORTHERN ILLINOIS TO NORTHERN INDIANA
THIS MORNING WITH STRONG LOW LEVEL WINDS HELPING DRIVE
THUNDERSTORM ACTIVITY TO THE SOUTH OF THE TERMINALS. SOME SPOTTY
IFR IS IN PROXIMITY TO THE TERMINALS...WITH THE BULK NEAR RFD BUT
THIS SHOULD BE IMPROVING...WITH ORD/MDW/DPA/GYY LIKELY SEEING
LITTLE IF ANY IFR. LIGHT AND SOMEWHAT VARIABLE SOUTH TO SOUTHWEST
WINDS ARE IN PLACE BUT ARE EXPECTED TO TURN EAST AND NORTHEAST
THIS AFTERNOON AS THE FRONT RE-ESTABLISHES ITSELF PERHAPS WITH
THE HELP OF LAKE MICHIGAN. THIS BOUNDARY COUPLED WITH THE VERY
HUMID AIRMASS MAY TRIGGER ISOLD-SCT SHRA/TSRA THIS AFTERNOON
INLAND OF THE LAKE WHICH WOULD THEN DRIFT BACK TOWARDS THE LAKE
AFTER DEVELOPMENT. HAVE INCLUDED VCTS MENTION AT ORD/MDW/RFD/DPA
WITH DECENT CONFIDENCE THAT ACTIVITY WILL OCCUR BUT WITH QUESTION
MARKS SURROUNDING THE EXTENT.
WINDS WILL DIMINISH THIS EVENING/TONIGHT WHICH MAY ALLOW SOME
SHALLOW DENSE FOG OR MORE WIDESPREAD MVFR TYPE FOG. TSRA CHANCES
REMAIN A CHALLENGE BUT HAVE PRETTY LOW CONFIDENCE IN WHEN THE BEST
OPPORTUNITY WILL BE THIS EVENING THROUGH SATURDAY. WITH THE
FRONTAL BOUNDARY EXPECTED TO BE IN THE REGION IT WOULD LIKELY
SERVE AS A TRIGGER BUT IT MAY BE SOUTH OF THE AREA TONIGHT. UPPER
RIDGING WILL BUILD IN SATURDAY WHICH WOULD BRING ANOTHER PUSH OF
WARM AIR AND COUPLED WITH THE BOUNDARY WOULD PROBABLY DRIVE MORE
TSRA DEVELOPMENT WHICH MAY BE FAVORED SATURDAY MORNING. WILL LEAVE
THE TAF DRY BEYOND THIS AFTERNOON GIVEN THE UNCERTAINTY BUT HAVE
DECENT CONFIDENCE THAT TSRA WILL OCCUR AT SOME POINT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW IN HOW LONG MVFR CIGS WILL PERSIST.
* HIGH IN SW WINDS BECOMING NORTHEAST THIS AFTERNOON. MEDIUM IN
SPEEDS UNDER 10 KT. LOW IN TIMING OF SHIFT TO NORTHEAST.
* MEDIUM THAT THERE WILL BE SOME ISOLD SHRA/TSRA DEVELOPMENT THIS
AFTERNOON. LOW IF THEY WILL OCCUR AT TERMINALS.
* LOW IN TIMING OF BEST SHRA/TSRA CHANCES THIS EVENING THROUGH
SATURDAY MORNING.
MDB/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
* SATURDAY NIGHT THROUGH THURSDAY...PERIODIC CHANCES FOR
TSRA/SHRA WITH OCNL MVFR CIGS/VIS.
MDB
&&
.MARINE...
349 AM CDT
AN ELONGATED AREA OF LOW PRESSURE STRETCHES FROM SOUTHERN MINNESOTA
INTO THE SOUTHERN PLAINS WITH A WEAK WARM FRONTAL BOUNDARY
STRETCHING FROM NORTHERN INDIANA BACK INTO CENTRAL/NORTHERN IOWA.
THIS FRONT WILL MOVE LITTLE INTO SATURDAY. MORNING STORMS HAVE
CAUSED WINDS TO BE A BIT CHAOTIC ACROSS THE FAR SOUTHERN PART OF THE
LAKE WHERE SOUTH TO SOUTHEAST WINDS WILL TURN MORE EAST AND
NORTHEAST INTO THE AFTERNOON. LOW PRESSURE WILL ORGANIZE ACROSS THE
CENTRAL AND NORTHERN PLAINS LATER SATURDAY AND MOVE TO WESTERN
ONTARIO SUNDAY ALLOWING WINDS TO TURN SOUTHERLY AND INCREASE IN
SPEED TOWARD MONDAY. THE LOW WILL THEN TRACK TO THE NORTHEAST EARLY
NEXT WEEK DRAGGING A FRONTAL BOUNDARY SOUTHWARD WHICH MAY STALL OUT
SOMEWHERE ACROSS THE LAKE ALLOWING FOR VARIABLE WINDS. ANOTHER LOW
IS EXPECTED TO LIFT NORTHEAST MID WEEK BRINGING A STRONGER COLD
FRONT ACROSS THE LAKE WHICH WOULD BRING A SHIFT TO NORTH AND
NORTHWEST WINDS. STILL EARLY FOR DETAILS BUT THIS SCENARIO WOULD
BRING A PERIOD OF STRONGER WIND SPEEDS THANKS TO COLD
ADVECTION...NOT UNLIKE SIMILAR COLD FRONTAL PASSAGES WE HAVE SEEN
THE PAST FEW WEEKS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1038 AM CDT Fri Aug 22 2014
.UPDATE...
ISSUED AT 1038 AM CDT FRI AUG 22 2014
Large cluster of thunderstorms that developed along an outflow
boundary late last night continues to diminish as it pushes
eastward across central Illinois this morning. 1530z radar imagery
shows showers with a few embedded thunderstorms along/north of a
Beardstown...to Decatur...to Paris line. High-res models suggest a
continued weakening trend, with little or no precip remaining by
mid-afternoon. Have adjusted PoPs to go categorical along/north of
I-72 for the next couple of hours, followed by a decrease to just
slight chance this afternoon. Have also lowered high temperatures
by a few degrees across the central and northern zones where
widespread clouds/rain have kept readings cooler than previously
expected. Visible satellite imagery shows plenty of breaks
developing upstream across Iowa, so have only dropped highs into
the upper 80s. Further south where the rain has not occurred this
morning, have maintained highs in the lower 90s.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 325 AM CDT FRI AUG 22 2014
07z/2am surface analysis shows a stationary front extending from
west to east across northern Illinois. A 35kt LLJ has helped trigger
a line of convection just south of that front. Those storms will
affect our northern counties early this morning, with locally heavy
rainfall rates possible. Areas near Midway airport last night picked
up 3" in 30 minutes. There most likely will be a break in the
rainfall for at least a few hours later this morning and early this
afternoon, before the next shortwave over Iowa works its way into
IL. Precipitable water values up near 2" will continue through the
day, so any convection that redevelops this afternoon into evening
will have the potential to produce very heavy rainfall. Coverage may
not be too extensive during the day, so slight chance and low chance
PoPs were used for areas north of I-72 after 7 am.
The HRRR/NAM/GFS/ECMWF all show an enhanced opportunity for storms
either later this afternoon or this evening as an MCS develops to
our west and rolls across N IL. With timing still in question, we
did not ramp up to likely PoPs in any one area even this evening and
overnight. The main theme does seem to be that the northern half of
the KILX CWA will be the main target area for storms over the next
24-36 hours.
High temps today will once again climb into the upper 80s to low
90s, with dewpoints already in the mid 70s and likely to climb into
the upper 70s in some areas. Heat index readings will likely climb
to around 105 in southern areas. We can not rule out the possible
need to expand the heat advisory northward. Precip and cloud cover
across the north should keep their heat index readings below
advisory levels in general.
&&
.LONG TERM...(Saturday through Thursday)
ISSUED AT 325 AM CDT FRI AUG 22 2014
Main issue through the extended remains the extreme heat for this
time of year through the weekend and into the first portion of next
week. Models still having issues with the ultimate breaking down of
the ridge, resulting in a potential extension to the heat wave
should the trend continue. Hot daytime highs into the 90s and
dewpoints into the mid 70s resulting in heat indices over 100F for
several days on end. Scattered chances exist as long as the
boundary remains close to the FA...and will be the only chance for
brief cool downs. But as the high builds into the region, the
general subsidence will be hard to overcome, so the forecast for
Saturday night through Sunday night is dry for now...with some
slight chances coming back for Monday...but the models struggling
with the solutions in the mid range with the timing of a vigorous
wave to erode the ridge. GFS still far more aggressive, amplified,
and fast with the passage of the upper trof/sfc front Tues night
into Wednesday. ECMWF starting to close the gap and has abandoned
the closed low of 24 hrs ago... but is still signif weaker,
resulting in a developing baroclinic zone at the sfc as the wave
fizzles in parallel flow and provides a focus for a longer duration
potential for precip. Model blends now through the mid/end of next
week results in more widespread chances.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 652 AM CDT FRI AUG 22 2014
A nocturnal LLJ has helped fuel an east-west line of storms across
north-central IL. The storms with heavy rainfall will affect
mainly PIA, BMI and CMI early this morning, bringing MVFR vis and
ceilings. BMI has dropped to IFR cloud height, which could linger
through 15z before lifting to MVFR. A break in the storms is
indicated for the terminal sites for late morning into afternoon
in the HRRR and RAP model output. Additional storm chances are
indicated for later this afternoon and evening for the northern
TAF sites of PIA, BMI and CMI. We kept precip our of DEC and SPI
for now, but trends are for storms to get quite close even this
morning. Will monitor closely for changes to the dry forecast for
SPI/DEC.
Winds will generally remain S-SW in the synoptic flow across our
area, south of the warm front. Local northerly winds have
developed for the northern terminals where the storms have
produced an outflow boundary moving south. The outflow could even
reach SPI and DEC, but wind speeds by then should be 10kt or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056-
061>063-066>068-071>073.
&&
$$
UPDATE...BARNES
SHORT TERM...SHIMON
LONG TERM...HJS
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
654 AM CDT FRI AUG 22 2014
.DISCUSSION...
349 AM...FORECAST CONCERNS INCLUDE HEAVY RAIN WITH THUNDERSTORMS
THROUGH SATURDAY NIGHT...IN ADDITION TO TIMING AND LOCATION OF
STORMS. ADDITIONAL CONCERNS AND CHALLENGES INCLUDE TEMPERATURES/
DEWPOINTS AND ASSOCIATED HEAT INDICES THROUGH EARLY NEXT WEEK.
ONE COMPLEX OF THUNDERSTORMS MOVING ACROSS FAR NORTHEAST IL AND
NORTHWEST INDIANA WITH A SECOND COMPLEX MOVING SOUTHEAST ACROSS
THE SOUTHERN CWA. THESE ARE VERY EFFICIENT RAIN PRODUCES WITH
DEWPOINTS IN THE 70S AND PRECIPITABLE WATER VALUES AROUND 2
INCHES. COOP OBSERVER 3SW OF MIDWAY AIRPORT MEASURED 3.60 INCHES
OF RAIN IN JUST 40 MINUTES WITH SEVERAL REPORTS OF FLOODED ROADS
IN THAT AREA. WHILE ADDITIONAL ACTIVITY CONTINUES ACROSS THE
AREA...THE GENERAL TREND IS FOR ALL THIS ACTIVITY TO MOVE
SOUTHEAST THIS MORNING. HOWEVER...ADDITIONAL ACTIVITY OVER
WESTERN IL AND SOUTHERN IOWA MAY CONTINUE MOVING EAST ACROSS THE
SOUTHERN CWA LATER THIS MORNING.
CONVECTIVE TRENDS ARE STILL SOMEWHAT UNCERTAIN OVER THE NEXT 36
HOURS OR SO. IF CURRENT ACTIVITY ACROSS SOUTHERN IA/WESTERN IL
DRIFTS SOUTHEAST...MUCH OF THE DAYLIGHT HOURS COULD END UP RATHER
DRY WITH TONIGHT POSSIBLY BEING MORE ACTIVE AS HINTED AT BY THE
ECMWF. HAVE TRENDED THIS DIRECTION BUT CONFIDENCE IS LOW. WITH
DEWPOINTS REMAINING IN THE LOWER/MID 70S AND PRECIPITABLE WATER
VALUES REMAINING AROUND 2 INCHES...ADDITIONAL TORRENTIAL RAIN WILL
BE POSSIBLE WITH ANY STORMS THAT DEVELOP. IF TRENDS BECOME MORE
CLEAR...ITS POSSIBLE A FLASH FLOOD WATCH MAY BE NEEDED FOR PART OF
THE AREA...BUT GIVEN THE UNCERTAINTY OF WHEN/WHERE ADDITIONAL
HEAVY RAIN WILL OCCUR...NO HEADLINES THIS MORNING.
CONVECTION THEN APPEARS TO SHIFT NORTHEAST DURING THE DAY ON
SATURDAY AS THE UPPER RIDGE BUILDS INTO THE AREA. THUS A DRY
PERIOD IS EXPECTED FROM LATER SATURDAY NIGHT THROUGH SUNDAY NIGHT
AND POSSIBLY INTO MUCH OF THE DAY ON MONDAY. CHANCE POPS THEN
ENTER BACK INTO THE FORECAST THROUGH THURSDAY. MEDIUM RANGE
MODELS ARE IN GOOD AGREEMENT WITH A COLD FRONT MOVING ACROSS THE
AREA MIDWEEK...THOUGH TIMING DIFFERENCES REMAIN. ADDITIONAL HEAVY
RAIN WILL BE POSSIBLE DURING THIS TIME AS WELL.
WHILE SUNDAY MAY END UP BEING COMPLETELY DRY AS THE RIDGE CAPS THE
AREA...IT DOES APPEAR THERE COULD BE A LAKE BREEZE ALONG THE IL
SHORE SUNDAY AFTERNOON. HOW MUCH CONVERGENCE OCCURS IS UNCERTAIN
BUT GIVEN HOW WARM/HUMID CONDITIONS WILL BE SUNDAY AFTERNOON...IF
THIS IS ENOUGH FOR THUNDERSTORMS TO DEVELOP...THERE COULD BE SOME
LOCALLY HEAVY RAIN ACROSS FAR NORTHEAST IL. ADDED SLIGHT CHANCE
POPS DURING THIS TIME TO ACCOUNT FOR THIS POTENTIAL.
DENSE FOG HAS FORMED ACROSS FAR NORTHEAST IL AND MAY SPREAD
SOUTHWEST INTO NORTHWEST IL EARLY THIS MORNING AS RAIN ENDS.
ISSUED A DENSE FOG ADVISORY FOR LAKE/MCHENRY COUNTIES EARLIER THIS
MORNING AND MAY NEED TO EXPAND THAT AS TRENDS EMERGE. DEPENDING ON
PRECIP COVERAGE TONIGHT...AREAS OF FOG POSSIBLY DENSE MAY DEVELOP
AGAIN INTO SATURDAY MORNING.
TEMPERATURES TODAY AND SATURDAY WILL BE DEPENDENT ON CLOUD COVER
AND PRECIP COVERAGE. MADE ONLY SMALL TWEAKS...BASICALLY NO
CHANGES. DID BUMP TEMPS UP A FEW DEGREES ON SUNDAY AND MONDAY WITH
EXPECTED LESS OR NO PRECIP AND MORE SUNSHINE. OVERNIGHT LOWS WILL
LIKELY REMAIN IN THE LOWER 70S MOST AREAS...POSSIBLY MID OR UPPER
70S DOWNTOWN CHICAGO SUNDAY NIGHT/MONDAY MORNING. FORECAST HEAT
INDICES WILL BE NEAR 100 TODAY...RETREAT JUST A LITTLE SATURDAY
AND THEN AGAIN NEAR 100 SUNDAY AND MONDAY. ACROSS THE SOUTHERN
CWA...HEAT INDICES APPROACH THE 105 MARK. IF CURRENT TRENDS
CONTINUE...ITS POSSIBLE PORTIONS OF THE SOUTHERN CWA MAY NEED A
HEAT ADVISORY SUNDAY/MONDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* BRIEF IFR CIG POSSIBLE NEXT 1-2 HRS.
* VARIABLE SW WINDS TURNING NORTHEAST EARLY THIS AFTERNOON. SPEEDS
EXPECTED TO BE UNDER 10 KT.
* ISOLD-SCT SHRA/TSRA POSSIBLE MID/LATE AFTERNOON. MAY DEVELOP
WEST OF TERMINALS AND DRIFT BACK TO THE EAST.
* CHANCES FOR SHRA/TSRA TONIGHT AND SATURDAY MORNING...TIMING
UNCLEAR.
MDB
//DISCUSSION...UPDATED 12Z...
WEAK LOW PRESSURE EXTENDS FROM SOUTHERN MINNESOTA/NORTHERN IOWA
SOUTHWEST INTO THE SOUTHERN PLAINS. A FRONTAL BOUNDARY EXTENDS
FROM EASTERN IOWA ACROSS NORTHERN ILLINOIS TO NORTHERN INDIANA
THIS MORNING WITH STRONG LOW LEVEL WINDS HELPING DRIVE
THUNDERSTORM ACTIVITY TO THE SOUTH OF THE TERMINALS. SOME SPOTTY
IFR IS IN PROXIMITY TO THE TERMINALS...WITH THE BULK NEAR RFD BUT
THIS SHOULD BE IMPROVING...WITH ORD/MDW/DPA/GYY LIKELY SEEING
LITTLE IF ANY IFR. LIGHT AND SOMEWHAT VARIABLE SOUTH TO SOUTHWEST
WINDS ARE IN PLACE BUT ARE EXPECTED TO TURN EAST AND NORTHEAST
THIS AFTERNOON AS THE FRONT RE-ESTABLISHES ITSELF PERHAPS WITH
THE HELP OF LAKE MICHIGAN. THIS BOUNDARY COUPLED WITH THE VERY
HUMID AIRMASS MAY TRIGGER ISOLD-SCT SHRA/TSRA THIS AFTERNOON
INLAND OF THE LAKE WHICH WOULD THEN DRIFT BACK TOWARDS THE LAKE
AFTER DEVELOPMENT. HAVE INCLUDED VCTS MENTION AT ORD/MDW/RFD/DPA
WITH DECENT CONFIDENCE THAT ACTIVITY WILL OCCUR BUT WITH QUESTION
MARKS SURROUNDING THE EXTENT.
WINDS WILL DIMINISH THIS EVENING/TONIGHT WHICH MAY ALLOW SOME
SHALLOW DENSE FOG OR MORE WIDESPREAD MVFR TYPE FOG. TSRA CHANCES
REMAIN A CHALLENGE BUT HAVE PRETTY LOW CONFIDENCE IN WHEN THE BEST
OPPORTUNITY WILL BE THIS EVENING THROUGH SATURDAY. WITH THE
FRONTAL BOUNDARY EXPECTED TO BE IN THE REGION IT WOULD LIKELY
SERVE AS A TRIGGER BUT IT MAY BE SOUTH OF THE AREA TONIGHT. UPPER
RIDGING WILL BUILD IN SATURDAY WHICH WOULD BRING ANOTHER PUSH OF
WARM AIR AND COUPLED WITH THE BOUNDARY WOULD PROBABLY DRIVE MORE
TSRA DEVELOPMENT WHICH MAY BE FAVORED SATURDAY MORNING. WILL LEAVE
THE TAF DRY BEYOND THIS AFTERNOON GIVEN THE UNCERTAINTY BUT HAVE
DECENT CONFIDENCE THAT TSRA WILL OCCUR AT SOME POINT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE THAT ANY IFR WOULD BE BRIEF.
* HIGH CONFIDENCE IN LIGHT SW WINDS BECOMING NORTHEAST THIS
AFTERNOON. MEDIUM-HIGH CONFIDENCE IN SPEEDS UNDER 10 KT. MEDIUM
CONFIDENCE IN TIMING OF SHIFT TO NORTHEAST.
* MEDIUM CONFIDENCE THAT THERE WILL BE SOME ISOLD/SCT SHRA/TSRA
DEVELOPMENT THIS AFTERNOON.
* LOW CONFIDENCE IN TIMING OF BEST SHRA/TSRA CHANCES THIS EVENING
THROUGH SATURDAY MORNING BUT MEDIUM CONFIDENCE THAT ADDITIONAL
ACTIVITY WILL OCCUR DURING THIS TIME.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
* SATURDAY NIGHT THROUGH THURSDAY...PERIODIC CHANCES FOR
TSRA/SHRA WITH OCNL MVFR CIGS/VIS.
MDB
&&
.MARINE...
349 AM CDT
AN ELONGATED AREA OF LOW PRESSURE STRETCHES FROM SOUTHERN MINNESOTA
INTO THE SOUTHERN PLAINS WITH A WEAK WARM FRONTAL BOUNDARY
STRETCHING FROM NORTHERN INDIANA BACK INTO CENTRAL/NORTHERN IOWA.
THIS FRONT WILL MOVE LITTLE INTO SATURDAY. MORNING STORMS HAVE
CAUSED WINDS TO BE A BIT CHAOTIC ACROSS THE FAR SOUTHERN PART OF THE
LAKE WHERE SOUTH TO SOUTHEAST WINDS WILL TURN MORE EAST AND
NORTHEAST INTO THE AFTERNOON. LOW PRESSURE WILL ORGANIZE ACROSS THE
CENTRAL AND NORTHERN PLAINS LATER SATURDAY AND MOVE TO WESTERN
ONTARIO SUNDAY ALLOWING WINDS TO TURN SOUTHERLY AND INCREASE IN
SPEED TOWARD MONDAY. THE LOW WILL THEN TRACK TO THE NORTHEAST EARLY
NEXT WEEK DRAGGING A FRONTAL BOUNDARY SOUTHWARD WHICH MAY STALL OUT
SOMEWHERE ACROSS THE LAKE ALLOWING FOR VARIABLE WINDS. ANOTHER LOW
IS EXPECTED TO LIFT NORTHEAST MID WEEK BRINGING A STRONGER COLD
FRONT ACROSS THE LAKE WHICH WOULD BRING A SHIFT TO NORTH AND
NORTHWEST WINDS. STILL EARLY FOR DETAILS BUT THIS SCENARIO WOULD
BRING A PERIOD OF STRONGER WIND SPEEDS THANKS TO COLD
ADVECTION...NOT UNLIKE SIMILAR COLD FRONTAL PASSAGES WE HAVE SEEN
THE PAST FEW WEEKS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ005-ILZ006 UNTIL 10 AM FRIDAY.
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
652 AM CDT Fri Aug 22 2014
.SHORT TERM...(Today and tonight)
ISSUED AT 325 AM CDT FRI AUG 22 2014
07z/2am surface analysis shows a stationary front extending from
west to east across northern Illinois. A 35kt LLJ has helped trigger
a line of convection just south of that front. Those storms will
affect our northern counties early this morning, with locally heavy
rainfall rates possible. Areas near Midway airport last night picked
up 3" in 30 minutes. There most likely will be a break in the
rainfall for at least a few hours later this morning and early this
afternoon, before the next shortwave over Iowa works its way into
IL. Precipitable water values up near 2" will continue through the
day, so any convection that redevelops this afternoon into evening
will have the potential to produce very heavy rainfall. Coverage may
not be too extensive during the day, so slight chance and low chance
PoPs were used for areas north of I-72 after 7 am.
The HRRR/NAM/GFS/ECMWF all show an enhanced opportunity for storms
either later this afternoon or this evening as an MCS develops to
our west and rolls across N IL. With timing still in question, we
did not ramp up to likely PoPs in any one area even this evening and
overnight. The main theme does seem to be that the northern half of
the KILX CWA will be the main target area for storms over the next
24-36 hours.
High temps today will once again climb into the upper 80s to low
90s, with dewpoints already in the mid 70s and likely to climb into
the upper 70s in some areas. Heat index readings will likely climb
to around 105 in southern areas. We can not rule out the possible
need to expand the heat advisory northward. Precip and cloud cover
across the north should keep their heat index readings below
advisory levels in general.
&&
.LONG TERM...(Saturday through Thursday)
ISSUED AT 325 AM CDT FRI AUG 22 2014
Main issue through the extended remains the extreme heat for this
time of year through the weekend and into the first portion of next
week. Models still having issues with the ultimate breaking down of
the ridge, resulting in a potential extension to the heat wave
should the trend continue. Hot daytime highs into the 90s and
dewpoints into the mid 70s resulting in heat indices over 100F for
several days on end. Scattered chances exist as long as the
boundary remains close to the FA...and will be the only chance for
brief cool downs. But as the high builds into the region, the
general subsidence will be hard to overcome, so the forecast for
Saturday night through Sunday night is dry for now...with some
slight chances coming back for Monday...but the models struggling
with the solutions in the mid range with the timing of a vigorous
wave to erode the ridge. GFS still far more aggressive, amplified,
and fast with the passage of the upper trof/sfc front Tues night
into Wednesday. ECMWF starting to close the gap and has abandoned
the closed low of 24 hrs ago... but is still signif weaker,
resulting in a developing baroclinic zone at the sfc as the wave
fizzles in parallel flow and provides a focus for a longer duration
potential for precip. Model blends now through the mid/end of next
week results in more widespread chances.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 652 AM CDT FRI AUG 22 2014
A nocturnal LLJ has helped fuel an east-west line of storms across
north-central IL. The storms with heavy rainfall will affect
mainly PIA, BMI and CMI early this morning, bringing MVFR vis and
ceilings. BMI has dropped to IFR cloud height, which could linger
through 15z before lifting to MVFR. A break in the storms is
indicated for the terminal sites for late morning into afternoon
in the HRRR and RAP model output. Additional storm chances are
indicated for later this afternoon and evening for the northern
TAF sites of PIA, BMI and CMI. We kept precip our of DEC and SPI
for now, but trends are for storms to get quite close even this
morning. Will monitor closely for changes to the dry forecast for
SPI/DEC.
Winds will generally remain S-SW in the synoptic flow across our
area, south of the warm front. Local northerly winds have
developed for the northern terminals where the storms have
produced an outflow boundary moving south. The outflow could even
reach SPI and DEC, but wind speeds by then should be 10kt or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY from 1 PM this afternoon to 7 PM CDT Monday FOR
ILZ042-047>054-056-061>063-066>068-071>073.
&&
$$
SHORT TERM...SHIMON
LONG TERM...HJS
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1028 AM EDT FRI AUG 22 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 235 AM EDT FRI AUG 22 2014
AN ACTIVE AND WARM WEATHER PATTERN WILL REMAIN IN PLACE THROUGH
THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY. THIS WILL ALLOW VERY WARM AND HUMID AIR
TO PUSH INTO THE OHIO VALLEY. MEANWHILE...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES ARE EXPECTED TO PUSH INTO NORTHERN AND
CENTRAL INDIANA ALONG A LINGERING FRONTAL BOUNDARY. THIS WILL
RESULT IN DAILY CHANCES FOR SHOWERS OR STORMS THROUGH THE WEEKEND.
NEXT WEEK ANOTHER FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES
FOR RAIN AND WILL EVENTUALLY BRING A RETURN TO NEAR AVERAGE
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
SURFACE ANALYSIS EARLY THIS MORNING SHOWS A WARM FRONTAL BOUNDARY
IN PLACE ACROSS NORTHERN AND CENTRAL INDIANA...STRETCHING FROM
NEAR CHICAGO TO MUNCIE AND WINCHESTER. RADAR CONTINUES TO SHOW
SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT ALONG THE FRONT.
ALOFT A RIDGE OF HIGH PRESSURE WAS IN PLACE OVER THE LOWER
MISSISSIPPI RIVER VALLEY...ALLOWING FOR UPPER LEVEL WEATHER
DISTURBANCES TO RIDE THE RIDGE AND SPILL ACROSS THE WARM FRONT
ACROSS THE NORTHERN AND CENTRAL INDIANA...ALL THE WHILE BEING A
TRIGGER FOR TSRA. MEANWHILE...A VERY WARM AND MOIST AIR MASS
REMAINS IN PLACE ACROSS CENTRAL INDIANA WITH DEW POINTS IN THE
UPPER 60S AND LOWER 70S. SKIES WERE CLOUDY...FILLED WITH DEBRIS
FROM EARLIER CONVECTION.
MAIN FORECAST CHALLENGE TODAY WILL BE POPS.
GFS AND NAM AGREE TO AN AMPLIFICATION OF THE UPPER RIDGE ACROSS THE
MISSISSIPPI RIVER VALLEY TODAY...HOWEVER THIS WILL STILL RESULT
IN MORE OF THE SAME AS THE UPPER FLOW WILL BE POISED TO SPILL
ALONG THE LINGERING FRONTAL BOUNDARY ACROSS CENTRAL AND NORTHERN
INDIANA. FORECAST SOUNDINGS ACROSS THE AREA TODAY CONTINUE TO SHOW
PLENTY OF MOISTURE AVAILABLE WITH OVER 2 INCHES OF PRECIPITABLE
WATER. FORECAST SOUNDINGS ALSO IMPLY CONDITIONAL INSTABILITY WITH
CAPE IN EXCESS OF 200 J/KG...HOWEVER CONVECTIVE TEMPS ARE IN THE
LOWER 90S...WHICH SEEM A LITTLE HIGH. CONFIDENCE REMAINS LOW IN
ANY SPECIFIC TIMING FOR TSRA TODAY AS GFS AND NAM BOTH FAIL TO
SUGGEST ANY SPECIFIC ORGANIZED WAVE TO PASS ALOFT. HRRR DOES
SUGGEST CONVECTION ACROSS THE NORTHERN PARTS OF THE FORECAST AREA
THIS MORNING...AN GIVEN THE LATEST RADAR TRENDS WILL STEER TOWARD
THIS SOLUTION. HOWEVER GIVEN THE MOIST AIR MASS IN PLACE ALONG
WITH THE LINGERING FRONTAL BOUNDARY...WILL KEEP POPS IN PLACE
THROUGH THE DAY.
AS FOR TEMPS...WITH CLOUDS AND POSSIBLE RAIN TODAY...WILL TREND
TOWARD PERSISTENCE...WHICH SHOULD BE COOLER THAN MAVMOS. WARMER
TEMPS WILL BE FOUND ACROSS THE SW FORECAST AREA WHERE POPS CHANCES
AND CLOUDS WILL BE MUCH LESS...DUE TO PROXIMITY TO THE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
GFS AND NAM SUGGEST LITTLE OVERALL CHANGE IN THE ONGOING PATTERN
TONIGHT AND SATURDAY. THE UPPER RIDGE TO THE WEST CONTINUES TO ALLOW
WEAK UPPER DISTURBANCES TO SPILL SOUTHEAST INTO INDIANA. THE
WARM...HUMID AND CONDITIONALLY UNSTABLE AIRMASS REMAINS IN PLACE.
FORECAST SOUNDINGS REMAIN DEEPLY SATURATED WITH VERY HIGH
PRECIPITABLE WATER VALUES. LINGERING SURFACE BOUNDARY REMAINS IN
PLACE ALSO. THUS WILL RAISE POPS TONIGHT AND ON SATURDAY AS THESE
FEATURES CONTINUE TO REMAIN IN PLACE. GIVEN THE EXPECTED CLOUDS AND
RAIN...WILL CONTINUE TO TREND OF LEANING WARMER THAN MAVMOS ON LOWS
AND COOLER ON HIGHS.
ON SATURDAY NIGHT THROUGH MONDAY...THE UPPER RIDGE AXIS BEGINS TO
DRIFT EAST...WHICH BEGINS TO ALLOW DRIER AIR TO ENTER THE FORECAST
COLUMN. THE UPPER STEERING FLOW BEGINS TO SHIFT ANY RIDGE RIDING
SHORT WAVES WELL EAST OF INDIANA. WITH ET DRIER AIR ARRIVING
PRECIPITABLE WATER IN THE FORECAST SOUNDINGS FALLS TO LESS THAN
1.75 IN. ALSO 700MB TEMPS RISE TOWARD 10C...OFTEN A KEY CAPPING
TEMPERATURE. THUS WILL TREND POPS AT OR BELOW MAVMOS ON SUNDAY
THROUGH MONDAY. AS FOR TEMPS...WILL TREND HIGHS AND LOWS WARMER
THAN MAVMOS GIVEN THE VERY WARM AIR MASS THAT IS EXPECTED ACROSS
THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH NEXT THURSDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
ENSEMBLES SUGGEST UPPER RIDGE INITIALLY OVER THE AREA AT THE
BEGINNING OF THE PERIOD WILL EVENTUALLY GET SUPPRESSED BACK TO THE
SOUTH AS AN UPPER TROUGH MOVES INTO THE NORTHERN MIDWEST OR GREAT
LAKES BY THE MIDDLE OF NEXT WEEK.
ENSEMBLES SUGGEST PRECIPITATION POTENTIAL WILL MOVE BACK INTO THE
AREA STARTING NEXT TUESDAY AS UPPER RIDGE BEGINS TO FLATTEN
OUT...WITH THE BEST CHANCES NEXT WEDNESDAY AND THURSDAY AS A FRONTAL
SYSTEM ASSOCIATED WITH THE APPROACHING UPPER TROUGH MOVES IN. WILL
KEEP CHANCE POPS GOING IN THE FORECAST FROM TUESDAY THROUGH NEXT
THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 221500Z TAF UPDATE/...
ISSUED AT 1028 AM EDT FRI AUG 22 2014
AREA OF THUNDERSTORMS HAS WEAKENED SO HAVE PULLED IMMEDIATE THUNDER
THREAT FROM THE TAFS. THERE ARE SOME AREAS OF PATCHY MVFR BOTH IN
AND OUT OF THE RAIN AREAS...SO HAVE PUT TEMPOS IN TO COVER THIS.
MUCH UNCERTAINTY EXISTS IN HOW CONVECTIVE SITUATION WILL EVOLVE
UPSTREAM...SO HAVE JUST PUT IN VCTS AT KIND AND KHUF FOR THE
AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
THUNDERSTORM CLUSTERS CONTINUE TO DROP SOUTHEAST ACROSS NORTHERN
ILLINOIS AND NORTHERN INDIANA. INTENSITY HAS FOR THE MOST PART BEEN
FAIRLY STEADY...ALTHOUGH CLOUD TOPS HAVE SHOWN A TENDENCY TO COOL
OVER THE PAST HOUR. PROFILERS STILL SHOWING DECENT INFLOW OF 25-30
KTS INTO THE CLUSTERS...SO EXPECTING CONVECTION TO CONTINUE FOR
AWHILE LONGER BEFORE WEAKENING LATER THIS MORNING. APPEARS KLAF/KIND
AND PROBABLY KHUF HAVE A GOOD CHANCE OF A DIRECT IMPACT FROM
CONVECTION THROUGH ABOUT 221600Z...WITH LOWER CONFIDENCE AT KBMG.
PERIODS OF IFR VISIBILITY RESTRICTIONS EXPECTED IN THE HEAVIER CELLS.
SHOULD SEE A BREAK IN THE CONVECTIVE THREAT AROUND MIDDAY INTO THE
AFTERNOON HOURS...BUT MODELS SUGGEST A RENEWED THREAT AFTER ABOUT
222100Z-222200Z AND ON INTO THE EVENING HOURS WITH A POTENTIAL UPPER
WAVE MOVING OUT OF THE IOWA REGION.
OUTSIDE OF CONVECTION...CEILINGS GENERALLY ABOVE 050 TODAY WITH
SURFACE WINDS 210-240 AT 6-8 KTS. VARIABLE AND GUSTY WINDS ALONG
WITH LOWER CEILINGS IN AND NEAR CONVECTION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...JAS/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSINDIANAPOLIS
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
630 AM EDT FRI AUG 22 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 235 AM EDT FRI AUG 22 2014
AN ACTIVE AND WARM WEATHER PATTERN WILL REMAIN IN PLACE THROUGH
THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY. THIS WILL ALLOW VERY WARM AND HUMID AIR
TO PUSH INTO THE OHIO VALLEY. MEANWHILE...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES ARE EXPECTED TO PUSH INTO NORTHERN AND
CENTRAL INDIANA ALONG A LINGERING FRONTAL BOUNDARY. THIS WILL
RESULT IN DAILY CHANCES FOR SHOWERS OR STORMS THROUGH THE WEEKEND.
NEXT WEEK ANOTHER FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES
FOR RAIN AND WILL EVENTUALLY BRING A RETURN TO NEAR AVERAGE
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
SURFACE ANALYSIS EARLY THIS MORNING SHOWS A WARM FRONTAL BOUNDARY
IN PLACE ACROSS NORTHERN AND CENTRAL INDIANA...STRETCHING FROM
NEAR CHICAGO TO MUNCIE AND WINCHESTER. RADAR CONTINUES TO SHOW
SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT ALONG THE FRONT.
ALOFT A RIDGE OF HIGH PRESSURE WAS IN PLACE OVER THE LOWER
MISSISSIPPI RIVER VALLEY...ALLOWING FOR UPPER LEVEL WEATHER
DISTURBANCES TO RIDE THE RIDGE AND SPILL ACROSS THE WARM FRONT
ACROSS THE NORTHERN AND CENTRAL INDIANA...ALL THE WHILE BEING A
TRIGGER FOR TSRA. MEANWHILE...A VERY WARM AND MOIST AIR MASS
REMAINS IN PLACE ACROSS CENTRAL INDIANA WITH DEW POINTS IN THE
UPPER 60S AND LOWER 70S. SKIES WERE CLOUDY...FILLED WITH DEBRIS
FROM EARLIER CONVECTION.
MAIN FORECAST CHALLENGE TODAY WILL BE POPS.
GFS AND NAM AGREE TO AN AMPLIFICATION OF THE UPPER RIDGE ACROSS THE
MISSISSIPPI RIVER VALLEY TODAY...HOWEVER THIS WILL STILL RESULT
IN MORE OF THE SAME AS THE UPPER FLOW WILL BE POISED TO SPILL
ALONG THE LINGERING FRONTAL BOUNDARY ACROSS CENTRAL AND NORTHERN
INDIANA. FORECAST SOUNDINGS ACROSS THE AREA TODAY CONTINUE TO SHOW
PLENTY OF MOISTURE AVAILABLE WITH OVER 2 INCHES OF PRECIPITABLE
WATER. FORECAST SOUNDINGS ALSO IMPLY CONDITIONAL INSTABILITY WITH
CAPE IN EXCESS OF 200 J/KG...HOWEVER CONVECTIVE TEMPS ARE IN THE
LOWER 90S...WHICH SEEM A LITTLE HIGH. CONFIDENCE REMAINS LOW IN
ANY SPECIFIC TIMING FOR TSRA TODAY AS GFS AND NAM BOTH FAIL TO
SUGGEST ANY SPECIFIC ORGANIZED WAVE TO PASS ALOFT. HRRR DOES
SUGGEST CONVECTION ACROSS THE NORTHERN PARTS OF THE FORECAST AREA
THIS MORNING...AN GIVEN THE LATEST RADAR TRENDS WILL STEER TOWARD
THIS SOLUTION. HOWEVER GIVEN THE MOIST AIR MASS IN PLACE ALONG
WITH THE LINGERING FRONTAL BOUNDARY...WILL KEEP POPS IN PLACE
THROUGH THE DAY.
AS FOR TEMPS...WITH CLOUDS AND POSSIBLE RAIN TODAY...WILL TREND
TOWARD PERSISTENCE...WHICH SHOULD BE COOLER THAN MAVMOS. WARMER
TEMPS WILL BE FOUND ACROSS THE SW FORECAST AREA WHERE POPS CHANCES
AND CLOUDS WILL BE MUCH LESS...DUE TO PROXIMITY TO THE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
GFS AND NAM SUGGEST LITTLE OVERALL CHANGE IN THE ONGOING PATTERN
TONIGHT AND SATURDAY. THE UPPER RIDGE TO THE WEST CONTINUES TO ALLOW WEAK
UPPER DISTURBANCES TO SPILL SOUTHEAST INTO INDIANA. THE
WARM...HUMID AND CONDITIONALLY UNSTABLE AIRMASS REMAINS IN PLACE.
FORECAST SOUNDINGS REMAIN DEEPLY SATURATED WITH VERY HIGH
PRECIPITABLE WATER VALUES. LINGERING SURFACE BOUNDARY REMAINS IN
PLACE ALSO. THUS WILL RAISE POPS TONIGHT AND ON SATURDAY AS THESE
FEATURES CONTINUE TO REMAIN IN PLACE. GIVEN THE EXPECTED CLOUDS
AND RAIN...WILL CONTINUE TO TREND OF LEANING WARMER THAN MAVMOS ON
LOWS AND COOLER ON HIGHS.
ON SATURDAY NIGHT THROUGH MONDAY...THE UPPER RIDGE AXIS BEGINS TO
DRIFT EAST...WHICH BEGINS TO ALLOW DRIER AIR TO ENTER THE FORECAST
COLUMN. THE UPPER STEERING FLOW BEGINS TO SHIFT ANY RIDGE RIDING
SHORT WAVES WELL EAST OF INDIANA. WITH ET DRIER AIR ARRIVING
PRECIPITABLE WATER IN THE FORECAST SOUNDINGS FALLS TO LESS THAN
1.75 IN. ALSO 700MB TEMPS RISE TOWARD 10C...OFTEN A KEY CAPPING
TEMPERATURE. THUS WILL TREND POPS AT OR BELOW MAVMOS ON SUNDAY
THROUGH MONDAY. AS FOR TEMPS...WILL TREND HIGHS AND LOWS WARMER
THAN MAVMOS GIVEN THE VERY WARM AIR MASS THAT IS EXPECTED ACROSS
THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH NEXT THURSDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
ENSEMBLES SUGGEST UPPER RIDGE INITIALLY OVER THE AREA AT THE
BEGINNING OF THE PERIOD WILL EVENTUALLY GET SUPPRESSED BACK TO THE
SOUTH AS AN UPPER TROUGH MOVES INTO THE NORTHERN MIDWEST OR GREAT
LAKES BY THE MIDDLE OF NEXT WEEK.
ENSEMBLES SUGGEST PRECIPITATION POTENTIAL WILL MOVE BACK INTO THE
AREA STARTING NEXT TUESDAY AS UPPER RIDGE BEGINS TO FLATTEN
OUT...WITH THE BEST CHANCES NEXT WEDNESDAY AND THURSDAY AS A FRONTAL
SYSTEM ASSOCIATED WITH THE APPROACHING UPPER TROUGH MOVES IN. WILL
KEEP CHANCE POPS GOING IN THE FORECAST FROM TUESDAY THROUGH NEXT
THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 221200Z TAFS/...
ISSUED AT 630 AM EDT FRI AUG 22 2014
THUNDERSTORM CLUSTERS CONTINUE TO DROP SOUTHEAST ACROSS NORTHERN
ILLINOIS AND NORTHERN INDIANA. INTENSITY HAS FOR THE MOST PART BEEN
FAIRLY STEADY...ALTHOUGH CLOUD TOPS HAVE SHOWN A TENDENCY TO COOL
OVER THE PAST HOUR. PROFILERS STILL SHOWING DECENT INFLOW OF 25-30
KTS INTO THE CLUSTERS...SO EXPECTING CONVECTION TO CONTINUE FOR
AWHILE LONGER BEFORE WEAKENING LATER THIS MORNING. APPEARS KLAF/KIND
AND PROBABLY KHUF HAVE A GOOD CHANCE OF A DIRECT IMPACT FROM
CONVECTION THROUGH ABOUT 221600Z...WITH LOWER CONFIDENCE AT KBMG.
PERIODS OF IFR VISIBILITY RESTRICTIONS EXPECTED IN THE HEAVIER CELLS.
SHOULD SEE A BREAK IN THE CONVECTIVE THREAT AROUND MIDDAY INTO THE
AFTERNOON HOURS...BUT MODELS SUGGEST A RENEWED THREAT AFTER ABOUT
222100Z-222200Z AND ON INTO THE EVENING HOURS WITH A POTENTIAL UPPER
WAVE MOVING OUT OF THE IOWA REGION.
OUTSIDE OF CONVECTION...CEILINGS GENERALLY ABOVE 050 TODAY WITH
SURFACE WINDS 210-240 AT 6-8 KTS. VARIABLE AND GUSTY WINDS ALONG
WITH LOWER CEILINGS IN AND NEAR CONVECTION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
421 AM EDT FRI AUG 22 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 235 AM EDT FRI AUG 22 2014
AN ACTIVE AND WARM WEATHER PATTERN WILL REMAIN IN PLACE THROUGH
THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY. THIS WILL ALLOW VERY WARM AND HUMID AIR
TO PUSH INTO THE OHIO VALLEY. MEANWHILE...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES ARE EXPECTED TO PUSH INTO NORTHERN AND
CENTRAL INDIANA ALONG A LINGERING FRONTAL BOUNDARY. THIS WILL
RESULT IN DAILY CHANCES FOR SHOWERS OR STORMS THROUGH THE WEEKEND.
NEXT WEEK ANOTHER FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES
FOR RAIN AND WILL EVENTUALLY BRING A RETURN TO NEAR AVERAGE
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
SURFACE ANALYSIS EARLY THIS MORNING SHOWS A WARM FRONTAL BOUNDARY
IN PLACE ACROSS NORTHERN AND CENTRAL INDIANA...STRETCHING FROM
NEAR CHICAGO TO MUNCIE AND WINCHESTER. RADAR CONTINUES TO SHOW
SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT ALONG THE FRONT.
ALOFT A RIDGE OF HIGH PRESSURE WAS IN PLACE OVER THE LOWER
MISSISSIPPI RIVER VALLEY...ALLOWING FOR UPPER LEVEL WEATHER
DISTURBANCES TO RIDE THE RIDGE AND SPILL ACROSS THE WARM FRONT
ACROSS THE NORTHERN AND CENTRAL INDIANA...ALL THE WHILE BEING A
TRIGGER FOR TSRA. MEANWHILE...A VERY WARM AND MOIST AIR MASS
REMAINS IN PLACE ACROSS CENTRAL INDIANA WITH DEW POINTS IN THE
UPPER 60S AND LOWER 70S. SKIES WERE CLOUDY...FILLED WITH DEBRIS
FROM EARLIER CONVECTION.
MAIN FORECAST CHALLENGE TODAY WILL BE POPS.
GFS AND NAM AGREE TO AN AMPLIFICATION OF THE UPPER RIDGE ACROSS THE
MISSISSIPPI RIVER VALLEY TODAY...HOWEVER THIS WILL STILL RESULT
IN MORE OF THE SAME AS THE UPPER FLOW WILL BE POISED TO SPILL
ALONG THE LINGERING FRONTAL BOUNDARY ACROSS CENTRAL AND NORTHERN
INDIANA. FORECAST SOUNDINGS ACROSS THE AREA TODAY CONTINUE TO SHOW
PLENTY OF MOISTURE AVAILABLE WITH OVER 2 INCHES OF PRECIPITABLE
WATER. FORECAST SOUNDINGS ALSO IMPLY CONDITIONAL INSTABILITY WITH
CAPE IN EXCESS OF 200 J/KG...HOWEVER CONVECTIVE TEMPS ARE IN THE
LOWER 90S...WHICH SEEM A LITTLE HIGH. CONFIDENCE REMAINS LOW IN
ANY SPECIFIC TIMING FOR TSRA TODAY AS GFS AND NAM BOTH FAIL TO
SUGGEST ANY SPECIFIC ORGANIZED WAVE TO PASS ALOFT. HRRR DOES
SUGGEST CONVECTION ACROSS THE NORTHERN PARTS OF THE FORECAST AREA
THIS MORNING...AN GIVEN THE LATEST RADAR TRENDS WILL STEER TOWARD
THIS SOLUTION. HOWEVER GIVEN THE MOIST AIR MASS IN PLACE ALONG
WITH THE LINGERING FRONTAL BOUNDARY...WILL KEEP POPS IN PLACE
THROUGH THE DAY.
AS FOR TEMPS...WITH CLOUDS AND POSSIBLE RAIN TODAY...WILL TREND
TOWARD PERSISTENCE...WHICH SHOULD BE COOLER THAN MAVMOS. WARMER
TEMPS WILL BE FOUND ACROSS THE SW FORECAST AREA WHERE POPS CHANCES
AND CLOUDS WILL BE MUCH LESS...DUE TO PROXIMITY TO THE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
GFS AND NAM SUGGEST LITTLE OVERALL CHANGE IN THE ONGOING PATTERN
TONIGHT AND SATURDAY. THE UPPER RIDGE TO THE WEST CONTINUES TO ALLOW WEAK
UPPER DISTURBANCES TO SPILL SOUTHEAST INTO INDIANA. THE
WARM...HUMID AND CONDITIONALLY UNSTABLE AIRMASS REMAINS IN PLACE.
FORECAST SOUNDINGS REMAIN DEEPLY SATURATED WITH VERY HIGH
PRECIPITABLE WATER VALUES. LINGERING SURFACE BOUNDARY REMAINS IN
PLACE ALSO. THUS WILL RAISE POPS TONIGHT AND ON SATURDAY AS THESE
FEATURES CONTINUE TO REMAIN IN PLACE. GIVEN THE EXPECTED CLOUDS
AND RAIN...WILL CONTINUE TO TREND OF LEANING WARMER THAN MAVMOS ON
LOWS AND COOLER ON HIGHS.
ON SATURDAY NIGHT THROUGH MONDAY...THE UPPER RIDGE AXIS BEGINS TO
DRIFT EAST...WHICH BEGINS TO ALLOW DRIER AIR TO ENTER THE FORECAST
COLUMN. THE UPPER STEERING FLOW BEGINS TO SHIFT ANY RIDGE RIDING
SHORT WAVES WELL EAST OF INDIANA. WITH ET DRIER AIR ARRIVING
PRECIPITABLE WATER IN THE FORECAST SOUNDINGS FALLS TO LESS THAN
1.75 IN. ALSO 700MB TEMPS RISE TOWARD 10C...OFTEN A KEY CAPPING
TEMPERATURE. THUS WILL TREND POPS AT OR BELOW MAVMOS ON SUNDAY
THROUGH MONDAY. AS FOR TEMPS...WILL TREND HIGHS AND LOWS WARMER
THAN MAVMOS GIVEN THE VERY WARM AIR MASS THAT IS EXPECTED ACROSS
THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH NEXT THURSDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
ENSEMBLES SUGGEST UPPER RIDGE INITIALLY OVER THE AREA AT THE
BEGINNING OF THE PERIOD WILL EVENTUALLY GET SUPPRESSED BACK TO THE
SOUTH AS AN UPPER TROUGH MOVES INTO THE NORTHERN MIDWEST OR GREAT
LAKES BY THE MIDDLE OF NEXT WEEK.
ENSEMBLES SUGGEST PRECIPITATION POTENTIAL WILL MOVE BACK INTO THE
AREA STARTING NEXT TUESDAY AS UPPER RIDGE BEGINS TO FLATTEN
OUT...WITH THE BEST CHANCES NEXT WEDNESDAY AND THURSDAY AS A FRONTAL
SYSTEM ASSOCIATED WITH THE APPROACHING UPPER TROUGH MOVES IN. WILL
KEEP CHANCE POPS GOING IN THE FORECAST FROM TUESDAY THROUGH NEXT
THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 220900Z KIND TAF UPDATE/...
ISSUED AT 421 AM EDT FRI AUG 22 2014
THUNDERSTORM CLUSTERS CONTINUE TO DROP SOUTHEAST ACROSS NORTHERN
ILLINOIS AND NORTHERN INDIANA. SHORT TERM MODELS SUGGEST 850MB FLOW
INTO THE CLUSTERS MAY BEGIN TO WEAKEN OVER THE NEXT COUPLE OF
HOURS...BUT STILL LOOKS LIKE A GOOD CHANCE FOR AN IMPACT AT KIND
AFTER 221200Z-221300Z.
PREVIOUS DISCUSSION FOLLOWS.
ADDITIONAL SHOWERS WERE MOVING EAST ACROSS NORTHERN ILLINOIS EARLY
THIS OVERNIGHT ALONG STATIONARY FRONT THAT EXTENDS SOUTHEAST ACROSS
THE NORTHERN TAF SITES AND OVER AN UPPER RIDGE. THE 01Z RAPID
REFRESH REFLECTIVITY PROGS LOOK REASONABLE BRINGING THIS ACTIVITY IN
THE VICINITY OF THE NORTHERN TAF SITES OVERNIGHT. WILL GO WITH VCSH
AT THE START OF THE 06Z TAFS AT LAF AND IND BASED ON RADAR AND
LIGHTNING TRENDS AND THEN VCTS SHORTLY THEREAFTER. WILL ALSO KEEP
VCTS AT LAF AND IND TOMORROW AFTER 20Z AS A COLD FRONT DROPS
SOUTHEAST ACROSS NORTHERN ILLINOIS. CAP WILL LIKELY KEEP ACTIVITY TO
SCATTERED AT THE OTHER SITES...TOO LITTLE COVERAGE FOR ANY
THUNDERSTORM MENTION.
COULD SEE SOME MVFR AND WORSE FOG OVERNIGHT AS WINDS BECOMING VERY
LIGHT. OTHERWISE...SOUTH WINDS WILL BECOME SOUTHWEST AND WEST
TOMORROW MORNING BUT STILL LESS THAN 10 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...MK/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
235 AM EDT FRI AUG 22 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 235 AM EDT FRI AUG 22 2014
AN ACTIVE AND WARM WEATHER PATTERN WILL REMAIN IN PLACE THROUGH
THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY. THIS WILL ALLOW VERY WARM AND HUMID AIR
TO PUSH INTO THE OHIO VALLEY. MEANWHILE...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES ARE EXPECTED TO PUSH INTO NORTHERN AND
CENTRAL INDIANA ALONG A LINGERING FRONTAL BOUNDARY. THIS WILL
RESULT IN DAILY CHANCES FOR SHOWERS OR STORMS THROUGH THE WEEKEND.
NEXT WEEK ANOTHER FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES
FOR RAIN AND WILL EVENTUALLY BRING A RETURN TO NEAR AVERAGE
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
SURFACE ANALYSIS EARLY THIS MORNING SHOWS A WARM FRONTAL BOUNDARY
IN PLACE ACROSS NORTHERN AND CENTRAL INDIANA...STRETCHING FROM
NEAR CHICAGO TO MUNCIE AND WINCHESTER. RADAR CONTINUES TO SHOW
SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT ALONG THE FRONT.
ALOFT A RIDGE OF HIGH PRESSURE WAS IN PLACE OVER THE LOWER
MISSISSIPPI RIVER VALLEY...ALLOWING FOR UPPER LEVEL WEATHER
DISTURBANCES TO RIDE THE RIDGE AND SPILL ACROSS THE WARM FRONT
ACROSS THE NORTHERN AND CENTRAL INDIANA...ALL THE WHILE BEING A
TRIGGER FOR TSRA. MEANWHILE...A VERY WARM AND MOIST AIR MASS
REMAINS IN PLACE ACROSS CENTRAL INDIANA WITH DEW POINTS IN THE
UPPER 60S AND LOWER 70S. SKIES WERE CLOUDY...FILLED WITH DEBRIS
FROM EARLIER CONVECTION.
MAIN FORECAST CHALLENGE TODAY WILL BE POPS.
GFS AND NAM AGREE TO AN AMPLIFICATION OF THE UPPER RIDGE ACROSS THE
MISSISSIPPI RIVER VALLEY TODAY...HOWEVER THIS WILL STILL RESULT
IN MORE OF THE SAME AS THE UPPER FLOW WILL BE POISED TO SPILL
ALONG THE LINGERING FRONTAL BOUNDARY ACROSS CENTRAL AND NORTHERN
INDIANA. FORECAST SOUNDINGS ACROSS THE AREA TODAY CONTINUE TO SHOW
PLENTY OF MOISTURE AVAILABLE WITH OVER 2 INCHES OF PRECIPITABLE
WATER. FORECAST SOUNDINGS ALSO IMPLY CONDITIONAL INSTABILITY WITH
CAPE IN EXCESS OF 200 J/KG...HOWEVER CONVECTIVE TEMPS ARE IN THE
LOWER 90S...WHICH SEEM A LITTLE HIGH. CONFIDENCE REMAINS LOW IN
ANY SPECIFIC TIMING FOR TSRA TODAY AS GFS AND NAM BOTH FAIL TO
SUGGEST ANY SPECIFIC ORGANIZED WAVE TO PASS ALOFT. HRRR DOES
SUGGEST CONVECTION ACROSS THE NORTHERN PARTS OF THE FORECAST AREA
THIS MORNING...AN GIVEN THE LATEST RADAR TRENDS WILL STEER TOWARD
THIS SOLUTION. HOWEVER GIVEN THE MOIST AIR MASS IN PLACE ALONG
WITH THE LINGERING FRONTAL BOUNDARY...WILL KEEP POPS IN PLACE
THROUGH THE DAY.
AS FOR TEMPS...WITH CLOUDS AND POSSIBLE RAIN TODAY...WILL TREND
TOWARD PERSISTENCE...WHICH SHOULD BE COOLER THAN MAVMOS. WARMER
TEMPS WILL BE FOUND ACROSS THE SW FORECAST AREA WHERE POPS CHANCES
AND CLOUDS WILL BE MUCH LESS...DUE TO PROXIMITY TO THE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
GFS AND NAM SUGGEST LITTLE OVERALL CHANGE IN THE ONGOING PATTERN
TONIGHT AND SATURDAY. THE UPPER RIDGE TO THE WEST CONTINUES TO ALLOW WEAK
UPPER DISTURBANCES TO SPILL SOUTHEAST INTO INDIANA. THE
WARM...HUMID AND CONDITIONALLY UNSTABLE AIRMASS REMAINS IN PLACE.
FORECAST SOUNDINGS REMAIN DEEPLY SATURATED WITH VERY HIGH
PRECIPITABLE WATER VALUES. LINGERING SURFACE BOUNDARY REMAINS IN
PLACE ALSO. THUS WILL RAISE POPS TONIGHT AND ON SATURDAY AS THESE
FEATURES CONTINUE TO REMAIN IN PLACE. GIVEN THE EXPECTED CLOUDS
AND RAIN...WILL CONTINUE TO TREND OF LEANING WARMER THAN MAVMOS ON
LOWS AND COOLER ON HIGHS.
ON SATURDAY NIGHT THROUGH MONDAY...THE UPPER RIDGE AXIS BEGINS TO
DRIFT EAST...WHICH BEGINS TO ALLOW DRIER AIR TO ENTER THE FORECAST
COLUMN. THE UPPER STEERING FLOW BEGINS TO SHIFT ANY RIDGE RIDING
SHORT WAVES WELL EAST OF INDIANA. WITH ET DRIER AIR ARRIVING
PRECIPITABLE WATER IN THE FORECAST SOUNDINGS FALLS TO LESS THAN
1.75 IN. ALSO 700MB TEMPS RISE TOWARD 10C...OFTEN A KEY CAPPING
TEMPERATURE. THUS WILL TREND POPS AT OR BELOW MAVMOS ON SUNDAY
THROUGH MONDAY. AS FOR TEMPS...WILL TREND HIGHS AND LOWS WARMER
THAN MAVMOS GIVEN THE VERY WARM AIR MASS THAT IS EXPECTED ACROSS
THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH NEXT THURSDAY/...
ISSUED AT 235 AM EDT FRI AUG 22 2014
ENSEMBLES SUGGEST UPPER RIDGE INITIALLY OVER THE AREA AT THE
BEGINNING OF THE PERIOD WILL EVENTUALLY GET SUPPRESSED BACK TO THE
SOUTH AS AN UPPER TROUGH MOVES INTO THE NORTHERN MIDWEST OR GREAT
LAKES BY THE MIDDLE OF NEXT WEEK.
ENSEMBLES SUGGEST PRECIPITATION POTENTIAL WILL MOVE BACK INTO THE
AREA STARTING NEXT TUESDAY AS UPPER RIDGE BEGINS TO FLATTEN
OUT...WITH THE BEST CHANCES NEXT WEDNESDAY AND THURSDAY AS A FRONTAL
SYSTEM ASSOCIATED WITH THE APPROACHING UPPER TROUGH MOVES IN. WILL
KEEP CHANCE POPS GOING IN THE FORECAST FROM TUESDAY THROUGH NEXT
THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 220600Z TAF ISSUANCE/...
ISSUED AT 1234 AM EDT FRI AUG 22 2014
ADDITIONAL SHOWERS WERE MOVING EAST ACROSS NORTHERN ILLINOIS EARLY
THIS OVERNIGHT ALONG STATIONARY FRONT THAT EXTENDS SOUTHEAST ACROSS
THE NORTHERN TAF SITES AND OVER AN UPPER RIDGE. THE 01Z RAPID
REFRESH REFLECTIVITY PROGS LOOK REASONABLE BRINGING THIS ACTIVITY IN
THE VICINITY OF THE NORTHERN TAF SITES OVERNIGHT. WILL GO WITH VCSH
AT THE START OF THE 06Z TAFS AT LAF AND IND BASED ON RADAR AND
LIGHTNING TRENDS AND THEN VCTS SHORTLY THEREAFTER. WILL ALSO KEEP
VCTS AT LAF AND IND TOMORROW AFTER 20Z AS A COLD FRONT DROPS
SOUTHEAST ACROSS NORTHERN ILLINOIS. CAP WILL LIKELY KEEP ACTIVITY TO
SCATTERED AT THE OTHER SITES...TOO LITTLE COVERAGE FOR ANY
THUNDERSTORM MENTION.
COULD SEE SOME MVFR AND WORSE FOG OVERNIGHT AS WINDS BECOMING VERY
LIGHT. OTHERWISE...SOUTH WINDS WILL BECOME SOUTHWEST AND WEST
TOMORROW MORNING BUT STILL LESS THAN 10 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...MK/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
145 AM EDT FRI AUG 22 2014
.SYNOPSIS...
ISSUED AT 310 PM EDT THU AUG 21 2014
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE GREAT
LAKES AND OHIO VALLEY REGIONS TONIGHT. THESE DISTURBANCES WILL
INTERACT WITH A STALLED FRONTAL BOUNDARY ACROSS THE REGION AND
ABUNDANT LOW LEVEL MOISTURE TO PRODUCE A GOOD CHANCE OF SHOWERS
AND THUNDERSTORMS TONIGHT INTO EARLY FRIDAY. AN UPPER LEVEL RIDGE
WILL BUILD INTO THE REGION FRIDAY NIGHT AND SATURDAY WITH HOT AND
HUMID CONDITIONS...ALONG WITH THE POSSIBILITY OF ISOLATED
THUNDERSTORMS. LOW TEMPERATURES TONIGHT WILL DROP INTO THE UPPER
60S AND LOWER 70S. HIGH TEMPERATURES ON FRIDAY WILL RANGE FROM THE
LOWER TO MID 80S ACROSS CENTRAL LOWER MICHIGAN...TO AROUND 90
ACROSS NORTHEAST ILLINOIS AND CENTRAL INDIANA.
&&
.UPDATE...
ISSUED AT 142 AM EDT FRI AUG 22 2014
RADAR TRENDS CONTINUE TO EXPAND WITH A NARROW LINE OF
SHOWERS/STORMS IN WEST INDIANA AND A LARGE CLUSTER OF STORMS
MOVING ACROSS PORTIONS OF NORTHERN/CENTRAL ILLINOIS. THE INITIAL
LINE WAS MOVING ESE WITH THE CLUSTER GENERALLY EAST AT ONLY AROUND
20 TO 25 MPH. SPC MESO ANALYSIS INDICATED UPWARDS OF 2000 J/KG OF
MOST UNSTABLE CAPE (AN INCREASE OVER THE PAST FEW HOURS) WITH
PRECIPITABLE WATERS OVER 2 INCHES AND CORFIDI VECTORS BARELY 10
KNOTS. THIS COMBINED WITH THE RECENT RAINFALL IN THE SW MAY LEAD
TO AN INCREASED THREAT OF FLOODING IN SOME AREAS. WILL MONITOR
OVER THE NEXT HOURS OR 2 TO SEE WHERE THE HEAVIEST PRECIP MAY
TRACK AND DECIDE THE BEST COURSE OF ACTION FOR ANY HYDRO CONCERNS
AS HRRR AND RUC SEEM TO POINT TOWARDS THE HEAVIEST RAIN REMAINING
JUST TO THE NE OF THE GREATEST AREA OF CONCERN. ANOTHER GRID
UPDATE WILL BE NEEDED TO REFLECT THE PREVIOUSLY MENTIONED CONCERN
FOR EXPANSION OF ACTIVITY FURTHER NORTH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM EDT THU AUG 21 2014
THE NEXT IN A SERIES OF SMALL SCALE SHORT WAVES ACROSS SOUTHEAST
WISCONSIN WILL DROP EAST SOUTHEAST OVER THE NEXT FEW HOURS
RESULTING IN INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS.
CONVECTION EARLIER THIS AFTERNOON HAS STABILIZED CONDITIONS
SOMEWHAT FOR SFC BASED PARCELS...BUT WELL-ESTABLISHED AXIS OF
POOLED LOW LEVEL MOISTURE WILL ALLOW FOR MODERATE ELEVATED
INSTABILITY AND SCATTERED THUNDERSTORMS. SHOWERS ALSO APPEAR TO BE
FOCUSING LATE THIS AFTERNOON ON AXIS OF DIFFERENTIAL HEATING FROM
VPZ-RCR-AOH. SHEAR PROFILES WILL BE STEADILY ON THE INCREASE OVER
THE NEXT SEVERAL HOURS HOWEVER...AS BELT OF STRONGER UPPER LEVEL
WESTERLIES OVERSPREADS THE SOUTHERN GREAT LAKES REGION. LIMITING
FACTORS TO INSTABILITY SHOULD TEND TO MITIGATE SEVERE POTENTIAL
OVER THE NEXT SEVERAL HOURS. NEXT UPPER LEVEL SHORT WAVE
PROGRESSING THROUGH MEAN RIDGE ACROSS EASTERN IOWA/NORTHWEST
ILLINOIS SHOULD ALLOW FOR CONTINUED BROAD ISENTROPIC ASCENT OVER
LOW LEVEL BOUNDARY ACROSS THE REGION...WITH CONTINUED THUNDER
CHANCES LATE EVENING INTO THE EARLY PORTION OF THE OVERNIGHT. SOME
LOW END SEVERE POTENTIAL MAY EXIST IF UPSTREAM CONVECTION CAN
CONGEAL LATER THIS EVENING...WHICH CANNOT BE RULED OUT GIVEN
STRENGTHENING BACKGROUND SHEAR PROFILES. OTHER CONCERN FOR TONIGHT
WILL BE POSSIBLE HYDRO IMPACTS. SHOWERS/STORMS EARLIER TODAY LAID
OUT AN AXIS OF 1-2 INCH RAINFALL AMOUNTS FROM WESTERN STARKE
COUNTY INTO GRANT COUNTY. THIS CORRIDOR SHOULD REPRESENT BEST
OVERALL ELEVATED INSTABILITY TONIGHT...AND WITH LITTLE
DISPLACEMENT OF NEARLY 2 INCH PWAT AXIS AND WARM CLOUD DEPTHS
GREATER THAN 12K FT...CANNOT RULE SOME LOCALIZED HEAVY RAINFALL.
WITH STILL SOME UNCERTAINTIES ON HOW UPSTREAM CONVECTION WILL
EVOLVE TONIGHT...AND A FAIRLY SIZABLE TEMPORAL GAP FROM THIS
MORNINGS HEAVY RAINFALL...HAVE OPTED TO HOLD OFF ON ANY HYDRO
HEADLINES AT THIS TIME.
AFOREMENTIONED IOWA SHORT WAVE WILL BECOME MORE SHEARED IN NATURE
ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES TONIGHT INTO EARLY
FRIDAY MORNING AND PROVIDE BEST FORCING TO EASTERN PORTIONS OF THE
AREA BY AFTERNOON. MID LEVEL HEIGHT RISES WILL SLOWLY BUILD IN
FROM THE WEST DURING THE DAY ALSO...WHICH SHOULD TEND TO
LIMIT CONVECTIVE COVERAGE ACROSS FAR WESTERN AREAS BY LATE
AFTERNOON. HAVE MAINTAINED HIGH CHANCE POPS INTO FRIDAY
MORNING...WITH GRADUALLY DIMINISHING POPS FROM WEST TO EAST
DURING THE AFTERNOON. IF GOOD DEAL OF INSOLATION CAN BE
REALIZED...TEMPERATURES COULD REACH INTO THE LOWER 90S ACROSS
SOUTHWEST PORTIONS OF THE AREA LATE AFTERNOON...WITH HEAT INDICES
PUSHING NEAR THE 100 DEGREE MARK. GREATER CLOUD COVER/PRECIP
SHOULD ALLOW FOR HEAT INDICES REMAINING IN THE LOWER 90S ACROSS
THE EASTERN HALF.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM EDT THU AUG 21 2014
UPPER LEVEL RIDGE WILL BUILD NORTHEAST INTO THE GREAT LAKES REGION
THIS WEEKEND INTO EARLY NEXT WEEK WHICH WILL SUPPORT A TREND TOWARD
HOT/MAINLY DRY WX. RETAINED LOW CHANCES FOR SHOWERS/STORMS FRIDAY
NIGHT INTO SATURDAY...MAINLY SOUTHWEST WHERE LOW LEVEL THETA-E
GRADIENT REMAINS ANCHORED AS COOLER EASTERLY DRAINAGE FLOW INTO
OUR NORTHEASTERN ZONES LIMITS NORTHEAST MIX OF DIFFUSE INSTABILITY
GRADIENT/BOUNDARY. PRECIP CHANCES REMAIN NONZERO INTO SUNDAY AND
MONDAY GIVEN AN INCREASINGLY MOIST/UNSTABLE BOUNDARY
LAYER...ALTHOUGH WARMING/DRYING ALOFT UNDER UPPER RIDGE AXIS SUGGEST
HOLDING WITH A DRY FCST (10 POP) STILL THE WAY TO GO.
GRADUAL EASTWARD DRIFT OF A WESTERN CONUS UPPER TROUGH INTO THE
NORTH-CENTRAL US WILL EVENTUALLY FLATTEN UPPER RIDGE IN PLACE...
WITH MOISTURE CHANNEL/THETA-E FOLD INTO THE LOWER LAKES SUPPORTING
INCREASING CHANCES FOR SHOWERS/STORMS. MODELS CONTINUE TO DIFFER
WITH TIMING/AMPLITUDE OF THIS FEATURE RESULTING IN LOW CONFIDENCE
POP/TEMP FCST TUESDAY AND BEYOND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 130 AM EDT FRI AUG 22 2014
STORMY 3 TO 6 HOUR PERIOD LOOKS TO BE IN STORE FOR AT LEAST KSBN
AND LIKELY KFWA (JUST DELAYED AN HOUR OR 2) AS CONVECTION
CONTINUES TO EXPAND ACROSS FAR WESTERN INDIANA BACK INTO NORTHERN
ILLINOIS. A DEVELOPING LINE OF SHOWERS/STORMS WILL DRIFT EAST AND
IMPACT KSBN AROUND 7Z. A LARGER CLUSTER OF STORMS WAS LOCATED WEST
OF KJOT AND WORKING EAST AND SOMEWHAT SE. THIS MAY AFFECT KSBN BUT
THINK IMPACTS ON FWA COULD BE GREATER. HAVE HANDLED WITH TEMPO
GROUPS FOR NOW AND WILL MONITOR COVERAGE.
ADDITIONAL SHOWERS AND STORMS COULD DEVELOP JUST ABOUT ANY TIME THROUGH
THE TAF PERIOD BUT WILL LEAVE ANY ADDITIONAL DETAILS OUT FOR NOW.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...STEINWEDEL
AVIATION...FISHER
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1253 PM CDT FRI AUG 22 2014
.UPDATE...
SENDING UPDATE TO LOWER MAX TEMPS A BIT DUE TO LINGERING DEBRIS
CLOUDINESS...WITH HIGHS MAINLY IN THE 80S. ALSO...UPDATED POPS
TO BETTER REFLECT CURRENT TRENDS.
&&
.PREV DISCUSSION... /ISSUED 328 AM CDT FRI AUG 22 2014/
SYNOPSIS...
ISSUED AT 328 AM CDT FRI AUG 22 2014
ALOFT...UPPER RIDGE PERSISTS OVER THE MISSISSIPPI VALLEY. SURFACE
LOW NEAR KLSE THIS MORNING WITH A STATIONARY FRONT EXTENDING TO ITS
SOUTHWEST INTO COLORADO AND ALSO TO ITS EAST INTO THE GREAT LAKES.
THUNDERSTORMS THIS MORNING FUELED BY LLJ...WARM SECTOR DEW POINTS IN
THE 70S...AND APPROACHING MCV.
SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT FRI AUG 22 2014
AREA OF CONVECTION OVER SOUTH CENTRAL IOWA SHOULD PERSIST THROUGH
SUNRISE AND AFFECT SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS. SHORT RANGE
MODELS INCLUDING THE HRRR AND RUC WEAKEN THE CONVECTION AFTER
SUNRISE...WHICH MAKES SENSE GIVEN THE DIURNAL TREND OF THE LLJ.
HOWEVER...MODELS HAVE TYPICALLY BEEN TOO QUICK TO SQUELCH
CONVECTION...AND THUS BELIEVE IT WILL LINGER A BIT LONGER THAN
PROGGED AND WILL HANG ON TO POPS IN THE SOUTHERN HALF OF THE CWFA
LONGER THAN MESOSCALE MODELS WOULD SUGGEST.
ANOTHER ROUND OF STORMS EXPECTED THIS AFTERNOON AS THE SURFACE LOW
CONTINUES TO SAG EVER SO SLIGHTLY FARTHER SOUTH AND THE FRONT
REMAINS STALLED OVER NRN MO/SRN IA. OF COURSE EXACT POSITIONING OF
STORMS REMAINS UNCERTAIN...IN PARTICULAR WITH SO MANY BOUNDARIES
AROUND. CURRENT THINKING IS THAT FAVORED AREA IS ALONG AND JUST
SOUTH OF I80 WHERE THE 850 MB FRONT IS PROGGED TO SET UP.
REGARDLESS OF EXACT LOCATION...EXPECT INTENSE RAINFALL RATES DUE TO
HIGH PRECIPITABLE WATERS AT OR ABOVE 2 INCHES.
ACTIVE WEATHER CONTINUES THROUGH TONIGHT WITH BOUNDARIES LINGERING
AND POTENTIAL FOR UPPER WAVES COMING OUT OF THE WSW.
LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CDT FRI AUG 22 2014
THE PERSISTENT RING OF FIRE PATTERN CONTINUES THROUGH THE WEEKEND
PRESENTING A THREAT FOR HOT AND HUMID CONDITIONS OUTSIDE THE
OCCASIONAL MESOSCALE CONVECTIVE COMPLEXES LIKELY TO IMPACT PARTS OF
THE REGION. THE UPPER LEVEL RIDGE IS THEN EXPECTED TO BREAK DOWN AND
SHIFT EASTWARD BY THE MIDDLE PART OF NEXT WEEK. THIS WILL ALLOW
CANADIAN HIGH PRESSURE TO BUILD INTO THE AREA...RETURNING
TEMPERATURES CLOSER TO LATE AUGUST NORMALS AND PROVIDING A PERIOD OF
DRIER WEATHER.
SATURDAY AND SUNDAY...LOW PRESSURE LIFTING NORTHEAST THROUGH THE
NORTHERN PLAINS WILL LIFT THE LOW LEVEL BOUNDARY/WARM FRONT
NORTHWARD THROUGH THE FORECAST AREA SATURDAY. THE ASSOCIATED WARM
ADVECTION AND STRENGTHENING MID LEVEL CAP WILL LIMIT THUNDERSTORM
CHANCES TO THE NORTHEAST HALF OF THE FORECAST AREA. WITH DEW POINTS
EASILY IN THE LOWER TO MID 70S...VERY MUGGY CONDITIONS WILL
CONTINUE. MAX TEMPERATURES WILL CONTINUE TO BE A CHALLENGE DUE TO
UNCERTAINTY IN CONVECTIVE TRENDS AND ASSOCIATED CLOUD COVER. WITH
SURFACE WINDS MORE SOUTHEASTERLY...WILL BIAS TOWARD THE LOWER END OF
GUIDANCE WITH HIGHS FROM THE MID 80S NORTHEAST TO LOWER 90S SOUTH.
THIS WOULD STILL RESULT IN HEAT INDEX READINGS NEAR TO JUST ABOVE
100 SOUTH OF I-80 IN THE AFTERNOON HOURS. SATURDAY NIGHT THROUGH
SUNDAY...THE AREA WILL FALL INTO THE MORE DEEPLY MIXED BUT CAPPED
WARM SECTOR WITH 850 MB TEMPERATURES SUPPORTIVE OF WIDESPREAD HIGHS
IN THE UPPER 80S TO LOWER 90S AND POSSIBLY WARMER DEPENDING ON THE
AMOUNT OF CLOUD COVER. THIS WOULD RESULT IN POSSIBLY ANOTHER DAY OF
100 PLUS HEAT INDEX VALUES AND MAY REQUIRE HEAT HEADLINES OVER AT
LEAST THE SOUTH.
MONDAY THROUGH THURSDAY...MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
TIMING OF THE BOTH THE INITIAL EARLY WEEK FRONTAL PASSAGE AND THE
STRONGER COLD FRONT AROUND WED AND THU. THE ECMWF AND CANADIAN HAVE
THE INITIAL FRONT PUSHING THROUGH INTO CENTRAL IL AND MO
MONDAY...WHILE THE GFS HOLDS IT WELL TO THE NW. OUR FORECAST WILL
CONTINUE A LOW CONFIDENCE BLENDED APPROACH WITH THUNDERSTORM CHANCES
RETURNING LATE MONDAY AND CONTINUING THROUGH THURSDAY. THE PAST
COUPLE RUNS WERE TRENDING TOWARD A GREATER LIKELIHOOD OF A DRY
THURSDAY AS HIGH PRESSURE BUILDS IN. WARM TO VERY WARM AND CONTINUED
HIGH HUMIDITY SUGGEST A POSSIBLE NEED FOR HEAT HEADLINES AT LEAST IN
THE AFTERNOON HOURS FOR MONDAY AND TUESDAY WHERE HIGHS ARE
MAINTAINED IN THE UPPER 80S TO LOWER 90S WITH OVERNIGHT LOWS HOLDING
IN THE 70S FOR MUCH OF THE AREA. TEMPERATURES ARE TRENDING A BIT
COOLER...FOR WED AND THU AS THE CONTINUITY IN SUCCESSIVE MODEL RUNS
BACK THE TIMING OF THE PATTERN CHANGE AND PLACEMENT OF THE IN-COMING
HIGH.
AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 1253 PM CDT FRI AUG 22 2014
LIFR CONDITIONS AT KDBQ WILL SLOWLY IMPROVE TO MVFR BY SUNSET.
OTHERWISE EXPECT VFR CONDITIONS THROUGH SUNSET WITH ISOLATED
TSRA/SHRA POSSIBLE. AFT SUNSET ANOTHER THUNDERSTORM COMPLEX WILL
DEVELOP...POSSIBLY IN SOUTHWEST IOWA. THIS THUNDERSTORM COMPLEX
SHOULD MOVE EAST OR EAST SOUTHEAST THROUGH SUNRISE. CONDITIONS WILL
SLOWLY DETERIORATE TO MVFR AND POSSIBLY IFR CONDITIONS AT
KCID/KMLI/KBRL. KDBQ WILL DETERIORATE TO IFR AND POSSIBLY LIFR
CONDITIONS WITH NEARBY SHOWERS POSSIBLE.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 AM CDT FRI AUG 22 2014
.UPDATE...
SENDING UPDATE TO LOWER MAX TEMPS A BIT DUE TO LINGERING DEBRIS
CLOUDINESS...WITH HIGHS MAINLY IN THE 80S. ALSO...UPDATED POPS
TO BETTER REFLECT CURRENT TRENDS.
&&
.PREV DISCUSSION... /ISSUED 328 AM CDT FRI AUG 22 2014/
SYNOPSIS...
ISSUED AT 328 AM CDT FRI AUG 22 2014
ALOFT...UPPER RIDGE PERSISTS OVER THE MISSISSIPPI VALLEY. SURFACE
LOW NEAR KLSE THIS MORNING WITH A STATIONARY FRONT EXTENDING TO ITS
SOUTHWEST INTO COLORADO AND ALSO TO ITS EAST INTO THE GREAT LAKES.
THUNDERSTORMS THIS MORNING FUELED BY LLJ...WARM SECTOR DEW POINTS IN
THE 70S...AND APPROACHING MCV.
SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT FRI AUG 22 2014
AREA OF CONVECTION OVER SOUTH CENTRAL IOWA SHOULD PERSIST THROUGH
SUNRISE AND AFFECT SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS. SHORT RANGE
MODELS INCLUDING THE HRRR AND RUC WEAKEN THE CONVECTION AFTER
SUNRISE...WHICH MAKES SENSE GIVEN THE DIURNAL TREND OF THE LLJ.
HOWEVER...MODELS HAVE TYPICALLY BEEN TOO QUICK TO SQUELCH
CONVECTION...AND THUS BELIEVE IT WILL LINGER A BIT LONGER THAN
PROGGED AND WILL HANG ON TO POPS IN THE SOUTHERN HALF OF THE CWFA
LONGER THAN MESOSCALE MODELS WOULD SUGGEST.
ANOTHER ROUND OF STORMS EXPECTED THIS AFTERNOON AS THE SURFACE LOW
CONTINUES TO SAG EVER SO SLIGHTLY FARTHER SOUTH AND THE FRONT
REMAINS STALLED OVER NRN MO/SRN IA. OF COURSE EXACT POSITIONING OF
STORMS REMAINS UNCERTAIN...IN PARTICULAR WITH SO MANY BOUNDARIES
AROUND. CURRENT THINKING IS THAT FAVORED AREA IS ALONG AND JUST
SOUTH OF I80 WHERE THE 850 MB FRONT IS PROGGED TO SET UP.
REGARDLESS OF EXACT LOCATION...EXPECT INTENSE RAINFALL RATES DUE TO
HIGH PRECIPITABLE WATERS AT OR ABOVE 2 INCHES.
ACTIVE WEATHER CONTINUES THROUGH TONIGHT WITH BOUNDARIES LINGERING
AND POTENTIAL FOR UPPER WAVES COMING OUT OF THE WSW.
LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CDT FRI AUG 22 2014
THE PERSISTENT RING OF FIRE PATTERN CONTINUES THROUGH THE WEEKEND
PRESENTING A THREAT FOR HOT AND HUMID CONDITIONS OUTSIDE THE
OCCASIONAL MESOSCALE CONVECTIVE COMPLEXES LIKELY TO IMPACT PARTS OF
THE REGION. THE UPPER LEVEL RIDGE IS THEN EXPECTED TO BREAK DOWN AND
SHIFT EASTWARD BY THE MIDDLE PART OF NEXT WEEK. THIS WILL ALLOW
CANADIAN HIGH PRESSURE TO BUILD INTO THE AREA...RETURNING
TEMPERATURES CLOSER TO LATE AUGUST NORMALS AND PROVIDING A PERIOD OF
DRIER WEATHER.
SATURDAY AND SUNDAY...LOW PRESSURE LIFTING NORTHEAST THROUGH THE
NORTHERN PLAINS WILL LIFT THE LOW LEVEL BOUNDARY/WARM FRONT
NORTHWARD THROUGH THE FORECAST AREA SATURDAY. THE ASSOCIATED WARM
ADVECTION AND STRENGTHENING MID LEVEL CAP WILL LIMIT THUNDERSTORM
CHANCES TO THE NORTHEAST HALF OF THE FORECAST AREA. WITH DEW POINTS
EASILY IN THE LOWER TO MID 70S...VERY MUGGY CONDITIONS WILL
CONTINUE. MAX TEMPERATURES WILL CONTINUE TO BE A CHALLENGE DUE TO
UNCERTAINTY IN CONVECTIVE TRENDS AND ASSOCIATED CLOUD COVER. WITH
SURFACE WINDS MORE SOUTHEASTERLY...WILL BIAS TOWARD THE LOWER END OF
GUIDANCE WITH HIGHS FROM THE MID 80S NORTHEAST TO LOWER 90S SOUTH.
THIS WOULD STILL RESULT IN HEAT INDEX READINGS NEAR TO JUST ABOVE
100 SOUTH OF I-80 IN THE AFTERNOON HOURS. SATURDAY NIGHT THROUGH
SUNDAY...THE AREA WILL FALL INTO THE MORE DEEPLY MIXED BUT CAPPED
WARM SECTOR WITH 850 MB TEMPERATURES SUPPORTIVE OF WIDESPREAD HIGHS
IN THE UPPER 80S TO LOWER 90S AND POSSIBLY WARMER DEPENDING ON THE
AMOUNT OF CLOUD COVER. THIS WOULD RESULT IN POSSIBLY ANOTHER DAY OF
100 PLUS HEAT INDEX VALUES AND MAY REQUIRE HEAT HEADLINES OVER AT
LEAST THE SOUTH.
MONDAY THROUGH THURSDAY...MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
TIMING OF THE BOTH THE INITIAL EARLY WEEK FRONTAL PASSAGE AND THE
STRONGER COLD FRONT AROUND WED AND THU. THE ECMWF AND CANADIAN HAVE
THE INITIAL FRONT PUSHING THROUGH INTO CENTRAL IL AND MO
MONDAY...WHILE THE GFS HOLDS IT WELL TO THE NW. OUR FORECAST WILL
CONTINUE A LOW CONFIDENCE BLENDED APPROACH WITH THUNDERSTORM CHANCES
RETURNING LATE MONDAY AND CONTINUING THROUGH THURSDAY. THE PAST
COUPLE RUNS WERE TRENDING TOWARD A GREATER LIKELIHOOD OF A DRY
THURSDAY AS HIGH PRESSURE BUILDS IN. WARM TO VERY WARM AND CONTINUED
HIGH HUMIDITY SUGGEST A POSSIBLE NEED FOR HEAT HEADLINES AT LEAST IN
THE AFTERNOON HOURS FOR MONDAY AND TUESDAY WHERE HIGHS ARE
MAINTAINED IN THE UPPER 80S TO LOWER 90S WITH OVERNIGHT LOWS HOLDING
IN THE 70S FOR MUCH OF THE AREA. TEMPERATURES ARE TRENDING A BIT
COOLER...FOR WED AND THU AS THE CONTINUITY IN SUCCESSIVE MODEL RUNS
BACK THE TIMING OF THE PATTERN CHANGE AND PLACEMENT OF THE IN-COMING
HIGH.
AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI AUG 22 2014
PATCHY DENSE FOG AFFECTING KCID AND KDBQ WILL LIFT BY MID MORNING.
MEANWHILE...THUNDERSTORMS WILL AFFECT KBRL THIS MORNING AND
SHOWERS WILL MOVE INTO KMLI. LATER TODAY...ANOTHER ROUND OF STORMS IS
POSSIBLE THIS AFTERNOON AND EVENING AT ALL AREA TAF SITES...BUT
THE GREATEST CHANCE IS FOR AREAS MAINLY SOUTH OF I 80.
OTHERWISE...PREVAILING WINDS WILL BE LIGHT AND VARIABLE WITH
GUSTS NEAR THUNDERSTORMS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
634 AM CDT FRI AUG 22 2014
.SYNOPSIS...
ISSUED AT 328 AM CDT FRI AUG 22 2014
ALOFT...UPPER RIDGE PERSISTS OVER THE MISSISSIPPI VALLEY. SURFACE
LOW NEAR KLSE THIS MORNING WITH A STATIONARY FRONT EXTENDING TO ITS
SOUTHWEST INTO COLORADO AND ALSO TO ITS EAST INTO THE GREAT LAKES.
THUNDERSTORMS THIS MORNING FUELED BY LLJ...WARM SECTOR DEW POINTS IN
THE 70S...AND APPROACHING MCV.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT FRI AUG 22 2014
AREA OF CONVECTION OVER SOUTH CENTRAL IOWA SHOULD PERSIST THROUGH
SUNRISE AND AFFECT SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS. SHORT RANGE
MODELS INCLUDING THE HRRR AND RUC WEAKEN THE CONVECTION AFTER
SUNRISE...WHICH MAKES SENSE GIVEN THE DIURNAL TREND OF THE LLJ.
HOWEVER...MODELS HAVE TYPICALLY BEEN TOO QUICK TO SQUELCH
CONVECTION...AND THUS BELIEVE IT WILL LINGER A BIT LONGER THAN
PROGGED AND WILL HANG ON TO POPS IN THE SOUTHERN HALF OF THE CWFA
LONGER THAN MESOSCALE MODELS WOULD SUGGEST.
ANOTHER ROUND OF STORMS EXPECTED THIS AFTERNOON AS THE SURFACE LOW
CONTINUES TO SAG EVER SO SLIGHTLY FARTHER SOUTH AND THE FRONT
REMAINS STALLED OVER NRN MO/SRN IA. OF COURSE EXACT POSITIONING OF
STORMS REMAINS UNCERTAIN...IN PARTICULAR WITH SO MANY BOUNDARIES
AROUND. CURRENT THINKING IS THAT FAVORED AREA IS ALONG AND JUST
SOUTH OF I80 WHERE THE 850 MB FRONT IS PROGGED TO SET UP.
REGARDLESS OF EXACT LOCATION...EXPECT INTENSE RAINFALL RATES DUE TO
HIGH PRECIPITABLE WATERS AT OR ABOVE 2 INCHES.
ACTIVE WEATHER CONTINUES THROUGH TONIGHT WITH BOUNDARIES LINGERING
AND POTENTIAL FOR UPPER WAVES COMING OUT OF THE WSW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CDT FRI AUG 22 2014
THE PERSISTENT RING OF FIRE PATTERN CONTINUES THROUGH THE WEEKEND
PRESENTING A THREAT FOR HOT AND HUMID CONDITIONS OUTSIDE THE
OCCASIONAL MESOSCALE CONVECTIVE COMPLEXES LIKELY TO IMPACT PARTS OF
THE REGION. THE UPPER LEVEL RIDGE IS THEN EXPECTED TO BREAK DOWN AND
SHIFT EASTWARD BY THE MIDDLE PART OF NEXT WEEK. THIS WILL ALLOW
CANADIAN HIGH PRESSURE TO BUILD INTO THE AREA...RETURNING
TEMPERATURES CLOSER TO LATE AUGUST NORMALS AND PROVIDING A PERIOD OF
DRIER WEATHER.
SATURDAY AND SUNDAY...LOW PRESSURE LIFTING NORTHEAST THROUGH THE
NORTHERN PLAINS WILL LIFT THE LOW LEVEL BOUNDARY/WARM FRONT
NORTHWARD THROUGH THE FORECAST AREA SATURDAY. THE ASSOCIATED WARM
ADVECTION AND STRENGTHENING MID LEVEL CAP WILL LIMIT THUNDERSTORM
CHANCES TO THE NORTHEAST HALF OF THE FORECAST AREA. WITH DEW POINTS
EASILY IN THE LOWER TO MID 70S...VERY MUGGY CONDITIONS WILL
CONTINUE. MAX TEMPERATURES WILL CONTINUE TO BE A CHALLENGE DUE TO
UNCERTAINTY IN CONVECTIVE TRENDS AND ASSOCIATED CLOUD COVER. WITH
SURFACE WINDS MORE SOUTHEASTERLY...WILL BIAS TOWARD THE LOWER END OF
GUIDANCE WITH HIGHS FROM THE MID 80S NORTHEAST TO LOWER 90S SOUTH.
THIS WOULD STILL RESULT IN HEAT INDEX READINGS NEAR TO JUST ABOVE
100 SOUTH OF I-80 IN THE AFTERNOON HOURS. SATURDAY NIGHT THROUGH
SUNDAY...THE AREA WILL FALL INTO THE MORE DEEPLY MIXED BUT CAPPED
WARM SECTOR WITH 850 MB TEMPERATURES SUPPORTIVE OF WIDESPREAD HIGHS
IN THE UPPER 80S TO LOWER 90S AND POSSIBLY WARMER DEPENDING ON THE
AMOUNT OF CLOUD COVER. THIS WOULD RESULT IN POSSIBLY ANOTHER DAY OF
100 PLUS HEAT INDEX VALUES AND MAY REQUIRE HEAT HEADLINES OVER AT
LEAST THE SOUTH.
MONDAY THROUGH THURSDAY...MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
TIMING OF THE BOTH THE INITIAL EARLY WEEK FRONTAL PASSAGE AND THE
STRONGER COLD FRONT AROUND WED AND THU. THE ECMWF AND CANADIAN HAVE
THE INITIAL FRONT PUSHING THROUGH INTO CENTRAL IL AND MO
MONDAY...WHILE THE GFS HOLDS IT WELL TO THE NW. OUR FORECAST WILL
CONTINUE A LOW CONFIDENCE BLENDED APPROACH WITH THUNDERSTORM CHANCES
RETURNING LATE MONDAY AND CONTINUING THROUGH THURSDAY. THE PAST
COUPLE RUNS WERE TRENDING TOWARD A GREATER LIKELIHOOD OF A DRY
THURSDAY AS HIGH PRESSURE BUILDS IN. WARM TO VERY WARM AND CONTINUED
HIGH HUMIDITY SUGGEST A POSSIBLE NEED FOR HEAT HEADLINES AT LEAST IN
THE AFTERNOON HOURS FOR MONDAY AND TUESDAY WHERE HIGHS ARE
MAINTAINED IN THE UPPER 80S TO LOWER 90S WITH OVERNIGHT LOWS HOLDING
IN THE 70S FOR MUCH OF THE AREA. TEMPERATURES ARE TRENDING A BIT
COOLER...FOR WED AND THU AS THE CONTINUITY IN SUCCESSIVE MODEL RUNS
BACK THE TIMING OF THE PATTERN CHANGE AND PLACEMENT OF THE IN-COMING
HIGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI AUG 22 2014
PATCHY DENSE FOG AFFECTING KCID AND KDBQ WILL LIFT BY MID MORNING.
MEANWHILE...THUNDERSTORMS WILL AFFECT KBRL THIS MORNING AND
SHOWERS WILL MOVE INTO KMLI. LATER TODAY...ANOTHER ROUND OF STORMS IS
POSSIBLE THIS AFTERNOON AND EVENING AT ALL AREA TAF SITES...BUT
THE GREATEST CHANCE IS FOR AREAS MAINLY SOUTH OF I 80.
OTHERWISE...PREVAILING WINDS WILL BE LIGHT AND VARIABLE WITH
GUSTS NEAR THUNDERSTORMS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
329 AM CDT FRI AUG 22 2014
.SYNOPSIS...
ISSUED AT 328 AM CDT FRI AUG 22 2014
LOFT...UPPER RIDGE PERSISTS OVER THE MISSISSIPPI VALLEY. SURFACE
LOW NEAR KLSE THIS MORNING WITH A STATIONARY FRONT EXTENDING TO ITS
SOUTHWEST INTO COLORADO AND ALSO TO ITS EAST INTO THE GREAT LAKES.
THUNDERSTORMS THIS MORNING FUELED BY LLJ...WARM SECTOR DEW POINTS IN
THE 70S...AND APPROACHING MCV.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT FRI AUG 22 2014
AREA OF CONVECTION OVER SOUTHCENTRAL IOWA SHOULD PERSIST THROUGH
SUNRISE AND AFFECT SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS. SHORT RANGE
MODELS INCLUDING THE HRRR AND RUC WEAKEN THE CONVECTION AFTER
SUNRISE...WHICH MAKES SENSE GIVEN THE DIURNAL TREND OF THE LLJ.
HOWEVER...MODELS HAVE TYPICALLY BEEN TOO QUICK TO SQUELCH
CONVECTION...AND THUS BELIEVE IT WILL LINGER A BIT LONGER THAN
PROGGED AND WILL HANG ON TO POPS IN THE SOUTHERN HALF OF THE CWFA
LONGER THAN MESOSCALE MODELS WOULD SUGGEST.
ANOTHER ROUND OF STORMS EXPECTED THIS AFTERNOON AS THE SURFACE LOW
CONTINUES TO SAG EVER SO SLIGHTLY FARTHER SOUTH AND THE FRONT
REMAINS STALLED OVER NRN MO/SRN IA. OF COURSE EXACT POSITIONING OF
STORMS REMAINS UNCERTAIN...IN PARTICULAR WITH SO MANY BOUNDARIES
AROUND. CURRENT THINKING IS THAT FAVORED AREA IS ALONG AND JUST
SOUTH OF I80 WHERE THE 850 MB FRONT IS PROGGED TO SET UP.
REGARDLESS OF EXACT LOCATION...EXPECT INTENSE RAINFALL RATES DUE TO
HIGH PRECIPITABLE WATERS AT OR ABOVE 2 INCHES.
ACTIVE WEATHER CONTINUES THROUGH TONIGHT WITH BOUNDARIES LINGERING
AND POTENTIAL FOR UPPER WAVES COMING OUT OF THE WSW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 328 AM CDT FRI AUG 22 2014
THE PERSISTENT RING OF FIRE PATTERN CONTINUES THROUGH THE WEEKEND
PRESENTING A THREAT FOR HOT AND HUMID CONDITIONS OUTSIDE THE
OCCASIONAL MESOSCALE CONVECTIVE COMPLEXES LIKELY TO IMPACT PARTS OF
THE REGION. THE UPPER LEVEL RIDGE IS THEN EXPECTED TO BREAK DOWN AND
SHIFT EASTWARD BY THE MIDDLE PART OF NEXT WEEK. THIS WILL ALLOW
CANADIAN HIGH PRESSURE TO BUILD INTO THE AREA...RETURNING
TEMPERATURES CLOSER TO LATE AUGUST NORMALS AND PROVIDING A PERIOD OF
DRIER WEATHER.
SATURDAY AND SUNDAY...LOW PRESSURE LIFTING NORTHEAST THROUGH THE
NORTHERN PLAINS WILL LIFT THE LOW LEVEL BOUNDARY/WARM FRONT
NORTHWARD THROUGH THE FORECAST AREA SATURDAY. THE ASSOCIATED WARM
ADVECTION AND STRENGTHENING MID LEVEL CAP WILL LIMIT THUNDERSTORM
CHANCES TO THE NORTHEAST HALF OF THE FORECAST AREA. WITH DEW POINTS
EASILY IN THE LOWER TO MID 70S...VERY MUGGY CONDITIONS WILL
CONTINUE. MAX TEMPERATURES WILL CONTINUE TO BE A CHALLENGE DUE TO
UNCERTAINTY IN CONVECTIVE TRENDS AND ASSOCIATED CLOUD COVER. WITH
SURFACE WINDS MORE SOUTHEASTERLY...WILL BIAS TOWARD THE LOWER END OF
GUIDANCE WITH HIGHS FROM THE MID 80S NORTHEAST TO LOWER 90S SOUTH.
THIS WOULD STILL RESULT IN HEAT INDEX READINGS NEAR TO JUST ABOVE
100 SOUTH OF I-80 IN THE AFTERNOON HOURS. SATURDAY NIGHT THROUGH
SUNDAY...THE AREA WILL FALL INTO THE MORE DEEPLY MIXED BUT CAPPED
WARM SECTOR WITH 850 MB TEMPERATURES SUPPORTIVE OF WIDESPREAD HIGHS
IN THE UPPER 80S TO LOWER 90S AND POSSIBLY WARMER DEPENDING ON THE
AMOUNT OF CLOUD COVER. THIS WOULD RESULT IN POSSIBLY ANOTHER DAY OF
100 PLUS HEAT INDEX VALUES AND MAY REQUIRE HEAT HEADLINES OVER AT
LEAST THE SOUTH.
MONDAY THROUGH THURSDAY...MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
TIMING OF THE BOTH THE INITIAL EARLY WEEK FRONTAL PASSAGE AND THE
STRONGER COLD FRONT AROUND WED AND THU. THE ECMWF AND CANADIAN HAVE
THE INITIAL FRONT PUSHING THROUGH INTO CENTRAL IL AND MO
MONDAY...WHILE THE GFS HOLDS IT WELL TO THE NW. OUR FORECAST WILL
CONTINUE A LOW CONFIDENCE BLENDED APPROACH WITH THUNDERSTORM CHANCES
RETURNING LATE MONDAY AND CONTINUING THROUGH THURSDAY. THE PAST
COUPLE RUNS WERE TRENDING TOWARD A GREATER LIKELIHOOD OF A DRY
THURSDAY AS HIGH PRESSURE BUILDS IN. WARM TO VERY WARM AND CONTINUED
HIGH HUMIDITY SUGGEST A POSSIBLE NEED FOR HEAT HEADLINES AT LEAST IN
THE AFTERNOON HOURS FOR MONDAY AND TUESDAY WHERE HIGHS ARE
MAINTAINED IN THE UPPER 80S TO LOWER 90S WITH OVERNIGHT LOWS HOLDING
IN THE 70S FOR MUCH OF THE AREA. TEMPERATURES ARE TRENDING A BIT
COOLER...FOR WED AND THU AS THE CONTINUITY IN SUCCESSIVE MODEL RUNS
BACK THE TIMING OF THE PATTERN CHANGE AND PLACEMENT OF THE IN-COMING
HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1130 PM CDT THU AUG 21 2014
LATEST TAFS UPDATED TO FAVOR HRRR/RAP SOLUTIONS...WHICH ARE
MODELING THE CURRENT DEVELOPING CONVECTION WELL. NOW THINKING
STORMS WILL BE MOST PREVALENT AT KMLI/KBRL OVERNIGHT AND HAVE
INTRODUCED 3-4 HOUR TEMPO GROUPS. MORE ISOLATED COVERAGE EXPECTED
AT KCID/KDBQ WITH VCTS GROUPS SUFFICIENT. RECENT TRENDS ALSO
SUPPORT POTENTIAL FOR PERIODS OF IFR CIGS AND/OR VSBYS AT
KCID/KDBQ OVERNIGHT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...RP KINNEY
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1148 PM CDT Thu Aug 21 2014
...AVIATION UPDATE...
.UPDATE...
Issued at 732 PM CDT THU AUG 21 2014
Will be updating the forecast soon to remove the heat advisory as
HI values have fallen below 105 already and temps will continue to
cool. Am a little concerned that we may be dealing with convection
across northern KS for much of the evening. A 00Z objective
surface analysis suggests a weak trough axis or boundary has laid
over more west to east into northeast KS and the outflow from
convection over north central KS will likely help better define
this boundary. Once the low level jet increases this evening,
there could be enough lift along this boundary for scattered
storms to fester through much of the night. This seems to be the
idea anyways from the HRRR and RAP, although they may be a little
to far south with the QPF. Not sure how long a downbust threat
may last as cooling of the boundary layer should increase
convective inhibition. But locally heavy rainfall could be a
concern as models show more than enough moisture (PWs around 2
inches) available for moderate and heavy rainfall. With this in
mind will have tweaked POPs up a little for at least this evening
across north central and northeast KS.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 356 PM CDT THU AUG 21 2014
At 3 PM, surface low pressure was situated over the Oklahoma
panhandle...connected by a weak cold front to another surface low in
southwest Minnesota. There was a second weak boundary, more of a
moisture discontinuity extending from just north of Russel, KS to
near Marysville, KS. immediately north of this moisture boundary,
low-level convergence and the presence of deeper moisture/more
instability have led to persistent showers and a few storms in
southern Nebraska and extreme northern Kansas. Aloft, a stream of
very weak disturbances were moving out of the desert southwest into
the central Plains, and will continue to do so through tomorrow.
Southwest flow aloft on the west side of an upper ridge has allowed
for continuous warm advection and a very hot regime locally.
Temperatures today have been in the upper 90s to lower 100s (with
the exception of areas very close to the NE border where there have
been more clouds) while dewpoints especially north and east have
held in the lower 70s. This has led to heat index values in the 102
to 108 range with the highest values east. Have issued a heat
advisory for northeast and east central KS where the highest T/Td
combinations should be in place through this evening.
This evening into tonight, will be watching a few features for
potential thunderstorm development. The first is the frontal zone in
north central KS. Surface based CAPE greater than 1000 J/kg is in
place in the airmass just north of the weak boundary. Wind shear is
rather weak, but between the ample afternoon heating of the boundary
and what seems to be an incoming weak short wave trough, could see
scattered thunderstorm development in north central KS. If storms
can develop through early evening, the very steep low level lapse
rates would support localized strong downbursts. However, severe
potential appears low as there may not be sufficient
lift/instability to support the precip loading needed for severe
winds. Will need to monitor regardless as the depth of the steep
lapse rates would support damaging winds with only moderate
mid-level downdrafts. As the evening progresses, expect a low level
jet to increase a bit with some weak convergence into north central
KS and a zone of more aggressive moisture transport from south
central into northeast KS. This may further support north central KS
thunderstorms by around 03Z, and could support further development
into northeast KS by late evening and early morning. The chances are
slight for thunderstorms at any given point, and the potential for
severe weather overnight appears even lower yet given the expected
elevated nature of the storms.
Friday is a bit uncertain regarding temperatures and potential heat
headlines. This is mainly due to uncertainty in how long any
scattered precip or remnant cloud cover will be over the area. The
current forecast leans toward a mainly cloud-free late morning and
early afternoon. This, along with slightly warmer 850 temps would
suggest temperatures near or slightly warmer than Thursday with
dewpoints near or slightly lower than Thursday. IF this scenario
plays out, a heat advisory could be needed for parts of the area
again, but given at least some potential for convective debris and
lower temps, have not issued at this time. Will then look to late
afternoon for more potential for scattered storm development, mainly
in northern KS.
.LONG TERM...(Friday Night through Thursday)
Issued at 356 PM CDT THU AUG 21 2014
The mid-level pattern is expected to remain fairly unchanged Friday
night into the weekend as models show the mid-level ridge staying
anchored over much of the southeastern U.S. with the mid-level
trough in place over the western U.S. Friday night into Saturday
this mid-level trough currently over the Pacific Northwest is
expected to deepen and dig southward along the western Rockies
before a strong embedded shortwave trough lifts northeastward toward
the Northern Plains Saturday night into Sunday. As this shortwave
trough pivots northward, it will help to slowly push the stationary
front that will remain stalled out over north central Kansas and
along the Kansas/Nebraska border eastward through the forecast area
Sunday into Monday. Ahead of this frontal passage, southwesterly
surface winds will prevail as surface low pressure remains anchored
over the High Plains. As a result, warm air advection will persist
through the weekend with unseasonably hot conditions. Highs for
Saturday are expected to reach into the mid/upper 90s with afternoon
heat indices rising into the 98F to 102F degree range. As winds
shift to the north with the frontal passage, a slight cool-down is
expected by early next week with highs in the upper 80s to low/mid
90s on Monday. As for precipitation chances through this period,
there is a chance for some isolated nocturnal showers and
thunderstorms Friday night and Saturday night with the help of the
low-level jet, primarily focused over north central Kansas and along
the Kansas/Nebraska border. Thunderstorm chances increase by Sunday
night into Monday with the frontal passage. Models continue to show
this front lifting northward over the region as a warm front by
Monday night, however there are still some model discrepancies with
regards to just how far north this warm front will lift. At this
time though, models seem to be trending toward much of the southern
half of the forecast area being in the warm sector as this boundary
will likely become stationary once again near the Kansas/Nebraska
border through Tuesday night, so expect temperatures to warm up once
again into at least the low/mid 90s and possibly into the upper 90s
for some locations. Tuesday night into Wednesday we may see a repeat
of events as models are showing the stationary boundary once again
transitioning to a cold front that will progress eastward across the
region as a stronger mid-level trough develops and deepens across
the Rockies. This stronger trough should help to finally push this
system east of the area mid-week, with increased precipitation
chances Tuesday night and Wednesday followed by slightly cooler
temperatures in the mid 80s to near 90 degrees.
&&
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1148 PM CDT THU AUG 21 2014
Am quite uncertain whether TS will hold together long enough to
make it into MHK. Profiler data shows a 40KT low level jet from
the south and southwest with the gust front approaching MHK from
the northwest. Think if the gust front was not going to make it
into the terminal, I`d be inclined to keep storms out of the
forecast. However seeing some isolated stuff develop over Lincoln
CO is good enough for me to add a VCTS thinking the gust front
could provide enough lift for some elevated storms. For TOP and
FOE, thinking is the further east the storms move, the more CIN
the will encounter as they move into the heart of the mid level
ridge axis. So will maintain a VFR forecast and continue to
monitor convective trends. Confidence in any model solution is low
as none have done a very good job with this evenings storms.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...Wolters
SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS JACKSON KY
1051 PM EDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 1051 PM EDT SAT AUG 23 2014
SENT OUT ONE LAST UPDATE TO THE FORECAST FOR THIS SHIFT. SHOWERS AND
STORMS OVER THE PAST HOUR OR SO HAVE MADE THEIR WAY INTO PORTIONS OF
PULASKI...WAYNE...AND MCCREARY COUNTIES...SO PRECIPITATION
PROBABILITIES AND QPF AMOUNTS DOWN THERE WERE BEEFED UP THROUGH 4 OR
5Z TONIGHT. WITH ISOLATED STORMS PUSHING SOUTHWARD TOWARD PIKE
COUNTY AND WITH OTHER ISOLATED STUFF HAVING POPPED UP AND DIED IN OUR
BLUEGRASS COUNTIES...DECIDED TO GO AHEAD AND LEAVE IN A SLIGHT CHANCE
OF SHOWERS AND STORMS FOR THE MAJORITY OF THE AREA THROUGH 12Z. THE
EXCEPTION WILL BE WAYNE COUNTY WHERE LIKELY POPS WERE INTRODUCED TO
ACCOUNT FOR THE ENHANCED SHOWER AND STORM ACTIVITY DOWN WHICH APPEARS
IS BEING DRIVEN BY OUTFLOW BOUNDARIES FROM THE STORMS ONGOING IN EAST
CENTRAL KENTUCKY. FOR FORMATION WILL STILL BE OF CONCERN TOO THROUGH
THE OVERNIGHT SO IT WAS AGAIN FEATURED IN THE FORECAST THROUGH 13Z
TOMORROW WITH LOCALLY DENSE FOG POSSIBLE IN OUR VALLEYS.
UPDATE ISSUED AT 733 PM EDT SAT AUG 23 2014
WILL BE SENDING OUT AND UPDATED ZONE FORECAST SHORTLY TO REMOVE THE
PRE FIRST PERIOD PUT IN BY THE DAY SHIFT AND TO DECREASE PRECIPITATION
CHANCES CROSS THE ENTIRE AREA FOR THE REMAINDER OF THE OVERNIGHT
PERIOD INTO EARLY TOMORROW MORNING. THE LATEST NAM12 AND HRRR MODEL
RUNS MATCH UP WELL WITH THE ISOLATED SHOWER AND STORM COVERAGE
CURRENTLY BEING OBSERVED ACROSS EASTERN KENTUCKY. BASED ON THE THE
FACT THAT MOST OF THE LONG LIVED SHOWERS AND STORMS ARE CONFINED TO
CENTRAL KENTUCKY AND WITH THEIR SLOW SOUTHWARD DIRECTION OF
MOVEMENT...AND WITH THE SUN DUE TO SET SOON...IT SIMPLY DOES NOT
APPEAR THAT WE WILL SEE MORE THAN ISOLATED SHOWERS OR STORMS ACROSS
THE MAJORITY OF THE AREA TONIGHT. THERE STILL IS A SMALL CHANCE OF
SCATTERED ACTIVITY WEST OF I75...BUT EVEN THAT IS IN QUESTION AT THIS
POINT. THE FOG FORMATION OVERNIGHT IS ON TRACK...HOWEVER...WITH CLEAR
SKIES...LIGHT WINDS...AND AMPLE SURFACE MOISTURE IN PLACE. WE WILL
STILL LIKELY SEE AREAS OF DENSE FOG LATE TONIGHT INTO EARLY TOMORROW
MORNING...WITH THE MOST FAVORED AREAS BEING OUR VALLEYS. THE NEW
FORECAST WILL REFLECT MUCH LOWER PRECIPITATION CHANCES OVERNIGHT AND
WIDESPREAD FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 350 PM EDT SAT AUG 23 2014
19Z SFC ANALYSIS SHOWS OUR CONTINUING WEATHER CHALLENGE WITH THE LOW
PRESSURE OUT TO THE WEST AND HIGH PRESSURE TO THE SOUTH. A WAVY
NORTHWEST TO SOUTHEAST FRONT EXISTS JUST NORTH OF OUR AREA.
MEANWHILE...ALOFT...A RIDGE IS FOUND THROUGH THE LOWER MIDSECTION OF
THE NATION WITH A DIGGING TROUGH MOVING INTO THE MID ATLANTIC STATES.
THIS PLACES CENTRAL AND EASTERN KENTUCKY IN THE TRACK OF ENERGY
MOVING FROM THE UPPER MIDWEST INTO THE SOUTHERN APPALACHIANS TODAY.
THESE FEATURES HAVE BEEN COMBINING LATELY TO PRODUCE CLUSTERS OF
SHOWERS AND THUNDERSTORMS GENERALLY STARTING IN THE LATE AFTERNOON
AND LASTING INTO THE EVENING. THE HIGH PW AIR IN PLACE OVER THE
AREA...ALONG WITH THE DEWPOINTS PUSHING THE MID 70S...MAKES FOR
PROLIFIC RAIN PRODUCING CELLS. AS HAS BEEN THE CASE REMAINS SO
HEADING INTO LATE AFTERNOON...THOUGH THE AXIS OF CONCERN HAS SHIFTED
SLIGHTLY WEST OWING TO THE WIGGLE OF THE RIDGE IN RESPONSE TO THE
DIGGING TROUGH. CURRENTLY SCATTERED AND ISOLATED SHOWERS/STORMS ARE
DOTTING THE CUMBERLAND VALLEY WITH SIGNS OF LARGER CLUSTERS STARTING
TO TAKE SHAPE TO THE NORTHWEST. THOUGH DELAYED A BIT BY THE LOW
STRATUS DECK FOLLOWING THE DENSE FOG THIS MORNING...TEMPERATURES HAVE
CLIMBED SMARTLY INTO THE MIDDLE AND UPPER 80S THROUGH THE AREA AND
WITH SUCH HIGH DEWPOINTS ARE YIELDING HEAT INDICES IN THE 95 TO 100
DEGREE RANGE. WINDS HAVE BEEN MAINLY LIGHT AND VARIABLE THROUGH THE
AREA.
THE MODELS ARE ALL IN PRETTY GOOD AGREEMENT ALOFT WITH THE WIGGLE
WEST AND THEN BACK EAST OF THE UPPER RIDGE INTO MONDAY MORNING.
SHORTWAVE ENERGY MOVING SOUTH BETWEEN THE UPPER SYSTEMS WILL PASS
THROUGH CENTRAL AND EASTERN KENTUCKY TONIGHT WITH ONLY WEAKER PACKETS
FORESEEN THROUGH THE REST OF THE WEEKEND. GIVEN THE AGREEMENT OF THE
MODELS AND THE SMALLER SCALE NATURE OF CONVECTIVE ACTIVITY OF THIS
REGIME HAVE AGAIN FAVORED THE HRRR AND NAM12 THROUGH THE FIRST 18 TO
36 HOURS AND A MODEL CONSENSUS AFTER THAT INTO MONDAY MORNING.
SENSIBLE WEATHER WILL FEATURE ISOLATED AND SCATTERED CONVECTION
AROUND EAST KENTUCKY THROUGH THE NEXT SEVERAL HOURS WITH AN
DECENT POTENTIAL EVOLUTION OF STORMS INTO A LARGER SYSTEM LATER IN
THE FIRST PART OF THE EVENING SOMEWHERE TO THE NORTHWEST. THE
INGREDIENTS ARE THERE FOR ANOTHER ROUND OF SUCH STORMS AND THE
EXCESSIVE RAINFALL THEY PRODUCE. STILL THE BEST INDICATIONS ARE THAT
THE WORST OF ANY SUCH DEVELOPMENT WILL JUST BRUSH OUR SOUTHWESTERN
COUNTIES WHERE WE ARE NOT QUITE AS SATURATED AS THE EAST. THIS IS
GOOD NEWS...BUT GIVEN THE LOW FFG IN THE EAST JUST ABOUT ANY HEALTHY
STORM THERE WILL PROMPT FLASH FLOODING CONCERNS. WITH THE STILL HIGH
PWS AND INSTABILITY ACROSS THE ENTIRE AREA CANNOT CALL ANY PLACE FREE
OF LOCALIZED FLASH FLOOD CONCERNS. THE ACTIVITY IS EXPECTED TO DIE
DOWN LATER THIS EVENING AND WHEN COMBINED WITH AT LEAST PARTIAL
CLEARING WILL LIKELY BRING ABOUT ANOTHER BLANKET OF FOG BECOMING
DENSE IN AREAS TOWARD DAWN. WILL HIT THIS...IN ADDITION TO THE
STORM/FLOOD CONCERNS...HARD IN THE HWO. ONCE THE FOG BURNS OFF ON
SUNDAY...PARTLY SUNNY SKIES WILL AGAIN BUILD THE HEAT AND INSTABILITY
THROUGH THE AREA WHILE LOWER PWS FOR MUCH OF THE AREA WILL LIMIT TO A
SMALLER EXTENT FLASH FLOOD CONCERNS. EXPECT SOME COOLER AND...MORE
IMPORTANTLY...DRIER AIR TO MAKE IT INTO THE EAST BY EVENING AS A BACK
DOOR COLD FRONT PUSHES WEST THROUGH THE AREA ALLOWING SOME LOWS
CLOSER TO NORMAL FOR THIS TIME OF YEAR IN THE FAR EAST BY DAWN
MONDAY. AGAIN PATCHY FOG WILL BE A CONCERN DEPENDING ON THE RAINS
OF THE PREVIOUS DAY AND CLEARING THAT NIGHT.
STUCK WITH THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND SUNDAY
NIGHT. AS FOR POPS...ENDED UP CLOSER TO THE WETTER MET GUIDANCE
TONIGHT AND THEN NEARER THE MAV NUMBERS FOR THE REST OF THE SHORT
TERM PORTION OF THE FORECAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 239 PM EDT SAT AUG 23 2014
STRONG RIDGING WILL DOMINATE THE EASTERN CONUS THROUGH NEXT WEEK
WITH SUMMER-LIKE WEATHER CONTINUING. FORTUNATELY...WITH A STRONGER
CAP PRESENT...CONVECTION WILL BE HELD MORE AT BAY. CANNOT RULE OUT A
STRAY AFTERNOON SHOWER OR STORM EACH DAY...BUT SHOULD BE NOTHING
LIKE WE HAVE SEEN LATELY. PLANNING TO GO WITH A DIURNAL TREND WITH
POPS THROUGH THE END OF THE PERIOD WITH POPS PEAKING EACH AFTERNOON
WITH MAXIMUM HEATING/INSTABILITY. A SURFACE TROUGH MAY APPROACH FROM
THE WEST EARLY NEXT WEEKEND...BUT A TROPICAL SYSTEM DEVELOPING OVER
THE ATLANTIC BASIN...MAY HAVE A TENDENCY TO SLOW DOWN THE
ADVANCEMENT OF THIS FEATURE UNTIL SOMETIME LATE IN THE WEEKEND OR
THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 733 PM EDT SAT AUG 23 2014
BASED ON THE LATEST MODEL DATA AND RECENT TRENDS IN RADAR
IMAGERY...IT APPEARS THAT SHOWERS AND STORMS WILL NOT BE MUCH OF AN
ISSUE FOR THE TAF SITES. OVER THE PAST COUPLE OF HOURS WE HAVE SEEN
ISOLATED SHOWERS AND ACROSS EASTERN KENTUCKY AT BEST. WITH THE SUN
SETTING...THE ATMOSPHERE WILL COOL...FURTHER INHIBITING SHOWER AND
STORM FORMATION ACROSS THE AREA. THAT BEING SAID...HAVE INCLUDED A
VCTS IN THE PREVAILING CONDITIONS FOR LOZ AND SME...IN CASE ANY OF
THE STORMS CURRENTLY DRIFTING SOUTHWARD ACROSS EAST CENTRAL KENTUCKY
ARE ABLE TO MAKE THERE WAY INTO OUR SOUTHWESTERN COUNTIES. FOG
FORMATION OVERNIGHT WILL BE THE PRIMARY CONCERN. IT APPEARS THE FIRST
WISPS OF FOG WILL BEGIN TO FORM BETWEEN 5 AND 6Z...WITH THE MOST
WIDESPREAD FOG OCCURRING BETWEEN 9 AND 12Z ON SUNDAY. WITH CONDITIONS
RIPE FOR IT...THE TAF SITES ALL HAVE A GOOD CHANCE OF EXPERIENCING
IFR TO VLIFR CONDITIONS AS DENSE FOG OVERSPREADS THE AREA. THE FOG
WILL BEGIN BURNING OFF AROUND 8 AM AND SHOULD BE COMPLETELY GONE BY
BETWEEN 9 AND 10 AM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
733 PM EDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 733 PM EDT SAT AUG 23 2014
WILL BE SENDING OUT AND UPDATED ZONE FORECAST SHORTLY TO REMOVE THE
PRE FIRST PERIOD PUT IN BY THE DAY SHIFT AND TO DECREASE PRECIPITATION
CHANCES CROSS THE ENTIRE AREA FOR THE REMAINDER OF THE OVERNIGHT
PERIOD INTO EARLY TOMORROW MORNING. THE LATEST NAM12 AND HRRR MODEL
RUNS MATCH UP WELL WITH THE ISOLATED SHOWER AND STORM COVERAGE
CURRENTLY BEING OBSERVED ACROSS EASTERN KENTUCKY. BASED ON THE THE
FACT THAT MOST OF THE LONG LIVED SHOWERS AND STORMS ARE CONFINED TO
CENTRAL KENTUCKY AND WITH THEIR SLOW SOUTHWARD DIRECTION OF
MOVEMENT...AND WITH THE SUN DUE TO SET SOON...IT SIMPLY DOES NOT
APPEAR THAT WE WILL SEE MORE THAN ISOLATED SHOWERS OR STORMS ACROSS
THE MAJORITY OF THE AREA TONIGHT. THERE STILL IS A SMALL CHANCE OF
SCATTERED ACTIVITY WEST OF I75...BUT EVEN THAT IS IN QUESTION AT THIS
POINT. THE FOG FORMATION OVERNIGHT IS ON TRACK...HOWEVER...WITH CLEAR
SKIES...LIGHT WINDS...AND AMPLE SURFACE MOISTURE IN PLACE. WE WILL
STILL LIKELY SEE AREAS OF DENSE FOG LATE TONIGHT INTO EARLY TOMORROW
MORNING...WITH THE MOST FAVORED AREAS BEING OUR VALLEYS. THE NEW
FORECAST WILL REFLECT MUCH LOWER PRECIPITATION CHANCES OVERNIGHT AND
WIDESPREAD FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 350 PM EDT SAT AUG 23 2014
19Z SFC ANALYSIS SHOWS OUR CONTINUING WEATHER CHALLENGE WITH THE LOW
PRESSURE OUT TO THE WEST AND HIGH PRESSURE TO THE SOUTH. A WAVY
NORTHWEST TO SOUTHEAST FRONT EXISTS JUST NORTH OF OUR AREA.
MEANWHILE...ALOFT...A RIDGE IS FOUND THROUGH THE LOWER MIDSECTION OF
THE NATION WITH A DIGGING TROUGH MOVING INTO THE MID ATLANTIC STATES.
THIS PLACES CENTRAL AND EASTERN KENTUCKY IN THE TRACK OF ENERGY
MOVING FROM THE UPPER MIDWEST INTO THE SOUTHERN APPALACHIANS TODAY.
THESE FEATURES HAVE BEEN COMBINING LATELY TO PRODUCE CLUSTERS OF
SHOWERS AND THUNDERSTORMS GENERALLY STARTING IN THE LATE AFTERNOON
AND LASTING INTO THE EVENING. THE HIGH PW AIR IN PLACE OVER THE
AREA...ALONG WITH THE DEWPOINTS PUSHING THE MID 70S...MAKES FOR
PROLIFIC RAIN PRODUCING CELLS. AS HAS BEEN THE CASE REMAINS SO
HEADING INTO LATE AFTERNOON...THOUGH THE AXIS OF CONCERN HAS SHIFTED
SLIGHTLY WEST OWING TO THE WIGGLE OF THE RIDGE IN RESPONSE TO THE
DIGGING TROUGH. CURRENTLY SCATTERED AND ISOLATED SHOWERS/STORMS ARE
DOTTING THE CUMBERLAND VALLEY WITH SIGNS OF LARGER CLUSTERS STARTING
TO TAKE SHAPE TO THE NORTHWEST. THOUGH DELAYED A BIT BY THE LOW
STRATUS DECK FOLLOWING THE DENSE FOG THIS MORNING...TEMPERATURES HAVE
CLIMBED SMARTLY INTO THE MIDDLE AND UPPER 80S THROUGH THE AREA AND
WITH SUCH HIGH DEWPOINTS ARE YIELDING HEAT INDICES IN THE 95 TO 100
DEGREE RANGE. WINDS HAVE BEEN MAINLY LIGHT AND VARIABLE THROUGH THE
AREA.
THE MODELS ARE ALL IN PRETTY GOOD AGREEMENT ALOFT WITH THE WIGGLE
WEST AND THEN BACK EAST OF THE UPPER RIDGE INTO MONDAY MORNING.
SHORTWAVE ENERGY MOVING SOUTH BETWEEN THE UPPER SYSTEMS WILL PASS
THROUGH CENTRAL AND EASTERN KENTUCKY TONIGHT WITH ONLY WEAKER PACKETS
FORESEEN THROUGH THE REST OF THE WEEKEND. GIVEN THE AGREEMENT OF THE
MODELS AND THE SMALLER SCALE NATURE OF CONVECTIVE ACTIVITY OF THIS
REGIME HAVE AGAIN FAVORED THE HRRR AND NAM12 THROUGH THE FIRST 18 TO
36 HOURS AND A MODEL CONSENSUS AFTER THAT INTO MONDAY MORNING.
SENSIBLE WEATHER WILL FEATURE ISOLATED AND SCATTERED CONVECTION
AROUND EAST KENTUCKY THROUGH THE NEXT SEVERAL HOURS WITH AN
DECENT POTENTIAL EVOLUTION OF STORMS INTO A LARGER SYSTEM LATER IN
THE FIRST PART OF THE EVENING SOMEWHERE TO THE NORTHWEST. THE
INGREDIENTS ARE THERE FOR ANOTHER ROUND OF SUCH STORMS AND THE
EXCESSIVE RAINFALL THEY PRODUCE. STILL THE BEST INDICATIONS ARE THAT
THE WORST OF ANY SUCH DEVELOPMENT WILL JUST BRUSH OUR SOUTHWESTERN
COUNTIES WHERE WE ARE NOT QUITE AS SATURATED AS THE EAST. THIS IS
GOOD NEWS...BUT GIVEN THE LOW FFG IN THE EAST JUST ABOUT ANY HEALTHY
STORM THERE WILL PROMPT FLASH FLOODING CONCERNS. WITH THE STILL HIGH
PWS AND INSTABILITY ACROSS THE ENTIRE AREA CANNOT CALL ANY PLACE FREE
OF LOCALIZED FLASH FLOOD CONCERNS. THE ACTIVITY IS EXPECTED TO DIE
DOWN LATER THIS EVENING AND WHEN COMBINED WITH AT LEAST PARTIAL
CLEARING WILL LIKELY BRING ABOUT ANOTHER BLANKET OF FOG BECOMING
DENSE IN AREAS TOWARD DAWN. WILL HIT THIS...IN ADDITION TO THE
STORM/FLOOD CONCERNS...HARD IN THE HWO. ONCE THE FOG BURNS OFF ON
SUNDAY...PARTLY SUNNY SKIES WILL AGAIN BUILD THE HEAT AND INSTABILITY
THROUGH THE AREA WHILE LOWER PWS FOR MUCH OF THE AREA WILL LIMIT TO A
SMALLER EXTENT FLASH FLOOD CONCERNS. EXPECT SOME COOLER AND...MORE
IMPORTANTLY...DRIER AIR TO MAKE IT INTO THE EAST BY EVENING AS A BACK
DOOR COLD FRONT PUSHES WEST THROUGH THE AREA ALLOWING SOME LOWS
CLOSER TO NORMAL FOR THIS TIME OF YEAR IN THE FAR EAST BY DAWN
MONDAY. AGAIN PATCHY FOG WILL BE A CONCERN DEPENDING ON THE RAINS
OF THE PREVIOUS DAY AND CLEARING THAT NIGHT.
STUCK WITH THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND SUNDAY
NIGHT. AS FOR POPS...ENDED UP CLOSER TO THE WETTER MET GUIDANCE
TONIGHT AND THEN NEARER THE MAV NUMBERS FOR THE REST OF THE SHORT
TERM PORTION OF THE FORECAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 239 PM EDT SAT AUG 23 2014
STRONG RIDGING WILL DOMINATE THE EASTERN CONUS THROUGH NEXT WEEK
WITH SUMMER-LIKE WEATHER CONTINUING. FORTUNATELY...WITH A STRONGER
CAP PRESENT...CONVECTION WILL BE HELD MORE AT BAY. CANNOT RULE OUT A
STRAY AFTERNOON SHOWER OR STORM EACH DAY...BUT SHOULD BE NOTHING
LIKE WE HAVE SEEN LATELY. PLANNING TO GO WITH A DIURNAL TREND WITH
POPS THROUGH THE END OF THE PERIOD WITH POPS PEAKING EACH AFTERNOON
WITH MAXIMUM HEATING/INSTABILITY. A SURFACE TROUGH MAY APPROACH FROM
THE WEST EARLY NEXT WEEKEND...BUT A TROPICAL SYSTEM DEVELOPING OVER
THE ATLANTIC BASIN...MAY HAVE A TENDENCY TO SLOW DOWN THE
ADVANCEMENT OF THIS FEATURE UNTIL SOMETIME LATE IN THE WEEKEND OR
THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 733 PM EDT SAT AUG 23 2014
BASED ON THE LATEST MODEL DATA AND RECENT TRENDS IN RADAR
IMAGERY...IT APPEARS THAT SHOWERS AND STORMS WILL NOT BE MUCH OF AN
ISSUE FOR THE TAF SITES. OVER THE PAST COUPLE OF HOURS WE HAVE SEEN
ISOLATED SHOWERS AND ACROSS EASTERN KENTUCKY AT BEST. WITH THE SUN
SETTING...THE ATMOSPHERE WILL COOL...FURTHER INHIBITING SHOWER AND
STORM FORMATION ACROSS THE AREA. THAT BEING SAID...HAVE INCLUDED A
VCTS IN THE PREVAILING CONDITIONS FOR LOZ AND SME...IN CASE ANY OF
THE STORMS CURRENTLY DRIFTING SOUTHWARD ACROSS EAST CENTRAL KENTUCKY
ARE ABLE TO MAKE THERE WAY INTO OUR SOUTHWESTERN COUNTIES. FOG
FORMATION OVERNIGHT WILL BE THE PRIMARY CONCERN. IT APPEARS THE FIRST
WISPS OF FOG WILL BEGIN TO FORM BETWEEN 5 AND 6Z...WITH THE MOST
WIDESPREAD FOG OCCURRING BETWEEN 9 AND 12Z ON SUNDAY. WITH CONDITIONS
RIPE FOR IT...THE TAF SITES ALL HAVE A GOOD CHANCE OF EXPERIENCING
IFR TO VLIFR CONDITIONS AS DENSE FOG OVERSPREADS THE AREA. THE FOG
WILL BEGIN BURNING OFF AROUND 8 AM AND SHOULD BE COMPLETELY GONE BY
BETWEEN 9 AND 10 AM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...AR
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 PM EDT FRI AUG 22 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 335 PM EDT FRI AUG 22 2014
18Z SFC ANALYSIS SHOWS A CONVECTIVELY WASHED OUT BOUNDARY JUST NORTH
OF THE OHIO RIVER. THIS LEADS BACK WEST TO A DEVELOPING AREA OF LOW
PRESSURE OVER THE HIGH PLAINS. MEANWHILE...AN AREA OF HIGH PRESSURE
IS FOUND THROUGH THE DEEP SOUTH. ALOFT...A FAIRLY STRONG RIDGE OF
HIGH HEIGHTS STRETCHES FROM THE SOUTHERN PLAINS THROUGH THE LOWER
MISSISSIPPI RIVER VALLEY AND ACROSS THE DEEP SOUTH WHILE TROUGHING
IS FOUND OVER NEW ENGLAND. BETWEEN THESE UPPER LEVEL FEATURES...A
COUPLE OF SHORTWAVES ARE PASSING BY TO THE NORTHEAST. THE LEADING ONE
OF THESE IS RESPONSIBLE FOR BETTER DEVELOPMENT OF CONVECTION OVER FAR
EASTERN KENTUCKY AND WESTERN WEST VIRGINIA. ELSEWHERE...TO THE WEST
OF THIS AREA...A FEW SCATTERED SHOWERS AND THUNDERSTORMS ARE TAKING
SHAPE ALONG AN OLD OUTFLOW BOUNDARY FROM THE PRE DAWN MCS THAT MOVED
THROUGH OHIO EARLY THIS MORNING. WITH THE BULK OF THE ACTIVITY
HOLDING OFF UNTIL LATER IN THE AFTERNOON...TEMPERATURES HAVE CLIMBED
INTO THE UPPER 80S FOR MOST LOCATIONS WITH A FEW 90 DEGREE READINGS
NOTED. DEWPOINTS IN THE LOWER AND MIDDLE 70S ARE MAKING FOR MISERABLE
HEAT INDICES THROUGH THE AREA AND WILL BE PROVIDING FUEL FOR STORM
DEVELOPMENT. WINDS ARE GENERALLY FROM THE WEST SOUTHWEST AT 5 TO 10
KTS WITH A FEW GUSTS TO 15 KTS.
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM ALOFT AS THEY
ALL WOBBLE AND WEAKEN SLIGHTLY THE RIDGE TO OUR WEST IN THE FACE OF
THE NEW ENGLAND TROUGH DROPPING NEARLY DUE SOUTH TO THE MID ATLANTIC
COAST BY SUNDAY MORNING. DESPITE THE MOVEMENT OF THESE LARGER
FEATURES...THE TRACK OF SHORTWAVES WILL CONTINUE TO PASS THROUGH FAR
EASTERN KENTUCKY...JUST ORIENTATED MORE NORTH TO SOUTH BY THE END OF
THE PERIOD. GIVEN THE MODEL AGREEMENT AND THE SMALLER SCALE NATURE OF
THE PERIODIC MCS ACTIVITY HAVE FAVORED THE HIGHER RESOLUTION MODELS
LIKE THE HRRR AND NAM12 FOR THIS FORECAST.
SENSIBLE WEATHER WILL FEATURE A THREAT OF STORMS INTO THE EVENING...
PERHAPS LENGTHENED BY ANY DEVELOPMENT TO THE NORTHWEST THAT COULD
MOVE INTO AT LEAST THE NORTHWEST PORTION OF THE JKL CWA AFTER DARK...
PER THE LATEST HRRR. SIMILAR TO LAST EVENING...THE MAIN THREATS
WITH ANY STORMS WILL BE GUSTY WINDS AND TORRENTIAL DOWNPOURS OF RAIN.
AGAIN TONIGHT...WOULD ANTICIPATE PATCHY FOG THROUGH THE AREA AND THE
POTENTIAL FOR DENSE SPOTS LOCALLY GIVEN ANY CLEARING. AFTER A MUGGY
NIGHT...ANOTHER WARM AND HUMID DAY CAN BE EXPECTED FOR SATURDAY WITH
MID LEVEL CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH THE ENTIRETY
WITH ONLY A SLIGHT FAVORING OF THE LATE AFTERNOON AND EARLY EVENING
HOURS. HIGH PWS AND INSTABILITY DURING THE DAY WILL SET THE TABLE FOR
A CONTINUED THREAT OF EXCESSIVE RAINFALL AND STRONG STORMS...THOUGH
THE SEVERE RISK WILL BE LIMITED BY A GENERALLY BENIGN NORTHWEST WIND
FIELD ALOFT. SIMILARLY...SATURDAY NIGHT WILL BE ANOTHER MUGGY AND
WARM ONE WITH PATCHY FOG ANTICIPATED FOR PLACES THAT WOULD HAVE SEEN
RAIN DURING THE DAY. CANNOT RULE OUT ADDITIONAL SHOWER AND STORM
ACTIVITY INTO EARLY SUNDAY GIVEN THE UPPER LEVEL PATTERN AND NEARBY
SFC BOUNDARIES.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND SATURDAY
NIGHT. AS FOR POPS...ENDED UP IN BETWEEN THE MAV AND THE WETTER MET
GUIDANCE FOR MOST OF THE SHORT TERM PORTION OF THE FORECAST.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 255 PM EDT FRI AUG 22 2014
STRONG RIDGING WILL CONTINUE TO DEVELOP OVER THE EASTERN CONUS LATE
IN THE WEEKEND THROUGH THE EARLY PART OF NEXT WEEK. AS THE CENTER OF
THE HIGH PUSHES OVERHEAD EARLY NEXT WEEK...IT WILL SEND SOME
SLIGHTLY DRIER AIR INTO EASTERN KENTUCKY...FINALLY BRINGING A
TEMPORARY END TO THE RAIN CHANCES. HAVE BEEN GOING WITH LOW POPS
EARLY NEXT WEEK...BUT GIVEN THE NATURE OF THE DRY AIR...HAVE OPTED
TO GO WITH DRY WEATHER EARLY TO MIDDLE PART OF NEXT WEEK. IN
FACT...DEWPOINTS MAY GET LOW ENOUGH TO WARRANT A FEW TEMPERATURES
INTO THE LOWER AND MIDDLE 60S TUESDAY AND WEDNESDAY MORNINGS. CANNOT
RULE OUT SOME SHOWERS ON SUNDAY OR SUNDAY EVENING PRIOR TO THE
DEPARTURE OF THE BETTER MID LEVEL MOISTURE. HOWEVER...EVEN THIS
ACTIVITY WILL LIKELY BE LESS THAN WHAT WE HAVE SEEN RECENTLY.
THUS...OVERALL...LOOK FOR A QUIETER STRETCH OF WEATHER INTO THE
MIDDLE OF NEXT WEEK. BY LATE IN THE PERIOD. THE RIDGE MAY BEGIN TO
BREAK DOWN AS A SHORTWAVE TROUGH MOVING ACROSS THE GREAT LAKES
PUSHES A BOUNDARY SOUTHWARD INTO THE OHIO RIVER VALLEY. TOO MUCH
UNCERTAINTY WITH THIS BOUNDARY TO GO WITH ANYTHING MORE THAN CHANCE
POPS FROM THURSDAY ONWARD. THE 00Z ECMWF HAD PUT THE BOUNDARY OVER
EASTERN KENTUCKY...BUT THE 12Z RUN HAS KEPT IT TO THE NORTH THROUGH
WEEKS END. IF THE BOUNDARY STAYS NORTH...PROBABLY GOING TO SEE
WARMER AND HUMID CONDITIONS PERSISTING THROUGH THE SECOND HALF OF
NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 200 PM EDT FRI AUG 22 2014
STILL AWAITING DEVELOPMENT OF STORMS THROUGH EAST KENTUCKY THIS
AFTERNOON. WITHOUT A CLEAR INDICATION OF WHERE THEY WILL BE POPPING
AND AFFECTING THE TAF SITES HAVE LEFT THEM WITH VCTS THROUGH THE REST
OF THE DAY AND INTO THE EVENING BEFORE BACKING OFF TO JUST SOME VCSH
AND LIGHT FOG LATER TONIGHT. WITH THE HIGH LEVEL OF MOISTURE OUT
THERE SOME OF THE DECKS OF CLOUDS HAVE COME IN RATHER LOW FOR THE
MIDDLE OF THE DAY...ESPECIALLY IN THE NORTHEAST PARTS OF THE AREA.
EXPECT THIS TO BE THE CASE INTERMITTENTLY THROUGH THE FIRST PART OF
THE EVENING AND ALSO WITH ANY STORM...HOWEVER...MUCH OF THE TIME AT
THE SITES CIGS WILL BE VFR IF THERE AT ALL. A SIMILAR SET UP FOR
TOMORROW WILL CONTINUE THE THREAT OF SHOWERS AND STORMS THROUGH THE
DAY WITH A POTENTIAL FOR MVFR CIGS AND VIS WITH ANY CONVECTION. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE EXPECT DURING PEAK
HEATING WHEN SOME MAINLY WESTERLY BREEZES WILL TOP OUT BETWEEN 5 AND
10 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
200 PM EDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 140 PM EDT FRI AUG 22 2014
STORMS ARE STARTING TO POP OVER WESTERN WEST VIRGINIA IN ADDITION TO
HINTS THAT SOME ARE STARTING TO FORM ALONG A WELL DEFINED OUTFLOW
BOUNDARY DRIFTING SOUTH THROUGH CENTRAL AND PARTS OF EASTERN
KENTUCKY. THE RAP MODEL IS STILL ON TRACK WITH EXPECTED DEVELOPMENTS
OVER NORTHEASTERN PARTS OF THE AREA BUILDING SOUTH WITH TIME. HAVE
MADE ONLY MINOR ADJUSTMENTS TO THE EXISTING FORECAST...PRIMARILY TO
FINE TUNE POPS AND SKY COVER OVER THE NEXT FEW HOURS...IN ADDITION TO
TWEAKING TEMPS AND DEWPOINTS PER THE LATEST OBS AND TRENDS. THESE
FRESHENED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1200 PM EDT FRI AUG 22 2014
15Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE THROUGH THE DEEP SOUTH WITH
GENERAL LOW PRESSURE TO THE NORTH AND WEST OF THIS AREA. THIS PLACES
EAST KENTUCKY ON THE NORTHERN FRINGE OF THE SFC RIDGE AND ALSO THE
NORTHEAST EDGE OF THE MID LEVEL ONE PARKED TO THE SOUTHWEST OF THE
AREA. THE STORM TRACK...LIKE THOSE PAST COUPLE OF DAYS...IS PRETTY
CLEAR AS CONVECTIVE CLUSTERS DEVELOP IN NORTHERN ILLINOIS AND
INDIANA...ROLLING SOUTHEAST INTO OHIO BEFORE HITTING THE APPALACHIANS
AT WEST VIRGINIA. THE BEST INSTABILITY REMAINS TO THE SOUTH AND WEST
OF THIS TRACK...LEADING TO A TENDENCY FOR THESE SYSTEMS TO ARC TO THE
SOUTH INTO EASTERN KENTUCKY OR KICKING OFF OUTFLOW BOUNDARIES STRONG
ENOUGH TO INITIATE NEW DEVELOPMENT. THE LATEST HIGH RESOLUTION NEAR
TERM MODELS INCLUDING THE HRRR AND 12Z NAM12 SUGGEST THAT BOTH
SCENARIOS ARE POSSIBLE THIS AFTERNOON WITH THE FORMER FOCUSING ON
SCATTERED DEVELOPMENT THROUGH THE CWA AFTER 18Z AND PERHAPS A MORE
ORGANIZED SYSTEM ARRIVING FROM THE NORTHWEST AFTER 21Z. THE NAM12
FOCUSES ON THE NORTHWEST SYSTEM AND HAS IT PUSH INTO EAST KENTUCKY
BETWEEN 18 AND 21Z WITH LESS AIR MASS CONVECTION AHEAD OF IT.
ALOFT...THE GENESIS WAVE APPEARS TO PASS THROUGH THE SOUTHERN OHIO
VALLEY BY 21Z SO THE NAM12 WITH ITS EARLIER ARRIVAL APPEARS TO BE
REASONABLE. HIGH PWS AGAIN TODAY ALONG WITH GOOD INSTABILITY SUGGEST
THE POTENTIAL FOR FLASH FLOODING...ESPECIALLY FOR PLACES THAT SEE
TRAINING...ALONG WITH STRONG TO MARGINALLY SEVERE STORMS WITH
DAMAGING WIND GUSTS AS THE MAIN THREAT. HAVE UPDATED TO CONVEY THIS
IN THE SKY...POP...QPF...AND WX GRIDS. EAST KENTUCKY WILL ALSO HAVE A
CONTINUANCE OF THE HOT AND HUMID CONDITIONS WITH HIGHS AROUND
90...SUBJECT TO THUNDERSTORM INDUCED COOL DOWNS...AND DEWPOINTS IN
THE STEAMY LOW TO MID 70S. A NEW SET OF ZONES WERE ISSUED TO REFLECT
THE ABOVE AND THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS.
UPDATE ISSUED AT 810 AM EDT FRI AUG 22 2014
THE FORECAST REMAINS ON TRACK THIS MORNING. SHOWERS AND THUNDERSTORMS
WILL LIKELY STEER CLEAR OF THE AREA UNTIL MAINLY THIS AFTERNOON.
FRESHENED UP THE SKY COVER AND HOURLY TEMPERATURES AND DEW POINTS TO
ALIGN BETTER WITH THE LATEST TRENDS IN OBSERVATIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 400 AM EDT FRI AUG 22 2014
THE LATEST SURFACE MAP FEATURES SURFACE HIGH PRESSURE ACROSS THE GULF
COAST STATES...WITH BROADENING LOW PRESSURE ACROSS THE PLAINS. A
STATIONARY FRONTAL BOUNDARY EXTENDS EAST FROM THE PLAINS INTO THE
GREAT LAKES/OHIO VALLEY. ALOFT...AN UPPER LEVEL RIDGE IS CURRENTLY
CENTERED NEAR LOUISIANA WITH ITS INFLUENCE EXTENDING FURTHER NORTH
INTO THE MISSISSIPPI VALLEY. TROUGHING REMAINS POISED ACROSS THE
WESTERN CONUS.
THUNDERSTORM COMPLEXES CONTINUE TO GEN UP ON THE NORTHERN PERIPHERY
OF THE RIDGE AXIS AND THEN PROCEED TO ADVANCE ESE ACROSS THE OHIO
VALLEY. CURRENTLY...A WEAKENING COMPLEX IS SKIRTING NORTHEASTERN
KENTUCKY...LIKELY CLEARING OUR FORECAST AREA IN THE NEXT 2 TO 3
HOURS.
THE MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM...WITH THE
UPPER LEVEL RIDGE GRADUALLY AMPLIFYING ACROSS THE MISSISSIPPI VALLEY.
DETAILS ASSOCIATED WITH CONVECTIVE INITIATION CONTINUE TO BE
PROBLEMATIC HOWEVER...AND HAVE STUCK WITH A GENERAL MODEL
BLEND...WHICH FAVORS MORE VIGOROUS CONVECTION DURING THE WARMER PART
OF THE DAY. TODAY LOOKS TO BE SOMEWHAT OF A REPEAT OF
YESTERDAY...WITH STOUT INSTABILITY BUILDING BY EARLY THIS AFTERNOON.
WHILE THE MCS TRACK HAS SHIFTED A BIT FURTHER NORTHEAST TODAY
COMPARED TO YESTERDAY...OUTFLOW BOUNDARIES CONTINUE TO BE THE MAIN
PLAYER...LEAVING MOST LOCATIONS IN THE LINE OF FIRE AT SOME POINT.
SOME SEVERE THUNDERSTORMS CAN NOT BE RULED OUT ONCE AGAIN
TODAY...ALONG WITH ISOLATED FLASH FLOODING...WHERE STORMS CAN ALIGN
ALONG OUTFLOW BOUNDARIES PARALLEL TO THE STEERING FLOW. ANOTHER HOT
AND HUMID DAY LOOKS TO BE ON TAP...WITH A FEW SPOTS NEARING THE 100
DEGREE MARK IN HEAT INDICES.
STORMS WILL GRADUALLY WEAKEN INTO THE EVENING HOURS...ALTHOUGH SOME
NOCTURNAL ACTIVITY REMAINS AT LEAST SOMEWHAT OF A POSSIBILITY. LOWS
WILL BE MUGGY ONCE AGAIN AROUND THE 70 DEGREE MARK. SATURDAY WILL
FEATURE ANOTHER WARM AND HUMID DAY...ALONG WITH THE THREAT OF MORE
SCATTERED CONVECTION ACROSS THE AREA. THERE WILL BE LESS INSTABILITY
AVAILABLE AS MID-LEVEL WARMING TAKES PLACE FROM THE INFLUENCE OF THE
UPPER RIDGE. THIS WILL KEEP THE SEVERE AND FLASH FLOOD THREAT LOWER.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM EDT FRI AUG 22 2014
UPPER LEVEL RIDGING WILL REMAIN IN PLAY DURING THE DURATION OF THE
EXTENDED...WITH HEIGHTS EXPECTED TO BUILD AS THE HIGH SHIFTS NEWARD
ACROSS THE OHIO RIVER VALLEY. BUILDING HEIGHTS WILL THEN TRANSLATE
TO RISING TEMPERATURES. HOWEVER...MID AND UPPER LEVEL WINDS WILL
GENERALLY REMAIN OUT OF THE NORTH DURING THE FIRST FEW DAYS OF THE
EXTENDED. THIS...COUPLED WITH CLOUD COVER THAT WILL HAMPER MAXIMUM
SOLAR RADIATION...WILL KEEP HIGHS IN THE MID AND UPPER 80S THROUGH
TUESDAY. TEMPS MAY THEN COOL DOWN A COUPLE DEGREES AFTER TUESDAY AS
HIGH PRESSURE SITS OVERHEAD AND UPPER LEVEL HEIGHTS ASSOCIATED WITH
THE RIDGE BECOME MORE STATIC.
BASED ON THE LATEST FORECAST SOUNDINGS...WILL AGREE WITH PREVIOUS
FORECAST THAT EACH DAY SHOULD POSE A SHOWER/THUNDERSTORM THREAT
MAINLY IN THE AFTERNOON AND EVENING. GIVEN THE MID LEVEL DRYING FROM
MONDAY ON...WOULDN/T BE SURPRISED IF SOME OF THESE STORMS PRODUCE
SOME POTENTIAL HAIL. IN PROMISING NEWS...WITH THE RIDGING PATTERN IN
PLACE...WE WILL EXPERIENCE NO BOUNDARY FORCING UNTIL VERY LATE IN THE
FORECAST...SO THIS WILL HAMPER SOME OF THE BEST INSTABILITY AND
WIDESPREAD INITIATION. WINDS WILL BE LIGHT AT THE SURFACE...AND
REMAIN SO AS WE HEAD UP HIGHER INTO THE ATMOSPHERE. THAT BEING
SAID...AFTERNOON CAPE VALUES WILL BE ABOVE THE 2K J/KG RANGE THROUGH
MUCH OF THE EXTENDED...AND LAPSE RATES WILL RISE SLIGHTLY BY TUES/WED
TO 6 TO 6.5 C/KM...SO AFTERNOON HEATING AND INSTABILITY MAY BE ALL
THAT IS NECESSARY FOR SCATTERED CELL DEVELOPMENT EACH DAY. A BOUNDARY
WILL FINALLY PUSH INTO THE AREA BY THURS/FRI DAY 7/8 /PER THE LATEST
GFS MODEL RUN/. THIS WILL BRING A MORE WIDESPREAD CHANCE FOR RAIN AND
THUNDERSTORMS ACROSS THE AREA. HOWEVER...THERE IS QUITE A BIT OF
DISAGREEMENT IN THE EXTENDED MODELS THIS FAR OUT...SO DECIDED TO LEAN
ON THE ALLBLEND FOR POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 200 PM EDT FRI AUG 22 2014
STILL AWAITING DEVELOPMENT OF STORMS THROUGH EAST KENTUCKY THIS
AFTERNOON. WITHOUT A CLEAR INDICATION OF WHERE THEY WILL BE POPPING
AND AFFECTING THE TAF SITES HAVE LEFT THEM WITH VCTS THROUGH THE REST
OF THE DAY AND INTO THE EVENING BEFORE BACKING OFF TO JUST SOME VCSH
AND LIGHT FOG LATER TONIGHT. WITH THE HIGH LEVEL OF MOISTURE OUT
THERE SOME OF THE DECKS OF CLOUDS HAVE COME IN RATHER LOW FOR THE
MIDDLE OF THE DAY...ESPECIALLY IN THE NORTHEAST PARTS OF THE AREA.
EXPECT THIS TO BE THE CASE INTERMITTENTLY THROUGH THE FIRST PART OF
THE EVENING AND ALSO WITH ANY STORM...HOWEVER...MUCH OF THE TIME AT
THE SITES CIGS WILL BE VFR IF THERE AT ALL. A SIMILAR SET UP FOR
TOMORROW WILL CONTINUE THE THREAT OF SHOWERS AND STORMS THROUGH THE
DAY WITH A POTENTIAL FOR MVFR CIGS AND VIS WITH ANY CONVECTION. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE EXPECT DURING PEAK
HEATING WHEN SOME MAINLY WESTERLY BREEZES WILL TOP OUT BETWEEN 5 AND
10 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1200 PM EDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 1200 PM EDT FRI AUG 22 2014
15Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE THROUGH THE DEEP SOUTH WITH
GENERAL LOW PRESSURE TO THE NORTH AND WEST OF THIS AREA. THIS PLACES
EAST KENTUCKY ON THE NORTHERN FRINGE OF THE SFC RIDGE AND ALSO THE
NORTHEAST EDGE OF THE MID LEVEL ONE PARKED TO THE SOUTHWEST OF THE
AREA. THE STORM TRACK...LIKE THOSE PAST COUPLE OF DAYS...IS PRETTY
CLEAR AS CONVECTIVE CLUSTERS DEVELOP IN NORTHERN ILLINOIS AND
INDIANA...ROLLING SOUTHEAST INTO OHIO BEFORE HITTING THE APPALACHIANS
AT WEST VIRGINIA. THE BEST INSTABILITY REMAINS TO THE SOUTH AND WEST
OF THIS TRACK...LEADING TO A TENDENCY FOR THESE SYSTEMS TO ARC TO THE
SOUTH INTO EASTERN KENTUCKY OR KICKING OFF OUTFLOW BOUNDARIES STRONG
ENOUGH TO INITIATE NEW DEVELOPMENT. THE LATEST HIGH RESOLUTION NEAR
TERM MODELS INCLUDING THE HRRR AND 12Z NAM12 SUGGEST THAT BOTH
SCENARIOS ARE POSSIBLE THIS AFTERNOON WITH THE FORMER FOCUSING ON
SCATTERED DEVELOPMENT THROUGH THE CWA AFTER 18Z AND PERHAPS A MORE
ORGANIZED SYSTEM ARRIVING FROM THE NORTHWEST AFTER 21Z. THE NAM12
FOCUSES ON THE NORTHWEST SYSTEM AND HAS IT PUSH INTO EAST KENTUCKY
BETWEEN 18 AND 21Z WITH LESS AIR MASS CONVECTION AHEAD OF IT.
ALOFT...THE GENESIS WAVE APPEARS TO PASS THROUGH THE SOUTHERN OHIO
VALLEY BY 21Z SO THE NAM12 WITH ITS EARLIER ARRIVAL APPEARS TO BE
REASONABLE. HIGH PWS AGAIN TODAY ALONG WITH GOOD INSTABILITY SUGGEST
THE POTENTIAL FOR FLASH FLOODING...ESPECIALLY FOR PLACES THAT SEE
TRAINING...ALONG WITH STRONG TO MARGINALLY SEVERE STORMS WITH
DAMAGING WIND GUSTS AS THE MAIN THREAT. HAVE UPDATED TO CONVEY THIS
IN THE SKY...POP...QPF...AND WX GRIDS. EAST KENTUCKY WILL ALSO HAVE A
CONTINUANCE OF THE HOT AND HUMID CONDITIONS WITH HIGHS AROUND
90...SUBJECT TO THUNDERSTORM INDUCED COOL DOWNS...AND DEWPOINTS IN
THE STEAMY LOW TO MID 70S. A NEW SET OF ZONES WERE ISSUED TO REFLECT
THE ABOVE AND THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS.
UPDATE ISSUED AT 810 AM EDT FRI AUG 22 2014
THE FORECAST REMAINS ON TRACK THIS MORNING. SHOWERS AND THUNDERSTORMS
WILL LIKELY STEER CLEAR OF THE AREA UNTIL MAINLY THIS AFTERNOON.
FRESHENED UP THE SKY COVER AND HOURLY TEMPERATURES AND DEW POINTS TO
ALIGN BETTER WITH THE LATEST TRENDS IN OBSERVATIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 400 AM EDT FRI AUG 22 2014
THE LATEST SURFACE MAP FEATURES SURFACE HIGH PRESSURE ACROSS THE GULF
COAST STATES...WITH BROADENING LOW PRESSURE ACROSS THE PLAINS. A
STATIONARY FRONTAL BOUNDARY EXTENDS EAST FROM THE PLAINS INTO THE
GREAT LAKES/OHIO VALLEY. ALOFT...AN UPPER LEVEL RIDGE IS CURRENTLY
CENTERED NEAR LOUISIANA WITH ITS INFLUENCE EXTENDING FURTHER NORTH
INTO THE MISSISSIPPI VALLEY. TROUGHING REMAINS POISED ACROSS THE
WESTERN CONUS.
THUNDERSTORM COMPLEXES CONTINUE TO GEN UP ON THE NORTHERN PERIPHERY
OF THE RIDGE AXIS AND THEN PROCEED TO ADVANCE ESE ACROSS THE OHIO
VALLEY. CURRENTLY...A WEAKENING COMPLEX IS SKIRTING NORTHEASTERN
KENTUCKY...LIKELY CLEARING OUR FORECAST AREA IN THE NEXT 2 TO 3
HOURS.
THE MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM...WITH THE
UPPER LEVEL RIDGE GRADUALLY AMPLIFYING ACROSS THE MISSISSIPPI VALLEY.
DETAILS ASSOCIATED WITH CONVECTIVE INITIATION CONTINUE TO BE
PROBLEMATIC HOWEVER...AND HAVE STUCK WITH A GENERAL MODEL
BLEND...WHICH FAVORS MORE VIGOROUS CONVECTION DURING THE WARMER PART
OF THE DAY. TODAY LOOKS TO BE SOMEWHAT OF A REPEAT OF
YESTERDAY...WITH STOUT INSTABILITY BUILDING BY EARLY THIS AFTERNOON.
WHILE THE MCS TRACK HAS SHIFTED A BIT FURTHER NORTHEAST TODAY
COMPARED TO YESTERDAY...OUTFLOW BOUNDARIES CONTINUE TO BE THE MAIN
PLAYER...LEAVING MOST LOCATIONS IN THE LINE OF FIRE AT SOME POINT.
SOME SEVERE THUNDERSTORMS CAN NOT BE RULED OUT ONCE AGAIN
TODAY...ALONG WITH ISOLATED FLASH FLOODING...WHERE STORMS CAN ALIGN
ALONG OUTFLOW BOUNDARIES PARALLEL TO THE STEERING FLOW. ANOTHER HOT
AND HUMID DAY LOOKS TO BE ON TAP...WITH A FEW SPOTS NEARING THE 100
DEGREE MARK IN HEAT INDICES.
STORMS WILL GRADUALLY WEAKEN INTO THE EVENING HOURS...ALTHOUGH SOME
NOCTURNAL ACTIVITY REMAINS AT LEAST SOMEWHAT OF A POSSIBILITY. LOWS
WILL BE MUGGY ONCE AGAIN AROUND THE 70 DEGREE MARK. SATURDAY WILL
FEATURE ANOTHER WARM AND HUMID DAY...ALONG WITH THE THREAT OF MORE
SCATTERED CONVECTION ACROSS THE AREA. THERE WILL BE LESS INSTABILITY
AVAILABLE AS MID-LEVEL WARMING TAKES PLACE FROM THE INFLUENCE OF THE
UPPER RIDGE. THIS WILL KEEP THE SEVERE AND FLASH FLOOD THREAT LOWER.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM EDT FRI AUG 22 2014
UPPER LEVEL RIDGING WILL REMAIN IN PLAY DURING THE DURATION OF THE
EXTENDED...WITH HEIGHTS EXPECTED TO BUILD AS THE HIGH SHIFTS NEWARD
ACROSS THE OHIO RIVER VALLEY. BUILDING HEIGHTS WILL THEN TRANSLATE
TO RISING TEMPERATURES. HOWEVER...MID AND UPPER LEVEL WINDS WILL
GENERALLY REMAIN OUT OF THE NORTH DURING THE FIRST FEW DAYS OF THE
EXTENDED. THIS...COUPLED WITH CLOUD COVER THAT WILL HAMPER MAXIMUM
SOLAR RADIATION...WILL KEEP HIGHS IN THE MID AND UPPER 80S THROUGH
TUESDAY. TEMPS MAY THEN COOL DOWN A COUPLE DEGREES AFTER TUESDAY AS
HIGH PRESSURE SITS OVERHEAD AND UPPER LEVEL HEIGHTS ASSOCIATED WITH
THE RIDGE BECOME MORE STATIC.
BASED ON THE LATEST FORECAST SOUNDINGS...WILL AGREE WITH PREVIOUS
FORECAST THAT EACH DAY SHOULD POSE A SHOWER/THUNDERSTORM THREAT
MAINLY IN THE AFTERNOON AND EVENING. GIVEN THE MID LEVEL DRYING FROM
MONDAY ON...WOULDN/T BE SURPRISED IF SOME OF THESE STORMS PRODUCE
SOME POTENTIAL HAIL. IN PROMISING NEWS...WITH THE RIDGING PATTERN IN
PLACE...WE WILL EXPERIENCE NO BOUNDARY FORCING UNTIL VERY LATE IN THE
FORECAST...SO THIS WILL HAMPER SOME OF THE BEST INSTABILITY AND
WIDESPREAD INITIATION. WINDS WILL BE LIGHT AT THE SURFACE...AND
REMAIN SO AS WE HEAD UP HIGHER INTO THE ATMOSPHERE. THAT BEING
SAID...AFTERNOON CAPE VALUES WILL BE ABOVE THE 2K J/KG RANGE THROUGH
MUCH OF THE EXTENDED...AND LAPSE RATES WILL RISE SLIGHTLY BY TUES/WED
TO 6 TO 6.5 C/KM...SO AFTERNOON HEATING AND INSTABILITY MAY BE ALL
THAT IS NECESSARY FOR SCATTERED CELL DEVELOPMENT EACH DAY. A BOUNDARY
WILL FINALLY PUSH INTO THE AREA BY THURS/FRI DAY 7/8 /PER THE LATEST
GFS MODEL RUN/. THIS WILL BRING A MORE WIDESPREAD CHANCE FOR RAIN AND
THUNDERSTORMS ACROSS THE AREA. HOWEVER...THERE IS QUITE A BIT OF
DISAGREEMENT IN THE EXTENDED MODELS THIS FAR OUT...SO DECIDED TO LEAN
ON THE ALLBLEND FOR POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 810 AM EDT FRI AUG 22 2014
PATCHY IFR OR WORSE FOG WILL LIFT AND DISSIPATE BY AROUND 13Z THIS
MORNING. CONVECTION WILL THREATEN ONCE AGAIN THIS AFTERNOON...WITH
LOCATIONS ALONG AND NORTHEAST OF A LINE FROM KIOB TO KJKL TO KI35
SEEING THE BETTER CHANCE OF MORE SUSTAINED CONVECTION. THE THREAT
WILL DIMINISH THIS EVENING...WITH FOG SETTING IN ONCE
AGAIN...PARTICULARLY AT ANY LOCATIONS THAT SEE HEAVIER RAINFALL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...JMW
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
325 AM EDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 159 AM EDT FRI AUG 22 2014
A COMPLEX OF THUNDERSTORMS IS CURRENTLY SLIDING SOUTHEAST ACROSS THE
SOUTHERN HALF OF OHIO. THIS COMPLEX IS WEAKENING AS EVIDENCED BY
THE WARMING CLOUD TOPS OVER THE PAST COUPLE OF HOURS. STILL...FEEL
THAT THIS WILL SKIRT THE NORTHEASTERN PORTION OF THE FORECAST AREA
WITH MEASURABLE RAINFALL IN THE 06 TO 10Z TIME RANGE...SO BEEFED UP
THE POPS TO ACCOUNT FOR THIS FEATURE. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 1031 PM EDT THU AUG 21 2014
A NEW FORECAST UPDATE WAS JUST SENT OUT ADDRESSING THE POSSIBILITY OF
THUNDERSTORMS MOVING FURTHER SOUTH INTO OUR FORECAST AREA LATER
TONIGHT THAN PREVIOUSLY THOUGHT. BASED ON CURRENT SATELLITE AND RADAR
IMAGERY...IT APPEARS THAT THE NORTHERN 2 OR 3 TIERS OF COUNTIES OF
OUR FORECAST AREA COULD EXPERIENCE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH A LARGE THUNDERSTORM COMPLEX THAT IS
CURRENTLY MOVING ACROSS PARTS OF CENTRAL INDIANA AND WEST CENTRAL
OHIO. THE SKY COVER...PRECIPITATION PROBABILITY...WEATHER TYPE...AND
PRECIPITATION AMOUNT FORECAST GRIDS WERE ALL UPDATED TO REFLECT
CURRENT TRENDS AND THE LATEST HRRR FORECAST DATA. THE HAZARDOUS
WEATHER OUTLOOK WAS ALSO UPDATED TO REFLECT THE NEW THUNDERSTORM
PROBABILITIES AND THE FURTHER SOUTHWARD MOVEMENT OF THE STORMS
THEMSELVES.
UPDATE ISSUED AT 758 PM EDT THU AUG 21 2014
SOME SIGNIFICANT UPDATES WERE MADE TO THE FORECAST GRIDS FOR THE REST
OF THE TONIGHT INTO EARLY TOMORROW MORNING. WILL BE ISSUING A NEW
ZONE FORECAST PRODUCT WITH THE PREFIRST PERIOD FROM DAY SHIFT
REMOVED. THE GRIDS AND THE TEXT FORECAST PRODUCT HAVE BOTH BEEN
UPDATED TO REFLECT THE FACT THAT ALL PRECIPITATION HAS NOW MOVED OUT
OF EASTERN KENTUCKY. THE LATEST NAM12 AND HRRR MODELS BOTH ARE
KEEPING PRECIPITATION OUT OF THE AREA UNTIL 8 OR 9Z TONIGHT. BASED ON
THIS...AND THE LATEST RADAR IMAGERY...WHICH HAS A LARGE THUNDERSTORM
COMPLEX MOVING ACROSS NORTHERN INDIANA...IT APPEARS THAT THE MODEL
DATA IS ON TRACK AND THAT THE STORMS CURRENTLY MOVING ACROSS INDIANA
WILL STAY MOSTLY NORTH OF THE AREA AS THEY MOVE ACROSS SOUTHERN OHIO
LATE TONIGHT AND EARLY TOMORROW. WE MAY SEE A FEW SHOWERS AND STORMS
FIRE UP ALONG THUNDERSTORM OUTFLOWS IN OUR NORTHERNMOST COUNTIES
ALONG AND NORTH OF I-64 AROUND 8Z TONIGHT. THE SKY COVER GRIDS AND
FORECAST WERE ALSO UPDATED TO REFLECT CURRENT TRENDS OF PARTLY TO
MOSTLY CLOUDY SKIES ACROSS THE FORECAST AREA. CONSIDERING THE AMOUNT
OF RAIN EASTERN KENTUCKY HAS RECEIVED THE PAST SEVERAL DAYS...AND
WITH CLOUDS BREAKING UP A BIT TONIGHT...WE SHOULD STILL SEE AREAS OF
FOG IN OUR VALLEYS. LOCATIONS THAT RECEIVED RAINFALL
TODAY...INCLUDING RIDGETOP LOCATIONS SUCH AS THE JACKSON WEATHER
OFFICE...COULD ALSO SEE SOME MVFR FOG OVERNIGHT. THE HAZARDOUS
WEATHER OUTLOOK WILL ALSO BE UPDATED SHORTLY TO REFLECT THE LACK OF
THUNDER THROUGH DAWN TOMORROW. A NEW SET OF ZONES WILL ALSO BE ISSUED
SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 355 PM EDT THU AUG 21 2014
19Z SFC ANALYSIS SHOWS A SEASONALLY STRONG AREA OF LOW PRESSURE OVER
THE HIGH PLAINS WITH HIGH PRESSURE OVER THE DEEP SOUTH. THIS NEARBY
HIGH IS NOT ENOUGH TO PREVENT THE LATEST INCARNATION OF MCS ACTIVITY
FROM DIVING THROUGH EASTERN KENTUCKY. THIS IS TAKING ADVANTAGE OF
HIGH INSTABILITY THROUGHOUT THE AREA GIVEN TEMPERATURES IN THE UPPER
80S AND DEWPOINTS IN THE LOWER 70S. IN ADDITION TO THE SEVERE
THUNDERSTORM THREAT...HIGH PWS...LOW FFG...AND A POTENTIAL FOR
TRAINING WILL KEEP FLASH FLOODING A CONCERN THROUGH THE EVENING.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST WITH A LARGE AREA OF RIDGING STRETCHING FROM THE
LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY. AS IT DOES SO...A
DEEP LOW TO THE NORTHEAST WILL SEND PACKETS OF ENERGY THROUGH THE
OHIO VALLEY AND INTO THE CENTRAL APPALACHIANS IN FAIRLY FAST
NORTHWEST FLOW. THIS WILL PLACE AT LEAST NORTHEAST PARTS OF THE JKL
CWA IN THE STORM TRACK AND AS PRIME REAL ESTATE FOR MCS ACTIVITY.
GIVEN THE MODEL AGREEMENT HAVE FAVORED A BLEND WITH EXTRA EMPHASIS ON
THE HRRR AND NAM12 FOR THE FIRST 12 TO 24 HOURS.
SENSIBLE WEATHER WILL FEATURE ON GOING THUNDERSTORM ACTIVITY
DIMINISHING INTO THE EVENING...BUT PROGRESSING SOUTH WITH THE FAVORED
INSTABILITY. LATER TONIGHT...PARTLY CLOUDS SKIES AND THE MOISTURE
FROM THE RAIN OF THIS AFTERNOON AND EVENING WILL LIKELY LEAD TO
AREAS OF FOG...LOCALLY DENSE. INDICATIONS ARE THAT THE NEXT ROUND OF
STORMS STAY TO THE NORTHEAST OF THE CWA TONIGHT. AFTER THE FOG BURNS
OFF ON FRIDAY MORNING THE INSTABILITY WILL BUILD AGAIN WITH ANOTHER
VERY HUMID AND WARM DAY. THIS WILL BE A SIMILAR SETUP FOR SEVERE AND
EXCESSIVE RAIN POTENTIAL...MAINLY IN THE NORTHEAST BASED ON THE
EXPECTATION OF EARLY STORMS TRACKING JUST OUTSIDE OF THE CWA AND
DEVELOPMENT ON THEIR SOUTHWEST FLANKS. LIKEWISE...PATCHY FOG WILL BE
AN ISSUE FOR THE AREA LATER FRIDAY NIGHT GIVEN A SIMILAR SETUP...
BUT STILL DEPENDENT ON THE RAINS EARLY IN THE DAY AND EVENING.
USED THE CONSSHORT AS A STARTING POINT FOR THE T...TD...AND WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND FRIDAY NIGHT.
AS FOR POPS...ENDED UP HIGHER THAN GUIDANCE...EXCEPT FOR THE MET
NORTH OF JKL ON FRIDAY NIGHT...THROUGH SATURDAY MORNING OWING TO THE
TENDENCY FOR STORMS TO EXPAND SOUTHWEST OF THEIR DEPICTIONS IN THE
MODELS.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 324 AM EDT FRI AUG 22 2014
UPPER LEVEL RIDGING WILL REMAIN IN PLAY DURING THE DURATION OF THE
EXTENDED...WITH HEIGHTS EXPECTED TO BUILD AS THE HIGH SHIFTS NEWARD
ACROSS THE OHIO RIVER VALLEY. BUILDING HEIGHTS WILL THEN TRANSLATE
TO RISING TEMPERATURES. HOWEVER...MID AND UPPER LEVEL WINDS WILL
GENERALLY REMAIN OUT OF THE NORTH DURING THE FIRST FEW DAYS OF THE
EXTENDED. THIS...COUPLED WITH CLOUD COVER THAT WILL HAMPER MAXIMUM
SOLAR RADIATION...WILL KEEP HIGHS IN THE MID AND UPPER 80S THROUGH
TUESDAY. TEMPS MAY THEN COOL DOWN A COUPLE DEGREES AFTER TUESDAY AS
HIGH PRESSURE SITS OVERHEAD AND UPPER LEVEL HEIGHTS ASSOCIATED WITH
THE RIDGE BECOME MORE STATIC.
BASED ON THE LATEST FORECAST SOUNDINGS...WILL AGREE WITH PREVIOUS
FORECAST THAT EACH DAY SHOULD POSE A SHOWER/THUNDERSTORM THREAT
MAINLY IN THE AFTERNOON AND EVENING. AND GIVEN THE MID LEVEL DRYING
FROM MONDAY ON...WOULDN/T BE SURPRISED IF SOME OF THESE STORMS
PRODUCE SOME POTENTIAL HAIL. IN PROMISING NEWS...GIVEN THE RIDGING
PATTERN IN PLACE...WE WILL EXPERIENCE NO BOUNDARY FORCING UNTIL VERY
LATE IN THE FORECAST...SO THIS WILL HAMPER SOME OF THE BEST
INSTABILITY AND WIDESPREAD INITIATION. WINDS WILL BE LIGHT AT THE
SURFACE...AND REMAIN SO AS WE HEAD UP HIGHER INTO THE ATMOSPHERE.
THAT BEING SAID...AFTERNOON CAPE VALUES WILL BE ABOVE THE 2K J/KG
RANGE THROUGH MUCH OF THE EXTENDED...AND LAPSE RATES WILL RISE
SLIGHTLY BY TUES/WED TO 6 TO 6.5 C/KM...SO AFTERNOON HEATING AND
INSTABILITY MAY BE ALL THAT IS NECESSARY FOR SCATTERED CELL
DEVELOPMENT EACH DAY. A BOUNDARY WILL FINALLY PUSH INTO THE AREA BY
THURS/FRI DAY 7/8 /PER THE LATEST GFS MODEL RUN/. THIS WILL BRING A
MORE WIDESPREAD CHANCE FOR RAIN AND THUNDERSTORMS ACROSS THE AREA.
HOWEVER...THERE IS QUITE A BIT OF DISAGREEMENT IN THE EXTENDED
MODELS THIS FAR OUT...SO DECIDED TO LEAN ON THE ALLBLEND FOR POPS AT
THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 159 AM EDT FRI AUG 22 2014
A COMPLEX OF THUNDERSTORMS WILL WEAKEN AS IT SKIRTS BY ACROSS
NORTHEASTERN KENTUCKY BETWEEN 06 AND 10Z. THIS WILL LIKELY AFFECT A
LINE FROM KSYM TO KSJS BETWEEN 07 AND 09Z. MVFR VISIBILITIES ALONG
WITH SOME GUSTY NORTHWESTERLY WINDS UP TO AROUND 20 KTS WILL
ACCOMPANY THE LEADING EDGE OF THE SHOWERS AND STORMS. EXPECT MVFR OR
WORSE FOG WILL SET IN ACROSS THE REST OF THE AREA THROUGH DAWN...WITH
IFR OR WORSE FOG RESTRICTED TO THE DEEPER VALLEYS...PARTICULARLY
THOSE THAT SAW RECENT HEAVY RAINFALL. ONCE THE FOG BURNS OFF THROUGH
AROUND 13Z...A RENEWED THREAT OF CONVECTION WILL RETURN...MAINLY
DURING THE AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
159 AM EDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 159 AM EDT FRI AUG 22 2014
A COMPLEX OF THUNDERSTORMS IS CURRENTLY SLIDING SOUTHEAST ACROSS THE
SOUTHERN HALF OF OHIO. THIS COMPLEX IS WEAKENING AS EVIDENCED BY
THE WARMING CLOUD TOPS OVER THE PAST COUPLE OF HOURS. STILL...FEEL
THAT THIS WILL SKIRT THE NORTHEASTERN PORTION OF THE FORECAST AREA
WITH MEASURABLE RAINFALL IN THE 06 TO 10Z TIME RANGE...SO BEEFED UP
THE POPS TO ACCOUNT FOR THIS FEATURE. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 1031 PM EDT THU AUG 21 2014
A NEW FORECAST UPDATE WAS JUST SENT OUT ADDRESSING THE POSSIBILITY OF
THUNDERSTORMS MOVING FURTHER SOUTH INTO OUR FORECAST AREA LATER
TONIGHT THAN PREVIOUSLY THOUGHT. BASED ON CURRENT SATELLITE AND RADAR
IMAGERY...IT APPEARS THAT THE NORTHERN 2 OR 3 TIERS OF COUNTIES OF
OUR FORECAST AREA COULD EXPERIENCE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH A LARGE THUNDERSTORM COMPLEX THAT IS
CURRENTLY MOVING ACROSS PARTS OF CENTRAL INDIANA AND WEST CENTRAL
OHIO. THE SKY COVER...PRECIPITATION PROBABILITY...WEATHER TYPE...AND
PRECIPITATION AMOUNT FORECAST GRIDS WERE ALL UPDATED TO REFLECT
CURRENT TRENDS AND THE LATEST HRRR FORECAST DATA. THE HAZARDOUS
WEATHER OUTLOOK WAS ALSO UPDATED TO REFLECT THE NEW THUNDERSTORM
PROBABILITIES AND THE FURTHER SOUTHWARD MOVEMENT OF THE STORMS
THEMSELVES.
UPDATE ISSUED AT 758 PM EDT THU AUG 21 2014
SOME SIGNIFICANT UPDATES WERE MADE TO THE FORECAST GRIDS FOR THE REST
OF THE TONIGHT INTO EARLY TOMORROW MORNING. WILL BE ISSUING A NEW
ZONE FORECAST PRODUCT WITH THE PREFIRST PERIOD FROM DAY SHIFT
REMOVED. THE GRIDS AND THE TEXT FORECAST PRODUCT HAVE BOTH BEEN
UPDATED TO REFLECT THE FACT THAT ALL PRECIPITATION HAS NOW MOVED OUT
OF EASTERN KENTUCKY. THE LATEST NAM12 AND HRRR MODELS BOTH ARE
KEEPING PRECIPITATION OUT OF THE AREA UNTIL 8 OR 9Z TONIGHT. BASED ON
THIS...AND THE LATEST RADAR IMAGERY...WHICH HAS A LARGE THUNDERSTORM
COMPLEX MOVING ACROSS NORTHERN INDIANA...IT APPEARS THAT THE MODEL
DATA IS ON TRACK AND THAT THE STORMS CURRENTLY MOVING ACROSS INDIANA
WILL STAY MOSTLY NORTH OF THE AREA AS THEY MOVE ACROSS SOUTHERN OHIO
LATE TONIGHT AND EARLY TOMORROW. WE MAY SEE A FEW SHOWERS AND STORMS
FIRE UP ALONG THUNDERSTORM OUTFLOWS IN OUR NORTHERNMOST COUNTIES
ALONG AND NORTH OF I-64 AROUND 8Z TONIGHT. THE SKY COVER GRIDS AND
FORECAST WERE ALSO UPDATED TO REFLECT CURRENT TRENDS OF PARTLY TO
MOSTLY CLOUDY SKIES ACROSS THE FORECAST AREA. CONSIDERING THE AMOUNT
OF RAIN EASTERN KENTUCKY HAS RECEIVED THE PAST SEVERAL DAYS...AND
WITH CLOUDS BREAKING UP A BIT TONIGHT...WE SHOULD STILL SEE AREAS OF
FOG IN OUR VALLEYS. LOCATIONS THAT RECEIVED RAINFALL
TODAY...INCLUDING RIDGETOP LOCATIONS SUCH AS THE JACKSON WEATHER
OFFICE...COULD ALSO SEE SOME MVFR FOG OVERNIGHT. THE HAZARDOUS
WEATHER OUTLOOK WILL ALSO BE UPDATED SHORTLY TO REFLECT THE LACK OF
THUNDER THROUGH DAWN TOMORROW. A NEW SET OF ZONES WILL ALSO BE ISSUED
SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 355 PM EDT THU AUG 21 2014
19Z SFC ANALYSIS SHOWS A SEASONALLY STRONG AREA OF LOW PRESSURE OVER
THE HIGH PLAINS WITH HIGH PRESSURE OVER THE DEEP SOUTH. THIS NEARBY
HIGH IS NOT ENOUGH TO PREVENT THE LATEST INCARNATION OF MCS ACTIVITY
FROM DIVING THROUGH EASTERN KENTUCKY. THIS IS TAKING ADVANTAGE OF
HIGH INSTABILITY THROUGHOUT THE AREA GIVEN TEMPERATURES IN THE UPPER
80S AND DEWPOINTS IN THE LOWER 70S. IN ADDITION TO THE SEVERE
THUNDERSTORM THREAT...HIGH PWS...LOW FFG...AND A POTENTIAL FOR
TRAINING WILL KEEP FLASH FLOODING A CONCERN THROUGH THE EVENING.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST WITH A LARGE AREA OF RIDGING STRETCHING FROM THE
LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY. AS IT DOES SO...A
DEEP LOW TO THE NORTHEAST WILL SEND PACKETS OF ENERGY THROUGH THE
OHIO VALLEY AND INTO THE CENTRAL APPALACHIANS IN FAIRLY FAST
NORTHWEST FLOW. THIS WILL PLACE AT LEAST NORTHEAST PARTS OF THE JKL
CWA IN THE STORM TRACK AND AS PRIME REAL ESTATE FOR MCS ACTIVITY.
GIVEN THE MODEL AGREEMENT HAVE FAVORED A BLEND WITH EXTRA EMPHASIS ON
THE HRRR AND NAM12 FOR THE FIRST 12 TO 24 HOURS.
SENSIBLE WEATHER WILL FEATURE ON GOING THUNDERSTORM ACTIVITY
DIMINISHING INTO THE EVENING...BUT PROGRESSING SOUTH WITH THE FAVORED
INSTABILITY. LATER TONIGHT...PARTLY CLOUDS SKIES AND THE MOISTURE
FROM THE RAIN OF THIS AFTERNOON AND EVENING WILL LIKELY LEAD TO
AREAS OF FOG...LOCALLY DENSE. INDICATIONS ARE THAT THE NEXT ROUND OF
STORMS STAY TO THE NORTHEAST OF THE CWA TONIGHT. AFTER THE FOG BURNS
OFF ON FRIDAY MORNING THE INSTABILITY WILL BUILD AGAIN WITH ANOTHER
VERY HUMID AND WARM DAY. THIS WILL BE A SIMILAR SETUP FOR SEVERE AND
EXCESSIVE RAIN POTENTIAL...MAINLY IN THE NORTHEAST BASED ON THE
EXPECTATION OF EARLY STORMS TRACKING JUST OUTSIDE OF THE CWA AND
DEVELOPMENT ON THEIR SOUTHWEST FLANKS. LIKEWISE...PATCHY FOG WILL BE
AN ISSUE FOR THE AREA LATER FRIDAY NIGHT GIVEN A SIMILAR SETUP...
BUT STILL DEPENDENT ON THE RAINS EARLY IN THE DAY AND EVENING.
USED THE CONSSHORT AS A STARTING POINT FOR THE T...TD...AND WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND FRIDAY NIGHT.
AS FOR POPS...ENDED UP HIGHER THAN GUIDANCE...EXCEPT FOR THE MET
NORTH OF JKL ON FRIDAY NIGHT...THROUGH SATURDAY MORNING OWING TO THE
TENDENCY FOR STORMS TO EXPAND SOUTHWEST OF THEIR DEPICTIONS IN THE
MODELS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 315 PM EDT THU AUG 21 2014
STRONG RIDGING WILL LIKELY HOLD OVER THE AREA FOR THE BALANCE OF THE
EXTENDED PART OF THE FORECAST. SHOWER AND THUNDERSTORM CHANCES WILL
CONTINUE EACH DAY THROUGH THE MIDDLE OF NEXT WEEK. IN
ADDITION...WARM AND MUGGY CONDITIONS WILL REMAIN ANCHORED BENEATH
THE RIDGE. BEST TIME FOR SHOWERS AND STORMS WILL CONTINUE TO BE EACH
AFTERNOON/EVENING...BUT CANNOT RULE OUT AN ISOLATED SHOWER OR STORM
AT ANY TIME INTO NEXT WEEK. GFS MOS IS LIKELY A BIT TOO HIGH AND
WILL CONTINUE TO GO BETWEEN GFS AND MET MOS THROUGH SATURDAY. ECMWF
SEEMS TO BE A GOOD COMPROMISE WITH REGARDS TO TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 159 AM EDT FRI AUG 22 2014
A COMPLEX OF THUNDERSTORMS WILL WEAKEN AS IT SKIRTS BY ACROSS
NORTHEASTERN KENTUCKY BETWEEN 06 AND 10Z. THIS WILL LIKELY AFFECT A
LINE FROM KSYM TO KSJS BETWEEN 07 AND 09Z. MVFR VISIBILITIES ALONG
WITH SOME GUSTY NORTHWESTERLY WINDS UP TO AROUND 20 KTS WILL
ACCOMPANY THE LEADING EDGE OF THE SHOWERS AND STORMS. EXPECT MVFR OR
WORSE FOG WILL SET IN ACROSS THE REST OF THE AREA THROUGH DAWN...WITH
IFR OR WORSE FOG RESTRICTED TO THE DEEPER VALLEYS...PARTICULARLY
THOSE THAT SAW RECENT HEAVY RAINFALL. ONCE THE FOG BURNS OFF THROUGH
AROUND 13Z...A RENEWED THREAT OF CONVECTION WILL RETURN...MAINLY
DURING THE AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
402 AM EDT FRI AUG 22 2014
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE ALONG A STALLED FRONTAL BOUNDARY
ACROSS THE MID ATLANTIC STATES LATE TODAY AND TONIGHT. THE FRONT
WILL PUSH SOUTHWEST AS A COLD FRONT SATURDAY. HIGH PRESSURE WILL
BUILD SOUTH FROM NEW ENGLAND INTO THE MID ATLANTIC THIS WEEKEND
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
THIS WEEK HAS BEEN FAIRLY CUT/PASTE EACH DAY W/ THE CONDITIONS OF
TEMPS...HUMIDITY...SKY CONDITIONS AND POPS. THIS MOIST AIRMASS WILL
FINALLY UNDERGO A TRANSITION AND BEGIN TO EXIT THE REGION...BUT NOT
UNTIL SAT EVE. TILL THEN...ANOTHER SIMILAR DAY TO AT LEAST THE LAST
TWO IS EXPECTED FOR THE AREA. DEWPOINTS CONTINUE TO HOVER WITHIN THE
65-70F RANGE WHICH IS PLENTY HUMID AND PREVENTING OUR TEMPS FROM
DROPPING BELOW THE 70F MARK FOR MANY AREAS.
GROUND FOG/LOW STRATUS NOT AS DENSE OR PREVALENT AT THIS TIME
COMPARED TO LAST NIGHT...EVEN W/ CALM WINDS AND ANOTHER DAY OF RAIN
ACCUMULATION STRANDS ACROSS THE REGION. UPPER DEBRIS CARRIED OUT
AHEAD OF DISSIPATED CONVECTION FROM THE NW HAS OVERCOME MUCH OF THE
AREA AND LIKELY LIMITING FOG FORMATION. STILL EXPECTING A BRIEF FEW
HRS OF LOW STRATUS JUST W/IN THE BOUNDARY LAYER TOWARD DAWN WHEN THE
TEMPS ARE AT THEIR MIN AND RADIATIONAL EFFECTS FROM THE RISING SUN
BEGIN TO TRANSITION THE NEAR SFC LAYER - BUT ONLY PATCHY DENSE VLY
FOG OR STRAITED BANDS OF LOW STRATUS FOR LOCALIZED AREAS.
OUR AREA IS SURROUNDED TO THE EAST AND WEST BY CONTINUED SHOWER AND
TSTM ACTIVITY OVERNIGHT...W/ THE ERN STORMS HEADING OFF THE COAST
AND ANOTHER BATCH APPROACHING THE CNTRL APLCNS. A LOCAL UPPER
IMPULSE LIKELY KICKING-OFF ANOTHER ROUND OF CELLS IN A LINEAR
FASHION FROM ERN OH DOWN INTO NRN WV. HRRR AND MOST OTHER LOCAL WRF
MEMBERS CARRYING THIS ACTIVITY OVER THE MTNS BUT THEN QUICKLY
DISSIPATE IT TO AN INNOCUOUS BATCH OF LIGHT STRATIFORM SHOWERS. LIKE
THE PREV FEW DAYS...TODAY WILL BE MOSTLY DRY - THOUGH HUMID - AND
DODGING SCT SHOWERS/ISLD TSTMS LATER THIS AFTN/EVE. THE EARLIEST
ACTIVITY WILL DICTATE THE LATER ACTIVITY...W/ LOCALLY HEAVY
DOWNPOURS EXPECTED AND GUSTY WINDS W/ THE STRONGER CELLS. THE 00Z
4/22 KIAD SOUNDING SHOWS GOOD LAPSE RATES IN THE LOW LEVELS AND
MOIST ADIABATIC HEADING UP THRU THE REST OF THE COLUMN...MUCH MORE
MOIST THAN 24HRS PRIOR. THIS PROFILE IS EXPECTED TO CARRY OVER FOR
TODAY`S ACTIVITY BUT END UP MORE STABLE THAN THU`S...AND A LESS
FAVORABLE WIND PROFILE.
WINDS BELOW 10KFT MAY HAVE A BULK AND MEAN SHEAR OF ONLY AROUND 5KT
W/ A MUCH STRONGER UPPER FLOW. A POTENT UPPER JET OF 80-100KT WON`T
HELP LOW-TOP CONVECTION MUCH AND MAY IN-FACT SHEAR OFF TALLER CELLS.
THE LACK OF GOOD MID/LOW LEVEL STEERING FLOW INCREASES THE POTENTIAL
FOR FLOODING AND FLASH FLOODING IN LOCALIZED AREAS...W/ A REGIME
THAT MAY ALLOW FOR TRAINING CELLS UNDER THE RIGHT CONDITIONS OR
ALONG A PRE-EXISTING BOUNDARY. WILL KEEP THIS THE HIGHLIGHT IN THE
HWO...WHICH WILL BE THE BIGGEST THREAT OUTSIDE OF A FEW
STRONG/MARGINALLY SVR TSTMS.
SUNSET WILL AGAIN BE THE START OF TSTM DISSIPATION W/ ONLY A HANDFUL
OF SHOWERS CONTINUING TO SLIDE ACROSS THE AREA INTO THE LATE NIGHT
HRS. DEWPOINTS WILL CONTINUE TO HOVER NEAR 70F FOR ANOTHER HUMID
OVERNIGHT. BATCHES OF MID CLOUD DECKS WILL ALSO HELP SHELTER THE
AREA AND KEEP OVERNIGHT LOWS MODERATED NEAR THE 70F MARK.
TOWARD SUNRISE SAT...THE DYNAMIC TRANSITION WILL BEGIN TO TAKE PLACE
OFF TO OUR NORTH AND EAST. THE UPPER LOW SITTING OVER THE GREAT
LAKES FOR THE PAST COUPLE OF DAYS WILL BE ABSORBED INTO THE UPPER
FLOW AND HELP DIG THE RETROGRADED PORTION OF AN UPPER TROUGH BACK
OVER THE AREA ON SAT. THE LAST ARM OF THIS FEATURE WILL DRIFT ACROSS
THE REGION DURING THE DAYTIME HRS AND BRING MORE SCATTERED SHOWERS
AND TSTMS. HIGH TEMPS WILL BE THEIR COOLEST IN DAYS BUT STILL
REACHING THE L80S BY MID AFTN. HOWEVER...THE INSTABILITY PROFILE
WILL LOOK MORE LIKE THU`S...W/ SFC-BASED CAPES POTENTIALLY IN THE
1-1.5K RANGE W/ A COOLER UPPER LEVEL TEMP PROFILE FROM THE UPPER
TROUGH PASSAGE. STABILITY MAY COME HOWEVER IN THE FORM OF AN ELY LOW
LEVEL WIND...WHICH COULD LIMIT THE CONVECTIVE INITIATION POTENTIAL
IF THE CAP IS TOO STRONG AND SFC TEMPS DON`T REACH THE APPROPRIATE
LEVELS - ESPEC CLOSER TO THE BAY AND NEAR THE MASON-DIXON LINE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
SFC HIPRES WL BE BLDG DOWN THE COAST SAT NGT-SUN. AS H5 RDG AXIS
CONTS TO SHARPEN...DRIER AIR WL BE ENTRAINED...AND GRDLY ERODE THE
LLVL MARITIME SATURATION. THAT WL HPPN FIRST ALONG I-95 SAT EVNG.
THINK WE/LL NEED TO HOLD ONTO POPS FOR THE MTNS ALL NGT SAT. FIRST
CLRG WL COME TO METRO BALT ELY SUN...AND WL SPREAD THAT TO THE SW
ACRS THE REMAINDER OF THE CWFA THRUT THE DAY. SUNDAY WL BE A NICER
DAY THAN SAT...EVEN FOR THE MTNS WHICH MAY AVG OUT AS PTSUN VS MOSUN
/OR EVEN SUNNY/.
SINCE ITLL BE CLDY...AND DEWPTS WL BE DROPPING THRU THE 60S...DIDNT
LWR MIN-T AS MUCH AS I CUD HV. AM TAKING A RESERVED APPROACH...W/
MIN-T IN THE 60S AS WELL. DID GO ON THE COOLER EDGE OF MAXT GDNC FOR
SUN...BUT BELIEVE PROLONGED ELY FETCH WL KEEP TEMPS FAIRLY CLOSE TO
WATER TEMPS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
SFC HIPRES AND H5 RDG AXIS CONT TO BUILD OVER THE MID ATLC THRU THE
XTNDD PD. FLOW WL BE LGT...BUT TEMPS WL GRDLY BE MODERATING BY
MIDWEEK.
A CDFNT DROPPING TWD THE AREA LT WK WL PROVIDE THE ONLY PCPN RISK
DURING THE WORK WEEK.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
SOME AREAS OF GROUND/VLY FOG IN TYPICAL PIEDMONT AND COASTAL AREAS
BUT NOT SEEING A DEVELOPING DENSE LOW CLOUD BANK EITHER ATTM. THE
NEXT FEW HRS MAY SEE BATCHES OF LOW-END MVFR CIGS/VSBYS DEVELOP BUT
LIKELY NOT IFR OR LOWER...OUTSIDE OF A BRIEF PERIOD. SKIES AFTER
SUNRISE WILL AGAIN WAVER IN/OUT OF PARTLY SUNNY/MOSTLY CLOUDY SINCE
WE STILL HAVE A MOIST ATMOS. SCATTERED SHOWERS AND LATE-DAY TSTMS
POSSIBLE AGAIN ACROSS THE REGION. CONDS WILL IMPROVE AGAIN
OVERNIGHT...THOUGH A FEW ISOLATED SHOWERS AND MORE DENSE CLOUD COVER
IS EXPECTED INTO EARLY SAT W/ MORE SHOWER/TSTMS EXPECTED ON SAT.
MAY HV SOME LOW CLDS OR PATCHY FOG TO START THE DAY SUN...OTRW VFR
WL PREVAIL THRU TUE.
&&
.MARINE...
SCA CONDITIONS NOT ANTICIPATED TODAY OR TONIGHT. A FEW TSTMS
POSSIBLE THIS AFTN/EVE OVER THE WATERS. ELY ONSHORE FLOW WILL
STRENGTHEN INTO EARLY SAT...W/ SOME POSSIBLY MARGINAL SCA CONDITIONS
ALONG THE WRN SHORES AND MAIN STEM OF THE MD BAY.
ELY/NELY FLOW WL PREVAIL SAT NGT INTO SUN AS HIPRES DRAINS
COOLER/DRIER AIR ACRS WATERS. GDNC SUGGESTS WNDS WL REMAIN AOB 15 KT
DURING THIS TIME. WL GO THAT ROUTE IN THE FCST ATTM...BUT WUDNT BE
SHOCKED IF A FEW HIER GUSTS APPROACHED SCA CRIT IN THE MAIN CHANNEL
OF THE MID BAY. BYD THAT...WNDS WL LESSEN AS HIPRES BLDS.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS ONLY INCHES HIGHER THAN ASTRO NORMALS. SHOULD BE
PROBLEM FREE FOR THE NEXT COUPLE OF DAYS. FLOW TURNS ONSHORE AGAIN
THIS WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HTS
NEAR TERM...GMS
SHORT TERM...HTS
LONG TERM...HTS
AVIATION...GMS/HTS
MARINE...GMS/HTS
TIDES/COASTAL FLOODING...HTS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
307 AM EDT FRI AUG 22 2014
.SYNOPSIS...
A FRONTAL BOUNDARY REMAINS NEARLY STATIONARY ACROSS THE AREA INTO
THE UPCOMING WEEKEND. HIGH PRESSURE FROM NEW ENGLAND IS SLOW TO
BUILD OVER THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATE THIS EVENING TO MAKE MINOR TWEAK TO TIMING AND LONATION
OVERNIGHT POPS. MORE WIDESPREAD SHOWERS BREAKING OUT ACROSS
CENTRAL VA ARE IN RESPONSE TO THE SHORTWAVE JUST MOVING INTO THE
REGION FROM THE NW. THE RAP IS HANDLING THIS FEATURE AND FORCING
VERY WELL. EXPECT THE PRECIP TO CONTINUE TO EXPAND SOMEWHAT IN
COVERAGE AND SPREAD EAST ACROSS CENTRAL VA AND THEN THE COAST
INCLUDING MD...EASTERN SHORE AND SOUTHEAST VA. THUNDER ACTIVITY
WITH THIS SHOULD BE LIMITED THOUGH CANNOT RULE OUT A FEW RUMBLES
ESPECIALLY ACROSS NORTH CENTRAL VA...MD AND THE EASTERN SHORE.
OVERALL TEMP FORECASTS REMAIN ON TRACK.
PREVIOUS DISCUSSION...
THE CURRENT SURFACE ANALYSIS INDICATES WEAK BROAD LOW PRESSURE IN
VICINITY OF THE GREAT LAKES WITH A BOUNDARY EXTENDING SOUTHWARD FROM
E-CENTRAL PA THROUGH THE WESTERN SHORE OF THE CHESAPEAKE BAY.
THUNDERSTORMS HAVE DEVELOPED ALONG THE BOUNDARY OVER PA AHEAD OF A
~100KT UPPER JET DIVING ACROSS THE ERN GREAT LAKES. SPC MESOANALYSIS
INDICATES 35-40KT OF EFFECTIVE SHEAR FROM SE PA THROUGH THE LOWER MD
ERN SHORE ALONG WITH AN AXIS OF 1500J/KG OF MLCAPE. THUNDERSTORM
COVERAGE IS EXPECTED TO INCREASE OVER THE ERN SHORE LATER THIS
AFTERNOON INTO THE EVENING HOURS AS THE JET DIVES SE. A FEW STRONGER
STORMS ARE POSSIBLE BASED ON FAVORABLE DYNAMIC AND THERMODYNAMIC
PARAMETERS...WITH THE PRIMARY THREAT BEING STRONG WIND GUSTS. THE
MAIN LIMITING FACTOR WILL BE RATHER WEAK LAPSE RATES. OTHERWISE...A
CHC (30-40%) OF GENERAL THUNDER IS EXPECTED OVERNIGHT AS THE UPPER
JET ENERGY PASSES OVER THE AREA AND THE SURFACE BOUNDARY REMAINS IN
PLACE. LESS FOG IS EXPECTED DUE TO THE PRESENCE OF MID/UPPER LEVEL
CLOUD COVER. OVERNIGHT LOWS SHOULD RANGE FROM THE UPPER 60S TO LOW
70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
MID/UPPER NW FLOW REMAINS OVER THE REGION FRIDAY INTO THE WEEKEND. A
MORE VIGOROUS WAVE DROPS THROUGH THE FLOW ACROSS THE AREA FRIDAY
NIGHT. THIS WILL PROVIDE BEST CHC OF AND GREATEST AREAL COVERAGE OF
SHOWERS/TSTMS ACROSS THE LOCAL AREA DURING THE SHORT-TERM PERIOD DUE
TO MORE FAVORABLE/STRONGER UPPER JET SUPPORT. POCKETS OF MODERATE TO
HEAVY RAIN ARE POSSIBLE GIVEN MODEST MOISTURE AND FAVORABLE UPPER
SUPPORT. HIGH PRESSURE BUILDS OVER NEW ENGLAND SATURDAY AND SLOWLY
PUSHES INTO THE REGION BY SUNDAY. THIS WILL PUSH THE REMNANT FRONT S
OF THE AREA. CHC POPS WILL CONTINUE EARLY SATURDAY...WITH A STEADY
DRYING TREND COMMENCING SATURDAY AFTERNOON FROM NNE-SSW AS THE HIGH
BUILDS INTO THE REGION.
HIGHS FRIDAY SHOULD BE MAINLY 85-90...AND THEN FROM THE LOW TO MID
80S SATURDAY (UPPER 70S ALONG THE ATLANTIC BEACHES)...WITH UPPER 70S
TO LOW 80S SUNDAY. LOWS SHOULD BE IN THE UPPER 60S TO LOW 70S
SATURDAY...AND IN THE 60S SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED FORECAST PERIOD WILL CONSIST OF MAINLY NE FLOW AS HIGH
PRESSURE TO THE NORTH RIDGES SOUTH WHILE AN AREA OF LOW PRESSURE
EMERGES FROM THE BAHAMAS. THIS PATTERN WILL MAINTAIN A COOLER
MARITIME AIRMASS IN PLACE OVER THE AREA THROUGH WED BEFORE HIGH
PRESSURE AT THE SURFACE AND ALOFT BEGIN TO CENTER THEMSELVES OVER
THE FA. AT THIS POINT SUBSIDENCE WILL PREVAIL AND WILL HELP TO DRY
THE ATMOSPHERE. PRECIP ALONG THE VA/NC COAST CAN NOT BE COMPLETELY
RULED OUT DUE TO THE INFLUX OF MOISTURE NORTH AS THE SURFACE LOW
FORMS TO THE SOUTH. THERE IS SOME MODEL DISCREPANCY IN REGARDS TO
THE POSITION AND STRENGTH OF THE LOW OVER THE TROPICAL ATLANTIC. AND
DUE TO THE LARGE DEGREE OF CHANGE IN MODEL RUNS...AT THIS POINT...
WILL NOT MODIFY THE PREVIOUS FORECAST TOO MUCH.
TEMPS WILL REMAIN BELOW AVERAGE FOR MUCH OF THE EXTENDED PERIOD
WITH HIGHS AROUND 80 MON AND TUES...WARMING SLIGHTLY INTO THE MID 80S
WED AND THUR. SEASONAL LOW TEMPS IN THE LOW TO MID 60S ARE LIKELY
AS THE MARITIME AIRMASS WILL LIMIT SIGNIFICANT OVERNIGHT COOLING.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A WARM FRONT EXTENDED FROM NEAR WASHINGTON DC THROUGH
EASTERN VIRGINIA (BETWEEN RICHMOND AND HAMPTON ROADS) AND INTO
EASTERN NORTH CAROLINA. WINDS WERE MAINLY FROM THE W/SW WEST OF
THE BOUNDARY AND FROM THE E/SE TO THE EAST OF IT. THIS FRONT WILL
MOVE TOWARD THE COAST OVERNIGHT. LOW PRESSURE MAY DEVELOP JUST OFF
THE COAST TODAY WHICH WOULD HELP SHIFT THE WINDS BRIEFLY TO NW/N
DURING THE DAY.
SBY HAS A T/TD SPREAD OF AROUND 3 DEGREES AND WITH RAIN HAVING
FALLEN LATE THURSDAY...THERE MAY BE SOME IFR/LIFR FOG THERE. AN
OVERCAST HIGH CEILING SHOULD LIMIT FOG FORMATION AT OTHER LOCATIONS
AND PRESENTLY NONE IS FORECAST AT THE OTHER TAF SITES. VCTS ALSO
INCLUDED AT SBY.
DRY CONDITIONS EXPECTED FOR MUCH OF THE MORNING...BUT AN UPPER
LEVEL SHORT WAVE MAY BRING A ROUND OF TSTMS LATE IN THE DAY OR
TONIGHT.
OUTLOOK...THUNDERSTORM CHANCES CONTINUE INTO SATURDAY WITH DRY
WEATHER FORECAST BEGINNING SUNDAY. MVFR/IFR DUE TO STRATUS OR FOG
WILL BE A POTENTIAL A FEW HOURS AROUND SUNRISE THROUGH SUNDAY
MORNING.
&&
.MARINE...
LOW PRESSURE FORMS ALONG A STATIONARY BOUNDARY THAT IS CURRENTLY
POSITIONED OVER THE EASTERN PORTIONS OF THE FORECAST AREA OVERNIGHT.
THIS WEAK AREA OF LOW PRESSURE WILL MOVE OFF THE COAST FRIDAY AFTN.
EARLY SAT MORNING...HIGH PRESSURE NOSES SOUTH FROM THE NORTHEASTERN
US CAUSING A BACKDOOR COLD FRONT TO MOVE THROUGH THE AREA. ENERGY
STREAMING SE WILL HELP FORM AN AREA OF LOW PRESSURE OFF THE CAROLINA
COAST. THIS SYNOPTIC SETUP WILL ENHANCE THE PRESSURE GRADIENT ACROSS
THE WATERS CAUSING NEAR SCA WIND GUST OVER THE BAY(18-20KT) AND THE
COASTAL WATERS(23-25KT) ON SATURDAY. DUE TO THE WIND DIRECTION AND
FETCH...EXPECT WAVES TO BUILD TO 4-6FT ACROSS MOST OF THE COASTAL
WATERS LASTING EARLY SATURDAY THROUGH MONDAY NIGHT. HIGH PRESSURE
BEGINS TO POSITION OVER THE AREA BY TUESDAY BUT LOW PRESSURE
EMERGING FROM THE SOUTH MAY HELP TO MAINTAIN THE PRESSURE GRADIENT
AND ONSHORE FLOW THROUGH WED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ/JAO
SHORT TERM...AJZ/ALB
LONG TERM...DAP
AVIATION...MAS/LSA
MARINE...DAP
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1146 PM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 405 PM EDT SAT AUG 23 2014
HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR THE
MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT THAT
WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 405 PM EDT SAT AUG 23 2014
SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES ROUGHLY FROM EASTERN WISCONSIN UP THROUGH CENTRAL
UPPER MICHIGAN...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS
THE NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS MISSOURI INTO
THE OHIO RIVER VALLEY. ELEVATED WARM FRONT AND THETA-E PLUME
HAS SPREAD NORTHWARD ACROSS THE MIDWEST INTO THE LOWER GREAT
LAKES AND CONTINUES TO BE THE MAIN WEATHER FOCUS WITH YET ANOTHER
ROUND OF CONVECTION WORKING ACROSS THE MIDWEST THIS AFTERNOON.
ACROSS THE NRN GREAT LAKES...WEAK HIGH PRESSURE IS DRAPED ACROSS
NRN MICHIGAN. BUT...SUBTLE LOW-MID LEVEL TROUGH AXIS ANALYZED
ACROSS WESTERN/CENTRAL UPPER MICHIGAN ALONG NE FRINGE OF DEEPER
MOISTURE GRADIENT...WHERE RUC ANALYSIS CONTINUES TO DEPICT A
STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM NRN LAKE
MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS HAS/IS GENERATING
A BAND OF SHOWERS UP THROUGH THAT AREA PARTICULARLY AROUND THE
ESCANABA AREA (TERRAIN INFLUENCED) TRYING TO BLEED ACROSS NRN LAKE
MICHIGAN ALTHOUGH PRECIP APPEARS TO FINALLY BE WINDING DOWN. SOME
HEATING INDUCED CONVECTION ALSO ONGOING IN NE WISCONSIN WITHIN THE
BETTER MOISTURE FIELD. ACROSS NRN LOWER MICHIGAN...STUBBORN LAKE
STRATUS IN EASTERN UPPER AND NE LOWER MICHIGAN HAS MOSTLY MIXED
OUT INTO A FLAT CU FIELD. NO SIGNS OF ANY PRECIP. BUT SOLID LAKE
STRATUS REMAINS LOCKED ACROSS WESTERN LAKE HURON INTO THE
STRAITS...SIGNS OF THINGS TO COME I THINK.
TONIGHT...NO PRECIP AS MAIN FOCUS WILL REMAIN WEST-THROUGH-SOUTH OF
NRN MICHIGAN. WILL ENJOY A FEW HOURS OF CLR TO PARTLY CLOUDY SKIES
THIS EVENING AS HEATING INDUCE CU/STCU DECK FADES AWAY. BUT WITH
PERSISTENT EASTERLY FLOW JUST OFF THE DECK...VEERING SOUTHEAST
OVERNIGHT...SUSPECT MARINE LAYER/LAKE STRATUS AND FOG OUT ACROSS
LAKE HURON WILL ONCE AGAIN GET SCOOPED INTO EASTERN UPPER MICHIGAN
AND NORTHEAST LOWER MICHIGAN DURING THE OVERNIGHT HOURS. HAVE
TAILORED THE FORECAST THAT WAY ALONG WITH PATCHY TO AREAS OF FOG
OVERNIGHT. A REPEAT ON TEMPS WITH A BIT OF A MUGGY NIGHT
(RELATIVELY SPEAKING) AND LOWS IN THE UPPER 50S TO MIDDLE 60S.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 405 PM EDT SAT AUG 23 2014
...WARM START...COOLER FINISH TO THE UPCOMING WEEK...
HIGH IMPACT WEATHER POTENTIAL: MINIMAL. SOME THUNDER POTENTIAL AT
TIMES THIS WEEK.
PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: AMPLIFIED PATTERN SOO TALKED
ABOUT THE LAST SEVERAL DAYS LOOKS TO REACH MATURATION SUNDAY...WHEN
MOST IMPRESSIVE RIDGE AXIS/HEAT DOME OF THIS SUMMER BUILDS DIRECTLY
OVERHEAD AND UP INTO SOUTHEAST CANADA. WESTERN TROUGHING
CONTINUES...WITH LEAD EJECTING RATHER ROBUST SHORTWAVE LOOKING TO
PUT A KIBOSH ON FURTHER RIDGE AMPLIFICATION HEADING INTO THE START OF
NEXT WORK WEEK. PATTERN THERE-ON-AFTER LOOKS TO BECOME AN
INCREASINGLY FLATTER ONE AS STRONGEST CORES OF UPPER LEVEL JET ENERGY
SLICE WEST/EAST ACROSS SOUTHERN CANADA. A CHANGEABLE PATTERN FOR
SURE...AND ONE THAT SIMPLE FORCES ANOTHER EXTENDED STRETCH OF LOW
CONFIDENCE SHOWER AND STORM FORECAST EVOLUTION.
PRIMARY FORECAST CONCERNS/CHALLENGES: JUST HOW WARM TO GO
SUNDAY/MONDAY AND ADDRESSING WHAT INITIALLY LOOKS TO BE MULTI-PERIOD
SHOWER AND THUNDERSTORM CHANCES RIGHT THROUGH THE WEEK.
DETAILS: TAKE TODAY`S WEATHER...TACK ON A FEW DEGREES...SUNDAYS
WEATHER DONE! MORE SIGNIFICANT CHANGES TAKE PLACE MONDAY AS RIDGE
APEX PUSHES EAST AND EARLIER MENTIONED SHORTWAVE PUNCHES UP INTO SOUTH
CENTRAL CANADA. SOUTHWEST FLOW RAMPS UP IN RESPONSE...DRIVING A GOOD
CHUNK OF CURRENT SOUTHERN PLAINS HEAT DOME ALONG WITH IT. H8 TEMPS
MAKE A RUN INTO THE UPPER TEENS...READINGS NOT YET SEEN AROUND THESE
PARTS THIS SUMMER. INCREASING PRESSURE GRADIENT ON FRONT SIDE OF
APPROACHING/ALBEIT STEADILY DECAYING/COLD FRONT SHOULD ONLY HELP THE
SURFACE WARMING CAUSE. TEMPERATURES WELL INTO THE 80S A SURE BET FOR
AREAS SOUTH OF THE BIG BRIDGE...AND NOT OUT OF THE REALM OF
POSSIBILITY A FEW FAVORED DOWNSLOPE AREAS OF NORTHEAST LOWER MAKE A
RUN A 90. NOW...THAT SAME FRONT MAY BRING A SHOWER AND STORM THREAT
ALONG WITH IT. DEFINITELY NOT ENTIRELY SOLD ON THIS IDEA GIVEN FAR
REMOVED MID LEVEL SUPPORT AND QUICKLY DECAYING FORCED SURFACE
CONVERGENCE. ATMOSPHERE ALSO HAS THE LOOK OF BEING RATHER
CAPED...WITH NOTED H8 WARM NOSE. WHILE OVERALL AIRMASS BECOMES
INCREASINGLY MOIST...SET-UP SCREAMS OF DECENT LOW LEVEL MIXING OUT
OF MOISTURE...AND STARTING TO WONDER IF PROGGED UPPER 60 DEWPOINTS
ARE SEVERAL DEGREES TOO HIGH. NO DOUBT ABOVE LEAVES PLENTY OF
OPPORTUNITY FOR A DRY LATE MONDAY FRONTAL PASSAGE. INHERITED LOW
CHANCES WILL DO FOR NOW...BUT TRULY BELIEVE MANY WILL SEE
LITTLE...IF ANY...RAIN.
SAID FRONT LOOKS TO SIGNIFICANTLY SLOW ITS SOUTH PROGRESS MONDAY
NIGHT THROUGH TUESDAY NIGHT AS IT BECOMES INCREASINGLY ALIGNED WITH
DEEP LAYER WESTERLY FLOW. JUST WHERE IT STALLS OUT IS OPEN TO PLENTY
OF DEBATE...BUT GIVEN BREADTH OF PREFRONTAL WARMING AND TOTAL
DETACHMENT OF ANY MID LEVEL SUPPORT...KINDA FEEL IT MAY STRUGGLE TO
CLEAR OUR SOUTHERN COUNTIES UNTIL SOMETIME TUESDAY NIGHT. NOW...THAT
LEADS TO A TRICKY TEMPERATURE AND SHOWER FORECAST RIGHT THROUGH MID
WEEK. AS FOR TEMPERATURES...TUESDAY HAS THE POTENTIAL TO BE
DOWNRIGHT WARM...ESPECIALLY FOR AREAS NEAR SAGINAW BAY...WHERE
TEMPERATURES MAY ONCE AGAIN REACH INTO THE MID AND UPPER 80S. COOLER
AIR ARRIVES WEDNESDAY...WITH HIGHS MOSTLY IN THE 70S (ALL DEPENDENT
ON THAT WHOLE FRONTAL TIMING THING OF COURSE). NEARLY ALL GUIDANCE
REMAINS STEADFAST ON ADDITIONAL SHOWER/STORM DEVELOPMENT ALONG AND
NORTH OF THE SURFACE FRONT AS WEAK MID LEVEL IMPULSES RIDE ALONG IT
MONDAY NIGHT RIGHT INTO WEDNESDAY. ANY DECENT SUPPORT IS FAR FROM
CERTAIN...AND JUST NOT BUYING THIS WET LOOK IN GUIDANCE. MUCH LIKE
MONDAY...LOWER POPS THE WAY TO GO FOR NOW...WITH PLENTY OF TIME TO
WORK ON BETTER TEMPORAL AND SPATIAL RESOLUTION OF SHOWER/STORM
CHANCES IN THE COMING DAYS.
SOME HINTS WHAT IS LEFT OF WESTERN TROUGHING GETS SHUNTED EAST LATE
IN THE WEEK...FORCING FRONT BACK NORTH AND DRUMMING UP ADDITIONAL
RAIN CHANCES TO START NEXT WEEKEND. TIMING WILL CHANGE...AND A
SIMPLE CONSENSUS BLEND APPROACH WILL BE UTILIZED FOR NOW....WHICH
INDEED HOLDS OFF NEXT MENTION FOR SHOWERS/STORMS UNTIL FRIDAY NIGHT
AND SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1145 PM EDT SAT AUG 23 2014
LOW STRATUS AND FOG WILL AGAIN DEVELOP OVERNIGHT INTO EARLY
SUNDAY...ESPECIALLY FOR FAR NRN AND NE LWR MICHIGAN THANKS TO
LIGHT EASTERLY FLOW OFF OF LAKE HURON. CONDITIONS WILL DETERIORATE
TO MVFR/IFR...WITH THE LOWEST CIGS AND VSBYS AT APN AND PLN WHERE
VSBYS WILL DROP AOB 1SM. VFR CONDITIONS WILL RETURN BY MID MORNING
AS THE STRATUS AND FOG MIX OUT.
&&
.MARINE...
ISSUED AT 405 PM EDT SAT AUG 23 2014
ABUNDANT MARINE STRATUS AND FOG WILL CONTINUE TO IMPACT THE NEARSHORE
AREAS OF NRN LAKE HURON INTO THE SAINT MARYS RIVER SYSTEM...TONIGHT
INTO SUNDAY BEFORE STRONGER SOUTHERLY WINDS DEVELOP LATER SUNDAY
INTO MONDAY AND FINALLY SCOURS OUT THE STRATUS/FOG.
OTHERWISE...LIGHT EASTERLY WINDS TONIGHT WILL VEER MORE SOUTHEASTERLY
THEN SOUTH ON SUNDAY...INCREASING SUNDAY NIGHT INTO MONDAY. MAY
DEVELOP ENOUGH GUSTINESS TO WARRANT SMALL CRAFT ADVISORIES FOR
PARTS OF NRN LAKE MICHIGAN BY MONDAY MORNING...ALTHOUGH LAKE
STABILITY MAY KEEP WINDS/WAVES IN CHECK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...AM
SHORT TERM...ADAM
LONG TERM...MSB
AVIATION...MR
MARINE...ADAM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
717 PM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 405 PM EDT SAT AUG 23 2014
HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR THE
MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT THAT
WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 405 PM EDT SAT AUG 23 2014
SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES ROUGHLY FROM EASTERN WISCONSIN UP THROUGH CENTRAL
UPPER MICHIGAN...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS
THE NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS MISSOURI INTO
THE OHIO RIVER VALLEY. ELEVATED WARM FRONT AND THETA-E PLUME
HAS SPREAD NORTHWARD ACROSS THE MIDWEST INTO THE LOWER GREAT
LAKES AND CONTINUES TO BE THE MAIN WEATHER FOCUS WITH YET ANOTHER
ROUND OF CONVECTION WORKING ACROSS THE MIDWEST THIS AFTERNOON.
ACROSS THE NRN GREAT LAKES...WEAK HIGH PRESSURE IS DRAPED ACROSS
NRN MICHIGAN. BUT...SUBTLE LOW-MID LEVEL TROUGH AXIS ANALYZED
ACROSS WESTERN/CENTRAL UPPER MICHIGAN ALONG NE FRINGE OF DEEPER
MOISTURE GRADIENT...WHERE RUC ANALYSIS CONTINUES TO DEPICT A
STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM NRN LAKE
MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS HAS/IS GENERATING
A BAND OF SHOWERS UP THROUGH THAT AREA PARTICULARLY AROUND THE
ESCANABA AREA (TERRAIN INFLUENCED) TRYING TO BLEED ACROSS NRN LAKE
MICHIGAN ALTHOUGH PRECIP APPEARS TO FINALLY BE WINDING DOWN. SOME
HEATING INDUCED CONVECTION ALSO ONGOING IN NE WISCONSIN WITHIN THE
BETTER MOISTURE FIELD. ACROSS NRN LOWER MICHIGAN...STUBBORN LAKE
STRATUS IN EASTERN UPPER AND NE LOWER MICHIGAN HAS MOSTLY MIXED
OUT INTO A FLAT CU FIELD. NO SIGNS OF ANY PRECIP. BUT SOLID LAKE
STRATUS REMAINS LOCKED ACROSS WESTERN LAKE HURON INTO THE
STRAITS...SIGNS OF THINGS TO COME I THINK.
TONIGHT...NO PRECIP AS MAIN FOCUS WILL REMAIN WEST-THROUGH-SOUTH OF
NRN MICHIGAN. WILL ENJOY A FEW HOURS OF CLR TO PARTLY CLOUDY SKIES
THIS EVENING AS HEATING INDUCE CU/STCU DECK FADES AWAY. BUT WITH
PERSISTENT EASTERLY FLOW JUST OFF THE DECK...VEERING SOUTHEAST
OVERNIGHT...SUSPECT MARINE LAYER/LAKE STRATUS AND FOG OUT ACROSS
LAKE HURON WILL ONCE AGAIN GET SCOOPED INTO EASTERN UPPER MICHIGAN
AND NORTHEAST LOWER MICHIGAN DURING THE OVERNIGHT HOURS. HAVE
TAILORED THE FORECAST THAT WAY ALONG WITH PATCHY TO AREAS OF FOG
OVERNIGHT. A REPEAT ON TEMPS WITH A BIT OF A MUGGY NIGHT
(RELATIVELY SPEAKING) AND LOWS IN THE UPPER 50S TO MIDDLE 60S.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 405 PM EDT SAT AUG 23 2014
...WARM START...COOLER FINISH TO THE UPCOMING WEEK...
HIGH IMPACT WEATHER POTENTIAL: MINIMAL. SOME THUNDER POTENTIAL AT
TIMES THIS WEEK.
PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: AMPLIFIED PATTERN SOO TALKED
ABOUT THE LAST SEVERAL DAYS LOOKS TO REACH MATURATION SUNDAY...WHEN
MOST IMPRESSIVE RIDGE AXIS/HEAT DOME OF THIS SUMMER BUILDS DIRECTLY
OVERHEAD AND UP INTO SOUTHEAST CANADA. WESTERN TROUGHING
CONTINUES...WITH LEAD EJECTING RATHER ROBUST SHORTWAVE LOOKING TO
PUT A KIBOSH ON FURTHER RIDGE AMPLIFICATION HEADING INTO THE START OF
NEXT WORK WEEK. PATTERN THERE-ON-AFTER LOOKS TO BECOME AN
INCREASINGLY FLATTER ONE AS STRONGEST CORES OF UPPER LEVEL JET ENERGY
SLICE WEST/EAST ACROSS SOUTHERN CANADA. A CHANGEABLE PATTERN FOR
SURE...AND ONE THAT SIMPLE FORCES ANOTHER EXTENDED STRETCH OF LOW
CONFIDENCE SHOWER AND STORM FORECAST EVOLUTION.
PRIMARY FORECAST CONCERNS/CHALLENGES: JUST HOW WARM TO GO
SUNDAY/MONDAY AND ADDRESSING WHAT INITIALLY LOOKS TO BE MULTI-PERIOD
SHOWER AND THUNDERSTORM CHANCES RIGHT THROUGH THE WEEK.
DETAILS: TAKE TODAY`S WEATHER...TACK ON A FEW DEGREES...SUNDAYS
WEATHER DONE! MORE SIGNIFICANT CHANGES TAKE PLACE MONDAY AS RIDGE
APEX PUSHES EAST AND EARLIER MENTIONED SHORTWAVE PUNCHES UP INTO SOUTH
CENTRAL CANADA. SOUTHWEST FLOW RAMPS UP IN RESPONSE...DRIVING A GOOD
CHUNK OF CURRENT SOUTHERN PLAINS HEAT DOME ALONG WITH IT. H8 TEMPS
MAKE A RUN INTO THE UPPER TEENS...READINGS NOT YET SEEN AROUND THESE
PARTS THIS SUMMER. INCREASING PRESSURE GRADIENT ON FRONT SIDE OF
APPROACHING/ALBEIT STEADILY DECAYING/COLD FRONT SHOULD ONLY HELP THE
SURFACE WARMING CAUSE. TEMPERATURES WELL INTO THE 80S A SURE BET FOR
AREAS SOUTH OF THE BIG BRIDGE...AND NOT OUT OF THE REALM OF
POSSIBILITY A FEW FAVORED DOWNSLOPE AREAS OF NORTHEAST LOWER MAKE A
RUN A 90. NOW...THAT SAME FRONT MAY BRING A SHOWER AND STORM THREAT
ALONG WITH IT. DEFINITELY NOT ENTIRELY SOLD ON THIS IDEA GIVEN FAR
REMOVED MID LEVEL SUPPORT AND QUICKLY DECAYING FORCED SURFACE
CONVERGENCE. ATMOSPHERE ALSO HAS THE LOOK OF BEING RATHER
CAPED...WITH NOTED H8 WARM NOSE. WHILE OVERALL AIRMASS BECOMES
INCREASINGLY MOIST...SET-UP SCREAMS OF DECENT LOW LEVEL MIXING OUT
OF MOISTURE...AND STARTING TO WONDER IF PROGGED UPPER 60 DEWPOINTS
ARE SEVERAL DEGREES TOO HIGH. NO DOUBT ABOVE LEAVES PLENTY OF
OPPORTUNITY FOR A DRY LATE MONDAY FRONTAL PASSAGE. INHERITED LOW
CHANCES WILL DO FOR NOW...BUT TRULY BELIEVE MANY WILL SEE
LITTLE...IF ANY...RAIN.
SAID FRONT LOOKS TO SIGNIFICANTLY SLOW ITS SOUTH PROGRESS MONDAY
NIGHT THROUGH TUESDAY NIGHT AS IT BECOMES INCREASINGLY ALIGNED WITH
DEEP LAYER WESTERLY FLOW. JUST WHERE IT STALLS OUT IS OPEN TO PLENTY
OF DEBATE...BUT GIVEN BREADTH OF PREFRONTAL WARMING AND TOTAL
DETACHMENT OF ANY MID LEVEL SUPPORT...KINDA FEEL IT MAY STRUGGLE TO
CLEAR OUR SOUTHERN COUNTIES UNTIL SOMETIME TUESDAY NIGHT. NOW...THAT
LEADS TO A TRICKY TEMPERATURE AND SHOWER FORECAST RIGHT THROUGH MID
WEEK. AS FOR TEMPERATURES...TUESDAY HAS THE POTENTIAL TO BE
DOWNRIGHT WARM...ESPECIALLY FOR AREAS NEAR SAGINAW BAY...WHERE
TEMPERATURES MAY ONCE AGAIN REACH INTO THE MID AND UPPER 80S. COOLER
AIR ARRIVES WEDNESDAY...WITH HIGHS MOSTLY IN THE 70S (ALL DEPENDENT
ON THAT WHOLE FRONTAL TIMING THING OF COURSE). NEARLY ALL GUIDANCE
REMAINS STEADFAST ON ADDITIONAL SHOWER/STORM DEVELOPMENT ALONG AND
NORTH OF THE SURFACE FRONT AS WEAK MID LEVEL IMPULSES RIDE ALONG IT
MONDAY NIGHT RIGHT INTO WEDNESDAY. ANY DECENT SUPPORT IS FAR FROM
CERTAIN...AND JUST NOT BUYING THIS WET LOOK IN GUIDANCE. MUCH LIKE
MONDAY...LOWER POPS THE WAY TO GO FOR NOW...WITH PLENTY OF TIME TO
WORK ON BETTER TEMPORAL AND SPATIAL RESOLUTION OF SHOWER/STORM
CHANCES IN THE COMING DAYS.
SOME HINTS WHAT IS LEFT OF WESTERN TROUGHING GETS SHUNTED EAST LATE
IN THE WEEK...FORCING FRONT BACK NORTH AND DRUMMING UP ADDITIONAL
RAIN CHANCES TO START NEXT WEEKEND. TIMING WILL CHANGE...AND A
SIMPLE CONSENSUS BLEND APPROACH WILL BE UTILIZED FOR NOW....WHICH
INDEED HOLDS OFF NEXT MENTION FOR SHOWERS/STORMS UNTIL FRIDAY NIGHT
AND SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 717 PM EDT SAT AUG 23 2014
LOW STRATUS AND FOG WILL AGAIN DEVELOP LATER THIS EVENING...
OVERNIGHT AND EARLY SUNDAY...ESPECIALLY FOR FAR NRN AND NE LWR
MICHIGAN THANKS TO LIGHT EASTERLY FLOW OFF OF LAKE HURON.
CONDITIONS WILL DETERIORATE TO MVFR/IFR...WITH THE LOWEST CIGS AND
VSBYS AT APN AND PLN WHERE VSBYS WILL DROP AOB 1SM. VFR CONDITIONS
WILL RETURN BY MID MORNING SUNDAY AS THE STRATUS AND FOG MIX OUT.
&&
.MARINE...
ISSUED AT 405 PM EDT SAT AUG 23 2014
ABUNDANT MARINE STRATUS AND FOG WILL CONTINUE TO IMPACT THE NEARSHORE
AREAS OF NRN LAKE HURON INTO THE SAINT MARYS RIVER SYSTEM...TONIGHT
INTO SUNDAY BEFORE STRONGER SOUTHERLY WINDS DEVELOP LATER SUNDAY
INTO MONDAY AND FINALLY SCOURS OUT THE STRATUS/FOG.
OTHERWISE...LIGHT EASTERLY WINDS TONIGHT WILL VEER MORE SOUTHEASTERLY
THEN SOUTH ON SUNDAY...INCREASING SUNDAY NIGHT INTO MONDAY. MAY
DEVELOP ENOUGH GUSTINESS TO WARRANT SMALL CRAFT ADVISORIES FOR
PARTS OF NRN LAKE MICHIGAN BY MONDAY MORNING...ALTHOUGH LAKE
STABILITY MAY KEEP WINDS/WAVES IN CHECK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...AM
SHORT TERM...ADAM
LONG TERM...MSB
AVIATION...MR
MARINE...ADAM
UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.
UPDATE ISSUED AT 959 AM CDT FRI AUG 22 2014
ADDED PATCHY DRIZZLE TO THE FORECAST THROUGH THE DAY AND KEPT
FOG...LOCALLY DENSE MENTIONED THROUGH THE AFTERNOON AROUND THE
TWIN PORTS...ESPECIALLY ALONG THE HILLSIDE AREA. LAKE BREEZE OFF
LS WILL CONTINUE TODAY AND INTO THE WEEKEND WITH COOL
TEMPERATURES...LOW CLOUDS AND PATCHY FOG AND DZ. REST OF THE
FORECAST LOOKS ON TRACK AT THIS TIME.
UPDATE ISSUED AT 650 AM CDT FRI AUG 22 2014
UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI AUG 22 2014
MID LVL RIDGING CONTINUES OVER THE CWA EARLY THIS MORNING AS A
BROAD AREA OF WEAK LOW PRESSURE SHIFTS SLOW EAST UNDERNEATH.
LATEST RUC SHOWS A 925 LOW OVER WCTRL WISC WITH AN INVERTED SHEAR
AXIS EXTENDING NORTHWEST TOWARDS KBJI AND KROX. THIS IS FOLLOWED
BY A COLD FRONT STRETCHING FROM ERN MANITOBA SOUTH TO CENTRAL
SODAK. MAIN STORY OVER CWA THIS MORNING IS TRAPPED MOIST LAYER...
ABOUT 5K FT IN DEPTH...UNDERNEATH SUBSIDENCE INVERSION. BR/FG AND
EVEN SOME DRIZZLE IS OCCURRING IN MANY AREAS. A FEW CONVECTIVE
CELLS HAVE TRIED TO DEVELOP OVER SERN WISC ZONES IN AN AREA OF LOW
LVL THETAE RIDGE AXIS. LIMITED INSTABILITY HAS ALLOWED FAIRLY
SHORT TEMPORAL NATURE TO DEVELOPMENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
TODAY...FCST MDL SNDGS SUGGEST IT MAY TAKE QUITE SOME TIME TO
DISSIPATE THE CANOPY OF STRATUS AND BR ACROSS THE REGION. COND
PRES DEFICITS SHOW A TREND TO DIMINISHING BR BY 14/15Z....THEN A
RELATIVELY SATURATED CLOUD LAYER FINALLY BREAKING AFTER 2PM.
PRECIP CHC SEEMS QUITE LIMITED BY RIDGING ALOFT AND LACK OF LOW
LVL FOCUS FOR CONVERGENCE. THE GREATEST OPPORTUNITY MAY ARISE IN
THE AFTERNOON AHEAD OF APPROACHING FRONTAL BDRY PUSHING TOWARDS
NWRN CWA. MID LVL WARMTH WILL LIMIT MUCH DEVELOPMENT UNTIL
AFTERNOON AS 70H THERMAL COOLING COMMENCES OVER WRN CWA.
TONIGHT...MID LVL RIDGE AMPLIFIES OVERHEAD TONIGHT IN RESPONSE TO
UPSTREAM STRENGTHENING OF TROF OVER ROCKIES. FRONTAL BDRY WILL
STALL NORTH AND WEST OF CWA HOWEVER ITS ASSOCIATED PREFRONTAL
THETAE RIDGE WILL BE NEARBY. ALTHOUGH THE DRY FORECAST WAS CARRIED
OVER FROM PREVIOUS FCSTR...WILL NEED TO WATCH FOR SOME DEVELOPMENT
OF CONVECTION MAKING IT INTO NWRN CWA TONIGHT.
TOMORROW...HEIGHT FALLS MOVE INTO WRN HIGH PLAINS WITH SFC LOW
ORGANIZING OVER SODAK. A SWRLY MID LVL FLOW WILL BEGIN OVER THE
CWA AS THE RIDGE AXIS SHIFTS EAST. SFC HIGH PRESSURE WILL INCREASE
OVER LAKE SUPERIOR WITH DISTINCT ONSHORE COMPONENT TO BDRY LYR
WIND. TOUGH FCST FOR PRECIP AS MAIN FOCUS APPEARS TO BE SHAPING UP
OVER THE WRN CWA BY LATE IN THE DAY. CLOUDS/PRECIP FCST FOR NORTH
SHORE BASED ON A COMBINATION OF TERRAIN LIFT AND A GRADUAL
DEEPENING OF SYNOPTIC SCALE MOIST LAYER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
THE STRONG SURFACE LOW WILL MOVE NORTH ALONG THE WESTERN MINNESOTA
BORDER SATURDAY NIGHT AND SUNDAY MORNING...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY THE THE WESTERN PORTIONS OF THE
FORECAST AREA OVERNIGHT. HAVE GONE AHEAD AN INCREASED POPS TO
CATEGORICAL THERE...WITH HIGH END CHANCE TO LIKELY POPS ELSEWHERE AS
THE WARM FRONT MOVES NORTH ACROSS THE REGION. MODELS ARE GETTING
CLOSE ENOUGH TOGETHER TO HAVE A FAIRLY HIGH CONFIDENCE...THOUGH THE
TRACK IS STILL SOMEWHAT PROBLEMATIC. WITH THE SURFACE LOW MOVING
NORTHEAST OF THE REGION SUNDAY AND SUNDAY NIGHT....A COLD FRONT IS
DRAGGED THROUGH THE AREA. DEPENDING ON THE MODEL...THE TIMING
DIFFERS...BUT EITHER WAY WE ARE LOOKING AT MORE CHANCE TO LIKELY
POPS. THE ECMWF...WHICH IS FARTHER WEST THAN THE GFS IMPLIES WE MAY
HAVE SOME POTENTIAL FOR SEVERE STORMS...AS THE FRONT COMES THROUGH
LATER AND ALLOWS FOR HEATING DURING THE DAY TO BUILD INSTABILITY
AHEAD OF IT. WILL HAVE TO WATCH THIS CAREFULLY IN THE NEXT FEW
DAYS. HAVE GONE WITH SOME FAIRLY WARM HIGH TEMPS ON SUNDAY...BUT IF
THE ECMWF WORKS OUT...THESE WILL NEED TO BE RAISED. THIS STORM
LINGERS OVER WESTERN ONTARIO FOR MONDAY BEFORE MOVING OFF TO THE
NORTHEAST MONDAY AFTERNOON AND NIGHT...KEEPING SOME CHANCE POPS
GOING OVER THE AREA BOTH PERIODS WITH COOLER TEMPERATURES.
OUR NEXT SIGNIFICANT STORM SYSTEM COMES BY ON TUESDAY THROUGH
WEDNESDAY. MODELS ARE VARYING SIGNIFICANTLY BY THIS POINT...WITH
THE THE GFS BRINGING AN AREA OF MODERATE TO HEAVY RAIN ACROSS THE
FORECAST AREA...AND THE ECMWF KEEPING IT FARTHER SOUTH AND DRIER FOR
US. FOR NOW HAVE GONE WITH A BLEND APPROACH WITH SOME CHANCE POPS
AND WE WILL HAVE TO REVISIT WITH LATER FORECASTS. A STRONG SURFACE
RIDGE BUILDS INTO THE AREA FOR WEDNESDAY NIGHT AND
THURSDAY....BRINGING COOLER TEMPERATURES AND HOPEFULLY A BIT MORE
SUNSHINE TO THE REGION. LOWS BY WEDNESDAY NIGHT AND THURSDAY NIGHT
MAY DIP INTO THE 40S AGAIN FOR PORTIONS OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1252 PM CDT FRI AUG 22 2014
A MOIST EASTERLY FLOW WILL CONTINUE THROUGHOUT THE TAF PERIOD.
WE SHOULD START THE DAY LARGELY IN THE IFR/LIFR RANGE NEAR LAKE
SUPERIOR...AND MVFR TO IFR AT INLAND LOCATIONS. SOME IMPROVEMENT
IS POSSIBLE DURING THE AFTERNOON BUT WE SHOULD SEE CONDITIONS GO
RIGHT BACK TO LOWER VALUES OVERNIGHT. WE ARE EXPECTED LARGE SCALE
IFR/LIFR AND EVEN SOME VLIFR NEAR LAKE SUPERIOR OVERNIGHT AND
LINGERING INTO SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 68 60 70 61 / 30 10 20 60
INL 74 57 76 58 / 20 10 30 70
BRD 78 61 75 64 / 10 20 50 70
HYR 76 61 78 64 / 20 20 40 60
ASX 71 59 73 62 / 30 20 20 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR MNZ037.
WI...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR WIZ001.
LS...NONE.
&&
$$
UPDATE...DAP
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1003 AM CDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 959 AM CDT FRI AUG 22 2014
ADDED PATCHY DRIZZLE TO THE FORECAST THROUGH THE DAY AND KEPT
FOG...LOCALLY DENSE MENTIONED THROUGH THE AFTERNOON AROUND THE
TWIN PORTS...ESPECIALLY ALONG THE HILLSIDE AREA. LAKE BREEZE OFF
LS WILL CONTINUE TODAY AND INTO THE WEEKEND WITH COOL
TEMPERATURES...LOW CLOUDS AND PATCHY FOG AND DZ. REST OF THE
FORECAST LOOKS ON TRACK AT THIS TIME.
UPDATE ISSUED AT 650 AM CDT FRI AUG 22 2014
UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI AUG 22 2014
MID LVL RIDGING CONTINUES OVER THE CWA EARLY THIS MORNING AS A
BROAD AREA OF WEAK LOW PRESSURE SHIFTS SLOW EAST UNDERNEATH.
LATEST RUC SHOWS A 925 LOW OVER WCTRL WISC WITH AN INVERTED SHEAR
AXIS EXTENDING NORTHWEST TOWARDS KBJI AND KROX. THIS IS FOLLOWED
BY A COLD FRONT STRETCHING FROM ERN MANITOBA SOUTH TO CENTRAL
SODAK. MAIN STORY OVER CWA THIS MORNING IS TRAPPED MOIST LAYER...
ABOUT 5K FT IN DEPTH...UNDERNEATH SUBSIDENCE INVERSION. BR/FG AND
EVEN SOME DRIZZLE IS OCCURRING IN MANY AREAS. A FEW CONVECTIVE
CELLS HAVE TRIED TO DEVELOP OVER SERN WISC ZONES IN AN AREA OF LOW
LVL THETAE RIDGE AXIS. LIMITED INSTABILITY HAS ALLOWED FAIRLY
SHORT TEMPORAL NATURE TO DEVELOPMENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
TODAY...FCST MDL SNDGS SUGGEST IT MAY TAKE QUITE SOME TIME TO
DISSIPATE THE CANOPY OF STRATUS AND BR ACROSS THE REGION. COND
PRES DEFICITS SHOW A TREND TO DIMINISHING BR BY 14/15Z....THEN A
RELATIVELY SATURATED CLOUD LAYER FINALLY BREAKING AFTER 2PM.
PRECIP CHC SEEMS QUITE LIMITED BY RIDGING ALOFT AND LACK OF LOW
LVL FOCUS FOR CONVERGENCE. THE GREATEST OPPORTUNITY MAY ARISE IN
THE AFTERNOON AHEAD OF APPROACHING FRONTAL BDRY PUSHING TOWARDS
NWRN CWA. MID LVL WARMTH WILL LIMIT MUCH DEVELOPMENT UNTIL
AFTERNOON AS 70H THERMAL COOLING COMMENCES OVER WRN CWA.
TONIGHT...MID LVL RIDGE AMPLIFIES OVERHEAD TONIGHT IN RESPONSE TO
UPSTREAM STRENGTHENING OF TROF OVER ROCKIES. FRONTAL BDRY WILL
STALL NORTH AND WEST OF CWA HOWEVER ITS ASSOCIATED PREFRONTAL
THETAE RIDGE WILL BE NEARBY. ALTHOUGH THE DRY FORECAST WAS CARRIED
OVER FROM PREVIOUS FCSTR...WILL NEED TO WATCH FOR SOME DEVELOPMENT
OF CONVECTION MAKING IT INTO NWRN CWA TONIGHT.
TOMORROW...HEIGHT FALLS MOVE INTO WRN HIGH PLAINS WITH SFC LOW
ORGANIZING OVER SODAK. A SWRLY MID LVL FLOW WILL BEGIN OVER THE
CWA AS THE RIDGE AXIS SHIFTS EAST. SFC HIGH PRESSURE WILL INCREASE
OVER LAKE SUPERIOR WITH DISTINCT ONSHORE COMPONENT TO BDRY LYR
WIND. TOUGH FCST FOR PRECIP AS MAIN FOCUS APPEARS TO BE SHAPING UP
OVER THE WRN CWA BY LATE IN THE DAY. CLOUDS/PRECIP FCST FOR NORTH
SHORE BASED ON A COMBINATION OF TERRAIN LIFT AND A GRADUAL
DEEPENING OF SYNOPTIC SCALE MOIST LAYER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
THE STRONG SURFACE LOW WILL MOVE NORTH ALONG THE WESTERN MINNESOTA
BORDER SATURDAY NIGHT AND SUNDAY MORNING...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY THE THE WESTERN PORTIONS OF THE
FORECAST AREA OVERNIGHT. HAVE GONE AHEAD AN INCREASED POPS TO
CATEGORICAL THERE...WITH HIGH END CHANCE TO LIKELY POPS ELSEWHERE AS
THE WARM FRONT MOVES NORTH ACROSS THE REGION. MODELS ARE GETTING
CLOSE ENOUGH TOGETHER TO HAVE A FAIRLY HIGH CONFIDENCE...THOUGH THE
TRACK IS STILL SOMEWHAT PROBLEMATIC. WITH THE SURFACE LOW MOVING
NORTHEAST OF THE REGION SUNDAY AND SUNDAY NIGHT....A COLD FRONT IS
DRAGGED THROUGH THE AREA. DEPENDING ON THE MODEL...THE TIMING
DIFFERS...BUT EITHER WAY WE ARE LOOKING AT MORE CHANCE TO LIKELY
POPS. THE ECMWF...WHICH IS FARTHER WEST THAN THE GFS IMPLIES WE MAY
HAVE SOME POTENTIAL FOR SEVERE STORMS...AS THE FRONT COMES THROUGH
LATER AND ALLOWS FOR HEATING DURING THE DAY TO BUILD INSTABILITY
AHEAD OF IT. WILL HAVE TO WATCH THIS CAREFULLY IN THE NEXT FEW
DAYS. HAVE GONE WITH SOME FAIRLY WARM HIGH TEMPS ON SUNDAY...BUT IF
THE ECMWF WORKS OUT...THESE WILL NEED TO BE RAISED. THIS STORM
LINGERS OVER WESTERN ONTARIO FOR MONDAY BEFORE MOVING OFF TO THE
NORTHEAST MONDAY AFTERNOON AND NIGHT...KEEPING SOME CHANCE POPS
GOING OVER THE AREA BOTH PERIODS WITH COOLER TEMPERATURES.
OUR NEXT SIGNIFICANT STORM SYSTEM COMES BY ON TUESDAY THROUGH
WEDNESDAY. MODELS ARE VARYING SIGNIFICANTLY BY THIS POINT...WITH
THE THE GFS BRINGING AN AREA OF MODERATE TO HEAVY RAIN ACROSS THE
FORECAST AREA...AND THE ECMWF KEEPING IT FARTHER SOUTH AND DRIER FOR
US. FOR NOW HAVE GONE WITH A BLEND APPROACH WITH SOME CHANCE POPS
AND WE WILL HAVE TO REVISIT WITH LATER FORECASTS. A STRONG SURFACE
RIDGE BUILDS INTO THE AREA FOR WEDNESDAY NIGHT AND
THURSDAY....BRINGING COOLER TEMPERATURES AND HOPEFULLY A BIT MORE
SUNSHINE TO THE REGION. LOWS BY WEDNESDAY NIGHT AND THURSDAY NIGHT
MAY DIP INTO THE 40S AGAIN FOR PORTIONS OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 650 AM CDT FRI AUG 22 2014
WIDE RANGE OF CONDITIONS ACROSS THE TERMINALS THIS MORNING...WITH
LIFR FOR KDLH...KHYR AND KBRD WHERE NORTHEAST FLOW OFF LAKE
SUPERIOR HAS GENERATED STRATUS AND EVEN SOME LIFR VISIBILITIES IN
FOG. KHIB IS IFR WITH KINL AT VFR CIGS...THOUGH VFR VISIBILITIES
BOTH LOCATIONS. CIGS AND VISIBILITIES EXPECTED TO GRADUALLY
IMPROVE THROUGH 20Z TODAY...WITH MOST TERMINALS RETURNING TO AT
LEAST MVFR CIGS AND VFR VISIBILITIES. THIS EVENING CIGS AND
VISIBILITIES TO DETERIORATE AGAIN AFTER 02Z...LIKELY DROPPING TO
IFR/LIFR CIGS AND VISIBILITIES FOR SEVERAL HOURS OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 68 60 70 61 / 30 10 20 60
INL 74 57 76 58 / 20 10 30 70
BRD 78 61 75 64 / 10 20 50 70
HYR 76 61 78 64 / 20 20 40 60
ASX 71 59 73 62 / 30 20 20 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR MNZ037.
WI...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR WIZ001.
LS...NONE.
&&
$$
UPDATE...BJT
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
650 AM CDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 650 AM CDT FRI AUG 22 2014
UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI AUG 22 2014
MID LVL RIDGING CONTINUES OVER THE CWA EARLY THIS MORNING AS A
BROAD AREA OF WEAK LOW PRESSURE SHIFTS SLOW EAST UNDERNEATH.
LATEST RUC SHOWS A 925 LOW OVER WCTRL WISC WITH AN INVERTED SHEAR
AXIS EXTENDING NORTHWEST TOWARDS KBJI AND KROX. THIS IS FOLLOWED
BY A COLD FRONT STRETCHING FROM ERN MANITOBA SOUTH TO CENTRAL
SODAK. MAIN STORY OVER CWA THIS MORNING IS TRAPPED MOIST LAYER...
ABOUT 5K FT IN DEPTH...UNDERNEATH SUBSIDENCE INVERSION. BR/FG AND
EVEN SOME DRIZZLE IS OCCURRING IN MANY AREAS. A FEW CONVECTIVE
CELLS HAVE TRIED TO DEVELOP OVER SERN WISC ZONES IN AN AREA OF LOW
LVL THETAE RIDGE AXIS. LIMITED INSTABILITY HAS ALLOWED FAIRLY
SHORT TEMPORAL NATURE TO DEVELOPMENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
TODAY...FCST MDL SNDGS SUGGEST IT MAY TAKE QUITE SOME TIME TO
DISSIPATE THE CANOPY OF STRATUS AND BR ACROSS THE REGION. COND
PRES DEFICITS SHOW A TREND TO DIMINISHING BR BY 14/15Z....THEN A
RELATIVELY SATURATED CLOUD LAYER FINALLY BREAKING AFTER 2PM.
PRECIP CHC SEEMS QUITE LIMITED BY RIDGING ALOFT AND LACK OF LOW
LVL FOCUS FOR CONVERGENCE. THE GREATEST OPPORTUNITY MAY ARISE IN
THE AFTERNOON AHEAD OF APPROACHING FRONTAL BDRY PUSHING TOWARDS
NWRN CWA. MID LVL WARMTH WILL LIMIT MUCH DEVELOPMENT UNTIL
AFTERNOON AS 70H THERMAL COOLING COMMENCES OVER WRN CWA.
TONIGHT...MID LVL RIDGE AMPLIFIES OVERHEAD TONIGHT IN RESPONSE TO
UPSTREAM STRENGTHENING OF TROF OVER ROCKIES. FRONTAL BDRY WILL
STALL NORTH AND WEST OF CWA HOWEVER ITS ASSOCIATED PREFRONTAL
THETAE RIDGE WILL BE NEARBY. ALTHOUGH THE DRY FORECAST WAS CARRIED
OVER FROM PREVIOUS FCSTR...WILL NEED TO WATCH FOR SOME DEVELOPMENT
OF CONVECTION MAKING IT INTO NWRN CWA TONIGHT.
TOMORROW...HEIGHT FALLS MOVE INTO WRN HIGH PLAINS WITH SFC LOW
ORGANIZING OVER SODAK. A SWRLY MID LVL FLOW WILL BEGIN OVER THE
CWA AS THE RIDGE AXIS SHIFTS EAST. SFC HIGH PRESSURE WILL INCREASE
OVER LAKE SUPERIOR WITH DISTINCT ONSHORE COMPONENT TO BDRY LYR
WIND. TOUGH FCST FOR PRECIP AS MAIN FOCUS APPEARS TO BE SHAPING UP
OVER THE WRN CWA BY LATE IN THE DAY. CLOUDS/PRECIP FCST FOR NORTH
SHORE BASED ON A COMBINATION OF TERRAIN LIFT AND A GRADUAL
DEEPENING OF SYNOPTIC SCALE MOIST LAYER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
THE STRONG SURFACE LOW WILL MOVE NORTH ALONG THE WESTERN MINNESOTA
BORDER SATURDAY NIGHT AND SUNDAY MORNING...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY THE THE WESTERN PORTIONS OF THE
FORECAST AREA OVERNIGHT. HAVE GONE AHEAD AN INCREASED POPS TO
CATEGORICAL THERE...WITH HIGH END CHANCE TO LIKELY POPS ELSEWHERE AS
THE WARM FRONT MOVES NORTH ACROSS THE REGION. MODELS ARE GETTING
CLOSE ENOUGH TOGETHER TO HAVE A FAIRLY HIGH CONFIDENCE...THOUGH THE
TRACK IS STILL SOMEWHAT PROBLEMATIC. WITH THE SURFACE LOW MOVING
NORTHEAST OF THE REGION SUNDAY AND SUNDAY NIGHT....A COLD FRONT IS
DRAGGED THROUGH THE AREA. DEPENDING ON THE MODEL...THE TIMING
DIFFERS...BUT EITHER WAY WE ARE LOOKING AT MORE CHANCE TO LIKELY
POPS. THE ECMWF...WHICH IS FARTHER WEST THAN THE GFS IMPLIES WE MAY
HAVE SOME POTENTIAL FOR SEVERE STORMS...AS THE FRONT COMES THROUGH
LATER AND ALLOWS FOR HEATING DURING THE DAY TO BUILD INSTABILITY
AHEAD OF IT. WILL HAVE TO WATCH THIS CAREFULLY IN THE NEXT FEW
DAYS. HAVE GONE WITH SOME FAIRLY WARM HIGH TEMPS ON SUNDAY...BUT IF
THE ECMWF WORKS OUT...THESE WILL NEED TO BE RAISED. THIS STORM
LINGERS OVER WESTERN ONTARIO FOR MONDAY BEFORE MOVING OFF TO THE
NORTHEAST MONDAY AFTERNOON AND NIGHT...KEEPING SOME CHANCE POPS
GOING OVER THE AREA BOTH PERIODS WITH COOLER TEMPERATURES.
OUR NEXT SIGNIFICANT STORM SYSTEM COMES BY ON TUESDAY THROUGH
WEDNESDAY. MODELS ARE VARYING SIGNIFICANTLY BY THIS POINT...WITH
THE THE GFS BRINGING AN AREA OF MODERATE TO HEAVY RAIN ACROSS THE
FORECAST AREA...AND THE ECMWF KEEPING IT FARTHER SOUTH AND DRIER FOR
US. FOR NOW HAVE GONE WITH A BLEND APPROACH WITH SOME CHANCE POPS
AND WE WILL HAVE TO REVISIT WITH LATER FORECASTS. A STRONG SURFACE
RIDGE BUILDS INTO THE AREA FOR WEDNESDAY NIGHT AND
THURSDAY....BRINGING COOLER TEMPERATURES AND HOPEFULLY A BIT MORE
SUNSHINE TO THE REGION. LOWS BY WEDNESDAY NIGHT AND THURSDAY NIGHT
MAY DIP INTO THE 40S AGAIN FOR PORTIONS OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 650 AM CDT FRI AUG 22 2014
WIDE RANGE OF CONDITIONS ACROSS THE TERMINALS THIS MORNING...WITH
LIFR FOR KDLH...KHYR AND KBRD WHERE NORTHEAST FLOW OFF LAKE
SUPERIOR HAS GENERATED STRATUS AND EVEN SOME LIFR VISIBILITIES IN
FOG. KHIB IS IFR WITH KINL AT VFR CIGS...THOUGH VFR VISIBILITIES
BOTH LOCATIONS. CIGS AND VISIBILITIES EXPECTED TO GRADUALLY
IMPROVE THROUGH 20Z TODAY...WITH MOST TERMINALS RETURNING TO AT
LEAST MVFR CIGS AND VFR VISIBILITIES. THIS EVENING CIGS AND
VISIBILITIES TO DETERIORATE AGAIN AFTER 02Z...LIKELY DROPPING TO
IFR/LIFR CIGS AND VISIBILITIES FOR SEVERAL HOURS OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 71 60 70 61 / 20 10 20 60
INL 76 56 76 58 / 30 10 30 70
BRD 79 61 75 64 / 10 10 50 70
HYR 80 61 78 64 / 20 10 40 60
ASX 71 59 73 62 / 20 10 20 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MNZ037.
WI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR WIZ001.
LS...NONE.
&&
$$
UPDATE...LE
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
337 AM CDT FRI AUG 22 2014
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI AUG 22 2014
MID LVL RIDGING CONTINUES OVER THE CWA EARLY THIS MORNING AS A
BROAD AREA OF WEAK LOW PRESSURE SHIFTS SLOW EAST UNDERNEATH.
LATEST RUC SHOWS A 925 LOW OVER WCTRL WISC WITH AN INVERTED SHEAR
AXIS EXTENDING NORTHWEST TOWARDS KBJI AND KROX. THIS IS FOLLOWED
BY A COLD FRONT STRETCHING FROM ERN MANITOBA SOUTH TO CENTRAL
SODAK. MAIN STORY OVER CWA THIS MORNING IS TRAPPED MOIST LAYER...
ABOUT 5K FT IN DEPTH...UNDERNEATH SUBSIDENCE INVERSION. BR/FG AND
EVEN SOME DRIZZLE IS OCCURRING IN MANY AREAS. A FEW CONVECTIVE
CELLS HAVE TRIED TO DEVELOP OVER SERN WISC ZONES IN AN AREA OF LOW
LVL THETAE RIDGE AXIS. LIMITED INSTABILITY HAS ALLOWED FAIRLY
SHORT TEMPORAL NATURE TO DEVELOPMENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
TODAY...FCST MDL SNDGS SUGGEST IT MAY TAKE QUITE SOME TIME TO
DISSIPATE THE CANOPY OF STRATUS AND BR ACROSS THE REGION. COND
PRES DEFICITS SHOW A TREND TO DIMINISHING BR BY 14/15Z....THEN A
RELATIVELY SATURATED CLOUD LAYER FINALLY BREAKING AFTER 2PM.
PRECIP CHC SEEMS QUITE LIMITED BY RIDGING ALOFT AND LACK OF LOW
LVL FOCUS FOR CONVERGENCE. THE GREATEST OPPORTUNITY MAY ARISE IN
THE AFTERNOON AHEAD OF APPROACHING FRONTAL BDRY PUSHING TOWARDS
NWRN CWA. MID LVL WARMTH WILL LIMIT MUCH DEVELOPMENT UNTIL
AFTERNOON AS 70H THERMAL COOLING COMMENCES OVER WRN CWA.
TONIGHT...MID LVL RIDGE AMPLIFIES OVERHEAD TONIGHT IN RESPONSE TO
UPSTREAM STRENGTHENING OF TROF OVER ROCKIES. FRONTAL BDRY WILL
STALL NORTH AND WEST OF CWA HOWEVER ITS ASSOCIATED PREFRONTAL
THETAE RIDGE WILL BE NEARBY. ALTHOUGH THE DRY FORECAST WAS CARRIED
OVER FROM PREVIOUS FCSTR...WILL NEED TO WATCH FOR SOME DEVELOPMENT
OF CONVECTION MAKING IT INTO NWRN CWA TONIGHT.
TOMORROW...HEIGHT FALLS MOVE INTO WRN HIGH PLAINS WITH SFC LOW
ORGANIZING OVER SODAK. A SWRLY MID LVL FLOW WILL BEGIN OVER THE
CWA AS THE RIDGE AXIS SHIFTS EAST. SFC HIGH PRESSURE WILL INCREASE
OVER LAKE SUPERIOR WITH DISTINCT ONSHORE COMPONENT TO BDRY LYR
WIND. TOUGH FCST FOR PRECIP AS MAIN FOCUS APPEARS TO BE SHAPING UP
OVER THE WRN CWA BY LATE IN THE DAY. CLOUDS/PRECIP FCST FOR NORTH
SHORE BASED ON A COMBINATION OF TERRAIN LIFT AND A GRADUAL
DEEPENING OF SYNOPTIC SCALE MOIST LAYER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014
THE STRONG SURFACE LOW WILL MOVE NORTH ALONG THE WESTERN MINNESOTA
BORDER SATURDAY NIGHT AND SUNDAY MORNING...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY THE THE WESTERN PORTIONS OF THE
FORECAST AREA OVERNIGHT. HAVE GONE AHEAD AN INCREASED POPS TO
CATEGORICAL THERE...WITH HIGH END CHANCE TO LIKELY POPS ELSEWHERE AS
THE WARM FRONT MOVES NORTH ACROSS THE REGION. MODELS ARE GETTING
CLOSE ENOUGH TOGETHER TO HAVE A FAIRLY HIGH CONFIDENCE...THOUGH THE
TRACK IS STILL SOMEWHAT PROBLEMATIC. WITH THE SURFACE LOW MOVING
NORTHEAST OF THE REGION SUNDAY AND SUNDAY NIGHT....A COLD FRONT IS
DRAGGED THROUGH THE AREA. DEPENDING ON THE MODEL...THE TIMING
DIFFERS...BUT EITHER WAY WE ARE LOOKING AT MORE CHANCE TO LIKELY
POPS. THE ECMWF...WHICH IS FARTHER WEST THAN THE GFS IMPLIES WE MAY
HAVE SOME POTENTIAL FOR SEVERE STORMS...AS THE FRONT COMES THROUGH
LATER AND ALLOWS FOR HEATING DURING THE DAY TO BUILD INSTABILITY
AHEAD OF IT. WILL HAVE TO WATCH THIS CAREFULLY IN THE NEXT FEW
DAYS. HAVE GONE WITH SOME FAIRLY WARM HIGH TEMPS ON SUNDAY...BUT IF
THE ECMWF WORKS OUT...THESE WILL NEED TO BE RAISED. THIS STORM
LINGERS OVER WESTERN ONTARIO FOR MONDAY BEFORE MOVING OFF TO THE
NORTHEAST MONDAY AFTERNOON AND NIGHT...KEEPING SOME CHANCE POPS
GOING OVER THE AREA BOTH PERIODS WITH COOLER TEMPERATURES.
OUR NEXT SIGNIFICANT STORM SYSTEM COMES BY ON TUESDAY THROUGH
WEDNESDAY. MODELS ARE VARYING SIGNIFICANTLY BY THIS POINT...WITH
THE THE GFS BRINGING AN AREA OF MODERATE TO HEAVY RAIN ACROSS THE
FORECAST AREA...AND THE ECMWF KEEPING IT FARTHER SOUTH AND DRIER FOR
US. FOR NOW HAVE GONE WITH A BLEND APPROACH WITH SOME CHANCE POPS
AND WE WILL HAVE TO REVISIT WITH LATER FORECASTS. A STRONG SURFACE
RIDGE BUILDS INTO THE AREA FOR WEDNESDAY NIGHT AND
THURSDAY....BRINGING COOLER TEMPERATURES AND HOPEFULLY A BIT MORE
SUNSHINE TO THE REGION. LOWS BY WEDNESDAY NIGHT AND THURSDAY NIGHT
MAY DIP INTO THE 40S AGAIN FOR PORTIONS OF THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1240 AM CDT FRI AUG 22 2014
MAINLY IFR/MVFR CONDITIONS COVERED THE NORTHLAND AS OF LATE EVENING.
CONDITIONS ARE EXPECTED TO LOWER TO IFR/LIFR OVERNIGHT IN
FOG/STRATUS. VSBYS WILL IMPROVE FRIDAY MORNING...AND CEILINGS WILL
GRADUALLY LIFT AS WELL. SOME AREAS WILL SEE VFR CONDITIONS BY MID TO
LATE AFTERNOON.
A WARM FRONTAL BOUNDARY SOUTH OF THE NORTHLAND WAS PARTIALLY
RESPONSIBLE FOR SCATTERED SHOWERS AND A FEW THUNDERSTORMS AS WELL.
THE COVERAGE OF THE SHOWERS/STORMS ARE EXPECTED TO WANE OVERNIGHT
WITH A FEW POSSIBLE ON FRIDAY. UPPER LEVEL HEIGHTS WILL BUILD FRIDAY
AND THAT SHOULD HELP LIMIT THE COVERAGE OF SHOWERS/STORMS FRIDAY
INTO FRIDAY EVENING. MORE FOG/STRATUS WILL DEVELOP FRIDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 71 60 70 61 / 20 10 20 60
INL 76 56 76 58 / 30 10 30 70
BRD 79 61 75 64 / 10 10 50 70
HYR 80 61 78 64 / 20 10 40 60
ASX 71 59 73 62 / 20 10 20 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 AM CDT EARLY THIS MORNING FOR
LSZ142>146.
&&
$$
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1235 PM CDT Fri Aug 22 2014
.SHORT TERM: (Through Sunday)
Issued at 312 AM CDT Fri Aug 22 2014
Well it finally feels like summer. Heat index values yesterday
afternoon topped out around 105 degrees in the immediate St. Louis
Metropolitan Area where the EXCESSIVE HEAT WARNING remains in
effect until Sunday evening. Elsewhere, heat indices remained
within the 100 to 104 degree range, including locations across
northeast Missouri and west central Illinois. Will be adding the
northeast Missouri and west central Illinois counties to the HEAT
ADVISORY to account for heat index values reaching longevity
criteria of 100 degree heat index for four or more days. I expect
that the longevity of the heat wave (now likely extending into
next week) will lead to future extensions in time as confidence
increases.
Have introduced some low chance POPs for thunderstorms this
afternoon and evening across the northern half of the CWA. Hard to
ignore mesoscale model guidance suggesting a secondary warm front
developing across the northern CWA by this evening as low pressure
deepens across the Central Plains. Both 00Z 4KM NCEP and NSSL WRF
runs depict an active late afternoon and evening across the northern
CWA - with the potential for an outflow to move south toward I-70.
Again, for now, I have only increased POPs so that there is a
mention in the forecast. Day shift will have to reevaluate as HRRR
and RAP comes into range later this morning.
CVKING
.LONG TERM: (Monday through Thursday)
Issued at 312 AM CDT Fri Aug 22 2014
Hot and dry conditions extend into next week ahead of a cold front
that is now forecast to arrive on Wednesday. This front should
bring a chance of rain and utlimately cooler temperatures by
Thursday.
CVKING
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1223 PM CDT Fri Aug 22 2014
Main forecast issue is the probability for any showers and thunderstorms
and the need for inclusion in any of the TAFS. An old thunderstorm
boundary has sunk to around I-70 and this has caused some havoc in
the wind direction although they are light. Indications the
boundary will retreat northward and could result in scattered
showers and thunderstorms this afternoon across northern Missouri
into central IL which might impact KUIN. Confidence is below
average and thus have just mentioned a VCTS for this afternoon. A
higher probability of showers and thunderstorms will exist at KUIN
during the overnight hours. Elsewhere can`t rule out isolated
shower or thunderstorms with afternoon heating but the coverage and
probability are too low to mention. Largely outside of any thunderstorms,
VFR conditions will dominate with surface winds at or below 8 kts
through the period.
Specifics for KSTL:
VFR conditions are expected to dominate much of the forecast period
with surface winds at or below 8 kts. Will have to keep an eye out
for any isolated showers or thunderstorms this afternoon, and then
overnight tonight will need to monitor any showers and thunderstorms
across northern MO sagging southeastward. Confidence and probabilities
at this time are too low to mention in the TAF.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY until 7 PM CDT Sunday FOR Audrain MO-Boone MO-
Callaway MO-Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
Knox MO-Lewis MO-Lincoln MO-Madison MO-Marion MO-Moniteau
MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Shelby
MO-St. Charles MO-St. Francois MO-Ste. Genevieve MO-Warren
MO.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR St. Louis City
MO-St. Louis MO.
IL...HEAT ADVISORY until 7 PM CDT Sunday FOR Adams IL-Bond IL-Brown
IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Marion IL-Monroe IL-Montgomery IL-Pike IL-
Randolph IL-Washington IL.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR Madison IL-St.
Clair IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
626 AM CDT Fri Aug 22 2014
.SHORT TERM: (Through Sunday)
Issued at 312 AM CDT Fri Aug 22 2014
Well it finally feels like summer. Heat index values yesterday
afternoon topped out around 105 degrees in the immediate St. Louis
Metropolitan Area where the EXCESSIVE HEAT WARNING remains in
effect until Sunday evening. Elsewhere, heat indices remained
within the 100 to 104 degree range, including locations across
northeast Missouri and west central Illinois. Will be adding the
northeast Missouri and west central Illinois counties to the HEAT
ADVISORY to account for heat index values reaching longevity
criteria of 100 degree heat index for four or more days. I expect
that the longevity of the heat wave (now likely extending into
next week) will lead to future extensions in time as confidence
increases.
Have introduced some low chance POPs for thunderstorms this
afternoon and evening across the northern half of the CWA. Hard to
ignore mesoscale model guidance suggesting a secondary warm front
developing across the northern CWA by this evening as low pressure
deepens across the Central Plains. Both 00Z 4KM NCEP and NSSL WRF
runs depict an active late afternoon and evening across the northern
CWA - with the potential for an outflow to move south toward I-70.
Again, for now, I have only increased POPs so that there is a
mention in the forecast. Day shift will have to reevaluate as HRRR
and RAP comes into range later this morning.
CVKING
.LONG TERM: (Monday through Thursday)
Issued at 312 AM CDT Fri Aug 22 2014
Hot and dry conditions extend into next week ahead of a cold front
that is now forecast to arrive on Wednesday. This front should
bring a chance of rain and utlimately cooler temperatures by
Thursday.
CVKING
&&
.AVIATION: (For the 12z TAFs through 12z Saturday Morning)
Issued at 626 AM CDT Fri Aug 22 2014
Complex of storms moving east across northern Missouri as of 11z.
For now have added vcts mention at KUIN through 15z. Otherwise,
rest of taf sites to remain dry with vfr conditions and light
winds picking up from the southwest this morning. Then winds to
become light and variable once again this evening. KUIN continues
to be on southern perifery of storm activity, so added vcts
mention after 01z Saturday.
Specifics for KSTL:
Metro area to remain dry with vfr conditions and light winds
picking up from the southwest this morning. Then winds to become
light and variable once again by 01z Saturday.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY until 7 PM CDT Sunday FOR Audrain MO-Boone MO-
Callaway MO-Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
Knox MO-Lewis MO-Lincoln MO-Madison MO-Marion MO-Moniteau
MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Shelby
MO-St. Charles MO-St. Francois MO-Ste. Genevieve MO-Warren
MO.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR St. Louis City
MO-St. Louis MO.
IL...HEAT ADVISORY until 7 PM CDT Sunday FOR Adams IL-Bond IL-Brown
IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Marion IL-Monroe IL-Montgomery IL-Pike IL-
Randolph IL-Washington IL.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR Madison IL-St.
Clair IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
314 AM CDT Fri Aug 22 2014
.SHORT TERM: (Through Sunday)
Issued at 312 AM CDT Fri Aug 22 2014
Well it finally feels like summer. Heat index values yesterday
afternoon topped out around 105 degrees in the immediate St. Louis
Metropolitan Area where the EXCESSIVE HEAT WARNING remains in
effect until Sunday evening. Elsewhere, heat indices remained
within the 100 to 104 degree range, including locations across
northeast Missouri and west central Illinois. Will be adding the
northeast Missouri and west central Illinois counties to the HEAT
ADVISORY to account for heat index values reaching longevity
criteria of 100 degree heat index for four or more days. I expect
that the longevity of the heat wave (now likely extending into
next week) will lead to future extensions in time as confidence
increases.
Have introduced some low chance POPs for thunderstorms this
afternoon and evening across the northern half of the CWA. Hard to
ignore mesoscale model guidance suggesting a secondary warm front
developing across the northern CWA by this evening as low pressure
deepens across the Central Plains. Both 00Z 4KM NCEP and NSSL WRF
runs depict an active late afternoon and evening across the northern
CWA - with the potential for an outflow to move south toward I-70.
Again, for now, I have only increased POPs so that there is a
mention in the forecast. Day shift will have to reevaluate as HRRR
and RAP comes into range later this morning.
CVKING
.LONG TERM: (Monday through Thursday)
Issued at 312 AM CDT Fri Aug 22 2014
Hot and dry conditions extend into next week ahead of a cold front
that is now forecast to arrive on Wednesday. This front should
bring a chance of rain and utlimately cooler temperatures by
Thursday.
CVKING
&&
.AVIATION: (For the 06z TAFs through 06z Friday Night)
Issued at 1125 PM CDT Thu Aug 21 2014
VFR conditions are expected to continue over the next 24 hours
outside of any convection. Some activity has developed over far
south-central Iowa over and will have to be watched as some of
these storms may approach KUIN. Left KUIN dry though for now as
mid/upper level winds suggest aforementioned storms should move
east and stay north of site. Otherwise...hot/humid weather to
continue with winds by day out of the southwest and at night
backing to a more southeasterly direction. Did add a VCTS group at
KUIN for Friday evening as a warm front will move northeast with
some convection firing near this boundary per latest model guidance.
Specifics for KSTL:
VFR conditions are expected to continue over the next 30 hours
outside of any convection. Hot/humid weather to
continue with winds by day out of the southwest and at night
backing to a more southeasterly direction. Could be some widely
scattered storms Friday afternoon as a boundary lifts to the north
and east...but left out of TAF for now as probability of
occurrence of a storm affecting the terminal is quite low.
Gosselin
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 98 80 99 80 / 10 20 5 5
Quincy 94 75 95 75 / 20 30 5 5
Columbia 97 75 98 74 / 10 10 5 5
Jefferson City 98 76 99 74 / 10 10 5 5
Salem 93 75 95 75 / 10 20 5 5
Farmington 96 77 97 75 / 10 10 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY until 7 PM CDT Sunday FOR Audrain MO-Boone MO-
Callaway MO-Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
Knox MO-Lewis MO-Lincoln MO-Madison MO-Marion MO-Moniteau
MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Shelby
MO-St. Charles MO-St. Francois MO-Ste. Genevieve MO-Warren
MO.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR St. Louis City
MO-St. Louis MO.
IL...HEAT ADVISORY until 7 PM CDT Sunday FOR Adams IL-Bond IL-Brown
IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Marion IL-Monroe IL-Montgomery IL-Pike IL-
Randolph IL-Washington IL.
EXCESSIVE HEAT WARNING until 7 PM CDT Sunday FOR Madison IL-St.
Clair IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
926 PM MDT SAT AUG 23 2014
.UPDATE...
WIDESPREAD PCPN OCCURRING ACROSS OUR WEST AND CENTRAL PARTS AS
LOW SHIFTS EAST ALLOWING ISENTROPIC ASCENT FROM THE NORTH TO TAKE
OVER. EAST OF UPPER LOW...PV MAX LIFTING OUT OF NORTHEAST WY WILL
PROVIDE A PERIOD OF SHOWERS AND ISOLD TSTMS TO OUR EASTERN PARTS
FOR THE REMAINDER OF THE EVENING. LATEST RAP TRENDS SUGGEST
STRONGER ASCENT INTO SUNDAY MORNING AS LOW MOVES SLOWLY TO THE
EAST/NORTHEAST. HAVE UPDATED POPS AGAIN TO SHOW HIGHER
PROBABILITIES LATE TONIGHT AND SUNDAY MORNING...WITH A GRADUAL
EASTWARD AND NORTHWARD TREND OVER THIS TIME. RAP/NAM ALSO SUGGEST
700MB TEMPS TO -2C ACROSS OUR WEST LATER TONIGHT AND THIS IS
CONSISTENT WITH 00Z TFX RAOB. THIS WILL ALLOW FOR SNOW LEVELS DOWN
TO AROUND 7.5KFT OVER THE CRAZY...BEARTOOTH AND ABSAROKA MTNS.
TEMP AT WICKED CREEK RAWS DOWN TO 36F AT 9PM...AT AN ELEVATION OF
7.6KFT.
REGARDING FLOOD HIGHLIGHTS...WILL MAKE NO CHANGES TO FLOOD WARNING
FOR WHEATLAND...GOLDEN VALLEY AND MUSSELSHELL COUNTIES THOUGH
LATEST HYDROGRAPHS STARTING TO SHOW A DECREASING TREND ON THE
UPPER MUSSELSHELL. WILL ALSO MAKE NO CHANGE TO SMALL STREAM FLOOD
ADVISORY FOR FALLON AND NORTHERN CARTER COUNTIES...DUE TO HEAVY
PCPN IN THIS AREA LAST NIGHT. FOR THE REMAINING AREAS HAVE OPTED
TO CANCEL THE FLOOD WATCH AS TROWAL PCPN WILL BE STEADY BUT NOT AS
HEAVY AS THE MORE CONVECTIVE SHOWERS EARLIER IN THE EVENT. RECENT
CALLS AROUND THE AREA INDICATES NO FLOOD PROBLEMS TO THIS POINT...
THOUGH OBVIOUSLY THERE WILL BE PLENTY OF PONDED WATER AND SMALL
STREAM RISES SO CAUTION NEEDS TO BE USED IF TRAVELING ON RURAL
ROADS. JKL
PREVIOUS DISCUSSION ISSUED 649PM...
UPPER LOW CONTINUES TO MOVE SLOWLY EAST WHILE PRODUCING
WIDESPREAD PCPN WITH THE EXCEPTION OF PARTS OF OUR SOUTHEAST WHERE
SOME MID LEVEL DRY SLOTTING EXISTS. PUSH OF NORTHERLY ISENTROPIC
ASCENT ALONG WITH VEERED LOW-MID LEVEL WINDS HAS ALLOWED FOR PCPN
TO PICK UP IN OUR WEST TO CENTRAL PARTS INCLUDING BILLINGS. LATEST
RAP SHOWS THIS CONTINUING FOR SEVERAL HOURS BEFORE ASCENT SHIFTS
N-NE...SO HAVE MAXED OUT POPS IN THIS AREA THIS EVENING. OTHER
THAN THE POP ADJUSTMENTS THE FORECAST REMAINS ON TRACK. BIGGEST
IMPACT IS THE HEAVY PCPN AND ITS IMPACT ON RIVERS AND STREAMS SO
WILL CONTINUE TO MONITOR THESE. GIVEN WE ARE GETTING ON THE TROWAL
SIDE OF THIS SYSTEM WE ARE PAST THE HEAVIEST RAINFALL RATES NOW.
JKL
&&
.SHORT TERM...VALID FOR SUN AND MON...
NEGATIVE TILT TROUGH TRACKING RIGHT ACROSS OUR REGION TONIGHT.
STRONG ISENTROPIC LIFT UNDER DIFFLUENT FLOW ALOFT AHEAD OF LOW
PRESSURE SYSTEM HAS PRODUCED CONSIDERABLE RAINFALL OVER THE
REGION. WE HAVE HAD 1-3 INCHES COMMON OVER MUCH OF THE FORECAST
AREA...ALONG WITH REPORTS OF OVER 4 INCHES IN MUSSELSHELL...NEAR
BIG TIMBER AND OUT SOUTH OF BAKER. DUE TO THE POTENTIAL OF AN
ADDITIONAL 1 OR 2 INCHES WE HAVE UPGRADED WATCHES TO WARNINGS
ACROSS OUR NW ZONES...AND A SMALL STREAM FLOOD ADVISORY IN THE
BAKER VICINITY.
MODELS BEGIN TO SWING THE FLOW AROUND THE LOW PRESSURE SYSTEM
TO THE N/NW IN OUR WESTERN ZONES LATER THIS EVENING AS SYSTEM
LIFTS E/NE ACROSS SOUTHERN MONTANA. THIS SETS UP A TROWAL FEATURE
HEADING INTO SUNDAY WITH PRECIP WRAPPING AROUND INTO OUR NORTHERN
AND CENTRAL ZONES FROM THE NORTH...INCLUDING NORTHERN
ROSEBUD/TREASURE/NORTHERN CUSTER AND MAYBE NE YELLOWSTONE
COUNTIES. THIS AREA WILL SEE THE HIGHEST POPS AND QPF FOR THE
REST OF THIS EVENT. THE PRECIP FINALLY DIMINISHES BY SUNDAY
EVENING AS THE UPPER LOW RACES ACROSS EASTERN NORTH DAKOTA.
WE GET A BREAK IN THE WEATHER MONDAY BEHIND THE EXITING UPPER
LOW...BUT THE SOUTHERN BRANCH OF SPLIT JET DROPS ENERGY INTO THE
DESERT SW WHICH WILL BRING A TROUGH AXIS THROUGH SOUTHERN MONTANA
BY MONDAY EVENING. I PULLED BACK THE POPS A BIT WEST FOR THIS AS
FORCING IS WEAK AND LIMITED TO MAINLY SW MONTANA AND OUR
BEARTOOTH/ABSAROKA RANGES. BT
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MODELS CONTINUE TO BE IN GOOD AGREEMENT...PROMPTING A FEW CHANGES
TO THE EXTENDED FORECAST PERIOD. CHANGES CENTERED AROUND GENERALLY
COOLING TEMPS SLIGHTLY THROUGHOUT THE PERIOD...RESULTING IN A
SLIGHTLY MORE GRADUAL WARM UP. OTHER CHANGES WERE TO ADD SOME
SLIGHT POPS ACROSS THE REGION FOR THE LATTER PORTION OF THE
PERIOD.
A SECOND UPPER LOW EMBEDDED WITHIN THE BROAD TROF CONTINUES
PASSAGE THROUGH THE REGION TUESDAY. THIS KEEPS SHOWER AND
THUNDERSTORM POTENTIAL INTACT ACROSS THE ENTIRE FORECAST AREA
THROUGH TUESDAY. THEREFORE TEMPS WILL REMAIN WELL BELOW NORMAL
TUESDAY...WITH READINGS ONLY IN THE 60S TO LOWER 70S. THE UPPER
LEVEL LOW IS PROGGED TO SHIFT EAST WITH RIDGING BUILDING IN ON
WEDNESDAY...WITH RIDGING CONTINUING INTO FRIDAY. A WARMING TREND
WILL BEGIN AT THIS POINT...WITH HIGHS STILL BELOW SEASONAL AVERAGE
AT MID 70S TO AROUND 80 WEDNESDAY. HAVE ADDED SOME SLIGHT EVENING
POPS IN THE EAST WEDNESDAY...AS A WEAK WAVE PUSHES THROUGH THE
AREA TO INTERACT WITH PEAK DIURNAL HEATING...AND SIGNIFICANT SFC
WATER. DRYING CONDITIONS ARE EXPECTED...BUT THE AMOUNT OF
MOISTURE AVAILABLE ON THE GROUND CAUSES SOME CONCERN. HAVE OPTED
TO KEEP THURSDAY DRY WITH RIDGING IN CONTROL OVER THE REGION...BUT
WEAK WAVES CONTINUE THROUGH THE FLOW...AND RIDGE IS NOT VERY
STRONG. BRING SLIGHT MOUNTAIN POPS BACK THURSDAY NIGHT THROUGH
FRIDAY...AS RIDGE FLATTENS. ZONAL FLOW TAKES OVER LATE
FRIDAY...AND THERE WILL AGAIN BE SOME POTENTIAL FOR ISOLATED
SHOWERS AND THUNDERSTORMS THROUGH THE REMAINDER OF THE
PERIOD. TEMPS RETURN TO ABOUT SEASONAL AVERAGE ON THURSDAY...AND
CLIMBING SLIGHTLY ABOVE NORMAL FOR FRIDAY AND SATURDAY. DID PAIR
TEMPS BACK SLIGHTLY THROUGHOUT THE PERIOD...BUT STILL A GRADUAL
WARMUP. AAG
&&
.AVIATION...
WIDESPREAD RAINFALL...HEAVY AT TIME...IS EXPECTED TO CONTINUE
ACROSS THE REGION THROUGH THE NIGHT. ISOLATED THUNDERSTORMS ARE
OCCURRING IN SOUTHEASTERN MONTANA AS WELL. MVFR TO IFR CIGS WILL
CONTINUE TO BE COMMON...WITH LIFR TO VLIFR CONDITIONS IN HEAVIER
PRECIP...LOWERING CIGS AND FOG. GUSTY WINDS HAVE DEVELOPED THIS
AFTERNOON...WITH GUSTS TO 30KTS. WINDS ARE FROM THE WEST AND NORTHWEST
IN THE WESTERN ZONES...AND FROM THE EAST AND NORTHEAST IN THE EASTERN
ZONES. AREA MOUNTAINS WILL BE OBSCURED THROUGHOUT THE DAY. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 047/062 047/066 050/071 050/080 057/085 061/087 061/085
+6/W 11/E 22/T 11/U 01/U 11/U 22/T
LVM 046/063 042/066 045/071 045/081 051/084 051/086 053/085
74/W 23/T 32/T 11/U 10/U 12/T 22/T
HDN 049/063 045/070 050/073 048/081 055/086 059/090 059/087
+8/W 11/E 22/T 11/U 01/U 11/U 12/T
MLS 051/059 047/068 051/070 050/080 057/085 062/092 062/091
+9/W 31/E 22/T 11/U 11/U 12/T 22/T
4BQ 050/061 046/068 052/069 048/079 056/085 060/091 062/091
64/W 21/B 43/T 22/T 21/U 12/T 22/T
BHK 050/059 045/064 046/067 045/076 053/081 059/088 058/087
66/W 31/E 34/T 22/T 21/U 12/T 22/T
SHR 046/063 044/068 048/070 045/079 051/085 055/091 056/088
93/W 11/B 34/T 21/U 00/U 11/U 12/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
702 PM CDT SAT AUG 23 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
STUBBORN LOWER CLOUDS STILL HANGING ON ACROSS NORTHWEST PART OF
THE FORECAST AREA. SULTRY AIRMASS TODAY AS WELL...WITH DEWPOINTS
AROUND 70 SEVERAL LOCATIONS. MOST MODELS TRY TO PUMP IN SOME DRIER
AIR FROM THE SOUTH THROUGH THIS EVENING...WITH THE HRRR MOST
AGGRESSIVE. THAT COULD PROVIDE A LITTLE HUMIDITY RELIEF TO SOME
SPOTS IN THE SOUTHERN/SOUTHEAST FORECAST AREA. AS WE WORK INTO
TONIGHT...THE PROSPECT OF THUNDERSTORMS IS MUCH MUCH LOWER...BUT
NOT NIL. A DECENT LOW LEVEL JET WILL DEVELOP AND THAT COULD SUSTAIN
HIGH PLAINS CONVECTION...BUT ALSO SPARK A FEW OTHER ISOLATED SHOWERS
AND STORMS. OVERALL COVERAGE SHOULD BE ISOLATED...BUT CAN NOT
TOTALLY RULE IT OUT.
SUNDAY SHOULD START WITH LINGERING MID/HIGH CLOUDS FROM LEFTOVER
SHOWERS AND THUNDERSTORMS IN PARTS OF THE PLAINS. THESE MAY HOLD
OVER INTO THE POST SUNRISE HOURS OVER NORTHERN PARTS OF THE
FORECAST NEAR A FRONTAL BOUNDARY...BUT COVERAGE WILL BE SPARSE
AND 20 PERCENT CHANCES REPRESENT RAIN RISK WELL.
A WEAK FRONTAL BOUNDARY WILL ATTEMPT TO MOVE ACROSS THE FORECAST
AREA SUNDAY. MODELS SEEM A BIT AGGRESSIVE...BUT SOMETIMES THAT DOES
WORK OUT. EXPECT A SHIFTING WIND...AND THEN A DYING WIND AS THE
FORECAST IS LEFT TO FLOUNDER IN THE SURFACE SURFACE WITH THE FRONT
WEAKENING WITH TIME. THE WEAK NATURE OF THE FRONT AND SOME WARM MID
LEVEL TEMPERATURES WILL PROBABLY KEEP ANY DEVELOPMENT OF
THUNDERSTORMS NEAR OR ALONG THE FRONT VERY SPARSE AND TOWARD EVENING
AT THE EARLIEST. HAVE KEPT SIMILAR IDEA OF LOWER DEWPOINTS BEHIND
THE FRONTAL PASSAGE...BUT HAVE SOME DOUBT PLACES LIKE GRAND ISLAND
AND HASTINGS COULD DROP TO A SUB-60 DEWPOINT LATE SUNDAY AFTERNOON.
THAT WOULD BE NICE BUT WE WILL SEE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH MUCH OF THE
EXTENDED PERIODS AS THE LOCAL AREA WILL REMAIN UNDER THE INFLUENCE
OF A LARGE TROUGH OF LOW PRESSURE ACROSS THE INTERMOUNTAIN WEST
WITH WEST TO SOUTHWESTERLY FLOW PERSISTING ALOFT.
EXPECT THE MAIN UPPER LEVEL LOW ACROSS THE DAKOTAS SUNDAY EVENING
TO LIFT NORTHEAST...WITH A SECONDARY FRONTAL BOUNDARY PUSHING
ACROSS THE LOCAL AREA. WHILE THIS FRONTAL BOUNDARY MAY PROVIDE THE
TRIGGER FOR SOME ELEVATED CONVECTION ACROSS THE SOUTHEASTERN
PORTIONS OF THE LOCAL AREA EARLY IN THE EVENING...EXPECT THE
BETTER CHANCES TO SPREAD FROM WEST TO EAST AFTER MIDNIGHT AS A
TRAILING MID LEVEL DISTURBANCE MOVES ACROSS THE LOCAL AREA FROM
THE HIGH PLAINS AND A WEAK LOW LEVEL JET FOCUSES ITSELF ACROSS
NORTH CENTRAL KANSAS.
AS THIS FIRST UPPER LEVEL LOW TRACKS WELL INTO CANADA...EXPECT A
SECOND UPPER LEVEL LOW TO SLIDE FROM THE PACIFIC NORTHWEST AND
INTO THE INTERMOUNTAIN WEST BY MONDAY...MAINTAINING SOUTHWESTERLY
ALOFT ACROSS THE REGION. WHILE CHANCES FOR PRECIPITATION WILL
DECREASE SOME DURING THE DAY ON MONDAY...KEPT SOME SMALL POPS IN
THE FORECAST AS THE OLD FRONTAL BOUNDARY WILL BE MEANDERING
ACROSS THE REGION. THAT SAID...THE BETTER SHOT FOR MORE
WIDESPREAD CONVECTION WILL BE MONDAY NIGHT...AS YET ANOTHER UPPER
LEVEL DISTURBANCE IN SOUTHWESTERLY FLOW TRAVERSES THE REGION IN
CONCERT WITH AN INCREASING LOW LEVEL JET AIMED ACROSS SOUTH
CENTRAL NEBRASKA. WITH SEVERAL THOUSAND JOULES OF CAPE IN PLACE
AND MODEST SHEAR VALUES FORECAST...EXPECT THE POTENTIAL FOR AN
ACTIVE NIGHT ACROSS THE LOCAL AREA...ESPECIALLY FROM THE STATE
LINE NORTH. DUE TO SOME DISCREPANCIES IN MODEL DATA...
HOWEVER...ONLY WENT AHEAD AND ADVERTISED LIMITED SEVERE POTENTIAL
FOR MONDAY NIGHT IN THE HWO.
OTHERWISE...THUNDERSTORM ACTIVITY TUESDAY SHOULD ONCE AGAIN BE
FOCUSED NEAR THE LOW LEVEL JET DURING THE EVENING AND OVERNIGHT
HOURS...WITH A COLD FRONT EXPECTED TO BRING YET ANOTHER CHANCE
FOR THUNDERSTORMS ACROSS THE LOCAL AREA WEDNESDAY AND WEDNESDAY
NIGHT. WHILE A CHANCE FOR PRECIPITATION IS IN THE FORECAST SUNDAY
THROUGH THURSDAY...AT THIS TIME THE BEST POTENTIAL FOR ANY SEVERE
WEATHER APPEARS TO BE PRIMARILY DURING THE EVENING AND OVERNIGHT
HOURS MONDAY THROUGH WEDNESDAY...WITH A COOLER...DRIER...AND MORE
STABLE AIRMASS EXPECTED TO SETTLE IN ACROSS THE REGION TO END THE
WEEK.
HYDROLOGY WISE...DUE TO THE RECENT RAINFALL AND SATURATED SOILS
ACROSS MUCH OF THE LOCAL AREA...CONTINUED WITH THE MENTION OF
LOCALIZED FLOODING THE HWO IN THIS UNSETTLED PATTERN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 700 PM CDT SAT AUG 23 2014
LOW-LEVEL WIND SHEAR WILL BE THE BIGGEST CONCERN AS A LOW-LEVEL
JET KICKS UP JUST AHEAD OF A COLD FRONT. ONCE THE COLD FRONT
PASSES THROUGH...WIND SHEAR SHOULD NO LONGER BE AN ISSUE. THERE
COULD BE SOME ISOLATED TO SCATTERED THUNDERSTORMS NEAR THE FRONT
AS IT PASSES. SEVERE WEATHER IS NOT EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MORITZ
LONG TERM...ROSSI
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
259 PM CDT FRI AUG 22 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM CDT FRI AUG 22 2014
THE HIGHLIGHT OF THE SHORT TERM PERIOD WILL BE THE FACT WE ARE
EXPECTING THUNDERSTORMS TODAY/TONIGHT. THERE STILL REMAINS SOME
UNCERTAINTY FOR TIMING...LOCATION...AND OVERALL DEVELOPMENT. THE
WARM FRONT TO OUR SOUTH...WHICH IS SITUATED OVER THE KANSAS/NEBRASKA
BORDER...IS JUST MOSEYING ALONG TODAY AND HAS CAUSED SOME CONCERN
FOR DEVELOPMENT. SHOWERS/STORMS SHOULD DEVELOP ALONG THIS BOUNDARY AS
THE CAP BEGINS TO BREAK. SPC MESOSCALE ANALYSIS PAGE HAS US CAPPED
UNTIL ABOUT 22-23Z. AT THIS TIME WE SHOULD SEE THE BEGINNING STAGES
FOR INITIATION ALONG THE BOUNDARY TO OUR SOUTH. AMPLE INSTABILITY OF
ABOUT 2000-3000 J/KG WILL BE IN PLACE...DUE TO A VERY MOIST BOUNDARY
LAYER AND STEEP LAPSE RATES. MOST UNSTABLE CAPE COULD BE AS HIGH AS
4000 J/KG. BULK SHEAR 0-6 KM WILL BE AROUND 30 KNOTS...AND THIS IS
NOT TOO IMPRESSIVE...HOWEVER...LOW LEVEL SHEAR WILL BE STRONG.
EARLIER RUNS OF THE RAP INDICATED HELICITY VALUES NEAR 400 M2/S2
WOULD BE IN PLACE AROUND 23Z FOR WESTERN PORTIONS OF THE CWA. THESE
VALUES WILL PUSH EASTWARD THROUGH THE AFTERNOON/EVENING. THESE LOW
LEVEL HELICITY VALUES COUPLED WITH AMPLE INSTABILITY WILL POSE A
THREAT FOR SOME ISOLATED TORNADOES...MAINLY FOR OUR NEBRASKA
COUNTIES. WITH THAT BEING...WIND AND HAIL WILL BE THE MAIN THREATS
TODAY/TONIGHT. THE BEST CHANCE FOR SEVERE WEATHER WILL BE ACROSS OUR
NEBRASKA COUNTIES...BUT THE ENTIRE CWA DOES HAVE THE POTENTIAL FOR
SEVERE WEATHER. I DO EXPECT THUNDERSTORM ACTIVITY TO KICK INTO GEAR
AROUND 6 OR 7 PM...IF NOT SOONER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM CDT FRI AUG 22 2014
VARIOUS RAIN CHANCES FOR THE WEEKEND AND IN TO THE FIRST PART OF
THE WORK WEEK...ALONG WITH FLUXUATING TEMPERATURES ARE PRIMARY
FORECAST CONCERNS. WILL KEEP THIS FAIRLY SHORT DUE TO POSSIBLE
SEVERE WEATHER DEVELOPING LATER THIS AFTERNOON.
STARTING OUT SATURDAY EVENING IN THE MID/UPPER LEVELS...THERE SHOULD
BE A LARGE AMPLITUDE TROUGH OVER THE ROCKIES WITH A CLOSED LOW
SITUATED OVER EAST CENTRAL MONTANA...AS THE CURRENT SYSTEM OVER THE
PACIFIC NW DRIFTS EASTWARD. THIS WILL PUSH THE RIDGE A LITTLE EAST
AS WELL WITH THE AXIS STRETCHING FROM LAKE SUPERIOR TO MISSISSIPPI.
THE BETTER FORCING WITH THE LOW PRESSURE SHOULD BE TO THE WEST AND
NORTH OF OUR REGION. AT THE SURFACE...EXPECT A FRONTAL BOUNDARY TO
BE TO OUR NORTH ACROSS SDAK AT 00Z AND THEN THIS WILL PUSH INTO OUR
AREA BY SUNDAY MORNING. HAS NOT TAKEN A WHOLE LOT TO SET OFF
CONVECTION THE PAST WEEK AND WHILE THE SET UP FOR SATURDAY NIGHT IS
NOT AS GOOD AS TONIGHT...WILL PROBABLY STILL NEED SOME LOW POPS
GIVEN APPROACHING WEAK COLD FRONT AND ANTICIPATED LOW LEVEL JET.
PREVIOUS SHIFT AFD NOTED SOME HEAT BURST POTENTIAL WITH ANY
THUNDERSTORMS THAT DO DEVELOP AND THIS SCENARIO STILL IN PLACE.
WEATHER SHOULD BE QUIET DURING THE DAYTIME ON SUNDAY BEHIND THE COLD
FRONT AND POSSIBLE SUNDAY NIGHT ALTHOUGH BOTH THE NAM AND GFS ARE
DEVELOPING SOME PRECIPITATION TO THE WEST AND MOVING ACROSS THE CWA
SUNDAY NIGHT. GFS APPEARS TO OVERDEVELOP A VORTICITY MAX ALTHOUGH
DIFFICULT TO TOTALLY DISCOUNT WITH CYCLONIC FLOW IN UPPER LEVELS.
MONDAY NIGHT AND TUESDAY NIGHT STILL LOOK ACTIVE AS YET ANOTHER HIGH
AMPLITUDE TROUGH IS SLATED TO MOVE ACROSS THE ROCKIES AND INTO THE
PLAINS. AT THE SURFACE AN EAST/WEST STATIONARY FRONT WILL HANG OUT
OVER THE AREA RESULTING IN THE CLASSIC NIGHTTIME RAIN EVENTS. BY
WEDNESDAY THE EXTENDED MODELS IN DECENT AGREEMENT IN PUSHING THE
TROUGH EAST THROUGH THE CWA WITH RIDING THEN MOVING IN TO QUIET
THINGS DOWN FOR THE REMAINDER OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM CDT FRI AUG 22 2014
CONDITIONS AT BOTH TERMINAL SITES ARE EXPECTED TO REMAIN IN VFR
THROUGHOUT MOST OF THE TAF PERIOD. THE ONLY CONCERN WILL BE
THUNDERSTORM ACTIVITY LATER THIS AFTERNOON/EVENING. AT THIS
TIME...CONDITIONS WILL LIKELY DETERIORATE. HOWEVER...CONFIDENCE IS
NOT EXTREMELY HIGH AT THIS POINT FOR TIMING...LOCATION...AND
OVERALL LIKELIHOOD OF DEVELOPMENT. AT THIS POINT...WE DO EXPECT
SHOWERS/STORMS TO DEVELOP ALONG THE WARM FRONT WHICH IS JUST
SOUTH OF BOTH TERMINAL SITES...NEAR THE NEBRASKA/KANSAS BORDER.
THIS FRONT WILL MOSEY NORTH THROUGHOUT THE DAY AND ONCE THE CAP
BREAKS SHOWERS SHOULD BEGIN. THE BEST CHANCE FOR THUNDERSTORM
ACTIVITY IS INDICATED IN THE TAF TO BEGIN AROUND 01Z. THE TAF WILL
BE AMENDED FOR ANY CHANGES ONCE INITIATION BECOMES CLEARER. CLOUD
COVER WILL INCREASE THROUGHOUT THE DAY AND OVERNIGHT AS WELL...BUT
CEILINGS SHOULD REMAIN VFR THROUGH THE VALID TAF PERIODS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...GUERRERO
LONG TERM...EWALD
AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1250 PM CDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 1236 PM CDT FRI AUG 22 2014
SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP IN NORTHEAST KANSAS
AND DRIFT INTO SOUTHEAST NEBRASKA THIS EARLY AFTERNOON IN WEAK MID
LEVEL WARM ADVECTION REGIME. THESE WILL CONTINUE TO MEANDER
THROUGH THE AREA BUT EXPECT COVERAGE TO GRADUALLY DIMINISH THROUGH
THE AFTERNOON AS UPPER RIDGING NOSES SLIGHTLY NORTH AND WARMS MID
LEVEL TEMPERATURES. FARTHER NORTH WHERE PLENTY OF SUNSHINE HAS
BEEN SEEN...BROKEN CU FIELD HAS DEVELOPED JUST NORTHWEST OF
INTERSTATE 80 NEAR STATIONARY FRONT DELINEATED BY LIGHT NORTHEAST
WINDS IN NORTHEAST NEBRASKA AND SOUTHEAST WINDS TO THE SOUTH.
LAST FEW RAP FORECASTS SUGGEST SOME CONVECTION COULD FIRE LATER
THIS AFTERNOON CLOSE TO THIS BOUNDARY...LIKELY FROM THE OMAHA
METRO AND WEST...IN AREA WHERE MLCAPES HAVE INCREASED TO NEAR 3500
J/KG. SHEAR IS WEAK HERE...BUT HIGH INSTABILITY COULD LEAD TO
STRONG STORMS IF THINGS DO FIRE. OTHERWISE WE ARE STILL EXPECTING
INCREASING CHANCES FOR STORMS AS THE EVENING PROGRESSES WITH
APPROACH OF STRONG SHORTWAVE ENTERING THE HIGH PLAINS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 341 AM CDT FRI AUG 22 2014
CONVECTIVE ACTIVITY HAS DEVELOPED OVER SWRN IA AND SERN NEB THIS
MORNING ALONG A SFC TROF EXTENDING FROM NRN IA TO WRN KS. SIMILAR
TO THE LAST SEVERAL NIGHTS...ENVIRONMENT IS QUITE UNSTABLE WITH
MUCAPES AROUND 3000 J/KG WITH A STRONG LLVL MOISTURE FEED INTO THE
PLAINS. EXPECT ACTIVITY WILL GRADUALLY DIMINISH OVER THE NEXT
SEVERAL HOURS AND BE OUT OF THE CWA BY SUNRISE.
MOST PRESSING ISSUE FOR THIS FCST PACKAGE IS POTENTIAL SVR
TSTMS ALONG WITH HEFTY RAINFALL ANTICIPATED LATER TONIGHT.
MODELS HAVE BEEN CONSISTENT LAST SEVERAL RUNS FOCUSING IN ON THE
NRN CWA WITH RESPECT TO HIGH POTENTIAL FOR HEAVY NOCTURNAL PCPN
LATER TONIGHT. AN OPEN GULF WITH PERSISTENT MOISTURE ADV THRU
TODAY WILL ENSURE A MOISTURE RICH ENVIRONMENT WILL BE IN PLACE
DURING THE OVERNIGHT HOURS.
TODAY...MODELS PROG A POTENT LITTLE VORT MAX EJECTING OUT OF THE
BASE OF A DEEP UPPER TROF SITUATED OVER THE WRN CONUS WITH DPVA
INDUCING LEESIDE CYCLOGENESIS INVOF THE CNTRL HIGH PLAINS. MODELS
AGREE SFC LOW WILL RAPIDLY LIFT TWD THE DAKOTAS THIS AFTN ALONG
WITH ATTENDANT WARM FRONT PUSHING INTO THE CWA LATE THIS AFTN.
COMBINATION OF STOUT INSTABILITY/EFF SHEAR AND ADEQUATE DEEP LYR
SHEAR WITH PROVIDE A FAVORABLE ENVIRONMENT FOR LATE AFTN/EARLY
EVENING SUPERCELL DEVELOPMENT. IN ADDITION...VERY HEAVY
RAINFALL...MAINLY OVER THE NRN CWA...LOOKS VERY PROBABLE TONIGHT
GIVEN COMBINATION OF WARM CLOUD DEPTH AROUND 4500 METERS/SYNOPTIC
SCALE MAX OMEGA WILL BE IN PHASE WITH PWS GREATER THAN 2". BEST
MOISTURE/FORCING THEN QUICKLY LIFTS NORTH OF THE CWA EARLY SAT
MORNING.
SAT NIGHT AND SUN...MODELS PROG A SOMEWHAT STRONG COLD FRONT
APPROACHING THE CWA. NOT ALL THAT IMPRESSED WITH PCPN POTENTIAL SO
WILL OPT FOR TOKEN 20S DURING THOSE PDS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 341 AM CDT FRI AUG 22 2014
COMPARED TO 21/00Z RUN...LATEST ECM IS NOW TRYING TO COME BACK IN
LINE WITH GFS/CMC SOLUTIONS SWEEPING A CANADIAN AIR MASS INTO THE
NRN/CNTRL PLAINS LATER NEXT WEEK WITH PCPN CHANCES FOCUSED ON
FRONTAL BNDRY PASSAGE. GOING POPS LOOK REASONABLE THUS NO MAJOR
CHANGES PLANNED.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1236 PM CDT FRI AUG 22 2014
AREA OF CUMULUS CLOUDS HAD DEVELOPED AT TAF ISSUANCE TIME AND
WILL AFFECT ALL TAF SITES THIS AFTERNOON. BROKEN CLOUDS WILL
LIKELY REMAIN VFR...BUT SOME FL020 CIGS COULD OCCUR NEAR KOFK FOR
A TIME EARLY IN THE AFTERNOON. THEN THE CHANCE FOR SCATTERED
CONVECTION WILL INCREASE LATE THIS AFTERNOON...AND ESPECIALLY
BY LATE EVENING...AS A STRONG SHORTWAVE LIFTS INTO THE PLAINS.
STORMS COULD FIRE AT ANY TIME AFTER 22Z BUT LATEST TRENDS SUGGEST
KOMA WILL BE MOST LIKELY SITE TO SEE AFTERNOON AND EARLY EVENING
ACTIVITY. OTHERWISE EXPECT CHANCES AND AREAL COVERAGE TO INCREASE
BY 05Z AT ALL SITES WITH KOFK THE MOST LIKELY TO SEE OVERNIGHT
CONVECTION. ATTENDANT MVFR/IFR CONDITIONS WILL PREVAIL IN ANY
STORMS. THUNDERSTORMS SHOULD BE MOVING NORTH OF ALL TAF SITES BY
14Z WITH VFR CONDITIONS AND SOUTHEAST WINDS NEAR 10KT PREVAILING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DERGAN
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
338 AM CDT FRI AUG 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI AUG 22 2014
FOCUS IS THUNDERSTORM AND SEVERE WEATHER POTENTIAL.
THE PATTERN ALOFT WAS DOMINATED BY A RIDGE IN THE NORTHERN
PACIFIC...A TROUGH ALONG THE WEST COAST AND RIDGING FROM THE GULF
COAST TO THE GREAT LAKES REGION. AT THE SURFACE...LOW PRESSURE WAS
ORIENTED FROM NORTHEAST NM TO SOUTHERN MN...AND THE SFC TROUGH/WARM
FRONTAL BOUNDARY WAS ACTIVE FOR CONVECTION DURING THE EVENING
HOURS.
AS WE HEAD THROUGH THE DAY TODAY...THE SURFACE LOW WILL DEEPEN AND
LIFT NORTH ACROSS WESTERN KANSAS WITH THE WARM FRONTAL BOUNDARY
ORIENTING NEAR THE KS/NEB STATELINE TOWARD EVENING. THE FRONTAL
BOUNDARY COMBINED WITH A DECENT WAVE AS SEEN ON WV IMAGERY IN
AZ...WILL LIFT NORTHEAST AHEAD OF THE MEAN UPPER TROUGH IN THE
PACIFIC NORTHWEST AND AID IN INITIATING ANOTHER ROUND OF
CONVECTION LATER TODAY/TONIGHT. HIGH INSTABILITY WILL EXIST ALONG
AND NORTH OF THE FRONT WITH 4000 J/KG EXPECTED FM THE NEB/KS
STATELINE NORTHWARD INTO SOUTHERN NEB. SHEAR PARAMETERS IN GENERAL
AVERAGE 30KTS BUT INCREASE OVER 30KTS ACROSS OUR WESTERN ZONES IN
CLOSER PROXIMITY TO THE SURFACE LOW. MODELS SUGGEST THE BRUNT OF
THE CONVECTION WILL BE ACROSS WESTERN NEBRASKA AND KANSAS...BUT
THE FRONTAL BOUNDARY HAS BEEN ACTIVE THE LAST COUPLE OF DAYS AND
BELIEVE THIS WILL BE THE CASE TODAY. WITH THE HIGH
INSTABILITY...GOOD SHEAR AND BOUNDARY IN PLACE...CONDITIONS WILL
BE FAVORABLE FOR SEVERE THUNDERSTORMS WITH LARGE HAIL OF GOLF BALL
SIZE OR GREATER POSSIBLE AND DAMAGING TSTM WIND GUSTS. CANNOT RULE
OUT THE POTENTIAL FOR A TORNADO ESPECIALLY IN THE VICINITY OF THE
FRONT OR NEAR SFC LOW. HIGH DPS AND PRECIPITABLE WATER VALUES OF
AN IN INCH AND A HALF TO TWO INCHES WILL BRING THE POSSIBILITY OF
VERY HEAVY RAINFALL/LOCALIZED FLOODING ESPECIALLY FOR LOCATIONS
WHICH HAVE RECEIVED DECENT RAINFALL AMOUNTS THE LAST COUPLE OF
DAYS. FFG IS STILL IN THE 2 TO 3 INCH RANGE SO NOT LOOKING FOR A
LOT OF HYDRO ISSUES JUST YET.
AFTERNOON TEMPERATURES WILL BE TOASTY SOUTH OF THE WARM FRONT IN
KANSAS WITH READINGS WELL INTO THE 90S TO AROUND 100F...WHILE TO
THE NORTH OF THE FRONT UPPER 80S TO LOW 90S ARE FORECAST.
THE WARM FRONTAL BOUNDARY WILL LIFT NORTH TONIGHT WITH THE
PROGRESSING UPPER WAVE...AND THE NOSE OF A 40KT LLVL JET ORIENTS
ACROSS NORTHERN AND EASTERN NEB. THE THUNDERSTORMS ARE EXPECTED TO
INCREASE IN COVERAGE ALONG/NORTH OF THE FRONT DURING THE EVENING
BEFORE LIFTING INTO NORTHERN NEB OVERNIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 320 AM CDT FRI
AUG 22 2014
ALOFT: AMPLIFIED SW FLOW WILL DOMINATE THRU TUE WITH A TROF OVER THE
WRN USA. THE MOST DYNAMIC EMBEDDED SHORTWAVE TROF WILL EJECT ACROSS
THE NRN PLAINS SUN LEAVING A +TILT REMNANT TROF REMAINING IN ITS
WAKE. THIS TROF WILL BECOME PROGRESSIVE AND SLIDE THRU HERE TUE-WED
WITH DEAMPLIFICATION. THE EC/GEM/GFS/UKMET ARE IN GOOD AGREEMENT.
AS FOR THE SHORTER WAVELENGTHS...PLEASE SEE THE 1213 AM MODEL
DIAGNOSTIC DISCUSSION /PMDHMD/ FOR DETAILED MODEL ASSESSMENT. THE
LOW CURRENTLY OVER THE DESERT SW WILL OPEN UP AND LIFT THRU HERE
SAT. THE DIGGING/POTENT LOW OVER THE NRN ROCKIES WILL TAKE ON -TILT
SUN /JUST NW OF THE FCST AREA/ AS AN 80 KT UPPER-LVL JET SWINGS
AROUND ITS BASE. WSW FLOW FOLLOWS MON-TUE WITH THE LAGGING TROF
MOVING THRU LATE TUE. SUBSIDENT NW FLOW MAY MOVE IN WED-THU. THE
12Z/00Z GEM AND NOW THE 00Z EC CUT-OFF A LOW AT THE BASED OF THE
TROF WITH THE WESTERLIES BECOMING RE-ESTABLISHED OVER CANADA.
SURFACE: LOW PRES AND A CONVECTIVELY ACTIVE WARM FRONT WILL BE
LIFTING THRU THE FCST AREA SAT. A WEAK COOL FRONT WILL SLIDE THRU
BEHIND IT SUN. A STRONGER SECONDARY FRONT WILL FOLLOW SUN NIGHT.
THIS FRONT WILL BECOME STATIONARY ALONG THE KS-NEB BORDER MON UNTIL
THE UPPER TROF MOVES THRU...SHOVING THE FRONT DOWN INTO THE SRN
PLAINS TUE. CANADIAN HIGH PRES WILL ARRIVE WED WITH RETURN FLOW
AND A NEW LEE-SIDE TROF DEVELOPING THU.
HAZARDS: MULTIPLE EPISODES OF TSTMS ARE POSSIBLE SAT-TUE. HEAT
BURSTS COULD BE A PROBLEM SAT NIGHT. AS OF NOW THERE ARE NO OBVIOUS
THREATS OF SEVERE TSTMS...BUT THERE CERTAINLY WILL BE POTENTIAL.
THE DAILY DETAILS...
SAT: OVERNIGHT TSTM ACTIVITY SHOULD BE OFF TO THE N BY DAYBREAK.
DOESNT LOOK LIKE MUCH LOW-LVL FORCING TO INITIATE AFTERNOON TSTMS
AND THE LOW-LVL MOIST TONGUE WILL LIFT N WITH THE WARM FRONT. FCST
NAM/EC/GFS SOUNDINGS MINIMAL CAPPING THOUGH. WE MAY ALSO BE TOO HIGH
ON OUR FCST DWPTS BY 5F. FOR NOW HAVE A SLIGHT CHANCE OF A TSTM
AFTER 4 PM. IF TSTMS DEVELOP THEY WILL BE HIGH-BASED AND GUSTY WITH
CONVECTIVE CONDENSATION LVLS AROUND 10K FT.
BREEZY FROM HWY 281 E AS MIXING RESULTS IN DOWNWARD TRANSFER OF THE
LLJ.
SAT NIGHT: STRONG CONVERGENCE AS THE COOL FRONT MOVES IN. AGAIN TSTM
INITIATION IS HIGHLY UNCERTAIN. SO ONLY HAVE A SLIGHT CHANCE POP IN
THE FCST. WITH SKINNY CAPE ABOVE 10K FT AND AN INVERT-V LOOK TO THE
SOUNDINGS...HAVE TO WONDER IF HEAT BURSTS MAY BE A PROBLEM "IF"
TSTMS CAN DEVELOP.
SUN: COOL FRONTAL PASSAGE WITH COOL/DRY AIR ADVECTION. TEMPS DROP
BACK TO NEAR NORMAL. LOOKING VERY NICE AND COMFORTABLE FOR OUTDOOR
ACTIVITIES.
SUN NIGHT: UPSLOPE FLOW COULD RESULT IN TSTMS JUST TO THE W OF THE
FCST AREA. THE FCST COULD BE OVERDONE ON POPS. THE EC/GFS DO NOT
AGREE ON THE LOCATION OF THE FRONT. BELIEVE THE EC/GEM FURTHER S
POSITION IS BEST GIVEN THE STRENGTH OF THE SYSTEM ALOFT.
MON: WEAK LEE CYCLOGENESIS RESULT IN THE FRONT LIFTING BACK N.
SUBSTANTIAL TSTM/MCS ACTIVITY EXPECTED MON NIGHT AS THE LLJ IMPINGES
ON THE FRONT AND WAA/FRONTOGENESIS DEVELOP.
THIS HAS HEAVY RAIN POTENTIAL WRITTEN ON IT. GEM/EC/GFS QPF IS
IMPRESSIVE WITH POCKETS OF 1-3".
TUE: BELOW AVERAGE CONFIDENCE ON TEMPS. THERE COULD BE SUBSTANTIAL
CLOUD COVER UNDERNEATH THE FRONT. CANT RULE OUT MORE TSTM ACTIVITY
INTO TUE NIGHT AS THE STRONGER COOL FRONT MOVES IN.
WED-THU: FAIR AND DRY. HOWEVER...WE ARE CARRYING A SLIGHT CHANCE OF
TSTMS WED. THIS PROBABLY IS OVERDONE. COMFORTABLY BELOW NORMAL WED
WITH TEMPS RETURNING TO NORMAL THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1216 AM CDT FRI AUG 22 2014
AT FIRST GLANCE...CONVECTION DURING THE REMAINDER OF THE NIGHT
SHOULD REMAIN TO THE EAST OF THE TERMINALS BUT A HIT OR MISS STORM
MAY STILL DEVELOP PRIMARILY TOWARDS KGRI IN THE VCNTY OF A LLVL
BOUNDARY. WITH FAIRLY LIGHT WINDS AND IN PRESENCE OF LLVL MOISTURE
FOG DEVELOPMENT IS POSSIBLE TOWARD MORNING WITH THE HRRR THE MOST
ROBUST WITH DEVELOP ALONG THE PLATTE RIVER AND MORE SO FOR KGRI VS
KEAR. WILL CONTINUE TO MONITOR TRENDS FOR THIS. A WARM FRONTAL
BOUNDARY IS PROGGED TO STALL SOUTH OF THE TERMINALS THIS AFTERNOON
THEN LIFT NORTHWARD THIS EVENING AND TONIGHT. THE FRONT WILL AGAIN
BE THE FOCUS FOR SHOWERS AND STORMS AND SEVERE WEATHER IS
POSSIBLE. BEST TIMING FOR CONVECTION IS DURING THE LATTER TAF
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...HALBLAUB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1222 AM CDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 700 PM CDT THU AUG 21 2014
THE 18Z NAM HAS FAILED TO CAPTURE THE ONGOING CONVECTION ACROSS
OUR SOUTHEASTERN FORECAST AREA AND IS ESSENTIALLY DRY THROUGH
MIDNIGHT. HOWEVER...THE HRRR MODEL SEEMS TO BE CATCHING ONTO
THINGS AND HAS BEEN GIVING FAIRLY REALISTIC SCENARIOS FOR HOW
THUNDERSTORMS WILL EVOLVE THIS EVENING. BASED ON RADAR AND THE
HRRR HAVE INCREASED POPS INTO THE LIKELY CATEGORY FOR MOST OF OUR
KANSAS COUNTIES INTO NUCKOLLS...THAYER...AND FILLMORE COUNTIES.
ALSO SLIGHTLY INCREASED POPS NORTH OF THE RADAR FINE LINE BOUNDARY
THAT AT 7 PM WAS RUNNING FROM PHILLIPSBURG...TO BLUE HILL. THE LOW
LEVEL JET WILL INCREASE THIS EVENING WITH THE NOSE OF THE JET
RUNNING INTO OUR SOUTHERN FORECAST AREA. THE HRRR INDICATES THAT
THUNDERSTORMS COULD FORM NORTH OF THE EXISTING THUNDERSTORMS LATER
THIS EVENING IN PLACES LIKE HASTINGS AS THE LOW LEVEL JET
INCREASES...BUT CONFIDENCE IN THIS IS STILL LESS THAN 50 PERCENT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 341 PM CDT THU AUG 21 2014
MAP ANALYSIS INDICATES AN UPPER TROPOSPHERIC RIDGE OVER THE
CENTRAL CONUS...WITH TROUGHS OVER THE WESTERN AND EASTERN CONUS.
MAP ANALYSIS ALSO SHOWS A CLOSED UPPER TROPOSPHERIC LOW EMBEDDED
WITHIN THE BASE OF THE WESTERN CONUS TROUGH. ENHANCED UPPER
TROPOSPHERIC ENERGY EXTENDS FROM NORTH TO SOUTH ALONG THE WESTERN
CONUS COAST...THEN NORTHEAST INTO THE NORTHERN PLAINS...AND
FINALLY BACK TO THE SOUTHEAST ACROSS THE GREAT LAKES REGION. THAT
BEING SAID...UPPER TROPOSPHERIC FLOW OVER OUR AREA REMAINS FAIRLY
WEAK...ONLY MAXING OUT AT AROUND 35KTS NEAR 38000FT AGL PER RAP
ANALYSIS DATA AT 12Z. WATER VAPOR IMAGERY ALSO SHOWS THE
AFOREMENTIONED RIDGE AND TROUGHS...AS WELL AS ENHANCED UPPER
TROPOSPHERIC MOISTURE EXTENDING FROM HURRICANE LOWELL INTO THE
SOUTHWESTERN CONUS. THIS TROPICAL MOISTURE HAS YET TO REACH THE
CENTRAL PLAINS HOWEVER. AT THE SURFACE AN AREA OF LOW BAROMETRIC
PRESSURE EXISTS OVER SOUTHWESTERN MINNESOTA...AND AN ASSOCIATED
SURFACE TROUGH EXTENDS SOUTHWEST FROM THE LOW INTO NEBRASKA AND
KANSAS. AS OF 18Z THIS TROUGH WAS NOTED EXTENDING FROM NEAR
KODX...TO NEAR KHDE...TO NEAR KHLC. THE RESULTANT LOWER
TROPOSPHERIC WIND FIELD ACROSS OUR AREA REMAINS FROM THE SOUTH
ACROSS EASTERN PORTIONS OF OUR CWA...BUT LOCATIONS FARTHER
WEST/NORTHWEST...BEHIND THE TROUGH...ARE NOW REPORTING A NORTHERLY
COMPONENT TO THE LOWER TROPOSPHERIC WIND FIELD.
GUIDANCE SUGGESTS THE CLOSED UPPER TROPOSPHERIC LOW OVER THE
WESTERN CONUS WILL EJECT FROM THE BASE OF THE LONG WAVE TROUGH AS
A SHORT WAVE TONIGHT INTO FRIDAY...LIKELY MOVING INTO THE FOUR
CORNERS REGION BY 00Z SATURDAY. AS A RESULT...SURFACE CYCLOGENESIS
THEN EXPECTED OVER WESTERN KANSAS FRIDAY AFTERNOON. SO ALTHOUGH
THE SURFACE TROUGH...CURRENTLY LOCATED OVER OUR AREA...WILL MAKE
AN ATTEMPT TO MOVE EAST ACROSS THE AREA TONIGHT...THE TROUGH
SHOULD EVENTUALLY BECOME STATIONARY IF NOT RETROGRADE SOMEWHAT AS
IT STRENGTHENS INTO A WARM FRONT IN RESPONSE TO THE WESTERN KANSAS
CYCLOGENESIS. THE LOWER TROPOSPHERIC WIND FIELD ACROSS THE
SOUTH/SOUTHEASTERN ONE-HALF OF THE CWA WILL LIKELY REMAIN FROM THE
SOUTH/SOUTHEAST THROUGH THE NEXT 24 HOURS...BUT LOCATIONS FARTHER
NORTHWEST WILL LIKELY EXPERIENCE MORE OF A NORTHEASTERLY WIND
FIELD.
ANY OMEGA DERIVED FROM UPPER TROPOSPHERIC KINEMATICS SHOULD
REMAIN ON THE WEAK SIDE THROUGH MUCH OF THE SHORT TERM FORECAST
PERIOD. THAT BEING SAID...GUIDANCE DOES SUGGEST THE AXIS OF A
~50KT LOWER TROPOSPHERIC JET STREAK JUST ABOVE THE BOUNDARY LAYER
WILL DEVELOP FROM CENTRAL KANSAS INTO SOUTHEASTERN NEBRASKA
TONIGHT...BEFORE SHIFTING OFF TO THE EAST SOMEWHAT BY DAYBREAK
FRIDAY. THERMAL ADVECTION ALONG THIS AXIS...AS WELL AS MOISTURE
CONVERGENCE NEAR THE NOSE OF THE JET STREAK...SHOULD BE SUFFICIENT
FOR PRECIPITATION PRODUCTION...ESPECIALLY ACROSS OUR SOUTHEASTERN
CWA...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS AND EC...AS WELL AS SIMULATED REFLECTIVITY
FROM THE HRRR. GIVEN ALL THIS...WENT AHEAD WITH 20-30% POPS ACROSS
MUCH OF THE CWA FOR TONIGHT...WITH THE HIGHEST POPS RELEGATED TO
THE SOUTHEASTERN CWA.
ANY PRECIPITATION THAT DOES DEVELOP TONIGHT SHOULD MOVE OFF TO
THE EAST BY SUNRISE FRIDAY AS THE AXIS OF THE LOWER TROPOSPHERIC
JET STREAK DOES THE SAME. THIS SHOULD PROVIDE A BREAK IN THE
PRECIPITATION ACROSS OUR AREA FRIDAY MORNING INTO LATE FRIDAY
AFTERNOON.
BY LATE FRIDAY AFTERNOON AND INTO FRIDAY EVENING
HOWEVER...THERMAL ADVECTION AHEAD OF THE APPROACHING UPPER
TROPOSPHERIC SHORT WAVE SHOULD PROMOTE INCREASING OMEGA ACROSS THE
REGION. THIS OMEGA...WORKING IN CONCERT WITH ENHANCED LOWER
TROPOSPHERIC CONVERGENCE ALONG THE STRENGTHENING BAROCLINIC
ZONE...MAY BE SUFFICIENT FOR THE DEVELOPMENT OF ISOLATED TO
PERHAPS SCATTERED SHOWER AND THUNDERSTORM ACTIVITY. THIS IS A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS
AND EC. GIVEN ALL THIS..WENT AHEAD WITH 20-50% POPS ACROSS THE CWA
FRIDAY AFTERNOON AND EVENING...WITH THE HIGHEST POPS RELEGATED TO
CENTRAL AND NORTHERN PORTIONS OF THE CWA IN CLOSEST PROXIMITY TO
THE LOWER TROPOSPHERIC BAROCLINIC ZONE.
FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS THE CWA...PER THE
NAM AND OPERATIONAL GFS...SUGGEST PARCELS ROOTED TO AROUND 800MB
SHOULD HAVE 500-1000J/KG WITH ANY CONVECTION THAT IS REALIZED
TONIGHT. GIVEN THIS...WILL GO AHEAD AND OUTLOOK THE POSSIBILITY
FOR LARGE HAIL AND STRONG WIND GUSTS IN THE HWO FOR TONIGHT.
TURNING TO FRIDAY AFTERNOON AND EVENING...THE NAM...OPERATIONAL
GFS AND EC SUGGEST 0-1KM MLCAPE VALUES OF 1000-3000J/KG WILL BE IN
EXISTENCE WITH DEEP-LAYER BULK SHEAR VALUES OF 15-30KTS. GIVEN
THIS...SEVERE WEATHER IS A DEFINITE POSSIBILITY WITH ANY
THUNDERSTORM THAT DOES DEVELOP AND AS A RESULT...WILL GO AHEAD AND
OUTLOOK LARGE HAIL AND STRONG WIND IN THE HWO FOR LATE FRIDAY
AFTERNOON AND FRIDAY EVENING. ALSO...LOCALLY ENHANCED LOWER
TROPOSPHERIC HORIZONTAL VORTICITY ALONG THE AXIS OF THE BAROCLINIC
ZONE COULD PROMOTE A THREAT FOR ISOLATED TORNADOES WITH ANY STORM
THAT CAN LATCH ONTO THE BOUNDARY. GIVEN THIS...WILL ALSO OUTLOOK
THE THREAT FOR ISOLATED TORNADIC ACTIVITY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 341 PM CDT THU AUG 21 2014
FRIDAY EVENING THROUGH THURSDAY. FORECAST CONCERN IN THE EXTENDED
CENTERS ON CONTINUING RAIN CHANCES ALONG WITH SLIGHT COOLING
TREND.
BEGINNING FRIDAY EVENING...MODELS CONSISTENT WITH BIG PICTURE AS
THEY HAVE AN UPPER LEVEL RIDGE OVER THE MISSISSIPPI RIVER VALLEY
AND A LOW CENTERED OVER NORTH CENTRAL IDAHO. THE LOW OVER SOUTHERN
CALIFORNIA AT PRESENT IS FORECAST TO EJECT OUT AHEAD OF THE MAIN
PACIFIC NW CLOSED LOW AS A SHORTWAVE TROUGH AND SHOULD MOVE
NORTHEAST AFFECTING THE CENTRAL PLAINS LATE FRIDAY EVENING. IT
SHOULD HELP LIFT A SURFACE LOW AND ASSOCIATED WARM FRONT NORTH
THROUGH NEB OVERNIGHT. THE NAM AND GFS STILL DIFFER SOME ON THE
LOCATION BUT ARE SIMILAR IN LIFTING THE PRECIPITATION FROM OUR CWA
INTO NORTHERN NEB OVERNIGHT. HEAVY RAIN IS POSSIBLE AS THE SYSTEM
MOVES SLOWLY NORTH WITH PLENTY OF MOISTURE AVAILABLE. THE KS
PORTION OF OUR CWA MAY REMAIN CAPPED AND MISS OUT ON THE
ACTION...DEPENDING WHERE THE THUNDERSTORMS FIRST FIRE UP. ML-CAPE
AND DEEP LAYER SHEAR APPEAR HIGH ENOUGH FOR SEVERE STORMS INTO THE
EVENING...ALTHOUGH BETTER SHEAR PROGGED TO BE IN THE WESTERN PART
OF NEB AS OF NOW. DECENT LOW LEVEL JET OF 30-40 KT ALSO FORECAST
TO DEVELOP AND RIDE OVER WARM FRONT WHICH SHOULD HELP SUSTAIN
STORMS. PLAN TO TRIM POPS FROM SOUTH TO NORTH OVERNIGHT.
RAIN CHANCES SHOULD CONTINUE FOR THE WEEKEND WITH THE BEST TIME
FRAME FOR RAIN BEING LATE AFTERNOON INTO THE NIGHT. THE UPPER
TROUGH IS EXPECTED TO MOVE A BIT EASTWARD PUTTING US IN SOUTHWEST
FLOW. MEANWHILE A COLD FRONT SHOULD STALL OUT AS IS BECOMES
PARALLEL TO THE UPPER FLOW AND SHOULD BE SITUATED FROM THE EASTERN
DAKOTAS TO SOUTHWEST KANSAS. RAIN CHANCES WILL DEPEND ON SEVERAL
FACTORS INCLUDING FRONTAL CONVERGENCE...LOW LEVEL JET
DEVELOPMENT...SHORTWAVE TROUGHS MOVING THROUGH...ETC. ONE THING
THAT WILL NOT BE A CONCERN IS MOISTURE AS PRECIPITABLE WATER
VALUES AVERAGE 150 PERCENT OF NORMAL DUE TO A GOOD SUBTROPICAL
TAP.
AS NOTED IN PREVIOUS AFD...RAIN CHANCES CONTINUE INTO THE EARLY
PART OF NEXT WEEK AS THE UPPER TROUGH REMAINS WEST OF US AND
VARIOUS SURFACE BOUNDARIES STALL OUT OVER THE AREA. THE LATEST GFS
OPERATIONAL RUN IS MOVING IT THROUGH A LITTLE FASTER AS IT NOW HAS
THE 500 MB TROUGH AXIS PASSING OUR CWA NEXT WED AFTERNOON. EC HAS
ALSO COME IN LINE WITH THIS SOLUTION AND IS ACTUALLY ABOUT 12
HOURS FASTER THAN THE GFS. THIS A QUITE A DIFFERENCE FROM PREVIOUS
EC WHICH DROPPED A SECOND LOW SOUTH BEHIND THE FIRST ONE AND DIDNT
CLEAR THE SECOND LOW UNTIL NEXT SATURDAY. WILL HAVE TO KEEP AN EYE
ON HOW THIS CHANGES OVER THE NEXT FEW DAYS...BUT IF LATEST
SOLUTIONS ARE ON TRACK...COULD SEE THINGS DRY OUT A BIT NEXT WED
INTO AT LEAST FRIDAY WHICH WOULD BE WELCOME NEWS FOR NEB STATE
FAIR ATTENDEES.
REGARDING TEMPERATURES...SOME COOLING EXPECTED ON SUNDAY WITH
PASSAGE OF WEAK COLD FRONT AND THEN AGAIN ON WEDNESDAY AS MAIN
TROUGH AND ANOTHER FRONT MOVES THROUGH. EXPECT HIGH TO BE IN THE
LOWER 80S NORTH TO LOWER 90S SOUTH ON AVERAGE...ONCE AGAIN
DEPENDING ON WHERE VARIOUS FRONTS STALL OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1216 AM CDT FRI AUG 22 2014
AT FIRST GLANCE...CONVECTION DURING THE REMAINDER OF THE NIGHT
SHOULD REMAIN TO THE EAST OF THE TERMINALS BUT A HIT OR MISS STORM
MAY STILL DEVELOP PRIMARILY TOWARDS KGRI IN THE VCNTY OF A LLVL
BOUNDARY. WITH FAIRLY LIGHT WINDS AND IN PRESENCE OF LLVL MOISTURE
FOG DEVELOPMENT IS POSSIBLE TOWARD MORNING WITH THE HRRR THE MOST
ROBUST WITH DEVELOP ALONG THE PLATTE RIVER AND MORE SO FOR KGRI VS
KEAR. WILL CONTINUE TO MONITOR TRENDS FOR THIS. A WARM FRONTAL
BOUNDARY IS PROGGED TO STALL SOUTH OF THE TERMINALS THIS AFTERNOON
THEN LIFT NORTHWARD THIS EVENING AND TONIGHT. THE FRONT WILL AGAIN
BE THE FOCUS FOR SHOWERS AND STORMS AND SEVERE WEATHER IS
POSSIBLE. BEST TIMING FOR CONVECTION IS DURING THE LATTER TAF
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...BRYANT
LONG TERM...EWALD
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
943 AM PDT FRI AUG 22 2014
.SYNOPSIS...A FEW LINGERING THUNDERSTORMS MAY OCCUR OVER NORTHWEST
ARIZONA TODAY BEHIND A CIRCULATION MOVE TOWARD THE FOUR CORNERS
REGION. A BROAD AREA OF LOW PRESSURE BRUSHING NORTHERN NEVADA WILL
LEAD TO DRY SOUTHWEST FLOW WITH TEMPERATURES A LITTLE BELOW NORMAL
ACROSS THE ENTIRE REGION THROUGH THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...THE LATEST OBSERVATIONS AND MODEL DATA SUPPORT THE GOING
FORECAST AND NO IMMEDIATE CHANGES ARE NEEDED. THE 12Z LAS VEGAS
SOUNDING SHOWED SIGNIFICANT WARMING AROUND 500 MB WHICH SHOULD KEEP
A STRONG ENOUGH CAP TO INHIBIT CONVECTION OVER SOUTHERN NEVADA AND
SOUTHEAST CALIFORNIA EVEN THOUGH MOISTURE WILL BE SLOW TO SCOUR OUT
TODAY. THERE WILL STILL BE ENOUGH INSTABILITY FOR ISOLATED
HEATING/TERRAIN DRIVEN THUNDERSTORMS OVER MOHAVE COUNTY.
RECENT SATELLITE LOOPS SHOW SUBSTANTIAL MOISTURE OVER NORTHEAST
NEVADA AHEAD OF A DIGGING TROUGH. THIS WILL BRUSH FAR NORTHERN
LINCOLN COUNTY BY THIS EVENING WITH SHOWERS AND THUNDERSTORMS. THE
TROUGH WILL INFLUENCE THE REST OF THE REGION WITH INCREASING
SOUTHWEST BREEZES THIS AFTERNOON.
&&
.PREV DISCUSSION...
255 AM PDT FRI AUG 22 2014
.SHORT TERM...THROUGH SUNDAY NIGHT
UPPER LOW OVER SOUTHWEST ARIZONA NOW WILL LIFT NORTHEAST INTO THE
FOUR CORNERS THIS AFTERNOON IN RESPONSE TO TROUGH DIGGING INTO THE
PACIFIC NORTHWEST. REGIONAL RADAR SHOWS SOME LIGHT RAIN AROUND
FLAGSTAFF WITH NOTHING IN OUR FORECAST AREA. HRRR SUGGESTS
CONVECTION WILL GET ANOTHER EARLY START (BY 10 AM) OVER THE HIGHER
TERRAIN OF SOUTHERN MOHAVE COUNTY WHERE SUFFICIENT
MOISTURE/INSTABILITY REMAIN. IT WILL BE MUCH QUIETER ACROSS
SOUTHEAST NEVADA AND EASTERN SAN BERNARDINO COUNTY AS SOME DRYING
AND STABILIZATION OF THE AIR MASS OCCURS. FOR FAR NORTHERN LINCOLN
COUNTY, MODELS CONTINUE TO INDICATE THE POTENTIAL OF SOME
SHOWERS/THUNDERSTORMS IN PROXIMITY OF A STATIONARY FRONT OVER
CENTRAL NEVADA. ON SATURDAY, THE ONLY MENTIONABLE POPS ARE ACROSS
NORTHEAST LINCOLN AGAIN NEAR THE STATIONARY FRONT. ELSEWHERE, DRYING
FROM THE WEST WILL OCCUR OVER THE WEEKEND. DUE TO THE APPROACHING
TROUGH SOUTH/SOUTHWEST WINDS WILL INCREASE ACROSS THE WESTERN MOJAVE
DESERT AND SOUTHERN GREAT BASIN THIS AFTERNOON BUT WILL REMAIN BELOW
ADVISORY CRITERIA. HI RES MODELS ALSO SHOWING A WEAK DOWNSLOPE EVENT
ALONG THE EASTERN SIERRA SLOPES SAY BETWEEN 3 PM AND 10 PM THIS
EVENING. PLEASANT TEMPERATURES TO THE START EACH DAY WHILE DAYTIME
HIGHS WILL CONTINUE TO RUN AROUND 3 TO 6 DEGREES BELOW NORMAL.
.LONG TERM...MONDAY THROUGH FRIDAY NIGHT.
AFTER FLYING SOLO LAST NIGHT, THE OPERATIONAL ECMWF RETURNED BACK TO
A PROGNOSTICATION MORE SIMILAR TO WHAT IT HAD BEEN SHOWING ON
PREVIOUS MODEL RUNS FOR EARLY NEXT WEEK. THIS PUTS IT IN MUCH BETTER
AGREEMENT WITH THE OTHER OPERATIONAL MODELS AND THE VAST MAJORITY OF
THE GFS ENSEMBLE MEMBERS WITH HOW IT HANDLES THE UPCOMING PATTERN.
THE NEXT MID/UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHEAST ACROSS
NEVADA MONDAY AFTERNOON INTO MONDAY NIGHT AND INTO UTAH BY TUESDAY.
THE 00Z OPERATIONAL GFS WAS MORE SHALLOW WITH THE TROUGH THAN THE
GEM AND ECMWF SO THE FORECAST SHOWS A BLEND BETWEEN THE TWO. UNLESS
THIS TROUGH ENTRAINS ENOUGH SUBTROPICAL MOISTURE INTO IT, IT SHOULD
PASS ON BY WITH LITTLE MORE THAN SOME HIGH CLOUDS AND PERHAPS SOME
ENHANCED WINDS. TEMPS SHOULD BE HELD DOWN A FEW DEGREES BELOW NORMAL
DUE TO THE LOWER HEIGHTS, BY WEDNESDAY INTO THURSDAY, A RIDGE ALOFT
IS SHOWN TO BUILD IN FROM THE WEST WHICH SHOULD YIELD A WARMING
TREND WITH HIGHS EDGING BACK TO OR A LITTLE ABOVE NORMAL. THIS RIDGE
EITHER LOOKS TO GET STRETCHED OUT OR SHUNTED EAST BY FRIDAY AS
ANOTHER MID/UPPER LEVEL TROUGH SLICES ACROSS NORCAL AND NORTHERN
NEVADA. EITHER WAY, THERE DOES NOT LOOK TO BE ANY GREAT SIGN FOR
MONSOON MOISTURE TO MAKE A RETURN BACK ON IN, SO THE FORECAST
REMAINS DRY. TEMPS WERE A BLEND OF BIAS CORRECTED CONS MODELS WITH A
LITTLE ECMWF AND MEX MOS MIXED ON IN.
&&
.AVIATION...FOR MCCARRAN...A SOUTHEAST WIND COMPONENT CAN BE
EXPECTED DURING THE LATE MORNING AND EARLY AFTERNOON BEFORE WINDS
INCREASE FROM THE SOUTHWEST WITH GUSTS UP TO 25 KTS AFTER 22Z AND
PERSIST INTO THE EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A DRY SOUTHWEST FLOW WILL START TO SPREAD ACROSS MOST
OF THE REGION TODAY WITH ANY THREAT OF THUNDERSTORMS CONFINED TO THE
HIGHER TERRAIN OF MOHAVE COUNTY. SKIES WILL BE MOSTLY CLEAR
ELSEWHERE. SOUTHWEST WINDS GUSTING AROUND 30 KNOTS THIS AFTERNOON IN
THE WESTERN MOJAVE DESERT AND SOUTHERN GREAT BASIN.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
AT THIS TIME.
&&
$$
UPDATE/AVIATION...ADAIR
PREV DISCUSSION...PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
255 AM PDT FRI AUG 22 2014
.SYNOPSIS...A CIRCULATION OVER SOUTHWEST ARIZONA WILL CONTINUE
TOWARD THE FOUR CORNERS REGION TODAY. A FEW LINGERING STORMS MAY
OCCUR OVER NORTHWEST ARIZONA. A BROAD AREA OF LOW PRESSURE
BRUSHING NORTHERN NEVADA WILL LEAD TO DRY CONDITIONS WITH
TEMPERATURES A LITTLE BELOW NORMAL ACROSS THE ENTIRE REGION THROUGH
THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...THROUGH SUNDAY NIGHT
UPPER LOW OVER SOUTHWEST ARIZONA NOW WILL LIFT NORTHEAST INTO THE
FOUR CORNERS THIS AFTERNOON IN RESPONSE TO TROUGH DIGGING INTO THE
PACIFIC NORTHWEST. REGIONAL RADAR SHOWS SOME LIGHT RAIN AROUND
FLAGSTAFF WITH NOTHING IN OUR FORECAST AREA. HRRR SUGGESTS
CONVECTION WILL GET ANOTHER EARLY START (BY 10 AM) OVER THE HIGHER
TERRAIN OF SOUTHERN MOHAVE COUNTY WHERE SUFFICIENT
MOISTURE/INSTABILITY REMAIN. IT WILL BE MUCH QUIETER ACROSS
SOUTHEAST NEVADA AND EASTERN SAN BERNARDINO COUNTY AS SOME DRYING
AND STABILIZATION OF THE AIR MASS OCCURS. FOR FAR NORTHERN LINCOLN
COUNTY, MODELS CONTINUE TO INDICATE THE POTENTIAL OF SOME
SHOWERS/THUNDERSTORMS IN PROXIMITY OF A STATIONARY FRONT OVER
CENTRAL NEVADA. ON SATURDAY, THE ONLY MENTIONABLE POPS ARE ACROSS
NORTHEAST LINCOLN AGAIN NEAR THE STATIONARY FRONT. ELSEWHERE, DRYING
FROM THE WEST WILL OCCUR OVER THE WEEKEND. DUE TO THE APPROACHING
TROUGH SOUTH/SOUTHWEST WINDS WILL INCREASE ACROSS THE WESTERN MOJAVE
DESERT AND SOUTHERN GREAT BASIN THIS AFTERNOON BUT WILL REMAIN BELOW
ADVISORY CRITERIA. HI RES MODELS ALSO SHOWING A WEAK DOWNSLOPE EVENT
ALONG THE EASTERN SIERRA SLOPES SAY BETWEEN 3 PM AND 10 PM THIS
EVENING. PLEASANT TEMPERATURES TO THE START EACH DAY WHILE DAYTIME
HIGHS WILL CONTINUE TO RUN AROUND 3 TO 6 DEGREES BELOW NORMAL.
.LONG TERM...MONDAY THROUGH FRIDAY NIGHT.
AFTER FLYING SOLO LAST NIGHT, THE OPERATIONAL ECMWF RETURNED BACK TO
A PROGNOSTICATION MORE SIMILAR TO WHAT IT HAD BEEN SHOWING ON
PREVIOUS MODEL RUNS FOR EARLY NEXT WEEK. THIS PUTS IT IN MUCH BETTER
AGREEMENT WITH THE OTHER OPERATIONAL MODELS AND THE VAST MAJORITY OF
THE GFS ENSEMBLE MEMBERS WITH HOW IT HANDLES THE UPCOMING PATTERN.
THE NEXT MID/UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHEAST ACROSS
NEVADA MONDAY AFTERNOON INTO MONDAY NIGHT AND INTO UTAH BY TUESDAY.
THE 00Z OPERATIONAL GFS WAS MORE SHALLOW WITH THE TROUGH THAN THE
GEM AND ECMWF SO THE FORECAST SHOWS A BLEND BETWEEN THE TWO. UNLESS
THIS TROUGH ENTRAINS ENOUGH SUBTROPICAL MOISTURE INTO IT, IT SHOULD
PASS ON BY WITH LITTLE MORE THAN SOME HIGH CLOUDS AND PERHAPS SOME
ENHANCED WINDS. TEMPS SHOULD BE HELD DOWN A FEW DEGREES BELOW NORMAL
DUE TO THE LOWER HEIGHTS, BY WEDNESDAY INTO THURSDAY, A RIDGE ALOFT
IS SHOWN TO BUILD IN FROM THE WEST WHICH SHOULD YIELD A WARMING
TREND WITH HIGHS EDGING BACK TO OR A LITTLE ABOVE NORMAL. THIS RIDGE
EITHER LOOKS TO GET STRETCHED OUT OR SHUNTED EAST BY FRIDAY AS
ANOTHER MID/UPPER LEVEL TROUGH SLICES ACROSS NORCAL AND NORTHERN
NEVADA. EITHER WAY, THERE DOES NOT LOOK TO BE ANY GREAT SIGN FOR
MONSOON MOISTURE TO MAKE A RETURN BACK ON IN, SO THE FORECAST
REMAINS DRY. TEMPS WERE A BLEND OF BIAS CORRECTED CONS MODELS WITH A
LITTLE ECMWF AND MEX MOS MIXED ON IN.
&&
.AVIATION...FOR MCCARRAN...PREVAILING WIND DIRECTION WILL BE FROM
THE SOUTH THROUGH THE MORNING. DRIER AIR ARRIVES TODAY ALTHOUGH
SOUTHWEST WINDS WILL INCREASE WITH GUSTS UP TO 25 KTS POSSIBLE.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A DRY SOUTHWEST FLOW WILL START TO SPREAD ACROSS MOST
OF THE REGION TODAY WITH ANY THREAT OF THUNDERSTORMS CONFINED TO THE
HIGHER TERRAIN OF MOHAVE COUNTY. SKIES WILL BE MOSTLY CLEAR
ELSEWHERE. SOUTHWEST WINDS GUSTING AROUND 30 KNOTS THIS AFTERNOON IN
THE WESTERN MOJAVE DESERT AND SOUTHERN GREAT BASIN.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
AT THIS TIME.
&&
$$
PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1014 PM EDT SAT AUG 23 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TONIGHT...ACCOMPANIED
BY SHOWERS AND A FEW THUNDERSTORMS. PROGRESSIVELY DRIER AND COOLER
AIR WILL BUILD SOUTH SUNDAY. HIGH PRESSURE WILL EXPAND SOUTH ACROSS
THE AREA NEXT WEEK WITH ITS INFLUENCE WANING LATE NEXT WEEK.
TROPICAL DEPRESSION NUMBER FOUR IN THE SOUTHERN BAHAMAS MAY BECOME A
HURRICANE NEXT WEEK. THIS STORM SHOULD EARN THE NAME CRISTOBAL AS IT
MOVES NORTHWARD THROUGH THE BAHAMAS OVER THE NEXT FEW DAYS.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1030 PM SATURDAY...INLAND CONVECTION DIED A QUICK DEATH
EARLIER THIS EVENING...BUT NEW CONVECTION IS DEVELOPING ALONG THE
LEADING EDGE OF STRONGER NORTHEAST WINDS CURRENTLY IN SOUTHERN NEW
HANOVER AND BRUNSWICK COUNTIES. THIS IS PROBABLY THE SYNOPTIC COLD
FRONT. ADDITIONAL SHOWERS WILL BE POSSIBLE WITH THIS FEATURE AS IT
MOVES SOUTHWESTWARD ACROSS THE AREA OVERNIGHT. A FEW SHOWERS HAVE
ALSO BEEN NOTED ABOUT 50 MILES BEHIND THE BOUNDARY ACROSS NORTHERN
PENDER COUNTY NORTHWESTWARD TOWARD FAYETTEVILLE. SURFACE-BASED OR
ELEVATED INSTABILITY IS GROWING SMALLER HERE AND THE RISK FOR
ADDITIONAL CONVECTIVE ACTIVITY IS LIMITED TO SHOWERS.
OVERALL POPS HAVE BEEN TRIMMED BACK SIGNIFICANTLY FROM EARLIER
FORECASTS...WITH THE POTENTIAL FOR THUNDER LIMITED TO OFFSHORE
LOCATIONS. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS..
MULTIPLE WAVES OF DEEP CONVECTION HAVE DEVELOPED ACROSS THE COASTAL
CAROLINAS IN A MODERATELY UNSTABLE BUT WEAKLY SHEARED AIRMASS. THIS
ACTIVITY IS MOVING SOUTHWARD...DRIVEN BY THE NORTHERLY FLOW AROUND A
BUILDING RIDGE OF MID AND UPPER LEVEL HIGH PRESSURE OVER THE CENTRAL
MISSISSIPPI VALLEY. SURFACE HIGH PRESSURE JUST NORTH OF THE GREAT
LAKES IS EXPANDING DUE TO SUBSIDENCE OUT AHEAD OF THE UPPER RIDGE
AXIS...AND THESE RISING SURFACE PRESSURES ARE HELPING NUDGE A COLD
FRONT SOUTHWARD ACROSS THE AREA. USING THE LEADING EDGE OF THE
STRONGER NORTHEAST WIND SURGE AS A GUIDE...THE FRONT LIES
APPROXIMATELY FROM NEW BERN THROUGH FAYETTEVILLE TO NEAR
ROCKINGHAM...ALTHOUGH PLENTY OF THUNDERSTORM OUTFLOWS IN THE AREA
MAKE THIS ANALYSIS QUITE CONFUSING.
THE CURRENT CONVECTIVE ACTIVITY APPROACHING MYRTLE BEACH AND MARION
IS HAVING A SIGNIFICANT STABILIZING INFLUENCE ON THE AIR AIRMASS...
AND THIS WILL LIKELY BE THE PRIMARY CONVECTIVE EVENT OF THE EVENING.
A FEW SEVERE WEATHER REPORTS WERE RECEIVED EARLIER ACROSS ROBESON
COUNTY WITH THESE SAME STORMS. BEHIND ALL THIS ACTIVITY CLOSER TO
WHAT APPEARS TO BE THE SYNOPTIC FRONT...STRONGER LOW-LEVEL
CONVERGENCE WILL FORCE A LINE OF SHOWERS AND PERHAPS MORE
THUNDERSTORMS TO FORM...ALTHOUGH THE INTENSITY OF THIS CONVECTION
SHOULD BE LESS THAN WHAT WE ARE SEEING CURRENTLY. FORECAST POPS
THROUGH THE EVENING ARE HIGHEST ACROSS COASTAL SOUTH CAROLINA
(70-100 PERCENT) AND LOWEST WEST OF FLORENCE. (30-40 PERCENT)
OVERNIGHT LOWS SHOULD FALL INTO THE LOWER 70S FOR MOST AREAS AS THE
POST-FRONTAL COOL AIRMASS SURGES INTO THE AREA LATER TONIGHT.
TROPICAL DEPRESSION #4 HAS DEVELOPED IN THE SOUTHERN BAHAMAS WITH A
FORECAST TRACK CURRENTLY KEEPING THE STORM OFFSHORE. A PORTION OF
THE PROBABILITY ENVELOPE SURROUNDING THE FORECAST TRACK DOES REACH
THE COAST OF THE CAROLINAS...ALTHOUGH THROUGH DAY 5 (WEDNESDAY
NIGHT) THE PROBABILITIES FOR TROPICAL STORM FORCE WINDS REMAIN 15
PERCENT OR LESS AND DO NOT APPEAR AS ENHANCED WORDING IN OUR PUBLIC
OR MARINE FORECAST TEXT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A COLD FRONT WILL HAVE MOVED THROUGH THE
ENTIRE FORECAST AREA BEFORE 12Z SUN. THE INFLUX OF DRIER AIR WILL
BE STRONGEST AND DEEPEST ACROSS THE NORTHERN ZONES SUN. THE DRY
AIR WILL BE ESPECIALLY PRONOUNCED IN THE MID LEVELS...ABOVE 10-12
KFT. AN ONSHORE FLOW BELOW 10 KFT WILL KEEP THE LOWER LEVELS OF
THE COLUMN MORE MOIST. A SHORTWAVE PUSHING DOWN THE SOUTHEAST
COAST MAY TOUCH OFF SOME SHALLOWER CONVECTION. WILL CARRY A SLIGHT
CHANCE TO SMALL CHANCE OF SHOWERS AND THUNDERSTORMS ON SUNDAY WITH
THE RISK DECREASING FROM NORTH TO SOUTH AS THE DAY PROGRESSES.
PRECIPITABLE WATER VALUES WILL BE DROPPING BELOW THREE-QUARTERS OF
AN INCH SUN NIGHT AS MUCH DRIER AIR OVERWHELMS THE COLUMN DOWN TO
THE SURFACE. THUS...WILL NOT CARRY ANY POPS BEYOND NIGHTFALL. A DEEP
AND TIGHTENING NE FLOW WILL BE PRESENT MON AND MON NIGHT AS A WEDGE
OF HIGH PRESSURE BUILDS STRONGLY ACROSS WESTERN NORTH CAROLINA AND
THE UPSTATE OF SOUTH CAROLINA. AT THE SAME TIME...DEVELOPING
TROPICAL LOW PRESSURE ACROSS THE BAHAMAS WILL RESULT IN A TIGHTENING
PRESSURE GRADIENT. AN INVERTED TROUGH MAY BEGIN TO DEVELOP DURING
THIS TIME AND IF IT COMES CLOSE ENOUGH TO THE COAST...A FEW SHOWERS
MAY IMPINGE ONTO THE COAST. AT THIS TIME...WILL KEEP ANY MENTION OF
CONVECTION OFFSHORE...BUT SHOW SOME INCREASING CLOUD COVER AS
THE COLUMN DOES BEGIN TO MOISTEN BACK UP IN THE LOWER LEVELS.
HIGH TEMPS WILL BE MAINLY NEAR TO A FEW DEGREES BELOW NORMAL THIS
PERIOD AS WE WILL BE UNDER A NE FLOW REGIME. HIGHS BOTH DAYS WILL BE
IN THE MID AND UPPER 80S. DEWPOINTS WILL ALSO BE CONSIDERABLY LOWER
THAN RECENT DAYS AND SO FOR MOST...IT WILL BE MUCH MORE PLEASANT.
LOWS WILL BE BELOW NORMAL AND MAINLY IN THE MID TO UPPER 60S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...THE EXTENDED CONTINUES TO BE DOMINATED BY
MID LEVEL HIGH PRESSURE MOVING FROM THE MISSISSIPPI VALLEY TO THE
SOUTHEAST BY NEXT WEEKEND. AT THE SURFACE HIGH PRESSURE WILL BE THE
MAIN FEATURE FOR TUESDAY AND WEDNESDAY WITH A COOL NORTHEAST FLOW.
THE HIGH BECOMES MORE DIFFUSE THURSDAY...A LITTLE EARLIER THAN
PREVIOUS GUIDANCE. THE SYSTEM FOR LATE IN THE WEEK LOOKS
CONSIDERABLY WEAKER AS WELL. CHANGES TO THE FORECAST THIS AFTERNOON
ARE MINIMAL. I DID INCREASE POPS FOR FRIDAY AND SATURDAY TO MATCH
OTHER OFFICES BETTER BUT THE VALUES ARE STILL LOWER THAN THIS TIME
YESTERDAY. THE TEMPERATURE FORECAST HAS INCREASED ESPECIALLY FOR
THURSDAY AND FRIDAY WITH READINGS NEARING OR EVEN EXCEEDING
CLIMATOLOGY SLIGHTLY FOR THESE PERIODS INCLUDING SATURDAY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION IS STILL ONGOING ACROSS THE CENTRAL PART OF
OUR CWA THIS EVENING...MOVING SOUTH TOWARD THE COAST. HAVE INCLUDED
TEMPO MVFR/TSRA FOR KCRE/KMYR JUST AFTER 00Z AS THESE SITES WILL SEE
STORMS MOVE OVERHEAD SHORTLY. ELSEWHERE...VCSH SHOULD COVER IT THRU
TONIGHT AS HRRR SHOWS SHOWER ACTIVITY WINDING DOWN BY MIDNIGHT.
THE COLD FRONT WILL FINALLY PUSH THROUGH OUR CWA LATE TONIGHT
ACCOMPANIED BY INCREASING NORTHEAST WINDS. FOG WILL NOT BE AN ISSUE
GIVEN THE 5-8 KT SFC WINDS...BUT MVFR CIGS ARE EXPECTED AT ALL TERMS
AFTER 06Z SUN. TEMPO IFR STRATUS CANNOT BE RULED OUT AT KFLO/KLBT
AROUND DAYBREAK...BUT WILL KEEP PREVAILING MVFR ATTM UNTIL IFR
CONFIDENCE INCREASES. MVFR CIGS COULD LINGER THRU THE MORNING HOURS
AS NORTHEAST WINDS STRENGTHEN TO 10-15 KT WITH HIGHER GUSTS. VFR
SHOULD PREVAIL DURING THE AFTERNOON HOURS AS SFC HIGH PRESSURE
BUILDS SOUTHWARD.
EXTENDED OUTLOOK...EXPECT VFR TO PREVAIL THROUGH WED WITH A RIDGE OF
HIGH PRESSURE OVER THE EAST COAST. CHANCE OF SHRA THU.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM SATURDAY...THE SURGE LINE/COLD FRONT IS APPARENTLY
ACCELERATING SOUTHWESTWARD AND APPEARS TO BE LOCATED NEAR CAROLINA
BEACH AT THE CURRENT TIME. RECENT OBSERVATIONS FROM WRIGHTSVILLE
BEACH INDICATE GUSTS AS HIGH AS 20 KNOTS...WITH 19 KNOT GUSTS AT THE
BUOY 5 MILES TO THE SOUTHEAST. THESE WINDS WILL SPREAD SOUTHWESTWARD
DOWN THE COAST PRETTY MUCH AS EARLIER PREDICTED. PREVIOUS DISCUSSION
FROM 730 PM FOLLOWS...
A COLD FRONT WILL BE MOVING SOUTHWARD ACROSS THE COASTAL WATERS
TONIGHT...ALTHOUGH THE EXACT POSITION OF THE FRONT IS QUITE
DIFFICULT TO DEFINE GIVEN ALL THE THUNDERSTORM OUTFLOWS IN THE AREA.
ASSUMING THE LEADING EDGE OF STRONGER NORTHEAST WINDS IN NORTH
CAROLINA IS THE ACTUAL FRONT...IT CURRENTLY LIES FROM NEW BERN TO
NEAR FAYETTEVILLE AND IS DROPPING SOUTHWARD AT AROUND 12 KNOTS.
AS THIS WIND SHIFT/FRONT ARRIVES LATER TONIGHT...LIGHT EASTERLY
WINDS WILL SHIFT TO THE NORTHEAST AND INCREASE TO AROUND 15 KNOTS.
THIS WILL BUILD SEAS FRONT THE CURRENTLY-OBSERVED 1.5-2 FEET UP TO
3-4 FEET BY DAYBREAK SUNDAY.
THUNDERSTORM ACTIVITY HAS BEEN RATHER WIDESPREAD THIS AFTERNOON AND
EARLY THIS EVENING. ANOTHER CONVECTIVE CLUSTER LOOKS TO TARGET THE
MYRTLE BEACH AREA IN THE NEXT HOUR...WITH ADDITIONAL SHOWERS AND
POSSIBLE THUNDERSTORMS ACCOMPANYING THE WIND SHIFT/FRONT LATER
TONIGHT. MONITOR OUR LATEST MARINE WEATHER STATEMENTS OR WARNINGS
WHICH WILL BE ISSUED FOR PARTICULARLY DANGEROUS STORMS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...THE GRADIENT WILL BE TIGHTENING UP DURING
THIS PERIOD. A NE SURGE SUNDAY WILL BECOME FORTIFIED BY A TIGHTENING
PRESSURE GRADIENT BETWEEN HIGH PRESSURE ACROSS THE NORTHEAST U.S.
AND A DEVELOPING TROPICAL LOW ACROSS THE BAHAMAS. THIS WILL SERVE TO
NOT ONLY PROLONG THE NE FLOW...BUT TO INCREASE ITS MAGNITUDE.
THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED BEGINNING SUNDAY
MORNING. WINDS WILL COMMONLY BE SUSTAINED AT 20 TO 25 KT. A NE FETCH
WILL BUILD SEAS TO 4 TO 7 FT AND 8 FT OR HIGHER BEYOND 20 NM.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...THE MARINE COMMUNITY CAN EXPECT A
NORTHEAST FLOW TUESDAY ON THE ORDER OF 15-20 KNOTS. THIS FLOW WILL
DIMINISH QUITE A BIT WEDNESDAY ESSENTIALLY BECOMING VARIABLE BY
DAYS END. FOR THURSDAY A VERY LIGHT FLOW CAN BE EXPECTED AS THE
WATERS ARE IN BETWEEN RETREATING HIGH PRESSURE TO THE NORTH AND
THE BUILDING BERMUDA RIDGE. WILL LIKELY SEE WINDS MORE INFLUENCED
BY THE SEA BREEZE THIS DAY. SIGNIFICANT SEAS CONTINUE TO BE
PROBLEMATIC DEPENDING ON THE TRACK AND INTENSITY OF AL96. FORECAST
SHOWS 2-6 FEET TUESDAY WITH AN INCREASE MOSTLY IN THE OUTER WATERS
WEDNESDAY AND THURSDAY DUE ALMOST EXCLUSIVELY TO INCREASED SWELL
COMPONENT FROM THE AFOREMENTIONED SYSTEM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 8 PM EDT MONDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
817 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH THROUGH NORTH CAROLINA
TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION WITH COOLER AND
DRIER CONDITIONS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 817 PM SATURDAY...
MUCH MORE STABLE AIR HAS BEEN ADVECTING INTO CENTRAL NORTH CAROLINA
FROM THE NORTHEAST SINCE LATE AFTERNOON. THE PROCESS WAS SLOW TO
START... BUT HAS REALLY PROGRESSED IN RECENT HOURS. THIS MAY BE BEST
ILLUSTRATED BY THE 800 PM TEMPERATURES WHICH RANGED FROM THE LOWER
70S NE INTO THE LOWER 80S SW. THIS COOLING AND STABILIZING PROCESS
SHOULD CONTINUE TO ACCELERATE WITH NIGHTFALL. ONLY SPOTTY LIGHT
SHOWERS WERE LINGERING OVER THE REGION WITH THE EXCEPTION OF THE
CLUSTER OF SHOWERS MOVING TOWARD STOKES/SURRY COUNTIES OF THE
FOOTHILLS. WE WILL UPDATE THE LATEST FORECAST TO INDICATE A CHANCE
OF SHOWERS IN THE NW... WITH SLIGHT CHANCES ELSEWHERE THROUGH 200
AM. OTHERWISE... THE NE FLOW WILL ALSO ADVECT MOISTURE IN FROM THE
ATLANTIC WHICH WILL CONTINUE TO TRANSLATE INTO A STRATUS LAYER
YIELDING MOSTLY CLOUDY SKIES OVERNIGHT. LOWS 67-72 NE TO S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT /...
AS OF 305 PM SATURDAY...
THE COLD FRONT WILL HAVE PUSHED WELL SOUTH OF THE REGION BY SUNDAY
MORNING WITH COOL HIGH PRESSURE BUILDING INTO CENTRAL NC IN ITS
WAKE. WHILE MUCH DRIER AIR WILL MOVE INTO THE REGION AT MID AND
UPPER LEVELS...SHALLOW LOW LEVEL MOISTURE WILL LINGER ESPECIALLY IN
AN ARC FROM THE WESTERN PIEDMONT INTO THE SOUTHERN PIEDMONT AND EAST
TOWARD THE SANDHILLS AND COASTAL PLAIN. A FEW SHOWERS MAY DEVELOP IN
THIS REGION...ESPECIALLY EARLY ON SUNDAY...BUT LIMITED MOISTURE AND
A CAPPING INVERSION SHOULD PRECLUDE DEEP CONVECTION AND LIMIT
PRECIPITATION COVERAGE. A FAIR AMOUNT OF STRATO CUMULUS IS EXPECTED
THOUGH. WITH A COOLER AIR MASS AND BELOW NORMAL THICKNESS VALUES...
HIGHS ON SUNDAY WILL ONLY RANGE IN THE LOWER TO MID 80S. LOWS SUNDAY
NIGHT WILL RANGE IN THE LOWER 60S. -BLAES
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
FOR MONDAY THROUGH MID-WEDNESDAY...LOOK FOR FAIR WEATHER WITH NEAR-
TO SLIGHTLY-BELOW NORMAL TEMPS (HIGHS IN THE LOW-MID 80S AND LOWS IN
THE LOW 60S) AS HIGH PRESSURE BUILDS IN TO THE CAROLINAS FROM THE
NORTH EARLY IN THE WEEK AND REMAINS OVER OUR AREA THROUGH MID-WEEK.
FORECAST SOUNDINGS SUGGEST PWAT WILL RANGE FROM 0.5-1.0 INCHES
DURING THIS TIME...WHICH IS WELL BELOW THE 1.35 INCH NORM FOR LATE
AUGUST.
A LARGE DEGREE OF UNCERTAINTY EXISTS FOR THE SECOND HALF OF THE
WEEK...AS THIS PART OF THE FORECAST IS LARGELY DEPENDENT ON WHAT
HAPPENS WITH INVEST 96L. TRACK MODELS HAVE BEEN QUITE SCATTERED AND
LITTLE AGREEMENT AMONG THE GEFS/NAEFS MEMBERS. HOWEVER...ITS WORTH
NOTING THAT THE TREND IN THE OPERATIONAL GFS HAS BEEN DEVELOPMENT
AND SLOW NORTHWARD MOVEMENT E OF FL DURING THE FIRST HALF OF THE
WEEK...THEN MOVING NNE ALONG BUT REMAINING OFF THE CAROLINA COAST
LATE IN THE WEEK. THE LATEST ECMWF IS SIMILAR WITH THE EVOLUTION OF
THIS SYSTEM...BUT IS FASTER AND ITS TRACK REMAINS FURTHER OFF THE
COAST...SHOWING THE LOW MOVING NE AWAY FROM THE EAST COAST ON
THURSDAY. ESSENTIALLY BOTH OF THESE SOLUTIONS WOULD KEEP CENTRAL NC
FAR ENOUGH WEST OF THE SYSTEM SUCH THAT OUR AREA WOULD REMAIN IN
FAIR WEATHER DURING THE SECOND HALF OF THE WEEK. TAKING THAT SYSTEM
OUT OF THE PICTURE...OUR NEXT CHANCE FOR WET WEATHER WOULD COME
DURING THE WEEKEND ASSOCIATED WITH EITHER THE NEXT TROUGH IN THE
WESTERLIES (PER GFS) OR INCREASING MOISTURE IN THE RETURN FLOW
AROUND THE RIDGE (PER THE ECWMF). IN SUMMARY...LOTS OF UNCERTAINTY
FOR THE SECOND HALF OF THE LONG TERM...SO WILL STICK CLOSE TO CLIMO
FOR TEMPS AND PERHAPS A LITTLE LOWER THAN CLIMO FOR POPS DURING THIS
TIME.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 800 PM SATURDAY...
THE AIR MASS OVER CENTRAL NORTH CAROLINA WAS GRADUALLY BECOMING MORE
STABLE ESPECIALLY OVER A DEEP LAYER...BUT EVENING RADAR TRENDS WERE
CONSISTENT WITH MODEL SOUNDING DEPICTIONS OF LOW-LEVEL MOISTURE AND
INSTABILITY WITH WIDELY SCATTERED SHOWERS AHEAD OF A COLD FRONT AND
MID-LEVEL RELATIVE JET MAXIMUM. ISOLATED THUNDER IS STILL POSSIBLE
THIS EVENING MAINLY TOWARD KINT. CHALLENGE FOR THE OVERNIGHT HOURS
INTO SUNDAY MORNING IS THE DEGREE OF LOW CLOUDINESS. THE STATISTICAL
GUIDANCE IS HIGH ON THE PROBABILITY OF IFR CLOUDS THROUGHOUT CENTRAL
NORTH CAROLINA FOR A TIME OVERNIGHT ESPECIALLY BETWEEN ABOUT 07Z AND
12Z...WHILE THE SREF MODEL PROBABILITIES OF LOW CLOUDS ARE
NOTICEABLY HIGHER TOWARD THE TRIAD...MODEST TOWARD KRDU...AND LOWEST
TOWARD KFAY AND KRWI. TAFS TEND TO MIRROR MORE THE SREF TREND...
LONGEST WITH IFR CONDITIONS OVERNIGHT TOWARD KINT AND KGSO...SHORTER
IN TIME AT KRDU...AND CURRENTLY NOTED SCATTERED LOW CLOUDS AND MVFR
CONDITIONS PREVAILING AT KFAY AND KRWI. THERE IS CERTAINLY THE
CHANCE THAT KFAY AND KRWI COULD HAVE A PERIOD OF LOW CLOUDS BUT EVEN
THE LATEST HRRR WRF MODEL LEANS TOWARD THE SREF. ON SUNDAY...WITH
MIXING CEILINGS SHOULD GRADUALLY RISE TO AT LEAST LOW VFR EVEN IN
THE TRIAD BY 18Z...WITH A NORTHEAST WIND SHOWING GUSTS IN THE TEENS
KTS.
BEYOND THE 00Z VALID TAF PERIOD...VFR CONDITIONS SHOULD BE
PREVALENT. SOME GUIDANCE SUGGESTS THE POTENTIAL FOR MVFR CONDITIONS
MAINLY TOWARD THE COASTAL PLAIN OVERNIGHT MONDAY INTO TUESDAY. THE
LOW-LEVEL FLOW SHOULD BE PERSISTENTLY NORTHEAST...POSSIBLY STARTING
TO VEER WEDNESDAY INTO THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES/DJF
NEAR TERM...PWB
SHORT TERM...BLAES
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
802 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH THROUGH NORTH CAROLINA
TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION WITH COOLER AND
DRIER CONDITIONS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 PM SATURDAY...
LATEST SURFACE ANALYSIS CONTINUES TO REVEAL A COMPLEX SURFACE
PATTERN WITH THE BACK DOOR COLD FRONT NOW EXTENDING FROM WESTERN
VIRGINIA EAST NEAR THE VA/NC BORDER AND THEN SOUTHEAST TOWARD THE
MID CAROLINA COAST. A SURFACE TROUGH ALSO EXTENDS NORTH TO
SOUTHEAST ACROSS THE NC/SC COASTAL REGION SEPARATING AN
INCREASINGLY DEEP EASTERLY FLOW AS NOTED BY THE HMT-SEPS WIND
PROFILER NEAR NEW BERN. A WEAK SURFACE LOW WAS ALSO ANALYZED JUST
NORTH OF KCHS WITH A STEAMY 903/79 OBSERVED AT KGGE. A NORTHWEST
FLOW ALOFT DOMINATES THE SYNOPTIC PATTERN WITH SEVERAL WAVES NOTED
IN THE FLOW ALONG WITH A STRENGTHENING NORTHERN STREAM JET POISED TO
DROP INTO THE MID ATLANTIC...NOTE THE 105KT JET AT 200 HPA AT KIAD
THIS MORNING. MORNING RAOBS ACROSS THE CAROLINAS DEPICT A VERY MOIST
ATMOSPHERE PRECIPITABLE WATER VALUES OF 120-135% OF NORMAL AT
KGSO/KMHX RESPECTIVELY.
NOT SURPRISED TO SHEE SHOWERS AND THUNDERSTORMS SLOWLY EXPANDING
THIS AFTERNOON GIVEN THE ENHANCED FLOW ALOFT...AT LEAST ONE
DISTURBANCE ALOFT OVER WESTERN VA AND MULTIPLE MECHANISMS FOR LOW
LEVEL CONVERGENCE. CURRENT RADAR TRENDS DEPICT ONE AREA OF
CONVECTION ACROSS THE NORTHERN PIEDMONT OF NC AND SOUTHERN VA IN
PROXIMITY TO THE SURFACE FRONT AND A DISTURBANCE IN THE NW FLOW
ALOFT. OTHER CONVECTION ACROSS THE COASTAL PLAIN AND COASTAL REGION
IS DRIVEN IN A MORE UNSTABLE AIR MASS NEAR THE SURFACE TROUGH. USED
A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO GENERATE THE HOURLY
POP/QPF/WX GRIDS FOR THIS AFTERNOON AND EVENING. WHILE CONVECTIVE
COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...MLCAPE VALUES WILL
GENERALLY RANGE LESS THAN 1000 J/KG EXCEPT ACROSS THE SOUTHERN
COASTAL PLAIN AND SANDHILLS WHERE VALUES MAY EXCEED 1500 J/KG WHICH
SHOULD MINIMIZE CONVECTIVE INTENSITY IN MOST LOCATIONS. THE BEST
FLOW ALOFT SHOULD REMAIN IN THE VA/MD/DE REGION WITH BULK SHEAR
VALUES IN OUR CWA CLIMBING TO AROUND 25KTS. THE BIGGER THREAT WILL
LIKELY BE ASSOCIATED WITH LOCALLY HEAVY RAIN WITH CELLS ORIENTED IN
THE NW FLOW THAT REPEATEDLY MOVE OVER A GIVEN AREA.
THE CONVECTIVE CONVERGE WILL INCREASE A BIT DURING THE NEXT SEVERAL
HOURS WITH THE FOCUS GRADUALLY SHIFTING SOUTH INTO THE EVENING
ALTHOUGH ISOLATED SHOWERS OR THUNDERSTORMS ARE POSSIBLE AT ANY TIME.
A PROMINENT AREA OF CONVECTION UPSTREAM ACROSS IL/IN IS PROGGED TO
WEAKEN AS IT MOVES SOUTHEAST AND SHOULD NOT IMPACT CENTRAL NC. LOW
TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 60S NORTHEAST TO
LOWER 70S SOUTHWEST. -BLAES
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT /...
AS OF 305 PM SATURDAY...
THE COLD FRONT WILL HAVE PUSHED WELL SOUTH OF THE REGION BY SUNDAY
MORNING WITH COOL HIGH PRESSURE BUILDING INTO CENTRAL NC IN ITS
WAKE. WHILE MUCH DRIER AIR WILL MOVE INTO THE REGION AT MID AND
UPPER LEVELS...SHALLOW LOW LEVEL MOISTURE WILL LINGER ESPECIALLY IN
AN ARC FROM THE WESTERN PIEDMONT INTO THE SOUTHERN PIEDMONT AND EAST
TOWARD THE SANDHILLS AND COASTAL PLAIN. A FEW SHOWERS MAY DEVELOP IN
THIS REGION...ESPECIALLY EARLY ON SUNDAY...BUT LIMITED MOISTURE AND
A CAPPING INVERSION SHOULD PRECLUDE DEEP CONVECTION AND LIMIT
PRECIPITATION COVERAGE. A FAIR AMOUNT OF STRATO CUMULUS IS EXPECTED
THOUGH. WITH A COOLER AIR MASS AND BELOW NORMAL THICKNESS VALUES...
HIGHS ON SUNDAY WILL ONLY RANGE IN THE LOWER TO MID 80S. LOWS SUNDAY
NIGHT WILL RANGE IN THE LOWER 60S. -BLAES
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
FOR MONDAY THROUGH MID-WEDNESDAY...LOOK FOR FAIR WEATHER WITH NEAR-
TO SLIGHTLY-BELOW NORMAL TEMPS (HIGHS IN THE LOW-MID 80S AND LOWS IN
THE LOW 60S) AS HIGH PRESSURE BUILDS IN TO THE CAROLINAS FROM THE
NORTH EARLY IN THE WEEK AND REMAINS OVER OUR AREA THROUGH MID-WEEK.
FORECAST SOUNDINGS SUGGEST PWAT WILL RANGE FROM 0.5-1.0 INCHES
DURING THIS TIME...WHICH IS WELL BELOW THE 1.35 INCH NORM FOR LATE
AUGUST.
A LARGE DEGREE OF UNCERTAINTY EXISTS FOR THE SECOND HALF OF THE
WEEK...AS THIS PART OF THE FORECAST IS LARGELY DEPENDENT ON WHAT
HAPPENS WITH INVEST 96L. TRACK MODELS HAVE BEEN QUITE SCATTERED AND
LITTLE AGREEMENT AMONG THE GEFS/NAEFS MEMBERS. HOWEVER...ITS WORTH
NOTING THAT THE TREND IN THE OPERATIONAL GFS HAS BEEN DEVELOPMENT
AND SLOW NORTHWARD MOVEMENT E OF FL DURING THE FIRST HALF OF THE
WEEK...THEN MOVING NNE ALONG BUT REMAINING OFF THE CAROLINA COAST
LATE IN THE WEEK. THE LATEST ECMWF IS SIMILAR WITH THE EVOLUTION OF
THIS SYSTEM...BUT IS FASTER AND ITS TRACK REMAINS FURTHER OFF THE
COAST...SHOWING THE LOW MOVING NE AWAY FROM THE EAST COAST ON
THURSDAY. ESSENTIALLY BOTH OF THESE SOLUTIONS WOULD KEEP CENTRAL NC
FAR ENOUGH WEST OF THE SYSTEM SUCH THAT OUR AREA WOULD REMAIN IN
FAIR WEATHER DURING THE SECOND HALF OF THE WEEK. TAKING THAT SYSTEM
OUT OF THE PICTURE...OUR NEXT CHANCE FOR WET WEATHER WOULD COME
DURING THE WEEKEND ASSOCIATED WITH EITHER THE NEXT TROUGH IN THE
WESTERLIES (PER GFS) OR INCREASING MOISTURE IN THE RETURN FLOW
AROUND THE RIDGE (PER THE ECWMF). IN SUMMARY...LOTS OF UNCERTAINTY
FOR THE SECOND HALF OF THE LONG TERM...SO WILL STICK CLOSE TO CLIMO
FOR TEMPS AND PERHAPS A LITTLE LOWER THAN CLIMO FOR POPS DURING THIS
TIME.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 800 PM SATURDAY...
THE AIR MASS OVER CENTRAL NORTH CAROLINA WAS GRADUALLY BECOMING MORE
STABLE ESPECIALLY OVER A DEEP LAYER...BUT EVENING RADAR TRENDS WERE
CONSISTENT WITH MODEL SOUNDING DEPICTIONS OF LOW-LEVEL MOISTURE AND
INSTABILITY WITH WIDELY SCATTERED SHOWERS AHEAD OF A COLD FRONT AND
MID-LEVEL RELATIVE JET MAXIMUM. ISOLATED THUNDER IS STILL POSSIBLE
THIS EVENING MAINLY TOWARD KINT. CHALLENGE FOR THE OVERNIGHT HOURS
INTO SUNDAY MORNING IS THE DEGREE OF LOW CLOUDINESS. THE STATISTICAL
GUIDANCE IS HIGH ON THE PROBABILITY OF IFR CLOUDS THROUGHOUT CENTRAL
NORTH CAROLINA FOR A TIME OVERNIGHT ESPECIALLY BETWEEN ABOUT 07Z AND
12Z...WHILE THE SREF MODEL PROBABILITIES OF LOW CLOUDS ARE
NOTICEABLY HIGHER TOWARD THE TRIAD...MODEST TOWARD KRDU...AND LOWEST
TOWARD KFAY AND KRWI. TAFS TEND TO MIRROR MORE THE SREF TREND...
LONGEST WITH IFR CONDITIONS OVERNIGHT TOWARD KINT AND KGSO...SHORTER
IN TIME AT KRDU...AND CURRENTLY NOTED SCATTERED LOW CLOUDS AND MVFR
CONDITIONS PREVAILING AT KFAY AND KRWI. THERE IS CERTAINLY THE
CHANCE THAT KFAY AND KRWI COULD HAVE A PERIOD OF LOW CLOUDS BUT EVEN
THE LATEST HRRR WRF MODEL LEANS TOWARD THE SREF. ON SUNDAY...WITH
MIXING CEILINGS SHOULD GRADUALLY RISE TO AT LEAST LOW VFR EVEN IN
THE TRIAD BY 18Z...WITH A NORTHEAST WIND SHOWING GUSTS IN THE TEENS
KTS.
BEYOND THE 00Z VALID TAF PERIOD...VFR CONDITIONS SHOULD BE
PREVALENT. SOME GUIDANCE SUGGESTS THE POTENTIAL FOR MVFR CONDITIONS
MAINLY TOWARD THE COASTAL PLAIN OVERNIGHT MONDAY INTO TUESDAY. THE
LOW-LEVEL FLOW SHOULD BE PERSISTENTLY NORTHEAST...POSSIBLY STARTING
TO VEER WEDNESDAY INTO THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES/DJF
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
740 PM EDT SAT AUG 23 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TONIGHT...ACCOMPANIED
BY SHOWERS AND THUNDERSTORMS. PROGRESSIVELY DRIER AND COOLER AIR
WILL BUILD SOUTH SUNDAY. HIGH PRESSURE WILL EXPAND SOUTH ACROSS THE
AREA NEXT WEEK WITH ITS INFLUENCE WANING LATE NEXT WEEK. TROPICAL
DEPRESSION NUMBER FOUR IN THE SOUTHERN BAHAMAS MAY BECOME A
HURRICANE NEXT WEEK. THIS STORM SHOULD EARN THE NAME CRISTOBAL AS IT
MOVES NORTHWARD THROUGH THE BAHAMAS OVER THE NEXT FEW DAYS.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 730 PM SATURDAY...MULTIPLE WAVES OF DEEP CONVECTION HAVE
DEVELOPED ACROSS THE COASTAL CAROLINAS IN A MODERATELY UNSTABLE BUT
WEAKLY SHEARED AIRMASS. THIS ACTIVITY IS MOVING SOUTHWARD...DRIVEN
BY THE NORTHERLY FLOW AROUND A BUILDING RIDGE OF MID AND UPPER LEVEL
HIGH PRESSURE OVER THE CENTRAL MISSISSIPPI VALLEY. SURFACE HIGH
PRESSURE JUST NORTH OF THE GREAT LAKES IS EXPANDING DUE TO
SUBSIDENCE OUT AHEAD OF THE UPPER RIDGE AXIS...AND THESE RISING
SURFACE PRESSURES ARE HELPING NUDGE A COLD FRONT SOUTHWARD ACROSS
THE AREA. USING THE LEADING EDGE OF THE STRONGER NORTHEAST WIND
SURGE AS A GUIDE...THE FRONT LIES APPROXIMATELY FROM NEW BERN
THROUGH FAYETTEVILLE TO NEAR ROCKINGHAM...ALTHOUGH PLENTY OF
THUNDERSTORM OUTFLOWS IN THE AREA MAKE THIS ANALYSIS QUITE
CONFUSING.
THE CURRENT CONVECTIVE ACTIVITY APPROACHING MYRTLE BEACH AND MARION
IS HAVING A SIGNIFICANT STABILIZING INFLUENCE ON THE AIR AIRMASS...
AND THIS WILL LIKELY BE THE PRIMARY CONVECTIVE EVENT OF THE EVENING.
A FEW SEVERE WEATHER REPORTS WERE RECEIVED EARLIER ACROSS ROBESON
COUNTY WITH THESE SAME STORMS. BEHIND ALL THIS ACTIVITY CLOSER TO
WHAT APPEARS TO BE THE SYNOPTIC FRONT...STRONGER LOW-LEVEL
CONVERGENCE WILL FORCE A LINE OF SHOWERS AND PERHAPS MORE
THUNDERSTORMS TO FORM...ALTHOUGH THE INTENSITY OF THIS CONVECTION
SHOULD BE LESS THAN WHAT WE ARE SEEING CURRENTLY. FORECAST POPS
THROUGH THE EVENING ARE HIGHEST ACROSS COASTAL SOUTH CAROLINA
(70-100 PERCENT) AND LOWEST WEST OF FLORENCE. (30-40 PERCENT)
OVERNIGHT LOWS SHOULD FALL INTO THE LOWER 70S FOR MOST AREAS AS THE
POST-FRONTAL COOL AIRMASS SURGES INTO THE AREA LATER TONIGHT.
TROPICAL DEPRESSION #4 HAS DEVELOPED IN THE SOUTHERN BAHAMAS WITH A
FORECAST TRACK CURRENTLY KEEPING THE STORM OFFSHORE. A PORTION OF
THE PROBABILITY ENVELOPE SURROUNDING THE FORECAST TRACK DOES REACH
THE COAST OF THE CAROLINAS...ALTHOUGH THROUGH DAY 5 (WEDNESDAY
NIGHT) THE PROBABILITIES FOR TROPICAL STORM FORCE WINDS REMAIN 15
PERCENT OR LESS AND DO NOT APPEAR AS ENHANCED WORDING IN OUR PUBLIC
OR MARINE FORECAST TEXT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A COLD FRONT WILL HAVE MOVED THROUGH THE
ENTIRE FORECAST AREA BEFORE 12Z SUN. THE INFLUX OF DRIER AIR WILL
BE STRONGEST AND DEEPEST ACROSS THE NORTHERN ZONES SUN. THE DRY
AIR WILL BE ESPECIALLY PRONOUNCED IN THE MID LEVELS...ABOVE 10-12
KFT. AN ONSHORE FLOW BELOW 10 KFT WILL KEEP THE LOWER LEVELS OF
THE COLUMN MORE MOIST. A SHORTWAVE PUSHING DOWN THE SOUTHEAST
COAST MAY TOUCH OFF SOME SHALLOWER CONVECTION. WILL CARRY A SLIGHT
CHANCE TO SMALL CHANCE OF SHOWERS AND THUNDERSTORMS ON SUNDAY WITH
THE RISK DECREASING FROM NORTH TO SOUTH AS THE DAY PROGRESSES.
PRECIPITABLE WATER VALUES WILL BE DROPPING BELOW THREE-QUARTERS OF
AN INCH SUN NIGHT AS MUCH DRIER AIR OVERWHELMS THE COLUMN DOWN TO
THE SURFACE. THUS...WILL NOT CARRY ANY POPS BEYOND NIGHTFALL. A DEEP
AND TIGHTENING NE FLOW WILL BE PRESENT MON AND MON NIGHT AS A WEDGE
OF HIGH PRESSURE BUILDS STRONGLY ACROSS WESTERN NORTH CAROLINA AND
THE UPSTATE OF SOUTH CAROLINA. AT THE SAME TIME...DEVELOPING
TROPICAL LOW PRESSURE ACROSS THE BAHAMAS WILL RESULT IN A TIGHTENING
PRESSURE GRADIENT. AN INVERTED TROUGH MAY BEGIN TO DEVELOP DURING
THIS TIME AND IF IT COMES CLOSE ENOUGH TO THE COAST...A FEW SHOWERS
MAY IMPINGE ONTO THE COAST. AT THIS TIME...WILL KEEP ANY MENTION OF
CONVECTION OFFSHORE...BUT SHOW SOME INCREASING CLOUD COVER AS
THE COLUMN DOES BEGIN TO MOISTEN BACK UP IN THE LOWER LEVELS.
HIGH TEMPS WILL BE MAINLY NEAR TO A FEW DEGREES BELOW NORMAL THIS
PERIOD AS WE WILL BE UNDER A NE FLOW REGIME. HIGHS BOTH DAYS WILL BE
IN THE MID AND UPPER 80S. DEWPOINTS WILL ALSO BE CONSIDERABLY LOWER
THAN RECENT DAYS AND SO FOR MOST...IT WILL BE MUCH MORE PLEASANT.
LOWS WILL BE BELOW NORMAL AND MAINLY IN THE MID TO UPPER 60S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...THE EXTENDED CONTINUES TO BE DOMINATED BY
MID LEVEL HIGH PRESSURE MOVING FROM THE MISSISSIPPI VALLEY TO THE
SOUTHEAST BY NEXT WEEKEND. AT THE SURFACE HIGH PRESSURE WILL BE THE
MAIN FEATURE FOR TUESDAY AND WEDNESDAY WITH A COOL NORTHEAST FLOW.
THE HIGH BECOMES MORE DIFFUSE THURSDAY...A LITTLE EARLIER THAN
PREVIOUS GUIDANCE. THE SYSTEM FOR LATE IN THE WEEK LOOKS
CONSIDERABLY WEAKER AS WELL. CHANGES TO THE FORECAST THIS AFTERNOON
ARE MINIMAL. I DID INCREASE POPS FOR FRIDAY AND SATURDAY TO MATCH
OTHER OFFICES BETTER BUT THE VALUES ARE STILL LOWER THAN THIS TIME
YESTERDAY. THE TEMPERATURE FORECAST HAS INCREASED ESPECIALLY FOR
THURSDAY AND FRIDAY WITH READINGS NEARING OR EVEN EXCEEDING
CLIMATOLOGY SLIGHTLY FOR THESE PERIODS INCLUDING SATURDAY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION IS STILL ONGOING ACROSS THE CENTRAL PART OF
OUR CWA THIS EVENING...MOVING SOUTH TOWARD THE COAST. HAVE INCLUDED
TEMPO MVFR/TSRA FOR KCRE/KMYR JUST AFTER 00Z AS THESE SITES WILL SEE
STORMS MOVE OVERHEAD SHORTLY. ELSEWHERE...VCSH SHOULD COVER IT THRU
TONIGHT AS HRRR SHOWS SHOWER ACTIVITY WINDING DOWN BY MIDNIGHT.
THE COLD FRONT WILL FINALLY PUSH THROUGH OUR CWA LATE TONIGHT
ACCOMPANIED BY INCREASING NORTHEAST WINDS. FOG WILL NOT BE AN ISSUE
GIVEN THE 5-8 KT SFC WINDS...BUT MVFR CIGS ARE EXPECTED AT ALL TERMS
AFTER 06Z SUN. TEMPO IFR STRATUS CANNOT BE RULED OUT AT KFLO/KLBT
AROUND DAYBREAK...BUT WILL KEEP PREVAILING MVFR ATTM UNTIL IFR
CONFIDENCE INCREASES. MVFR CIGS COULD LINGER THRU THE MORNING HOURS
AS NORTHEAST WINDS STRENGTHEN TO 10-15 KT WITH HIGHER GUSTS. VFR
SHOULD PREVAIL DURING THE AFTERNOON HOURS AS SFC HIGH PRESSURE
BUILDS SOUTHWARD.
EXTENDED OUTLOOK...EXPECT VFR TO PREVAIL THROUGH WED WITH A RIDGE OF
HIGH PRESSURE OVER THE EAST COAST. CHANCE OF SHRA THU.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SATURDAY...A COLD FRONT WILL BE MOVING SOUTHWARD ACROSS
THE COASTAL WATERS TONIGHT...ALTHOUGH THE EXACT POSITION OF THE
FRONT IS QUITE DIFFICULT TO DEFINE GIVEN ALL THE THUNDERSTORM
OUTFLOWS IN THE AREA. ASSUMING THE LEADING EDGE OF STRONGER
NORTHEAST WINDS IN NORTH CAROLINA IS THE ACTUAL FRONT...IT CURRENTLY
LIES FROM NEW BERN TO NEAR FAYETTEVILLE AND IS DROPPING SOUTHWARD AT
AROUND 12 KNOTS.
AS THIS WIND SHIFT/FRONT ARRIVES LATER TONIGHT...LIGHT EASTERLY
WINDS WILL SHIFT TO THE NORTHEAST AND INCREASE TO AROUND 15 KNOTS.
THIS WILL BUILD SEAS FRONT THE CURRENTLY-OBSERVED 1.5-2 FEET UP TO
3-4 FEET BY DAYBREAK SUNDAY.
THUNDERSTORM ACTIVITY HAS BEEN RATHER WIDESPREAD THIS AFTERNOON AND
EARLY THIS EVENING. ANOTHER CONVECTIVE CLUSTER LOOKS TO TARGET THE
MYRTLE BEACH AREA IN THE NEXT HOUR...WITH ADDITIONAL SHOWERS AND
POSSIBLE THUNDERSTORMS ACCOMPANYING THE WIND SHIFT/FRONT LATER
TONIGHT. MONITOR OUR LATEST MARINE WEATHER STATEMENTS OR WARNINGS
WHICH WILL BE ISSUED FOR PARTICULARLY DANGEROUS STORMS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...THE GRADIENT WILL BE TIGHTENING UP DURING
THIS PERIOD. A NE SURGE SUNDAY WILL BECOME FORTIFIED BY A TIGHTENING
PRESSURE GRADIENT BETWEEN HIGH PRESSURE ACROSS THE NORTHEAST U.S.
AND A DEVELOPING TROPICAL LOW ACROSS THE BAHAMAS. THIS WILL SERVE TO
NOT ONLY PROLONG THE NE FLOW...BUT TO INCREASE ITS MAGNITUDE.
THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED BEGINNING SUNDAY
MORNING. WINDS WILL COMMONLY BE SUSTAINED AT 20 TO 25 KT. A NE FETCH
WILL BUILD SEAS TO 4 TO 7 FT AND 8 FT OR HIGHER BEYOND 20 NM.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...THE MARINE COMMUNITY CAN EXPECT A
NORTHEAST FLOW TUESDAY ON THE ORDER OF 15-20 KNOTS. THIS FLOW WILL
DIMINISH QUITE A BIT WEDNESDAY ESSENTIALLY BECOMING VARIABLE BY
DAYS END. FOR THURSDAY A VERY LIGHT FLOW CAN BE EXPECTED AS THE
WATERS ARE IN BETWEEN RETREATING HIGH PRESSURE TO THE NORTH AND
THE BUILDING BERMUDA RIDGE. WILL LIKELY SEE WINDS MORE INFLUENCED
BY THE SEA BREEZE THIS DAY. SIGNIFICANT SEAS CONTINUE TO BE
PROBLEMATIC DEPENDING ON THE TRACK AND INTENSITY OF AL96. FORECAST
SHOWS 2-6 FEET TUESDAY WITH AN INCREASE MOSTLY IN THE OUTER WATERS
WEDNESDAY AND THURSDAY DUE ALMOST EXCLUSIVELY TO INCREASED SWELL
COMPONENT FROM THE AFOREMENTIONED SYSTEM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 8 PM EDT MONDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...JDW/MRR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
937 PM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 921 PM CDT SAT AUG 23 2014
SEVERAL AREAS OF HEAVY RAIN REMAIN A CONCERN THIS EVENING AND
OVERNIGHT. FIRST...THE FLASH FLOOD WATCH HAS BEEN TRIMMED TO
INCLUDE NOW THE AREAS ALONG AND NORTH OF LAKE SAKAKAWEA AS THE
RAIN SHIELD HAS MOVED NORTH. THIS REPRESENTS FUTURE FLOOD
POTENTIAL TONIGHT AND SUNDAY. TWO AREAS THAT HAVE ALREADY RECEIVED
HEAVY RAIN AND REPORTED OVERLAND FLOODING HAVE FLOOD ADVISORIES
ONGOING. THE FIRST AREA INCLUDES DICKEY AND LAMOURE COUNTIES WHERE
ONGOING TRAINING THUNDERSTORMS LEFT STREET FLOODING IN ELLENDALE.
THE HEAVY RAINFALL SHOULD LAST ANOTHER COUPLE OF HOURS FOLLOWED BY
SLOWLY RECEDING WATER. ANOTHER FLOOD ADVISORY REMAINS IN EFFECT FOR
THE SOUTHWEST WHERE WIDESPREAD 2 INCHES OF RAIN FELL TODAY. WITHIN
THIS AREA AN ENHANCED AREA OF HEAVY RAINFALL...PERHAPS UP TO 4
INCHES...STRETCHES FROM WESTERN SIOUX...CENTRAL GRANT...CENTRAL
MORTON COUNTY NEAR GLEN ULLIN...INTO MERCER COUNTY. WILL KEEP THE
FLOOD ADVISORY GOING FOR THIS AREA AS WELL TONIGHT.
UPDATE ISSUED AT 717 PM CDT SAT AUG 23 2014
FIRST WAVE OF HEAVY RAIN HAS PASSED THROUGH THE SOUTHWEST. SO FAR
WIDESPREAD REPORTS OF AROUND 2 INCHES WITH UPWARDS OF 3 INCHES IN
PLACES. THE RAIN SHIELD IS MOVING INTO THE NORTH CENTRAL FOR THE
REMAINDER OF THE EVENING. SEVERAL LONG LIVED THUNDERSTORMS MOVING
THROUGH NORTHWEST SOUTH DAKOTA SO WILL KEEP FLASH FLOOD WATCH AND
ADVISORIES GOING SOUTHWEST FOR A LITTLE WHILE LONGER. CLUSTER OF
MORE VIGOROUS THUNDERS TOMS MOVING TROUGH SOUTHEAST NORTH DAKOTA.
SEVERE POTENTIAL LIMITED WIND GUSTS TO 40 AND HEAVY RAIN LIKELY
THERE. MID 50S FOR THE HIGH TEMP TODAY NORTHWEST NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE HEAVY
RAIN LATE THIS AFTERNOON AND THIS EVENING. THEN ENDING ACROSS THE
SOUTH LATE THIS EVENING BUT CONTINUING ACROSS THE NORTH INTO
SUNDAY.
LATEST RADAR ESTIMATES HAVE MATCHED UP WELL WITH OBSERVED REPORTS
ACROSS SOUTHWEST NORTH DAKOTA. GENERALLY 1 TO 1.5 INCHES REPORTED
SOUTH AND WEST OF A LINE FROM SELFRIDGE TO THEODORE ROOSEVELT NP.
DID GET A REPORT FROM WFO BILLINGS OF CLOSER TO 5 INCHES NEAR
BAKER MT. AS OF YET CALLS TO SPOTTERS AND BOWMAN EM HAVE RESULTED
IN NO SIGNIFICANT FLOODING ISSUES. HOWEVER...WE HAVE ISSUED AN
AREAL FLOOD ADVISORY SOUTH AND WEST OF LAKE SAKAKAWEA AND THE
MISSOURI RIVER...TO COVER THE 1 TO 1.5 INCHES OF RAIN THAT HAS
FALLEN IN ADDITION TO ADDITIONAL EXPECTED RAIN THROUGH THE
AFTERNOON AND TONIGHT.
REGARDING THE CURRENT FLOOD WATCH AND POTENTIAL OF SEVERE
WEATHER...
WILL LET THE WATCH CONTINUE. HEAVIEST RAIN HAS FALLEN
ACROSS THE MOST SATURATED SOILS IN THE SOUTHWEST. THE HEAVIEST
ADDITIONAL ACCUMULATIONS TONIGHT SHOULD BE CENTERED ACROSS THE
NORTH CENTRAL AND NORTHWEST. IF WE HAD TO PARE IT DOWN...WOULD
PROBABLY REMOVE WELLS SOUTH THROUGH MCINTOSH. HOWEVER...THERE IS
STILL A THREAT OF AFTERNOON AND EVENING CONVECTION HERE AS THE
SURFACE LOW LIFTS INTO NORTH DAKOTA. THUS WILL CONTINUE AS IS FOR
NOW. THE LATEST HRRR STILL DEVELOPS SCATTERED CONVECTION IN THIS
AREA THIS EVENING. HOWEVER THE STRONGEST CONVECTION IS NOW BEING
PLACED TO THE SOUTH OF THE CWA. WITH OUR EAST TO NORTHEAST FLOW AND
COOLER TEMPERATURES OVER NORTH DAKOTA THIS SEEMS REASONABLE...BUT
WITH THE SURFACE LOW LIFTING INTO CENTRAL NORTH DAKOTA THINK OUR
SOUTHEAST CWA WILL BE IN A FAVORED LOCATION FOR ABUNDANT LOW LEVEL
HELICITY THUS WILL CONTINUE A MENTION OF SEVERE OVER THE SOUTHEAST
CWA.
WE DRY OUT FROM SOUTH TO NORTH LATE THIS EVENING THROUGH SUNDAY.
HIGHEST POPS WILL REMAIN OVER THE NORTHWEST AND FAR NORTH CENTRAL.
WITH THE UPPER LEVEL SLOW LIFTING THROUGH EASTERN MONTANA INTO
NORTHWEST ND...THERE SHOULD STILL BE ENOUGH MID TO UPPER LEVEL
FORCING TO MENTION ISOLATED THUNDER THROUGH THE DAY WHEREVER WE
HAVE A MENTION OF SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
SUNDAY EVENING THE UPPER LEVEL LOW IS PROGGED TO BE AT THE BORDER OF
MONTANA AND NORTH DAKOTA...WITH THE SURFACE LOW ALONG THE NORTH
DAKOTA/CANADIAN/MINNESOTA BORDER. THE ELONGATED SURFACE LOW/FRONT
COMBINED WITH THE UPPER LOW TO THE WEST WILL KEEP HIGH CHANCES OF
SHOWERS IN THE NORTHWEST/NORTH CENTRAL SUNDAY NIGHT.
THE SYSTEM LIFTS NORTHEASTWARD SUNDAY NIGHT AND INTO MONDAY...WITH
COLD ADVECTION IN ITS WAKE. LOOKING AT LOWS SUNDAY NIGHT IN THE 40S
WEST TO LOWER 50S IN THE JAMES VALLEY. MOSTLY CLOUDY SKIES NORTH
MONDAY WILL KEEP MAXIMUM TEMPERATURES CONFINED TO THE UPPER 50S WITH
60S SOUTH. BY TUESDAY MORNING THE SURFACE HIGH SETTLES OVER NORTH
DAKOTA...AND LOW TEMPERATURES SHOULD BE IN THE 40S ACROSS WESTERN
AND CENTRAL NORTH DAKOTA.
DURING THE DAY TUESDAY THROUGH WEDNESDAY THE TRAILING UPPER LEVEL
TROUGH MOVES EAST ACROSS THE NORTHERN PLAINS...WITH ISOLATED TO
SCATTERED SHOWERS POSSIBLE. MINOR UPPER LEVEL RIDGING OCCURS
WEDNESDAY NIGHT THROUGH FRIDAY. THE APPROACH OF ANOTHER ROCKIES
TROUGH TOWARDS NEXT WEEKEND MAY BE THE NEXT CHANCE OF SHOWERS AND
THUNDERSTORMS. A SLOW WARMING TREND WITH HIGHS TUESDAY IN THE 60S
WARMING TO THE 80S BY FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 921 PM CDT SAT AUG 23 2014
MAIN HAZARDS TO AVIATION CENTER AROUND A LARGE WET WEATHER PATTERN
BRINGING WIDESPREAD IFR CONDITIONS ACROSS WESTERN/CENTRAL NORTH DAKOTA.
LARGE SURFACE LOW PRESSURE CENTERED IN SOUTHWEST SOUTH DAKOTA WILL
MAINTAIN MOISTURE AND SUFFICIENT UPSLOPE FLOW TO KEEP CEILINGS LOW
AND VSBYS...WHEN NOT IMPACTED BY SHOWERS...FOG. SLOW IMPROVEMENT
EXPECTED SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 300 PM CDT SAT AUG 23 2014
MODERATE TO HEAVY RAINS OVER THE PAST WEEK HAVE KEPT SOIL MOISTURE
ABNORMALLY HIGH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. RAINFALL
THAT OCCURRED TODAY...ALONG WITH THE EXPECTED RAINFALL INTO TONIGHT
MAY LIKELY LEAD TO SOME OVERLAND FLOODING...ALONG WITH INCREASED
FLOWS INTO CREEKS...STREAMS...AND RIVERS.
ALONG WITH THE FLOOD WATCH THAT WAS ISSUED ON FRIDAY FOR TODAY
THROUGH SUNDAY...HAVE ALSO ISSUED AN AREAL FLOOD ADVISORY FOR THE
AREA SOUTH AND WEST OF THE MISSOURI RIVER. RADAR ESTIMATES WERE IN
AGREEMENT WITH SOME RAINFALL REPORTS OF 1 TO 1.5 INCHES OF RAINFALL
SO FAR TODAY. IN ADDITION...WHILE THERE IS NO REASONABLE EXPECTATION
OF MAJOR RIVER FLOODING...AT A MINIMUM THERE WILL BE SIGNIFICANT
WITHIN BANK RISES...AND MINOR RIVER FLOODING CANNOT BE RULED OUT.
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
017>023-031>036-040>047-050.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
021>023.
&&
$$
UPDATE...WAA
SHORT TERM...TWH
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
729 PM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 717 PM CDT SAT AUG 23 2014
FIRST WAVE OF HEAVY RAIN HAS PASSED THROUGH THE SOUTHWEST. SO FAR
WIDESPREAD REPORTS OF AROUND 2 INCHES WITH UPWARDS OF 3 INCHES IN
PLACES. THE RAIN SHIELD IS MOVING INTO THE NORTH CENTRAL FOR THE
REMAINDER OF THE EVENING. SEVERAL LONG LIVED THUNDERSTORMS MOVING
THROUGH NORTHWEST SOUTH DAKOTA SO WILL KEEP FLASH FLOOD WATCH AND
ADVISORIES GOING SOUTHWEST FOR A LITTLE WHILE LONGER. CLUSTER OF
MORE VIGOROUS THUNDERS TOMS MOVING TROUGH SOUTHEAST NORTH DAKOTA.
SEVERE POTENTIAL LIMITED WIND GUSTS TO 40 AND HEAVY RAIN LIKELY
THERE. MID 50S FOR THE HIGH TEMP TODAY NORTHWEST NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE HEAVY
RAIN LATE THIS AFTERNOON AND THIS EVENING. THEN ENDING ACROSS THE
SOUTH LATE THIS EVENING BUT CONTINUING ACROSS THE NORTH INTO
SUNDAY.
LATEST RADAR ESTIMATES HAVE MATCHED UP WELL WITH OBSERVED REPORTS
ACROSS SOUTHWEST NORTH DAKOTA. GENERALLY 1 TO 1.5 INCHES REPORTED
SOUTH AND WEST OF A LINE FROM SELFRIDGE TO THEODORE ROOSEVELT NP.
DID GET A REPORT FROM WFO BILLINGS OF CLOSER TO 5 INCHES NEAR
BAKER MT. AS OF YET CALLS TO SPOTTERS AND BOWMAN EM HAVE RESULTED
IN NO SIGNIFICANT FLOODING ISSUES. HOWEVER...WE HAVE ISSUED AN
AREAL FLOOD ADVISORY SOUTH AND WEST OF LAKE SAKAKAWEA AND THE
MISSOURI RIVER...TO COVER THE 1 TO 1.5 INCHES OF RAIN THAT HAS
FALLEN IN ADDITION TO ADDITIONAL EXPECTED RAIN THROUGH THE
AFTERNOON AND TONIGHT.
REGARDING THE CURRENT FLOOD WATCH AND POTENTIAL OF SEVERE
WEATHER...
WILL LET THE WATCH CONTINUE. HEAVIEST RAIN HAS FALLEN
ACROSS THE MOST SATURATED SOILS IN THE SOUTHWEST. THE HEAVIEST
ADDITIONAL ACCUMULATIONS TONIGHT SHOULD BE CENTERED ACROSS THE
NORTH CENTRAL AND NORTHWEST. IF WE HAD TO PARE IT DOWN...WOULD
PROBABLY REMOVE WELLS SOUTH THROUGH MCINTOSH. HOWEVER...THERE IS
STILL A THREAT OF AFTERNOON AND EVENING CONVECTION HERE AS THE
SURFACE LOW LIFTS INTO NORTH DAKOTA. THUS WILL CONTINUE AS IS FOR
NOW. THE LATEST HRRR STILL DEVELOPS SCATTERED CONVECTION IN THIS
AREA THIS EVENING. HOWEVER THE STRONGEST CONVECTION IS NOW BEING
PLACED TO THE SOUTH OF THE CWA. WITH OUR EAST TO NORTHEAST FLOW AND
COOLER TEMPERATURES OVER NORTH DAKOTA THIS SEEMS REASONABLE...BUT
WITH THE SURFACE LOW LIFTING INTO CENTRAL NORTH DAKOTA THINK OUR
SOUTHEAST CWA WILL BE IN A FAVORED LOCATION FOR ABUNDANT LOW LEVEL
HELICITY THUS WILL CONTINUE A MENTION OF SEVERE OVER THE SOUTHEAST
CWA.
WE DRY OUT FROM SOUTH TO NORTH LATE THIS EVENING THROUGH SUNDAY.
HIGHEST POPS WILL REMAIN OVER THE NORTHWEST AND FAR NORTH CENTRAL.
WITH THE UPPER LEVEL SLOW LIFTING THROUGH EASTERN MONTANA INTO
NORTHWEST ND...THERE SHOULD STILL BE ENOUGH MID TO UPPER LEVEL
FORCING TO MENTION ISOLATED THUNDER THROUGH THE DAY WHEREVER WE
HAVE A MENTION OF SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
SUNDAY EVENING THE UPPER LEVEL LOW IS PROGGED TO BE AT THE BORDER OF
MONTANA AND NORTH DAKOTA...WITH THE SURFACE LOW ALONG THE NORTH
DAKOTA/CANADIAN/MINNESOTA BORDER. THE ELONGATED SURFACE LOW/FRONT
COMBINED WITH THE UPPER LOW TO THE WEST WILL KEEP HIGH CHANCES OF
SHOWERS IN THE NORTHWEST/NORTH CENTRAL SUNDAY NIGHT.
THE SYSTEM LIFTS NORTHEASTWARD SUNDAY NIGHT AND INTO MONDAY...WITH
COLD ADVECTION IN ITS WAKE. LOOKING AT LOWS SUNDAY NIGHT IN THE 40S
WEST TO LOWER 50S IN THE JAMES VALLEY. MOSTLY CLOUDY SKIES NORTH
MONDAY WILL KEEP MAXIMUM TEMPERATURES CONFINED TO THE UPPER 50S WITH
60S SOUTH. BY TUESDAY MORNING THE SURFACE HIGH SETTLES OVER NORTH
DAKOTA...AND LOW TEMPERATURES SHOULD BE IN THE 40S ACROSS WESTERN
AND CENTRAL NORTH DAKOTA.
DURING THE DAY TUESDAY THROUGH WEDNESDAY THE TRAILING UPPER LEVEL
TROUGH MOVES EAST ACROSS THE NORTHERN PLAINS...WITH ISOLATED TO
SCATTERED SHOWERS POSSIBLE. MINOR UPPER LEVEL RIDGING OCCURS
WEDNESDAY NIGHT THROUGH FRIDAY. THE APPROACH OF ANOTHER ROCKIES
TROUGH TOWARDS NEXT WEEKEND MAY BE THE NEXT CHANCE OF SHOWERS AND
THUNDERSTORMS. A SLOW WARMING TREND WITH HIGHS TUESDAY IN THE 60S
WARMING TO THE 80S BY FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 717 PM CDT SAT AUG 23 2014
MAIN HAZARDS TO AVIATION CENTER AROUND A LARGE WET WEATHER PATTERN
BRINGING WIDESPREAD IFR CONDITIONS ACROSS WESTERN NORTH DAKOTA.
LARGE SURFACE LOW PRESSURE CENTERED IN SOUTHWEST SOUTH DAKOTA WILL
MAINTAIN MOISTURE AND SUFFICIENT UPSLOPE FLOW TO KEEP CEILINGS LOW
AND VSBYS...WHEN NOT IMPACTED BY SHOWERS...FOG. SLOW IMPROVEMENT
EXPECTED SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 300 PM CDT SAT AUG 23 2014
MODERATE TO HEAVY RAINS OVER THE PAST WEEK HAVE KEPT SOIL MOISTURE
ABNORMALLY HIGH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. RAINFALL
THAT OCCURRED TODAY...ALONG WITH THE EXPECTED RAINFALL INTO TONIGHT
MAY LIKELY LEAD TO SOME OVERLAND FLOODING...ALONG WITH INCREASED
FLOWS INTO CREEKS...STREAMS...AND RIVERS.
ALONG WITH THE FLOOD WATCH THAT WAS ISSUED ON FRIDAY FOR TODAY
THROUGH SUNDAY...HAVE ALSO ISSUED AN AREAL FLOOD ADVISORY FOR THE
AREA SOUTH AND WEST OF THE MISSOURI RIVER. RADAR ESTIMATES WERE IN
AGREEMENT WITH SOME RAINFALL REPORTS OF 1 TO 1.5 INCHES OF RAINFALL
SO FAR TODAY. IN ADDITION...WHILE THERE IS NO REASONABLE EXPECTATION
OF MAJOR RIVER FLOODING...AT A MINIMUM THERE WILL BE SIGNIFICANT
WITHIN BANK RISES...AND MINOR RIVER FLOODING CANNOT BE RULED OUT.
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
017>023-031>036-040>047-050.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
017>023-031>036-040>047-050.
&&
$$
UPDATE...WAA
SHORT TERM...TWH
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
405 AM CDT FRI AUG 22 2014
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 403 AM CDT FRI AUG 22 2014
WITH THE UPPER AIR PATTERN, THE GFS AND ECMWF WERE SIMILAR AND
FASTER THAN THE NAM AND THE GEM. NAM WAS THE SLOWEST MODEL. AT THE
SURFACE, THE ECMWF WAS THE SLOWEST SOLUTION OF THE SET. WILL PREFER
THE ECMWF.
WATER VAPOR LOOP INDICATED A SHORT WAVE TROUGH OVER THE MT/ND
BORDER. SHORT WAVE TROUGH FORECAST TO MOVE INTO SOUTHERN MAN THIS
AFTERNOON. WILL HAVE SCATTERED PRECIP OVER THE NORTHERN ZONES FOR
TODAY.
ALSO WATER VAPOR LOOP INDICATED UPPER LEVEL LOW OVER THE PACIFIC
NORTHWEST IS FORECAST TO AMPLIFY TODAY, THEN WEAKENS A BIT. TROUGH
MOVES OUT OF THE ROCKIES AND TAKES ON A NEGATIVE TILT AND
INTENSIFIES AGAIN AFTER 72 HOURS.
ALSO UPPER LEVEL LOW OVER THE DESERT SOUTHWEST WILL MOVE INTO THE
NORTHERN PLAINS SAT/SAT NIGHT/SUN AND PRODUCE ANOTHER ROUND OF
PRECIP. 700 THETA-E RIDGE ALSO MOVES OVER THE AREA. PRECIPITABLE
WATER RISES TO TO OVER 2 INCHES BY SAT. WILL ADD THREAT OF HEAVY
RAIN FOR SAT AFTERNOON AND SAT NIGHT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 403 AM CDT FRI AUG 22 2014
/MON THROUGH FRI/
THE LONG RANGE MODELS ARE SOMEWHAT IN AGREEMENT FOR NEXT WEEK WITH A
CHANGING UPPER LEVEL PATTERN...HOWEVER THE GFS IS FASTER WITH A
SHARP SHORT WAVE CROSSING THE NORTHERN PLAINS MID WEEK. IT IS ALSO
MUCH DRIER WITH THE ECMWF KEEPING PRECIP ACROSS THE SOUTHEASTERN
CWA. DRY POPS FOR THE MAJORITY OF THE CWA (MOST OF ND AND NW MN) ON
MON/TUE SEEM REASONABLE WITH UPPER PATTERN KEEPING BEST ENERGY FROM
CENTRAL PLAINS INTO THE GREAT LAKES. BY WED/THU THE GFS BUILDS A
RIDGE OVER SASKATCHEWAN WHILE THE ECMWF IS A BIT FURTHER WEST WITH
THE RIDGE AXIS AND ALSO LESS AMPLIFIED. DAY SIX SHOWING SOME LIGHT
PRECIP OVER AREA WITH THE NW FLOW PATTERN BECOMING DRY AT
NIGHT...WHICH SEEMS REASONABLE FOR NW UPPER FLOW PATTERN. FOR LATE
IN THE WEEK THE GFS CONTINUES TO AMPLIFY THE UPPER RIDGE OVER THE
NORTHERN TIER AND MB...KEEPING THINGS DRY...WHILE THE ECMWF HAS MORE
ZONAL FLOW WITH WAVES MOVING ACROSS SRN CANADA. WILL LOWER INHERITED
CHANCE POPS FOR THE END OF THE WEEK. SIGNIFICANT DIFFERENCE IN MODEL
SOLUTION BEGIN ON FRI...WITH THE GFS SHOWING A STRONG LOW BRINGING
PRECIP TO THE AREA AND THE ECMWF CONTINUES THE ZONAL FLOW
PATTERN...GIVING ME VERY LOW CONFIDENCE IN SOLUTION FOR DAY 7.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1135 PM CDT THU AUG 21 2014
THE HRRR INDICATES A FAIRLY STRONG SIGNAL FOR IFR/LIFR CONDITIONS
DEVELOPING OVERNIGHT. THEREFORE...GIVEN THE HIGH SFC MOISTURE WILL
TAKE CIGS DOWN INTO THE IFR CATEGORY FOR ALL SITES OVERNIGHT. LOW
CIGS AND FOG COULD LINGER WELL INTO FRI MORNING/EARLY AFTERNOON
WITH PLENTY OF LOW LEVEL MOISTURE...BUT WILL ATTEMPT TO IMPROVE
CONDITIONS INTO MVFR CATEGORY BY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...HOPPES
LONG TERM...SPEICHER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1136 PM CDT THU AUG 21 2014
.UPDATE...
ISSUED AT 1135 PM CDT THU AUG 21 2014
WE ARE STILL GETTING SOME SHOWERS MAINLY IN THE NORTH
WHERE LINGERING INSTABILITY NEAR THE SFC BOUNDARY PERSISTS. THIS
CONVECTION COULD LINGER THROUGH THE NIGHT...AND WITH A SHORTWAVE
MOVING INTO THE NORTH LATE TONIGHT...WILL MENTION SOME LOW POPS
FOR SHOWERS THROUGH THE NIGHT. OTHERWISE...NO CHANGE FROM PREVIOUS
UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU AUG 21 2014
THE MAIN FORECAST CHALLENGE CONCERNS PCPN CHANCES AND
TEMPERATURES. NAM/RUC INITIALIZED BEST HOWEVER NAM LOOKS TO BE
THE ODD MODEL OUT IN LATER PERIODS AND DISCARDED. OPERATIONAL
MODELS CONTINUE TO OVER FORECAST PCPN ACROSS THE REGION
SIGNIFICANTLY. ABOUT THE ONLY THING MODELS AGREE ON IS THAT THE
REGION WILL PERSIST IN SW FLOW ALOFT THROUGH THE PERIOD.
FOR TONIGHT SURFACE LOW ALONG ND/SD/MN BORDER AREA WILL CONTINUE
TO DRIFT EAST. TRAILING SURFACE BOUNDARY WILL ROUGHLY BISECT FA
FROM NW-SE. WATER VAPOR LOOP INDICATING WEAK IMPULSE MOVING INTO
THE CENTRAL DAKOTAS WHICH WILL LIFT NE TONIGHT. WITH IMPULSE AND
BOUNDARY WILL MAINTAIN SOME MODEST POPS THROUGH THE EVENING. ONCE
THE WAVE LIFTS NE LATER TONIGHT A RIDGE OF HIGH PRESSURE NOSING IN
SHOULD KEEP MOST AREAS DRY. CLOUDS MOST AREAS AT LEAST PART OF THE
NIGHT AND ELEVATED DEWPOINTS WILL KEEP MINIMUMS GENERALLY IN THE
60S.
WEAK SURFACE HIGH PRESSURE WILL CONTINUE ACROSS THE FA ON
FRIDAY/FRIDAY NIGHT. ALOFT IN SW FLOW ANOTHER WEAK WAVE WILL TO LIFT
NE. POTENTIALLY THE MOST ACTIVE AREA WILL BE TO OUR WEST HOWEVER
SOME PCPN MAY CLIP DVL BASIN SO WILL MAINTAIN SOME LOW POPS.
REMAINDER OF THE FA SHOULD FOR THE MOST PART BE DRY. TEMPERATURES
WILL HINGE ON CLOUD TRENDS SO HELD PRETTY CLOSE TO CURRENT VALUES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU AUG 21 2014
POOR MODEL AGREEMENT THROUGH SUNDAY AS UPPER LOW CROSSES NORTHERN
ROCKIES INTO THE NORTHERN HIGH PLAINS. ALL SHOWING DIFFERENT
SOLUTIONS ON TRACK/TIMING OF UPPER LOW AND ASSOCIATED SURFACE
FEATURES. GENERAL THOUGHT IS THAT LOW PRESSURE WILL ORGANIZE OVER
THE CENTRAL PLAINS/HIGH PLAINS AND LIFT NE THROUGH THE LATER HALF
OF THE WEEKEND. WITH DIFFERING SOLUTIONS ON LOW LEVEL FEATURES
TRYING FINE TUNE FAVORED LOCATIONS FOR SIGNIFICANT PCPN VERY
DIFFICULT AT THIS TIME. AS A RESULT MADE MINIMAL CHANGES TO POPS
IN LATER PERIODS. LITTLE CHANGE IN THERMAL PROFILES SO AGAIN
TEMPERATURES WILL HINGE ON CLOUD COVER BUT LIKELY TO REMAIN BLO
AVERAGE.
FOR SUNDAY NIGHT THROUGH WEDNESDAY...MODELS COMING INTO BETTER
AGREEMENT AT THIS POINT...BUT GFS SFC FEATURES AND PCPN BECOME THE
OUTLIER. THEREFORE...A BLENDED ECMWF/GEM SOLN IS PREFERRED ATTM.
OTHERWISE...SFC LOW PRESSURE DEVELOPING OVER THE UPPER MIDWEST IS
EXPECTED TO LIFT TO THE NE. UPPER LEVEL TROF LOOKS TO CROSS THE AREA
BRINGING COOLER AIR BEHIND THE SYSTEM...AND FRONTOGENETICAL FORCING
TO TRIGGER -SHRA/-TSRA ALONG AND AHEAD OF THE LOW. SUFFICIENT LL
MOISTURE AVAILABLE TO WRAP BEHIND THE SYSTEM...KEEPING SKIES MOSTLY
CLOUDY. AS THE UPPER TROF DIGS IN...LOOK FOR COOLER TEMPS TO ROUND
OUT THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1135 PM CDT THU AUG 21 2014
THE HRRR INDICATES A FAIRLY STRONG SIGNAL FOR IFR/LIFR CONDITIONS
DEVELOPING OVERNIGHT. THEREFORE...GIVEN THE HIGH SFC MOISTURE WILL
TAKE CIGS DOWN INTO THE IFR CATEGORY FOR ALL SITES OVERNIGHT. LOW
CIGS AND FOG COULD LINGER WELL INTO FRI MORNING/EARLY AFTERNOON
WITH PLENTY OF LOW LEVEL MOISTURE...BUT WILL ATTEMPT TO IMPROVE
CONDITIONS INTO MVFR CATEGORY BY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...HOPKINS/VOELKER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
513 PM EDT FRI AUG 22 2014
.SYNOPSIS...
ROUNDS OF SHOWERS AND THUNDERSTORMS CONTINUE WITH OCCASIONAL
DOWNPOURS...AS WEAK DISTURBANCES RIDE SE. HIGH PRESSURE WILL TRY TO
NOSE IN FROM THE NORTHEAST EARLY NEXT WEEK AS UPPER RIDGE BUILDS.
&&
.NEAR TERM /THROUGH SATURDAY/...
21Z UPDATE...
NO MAJOR CHANGES...UPDATED PRECIPITATION TO BE A BIT MORE
REPRESENTATIVE OF THE CURRENT SITUATION AND THE MOST CURRENT RUC
AND HRRR MODEL RUNS.
OLD BELOW...
THE AREA WILL REMAIN IN THE WARM AND HUMID SECTOR WITH FRONTAL
BOUNDARIES TO THE NORTH AND WEST. ALOFT...NORTHWEST FLOW AHEAD OF
AN H5 RIDGE COULD BRING SOME IMPULSES OF ENERGY TO KEEP SHOWERS
AND THUNDERSTORMS GOING THIS EVENING INTO EARLY SATURDAY MORNING.
RADAR INDICATED AT 18Z...STORMS DEVELOPING ALONG INTERSTATE 64
FROM HTS TO CRW AND SOUTH...MOVING SOUTHEAST. SOME OF THE
STRONGEST STORMS WILL BE CAPABLE TO PRODUCE ONE INCH PER HOUR.
WITH NEARLY SATURATED TERRAIN...DECIDED TO KEEP THE FLASH FLOOD
WATCH IN PLACE THROUGH TONIGHT.
PREVIOUS TEMPERATURES LOOKS GOOD. DECREASED COUPLE OF DEGREES ON
SATURDAYS HIGHS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
DRIER WX REGIME BEGINS TO SET IN AS UPPER RIDGE BUILDS INTO THE
AREA. IT WILL BE WARM...BUT NOT HOT AS THE OPPRESSIVE HEAT REMAINS
WELL W OF THE REGION. IT WILL STILL BE RATHER MUGGY
THOUGH...TYPICAL DOG DAYS OF SUMMER.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
USED WPC THINKING WITH SOME TWEAKS. HIGH PRESSURE...AT THE SURFACE
AND ALOFT...WILL DOMINATE THE REGION INTO WEDNESDAY NIGHT...BEFORE
WEAKENING. THIS WILL ALLOW A COLD FRONT TO PUSH SOUTH INTO THE AREA
ON THURSDAY...WITH THIS FEATURE EXPECTED DRIFT SOUTH THROUGH THE
REMAINDER OF THE PERIOD.
WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
21Z UPDATE...
UPDATED CEILINGS AND PRECIPITATION TO BE REPRESENTATIVE OF THE
CURRENT CONDITIONS. NO MAJOR CHANGES MADE.
OLD BELOW...
RADAR IMAGES SHOW STORMS DEVELOPING SOUTH AND ALONG
A LINE FROM CRW TO BKW AT 18Z. THESE STORMS WILL AFFECT BKW
DIRECTLY WITH MVFR/IFR CONDITIONS UNDER STORMS. PCPN ACTIVITY IS
EXPECTED TO DECREASE AFTER SUNSET. HOWEVER...ADDITIONAL CONVECTION
COULD DEVELOP OVERNIGHT INTO EARLY SATURDAY.
WITH VERY HIGH HUMIDITY IN THE LOW TO MID LEVELS...EVIDENT IN SFC
DEWPOINTS IN THE LOWER 70S...AND PWATS EXCEEDING 2 INCHES...LOW
LEVEL CLOUDS WILL LIKELY DEVELOP OVERNIGHT FOR PERIODS OF IFR
CONDITIONS ESPECIALLY OVER THE HIGHER TERRAIN.
LOCALIZED DOWNPOURS CAN PRODUCE BRIEF IFR VSBY AND CEILINGS AT TIMES.
CEILINGS BECOMING MAINLY 2 TO 3 THSD FT BKN WITH LAYERS AND VSBY
5 TO 6 MILES IN HAZE AFTER ABOUT 22Z. YET...ADDITIONAL CLUSTERS
OF SHOWERS AND STORMS LIKELY...INTO THE EVENING HOURS...AGAIN WITH
IFR VSBY AND CEILINGS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: DURATION AND TIMING ROUNDS OF CONVECTION WILL
VARY. AT LEAST SOME AREAS OF PCPN MAY EVEN LINGER LONGER FRIDAY
NIGHT...BUT NOT MENTIONED IN TAFS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H M M M M M M H H H M
HTS CONSISTENCY M M M M H H H H H H H H
BKW CONSISTENCY M M M M M M M M M H H H
EKN CONSISTENCY H H H H H H H H H H H M
PKB CONSISTENCY M M M M M M M M M H H H
CKB CONSISTENCY H H M M M M M M M H H H
AFTER 18Z SATURDAY...
IFR CONDITIONS POSSIBLE IN LOW STRATUS IN LINGERING LOW LEVEL
MOISTURE SATURDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH UNTIL 1 AM EDT SATURDAY FOR WVZ005>011-
013>020-024>040-046-047.
OH...FLASH FLOOD WATCH UNTIL 1 AM EDT SATURDAY FOR OHZ066-067-075-
076-083>087.
KY...FLASH FLOOD WATCH UNTIL 1 AM EDT SATURDAY FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH UNTIL 1 AM EDT SATURDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...ARJ/30
NEAR TERM...ARJ/LS
SHORT TERM...30
LONG TERM...JSH
AVIATION...ARJ/LS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
625 AM EDT FRI AUG 22 2014
.SYNOPSIS...
ROUNDS OF SHOWERS AND THUNDERSTORMS CONTINUE WITH OCCASIONAL
DOWNPOURS...AS WEAK DISTURBANCES RIDE SE. HIGH PRESSURE WILL TRY TO
NOSE IN FROM THE NORTHEAST EARLY NEXT WEEK AS UPPER RIDGE BUILDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE AT 625 AM...THOUGHT FOR A MOMEMT THERE MAY BE A GAP WITH NO
SHOWERS...BETWEEN THE LARGER CLUSTERS OF CONVECTION THIS MORNING.
THEN NEW SMALL CELLS FORM VCNTY CRW ON INTO SE OHIO AROUND 10Z.
WILL BE A BIT FASTER BRINGING NEXT LKLY POP INTO SE OHIO THIS
MORNING.
THE REST IS FROM THE 415 AM DISCUSSION...
ENTERING INTO THE PEAK OF THE FLASH FLOOD CONCERN - NOW INTO TONIGHT.
BEST LOW LEVEL INFLOW AT 925 MB IS ONGOING WITH 20 TO 30 KNOT
UNDISTURBED FEED UP THE OHIO VALLEY AND INTO THE WNW TO ESE
BAROCLINIC ZONE. 925 MB REDUCES TO 10 TO 15 KNOTS AFTER 18Z TODAY.
SEVERAL SMALL MID LEVEL 500 MB VORT MAXIMUMS IN THE NW FLOW ALOFT.
ONE PASSES CROSSES SRN WV MOUNTAINS AROUND 12Z. 07Z RAP HAS ANOTHER
ALONG INDIANA/OHIO BORDER BY THEN. HOWEVER...EVEN AT 08Z...MORE
STORMS HAVE REACHED INTO WESTERN OHIO. SO...DOING HOURLY POPS WAS
CERTAINLY A CHALLENGE ON THIS GRAVEYARD SHIFT.
EVEN THOUGH THE PKB-CKB AREA DID NOT GET MUCH RAIN ON
THURSDAY...MOST COUNTIES HAVE BEEN AFFECTED PAST WEEK. DID NOT WANT
TO OVER FORECAST WHERE EACH CLUSTER OF STORMS MAY GO AND TRY TO
NARROW DOWN THE WATCH. POSTED A FLASH FLOOD WATCH FOR ENTIRE CWA
THROUGH 05Z SATURDAY. STILL SEEMS THE HEART OF THE CWA MOST
VULNERABLE. EVEN THE 07Z RAP HAS THE AXIS OF MAXIMUM PW FM NRN IL
ESE INTO CENTRAL WV AOA 2 INCHES. HOWEVER...THE SOUTHERN COAL
FIELDS HAVE BEEN THE WETTEST LATELY AND WOULD HAVE THE HIGHEST
RUNOFF PERCENTAGE.
STEERING FLOW TURNS MORE NORTH OVERNIGHT TONIGHT...SO PICTURING THE
TREND WILL BE FOR THE HIGHER POPS TO SINK INTO SOUTHERN COUNTIES
OVERNIGHT. THOUGH AS MENTIONED...LOW LEVEL INFLOW...AS
MENTIONED...NOT AS STRONG.
IN THIS PATTERN...COULD EVEN SEE STRONG RISES ON SOME HEADWATER
RIVERS TONIGHT INTO SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
BOUNDARY CONTINUES SINKING SOUTH SATURDAY...BUT STILL ENOUGH
MOISTURE AROUND TO KICK OFF SOME DIURNALLY DRIVEN SHOWERS AND
STORMS...MAINLY IN THE COAL FIELDS AND WV MOUNTAINS. PRECIP CHANCES
WILL GRADUALLY DECREASE NORTH TO SOUTH THROUGH THE
WEEKEND...EVENTUALLY DRYING OUT ACROSS THE NORTH AS HEIGHTS BUILD
AND A SURFACE HIGH NOSES IN FROM THE NE BY SUNDAY NIGHT.
DESPITE THE BOUNDARY HEADING SOUTH...STILL EXPECTING VERY WARM
TEMPERATURES. MADE ONLY MINIMAL CHANGES TO PREVIOUS HIGHS AND LOWS
BY BLENDING IN BIAS-CORRECTED CONSENSUS GUIDANCE.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
UPPER RIDGE CONTINUES TO BUILD INTO AREA BUT THE OPPRESSIVE HEAT
SHOULD STAY W OF THE AREA. HOWEVER...WE WILL STILL BE CONTENDING
WITH THE MUGGIES WITH TEMPS RUNNING NEAR NORMAL TO PERHAPS
SLIGHTLY ABOVE. A FRONT APPROACHES LONG ABOUT THURSDAY WITH
INCREASING CHANCES FOR SHRA/TSRA.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
ONE ROUNDS OF CONVECTION MOVES THROUGH 06Z TO 12Z WITH LOCALIZED
DOWNPOURS AND IFR VSBY AND CEILING. OTHER DISTURBANCES IN ITS WAKE
WILL RIDE SE AND MAY CAUSE ADDITIONAL CLUSTERS DURING THE
MORNING...FIGURING MORE IN SOUTHERN OHIO INTO WESTERN WEST VIRGINIA
FOR THE 12Z TO 15Z TIME FRAME...BUT CONFIDENCE IS LOW.
CEILINGS BECOMING MAINLY 2 TO 3 THSD FT BKN WITH LAYERS AND VSBY 5
TO 6 MILES IN HAZE AFTER ABOUT 16Z. YET...ADDITIONAL CLUSTERS OF
SHOWERS AND STORMS LIKELY...INTO THE EVENING HOURS...AGAIN WITH IFR
VSBY AND CEILINGS.
MVFR VSBY LIKELY 03Z TO 06Z SATURDAY WITH SHOWERS WANING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: DURATION AND TIMING ROUNDS OF CONVECTION WILL
VARY. AT LEAST SOME AREAS OF PCPN MAY EVEN LINGER LONGER FRIDAY
NIGHT...BUT NOT MENTIONED IN TAFS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY H H H M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M M M M
BKW CONSISTENCY M M M M H H H H H H M M
EKN CONSISTENCY H H H H H H M M H H M H
PKB CONSISTENCY L L L H H H H H M M M M
CKB CONSISTENCY M M M H H H H H H H M M
AFTER 12Z SATURDAY...
IFR CONDITIONS POSSIBLE IN LOW STRATUS IN LINGERING LOW LEVEL
MOISTURE 06Z TO AFTER 12Z SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
415 AM EDT FRI AUG 22 2014
.SYNOPSIS...
ROUNDS OF SHOWERS AND THUNDERSTORMS CONTINUE WITH OCCASIONAL
DOWNPOURS...AS WEAK DISTURBANCES RIDE SE. HIGH PRESSURE WILL TRY TO
NOSE IN FROM THE NORTHEAST EARLY NEXT WEEK AS UPPER RIDGE BUILDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
ENTERING INTO THE PEAK OF THE FLASH FLOOD CONCERN - NOW INTO TONIGHT.
BEST LOW LEVEL INFLOW AT 925 MB IS ONGOING WITH 20 TO 30 KNOT
UNDISTURBED FEED UP THE OHIO VALLEY AND INTO THE WNW TO ESE
BAROCLINIC ZONE. 925 MB REDUCES TO 10 TO 15 KNOTS AFTER 18Z TODAY.
SEVERAL SMALL MID LEVEL 500 MB VORT MAXIMUMS IN THE NW FLOW ALOFT.
ONE PASSES CROSSES SRN WV MOUNTAINS AROUND 12Z. 07Z RAP HAS ANOTHER
ALONG INDIANA/OHIO BORDER BY THEN. HOWEVER...EVEN AT 08Z...MORE
STORMS HAVE REACHED INTO WESTERN OHIO. SO...DOING HOURLY POPS WAS
CERTAINLY A CHALLENGE ON THIS GRAVEYARD SHIFT.
EVEN THOUGH THE PKB-CKB AREA DID NOT GET MUCH RAIN ON
THURSDAY...MOST COUNTIES HAVE BEEN AFFECTED PAST WEEK. DID NOT WANT
TO OVER FORECAST WHERE EACH CLUSTER OF STORMS MAY GO AND TRY TO
NARROW DOWN THE WATCH. POSTED A FLASH FLOOD WATCH FOR ENTIRE CWA
THROUGH 05Z SATURDAY. STILL SEEMS THE HEART OF THE CWA MOST
VULNERABLE. EVEN THE 07Z RAP HAS THE AXIS OF MAXIMUM PW FM NRN IL
ESE INTO CENTRAL WV AOA 2 INCHES. HOWEVER...THE SOUTHERN COAL
FIELDS HAVE BEEN THE WETTEST LATELY AND WOULD HAVE THE HIGHEST
RUNOFF PERCENTAGE.
STEERING FLOW TURNS MORE NORTH OVERNIGHT TONIGHT...SO PICTURING THE
TREND WILL BE FOR THE HIGHER POPS TO SINK INTO SOUTHERN COUNTIES
OVERNIGHT. THOUGH AS MENTIONED...LOW LEVEL INFLOW...AS
MENTIONED...NOT AS STRONG.
IN THIS PATTERN...COULD EVEN SEE STRONG RISES ON SOME HEADWATER
RIVERS TONIGHT INTO SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
BOUNDARY CONTINUES SINKING SOUTH SATURDAY...BUT STILL ENOUGH
MOISTURE AROUND TO KICK OFF SOME DIURNALLY DRIVEN SHOWERS AND
STORMS...MAINLY IN THE COAL FIELDS AND WV MOUNTAINS. PRECIP CHANCES
WILL GRADUALLY DECREASE NORTH TO SOUTH THROUGH THE
WEEKEND...EVENTUALLY DRYING OUT ACROSS THE NORTH AS HEIGHTS BUILD
AND A SURFACE HIGH NOSES IN FROM THE NE BY SUNDAY NIGHT.
DESPITE THE BOUNDARY HEADING SOUTH...STILL EXPECTING VERY WARM
TEMPERATURES. MADE ONLY MINIMAL CHANGES TO PREVIOUS HIGHS AND LOWS
BY BLENDING IN BIAS-CORRECTED CONSENSUS GUIDANCE.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
UPPER RIDGE CONTINUES TO BUILD INTO AREA BUT THE OPPRESSIVE HEAT
SHOULD STAY W OF THE AREA. HOWEVER...WE WILL STILL BE CONTENDING
WITH THE MUGGIES WITH TEMPS RUNNING NEAR NORMAL TO PERHAPS
SLIGHTLY ABOVE. A FRONT APPROACHES LONG ABOUT THURSDAY WITH
INCREASING CHANCES FOR SHRA/TSRA.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
ONE ROUNDS OF CONVECTION MOVES THROUGH 06Z TO 12Z WITH LOCALIZED
DOWNPOURS AND IFR VSBY AND CEILING. OTHER DISTURBANCES IN ITS WAKE
WILL RIDE SE AND MAY CAUSE ADDITIONAL CLUSTERS DURING THE
MORNING...FIGURING MORE IN SOUTHERN OHIO INTO WESTERN WEST VIRGINIA
FOR THE 12Z TO 15Z TIME FRAME...BUT CONFIDENCE IS LOW.
CEILINGS BECOMING MAINLY 2 TO 3 THSD FT BKN WITH LAYERS AND VSBY 5
TO 6 MILES IN HAZE AFTER ABOUT 16Z. YET...ADDITIONAL CLUSTERS OF
SHOWERS AND STORMS LIKELY...INTO THE EVENING HOURS...AGAIN WITH IFR
VSBY AND CEILINGS.
MVFR VSBY LIKELY 03Z TO 06Z SATURDAY WITH SHOWERS WANING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: DURATION AND TIMING ROUNDS OF CONVECTION WILL
VARY. AT LEAST SOME AREAS OF PCPN MAY EVEN LINGER LONGER FRIDAY
NIGHT...BUT NOT MENTIONED IN TAFS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 08/22/14
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H H M M M H H M M M M M
HTS CONSISTENCY L M M H H M M M M M M M
BKW CONSISTENCY M M M M M M M H H H M M
EKN CONSISTENCY H H M H H H H H H H H H
PKB CONSISTENCY M M M M M L H H H M H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 06Z SATURDAY...
IFR CONDITIONS POSSIBLE IN LOW STRATUS IN LINGERING LOW LEVEL
MOISTURE 06Z TO AFTER 12Z SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
627 AM CDT FRI AUG 22 2014
.AVIATION...
SIMILAR TO THE PAST FEW DAYS...THUNDERSTORMS WILL LIKELY DEVELOP
WEST OF KLBB LATE THIS AFTERNOON INTO THE EVENING.
HOWEVER...CONFIDENCE IS NOT HIGH IN STORMS REACHING THE KLBB
TERMINAL AND WILL LEAVE ANY MENTION OF THUNDER OUT UNTIL BETTER
CONFIDENCE CAN BE ACHIEVED.
&&
.PREV DISCUSSION... /ISSUED 421 AM CDT FRI AUG 22 2014/
SHORT TERM...
AFTERNOON AND EVENING THUNDERSTORM CHANCES WILL LIVE ANOTHER DAY. A
CLOSED LOW CURRENTLY OVER ARIZONA WILL OPEN UP AS IT MOVES ACROSS
THE ROCKIES AS A SHORT WAVE TROUGH. HOWEVER...IT REMAINS
QUESTIONABLE ON WHETHER WE WILL BENEFIT FROM THIS TROUGH AS ITS JET
MAX WILL BE PLACED WELL NORTH AND WEST OF THE REGION. WE STILL STILL
LIKELY SEE ISOLATED TO SCATTERED CONVECTION UNDERNEATH A MONSOONAL
MOISTURE PLUME CAUGHT BETWEEN THE TROUGH TO THE WEST AND RIDGE TO
THE EAST. CONVENTION WILL BE WITHIN THE SURFACE PRESSURE TROUGH AND
THE RAP INDICATES A FARTHER EASTWARD MOVEMENT TO THE TROUGH AXIS.
LOW LEVEL CONVERGENCE MAY BE MORE TO THE EAST IF THE RAP IS MORE
CORRECT IN ITS SOLUTION ALLOWING FOR CONVECTION TO DEVELOP FARTHER
EAST ON THE CAPROCK.
A NOTABLE DECREASE IN PRECIPITABLE WATER VALUES WILL OCCUR TODAY
MOSTLY FOR AREAS EAST OF THE I27 CORRIDOR. THIS WILL BE DUE TO DRIER
AIR ADVECTING INTO THE AREA AT MID LEVELS. THERE WILL NOT BE MUCH
CHANGE FOR AREAS WEST OF I27 WITH CONTINUED ANOMALOUSLY HIGH
PRECIPITABLE WATER VALUES. AN AXIS OF HIGHER INSTABILITY IS PROGGED
TO BE AROUND 2000 J/KG WITHIN THE PRESSURE TROUGH WHERE THE HIGHEST
LOW LEVEL THETA-E AIR WILL BE LOCATED. FURTHERMORE...STORM
PROPAGATION VECTORS TO THE SOUTHWEST WILL LEAD TO POSSIBLE TRAINING
OF CONVECTION AND REPEATED HEAVY RAINFALL DESPITE RELATIVELY HIGH
CLOUD BASES.
LONG TERM...
A THINNING BAND OF MONSOONAL MOISTURE WILL CONTINUE ACROSS THE
AREA OVER THE WEEKEND AS AN UPPER TROUGH SKIRTS BY TO THE NORTH.
LIMITED IF ANY SIGNIFICANT LIFT IS EXPECTED THOUGH MODEST SURFACE
TROUGHING AND STRONG HEATING MAY CONTRIBUTE TO A FEW AFTERNOON
STORMS IN AND NEAR THAT TROUGH. HEIGHTS WILL REBUILD EARLY NEXT
WEEK WITH THE MONSOON FLOW IMPROVING AGAIN...THOUGH SHIFTING BACK
TO THE WEST. UNCLEAR JUST YET IF THIS WILL REMAIN NEAR ENOUGH OUR
WESTERN BORDER AREAS FOR MENTIONABLE THUNDER CHANCES. UNCERTAINTY
INCREASES THE MIDDLE OF NEXT WEEK INVOLVING THE NEXT PROGRESSIVE
PACIFIC TROUGH CROSSING THE NORTHERN TIER. BOTH AMPLITUDE AND
TIMING ARE MUCH IN QUESTION...THUS PRECLUDING THUNDER MENTION AS
WELL FOR NOW. BUT THIS MAY YET REPRESENT OUR NEXT REAL OPPORTUNITY
FOR THUNDERSTORMS AS A FRONTAL BOUNDARY THAT HAS BEEN HANGING
ACROSS NORTHERN STATES COULD SAG INTO OUR AREA. IN THE DAYS AHEAD
WE WILL WATCH FOR THOSE TIMING AND STRENGTH ISSUES TO BECOME
BETTER RESOLVED. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 64 93 62 92 / 30 40 20 20 20
TULIA 94 65 95 65 93 / 20 20 20 20 20
PLAINVIEW 93 65 94 65 92 / 20 20 20 20 20
LEVELLAND 94 64 93 64 92 / 20 20 20 20 20
LUBBOCK 95 67 96 67 94 / 20 20 20 20 20
DENVER CITY 94 65 94 65 93 / 20 20 10 10 10
BROWNFIELD 95 65 95 66 94 / 20 20 10 10 10
CHILDRESS 100 70 100 72 99 / 10 10 10 10 10
SPUR 97 68 97 67 96 / 10 10 10 10 10
ASPERMONT 99 71 100 71 99 / 0 0 10 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
421 AM CDT FRI AUG 22 2014
.SHORT TERM...
AFTERNOON AND EVENING THUNDERSTORM CHANCES WILL LIVE ANOTHER DAY. A
CLOSED LOW CURRENTLY OVER ARIZONA WILL OPEN UP AS IT MOVES ACROSS
THE ROCKIES AS A SHORT WAVE TROUGH. HOWEVER...IT REMAINS
QUESTIONABLE ON WHETHER WE WILL BENEFIT FROM THIS TROUGH AS ITS JET
MAX WILL BE PLACED WELL NORTH AND WEST OF THE REGION. WE STILL STILL
LIKELY SEE ISOLATED TO SCATTERED CONVECTION UNDERNEATH A MONSOONAL
MOISTURE PLUME CAUGHT BETWEEN THE TROUGH TO THE WEST AND RIDGE TO
THE EAST. CONVENTION WILL BE WITHIN THE SURFACE PRESSURE TROUGH AND
THE RAP INDICATES A FARTHER EASTWARD MOVEMENT TO THE TROUGH AXIS.
LOW LEVEL CONVERGENCE MAY BE MORE TO THE EAST IF THE RAP IS MORE
CORRECT IN ITS SOLUTION ALLOWING FOR CONVECTION TO DEVELOP FARTHER
EAST ON THE CAPROCK.
A NOTABLE DECREASE IN PRECIPITABLE WATER VALUES WILL OCCUR TODAY
MOSTLY FOR AREAS EAST OF THE I27 CORRIDOR. THIS WILL BE DUE TO DRIER
AIR ADVECTING INTO THE AREA AT MID LEVELS. THERE WILL NOT BE MUCH
CHANGE FOR AREAS WEST OF I27 WITH CONTINUED ANOMALOUSLY HIGH
PRECIPITABLE WATER VALUES. AN AXIS OF HIGHER INSTABILITY IS PROGGED
TO BE AROUND 2000 J/KG WITHIN THE PRESSURE TROUGH WHERE THE HIGHEST
LOW LEVEL THETA-E AIR WILL BE LOCATED. FURTHERMORE...STORM
PROPAGATION VECTORS TO THE SOUTHWEST WILL LEAD TO POSSIBLE TRAINING
OF CONVECTION AND REPEATED HEAVY RAINFALL DESPITE RELATIVELY HIGH
CLOUD BASES.
&&
.LONG TERM...
A THINNING BAND OF MONSOONAL MOISTURE WILL CONTINUE ACROSS THE
AREA OVER THE WEEKEND AS AN UPPER TROUGH SKIRTS BY TO THE NORTH.
LIMITED IF ANY SIGNIFICANT LIFT IS EXPECTED THOUGH MODEST SURFACE
TROUGHING AND STRONG HEATING MAY CONTRIBUTE TO A FEW AFTERNOON
STORMS IN AND NEAR THAT TROUGH. HEIGHTS WILL REBUILD EARLY NEXT
WEEK WITH THE MONSOON FLOW IMPROVING AGAIN...THOUGH SHIFTING BACK
TO THE WEST. UNCLEAR JUST YET IF THIS WILL REMAIN NEAR ENOUGH OUR
WESTERN BORDER AREAS FOR MENTIONABLE THUNDER CHANCES. UNCERTAINTY
INCREASES THE MIDDLE OF NEXT WEEK INVOLVING THE NEXT PROGRESSIVE
PACIFIC TROUGH CROSSING THE NORTHERN TIER. BOTH AMPLITUDE AND
TIMING ARE MUCH IN QUESTION...THUS PRECLUDING THUNDER MENTION AS
WELL FOR NOW. BUT THIS MAY YET REPRESENT OUR NEXT REAL OPPORTUNITY
FOR THUNDERSTORMS AS A FRONTAL BOUNDARY THAT HAS BEEN HANGING
ACROSS NORTHERN STATES COULD SAG INTO OUR AREA. IN THE DAYS AHEAD
WE WILL WATCH FOR THOSE TIMING AND STRENGTH ISSUES TO BECOME
BETTER RESOLVED. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 64 93 62 92 / 30 40 20 20 20
TULIA 94 65 95 65 93 / 20 20 20 20 20
PLAINVIEW 93 65 94 65 92 / 20 20 20 20 20
LEVELLAND 94 64 93 64 92 / 20 20 20 20 20
LUBBOCK 95 67 96 67 94 / 20 20 20 20 20
DENVER CITY 94 65 94 65 93 / 20 20 10 10 10
BROWNFIELD 95 65 95 66 94 / 20 20 10 10 10
CHILDRESS 100 70 100 72 99 / 10 10 10 10 10
SPUR 97 68 97 67 96 / 10 10 10 10 10
ASPERMONT 99 71 100 71 99 / 0 0 10 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01/05
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1024 PM EDT SAT AUG 23 2014
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES TONIGHT AND
SUNDAY TO WEDGE AGAINST THE EASTERN FACE OF THE APPALACHIANS. THIS
HIGH PRESSURE SYSTEM WILL BRING COOLER AND MUCH DRIER AIR TO THE
MID ATLANTIC THROUGH MID WEEK. ANOTHER COLD FRONT WILL APPROACH
THE AREA LATE IN THE WORKWEEK...BRINGING ANOTHER CHANCE OF SHOWERS
AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1015 PM EDT SATURDAY...
COVERAGE OF SHOWERS ATTM IS LIMITED...AND MAINLY ISOLATED/WIDELY
SCATTERED. BEST COVERAGE REMAINS ALONG EASTERN SLOPES OF THE BLUE
RIDGE FROM BEDFORD SOUTHWEST TO JUST EAST OF WILKESBORO. THE
LATEST HRRR AND THE RUN FROM 22Z ACTUALLY DID A PRETTY GOOD JOB OF
LINING THIS UP THIS EVENING. THE 00Z NAM/12Z ECMWF APPEAR TOO
BULLISH WITH QPF AND MAY BE SUFFERING FROM CONVECTIVE FEEDBACK AS
THEY CONTINUE TO SHOW 3/4 TO 1.5 INCHES ACROSS PORTIONS OF THE
BLUE RIDGE OVERNIGHT. NOT THAT 3/4" COULD NOT OCCUR...BUT OVERALL
CONVECTIVE TRENDS ARE WEAKER...SO NOT REALLY SEEING ANYTHING MORE
THAN A QUICK QUARTER INCH IN A FEW SPOTS.
FORECAST FAVORS THE HRRR AND WILL KEEP HIGHER THREAT OF SHOWERS
ACROSS THE SRN BLUE RIDGE INTO THE OVERNIGHT WITH LESS COVERAGE
FAR SW VA/SE WV AND OVER THE FAR ERN PIEDMONT.
WEDGE ALREADY TAKING SHAPE PER MESOANALYSIS OF SFC LI FIELDS. LOW
IR SAT ALSO SHOWING EXTENSIVE AREA OF LOWER CIGS MOVING IN FROM
THE NE...AS FAR SW AS THE NEW RIVER VALLEY. WILL SEE CLOUDS
OVERSPREAD THE REST OF THE CWA OVERNIGHT THOUGH THE FAR SW VA AREA
MAY SEE LESS CLOUD COVER. TEMPS WILL STAY UP DUE TO THE CLOUDS IN
THE MID 60S TO LOW 70S.
PREVIOUS VALID DISCUSSION...
SHOWER ACTIVITY WILL BE MORE DIMINISHED ON SUNDAY AS HIGH
PRESSURE CONTINUES TO BUILD IN...CAUSING OUR ATMOSPHERE TO DRY
OUT. BEST CHANCES FOR ANY RAINFALL WILL BE EARLY IN THE DAY...WITH
SHOWERS BECOMING INCREASINGLY ISOLATED DURING THE EVENING FROM
SOUTHWEST TO NORTHEAST. WILL ALSO EXPECT DECREASING CLOUD COVER
DURING THE AFTERNOON AND EVENING AS WELL. HIGH PRESSURE SETTLING
IN WILL RESULT IN COOLER AFTERNOON HIGHS...RANGING FROM THE MID
70S ALONG THE RIDGES TO AROUND 80 ACROSS THE SOUTHSIDE.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 245 PM EDT SATURDAY...
STRONG WEDGE OF HIGH PRESSURE WILL BE OVER THE FORECAST AREA THROUGH
THE PERIOD.
DEEP ENOUGH LAYER OF NORTHEAST WINDS TO BRING A PUSH OF DRIER AIR
INTO THE FORECAST AREA ABOVE 850 MB SUNDAY NIGHT. HOW FAST THE AIR
MASS BELOW 850 MB DRIES OUT WILL BE CRITICAL TO THE EROSION OF LOW
CLOUDS AND ANY LINGERING DRIZZLE AND FOG. BUFKIT SOUNDING SHOW THE
FAR SOUTHWEST PART OF THE COUNTY WARNING AREA MAY NOT BREAK OUT OF
THE CLOUDS UNTIL AFTER 12Z MONDAY. BY MONDAY NIGHT PRECIPITABLE
WATER VALUES DROP BELOW AN INCH FOR THE ENTIRE FORECAST AREA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 1145 AM EDT SATURDAY...
ANOTHER UPPER TROF WILL LOWER HEIGHTS MORE OVER THE CENTRAL AND
NORTHERN UNITED STATES WEDNESDAY THROUGH SATURDAY WITH THE UPPER
RIDGE CENTERED OFF THE SOUTHEAST COAST.
AT THE SURFACE HIGH PRESSURE WILL BE OVER THE REGION THROUGH
WEDNESDAY. A FRONT WILL EXTEND FROM A LOW OVER THE MID MISSISSIPPI
VALLEY ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES.
SOUTHWARD PROGRESS OF THIS BOUNDARY WILL BE SLOW. ECMWF AND WPC
GUIDANCE KEEP THIS FRONT NORTH OF THE FORECAST AREA THROUGH FRIDAY.
HAVE TRIMMED BACK THE PROBABILITY OF PRECIPITATION THURSDAY AND
FRIDAY WITH THE FORECAST AREA IN THE WARM SECTOR. A BETTER...MORE
ORGANIZED...CHANCE OF PRECIPITATION WILL BE DURING THE WEEKEND WHEN
THE UPPER TROF AND SURFACE COLD FRONT ARRIVE FROM THE WEST.
EXPECTING GRADUALLY MODERATING TEMPERATURES WEDNESDAY AND THURSDAY.
850 MB TEMPERATURES BY 00Z FRIDAY WILL BE BACK UP IN THE +16 TO +20
RANGE. THIS WILL RESULT IN MAXIMUM TEMPERATURES SLIGHTLY ABOVE
NORMAL.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
AS OF 720 PM EDT SATURDAY...
SHOWER ACTIVITY IS CONCENTRATED NEAR ROA/BCB AND EAST. ALSO
ISOLATED SHRA NEAR LWB. NEAR TERM TAFS SHOW A VCSH OR
-SHRA...EXCEPT BLF. LOOKING AT WEDGE FRONT TO MOVE WEST THIS
EVENING WITH SHOWERS SHIFTING SWWD TOWARD SW VA/NW NC...AND CIGS
SINKING TO MVFR THEN IFR/LIFR OVERNIGHT INTO EARLY SUNDAY MORNING.
MODEL SOUNDING FORECAST SUGGEST THAT DRIZZLE APPEARS LIKELY AT
MOST TAF SITES LATE TONIGHT. AT THIS TIME...VSBYS SHOULD STAY
ABOVE 1SM...MORE IN THE 2 TO 6 MILE RANGE WHILE CIGS DROP TO UNDER
1KFT.
CIGS WILL BE SLOW TO LIFT SUNDAY MORNING BUT THINK BY LATE
MORNING/MIDDAY WILL SEE MAINLY HIGH END MVFR AT ALL SITES...EXCEPT
VFR AT BLF JUST OUTSIDE THE INFLUENCE OF THE WEDGE.
COULD SEE A FEW SHOWERS/LIGHT RAIN INTO MIDDAY SUNDAY BY NOT
ENOUGH COVERAGE TO ADD TO THE TERMINALS AT THIS TIME.
ANY SHOWERS WILL BEGIN TO WANE SUNDAY AFTERNOON AS HIGH PRESSURE
CONTINUES TO WEDGE INTO THE REGION...BECOMING THE DOMINANT WEATHER
FEATURE.
THIS HIGH PRESSURE STRETCHING FROM NEW ENGLAND SOUTHWARD ALONG
THE EASTERN FACE OF THE APPALACHIANS WILL MAINTAIN DRY CONDITIONS
THROUGH THE EARLY HALF OF THE WORKWEEK. LONG RANGE MODELS INDICATE
THAT A POTENTIAL TROPICAL CYCLONE DEVELOPING NEAR THE BAHAMAS
SHOULD REMAIN OFF THE EAST COAST AND NOT IMPACT THE LOCAL WEATHER.
A COLD FRONT WILL SINK SOUTHWARD FROM THE GREAT LAKES ON
THURSDAY...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS AS WELL
AS MVFR/IFR CONDITIONS.
&&
.EQUIPMENT...
AS OF 700 PM SATURDAY...
THE ASOS TEMPERATURE AT LYNCHBURG (LYH) VA REMAINS INOP DUE TO A
BOARD FAILURE. TECHNICIANS ARE EXPECTED TO WORK ON THIS MONDAY. TOWER
OBSERVERS ARE AUGMENTING DURING NORMAL SERVICE HOURS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...NF/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...NF/RAB/WP
EQUIPMENT...WP
AREA FORECAST DISCUSSION
NWS SEATTLE WA
905 AM PDT FRI AUG 22 2014
.SYNOPSIS...AN UNSTABLE AIR MASS ASSOCIATED WITH AN UPPER LOW OVER
THE INTERIOR OF THE PACIFIC NORTHWEST WILL GENERATE AND CIRCULATE A
FEW SHOWERS AND LATE DAY THUNDERSTORMS OVER THE CASCADES TODAY.
OTHERWISE HIGHER PRESSURE ALOFT WILL NOSE INTO THE REGION THIS
WEEKEND FOR MORE SUNSHINE AND WARMER DAYTIME TEMPERATURES. THIS
WARMING TREND IS EXPECTED TO CONTINUE INTO THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...IN THE BIG PICTURE THE UPPER RIDGE IS NOW NEAR 140W
WITH THE UPSTREAM UPPER TROUGH NEAR THE DATELINE. THE SHORTWAVE THAT
WAS DIGGING DOWN THE EAST SIDE OF THE UPPER RIDGE HAS NOW SLID SE
INTO THE PACIFIC NW INTERIOR. RAOBS AT KUIL, KOTX AND KSLE THIS
MORNING SHOW THE AIR MASS IS QUITE UNSTABLE. SO THE CONTINUED THREAT
OF CONVECTION OVER THE CASCADES LATER TODAY LOOKS ON TRACK. THE BULK
OF CONVECTION SHOULD BE EAST OF THE CASCADES THOUGH.
LOW LEVEL ONSHORE FLOW CONTINUES THIS MORNING THOUGH WEAKER THAN
THURSDAY. THE MORE UNSTABLE AIR MASS RESULTED IN MORE LIMITED MARINE
CLOUDS IN WESTERN WA THIS MORNING. TOPS ARE SHALLOW - NO MORE THAN
1500 FT. SO THE CLOUDS AND FOG SHOULD DISSIPATE BY MIDDAY. TODAY
WILL MARK THE GRADUAL REBOUND OF DAYTIME TEMPERATURES WITH MORE
SUNSHINE AND A WARMER AIR MASS.
THE 12Z PROGS IN THUS FAR CONTINUE THE TREND OF NOSING IN HIGHER
PRESSURE ALOFT AS THE UPPER LOW CONTINUES FURTHER INLAND AND HEIGHTS
ALOFT RISE. ANOTHER VERY WEAK SHORTWAVE IS SET TO SLIDE SE INTO THE
NORTHERN ROCKIES SUNDAY IN THE NW FLOW ALOFT. THE PRIMARY IMPACT
SHOULD BE TO SLOW THE WARM UP AND KEEP LOW LEVEL ONSHORE FLOW GOING.
NO UPDATES TO THE FORECAST PACKAGE THOUGH DID MASSAGE THE SKY GRIDS
A BIT FOR TODAY AND THIS EVENING. BUEHNER
.LONG TERM...FROM THE PREVIOUS DISCUSSION...AN UPPER RIDGE WILL
PREVAIL OVER THE REGION DURING THIS PERIOD...HOWEVER IT WILL
GRADUALLY WEAKEN WITH TIME. IN FACT...THE LATEST GFS SOLUTION SHOWED
AN UPPER TROF OVER THE PACIFIC NORTHWEST ON DAY 7. THE INHERITED
FORECAST SHOWED TEMPS COOLING OFF LATE IN THE PERIOD AND THAT LOOKS
FINE. NC
&&
.AVIATION...A WEAK UPPER LEVEL TROUGH OVER THE AREA THIS MORNING
WILL SHIFT SOUTHEAST INTO SOUTHERN IDAHO BY SATURDAY MORNING. LIGHT
NORTHERLY FLOW ALOFT WILL BECOME NORTHWESTERLY AS THE LOW MOVES
SOUTHEAST. LOW LEVEL FLOW WILL REMAIN ONSHORE AND WEAK.
MARINE STRATUS THAT FORMED THIS MORNING OVER THE COAST...SOUTHWEST
INTERIOR...STRAIT AND WESTERN SKAGIT/SNOHOMISH COUNTIES REMAINS
SHALLOW WITH CEILINGS BELOW 1000 FEET AND LOCAL VISIBILITIES BELOW A
MILE. LIGHT NORTHERLY SURFACE GRADIENTS HELPED LIMIT THE EXTENT OF
THE LOW CLOUDS OVER THE INTERIOR...WITH MUCH OF THE CENTRAL SOUND
AND WESTERN WHATCOM COUNTY REMAINING CLEAR. THOSE AREAS WITH LOW
CLOUDS AND FOG WILL SEE CEILINGS AND CONDITIONS IMPROVE THROUGH THE
MORNING...SCATTERING OUT OVER THE INTERIOR BY 18Z/11 AM AND THE
COAST BY 20Z/1 PM. WARMING AND WITH THE NORTHERLY FLOW BOTH ALOFT
AND AT LOW LEVELS TODAY WILL MAKE IT MORE DIFFICULT FOR LOW CLOUDS
AND OR STRATUS TO REFORM OVER THE INTERIOR SATURDAY MORNING.
KSEA...MOSTLY CLEAR SKIES TODAY WITH VFR CONDITIONS PERSISTING
THROUGH SATURDAY. LIGHT WINDS WILL BECOME NORTHWESTERLY 4 TO 8 KNOTS
BY EARLY AFTERNOON AND PERSIST THROUGH THE EVENING...THEN BECOME
LIGHT AND NORTHEASTERLY AFTER 06Z/11 PM.
&&
.MARINE...THE VERY PERSISTENT ONSHORE FLOW PATTERN WILL CONTINUE FOR
THE NEXT SEVERAL DAYS. THE STRENGTH OF THE ONSHORE FLOW WILL VARY
DIURNALLY. EXPECT THE STRONGEST WESTERLY WINDS IN THE CENTRAL AND
EASTERN STRAIT DURING THE EVENING AND EARLY MORNING HOURS WITH SMALL
CRAFT ADVISORIES POSSIBLE AT THAT TIME EACH DAY INTO THE FIRST PART
OF NEXT WEEK. OVER THE COASTAL WATERS SURFACE HIGH PRESSURE BUILDING
INSIDE OF 140 W WILL TIGHTEN UP SURFACE GRADIENTS SATURDAY EVENING
OVER THE OUTER COASTAL WATERS...BOOSTING THE NORTHWESTERLIES ABOVE
SMALL CRAFT CRITERIA. WEST TO NORTHWESTERLY SWELL 4 TO 5 FEET WITH A
PERIOD AROUND 8 SECONDS WILL PERSIST THROUGH THE WEEKEND.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT OF JUAN DE FUCA
TONIGHT.
&&
$$
WWW.WEATHER.GOV/SEATTLE/
FOR THE GRAPHICAL AFD...VISIT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
Area Forecast Discussion
National Weather Service Spokane WA
536 AM PDT FRI AUG 22 2014
.SYNOPSIS...
Friday will bring another round of showers and thunderstorms to
the region with the potential for more flash flooding over the
Cascades burn scars. The threat of scattered showers and
thunderstorms will continue through the weekend. A drier and
warmer weather pattern is expected for the new work week.
&&
.DISCUSSION...
Friday: A deep upper-level low pressure system will pass through the
region today delivering widely scattered showers and thunderstorms.
Storms containing heavy rainfall and very little movement will be
the main concern as the risk for flash flooding and debris flows
remains elevated over the East Slopes and Okanogan Highlands.
Additional urban and rural areas could also experience localized
flooding impacts if a storm was to setup overhead. An isolated
stronger storm could also bring brief hail and gusty outflow
winds on the order of 40 mph.
2AM satellite reveals the center of the low crossing over the
Columbia Gorge near the Dalles. The low will shift east toward
the Tri Cities this morning...then continue toward the OR/WA/ID
border by midday before tracking into SE Idaho this evening. With
the low overhead, an unstable air mass will be in place with
500mb temperatures cooling near -17C. Meanwhile, a tongue of
richer moisture and instability...marked well by the 850-700mb
theta-e progs will wrap around the eastern and northern periphery
of the low...wrapping back south on its western edge. This richer
moisture in conjunction with little to no steering flow is a good
recipe for storms containing heavy rainfall. The good news is that
this lack of steering flow (storm movement) only resides through
late afternoon then as the system departs the east, increasing
northerly flow will give any lingering storms a push. Needless to
say, we saw what these storms are capable of Thursday afternoon
with numerous debris flows and mudslides within the Carlton
Complex burn scar.
As of 2AM...thunderstorms continue to go strong across the
northern mountains with additional development now over the lower
ID Panhandle. This activity is tied to the placement of the higher
theta-E axis and lift along the northeastern periphery of the
upper low dropping into the Pac NW. HRRR and local Hi-Res model
simulated radar suggest the larger area of showers/storms over
Ferry County will pivot to the west this morning, fall apart after
sunrise, allowing cells to redevelop after a few hours of
sunshine. Convective temperatures are only in the upper 60`s to
lower 70`s so it won`t take much. Whether the cloud cover from
this activity completely falls apart or just thins will be a major
challenge related to storm intensity this afternoon. For NE WA and
the ID panhandle, looks as if isolated storms will be possible
through morning then afternoon heating and a few vorticity
maximums will promote widely scattered storms again after the
12PM-3PM timeframe...continuing through the evening. Slightly
deeper wind shear over the lower ID Panhandle could support a few
organized cells capable of hail and wind gusts in excess of 40 mph
but overall, the threat for severe storms (hail and damaging
winds) remains low region-wide.
Saturday: The upper-low will continue its march east Friday night
and Saturday into Central Montana Saturday morning then North
Dakota by the evening. Look for drier north to northwest flow over
the Cascades and Western Basin Saturday morning to translate east
into the Idaho Panhandle by Saturday evening. The main
precipitation threat will concentrate over the ID Panhandle and
into Western Montana. Some models are more aggressive with the
drying so we may be on the high end for precipitation chances in
Idaho, especially west of a line from Mullan to the Blue Mtns.
Given the lingering cold pool aloft, a few convective showers will
be possible in the mountains all the way to the Cascade Crest but
these will be the weak and shallow variety producing little to no
rainfall.
We will also see breezy northerly winds as the low deepens today
then pulls out Saturday. Winds will be strongest through the
narrow Okanogan Valley and Purcell Trench. Winds sustained 10-20
mph with gusts to 35 mph are a strong possibility. Temperatures
will remain on the cool side of normal. /sb
Saturday night through Wednesday...General agreement exists
between the latest medium range models with the overall field of
motion. The general troffy and unsettled pattern will persist
through Sunday featuring a continued threat of showers and at
least isolated thunderstorms mainly during the afternoon and
evening hours and concentrated over the northern mountains...with
a few showers persisting well into the night over the Idaho
Panhandle. Temperatures in this polar influenced air mass will run
at or slightly below normal through Monday.
Monday appears to bring a transition from a general trough to a
new ridging cycle...with only a few lingering showers over the
northeast and panhandle while the remainder of the forecast area
dries out and stabilizes under the ridge driven warming aloft.
Tuesday through Wednesday bring high confidence of dry and
clear/partly cloudy conditions throughout the region as the polar
storm track retreats to the north with temperatures once again
cresting well above normal. /Fugazzi
Wednesday Evening through Thursday Night: Starting Wednesday
evening the strength of the ridge will be on the decline as the
next trough of low pressure approaches the region. Models are
still wavering a bit on the breakdown, but one thing in common for
now is Wednesday will be the warmest day of the forecast period.
Considering model differences for the breakdown, the GFS continues
to be much more aggressive bringing a deep trough swinging
through late Thursday. This solution would support another round
of widespread rain as the system would have both mid latitude
Pacific moisture as well as topical moisture from decaying
Tropical Storm Lowell to work with. The euro on the other hand
keeps the trough further north leading to a much drier zonal flow
pattern for the Pac NW. Either way, we are looking at breezy to
windy conditions for the later part of the week as cold air
advection coupled with a tightened pressure gradient increases the
winds. Both models have been fairly consistent in their respective
solutions, so the DGEX was used to help lean in one models favor.
It more closely followed the Euro leading to higher confidence in
it.
So leaning towards the euro, it delays the major threat of precip
beyond the reaches of this forecast so POPs were kept relatively low.
Temperatures were also raised a bit Thursday to show the
transition to a more zonal pattern rather than the cold incoming
trough from the GFS. One thing to keep in mind is that when models
try to ingest this tropical storm moisture, it often leads to some
inconsistent runs. Knowing this, the extended will need to be
tinkered with throughout the next couple of days as models align
better. /Fliehman
&&
.AVIATION...
12Z TAFS: Broad area of low pressure aloft will promote widely
scattered showers and thunderstorms through 03z. Every terminal
will stand a threat for storms, especially after 22z. Ongoing
thunderstorms this morning in vcnty KPUW/KLWS are expected to
track north by 15z with a brief break before afternoon heating
promotes more storms aft 22z. Winds will generally be out of the
north/northeast...locally gusty through the Okanogan Valley and
Purcell Trench impacting Omak...Sandpoint...and Couer D Alene
airports. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 75 55 75 54 79 56 / 40 40 10 10 20 30
Coeur d`Alene 73 54 73 51 77 53 / 50 50 10 10 20 30
Pullman 75 51 74 49 79 51 / 40 50 20 20 20 20
Lewiston 80 60 79 56 85 59 / 60 50 30 20 10 20
Colville 72 51 78 49 81 52 / 60 50 10 10 20 30
Sandpoint 69 50 71 46 75 49 / 70 50 10 20 20 30
Kellogg 68 52 67 47 72 53 / 70 60 40 20 30 30
Moses Lake 81 58 83 56 86 58 / 30 50 10 0 10 10
Wenatchee 80 63 82 58 84 64 / 40 50 10 10 20 10
Omak 79 59 82 53 85 58 / 50 40 10 10 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch through this evening for East Slopes Northern
Cascades-Okanogan Valley-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
330 AM PDT FRI AUG 22 2014
.SYNOPSIS...UPPER LEVEL LOW PRESSURE CENTER CONTINUES TO SLIDE EAST OF
THE AREA TODAY. THERE WILL BE ENOUGH INSTABILITY ON THE WEST SIDE OF
THIS LOW TO BRING A THUNDERSTORM THREAT MAINLY TO THE SOUTH
WASHINGTON CASCADES AND...TO A LESSER EXTENT...THE FAR NORTH OREGON
CASCADES AS WELL. MAY GET SOME SHOWERS FURTHER WEST ACROSS THE
NORTHERN FORECAST AREA ALTHOUGH HAVE WAVERING CONFIDENCE. NORTHERLY
FLOW ALOFT CONTINUES OVER THE WEEKEND MAINTAINING ONSHORE LOW-LEVEL
FLOW AND NEAR TO SLIGHTLY ABOVE NORMAL HIGH TEMPERATURES. HIGH
PRESSURE STRENGTHENS JUST OFFSHORE BRINGING A WARM UP FOR
THE FIRST HALF OF NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH SUNDAY...LOW PRESSURE WILL CONTINUE TO
DEVELOP ACROSS THE INTERIOR PACNW TODAY RESULTING IN A CHALLENGING
FORECAST FOR THE NEXT 24 HOURS. A CLOSED LOW CENTER IS BEGINNING TO
WIND UP UNDER CYCLOGENESIS. THE COMPLEX DYNAMICS WITH THE DEVELOPING
LOW WERE ABLE TO WRING OUT SOME DRIZZLE ALONG THE COAST WITH BOTH
ASTORIA AND NEWPORT RECORDING AT LEAST AN HOUR OF PRECIPITATION.
NORTH ANS EAST OF THE DEVELOPING LOW CENTER...A SIGNIFICANT AMOUNT
OF NOCTURNAL CONVECTION THUS FAR HAS GENERATED MOISTURE WHICH WILL
GET WRAPPED AROUND TO MOISTEN UP THE WESTERN FRINGES OF THE LOW.
EXPECT THE NORTHEASTERN 1/3RD OF THE CWA WILL BE IMPACTED BY THIS
MOISTURE IN VARYING FORMS.
THE MOST SIGNIFICANT THREAT WILL BE FOR THUNDERSTORMS. STILL FEEL
MOST ACTIVITY WILL REMAIN CONFINED TO AREAS NORTHEAST OF THE
PORTLAND METRO AND CLOSER TO MT ADAMS. BOTH THE NAM AND GFS AGREE
THERE WILL BE SUFFICIENT SURFACE HEATING AND MOISTURE TO CREATE DEEP
CONVECTION AND THUNDERSTORMS. FURTHER SOUTH AND WEST THE MODELS HAVE
LIMITED AGREEMENT. THE BIG ISSUE WILL BE SURFACE DEW POINTS. THE NAM
AS OF THE LAST FEW YEARS HAS COMMONLY PRODUCE TOO MUCH SURFACE
MOISTURE AND THUS DEW POINTS TOO HIGH BY A FEW DEGREES.
CONVERSELY...THE GFS TENDS TO RUN A FEW DEGREES TO DRY. THE 00Z MODEL
RUNS ARE HOLDING TRUE TO EXPECTATIONS AT LEAST THROUGH THE 09Z HOUR
WITH REALITY LYING SOMEWHERE IN BETWEEN BUT A SLIGHT BIT CLOSER TO
THE GFS. DETERMINING WHAT REALITY WILL BRING IS WHERE THE SPECIFIC
CHALLENGE LIES. SKIN TEMPERATURES FROM BOTH MODEL FORECAST SOUNDINGS
ARE ALSO APPEARING TO BE TOO COOL AS IS OFTEN THE CASE. BASED ON
THE RAW MODEL SOUNDING DATA...THE GFS DOES NOT SHOW CONVECTION VERY
FAR AWAY FROM THE CASCADES WHILE THE NAM BRINGS A THREAT TO THE
METRO AND AS FAR WEST AS ABOUT KELSO/LONGVIEW. ULTIMATELY LANDED ON
ABOUT A 60/40 BLEND OF SURFACE DEW POINTS FAVORING THE GFS. THIS
COMBINED WITH MANUAL TEMPERATURE ADJUSTMENTS TO THE SOUNDING SURFACE
CONDITIONS PRODUCED A FIRST ESTIMATE OF THUNDERSTORMS WITH
CONFIDENCE AND ISOLATED COVERAGE ACROSS THE BULK OF SKAMANIA
COUNTY...LOWER CONFIDENCE SLIGHT CHANCE COVERAGE TO THE EASTERN 1/4
OF COWLITZ COUNTY STRETCHING SOUTH TO INCLUDE THE GORGE AND AREAS
EAST OF SANDY AROUND MT HOOD...AND THEN A THREAT OF SHOWERS ONLY
MAINLY NORTH OF THE COLUMBIA RIVER. OBVIOUSLY WE ARE WALKING A VERY
FINE LINE TODAY BETWEEN NOTHING HAPPENING ACROSS OUR NORTHERN TIER
AND A DECENT COVERAGE OF THUNDERSTORMS SO FELT USING PROBABILITY IN
THE TRUEST SENSE WAS THE MOST PRUDENT COURSE OF ACTION TODAY NOTING
THAT A 20 PERCENT CHANCE REALLY MEANS 80 PERCENT OF THE TIME IT WILL
NOT HAPPEN. DID FEEL REASONABLY CONFIDENT THAT TEMPERATURES NEED
TO GET CLOSE TO THEIR FORECASTED HIGHS TODAY TO TRIGGER CONVECTION
IN ANY FORM. THUS WOULD NOT EXPECT TO SEE MUCH RAIN FORMING UNTIL
AFTER 2 PM. ALSO WOULD NOT EXPECT IT TO LAST VERY LONG INTO THE
EVENING BUT DID NOT HAVE AS MUCH CONFIDENCE TO SHUT OFF THE THREAT
BY 8 PM SO LEFT IT IN PLACE FOR THE ENTIRE EVENING.
THE UPPER LOW WILL SLOWLY MOVE EAST OVERNIGHT WHILE AN UPPER RIDGE
BUILDS OFFSHORE. THIS WILL MAINTAIN A TYPICALLY DRIER NORTHWESTERLY
TO NORTHERLY FLOW AND BRING UNEVENTFUL WEATHER FOR THE REST OF THE
WEEKEND ASIDE FROM CLOUDS AT THE COAST AND PERHAPS SOME BRIEF
MORNING CLOUDS INLAND. TEMPERATURES NEAR OR SLIGHTLY ABOVE
NORMAL WILL GRADUALLY WARM FURTHER. /JBONK
.LONG TERM...SUNDAY THROUGH THURSDAY...NO CHANGES. PREVIOUS
DISCUSSION FOLLOWS. UPPER LEVEL RIDGING WILL MOVE ONSHORE ALLOWING
TEMPERATURES TO INCREASE SLIGHTLY ABOVE SEASONAL NORMS FOR THE
BEGINNING PART OF NEXT WEEK. AS THE RIDGE BEGINS TO BREAKDOWN
AND BECOME MORE ZONAL WE WILL SEE AN INCREASE IN LOW AND MID LEVEL
MOISTURE. THIS WILL PROVIDE FOR AN INCREASE IN CLOUD COVER FOR THE
LATTER PART OF NEXT WEEK. DO NOT EXPECT ANY PRECIPITATION IN THE
NEAR FUTURE. /64
&&
.AVIATION...A WEAKENING FRONT CONTINUES TO PUSH ONSHORE THIS
MORNING WITH PRIMARILY MVFR CIGS ALONG THE COASTAL AREAS ALONG
WITH SOME LIGHT DRIZZLE. SOME SCATTERED CLOUDS BELOW 1000 FT ALONG
THE CENTRAL OREGON COAST...SO CANNOT RULE OUT LOCAL IFR AT TIMES
THROUGH 18Z. THEREAFTER...EXPECT SCATTERED MID CLOUDS GRADUALLY
DIMINISHING FOR THE COAST WITH GUSTY WINDS POSSIBLE IN AFT 21Z S
OF KTMK. MEANWHILE...INCREASING MID CLOUDS ACROSS THE INTERIOR
THIS MORNING AS FRONT APPROACHES. EXPECT VARIABLE SCATTERED TO
BROKEN CLOUDS...TRENDING TOWARDS BROKEN 10Z-18Z BUT REMAINING VFR
WITH CLOUD DECK AT OR ABOVE 4500 FT. AFT 20Z...EXPECT CLEARING S
OF A KKLS-KPDX-KRDM LINE WITH SCT CLOUDS LINGERING N OF THIS LINE
BUT SCATTERING BY LATE AFTERNOON.
KPDX AND APPROACHES...VFR NEXT 24 HRS. INCREASING CLOUDS AT OR
ABOVE 4500 FT THROUGH 18Z AS WEAK FRONT APPROACHES...THEN
INCREASING CLEARING AT TERMINAL THEREAFTER. BKN-OVC DECK AROUND
4000 FT MAY PERSIST OVER EASTERN APPROACHES THROUGH 06Z SAT.
CULLEN
&&
.MARINE...A WEAK FRONT HAS PROGRESSED ACROSS THE WATERS EARLY THIS
MORNING AND WILL CONTINUE TO SLIDE ONSHORE THIS MORNING. HIGH
PRES THEN REBUILDS OVER THE COASTAL WATERS LATER TODAY AND WILL
PERSIST OVER THE NE PAC INTO NEXT WEEK. MEANWHILE...A THERMAL
TROUGH OVER NORTHERN CALIFORNIA WILL STRENGTHEN...WHICH WILL
INCREASE THE SURFACE PRES GRADIENT...PARTICULARLY OVER THE CENTRAL
OREGON WATERS. THEREFORE...N-NW WINDS WILL CONTINUE AND WILL BE
GUSTY AT TIMES...PARTICULARLY IN THE LATE AFTERNOON AND EVENING
HOURS. MAY SEE A FEW GUSTS TO 20 KT S OF CASCADE HEAD TODAY...BUT
GRADIENT SHOULD INCREASE SAT WITH WINDS POSSIBLY REACHING ADVISORY
CRITERIA.
SEAS WILL REMAIN 3 TO 5 FT TODAY...BUT REMAIN RELATIVELY STEEP
WITH A DOMINANT PERIOD AROUND 9 SECONDS. SEAS MAY INCREASE THIS
WEEKEND TO 5 TO 7 FT...ESPECIALLY IN AREAS WITH STRONGER WINDS
WITH A MIX OF WIND WAVE AND FRESH SWELL DOMINATING. STEEP
CONDITIONS LIKELY CONTINUE WITH MODELS SUGGESTING PERIODS
SHORTENING TO 7-8 SECONDS...SO WILL NEED TO MONITOR FOR POTENTIAL
ADVISORY FOR HAZARDOUS SEAS FROM SAT INTO EARLY NEXT WEEK. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
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
National Weather Service Spokane WA
232 AM PDT FRI AUG 22 2014
.SYNOPSIS...
Friday will bring another round of showers and thunderstorms to
the region with the potential for more flash flooding over the
Cascades burn scars. The threat of scattered showers and
thunderstorms will continue through the weekend. A drier and
warmer weather pattern is expected for the new work week.
&&
.DISCUSSION...
Friday: A deep upper-level low pressure system will pass through the
region today delivering widely scattered showers and thunderstorms.
Storms containing heavy rainfall and very little movement will be
the main concern as the risk for flash flooding and debris flows
remains elevated over the East Slopes and Okanogan Highlands.
Additional urban and rural areas could also experience localized
flooding impacts if a storm was to setup overhead. An isolated
stronger storm could also bring brief hail and gusty outflow
winds on the order of 40 mph.
2AM satellite reveals the center of the low crossing over the
Columbia Gorge near the Dalles. The low will shift east toward
the Tri Cities this morning...then continue toward the OR/WA/ID
border by midday before tracking into SE Idaho this evening. With
the low overhead, an unstable air mass will be in place with
500mb temperatures cooling near -17C. Meanwhile, a tongue of
richer moisture and instability...marked well by the 850-700mb
theta-e progs will wrap around the eastern and northern periphery
of the low...wrapping back south on its western edge. This richer
moisture in conjunction with little to no steering flow is a good
recipe for storms containing heavy rainfall. The good news is that
this lack of steering flow (storm movement) only resides through
late afternoon then as the system departs the east, increasing
northerly flow will give any lingering storms a push. Needless to
say, we saw what these storms are capable of Thursday afternoon
with numerous debris flows and mudslides within the Carlton
Complex burn scar.
As of 2AM...thunderstorms continue to go strong across the
northern mountains with additional development now over the lower
ID Panhandle. This activity is tied to the placement of the higher
theta-E axis and lift along the northeastern periphery of the
upper low dropping into the Pac NW. HRRR and local Hi-Res model
simulated radar suggest the larger area of showers/storms over
Ferry County will pivot to the west this morning, fall apart after
sunrise, allowing cells to redevelop after a few hours of
sunshine. Convective temperatures are only in the upper 60`s to
lower 70`s so it won`t take much. Whether the cloud cover from
this activity completely falls apart or just thins will be a major
challenge related to storm intensity this afternoon. For NE WA and
the ID panhandle, looks as if isolated storms will be possible
through morning then afternoon heating and a few vorticity
maximums will promote widely scattered storms again after the
12PM-3PM timeframe...continuing through the evening. Slightly
deeper wind shear over the lower ID Panhandle could support a few
organized cells capable of hail and wind gusts in excess of 40 mph
but overall, the threat for severe storms (hail and damaging
winds) remains low region-wide.
Saturday: The upper-low will continue its march east Friday night
and Saturday into Central Montana Saturday morning then North
Dakota by the evening. Look for drier north to northwest flow over
the Cascades and Western Basin Saturday morning to translate east
into the Idaho Panhandle by Saturday evening. The main
precipitation threat will concentrate over the ID Panhandle and
into Western Montana. Some models are more aggressive with the
drying so we may be on the high end for precipitation chances in
Idaho, especially west of a line from Mullan to the Blue Mtns.
Given the lingering cold pool aloft, a few convective showers will
be possible in the mountains all the way to the Cascade Crest but
these will be the weak and shallow variety producing little to no
rainfall.
We will also see breezy northerly winds as the low deepens today
then pulls out Saturday. Winds will be strongest through the
narrow Okanogan Valley and Purcell Trench. Winds sustained 10-20
mph with gusts to 35 mph are a strong possibility. Temperatures
will remain on the cool side of normal. /sb
Saturday night through Wednesday...General agreement exists
between the latest medium range models with the overall field of
motion. The general troffy and unsettled pattern will persist
through Sunday featuring a continued threat of showers and at
least isolated thunderstorms mainly during the afternoon and
evening hours and concentrated over the northern mountains...with
a few showers persisting well into the night over the Idaho
Panhandle. Temperatures in this polar influenced air mass will run
at or slightly below normal through Monday.
Monday appears to bring a transition from a general trough to a
new ridging cycle...with only a few lingering showers over the
northeast and panhandle while the remainder of the forecast area
dries out and stabilizes under the ridge driven warming aloft.
Tuesday through Wednesday bring high confidence of dry and
clear/partly cloudy conditions throughout the region as the polar
storm track retreats to the north with temperatures once again
cresting well above normal. /Fugazzi
Wednesday Evening through Thursday Night: Starting Wednesday
evening the strength of the ridge will be on the decline as the
next trough of low pressure approaches the region. Models are
still wavering a bit on the breakdown, but one thing in common for
now is Wednesday will be the warmest day of the forecast period.
Considering model differences for the breakdown, the GFS continues
to be much more aggressive bringing a deep trough swinging
through late Thursday. This solution would support another round
of widespread rain as the system would have both mid latitude
Pacific moisture as well as topical moisture from decaying
Tropical Storm Lowell to work with. The euro on the other hand
keeps the trough further north leading to a much drier zonal flow
pattern for the Pac NW. Either way, we are looking at breezy to
windy conditions for the later part of the week as cold air
advection coupled with a tightened pressure gradient increases the
winds. Both models have been fairly consistent in their respective
solutions, so the DGEX was used to help lean in one models favor.
It more closely followed the Euro leading to higher confidence in
it.
So leaning towards the euro, it delays the major threat of precip
beyond the reaches of this forecast so POPs were kept relatively low.
Temperatures were also raised a bit Thursday to show the
transition to a more zonal pattern rather than the cold incoming
trough from the GFS. One thing to keep in mind is that when models
try to ingest this tropical storm moisture, it often leads to some
inconsistent runs. Knowing this, the extended will need to be
tinkered with throughout the next couple of days as models align
better. /Fliehman
&&
.AVIATION...
06Z TAFS: A SOMEWHAT MOIST AND UNSTABLE AIR MASS ASSOCIATED WITH
AN AREA OF LOW PRESSURE WILL CONTINUE TO INFLUENCE THE AVIATION
AREA FOR THE NEXT 24 HOURS. DURING THE DAYTIME HOURS SURFACE BASED
CONVECTIVE SHOWERS AND THUNDERSTORMS WILL OCCUR, PRIMARILY OVER
AND NEAR MOUNTAIN LOCATIONS BUT MOST TAF LOCATIONS WILL BE UNDER
THREAT FOR A CLOSE MISS OR BRIEF THUNDERSTORM FRIDAY AFTERNOON AND
EVENING. /MJF
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 75 55 75 54 79 56 / 40 40 10 10 20 30
Coeur d`Alene 73 54 73 51 77 53 / 50 50 10 10 20 30
Pullman 75 51 74 49 79 51 / 40 50 20 20 20 20
Lewiston 80 60 79 56 85 59 / 60 50 30 20 10 20
Colville 72 51 78 49 81 52 / 60 50 10 10 20 30
Sandpoint 69 50 71 46 75 49 / 70 50 10 20 20 30
Kellogg 68 52 67 47 72 53 / 70 60 40 20 30 30
Moses Lake 81 58 83 56 86 58 / 30 50 10 0 10 10
Wenatchee 80 63 82 58 84 64 / 40 50 10 10 20 10
Omak 79 59 82 53 85 58 / 50 40 10 10 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch through this evening for East Slopes Northern
Cascades-Okanogan Valley-Wenatchee Area.
&&
$$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 215 PM CDT FRI AUG 22 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK
AREA OF LOW PRESSURE SPINNING OVER WESTERN WISCONSIN EARLY THIS
AFTERNOON. ALTHOUGH UPPER DIVERGENCE IN THE RIGHT REAR QUAD OF A
JET STREAK HAS SHIFTED OFF TO THE EAST...CONVERGENCE NORTH OF A
SURFACE WARM FRONT HAS GENERATED SCATTERED SHOWERS AND AN ISOLATED
THUNDERSTORM OVER NORTH-CENTRAL WISCONSIN. ALSO OBSERVING RATHER
BUBBLY LOOKING CU ALONG A COLD FRONTAL TYPE FEATURE MOVING INTO
CENTRAL WISCONSIN THOUGH CONVERGENCE LOOKS QUITE WEAK...AND THE
ONLY RETURNS ARE LOCATED OVER NORTHEAST IOWA. THE ATMOSPHERE IS
GROWING UNSTABLE AHEAD OF THIS TROUGH/COOL FRONT WITH ML CAPES
GROWING TO GREATER THAN 1000 J/KG...AND CIN FALLING RAPIDLY. THE
NAM CREATES CONVECTION OVER CENTRAL WISCONSIN LATER THIS
AFTERNOON...SO THIS IS SOMETHING TO KEEP AN EYE ON. INCLUDED A
ISOLATED THUNDERSTORM MENTION FOR THE REST OF THE AFTERNOON OVER
CENTRAL WISCONSIN. MEANWHILE...A LARGE UPPER TROUGH OVER THE PAC
NW WILL SHIFT EAST CAUSING A WARM FRONT TO RE-ORGANIZE OVER THE
PLAINS ON SATURDAY. PRECIP CHANCES AND FOG POTENTIAL REMAIN THE
MAIN FORECAST CONCERNS.
TONIGHT...MODELS ARE HAVING A TOUGH TIME LATCHING ON TO THAT LOW
LEVEL CIRCULATION OVER WESTERN WISCONSIN. THE NAM AND TO A LESSER
EXTEND THE GEM APPEAR TO HAVE A BETTER HANDLE ON THIS FEATURE THAN
OTHER GUIDANCE. BUT CONFIDENCE WILL REMAIN LOW IN ANY CASE. BOTH
THE NAM AND GEM SHOW THIS SURFACE LOW WEAKENING LATER THIS AFTERNOON
OR THIS EVENING AND MORPHING INTO A SURFACE TROUGH OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN. THIS WILL KEEP AN ISOLATED TO SCATTERED
THREAT OF SHOWERS AND STORMS INTO THE EVENING...AND POSSIBLY INTO
THE OVERNIGHT HOURS TOO. THIS TROUGH WILL ALSO PROMOTE FOG DEVELOPMENT
IN THESE AREAS TONIGHT AND THINK ANOTHER DENSE FOG ADVISORY WILL BE
POSSIBLE FOR THE EARLY MORNING COMMUTE TOMORROW. LIGHT EASTERLY
WINDS MAY ALSO ADVECT AREAS OF MARINE FOG INLAND INTO THE LAKESHORE
COUNTIES TONIGHT. WARM AND MUGGY WITH LOWS IN THE 60S.
SATURDAY...LOW PRESSURE WILL EMERGE INTO THE CENTRAL PLAINS AHEAD OF
A DEEP PAC NW TROUGH. THE LOW LEVEL FLOW WILL REORGANIZE AND A WARM
FRONT WILL LIFT INTO SOUTHWEST WISCONSIN IN THE AFTERNOON. THIS
LOOKS TO BE A LITTLE SLOWER THAN YESTERDAYS RUNS AND WILL BACK OFF
PRECIP CHANCES DURING THE MORNING. CHANCES IMPROVE DURING THE
AFTERNOON OVER CENTRAL AND NORTH-CENTRAL WISCONSIN BUT AM SKEPTICAL
SINCE THE FRONT WILL STILL BE WELL SOUTHWEST OF THE REGION AND
MID-LEVEL RIDGING SHARPENS ALOFT. SO WILL MATCH WITH OTHER OFFICES BUT
BRING UP CONCERN TO THE NEXT SHIFT. ONCE THE MORNING FOG AND LOW
CLOUDS BURN OFF...CONTINUED WARM AND HUMID WITH HIGHS IN THE UPPER
70S TO LOWER 80S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 215 PM CDT FRI AUG 22 2014
SATURDAY NIGHT INTO SUNDAY...THE UPPER RIDGE GETS NUDGED TO THE
EAST A TAD WHILE A BROAD UPPER TROUGH APPROACHES FROM THE
NORTHERN AND CENTRAL PLAINS. A DEEPENING LOW PRESSURE SYSTEM WILL
LIFT NORTHWARD OVER THE NORTHERN PLAINS...AND LIFT A WARM FRONT
NORTH OVER THE AREA. SOME PROGS GENERATE SOME CONVECTION WITH THIS
FRONT SAT NIGHT INTO SUNDAY MORNING. CONVECTION MAY STRUGGLE TO
DEVELOP DUE TO PROXIMITY TO THE UPPER RIDGE SO KEPT POPS ON THE LOW
SIDE AND DECREASED THE DURATION OF THE CONVECTION MENTION.
ISOLATED CONVECTION MAY LINGER SUNDAY MORNING ACROSS NORTHERN
WISCONSIN...BUT BY NOON THE H850 BOUNDARY IS PROGGED TO BE WELL
NORTH OF THE AREA. ANY PRECIPITATION CHANCES DURING THIS PERIOD
WILL TEND TO BE FOCUSED TOWARD NORTHWEST WISCONSIN TOWARD THE BEST
HEIGHT FALLS.
SUNDAY NIGHT INTO MONDAY...NEXT CHANCE OF CONVECTION ALONG A
TROUGH OR WEAKENING COLD FRONT. MOST MODEL RUNS DIMINISH THE PCPN
AS IT WORKS INTO EASTERN WISCONSIN CLOSER TO THE UPPER RIDGE WHICH
REMAINS OVER THE EASTERN GREAT LAKES AND MUCH OF THE EAST THIRD OF
THE COUNTRY. THE BRUNT OF THE CONVECTION WILL LIKELY TRACK OVER
NORTHWEST WISCONSIN AND ESPECIALLY OVER MINNESOTA NEAR THE
SURFACE AND 850 LOW LIFTING NORTHEAST.
MONDAY NIGHT...BROAD RRQ REGION OF THE UPPER JET FOCUSES THE
CONVECTION OVER THE CENTRAL PLAINS WHILE WHILE WEAK HIGH PRESSURE
BUILDS INTO THE REGION IN THE WAKE OF THE FROPA. THE GFS WAS THE
ODD MODEL OUT WITH STALLING THE FRONT OVER THE AREA AND
CONTINUING CONVECTION MONDAY NIGHT.
MOST OF THE MODELS FOR THE REST OF NEXT WEEK...THE UPPER PATTERN
SHIFTS FROM A SOUTHWEST FLOW ALOFT TO A NEARLY ZONAL FLOW LATE IN
THE WEEK...BUT SOME AGREEMENT WITH MOST MODELS WITH RESPECT TO A
MORE ROBUST SHORT WAVE WITH RRQ UPPER JET REGION PASSING THROUGH
TOWARD MID WEEK. COULD SEE ANOTHER ROUND OF A SOAKING RAIN WITH
THE SURFACE FRONT AND H850 FRONT INTERACTING WITH THE UPPER JET.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH TUESDAY...AND WELL ABOVE
NORMAL IN A STICKY AIR MASS SUNDAY ESPECIALLY IF THE CLOUDS CLEAR
OUT. TEMPERATURES COOLING BACK TO NEAR NORMAL LATER NEXT WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1206 PM CDT FRI AUG 22 2014
A WARM AND VERY MOIST LATE SUMMER AIRMASS WILL REMAIN IN PLACE
THROUGH THE TAF PERIOD. WEAK LOW LEVEL CONVERGENCE WILL PROMOTE
ISOLATED TO SCATTERED SHOWER DEVELOPMENT THIS AFTERNOON OVER
NORTH-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THE ISOLATED
SHOWERS COULD LINGER INTO THE EVENING OVER FAR N-C WISCONSIN.
OTHERWISE...EXPECT CIGS AND VSBYS TO LOWER QUICKLY BY MID TO LATE
EVENING ACROSS THE REGION...WITH AREAS OF DENSE FOG DEVELOPING AGAIN
LATE TONIGHT. CIGS AND VSBYS TO IMPROVE VERY SLOWLY TOMORROW
MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT THU AUG 21 2014
.UPDATE...
ISSUED AT 908 PM CDT THU AUG 21 2014
THE MAIN FOCUS FOR THE OVERNIGHT HOURS IS WITH CONVECTIVE TRENDS
AND THE POTENTIAL FOR WIDESPREAD FOG.
SO FAR THIS EVENING...THE MAIN CONVECTION HAS BEEN TIED TO A
NARROW CORRIDOR ALONG AND AHEAD OF A SURFACE COLD FRONT/LOW THAT
RUNS FROM NORTHWEST WISCONSIN THROUGH SOUTH CENTRAL MINNESOTA.
22.01Z RAP ANALYSIS SHOWS THAT SBCAPE IS ON THE WANE WITH THE TWO
MAIN AREAS OF CONVECTION ALONG THE NORTHERN GRADIENT IN
INSTABILITY...NW WI...AND THE OTHER MAIN CELLS ALONG THE HIGHEST
INSTABILITY AXIS POKING INTO NW IOWA. THE MAIN CONVERGENCE WILL
REMAIN WITH THIS SLOW MOVING FRONT THROUGH THE NIGHT THOUGH
SURFACE/LOW LEVEL WINDS WILL BE DECREASING THROUGH THE NIGHT THUS
WEAKENING THIS CONVERGENCE. WHILE SFC/ML INSTABILITY WILL BE
DECREASING THROUGH THE NIGHT...0-3KM MUCAPE ACTUALLY GETS A BUMP
UP PER THE 22.01Z RAP AS THE FRONT APPROACHES LATE. THERMAL
PROFILES ARE FAIRLY WARM...SO IT WILL TAKE QUITE THE UPDRAFT TO
GET ANY OF THE CONVECTION TO GO SEVERE WHICH DOES NOT LOOK LIKE IT
WILL HAPPEN BASED ON THE WEAKENING CONVERGENCE. STILL MAY MANAGE
TO SEE A FEW SHOWERS...JUST NOT EXPECTING ANYTHING THAT WOULD GET
OUT OF HAND.
WITH A HUMID AIR MASS IN PLACE WITH SURFACE DEW POINTS IN THE LOW
70S...FOG STILL LOOKS LIKE A POSSIBILITY OVERNIGHT. THE 21.21Z
SREF IS LOCKING ONTO NORTHERN WISCONSIN WHERE IT APPEARS THAT A
WEAK WARM FRONT IS LOCATED AND SOME LOCATIONS HAVE ALREADY STARTED
TO DROP BELOW 1SM. WITH WINDS LIGHTENING UP AS THE LOW/FRONT
APPROACHES...SOME MORE SITES COULD DEVELOP FOG OVERNIGHT IF THE
SKIES CAN CLEAR OUT. HIGH LEVEL CLOUD COVER IS BLOWING OFF OF THE
CONVECTION IN SOUTHWEST MINNESOTA AND COULD INITIALLY SLOW THINGS
DOWN...BUT EXPECT THAT SKIES WILL CONTINUE TO CLEAR AND LEAD TO
THIS FOG DEVELOPMENT. CONFIDENCE IS NOT HIGH ENOUGH IN THE
WHEN/WHERE TO ISSUE A DENSE FOG ADVISORY...BUT SOME PORTION OF THE
AREA MAY NEED ONE LATER.
&&
.SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 340 PM CDT THU AUG 21 2014
WATER VAPOR IMAGERY SHOWING THE STRONG MID-LEVEL WAVE THAT GAVE THE
AREA MAINLY MORNING SHOWERS AND THUNDERSTORMS NOW OVER EASTERN WI.
SUBSIDENCE IN THE WAKE OF THIS WAVE PROVIDED SOME PARTIAL SUNSHINE
TO THE ARX FORECAST AREA WITH TEMPERATURES THIS AFTERNOON IN THE MID
70S TO THE LOWER 80S. ALSO...DEW POINTS WERE CREEPING UPWARD INTO
THE MIDDLE 60S TO THE LOWER 70S FOR A BIT MORE MUGGY FEEL TO THE
ATMOSPHERE.
MODEL CONSENSUS SHOWS WARM FRONTAL BOUNDARY REMAINING JUST TO OUR
SOUTH OVERNIGHT WITH MODELS INDICATING SOME 850MB MOISTURE TRANSPORT
INTO/OVER IT. THIS IS IN ADVANCE OF A WEAKER MID-LEVEL WA
DETERMINISTIC MODELS LOOK BIT OVERDONE WITH QPF BASED ON THIS WEAKER
SIGNAL...SO WENT WITH SMALLER-END SHOWER/THUNDER CHANCES. WITH
RECENT RAINFALL AND RELATIVELY WEAK WINDS OVERNIGHT...ANY BREAKS IN
THE CLOUD COULD ALSO LEAD TO SOME FOG DEVELOPMENT.
FRIDAY IS LOOKING MAINLY DRY ACROSS THE AREA WITH MID-LEVEL RIDGE
AMPLIFYING OVERHEAD. HOWEVER...THE BOUNDARY WILL REMAIN JUST TO OUR
SOUTH BUILDING INSTABILITY THROUGH THE AFTERNOON. NO REAL TRIGGER
MECHANISM TO FOCUS CONVECTION OTHER THAN WEAK CONVERGENCE ALONG THE
BOUNDARY. AS SUCH...WILL GO WITH A 20-30 PERCENT CHANCE OF
SHOWERS/THUNDERSTORMS ACROSS PORTIONS OF NORTHEAST IA/SOUTHWEST WI.
OTHERWISE...PLAN ON HIGHS IN THE 80S WITH HEAT INDICES CREEPING INTO
THE 95-100 DEGREE RANGE ACROSS FAR NORTHEAST IA/FAR SOUTHWEST WI.
FOR FRIDAY NIGHT...LOOKING FOR THAT BOUNDARY TO OUR SOUTH LIFT NORTH
AS A WARM FRONT. THIS IS IN RESPONSE TO SURFACE CYCLOGENESIS OVER
THE CENTRAL PLAINS. MODELS IN GOOD AGREEMENT IN KEEPING BEST 850MB
MOISTURE TRANSPORT FOCUSED MORE ACROSS WESTERN IA/MN. AS SUCH...KEPT
HIGHER POPS FOCUSED MORE ACROSS NORTHEAST IA/SOUTHEAST MN...TAPERING
EASTWARD OF THE MISSISSIPPI. PRECIPITABLE WATER VALUES WILL BE QUITE
HIGH IN THE 1.5-2 INCH RANGE...SO ANY STORMS WILL BE CAPABLE OF SOME
HEAVIER RAINFALL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 PM CDT THU AUG 21 2014
LOOK FOR THE WARM FRONT TO CONTINUE TO PUSH NORTHWARD ACROSS THE
AREA SATURDAY THROUGH SATURDAY NIGHT FOR ADDITIONAL SHOWER AND
THUNDERSTORM CHANCES. WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR
POCKETS OF HEAVIER RAINFALL GIVEN HIGHER-END PRECIPITABLE WATER
VALUES. SATURDAY AFTERNOON INTO SATURDAY EVENING MAY ALSO HAVE TO BE
WATCHED FOR SEVERE THUNDERSTORM POTENTIAL AS NAM INDICATING 0-3KM
MUCAPE IN THE 2000-4500J/KG RANGE WITH BULK SHEAR IN THE 20-25KT
RANGE. LOOKS LIKE THE HIGHEST THREAT AREA WOULD BE ALONG AND WEST OF
THE MISSISSIPPI RIVER.
SUNDAY LOOKING HOT/MUGGY/CAPPED AS THE AREA BECOMES ENTRENCHED IN
THE WARM SECTOR OF SURFACE LOW LIFTING NORTH ACROSS THE DAKOTAS INTO
CANADA. NAM DRAWING IN 27-31C 925MB AIR INTO AREAS ALONG/WEST OF THE
MISSISSIPPI RIVER IN THIS WARM SECTOR WHICH WOULD DICTATE
TEMPERATURES NEARING 100. TOOK A MODEL CONSENSUS FOR NOW...YIELDING
HIGHS IN THE 90S. WITH DEWPOINTS IN THE 70S...RESULTING HEAT INDICES
WILL BE IN THE 100-105 DEGREE RANGE FOR AREAS ALONG AND SOUTH OF I-
90. WILL KEEP AN EYE ON THIS OVER THE NEXT DAY OR TWO FOR A POSSIBLE
HEAT HEADLINE.
SHOWER/THUNDERSTORM CHANCES RETURN SUNDAY NIGHT INTO MONDAY AS A
COLD FRONT PUSHES INTO THE AREA. THIS FRONTAL BOUNDARY LOOKS LIKE IT
WILL LINGER ACROSS AREA THROUGH AT LEAST WEDNESDAY FOR A CONTINUED
CHANCE OF SHOWERS AND THUNDERSTORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1149 PM CDT THU AUG 21 2014
THE MAIN FOCUS IS ON THE FOG OVERNIGHT AS MUCH OF THE CONVECTION
IS STAYING WELL OFF TO THE NORTHEAST OF THE TAF SITES. WITH A
HUMID AIR MASS IN PLACE AND WINDS LIGHTENING UP...SOME WIDESPREAD
FOG IS EXPECTED OVERNIGHT...POSSIBLY DENSE. CONDITIONS SHOULD
IMPROVE BY LATE MORNING AS TEMPERATURES JUMP UP AND CAUSE THE FOG
TO MIX OUT. THE MAIN NEGATIVE FOR THE FOG IS WITH SOME MID LEVEL
CLOUDS THAT ARE COMING ACROSS THE REGION FROM EARLIER CONVECTION
THAT OCCURRED ALONG THE MINNESOTA/IOWA BORDER. ONCE THAT CLEARS
OUT...THE FOG SHOULD DEVELOP.
&&
.HYDROLOGY...TODAY INTO TONIGHT
ISSUED AT 340 PM CDT THU AUG 21 2014
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA FRIDAY NIGHT
THROUGH SATURDAY NIGHT AND SERVE AS A TRIGGER FOR
SHOWER/THUNDERSTORM DEVELOPMENT. PRECIPITABLE WATER VALUES WILL BE
IN THE 1.5 TO 2 INCH RANGE. AS SUCH...ANY STORM WILL BE CAPABLE OF
HEAVY RAINFALL. NOT THINKING ANY FLOOD HEADLINES WILL BE NEEDED AT
THIS TIME BUT CERTAINLY WARRANTS A WATCHFUL EYE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
329 PM MDT FRI AUG 22 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM MDT FRI AUG 22 2014
PRETTY ACTIVE THE NEXT 24 TO 48 HOURS. TEMPERATURES AND POPS ARE
THE FORECAST CHALLENGES FOR THE SHORT TERM.
CURRENTLY...WATER VAPOR IMAGERY SHOWING A PRETTY PRONOUNCED WAVE
IN THE MONSOONAL FLOW MOVING NORTH THIS AFTERNOON OUT OF NEW
MEXICO INTO WEST CENTRAL COLORADO. MOSAIC RADAR SHOWING WIDESPREAD
SHOWERS OVER CENTRAL COLORADO EARLY THIS AFTERNOON WITH A GENERAL
NORTH NORTHEAST MOVEMENT ON THE CELLS. INFRARED RADAR SHOWING
COOLING CLOUD TOPS WITH THIS WAVE AND WE ARE SEEING AN UPTICK IN
LIGHTNING STRIKES ACROSS WESTERN COLORADO. UPPER LOW OVER IDAHO
FAIRLY DYNAMIC AS WELL WITH NUMEROUS LIGHTNING STRIKES DEVELOPING.
LATEST SPC MESOANALYSIS SHOWING A SLOW EROSION OF CIN OVER EXTREME
SOUTHEAST WYOMING INTO THE KIMBALL AREA...WITH CAPE VALUES
AROUND 1000 J/KG ABOVE. LOOKING AT CLOUD COVER OVERHEAD...IT IS
PRETTY DENSE AND WE HAVE BEEN HARD PRESSED TO GET MUCH WARMING SO
FAR TODAY. 1 PM TEMPERATURES HERE AT THE OFFICE AT 69 DEGREES WITH
LOW TO MID 70S OUT IN THE PANHANDLE.
FOR THIS EVENING...SHORTWAVE BEGINS TO MOVE INTO SOUTHEAST WYOMING
SHORTLY AFTER 00Z WITH GUIDANCE INDICATING FAIRLY WIDESPREAD
CONVECTION DEVELOPING AS THIS HAPPENS. THE 16Z HRRR FORECAST HAS
CONVECTION DEVELOPING HERE AT CHEYENNE AROUND THE 22Z
TIME FRAME...THEN EXPANDING ACROSS SOUTHERN WYOMING INTO THE
PANHANDLE AFTER WARDS. BY 01Z...MOST LOCATIONS EAST OF THE LARAMIE
RANGE SHOULD BE SEEING MEASURABLE RAINFALL WITH SCATTERED SHOWERS
OUT WEST. NAM SOUNDINGS FOR THE PANHANDLE SHOWING PRETTY STRONG
SHEAR OUT IN THE PANHANDLE THIS EVENING. LOOKING AT EASTERLY WINDS
NEAR THE SURFACE OF 15 TO 20KTS WITH SOUTHWEST 40-45KTS AT 6KM.
EVENING SHIFT WILL DEFINITELY NEED TO BE WATCHING FOR SEVERE
THUNDERSTORMS. 0-3KM HELICITY FOR SIDNEY AT 386M2/S2 AT 00Z. GIVEN
THE THICK CLOUD COVER THOUGH...CHANCES ARE DIMMING THAT WE WILL
SEE SEVERE THUNDERSTORMS.
SOMETHING ELSE FOR THIS AFTN/EVE...PRECIPITABLE WATER VALUES
REALLY HIGH FOR THE PANHANDLE. SIDNEY SOUNDING SHOWING 1.42
INCHES...EXTENDING UP TO CHADRON AT 1.40 INCHES. FORECAST QPF
REALLY HIGH FOR THE PANHANDLE AND EXTREME EASTERN WYOMING TONIGHT.
GOOD NEWS IS FORECAST STORM MOTIONS ARE FROM THE SOUTHWEST AT
14-16KTS...SO THESE STORMS SHOULD BE MOVING FAIRLY FAST. WILL NEED
TO WATCH THOUGH FOR TRAINING THUNDERSTORMS AND THERE COULD BE SOME
FLASH FLOODING FOR SOME AREAS THIS EVENING.
GFS AND ECMWF HAVE COME INTO DECENT AGREEMENT WITH THE UPSTREAM
LOW ON THIS 12Z RUN. BOTH SHOWING THE CLOSED LOW MOVING PRETTY
SLOW THROUGH NORTHERN WYOMING THROUGH THE DAY SATURDAY. MOST OF
SATURDAY WILL SEE SHOWERS LASTING MOST OF THE DAY. WENT
SIGNIFICANTLY HIGHER ON POPS OVER GUIDANCE. DO BELIEVE THE MID
SHIFT WILL PROBABLY WANT TO GO HIGHER.
FINALLY SATURDAY EVENING...THE UPPER LOW MOVES OFF INTO SOUTH
DAKOTA WITH RAIN ENDING FROM WEST TO EAST. GOING TO BE PRETTY COOL
WITH 700MB TEMPERATURES DOWN TO +6C SATURDAY NIGHT. SHOULD SEE
WIDESPREAD 40S OUT WEST FOR LOWS...WITH LOW 50S EAST. CLOUD COVER
COULD PROVIDE SLIGHTLY WARMER TEMPERATURES...WE WILL HAVE TO SEE
AS THE EVENT GETS CLOSER. DID GO UNDER GUIDANCE FOR SUNDAY
LOWS...ESPECIALLY OUT WEST WHERE CLOUD COVER WOULD BE LESS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 335 PM MDT FRI AUG 22 2014
MEDIUM RANGE MODELS IN GOOD AGREEMENT THROUGH EARLY TUESDAY...BUT
THEN SOLUTIONS BEGIN TO DIVERGE THROUGH WEDNESDAY...WITH POOR
CONSISTENCY BETWEEN THE 12Z AND 00Z MODEL RUNS APPARENT INTO LATE
NEXT WEEK. EARLY IN THE WEEK...MOIST SOUTHWEST FLOW AHEAD OF A
POSITIVELY TILTED UPPER LEVEL TROUGH WILL MOVE ACROSS ACROSS THE
IDAHO AND INTO WESTERN WYOMING. A WEAK BOUNDARY WILL DEVELOP AND
DRIFT WESTWARD ALONG THE LARAMIE RANGE...WHICH WILL RESULT IN
UPSLOPE FLOW AND ENHANCE LIFT ACROSS THE HIGH PLAINS. KEPT POP
BETWEEN 35 TO 60 PERCENT ACROSS THE AREA WITH A GOOD CHANCE OF AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS. ALL MODELS SHOW THIS
ACTIVITY LINGERING THROUGH MONDAY NIGHT AS WELL AS A WAVE OF LOW
PRESSURE DEVELOPS ALONG THE BOUNDARY...WHICH WILL EVENTUALLY
TRANSITION INTO A COLD FRONT. KEPT POP AROUND 50 PERCENT MONDAY
NIGHT. WILL HAVE TO WATCH FOR STRONG TO SEVERE THUNDERSTORMS
MONDAY EVENING WITH CAPE VALUES AROUND 1500 TO 2000 J/KG...HIGH
PW/S...AND INSTABILITY.
ECMWF STILL TRENDING SLOWER WITH THE UPPER LEVEL TROUGH COMPARED
TO THE GFS. THE GEM HAS TRENDED TOWARDS THE ECMWF WHILE THE GFS
PUSHES THE TROUGH THROUGH THE FORECAST AREA AS EARLY AS TUESDAY
AFTERNOON. THE ECMWF AND GEM SHOW THE TROUGH AXIS MOVING ACROSS
THE AREA LATE TUESDAY NIGHT AND EARLY WEDNESDAY. THE GEM AND ECMWF
SOLUTIONS THEN DIVERGE WITH THE ECMWF SHOWING THE SYSTEM
ATTEMPTING TO CLOSE OFF ON WEDNESDAY. EITHER WAY...EXPECT TUESDAY
AND TUESDAY EVENING TO REMAIN UNSETTLED WITH COOLER THAN NORMAL
TEMPERATURES AND A GOOD CHANCE OF WIDESPREAD RAINFALL. HIGHS MAY
STRUGGLE TO REACH THE MID TO UPPER 60S ON TUESDAY AS 700MB
TEMPERATURES LOWER BELOW 5C AFTER THE FRONT MOVES THROUGH THE
AREA. LOW CONFIDENCE ON THE WEDNESDAY FORECAST DUE TO SIGNIFICANT
MODEL DIFFERENCES. KEPT A SLIGHT CHANCE OF SHOWERS AND TSTORMS FOR
NOW DUE TO TIMING DIFFERENCES...EVEN THOUGH THE ECMWF SOLUTION IS
UNLIKELY TO OCCUR.
MUCH DRIER AIR MOVES INTO THE REGION THURSDAY AND FRIDAY BASED ON
CURRENT MODEL RUNS AS THE RIDGE AXIS REDEVELOPS WEST OF THE ROCKY
MOUNTAINS AND DRIFTS EASTWARD. BASED ON 12Z MODELS...WARMER
TEMPERATURES AND DRY CONDITIONS ARE EXPECTED NEXT WEEK.
HOWEVER...THERE IS A LARGE CONTRAST BETWEEN THESE SOLUTIONS AND
THE PREVIOUS 00Z SOLUTIONS FROM LAST NIGHT WHICH SHOW A PACIFIC
SYSTEM MOVES INTO THE REGION WITH ANOTHER STRONG COLD FRONT
ENTERING WYOMING BY LATE FRIDAY. KEPT TEMPERATURES NEAR NORMAL FOR
NOW WITH POP BELOW 10 PERCENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 1145 AM MDT FRI AUG 22 2014
A BAND OF RAIN SHOWERS AND ISOLATED THUNDER WILL CONTINUE OVER THE
SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT HOUR OR TWO BEFORE
DISSIPATING BY EARLY THIS AFTERNOON. EXPECT A BRIEF BREAK...WITH
MAINLY VFR CONDITIONS THIS AFTERNOON. THE ONLY EXCEPTION WILL BE
KCDR WHICH WILL MAINTAIN A LOW STRATUS DECK. ALL MODELS INDICATE AN
AREA OF HEAVY SHOWERS AND STRONG THUNDERSTORMS DEVELOPING OVER THE
HIGH PLAINS SOMETIME LATE THIS AFTERNOON AS A STRONG UPPER LEVEL
DISTURBANCE LIFT NORTHWARD OUT OF NEW MEXICO...AND WILL CONTINUE TO
MOVE NORTHWARD ACROSS THE AREA TONIGHT. FAIRLY CONFIDENT OF MVFR OR
IFR CONDITIONS IN THESE HEAVY SHOWERS WITH THE POTENTIAL FOR FOG AND
LOW STRATUS RESULTING IN AN EXTENDED PERIOD OF BORDER-LINE IFR
CONDITIONS INTO SATURDAY MORNING ACROSS THE HIGH PLAINS. KRWL AND
KLAR SHOULD REMAIN VFR TONIGHT WITH MOST OF THE ACTIVITY FURTHER TO
THE EAST...BUT CAN NOT RULE OUT SOME SHOWERS AND TSTORMS OVER THOSE
AREAS AS WELL.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT FRI AUG 22 2014
MINIMAL FIRE WEATHER CONCERNS ACROSS THE AREA THROUGH THE NEXT FEW
DAYS. UPPER LOW PRESSURE OVER IDAHO THIS AFTERNOON WILL BRING
INCREASING MONSOONAL MOISTURE AND FAIRLY WIDESPREAD RAINFALL TO
MUCH OF THE AREA TONIGHT INTO SATURDAY. BEST CHANCES FOR WETTING
RAINS WILL BE ALONG AND EAST OF THE LARAMIE RANGE AS WELL AS THE
SNOWY AND SIERRA MADRE RANGES. THE UPPER LOW WILL GRADUALLY MOVE
INTO WESTERN SOUTH DAKOTA EARLY SUNDAY MORNING WITH RAINS ENDING
FROM WEST TO EAST. COOLER TEMPERATURES BEHIND THE LOW WILL KEEP
AFTERNOON HUMIDITIES FAIRLY HIGH WITH EXCELLENT OVERNIGHT
RECOVERIES THROUGH THE MIDDLE OF NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
302 AM EDT SUN AUG 24 2014
.SYNOPSIS...
A WEAK BACK DOOR COLD FRONT ACROSS THE AREA THIS MORNING WILL PUSH
SOUTH OF THE REGION BY THIS AFTERNOON. A FEW SHOWERS ARE POSSIBLE
ALONG AND AHEAD OF THE FRONT. HIGH PRESSURE CENTERED OVER THE
NORTHEASTERN STATES WILL EXTEND INTO THE CAROLINA THROUGH MID WEEK
RESULTING IN FAIR WEATHER WITH NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER LEVEL RIDGE CONTINUES CENTERED OVER THE MISSISSIPPI VALLEY.
UPPER TROUGH OFF THE NEW ENGLAND AND MID ATLANTIC COAST. WEAK
SURFACE COLD FRONT NEAR CAE AT 07Z WILL SLOWLY PUSH SOUTH OF THE
AREA BY THIS AFTERNOON. A FEW SHOWERS CAN BE EXPECTED ALONG AND
AHEAD OF THE FRONT MAINLY THIS MORNING...BUT LACK OF LOW LEVEL
CONVERGENCE...UPPER SUPPORT AND WEAK INSTABILITY WILL LIMIT
COVERAGE. RADAR AT 07Z SHOWING SOME CONVECTION IN THE
PIEDMONT. RAP AND HRRR SUGGEST LOW POPS IN MIDLANDS. STRONGER
CONVERGENCE WILL SHIFT INTO GEORGIA BY THIS AFTERNOON AND EXPECT
DECREASING THREAT OF RAIN BY 18Z. WEAK INSTABILITY SO THUNDER
THREAT LOW. CONSIDERABLE LOW CLOUDS EARLY THIS MORNING WITH BREAKS
DEVELOPING BY MIDDAY THEN DECREASING CLOUDINESS IN THE AFTERNOON
AS DRIER AIR FROM NORTH CAROLINA ADVECTS SOUTH INTO THE REGION.
SHOULD BE COOLER BEHIND FRONT THIS AFTERNOON WITH NORTHEAST
FLOW/WEAK COLD ADVECTION. MOS TEMPERATURES CLOSE AND
ACCEPTED...UPPER 80S AROUND 90.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
HIGH PRESSURE OVER THE NORTHEASTERN STATES WILL BE BUILDING
SOUTHWEST INTO THE CAROLINAS THROUGH THE PERIOD. DRIER AIR ADVECTING
INTO THE REGION THIS EVENING WITH PRECIPITABLE WATER DECREASING TO
LESS THAN 1 INCH BY MONDAY AFTERNOON. DRY CONDITIONS WITH
SEASONABLE TEMPERATURES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA FOR MUCH OF THE WEEK. ANOTHER
COLD FRONT WILL APPROACH THE AREA BY SATURDAY...WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY. COOLER DRY AIR
SETTLING IN WILL BRING NEAR NORMAL TEMPS...WITH MAX TEMPS MAINLY IN
THE UPPER 80S TO THE LOWER 90S. OVERNIGHT MINS WILL BE 65 TO 70
RISING INTO THE LOWER 70S LATER IN THE WEEK.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD...WITH EARLY MORNING
MVFR CIGS.
WEAK FRONTAL BOUNDARY CONTINUES TO SLOWLY CROSS THE REGION WITH A
FEW SHOWERS AROUND CLT AND SOUTH OF AGS/DNL. EXPECT SHOWERS TO
CONTINUE CROSSING THE AREA OVERNIGHT...HOWEVER WITH LIMITED
COVERAGE HAVE NOT INCLUDED IN TAFS ATTM. WITH THE BOUNDARY AND
MOISTURE OVER THE REGION CIGS WILL LOWER TO MVFR BETWEEN 10 AND
15Z WITH CIGS SLOWLY IMPROVING THROUGH THE AFTERNOON AS THE
BOUNDARY SLIDES SOUTH OF THE TAF SITES. WINDS WILL BE
NORTHEASTERLY AROUND 5 KNOTS THROUGH 15Z...INCREASE TO 11 KNOTS
WITH GUSTS TO 17 KNOTS BETWEEN 15 AND 23Z...FINALLY SUBSIDING TO 8
KNOTS FOR THE REMAINDER OF THE PERIOD.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
140 AM EDT SUN AUG 24 2014
.UPDATE...
/ISSUED AT 1042 PM EDT SAT AUG 23 2014/
COMPLEX OF SHOWERS/TSTORMS OVER SRN KY/NRN TN WAS PROGRESSING SOUTH.
THIS AREA IS DIMINISHING IN SIZE AND COVERAGE...HOWEVER EACH RUN OF
THE HRRR BRINGS IT CLOSER TO THE GA BORDER AFTER MIDNIGHT. WILL
THEREFORE INCREASE POPS TO CHANCE POPS ACROSS EXTREME NORTH GA AFTER
MIDNIGHT. NO OTHER CHANGES PLANNED.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
/ISSUED AT 346 PM EDT SAT AUG 23 2014/
NO CHANGES PLANNED TO THE CURRENT HEAT ADVISORY HEADLINE THIS
AFTERNOON. TEMPERATURES ARE EXPECTED TO BE COOLER TOMORROW...SO NO
EXTENSION INTO SUNDAY IS PLANNED AT THIS TIME.
19Z SURFACE ANALYSIS SHOWS A WEAK TROUGH ACROSS NE GA...WHILE HIGH
PRESSURE IS CENTERED ACROSS THE GULF STATES. 500MB ANALYSIS SHOWS A
WEAK SHORTWAVE DIVING SOUTH ACROSS WESTERN GA THIS AFTERNOON. THIS
SHORTWAVE HAS HELPED INITIATE AND SUSTAIN SOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS NORTHERN GA THIS AFTERNOON. LATEST RUNS OF THE
HRRR KEEP CONVECTION GOING...ESPECIALLY ACROSS NW GA...INTO THE
EVENING HOURS AS THE SHORTWAVE CONTINUES TO IMPACT THE CWFA. DO
EXPECT CONVECTION TO BEGIN DIMINISHING BY THE LATE EVENING.
MODELS HAVE BEEN PERSISTENT IN BRINGING A BACKDOOR FRONTAL BOUNDARY
INTO NE GA TOMORROW. THE SURFACE FLOW WILL SWITCH AROUND TO THE EAST
OVERNIGHT...AND LOW LEVEL MOISTURE WILL BEGIN TO INCREASE ALONG AND
JUST AHEAD OF THE APPROACHING BOUNDARY. MODELS HAVE ALSO BEEN VERY
CONSISTENT IN PRODUCING HIGH POPS FOR THIS PERIOD. WITH THE
INCREASED CLOUD COVER AND PRECIPITATION...TEMPERATURES ACROSS THE
NORTHERN CWFA WILL BE SEVERAL DEGREES COOLER THAN TODAYS READINGS.
TEMPERATURES ACROSS THE SOUTHERN CWFA WILL HEAVILY DEPEND UPON HOW
FAR SOUTH THE BOUNDARY MAKES IT. MADE SOME MINOR TWEAKS TO THE
PRECIP TIMING...BUT OVERALL...NO MAJOR CHANGES TO THE POPS.
MODELS ARE DIMINISHING PRECIP CHANGES DURING THE EVENING HOURS.
HAVE NOT MADE MANY CHANGES TO THE SUNDAY NIGHT PERIOD.
NLISTEMAA
.LONG TERM /MONDAY THROUGH SATURDAY/...
/ISSUED AT 346 PM EDT SAT AUG 23 2014/
PATTERN IN BEGINNING OF LONG TERM PERIOD DOMINATED BY LARGE
POSITIVELY TILTED UPPER RIDGE OVER ALL SOUTHERN AND EASTERN STATES
WITH TROUGH ON EITHER SIDE...ONE OVER WESTERN CONUS AND ANOTHER
HIGHLY POSITIVELY TILTED TROUGH IN THE WESTERN ATLANTIC
PARALLELING THE EAST COAST. 12Z MED RANGE MODELS EXPANDS SOUTH AND
EAST CONUS RIDGE THRU EARLY WED WHILE PIECE OF WESTERN ATLANTIC
TROUGH DIPS SOUTH TOWARDS DEVELOPING TROPICAL SYSTEM. QUITE A
COMPLICATED PATTERN AND MAKES FORECASTING TRACK OF INVEST 96L
PROBLEMATIC. BY THURS...PATTERN BECOMES MORE ZONAL WITH BROAD
TROUGH OVER THE CENTRAL US AND BROAD RIDGES OVER THE WEST AND
EAST. 12Z GFS IS SLOWER WITH THE CENTRAL US TROUGH WHICH GIVES
A MORE WESTERN TRACK TO 96L...WHICH BASED ON RECENT MODEL RUNS AND
CONTINUED HIGH PROBABILITIES FROM NHC OUTLOOKS WILL LIKELY BECOME
TS CRISTOBAL. 12Z ECMWF SLIGHTLY MORE NORTHERN TRACK BUT BOTH
MODELS COMING INTO SIGNIFICANTLY BETTER AGREEMENT.
AS LONG AS TRACK DOES NOT SHIFT DRAMATICALLY WEST AND SOUTH FROM
CURRENT TRACK...IMPACT TO THE AREA WILL BE MINIMAL WITH DEEP DRY
AIRMASS AND SLIGHTLY STRONGER SFC WINDS.
COULD SEE ISOLD SHRA/TSRA BY THURS-FRI AS SLOW-MOVING CENTRAL US
TROUGH APPROACHES REGION FROM THE WEST.
SNELSON
PREV LONG TERM DISCUSSION /SUNDAY NIGHT THROUGH FRIDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
UPPER RIDGE CONTINUES TO DOMINATE AT THE BEGINNING OF THE
EXTENDED...WHILE SFC RIDGE BUILDS ACROSS THE MID ATLANTIC AND
DOWN THE APPALACHIANS. WITH THE PSEUDO WEDGE BUILDING IN...WINDS
BECOME EASTERLY AND CLOUD COVERAGE REMAINS BKN AT LEAST INITIALLY.
CLOUD COVERAGE DOES HELP TO KEEP TEMPS ON THE COOLER SIDE ON
MONDAY. DRIER AIR MOVES IN FOR THE FIRST HALF OF THE WEEK /BEHIND
THE BACKDOOR FRONT/. WITH THIS...DO NOT HAVE MOISTURE AROUND FOR
MUCH IN TERMS OF PRECIP AND THUS HAVE LIMITED POPS TO NO MENTION
OR SLIGHT CHANCE. DIFFERENCES EXIST BETWEEN THE GFS AND ECMWF IN
THE SECOND HALF THE OF THE EXTENDED. GFS BRINGS A COLD FRONT INTO
THE AREA ON FRIDAY...WHILE THE ECMWF KEEPS AN UPPER RIDGE ACROSS
THE SOUTHEAST. HAVE TENDED MORE TOWARDS THE GFS AND SHOWN AN
INCREASE IN CLOUDS/PRECIP FOR FRIDAY ASSOCIATED WITH THE FRONT.
DIFFERENCES ALSO EXIST STILL WITH HOW THE MODELS ARE HANDLING THE
POTENTIAL TROPICAL SYSTEM NEXT WEEK. GFS REMAINS FURTHER WEST AND
SLOWER WHILE THE ECMWF IS FURTHER EAST /ALTHOUGH LATEST RUN IS
WEST OF PREVIOUS RUN/ AND FASTER. NEITHER 00Z SOLUTION BRINGS
IMPACTS TO THE CWA...BUT REGARDLESS...STILL FAR OUT IN THE
FORECAST AND ITS SOMETHING THAT NEEDS TO BE WATCHED AS WE HEAD
INTO NEXT WEEK.
11
&&
.AVIATION...
06Z UPDATE...
BACK DOOR FRONT WILL ENTER NORTHEAST GA BY 09Z... THEN PUSH SOUTH OF
ATL BY 12-14Z... THEN SOUTH OF CSG AND MCN BY 15-16Z THIS MORNING.
EXPECT WINDS TO SHIFT NE AHEAD OF THE FRONT THEN MID LEVEL CIGS TO
SPREAD IN WITH OR JUST BEHIND THE FRONT. COULD SEE OCNL LOWER MVFR
CIGS WITH ANY ASSOCIATED MORNING SHOWERS ACTIVITY. MODELS CONTINUE
TO SUGGEST THE POTENTIAL FOR ISOLATED TO SCATTERED THUNDERSTORMS
BEHIND THE FRONT... SO WILL CONTINUE TO SHOW TEMPO 18-22 -TSRA...
BUT THINKING THE MORE WIDESPREAD CONVECTION WILL BE SHOWERS...
EXCEPT MAYBE DOWN AROUND MCN AND CSG. WINDS STAY NORTHEAST AROUND
10-12KT TODAY WITH HIGHER GUSTS TO AROUND 16-18KTS. MID LEVEL CIGS
ARE EXPECTED TO LOWER TO MVFR LEVELS TONIGHT AROUND 09Z.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON WINDS... MEDIUM CONFIDENCE ON ALL OTHER ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 74 89 70 87 / 40 60 40 10
ATLANTA 76 90 72 86 / 30 60 40 20
BLAIRSVILLE 68 83 66 82 / 40 60 40 20
CARTERSVILLE 73 91 72 87 / 30 60 40 20
COLUMBUS 79 95 74 88 / 20 60 40 20
GAINESVILLE 73 87 70 84 / 40 60 40 20
MACON 77 94 72 88 / 20 60 40 10
ROME 74 92 73 88 / 40 60 40 20
PEACHTREE CITY 75 91 72 87 / 20 60 40 20
VIDALIA 77 93 72 89 / 20 60 50 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
&&
$$
SHORT TERM...NLISTEMAA/39
LONG TERM....SNELSON
AVIATION...39
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1253 AM CDT SUN AUG 24 2014
.DISCUSSION...
326 PM CDT
A PERSISTENT UPPER RIDGE THAT HAS BEEN SITTING OVER THE MIDWEST WILL
GRADUALLY FLATTEN AND BE PUSHED TO THE SOUTH AND EAST OVER THE NEXT
FEW DAYS...BUT NOT UNTIL THIS COMING THURSDAY OR FRIDAY WILL IT
AND ITS SURFACE MANIFESTATION BE PUSHED FAR ENOUGH AWAY TO ALLOW A
SURGE OF COOLER AND DRIER AIR INTO THE LOCAL AREA. UNTIL MIDWEEK
THE WARM AND HUMID AIRMASS WILL REMAIN IN PLACE...SUPPORTING
ONGOING CHANCES OF SHOWERS AND THUNDERSTORMS...WITH HEAT INDICIES
ON MONDAY APPROACHING THE LOCAL HEAT ADVISORY CRITERIA OF 105F.
POTENT SHORTWAVES LIFTING THROUGH THE TOP OF THE RIDGE TODAY HAVE
SUPPORTED A BROAD CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN. MODELS
ARE IN REASONABLE AGREEMENT IN SHOWING SIMILAR BUT SOMEWHAT WEAKER
WAVES LIFTING THROUGH AGAIN TOMORROW...THOUGH THE FOCUS IS A BIT
FARTHER WEST. ALSO...MORE PRONOUNCED WARM ADVECTION AROUND THE
850MB LEVEL LOCALLY IS EXPECTED TO INHIBIT CONVECTIVE DEVELOPMENT
COMPARED TO WHAT WE SAW TODAY...AND THE INCREASED CLOUDINESS FROM
THE SHORTWAVES SHOULD ALSO SERVE TO LIMIT THE DEGREE OF AFTERNOON
SURFACE HEATING.
AS A WEAK SURFACE TROUGH APPROACHES SLOWLY FROM THE NORTHWEST...TSRA
CHANCES CREEP BACK UP AGAIN MONDAY AND TUESDAY ALONG WITH...AND
BECAUSE OF...MORE PRONOUNCED LOW LEVEL HEATING WITH SOUTH TO
SOUTHWEST WINDS SUPPORTING BETTER MIXING AND A WEAKER CAP ALOFT.
MONDAY LOOKS TO BE WARMER THAN EITHER SUNDAY OR TUESDAY...AND
AMPLE MOISTURE WILL SUPPORT HEAT INDICIES BETWEEN 100 AND
105...NEAR THE CRITERIA FOR A HEAT ADVISORY. IT IS A BIT EARLY TO
HOIST A HEADLINE BUT THIS WILL CONTINUE TO BE MONITORED.
BY WEDNESDAY THE TROUGH JUST TO OUR NORTHWEST WILL HAVE EVOLVED TO A
WARM FRONT ASSOCIATED WITH A LOW OVER THE PLAINS. THIS LOW THEN
LIFTS ALONG THIS BOUNDARY AND SETTLES OVER THE LOCAL AREA ON
THURSDAY BEFORE CONTINUING OFF TO THE EAST ON FRIDAY. HIGH
TEMPERATURES BOTH WEDNESDAY AND THURSDAY COULD BE TRICKY DEPENDING
ON WHERE THE SURFACE BOUNDARIES SET UP...BUT INCREASED CLOUDINESS
AND ONGOING TSRA CHANCES SHOULD KEEP THOSE DAYS COOLER THAN MONDAY
AND TUESDAY. THE MORE SIGNIFICANT CHANGE OF AIRMASS WILL THEN BE
IN PLACE ACROSS THE ENTIRE AREA BY FRIDAY AND SATURDAY...THOUGH
THE ECMWF IS A BIT SLOWER THAN THE GFS IN PUSHING THIS BOUNDARY
THROUGH.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* POTENTIAL FOR IFR CIGS/VSBY THROUGH DAYBREAK.
* EAST TO SOUTHEAST WINDS THROUGH EARLY AFTERNOON WITH A SHIFT T0
NORTHEAST POSSIBLE WITH PASSAGE OF LAKE BREEZE. SPEEDS MAY REACH
10 KT OR SO THIS AFTERNOON.
* LOW CHANCE FOR ISOLD TSRA OVERNIGHT AND AGAIN THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER THE NORTHERN PLAINS EARLY THIS MORNING IS
CONTINUING TO LIFT NORTHWARD INTO CANADA WHILE HIGH PRESSURE
SETTLES SOUTHWARD INTO NEW ENGLAND. SURFACE WINDS HAVE DECOUPLED
IN THE LIGHT GRADIENT ALLOWING FOR LIGHT AND VARIABLE OR EVEN CALM
OBSERVATIONS. CIG/VSBY TRENDS WILL BE THE BIGGEST CHALLENGE THROUGH
DAYBREAK GIVEN THE LIGHT FLOW AND ABUNDANT MOISTURE. AN EXPANSIVE
CIRRUS SHIELD OVERHEAD MAY BE LIMITING FOG/STRATUS DEVELOPMENT AT
THE CURRENT TIME. EXPECT THAT THE TERMINALS WILL SEE SOME DEVELOP
BUT HAVE SLOWED THE ONSET BY A FEW HOURS AND MAINTAINED THE
SCATTERING/LIFTING DURING THE MID MORNING. WINDS WILL GENERALLY BE
SOUTHEASTERLY TODAY WITH SPEEDS COMING UP MODESTLY. A LAKE BREEZE
BOUNDARY IS EXPECTED TO DEVELOP AND MOVE INLAND THIS AFTERNOON SO
WILL CONTINUE WITH A SHIFT TO EAST WINDS AT ORD/MDW AND INDICATE A
NORTHEAST WIND AT GYY. SPEEDS MAY COME UP TO AROUND 10 KT BEFORE
DIMINISHING THIS EVENING. THUNDERSTORM CHANCES REMAIN FAIRLY LOW
WITH A CHANCE FOR A ROGUE CELL TONIGHT AND POSSIBLY A FEW CELLS
THIS AFTERNOON AS A MID/UPPER LEVEL TROUGH MOVES THROUGH.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW-MEDIUM CONFIDENCE IN CIGS/VSBY TIMING THIS MORNING.
* MEDIUM CONFIDENCE IN LAKE BREEZE REACHING ORD/MDW THIS
AFTERNOON. MEDIUM CONFIDENCE EASTERLY WINDS WILL INCREASE TO
AROUND 10 KT WITH PASSAGE.
* HIGH CONFIDENCE THAT TSRA POTENTIAL IS LOW.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF TSRA.
TUESDAY...CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
THURSDAY...CHANCE OF TSRA.
FRIDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1106 PM CDT Sat Aug 23 2014
.UPDATE...
ISSUED AT 855 PM CDT SAT AUG 23 2014
Storms have finally pushed southeast of our area early this
evening as the outflow boundary from this morning`s convection
ignited scattered storms across the I70 corridor as it edged
southeast during the afternoon. The air mass from Springfield
south to I70 was characterized by surface base capes of 5500-6000
J/KG but very weak winds aloft, so storms developed quickly but
moved very slowly along the boundary. 00z ILX and DVN soundings
showing the stabilizing effect from the storms that moved across
the area this morning and early this afternoon with capes quite a
bit lower than analyzed across the south with a fairly significant
cap in place.
Looking at the latest HRRR model suggests very little threat for
rain overnight with the axis of the low level jet and 850 mb moisture
convergence further to our west across Iowa into northwest Illinois.
Will remove the slight chances over the east and southeast as the
rain has shifted out of our area. Will keep the threat for fog going
as it appears tonight will be a very similar setup to what occurred
over parts of central and east central Illinois last night. Very
light winds and copious amounts of moisture in the low levels should
lead to patchy fog development after midnight.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Southern flank of morning thunderstorm complex continues to impact
the northeast KILX CWA around Champaign and Danville this afternoon,
with only minimal development noted further southwest along the
trailing outflow boundary. Models have once again handled the
situation poorly, with the NAM/GFS being too aggressive with
convective development and the HRRR keeping system too far north.
Think storms will gradually push into Indiana over the next 3 to 4
hours, followed by only isolated convection across the eastern CWA
early this evening. Once daytime instability wanes, dry conditions
are expected overnight. With clearing skies and light winds, fog
will likely develop late tonight into Sunday morning. Forecast
soundings and numeric guidance both suggest at least some
restriction to visibilities, and based on what happened last night,
think its prudent to carry patchy fog late tonight. Upper ridge
axis will continue to control the weather across central Illinois on
Sunday, providing hot and mainly dry conditions. Some models are
hinting that widely scattered convection may fire along the Indiana
border by afternoon, but think this is a bit overdone. Will only
maintain slight chance PoPs across the far southeast, with dry
weather elsewhere. High temperatures will reach the lower 90s,
resulting in heat index values of 100 to 105 degrees.
&&
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Medium range models are generally in good agreement for the first
few days of next week, then they digress pretty rapidly for two
reasons. First is the difference in solutions involving the speed
and strength of the upper level trough expected to move from the
Rockies to Midwest. This looks like it is being caused by the second
main difference, which is a lot of uncertainty with the speed and
motion of a pending tropical system in the western Atlantic. These
tropical systems tend to back up the west-east progression of
weather systems in the middle U.S. Thus, there is a greater than
normal level of uncertainty with the forecast for Wednesday through
the end of the week.
In the nearer term period for Monday and Tuesday, it appears likely
that the hot and humid conditions will continue. Monday could end up
being one of the hottest days with highs from 93-95 in central IL
and 91-93 in east/southeast IL. This will keep heat index values in
the 105-108 range in much of central and southeast IL, so will keep
the heat advisory going through Monday. Considered extending the
advisory into Tuesday, but will hold off for now since there is some
level of uncertainty as to the amount of increasing cloudiness
during the day, which could keep temps down just a bit.
The movement of a cold front, associated with aforementioned
approaching upper level trough, will really depend on the east coast
tropical system. The most likely scenario, which is not really
handled very well by any model, is that the front will slowly
approach - and may even get hung up in central IL for a day or two.
Thus, will stick with a prolonged period of scattered showers/t-storms
Wednesday into Friday. The cloudiness associated with this rain
potential will keep temperatures down in the 80s, ending the stretch
of hot weather. However, longer term trends indicate the possibility
that we may see a return to very warm conditions for Labor Day
weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1100 PM CDT SAT AUG 23 2014
Band of MVFR cigs (2000-3000 feet) extended from parts of central
thru west central Illinois and seems to be drifting slowly north
late this evening. Large MCS to our south will continue to drift
away from our area overnight with the main forecast concern being
extent of fog and low cigs acrs our area. Large area of thick cirrus
from the convection to our south and some of the lower clouds mentioned
above may influence how widespread the fog will get overnight.
Forecast soundings suggest the moisture in the 2000-3000 foot range
should become more scattered with time overnight with cirrostratus
clouds thinning later tonight so will continue from the previous
forecast in keeping the threat for at least MVFR if not IFR cigs/vsbys
in a few locations in the 09z-13z time frame.
What fog we do see late tonight should lift by 14 or 15z Sunday morning
with a mostly scattered cumulus deck developing by late morning or
early afternoon with soundings indicating cloud bases around 3000-3500
feet, which should dissipate quickly by evening. Surface winds will
be from an easterly direction overnight with speeds of 4 to 8 kts, and
then from a southeast to south direction on Sunday at 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056-
061>063-066>068-071>073.
HEAT ADVISORY from Noon Sunday to 7 PM CDT Monday FOR ILZ036-040-
041.
&&
$$
UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...MILLER
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
238 AM CDT Sun Aug 24 2014
...Updated long term section...
.SHORT TERM...(Today and tonight)
ISSUED AT 201 AM CDT SUN AUG 24 2014
Models are in good agreement with moving a weak cold front across
west central and north central Kansas this morning. This surface
boundary will then become stationary across southwest and north
central Kansas by the early afternoon. A warm 850mb thermal ridge
axis was located ahead of this surface boundary at 00z Sunday and
both the NAM and GFS indicated a +1 to +2C 24 hour 850 temperature
change will occur from 00z Sunday to 00z Monday ahead of this
frontal boundary, mainly across south central Kansas. Northwest of
this frontal boundary the 850mb temperatures cool roughly 2 to 3C
from 00z Sunday to 00z Monday. Based on this expected trend and
where this surface boundary will be located late today will favor
highs at or a degree or two warmer than yesterday southeast of this
front. Highs today northwest of this front will be slightly cooler
and generally will be in the lower 90s.
Widely scattered thunderstorms will be possible late day/early
evening near and east of the surface boundary given improving
moisture and afternoon instability. After 00z Monday an upper
level jet will move out of the Rockies and across western Nebraska
which will place west central and north central Kansas near the
right entrance region of the upper level jet by 06z. As the upper
level dynamics improves across northern Kansas early tonight the
850mb winds from the NAM and GFS both suggested a +40kt low level
jet will be developing across western Kansas. Based on where the
nose of the low level jet will be located between 06z and 12z
Monday along with upslope flow across northeast Colorado/northwest
Kansas, location of the +12c to +14c 700mb temperature gradient,
and a 925mb to 850mb thta-e ridge axis across northern Kansas
overnight will continue to favor increasing chances of convection
across north central Kansas during the overnight period as evening
thunderstorms over south central Kansas tapers off.
.LONG TERM...(Monday through Saturday)
ISSUED AT 237 AM CDT SUN AUG 24 2014
Monday looks to be warm once again with temperatures reaching into
the mid to upper 90s with a few 100s across south central Kansas. A
few lingering showers will be possible across central and west
central Kansas in the morning with partly cloudy skies expected by
the afternoon. This will be short lived as an upper level shortwave
moves out from Colorado and into the Central High Plains Monday
night increasing cloudiness across the CWA. A chance of
thunderstorms will exist from late afternoon into the overnight
period, mainly across northern Kansas as well as central and west
central Kansas. Lows Monday and Tuesday mornings look to range from
the mid 60s across the KS/CO border to lower 70s across south
central Kansas. Meanwhile, an upper level low will be digging into
the Pacific northwest Monday before weakening into a opened
shortwave and ejecting eastward across the Rockies Tuesday then into
the Central Plains Wednesday into Thursday. Latest model runs have
this system moving slightly slower than previous as well as tracking
a little farther north. Nevertheless, thunderstorms look favorable
Tuesday afternoon through Thursday afternoon as this system
approaches and moves across Nebraska. The best chances of
precipitation will be across northern Kansas and the I-70 corridor
with lesser chances the farther south you go. A few lingering
showers may be possible across south central Kansas Thursday night,
otherwise expect decreasing cloudiness. Highs during this timeframe
look to decrease from the 90s Tuesday to 80s Wednesday through
Friday. Lows look to be in the 60s to lower 70s Wednesday morning
with 60s expected into this weekend. The remainder of the forecast
period looks dry as an upper level ridge builds across the western
United States. Skies will be mostly clear during this timeframe with
highs rebounding into the 90s by Saturday. Lows will remain in the
60s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1204 AM CDT SUN AUG 24 2014
A cold front will move into western and north central Kansas this
morning where it will become nearly stationary during the
afternoon hours. Based on 03z verification of this surface
boundary the NAM and HRRR had a decent handle with the movement of
this front so stay close to timing of frontal passage/wind shift
as it moves across the GCK and HYS areas late this morning. At
this time it appears this boundary will stay just west of DDC so
south/southwest winds at 10 to 15 knots will continue at DDC
through Sunday evening. BUFR soundings and HRRR indicating cloud
bases across western Kansas will be mainly at or above the 10000ft
AGL level tonight and Sunday so VFR conditions can be expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 98 69 98 71 / 10 20 20 30
GCK 94 67 97 70 / 10 10 30 40
EHA 94 66 96 68 / 10 10 20 20
LBL 97 67 97 70 / 10 10 20 20
HYS 95 67 97 70 / 10 20 30 40
P28 100 73 100 74 / 20 20 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Hovorka_42
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
206 AM CDT Sun Aug 24 2014
...Updated short term discussion...
.SHORT TERM...(Today and tonight)
ISSUED AT 201 AM CDT SUN AUG 24 2014
Models are in good agreement with moving a weak cold front across
west central and north central Kansas this morning. This surface
boundary will then become stationary across southwest and north
central Kansas by the early afternoon. A warm 850mb thermal ridge
axis was located ahead of this surface boundary at 00z Sunday and
both the NAM and GFS indicated a +1 to +2C 24 hour 850 temperature
change will occur from 00z Sunday to 00z Monday ahead of this
frontal boundary, mainly across south central Kansas. Northwest of
this frontal boundary the 850mb temperatures cool roughly 2 to 3C
from 00z Sunday to 00z Monday. Based on this expected trend and
where this surface boundary will be located late today will favor
highs at or a degree or two warmer than yesterday southeast of this
front. Highs today northwest of this front will be slightly cooler
and generally will be in the lower 90s.
Widely scattered thunderstorms will be possible late day/early
evening near and east of the surface boundary given improving
moisture and afternoon instability. After 00z Monday an upper
level jet will move out of the Rockies and across western Nebraska
which will place west central and north central Kansas near the
right entrance region of the upper level jet by 06z. As the upper
level dynamics improves across northern Kansas early tonight the
850mb winds from the NAM and GFS both suggested a +40kt low level
jet will be developing across western Kansas. Based on where the
nose of the low level jet will be located between 06z and 12z
Monday along with upslope flow across northeast Colorado/northwest
Kansas, location of the +12c to +14c 700mb temperature gradient,
and a 925mb to 850mb thta-e ridge axis across northern Kansas
overnight will continue to favor increasing chances of convection
across north central Kansas during the overnight period as evening
thunderstorms over south central Kansas tapers off.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 254 PM CDT SAT AUG 23 2014
An upper level trough is forecast to move from the Western States on
Monday, then into the Intermountain West on Tuesday, then into the
Plains on Wednesday, with an associated cold front. The small
chances for thunderstorms will continue ahead of the cold front,
then increase with and just ahead of the front on Wednesday, with
lingering chances into Friday morning with the upper trough. The
upper trough then moves east of the Central Plains on Friday with
shortwave ridging and warming.
Daytime highs will be warm, ahead of the cold front, on Monday and
Tuesday in the mid to upper 90s, then cool into the 80s into Friday,
then back to around 90 by the Weekend. Overnight lows continue mild
around 70 on Sunday night into Tuesday night, then dip into the mid
60s into the Weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1204 AM CDT SUN AUG 24 2014
A cold front will move into western and north central Kansas this
morning where it will become nearly stationary during the
afternoon hours. Based on 03z verification of this surface
boundary the NAM and HRRR had a decent handle with the movement of
this front so stay close to timing of frontal passage/wind shift
as it moves across the GCK and HYS areas late this morning. At
this time it appears this boundary will stay just west of DDC so
south/southwest winds at 10 to 15 knots will continue at DDC
through Sunday evening. BUFR soundings and HRRR indicating cloud
bases across western Kansas will be mainly at or above the 10000ft
AGL level tonight and Sunday so VFR conditions can be expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 98 69 98 71 / 10 20 20 30
GCK 94 67 97 70 / 10 10 30 40
EHA 94 66 96 68 / 10 10 20 20
LBL 97 67 97 70 / 10 10 20 20
HYS 95 67 97 70 / 10 20 30 40
P28 100 73 100 74 / 20 20 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Kruse
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1207 AM CDT Sun Aug 24 2014
...Update synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1204 AM CDT SUN AUG 24 2014
At 00z Sunday a 500mb low was centered over western Wyoming and a
300mb +70 knot jet streak was located near the based of this upper
level system and stretched from northwest Colorado to southwest
Idaho. Further northwest a +90 knot 300mb jet extended from north
to south along the coast of British Columbia. A 700mb low was
located over eastern Montana with the 700mb trough extending south
of this low into eastern Colorado. East of this trough axis 700mb
temperatures at 00z Sunday ranged from 10c at North Platte to +12c
at Amarillo. Also east of the 700mb trough axis a wedge of higher
700mb dew points extended from the Texas panhandle into north
central Kansas. At the surface an area of low pressure was located
over southeast Colorado and a cold front extended northeast of
this surface low into southwest Nebraska. A warm 850mb thermal
ridge axis was located just ahead of this cold front. 850mb
temperatures at 00z Sunday along this ridge axis ranged from +23c
at Omaha to +27c at Dodge City to +28c at Amarillo.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 339 PM CDT SAT AUG 23 2014
A fairly strong shortwave trough by late August standards will progress
northeastward from the Intermountain west into North Dakota by Sunday
evening. A lee trough has developed ahead of this system; but low
level moisture over western Kansas was very limited. Also, upper
level temperatures were warm (-7C at 500mb and -32C at 300mb) so
that surface based CAPE was 1000 j/kg or less. A few showers had
developed in the Texas panhandle as of 20z along a convergence
line. This activity could build northeastward into south central
and southwest Kansas late this afternoon; but any shower or
thunderstorms would be isolated. With the loss of daytime heating,
precipitation is not expected after 8 to 9 pm since elevated
instability should be located along the edge of the mid level
capping inversion, well to the north in Nebraska. South winds will
keep temperatures from falling very fast through midnight. However,
wind speeds may drop to 5 to 10 kts by 12z as a surface trough
approaches from the west, and this may allow temperatures to fall
into the 60s to near 70F from Dodge City westward, with mid 60s
near the Colorado state line.
A trailing cold front associated with the aforementioned shortwave
trough will stall out over southwestern Kansas by Sunday afternoon.
A few thunderstorms may develop again, mainly for areas south and
east of Dodge City. Surface dewpoints will be a little higher
(around 60F) so that surface based CAPE will be around 1500 j/kg.
Vertical wind shear will be weak so that severe weather is not
expected.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 254 PM CDT SAT AUG 23 2014
An upper level trough is forecast to move from the Western States on
Monday, then into the Intermountain West on Tuesday, then into the
Plains on Wednesday, with an associated cold front. The small
chances for thunderstorms will continue ahead of the cold front,
then increase with and just ahead of the front on Wednesday, with
lingering chances into Friday morning with the upper trough. The
upper trough then moves east of the Central Plains on Friday with
shortwave ridging and warming.
Daytime highs will be warm, ahead of the cold front, on Monday and
Tuesday in the mid to upper 90s, then cool into the 80s into Friday,
then back to around 90 by the Weekend. Overnight lows continue mild
around 70 on Sunday night into Tuesday night, then dip into the mid
60s into the Weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1204 AM CDT SUN AUG 24 2014
A cold front will move into western and north central Kansas this
morning where it will become nearly stationary during the
afternoon hours. Based on 03z verification of this surface
boundary the NAM and HRRR had a decent handle with the movement of
this front so stay close to timing of frontal passage/wind shift
as it moves across the GCK and HYS areas late this morning. At
this time it appears this boundary will stay just west of DDC so
south/southwest winds at 10 to 15 knots will continue at DDC
through Sunday evening. BUFR soundings and HRRR indicating cloud
bases across western Kansas will be mainly at or above the 10000ft
AGL level tonight and Sunday so VFR conditions can be expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 98 71 96 / 20 20 20 30
GCK 67 96 70 95 / 10 20 20 30
EHA 66 95 68 93 / 10 20 20 30
LBL 67 96 70 95 / 20 20 20 30
HYS 67 96 71 95 / 20 30 30 30
P28 73 98 75 99 / 20 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Finch
LONG TERM...Kruse
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS PADUCAH KY
333 AM CDT Sun Aug 24 2014
.SHORT TERM...
Issued at 333 AM CDT Sun Aug 24 2014
There is very little change in the synoptic pattern or the
forecast this forecast cycle. The main issues continue to be the
timing and location of convection...as well as their impacts on
temps/dew points/heat indices.
In the near term...an outflow boundary from last evenings mcs
over the Lower Ohio Valley made it as far southwest as the
Missouri Bootheel by 08z. This mcs and its outflow has stabilized
the air mass for the time being...especially east of the
Mississippi River.
The latest model data /especially the rap/ still indicates the
surface wind flow will become easterly during the day today. The
rap indicates a surface convergence zone along the leading edge of
this easterly push. The RAP model pools moisture along this
boundary...which results in high dew points and an axis of strong
instability by this afternoon. This axis extends from southern
Illinois into western Kentucky by early this afternoon. Based on
this data...will expand slight chance pops as far west as the
Mississippi River counties again today. The coverage of convection
should be rather isolated...given drier mid level air
overspreading the Mississippi Valley on water vapor imagery.
Heat indices will again reach 105 in most areas today. Even where
clouds were widespread on Saturday...heat indices still exceeded
105 due to extremely high dew points around 80. High temps should
be very similar to those on Saturday...except where localized
convection occurs.
The daily potential for isolated convection should be suppressed
further to the south and east Monday and Tuesday as the mid level
ridge axis establishes itself along the Ohio Valley. Will keep
slight chance pops mainly southeast of the Ohio River both days.
As for temps...will generally follow the hotter gfs mos for both
Monday and Tuesday. Some of the model guidance continues to lower
temps slightly. Given that the deep layer ridge will be positioned
nearly overhead through the period...this cooling looks suspect.
There may be a slight lowering of dew points as the low level flow
remains out of the east. This may lower heat indices a few
degrees...but they are still forecast to reach 100 to 105 Tuesday.
.LONG TERM...
Issued at 333 AM CDT Sun Aug 24 2014
Well there continues to be a rift between the GFS and ECMWF/GEM in
their 00Z runs. The trend with all of the models is slower with the
eastward movement of the western U.S. low/trough. The 00Z ECMWF is
leading the charge and tonight`s run basically builds an upper
ridge north of the trough, effectively removing it from the
westerlies. Am beginning to wonder if this system and its associated
surface boundary are ever going to reach our region.
The 00Z GFS brings the upper trough and cold front through the area
Thursday and Thursday night, and then brings drier, cooler air into
the region for Friday and next Saturday. The Canadian/GEM is a lot
closer to the ECMWF solution, but not quite as slow. Really think
the ECMWF is onto something, so will lean toward it for this
forecast.
The problem with the ECMWF and GEM solutions with respect to our
existing forecast is that they allow a significant upper trough to
dive southeast into New England by Thursday morning. That brings a
backdoor cold front southward into our northern counties late
Wednesday and Wednesday night. The front ends up draped across the
area from northwest to southeast Thursday and Friday. This leads to
a decent chance of convection both days.
The other effect of the ECMWF solution is the potential for the heat
and humidity to linger through much of the work week, if not all the
way through next Saturday. Bumped up temperatures just a bit
throughout the extended. Heat indices on Wednesday are generally at
or below 100, so there will be no need to extend the Heat Advisory
any further with this forecast package.
&&
.AVIATION...
Issued at 1130 PM CDT SAT AUG 23 2014
Convection induced by a westward moving outflow boundary at KPAH
should end by the time the 06Z TAFS begin so will have no mention
of any tsra. If we can get the clouds to clear out and the winds
to become calm for a while, we might actually get some fog to
develop. Opted to just leave the MVFR vsbys going for now since
confidence is still low whether or not it will form. Otherwise,
the rest of the overnight and into Sunday morning should be
tranquil. Plenty of instability will be present during the day on
Sunday for more isolated to scattered storms. But coverage of
storms is still unknown attm so will opt to leave any mention out
at this time. Winds will remain light and variable.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...HEAT ADVISORY until 7 PM CDT Tuesday FOR KYZ001>022.
MO...HEAT ADVISORY until 7 PM CDT Tuesday FOR MOZ076-086-087-100-
107>112-114.
IL...HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ075>078-080>094.
IN...HEAT ADVISORY until 7 PM CDT Tuesday FOR INZ081-082-085>088.
&&
$$
SHORT TERM...MY
LONG TERM....DRS
AVIATION...CW
AREA FORECAST DISCUSSION
NWS JACKSON KY
222 AM EDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 1051 PM EDT SAT AUG 23 2014
SENT OUT ONE LAST UPDATE TO THE FORECAST FOR THIS SHIFT. SHOWERS AND
STORMS OVER THE PAST HOUR OR SO HAVE MADE THEIR WAY INTO PORTIONS OF
PULASKI...WAYNE...AND MCCREARY COUNTIES...SO PRECIPITATION
PROBABILITIES AND QPF AMOUNTS DOWN THERE WERE BEEFED UP THROUGH 4 OR
5Z TONIGHT. WITH ISOLATED STORMS PUSHING SOUTHWARD TOWARD PIKE
COUNTY AND WITH OTHER ISOLATED STUFF HAVING POPPED UP AND DIED IN OUR
BLUEGRASS COUNTIES...DECIDED TO GO AHEAD AND LEAVE IN A SLIGHT CHANCE
OF SHOWERS AND STORMS FOR THE MAJORITY OF THE AREA THROUGH 12Z. THE
EXCEPTION WILL BE WAYNE COUNTY WHERE LIKELY POPS WERE INTRODUCED TO
ACCOUNT FOR THE ENHANCED SHOWER AND STORM ACTIVITY DOWN WHICH APPEARS
IS BEING DRIVEN BY OUTFLOW BOUNDARIES FROM THE STORMS ONGOING IN EAST
CENTRAL KENTUCKY. FOR FORMATION WILL STILL BE OF CONCERN TOO THROUGH
THE OVERNIGHT SO IT WAS AGAIN FEATURED IN THE FORECAST THROUGH 13Z
TOMORROW WITH LOCALLY DENSE FOG POSSIBLE IN OUR VALLEYS.
UPDATE ISSUED AT 733 PM EDT SAT AUG 23 2014
WILL BE SENDING OUT AND UPDATED ZONE FORECAST SHORTLY TO REMOVE THE
PRE FIRST PERIOD PUT IN BY THE DAY SHIFT AND TO DECREASE PRECIPITATION
CHANCES CROSS THE ENTIRE AREA FOR THE REMAINDER OF THE OVERNIGHT
PERIOD INTO EARLY TOMORROW MORNING. THE LATEST NAM12 AND HRRR MODEL
RUNS MATCH UP WELL WITH THE ISOLATED SHOWER AND STORM COVERAGE
CURRENTLY BEING OBSERVED ACROSS EASTERN KENTUCKY. BASED ON THE THE
FACT THAT MOST OF THE LONG LIVED SHOWERS AND STORMS ARE CONFINED TO
CENTRAL KENTUCKY AND WITH THEIR SLOW SOUTHWARD DIRECTION OF
MOVEMENT...AND WITH THE SUN DUE TO SET SOON...IT SIMPLY DOES NOT
APPEAR THAT WE WILL SEE MORE THAN ISOLATED SHOWERS OR STORMS ACROSS
THE MAJORITY OF THE AREA TONIGHT. THERE STILL IS A SMALL CHANCE OF
SCATTERED ACTIVITY WEST OF I75...BUT EVEN THAT IS IN QUESTION AT THIS
POINT. THE FOG FORMATION OVERNIGHT IS ON TRACK...HOWEVER...WITH CLEAR
SKIES...LIGHT WINDS...AND AMPLE SURFACE MOISTURE IN PLACE. WE WILL
STILL LIKELY SEE AREAS OF DENSE FOG LATE TONIGHT INTO EARLY TOMORROW
MORNING...WITH THE MOST FAVORED AREAS BEING OUR VALLEYS. THE NEW
FORECAST WILL REFLECT MUCH LOWER PRECIPITATION CHANCES OVERNIGHT AND
WIDESPREAD FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 350 PM EDT SAT AUG 23 2014
19Z SFC ANALYSIS SHOWS OUR CONTINUING WEATHER CHALLENGE WITH THE LOW
PRESSURE OUT TO THE WEST AND HIGH PRESSURE TO THE SOUTH. A WAVY
NORTHWEST TO SOUTHEAST FRONT EXISTS JUST NORTH OF OUR AREA.
MEANWHILE...ALOFT...A RIDGE IS FOUND THROUGH THE LOWER MIDSECTION OF
THE NATION WITH A DIGGING TROUGH MOVING INTO THE MID ATLANTIC STATES.
THIS PLACES CENTRAL AND EASTERN KENTUCKY IN THE TRACK OF ENERGY
MOVING FROM THE UPPER MIDWEST INTO THE SOUTHERN APPALACHIANS TODAY.
THESE FEATURES HAVE BEEN COMBINING LATELY TO PRODUCE CLUSTERS OF
SHOWERS AND THUNDERSTORMS GENERALLY STARTING IN THE LATE AFTERNOON
AND LASTING INTO THE EVENING. THE HIGH PW AIR IN PLACE OVER THE
AREA...ALONG WITH THE DEWPOINTS PUSHING THE MID 70S...MAKES FOR
PROLIFIC RAIN PRODUCING CELLS. AS HAS BEEN THE CASE REMAINS SO
HEADING INTO LATE AFTERNOON...THOUGH THE AXIS OF CONCERN HAS SHIFTED
SLIGHTLY WEST OWING TO THE WIGGLE OF THE RIDGE IN RESPONSE TO THE
DIGGING TROUGH. CURRENTLY SCATTERED AND ISOLATED SHOWERS/STORMS ARE
DOTTING THE CUMBERLAND VALLEY WITH SIGNS OF LARGER CLUSTERS STARTING
TO TAKE SHAPE TO THE NORTHWEST. THOUGH DELAYED A BIT BY THE LOW
STRATUS DECK FOLLOWING THE DENSE FOG THIS MORNING...TEMPERATURES HAVE
CLIMBED SMARTLY INTO THE MIDDLE AND UPPER 80S THROUGH THE AREA AND
WITH SUCH HIGH DEWPOINTS ARE YIELDING HEAT INDICES IN THE 95 TO 100
DEGREE RANGE. WINDS HAVE BEEN MAINLY LIGHT AND VARIABLE THROUGH THE
AREA.
THE MODELS ARE ALL IN PRETTY GOOD AGREEMENT ALOFT WITH THE WIGGLE
WEST AND THEN BACK EAST OF THE UPPER RIDGE INTO MONDAY MORNING.
SHORTWAVE ENERGY MOVING SOUTH BETWEEN THE UPPER SYSTEMS WILL PASS
THROUGH CENTRAL AND EASTERN KENTUCKY TONIGHT WITH ONLY WEAKER PACKETS
FORESEEN THROUGH THE REST OF THE WEEKEND. GIVEN THE AGREEMENT OF THE
MODELS AND THE SMALLER SCALE NATURE OF CONVECTIVE ACTIVITY OF THIS
REGIME HAVE AGAIN FAVORED THE HRRR AND NAM12 THROUGH THE FIRST 18 TO
36 HOURS AND A MODEL CONSENSUS AFTER THAT INTO MONDAY MORNING.
SENSIBLE WEATHER WILL FEATURE ISOLATED AND SCATTERED CONVECTION
AROUND EAST KENTUCKY THROUGH THE NEXT SEVERAL HOURS WITH AN
DECENT POTENTIAL EVOLUTION OF STORMS INTO A LARGER SYSTEM LATER IN
THE FIRST PART OF THE EVENING SOMEWHERE TO THE NORTHWEST. THE
INGREDIENTS ARE THERE FOR ANOTHER ROUND OF SUCH STORMS AND THE
EXCESSIVE RAINFALL THEY PRODUCE. STILL THE BEST INDICATIONS ARE THAT
THE WORST OF ANY SUCH DEVELOPMENT WILL JUST BRUSH OUR SOUTHWESTERN
COUNTIES WHERE WE ARE NOT QUITE AS SATURATED AS THE EAST. THIS IS
GOOD NEWS...BUT GIVEN THE LOW FFG IN THE EAST JUST ABOUT ANY HEALTHY
STORM THERE WILL PROMPT FLASH FLOODING CONCERNS. WITH THE STILL HIGH
PWS AND INSTABILITY ACROSS THE ENTIRE AREA CANNOT CALL ANY PLACE FREE
OF LOCALIZED FLASH FLOOD CONCERNS. THE ACTIVITY IS EXPECTED TO DIE
DOWN LATER THIS EVENING AND WHEN COMBINED WITH AT LEAST PARTIAL
CLEARING WILL LIKELY BRING ABOUT ANOTHER BLANKET OF FOG BECOMING
DENSE IN AREAS TOWARD DAWN. WILL HIT THIS...IN ADDITION TO THE
STORM/FLOOD CONCERNS...HARD IN THE HWO. ONCE THE FOG BURNS OFF ON
SUNDAY...PARTLY SUNNY SKIES WILL AGAIN BUILD THE HEAT AND INSTABILITY
THROUGH THE AREA WHILE LOWER PWS FOR MUCH OF THE AREA WILL LIMIT TO A
SMALLER EXTENT FLASH FLOOD CONCERNS. EXPECT SOME COOLER AND...MORE
IMPORTANTLY...DRIER AIR TO MAKE IT INTO THE EAST BY EVENING AS A BACK
DOOR COLD FRONT PUSHES WEST THROUGH THE AREA ALLOWING SOME LOWS
CLOSER TO NORMAL FOR THIS TIME OF YEAR IN THE FAR EAST BY DAWN
MONDAY. AGAIN PATCHY FOG WILL BE A CONCERN DEPENDING ON THE RAINS
OF THE PREVIOUS DAY AND CLEARING THAT NIGHT.
STUCK WITH THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND SUNDAY
NIGHT. AS FOR POPS...ENDED UP CLOSER TO THE WETTER MET GUIDANCE
TONIGHT AND THEN NEARER THE MAV NUMBERS FOR THE REST OF THE SHORT
TERM PORTION OF THE FORECAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 239 PM EDT SAT AUG 23 2014
STRONG RIDGING WILL DOMINATE THE EASTERN CONUS THROUGH NEXT WEEK
WITH SUMMER-LIKE WEATHER CONTINUING. FORTUNATELY...WITH A STRONGER
CAP PRESENT...CONVECTION WILL BE HELD MORE AT BAY. CANNOT RULE OUT A
STRAY AFTERNOON SHOWER OR STORM EACH DAY...BUT SHOULD BE NOTHING
LIKE WE HAVE SEEN LATELY. PLANNING TO GO WITH A DIURNAL TREND WITH
POPS THROUGH THE END OF THE PERIOD WITH POPS PEAKING EACH AFTERNOON
WITH MAXIMUM HEATING/INSTABILITY. A SURFACE TROUGH MAY APPROACH FROM
THE WEST EARLY NEXT WEEKEND...BUT A TROPICAL SYSTEM DEVELOPING OVER
THE ATLANTIC BASIN...MAY HAVE A TENDENCY TO SLOW DOWN THE
ADVANCEMENT OF THIS FEATURE UNTIL SOMETIME LATE IN THE WEEKEND OR
THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 222 AM EDT SUN AUG 24 2014
THE MAIN CONCERN DURING THIS TAF PERIOD CONTINUES TO BE THE OVERNIGHT
FOG DEVELOPMENT...OR POSSIBLE LACK THEREOF. A WEAK LOW LEVEL
CIRCULATION...A WEAK BOUNDARY TO OUR WEST...AND GOOD MOISTURE
AVAILABILITY HAS LED TO SHOWERS ACROSS MUCH OF CENTRAL KY...AND A
HIGH CLOUD DECK CONSUMING MUCH OF KY. THE SHOWERS ARE MAINLY
AFFECTING THE FAR SW COUNTIES IN THE CWA...INCLUDING KSME...AND ARE
SHOWING SIGNS OF WEAKENING. EXPECT FEW IMPACTS FROM THESE SHOWERS AT
KSME OTHER THAN A LOW CLOUD DECK FOR THE NEXT FEW HOURS.
OTHERWISE...THE INFLUX OF CLOUDS HAS SO FAR HAMPERED FOG DEVELOPMENT
AT ALL OTHER TAF SITES EXCEPT FOR KSJS WHERE FOG HAD DEVELOPED
BEFORE THE CLOUDS MOVED IN THIS EVENING. FOG WILL CONTINUE TO FLUCTUATE
IN AND OUT OF AIRPORT MINS AT KSJS THROUGHOUT THE NIGHT...BUT SHOULD
ULTIMATELY REMAIN IN PLACE THROUGH DAYBREAK. ELSEWHERE...EXPECT FOG
TO STAY IN THE VALLEYS OVERNIGHT...THEN LIFT IN THE EARLY MORNING
HOURS AND AFFECT TAF SITES BEFORE BURNING OFF SHORTLY AFTER BETWEEN 8
AND 10AM. SUNSHINE AND SCT DIURNALLY DRIVEN MID LEVEL CLOUDS ARE
EXPECTED DURING THE DAY TOMORROW. THERE IS THE POTENTIAL FOR
SCATTERED AFTERNOON CONVECTION AS WELL...BUT UNTIL STORMS
DEVELOP...CONFIDENCE FOR IF AND WHEN THE STORMS WOULD AFFECT THE TAF
SITES IS TOO LOW TO WARRANT MENTION IN TAFS AT THIS TIME.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
603 AM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE SOUTH OF THE AREA AND REMAIN OVER
SOUTHERN NEW ENGLAND THROUGH TUESDAY. A COLD FRONT WILL MOVE
THROUGH ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
555 AM UPDATE...
UPDATED TO INCREASE SKY COVER FOR THIS MORNING INTO EARLY
AFTERNOON. ALSO, GOT RID OF FOG IN NORTHERN MAINE WHERE THE MID
LEVEL CLOUD DECK EXISTS. AT 6 AM, MID LEVEL CLOUD DECK EXISTS FROM
HOULTON NORTH, AND IS MOVING SOUTHWEST. NO MODELS HAD A HANDLE ON
THIS CLOUD DECK EARLIER TONIGHT. RAP AND NAM NOW HAVE A REASONABLE
HANDLE ON THE CLOUD DECK AND USED A BLEND OF THEM FOR THE DAY,
WHICH MAKES FOR MOSTLY CLOUDY SKIES THIS MORNING FROM ROUGHLY
MILLINOCKET NORTHEAST. SKIES WILL BECOME PARTLY CLOUDY LATER THIS
AFTERNOON OVER THE NORTH. THE INCREASED CLOUDS MAY KEEP TEMPS DOWN A
BIT, BUT OPTED TO LEAVE THEM AS IS FOR NOW.
PREVIOUS DISCUSSION...
ANOTHER QUIET DAY TODAY WITH JUST ISOLATED AFTERNOON SHOWERS
MAINLY FROM THE CENTRAL HIGHLANDS EAST TO AROOSTOOK COUNTY WHERE
THERE IS THE BEST LOW LEVEL CONVERGENCE. THERE IS ACTUALLY A FAIR
AMOUNT OF CAPE TO WORK WITH, BUT WITH THE UPPER RIDGE ALOFT AND
STRONG INVERSION AROUND 700 MB, IT`S GOING TO BE TOUGH TO REALIZE
MUCH CONVECTION. FELT ISOLATED SHOWERS WAS THE BEST COMPROMISE
APPROACH.
TEMPERATURES WILL CONTINUE TO BE WARMER THAN THE PREVIOUS DAY,
WITH HIGHS MAINLY IN THE LOWER 80S. WITH THE FAIRLY LIGHT PRESSURE
GRADIENT AND SUBSTANTIAL HEATING OF THE LAND, EXPECT A DECENT SEA
BREEZE, WHICH IS RESOLVED IN THE WIND GRIDS AND TEMPERATURE CURVE
WITH TEMPS FALLING LATE AFTERNOON NEAR THE COAST.
QUIET NIGHT TONIGHT WITH MOSTLY CLEAR SKIES AND MILD TEMPERATURES.
DO NOT EXPECT MUCH RADIATION FOG, AS THERE APPEARS TO BE A BIT
MORE LOW LEVEL WIND THAN PREVIOUS NIGHTS WHICH COULD KEEP FOG AWAY.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY WILL BE SUNNY AND VERY WARM WITH HIGHS IN THE MID TO UPPER
80S FOR MOST LOCATIONS. A STRONG UPPER LEVEL RIDGE WILL DOMINATE
AREA WEATHER INTO TUESDAY NIGHT. LOWS MONDAY NIGHT WILL ONLY DROP
TO AROUND 60F AND TEMPERATURES ON TUESDAY WILL SHOOT UP TO THE
UPPER 80S WITH AN UPTICK IN HUMIDITY. A COLD FRONT WILL EASE
SOUTHWARD THROUGH QUEBEC TUESDAY NIGHT AND PROVIDE THE CHANCE OF A
THUNDERSTORM TOWARDS THE ST JOHN VALLEY LATER TUESDAY NIGHT WITH
ELEVATED INSTABILITY THROUGH THE NIGHT. LOWS WILL ONLY BE IN THE
LOW TO MID 60S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY WILL THE DAY THAT THE COLD FRONT CROSSES THE FORECAST
AREA FROM NORTH TO SOUTH. THE TIMING OF ITS CROSSING PRESENTS THE
BEST OPPORTUNITY FOR STRONG STORMS SOUTH OF HOULTON. THE SOUTHERN
HALF OF THE FORECAST AREA WILL HAVE THE GREATEST SURFACE-BASED
CAPE WITH HIGHS APPROACHING 90F. DEWPOINTS RISING TO THE MID 60S
AHEAD OF THE FRONT IN THE SOUTHERN HALF OF THE FORECAST AREA WILL
ADD MORE FUEL. THUNDERSTORMS THAT DEVELOP COULD REACH 35K TO 40K
FT IF THEY CAN OVERCOME THE CAP NEAR H700. THE MOST LIKELY RISK WILL
BE STRONG WINDS AND HAVE ADDED GUSTY WIND ENHANCED WORDING FOR
NOW. FOR NORTHERN AROOSTOOK...THE FRONT WILL CROSS TOO EARLY IN THE
DAY AND APPEARS TO MITIGATE THE SEVERE RISK. HIGHS THERE WILL BE
IN THE LOWER 80S. SHOWERS AND THUNDERSTORMS WILL WIND DOWN
WEDNESDAY EVENING FOR BANGOR AND THE DOWN EAST REGION AND COOLER
AIR WILL GRADUALLY FILTER INTO THE REGION LATER IN THE NIGHT INTO
THURSDAY. THURSDAY WILL BE MUCH COOLER WITH HIGHS REACHING AROUND
80F DOWN EAST WITH A NORTHWEST FLOW. FURTHER NORTH IN AROOSTOOK
COUNTY...HIGHS WILL BE CLOSER TO 70F WITH WIDESPREAD CUMULUS
LIMITING SUNSHINE AND A FEW SHOWERS IN THE NW FLOW. A PLEASANTLY
COOL NIGHT APPEARS ON TAP FOR THURSDAY NIGHT WITH LOWS IN THE
UPPER 40S TO LOW 50S. CANADIAN HIGH PRESSURE WILL BE CENTERED
OVER THE REGION ON FRIDAY WITH HIGHS IN THE 70S AND LOW HUMIDITY.
THE HIGH WILL QUICKLY MOVE EAST BY FRIDAY NIGHT AND ALLOW A
FRONTAL SYSTEM TO AFFECT THE STATE NEXT WEEKEND.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR CONDITIONS WILL DOMINATE TODAY AND TONIGHT. HAVE
REMOVED MORNING FOG FROM TAFS WHICH HAD IT IN EITHER PREVAILING OR
TEMPO GROUP (KHUL, KPQI, AND KCAR), AS MID LEVEL CLOUD DECK HAS
KILLED MOST OF THE RADIATION FOG OR PREVENTED ITS FORMATION.
SHORT TERM: VFR EXCEPT IN THUNDERSTORMS. THUNDERSTORMS COULD
AFFECT FVE TUESDAY NIGHT AND OTHER TERMINALS WEDNESDAY AFTERNOON
AND EVENING.
&&
.MARINE...
NEAR TERM: CONDITIONS WILL REMAIN EASILY BELOW SMALL CRAFT LEVELS
THROUGH TONIGHT. EXPECT A SEA BREEZE UP TO 10 KNOTS THIS AFTERNOON.
SHORT TERM: NO SIGNIFICANT WEATHER OUTSIDE OF INCREASING SOUTH
SWELL TOWARDS WEDNESDAY AND THURSDAY. SWELL IS CURRENTLY EXPECTED
REACH JUST OVER 4 FT. WINDS MAY GUST UP TO 20 KTS AHEAD OF A COLD
FRONT LATE WEDNESDAY. THIS FRONT MAY HAVE SOME THUNDERSTORMS
MOVING OVER THE WATER LATE WEDNESDAY AFTERNOON AND WEDNESDAY EVENING.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...FOISY
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...FOISY/MCW
MARINE...FOISY/MCW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
524 AM EDT SUN AUG 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.
TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.
AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 354 AM EDT SUN AUG 24 2014
AFTER A VERY CLOUDY PERIOD OVER THE UPPER GREAT LAKES REGION OVER
THE LAST 7-9 DAYS...EXPECT A TRANSITION TO DRIER...COOLER AND MORE
SUNSHINE FOR THE MIDDLE OF THE WORK WEEK.
THE TRANSITION WILL BE LED BY A COLD FRONT THAT WILL BE MOVING
THROUGH THE CWA MONDAY MORNING AND EARLY AFTERNOON. THIS FRONT IS
ASSOCIATED WITH 1002MB LOW PRESSURE SYSTEM THAT WILL BE MOVING FROM
NEAR LAKE WINNIPEG ON MONDAY MORNING TO JAMES BAY ON MONDAY NIGHT.
AS THIS OCCURS...AN OCCLUDED FRONT WILL STRETCH EAST INTO NORTHERN
ONTARIO AND THEN A COLD FRONT STRETCHING SOUTH ACROSS WEST/CENTRAL
LAKE SUPERIOR AND UPPER MICHIGAN AROUND 12Z ON MONDAY. EXPECT
SHOWERS AND THUNDERSTORMS TO BE ONGOING MONDAY MORNING ALONG THE
FRONT AND SHIFTING EAST THROUGH THE MORNING AND EARLY AFTERNOON
HOURS. CURRENT FORECAST CALLS FOR THE FRONT AND ASSOCIATED
SHOWERS/THUNDERSTORMS TO BE EXITING THE EASTERN CWA TOWARDS THE LATE
AFTERNOON. WHILE THERE IS HIGH CONFIDENCE ON THE TIMING OF THE COLD
FRONT MOVING THROUGH (ALTHOUGH 00Z NAM HAS SLOWED THE FRONT
DOWN A FEW HOURS)...THE AMOUNT OF SHOWERS/THUNDERSTORMS ALONG THE
FRONT IS UNCERTAIN DUE TO SEVERAL LIMITATIONS. THESE LIMITATIONS
INCLUDE THE TIME OF DAY THE FRONT IS MOVING THROUGH...MUCH OF THE
FORCING FROM THE UPPER TROUGH AND SHORTWAVES WELL TO THE NORTHWEST
AND NEAR THE SURFACE LOW...ALONG WITH LIMITED MOISTURE AND WEAK
LAPSE RATES (AROUND 6C/KM) IN THE MID LEVELS. IN ADDITION...A NOSE
OF DRY AIR MOVING IN BETWEEN 900-700MB WILL HELP TO LIMIT ANY
SURFACE OR LOW LEVEL DEVELOPMENT. THESE FACTORS COMBINE TO KEEP POPS
ON THE LOW END OF CHANCES AS THE FRONT MOVES THROUGH AND THINK THE
BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS WILL COME FROM ANY
ONGOING STORMS MOVING INTO THE AREA FROM THE WEST TONIGHT AND TRYING
TO HOLD TOGETHER INTO MONDAY. IF SOMETHING CAN HOLD TOGETHER OR GET
GOING AS THE FRONT MOVES INTO THE EASTERN CWA MONDAY
AFTERNOON...THERE COULD BE STRONG THUNDERSTORMS WITH INSTABILITY ON
THE INCREASE (MU/ML CAPES INCREASING TO 500-1500 J/KG) AND 0-6KM
SHEAR VALUES AROUND 35KTS (OR 25-30KTS OF EFFECTIVE BASED OFF
POTENTIAL FOR ELEVATED THUNDERSTORMS). WEST OF THE COLD FRONT ON
MONDAY...WILL SEE MUCH DRIER AIR MOVING IN AND DEWPOINTS FALLING
INTO THE 50S AND SKIES BECOMING MOSTLY SUNNY.
THE LOW LEVEL WEDGE OF DRY AIR WILL REMAIN INTO MONDAY NIGHT
(PRODUCING PARTLY CLOUDY TO MOSTLY CLEAR SKIES) BEFORE 925-700MB
WINDS TURN MORE TO THE WEST AND EVENTUALLY WEST-NORTHWEST AS A
SECONDARY FRONT/TROUGH MOVES THROUGH. THERE COULD BE SOME SHOWERS
OVER THE SOUTHEAST CWA WITH THIS SECONDARY FRONT AND CLOSER TO
LINGERING MOISTURE FROM THE FIRST FRONT. BEHIND THE SECONDARY
FRONT...MODELS ARE INDICATING AN INCREASE IN 925-850MB MOISTURE
THAT WILL LEAD TO DIURNAL CLOUD DEVELOPMENT DURING THE DAY ON
TUESDAY OVER THE NORTH HALF OF THE LAND CWA EVEN THOUGH A HIGH
PRESSURE RIDGE (FROM A HIGH IN THE EASTERN DAKOTAS) WILL NOSE EAST
OVER THE WESTERN HALF OF THE CWA. FARTHER SOUTH...WOULD EXPECT
MOSTLY SUNNY SKIES AS THE COLD FRONT LOOKS TO SLIDE FAR ENOUGH SOUTH
INTO LOWER MICHIGAN AND SOUTHERN WISCONSIN TO KEEP ANY SHOWERS TO
THE SOUTH OF THE AREA. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES
COOLER ON TUESDAY THAN MONDAY...WITH HIGHS INT HE MID 70S OVER THE
SOUTHEAST HALF AND UPPER 60S OVER THE WEST NEAR LAKE SUPERIOR.
WITH THE FLOW BECOMING ZONAL FOR THE MIDDLE OF THE UPCOMING WORK
WEEK AND THE MAIN SHORTWAVES STAYING NORTH OF THE CWA AND MOVING
ACROSS NORTHERN ONTARIO...EXPECT THE HIGH PRESSURE TO FOLLOW THE
RIDGE EASTWARD WEDNESDAY INTO THURSDAY. THIS WILL PRODUCE DRY
WEATHER AND WITH 850MB TEMPS SLIGHTLY BELOW NORMAL (AROUND
9C) EXPECT HIGHS TO BE SIMILAR WITH RESPECT TO NORMAL. WILL MENTION
THAT THE SOUTH CENTRAL CWA COULD BE BRUSHED BY A FEW WEAK WAVES
RUNNING ALONG THAT FRONT TO THE SOUTH OF THE AREA ON TUESDAY
AND AGAIN THURSDAY...BUT WOULDN/T EXPECT MORE THAN A STRAY SHOWER.
THE HIGH PRESSURE RIDGE WILL BEGIN TO SLIDE EAST ON FRIDAY WHILE AN
UPPER TROUGH SEPARATED FROM THE NORTHERN STREAM FLOW SLIDES EAST
INTO THE CENTRAL PLAINS. THIS WAVE WILL DEVELOP A WEAK SURFACE LOW
IN THE CENTRAL PLAINS AND SLIDE EAST-NORTHEAST THROUGH THE GREAT
LAKES REGION FRIDAY AFTERNOON INTO FRIDAY NIGHT. 00Z GEM
IS CONSISTENT WITH PREVIOUS RUNS AND 00Z ECMWF ON A SLOWER
ARRIVAL WITH THE UPPER TROUGH AND SURFACE LOW...WHILE THE 00Z GFS
LOOKS TO HAVE CONVECTIVE FEEDBACK ISSUES IN THE CENTRAL PLAINS ON
MONDAY/TUESDAY EVENING WHICH SPEEDS UP THE UPPER TROUGH AND
PUSHES IT THROUGH 12-24HRS EARLIER. FEEL A GENERAL CONSENSUS AND
FOCUS TOWARDS THE ECMWF (AND THE MATCHING TIMING WITH THE GEM) IS A
GOOD MIDDLE POINT RIGHT NOW AND WILL FOLLOW THAT IDEA. THIS WAVE
WILL SHIFT EAST OF THE AREA ON SATURDAY AND LEAD TO DRY WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 140 AM EDT SUN AUG 24 2014
A LOT OF HIGH CLOUDS AROUND AND THIS MAY IMPACT IF LOW CLOUDS AND
FOG CAN DEVELOP. GIVEN SE WINDS IN LOW-LEVELS...BEST CHANCE OF LIFR
OR EVEN VLIFR CONDITIONS IS AT KSAW WITH UPSLOPE FLOW LATE IN THE
NIGHT. CHANCES WILL ONLY INCREASE IF HIGH CLOUDS CLEAR OUT MORE THAN
EXPECTED. TRIMMED BACK ON THE CHANCES AT KIWD AND KCMX THOUGH AS THE
LOW-LEVEL WINDS ARE NOT AS FAVORABLE FOR PERSISTENT FOG AT EITHER
SITE...ESPECIALLY AS THICKER HIGHER CLOUDS LIMIT RADIATIONAL FOG
PROCESSES. EXPECT IMPROVEMENT TODAY WITH CIGS LIFTING TO HIGHER MVFR OR
EVEN LOWER VFR AT ALL THE TAF SITES DUE TO DAYTIME MIXING. INVERSION
STUCK AROUND 3KFT WILL LIKELY PROHIBIT CLOUDS FROM CLEARING OUT
COMPELTELY THOUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1204 AM CDT SUN AUG 24 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
STUBBORN LOWER CLOUDS STILL HANGING ON ACROSS NORTHWEST PART OF
THE FORECAST AREA. SULTRY AIRMASS TODAY AS WELL...WITH DEWPOINTS
AROUND 70 SEVERAL LOCATIONS. MOST MODELS TRY TO PUMP IN SOME DRIER
AIR FROM THE SOUTH THROUGH THIS EVENING...WITH THE HRRR MOST
AGGRESSIVE. THAT COULD PROVIDE A LITTLE HUMIDITY RELIEF TO SOME
SPOTS IN THE SOUTHERN/SOUTHEAST FORECAST AREA. AS WE WORK INTO
TONIGHT...THE PROSPECT OF THUNDERSTORMS IS MUCH MUCH LOWER...BUT
NOT NIL. A DECENT LOW LEVEL JET WILL DEVELOP AND THAT COULD SUSTAIN
HIGH PLAINS CONVECTION...BUT ALSO SPARK A FEW OTHER ISOLATED SHOWERS
AND STORMS. OVERALL COVERAGE SHOULD BE ISOLATED...BUT CAN NOT
TOTALLY RULE IT OUT.
SUNDAY SHOULD START WITH LINGERING MID/HIGH CLOUDS FROM LEFTOVER
SHOWERS AND THUNDERSTORMS IN PARTS OF THE PLAINS. THESE MAY HOLD
OVER INTO THE POST SUNRISE HOURS OVER NORTHERN PARTS OF THE
FORECAST NEAR A FRONTAL BOUNDARY...BUT COVERAGE WILL BE SPARSE
AND 20 PERCENT CHANCES REPRESENT RAIN RISK WELL.
A WEAK FRONTAL BOUNDARY WILL ATTEMPT TO MOVE ACROSS THE FORECAST
AREA SUNDAY. MODELS SEEM A BIT AGGRESSIVE...BUT SOMETIMES THAT DOES
WORK OUT. EXPECT A SHIFTING WIND...AND THEN A DYING WIND AS THE
FORECAST IS LEFT TO FLOUNDER IN THE SURFACE SURFACE WITH THE FRONT
WEAKENING WITH TIME. THE WEAK NATURE OF THE FRONT AND SOME WARM MID
LEVEL TEMPERATURES WILL PROBABLY KEEP ANY DEVELOPMENT OF
THUNDERSTORMS NEAR OR ALONG THE FRONT VERY SPARSE AND TOWARD EVENING
AT THE EARLIEST. HAVE KEPT SIMILAR IDEA OF LOWER DEWPOINTS BEHIND
THE FRONTAL PASSAGE...BUT HAVE SOME DOUBT PLACES LIKE GRAND ISLAND
AND HASTINGS COULD DROP TO A SUB-60 DEWPOINT LATE SUNDAY AFTERNOON.
THAT WOULD BE NICE BUT WE WILL SEE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH MUCH OF THE
EXTENDED PERIODS AS THE LOCAL AREA WILL REMAIN UNDER THE INFLUENCE
OF A LARGE TROUGH OF LOW PRESSURE ACROSS THE INTERMOUNTAIN WEST
WITH WEST TO SOUTHWESTERLY FLOW PERSISTING ALOFT.
EXPECT THE MAIN UPPER LEVEL LOW ACROSS THE DAKOTAS SUNDAY EVENING
TO LIFT NORTHEAST...WITH A SECONDARY FRONTAL BOUNDARY PUSHING
ACROSS THE LOCAL AREA. WHILE THIS FRONTAL BOUNDARY MAY PROVIDE THE
TRIGGER FOR SOME ELEVATED CONVECTION ACROSS THE SOUTHEASTERN
PORTIONS OF THE LOCAL AREA EARLY IN THE EVENING...EXPECT THE
BETTER CHANCES TO SPREAD FROM WEST TO EAST AFTER MIDNIGHT AS A
TRAILING MID LEVEL DISTURBANCE MOVES ACROSS THE LOCAL AREA FROM
THE HIGH PLAINS AND A WEAK LOW LEVEL JET FOCUSES ITSELF ACROSS
NORTH CENTRAL KANSAS.
AS THIS FIRST UPPER LEVEL LOW TRACKS WELL INTO CANADA...EXPECT A
SECOND UPPER LEVEL LOW TO SLIDE FROM THE PACIFIC NORTHWEST AND
INTO THE INTERMOUNTAIN WEST BY MONDAY...MAINTAINING SOUTHWESTERLY
ALOFT ACROSS THE REGION. WHILE CHANCES FOR PRECIPITATION WILL
DECREASE SOME DURING THE DAY ON MONDAY...KEPT SOME SMALL POPS IN
THE FORECAST AS THE OLD FRONTAL BOUNDARY WILL BE MEANDERING
ACROSS THE REGION. THAT SAID...THE BETTER SHOT FOR MORE
WIDESPREAD CONVECTION WILL BE MONDAY NIGHT...AS YET ANOTHER UPPER
LEVEL DISTURBANCE IN SOUTHWESTERLY FLOW TRAVERSES THE REGION IN
CONCERT WITH AN INCREASING LOW LEVEL JET AIMED ACROSS SOUTH
CENTRAL NEBRASKA. WITH SEVERAL THOUSAND JOULES OF CAPE IN PLACE
AND MODEST SHEAR VALUES FORECAST...EXPECT THE POTENTIAL FOR AN
ACTIVE NIGHT ACROSS THE LOCAL AREA...ESPECIALLY FROM THE STATE
LINE NORTH. DUE TO SOME DISCREPANCIES IN MODEL DATA...
HOWEVER...ONLY WENT AHEAD AND ADVERTISED LIMITED SEVERE POTENTIAL
FOR MONDAY NIGHT IN THE HWO.
OTHERWISE...THUNDERSTORM ACTIVITY TUESDAY SHOULD ONCE AGAIN BE
FOCUSED NEAR THE LOW LEVEL JET DURING THE EVENING AND OVERNIGHT
HOURS...WITH A COLD FRONT EXPECTED TO BRING YET ANOTHER CHANCE
FOR THUNDERSTORMS ACROSS THE LOCAL AREA WEDNESDAY AND WEDNESDAY
NIGHT. WHILE A CHANCE FOR PRECIPITATION IS IN THE FORECAST SUNDAY
THROUGH THURSDAY...AT THIS TIME THE BEST POTENTIAL FOR ANY SEVERE
WEATHER APPEARS TO BE PRIMARILY DURING THE EVENING AND OVERNIGHT
HOURS MONDAY THROUGH WEDNESDAY...WITH A COOLER...DRIER...AND MORE
STABLE AIRMASS EXPECTED TO SETTLE IN ACROSS THE REGION TO END THE
WEEK.
HYDROLOGY WISE...DUE TO THE RECENT RAINFALL AND SATURATED SOILS
ACROSS MUCH OF THE LOCAL AREA...CONTINUED WITH THE MENTION OF
LOCALIZED FLOODING THE HWO IN THIS UNSETTLED PATTERN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM CDT SAT AUG 23 2014
SCATTERED THUNDERSTORMS DEVELOPED TONIGHT IN WAA AHEAD OF AN
APPROACHING COLD FRONTAL BOUNDARY AND AS THE LLVL JET HAS
STRENGTHENED. IT WILL BE HIT OR MISS ON WHETHER THE CONVECTION
WILL AFFECT THE TERMINALS WITH THE BETTER CHCS NORTH OF KEAR AND
KGRI. THERE WILL BE A PERIOD OF LLVL WIND SHEAR UNTIL THE FRONTAL
BOUNDARY ARRIVES. MAINLY DRY CONDITIONS ARE FORECAST DURING THE
DAYTIME HOURS SUNDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MORITZ
LONG TERM...ROSSI
AVIATION...FAY
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1133 PM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 313 PM CDT SAT AUG 23 2014
H5 ANALYSIS FROM THIS MORNING HAS RIDGING ACROSS THE
MISSISSIPPI VALLEY FROM THE GULF COAST NWD INTO THE WESTERN GREAT
LAKES. FURTHER EAST...DECENT SHORTWAVES WERE NOTED OVER LAKE ONTARIO
AND NOVA SCOTIA. FURTHER WEST...A TANDEM OF SHORTWAVES WERE LOCATED OVER
THE INTERMOUNTAIN WEST. THE FIRST OVER WESTERN COLORADO AND A SECOND
OVER EASTERN IDAHO...WHILE ANOTHER SHORTWAVE WAS UPSTREAM OVER THE
ALASKA PANHANDLE. WV IMAGERY AS OF 1 PM CDT...INDICATED SHORTWAVE
ENERGY IN ASSOCIATION WITH THE WAVE OVER WESTERN COLORADO HAD BEGUN
TO EMERGE ACROSS CENTRAL COLORADO AND HAS LED TO INCREASING
CLOUDINESS ALONG THE FRONT RANGE OF COLORADO. OVER THE NEXT COUPLE
OF HRS...SHRAS AND TSRAS ARE EXPECTED TO DEVELOP ON THE LEE SIDE OF
THE ROCKIES INVOF THE FRONT RANGES OF COLORADO AND WYOMING. FURTHER
WEST...A CLOSED LOW REMAINS IN PLACE OVER EASTERN IDAHO ATTM WITH A
BROAD AREA OF CLOUDS AND SHOWERS ACROSS MONTANA...NORTH DAKOTA AND
NORTHERN SOUTH DAKOTA. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...ABUNDANT CLOUDINESS WAS PRESENT OVER MOST OF THE AREA
WITH THE EXCEPTION OF FAR SWRN NEBRASKA AND THE EASTERN NEBRASKA
PANHANDLE WHERE CLOUDS HAVE SCATTERED OUT OVER THE PAST 1 TO 2
HOURS. AT THE SURFACE...A TANDEM OF LOW PRESSURE CENTERS WERE
PRESENT ACROSS SERN WYOMING AND A SECOND OVER SOUTH CENTRAL SD. A
WARM FRONT EXTENDED FROM SERN WYOMING INTO EASTERN SOUTH
DAKOTA...WHILE A COLD FRONT EXTENDED SSWD INTO THE CENTRAL ROCKIES.
UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES AS OF 3 PM
CDT...RANGED FROM 72 AT AINSWORTH...TO 82 AT BROKEN BOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 313 PM CDT SAT AUG 23 2014
MODELS REMAIN IN GOOD AGREEMENT
WITH THE PROJECTIONS OF A PV ANOMALY LIFTING NORTHEAST FROM FAR
SOUTHWESTERN WYOMING TOWARD THE NORTHERN PLAINS THIS EVENING AND
OVERNIGHT. RECENT OBSERVATIONS INDICATE THAT THE LOW STRATUS IS
DISSIPATING EARLY THIS AFTERNOON...LEADING TO THE EVENTUAL
DESTABILIZATION OF THE LOWER TROPOSPHERE. AS HEIGHTS FALL WITH THE
APPROACH OF THE PV MAX/ATTENDANT COLD FRONT...STORMS ARE ANTICIPATED
TO FORM INVOF OF THE HIGH PLAINS SURFACE LOW/FRONTAL BOUNDARY AND
POSSIBLY DRIFT EAST ACROSS THE SANDHILLS REGION OF NEB OVERNIGHT.
THE LATEST PROJECTIONS FROM THE RAP AND HRRR SHOWS THAT DESPITE THE
MORNING CLOUDS...LOW TO MID LEVEL LAPSE RATES HAVE INCREASED
SOME...YIELDING A WEAKLY UNSTABLE ATMOSPHERE ACROSS WESTERN PORTIONS
OF THE CWA /CONTINUED CLEARING WILL ALLOW FOR FURTHER
DESTABILIZATION/. THE PROJECTED INSTABILITY /UPWARDS TO 1000 J/KG
ML CAPE/ COMBINED WITH 0-6KM BULK SHEAR OF 30KTS OR SO WILL PROMOTE
THE POSSIBILITY OF STRONG TO LOW END SEVERE STORMS THIS EVENING AND
OVERNIGHT. ANOTHER AREA TO WATCH FOR SEVERE STORMS WILL BE ACROSS
NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AS A SECONDARY WARM FRONT
LIFTS NORTH TOWARD THE SOUTHEAST SOUTH DAKOTA. ABUNDANT INSTABILITY
AND SUFFICIENT SHEAR WOULD PROMOTE RAPID STORM DEVELOPMENT CAPABLE
OF LARGE HAIL AND DAMAGING WIND GUSTS.
THE HEAVY RAIN THREAT WILL BE NOTICEABLY LESS TONIGHT AS BUFR
SOUNDINGS REVEAL A MUCH LESSER INFLUENCE FROM WARM RAIN
PROCESSES...BUT WITH PWATS AT OR SLIGHTLY ABOVE AVERAGE...BRIEF
HEAVY RAINFALL IS STILL POSSIBLE.
THE COLD FRONT CLEARS THE CWA EARLY ON SUNDAY WITH RAIN CHANCES
POSSIBLY LINGERING ACROSS OUR FAR EAST THROUGH 15Z...OTHERWISE A
SLIGHTLY COOLER AIRMASS IS ANTICIPATED WITH HIGHS RANGING FROM THE
MID 70S ACROSS OUR FAR NORTHWEST...TO LOW TO MID 80S SOUTH OF THE
INTERSTATE 80 CORRIDOR. WITH MOISTURE LACKING AND A STABLE AIRMASS
ANTICIPATED SUNDAY AFTERNOON...STORM CHANCES SHOULD BE KEPT AT BAY
UNTIL AT LEAST 00Z MONDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CDT SAT AUG 23 2014
SUNDAY NIGHT THROUGH TUESDAY...THE MAIN FORECASTING
CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES AND THE THREAT FOR
HEAVY RAIN AS A TROUGH AND SEMI STATIONARY FRONTAL BOUNDARY PERSISTS
ACROSS THE CENTRAL ROCKIES AND PLAINS DURING THE PERIOD. FOR SUNDAY
NIGHT...AFTER RELATIVELY QUIET WEATHER CONDS SUNDAY...MID LEVEL WAA
WILL INCREASE ALONG THE FRONT RANGE DURING THE
EVENING...TRANSITIONING EAST ACROSS THE CENTRAL PLAINS OVERNIGHT
SUNDAY NIGHT INTO EARLY MONDAY. AT THE SAME TIME...A NICE H250 JET
STREAK WILL LIFT ACROSS NWRN NEBRASKA INTO SOUTH DAKOTA PLACING
WESTERN AND NORTH CENTRAL NEBRASKA IN THE RIGHT REAR QUAD OF THIS
FEATURE. ENHANCED LIFT ACROSS THE FORECAST AREA...WILL LEAD TO A
SHARP INCREASE IN THE THREAT OF PCPN SUNDAY NIGHT INTO MONDAY. IN
THE LOWER LEVELS...A FRONTAL BOUNDARY WILL BE ANCHORED ACROSS SRN
NEBRASKA SUNDAY NIGHT WITH THE NOSE OF A H85 LOW LEVEL JET
POSITIONED ACROSS SWRN NEBRASKA. INHERITED FCST HAD THE HIGHEST POPS
ACROSS SRN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT INTO MONDAY
MORNING AND APPEARS ON TRACK ATTM. PRECIPITATION CHANCES WILL
DECREASE SOMEWHAT MONDAY AS MID LEVEL FORCING PUSHES EAST INTO THE
MID MISSOURI VALLEY. BY MONDAY NIGHT...ANOTHER STRONG UPPER LEVEL
DISTURBANCE WILL PUSH ACROSS THE CENTRAL PLAINS...LEADING TO
INCREASED CHANCES FOR RAIN MONDAY NIGHT...AS WELL AS TUESDAY NIGHT. LOW
LEVEL EASTERLY WINDS AND ABUNDANT MID AND UPPER LEVEL MOISTURE
TRANSPORT FROM THE SOUTHWEST IN ASSOCIATION WITH HURRICANE MARIE
COULD LEAD TO HEAVY RAIN ACROSS THE CENTRAL PLAINS BEGINNING MONDAY
NIGHT AND POSSIBLY PERSISTING INTO TUESDAY NIGHT. FURTHER SUPPORT
FOR HEAVY RAIN IS EVIDENT IN FCST PWATS RANGING FROM 1.5 TO 2.0
INCHES MONDAY NIGHT THROUGH TUESDAY NIGHT.
WEDNESDAY THROUGH SATURDAY...LINGERING PCPN CHANCES ARE THE MAIN
FORECAST CHALLENGE IN THE LONG RANGE PERIODS. BY WEDNESDAY INTO
THURSDAY...THE PERSISTENT UPPER LEVEL TROUGH ACROSS THE
ROCKIES...WILL CROSS THE CENTRAL PLAINS INTO THE MISSISSIPPI VALLEY.
THE LATEST GFS SOLN IS 24 HRS FASTER COMPARED TO THE ECMWF IN
LIFTING THIS FEATURE EAST OF THE AREA. THE GFS IS DRY AFTER WEDS
WITH THE TROUGH OVER MISSOURI VALLEY BY 12Z THURSDAY...WHILE THE
ECMWF HAS THIS FEATURE OVER THE SAME AREA BY 12Z FRIDAY. INHERITED
FCST WAS DRY WEDS NIGHT AND INTRODUCED POPS FOR THIS PERIOD AS BOTH
MODELS HAVE TRENDED SLOWER. WILL HOLD OFF ON INTRODUCING POPS FOR
THURSDAY FOR NOW AND WAIT FOR THE MODELS TO COME INTO BETTER
AGREEMENT. AFTER UNSEASONABLY COOL HIGHS IN THE 70S FOR WEDNESDAY
AND THURSDAY...HIGHS WILL REBOUND BACK INTO THE 80S FOR THURSDAY AND
FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1131 PM CDT SAT AUG 23 2014
TSTM ACTIVITY UNDERWAY SHOULD EXIT THE FCST AREA TO THE EAST 12Z-15Z
SUNDAY MORNING WITH VFR THEREAFTER THROUGH 00Z. THE NEXT AREA OF
TSTMS MAY MOVE INTO SWRN NEB SUNDAY EVENING 03Z-06Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1209 AM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 1209 AM CDT SUN AUG 24 2014
LATEST WATER VAPOR IMAGERY SHOWS AN UPPER LOW CIRCULATING IN
NORTHEAST WYOMING. THE SURFACE LOW WAS REFLECTED OVER BISMARCK
WITH A NORTHWARD MOVEMENT FORECAST AS 3HR MAX PRESSURE FALLS
RESIDED OVER MINOT. WITH THE POSITION OF THE UPPER/SURFACE LOW...A
DRY SLOT IS EVIDENT ON THE WATER VAPOR AND ALSO PER LATEST
LOCAL/REGIONAL RADAR WITH MINIMAL PRECIPITATION OVER THE SOUTHWEST
AND SOUTH CENTRAL. HAVE INCLUDED AREAS OF FOG SOUTHWEST AND PATCHY
FOG ELSEWHERE FOR THE REMAINING PORTION OF THE OVERNIGHT PERIOD.
EXPECT STEADY RAINS CONTINUING IN THE NORTH OVERNIGHT. CURRENT
FORECAST OVERALL IS IN GOOD SHAPE.
UPDATE ISSUED AT 921 PM CDT SAT AUG 23 2014
SEVERAL AREAS OF HEAVY RAIN REMAIN A CONCERN THIS EVENING AND
OVERNIGHT. FIRST...THE FLASH FLOOD WATCH HAS BEEN TRIMMED TO
INCLUDE NOW THE AREAS ALONG AND NORTH OF LAKE SAKAKAWEA AS THE
RAIN SHIELD HAS MOVED NORTH. THIS REPRESENTS FUTURE FLOOD
POTENTIAL TONIGHT AND SUNDAY. TWO AREAS THAT HAVE ALREADY RECEIVED
HEAVY RAIN AND REPORTED OVERLAND FLOODING HAVE FLOOD ADVISORIES
ONGOING. THE FIRST AREA INCLUDES DICKEY AND LAMOURE COUNTIES WHERE
ONGOING TRAINING THUNDERSTORMS LEFT STREET FLOODING IN ELLENDALE.
THE HEAVY RAINFALL SHOULD LAST ANOTHER COUPLE OF HOURS FOLLOWED BY
SLOWLY RECEDING WATER. ANOTHER FLOOD ADVISORY REMAINS IN EFFECT FOR
THE SOUTHWEST WHERE WIDESPREAD 2 INCHES OF RAIN FELL TODAY. WITHIN
THIS AREA AN ENHANCED AREA OF HEAVY RAINFALL...PERHAPS UP TO 4
INCHES...STRETCHES FROM WESTERN SIOUX...CENTRAL GRANT...CENTRAL
MORTON COUNTY NEAR GLEN ULLIN...INTO MERCER COUNTY. WILL KEEP THE
FLOOD ADVISORY GOING FOR THIS AREA AS WELL TONIGHT.
UPDATE ISSUED AT 717 PM CDT SAT AUG 23 2014
FIRST WAVE OF HEAVY RAIN HAS PASSED THROUGH THE SOUTHWEST. SO FAR
WIDESPREAD REPORTS OF AROUND 2 INCHES WITH UPWARDS OF 3 INCHES IN
PLACES. THE RAIN SHIELD IS MOVING INTO THE NORTH CENTRAL FOR THE
REMAINDER OF THE EVENING. SEVERAL LONG LIVED THUNDERSTORMS MOVING
THROUGH NORTHWEST SOUTH DAKOTA SO WILL KEEP FLASH FLOOD WATCH AND
ADVISORIES GOING SOUTHWEST FOR A LITTLE WHILE LONGER. CLUSTER OF
MORE VIGOROUS THUNDERS TOMS MOVING TROUGH SOUTHEAST NORTH DAKOTA.
SEVERE POTENTIAL LIMITED WIND GUSTS TO 40 AND HEAVY RAIN LIKELY
THERE. MID 50S FOR THE HIGH TEMP TODAY NORTHWEST NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE HEAVY
RAIN LATE THIS AFTERNOON AND THIS EVENING. THEN ENDING ACROSS THE
SOUTH LATE THIS EVENING BUT CONTINUING ACROSS THE NORTH INTO
SUNDAY.
LATEST RADAR ESTIMATES HAVE MATCHED UP WELL WITH OBSERVED REPORTS
ACROSS SOUTHWEST NORTH DAKOTA. GENERALLY 1 TO 1.5 INCHES REPORTED
SOUTH AND WEST OF A LINE FROM SELFRIDGE TO THEODORE ROOSEVELT NP.
DID GET A REPORT FROM WFO BILLINGS OF CLOSER TO 5 INCHES NEAR
BAKER MT. AS OF YET CALLS TO SPOTTERS AND BOWMAN EM HAVE RESULTED
IN NO SIGNIFICANT FLOODING ISSUES. HOWEVER...WE HAVE ISSUED AN
AREAL FLOOD ADVISORY SOUTH AND WEST OF LAKE SAKAKAWEA AND THE
MISSOURI RIVER...TO COVER THE 1 TO 1.5 INCHES OF RAIN THAT HAS
FALLEN IN ADDITION TO ADDITIONAL EXPECTED RAIN THROUGH THE
AFTERNOON AND TONIGHT.
REGARDING THE CURRENT FLOOD WATCH AND POTENTIAL OF SEVERE
WEATHER...
WILL LET THE WATCH CONTINUE. HEAVIEST RAIN HAS FALLEN
ACROSS THE MOST SATURATED SOILS IN THE SOUTHWEST. THE HEAVIEST
ADDITIONAL ACCUMULATIONS TONIGHT SHOULD BE CENTERED ACROSS THE
NORTH CENTRAL AND NORTHWEST. IF WE HAD TO PARE IT DOWN...WOULD
PROBABLY REMOVE WELLS SOUTH THROUGH MCINTOSH. HOWEVER...THERE IS
STILL A THREAT OF AFTERNOON AND EVENING CONVECTION HERE AS THE
SURFACE LOW LIFTS INTO NORTH DAKOTA. THUS WILL CONTINUE AS IS FOR
NOW. THE LATEST HRRR STILL DEVELOPS SCATTERED CONVECTION IN THIS
AREA THIS EVENING. HOWEVER THE STRONGEST CONVECTION IS NOW BEING
PLACED TO THE SOUTH OF THE CWA. WITH OUR EAST TO NORTHEAST FLOW AND
COOLER TEMPERATURES OVER NORTH DAKOTA THIS SEEMS REASONABLE...BUT
WITH THE SURFACE LOW LIFTING INTO CENTRAL NORTH DAKOTA THINK OUR
SOUTHEAST CWA WILL BE IN A FAVORED LOCATION FOR ABUNDANT LOW LEVEL
HELICITY THUS WILL CONTINUE A MENTION OF SEVERE OVER THE SOUTHEAST
CWA.
WE DRY OUT FROM SOUTH TO NORTH LATE THIS EVENING THROUGH SUNDAY.
HIGHEST POPS WILL REMAIN OVER THE NORTHWEST AND FAR NORTH CENTRAL.
WITH THE UPPER LEVEL SLOW LIFTING THROUGH EASTERN MONTANA INTO
NORTHWEST ND...THERE SHOULD STILL BE ENOUGH MID TO UPPER LEVEL
FORCING TO MENTION ISOLATED THUNDER THROUGH THE DAY WHEREVER WE
HAVE A MENTION OF SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
SUNDAY EVENING THE UPPER LEVEL LOW IS PROGGED TO BE AT THE BORDER OF
MONTANA AND NORTH DAKOTA...WITH THE SURFACE LOW ALONG THE NORTH
DAKOTA/CANADIAN/MINNESOTA BORDER. THE ELONGATED SURFACE LOW/FRONT
COMBINED WITH THE UPPER LOW TO THE WEST WILL KEEP HIGH CHANCES OF
SHOWERS IN THE NORTHWEST/NORTH CENTRAL SUNDAY NIGHT.
THE SYSTEM LIFTS NORTHEASTWARD SUNDAY NIGHT AND INTO MONDAY...WITH
COLD ADVECTION IN ITS WAKE. LOOKING AT LOWS SUNDAY NIGHT IN THE 40S
WEST TO LOWER 50S IN THE JAMES VALLEY. MOSTLY CLOUDY SKIES NORTH
MONDAY WILL KEEP MAXIMUM TEMPERATURES CONFINED TO THE UPPER 50S WITH
60S SOUTH. BY TUESDAY MORNING THE SURFACE HIGH SETTLES OVER NORTH
DAKOTA...AND LOW TEMPERATURES SHOULD BE IN THE 40S ACROSS WESTERN
AND CENTRAL NORTH DAKOTA.
DURING THE DAY TUESDAY THROUGH WEDNESDAY THE TRAILING UPPER LEVEL
TROUGH MOVES EAST ACROSS THE NORTHERN PLAINS...WITH ISOLATED TO
SCATTERED SHOWERS POSSIBLE. MINOR UPPER LEVEL RIDGING OCCURS
WEDNESDAY NIGHT THROUGH FRIDAY. THE APPROACH OF ANOTHER ROCKIES
TROUGH TOWARDS NEXT WEEKEND MAY BE THE NEXT CHANCE OF SHOWERS AND
THUNDERSTORMS. A SLOW WARMING TREND WITH HIGHS TUESDAY IN THE 60S
WARMING TO THE 80S BY FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1209 AM CDT SUN AUG 24 2014
AREAS OF FOG AND VCSH DOMINATE THE SOUTHERN TERMINALS FOR THE
OVERNIGHT PERIOD AT KDIK/KBIS/KJMS...WHILE STEADY RAINS WILL
CONTINUE AT KISN/KMOT. CIGS WILL REMAIN IN THE LIFR/IFR RANGE
ESPECIALLY NORTH...WITH POCKETS OF MVFR AT KBIS/KJMS. TRENDS SHOW
MAINLY MVFR CIGS DURING THE DAYLIGHT HOURS SUNDAY ACROSS THE
AERODROMES...WITH KJMS IMPROVING TO VFR AFTER 18Z SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 1209 AM CDT SUN AUG 24 2014
A FLOOD WATCH HAS BEEN ISSUED FOR THE KNIFE RIVER NEAR HAZEN AND
FOR SPRING CREEK AT ZAP AS RIVER LEVELS ARE PROJECTED TO RISE INTO
MINOR FLOOD STAGE OVER THE NEXT 24HR PERIOD. WILL CONTINUE TO
MONITOR THE TRENDS THROUGHOUT THE NIGHT AND INTO THE DAY SUNDAY.
MODERATE TO HEAVY RAINS OVER THE PAST WEEK HAVE KEPT SOIL MOISTURE
ABNORMALLY HIGH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. RAINFALL
THAT OCCURRED TODAY...ALONG WITH THE EXPECTED RAINFALL INTO TONIGHT
MAY LIKELY LEAD TO SOME OVERLAND FLOODING...ALONG WITH INCREASED
FLOWS INTO CREEKS...STREAMS...AND RIVERS.
ALONG WITH THE FLOOD WATCH THAT WAS ISSUED ON FRIDAY FOR TODAY
THROUGH SUNDAY...HAVE ALSO ISSUED AN AREAL FLOOD ADVISORY FOR THE
AREA SOUTH AND WEST OF THE MISSOURI RIVER. RADAR ESTIMATES WERE IN
AGREEMENT WITH SOME RAINFALL REPORTS OF 1 TO 1.5 INCHES OF RAINFALL
SO FAR TODAY. IN ADDITION...WHILE THERE IS NO REASONABLE EXPECTATION
OF MAJOR RIVER FLOODING...AT A MINIMUM THERE WILL BE SIGNIFICANT
WITHIN BANK RISES...AND MINOR RIVER FLOODING CANNOT BE RULED OUT.
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
017>023-031>036-040>047-050.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
021>023.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
110 AM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES SUNDAY AND
WEDGE AGAINST THE EASTERN FACE OF THE APPALACHIANS. THIS HIGH
PRESSURE SYSTEM WILL BRING COOLER AND MUCH DRIER AIR TO THE MID
ATLANTIC THROUGH MID WEEK. ANOTHER COLD FRONT WILL APPROACH THE
AREA LATE IN THE WORKWEEK...BRINGING ANOTHER CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1015 PM EDT SATURDAY...
COVERAGE OF SHOWERS ATTM IS LIMITED...AND MAINLY ISOLATED/WIDELY
SCATTERED. BEST COVERAGE REMAINS ALONG EASTERN SLOPES OF THE BLUE
RIDGE FROM BEDFORD SOUTHWEST TO JUST EAST OF WILKESBORO. THE
LATEST HRRR AND THE RUN FROM 22Z ACTUALLY DID A PRETTY GOOD JOB OF
LINING THIS UP THIS EVENING. THE 00Z NAM/12Z ECMWF APPEAR TOO
BULLISH WITH QPF AND MAY BE SUFFERING FROM CONVECTIVE FEEDBACK AS
THEY CONTINUE TO SHOW 3/4 TO 1.5 INCHES ACROSS PORTIONS OF THE
BLUE RIDGE OVERNIGHT. NOT THAT 3/4" COULD NOT OCCUR...BUT OVERALL
CONVECTIVE TRENDS ARE WEAKER...SO NOT REALLY SEEING ANYTHING MORE
THAN A QUICK QUARTER INCH IN A FEW SPOTS.
FORECAST FAVORS THE HRRR AND WILL KEEP HIGHER THREAT OF SHOWERS
ACROSS THE SRN BLUE RIDGE INTO THE OVERNIGHT WITH LESS COVERAGE
FAR SW VA/SE WV AND OVER THE FAR ERN PIEDMONT.
WEDGE ALREADY TAKING SHAPE PER MESOANALYSIS OF SFC LI FIELDS. LOW
IR SAT ALSO SHOWING EXTENSIVE AREA OF LOWER CIGS MOVING IN FROM
THE NE...AS FAR SW AS THE NEW RIVER VALLEY. WILL SEE CLOUDS
OVERSPREAD THE REST OF THE CWA OVERNIGHT THOUGH THE FAR SW VA AREA
MAY SEE LESS CLOUD COVER. TEMPS WILL STAY UP DUE TO THE CLOUDS IN
THE MID 60S TO LOW 70S.
PREVIOUS VALID DISCUSSION...
SHOWER ACTIVITY WILL BE MORE DIMINISHED ON SUNDAY AS HIGH
PRESSURE CONTINUES TO BUILD IN...CAUSING OUR ATMOSPHERE TO DRY
OUT. BEST CHANCES FOR ANY RAINFALL WILL BE EARLY IN THE DAY...WITH
SHOWERS BECOMING INCREASINGLY ISOLATED DURING THE EVENING FROM
SOUTHWEST TO NORTHEAST. WILL ALSO EXPECT DECREASING CLOUD COVER
DURING THE AFTERNOON AND EVENING AS WELL. HIGH PRESSURE SETTLING
IN WILL RESULT IN COOLER AFTERNOON HIGHS...RANGING FROM THE MID
70S ALONG THE RIDGES TO AROUND 80 ACROSS THE SOUTHSIDE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 245 PM EDT SATURDAY...
STRONG WEDGE OF HIGH PRESSURE WILL BE OVER THE FORECAST AREA THROUGH
THE PERIOD.
DEEP ENOUGH LAYER OF NORTHEAST WINDS TO BRING A PUSH OF DRIER AIR
INTO THE FORECAST AREA ABOVE 850 MB SUNDAY NIGHT. HOW FAST THE AIR
MASS BELOW 850 MB DRIES OUT WILL BE CRITICAL TO THE EROSION OF LOW
CLOUDS AND ANY LINGERING DRIZZLE AND FOG. BUFKIT SOUNDING SHOW THE
FAR SOUTHWEST PART OF THE COUNTY WARNING AREA MAY NOT BREAK OUT OF
THE CLOUDS UNTIL AFTER 12Z MONDAY. BY MONDAY NIGHT PRECIPITABLE
WATER VALUES DROP BELOW AN INCH FOR THE ENTIRE FORECAST AREA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 1145 AM EDT SATURDAY...
ANOTHER UPPER TROF WILL LOWER HEIGHTS MORE OVER THE CENTRAL AND
NORTHERN UNITED STATES WEDNESDAY THROUGH SATURDAY WITH THE UPPER
RIDGE CENTERED OFF THE SOUTHEAST COAST.
AT THE SURFACE HIGH PRESSURE WILL BE OVER THE REGION THROUGH
WEDNESDAY. A FRONT WILL EXTEND FROM A LOW OVER THE MID MISSISSIPPI
VALLEY ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES.
SOUTHWARD PROGRESS OF THIS BOUNDARY WILL BE SLOW. ECMWF AND WPC
GUIDANCE KEEP THIS FRONT NORTH OF THE FORECAST AREA THROUGH FRIDAY.
HAVE TRIMMED BACK THE PROBABILITY OF PRECIPITATION THURSDAY AND
FRIDAY WITH THE FORECAST AREA IN THE WARM SECTOR. A BETTER...MORE
ORGANIZED...CHANCE OF PRECIPITATION WILL BE DURING THE WEEKEND WHEN
THE UPPER TROF AND SURFACE COLD FRONT ARRIVE FROM THE WEST.
EXPECTING GRADUALLY MODERATING TEMPERATURES WEDNESDAY AND THURSDAY.
850 MB TEMPERATURES BY 00Z FRIDAY WILL BE BACK UP IN THE +16 TO +20
RANGE. THIS WILL RESULT IN MAXIMUM TEMPERATURES SLIGHTLY ABOVE
NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1250 AM EDT SUNDAY...
BANDS OF SHOWERS CONTINUE TO MEANDER ALONG/EAST OF THE BLUE RIDGE
AND WILL LIKELY PERSIST WHILE SLOWLY FADING AND MOVING SOUTH
THROUGH DAYBREAK. THUS WILL NEED TO KEEP A SHRA MENTION EITHER VIA
PREVAILING OR VCSH AT MOST SPOTS EXCLUDING THE SE WVA LOCATIONS
THROUGH EARLY MORNING.
OTRW STILL LOOKING AT THE WEDGE FRONT TO SLOWLY OOZE SW OVERNIGHT
WITH CIGS SINKING TO MVFR THEN IFR/LIFR INTO EARLY SUNDAY
MORNING. MODEL SOUNDING FORECASTS SUGGEST THAT DRIZZLE APPEARS
LIKELY AT MOST TAF SITES LATE TONIGHT AND WILL BE MAINTAINED AT
MOST EASTERN TAF SPOTS FOR NOW. AT THIS TIME...VSBYS SHOULD STAY
ABOVE 1SM...MORE IN THE 2 TO 6 MILE RANGE WHILE CIGS DROP TO UNDER
1K FT WHICH IS ALREADY ONGOING AT KLYH/KROA. KBLF WHICH WILL BE
THE LAST TO SEE THE BOUNDARY SHIFT THROUGH WILL STAY VFR A WHILE
LONGER BUT THEN ALSO DROP TO MVFR AND IFR BY DAWN SUNDAY.
CIGS WILL BE SLOW TO LIFT SUNDAY MORNING BUT THINK BY LATE
MORNING/MIDDAY WILL SEE MAINLY HIGH END MVFR AT ALL SITES...EXCEPT
VFR AT BLF JUST OUTSIDE THE INFLUENCE OF THE WEDGE.
COULD SEE SOME DRIZZLE OR LIGHT RAIN INTO MIDDAY SUNDAY BUT NOT
ENOUGH COVERAGE TO ADD TO THE TERMINALS AT THIS TIME AS DRIER AIR
ALOFT WILL BE WORKING IN FROM THE NE AS WELL.
ANY SHOWERS WILL BEGIN TO WANE SUNDAY AFTERNOON AS HIGH PRESSURE
CONTINUES TO WEDGE INTO THE REGION...BECOMING THE DOMINANT WEATHER
FEATURE.
THIS HIGH PRESSURE STRETCHING FROM NEW ENGLAND SOUTHWARD ALONG
THE EASTERN FACE OF THE APPALACHIANS WILL MAINTAIN DRY CONDITIONS
THROUGH THE EARLY HALF OF THE WORKWEEK. LONG RANGE MODELS INDICATE
THAT A POTENTIAL TROPICAL CYCLONE DEVELOPING NEAR THE BAHAMAS
SHOULD REMAIN OFF THE EAST COAST AND NOT IMPACT THE LOCAL WEATHER.
A COLD FRONT WILL SINK SOUTHWARD FROM THE GREAT LAKES ON
THURSDAY...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS AS WELL
AS MVFR/IFR CONDITIONS.
&&
.EQUIPMENT...
AS OF 700 PM SATURDAY...
THE ASOS TEMPERATURE AT LYNCHBURG (LYH) VA REMAINS INOP DUE TO A
BOARD FAILURE. TECHNICIANS ARE EXPECTED TO WORK ON THIS MONDAY. TOWER
OBSERVERS ARE AUGMENTING DURING NORMAL SERVICE HOURS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...NF/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...JH/NF/RAB/WP
EQUIPMENT...WP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1005 PM MDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 819 PM MDT SAT AUG 23 2014
LATEST RADAR TRENDS SHOWING THAT SHOWERS AND THUNDERSTORMS HAVE
BEEN DECREASING IN COVERAGE. MOST OF THE CWFA IS PPINE CURRENTLY.
UPPER LOW OVER NORTHWESTERN WYOMING CONTINUES TO MOVE
EAST...GIVING OUR AREA A WESTERLY/DOWNSLOPING WIND COMPONENT. WENT
AHEAD AND LOWERED POPS FOR THE OVERNIGHT HOURS. ONLY AREA THAT MAY
SEE SHOWERS TONIGHT WOULD BE CONVERSE/NIOBRARA ZONES AFTER
MIDNIGHT. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 320 PM MDT SAT AUG 23 2014
CURRENT KCYS RADAR LOOP SHOWS SCATTERED SHOWERS DEVELOPING NEAR
AND EAST OF THE LARAMIE RANGE EARLY THIS AFTERNOON WITH ISOLATED
THUNDERSTORMS EXTENDING EASTWARD INTO WESTERN NEBRASKA. THERE IS A
SMALL CHANCE THAT ONE OR TWO OF THESE TSTORMS MAY BECOME
STRONG WITH HAIL AND GUSTY WINDS...OTHERWISE...MOST OF THE
TSTORM ACTIVITY WILL BE RATHER WEAK WITH MAINLY HEAVY RAINS IN
SOME GUSTY WINDS. A STRONG SURFACE COLD FRONT FOR THIS TIME OF
THE YEAR IS CURRENTLY STALLED ACROSS SOUTHEAST WYOMING...WITH
MAYBE A SLIGHT NUDGE EASTWARD FROM LATE THIS MORNING. 2 PM
TEMPERATURES HAVE LOWERED INTO THE 40S ACROSS CARBON COUNTY...IN
LATE AUGUST...WITH 70S AND AROUND 80 FURTHER TO THE EAST ACROSS
THE HIGH PLAINS OF SOUTHEAST WYOMING. THIS FRONT WILL SLOWLY MOVE
EASTWARD ACROSS THE AREA INTO TONIGHT. OVERNIGHT LOWS WILL BE
CHILLY...WITH READINGS GENERALLY IN THE 40S TO LOW 50S ACROSS THE
EAST PLAINS. SOME OF THE MORE SHELTERED VALLEYS WEST OF THE
LARAMIE RANGE MAY DROP INTO THE MID 30S BY SUNDAY MORNING. DO NOT
EXPECT ANY FOG TONIGHT DUE TO COLD AIR ADVECTION.
SUNDAY WILL LIKELY BE OUR ONLY QUIET DRY DAY IN THE NEAR FUTURE AS
THE UPPER LEVEL LOW LIFTS NORTHEAST OVER EASTERN MONTANA. DRY
WESTERLY FLOW WILL DEVELOP AT ALL LEVELS AS THE NEXT DEEP UPPER
LEVEL TROUGH DIGS SOUTH OUT OF WESTERN CANADA. IT WILL BE ON THE
COOL SIDE AND BREEZY...WITH WEST TO SOUTHWEST WINDS BETWEEN 15 TO
25 MPH AND GUSTS UP TO 40 MPH IN THE AFTERNOON ACROSS SOUTHEAST
WYOMING. HIGH TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S
ACROSS SOUTHEAST WYOMING WITH MOST LOCATIONS NEAR AND WEST OF THE
LARAMIE RANGE IN THE UPPER 60S TO LOW 70S. BY SUNDAY
EVENING...MODELS INDICATE FRONTOGENESIS STARTING TO DEVELOP AS THE
UPPER LEVEL FLOW BECOMES MORE SOUTHERLY. PW/S BELOW ONE HALF INCH
WILL QUICKLY BE REPLACED BY DEWPOINTS CLIMBING INTO THE MID TO
UPPER 40S AND PW/S AROUND 1.00 INCH AS A STATIONARY FRONT DEVELOPS
ACROSS SOUTH CENTRAL WYOMING. THIS WILL RESULT IN SHOWERS AND EVEN
SOME NOCTURNAL THUNDERSTORMS THROUGH MIDNIGHT SUNDAY
NIGHT...MAINLY ACROSS THE SOUTHERN ZONES SOUTH OF THE PLATTE RIVER
VALLEY.
THE UPPER LEVEL TROUGH WILL DIG SOUTH INTO THE GREAT BASIN ON
MONDAY AND THEN GRADUALLY START MOVING EASTWARD LATER IN THE DAY.
WITH DECENT LOW TO MIDLEVEL INSTABILITY...MOISTURE ADVECTION...AND
CAPE OVER 1000 J/KG...EXPECT AFTERNOON SHOWERS AND TSTORMS TO
DEVELOP ACROSS MOST OF THE AREA. DUE TO THE CLOUD COVER...DAYTIME
TEMPERATURES IN THE 70S TO LOW 80 ARE EXPECTED. A FEW OF THE
THUNDERSTORMS MAY BECOME STRONG WITH STRONG GUSTY WINDS AND HAIL
POSSIBLE DUE TO 35 TO 45 KNOTS OF 0-6KM SHEAR.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED 3 PM MDT SAT AUG 23 2014
GFS AND ECMWF MODELS CONTINUE TO HAVE DIFFERING SOLUTIONS WITH
REGARD TO THE NEXT UPPER SYSTEM DROPPING DOWN THE PACIFIC NORTHWEST
INTO OUR AREA MIDWEEK. THE GFS IS MORE OPEN AND PROGRESSIVE WITH
THE UPPER TROUGH TAKING IT EAST OF OUR AREA BY LATE
WEDNESDAY...WHEREAS THE ECMWF IS STILL MUCH SLOWER AND MORE CLOSED
WITH THE UPPER SYSTEM AS IT MOVES SLOWLY EAST ACROSS SOUTHERN
WYOMING ON THURSDAY. BOTH MODELS SHOW A DECENT AMOUNT OF DEEP
LAYERED MOISTURE ON THE EAST SIDE OF THE UPPER TROUGH TUESDAY INTO
WEDNESDAY WHEN WE EXPECT TO SEE SCATTERED SHOWERS AND
THUNDERSTORMS...AND THEN DIVERGE WITH THE GFS DRYING OUT THE
MIDLEVELS QUICKLY ON THURSDAY. FOR NOW WE PUT SOME LOW POPS IN FOR
THE HIGHER ELEVATIONS ON THURSDAY FOR ISOLATED SHOWERS AND
THUNDERSTORMS...AND THAT MAY HAVE TO BE BUMPED UP ACROSS THE
REGION SHOULD THE GFS START TRENDING TOWARDS THE ECMWF. RELATIVELY
COOLER TEMPERATURES EXPECTED EARLY TO MID WEEK AS THE UPPER SYSTEM
MOVES ACROSS...THEN WE SHOULD SEE A BIT OF A WARM-UP BY LATE WEEK
AS RIDGING WORKS IN FROM THE WEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1003 PM MDT SAT AUG 23 2014
LOW PRESSURE TRACKING ACROSS SOUTHERN MONTANA AND NORTHERN WYOMING
WILL GIVE SOUTHEAST WYOMING AND NEBRASKA PANHANDLE A WESTERLY
DOWNSLOPING WIND OVERNIGHT. CHANCES FOR LOW FLIGHT CONDITIONS WITH
THESE WESTERLY WINDS WILL BE QUITE LOW. LATEST HRRR AND SREF
GUIDANCE KEEPS THE AREA VFR THROUGH THE MORNING HOURS.
&&
.FIRE WEATHER...
ISSUED AT 210 PM MDT SAT AUG 23 2014
NO FIRE WEATHER CONCERNS OVER THE NEXT 7 DAYS DUE TO THE UNSETTLED
WEATHER PATTERN OVER THE AREA WELL INTO NEXT WEEK...WITH THE ONLY
DRY DAY BEING ON SUNDAY. MINIMUM RELATIVE HUMIDITIES WILL LOWER
INTO THE 20 TO 35 PERCENT RANGE ALONG WITH EXCELLENT RECOVERIES
OVERNIGHT THROUGH THE MIDDLE OF NEXT WEEK. HIGH TEMPERATURES WILL
GENERALLY RANGE FROM THE LOW 70S TO LOW 80S THROUGH THE PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLAYCOMB
SHORT TERM...TJT
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS MIAMI FL
1050 AM EDT SUN AUG 24 2014
.UPDATE...THE PWAT ON THE MIAMI SOUNDING THIS MORNING WAS
LOWER...1.54 INCHES WITH DRY AIR EVEN IN THE LOWER LEVELS. THIS
WILL LEAD TO LESS CONVECTION THAN TYPICAL. HRRR DELAYS DEVELOPMENT
AND HAS ALL CONVECTION WESTERN INTERIOR-GULF COAST AND NOT UNTIL
AFTER 3 PM AND CONTINUING WELL INTO THE EVENING. GIVEN THE DRIER
AIR, DELAYED DEVELOPMENT LOOKS REASONABLE AND THE WIND PATTERN
DOES SUGGEST A GULF COAST FOCUS...AND ALIGNED POPS AS SUCH WHICH
WAS GENERALLY IN LINE WITH THE INHERITED FORECAST BUT WITH SUBTLE
CHANGES.
TROPICAL STORM CRISTOBAL NEAR THE SE BAHAMAS IS FORECAST TO MOVE
NORTH NORTHWEST THRU WED, THEN TURN NORTHEAST. MODELS HAVE
SOLIDIFIED ON A TRACK EAST OF FLORIDA, SO ASIDE FROM AN INCREASING
RISK OF RIP CURRENTS ALONG THE ATLANTIC BEACHES AND INCREASING
SEAS OVER THE ATLANTIC, NO OTHER IMPACTS ARE EXPECTED BUT WE OF
COURSE WILL CONTINUE TO MONITOR ITS PROGRESS. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 721 AM EDT SUN AUG 24 2014/
AVIATION...
DRIER WEATHER WILL PREVAIL OVER SOUTH FLORIDA TODAY WITH NORTHEAST
WIND FLOW MOST OF THE TAF SITES. THE ONLY EXCEPTION TO THIS IS FOR
KAPF TAF SITE WHERE THE WIND FLOW WILL BECOME WESTERLY AFTER
17Z DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND. SO WILL KEEP
THE WEATHER DRY AT ALL OF THE EAST COAST TAF SITES TODAY AND ONLY
VCSH AT KAPF TAF SITE AFTER 17Z. THE CEILING AND VIS WILL ALSO
REMAIN IN VFR CONDITIONS TODAY.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 246 AM EDT SUN AUG 24 2014/
SHORT TERM (TODAY-TUESDAY)...
A LARGE MID LEVEL RIDGE CURRENTLY CENTERED OVER ARKANSAS WILL SLOWLY
SHIFT TO THE NORTHEAST THROUGH TUESDAY AS A STRONG TROUGH MOVES INTO
THE ATLANTIC OFF THE NEW ENGLAND COAST. THIS WILL MAINTAIN A
NORTHEAST STEERING FLOW ACROSS SOUTH FLORIDA BUT WITH PWAT
CONTINUING TO RUN BELOW THE LATE AUGUST AVERAGE SO ONLY SCATTERED
STORMS CAN BE EXPECTED OVER THE INTERIOR AND SOUTHWEST COAST.
TROPICAL DEPRESSION FOUR IS NOW OVER THE SOUTHEAST BAHAMAS AND THE
LATEST MODEL CONSENSUS IS TO KEEP THE SYSTEM WELL TO THE EAST OF THE
FLORIDA PENINSULA. THE LATEST GFS 00Z RUN ALSO IS MORE IN LINE WITH
THE ECMWF WHICH HAS CONSISTENTLY STEERED TD FOUR THROUGH OR JUST
EAST OF THE BAHAMA ISLAND CHAIN AND THEN NORTH INTO THE OPEN
ATLANTIC. SO DEPENDING ON WHAT STRENGTH THE DISTURBANCE EVENTUALLY
DEVELOPS, THE ONLY IMPACT WILL BE TO CREATE BUILDING SEAS OFF THE
PALM BEACH COAST AS NORTHEAST SWELLS BEGIN TO AFFECT THE COASTAL
WATERS. THE ONLY FLY IN THE OINTMENT WILL BE ON TUESDAY AS THE
TROUGH MOVES OUT OF THE PICTURE AS IT LIFTS TO THE NORTHEAST. THIS
WILL ALLOW THE STEERING FLOW EAST OF THE PENINSULA TO BECOME VERY
WEAK AND THE TROPICAL SYSTEM MAY DRIFT A LITTLE TO THE WEST. SO
RESIDENTS OF SOUTH FLORIDA SHOULD CONTINUE TO MONITOR THE LATEST
FORECASTS FROM NHC.
LONG TERM (WEDNESDAY-SATURDAY)...
THE GFS AND ECMWF ARE IN FAIR AGREEMENT IN THE EXTENDED PERIOD WITH
A SOUTHWEST TO WEST STEERING FLOW DEVELOPING ACROSS SOUTH FLORIDA AS
TD FOUR LIFTS TO THE NORTHEAST. THE MAIN DIFFERENCE IN THEIR
SOLUTIONS IS THAT THE ECMWF KEEPS THE ATMOSPHERE FAIRLY DRY WHILE
THE GFS SHOWS A SIGNIFICANT INCREASE IN TROPICAL MOISTURE. AT ANY
RATE, IT APPEARS THAT THE HIGHEST POPS WILL RETURN TO THE INTERIOR
AND EAST COAST TOWARDS THE END OF THE WEEK AND INTO NEXT WEEKEND.
MARINE...
TROPICAL DEPRESSION FOUR IS FORECAST TO BECOME A TROPICAL STORM
OVER THE SOUTHEASTERN BAHAMAS LATER TODAY. ALTHOUGH CONFIDENCE
REMAINS BELOW NORMAL WITH REGARDS TO POTENTIAL TRACK AND
STRENGTH...THERE IS A CHANCE FOR STRONGER WINDS AND HIGHER SEAS IN
THE MONDAY NIGHT TO WEDNESDAY TIME FRAME IN THE ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 79 90 79 / 10 10 50 20
FORT LAUDERDALE 93 80 92 81 / 10 10 40 30
MIAMI 92 79 90 78 / 10 10 40 30
NAPLES 92 78 94 78 / 30 30 50 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
640 AM EDT SUN AUG 24 2014
.SYNOPSIS...
A WEAK BACK DOOR COLD FRONT ACROSS THE AREA THIS MORNING WILL PUSH
SOUTH OF THE REGION BY THIS AFTERNOON. A FEW SHOWERS ARE POSSIBLE
ALONG AND AHEAD OF THE FRONT. HIGH PRESSURE CENTERED OVER THE
NORTHEASTERN STATES WILL EXTEND INTO THE CAROLINA THROUGH MID WEEK
RESULTING IN FAIR WEATHER WITH NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER LEVEL RIDGE CONTINUES CENTERED OVER THE MISSISSIPPI VALLEY.
UPPER TROUGH OFF THE NEW ENGLAND AND MID ATLANTIC COAST. WEAK
SURFACE COLD FRONT NEAR CAE AT 07Z WILL SLOWLY PUSH SOUTH OF THE
AREA BY THIS AFTERNOON. A FEW SHOWERS CAN BE EXPECTED ALONG AND
AHEAD OF THE FRONT MAINLY THIS MORNING...BUT LACK OF LOW LEVEL
CONVERGENCE...UPPER SUPPORT AND WEAK INSTABILITY WILL LIMIT
COVERAGE. RADAR AT 07Z SHOWING SOME CONVECTION IN THE
PIEDMONT. RAP AND HRRR SUGGEST LOW POPS IN MIDLANDS. STRONGER
CONVERGENCE WILL SHIFT INTO GEORGIA BY THIS AFTERNOON AND EXPECT
DECREASING THREAT OF RAIN BY 18Z. WEAK INSTABILITY SO THUNDER
THREAT LOW. CONSIDERABLE LOW CLOUDS EARLY THIS MORNING WITH BREAKS
DEVELOPING BY MIDDAY THEN DECREASING CLOUDINESS IN THE AFTERNOON
AS DRIER AIR FROM NORTH CAROLINA ADVECTS SOUTH INTO THE REGION.
SHOULD BE COOLER BEHIND FRONT THIS AFTERNOON WITH NORTHEAST
FLOW/WEAK COLD ADVECTION. MOS TEMPERATURES CLOSE AND
ACCEPTED...UPPER 80S AROUND 90.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
HIGH PRESSURE OVER THE NORTHEASTERN STATES WILL BE BUILDING
SOUTHWEST INTO THE CAROLINAS THROUGH THE PERIOD. DRIER AIR
ADVECTING INTO THE REGION THIS EVENING WITH PRECIPITABLE WATER
DECREASING TO LESS THAN 1 INCH BY MONDAY AFTERNOON. DRY CONDITIONS
WITH SEASONABLE TEMPERATURES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA FOR MUCH OF THE WEEK.
ANOTHER COLD FRONT WILL APPROACH THE AREA BY SATURDAY...WITH A
CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY. COOLER
DRY AIR SETTLING IN WILL BRING NEAR NORMAL TEMPS...WITH MAX TEMPS
MAINLY IN THE UPPER 80S TO THE LOWER 90S. OVERNIGHT MINS WILL BE
65 TO 70 RISING INTO THE LOWER 70S LATER IN THE WEEK.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD...WITH MVFR CIGS
POSSIBLE OVER THE NEXT COUPLE OF HOURS.
FRONTAL BOUNDARY ACROSS THE AREA WILL CONTINUE SLOWLY MOVING
SOUTHWARD TODAY AND BE SOUTH OF THE TAF SITES TONIGHT. MVFR CIGS
CURRENTLY OVER CAE/CUB/OGB WILL ALSO BE MOVING SOUTHWARD REACHING
AGS/DNL OVER THE NEXT HOUR OR SO. EXPECT CIGS TO BEGIN IMPROVING
BY MID MORNING WITH ALL SITES RETURNING TO VFR BY 15Z. CONDITIONS
WILL FURTHER IMPROVE THROUGH THIS EVENING AS SLIGHTLY COOLER AND
DRIER AIR BEHIND THE FRONT MOVES INTO THE TAF SITES. WINDS WILL
BE NORTHEASTERLY AROUND 8 KNOTS THROUGH 15Z...INCREASE TO 11
KNOTS WITH GUSTS TO 17 KNOTS BETWEEN 15 AND 23Z...FINALLY
SUBSIDING TO 8 KNOTS FOR THE REMAINDER OF THE PERIOD.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED MONDAY THROUGH THURSDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1024 AM CDT Sun Aug 24 2014
.UPDATE...
ISSUED AT 1024 AM CDT SUN AUG 24 2014
15z/10am surface analysis shows a weak frontal boundary across
central Illinois, generally extending from near Galesburg to just
south of Lawrenceville. Despite presence of boundary, very little
in the way of cloud cover is noted on visible satellite. Most of
the clouds are further north and east across northern Illinois
arcing southeastward into Indiana. Models are showing a mostly dry
forecast today thanks to upper ridging that has sharpened over the
Midwest. NAM is completely dry, but both the HRRR and Rapid Refresh
hint at isolated convection this afternoon across south-central
Illinois. Do not see much support for this at the moment, but will
maintain just slight chance PoPs across the far southeast KILX
CWA. Main story today will be the hot and humid conditions. With
mostly sunny skies, afternoon high temperatures will reach the
lower 90s across the board, with heat index values exceeding 105
degrees along/south of a Lincoln to Marshall line.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT SUN AUG 24 2014
The expected extended period of heat covering a total of four days
has prompted a move to upgrade the heat advisory to a heat warning
in our southern tier of counties. Even if some areas in the warning
do not hit 110F heat index any day, the extended period of
accumulative heat takes the toll as if you are hitting the higher
110F+ readings. Dewpoints climbed well above any guidance numbers
across our S-SE counties Saturday afternoon, with 80 and 81F
dewpoints reported. Guidance showed 75-76F Td for those same areas.
So heat index readings climbed over warning criteria of 110F even on
Saturday, when thoughts were that they would remain around 105F.
Slightly hotter conditions are expected for today and Monday, and if
dewpoints climb to where they were on Saturday, we should reach near
110F heat indices in our S-SE counties. Depending on how the thicker
cirrus clears today, highs should reach into the lower 90s in most
areas, with some mid 90s possible in the south-southwest where the
thermal ridge will begin to build into IL from the SW.
Thunderstorm chances will be more limited today than Saturday,
somewhat due to the increasing mid level temps which help to cap any
updrafts. Due to the orientation and position of the upper level
ridge and residual outflow boundary near our SE counties, we kept
afternoon 20 percent chance PoPs only SE of I-70 for this afternoon
and early evening. The ridge axis up the Mississippi River Valley
should guide that storm track to our N-NW. Very heavy rainfall and
gusty winds will be possible from any storm again today, due to very
high moisture content in the airmass and potential moisture loading
in any storms.
With clearing skies and light wind later tonight, fog will likely
develop into early Monday morning. The restriction to visibility
should not become dense, based on forecast soundings, but local
areas could drop below 1/2 mile near the Indiana border.
&&
.LONG TERM...(Monday through Saturday)
ISSUED AT 251 AM CDT SUN AUG 24 2014
Initial concern with this period continues to be with the heat.
Thermal ridge axis to extend over the CWA through Tuesday, with the
frontal boundary getting hung up to our north. This should result in
high temperatures of 91-95 over the entire forecast area Monday and
Tuesday. Will issue a heat advisory for Monday from around Peoria
southeast to Danville and Paris, as these areas should see heat
index values around 105, and will maintain the advisory around
Rushville and Havana. Will hold off on adding Tuesday at this point,
as there is some question about the amount of clouds and convection
potentially affecting this area.
Regarding that convection, am thinking that Monday and Monday night
should largely be dry, with MCS activity along the front to our
northwest. Most of the evening models show the MCS or its remnants
tracking southeast somewhat on Tuesday, and have PoP`s mentioned
roughly north of I-72. Additional MCS activity likely to form to our
north/northwest Tuesday night as well. The ECMWF/GEM start to sink
the frontal boundary down into our area by this point, while the GFS
has the warm front all the way into southern Wisconsin. Leaned
toward the former solutions and increase the PoP`s from northwest to
southeast Tuesday night into Wednesday.
The forecast beyond Wednesday remains a bit murky. The GFS is
slowing down a bit but remains much more progressive with a broad
trough moving eastward into the Mississippi Valley. The ECMWF and
GEM only slowly break down the ridge and pretty much don`t get the
wave even into the area until mid to late weekend. The tropical
system moving offshore of the East Coast doesn`t help matters
either. Have kept most of the PoP`s focused on the period through
Friday, but confidence in this part of the forecast is lower than
usual.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 657 AM CDT SUN AUG 24 2014
Minor MVFR fog will affect CMI through 14z, otherwise VFR
conditions are expected at the other terminal sites this morning.
Very hot high pressure will keep most cloud cover to a minimum
today, with some scattered 1500-2500FT clouds at times. No rain or
storms are expected near any TAF sites over the next 24 hours, as
mid-level warming advances into IL and pushes the storm tracks
north and east of our area. Forecast soundings show some light
MVFR fog may redevelop near CMI again later tonight, with lower
confidence any other sites will see fog.
Winds this morning will start out east-southeast, then veer to the
south this afternoon. Tonight they are expected to settle into a
southeast direction. Wind speeds should remain less than 10kt due
to a very weak pressure gradient.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.
HEAT ADVISORY from Noon to 7 PM CDT Monday FOR ILZ029-031-037-
038-043>046-055-057.
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ036-040-041.
&&
$$
UPDATE...BARNES
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS PADUCAH KY
626 AM CDT Sun Aug 24 2014
.Update...
Updated aviation section for 12z taf issuance
&&
.SHORT TERM...
Issued at 333 AM CDT Sun Aug 24 2014
There is very little change in the synoptic pattern or the
forecast this forecast cycle. The main issues continue to be the
timing and location of convection...as well as their impacts on
temps/dew points/heat indices.
In the near term...an outflow boundary from last evenings mcs
over the Lower Ohio Valley made it as far southwest as the
Missouri Bootheel by 08z. This mcs and its outflow has stabilized
the air mass for the time being...especially east of the
Mississippi River.
The latest model data /especially the rap/ still indicates the
surface wind flow will become easterly during the day today. The
rap indicates a surface convergence zone along the leading edge of
this easterly push. The RAP model pools moisture along this
boundary...which results in high dew points and an axis of strong
instability by this afternoon. This axis extends from southern
Illinois into western Kentucky by early this afternoon. Based on
this data...will expand slight chance pops as far west as the
Mississippi River counties again today. The coverage of convection
should be rather isolated...given drier mid level air
overspreading the Mississippi Valley on water vapor imagery.
Heat indices will again reach 105 in most areas today. Even where
clouds were widespread on Saturday...heat indices still exceeded
105 due to extremely high dew points around 80. High temps should
be very similar to those on Saturday...except where localized
convection occurs.
The daily potential for isolated convection should be suppressed
further to the south and east Monday and Tuesday as the mid level
ridge axis establishes itself along the Ohio Valley. Will keep
slight chance pops mainly southeast of the Ohio River both days.
As for temps...will generally follow the hotter gfs mos for both
Monday and Tuesday. Some of the model guidance continues to lower
temps slightly. Given that the deep layer ridge will be positioned
nearly overhead through the period...this cooling looks suspect.
There may be a slight lowering of dew points as the low level flow
remains out of the east. This may lower heat indices a few
degrees...but they are still forecast to reach 100 to 105 Tuesday.
.LONG TERM...
Issued at 333 AM CDT Sun Aug 24 2014
Well there continues to be a rift between the GFS and ECMWF/GEM in
their 00Z runs. The trend with all of the models is slower with the
eastward movement of the western U.S. low/trough. The 00Z ECMWF is
leading the charge and tonight`s run basically builds an upper
ridge north of the trough, effectively removing it from the
westerlies. Am beginning to wonder if this system and its associated
surface boundary are ever going to reach our region.
The 00Z GFS brings the upper trough and cold front through the area
Thursday and Thursday night, and then brings drier, cooler air into
the region for Friday and next Saturday. The Canadian/GEM is a lot
closer to the ECMWF solution, but not quite as slow. Really think
the ECMWF is onto something, so will lean toward it for this
forecast.
The problem with the ECMWF and GEM solutions with respect to our
existing forecast is that they allow a significant upper trough to
dive southeast into New England by Thursday morning. That brings a
backdoor cold front southward into our northern counties late
Wednesday and Wednesday night. The front ends up draped across the
area from northwest to southeast Thursday and Friday. This leads to
a decent chance of convection both days.
The other effect of the ECMWF solution is the potential for the heat
and humidity to linger through much of the work week, if not all the
way through next Saturday. Bumped up temperatures just a bit
throughout the extended. Heat indices on Wednesday are generally at
or below 100, so there will be no need to extend the Heat Advisory
any further with this forecast package.
&&
.AVIATION...
Issued at 626 AM CDT Sun Aug 24 2014
Some patchy fog and local areas of low stratus developed before
sunrise in the Wabash Valley and western KY. Most of this fog and
stratus has not reached the taf sites as of 11z. It is expected to
burn off before having a chance to impact the taf sites. There will
likely be more fog and stratus early Monday morning...but it is once
again not expected to be widespread.
Some thunderstorms may develop again today into this evening. The
best chance at this time appears to be in the kpah/kcgi
areas...where the atmosphere was not stabilized too much by
thunderstorms last night. Will handle with vcts for those sites.
Otherwise...scattered to broken cumulus will develop at all sites by
noon. Bases should be around 3 to 4k feet.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...HEAT ADVISORY until 7 PM CDT Tuesday FOR KYZ001>022.
MO...HEAT ADVISORY until 7 PM CDT Tuesday FOR MOZ076-086-087-100-
107>112-114.
IL...HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ075>078-080>094.
IN...HEAT ADVISORY until 7 PM CDT Tuesday FOR INZ081-082-085>088.
&&
$$
SHORT TERM...MY
LONG TERM....DRS
AVIATION...MY
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
958 AM EDT SUN AUG 24 2014
.SYNOPSIS...
A FRONTAL BOUNDARY PUSHES FARTHER SOUTH OF THE AREA TODAY AS HIGH
PRESSURE REMAINS OVER THE NORTHEAST STATES. THE HIGH WILL BUILD
SOUTH INTO THE MID ATLANTIC MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST SFC ANALYSIS REVEALS ~1021 MB HI PRES CENTERED OVR NEW
ENGLAND WITH A FRNTAL BNDRY DROPPING S THRU THE CAROLINAS.
ALOFT...NW FLOW CONTINUES WITH AN UPR-LEVEL RIDGE CENTERED OVR THE
E-CNTRL CONUS. CLOUDS CONTINUE TO SLOWLY MOVE WEST AND MOST
CLOUDINESS IS OVER THE WESTERN MOST COUNTIES. HOWEVER CAN SEE MORE
CU DEVELOPING AND COMING IN OFF THE OCEAN. LOOKING AT THE RAP AND
HRRR BUFKIT SOUNDINGS DOES SHOW MORE PARTLY SUNNY SKIES EAST AND
MADE SOME ADJUSTMENTS TO CLOUD COVER. HELD MAXES ALONG THE COAST
ONLY IN THE MID TO UPPER 70S THIS AFTERNOON. THE WAL SOUNDING
WOULD ONLY SUPPORT A HIGH IN THE MID 70S. WILL BE A LITTLE WARMER
INLAND WITH HIGHS REACHING THE LOW 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SHORT TERM PERIOD WILL BE CHARACTERIZED BY SFC HI PRES LOCKED IN
PLACE ALONG THE NE AND MID ATLANTIC CST...AND UPR-LEVEL RIDGING
ACROSS THE E HALF OF THE CONUS. THIS WILL LEAD TO DRY CONDITIONS
THE ENTIRE PERIOD WITH NE WINDS AND MSTLY SUNNY/CLEAR SKIES. BLO
NORMAL TEMPS WILL CONTINUE...WITH HIGHS MON AND TUE IN THE UPR 70S
TO MID 80S AND LOWS IN THE UPR 50S TO MID 60S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE WX PATTERN THROUGH THE MIDDLE OF NEXT WEEK WILL BE DOMINATED
BY SFC HIGH PRESSURE AND UPPER LEVEL RIDGING ALONG THE EASTERN
SEABOARD. THIS SHOULD KEEP ANY TROPICAL CYCLONE ACTIVITY SHUNTED
WELL SOUTH OF THE REGION THROUGH AT LEAST THURSDAY. THE RIDGING
PATTERN MID-WEEK WILL MAINTAIN A COOL AND DRY AIRMASS OVER THE
AREA THROUGH WED BEFORE THE RIDGE AXES AT THE SFC AND ALOFT ALOFT
BEGIN TO SHIFT EAST OF THE FA...AND MOVING OFFSHORE ON THU. TEMPS
WILL BE SLIGHTLY BELOW NORMAL TUE NIGHT THROUGH WED NIGHT (LOWS IN
THE 60S...UPPER 50S FAR WRN COUNTIES/HIGHS IN THE LOW-MID 80S...
MID-UPPER 70S BEACHES)...THEN SLOWLY MODERATE TWD SEASONAL NORMALS
THU/FRI (HIGHS IN THE MID-UPPER 80S...UPPER 70S-LOWER 80S
BEACHES/LOWS IN THE 60S...AROUND 70 BEACHES). PENDING WX FROM THU
INTO FRI WILL BE HIGHLY DEPENDENT ON TROPICAL ACTIVITY TIMING AND
PLACEMENT. UNCERTAINTY REMAINS HIGH AND PREFER NOT TO LEAN THE
FORECAST HEAVILY TWD ANY GIVEN SOLUTION AT THIS TIME.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
CURRENT TRENDS AND LATEST MODEL DATA IN DECENT AGREEMENT THAT THE
DRYER AIR CONTINUES TO OVERSPREAD THE AREA TODAY WITH ANY BKN SC
DECK SCATTERING OUT AFTER 18Z. FORECAST CONCERN WILL BE THE GUSTY
NE WINDS ALONG THE COAST. DATA SUGGESTS GUSTS BTWN 15-25 KTS ACROSS
THE SERN TAF SITES DURING THE DAYLIGHT HRS. SKC ALONG WITH DININISHING
WINDS AFTER 00Z.
OUTLOOK...DRY WEATHER WITH VFR CONDITIONS EXPECTED FOR NEXT SEVERAL
DAYS AS MID AND LOWER RIDGING TAKES PLACE OVER THE AREA.
&&
.MARINE...
HIGH PRESSURE OVER NEW ENGLAND WILL CONTINUE TO BUILD SOUTH AND OVR
THE WATERS THROUGH MID WEEK. PERSISTANT NE FLOW AND TIGHTENING PRS
GRADIENT WILL KEEP SCA FLAGS FLYING TODAY. WINDS DIMINISH ACROSS THE
CHES BAY BY 00Z. MOUTH OF THE CHES BAY AND CURRITUCK SOUND RATHER
PROBLEMATIC AS WINDS REMAIN IN THE 15-20 KT RANGE ALONG WITH WAVES
AT THE MOUTH HOVERING ARND 4 FT THRU MON. EXTENDED HEADLINES OVER
THE COASTAL WATERS THRU MON NIGHT MAINLY FOR SEAS ARND 5 FT OUT
NEAR 20 NM.
NE FLOW BEGINS TO WANE BY TUESDAY AS HIGH PRESSURE MOVES FARTHER
AWAY FROM THE REGION. HOWEVER...UNCERTAINITY EXISTS IN SEA HEIGHT
FORECAST GIVEN INCREASED SWELL FROM A POTENTIAL TROPICAL SYSTEM
PROGGED TO PASS NEAR THE MID ATLANTIC COAST LATER THIS WEEK.
&&
.TIDES/COASTAL FLOODING...
THREAT NOW OVER FOR PAST HIGH TIDE CYCLE. LEWISETTA CAME IN JUST
BELOW THE MINOR FLOODING LEVEL AS TIDES JUMPED UP TO BETWEEN ONE
TO ONE AND A HALF FEET ABOVE NORMAL. TIDES FOR TODAYS HIGH TIDE
CYCLE PROGGED TO BE AROUND ONE FOOT ABOVE NORMAL...SO LEVELS SHUD
REMAIN BELOW MINOR FLOODING THRESHOLDS. LATEST DATA SUGGESTS ANOTHER
ROUND OF LEVELS FALLING JUST SHORT OF MINOR FLOODING AGAIN TONIGHT.
THUS...ANOTHER ROUND OF STATEMENTS MAY BE NEEDED THIS AFTRN.
MODERATE RIP CURRENT THREAT FOR DELMARVA BEACHES WITH A HIGH RIP
CURRENT RISK FOR VA BEACH / OUTER BANKS CURRITUCK TODAY. SEE CFWAKQ
FOR DETAILS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
MDZ025.
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ102.
VA...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR VAZ098.
MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
VAZ099-100.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR ANZ633-634.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ632.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ630-
631-638.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR ANZ650-652-654-
656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/JAB
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...MPR
MARINE...MPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT SUN AUG 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.
TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.
AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 354 AM EDT SUN AUG 24 2014
AFTER A VERY CLOUDY PERIOD OVER THE UPPER GREAT LAKES REGION OVER
THE LAST 7-9 DAYS...EXPECT A TRANSITION TO DRIER...COOLER AND MORE
SUNSHINE FOR THE MIDDLE OF THE WORK WEEK.
THE TRANSITION WILL BE LED BY A COLD FRONT THAT WILL BE MOVING
THROUGH THE CWA MONDAY MORNING AND EARLY AFTERNOON. THIS FRONT IS
ASSOCIATED WITH 1002MB LOW PRESSURE SYSTEM THAT WILL BE MOVING FROM
NEAR LAKE WINNIPEG ON MONDAY MORNING TO JAMES BAY ON MONDAY NIGHT.
AS THIS OCCURS...AN OCCLUDED FRONT WILL STRETCH EAST INTO NORTHERN
ONTARIO AND THEN A COLD FRONT STRETCHING SOUTH ACROSS WEST/CENTRAL
LAKE SUPERIOR AND UPPER MICHIGAN AROUND 12Z ON MONDAY. EXPECT
SHOWERS AND THUNDERSTORMS TO BE ONGOING MONDAY MORNING ALONG THE
FRONT AND SHIFTING EAST THROUGH THE MORNING AND EARLY AFTERNOON
HOURS. CURRENT FORECAST CALLS FOR THE FRONT AND ASSOCIATED
SHOWERS/THUNDERSTORMS TO BE EXITING THE EASTERN CWA TOWARDS THE LATE
AFTERNOON. WHILE THERE IS HIGH CONFIDENCE ON THE TIMING OF THE COLD
FRONT MOVING THROUGH (ALTHOUGH 00Z NAM HAS SLOWED THE FRONT
DOWN A FEW HOURS)...THE AMOUNT OF SHOWERS/THUNDERSTORMS ALONG THE
FRONT IS UNCERTAIN DUE TO SEVERAL LIMITATIONS. THESE LIMITATIONS
INCLUDE THE TIME OF DAY THE FRONT IS MOVING THROUGH...MUCH OF THE
FORCING FROM THE UPPER TROUGH AND SHORTWAVES WELL TO THE NORTHWEST
AND NEAR THE SURFACE LOW...ALONG WITH LIMITED MOISTURE AND WEAK
LAPSE RATES (AROUND 6C/KM) IN THE MID LEVELS. IN ADDITION...A NOSE
OF DRY AIR MOVING IN BETWEEN 900-700MB WILL HELP TO LIMIT ANY
SURFACE OR LOW LEVEL DEVELOPMENT. THESE FACTORS COMBINE TO KEEP POPS
ON THE LOW END OF CHANCES AS THE FRONT MOVES THROUGH AND THINK THE
BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS WILL COME FROM ANY
ONGOING STORMS MOVING INTO THE AREA FROM THE WEST TONIGHT AND TRYING
TO HOLD TOGETHER INTO MONDAY. IF SOMETHING CAN HOLD TOGETHER OR GET
GOING AS THE FRONT MOVES INTO THE EASTERN CWA MONDAY
AFTERNOON...THERE COULD BE STRONG THUNDERSTORMS WITH INSTABILITY ON
THE INCREASE (MU/ML CAPES INCREASING TO 500-1500 J/KG) AND 0-6KM
SHEAR VALUES AROUND 35KTS (OR 25-30KTS OF EFFECTIVE BASED OFF
POTENTIAL FOR ELEVATED THUNDERSTORMS). WEST OF THE COLD FRONT ON
MONDAY...WILL SEE MUCH DRIER AIR MOVING IN AND DEWPOINTS FALLING
INTO THE 50S AND SKIES BECOMING MOSTLY SUNNY.
THE LOW LEVEL WEDGE OF DRY AIR WILL REMAIN INTO MONDAY NIGHT
(PRODUCING PARTLY CLOUDY TO MOSTLY CLEAR SKIES) BEFORE 925-700MB
WINDS TURN MORE TO THE WEST AND EVENTUALLY WEST-NORTHWEST AS A
SECONDARY FRONT/TROUGH MOVES THROUGH. THERE COULD BE SOME SHOWERS
OVER THE SOUTHEAST CWA WITH THIS SECONDARY FRONT AND CLOSER TO
LINGERING MOISTURE FROM THE FIRST FRONT. BEHIND THE SECONDARY
FRONT...MODELS ARE INDICATING AN INCREASE IN 925-850MB MOISTURE
THAT WILL LEAD TO DIURNAL CLOUD DEVELOPMENT DURING THE DAY ON
TUESDAY OVER THE NORTH HALF OF THE LAND CWA EVEN THOUGH A HIGH
PRESSURE RIDGE (FROM A HIGH IN THE EASTERN DAKOTAS) WILL NOSE EAST
OVER THE WESTERN HALF OF THE CWA. FARTHER SOUTH...WOULD EXPECT
MOSTLY SUNNY SKIES AS THE COLD FRONT LOOKS TO SLIDE FAR ENOUGH SOUTH
INTO LOWER MICHIGAN AND SOUTHERN WISCONSIN TO KEEP ANY SHOWERS TO
THE SOUTH OF THE AREA. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES
COOLER ON TUESDAY THAN MONDAY...WITH HIGHS INT HE MID 70S OVER THE
SOUTHEAST HALF AND UPPER 60S OVER THE WEST NEAR LAKE SUPERIOR.
WITH THE FLOW BECOMING ZONAL FOR THE MIDDLE OF THE UPCOMING WORK
WEEK AND THE MAIN SHORTWAVES STAYING NORTH OF THE CWA AND MOVING
ACROSS NORTHERN ONTARIO...EXPECT THE HIGH PRESSURE TO FOLLOW THE
RIDGE EASTWARD WEDNESDAY INTO THURSDAY. THIS WILL PRODUCE DRY
WEATHER AND WITH 850MB TEMPS SLIGHTLY BELOW NORMAL (AROUND
9C) EXPECT HIGHS TO BE SIMILAR WITH RESPECT TO NORMAL. WILL MENTION
THAT THE SOUTH CENTRAL CWA COULD BE BRUSHED BY A FEW WEAK WAVES
RUNNING ALONG THAT FRONT TO THE SOUTH OF THE AREA ON TUESDAY
AND AGAIN THURSDAY...BUT WOULDN/T EXPECT MORE THAN A STRAY SHOWER.
THE HIGH PRESSURE RIDGE WILL BEGIN TO SLIDE EAST ON FRIDAY WHILE AN
UPPER TROUGH SEPARATED FROM THE NORTHERN STREAM FLOW SLIDES EAST
INTO THE CENTRAL PLAINS. THIS WAVE WILL DEVELOP A WEAK SURFACE LOW
IN THE CENTRAL PLAINS AND SLIDE EAST-NORTHEAST THROUGH THE GREAT
LAKES REGION FRIDAY AFTERNOON INTO FRIDAY NIGHT. 00Z GEM
IS CONSISTENT WITH PREVIOUS RUNS AND 00Z ECMWF ON A SLOWER
ARRIVAL WITH THE UPPER TROUGH AND SURFACE LOW...WHILE THE 00Z GFS
LOOKS TO HAVE CONVECTIVE FEEDBACK ISSUES IN THE CENTRAL PLAINS ON
MONDAY/TUESDAY EVENING WHICH SPEEDS UP THE UPPER TROUGH AND
PUSHES IT THROUGH 12-24HRS EARLIER. FEEL A GENERAL CONSENSUS AND
FOCUS TOWARDS THE ECMWF (AND THE MATCHING TIMING WITH THE GEM) IS A
GOOD MIDDLE POINT RIGHT NOW AND WILL FOLLOW THAT IDEA. THIS WAVE
WILL SHIFT EAST OF THE AREA ON SATURDAY AND LEAD TO DRY WEATHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 738 AM EDT SUN AUG 24 2014
MOIST UPSLOPE FLOW HAS BROUGHT A RETURN OF LIFR CIGS TO KCMX/KSAW.
THESE LOWER CLOUDS SHOULD SCATTER OUT WITH DAYTIME HEATING...
ALLOWING VFR CONDITIONS TO DEVELOP LATE THIS MORNING OR EARLY THIS
AFTN. DOWNSLOPE SE TO S WINDS AT KIWD SHOULD KEEP CONDITIONS VFR
THERE. COLD FRONT APPROACHING FROM THE W SHOULD SPREAD SHRA/TSRA
INTO WRN UPPER MI LATE THIS EVENING. INCLUDED A MENTION OF VCTS AT
KIWD. WITH LESS CONFIDENCE IN TSRA PERSISTING DUE TO DECREASING
INSTABILITY OVERNIGHT...DID NOT INCLUDE A MENTION OF THUNDER AT
KCMX/KSAW. UNDER UPSLOPE WINDS...KSAW SHOULD SEE A RETURN OF MVFR
CIGS TONIGHT...PERHAPS IFR LATE. OTHERWISE...CONDITIONS AT KIWD/KCMX
WILL DEPEND ON INTENSITY OF SHRA THAT OCCUR AT THOSE TERMINALS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
949 AM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 949 AM CDT SUN AUG 24 2014
UPDATED POPS/WX FOR CURRENT RADAR TRENDS. CONVECTION NOW LIMITED
TO THE NORTHERN VALLEY AND A FEW ISOLATED CELLS POPPING UP FURTHER
SOUTH. MUCH OF THE DEVELOPMENT IN THE NEXT FEW HOURS WILL DEPEND
ON CLOUD COVER. THERE IS SOME DECENT CLEARING IN THE SOUTH CENTRAL
CWA...SO THERE COULD BE SOME DESTABILIZATION. RAP AND HRRR HAVE
REDEVELOPMENT MAINLY OVER THE NORTHERN COUNTIES IN THE 20-00Z TIME
FRAME THIS AFTERNOON. WILL CONTINUE TO KEEP SCATTERED POPS GOING
FOR MUCH OF THE DAY...ALTHOUGH SEVERITY IS STILL UNCERTAIN AT THIS
POINT SO WILL LEAVE OUT OF THE GRIDS UNTIL A LATER UPDATE. WILL
KEEP TEMPS ON TRACK TO TOP OUT IN THE 70S TO LOW 80S.
UPDATE ISSUED AT 635 AM CDT SUN AUG 24 2014
RADAR CURRENTLY SHOWING CLUSTER OF THUNDERSTORMS AND HEAVY RAIN
SHOWERS MAINLY NORTH OF HWY 2 CORRIDOR IN THE RED RIVER VALLEY AND
NORTHWEST MINNESOTA...AS WELL AS DOWN THROUGH BELTRAMI COUNTY.
SEEING SOME ISOLATED TSTM ACTIVITY BEHIND MAIN CLUSTER IN EASTERN
ND. HAVE UPDATED POP GRIDS TO REFLECT THIS. NO OTHER CHANGES MADE
THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 357 AM CDT SUN AUG 24 2014
CURRENT RADAR SHOWS A LINE OF THUNDERSTORMS FROM CENTRAL CASS
COUNTY THROUGH CENTRAL OTTER TAIL COUNTY MOVING NORTHWARD INTO WEST
CENTRAL AND NORTHWEST MINNESOTA AS WELL AS CONTINUING ACROSS FAR
EASTERN NORTH DAKOTA...ESPECIALLY BARNES...RANSOM...SARGENT AND
RICHLAND COUNTIES. THOSE FOUR COUNTIES HAVE RECEIVED THE MOST
PRECIPITATION BUT REMAIN BELOW FLASH FLOOD GUIDANCE AND A
HEADLINES FOR WIDESPREAD OVERLAND FLOODING IS NOT EXPECTED HOWEVER
LOCALIZED LOW AREAS COULD SEE STANDING WATER TOMORROW MORNING.
CURRENTLY THE HI RES MODELS HAVE THE BEST HANDLE ON THE
PRECIPITATION AND WILL BE USED THROUGH AROUND 18Z...WHEN THE
PRECIPITATION SHOULD LIFT OUT OF THE REGION AS THE LOW MOVES NORTH
AND A DRY SLOT MOVES INTO MY SOUTHWESTERN ZONES.
TODAY...DRY SLOT WILL MOVE ACROSS THE SOUTHERN VALLEY AND
PRECIPITATION SHOULD BE CONFINED TO MAINLY NORTH OF THE HWY 2
CORRIDOR AND THE FAR EAST. SOME MODELS DO SHOW CU/SHOWERS
DEVELOPING IN THE DRY SLOT BY LATE AFTN AND WILL KEEP SOME LOW
POPS IN MY SOUTHWESTERN ZONES. A SFC BNDRY STRETCHED FROM THE DVL
REGION INTO THE BJI AREA COULD BE THE SOURCE OF STRONG TO POSSIBLY
SEVERE THUNDERSTORMS IN THE NORTHERN VALLEY AND NW MINNESOTA THIS
AFTN...AS HEATING BECOMES MAXIMIZED AND DEEP LAYERED SHEAR
INCREASES TO AROUND 40 KTS BY 21Z. THERE WILL BE ONLY A SMALL
OPPORTUNITY TO HEAT OUT THIS AFTN...SO ATTM CONFIDENCE FOR SVR IS
LOW BUT STILL POSSIBLE. SPC HAS A SLIGHT RISK OUT FOR THIS REGION.
TONIGHT....PRECIP SHOULD BE CONFINED TO ALONG OR NORTH OF THE
INTERNATIONAL BORDER AND SOME LINGERING ISOLATED SHOWERS IN THE
FAR EAST. LOW WILL CONTINUE TO PULL NORTH AND PRECIP SHOULD END BY
MONDAY MORNING. A QUITE COOL AIRMASS WILL THEN WRAP INTO EASTERN
ND AS THE LOW PULLS NORTH...AND OVERNIGHT LOWS COULD DROP INTO THE
40S FOR PARTS OF THE FAR WESTERN CWA.
MONDAY...STRONG COLD ADVECTION INTO THE NORTHERN TIER WILL KEEP
DAYTIME HIGHS WELL BELOW SEASONAL NORMS...WITH THE DEVILS LAKE
BASIN STRUGGLING TO BREAK THE 60 MARK AND MOST OF THE REST OF THE
AREA SEEING DAYTIME HIGHS IN THE MID 60S TO NEAR 70. WINDS WILL BE
WESTERLY AND BREEZY...MAKING A RATHER CHILLY DAY FOR AUGUST. SOME
SHOWERS MAY LINGER ALONG THE INTL BORDER AS THE SFC LOW MOVES INTO
WRN ONTARIO AND HAVE KEPT LOW POPS ACROSS THE EXTREME NORTH.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 357 AM CDT SUN AUG 24 2014
TUESDAY...UNSEASONALLY COOL TEMPERATURES WILL STAY IN PLACE
THROUGH TUESDAY AS SFC HIGH PRESSURE MOVES INTO THE AREA. DAYTIME
HIGHS WILL BE IN THE MID TO UPPER 60S.
BEYOND TUESDAY...LONG WAVE PATTERN FORECAST A ZONAL FLOW ACROSS SOUTHERN
CANADA DURING THIS PERIOD. THE ECMWF IS A FASTER SOLUTION THAN THE
GFS THROUGH THE PERIOD. ECMWF AND GFS HAS BEEN TRENDING SOUTH OVER
THE LAST COUPLE MODEL RUNS. WILL BLEND THE ECMWF AND GFS.
TRIMMED BACK POPS IN FAR SOUTHERN GRANT COUNTY WED AND WED NIGHT.
WILL SHIFT PRECIP EAST ON SAT.
LITTLE CHANGE TO TEMPS...A DEGREE OR SO HIGHER FOR WED AND SAT. NO
CHANGES TO THU OR FRI FROM YESTERDAYS RUN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 635 AM CDT SUN AUG 24 2014
SHRA AND TSTMS NORTH OF GFK AND OVER TVF WILL CONTINUE NORTH THIS
MORNING WITH SOME REDEVELOPING TSRA POSSIBLY MOVING INTO GFK
AREA BY MID MORNING. OVERALL IFR CIGS AT TAF ISSUANCE SHOULD CLIMB
TO MVFR BY MID MORNING...AND HOLD ON THROUGH MUCH OF THE DAY AT
ALL SITES EXCEPT FAR. DO NOT LOOK FOR ANY CLEARING UNTIL AFT
00Z...WHEN WINDS WILL SHIFT SO SW FLOW AND SKIES WILL BEGIN TO
CLEAR. WIND SPEEDS WILL INCREASE THROUGHOUT THE NIGHT AT DVL.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...SPEICHER
LONG TERM...HOPPES/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
132 PM EDT SUN AUG 24 2014
.AVIATION...
THE NORTH TO NORTHEAST WIND FLOW WILL CONTINUE OVER THE EAST COAST
TAF SITES THROUGH REST OF THE AFTERNOON HOURS BEFORE GOING LIGHT
AND VARIABLE TONIGHT. KAPF WINDS WILL REMAIN IN A WESTERLY
DIRECTION AT 5 TO 10 KNOTS BEFORE GOING LIGHT AND VARIABLE FOR
TONIGHT.
THE WEATHER WILL ALSO REMAIN DRY OVER MOST OF SOUTH FLORIDA ALONG
WITH VFR CONDITIONS IN THE CEILING AND VIS THROUGH TONIGHT. THE
ONLY EXCEPTION TO THIS IS THERE COULD BE A SHOWER OR TWO LATE THIS
AFTERNOON OVER KAPF TAF SITE. SO WILL KEEP VCSH IN UNTIL EARLY
THIS EVENING BEFORE GOING DRY FOR TONIGHT.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 1050 AM EDT SUN AUG 24 2014/
UPDATE...THE PWAT ON THE MIAMI SOUNDING THIS MORNING WAS
LOWER...1.54 INCHES WITH DRY AIR EVEN IN THE LOWER LEVELS. THIS
WILL LEAD TO LESS CONVECTION THAN TYPICAL. HRRR DELAYS DEVELOPMENT
AND HAS ALL CONVECTION WESTERN INTERIOR-GULF COAST AND NOT UNTIL
AFTER 3 PM AND CONTINUING WELL INTO THE EVENING. GIVEN THE DRIER
AIR, DELAYED DEVELOPMENT LOOKS REASONABLE AND THE WIND PATTERN
DOES SUGGEST A GULF COAST FOCUS...AND ALIGNED POPS AS SUCH WHICH
WAS GENERALLY IN LINE WITH THE INHERITED FORECAST BUT WITH SUBTLE
CHANGES.
TROPICAL STORM CRISTOBAL NEAR THE SE BAHAMAS IS FORECAST TO MOVE
NORTH NORTHWEST THRU WED, THEN TURN NORTHEAST. MODELS HAVE
SOLIDIFIED ON A TRACK EAST OF FLORIDA, SO ASIDE FROM AN INCREASING
RISK OF RIP CURRENTS ALONG THE ATLANTIC BEACHES AND INCREASING
SEAS OVER THE ATLANTIC, NO OTHER IMPACTS ARE EXPECTED BUT WE OF
COURSE WILL CONTINUE TO MONITOR ITS PROGRESS. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 721 AM EDT SUN AUG 24 2014/
AVIATION...
DRIER WEATHER WILL PREVAIL OVER SOUTH FLORIDA TODAY WITH NORTHEAST
WIND FLOW MOST OF THE TAF SITES. THE ONLY EXCEPTION TO THIS IS FOR
KAPF TAF SITE WHERE THE WIND FLOW WILL BECOME WESTERLY AFTER
17Z DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND. SO WILL KEEP
THE WEATHER DRY AT ALL OF THE EAST COAST TAF SITES TODAY AND ONLY
VCSH AT KAPF TAF SITE AFTER 17Z. THE CEILING AND VIS WILL ALSO
REMAIN IN VFR CONDITIONS TODAY.
&&
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 246 AM EDT SUN AUG 24 2014/
SHORT TERM (TODAY-TUESDAY)...
A LARGE MID LEVEL RIDGE CURRENTLY CENTERED OVER ARKANSAS WILL SLOWLY
SHIFT TO THE NORTHEAST THROUGH TUESDAY AS A STRONG TROUGH MOVES INTO
THE ATLANTIC OFF THE NEW ENGLAND COAST. THIS WILL MAINTAIN A
NORTHEAST STEERING FLOW ACROSS SOUTH FLORIDA BUT WITH PWAT
CONTINUING TO RUN BELOW THE LATE AUGUST AVERAGE SO ONLY SCATTERED
STORMS CAN BE EXPECTED OVER THE INTERIOR AND SOUTHWEST COAST.
TROPICAL DEPRESSION FOUR IS NOW OVER THE SOUTHEAST BAHAMAS AND THE
LATEST MODEL CONSENSUS IS TO KEEP THE SYSTEM WELL TO THE EAST OF THE
FLORIDA PENINSULA. THE LATEST GFS 00Z RUN ALSO IS MORE IN LINE WITH
THE ECMWF WHICH HAS CONSISTENTLY STEERED TD FOUR THROUGH OR JUST
EAST OF THE BAHAMA ISLAND CHAIN AND THEN NORTH INTO THE OPEN
ATLANTIC. SO DEPENDING ON WHAT STRENGTH THE DISTURBANCE EVENTUALLY
DEVELOPS, THE ONLY IMPACT WILL BE TO CREATE BUILDING SEAS OFF THE
PALM BEACH COAST AS NORTHEAST SWELLS BEGIN TO AFFECT THE COASTAL
WATERS. THE ONLY FLY IN THE OINTMENT WILL BE ON TUESDAY AS THE
TROUGH MOVES OUT OF THE PICTURE AS IT LIFTS TO THE NORTHEAST. THIS
WILL ALLOW THE STEERING FLOW EAST OF THE PENINSULA TO BECOME VERY
WEAK AND THE TROPICAL SYSTEM MAY DRIFT A LITTLE TO THE WEST. SO
RESIDENTS OF SOUTH FLORIDA SHOULD CONTINUE TO MONITOR THE LATEST
FORECASTS FROM NHC.
LONG TERM (WEDNESDAY-SATURDAY)...
THE GFS AND ECMWF ARE IN FAIR AGREEMENT IN THE EXTENDED PERIOD WITH
A SOUTHWEST TO WEST STEERING FLOW DEVELOPING ACROSS SOUTH FLORIDA AS
TD FOUR LIFTS TO THE NORTHEAST. THE MAIN DIFFERENCE IN THEIR
SOLUTIONS IS THAT THE ECMWF KEEPS THE ATMOSPHERE FAIRLY DRY WHILE
THE GFS SHOWS A SIGNIFICANT INCREASE IN TROPICAL MOISTURE. AT ANY
RATE, IT APPEARS THAT THE HIGHEST POPS WILL RETURN TO THE INTERIOR
AND EAST COAST TOWARDS THE END OF THE WEEK AND INTO NEXT WEEKEND.
MARINE...
TROPICAL DEPRESSION FOUR IS FORECAST TO BECOME A TROPICAL STORM
OVER THE SOUTHEASTERN BAHAMAS LATER TODAY. ALTHOUGH CONFIDENCE
REMAINS BELOW NORMAL WITH REGARDS TO POTENTIAL TRACK AND
STRENGTH...THERE IS A CHANCE FOR STRONGER WINDS AND HIGHER SEAS IN
THE MONDAY NIGHT TO WEDNESDAY TIME FRAME IN THE ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 79 90 79 / 10 10 50 20
FORT LAUDERDALE 93 80 92 81 / 10 10 40 30
MIAMI 92 79 90 78 / 10 10 40 30
NAPLES 92 78 94 78 / 30 30 50 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...57/DG
LONG TERM....30/KOB
AVIATION...54/BNB
AREA FORECAST DISCUSSION
NWS POCATELLO ID
150 PM MDT SUN AUG 24 2014
.SHORT TERM...TONIGHT THROUGH WEDNESDAY. NEXT UPSTREAM TROUGH
DIGGING SSE THROUGH WRN WASHINGTON/OREGON EARLY THIS AFTERNOON WITH
WEAK TO MODEST AFTERNOON CONVECTION DEVELOPING DOWNSTREAM ACROSS THE
SE IDAHO MOUNTAINS. NUMERICAL MODELS NOT QUITE AS ENTHUSED AS
PREVIOUS RUNS IN DEVELOPING PRECIPITATION ACROSS THE AREA AS UPPER
LOW TAKES SHAPE OVER OREGON LATER THIS EVENING. GFS AND NAM STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE TRACK AND PROGRESSION OF THE
UPPER LOW MONDAY THROUGH WEDNESDAY. THE NAM DRIVES THE LOW INTO NW
NEVADA MONDAY AFTERNOON AND THEN SLOWLY EAST TUESDAY AND WEDNESDAY
WITH ACCOMPANYING PRECIPITATION/CONVECTION SPREADING EAST ACROSS SE
IDAHO. THE GFS ON THE OTHER HAND...SWINGS THE LOW THROUGH SE OREGON
MONDAY AFTERNOON AND THEN EAST ALONG THE NEVADA/UTAH BORDER TUESDAY
AND INTO COLORADO/WYOMING BY NOON WEDNESDAY MUCH FASTER THAN THE
NAM. MAIN DIFFERENCE HERE IS OBVIOUSLY THE ONSET OF DRYING. HAVE
GENERALLY SPLIT THE DIFFERENCE FOR NOW HOLDING ON TO A CHANCE OF
SHOWERS ACROSS THE SE HIGHLANDS TUESDAY NIGHT/WEDNESDAY UNTIL THE
MODELS SHAKE OUT THE DISCONTINUITY.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT SUNDAY. A TRANSIENT RIDGE
WILL SPREAD ACROSS THE AREA WEDNESDAY NIGHT WITH DRY CONDITIONS
PREVAILING THROUGH FRIDAY. THE GFS AND ECMWF CONTINUE TO DIFFER ON
WHETHER SUB-TROPICAL MOISTURE FROM HURRICANE MARIE WILL GET INJECTED
INTO THE NEXT INCOMING TROUGH FOR THE WEEKEND. HAVE MADE NO CHANGES
TO THE CURRENT FORECAST WHICH PROVIDES FOR AT LEAST A CLIMATOLOGICAL
MENTION OF PRECIPITATION...AGAIN UNTIL THE MODELS SHAKE OUT THE
DISCONTINUITY. HUSTON
&&
.AVIATION...ACTIVE WEATHER IS BRIEFLY ON HOLD AS SOUTHEAST IDAHO
SITS BETWEEN THE DEEP UPPER LOW THAT EXITED THE REGION LAST
NIGHT...AND A SECOND UPPER LOW CURRENTLY MAKING ITS WAY INTO THE PAC
NW. MOS GUIDANCE IS DOWNPLAYING CHANCES FOR SHOWERS/THUNDERSTORMS
TODAY. HRRR IS SUGGESTING CONVECTIVE DEVELOPMENT THIS AFTERNOON OVER
THE CENTRAL MOUNTAINS. THIS WILL MAINLY IMPACT KSUN TODAY. STRONGEST
FORCING WILL COME JUST AHEAD OF DEEPENING UPPER LOW BETWEEN 12Z AND
18Z TOMORROW. INCLUDED VCSH AT KSUN AND KBYI. SHOWERS MAY SPREAD
FURTHER INTO SOUTHEAST IDAHO...BUT MODEL CROSS-SECTIONS SUGGEST THIS
WILL OCCUR BEYOND THE TAF PERIOD. TERMINALS EXPECTED TO REMAIN VFR
THROUGH THE PERIOD. HINSBERGER
&&
.FIRE WEATHER...ANOTHER UPPER LOW WILL DROP INTO THE PAC NW TONIGHT
WITH SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED TO SPREAD ACROSS
THE REGION TOMORROW. MODELS ARE TRENDING TOWARDS A SLOWER
PROGRESSION OF THE UPPER LOW...SO SHOWERS MAY LINGER INTO WEDNESDAY
BEFORE RIDGING SPREADS OVER THE AREA. FOCUS OF THE PRECIP WILL BE
PRIMARILY OVER THE MOUNTAINS. WITH RIDGING MOVING INTO THE REGION ON
WEDNESDAY...WE CAN EXPECT WARMER AND DRIER CONDITIONS. ANOTHER
PACIFIC WEATHER SYSTEM WILL MAKE LANDFALL ON FRIDAY. THIS SYSTEM MAY
TAP INTO MOISTURE FROM THE REMNANTS OF HURRICANE MARIE...WHICH WOULD
RESULT IN GREATER RAINFALL AMOUNTS ACROSS THE AREA. HINSBERGER
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
114 PM CDT SUN AUG 24 2014
.DISCUSSION...
330 AM...FORECAST CONCERNS INCLUDE HIGH TEMPS AND HEAT INDICES
TODAY AND MONDAY AND THEN THUNDERSTORMS CHANCES MONDAY MORNING
THROUGH SATURDAY.
IN THE SHORT TERM...A WEAK UPPER WAVE IS VERY SLOWLY MOVING
NORTHEAST ACROSS SOUTHERN LAKE MICHIGAN. SHOWERS AND PERHAPS AN
ISOLATED THUNDERSTORM WILL BE POSSIBLE THROUGH MID MORNING BUT
REMAIN OVER THE LAKE WITH A FEW SPRINKLES OR A SHOWER OVER FAR
NORTHEAST IL THROUGH DAYBREAK.
FOG HAS SO FAR REMAINED PATCHY BUT AS MID/HIGH CLOUDS BEGIN TO
SCATTER FROM WEST TO EAST...FURTHER FOG DEVELOPMENT AND POSSIBLY
SOME DENSE FOG WILL BE POSSIBLE AND WILL ONCE AGAIN NEED TO
MONITOR TRENDS. FOG DEVELOPMENT IS POSSIBLE AGAIN TONIGHT THOUGH
CONFIDENCE REGARDING DENSE FOG IS LOW.
WITH THE UPPER RIDGE BUILDING ACROSS THE AREA TODAY AND TONIGHT...
PRECIP CHANCES APPEAR TO REMAIN BELOW MENTIONABLE POPS. GIVEN THE
VERY MOIST LOW LEVELS...A STRAY THUNDERSTORM CAN/T BE COMPLETELY
RULED OUT BUT HAVE MAINTAINED DRY FORECAST AND WITH THE LACK OF
PRECIP AND CLOUD COVER...THERMAL PROFILES SUGGEST HIGH TEMPS
REACHING THE UPPER 80S TO AROUND 90...COOLER NEAR THE LAKE. WITH
DEWPOINTS REBOUNDING BACK INTO THE LOWER/MID 70S THIS AFTERNOON...
THIS WOULD YIELD HEAT INDICES GENERALLY IN THE UPPER 90S TO AROUND
100. THUS NO HEAT ADVISORY FOR TODAY. IF TEMPERATURES DID WARM A
FEW DEGREES ABOVE EXPECTED VALUES...COULD TAG ADVISORY CRITERIA IN
THE FAR SOUTH.
THERMAL PROFILES WARM A FEW DEGREES ON MONDAY WITH LOW TEMPS
TONIGHT PERHAPS A FEW DEGREES WARMER. WITH ENOUGH SUNSHINE THROUGH
EARLY AFTERNOON...HIGH TEMPERATURES SHOULD REACH LOWER 90S ALL
AREAS...PERHAPS A FEW LOCATIONS TAGGING MID 90S. SOUTHWESTERLY
WINDS NOW APPEARS STRONG ENOUGH TO PREVENT ANY LAKE COOLING...SO
HOT TEMPS ARE EXPECTED TO REACH THE BEACHES/LAKESHORE. DEWPOINTS
REMAIN IN THE LOWER/MID 70S. THIS COMBINATION PRODUCES HEAT
INDICES 100 NORTH TO 106 SOUTH...WHICH WOULD MEET ADVISORY
CRITERIA OVER AT LEAST THE SOUTHERN HALF OR THIRD OF THE CWA.
STILL 3RD PERIOD FROM THIS DISTANCE SO NOT PLANNING ANY HEADLINES
THIS MORNING BUT WILL HIGHLIGHT HEAT/HUMIDITY WITH AN SPS FOR THE
ENTIRE AREA.
A FRONTAL BOUNDARY WILL MOVE ACROSS THE MIDWEST TONIGHT AND MONDAY
AND SAG INTO THE IL/WI STATE LINE REGION MONDAY NIGHT. DISSIPATING
CONVECTION AHEAD OF THIS FRONT COULD POTENTIALLY SAG INTO THE FAR
NORTHERN CWA MONDAY MORNING WITH A LITTLE BETTER CHANCE OF
THUNDERSTORMS MONDAY AFTERNOON...MAINLY ACROSS THE NORTHERN CWA...
AS THE BOUNDARY SLOWLY DRIFTS SOUTH. CONFIDENCE ISN/T HIGH WITH
CONVECTIVE TRENDS DURING THIS TIME AND ITS POSSIBLE THAT THIS
ENTIRE PERIOD COULD REMAIN DRY. SHOULD THUNDERSTORMS BECOME MORE
WIDESPREAD AND/OR OCCUR SOONER...HIGH TEMPERATURES COULD BE TOO
WARM ON MONDAY...PARTICULARLY ACROSS THE NORTH.
THIS FRONTAL BOUNDARY THEN STALLS ACROSS OR NEAR THE AREA THROUGH
MID WEEK. DIFFICULT AT THIS POINT TO NARROW DOWN TIMING OR
LOCATION OF CONVECTION BEYOND MONDAY NIGHT AND THUS CHANCE POPS
FOR THE REMAINDER OF THE PERIOD WITH PERHAPS A SLIGHTLY BETTER
CHANCE FOR OVERNIGHT ACTIVITY TUESDAY NIGHT AND AGAIN WEDNESDAY
NIGHT. DESPITE LOW CONFIDENCE IN TIMING...WHEREVER THUNDERSTORMS
DO DEVELOP...THEY WILL BE EFFICIENT RAIN PRODUCERS AS DEWPOINTS IN
THE 70S ARE RAINED OUT. HEAVY RAIN AND LOCALIZED FLASH FLOODING
WILL BE POSSIBLE AT ANY TIME WITH ANY THUNDERSTORMS THROUGH THE
PERIOD. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTHEAST WINDS BECOMING EAST AT 20-21Z WITH LAKE BREEZE. WIND
SPEEDS AROUND 10 KT.
* MVFR VSBY IN FOG EXPECTED 08-14Z MONDAY.
* SCATTERED THUNDERSTORMS POSSIBLE LATE MONDAY.
ED F
//DISCUSSION...UPDATED 18Z...
WEAK SOUTHEAST FLOW OVER THE AREA THIS AFTERNOON AHEAD OF A COLD
FRONT OVER WESTERN MINNESOTA AND WESTERN IOWA. WEAK GRADIENT WILL
ALLOW LAKE BREEZE TO PUSH INLAND... WHICH IS ALREADY EVIDENT ON
TERMINAL DOPPLER RADARS. EXPECT WINDS TO TURN MORE EAST IN THE
20-21Z HOUR WITH SUSTAINED WINDS AROUND 10 KTS AFTER IT PUSHES THROUGH.
OTHERWISE FAIR WEATHER ALBEIT WARM AND HUMID WITH SCATTERED CU
BASES 025-030 EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.
WINDS EASE OFF TOWARD SUNSET (00-01Z) AND WITH RESIDUAL LOW
LEVEL MOISTURE COMBINED WITH WEAK SOUTHERLY FLOW EXPECT LIGHT FOG
TO DEVELOP OVERNIGHT. MAY SEE LOCALLY DENSE FOG PATCHES WEST OF
THE CHICAGO METRO. HOWEVER WITH A CONTINUED WEAK SOUTHERLY FLOW...
WINDS SHOULD STAY UP JUST ENOUGH TO INHIBIT WIDESPREAD DENSE
FOG... AND URBAN HEAT IMPACTS WILL FURTHER MINIMIZE IMPACT AT ORD
AND MDW.
OUTLOOK FOR MONDAY INCLUDES INCREASING HIGH CLOUDS AHEAD OF RAIN
AND STORMS OFF TO THE WEST WITH SOUTHERLY FLOW INCREASING TO
AROUND 10 KTS DURING THE AFTERNOON. THUNDERSTORM CHANGES INCREASE
FROM THE NORTH AND WEST AHEAD OF THE APPROACHING COLD FRONT THROUGH
THE AFTERNOON AND EVENING.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND DIRECTION CHANGE / LAKE BREEZE
TIMING THIS AFTERNOON. MEDIUM TO HIGH CONFIDENCE IN SPEEDS
AROUND 10 KT AFTER WINDS BECOME EAST.
* MEDIUM CONFIDENCE IN MVFR VSBYS IN FOG EARLY MORNING MONDAY.
* LOW TO MEDIUM CONFIDENCE IN TSTMS LATE MONDAY AFTERNOON.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...PERIODIC CHANCES FOR SHRA/TSRA AND
MVFR.
MDB
&&
.MARINE...
245 AM CDT
LOW PRESSURE CONTINUES TO MOVE NORTHWARD ACROSS THE DAKOTAS WHILE
HIGH PRESSURE OVER SOUTHEASTERN ONTARIO AND SOUTHERN QUEBEC MOVES
SOUTHWARD INTO NEW ENGLAND. A BETTER ORGANIZED PRESSURE GRADIENT
THAN WE HAVE OBSERVED THE PAST FEW DAYS IS IN PLACE ACROSS THE
AREA LEADING TO A BIT STEADIER SOUTHEAST TO EAST WIND ACROSS THE
LAKE TODAY WHICH WILL TURN SOUTHEAST THEN SOUTH TONIGHT AND MONDAY
MORNING. THE LOW WILL TURN EASTWARD ACROSS NORTHERN ONTARIO MONDAY
MORNING AND DRAG A COOL FRONTAL BOUNDARY SOUTHWARD. THE FRONT WILL
BE SLOW TO MOVE DOWN THE LAKE TUESDAY AND WEDNESDAY AND LOOKS TO
STALL OUT SOMEWHERE OVER OR JUST SOUTH OF THE LAKE GOING INTO
WEDNESDAY. AN UPPER TROUGH WILL BE MOVING ONSHORE OVER THE PACIFIC
NORTHWEST SUNDAY NIGHT AND DRIVE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL PLAINS. THIS LOW WILL TRACK NORTHEAST OVER OR NEAR THE
LAKE INTO FRIDAY WITH THE MAIN STORM TRACK SETTING UP ACROSS THE
LAKE THURSDAY AND FRIDAY. WIND SPEEDS FROM EARLY NEXT WEEK ONWARD
WILL BE TRICKY GIVEN THE PRESENCE OF THE FRONT BUT EXPECT
GENERALLY EAST TO NORTHEAST WINDS NORTH OF THE FRONT AND SOUTHERLY
TO THE SOUTH. THERE ARE STILL HINTS THAT COLDER AIR WILL SPILL IN
BEHIND THE FRONT BRINGING A PERIOD OF STRONGER WINDS MID TO LATE
WEEK.
MDB
&&
.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
1247 PM CDT Sun Aug 24 2014
.UPDATE...
ISSUED AT 1024 AM CDT SUN AUG 24 2014
15z/10am surface analysis shows a weak frontal boundary across
central Illinois, generally extending from near Galesburg to just
south of Lawrenceville. Despite presence of boundary, very little
in the way of cloud cover is noted on visible satellite. Most of
the clouds are further north and east across northern Illinois
arcing southeastward into Indiana. Models are showing a mostly dry
forecast today thanks to upper ridging that has sharpened over the
Midwest. NAM is completely dry, but both the HRRR and Rapid Refresh
hint at isolated convection this afternoon across south-central
Illinois. Do not see much support for this at the moment, but will
maintain just slight chance PoPs across the far southeast KILX
CWA. Main story today will be the hot and humid conditions. With
mostly sunny skies, afternoon high temperatures will reach the
lower 90s across the board, with heat index values exceeding 105
degrees along/south of a Lincoln to Marshall line.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT SUN AUG 24 2014
The expected extended period of heat covering a total of four days
has prompted a move to upgrade the heat advisory to a heat warning
in our southern tier of counties. Even if some areas in the warning
do not hit 110F heat index any day, the extended period of
accumulative heat takes the toll as if you are hitting the higher
110F+ readings. Dewpoints climbed well above any guidance numbers
across our S-SE counties Saturday afternoon, with 80 and 81F
dewpoints reported. Guidance showed 75-76F Td for those same areas.
So heat index readings climbed over warning criteria of 110F even on
Saturday, when thoughts were that they would remain around 105F.
Slightly hotter conditions are expected for today and Monday, and if
dewpoints climb to where they were on Saturday, we should reach near
110F heat indices in our S-SE counties. Depending on how the thicker
cirrus clears today, highs should reach into the lower 90s in most
areas, with some mid 90s possible in the south-southwest where the
thermal ridge will begin to build into IL from the SW.
Thunderstorm chances will be more limited today than Saturday,
somewhat due to the increasing mid level temps which help to cap any
updrafts. Due to the orientation and position of the upper level
ridge and residual outflow boundary near our SE counties, we kept
afternoon 20 percent chance PoPs only SE of I-70 for this afternoon
and early evening. The ridge axis up the Mississippi River Valley
should guide that storm track to our N-NW. Very heavy rainfall and
gusty winds will be possible from any storm again today, due to very
high moisture content in the airmass and potential moisture loading
in any storms.
With clearing skies and light wind later tonight, fog will likely
develop into early Monday morning. The restriction to visibility
should not become dense, based on forecast soundings, but local
areas could drop below 1/2 mile near the Indiana border.
&&
.LONG TERM...(Monday through Saturday)
ISSUED AT 251 AM CDT SUN AUG 24 2014
Initial concern with this period continues to be with the heat.
Thermal ridge axis to extend over the CWA through Tuesday, with the
frontal boundary getting hung up to our north. This should result in
high temperatures of 91-95 over the entire forecast area Monday and
Tuesday. Will issue a heat advisory for Monday from around Peoria
southeast to Danville and Paris, as these areas should see heat
index values around 105, and will maintain the advisory around
Rushville and Havana. Will hold off on adding Tuesday at this point,
as there is some question about the amount of clouds and convection
potentially affecting this area.
Regarding that convection, am thinking that Monday and Monday night
should largely be dry, with MCS activity along the front to our
northwest. Most of the evening models show the MCS or its remnants
tracking southeast somewhat on Tuesday, and have PoP`s mentioned
roughly north of I-72. Additional MCS activity likely to form to our
north/northwest Tuesday night as well. The ECMWF/GEM start to sink
the frontal boundary down into our area by this point, while the GFS
has the warm front all the way into southern Wisconsin. Leaned
toward the former solutions and increase the PoP`s from northwest to
southeast Tuesday night into Wednesday.
The forecast beyond Wednesday remains a bit murky. The GFS is
slowing down a bit but remains much more progressive with a broad
trough moving eastward into the Mississippi Valley. The ECMWF and
GEM only slowly break down the ridge and pretty much don`t get the
wave even into the area until mid to late weekend. The tropical
system moving offshore of the East Coast doesn`t help matters
either. Have kept most of the PoP`s focused on the period through
Friday, but confidence in this part of the forecast is lower than
usual.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1247 PM CDT SUN AUG 24 2014
Thanks to strong upper ridge axis in place across the region,
mostly sunny skies will prevail across central Illinois this
afternoon. Latest visible satellite imagery is showing SCT-BKN Cu
developing along/east of the I-57 corridor. Based on satellite
trends and Cu-rule, have included SCT clouds at around 2500ft at
both KBMI and KCMI accordingly. Main aviation question is whether
or not fog will develop tonight. Very little fog was observed last
night: however, airmass will remain quite moist and low-level winds
will be light from the S/SE overnight. Forecast soundings and
numeric guidance suggest at least patchy fog will form late
tonight, so have included a minimal reduction in visby at all
terminals between 09z and 13z. Introduced the lowest visbys down
to 3sm at both KBMI and KCMI where fog occurred last night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.
HEAT ADVISORY from Noon to 7 PM CDT Monday FOR ILZ029-031-037-
038-043>046-055-057.
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ036-040-041.
&&
$$
UPDATE...BARNES
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1117 AM CDT SUN AUG 24 2014
.DISCUSSION...
330 AM...FORECAST CONCERNS INCLUDE HIGH TEMPS AND HEAT INDICES
TODAY AND MONDAY AND THEN THUNDERSTORMS CHANCES MONDAY MORNING
THROUGH SATURDAY.
IN THE SHORT TERM...A WEAK UPPER WAVE IS VERY SLOWLY MOVING
NORTHEAST ACROSS SOUTHERN LAKE MICHIGAN. SHOWERS AND PERHAPS AN
ISOLATED THUNDERSTORM WILL BE POSSIBLE THROUGH MID MORNING BUT
REMAIN OVER THE LAKE WITH A FEW SPRINKLES OR A SHOWER OVER FAR
NORTHEAST IL THROUGH DAYBREAK.
FOG HAS SO FAR REMAINED PATCHY BUT AS MID/HIGH CLOUDS BEGIN TO
SCATTER FROM WEST TO EAST...FURTHER FOG DEVELOPMENT AND POSSIBLY
SOME DENSE FOG WILL BE POSSIBLE AND WILL ONCE AGAIN NEED TO
MONITOR TRENDS. FOG DEVELOPMENT IS POSSIBLE AGAIN TONIGHT THOUGH
CONFIDENCE REGARDING DENSE FOG IS LOW.
WITH THE UPPER RIDGE BUILDING ACROSS THE AREA TODAY AND TONIGHT...
PRECIP CHANCES APPEAR TO REMAIN BELOW MENTIONABLE POPS. GIVEN THE
VERY MOIST LOW LEVELS...A STRAY THUNDERSTORM CAN/T BE COMPLETELY
RULED OUT BUT HAVE MAINTAINED DRY FORECAST AND WITH THE LACK OF
PRECIP AND CLOUD COVER...THERMAL PROFILES SUGGEST HIGH TEMPS
REACHING THE UPPER 80S TO AROUND 90...COOLER NEAR THE LAKE. WITH
DEWPOINTS REBOUNDING BACK INTO THE LOWER/MID 70S THIS AFTERNOON...
THIS WOULD YIELD HEAT INDICES GENERALLY IN THE UPPER 90S TO AROUND
100. THUS NO HEAT ADVISORY FOR TODAY. IF TEMPERATURES DID WARM A
FEW DEGREES ABOVE EXPECTED VALUES...COULD TAG ADVISORY CRITERIA IN
THE FAR SOUTH.
THERMAL PROFILES WARM A FEW DEGREES ON MONDAY WITH LOW TEMPS
TONIGHT PERHAPS A FEW DEGREES WARMER. WITH ENOUGH SUNSHINE THROUGH
EARLY AFTERNOON...HIGH TEMPERATURES SHOULD REACH LOWER 90S ALL
AREAS...PERHAPS A FEW LOCATIONS TAGGING MID 90S. SOUTHWESTERLY
WINDS NOW APPEARS STRONG ENOUGH TO PREVENT ANY LAKE COOLING...SO
HOT TEMPS ARE EXPECTED TO REACH THE BEACHES/LAKESHORE. DEWPOINTS
REMAIN IN THE LOWER/MID 70S. THIS COMBINATION PRODUCES HEAT
INDICES 100 NORTH TO 106 SOUTH...WHICH WOULD MEET ADVISORY
CRITERIA OVER AT LEAST THE SOUTHERN HALF OR THIRD OF THE CWA.
STILL 3RD PERIOD FROM THIS DISTANCE SO NOT PLANNING ANY HEADLINES
THIS MORNING BUT WILL HIGHLIGHT HEAT/HUMIDITY WITH AN SPS FOR THE
ENTIRE AREA.
A FRONTAL BOUNDARY WILL MOVE ACROSS THE MIDWEST TONIGHT AND MONDAY
AND SAG INTO THE IL/WI STATE LINE REGION MONDAY NIGHT. DISSIPATING
CONVECTION AHEAD OF THIS FRONT COULD POTENTIALLY SAG INTO THE FAR
NORTHERN CWA MONDAY MORNING WITH A LITTLE BETTER CHANCE OF
THUNDERSTORMS MONDAY AFTERNOON...MAINLY ACROSS THE NORTHERN CWA...
AS THE BOUNDARY SLOWLY DRIFTS SOUTH. CONFIDENCE ISN/T HIGH WITH
CONVECTIVE TRENDS DURING THIS TIME AND ITS POSSIBLE THAT THIS
ENTIRE PERIOD COULD REMAIN DRY. SHOULD THUNDERSTORMS BECOME MORE
WIDESPREAD AND/OR OCCUR SOONER...HIGH TEMPERATURES COULD BE TOO
WARM ON MONDAY...PARTICULARLY ACROSS THE NORTH.
THIS FRONTAL BOUNDARY THEN STALLS ACROSS OR NEAR THE AREA THROUGH
MID WEEK. DIFFICULT AT THIS POINT TO NARROW DOWN TIMING OR
LOCATION OF CONVECTION BEYOND MONDAY NIGHT AND THUS CHANCE POPS
FOR THE REMAINDER OF THE PERIOD WITH PERHAPS A SLIGHTLY BETTER
CHANCE FOR OVERNIGHT ACTIVITY TUESDAY NIGHT AND AGAIN WEDNESDAY
NIGHT. DESPITE LOW CONFIDENCE IN TIMING...WHEREVER THUNDERSTORMS
DO DEVELOP...THEY WILL BE EFFICIENT RAIN PRODUCERS AS DEWPOINTS IN
THE 70S ARE RAINED OUT. HEAVY RAIN AND LOCALIZED FLASH FLOODING
WILL BE POSSIBLE AT ANY TIME WITH ANY THUNDERSTORMS THROUGH THE
PERIOD. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* ADDITIONAL BRIEF MVFR CIG POSSIBLE AGAIN EARLY AFTERNOON.
* SOUTHEAST WINDS BECOMING EAST MID AFTERNOON. SPEEDS AROUND 10 KT.
* MVFR VSBY IN FOG POSSIBLE DAYBREAK MONDAY.
ED F
//DISCUSSION...UPDATED 12Z...
MVFR CIGS PERSIST THIS MORNING WITH MORE VARIABILITY ALONG THE
WESTERN FLANK OF THE CLOUD BAND FROM RFD TO JOT. EARLIER CIRRUS IS
ERODING ABOVE WHICH SHOULD ALLOW SUNSHINE TO HELP SCATTER THE
CLOUDS INTO THE MID MORNING HOURS. WITH HEATING AND START OF
MIXING NEW STRATOCU IS EXPECTED TO DEVELOP MID TO LATE MORNING.
THIS COULD BE OCCASIONALLY BROKEN IN COVERAGE BUT EXPECT SCATTERED
SKIES FOR THE BULK OF THE AFTERNOON. WILL NEED TO MONITOR A PATCH
OF IFR CIGS FROM NORTH OF VYS TO C75 TO PNT. THIS COULD BE A
CONCERN FOR RFD AS IT MAY SPREAD NORTHWARD TO SOME DEGREE.
SOUTHEAST WINDS WILL INCREASE TO AROUND 10 KT WITH SOME 10-12 KT
OBS ALREADY REPORTED THIS MORNING. A LAKE BREEZE IS EXPECTED TO
WORK INLAND AND TURN WINDS MORE EASTERLY AT ORD/MDW AND
NORTHEASTERLY AT GYY. EXPECT SPEEDS AROUND 10 KT WITH THE LAKE
BREEZE PASSAGE THOUGH THEY COULD BE A LITTLE BIT STRONGER FOR A
SHORT TIME. CANNOT RULE OUT A STRAY THUNDERSTORM THIS AFTERNOON AS
A WEAK UPPER DISTURBANCE CROSSES THE AREA MID/LATE AFTERNOON.
WINDS DO NOT LOOK TO COMPLETELY DROP OFF TONIGHT WHICH MAY HELP
LIMIT FOG/STRATUS DEVELOPMENT BUT MVFR VSBY DOES LOOK POSSIBLE.
WILL INCLUDE MENTION AT RFD/DPA WHICH ARE MORE PRONE TO VSBY
REDUCTION.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW TO MEDIUM CONFIDENCE IN ADDITIONAL BRIEF PERIOD OF MVFR CIGS EARLY
AFTERNOON.
* HIGH CONFIDENCE IN SOUTHEAST WINDS WITH MEDIUM CONFIDENCE IN SHIFT
TO EAST THIS AFTERNOON. MEDIUM-HIGH CONFIDENCE IN SPEEDS AROUND
10 KT.
* LOW TO MEDIUM CONFIDENCE IN MVFR VSBY IN FOG MONDAY MORNING.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...PERIODIC CHANCES FOR SHRA/TSRA AND
MVFR.
MDB
&&
.MARINE...
245 AM CDT
LOW PRESSURE CONTINUES TO MOVE NORTHWARD ACROSS THE DAKOTAS WHILE
HIGH PRESSURE OVER SOUTHEASTERN ONTARIO AND SOUTHERN QUEBEC MOVES
SOUTHWARD INTO NEW ENGLAND. A BETTER ORGANIZED PRESSURE GRADIENT
THAN WE HAVE OBSERVED THE PAST FEW DAYS IS IN PLACE ACROSS THE
AREA LEADING TO A BIT STEADIER SOUTHEAST TO EAST WIND ACROSS THE
LAKE TODAY WHICH WILL TURN SOUTHEAST THEN SOUTH TONIGHT AND MONDAY
MORNING. THE LOW WILL TURN EASTWARD ACROSS NORTHERN ONTARIO MONDAY
MORNING AND DRAG A COOL FRONTAL BOUNDARY SOUTHWARD. THE FRONT WILL
BE SLOW TO MOVE DOWN THE LAKE TUESDAY AND WEDNESDAY AND LOOKS TO
STALL OUT SOMEWHERE OVER OR JUST SOUTH OF THE LAKE GOING INTO
WEDNESDAY. AN UPPER TROUGH WILL BE MOVING ONSHORE OVER THE PACIFIC
NORTHWEST SUNDAY NIGHT AND DRIVE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL PLAINS. THIS LOW WILL TRACK NORTHEAST OVER OR NEAR THE
LAKE INTO FRIDAY WITH THE MAIN STORM TRACK SETTING UP ACROSS THE
LAKE THURSDAY AND FRIDAY. WIND SPEEDS FROM EARLY NEXT WEEK ONWARD
WILL BE TRICKY GIVEN THE PRESENCE OF THE FRONT BUT EXPECT
GENERALLY EAST TO NORTHEAST WINDS NORTH OF THE FRONT AND SOUTHERLY
TO THE SOUTH. THERE ARE STILL HINTS THAT COLDER AIR WILL SPILL IN
BEHIND THE FRONT BRINGING A PERIOD OF STRONGER WINDS MID TO LATE
WEEK.
MDB
&&
.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
1024 AM CDT Sun Aug 24 2014
.UPDATE...
ISSUED AT 1024 AM CDT SUN AUG 24 2014
15z/10am surface analysis shows a weak frontal boundary across
central Illinois, generally extending from near Galesburg to just
south of Lawrenceville. Despite presence of boundary, very little
in the way of cloud cover is noted on visible satellite. Most of
the clouds are further north and east across northern Illinois
arcing southeastward into Indiana. Models are showing a mostly dry
forecast today thanks to upper ridging that has sharpened over the
Midwest. NAM is completely dry, but both the HRRR and Rapid Refresh
hint at isolated convection this afternoon across south-central
Illinois. Do not see much support for this at the moment, but will
maintain just slight chance PoPs across the far southeast KILX
CWA. Main story today will be the hot and humid conditions. With
mostly sunny skies, afternoon high temperatures will reach the
lower 90s across the board, with heat index values exceeding 105
degrees along/south of a Lincoln to Marshall line.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT SUN AUG 24 2014
The expected extended period of heat covering a total of four days
has prompted a move to upgrade the heat advisory to a heat warning
in our southern tier of counties. Even if some areas in the warning
do not hit 110F heat index any day, the extended period of
accumulative heat takes the toll as if you are hitting the higher
110F+ readings. Dewpoints climbed well above any guidance numbers
across our S-SE counties Saturday afternoon, with 80 and 81F
dewpoints reported. Guidance showed 75-76F Td for those same areas.
So heat index readings climbed over warning criteria of 110F even on
Saturday, when thoughts were that they would remain around 105F.
Slightly hotter conditions are expected for today and Monday, and if
dewpoints climb to where they were on Saturday, we should reach near
110F heat indices in our S-SE counties. Depending on how the thicker
cirrus clears today, highs should reach into the lower 90s in most
areas, with some mid 90s possible in the south-southwest where the
thermal ridge will begin to build into IL from the SW.
Thunderstorm chances will be more limited today than Saturday,
somewhat due to the increasing mid level temps which help to cap any
updrafts. Due to the orientation and position of the upper level
ridge and residual outflow boundary near our SE counties, we kept
afternoon 20 percent chance PoPs only SE of I-70 for this afternoon
and early evening. The ridge axis up the Mississippi River Valley
should guide that storm track to our N-NW. Very heavy rainfall and
gusty winds will be possible from any storm again today, due to very
high moisture content in the airmass and potential moisture loading
in any storms.
With clearing skies and light wind later tonight, fog will likely
develop into early Monday morning. The restriction to visibility
should not become dense, based on forecast soundings, but local
areas could drop below 1/2 mile near the Indiana border.
&&
.LONG TERM...(Monday through Saturday)
ISSUED AT 251 AM CDT SUN AUG 24 2014
Initial concern with this period continues to be with the heat.
Thermal ridge axis to extend over the CWA through Tuesday, with the
frontal boundary getting hung up to our north. This should result in
high temperatures of 91-95 over the entire forecast area Monday and
Tuesday. Will issue a heat advisory for Monday from around Peoria
southeast to Danville and Paris, as these areas should see heat
index values around 105, and will maintain the advisory around
Rushville and Havana. Will hold off on adding Tuesday at this point,
as there is some question about the amount of clouds and convection
potentially affecting this area.
Regarding that convection, am thinking that Monday and Monday night
should largely be dry, with MCS activity along the front to our
northwest. Most of the evening models show the MCS or its remnants
tracking southeast somewhat on Tuesday, and have PoP`s mentioned
roughly north of I-72. Additional MCS activity likely to form to our
north/northwest Tuesday night as well. The ECMWF/GEM start to sink
the frontal boundary down into our area by this point, while the GFS
has the warm front all the way into southern Wisconsin. Leaned
toward the former solutions and increase the PoP`s from northwest to
southeast Tuesday night into Wednesday.
The forecast beyond Wednesday remains a bit murky. The GFS is
slowing down a bit but remains much more progressive with a broad
trough moving eastward into the Mississippi Valley. The ECMWF and
GEM only slowly break down the ridge and pretty much don`t get the
wave even into the area until mid to late weekend. The tropical
system moving offshore of the East Coast doesn`t help matters
either. Have kept most of the PoP`s focused on the period through
Friday, but confidence in this part of the forecast is lower than
usual.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 657 AM CDT SUN AUG 24 2014
Minor MVFR fog will affect CMI through 14z, otherwise VFR
conditions are expected at the other terminal sites this morning.
Very hot high pressure will keep most cloud cover to a minimum
today, with some scattered 1500-2500FT clouds at times. No rain or
storms are expected near any TAF sites over the next 24 hours, as
mid-level warming advances into IL and pushes the storm tracks
north and east of our area. Forecast soundings show some light
MVFR fog may redevelop near CMI again later tonight, with lower
confidence any other sites will see fog.
Winds this morning will start out east-southeast, then veer to the
south this afternoon. Tonight they are expected to settle into a
southeast direction. Wind speeds should remain less than 10kt due
to a very weak pressure gradient.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.
HEAT ADVISORY from Noon to 7 PM CDT Monday FOR ILZ029-031-037-
038-043>046-055-057.
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ036-040-041.
&&
$$
UPDATE...BARNES
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
207 PM EDT SUN AUG 24 2014
.SYNOPSIS...
A FRONTAL BOUNDARY PUSHES FARTHER SOUTH OF THE AREA TODAY AS HIGH
PRESSURE REMAINS OVER THE NORTHEAST STATES. THE HIGH WILL BUILD
SOUTH INTO THE MID ATLANTIC MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST SFC ANALYSIS REVEALS ~1021 MB HI PRES CENTERED OVR NEW
ENGLAND WITH A FRNTAL BNDRY DROPPING S THRU THE CAROLINAS.
ALOFT...NW FLOW CONTINUES WITH AN UPR-LEVEL RIDGE CENTERED OVR THE
E-CNTRL CONUS. CLOUDS CONTINUE TO SLOWLY MOVE WEST AND MOST
CLOUDINESS IS OVER THE WESTERN MOST COUNTIES. HOWEVER CAN SEE MORE
CU DEVELOPING AND COMING IN OFF THE OCEAN. LOOKING AT THE RAP AND
HRRR BUFKIT SOUNDINGS DOES SHOW MORE PARTLY SUNNY SKIES EAST AND
MADE SOME ADJUSTMENTS TO CLOUD COVER. HELD MAXES ALONG THE COAST
ONLY IN THE MID TO UPPER 70S THIS AFTERNOON. THE WAL SOUNDING
WOULD ONLY SUPPORT A HIGH IN THE MID 70S. WILL BE A LITTLE WARMER
INLAND WITH HIGHS REACHING THE LOW 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SHORT TERM PERIOD WILL BE CHARACTERIZED BY SFC HI PRES LOCKED IN
PLACE ALONG THE NE AND MID ATLANTIC CST...AND UPR-LEVEL RIDGING
ACROSS THE E HALF OF THE CONUS. THIS WILL LEAD TO DRY CONDITIONS
THE ENTIRE PERIOD WITH NE WINDS AND MSTLY SUNNY/CLEAR SKIES. BLO
NORMAL TEMPS WILL CONTINUE...WITH HIGHS MON AND TUE IN THE UPR 70S
TO MID 80S AND LOWS IN THE UPR 50S TO MID 60S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE WX PATTERN THROUGH THE MIDDLE OF NEXT WEEK WILL BE DOMINATED
BY SFC HIGH PRESSURE AND UPPER LEVEL RIDGING ALONG THE EASTERN
SEABOARD. THIS SHOULD KEEP ANY TROPICAL CYCLONE ACTIVITY SHUNTED
WELL SOUTH OF THE REGION THROUGH AT LEAST THURSDAY. THE RIDGING
PATTERN MID-WEEK WILL MAINTAIN A COOL AND DRY AIRMASS OVER THE
AREA THROUGH WED BEFORE THE RIDGE AXES AT THE SFC AND ALOFT ALOFT
BEGIN TO SHIFT EAST OF THE FA...AND MOVING OFFSHORE ON THU. TEMPS
WILL BE SLIGHTLY BELOW NORMAL TUE NIGHT THROUGH WED NIGHT (LOWS IN
THE 60S...UPPER 50S FAR WRN COUNTIES/HIGHS IN THE LOW-MID 80S...
MID-UPPER 70S BEACHES)...THEN SLOWLY MODERATE TWD SEASONAL NORMALS
THU/FRI (HIGHS IN THE MID-UPPER 80S...UPPER 70S-LOWER 80S
BEACHES/LOWS IN THE 60S...AROUND 70 BEACHES). PENDING WX FROM THU
INTO FRI WILL BE HIGHLY DEPENDENT ON TROPICAL ACTIVITY TIMING AND
PLACEMENT. UNCERTAINTY REMAINS HIGH AND PREFER NOT TO LEAN THE
FORECAST HEAVILY TWD ANY GIVEN SOLUTION AT THIS TIME.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
DRIER AIR CONTINUES TO OVERSPREAD THE AREA TODAY WITH VFR
CONDITIONS EXPECTED THROUGH THE 18Z TAF PERIOD. GUSTY NE WINDS
ALONG THE COAST BTWN 15-25 KTS WILL PERSIST DURING THE DAYLIGHT
HRS. SKC ALONG WITH DIMINISHING WINDS AFTER 00Z.
OUTLOOK...DRY WEATHER WITH VFR CONDITIONS EXPECTED FOR NEXT SEVERAL
DAYS AS MID AND LOWER RIDGING TAKES PLACE OVER THE AREA.
&&
.MARINE...
HIGH PRESSURE OVER NEW ENGLAND WILL CONTINUE TO BUILD SOUTH AND OVR
THE WATERS THROUGH MID WEEK. PERSISTENT NE FLOW AND TIGHTENING PRS
GRADIENT WILL KEEP SCA FLAGS FLYING TODAY. WINDS DIMINISH ACROSS THE
CHES BAY BY 00Z. MOUTH OF THE CHES BAY AND CURRITUCK SOUND RATHER
PROBLEMATIC AS WINDS REMAIN IN THE 15-20 KT RANGE ALONG WITH WAVES
AT THE MOUTH HOVERING ARND 4 FT THRU MON. EXTENDED HEADLINES OVER
THE COASTAL WATERS THRU MON NIGHT MAINLY FOR SEAS ARND 5 FT OUT
NEAR 20 NM.
NE FLOW BEGINS TO WANE BY TUESDAY AS HIGH PRESSURE MOVES FARTHER
AWAY FROM THE REGION. HOWEVER...UNCERTAINTY EXISTS IN SEA HEIGHT
FORECAST GIVEN INCREASED SWELL FROM A POTENTIAL TROPICAL SYSTEM
PROGGED TO PASS NEAR THE MID ATLANTIC COAST LATER THIS WEEK.
&&
.TIDES/COASTAL FLOODING...
THREAT NOW OVER FOR PAST HIGH TIDE CYCLE. LEWISETTA CAME IN JUST
BELOW THE MINOR FLOODING LEVEL AS TIDES JUMPED UP TO BETWEEN ONE
TO ONE AND A HALF FEET ABOVE NORMAL. TIDES FOR TODAYS HIGH TIDE
CYCLE PROGGED TO BE AROUND ONE FOOT ABOVE NORMAL...SO LEVELS SHOULD
REMAIN BELOW MINOR FLOODING THRESHOLDS THIS AFTN/EARLY EVENING.
LATEST DATA SUGGESTS ANOTHER ROUND OF LEVELS FALLING JUST SHORT
OF MINOR FLOODING AGAIN TONIGHT. THUS...ANOTHER ROUND OF
STATEMENTS MAY BE NEEDED THIS AFTN.
HIGH RIP CURRENT RISK NOW FOR ALL ATLANTIC BEACHES FROM OCEAN CITY
MD DOWN TO OUTER BANKS CURRITUCK NC. SEE CFWAKQ FOR DETAILS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MDZ025.
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ102.
VA...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR
VAZ098>100.
COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM EDT
MONDAY FOR VAZ077.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR ANZ633-634.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ632.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ630-
631-638.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR ANZ650-652-654-
656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/JAB
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...MPR/DAP
MARINE...MPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1223 PM EDT SUN AUG 24 2014
.SYNOPSIS...
A FRONTAL BOUNDARY PUSHES FARTHER SOUTH OF THE AREA TODAY AS HIGH
PRESSURE REMAINS OVER THE NORTHEAST STATES. THE HIGH WILL BUILD
SOUTH INTO THE MID ATLANTIC MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST SFC ANALYSIS REVEALS ~1021 MB HI PRES CENTERED OVR NEW
ENGLAND WITH A FRNTAL BNDRY DROPPING S THRU THE CAROLINAS.
ALOFT...NW FLOW CONTINUES WITH AN UPR-LEVEL RIDGE CENTERED OVR THE
E-CNTRL CONUS. CLOUDS CONTINUE TO SLOWLY MOVE WEST AND MOST
CLOUDINESS IS OVER THE WESTERN MOST COUNTIES. HOWEVER CAN SEE MORE
CU DEVELOPING AND COMING IN OFF THE OCEAN. LOOKING AT THE RAP AND
HRRR BUFKIT SOUNDINGS DOES SHOW MORE PARTLY SUNNY SKIES EAST AND
MADE SOME ADJUSTMENTS TO CLOUD COVER. HELD MAXES ALONG THE COAST
ONLY IN THE MID TO UPPER 70S THIS AFTERNOON. THE WAL SOUNDING
WOULD ONLY SUPPORT A HIGH IN THE MID 70S. WILL BE A LITTLE WARMER
INLAND WITH HIGHS REACHING THE LOW 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SHORT TERM PERIOD WILL BE CHARACTERIZED BY SFC HI PRES LOCKED IN
PLACE ALONG THE NE AND MID ATLANTIC CST...AND UPR-LEVEL RIDGING
ACROSS THE E HALF OF THE CONUS. THIS WILL LEAD TO DRY CONDITIONS
THE ENTIRE PERIOD WITH NE WINDS AND MSTLY SUNNY/CLEAR SKIES. BLO
NORMAL TEMPS WILL CONTINUE...WITH HIGHS MON AND TUE IN THE UPR 70S
TO MID 80S AND LOWS IN THE UPR 50S TO MID 60S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE WX PATTERN THROUGH THE MIDDLE OF NEXT WEEK WILL BE DOMINATED
BY SFC HIGH PRESSURE AND UPPER LEVEL RIDGING ALONG THE EASTERN
SEABOARD. THIS SHOULD KEEP ANY TROPICAL CYCLONE ACTIVITY SHUNTED
WELL SOUTH OF THE REGION THROUGH AT LEAST THURSDAY. THE RIDGING
PATTERN MID-WEEK WILL MAINTAIN A COOL AND DRY AIRMASS OVER THE
AREA THROUGH WED BEFORE THE RIDGE AXES AT THE SFC AND ALOFT ALOFT
BEGIN TO SHIFT EAST OF THE FA...AND MOVING OFFSHORE ON THU. TEMPS
WILL BE SLIGHTLY BELOW NORMAL TUE NIGHT THROUGH WED NIGHT (LOWS IN
THE 60S...UPPER 50S FAR WRN COUNTIES/HIGHS IN THE LOW-MID 80S...
MID-UPPER 70S BEACHES)...THEN SLOWLY MODERATE TWD SEASONAL NORMALS
THU/FRI (HIGHS IN THE MID-UPPER 80S...UPPER 70S-LOWER 80S
BEACHES/LOWS IN THE 60S...AROUND 70 BEACHES). PENDING WX FROM THU
INTO FRI WILL BE HIGHLY DEPENDENT ON TROPICAL ACTIVITY TIMING AND
PLACEMENT. UNCERTAINTY REMAINS HIGH AND PREFER NOT TO LEAN THE
FORECAST HEAVILY TWD ANY GIVEN SOLUTION AT THIS TIME.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
CURRENT TRENDS AND LATEST MODEL DATA IN DECENT AGREEMENT THAT THE
DRYER AIR CONTINUES TO OVERSPREAD THE AREA TODAY WITH ANY BKN SC
DECK SCATTERING OUT AFTER 18Z. FORECAST CONCERN WILL BE THE GUSTY
NE WINDS ALONG THE COAST. DATA SUGGESTS GUSTS BTWN 15-25 KTS ACROSS
THE SERN TAF SITES DURING THE DAYLIGHT HRS. SKC ALONG WITH DININISHING
WINDS AFTER 00Z.
OUTLOOK...DRY WEATHER WITH VFR CONDITIONS EXPECTED FOR NEXT SEVERAL
DAYS AS MID AND LOWER RIDGING TAKES PLACE OVER THE AREA.
&&
.MARINE...
HIGH PRESSURE OVER NEW ENGLAND WILL CONTINUE TO BUILD SOUTH AND OVR
THE WATERS THROUGH MID WEEK. PERSISTANT NE FLOW AND TIGHTENING PRS
GRADIENT WILL KEEP SCA FLAGS FLYING TODAY. WINDS DIMINISH ACROSS THE
CHES BAY BY 00Z. MOUTH OF THE CHES BAY AND CURRITUCK SOUND RATHER
PROBLEMATIC AS WINDS REMAIN IN THE 15-20 KT RANGE ALONG WITH WAVES
AT THE MOUTH HOVERING ARND 4 FT THRU MON. EXTENDED HEADLINES OVER
THE COASTAL WATERS THRU MON NIGHT MAINLY FOR SEAS ARND 5 FT OUT
NEAR 20 NM.
NE FLOW BEGINS TO WANE BY TUESDAY AS HIGH PRESSURE MOVES FARTHER
AWAY FROM THE REGION. HOWEVER...UNCERTAINITY EXISTS IN SEA HEIGHT
FORECAST GIVEN INCREASED SWELL FROM A POTENTIAL TROPICAL SYSTEM
PROGGED TO PASS NEAR THE MID ATLANTIC COAST LATER THIS WEEK.
&&
.TIDES/COASTAL FLOODING...
THREAT NOW OVER FOR PAST HIGH TIDE CYCLE. LEWISETTA CAME IN JUST
BELOW THE MINOR FLOODING LEVEL AS TIDES JUMPED UP TO BETWEEN ONE
TO ONE AND A HALF FEET ABOVE NORMAL. TIDES FOR TODAYS HIGH TIDE
CYCLE PROGGED TO BE AROUND ONE FOOT ABOVE NORMAL...SO LEVELS SHOULD
REMAIN BELOW MINOR FLOODING THRESHOLDS THIS AFTN/EARLY EVENING.
LATEST DATA SUGGESTS ANOTHER ROUND OF LEVELS FALLING JUST SHORT
OF MINOR FLOODING AGAIN TONIGHT. THUS...ANOTHER ROUND OF
STATEMENTS MAY BE NEEDED THIS AFTN.
HIGH RIP CURRENT RISK NOW FOR ALL ATLANTIC BEACHES FROM OCEAN CITY
MD DOWN TO OUTER BANKS CURRITUCK NC. SEE CFWAKQ FOR DETAILS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MDZ025.
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ102.
VA...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR
VAZ098>100.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR ANZ633-634.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ632.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ630-
631-638.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR ANZ650-652-654-
656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/JAB
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...MPR
MARINE...MPR
TIDES/COASTAL FLOODING...BMD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
344 PM EDT SUN AUG 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.
TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.
AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 343 PM EDT SUN AUG 24 2014
A TRANSITION TO A COOLER AND MAINLY DRIER PATTERN WL BE IN STORE
THIS WEEK AS THE UPPER PATTERN TRANSITIONS TO A LOWER AMPLITUDE/MORE
ZONAL FLOW ALONG THE CNDN BORDER. OVER THE PAST COUPLE OF DAYS...
THERE HAVE BEEN SOME MODEL DIFFERENCES ON WHETHER THERE WOULD BE
SOME INTERACTION BTWN THIS NRN BRANCH FLOW AND A WEAKER SRN STREAM
IN THE CONUS. ALTHOUGH THE TREND THRU MID WEEK IS FOR A MORE ROBUST
AND DRIER NRN STREAM FLOW...LONGER TERM MODEL DIFFERENCES AND
RUN-TO-RUN INCONSISTENCIES RETURN FOR LATER IN THE WEEK.
MON NGT...THE CWA WL BE UNDER A SLOWLY VEERING WSW FLOW ALF TO THE S
OF VIGOROUS SHRTWV MOVING EWD THRU FAR NW ONTARIO. ALTHOUGH
ATTENDANT COLD FNT OVER THE SE CWA WL BE WEAKENING...GUIDANCE HINTS
A SECOND COLD FNT PUSHED ALONG BY A TRAILING UPR DISTURBANCE THAT IS
EMBEDDED IN THE VEERING FLOW ALF AND STREAKING ACRS NRN LK SUP/
ADJOINING ONTARIO WILL SURGE ACRS THE CWA. COMBO OF DRY AIR ALF AND
DIURNAL COOLING WL LIMIT PCPN CHCS ASSOCIATED WITH THIS SECONDARY
COLD FROPA...BUT WL INCLUDE SOME LO CHC POPS OVER MAINLY THE E HALF
OF THE CWA CLOSER TO TRACK OF TRAILING SHRTWV AND/OR WEAKENING
PRIMARY FNT/LINGERING HIER H85 DEWPTS NEAR 12-14C UNDER AREA OF
DEEP...ALBEIT RATHER WEAK DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE
SECOND SHRTWV. THE 12Z NAM IS MOST AGGRESSIVE WITH THE LLVL COOLING
BEHIND THE FROPA...SHOWING H85 TEMPS FALLING AS LO AS 5C OVER THE
FAR NW BY 12Z TUE. SO MIN TEMPS WL BE QUITE A BIT LOWER THAN
TNGT...ESPECIALLY OVER THE WRN CWA.
TUE...HI PRES AND MUCH DRIER AIR WITH PWAT FALLING AS LO AS 0.50 TO
1.00 INCH OVER THE S WL ARRIVE ACRS UPR MI. ALTHOUGH THERE MAY BE
SOME MID/HI CLDS OVER MAINLY THE SRN TIER ASSOCIATED WITH A SRN
STREAM WEAK DISTURBANCE PASSING THRU THE LOWER LKS...GUIDANCE HINTS
THE AIRMASS BLO H7 WL BE TOO DRY FOR ANY PCPN SO FAR N OF SFC BNDRY
IN THE LOWER LKS. THE ONE EXCEPTION WAS THE 00Z CNDN MODEL WHICH
INDICATED THE DEEPER MSTR TO THE S WOULD RETURN FARTHER N AHEAD OF
YET ANOTHER SHRTWV MOVING ALONG THE CNDN BORDER AND BRING SOME PCPN
TO THE SE CWA...BUT THE 12Z VERSION HAS BACKED OFF ON THIS WETTER
SCENARIO. H85 TEMPS VARYING FM ARND 8C OVER THE NW TO ARND 13C OVER
THE SCNTRL WL SUPPORT HI TEMPS FM THE 60S NEAR LK SUP TO NEAR 80
WITH SOME DOWNSLOPING INTO MENOMINEE COUNTY.
TUE NGT/WED...BULK OF THE LONGER TERM MODELS INDICATE A MORE WNW
CONFLUENT FLOW ALF AHEAD OF SHRTWV RDG EMBEDDED IN THE NRN STREAM
ALONG THE CNDN BORDER WL BRING HI PRES/DRY AIR TO THE UPR LKS AND
SUPPRESS DEEPER MSTR TO THE S. THE 12Z CNDN MODEL DOES HINT AT SOME
MID/HI CLDS LINGERING INTO WED ON THE NRN EDGE OF SHRTWV PASSING TO
THE S IN THE SRN STREAM...BUT ITS FCST LLVLS ARE TOO DRY FOR PCPN.
TUE NGT WL BE PLEASANTLY COOL AS H85 TEMPS ARE FCST TO BE ARND
8C/PWAT 0.50-0.75 INCH. WITH DRY AIR AND H85 TEMPS IN THE 8-10C
RANGE ON WED...EXPECT MOSUNNY CONDITIONS AND HI TEMPS IN THE LO 70S
OVER THE INTERIOR AWAY FM LK MODERATION.
WED NGT/THU...DRY HI PRES SHIFTING TO OVER SE ONTARIO IS FCST TO
DOMINATE AND BRING CONTINUED DRY WX TO UPR MI. AFTER ANOTHER COOL
NGT...TEMPS ON THU SHOULD BE A FEW DEGREES HIER THAN ON WED AS H85
TEMPS REBOUND TO 10-12C IN LGT RETURN SSW FLOW ARND DEPARTING SFC HI
PRES.
EXTENDED...SHRTWV/DEEPER MSTR ASSOCIATED WITH SRN BRANCH FLOW IS
FCST TO AT LEAST SKIRT THE SRN TIER OF THE CWA IN THE THU NGT TO FRI
NGT TIME PERIOD BEFORE A COLD FNT ASSOCIATED WITH A SHRTWV MOVING
THRU THE WNW NRN BRANCH FLOW CROSSES UPR MI ON SAT AND DRIVES THIS
MSTR TO THE S. GIVEN SOME TIMING/TRACK DIFFERENCES ON VARIOUS
SHRTWVS...WL CARRY NO MORE THAN THE CONSENSUS LO CHC POPS. DRY WX
SHOULD BE THE RULE NEXT SUN WITH HI PRES FOLLOWING THE SAT FROPA.
TEMPS DURING THIS TIME ARE LIKELY TO RUN AOB NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 223 PM EDT SUN AUG 24 2014
WHILE DAYTIME HEATING HAS BEEN EFFECTIVE AT BRINGING HIGH END MVFR
TO VFR CONDITIONS TO IWD AND CMX. OTHERWISE...PERSISTENT S-SE WINDS
HAVE KEEP MVFR CLINGS GOING A BIT LONGER AT SAW. LOOK FOR SOME
IMPROVEMENT AT SAW THIS AFTERNOON. THE MAIN STORY FOR THIS TAF
PERIOD WILL BE THE NEARING COLD FRONT COLD FRONT APPROACHING FROM
THE W LATE THIS EVENING...BRINGING SHRA/TSRA TO W UPPER MI. KEPT A
MENTION OF VCTS AT KIWD...AS TS ACTIVITY SHOULD BE DIMINISHING
OVERNIGHT DUE TO DECREASING INSTABILITY. ONLY -SHRA HAVE BEEN
INCLUDED AT CMX FROM 06-10Z...NO TS. PLENTY OF MOISTURE WILL REMAIN
WITH UPSLOPE CONDITIONS BRINGING ANOTHER ROUND OF MAINLY MVFR
CEILINGS TO SAW OVERNIGHT. OTHERWISE...LOOK FOR SLOWLY IMPROVING
CONDITIONS W TO E ON MONDAY AS DRIER AIR WORKS IN FROM THE W BEHIND
THE EXITING COLD FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KC
AVIATION...KF
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
224 PM EDT SUN AUG 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.
TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.
AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 354 AM EDT SUN AUG 24 2014
AFTER A VERY CLOUDY PERIOD OVER THE UPPER GREAT LAKES REGION OVER
THE LAST 7-9 DAYS...EXPECT A TRANSITION TO DRIER...COOLER AND MORE
SUNSHINE FOR THE MIDDLE OF THE WORK WEEK.
THE TRANSITION WILL BE LED BY A COLD FRONT THAT WILL BE MOVING
THROUGH THE CWA MONDAY MORNING AND EARLY AFTERNOON. THIS FRONT IS
ASSOCIATED WITH 1002MB LOW PRESSURE SYSTEM THAT WILL BE MOVING FROM
NEAR LAKE WINNIPEG ON MONDAY MORNING TO JAMES BAY ON MONDAY NIGHT.
AS THIS OCCURS...AN OCCLUDED FRONT WILL STRETCH EAST INTO NORTHERN
ONTARIO AND THEN A COLD FRONT STRETCHING SOUTH ACROSS WEST/CENTRAL
LAKE SUPERIOR AND UPPER MICHIGAN AROUND 12Z ON MONDAY. EXPECT
SHOWERS AND THUNDERSTORMS TO BE ONGOING MONDAY MORNING ALONG THE
FRONT AND SHIFTING EAST THROUGH THE MORNING AND EARLY AFTERNOON
HOURS. CURRENT FORECAST CALLS FOR THE FRONT AND ASSOCIATED
SHOWERS/THUNDERSTORMS TO BE EXITING THE EASTERN CWA TOWARDS THE LATE
AFTERNOON. WHILE THERE IS HIGH CONFIDENCE ON THE TIMING OF THE COLD
FRONT MOVING THROUGH (ALTHOUGH 00Z NAM HAS SLOWED THE FRONT
DOWN A FEW HOURS)...THE AMOUNT OF SHOWERS/THUNDERSTORMS ALONG THE
FRONT IS UNCERTAIN DUE TO SEVERAL LIMITATIONS. THESE LIMITATIONS
INCLUDE THE TIME OF DAY THE FRONT IS MOVING THROUGH...MUCH OF THE
FORCING FROM THE UPPER TROUGH AND SHORTWAVES WELL TO THE NORTHWEST
AND NEAR THE SURFACE LOW...ALONG WITH LIMITED MOISTURE AND WEAK
LAPSE RATES (AROUND 6C/KM) IN THE MID LEVELS. IN ADDITION...A NOSE
OF DRY AIR MOVING IN BETWEEN 900-700MB WILL HELP TO LIMIT ANY
SURFACE OR LOW LEVEL DEVELOPMENT. THESE FACTORS COMBINE TO KEEP POPS
ON THE LOW END OF CHANCES AS THE FRONT MOVES THROUGH AND THINK THE
BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS WILL COME FROM ANY
ONGOING STORMS MOVING INTO THE AREA FROM THE WEST TONIGHT AND TRYING
TO HOLD TOGETHER INTO MONDAY. IF SOMETHING CAN HOLD TOGETHER OR GET
GOING AS THE FRONT MOVES INTO THE EASTERN CWA MONDAY
AFTERNOON...THERE COULD BE STRONG THUNDERSTORMS WITH INSTABILITY ON
THE INCREASE (MU/ML CAPES INCREASING TO 500-1500 J/KG) AND 0-6KM
SHEAR VALUES AROUND 35KTS (OR 25-30KTS OF EFFECTIVE BASED OFF
POTENTIAL FOR ELEVATED THUNDERSTORMS). WEST OF THE COLD FRONT ON
MONDAY...WILL SEE MUCH DRIER AIR MOVING IN AND DEWPOINTS FALLING
INTO THE 50S AND SKIES BECOMING MOSTLY SUNNY.
THE LOW LEVEL WEDGE OF DRY AIR WILL REMAIN INTO MONDAY NIGHT
(PRODUCING PARTLY CLOUDY TO MOSTLY CLEAR SKIES) BEFORE 925-700MB
WINDS TURN MORE TO THE WEST AND EVENTUALLY WEST-NORTHWEST AS A
SECONDARY FRONT/TROUGH MOVES THROUGH. THERE COULD BE SOME SHOWERS
OVER THE SOUTHEAST CWA WITH THIS SECONDARY FRONT AND CLOSER TO
LINGERING MOISTURE FROM THE FIRST FRONT. BEHIND THE SECONDARY
FRONT...MODELS ARE INDICATING AN INCREASE IN 925-850MB MOISTURE
THAT WILL LEAD TO DIURNAL CLOUD DEVELOPMENT DURING THE DAY ON
TUESDAY OVER THE NORTH HALF OF THE LAND CWA EVEN THOUGH A HIGH
PRESSURE RIDGE (FROM A HIGH IN THE EASTERN DAKOTAS) WILL NOSE EAST
OVER THE WESTERN HALF OF THE CWA. FARTHER SOUTH...WOULD EXPECT
MOSTLY SUNNY SKIES AS THE COLD FRONT LOOKS TO SLIDE FAR ENOUGH SOUTH
INTO LOWER MICHIGAN AND SOUTHERN WISCONSIN TO KEEP ANY SHOWERS TO
THE SOUTH OF THE AREA. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES
COOLER ON TUESDAY THAN MONDAY...WITH HIGHS INT HE MID 70S OVER THE
SOUTHEAST HALF AND UPPER 60S OVER THE WEST NEAR LAKE SUPERIOR.
WITH THE FLOW BECOMING ZONAL FOR THE MIDDLE OF THE UPCOMING WORK
WEEK AND THE MAIN SHORTWAVES STAYING NORTH OF THE CWA AND MOVING
ACROSS NORTHERN ONTARIO...EXPECT THE HIGH PRESSURE TO FOLLOW THE
RIDGE EASTWARD WEDNESDAY INTO THURSDAY. THIS WILL PRODUCE DRY
WEATHER AND WITH 850MB TEMPS SLIGHTLY BELOW NORMAL (AROUND
9C) EXPECT HIGHS TO BE SIMILAR WITH RESPECT TO NORMAL. WILL MENTION
THAT THE SOUTH CENTRAL CWA COULD BE BRUSHED BY A FEW WEAK WAVES
RUNNING ALONG THAT FRONT TO THE SOUTH OF THE AREA ON TUESDAY
AND AGAIN THURSDAY...BUT WOULDN/T EXPECT MORE THAN A STRAY SHOWER.
THE HIGH PRESSURE RIDGE WILL BEGIN TO SLIDE EAST ON FRIDAY WHILE AN
UPPER TROUGH SEPARATED FROM THE NORTHERN STREAM FLOW SLIDES EAST
INTO THE CENTRAL PLAINS. THIS WAVE WILL DEVELOP A WEAK SURFACE LOW
IN THE CENTRAL PLAINS AND SLIDE EAST-NORTHEAST THROUGH THE GREAT
LAKES REGION FRIDAY AFTERNOON INTO FRIDAY NIGHT. 00Z GEM
IS CONSISTENT WITH PREVIOUS RUNS AND 00Z ECMWF ON A SLOWER
ARRIVAL WITH THE UPPER TROUGH AND SURFACE LOW...WHILE THE 00Z GFS
LOOKS TO HAVE CONVECTIVE FEEDBACK ISSUES IN THE CENTRAL PLAINS ON
MONDAY/TUESDAY EVENING WHICH SPEEDS UP THE UPPER TROUGH AND
PUSHES IT THROUGH 12-24HRS EARLIER. FEEL A GENERAL CONSENSUS AND
FOCUS TOWARDS THE ECMWF (AND THE MATCHING TIMING WITH THE GEM) IS A
GOOD MIDDLE POINT RIGHT NOW AND WILL FOLLOW THAT IDEA. THIS WAVE
WILL SHIFT EAST OF THE AREA ON SATURDAY AND LEAD TO DRY WEATHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 223 PM EDT SUN AUG 24 2014
WHILE DAYTIME HEATING HAS BEEN EFFECTIVE AT BRINGING HIGH END MVFR
TO VFR CONDITIONS TO IWD AND CMX. OTHERWISE...PERSISTENT S-SE WINDS
HAVE KEEP MVFR CLINGS GOING A BIT LONGER AT SAW. LOOK FOR SOME
IMPROVEMENT AT SAW THIS AFTERNOON. THE MAIN STORY FOR THIS TAF
PERIOD WILL BE THE NEARING COLD FRONT COLD FRONT APPROACHING FROM
THE W LATE THIS EVENING...BRINGING SHRA/TSRA TO W UPPER MI. KEPT A
MENTION OF VCTS AT KIWD...AS TS ACTIVITY SHOULD BE DIMINISHING
OVERNIGHT DUE TO DECREASING INSTABILITY. ONLY -SHRA HAVE BEEN
INCLUDED AT CMX FROM 06-10Z...NO TS. PLENTY OF MOISTURE WILL REMAIN
WITH UPSLOPE CONDITIONS BRINGING ANOTHER ROUND OF MAINLY MVFR
CEILINGS TO SAW OVERNIGHT. OTHERWISE...LOOK FOR SLOWLY IMPROVING
CONDITIONS W TO E ON MONDAY AS DRIER AIR WORKS IN FROM THE W BEHIND
THE EXITING COLD FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...KF
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1225 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 1225 PM CDT SUN AUG 24 2014
MADE SOME FURTHER ADJUSTMENTS TO POPS/WX AS MOST OF THE PRECIP HAS
MOVED NORTH AND EAST OF THE CWA BUT MORE CONVECTION SEEMS TO BE
DEVELOPING IN THE DEVILS LAKE BASIN. SOME CLEARING BUT SKIES
REMAIN MOSTLY CLOUDY OVER A LARGE PORTION OF OUR AREA. WILL KEEP
AN EYE OUT FOR ADDITIONAL CLEARING AND IF ANY STRONG TO SEVERE
CONVECTION BREAKS OUT.
UPDATE ISSUED AT 949 AM CDT SUN AUG 24 2014
UPDATED POPS/WX FOR CURRENT RADAR TRENDS. CONVECTION NOW LIMITED
TO THE NORTHERN VALLEY AND A FEW ISOLATED CELLS POPPING UP FURTHER
SOUTH. MUCH OF THE DEVELOPMENT IN THE NEXT FEW HOURS WILL DEPEND
ON CLOUD COVER. THERE IS SOME DECENT CLEARING IN THE SOUTH CENTRAL
CWA...SO THERE COULD BE SOME DESTABILIZATION. RAP AND HRRR HAVE
REDEVELOPMENT MAINLY OVER THE NORTHERN COUNTIES IN THE 20-00Z TIME
FRAME THIS AFTERNOON. WILL CONTINUE TO KEEP SCATTERED POPS GOING
FOR MUCH OF THE DAY...ALTHOUGH SEVERITY IS STILL UNCERTAIN AT THIS
POINT SO WILL LEAVE OUT OF THE GRIDS UNTIL A LATER UPDATE. WILL
KEEP TEMPS ON TRACK TO TOP OUT IN THE 70S TO LOW 80S.
UPDATE ISSUED AT 635 AM CDT SUN AUG 24 2014
RADAR CURRENTLY SHOWING CLUSTER OF THUNDERSTORMS AND HEAVY RAIN
SHOWERS MAINLY NORTH OF HWY 2 CORRIDOR IN THE RED RIVER VALLEY AND
NORTHWEST MINNESOTA...AS WELL AS DOWN THROUGH BELTRAMI COUNTY.
SEEING SOME ISOLATED TSTM ACTIVITY BEHIND MAIN CLUSTER IN EASTERN
ND. HAVE UPDATED POP GRIDS TO REFLECT THIS. NO OTHER CHANGES MADE
THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 357 AM CDT SUN AUG 24 2014
CURRENT RADAR SHOWS A LINE OF THUNDERSTORMS FROM CENTRAL CASS
COUNTY THROUGH CENTRAL OTTER TAIL COUNTY MOVING NORTHWARD INTO WEST
CENTRAL AND NORTHWEST MINNESOTA AS WELL AS CONTINUING ACROSS FAR
EASTERN NORTH DAKOTA...ESPECIALLY BARNES...RANSOM...SARGENT AND
RICHLAND COUNTIES. THOSE FOUR COUNTIES HAVE RECEIVED THE MOST
PRECIPITATION BUT REMAIN BELOW FLASH FLOOD GUIDANCE AND A
HEADLINES FOR WIDESPREAD OVERLAND FLOODING IS NOT EXPECTED HOWEVER
LOCALIZED LOW AREAS COULD SEE STANDING WATER TOMORROW MORNING.
CURRENTLY THE HI RES MODELS HAVE THE BEST HANDLE ON THE
PRECIPITATION AND WILL BE USED THROUGH AROUND 18Z...WHEN THE
PRECIPITATION SHOULD LIFT OUT OF THE REGION AS THE LOW MOVES NORTH
AND A DRY SLOT MOVES INTO MY SOUTHWESTERN ZONES.
TODAY...DRY SLOT WILL MOVE ACROSS THE SOUTHERN VALLEY AND
PRECIPITATION SHOULD BE CONFINED TO MAINLY NORTH OF THE HWY 2
CORRIDOR AND THE FAR EAST. SOME MODELS DO SHOW CU/SHOWERS
DEVELOPING IN THE DRY SLOT BY LATE AFTN AND WILL KEEP SOME LOW
POPS IN MY SOUTHWESTERN ZONES. A SFC BNDRY STRETCHED FROM THE DVL
REGION INTO THE BJI AREA COULD BE THE SOURCE OF STRONG TO POSSIBLY
SEVERE THUNDERSTORMS IN THE NORTHERN VALLEY AND NW MINNESOTA THIS
AFTN...AS HEATING BECOMES MAXIMIZED AND DEEP LAYERED SHEAR
INCREASES TO AROUND 40 KTS BY 21Z. THERE WILL BE ONLY A SMALL
OPPORTUNITY TO HEAT OUT THIS AFTN...SO ATTM CONFIDENCE FOR SVR IS
LOW BUT STILL POSSIBLE. SPC HAS A SLIGHT RISK OUT FOR THIS REGION.
TONIGHT....PRECIP SHOULD BE CONFINED TO ALONG OR NORTH OF THE
INTERNATIONAL BORDER AND SOME LINGERING ISOLATED SHOWERS IN THE
FAR EAST. LOW WILL CONTINUE TO PULL NORTH AND PRECIP SHOULD END BY
MONDAY MORNING. A QUITE COOL AIRMASS WILL THEN WRAP INTO EASTERN
ND AS THE LOW PULLS NORTH...AND OVERNIGHT LOWS COULD DROP INTO THE
40S FOR PARTS OF THE FAR WESTERN CWA.
MONDAY...STRONG COLD ADVECTION INTO THE NORTHERN TIER WILL KEEP
DAYTIME HIGHS WELL BELOW SEASONAL NORMS...WITH THE DEVILS LAKE
BASIN STRUGGLING TO BREAK THE 60 MARK AND MOST OF THE REST OF THE
AREA SEEING DAYTIME HIGHS IN THE MID 60S TO NEAR 70. WINDS WILL BE
WESTERLY AND BREEZY...MAKING A RATHER CHILLY DAY FOR AUGUST. SOME
SHOWERS MAY LINGER ALONG THE INTL BORDER AS THE SFC LOW MOVES INTO
WRN ONTARIO AND HAVE KEPT LOW POPS ACROSS THE EXTREME NORTH.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 357 AM CDT SUN AUG 24 2014
TUESDAY...UNSEASONALLY COOL TEMPERATURES WILL STAY IN PLACE
THROUGH TUESDAY AS SFC HIGH PRESSURE MOVES INTO THE AREA. DAYTIME
HIGHS WILL BE IN THE MID TO UPPER 60S.
BEYOND TUESDAY...LONG WAVE PATTERN FORECAST A ZONAL FLOW ACROSS SOUTHERN
CANADA DURING THIS PERIOD. THE ECMWF IS A FASTER SOLUTION THAN THE
GFS THROUGH THE PERIOD. ECMWF AND GFS HAS BEEN TRENDING SOUTH OVER
THE LAST COUPLE MODEL RUNS. WILL BLEND THE ECMWF AND GFS.
TRIMMED BACK POPS IN FAR SOUTHERN GRANT COUNTY WED AND WED NIGHT.
WILL SHIFT PRECIP EAST ON SAT.
LITTLE CHANGE TO TEMPS...A DEGREE OR SO HIGHER FOR WED AND SAT. NO
CHANGES TO THU OR FRI FROM YESTERDAYS RUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1225 PM CDT SUN AUG 24 2014
EXPECT SOME MVFR/IFR CIGS BEFORE THE TROUGH MOVES THROUGH AND SHIFTS
WINDS MORE SW. ONCE WINDS TURN SW...EXPECT VFR CONDITIONS EXCEPT
NEAR ANY SHOWER/TSTORM THIS AFTERNOON MAINLY IN THE NORTH. WINDS
COULD GUST TO AROUND 25KT THROUGH THIS EVENING...DECREASE SOME
OVERNIGHT...THEN SHIFT MORE WESTERLY ON MONDAY. WINDS COULD ONCE
AGAIN BECOME A BIT GUSTY TO AROUND 25KT LATE IN THE TAF
PERIOD...WITH MVFR CIGS POSSIBLE IN CYCLONIC FLOW ALOFT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...SPEICHER
LONG TERM...HOPPES/SPEICHER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
144 PM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE OVER QUEBEC WILL BUILD SOUTH ACROSS THE EASTERN GREAT
LAKES THEN DRIFT TOWARD THE MID ATLANTIC COAST THROUGH TUESDAY.
LOW PRESSURE WILL PASS NORTH OF THE GREAT LAKES TUESDAY WITH A
FRONTAL BOUNDARY SLOWLY SINKING SOUTH ACROSS THE AREA THROUGH THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRATUS DECK IN NW OHIO CONTINUES TO GRADUALLY ERODE AROUND THE
EDGES. UNFORTUNATELY IT WILL STILL TAKE A FEW MORE HOURS FOR THIS
TO REACH SANDUSKY/SENECA COUNTIES. IN THE EAST...THE 12Z PBZ
SOUNDING DID SHOW A HIGH AMOUNT OF LOW LEVEL MOISTURE THROUGH
2000 FEET BENEATH A VERY DRY LAYER ALOFT. CLOUDS HAVE FILLED IN
BUT WILL START TO MIX INTO THIS DRIER AIR AND START TO SCATTER OUT
BY 3-4 PM. LAST COUPLE RUNS OF THE RUC HAVE BEEN DOING A BETTER
JOB WITH THE CLOUD COVER ACROSS NE OHIO/NW PA AND AGREE WITH THAT TIMING.
GIVEN THE OVERCAST CONDITIONS IN MANY AREAS...ADJUSTED THE
FORECAST TO READ MOSTLY CLOUDY FOR PORTIONS OF NE OHIO/NW PA. ALSO
LOWERED HIGHS A COUPLE DEGREES IN THE WESTERN AND EASTERN PORTION
OF THE FORECAST AREA WITH HIGHS OCCURRING LATE THIS AFTERNOON AS
CLOUDS START TO CLEAR AT MANY SITES.
PREVIOUS DISCUSSION...
UPPER LEVEL HIGH PRESSURE WILL BUILD OVER THE REGION TODAY AS A
SURFACE HIGH DRIFTS SLOWLY SOUTHWARD OVER THE EASTERN GREAT LAKES
FROM QUEBEC. THIS SHOULD MEAN SINKING AIR OVER MOST OF THE REGION.
HOWEVER WE WILL NEED TO MONITOR AN AREA OF CONVERGENCE THAT WILL
SET UP ACROSS THE WESTERN COUNTY WARNING AREA FROM SANDUSKY TO
NEAR FINDLAY. IF THE AFTERNOON HEATING AND CONVERGENCE ALONG THIS
BOUNDARY ARE ENOUGH THERE MAY BE AN ISOLATED STORM OR TWO.
OTHERWISE WE WILL ERODE THE LOW LEVEL STRATOCUMULUS THIS MORNING
THEN WARM THE REGION UP WITH HIGHS A COUPLE DEGREES WARMER THAN
YESTERDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THE UPPER LEVEL RIDGE WILL SLOWLY WEAKEN INTO WEDNESDAY AS SURFACE
HIGH PRESSURE SETTLES TO THE MIDDLE ATLANTIC STATES. THIS SHOULD
ALLOW FOR AN INCREASE IN MOISTURE AND HEAT INTO THE REGION. HAVE
NUDGED HIGHS UP A COUPLE DEGREES FROM WHAT GUIDANCE IS INDICATING.
THIS WILL ALLOW PORTIONS OF THE REGION TO MAKE A RUN AT 90 DEGREES
FOR TUESDAY INTO WEDNESDAY AS LONG AS ANY CONVECTIVE DEBRIS
CLOUDINESS REMAINS THIN AND SCATTERED.
THUNDERSTORM CHANCES WILL SLOWLY INCREASE TUESDAY INTO WEDNESDAY.
TUESDAY MAY SEE CONVECTION DEVELOP ALONG A LAKE BREEZE. THE BEST
CONVERGENCE ALONG THIS BOUNDARY WILL BE FROM JUST EAST OF
CLEVELAND INTO NW PA. BY WEDNESDAY A COLD FRONT MAY BE CLOSE
ENOUGH TO BRING THUNDERSTORMS TO THE REGION DURING THE AFTERNOON
AND OVERNIGHT. LAST LOOK AT THE ECMWF INDICATES THAT THIS FRONT
MAY MOVE THROUGH FASTER. WILL HAVE TO MONITOR THIS THE NEXT
COUPLE DAYS AND TWEAK THE TIMING OF THE THUNDERSTORMS ON WEDNESDAY
AS NEEDED.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE MODELS ARE MORE IN AGREEMENT IN MOVING A WAVE ALONG THE FRONT
STALLED OVER THE AREA THU THRU FRI WITH THE GFS BEING A LITTLE
MORE PROGRESSIVE WITH THE FRONT. WILL KEEP A GOOD CHANCE FOR
SHRA/TSRA GOING THU AND FRI THEN SHOW SOME DECREASE IN POP FOR SAT
IN CASE THE GFS IS MORE RIGHT. EVEN THE ECMWF DOES SHOW A DECREASE
IN MOISTURE OVER THE AREA BY LATE SAT. TEMPS WILL BE TRICKY DUE TO
THE ULTIMATE POSITION OF THE FRONT AND WIND DIRECTION.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
PATCHES OF MVFR STRATOCUMULUS (BKN020-BKN030) WILL SLOWLY LIFT TO
VFR LAYER AND SCATTER OUT THIS AFTERNOON. PATCHES OF MVFR AND IFR
STRATOCUMULUS DECK WILL REDEVELOP LATE TONIGHT AND MONDAY MORNING
AS THE BOUNDARY LAYER REMAINS MOIST. FOG MAY GET IFR DENSE IN SOME
AREAS ESPECIALLY ACROSS NORTH CENTRAL OHIO AND NORTHWEST OHIO
EARLY MONDAY MORNING. MORE OF THE SAME ON MONDAY WITH MVFR
CEILINGS LIFTING TO VFR AND SCATTERING OUT.
OUTLOOK...VFR EXCEPT FOR MORNING FOG TUESDAY. NON VFR POSSIBLE
WEDNESDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
ENE WINDS OF 10 TO 20 KNOTS SHOULD SETTLE DOWN A LITTLE TODAY SO
NEAR SCA WAVES OF 2 TO 4 FEET SHOULD SUBSIDE TO 1 TO 3 FEET. WINDS
MAY PICK BACK UP A LITTLE THIS EVENING BUT THEN SHOULD START TURNING
SE AS THE HIGH OVER NY STATE DRIFTS SE TO THE NJ COAST FOR MON.
WINDS WILL VEER TO S TO SW FOR TUE AHEAD OF AN APPROACHING COLD
FRONT. RIGHT NOW IT LOOKS LIKE THE COLD FRONT WILL SAG INTO LAKE
ERIE BY LATE WED OR WED NIGHT THEN STALL AS A WAVE OF LOW PRESSURE
MOVES ALONG THE FRONT. WINDS ARE EXPECTED TO STAY 15 KNOTS OR LESS
BUT WIND DIRECTION IS IN QUESTION DUE TO THE UNCERTAINTY OF THE
EXACT POSITION OF THE FRONT WED NIGHT THRU THU.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MULLEN
NEAR TERM...KEC/MULLEN
SHORT TERM...MULLEN
LONG TERM...ADAMS
AVIATION...KOSARIK
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1232 PM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE OVER QUEBEC WILL BUILD SOUTH ACROSS THE EASTERN GREAT
LAKES THEN DRIFT TOWARD THE MID ATLANTIC COAST THROUGH TUESDAY.
LOW PRESSURE WILL PASS NORTH OF THE GREAT LAKES TUESDAY WITH A
FRONTAL BOUNDARY SLOWLY SINKING SOUTH ACROSS THE AREA THROUGH THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRATUS DECK IN NW OHIO CONTINUES TO GRADUALLY ERODE AROUND THE
EDGES. UNFORTUNATELY IT WILL STILL TAKE A FEW MORE HOURS FOR THIS
TO REACH SANDUSKY/SENECA COUNTIES. IN THE EAST...THE 12Z PBZ
SOUNDING DID SHOW A HIGH AMOUNT OF LOW LEVEL MOISTURE THROUGH
2000 FEET BENEATH A VERY DRY LAYER ALOFT. CLOUDS HAVE FILLED IN
BUT WILL START TO MIX INTO THIS DRIER AIR AND START TO SCATTER OUT
BY 3-4 PM. LAST COUPLE RUNS OF THE RUC HAVE BEEN DOING A BETTER
JOB WITH THE CLOUD COVER ACROSS NE OHIO/NW PA AND AGREE WITH THAT TIMING.
GIVEN THE OVERCAST CONDITIONS IN MANY AREAS...ADJUSTED THE
FORECAST TO READ MOSTLY CLOUDY FOR PORTIONS OF NE OHIO/NW PA. ALSO
LOWERED HIGHS A COUPLE DEGREES IN THE WESTERN AND EASTERN PORTION
OF THE FORECAST AREA WITH HIGHS OCCURRING LATE THIS AFTERNOON AS
CLOUDS START TO CLEAR AT MANY SITES.
PREVIOUS DISCUSSION...
UPPER LEVEL HIGH PRESSURE WILL BUILD OVER THE REGION TODAY AS A
SURFACE HIGH DRIFTS SLOWLY SOUTHWARD OVER THE EASTERN GREAT LAKES
FROM QUEBEC. THIS SHOULD MEAN SINKING AIR OVER MOST OF THE REGION.
HOWEVER WE WILL NEED TO MONITOR AN AREA OF CONVERGENCE THAT WILL
SET UP ACROSS THE WESTERN COUNTY WARNING AREA FROM SANDUSKY TO
NEAR FINDLAY. IF THE AFTERNOON HEATING AND CONVERGENCE ALONG THIS
BOUNDARY ARE ENOUGH THERE MAY BE AN ISOLATED STORM OR TWO.
OTHERWISE WE WILL ERODE THE LOW LEVEL STRATOCUMULUS THIS MORNING
THEN WARM THE REGION UP WITH HIGHS A COUPLE DEGREES WARMER THAN
YESTERDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THE UPPER LEVEL RIDGE WILL SLOWLY WEAKEN INTO WEDNESDAY AS SURFACE
HIGH PRESSURE SETTLES TO THE MIDDLE ATLANTIC STATES. THIS SHOULD
ALLOW FOR AN INCREASE IN MOISTURE AND HEAT INTO THE REGION. HAVE
NUDGED HIGHS UP A COUPLE DEGREES FROM WHAT GUIDANCE IS INDICATING.
THIS WILL ALLOW PORTIONS OF THE REGION TO MAKE A RUN AT 90 DEGREES
FOR TUESDAY INTO WEDNESDAY AS LONG AS ANY CONVECTIVE DEBRIS
CLOUDINESS REMAINS THIN AND SCATTERED.
THUNDERSTORM CHANCES WILL SLOWLY INCREASE TUESDAY INTO WEDNESDAY.
TUESDAY MAY SEE CONVECTION DEVELOP ALONG A LAKE BREEZE. THE BEST
CONVERGENCE ALONG THIS BOUNDARY WILL BE FROM JUST EAST OF
CLEVELAND INTO NW PA. BY WEDNESDAY A COLD FRONT MAY BE CLOSE
ENOUGH TO BRING THUNDERSTORMS TO THE REGION DURING THE AFTERNOON
AND OVERNIGHT. LAST LOOK AT THE ECMWF INDICATES THAT THIS FRONT
MAY MOVE THROUGH FASTER. WILL HAVE TO MONITOR THIS THE NEXT
COUPLE DAYS AND TWEAK THE TIMING OF THE THUNDERSTORMS ON WEDNESDAY
AS NEEDED.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE MODELS ARE MORE IN AGREEMENT IN MOVING A WAVE ALONG THE FRONT
STALLED OVER THE AREA THU THRU FRI WITH THE GFS BEING A LITTLE
MORE PROGRESSIVE WITH THE FRONT. WILL KEEP A GOOD CHANCE FOR
SHRA/TSRA GOING THU AND FRI THEN SHOW SOME DECREASE IN POP FOR SAT
IN CASE THE GFS IS MORE RIGHT. EVEN THE ECMWF DOES SHOW A DECREASE
IN MOISTURE OVER THE AREA BY LATE SAT. TEMPS WILL BE TRICKY DUE TO
THE ULTIMATE POSITION OF THE FRONT AND WIND DIRECTION.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THE FOG AND STRATUS WILL BURN OFF BY 14 OR 15Z AT THE LATEST. LOW
LEVEL MOISTURE OVER THE EAST HALF OF THE AREA MAY KEEP THE DAYTIME
CU FIELD IN THE MVFR RANGE WHILE THE WEST SHOULD SEE THE CU AT VFR
LEVELS BY AFTERNOON. SOME HIGHER CLOUDS WILL ALSO BE SPREADING WEST
TO EAST OVER THE AREA TODAY AND TONIGHT. THESE ADDED HIGHER CLOUDS
AND JUST ENOUGH WIND SHOULD HELP TO LIMIT DENSE FOG DEVELOPMENT LATE
TONIGHT.
OUTLOOK...VFR EXCEPT FOR MORNING FOG TUESDAY. NON VFR POSSIBLE
WEDNESDAY AND THURSDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
ENE WINDS OF 10 TO 20 KNOTS SHOULD SETTLE DOWN A LITTLE TODAY SO
NEAR SCA WAVES OF 2 TO 4 FEET SHOULD SUBSIDE TO 1 TO 3 FEET. WINDS
MAY PICK BACK UP A LITTLE THIS EVENING BUT THEN SHOULD START TURNING
SE AS THE HIGH OVER NY STATE DRIFTS SE TO THE NJ COAST FOR MON.
WINDS WILL VEER TO S TO SW FOR TUE AHEAD OF AN APPROACHING COLD
FRONT. RIGHT NOW IT LOOKS LIKE THE COLD FRONT WILL SAG INTO LAKE
ERIE BY LATE WED OR WED NIGHT THEN STALL AS A WAVE OF LOW PRESSURE
MOVES ALONG THE FRONT. WINDS ARE EXPECTED TO STAY 15 KNOTS OR LESS
BUT WIND DIRECTION IS IN QUESTION DUE TO THE UNCERTAINTY OF THE
EXACT POSITION OF THE FRONT WED NIGHT THRU THU.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MULLEN
NEAR TERM...KEC/MULLEN
SHORT TERM...MULLEN
LONG TERM...ADAMS
AVIATION...ADAMS
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
333 PM CDT SUN AUG 24 2014
.UPDATE...
UPDATED TO EXTEND AFTERNOON RAIN CHANCES TO WEST OF THE MS RIVER.
&&
.PREV DISCUSSION... /ISSUED 232 PM CDT SUN AUG 24 2014/
DISCUSSION...
NQA RADAR BACK IN SERVICE AND JUST IN TIME TO SHOW CONVECTION
DEVELOPING IN NORTH MISSISSIPPI. TEMPERATURES WERE MAINLY IN THE
90S ACROSS THE MIDSOUTH WITH A RECORD 100 DEGREES...THE WARMEST
READING SINCE AUGUST 2012...AT THE MEMPHIS INTERNATIONAL AIRPORT.
FOR THE REMAINDER OF TODAY AND TONIGHT...SHORT TERM HRRR MODEL
SHOWING CONVECTION BECOMING SCATTERED BY 4 PM FOR POINTS ALONG
AND WEST OF THE MISSISSIPPI RIVER...WHICH CURRENTLY LINES UP WITH
PW`S ABOVE 1.80 INCHES. COULDN`T RULE OUT AN ISOLATED WET
MICROBURST WITH THE STRONGEST STORMS. ACTIVITY WILL WANE BY 9 PM
LEAVING SKIES PARTLY CLOUDY OVERNIGHT. THIS SHOULD HELP KEEP MORE
HEAT IN...WITH OVERNIGHT LOWS AGAIN IN THE MID AND UPPER 70S.
MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL MOVE WESTWARD ALONG
THE GULF COAST/SOUTHSIDE OF THE UPPER RIDGE...AND AS IT DOES
EASTERLY WINDS IN THE BOUNDARY LAYER AND MIDLEVELS WILL SLIDE
DRIER AIR OFF THE APPALACHIANS IN ITS WAKE. HEAT INDICES WILL
CONTINUE TO FLIRT WITH 105F TOMORROW...DESPITE MORE CLOUD COVER
AND CONVECTION. FEEL BY TUESDAY ENOUGH DRY AIR WILL HAVE
OVERSPREAD THE MIDSOUTH TO REDUCE HEAT INDICES BELOW 105F.
ISOLATED STORMS WILL BE POSSIBLE ON TUESDAY BUT MAINLY WEST OF THE
MISSISSIPPI RIVER NEAR THE FRONT EDGE OF THE DRIER AIR.
WEDNESDAY THROUGH FRIDAY...MODELS ARE IN GOOD AGREEMENT THAT THE
UPPER RIDGE WILL REMAIN OVER THE REGION...BUT STRONGER SUBSIDENCE
WILL KEEP DEWPOINTS IN THE 60S AND LOWER RAIN CHANCES TO AROUND 10
PERCENT. TEMPERATURES WILL BE IN THE LOW TO MID 90S WITH AFTERNOON
HEAT INDICES IN THE 93-100F RANGE.
NEXT WEEKEND...THE GFS AND EURO ARE BECOMING BETTER ALIGNED THAT
THE RIDGE WILL FLATTEN IN RESPONSE TO AN APPROACHING CENTRAL
PLAINS SHORTWAVE. THIS DISTURBANCE NOW APPEARS SOMEWHAT WEAKER AND
OUT OF PHASE WITH THE MAIN UPPER LEVEL FLOW. NONETHELESS MOISTURE
OUT AHEAD OF THE SYSTEM WILL MOVE OVER THE OZARKS ON SATURDAY AND
INTO THE MIDSOUTH BY EARLY SUNDAY. HAVE BUMPED UP TEMPERATURES TO
MAINLY THE LOW 90S FOR HIGHS AND KEPT A CONSERVATIVE APPROACH TO
THE RAIN CHANCES.
JAB
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS WILL PERSIST THROUGH THE NEXT 24 HOURS. WINDS
SHOULD REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD AT 5 KTS OR
LESS. THERE IS A LOW POTENTIAL FOR A STRAY THUNDERSTORM THIS
AFTERNOON OVER NORTHEAST MISSISSIPPI THAT COULD OCCUR NEAR KTUP.
AT THIS TIME...CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE LATEST
TAF FORECAST. THIS WILL BE MONITORED THROUGH THE DAY AND UPDATES
WILL BE PROVIDED IF NEEDED.
JLH
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR ALCORN-BENTON MS-CALHOUN-
CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-MARSHALL-
MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-TALLAHATCHIE-TATE-
TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
232 PM CDT SUN AUG 24 2014
.DISCUSSION...
NQA RADAR BACK IN SERVICE AND JUST IN TIME TO SHOW CONVECTION
DEVELOPING IN NORTH MISSISSIPPI. TEMPERATURES WERE MAINLY IN THE
90S ACROSS THE MIDSOUTH WITH A RECORD 100 DEGREES...THE WARMEST
READING SINCE AUGUST 2012...AT THE MEMPHIS INTERNATIONAL AIRPORT.
FOR THE REMAINDER OF TODAY AND TONIGHT...SHORT TERM HRRR MODEL
SHOWING CONVECTION BECOMING SCATTERED BY 4 PM FOR POINTS ALONG
AND WEST OF THE MISSISSIPPI RIVER...WHICH CURRENTLY LINES UP WITH
PW`S ABOVE 1.80 INCHES. COULDN`T RULE OUT AN ISOLATED WET
MICROBURST WITH THE STRONGEST STORMS. ACTIVITY WILL WANE BY 9 PM
LEAVING SKIES PARTLY CLOUDY OVERNIGHT. THIS SHOULD HELP KEEP MORE
HEAT IN...WITH OVERNIGHT LOWS AGAIN IN THE MID AND UPPER 70S.
MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL MOVE WESTWARD ALONG
THE GULF COAST/SOUTHSIDE OF THE UPPER RIDGE...AND AS IT DOES
EASTERLY WINDS IN THE BOUNDARY LAYER AND MIDLEVELS WILL SLIDE
DRIER AIR OFF THE APPALACHIANS IN ITS WAKE. HEAT INDICES WILL
CONTINUE TO FLIRT WITH 105F TOMORROW...DESPITE MORE CLOUD COVER
AND CONVECTION. FEEL BY TUESDAY ENOUGH DRY AIR WILL HAVE
OVERSPREAD THE MIDSOUTH TO REDUCE HEAT INDICES BELOW 105F.
ISOLATED STORMS WILL BE POSSIBLE ON TUESDAY BUT MAINLY WEST OF THE
MISSISSIPPI RIVER NEAR THE FRONT EDGE OF THE DRIER AIR.
WEDNESDAY THROUGH FRIDAY...MODELS ARE IN GOOD AGREEMENT THAT THE
UPPER RIDGE WILL REMAIN OVER THE REGION...BUT STRONGER SUBSIDENCE
WILL KEEP DEWPOINTS IN THE 60S AND LOWER RAIN CHANCES TO AROUND 10
PERCENT. TEMPERATURES WILL BE IN THE LOW TO MID 90S WITH AFTERNOON
HEAT INDICES IN THE 93-100F RANGE.
NEXT WEEKEND...THE GFS AND EURO ARE BECOMING BETTER ALIGNED THAT
THE RIDGE WILL FLATTEN IN RESPONSE TO AN APPROACHING CENTRAL
PLAINS SHORTWAVE. THIS DISTURBANCE NOW APPEARS SOMEWHAT WEAKER AND
OUT OF PHASE WITH THE MAIN UPPER LEVEL FLOW. NONETHELESS MOISTURE
OUT AHEAD OF THE SYSTEM WILL MOVE OVER THE OZARKS ON SATURDAY AND
INTO THE MIDSOUTH BY EARLY SUNDAY. HAVE BUMPED UP TEMPERATURES TO
MAINLY THE LOW 90S FOR HIGHS AND KEPT A CONSERVATIVE APPROACH TO
THE RAIN CHANCES.
JAB
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS WILL PERSIST THROUGH THE NEXT 24 HOURS. WINDS
SHOULD REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD AT 5 KTS OR
LESS. THERE IS A LOW POTENTIAL FOR A STRAY THUNDERSTORM THIS
AFTERNOON OVER NORTHEAST MISSISSIPPI THAT COULD OCCUR NEAR KTUP.
AT THIS TIME...CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE LATEST
TAF FORECAST. THIS WILL BE MONITORED THROUGH THE DAY AND UPDATES
WILL BE PROVIDED IF NEEDED.
JLH
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR ALCORN-BENTON MS-CALHOUN-
CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-MARSHALL-
MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-TALLAHATCHIE-TATE-
TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
343 PM CDT SUN AUG 24 2014
.SHORT TERM...
DESPITE OF A WESTWARD EXPANSION OF WEAK RIDGING ALOFT AND VERY
LITTLE IF ANY SURFACE FEATURES...AN ADEQUATE BOOST IN THETA-E EARLIER
TODAY SUPPLIED MUCH OF THE AREA WITH DEEPER MOISTURE NECESSARY FOR
SOME DIURNALLY DRIVEN TSTORMS. NON-HIGH RES MODELS HAVE LARGELY
MISSED THE BOAT SO FAR TODAY WITH THE EXPERIMENTAL MODELS PLAYING
THE ROLE OF THE DARK HORSE. RAP DATA SHOW THE RICHEST PWATS OF 1.3
INCHES CONFINED EAST OF A BROWNFIELD TO SILVERTON LINE WITH
GENERALLY ONE INCH OR LESS FARTHER WEST. ENVIRONMENT IN THE RICHER
PWATS IS CHARACTERIZED BY SBCAPES OF 1200-2500 J/KG WITH WEAK SHEAR.
THIS THEME WILL PERSIST THROUGH MID-EVENING AT WHICH POINT TSTORMS
WILL DWINDLE...BUT UNTIL THEN WE EXPECT ADDITIONAL STRONG TO PERHAPS
BRIEFLY SEVERE PULSE MODES WITH MICROBURSTS THE PRIMARY HAZARD.
BY MONDAY MORNING...DEEPER MONSOONAL MOISTURE WILL BE TUGGED NORTH
INTO NEW MEXICO AROUND THE ZONAL RIDGE AXIS STILL POISED FIRMLY OVER
THE SOUTH PLAINS. HEIGHT FIELDS ON THE WESTERN PERIPHERY OF THIS
RIDGE ARE NOT SHOWN TO BUILD ANY...SO THE OPPORTUNITY WILL EXIST FOR
ANOTHER ROUND OF SOLAR-POWERED TSTORMS MAINLY NEAR THE NM STATE LINE
WHERE OCCASIONAL DISTURBANCES ARE PROGGED TO LIFT NORTH FROM
CHIHUAHUA. OTHERWISE...WE CONTINUE TO SIDE WITH THE WARMER SPECTRUM
OF MOS GUIDANCE FOR BOTH LOWS AND HIGHS GIVEN THE RECENT OBSERVED
TRENDS.
&&
.LONG TERM...
COOLER WEATHER IS ON THE WAY AS WELL AS A SHOT FOR RAIN. BUT BEFORE
WE GET THERE...WARM AND DRY WEATHER WILL CONTINUE TO DOMINATE US AS
HIGH PRESSURE TO OUR EAST EXTENDS OVER THE REGION. OUR NORTHWESTERN
ZONES WILL HAVE A BIT OF A REPRIEVE MONDAY NIGHT AS A WEAKNESS
PROPAGATES AROUND THE WESTERN EDGE OF THE RIDGE. THE WEAKNESS MAKES
USE OF A SURFACE TROF LOCATED OVER THE SOUTHWESTERN TX PANHANDLE AND
FIRES SCATTERED CONVECTION IN THAT REGION. CHANCES ARE ONLY SLIGHT
AS THE AVAILABLE MONSOONAL MOISTURE ONLY COVERS A VERY SMALL AREA
WHICH COINCIDES WITH THE SURFACE TROF. BY TUESDAY AND INTO
WEDNESDAY...THE RIDGE TO OUR EAST BUILDS FURTHER WEST INHIBITING
CHANCES FOR ANY RAIN...HOWEVER A LOW AWAITS US OVER THE GREAT BASIN
AND IS READY TO MOVE IN AND DEFEAT THE EVIL RIDGE. WITH THE
EXCEPTION OF THE GFS...MODELS HAVE BEEN IN DECENT AGREEMENT WITH
HANDLING OF THE LOW THE PAST SEVERAL RUNS. THE 12Z RUN YIELDED THE
GFS SLOWING THE EASTWARD PROGRESSION OF THE LOW AND IS MORE IN LINE
WITH THE OTHER MODELS. THE LOW WILL INITIALLY START OFF CLOSED AS IT
MOVES ACROSS THE ROCKIES INTO THE CENTRAL PLAINS DURING WHICH TIME
IT WILL SLOWLY BECOME AN OPEN WAVE. BY LATE WEDNESDAY A COLD FRONT
SHOULD BE KNOCKING ON OUR DOOR. THE TIMING OF THE FRONT IS SOMEWHAT
IN QUESTION WITH TIMINGS RANGING FROM EARLY TO LATE THURSDAY...WITH
THURSDAY MORNING BEING THE TIMING CHOICE FOR THE TIME BEING. RAIN
CHANCES WILL EXIST ALONG THE FRONT...ESPECIALLY AS THE UPPER LEVEL
LOW PUSHES INTO THE REGION. PWATS OVER 1.3 INCHES WILL BE MORE THAN
ENOUGH TO AID IN MODERATE RAINFALL AMOUNTS. RAIN CHANCES WILL BE
HIGHEST THURSDAY NIGHT INTO EARLY FRIDAY AS A JET MAX PUSHES IN FROM
THE WEST ON THE SOUTHEAST SIDE OF THE LOW. AS OF NOW THE JET MAX IS
GREATEST OVER OUR SOUTHEASTERN ZONES. THIS COMBINED WITH A DIFFLUENT
UPPER PATTERN SHOULD BE MORE THAN EFFICIENT IN DEVELOPING PRECIP.
THE LOW WILL HAVE AN EXTENDED VISIT AND REMAIN OVERHEAD THROUGH LATE
SUNDAY BEFORE ZONAL FLOW TAKES OVER. TEMPERATURES WILL BE RELATIVELY
COOL IN THE SENSE OF TEMPS WILL BE AROUND SEASONAL AVERAGES BUT
COOLER THAN THEY WILL BE EARLIER THIS WEEK. DEPENDING ON THE
STRENGTH OF THE FRONT...SOME AREAS SUCH AS THE TEXAS PANHANDLE MAY
SEE BELOW AVERAGE TEMPS AS COOL AIR OVER MT INTO CA WILL BE PUSHED
SOUTHWARD. AS OF THIS AFTERNOON...PARTS OF INTERIOR MT HAVE FAILED
TO REACH INTO THE 50S. AS OF NOW THE COOLEST AIR WITH THE FRONT
LATER THIS WEEK SHOULD STAY TO OUR NORTH WITH THE COOL SIDE OF THE
FORECAST BEING IN THE UPPER 50S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 92 63 90 62 / 10 20 20 10 10
TULIA 69 95 65 93 64 / 10 10 20 10 10
PLAINVIEW 65 95 64 92 64 / 10 10 10 10 10
LEVELLAND 67 94 65 91 64 / 10 10 20 10 10
LUBBOCK 72 96 68 94 68 / 10 10 10 10 10
DENVER CITY 67 95 65 92 65 / 10 10 10 10 10
BROWNFIELD 66 96 66 93 66 / 10 10 10 10 10
CHILDRESS 73 101 72 98 72 / 20 10 10 10 10
SPUR 70 100 68 96 68 / 20 0 10 0 10
ASPERMONT 75 102 72 99 71 / 10 0 10 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/51
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 600 PM CDT SUN AUG 24 2014
MONITORING CONVECTIVE TRENDS ACROSS THE REGION...WITH A
PARTICULAR FOCUS ON SOUTHEAST MINNESOTA INTO THE EARLY EVENING
HOURS. THE 24.22Z RAP ANALYSIS SHOWS A VERY UNSTABLE AIR MASS IS
CENTERED ALONG THE MISSISSIPPI RIVER WITH UPWARDS OF 3000-5000
J/KG OF SURFACE BASED CAPE NOSING UP TOWARD THE TWIN CITIES.
HOWEVER...THIS AIR MASS APPEARS TO BE CAPPED OFF DUE TO THE LACK
OF A CUMULUS FIELD ACROSS SE MN/NE IA/W WI. ALSO...DEEP WIND SHEAR
IS ALSO VERY LACKING THIS FAR SOUTH...SO WHILE SOME CONVECTION HAS
INITIATED ACROSS NC IA/SC MN...IT HAS BEEN VERY PULSEY AND CAN NOT
MAINTAIN ITSELF FOR VERY LONG. FURTHER NORTH WHERE THERE IS DEEPER
WIND SHEAR AND BETTER CONVERGENCE IN THE SURFACE FEATURES...STORMS
ARE QUICKLY GOING SEVERE. WHILE THERE WILL BE ABOUT A 2-3 HOUR
PERIOD FROM NOW THROUGH 9 PM WHERE THIS CONVECTION WILL COME
THROUGH MOWER/DODGE/OLMSTED COUNTIES...EXPECTING THAT IT WILL STAY
UNORGANIZED AND NOT SEVERE. SOME OF THIS CONVECTION COULD MAKE IT
INTO ROCHESTER AROUND 7PM...BUT THE NORTHERN EDGE OF THE CAP
APPEARS TO BE AT OR JUST TO THE NORTH OF THE CITY...WHICH WOULD
HELP TO KEEP THEM DRY THIS EVENING. BEYOND THIS...THERE APPEARS TO
BE A SECOND WAVE OF CONVECTION POSSIBLE OVERNIGHT AS THE MAIN
TROUGH/SURFACE COLD FRONT APPROACH FROM THE WEST. INSTABILITY
REMAINS HIGH OVERNIGHT...BUT THE OVERALL SHEAR IS LACKING WHICH
SHOULD KEEP THIS CONVECTION UN-ORGANIZED AND MAINLY NOT SEVERE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE MAIN CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER
NORTH DAKOTA WITH A COLD FRONT TRAILING SOUTH THROUGH WESTERN
MINNESOTA INTO NEBRASKA. WATER VAPOR IMAGERY SHOWS A WOUND UP
UPPER LEVEL LOW OVER EASTERN MONTANA THAT WAS LIFTING TO THE
NORTHEAST.
THE 24.12Z MODELS ARE ALL IN REASONABLY GOOD AGREEMENT WITH THE
HANDLING OF THE UPPER LEVEL SYSTEM. IT WILL CONTINUE TO MOVE
NORTHEAST REACHING WESTERN ONTARIO BY MONDAY EVENING. THE MAIN
SHORT WAVE TROUGH WITH THIS SYSTEM IS VERY NEAR THE UPPER LEVEL
LOW AND IS EXPECTED TO REMAIN THAT WAY. THIS TAKES THE PV
ADVECTION IN THE 500-300 MB LAYER FROM EASTERN NORTH DAKOTA ACROSS
NORTHWEST MINNESOTA INTO ONTARIO. THIS WILL TAKE THE BULK OF THE
UPPER LEVEL FORCING WELL NORTH OF THE REGION BUT SOME UPPER LEVEL
DIVERGENCE SHOULD SPREAD ACROSS THE AREA TONIGHT AS THE RIGHT
ENTRANCE REGION OF THE UPPER LEVEL JET MOVES OVER. AS THE FRONT
MOVES IN TONIGHT...SOME WEAK FRONTOGENESIS SHOULD OCCUR IN THE
850-500 MB LAYER. GOOD LOW LEVEL WARM AIR ADVECTION AHEAD OF THE
FRONT WILL HELP TO GENERATE 4 TO 6 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS SURFACE
EXPECTED TO BE INTO THE AREA FROM LATE EVENING THROUGH THE
OVERNIGHT HOURS. THE 24.12Z SOUNDING FROM KMPX SHOWS A STRONG CAP
IS IN PLACE BETWEEN 850 AND 700 MB AND THE CONCERN BECOMES WHETHER
THE FORCING WILL BE STRONG ENOUGH TO BREAK THE CAP. THE 24.12Z NAM
BUFKIT SOUNDINGS SUGGEST THAT THE CAP MAY WEAKEN BUT NOT TOTALLY
BREAK AND THIS IS REFLECTED IN THE MODEL ONLY PRODUCING SOME
SCATTERED ACTIVITY ALONG THE FRONT AS IT COMES THROUGH. THE
24.12Z GFS AND ECMWF SHOW MUCH MORE QPF ALONG THE FRONT SUGGESTING
THE CAP WILL BREAK. THE SHORT TERM MESO-MODELS ARE ABOUT AS
EQUALLY SPLIT. THE 24.12Z HI-RES ARW LOOKS TO HOLD THE CAP IN
PLACE WITH ALMOST NO ACTIVITY OVER THE AREA...WHILE THE HI-RES NMM
IS CLOSER TO THE NAM WITH JUST SOME SCATTERED ACTIVITY. THE 24.12Z
SPC WRF LOOKS TO DISSIPATE THE CAP AS EARLY AS LATE THIS AFTERNOON
WITH LOTS OF CONVECTION DEVELOPING ACROSS MINNESOTA AND MOVING
ACROSS THE AREA IN THE NIGHT. OUTPUT FROM THE 24.12Z HOP WRF IS
ALSO SPLIT WITH A COUPLE OF MEMBERS DEVELOPING LOTS OF CONVECTION
AND THE OTHER TWO STAYING WITH JUST SCATTERED ACTIVITY. IF THE CAP
WOULD BREAK...THE BEST CHANCE FOR THIS TO OCCUR WOULD BE ACROSS
THE NORTHERN SECTIONS OF THE FORECAST AREA CLOSER TO THE DYNAMIC
FORCING AND WILL MAINTAIN THE LIKELY RAIN CHANCES ACROSS THAT AREA
WHILE TAPERING DOWN TO 30 TO 40 PERCENT CHANCE ACROSS THE SOUTH.
SOME THREAT OF SEVERE ACROSS THE NORTH AS WELL IF THE CAP CAN
BREAK. PLENTY OF INSTABILITY WILL REMAIN IN PLACE AHEAD OF THE
FRONT WITH THE NAM SHOWING 1000-1500 J/KG OF ML CAPE ALONG WITH 40
KNOTS OF 0-3KM SHEAR. DAMAGING WINDS AND HEAVY RAIN SHOULD BE THE
MAIN THREATS AS WARM CLOUD DEPTHS WILL REMAIN IN THE 3.5 TO 4 KM
RANGE AHEAD OF THE FRONT. MAY ALSO HAVE TO AWARE OF A SPIN UP
TORNADO THREAT AS A DIFFERENTIAL HEATING BOUNDARY IS IN PLACE ON
THE CLOUD EDGE. IF THIS BOUNDARY MAINTAINS ITSELF INTO THE
EVENING...THE NAM INDICATES THE 0-1KM SHEAR WILL INCREASE TO
AROUND 25 KNOTS.
THE FRONT SHOULD THEN PASS THROUGH THE AREA MONDAY WITH THE
POSSIBILITY OF SOME SCATTERED ACTIVITY ALONG IT. NOT MUCH FORCING
ALONG THE FRONT BUT COULD SEE A DIURNAL INCREASE IN THE ACTIVITY
DURING THE AFTERNOON WHEN THE ML CAPE SHOULD AGAIN BE IN THE
2000-3000 J/KG RANGE.
THE MODELS THEN HAVE REALLY TRENDED TOWARD PUSHING THIS FRONT
FARTHER SOUTH FROM MONDAY NIGHT INTO TUESDAY NIGHT AS THE HIGH
PRESSURE BUILDING IN BEHIND IT IS MUCH STRONGER. MODELS CONTINUE
TO SHOW A SHORT WAVE TROUGH MOVING ALONG THE UPPER LEVEL RIDGE
AXIS AND INTERACTING WITH THE FRONT. IF THE FRONT DOES PUSH AS FAR
SOUTH AS THE MODELS ARE CURRENTLY INDICATING...THIS WOULD PLACE
THE HIGHEST RAIN CHANCES SOUTH OF THE IOWA/MINNESOTA BORDER. WILL
MAINTAIN SOME 50 TO 60 PERCENT CHANCES FROM MONDAY NIGHT INTO
TUESDAY NIGHT...BUT LIMIT THEM TO THE SOUTHERN SECTIONS.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE FRONT IS EXPECTED TO STILL NOT BE TOO FAR SOUTH OF THE AREA
BY THE MIDDLE OF THE WEEK. THE 24.12Z ECMWF AND GFS IN DECENT
AGREEMENT OF BRINGING ANOTHER SHORT WAVE TROUGH ACROSS THE TOP OF
THE RIDGE AXIS WITH A SURFACE LOW MOVING ALONG THE FRONT. BASED ON
THIS...WILL HAVE UP TO 50 PERCENT CHANCES ACROSS THE SOUTH FROM
WEDNESDAY INTO THURSDAY NIGHT. THE RAIN CHANCES SHOULD THEN
DIMINISH TO CLOSE OUT THE WEEK INTO THE WEEKEND AS HIGH PRESSURE
BUILDS IN BEHIND THE MID WEEK SYSTEM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1221 PM CDT SUN AUG 24 2014
VISIBLE SATELLITE SHOWING STRATUS MIXING OUT NICELY FROM WEST TO
EAST AS INCREASING SOUTHERLY FLOW/DAYTIME HEATING SCOURS OUT THE
LOWER BOUNDARY LAYER. LOOK FOR VFR CONDITIONS GOING INTO THE
AFTERNOON HOURS WITH SOUTH WINDS IN THE 10-20KT RANGE. A FEW
HIGHER GUST AROUND 25KT CAN BE EXPECTED AT KRST.
A COLD FRONT WILL THEN PUSH INTO THE AREA LATER THIS
EVENING...SPARKING OFF A LINE OF SHRA/TSRA. MODELS IN PRETTY GOOD
AGREEMENT THAT THE SOUTHERN END OF THIS LINE OF SHRA/TS WILL
BEGIN AFFECTING KRST AROUND 03-04Z AND KLSE 05-06Z. PLAN ON A FEW
HOUR WINDOW OF SHRA/TSRA ACTIVITY. LOOKS LIKE CIGS SHOULD STAY IN
THE VFR RANGE WITH VIS POSSIBLY DIPPING INTO MVFR FOR A LITTLE
BIT IN TSRA/BR. MODELS INDICATING A BAND OF STRATUS WITH THE
PASSAGE OF THE COLD FRONT IN THE 13-18Z TIMEFRAME. NOT CONFIDENT
YET AT THIS POINT IF THIS WILL CONSTITUTE A CEILING OR NOT. WILL
KEEP AN EYE ON IT.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN AUG 24 2014
HEAVY RAIN WILL BE A THREAT WITH ANY STORMS THAT DEVELOP TONIGHT.
WARM CLOUD DEPTHS WILL BE IN THE 3.5 TO 4 KM RANGE WITH
PRECIPITABLE WATERS APPROACHING TWO INCHES. THE CONCERN FOR HEAVY
RAIN AND POSSIBLE FLOODING WITH THE STALLED FRONT FOR THE EARLY
PART OF THE WEEK ARE DIMINISHING WITH THE FRONT EXPECTED TO PUSH
FARTHER SOUTH. THE HIGHEST AXIS OF PRECIPITABLE WATERS SHOULD LAY
UP SOUTH OF THE FRONT ACROSS SOUTHERN IOWA/NORTHERN MISSOURI INTO
ILLINOIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...04
LONG TERM...04
AVIATION...DAS
HYDROLOGY...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW UPPER LEVEL
LOW PRESSURE OVER EASTERN MONTANA AND A DOUBLE BARRELED SURFACE LOW
OVER NORTH DAKOTA. A WARM FRONT EXTENDS FROM THIS SURFACE LOW OVER
SOUTHWEST WISCONSIN...WHICH MARKS THE TRANSITION FROM MOSTLY CLOUDY
SKIES TO CLEAR CONDITIONS. A COLD FRONT EXTENDS SOUTHWARD OVER THE
CENTRAL PLAINS AND IS LARGELY INACTIVE AT THIS HOUR THOUGH THAT
MIGHT BE CHANGING OVER CENTRAL MINNESOTA WHERE ML CAPES HAVE
EXCEEDED 2000 J/KG. A FEW OTHER ELEVATED STORMS CONTINUE TO DEVELOP
OVER NORTHWEST WISCONSIN WITHIN THE TAIL END OF A VORT MAX. WILL
ADD A CHANCE TO N-C WISCONSIN BETWEEN 21Z AND 00Z. AS THE UPPER LOW
AND COLD FRONT MOVE EAST...THUNDERSTORM AND SEVERE WEATHER CHANCES
ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE LARGE UPPER LOW WILL MOVE ACROSS NORTH DAKOTA INTO THE
LAKE WINNIPEG REGION. MID-LEVEL HEIGHT FALLS FROM THE SYSTEM WILL
MOVE INTO THE WESTERN GREAT LAKES...WHICH WILL HELP PUSH A WEAK COLD
FRONT INTO WESTERN WISCONSIN AFTER MIDNIGHT. CONVERGENCE ALONG THE
FRONT IS RELATIVELY WEAK...BUT ELEVATED INSTABILITY APPROX 1000-1500
J/KG (ROUGH ESTIMATE) WILL MOVE INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN AFTER MIDNIGHT. BECAUSE OF THE WEAK FORCING...KEPT
CHANCES OF PRECIP IN THE SCATTERED RANGE. THE MAGNITUDE OF CAPE AND
WIND SHEAR AROUND 30 KTS WOULD SUPPORT A CHANCE OF STRONG STORMS
THAT COULD PRODUCE NEAR SEVERE HAIL AND WIND GUSTS. WILL LEAVE A
MENTION OF THIS POSSIBILITY IN THE HWO. THE MESO MODELS CONTINUE TO
SHOW CONVECTION DEVELOPING OVER CENTRAL MINNESOTA LATER THIS
AFTERNOON BEFORE TRACKING THE STORMS INTO NORTH-CENTRAL WISCONSIN
AFTER 06Z. THIS STILL SEEMS POSSIBLE BASED ON THE DESTABILIZATION
TAKING PLACE OVER CENTRAL MINNESOTA. THE STORMS SHOULD WEAKEN AS
THEY MOVE EAST LATE TONIGHT DUE TO DIMINISHING INSTABILITY.
OTHERWISE...LOOK FOR A MUGGY EVENING WITH LOWS DROPPING INTO THE
MIDDLE AND UPPER 60S.
MONDAY...THE FRONT WILL MAKE LITTLE PROGRESS TO THE EAST AND INTO
NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. SPOTTY SHOWERS AND
STORMS WILL BE POSSIBLE AHEAD OF THE FRONT DURING THE MORNING ACROSS
MUCH OF THE AREA. ASSUMING COVERAGE IS NOT MORE THAN
ADVERTISED...LOW LEVEL SOUTHWEST WINDS WILL PUSH TEMPS INTO THE
UPPER 80S OR LOWER 90S OVER THE EASTERN FORECAST AREA. COMBINED
WITH DEWPOINTS AROUND 70 DEGREES...ML CAPES ARE PROJECTED TO REACH
2K-3K J/KG WITH BULK SHEARS AROUND 30 KTS. CONVERGENCE ALONG THE
FRONT WILL REMAIN WEAK BUT CANNOT RULE OUT ISOLATED OR SCATTERED
STRONG TO SEVERE STORMS OVER THE EAST DURING THE AFTERNOON WITH THAN
KIND OF INSTABILITY AND SHEAR. DRIER MID-LEVEL AIR WILL WORK INTO
CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON...WHICH
WILL MAKE IT HARDER FOR STORMS TO INITIATE. THE COMBINATION OF HEAT
AND HUMIDITY WILL PUSH HEAT INDICES INTO THE MIDDLE 90S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
MODELS CONTINUE TO INDICATE A RATHER AMPLIFIED MEAN FLOW PATTERN ACROSS
THE CONUS WITH AN UPPER TROF CURRENTLY OVER THE INTER MOUNTAIN
WEST AND SIG RIDGE OVER THE EASTERN LAKES. THE MOVEMENT OF UPPER
LOW OUT OF TROF INTO THE WESTERN LAKES EARLY IN THE PERIOD WILL BE
THE PRIMARY WEATHER FEATURE TO IMPACT OUR WEATHER. BY LATE THIS
WEEK...MODELS CONTINUE TO SHOW LINGERING PIECE OF TROF MEANDERING
INTO THE CENTRAL U.S. THE MOVEMENT OF THIS FEATURE CONTINUES TO
SLOW AS IT REMAINS CUT OFF FROM MAIN BAND OF WESTERLIES EXPECTED
TO LIE OVER SOUTHERN CANADA. FORECAST CONFIDENCE LOW THU NIGHT
ONWARD.
TREND IN SHORTER RANGE IS TO CONTINUE TO SLOW PASSAGE OF COLD
FRONT MONDAY WITH FRONT STILL BISECTING CWA AT 00Z TUE. HAVE
CONTINUE SCATTERED/CHANCE POPS MAINLY SOUTH AND EAST GIVEN
AVAILABLE INSTABILITY. LITTLE DYNAMICS BESIDES FRONT TO SUPPORT
GOING ANY HIGHER WITH POPS.
CONSISTENCY SEEN IN MODELS TO PUSH FRONT AND PCPN MAINLY SOUTH OF
CWA AS HIGH PRESSURE AND DRIER AIR MASS MOVES IN OVER NORTHERN WI
TUE INTO THU. CONCERN THIS PERIOD ON TEMPS. DRIER AIR...SUN AND
LOW LEVEL TEMPS AT OR SLIGHTLY BELOW NORMAL SHOULD SUPPORT TEMPS IN
THE LOWER TO MIDDLE 70S. WILL HAVE EAST FLOW OFF LAKE THOUGH LAKE
SURFACE TEMPS NOW IN MID TO UPPER 60S SO HAVE CONFINED COOLING TO
CLOSER TO THE COAST. HAVE BUMPED MAX TEMPS UP A BIT MID WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1148 AM CDT SUN AUG 24 2014
POCKET OF IFR CIGS AND VSBYS OVER NORTH-CENTRAL
WISCONSIN WILL RETURN TO MVFR THIS AFTERNOON AS DAYTIME HEATING
MIXES OUT SOME OF THE LOW LEVEL MOISTURE. THIS WILL BE A SLOW
PROCESS MOST AREAS HAVE A CHANCE TO SEE VFR LATE THIS AFTERNOON INTO
EARLY THIS EVENING. THEN A WEAK FRONT WILL SLOW ITS FORWARD
PROGRESS AS IT MOVES INTO THE REGION TONIGHT AND HANGS AROUND ON
MONDAY. THE FRONT IS EXPECTED TO BRING A BROKEN LINE OF SHOWERS AND
THUNDERSTORMS TO CENTRAL AND NORTH-CENTRAL WISCONSIN AFTER
MIDNIGHT...BUT THE LINE SHOULD BE WEAKENING AS IT MOVES EAST INTO
NORTHEAST WISCONSIN. AS A RESULT...LEFT ANY MENTION OF
PRECIPITATION OUT OF THE FOX VALLEY AND LAKESHORE TAF SITES. AREAS
OF LOW CLOUDS AND FOG WILL ALSO LIKELY REDEVELOP LATER TONIGHT.
BETTER FLYING CONDITIONS WILL RETURN ON MONDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1221 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 1221 PM CDT SUN AUG 24 2014
VISIBLE SATELLITE SHOWING STRATUS ERODING FROM WEST TO EAST ACROSS
THE FORECAST AREA AS SOUTHERLY FLOW INCREASES AND DAYTIME HEATING MIXES
OUT THE LOWER BOUNDARY LAYER MOISTURE. RAP SHOWING AXIS OF 26-30C
AIR NOSING INTO THE AREA THIS AFTERNOON IN ADVANCE OF A COLD FRONT
PUSHING INTO CENTRAL MN/WESTERN IA. WILL HOLD STEADY ON HIGHS
TOPPING OFF IN THE MIDDLE 80S ACROSS CENTRAL WISCONSIN AND UPPER
80S/AROUND 90 ALONG AND WEST OF THE MISSISSIPPI RIVER. WITH DEW
POINTS IN THE 70S...PLAN ON MAXIMUM HEAT INDICES IN THE 95-100
DEGREE RANGE IN THE 2-6PM TIME FRAME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 230 AM CDT SUN AUG 24 2014
HOT AND HUMID TODAY. 850 MB SREF TEMP ANOMALIES PEGGING +1.5 TODAY
WHILE 925 MB TEMPS RANGE FROM 26-28 C. HIGHS SHOULD REACH 90 FOR
MANY LOCATIONS. MEANWHILE...SFC DEWPOINTS WILL LIKELY HOLD IN THE
LOW 70S THROUGH THE DAY. THE MIX OF HOT/HUMID AIR WILL PLACE HEAT
INDICES AROUND 100 DEGREES FOR MUCH OF THE FORECAST AREA THIS
AFTERNOON. HOWEVER...SOME UNCERTAINTY TO HOW MUCH CLOUD COVER WILL
BE AROUND TODAY. LOW STRATUS COULD LINGER ACROSS WESTER/CENTRAL WI
THROUGH THE MORNING...WHILE SOME HIGH CLOUDS START TO TRACK INTO
AREAS WEST OF THE RIVER THIS AFTERNOON. ALL WOULD TEMPER TEMPS BACK
A FEW DEGREES...AND THUS DROP THE HEAT INDICES DOWN. AT THIS
TIME...DON/T FEEL A HEAT ADVISORY WILL BE NEEDED. IF TEMPS WARM A
DEGREE OR TWO MORE THAN EXPECTED...ONE MAY BE NECESSARY.
TONIGHT...AN UPPER LEVEL SHORTWAVE TROUGH WILL LIFT NORTHEAST ACROSS
THE NORTHERN PLAINS AND INTO SOUTHERN CANADA. AN ASSOCIATED COLD
FRONT WILL LEAD WELL AHEAD OF THE TROUGH...MOVING INTO WESTERN WI
TOWARD 06Z. A RIBBON OF LOW LEVEL MOISTURE WILL RUN AHEAD OF THE
FRONT...WITH MUCAPES FROM 1-2K J/KG. PLENTY OF FUEL FOR THE BOUNDARY
TO FIRE SHOWERS/STORMS. THE DEEPER SHEAR IS WEST OF THE INSTABILITY
AXIS...BUT ENOUGH 0-3KM SHEAR THAT SOME STORM ORGANIZATION COULD
OCCUR AND POTENTIALLY A STRONG WIND THREAT. MOSTLY...HEAVY RAIN AND
LARGE HAIL WOULD BE THE MAIN THREATS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 230 AM CDT SUN AUG 23 2014
NAM/GFS/ECMWF CONTINUE TO POINT TO THE SAME SOLUTION THEY HAVE BEEN
SUGGESTING FOR THE PAST FEW DAYS...ONE THAT WILL BRING ROUNDS OF
PCPN WITH THE POTENTIAL FOR HEAVY RAIN AND STRONGER STORMS.
SEVERAL FACTORS WILL PLAY ROLES IN THE PRECIPITATION CHANCES OVER
THE NEXT FEW DAYS.
1) COLD FRONT. THE COLD FRONT THAT TRACKS ACROSS THE REGION LATE
TONIGHT WILL GRADUALLY ORIENTATE ITSELF AS A WEST-EAST STATIONARY
FRONT ACROSS CENTRAL IA-NORTHERN ILL FOR THE FIRST HALF OF THE NEW
WORK WEEK. ESSENTIAL...IT GETS STUCK UNDER THE BROAD UPPER LEVEL
RIDGE...AND IS NOT EXPECTED TO GET A NUDGE OUT OF THE REGION UNTIL
LATER ON THU WHEN A SHORTWAVE TROUGH DRIVES EASTWARD ACROSS THE MID
MISSISSIPPI RIVER VALLEY.
WHERE THE FRONT RESTS WILL BE THE MAIN REGION FOR STORM DEVELOPMENT.
2) LOW LEVEL JET/MOISTURE TRANSPORT. MODELS POINT TO THE NOSE OF THE
850 MB JET AND MOISTURE TRANSPORT FOCUSING INTO WESTERN/SOUTHERN IA
MON-THU NIGHTS...IMPINGING ON AND ACROSS THE STATIONARY FRONT. NIGHT
TIME MCS/S ARE LIKELY IN THIS REGION ALL THESE NIGHTS...TRACKING
EAST OVERNIGHT. ASSOCIATED MCVS WILL LIKELY BE ANOTHER SOURCE FOR
FORCING.
3) INSTABILITY. NAM AND GFS BUILD UPWARDS OF 4000+ J/KG OF SBCAPE
ALONG AND SOUTH OF THE BOUNDARY. ELEVATED INSTABILITY DOES SLOPE
NORTH ACROSS THE BOUNDARY. FOR THE FORECAST AREA...THE BULK OF THE
INSTABILITY WOULD STAY SOUTH...BUT ENOUGH IN THE VICINITY TO SUPPORT
STORM DEVELOPMENT.
4) WIND SHEAR. THE DEEPER-STRONGER SHEAR IS EXPECTED TO LIE WELL
NORTH OF THE STATIONARY FRONT...IN THE COLDER AIR. THERE COULD BE
ENOUGH OVERLAP OF FAVORABLE SHEAR INTO THE INSTABILITY AXIS TO
FURTHER SUPPORT STORM DEVELOPMENT AND UPDRAFTS. STABLE SFC LAYER
NORTH OF THE FRONT WILL INHIBIT THE GUST POTENTIAL...BUT WON/T
COMPLETELY RULE IT OUT. ALONG AND SOUTH OF THE FRONT THE STRONG WIND
POTENTIAL INCREASES. HEAVY RAIN WILL OCCUR. HAIL WILL BE POSSIBLE
BOTH SIDES OF THE BOUNDARY.
WITH SEVERAL FACTORS FAVORING HEAVY RAIN...ALONG WITH DAILY/NIGHTLY
CHANCES FOR STORMS...THE HYDRO CONCERNS ARE INCREASING. MORE ON THE
THREAT FOR RIVER AND FLASH FLOOD IMPACTS IN THE HYDRO SECTION BELOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1221 PM CDT SUN AUG 24 2014
VISIBLE SATELLITE SHOWING STRATUS MIXING OUT NICELY FROM WEST TO
EAST AS INCREASING SOUTHERLY FLOW/DAYTIME HEATING SCOURS OUT THE
LOWER BOUNDARY LAYER. LOOK FOR VFR CONDITIONS GOING INTO THE
AFTERNOON HOURS WITH SOUTH WINDS IN THE 10-20KT RANGE. A FEW
HIGHER GUST AROUND 25KT CAN BE EXPECTED AT KRST.
A COLD FRONT WILL THEN PUSH INTO THE AREA LATER THIS
EVENING...SPARKING OFF A LINE OF SHRA/TSRA. MODELS IN PRETTY GOOD
AGREEMENT THAT THE SOUTHERN END OF THIS LINE OF SHRA/TS WILL
BEGIN AFFECTING KRST AROUND 03-04Z AND KLSE 05-06Z. PLAN ON A FEW
HOUR WINDOW OF SHRA/TSRA ACTIVITY. LOOKS LIKE CIGS SHOULD STAY IN
THE VFR RANGE WITH VIS POSSIBLY DIPPING INTO MVFR FOR A LITTLE
BIT IN TSRA/BR. MODELS INDICATING A BAND OF STRATUS WITH THE
PASSAGE OF THE COLD FRONT IN THE 13-18Z TIMEFRAME. NOT CONFIDENT
YET AT THIS POINT IF THIS WILL CONSTITUTE A CEILING OR NOT. WILL
KEEP AN EYE ON IT.
&&
.HYDROLOGY...
ISSUED AT 230 AM CDT SUN AUG 23 2014
WARM CLOUD DEPTHS CONTINUE TO APPROACH 4 KFT ALONG AND SOUTH OF THE
FRONT WITH PWS UPWARDS OF 1.5 - 1.75 INCHES. STORMS IN THIS
ENVIRONMENT WILL BE EFFICIENT RAIN PRODUCERS...AND HEAVY RAIN WILL BE
LIKELY WITH ANY STRONGER STORM.
STORM TRACKS LOOKS MOSTLY EAST ALONG AND AROUND THE FRONT...FAVORING
TRAINING THUNDERSTORMS AND REPEATED ROUNDS OF SOAKING RAINS. THERE
COULD BE IMPACTS TO RIVER SYSTEMS IF MCS/S IMPACT THE SAME AREAS
NIGHT AFTER NIGHT. THE FLASH FLOOD THREAT WOULD ALSO INCREASE AS
GROUNDS BECOME SATURATED.
OVERALL - CURRENT MODEL SOLUTIONS WOULD KEEP THE BULK OF THE
POTENTIAL HYDRO ISSUES SOUTH OF I-90...MOSTLY NORTHEAST IA AND
SOUTHWEST WI.
A HYDROLOGIC OUTLOOK MIGHT BE NEEDED IN THE NEXT COUPLE DAYS TO
FURTHER OUTLINE THE RAINFALL-RIVER THREATS. WOULD NOT BE SURPRISED
IF FLASH FLOOD WATCHES EVENTUALLY BECOME NECESSARY LATER IN THE
WEEK.
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...DAS
HYDROLOGY....RIECK